bluuebunny/crossref_metadata_2025 huggingface dataset:
New grape varieties for production of high-quality wines, and assessment methodology for varietal characteristics of the product
Authors: Guguchkina Tatiana , Antonenko Mikhail , Yakimenko Yelena
Published: October 2020

In recent years, Russian and international breeders have produced a great many of new varieties of Vitis vinifera grapes as well as interspecies hybrids, distinguished by a high quality of fruit and other useful economic and biological features. Having a big reserve of technologically important substances and hygienic factors of grapevine, the resistant varieties may prove especially efficient for the production of premium-class wines. The appearance of high-end Russian wines with protected geographical indication (PGI) and protected appellation of origin (PAO), first of all, fits in with the requirements of international markets. It is a necessary criterion for product quality and safety assurance at the highly competitive global market, and development of universally recognized brands. It also helps resolve a number of socio-economic issues, such as formation of winemaking culture, and production of wines of guaranteed quality from own grapes. This study is devoted to substantiating the necessity for development of methods of formation of single information databases on characteristic features of PGI and PAO wines, including their distinctive organoleptic, physical and chemical properties (extract components – the cation-anion composition, organic acids, total phenolic and anthocyanin content; unique colour characteristics), as well as the application of the system of organoleptic assessment of wines with the use of descriptive analysis of wine colour, flavour and taste. It is well-timed and relevant to determine the regularities of realization of the varietal potential of a grapevine plant in terms of climatic conditions of growing and geographical origin based on the study of the endogenous and exogenous components of wines with the use of the methods of high-performance capillary electrophoresis, spectral photometry, organoleptic analysis, and statistical techniques. This research generalizes and puts forth a contemporary view of varietal and geographical identification of wines. It is shown that the proposed research guideline is highly sought-after, and it is of fundamental and practical importance for the development of regional and national selection, genetic, viticultural and winemaking industries.
Advances in phenology and harvest characterization of the Chilean Vitis sp. germplasm collection and its use in table grape breeding
Authors: Salazar Erika , Durán Viviana , Araya Carolina , García Miguel , Barba Paola
Published: October 2020

Germplasm collection and characterization is essential for plant breeding. Chile holds a collection of 347 Vitis accessions at Instituto de Investigaciones Agropecuarias, La Platina, that have been successfully used to develop new table grape cultivars such as Maylen®. Located in the central valley of Chile, a section of the Vitis collection was characterized for two consecutive seasons for phenology as well as fruit quality parameters at harvest. In terms of phenology, the collections can be grouped in four main clusters, with a higher representation of individuals at the middle and late timing. Fruit phenotyping showed significant differences among wine and table grapes for cluster and berry weight, seed number and fresh seed weight, polar and equatorial diameters, as well as the ratio among these parameters. Interestingly, rachis weight, a novel parameter associated with fruit storage capacity, did not show differences among groups. Other novel traits, such as the combination of commercial seedleesness and berry equatorial diameters above 2cm were less represented, suggesting the need to create and introduce genetic variability for table grape breeding purposes.
Mixed infecting of grapevine with viruses in the commercial vineyards of the Crimean Peninsula
Authors: Risovannaya Valentina , Volodin Vitalii , Volkov Yakov , Stranishevskaya Elena , Goryslavets Svitlana
Published: October 2020

Viral infections cause the reduction of yields and efficiency of vine cultivation in all viticultural regions of the world. Simultaneous infecting with several viruses, the so-called mixed infection, can significantly increase the severity of symptoms. The article presents the results of study of mixed infecting of grapevine with viruses in the vineyards of the Crimean Peninsula during 2011-2020. More than 800 grapevine samples of 153 varieties selected in 23 vineyards of the Crimea were analyzed over the entire period of study. Presence of phytopathogenic viruses in the samples was determined by RT-PCR using virus specific primers. The share of 25.5 % of all the samples tested gave positive result for one or more of the following viruses: GFLV, GLRaV-1, GLRV-2, GLRaV-3, GFkV, GVA, GRSPaV, ArMV, GFLV. During the process of studyno vines affected by GVB virus were identified. Single-agent infection was found in 20% of the examined vines. The amount of vines affected by mixed infection was 5.48 % of all tested. In a mixed viral infection more common combinations are: GRSPaV/GFkV; GVA/GRSPaV; GVA/GLRaV-1/GRSPaV; GVA/GLRaV-3/GRSPaV. Vines were infected the most with GRSPaV and GFkV viruses, which is visually manifested in the form of mosaic leaf variegation, leaf chlorosis and the appearance of necrotic spots.
Efficiency of Percutaneous Stent Angioplasty in Renal Artery Stenosis – 15 Years of Experience at a Single Center
Authors: Guerreiro Helena , Avanesov Maxim , Dinnies Stefanie , Sehner Susanne , Schön Gerhard , Wenzel Ulrich , Adam Gerhard , Ittrich Harald , Regier Marc
Published: October 2020

Purpose To determine the therapeutic efficiency of percutaneous revascularization in renal artery stenosis (RAS), as well as the role of comprehensive factors such as patient selection and degree of artery stenosis, on clinical outcome.

Methods and Materials 101 patients with hemodynamically relevant RAS underwent percutaneous angioplasty (PTA). 65.7 % were male (mean age: 64 years; range: 18–84). The clinical data was retrospectively analyzed. The serum creatinine (Cr), glomerular filtration rate (GFR), and blood pressure (BP) levels pre- and postprocedural, between 6 months and 1 year, were retrospectively collected and statistically analyzed.

