bluuebunny/crossref_metadata_2025 huggingface dataset:
Transmission characteristics of electromagnetic waves in 2D tunable plasma photonic crystals
Authors: Liang Yichao , Liu Zhen , Lin Liguang , Peng Jun , Liu Rubing , Lin Qi
Published: February 2021

The transmission characteristics of electromagnetic waves in a 2D plasma photonic crystal (PPC) in the frequency range of 1–12 GHz are investigated by experiments and numerical simulations. For PPC composed of discharge plasma tubes, the transmission characteristics of electromagnetic waves in PPC can be adjusted by changing the discharge current. The transmission characteristics of PPC in different array arrangements and working modes are obtained experimentally; the finite difference time domain (FDTD) method is used to obtain the band structure of PPC in different array arrangements and working modes. The results show the following: the simulation results of the layered model are close to the experimental results; whether the discharge plasma tube is working or not has an important influence on the transmission characteristics of PPC; and Bragg scattering and the localized surface plasmons (LSPs) are the main reasons for the generation of the bandgap. The increase in electron density causes the bandgap to move to higher frequencies and increases the number of bandgaps. The research results can be used as a reference for the evaluation of electromagnetic properties of 2D PPCs and the design of new devices such as plasma antennas.
Optical 1-bit comparator based on two-dimensional photonic crystals
Authors: Parandin Fariborz , Kamarian Reza , Jomour Mohamadreza
Published: February 2021

A comparator is one of the important combinational logic circuits. An optical comparator was designed and simulated based on photonic crystals. Point and linear defects were also used in the proposed optical comparator. The use of simple defect paths and the absence of ring resonators reduced the complexity of the structure. One of the characteristics of the proposed structure is that it has a very small size, which leads to the suitability of this comparator for optical integrated circuits. Another characteristic of this comparator is an increase in the optical power difference for the logical values “0” and “1,” which reduces the bit detection error in the output. This comparator is also designed to operate on the 1.55 µm wavelength, and it can be used in today’s optical telecommunication circuits.
Range-intensity-profile prior dehazing method for underwater range-gated imaging
Authors: Wang Minmin , Wang Xinwei , Zhang Yue , Sun Liang , Lei Pingshun , Yang Yuqing , Chen Jianan , He Jun , Zhou Yan
Published: February 2021

This paper is concerned with the mitigation of backscatter effects in a single gated image. A range-intensity-profile prior dehazing method is proposed to estimate scene depth and finely remove water backscatter at different depths for underwater range-gated imaging. It is based on the prior that the target intensity is distributed with range intensity profiles in gated images. The depth transmission and depth-noise map are then calculated from the scene depth. A high-quality image is restored by subtracting the depth-noise map and dividing the depth transmission. The simulation and experimental results show that the proposed method works well even if a portion of the estimated depth may be smaller than its real value, and the peak signal-to-noise ratio of dehazing images gets up to a doubled increase.
Interaction between sampled rays’ defocusing and number on accommodative response in integral imaging near-eye light field displays
Authors: Qin Zong , Zhang Yuhan , Yang Bo-Ru
Published: February 2021

In an integral imaging near-eye light field display using a microlens array, a point on a reconstructed depth plane (RDP) is reconstructed by sampled rays. Previous studies respectively suggested the accommodative response may shift from the RDP under two circumstances: (i) the RDP is away from the central depth plane (CDP) to introduce defocusing in sampled rays; (ii) the sampled ray number is too low. However, sampled rays’ defocusing and number may interact, and the interaction’s influence on the accommodative response has been little revealed. Therefore, this study adopts a proven imaging model providing retinal images to analyze the accommodative response. As a result, when the RDP and the CDP coincide, the accommodative response matches the RDP. When the RDP deviates from the CDP, defocusing is introduced in sampled rays, causing the accommodative response to shift from the RDP towards the CDP. For example, in a system with a CDP of 4 diopters (D) and 45 sampled rays, when the RDP is at 3, 2, 1, and 0 D, the accommodative response shifts to 3.25, 2.75, 2, and 1.75 D, respectively. With fewer rays, the accommodative response tends to further shift to the CDP. Eventually, with fewer than five rays, the eye accommodates to the CDP and loses the 3D display capacity. Moreover, under different RDPs, the ray number influences differently, and vice versa. An x-y polynomial equation containing three interactive terms is finally provided to reveal the interaction between RDP position and ray number. In comparison, in a pinhole-based system with no CDP, the accommodative response always matches the RDP when the sampled ray number is greater than five.
Angle-insensitive plasmonic nanorod metamaterial-based band-pass optical filters
Authors: Wells Brian M. , Lotti Francesco , Nasir Mazhar E. , Zayats Anatoly V. , Podolskiy Viktor A.
Published: February 2021

