Computer program products, apparatus, and methods for processing digital messages to recipients at destination domains is provided. A plurality of profiles are established, each profile for handling digital to a specific domain or set of domains. A request to process a plurality of outbound digital messages is handled by, for each given digital message, processing the given digital message by (i) determining a destination domain for digital messages, (ii) reading a profile for the determined destination domain for the digital messages and (iii) based on at least one parameter set in the profile: (a) sending the given digital message to the determined destination domain in accordance with the profile when permitted by the at least one parameter set in the profile, or (b) not sending the digital message to the determined destination domain when required by the at least one parameter set in the profile.

Digital message (e.g., e-mail, text messages, etc.) is an essential network service.
Many digital messaging systems that send digital messages over the Internet use protocols such as simple mail transfer protocol (SMTP), in the case of E-mail, and other protocols when the digital message is other than e-mail, to send digital messages from one server to another. The messages can then be retrieved with a client using services such as post office protocol (POP) or Internet message access protocol (IMAP). Other protocols for sending digital messages that are e-mails include, but are not limited to, POP3, X.400 International Telecommunication Union standard (X.400), and the Novell message handling service (MHS), and extended simple mail transfer protocol (ESMTP). Specifically, X.400 defines a transfer protocol for sending electronic mail between mail servers and is used in Europe as an alternative to SMTP. MHS, which was developed by Novell, is used for electronic mail on Netware networks.
SMTP transports digital messages among different hosts within the transmission control protocol/Internet protocol (TCP/IP) suite. Under SMTP, a client SMTP process opens a TCP connection to a server SMTP process on a remote host and attempts to send mail across the connection. The server SMTP listens for a TCP connection on a specific port, usually port 25, and the client SMTP process initiates a connection on that port. When the TCP connection is successful, the two processes execute a simple request-response dialogue, defined by the SMTP protocol (see RFC 821 STD 10, simple mail transfer protocol, August 1982, for details), in which the client process transmits the mail addresses of the originator and the recipient(s) for a message. When the server process accepts these mail addresses, the client process transmits the e-mail instant message. The e-mail message contains a message header and message text ("body") formatted in accordance with RFC 822 (RFC822 STD 11, Standard for the format of ARPA—Internet Text Messages, August 1982). Mail that arrives via SMTP is forwarded to a remote server or it is delivered to mailboxes on the local server. On UNIX-based systems, Sendmail is a widely used SMTP server for e-mail. Sendmail includes a POP3 server and also comes in a version for Windows NT. Microsoft Outlook is the most popular mail-agent program on Window-based systems. Similar protocols are used when the digital message is other than e-mail.
The SMTP model (RFC 821) supports both end-to-end (no intermediate message transfer agents "MTAs") and store-and-forward mail delivery methods. The end-to-end method is used between organizations, and the store-and-forward method is chosen for operating within organizations that have TCP/IP and SMTP-based networks. A SMTP client will contact the destination host's SMTP server directly to deliver the mail. It will keep the mail item from being transmitted until it has been successfully copied to the recipient's SMTP. This is different from the store-and-forward principle that is common in many other electronic mailing systems, where the mail item may pass through a number of intermediate hosts in the same network on its way to the destination and where successful transmission from the sender only indicates that the mail item has reached the first intermediate hop. The RFC 821 standard defines a client-server protocol. The client SMTP is the one which initiates the session (that is, the sending SMTP) and the server is the one that responds (the receiving SMTP) to the session request. Because the client SMTP frequently acts as a server for a user-mailing program, however, it is often simpler to refer to the client as the sender-SMTP and to the server as the receiver-SMTP. A SMTP-based process can transfer electronic mail to another process on the same network or to another network via a relay or gateway process accessible to both networks. An e-mail message may pass through a number of intermediate relay or gateway hosts on its path from a sender to a recipient.
A simple model of the components of the SMTP system is shown in FIG. 1. Systems that send digital messages other than e-mail have similar components. Referring to FIG. 1, users deal with a user agent (UA). Popular user agents for UNIX include Berkeley Mail, Elm, MH, Pine, and Mutt. The user agents for Windows include Microsoft Outlook/Outlook Express and Netscape/Mozilla Communicator. The exchange of e-mail using, for example TCP, is performed by an MTA. One MTA for UNIX systems is Sendmail, and a conventional MTA for Windows is Microsoft Exchange Server 2007. Users normally do not deal with the MTA. It is the responsibility of the system administrator to set up the local MTA. Users often have a choice, however, for their user agent. The local MTA maintains a mail queue so that it can schedule repeat delivery attempts in case a remote server is unable. Also the local MTA delivers mail to mailboxes, and the information can be downloaded by the UA (see FIG. 1). The RFC 821 standard specifies the SMTP protocol, which is a mechanism of communication between two MTAs across a single TCP connection. The RFC 822 standard specifies the format of the electronic mail message that is transmitted using the SMTP protocol (RFC 821) between the two MTAs. As a result of a user mail request, the sender-SMTP establishes a two-way connection with a receiver-SMTP. The receiver-SMTP can be either the ultimate destination or an intermediate one (known as a mail gateway). The sender-SMTP will generate commands, which are replied to by the receiver-SMTP (see FIG. 1).
A typical e-mail delivery process is as follows. Delivery processes for digital messages other than e-mail follow similar scenarios. In the following scenario, Larry at terminal 102 sends e-mail to Martha at her e-mail address: firstname.lastname@example.com. Martha can review here e-mail at terminal 102. Martha's Internet Service Provider (ISP) uses mail transfer agent MTA 106.
1. Larry composes the message and chooses send using mail user agent (MUA) 108. The e-mail message itself specifies one or more intended recipients (e.g., destination e-mail addresses), a subject heading, and a message body; optionally, the message may specify accompanying attachments.
2. MUA 108 queries a DNS server (not shown) for the IP address of the local mail server running MTA 110. The DNS server translates the domain name into an IP address, e.g., 10.1.1.1, of the local mail server.
3. User agent 108 opens an SMTP connection to the local mail server running MTA 110. The message is transmitted to the local mail server using the SMTP protocol. An MTA (also called a mail server, or a mail exchange server in the context of the Domain Name System) is a computer program or software agent that transfers electronic mail messages from one computer to another. Webster's New World Computer Dictionary, tenth edition, Wiley Publishing Inc., Indianapolis, Ind., defines an MTA as an e-mail program that sends e-mail messages to another message transfer agent. An MTA can handle large amounts of mail, can interact with databases in many formats, and has extensive knowledge of the many SMTP variants in use. Examples of high-throughput MTA systems are disclosed in U.S. patent application Ser. No. 10/857,601, entitled "Email Delivery System Using Metadata," filed May 27, 2004 as well as U.S. patent application Ser. No. 10/777,336, entitled "Email Using Queues in Non-persistent memory," filed Feb. 11, 2004, each of which is hereby incorporated by reference in its entirety. One example of an MTA system is the StrongMail MTA (Redwood Shores, Calif.). Conventional MTA programs include, but are not limited to, Sendmail, qmail, Exim, Postfix, Microsoft Exchange Server, IMail (Ipswitch, Inc.), MDaemon (Alt-N Technologies), MailEnable, Merak Mail Server, and qmail.
4. MTA 110 queries a DNS server (not shown) for the MX record of the destination domain, e.g., example.org. The DNS server returns a hostname, e.g., mail.example.org. MTA 110 queries a DNS server (not shown) for the A record of mail.example.org, e.g., the IP address. The DNS server returns an IP address of, for example, 127.118.10.3.5. MTA 110 opens an SMTP connection to the remote mail server providing e-mail service for example.org which is also running MTA 106. The message is transmitted to MTA 106 from MTA 110 using the SMTP protocol over a TCP connection.
5. MTA 106 delivers Larry's message for Martha to the local delivery agent 112. Local delivery agent 112 appends the message to Martha's mailbox. For example, the message may be stored in (e.g., using a sample file path on a UNIX system): /var/spool/mail/martha.
6. Martha has her user agent 114 connect to her ISP. Martha's user agent 114 opens a POP3 (Post Office Protocol version 3, defined in RFC1725) connection with the POP3 (incoming mail) server 112. User agent 114 downloads Martha's new messages, including the message from Larry.
7. Martha reads Larry's message.
The MTA 110, which is responsible for queuing up messages and arranging for their distribution, is the workhorse component of electronic mail systems. The MTA "listens" for incoming e-mail messages on the SMTP port, which is generally port 25. When an e-mail message is detected, it handles the message according to configuration settings, that is, the settings chosen by the system administrator, in accordance with relevant standards such as Request for Comment documents (RFCs). Typically, the mail server or MTA must temporarily store incoming and outgoing messages in a queue, the "mail queue." Actual queue size is highly dependent on one's system resources and daily volumes.
In some instances, referring to FIG. 2, communication between a sending host (client) and a receiving host (server), could involve relaying. In addition to one MTA at the sender site and one at the receiving site, other MTAs, acting as client or server, can relay the electronic mail across the network. This scenario of communication between the sender and the receiver can be accomplished through the use of a digital message gateway, which is a relay MTA that can receive digital messages prepared by a protocol other than SMTP and transform it to the SMTP format before sending it. The digital message gateway can also receive digital messages in the SMTP format, change it to another format, and then send it to the MTA of the client that does not use the TCP/IP protocol suite. In various implementations, there is the capability to exchange mail between the TCP/IP SMTP mailing system and the locally used mailing systems. These applications are called digital message gateways or mail bridges. Sending digital messages (e.g., e-mail) through a digital message gateway may alter the end-to-end delivery specification, because SMTP will only guarantee delivery to the mail-gateway host, not to the real destination host, which is located beyond the TCP/IP network. When a digital message gateway is used, the SMTP end-to-end transmission is host-to-gateway, gateway-to-host or gateway-to-gateway; the behavior beyond the gateway is not defined by SMTP.
While functional, existing digital message sending systems, such as MTAs, are unsatisfactory. Digital messages (e.g., e-mail) sent to a given domain (e.g., a particular ISP) or site may be blocked. However, typically, the blocking domain will either not specify why the digital message was blocked or will provide incomplete information as to why the message was blocked. In one example, the reason why a domain will block incoming digital messages is that a digital message quota, where the quota is based for example on a number of allowed digital messages per unit of time (e.g., per day, per week, per month) from the sending domain has been exceeded. However, the conventional sending digital messaging sending system (e.g., MTA 110 of FIG. 1) does not learn that a quota has been exceeded from the message failure notices that are returned to the sending MTA by the blocking domain. So the digital message sending system continues to resend the blocked digital messages and send any new additional digital messages (e.g., e-mail, text messages, etc.) in its queue to the blocking domain even though there is no chance that the blocking domain will accept the resent digital messages or the new digital messages from the digital message sending system because the quota has been exceeded. In another example, the receiving domain may be down because of equipment failure or scheduled maintenance. The digital message sending system may send digital messages to the receiving domain and meet with failure. But the digital message sending system will continue to resend the digital message and any new digital message in its queue to the receiving domain on some predetermined retry basis without intelligently backing off from its efforts to send out the digital message to the domain that is down.
Given the above background, what is needed in the art are improved systems and methods for sending out digital message to domains using, for example, MTAs or other forms of digital message sending systems that communicate digital messages to end users.
Discussion or citation of a reference herein will not be construed as an admission that such reference is prior to the present invention.