Results Follow-up data was available in 34 (33.7 %) and 28 patients (27.7 %) for Cr and MAP, respectively. A significant drop in mean arterial pressure (MAP) was observed on follow-up (mean –5.27 mmHg). Higher baseline Cr and MAP values showed a more pronounced drop in the follow-up (Cr: p 0.002; difference to baseline –0.25 mg/dL, 95 %CI:–0.36, –0.07 and BP p < 0.001; diff. to baseline –0.72 mmHg; 95 %CI: –1.4, –0.40). There was no association between comorbidities, gender, and degree of stenosis with renal and BP outcome. No significant improvement in renal function was observed on follow-up (mean Cr drop: –0.015 mg/dL). The age group 51–60 years showed a significant improvement in BP (p 0.030; diff. to baseline –19.2 mmHg; 95 %CI: –34, –4.3). There was a slight reduction in antihypertensive medication following angioplasty (0.2 fewer). Minor complications were recorded in five procedures (4.9 %).

Conclusion Percutaneous renal artery revascularization in the presence of atherosclerotic RAS is a safe procedure associated with a significant drop in post-procedural BP. No significant improvement in renal function was observed. Further prospective studies focused on patient selection are necessary.

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Citation Format
Review of Type III Endoleaks
Authors: Stoecker Jordan B. , Glaser Julia D.
Published: October 2020

Endoleak remains a significant challenge to endovascular aneurysm repair, particularly as evolving techniques and devices have allowed treatment of increasingly complex aneurysm anatomy with increasing number of device components. Intervention is recommended for both type I and III endoleaks due to their risk of rupture, and endovascular techniques are the favored modality with placement of a bridging endograft over the endoleak defect. Conversion to open surgical repair remains the definitive option in cases where less invasive methods have failed or are precluded. In this article, the authors review evidence on the etiology, incidence, diagnosis, and current techniques for type III endoleak management.
Surveillance Imaging following Endovascular Aneurysm Repair: State of the Art
Authors: Kim Stephanie H. , Litt Harold I.
Published: October 2020

Endovascular aneurysmal repair (EVAR) has become a prominent modality for the treatment of abdominal aortic aneurysm. Surveillance imaging is important for the detection of device-related complications, which include endoleak, structural abnormalities, and infection. Currently used modalities include ultrasound, X-ray, computed tomography, magnetic resonance imaging, and angiography. Understanding the advantages and drawbacks of each modality, as well available guidelines, can guide selection of the appropriate technique for individual patients. We review complications following EVAR and advances in surveillance imaging modalities.
The Association of Cesarean Skin Incision Length and Postoperative Wound Complications
Authors: Subramaniam Akila , Jauk Victoria , Saade George , Boggess Kim , Longo Sheri , Clark Erin A.S. , Esplin Sean , Cleary Kirsten , Wapner Ron , Letson Kellett , Owens Michelle Y. , Blackwell Sean , Szychowski Jeff M. , Andrews William W. , Tita Alan T.
Published: October 2020

Objective This study was aimed to evaluate the relationship between cesarean skin incision length and wound complications.

Study Design Planned secondary analysis of a multicenter double-blind randomized trial of adjunctive azithromycin versus placebo (in addition to standard cefazolin) in women ≥24 weeks undergoing cesarean delivery during labor or ≥4 hours after membrane rupture. Skin incision length (cm) was measured just prior to skin closure. The primary outcome was a composite of wound complications (wound infection, separation, seroma, hematoma, or dehiscence) up to 6 weeks of postpartum. Individual components of the composite were examined as secondary outcomes. Outcomes were compared between groups defined by the lowest (≤25th), middle (25–75th) and highest (>75th) incision length quartiles. Logistic regression was used to adjust for potential confounding variables.

Results Of the 2,013 women enrolled in the primary trial, 1,916 had recorded incision lengths and were included in this secondary analysis. The overall rate of composite wound complications was 7.8%. Median incision length was 15.0 cm (interquartile range: 14.0–16.5) with the lowest quartile defined as ≤14, middle as >14 to ≤16.5, and highest as >16.5 cm. Mean BMI, parity, use of staples, and duration of surgery differed significantly between the three incision length groups. In unadjusted analysis, the longest incision lengths were associated with an increased risk of the wound composite and wound infections (odds ratio [OR] = 2.27, 95% confidence interval [CI]: 1.43–3.60 and OR = 2.30, 95% CI: 1.27–4.15, respectively) compared with the shortest incision lengths. However, after multivariable adjustments, these associations were nullified. Additional analyses considering incision length as a continuous variable and using 10th/90th percentile cut-offs still did not suggest any associations with outcomes.

Conclusion Increasing skin incision length is not independently associated with an increased risk of postoperative wound complications.

Key Points
Self-Reported Effectiveness of e-Learning Classes during COVID-19 Pandemic: A Nation-Wide Survey of Pakistani Undergraduate Dentistry Students
Authors: Sarwar Huma , Akhtar Hira , Naeem Meshal Muhammad , Khan Javeria Ali , Waraich Khadija , Shabbir Sumaiya , Hasan Arshad , Khurshid Zohaib
Published: October 2020

Objectives The main aim of this study was to determine the undergraduate dental students’ self-reported effectiveness of online classes offered by various dental institutes of Pakistan.

