bluuebunny/crossref_metadata_2025 huggingface dataset:
Nephrology and Coronavirus Disease 2019
Authors: Bharati Joyita , Ramachandran Raja
Published: July 2020

Novel coronavirus disease 2019 (COVID-19) has emerged as a threat to the human population worldwide. Old age and presence of comorbidities are risk factors for severe complications of the disease, as many of these patients are not able to mount effective or have an aberrant antiviral response. Patients with chronic kidney disease are at high risk of COVID-19 and its complications, especially those with end-stage renal disease (ESRD). Patients have repeated exposure to crowding in dialysis units, and face the uncertainties of health care system sustainability during periods of increasing demand and scarce supply. Acute kidney injury (AKI) is a notable complication in patients with COVID-19 with an incidence of up to 25% in specific populations. Patients with AKI have a higher mortality rate. The etiology and pathogenesis of AKI in COVID-19 are multifactorial. Direct viral invasion and cytopathic effects on renal tubular cells and indirect factors like hypovolemia, rhabdomyolysis, renal vein congestion, and hypercoagulable state play a role in causing AKI in these patients. Renal replacement therapy in the form of continuous renal replacement therapy is most widely used worldwide mostly due to hemodynamic instability of critically sick patients with COVID-19. Anticoagulation therapy is critical as most COVID-19 patients have increased clotting tendency and extracorporeal circuit thrombosis is common. ESRD patients in China had mild-to-moderate symptoms commonly. However, the data from Spain and Italy report a higher mortality rate in ESRD patients than the general population. Strict screening and uniform adherence to infection control practices have led to a decreased risk of cross-infection among other patients and dialysis personnel in dialysis units. The association between nephrology and COVID-19 is unique and focus on further research on kidney pathology along with the strengthening of existing dialysis facilities are needed.
Designer Mg−Mg and Zn−Zn single bonds facilitated by double
aromaticity in the M2B7− (M=Mg, Zn)
clusters
Authors: Wang Wei , Wang Jie , Gong Chu , Mu Chaonan , Zhang Dongmei , Zhang Xinxing
Published: July 2020

The simple homodinuclear M-M single bonds for group II and XII elements are difficult to obtain as a result of the fulfilled s2 electronic configurations, consequently, a dicationic prototype is often utilized to design the M+ −M+ single bond. Existing studies generally use sterically bulky organic ligands L− to synthesize the compounds in the L− −M+ −M+ −L− manner. However, here we report the design of Mg-Mg and Zn-Zn single bonds in two ligandless clusters, Mg2B7− and Zn2B7−, using density functional theory methods. The global minima of both of the clusters are in the form of M22+(B73−), where the M-M single bonds are positioned above a quasi-planar hexagonal B7 moiety. Chemical bonding analyses further confirm the existence of Mg-Mg and Zn-Zn single bonds in these clusters, which are driven by the unusually stable B73− moiety that is both σ and π aromatic. Vertical detachment energies of Mg2B7− and Zn2B7− are calculated to be 2.79 eV and 2.94 eV, respectively, for the future comparisons with experimental data.
Fabrication of PdSe2/GaAs heterojunction for sensitive near-infrared photovoltaic detector and image sensor application
Authors: Luo Lin-bao , Zhang Xiu-xing , Li Chen , Li Jia-xiang , Zhao Xing-yuan , Zhang Zhi-xiang , Chen Hong-yun , Wu Di , Liang Feng-xia
Published: July 2020

In this study, we have developed a high-sensitivity, near-infrared photodetector based on PdSe2/GaAs heterojunction, which was made by transferring a multilayered PdSe2 film onto a planar GaAs. The as-fabricated PdSe2/GaAs heterojunction device exhibited obvious photovoltaic behavior to 808 nm illumination, indicating that the near-infrared photodetector can be used as a self-driven device without external power supply. Further device analysis showed that the hybrid heterojunction exhibited a high on/off ratio of 1.16×105 measured at 808 nm under zero bias voltage. The responsivity and specific detectivity of photodetector were estimated to be 171.34 mA/W and 2.36×1011 Jones, respectively. Moreover, the device showed excellent stability and reliable repeatability. After 2 months, the photoelectric characteristics of the near-infrared photodetector hardly degrade in air, attributable to the good stability of the PdSe2. Finally, the PdSe2/GaAs-based heterojunction device can also function as a near-infrared light sensor.
Click-formed polymer gels with aggregation-induced emission and dual stimuli-responsive behaviors
Authors: Shi Sheng-yu , Zhang Guo-ying
Published: July 2020

Stimuli-responsive polymer gels have recently attracted great attention due to their heat/solvent resistance, dimensional stability, and unique sensitivity to external stimuli. In this work, we synthesized thiol-functionalized tetraphenylethylene (TPE) and constructed polymer gels through thiol-ene click reaction. The synthetic process of the polymer gels could be monitored by fluorescence emission of TPE moieties based on aggregation-induced emission mechanism. In addition, due to the dual redoxand acid responsiveness of the polymer gels, in the presence of dithiothreitol and trifluoroacetic acid, fluorescence quenching of the polymer gels can be observed. This stimuli-responsive characteristics endows the polymer gels with potential applications in fluorescent sensing and imaging, cancer diagnosis and selfhealing materials.
Bottom tunnel junction blue light-emitting field-effect transistors
Authors: Bharadwaj Shyam , Lee Kevin , Nomoto Kazuki , Hickman Austin , van Deurzen Len , Protasenko Vladimir , Xing Huili (Grace) , Jena Debdeep
Published: July 2020

