bluuebunny/crossref_metadata_2025 huggingface dataset:
Research on Near Space Plasma Vacuum Environmental Simulation Technology
Authors: Fu Chunyu , Dong Yize
Published: September 2018

The operation reliability of spacecraft in orbitis affected by the interaction with space plasma, research on the space enviroment by advanced testing method is important. It is costly to carry out research and analysis with space flight. Therefore, tests using ground vacuum environment simulation system are of significance. This paper proposed the structure design, simulation analysis and numerical calculation methods for the three subsystems of plasma environment simulation system, including vacuum vessel, vacuum acquisition and vacuum measurement and control. The simulation results show that the maximum stress of the vacuum vessel is 113.2MPa , and the maximum deformation is 0.59mm , at the same time, vacuum technology index, structural stability and human-machine interaction performance of the system can meet the experimental research requirement.
Finite Element Analysis of Space Science Experimental Equipment Based on HyperMesh and Nastran
Authors: Sinian Huang , Anping Wang
Published: September 2018

In the design process of space science experimental equipment, in order to better grasp the dynamic characteristics of the structure, a large number of finite element analysis is needed. This paper comprehensively use HyperMesh and Nastran to establish a set of finite element analysis process for space science experimental equipment, combine the advantages of each software to perform finite element analysis comprehensively, which greatly improves the accuracy and efficiency of the finite element analysis, the problems of this kind of engineering analysis has certain reference value.
The description of two new species of Chloromyxum from skates in the Argentine Sea reveals that a limited geographic host distribution causes phylogenetic lineage separation of myxozoans in Chondrichthyes
Authors: Cantatore Delfina María Paula , Irigoitia Manuel Marcial , Holzer Astrid Sibylle , Bartošová-Sojková Pavla , Pecková Hana , Fiala Ivan , Timi Juan Tomás
Published: September 2018

During a survey on the myxosporean fauna of Rajiformes from the Atlantic coast of Argentina, in waters off Buenos Aires Province (34°–42°S; 53°–62°W), the gall bladders of 217 specimens belonging to seven species of skates, representatives of two families, were examined. As a result, three species of Chloromyxum Mingazzini, 1890, namely C. atlantoraji n. sp., C. zearaji n. sp. and C. riorajum Azevedo, Casal, Garcia, Matos, Teles-Grilo and Matos, 2009 were found infecting three endemic host species, the spotback skate Atlantoraja castelnaui (Arhynchobatidae), the yellownose skate Zearaja chilensis (Rajidae) and the Rio skate Rioraja agassizii (Arhynchobatidae), respectively. These species were described based on myxospore morphology and morphometry characterization, as well as by providing their small subunit ribosomal DNA (SSU rDNA) sequences. The SSU rDNA-based phylogenetic analyses showed that these three species constituted a well-established monophyletic subclade within the marine Chloromyxum clade, while branches subtending the other Chloromyxum species were poorly resolved or unresolved, independently of the host taxonomic identities (Carchariniformes, Myliobatiformes, Orectolobiformes, Pristiophoriformes, Rajiformes, Squaliformes and Torpediniformes) and/or host geographic distribution (Atlantic coast of Portugal, Atlantic coast of the USA, Australian waters or Mediterranean Sea). The possible causes of these discrepancies are discussed, providing new insights into the phylogeny of the marine Chloromyxum clade.
Aktualisierte S3-Leitlinie Colitis ulcerosa der Deutschen Gesellschaft für Gastroenterologie, Verdauungs- und Stoffwechselkrankheiten (DGVS)
Authors:   Authors,   Collaborators:
Published: September 2018

Die neue S3-Leitlinie Colitis stellt aktuelle und evidenzbasierte Empfehlungen zur Behandlung der Colitis ulcerosa zur Verfügung. Sie ersetzt damit die Vorläuferversion von 2011. Neben den neuesten Erkenntnissen zu Diagnostik und Therapie werden insbesondere infektiologische Probleme, chirurgische und Ernährungsmaßnahmen aufgegriffen. Unter der Federführung der DGVS wurde die Leitlinie gemeinsam mit 10 weiteren Fachgesellschaften und Patientenvertretern erarbeitet mit dem Ziel, eine optimale interdisziplinäre Versorgung der Patienten zu gewährleisten.
Orthorexia nervosa: Verhaltensauffälligkeit oder neue Störungskategorie?
Authors: Strahler Jana , Stark Rudolf
Published: September 2018

