Topics covered: Biochemistry 1
Instructors: Prof. Robert A. Weinberg
OK. So today we're going to spend a little bit of time on some elementary chemistry just to develop our language that we use with one another. And so when I say hydrogen bond, you don't stare blankly at me and scratch your heads. Many of you have had this already. For many of you this is a review, but it's a useful review. We believe here at MIT of teaching things two or three times often, the same subject matter, but at increasing levels of sophistication.
So I do this without apology. Our first issue here is how are atoms and molecules held together? And the most familiar way by which atoms and molecules are held together is, of course, the covalent bonds. And covalent bonds have an energy of roughly 80 kilocalories per mole.
And that's a rather strong energy to hold together two atoms because the energy, the thermal energy, that is the energy at, let's say, body temperature is about 0.6 kilocalories per mole. And, therefore, if you had a bond, if there was something holding things together that was in this range or two or three or four times higher then the simple thermal energy at room temperature or at body temperature would be sufficient to break apart such a bond.
But, in fact, this energy, the energy of a covalent bond is so much higher that it's highly unlikely that thermal energy is going to break apart a preexisting covalent bond. And I was just reading yesterday about how people were analyzing the mitochondrial DNA from some Neanderthal bones which were dug up. The last Neanderthal lived around 30,000 years ago, our recently demised cousins.
And they were analyzing the DNA sequences. And they got out of those analyses stretches of DNA that were 200, 300 nucleotides long. And that really is stunning testimonial to the fact that under very difficult conditions, nonetheless, complex biological molecules are able to survive over astounding periods of time, indeed those that are held together by the covalent bonds like this.
Of course, you remember the film Jurassic Park where they used PCR reaction to resurrect the DNA of dinosaurs. That's a bit of a fantasy since dinosaurs left us, I guess, about 150 million years ago, something like that. There's a big difference, obviously, between 300,000 and 150 million year ago. Now, the fact is if you look at the way that molecules are actually hooked up, for instance, let's look at a water molecule here.
Ideally there should be no charge on this molecule. And, in fact, there is no net charge. But the truth of the matter is, if one wants to get frank, that oxygen molecules, and we always are here, that oxygen molecules have a greater affinity for electrons than do hydrogen atoms, i.e., they are electronegative. And, therefore, what this means is that the swarms of electrons that are holding all this together at the orbitals are drawn more closely to the oxygen and the hydrogen atoms, i.e., the protons are relatively willing to give up their electrons.
And what this means is that there's an unequal distribution. And, as a consequence, there is a fraction of a negative charge here at this end of the molecule and there are fractions of positive charges here because it's not as if they've totally given up the electrons, but the electrons are shifted more in this direction.
And this molecule is therefore called a polar molecule by virtue of the fact that here it has a positive pole and here it has a negative pole. There are other pairs of molecules which are relatively equally electronegative. For example, here, if we have a carbon and a hydrogen, these two atoms are roughly equally matched in terms of their ability to pull electrons away, one from the other. And, as a consequence, there is no net shifting of charge. And keep in mind that this delta I show here is only a fraction of an electronic charge. It's not the entire electronic charge moved over.
But this has important consequences for the entire biochemistry that we're about to get into both today and on Monday. Important because polar molecules, such as water like this, are able to dissolve certain compounds. And nonpolar molecules, which have large arrays of these kinds of bonds or carbon-carbon bonds, these are relatively insoluble in water, and that has important consequences for the organization of biological membranes.
We might have a carbonyl bond here, that is a C going to an O via a double bond. And here we have, once again, a situation where the oxygen is far more avid in terms of its willingness and interest in pulling electrons toward itself. And, therefore, the carbon gives up a little bit of the electron cloud and it becomes slightly electropositive. Whereas, the oxygen atom becomes slightly electronegative.
Now, the fact of the matter is that there are also other bonds that are noncovalent and are much less energetic. For example, let's talk for a moment about a hydrogen bond. And it's perhaps easiest to demonstrate a hydrogen bond by looking at the structure of two neighboring water molecules in a solution of water of all things.
And, the fact of the matter is, let's say we draw one water molecule down here and one water molecule down here. What will happen is that this oxygen atom over here by virtue of its electronegativity will have a certain affinity for pulling this hydrogen atom toward itself. And, in fact, what actually happens in real life, whatever that is at the molecular level, is that this hydrogen atom may actually be bouncing back and forth between these two oxygens.
It may be rapidly an interchange between them. This interchange causes a strong association between two neighboring water molecules. And, indeed, represents the reason why water does not vaporize at room temperature because the water molecules have a strong affinity or an avidity for one another. And, therefore, just to take some illustrations out of the book, this is the way it's illustrated in the book.
Probably good to have a screen down. And here you can see the way that water molecules are actually arrayed in water. This is the lower illustration here. Just to indicate to you that the hydrogen atoms are not really the possession, the ownership of one molecule of water. They're just constantly being exchanged back and forth. And this back and forth exchange, this sharing of a hydrogen atom is what enables a hydrogen bond of roughly 5 kilocalories of energy per mole to hold things together.
5 kilocalories is not much. It's only one order of magnitude above 0.6 rather than being two orders of magnitude. And, therefore, if one raises the temperature to the level of boiling, if the temperature is high enough, the thermal energy is high enough to rip apart these kinds of associations.
Now, if we were to go back here to look at this carbonyl atom we would find the following sort of situation. Here we have this unequal sharing of electropositive and electronegative bonds. Let's put an acidic group like this. This is a carboxylic acid right here. Here we see a carbon bond to a hydroxyl here via this oxygen atom.
Here, once again, we have an electronegative atom. And, in fact, if we talk about an ionized acid, normally in the absence of ionization there would be a net zero charge right here. But at neutral pH it may well be the case that the association, for various reasons, between this oxygen and this hydrogen will allow the hydrogen, or rather the proton, the nucleus of the hydrogen atom to just wander away. And, therefore, we can imagine there could be a net negative charge here.
A whole, this has one full electron, electronegative charge here, the charge of one electron, and this proton will have ionized, will have left the carboxylic group in which it originated, and now we have an ionized acid group. Either before or even after this ionization, there is a strong affinity of the carboxyl group with the water around it because let's look at what happened before the ionization occurred.
This carbon here is strong and electronegative. And, therefore, it will participate in hydrogen bonding to the water solvent here, i.e., this proton will be shared a bit between the oxygen of the water molecule and the oxygen right here. Similarly, here this oxygen will be slightly electronegative for the reasons I've just described. And here, once again, there may be some weak hydrogen bonding going on.
Although, not as effective as over here where we have a double-bond where we have a lot of concentration of a cloud of electrons pulled towards the oxygen atom. And this begins to give us clues as to why certain molecules are soluble in water and others are insoluble. For example, if we look at aliphatic compounds. Let's look at a compound that's structured like this.
I guess most people would call this pentane. And we can call it that, too. And this has no electronegativity or positivity by virtue of the equal affinities of these two kinds of atoms, that is the hydrogen and the carbons for electrons. And as a consequence, this will not be able to form any hydrogen bonds with a solvent around it if the solvent happens to be water.
So there's not good bonding here. And this will, in fact, also if one puts this in a solution of water, this will cause all the water molecules to line up in a certain way, almost a quasi-crystal around the aliphatic molecule. They'll be ordered in a certain layer around the aliphatic molecule without being able to form any strong hydrogen bonds with them.
And this ordering represents a loss of chaos, a loss of entropy. Entropy is chaos. It's disorder. It's what happens, let's say, at 10:55 when we all leave the room, all of a sudden order becomes chaotic. And here, before this lining up occurred, the water molecules were chaotically arrayed throughout the solvent. After this lining up occurred there was a loss of entropy, there was a loss of chaos.
And thermodynamics tells us that generally the ordering of molecules is disfavored. And consequently we now have two reasons why this molecule doesn't like to be in the midst of water. First of all, it's unable to form hydrogen bonds with the solvent. And second of all there is a decrease in the entropy, in the chaos that occurs when this molecule directly confronts water. And because of those two reasons it turns out that this molecule doesn't like to be in water.
The aliphatic molecule, as one would call this in organic chemistry, doesn't like to be in water. And a dislike of water is often called its hydrophobicity, or we often call it hydro, might as well spell it right, hydrophobic, i.e., it really hates to be in water. In fact, class, there's a second meaning for hydrophobia, or hydrophobic has a second meaning.
Every five years I ask a class to see who knows what the second meaning of hydrophobia is. This is really obscure. Sorry? Rabies, right. The TAs aren't allowed to answer that. If somebody has rabies, at one stage of rabies, almost near the terminal stage, the individual becomes hydrophobic because he or she doesn't like to drink water, for reasons that are obscure at least to me.
Now, conversely, molecules that have carboxyl group on it would be called hydrophilic. And, as we'll see over this lecture and the next one, these hydrophobic and hydrophilic tendencies tend to have great affects on the overall behavior of molecules. Let's, for example, imagine a situation where we have a long aliphatic tail like this. In fact, these tails can go on in certain aliphatic compounds.
They can go on for 20 or even 30 carbons. And at the end of this, let's just put arbitrarily a carboxyl group. And let's say we ionized it. So here's an acidic group that's ionized. It's shed its proton. It's actually acquired a negative charge. And now we have something, this molecule is a bit schizoid. Because on one end of it, it loves to be in water, the other end of it hates to be in water.
