bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of magnetron sputtering modes of aluminum and aluminum nitride films on their surface, structure and composition
Authors: Baranova L V , Strunin V I , Chirikov N. A.
Published: April 2021

To ensure the optimal combination of the properties of the thin-film layers of piezoelectric structures and achieve the required characteristics of resonators and devices for selecting and generating of the signals based on them, the influence of technological modes of aluminum nitride films formation on the surface morphology, structure and elemental composition of films used in the construction of microelectronic bulk acoustic waves (BAW) resonator with Bragg reflector, the optimal modes are determined that satisfy the requirements for film layers for a piezoelectric transducer and Bragg reflector.
Effects of Sloped Trench Casing Treatment Combined with Air Injection on Stall Triggering Factor of a 1.5 Stage Axial Flow Compressor
Authors: Kai-kai Zou , Yong-bao Liu , You-hong Yu , Xing He
Published: April 2021

A new mode, sloped trench casing treatment combined with air injection, was designed and introduced in a 1.5 stage axial compressor. To reveal the effects of this mode on the aerodynamic stability, a three-dimensional numerical simulation was carried out. Results show that sloped trench casing treatment combined with air injection could improve the stable operating range, total pressure ratio, and adiabatic efficiency of the compressor simultaneously. The optimal configuration obtains the stable range extension of 26.47% by using only 0.69% of the whole annulus mass flow rate. Based on a comparison of the stall routes, it is found that the smooth casing compressor occurring stall is caused by a blockage cell formed mainly by the low-velocity tip leakage flow. However, the stall of the sloped trench casing compressor with air injection is caused by a considerable blockage cell formed jointly by the low-velocity tip leakage flow and separated flow on the suction surface of the middle-upper span of the rotor blade. The latter’s contribution cannot be neglected.
The Effect of Crosslinking Mixture Addition on the mechanical properties of PU Polymeric Matrix
Authors: Boshra Islam K. , Lin Guo , Elhedery Tarek
Published: April 2021

Polyurethanes are prepared by extending a prepolymer chains made from a macro diol and a diisocyanate and its mechanical properties could be improved by using special additives to enhance the crosslinking process. In this study, 15 hydroxyl terminated polybutadiene (HTPB) based poly urethanes were prepared using 1, 6- hexamethylene diisocyanate (HMDI) and crosslinking mixture (CM) consists of trimethylol propane (TMP) as a triol crosslinker and butane diol (BD) as a chain extender. Five different crosslinking mixtures were used through the combination between TMP: BD = 1:0, 0:1, 1:1, 2:1 and 1:2. The research investigated the impact occurred on the mechanical behaviour of PU formulations prepared by adding certain cross-linking additives with various content from 0 % to 5 % and the curing ratio NCO/OH maintained constant at 0.7. The strength-strain relationships of all the finished samples were determined by using a LLOYD testing machine. The mechanical properties have been plotted vs. crosslinking mixture content and TMP: BD percentage which could be utilized to choose an appropriate network forming agent formulation for a particular grain technology and implementation. It was concluded that both TMP and BD have a major influence on the mechanical behaviour which allow obtaining a wide range of strength and elongation capabilities. The tensile strength increased by the excess of triol addition while the strain had a lowering effect which was compensated by the existence of diol extender. Tailoring the mechanical characteristics was easy to make by using a suitable proportions of TMP and BD to obtain outstanding mechanical properties for fixed NCO/OH, especially elastic capabilities, compared to polyurethanes formulated without any crosslinking additives.
Comparison of RBFs Interpolation for Load Transfer on Wing Structure
Authors: Cheng Pan , Zhao Yang , Sun Yuchen
Published: April 2021

Load transfer is of importance in simulation of aeroelasticity by coupling with CFD and FEM. Different RBFs (Radial Basis Function) with variant parameters are tested in load transfer and their results are compared in this paper. Result comparison shows that different RBFs with variant parameter will lead to different results. More approximate load on structure can be gained by MQB and TPS functions. The compact support RBFs should be used with wisely chosen support radius to gain approximate results.
Research on the Key Technology of Propulsion Drag System Division and Performance Analysis of Turboprop-powered Aircraft
Authors: Yiting Wu , Zhengzhong Yuan , Zhihang Cheng , Yang Tao
Published: April 2021

The remarkable characteristic of turboprop-powered aircraft is that its power system has great influence on the aerodynamic characteristics of the aircraft. Due to the action of turboprop slipstream, the airflow velocity after the propeller is obviously increased compared with the velocity of free flow. The turbulence caused by turboprop slipstream affects the aerodynamics of the aircraft, which in turn affects the performance of turboprop blades. In this paper, the layout characteristic and development trend of turboprop powered aircraft are briefly analysed. According to the characteristics of turboprop aircraft, a thrust/drag system division principle and interference characteristics treatment method for turboprop powered aircraft are introduced. Finally the influence of slipstream on a typical turboprop powered aircraft is analysed, It is very necessary to study the influence of propeller slipstream on aircraft aerodynamic performance in the early stage of developmental the effect of propeller slipstream on the aerodynamic characteristics of the whole aircraft is the strongest in take-off state, the influence of climbing state is weakened the influence of cruise state is the lease and the effect of slipstream effect increases with the increase of thrust.
The Problem of Elements Returning of Launch Vehicles and the Ways of Its Solution
Authors: Kretov A. , Mekhonoshin Yu. , Usmonov T.
Published: April 2021

