bluuebunny/crossref_metadata_2025 huggingface dataset:
Impacts of the Westerlies on Planetary Boundary Layer Growth Over a Valley on the North Side of the Central Himalayas
Authors: Lai Yue , Chen Xuelong , Ma Yaoming , Chen Deliang , Zhaxi Suolang
Published: December 2020

This study focused on planetary boundary layer (PBL) growth in winter under the influence of the westerlies over the Rongbuk Valley on the north side of the central Himalayas. Two sunny November days in 2014 with different synoptic conditions in terms of large‐scale wind direction and speed were selected to investigate the ways in which large‐scale synoptic forcing affected the vertical structure of the PBL, atmospheric stability, surface wind field, and land surface energy fluxes. This was done by using radiosonde and in‐situ measurements, the European Centre for Medium‐Range Weather Forecasts ERA5 reanalysis data set, and a one‐dimensional model. The results revealed that the valley winds and PBL growth were strongly influenced by the variations of the westerlies, which prevail in this region during the winter. When the synoptic wind direction at the height of the mountain ridges was parallel to the axis of the valley and strong, the downward transmission of the westerlies to the valley floor (DTWTV) was strong, causing high near‐surface wind speeds and sensible heat flux values. These conditions, together with a deep residual layer, unstable atmosphere, and thermally driven local wind, produced an extremely deep PBL (9 km above sea level) in the early afternoon of November 23. When the synoptic wind direction at the ridge height intersected the axis of the valley and was weak, the DTWTV was weak, and the PBL became relatively low on November 28. These results demonstrate that the interaction between the topography and synoptic circulation plays a critical role in PBL growth.
Author Correction: Humanizing the mdx mouse model of DMD: the long and the short of it
Authors: Yucel Nora , Chang Alex C. , Day John W. , Rosenthal Nadia , Blau Helen M.
Published: December 2020

A correction to this paper has been published: https://doi.org/10.1038/s41536-020-00112-0.
Simultaneous measurement of neurite and neural body mass accumulationviaquantitative phase imaging
Authors: Pradeep Soorya , Tasnim Tasmia , Zhang Huanan , Zangle Thomas A.
Published: December 2020

Quantitative phase imaging (QPI) used to quantify the mass of soma (cell bodies) and neurites as well as the rates of biomass production due to neurite maturation and formation during neural differentiation.
Multimodal chemical imaging of a single brain tissue section using ToF-SIMS, MALDI-ToF and immuno/histochemical staining
Authors: Kaya Ibrahim , Jennische Eva , Lange Stefan , Malmberg Per
Published: December 2020

ToF-SIMS and/or MALDI-ToF imaging mass spectrometry of a single brain tissue section followed by classical- or immuno- histochemical staining.
An all-inorganic quasi-homogenous polyoxometalate/[Mo3S13]2− system for efficient and stable photocatalytic H2 evolution
Authors: Li Wenbo , Min Shixiong , Wang Fang , Zhang Zhengguo , Gao Dawei
Published: December 2020

An all-inorganic quasi-homogenous photocatalytic system employing a polyoxometalate as the photosensitizer and [Mo3S13]2− as the catalyst exhibits high activity and stability for H2 evolution.
High efficiency and stable photoluminescence of CH3NH3PbBr3@CsPbBr3 perovskite quantum dots
Authors: Wang Yajing , Li Ahui , Hu Yizhen , Bao Yanping , Zhang Yongfan , Hu Xiaolin , Zhuang Naifeng
Published: December 2020

CH3NH3PbBr3@CsPbBr3 QDs were prepared by epitaxially growing inorganic perovskite CsPbBr3 on surface of cubic CH3NH3PbBr3. Photoluminescence of CH3NH3PbBr3@CsPbBr3 QDs is not only strong but also stable for months, and the quantum yield is high.
DMSO/SOCl2-mediated C(sp2)–H amination: switchable synthesis of 3-unsubstituted indole and 3-methylthioindole derivatives
Authors: Zhang Jingran , Li Xiaoxian , Li Xuemin , Shi Haofeng , Sun Fengxia , Du Yunfei
Published: December 2020

The reaction of 2-alkenylanilines with SOCl2 in DMSO was found to selectively afford 3-unsubstituted indoles and 3-methylthioindoles. This switchable approach was found to be temperature-dependent.
Ab initioGibbs ensemble Monte Carlo simulations of the liquid–vapor equilibrium and the critical point of sodium
Authors: Li Zhi , Winisdoerffer Christophe , Soubiran François , Caracas Razvan
Published: December 2020

We extend the application of theab initioGibbs ensemble method to the metallic system by including the contribution of excited electronic states.
Ab initio molecular dynamics of hydrogen on tungsten surfaces
Authors: Rodríguez-Fernández Alberto , Bonnet Laurent , Larrégaray Pascal , Muiño Ricardo Díez
Published: December 2020

The dissociation process of hydrogen molecules on W(110) was studied using density functional theory and classical molecular dynamics.
COx-free hydrogen production via ammonia decomposition over mesoporous Co/Al2O3 catalysts with highly dispersed Co species synthesized by a facile method
Authors: Gu Yingqiu , Xu Di , Huang Yun , Long Zhouyang , Chen Guojian
Published: December 2020

Highly dispersed cobalt particles are well embedded into mesoporous alumina. The aggregation of cobalt species is prevented by the alumina matrix due to strong interaction, thus ensuring a superior catalytic activity for ammonia decomposition.
Cleavage of C–O and C–H bonds in ethers by a genuine SiO bond
Authors: Kobayashi Ryo , Ishida Shintaro , Iwamoto Takeaki
Published: December 2020

