bluuebunny/crossref_metadata_2025 huggingface dataset:
Realization of LNA and Mixer Using CMOS 0.18μm Technology for 3.1 to 10.6 GHz
Authors: Kalra Dheeraj
Published: May 2021

In this paper, low noise amplifier and mixer circuits are realized using 0.18μm CMOS technology in the frequency range of 3.1 to 10.6 GHz. LNA circuit uses the cascade topology with source degeneration technique, which help in reducing the non-linearity in the circuit. The current reuse topology is used to decrease the biasing voltage and hence to decrease the power consumption in the circuit. Realized circuit simulated in 0.18μm technology and various results shows highest gain S21 is 19.982dB and has the positive value in the entire frequency band, minimum NFmin is 1.270dB occurs at 1.27GHz and the highest NFmin is 3.4dB. S11 i.e. input reflection coefficient is -31.670dB and it is negative throughout the entire frequency range while the reflection at output port is report to be -7.449 dB. The resistive feedback topology helps in getting the flat gain in the frequency. Mixer circuit is also realize in 0.18μm CMOS technology, which uses current bleeding topology. Transformer help in converting the single ended signal into differential format. Maximum value of gain is 6.584dB, gain is positive in the entire RF frequency range, S11 i.e. the reflection at port1, which give the negative values in the entire frequency band, simulation of S12 i.e. leakage between the port 1 and 2 has negative values in the entire frequency band means proper isolation between the ports. The future work can the realization of the superheterodyne receiver in UWB band.
Application of Radio frequency identification technique in Developing Countries
Authors: Srivastava Shashank
Published: May 2021

Radio frequency identification (RFID) technique is a practice for managing the supply Chain of healthcare. Technique of Radio Frequency Identification (RFID) not just offers following ability of different resources continuously, yet in addition gives productive and exact access to healthcare information for specialists and other experts of healthcare sector. The primary challenge faced by RFID is its acceptance and utilization by doctors and medical attendants only. This paper utilizes semi-organized questionnaires on RFID advisors, scientists, and medical hospitals directors/doctors. Information was gathered from 150 doctors and attendants/nurses. The development of RFID adoption in the developing countries is still in the initial phase. The significant barriers, advantages, application and critical success factors of RFID have been recognized in this paper. This study adds to the developing interest for understanding the RFID adoption in the healthcare services industry. The motivation behind this research is to understand the current opportunities, potential advantages of RFID adoption in Indian healthcare industry.
Cooling of electronic components on the LTCC module with an embedded flat heat pipe
Authors: Nesterov D A , Derevyanko V A , Suntsov S B
Published: May 2021

The results of the experimental investigations of a ceramic circuit board sample with an embedded flat heat pipe are presented. The sample was made based on the technology of low temperature co-fired ceramic (LTCC). The flat heat pipe is formed at the bottom side of a ceramic substrate using a capillary structure made of sintered copper powder. The developed prototype of the LTCC module was used for the investigation of removing and spreading of high heat fluxes from high power electronic components mounted on the module. The embedded flat heat pipe filled with acetone provides 40 W/cm2 of heat flux removal from the heat source with the heat dissipation area of 1 cm2. The measured value of the thermal resistance between the heat source and cooler surface under the module is 0.8 °C/W.
Loop thermosyphons with porous coatings
Authors: Vasiliev L L , Rabetsky M I , Grakovich L P , Kulikouski V K , Zhuravlyov A S , Kuzmich M A
Published: May 2021

The aim of this work is to experimentally evaluate the heat exchange of evaporation and condensation inside a new annular thermosyphon with horizontally located zones of evaporation and condensation, which are interconnected by a vapor line and a condensate line. The mini-tube of the liquid line is introduced coaxially into the cylindrical evaporator with a porous coating, thus an annular channel is formed between the tube and the porous coating of the evaporator. The purpose of this study is to determine the thermal resistance of the device and its components, as well as the temperature field along the thermosyphon. The considered thermosyphon guarantees a shorter start-up time, lowers the temperature of the evaporator walls, has a small temperature hysteresis with an increase/decrease in the transferred heat flux, and suppresses temperature pulsations inside an evaporator. The 130 mm long evaporator is made of copper tube (d
out = 12 mm, d
in = 10 mm). The wick is obtained by sintering copper powder. The working fluids R245fa and R600 were used. The thermal resistance of thermosyphon does not exceed 0.5 K/W, and of the evaporator 0.1–0.05 K/W).
Interference Mitigation in the Wireless Communication Systems Using Adaptive Filters
Authors: Mohammed Jafar Ramadhan
Published: May 2021

In the current fifth generation (5G) wireless communication systems, the interference mitigation issue becomes a major and most important task for improving the performance of such systems due to corded spectrum and increased demands for new applications. Antenna arrays controlled by adaptive algorithms are proved to be a good solution for such problem. However, there are still some practical limitations in implementing such fully adaptive arrays especially when consisting a large number of the controllable elements. Other disadvantages of such arrays include long convergence time of the algorithm and the complexity of the beamforming network. In this paper, an adaptive algorithm is connected to only limited number of the array elements instead of all elements. We found that the elements that located on the center of the array could be chosen as adaptive, while the other elements which have less effect on the array pattern are left without adaptation process. Thus, the proposed array has many advantages with compared to those of the fully adaptive arrays while maintaining the same performance in suppressing the interference signals through null steering. Simulation results show that the effectiveness of the proposed array in generating deep nulls with very short convergence time.
A Beam Steering System Design based on Phased Array Antennas
Authors: Younus Karam Mudhafar , Abdulbari Jasim Ahmed , Clarke Roger W.
Published: May 2021

