bluuebunny/crossref_metadata_2025 huggingface dataset:
The Discrete Mathematical Charms of Paul Erdős
Authors: Chvátal Vašek
Published: August 2021

Paul Erdős published more papers during his lifetime than any other mathematician, especially in discrete mathematics. He had a nose for beautiful, simply-stated problems with solutions that have far-reaching consequences across mathematics. This captivating book, written for students, provides an easy-to-understand introduction to discrete mathematics by presenting questions that intrigued Erdős, along with his brilliant ways of working toward their answers. It includes young Erdős's proof of Bertrand's postulate, the Erdős-Szekeres Happy End Theorem, De Bruijn-Erdős theorem, Erdős-Rado delta-systems, Erdős-Ko-Rado theorem, Erdős-Stone theorem, the Erdős-Rényi-Sós Friendship Theorem, Erdős-Rényi random graphs, the Chvátal-Erdős theorem on Hamilton cycles, and other results of Erdős, as well as results related to his work, such as Ramsey's theorem or Deza's theorem on weak delta-systems. Its appendix covers topics normally missing from introductory courses. Filled with personal anecdotes about Erdős, this book offers a behind-the-scenes look at interactions with the legendary collaborator.
The Exception as the Rule: Negligent Hiring Liability, Structured Uncertainty, and the Rise of Criminal Background Checks in the United States
Authors: McElhattan David
Published: August 2021

The threat of negligent hiring lawsuits is thought to play an important role in the widespread use of criminal background checks among US employers. This article examines the construction of negligent hiring within the trade literature of the human resources (HR) field using a qualitative content analysis. While courts tend to view criminal record checks as unnecessary for occupations that do not carry foreseeable risks, the article finds that the HR field has broadly endorsed criminal record checks as the default practice for screening job candidates. The article argues that this divergence stems from the structured uncertainty of compliance under the common law tort of negligent hiring, which shapes organizational behavior in ways that defy the substantive clarity of relevant case law.
War Imprisonment and British Prison Reform
Authors: Weil Rachel
Published: August 2021

In 1756, the young John Howard set out for Portugal. His ship was taken by a privateer, and Howard became a prisoner of war in France. Twenty years later, he launched the movement for prison reform in Britain. Renaud Morieux challenges historians to more fully connect war imprisonment and the debates it engendered about prisoners’ rights to the emergence of prison reform in the 1770s and 1780s (p. 92). In this article, I take up that challenge. I suggest, however, that the connections are complex and twisted. Concerns about prisoners of war may have inspired prison reform, but they also made the project more confusing.
A change in clinical practice for aural foreign bodies – what we learnt from the coronavirus disease 2019 pandemic
Authors: Ho G C , Thind R , Yap D , Hunt A
Published: August 2021

Objective

This case series, conducted during the coronavirus disease 2019 pandemic, investigates the impact of leaving aural foreign bodies in situ for a prolonged period of time, including the risk of complications and success rates of subsequent removal attempts.

Method

A retrospective study of aural foreign body referrals over a six-month period was carried out.

Results

Thirty-four patients with 35 foreign bodies were identified (6 organic and 29 inorganic). The duration of foreign bodies left in situ ranged from 1 to 78 days. Four patients suffered from traumatic removal upon initial attempts. First attempts made by non-ENT specialists (68.8 per cent) all failed and were associated with a high risk of trauma (36.4 per cent).

Conclusion

Because of the coronavirus disease 2019 pandemic, this is the first case series to specifically investigate the relationship between the duration of aural foreign bodies left in situ and the risk of complications. Our data suggest that prolonged duration does not increase the incidence of complications.
One year on: assessing the impact of coronavirus disease 2019 on demand for semi-urgent ENT services
Authors: Allen H , Winstanley J , Stubington T J , Judd O
Published: August 2021

Objective

This study investigated how the coronavirus disease 2019 pandemic has impacted on presentations to ENT first-on-call services.

Methods

All appointments to a rapid access triage clinic from 1 June to 31 August in 2019 and 2020 were reviewed retrospectively and their reasons for consultation classified. A binomial proportion test was used to determine whether the proportions of consultations per presentation differed significantly between years. This analysis was repeated with the number of unique patients per presenting complaint.

Results

The proportions of nine reasons for consultation differed significantly between 2019 and 2020, including an increase in otitis media and nasal trauma presentations, and a decrease in otitis externa and tonsillitis presentations. Reattendances caused some variation in the frequency of certain diagnoses.

Conclusion

Our data suggest a shift in the presentations to first-on-call services, which may be a result of changes in patient behaviour and access to healthcare services.
Understanding curriculum design in the perceptions and practices of classroom music teachers in the lower secondary school in England
Authors: Anderson Anthony
Published: August 2021

Curriculum design is a domain that infrequently forms a discrete element of initial teacher training, or continuing professional development for music teachers in English secondary schools. Classroom music teachers, teaching Key Stage 3 (KS3) learners (11–14-year olds), are, however, required to design their own curriculum. Teachers are accountable to school leaders for curricula they implement, and the outcomes from their selected approaches. This article discusses classroom music curriculum practices and their significance in music education. The research project was conducted with music teachers from schools in the East and West Midlands of England, utilising questionnaires and semi-structured interviews. Research findings are conceptualised in a model of music curriculum activity. The research thereby facilitates discussion of unacknowledged complexities and tacit teacher planning practices in music curriculum design.
STRETCHING THE NET: MULTIDIMENSIONAL REGULARIZATION
Authors: Vives-i-Bastida Jaume
Published: August 2021