Materials and Methods A cross-sectional study was conducted using an online survey. A pretested and validated questionnaire comprising of 31 questions was circulated among dental students. The study participants were inquired about the perceived level of accessibility of resources and the effectiveness of online teaching. The data was analyzed using SPSS version 24. Mann–Whitney U test and Kruskal–Wallis test were used for statistical analysis at p ≤0.05.

Results A total of 1,207 students from all over Pakistan responded. The majority of students was dissatisfied with the institutional learning management system and quality of learning resources available. Students were also dissatisfied with the level of training of teachers for online lectures. The worst rating was reported for questions related to the effectiveness of online classes (average rating: 3.83 and 3.781/5). First-year students reported poor interaction with teachers (p < 0.001) and strongly disagreed with the effectiveness of online classes (mean rating: 4.14 ± 0.935).

Conclusions The results from the present survey showed that dental students of Pakistan unanimously voiced dissatisfaction toward various elements of online teaching sessions. Findings from this survey will aid the academic institutes to establish proficient learning platforms focused on improving students` learning experience.
Role of Ultrahigh Frequency Ultrasound in Evaluating Experimental Flaps
Authors: Morarasu Stefan , Ghetu Nicolae , Coman Corneliu George , Morarasu Bianca Codrina , Boicu Daniel , Spiridon Irene Alexandra , Gardikiotis Ioannis , Danciu Mihai , Pieptu Dragos
Published: October 2020

Background Experimental flap follow-up needs faster, safer, and less invasive techniques that can be easily correlated to clinical procedures. For this reason, we aimed to test the role of ultrahigh frequency ultrasound in follow-up of flap viability. Further on, we aimed to analyze if the chimeric groin flap can be mobilized in a sandwiched position without affecting its vascular supply by twisting its pedicle.

Methods A total of 12 male Wistar rats, split into three groups, were used. Group A (n = 4) had the chimeric groin flap repositioned in a sandwich position on the anterior abdominal wall and underwent ultrahigh frequency ultrasound follow-up at days 10 and 14. Group B (n = 4) also had the flaps sandwiched, however, at day 14 the vascularity of flaps was proven by infusion of nontargeted ultrasound contrast agents, after which flaps were sent for histological analysis. Group C (C1 n = 2, C2 n = 2) was the control group. In C1 the chimeric groin flap was harvested and sent for histology on day 0, acting as a histological benchmark of flap viability, and in C2 the chimeric groin flap was re-sutured in its anatomical position and after 14 days, flaps were harvested and sent for histological analysis, acting as a direct control for Group B.

Results Ultrasound showed constant vascular flow in both adipose and skin flaps in the sandwiched position. Microbubble study showed diffuse perfusion within flaps. Ultrasound measurements of flow velocity, flap volume, and percentage of vascularity showed a decrease in flap volume and increase in vascularity over 14 days. Histology showed similar viability in both groups.

Conclusion Ultrahigh frequency ultrasound may be a valuable tool for postoperative flap assessment, while the chimeric flap can be moved freely in a sandwich position making it suitable for adding tissue substitutes within its components.
Lean Management Im Krankenhaus: Die 10 Grundprinzipien von Lean Hospital Logistics
Authors: Kriegel Johannes
Published: October 2020

Lean Management ist ein Gestaltungsansatz, um Prozesse kontinuierlich zu optimieren, damit Wertschöpfungsketten effizient und effektiv gestaltet sowie primäre und unterstützende Prozesse miteinander vernetzt werden. Die 10 Grundprinzipien des Lean Hospital Logistics bieten ein breites Spektrum an Anwendungsmöglichkeiten in der stationären Patientenversorgung und der Krankenhausorganisation.
Benchmark-Programm mit Herzzentren: Optimale Prozeduren schonen Krankenhausressourcen
Authors: Rößing Sabine
Published: October 2020

Die aktuelle Pandemie rückt das Thema Prozessqualität und Effizienz in den Fokus. Vor dem Hintergrund begrenzter Ressourcen an Material, belegbaren Krankenhausbetten und vor allem qualifiziertem Personal werden niedrige Komplikationsraten und eine möglichst geringe Verweildauer ohne Einbußen am medizinischen Ergebnis wichtiger denn je.
Hygiene und Prozesssicherheit Durch E-Learning: Ausbildung durch digitales Lernen
Authors: Weißmantel Udo
Published: October 2020

100 Jahre Leben – 100 Jahre Lernen. Das war schon immer aktuell – vor 100 Jahren genauso wie heute. Aber noch nie war das Lernen zugänglicher und leichter als heute. Dank der neuen Technik werden innovative Lernmethoden und Kanäle geschaffen, die das Lernen überall, zu jeder Tageszeit und für viele Menschen gleichzeitig ermöglichen.
Aufbereitung von Medizinprodukten: Agile AEMP im Universitätsspital Zürich – ein Erfahrungsbericht
Authors: Lader Annette , Schläpfer Christian , Meyer Thorsten , Ryter Samuel
Published: October 2020

Die in die Jahre gekommene Zentralsterilisation auf dem Campus des Universitätsspitals Zürich (USZ) ist seit Juni abgelöst worden von der neuen Aufbereitungseinheit für Medizinprodukte (AEMP) im Logistik- und Servicezentrum in Schlieren – eine der europaweit modernsten Anlagen ihrer Art. Die Autoren berichten von dem Weg dorthin.
Super Camassa–Holm-type systems associated to the Kuper–Ramond–Schwarz superalgebra
Authors: Ge Yanyan
Published: October 2020

