Protein-rich diet may help soothe inflamed gut

Immune cells patrol the gut to ensure that harmful microbes hidden in the food we eat don't sneak into the body. Cells that are capable of triggering inflammation are balanced by cells that promote tolerance, protecting the body without damaging sensitive tissues. When the balance tilts too far toward inflammation, inflammatory bowel disease can result.

Now, researchers at Washington University School of Medicine in St. Louis have found that a kind of tolerance-promoting immune cell appears in mice that carry a specific bacterium in their guts. Further, the bacterium needs tryptophan - one of the building blocks of proteins - to trigger the cells' appearance.

"We established a link between one bacterial species - Lactobacillus reuteri - that is a normal part of the gut microbiome, and the development of a population of cells that promote tolerance," said Marco Colonna, MD, the Robert Rock Belliveau MD Professor of Pathology and the study's senior author. "The more tryptophan the mice had in their diet, the more of these immune cells they had."

If such findings hold true for people, it would suggest that the combination of L. reuteri and a tryptophan-rich diet may foster a more tolerant, less inflammatory gut environment, which could mean relief for the million or more Americans living with the abdominal pain and diarrhea of inflammatory bowel disease.

A representation of the 3D structure of the protein myoglobin showing turquoise α-helices. By AzaToth (self made based on PDB entry) [Public domain], via Wikimedia Commons

Postdoctoral researcher Luisa Cervantes-Barragan, PhD, was studying a kind of immune cell that promotes tolerance when she discovered that one group of study mice had such cells, while a second group of study mice that were the same strain of mice but were housed far apart from the first group did not have such cells.

The mice were genetically identical but had been born and raised separately, indicating that an environmental factor influenced whether the immune cells developed.

She suspected the difference had to do with the mice's gut microbiomes - the community of bacteria, viruses and fungi that normally live within the gastrointestinal tract.

Cervantes-Barragan collaborated with Chyi-Song Hsieh, MD, PhD, the Alan A. and Edith L. Wolff Distinguished Professor of Medicine, to sequence DNA from the intestines of the two groups of mice. They found six bacterial species present in the mice with the immune cells but absent from the mice without them.

With the help of Jeffrey I. Gordon, MD, the Dr. Robert J. Glaser Distinguished University Professor, the researchers turned to mice that had lived under sterile conditions since birth to identify which of the six species was involved in inducing the immune cells. Such mice lack a gut microbiome and do not develop this kind of immune cell. When L. reuteri was introduced to the germ-free mice, the immune cells arose.

To understand how the bacteria affected the immune system, the researchers grew L. reuteri in liquid and then transferred small amounts of the liquid - without bacteria - to immature immune cells isolated from mice. The immune cells developed into the tolerance-promoting cells. When the active component was purified from the liquid, it turned out to be a byproduct of tryptophan metabolism known as indole-3-lactic acid.

Tryptophan - commonly associated with turkey - is a normal part of the mouse and the human diet. Protein-rich foods contain appreciable amounts: nuts, eggs, seeds, beans, poultry, yogurt, cheese, even chocolate.

When the researchers doubled the amount of tryptophan in the mice's feed, the number of such cells rose by about 50 percent. When tryptophan levels were halved, the number of cells dropped by half.

People have the same tolerance-promoting cells as mice, and most of us shelter L. reuteri in our gastrointestinal tracts. It is not known whether tryptophan byproducts from L. reuteri induce the cells to develop in people as they do in mice, but defects in genes related to tryptophan have been found in people with inflammatory bowel disease.

"The development of these cells is probably something we want to encourage since these cells control inflammation on the inner surface of the intestines," Cervantes-Barragan said. "Potentially, high levels of tryptophan in the presence of L. reuteri may induce expansion of this population."

For more information visit:-

https://www.sciencedaily.com/releases/2017/08/170803141045.htm

https://en.wikipedia.org/wiki/Protein

http://www.prlabs.co.uk/lab-supplies.php?N=300l-msia-darts-protein-a&Id=19590

Mice with missing lipid-modifying enzyme heal better after heart attack

Two immune responses are important for recovery after a heart attack - an acute inflammatory response that attracts leukocyte immune cells to remove dead tissue, followed by a resolving response that allows healing.

