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Happy Mother’s Day 2020: Wishes, images, quotes, status, messages, cards, wallpapers, and photos




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Is your mother getting her essential nutrients? Check here




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This dry fruit is a healthy munching snack




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Happy Mother’s Day 2020: Wishes, images, Whatsapp messages, status, quotes and photos




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This Mother’s Day, doctors share what it’s like to help other women become mothers




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Cops seize Rs 97L, Land Rover, 2 pistols in UT

Five days after nearly 5,500 cases of liquor seized by police went missing in Sonipat, Haryana Police on Saturday raided the Chandigarh hideout of the godown owner's husband and seized Rs 97 lakh, a Range Rover car, two pistols and a three mobile phones.




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Narco-terrorist with K-group links held in Sirsa

Three people, including two brothers running a narco terrorism network linked to Hizbul Mujahideen commander Naikoo, who was killed by security forces in Kashmir recently, were on Saturday arrested in a joint operation conducted by Haryana Police, National Investigation Agency (NIA) and Punjab Police.




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Manimajra: Whisky thieves pull out Rs 13L stock

Thieves broke into a liquor vend in Manimajra and stole 204 liquor boxes worth around Rs 13 lakh on Friday.




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Chandigarh extends excise policy till June 30

The UT excise and taxation department has extended the excise policy from May 15 to June 30 due to the Covid-19 pandemic and the ongoing lockdown.




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A versatile nanoreactor for complementary in situ X-ray and electron microscopy studies in catalysis and materials science

Two in situ `nanoreactors' for high-resolution imaging of catalysts have been designed and applied at the hard X-ray nanoprobe endstation at beamline P06 of the PETRA III synchrotron radiation source. The reactors house samples supported on commercial MEMS chips, and were applied for complementary hard X-ray ptychography (23 nm spatial resolution) and transmission electron microscopy, with additional X-ray fluorescence measurements. The reactors allow pressures of 100 kPa and temperatures of up to 1573 K, offering a wide range of conditions relevant for catalysis. Ptychographic tomography was demonstrated at limited tilting angles of at least ±35° within the reactors and ±65° on the naked sample holders. Two case studies were selected to demonstrate the functionality of the reactors: (i) annealing of hierarchical nanoporous gold up to 923 K under inert He environment and (ii) acquisition of a ptychographic projection series at ±35° of a hierarchically structured macroporous zeolite sample under ambient conditions. The reactors are shown to be a flexible and modular platform for in situ studies in catalysis and materials science which may be adapted for a range of sample and experiment types, opening new characterization pathways in correlative multimodal in situ analysis of functional materials at work. The cells will presently be made available for all interested users of beamline P06 at PETRA III.




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Low-dose X-ray structure analysis of cytochrome c oxidase utilizing high-energy X-rays

To investigate the effect of high-energy X-rays on site-specific radiation-damage, low-dose diffraction data were collected from radiation-sensitive crystals of the metal enzyme cytochrome c oxidase. Data were collected at the Structural Biology I beamline (BL41XU) at SPring-8, using 30 keV X-rays and a highly sensitive pixel array detector equipped with a cadmium telluride sensor. The experimental setup of continuous sample translation using multiple crystals allowed the average diffraction weighted dose per data set to be reduced to 58 kGy, and the resulting data revealed a ligand structure featuring an identical bond length to that in the damage-free structure determined using an X-ray free-electron laser. However, precise analysis of the residual density around the ligand structure refined with the synchrotron data showed the possibility of a small level of specific damage, which might have resulted from the accumulated dose of 58 kGy per data set. Further investigation of the photon-energy dependence of specific damage, as assessed by variations in UV-vis absorption spectra, was conducted using an on-line spectrometer at various energies ranging from 10 to 30 keV. No evidence was found for specific radiation damage being energy dependent.