Zahlreiche epidemiologische Studien zeigen, dass es sich bei Orthorexia nervosa, der zwanghaften Fixierung auf gesundes Essen, um ein bekanntes und verbreitetes Phänomen in verschiedenen Ländern und Kulturen handelt (Prävalenzen zwischen 1 und 7% in der deutschen Allgemeinbevölkerung). Die Diskussion, ob es sich dabei jedoch lediglich um ein gesellschaftliches Phänomen bzw. Verhaltensauffälligkeit handelt, eine (subklinische) Essstörung oder eine Zwangsstörung, oder ob man dieses Verhalten zur Gruppe der Verhaltenssüchte zählen sollte, steht dabei ganz am Anfang. Nur wenige Studien beschäftigen sich mit dieser differenzialdiagnostischen Abgrenzung. Unter Beachtung der Uneinigkeit in Bezug auf die Definition des Phänomens legen aktuelle Studien am ehesten eine Klassifizierung im Rahmen der Essstörungen nahe. Zweifel entstehen v. a. aus dem deutlichen Überlappungsgrad zu anderen Lebensstilmerkmalen. Ähnlich rar sind Studien, die die klinische Relevanz eines orthorektischen Essverhaltens nachzeichnen sowie mögliche Entstehungsmechanismen thematisieren. Alter und Geschlecht spielen nach aktuellen Erkenntnissen eine eher untergeordnete Rolle. Studien zum Einfluss von Bildung und Gewicht deuten auf einen schwachen bis moderaten U-förmigen Zusammenhang mit orthorektischen Verhaltensweisen. Ebenso werden Aspekte wie Schönheitsideal, Perfektionismus sowie Fitness- und Gesundheitsorientierung immer wieder als relevant beschrieben. Studien zu neuropsychologischen und biologischen Korrelaten fehlen fast komplett. Der vorliegende Artikel gibt einen Überblick über den aktuellen Forschungsstand, zeigt verschiedene Erklärungsansätze und reflektiert kritisch über den aktuellen Wissensstand.
Treatments of Choice for Isolated, Full-Thickness Tears of the Posterior Cruciate Ligament: A Nationwide Survey of Orthopaedic Surgeons
Authors: Schumaier Adam , Minoughan Chelsea , Jimenez Andrew , Grawe Brian
Published: September 2018

The ideal treatment for isolated, full-thickness tears of the posterior cruciate ligament (PCL) is uncertain. The purpose of this study was to determine how the majority of orthopaedic surgeons treat isolated, full-thickness tears of the PCL. In July 2017, a 17-question multiple-choice survey regarding the treatment of isolated, full-thickness tears of the PCL was emailed to 3,500 orthopaedic sports medicine surgeons with membership in the American Orthopaedic Society for Sports Medicine. Responders answered multiple-choice questions related to indications, technique, graft choice, bracing, and weight-bearing status following reconstruction. Answer choices were then analyzed against surgeon-specific variables. The survey was completed by 663 orthopaedic surgeons. Of the responders, 93% were fellowship trained in sports medicine with an average practice duration of 13 years. The total number of PCLs reconstructed per surgeon was low, 11.6. On average, surgeons estimate they reconstruct the PCL in only 22% of patients with full-thickness tears. The two most common surgical indications were functional limitations and failure of physical therapy. The reconstruction of choice involves a transtibial approach (63%) with a single bundle (87%) allograft (83%) of the Achilles tendon (51%). The postoperative brace is typically locked in extension (66%), and weight-bearing is delayed for 3.8 weeks. Of the surgeons with the fewest years of experience, 39% use all-inside, 89% use allograft, and 24% use dynamic bracing. Compared with surgeons with the most years of experience, only 16% use all-inside (p < 0.01), 57% use allograft (p < 0.01), and 11% use dynamic bracing (p = 0.01). Isolated, full-thickness tears of the PCL are rare injuries that are infrequently reconstructed. The most common indications for reconstruction are functional limitations and failure of conservative management. Most surgeons' treatment of choice for reconstruction involves a transtibial approach with a single bundle Achilles allograft and a postoperative brace locked in extension. On average, weight-bearing is prolonged for 3.8 weeks. The all-inside technique, allograft, and dynamic bracing are becoming more popular.
Implementation and Outcomes of Universal Delayed Umbilical Cord Clamping at Term
Authors: Wesevich Victoria , Tuuli Methodius , Macones George , Cahill Alison , Rhoades Janine
Published: September 2018

Objective To evaluate the implementation of an institutional protocol for universal delayed umbilical cord clamping (DCC) at term on maternal, neonatal, and umbilical cord blood gas outcomes.