This paper derives asymptotic risk (expected loss) results for shrinkage estimators with multidimensional regularization in high-dimensional settings. We introduce a class of multidimensional shrinkage estimators (MuSEs), which includes the elastic net, and show that—as the number of parameters to estimate grows—the empirical loss converges to the oracle-optimal risk. This result holds when the regularization parameters are estimated empirically via cross-validation or Stein’s unbiased risk estimate. To help guide applied researchers in their choice of estimator, we compare the empirical Bayes risk of the lasso, ridge, and elastic net in a spike and normal setting. Of the three estimators, we find that the elastic net performs best when the data are moderately sparse and the lasso performs best when the data are highly sparse. Our analysis suggests that applied researchers who are unsure about the level of sparsity in their data might benefit from using MuSEs such as the elastic net. We exploit these insights to propose a new estimator, the cubic net, and demonstrate through simulations that it outperforms the three other estimators for any sparsity level.
Picking Places and People: Centralizing Provincial Governance in China
Authors: Lu Warren Wenzhi , Tsai Kellee S.
Published: August 2021

China's political system has been characterized by two institutions since the 1980s: an explicit “layer-by-layer administrative hierarchy” and the “appointment of cadres one level down.” There have, however, been two departures from these administrative practices. First, some provinces have “empowered prosperous counties” by placing them in a dual-reporting relationship with both prefecture-level cities and provinces. Second, some provinces have restored personnel control going “two levels down” by appointing key officials at the county and urban district levels of government. These deviations evolved as responses to China's GDP-centric policy environment during the early reform era. Based on field interviews and nationwide analysis of city-level personnel data, this article argues that such adaptations have generated unintended conflicts between provinces and prefecture-level cities. While prior studies of evolutionary change in China highlight the relationship between state and non-state actors, this study demonstrates how interactions among state actors themselves may fundamentally transform the dynamics of administrative governance.
Dealing with change: the Carthusians and Corpus Christi
Authors: DE COUL THOMAS OP
Published: August 2021

The Carthusian Order is known for its conservative attitude towards liturgy and music. This article will explore how this attitude played out in practice when the Carthusians were confronted with the introduction of a major new feast. Since its origins in the late eleventh century, the Order incorporated several new feasts in its calendar. These additions were normally made with a significant delay, and almost always without any new chants created for these feasts. The feast of Corpus Christi provides an interesting case study. Contrary to their habit, the Carthusians were apparently quick to adopt it, and they included most of the chants that were compiled and edited for this feast. In doing this, they took the Cibavit eos Mass and the Sacerdos in aeternum Office, most famously found in a late thirteenth-century libellus (F-Pnm, lat. 1143) as a point of departure. The Mass Propers were largely taken over, but small variations in the melodies raise interesting questions about how they were transmitted. By contrast, the office chants were thoroughly reordered and melodically edited in various ways, giving us a tangible sense of how Carthusians dealt with change.
Impact of atrial septal defect device size on biventricular global and regional function: a two-dimensional strain echocardiographic study
Authors: Alkhateeb Areej , Roushdy Alaa , Hasan-Ali Hosam , Kishk Yehia T. , El Sayegh Aya , Hassan Ayman K.M.
Published: August 2021

Objective:

In this study, we assessed the acute changes in biventricular longitudinal strain after atrial septal defect transcatheter closure and its relation to the device size.

Methods:

Hundred atrial septal defect patients and 40 age-matched controls were included. Echocardiography and strain study were performed at baseline and 24 hours and 1 month after the intervention. The study group was divided into two subgroups; group 1: smaller devices were used (mean device size = 1.61 ± 0.05 cm, n = 74) and group 2: larger devices were used (mean device size = 2.95 ± 0.07 cm, n = 26).

Results:

At baseline, there was a significant difference between the study group and controls as regards right ventricular global longitudinal strain with significant hyperkinetic apex (p = 0.033, p = 0.020, respectively). There was a significant immediate reduction in right ventricular global longitudinal strain (from −24.43 ± 0.49% to −21.62 ± 0.47%, p < 0.001), which showed insignificant improvement after 1-month follow-up. While only left ventricular global longitudinal strain increased after 1 month. Within 24 hours of device closure, all the basal- and mid-lateral segments strains and apical right ventricular strains showed a significant reduction. There was a significant negative correlation between the indexed large device size and an immediate change in the right ventricular global longitudinal strain (r = −0.425, p = 0.034).