A recent thrust toward efficient modulated light emitters for use in Li-Fi communications has sparked renewed interest in visible III-N InGaN light-emitting diodes (LEDs). With their high external quantum efficiencies, blue InGaN LEDs are ideal components for such devices. We report a method for achieving voltage-controlled gate-modulated light emission using monolithic integration of fin- and nanowire-n–i–n vertical FETs with bottom-tunnel junction planar blue InGaN LEDs. This method takes advantage of the improved performance of bottom-tunnel junction LEDs over their top-tunnel junction counterparts, while allowing for strong gate control on a low-cross-sectional area fin or wire without sacrificing the LED active area as in lateral integration designs. Electrical modulation of five orders and an order of magnitude of optical modulation are achieved in the device.
Measurement uncertainty evaluation model of field type circle time-grating sensor
Authors: Yang Hongtao , Li Li , Zhang Liusha , Zhou Jiao , Peng Donglin
Published: July 2020

A sensor uncertainty evaluation model that meets international GUM standards can provide a theoretical foundation for optimizing sensor structure parameters. In this study, a field type circle time-grating sensor was taken as the research object to build an effective uncertainty evaluation model. First, four main uncertainty sources of the field type circle time-grating sensor were found by deducing the mathematical expression of angle measurement and analyzing the sensor uncertainty sources. Second, the transitive relations between the main uncertainty sources and synthetic uncertainty were analyzed and deduced, respectively. Finally, an uncertainty evaluation model with all the main uncertainty sources was built based on modern uncertainty theory. A field type circle time-grating sensor with 72 poles was tested to verify the effectiveness of the proposed uncertainty evaluation model. The results indicated that the evaluation process in the experiment meets the international GUM standards. The peak-to-peak value of the measurement error for the whole week of the field type time grating in this study was 12.09′′. This value was in agreement with the 12.73′′ calculated from the formula of measurement uncertainty evaluation of the field type time grating, which can be used for the actual evaluation of field time grating measurement uncertainty. Moreover, the analysis results can provide a theoretical basis for the optimal design of the time grating sensor structure.
Extended detrended fluctuation analysis of electroencephalograms signals during sleep and the opening of the blood–brain barrier
Authors: Pavlov A. N. , Dubrovsky A. I. , Koronovskii A. A. , Pavlova O. N. , Semyachkina-Glushkovskaya O. V. , Kurths J.
Published: July 2020

Detrended fluctuation analysis (DFA) is widely used to characterize long-range power-law correlations in complex signals. However, it has restrictions when nonstationarity is not limited only to slow variations in the mean value. To improve the characterization of inhomogeneous datasets, we have proposed the extended DFA (EDFA), which is a modification of the conventional method that evaluates an additional scaling exponent to take into account the features of time-varying nonstationary behavior. Based on EDFA, here, we analyze rat electroencephalograms to identify specific changes in the slow-wave dynamics of brain electrical activity associated with two different conditions, such as the opening of the blood–brain barrier and sleep, which are both characterized by the activation of the brain drainage function. We show that these conditions cause a similar reduction in the scaling exponents of EDFA. Such a similarity may represent an informative marker of fluid homeostasis of the central nervous system.
Transcranial focused ultrasound generates skull-conducted shear waves: Computational model and implications for neuromodulation
Authors: Salahshoor Hossein , Shapiro Mikhail G. , Ortiz Michael
Published: July 2020

Focused ultrasound (FUS) is an established technique for non-invasive surgery and has recently attracted considerable attention as a potential method for non-invasive neuromodulation. While the pressure waves in FUS procedures have been extensively studied in this context, the accompanying shear waves are often neglected due to the relatively high shear compliance of soft tissues. However, in bony structures such as the skull, acoustic pressure can also induce significant shear waves that could propagate outside the ultrasound focus. Here, we investigate wave propagation in the human cranium by means of a finite-element model that accounts for the anatomy, elasticity, and viscoelasticity of the skull and brain. We show that, when a region on the scalp is subjected to FUS, the skull acts as a waveguide for shear waves that propagate with a speed close to 1500 m/s, reaching off-target structures such as the cochlea. In particular, when a sharp onset of FUS is introduced in a zone proximal to the intersection of the parietal and temporal cranium, the bone-propagated shear waves reach the inner ear in about 40 μs, leading to cumulative displacements of about 1 μm. We further quantify the effect of ramped and sharp application of FUS on the cumulative displacements in the inner ear. Our results help explain the off-target auditory responses observed during neuromodulation experiments and inform the development of mitigation and sham control strategies.
Numerical simulation of rheological behavior of polymer in three layer co-extrusion process
Authors: Wang Chao , Lei Min
Published: July 2020