This paper presents a low-cost, compact, beam-steering phased array antenna (PAA) system based on a novel approach to integrating low-cost, high-performance phased shifters with their controlling boards within an antenna structure. Consequently, the system has been reduced to one structure for the antenna array and integrated phase shifters, rather than the sophisticated PAA with two separate boards which are connected by RF coaxial cables. The system has been achieved by the following stages; Firstly, the steering vector weights matrix was calculated by MATLAB. Then, four elements of uniform linear Microstrip patch antenna array with their feeding network power divider were designed and simulated in the CST simulation program. As a result, a practical model has been implemented. The designed RF-PCB for the 4-bit phase shifters MAPS_010143 were integrated within the antenna panel. The system works at a resonance frequency of (2.4 GHz), with (±45°) steering capability. The results are presented for the three models. The practical results match the simulation results very closely, fence proving the accuracy of the model and demonstrating a highly effective design.
An adaptive search direction algorithm for the modified projection minimization optimization
Authors: Al-Kawaz Rana Z. , Al-Bayati Abbas Y.
Published: May 2021

In this paper, we proposed a double-search direction algorithm with a free of derivatives based on a different parameter update (n k
) which gives us an update on the double search trend. We used anewly updated formula for the projection parameter within the formula for the proposed search direction. When comparing our numerical results for the proposed algorithm with some standard published algorithmswe obtain efficient numerical results. The proposed algorithm, especially, isused to solve large-scale nonlinear problems by combining two search directions in one search direction. Also, to demonstrate the general convergence of the proposed new algorithm under some circumstances. The numerical performance of the new proposed algorithm on some nonlinear test functions proved the efficiency of this algorithm.
Filter Design for A Fractional N-PLL Frequency Synthesizer At 2.4 GHz
Authors: Naktel Nour Zaid , Mohammed K.K. , Yonis A. Z.
Published: May 2021

Radio frequency transmitter and receivers usually needs an efficient frequency synthesizer, and this synthesizer must use a digital electronic circuit to perform different modern digital application which contain a frequency synthesizer circuit as a main part of the circuits. The fractional-N phase locked loop (PLL) has been used widely in the last twenty year ago because it gives a large bandwidth with fine frequency resolution for various electronic applications. This research presents the design of second order low pass filter at a frequency bandwidth of (50,75,125,250,500) kHz and for each value of the phase margin (30,35,40,47,57,65,70,80) degree, the component values of the filters which the capacitors and resistance were found at each values of the frequency bandwidth and for each phase margin, also the filter impedance, open loop and closed loop gain was calculated, it is found that by proper design of the second order low pass filter component, the system can have more stability operation and the spurs noise in the output can be reduced efficiently.
Improved resolution for separation between acoustical transmitters with their locations using Eigenvector algorithm
Authors: Qaba Azzah T , Al-azzo Mujahid F
Published: May 2021

Through the mathematical model that is derived to localize and separate acoustic sources. We used two methods and compared the results of them: classical method (Fourier transform), with the newer method (Eigenvector) or what represents (super resolution). The results of the comparison revealed the superiority of (Eigenvector) over (Fourier transform) in several aspects, the most important of which are contiguous sources in addition to the location of the sources. The study relied on a set of different criteria directly related to the problem.
Study of defects in CH3NH3PbI3-based perovskite solar cells
Authors: Ibrahim Hajar Kh , Sabaawi Ahmed M A , Algwari Qais Th
Published: May 2021

The present work will focus on the investigation of the influence of defects density and carriers capture cross-section are in absorption layer on the performance of perovskite solar cells. Furthermore, the impact of defect density in the electron transport material ETM/absorber interface layer will also be studied. The hybrid halide perovskite solar cells are chosen in this work and will be simulated by using one-dimension solar cells capacitance simulation SCAPS-1D. The proposed structure of the perovskite solar cell is a planar FTO/ETM/perovskite/HTM based on TiO2
and Spiro-OMeTAD as electron transport layer ETM and hole transport layer HTM, respectively, and on CH 3NH 3PbI 3
as absorber layer (perovskite). The results showed that when the defect density in the absorber layer was varied from 10 10cm -3 to 10 18 cm -3, the cell parameters, open circuit voltage (V
oc), the short circuit current (J sc
), the fill factor (FF), and the efficiency (PCE)were significantly decreased. At high defect density (10 18 cm -3), the defect affects negatively on the cell performance due to the high recombination rate of Shockley Read Hall. Similarly, the capture cross section exhibits similar behaviour in the active layer. By increasing the defect density in the ETM/absorber interface layer, the main cell parameters PCE, FF, and J sc
are slightly reduced and there has been no noticeable impact on V oc
.
Numerical Modelling of Pollutant Transport in a Straight Narrow Channel using Upwind Finite Difference Method
Authors: Yip B F , Alias N A F , Kasiman E H
Published: May 2021