A dialkylsilanone with a genuine SiO bond undergoes the cleavage of an ethereal C–O bond which is initiated by the coordination of the ethereal O atom to the electrophilic Si atom in the SiO bond.
Correction: Revisiting thin silicon for photovoltaics: a technoeconomic perspective
Authors: Liu Zhe , Sofia Sarah E. , Laine Hannu S. , Woodhouse Michael , Wieghold Sarah , Peters Ian Marius , Buonassisi Tonio
Published: December 2020

Correction for ‘Revisiting thin silicon for photovoltaics: a technoeconomic perspective’ by Zhe Liu et al., Energy Environ. Sci., 2020, 13, 12–23, DOI: 10.1039/C9EE02452B.
Electronic relaxation of aqueous aminoazobenzenes studied by time-resolved photoelectron spectroscopy and surface hopping TDDFT dynamics calculations
Authors: Titov Evgenii , Hummert Johan , Ikonnikov Evgenii , Mitrić Roland , Kornilov Oleg
Published: December 2020

We use time-resolved photoelectron spectroscopy in solution to follow relaxation of two prototypical aqueous chromophores, Methyl Orange and Metanil Yellow.
Correction: Optical properties and carrier dynamics in Co-doped ZnO nanorods
Authors: Sivan Aswathi K. , Galán-González Alejandro , Di Mario Lorenzo , Tappy Nicolas , Hernández-Ferrer Javier , Catone Daniele , Turchini Stefano , Benito Ana M. , Maser Wolfgang K. , Steinvall Simon Escobar , Fontcuberta i Morral Anna , Gallant Andrew , Zeze Dagou A. , Atkinson Del , Martelli Faustino
Published: December 2020

Correction for ‘Optical properties and carrier dynamics in Co-doped ZnO nanorods’ by Aswathi K. Sivan et al., Nanoscale Adv., 2021, DOI: 10.1039/d0na00693a.
KCNQ1OT1 regulates the retinoblastoma cell proliferation, migration and SIRT1/JNK signaling pathway by targeting miR-124/SP1 axis
Authors: Zhang Haitao , Yang Xin , Xu Yingying , Li Haijun
Published: December 2020

Objective: Long non-coding RNA (lncRNA) KCNQ1OT1 was reported to be tightly associated with tumorigenesis and progression of multiple cancers. However, the expression and biological functions of KCNQ1OT1 in retinoblastoma (RB) are still unknown. We aim to elucidate the potential function and underlying mechanism of KCNQ1OT1 in regulating the progression of RB. Methods: The levels of KCNQ1OT1 were assayed by real-time fluorescence quantitative polymerase chain reaction (RT-qPCR) analysis. The cell proliferation of RB cells (Y79 and WERI-Rb-1) were evaluated through Cell Counting Kit 8 (CCK-8) assay. Meanwhile, Y79 and WERI-Rb-1 cell apoptosis and cell cycle were assessed by Flow Cytometry analysis. Dual luciferase reporter assay were performed to illustrate the interaction between KCNQ1OT1, miR-124, and SP1. Results: We found that KCNQ1OT1 was up-regulated and miR-124 was down-regulated in RB tissues and cells. Moreover, knockdown of KCNQ1OT1 reduced the proliferation, migration, and cell cycle, as well as promoted cell apoptosis of Y79 and WERI-Rb-1 cells. Western blot analysis consistently proved cell cycle and apoptosis related protein expression levels. More importantly, KCNQ1OT1 was a sponge of microRNA (miR)-124. MiR-124 inhibition strongly reversed the effect on cell proliferation, cycle arrest, and apoptosis by KCNQ1OT1 knockdown mediation. In addition, KCNQ1OT1 regulated expression of SP1, a direct target of miR-124 in RB. On the other hand, miR-124 inhibitor abrogated the active effect of KCNQ1OT1 silencing on silent information regulator 1 (SIRT1)/c-Jun N-terminal kinase (JNK) signaling pathway. The function of KCNQ1OT1 was verified in vivo. Conclusions: These findings implied that KCNQ1OT1 silencing inhibited RB progression and activated SIRT1/JNK signaling pathway partially by modulating the miR-124/SP1 axis.
Bioinformatics analysis identifies COL1A1, THBS2 and SPP1 as potential predictors of patient prognosis and immunotherapy response in gastric cancer
Authors: Wang Yali , Zheng Kun , Chen Xiuqiong , Chen Rui , Zou Yanmei
Published: December 2020

Background: The present study aimed to use bioinformatics tools to explore pivotal genes associated with the occurrence of gastric cancer (GC) and assess their prognostic significance, and link with clinicopathological parameters. We also investigated the predictive role of COL1A1, THBS2, and SPP1 in immunotherapy.

Materials and methods: We identified differential genes (DEGs) that were up- and down-regulated in the three datasets (GSE26942, GSE13911, and GSE118916) and created protein–protein interaction (PPI) networks from the overlapping DEGs. We then investigated the potential functions of the hub genes in cancer prognosis using PPI networks, and explored the influence of such genes in the immune environment.

