A linear time-invariant system modeling apparatus comprises a processing resource arranged to receive, when in use, model data constituting to a model of a linear time-invariant system. The model data includes residual value data and scattering data. The processing resource is arranged to perform, when in use, a single value decomposition in respect of the scattering data; the scattering data corresponds, when expressed in matrix form, to a scattering matrix in a state-space representation of the model. The processing resource is also arranged to use, when in use, a result of the single value decomposition in order to generate residual value modification data. The residual value modification data is applied to the residual value data, the residual value data corresponding, when expressed in the matrix form, to a residual value matrix in the state-space representation of the model.

The present invention relates to a linear time-invariant system modeling apparatus of the type that, for example, is used to characterize behavior of the linear time-invariant system in a time-domain. The present invention also relates to a method of generating a passive model of a linear time-invariant system from a non-passive model of the linear time-invariant system, the method being of the type that, for example, is used to characterize behavior of the linear time-invariant system in a time-domain.
In the field of electronic design, engineers, for example microwave engineers, need to analyze, design, and simulate active and passive microwave components and systems. In the face of complex communications signal formats, design verification is challenging. Furthermore, whilst designs can be analyzed early in simulation and verified later once a prototype has returned from fabrication, modern pressures upon vendors to respond rapidly to market requirements means that the designer does not necessarily have the luxury of waiting for fabricated hardware to complete a design. Consequently, designers employ an intermediate level of verification to cut overall design time and reduce risk and cost.
In this respect, the field of electronic design automation strives to provide engineers with tools for modeling and analyzing performance of a design or a part thereof. One known suite of analysis tools for so-called high-frequency design is the Advanced Design System (ADS) available from Agilent Technologies, Inc. The ADS is a Computer Aided Design (CAD) program that supports system and RF design engineers when developing all types of Radio Frequency (RF) designs, ranging from, for example, RF/microwave modules to Monolithic Microwave Integrated Circuits (MMICS) for communications, aerospace and other applications.
The ADS provides a set of simulation technologies ranging from frequency-domain circuit simulation to electromagnetic field simulation. A single, integrated, design environment provides system and circuit simulators, along with schematic capture, layout, and verification capability, thereby eliminating interruptions associated with changing design tools mid-cycle during development. Indeed, verification very early in a prototyping cycle for applications is possible Furthermore, the ADS enables designers to characterize fully and optimize designs. In relation to electromagnetic simulation and/or measurement, most commercial simulation and/or measurement tools perform the simulation and/or measurement in the frequency domain. In this respect, a set of frequency points, for example between 0 Hz and 10 GHz, and associated values, for example amplitudes, are sampled for analysis purposes. However, in order to perform a so-called transient simulation, information is required in the context of the time domain, and significant difficulty is associated with converting frequency domain data to the time domain.
Often, it is necessary to model a so-called Linear Time Invariant (LTI) system. Generally speaking, most passive components either alone or in combination constitute members of a group of LTI systems. A physical example of the LTI system is a microstrip transmission line, a known type of electrical circuit designed to transmit efficiently electromagnetic energy at high frequencies where traditional circuits become inefficient, that needs to be designed and analyzed. The LTI system can be represented in the form of a rational function. In this respect, two examples techniques used to identify the rational function are so-called Vector Fitting (VF), for example as described in "Rational Approximation of Frequency Domain Responses by Vector Fitting" (B. Gustavsen and A. Semlyen, IEEE Transactions on Power Delivery, 14:1052-1061, July 1999), and direct interpolation, for example as described in "Generation of Accurate Rational Models of Lossy Systems using the Cauchy Method" (T. K. Sarkar, A. G. Lamperez and M. S. Palma, Microwave and Wireless Components Letters, 14:490-492, October 2004). In both cases, one obtains a rational function (model) in the Laplace domain of the form:
                                          S                          n                                                                                m                                                      (            s            )                          =                              d                          n                                                                                m                                +                                    ∑                              k                =                1                            K                                                                  c                k                                  n                                                                                m                                                            s                -                                  p                  k                                      n                                                                                m                                                                                (        1        )
In equation (1) above, Snm is an element at row n, column m of a scattering matrix. dnm is a constant contribution, pknm represents the poles of the rational function and cknm are residues of the rational function. All elements of the scattering matrix can be fitted to the same set of poles (pknm=pk) or with a separate set of poles can be used in respect of each element of the scattering matrix.
It is, of course, important that, when performing a simulation, the rational function employed is as close to the actual data initially obtained, either empirically or by simulation, for the LTI system being modeled so that behavior of the LTI system is modeled accurately. In order to obtain physically meaningful simulations in the time domain, it is necessary that the model is passive.
Equation (1) above can be represented in a compact matrix form:S(s)=D+C(sI−A)−1B  (2)
Matrix, D, is a square matrix containing the elements dnm. The matrix, C, contains the residues cnm, and matrix, A, is a complex or real matrix containing the poles pnm. The matrix, B, comprises 0's and 1's, mapping the poles and residues to the correct element locations in the scattering matrix, for example as described in "Equivalent SPICE Circuit With Guaranteed Passivity From Non-Passive Models" (A. Lamecki and M. Mrozowski, IEEE Transactions on Microwave Theory and Techniques, 55:526-532, March 2007). Matrix, I, is the identity matrix of the same size as the matrix, A. It should be appreciated that the inversion of (sI−A) is trivial since matrix, A, is a diagonal matrix.
The set of matrices ABCD is referred to as a "state-space representation" of the rational function expressed in equation (1) above, and describes the broadband behavior of the LTI system in both the frequency- and the time-domain. In this respect, for simulation purposes, it is not sufficient for the model to represent the LTI system over the range of data initially obtained, and it is typically necessary to be able to model the broadband behavior of the LTI system being modeled. In order to "map" the rational function, which is a model of reduced-order, to a (non-linear) circuit simulation scenario, one has to represent the rational function (model) in the state-space form:
                    {                                                                                x                    .                                                                          (                    t                    )                                                  =                                                      Ax                                                              (                      t                      )                                                        +                                      Bu                                                              (                      t                      )                                                                                y                                                        (                    t                    )                                                  =                                                      Cx                                                              (                      t                      )                                                        +                                      Du                                                              (                      t                      )                                                                                (        3        )
In equation (3), u(t) is an input signal and y(t) is an output signal, where x(t) is a so-called "internal state" of equation (3), x(t) being the first derivative of x(t) with respect to time.
It is assumed that the LTI system is causal and strictly stable. Consequently, all poles, in particular all eigenvalues of the matrix, A, have negative real parts.
As mentioned above, it is necessary for the rational function described above to be passive in order to perform physically meaningful simulations in the time domain. In this respect, the model of the LTI system is passive if no energy is created within the system represented by the model. Consequently, in order to have a passive state, it is required that, in the frequency domain (i.e. s=jω), all singular values, σ(jω), of the scattering matrix, S(s=jω) are smaller than 1.0, as described in "Passivity Enforcement via Perturbation of Hamiltonian Matrices" (S. Grivet-Talocia, IEEE Transactions on Circuits and Systems, 51:1755-1769, September 2004):
                                                                                max                  ω                                                                  σ                                                        (                    jω                    )                                                              ≤              1.0                                                          ∀              ω                                                          (        4        )
Clearly, due to the infinite number of frequencies, one cannot check the above criterion of inequality (4) for all possible frequencies. Consequently, a purely algebraic test is described in "Passivity Enforcement via Perturbation of Hamiltonian Matrices" (S. Grivet-Talocia, IEEE Transactions on Circuits and Systems, 51:1755-1769, September 2004) and "A bisection method for computing the H∞ norm of a transfer matrix and related problems" (V. Balakrishnan, S. Boyd and P. Kabamba, Math. Control Signals Syst., 2:207-219, 1989). Indeed, a Hamiltonian matrix can be constructed having the following form:
                    H        =                  [                                                                      A                  -                                                            BR                                              -                        1                                                                                D                      T                                                            C                                                                                -                                          BR                                              -                        1                                                                                B                    T                                                                                C                    T                                                                          Q                                          -                      1                                                                          C                                                                                -                                          A                      T                                                        +                                                            C                      T                                                                                DR                                              -                        1                                                                                B                      T                                                                                ]                                    (        5        )
In Hamiltonian matrix (5), Q=DTD−I and R=DDT−I. Furthermore, it can be proven that the state-space model is guaranteed to be passive if the Hamiltonian matrix, H, has no purely imaginary eigenvalues:Re{λi}≠0.0 ∀λiελ(H)  (6)
The condition set forth in inequality (6) is a sufficient condition, and it has also been proven that if jω0 is an eigenvalue of the Hamiltonian matrix, H, ω0 is a so-called "cross-over frequency" from a passive frequency interval to a non-passive frequency interval or vice-versa where the model lacks passivity.
If the model is not passive, the challenge is therefore to modify the state-space representation, ABCD, so that all eigenvalues of the Hamiltonian matrix, H, have a non-vanishing real part, whilst preserving the overall behavior of the model pre-modification. In this respect, a number of so-called "passivity enforcement" methods are in existence. For example, "Passivity Enforcement via Perturbation of Hamiltonian Matrices" (S. Grivet-Talocia, IEEE Transactions on Circuits and Systems, 51:1755-1769, September 2004) describes a method of directly modifying the Hamiltonian matrix, H, by evaluating a first-order approximation of perturbation of the eigenvalues by modifying the residues. However, this technique is computationally expensive, because an eigenvector determination of the Hamiltonian matrix, H, is required and the Hamiltonian matrix, H, grows in accordance with 2Np2K, Np being the number of ports of the model and K being the number of poles of the model. In "Equivalent SPICE Circuit With Guaranteed Passivity From Non-Passive Models" (A. Lamecki and M. Mrozowski, IEEE Transactions on Microwave Theory and Techniques, 55:526-532, March 2007), instead of perturbing the residues, a method is described that involves perturbation of the poles. However, this technique also requires the eigenvector calculation of the Hamiltonian matrix, H.
"Computer Code for Passivity Enforcement of Rational Macromodels by Residue Perturbation" (B. Gustavsen" IEEE Transactions on Advanced Packaging, 2:209-215, May 2007), "Fast Passivity Verification and Enforcement via Reciprocal Systems for Interconnects With Large Order Macromodels" (R. Achar, D. Saraswat and M. Nakhla, IEEE Transactions on Very Large Scale Integration (VLSI) systems, 15:48-59, January 2007), and "A Fast Algorithm and Practical Considerations for Passive Macromodeling of Measured/Simulated Data, IEEE Transactions on Advanced Packaging, 27:57-70, February 2004), describe different passivity enforcement techniques, but these techniques are also computational very expensive since a constrained optimization problem must be solved iteratively. Consequently, the high computation cost results in increased demand upon a processing resource supporting simulation software and hence, typically, reduced performance speeds. Also, a number of the passivity enforcement techniques described are not always capable of ensuring passivity without introducing an unacceptably large deviation into data generated by the revised model from the data generated by the original model.