The work, dedicated to the blessed memory of Vladimir Chizhukhin, deals with the problem of rescuing the blocks of carrier rockets for their subsequent use. The priority method is the use of aerospace parachute systems (ASPS), which are the lightest of all possible rescue systems. The possibility of using parachutes at space altitudes has been proven by the longterm practice of using them in M-100 meteorological rockets. Based on specific examples, numerical studies have been carried out on the possibility of using such a system, showing its great capabilities in combination with helicopter pick-up at the final stage of landing or with a rocket-dynamic soft-landing system.
A Pixelation Method for Loads Transfer on Fluid Structure Interface
Authors: Cheng Pan , Sun Yuchen , Zhao Yang , Ding Zekai , Zhang Wu
Published: April 2021

Fluid Structure Interaction (FSI) is widely applied in aircraft aerodynamic and aeroelastic analysis. Iteration between the CFD and FEA will solve the aerodynamic force, flow field, structure stress and deformation under equilibrium state simultaneously. In aircraft product development, the CFD mesh and Finite element model normally do not match each other because the goal of CFD and FEA are different. To connect between unmatched interface, a pixelation method is developed to transfer the aerodynamic loads onto the finite element model correctly. The pixelation method is also easy to be implemented and parallelized.
Direct Numerical Simulation of Particle-laden Flow Around an Obstacle at Different Reynolds Numbers
Authors: Lin Shengxiang , Xia Huanxiong , Zhang Zhenyu , Liu Jianhua , Wang Honglei
Published: April 2021

Inspired by the practical operation of the fluid machineries, direct numerical simulation of fluid with a lot of finite-size particles flowing around a large-size obstacle at three different Reynolds numbers is implemented by using a two-way coupled finite-volume, discrete-element and immersed-boundary method. The results show that, for a low Reynolds number Re=20, the flow is dominated by viscosity, and under the circumstances of a small Stokes number, the particles follow fluid streamlines closely. The flow suggests regular movement characteristics of laminar flow, although the vortices behind the obstacle tend to collapse under the perturbation of particles. For a moderate Reynolds number Re=100, the phenomenon of vortex shedding is also observed. Due to the centrifugal force induced by the vortices, particles are distributed around the main vortices behind the obstacle, forming particle-free zones in these vortices. For a high Reynolds number Re=300, the flow is chaotic. The vortices of many sizes appear irregularly in the domain and the distribution of particles tends to be uniform.
Analysis on technological features of pile foundations construction in frozen and seasonal thawing soils
Authors: Montayeva A , Zhussupbekov A , Kaliakin V N , Montayev S
Published: April 2021

This article assesses the more productive methods for thawing seasonally frozen soils. The most rational and progressive method of thawing seasonally frozen soils involves putting antifreeze additives into the soil. New goals and objectives for the development of pile foundation construction technology in seasonally frozen soils in northern and central regions of Kazakhstan is presented.
Characterization and assessment of crushed limestone powder and its environmental applications
Authors: Dafalla Muawia , Al-Mahbashi Ahmed , Alnuaim Ahmed
Published: April 2021

The subway (metro) and tunnel excavation works are of high demand in today’s large and urban cities. The use of tunnel boring machines resulted in huge quantities of crushed rock powder and generally treated as waste. This work is aimed at the characterization and assessment of Riyadh limestone powder and its possible use as a construction material. The environmental application of this powder as an additive to clay sand liners proved to be useful and efficient. Advanced testing indicated that this material can occupy part of the voids and help in reducing the high expansive nature of the liners and yet maintain a satisfactory hydraulic conductivity. Geotechnical characterization as well as SEM testing was performed. Soil water characteristic curves were established for selected mixtures. The introduction of this material was found environmentally friendly and can reduce the demand for bentonite and highly expansive additives.
The design of geotechnical structures using numerical methods
Authors: Jürgens H. , Henke S.
Published: April 2021

The use of numerical simulations in geotechnical engineering today is often limited to the investigation of the serviceability limit state (SLS). Therefore, the main focus up to now was more on the deformation prognosis for geotechnical constructions than the geotechnical design itself. Nevertheless, numerical methods like the Finite-Element-Method (FEM) for example can be a valuable tool to investigate the bearing capacity of geotechnical structures as well. E.g. existing structures which cannot be calculated using classical analytical approaches can be investigated with numerical simulations to estimate the remaining bearing capacity. In the present paper, the use of numerical methods for the design of geotechnical structures will be discussed. First, the approved ϕ - c reduction method is recalculated and verified with the help of a script based on the Python programming language. Afterwards, the Python script is extended so that the diameter of an Embedded Beam Row element can be successively reduced automatically similar to the ϕ - c reduction. Finally, a short outlook is given in which direction the research project should proceed.
California’s Mental Health Services Act and Mortality Due to Suicide, Homicide, and Acute Effects of Alcohol: A Synthetic Control Application
Authors: Zimmerman Scott C , Matthay Ellicott C , Rudolph Kara E , Goin Dana E , Farkas Kriszta , Rowe Christopher L , Ahern Jennifer
Published: April 2021

