A tunable radiation source by coupling laser-plasma-generated electrons to a periodic structure

Near-infrared radiation around 1000 nm generated from the interaction of a high-density MeV electron beam, obtained by impinging an intense ultrashort laser pulse on a solid target, with a metal grating is observed experimentally. Theoretical modeling and particle-in-cell simulation suggest that the radiation is caused by the Smith-Purcell mechanism. The results here indicate that tunable terahertz radiation with tens GV=m field strength can be achieved by using appropriate grating parameter

Intraflagellar transport dynein is autoinhibited by trapping of its mechanical and track-binding elements

Cilia are multi-functional organelles that are constructed using intraflagellar transport (IFT) of cargo to and from their tip. It is widely held that the retrograde IFT motor, dynein-2, must be controlled in order to reach the ciliary tip and then unleashed to power the return journey. However, the mechanism is unknown. Here, we systematically define the mechanochemistry of human dynein-2 motors as monomers, dimers, and multi-motor assemblies with kinesin-II. Combining these data with insights from single-particle electron microscopy, we discover that dynein-2 dimers are intrinsically autoinhibited. Inhibition is mediated by trapping dynein-2’s mechanical “linker” and “stalk” domains within a novel motor-motor interface. We find that linker-mediated inhibition enables efficient transport of dynein-2 by kinesin-II in vitro. These results suggest a conserved mechanism for autoregulation among dimeric dyneins, which is exploited as a switch for dynein-2’s recycling activity during IFT

ИССЛЕДОВАНИЕ НЕЙРОРЕТИНОПРОТЕКТОРНОЙ АКТИВНОСТИ ТИОФАНА ПРИ ИНВОЛЮЦИОННОЙ ХОРИОРЕТИНАЛЬНОЙ ДЕГЕНЕРАЦИИ КРЫС ЛИНИИ OXYS

The method of spontaneous and induced luminol -dependent chemiluminescence in homogenates of rat retinas OXYS registered increase in the generation of free radicals against decrease in total antioxidant  activity.  With  the  ultra-microscopic  and  quantitative  analysis  revealed  degenerative retinal neurons rats OXYS: the percentage increase in neurosensory cells with pyknosis of nuclei, hyperchromatic piknomorfnyh associative neurons and ganglion n eurons that have been modified on a light and dark type. Thiophane, limiting free radical reactions in the retina and protects retinal neurons from damage.С помощью метода спонтанной и индуцированной люминолзависимой хемилюминесценции в гомогенатах сетчаток крыс линии OXYS зарегистрировано повышение уровня генерации свободных радикалов на фоне снижения общей антиокислительной активности. С помощью ультрамикроскопического и количественного анализа выявлены дегенеративные изменения нейронов сетчатки крыс линии OXYS: увеличение содержания нейросенсорных клеток с пикнозом ядра, гиперхромных  пикноморфных  ассоциативных нейронов и ганглионарных нейронов, измененных по светлому и темному типу. Установлено, что тиофан, ограничивая свободнорадикальные реакции в сетчатке, защищает нейроны сетчатки от повреждения

Meiotic Recombination Hotspots of Fission Yeast Are Directed to Loci that Express Non-Coding RNA

Polyadenylated, mRNA-like transcripts with no coding potential are abundant in eukaryotes, but the functions of these long non-coding RNAs (ncRNAs) are enigmatic. In meiosis, Rec12 (Spo11) catalyzes the formation of dsDNA breaks (DSBs) that initiate homologous recombination. Most meiotic recombination is positioned at hotspots, but knowledge of the mechanisms is nebulous. In the fission yeast genome DSBs are located within 194 prominent peaks separated on average by 65-kbp intervals of DNA that are largely free of DSBs.). Furthermore, we tested and rejected the hypothesis that the ncRNA loci and DSB peaks localize preferentially, but independently, to a third entity on the chromosomes.Meiotic DSB hotspots are directed to loci that express polyadenylated ncRNAs. This reveals an unexpected, possibly unitary mechanism for what directs meiotic recombination to hotspots. It also reveals a likely biological function for enigmatic ncRNAs. We propose specific mechanisms by which ncRNA molecules, or some aspect of RNA metabolism associated with ncRNA loci, help to position recombination protein complexes at DSB hotspots within chromosomes

Response of the primary auditory and non-auditory cortices to acoustic stimulation: A manganese-enhanced MRI study

Structural and functional features of various cerebral cortices have been extensively explored in neuroscience research. We used manganese-enhanced MRI, a non-invasive method for examining stimulus-dependent activity in the whole brain, to investigate the activity in the layers of primary cortices and sensory, such as auditory and olfactory, pathways under acoustic stimulation. Male Sprague-Dawley rats, either with or without exposure to auditory stimulation, were scanned before and 24-29 hour after systemic MnCl2 injection. Cortex linearization and layer-dependent signal extraction were subsequently performed for detecting layer-specific cortical activity. We found stimulus-dependent activity in the deep layers of the primary auditory cortex and the auditory pathways. The primary sensory and visual cortices also showed the enhanced activity, whereas the olfactory pathways did not. Further, we performed correlation analysis of the signal intensity ratios among different layers of each cortex, and compared the strength of correlations between with and without the auditory stimulation. In the primary auditory cortex, the correlation strength between left and right hemisphere showed a slight but not significant increase with the acoustic simulation, whereas, in the primary sensory and visual cortex, the correlation coefficients were significantly smaller. These results suggest the possibility that even though the primary auditory, sensory, and visual cortices showed enhanced activity to the auditory stimulation, these cortices had different associations for auditory processing in the brain network.open0

School closures during the 2009 influenza pandemic: national and local experiences

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