Linear time-invariant system modeling apparatus and method of generating a passive model


The present invention relates to a novel polyrotaxane compound having a specific chemical structure, a photocurable coating composition that may provide a coating material having excellent mechanical properties such as scratch resistance, chemical resistance, abrasion resistance, and the like, and excellent self-healing capability, and a coating film obtained from the photocurable coating composition.

To protect against product damage by mechanical, physical, and chemical influences from the outside, various coating layers or coating films are applied on the surface of electrical and electronic devices such as mobile phones, electronic components, home appliances, automobile interior/exterior parts, plastic molded products, and the like. However, since scratches on the surface of product coating or cracks due to external impact lower appearance properties, performance, and cycle life, various studies are progressing to protect a product surface to maintain product quality for a long period of time.
Particularly, studies on coating materials having self-healing capability are actively progressing because they do not require an additional coating or repair process even when the surface is damaged, and are extremely favorable for appearance and performance maintenance of products. As a result of these studies, UV curable compositions using self-healing oligomers and inorganic particle or fluorinated compound-added compositions for improving scratch resistance and anti-pollution have been suggested, but coating materials obtained from the compositions may not have sufficient surface hardness and self-healing capability.
Further, previously known coating materials using urethane resin are two-component types of solutions thus requiring a process of combining two kinds of materials, they have low storage stability in a combined state, and the curing time is several tens of minutes.
A coating composition including a polymer or an active polymer material, or including particles or capsules treated therewith on the surface have been suggested. Although a coating layer using the composition exhibits self-healing capability to external impact, it does not have sufficient mechanical properties such as scratch resistance or durability, and compatibility between each component is low.
Recently, it has been suggested that if a coating material including a polyrotaxane compound is used, a coating film or a coating membrane having self-healing capability may be provided, and various methods are being attempted to apply the polyrotaxane compound in coating of automobiles or electronic products, and the like to commercialize it.
For example, WO2005-080469 describes substituting hydroxyl groups of a cyclic molecule α-cyclodextrin with hydroxypropyl groups or at a high substitution rate of methyl groups to improve properties of polyrotaxane.
WO2002-002159 describes crosslinking cyclic molecules α-cyclodextrin) of polyrotaxane using polyethylene glycol.
WO2007-026578 describes a method for preparing polyrotaxane that can be dissolved in toluene or ethyl acetate by substituting hydroxyl groups of α-cyclodextrin with hydrophobic groups of ε-caprolactone, and WO2010-092948 and WO2007-040262 describe paint including polyrotaxane wherein hydroxyl groups of α-cyclodextrin are substituted by hydrophobic groups of ε-caprolactone.
WO2009-136618 describes polyrotaxane wherein a part or all of the hydroxyl groups of the cyclic molecule α-cyclodextrin are substituted by residues of an organic halogen compound to form a radical polymerization initiation part.
However, to prepare previously known polyrotaxane compounds, a synthesis process consisting of many steps should be conducted, or synthesis conditions of high temperature/high pressure while using very limited solvents are required.
Further, coating materials using previously known polyrotaxane compounds do not have sufficient mechanical properties required for a coating material, such as scratch resistance, chemical resistance, and abrasion resistance, or do not have sufficient self-healing capability to scratches or external damage, and thus have limitations in commercialization.

This patent is subject to a terminal disclaimer.

Poly-rotaxane compound, photocurable coating composition, and coating film


To achieve, in a load drive device including an H-bridge circuit, miniaturization of a capacitor or/and the constituent elements of the H-bridge circuit (e.g., reduction in volume) with circuit elements, for example, switching elements included in the H-bridge circuit, being inhibited from breaking down or destroying even in a case where a load is overloaded. The invention is disclosed in which, as a solution to the achievement, first and second modes are provided as a switching mode for the switching elements 11, 12, 13, and 14 and switching is appropriately performed between the first and second modes.

A drive device using an H-bridge drive circuit, has been known as a drive device that drives a motor including a coil. The motor drive device using the H-bridge drive circuit, includes four switching elements diagonally connected to the motor to cross each other, and turns the switching elements ON or OFF in a predetermined duty cycle so that the operation state of the motor (positive rotation, negative rotation, and stop) can be controlled.
In making a switch from the operation state of the positive rotation or the negative rotation to the state of the stop, energy that has been stored and remains in the coil in the motor, is required to be discharged, and thus a method described below has been known. Refer to Patent Literature described below.
Four switching elements all are turned OFF, and a diode arranged in parallel between the drive terminals of each switching element is used to apply a bias in the forward direction between the drive terminals of each switching element through each body diode so that energy stored in a coil is discharged to the power source side through each diode.
For example, it is assumed that a motor is suddenly and excessively loaded. When the motor being loaded is left, the drive circuit thereof may break down thermally or electrically. Therefore, in a case where a load drive device or a load drive circuit detects the state where the overload has been applied, energy in the load, for example, inertial energy is required to be promptly discharged to the outside of the drive device or the outside of the circuit. The present inventors have found that, that is, control is required to be performed, for example, kinetic energy is converted into electrical energy at the point in time when the overload is detected and then the electrical energy is further converted into thermal energy, or the electrical energy is stored into a capacitor provided in the circuit.


A spark ignition fuel injection reciprocatory internal combustion engine with dual induction system is provided which has within a cylinder head a primary intake port passage to direct air charge into a cylinder to swirl therein and a secondary intake port passage to direct air charge into the cylinder in such a direction as to impede and reduce the swirling motion of the air charge issuing from the primary intake port passage. An intake valve, including a valve stem and a valve head, is reciprocably mounted within the cylinder head, and an annular wall or tube is fixedly positioned in a bore in the cylinder head. The primary intake port passage communicates with the exterior of this tube and the secondary intake port passage communicates with the interior of the tube. This tube extends to a position closely adjacent to, or in engagement with, the valve head of the intake valve when the valve is in the closed position. A fuel injector, mounted to the cylinder head, discharges fuel into the secondary intake port passage toward the central portion of the head and synchronization with the opening of the intake valve so that the fuel issuing from the fuel injector will impinge upon the valve head and then disperse radially outwardly toward the periphery of the valve head. An air flow sensor is provided upstream of primary and secondary throttle valves to detect the total of flow of induction air fed to the engine so that fuel is discharged at a rate proportional to the total induction air flow.

The present invention relates to an internal combustion engine with dual induction system including a primary induction system to direct a first fluid charge into a cylinder to swirl therein under all operating conditions of the engine and a secondary induction system to direct a second fluid charge into the cylinder in such a direction as to impede and reduce the swirling motion of the first fluid charge issuing from the primary induction system under predetermined operating conditions of the engine, thereby maintaining the volumetric efficiency at sufficiently high level. More particularly, the invention relates to an arrangement of fuel injectors of a fuel injection system for an internal combusiton engine as above.
In the case of installing a fuel injection in the engine with dual induction system as mentioned above, it is possible to arrange two fuel injectors per each cylinder, one for discharging fuel into a primary intake port passage and the other into a secondary intake port passage. The arrangement requires twice the number of fuel injectors as required in the usual induction system for an engine with single induction system. Furthermore, a complicated control for the fuel injector of the secondary intake port passage is required, thus boosting up the cost of the fuel injection system.

Internal combustion engine with dual induction system and with fuel injection system to discharge fuel into secondary induction system


A high capacity motorized rack holds a plurality of jewel case enclosed CDs in holders flexibly inter-connectable with each other to form a rotatable continuous loop. The loop is rotatably retained within a vertical rack housing and is driven by a motor, disposed within the housing, under user control such that the loop is rotated until a desired CD is moved to the top region of the belt. A rack may hold two or more such loops of inter-connected holders. In one embodiment a holder retains a single jewel case, and comprises two independent loops that are rotated with a single motor. A lamp and/or barcode scanner may be disposed on the housing for ease of CD selection. The housing base preferably is detached during shipping to permit transporting the rack in a smaller volume container. User control can include voice commands to direct loop rotation and speed.