The human heart by Patrick J. Lynch, medical illustrator (Patrick J. Lynch, medical illustrator) [CC BY 2.5 (http://creativecommons.org/licenses/by/2.5)], via Wikimedia Commons

Failure of the resolving response can allow a persistent, low-grade nonresolving inflammation, which can lead to progressive acute or chronic heart failure. Despite medical advances, 2 to 17 percent of patients die within one year after a heart attack due to failure to resolve inflammation. More than 50 percent die within five years.

Using a mouse heart attack model, Ganesh Halade, Ph.D., and his University of Alabama at Birmingham colleagues have shown that knocking out one particular lipid-modifying enzyme, along with a short-term dietary excess of a certain lipid, can improve post-heart attack healing and clear inflammation. Halade, an assistant professor in the UAB Department of Medicine, hopes that future physicians will be able to use knowledge from studies like his to boost healing in patients after heart attacks and prevent heart failure.

"Our goal is healing, and we are reaching that goal," he said of efforts in the UAB Division of Cardiovascular Medicine.

Why are lipids and lipid-modifying enzymes important in inflammation and resolving inflammation? Three key lipid modifying enzymes in the body change the lipids into various signaling agents. Some of these signaling agents regulate the triggering of inflammation, and others promote the reparative pathway.

The lipids modified by the enzymes are two types of essential fatty acids that come from food, since mammals cannot synthesize them. One is n-6 or omega-6 fatty acids, and the other type is n-3 or omega-3 fatty acids. The balance of these two types is important.

The Mediterranean diet, with a near balance of omega-3 and omega-6 fatty acids, promotes heart health. The Western diet, with large amounts of omega-6 fatty acids that greatly exceed the levels of omega-3 fatty acids, can lead to heart disease.

The three main lipid-modifying enzymes compete with each other to modify whatever fatty acids are available from the diet. So, Halade and colleagues asked, what will happen if we knock out one of the key enzymes, the 12/15 lipoxygenase?

They reasoned that this would increase the metabolites produced by the other two main enzymes, cyclooxygenase and cytochrome P450 because they no longer had to compete with 12/15 lipoxygenase for lipids to modify. This might be a benefit because those signaling lipids produced through the cyclooxygenase and cytochrome P450 pathways were already known to lead to major resolution promotion factors for post-heart attack healing.

The UAB researchers found that knocking out the 12/15 lipoxygenase and feeding the mice a short-term excess of polyunsaturated fatty acids led to increased leukocyte clearance after experimental heart attack, meaning less chronic inflammation. It also improved heart function, increased the levels of bioactive lipids during the reparative phase of healing, and led to higher levels of reparative cytokine markers. Additionally, the heart muscle showed less of the fibrosis that is a factor in heart failure.

Besides congestive heart failure, persistent inflammation aggravates a vicious cycle in many cardiovascular diseases, including atherogenesis, atheroprogression, atherosclerosis and peripheral artery disease.

Halade says further mechanistic studies are warranted to develop novel targets for treatment and to find therapies that support the onset of left ventricle healing and prevent heart failure pathology.

For more information visit:-

https://www.sciencedaily.com/releases/2017/05/170501142547.htm

https://commons.wikimedia.org/wiki/File:Heart_anterior_exterior_view.jpg

http://www.prlabs.co.uk/lab-supplies.php?N=enzyme-mix-long-pcr-100-units-5ul&Id=11608

Simple fats, amino acids to explain how life began

Life is a process that originated 3.5 billion years ago. It emerged when the basic components of the cells that we know today, in other words, inanimate chemical molecules, gradually joined, merged, assembled themselves and interacted. At a given moment they became alive, or what amounts to the same thing, they turned into autonomous systems. As the years passed they gradually evolved until achieving their current complexity and diversity. A piece of research by the UPV/EHU is working on the start of this trajectory by studying how the chemical molecules assembled themselves so that life could begin.

A section of DNA. Zephyris at the English language Wikipedia [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0/)], via Wikimedia Commons

DNA, RNA, proteins, membranes, sugars, …cells are made up of all kinds of components. In biology, and in the studies dealing with the origin of life specifically, it is very common to focus on one of these molecules and put forward hypotheses on how life originated by analysing the specific mechanisms related to it. "Basically, these studies are looking for the 'molecule of life', in other words, they set out to establish which was the most important molecule in making this milestone happen," said Kepa Ruiz-Mirazo, researcher in the Biophysics Unit and of the UPV/EHU's Department of Logic and Philosophy of Science. However, bearing in mind that "life involves activity among a huge variety of molecules and components, a change of approach has been taking place in recent years and research that takes into account various molecules at the same time is gaining strength," he added.