We demonstrate, experimentally and theoretically, a new class of angle-insensitive band-pass optical filters that utilize anisotropy of plasmonic nanorod metamaterials, in both ε ≃ −1 and epsilon-near-infinity regimes, to minimize dependence of optical path on the incident angle. The operating wavelength and bandwidth of the filter can be engineered by controlling the geometry of the metamaterial. Experimental results are in agreement with full wave numerical and analytical solutions of the Maxwell's equations. Theoretical simulations show that performance of the systems can be further improved by replacing metallic mirrors with dielectric stacks.
Accelerating ptychographic reconstructions using spectral initializations
Authors: Valzania Lorenzo , Dong Jonathan , Gigan Sylvain
Published: February 2021

Ptychography is a promising phase retrieval technique for label-free quantitative phase imaging. Recent advances in phase retrieval algorithms witnessed the development of spectral methods to accelerate gradient descent algorithms. Using spectral initializations on experimental data, for the first time, we report three times faster ptychographic reconstructions than with a standard gradient descent algorithm and improved resilience to noise. Coming at no additional computational cost compared to gradient-descent-based algorithms, spectral methods have the potential to be implemented in large-scale iterative ptychographic algorithms.
On-chip optical true time delay lines based on subwavelength grating waveguides
Authors: Wang Yue , Sun Hao , Khalil Mostafa , Dong Wei , Gasulla Ivana , Capmany José , Chen Lawrence R.
Published: February 2021

An optical true time delay line (OTTDL) is a fundamental building block for signal processing applications in microwave photonics and optical communications. Here, we experimentally demonstrate an index-variable OTTDL based on an array of 40 subwavelength grating (SWG) waveguides in silicon-on-insulator. Each SWG waveguide in the array is 34 mm long and arranged in a serpentine manner; the average incremental delay between waveguides is about 4.7 ps, and the total delay between the first and last waveguides is approximately 181.9 ps. The waveguide array occupies a chip area of

∼

6.5

m
m

×

8.7

m
m

=

56.55

m
m

2

. The proposed OTTDLs bring potential advantages in terms of compactness as well as operation versatility to a variety of microwave signal processing applications.
Resolution improvement of dark-field microscopy via microparticle near-field illumination
Authors: Ling Jinzhong , Wang Yucheng , Liu Xin , Wang Xiaorui
Published: February 2021

In this Letter, a novel, to the best of our knowledge, approach to improve the imaging resolution of dark-field microscopy is proposed and demonstrated. Inspired by an existing super-resolution imaging method based on near-filed illumination using a prism or microfiber, a microparticle-generated full-direction evanescent field for sample illumination was demonstrated to achieve a multi-orientation near-field illumination in one snapshot and to obtain a super-resolution image by spatial frequency shifting. The ultimate resolution and the additional magnification factor of this method were analyzed theoretically. Imaging experiments were carried on a standard microscope calibration target MetroChip and a Blu-ray disc characterized by subwavelength microstructures. High-imaging resolution was demonstrated experimentally, and two novel illumination modes were proposed to overcome imaging direction selectivity. Our work opened up a new perspective of super-resolution imaging with near-field illumination.
Micro-electromechanical-system-tuned resonant filters spanning the 8–12  µm band
Authors: Ko Y. H. , Lee K. J. , Das S. , Gupta N. , Magnusson R.
Published: February 2021

The spectral band covering

∼

8

−

12

µ

m

is atmospherically transparent and therefore important for terrestrial imaging, day/night situational awareness systems, and spectroscopic applications. There is a dearth of tunable filters spanning the band. Here, we propose and demonstrate a new, to the best of our knowledge, tunable-filter method engaging the fundamental physics of the guided-mode resonance (GMR) effect realized with a non-periodic lattice. The polarization-dependent filter is fashioned with a one-dimensional Ge grating on a ZnSe substrate and interrogated with a

∼

1.5

m
m

Gaussian beam to show clear transmittance nulls. To expand the tuning range, the device parameters are optimized for sequential operation in TM and TE polarization states. The theoretical model exhibits a tunable range exceeding 4 µm, thus covering the band fully. In the experiment, a prototype device exhibits a spectral range of 8.6–10.0 µm in TM and 9.9–11.7 µm in TE polarization or

>

3

µ

m

total. With additional efforts in fabrication, we expect to achieve the full range.
800  Gb/s/200  m FSO link with a WDM-PAM4 scheme and SLM-based beam tracking technology
Authors: Lu Hai-Han , Huang Xu-Hong , Tsai Wen-Shing , Feng Chao-Yu , Chou Cing-Ru , Chen Yi-Hao , Huang Yu-Ting , Nainggolan Agustina
Published: February 2021

An 800 Gb/s/200 m free-space optical (FSO) link with a wavelength-division multiplexing (WDM)-four-level pulse amplitude modulation (PAM4) scheme and spatial light modulator (SLM)-based beam tracking technology is constructed. To the best of our knowledge, this is the first one that adopts a WDM-PAM4 scheme and an SLM-based beam tracking technology to simultaneously afford a high transmission capacity of 800 Gb/s and resolve the laser beam misalignment problem due to target device movement. By adopting a 16-wavelength WDM-PAM4 scheme, the transmission capacity of the FSO link is considerably enhanced with an 800 Gb/s (