We describe a class of super integrable systems with a local bi-super-Hamiltonian structure, including super Camassa–Holm-type systems, which can be realized as Euler-type systems on the dual of the Kuper–Ramond–Schwarz superalgebra.
Photodynamics of methyl-vinyl Criegee intermediate: Different conical
intersections govern the fates of syn/anti configurations
Authors: Li Ya-zhen , Yang Jia-wei , Makroni Lily , Wang Wen-liang , Liu Feng-yi
Published: October 2020

Methyl vinyl ketone oxide, an unsaturated four-carbon Criegee intermediate produced from the ozonolysis of isoprene has been recognized to play a key role in determining the tropospheric OH concentration. It exists in four configurations (anti-anti, anti-syn, syn-anti, and syn-syn) due to two different substituents of saturated methyl and unsaturated vinyl groups. In this study, we have carried out the electronic structure calculation at the multi-configurational CASSCF and multi-state MS-CASPT2 levels, as well as the trajectory surface-hopping nonadiabatic dynamics simulation at the CASSCF level to reveal the different fates of syn/anti configurations in photochemical process. Our results show that the dominant channel for the S1-state decay is a ring closure, isomerization to dioxirane, during which, the syn(C-O) configuration with an intramolecular hydrogen bond shows slower nonadiabatic photoisomerization. More importantly, it has been found for the first time in photochemistry of Criegee intermediate that the cooperation of two heavy groups (methyl and vinyl) leads to an evident pyramidalization of C3 atom in methyl-vinyl Criegee intermediate, which then results in two structurally-independent minimal-energy crossing points (CIs) towards the syn(C-O) and anti(C-O) sides, respectively. The preference of surface hopping for a certain CI is responsible for the different dynamics of each configuration.
Direct observation of transient species generated from protonation and deprotonation of the lowest triplet of p-nitrophenylphenol
Authors: Long Jing , Ye Zhao , Du Yong , Zheng Xu-ming , Xue Jia-dan
Published: October 2020

Photo-induced proton coupled electron transfer (PCET) is essential in the biological, photosynthesis, catalysis and solar energy conversion processes. Recently, p-nitrophenylphenol (HO-Bp-NO2) has been used as a model compound to study the photo-induced PCET mechanism by using ultrafast spectroscopy. In transient absorption spectra both singlet and triplet states were observed to exhibit PCET behavior upon laser excitation of HO-Bp-NO2. When we focused on the PCET in the triplet state, a new sharp band attracted us. This band was recorded upon excitation of HO-Bp-NO2 in aprotic polar solvents, and has not been observed for p-nitrobiphenyl which is without hydroxyl substitution. In order to find out what the new band represents, acidic solutions were used as an additional proton donor considering the acidity of HO-Bp-NO2. With the help of results in strong (~10−1 mol/L) and weak (~10−4 mol/L) acidic solutions, the new band is identified as open shell singlet O-Bp-NO2H, which is generated through protonation of nitro O in 3HO-Bp-NO2 followed by deprotonation of hydroxyl. Kinetics analysis indicates that the formation of radical O-Bp-NO2 competes with O-Bp-NO2H in the way of concerted electron-proton transfer and/or proton followed electron transfers and is responsible for the low yield of O-Bp-NO2H. The results in the present work will make it clear how the 3HO-Bp-NO2 deactivates in aprotic polar solvents and provide a solid benchmark for the deeply studying the PCET mechanism in triplets of analogous aromatic nitro compounds.
Bias-polarity dependent electroluminescence from a single platinum phthalocyanine molecule
Authors: Farrukh Aftab , Tian Xiao-jun , Kong Fan-fang , Yu Yun-jie , Jing Shi-hao , Chen Gong , Zhang Yao , Liao Yuan , Zhang Yang , Dong Zhen-chao
Published: October 2020

By using scanning tunneling microscope induced luminescence (STML) technique, we investigate systematically the bias-polarity dependent electroluminescence behavior of a single platinum phthalocyanine (PtPc) molecule and the electron excitation mechanisms behind. The molecule is found to emit light at both bias polarities but with different emission energies. At negative excitation bias, only the fluorescence at 637 nm is observed, which originates from the LUMO→HOMO transition of the neutral PtPc molecule and exhibits stepwise-like increase in emission intensities over three different excitation-voltage regions. Strong fluorescence in region (I) is excited by the carrier injection mechanism with holes injected into the HOMO state first; moderate fluorescence in region (II) is excited by the inelastic electron scattering mechanism; and weak fluorescence in region (III) is associated with an up-conversion process and excited by a combined carrier injection and inelastic electron scattering mechanism involving a spin-triplet relay state. At positive excitation bias, more-than-one emission peaks are observed and the excitation and emission mechanisms become complicated. The sharp molecule-specific emission peak at ~911 nm is attributed to the anionic emission of PtPc− originated from the LUMO+1→LUMO transition, whose excitation is dominated by a carrier injection mechanism with electrons first injected into the LUMO+1 or higher-lying empty orbitals.
Photodissociation dynamics of AlO at 193 nm using time-sliced ion
velocity imaging
Authors: Li Fang-fang , Ma Yu-jie , Liu Jia-xing , Wang Guan-jun , Wang Feng-yan
Published: October 2020