California’s Mental Health Services Act (MHSA) substantially expanded funding of county mental health services through a state tax, and led to broad prevention efforts and intensive services for individuals experiencing serious mental disorders. We estimated the associations between MHSA and mortality due to suicide, homicide, and acute effects of alcohol. Using annual cause-specific mortality data for each US state and the District of Columbia from 1976–2015, we used a generalization of the quasi-experimental synthetic control method to predict California’s mortality rate for each outcome in the absence of MHSA using a weighted combination of comparison states. We calculated the association between MHSA and each outcome as the absolute difference and percentage difference between California’s observed and predicted average annual rates over the postintervention years (2007–2015). MHSA was associated with modest decreases in average annual rates of homicide (−0.81/100,000 persons, corresponding to a 13% reduction) and mortality from acute alcohol effects (−0.35/100,000 persons, corresponding to a 12% reduction). Placebo test inference suggested that the associations were unlikely to be due to chance. MHSA was not associated with suicide. Protective associations with mortality due to homicide and acute alcohol effects provide evidence for modest health benefits of MHSA at the population level.
Network-based identification of key master regulators associated with an immune-silent cancer phenotype
Authors: Mall Raghvendra , Saad Mohamad , Roelands Jessica , Rinchai Darawan , Kunji Khalid , Almeer Hossam , Hendrickx Wouter , M Marincola Francesco , Ceccarelli Michele , Bedognetti Davide
Published: April 2021

A cancer immune phenotype characterized by an active T-helper 1 (Th1)/cytotoxic response is associated with responsiveness to immunotherapy and favorable prognosis across different tumors. However, in some cancers, such an intratumoral immune activation does not confer protection from progression or relapse. Defining mechanisms associated with immune evasion is imperative to refine stratification algorithms, to guide treatment decisions and to identify candidates for immune-targeted therapy. Molecular alterations governing mechanisms for immune exclusion are still largely unknown. The availability of large genomic datasets offers an opportunity to ascertain key determinants of differential intratumoral immune response. We follow a network-based protocol to identify transcription regulators (TRs) associated with poor immunologic antitumor activity. We use a consensus of four different pipelines consisting of two state-of-the-art gene regulatory network inference techniques, regularized gradient boosting machines and ARACNE to determine TR regulons, and three separate enrichment techniques, including fast gene set enrichment analysis, gene set variation analysis and virtual inference of protein activity by enriched regulon analysis to identify the most important TRs affecting immunologic antitumor activity. These TRs, referred to as master regulators (MRs), are unique to immune-silent and immune-active tumors, respectively. We validated the MRs coherently associated with the immune-silent phenotype across cancers in The Cancer Genome Atlas and a series of additional datasets in the Prediction of Clinical Outcomes from Genomic Profiles repository. A downstream analysis of MRs specific to the immune-silent phenotype resulted in the identification of several enriched candidate pathways, including NOTCH1, TGF-$\beta $, Interleukin-1 and TNF-$\alpha $ signaling pathways. TGFB1I1 emerged as one of the main negative immune modulators preventing the favorable effects of a Th1/cytotoxic response.
Biological Field Stations Promote Science Literacy through Outreach
Authors: Struminger Rhonda , Short Rachel A , Zarestky Jill , Vilen Lauren , Lawing A Michelle
Published: April 2021

Biological field stations (BFSs) are well positioned through their informal STEM (science, technology, engineering, and mathematics) education programs to improve levels of science literacy and support environmental sustainability. A survey of 223 US BFSs revealed that their outreach programs strive to promote conservation and environmental stewardship in addition to disseminating place-based knowledge and/or skills. In this article, we unpack the educational approaches that BFSs use to engage learners, the aspects of science literacy most often addressed, and the perceived learning outcomes. Most notably, the BFSs reported that their participants develop an interest in and excitement for science, increase or change their knowledge of program topics, identify more with the scientific enterprise, and engage in scientific practices. The results indicate opportunities for BFSs to conduct more rigorous assessments of participant learning and program impact. By focusing on learner engagement, science learning, and participant outcomes, BFSs and other place-based informal education venues can expand their efforts and better support conservation and science learning.
Severe Acute Respiratory Syndrome Coronavirus 2 Transmission in Intercollegiate Athletics Not Fully Mitigated With Daily Antigen Testing
Authors: Moreno Gage K , Braun Katarina M , Pray Ian W , Segaloff Hannah E , Lim Ailam , Poulsen Keith , Meiman Jonathan , Borcher James , Westergaard Ryan P , Moll Michael K , Friedrich Thomas C , O’Connor David H
Published: April 2021

Background

High-frequency, rapid-turnaround severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) testing continues to be proposed as a way of efficiently identifying and mitigating transmission in congregate settings. However, 2 SARS-CoV-2 outbreaks occurred among intercollegiate university athletic programs during the fall 2020 semester, despite mandatory directly observed daily antigen testing.

Methods

During the fall 2020 semester, athletes and staff in both programs were tested daily using Quidel’s Sofia SARS Antigen Fluorescent Immunoassay, with positive antigen results requiring confirmatory testing with real-time reverse-transcription polymerase chain reaction. We used genomic sequencing to investigate transmission dynamics in these 2 outbreaks.

