Saturday, 27 January 2018

EBOLA: PAPER TEST DIAGNOSIS UNVEILED

To combat deadly outbreaks of Ebola, researchers need a variety of simple, portable tests that help them control and treat infections. Now researchers have developed a paper-based strip that detects immunity against this viral infection. The new test uses a color-changing paper strip similar to store-bought pregnancy kits and is read using a smartphone.
Traditional lab tests for detecting the Ebola virus require advanced facilities and take days to give results. Scientists have recently developed strip-based tests that directly detect the Ebola virus by spotting the antigens it produces. But right now, doctors don’t have access to a fast, field-based test for detecting the antibodies that humans produce to fight those antigens. “Understanding a survivor’s immune response to the disease could be really useful in understanding the spread of the disease and in helping with future management,” says Molly M. Stevens, a professor of biomedical materials & regenerative medicine at Imperial College London.
Stevens and her colleagues made their new test using commercially available paper test strips. They engineered three antigens produced by different subtypes of the Ebola virus and printed lines of the protein solutions on one end of the strips. To perform the test, a few microliters of blood serum are loaded on the other end of the strip, followed by a solution of selective antibodies that will bind to the target Ebola antibodies and label them with 40-nm-wide gold nanoparticles.
The serum and the antibody solution wick along a thin channel towards the protein test lines. Ebola antibodies in the serum sample bind to the gold nanoparticles and then to the lines of proteins. The nanoparticles aggregate and reflect light, turning the test lines reddish-purple within 15 minutes.
A smartphone app developed by the team measures the intensity of the line colors from a photograph of the test strip. An intensity above a preset threshold—determined using serum from non-infected volunteers—indicates positive for Ebola antibodies. The app also allows clinicians to add patient details and geographical location to help create a map to observe disease location and spread.
The team validated the method using serum samples from 121 people in Uganda: 90 Ebola survivors and 31 non-infected local residents. Compared with results from standard lab-based enzyme-linked immunosorbent assay (ELISA), the test was 100% accurate at detecting individuals who had survived Ebola, and gave one false positive with an uninfected sample. The test strips worked with both fresh and thawed serum samples and after being stored for 16 weeks in low humidity at room temperature. The team is now working on a whole-blood test that wouldn’t require isolating the serum to make it even easier to use in remote areas.
Medical workers in rural clinics could use the new test to identify an Ebola patient’s immune response to the disease. “Understanding who is more likely and less likely to survive could help to decide on the best treatment and care,” Stevens says. It could, for instance, help determine how best to allocate limited resources.
What’s more, the system offers a way for researchers to help control the spread of the disease by monitoring and mapping it, and even prevent future outbreaks by developing vaccines. “If an Ebola vaccine were developed, the test would also be useful for identifying individuals who would not need immunization,” says Lee Gehrke, a professor of microbiology & immunology at Massachusetts Institute of Technology, who was not involved in the work.
The researchers still need to validate the test with a larger population of survivors located across a broader area, says Kimberly Hamad-Schifferli, professor of mechanical & biological engineering at MIT, who also was not involved in the study. “Other regions may have new forms of the virus that are slightly different.”

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Thursday, 25 January 2018

FERTILIZER SUBSIDY: LOW PRESSURE AMMONIA PRODUCTION

Lanthanum–cobalt catalyst that breaks nitrogen triple bond under mild conditions could revolutionise small-scale ammonia synthesis
Structural properties of LaCoSi. a Lattice structure of LaCoSi
Structure of the lanthanum–cobalt–silicon catalyst

Rather than relying on ammonia made by the energy-hungry Haber–Bosch process, local fertiliser synthesis could soon be possible with a catalyst that can break the nitrogen–nitrogen triple bond at ambient pressure.
Ammonia, one of the key ingredients in fertilisers, is made on a huge scale by the only reaction that can reliably break the strong dinitrogen bond: the Haber–Bosch process. However, the reaction needs extreme conditions – pressures of around 20MPa and temperatures of at least 400°C – which requires specialised equipment and a lot of energy. Currently, the Haber–Bosch process makes around 140 million tonnes of ammonia per year, consuming around 2% of the world’s energy output in the process.
However, a discovery made by a team led by Hideo Hosono and Junjie Wang from the Tokyo Institute of Technology, Japan, could one day cut down on those sizeable energy requirements: a lanthanum–cobalt–silicon (LaCoSi) catalyst that can break the nitrogen–nitrogen bond at ambient pressure. At 400°C, the catalyst is 10 times more efficient at making ammonia under the same conditions as its closest competitor, a cobalt–molybdenum nitride. The only other catalyst that comes close to LaCoSi’s performance contains the rare and expensive metal ruthenium.
LaCoSi is one of a family of intermetallic compounds that contains a rare earth, a transition metal and a p-block element. In this setup, cobalt is very electron-rich, which allows it to break stable bonds such as the H2 or the N2 bond. This means the rate-determining step isn’t the sluggish and energy-intensive nitrogen dissociation.
‘The activation energy of ammonia synthesis was the lowest among many reports so far,’ says Hosono. LaCoSi’s secret is a curious ‘hot atom’ mechanism: the energy released during adsorption of nitrogen on the catalyst’s surface helps break the triple bond.
‘Comparatively, the catalyst reported in this work may not be as efficient as the iron- and ruthenium-based catalysts used in industry, albeit it outperforms some of the cobalt-based catalysts,’ says Ping Chen, an expert in low-temperature ammonia synthesis at the Chinese Academy of Sciences. ‘I’m anxious to see if there are any real showstoppers, either with regards to synthesis or scale-up or compatibility with current systems,’ adds University of Michigan, US, chemical engineer Levi Thompson.
Nevertheless, Thompson calls Hosono and Wang’s work ‘pretty exciting’. ‘Tackling low temperature ammonia synthesis is one of those holy grails of chemistry,’ he says. The Tokyo scientists are now working on larger scale experiments, for which they need to improve the catalyst’s surface area.
‘It’s a very interesting piece of work in a very important area that is becoming increasingly topical,’ agrees Justin Hargreaves, catalytic materials researcher at the University of Glasgow, UK. ‘With the increasing availability of renewable sources of hydrogen, there is a desire to generate ammonia on more localised scales, for example for local fertiliser production or for energy storage,’ he adds. ‘I think [this study] will stimulate more activity.’