Results: Overall, 268 overlapping DEGs were identified, of which 230 were up-regulated and 38 were down-regulated. CytoHubba selected the top ten hub genes, which included SPP1, TIMP1, SERPINE1, MMP3, COL1A1, BGN, THBS2, CDH2, CXCL8, and THY1. With the exception of SPP1, survival analysis using the Kaplan–Meier database showed that the levels of expression of these genes were associated with overall survival. Genes in the most dominant module explored by MCODE, COL1A1, THBS2, and SPP1, were primarily enriched for two KEGG pathways. Further analysis showed that all three genes could influence clinicopathological parameters and immune microenvironment, and there was a significant correlation between COL1A1, THBS2, SPP1, and PD-L1 expression, thus indicating a potential predictive role for GC response to immunotherapy.

Conclusion: ECM–receptor interactions and focal adhesion pathways are of great significance in the progression of GC. COL1A1, THBS2, and SPP1 may help predict immunotherapy response in GC patients.
Development of a prognostic model based on an immunogenomic landscape analysis of medulloblastoma
Authors: Guo Yuduo , Li Shenglun , Huang Peng , Zhang Hongwei , Yu Chunjiang
Published: December 2020

Medulloblastoma (MB) is one of the most common central nervous system tumors in children. At present, the vital role of immune abnormalities has been proved in tumorigenesis and progression. However, the immune mechanism in MB is still poorly understood. In the present study, 51 differentially expressed immune-related genes (DE-IRGs) and 226 survival associated immune-related genes (Sur-IRGs) were screened by an integrated analysis of multi-array. Moreover, the potential pathways were enriched by functional analysis, such as ‘cytokine–cytokine receptor interaction’, ‘Ras signaling pathway’, ‘PI3K-Akt signaling pathway’ and ‘pathways in cancer’. Furthermore, 10 core IRGs were identified from DE-IRGs and Sur-IRGs. And the potential regulatory mechanisms of core IRGs were also explored. Additionally, a new prognostic model, including 7 genes (HDGF, CSK, PNOC, S100A13, RORB, FPR1, and ICAM2) based on IRGs, was established by multivariable COX analysis. In summary, our study revealed the underlying immune mechanism of MB. Moreover, we developed a prognostic model associated with clinical characteristics and could reflect the infiltration of immune cells.
A paradox: Fe2+-containing agents decreased ROS and apoptosis induced by CoNPs in vascular endothelial cells by inhibiting HIF-1α
Authors: Zhu Wenfeng , Liu Yake , Wang Wei , Zhou Zihua , Gu Jin-hua , Zhang Zexu , Sun Huanjian , Liu Fan
Published: December 2020

Cobalt nanoparticles (CoNPs) released from hip joint implants are known to have a toxic effect on several organs probably through increasing reactive oxygen species (ROS). Ferrous ion (Fe2+) is well-known to enhance oxidative stress by catalysing the production of ROS. However, in our pilot study, we found that Fe2+ conversely inhibited the ROS production induced by CoNPs. To elucidate the underlying mechanism, the present study treated vascular endothelial HUVEC and HMEC-1 cells with CoNPs alone or in combination with ferrous lactate [Fe(CH3CHOHCOO)2], ferrous succinate [Fe(CH2COO)2], and ferrous chloride (FeCl2). CoNP toxicity was evaluated by measuring cell viability, rate of apoptosis and lactose dehydrogenase (LDH) release, and intracellular ROS levels. Treatment with CoNPs decreased cell viability, LDH release, and ROS production and increased apoptosis. CoNPs increased hypoxia-inducible factor-1α (HIF-1α) protein level and mRNA levels of vascular endothelial growth factor (VEGF) and glucose transporter 1 (GLUT1) downstream of HIF-1α signalling. Silencing HIF-1α attenuated CoNP toxicity, as seen by recovery of cell viability, LDH release, and ROS levels and reduced apoptosis. CoNPs caused a pronounced reduction of Fe2+ in cells, but supplementation with Fe(CH3CHOHCOO)2, Fe(CH2COO)2, and FeCl2 restored Fe2+ levels and inhibited HIF-1α activation. Moreover, all three Fe2+-containing agents conferred protection from CoNPs; Fe(CH3CHOHCOO)2 and Fe(CH2COO)2 more effectively than FeCl2. In summary, the present study revealed that CoNPs exert their toxicity on human vascular endothelial cells by depleting intracellular Fe2+ level, which causes activation of HIF-1α signalling. Supplements of Fe2+, especially in the form of Fe(CH3CHOHCOO)2 and Fe(CH2COO)2, mitigated CoNP toxicity.
A panel of two miRNAs correlated to systolic blood pressure is a good diagnostic indicator for stroke
Authors: Qi Yujun , Yuan Mingfeng , Yi Qiong , Wang Yan , Xu Lei , Xu Changsong , Lu Min
Published: December 2020

Background: We aimed to develop a diagnostic indicator of stroke based on serum miRNAs correlated to systolic blood pressure.

Methods: Using miRNA expression profiles in GSE117604 from the Gene Expression Omnibus (GEO), we utilized the WGCNA to identify hub miRNAs correlated to systolic blood pressure (SBP). Differential analysis was applied to highlight hub differentially expressed miRNAs (DE-miRNAs), whereby we built a miRNA-based diagnostic indicator for stroke using bootstrap ranking Least Absolute Shrinkage and Selection Operator (LASSO) regression with 10-fold cross-validation. The classification value of the indicator was validated with receiver operating characteristic (ROC) analysis in both the training set and test set, as well as quantitative real-time PCR (qRT-PCR) for the feature miRNAs. Further, target genes of hub miRNAs and hub DE-miRNAs were retrieved for functional enrichment.