Results

In the first outbreak, 32 confirmed cases occurred within a university athletics program after the index patient attended a meeting while infectious, despite a negative antigen test on the day of the meeting. Among isolates sequenced from that outbreak, 24 (92%) of 26 were closely related, suggesting sustained transmission following an initial introduction event. In the second outbreak, 12 confirmed cases occurred among athletes from 2 university programs that faced each other in an athletic competition, despite receipt of negative antigen test results on the day of the competition. Sequences from both teams were closely related and distinct from viruses circulating in the community for team 1, suggesting transmission during intercollegiate competition in the community for team 2.

Conclusions

These findings suggest that antigen testing alone, even when mandated and directly observed, may not be sufficient as an intervention to prevent SARS-CoV-2 outbreaks in congregate settings, and they highlight the importance of vaccination to prevent SARS-CoV-2 outbreak in congregate settings.
The role of cation diffusion facilitator CDF-1 in lipid metabolism in Caenorhabditis elegans
Authors: Hu Ying , Wang Yanli , Wang Xuanjun , Wu Xiaoyun , Fu Lin , Liu Xiayu , Wen Yu , Sheng Jun , Zhang Jingjing
Published: April 2021

Zinc is one of the most important trace elements as it plays a vital role in many biological processes. As well, aberrant zinc metabolism has been implicated in lipid-related metabolic diseases. Previously, we showed that zinc antagonizes iron to regulate sterol regulatory element-binding proteins and the stearoyl-CoA desaturase (SREBP-SCD) pathway in lipid metabolism in the model organism Caenorhabditis elegans. In this study, we present the identification of another cation diffusion facilitator, CDF-1, which regulates lipid metabolism along with SUR-7 in response to zinc. Inactivation of SBP-1, the only homolog of SREBPs, leads to an increased zinc level but decreased lipid accumulation. However, either the cdf-1(n2527) or sur-7(tm6523) mutation could successfully restore the altered fatty acid profile, fat content, and zinc level of the sbp-1(ep79) mutant. Furthermore, we found that CDF-1/SUR-7 may functionally bypass SBP-1 to directly affect the conversion activity of SCD in the biosynthesis of unsaturated fatty acids and lipid accumulation. Collectively, these results consistently support the link between zinc homeostasis and lipid metabolism via the SREBP-SCD axis by the cation diffusion facilitators CDF-1 and SUR-7.
Caenorhabditis elegansjunctophilin has tissue-specific functions and regulates neurotransmission with extended-synaptotagmin
Authors: Piggott Christopher A , Wu Zilu , Nurrish Stephen , Xu Suhong , Kaplan Joshua M , Chisholm Andrew D , Jin Yishi
Published: April 2021

The junctophilin family of proteins tether together plasma membrane (PM) and endoplasmic reticulum (ER) membranes, and couple PM- and ER-localized calcium channels. Understanding in vivo functions of junctophilins is of great interest for dissecting the physiological roles of ER-PM contact sites. Here, we show that the sole Caenorhabditis elegans junctophilin JPH-1 localizes to discrete membrane contact sites in neurons and muscles and has important tissue-specific functions. jph-1 null mutants display slow growth and development due to weaker contraction of pharyngeal muscles, leading to reduced feeding. In the body wall muscle, JPH-1 colocalizes with the PM-localized EGL-19 voltage-gated calcium channel and ER-localized UNC-68 RyR calcium channel, and is required for animal movement. In neurons, JPH-1 colocalizes with the membrane contact site protein Extended-SYnaptoTagmin 2 (ESYT-2) in the soma, and is present near presynaptic release sites. Interestingly, jph-1 and esyt-2 null mutants display mutual suppression in their response to aldicarb, suggesting that JPH-1 and ESYT-2 have antagonistic roles in neuromuscular synaptic transmission. Additionally, we find an unexpected cell nonautonomous effect of jph-1 in axon regrowth after injury. Genetic double mutant analysis suggests that jph-1 functions in overlapping pathways with two PM-localized voltage-gated calcium channels, egl-19 and unc-2, and with unc-68 for animal health and development. Finally, we show that jph-1 regulates the colocalization of EGL-19 and UNC-68 and that unc-68 is required for JPH-1 localization to ER-PM puncta. Our data demonstrate important roles for junctophilin in cellular physiology, and also provide insights into how junctophilin functions together with other calcium channels in vivo.
A chromosome-level reference genome of the hazelnut, Corylus heterophylla Fisch
Authors: Zhao Tiantian , Ma Wenxu , Yang Zhen , Liang Lisong , Chen Xin , Wang Guixi , Ma Qinghua , Wang Lujun
Published: April 2021

Background

Corylus heterophylla Fisch. is a species of the Betulaceae family native to China. As an economically and ecologically important nut tree, C. heterophylla can survive in extremely low temperatures (–30 to –40 °C). To deepen our knowledge of the Betulaceae species and facilitate the use of C. heterophylla for breeding and its genetic improvement, we have sequenced the whole genome of C. heterophylla.