Conclusion:

Significant right ventricular global longitudinal strain reduction starts as early as 24 hours after transcatheter closure, irrespective of the device size used. The rapid impact of closure was mainly on the biventricular basal and lateral segments and right ventricular apical ones, especially with the large sized atrial septal defect.
Implementation of a novel vocal cord dysfunction management pathway using the consolidated framework for implementation research
Authors: Merlo Greg , Suna Jessica M , McIntosh Amy , Jardine Karen , Kenny Louise , Orchard Jennifer , Wilson Mary , Alphonso Nelson
Published: August 2021

Every year in Australia over a thousand children who are born with congenital heart disease require surgical intervention. Vocal cord dysfunction (VCD) can be an unavoidable and potentially devastating complication of surgery for congenital heart disease. Structured, multidisciplinary care pathways help to guide clinical care and reduce mortality and morbidity. An implementation study was conducted to embed a novel, multidisciplinary management pathway into practice using the consolidated framework for implementation research (CFIR). The goal of the pathway was to prepare children with postoperative vocal cord dysfunction to safely commence and transition to oral feeding. Education sessions to support pathway rollout were completed with clinical stakeholders. Other implementation strategies used included adaptation of the pre-procedural pathway to obtain consent, improving the process of identifying patients on the VCD pathway, and nominating a small team who were responsible for the ongoing monitoring of patients following recruitment. Implementation success was evaluated according to compliance with pathway defined management. Our study found that while there were several barriers to pathway adoption, implementation of the pathway was feasible despite pathway adaptations that were required in response to COVID-19.
The effect of surgical technique, age, and Trisomy 21 on early outcome of surgical management of complete atrioventricular canal defect
Authors: Azzab Sherief , Samy Ahmed , Singab Hamdy , Zeinah Mohamed , Musollari Gledisa , Axiaq Ariana , Harky Amer , Tarek Ahmed , El Ghanam Mohamed
Published: August 2021

Background:

The optimal timing, surgical technique, and the influence of Trisomy 21 on the outcome of surgical repair of Complete Atrioventricular Canal Defect remains uncertain. We reviewed our experience in the repair of CAVC to identify the influence of these factors on operative outcomes.

Methods:

A prospective study included 70 patients, who underwent repair of CAVC at our institute between July, 2016 and October, 2019. Primary endpoint was mortality and the secondary endpoint was a degree of left atrioventricular valve regurgitation.

Results:

No significant difference was noted between patients operated on, at the first 6 months of age versus later, regarding mortality or LAVV regurgitation. Surgical repair by modified single-patch technique showed a significant reduction in bypass time (71.13 ± 13.507 min versus 99.19 ± 27.092 min, p-value = 0.001). Compared to closure of cleft only, posterior annuloplasty used for repair of LAVV resulted in significant reduction in the occurrence of post-operative valve regurgitation during the early period (LAVV 2 + 43 versus 7 %, p-value = 0.03) and at 6 months of follow-up (LAVV 2 + 35.4 versus 0 %, p-value = 0.01), respectively.

Conclusions:

Early intervention, in the first 6 months in patients with CAVC by surgical repair gives comparable acceptable results to later repair; Trisomy 21 was not found to be a risk factor for early intervention. Repair of common AV valve by cleft closure with posterior LAVV annuloplasty showed better results with a significant decrease in post-operative LAVV regurgitation and early mortality in comparison to the closure of cleft only.
Thinness, overweight and obesity among 6- to 17-year-old Malaysians: secular trends and sociodemographic determinants from 2006 to 2015
Authors: Mohamad Maria S , Mahadir Naidu Balkish , Kaltiala Riittakerttu , Virtanen Suvi M , Lehtinen-Jacks Susanna
Published: August 2021

Objective:

To examine secular trends and sociodemographic determinants of thinness, overweight and obesity among Malaysian children and adolescents from 2006 to 2015.

Design:

We used cross-sectional data from the National Health and Morbidity Surveys 2006, 2011 and 2015. Individuals were classified into pre- (6–9 years), early (10–13 years) and mid- (14–17 years) adolescence. BMI status was determined according to the International Obesity Task Force (IOTF) and WHO criteria, using measured height and weight. We analysed trends using log-binomial regression, by sex-age groups, stratified by sociodemographic factors (ethnicity, residential area, household size and household income), and accounting for the complex survey design. Associations between sociodemographic factors and prevalence of thinness and overweight (obesity included) in 2015 were assessed using log-Poisson regression.

Setting:

Nationwide population-based surveys, Malaysia.

Participants:

Eligible 6–17-year-olds from urban and rural residential areas (n 28 094).

Results:

The prevalence of thinness decreased from 2006 to 2015 (IOTF: boys from 22 % to 18 %, girls from 23 % to 19 %; WHO: boys from 9 % to 7 %, girls from 8 % to 6 %), while the prevalence of overweight increased (IOTF: boys from 20 % to 26 %, girls from 19 % to 24 %; WHO: boys from 25 % to 31 %, girls from 22 % to 27 %). These changes were statistically significant in most sex-age groups. Thinness and overweight co-existed in all sociodemographic subgroups, with variation in the prevalence estimates, but similar secular changes in most subgroups.

Conclusions:

Malaysia is facing a double burden of malnutrition at population level with a secular increase in overweight and obesity and a gradual decrease in thinness among 6–17-year-olds from varying sociodemographic backgrounds.
Association of long-term exposure to air pollution with chronic sleep deprivation in adults from 141 urban communities in South Korea: a community-level longitudinal study, 2008‒2016
Authors: Lee Whanhee , Seo Daeun , Myung Woojae , Prifti Kristi , Kang Cinoo , Jang Hyemin , Park Chaerin , Bell Michelle L. , Kim Ho
Published: August 2021

Aims

It has been well known that air pollution and sleep deprivation individually have impacts on human health; however, the association between the two has not been well researched. The aim of this study was to investigate this relationship at a community level.