The photodissociation dynamics of AlO at 193 nm is studied using time-sliced ion velocity mapping. Two dissociation channels are found through the speed and angular distributions of aluminum ions: one is one-photon dissociation of the neutral AlO to generate Al(2Pu)+O(3Pg), and the other is two-photon ionization and then dissociation of AlO+ to generate Al+(1Sg)+O(3Pg). Each dissociation channel includes the contribution of AlO in the vibrational states v=0-2. The anisotropy parameter of the neutral dissociation channel is more dependent on the vibration state of AlO than the ion dissociation channel.
Unveiling defect-mediated carrier dynamics in few-layer
MoS2 prepared by ion exchange method via ultrafast Vis-NIR-MIR
spectroscopy
Authors: Chi Zhen , Chen Hui-hui , Chen Zhuo , Chen Hai-long
Published: October 2020

Defect-mediated processes in two-dimensional transition metal dichalcogenides have a significant influence on their carrier dynamics and transport properties, however, the detailed mechanisms remain poorly understood. Here, we present a comprehensive ultrafast study on defect-mediated carrier dynamics in ion exchange prepared few-layer MoS2 by femtosecond time-resolved Vis-NIR-MIR spectroscopy. The broadband photobleaching feature observed in the near-infrared transient spectrum discloses that the mid-gap defect states are widely distributed in few-layer MoS2 nanosheets. The processes of fast trapping of carriers by defect states and the following nonradiative recombination of trapped carriers are clearly revealed, demonstrating the mid-gap defect states play a significant role in the photoinduced carrier dynamics. The positive to negative crossover of the signal observed in the mid-infrared transient spectrum further uncovers some occupied shallow defect states distributed at less than 0.24 eV below the conduction band minimum. These defect states can act as effective carrier trap centers to assist the nonradiative recombination of photo-induced carriers in few-layer MoS2 on the picosecond time scale.
The extended Granger causality analysis for Hodgkin–Huxley neuronal models
Authors: Cheng Hong , Cai David , Zhou Douglas
Published: October 2020

How to extract directions of information flow in dynamical systems based on empirical data remains a key challenge. The Granger causality (GC) analysis has been identified as a powerful method to achieve this capability. However, the framework of the GC theory requires that the dynamics of the investigated system can be statistically linearized; i.e., the dynamics can be effectively modeled by linear regressive processes. Under such conditions, the causal connectivity can be directly mapped to the structural connectivity that mediates physical interactions within the system. However, for nonlinear dynamical systems such as the Hodgkin–Huxley (HH) neuronal circuit, the validity of the GC analysis has yet been addressed; namely, whether the constructed causal connectivity is still identical to the synaptic connectivity between neurons remains unknown. In this work, we apply the nonlinear extension of the GC analysis, i.e., the extended GC analysis, to the voltage time series obtained by evolving the HH neuronal network. In addition, we add a certain amount of measurement or observational noise to the time series to take into account the realistic situation in data acquisition in the experiment. Our numerical results indicate that the causal connectivity obtained through the extended GC analysis is consistent with the underlying synaptic connectivity of the system. This consistency is also insensitive to dynamical regimes, e.g., a chaotic or non-chaotic regime. Since the extended GC analysis could in principle be applied to any nonlinear dynamical system as long as its attractor is low dimensional, our results may potentially be extended to the GC analysis in other settings.
Local uniformly upper semi-continuity of random attractor for g-Navier–Stokes equation
Authors: Li Fuzhi , Xu Dongmei
Published: October 2020

This paper is concerned with the locally uniform convergence from a family of pullback random attractors to a deterministic attractor. We establish criteria by using joint-pathwise convergence of the cocycles, collective locally uniform compactness, and eventually deterministic of the random attractors. As an application of the abstract result, it is shown that the family of random attractors for the stochastic g-Navier–Stokes equation is local uniformly upper semi-continuous as the density of random noise tends to zero.
Preliminary experimental research of a Ka-band radial transit time oscillator
Authors: Zhang Jun , Wang Haitao , Dang Fangchao , Qian Baoliang , Ge Xingjun , Chen Siyao , Lv Yankui
Published: October 2020

Radial transit time oscillator (RTTO) can be relied on to generate effective coherent electromagnetic radiation in the millimeter wave domain. In this paper, the preliminary experimental research on a Ka-band RTTO is reported for the first time. In experiments, the radial electron beam emitted from the knife edge of the disk cathode is guided by the radial magnetic field. The bombardment trace on the nylon target verifies the emission and transportation uniformity of the radial e-beam. When the diode voltage is 410 kV, the beam current is 7.8 kA, and the magnetic field is 0.6 T, the RTTO can output microwaves with the power of 320 MW and the frequency of 31.35 GHz. As the diode voltage increases from 350 kV to 430 kV, the output microwave power will grow accordingly. Taking the ohmic loss into consideration, the experimental results are in agreement with the simulation ones.
The challenge of stochastic Størmer–Verlet thermostats generating correct statistics
Authors: Finkelstein Joshua , Cheng Chungho , Fiorin Giacomo , Seibold Benjamin , Grønbech-Jensen Niels
Published: October 2020