Findings

Based on >64.99 Gb (∼175.30×) of Nanopore long reads, we assembled a 370.75-Mb C. heterophylla genome with contig N50 and scaffold N50 sizes of 2.07 and 31.33  Mb, respectively, accounting for 99.23% of the estimated genome size (373.61 Mb). Furthermore, 361.90 Mb contigs were anchored to 11 chromosomes using Hi-C link data, representing 97.61% of the assembled genome sequences. Transcriptomes representing 4 different tissues were sequenced to assist protein-coding gene prediction. A total of 27,591 protein-coding genes were identified, of which 92.02% (25,389) were functionally annotated. The phylogenetic analysis showed that C. heterophylla is close to Ostrya japonica, and they diverged from their common ancestor ∼52.79 million years ago.

Conclusions

We generated a high-quality chromosome-level genome of C. heterophylla. This genome resource will promote research on the molecular mechanisms of how the hazelnut responds to environmental stresses and serves as an important resource for genome-assisted improvement in cold and drought resistance of the Corylus genus.
Adjoint slip inversion under a constrained optimization framework: revisiting the 2006 Guerrero slow slip event
Authors: Tago J , Cruz-Atienza V M , Villafuerte C , Nishimura T , Kostoglodov V , Real J , Ito Y
Published: April 2021

To shed light on the prevalently slow, aseismic slip interaction between tectonic plates, we developed a new static slip inversion strategy, the ELADIN (ELastostatic ADjoint INversion) method, that uses the adjoint elastostatic equations to compute the gradient of the cost function. ELADIN is a 2-step inversion algorithm to efficiently handle plausible slip constraints. First it finds the slip that best explains the data without any constraint, and then refines the solution by imposing the constraints through a Gradient Projection Method. To obtain a self-similar, physically consistent slip distribution that accounts for sparsity and uncertainty in the data, ELADIN reduces the model space by using a von Karman regularization function that controls the wavenumber content of the solution, and weights the observations according to their covariance using the data precision matrix. Since crustal deformation is the result of different concomitant interactions at the plate interface, ELADIN simultaneously determines the regions of the interface subject to both stressing (i.e. coupling) and relaxing slip regimes. For estimating the resolution, we introduce a mobile checkerboard analysis that allows to determine lower-bound fault resolution zones for an expected slip-patch size and a given stations array. We systematically test ELADIN with synthetic inversions along the whole Mexican subduction zone and use it to invert the 2006 Guerrero Slow Slip Event (SSE), which is one of the most studied SSEs in Mexico. Since only 12 GPS stations recorded the event, careful regularization is thus required to achieve reliable solutions. We compared our preferred slip solution with two previously published models and found that our solution retains their most reliable features. In addition, although all three SSE models predict an upward slip penetration invading the seismogenic zone of the Guerrero seismic gap, our resolution analysis indicates that this penetration might not be a reliable feature of the 2006 SSE.
Changes in infection-related hospitalizations in children following pandemic restrictions: an interrupted time-series analysis of total population data
Authors: Todd Isobel M F , Miller Jessica E , Rowe Stacey L , Burgner David P , Sullivan Sheena G
Published: April 2021

Background

Infectious diseases are a leading cause of hospitalization during childhood. The various mitigation strategies implemented to control the coronavirus disease (COVID-19) pandemic could have additional, unintended benefits for limiting the spread of other infectious diseases and their associated burden on the health care system.

Methods

We conducted an interrupted time-series analysis using population-wide hospitalization data for the state of Victoria, Australia. Infection-related hospitalizations for children and adolescents (aged <18 years, total source population ∼1.4 million) were extracted using pre-defined International Classification of Diseases 10th Revision Australian Modification (ICD-10-AM) codes. The change in weekly hospitalization rates (incidence rate ratio, IRR) for all infections following the introduction of pandemic-related restrictions from 15 March 2020 was estimated.

Results

Over 2015–19, the mean annual incidence of hospitalization with infection among children less than 18 years was 37 per 1000 population. There was an estimated 65% (95% CI 62-67%) reduction in the incidence of overall infection-related hospitalizations associated with the introduction of pandemic restrictions. The reduction was most marked in younger children (at least 66% in those less than 5 years of age) and for lower respiratory tract infections (relative reduction 85%, 95% CI 85-86%).

Conclusions

The wider impacts of pandemic mitigation strategies on non-COVID-19 infection-related hospitalizations are poorly understood. We observed marked and rapid decreases in hospitalized childhood infection. In tandem with broader consequences, sustainable measures, such as improved hand hygiene, could reduce the burden of severe childhood infection post-pandemic and the social and economic costs of hospitalization.
A structured model for COVID-19 spread: modelling age and healthcare inequities
Authors: James A , Plank M J , Binny R N , Lustig A , Hannah K , Hendy S C , Steyn N
Published: April 2021

We use a stochastic branching process model, structured by age and level of healthcare access, to look at the heterogeneous spread of COVID-19 within a population. We examine the effect of control scenarios targeted at particular groups, such as school closures or social distancing by older people. Although we currently lack detailed empirical data about contact and infection rates between age groups and groups with different levels of healthcare access within New Zealand, these scenarios illustrate how such evidence could be used to inform specific interventions. We find that an increase in the transmission rates among children from reopening schools is unlikely to significantly increase the number of cases, unless this is accompanied by a change in adult behaviour. We also find that there is a risk of undetected outbreaks occurring in communities that have low access to healthcare and that are socially isolated from more privileged communities. The greater the degree of inequity and extent of social segregation, the longer it will take before any outbreaks are detected. A well-established evidence for health inequities, particularly in accessing primary healthcare and testing, indicates that Māori and Pacific peoples are at a higher risk of undetected outbreaks in Aotearoa New Zealand. This highlights the importance of ensuring that community needs for access to healthcare, including early proactive testing, rapid contact tracing and the ability to isolate, are being met equitably. Finally, these scenarios illustrate how information concerning contact and infection rates across different demographic groups may be useful in informing specific policy interventions.
Single-Laboratory Validation of an Immunoaffinity Column Cleanup LC Method for the Analysis of Aflatoxins and Ochratoxin A in Cannabis Plant Material, Resins, Vapes, Isolates, and Edible Products
Authors: Greaves Alana , Maddison Kyle , Doran Marney , Lin Sarah , Geiling Ben
Published: April 2021