And this has strong affects. It's sometimes called amphipathic, but we don't need to worry about that word. And, therefore, this carboxyl head loves to stick its head, to immerse its head in water. And these things, the aliphatic portion hates to be in water. Now, as a consequence of these rather conflicted feelings that these molecules have about water, we can ask the question what happens when we put such molecules actually into water?
And what we see here is the following. That if we were to construct, for example, a molecule of the sort that has here, in this case we're talking about a molecule that has two hydrophobic tails. We'll get into its detailed structure shortly, but just imagine for a moment two long hydrophobic tails out here ended with a hydrophilic head.
And under such situations, if we put thousands of these or millions of these molecules into a solution of water, what we will then see is, no pointer? All right. Pointer? All right. What we will then see is that the hydrophilic head groups, which are here depicted in red, will point their way outwards, they will want to stick their heads in water.
And conversely the hydrophobic tails fleeing from the water will actually associate one with the other. And so you have a structure that's called, in this case, an a micelle where you form this little globular sphere where the lipid tails are tucked inside. And, therefore, are actually being shielded from any direct exposure to water. This structure down here, the lipid bilayer, is actually, as we will discuss in greater detail shortly, the overall topology of the way most biological membranes are organized.
In fact, virtually all of them. Why is that? Because biological membranes separate two hydrophilic or two aqueous spaces. Thank you, sir. A gentleman you are. So here is an aqueous space and here is an aqueous space. And as we see the hydrophilic heads are immersed or sticking their heads into the hydrophilic space.
This is called a lipid bilayer. And, obviously, it's highly effective for separately these two aqueous compartments. In eukaryotic cells, as I mentioned last time, there is an enormous premium placed on separating and segregating different aqueous compartments which is invariably achieved through the device of constructing these lipid bilayers. Here's a vesicle. A vesicle is more complicated than a micelle.
Because if you look at the membrane lining the vesicle, you see it's actually a lipid bilayer, but one that in 3-dimensional space is actually a sphere. And in the case of this vesicle, we can well imagine that on the inside of the vesicle water is kept, can be stored, and on the outside of the vesicle water can be stored. And many of the membranes that we see within the cytoplasms themselves are actually constructed on this kind of design.
So when we draw, for example, in this case the Golgi apparatus, which I mentioned to you in passing last time we met, each one of these membranes here, it's obviously drawn as a double line, but whenever you see a membrane indicated, implicit in that drawing is the fact that each one of these membranes is actually a bilayer. There are never any monolayers of lipids in living cells. Each one of these vesicles you see here is actually a lipid bilayer with an aqueous inside and, once again, aqueous on the outside.
Again, much of the thermodynamic stability that allows these vesicles to remain intact rather than just diffuse apart is created by these hydrophilic and hydrophobic forces which tie such molecules together or will rip them apart. Now, in truth there are yet other kinds of forces that govern the affinity of molecules to one another. For example, let's imagine a situation where we have an ionized acid group of the sort we just talked about before.
Now, by the way, here, let's say I'll draw the negative charge on one of these two oxygens, if you can see that. But the truth is that the electrons are swarming back and forth, and so the negative charge is shared equally, the negative one electron charge is shared equally between these two oxygen atoms. And this is obviously an area of great electronegativity.
Independent of that, let's imagine up here we have a basic group, let's say an amine group over here. And, the fact of the matter is, amine groups, NH2 groups, that's what an amine is, here's an amine group. This is a carboxylic group. And the amine group, which is used very often in biochemistry, actually has an affinity. It has an unpaired set of electrons on the nitrogen, and so it likes to attract protons to it, which makes it, causes it to be called basic.
And this attraction, the scavenging of protons, perhaps from the water, will obviously give this whole group here a net positive charge, a charge equal to the charge of one proton. Here, once again, we can imagine this is hydrophilic because this charge group can once again also associate quite intimately with aqueous solvent.
Now, independent of any other forces that might exist here, indeed one could imagine situations where there is a sharing of a proton. And, therefore, a hydrogen bond formed between these two. Independent of that is the simple electrostatic interaction of these two groups. That is the mutual attraction of positive and negative groups, one to the other. And the electrostatic interactions, you cannot quantify exactly how many kilocalories a mole there is because the energetic value in electrostatic interaction is equal to one over r squared where r is the distance between these two charged groups.
And obviously the further apart you get the weaker the attraction with one another. There are also what are called van der Walls interactions. There are largely of interest to a very small community of biochemists. You probably will never, you may never hear this term again in your life.
And van der Waals interactions come from the fact that if we were to have, for example, two molecules over here which are not normally charged in any way, let's just talk about two aliphatic chains again. And I won't put in all the protons and everything, but just imagine a situation like this. What will happen is that because of the fluctuations of electrons, because the electrons are swimming around here all the time, moving from one area to the next they're never equally distributed homogenously over a long period of time, there will be brief instance in time, microseconds or even nanoseconds when there happens to be more electrons over here than right here.
Just by chance. And this area of unequal distribution of electrons will in turn induce the opposite kind of electron shift in a neighboring molecule down here. Obviously, depending on the distance between them.
But the negative here will repel electrons down here. The positive here will attract electrons down here. And so you will have these two quasi-polar arrangements here and here, very ephemeral, that is lasting for a very short transient period of time. But, nonetheless, sufficient to give a very weak interaction between these two molecules which may persist only for a microsecond and then be dissipated because the charges then redistributed once again.
And, as a consequence of that, one has very weak interactions which, in the great scheme of things, play only a very minor role in the overall energy which holds molecules together. Now, with that background in mind, let's begin to elaborate on it, on how we can make molecules that have interesting properties that enable them, among other things, to participate in the construction of lipid bilayers, which will be the first object of our attentions today in terms of actual biochemistry.
So here's a fatty acid. We see that up here. I, in effect, drew you the structure of a fatty acid up here already once before. And what we can see is through a linkage known as esterification we can create this molecule. So what do I mean by esterification?
Well, in this case we're talking about a situation here where we have a carbon atom over here like this with a hydroxyl group. You see it over here. And what we're doing is we're dehydrating this, we're pulling out one net molecule of water. And each time we do that, on three separate occasions, what we end up doing is to create instead of this is to create a covalent bond between these two.
And so the end product of dehydrating this, pulling out one net molecule of water is that we end up with a structure that looks like this.
And you see that happening on at least three different occasions, here, here and here. Well, actually, I should put a carbon over here.
So here we have three esterifications. The hydroxyl group in each case is reacting with a carboxyl group here pulling out one water, and each case creating what's called triacylglyercol or triglyceride. Triglyceride refers to the fact that we started here with a glycerol and we have now esterified it. Now, in fact, there are two directions here in this kind of reaction.
Esterification is the kind of linkage that we just showed here. And the truth is that vast numbers of biochemical linkages are made by esterification reactions and reversed by reactions that are called simply hydrolysis. And, in this case, what we're referring to is the fact that if one were to reintroduce a water molecule into each of these three linkages, one, two and three, we would break the bond and cause this entire structure to revert to the two precursors that existed or preexisted prior to these three esterification reactions.
And time and again you'll see, over the next weeks, that esterification reactions are important for constructing different kinds of molecules. Now, the fact of the matter is we can do other kinds of modifications of a glycerol like this.
Here what we've done, instead of adding a third fatty acid, note what was done here. Here through an esterification, let's look up at this one here, instead of adding a third fatty acid, we've saved, we've reserved one of the three groups of the glycerol. Here's what we saw just before. We've saved one of the three groups of the glycerol and put on instead this highly hydrophilic phosphate group, once again through a dehydration reaction, an esterification reaction.
And now what we've done is add insult to injury because in the absence of this phosphate it would have a hydroxyl here which is mildly hydrophilic. But now look how strongly charged this is. Here are two negative charges, one electron each. And this is already a bit electronegative. So here we have an extremely potent hydrophilic entity. And here the degree of schizophrenia between one end of the molecule and the other is greatly exaggerated. Here, in fact, this is extremely hydrophilic.
And, as a consequence of that, this really likes to stick its head inside water. And when we therefore talk about, we draw the images of different kinds of membranes, like this I showed you before the two tails. Here you saw the two tails I drew before in that diagram. Here's what we can imagine they actually look like in more real molecular terms. And the hydrophilic heads sticking in the water, this is just repeating what we saw before, become even more hydrophilic if we look at a molecule like this.
Let's look at this thing here. Here's a very long hydrophobic tail. Here are the two glycerols once again. Here is the phosphate. And keep in mind that phosphate obviously has these extra oxygens. Phosphate can react with more than just one partner, the glycerol down here. In this case we've added this group up here. And this group up here is, once again, this happens to be a serine which is an amino acid, this also happens to be quite hydrophilic.
Here's our old friend the basic amino group. Here's the carboxyl group. This is a bit hydrophobic, CH2. And then we once again have the hydrophilic head here. And, therefore, we imagine, if we look at what's called a space-filling model, and a space-filling model really is intended to show us what one imagines if one had this vision, which we don't have, how much space each of these atoms would actually take up if one were able to see them.
And here we see this space filling model. This lipid molecule here is actually slightly kinked with its hydrophilic head tucked into the water space. And so here's actually the way that many biological membranes look in terms of the way that they are constructed. Now, the fact of the matter is this also affords the cell the ability to segregate contents on one or the other side of whatever lipid bilayer it happens to have constructed.
And here we can see about the semi-permeability, how permeable these membranes are to different kinds of molecules. Permeability obviously refers to the ability of this membrane to obstruct or to allow the migration of molecules from one side to the other.
