bluuebunny/crossref_metadata_2025 huggingface dataset:
Microstructure, electromechanical hysteresis and polarization characteristics of solid solutions of the system (Na, K, Cd0.5) NbO3
Authors: Moysa M O , Andryushin K P , Shilkina L A , Nagaenko A V , Andryushina I N , Reznichenko L A
Published: February 2021

The phase diagram of the system (1-x-y) NaNbO3 – xKNbO3 – yCdNb2O6 (y=0.25, x=0.05÷0.20) is constructed. The agreement between the microstructure and the phase diagram of the system is demonstrated. A decrease in the polarization characteristics up to the phase transition temperature is detected. The formation of extrema d33
(E) in the region of the inflection point on the ascending branch of the half-period S33
is revealed. A correlation has been established between the internal structure (crystalline, domain, grain, defect), fundamental electromechanical and polarization properties for solid solutions of the studied system.
Features of protolytic reactions in the ground and exited states in the presence of cationic polyelectrolyte
Authors: Mugabutaeva A S , Naumova A O , Melnikov P V , Zaytsev N K
Published: February 2021

Protolytic reactions in the ground and excited states for 2-naphthol and its sulfo derivatives were studied. It was revealed that in the presence of cationic polyelectrolyte, the acidity constant of the protolytic reaction in the ground state shifts to a more acidic region. It was also found that the value of the shift depends on the number of sulfo substituents in 2-naphthol derivatives. It reaches 1.2 units for the disodium salt of 2-naphthol-3,6,8-trisulfonic acid. At the same time, no significant effect of the polyelectrolyte on the acidity constant in the excited state pKa* was observed, and the photoprotolytic reaction proceeds in the same way as for an unimmobilized substance.
Size Effects and Mechanisms in the Friction and Wear Processes of Ceramics Based on Zirconium Dioxide
Authors: Pirozhkova T S , Zhigachev A O , Korenkov V V , Tyurin A I
Published: February 2021

This paper presents a study of the tribological properties of ceramics based on ZrO2 stabilized with CaO in a ceramic-ceramic friction pair. The influence of the scale factor on the coefficient of friction in the micro- and nanoscale is established. A qualitative correlation of the theoretical and experimental curves is shown for friction coefficient dependence on the body-counterbody contact force. Friction and wear micromechanisms at a micro- and nanoscale are proposed for the investigated TZP ceramics.
Formation of high-entropy alloy by methods of ion-plasma technologies
Authors: Prokopenko N A , Petrikova E A , Shugurov V V , Petykevith M S , Ivanov Yu F , Uglov V V
Published: February 2021

Multi-element equiatomic single-phase thermodynamically stable substitutional solid solutions (high-entropy alloys) have a unique combination of mechanical, tribological, physical and other properties. The purpose of this research is to develop an ion-plasma method for the formation of high-entropy alloys. A method for the formation of high-entropy alloys has been developed, which consists in the deposition of a multi-element metal plasma on a substrate in a vacuum. Plasma is formed by vacuum-arc plasma-assisted simultaneous independent sputtering of the cathodes of the selected elements. The modes allowing synthesizing thin Ti-Al-Nb-Zr films with a composition close to equiatomic were revealed. The presence of droplet fraction particles of various elemental composition in the films was found. It is shown that the phase composition of the films depends on the concentration of elements in the plasma.
Studies of water treatment influence on the structure of vein quartz from shungite rocks
Authors: Rigaeva Y L , Rozhkova N N , Ekimova T A
Published: February 2021

The article presents the results of the research of the structure and composition of one of the morphological varieties of quartz – vein quartz of shungite rocks from Zazhogino deposit of Karelia and a reference quartz sample. The values of the crystal lattice parameters were determined by full-profile analysis (Rietveld method). Coherent scattering region (CSR) for vein quartz samples are determined using the Debye-Scherrer formula after applying the background subtraction function. The influence of water treatment on the content of impurity elements in samples of vein quartz was also studied. The most common impurity elements in natural vein quartz samples, such as Al, Na, Li and Ge, are identified. It is shown that water treatment is effective for reducing the content of impurity elements and obtaining the minimum size of vein quartz crystallites.
Dislocation structure and phase composition of Ti13Nb13Zr after high-pressure torsion
Authors: Rudenya E A , Ivanov I V , Ognev A Yu , George A M
Published: February 2021

The approach based on synchrotron X-ray diffraction was applied in this research to investigate the dislocation and phase structures of severely deformed disk of Ti13Nb13Zr alloy. It was found, that the final structure of the material is inhomogeneous along the disk diameter. The local area of highest dislocation density of α′-phase matches with the zone of passed deformation-induced phase transformations.
Deformation of silumin subjected to a pulsed electron beam treatment
Authors: Rygina M E , Ustinov A M , Petrikova E A , Klopotov A A , Ivanov Yu F , Teresov A D , Abzaev Yu A , Loskutov L M , Volokitin G G
Published: February 2021

Using a virtual extensometer, it was found that irradiation with a pulsed electron beam (18 keV, 15 J/cm2, 200 μs, 3 pulses, 0.3 s−1) leads to an increase in the strength properties of the hypoeutectic silumin samples by 30%. The deformation curves in the coordinates «σ-ε» and «σ - √ε» did not reveal inflection points that characterize the stages of deformation transformation of the material. This indicates that the transitions from stage to stage in this class of materials are blurred.
The Investigation of the Structure and Properties of Nonwoven Fibrous Materials Based on Polyhydroxybutyrate Biopolymer
Authors: Tyubaeva P M , Zykova A K , Morokov E S , Olkhov A A , Podmasteriev V V , Popov A A , Iordanskii A L
Published: February 2021