Study Design This is a retrospective cohort study of singleton term gestations from April through July 2017. On June 1, 2017, a protocol was implemented for DCC in all deliveries. Outcomes were compared between patients delivered prior to and those delivered after implementation. The primary outcome was postpartum hemorrhage (PPH). Secondary outcomes were additional adverse maternal, neonatal, and umbilical cord blood gas outcomes. Multivariable logistic regression was used to adjust for potential confounders.

Results Of 682 patients, 341 were delivered preprotocol and 341 were delivered postprotocol. After implementation, there was 91.8% adherence to the protocol. Overall, there was no significant difference in PPH between patients delivered preprotocol and those delivered postprotocol (8.2 vs. 13.2%; adjusted relative risk [aRR]: 1.26, 95% confidence interval [CI]: 0.98–1.51). There was a significant decrease in the ability to obtain paired arterial and venous umbilical cord blood gases from preprotocol to postprotocol (83 vs. 63.6%; aRR: 0.62 [95% CI: 0.50–0.76]). There were no significant differences in abnormal umbilical cord blood gases or neonatal outcomes.

Conclusion We did not find an increased risk of adverse outcomes associated with the widespread use of DCC.
Identification of a Pivotal Period in the Oral Feeding Progression of Preterm Infants
Authors: Fucile Sandra , Phillips Sarah , Bishop Kelly , Jackson Meagan , Yuzdepski Taylor , Dow Kimberly
Published: September 2018

Objective Preterm infants are at risk of encountering oral feeding difficulties which impede on the transition to independent oral feeds. The objective of this study was to identify a pivotal period where regressions are most likely to occur during their oral feeding progression.

Study Design This is a retrospective study on 101 infants born <35 weeks' gestation. The sample was separated into two groups, infants who experienced a regression during their oral feeding progression and those who did not. A pivotal period was defined as a time frame where setbacks (a decrease in oral feed attempts by one) are most likely to occur at the start (1–2 oral feed attempts per day), middle (3–5 oral feed attempts per day), or end (6–8 oral feed attempts per day) of the oral feeding progression.

Result Eighty-two percent of infants experienced setbacks; 45% of all setbacks occurred at the middle time frame (p = 0.03). Infants' degree of maturity and enteral tube feeding intolerances were associated with increased occurrence of setbacks (p = 0.04).

Conclusion The midpoint in the oral feeding progression is a pivotal period where setbacks are most likely to occur. This time frame can be used by clinicians to evaluate oral-motor skills for earlier provision of interventions to reduce the occurrence of oral feeding difficulties in this high-risk population.
Antibiotic Use in Pregnancy, Abnormal Fetal Growth, and Development of Gestational Diabetes Mellitus
Authors: Catov Janet , Deihl Tiffany , Feghali Maisa , Scifres Christina , Mission John
Published: September 2018

Objective Antibiotics are commonly used in pregnancy. Prior studies have indicated that antibiotic use in pregnancy may affect birth weight, whereas data in nonpregnant individuals suggest that antibiotic exposure may increase diabetes risk. We evaluated the impact of antibiotic prescriptions during pregnancy on the prevalence of small for gestational age (SGA) and large for gestational age (LGA) birth weight and gestational diabetes mellitus (GDM).

Study Design This retrospective cohort study of 12,551 women who delivered at a large academic medical center between 2012 and 2014 assessed the number and type of antibiotic prescriptions prior to GDM testing using the electronic medical record. SGA and LGA birth weight and GDM rates were compared among women who were or were not prescribed antibiotics.

Results Overall, 3,991 (31.8%) of 12,551 patients received at least one antibiotic prescription. After covariate adjustment, no differences existed in risk of SGA (adjusted odds ratio [aOR]: 1; 95% confidence interval [CI]: 0.88–1.15; p = 0.94), LGA (aOR: 1; 95% CI: 0.86–1.17; p = 0.97), or GDM (aOR: 0.90; 95% CI: 0.72–1.13; p = 0.36) between women who were or were not prescribed antibiotics.