River pollution has become an increasingly severe issue, resulting in the rapid depletion of freshwater resources. An accurate prediction of the transport of the pollutants is vital for effective mitigation measures. This paper presents the numerical modelling of pollutant transport in a straight narrow channel. The pollutant transport is modelled using an advection-diffusion equation. The equation is discretized using Finite Difference Method (FDM) with an explicit upwind scheme for the temporal term. The resulting system of simultaneous equations is solved using a direct method. The numerical model is validated against an existing analytical solution, and the results show good agreement between numerical prediction and analytical solution. The validated numerical model is applied to different cases of pollutant release mechanisms involving continuous and instantaneous pollutant releases. In both cases, the numerical model can capture the physics of the problem and able to provide valuable information on the time and spatial evolution of pollutant concentration. The model is extendable to higher dimension owing to its simplicity of discretization.
The framework for assessing public transportation by using competitiveness index indicators
Authors: Sinniah G K , Li X Y , Abdulkarim S
Published: May 2021

Many institutes measured and published the competitiveness ranking, in various fields of study and research as well as in the urban planning and development processes. While the city transportation is one of the main components that always be assessed from different dimensions, however people prefer to focus on pre planning and construction by exploring and measuring the effectiveness level after completion. In this paper, we assess public transportation competitiveness in terms of the bus system based on a self-evaluation framework built from numerous measuring variables to identify the current situation in the study case city Johor Bahru, Malaysia. We comply with the PCA (Principle components analysis) to divide the evaluating indicators to three categories, and eventually use TOPSIS and Fuzzy algorithm to evaluate the bus system. The study found significant improvement compared with the previous study evaluation that the competitiveness class from Bronze to Silver ranking. Simultaneously, we gained an evaluating framework from infrastructure, available and perception aspect that could be used in other places. The result verified that it is necessary and meaningful to verify the performance of the public transit system after completion due to we could revise or optimize it immediately to reach the expecting.
Anti-wear behaviour of silver nanoparticles on Al-Si alloy
Authors: Akgul Yasin , Simsir Hamza
Published: May 2021

In recent years, studies have shown that using nanoparticles (NPs) as lubricant additives lead to the enhancement of the anti-wear behaviour of oils. In this study, the anti-wear behaviour of silver (Ag) NPs which were capped with polyvinyl alcohol and sodium citrate were investigated for three different sliding speeds (2, 3 and 4 mm s−1) under two different loads (30 and 50 N). Results show that the AgNPs led to a decrease in friction and wear due to the formation of a tribofilm and a rolling effect. However, influence of the AgNPs declined at higher loads while increasing at higher speed test conditions. Also, both stabilising agents underwent disordering of AgNPs morphology and size successively under the applied loads.
Synthesis and corrosion resistance of Cu-Al-N nanostructured thin films deposited through magnetron sputtering
Authors: Otálora Barrero D M , Olaya J J , Duarte Moller A
Published: May 2021

Cu-Al-N thin films were deposited by means of the unbalanced magnetron cosputtering technique, varying the pulsed DC source power that is associated with the aluminum target. The structural characterization, done through x ray difraction (XRD) and transmition electronic microscopy (TEM), showed that the films were nanocrystalline, with a crystallite size of an order of magnitude of 10 nm. According to the chemical composition results, they consisted of a Cu-Al phase, copper nitride and aluminum nitride, that depended on the deposition power. The electrochemical characterization was performed by means of Tafel extrapolation and electrochemical impedance spectroscopy (EIS). The Tafel results showed a decrease in the corrosion current with an increase in the power, and the electrochemical impedance results showed an inductive behavior at low frequencies.
Does participant’s age impact on tDCS induced fields? Insights from computational simulations
Authors: McCann Hannah , Beltrachini Leandro
Published: May 2021

Objective: Understanding the induced current flow from transcranial direct current stimulation (tDCS) is essential for determining the optimal dose and treatment. Head tissue conductivities play a key role in the resulting electromagnetic fields. However, there exists a complicated relationship between skull conductivity and participant age, that remains unclear. We explored how variations in skull electrical conductivities, particularly as a suggested function of age, affected tDCS induced electric fields. Approach: Simulations were employed to compare tDCS outcomes for different intensities across head atlases of varying age. Three databases were chosen to demonstrate differing variability in skull conductivity with age and how this may affect induced fields. Differences in tDCS electric fields due to proposed age-dependent skull conductivity variation, as well as deviations in grey matter, white matter and scalp, were compared and the most influential tissues determined. Main results: tDCS induced peak electric fields significantly negatively correlated with age, exacerbated by employing proposed age-appropriate skull conductivity (according to all three datasets). Uncertainty in skull conductivity was the most sensitive to changes in peak fields with increasing age. These results were revealed to be directly due to changing skull conductivity, rather than head geometry alone. There was no correlation between tDCS focality and age. Significance: Accurate and individualised head anatomy and in vivo skull conductivity measurements are essential for modelling tDCS induced fields. In particular, age should be taken into account when considering stimulation dose to precisely predict outcomes.
A rank question for homogeneous polynomials
Authors: Brooks Jennifer , Palencia Kevin
Published: May 2021

