bluuebunny/crossref_metadata_2025 huggingface dataset:
A double‐modulation‐wave discontinuous pulse‐width‐modulation for dead‐time‐effect elimination and switching‐loss reduction in two‐level power converters
Authors: Yan Qingzeng , Zhou Zanrong , Wu Mingbo
Published: April 2023

High current qualities and high efficiencies are always two important characteristics for power converters. However, it is challenging to achieve the two targets simultaneously. In this paper, the dead‐time‐effect elimination pulse‐width‐modulation (PWM) for improving current qualities and the discontinuous PWM (DPWM) for reducing switching losses are combined, proposing a double‐modulation‐wave DPWM. An additional modulation wave is added, whose amplitude is adjusted according to the current polarity. By utilizing the added drive pulses in the current freewheeling stage, the proposed double‐modulation‐wave DPWM successfully reduces the dependence on the current polarities. The overmodulation phenomenon brought by the added modulation wave is analysed, which is proved to be negligible for achieving the maximum modulation index of 1.15. Finally, the effectiveness of the proposed double‐modulation‐wave DPWM is experimentally verified at a switching frequency of 40 kHz.
Clustering the properties of near-Earth objects: physico-dynamical links among NEOs
Authors: Deshapriya Jasinghege Don Prasanna , Perna Davide , Bott Nicolas , Hasselmann Pedro Henrique , Granvik Mikael , Dotto Elisabetta , Fulchignoni Marcello , Giunta Alessio , Perozzi Ettore , Ieva Simone , Petropoulou Vasiliki , Epifani Elena Mazzotta
Published: April 2023

Context. At present, near-Earth objects (NEOs) are being discovered at an ever-increasing rate. However, their physical characterisation is still significantly lagging behind. In particular, the taxonomic classification of newly discovered NEOs is of great importance with regard to improving our understanding of the population of NEOs.

Aims. In this context, our goal is to probe potential links between orbital properties of NEOs and their composition. We investigate whether we can make a reasonable guess about the taxonomic class of an NEO upon its discovery with a decent orbital accuracy.

Methods. We used a G-mode multivariate statistical clustering method to find homogeneous clusters in a dataset composed of orbital elements of NEOs. We adopted two approaches, using two sets of variables as inputs to the G-mode method. In each approach, we analysed the available taxonomic distribution of resulting clusters to find potential correlations with several unique parameters that distinctively characterise NEOs. We then applied a dynamical model on the same clusters to trace their escape regions.

Results. Approach 1 (A1) led us to obtain NEO clusters that can be linked to a primitive composition. This result was further strengthened by the dynamical model, which mapped outer-belt sources as escape regions for these clusters. We remark on the finding of a cluster akin to S-type NEOs in highly eccentric orbits during the same approach (A1). Two clusters, one with small NEOs in terrestriallike orbits and one with relatively high inclinations, were found to be common to both approaches. Approach 2 (A2) revealed three clusters that are only separable by their arguments of perihelion. Taken altogether, they make up the majority of known Atira asteroids.

Conclusions. For an NEO whose orbit is relatively well determined, we propose a model to determine whether the taxonomy of an NEO is siliceous or primitive if the orbital elements of the NEO fall within the presented combinations of inclination, eccentricity, and semi-major axis ranges.
Reverse-bias behaviour of thin-film solar cells: effects of measurement-induced heating
Authors: Heise Stephan J. , Komilov Asliddin , Richter Michael , Pieters Bart , Gerber Andreas , Neerken Janet
Published: April 2023

When a solar cell is subjected to a negative voltage bias, it locally heats up due to the deposited electrical power. Therefore, every investigation of cell characteristics in the negative voltage regime faces the challenge that the measurement itself changes the state of the cell in a way that is difficult to quantify: On the one hand, the reverse breakdown is known to be strongly temperature dependent. On the other hand, negative voltages lead to metastable device changes which are also very sensitive to temperature. In the current study, we introduce a new approach to suppress this measurement-induced heating by inserting time delays between individual voltage pulses when measuring. As a sample system we use thin-film solar cells based on Cu(In,Ga)Se2(CIGS) absorber layers. First we verify that with this approach the measurement-induced heating is largely reduced. This allows us to then analyse the impact of the heating on two characteristics of the cells: (i) the reverse breakdown behaviour and (ii) reverse-bias-induced metastable device changes. The results show that minimising the measurement-induced heating leads to a significant increase of the breakdown voltage and effectively slows down the metastable dynamics. Regarding the reverse breakdown, the fundamental tunneling mechanisms that are believed to drive the breakdown remain qualitatively unchanged, but the heating affects the quantitative values extracted for the associated energy barriers. Regarding the reverse-bias metastability, the experimental data reveal that there are two responsible mechanisms that react differently to the heating: Apart from a charge redistribution at the front interface due to the amphoteric (VSe–VCu) divacancy complex, the modification of a transport barrier is observed which might be caused by ion migration towards the back interface. The findings in this study demonstrate that local sample heating due to reverse-bias measurements can have a notable impact on device behaviour which needs to be kept in mind when developing models of the underlying physical processes.
Vertrauen schenken – Syndrom des hyperaktiven Beckenbodens
Authors: Henscher Ulla
Published: April 2023