The two-dimensional rheological models of the three-layer co-extrusion process for the generalized Newtonian fluid were established. Meanwhile, the flow characteristics of melts in the die channels were numerically simulated using the finite element method to explain the influence of the structure change of flow channels in the die section on the rheological behavior of melts. The simulation results indicated that the changes in the convergence angle of flow channels have certain impacts on the shift of the confluence interface of the three-layer co-extruded melt flow while little effects on the interface shape at the outlet. The flow ratio of the melt in each layer at the entrance has a significant effect on the interface shift. The flowing pressure of melts in the die is mainly determined by the inclination angle of flow channels while less influenced by the fact whether the inlets of the flow channels in each layer are smoothed or not.
Wet chemical etching of single-bore microstructured silicon dioxide fibers
Authors: Giddings Josef A. , Stokes Yvonne M. , Bachus Kyle J. , Ebendorff-Heidepriem Heike
Published: July 2020

We model the process of wet chemical etching of the external surface of a single-bore microstructured silicon dioxide fiber in hydrofluoric acid (HFA) while water is pumped through the internal channel to prevent etching of it. The model uses the Stokes flow for the velocity throughout the system and the advection–diffusion equation for the concentration of HFA. We determine the etch rate as a function of HFA concentration using data from experiments designed for this purpose, from which we calculate the change in the fiber surface. We solve our equations using a time-stepping finite-element method and verify our model by comparing to results found experimentally. We investigate the effects of different water flow rates, diffusivity, buoyancy, and bore radius. We find the water being pumped through the bore does not fully protect it and there is some etching of the internal channel, which is difficult to see in experimental images. We also obtain an estimate of the diffusivity of high-concentration HFA in water.
BaGa2GeS6 and BaGa2GeSe6 crystals for nonlinear optical frequency conversion
Authors: Grechin S.G. , Nikolaev P.P. , Ionin A.A. , Kinyaevskii I.O. , Andreev Yu.M.
Published: July 2020

We analyse the functional capabilities of new crystals, BaGa2GeS6 (BGGS) and BaGa2GeSe6 (BGGSe), which are used for nonlinear optical frequency conversion in their transparency range. The wavelengths at which maximum conversion efficiencies can be obtained and the tuning range for difference-frequency generation are found. It is shown that there are wavelength combinations at which the effective nonlinearity coefficient varies only slightly in a wide frequency band.
Scheme for stabilising the phase and arrival time of ultrashort laser pulses in a coherent beam combining fibre system
Authors: Andrianov A.V. , Korobeynikova A.P.
Published: July 2020

An algorithm has been demonstrated for simultaneously measuring the phase and arrival time of optical pulses relative to pulses in a reference channel using one detector array. Based on this algorithm, a simple optoelectronic pulse phase and arrival time stabilisation scheme has been designed for operation in a coherent beam combining fibre system for ultrashort pulses (including chirped ones). We have studied the performance of the stabilisation scheme. In particular, we have reached a phase measurement rate of 25 000 cps, demonstrated an ∼ 2 kHz limiting phase stabilisation frequency in a feedback loop, and obtained an arrival time measurement accuracy of ∼ 5 % of the transform-limited pulse duration at a measurement rate of 5 cps. In experiments concerned with coherent beam combining for two channels of a pulsed fibre system at a wavelength of 1030 nm, we have demonstrated phase stabilisation with an accuracy better than λ/100 and delay setting accuracy of 10 fs at a transform-limited pulse duration of ∼ 200 fs and obtained 94 % beam combining efficiency.
Molecular characterization of a fungal gasdermin-like protein
Authors: Daskalov Asen , Mitchell Patrick S. , Sandstrom Andrew , Vance Russell E. , Glass N. Louise
Published: July 2020

Significance

Numerous cell death-controlling genes have been identified in fungi, especially in the context of conspecific nonself discrimination (allorecognition). However, our understanding of the molecular mechanisms by which these genes trigger programmed cell death (PCD) is limited, as is our knowledge about their relation to PCD pathways in other major eukaryotic kingdoms. Here, we show that the cell death-inducing RCD-1 protein from
Neurospora crassa
is related to the cytotoxic N-terminal domain of gasdermin, which is the executioner of inflammatory cell death reaction in mammals termed pyroptosis. Our work documents an evolutionary transkingdom relationship of cell death execution proteins between fungi and animals.
Single administration of resveratrol improves social behavior in adult mouse models of autism spectrum disorder
Authors: Hidema Shizu , Kikuchi Shohei , Takata Ryoji , Yanai Takaaki , Shimomura Kenju , Horie Kengo , Nishimori Katsuhiko
Published: July 2020

Resveratrol (RSV) is a natural polyphenol present in grapes, the skin of peanuts, and several other plants with many health benefits. Autism spectrum disorder (ASD) is a neurodevelopmental disorder that may be linked to neural and synaptic development impairments. The present study aimed to analyze the preventive effects of RSV on the development of ASD-like behavior, using oxytocin receptor gene knockout (Oxtr-KO) and valproic acid-induced ASD (VPA-ASD) model mice. Genetic deficiencies in Oxtr are suggested to be involved in ASD etiology. Twenty-four hours after a single RSV injection to the Oxtr-KO mice, the social impairments caused by OXTR deficiency were ameliorated. RSV also improved social impairments in the VPA-ASD mice. Administration of RSV up-regulated silent information regulator 1 (Sirt1) gene and early growth response factor 3 (Egr3) gene expressions in the amygdala of the Oxtr-KO mice. Our data suggest that RSV may have therapeutic effects on ASD with multiple targets.
Acute effects of lactic acid-fermented and enzyme-digested soybean on protein synthesis via mTOR signaling in the skeletal muscle
Authors: Ono Kohei , Tanaka Minoru , Ikeji Takuya , Nakanishi Ryosuke , Hirabayashi Takumi , Tategaki Airo , Kondo Hiroyo , Ishihara Akihiko , Fujino Hidemi
Published: July 2020