A number of open problems in the field of several complex variables naturally lead to the study of bihomogeneous polynomials

r
(
z
,

z
¯

)

r(z,\bar {z})

on

C

n
+
1

\mathbb {C}^{n+1}

. In particular, both the Ebenfelt sum of squares conjecture and the degree estimate conjecture for proper rational mappings between balls in complex Euclidean spaces lead to the study of the rank of the bihomogeneous polynomial

r
(
z
,

z
¯

)

‖

z

‖

2

r(z,\bar {z}) \left \lVert {z}\right \rVert ^2

under certain additional hypotheses. When

r
r

has a diagonal coefficient matrix, these questions reduce to questions about real homogeneous polynomials. More specifically, we are led to study the rank of

P
=
S
Q

P=SQ

when

Q
Q

is a homogeneous polynomial and

S
(
x
)
=

∑

j
=
0

n

x
j

S(x) = \sum _{j=0}^n x_j

. In this paper, we use techniques from commutative algebra to estimate the minimum rank of

P
=
S
Q

P=SQ

under the additional hypothesis that

Q
Q

has maximum rank. The problem has already been solved for

n
+
1
≤
3

n+1 \leq 3

, and so we consider

n
+
1
≥
4

n+1\geq 4

. We obtain a minimum rank estimate that is sharp when

n
+
1
=
4

n+1=4

, and we exhibit a family of polynomials having this minimum rank. We also prove an estimate for

n
+
1
>
4

n+1>4

that, while not sharp, is non-trivial.
Let's meet at NAM 2021!
Authors: Bowler Sue
Published: May 2021

Sue Bowler talks to organizers Carole Mundell, Cathryn Mitchell and Patricia Schady about the first fully virtual National Astronomy Meeting in July
The Chicxulub impactor: comet or asteroid?
Authors: Desch Steve , Jackson Alan , Noviello Jessica , Anbar Ariel
Published: May 2021

Steve Desch, Alan Jackson, Jessica Noviello and Ariel Anbar assess the evidence for what type of object caused the end–Cretaceous extinction and suggest best practices for writing and reviewing inter–disciplinary papers
David Flower: Editor-in-chief, Monthly Notices of the RAS
Authors: Flower David
Published: May 2021

The astronomer has served on the MNRAS editorial board for more than 35 years, and since 2012 has steered it as it picked up speed through the digital age. Interview by Paul Johnson
The accurate prediction and characterization of cancerlectin by a combined machine learning and GO analysis
Authors: Tang Furong , Zhang Lichao , Xu Lei , Zou Quan , Feng Hailin
Published: May 2021

Cancerlectins, lectins linked to tumor progression, have become the focus of cancer therapy research for their carbohydrate-binding specificity. However, the specific characterization for cancerlectins involved in tumor progression is still unclear. By taking advantage of the g-gap tripeptide and tetrapeptide composition feature descriptors, we increased the accuracy of the classification model of cancerlectin and lectin to 98.54% and 95.38%, respectively. About 36 cancerlectin and 135 lectin features were selected for functional characterization by P/N feature ranking method, which particularly selects the features in positive samples. The specific protein domains of cancerlectins are found to be p-GalNAc-T, crystal and annexin by comparing with lectins through the exclusion method. Moreover, the combined GO analysis showed that the conserved cation binding sites of cancerlectin specific domains are covered by selected feature peptides, suggesting that the capability of cation binding, critical for enzyme activity and stability, could be the key characteristic of cancerlectins in tumor progression. These results will help to identify potential cancerlectin and provide clues for mechanism study of cancerlectin in tumor progression.
Desmond Tutu, George Carey and the Legalization of Euthanasia: A Response
Authors: Keown John
Published: May 2021

When two Christian prelates as internationally prominent as Desmond Tutu and George Carey call for the legalization of euthanasia and physician-assisted suicide, their arguments merit close consideration. This article sets out and evaluates their arguments. It concludes that the prelates rehearse the superficial case regularly advanced by euthanasia campaigners and fail adequately to engage with the arguments, both principled and practical, against legalization.
Plasma exchange with COVID-19 convalescent plasma in a patient with severe ANCA-associated vasculitis and COVID-19 pneumonia after rituximab therapy
Authors: Kochanek Matthias , Garcia Borrega Jorge , Beckmann Laura , Neuhann Julia , Gathof Birgit S , Di Cristanziano Veronica , Hagmann Henning
Published: May 2021

The combination of coronavirus disease 2019 (COVID-19) pneumonia and pulmonary–renal syndrome due to ANCA-associated vasculitis (AAV) poses diagnostic uncertainty and a therapeutic dilemma. According to current limited knowledge of COVID-19, the application of commonly used drugs in AAV, cyclophosphamide (CYC) and rituximab (RTX), must be weighed carefully in active COVID-19 infection. We report a case of a 52-year-old male patient with concurrent severe COVID-19 pneumonia and acute relapse of pulmonary–renal syndrome due to AAV after recent RTX maintenance dose. The patient presented with severe hypoxaemia, complete B-cell depletion and severe acute respiratory syndrome coronavirus 2 viraemia. He was successfully treated with therapeutic plasma exchange employing COVID-19 convalescent plasma.
Deep learning for vessel-specific coronary artery calcium scoring: validation on a multi-centre dataset
Authors: Winkel David J , Suryanarayana V Reddappagari , Ali A Mohamed , Görich Johannes , Buß Sebastian Johannes , Mendoza Axel , Schwemmer Chris , Sharma Puneet , Schoepf U Joseph , Rapaka Saikiran
Published: May 2021

Aims

To present and validate a fully automated, deep learning (DL)-based branch-wise coronary artery calcium (CAC) scoring algorithm on a multi-centre dataset.