Results: A total of 447 hub miRNAs in the blue modules were significantly correlated with systolic blood pressure (r = 0.32, false discovery rate = 10−6). Target genes predicted with the hub miRNAs were mostly implicated in the Kyoto Encyclopedia of Genes and Genomes (KEGG) terms including mitogen-activated protein kinase (MAPK) pathway, senescence, and TGF-β signaling pathway. The diagnostic indicator with miR-4420 and miR-6793-5p showed remarkable performance in the training set (area under curve [AUC]= 0.953), as well as in the test set (AUC = 0.894). Results of qRT-PCR validated the diagnostic value of the two miRNAs embedded in the proposed indicator.

Conclusions: We developed a panel of two miRNAs, which is a good diagnostic indicator for stroke. These results require further investigation.
Elevated CDK5R1 predicts worse prognosis in hepatocellular carcinoma based on TCGA data
Authors: Zeng Zhili , Cao Zebiao , Zhang Enxin , Huang Haifu , Tang Ying
Published: December 2020

Background: Hepatocellular carcinoma (HCC) is a malignant tumor with rapid progression, high recurrence rate and poor prognosis. The objective of our investigation was to explore the prognostic value of CDK5R1 in HCC.

Methods: The raw data of HCC raw data were downloaded from The Cancer Genome Atlas (TCGA) database. The Wilcoxon signed-rank test, Kruskal–Wallis test and logistic regression were applied to investigate the relevance between the CDK5R1 expression and clinicopathologic characteristics in HCC. Kaplan–Meier and Cox regression analysis were employed to examine the association between clinicopathologic features and survival. Gene set enrichment analysis (GSEA) was applied to annotate the biological function of CDK5R1.

Results: CDK5R1 was highly expressed in HCC tissues. The high expression of CDK5R1 in HCC tissues was significantly associated with tumor status (P=0.00), new tumor event (P=0.00), clinical stage (P=0.00) and topography (P=0.00). Elevated CDK5R1 had significant correlation with worse overall survival (OS; P=7.414e−04), disease-specific survival (DSS; P=5.642e−04), disease-free interval (DFI; P=1.785e−05) and progression-free interval (PFI; P=2.512e−06). Besides, univariate and multivariate Cox regression analysis uncovered that increased CDK5R1 can independently predict adverse OS (P=0.037, hazard ratio [HR]= 1.7 (95% CI [1.0–2.7])), DFI (P=0.007, hazard ratio [HR]= 3.0 (95% CI [1.4–6.7])), PFI (P=0.007, hazard ratio [HR]= 2.8 (95% CI [1.3–5.9])). GSEA disclosed that notch signaling pathway and non-small cell lung cancer were prominently enriched in CDK5R1 high expression phenotype.

Conclusions: Increased CDK5R1 may act as a promising independent prognostic factor of poor survival in HCC.
The Hearpiece database of individual transfer functions of an in-the-ear earpiece for hearing device research
Authors: Denk Florian , Kollmeier Birger
Published: December 2020

We present a database of acoustic transfer functions of the Hearpiece, a commercially available multi-microphone multi-driver in-the-ear earpiece for hearing device research. The database includes HRTFs for 87 incidence directions as well as responses of the drivers, all measured at the four microphones of the Hearpiece as well as the eardrum in the occluded and open ear. The transfer functions were measured in both ears of 25 human participants and a KEMAR with anthropometric pinnae for five insertions of the device. We describe the measurements of the database and analyse derived acoustic parameters of the device. All regarded transfer functions are subject to differences between participants and insertions. Also, the KEMAR measurements are close to the median of human data in the present results for all assessed transfer functions. The database is a rich basis for development, evaluation and robustness analysis of multiple hearing device algorithms and applications. It is openly available at https://doi.org/10.5281/zenodo.3733190.
Reassessment of amber-bearing deposits of Provence, southeastern France
Authors: Saint Martin Jean-Paul , Dutour Yves , Ebbo Luc , Frau Camille , Mazière Bruno , Néraudeau Didier , Saint Martin Simona , Tortosa Thierry , Turini Eric , Valentin Xavier
Published: December 2020

The presence of “geological” amber (or “succin” in old French monographs) has been reported for several centuries in the Mesozoic deposits of Provence, southeastern France. Diverse amber-bearing sites were inventoried by the authors but their location and stratigraphical context remain unclear for most of them. In the past decades, various data concerning chemistry, palaeontological content and comparison with archaeological discoveries improved our knowledge of the ambers of Provence, but only those of Cretaceous age. The present paper aims at providing a comprehensive description of all the presently known amber-bearing deposits of Provence, including the description of new sites. We highlight the great potential of Provence ambers and allow to consider a wider time range, from the Early Cretaceous to the Miocene.
Fire-induced changes in soil and vegetation in the forest-tundra of Western Siberia
Authors: Sizov Oleg , Brodt Leya , Soromotin Andrey , Prikhodko Nikolay , Heim Ramona
Published: December 2020

Wildfires are one of the main factors for landscape change in tundra ecosystems. In the absence of external mechanical impacts, tundra plant communities are relatively stable, even in the face of climatic changes. In our study, lichen cover was degraded on burnt tundra sites, which increased the permafrost thaw depth from 100 to 190 cm. In old fire scars (burnt 1980 – 1990) of the forest-tundra, vegetation cover was dominated by trees and shrubs. The soil temperature on burnt forest-tundra sites was higher in comparison to conditions of the unburnt control sites and permafrost was was not found at a depth of 2-2,3m. Dynamics of the Normalized Difference Vegetation index (NDVI) from 1986-2020 reveal that immediately after fires, vegetation recovered and biomass increased due to the development of Betula nana shrubs. In old fire scars of the forest-tundra (burnt 1980-1990), a significant increase in NDVI values was evident, in contrast to the unburnt tundra vegetation where this trend was less pronounced. We conclude that "greening" in the north of Western Siberia may occur due to fire-induced transformation processes. The role of wildfires in the advance of the treeline to the north, driven by climate change and active economic development of the Arctic, will gradually increase in future.
La lutte à travers le cafard à l’adolescence
Authors: Wawrzyniak Michel
Published: December 2020