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Linear array detector for online diagnostics of spectral distributions at MHz repetition rates

Free-electron lasers (FELs) based on superconducting accelerator technology and storage ring facilities operate with bunch repetition rates in the MHz range, and the need arises for bunch-by-bunch electron and photon diagnostics. For photon-pulse-resolved measurements of spectral distributions, fast one-dimensional profile monitors are required. The linear array detector KALYPSO (KArlsruhe Linear arraY detector for MHz-rePetition rate SpectrOscopy) has been developed for electron bunch or photon pulse synchronous read-out with frame rates of up to 2.7 MHz. At the FLASH facility at DESY, a current version of KALYPSO with 256 pixels has been installed at a grating spectrometer as online diagnostics to monitor the pulse-resolved spectra of the high-repetition-rate FEL pulses. Application-specific front-end electronics based on MicroTCA standard have been developed for data acquisition and processing. Continuous data read-out with low latency in the microsecond range enables the integration into fast feedback applications. In this paper, pulse-resolved FEL spectra recorded at 1.0 MHz repetition rate for various operation conditions at FLASH are presented, and the first application of an adaptive feedback for accelerator control based on photon beam diagnostics is demonstrated.




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BioStruct-Africa: empowering Africa-based scientists through structural biology knowledge transfer and mentoring – recent advances and future perspectives

Being able to visualize biology at the molecular level is essential for our understanding of the world. A structural biology approach reveals the molecular basis of disease processes and can guide the design of new drugs as well as aid in the optimization of existing medicines. However, due to the lack of a synchrotron light source, adequate infrastructure, skilled persons and incentives for scientists in addition to limited financial support, the majority of countries across the African continent do not conduct structural biology research. Nevertheless, with technological advances such as robotic protein crystallization and remote data collection capabilities offered by many synchrotron light sources, X-ray crystallography is now potentially accessible to Africa-based scientists. This leap in technology led to the establishment in 2017 of BioStruct-Africa, a non-profit organization (Swedish corporate ID: 802509-6689) whose core aim is capacity building for African students and researchers in the field of structural biology with a focus on prevalent diseases in the African continent. The team is mainly composed of, but not limited to, a group of structural biologists from the African diaspora. The members of BioStruct-Africa have taken up the mantle to serve as a catalyst in order to facilitate the information and technology transfer to those with the greatest desire and need within Africa. BioStruct-Africa achieves this by organizing workshops onsite at our partner universities and institutions based in Africa, followed by post-hoc online mentoring of participants to ensure sustainable capacity building. The workshops provide a theoretical background on protein crystallography, hands-on practical experience in protein crystallization, crystal harvesting and cryo-cooling, live remote data collection on a synchrotron beamline, but most importantly the links to drive further collaboration through research. Capacity building for Africa-based researchers in structural biology is crucial to win the fight against the neglected tropical diseases, e.g. ascariasis, hookworm, trichuriasis, lymphatic filariasis, active trachoma, loiasis, yellow fever, leprosy, rabies, sleeping sickness, onchocerciasis, schistosomiasis, etc., that constitute significant health, social and economic burdens to the continent. BioStruct-Africa aims to build local and national expertise that will have direct benefits for healthcare within the continent.




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Transmission measurement at the Bernina branch of the Aramis Beamline of SwissFEL

The transmission of the optical components of the Bernina branch of the Aramis beamline at SwissFEL has been measured with an X-ray gas monitor from DESY and compared with a PSI gas detector upstream of the optical components. The transmission efficiencies of the Mo, Si and SiC mirror coatings of the Aramis beamline and the various other in-beam components were evaluated and compared with theoretical calculations, showing an agreement of 6% or better in all cases. The experiment has also shown the efficacy of the high-harmonic rejection mirrors at the Bernina branch of the Aramis beamline at SwissFEL, and characterized the transmission efficiency of the on-line spectrometer in the Aramis beamline. The theoretical transmission of the mirror coatings match the experimental data to within 7%. The accuracy of these measurements was checked against a radiative bolometer from a Japanese collaboration and found to agree to a level of 4% or better. Further comparisons with a diamond detector from a US-based inter-institute collaboration demonstrated a good agreement for the attenuator settings of the beamline.




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X-ray fluorescence analysis of metal distributions in cryogenic biological samples using large-acceptance-angle SDD detection and continuous scanning at the Hard X-ray Micro/Nano-Probe beamline P06 at PETRA III

A new Rococo 2 X-ray fluorescence detector was implemented into the cryogenic sample environment at the Hard X-ray Micro/Nano-Probe beamline P06 at PETRA III, DESY, Hamburg, Germany. A four sensor-field cloverleaf design is optimized for the investigation of planar samples and operates in a backscattering geometry resulting in a large solid angle of up to 1.1 steradian. The detector, coupled with the Xspress 3 pulse processor, enables measurements at high count rates of up to 106 counts per second per sensor. The measured energy resolution of ∼129 eV (Mn Kα at 10000 counts s−1) is only minimally impaired at the highest count rates. The resulting high detection sensitivity allows for an accurate determination of trace element distributions such as in thin frozen hydrated biological specimens. First proof-of-principle measurements using continuous-movement 2D scans of frozen hydrated HeLa cells as a model system are reported to demonstrate the potential of the new detection system.