Background

Potential fungal infection of cannabis plants during drying has raised concerns of resulting mycotoxin contamination in leaves and flowers and subsequent contamination of derived products including cannabis-containing edible products. Validated routine methods are essential to monitor cannabis and cannabis products to ensure consumer safety consistent with long-standing controls for mycotoxins such as aflatoxins and ochratoxin A in foodstuffs.

Objective

To provide single-laboratory validation data to demonstrate the suitability of a method for determining aflatoxins and ochratoxin A in cannabis plant material, resins, vapes, isolates, and edible products such as chocolate.

Method

Extraction of solid and liquid matrixes with acetonitrile:water, centrifugation, and then dilution of an aliquot of supernatant with phosphate-buffered saline solution containing Tween 20 surfactant. Cleanup by passing through an immunoaffinity column containing antibodies to both aflatoxins and ochratoxin A and analyzing in a single LC chromatographic run with fluorescence detection.

Results

For within-day analysis, recoveries were in the range 77 to 99% with RSDs from 0.7 to 9.6% for aflatoxin B1. Similarly, ochratoxin A recoveries were from 64 to 94% and RSDs from 0.9 to 9.5% for mycotoxin mixtures spiked into cannabis flowers, resins, vapes, isolates, chocolate, gummies, edible oils, and beverages.

Conclusions

A method for the determination of aflatoxins and ochratoxin A was successfully developed and single-laboratory validation data has been presented for cannabis plant material, resins, vapes, isolates, and edible products.

Highlights

A multi-mycotoxin immunoaffinity column cleanup with LC-fluorescence has been validated and shown to be suitable for routine control of aflatoxins and ochratoxin A in cannabis flowers and a diverse range of edible cannabis products.
Digging roots is easier with AI
Authors: Han Eusun , Smith Abraham George , Kemper Roman , White Rosemary , Kirkegaard John A , Thorup-Kristensen Kristian , Athmann Miriam
Published: April 2021

The scale of root quantification in research is often limited by the time required for sampling, measurement, and processing samples. Recent developments in convolutional neural networks (CNNs) have made faster and more accurate plant image analysis possible, which may significantly reduce the time required for root measurement, but challenges remain in making these methods accessible to researchers without an in-depth knowledge of machine learning. We analyzed root images acquired from three destructive root samplings using the RootPainter CNN software that features an interface for corrective annotation for easier use. Root scans with and without non-root debris were used to test if training a model (i.e. learning from labeled examples) can effectively exclude the debris by comparing the end results with measurements from clean images. Root images acquired from soil profile walls and the cross-section of soil cores were also used for training, and the derived measurements were compared with manual measurements. After 200 min of training on each dataset, significant relationships between manual measurements and RootPainter-derived data were noted for monolith (R2=0.99), profile wall (R2=0.76), and core-break (R2=0.57). The rooting density derived from images with debris was not significantly different from that derived from clean images after processing with RootPainter. Rooting density was also successfully calculated from both profile wall and soil core images, and in each case the gradient of root density with depth was not significantly different from manual counts. Differences in root-length density (RLD) between crops with contrasting root systems were captured using automatic segmentation at soil profiles with high RLD (1–5 cm cm–3) as well with low RLD (0.1–0.3 cm cm–3). Our results demonstrate that the proposed approach using CNN can lead to substantial reductions in root sample processing workloads, increasing the potential scale of future root investigations.
The binary star θ1 Ori C: orbital elements, evolutionary parameters and chemical composition
Authors: Rzaev Abid Kh , Shimansky V V , Kolbin A I
Published: April 2021

About 200 echelle spectra, obtained at the 1-m and 6-m telescopes of the Special Astrophysical Observatory (SAO) of the Russian Academy of Sciences (RAS), with high spectral resolution and signal-to-noise ratio, were used to investigate the radial velocity variability with time in both components of the θ1 Ori C binary system during its periastron passage. The quality of our spectra have allowed us to find a methodical approach for the spectroscopic study of the orbital motions of both components and to select lines suitable for this goal. The analysis has shown that the He ii λ 4541, 5411 lines are suitable for the primary component, and the Si iii λ 4552 line is suitable for the secondary component. Radial velocities thus measured for both components from the spectra obtained over 20 yr, along with the interferometric observations of the relative positions of the components, were used to construct a combined three-dimensional orbit of the system, in order to derive its reliable orbital parameters. Orbital elements were determined with good accuracy. For the dynamical distance, we have found a value of about d = 415 ± 6 pc, and for the system mass we find $M_{\rm sys}=44.8\pm 4.5\, {\rm M}_\odot$. We apply a special method to calculate the synthetic spectra in binaries, taking into account the contribution of both components in their radiation, for the theoretical analysis of the observable spectra of θ1 Ori C. Atmospheric parameters are refined for the primary, and are determined for the secondary component for the first time. The chemical composition of θ1 Ori C is determined, which coincides with the chemical composition of its surrounding nebula.
BENZ WS: the Bologna ENZyme Web Server for four-level EC number annotation
Authors: Baldazzi Davide , Savojardo Castrense , Martelli Pier Luigi , Casadio Rita
Published: April 2021