CD holders having no moving parts and in the form of vertical towers or horizontal cabinets are known. But when a large quantity of CDs is stored, it can be difficult to display and select a desired CD, especially if the desired CD is stored in the lower portion of a vertical tower.
Applicants' parent application disclosed a motorized modular CD storage device or rack that could store a great many CDs or the like in a rotatable rack that could be rotated until the desired CD was displayed, at which time rotation could be stopped and the desired CD removed from the rack.
Notwithstanding that the disclosed rack could store a great many CDs or other objects and has met with great consumer success, there is a need for a rack with at least double the storage of the disclosed rack. Further, since CDs are often used in an environment with subdued ambient lightning, there is a need for a CD rack that can illuminate CDs retained by the rack, for ease of selection in such an environment. There is a need to promote ease of such of use of such racks, enlarged or otherwise, by providing an option for foot-operable variable speed, and stop and go operation of the rack. Finally, enlarging the holding capacity of such racks typically requires a larger base, for reasons of stability. However, enlarging the base can require a larger carton in which to ship such racks, thus adding to the overall cost of brining the product to the marketplace. Thus, there is a need for base mechanism that provides the requisite stability for a rack yet does not require a larger shipping carton. Further, such rack should provide an option to automatically cease rotation upon scan code recognition a CD or other retained object, or upon voice command from the user. Finally, it is preferred that such rack have the ability to be electronically daisy-chained to other such racks.
The present invention provides such racks.


A method and dispensing apparatus for dispensing a soluble compound into a liquid stream. The dispensing apparatus includes a base having an inlet end and an outlet end with a throughbore connecting said inlet end to said outlet end. The throughbore is of generally constant diameter and unobstructed. A container for housing the soluble compound includes an opening. The container is removably secured to the base by a threaded connection. The base includes inlet and outlet connectors to couple the inlet end of the throughbore to a conduit connected to a liquid source and the outlet end of the throughbore to a lawn sprinkler. The base has an entrance orifice and an exit orifice between the throughbore and the secured container. A stake is adapted to be attached to the base member to secure the apparatus to the ground. The entrance orifice is smaller in diameter than the exit orifice and is typically located upstream of the exit orifice.

1. Field of the Invention
The present invention relates to a dispenser for dissolving and dispensing a soluble compound from a container into a stream of liquid such as water.
2. Description of the Related Art
The key to beautiful, healthy lawns and gardens is the proper application of fertilizer. The fertilizing of garden plants and lawn grass has always presented a problem to homeowners because of the difficulty in evenly applying the proper amount of fertilizer to the plants or grass.
Typically, solid fertilizer in granular form is spread on the ground with a rotary spreader. The application of the solid fertilizer oftentimes results in an uneven distribution over the ground area, resulting in the burning of patches of the lawn or damage to the plants. Heavy rains will often carry the fertilizer off and it will be lost and wasted. The uneven spreading of solid fertilizer causes an oversupply of fertilizer being provided at certain places, which is harmful to the plant, and at other places, an insufficient amount of fertilizer is distributed which fails to properly nourish the plants.
More recently, a popular fertilizer apparatus is a hand-held sprayer which attaches to the end of a garden hose. A water soluble concentrate chemical fertilizer is placed in a canister of the sprayer. The garden hose is connected to a cap member having a throughbore extending therethrough. The throughbore has entrance and exit ends. The canister is attached to the bottom of the cap member. Typically, an inlet orifice and an outlet orifice provide fluid communication between the throughbore and the canister attached to the cap member. Water is supplied through the garden hose to the throughbore of the cap member. A portion of the water stream is allowed to flow directly through the throughbore and exit the cap member. The remaining portion of the water stream is diverted into the canister by a flow restriction device, such as a venturi plug, located in the throughbore between the inlet and outlet orifices. The water diverted into the canister through the inlet orifice dissolves the fertilizer. The canister fills with water dissolving all of the soluble fertilizer. The liquid fertilizer solution is then drawn out of the canister through the outlet orifice by the venturi effect into the stream of water passing directly through the throughbore. One such hand-held sprayer is the Miracle-Gro Lawn & Garden Feeder by Sterns Miracle-Gro Products, Inc. The main drawback to this type of apparatus and method is that it requires a gardener to manually wave the sprayer back and forth, thus increasing the opportunity for poor lawn coverage. Additionally, the manual hand-held sprayer apparatus is tedious for the person using the sprayer. Furthermore, the gardener is required to hold the sprayer during use which often times will be used during the hot summer months. An automatic-type "hands free" apparatus that reduces or eliminates the requirement of gardener participation is desirable.
It is generally known in the prior art to provide devices which attach to water sprinklers or delivery systems for adding desirable compounds to the water passing through the system. The compounds are not limited to fertilizers but may also include pesticides, detergents or other water soluble compounds.
The prior art devices typically utilize a container having a cap member which is connected to a hose or other conduit through which the water is delivered. The cap member has a throughbore through which the water travels on its way to the sprinkler. The container is adapted to contain the soluble compound to be dissolved in the water. A small orifice in the cap member fluidably connects the container to the throughbore. A venturi plug in the throughbore of the cap member downstream of the small orifice serves to backpressure the water upstream of the venturi plug. The venturi plug diverts a small portion of the water stream through the small orifice into the container to dissolve and mix with the soluble compound therein. Downstream of the venturi plug there typically is a large orifice connecting the throughbore with the container. As is well known in the art, the reduced fluid pressure at downstream side of the venturi plug draws liquid from the container through the large orifice and into the stream passing through the throughbore. The resulting mixture is then carried downstream to the sprinkler.
The above-mentioned prior art devices rely on the well-known venturi principles and thus teach an obstruction to the flow of water between the small orifice and the large orifice resulting in a pressure differential between the orifices. The obstructions shown in the prior art include a restricted throughbore between the small and large orifices. See, for example, U.S. Pat. Nos. 5,133,498; 4,941,616; 4,901,923; 4,385,034; 4,333,493; 3,260,464; 3,194,444; 2,302,799; and 1,964,576.
It has been found that the venturi-type devices result in a significant fluid pressure drop at the outlet end of the device. The reduced pressure delivered to the sprinkler reduces the effectiveness of the sprinkler. Thus, the sprinkler covers a reduced surface area and, depending on the type of sprinkler being used, may cause it not to function properly. Since there are several types of sprinklers which require various operating pressures, it is desirable to have a dispensing apparatus which minimizes the fluid pressure drop through the apparatus.
It is further desirable to have a dispensing apparatus for use with underground sprinkler systems, soaker hoses or sprinkler hoses. Soaker and sprinkler hoses are capped at one end. Soaker hoses are porous and allow water to ooze or seep through the hose along its entire length. Sprinkler hoses have pin holes along its length which allow the water to spray the surrounding area with a fine spray or mist.
A general problem encountered in conjunction with the prior art devices is the complexity of the devices and the resulting cost to manufacture such devices. It is desirable to have an apparatus for dissolving and dispensing soluble compounds which is simple to operate, inexpensive to manufacture, and having the versatility to be used with virtually any type of watering apparatus or system without detrimental effect.

Apparatus and method for dissolving and dispensing soluble compounds


Polyetheramide acids and polyetherimides derived therefrom are provided having terminal aliphatically unsaturated groups. The polyetherimides are heat curable, have superior flow characteristics prior to cure, and can be converted to high strength shaped composites when reinforced with various materials such as carbon fibers, glass fibers, etc.

The present invention relates to polyetheramide acid and polyetherimide compositions having terminal aliphatically unsaturated end groups. Prior to the present invention, as shown by Heath et al U.S. Pat. No. 3,847,867, assigned to the same assignee as the present invention, polyetherimides were provided by effecting reaction between certain aromatic bis(etheranhydride) and organic diamine. The polyetherimides could be reinforced with fillers to produce high performance composites. The polyetherimides of Heath et al have valuable flow characteristics as distinguished from conventional polyimides which are intractable upon conversion to the polyimide state. However, in particular applications requiring toughness and the ability to form a thermoset as distinguished from a thermoplastic, the polyetherimides of Heath et al do not possess the required chemical functionality which are often needed in making high strength composites or tough flexible films.
Attempts to achieve a suitable balance in processability and good mechanical properties in polyimides are shown by Lubowitz U.S. Pat. Nos. 3,528,950 and 3,781,241, based on the use of organic dianhydrides, such as benzophenone tetracarboxylic acid dianhydride and organic diamine, such as methylene dianiline in combination with specific endcapping monoanhydrides. An additional effort is shown by Winter U.S. Pat. No. 3,842,143 based on the use of amine terminated polyimides in combination with reactive polyolefinic compounds. According to Winter, the polyolefinic compounds were separately synthesized and when added to the amine terminated polyimide, there was effected a lowering of the softening temperature. The various procedures provided by the prior art to make processable thermosetting polyimides were often based on complicated synthetic techniques and the resulting thermosets were often deficient in ease of processability.


The present disclosure relates to a funnel apparatus for channeling cells onto a plurality of distinct, closely spaced regions of a seeding surface. The funnel apparatus has a body portion having an upper surface and a lower surface. The body portion forms a plurality of flow paths, at least one of which is shaped to have a decreasing cross-sectional area from the upper surface to the lower surface. The flow paths are formed at the lower surface to enable cells deposited into the flow paths at the upper surface of the funnel apparatus to be channeled into a plurality of distinct, closely spaced regions on the seeding surface positioned adjacent the lower surface.

