Journal of Physics: Conference Series | Year: 2013
We report the first measurements of azimuthal anisotropy at midrapidity originated from the dipole asymmetry due to uctuations in the initial geometry in Au+Au collisions at √sNN = 200 GeV, based on data from the STAR experiment at the Relativistic Heavy Ion Collider. The signal is almost symmetric in pseudorapidity and we report it as a function of pseudorapidity and transverse momentum for different centrality. Results are compared with available model predictions.
Journal of Physics: Conference Series | Year: 2015
We report the measurement of the directed flow (v1) for charged kaons in Au+Au collisions at √sNN=7.7, 11.5, 19.6, 27, 39, 62.4 and 200 GeV as a function of rapidity and compare these results for pions, protons and antiprotons. These new kaon results may help to constrain the medium properties and collision dynamics including the in-medium kaon potential and baryon number transport in these collisions. © Published under licence by IOP Publishing Ltd.
Bacteria possess the ability to take up DNA from their environment, a skill that enables them to acquire new genes for antibiotic resistance or to escape the immune response. Scientists have now mapped the core set of genes that are consistently controlled during DNA uptake in strep bacteria, and they hope the finding will allow them to cut off the microbes' ability to survive what doctors and nature can throw at them. The findings, by a team of researchers from the University of Oslo, the Forsyth Institute, and the University of Illinois at Chicago, appeared last week in the American Society for Microbiology's new open-access journal, mSystems. The researchers wanted to know precisely which metabolic pathways in the bacterial cell must be activated for the bacteria to become "competent," or able to acquire genes from DNA in the environment. They focused on Streptococcus mutans, a strain involved in tooth decay. Earlier studies of competence had pointed to more than 300 active genes. The new study identifies only 83 genes in 29 regions of the strep chromosome that are specific to the competence pathway, with 27 of these genes lying within an interconnected network controlled by one of three key regulator molecules. When the researchers compared the new results to earlier studies in five other strep species, they found that in all those species a core set of only 27 activated competence genes was required for DNA uptake. "Streptococcus is a diverse group of species that evolved from a common ancestor to adapt to diverse hosts and sugar-rich niches," says study co-author Donald Morrison, professor of biological sciences at UIC. "Our findings—that two-thirds of the core activated genes in streptococcus have transformation functions—suggest that this is an ancient response, maintained because of its value in promoting ready access to external DNA." The question now, says Morrison, is what is the function of the remaining one-third of the core genes? "We know that gene transfer can occur in their absence," the authors write, "suggesting that new aspects of competence are just waiting to be discovered." New insights in this field may pave the way to new strategies to avoid unwanted gene transfers, such as those enabling the spread of antibiotic resistance.
Abstract: An effective vaccine against the virus that causes genital herpes has evaded researchers for decades. But now, researchers from the University of Illinois at Chicago working with scientists from Germany have shown that zinc-oxide nanoparticles shaped like jacks can prevent the virus from entering cells, and help natural immunity to develop. Results of the study are published in The Journal of Immunology. "We call the virus-trapping nanoparticle a microbivac, because it possesses both microbicidal and vaccine-like properties," says corresponding author Deepak Shukla, professor of ophthalmology and microbiology & immunology in the UIC College of Medicine. "It is a totally novel approach to developing a vaccine against herpes, and it could potentially also work for HIV and other viruses," he said. The particles could serve as a powerful active ingredient in a topically-applied vaginal cream that provides immediate protection against herpes virus infection while simultaneously helping stimulate immunity to the virus for long-term protection, explained Shukla. Herpes simplex virus-2, which causes serious eye infections in newborns and immunocompromised patients as well as genital herpes, is one of the most common human viruses. According to the Centers for Disease Control and Prevention, about 15 percent of people from ages 14-49 carry HSV-2, which can hide out for long periods of time in the nervous system. The genital lesions caused by the virus increase the risk for acquiring human immunodeficiency virus, or HIV. "Your chances of getting HIV are three to four times higher if you already have genital herpes, which is a very strong motivation for developing new ways of preventing herpes infection," Shukla said. Treatments for HSV-2 include daily topical medications to suppress the virus and shorten the duration of outbreaks, when the virus is active and genital lesions are present. However, drug resistance is common, and little protection is provided against further infections. Efforts to develop a vaccine have been unsuccessful because the virus does not spend much time in the bloodstream, where most traditional vaccines do their work. The tetrapod-shaped zinc-oxide nanoparticles, called ZOTEN, have negatively charged surfaces that attract the HSV-2 virus, which has positively charged proteins on its outer envelope. ZOTEN nanoparticles were synthesized using technology developed by material scientists at Germany's Kiel University and protected under a joint patent with UIC. When bound to the nanoparticles, HSV-2 cannot infect cells. But the bound virus remains susceptible to processing by immune cells called dendritic cells that patrol the vaginal lining. The dendritic cells "present" the virus to other immune cells that produce antibodies. The antibodies cripple the virus and trigger the production of customized killer cells that identify infected cells and destroy them before the virus can take over and spread. The researchers showed that female mice swabbed with HSV-2 and an ointment containing ZOTEN had significantly fewer genital lesions than mice treated with a cream lacking ZOTEN. Mice treated with ZOTEN also had less inflammation in the central nervous system, where the virus can hide out. The researchers were able to watch immune cells pry the virus off the nanoparticles for immune processing, using high-resolution fluorescence microscopy. "It's very clear that ZOTEN facilitates the development of immunity by holding the virus and letting the dendritic cells get to it," Shukla said. If found safe and effective in humans, a ZOTEN-containing cream ideally would be applied vaginally just prior to intercourse, Shukla said. But if a woman who had been using it regularly missed an application, he said, she may have already developed some immunity and still have some protection. Shukla hopes to further develop the nanoparticles to work against HIV, which like HSV-2 also has positively charged proteins embedded in its outer envelope. ZOTEN particles are uniform in size and shape, making them attractive for use in other biomedical applications. The novel flame transport synthesis technology used to make them allows large-scale production, said Rainer Adelung, professor of nanomaterials at Kiel University. And, because no chemicals are used, the production process is green. Adelung hopes to begin commercial production of ZOTEN through a startup company that will be run jointly with his colleagues at UIC. ### Co-authors on the study are Bellur Prabhakar, Tibor Valyi-Nagy, Thessicar Antoine, Satvik Hadigal, Abraam Yakoub, Palash Bhattacharya, and Christine Haddad of UIC and Yogendra Kumar Mishra of Kiel University. The research was supported by National Institutes of Health grants AI103754 and EY001792 and German Research Foundation grant Ad/183/10-1. For more information, please click If you have a comment, please us. Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.