Ions, and these ions we see right here are obviously highly hydrophilic by virtue of their charge. That's explains, in fact, why, for example, table salt goes so readily into solution, because it readily ionizes into sodium, NA and CL, which then are avidly taken up by the water molecules. So these are highly hydrophilic ions. And the questions is, can they go from one side of the membrane to the other? And the answer is absolutely not or highly improbably. Why?
Because these are so highly hydrophilic, the water molecules love to gather around them and form hydrogen bonds and electrostatic bonds with them. And if one of these ions ventures over here, it's going from an area where it's warmly embraced by the solvent molecules to an area where these molecules intensely dislike these ions. And, therefore, thermodynamically the entrance of any one of these ions into the membrane, into the hydrophobic portion of the membrane is highly disfavored, which makes the membrane essentially, for all practical purposes, impermeable.
The same can be said of glucose which happens to be a carbohydrate. We'll talk about it shortly. But it's also nicely hydrophilic. It also can go in water. In fact, it can go through. And it's actually the case, to my knowledge, that one doesn't really understand to this day why lipid bilayers are reasonably permeable to water. You would say, well, water shouldn't be able to go through.
It clearly doesn't have to have a net positive or negative charge, but the physical chemist, if you asked them why does water, why is water able to go through lipid bilayers? They'll say, well, we've been working on that and we'll get you an answer in the next five or ten years. And they said that 40 years ago and 30 years ago, and they're still saying it. And we don't really understand why water goes through, which is an embarrassment because here's one of the fundamental biochemical properties of living matter that is poorly understood. Gases can go right through.
And amino acids, ATP, glucose 6 phosphate, highly hydrophilic, can also not go through. Now, the advantage of this is that a cell can accumulate large concentrations of these molecules either on the inside or it can pump them to the outside. In other words, it can create great gradients in the concentrations of different kinds of ions. For example, in many cells, the concentration of calcium, CA++ is a thousand times higher on the outside of the cell than on the inside of the cell which is a testimonial to how impermeable these lipid bilayer membranes are.
The fact of the matter is I'm fudging a little bit here because in the lipid bilayers of the plasma membrane of the cell, the outer membrane of the cell that we talked about in passing last time, there are ion pumps which are constantly working away pumping ions from one side to the other overcomes the little bit of leakage which may have occurred if a calcium ion happens to have snuck through in one direction or the other.
And we end up expending a lot of energy to keep these ion gradients in appropriate concentrations on the outside and the inside. In fact, virtually all the energy that is expended in our brain, almost all of it is expended to power the ion pumps which are constantly insuring that the concentrations of certain ions on the outside and the inside of neurons are kept at their proper respective levels.
It could therefore be that actually more than half of our metabolic burden every day is expended just keeping the ions segregated on the outside and inside of cells. For example, potassium is at high levels inside cells, sodium is at high levels outside cells, just to site some arbitrary examples. There are also, by the way, as I mentioned last time, channels.
And channels are actually just little doughnut shaped objects which are placed, inserted into lipid bilayers in the plasma membranes and just allow for the passive diffusion of an ion through them, through the doughnut hole enabling an ion, so if here's the lipid bilayer, not showing its two things, these kinds of doughnut shaped protein aggregates will allow the passage of ions in one direction or another.
And here energy is not being expended to enable this passage. It may just be through diffusion. If there's a higher concentration of ion on side of the lipid bilayer and a lower one on this side, this diffusion will allow the ion to migrate through the bore of the ion channel from one side to the other. In fact, even though this does not involve the expenditure of energy on the part of the cell, the cell may actually use a gating mechanism to open or close these channels.
When the channels are closed then the ions cannot move through. When the channels are gated open then diffusion can take over and insure the transfer, the transportation of ions from one side to the other. Now, having said that, we can begin to look at yet other higher level structures. Here, by the way, is a better drawing than the one I provided you. This comes from your book of what a vesicle looks like.
Here's what it looks like under the electron microscope and here's what it looks like when a talented rather than hapless and hopeless artist like myself tries to draw it. So let's just say that's our intro into lipids and membranes. And let's move onto the next layer of complexity. And the next layer of complexity in terms of molecules represents carbohydrates.
And when we talk about a carbohydrate amongst ourselves we're talking about a molecule which, roughly speaking, has one carbon atom for every water molecule. And we'll shortly indulge ourselves in talking about all kinds of different carbohydrate molecules. Here is really one of the most important carbohydrate molecules, glucose. And what should we note about glucose? Well, the first thing you should see is that glucose has six carbon atoms. And, therefore, as a consequence it's called a hexose.
We're going to talk about pentoses very shortly. They only have five, to state the obvious. Glycerol, which we talked about before, is also considered in one sense a carbohydrate, but it's been called by some people a triose. It only has three carbon atoms. And you can imagine, therefore, in principal that there are certain biochemical mechanisms which indeed exist which enable one to join two glycerol molecules, one to the other, to create something like a hexose, glucose.
In fact, what we see from this drawing, expertly drawn by yours truly, is that the hexose molecule isn't really a linear molecule in solution. What happens is that because of various steric and thermodynamic forces it likes to cyclize. So let me just mention, I've just used two words that are useful to know about.
Steric or stereochemistry refers to the 3-dimensional structure of a molecule. And, obviously, the stereochemistry of a molecule is dictated by the flexibility with which participating atoms can form bonds, whether we have a trivalent atom like nitrogen or a tetravalent atom like carbon or a monovalent like hydrogen.
And these structures, the stereochemistry is dictated both by what atoms are present here and by thermodynamic considerations which cause this particular hexose, indeed virtually all hexoses, to cyclize. When I say cyclize, obviously I mean to form a circular structure. Here we note one thing. You can see how the hydroxyl here actually attacks the positively charged carbon here in order to form this cyclic structure.
You see one of the six points on this hexagonal structure here is oxygen. It's not carbon at all. So there is one oxygen and five carbons. And one of the carbons is relegated, is exiled to outside of the circle. It's sometimes called an extracyclic because it's sticking out from the actual circle.
And this is the structure in which glucose actually exists inside cells. And, in fact, there is, in truth, two alternative ways by which glucose can cyclize, whether the oxygen attacks the carbon on the carbonyl group underneath or on top. And you see that gives us two alternative structures. What's different about them? Well, if we think about this hexose as existing in a plane, or the hexagon is in a plane
In this case the oxygen is above the plane and the hydrogen is below the plane. With equal probability you can have these two atoms reversed where hydrogen is now above the plane and hydroxyl is below the plane. And both of these structures, these alternative structures can fairly be considered to be glucose. Now, let's get a little bit more complicated. Here we have fructose and we have galactose.
And what we see here is, by the way, that we have exactly the same number of carbon atoms and hydrogen atoms and oxygen atoms but they're hooked up slightly differently. And here now we begin to get very picky about the disposition, the orientation of these different kinds of hydroxyls and hydrogens. And note, by the way, here that in many cases one doesn't even put in the H for the hydrogen. It's just implied by the end of this line.
And here, if you were to look at this, you'll see here now we have two extra cyclic carbons. Here's galactose which is yet another hexose. These are all hexoses, but their stereochemistry creates quite different kinds of structures. And it turns out that this stereochemistry is extremely important. These molecules function very differently, one from the other.
And, for example, to the extent that glucose is used in different kinds of energy metabolism and to the extent that galactose is not, there must be certain biochemical mechanisms in which one has catalysts, the catalysts that we call enzymes that ensure that one can convert one of these hexoses through an enzyme into, let's say a less useful one into a more useful one, glucose, which can readily be burnt up by the energy-generating machinery. Here we've gone yet another order of magnitude more complex because we've gone from a monosaccharide, i.e., one or another hexose, to a disaccharide.
And here's common table sugar. And here you see that it's formed once again through an esterification reaction, i.e., there is a dehydration reaction between this hydroxyl here and this hydroxyl here. And biochemists take the orientation of these hydroxyl and hydrogen groups very seriously. Now, you can say they're a bit obsessive. Indeed they probably are.
But, nonetheless, we can admit that the specific orientations of all these things dictate very importantly the difference between here, in this case sucrose, and in this case lactose. Why is this important? Well, this is the sugar in milk sugar. This is the dominant sugar in milk sugar, lactose. And half the world, as adults, cannot absorb this. All kinds of unpleasant things happen when they actually drink milk.
How many people here are lactose intolerant? It's nothing to be ashamed of. I'm married to a very lactose intolerant person. She's otherwise very nice. The fact is that the enzyme to break down lactose, it's an enzyme which is called lactase. And here we have yet another nomenclature item. So lactase is the enzyme which breaks down lactose.
And, by the way, this is just the harbinger of many other enzymes we're going to talk about in the future that end in A-S-E. Whereas, carbohydrates, many of them end in O-S-E, as you've already sensed. So it turns out that the enzyme lactase is made in large amounts by most mammals very early in life. Why? To be able to breakdown the milk sugar that comes in their mother's milk.
But once mammals are weaned there's no reason on earth for them to continue to make lactase, in their stomach for example. And, as a consequence, in most mammals the production of lactase is shut down later in life. And for some weird quirk of human history, a significant proportion of humanity has learned how to retain the ability to make lactose through adulthood. And, as a consequence, people can go and have ice cream until the age of 70, 80 or 90 without becoming very bloated.
And we don't need to get into all the details, but you can begin to imagine. And what happens is, therefore, the lactase enzyme is shut down in their stomach. It depends. Sometimes they lose it at the age of 10 or 15 or 20. And then, for the rest of their lives, whenever they have a milk containing product, in fact, my son is also lactose intolerant. I'm surrounded by these people. Again, he is otherwise a tolerant person but he's lactose intolerant.