Nous explorons une forme de lutte psychique à l’adolescence, celle que Winnicott dénomme lutte à travers le cafard, traduite aussi par lutte à travers le marasme. Les différentes luttes psychiques de l’adolescence interrogent la psychopathologie en ce qu’elles constituent des figures cliniques d’une psychopathologie normale à cet âge. Elles convoquent aussi, dans notre rencontre avec les adolescents, une interrogation sur les ressorts de l’expression et des transferts.
Place du Cesa, Centre d’évaluation et de soins pour adolescents, dans le parcours de soin des adolescents déprimés en Seine-et-Marne
Authors: Lacour Gonay Catherine
Published: December 2020

La spécificité de la prise en charge dans le parcours de soin des adolescents déprimés au Cesa, tient à la prise en compte du symptôme scolaire pour décliner une prise en charge individuelle, ambulatoire, institutionnelle et séquentielle autour d’un projet « soin-étude » individualisé avec le jeune et ses parents.
Retrospective Evaluation of Patients Treated for Ectopic Pregnancy: Experience of a Tertiary Center
Authors: Kömürcü Karuserci Özge , Sucu Seyhun
Published: December 2020

Objective In recent years, there has been an increase in the incidence of ectopic pregnancies; therefore, it is important for tertiary centers to report their approaches and outcomes to expand and improve treatment modalities. The aim of the present study was to evaluate the general characteristics, treatment and outcomes of cases diagnosed with ectopic pregnancy.

Methods In total, 432 patients treated for ectopic pregnancy between February 2016 and June 2019 were retrospectively evaluated.

Results Overall, 370 patients had tubal pregnancy, 32 had cesarean scar pregnancy, 18 had pregnancy of unknown location, 6 had cervical pregnancy, and 6 had interstitial pregnancy. The most important risk factors were advanced age (> 35 years; prevalence: 31.2%) and smoking (prevalence: 27.1%). Thirty patients who did not have any symptoms of rupture and whose human chorionic gonadotropin (β-hCG) levels were ≤ 200 mIU/ml were followed-up with expectant management, while 316 patients whose β-hCG levels were between 1,500 mIU/ml and 5,000 mIU/ml did not have an intrauterine gestational sac on the transvaginal or abdominal ultrasound, did not demonstrate findings of rupture, and were treated with a systemic multi-dose methotrexate treatment protocol. In total, 24 patients who did not respond to the medical treatment, 20 patients whose β-hCG levels were > 5,000 mIU/ml, 16 patients who had shown symptoms of rupture at the initial presentation, and 6 patients diagnosed with interstitial pregnancy underwent surgery. Patients with cervical and scar pregnancies underwent ultrasound-guided curettage, and no additional treatment was needed.

Conclusion The fertility status of the patients, the clinical and laboratory findings, and the levels of β-hCG are the factors that must be considered in planning the appropriate treatment.
Advantages and Disadvantages of Medical Abortion, According to Brazilian Residents in Obstetrics and Gynaecology
Authors: Bento Silvana Ferreira , Pádua Karla Simônia de , Pacagnella Rodolfo de Carvalho , Fernandes Karayna Gil , Osis Maria José Duarte , Duarte Graciana Alves , Faúndes Anibal
Published: December 2020

Objective To find out which was the opinion of residents in obstetrics and gynecology about the advantages and disadvantages of medical abortion as compared with surgical procedures.

Method Cross-sectional multicenter study among residents in obstetrics and gynecology from 21 maternity hospitals located in 4 different geographical regions of Brazil, using a self-responded questionnaire with 31 questions related to their opinion and experience on providing abortion services.

Results Most residents agreed that “being less invasive” (94.7%), “does not require anesthesia” (89.7%), “can be accompanied during the process” (89.1%), “prevents physical trauma” (84.4%) were the main advantages of medical abortion.

Conclusion Residents perceived both clinical and personal issues as advantages of medical abortion.
Atmospheric conditions and yaw misalignment significantly impact wind turbine power production
Authors: Larter Raima
Published: December 2020

Detailed model, validated by field data, reveals mechanism by which yaw misalignment and atmospheric conditions influence wind power production.
Property manipulation through pulsed laser annealing in high dose Mg-implanted GaN
Authors: Shi Ya-Ting , Ren Fang-Fang , Hao Jinggang , Wang Zhengpeng , Ye Jiandong , Xu Wei-Zong , Zhou Dong , Zhang Rong , Zheng Youdou , Lu Hai
Published: December 2020