Systems and methods for adaptive communication control


When a user who shares content is selected in a first information communication apparatus used by one of the users who share content, sharing space securement information for the selected user is generated and transmitted to the server. When sharing space connection information for accessing a sharing space, which is generated by the server based on the sharing space securement information, is received by the first information communication apparatus, the sharing space connection information transmitted to the second information communication apparatus used by the user who share the content.

In recent years, with the popularization of mobile terminals such as digital cameras and smart phones, and the advancement of: social networking services (SNS) such as mixi (registered trademark), Facebook (registered trademark), and Flickr (registered trademark); and other content sharing services, users have more opportunities of easily capturing content such as pictures and videos, and of sharing them for fun.

Content sharing system, information communication apparatus, content sharing method, and communication method

PANASONIC INTELLECTUAL PROPERTY CORPORATION OF AMERICA


There is provided a method of computing a likelihood of malignancy in a mammographic image, comprising: receiving a single channel 2D mammographic image including a single pixel intensity value for each pixel thereof, converting the single channel 2D mammographic image into a multi channel 2D mammographic image including multiple pixel intensity value channels for each pixel thereof, computing by a first sub-classifier according to the whole multi channel image, a first score indicative of likelihood of malignancy within the whole multi channel image, computing by a second sub-classifier according to each respective patch extracted from the multi channel image, a respective second score indicative of likelihood of malignancy within each respective patch, and computing by a gating sub-classifier according to the first score and the second scores, an indication of likelihood of malignancy and a location of the malignancy.

The present invention, in some embodiments thereof, relates to mammographic image processing and, more specifically, but not exclusively, to systems and methods for automated detection of malignancy in a mammographic image.
Breast cancer is the most prevalent malignancy in the US and the third highest cause of cancer-related mortality worldwide. In the US over 230,000 new diagnoses and approximately 40,000 deaths occur annually, for example, as described with reference to American Cancer Society, "Cancer Facts & Figures 2015," Cancer Facts Fig. 2015, pp. 1-9, 2015. Regular mammography screening has been attributed with doubling the rate of early cancer detection and has been credited with decreasing breast cancer mortality by up to 30% over the past three decades, for example, as described with reference to B. Lauby-Secretan, C. Scoccianti, D. Loomis, L. Benbrahim-Tallaa, V. Bouvard, F. Bianchini, and K. Straif, "Breast-cancer screening—viewpoint of the IARC Working Group.," N. Engl. J. Med., vol. 372, no. 24, pp. 2353-8, 2015, and A. M. Kavanagh, G. G. Giles, H. Mitchell, and J. N. Cawson, "The sensitivity, specificity, and positive predictive value of screening mammography and symptomatic status.," J. Med. Screen., vol. 7, no. 2, pp. 105-10, 2000. Yet estimates of mammographic accuracy in the hands of experienced radiologists remains suboptimal with sensitivity ranging from 62-87% and specificity from 75-91% for example, as described with reference to A. M. Kavanagh, G. G. Giles, H. Mitchell, and J. N. Cawson, "The sensitivity, specificity, and positive predictive value of screening mammography and symptomatic status.," J. Med. Screen., vol. 7, no. 2, pp. 105-10, 2000, C. D. Lehman, R. D. Wellman, D. S. M. Buist, K. Kerlikowske, A. N. A. Tosteson, D. L. Miglioretti, and Breast Cancer Surveillance Consortium, "Diagnostic Accuracy of Digital Screening Mammography With and Without Computer-Aided Detection.," JAMA Intern. Med., vol. 175, no. 11, pp. 1828-37, November 2015, N. S. Winkler, S. Raza, M. Mackesy, and R. L. Birdwell, "Breast density: clinical implications and assessment methods.," Radiographics, vol. 35, no. 2, pp. 316-24, 2015, T. M. Kolb, J. Lichy, and J. H. Newhouse, "Comparison of the Performance of Screening Mammography, Physical Examination, and Breast US and Evaluation of Factors that Influence Them: An Analysis of 27,825 Patient Evaluations," Radiology, vol. 225, no. 1, pp. 165-175, October 2002, and K. Kerlikowske, R. A. Hubbard, D. L. Miglioretti, B. M. Geller, B. C. Yankaskas, C. D. Lehman, S. H. Taplin, and E. A. Sickles, "Comparative effectiveness of digital versus film-screen mammography in community practice in the United States: A cohort study," Ann. Intern. Med., vol. 155, no. 8, pp. 493-502, 2011.

This patent is subject to a terminal disclaimer.

Systems and methods for automated detection of an indication of malignancy in a mammographic image


A reinforced structural member has a channel-shaped laminate structure of a metal stamping, a channel-shaped foil and an intervening layer of structural foam. The reinforced structural member is formed by pressing a foil/resin preform into a channel and thermally expanding the resin to form a structural foam.

In a number of applications, light-weight, high-strength structural members are required, for example in motor vehicles and aircraft as well as in various devices such as home appliances and the like. A number of composite materials have been proposed in the past as structural members, such as exotic light-weight alloys. In most applications, however, mass reduction must be balanced against the cost of the product to the consumer. Thus, there is a need for providing strength without significantly increasing materials and labor costs. Moreover, reinforcement techniques are needed which can be adapted to existing geometries of structural parts, obviating any requirement for fundamental design changes.
As examples of reinforcement techniques, the present inventor has disclosed a number of metal/plastic composite structures for use in reinforcing motor vehicles components. In U.S. Pat. No. 4,901,500, entitled "Lightweight Composite Beam," a reinforcing beam for a vehicle door is disclosed which comprises an open channel-shaped metal member having a longitudinal cavity which is filled with a thermoset or thermoplastic resin-based material. In U.S. Pat. No. 4,908,930, entitled, "Method of Making a Torsion Bar," a hollow torsion bar reinforced by a mixture of resin with filler is described. The tube is cut to length and charged with a resin-based material.
In U.S. Pat. No. 4,751,249, entitled, "Reinforcement Insert for a Structural Member with Method of Making and Using the Same," a precast reinforcement insert for structural members is provided which is formed of a plurality of pellets containing a thermoset resin with a blowing agent. The precast member is expanded and cured in place in the structural member. In U.S. Pat. No. 4,978, 562, entitled, "Composite Tubular Door Beam Reinforced with a Syntactic Foam Core Localized at the Mid Span of the Tube," a composite door beam is described which has a resin-based core that occupies not more than one-third of the bore of a metal tube.
In co-pending U.S. patent application Ser. No. 08/245,798, filed May 19, 1994, entitled "Composite Laminate Beam for Automotive Body Construction," a hollow laminate beam characterized by high stiffness-to-mass ratio and having an outer portion which is separated from an inner tube by a thin layer of structural foam is described. In co-pending U.S. patent application Ser. No. 08/245,798, filed May 19, 1994 now U.S. Pat. No. 5,575,526, entitled "Composite Laminate Beam for Automotive Body Construction," a W-shaped carrier insert reinforcement which carries a foam body is described for use in reinforcing a hollow beam.
In copending U.S. patent application Ser. No. 08/644,389, filed May 10, 1996, entitled "INTERNAL REINFORCEMENT FOR HOLLOW STRUCTURAL ELEMENTS," the present inventor discloses an I-beam reinforcement member which includes an external foam layer. The I-beam, as in the case of most of the foregoing reinforcements, involves a preformed structural insert which is then inserted into a hollow structural member.
It is also known to increase strength of a laminate structure by bonding together flat metal plates using an intervening layer of resin. For example, it is known to form a metal laminate sheet for use as a floor panel member which comprises a pair of flat metal sheets having an intervening layer of asphalt or elastic polymer.
Although filling the entirety of a section with plastic foam does significantly increase section stiffness (at least when high-density foams are utilized), this technique also may significantly increase mass and thus part weight, which, as stated, is an undesirable feature in most applications. In addition, filling a section entirely with foam may be prohibitively expensive and creates a large heat sink. And, although increasing the metal gauge of a section or adding localized metal reinforcements will increase stiffness, as the metal thickness increases, it is more difficult to form the part due to limitations of metal forming machines.
Accordingly, it would be desirable to provide a low-cost technique for reinforcing a channel-shaped structural member without proportionately increasing the mass. It would also be desirable to provide a method of reinforcing an existing channel-shaped member which does not require any fundamental design changes to the member. The present invention provides channel-shaped members which have increased strength with moderate increases in mass and without the use of high volumes of expensive resins. The present invention further provides a method for reinforcing existing structural parts without redesigning the geometry of the part. It has been found that the present invention increases section stiffness and provides vibration dampening in channel-shaped sections in a highly efficient and reproducible manner.

