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Category: chemistry – Page 445

Interferon-α2b Treatment for COVID-19

The global pandemic of COVID-19 cases caused by infection with SARS-CoV-2 is ongoing, with no approved antiviral intervention. We describe here the effects of treatment with interferon (IFN)-α2b in a cohort of confirmed COVID-19 cases in Wuhan, China. In this uncontrolled, exploratory study, 77 adults hospitalized with confirmed COVID-19 were treated with either nebulized IFN-α2b (5 mU b.i.d.), arbidol (200 mg t.i.d.) or a combination of IFN-α2b plus arbidol. Serial SARS-CoV-2 testing along with hematological measurements, including cell counts, blood biochemistry and serum cytokine levels, and temperature and blood oxygen saturation levels, were recorded for each patient during their hospital stay. Treatment with IFN-α2b with or without arbidol significantly reduced the duration of detectable virus in the upper respiratory tract and in parallel reduced duration of elevated blood levels for the inflammatory markers IL-6 and CRP. These findings suggest that IFN-α2b should be further investigated as a therapy in COVID-19 cases.

In December 2019, an outbreak of pneumonia was reported in Wuhan, Hubei province, China, resulting from infection with a novel coronavirus (CoV), severe acute respiratory syndrome (SARS)-CoV-2. SARS-CoV-2 is a novel, enveloped betacoronavirus with phylogenetic similarity to SARS-CoV (1). Unlike the coronaviruses HCoV-229E, HCoV-OC43, HCoV-NL63, and HCoV-HKU, that are pathogenic in humans and are associated with mild clinical symptoms, SARS-CoV-2 resembles both SARS-CoV and Middle East respiratory syndrome (MERS), with the potential to cause more severe disease. A critical distinction is that CoVs that infect the upper respiratory tract tend to cause a mild disease, whereas CoVs that infect both upper and lower respiratory tracts (such as SARS-CoV-2 appears to be) may cause more severe disease. Coronavirus disease (COVID)-19, the disease caused by SARS-CoV-2, has since spread around the globe as a pandemic.

In the absence of a SARS-CoV-2-specific vaccine or an approved antiviral, a number of antivirals are currently being evaluated for their therapeutic effectiveness. Type I IFNs-α/β are broad spectrum antivirals, exhibiting both direct inhibitory effects on viral replication and supporting an immune response to clear virus infection (2). During the 2003 SARS-CoV outbreak in Toronto, Canada, treatment of hospitalized SARS patients with an IFN-α, resulted in accelerated resolution of lung abnormalities (3). Arbidol (ARB) (Umifenovir) (ethyl-6-bromo-4-[(dimethylamino)methyl]-5-hydroxy-1-methyl-2 [(phenylthio)methyl]-indole-3-carboxylate hydrochloride monohydrate), a broad spectrum direct-acting antiviral, induces IFN production and phagocyte activation. ARB displays antiviral activity against respiratory viruses, including coronaviruses (4).

A ‘frozen electric-field’ approach to simulate repetitively pulsed nanosecond plasma discharges and ignition of hydrogen–air mixtures

High-fidelity modelling of nanosecond repetitively pulsed discharges (NRPDs) is burdened by the multiple time and length scales and large chemistry mechanisms involved, which prohibit detailed analyses and parametric studies. In the present work, we propose a ‘frozen electric-field’ modelling approach to expedite the NRPD simulations without adverse effects on the solution accuracy. First, a burst of nanosecond voltage pulses is simulated self-consistently until the discharge reaches a stationary state. The calculated spatial distributions and temporal evolution of the electric field, electron density and electron energy during the last pulse are then stored in a library and the electrical characteristics of subsequent pulses are frozen at these values. This strategy allows the timestep for numerical integration to be increased by four orders of magnitude (from 10−13 to 10−9 s), thereby significantly improving the computational efficiency of the process. Reduced calculations of a burst of 50 discharge pulses show good agreement with the predictions from a complete plasma model (electrical characteristics calculated during each pulse). The error in species densities is less than 20% at the centre of the discharge volume and about 30% near the boundaries. The deviations in temperature, however, are much lower, at 5% in the entire domain. The model predictions are in excellent agreement with measured ignition delay times and temperatures in H2–air mixtures subject to dielectric barrier NRPD over a pressure range of 54–144 Torr with equivalence ratios of 0.7–1.2. The OH density increases with pressure and triggers low-temperature fuel oxidation, which leads to rapid temperature rise and ignition. The ignition delay decreases by a factor of 2, with an increase in pressure from 54 to 144 Torr. In contrast, an increase in the H2–air equivalence ratio from 0.7 to 1.2 marginally decreases the ignition delay by about 20%. This behaviour is attributed to the insensitivity of OH production rates to the variation in the equivalence ratio.