The generation of p-type GaN through ion implantation is an attractive proposition in the massive production of GaN-based bipolar devices, whereas the removal of implantation induced lattice disturbances and defects is a difficult exercise and hampers the conversion of conductivity in GaN. Pulsed laser annealing is an effective annealing technique to recover lattice crystallinity and activate dopants with the preserved implanted profile. In this work, the effect of pulsed laser annealing on structural and optical recovery in high-dose magnesium (Mg) ion-implanted GaN has been investigated. The structural evolution and vibrational dynamics indicate an obvious structural recovery and partial strain release of Mg-implanted GaN during the pulsed laser annealing process, with a threshold laser fluence of 400 mJ/cm2, while rough surface structures are a result of the regrowth mechanism similar to liquid phase epitaxy. The enhanced donor–acceptor transition at 3.35 eV after pulsed laser irradiation is a sign of the effective activation of Mg from interstitial sites into the substitution of Ga ions. These results suggest that further optimization of the laser annealing technique has promising potential to manipulate the p-type conductivity of Mg-implanted GaN and to be implemented in GaN bipolar devices for practical applications.
Tunable topological edge transport in acoustic meta-atoms
Authors: Wang Yuanbo , Dong Yibao , Zhai Shilong , Ding Changlin , Luo Chunrong , Zhao Xiaopeng
Published: December 2020

Topological insulators (TIs) in condensed matter physics have been rapidly developed in acoustic fields and have enabled the controlling of acoustic waves in brand new ways recently. The current acoustic analogs of electronic TIs are mainly based on sonic crystal Bragg scattering. The practical applications of these TIs were restricted by a non-adjustable geometric structure, a wavelength equivalent scale, and a high and fixed frequency response. Here, we propose subwavelength acoustic TIs on the basis of negative metamaterials, which utilize local resonance different from Bragg scattering to design topologically protected acoustic propagation. We demonstrate the existence of band inversion by altering the ratio of the distance of the meta-atoms to the lattice constant. More importantly, the dispersion and edge states of the Dirac cones can offer tunability within a wide frequency range under a fixed lattice constant by adjusting the structural parameters of the meta-atoms. Theoretical analysis, numerical simulations, and experimental measurement verify the edge states of the acoustic TIs. The proposed acoustic topological metamaterials provide a flexible way of manipulating sound propagation.
New findings from old data: A semi-experimental value for the eQq of the nitrogen atom
Authors: Pinacho Pablo , Obenchain Daniel A. , Schnell Melanie
Published: December 2020

Nuclear quadrupole coupling arises from the interaction of the nuclear quadrupole moment with the electric field gradient. Thus, it is associated with electron occupancy and the electronic structure of molecules. We demonstrate a simple method for planar molecules based on a direct correlation between the out-of-plane quadrupole coupling constant and the electron occupancy in the p orbital perpendicular to the molecular plane. This method is applied to 98 molecular systems containing a 14N quadrupolar nucleus using data from more than 40 years of rotational spectroscopy and comparing the performance of three levels of theory from quantum-chemical computations. From this extensive dataset, we have analyzed chemical properties of molecules, such as the hybridization of the atom, and we could quantify the extent of polarization and resonance processes as well as physical characteristics of the quadrupolar nucleus, such as eQq. This is a constant, which represents the interaction in the hypothetical case of having a single electron in an electronic orbital at the isolated nucleus, and its value has been under debate for a long time. Here, the eQq value has been determined for the 14N nucleus, and the methodology to calculate it for other nuclei is provided.
CD4+ follicular regulatory T cells optimize the influenza virus–specific B cell response
Authors: Lu Yisi , Jiang Roy , Freyn Alec W. , Wang Jiawei , Strohmeier Shirin , Lederer Katlyn , Locci Michela , Zhao Hongyu , Angeletti Davide , O’Connor Kevin C. , Kleinstein Steven H. , Nachbagauer Raffael , Craft Joe
Published: December 2020

CD4+ follicular regulatory T (Tfr) cells control B cell responses through the modulation of follicular helper T (Tfh) cells and germinal center development while suppressing autoreactivity; however, their role in the regulation of productive germinal center B cell responses and humoral memory is incompletely defined. We show that Tfr cells promote antigen-specific germinal center B cell responses upon influenza virus infection. Following viral challenge, we found that Tfr cells are necessary for robust generation of virus-specific, long-lived plasma cells, antibody production against both hemagglutinin (HA) and neuraminidase (NA), the two major influenza virus glycoproteins, and appropriate regulation of the BCR repertoire. To further investigate the functional relevance of Tfr cells during viral challenge, we used a sequential immunization model with repeated exposure of antigenically partially conserved strains of influenza viruses, revealing that Tfr cells promote recall antibody responses against the conserved HA stalk region. Thus, Tfr cells promote antigen-specific B cell responses and are essential for the development of long-term humoral memory.
Modified Hawking effect from generalized uncertainty principle
Authors: Giné Jaume
Published: December 2020

We use the generalized uncertainty principle to compute the first correction to the Hawking temperature associated to Hawking effect. From this value we obtain a new evaporation time and entropy of any Schwarzschild black hole analyzing their expressions and consequences.
Conformal symplectic and relativistic optimization
Authors: França Guilherme , Sulam Jeremias , Robinson Daniel P , Vidal René
Published: December 2020

Arguably, the two most popular accelerated or momentum-based optimization methods in machine learning are Nesterov’s accelerated gradient and Polyaks’s heavy ball, both corresponding to different discretizations of a particular second order differential equation with friction. Such connections with continuous-time dynamical systems have been instrumental in demystifying acceleration phenomena in optimization. Here we study structure-preserving discretizations for a certain class of dissipative (conformal) Hamiltonian systems, allowing us to analyse the symplectic structure of both Nesterov and heavy ball, besides providing several new insights into these methods. Moreover, we propose a new algorithm based on a dissipative relativistic system that normalizes the momentum and may result in more stable/faster optimization. Importantly, such a method generalizes both Nesterov and heavy ball, each being recovered as distinct limiting cases, and has potential advantages at no additional cost.
Random matrix improved covariance estimation for a large class of metrics*
Authors: Tiomoko Malik , Bouchard Florent , Ginolhac Guillaume , Couillet Romain
Published: December 2020