Currently, the development and research of nonwoven medical fibrous materials based on biopolymers is an area of a great practical interest. One of the most promising methods for producing nonwoven materials with a highly developed surface is electrospinning (ES). In the article, the possibility of effective sterilization of ultrathin fibers based on polyhydroxybutyrate (PHB) by the ozone treatment was considered. The purpose of this work was to establish the interrelation between changes in the ES process and accompanying changes in the supramolecular structure, morphology, physical and mechanical properties of the fibrous materials based on PHB.
Plant extract assisted synthesis of reduced graphene oxide sheet and the photocatalytic performances on cationic and anionic dyes to decontaminate wastewater
Authors: Ghosh Sanjukta , Das Piu , Baskey (Sen) Moni
Published: February 2021

Green synthesis of reduced graphene oxide (RGO) has gained momentum over chemical methods due to its environmental compatibility. The present study deals with the green synthesis of the RGO sheet using the bark extract of Alstonia scholaris by the simple heating method in less time duration. Different characterizations such as x-ray diffraction (XRD), ultraviolet-visible (UV-Vis) spectroscopy, Fourier-transform infrared (FTIR) spectroscopy confirm the formation of RGO and the transmission electron microscopy (TEM) study shows that the synthesized material is a few-layered RGO sheet. The result of the photoluminescence (PL) study explores the partial reduction of graphene oxide (GO). The photocatalytic activities of the synthesized product were investigated via photo-degradation of methylene blue (MB) and methyl orange (MO). The results show that the synthesized RGO is more fruitful in cationic dye (MB) degradation than that of anionic dye (MO) depending on the electrostatic interaction between RGO and the dyes. The rate of photocatalytic performance of the nanocomposite on MB dye is 40 times greater than that of MO dye.
Preparation and properties of controllable aluminum foam
Authors: Sun Leilei , Wang Yanli , Wang Lucai , Wang Fang , Xu Hong , Huang Wenzhan , You Xiaohong
Published: February 2021

As an important method for preparing aluminum foam, space holders have the advantages of simple preparation process, controllable porosity, high operation safety, easy to realize the large-scale production and so on. In this paper, sodium thiosulfate (Na2S2O3) is selected as the new raw material for spacer to replace the traditional spacer (such as urea and salt), which is prepared by melting, injecting into the mold and solidifying. Three kinds of spherical spacer with different diameters were modified, and aluminum foams with three porosity (65%, 70% and 75%) and three pore sizes (Ø2mm, Ø3mm and Ø4mm) were prepared by compaction, dissolution and sintering. The results of metallographic analysis of aluminum foam sintered sample show that the aluminum powder particles bond closely above 600 °C. The quasi-static compression results show that the interaction between aluminum matrix materials and pore structure affects the mechanical properties of foamed aluminum, and the interaction between porosity and pore size affects the mechanical properties of foamed aluminum.
Oblique propagation of nonlinear ion-acoustic cnoidal waves in magnetized electron–positron–ion plasmas with nonextensive electrons
Authors: KHALID Muhammad , ULLAH Ghufran , KHAN Mohsin , AHMAD Sheraz , NABI Sardar , KHAN Daud
Published: February 2021

Theoretical investigation of nonlinear electrostatic ion-acoustic cnoidal waves (IACWs) is presented in magnetized electron–positron–ion plasma with nonextensive electrons and Maxwellian positrons. Using reductive perturbation technique, Korteweg–de Vries equation is derived and its cnoidal wave solution is analyzed. For given plasma parameters, our model supports only positive potential (compressive) IACW structures. The effect of relevant plasma parameters (viz., nonextensive parameter q, positron concentration p, temperature ratio σ, obliqueness l
3) on the characteristics of IACWs is discussed in detail.
Electric-field induced fluctuations in laser generated plasma plume
Authors: AHMED Rizwan , JABBAR Abdul , UMAR Zeshan Adeel , BAIG Muhammad Aslam
Published: February 2021

The effect of an external electric field on laser-generated plasma has been studied. It is observed that the laser-generated plasma can be used for the ignition of a spark in the presence of a low voltage external electric field. An eight-fold emission intensity enhancement in Cu I spectral lines are measured as compared to the signal intensity in the absence of an external electric field. The plasma parameters remain the same initially, up to a few microseconds after the generation of plasma, and this feature makes it more interesting for the quantitative analysis of any sample using laser induced breakdown spectroscopy (LIBS). In the presence of an external electric field, fluctuations (contraction and expansion) in the laser-generated plasma are observed which increase the plasma decay time and consequently result in enhanced signal intensity.
Multiple current peaks and spatial characteristics of atmospheric helium dielectric barrier discharges with repetitive unipolar narrow pulse excitation
Authors: ZHOU Xiangyu , WANG Qiao , DAI Dong , HUANG Zeen
Published: February 2021