50

G
b

/

s

P
A
M
4

/

λ
×

16

λ

) total capacity. By deploying an SLM-based beam tracking technology, the laser beam misalignment problem is practically resolved for providing an FSO link with high link accessibility. This demonstrated WDM-PAM4 FSO link fully meets the requirements of high-speed, long-reach, and high-reliability transmissions.
Influence of incident angle, anisotropy, and floating distance on aerial imaging resolution
Authors: Kakinuma Ryota , Kawagishi Norikazu , Yasugi Masaki , Yamamoto Hirotsugu
Published: February 2021

We measure the image resolution of aerial images formed with an AIRR (aerial imaging by retro-reflection) system. Using three different types of retro-reflectors inside the AIRR system, we measure the aerial image modulation transfer function (MTF) via the slanted knife edge method, showing that the resolution of depends on the angle of incidence on the retro-reflector, the retro-reflector's anisotropy, and the aerial image's floating distance.
COVID-19 induces a hyperactive phenotype in circulating platelets
Authors: Comer Shane P. , Cullivan Sarah , Szklanna Paulina B. , Weiss Luisa , Cullen Steven , Kelliher Sarah , Smolenski Albert , Murphy Claire , Altaie Haidar , Curran John , O’Reilly Katherine , Cotter Aoife G. , Marsh Brian , Gaine Sean , Mallon Patrick , McCullagh Brian , Moran Niamh , Ní Áinle Fionnuala , Kevane Barry , Maguire Patricia B. ,   On behalf of the COCOON Study investigators
Published: February 2021

Coronavirus Disease 2019 (COVID-19), caused by the novel Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), has affected over 30 million globally to date. Although high rates of venous thromboembolism and evidence of COVID-19-induced endothelial dysfunction have been reported, the precise aetiology of the increased thrombotic risk associated with COVID-19 infection remains to be fully elucidated. Therefore, we assessed clinical platelet parameters and circulating platelet activity in patients with severe and nonsevere COVID-19. An assessment of clinical blood parameters in patients with severe COVID-19 disease (requiring intensive care), patients with nonsevere disease (not requiring intensive care), general medical in-patients without COVID-19, and healthy donors was undertaken. Platelet function and activity were also assessed by secretion and specific marker analysis. We demonstrated that routine clinical blood parameters including increased mean platelet volume (MPV) and decreased platelet:neutrophil ratio are associated with disease severity in COVID-19 upon hospitalisation and intensive care unit (ICU) admission. Strikingly, agonist-induced ADP release was 30- to 90-fold higher in COVID-19 patients compared with hospitalised controls and circulating levels of platelet factor 4 (PF4), soluble P-selectin (sP-selectin), and thrombopoietin (TPO) were also significantly elevated in COVID-19. This study shows that distinct differences exist in routine full blood count and other clinical laboratory parameters between patients with severe and nonsevere COVID-19. Moreover, we have determined all COVID-19 patients possess hyperactive circulating platelets. These data suggest abnormal platelet reactivity may contribute to hypercoagulability in COVID-19 and confirms the role that platelets/clotting has in determining the severity of the disease and the complexity of the recovery path.
A comprehensive computational model of animal biosonar signal processing
Authors: Ming Chen , Haro Stephanie , Simmons Andrea Megela , Simmons James A.
Published: February 2021

Computational models of animal biosonar seek to identify critical aspects of echo processing responsible for the superior, real-time performance of echolocating bats and dolphins in target tracking and clutter rejection. The Spectrogram Correlation and Transformation (SCAT) model replicates aspects of biosonar imaging in both species by processing wideband biosonar sounds and echoes with auditory mechanisms identified from experiments with bats. The model acquires broadband biosonar broadcasts and echoes, represents them as time-frequency spectrograms using parallel bandpass filters, translates the filtered signals into ten parallel amplitude threshold levels, and then operates on the resulting time-of-occurrence values at each frequency to estimate overall echo range delay. It uses the structure of the echo spectrum by depicting it as a series of local frequency nulls arranged regularly along the frequency axis of the spectrograms after dechirping them relative to the broadcast. Computations take place entirely on the timing of threshold-crossing events for each echo relative to threshold-events for the broadcast. Threshold-crossing times take into account amplitude-latency trading, a physiological feature absent from conventional digital signal processing. Amplitude-latency trading transposes the profile of amplitudes across frequencies into a profile of time-registrations across frequencies. Target shape is extracted from the spacing of the object’s individual acoustic reflecting points, or glints, using the mutual interference pattern of peaks and nulls in the echo spectrum. These are merged with the overall range-delay estimate to produce a delay-based reconstruction of the object’s distance as well as its glints. Clutter echoes indiscriminately activate multiple parts in the null-detecting system, which then produces the equivalent glint-delay spacings in images, thus blurring the overall echo-delay estimates by adding spurious glint delays to the image. Blurring acts as an anticorrelation process that rejects clutter intrusion into perceptions.
Robust COX-2-mediated prostaglandin response may drive arthralgia and bone destruction in patients with chronic inflammation post-chikungunya
Authors: Bedoui Yosra , Septembre-Malaterre Axelle , Giry Claude , Jaffar-Bandjee Marie-Christine , Selambarom Jimmy , Guiraud Pascale , Gasque Philippe
Published: February 2021