Conclusion Antibiotic use does not affect the risk of SGA or LGA birth weight or GDM in pregnant women. These results provide reassurance regarding the use of antibiotics when clinically indicated in pregnancy.
Stillbirth and Live Birth at Periviable Gestational Age: A Comparison of Prevalence and Risk Factors
Authors: Carmichael Suzan , Blumenfeld Yair , Mayo Jonathan , Profit Jochen , Shaw Gary , Hintz Susan , Stevenson David
Published: September 2018

Objective We compared the prevalence of and risk factors for stillbirth and live birth at periviable gestational age (20–25 weeks).

Study Design This is a cohort study of 2.5 million singleton births in California from 2007 to 2011. We estimated racial–ethnic prevalence ratios and used multivariable logistic regression for risk factor comparisons.

Results In this study, 42% of deliveries at 20 to 25 weeks' gestation were stillbirths, and 22% were live births who died within 24 hours. The prevalence of delivery at periviable gestation was 3.4 per 1,000 deliveries among whites, 10.9 for blacks, 3.5 for Asians, and 4.4 for Hispanics. Nonwhite race–ethnicity, lower education, uninsured status, being U.S. born, older age, obesity, smoking, pre-pregnancy hypertension, nulliparity, interpregnancy interval, and prior preterm birth or stillbirth were all associated with increased risk of both stillbirth and live birth at 20 to 25 weeks' gestation, compared with delivery of a live birth at 37 to 41 weeks.

Conclusion Inclusion of stillbirths and live births in studies of deliveries at periviable gestations is important.
Apgar Scores at 10 Minutes and Outcomes in Term and Late Preterm Neonates with Hypoxic-Ischemic Encephalopathy in the Cooling Era
Authors: Ayrapetyan Marina , Talekar Kiran , Schwabenbauer Kathleen , Carola David , Solarin Kolawole , McElwee Dorothy , Adeniyi-Jones Susan , Greenspan Jay , Aghai Zubair
Published: September 2018

Objective To determine the short-term outcomes (abnormal brain magnetic resonance imaging [MRI]/death) in infants born with a 10-minute Apgar score of 0 who received therapeutic hypothermia and compare them with infants with higher scores.

Study Design This is a retrospective review of 293 neonates (gestational age ≥ 35 weeks) born between November 2006 and October 2015 admitted with hypoxic-ischemic encephalopathy who received therapeutic hypothermia. Results of brain MRIs were assessed by the basal ganglia/watershed scoring system. Short-term outcomes were compared between infants with Apgar scores of 0, 1 to 4, and ≥5 at 10 minutes.

Results Eight of 17 infants (47%) with an Apgar of 0 at 10 minutes survived, having 4 (24%) without abnormalities on the brain MRI and 7 (41%) without severe abnormalities. There was no significant difference in the combined outcomes of “death/abnormal MRI” and “death/severe abnormalities on the MRI” between infants with Apgar scores of 0 and 1 to 4. Follow-up data were available for six of eight surviving infants, and none had moderate or severe neurodevelopmental impairment.

Conclusion In the cooling era, 47% of infants with no audible heart rate at 10 minutes and who were admitted to the neonatal intensive care unit survived; 24% without abnormalities on the brain MRI and 41% without severe abnormalities.
Non-governmental organizations as key partners in mental health in Europe
Authors: Baumann A. E.
Published: September 2018

The shift towards a rights-based approach to health which has taken place over the past decade has strengthened the role of civil society and their organizations in raising and claiming the entitlements of different social groups. It has become obvious that non-governmental organizations (NGOs) are central to any successful multi-stakeholder partnership, and they have become more recognized as key actors in health policy and programme development and implementation. There is a broad spectrum of NGOs active in the area of mental health in Europe which aim to empower people with mental health problems and their families, give them a voice in health policy development and implementation and in service design and delivery, to raise awareness and fight stigma and discrimination, and foster implementation of obligations set by internationally agreed mental health policy documents. With the endorsement of the Mental Health Action Plan 2013-2020 (20) and the European Mental Health Action Plan (19) stakeholders agree to strengthen capacity of service user and family advocacy groups and to secure their participation as partners in activities for mental health promotion, disorder prevention and improving mental health services.
Psychische Erkrankungen und Migration - es ist nicht so, wie es erscheint
Authors: Mokhtari Nejad R. , Eser-Valeri D. , Falkai P.
Published: September 2018