Besides emerging in favour of this fresh approach, Ruiz-Mirazo's group, in collaboration with the University of Montpellier, through an internship of the UPV/EHU PhD student Sara Murillo-Sánchez, has been able to show that interaction exists between some molecules and others. "Our group has expertise in research into membranes that are created in prebiotic environments, in other words, in the study of the dynamics that fatty acids, the precursors of current lipids, may have had. 

The Montpellier group for its part specialises in the synthesis of the first peptides. So when the knowledge of each group is put together, and when we experimentally blended the fatty acids and the amino acids, we could see that there was a strong synergy between them."

As they were able to see, the catalysis of the reaction took place when the fatty acids formed compartments. As they are in an aqueous medium, and due to the hydrophobic nature of lipids, they tend to join with each other and form closed compartments; in other words, they take on the function of a membrane; "at that time the membranes obviously weren't biological but chemical ones," explained Ruiz-Mirazo. In their experiments they were able to see that the conditions offered by these membranes are favourable for amino acids. "The Montpellier group had the prebiotic reactions of the formation of dipeptides very well characterised, so they were able to see that this reaction took place more efficiently in the presence of fatty acids," he added.

Besides demonstrating the synergy between fatty acids and amino acids, Ruiz-Mirazo believes it is very important to have conducted the study using basic chemical components, in other words, molecular precursors. "Life emerged out of these basic molecules; therefore, to study its origin we cannot start from the complex phospholipids that are found in today's membranes. We have demonstrated the formation of the first coming together and formation of chains on the basis of molecular precursors. Or to put it another way, we have demonstrated that it is possible to achieve diversity and complexity in biology by starting from chemistry."

In his studies, in addition to the experimental work, Ruiz-Mirazo is working in another two spheres so in the end he is studying the origin of life from three pillars or perspectives: "firstly, we have the experimental field; another is based on theoretical models and computational simulations, which we use to analyse the results obtained in the experiments, and the third is a little broader, because we are studying from the philosophical viewpoint what life is, the influence that the conception held about life exerts on the experimental field, since each conception leads you to carry out a specific type of experiment," he explained. "These three methodologies mutually feed each other: an idea that may emerge in the philosophical analysis leads you to carry out a new simulation, and the results of the simulations mark out the path for designing the experiments. Or the other way round. Most likely we will never manage to find the answer to how life began, but we are working on it: all of us living beings on Earth have the same origin and we want to know how it happened."

For more information visit:-

https://www.sciencedaily.com/releases/2017/01/170112083719.htm

http://www.prlabs.co.uk/lab-supplies.php?N=300l-msia-darts-protein-ag&Id=19593

Air pollution causes wrinkles and premature ageing, new research shows

Air pollution is prematurely ageing the faces of city dwellers by accelerating wrinkles and age spots, according to emerging scientific research.

The effects of toxic fumes on skin are being seen in both western cities, such as London and New York, as well as in more visibly polluted Asian cities and in some cases may be the primary cause of ageing. The pollution is also being linked to worsening skin conditions such as eczema and hives.

The scientific discoveries are now driving the world’s biggest cosmetics companies to search for solutions, including medicine-like compounds that directly block the biological damage. But doctors warn that some common skin care routines, such as scrubs, make the damage from air pollution even worse.

Poisonous air is already known to cause millions of early deaths from lung and heart diseases and has been linked to diabetes and mental health problems. But perhaps its most visible impact, the damage caused to skin, is just beginning to be understood.

“With traffic pollution emerging as the single most toxic substance for skin, the dream of perfect skin is over for those living and working in traffic-polluted areas unless they take steps to protect their skin right now,” said Dr Mervyn Patterson, a cosmetic doctor at Woodford Medical clinics in the UK.

“Unless people do more they will end up wearing the pollution on their faces in 10 years’ time. It is definitely something people now need to take seriously.”

Nitrogen dioxide diffusion tube for air quality monitoring.By Etan J. Tal, via Wikimedia Commons.

Prof Jean Krutmann, director at the Leibniz Research Institute for Environmental Medicine in Germany, said: “UV [damage from the sun] was really the topic in skin protection for the last 20-30 years. Now I think air pollution has the potential to keep us busy for the next few decades.”