Reinforced channel-shaped structural member


The hardness and appearance of an in-mold coating for a molded article of cured unsaturated polyester are improved by the addition of melamine and/or benzoguanamine to an unsaturated polyester powder coating composition and subjecting the modified powder coating to a molding temperature of from about 260.degree. F. to about 340.degree. F. and a pressure of from about 650 psi to about 2,000 psi for from 1 to 12 minutes. From about 5 to about 40 parts of the melamine and/or benzoguanamine per hundred parts by weight of the coating resin is used.

In-mold coating is a known technique for decorating or priming the surface of an article formed in a matched die mold under heat and pressure. A coating powder, which can be an unsaturated polyester formulation, is applied electrostatically to the interior wall of the mold. The powder melts and coalesces on the hot mold surface to produce a uniform coating. The fill resin, which constitutes the bulk of the finished article, is then inserted in the mold and heat and pressure is applied. When the cures of the coating and fill resin have advanced sufficiently and said resins are integral, the mold is opened and the molding is removed. It has been found desirable that the coating and fill resins be cross-linked across the interface between them to maximize the adhesion of one to the other.
The following patents relate to in-mold coating techniques of the type used in this invention:

In-mold coatings with improved performance


An actuator comprising a flexible substrate having a surface comprising one or more active regions, each of the active regions having disposed thereon an electrochemically active film comprising a plurality of 1T phase 2D MoS2 nanosheets which impart a first force upon the flexible substrate in response to electrochemical charging of ions in the 2D MoS2 nanosheets and impart a second force upon the flexible substrate in response to electrochemical discharging of ions in the 2D MoS2 nanosheets, wherein the first and second forces imparted to the flexible substrate each being sufficient to displace the flexible substrate. The flexible substrate may comprise a polymer substrate and the electrochemically active film may comprise a conductive layer having disposed thereon the plurality of 1T phase 2D MoS2 nanosheets.

Actuators that convert electrical energy to mechanical energy are useful in a wide variety of electromechanical systems and robotics. Actuation systems based on heating carbon nanotube electrodes or solvent adsorption/desorption, electrochemically induced carbon nanotube electrodes, graphite electrodes, polymer electrodes, and metals have been reported.
Electroactive polymers have also been studied for actuation over the past few decades, however the stress generation of polymers has remained low due to their low modulus in general, though mechanical performance as well as work density at low rates can be increased by incorporating CNTs into conjugated polymers. Recent studies with Au—Pt nanoporous metals have revealed exceptionally high strains, but such high strains were achieved at relatively low frequencies (0.00025 Hz) and such actuator materials are expensive. The use of abundant materials such as metallic NiOOH and V2O5 fibers can mitigate the cost of metallic actuators, though the actuation performance of NiOOH and V2O5 actuators depends on the crystallographic orientation of the material.

Metallic molybdenum disulfide nanosheets-based electrochemical actuators

RUTGERS, THE STATE UNIVERSITY OF NEW JERSEY


A method and an apparatus analyze a computer program for dependencies of the program output on the program input. To analyze the program, the program is transformed by a function into a Boolean expression called a verification condition. An example of this function is the weakest liberal precondition. The verification condition characterizes a condition between the input and the output of the program that must be satisfied for the output to be independent of the input. A theorem prover evaluates the verification condition to determine whether the output would depend on the input if the program was executed. If the verification condition evaluates to true, then the output is independent of the input; false, then the output depends on the input.

In computer systems, and particularly networked computer systems, it is common for a first computer system to download and execute a program from a second computer system. During its execution, the program might access private data of the first computer. Generally, the first computer might permit the program to read and write such private data. Moreover, the first computer might permit the program to read and send public data back to the second computer. The first computer, however, wants to ensure that the program does not send private data back to the second computer along with the public data. So, the program must have a secure information flow, that is, the behavior of the program must not reveal anything about the private data of the first computer, either by the public data that is returned to the second computer or by not returning the public data at all.
Consequently, the problem of determining whether the information flow of a program is secure has given rise to two general approaches at a solution, type systems and data flow analyses. Type systems associate a type or a security level with each expression and statement in the program. Some statements may not type check: for example an assignment statement "x:=E", which assigns the value of expression E to variable x, type checks only if the type of expression E is less than or equal to the type of variable x (i.e., type(E).ltoreq.type(x)). For a program to be secure, every statement must type check.
The data flow analysis approach analyzes the data flow of a program using standard compiler techniques. For example, the program "v:=v+h; v:=0", where h is a private variable, and v is a public variable, is transformed into another program with a variable vv denoting the set of variables that may contribute to the value of the variable v and with a variable hh denoting the set of variables that may contribute to the value of the variable h. The exemplary program becomes "vv:=vv.orgate.hh; vv:={ }", where ".orgate." denotes set union and "{ }" denotes the empty set. Standard compiler techniques then infer that the program ends with "vv is { }", which means that the final value of v does not depend upon any other variables, especially not upon the value of h. Hence, the data flow analysis will certify this program.
Both the type system and data flow analyses approaches have been proven sound; that is, these methods do not give false positives. Therefore, a program certified as secure is truly secure. Both approaches, however, are too coarse and reject too many programs that are actually secure, i.e., they produce too many false negatives. Known type systems, for instance, will reject any program with an insecure sub-component and thus produce a false negative. For example, the type system method will incorrectly reject the program "v:=h; v:=0" because of the "v:=h" sub-component, even though the final value of v does not depend on h. The data flow analysis approach will reject some secure programs because the approach does not detect that a particular operator in the program will make the final value of v independent of the value of h. For example, the data flow method will reject the secure program "v:=h; v:=v-h", although the program always terminates with v=0.
Hence, a more fine grained method and apparatus are needed that can properly certify programs with secure information flow that previous implementations reject.

Method and apparatus for statically analyzing a computer program for data dependencies


A stand for scooters includes a base laterally mounted to a longitudinal frame under a platform of the scooter. A supporting shaft has a first end pivotally mounted to the base and a second end selectively abutting against a support surface/ground for supporting the scooter. A spring plate has two opposite ends respectively engaged to two opposite ends of the base. The wiggle range of the supporting shaft is 180 degrees and temporarily positioned in each 90 degrees due to a restitution force and a shape of the spring plate.

1. Field of the Invention
The present invention relates to a stand, and more particularly to a stand for support a scooter after the scooter being used.
2. Description of Related Art
A scooter has been a popular toy for several years. The scooter has only two wheels such as a stand is necessary for supporting the scooter after being used. The conventional stand for the scooter usually uses a spring as a restitution/holding element. However, the spring may hook user's shoestring or bottom of a trouser leg. It is very dangerous and inconvenient during operating the scooter. In addition, the stand has a safety to prevent the stand from being suddenly backward moved. However, the user may fall from the scooter during riding when the downward extending stand abuts against the ground and spoils the balance of the moving scooter.
The present invention has arisen to mitigate and/or obviate the disadvantages of the conventional stand for scooters.


A plastic building element is described which permits a variety of play structures to be assembled. The main building element is a dish-shaped molded plastic part, having a bottom, integral lower side walls projecting generally upwardly from the outer periphery of the bottom to define a lower portion of one nominal diameter, integral generally horizontal portions projecting outwardly from the top of the lower side walls, and integral upper side walls projecting generally upwardly from the outer periphery of the horizontal portion to define an upper portion having a substantially larger nominal diameter. Preferably, the side walls are defined by a number of generally rectangular panels defining a polygonal shape for the building element as viewed in horizontal section. In the preferred embodiment, the structure is hexagonal. The building element can be used in its simplest application as a children's sandbox, or assembled to define play cavities in the form of more elaborate structures such as a "spaceship" or a "gumball machine".

This invention relates to play structures, and particularly to such structures which provide a semi-enclosed play area for children.
Many forms of play structures are of course already known. For example, tree houses and children's play houses of various designs are known, most being made from wood, either custom made or else fabricated from kits. Some plastic structures are also known. Play houses constructed from rotationally molded plastic panels which are fastened together are marketed by Fisher-Price, for example.


Disclosed is an optical device which combines a controlled level of attenuation, a high degree of wavelength insensitivity and a substantial decrease in modal interference problems. The optical device has a core having a core diameter and a core refractive index; an inner cladding having an inner cladding outer diameter less than ten times the core diameter and a refractive index less that the core refractive index; and an outer cladding having a refractive index higher that the inner cladding refractive index. At least one part of the core, the inner cladding or the outer cladding is doped with at least one absorbing element. Preferably, the core is doped with cobalt in an appropriate concentration, providing the same degree of attenuation at 1310 nm and 1550 nm, while also considerably reducing modal interference. The optical device can be used as an attenuator between a transmission fiber and a detection fiber or can be used to couple a transmission fiber directly to a detector.