This section provides background information related to the present disclosure which is not necessarily prior art.
A current limitation in biology, biomedical engineering, and related fields is an inability during seeding on a growth surface to segregate populations of varying cell types, as well as selectively placing cells only in specific areas, without the use of chemical or permanent physical surface modifications.
Using arrays of micropatterned wells, groups have been able to separate individual cells into physical compartments (see, e.g., Jacqueline R. Rettig and Albert Folch, Large-Scale Single-Cell Trapping And Imaging Using Microwell Arrays, Analytical Chemistry, 77 (17), 2005, 5628-5634) or several cells into physical compartments (see, e.g., Jeffrey C. Mohr, Juan J. de Pablo, Sean P. Palecek, 3-D Microwell Culture of Human Embryonic Stem Cells, Biomaterials, 27 (36), 2006, 6032-6042). These methods are beneficial in that they are capable of separating cells into very small populations, however they have no means of sorting different types of cells into specific wells. And since the wells "trap" the cells within physical barriers, growth and motility of the cells are restricted.
A more improved version of this technology uses micropatterned "holes" in Polydimethylsiloxane (PDMS) or another elastomeric polymer, which is laid on top of a growth substrate before cell seeding. The cells are deposited onto the array of holes such that they land and attach on the substrate, then the PDMS hole array is removed, leaving the cells patterned only in areas where the holes extended to the substrate (see, Emanuele Ostuni, Ravi Kane, Christopher S. Chen, Donald E. Ingber, and, and George M. Whitesides, Patterning Mammalian Cells Using Elastomeric Membranes, Langmuir 16 (20), 2000, 7811-7819). This allows the cells to grow freely on an unconfined surface, however it does not provide a means for seeding multiple cell types simultaneously. Other groups have used microcontact printing and other methods to pattern cell-adhesive chemicals and proteins onto substrates, causing cells to only attach to those regions containing the chemical (see Ravi S Kane, Shuichi Takayama, Emanuele Ostuni, Donald E Ingber, George M Whitesides, Patterning Proteins and Cells Using Soft Lithography, Biomaterials, 20 (23-24), 1999, 2363-2376). Though this allows cells to grow freely on a flat surface, the surface has been modified chemically in specific areas, causing potential variation in how the cell population grows, migrates, and proliferates. It is possible to have different cell types attach to certain areas by patterning chemicals that interact preferentially with certain cells. However, many of the chemicals or proteins used in this approach interact favorably with many types of cells. This is especially true if the cell populations used are from the same organ (e.g., the brain or spinal cord).
This invention addresses all of the aforementioned shortcomings in a relatively simple and easy to use design. The proposed funnel design allows for multiple cell types to easily be seeded into macroscale openings at the top of the device, then the openings narrow substantially such that the cells land on the surface separated by distances as small as several microns. Once the cells attach, the funnel is removed, producing a flat, unmodified surface with cells of one or more types localized to specific regions of the substrate.

Funnel for localizing biological cell placement and arrangement

Lawrence Livermore National Security, LLC


Assays employing fibronectin-depleted substrates are described to identify invasion inducing agents. Such agents are useful for in vivo wound healing, including but not limited to deep wounds and chronic wounds.

The present invention relates to methods and compositions for wound healing, and in particular, methods and compositions to promote and enhance wound healing.
The primary goal in the treatment of wounds is to achieve wound closure. Open cutaneous wounds represent one major category of wounds and include bum wounds, neuropathic ulcers, pressure sores, venous stasis ulcers, and diabetic ulcers. Open cutaneous wounds routinely heal by a process which comprises six major components: i) inflammation, ii) fibroblast proliferation, iii) blood vessel proliferation, iv) connective tissue synthesis v) epithelialization, and vi) wound contraction. Wound healing is impaired when these components, either individually or as a whole, do not function properly. Numerous factors can affect wound healing, including malnutrition, infection, pharmacological agents (e.g., actinomycin and steroids), diabetes, and advanced age [see Hunt and Goodson in Current Surgical Diagnosis and Treatment (Way; Appleton and Lange), pp. 86-98 (1988)].
With respect to diabetes, it is known that delayed wound healing causes substantial morbidity in patients with diabetes. Diabetes mellitus is a chronic disorder of glucose metabolism and homeostasis that damages many organs. It is the eighth leading cause of death in the United States. M. Harris et al., xe2x80x9cPrevalence of Diabetes and Impaired Glucose Tolerance and Glucose Levels in the US Population aged 20-40 Years,xe2x80x9d Diabetes 36:523 (1987). In persons with diabetes, vascular disease, neuropathy, infections, and recurrent trauma predispose the extremities, especially the foot, to pathologic changes. These pathological changes can ultimately lead to chronic ulceration, which may necessitate amputation.
The most commonly used conventional modality to assist in wound healing involves the use of wound dressings. In the 1960s, a major breakthrough in wound care occurred when it was discovered that wound healing with a moist occlusive dressings was, generally speaking, more effective than the use of dry, non-occlusive dressings [Winter, Nature 193:293-94 (1962)]. Today, numerous types of dressings are routinely used, including films (e.g., polyurethane films), hydrocolloids (hydrophilic colloidal particles bound to polyurethane foam), hydrogels (cross-linked polymers containing about at least 60% water), foams (hydrophilic or hydrophobic), calcium alginates (nonwoven composites of fibers from calcium alginate), and cellophane (cellulose with a plasticizer) [Kannon and Garrett, Dermatol. Surg. 21:583-590 (1995); Davies, Burns 10:94 (1983)]. Unfortunately, certain types of wounds (e.g., diabetic ulcers, pressure sores) and the wounds of certain subjects (e.g., recipients of exogenous corticosteroids) do not heal in a timely manner (or at all) with the use of such dressings.
Several pharmaceutical modalities have also been utilized in an attempt to improve wound healing. For example, treatment regimens involving zinc sulfate have been utilized by some practitioners. However, the efficacy of these regimens has been primarily attributed to their reversal of the effects of sub-normal serum zinc levels (e.g., decreased host resistance and altered intracellular bactericidal activity) [Riley, Am. Fam. Physician 24:107 (1981)]. While other vitamin and mineral deficiencies have also been associated with decreased wound healing (e.g., deficiencies of vitamins A, C and D; and calcium, magnesium, copper, and iron), there is no strong evidence that increasing the serum levels of these substances above their normal levels actually enhances wound healing. Thus, except in very limited circumstances, the promotion of wound healing with these agents has met with little success.
What is needed is a safe, effective, and interactive means for enhancing the healing of wounds. The means should be able to be used without regard to the type of wound or the nature of the patient population to which the subject belongs.
The present invention is directed at systems and methods for enhancing the healing of wounds, especially chronic wounds (e.g., diabetic wounds, pressure sores). The compositions of the present invention are based on the discovery that peptides containing the amino acid sequence PHSRN (SEQ ID NO:1) promote wound healing. The present invention contemplates the use of such peptides, peptide derivatives, protease-resistant peptides, and non-peptide mimetics in the treatment of wounds.
It is not intended that the present invention be limited to the mode by which the compositions of the present invention are introduced to the patient. In one embodiment, the present invention contemplates systemic administration of the compound (e.g., intravenous). In another embodiment, the present invention contemplates topical administration, including but not limited to topical administration using solid supports (such as dressings and other matrices) and medicinal formulations (such as mixtures, suspensions and ointments). In one embodiment, the solid support comprises a biocompatible membrane. In another embodiment, the solid support comprises a wound dressing. In still another embodiment, the solid support comprises a band-aid.
The present invention contemplates a method for treating a wound, comprising a) providing: i) an invasion-inducing agent, and ii) a subject having at least one wound; and b) administering said invasion-inducing agent to said subject under conditions such that the healing of said wound is promoted.
The present invention also contemplates a method for treating a wound, comprising a) providing: i) an invasion-inducing agent on a solid support, and ii) a subject having at least one wound; and b) placing the solid support into the wound of the subject under conditions such that the healing of the wound is promoted.
The present invention also contemplates a method of screening candidate invasion-inducing agents comprising: a) providing: i) inducible cells, ii) a fibronectin-depleted substrate, and iii) one or more candidate invasion-inducing agents, b) contacting said cells in vitro with said fibronectin-free substrate and said one or more candidate invasion-inducing agents; and c) measuring the extent of cell invasion of said substrate. It is not intended that the present invention be limited to the type of inducible cells. In one embodiment, said inducible cells are epithelial cells. In another embodiment, said inducible cells are selected from the group consisting of fibroblasts, keratinocytes and muscle cells.
It is also not intended that the present invention be limited to a particular invasion-inducing agent. In one embodiment, said invasion-inducing agent comprises a fibronectin-derived peptide. In a preferred embodiment, said peptide comprises the amino acid sequence PHSRN (SEQ ID NO:1). In yet another embodiment, said peptide lacks the RGD motif. In yet another embodiment, said peptide lacks the motif which binds the xcex15xcex21 receptor.
It is not intended that the present invention be limited by the length of the peptide. In one embodiment, said peptide is between five and five hundred amino acids in length. In a preferred embodiment, said peptide comprises the amino acids PHSRN (SEQ ID NO:1) and additional amino acids added to the amino terminus. In another embodiment, said peptide comprises the amino acids PHSRN (SEQ ID NO:1) and additional amino acids added to the carboxy terminus. In yet another embodiment, said peptides comprises the amino acids PHSRN (SEQ ID NO:1) and additional amino acids added to both the amino and carboxy termini.
It is not intended that the present invention be limited to specific invasion-inducing agents. In one embodiment, the present invention contemplates invasion-inducing agents that comprise peptides that are protease resistant. In one embodiment, such protease-resistant peptides are peptides comprising protecting groups. In a preferred embodiment, endoprotease-resistance is achieved using peptides which comprise at least one D-amino acid.
To facilitate understanding of the invention set forth in the disclosure that follows, a number of terms are defined below.
The term xe2x80x9cwoundxe2x80x9d refers broadly to injuries to the skin and subcutaneous tissue initiated in different ways (e.g., pressure sores from extended bed rest and wounds induced by trauma) and with varying characteristics. Wounds may be classified into one of four grades depending on the depth of the wound: i) Grade I: wounds limited to the epithelium; ii) Grade II: wounds extending into the dermis; iii) Grade III: wounds extending into the subcutaneous tissue; and iv) Grade IV (or full-thickness wounds): wounds wherein bones are exposed (e.g., a bony pressure point such as the greater trochanter or the sacrum). The term xe2x80x9cpartial thickness woundxe2x80x9d refers to wounds that encompass Grades I-III; examples of partial thickness wounds include burn wounds, pressure sores, venous stasis ulcers, and diabetic ulcers. The term xe2x80x9cdeep woundxe2x80x9d is meant to include both Grade III and Grade IV wounds. The present invention contemplates treating all wound types, including deep wounds and chronic wounds.
The term xe2x80x9cchronic woundxe2x80x9d refers to a wound that has not healed within 30 days.
The phrase xe2x80x9cpositioning the solid support in or on the woundxe2x80x9d is intended to mean contacting some part of the wound with the solid support.
The phrases xe2x80x9cpromote wound healing,xe2x80x9d xe2x80x9cenhance wound healing,xe2x80x9d and the like refer to either the induction of the formation of granulation tissue of wound contraction and/or the induction of epithelialization (i.e., the generation of new cells in the epithelium). Wound healing is conveniently measured by decreasing wound area.
The phrase xe2x80x9cwound fluid contentsxe2x80x9d refers to liquid associated with a wound, as well as cells, cell factors, ions, macromolecules and protein material suspended such liquid at the wound site.
The term xe2x80x9csubjectxe2x80x9d refers to both humans and animals.
The terms xe2x80x9cenclosure,xe2x80x9d xe2x80x9ccompartment,xe2x80x9d and the like refer broadly to any container capable of confining a solid support within a defined location.
The term xe2x80x9csolid supportxe2x80x9d refers broadly to any support, including, but not limited to, microcarrier beads, gels, Band-Aids(trademark) and dressings.
The term xe2x80x9cdressingxe2x80x9d refers broadly to any material applied to a wound for protection, absorbance, drainage, etc. Thus, adsorbent and absorbent materials are specifically contemplated as a solid support. Numerous types of dressings are commercially available, including films (e.g., polyurethane films), hydrocolloids (hydrophilic colloidal particles bound to polyurethane foam), hydrogels (cross-linked polymers containing about at least 60% water), foams (hydrophilic or hydrophobic), calcium alginates (nonwoven composites of fibers from calcium alginate), and cellophane (cellulose with a plasticizer) [Kannon and Garrett, Dermatol. Surg. 21:583-590 (1995); Davies, Burns 10:94 (1983)]. The present invention specifically contemplates the use of dressings impregnated with the wound healing promoting and enhancing compounds of the present invention.
The term xe2x80x9cbiocompatiblexe2x80x9d means that there is minimal (i.e., no significant difference is seen compared to a control), if any, effect on the surroundings. For example, in some embodiments of the present invention, the dressing comprises a biocompatible membrane.
The term xe2x80x9cpeptide derivativexe2x80x9d refers to compound having an imino group (xe2x80x94NHxe2x80x94), and more particularly, a peptide bond. Peptides may be regared as substituted amides. Like the amide group, the peptide bond shows a high degree of resonance stabilization. The Cxe2x80x94N single bond in the peptide linkage has typically about 40 percent double-bond character and the Cxe2x95x90O double bond about 40 percent single-bond character.
xe2x80x9cProtecting groupsxe2x80x9d are those groups which prevent undesirable reactions (such as proteolysis) involving unprotected functional groups. In one embodiment, the present invention contemplates that the protecting group is an acyl or an amide. In one embodiment, the acyl is acetate. In another embodiment, the protecting group is a benzyl group. In another embodiment, the protecting group is a benzoyl group. The present invention also contemplates combinations of such protecting groups.
The term xe2x80x9cBand-Aid(trademark)xe2x80x9d is meant to indicate a relatively small adhesive strip comprising and adsorbent pad (such as a gauze pad) for covering minor wounds.