So this lactose molecule will go into the stomach, it will remain undigested, it will remain a disaccharide instead of being cleaved into two monosaccharides. The two monosaccharides are no problem because they can readily be interconverted. The galactose can be readily converted into glucose, and glucose is the universal currency of carbohydrate energy. And so this disaccharide passes through the stomach unaltered and it gets into the intestines, in the small intestine and the large intestine.
And it turns out we have more bacterial cells in our gut than we have our own cells in the rest of the body. Imagine that. And there are a lot of bacteria that are waiting around in the gut for just a little gulp of lactose. And they never get it because most people break down their lactose long before it gets into the intestine. But here we have these lactose intolerant people.
The disaccharide gets into the gut and the bacteria go to town. They've been waiting around for years, decades for a little bit of lactose. And now it finally arrives and they go to town, ad they start metabolizing it and they ferment and they produce lots of gas and other kinds of byproducts. And, as a consequence, this makes people very uncomfortable. Just to show you, now, the fact is that lactose intolerance people can perfectly well break down sucrose, obviously. This is one of the great energy sources from plants.
But they cannot break this down. And I emphasize that point to indicate that the stereochemical differences between different kinds of carbohydrates makes a very important difference. An enzyme like sucrase will break down the sucrose but it will not touch lactose. So there's a high degree of stereospecificity as it's called in the trade. Here we now go to another step forward that we're going to pursue in much greater detail next time.
Because here, for the first time, we talk about polymerization. We're making polymers. Where the large number of hydroxyl groups on these monosaccharides affords one many opportunities to make very long linear aggregates end-to-end like this or even side branches. If you imagine that each one of these hydroxyls, in principle, represents a site for possible esterification, i.e., the formation of a bond to a neighboring side chain.
Here we see these two linear chains and here we see the branch which is afforded, which is made possible by the availability of these unutilized hydroxyl side chains which are just waiting around to participate, if the opportunity allows them, in some kind of esterification reaction to form a covalent bond. Here is, by the way, glycogen, which is the way we store a lot of sugar in our liver.
Here's a starch, which is what we get from many plants. And here's another very interesting polysaccharide. It's called cellulose. And we cannot digest cellulose, but termites can. And why they can is something we'll have to wait until next time to learn about. Have a great weekend. See you on Monday.


We made sugar cube sculptures. What a fun and surprising lesson in building, painting, and dissolving!
- Box of sugar cubes
- Glue bottle
- Sturdy base to glue onto
- Paint in squeezy bottles
Boxes of sugar cubers were harder to find than I thought, but I ultimately found them at our big supermarket (and bought 2!). We used scrap wood for the base, basic Elmer’s school glue, and Nancy Bottles for the paint.
I suggested that we could build a sculpture with the sugar cubes, and presented N with the materials. That’s all she needed to hear before she began to glue the cubes onto the panel.
And stack them up tall.
You can see that this isn’t the strongest structure in the world!! I filled some Nancy Bottles with watered down BioColor paint, which my daughter then squeezed all over the sculpture. Because the water acted as a dissolving agent, if I were to do this again I’d use straight-up paint without the additional water.
It’s looking a little patriotic, no?
And it end up in this beautiful heap of swirly, melting color. Not exactly what I imagined when we started, but it did lead to some wonderful conversations about dissolving. We only used about 1/10 of the sugar cubes to make the sculpture, so why not set up a dissolving experiment with the rest of the cubes?!
The next day N turned the remaining cubes into sugar water in under five minutes. It was quick, but what a great lesson and experience!


5,6) Our results substantiate this claim for Staphylococcus and Corynebacterium
species because these were the most common bacterial colonies isolated.
The ethanol extract also exhibited high activity against the growth of Corynebacterium
glutamicum, Staphylococcus epider areus and Staphylococcus epider midis in comparison with other organisms.
This high success rate showcased the market potential for the Corynebacterium
glutamicum expression method - especially with proteins that traditional expression systems had struggled to express.
The patients also had large increases in the amount of Corynebacterium
tuberculostearicum in their sinuses, which are located in the forehead, cheeks and eyes.
2002, optimization of culture conditions for L-lysine Fermentation by Corynebacterium
glutamicum, On Line J.
aureus, coagulase-negative staphylococci (CNS), and Corynebacterium
Genetic analysis of tox+ and tox-bacteriophages of Corynebacterium
The disease is caused by the bacteria Corynebacterium
pseudotuberculosis, and is a chronic condition characterised by the formation of abscesses in the glands, which eventually burst and discharge greenish yellow pus.
Las bacterias localizadas fueron staphylococus epidermis, staphylococus species y corynebacterium
In a paper published online in Environmental Health Perspectives, Sapkota's team lists many of the most prevalent bacteria present, including Campylobacter, which can cause food poisoning; Clostridium, Corynebacterium
, Klebsiella, Pseudomonas aeruginosa and Stenotrophomonas maltophilia--all of which are associated with pneumonia and other infections; E.
striatum deri florasinda yer alan Corynebacterium
tiplerinden birkacidir (2).
The most common infective cause of laryngeal webs worldwide is Corynebacterium
Nevertheless only a few gram positive genera like Corynebacterium
, Streptomyces and Rhodococcus are able to mineralize a wide array of aromatic compounds [15,16,17,18,191.
The organisms were chosen after a preliminary screening test for resistance to the salts of these heavy metals employing bacterial isolates (Alcaligenes, Aeromonas, Bacillus, Achromobacter, Chromobacterium, Corynebacterium
, Micrococcus , Pseudomonas and Serratia) isolated from the New Calabar River water.
matruchotii is found higher in the case of aggressive periodontitis.


Here's a few additional resources on the Spanish Civil War in case you wanted to put our August book, Watcher in the Pine, in context. Google Cultural Institute has an easily digestible multimedia spread that gives you the basics. For a little additional period color, you can watch The Spanish Earth, a 1937 pro-Republican propaganda film narrated by Ernest Hemingway. If you'd like a little more depth, try this podcast from the BBC In Our Time Series.
As with many divisive periods in a nation's life (I'm thinking of our recent reading of Anna Funder's Stasiland about East and West Germany) the process of reconciliation is ongoing. Just this year, Amnesty International released a report, "Time Passes, Impunity Remains", criticizing the Spanish government for blocking investigations into Franco-era crimes,
“The fact that Spain is neither investigating nor cooperating with proceedings relating to crimes committed during the Civil War by both parties to the conflict or under Franco is a slap in the face of all the relatives of those who were abused and disappeared at the time,” said Esteban Beltrán, Director of Amnesty International Spain.
“We have seen a tendency for these cases to be closed without further investigation but the situation has worsened recently after the Supreme Court ruled that it was not for Spanish judges to prosecute these crimes. The only avenue of judicial investigation available in Spain it seems to be shut down.”Amnesty is urging authorities in Spain to investigate and prosecute crimes or offences under international law and to assist fully with any request for cooperation it receives from foreign courts that decide to investigate these crimes. For more on how Spaniards are confronting the legacy of the Franco era, watch "Franco's Ghost" above.


French Guiana (pronounced /ɡiːˈɑːnə/ or /ɡiːˈænə/, French: Guyane française; French pronunciation: [ɡɥijan fʁɑ̃sɛz]), officially called Guiana (French: Guyane), is an overseas department and region of France, located on the north Atlantic coast of South America in the Guyanas. It borders Brazil to the east and south, and Suriname to the west. Its 83,534 km2 (32,253 sq mi) area has a very low population density of only 3 inhabitants per km2, with half of its 244,118 inhabitants in 2013 living in the metropolitan area of Cayenne, its capital. By land area, it is the second largest region of France and the largest outermost region within the European Union.
The area was originally inhabited by Native Americans. It was colonised by Frenchmen and other Europeans, who introduced African slaves and later Asian labourers and Hmong refugees from Laos.
The official language is French, while each ethnic community has its own language, of which Guianan Creole is the most widely spoken.
Part of France since the 17th century and fully integrated in the French central state since 1946, Guiana joined the European Union, and its official currency is the euro. The region is the most prosperous territory in South America with the highest GDP per capita. A large part of Guiana’s economy derives from the presence of the Guiana Space Centre, now the European Space Agency’s primary launch site near the equator.


Oral Care Glossary
Dentists and Hygienist have a language all their own. This guide breaks down the professional terminology into everyday language.
When the inside of the mouth gets hurt or irritated, bacteria may enter and cause an infection. Sometimes you will see a painful swelling filled with pus (a thick, yellowish fluid). If the pus can't drain out, the area will get more swollen and painful. This is known as an abscess. The abscess forms a barrier around the infection. This is one way that the body tries to keep a bacterial infection from spreading.


Food and Agriculture Organization of the United Nations (FAO) and the Ministry of Environment signed an agreement to implement two projects one aimed to identify bioenergy options suitable to the Rwandan context and another water governance, water accounting and water use efficiency.
During the signing ceremony, the Minister of Environment, Vincent Biruta thanked the FAO for the support saying that it will complement the government’s efforts to impact use of bioenergy and on land restoration and environment.
“The Ministry of Environment is mainly concerned with energy from bioenergy required for cooking. However, biomass remains a serious issue needing appropriate intervention. We cannot increase the forest cover without addressing the issue of cutting down trees for fuel wood but also polluting the environment,” said Biruta.