Patients following infection by chikungunya virus (CHIKV) can suffer for months to years from arthralgia and arthritis. Interestingly, methotrexate (MTX) a major immune-regulatory drug has proved to be of clinical benefit. We have previously shown that CHIKV can persist in the joint of one patient 18 months post-infection and plausibly driving chronic joint inflammation but through ill-characterized mechanisms. We have pursued our investigations and report novel histological andin vitrodata arguing for a plausible role of a COX-2-mediated inflammatory response post-CHIKV. In the joint, we found a robust COX-2 staining on endothelial cells, synovial fibroblasts and more prominently on multinucleated giant cells identified as CD11c+ osteoclasts known to be involved in bone destruction. The joint tissue was also strongly stained for CD3, CD8, CD45, CD14, CD68, CD31, CD34, MMP2, and VEGF (but not for NO synthase and two B cell markers). Dendritic cells were rarely detected. Primary human synovial fibroblasts were infected with CHIKV or stimulated either by the synthetic molecule polyriboinosinic:polyribocytidylic acid (PIC) to mimic chronic viral infection or cytokines. First, we found that PIC and CHIKV enhanced mRNA expression of COX-2. We further found that PIC but not CHIKV increased the mRNA levels of cPLA2α and of mPGES-1, two other central enzymes in PGE2 production. IFNβ upregulated cPLA2α and COX-2 transcription levels but failed to modulated mPGES-1 mRNA expression. Moreover, PIC, CHIKV and IFNβ decreased mRNA expression of the PGE2 degrading enzyme 15-PGDH. Interestingly, MTX failed to control the expression of all these enzymes. In sharp contrast, dexamethasone was able to control the capacity of pro-inflammatory cytokines, IL-1β as well as TNFα, to stimulate mRNA levels of cPLA2α, COX-2 and mPGES-1. These original data argue for a concerted action of CHIKV (including viral RNA) and cytokines plausibly released from recruited leukocytes to drive a major COX-2-mediated PGE2 proinflammatory responses to induce viral arthritis.
Feasibility of integrating canine olfaction with chemical and microbial profiling of urine to detect lethal prostate cancer
Authors: Guest Claire , Harris Rob , Sfanos Karen S. , Shrestha Eva , Partin Alan W. , Trock Bruce , Mangold Leslie , Bader Rebecca , Kozak Adam , Mclean Scott , Simons Jonathan , Soule Howard , Johnson Thomas , Lee Wen-Yee , Gao Qin , Aziz Sophie , Stathatou Patritsia Maria , Thaler Stephen , Foster Simmie , Mershin Andreas
Published: February 2021

Prostate cancer is the second leading cause of cancer death in men in the developed world. A more sensitive and specific detection strategy for lethal prostate cancer beyond serum prostate specific antigen (PSA) population screening is urgently needed. Diagnosis by canine olfaction, using dogs trained to detect cancer by smell, has been shown to be both specific and sensitive. While dogs themselves are impractical as scalable diagnostic sensors, machine olfaction for cancer detection is testable. However, studies bridging the divide between clinical diagnostic techniques, artificial intelligence, and molecular analysis remains difficult due to the significant divide between these disciplines. We tested the clinical feasibility of a cross-disciplinary, integrative approach to early prostate cancer biosensing in urine using trained canine olfaction, volatile organic compound (VOC) analysis by gas chromatography-mass spectroscopy (GC-MS) artificial neural network (ANN)-assisted examination, and microbial profiling in a double-blinded pilot study. Two dogs were trained to detect Gleason 9 prostate cancer in urine collected from biopsy-confirmed patients. Biopsy-negative controls were used to assess canine specificity as prostate cancer biodetectors. Urine samples were simultaneously analyzed for their VOC content in headspace via GC-MS and urinary microbiota content via 16S rDNA Illumina sequencing. In addition, the dogs’ diagnoses were used to train an ANN to detect significant peaks in the GC-MS data. The canine olfaction system was 71% sensitive and between 70–76% specific at detecting Gleason 9 prostate cancer. We have also confirmed VOC differences by GC-MS and microbiota differences by 16S rDNA sequencing between cancer positive and biopsy-negative controls. Furthermore, the trained ANN identified regions of interest in the GC-MS data, informed by the canine diagnoses. Methodology and feasibility are established to inform larger-scale studies using canine olfaction, urinary VOCs, and urinary microbiota profiling to develop machine olfaction diagnostic tools. Scalable multi-disciplinary tools may then be compared to PSA screening for earlier, non-invasive, more specific and sensitive detection of clinically aggressive prostate cancers in urine samples.
A humanized CD3ε-knock-in mouse model for pre-clinical testing of anti-human CD3 therapy
Authors: Crespo Joel , Koh Yi Ting , Hu Ningjie , Moore Paul A. , Bonvini Ezio , Glasebrook Andrew L. , Martin Andrea P. , Benschop Robert J.
Published: February 2021