Air pollution in urban areas, much of which comes from traffic, includes tiny particles called PMs, nitrogen dioxide (NO2) and chemicals such as polycyclic aromatic hydrocarbons (PAHs). “What is very clear is that PMs are a problem for skin,” said Krutmann, whose work has shown PMs increase age spots and wrinkles.

But one of the his newest studies showed NO2 also increases ageing. They studied people in both Germany and China and discovered that age spots on their cheeks increased by 25% with a relatively small increase in pollution, 10 microgrammes of NO2 per cubic metre. Many parts of the UK have illegally high levels of NO2, with London breaking its annual limit in the first week of 2016, with levels reaching over 200 microgrammes of NO2 per cubic metre.

Krutmann said other factors, such as UV exposure, nutrition and smoking contribute to ageing: “But what we can say is that, at least for the pigment spots on the cheeks, it seems air pollution is the major driver.”

“It is not a problem that is limited to China or India – we have it in Paris, in London, wherever you have larger urban agglomerations you have it,” he said. “In Europe everywhere is so densely populated and the particles are being distributed by the wind, so it is very difficult to escape from the problem.”

The accelerated skin ageing was seen in relatively young people and Patterson said: “If you are seeing these changes in middle age, these are worrying trends.”

Other recent research is summed up in a review paper in the journal Frontiers in Environmental Science, which concluded: “Prolonged or repetitive exposure to high levels of these [air] pollutants may have profound negative effects on the skin.”

Understanding exactly how air pollution causes the skin damage is at an early stage, according to Krutmann: “We are just now dipping into the mechanisms.” But many of the pollutants are known to pass easily through the skin and cause a variety of impacts.

“These agents have a very irritating effect and once they get into the skin, they activate multiple pathways of inflammation,” said Patterson. “Some pathways ignite the melanocytes, which create far too much pigment and end up giving you unwanted sun spots.”

“Other pathways ignite messengers that make blood vessels grow, that’s what results in increased redness and potentially rosacea,” he said. “Also, if you damage skin, it goes into repair mode and excites enzymes which re-adsorb damaged collagen. When you have too much chronic inflammation, these enzymes remove more collagen than your skin can create. This produces skin laxity and that’s where fine lines and wrinkles come in.”

Dr Debra Jaliman, a skin expert based in New York City, says her patients are now worrying about the impact of air pollution on their skin, which she said can cause darkening of the skin and acne-like eruptions, as well as ageing.

“At the moment, there are not many products for prevention [of air pollution damage], however it may be a trend in the coming years as it becomes a much bigger issue,” she said.

Major beauty companies have begun their own research and are launching the first products formulated to battle skin damage from toxic air. Dr Frauke Neuser, senior scientist for Olay, a Procter and Gamble brand, has run studies showing significantly lower skin hydration in people living in polluted areas and lab studies showing that diesel fumes and PMs cause inflammation in skin cells.

Her team then screened for ingredients that could counteract some of the damaging effects. “We found niacinamide - vitamin B3 - to be particularly effective,” she said. “We have recently increased its level in several products by as much as 40%.”

Frauke’s work has also shown direct correlations between spikes in PM air pollution in Beijing and an increase in hospital visits by people with skin conditions including hives. “This indicates that not only skin ageing but also skin health are affected by air pollution,” she said.

L’Oreal, another cosmetics giant, published a medical study in 2015 showing that eczema and hives were more common in people in Mexico exposed to higher levels of air pollution, a conclusion supported by separate research in Canada. “The next step is to understand more deeply the environment-induced damages, in order to develop skin ageing prevention routines and products,” said Dr Steve Shiel, scientific director at L’Oreal.

Clinique, a big makeup brand, has already launched a sonic face cleansing brush it claims better removes pollution. “This [air pollution] is not going to go away. This is not a problem that is easily fixed,” said Janet Pardo at Clinique.

However, researchers are now working on medicine-like compounds that block the damage from air pollution from occurring in the first place. Krutmann’s lab helped Symrise, one of the world’s biggest suppliers of cosmetics ingredients, identify one, though the lab has no commercial stake in the product, which is called SymUrban.

“We found one molecule that can do the job,” he said, and it is now being registered as cosmetic ingredient. “In a few years from now I expect we will see cosmetic products that can specifically protect against skin ageing from air pollution.”

