Five more cases linked to Koyambedu market detected

A 23-year-old man who returned from Abu Dhabi on a repatriation flight, has tested positive for SARS-CoV-2. The district now has two positive recorded

The teacher was posted at a primary school in Wazirabad under the North Delhi Municipal Corporation.

Two women, who tested positive for Covid-19 and residents of the containment zone in Padarayanapura, Bengaluru, gave birth to three babies on Saturday morning. A 20-year-old woman delivered twin babies at the Trauma Care Centre. On Friday, a 34-year-old woman gave birth to a girl. Both women underwent C-sections.

‘Earlier, he tested negative thrice’

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BSB-Signatur Clm 18565

URN: urn:nbn:de:bvb:12-bsb00131315-7
URL: http://daten.digitale-sammlungen.de/~db/0013/bsb00131315/images/

Compact X-ray sources based on inverse Compton scattering provide brilliant and partially coherent X-rays in a laboratory environment. The cross section for inverse Compton scattering is very small, requiring high-power laser systems as well as small laser and electron beam sizes at the interaction point to generate sufficient flux. Therefore, these systems are very sensitive to distortions which change the overlap between the two beams. In order to monitor X-ray source position, size and flux in parallel to experiments, the beam-position monitor proposed here comprises a small knife edge whose image is acquired with an X-ray camera specifically designed to intercept only a very small fraction of the X-ray beam. Based on the source position drift recorded with the monitor, a closed-loop feedback stabilizes the X-ray source position by adjusting the laser beam trajectory. A decrease of long-term source position drifts by more than one order of magnitude is demonstrated with this device. Consequently, such a closed-loop feedback system which enables stabilization of source position drifts and flux of inverse Compton sources in parallel to experiments has a significant impact on the performance of these sources.

Melting of the semicrystalline structure of native tapioca starch granules is correlated to solution viscosity for elucidating gelatinization and gelation processes.

Sample preparation within single-particle cryo-electron microscopy can still be a significant bottleneck, with issues in reproducibility, ice quality and sample loss. New approaches have recently been reported that use spraying or pin printing instead of the traditional blotting approach. Here, experience in the use of different nozzle designs and spraying regimes is reported together with their influence on the resulting spray and grid quality.

The title compound, C13H24O9·H2O, a structural model for part of bacterial O-anti­gen polysaccharides from Shigella flexneri and Escherichia coli, crystallizes with four independent disaccharide mol­ecules and four water mol­ecules in the asymmetric unit. The conformation at the glycosidic linkage joining the two rhamnosyl residues is described by the torsion angles φH of 39, 30, 37 and 37°, and ψH of −32, −35, −31 and −32°, which are the major conformation region known to be populated in an aqueous solution. The hexo­pyran­ose rings have the 1C4 chair conformation. In the crystal, the disaccharide and water mol­ecules are associated through O—H⋯O hydrogen bonds, forming a layer parallel to the bc plane. The layers stack along the a axis via hydro­phobic inter­actions between the methyl groups.

In the title compound, C27H30N4O6·H2O, the two dioxolo rings are in envelope conformations, while the pyran ring is in a twisted-boat conformation. The pyradizine ring is oriented at dihedral angles of 9.23 (6) and 12.98 (9)° with respect to the pyridine rings, while the dihedral angle between the two pyridine rings is 13.45 (10)°. In the crystal, O—Hwater⋯Opyran, O—Hwater⋯Ometh­oxy­meth­yl and O—Hwater⋯Npyridazine hydrogen bonds link the mol­ecules into chains along [010]. In addition, weak C—Hdioxolo⋯Odioxolo hydrogen bonds and a weak C—Hmeth­oxy­meth­yl⋯π inter­action complete the three-dimensional structure. The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H⋯H (55.7%), H⋯C/C⋯H (14.6%), H⋯O/O⋯H (14.5%) and H⋯N/N⋯H (9.6%) inter­actions. Hydrogen-bonding and van der Waals inter­actions are the dominant inter­actions in the crystal packing. Electrochemical measurements are also reported.

The title compound, C24H18FNO3, crystallizes in the monoclinic centrosymmetric space group P21/n and its mol­ecular conformation is stabilized via C—H⋯O intra­molecular inter­actions. The supra­molecular network mainly comprises C—H⋯O, C—H⋯F and C—H⋯π inter­actions, which contribute towards the formation of the crystal structure. The different inter­molecular inter­actions have been further analysed via Hirshfeld surface analysis and fingerprint plots.

