Researchers get new view of how water and sulfur dioxide mix

High in the sky, water in clouds can act as a temptress to lure airborne pollutants such as sulfur dioxide into reactive aqueous particulates. Although this behavior is not incorporated into today's climate-modeling scenarios, emerging research from the University of Oregon provides evidence that it should be.

The role of sulfur dioxide -- a pollutant of volcanic gasses and many combustion processes -- in acid rain is well known, but how sulfur dioxide reacts at the surface of aqueous particulates in the atmosphere to form acid rain is far from understood.

In National Science Foundation-funded laboratory experiments at the UO, chemistry doctoral student Stephanie T. Ota examined the behavior of sulfur dioxide as it approaches and adsorbs onto water at low temperatures that mimic high-atmospheric conditions. Using a combination of short-pulsed infrared and visible laser beams, she monitored the interaction of sulfur dioxide with water as it is flowed over a water surface.

The results -- detailed online ahead of regular publication in the Journal of the American Chemical Society -- show that as sulfur dioxide molecules approach the surface of water, they are captured by the top-most surface water molecules, an effect that is enhanced at cold temperatures.

Although this reaching out, says co-author Geraldine L. Richmond, professor of chemistry, provides a doorway for sulfur dioxide to enter the water solution, the weak nature of the surface-bonding interaction doesn't guarantee that the water temptress will be successful.

"We have found that that the sulfur dioxide bonding to the surface is highly reversible and does not necessarily provide the open doorway that might be expected," Ota said. "For example, for highly acidic water, the sulfur dioxide approaches and bonds to the water surface but shows little interest in going any further into the bulk water."

The uptake of gases like sulfur dioxide has important implications in understanding airborne pollutants and their role in global warming and climate change. Sulfur dioxide that has come together with water, becoming aqueous, reflects light coming toward the planet, while carbon dioxide accumulating in the atmosphere traps heat onto the planet.

Understanding the interaction of surface water molecules, such as those in clouds and fog, with pollutants rising from human activity below may help scientists better predict potential chemical reactions occurring in the atmosphere and their impacts, said Richmond, who was elected May 3 as a member of the National Academy of Sciences.

"In the past we presumed that most chemistry in the atmosphere occurred when gas molecules collide and react," she said. "These studies are some of the first to provide molecular insights into what happens when an atmospherically important gas such as sulfur dioxide collides with a water surface, and the role that water plays in playing the temptress to foster reactivity."

Provided by University of Oregon (news : web)

New chemistry technology promises more effective prescription drug therapies

Scientists at the University of Toronto and Stanford and Columbia Universities have developed a way to measure the action and function of candidate prescription drugs on human cells, including the response of individual cells, more quickly and on a larger scale than ever before.

The researchers say their mass cytometry technology has the potential to transform the understanding of a variety of diseases and biologic actions and will provide a better tool to understand how a healthy cell becomes diseased. Clarifying the underlying biochemistry of cells may enable earlier detection of illness and ultimately advance personalized medicine, notably for cancer and HIV treatments, by offering more and less aggressive options for treatment.

“We’ve shown that drug response is specific to certain sub-populations of cells and gained insight into the signalling cascade that defines that response” said Professor Scott Tanner of the Department of Chemistry, who led the development of the technology used in research to be published this week in Science. “We’ve also shown that a drug can activate or suppress multiple response pathways simultaneously, and that these responses are modified when a combination of drugs are administered.”

“Together, this suggests that the technology will be of significant value in the development and validation of rational drugs to target particular pathogens - a quantum step towards the provision of personalized medicine,” said Tanner.

Mass cytometry allows simultaneous measurement of as many as 100 biomarkers - specific physical traits of cells used to measure or indicate the effects or progress of a disease, illness or condition - in single cells, at 1,000 cells per second. It applies the analytical capabilities of atomic mass spectrometry - used to measure the number and type of atoms that comprise a sample - to the technique of flow cytometry, which is a method of examining thousands of microscopic particles per second by suspending them in a stream of fluid or gas and passing them through an electronic detection apparatus. The two very disparate disciplines previously had no reason to be combined.

The U of T scientists developed the chemistry and methods of attaching the metal atoms necessary for the detection of the vanishingly rare biomolecules of interest at the individual cell level, where personal therapeutic response is defined. They also developed a unique instrument to simultaneously measure a large number of these diagnostic signals for individual cells at a high analysis rate. Garry Nolan, a professor of microbiology and immunology at Stanford University and lead investigator of the research presented in this paper, adapted and expanded his earlier work in flow cytometry to take advantage of the much higher power that mass cytometry provides.