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Monday, 15 January 2018

QUITING CIGARETTE: Enzyme removes nicotine from blood

Image result for nicotine
NICOTINE

Scientists in the US have engineered an enzyme that halts nicotine’s psychoactive effects by breaking it down in the blood, before it can reach the brain. The enzyme could be developed into a nicotine dependence treatment that smokers could take to help them stop smoking. 
Quitting smoking is hard. A US government report from 2011 found almost 70% of American smokers want to quit and over half of smokers have tried to quit but fewer than 6% succeeded. Current cessation treatments and prescription medicines to help people stop smoking have varying success rates. Clinical trials of vaccines that encourage the body to develop nicotine antibodies to prevent it from crossing the blood–brain barrier failed to increase abstinence rates compared to a placebo.
An alternative to blocking nicotine is breaking it down. Back in 2015, K D Janda and colleagues at the Scripps Research Institute reported that the microorganism Pseudomonas putida has an enzyme, NicA2, which catalyses the oxidation of nicotine to N-methylmyosmine. In vivo tests with the enzyme had promising results but on moving to in vitro tests it became apparent the kidneys would filter out NicA2, rendering any treatment with the free enzyme short-lived.
Now, Janda and his team have stabilised NicA2. Crystal data showed that the first 52 amino acids of NicA2 are uninvolved in its activity so the team removed 50 of those and fused the rest of the enzyme to an albumin-binding domain. Associating NicA2 with albumin – the most abundant protein in plasma – increased its half-life in the body.
The team tested their new treatment on nicotine-addicted rats. After 24–48 hours of abstinence, the rats treated with the modified enzyme were less irritable and experienced fewer withdrawal symptoms, such as tremors and teeth chattering, than those who had not. The enzyme also completely eliminated nicotine from the rat’s blood and broke it down into harmless non-psychoactive products.
‘Helping smokers quit by depriving them of the nicotine kick through a nicotine degrading enzyme circulating in the body is certainly an interesting approach’ says Per-Åke Nygren, an expert in protein biotechnology at the KTH Royal Institute of Technology in Sweden. ‘However, the anti-drug immunological response from repeated delivery of a nicotine degrading enzyme of bacterial origin needs to be assessed. There is a risk that patients might develop neutralising antibodies, or that other adverse effects arise.’
Janda says this proof of concept provides a glimpse that biological products may have a role in treating substance use disorders. He adds ‘we will optimise the system to enhance further stability in vivo and remove potential parts that could cause an immune response.’

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BENZONITRILE identified in interstellar space


Image result for BENZONITRILE

The aromatic molecule benzonitrile has been detected in the Taurus Molecular Cloud – a region of interstellar space known for containing complex molecules – using radio telescopes.
Aromatic molecules are thought to be widely distributed throughout the universe, responsible for as-yet unidentified infrared bands – emissions generated by numerous cosmic sources. This, however, is the first time a specific aromatic molecule has been detected using radio spectroscopy.
Scientists at the National Radio Astronomy Observatory in Charlottesville, Virginia, used a method called spectral stacking to hunt through existing radio emissions data – gathered by the Nobeyama radio telescope in Japan – for a number of simple aromatic molecules, including benzonitrile. They were able to confirm the molecule’s identity using their own experimental data measuring the different rotational transitions of benzonitrile, combined with more observations from the Green Bank Telescope in West Virginia, which detected nine different rotational transitions of benzonitrile in the same region.
Their findings offer insights into the formation of more complex organic molecules in this part of space, where material will eventually be incorporated into new stars and planets.

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