Methods

We collected sleep outcomes from the Korean Community Health Survey between years of 2008 and 2016. The data contained 1 130 080 selected adults aged ⩾ 19 years, from 141 communities. As sleep outcomes, annual chronic sleep deprivation (% of people who sleep ⩽ 5 h per day on average) and average values of daily mean sleep duration were used. Community-specific annual averages of particulate matter with a diameter ⩽ 10 μm (PM10), nitrogen dioxide (NO2) and carbon monoxide (CO) were collected and then applied to a linear mixed effects model to estimate the association between air pollution over the past 4 years and sleep outcomes. Population density, green space, health behaviour, and gross regional domestic product per capita variables were considered as confounders in all mixed effect models.

Results

From the linear mixed effect models, we found that the chronic sleep deprivation % was positively associated with PM10 (0.33% increase with 95% CI 0.05–0.60; per 10 μg/m3) and NO2 (0.68% with 95% CI 0.44–0.92; per 10 ppm). Higher PM10 and NO2 were also associated with shorter sleep duration, with a reduction of 0.37 min (95% CI −0.33 to 1.07 min; per 10 μg/m3) and 2.09 min (95% CI 1.50–2.68 min; per 10 ppm), respectively. The associations between PM10 and sleep outcomes were higher in females than males and in the older age groups (⩾ 60-years) than in younger age groups (19–39 and 40–59 years). However, the association between NO2 and sleep outcomes were more higher in males than in females and in the younger age groups (19–39 years) than other age groups.

Conclusions

Our findings provide epidemiological evidence that long-term interventions to reduce air pollutions are anticipated to provide improvements in sleep deficiency.
Where Moons Are Made
Authors: Cartier Kimberly
Published: August 2021

The young, growing planet PDS 70 c has enough material swirling around it to make at least three Moon-sized moons.
Roadside Ditches Are Effective at Nitrogen Removal
Authors: Derouin Sarah
Published: August 2021

Researchers compared the nitrogen removal potential by microbes in ditches that drained forested, urban, and agricultural lands and discovered that roadside ditches are important areas for removing nutrients.
The Response of Daily and Sub‐Daily Extreme Precipitations to Changes in Surface and Dew‐Point Temperatures
Authors: Pérez Bello Alexis , Mailhot Alain , Paquin Dominique
Published: August 2021

Extreme precipitation events are expected to increase in frequency and intensity in the future climate, but the magnitude of these changes remains uncertain. The relationship between extreme precipitation and the surface temperature has been investigated to more robustly assess projected increases in extreme precipitation considering that projected temperature is more adequately simulated. Relationships between extreme precipitation (daily and sub‐daily) and surface air temperature (SAT) or surface dew‐point temperature (SDPT) are analyzed in this study using the 50‐members ensemble from the fifth version of the Canadian Regional Climate Model covering the Northeastern North America region over the period 1956–2099. Temperature‐precipitation scaling rates (TPSRs) were estimated using local SAT and SDPT seasonal anomalies as covariate over both periods for 2–100‐year extreme precipitation events and durations ranging from 1 to 24 h. Contrasting responses were obtained when using SAT or SDPT, especially in the southern part of the domain. Median scaling rates over the entire domain for SDPT were close to the Clausius‐Clapeyron scaling (°C) while they were much smaller for SAT and even negative in southern regions, showing that moisture availability is a key factor for these regions. TPSR based on SDPT is also more robustly constrained and can be used to estimate changes in short‐duration extreme precipitation in a future period from TPSR in the historical period over a large part of the domain.
circEVI5 acts as a miR-4793-3p sponge to suppress the proliferation of gastric cancer
Authors: Yan Meinan , Niu Liling , Liu Jing , Yao Yuan , Li Hui
Published: August 2021

Circular RNAs (circRNAs) are a novel class of endogenous noncoding RNAs (ncRNAs) with a covalently closed loop structure. Accumulating evidence shows that circRNAs play vital roles in the growth, metastasis, treatment and prognosis of various cancers. However, the detailed functions and underlying mechanisms of circEVI5 (hsa_circ_0013162) in gastric cancer (GC) remain undocumented. In this study, the expression levels and prognostic value of circEVI5 were validated in GC tissue samples by using qRT-PCR. circEVI5 was significantly downregulated in GC tissues and cells, and low circEVI5 expression was correlated with poor prognosis. Next, in vitro CCK-8 assay, EdU incorporation assay, PI staining cell cycle assay, and in vivo xenograft mouse models were conducted to assess the functions of circEVI5. Gain of function experiments indicated that circEVI5 could inhibit GC cell proliferation and retard the cell cycle. Moreover, bioinformatics prediction showed that circEVI5 binds to miR-4793-3p, while FOXO1 may be a target of miR-4793-3p. Pull-down assays, RNA immunoprecipitation (RIP) assays, luciferase assays, and western blot were used to confirm the interactions between circEVI5, miR-4793-3p, and FOXO1. Functional assays demonstrated that circEVI5 suppressed the proliferation of GC by sponging miR-4793-3p and increasing FOXO1 expression levels. In conclusion, our study demonstrated that circEVI5 can bind miR-4793-3p as a ceRNA to eliminate the negative regulation of FOXO1, therefore suppressing GC proliferation.
Compound 968 reverses adriamycin resistance in breast cancer MCF-7ADR cells via inhibiting P-glycoprotein function independently of glutaminase
Authors: Yang Ronghui , Guo Zihao , Zhao Yiliang , Ma Lingdi , Li Binghui , Yang Chuanzhen
Published: August 2021