The present invention relates to optical fiber attenuators for attenuation of optical signal communications and for the reduction of modal interference in such optical fiber attenuators.
It is common knowledge in the art that an optical fiber doped with transition metal elements will exhibit a high transmission loss. A method of incorporating a transition metal element in a glass body produced by the flame hydrolysis technique is described in U.S. Pat. No. 3,859,073 to SCHULTZ.
Also known in the art is the optical absorption of the transition metal elements in vitreous silica, as described by Peter C. SCHULTZ in xe2x80x9cOptical Absorption of the Transition Elements in Vitreous Silicaxe2x80x9d, J. Am. Ceram. Soc., Vol. 57, No. 7, pp. 309-313, 1974.
Knowledge of this has permitted the manufacture of high-attenuation fibers. These high-attenuation fibers can be tailored to produce a controlled level of attenuation with a high degree of wavelength insensitivity, by properly selecting the material used as a dopant, the dopant concentration and the length of the attenuation fiber.
A high-attenuation fiber is used to produce optical fiber attenuators which can be inserted in optical transmission systems to attenuate the amount of optical power present in a fiber link. The most common use for a high attenuation fiber is to either attenuate the detected optical signal level down to a receiver""s optimum detection sensitivity, or to act as a reflection-less terminator at the end of unused fibers. Examples of high attenuation fibers, and methods for making the same are described in U.S. Pat. No. 4,881,793 (Tarbox); U.S. Pat. No. 5,572,618 (DiGiovanni et al.); and U.S. Pat. No. 5,633,974 (Chia). Essentially, these high-attenuation fibers are made of a single-mode fiber, where the core is doped with, usually, a transition metal in order to increase the absorption in the core.
The high-attenuation fibers are usually a few centimeters long and are provided with connectors at each end to facilitate connection to a low-loss optical fiber. The fabrication of the high-attenuation fiber connectors implies the assembly of the high-attenuation fiber secured in a connector ferrule of precise diameter. The high-attenuation fiber is thus usually connected between the output end connector of a transmission fiber and the input end connector of a detection fiber.
The tolerance on standard fiber diameters is usually less than xc2x11 micron and the core-cladding concentricity is better than 1 micron. Also, the tolerance on the ferrule hole diameter is usually better than xc2x10.5 micron. Generally, a fiber with small diameter will be off-centered in the ferrule of bigger hole diameter. Thus, two connectors made with the same (or different) fibers, will usually exhibit offset-induced losses when they are connected together.
This phenomenon is known in the art and may cause modal interference. It has been found that when a short piece of single-mode fiber is connected between a transmission fiber and a detection fiber, most of the optical power of the fundamental mode of the transmission fiber is coupled into the fundamental mode of the short piece of fiber. However, because of the small discontinuity due to the misalignment of the joint, some of the power of the fundamental mode of the transmission fiber is coupled into higher-order modes of the short piece of fiber. The fundamental mode and the higher-order modes propagate along the short fiber piece with different propagation delays and reach the junction of the short fiber piece and the detection fiber out of phase. Again, most of the optical power of the fundamental mode of the short fiber piece is coupled into the fundamental mode of the detection fiber. Also, because of a misaligned joint, some of the optical power of the higher-order modes of the short piece of fiber is coupled into the fundamental mode of the detection fiber, where it interferes with the optical power coupled from the fundamental mode of the short piece of fiber. The out-of-phase component varies with wavelength and results in an interference effect that can be observed as an oscillation in the detected signal from the detection fiber measured as a function of wavelength. For a greater discussion on modal interference, see S. HECKMANN, xe2x80x9cModal Noise in Single-Mode Fibres Operated Slightly Above Cutoffxe2x80x9d, Elect. Let., Vol. 17, No. 14, pp. 499-500, 1981, and K. ABE, Y. LACROIX, L. BONNELL and Z. JAKUBCZYK, xe2x80x9cModal Interference in a Short Fiber Section: Fiber Length, Splice Loss, Cutoff and Wavelength Dependencesxe2x80x9d, J. Light. Technol., Vol. 10, No. 4, pp. 401-406, 1992.
Modal interference is practically unpredictable and is of great concern to the optical fiber systems designers. The common solution to the modal interference problem is to use at least a one meter long fiber piece after each discontinuity (connector or splice) to eliminate the optical power coupled into the higher-order modes. Other solutions have been proposed with a special fiber design to control modal noise in short fiber sections. One such design includes an outer cladding layer that has a high refractive index and a high attenuation (see for example U.S. Pat. No. 4,877,306 to KAR). The outer cladding effectively traps higher-order modes. Another proposed solution has been to use doubly clad optical fibers with a low-index inner cladding. Such a fiber is usually referred to as a W-type fiber. This type of fiber increases the transmission loss of the higher-order modes and encourages leakage of such higher-order modes in the outer cladding. For a detailed discussion on the propagation in doubly-clad single mode fibers, see M. MONERIE, xe2x80x9cPropagation in Doubly Clad Single-Mode Fibersxe2x80x9d, IEEE J. Quantum Electronics, Vol. QE-18, No. 4, pp. 535-542, 1982 and S. KAWAKAMI and S. NISHIDA, xe2x80x9cPerturbation Theory of a Doubly Clad Optical Fiber with a Low-index Inner Claddingxe2x80x9d, IEEE J. Quantum Electronics, Vol. QE-11, No. 4, pp. 130-138, 1975.
An example of the use of this design can be found in U.S. Pat. No. 5,241,613 (Li et al.), in order to reduce modal interference.
However, to Applicant""s knowledge, no fiber design has been proposed which attenuates the fundamental mode and reduces modal interference in the same device of relatively small length.
It is thus an object of the invention to provide an optical attenuating element which also reduces modal interference, and more specifically, an optical device which combines a controlled level of attenuation, a high degree of wavelength insensitivity and a substantial decrease in modal interference problems. In accordance with the invention, this object is achieved with an optical attenuating element for attenuating and eliminating modal interference comprising a core having a core diameter and a core refractive index; an inner cladding having an inner cladding outer diameter less than ten times the core diameter and a refractive index less than the core refractive index; and an outer cladding having a refractive index higher than the inner cladding refractive index; where at least one part of at least one of said core, said inner cladding and said outer cladding is doped with at least one absorbing element.

High-attenuation fiber with cladding mode suppression for all-fiber optical attenuator


A method for the division of single crystals, in particular of GaAs, is provided in which a single crystal (1) to be cut into at least two parts and a cutting tool (2, 3; 8, 8a, 8b, 8c) are moved relative to one another in a direction of advancement (V) and wherein the single crystal (1) is oriented in such a way that a specified crystallographic orientation (K) lies in the cutting plane (T), characterized in that an angle (ρ) between the specified crystallographic direction (K) and the direction of advancement (V) is chosen in such a way that forces which act on the cutting tool during cutting in a direction at right angles to the cutting plane compensate one another.

(1) Field of the Invention
The invention relates to a method and a device for the division of single crystals, an adjusting device and a test method for the determination of an orientation of a single crystal for such a method.
(2) Description of Related Art
Single crystals produced by crystal pulling are divided into individual disks known as wafers for use in semiconductor technology. Known cutting methods are inner hole sawing and wire cutting. The cutting forces occurring in the division of single crystals result in lateral deflection of the rotary cutting disk in the case of inner hole sawing or of the wire in the case of wire cutting. As a result of this wafers of nonuniform thickness are produced or the surface exhibits other irregularities, e.g., warp and bow. In the case of silicon single crystals the predominant problem occurring is corrugation of the surface. This results in a reduction in quality in the wafers produced and hence in a lower yield of high-quality wafers.
To solve this problem it is known in the case of inner hole sawing to measure the deflection of the cutting disk and to correct this by the action of compressed air. This method, however, has the disadvantage that a film of coolant applied for cooling the cutting disk is affected by the compressed air and this in turn has an effect on cooling during cutting. It is, furthermore, known to set the single crystal in a mounting which is specially shaped in order to counteract the forces occurring in the deflection of the cutting disk with opposing forces for compensation. In wire cutting no active influence on the deflection of the wire is possible.

Method and device for cutting single crystals, in addition to an adjusting device and a test method for determining a crystal orientation


A data communication network may include two or more master clocks, and a synchronization system connected to the master clocks. The synchronization system may determine a time-base for the master clocks. The synchronization system may control the master clocks according to the determined time-base. The data communication network may include one or more slave clocks. The slave clocks may be controlled by a slave clock time-base controller based on time information of a single selected master clock selected from the master clocks.

In communication networks, such as computer networks or other data communication networks, accurate timing is often required, for example to facilitate event synchronization and data correlation. Typically, the nodes in the network include an internal clock which provides a local time-base. In theory, if two internal clocks are initially set to a common time-base and their frequency sources are running at exactly the same rate, they would remain synchronized. In practice, however, clocks are set with limited precision, frequency sources run at different rates due to initial manufacturing tolerance, changes in temperature or pressure, and aging. Because of these inherent instabilities, a repeated synchronization may be used to maintain a correspondence between the local time-bases of the nodes in the network.
To set the nodes in the network to a common time-base, so called 'master-slave synchronisation' is known. In a master-slave synchronisation system, the nodes are connected to a common source. The common source provides a common time-base to the nodes, and hence operates as a master, whereas the nodes set their internal time-base to the received common time-base and hence act as slaves. However, a disadvantage of such a synchronisation is that in case the common source fails, the nodes will not be synchronised.
For example, International Patent Application WO 2005/119951 discloses a method for establishing a global time base in a timed communications system comprising several subscribers. One of the subscribers of the communications system is defined as the time master, with which the remaining subscribers are synchronised. One or more additional subscribers are defined as a substitute time master. Firstly, an attempt is made to synchronise all subscribers of the communications system with the primary time master. If the attempt fails, a next respective substitute time master in a predetermined sequence is selected and an attempt is made to synchronise all subscribers of the communications system with the selected substitute time master. However, a disadvantage of this master system is that while the synchronisation to the primary time master or the substitute time master may succeed, an error in the time base provided by the master will cause a malfunction of the timing in the network.
United States Patent Application Publication US 2005/005469 discloses a network with a master-slave configuration. Timers of a plurality of slave units are synchronized with a timer of the master unit. The network includes a middle hierarchical plane of units which act as slaves for the master unit, and are hence synchronised to the master unit, and as masters for the slave units. The slaves units are synchronised to the timer of a respective unit in this middle hierarchical plane to which they are connected, and hence indirectly to the master unit. However, a disadvantage of the system disclosed in this document is that in case the master unit fails, the entire timing in the network fails.
ERIKSON C ET AL: "A communication protocol for hard and soft real-time systems", REAL-TIME SYSTEMS, 1996, PROCEEDINGS OF THE EIGHTH EUROMICRO WORKSHOP ON L'AQUILA, ITALY 12-14 Jun. 1996, LOS ALAMITOS, Calif., USA, IEEE COMPUT. SOC, US, 12 Jun. 1996, pages 187-192, discloses a data communication system with a rotating master unit, that is during a first period of time a first unit acts as a master for the nodes in the system and during a second period of time succeeding the first period of time, a second acts as a master for the nodes in the system. However, a disadvantage of the system disclosed in this document is that in case the unit acting as master for the respective period of time fails, the entire timing in the network fails.
Accordingly, a common disadvantage of the prior art systems described above is that in case the master unit fails, the nodes will not be synchronised.
As an alternative to the master-slave synchronisation, so called 'distributed synchronisation' is known, for example from U.S. Pat. No. 5,694,542. In a network with distributed synchronisation, the nodes exchange timing information. Each node determines a time-base from the timing information received from the other nodes and adjusts its internal clock to the determined time-base. However, distributed synchronisation requires complex algorithms to determine the time-base. Furthermore, each node requires a synchronisation unit which can determine the time-base. Accordingly, a disadvantage of distributed synchronisation is that it is complex and requires a large amount of resources.