Atmospheric dielectric barrier discharges driven by repetitive unipolar narrow pulse excitation are investigated numerically by using one-dimensional fluid models. The one-dimensional simulation focuses on the effects of applied voltage amplitude, pulse repetition frequency, gap width and γ coefficient on the multiple-current-pulse (MCP) discharge. The results indicate that the MCP behavior will lead to the stratification of electron density distribution in axial direction. Traditional MCP manipulating methods, such as reducing the applied voltage amplitude, increasing the applied voltage frequency, adjusting the gap width, cannot regulate MCPs exhibiting in this work. Further analyses reveal that the increasing electric field of the cathode fall region is the basis for the emergence of MCP behavior.
Occupational Exposure to Second-Hand Tobacco Smoke: Development of a Job Exposure Matrix
Authors: Dobson Ruaraidh , Demou Evangelia , Semple Sean
Published: February 2021

Exposure to second-hand tobacco smoke (SHS) in the workplace has been largely controlled in most workplaces in many countries that have adopted smoke-free laws and regulations. Workers in offices, bars, restaurants, and many other settings have experienced substantial reductions in the frequency and intensity of their exposure to SHS. While current exposure to SHS of most non-smoking adults arises from living with a smoker there are likely to be some jobs where non-negligible exposure to SHS continues to occur. This study describes the development of a simple job exposure matrix (JEM) for SHS exposure for the UK working population in 2020 and identifies that at least 1.04 million workers are likely to be exposed to SHS while performing their job. Occupations with the highest frequency and intensity of exposure include those where workers carry out work tasks in private, domestic settings: including care workers and home carers. This SHS-JEM provides a novel method for assessing occupational exposure to SHS in other countries, and can act as a tool to identify priorities for policies to protect those workers who continue to be at risk from SHS.
Deep embedded clustering with multiple objectives on scRNA-seq data
Authors: Li Xiangtao , Zhang Shixiong , Wong Ka-Chun
Published: February 2021

In recent years, single-cell RNA sequencing (scRNA-seq) technologies have been widely adopted to interrogate gene expression of individual cells; it brings opportunities to understand the underlying processes in a high-throughput manner. Deep embedded clustering (DEC) was demonstrated successful in high-dimensional sparse scRNA-seq data by joint feature learning and cluster assignment for identifying cell types simultaneously. However, the deep network architecture for embedding clustering is not trivial to optimize. Therefore, we propose an evolutionary multiobjective DEC by synergizing the multiobjective evolutionary optimization to simultaneously evolve the hyperparameters and architectures of DEC in an automatic manner. Firstly, a denoising autoencoder is integrated into the DEC to project the high-dimensional sparse scRNA-seq data into a low-dimensional space. After that, to guide the evolution, three objective functions are formulated to balance the model’s generality and clustering performance for robustness. Meanwhile, migration and mutation operators are proposed to optimize the objective functions to select the suitable hyperparameters and architectures of DEC in the multiobjective framework. Multiple comparison analyses are conducted on twenty synthetic data and eight real data from different representative single-cell sequencing platforms to validate the effectiveness. The experimental results reveal that the proposed algorithm outperforms other state-of-the-art clustering methods under different metrics. Meanwhile, marker genes identification, gene ontology enrichment and pathology analysis are conducted to reveal novel insights into the cell type identification and characterization mechanisms.
Biphasic regulation of transcriptional surge generated by the gene feedback loop in a two-component system
Authors: Liu Wen , Li Xiang , Qi Hong , Wu Yuning , Qu Jing , Yin Zhiyong , Gao Xuejuan , Han Aidong , Shuai Jianwei
Published: February 2021

Motivation

Transcriptional surges generated by two-component systems (TCSs) have been observed experimentally in various bacteria. Suppression of the transcriptional surge may reduce the activity, virulence and drug resistance of bacteria. In order to investigate the general mechanisms, we use a PhoP/PhoQ TCS as a model system to derive a comprehensive mathematical modeling that governs the surge. PhoP is a response regulator, which serves as a transcription factor under a phosphorylation-dependent modulation by PhoQ, a histidine kinase.

Results

Our model reveals two major signaling pathways to modulate the phosphorylated PhoP (P-PhoP) level, one of which promotes the generation of P-PhoP, while the other depresses the level of P-PhoP. The competition between the P-PhoP-promoting and the P-PhoP-depressing pathways determines the generation of the P-PhoP surge. Furthermore, besides PhoQ, PhoP is also a bifunctional modulator that contributes to the dynamic control of P-PhoP state, leading to a biphasic regulation of the surge by the gene feedback loop. In summary, the mechanisms derived from the PhoP/PhoQ system for the transcriptional surges provide a better understanding on such a sophisticated signal transduction system and aid to develop new antimicrobial strategies targeting TCSs.

Availability and implementation

https://github.com/jianweishuai/TCS.