Adriamycin (ADR) is a chemotherapeutic drug widely utilized to treat multiple types of cancers; however, the clinical efficacy of ADR is compromised due to the development of drug resistance in patients. The combination of drugs with ADR may provide a better therapeutic regimen to overcome this obstacle. Glutaminase (GLS) has been explored as a therapeutic cancer target, and its inhibition also results in increased sensitivity of tumor cells to chemotherapeutic agents. This study aimed to investigate whether GLS inhibition could reverse ADR resistance. We treated the ADR-resistant MCF-7 (MCF-7ADR) cells with a GLS inhibitor, compound 968 or CB-839, in combination with ADR. We found that compound 968, rather than CB-839, together with ADR synergistically inhibited the cell viability. These results indicated that compound 968 reversed ADR resistance in MCF-7ADR cells independently of GLS. Moreover, we modified the structure of compound 968 and finally obtained a compound 968 derivative, SY-1320, which was more potent than compound 968 in eliminating the drug resistance in MCF-7ADR cells. Furthermore, using drug affinity responsive target stability and streptavidin–biotin immunoprecipitation assays, we demonstrated that SY-1320 could specifically target P-glycoprotein (P-gp) and increase ADR accumulation through inhibition of P-gp, thereby resulting in cell death in MCF-7ADR cells. Together, our findings indicate that compound 968 or SY-1320 might be a promising drug for new combination chemotherapy in breast cancer to overcome the drug resistance.
Deep learning of contagion dynamics on complex networks
Authors: Murphy Charles , Laurence Edward , Allard Antoine
Published: August 2021

Forecasting the evolution of contagion dynamics is still an open problem to which mechanistic models only offer a partial answer. To remain mathematically or computationally tractable, these models must rely on simplifying assumptions, thereby limiting the quantitative accuracy of their predictions and the complexity of the dynamics they can model. Here, we propose a complementary approach based on deep learning where effective local mechanisms governing a dynamic on a network are learned from time series data. Our graph neural network architecture makes very few assumptions about the dynamics, and we demonstrate its accuracy using different contagion dynamics of increasing complexity. By allowing simulations on arbitrary network structures, our approach makes it possible to explore the properties of the learned dynamics beyond the training data. Finally, we illustrate the applicability of our approach using real data of the COVID-19 outbreak in Spain. Our results demonstrate how deep learning offers a new and complementary perspective to build effective models of contagion dynamics on networks.
Rhodaelectro-catalyzed access to chromones via formyl C–H activation towards peptide electro-labeling
Authors: Stangier Maximilian , Messinis Antonis M. , Oliveira João C. A. , Yu Hao , Ackermann Lutz
Published: August 2021

Chromones represent a privileged scaffold in medicinal chemistry and are an omnipresent structural motif in natural products. Chemically encoded non-natural peptidomimetics feature improved stability towards enzymatic degradation, cell permeability and binding affinity, translating into a considerable impact on pharmaceutical industry. Herein, a strategy for the sustainable assembly of chromones via electro-formyl C–H activation is presented. The rational design of the rhodaelectro-catalysis is guided by detailed mechanistic insights and provides versatile access to tyrosine-based fluorogenic peptidomimetics.
Closing the methane gap in US oil and natural gas production emissions inventories
Authors: Rutherford Jeffrey S. , Sherwin Evan D. , Ravikumar Arvind P. , Heath Garvin A. , Englander Jacob , Cooley Daniel , Lyon David , Omara Mark , Langfitt Quinn , Brandt Adam R.
Published: August 2021

Methane (CH4) emissions from oil and natural gas (O&NG) systems are an important contributor to greenhouse gas emissions. In the United States, recent synthesis studies of field measurements of CH4emissions at different spatial scales are ~1.5–2× greater compared to official greenhouse gas inventory (GHGI) estimates, with the production-segment as the dominant contributor to this divergence. Based on an updated synthesis of measurements from component-level field studies, we develop a new inventory-based model for CH4emissions, for the production-segment only, that agrees within error with recent syntheses of site-level field studies and allows for isolation of equipment-level contributions. We find that unintentional emissions from liquid storage tanks and other equipment leaks are the largest contributors to divergence with the GHGI. If our proposed method were adopted in the United States and other jurisdictions, inventory estimates could better guide CH4mitigation policy priorities.
Spectroscopic evidence for a large spot on the dimming Betelgeuse
Authors: Alexeeva Sofya , Zhao Gang , Gao Dong-Yang , Du Junju , Li Aigen , Li Kai , Hu Shaoming
Published: August 2021

During October 2019 and March 2020, the luminous red supergiant Betelgeuse demonstrated an unusually deep minimum of its brightness. It became fainter by more than one magnitude and this is the most significant dimming observed in the recent decades. While the reason for the dimming is debated, pre-phase of supernova explosion, obscuring dust, or changes in the photosphere of the star were suggested scenarios. Here, we present spectroscopic studies of Betelgeuse using high-resolution and high signal-to-noise ratio near-infrared spectra obtained at Weihai Observatory on four epochs in 2020 covering the phases of during and after dimming. We show that the dimming episode is caused by the dropping of its effective temperature by at least 170 K on 2020 January 31, that can be attributed to the emergence of a large dark spot on the surface of the star.
Activation pathway of a G protein-coupled receptor uncovers conformational intermediates as targets for allosteric drug design
Authors: Lu Shaoyong , He Xinheng , Yang Zhao , Chai Zongtao , Zhou Shuhua , Wang Junyan , Rehman Ashfaq Ur , Ni Duan , Pu Jun , Sun Jinpeng , Zhang Jian
Published: August 2021