Rwanda is heavily dependent on biomass energy. In fact, between 1990 and 2010 the country has lost 37 percent of its forest cover. According to Integrated Household Living Conditions Survey 5 (EICV 5), about 84% of households in Rwanda use firewood as their primary cooking fuel, and for lighting. On average, households consume around 1.8 tons of firewood per year to satisfy their cooking needs.
The FAO Representative in Rwanda, Gualbert Gbehounou said that besides the bioenergy project, there is need to address issues related to natural water resource management so to strengthen the country’s water governance for greater food security.
“Climate resilience is an important factor in effective water management. The projects will therefore look at how to maximize every drop of water there is, analyze and identify potential bioenergy feedstock and technologies that can be developed in Rwanda for both decentralized energy production and for cooking purposes,” said Gualbert.
During the implementation of the projects, FAO will work with national stakeholders including, the Ministry of Agriculture and Animal Resources, Ministry of Infrastructure, development partners and private actors.
About the projects
The first project “Bioenergy and Food Security Assessment and Capacity Building for Rwanda” will support the Ministry of Environment to identify which bioenergy options can be environmentally sustainable and contribute to the targets set within the Nationally Determined Contributions (NDCs). NDCs embody efforts by a country to reduce national emissions and adapt to the impacts of climate change. In addition, the project will also provide capacity building trainings on the use of the bioenergy tools to key stakeholders involved in the bioenergy sector and in the development of the Biomass Energy Strategy.
The second project “Knowing water better: Towards fairer and more sustainable access to natural resources for greater food security (KnoWat)” aims to strengthen water governance, water accounting and water use efficiency, for greater food security so that Rwanda is better prepared to adapt agriculture to climate change, water scarcity and increased competition for water resources in an equitable and sustainable manner. The project will support three countries, Rwanda, Senegal and Sri Lanka.
What is sustainable bioenergy?
Sustainable energy refers to energy that is accessible, cleaner and more efficient to achieving economic development and poverty reduction targets.
Bioenergy is energy from biofuels. Biofuel is fuel produced directly or indirectly from biomass. Biomass is material of biological origin, for example wood, dung or charcoal and it excludes material embedded in geological formations and transformed to fossils.
Bioenergy and food security interlinkages
Bioenergy can be generated from all agricultural products and can be used for heating, cooking and lighting.
For instance, a household can use manure of the livestock to produce green fuel for cooking and lighting. The manure can be used to get fertilizer for crops thus increasing food for consumption and for the market to earn income.
Bioenergy if managed sustainably and efficiently can bring in resources and boost productivity while improving food security. Bioenergy sector can create a new market for producers as well as offer new forms of employment that will positively affect agricultural and rural incomes, poverty reduction and economic growth.
Also, bioenergy has the potential to contribute to environmental objectives including the reduction of greenhouse gas emissions.


We explain what art is, the history of its origin and the types that exist. Also, what are its general characteristics and importance.
What is the art?
Art or arts is called a set of human activities of a creative, communicative and subjective nature , which pursue an aesthetic purpose, that is: they try to move, produce beauty, awaken feelings or reflections, all through the manipulation of materials of diverse nature.
One of the most important features of art is its ability to last over time , allowing later generations (or even later cultures ) to know something about the history , beliefs, language and/or sensibilities of the society and time. in which it was created. In this way, art is also a historical element.
Those who engage in the creation of art are known as artists . There are also those who specialize in the interpretation, classification and study of art , called art critics .
The concept of art comes from what was called in the eighteenth century the “Fine Arts”.
There is no single and definitive concept of art, since the question about what art is is part of the explorations that art itself poses. In any case, art is an important part of human culture. It is a concept that changes over time , allowing the inclusion of new forms, content and techniques to what is known at the time.
Currently, the concept of art comes from a generalization of what was called “Fine Arts” in the eighteenth century , to distinguish them from crafts and popular manifestations. This concept, already in disuse, included literature, sculpture, painting, music, dance and architecture. In the 20th century , cinema, photography and comics were incorporated.
Origin of Art
The first artistic manifestations of the human being date from prehistory , when the first tribes of Homo sapiens (and perhaps of Homo neanderthaliensis ) decorated the interior of the caves in which they lived with mixtures of pigments and animal fat.
Those first forms of cave art were drawings of totem animals, hunting scenes or impressions of their own hands , who knows if for narrative, shamanic or ritual purposes. Many of those paintings are preserved to this day.
However, the concept of art itself did not always exist , but rather emerged in classical antiquity , especially in the great cultures, such as the Chinese or the Greco -Roman . The latter was also the first to produce theoretical or critical texts regarding art, such as Aristotle’s Poetics , for example, founder of literary criticism.
Plutarch’s studies also come from the Greco-Roman culture , who distinguished for the first time between “useful arts” (such as current sciences ) and “pleasant arts” (such as current arts).
History of Art
In the 19th century, art began to be taken as the peak of human expression.
In ancient times, especially Greco-Roman, the arts were associated with divine influence . The ancient Greeks had specific muses for each form of art, to whom they attributed the necessary inspiration for their exercise.
During the Middle Ages , in the West , the arts began their separation from what was called artificium , that is, “mechanical” or “vulgar” arts , distinguishing between what was later called crafts ( ceramics , goldsmithing, etc.) and what which was called “liberal” arts, which were supposedly the arts of the spirit. During this period the arts were at the service of Christianity .
This concept was accentuated after the sixteenth century , after the artistic and philosophical outbreak of the European Renaissance . Since then, it began to be considered that the artistic profession (especially painting, architecture and sculpture) required something more than simply craft and skill: it required a certain artistic genius. These were then called “design” arts.
Thus , in the 18th century, the concept of “Fine Arts” arose . The great diversification and liberalization of the arts in the 19th and 20th centuries resulted in the consideration of art as the pinnacle of humanity’s expressive genius, a more or less refined way of recording our passage through the world.
Types of Art
The performing arts have an audience that watches the show.
There are many ways to classify art, such as periods, cultures of origin or, the main one, according to the nature of its representation. Thus, we can talk about:
- Decorative arts. Combination of art and craftsmanship, aimed at producing beautiful as well as functional objects, thus combining the industrial and artisanal worlds. They are also known as applied arts or industrial arts.
- Plastic arts. Those that use materials that the artist can modify, alter or combine to produce a work. This term is deprecated in favor of the broader “visual arts.” Traditionally, “plastic” refers to painting, drawing, sculpture, engraving and other forms of ceramics and goldsmithing.
- performing arts Those that need to be performed on a formal stage (a theater, for example) or informal (a square), and that have an audience that watches the show. It traditionally refers to dance, theater , music, and film.
- literary arts. Literature is the art form that uses language and writing to produce aesthetic works, whether of a rhythmic and descriptive type ( poetry ), narrative ( novel , short story ) or theatrical texts (dramaturgy).
Literature is artistic expression through the use of the word.
Traditionally, nine artistic disciplines are recognized, also called “Fine Arts”, which are:
- Painting . Visual artistic expression, which uses colors and shapes to produce still works on a two-dimensional canvas.
- Sculpture . The construction of three-dimensional objects endowed with shape, color and volume, and even in some cases penetrability or interactivity, to provide the viewer with an aesthetic experience.
- literature . Artistic expression through the use of the word and its written resources, to produce legible and interpretable textual bodies.
- Music . Through the execution of various types of instruments (string, wind, percussion, etc.), music offers the viewer an experience of harmony, melody and rhythm, in which the human voice may or may not intervene.
- Architecture . It is about the construction of spaces and buildings that can be inhabited and that also provide their inhabitants with a sense of beauty or that transmit a specific aesthetic message.
- Dance . Those artistic expressions that use the human body on stage, accompanying it with music or other rhythmic forms to express an aesthetic content.
- Cinema . An art form that consists of the sequential montage of images and sounds that can then be projected and reproduced on a stage, to give the public a sense of movement and an aesthetic audiovisual experience.
- Photography . Forerunner of cinema, it consists of capturing light on photosensitive surfaces or devices, capturing the image of the surrounding reality and then reproducing it motionlessly.
- Sequential art. The so-called cartoon , comic or vignettes, is a form of narration that combines text and image with elements of graphic design, to produce an aesthetic experience.
There are other forms of art that are not formally recognized yet, such as gastronomy, street art or fashion, so there is a lot of debate about what the tenth art can be.
Art, said Oscar Wilde, is profoundly useless. That is, it does not fulfill explicit functions nor is it applicable to anything . But at the same time it can fulfill involuntary functions: document of an era, personal testimony, decoration or embellishment of a space or a city , or a vehicle for the transmission of cultural , ethical or spiritual values.
Works of art acquire more and more interpretations over the years.
Art is an abstract, intangible concept . But the works in which he expresses himself are not, regardless of their genre and discipline. Some works of art are more concrete, such as a painting, a sculpture or a building, while others are intangible and require a written or audiovisual support, such as a symphony, a novel or a theatrical or dance performance.
In any case, works of art endure over time and acquire more and more possible interpretations as generations know them, version them and spread them.
Importance of Art
Art is one of the most important and lasting manifestations of what is human. Thanks to art we can reflect on our own condition , our sensitivities, or we can communicate our anxieties, shape our fears, in short, carry out a whole spiritual task that is part of who we are as a species.
The restorers preserve and allow the exhibition of ancient works.
Works of art lose some of their perfection over time as the materials age. For this reason, there is a need for restorers: professionals who, imitating the techniques with which the work was originally done, propose to restore or replicate it.
In this way , it is guaranteed that the work can continue to be exhibited and is preserved for later generations. It is usual for each museum to have its own team of restorers.