Ein hyperaktiver Beckenboden kann Schmerzen im Beckenbereich verursachen und hängt nicht selten mit sexuellen, körperlichen und psychischen Traumata zusammen. Der Auszug aus dem Buch „Physiotherapie in der Gynäkologie“ macht deutlich, welchen Stellenwert ein vertrauensvolles Verhältnis besonders bei dieser Patientinnengruppe hat.
“Elastic” and “inelastic” twins and pinning of magnetic flux lines (vortices) in single crystals YBa2Cu3O7–x
Authors: Boyko Yu. I. , Bogdanov V. V. , Vovk N. R. , Komisarov A. O. , Du Junyi , Nazyrov Z. F. , Samoylov A. V. , Gevorkyan E. S. , Vovk R. V.
Published: April 2023

In this work, we studied the fixation of magnetic vortices (pinning effect) on “inelastic” and “elastic” twins, whose wedge-shaped peaks in the direction of twinning do not reach the crystal surface. The effectiveness of the “elastic” twins effect as pinning centers was studied by measuring of the critical transport current Jc in single crystals YBa2Cu3O7–x. The presented experimental data indicate that the “elastic” twins boundaries are effective pinning centers of the magnetic flux lines in single crystals of the compound under study. The main pinning centers of the vortices are dislocation clusters forming at the vertices of the “elastic” twins. The dislocation lines are located in the twin plane and, if the orientation of the magnetic vortices and dislocation lines coincide, the energy of the vortices decreases, the pinning force appears, fixing their location, which ultimately leads to an increase in the critical density of the transport electric current.
The study of homogeneity of the hexagonal Ti3AlC2 phase with inclusions of the titanium carbide
Authors: Grib A. , Petrushenko S. , Dukarov S. , Prikhna T. , Serbenyuk T.
Published: April 2023

Maps of spatial distributions of Ti, Al, and C on two surfaces of the Ti3AlC2 hexagonal phase (the so-called MAX phase) with inclusions of the TiC phase and Al2O3 were obtained by means of the energy-dispersive X-ray spectroscopy. Volume fractions of phases were 0.848, 0.107, and 0.045, respectively. The sample was cut from the synthesized tablet. One of the analyzed surfaces of the sample was the free outer surface of the tablet (surface 1), and another surface was the cut (surface 2). Histograms of the concentration distributions of elements were plotted. For both surfaces, histograms of all elements have Gaussian forms with mean values of about their stoichiometric concentrations in Ti3AlC2 and TiC phases. Histograms for the carbon have maxima at 34–36 at. %, which is close to the stoichiometric content of the carbon in the Ti3AlC2 MAX phase (33 at. %), and at about 50 at. % that corresponds to the stoichiometric concentration of the carbon in the TiC phase. However, Gaussian standard deviations from these mean values are large (up to 7 at. %), which proves the existence of th vacancies and interstitials of the carbon in phases. The histogram for the aluminum on surface 1 has an additional distribution near zero value of the concentration, and the histogram for carbon on surface 2 has an additional distribution near 27.7 at. %. Both found particularities can be explained by supposing that the outer surface of the original tablet cools down more rapidly than its inner parts.
Investigation of the temperature behavior of the vibrational spectrum of the (CuSO4)(C2H8N2) · 2H2O organometallic crystal by Raman spectroscopy
Authors: Vankevich A. V. , Gnezdilov V. P. , Taranova I. A.
Published: April 2023

In the paper, the temperature behavior of the vibrational spectrum of the ( CuS O 4 ) ( C 2 H 8 N 2 ) ⋅ 2 H 2 O crystal has been analyzed by Raman scattering. At a temperature of about 70 K the appearance of new lines was detected in the Raman spectra. The appearance of additional lines is associated with the fixation of the torsional vibration of the ethylenediamine chelate ring. Such a fixation testifies to the implementation of an order–disorder structural phase transition in these crystals. A model of the mechanism of the phase transition in the ( CuS O 4 ) ( C 2 H 8 N 2 ) ⋅ 2 H 2 O crystal involving the chelate ring of ethylenediamine is proposed.
Effect of deuteration on the vibrational spectrum of the Cu(en) (D2O)2SO4 crystal
Authors: Vankevich A. V. , Gnezdilov V. P. , Taranova I. A.
Published: April 2023

This work investigated the vibrational spectrum of the deuterated organometallic crystal Сu(еn) ( D 2 O ) 2 S O 4 in a wide range of frequencies and temperatures. Results indicated that deuteration leads to a change of hydrogen not only in the water molecule, but also in the N H 2 molecule of the ethylenediamine ring. It was found that deuteration of the crystal disrupts the phase transition observed in the pure crystal.
Detangling the detonation of combustible clouds
Authors: Patrick Chris
Published: April 2023

Numerical models simulate how clouds of fuel-air explosives form and detonate.
A case study on developing renewable battery energy storage
Authors: Johnson-Groh Mara
Published: April 2023

What can the experiences of the United States, China, Australia, and the United Kingdom tell us about developing renewable energy storage systems?
Red-emitting and antibacterial carbon dots for cellular imaging and skin wound healing
Authors: Karami Sara , Shamsipur Mojtaba , Barati Ali , Fartootzadeh Reza , Molaabasi Fatemeh , Alipour Mohsen , Radi Hamid Cheraghian
Published: April 2023