Fragestellung: Aufgrund der besonderen Rahmenbedingungen innerhalb der Europäischen Union kommt es zu einer zunehmenden Internationalisierung der Patienten im psychiatrischen Versorgungsalltag. Dabei existieren zahlreiche Barrieren für die Inanspruchnahme der Versorgungsleistungen bei Migrantinnen und Migranten. Im Rahmen einer Fallvignette sollen die Herausforderungen bei der psychiatrischen Behandlung von Patienten mit Migrationshintergrund exemplarisch erläutert werden.

Methode: Ein 48-jähriger aus dem Irak stammender Patient wurde wegen eines chronischen Schmerzsyndroms und ausgeprägter depressiver Symptomatik in der Ambulanz für Menschen mit Migrationshintergrund der LMU München zur weiterführenden Diagnostik vorgestellt. Offensichtlich führten psychosoziale Belastungsfaktoren, wie der Verlust seiner Frau und seiner Tochter, zu depressiven Episoden. Die Schmerzsymptomatik des Patienten konnte nicht geklärt werden.

Zusammenfassung: Mit diesem Fall verdeutlichen wir drei wesentliche Faktoren, die für Schwierigkeiten im diagnostischen Setting bei Patienten mit Migrationshintergrund verantwortlich sein können.

Sprachverständigung, kultursensible Versorgung und Vermeidung von Stereotypisierung sind elementar, um die individuelle Situation der Patienten mit Migrationshintergrund zu verstehen und die Behandlung zu verbessern.
Broadband antireflection coatings adopting 3-layer homogeneous dielectric materials for birefrigent sapphire waveplate in millimeter-wave band
Authors: Zhu Cheng
Published: September 2018

The Design, fabrication, and measurement of a broadband 3-layer antireflection (AR) coating on birefrigent sapphire waveplate in the cryogenic environment are reported in this paper. The proposed ARC design laminates 3 different uniform dielectric materials (n=1.25, 1.81, and 2.45) and bonds them together with the sapphire waveplate in the vacuum heating oven in the cleanroom. The transmission of coated waveplate in both fast and slow axis are greatly improved from averagely around 55.8% to 94.8% and from 61.2% to 98.8% in two axis across from 105 GHz to 300 GHz (the relative bandwidth approaching 100%), meanwhile the ARC also has the merit of incident angle robustness for the homogeneous property of the dielectrics. The experimental results are in excellent agreement with theoretical calculations after the curve fitting technique. The proposed design method of ARC reported in this paper provides us a novel and straightforward method to design the recipe of ARC using conventional dielectric materials, which could be potentially applied for various waveplates and other devices made of any type of material.
Note: Multi-gap gas switch with low trigger-threshold voltage by mounting resistors and capacitors in parallel with switch gaps
Authors: Jiang Hongyu , Sun Fengju , Wang Zhiguo , Jiang Xiaofeng , Cong Peitian , Yin Jiahui , Huang Tao , Luo Weixi , Zhang Tianyang , Zhai Rongxiao
Published: September 2018

To reduce the trigger threshold voltage of the multi-gap gas switch used for linear transformer drivers, a method is proposed by mounting resistors and capacitors in parallel with the switch gaps. Based on the circuit model of the six-gap gas switch, the gap voltage distribution during the triggering process is analyzed. When the multi-gap gas switch is triggered, the voltage distribution between gaps is mainly determined by the stray capacitance between electrodes. In such condition, the trigger voltage is not fully applied on the trigger gap, and as a consequence, a higher trigger voltage is required for obtaining a low jitter. The effects of capacitor parameters on the triggering characteristics of the switch are experimentally investigated. Compared with the original switch design, the results indicate that at a charging voltage of ±80 kV and operating at 60% of the self-breakdown voltage, the trigger voltage is reduced from 110 kV to 75 kV while the 3.2 ns jitter of the switch is preserved.
Laboratory time-resolved X-ray diffractometry for investigation of reversible structural changes induced in single crystals by external electric field
Authors: Marchenkov N. V. , Kulikov A. G. , Petrenko A. A. , Pisarevsky Yu. V. , Blagov A. E.
Published: September 2018