In light of the recently developed complete GJ set of single random variable stochastic, discrete-time Størmer–Verlet algorithms for statistically accurate simulations of Langevin equations [N. Grønbech-Jensen, Mol. Phys. 118, e1662506 (2020)], we investigate two outstanding questions: (1) Are there any algorithmic or statistical benefits from including multiple random variables per time step and (2) are there objective reasons for using one or more methods from the available set of statistically correct algorithms? To address the first question, we assume a general form for the discrete-time equations with two random variables and then follow the systematic, brute-force GJ methodology by enforcing correct thermodynamics in linear systems. It is concluded that correct configurational Boltzmann sampling of a particle in a harmonic potential implies correct configurational free-particle diffusion and that these requirements only can be accomplished if the two random variables per time step are identical. We consequently submit that the GJ set represents all possible stochastic Størmer–Verlet methods that can reproduce time step-independent statistics of linear systems. The second question is thus addressed within the GJ set. Based on numerical simulations of complex molecular systems, as well as on analytic considerations, we analyze apparent friction-induced differences in the stability of the methods. We attribute these differences to an inherent, friction-dependent discrete-time scaling, which depends on the specific method. We suggest that the method with the simplest interpretation of temporal scaling, the GJ-I/GJF-2GJ method, be preferred for statistical applications.
Generalized correlation-based dynamical network analysis: a new high-performance approach for identifying allosteric communications in molecular dynamics trajectories
Authors: Melo Marcelo C. R. , Bernardi Rafael C. , de la Fuente-Nunez Cesar , Luthey-Schulten Zaida
Published: October 2020

Molecular interactions are essential for regulation of cellular processes from the formation of multi-protein complexes to the allosteric activation of enzymes. Identifying the essential residues and molecular features that regulate such interactions is paramount for understanding the biochemical process in question, allowing for suppression of a reaction through drug interventions or optimization of a chemical process using bioengineered molecules. In order to identify important residues and information pathways within molecular complexes, the dynamical network analysis method was developed and has since been broadly applied in the literature. However, in the dawn of exascale computing, this method is frequently limited to relatively small biomolecular systems. In this work, we provide an evolution of the method, application, and interface. All data processing and analysis are conducted through Jupyter notebooks, providing automatic detection of important solvent and ion residues, an optimized and parallel generalized correlation implementation that is linear with respect to the number of nodes in the system, and subsequent community clustering, calculation of betweenness of contacts, and determination of optimal paths. Using the popular visualization program visual molecular dynamics (VMD), high-quality renderings of the networks over the biomolecular structures can be produced. Our new implementation was employed to investigate three different systems, with up to 2.5M atoms, namely, the OMP-decarboxylase, the leucyl-tRNA synthetase complexed with its cognate tRNA and adenylate, and respiratory complex I in a membrane environment. Our enhanced and updated protocol provides the community with an intuitive and interactive interface, which can be easily applied to large macromolecular complexes.
Organ-on-a-disc: A platform technology for the centrifugal generation and culture of microphysiological 3D cell constructs amenable for automation and parallelization
Authors: Schneider Stefan , Erdemann Florian , Schneider Oliver , Hutschalik Thomas , Loskill Peter
Published: October 2020

Organ-on-a-chip (OoC) systems have evolved to a promising alternative to animal testing and traditional cell assays in drug development and enable personalization for precision medicine. So far, most OoCs do not fully exploit the potential of microfluidic systems regarding parallelization and automation. To date, many OoCs still consist of individual units, integrating only one single tissue per chip, and rely on manual, error-prone handling. However, with limited parallelization and automation, OoCs remain a low-throughput technology, preventing their widespread application in industry. To advance the concept of microphysiological systems and to overcome the limitations of current OoCs, we developed the Organ-on-a-disc (Organ-Disc) technology. Driven only by rotation, Organ-Discs enable the parallelized generation and culture of multiple 3D cell constructs per disc. We fabricated polydimethylsiloxane-free Organ-Discs using thermoplastic materials and scalable fabrication techniques. Utilizing precisely controllable centrifugal forces, cells were loaded simultaneously into 20 tissue chambers, where they formed uniform cell pellets. Subsequently, the cells compacted into dense 3D cell constructs and were cultured under vasculature-like perfusion through pump- and tubing-free, centrifugal pumping, solely requiring a low-speed rotation (<1 g) of the Organ-Disc. Here, we provide a proof-of-concept of the Organ-Disc technology, showing the parallelized generation of tissue-like cell constructs and demonstrating the controlled centrifugal perfusion. Furthermore, Organ-Discs enable versatile tissue engineering, generating cell constructs with a customizable shape and a layered multi-cell type structure. Overall, the Organ-Disc provides a user-friendly platform technology for the parallelization and automation of microphysiological systems, bringing this technology one-step closer to high-throughput applications in industry.
Magnetic anisotropies of La–Co substituted M-type Sr hexaferrites studied by 57Fe Mössbauer spectroscopy with external magnetic fields
Authors: Nagasawa Nobumoto , Oura Momoko , Ikeda Shugo , Waki Takeshi , Tabata Yoshikazu , Nakamura Hiroyuki , Kobayashi Hisao
Published: October 2020

Magnetoplumbite-(M)-type hexaferrites are the most widely used base materials of permanent magnets. La–Co substitution in these M-type Sr hexaferrites improves these magnetic anisotropies. By 57Fe Mössbauer spectroscopy using the single-crystalline samples, we have investigated the Fe electronic states in the La–Co substituted M-type Sr hexaferrites, Sr1−xLaxFe12−yCoyO19, as a function of an external magnetic field to discuss the enhancement of these magnetic anisotropies. All observed 57Fe Mössbauer spectra were well analyzed using the five subspectra corresponding to the five crystallographic nonequivalent Fe sites. At one site of these five Fe sites, the 2a Fe site, the extracted hyperfine interaction parameters clearly show the Co substitution and external magnetic field dependences, revealing the increments of the 3d electrons in the Fe ions, which are caused by the substitution of Co2+ ions for Fe3+ ions at the neighbor 4f1 Fe site. This hybridization between the Fe ions and the Co ions induces the non-negligible unquenched orbital momentum in the Fe ions at the 2a Fe site. Our findings represent an enhancement of the magnetic anisotropies in Sr1−xLaxFe12−yCoyO19.
Hydration processes of barium chloride: Size-selected anion photoelectron spectroscopy and theoretical calculations of BaCl2-water clusters
Authors: Wei Zhi-You , Yang Li-Jiang , Xu Hong-Guang , Farooq Umar , Xu Xi-Ling , Gao Yi-Qin , Zheng Wei-Jun
Published: October 2020