Protein-containing nutrients result in the efficient hypertrophy of muscles by increasing muscle protein synthesis. Soybean is often ingested by athletes or individuals who exercise; however, it takes very long to be absorbed. Lactic acid-fermented and enzyme-digested (LFED) soybean is absorbed faster than untreated soybean. This study aims at determining muscle protein synthesis after ingesting a single bolus of soybean or LFED soybean produced by lactic acid bacteria and protease digestion. Eight-week-old overnight-fasted ICR mice were administered powdered or LFED soybean. Mice were euthanized at 7, 15, 30, 60, 90, and 120 min after soybean intake. We have demonstrated that LFED soybean administration was quicker in stimulating muscle protein synthesis by activating mammalian target of rapamycin (mTOR) signaling than orally ingesting untreated soybean in the gastrocnemius muscle. These results suggested that LFED soybean is a more efficient source of nutrition for muscle hypertrophy than untreated soybean.
Bilateral deficit in strength but not rapid force during maximal handgrip contractions
Authors: Carr Joshua C. , Bemben Michael G. , Black Christopher D. , Ye Xin , Defreitas Jason M.
Published: July 2020

The purpose of this experiment was to evaluate the bilateral index in force and electromyographic (EMG) responses for the dominant and non‐dominant hands during maximal handgrip contractions in males and females. Thirty‐two right‐handed participants (16 females) performed maximal unilateral and bilateral handgrip contractions on two separate visits. Bilateral indices were computed for maximal force, rate of force development (RFD100), EMG amplitude, and the rate of EMG rise (RER). There was a bilateral deficit for maximal force in the dominant (−4.98 ± 7.39%, p < 0.001; d = 0.674) but not the non‐dominant hand (−1.57 ± 9.10%, p = 0.334; d = 0.173). No deficits were observed for rapid force. The non‐dominant flexor carpi radialis showed a bilateral facilitation in EMG amplitude (+12.32 ± 19.29%, p < 0.001; d = 0.638), yet a bilateral deficit for RER (−22.10 ± 27.80%, p < 0.001; d = 0.795). No sex differences were observed for any of the bilateral indices. These data suggest that maximal but not rapid force is susceptible to a bilateral deficit during contractions of the hands. The EMG responses did not parallel the force data. We show sex does not influence the magnitude or direction of the bilateral index in this muscle group.
Deorphanizing FAM19A proteins as pan-neurexin ligands with an unusual biosynthetic binding mechanism
Authors: Khalaj Anna J. , Sterky Fredrik H. , Sclip Alessandra , Schwenk Jochen , Brunger Axel T. , Fakler Bernd , Südhof Thomas C.
Published: July 2020

Neurexins are presynaptic adhesion molecules that organize synapses by binding to diverse trans-synaptic ligands, but how neurexins are regulated is incompletely understood. Here we identify FAM19A/TAFA proteins, “orphan" cytokines, as neurexin regulators that interact with all neurexins, except for neurexin-1γ, via an unusual mechanism. Specifically, we show that FAM19A1-A4 bind to the cysteine-loop domain of neurexins by forming intermolecular disulfide bonds during transport through the secretory pathway. FAM19A-binding required both the cysteines of the cysteine-loop domain and an adjacent sequence of neurexins. Genetic deletion of neurexins suppressed FAM19A1 expression, demonstrating that FAM19As physiologically interact with neurexins. In hippocampal cultures, expression of exogenous FAM19A1 decreased neurexin O-glycosylation and suppressed its heparan sulfate modification, suggesting that FAM19As regulate the post-translational modification of neurexins. Given the selective expression of FAM19As in specific subtypes of neurons and their activity-dependent regulation, these results suggest that FAM19As serve as cell type–specific regulators of neurexin modifications.
Fault diagnosis of key components in the rotating machinery based on Fourier transform multi-filter decomposition and optimized LightGBM
Authors: Zhang Changhe , Kong Li , Xu Qi , Zhou Kaibo , Pan Hao
Published: July 2020

Rotating machinery is a primary element of mechanical equipment, and thus fault diagnosis of its key components is very important to improve the reliability and safety of modern industrial systems. The key point to diagnose the faults of these components is to extract effectively the hidden fault information. However, the actual vibration signals of rotating machinery have nonlinear and non-stationary characteristics, so traditional signal decomposition methods are unable to extract the frequency components accurately, leading to spectrum overlap of the decomposed sub-signals. Therefore, a rotating machinery fault diagnosis approach based on Fourier transform multi-filter decomposition (FTMFD), fuzzy entropy (FE), joint mutual information maximization (JMIM), and a light gradient boosting machine (LightGBM), is proposed in this paper. FTMFD is used to extract the frequency domain information of the raw vibration signals, whereas FE is used to calculate and extract the fault information of the decomposed sub-signals. Then feature selection is carried out by using JMIM to reduce the influence of redundant features on data analysis and classification accuracy. Furthermore, LightGBM is used to rank the candidate features and outputs the fault diagnosis result. Experimental results from two real datasets show that the proposed method achieves higher accuracy with fewer features than some existing methods for fault recognition. Various working conditions are also considered and verified.
A new traceability chain for luminance scale with LED-based transfer standard
Authors: Godo Kenji
Published: July 2020