Carbon dots (CDs) as a new type of fluorescent nanomaterials have attracted considerable attention from researchers in chemistry, biology, and materials science. Here, we employed a hydrothermal method for synthesis of red-emitting and antibacterial CDs displaying an excitation-independent emission characteristic with a maximum emission intensity at 610 nm (pH 7.4). The synthesised CDs exhibited a high capability for bioimaging in HeLa cells, because of their negligible cytotoxicity and acceptable red photoluminescence. Moreover, the antibacterial activity of CDs against P. aeruginosa was studied and showed a minimum inhibitory concentration (MIC) of 256 μg ml−1. Further experimental results showed the high ability of the CDs to heal skin wounds in the rat model. According to the observations, wound healing in the presence of the CDs was calculated four days faster with 20.48% better performance than the control group.
Error estimates of a finite volume method for the compressible Navier–Stokes–Fourier system
Authors: Basarić Danica , Lukáčová-Medviďová Mária , Mizerová Hana , She Bangwei , Yuan Yuhuan
Published: April 2023

In this paper we study the convergence rate of a finite volume approximation of the compressible Navier–Stokes–Fourier system. To this end we first show the local existence of a regular unique strong solution and analyse its global extension in time as far as the density and temperature remain bounded. We make a physically reasonable assumption that the numerical density and temperature are uniformly bounded from above and below. The relative energy provides us an elegant way to derive a priori error estimates between finite volume solutions and the strong solution.
On the Diophantine equation 𝑈_{𝑛}-𝑏^{𝑚}=𝑐
Authors: Heintze Sebastian , Tichy Robert , Vukusic Ingrid , Ziegler Volker
Published: April 2023

Let

(

U
n

)

n
∈

N

(U_n)_{n\in \mathbb {N}}

be a fixed linear recurrence sequence defined over the integers (with some technical restrictions). We prove that there exist effectively computable constants

B
B

and

N
0

N_0

such that for any

b
,
c
∈

Z

b,c\in \mathbb {Z}

with

b
>
B

b> B

the equation

U
n

−

b
m

=
c

U_n - b^m = c

has at most two distinct solutions

(
n
,
m
)
∈

N

2

(n,m)\in \mathbb {N}^2

with

n
≥

N
0

n\geq N_0

and

m
≥
1

m\geq 1

. Moreover, we apply our result to the special case of Tribonacci numbers given by

T
1

=

T
2

=
1

T_1= T_2=1

,

T
3

=
2

T_3=2

and

T

n

=

T

n
−
1

+

T

n
−
2

+

T

n
−
3

T_{n}=T_{n-1}+T_{n-2}+T_{n-3}

for

n
≥
4

n\geq 4

. By means of the LLL-algorithm and continued fraction reduction we are able to prove

N
0

=
2

N_0=2

and

B
=

e

438

B=e^{438}

. The corresponding reduction algorithm is implemented in Sage.
Latent disease similarities and therapeutic repurposing possibilities uncovered by multi-modal generative topic modeling of human diseases
Authors: Kozawa Satoshi , Yokoyama Hirona , Urayama Kyoji , Tejima Kengo , Doi Hotaka , Takagi Shunki , Sato Thomas N
Published: April 2023

Motivation

Human diseases are characterized by multiple features such as their pathophysiological, molecular and genetic changes. The rapid expansion of such multi-modal disease-omics space provides an opportunity to re-classify diverse human diseases and to uncover their latent molecular similarities, which could be exploited to repurpose a therapeutic-target for one disease to another.

Results

Herein, we probe this underexplored space by soft-clustering 6955 human diseases by multi-modal generative topic modeling. Focusing on chronic kidney disease and myocardial infarction, two most life-threatening diseases, unveiled are their previously underrecognized molecular similarities to neoplasia and mental/neurological-disorders, and 69 repurposable therapeutic-targets for these diseases. Using an edit-distance-based pathway-classifier, we also find molecular pathways by which these targets could elicit their clinical effects. Importantly, for the 17 targets, the evidence for their therapeutic usefulness is retrospectively found in the pre-clinical and clinical space, illustrating the effectiveness of the method, and suggesting its broader applications across diverse human diseases.

Availability and implementation

The code reported in this article is available at: https://github.com/skozawa170301ktx/MultiModalDiseaseModeling

Supplementary information

Supplementary data are available at Bioinformatics Advances online.
Survey of current policies towards widening cervical screening coverage among vulnerable women in 22 European countries
Authors: Mallafré-Larrosa Meritxell , Ritchie David , Papi Ginevra , Mosquera Isabel , Mensah Keitly , Lucas Eric , Bøje Rikke Buus , Kirkegaard Pia , Andersen Berit , Basu Partha ,   the CBIG-SCREEN Consortium, Bardou Marc , Andersen Berit S , Kirkegaard Pia , Bøje Rikke Buus , Tranberg Mette , Legood Rosa , Sun Li , McKee Martin , Bell Sadie , Greenley Rachel , Foss Anna , Rossi Paolo Giorgi , Bartolini Letizia , Bonvicini Laura , Ghirottoo Luca , Iorio Giusy , Auzzi Noemi , Mantellini Paola , Lunet Nuno , Firmino-Machado João , Teixeira Margarida , Fernandes Ana , Amorim Mariana , Baía Inês , Uusküla Anneli , Tisler Anna , Baban Aadriana , Tăut Diana , Jiboc Nicoleta , Nicula Florian , Tolnai Alexandra , Moore Rebecca , Moore Vanessa , Basu Partha , Mosquera Isabel , Mensah Keitly , Lucas Eric , Kirkegaard Pia , Rochaix Lise , Fiorina Camilla , Todorova Irina , Panayotova Yulia , Kotzeva Tatyana , Ritchie David , Ros Comesana Helena , Mallafré-Larrosa Meritxel , Papi Ginevra , Dascher-Nadel Christiane
Published: April 2023

Background

This study aimed to investigate the status of cervical cancer screening (CCS) implementation in Europe by investigating national or regional policies towards broadening coverage of CCS amongst vulnerable subgroups of the population at high risk for CC.