Patterson said it is possible for people to give themselves some protection now. “You don’t have to sit back passively and put up with it. You can take sensible, easy steps that will make a difference.”

“If your skin is really healthy, it is quite a good barrier,” he said, explaining that the top layer is like a roof - flattened cells like tiles separated by protective lipids.

“Certain skin care products are very disruptive to the surface of the skin,” he warned. “So a darling of the industry is retinoids, but these have a very profound negative effect on barrier function. Another darling of the industry is glycolic acid, but it is also very disruptive to the external skin barrier. People think these are good skin care, making the skin look smoother, but they are not helpful for the overall health of the skin barrier.”

Patterson is also dismissive of face scrubs: “The skin is trying its damnedest to make this wonderful defence mechanism and what do women and men do? They scrub the hell out of it. It just doesn’t make sense.” He said products that help repair the skin barrier, by delivering the pre-cursor lipids the cells need, are beneficial, as are ones that tackle inflammation.

“You can also put on a very nice physical shield in the form of good quality mineral makeup,” he said. “That produces an effect like a protective mesh and probably has some trapping effect, protecting against the initial penetration of particles. But you also need always to try to remove that shield in the evening, washing the slate clean every night.”

For more information visit:-

https://www.theguardian.com/environment/2016/jul/15/air-pollution-causes-wrinkles-and-premature-ageing-new-research-shows

http://www.prlabs.co.uk/lab-supplies.php?N=total-nitrogen-lr-set&Id=61458

Unexpected discovery leads to a better battery

An unexpected discovery has led to a rechargeable battery that's as inexpensive as conventional car batteries, but has a much higher energy density. The new battery could become a cost-effective, environmentally friendly alternative for storing renewable energy and supporting the power grid.

A team based at the Department of Energy's Pacific Northwest National Laboratory identified this energy storage gem after realizing the new battery works in a different way than they had assumed. 

The journal Nature Energy published a paper today that describes the battery.

"The idea of a rechargeable zinc-manganese battery isn't new; researchers have been studying them as an inexpensive, safe alternative to lithium-ion batteries since the late 1990s," said PNNL Laboratory Fellow Jun Liu, the paper's corresponding author. "But these batteries usually stop working after just a few charges. Our research suggests these failures could have occurred because we failed to control chemical equilibrium in rechargeable zinc-manganese energy storage systems."

A range of different batteries

After years of focusing on rechargeable lithium-ion batteries, researchers are used to thinking about the back-and-forth shuttle of lithium ions. Lithium-ion batteries store and release energy through a process called intercalation, which involves lithium ions entering and exiting microscopic spaces in between the atoms of a battery's two electrodes.

This concept is so engrained in energy storage research that when PNNL scientists, collaborating with the University of Washington, started considering a low-cost, safe alternative to lithium-ion batteries - a rechargeable zinc-manganese oxide battery - they assumed zinc would similarly move in and out of that battery's electrodes.

After a battery of tests, the team was surprised to realize their device was undergoing an entirely different process. Instead of simply moving the zinc ions around, their zinc-manganese oxide battery was undergoing a reversible chemical reaction that converted its active materials into entirely new ones.

Liu and his colleagues started investigating rechargeable zinc-manganese batteries because they are attractive on paper. They can be as inexpensive as the lead-acid batteries because they use abundant, inexpensive materials (zinc and manganese). And the battery's energy density can exceed lead-acid batteries. The PNNL scientists hoped they could produce a better-performing battery by digging deeper into the inner workings of the zinc-manganese oxide battery.

So they built their own battery with a negative zinc electrode, a positive manganese dioxide electrode and a water-based electrolyte in between the two. They put small, button-sized test batteries through the wringer, repeatedly charging and discharging them. As others had found before them, their test battery quickly lost its ability to store energy after just a few charging cycles. But why?

To find out, they first performed a detailed chemical and structural analysis of the electrolyte and electrode materials. They were surprised to not find evidence of zinc interacting with manganese oxide during the battery's charge and discharge processes, as they had initially expected would happen. The unexpected finding led them to wonder if the battery didn't undergo a simple intercalation process as they had previously thought. Perhaps the zinc-manganese battery is less like a lithium-ion battery and more like the traditional lead-acid battery, which also relies on chemical conversion reactions.