News Article | August 22, 2016
CleanTechnica spills a lot of ink on solar cell efficiency, but there is another important angle to the solar revolution that doesn’t get quite as much attention. That’s the “artificial leaf” concept, in which solar energy touches off a chemical reaction that produces a usable fuel. If that starts ringing some bells, you’re probably thinking about that time you learned about the natural process of photosynthesis in high school. In the latest development, researchers at the University of Illinois at Chicago have tweaked Mother Nature to capture and recycle atmospheric carbon dioxide, with an assist from researchers at Argonne National Laboratory, the University of New Mexico and the University of Illinois at Urbana-Champaign. The last couple of times CleanTechnica covered the artificial leaf concept, the end goal was to use solar energy for splitting water, arriving at hydrogen as the end product. Essentially, it’s a hydrogen-based energy storage system. It’s worth pausing to note that one of the original pioneers of the artificial leaf concept, Daniel Nocera, has also been making waves in energy storage. The flow battery work of his startup Sun Catalytix caught the attention of Lockheed Martin back in 2012. Lockheed eventually acquired the company in 2014 and renamed the operation “Lockheed Martin Advanced Energy Storage, LLC.” Meanwhile, artificial leaf research has been progressing on other fronts. Last year, for example, a team at Harvard came up with a “bionic leaf” system that produces rubbing alcohol. The new UIC/Argonne iteration takes it up to the next level. The new system produces a mix of carbon and hydrogen that could be used directly as synthetic gas, which doesn’t seem like that big of a deal except when you consider the atmospheric carbon capture angle. Once you have syngas, you can also get to diesel, gasoline and other liquid fuels. Here’s how the UIC team articulates it: The ability to turn CO2 into fuel at a cost comparable to a gallon of gasoline would render fossil fuels obsolete. The Argonne team is particularly excited about tackling the carbon monoxide conversion part of the process, because in CO2 form carbon is difficult to recombine with for anything else. That’s the sticky wicket in a nutshell — finding an efficient, commercially viable way to convert CO2 to CO. Plants and other organisms can hack CO2 into CO without batting an eyelash, but replicating that process in the lab during one human lifetime is quite a tall order. The basic idea behind the new artificial leaf is an economical one-pot system that encompasses the entire three-step process. The first two steps sound a lot like conventional artificial leaf business. Step one is the energy harvesting part, in which photons are converted into pairs of electrons (negative charges) and “holes” (positive charges). Step two is the reaction between holes and water molecules. That results in the creation of protons and oxygen molecules. Step three is where the magic happens: Finally, the protons, electrons and carbon dioxide all react together to create carbon monoxide and water. To flesh out that third step, you can read all about the new system in the journal Science under the title “Nanostructured transition metal dichalcogenide electrocatalysts for CO2 reduction in ionic liquid.” For those of you on the go, the short version is that the research team was challenged to come up with a durable, economical catalyst to accomplish the reaction in Step 3. They finally settled on using nanoscale flakes of the transition metal WSe2 (tungsten diselenide). In addition, the team found that adding an ionic (“salty”) liquid to water further enhanced the efficiency. Here’s the rundown from UIC: The UIC artificial leaf consists of two silicon triple-junction photovoltaic cells of 18 square centimeters to harvest light; the tungsten diselenide and ionic liquid co-catalyst system on the cathode side; and cobalt oxide in potassium phosphate electrolyte on the anode side. When light of 100 watts per square meter – about the average intensity reaching the Earth’s surface – energizes the cell, hydrogen and carbon monoxide gas bubble up from the cathode, while free oxygen and hydrogen ions are produced at the anode. As for commercialization, if that doesn’t work out on Earth then there’s always Mars, which has atmospherice CO2 in abundance. Photo (cropped): “Simulated sunlight powers a solar cell that converts atmospheric carbon dioxide directly into syngas” via UIC. Drive an electric car? Complete one of our short surveys for our next electric car report. Keep up to date with all the hottest cleantech news by subscribing to our (free) cleantech newsletter, or keep an eye on sector-specific news by getting our (also free) solar energy newsletter, electric vehicle newsletter, or wind energy newsletter.