Pre-clinical murine models are critical for translating drug candidates from the bench to the bedside. There is interest in better understanding how anti-human CD3 therapy works based on recent longitudinal studies of short-term administration. Although several models have been created in this pursuit, each have their own advantages and disadvantages in Type-1 diabetes. In this study, we report a murine genetic knock-in model which expresses both a murine and a humanized-CD3ε-exon, rendering it sensitive to manipulation with anti-human CD3. These huCD3εHET mice are viable and display no gross abnormalities. Specifically, thymocyte development and T cell peripheral homeostasis is unaffected. We tested immune functionality of these mice by immunizing them with T cell-dependent antigens and no differences in antibody titers compared to wild type mice were recorded. Finally, we performed a graft-vs-host disease model that is driven by effector T cell responses and observed a wasting disease upon transfer of huCD3εHET T cells. Our results show a viable humanized CD3 murine model that develops normally, is functionally engaged by anti-human CD3 and can instruct on pre-clinical tests of anti-human CD3 antibodies.
Negative attitudes about facemasks during the COVID-19 pandemic: The dual importance of perceived ineffectiveness and psychological reactance
Authors: Taylor Steven , Asmundson Gordon J. G.
Published: February 2021

This study reports a comprehensive empirical investigation of the nature and correlates of anti-mask attitudes during the COVID-19 pandemic. Accumulating evidence underscores the importance of facemasks, as worn by the general public, in limiting the spread of infection. Accordingly, mask wearing has become increasingly mandatory in public places such as stores and on public transit. Although the public has been generally adherent to mask wearing, a small but vocal group of individuals refuse to wear masks. Anti-mask protest rallies have occurred in many places throughout the world, sometimes erupting violently. Few empirical studies have examined the relationship between anti-mask attitudes and mask non-adherence and little is known about how such attitudes relate to one another or other factors (e.g., non-adherence to social distancing, anti-vaccination attitudes). To investigate these issues, the present study surveyed 2,078 adults from the US and Canada. Consistent with other surveys, we found that most (84%) people wore masks because of COVID-19. The 16% who did not wear masks scored higher on most measures of negative attitudes towards masks. Network analyses indicated that negative attitudes about masks formed an intercorrelated network, with the central nodes in the network being (a) beliefs that masks are ineffective in preventing COVID-19, and (b) psychological reactance (PR; i.e., an aversion to being forced to wear masks). These central nodes served as links, connecting the network of anti-masks attitudes to negative attitudes toward SARSCoV2 vaccination, beliefs that the threat of COVID-19 has been exaggerated, disregard for social distancing, and political conservatism. Findings regarding PR are important because, theoretically, PR is likely to strengthen other anti-masks attitudes (e.g., beliefs that masks are ineffective) because people with strong PR react with anger and counter-arguments when their beliefs are challenged, thereby leading to a strengthening of their anti-mask beliefs. Implications for improving mask adherence are discussed.
Novel health system strategies for tuberculin skin testing at primary care clinics: Performance assessment and health economic evaluation
Authors: Van Ginderdeuren Eva , Bassett Jean , Hanrahan Colleen F. , Mutunga Lillian , Van Rie Annelies
Published: February 2021

Background

Tuberculin skin test (TST) for guiding initiation of tuberculosis preventive therapy poses major challenges in high tuberculosis burden settings.

Methods

At a primary care clinic in Johannesburg, South Africa, 278 HIV-positive adults self-read their TST by reporting if they felt a bump (any induration) at the TST placement site. TST reading (in mm) was fast-tracked to reduce patient wait time and task-shifted to delegate tasks to lower cadre healthcare workers, and result was compared to TST reading by high cadre research staff. TST reading and placement cost to the health system and patients were estimated. Simulations of health system costs were performed for 5 countries (USA, Germany, Brazil, India, Russia) to evaluate generalizability.

Results

Almost all participants (269 of 278, 97%) correctly self-identified the presence or absence of any induration [sensitivity 89% (95% CI 80,95) and specificity 99.5% (95% CI 97,100)]. For detection of a positive TST (induration ≥ 5mm), sensitivity was 90% (95% CI 81,96) and specificity 99% (95% CI 97,100). TST reading agreement between low and high cadre staff was high (kappa 0.97, 95% CI 0.94, 1.00). Total TST cost was 2066 I$ (95% UI 594, 5243) per 100 patients, 87% (95% UI 53, 95) of which were patient costs. Combining fast-track and task-shifting, reduced total costs to 1736 I$ (95% UI 497, 4300) per 100 patients, with 31% (95% UI 15, 42) saving in health system costs. Combining fast-tracking, task-shifting and self-reading, lowered the TST health system costs from 16% (95% UI 8, 26) in Russia to 40% (95% UI 18, 54) in the USA.

Conclusion

A TST strategy where only patients with any self-read induration are asked to return for fast-tracked TST reading by lower cadre healthcare workers is a promising strategy that could be effective and cost-saving, but real-life cost-effectiveness should be further examined.
The relative contribution of intraspecific variation and species turnover to the community-level foliar stoichiometric characteristics in different soil moisture and salinity habitats
Authors: Tusifujiang Yelike , Zhang Xueni , Gong Lu
Published: February 2021

Background

Trait-based approaches have been used to demonstrate the responses of plant functional traits to environmental change may manifest both among- and/or within-species. However, how community-level foliar stoichiometric characteristic variations respond to aridity and salinity is still not well-known.