Methods and results

We retrospectively included 1171 patients referred for a CAC computed tomography examination. Total CAC scores for each case were manually evaluated by a human reader. Next, each dataset was fully automatically evaluated by the DL-based software solution with output of the total CAC score and sub-scores per coronary artery (CA) branch [right coronary artery (RCA), left main (LM), left anterior descending (LAD), and circumflex (CX)]. Three readers independently manually scored the CAC for all CA branches for 300 cases from a single centre and formed the consensus using a majority vote rule, serving as the reference standard. Established CAC cut-offs for the total Agatston score were used for risk group assignments. The performance of the algorithm was evaluated using metrics for risk class assignment based on total Agatston score, and unweighted Cohen’s Kappa for branch label assignment. The DL-based software solution yielded a class accuracy of 93% (1085/1171) with a sensitivity, specificity, and accuracy of detecting non-zero coronary calcium being 97%, 93%, and 95%. The overall accuracy of the algorithm for branch label classification was 94% (LM: 89%, LAD: 91%, CX: 93%, RCA: 100%) with a Cohen's kappa of k = 0.91.

Conclusion

Our results demonstrate that fully automated total and vessel-specific CAC scoring is feasible using a DL-based algorithm. There was a high agreement with the manually assessed total CAC from a multi-centre dataset and the vessel-specific scoring demonstrated consistent and reproducible results.
Assessment of early exaggerated treatment effects in orthodontic interventions using cumulative meta-analysis
Authors: Seehra Jadbinder , Stonehouse-Smith Daniel , Pandis Nikolaos
Published: May 2021

Background

The reported initial strong treatment effects reported in early trials that are refuted in subsequent future studies assessing the same interventions have been attributed to novelty bias. The aim of this study was to determine whether there is any evidence of novelty bias in the reported treatment effects of orthodontics interventions.

Materials and methods

Relevant orthodontic systematic review (SRs) topics containing at least one meta-analysis on either binary or continuous outcomes with a minimum of three trials considered important areas in the field of orthodontic practice were identified. SR, meta-analysis, and primary study-level characteristics were extracted. Descriptive statistics were calculated at the SRs, meta-analysis, and at the individual study level. All SR and trial-level data were imported into the statistical software and all meta-analyses were replicated using the cumulative random-effects meta-analysis approach. Changes in the size and direction of the estimates between the first trial and the cumulative effect over time were recorded.

Results

Forty-seven meta-analyses were included. The total number of primary studies included within these meta-analyses was 408 (N = 408). Overall, the final effect size estimate decreased in 29 (61.7%, N = 29/47) cumulative meta-analyses whilst it increased in the remaining 18 (38.3%, N = 18/47). No association between the level of risk of bias and the cumulative absolute effect size was evident (OR 1.00; 95% CI: 0.98, 1.03; P = 0.717) after adjusting for year of the primary study (P = 0.22).

Conclusions

Clinicians should be wary of the results of trials reporting the effectiveness of new interventions as there is a possibility that the reported effect size will be often exaggerated.
Avian leukosis virus subgroup J infection alters viral composition in the chicken gut
Authors: Chen Yuan , Li Hong-Wei , Cong Feng , Lian Yue-Xiao
Published: May 2021

Chicken is one of the economically important poultry species. Avian leucosis virus subgroup J (ALV-J) has emerged as a serious cause of mortality and suboptimal performance of domestic chickens. Changes in virome may contribute to pathogenesis. Thus, it is important to investigate the effects of ALV-J infection on the composition of the virome in chicken. In the study metagenomic sequencing was used to characterize the virome of feces collected from the AVL-J infected chickens and the controls. Our results indicated that the chicken gut virome contained a diverse range of viruses that can be found in mammal, reptile, fish, and frogs. Furthermore, at the order, family and genus levels, AVL-J infection significantly altered the chicken gut virome composition. The predominant order was Herpesvirales, accounting for more than 96% of the chicken gut virome. Furthermore, the relative abundance of Caudovirales in the controls was higher than that in the AVL-J-infected chickens. At the family level, the relative abundance of Herpesviridae, Myoviridae, Alloherpesviridae, and Genomoviridae was significantly altered in the AVL-J-infected chickens compared with that in the controls. Additionally, the relative abundance of 15 genera showed a significant difference between the AVL-J-infected chickens and controls. These results will increase our understanding of the viral diversity and changes in the virome of chicken gut, with implications in chicken health.
A ban on BAM: an update on inhibitors of the β-barrel assembly machinery
Authors: Steenhuis Maurice , van Ulsen Peter , Martin Nathaniel I , Luirink Joen
Published: May 2021