Supplementary information

Supplementary data are available at Bioinformatics online.
Inference on the average treatment effect under minimization and other covariate-adaptive randomization methods
Authors: Ye Ting , Yi Yanyao , Shao Jun
Published: February 2021

Covariate-adaptive randomization schemes such as minimization and stratified permuted blocks are often applied in clinical trials to balance treatment assignments across prognostic factors. The existing theory for inference after covariate-adaptive randomization is mostly limited to situations where a correct model between the response and covariates can be specified or the randomization method has well-understood properties. Based on stratification with covariate levels utilized in randomization and a further adjustment for covariates not used in randomization, we propose several model-free estimators of the average treatment effect. We establish the asymptotic normality of the proposed estimators under all popular covariate-adaptive randomization schemes, including the minimization method, and we show that the asymptotic distributions are invariant with respect to covariate-adaptive randomization methods. Consistent variance estimators are constructed for asymptotic inference. Asymptotic relative efficiencies and finite-sample properties of estimators are also studied. We recommend using one of our proposed estimators for valid and model-free inference after covariate-adaptive randomization.
Pattern of recurrence in patients with a pathologically complete response after neoadjuvant chemoradiotherapy and surgery for oesophageal cancer
Authors: de Jongh M , Eyck B M , van der Werf L R , Toxopeus E L A , van Lanschot J J B , Lagarde S M , van der Gaast A , Nuyttens J , Wijnhoven B P L
Published: February 2021

Background

Neoadjuvant chemoradiotherapy (nCRT) and surgery is a widely used treatment for locally advanced resectable oesophageal cancer, with 20–50 per cent of patients having a pathological complete response (pCR). Disease, however, still recurs in 20–30 per cent of these patients. The aim of this study was to assess the pattern of recurrence in patients with a pCR after nCRT and surgery.

Methods

All patients with a pCR after nCRT and surgery included in the phase II and III CROSS (ChemoRadiotherapy for Oesophageal followed by Surgery Study) trials (April 2001 to December 2008) and after the CROSS trials (September 2009 to October 2017) were identified. The site of recurrence was compared with the applied radiation and surgical fields. Outcomes were median time to recurrence, and overall and progression-free survival.

Results

A total of 141 patients with a median follow-up of 100 (i.q.r. 64–134) months were included. Some 29 of 141 patients (20,6 per cent) developed recurrence. Of these, four had isolated locoregional recurrence, 15 had distant recurrence only, and ten had both locoregional and distant recurrence. Among the 14 patients with locoregional recurrences, five had recurrence within the radiation field, seven outside the radiation field, and two at the border. Median time to recurrence was 24 (10–62) months. The 5-year overall survival rate was 74 per cent and the recurrence-free survival rate was 70 per cent.

Conclusion

Despite good overall survival, recurrence still occurred in 21 per cent of patients. Most recurrences were distant, outside the radiation and surgical fields.
Postoperative outcome after reoperative isolated tricuspid valve surgery—is there a predictor for survival?
Authors: Pfannmueller Bettina , Budde Luca-Marie , Etz Christian D , Noack Thilo , Cuartas Mateo Marin , Misfeld Martin , Borger Michael A
Published: February 2021

OBJECTIVES

Reoperative tricuspid valve (TV) surgery is considered high risk even in the absence of additional concomitant cardiac procedures. The purpose of this study was to evaluate preoperative clinical parameters as predictors for survival after isolated reoperative TV surgery.

METHODS

From January 2005 to January 2019, 85 patients (mean age: 66.7 ± 10.3 years, 34 male) with severe isolated TV regurgitation and prior cardiac surgery were referred to our centre for elective or urgent TV repair/replacement; patients with endocarditis were excluded. We retrospectively analysed preoperative hepatorenal function [reflected by widely used clinical and laboratory parameters and the Model of End-stage-Liver Disease excluding International Normalized Ratio (MELD-XI) score] as a predictor for postoperative survival.

RESULTS

At hospital admission, the patients’ average preoperative New York Heart Association class was 2.9 ± 0.6, left ventricular ejection fraction 52.5 ± 10.6%, mean pulmonary artery pressure 24.7 ± 8.0 mmHg, creatinine 115.4 ± 66.6 μmol/l, bilirubin 20.0 ± 19.6 μmol/l and the mean MELD-XI score was 13.3 ± 4.0 μmol/l. The mean follow-up was 5.4 ± 4.2 years. Thirty-day mortality was 5%, 5-year survival was 60.6 ± 5.4% and 10-year survival was 42.9 ± 6.5%. The multivariable Cox regression analysis evaluated the MELD-XI score [hazard ratio (HR 1.144, confidence interval 95% 1.0–1.3, P = 0.005] and diabetes mellitus (HR 2.27, confidence interval 95% 1.0–5.0, P = 0.04) as significant predictors for excess mortality while age and mean pulmonary artery pressure did not reliably predict clinical outcome.

CONCLUSIONS

Hepatorenal dysfunction was one main factor accounting for limited postoperative survival in our patient cohort. The MELD-XI score is easy to calculate and seems to reliably predict the perioperative risk in patients with prior cardiac surgery and indication for TV surgery.
Vertical stability of different orthognathic treatments for correcting skeletal anterior open bite: a systematic review and meta-analysis
Authors: Wang Mengqiao , Zhang Bowen , Li Lan , Zhai Mingrui , Wang Zhengyan , Wei Fulan
Published: February 2021

Background

Several orthognathic procedures have been applied to correct skeletal anterior open bites (SAOB). Which method is most stable has been debated and no consensus has been reached and there is no conclusive evidence for clinicians to use.

Objective

To analyse whether maxillary, mandibular, or bimaxillary surgery provides a better stability.

Materials and methods

A systematic search was conducted up to December 2020 using PubMed, EMBASE, Medline, Scopus, Web of Science, Cochrane CENTRAL, and Google Scholar. We made direct comparisons among the controlled trials and also made indirect comparisons via subgroup analysis on the aspects of occlusional, skeletal, and dento-alveolar stability to assess the overall stability of each method.