Methods

We calculated community weighted means (CWMs) and non-weighted means (CMs) of foliar C, N, and P concentrations (and their ratios) in a dryland plant community respond to high (HSW) and low soil moisture and salinity (LSW). Based on a sum of squares decomposition method, we determined the relative contributions of intraspecific variation and species turnover in both HSW and LSW habitats.

Results

The CWMs of foliar C, C:N and C:P, and CM of N in the HSW habitat were significantly greater than those in the LSW habitat. The trait variations in two habitats were mainly driven by intraspecific variation, and its contribution to trait variation mostly declined with the decrease of soil moisture and salinity. The CWMs of foliar C-related stoichiometric characteristics were mainly dominated by species turnover in both habitats. Moreover, the contribution of species turnover to C and C:P variations showed an increasing trend in the LSW habitat. For CWMs, negative covariations between intraspecific variation and turnover occurred in HSW and positive covariations (except N:P) occurred in LSW; however, CMs were generally positively correlated in both habitats.

Conclusions

The intraspecific variation declined as drought stress intensified, which indicates that the adaptability of desert plants declined when the stress changed from salinity to aridity. The total variation of C-related traits in both habitats were mainly dominated by species turnover. These findings highlight the importance of intraspecific variation in driving desert plant response of community functional composition to salt stress, and the joint role of intraspecific variation and species turnover in resisting drought stress.
Relationship dynamics and anticipated stigma: Key considerations for PrEP use among Tanzanian adolescent girls and young women and male partners
Authors: Jani Nrupa , Mathur Sanyukta , Kahabuka Catherine , Makyao Neema , Pilgrim Nanlesta
Published: February 2021

Objectives

We examined key gender, interpersonal and community dynamics influencing PrEP acceptability among adolescent girls and young women (AGYW) and their male partners.

Methods

We administered 12 in-depth interviews (IDI) to partnered, or married AGYW aged 15–24 years living without HIV, and 16 IDIs to male partners living without HIV aged 18 or older, partnered or married to an AGYW in Tanzania. Card sorting, a participatory qualitative method for facilitating systematic discussion, was used to identify attitudes, values, and desires that would influence PrEP acceptability.

Results

Relationship distrust, partner communication about HIV risk, and need to control HIV risk were highly influential considerations for PrEP use. AGYW and male partners both wanted to discuss PrEP use amidst relationship distrust, while most male partners encouraged AGYW PrEP use for shared protective benefit. Anticipated stigma of being perceived as a person living with HIV, as a result of PrEP use, was a deterrent for both AGYW and male partners while AGYW also feared additional stigma of being considered sexually promiscuous.

Conclusions

Couples counseling for PrEP uptake and adherence might be a well-placed strategy for couples who are living without HIV to educate one another about the relationship benefits of using PrEP, thereby increasing its acceptance and adherence, addressing unequal power dynamics, and reducing associated relationship distrust. Community awareness and education about PrEP can help curb persistent PrEP stigma, including intersectional stigma.
The critical importance of mask seals on respirator performance: An analytical and simulation approach
Authors: Xu Mingxin , Lee Peter , Collins David
Published: February 2021

Filtering facepiece respirators (FFRs) and medical masks are widely used to reduce the inhalation exposure of airborne particulates and biohazardous aerosols. Their protective capacity largely depends on the fraction of these that are filtered from the incoming air volume. While the performance and physics of different filter materials have been the topic of intensive study, less well understood are the effects of mask sealing. To address this, we introduce an approach to calculate the influence of face-seal leakage on filtration ratio and fit factor based on an analytical model and a finite element method (FEM) model, both of which take into account time-dependent human respiration velocities. Using these, we calculate the filtration ratio and fit factor for a range of ventilation resistance values relevant to filter materials, 500–2500 Pa∙s∙m−1, where the filtration ratio and fit factor are calculated as a function of the mask gap dimensions, with good agreement between analytical and numerical models. The results show that the filtration ratio and fit factor are decrease markedly with even small increases in gap area. We also calculate particle filtration rates for N95 FFRs with various ventilation resistances and two commercial FFRs exemplars. Taken together, this work underscores the critical importance of forming a tight seal around the face as a factor in mask performance, where our straightforward analytical model can be readily applied to obtain estimates of mask performance.
Factors influencing the delivery and uptake of early infant diagnosis of HIV services in Greater Accra, Ghana: A qualitative study
Authors: Ankrah Antoinette Kailey , Dako-Gyeke Phyllis
Published: February 2021

Background

Early Infant Diagnosis (EID) of HIV and timely initiation of Antiretroviral Therapy (ART) can significantly reduce morbidity and mortality of HIV infected infants. Despite the benefits of early infant testing, the coverage of EID of HIV services is still low in Sub-Saharan Africa, including Ghana.

Objectives

To ascertain the factors that facilitate or hinder the delivery and uptake of EID of HIV services.