To dig deeper, they examined the electrodes with several advanced instruments with a variety of scientific techniques, including Transmission Electron Microscopy, Nuclear Magnetic Resonance and X-Ray Diffraction. The instruments used were located at both PNNL and the Environmental Molecular Sciences Laboratory (EMSL), a DOE Office of Science user facility located at PNNL. 

Combining these techniques revealed manganese oxide was reversibly reacting with protons from the water-based electrolyte, which created a new material, zinc hydroxyl sulfate.

Typically, zinc-manganese oxide batteries significantly lose storage capacity after just a few cycles. This happens because manganese from the battery's positive electrode begins to sluff off, making the battery's active material inaccessible for energy storage. But after some manganese dissolves into the electrolyte, the battery gradually stabilizes and the storage capacity levels out, though at a much lower level.

The team used the new knowledge to prevent this manganese sluff-off. Knowing the battery underwent chemical conversions, they determined the rate of manganese dissolution could be slowed down by increasing the electrolyte's initial manganese concentration.

So they added manganese ions to the electrolyte in a new test battery and put the revised battery through another round of tests. This time around, the test battery was able to reach a storage capacity of285 milliAmpere-hours per gram of manganese oxide over 5,000 cycles, while retaining 92 percent of its initial storage capacity.

"This research shows equilibrium needs to be controlled during a chemical conversion reaction to improve zinc-manganese oxide battery performance," Liu said. "As a result, zinc-manganese oxide batteries could be a more viable solution for large-scale energy storage than the lithium-ion and lead-acid batteries used to support the grid today."

The team will continue their studies of the zinc-manganese oxide battery's fundamental operations. Now that they've learned the products of the battery's chemical conversion reactions, they will move on to identify the various in-between steps to create those products. They will also tinker with the battery's electrolyte to see how additional changes affect its operation.

This research was supported by DOE's Office of Science and used resources at the Environmental Molecular Sciences Laboratory (EMSL), a DOE Office of Science user facility located at PNNL.

For more information visit:-

https://www.sciencedaily.com/releases/2016/04/160418145631.htm#

http://www.prlabs.co.uk/lab-supplies.php?N=zinc-hydroxide-carbonate-pure-zinc-carb&Id=40515

On this day

On 8th January 1868, Søren Peder Lauritz Sørensen was born in Havrebjerg, Denmark.  He died on 12th February 1939.  He was a Danish chemist famous for the introduction of the concept of pH, a scale for measuring acidity and basicity.

From 1901 to 1938 he was head of the prestigious Carlsberg Laboratory, Copenhagen. While working there he studied the effect of ion concentration on proteins, and because the concentration of hydrogen ions was particularly important, he introduced the pH-scale as a simple way of expressing it in 1909.

The article in which he introduced the scale (using the notation pH), described two new methods for measuring acidity. The first method was based on electrodes, while the second involved comparing the colours of samples and a preselected set of indicators.

pH is a measure of the acidity or basicity of an aqueous solution. Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline. Pure water has a pH very close to 7.

For more information visit:-

http://en.wikipedia.org/wiki/PH

http://www.encyclopedia.com/topic/Soren_Peter_Lauritz_Sorensen.aspx

pH Indicators

A pH indicator is a colour changing (or halochromic) chemical compound that is added in small amounts to a solution so that the pH (acidity or basicity) of the solution can be determined visually.

A pH indicator is a chemical detector for hydronium ions (H3O+) or hydrogen ions (H+).  Normally, the indicator causes the colour of the solution to change depending on the pH.

pH (potential of hydrogen) is a scale of acidity from 0 to 14. It tells how acidic or alkaline a substance is. More acidic solutions have lower pH. More alkaline solutions have higher pH. Substances which are not acidic or alkaline (neutral) usually have a pH of 7. Acids have a pH less than 7. Alkalis have a pH greater than 7.

pH indicator solutions are themselves weak acids or bases.  As one chemical is added it changes the arrangement of the electrons in the molecule causing it to absorb different wavelengths of light and therefore appear different in colour.

Different chemicals can be used for different pH ranges as shown in the diagram below.

 

pH indicators are frequently employed in titrations in analytical chemistry and biology to determine the extent of a chemical reaction. Because of the subjective choice (determination) of colour, pH indicators are susceptible to imprecise readings. For applications requiring precise measurement of pH, a pH meter is frequently used.