G protein-coupled receptors (GPCRs) are the most common proteins targeted by approved drugs. A complete mechanistic elucidation of large-scale conformational transitions underlying the activation mechanisms of GPCRs is of critical importance for therapeutic drug development. Here, we apply a combined computational and experimental framework integrating extensive molecular dynamics simulations, Markov state models, site-directed mutagenesis, and conformational biosensors to investigate the conformational landscape of the angiotensin II (AngII) type 1 receptor (AT1 receptor) — a prototypical class A GPCR—activation. Our findings suggest a synergistic transition mechanism for AT1 receptor activation. A key intermediate state is identified in the activation pathway, which possesses a cryptic binding site within the intracellular region of the receptor. Mutation of this cryptic site prevents activation of the downstream G protein signaling and β-arrestin-mediated pathways by the endogenous AngII octapeptide agonist, suggesting an allosteric regulatory mechanism. Together, these findings provide a deeper understanding of AT1 receptor activation at an atomic level and suggest avenues for the design of allosteric AT1 receptor modulators with a broad range of applications in GPCR biology, biophysics, and medicinal chemistry.
COVID-19 spread, detection, and dynamics in Bogota, Colombia
Authors: Laajaj Rachid , De Los Rios Camilo , Sarmiento-Barbieri Ignacio , Aristizabal Danilo , Behrentz Eduardo , Bernal Raquel , Buitrago Giancarlo , Cucunubá Zulma , de la Hoz Fernando , Gaviria Alejandro , Hernández Luis Jorge , León Leonardo , Moyano Diane , Osorio Elkin , Varela Andrea Ramírez , Restrepo Silvia , Rodriguez Rodrigo , Schady Norbert , Vives Martha , Webb Duncan
Published: August 2021

Latin America has been severely affected by the COVID-19 pandemic but estimations of rates of infections are very limited and lack the level of detail required to guide policy decisions. We implemented a COVID-19 sentinel surveillance study with 59,770 RT-PCR tests on mostly asymptomatic individuals and combine this data with administrative records on all detected cases to capture the spread and dynamics of the COVID-19 pandemic in Bogota from June 2020 to early March 2021. We describe various features of the pandemic that appear to be specific to a middle income countries. We find that, by March 2021, slightly more than half of the population in Bogota has been infected, despite only a small fraction of this population being detected. The initial buildup of immunity contributed to the containment of the pandemic in the first and second waves. We also show that the share of the population infected by March 2021 varies widely by occupation, socio-economic stratum, and location. This, in turn, has affected the dynamics of the spread with different groups being infected in the two waves.
Optical N-invariant of graphene’s topological viscous Hall fluid
Authors: Van Mechelen Todd , Sun Wenbo , Jacob Zubin
Published: August 2021

Over the past three decades, graphene has become the prototypical platform for discovering topological phases of matter. Both the Chern $$C\in {\mathbb{Z}}$$
C
∈
Z
and quantum spin Hall $$\upsilon \in {{\mathbb{Z}}}_{2}$$
υ
∈

Z

2

insulators were first predicted in graphene, which led to a veritable explosion of research in topological materials. We introduce a new topological classification of two-dimensional matter – the optical N-phases $$N\in {\mathbb{Z}}$$
N
∈
Z
. This topological quantum number is connected to polarization transport and captured solely by the spatiotemporal dispersion of the susceptibility tensor χ. We verify N ≠ 0 in graphene with the underlying physical mechanism being repulsive Hall viscosity. An experimental probe, evanescent magneto-optic Kerr effect (e-MOKE) spectroscopy, is proposed to explore the N-invariant. We also develop topological circulators by exploiting gapless edge plasmons that are immune to back-scattering and navigate sharp defects with impunity. Our work indicates that graphene with repulsive Hall viscosity is the first candidate material for a topological electromagnetic phase of matter.
Four species of bacteria deterministically assemble to form a stable biofilm in a millifluidic channel
Authors: Monmeyran A. , Benyoussef W. , Thomen P. , Dahmane N. , Baliarda A. , Jules M. , Aymerich S. , Henry N.
Published: August 2021

Multispecies microbial adherent communities are widespread in nature and organisms, although the principles of their assembly and development remain unclear. Here, we test the possibility of establishing a simplified but relevant model of multispecies biofilm in a non-invasive laboratory setup for the real-time monitoring of community development. We demonstrate that the four chosen species (Bacillus thuringiensis,Pseudomonas fluorescens,Kocuria varians,andRhodocyclussp.) form a dynamic community that deterministically reaches its equilibrium after ~30 h of growth. We reveal the emergence of complexity in this simplified community as reported by an increase in spatial heterogeneity and non-monotonic developmental kinetics. Importantly, we find interspecies interactions consisting of competition for resources—particularly oxygen—and both direct and indirect physical interactions. The simplified experimental model opens new avenues to the study of adherent bacterial communities and their behavior in the context of rapid global change.
Tension-free Dirac strings and steered magnetic charges in 3D artificial spin ice
Authors: Koraltan Sabri , Slanovc Florian , Bruckner Florian , Nisoli Cristiano , Chumak Andrii V. , Dobrovolskiy Oleksandr V. , Abert Claas , Suess Dieter
Published: August 2021