Results

Finally 16 cohort studies were identified. At the occlusional level, pooled change in overbite was 0.21 mm in maxillary surgery, 0.37 mm in bimaxillary surgery, and −0.32 mm in mandibular surgery. At the skeletal level, pooled sella–nasion–Point A angle (SNA) was −0.12 degrees in bimaxillary surgery, −0.37 degrees in maxillary surgery and −0.20 degrees in mandibular surgery. The sella–nasion to palatal plane angle (SNPP) relapsed to a statistically significant degree in all samples received single maxillary surgery. Relapse of the sella–nasion–Point B angle (SNB) was 0.47 degrees in mandibular setback, −1.8 degrees in mandibular advancement, and −0.48 degrees in maxillary surgery. The Sella–Nasion to mandibular plane angle (SNMP) relapsed more in procedures involving bilateral sagittal split osteotomy than in other procedures. As for dento-alveolar changes, intrusion of molars and extrusion of incisors took place in most patients.

Conclusions

Bimaxillary surgery produced the most beneficial post-operative increase in overbite, maxillary surgery led to a lesser but still positive overbite change, and mandibular surgery correlated with some extent of relapse. Skeletally, bimaxillary surgery was more stable than maxillary surgery at both SNA and SNPP; SNB was more stable in mandibular setback than advancement; and SNMP was unstable in both mandibular and bimaxillary surgeries versus maxillary surgery with comparable surgical changes. Dento-alveolar compensation helped maintain a positive overbite.

Registration number

CRD42020198088.
Sleep arousal burden is associated with long-term all-cause and cardiovascular mortality in 8001 community-dwelling older men and women
Authors: Shahrbabaki Sobhan Salari , Linz Dominik , Hartmann Simon , Redline Susan , Baumert Mathias
Published: February 2021

Aims 

To quantify the arousal burden (AB) across large cohort studies and determine its association with long-term cardiovascular (CV) and overall mortality in men and women.

Methods and results 

We measured the AB on overnight polysomnograms of 2782 men in the Osteoporotic Fractures in Men Study (MrOS) Sleep study, 424 women in the Study of Osteoporotic Fractures (SOF) and 2221 men and 2574 women in the Sleep Heart Health Study (SHHS). During 11.2 ± 2.1 years of follow-up in MrOS, 665 men died, including 236 CV deaths. During 6.4 ± 1.6 years of follow-up in SOF, 105 women died, including 47 CV deaths. During 10.7 ± 3.1 years of follow-up in SHHS, 987 participants died, including 344 CV deaths. In women, multivariable Cox proportional hazard analysis adjusted for common confounders demonstrated that AB is associated with all-cause mortality [SOF: hazard ratio (HR) 1.58 (1.01–2.42), P = 0.038; SHHS-women: HR 1.21 (1.06–1.42), P = 0.012] and CV mortality [SOF: HR 2.17 (1.04–4.50), P = 0.037; SHHS-women: HR 1.60 (1.12–2.28), P = 0.009]. In men, the association between AB and all-cause mortality [MrOS: HR 1.11 (0.94–1.32), P = 0.261; SHHS-men: HR 1.31 (1.06–1.62), P = 0.011] and CV mortality [MrOS: HR 1.35 (1.02–1.79), P = 0.034; SHHS-men: HR 1.24 (0.86–1.79), P = 0.271] was less clear.

Conclusions

Nocturnal AB is associated with long-term CV and all-cause mortality in women and to a lesser extent in men.
Core–mantle topographic coupling: a parametric approach and implications for the formulation of a triaxial three-layered Earth rotation
Authors: Zhang Huifeng , Shen Wenbin
Published: February 2021

We propose a parametric approach to the topographic (TOP) coupling between the mantle and outer core for refinement of the latest triaxial three-layered Earth rotation theory. Based on three models of the core–mantle boundary (CMB) topography, we obtain the axial components of the TOP torque as −2.08 × 1019, −2.72 × 1018 and −1.97 × 1017 N m, respectively. Under the frame of the triaxial three-layered Earth rotation theory, we solve the corresponding periods of free core nutation as −(329.83 ± 28.12), −(457.54 ± ∼) and −(428.23 ± 1.09) mean solar days (d), respectively. The other three normal modes, namely, Chandler wobble, inner core wobble and free inner core nutation, are almost not affected by the TOP coupling of the CMB, their period values being 433.24, 2718.69 and 934.02 d, respectively. Calculations show that the TOP torque is highly sensitive to the adopted model of the topography, which is known to be robust. Taking into account the normal modes of the triaxial three-layered Earth rotation, the results of the CMB topography obtained by seismic tomography can be constrained in the future to a certain extent. In this study, considering the TOP coupling with the appropriate topography model, the estimates for the dynamic ellipticity ef of the fluid core lie between 0.0026340 and 0.0026430, values that are 3.56 % higher than the hydrostatic equilibrium value.
Endometrial Receptivity Analysis (ERA): data versus opinions
Authors: Ruiz-Alonso Maria , Valbuena Diana , Gomez Carlos , Cuzzi Juliana , Simon Carlos
Published: February 2021