The X-chromosome-linked inhibitor of apoptosis protein (XIAP) is a multidomain protein whose main function is to block apoptosis by caspase inhibition. XIAP is also involved in other signalling pathways, including NF-κB activation and copper homeostasis. XIAP is overexpressed in tumours, potentiating cell survival and resistance to chemotherapeutics, and has therefore become an important target for the treatment of malignancy. Despite the fact that the structure of each single domain is known, the conformation of the full-length protein has never been determined. Here, the first structural model of the full-length XIAP dimer, determined by an integrated approach using nuclear magnetic resonance, small-angle X-ray scattering and electron paramagnetic resonance data, is presented. It is shown that XIAP adopts a compact and relatively rigid conformation, implying that the spatial arrangement of its domains must be taken into account when studying the interactions with its physiological partners and in developing effective inhibitors.

The disposition of functional groups can induce variations in the nature and type of interactions and hence affect the molecular recognition and self-assembly mechanism in cocrystals. To better understand the formation of cocrystals on a molecular level, the effects of disposition of functional groups on the formation of cocrystals were systematically and comprehensively investigated using cresol isomers (o-, m-, p-cresol) as model compounds. Consistency and variability in these cocrystals containing positional isomers were found and analyzed. The structures, molecular recognition and self-assembly mechanism of supramolecular synthons in solution and in their corresponding cocrystals were verified by a combined experimental and theoretical calculation approach. It was found that the heterosynthons (heterotrimer or heterodimer) combined with O—H⋯N hydrogen bonding played a significant role. Hirshfeld surface analysis and computed interaction energy values were used to determine the hierarchical ordering of the weak interactions. The quantitative analyses of charge transfers and molecular electrostatic potential were also applied to reveal and verify the reasons for consistency and variability. Finally, the molecular recognition, self-assembly and evolution process of the supramolecular synthons in solution were investigated. The results confirm that the supramolecular synthon structures formed initially in solution would be carried over to the final cocrystals, and the supramolecular synthon structures are the precursors of cocrystals and the information memory of the cocrystallization process, which is evidence for classical nucleation theory.

Despite the great strides made in the field of single-particle cryogenic electron microscopy (cryo-EM) in microscope design, direct electron detectors and new processing suites, the area of sample preparation is still far from ideal. Traditionally, sample preparation involves blotting, which has been used to achieve high resolution, particularly for well behaved samples such as apoferritin. However, this approach is flawed since the blotting process can have adverse effects on some proteins and protein complexes, and the long blot time increases exposure to the damaging air–water interface. To overcome these problems, new blotless approaches have been designed for the direct deposition of the sample on the grid. Here, different methods of producing droplets for sample deposition are compared. Using gas dynamic virtual nozzles, small and high-velocity droplets were deposited on cryo-EM grids, which spread sufficiently for high-resolution cryo-EM imaging. For those wishing to pursue a similar approach, an overview is given of the current use of spray technology for cryo-EM grid preparation and areas for enhancement are pointed out. It is further shown how the broad aspects of sprayer design and operation conditions can be utilized to improve grid quality reproducibly.

This study relates to the INFN project SYRMA-3D for in vivo phase-contrast breast computed tomography using the SYRMEP synchrotron radiation beamline at the ELETTRA facility in Trieste, Italy. This peculiar imaging technique uses a novel dosimetric approach with respect to the standard clinical procedure. In this study, optimization of the acquisition procedure was evaluated in terms of dose delivered to the breast. An offline dose monitoring method was also investigated using radiochromic film dosimetry. Various irradiation geometries have been investigated for scanning the prone patient's pendant breast, simulated by a 14 cm-diameter polymethylmethacrylate cylindrical phantom containing pieces of calibrated radiochromic film type XR-QA2. Films were inserted mid-plane in the phantom, as well as wrapped around its external surface, and irradiated at 38 keV, with an air kerma value that would produce an estimated mean glandular dose of 5 mGy for a 14 cm-diameter 50% glandular breast. Axial scans were performed over a full rotation or over 180°. The results point out that a scheme adopting a stepped rotation irradiation represents the best geometry to optimize the dose distribution to the breast. The feasibility of using a piece of calibrated radiochromic film wrapped around a suitable holder around the breast to monitor the scan dose offline is demonstrated.