3D nano-architectures presents a new paradigm in modern condensed matter physics with numerous applications in photonics, biomedicine, and spintronics. They are promising for the realization of 3D magnetic nano-networks for ultra-fast and low-energy data storage. Frustration in these systems can lead to magnetic charges or magnetic monopoles, which can function as mobile, binary information carriers. However, Dirac strings in 2D artificial spin ices bind magnetic charges, while 3D dipolar counterparts require cryogenic temperatures for their stability. Here, we present a micromagnetic study of a highly frustrated 3D artificial spin ice harboring tension-free Dirac strings with unbound magnetic charges at room temperature. We use micromagnetic simulations to demonstrate that the mobility threshold for magnetic charges is by 2 eV lower than their unbinding energy. By applying global magnetic fields, we steer magnetic charges in a given direction omitting unintended switchings. The introduced system paves the way toward 3D magnetic networks for data transport and storage.
Nanoscopic and in-situ cross-sectional observations of Li-based conversion coating formation using liquid-phase TEM
Authors: Kosari A. , Tichelaar F. , Visser P. , Taheri P. , Zandbergen H. , Terryn H. , Mol J. M. C.
Published: August 2021

Lithium salts have been proposed as promising environmentally friendly alternatives to carcinogenic hexavalent chromium-based inhibitors for the corrosion protection of aerospace aluminium alloys (AAs). Incorporated into organic coatings, lithium salts are released at damaged locations to establish a conversion layer in which distinct sublayers have different barrier characteristics. Thus, detailed knowledge on the sequence of formation events from the early stages of nucleation towards the final multi-layered arrangement is essential for developing and optimising lithium-leaching technology for protective coatings. Here, liquid-phase-transmission electron microscopy (LP-TEM) is employed to observe nanoscopic morphological evolutions in situ during the lithium-based conversion process of AA2024-T3. Thanks to dedicated preparation of delicate sandwiched TEM specimens allowing us to explore the events cross-sectionally, we provide real-time direct mechanistic information on the conversion process from the initiation to an advanced growth stage. In parallel, we perform supplementary ex situ SEM and TEM investigations to support and validate the LP-TEM findings. The unprecedented experimental approach developed and executed in this study provides an inspiring base for studying also other complicated surface conversion processes in situ and at the nanoscopic scale.
High-performance quantum entanglement generation via cascaded second-order nonlinear processes
Authors: Zhang Zichang , Yuan Chenzhi , Shen Si , Yu Hao , Zhang Ruiming , Wang Heqing , Li Hao , Wang You , Deng Guangwei , Wang Zhiming , You Lixing , Wang Zhen , Song Haizhi , Guo Guangcan , Zhou Qiang
Published: August 2021

In this paper, we demonstrate the generation of high-performance entangled photon-pairs in different degrees of freedom from a single piece of fiber pigtailed periodically poled LiNbO3 (PPLN) waveguide. We utilize cascaded second-order nonlinear optical processes, i.e., second-harmonic generation (SHG) and spontaneous parametric downconversion (SPDC), to generate photon-pairs. Previously, the performance of the photon-pairs is contaminated by Raman noise photons. Here by fiber-integrating the PPLN waveguide with noise-rejecting filters, we obtain a coincidence-to-accidental ratio (CAR) higher than 52,600 with photon-pair generation and detection rate of 52.36 kHz and 3.51 kHz, respectively. Energy-time, frequency-bin, and time-bin entanglement is prepared by coherently superposing correlated two-photon states in these degrees of freedom, respectively. The energy-time entangled two-photon states achieve the maximum value of CHSH-Bell inequality of S = 2.71 ± 0.02 with two-photon interference visibility of 95.74 ± 0.86%. The frequency-bin entangled two-photon states achieve fidelity of 97.56 ± 1.79% with a spatial quantum beating visibility of 96.85 ± 2.46%. The time-bin entangled two-photon states achieve the maximum value of CHSH-Bell inequality of S = 2.60 ± 0.04 and quantum tomographic fidelity of 89.07 ± 4.35%. Our results provide a potential candidate for the quantum light source in quantum photonics.
ACO2 clinicobiological dataset with extensive phenotype ontology annotation
Authors: Guehlouz Khadidja , Foulonneau Thomas , Amati-Bonneau Patrizia , Charif Majida , Colin Estelle , Bris Céline , Desquiret-Dumas Valérie , Milea Dan , Gohier Philippe , Procaccio Vincent , Bonneau Dominique , den Dunnen Johan T. , Lenaers Guy , Reynier Pascal , Ferré Marc
Published: August 2021