Methods

A web-based survey was conducted between September 2021 and February 2022 with CCS programme managers and experts to identify and rank six population subgroups at high risk considered most vulnerable to CC and to map existing policies that addressed the coverage of CCS towards population sub-groups at risk.

Results

A total of 31 responses were received from experts covering 22 European countries. The results of this survey suggest that whilst many countries identify lower coverage of CCS amongst population subgroups at high risk of CC as a public health problem, few countries have developed dedicated policies towards broadening coverage among these subgroups. The six countries who reported having done so were concentrated in the Northern or Western European regions, suggesting the existence of geographical disparities within the continent. A key challenge in this respect is the difficulty to categorize subgroups of the target population; many individuals are burdened by intersectionality thereby resting in multiple categories, which may hinder the effectiveness of interventions targeted to reach specific subgroups.

Conclusion

A greater clarity on the conceptualization of vulnerability can help countries to develop and subsequently implement strategies to increase coverage to subgroups of the target population currently underserved with regards to CCS.
The ethical aspects of exposome research: a systematic review
Authors: Safarlou Caspar W , Jongsma Karin R , Vermeulen Roel , Bredenoord Annelien L
Published: April 2023

In recent years, exposome research has been put forward as the next frontier for the study of human health and disease. Exposome research entails the analysis of the totality of environmental exposures and their corresponding biological responses within the human body. Increasingly, this is operationalized by big-data approaches to map the effects of internal as well as external exposures using smart sensors and multiomics technologies. However, the ethical implications of exposome research are still only rarely discussed in the literature. Therefore, we conducted a systematic review of the academic literature regarding both the exposome and underlying research fields and approaches, to map the ethical aspects that are relevant to exposome research. We identify five ethical themes that are prominent in ethics discussions: the goals of exposome research, its standards, its tools, how it relates to study participants, and the consequences of its products. Furthermore, we provide a number of general principles for how future ethics research can best make use of our comprehensive overview of the ethical aspects of exposome research. Lastly, we highlight three aspects of exposome research that are most in need of ethical reflection: the actionability of its findings, the epidemiological or clinical norms applicable to exposome research, and the meaning and action–implications of bias.
The Safety of Dilation of Ileoanal Strictures With Mechanical or Balloon Dilation Is Similar Among Patients After Ileal Pouch–Anal Anastomosis
Authors: Darlington Kimberly , Wang Annmarie , Herfarth Hans H , Barnes Edward L
Published: April 2023

Background

Anastomotic strictures occur in up to 38% of patients after ileal pouch–anal anastomosis (IPAA). We sought to compare the safety, effectiveness, and durability of mechanical dilation using a Hegar dilator to endoscopic through-the-scope balloon dilation (EBD) among IPAA patients with a rectal or ileoanal anastomotic stricture.

Methods

We identified adult patients with an IPAA for ulcerative colitis (UC) who underwent a pouchoscopy between January 1, 2015, and December 31, 2019, at a single institution. We compared the effectiveness (median maximum diameter of dilation [MMD]), safety, and durability of mechanical and balloon dilation using standard statistical comparisons.

Results

A total 74 patients had a stricture at the ileoanal anastomosis and underwent at least 1 mechanical or balloon dilation. The MMD with mechanical dilation was 19 (interquartile range [IQR], 18-20) mm for the first dilation and 20 (IQR, 18-20) mm for the second and third dilations. With balloon dilation, the MMD was 12 (IQR, 12-18) mm for the first dilation, 15 (IQR, 12-16.5) mm for the second dilation, and 18 (IQR, 15-18.5) mm for the third dilation. Patients undergoing mechanical dilation experienced a longer duration to second dilation (median 191 days vs 53 days: P < .001), with no difference in complications such as bleeding or perforation noted.

Conclusions

Among patients with ileoanal and rectal strictures, mechanical and balloon approaches to dilation demonstrated similar safety profiles and effectiveness. Mechanical dilation with Hegar dilators appears to be an effective and safe approach to the treatment of distal strictures after IPAA.
Prevalence and predictors of infant and young child feeding practices in sub-Saharan Africa
Authors: Aboagye Richard Gyan , Seidu Abdul-Aziz , Ahinkorah Bright Opoku , Cadri Abdul , Frimpong James Boadu , Dadzie Louis Kobina , Budu Eugene , Eyawo Oghenowede , Yaya Sanni
Published: April 2023

Background

This study assessed the prevalence and predictors of minimum dietary diversity (MDD), minimum meal frequency (MMF), and minimum acceptable diet (MAD) in sub-Saharan Africa (SSA).