A new traceability chain for luminance scale is proposed for light-emitting diode (LED) luminance measurement, which utilizes a newly developed LED-based luminance standard source (luminance standard LED) as a transfer standard. Compared with conventional traceability chains for LED luminance measurement that rely on either a luminance meter to transfer the scale from the primary to the user level, the proposed scheme has a two-fold advantage. Firstly, color correction is made at the traceability source and the user is freed from performing this complicated task. Secondly, the luminance standard LED acts as the reference source for comparison measurement with a luminance meter and no other extended source facilities such as integrating spheres are necessary at the user site. Performance evaluation of the luminance standard LEDs showed spatial uniformity better than ±2.0% within a 7 mm diameter area and temporal stability of 0.01% during an 8 h operation, which verified the LEDs’ capability to serve as a reference standard source. Calibration of the luminance standard LED was performed on the luminance scale realized by illuminance to luminance conversion, and the calibration uncertainty was estimated to be U = 1.4% to 1.7% (k = 2) at the traceability source. It is expected that this will enable users to obtain luminance measurement uncertainties comparable to the conventional traceability schemes while profiting from the high practicability that the proposed scheme provides. The luminous standard LEDs are now used in a new traceability chain in Japan, contributing to improved reliability of the luminance measurement of a wide range of LED-based products such as displays.
N2 plasma-activated NiO nanosheet arrays with enhanced water splitting performance
Authors: Sai K Naga Sathya , Tang Yuanhao , Dong Lin , Yu Xin-Yao , Hong Zhanglian
Published: July 2020

NiO is a promising electrocatalyst for electrochemical energy conversion due to its rich redox sites, low cost, and ease of synthesis. However, hindered by low electrical conductivity and limited electrocatalytic active sites, bare NiO usually exhibits poor electrochemical performance towards hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Herein, we develop an N2 plasma activation approach to simultaneously improve both HER and OER activity of NiO by constructing heterostructured Ni/Ni3N/NiO nanosheet arrays on Ni foam. The optimized N2 plasma-activated NiO nanosheet arrays for HER and OER (denoted as P-NiO-HER and P-NiO-OER) only need an overpotential of 46 and 294 mV, respectively, to achieve 10 mA cm−2. Moreover, for overall water splitting, the assembled electrolysis cell with P-NiO-HER and P-NiO-OER as the cathode and anode, respectively, only requires a small voltage of 1.57 V to deliver 10 mA cm−2. Remarkably, the plasma-activated NiO nanosheet arrays exhibit excellent stability for up to 50 h for HER, OER, and full water electrolysis. The strategy developed here to activate the electrocatalytic performance of metal oxides opens a new door for water splitting.
Tailored voltage waveforms applied to a capacitively coupled chlorine discharge
Authors: Skarphedinsson G A , Gudmundsson J T
Published: July 2020

Tailored voltage waveform, composed of a fundamental frequency and the second harmonic, is applied to a capacitively coupled chlorine discharge operated in the pressure range 1–50 Pa. The electronegativity is very high and the electron power absorption is mainly due to drift-ambipolar (DA) electron power absorption within the electronegative core. For operating pressures of 1 and 10 Pa the creation of a dc self-bias and asymmetric response is demonstrated and applied to control the ion bombardment energy while the ion flux on the electrodes remains fixed. However, the available range in mean ion energy is rather limited and the range is significantly narrower than typically observed for electropositive discharges. For operating pressure of 50 Pa it is not possible to control the ion bombardment energy by the phase angle between the fundamental frequency and the second harmonic. At the low pressure of 1 Pa the power absorption by

C
l

2

+

ions dominate, while power absorption by electrons is smaller. At higher operation pressure DA power absorption by electrons dominates. The electric field within the electronegative core is high and not constant within the plasma bulk and exhibits the waveform of the discharge driving voltage for both the single frequency and dual frequency operation.
Restoring geometrical optics near caustics using sequenced metaplectic transforms
Authors: Lopez N A , Dodin I Y
Published: July 2020

Geometrical optics (GO) is often used to model wave propagation in weakly inhomogeneous media and quantum-particle motion in the semiclassical limit. However, GO predicts spurious singularities of the wavefield near reflection points and, more generally, at caustics. We present a new formulation of GO, called metaplectic geometrical optics (MGO), that is free from these singularities and can be applied to any linear wave equation. MGO uses sequenced metaplectic transforms of the wavefield, corresponding to symplectic transformations of the ray phase space, such that caustics disappear in the new variables and GO is reinstated. The Airy problem and the quantum harmonic oscillator are described analytically using MGO for illustration. In both cases, the MGO solutions are remarkably close to the exact solutions and remain finite at cutoffs, unlike the usual GO solutions.
Polymer carriers for controlled fragrance release
Authors: Wei Min , Pan Xi , Rong Lin , Dong Aijun , He Yunlu , Song Xuyan , Li Junsheng
Published: July 2020