The Bologna ENZyme Web Server (BENZ WS) annotates four-level Enzyme Commission numbers (EC numbers) as defined by the International Union of Biochemistry and Molecular Biology (IUBMB). BENZ WS filters a target sequence with a combined system of Hidden Markov Models, modelling protein sequences annotated with the same molecular function, and Pfams, carrying along conserved protein domains. BENZ returns, when successful, for any enzyme target sequence an associated four-level EC number. Our system can annotate both monofunctional and polyfunctional enzymes, and it can be a valuable resource for sequence functional annotation.
The three-way junction structure of the HIV-1 PBS-segment binds host enzyme important for viral infectivity
Authors: Song Zhenwei , Gremminger Thomas , Singh Gatikrushna , Cheng Yi , Li Jun , Qiu Liming , Ji Juan , Lange Margaret J , Zuo Xiaobing , Chen Shi-Jie , Zou Xiaoqin , Boris-Lawrie Kathleen , Heng Xiao
Published: April 2021

HIV-1 reverse transcription initiates at the primer binding site (PBS) in the viral genomic RNA (gRNA). Although the structure of the PBS-segment undergoes substantial rearrangement upon tRNALys3 annealing, the proper folding of the PBS-segment during gRNA packaging is important as it ensures loading of beneficial host factors. DHX9/RNA helicase A (RHA) is recruited to gRNA to enhance the processivity of reverse transcriptase. Because the molecular details of the interactions have yet to be defined, we solved the solution structure of the PBS-segment preferentially bound by RHA. Evidence is provided that PBS-segment adopts a previously undefined adenosine-rich three-way junction structure encompassing the primer activation stem (PAS), tRNA-like element (TLE) and tRNA annealing arm. Disruption of the PBS-segment three-way junction structure diminished reverse transcription products and led to reduced viral infectivity. Because of the existence of the tRNA annealing arm, the TLE and PAS form a bent helical structure that undergoes shape-dependent recognition by RHA double-stranded RNA binding domain 1 (dsRBD1). Mutagenesis and phylogenetic analyses provide evidence for conservation of the PBS-segment three-way junction structure that is preferentially bound by RHA in support of efficient reverse transcription, the hallmark step of HIV-1 replication.
High Likelihood of Accepting COVID-19 Vaccine in a Latinx Community at High SARS-CoV-2 Risk in San Francisco
Authors: Peng James , Marquez Carina , Rubio Luis , Chamie Gabriel , Jones Diane , Jacobo Jon , Rojas Susana , Rojas Susy , Tulier-Laiwa Valerie , Black Douglas , Martinez Jackie , Pilarowski Genay , Cox Chesa , Derisi Joe , Havlir Diane , Petersen Maya
Published: April 2021

Of 4133 persons surveyed at a low-barrier coronavirus disease 2019 (COVID-19) test site with high positivity in an urban Latinx community in January 2021, 86% indicated that they would accept a COVID-19 vaccination. The top reasons for vaccine hesitancy included concerns around side effects and safety and distrust of health care systems.
Nambu brackets, Chern–Simons theories, quantum curves and M2-branes
Authors: Moriyama Sanefumi
Published: April 2021

A non-technical review on recent progress in M2-branes is given. We focus especially on (1) historical progress in searching for the worldvolume theory of M2-branes using Nambu brackets and supersymmetric Chern–Simons theories, (2) studies of the ABJM matrix model obtained from localization using various techniques and (3) new insights of quantum curves derived from the studies of the ABJM matrix model.
Case Report of Two Patients With COVID-19 and Sacral Pressure Injuries Associated with Pyoderma Gangrenosum
Authors: Elkhatib Rania , Giunta Gabriele , Hanssens Valerie , Kapila Ayush , De Baerdemaeker Randy , Zeltzer Assaf , Hamdi Moustapha
Published: April 2021

During the COVID-19 pandemic, an increasing number of patients have been admitted to the ICU with severe respiratory complications requiring prolonged supine positioning. Recently, many case reports have been published regarding dermatologic manifestations associated with COVID-19. However, there is little information about the clinical features of these manifestations. Pyoderma gangrenosum (PG) is an ulcerative noninfectious inflammatory disease of the skin. In at least 50% of the cases, the etiology is unknown. Nevertheless, PG is associated with many systemic diseases. In this article, the authors report two critically ill patients with COVID-19 who developed sacral ulcers during their recovery in the ICU. These ulcers had an atypical course and were exacerbated by surgical debridements. Accordingly, providers suspected PG, which was confirmed by the clinical evolution of the ulcers and biopsies taken from the wounds. To the best of the authors’ knowledge, no previous articles have reported sacral pressure injuries associated with PG in patients with COVID-19. Providers should suspect PG in patients with COVID-19 who develop nonhealing pressure injuries.
PAs in the National Guard and Reserves
Authors: Hooker Roderick S. , Kozikowski Andrzej , Paul Johnny
Published: April 2021