Relying on recent advances in statistical estimation of covariance distances based on random matrix theory, this article proposes an improved covariance and precision matrix estimation method for a wide family of metrics. This method is shown to largely outperform the sample covariance matrix estimate and to compete with state-of-the-art methods, while at the same time being computationally simpler and faster. Applications to linear and quadratic discriminant analyses also show significant gains, therefore suggesting a practical relevance for statistical machine learning.
Wide flat minima and optimal generalization in classifying high-dimensional Gaussian mixtures
Authors: Baldassi Carlo , Malatesta Enrico M , Negri Matteo , Zecchina Riccardo
Published: December 2020

We analyze the connection between minimizers with good generalizing properties and high local entropy regions of a threshold-linear classifier in Gaussian mixtures with the mean squared error loss function. We show that there exist configurations that achieve the Bayes-optimal generalization error, even in the case of unbalanced clusters. We explore analytically the error-counting loss landscape in the vicinity of a Bayes-optimal solution, and show that the closer we get to such configurations, the higher the local entropy, implying that the Bayes-optimal solution lays inside a wide flat region. We also consider the algorithmically relevant case of targeting wide flat minima of the (differentiable) mean squared error loss. Our analytical and numerical results show not only that in the balanced case the dependence on the norm of the weights is mild, but also, in the unbalanced case, that the performances can be improved.
Quantitative reasoning and written communication. Competencies that evidence scientific thinking in university graduates
Authors: Ramirez-Leal P
Published: December 2020

The purpose of this manuscript was to characterize and analyse both the differences and similarities of the results between the different careers in a public university in eastern Colombia, in the state tests Saber Pro 2017, in the modules quantitative reasoning and written communication, skills needed to evidence the level of scientific thinking, very useful for professionals in engineering and science, especially for professionals in mathematics and physics. In this research, a univariate descriptive analysis was carried out, followed by a principal component analysis. Engineering programs tend to perform better in quantitative reasoning and those of social sciences and education in written communication. These results indicate that graduates of engineering and science programs have a level of scientific thinking more related to the exact and natural sciences.
Physical-technological change as a competitive factor in the clothing and footwear industry
Authors: Peña-Cáceres O , González Mendoza J , Vergel Ortega M
Published: December 2020

The investigation aimed to analyze the influence of physic-technological change as a factor of competitiveness in the textile and footwear industry in San José de Cúcuta, Colombia. The methodology follows a mixed approach supported by factorial, phenomenological and documentary analysis designs, using instruments such as interviews and surveys, scientific production databases and governmental and trade union reports of the sector. The physic-technological change was conceived by businessmen as a productive process, innovative, of social change, and transformation with associated factors of strategic management, culture of market planning, problem that solves, reach, control of success, materials such as systems based on silicone, polymers, panels and closed air pressure grilles, as well as improvements in sole material and use of recyclable material according to environmental policies, reduction of time of product development, marketing of the invention, resources, management of risk, productivity and competitiveness, depend on type of changes implemented or designed in companies of low, medium or high level and are associated with factor of competitiveness. It is concluded that technological change as a competitiveness factor allows maintaining or increasing market share and endogenous changes in productive and technological systems in the market.
Numerical and experimental study of the 3D flow in a graft-artery junction model
Authors: Ivanova Y F , Yukhnev A D , Gataulin Y A , Smirnov E M , Vrabiy A A , Vavilov V N
Published: December 2020

Vascular graft occlusion after implantation is one of the most urgent problems of vascular surgery. This paper presents results of numerical simulation and ultrasound/strain gauge measurements of the 3D pulsating flow of blood-mimicking fluid in a model of the junction of the graft with superficial femoral artery. The calculations have pointed, in particular, at occurrence of an extensive stagnant zone with low wall shear stresses near the graft-artery junction, which can accelerate the graft occlusion. Both the simulation and the ultrasound measurements have shown that a four-vortex flow structure forms just after the graft-artery junction zone, which transforms into a two-vortex flow structure further downstream. Numerical and experimental data on the pressure drop at the graft-artery junction model were in a good accordance.
The impact of surface boundary conditions on the formation of the Black Sea haline stratification from the numerical simulations
Authors: Senderov M V , Mizyuk A I
Published: December 2020

Following a series of studies of the formation of the Black Sea haline stratification by various initial and boundary conditions, three numerical experiments were performed. For this purpose, the previously performed experiment with a spatially uniform salinity of 12 %º was chosen (experiment 1). New simulations were carried out with heat fluxes on the surface (experiment 2) obtained in the department of VAO FSBSI FRC MHI. In addition to heat fluxes, a constant cyclonic tangential wind stress curl (experiment 3) and a tangential wind stress curl with a seasonal variation (experiment 4) were also set. The results of numerical simulations show that in all experiments where heat fluxes were set on the surface, the upper mixed layer appears. The depth of the halocline does not change and is at about 20 m. Also in all experiments the relation between the southward and northward currents are close. Water exchange through the southward current is almost two times greater than that through the northward.
3D simulation of single bubble dynamics in a microchannel with a complex cross-sectional shape
Authors: Solnyshkina O A , Pityuk Yu A , Bulatova A Z
Published: December 2020