MIT Nanosensor Can Alert a Smartphone When Plants Are Stressed

Carbon nanotubes embedded in leaves detect chemical signals that are produced when a plant is damaged.

MIT engineers have developed a way to closely track how plants respond to stresses such as injury, infection, and light damage, using sensors made of carbon nanotubes. These sensors can be embedded in plant leaves, where they report on hydrogen peroxide signaling waves.

Plants use hydrogen peroxide to communicate within their leaves, sending out a distress signal that stimulates leaf cells to produce compounds that will help them repair damage or fend off predators such as insects. The new sensors can use these hydrogen peroxide signals to distinguish between different types of stress, as well as between different species of plants.

Researchers develop an artificial chloroplast

Over billions of years, microorganisms and plants evolved the remarkable process we know as photosynthesis. Photosynthesis converts sun energy into chemical energy, thus providing all life on Earth with food and oxygen. The cellular compartments housing the molecular machines, the chloroplasts, are probably the most important natural engines on earth. Many scientists consider artificially rebuilding and controlling the photosynthetic process the “Apollo project of our time.” It would mean the ability to produce clean energy—clean fuel, clean carbon compounds such as antibiotics, and other products simply from light and carbon dioxide.

But how to build a living, photosynthetic cell from scratch? Key to mimicking the processes of a living cell is to get its components to work together at the right time and place. At the Max Planck Society, this ambitious goal is pursued in an interdisciplinary multi-lab initiative, the MaxSynBio network. Now the Marburg research team led by director Tobias Erb has succeeded successfully created a platform for the automated construction of cell-sized photosynthetically active compartments, “artificial chloroplasts,” that are able to capture and convert the greenhouse gas dioxide with light.

Scientists say doing this type of exercise will make your brain more powerful

According to Li and Spitzer, running on a treadmill, or performing another sustained aerobic exercise—like dancing or kickboxing—on a regular basis might actually enhance motor skill-based learning.

When comparing the brains of mice that exercised versus those who did not, Li and Spitzer found that specific neurons switched their chemical signals (neurotransmitters), after exercising, which led to improved learning for motor skill-specific acquisition.

While physical exercise is proven to promote motor skill learning in normal individuals as well as those with neurological disorders, the mechanism of action is unclear. The study found that that one just week of voluntary wheel running enhances the acquisition of motor skills in normal adult mice. Voluntary being the keyword here.

A new, highly sensitive chemical sensor uses protein nanowires

Writing in the journal NanoResearch, a team at the University of Massachusetts Amherst reports this week that they have developed bioelectronic ammonia gas sensors that are among the most sensitive ever made.

The sensor uses electric-charge-conducting protein derived from the bacterium Geobacter to provide biomaterials for electrical devices. More than 30 years ago, senior author and microbiologist Derek Lovley discovered Geobacter in river mud. The microbes grow hair-like protein filaments that work as nanoscale “wires” to transfer charges for their nourishment and to communicate with other bacteria.

First author and doctoral student Alexander Smith, with his advisor Jun Yao and Lovley, say they designed this first sensor to measure ammonia because that gas is important to agriculture, the environment and biomedicine. For example, in humans, ammonia on the breath may signal disease, while in poultry farming, the gas must be closely monitored and controlled for bird health and comfort and to avoid feed imbalances and production losses.

Nanofiber membranes transformed into 3D scaffolds

In the movie “Transformers,” cars morph into robots, jets or a variety of machinery. A similar concept inspired a group of researchers to combine gas foaming, which is a blend of chemicals that induces gas bubbling, and 3D molding technologies to quickly transform electrospun membranes into complex 3D shapes for biomedical applications.

In Applied Physics Reviews, the group reports on its new approach that demonstrates significant improvements in speed and quality compared with other methods. The work is also the first successful demonstration of formation of 3D neural constructs with an ordered structure through differentiation of human neural progenitor/ on these transformed 3D scaffolds.