Methods

A sample of 87 672 mother–child pairs from the 2010–2020 Demographic and Health Surveys of 32 countries in SSA was used. Multilevel binary logistic regression analysis was carried out to examine the predictors of MDD, MMF, and MAD. Percentages and adjusted odds ratios (aORs) with a 95% confidence interval (CI) were used to present the findings.

Results

The prevalence of MDD, MMF, and MAD in SSA were 25.3% (95% CI 21.7 to 28.9), 41.2% (95% CI 38.8 to 43.6), and 13.3% (95% CI 11.6 to 15.0), respectively. Children aged 18–23 months were more likely to have MDD and MAD but less likely to have MMF. Children of mothers with higher education levels were more likely to have MDD, MMF, and MAD. Children who were delivered in a health facility were more likely to have MDD and MAD but less likely to have MMF.

Conclusions

Following the poor state of complementary feeding practices for infants and young children, the study recommends that regional and national policies on food and nutrition security and maternal and child nutrition and health should follow the internationally recommended guidelines in promoting, protecting, and supporting age-appropriate complementary foods and feeding practices for infants and young children.
Severe tooth loss and mortality risk: a population-based, longitudinal prospective study in a rural setting
Authors: Del Brutto Oscar H , Recalde Bettsy Y , Rumbea Denisse A , Mera Robertino M
Published: April 2023

Background

Information on the relationship between tooth loss and mortality among individuals living in rural settings is limited.

Methods

In this prospective cohort study, Atahualpa residents ≥40 y of age (n=933) were followed for a mean of 7.3±3.2 y to estimate mortality risk according to whether they had severe tooth loss (<10 remaining teeth).

Results

Overall, 151 individuals (16%) died, resulting in a crude mortality rate of 2.35 per 100 person-years of follow-up. Individuals with severe tooth loss were more likely to die (73/276) compared with those with mild–moderate tooth loss (78/657), after adjusting for relevant covariates (hazard ratio 1.45 [95% confidence interval 1.02 to 2.04]).

Conclusions

Severe tooth loss is associated with increased mortality in remote communities.
Leveraging natural language processing and geospatial time series model to analyze COVID-19 vaccination sentiment dynamics on Tweets
Authors: Ye Jiancheng , Hai Jiarui , Wang Zidan , Wei Chumei , Song Jiacheng
Published: April 2023

Objective

To develop and apply a natural language processing (NLP)-based approach to analyze public sentiments on social media and their geographic pattern in the United States toward coronavirus disease 2019 (COVID-19) vaccination. We also aim to provide insights to facilitate the understanding of the public attitudes and concerns regarding COVID-19 vaccination.

Methods

We collected Tweet posts by the residents in the United States after the dissemination of the COVID-19 vaccine. We performed sentiment analysis based on the Bidirectional Encoder Representations from Transformers (BERT) and qualitative content analysis. Time series models were leveraged to describe sentiment trends. Key topics were analyzed longitudinally and geospatially.

Results

A total of 3 198 686 Tweets related to COVID-19 vaccination were extracted from January 2021 to February 2022. 2 358 783 Tweets were identified to contain clear opinions, among which 824 755 (35.0%) expressed negative opinions towards vaccination while 1 534 028 (65.0%) demonstrated positive opinions. The accuracy of the BERT model was 79.67%. The key hashtag-based topics include Pfizer, breaking, wearamask, and smartnews. The sentiment towards vaccination across the states showed manifest variability. Key barriers to vaccination include mistrust, hesitancy, safety concern, misinformation, and inequity.

Conclusion

We found that opinions toward the COVID-19 vaccination varied across different places and over time. This study demonstrates the potential of an analytical pipeline, which integrates NLP-enabled modeling, time series, and geospatial analyses of social media data. Such analyses could enable real-time assessment, at scale, of public confidence and trust in COVID-19 vaccination, help address the concerns of vaccine skeptics, and provide support for developing tailored policies and communication strategies to maximize uptake.
Using Antibodies in Microscopy: A Guide to Immunohistochemistry. Part 1: Antibodies, Tissue Fixation, Embedding, and Sectioning
Authors: Guerin Christopher J
Published: April 2023

Immunohistochemistry (IHC) is the use of antibodies as probes to determine the localization of proteins in a cell or tissue sample. In microscopy, the technique has been in use since the 1940s by pathologists and research scientists. At first glance it appears to be a straightforward procedure. In practice, however, an IHC protocol has several steps where problems can occur, resulting in either false positive or false negative data. IHC can be used in both transmitted light and fluorescence microscopy, and it can be used in combinations to identify and mark multiple proteins of interest. While many IHC techniques have been published, a certain amount of confusion exists as to how to optimize IHC procedures. This series of three articles will describe the steps involved in IHC, the function of each step, and some variations that occur in specific protocols on differing cell and tissue types. It is hoped that a better understanding of these steps will help to guide users in determining the optimal conditions for carrying through IHC protocols.
Evolution of Linoleic Acid Biosynthesis Paved the Way for Ecological Success of Termites
Authors: Macháček Stanislav , Tupec Michal , Horáček Natan , Halmová Martina , Roy Amit , Machara Aleš , Kyjaková Pavlína , Lukšan Ondřej , Pichová Iva , Hanus Robert
Published: April 2023