Network and method for setting a time-base of a node in the network


A link bracelet includes two rows of side links forming the edges of the bracelet and at least one row of central links arranged between the side links, wherein the side links each include at least two through holes in the inner face thereof facing the central links and the central links are traversed by at least two housings. The bracelet includes arbors inserted into each of the holes in the side links, the head of the arbors being fitted into the housings of the central links and each having a grooved portion in proximity to the end thereof, and the central links include an opening giving access to the grooved portions, which are arranged to cooperate with a locking member designed to be inserted into the openings in the central links to maintain the assembly of the bracelet.

Such a bracelet is known from FR Patent No. 2688984 which discloses a bracelet with links assembled by means of free pins, whose ends have grooves cooperating with housings of locking members designed to be fixed, in the service position, inside a recess provided in the outer links, which recess opens on the inner side face of these links. These locking members are secured in the outer links by means of screws.
There is also known from EP Patent No. 1186252, a link bracelet which includes two rows of side links and at least one row of central links arranged between the side links, and pins freely arranged in the side and central links but without play. The pins comprise at each end thereof a groove arranged to cooperate with locking members intended to be clipped into recesses formed in the side links in order to maintain the assembly.
Link bracelets of this type have drawbacks relating to the insertion and/or removal of the locking members with respect to the outer links.
Indeed, the insertion and/or removal requires the use of a tool, such as a screwdriver, to assemble and/or disassemble the bracelet or to adjust the bracelet length.
Finally, the reliability of the assembly is not certain in the case of clip-in locking members; the latter may no longer provide sufficient hold over time, or break, or even be partially dislodged in case of shock.


A circuit and method for boosting bitline performance uses a bitline booster circuit to allow long bitlines, with large numbers of memory cells attached, to discharge to a digital zero in a faster time. One bitline booster circuit requires only two additional NOR gates, two additional transistors, and one additional control signal. Consequently, the bitline booster circuit does not require a significant number of added components, does not require multiple control signals and takes up minimal additional silicon area.

Electronic components and devices, such as microprocessors and other various integrated circuits, have advanced in many significant ways. As one example, feature sizes have moved into the sub-micron range thereby allowing larger numbers of transistors to be formed on a given silicon surface area. This, in turn, has resulted in greater device and circuit density on the individual chips. As another example, in part due to the first advance discussed above, microprocessors have increased dramatically in clock speed. At present, microprocessor speeds of 2.5 Gigahertz are coming to market and the 3 and 4 Gigahertz range is rapidly being approached.
Because of the advances in device density and microprocessor speed discussed above, it is now important to minimize any potential delays in the processing of information and to recognize that existing circuits that once operated within tolerable margins may, at the higher clock speeds of newer systems, become the limiting factor in microprocessor performance.
One example where higher clock speeds have made prior art circuits and methods inadequate is in the area of memory arrays and, in particular, on-chip memory arrays in microprocessors. FIG. 1 shows a typical prior art memory array 100 including: write amplifier block 101; write column switch 103; bitline pre-charge circuit 105 and memory cells 110, 120, and 130 coupled between bitline pair 107 and 109.
The structure and operation of prior art memory arrays, such as prior art memory array 100, is well known to those of skill in the art and is therefore not discussed in more detail herein to avoid detracting from the present invention.
As shown in FIG. 1, and as is also well known to those of skill in the art, each of memory cells 110, 120, and 130 of prior art memory array 100 included an inherent parasitic capacitance, and bitlines 107 and 109 also include an inherent parasitic capacitance and an inherent resistance. These parasitic capacitances and resistances are shown in FIG. 1 symbolically as parasitic capacitors 111, 115, 121, and 125 and resistors 113, 117, 123 and 127.
A pair of parasitic capacitances, such as capacitors 111, 115, associated with memory cell 110 and bitlines 107 and 109, and an inherent resistance, such as resistors 113, 117, also associated with memory cell 110 and bitlines 107 and 109, are an unavoidable component of each memory cell added to bitline pair 107/109. Consequently, the more memory cells, such as memory cells 110, 120 and 130, that are coupled to bitline pair 107/109, the greater the cumulative parasitic capacitance and resistance there is at end 150 of bitline pair 107/109.
Unfortunately, modern electronic devices are typically requiring larger and higher density memory designs. Consequently, there can be a requirement to increase the number of memory cells connected to a bitline in order to keep a balance between wordline and bitline loads. In addition, to meet a given aspect ratio of a memory array, a designer may need more memory cells to be connected to a bitline. As a result, very long or "tall" bitlines that are very heavily loaded for parasitic resistance and capacitance result.
As noted above, this becomes a problem because, for example, during a write operation, the switching rate of the heavily RC loaded bitlines will be very low, and, as a result, the end of the bitlines, such as end 150 of bitline pair 107/109, may not have time to discharge to a value very close to zero, also called a digital zero or "ground" in the time allotted by the system clock before the next operation. It is important that the bitline discharge to this value very close to zero to ensure that there is enough margin to write to the memory array at the given frequency. As a result, the speed of operation of the memory array, and the entire system, is often slowed down. Of course, as the speed of system clocks increases, this problem becomes even more pronounced as there is even less time between operations for a bitline to discharge from a pre-charged value. In addition, as more and more memory is moved into "on chip" caches, the problem becomes even more immediate and more pronounced because these on-chip memory arrays are expected to operate at even higher speeds than off-chip designs.
To overcome the problems described above with respect to prior art memory array 100, a designer could try adding a an additional write driver, such as write drive block 101 in FIG. 1, in association with additional write column switch 103, to end 150 of prior art memory array 100. This action would effectively cut the number of memory cells on a bitline/bitline pair in half. However, this solution requires more components, uses more precious silicon space and often complicates the design by adding more control signals, routing metal, and synchronization issues. Another method would be to increase the width of bitlines 107 and 109. However, this "solution" would also use more silicon space and would add even more parasitic capacitance to bitlines 107 and 109.
As noted, in the prior art, there were typically fewer memory cells per bitline, the system clock speeds were slower and memory arrays were typically off-chip. However, with the advances discussed above regarding clock speeds and the ability to put more memory on-chip, the prior art memory arrays and methods are rapidly proving inadequate to need the needs of modern electronic systems and devices.
What is needed is a circuit and method for boosting bitline performance that allows long bitlines, with large numbers of memory cells attached, to discharge to a digital zero in a faster time and does not require a significant number of added components, does not require multiple control signals, and takes up minimal additional silicon area.


Metal layers of a smartcard may be provided with slits overlapping at least a portion of a module antenna in an associated transponder chip module disposed in the smartcard so that the metal layer functions as a coupling frame. One or more metal layers may be pre-laminated with plastic layers to form a metal core or clad subassembly for a smartcard, and outer printed and/or overlay plastic layers may be laminated to the front and/or back of the metal core. Front and back overlays may be provided. Pre-laminated metal layers having an array of card sites, with each position having a defined area prepared for the later implanting of a transponder chip module characterized by different sized perforations and gaps around this defined area adjacent to the RFID slit(s), to facilitate the quick removal of the metal in creating a pocket to accept a transponder chip module.

Digital offset printing presses use an offset cylinder to transfer a color image to a paper, film or metal substrate. These presses are based on an electro-photographic process where an electrostatic image is formed on a surface of a charged photo-conductor by exposing the surface to a light and shadow image to dissipate the charge on areas of the photo-conductor surface exposed to the light. A charged electrostatic latent image is then developed using ink (liquid toner) containing an opposite charge to that on the electrostatic latent image. The resulting electrostatic toner image is then transferred to a hot blanket, where the toner is coalesced and maintained in a tacky state until it is transferred to the substrate, which cools the ink and produces a tack-free print.
Conventional digital offset receiving sheets are typically highly cationic in nature, are not thermally stable at temperatures above 200 degree C.°, and commonly employ a substrate prepared using a polyamine or quaternary ammonium polymer.
Xerography is an electro-photographic technique that uses electrostatic charges, dry ink (toner) and a fusing process to produce and fix an image on a substrate. A negative of an image is beamed using a laser or light-emitting diodes (LEDs) onto a positively charged selenium-coated, photoconductive drum, thereby canceling the charge and leaving a positively charged copy of the original image. A negatively charged toner is attracted to the positive image on the drum. The toner is then attracted to the substrate (e.g., paper), which is also positively charged. Heat and/or pressure or light is then used to fuse the toner thereby causing it to permanently adhere to the substrate. Receiver sheets used in xerographic printers and presses utilizing heat and pressure fusing may be exposed to temperatures ranging from about 140° C. to about 250° C.
Conventional receiver sheets used in xerographic (dry toner) printers and presses typically employ uncharged substrates prepared from epoxy or acrylic resins, which are coated with charged polymeric coatings.
WO 2011036480 A1 describes a digital printing process for wood or metal. The printing process comprises the steps of: a) Applying a powder coating to at least one surface of the substrate to form a first layer of the substrate; b) Applying an ink composition to the substrate to form a second layer of the substrate; and c) Curing the substrate comprising the first and second layers.
It relates to a printing process for printing on a substrate. In particular, it relates to a printing process for digitally printing on a metal or wood-based substrate.
Optimizing Ink Receptiveness on PVC
Substrates require the right coating to anchor inks and digital print receptive coatings are available from various companies. Refer to
http://www.tekra.com/resources/tek-tip-white-paper/tek-tip-evolving-digital-card-market
http://www.michelman.com/Printing-%26-Packaging/Specialty-Printing/HP-Indigo-Solutions/
http://www.dkgroup.com/product-category/laminating-films/
Direct printing on plastic inlay sheets using a HP Indigo press is standard in the smartcard industry, avoiding the problem of shrinkage of the plastic layers.
The same technique can be applied to plastic metal hybrid smartcards, by digitally printing direct on a plastic-metal-plastic inlay having a suitable format such as 3×7.