Gram-negative pathogens are a rapidly increasing threat to human health worldwide due to high rates of antibiotic resistance and the lack of development of novel antibiotics. The protective cell envelope of gram-negative bacteria is a major permeability barrier that contributes to the problem by restricting the uptake of antibiotics. On the other hand, its unique architecture also makes it a suitable target for antibiotic interference. In particular, essential multiprotein machines that are required for biogenesis of the outer membrane have attracted attention in antibacterial design strategies. Recently, significant progress has been made in the development of inhibitors of the β-barrel assembly machine (BAM) complex. Here, we summarize the current state of drug development efforts targeting the BAM complex in pursuit of new antibiotics.
The Genomic Signature of Allopatric Speciation in a Songbird Is Shaped by Genome Architecture (Aves:Certhia americana)
Authors: Manthey Joseph D , Klicka John , Spellman Garth M
Published: May 2021

The genomic signature of speciation with gene flow is often attributed to the strength of divergent selection and recombination rate in regions harboring targets for selection. In contrast, allopatric speciation provides a different geographic context and evolutionary scenario, whereby introgression is limited by isolation rather than selection against gene flow. Lacking shared divergent selection or selection against hybridization, we would predict the genomic signature of allopatric speciation would largely be shaped by genomic architecture—the nonrandom distribution of functional elements and chromosomal characteristics—through its role in affecting the processes of selection and drift. Here, we built and annotated a chromosome-scale genome assembly for a songbird (Passeriformes: Certhia americana). We show that the genomic signature of allopatric speciation between its two primary lineages is largely shaped by genomic architecture. Regionally, gene density and recombination rate variation explain a large proportion of variance in genomic diversity, differentiation, and divergence. We identified a heterogeneous landscape of selection and neutrality, with a large portion of the genome under the effects of indirect selection. We found higher proportions of small chromosomes under the effects of indirect selection, likely because they have relatively higher gene density. At the chromosome scale, differential genomic architecture of macro- and microchromosomes shapes the genomic signatures of speciation: chromosome size has: 1) a positive relationship with genetic differentiation, genetic divergence, rate of lineage sorting in the contact zone, and proportion neutral evolution and 2) a negative relationship with genetic diversity and recombination rate.
Postnatal development of gut microbial activity and their importance for jejunal motility in piglets
Authors: Metzler-Zebeli Barbara U , Sener-Aydemir Arife , Sharma S , Lerch Frederike
Published: May 2021

Despite their anti-inflammatory properties, role in barrier function, absorption and microbial balance in the gut, knowledge on maturational and dietary effects on intestinal short-chain fatty acids (SCFA) in neonatal piglets is scarce. Moreover, little information exists whether SCFA and lactic acid (LA) modulates gut motility at this age. The present study aimed (1) to investigate the maturational changes in the SCFA profile with and without creep feeding of piglets in the first 3 wk of life; and (2) to examine the effects of SCFA and LA on muscle contractibility in jejunal tissue from neonatal piglets ex vivo. SCFA concentrations were measured in fecal samples of 52 piglets from 10 litters collected on days 2, 6, 13, and 20 of life using gas chromatography. Half of the litters were fed a commercial creep feed from day 10 of life. The organ bath system was used to test the effect of SCFA (acetate, propionate, butyrate, isobutyrate, valerate, isovalerate, and caproate) as well as of LA and the combination of LA and SCFA on muscle contractibility in piglet’s jejunum. Average daily gain of piglets was similar between groups before and after introduction of creep feed. SCFA were detectable in feces in relevant concentrations from day 2 of life and increased on day 6 in males by 3.0-fold and on day 13 in females by 1.6-fold but decreased again on day 20 in both sexes compared with day 2 (P < 0.05). Creep feeding reduced fecal SCFA by 0.6-fold on day 13 without largely modifying molar proportions, whereas it increased fecal SCFA by 0.8-fold on day 20 of life compared with the sow-reared only piglets (P < 0.05). Applying SCFA ex vivo increased the muscle contraction of the jejunum by 30% (P < 0.05). Likewise, addition of LA and the combination of LA and SCFA increased the jejunal muscle contractibility by 34.9% and 32.2%, respectively, compared with the muscle tension preaddition (P < 0.05). In conclusion, the present results for fecal SCFA in first days of life suggest high bacterial activity on milk components and emphasize the importance of SCFA for intestinal development and function. After a lag phase, creep feeding promotes fermentation in the distal colon, which may be beneficial for the gut homeostasis. Results further demonstrate the stimulating effect of SCFA and LA for jejunal motility, suggesting a role for mixing of digesta (segmentation) and digestion and absorption of nutrients as well as passage in the jejunum of neonatal piglets.
LC–MS-MS Analysis of Δ9-THC, CBN and CBD in Hair: Investigation of Artifacts
Authors: Scholz Clementine , Madry Milena M , Kraemer Thomas , Baumgartner Markus R
Published: May 2021