The role of physician assistants (PAs) in the United States extends to the Army National Guard; Air National Guard; and reserves of the Army, Navy, Air Force, and Coast Guard (collectively known as reserve components). To understand the duality of civilian-military PA roles, a census of the armed forces was undertaken, drawing on knowledgeable senior PA medical officers in each of the services. The survey was supplemented with data from the National Commission on Certification of Physician Assistants. In 2020, there were 1,944 PAs in the five military reserve components with the majority (1,597) in the Army. Most National Guard, Air National Guard, and Reserve PAs fill medical officer roles, drill with units, and are subject to active duty. As soldiers, sailors, and airmen, military PAs are trained in health, safety, warfare readiness, casualty, trauma, and crisis response. The tenure of a reserve component PA in the military ranged between 10.2 and 17.8 years. In their civilian roles, most PAs are licensed and clinically active—the majority report they work in family/general medicine, emergency medicine, general surgery, or orthopedic medicine and surgery. This dual-career role and responsibility suggests the utility and flexibility of the PA is broader than previously reported. The findings set the stage for additional research on healthcare professionals during times of domestic and international emergencies.
The Future of Nursing 2020-2030
Authors: Hassmiller Susan B.
Published: April 2021

Charting a path to achieve health equity.
Management of maternal COVID-19: considerations for anesthesiologists
Authors: Bernstein Kyra , Landau Ruth
Published: April 2021

Purpose of review

To describe updates to pragmatic recommendations that were published during the first coronavirus disease 2019 (COVID-19) surge, including the current thinking about whether pregnancy worsens the severity of COVID-19.

Recent findings

Although a majority of pregnant women infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remain asymptomatic or paucisymptomatic, pregnancy puts women at higher risk of severe COVID-19 and adverse birth outcomes. Pregnant and recently pregnant women are more likely to be admitted to intensive care units and receive mechanical ventilation than nonpregnant patients with COVID-19, although preexisting maternal comorbidities are significant risk factors.

Early provision of neuraxial labor analgesia with a functional indwelling epidural catheter has been universally promoted, with the goal to reduce avoidable general anesthesia for cesarean delivery and mitigate risks for healthcare workers during airway manipulation. This recommendation, along with updated workflow models of anesthesia coverage, may contribute to a reduction in general anesthesia rates.

Initial recommendations to provide early neuraxial labor analgesia and avoid general anesthesia for cesarean delivery have not changed over time. Although workflows have significantly changed to allow continued patient and healthcare workers’ safety, clinical anesthesia protocols for labor and delivery are essentially the same.
Rethinking Home-based Outpatient Parenteral Antibiotic Therapy for Persons Who Inject Drugs: An Opportunity for Change in the Time of COVID-19
Authors: Jawa Raagini , Rozansky Hallie , Clemens Dylan , Fagan Maura , Walley Alexander Y.
Published: April 2021

Outpatient parenteral antibiotic therapy (OPAT) refers to the monitored provision of intravenous antibiotics for complicated infections outside of a hospital setting, typically in a rehabilitation facility, an infusion center, or the home. Home-based OPAT allows for safe completion of prolonged courses of therapy while decreasing costs to the healthcare system, minimizing the risk of hospital-related infectious exposures for patients, and permitting patients to recover in a familiar environment. Amidst the COVID-19 pandemic, during which nursing facilities have been at the center of many outbreaks of the SARS-CoV-2 virus, completion of antimicrobial therapy in the home is an even more appealing option. Persons who inject drugs (PWID) frequently present with infectious complications of their injection drug use which require long courses of parenteral therapy. However, these individuals are frequently excluded from home-based OPAT on the basis of their addiction history. This commentary describes perceived challenges to establishing home-based OPAT for PWID, discusses ways in which this is discriminatory and unsupported by available data, highlights ways in which the COVID-19 pandemic has accentuated inequities in care, and proposes a multidisciplinary approach championed by Addiction specialists to increasing implementation of OPAT for appropriate patients with substance use disorders.
Effectiveness of Acceptance and Commitment Therapy on Reducing Body Image Disorders in Adolescent Girls
Authors: Rezaeisharif Ali , Cheraghian Hadis , Naeim Mahdi
Published: April 2021

Background:

Body image dissatisfaction and weight self-stigma are prevalent and are associated with physical and psychological ill-health. Acceptance and commitment therapy is increasingly used for both, yet little is known about its effectiveness.

Objectives:

This study aimed to determine the efficacy of acceptance and commitment therapy in reducing the body image disorder in adolescent girls.

Methods:

This study was quasi-experimental with pretest and posttest design with the control group. The statistical population of the study was all high school female adolescents with body image disorder; 280 girls were selected based on available sampling from 3 high schools in Ardabil City. Multidimensional Body-Self Relations Questionnaire (MBSRQ) scales were used to assess body image disorder and data were analyzed by SPSS software, version 19.

Results:

The results of this study indicated that this treatment was effective in reducing body image disorder in adolescent girls.

Conclusions:

Therefore, this treatment is suggested to reduce body image disorder in adolescent girls.