Time-resolved technique of X-ray diffraction curve measurement was implemented at a laboratory X-ray source using a high-speed data acquisition system. The time resolution of up to 100 µs was achieved via this X-ray diffractometry technique in the experiment of rocking curve dynamics measurement in a piezoelectric lanthanum-gallium silicate crystal under the influence of high voltage periodic pulsed electric field with an amplitude of 3.08 kV/mm corresponding to the pre-breakdown state. This perturbation caused a quick angular shift of the rocking curve caused by crystal lattice deformation due to the piezoelectric effect. The absence of the diffraction curve broadening effect was shown as well as the absence of the other significant relaxation-like variations of the curve parameters which are inherent for the migration of charge carriers (ions or vacancies) under the external electric field.
High mobility ultra-thin crystalline indium oxide thin film transistor using atomic layer deposition
Authors: Lee Jongchan , Moon Jaehyun , Pi Jae-Eun , Ahn Seong-Deok , Oh Himchan , Kang Seung-Youl , Kwon Kwang-Ho
Published: September 2018

Stoichiometric crystalline binary metal oxide thin films can be used as channel materials for transparent thin film transistors. However, the nature of the process used to fabricate these films causes most binary metal oxide thin films to be highly conductive, making them unsuitable for channel materials. We overcame this hurdle by forming stoichiometric ultra-thin (5 nm) crystalline In2O3 films by using a thermal atomic layer deposition method. Specifically, (3-(dimethylamino)propyl)dimethylindium was used as a liquid precursor and ozone as an oxygen source to grow In2O3 thin films at a high growth rate of 0.06 nm/cycle. Adjustment of the deposition processing temperature followed by annealing in an oxygen atmosphere enabled us to fully crystallize the film into a cubic bixbyite structure with the retained stoichiometry. The transparent crystalline ultra-thin In2O3-based bottom-gate thin film transistors showed excellent and statistically uniform switching characteristics such as a high Ion/Ioff ratio exceeding 107, a high linear mobility of 41.8 cm2/V s, a small subthreshold swing of 100 mV/dec, and a low hysteresis of 0.05 V. Our approach offers a straightforward scheme, which is compatible with oxide electronics, for fabricating a transparent metal oxide device without resorting to complicated oxide compositional strategies.
Toroidal drift modes driven by the magnetic drift resonances
Authors: Weiland Jan , Liu Chuan Sheng , Zagorodny Anatoly
Published: September 2018

Here, we find that the kinetic and fluid linear drift resonances have several similarities. The reason for our interest in this is that our fluid model has recently been shown to be exact for drift waves and other modes in that frequency range. Thus, transport is driven by the fluid linear growth rate and our drift wave system behaves like a cold beam-plasma system although it has a finite temperature. A main similarity is that neither fluid nor kinetic responses should be expanded in the curvature in the bulk interior of tokamaks. That we can use the fluid response close to the magnetic drift resonance is a consequence of the fact that the closure is exact. A systematic orbit integration technique is introduced for deriving the fluid model and evaluating the effects of nonlinearities.
Brownian ensemble of random-radius buoyancy vortices and Maxwell velocity distribution in a turbulent convective mixed-layer
Authors: Vulfson A. N. , Borodin O. O.
Published: September 2018

The stochastic ensemble of convective thermals (vortices), forming the fine structure of a turbulent convective atmospheric layer, is considered. The proposed ensemble model assumes all thermals in the mixed-layer to have the same determinate buoyancies and considers them as solid spheres of variable volumes. The values of radii and vertical velocities of the thermals are assumed random. The motion of the stochastic system of convective vortices is described by the nonlinear Langevin equation with a linear drift coefficient and a random force, whose structure is known for a system of Brownian particles. The probability density of the thermal ensemble in velocity phase space is shown to satisfy an associated K-form of the Fokker-Planck equation with variable coefficients. Maxwell velocity distribution of convective thermals is constructed as a steady-state solution of a simplified Fokker-Planck equation. The obtained Maxwell velocity distribution is shown to give a good approximation of experimental distributions in a turbulent convective mixed-layer.
Spinning disk atomization: Theory of the ligament regime
Authors: Li Yuan , Sisoev Grigori M. , Shikhmurzaev Yulii D.
Published: September 2018