The relevance of a study of bubbly liquid dynamics in porous media is due to a wide range of their use in technological and industrial processes. This work is dedicated to the numerical study of the dynamics of single incompressible bubbles in a viscous fluid flow in a microchannel with a cross-section in the shape of a deltoid. This geometry is due to the similarity with the domain between closely packed cylindrical fibers, forming a porous medium, for example, in the manufacturing of composite materials. In the present study for solving the considered problems, the boundary element method (BEM) was chosen as a basis of the numerical approach, since all calculations were associated only with boundaries. BEM is effective in studying 3D problems in the domains with complex geometry and modelling objects with arbitrary deformation. The influence of the initial radius of the bubble, its position relative to the channel centerline on the bubble deformation, relative velocity of the mass center of the bubble to the average flow velocity in the channel is considered.
Distribution of wall shear stress for a bubbly flow in rod assembly
Authors: Vorobyev M A , Kashinsky O N
Published: December 2020

The work is devoted to the experimental study of the wall shear stress in the vertical assembly of rods in a square arrangement for a bubble flow. The measurements were carried out using the electrodiffusion technique. The data obtained during the experiment show that the void fraction has a significant effect on the flow structure near the walls of the rods. The change in wall shear stress with distance from the spacer grid does not occur monotonously, in contrast to the single-phase case.
The main flow parameters characterising the liquid film suction process on the blade surface in a steam turbine
Authors: Gribin V G , Tishchenko V A , Popov V V , Tishchenko A A , Gavrilov I Yu , Alekseev R A
Published: December 2020

In this study, the process of liquid film suction from surfaces of steam blades is considered. The main goal of the investigation is to provide the list of nondimensional parameters characterizing this phenomenon. The complex nature of this process requires the consideration of various flow features occurring with the film. The influence of slot geometry, flow conditions and suction regimes are studied. As a result, the processes of film separation, transient breakup and interphase interaction are considered. Based on the obtained information, the set of nondimensional parameters is formulated. Their accounting will allow conducting correct research in laboratory conditions to transfer its results to a real turbine. The numerical modelling is performed to verify the findings, and the regime for the experimental rig providing the same non-dimensional parameters as for real turbine is selected.
Investigation of the cooling of a high-temperature surface by a dispersed coolant flow
Authors: Smorchkova Yu V , Ilyin V V , Shteling V S , Zakharenkov A V , Komov A T , Sherbakov P P
Published: December 2020

A modernized experimental setup diagram is presented for studying the cooling of a high-temperature surface with a dispersed coolant flow. The results of an experimental study of unsteady heat removal from a target with a temperature exceeding the Leidenfrost temperature are presented. The cooling curves are obtained, the regions of effective heat transfer are determined. The primary experimental data were obtained during stationary heat transfer in the following range of operating parameters of the coolant: mass water flow rate 0.0038 ÷ 0.0145 kg/s; water pressure 0.4 ÷ 0.2 MPa, induction heating power 7 ÷ 20 kW.
The calculating model of microstructured flat plate wettability during evaporation into the stagnation flow
Authors: Makarov M S , Makarova S N , Syuzaev A I
Published: December 2020

The results of the analysis of the problem of wetting the microstructured flat wall surface during adiabatic liquid evaporation into a boundary layer of air flowing at right angles are presented. The basic conservation laws are formulated in the form of differential equations that allow calculating the velocity and height of liquid rise in capillaries, wetting dynamics, depth and mass of the liquid in capillaries, and the evaporation surface area.
On steam bubble patterns in superheated liquids
Authors: Vladyko I V , Pil’nik A A , Chernov A A
Published: December 2020

This paper presents the results of numerical simulation of steam bubble growth in a uniformly superheated liquid. The numerical calculation scheme takes into account both inertial and thermal effects. The main regularities of the prosses are discussed by the example of different superheat levels and different liquids: water, mercury and glycerin. Simple estimations of characteristic times of the inertial and transition stages are offered.
The effect of boron, copper, and magnesium on the ignition of HEM containing aluminum powder
Authors: Sorokin I V , Korotkikh A G , Selikhova E A
Published: December 2020

The use of metal powder as fuel in high-energy materials (HEM) for propulsion is the most energy-efficient method to increase the burning rate, combustion temperature, and specific impulse. Typically, various dispersity aluminum powders are used in the HEM composition. To improve the ignition and combustion characteristics of the HEM composition it is advisable to use the catalysts (nonmetals, metals or their oxides). This paper presents the experimental data of the HEM samples ignition containing ammonium perchlorate, butadiene rubber, micron powders of aluminum, aluminum-magnesium alloy, as well as nanopowders of amorphous boron, aluminum-copper, and aluminum-boron mixtures. The use of aluminum-copper or aluminum-boron nanopowders in the HEM composition decreases the ignition delay time by 1.3–2.0 times in comparison with Al-based HEM during CO2 laser initiation. In the case of Al-Mg powder use, the ignition delay time is changed slightly.
Numerical simulation of melting of scattering ice in a single-phase Stephan problem
Authors: Savvinova N A , Sleptsov S D , Grishin M A
Published: December 2020

A numerical study of the formation of the temperature field and the melting rate of an ice layer scattering radiation, located on an opaque substrate during radiation heating was carried out. To solve the radiation part of the problem, a modified mean fluxes method was used, taking into account the volume absorption and scattering of radiation into the medium, as well as the selective nature of the radiation source. The effect of the spectral volumetric properties of ice on the melting and temperature increase of the non-irradiated side is shown. Comparison of calculation results with experimental data shows satisfactory agreement.