Fragrance is a class of material commonly used in many consumer products such as food and tobacco. Since most of the fragrance is highly volatile, the successful use of fragrance in practical application requires effective preservation of fragrance with appropriate substrate material. As a low cost and versatile material, polymer holds great promise as a fragrance carrier. In this review, we summarize representative polymer carriers developed recently for sustained and controlled release of fragrance, which include natural polymers and novel synthetic polymers. The results summarized in this mini-review would shed light on the future design of advanced fragrance carrier for various applications.
NASA renames space telescope
Authors: Cooper Keith
Published: July 2020

NASA’s troubled space telescope, WFIRST, has been renamed the Nancy Grace Roman Space Telescope in honour of NASA’s former chief of astronomy.
South Africa targets ground station
Authors: Makoni Munyaradzi
Published: July 2020

A new deep-space ground station to support human spaceflight missions to the Moon and Mars is set to be built in South Africa. The South African National Space Agency (SANSA) and NASA have agreed to study where the station could be established.
Growing the gravitational-wave network
Authors: Reitze David
Published: July 2020

David Reitze, executive director of the Laser Interferometer Gravitational-Wave Observatory, talks to Richard Blaustein about how gravitational-wave observations are set for a multi-detector boost
Training a computer to hunt cancer
Authors: Harris Margaret
Published: July 2020

Medical physicist and entrepreneur Maryellen Giger talks to Margaret Harris about how she established the use of AI in breast cancer imaging
Rationing care by frailty during the COVID-19 pandemic
Authors: Lewis Emma Grace , Breckons Matthew , Lee Richard P , Dotchin Catherine , Walker Richard
Published: July 2020

The coronavirus disease 2019 (COVID-19) pandemic is disproportionately affecting older people and those with underlying comorbidities. Guidelines are needed to help clinicians make decisions regarding appropriate use of limited NHS critical care resources. In response to the pandemic, the National Institute for Health and Care Excellence published guidance that employs the Clinical Frailty Scale (CFS) in a decision-making flowchart to assist clinicians in assessing older individuals’ suitability for critical care. This commentary raises some important limitations to this use of the CFS and cautions against the potential for unintended impacts.

The COVID-19 pandemic has allowed the widespread implementation of the CFS with limited training or expert oversight. The CFS is primarily being used to assess older individuals’ risk of adverse outcome in critical care, and to ration access to care on this basis. While some form of resource allocation strategy is necessary for emergencies, the implementation of this guideline in the absence of significant pressure on resources may reduce the likelihood of older people with frailty, who wish to be considered for critical care, being appropriately considered, and has the potential to reinforce the socio-economic gradient in health.

Our incomplete understanding of this novel disease means that there is a need for research investigating the short-term predictive abilities of the CFS on critical care outcomes in COVID-19. Additionally, a review of the impact of stratifying older people by CFS score as a rationing strategy is necessary in order to assess its acceptability to older people as well as its potential for disparate impacts.
National trends in prescription drug expenditures and projections for 2020
Authors: Tichy Eric M , Schumock Glen T , Hoffman James M , Suda Katie J , Rim Matthew H , Tadrous Mina , Stubbings JoAnn , Cuellar Sandra , Clark John S , Wiest Michelle D , Matusiak Linda M , Hunkler Robert J , Vermeulen Lee C
Published: July 2020

Purpose

To report historical patterns of pharmaceutical expenditures, to identify factors that may influence future spending, and to predict growth in drug spending in 2020 in the United States, with a focus on the nonfederal hospital and clinic sectors.

Methods

Historical patterns were assessed by examining data on drug purchases from manufacturers using the IQVIA National Sales Perspectives database. Factors that may influence drug spending in hospitals and clinics in 2020 were reviewed, including new drug approvals, patent expirations, and potential new policies or legislation. Focused analyses were conducted for specialty drugs, biosimilars, and diabetes medications. For nonfederal hospitals, clinics, and overall (all sectors), estimates of growth of pharmaceutical expenditures in 2020 were based on a combination of quantitative analyses and expert opinion.

Results

In 2019, overall US pharmaceutical expenditures grew 5.4% compared to 2018, for a total of $507.9 billion. This increase was driven to similar degrees by prices, utilization, and new drugs. Adalimumab was the top drug in US expenditures in 2019, followed by apixaban and insulin glargine. Drug expenditures were $36.9 billion (a 1.5% increase from 2018) and $90.3 billion (an 11.8% increase from 2018) in nonfederal hospitals and clinics, respectively. In clinics, growth was driven by new products and increased utilization, whereas in hospitals growth was driven by new products and price increases. Several new drugs that will likely influence spending are expected to be approved in 2020. Specialty and cancer drugs will continue to drive expenditures.

Conclusion

For 2020 we expect overall prescription drug spending to rise by 4.0% to 6.0%, whereas in clinics and hospitals we anticipate increases of 9.0% to 11.0% and 2.0% to 4.0%, respectively, compared to 2019. These national estimates of future pharmaceutical expenditure growth may not be representative of any particular health system because of the myriad of local factors that influence actual spending.
Documentation of contraceptive counseling in female veterans of reproductive age
Authors: Schexnayder Chandler D , King Shani , Emelogu Oluchi
Published: July 2020

Purpose

To assess the rate at which contraceptive counseling is provided to women of childbearing age prescribed teratogenic medications at Michael E. DeBakey Veterans Affairs Medical Center (MEDVAMC). Women of childbearing age comprise a large demographic of women veterans and may require contraceptive counseling in the event a potentially teratogenic medication is prescribed. According to multiple studies, overall documentation of contraceptive counseling occurs in approximately half of this population or less. The rate of documented contraceptive counseling at MEDVAMC is unknown.