Termites are dominant animals of tropical terrestrial ecosystems. Their success is due to their eusocial organization as well as their ability to digest dead plant tissues. While being extremely abundant, the termite diet is poor in crucial nutrients, such as fatty acids. Linoleic acid (LA) is a precursor for many vital biomolecules, and most animals depend on its dietary supply. Termites count among the exceptions known to produce LA de novo, presumably via the action of an unknown Δ12 fatty acyl desaturase (FAD) introducing the second double bond into monounsaturated oleic acid. Here, we search for the evolutionary origin of LA biosynthesis in termites. To this end, we compile the repertoire of FAD homologs from 57 species of termites and their closest relatives, the cockroaches, analyze FAD phylogeny, and identify a potential Δ12 FAD branch, which arose through duplication of a likely Δ9 FAD. We functionally characterize both paralogs and identify the Δ9 activity in the ancestral FAD-A1a and the Δ12 activity responsible for LA biosynthesis in FAD-A1b. Through the combination of homology modeling and site-directed mutagenesis, we pinpoint structural features possibly contributing to the distinct functions, regiospecificities, and substrate preferences of the two enzymes. We confirm the presence of both paralogs in all 36 studied species of the Blattoidea lineage (Blattidae, Lamproblattidae, Cryptocercidae, and termites) and conclude that we identified an evolutionary event important for the ecological success of termites, which took place in their cockroach ancestors roughly 160 My and remained conserved throughout termite diversification into 3,000 extant species.
Topological properties in an Aubry–André–Harper model with p-wave superconducting pairing
Authors: Xu Tong-Tong , Li Jia-Rui
Published: April 2023

We study the topological properties of the one-dimensional p-wave Aubry–André–Harper (AAH) model with periodic incommensurate potential and transition coupling. The calculation results show that due to co-influence of the incommensurate potential and modulation phase, three topological phases arise in different parameter regions: a topologically trivial phase, Su–Schrieffer–Heeger (SSH)-like topological phase, and Kitaev-like topological superconducting phase with Majorana zero modes. By evaluating the Andreev reflection conductance, we see that in the Kitaev-like phase, the quantized conductance plateau comes into being at the zero-bias limit, due to the occurrence of resonant Andreev reflection. In addition, when the disorder effect is incorporated, the SSH-like topology is modified sensitively and the degenerate topological states split, whereas the Kitaev-like topological phase is robust to weak disorder. Finally, we find that disorder can induce topological phase transition, i.e. from the topologically trivial phase to the topological phase. Based on these results, we believe that our findings have significance for studying the topological phase transition in a one-dimensional topological superconducting system. Also, it provides a feasible scheme for clarifying different topological phases.
The Value of Data Records
Authors: Galperti Simone , Levkun Aleksandr , Perego Jacopo
Published: April 2023

Many e-commerce platforms use buyers’ personal data to intermediate their transactions with sellers. How much value do such intermediaries derive from the data record of each single individual? We characterize this value and find that one of its key components is a novel externality between records, which arises when the intermediary pools some records to withhold the information they contain. Our analysis has several implications about compensating individuals for the use of their data, guiding companies’ investments in data acquisition, and more broadly studying the demand side of data markets. Our methods combine modern information design with classic duality theory and apply to a large class of principal-agent problems.
Air pollution and human endogenous retrovirus methylation in the school inner-city asthma intervention study
Authors: Reddam Aalekhya , Bollati Valentina , Wu Haotian , Favero Chiara , Tarantini Letizia , Hoxha Mirjam , Comfort Nicole , Gold Diane R , Phipatanakul Wanda , Baccarelli Andrea A
Published: April 2023

Human endogenous retroviruses (HERVs) are transposable genomic elements generally repressed through DNA methylation. HERVs can be demethylated and expressed in response to environmental stimuli. Therefore, more research is needed to understand the influence of environmental exposures on HERV methylation. Air pollutants are commonly linked with global hypomethylation, and as HERVs comprise of nearly 8% of repetitive elements in the human genome, our objective was to examine the association between air pollutant exposure and HERV methylation. We investigated 180 students with asthma participating in the School Inner-City Asthma Intervention Study, which evaluated the efficacy of classroom air filters and school-wide pest management on air pollutant/allergen exposure and asthma. Both air pollutants measured in classrooms and asthma outcomes assessed by surveys were collected pre- and post-intervention. Buccal swabs were also collected pre- and post-intervention, and methylation levels from 9 transposable genomic elements (HERV-E, -FRD, -K, -L, -R, -W, -9, and HRES and LINE1) were measured. Adjusting for relevant covariates, the overall air pollutant mixture was cross-sectionally associated with higher HERV-W and lower HERV-L and LINE1 methylation. Coarse PM was cross-sectionally associated with higher HERV-K methylation and CO2 with lower LINE1 methylation. These results suggest that exposure to air pollutants is associated with HERV-W and HERV-K hypermethylation and HERV-L and LINE1 hypomethylation in children with asthma. Future studies are needed to characterize the links between HERV methylation and possible adverse outcomes.
Changes in Burnout and Moral Distress Among Veterans Health Administration (VA) Physicians Before and During the COVID-19 Pandemic
Authors: Mohr David C. , Apaydin Eric A. , Li Brandon M. , Molloy-Paolillo Brianne K. , Rinne Seppo T.
Published: April 2023

Background

We investigated the impacts of workload, resources, organizational satisfaction, and psychological safety on changes in physician burnout and moral distress among physicians during the early pandemic.