Methods

The study is a cross-sectional exploratory qualitative research conducted in two health facilities in the Greater Accra Region of Ghana. Respondents (n = 50) comprising health workers (n = 20) and HIV positive mothers (n = 30) were purposively sampled and engaged in in-depth interviews. The Nvivo 11 software and the Braun and Clarke’s stages of thematic analysis were used in coding data and data analysis respectively.

Results

The study found that health system factors such as inadequate Staff with sample collection skills, unavailability of vehicles to convey samples to the reference laboratory for analysis, the long turnaround time for receipt of Polymerase Chain Reaction (PCR) results, inadequate and frequent breakdown of PCR machine hindered EID service delivery. On the other hand, adequate knowledge of health workers on EID, availability of Dried Blood Spot (DBS) cards and the adoption of task shifting strategies facilitated EID service delivery. Factors such as the denial of HIV status, non-completion of the EID process due to frustrations encountered whiles accessing service and delay in receipt of PCR results served as barriers to mother’s utilisation of EID services for their exposed infants. The study also identified that adequate knowledge of EID, perceived importance of EID, financial stability as well as financial support from others and the positive attitudes of health workers facilitated HIV positive mother’s uptake of EID services for their exposed infants.

Conclusion

The factors attributing to the low coverage of EID of HIV services must be promptly addressed to improve service delivery and uptake.
Impact of COVID-19 pandemic on the utilization of routine immunization services in Lebanon
Authors: Mansour Ziad , Arab Jinan , Said Racha , Rady Alissar , Hamadeh Randa , Gerbaka Bernard , Bizri Abdul Rahman
Published: February 2021

Introduction

The global abrupt progression of the COVID-19 pandemic may disrupt critical life-saving services such as routine immunization (RI), thus increasing the susceptibility of countries to outbreaks of vaccine-preventable diseases (VPDs). Being endemic to several infectious diseases, Lebanon might be at increased risk of outbreaks as the utilization of RI services might have deteriorated due to the pandemic and the country’s political unrest following the October 2019 uprising. The aim of this study was to assess the changes in the utilization of RI services in both the public and private sectors following the COVID-19 pandemic.

Methods

A self-administered cross-sectional survey was completed electronically, in April 2020, by 345 private pediatricians who are registered in professional associations of physicians in Lebanon and provide immunization services at their clinics. Means of the reported percentages of decrease in the utilization of vaccination services by pediatricians were calculated. As for the public sector, an examination of the monthly differences in the number of administered vaccine doses in addition to their respective percentages of change was performed. Adjustment for the distribution of RI services between the sectors was performed to calculate the national decrease rate.

Results

The utilization of vaccination services at the national level decreased by 31%. In the private sector, immunization services provision diminished by 46.9% mainly between February and April 2020. The highest decrease rates were observed for oral poliovirus vaccine (OPV) and hepatitis A, followed by measles and pneumococcal conjugate vaccines. The number of vaccine doses administered in the public sector decreased by 20%. The most prominent reductions were detected for the OPV and measles vaccines, and during October 2019 and March 2020.

Conclusion

The substantial decrease in the utilization of RI as a result of the COVID-19 pandemic requires public health interventions to prevent future outbreaks of VPDs.
Genetic diversity of Ethiopian durum wheat landraces
Authors: Negisho Kefyalew , Shibru Surafel , Pillen Klaus , Ordon Frank , Wehner Gwendolin
Published: February 2021

Genetic diversity and population structure assessment in crops is essential for marker trait association, marker assisted breeding and crop germplasm conservation. We analyzed a set of 285 durum wheat accessions comprising 215 Ethiopian durum wheat landraces, 10 released durum wheat varieties, 10 advanced durum wheat lines from Ethiopia, and 50 durum wheat lines from CIMMYT. We investigated the genetic diversity and population structure for the complete panel as well as for the 215 landraces, separately based on 11,919 SNP markers with known physical positions. The whole panel was clustered into two populations representing on the one hand mainly the landraces, and on the other hand mainly released, advanced and CIMMYT lines. Further population structure analysis of the landraces uncovered 4 subgroups emphasizing the high degree of genetic diversity within Ethiopian durum landraces. Population structure based AMOVA for both sets unveiled significant (P < 0.001) variation between populations and within populations. Total variation within population accessions (81%, 76%) was higher than total variation between populations (19%, 24%) for both sets. Population structure analysis based genetic differentiation (FST) and gene flow (Nm) for the whole set and the Ethiopian landraces were 0.19 and 0.24, 1.04, and 0.81, respectively indicating high genetic differentiation and limited gene flow. Diversity indices verify that the landrace panel was more diverse with (I = 0.7, He = 0.46, uHe = 0.46) than the advanced lines (I = 0.6, He = 0.42, uHe = 0.42). Similarly, differences within the landrace clusters were observed. In summary a high genetic diversity within Ethiopian durum wheat landraces was detected, which may be a target for national and international wheat improvement programs to exploit valuable traits for biotic and abiotic stresses.
Phytochemical characterization of turnip greens (Brassica rapa ssp. rapa): A systematic review
Authors: Dejanovic Gordana M. , Asllanaj Eralda , Gamba Magda , Raguindin Peter Francis , Itodo Oche Adam , Minder Beatrice , Bussler Weston , Metzger Brandon , Muka Taulant , Glisic Marija , Kern Hua
Published: February 2021

Objective

The Turnip (Brassica rapa L. ssp. rapa) is a leaf and root vegetable grown and consumed worldwide. The consumption of Turnip has been associated with beneficial effects on human health due to their phytochemicals that may control a variety of physiological functions, including antioxidant activity, enzyme regulation, and apoptotic control and the cell cycle. The current systematic review of the literature aims to evaluate both the profile and quantity of phytochemicals commonly found in Turnip greens and to provide perspectives for further investigation.