Examples of Art
Examples of art abound in everyday life. The music that the orchestra plays during a performance, the paintings and sculptures that a museum exhibits, the poems that abound in books or the beautiful architectural spaces that we can visit, are all examples of the artistic capacity of the human being .
The above content published at Collaborative Research Group is for informational and educational purposes only and has been developed by referring to reliable sources and recommendations from experts. We do not have any contact with official entities nor do we intend to replace the information that they emit.


f, as many health professionals believe, our greatest public health challenge lies in stemming the rising human and financial burden of chronic disease, then developing a better way to identify and manage such illnesses is crucial.
Eduardo J. Simoes, professor and chair of MU’s Department of Health Management and Informatics, has spent much of his career working to further this elusive goal, developing “prioritization models” that are helping chronic-disease epidemiologists — those who investigate the causes and ways of controlling non-infectious illnesses — to plan and deploy interventions designed to keep us all healthier.
“This method of prioritizing public health programs, especially in prevention and health promotion, was created back in 1998,” says Simoes, who, while holding joint appointments as an adjunct professor at MU and associate professor at Saint Louis University, also served as chief epidemiologist for the Missouri Department of Health and Senior Services. “At that point, there was a lot of demand on the states to do better in working with local public health agencies.”
This task was anything but simple. Missouri has 115 independent public health agencies, one in each county. The cities of St. Louis, Kansas City and Joplin also have health departments, offices whose responsibilities often overlap with those of counties in their metro areas. Each of these agencies is charged with protecting its citizens from a dizzying array of health concerns and doing it with shrinking financial support from budget-challenged state coffers.
“As the chronic health epidemiologist working with the state on a whole host of chronic health issues, I felt the need to create something that would help them,” Simoes says.
imoes was well equipped to do the job. Born in Brazil, he earned a doctor of medicine degree at the University of Pernambuco in Recife before leaving his homeland to enroll in a graduate program in England. There he completed a master’s degree in community health for developing countries and a diploma in Tropical Medicine & Hygiene (DTM&H) at the prestigious London School of Hygiene and Tropical Medicine. Simoes later moved on to the School of Public Health at Emory University in Atlanta — an institution with close ties to the Centers for Disease Control and Prevention. While there, he added a master’s degree and a doctorate coursework in epidemiology to his long list of credentials.
Simoes began his career at the Missouri Department of Health and Senior Services in the mid 1990s. At the time, Bert Malone worked as the director of the Division of Chronic Disease Prevention and Health Promotion. Malone says Simoes’ research was already prioritizing the risk factors that burden a community with chronic disease.
“It allowed us to sharpen our focus on those areas where there was the greatest burden of disease or anticipated disease based on risk factors associated with those conditions,” Malone says. “And that’s the first time we really had any kind of a model that we could use to prioritize our limited funding. Chronic disease issues are definitely the future of public health.”
The CDC describes chronic disease as “among the most common, costly and preventable of all health problems in the U.S.” Such conditions include heart disease, stroke, cancer, diabetes and arthritis.
“These are all huge problems, and there’s no way that the resources that we have available to address these in a state like Missouri — or even in the nation — can drastically reduce the burden of those diseases unless we prioritize the top risk behaviors associated with those conditions and prevent disease rather than just treat the disease once it develops,” says Simoes.
Epidemiological studies seek to accomplish four key things: to identify the disease or health event; assess its rates of occurrence (who has been diagnosed with the condition, or has acquired the risk factors?); determine its prevalence (what percentage of a given population is suffering from or carrying it?); and, finally, its potential for mortality (among those affected or at risk for being affected, how many are dying or becoming sick?). Gathering these data not only allow epidemiologists to identify and contain outbreaks of infectious diseases — the 2002 outbreak of Severe Acute Respiratory Syndrome (SARS) for example — but also to gather detailed information on health risks related to more persistent and predictable factors in chronic illness: think tobacco use, unprotected sex, obesity, exposure to potentially harmful chemicals, and so on.
During his time working with the Missouri Department of Health and Senior Services, Simoes noticed a problem. When a county was confronted with an infectious outbreak, for instance, pertussis at an elementary school or norovirus at a church supper, both local and state officials moved quickly and efficiently to marshal the resources they needed to combat its spread. But when it came to addressing chronic illnesses and conditions, health officials were less likely to use the available data to maximize their disease-fighting resources.
Clearly, Simoes thought, something needed to be tweaked. The problem, he says, was not that the traditional way of identifying particular chronic disease problem wasn’t working. It just didn’t go far enough.
“It gives you a sense of the priority but doesn’t really give you the full flavor of priorities, because the comparisons make you look for a target that is perhaps not realistic for your county,” says Simoes. His model, on the other hand, uses six specific criteria — and a mountain of available epidemiological data on each one — to help local agencies size up their own situations: these include an evaluation of the size of the problem, its severity, the urgency of intervening and the likelihood that the intervention will have the desired effect, its cost, how much community support officials might expect, and, finally, whether there are disparities among those who suffer from the condition in race or other socioeconomic characteristics.
he model has now been in place in Missouri for close to a decade. It works in practice thanks to a simple digital interface. At a website hosted by the state, users of Priority MICA [Missouri Information for Community Assessment] enter locally relevant, health-prioritization information via an electronic form. When completed, they simply click “compute priorities” and, thanks to a database packed with a wide variety of surveillance system information, a ready-made roster of risk-factor and disease-priority rankings pops up.
Cash-strapped agencies thus not only gain a quantitative insight into their communities’ health needs, they can also initiate action even if statistical and epidemiological support isn’t readily available.
For Bert Malone, now public health administrator at the Kansas City Health Department, the system has been just what the doctor ordered.
“We use that model of risk behaviors to help us target initiatives that need to be implemented in our community,” he says. “For example, tobacco. Instead of looking just at the rates of cancer or cardiovascular disease, we now, using this model and the data that [Simoes] helped us have more readily available, focus on risk behaviors associated with those conditions, like smoking, or sedentary lifestyles or inadequate nutrition. We can focus our efforts on ultimately preventing those diseases and intervening earlier in the onset of those late-stage conditions once they do, in fact, develop.”
Throughout the United States, Simoes adds, similar opportunities exist for local agencies to target their efforts.
Because every state, county and community juggles different trends and needs in public health, Simoes says, local health officials are engaged in a balancing act with the health needs of a particular community and the interventions available. “By reviewing localized data and previous research that examined promotion and preventive interventions, public health officials can create and fund programs that target the most important issues in their communities.”
The model looks at which risk factors are important now and which ones will be an issue in the future. It takes the criteria laid out in the model to determine the severity and can weigh criteria differently depending on the needs of the local community.
“We have all these data for the states and data for the majority of the counties,” Simoes says. He adds that the CDC and state departments of health have made an effort to have risk factor data available to the counties based on the region or the Behavioral Risk Fact Surveillance System — an on-going telephone health survey system that, since 1984, has tracked certain health conditions and risk behaviors in the United States. Also, data on disease morbidity, hospitalization and mortality is available for all cities and counties in the nation.
“So prioritizing public health action based on risk factors or diseases using this model is doable for every one of the 3000-some counties in the United States,” Simoes says.
ollowing the successful implementation of the Priority MICA, Simoes was asked to help the Italian Ministry of Health develop something similar for that country. The result, details of which were published recently in the International Journal of Public Health, reflected the greater complexity of undertaking a prioritization system for an entire nation.
For the Italian project, Simoes and his hosts identified 15 specific risk factors then calculated priorities using a slightly modified set of criteria. These included: severity, the proportion of deaths attributable to the risk factors; magnitude, the prevalence of people engaging in the at-risk behavior; urgency, the increase or decrease in risk factor prevalence; disparity, the differences in risk-factor prevalence among different populations; effectiveness, how well are treatments and interventions working; and, finally, the anticipated cost of intervention.
“The system balances the influence of the six criteria to determine the top health priorities by modulating the 'severity’ criterion effect with that of the other five criteria. It also can accommodate more than six criteria and weight each criterion differently, if necessary,” says Simoes.
In his study in Italy, for example, Simoes determined that physical inactivity, cigarette smoking and hypertension should be the highest priorities for intervention programs in Italy. With this information, he says Italian public health officials can begin to develop prevention programs before a risk factor or condition becomes widespread. Already, Simoes says, Italian public health officials have used the model to identify geographical “hot spots” for alcohol prevention.
Implementation of his model in Italy has generated interest from public health agencies around the world, Simoes says. Among these is his birthplace, Brazil, where Simoes says plans are already in place to begin work with the Ministério da Saúde, the national Ministry of Health.
Simoes would like to see greater use of the prioritization approach because it may simplify the decision-making process. He cites prostate cancer as an example of how it would work.
“Back in 1998, I used prostate cancer to make the case with the Missouri Department of Health to say, listen, prostate cancer is a very important disease when you look at the incidence of death among men in the state of Missouri, especially if you’re older than 65,” Simoes says.
“Nevertheless, there’s no public health intervention that’s recommended to this day. So the priority ranking of prostate cancer will be lowest possible for the intervention effectiveness amongst all chronic diseases and conditions.” Why? Because, Simoes says, evidence-based public health data did not — and still doesn’t — indicate that doing mass screening for prostate cancer is beneficial.
“This model of prioritization and how it works is so simple that it hurts,” Simoes says. “Let’s look at how big the issue is and how fast it’s moving.”
Cardiovascular disease has been the chief killer of Americans for the past 40 or 50 years, he says. “But the trend is down for most cardiovascular-attributed deaths in past 10 years. Though its priority is still high when you look at the size of the disease, its urgency should not be as high because the death-related trend is going down.”