Methods

We obtained national administrative and survey data on burnout, moral distress, organizational satisfaction, psychological safety, COVID-19 burden, and state-level restrictions for 11,877–14,246 Veterans Health Administration (VA) physicians from 2019 and 2020. We regressed the changes in burnout and moral distress on the changes in reasonable workload, appropriate job resources, organizational satisfaction, and psychological safety, controlling for COVID-19 burden and restrictions, and individual and medical center characteristics.

Results

Burnout and moral distress were not related to COVID-19 cases or restrictions but were reduced by improvements in workload, organizational satisfaction, and psychological safety.

Conclusions

Health systems should be conscious of factors that can harm or improve physician well-being, especially in the context of external stressors.
Evaluation of Surgical N95 Respirators Covered With Combinations of Masks and Face Shield
Authors: Powell Jeffrey B. , Quinn Tyler , Walbert Gary , Simons Jeremy
Published: April 2023

Objective

The aim of the study is to evaluate the metabolic demands and internal breathing environments when covering an N95 with a surgical mask, cloth mask, and/or FS.

Methods

Three N95 models approved by the National Institute for Occupational Safety and Health were evaluated under six covering conditions using the National Institute for Occupational Safety and Health Automated Breathing and Metabolic Simulator. All conditions used one trial with each N95 for six incremental 5-minute work rates. Inhaled oxygen and carbon dioxide concentrations, peak inhaled and exhaled pressures, and inhaled wet-bulb and dry-bulb temperatures were measured continuously and averaged across all work rates and covering conditions.

Conclusions

Results suggest that metabolic demands and internal breathing environments are significantly impacted by all combinations of coverings tested when compared to N95 only.
An Assessment of Faculty Perceptions of Wellness Needs and Strategies to Optimize Engagement With Wellness Resources in Academic Medicine
Authors: Pieri Matteo F. , Becker-Haimes Emily M. , Weiss Michal , Grabill Megan , Neergaard Rebecca , Bellini Lisa , Wolk Courtney Benjamin
Published: April 2023

Objective

Faculty at academic medical institutions are at increased risk for burnout. This study aimed to assess faculty perceptions of wellness needs and identify strategies to optimize engagement with individualized wellness resources.

Methods

Semistructured interviews were conducted with 37 faculty members in one US academic medical center.

Results

Participants identified significant barriers to achieving emotional health and wellness goals. Areas where participants identified needing the most support included interpersonal relationships, accountability for wellness goals, career support, financial resources, and mentorship. Most participants were unaware of all wellness resources available at their institution. Participants recommended regular marketing and emphasizing confidentiality of employer-sponsored programs. They also provided feedback on specific dissemination and marketing methods.

Conclusions

This research underscores the need for wellness resources for faculty and the importance of intentional dissemination of these resources to optimize uptake.
A case of abdominal abscess after simultaneous omentum intraomental bio-scaffold islet-kidney transplantation
Authors: Liu Zewen , Pei Guanghui , Cai Xiangheng , Zou Jiaqi , Ding Xuejie , Sun Peng , Liang Rui , Zhang Boya , Wang Shusen
Published: April 2023

Compared with patients who undergo renal and islet transplantation sequentially, simultaneous omentum intraomental bio-scaffold islet-kidney transplantation in patients with type 1 diabetes complicated by renal failure has the advantages of donor homologation, less trauma, lower cost, and easier acceptance by patients. Omentum intraomental bio-scaffold islet has been gradually applied in clinical practice, and rare clinical complications have been reported. Here we report a case of abdominal abscess associated with extended-spectrum β-lactamase in a patient who underwent simultaneous omentum intraomental bio-scaffold islet-kidney transplantation; the islet grafts remained partially functional after appropriate anti-infective treatment.
Inhibition of somatostatin enhances the long-term metabolic outcomes of sleeve gastrectomy in mice
Authors: Kleiman Doron , Arad Yhara , Azulai Shira , Baker Aaron , Bergel Michael , Elad Amit , Hefetz Liron , Israeli Hadar , Littor Mika , Permyakova Anna , Samuel Itia , Tam Joseph , Schyr Rachel Ben-Haroush , Ben-Zvi Danny
Published: April 2023

Bariatric surgery is an effective obesity treatment, leading to weight loss and improvement in glycemia, that is characterized by hypersecretion of gastrointestinal hormones. However, weight regain and relapse of hyperglycemia are not uncommon. Here, we investigated the role of somatostatin (Sst) in bariatric surgery outcomes using a mouse model of sleeve gastrectomy (SG). Sst knockout (sst-ko) mice fed with a calorie-rich diet gained weight normally, and had a mild favorable metabolic phenotype compared to heterozygous sibling controls, including elevated plasma levels of Glp1. Mathematical modeling of the feedback inhibition between Sst and Glp1 showed that Sst exerts its maximal effect on Glp1 under conditions of high hormonal stimulation, such as following SG. Obese sst-ko mice that underwent SG had higher levels of Glp1 compared with heterozygous SG-operated controls. Accordingly, SG-sst-ko mice regained less weight than controls and maintained lower glycemia months after surgery. Obese wild-type mice that underwent SG and were treated daily with a Sst receptor inhibitor for two months, had higher Glp1 levels, regained less weight, and improved glycemia compared to saline- treated SG-operated controls. Our results suggest that Sst signaling inhibition enhances and maintains the long-term favorable metabolic outcomes of bariatric surgery.
Minute virus of mice is oncolytic for pancreatic cancer cells with mesenchymal phenotype
Authors: Garcin P. , Lulka H. , Dusetti N. , Vienne M. , Buscail L. , Cordelier P.
Published: April 2023