Many plants or plant parts contain chemicals from the naturally-coloured anthocyanin family of compounds. They are red in acidic solutions and blue in basic. Anthocyanins can be extracted with water or other solvents from a multitude of coloured plants or plant parts, including from leaves (red cabbage); flowers (geranium, poppy, or rose petals); berries (blueberries, blackcurrant); and stems (rhubarb). Extracting anthocyanins from household plants, especially red cabbage, to form a crude pH indicator is a popular introductory chemistry demonstration.

For more information visit:-

http://en.wikipedia.org/wiki/PH_indicators

http://www.compoundchem.com/2014/04/04/the-colours-chemistry-of-ph-indicators/

 

Back to school

Where did the summertime break go?  Time for kids to go back to school.  And time for us too...chemistry basics.....Acids and bases

All acids:

• have a low pH (1-6) – the lower the number the stronger the acid
• react with bases to form neutral compounds
• are corrosive when they are strong
• are an irritant when they are weak.

Acids have a pH of less than 7. Bases have a pH of more than 7. When bases are dissolved in water, they are known as alkalis. Salts are made when an acid reacts with a base, carbonate or metal. The name of the salt formed depends on the metal in the base and the acid used. For example, salts made using hydrochloric acid are called chlorides.

Acids
Substances with a pH of less than 7 are acids. The more strongly acidic the solution, the lower its pH number. Acidic solutions turn blue litmus paper red. They turn universal indicator paper red if they are strongly acidic, and orange or yellow if they are weakly acidic.

Bases
Substances that can react with acids and neutralise them to make a salt and water are called bases. They are usually metal oxides or metal hydroxides. For example, copper oxide and sodium hydroxide are bases.

Alkalis
Bases that dissolve in water are called alkalis. Copper oxide is not an alkali because it does not dissolve in water. Sodium hydroxide is an alkali because it does dissolve in water.

Alkaline solutions have a pH of more than 7. The stronger the alkali, the higher the pH number. Alkalis turn red litmus paper blue. They turn universal indicator paper dark blue or purple if they are strongly alkaline, and blue-green if they are weakly alkaline.

Neutral solutions
Neutral solutions have a pH of 7. They do not change the colour of litmus paper, but they turn universal indicator paper green. Water is neutral.

For pH meters or pH test papers or buffer solutions give us a call.

For more information visit:-
http://www.prlabs.co.uk
http://en.wikipedia.org/wiki/PH

Hydrofluoric Acid

Hydrofluoric acid (HF) is a solution of hydrogen fluoride in water. It is a valued source of fluorine and is a precursor to numerous pharmaceuticals such as fluoxetine (Prozac) and diverse materials such as PTFE (Teflon).

Hydrofluoric acid is a highly corrosive acid, capable of dissolving many materials, especially oxides. Its ability to dissolve glass has been known since the 17th century, even before hydrofluoric acid had been prepared in large quantities by Carl Wilhelm Scheele in 1771. Because of its high reactivity toward glass and moderate reactivity toward many metals, hydrofluoric acid is usually stored in plastic containers (although PTFE is slightly permeable to it).

Hydrogen fluoride gas is an acute poison that may immediately and permanently damage lungs and the corneas of the eyes. Aqueous hydrofluoric acid is a contact-poison with the potential for deep, initially painless burns and ensuing tissue death. By interfering with body calcium metabolism, the concentrated acid may also cause systemic toxicity and eventual cardiac arrest and fatality, after contact with as little as 160 cm² (25 square inches) of skin.

Production
Hydrofluoric acid is produced by treatment of the mineral fluorite (CaF₂) with concentrated sulphuric acid. When combined at 265 °C, these two substances react to produce hydrogen fluoride and calcium sulphate according to the following chemical equation:

CaF₂ + H₂SO₄ → 2 HF + CaSO₄

Although bulk fluorite is a suitable precursor and a major source of world HF production, HF is also produced as a by-product of the production of phosphoric acid, which is derived from the mineral apatite. Apatite sources typically contain a few percent of fluoroapatite, acid digestion of which releases gaseous stream consisting of sulphur dioxide (from the H₂SO₄), water, and HF, as well as particulates. After separation from the solids, the gases are treated with sulphuric acid and oleum to afford anhydrous HF. Owing to the corrosive nature of HF, its production is accompanied by the dissolution of silicate minerals, and, in this way, significant amounts of fluorosilicic acid is generated.