Smart cards with metal layer(s) and methods of manufacture


An illuminated sign has a primary light source in spaced apart relation to a transparent or translucent substrate having quantum dot phosphors printed or coated thereon. The primary light source may be a blue LED, a white LED or an LED having a significant portion of its emission in the ultraviolet region of the spectrum. The LED may be a backlight for the transparent or translucent substrate and/or an edge light, a down light or an up light.

1. Field of the Invention
This invention relates to illuminated signs. More particularly, it relates to signs comprising photoluminescent quantum dots (QDs).
2. Description of the Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98
Illuminated Signage
Illuminated signage has applications in a wide variety of sectors, from road safety and warning or emergency signs to advertising boards and shop fronts. Illuminated signage may be made from a range of different lighting sources, and may comprise static or rolling displays. Conventional lighting displays traditionally utilize solid-state lighting. Color is an important aspect of signage, since it may be used to convey a message by association, e.g. red often signifies danger. The human eye is also more receptive to particular wavelengths of light than others; in normal light conditions the human eye is most sensitive to light around 555 nm, i.e. yellow-green, while in low-intensity light conditions the eye becomes more receptive to violet and blue light and less sensitive to green and red light. Thus, lighting systems that can provide a wide range of colors across the visible spectrum are advantageous.
Illuminated lighting may be static, flashing, or rolling, whereby a moving message is displayed. Particular lighting systems are often more suited to one display format than another, for instance liquid crystal displays, which have long switching times, are poorly suited for flashing signage. A sign may be "back-lit" whereby the illumination comes from behind the sign, "front-lit" where illumination is typically by swan neck lights shining on the front of the sign, or "edge-lit" where an opaque sign is indirectly illuminated by backlighting to give a halo effect.
Signage Applications
In many jurisdictions, legislation is in place having requirements for illuminated traffic and safety signage. For example, "The Traffic Signs Regulations and General Directions" legislation of 1994 stipulates that, in the UK, internally or externally illuminated signage is mandatory during the times that street lighting is in use or during the hours of darkness, on any road within 50 m of a lamp lit by electricity that acts as part of a system of street lighting. Exemptions apply for temporary signage; however this must be illuminated by retro-reflective material. Estimates from a US study suggest that replacing incandescent traffic signs with LEDs could reduce energy costs by 93%; with an installation cost estimated at $300 for replacing an incandescent bulb with LEDs, the annual energy saving calculated at 1,266 kWh could save $125 in energy ["Responsible Purchasing Guide: LED Exit Signs, Street Lights, and Traffic Signals", Responsible Purchasing Network, 2009]. Failure of incandescent bulbs and fluorescent lighting can be instantaneous, which in traffic sign applications may have potentially serious consequences. Therefore, alternative signage for which the failure is gradual (e.g. dimming over time) is desirable since it offers warning, allowing time for the signage to be replaced.
The "Health and Safety" legislation of 1996 requires that, in the UK, the light emitted from illuminated signs must produce a luminous contrast that is appropriate to its environment, such that there is no excessive glare from an excessive amount of light, or poor visibility as a result of insufficient light. Specific colors must be adhered to; red for prohibition, danger, and fire-fighting equipment signs, yellow/amber for warning signs, blue for mandatory signs, and green for emergency escapes, first aid signs, and to signify no danger. As with traffic signs, failure may have potentially hazardous consequences, thus an illumination system that decays gradually rather than instantly is advantageous.
Illumination may be applied to advertising boards to attract the attention of the observer. Advertising displays benefit from a lighting system that is easily adaptable, since advertisements are often temporary, thus a permanent back-lit system combined with a temporary fascia is often favorable. If the fascia is temporary, then a low-cost but quick manufacturing method is desirable, while display lifetime is less important.
Illuminated shop/business front signs may be used to attract the attention of passers-by and to make an entrance more visible during the hours of darkness. This is particularly effective for businesses that predominantly operate at night, such as bars, restaurants and nightclubs. The lighting displays may be required in any color, and are usually illuminated continuously for extended periods of time, thus a display that is inexpensive to power is desirable. Shop/business front signs are often large in size, therefore a technology without size restrictions is preferable.
Information signs, e.g. exit, toilets, "please pay here", etc. may be illuminated to enhance their visibility. Such signs are required in almost any color to suit the tastes and requirements of the consumer. The signs are likely to require continuous illumination for extended periods of time, therefore a reliable lighting system that is inexpensive to power is advantageous.
In total, illuminated signage makes considerable contribution to worldwide energy costs and CO2 emissions. By using more "green" illuminated signage technologies, such as the QD signage displays described herein, not only can energy and CO2 emissions be reduced, but also cost. With escalating energy costs, the initial investment cost of installation of QD signage displays can be recuperated by the energy savings, which for public funded signage could be favorable to the tax-payer. The current invention further provides a reliable illumination source, which decays gradually rather than failing instantly. The illuminated devices disclosed herein may be used to fabricate many different types of signage and are not restricted to the aforementioned applications.
Display Technologies
"Neon lighting" is often used to refer to gas discharge lighting tubes containing neon or other gases. The tubes contain a rarefied gas, across which a voltage is applied to liberate electrons from a tungsten cathode. The electrons collide, ionizing the gas inside the tube to form a plasma. Neon lighting was first exploited when it was realised that discharge from a neon-filled lamp produced vibrant red light. The term "neon lighting" has now come to encompass other gas discharge lamps, including argon, xenon, krypton, and mercury vapour. Phosphor coatings on the inside of the tube may be used to tune the emission, producing a wide array of colors. Phosphorescent materials emit at a longer wavelength than they absorb, as the absorbed radiation undergoes a Stokes shift. Examples of phosphors include BaMg2Al16O27:Eu2+ (450 nm blue emission), Zn2SiO4(Mn,Sb)2O3 (528 nm green emission), Mg4(F)(Ge,Sn)O6:Mn (658 nm red emission). In conventional neon lighting, when the lamp is switched on, the cathode is heated to its thermionic emission temperature, thus liberating electrons. A variation on this principle is cold-cathode lighting, in which electrons are liberated below the thermionic emission temperature. Consequently, cold-cathode tubes typically last longer than conventional neon lights, however they are less efficient. A further advantage is that they can be instantly switched on and off. Neon lighting can last for many years, however the tubes are susceptible to absorption of the gas by the glass walls of the tube, increasing the resistance of the tube such that it cannot be illuminated by the applied voltage. Further, there are issues surrounding the safety of neon lights; tubes can be under a partial vacuum, and thus if broken can implode. Toxic mercury vapor may be released. If a cut is sustained from phosphor-coated glass, the phosphor can prevent blood clotting. Since gas discharge lamps have high energy losses as heat, their use is limited to applications that are out of human reach to minimise the risk of burns through physical contact.
The use of light-emitting diodes (LEDs) in illuminated signage is becoming increasingly popular. LEDs are used both directly as the lighting source and indirectly as backlights in conjunction with color filters. LEDs are traditionally made from inorganic semiconductors, which emit at a specific wavelength, e.g. AlGaInP (red), GaP (green), ZnSe (blue). Other forms of solid-state LED lighting include organic light-emitting diodes (OLEDs), wherein the emissive layer is a conjugated organic molecule such that delocalised π electrons are able to conduct through the material, and polymer light emitting diodes (PLEDs), in which the organic molecule is a polymer. Advantages of SSL over traditional incandescent lighting include superior longevity, lower energy consumption resulting from less energy loss as heat, superior robustness, durability and reliability, and faster switching times. As little heat is dissipated, the bulbs are safe to touch, which is particularly advantageous for signage applications as it allows the sign to safely be cleaned and maintained during or shortly after illumination. However, SSL is expensive, and it is difficult to produce high quality white light. Several approaches to produce white light from solid-state LEDs have been explored. White light can be obtained by using three or more LEDs of differing wavelengths, e.g. with red, green and blue emission, producing high efficiency white light. However, this approach is very expensive and it is difficult to produce pure white light. Other approaches combine an LED emitting in the UV or blue region of the electromagnetic (EM) spectrum with a phosphor. One such approach is to use a combination of a UV or blue LED with a number of phosphors, e.g. a red and a green phosphor, such as SrSi:Eu2+ and SrGaS4:Eu2+, respectively. Alternatively, a blue LED and a yellow phosphor may be combined, producing a less expensive white light source, however the color control and color rendering index of such materials is usually poor, owing to the lack of tuneability of the LED and phosphor.
Lightboxes may be used for backlighting in illuminated signage. LED or fluorescent lighting may be employed. The face panel that contains the image may be made from translucent acrylic or flex-face materials. Flex-face material allows a sign of any size to be fabricated from a single piece of material, thus avoiding the challenges involved with joining adjacent acrylic panels. Lightboxes are advantageous for temporary signage, such as advertisements, as the fascia may be readily substituted without having to change the backlighting. However, the lighting is restricted to a single color of light.
Dot matrix signs are typically used to display messages, such as announcements on public transport. The sign consists of a matrix of lights, from LEDs, liquid crystals or cathode ray tubes. The lights can be switched on or off to display text and graphics, which may also be programmed to scroll across the display. Though dot matrix signs are relatively inexpensive, reliable and easy to read, they are usually restricted to single color displays so that the display may readily be changed.
Side-emitting fibre optic cables may be used as an alternative to neon lighting for signage applications. In fibre optics, light from an LED or laser source is transmitted along a glass fibre that consists of a transparent core enclosed in a lower refractive index cladding material to result in total internal reflection. For side-emitting cables, there is a rough interface between the core and the cladding material, such that not all light is totally internally reflected and a small amount is scattered. No heat or electricity is transmitted through the optical fibres, making them safe for outdoor use in all weather conditions, which is particularly advantageous for safety signage. Neither is there a risk of sparks from a broken fibre. Typical light sources include LEDs, quartz halogen lamps and xenon metal halide lamps. Drawbacks of fibre optics include high installation costs, and for side-emitting fibres the length of cable is limited due to the loss of light along the cable.
Lenticular displays, which may be illuminated, are used to produce an image that appears to move or change as it is viewed from different angles. Lenticular displays are particularly suited to advertising signage. Disadvantages of lenticular displays include their high production cost and the display thickness, which may be large due to the lenses required.
Plasma displays exploit a similar technology to discharge and fluorescent lighting. Millions of tiny cells are encased between two glass panels. The cells contain a mixture of noble gases and mercury. When a voltage is applied across a cell, the mercury vaporises and a plasma forms. As the electrons collide with the mercury atoms, UV light is emitted, which excites the phosphor coating on the inside of the cell to produce visible or infrared (IR) radiation. Approximately 60% of radiation is typically emitted in the IR. In a plasma display, each pixel consists of three cells: one emitting red, one emitting green and one emitting blue light. Different colors are produced by varying the voltage. Advantages of plasma displays for signage applications include that they have a wider viewing angle than other forms of display, such as liquid crystal displays (LCDs). Further, they have a slim profile. However, plasma display screens are relatively expensive to produce and operate, with higher energy consumption than LCDs and LEDs. They often suffer from "screen-door effects", where the fine lines between pixels become visible. Plasma display signage is poorly suited for use at high altitudes, since the pressure differential between the air pressure and that of the gases inside the display can create a buzzing sound.
Electroluminescent (EL) displays are made from semiconducting material sandwiched between two conducting layers. The bottom layer is usually made from a reflective material, while the top layer is usually a transparent conductor, such as indium tin oxide, to transmit light. When an electric current is passed through an EL material, the atoms are excited, causing them to emit photons. The color may be modified by varying the semiconducting material. EL materials are useful for signage applications, as they are tuneable to virtually any color, providing monochromatic light with a narrow emission peak. The brightness is uniform from any viewing angle. Further, the display screens are usually thin, and have low power consumption. However, high operating voltages (>150 V) are typically required to power EL displays.
Signage may be constructed from liquid crystal displays, which require a backlight, usually from a cathode ray tube. Liquid crystals within the display change their alignment in response to an electric field; this change alters the light transmitted through the device, thus changing the image. For signage applications, liquid crystals provide a lower-energy alternative to fluorescent tubes, and are also safer to dispose of. They may be made into compact and lightweight displays in most shapes and sizes. However, disadvantages include slow response and switching times, which may be unfavorable for dynamic displays, along with a limited viewing angle.
The display technologies currently available for illuminated signage applications provide a variety of formats and colors, which may be more suitable for one particular application over another. Each technology presents its own advantages and disadvantages, however there appears to lack a system that encompasses inexpensiveness and ease of manufacture, with low operating costs, and the availability in a range of colors spanning the entire visible spectrum, in a compact package that may be made to any dimensions desired. In view of the existing technologies, there is a need for a low-power static display that may be produced quickly and inexpensively in a wide range of colors, in any size or shape, which is suitable for use in a range of situations and environments. It is also desirable that the display can be operated safely and poses limited health and safety risks both if damaged and at the end of its lifetime.