In order to understand the hydration processes of BaCl2, we investigated BaCl2(H2O)n− (n = 0–5) clusters using size-selected anion photoelectron spectroscopy and theoretical calculations. The structures of neutral BaCl2(H2O)n clusters up to n = 8 were also investigated by theoretical calculations. It is found that in BaCl2(H2O)n−/0, the Ba–Cl distances increase very slowly with the cluster size. The hydration process is not able to induce the breaking of a Ba–Cl bond in the cluster size range (n = 0–8) studied in this work. In small BaCl2(H2O)n clusters with n ≤ 5, the Ba atom has a coordination number of n + 2; however, in BaCl2(H2O)6–8 clusters, the Ba atom coordinates with two Cl atoms and (n − 1) water molecules, and it has a coordination number of n + 1. Unlike the previously studied MgCl2(H2O)n− and CaCl2(H2O)n−, negative charge-transfer-to-solvent behavior has not been observed for BaCl2(H2O)n−, and the excess electron of BaCl2(H2O)n− is mainly localized on the Ba atom rather on the water molecules. No observation of Ba2+–Cl− separation in current work is consistent with the lower solubility of BaCl2 compared to MgCl2 and CaCl2. Considering the BaCl2/H2O mole ratio in the saturated solution, one would expect that about 20–30 H2O molecules are needed to break the first Ba–Cl bond in BaCl2.
Effect of reflection patterns on converging shock waves generated by underwater electrical wire array explosion
Authors: Liu Zhigang , Qian Dun , Zou Xiaobing , Wang Xinxin
Published: October 2020

The transition from regular to irregular reflection when the expanding shock waves generated by underwater electrical wire array explosion collided with each other was investigated using the numerical method. Shadowgraph diagnostics were applied for imaging of the expansion of exploding wires and the propagation of shock waves, and the results agreed well with the self-consistent hydrodynamic simulations based on the cylindrical piston model. The simulation results show that the transition angle from regular to irregular reflection for strong shock is smaller than weak shock, which is the principal cause of the self-alignment phenomenon in the convergence process of stronger shock waves. Also, the nonlinear superposition of pressure peak behind shock wave, caused by the formation and interaction of Mach stems, is analyzed using the oblique shock wave theory.
Hall conductance and the statistics of flux insertions in gapped interacting lattice systems
Authors: Kapustin Anton , Sopenko Nikita
Published: October 2020

We study charge transport for zero-temperature infinite-volume gapped lattice systems in two dimensions with short-range interactions. We show that the Hall conductance is locally computable and is the same for all systems that are in the same gapped phase. We provide a rigorous version of Laughlin’s flux-insertion argument, which shows that for short-range entangled systems, the Hall conductance is an integer multiple of e2/h. We show that the Hall conductance determines the statistics of flux insertions. For bosonic short-range entangled systems, this implies that the Hall conductance is an even multiple of e2/h. Finally, we adapt a proof of quantization of the Thouless charge pump to the case of infinite-volume gapped lattice systems in one dimension.
Percolation and nanosecond fluctuators in V2O3 films within the metal–insulator transition
Authors: Chen Liyang , Zhou Panpan , Kalcheim Yoav , Schuller Ivan K. , Natelson Douglas
Published: October 2020

Vanadium sesquioxide (V2O3) exhibits a metal–insulator transition (MIT) at 160 K between a low temperature, monoclinic, antiferromagnetic Mott insulator and a high temperature, rhombohedral, paramagnetic, metallic phase. In thin films, a percolative transition takes place over a finite temperature range of phase coexistence. We study the fluctuating dynamics of this percolative MIT by measuring voltage noise spectra at both low frequencies (up to 100 kHz) and radio frequencies (between 10 MHz and 1 GHz). Noise intensity quadratic in bias is observed in the MIT region, as expected for resistive fluctuations probed nonperturbatively by the current. The low frequency noise resembles flicker-type 1/fβ noise, often taking on the form of Lorentzian noise dominated by a small number of fluctuators as the volume fraction of the insulating phase dominates. Radio frequency noise intensity also quadratic in the bias current allows the identification of resistance fluctuations with lifetimes below 1 ns, approaching timescales seen in non-equilibrium pump–probe studies of the transition. We find quantitative consistency with a model for fluctuations in the percolative fraction. The thermodynamics of the MIT suggests that dominant fluctuations are ones that alter small volumes affecting the connectivity of domain boundaries. This noise serves as a sensitive and nonperturbative probe for the dynamics of switching phenomena in this system.
Correlations between first-principles calculations and electric properties of HfO2:Al2O3 alloys for metal–insulator–metal (MIM) capacitor applications
Authors: Khaldi O. , Jomni F. , Gonon P.
Published: October 2020