Methods and compositions for wound healing

The Regents of the University of Michigan


A device for attaching materials to remote bodies, such as tree limbs or overhead wires is disclosed. The device has an elongated body with a first and second end. A clamping system capable of slidably affixing a fastener and attached material is attached to the elongated body first end. A method for attaching materials to remote bodies also is disclosed.

The problem of attaching or removing materials from physically remote bodies, such as tree limbs or overhead wires is well known. There are a number of ways to approach this problem, especially when the tree limb or overhead wire is outside of hand's reach. One approach to the problem is to use a ladder or some mechanism which actually raises the person doing the work to the level necessary to allow them to attach the material to the desired body.
In general, a more satisfactory approach for simpler attachments has been to use a mechanism that effectively extends the reach of an individual by using a device which allows the individual to stand at ground level and reach out to the remote body. These devices have been used, and while an improvement over physically moving individual workers, frequently these devices have a number of moving parts which can make them expensive to manufacture, and cause some difficulties in maintenance. Also, a number of these devices which involve remotely operatable fingers, etc. can be difficult for an operator to master and use efficiently.
Additional problems are encountered when the remote body which is to have the material attached to it is sensitive to damage, such as a plant. Plant limbs, and some nonorganic bodies, can be very sensitive and susceptible to damage, especially if the manner in which the materials are attached to them damages an outer covering or bark. A number of methods using spring clamps to attach materials around electrical wiring or hooks to remove materials clamped to wires or ropes, etc. are unworkable for the use of attaching or removing materials from more fragile bodies, such as young fruit trees.
As illustrated by the above discussion, there are a number of desireable features for a device or apparatus for attaching materials to remote bodies, such as overhead wires or tree limbs. It would be desireable to have a device which allowed one to attach the material to a remote body such as a tree limb without requiring that the operator be removed from the ground. It would be desireable to have a device to attach materials to a remote body that is mechanically simple, to minimize or eliminate moving parts to reduce the cost of production. Further, it would be desireable to have a device to attach materials to a remote body such as a tree limb which is straight-forward to operate. In addition, it would be desireable to have a device to attach materials to a remote body such as a tree limb which would not damage the body to which the materials were attached. It also would be desireable to have a device for attaching materials to a remote body, such as a tree limb, which could be stored compactly when not in use.
While the discussion herein relates to devices and methods for attaching materials to remote bodies such as tree limbs, it is not intended that the invention be limited to this situation. It will be obvious from the description that follows that the present invention will be useful in other applications with problems common to those described herein.

Device for attaching materials to tree limbs


The present invention relates to display means for systems for guiding a trailer while backing, and in particular to graphical display means to provide information to an operator who is steering, and controlling the accelerator and breaks by suggesting the amount of steering to apply to the towing vehicle to cause the trailer to be directed to where the operator wants the trailer to go.

Trailers have been around for many years, yet every summer and winter one can observe the owners of boats and snowmobiles, respectively, backing up those devices on trailers with great difficulty. The problem arises from the fact that a trailer being backed-up is an inherently unstable system. A trailer being pushed wants to turn around and be pulled (i.e., to jackknife) instead. To compensate for this instability, the driver must skillfully alternate the direction of his steering so as to cause the trailer to want to turn around and be pulled from opposite sides thereby repeatedly crossing the centerline of the pushing vehicle. Various innovations have been introduced to address this problem in whole or in part. Prior art reveals several attempts to address the problems associated with backing a trailer. The simplest solutions address parts of the problem ranging from ways of sensing the angle of the hitch (see: Kollitz, U.S. Pat. No. 4,122,390), to sensing and displaying the angle of the hitch (see: Gavit, U.S. Pat. No. 3,833,928), to sounding an alarm when a jackknife condition exists or is imminent (see: Kimmel, U.S. Pat. No. 4,040,006). While these solutions are helpful, they only each address a part of the backing problem. Shepard in his U.S. Pat. No. 7,715,953 teaches a complete working system. However, in that teaching, some new needs arise that are addressed by the teaching of the present invention, such as how to install a complete working system as an after market product that can easily be installed or removed and how to install a sensor for measuring the angle formed between the centerline of the vehicle and the centerline of the trailer (i.e., the hitch angle sensor or, as it is sometimes also known, the articulation angle sensor) such that it does not interfere or collide with the trailer tongue or any other parts of the hitching system. In particular, an angle sensor is needed that can get its measurement in-line with the axis of rotation of the trailer tongue upon the hitch ball (i.e., to measure the articulation angle of this hitch joint) without actually being located at that axis of rotation. This hitch angle sensor, in particular, must be designed not to be damaged either during hitching up a trailer (due to a collision between the hitch and sensor with a part of the trailer) nor while towing on the highway (due to kicked up debris).
Trailer guidance systems such as the portable system disclosed in U.S. Patent Application 62/020,526, by Shepard titled "PORTABLE TRAILER GUIDANCE SYSTEM" that was filed on Jul. 9, 2014 require sensors for detecting the hitch angle and the turning radius and output means for displaying the intended trailer destination. Most vehicles do not have integral turning sensors and most trailers and/or hitches do not have integral hitch angle sensors. A solution is to make a hitch angle sensor that can be added to an existing vehicle that did not have such capability leaving the automotive assembly line. Once such an investment in a hitch angle measurement sensor is made, it is possible to leverage this sensor for not only measuring the angle of the hitch, but to also adapt the angle measuring mechanism of the hitch angle sensor to create a guidance mechanism to assist a driver in backing up the vehicle in order to couple the vehicle to the trailer.