Health & Safety

Hydrofluoric acid is a highly corrosive liquid and is a contact poison. It should be handled with extreme care, beyond that accorded to other mineral acids. Owing to its low dissociation constant, HF as a neutral lipid-soluble molecule penetrates tissue more rapidly than typical mineral acids. Because of the ability of hydrofluoric acid to penetrate tissue, poisoning can occur readily through exposure of skin or eyes, or when inhaled or swallowed. Symptoms of exposure to hydrofluoric acid may not be immediately evident. HF interferes with nerve function, meaning that burns may not initially be painful. Accidental exposures can go unnoticed, delaying treatment and increasing the extent and seriousness of the injury.

Once absorbed into blood through the skin, it reacts with blood calcium and may cause cardiac arrest. Burns with areas larger than 25 square inches (160 cm²) have the potential to cause serious systemic toxicity from interference with blood and tissue calcium levels. In the body, hydrofluoric acid reacts with the ubiquitous biologically important ions Ca²⁺ and Mg²⁺. Formation of insoluble calcium fluoride is proposed as the etiology for both precipitous fall in serum calcium and the severe pain associated with tissue toxicity. In some cases, exposures can lead to hypocalcemia. Thus, hydrofluoric acid exposure is often treated with calcium gluconate, a source of Ca²⁺ that sequesters the fluoride ions. HF chemical burns can be treated with a water wash and 2.5% calcium gluconate gel. or special rinsing solutions. However, because it is absorbed, medical treatment is necessary; rinsing off is not enough. Intra-arterial infusions of calcium chloride have also shown great effectiveness in treating burns.

P&R Labpak can supply HF antidote gel - just ask for details.

For more information visit:-
http://en.wikipedia.org/wiki/Hydrofluoric_acid
http://www.hse.gov.uk/pubns/indg307.pdf
This link covers HF poisoning, effects and precautions

Nitric Acid

Nitric acid (HNO₃), also known as aqua fortis and spirit of niter, is a highly corrosive strong mineral acid. The pure compound is colorless, but older samples tend to acquire a yellow cast due to the accumulation of oxides of nitrogen. Most commercially available nitric acid has a concentration of 68%. When the solution contains more than 86% HNO₃, it is referred to as fuming nitric acid. Depending on the amount of nitrogen dioxide present, fuming nitric acid is further characterized as white fuming nitric acid or red fuming nitric acid, at concentrations above 95%. Nitric acid is also commonly used as a strong oxidizing agent.

Contamination with nitrogen dioxide

 

Nitric acid is subject to thermal or light decomposition: 4 HNO₃ → 2 H₂O + 4 NO₂ + O₂. This reaction may give rise to some non-negligible variations in the vapor pressure above the liquid because the nitrogen oxides produced dissolve partly or completely in the acid.

Uses

The main use of nitric acid is for the production of fertilisers. Nitric acid is neutralised with ammonia to give ammonium nitrate. This application consumes 75-80% of the 26M tons produced annually (1987). The other main applications are for the production of explosives, nylon precursors, and specialty organic compounds.

Other Uses

As an analytical reagent - In elemental analysis by ICP-MS, ICP-AES, GFAA, and Flame AA, dilute nitric acid (0.5 to 5.0%) is used as a matrix compound for determining metal traces in solutions.  Ultrapure trace metal grade acid is required for such determination, because small amounts of metal ions could affect the result of the analysis.

It is also typically used in the digestion process of turbid water samples, sludge samples, solid samples as well as other types of unique samples which require elemental analysis.

In electrochemistry, nitric acid is used as a chemical doping agent for organic semiconductors, and in purification processes for raw carbon nanotubes.

Woodworking - In a low concentration (approximately 10%), nitric acid is often used to artificially age pine and maple. The color produced is a grey-gold very much like very old wax or oil finished wood

Etchant and cleaning agent - The corrosive effects of nitric acid are exploited for a number of specialty applications, such as etching of metals to reveal the microstructure.

Concentrated nitric acid is required for many chemical processes. It is produced by feeding the aqueous nitric acid resulting from the oxidation of ammonia (composition about 65% HNO3 by mass), into a concentration unit along with 60 - 67% by mass of concentrated sulphuric acid, H2SO4.

P&R Labpak can supply a wide range of Nitric Acids of different grades and quantities.

For more information on Nitric Acid:-

http://en.wikipedia.org/wiki/Nitric_acid
http://www.greener-industry.org.uk/
http://www.prlabs.co.uk/search.php