The electronic structure and optical properties of monoclinic HfO2 (m-HfO2) and HfO2:Al2O3 alloys, from the density functional theory (DFT), are investigated. The calculated lattice parameters and optical properties of m-HfO2 are consistent with the experimental data. Upon alloying with Al2O3 (more than 25%), we observe that the bandgap of Hf-aluminate (HfAlO) increases. Moreover, some doping states in the top and bottom valence bands are induced, which enhance the visible absorption of HfO2. From the impedance spectroscopy analysis, it is observed that 90% of the Al2O3 content in HfO2 induces a reduction of oxygen vacancies (and ac conductivity) as well as an increase in the dielectric constant as compared to pure HfO2. In addition, from the J–V and C–V variations, both current density and capacitance voltage nonlinearities are reduced. The conduction mechanisms of HfO2 and HfAlO dielectrics are systematically investigated. According to the J–E plots, parameters like the optical dielectric constant and the effective barrier height are extracted. Results are consistent with the DFT calculations and show that the Hf0.1Al0.9O device may constitute a potential candidate for metal–insulator–metal capacitor applications.
Spin valves as magnetically switchable spintronic THz emitters
Authors: Fix Mario , Schneider Robert , Michaelis de Vasconcellos Steffen , Bratschitsch Rudolf , Albrecht Manfred
Published: October 2020

In this Letter, we demonstrate that spin valve systems consisting of a magnetically soft free Fe layer and a magnetically hard Fe fixed layer pinned by an antiferromagnetic Ir23Mn77 layer, which are separated by a Pt or W spacer, are efficient switchable spintronic terahertz (THz) emitters. We show that a small external magnetic field on the order of 10 mT is sufficient to switch the magnetization orientation of the free layer and, therefore, to change the relative magnetization orientation of the two Fe layers. This goes along with a change in the THz RMS amplitude by up to more than one order of magnitude and allows fast switching of the emitter from a high to a low THz power state and vice versa.
An alternative phase-field interfacial tension force representation for binary fluid systems
Authors: Vasilopoulos Yannis
Published: October 2020

The Navier–Stokes/Cahn–Hilliard (NSCH) system of equations has been extensively used for investigating the dynamics of two-phase flows of Newtonian fluids. However, the accurate calculation of interfacial tension via NSCH has been perceptibly doubted, and thus, a successive solution of NSCH equations is rarely not accompanied by mesh adaptation techniques and complex numerical schemes. In this work, it is demonstrated that the cause of such a miscalculation of the interfacial tension is inherent when following the conventional way of coupling the Navier–Stokes with the Cahn–Hilliard equation in their dimensionless form, where the capillary number is defined by assuming that the fluid/fluid interface is flat and at equilibrium. Hence, an alternative NSCH model was developed for the more accurate computation of interfacial tension that does not rely on any such a priori assumptions, and it uses a more abstract coupling by accounting for the distribution of the binary system’s energy on the interfacial region. This model was implemented on two different cases: (i) an investigation of the effects of inertia and capillarity on the deformation of liquid drops in simple shear flow and (ii) a study of an interfacial instability due to viscosity stratification. To solve the set of governing equations, implicit time integration schemes based on finite differences were further developed and implemented. The results regarding the topological evolution of the fluid/fluid interface from both cases were additionally cross-validated with other methods from the literature as well as with the conventional NSCH model. The comparison suggests that our NSCH model indeed remedies the standard NSCH model, without the need of mesh adaptation or any complex numerical scheme, by more accurately computing the interfacial tension for binary systems consisting of incompressible, immiscible, and Newtonian fluids.
So you want to hire a professor!
Authors: Anderson Matthew E.
Published: October 2020

The process for finding a new educator can be daunting, yet nearly every university goes through the same procedural steps. Here’s a practical guide from the faculty side.
Healthcare providers' perceptions of the challenges and opportunities to engage Chinese migrant women in contraceptive counselling: a qualitative interview study
Authors: Dolan Hankiz , Li Mu , Bateson Deborah , Thompson Rachel , Tam Chun Wah Michael , Bonner Carissa , Trevena Lyndal
Published: October 2020

Background
In Australia, there are many culturally and linguistically diverse communities and Chinese migrants make up one of the largest. Yet, little is known about healthcare providers’ (HCPs) unique experiences in providing contraceptive care for Chinese migrant women. There is minimal research into the HCPs’ perceptions of challenges or opportunities in engaging Chinese migrant women in informed and shared decision-making processes during contraceptive counselling. The aim of this study is to explore HCPs’ experiences of providing contraceptive care for Chinese migrant women, their perceptions of women’s care needs when choosing contraceptive methods, as well as their own needs in supporting women’s decision-making. Methods: Semi-structured interviews were conducted with 20 HCPs in Sydney, Australia who had substantial experience in providing contraceptive services to Chinese women who were recent migrants. Transcribed audio-recorded data were analysed using thematic analysis. Results: Four main themes were identified, including: ‘Are you using contraception?’: the case for being proactive and opportunistic; ‘Getting the message across’: barriers to communication; ‘Hormones are unnatural?’: women favouring non-hormonal methods; and ‘Word of mouth’: social influence on contraceptive method choice. Conclusions: In order to facilitate informed choice and shared decision-making with Chinese migrant women during contraceptive counselling, broader health system and community-level strategies are needed. Such strategies could include improving HCPs’ cultural competency in assessing and communicating women’s contraceptive needs; providing professional interpreting services and translated materials; and improving women’s health literacy, including their contraceptive knowledge and health system awareness.