Antimicrobial and anticancer peptides engineered using Gaegurin 5 isolated from Korean frog (Rana rugosa), which have a smaller structure compared with previously known Gaegurin peptides and show potent antimicrobial and anticancer activity. Specifically, the antimicrobial and anticancer peptides synthesized from the shortest length of Gaegurin 5, show potent antimicrobial activity against gram positive and negative strains, good safety with very low hemolytic activity and favorable advantages such as drug absorption and drug transportation due to its advantageous structural property, which can be useful as a potent antimicrobial or anticancer agent.

Antimicrobial peptides acting on cellular membranes have been found in most of the species in the world. Recently, researchers have paid attention to antimicrobial peptides to overcome the problems of conventional antibiotics, i.e., the increase of antibiotic resistant bacteria. Especially, after the first finding of bombinins from Bombina variegate in 1969, the skin of anurans (frogs and toads) has proven to be a rich source of antimicrobial peptides, which have a broad-spectrum of antimicrobial activities. After the discovery of an antimicrobial peptide from the African toenail frog, i.e., magainins in 1987, the antimicrobial peptides from frog skin has been a focus for potential therapeutic agents.
Since antimicrobial peptides kill bacteria by acting on the bacteria cell membrane and destroying the membrane selectively, the mechanism of an antimicrobial peptide is quite different from that of the existing antibiotics and is valuable as an alternative method for overcoming resistance problems. Furthermore, since the antimicrobial peptides have a broad spectrum of antimicrobial activity against gram-positive microbes, gram-negative microbes, fungi, viri and tumor cells, a natural substance isolated from a natural resource is expected to be a good antibiotic showing no side effects. Additionally, since it shows amphipathic properties, i.e., soluble in both water and lipid, it is expected to have great advantages in respect to drug absorption, drug transportation, etc. However, in spite of the favorable advantages of antimicrobial peptides, there remain several problems, such as, structural stability, bulky M. W., etc; in developing an antimicrobial peptide as a drug. The big problems of antimicrobial antibiotics are stability and molecular weight, as follows. First, in respect to stability, the antimicrobial peptides are easily decomposed due to great quantities of protein lyases existing in vivo. These problems can be solved by introducing unnatural derived amino acids, such as, D-amino acid, beta-amino acid, modifying their chemical structures and similar techniques. However, another problem, i.e., the bulky size of antimicrobial peptides having molecular weights greater than 3,000 still remains to be solved to correct the problems in respect to drug absorption, drug transportation, etc.
Anticancer agents can be classified into three categories, i.e., a bio-engineered drug, such as, anticancer drugs using gene, enzyme, vaccine etc; a synthesized drug and a natural product-derived drug. However, there remain several problems, for example, most bio-engineered drugs have not been developed in a clinical anticancer agent; and many chemotherapeutic agents have diverse pharmacological mechanism in accordance with the type of cancer (Gillman et al., The pharmacological Basis of therapeutics, Maxwell Macmillan., 18, p 1202, 1986) and toxic side effects (Chung et al., J. Wonkwang Medical ScL, 3, pp 13-34, 1987). Specifically, anticancer agents show toxic effects not only on cancer cells but also on normal cells. Also, there is resistance to anticancer agents caused by several factors, i.e., the mutation during growth, proliferation and metastasis of cancer cells. Since most anticancer agents have molecular weights less than 1,000 Dalton, the administered anticancer agents were absorbed in cancer cells, as well as, normal tissue resulting in damage to normal cells, especially, actively cell-dividing normal cells, for example, dysfunction of bone marrow, gastrointestinal disorders, alopecia, etc. Due to the low molecular weight, it is easily excreted through urine and therefore a great amount of an agent is required to obtain a desirable medical effect.
Therefore, the present inventors have endeavored to overcome the previously reported problems of antibiotic peptides and anticancer agents, and experimented to find effective and novel peptides showing more a potent efficacy than previously reported. Finally, they have found that novel synthesized analogues based on Gaegurin 5, the smallest length among six kinds of antimicrobial peptides previously designated as Gaegurin isolated from Korean frog, i.e., Gaegurins 1 to 6, showed potent antimicrobial, anticancer and non-hemolytic activity.

Analogues of antimicrobial and anticancer peptide synthesized and produced from Gaegurin 5


A dental handpiece is disclosed, which includes a burr sleeve, upper and lower ball bearings for rotatably supporting the burr sleeve, a rotor fixed to the burr sleeve between the upper and lower ball bearings and rotated for rotatably driving the burr sleeve, and a dust controller. The dust controller includes a rotary protruding member fixed on the outer surface of the burr sleeve and rotating integrally with the burr sleeve, and a stationary protruding member attached to a stationary part of the handpiece and having a surface facing to the rotary protruding member to define a gap therebetween located outside of the lower ball bearing. The upper and lower ball bearings are angular contact ball bearings each having a bearing cage. The bearing cage has apertures that support bearing balls therein and are located in the middle of the bearing cage in the thrust direction.

The present invention relates to a dental handpiece, in particular a dental handpiece having angular contact ball bearings.
Conventional dental handpieces having angular contact ball bearings have a general structure as shown in FIG. 3, in which head housing 11 accommodates burr sleeve 13, rotor 16, and ball bearings 34, 35. The burr sleeve 13 detachably holds a dental treatment tool 9 therein, and is rotatably supported by the upper and lower bearings 34, 35. The rotor 16 is fixed to the burr sleeve 13 between the upper and lower ball bearings 34, 35, and rotated by compressed air for rotatably driving the burr sleeve 13. The head housing 11 is capped with head cap 18, which is provided with spring 17 and push button 19, and screwed into the head housing 11.
The upper and lower bearings 34, 35 are of the angular contact type, wherein the groove on the outer rings 34b, 35b, i.e. the outer race, is tapered or angled. To each of the outer rings 34b, 35b is attached shield cover 37 using retaining ring 36 for preventing dust, such as debris, from intruding into the bearing. A plurality of balls 34c, 35c are supported at regular circumferential intervals by bearing cages 34d, 35d. The bearing cages 34d, 35d are in the form of a ring having a plurality of pockets 34e, 35e for supporting the balls 34c, 35c therein, as shown in FIGS. 4(a) and 4(b) in side and cross sectional views, respectively.
In the conventional dental handpieces as discussed above, the shield covers 37 interposed between the inner 34a, 35a and outer rings 34b, 35b restrict the spaces available for the bearing cages 34d, 35d. In order to be adapted to this restricted spaces, portions 34dxe2x80x2, 35dxe2x80x2(FIGS. 4(a) and 4(b)) of the cages 34d, 35d facing to the shield covers 37 have to be made smaller, resulting in difference in size between the portions above and below the pockets 34e, 35e of the bearing cages 34d, 35d.
Due to such asymmetry, when the burr sleeve 13 is rotated, the bearing cages 34d, 35d become unstable and contact the balls 34c, 35c, rattling up and down. This causes abrasion and wearing of the balls 34c, 35c and bearing cages 34d, 35d to damage these parts, and also causes undesirable shaking of the handpiece to generate uncomfortable noise.
The asymmetrical bearing cages 34d, 35d also add to the manufacturing cost of the dental handpiece. In automated assembly of the ball bearings 34, 35, the orientation of the retainers 34d, 35d has to be adjusted as predetermined by the vertically asymmetrical nature of the bearing cages 34d, 35d, which requires special systems and steps.
The present invention has been made to overcome these drawbacks of the conventional dental handpieces. It is therefore an object of the present invention to provide a dental handpiece wherein abrasion and wearing the balls and bearing cages in ball bearings are minimized.
It is another object of the present invention to provide a dental handpiece of which manufacturing cost is suppressed.
It is another object of the present invention to provide a dental handpiece having angular contact ball bearing wherein intrusion of duct into the bearings are effectively prevented.
According to the present invention, there is provided a dental handpiece comprising:
a burr sleeve for detachably holding a dental treatment tool therein;
upper and lower ball bearings for rotatably supporting said burr sleeve;
a rotor fixed to said burr sleeve between said upper and lower ball bearings and rotated by compressed air for rotatably driving said burr sleeve; and
a dust controller including a rotary protruding member fixed on an outer surface of said burr sleeve and rotating integrally with said burr sleeve, and a stationary protruding member attached to a stationary part of said handpiece and having a surface facing to said rotary protruding member to define a gap therebetween, said gap being located outside of said lower ball bearing;
wherein said upper and lower ball bearings are angular contact ball bearings each having a bearing cage, said bearing cage having apertures for supporting balls of said ball bearings therein, said apertures being located substantially in the middle of said bearing cage in a thrust direction.
According to one aspect of the present invention, the conventional shield cover interposed between the inner and outer rings of a ball bearing of conventional dental handpieces is dispensed with, and instead a dust controller is placed outside of the ball bearing to expand the space between the inner and outer rings available for a bearing cage. This expanded space allows a vertically symmetrical bearing cage, i.e., a bearing cage having ball pockets substantially in the middle in the thrust direction, to be disposed between the inner and outer rings of the bearing. This vertically symmetrical bearing cage exhibits improved stability upon rotation of the burr sleeve, and thus minimizes shaking and noise of the handpiece. Further, use of the vertically symmetrical bearing cage eliminates special systems and steps for adjusting the vertical orientation of the bearing cage in automated assembly of the ball bearings, which reduces manufacturing cost of the handpiece.
According to another aspect of the present invention, a dental handpiece having an air turbine wherein a burr sleeve is rotated with compressed air, is provided with a dust controller including a rotary protruding member and a stationary protruding member. The rotary protruding member is fixed on and protrudes from the outer surface of the burr sleeve, and is rotated integrally therewith. The stationary protruding member is attached to and protrudes from a stationary part of the handpiece, and has a surface facing to the rotary protruding member to define a gap therebetween. The gap is located outside of the ball bearing.
The interior of the lower ball bearing communicates with the outside of the head housing via the dust controller. Rotation of the dust controller creates a high-pressure region between the rotation space of the rotor and the outside of the head housing. This high pressure region effectively blocks off air flow out of the head housing, and prevents suction of debris, saliva, blood, and the like through the lower end of the head housing upon stopping of the rotation of the rotor, which creates negative pressure in the head housing during rotation.
In the present invention, the stationary protruding member may be of any shape and configuration, as long as it does not narrow the space between the inner and outer rings of the ball bearing, and has a surface facing to the rotary protruding member to define a gap therebetween, which gap is located outside of the lower ball bearing. For example, the stationary protruding member may be generally in the form of an annular ring, of which radially outer end portion is fixed to the outer ring of the ball bearing, and of which radially inner end portion is extended radially inwardly beyond the inner ring of the ball bearing and defines a surface that faces to the rotary protruding member with a gap formed therebetween. The stationary protruding member may be attached to any stationary part of the handpiece, for example, to the outer ring of the ball bearing.