Methods

A retrospective chart review of electronic health records was conducted from January 2017 to August 2018. Patients included were female veterans between 18 and 45 years of age who made 2 or more visits to MEDVAMC prior to filling a prescription for a HMG-CoA reductase inhibitor (statin), angiotensin-converting enzyme inhibitor, or angiotensin II receptor blocker. Charts were screened for documentation of contraceptive counseling (including family planning counseling), prescribed contraception, and pregnancy testing prior to dispensing of a potentially teratogenic prescription.

Results

There were 172 female veterans included in this project. Documentation of contraceptive counseling occurred in 63% (n = 108) of patients; in total, 42% (n = 73) of patients were on some form of contraception, with the most common being oral contraceptive pill (used by 30% of women).

Conclusion

The rate of documentation of contraceptive counseling at MEDVAMC was found to be higher than rates reported in national studies. As we continue to strive to provide exceptional care for our women veterans, we would like to continue to increase the education and awareness on this matter.
Selective attraction in bird-pollinated flowers. A commentary on: ‘Red flowers differ in shades between pollination systems and across continents’
Authors: Lunau Klaus , Gerten Sarah
Published: July 2020

This article comments on:

Zhe Chen, Yang Niu, Chang-Qiu Liu and Hang Sun, Red flowers differ in shades between pollination systems and across continents, Annals of Botany, Volume 126, Issue 5, 9 October 2020, Pages 837–848, https://doi.org/10.1093/aob/mcaa103
David Moss (1943–2020)
Authors: Shukurov Anvar , Brandenburg Axel , Brooke John , Sokoloff Dmitry , Tavakol Reza
Published: July 2020

Anvar Shukurov and colleagues remember a theorist known for his work on stellar and galactic magnetism, who was also a prominent marine biologist.
Jupiter's X-ray aurorae
Authors: Wibisono Affelia
Published: July 2020

Affelia Wibisono and colleagues report on XMM-Newton and Juno observations of Jupiter's magnetosphere and polar aurorae. This won the Rishbeth Prize for best student talk at the MIST session, NAM 2019.
Frontiers of seismology
Authors: Ziolkowski Anton , Bell Andrew , Browitt Christopher , Curtis Andrew , Macdonald Calum , Main Ian , Peacock Sheila , Rawlinson Nicholas , Storchak Dmitry , Walker Alice
Published: July 2020

Anton Ziolkowski and fellow organizers look back at the British Seismology Meeting 2019, which discussed events of all scales as well as new hardware and software techniques.
Geophysics on a plate
Authors: Bowler Sue
Published: July 2020

Sue Bowler rereads a classic 1971 paper on plate tectonics by Dan McKenzie and John Sclater, which highlights the geophysical heritage of the RAS.
Genetic and morphological differentiation among populations of the Rivoli’s Hummingbird (Eugenes fulgens) species complex (Aves: Trochilidae)
Authors: Zamudio-Beltrán Luz E , Ornelas Juan Francisco , Malpica Andreia , Hernández-Baños Blanca E
Published: July 2020

Genetic variation and phylogeographic studies have been crucial for understanding mechanisms of speciation. We analyzed genetic variation and phylogeography to reconstruct the demographic history of the Rivoli’s Hummingbird (Eugenes fulgens) species complex and also evaluated their morphological differentiation. This widely distributed species inhabits the highlands of Mexico and northern Central America, with 2 subspecies separated by the Isthmus of Tehuantepec (west: E. f. fulgens, east: E. f. viridiceps). We surveyed genetic variation in 2 mitochondrial DNA markers (mtDNA, with 129 individuals) and nuclear DNA (6 microsatellites, with 85 individuals). We also inferred the demographic history, estimated divergence times, and analyzed morphological variation using 470 vouchered specimens. We modeled the current potential distribution of the species using ecological niche modeling and projected it into the past to model the effects of the Pleistocene climatic cycles. Haplotype networks, pairwise FST comparisons, AMOVA, and morphological analysis revealed differences between geographically isolated populations separated by the Isthmus of Tehuantepec (IT; corresponding to the 2 recognized subspecies: fulgens and viridiceps), and by the Motagua-Polochic-Jocotán (MPJ) system fault. Demographic scenarios revealed a contraction in distribution during the last interglacial, and expansion during the Last Glacial Maximum (LGM) with little change since the LGM. Divergence between groups separated by the Isthmus of Tehuantepec ~59,600 yr ago occurred in the presence of gene flow, suggesting that the Isthmus of Tehuantepec is a semipermeable barrier to gene flow. STRUCTURE analyses of microsatellite data detected 3 genetically differentiated groups. Several results fit a model of recent lineage divergence, including a significant signal of genetic differentiation, demographic expansion, decreased gene flow from past to present, and northward expansion during the LGM and contraction during the interglacial periods. We conclude that the genetic differentiation of E. fulgens in the Madrean Pine-Oak Woodlands resulted from recent geographical isolation of populations separated by natural barriers (IT and MPJ).
Gut dysbiosis in Huntington’s disease: associations among gut microbiota, cognitive performance and clinical outcomes
Authors: Wasser Cory I , Mercieca Emily-Clare , Kong Geraldine , Hannan Anthony J , McKeown Sonja J , Glikmann-Johnston Yifat , Stout Julie C
Published: July 2020