“Electrospinning is a technology to produce nanofiber membranes,” said co-author Jingwei Xie, at the University of Nebraska Medical Center. “The physics principle behind it involves applying an electrical force to overcome the surface tension of a solution to elongate a solution jet into continuous and ultrafine fibers after solvent evaporation.”

Epigenetic changes during aging and their reprogramming potential

If you are interested in age reversal, and you haven’t read Dr David Sinclair (Harvard Medical School) yet, then I’d recommend this research paper.

“Excitingly, new studies show that age-related epigenetic changes can be reversed with interventions such as cyclic expression of the Yamanaka reprogramming factors. This review presents a summary of epigenetic changes that occur in aging, highlights studies indicating that epigenetic changes may contribute to the aging process and outlines the current state of research into interventions to reprogram age-related epigenetic changes.”

The aging process results in significant epigenetic changes at all levels of chromatin and DNA organization. These include reduced global heterochromatin, nucleosome remodeling and loss, changes in histone marks, global DNA hypomethylation with CpG island hypermethylation, and the relocalization of chromatin modifying factors. Exactly how and why these changes occur is not fully understood, but evidence that these epigenetic changes affect longevity and may cause aging, is growing. Excitingly, new studies show that age-related epigenetic changes can be reversed with interventions such as cyclic expression of the Yamanaka reprogramming factors. This review presents a summary of epigenetic changes that occur in aging, highlights studies indicating that epigenetic changes may contribute to the aging process and outlines the current state of research into interventions to reprogram age-related epigenetic changes.

The term “epigenetics” is thrown around a lot. Originally, it was coined to describe heritable changes that were non-mendelian, but use of the term has evolved. These days, “epigenetics” more generally refers to all non-genomic information storage in cells including gene networks, chromatin structure and post-translational modifications to histones. With aging, there are distinct changes across the epigenome from DNA modifications to alterations in global chromatin organization. But key questions remain unanswered: How and why do these changes occur? Do these changes drive disease and aging? Are they reversible?

Genomic organization is determined by the complex structure of chromatin ( Figure 1 ). The basic unit of chromatin is the nucleosome, which is made up of 147 DNA base pairs wrapped around an octamer of histone proteins. This octamer usually comprises two copies each of H2A, H2B, H3 and H4 (Luger et al. 1997; Hansen 2002). Within nucleosomes, both histones and the DNA itself are subject to a range of chemical modifications that affect the chromatin structure and ultimately the expression of genes. Chromatin falls into one of two major subtypes: euchromatin, in which the chromatin is open and transcriptionally active and heterochromatin, in which the chromatin is tightly closed and transcriptionally silent (Wallrath 1998; Grewal and Moazed 2003). Regulating the epigenetic network are factors that modify chromatin including DNA- and histone-modifying enzymes, transcription factors, and the more recently identified noncoding RNAs (ncRNAs).

Electromagnetic water cloak eliminates drag and wake

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object’s wake, greatly reducing its drag while simultaneously helping it avoid detection.

The idea originated at Duke University in 2011 when researchers outlined the general concept. By matching the acceleration of the surrounding water to an ’s movement, it would theoretically be possible to greatly increase its propulsion efficiency while leaving the surrounding sea undisturbed. The theory was an extension of the group’s pioneering work in metamaterials, where a material’s structure, rather than its chemistry, creates desired properties.

Six years later, Yaroslav Urzhumov, adjunct assistant professor of electrical and computer engineering at Duke, has updated the theory by detailing a potential approach. But rather than using a complex system of very small pumps as originally speculated, Urzhumov is turning to electromagnetic fields and the dense concentration of charged particles found in saltwater.

Revealed: Plants Molecular ‘Alarm’ System That Protects Them From Predators

Scientists uncover how oral secretions of the cotton leaf worm trigger defense responses in a plant.

In nature, every species must be equipped with a strategy to be able to survive in response to danger. Plants, too, have innate systems that are triggered in response to a particular threat, such as insects feeding on them.

For example, some plants sense “herbivore-derived danger signals” (HDS), which are specific chemicals in oral secretions of insects. This activates a cascade of events in the plant’s defense machinery, which leads to the plant developing “resistance” to (or “immunity” against) the predator. But despite decades of research, exactly how plants recognize these signals has remained a bit of a mystery.

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