In forensic toxicology, high-performance liquid chromatography tandem mass spectrometry (LC–MS-MS) is increasingly used for the fast and sensitive measurement of a wide range of drugs. For our routine casework, a LC atmospheric pressure chemical ionization MS-MS method for the quantification of Δ9-tetrahydrocannabinol (Δ9-THC), cannabinol (CBN) and cannabidiol (CBD) in hair was established and fully validated. Separation was achieved using a Kinetex® C18 column (100 mm × 2.1 mm, 100 Å, 1.7 μm, Phenomenex) at a flow rate of 0.5 mL/min. Measurements were performed on a QTRAP 5500 mass spectrometer (Sciex, Darmstadt, Germany). Unexpected signals were observed in authentic THC-positive hair samples. First, a signal with a slightly shifted retention time of THC whose origin could be assigned to the isomer Δ8-THC was detected. Second, additional peaks exhibiting the same fragments as CBN and Δ9-THC but eluting at different retention times were detected. Spiking experiments and enhanced product ion scans pointed to the origin of these additional signals as result of in-source decarboxylation of Δ9-tetrahydrocannabinolic acid A (Δ9-THCA-A) into Δ9-THC and further partial oxidation of Δ9-THC into CBN, respectively. Positive findings of Δ9-THCA-A in hair have been shown to derive from external contamination; therefore, the herein described artifacts may be used as indirect markers for external contamination.
Modeling Rangeland Grasshopper (Orthoptera: Acrididae) Population Density Using a Landscape-Level Predictive Mapping Approach
Authors: Kistner-Thomas Erica , Kumar Sunil , Jech Larry , Woller Derek A
Published: May 2021

Since the mid-19th century, grasshoppers have posed a substantial threat to North American rangelands as well as adjacent croplands and have the potential to cost the economy millions of dollars in annual damages. The United States Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS) have gone to great lengths to ensure that rangeland grasshopper populations remain below an economic impact threshold across the western United States. However, current grasshopper forecasting efforts by the USDA are based solely on the previous year’s grasshopper density and do not take region-specific environmental factors (e.g., climate and topography) into account. To better understand the effects of climate and landscape heterogeneity on rangeland grasshopper populations, we assessed the relationship between grasshopper density survey data from across 56 sites between 2007 and 2017 for four counties in north central Wyoming with 72 biologically relevant geographic information system (GIS)-based environmental variables. A regression model was developed to predict mean adult grasshopper density from 2012 to 2016, which was then used to forecast grasshopper density in 2017. The best-fit predictive model selected using Akaike’s Information Criterion (AICc) explained 34.5% of the variation in mean grasshopper density from 2012 to 2016. October precipitation and past mean grasshopper density from 2007 to 2011 were among the best predictors of mean grasshopper density in 2012–2016. Our results also suggest that rangelands in central Sheridan County, southwest Johnson County, and southeast Washakie County are more prone to grasshopper outbreaks. Most importantly, this study demonstrated that both biotic and abiotic environmental variables influence grasshopper density and should be considered in future forecasting efforts.
Phototactic Behavioral Response of the Ectoparasitoid Beetle Dastarcus helophoroides (Coleoptera: Bothrideridae): Evidence for Attraction by Near-Infrared Light
Authors: Wang Qinzhao , Guo Zhou , Zhang Jiangtao , Chen Yuansheng , Zhou Jiaying , Pan Youliang , Liu Xingping
Published: May 2021

The ectoparasitoid beetle, Dastarcus helophoroides (Fairmaire) (Coleoptera: Bothrideridae), has been widely used as a biological control agent for many cerambycid beetles in China, Korea, and Japan. However, much less is known about its phototactic behavior to visual stimuli. In this paper, the phototactic behavioral response of D. helophoroides to 27 monochromatic lights and to nine illumination intensities of the most attractive light was evaluated using light-emitting diodes (LEDs) as light sources. The results showed that in dual choice between darkness and individual LED light, D. helophoroides adults exhibited a positively phototactic response to all wavelengths ranging from 300 to 860 nm. The near-infrared light (NIR, ranging from 700 to 760 nm) elicited stronger phototactic behavioral response, showing a preference for NIR wavelengths light. In paired choice among four preferred NIR lights, D. helophoroides adults displayed a significantly more favorable response to NIR light at 700 nm. Furthermore, the beetles expressed varying levels of sensitivity to illumination intensities from 1 to 600 lux under NIR light at 700 nm. The phototactic response was strongest at 7 lux and a statistically significant downward trend was found with increasing or decreasing the illumination intensities. These findings clearly demonstrate that D. helophoroides is a positively phototactic insect and its phototactic behavior is significantly influenced by light wavelength and illumination intensity, among which NIR light with peak wavelength at 700 nm and an intensity at 7 lux are most suitable in attracting D. helophoroides adults.
Effect of Cardinium Infection on the Probing Behavior of Bemisia tabaci (Hemiptera: Aleyrodidae) MED
Authors: Ying Liu , Baiming Liu , Hongran Li , Tianbo Ding , Yunli Tao , Dong Chu
Published: May 2021

Facultative endosymbionts can affect the growth, physiology, and behavior of their arthropod hosts. There are several endosymbionts in the invasive whitefly Bemisia tabaci Mediterranean (MED, Q biotype) that influence host fitness by altering stylet probing behavior. We investigated the probing behavior of B. tabaci MED infected with the facultative endosymbiont Candidatus Cardinium hertigii (Cardinium (Sphingobacteriales: Flexibacteraceae)). We generated genetically similar Cardinium-infected (C*+) and uninfected (C-) clonal sublines and analyzed the probing behavior of newly emerged adult on cotton (Malvales: Malvaceae), Gossypium hirsutum L., using electropenetrography (EPG). The C- subline demonstrated a longer duration of E2 (2.81-fold) and more events of E2 (2.22-fold) than the C*+ subline, indicating a greater level of sustained ingestion of plant phloem. These findings provide insight into the fitness costs (fitness of a particular genotype is lower than the average fitness of the population) of the Cardinium-infected B. tabaci.
Clinical outcomes of endoprosthetic reconstruction for proximal femoral resection
Authors: Kim Yongsung , Jeon Dae-Geun , Cho Wan Hyeong , Kong Chang-Bae , Song Won Seok
Published: May 2021

Introduction

The proximal femur is a common site for primary sarcomas and metastatic lesions. Although the early results of tumor prostheses are promising, the long-term results of reconstruction are unknown. The purpose of this study is to evaluate the prognostic factors affecting prosthesis survival and complications after proximal femoral resection and reconstruction.