This article summarises and contextualises the accumulated basic and clinical data on the ERA test and addresses specific comments and opinions presented by the opponent as part of an invited debate. Progress in medicine depends on new technologies and concepts that translate to practice to solve long-standing problems. In a key example, combining RNA sequencing data (transcriptomics) with artificial intelligence (AI) led to a clinical revolution in personalising disease diagnosis and fostered the concept of precision medicine. The reproductive field is no exception. Translation of endometrial transcriptomics to the clinic yielded an objective definition of the limited time period during which the maternal endometrium is receptive to an embryo, known as the window of implantation (WOI). The WOI is induced by the presence of exogenous and/or endogenous progesterone (P) after proper oestradiol (E2) priming. The window lasts 30–36 hours and, depending on the patient, occurs between LH + 6 and LH + 9 in natural cycles or between P + 4 and P + 7 in hormonal replacement therapy (HRT) cycles. In approximately 30% of IVF cycles in which embryo transfer is performed blindly, the WOI is displaced and embryo-endometrial synchrony is not achieved. Extending this application of endometrial transcriptomics, the endometrial receptivity analysis (ERA) test couples next-generation sequencing (NGS) to a computational predictor to identify transcriptomic signatures for each endometrial stage: proliferative (PRO), pre-receptive (PRE), receptive (R) and post-receptive (POST). In this way, personalised embryo transfer (pET) may be possible by synchronising embryo transfer with each patient’s WOI. Data are the only way to confront arguments sustained in opinions and/or misleading concepts; it is up to the reader to make their own conclusions regarding its clinical utility.
Plain convergence of adaptive algorithms without exploiting reliability and efficiency
Authors: Gantner Gregor , Praetorius Dirk
Published: February 2021

We consider $h$-adaptive algorithms in the context of the finite element method and the boundary element method. Under quite general assumptions on the building blocks SOLVE, ESTIMATE, MARK and REFINE of such algorithms we prove plain convergence in the sense that the adaptive algorithm drives the underlying a posteriori error estimator to zero. Unlike available results in the literature, our analysis avoids the use of any reliability and efficiency estimate but relies only on structural properties of the estimator, namely stability on nonrefined elements and reduction on refined elements. In particular, the new framework thus also covers problems involving nonlocal operators like the fractional Laplacian or boundary integral equations, where (discrete) efficiency is (currently) not available.
A Review of the Challenges and Complexities in the Diagnosis, Etiology, Epidemiology, and Pathogenesis of Pelvic Inflammatory Disease
Authors: Hillier Sharon L , Bernstein Kyle T , Aral Sevgi
Published: February 2021

Pelvic inflammatory disease (PID) is a syndrome that causes substantial morbidity, including chronic pelvic pain, to women globally. While limited data are available from low- and middle-income countries, national databases from the United States and Europe suggest that PID incidence may be decreasing but the rate of decrease may differ by the etiologic cause. Recent studies of women with PID have reported that fewer than half of women receiving a diagnosis of PID have gonococcal or chlamydial infection, while Mycoplasma genitalium, respiratory pathogens, and the constellation of bacteria associated with bacterial vaginosis may account for a substantial fraction of PID cases. The clinical diagnosis of PID is nonspecific, creating an urgent need to develop noninvasive tests to diagnose PID. Advances in serologic testing for Chlamydia trachomatis and Neisseria gonorrhoeae could advance epidemiologic studies, while the development of vaccines against these sexually transmitted pathogens could affect incident PID and associated morbidity.
The Association Between Antibody Response to Severe Acute Respiratory Syndrome Coronavirus 2 Infection and Post–COVID-19 Syndrome in Healthcare Workers
Authors: Pereira Christopher , Harris Benjamin H L , Di Giovannantonio Matteo , Rosadas Carolina , Short Charlotte-Eve , Quinlan Rachael , Sureda-Vives Macià , Fernandez Natalia , Day-Weber Isaac , Khan Maryam , Marchesin Federica , Katsanovskaja Ksenia , Parker Eleanor , Taylor Graham P , Tedder Richard S , McClure Myra O , Dani Melanie , Fertleman Michael
Published: February 2021

It is currently unknown how post-COVID-19 syndrome (PCS) may affect those infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This longitudinal study includes healthcare staff who tested positive for SARS-CoV-2 between March and April 2020, with follow-up of their antibody titers and symptoms. More than half (21 of 38) had PCS after 7–8 months. There was no statistically significant difference between initial reverse-transcription polymerase chain reaction titers or serial antibody levels between those who did and those who did not develop PCS. This study highlights the relative commonality of PCS in healthcare workers and this should be considered in vaccination scheduling and workforce planning to allow adequate frontline staffing numbers.
Demographics matter: the potentially disproportionate effect of COVID-19 on hospital ratings
Authors: Belasen Ariel R , Tracey Marlon R , Belasen Alan T
Published: February 2021

Objective

To identify how features of the community in which a hospital serves differentially relate to its patients' experiences based on the quality of that hospital.

Design

A Finite Mixture Model (FMM) is used to uncover a mix of two latent groups of hospitals that differ in quality. In the FMM, a multinomial logistic equation relates hospital-level factors to the odds of being in either group. A multiple linear regression relates the characteristics of communities served by hospitals to the patients' expected ratings of their experiences at hospitals in each group. Thus, this association potentially varies with hospital quality. The analysis was conducted via Stata.

Setting

Hospital ratings are measured by Hospital Compare using the Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) survey, a patient satisfaction survey required by the Centers for Medicare and Medicaid Services for hospitals in the USA.