Dental handpiece with angular contact ball bearings


The present disclosure includes gateways and methods for node selection of virtual network nodes in virtual evolved packet core networks. The methods include receiving, at a gateway from an evolved Node B (eNodeB), an attach request for a user equipment (UE), and determining a network selection hint corresponding to the received attach request, where the network selection hint is used for determining a virtual network node for selection in a mobile cloud network. The methods further include determining a domain name for establishing a network connection based at least in part on the network selection hint, where the selected domain name is associated with a virtual network node in the mobile cloud network. The methods also include selecting a virtual network node associated with the determined domain name, and establishing a network session to the selected virtual network node.

Wireless networks are telecommunications networks that use radio waves to carry information from one node in the network to one or more receiving nodes in the network. Cellular telephony is characterized by the use of radio cells that provide radio coverage for a regional or geographic area, with multiple cells arranged to provide contiguous radio coverage over a larger regional or geographic area. Wired communication can also be used in portions of a wireless network, such as between cells or access points.
Wireless communication technologies are used in connection with many applications, including, for example, satellite communications systems, portable digital assistants (PDAs), laptop computers, and mobile devices (e.g., cellular telephones, user equipment). Users of such devices can connect to a network (e.g., the Internet). When these devices initially connect to a network, gateways in the network select downstream network nodes for establishing network connections or network sessions with the devices.

Node selection in virtual evolved packet core


Core barrel apparatus for obtaining and retrieving sealed core samples of subterranean formations are disclosed. The core barrel comprises a sample chamber for receiving a core sample as it is formed at the bottom of a bore hole and an expansion chamber for receiving sample fluids. The expansion chamber comprises a cylinder having a movable sealing member therein adapted to movably seal the expansion chamber. The volume of the expansion chamber is determined by the position of the sealing member in the cylinder, movement of the sealing member changing the volume of the expansion chamber. The sample chamber and expansion chamber are selectively connected to one another by means of a seal therebetween. The expansion chamber is sealed closed by the sealing member at one end and said seal at the other end while the sample is being cut and received within the sample chamber. Thereafter, the lower portion of the sample chamber is sealed by a flap-valve and the expansion chamber is opened to the sample chamber. The movable sealing member moves during ascent to expand the expansion chamber and reduce the pressure therein. A cup-like member, a piston, a spheroidal member, and a bellows member are disclosed to be embodiments of the movable sealing member. Valving is provided in the sample and expansion chambers so that the chambers may be individually sealed and separated, and sample fluids removed from the chambers through the respective valves.

1. Field of the Invention
The invention relates to core barrel apparatus for obtaining and retrieving sealed samples of subterranean formations and, more particularly, to expansion chambers and valves thereof.
2. Description of the Prior Art
In the art of obtaining samples of subterranean formations it is well known to lower a coring device or other formation sampling apparatus into a well bore while suspended by a cable, a wire line, or a drill string. It is desired that not only the solid core sample but also any fluids present therein be recovered and brought to the surface. Retaining fluids in the sampling apparatus, particularly the compressible gaseous fluids, is difficult and unreliable due to the extreme pressure differential between the sealed interior of the apparatus, in which is present the greatly elevated formation pressure at the bottom of the bore hole, and the ambient atmospheric pressure when the sampling apparatus is brought to the surface. This pressure differential varies as a function of the depth of the bore hole; however it is not uncommonly in the range of about 5,000-11,000 pounds per square inch.
Some known core barrel devices and sampling methods seal the sample at the formation pressure in a fluid-tight chamber which is capable of withstanding a high internal pressure while maintaining a fluid-tight seal as the sample is brought to the surface. Such fluid-tight chambers are provided with extremely strong and reliable seals, walls, etc. and yet are still prone to leak. Use of such chambers presents a safety hazard in that the high pressure within the chamber makes the sampling device difficult and perhaps even dangerous to handle, particularly when moving the chamber or attempting to withdraw the fluid and solid samples from the chamber.
It has been disclosed in U.S. Pat. No. 2,287,909, issued on June 30, 1942 to B. W. Sewell, that the pressure differential may be reduced by providing an expandable volume within the sampling apparatus into which volume the gases may expand to reduce the pressure differential. The sampling apparatus of the Sewell patent may not be adaptable for conditions encountered in comparatively deep bore holes due to the size of the expansion chamber shown in the Sewell '909 patent. By way of example, the bottom hole conditions in a bore hole of approximately 10,000 feet in depth could be from about 5,000-11,000 psig and 200.degree. F. Gas or vapor under such bottom hole conditions is of a density that will cause it to expand from approximately 200-400 times in volume when elevated to surface conditions. Further by way of example, if the core sample to be taken is approximately 4 inches in diameter and 20 feet in length and if the rock sample is 20% porous with half of the porous region occupied by gas, the gas could expand to approximately 70 cubic feet when elevated to surface conditions. Accordingly, a sampling apparatus for a deep bore hole must be provided with an expansion chamber capable of expanding to an appreciable volume. Furthermore, the apparatus disclosed in the Sewell '909 patent does not provide a selectively closed expansion chamber which may be sealed from drilling fluid and other substances as the device is lowered in the well bore and as a sample is taken. Thus, the chamber of the Sewell '909 patent may become filled with drilling fluid or other unwanted substances as the core sample is being obtained. Receiving drilling fluid or other substances in the expansion chamber of the device of the Sewell '909 patent not only can detract from the usefulness of the formation sample but also volume in the chamber is occupied which could otherwise provide additional volume for gaseous components of the sample as they expand. Additionally, the chamber in which the sample is received and the expansion chamber of the Sewell '909 patent may not be individually sealed and separated.
It is apparently unknown in the prior art to maintain a sample chamber sealed or closed until opened at the bottom of a bore hole and to expand the sample chamber in response to the gases therein as the sample is brought to the surface.
The present invention overcomes the aforementioned drawbacks and disadvantages of the prior art and provides additional advantages as well.

Core barrel for obtaining and retrieving subterranean formation samples


A hand-held instrument for performing a cholangiogram during a laparoscopic surgical procedure is disclosed. The instrument includes a pistol-shaped housing having a cannula mounted at a forward end. Centrally located within the cannula and extending into the housing is a hollow catheter. Mounted within the housing are an advancing mechanism, a locking mechanism, and an injection system. The advancing mechanism incrementally extends the catheter from one end of the cannula and the locking mechanism holds the catheter at the extended position. The injection system expels contrast media from a reservoir within the handle of the housing into the catheter for injection into a cystic duct. Each of the systems within the housing can be independently operated by the hand holding the instrument. The end of the cannula distal from the housing includes a threaded bulge which is rotated by a wheel extending through the housing. Rotation of the wheel screws the threaded bulge into an incision on the cystic duct to facilitate the insertion of the cannula into the duct and to form a watertight seal which prevents leakage at the incision during injection of the contrast media.