Methods

This review was conducted following the PRISMA guidelines. Four bibliographic databases (PubMed, Embase, Web-of-Science and Cochrane Central Register of Controlled Trials) were searched to identify published studies until April 8th, 2020 (date last searched) without data and language restriction. Studies were included if they used samples of Turnip greens (the leaves), and evaluated its phytochemical content. Two reviewers independently evaluated the titles and abstracts according to the selection criteria. For each potentially eligible study, two reviewers assessed the full-texts and independently extracted the data using a predesigned data extraction form.

Results

Based on the search strategy 5,077 potentially relevant citations were identified and full texts of 37 studies were evaluated, among which 18 studies were eligible to be included in the current review. The majority of included studies were focused on identification of glucosinolates and isothiocyanates (n = 14, 82%), four studies focused on organic acids, and five studies reported phenolic component profile in Turnip greens. Among included studies nine studies (50%) provided information on phytochemical’s content. We found 129 phytochemicals (19 glucosinolates, 33 glucosinolate-breakdown products, 10 organic acids and 59 polyphenolic compounds) reported in Turnip greens. Flavonoids were mainly present as quercetin, kaempferol and isorhamnetin derivatives; while aliphatic forms were the predominant glucosinolate (gluconapin was the most common across five studies, followed by glucobrassicanapin). In general, the phytochemical content varied among the leaves, tops and Turnip roots.

Conclusions

Emerging evidence suggests the Turnip as a substantial source of diverse bioactive compounds. However, detailed investigation on the pure compounds derived from Turnip green, their bioavailability, transport and metabolism after consumption is further needed. Additional studies on their biological activity are crucial to develop dietary recommendations on the effective dosage and dietary recommendation of Turnip greens for nutrition and health.
Is a verification phase useful for confirming maximal oxygen uptake in apparently healthy adults? A systematic review and meta-analysis
Authors: Costa Victor A. B. , Midgley Adrian W. , Carroll Sean , Astorino Todd A. , de Paula Tainah , Farinatti Paulo , Cunha Felipe A.
Published: February 2021

Background

The ‘verification phase’ has emerged as a supplementary procedure to traditional maximal oxygen uptake (VO2max) criteria to confirm that the highest possible VO2 has been attained during a cardiopulmonary exercise test (CPET).

Objective

To compare the highest VO2 responses observed in different verification phase procedures with their preceding CPET for confirmation that VO2max was likely attained.

Methods

MEDLINE (accessed through PubMed), Web of Science, SPORTDiscus, and Cochrane (accessed through Wiley) were searched for relevant studies that involved apparently healthy adults, VO2max determination by indirect calorimetry, and a CPET on a cycle ergometer or treadmill that incorporated an appended verification phase. RevMan 5.3 software was used to analyze the pooled effect of the CPET and verification phase on the highest mean VO2. Meta-analysis effect size calculations incorporated random-effects assumptions due to the diversity of experimental protocols employed. I2 was calculated to determine the heterogeneity of VO2 responses, and a funnel plot was used to check the risk of bias, within the mean VO2 responses from the primary studies. Subgroup analyses were used to test the moderator effects of sex, cardiorespiratory fitness, exercise modality, CPET protocol, and verification phase protocol.

Results

Eighty studies were included in the systematic review (total sample of 1,680 participants; 473 women; age 19–68 yr.; VO2max 3.3 ± 1.4 L/min or 46.9 ± 12.1 mL·kg-1·min-1). The highest mean VO2 values attained in the CPET and verification phase were similar in the 54 studies that were meta-analyzed (mean difference = 0.03 [95% CI = -0.01 to 0.06] L/min, P = 0.15). Furthermore, the difference between the CPET and verification phase was not affected by any of the potential moderators such as verification phase intensity (P = 0.11), type of recovery utilized (P = 0.36), VO2max verification criterion adoption (P = 0.29), same or alternate day verification procedure (P = 0.21), verification-phase duration (P = 0.35), or even according to sex, cardiorespiratory fitness level, exercise modality, and CPET protocol (P = 0.18 to P = 0.71). The funnel plot indicated that there was no significant publication bias.

Conclusions

The verification phase seems a robust procedure to confirm that the highest possible VO2 has been attained during a ramp or continuous step-incremented CPET. However, given the high concordance between the highest mean VO2 achieved in the CPET and verification phase, findings from the current study would question its necessity in all testing circumstances.

PROSPERO Registration ID

CRD42019123540.