Participants

2,816 Medicare-certified acute care hospitals across all US states.

Intervention

None.

Main Outcome Measure

Differences in the marginal impacts of key community demographics on patient experiences between the two groups of hospitals.

Results

We provide evidence that low-rated hospitals have much more variability in patient experience ratings than high-rated ones. Moreover, the experiences at low-rated hospitals are more sensitive to county demographic factors, which means exogenous shocks, like coronavirus disease-2019 (COVID-19), will likely affect these hospitals differently, as such shocks are known to disproportionately affect their communities.

Conclusions

Our results imply that low-rated hospitals with more variability in their HCAHPS responses are more likely to face adverse patient experiences due to COVID-19 than high-rated hospitals. Pandemics like COVID-19 create conditions that intensify the already high demands placed on hospitals and care providers and make it even more challenging to deliver quality care.
Fecal Microbiota Transplantation for the Treatment of Ulcerative Colitis: A Qualitative Assessment of Patient Perceptions and Experiences
Authors: Chauhan Usha , Popov Jelena , Farbod Yasamin , Kalantar Mona , Wolfe Melanie , Moayyedi Paul , Marshall John K , Halder Smita , Kaasalainen Sharon
Published: February 2021

Background

Fecal microbiota transplantation (FMT) is a promising experimental therapy for ulcerative colitis (UC), yet patient acceptance remains poorly understood.

Aims

The aim of this study was to explore perceptions and experiences of adult patients who received FMT for UC.

Methods

This study used a qualitative descriptive design with thematic content analysis. Patients who were approached for enrollment in a clinical trial (NCT02606032) were invited to participate in face-to-face semistructured interviews. Two groups were interviewed: those who chose to pursue FMT and those who declined FMT. Non-FMT patients were interviewed once; FMT patients were interviewed twice at pre- and post-treatment.

Results

Nine FMT patients (78% female, average age 46.7 years old) and eight non-FMT patients (50% female, average age 39.5 years old) were enrolled. Pretreatment themes included FMT as a natural therapy, external barriers to pursuing FMT, concerns with FMT and factors influencing the decision to pursue FMT. While both groups generally perceived FMT as a natural therapy, pre-FMT patients showed greater acceptance of alternative medicine. Both groups demonstrated poor understanding and similar initial concerns with product cleanliness. Pre-FMT patients were motivated to pursue FMT by feelings of last resort. Post-FMT themes included therapeutic impact of FMT and psychosocial impact of FMT. Post-FMT patients reported overall satisfaction and a unanimous preference for FMT over conventional medications.

Conclusion

This is the first study to assess adult patient perceptions and real-life experiences with FMT for the treatment of UC. By improving patient education, we may achieve greater acceptance of FMT.
Analysis of misaligned journal bearing lubrication performance considering the effect of lubricant couple stress and shear thinning
Authors: Zhu Junchao , Qian Haiyu , Wen Huabing , Zheng Liangyan , Zhu Hanhua
Published: February 2021

This paper investigates journal bearings, and builds a lubrication model taking into account misalignment, the lubricant couple stress effect and shear thinning. In order to explore the sensitivity of couple stress fluid lubrication performance to oil film thickness, we introduce the critical oil film thickness coefficient. The results show that the sensitivity increases with the increase of the couple stress coefficient, and it is highest in the area of minimum oil film thickness. Compared with a parallel journal, increases in the misalignment angle strengthen the effect of couple stress. Shear thinning also plays an important role in bearing lubrication performance. For a low oil inlet temperature, the effect of shear thinning increases with the increase of the couple stress parameter. For a high oil inlet temperature, the influence is negligible. An increase in the misalignment angle will not further enhance the effect of shear thinning.
Vaccination coverage in children resident in a rural community in Nigeria: socio-ecological and contextual determinants
Authors: Iribhogbe Osede Ignis , Tomini Sonila
Published: February 2021

Objectives

The national vaccination coverage rate and the coverage rate in rural communities in Nigeria are below the global vaccine action target of 80%; hence, evaluation of factors that determine vaccination status and determine the proportion of children aged 12–59 months who are fully immunised in the rural community should be conducted.

Methods

A cross-sectional study was conducted using an interview-structured questionnaire that was pilot tested before being administered. In the study, a two-stage sampling technique was used and the sample size was determined using the EPI-Info, version 7, software.

Key Findings

Of the 608 caregiver–child pairs that was assessed, the majority (525, 86.35%) were mothers. Assessment of immunisation status showed that the majority of the children (429, 70.56%) were completely vaccinated while 179 (29.44%) were incompletely vaccinated. Educational status (χ 2 = 59.85, df = 4, P < 0.001), the level of knowledge about vaccination (χ 2 = 77.62, df = 2, P < 0.001), family setting (χ 2 = 27.70, df = 3, P < 0.001), maternal ANC visits (χ 2 = 85.37, df = 2, P < 0.001), type of birth (χ 2 = 7.27, df = 2, P = 0.03) and child’s breastfeeding status (χ 2 = 80.75, df = 2, P < 0.001) were all significantly associated with the vaccination status of the child.