Color Tuneability
Displays using a single-colored backlight with a remote medium to tune the emission are often favorable over multiple colored illumination sources, owing to their ease of production and because the electrical circuitry requirements are minimised. LEDs are increasingly replacing incandescent and gas discharge lighting sources for backlighting, since they display superior longevity, lower energy consumption resulting from less energy loss as heat, superior robustness, durability and reliability, and faster switching times. However, with SSL it is difficult to achieve high quality white light and their intensities vary considerably with color. Thus, methods to tune the emission from SSL remotely are frequently employed. Current techniques used to achieve secondary monochromatic light from a backlit source for illuminated signage include color filters and phosphors.
Color filters comprise a white LED backlight with a range of filters to transmit blocks of monochromatic light (FIG. 1). Color filters are often favored as they are inexpensive to produce, however energy losses are high (typically 50-90%), since undesired wavelengths are absorbed by the filter. Thus, the resultant energy output is typically low. In addition, color filters require a broad-spectrum light source; white light is difficult to achieve from LEDs and consequently they are expensive.
Color tuneability may be achieved by combining an LED emitting in the UV or blue region of the electromagnetic (EM) spectrum with a phosphor; phosphorescent materials emit at a longer wavelength than they absorb, as the absorbed radiation undergoes a Stokes shift. Phosphors are traditionally fabricated from transition metal- or rare-earth-doped compounds. Examples include SrSi:Eu2+, MgF2:Mn, InBO3:Eu and SrGaS4:Eu2+, which emit in the red, orange, yellow and green, respectively. Color tuneability is limited by the range of phosphors available. The lifetime efficiencies of phosphors are limited, due to oxidation, crystal lattice degradation, and diffusion processes. Further, they are typically insoluble, making them difficult to process.
QDs, semiconductor nanoparticles of the order of 2-50 nm, can be tuned to emit at any wavelength from the UV to the near-IR region of the electromagnetic spectrum by controlling the particle size, without changing the inherent material.
II-VI chalcogenide semiconductor nanoparticles, such as ZnS, ZnSe, CdS, CdSe and CdTe, have been extensively studied. In particular, CdSe has been widely investigated due to the tuneability of its photoluminescence over the visible range of the EM spectrum. Many reproducible, scalable syntheses are described in the prior art, from a "bottom up" approach, whereby particles are synthesised atom-by-atom, from molecules, to clusters, to particles. Such approaches use "wet chemistry" techniques.
Owing to the toxicity of Cd, it is unfavorable for commercial applications; legislation restricting the use of heavy metals in commercial products is being implemented across the globe, e.g. EU directive 2002/95/EC, "Restriction of the Use of Hazardous Substances in Electronic Equipment" prohibits the sale of new electrical and electronic equipment containing lead, cadmium, mercury, and hexavalent chromium above a specified level. Consequently, attempts to synthesize heavy metal-free quantum dot semiconductors have been explored. One such candidate is the Group III-V semiconductor InP, as well as alloys of this material with other elements. Though the photoluminescence is not typically as narrow as that of Cd-based quantum dots, InP-based semiconducting nanoparticles may be synthesised on a commercial scale with full-width half-maxima (FWHM)<60 nm and photoluminescence quantum yields (PLQY)>90%, and their emission may be tuned across the visible spectrum, from the blue to the red region.
The unique properties of quantum dots arise from their dimensions. As a particle's dimensions decrease, the ratio of the surface to the interior atoms increases; the large surface area-to-volume ratio of nanoparticles results in surface properties having a strong influence on the properties of the material. Further, as the nanoparticle size decreases, the electronic wavefunction becomes confined to increasingly smaller dimensions, such that the properties of the nanoparticle become intermediate between those of the bulk material and individual atoms, a phenomenon known as "quantum confinement". The band gap becomes larger as the nanoparticle size is reduced, and the nanoparticles develop discrete energy levels, rather than a continuous energy band as observed in bulk semiconductors. Thus, nanoparticles emit at a higher energy than that of the bulk material. Due to Coulombic interactions, quantum dots have higher kinetic energy than their bulk counterparts, thus a narrow band width, and the band gap increases in energy as the particle size decreases.
QDs made from a single semiconducting material passivated by an organic layer on the surface are known as "cores". Cores tend to have a relatively low quantum efficiency, since electron-hole recombination is a facilitated by defects and dangling bonds on the surface of the nanoparticles, leading to non-radiative emission. Several approaches are used to enhance the quantum efficiency. The first approach is to synthesise a "core-shell" nanoparticle, in which a "shell" layer of a wider band gap material is grown epitaxially on the surface of the core; this serves to eliminate the surface defects and dangling bonds, thus preventing non-radiative emission. Examples of core-shell materials include CdSe/ZnS and InP/ZnS. A second approach is to grow core-multishell, "quantum dot-quantum well", materials. In this system, a thin layer of a narrow band gap material is grown on the surface of a wide band gap core, then a final layer of the wide band gap material is grown on the surface of the narrower band gap shell. This approach ensures that all photoexcited carriers are confined to the narrower band gap layer, and examples include CdS/HgS/CdS and AlAs/GaAs/AlAs. A third technique is to grow a "graded shell" QD, where a compositionally-graded alloy shell is grown epitaxially on the core surface; this serves to eliminate defects resulting from strain. One such example is CdSe/Cd1-xZnxSe1-ySy.
QD emission may be tuned to higher energies than the band gap of the bulk material by manipulating the particle size. Methods to alter the absorption and emission to lower energies than that of the bulk semiconductor involve doping wide band gap QDs with a transition metal to form "d dots". In one example, Pradhan and Peng describe the doping of ZnSe with Mn to tune the photoluminescence from 565 nm to 610 nm [N. Pradhan et al., J. Am. Chem. Soc., 2007, 129, 3339].
QD phosphors may be used to down-convert the emission from an inexpensive UV or blue solid-state lighting source. Since QDs may easily be synthesised in any color by manipulating the particle size, the emission may be tuned right across the visible range of the EM spectrum to produce any desired color of display.
In an earlier patent application (US 2010/0123155 A1, filed Nov. 19, 2009, the entire contents of which are incorporated herein by reference), we discuss the preparation of "QD-beads", in which QDs are encapsulated into microbeads comprising an optically transparent medium; the QD-beads are then embedded in a host LED encapsulation medium. Bead diameters may range from 20 nm to 0.5 mm. QD-beads offer enhanced stability to mechanical and thermal processing relative to "bare" QDs, as well as improved stability to moisture, air, and photo-oxidation, allowing potential for processing in air, which could reduce manufacturing costs. By encapsulating the QDs into beads, they are also protected from the potentially damaging chemical environment of the encapsulation medium. Microbead encapsulation also serves to eliminate the agglomeration that is detrimental to the optical performance of bare QDs as phosphors.
Examples of QD phosphors for display technologies are described in the prior art, however most are based on II-VI and IV-VI semiconductors, such as CdSe and PbSe. Where heavy metal-free QDs are proposed, examples of device fabrication and efficiency have not been discussed.
U.S. Pat. Nos. 7,405,516 B1 and 7,833,076 B1 propose the addition of QDs to the outer shell of a plasma-display device to tune the emission from the gas discharge, however no examples of suitable QDs or methods for their incorporation are offered.
U.S. Pat. No. 7,857,485 B2 discloses an LED display device using LEDs that emit UV or blue light, then a luminescent material, for instance QDs, to tune the LED emission to the desired wavelength. No QD materials are suggested, and no examples of device fabrication using QDs are given.
Patent application US 2009/023183 A1 describes a backlight module comprising a light source and a series of wavelength converters positioned nearby to tune the emission. After passing through a wavelength converter, which may be fabricated from QD material, one portion of converted light is emitted while the remainder is directed towards another wavelength converter. No examples of suitable QD material or their use in device fabrication are disclosed.
A number of patents and patent applications propose the use of QD materials as phosphors. EP 1 758 144 A1, EP 1 775 748 A2, US 2007/0046571 A1 and US 2007/0080640 A1 all describe a plasma display panel device including a QD phosphor layer. EP 1 788 604, U.S. Pat. No. 7,667,233 B2 and US 2007/0117251 A1 disclose a flat lamp plasma display device with a phosphor layer that may be made from QDs. US 2007/0090302 A1 describes a display device including a phosphor layer that may be excited by gas discharge. The phosphor layer may be fabricated from QDs. Though each of these patents makes reference to the use of QDs as phosphors for display technologies, no examples of their use in devices or suitable QD material are provided.
Najjar et al. describe a fluorescent screen and display device with at least one excitation optical beam to excite one or more fluorescent materials on a screen, in patent application US 2006/0221021 A1. The fluorescent material may include phosphors and non-phosphors, such as QDs, though no examples of suitable QDs are specified. Device fabrication incorporating QDs is not exemplified.
The patent application US 2007/0080642 A1 by Son et al. describes a gas discharge display panel with a phosphor layer than may include QDs, but examples of suitable QDs or displays in which they are used are not provided.
Park et al. describe a gas discharge cell with two luminescent layers in patent application US 2007/0241682 A1. The first luminescent layer is composed of a phosphor, while the second may be made of a cathode luminescent or QD materials, though an appropriate QD material is not suggested. No examples of device fabrication with QDs are provided.
The patent application US 2008/019772 by Nam et al. describes a display device comprising a gas discharge tube and red, green and blue phosphors to produce white light. Traditional phosphors or alternatively QD material, which may be printable, may be used. The QD material is not specified, and neither is its printability or incorporation into a display device exemplified.
Bretchnelder et al. propose a light emitting unit, which may comprise an LED and a remote luminescent material, which could include QDs, in patent application publication WO 2011/103204 A2. Examples of suitable QDs and description of their use are not given.
The patent application US 2009/0034230 A1 describes an illumination device that may combine solid state lighting with a wavelength converting material, such as a phosphor and/or QDs, to down-convert the emission. Examples of QD materials and their use are not provided.
Patent application US 2007/0188483 A1 describes display apparatus for outdoor signage. Though it is mentioned that QD material may be used to fabricate an electronic paper-like display, no examples of appropriate QDs or their use in device fabrication are provided.
Two published international patent applications, WO 2010/123809 A2 and WO 2010.123814 A1, describe a display device comprising LEDs with an active layer of quantum wells sandwiched between two doped semiconducting layers, acting as a wavelength converter to down-convert light from the LED source. Despite proposing Group IV: Si or Ge, III-V, or II-VI QDs as appropriate materials, their utilization in display devices is not demonstrated.
The patent EP 2 270 884 A1 describes a display device with a light source and a wavelength modulator, separated by a spacer. The wavelength modulator may be made from an inorganic QD phosphor, although description of its use in the device is not included.
US 2011/0249424 A1 and EP 2 381 495 A2 describe an LED package with an LED backlight and a wavelength converting material. The wavelength converting material may be made from a phosphor and/or QDs. Suitable QDs include Group II-VI and III-VI materials, however no examples are provided for their incorporation into the LED package.
The patent application WO 2010/092362 A2 describes a device having LEDs in close contact with colloidal QDs. CdTe and core-shell CdSe/CdS are given as suitable QD materials, though examples of their use are not provided.
Patent application US 2011/0182056 A1 describes an LED device fabricated from bulk semi-polar or non-polar materials with emission tuned by phosphors, in their The phosphors may be made from QDs, including CdTe, ZnS, ZnSe, ZnTe, and CdSe, to tune the emission with a minimal effect on brightness. No examples are given to demonstrate the use of QDs in devices.
U.S. Pat. No. 8,017,972 B2 and US 2007/0246734 A1 describe a white LED device composed of a UV LED with blue and green phosphors, along with red QDs, which have better luminescence than red phosphors. The QDs are excited by the emission from the blue and green phosphor photoluminescence to alleviate the damaging effect of direct QD exposure to UV light. Group II-VI and III-V QDs are included as suitable materials, though only red CdSe QD synthesis is disclosed.
The patent applications US 2006/0157686, JP 2006/199963 A and US 2011/0121260 A1 describe QD phosphor preparation, with a formulation in which the nanoparticles do not aggregate in the resin, for use in LEDs. It is suggested that the QDs may be mixed with inorganic phosphors. Group II-VI and III-V QD materials are stated as appropriate materials, though only CdSe/CdS core-shell QD synthesis (with 85% quantum yield) is disclosed. Methods for LED preparation are also described.
U.S. Pat. No. 8,030,843 and US 2010/0066775 A1 describe a method for producing QD phosphors for use with UV LEDs. The phosphor material comprises a QD core with an organic capping material and an activator layer. ZnS and ZnO are proposed as appropriate QDs, and their synthesis is included. The synthesis is not by a colloidal method, thus a two-step process is required to synthesise then cap the particles with organic substances such as mercaptosuccinic acid and dithiosquaric acid.
The patent application US 2011/0156575 A1 includes a display device with an illumination unit comprising an LED chip and QD phosphors, and a color filter to enhance the display. It is claimed that red, green and blue QD phosphors may be used, fabricated from both Cd and Cd-free materials. Some data is included to support the use of CdSe/ZnSe QDs.
US 2008/0246017 A1 describes methods for fabricating LED chips with a layer of nanoparticles to tune the emission. It is claimed that Group II-VI, IV-VI, III-V, and I-II-VI QDs may be used. Examples highlighting the color mixing ratios to achieve specific colored emission from QDs emitting at various wavelengths are provides, however only CdSe and PbS QDs are used. No details of QD synthesis are included.
US 2008/0173886 A1 describes a method to produce solid-state lighting using QDs dispersed in acrylates, deposited over the light source to down-convert the emission. It is claimed that Group II-VI, III-V, IV-VI cores, shelled with Group II-IV, III-V, or IV-VI materials or with metals such as Cd, Zn, Hg, Pb, Al, Ga or In, may be used. Methods for QD dispersion and the curing process are described. Examples are included where red CdSe, green CdSe, red and green CdSe, and PbSe have been used in devices, however no QD synthesis is detailed.