Nolan and his colleagues at Stanford, with collaborators at Columbia, used the U of T technology to monitor 34 different substances found inside and on the surface of different cell types produced in human bone marrow, the place where all immune and blood cells, as well as blood disorders such as leukemia, originate. They were able not only to correctly categorize over a dozen different immune cell types but, at the same time, to peer inside the cells and learn how various internal processes differed from one cell type to the next. “We can tell not only what kind of cell it is but what it’s thinking, and what it may become,” says Nolan.

The findings are presented in a paper titled 'Single-Cell Mass Cytometry of Differential Immune and Drug Responses Across a Human Hematopoietic Continuum', published May 6 in Science. The technology developed by Tanner and his associates is being brought to market by DVS Sciences Inc., a U of T spin-off of which Tanner is president and CEO.

More information: Science 6 May 2011: Vol. 332 no. 6030 pp. 687-696 DOI: 10.1126/science.1198704

ABSTRACT
Flow cytometry is an essential tool for dissecting the functional complexity of hematopoiesis. We used single-cell “mass cytometry” to examine healthy human bone marrow, measuring 34 parameters simultaneously in single cells (binding of 31 antibodies, viability, DNA content, and relative cell size). The signaling behavior of cell subsets spanning a defined hematopoietic hierarchy was monitored with 18 simultaneous markers of functional signaling states perturbed by a set of ex vivo stimuli and inhibitors. The data set allowed for an algorithmically driven assembly of related cell types defined by surface antigen expression, providing a superimposable map of cell signaling responses in combination with drug inhibition. Visualized in this manner, the analysis revealed previously unappreciated instances of both precise signaling responses that were bounded within conventionally defined cell subsets and more continuous phosphorylation responses that crossed cell population boundaries in unexpected manners yet tracked closely with cellular phenotype. Collectively, such single-cell analyses provide system-wide views of immune signaling in healthy human hematopoiesis, against which drug action and disease can be compared for mechanistic studies and pharmacologic intervention.

Provided by University of Toronto (news : web)

A new detection system can reveal bioterrorist attacks on our water supply network

 

If pathogens enter into our water supply network many people may fall ill quickly. To protect us against this biological threat, researchers have developed a detection system partly based on nanotechnology that can warn authorities in time.

In the 21st century several countries have suffered great losses after terrorist attacks. Although the risk of bioterrorist attacks or accidental contamination of our water supply network is low, the consequences could be fatal. Researchers connected to DINAMICS (DIagnostic NAnotech and MICrotech Sensors), a project co-funded by the European commission, have made a lab-on-a-chip device that can monitor our drinking water and spot different pathogens even at very low concentrations.

The device uses sensors with very small strands of different pathogenic DNA integrated onto their surfaces to quickly recognize pathogenic DNA from water samples. The DNA in the sensors will only bind to the water samples’ corresponding DNA, multiplied for easier identification. To see what different DNAs are present in the water samples, the researchers apply a reaction called chemiluminescence that will make the bound DNAs emit light. The nanoscale reactions are then interpreted by a computer. The DINAMICS project’s researchers have also developed another type of sensor that changes the bound DNAs into electric signals. The signal’s magnitude is proportional to the quantity of pathogenic DNA from the water sample.

At present, water samples are brought to the laboratory for analysis. The researchers’ goal is to make this step redundant by bringing the laboratory to the water instead, since the device is part of a portable detection system. This would speed up the process substantially. If the system detects a biological threat the authorities can be informed through email or mobile phone.

Another way of spotting accidental or deliberate water contamination has been developed by the Fraunhofer Institute in Germany. By also recognizing that existing methods for water analysis are time-consuming they have set up a system called AquaBioTox, which uses living microorganisms. A sensitive camera system continuously records and analyses the microorganisms’ reactions to the water. Even though the researchers have documented a reliable and fast detection of contaminants, to guarantee robustness against false alarm and maximum reliability in diagnosis they recommend that the system is combined with other sensors on the market.

The DINAMICS project is planned to end the last day of March and if the system becomes widely available in the water industry this more cost-efficient way of testing could significantly improve water safety, alone or in combination with other sensors.