A sample-injection device has been developed at SPring-8 Angstrom Compact Free-Electron Laser (SACLA) for serial femtosecond crystallography (SFX) at atmospheric pressure. Microcrystals embedded in a highly viscous carrier are stably delivered from a capillary nozzle with the aid of a coaxial gas flow and a suction device. The cartridge-type sample reservoir is easily replaceable and facilitates sample reloading or exchange. The reservoir is positioned in a cooling jacket with a temperature-regulated water flow, which is useful to prevent drastic changes in the sample temperature during data collection. This work demonstrates that the injector successfully worked in SFX of the human A2A adenosine receptor complexed with an antagonist, ZM241385, in lipidic cubic phase and for hen egg-white lysozyme microcrystals in a grease carrier. The injection device has also been applied to many kinds of proteins, not only for static structural analyses but also for dynamics studies using pump–probe techniques.

An error in the article by Gao, Zhang, Zhu, Wu, Mo, Pan, Liu & Jiang [J. Appl. Cryst. (2019), 52, 637–642] is corrected.

An X-ray cross-correlation study of the impact of ligand composition and salt content on the self-assembly of soft-shell nanoparticles is presented, indicating symmetry-selective formation of order.

The crystal structure of the mineral malayaite has been studied by single-crystal X-ray diffraction at a temperature of 20 K and by calculation of its phonon dispersion using density functional perturbation theory. The X-ray diffraction data show first-order satellite diffraction maxima at positions q = 0.2606 (8)b*, that are absent at room temperature. The computed phonon dispersion indicates unstable modes associated with dynamic displacements of the Ca atoms. The largest-frequency modulus of these phonon instabilities is located close to a wavevector of q = 0.3b*. These results indicate that the malayaite crystal structure is incommensurately modulated by static displacement of the Ca atoms at low temperatures, caused by the softening of an optic phonon with Bg symmetry.

The crystal structure of malayaite, CaSnOSiO4, at T = 20 K has been refined, based on the presence of satellite reflections with a modulation vector of 0.26b*. The structural modulation is attributed to a soft optic phonon, dominated by motion of the Ca atoms.

The true identity of the protein found in the crystals reported by Bondoc et al. [(2019), Acta Cryst. F75, 646–651] is given.

Unless action is taken now, coral reefs and many of the animals that depend on them may cease to exist within the next 40 years, causing the first global extinction of a worldwide ecosystem during current history.

The post Scientists establish first frozen repository of Hawaiian coral appeared first on Smithsonian Insider.

Astronomers are piecing together the reasons for these huge energy outputs, while sorting out why our own galaxy is so modest. The two primary suspects are bursts of star formation that produce many hot young stars, and processes associated with accretion of material onto a supermassive black hole at a galaxy's nucleus.

The post Luminosity of extreme galaxy most likely driven by star formation appeared first on Smithsonian Insider.

Researchers at the Smithsonian Conservation Biology Institute and partnering organizations will build a frozen repository of Great Barrier Reef coral sperm and embryonic cells. Genetic banks composed of frozen biomaterials hold strong promise for basic and applied research and conservation of species and genetic variation.

The post Smithsonian Conservation Biology Institute to help create frozen repository of sperm and embryonic cells for Great Barrier Reef corals appeared first on Smithsonian Insider.

Researchers from the Smithsonian Conservation Biology Institute, Hawaii Institute of Marine Biology and other partnering organizations spent two weeks at the end of November collecting sperm and embryonic cells during spawning from two species of coral and have built the first frozen repository for the Great Barrier Reef.

The post Smithsonian scientists help build first frozen repository of Great Barrier Reef coral appeared first on Smithsonian Insider.

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Accumulations of drifting snow are the most plausible explanation for the presence of a number of puzzling alluvial fan deposits found inside large impact craters on Mars

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Cheeseburgers. Ice cream. French fries. These are a few of the culprits, doctors warn us, responsible for atherosclerosis, a disease commonly known as hardening of […]

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Parents normally feel the need to provide well for their kids. For humans, that number of offspring is usually in the single digits, but a […]

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Save the Rhinos! Save the Elephants! Save the humans?! It seems strange to be connecting our own fate to that of wildlife but new research […]

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