Conclusion

The study has shown that immunisation coverage in the rural community surveyed is still below the expected target; thus, public health intervention should still focus on individual, community, socio-cultural and healthcare-related factors as this will improve the immunisation status of children in rural communities.
Endonasal endoscopic management of different cases of dentigerous cysts and ectopic teeth
Authors: Alhashim Fadak Yousef , Almarhoon Fatimah Salman , Alhashim Hassan Yousef , Moumen Ali
Published: February 2021

Dentigerous cyst is a type of developmental odontogenic cysts that arises from the crown impacted, embedded or unerupted teeth that standardly managed by Caldwell-luc procedure, which is found to be associated with morbidities and complications. Endonasal endoscopic removal is a minimally invasive approach aiming to prevent morbidities and complications. The aim of this article is to study the advantages of the endonasal endoscopic approach in managing different cases of dentigerous cyst and ectopic teeth. In this article, we reported three different cases (two pediatric and one adult), one presenting with unilateral dentigerous cyst with traumatic ectopic teeth in the maxillary sinus, and one presenting with bilateral dentigerous cysts and ectopic teeth in the maxillary sinuses, the third case of unilateral ectopic intranasal canine tooth. All managed by endonasal endoscopic approach, with no complications and complete recovery. The endonasal endoscopic approach is a minimally invasive surgical approach. With the use of different angled endoscopes and instruments, this approach is preserving physiological function while minimizing morbidity and preventing complications.
SARS-CoV-2 Variant of Concern 202 012/01 (B.1.1.7) in a traveller from the UK to China
Authors: Yao Mingxiao , Jiang Fachun , Zhang Yuwei , Li Yan , Pang Bo , Liang Hao , Kou Zengqiang , Jiang Xiaolin , Wen Hongling , Xu Yifei
Published: February 2021

We report the complete genome of SARS-CoV-2 VOC 202012/01 in a traveller from the UK to China, representing the first such case in North China. This study highlights that intensive genomic sequencing enables early identification and rapid characterization of the SARS-CoV-2 importing to China.
Galaxy and mass assembly (GAMA): the inferred mass–metallicity relation from z = 0 to 3.5 via forensic SED fitting
Authors: Bellstedt Sabine , Robotham Aaron S G , Driver Simon P , Thorne Jessica E , Davies Luke J M , Holwerda Benne W , Hopkins Andrew M , Lara-Lopez Maritza A , López-Sánchez Ángel R , Phillipps Steven
Published: February 2021

We analyse the metallicity histories of ∼4500 galaxies from the GAMA survey at z < 0.06 modelled by the SED-fitting code ProSpect using an evolving metallicity implementation. These metallicity histories, in combination with the associated star formation histories, allow us to analyse the inferred gas-phase mass–metallicity relation. Furthermore, we extract the mass–metallicity relation at a sequence of epochs in cosmic history, to track the evolving mass–metallicity relation with time. Through comparison with observations of gas-phase metallicity over a large range of redshifts, we show that, remarkably, our forensic SED analysis has produced an evolving mass–metallicity relationship that is consistent with observations at all epochs. We additionally analyse the three-dimensional mass–metallicity–SFR space, showing that galaxies occupy a clearly defined plane. This plane is shown to be subtly evolving, displaying an increased tilt with time caused by general enrichment, and also the slowing down of star formation with cosmic time. This evolution is most apparent at lookback times greater than 7 Gyr. The trends in metallicity recovered in this work highlight that the evolving metallicity implementation used within the SED-fitting code ProSpect produces reasonable metallicity results over the history of a galaxy. This is expected to provide a significant improvement to the accuracy of the SED-fitting outputs.
Horizontal spreading of planetary debris accreted by white dwarfs
Authors: Cunningham Tim , Tremblay Pier-Emmanuel , Bauer Evan B , Toloza Odette , Cukanovaite Elena , Koester Detlev , Farihi Jay , Freytag Bernd , Gänsicke Boris T , Ludwig Hans-Günter , Veras Dimitri
Published: February 2021

White dwarfs with metal-polluted atmospheres have been studied widely in the context of the accretion of rocky debris from evolved planetary systems. One open question is the geometry of accretion and how material arrives and mixes in the white dwarf surface layers. Using the three-dimensional (3D) radiation hydrodynamics code co5bold, we present the first transport coefficients in degenerate star atmospheres that describe the advection–diffusion of a passive scalar across the surface plane. We couple newly derived horizontal diffusion coefficients with previously published vertical diffusion coefficients to provide theoretical constraints on surface spreading of metals in white dwarfs. Our grid of 3D simulations probes the vast majority of the parameter space of convective white dwarfs, with pure-hydrogen atmospheres in the effective temperature range of 6000–18 000 K and pure-helium atmospheres in the range of 12 000–34 000 K. Our results suggest that warm hydrogen-rich atmospheres (DA; ${\gtrsim} 13\, 000$ K) and helium-rich atmospheres (DB and DBA; ${\gtrsim} 30\, 000$ K) are unable to efficiently spread the accreted metals across their surface, regardless of the time dependence of accretion. This result may be at odds with the current non-detection of surface abundance variations in white dwarfs with debris discs. For cooler hydrogen- and helium-rich atmospheres, we predict a largely homogeneous distribution of metals across the surface within a vertical diffusion time-scale. This is typically less than 0.1 per cent of disc lifetime estimates, a quantity that is revisited in this paper using the overshoot results. These results have relevance for studies of the bulk composition of evolved planetary systems and models of accretion disc physics.