Methods

We reviewed the results of 68 patients who underwent proximal femoral resection and reconstruction with a modular bipolar-type tumor prosthesis between 2005 and 2017. The mean follow-up was 55.6 months (range 6–172 months). There were 50 male and 18 female patients with a mean age of 41.5 years (range 11–80 years). Cumulative survival analysis was performed to analyze the risk factors of prosthesis survival. We also evaluated the complications after operation.

Results

Fourteen (21%) patients required further surgery at a mean 37 months post-operatively (range 5–125 months). There were three cases of infection (4%), six of local recurrence (9%), three of acetabular erosion (4%) and two of stem loosening (3%). The implant survival rates were 83.9% at 5 years and 59.8% at 10 years. Prosthesis survivals did not differ based on fixation method (P = 0.085), age (P = 0.329) or resection length (P = 0.61). Acetabular chondrolysis was identified in 18 (26%) patients and longer resection length (≥20 cm) showed a trend for risk of acetabular wear (P = 0.132).

Conclusion

The results of proximal femoral resection and reconstruction with a modular bipolar-type prosthesis were found to be acceptable with infection and local recurrence as short-term complications and loosening and acetabular erosion as long-term complications.
Relational Uncertainty Within Relational Turbulence Theory: The Bifactor Exploratory Structural Equation Model
Authors: Goodboy Alan K , Bolkan San , Brisini , Kellie , Solomon Denise Haunani
Published: May 2021

Relational uncertainty consists of self, partner, and relationship uncertainty, which are core parameters in relational turbulence theory (RTT). Advances in latent variable modeling allow researchers to examine the multidimensional construct as a bifactor model, including a general factor of relational uncertainty and residualized factors of self, partner, and relationship uncertainty. This advance is theoretically consequential because RTT maintains the importance of distinctions among the facets of relational uncertainty, even while empirical evidence demonstrates considerable overlap among them. In two data sets (college sample, N = 513; married sample, N = 354), competing measurement models specified Relational Uncertainty Scale items as a unidimensional confirmatory factor model, 3-factor independent clusters confirmatory factor model, 3-factor exploratory structural equation model (ESEM), bifactor confirmatory factor model, and bifactor-ESEM. The bifactor-ESEM provided the best fit in both samples, and bifactor statistics clarified how variance from the scale is partitioned to yield essential unidimensionality for the general factor of relational uncertainty, controlling for its residualized factors. Tests of a latent predictive model using a bifactor specification of relational uncertainty were consistent with RTT. Implications for testing communication theory using bifactor-ESEM are discussed in light of these findings.
Systematic Review and Meta-Analysis of Diagnostic Biomarkers for Pediatric Pneumonia
Authors: Gunaratnam Lourdes Cynthia , Robinson Joan L , Hawkes Michael T
Published: May 2021

Background

Pneumonia causes significant morbidity and mortality in children worldwide, especially in resource-poor settings. Accurate identification of bacterial etiology leads to timely antibiotic initiation, minimizing overuse, and development of resistance. Host biomarkers may improve diagnostic sensitivity and specificity. We assessed the ability of biomarkers to correctly identify bacterial pneumonia in children who present with respiratory distress.

Methods

A librarian-directed search was conducted of MEDLINE, EMBASE, CENTRAL, Global Health, the World Health Organization International Clinical Trials Registry Platform, and ClinicalTrials.gov to May 2020 with no language restriction. Included studies compared a diagnostic biomarker in children with bacterial pneumonia to those with nonbacterial respiratory distress.

Results

There were 31 observational studies of 23 different biomarkers. C-reactive protein (CRP), procalcitonin (PCT), white blood cell (WBC) count, and erythrocyte sedimentation rate (ESR) were the biomarkers with sufficient data for meta-analysis. Meta-analysis revealed that CRP and PCT best differentiated bacterial from viral pneumonia with CRP summary AUROC (area under the receiver operating characteristic curve) 0.71 (0.69-0.73), Youden index 53 mg/L, sensitivity 0.70 (0.68-0.78), and specificity 0.64 (0.58-0.68) and PCT summary AUROC 0.70 (0.67-0.74), Youden index 0.59 ng/mL, sensitivity 0.69 (0.65-0.77), and specificity 0.64 (0.60-0.68). WBC and ESR did not perform as well. Nineteen other inflammatory and immunologic biomarkers were identified including CRP/mean platelet value, neutrophil/leukocyte ratio, interleukin 6, and interferon-alpha, with sensitivities from 60% to 85% and specificities from 76% to 83%.

Conclusion

CRP and PCT performed better than WBC and ESR but had suboptimal sensitivity. Some less well-studied novel biomarkers appear to have promise particularly in combination.