Urgency of action may also depend on levels of community support, or the lack thereof. Simoes cites smoking and gun violence to make the point.
Knowing that tobacco use is major cause of chronic illness, and that banning smoking inside restaurants and bars keeps people healthier, is not necessarily enough to recommend that a given public health agency devote a lot of time and money lobbying for a ban. If the available data indicate community members and their elected representatives in, say, a tobacco-producing area, are intractably opposed to tobacco restrictions, resources might best be directed elsewhere — at least in the short term.
The issue of deaths and injuries related to gun violence is even more fraught. “If a community doesn’t like some ideas about an intervention around gun control, for example, because most members support the National Rifle Association, there’s no way in the world I can get support from the mayor and community leadership in adopting any intervention that relates to … creating a policy that restrains guns,” Simoes says.
Before Simoes introduced his behavioral risk prioritization model, other models on risk behavior existed. These used national and international data on risk behaviors but, according to Bert Malone, Simoes’ version made it much easier to access and process local data.
“This was the first time we, in Missouri, could more easily access this data and get a better reflection of what the true burden of disease would be in our communities,” Malone says. In the past, the issues Simoes explored have been examined in isolation or, at best, using a couple of criteria. Simoes’ model, Malone says, does the job of pulling all relevant criteria together.
Simoes compares it to a self-exam. “It allows a county, state, or region to do their own prioritization without concern of another county or state’s status,” he says. “It’s like looking at yourself in the mirror and doing a self-examination of your neck or breast for potential breast cancer. This doesn’t concern itself with a comparison to anyone else. The model allows you to be different.”
In the end, he adds, this is what it all boils down to: Helping health administrators at every level use their own resources more wisely.
“The model allows you to identify hot areas where a risk factor priority score is highest,” he says. “It allows a county in Missouri to tell the CDC and the DHSS, ‘I think you need to allow us to take our scarce resources and put them into this area.’ By doing that we lower the local rates and reach our goals for the whole state, as opposed to spreading our resources across 115 different counties with minimal or no impact.”


The benefits of Vaping Health
A new study suggests that electric cigarettes may be just what the doctor ordered. Smoking, especially used smoking can cause plenty of damage to your system. It causes the spread of certain cancers and other dreadful diseases. One particular disease is lung cancer. While it holds true that smoking is bad for your body overall, it could be good for your lungs to test e-cigs.
Nicotine in tobacco smoke has been proven to be highly toxic to human life. It causes plenty of cancers and other diseases. It also increases the threat of developing heart disease. It really is well documented that nicotine is an addicting drug. The nicotine levels in cigarettes are slowly ramped up as you smoke more. This increased degree of nicotine has proven to be one of the greatest known reasons for the increase in cigarette smoking.
You can find other health advantages to smoking fewer cigarettes with e-cigs. To begin with, there are no carcinogens or other harmful chemicals found in vaporized tobacco. Actually, you can find more helpful ingredients found podsmall in e-cigs. You can find none of the carcinogens within smoke and tar. E-cigs help people quit the bad habit of smoking.
Lots of people find that quitting the harmful habit takes years. However, quitting is not the only benefit to vapes. By firmly taking a puff of an electronic cigarette, you will help rid the body of toxins that cigarettes took from you. You can be healthier in an exceedingly short amount of time. This is probably one of many reasons to go for the e-juice vaporizers over the cigarette smoking machines.
Should you be concerned about the possible health threats that e-cigs may have, you should research them further. The electronic cigarettes do not contain the harmful chemicals found in regular cigarettes, so they are considered much safer compared to the normal cigarettes. A lot of the reports concerning the possible dangers of smoking are not only predicated on false claims, but also due to poor research.
With all of the new findings on the unwanted effects of smoking, we are able to expect a major decline in the sales of the cigarettes in the future. People are turning to a thing that is healthier, and the best way to get to stop smoking is by using an electronic device that does not release any dangerous toxins into the air. When you make the switch to smoking e-cigs, you will discover that you will not only become a healthier person, but additionally healthier in the wallet.
Another reason to take into account vaporizing instead of smoking is the fact that you will save a lot of cash. Most smokers expect to pay hundreds of dollars per month on cigarettes just to be able to put out a nice, even ash-filled smoke for one or two hours each day. You will be surprised to know how much money you truly save by using an electronic cigarette. It may appear to be a lot at first, however when you break it down, you will see that it is a great investment over time. Many people who have been ex-smokers and vapers for five or even more years can testify to the fact that once they made the change, they never returned to using tobacco.
One more reason to choose e-cigarette smoking over regular cigarettes is the fact that you can find no side effects. There are thousands of different chemicals along with other ingredients that go in to the manufacturing of regular cigarettes, but none of them produce any harmful side effects. On the other hand, e-juices do not contain any harmful chemicals, so that you can breathe easy each and every time you take a puff. That is great news for those who have problems with asthma or other respiratory problems. Electronic cigarettes are a perfect way to kick the bad habit and stay healthy for longer.


Tagged: 17, fluent, fluid-dynamics, General, General - FLUENT
January 25, 2023 at 7:16 amFAQParticipant
It is possible for SOFC to complete a SOEC analysis using the module. SOEC stands for solid oxide electrolysis cells. The following reaction will occur: 2H2O-> 2H2 + O2 The calculation method is very similar to SOEC. The sign of the current value should be set to negative or set the cell voltage greater than the open circuit voltage. It is also set up in the same manner in both the SOFC and SOEC analysis. Also, please note: 1.Voltage-tap is the hydrogen side, current-tap is set to the oxygen side 2.Anode is the hydrogen side, cathode is set to the oxygen side
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Postprocessing on Ansys EnSight
This video demonstrates exporting data from Fluent in EnSight Case Gold format, and it reviews the basic postprocessing capabilities of EnSight.
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Jeff Schmaltz, MODIS Rapid Response Team, NASA/GSFC
A dark gray pall of haze filled the skies over much of southeastern China on November 30, 2003, while more than a dozen fires (red pixels) dotted the landscape around Hong Kong. (The black polygon toward the bottom center of this scene shows Hong Kong’s location.) The coastal waters along Southeast Asia appear turquoise and tan, probably due to sediment-laden river discharge as well as bottom sediments being churned by the series of cyclones that have passed through the Western Pacific in recent weeks. This Moderate Resolution Imaging Spectroradiometer (MODIS) image was captured by the Aqua satellite.
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Nutrients are smaller scale supplements. They were found by Eijkman (1897) in Indonesia, Java, while examining an illness called beriberi regular among locals whose principle diet was rice. He saw that fowl benefited from cleaned rice, created beri, however not when benefited from roughly processed rice.
In 1911 Funk got a heavy drinker concentrate of the external husk of rice which restored beri. This was believed to be a crucial amine presenting the name vitamine. The “e” was later dropped to peruse “nutrient”.
Nutrients Functions And Sources:
As smaller scale supplements, vitamine d kopen are required in little amounts. For the most part your body can’t produce or integrate nutrients without any preparation. So you have to get them from the food you eat or from supplement pills. However, nutrients can be incorporated by certain microbes, yeast, form, green growth and some plant species. A few nutrients like nutrient B5 have been seen as orchestrated by microscopic organisms in the human internal organs. Anyway it isn’t clear if the nutrients are accessible for ingestion and use by the body.
Nutrients are required by the body for an assortment of organic procedures. These incorporate development e.g Vitamin B6; mental readiness e.g Choline, Niacin; protection from contamination for example Nutrient C and Vitamin E. They likewise go about as impetuses in the body science just as forerunners to imperative body factors. This empowers the body to utilize starches, fats and proteins.
Nutrients in themselves don’t have calories and along these lines don’t offer vitality to the body. Common nutrients are found in living things that is plants and creatures and are natural food substances. There are numerous misleadingly orchestrated nutrients.
Nutrients exist in shifting amounts in a variety of food sources from yeasts, wheat grain, cooked egg that gives Biotin, citrus products of the soil that give Vitamin C, green verdant vegetables and vegetables that flexibly Folic corrosive .
There are basically two sorts of nutrients grouped dependent on their solvency. These are water solvent and fat dissolvable nutrients.
I) Water solvent nutrients incorporate : Vitamin C additionally called citrus extract, Vitamin B1 (thiamine), Vitamin B2 (Riboflavin), Vitamin B3 (niacin), Vitamin B5 (pantothenic corrosive), Vitamin B9 (folic corrosive), Vitamin B6 (pyridoxine), Vitamin B12 (cobalamin), Cholin, Biotin.
Water solvent nutrients are not put away in the body in any obvious sums. The overflow is cleaned out essentially through pee. They requires steady recharging utilizing the eating regimen we devour. This makes them safe since they don’t gather in the body harmful levels, making huge portions of nutrient valuable safe. In any case, alert should in any case be polished in light of the fact that super portions have reactions and even can be deadly.
For instance, there is an okay of nutrient poisonousness from nicotinic corrosive with uber portions. Nicotinic corrosive a subsidiary of nutrient niacin, one may encounter flushing, tingling, queasiness and retching, liver cell harm. So supplement with day by day esteem dosages. Try not to utilize megadoses except if under continuous master counsel.
ii)Fat dissolvable nutrients incorporates: Vitamin A, Vitamin D, Vitamin E and Vitamin K. Being fat dissolvable these nutrients are put away in the fat in our bodies. They can without much of a stretch aggregate to harmful levels so on the off chance that you decide to enhance be careful.