A novel class of cationic peptides having antimicrobial activity is disclosed. These peptides can be encompassed by the formulas:

Systemic diseases that are associated with pathogenic microorganisms or their toxins in the blood (e.g., septicemia) are a leading cause of death among humans. Gram-negative bacteria are the organisms most commonly associated with such diseases, and pathogenesis has been related in many cases to the release of a toxic outer membrane component termed endotoxin. However, gram-positive bacteria are an increasing cause of fatal infections. In addition, antibiotic resistance is becoming a major problem for all classes of antibiotics, and novel antibiotics are urgently needed.
Cationic peptides having antimicrobial activity have been isolated from a wide variety of organisms. In nature, such peptides provide a defense mechanism against o microorganisms such as bacteria and yeast. Generally, these cationic peptides are thought to exert their antimicrobial activity on bacteria by interacting with the cytoplasmic membrane to form channels or lesions. In gram-negative bacteria, they interact with surface lipopolysaccharide (LPS) to permeabilize the outer membrane, leading to self promoted uptake across the outer membrane and access to the cytoplasmic membrane. Examples of antimicrobial peptides include indolicidin, defensins, cecropins, and magainins.

Abstract: X1X1PX2X3X2P(X2X2P)nX2X3(X5)0;(SEQ ID NO:23) X1X1PX2X3X4(X5)rPX2X3X3;(SEQ ID NO:24) X1X1X3(PW)uX3X2X5X2X2X5X2(X5)0; and(SEQ ID NO:25) X1X1X3X3X2P(X2X2P)nX2(X5)m;(SEQ ID NO:26)wherein:                m is 1 to 5;        n is 1 or 2;        o is 2 to 5;        r is 0 to 8;        u is 0 or 1;        X1 is Isoleucine, Leucine, Valine, Phenylalanine, Tyrosine, Tryptophan or Methionine;        X2 represents Tryptophan or Phenylalanine        X3 represents Arginine or Lysine;        X4 represents Tryptophan or Lysine; and        X5 represents Phenylalanine, Tryptophan, Arginine, Lysine, or Proline.

Abstract: The invention also provides a method of producing a cationic peptide variant having antimicrobial activity.