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Characterization of the soft X-ray spectrometer PEAXIS at BESSY II

The performance of the recently commissioned spectrometer PEAXIS for resonant inelastic soft X-ray scattering (RIXS) and X-ray photoelectron spectroscopy and its hosting beamline U41-PEAXIS at the BESSY II synchrotron are characterized. The beamline provides linearly polarized light from 180 eV to 1600 eV allowing for RIXS measurements in the range 200–1200 eV. The monochromator optics can be operated in different configurations to provide either high flux with up to 1012 photons s−1 within the focal spot at the sample or high energy resolution with a full width at half maximum of <40 meV at an incident photon energy of ∼400 eV. The measured total energy resolution of the RIXS spectrometer is in very good agreement with theoretically predicted values obtained by ray-tracing simulations. PEAXIS features a 5 m-long RIXS spectrometer arm that can be continuously rotated about the sample position by 106° within the horizontal photon scattering plane, thus enabling the study of momentum-transfer-dependent excitations. Selected scientific examples are presented to demonstrate the instrument capabilities, including measurements of excitations in single-crystalline NiO and in liquid acetone employing a fluid cell sample manipulator. Planned upgrades of the beamline and the RIXS spectrometer to further increase the energy resolution to ∼100 meV at 1000 eV incident photon energy are discussed.




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A five-axis parallel kinematic mirror unit for soft X-ray beamlines at MAX IV

With the introduction of the multi-bend achromats in the new fourth-generation storage rings the emittance has decreased by an order of magnitude resulting in increased brightness. However, the higher brightness comes with smaller beam sizes and narrower radiation cones. As a consequence, the requirements on mechanical stability regarding the beamline components increases. Here an innovative five-axis parallel kinematic mirror unit for use with soft X-ray beamlines using off-axis grazing-incidence optics is presented. Using simulations and measurements from the HIPPIE beamline at the MAX IV Laboratory it is shown that it has no Eigen frequencies below 90 Hz. Its positioning accuracy is better than 25 nm linearly and 17–35 µrad angularly depending on the mirror chamber dimensions.




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A portable on-axis laser-heating system for near-90° X-ray spectroscopy: application to ferropericlase and iron silicide

A portable IR fiber laser-heating system, optimized for X-ray emission spectroscopy (XES) and nuclear inelastic scattering (NIS) spectroscopy with signal collection through the radial opening of diamond anvil cells near 90°with respect to the incident X-ray beam, is presented. The system offers double-sided on-axis heating by a single laser source and zero attenuation of incoming X-rays other than by the high-pressure environment. A description of the system, which has been tested for pressures above 100 GPa and temperatures up to 3000 K, is given. The XES spectra of laser-heated Mg0.67Fe0.33O demonstrate the potential to map the iron spin state in the pressure–temperature range of the Earth's lower mantle, and the NIS spectra of laser-heated FeSi give access to the sound velocity of this candidate of a phase inside the Earth's core. This portable system represents one of the few bridges across the gap between laser heating and high-resolution X-ray spectroscopies with signal collection near 90°.




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Limited angle tomography for transmission X-ray microscopy using deep learning

In transmission X-ray microscopy (TXM) systems, the rotation of a scanned sample might be restricted to a limited angular range to avoid collision with other system parts or high attenuation at certain tilting angles. Image reconstruction from such limited angle data suffers from artifacts because of missing data. In this work, deep learning is applied to limited angle reconstruction in TXMs for the first time. With the challenge to obtain sufficient real data for training, training a deep neural network from synthetic data is investigated. In particular, U-Net, the state-of-the-art neural network in biomedical imaging, is trained from synthetic ellipsoid data and multi-category data to reduce artifacts in filtered back-projection (FBP) reconstruction images. The proposed method is evaluated on synthetic data and real scanned chlorella data in 100° limited angle tomography. For synthetic test data, U-Net significantly reduces the root-mean-square error (RMSE) from 2.55 × 10−3 µm−1 in the FBP reconstruction to 1.21 × 10−3 µm−1 in the U-Net reconstruction and also improves the structural similarity (SSIM) index from 0.625 to 0.920. With penalized weighted least-square denoising of measured projections, the RMSE and SSIM are further improved to 1.16 × 10−3 µm−1 and 0.932, respectively. For real test data, the proposed method remarkably improves the 3D visualization of the subcellular structures in the chlorella cell, which indicates its important value for nanoscale imaging in biology, nanoscience and materials science.