Pancreatic cancer will soon become the second cause of death by cancer in Western countries. The main barrier to increase the survival of patients with this disease requires the development of novel and efficient therapeutic strategies, that better consider tumor biology. Oncolytic viruses are quickly moving toward the forefront of medicines for the management of cancer. Among them, the fibrotropic minute virus of mice prototype (MVMp) preferentially infects migrating and undifferentiated cells, that highly resemble poorly differentiated, basal-like, pancreatic tumors showing the worst clinical outcome. Thus, we hypothesized that MVMp may specifically target the most aggressive subtype of pancreatic cancer cells. We report here that MVMp specifically infects, replicates in and kills pancreatic cancer cells from murine and human origin with a mesenchymal, basal-like profile, while sparing cancer cells with an epithelial phenotype.In vivo, MVMp shows oncolytic activity in experimental tumors with mesenchymal phenotype only, and shows increased antitumoral efficacy in immune competent models. Collectively, we demonstrate herein for the first time that MVMp is specific and oncolytic for pancreatic tumors with mesenchymal, basal-like profile, paving the way for precision medicine opportunities for the management of the most aggressive and lethal form of this disease.
Students’ psychological state and its associated factors during an outbreak of COVID-19 in Pakistan: a web-based survey
Authors: Ali Naureen Akber , Feroz Anam , Akber Noshaba , Khoja Adeel
Published: April 2023

Purpose

Coronavirus disease 2019 (COVID-19) pandemic has led to unprecedented mental health repercussions in the lives of every individual including university students. Therefore, study on students’ psychological state and its associated factors during the pandemic are of importance. This study aims to discuss the aforementioned issue.

Design/methodology/approach

An online survey was done on a total of 207 university students of Pakistan to collect information on socio-demographic characteristics, concerns or fears amidst COVID-19 and mental distress. Validated tools; Perceived Stress Scale (PSS), Generalized Anxiety Disorder Scale (GAD-7) and Patient Health Questionnaire (PHQ-9)-Depression were used to assess stress, anxiety and depression, respectively.

Findings

Around 14% of the university students were experiencing severe stress and anxiety, while 8.2% had severe depression. The authors found that stress among university students was related to psychiatric illness or symptoms (OR = 5.1: 1.1, 22.9) and unpredictability due to the pandemic (OR = 3.7: 1.2, 11.2). The significant determinants of anxiety were psychiatric illness/symptoms (OR = 6.6: 3.4, 12.9), implementation of public health measures (OR = 3.7: 1.1, 11.6), employed mothers (OR = 2.4: 1.1, 5.0) and lack of support from university administration (OR = 2.2: 1.0, 5.0). While the factors associated with depression included psychiatric illness or symptoms (OR = 8.4: 3.3, 21.5), unpredictability due to pandemic (OR = 6.8: 2.2, 20.7), impaired social support system (OR = 3.7: 1.3, 10.4) and studying without a scholarship (OR = 2.1: 1.0, 4.4).

Research limitations/implications

These findings call for an urgent need to develop appropriate interventions and educational programs that could address the psychological needs of students.

Practical implications

The study directs the role of university and faculty in dealing the mental health needs of the student in COVID-19 pandemic time.

Social implications

Educational programs are important that could address the psychological needs of students in COVID-19 pandemic.

Originality/value

University students reported mental distress during COVID-19 pandemic which shows that younger people are at risk of COVID-19 repercussions. Moreover, several stressors (i.e. impaired social support system and lack of support from universities) were revealed that could be mitigated by implementing appropriate strategies.
How to identify influential content: Predicting retweets in online financial community
Authors: He Dandan , Yao Zhong , Zhao Futao , Wang Yue
Published: April 2023

Purpose

Retail investors are prone to be affected by information dissemination in social media with the rapid development of Web 2.0. The purpose of this study is to recognize the factors that may impact users' retweet behavior, namely information dissemination in the online financial community, through machine learning techniques.

Design/methodology/approach

This paper crawled data from the Chinese online financial community (Xueqiu.com) and extracted author-related, content-related, situation-related, stock-related and stock market-related features from the dataset. The best information dissemination prediction model based on these features was determined by evaluating five classifiers with various performance metrics, and the predictability of different feature groups was tested.

Findings

Five prevalent classifiers were evaluated with various performance metrics and the random forest classifier was proven to be the best retweet prediction model in the authors’ experiments. Moreover, the predictability of author-related, content-related and market-related features was illustrated to be relatively better than that of the other two feature groups. Several particularly important features, such as the author's followers and the rise and fall of the stock index, were recognized in this paper at last.

Originality/value

This study contributes to in-depth research on information dissemination in the financial domain. The findings of this study have important practical implications for government regulators to supervise public opinion in the financial market.