Pathogenic variants of the aconitase 2 gene (ACO2) are responsible for a broad clinical spectrum involving optic nerve degeneration, ranging from isolated optic neuropathy with recessive or dominant inheritance, to complex neurodegenerative syndromes with recessive transmission. We created the first public locus-specific database (LSDB) dedicated to ACO2 within the “Global Variome shared LOVD” using exclusively the Human Phenotype Ontology (HPO), a standard vocabulary for describing phenotypic abnormalities. All the variants and clinical cases listed in the literature were incorporated into the database, from which we produced a dataset. We followed a rational and comprehensive approach based on the HPO thesaurus, demonstrating that ACO2 patients should not be classified separately between isolated and syndromic cases. Our data highlight that certain syndromic patients do not have optic neuropathy and provide support for the classification of the recurrent pathogenic variants c.220C>G and c.336C>G as likely pathogenic. Overall, our data records demonstrate that the clinical spectrum of ACO2 should be considered as a continuum of symptoms and refines the classification of some common variants.
Multi-modal magnetic resonance imaging in a mouse model of concussion
Authors: To Xuan Vinh , Nasrallah Fatima A.
Published: August 2021

This data collection contains Magnetic Resonance Imaging (MRI) data, including structural, diffusion, stimulus-evoked, and resting-state functional MRI and behavioural assessment results, including acute post-impact Loss-of-Righting Reflex time and acute, subacute, and longer-term Neural Severity Score, and Open Field Behaviour obtained from a mouse model of concussion. Four cohorts with 43 3–4 months old male mice in total were used: Sham (n = 14, n = 6 day 2, n = 3 day 7, n = 5 day 14), concussion day 2 (CON 2; n = 9), concussion day 7 (CON 7; n = 10), concussion day 14 (CON 14; n = 10). The data collection contains the aforementioned MRI data in compressed NIFTI format, data sheets on animal’s backgrounds and behavioural outcomes and is made publicly available from a data repository. The available data are intended to facility cross-study comparisons, meta-analysis, and science reproducibility.
An annotated T2-weighted magnetic resonance image collection of testicular germ and non-germ cell tumors
Authors: Feliciani Giacomo , Mellini Lorenzo , Loi Emiliano , Piccinini Filippo , Galeotti Roberto , Sarnelli Anna , Parenti Gian Carlo
Published: August 2021

Testicular cancer is a rare tumor with a worldwide incidence that has increased over the last few decades. The majority of these tumors are testicular non-germ (TNGCTs) and germ cell tumors (TGCTs); the latter divided into two broad classes - seminomatous (SGCTs) and non-seminomatous germ cell tumors (NSGCTs). Although ultrasonography (US) maintains a primary role in the diagnostic workup of scrotal pathology, magnetic resonance imaging (MRI) has emerged as the imaging modality recommended for challenging cases, providing additional information to clarify inconclusive/equivocal US. In this work we describe and publicly share a collection of 44 images of annotated T2-weighted MRI lesions from 42 patients. Given that testicular cancer is a rare tumor, we are confident that this collection can be used to validate statistical models and to further investigate TNGCT and TGCT peculiarities using medical imaging features.
A dataset of distribution and diversity of blood-sucking mites in China
Authors: Meng Fan-Fei , Xu Qiang , Chen Jin-Jin , Ji Yang , Zhang Wen-Hui , Fan Zheng-Wei , Zhao Guo-Ping , Jiang Bao-Gui , Shi Tao-Xing , Fang Li-Qun , Liu Wei
Published: August 2021

Mite-borne diseases, such as scrub typhus and hemorrhagic fever with renal syndrome, present an increasing global public health concern. Most of the mite-borne diseases are caused by the blood-sucking mites. To present a comprehensive understanding of the distributions and diversity of blood-sucking mites in China, we derived information from peer-reviewed journal articles, thesis publications and books related to mites in both Chinese and English between 1978 and 2020. Geographic information of blood-sucking mites’ occurrence and mite species were extracted and georeferenced at the county level. Standard operating procedures were applied to remove duplicates and ensure accuracy of the data. This dataset contains 6,443 records of mite species occurrences at the county level in China. This geographical dataset provides an overview of the species diversity and wide distributions of blood-sucking mites, and can potentially be used in distribution prediction of mite species and risk assessment of mite-borne diseases in China.
Solubility of vitamin A in supercritical CO2: experimental study and thermodynamic modeling
Authors: Naikoo Gowhar Ahmad , Saeedi Zadegan Mohammad , Zamani Pedram Mona , Hassan Israr Ul , Ahmed Waqar , Yousefi Attar Golshan
Published: August 2021

One of the best methods of extracting Vitamin A, as a helper of the immune body system and vision, was measured in supercritical carbon dioxide (SC-CO2); Mole fractions were gained at practical conditions in which the temperature was in the range of 303–323 K and the pressure range was 90–235 bar, respectively. Moreover, four Equation of States [Soave–Redlich–Kwong, Peng–Robinson, Stryjek–Vera and Dashtizadeh–Pazuki–Taghikhani–Ghotbi (DPTG)] were compared with the experimental data. Also, the mixing rules of Van der Waals (vdW1 and vdW2) selected to correlate the solubility data of vitamin A. The outcomes indicate that each of EOSs coupled with vdW2, as a method of estimating the physicochemical and critical properties, were correlated with the solubility data of vitamin A in SC-CO2 with more accuracy, in comparison with vdW1. Among the cubic EOSs, the DPTG model with vdW2 generated the most suitable correlation with the percentage average absolute relative deviation (Average Absolute Relative Deviation%) of 6.