Huntington’s disease is characterized by a triad of motor, cognitive and psychiatric impairments, as well as unintended weight loss. Although much of the research has focused on cognitive, motor and psychiatric symptoms, the extent of peripheral pathology and the relationship between these factors, and the core symptoms of Huntington’s disease, are relatively unknown. Gut microbiota are key modulators of communication between the brain and gut, and alterations in microbiota composition (dysbiosis) can negatively affect cognition, behaviour and affective function, and may be implicated in disease progression. Furthermore, gut dysbiosis was recently reported in Huntington’s disease transgenic mice. Our main objective was to characterize the gut microbiome in people with Huntington’s disease and determine whether the composition of gut microbiota are significantly related to clinical indicators of disease progression. We compared 42 Huntington’s disease gene expansion carriers, including 19 people who were diagnosed with Huntington’s disease (Total Functional Capacity > 6) and 23 in the premanifest stage, with 36 age- and gender-matched healthy controls. Participants were characterized clinically using a battery of cognitive tests and using results from 16S V3 to V4 rRNA sequencing of faecal samples to characterize the gut microbiome. For gut microbiome measures, we found significant differences in the microbial communities (beta diversity) based on unweighted UniFrac distance (P = 0.001), as well as significantly lower alpha diversity (species richness and evenness) between our combined Huntington’s disease gene expansion carrier group and healthy controls (P = 0.001). We also found major shifts in the microbial community structure at Phylum and Family levels, and identified functional pathways and enzymes affected in our Huntington’s disease gene expansion carrier group. Within the Huntington’s disease gene expansion carrier group, we also discovered associations among gut bacteria, cognitive performance and clinical outcomes. Overall, our findings suggest an altered gut microbiome in Huntington’s disease gene expansion carriers. These results highlight the importance of gut biomarkers and raise interesting questions regarding the role of the gut in Huntington’s disease, and whether it may be a potential target for future therapeutic intervention.
Normal Olfactory Functional Connectivity Despite Lifelong Absence of Olfactory Experiences
Authors: Peter Moa G , Fransson Peter , Mårtensson Gustav , Postma Elbrich M , Nordin Love Engström , Westman Eric , Boesveldt Sanne , Lundström Johan N
Published: July 2020

Congenital blindness is associated with atypical morphology and functional connectivity within and from visual cortical regions; changes that are hypothesized to originate from a lifelong absence of visual input and could be regarded as a general (re) organization principle of sensory cortices. Challenging this is the fact that individuals with congenital anosmia (lifelong olfactory sensory loss) display little to no morphological changes in the primary olfactory cortex. To determine whether olfactory input from birth is essential to establish and maintain normal functional connectivity in olfactory processing regions, akin to the visual system, we assessed differences in functional connectivity within the olfactory cortex between individuals with congenital anosmia (n = 33) and matched controls (n = 33). Specifically, we assessed differences in connectivity between core olfactory processing regions as well as differences in regional homogeneity and homotopic connectivity within the primary olfactory cortex. In contrast to congenital blindness, none of the analyses indicated atypical connectivity in individuals with congenital anosmia. In fact, post-hoc Bayesian analysis provided support for an absence of group differences. These results suggest that a lifelong absence of olfactory experience has a limited impact on the functional connectivity in the olfactory cortex, a finding that indicates a clear difference between sensory modalities in how sensory cortical regions develop.
An unusual case of Thoraflex displacement after blunt thoracic trauma during skiing
Authors: Di Marco Luca , Botta Luca , Murana Giacomo , Pacini Davide
Published: July 2020

We present a case of a patient, who had previously undergone a frozen elephant trunk procedure for acute non-A–non-B aortic dissection, and developed a traumatic new entry tear due to the displacement of the hybrid prosthesis while skiing. An emergency thoracic endovascular aortic repair was performed without postoperative complications.
Does HIV infection increase male sexual behavior?
Authors: Starks Philip T , Kelsey Maxfield M G , Rosania David , Getz Wayne M
Published: July 2020

After 40 years of intense study on HIV/AIDS, scientists have identified, among other things, at risk populations, stages of disease progression and treatment strategies. What has received less attention is the possibility that infection might elicit an increase in sexual behavior in humans. In 2000, Starks and colleagues speculated that HIV infection could alter host behavior in a manner that facilitated the spread of the virus. Retrospective and self-report data from five studies now support this hypothesis. Individuals with acute—versus nonacute—stage infections report more sexual partners and more frequent risky sex. Additionally, male sexual behavior increases nonlinearly with HIV viral load, and data suggest a potential threshold viral level above which individuals are more likely to engage in risky sexual behavior. Taken together, these data suggest that HIV infection influences male sexual behavior in a manner beneficial to the virus. Here, we present these findings, highlight their limitations and discuss alternative perspectives. We argue for increased testing of this hypothesis and advocate for increased public health measures to mitigate the putative impact on male sexual behavior.

Lay Summary In 2000, Starks and colleagues speculated that HIV infection could alter host behavior in a manner that facilitated the spread of the virus. Retrospective and self-report data from five studies now support this hypothesis. We argue for increased testing of this hypothesis and advocate for increased public health measures to mitigate the putative impact on male sexual behavior.