Laparoscopic surgery is being used more frequently because it is less intrusive to the patient's body which permits shorter hospital stays. One particular form of surgery which is especially adaptable to laparoscopic surgery is gall bladder removal.
In a typical laparoscopic surgical procedure for removing a gall bladder, short incisions are made through the abdominal wall of the patient for the insertion of the surgical instruments used to perform the surgery. The abdominal cavity is bloated by pumping a gas such as CO.sub.2 into the abdominal cavity to provide the surgeons and their assistants with room to maneuver surgical instruments and a perspective from which a camera inserted into the cavity during the surgery can properly view the internal organs and abdominal wall. For each incision made through the abdominal wall, a trocar is inserted through the incision. The trocar provides a passageway for the surgical instruments through the patient's skin and abdominal wall and prevents the escape of the gas from the cavity during the surgery.
To provide the surgeon with a picture of what is occurring in the abdomen, an incision is made on the patient's umbilicus. After insertion of the trocar, a long laparoscope cylindrical lens of a camera is inserted through the trocar. The camera lens contains a light source to illuminate the organs and the picture generated by the camera is displayed on CRTs placed in the vicinity of the patient's upper body near the table. After viewing the display generated by the camera, the surgeon selects an appropriate spot on the upper right abdominal wall where a second incision is made and a trocar is inserted. This incision is used by a second surgeon or surgical assistant to aid the surgeon during the procedure. A third incision is made on the lower right side through which the second surgeon inserts instruments for assisting in exposing the gall bladder for dissection by the surgeon. The final incision is made in the upper midline (epigastrium) for the operative port through which the surgeon inserts various instruments used in performing the surgery.
To remove the gall bladder, the camera is used to locate adhesions on the abdominal wall which the surgeon removes with scrapping or cutting instruments inserted into the abdominal cavity. The liver is located and lifted to reveal the gall bladder underneath it. The cystic duct which leads into the gall bladder is clamped at a portion away from the gall bladder. The cystic artery is located and clamped to prevent excessive hemorrhaging in the abdominal cavity should a rupture of this artery occur. The gall bladder may be cut or burned loose by a laser. After the hemorrhage sites are cauterized to stop the bleeding, the gall bladder is located and pulled through the operative port in the abdominal wall. The trocars are removed and the incisions sutured. All clips, clamps, and instruments inserted in the abdominal cavity must be accounted by the surgical nurse.
While such a surgical procedure is effective for the removal of the gall bladder, ductal injuries or anatomical anomalies may not be readily discovered during such a surgical procedure. To provide the surgeon with this information during the surgery, a cholangiogram can be performed. A cholangiogram is an x-ray of the common bile duct which can alert the surgeon to previously undiscovered stones, anatomical anomalies which may require careful dissection, and ductal injuries which may lead to later complications following the gall bladder removal. If the cholangiogram is performed while the surgery is in process, the surgeon may remove the stones immediately and reduce the chance of post-operation common bile duct obstruction.
To perform a cholangiogram, a pair of micro-scissors are inserted into the abdominal cavity to dissect the cystic duct at a point between the gall bladder and where it is clamped. The micro-scissors are then removed. The surgeon inserts a gripping tool through a trocar while a nurse brings a tube leading from a syringe filled with contrast media into proximity with the cystic duct. At the forward end of the tube is mounted a cannula with a concentrically located catheter. The surgeon grips the end of the catheter extending from the cannula with the gripping tool and inserts it into the incision made by the micro-scissors. Using the inserted portion of the catheter as a guide wire, a portion of the cannula is inserted into the cystic duct. A clip is placed around the cannula and cystic duct to prevent leakage when the contrast media is injected.
At this point, all medical personnel except the surgeon and a technician leave the operating room. The technician places an x-ray film cassette under the patient's back and brings a mobile x-ray unit with a flexible C-arm over the patient's abdomen in the vicinity of the gall bladder. The surgeon then injects the contrast media through the tubing and catheter into the cystic duct which leads to the gall bladder. As the contrast media is injected, the technician takes a cholangiogram. After the technician has replaced the cassette with another one, the surgeon begins another injection so the technician can take a second cholangiogram. The technician removes the mobile x-ray machine and the other members of the operating team return.
The surgeon removes the clip from around the cannula and grips the cannula to remove it and then the catheter is withdrawn from the cystic duct. The nurse removes the tubing from the patient's abdomen through a trocar and the surgical procedure may proceed. The technician develops the cholangiograms and returns to the operating room to display them on light tables in the operating room. The surgeons may view them to ascertain if any additional surgical procedures are necessary.
While the information produced from a cholangiogram is important and useful to surgeons, very few surgeons conducting laparoscopic gall bladder removals regularly take them. This reluctance arises from the difficulties encountered in performing the procedure for taking cholangiograms. Most of the problems stem from the coordination required between the surgical team members to grasp and insert the catheter into the small incision in the cystic duct. This cooperation between team members is not only difficult because they must view the CRT to coordinate their instrument movements within the abdominal cavity, but they must manipulate articles that are very small. The diameter of the catheter is smaller than fish line and the incision in the cystic duct is correspondingly tiny. Such a procedure is roughly comparable to two people attempting to thread a needle by using barbecue tongs to hold the needle and thread. In some cases, inserting the catheter into the cystic duct through the small incision may take 30 minutes or longer. Such a time interval almost doubles the time necessary for the removal of a gall bladder.
What is needed is an expeditious method for performing a cholangiogram during a laparoscopic surgical procedure. What are also needed are instruments with which the surgical personnel can better coordinate their interactions to perform the cholangiogram.

Catheter device for performing a cholangiogram during a laparoscopy surgery


An airfoil diffuser for a centrifugal compressor formed by a diffuser passage area and a plurality of diffuser blades located within the diffuser passage area. The diffuser passage area is defined between a hub plate and a shroud of the centrifugal compressor. Each of the diffuser blades has a twisted configuration in a stacking direction as taken between the hub plate and an outer portion of the shroud located opposite to the hub plate. As a result of the twisted configuration, the diffuser blade inlet blade angle decreases from the hub plate to the outer portion of the shroud and solidity measurements at leading edges of the diffuser plates vary between a lower solidity value measured at the hub plate of less than 1.0 and a high solidity value measured at the outer portion of the shroud of no less than 1.0.

Centrifugal compressors are utilized in a number of industrial applications. The major components of a centrifugal compressor are the impeller which is driven by a power source, typically an electric motor. The impeller rotates within an inner annular region of a hub plate and adjacent to a shroud. The impeller is a rotating bladed element that draws the fluid to be compressed through the shroud and redirects the flow at high velocity and therefore kinetic energy in a direction that is generally radial to the direction of rotation of the impeller. A diffuser is located downstream of the impeller within a diffuser passage area defined between the hub plate and an outer portion of the shroud to recover the pressure in the gas by decreasing the velocity of the fluid to be compressed. The resulting pressurized fluid is directed towards an outlet of the compressor.
In vaneless diffusers, the diffuser passage area between the hub plate and the outer portion of the shroud is ever increasing to recover the pressure. In vane-type diffusers, blades are connected to the hub plate or the outer portion of the shroud in the diffuser passage area. The blades can have a constant transverse cross-section as viewed from hub plate to shroud. In vane-type diffusers, known as airfoil diffusers, the vanes have an airfoil section rather than a constant transverse cross-section.
The power that is required to drive such a centrifugal compressor can represent a considerable portion of the running cost of the plant in which the centrifugal compressor is employed. For example, in an air separation plant, most of the costs involved in operating the plant are electrical power costs used in compressing the air. Compressors employed in such applications as air separation, but other applications as well, require a wide operating range. For example, in an air separation plant, it is necessary to be able to turn down the production and to raise the production. This variable operation can be driven by demand or local electrical power costs which will vary depending on the time of day. However, given the cost of electrical power, it is also necessary that the wide operating range be accompanied by compressor efficiency over the operating range.
In an attempt to increase the operating range while retaining efficiency, it is possible to alter impeller design and diffuser design. With respect to impeller design, however, the actual design employed is constrained by the mechanical arrangement of the compressor and the resulting flow conditions, for instance specific speeds. These arrangements, lead to a predetermination of many of the impeller characteristics, for instance, the design of the impeller shroud and inducer arrangements, axial length and therefore, meridional profile and the use of three-dimensional aerodynamic configurations, namely aerodynamic sweep and lean and the use of splitter blades. Typically, however, the most commonly used impeller characteristic is blade backsweep at the impeller exit. This gives the centrifugal stage a rising pressure characteristic with decreased flow rates which increases the stability of the stage. Furthermore, compared to a radial bladed impeller designed at the same rotation speed and pressure ratio, a backswept impeller has lower blade pressure loading as compared to a radial bladed impeller design, increased impeller reaction and increased loss free energy transfer (Coriolis acceleration) to the fluid.
The diffuser design is less constrained than the impeller. The geometrical constraint for the diffuser design being the size of the volute and collector for overhung stages, or return channel in the case of beam type stages. Vaneless diffusers are able to provide the centrifugal compressor stage with large operating ranges at moderate pressure recovery levels and at moderate efficiencies. Vane-type diffusers, on the other hand, have a higher efficiency level but at reduced ranges. In an attempt to increase the range of operation, U.S. Pat. No. 2,372,880 provides a vane-type diffuser having blades without an airfoil transverse cross-section but with a twist built into the blades to change the throat area and thereby to increase the operating range of the compressor. The resulting diffuser is a high solidity diffuser or in other words geometrically incorporates a ratio, calculated by dividing a distance measured between the leading and trailing edges of the blades by the circumferential spacing between leading edges of adjacent blades, that is greater than 1.0.
Low solidity diffusers, that is airfoil diffusers with a solidity value of less than 1.00 are characterized by the absence of a geometrical throat in the diffuser passage and have proven to possess a large flow range, similar to vaneless diffusers, but at increased pressure recovery levels over vaneless diffusers. The increased range in operation, however, has been found to be at the expense of efficiency compared to high solidity diffusers. At the other extreme, high solidity diffusers have been constructed, that while more efficient, do not possess the operating range of low solidity diffusers.
As will be discussed, in the present invention, in one aspect, provides an airfoil diffuser in which the diffuser blades are fabricated with a twisted configuration that produce a low solidity value at the hub plate and a high solidity value at the shroud with the result that the diffuser imparts to this centrifugal compressor not only a wider operating range but also high efficiency over the wide operating range as compared to the prior art.

Airfoil diffuser for a centrifugal compressor