Provided by Youris.com (news : web)

More effective and less risky when you paint the hull of your boat

Every boat owner recognises the dilemma: environmentally friendly or effective. Researchers at the University of Gothenburg have now found a way of reconciling these two almost unattainable aims. By using smart combinations of the most environmentally friendly biocides in the paint, it is possible to both reduce the total quantity of biocides and dramatically reduce the environmental impact.

"It's very easy to make an environmentally friendly hull paint, and just as easy to make an effective hull paint. Yet there is still no paint that is both effective and environmentally friendly, which leaves both environmental authorities and boat owners dissatisfied," says Hans Blanck, Professor of Ecotoxicology at the Department of Plant and Environmental Sciences of the University of Gothenburg.

Professor Blanck has directed several sub-projects in the interdisciplinary research programme Marine Paint, which is financed by Mistra. Marine Paint is Sweden's largest combined research programme in the area of marine fouling and environmentally sound hull paints. The project began in 2003 with a substance that had been found to be effective against barnacles: medetomidine. Today the researchers are developing formulas to prevent all types of fouling through what are known as optimised blends of biocides, that is to say substances that can kill or otherwise cause problems for living organisms.

"The hull paints of today often contain one or two different biocides, and they need to be highly dosed to eliminate all types of fouling organisms. The idea behind optimised blends is to base them on several complementary biocides in the paint. In this way the combinations make more efficient use of each biocide and less overdosing is needed. We get rid of all fouling and the total need for biocides in the paint is reduced dramatically as a result."

To devise formulas for optimal blends, the researchers have developed a system of models in which the effect of different biocides on different types of fouling organisms is weighed up against the expected environmental risk. The result is a set of formulas – with different concentrations and combinations of biocides – that all are equally effective in preventing fouling. What distinguishes them is the anticipated risk to the environment. The formulas can therefore be adapted effectively to different conditions. The substances that the researchers have selected, in addition to medetomidine, are biocides that are on the market today and that will probably pass the ongoing evaluation under the EU Biocidal Products Directive.

Another common problem with present-day hull paints is that the active substances leach out too quickly. Large amounts of biocides are therefore needed for the paint to be effective over a long period.

"By using what are known as microcapsules, a microscopic bubble of polymer material containing dissolved bioicides, we can control release better. This technique works for virtually any biocide."

Provided by University of Gothenburg (news : web)

Chemist investigates material for next-generation computer memory

Investigating the building blocks for next-generation computer memory has earned a University of Houston (UH) chemist his third Tier One research award.

Vassiliy Lubchenko, an assistant professor of chemistry at UH, was recently selected as a 2011 Alfred P. Sloan Research Fellow for his achievements and potential to contribute substantially to his field. Drawn from 54 colleges and universities in the United States and Canada, this year's 118 fellows are early-career scientists and scholars. Lubchenko is one of four winners in Texas. Each will receive a $50,000 fellowship in support of original research and education in science, technology, engineering, mathematics and economic performance.

As a theoretical physical chemist, Lubchenko takes raw data from researchers in a lab and uses mathematical and computer modeling to explain existing measurements and predict what will occur in future experiments and other systems. Amorphous semiconductors, for example, are something he is studying for their applications in phase-change computer memory, which is a potential successor of flash memory.

"One can control the conductivity and reflectivity of phase-change materials – and hence encode information – by varying the speed of cooling a melted material and forcing it to either crystallize or to form a glassy solid," Lubchenko said. "Glass transition is one of the most important, yet least understood, branches of modern physical chemistry. Semiconductor glasses exhibit many unique anomalies whose explanation has evaded researchers for decades. My findings show these anomalies are not a generic consequence of disorder, but instead can be traced to how these solids form from the corresponding liquid."

An important component of his research is to predict the structure and glass-forming ability of specific substances. This task is inaccessible to computer technology, but Lubchenko's technique applies a combination of analytical theories and computational modeling that singles out the most important aspects of the liquid dynamics and electronic motions that precede the glass transition and are amenable to mathematical treatment.

Another area of Lubchenko's research involves protein aggregation, a process thought to be responsible for many degenerative diseases, such as sickle cell anemia or Alzheimer's. His work may make it easier to make protein crystals, which could help in the treatment of such diseases.

"Vas' Sloan award, his third Tier One award since 2008, is recognition by his peers that he tackles and solves tough research problems," said David Hoffman, professor and chair of the chemistry department in the College of Natural Sciences and Mathematics at UH. "We are very proud of his accomplishments and feel fortunate to have him as a colleague."

Provided by University of Houston (news : web)