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X-ray absorption linear dichroism at the Ti K-edge of rutile (001) TiO2 single crystal

X-ray absorption linear dichroism of rutile TiO2 at the Ti K-edge provides information about the electronic states involved in the pre-edge transitions. Here, linear dichroism with high energy resolution is analyzed in combination with ab initio finite difference method calculations and spherical tensor analysis. It provides an assignment of the three pre-edge peaks beyond the octahedral crystal field splitting approximation and estimates the spatial extension of the corresponding final states. It is then discussed for the first time the X-ray absorption (XAS) of pentacoordinated titanium atoms due to oxygen vacancies and it is found that, similarly to anatase TiO2, rutile is expected to exhibit a transition on the low-energy side of peak A3. Its apparent absence in the experiment is related to the degree of p–d orbital mixing which is small in rutile due to its centrosymmetric point group. A recent XAS linear dichroism study on anatase TiO2 single crystals has shown that peak A2 has an intrinsic origin and is due to a quadrupolar transition to the 3d energy levels. In rutile, due to its centrosymmetric point group, the corresponding peak A2 has a small dipole moment explaining the weak transition. The results are confronted with recent picosecond X-ray absorption spectroscopy on rutile TiO2 nanoparticles.




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Foreword to the special virtual issue dedicated to the proceedings of the PhotonDiag2018 workshop on FEL Photon Diagnostics, Instrumentation, and Beamlines Design




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Contributions of charge-density research to medicinal chemistry

Contributions of experimental and selected theoretical charge-density research to medicinal chemistry are reviewed; combining experimental methods from high-resolution small-molecule and macromolecular crystallography with theory proves to be fruitful.




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Correlated changes in structure and viscosity during gelatinization and gelation of tapioca starch granules

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




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Diffuse scattering and partial disorder in complex structures

This review discusses the state of the field of single-crystal diffuse scattering (SCDS), including detectors, data collection and the modelling techniques. High quality, three-dimensional volumes of SCDS data can now be collected at synchrotron light sources, allowing increasingly detailed and quantitative analyses to be undertaken.




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Structure and function of dioxygenases in histone demethylation and DNA/RNA demethylation

The structure and function of dioxygenases in histone demethylation and DNA/RNA dimethylation are discussed.




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EXAFS and XANES analysis of oxides at the nanoscale

This work presents a discussion of the possibilities offered by X-ray absorption spectroscopy (XAS) to study the local structure of nanomaterials. The current state of the art for the interpretation of extended X-ray absorption fine structure (EXAFS), including an advanced approach based on the use of classical molecular dynamics, is described and exemplified in the case of NiO nanoparticles. In addition, the limits and possibilities of X-ray absorption near-edge spectroscopy (XANES) in determining several effects associated with the nanocrystalline nature of materials are also discussed in connection with the development of ZnO-based dilute magnetic semiconductors and iron oxide nanoparticles.




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Binding site asymmetry in human transthyretin: insights from a joint neutron and X-ray crystallographic analysis using perdeuterated protein

A neutron crystallographic study of perdeuterated transthyretin reveals important aspects of the structure relating to its stability and its propensity to form fibrils, as well as evidence of a single water molecule that affects the symmetry of the two binding pockets.




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In-depth analysis of subclass-specific conformational preferences of IgG antibodies

An extended analysis of structural ensembles obtained from small-angle X-ray scattering data reveals subclass-specific conformational preferences of IgG antibodies, which are largely determined by the hinge-region structure.




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A modulation wave approach to the order hidden in disorder

A modulation wave approach is used to interpret the coupled longer range as well as truly short range order hidden in the highly structured diffuse intensity distributions of three representative such systems. The longer range as well as the truly short range order simultaneously encoded in such highly structured diffuse intensity distributions is highlighted.