The absence of these food factors i.e nutrients results to insufficiency sicknesses. Nutrient defiency maladies are an appearance of failing bio-synthetic procedures because of absence of the essential nutrients. Since a similar nutrient might be utilized in various procedures, inadequacy in certain nutrients can be very genuine and even lethal. For instance more than 200 compounds require the niacin nutrient coenzyme. So an absence of niacin makes this 200 compounds breakdown.
Nutrient lacks have been related with long haul idle inadequacy ailments. These ailments happen after quite a while of insufficiency of some nourishing components like nutrients. Long haul inactive insufficiency illnesses can be as extreme as malignant growth, diabetes and coronary illness. In our general public today, these infections are turning into the most noteworthy wellbeing concern.
The circumstance is grave since they are preventable as well as efficiently preventable. An appropriate nourishment is everything necessary to get every single required supplement including adequate amounts of nutrients. General medical advantages of nutrients incorporate security from an assortment of sicknesses and conditions.
In the event of a healthful hole between what your body and what your eating routine gives, enhancing is fundamental.
Entire nourishments are and will consistently be the best wellspring of nutrients. This is on the grounds that entire nourishments give a mix of supplements to the body including minerals and phytonutrients.
Be that as it may, numerous individuals don’t get all supplements they need from their food decisions. Either in light of the fact that they can’t or won’t eat enough, or they can’t or won’t eat right nourishments. This might be a direct result of clinical or states of being, your ways of life, for example work, time, accessibility or even because of neediness. In such cases, supplementation is fundamental.
The present ways of life make it increasingly important to enhance our eating regimens. There are gatherings of individuals to whom enhancing may truly not be a decision.
This will incorporate you if;
I) You are sixty five years and more established:- At this age a few nutrients are not effortlessly consumed by your body framework. Multivitamins may improve your insusceptibility and lower danger of certain contaminations.
ii) You are a post menopausal lady:- Supplement with calcium and nutrient D to help against osteoporosis.
iii) You don’t eat the suggested five servings of foods grown from the ground a day.
iv) You are on a low calorie diet. For example You are attempting to get more fit
v) You smoke – The tobacco meddles and decreases nutrient take-up of nutrients like nutrient B6, nutrient C, folic corrosive and even niacin.
Ps: This won’t compensate for the wellbeing danger of smoking.
vi) You drink exorbitantly that is in excess of a jug a day. Long haul unnecessary drinking will diminish assimilation of nutrients. Nutrients influenced are thiamin (Vitamin B), Folic corrosive, Vitamin An and D, just as Vitamin B12.
vii) You are pregnant or attempting to be pregnant.
There is a wide decision of nutrient enhancements in the business sectors to look over. While picking nutrients, think about the accompanying:-
a) Bioavailability of the nutrient: Choose nutrients supplements whose wellspring of fixings is from the human natural way of life. Numerous nutrients are separated from “common sources”, like green growth, which we don’t ordinarily eat. This may not be effectively accessible to your body.
b) Wide range of nutrients: Prefer to utilize multivitamins that give various emphatically interfacing nutrients. Recall that we require all supplements in changing amounts. It is smarter to have a multivitamin giving day by day esteems rather than megadoses of a solitary or not many nutrients.
c) Expiry date of the nutrient: Vitamins do terminate. Purchase to utilize just for the month. At the point when you need more you can generally buy once more.


Collaborative robots have grown in popularity and acceptance in manufacturing companies as they usher the industry into a new era. The era of human and robots working together rather than separately. The era of flexibility, accuracy and high quality products and faster adaptability to consumer preferences and market changes.
Collaborative robots used in robot assembly by the numerous manufacturing companies are categorized into four according to the International Standards Organization, ISO 10218. These categories are: Power and Force Limiting, hand guiding, speed and separation and safety monitored stop.
Collaborative robots that fall in this category are considered the safest collaborative robots for any factory to have. They can work alongside human workers without the risk of causing an accident in the factory. They do not require vision capabilities or caging. They are the ultimate collaborative robot.
Why is this so?
The answer to this question and the reason for this categorization lies in their design and safety features. Cobots in this category are designed with round edges and are completely smoothened. In addition, they are padded to ensure that the impact of an accident is minimal.
Further, these cobots have different types of super sensitive sensors that prevent accidents. These sensors have the ability to detect and predict a collision forcing the cobot to stop before it comes into contact with anything or anyone. These sensors are implanted in the cobots, giving them the capability to comfortably collaborate with human workers without the need for external attachments for this capabilities.
As the name suggests, this category represents collaborative robots that can be taught how to perform certain tasks using hand motions.
This happens especially when there is an urgent need to reprogram the cobot to perform a certain task. The worker holds the cobot and guides it through the correct positions of completing a particular task successfully.
Cobots in this category save time when it comes to programming enabling the factory to run continuously with minimal downtime.
It is important that cobot operators observe safety at all times especially when hand guiding a cobot without power and force limiting features.
Collaborative robots in this category are usually not in frequent contact with human workers. Safety monitored robots usually are large industrial robots that work independently but also require human input for their work to be successfully completed.
Robots in this category are affixed with an external senor that identifies when a human worker is in its working area. When it detects a human in its working area it will stop immediately to reduce any risk of accidents occurring. It will not start up until the human operator starts it by pressing a button for it to resume working.
Collaborative robots in this category are similar to those in the safety monitored stop category. The only difference is that, these robots have frequent interaction with human workers in the factory.
Just like those in the previous category they are also fitted with external apertures for vision and sensors. Unlike the safety monitored stop cobot, this cobot has two levels of security for the human operator working with it.
The first level can be described as a warning zone. When it detects a human worker in its warning zone, the robot slows down its activity.
The second level is the stop zone. When a human operator gets into the stop zone, the robot automatically stops operating.
Unlike the safety monitored stop cobot, this cobot resumes operation as soon as the human operator exits the stop zone.
As you can see, these cobot types are categorized on how safe they are to be used as collaborative robots. It is important for all companies that use robots to ensure that they know what risks they pose to their human workers and engage them appropriately by ensuring the correct safety standards are maintained.


Online Resources for Families Coping with Anxiety During Covid
Below are some useful articles and resources for parents and teenagers and young adults to cope with the added anxiety of living during this pandemic.
CRISIS TEXTLINE FOR TEENS/YOUNG ADULTS
Tips for Helping your Teen or Young Adult during Covid-19
--Encourage your teen/young adult to keep in regular contact with his mental health providers via telephone or online appointments.
--Make sure prescriptions are filled and up to date.
--Minimize access to "news" for it can be very stressful. Consider a "news fast".
--Keep routines going: get dressed everyday, exercise.
--Engage in family activities: eat at least one meal a day together; play board games or puzzles watch movies and tv as a family; go on walks with each other.


Signing: Start with an open hand, with your index finger touching your thumb. (as if daintily holding a tea cup) Hold your index finger and thumb by the side of your lips, while moving the rest of your hand backwards and forwards.
The sign for fruit is based on the sign for the letter F.
Usage: Wait until baby is a little older before teaching collective words like fruit. In the early days, I will instead use more specific words for the exact fruit I am referring to, like apple. Babies find it easier to conceptualize the specific. However, it is cognitively valuable to eventually start giving them examples of using a collective word, like fruit, that can refer to lots of different types of an object.
Flash Card: Click the link to view the Fruit Baby Sign Language Flash Card. The flash cards are printable and available in both U.S. Letter and A4 sizes.


Wayne R. Scott with Dane Bundy
Who rules the universe? Chance or God? I looked at these questions in my last post.
In this post, I’d like to trace the themes of chance and God’s sovereignty through three stories.
In the newest Avenger’s film–Infinity Wars, we’re told that chance had a place in the origin of the universe. Jason Wong, the friend of Dr. Strange and fellow-protector of the Time Stone, offers an explanation of how the universe came into being,
“At the dawn of the universe, there was nothing…then…boom. The Big Bang sent six elemental crystals…hurtling across the virgin universe.”
If chance — and not intelligence — brought the universe into existence, how might that affect the people who live in it? If chance rules the universe, can anything in it, including human beings, have real significance or meaning?
Waiting for Godot
To consider the last question (Can chance bring about meaning?), I’m going to point you to the modern classic Waiting for Godot (debuted 1953), written by the Nobel Prize-winning author Samuel Beckett. The plot of this play is terribly simple.
Two men wait — the entire play — for a man named Godot to arrive. But Godot doesn’t arrive and the play ends.
Sound a little bleak and nonsensical? That’s the point. I think Beckett’s making the existential point that our reliance upon God (“Godot”), or the Judeo-Christian worldview or the ideas underlying the West, has gotten us nowhere.
God is not arriving to solve our problems; the universe is nonsensical, without meaning. Would you pay the price of a ticket to see a play in which the whole point is that the universe has no point?
We’re going to shift back some centuries. As times change, so do ideas about the world. These ideas ultimately filter into culture, including the arts. Here’s an example from my favorite play, Hamlet.
Written during the Reformation era, Shakespeare believed the world was not ruled by chance but by God. Hamlet makes the following statements:
“There’s a divinity that shapes our ends” (Act 5 Scene 2).
“[T]here is special providence in the fall of a sparrow” (Ibid.).
While at times Hamlet wasn’t pleased with God’s sovereignty, he always feared it. God’s involvement in the universe gave Hamlet a meaningful structure to live by.
Do you see the shift in thinking that has taken place from Hamlet to Avengers?
Can You Think of Other Examples?
This is an excerpt from “Phantom of the Opera From a Christian Perspective.” Read the full article.
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