A method of the mathematical modeling of the spinning disk atomization process as a whole, from the film flow on a rotating disk to the drop formation and detachment from the ends of the ligaments spiralling out of the disk’s rim, is formulated and the key results illustrating its implementation are described. Being one of the most efficient nozzle-free atomization techniques, spinning disk atomization is used in many applications, ranging from metallurgy to pharmaceutical industry, but until now its design and optimization remain empirical which is time consuming and costly. In the present work, the entire spinning disk atomization process is, for the first time, modelled mathematically by (a) utilizing all known analytic results regarding its elements, notably the film flow on the disk and the dynamics of outgoing spiral jets, where the flow description can be simplified asymptotically and (b) using the full-scale numerical simulation of the three-dimensional unsteady free-boundary flow in the transition zone near the disk’s rim which brings these elements together. The results illustrating the developed modeling approach reveal some previously unreported qualitative features of the spinning disk atomization process, such as the drift of the outgoing ligaments with respect to the disk, and elucidate the influence of physical factors on the size distribution of the drops and, where this is the case, satellite droplets. The comparison of the obtained results with available experimental data confirms the validity of the assumptions used in the modeling.
Modulating the electronic properties of perovskite via σ–π interfacial interactions: A computational study
Authors: Li Fengyu , Yi Fuzhao , Gao Junfeng , Zhang Haijun , Chen Zhongfang
Published: September 2018

By means of density functional theory computations, we comprehensively investigated the stability and electronic properties of the hybrid CH3NH3PbI3 (methylammonium lead iodide, MAPI)/graphene heterojunctions, where the MAPI layer was adopted with MAI (methylammonium iodide)-terminations. Our computations demonstrated that the σ–π interfacial interactions make the contact very stable, and such interactions lead to charge redistribution and concomitant internal electric field in the interface, which is beneficial for the electron-hole separation.
Effects of hawkmoth-like flexibility on the aerodynamic performance of flapping wings with different shapes and aspect ratios
Authors: Shahzad Aamer , Tian Fang-Bao , Young John , Lai Joseph C. S.
Published: September 2018

The effect of hawkmoth-like flexibility on the aerodynamic hovering performance of wings at a Reynolds number of 400 has been assessed by conducting fluid structure interaction simulations incorporating a finite difference based immersed boundary method coupled with a finite-element based structure solver. The stiffness distribution of a hawkmoth forewing was mapped onto three wing shapes (r¯1 = 0.43, 0.53, and 0.63) defined by the radius of the first moment of wing area each with aspect ratios, AR = 1.5, 2.96, 4.5, and 6.0 using elliptic mesh generation, the Jacobi method for iterations, and the concept of the barycentric coordinate system. The results show that there is a dominant chordwise deformation at AR = 1.5, and the wings also deform in the spanwise direction and their tips deviate from the horizontal stroke plane as AR increases. At AR = 1.5, 2.96, and 4.5, flexibility increases the mean lift (up to 39%, 18%, and 17.6%, respectively) for all wing shapes. At AR = 6.0, the r1¯ = 0.53 and 0.63 flexible wings give lesser lift than the rigid equivalents because of negative lift or small positive lift during the early stroke as the vortical structures remain on the bottom surface. This is attributed to the rapid pitch-down rotation, lesser stroke angular velocity than the rigid wing, and upward motion of the wingtip, away from the horizontal stroke plane. From the design perspective, the anisotropic flexible wings (except r1¯ = 0.53 and 0.63 with AR = 6.0) can be used in micro aerial vehicles for high lift requirements, such as for a high payload. Results here show that in nature, the hawkmoth wings with r1¯ and AR of 0.43-0.44 and 2.73-2.92, respectively, appear to have a combination of the shape, AR, and flexibility that optimizes power economy.
Linear positive and negative magnetoresistance in topological insulator Bi2Se3 flakes
Authors: Zhang Huachen , Li Hui , Wang Huanwen , Cheng Guanghui , He Hongtao , Wang Jiannong
Published: September 2018

The linear positive magnetoresistance (MR) and negative MR are emerging as intriguing phenomena in topological materials. Here, we report the magnetotransport properties of topological insulator Bi2Se3 flakes with different thicknesses grown by chemical vapor deposition. A non-saturating positive MR is observed in the perpendicular fields (B⊥I), while an evident negative MR is observed in the parallel fields (B//I). Both the positive MR and negative MR show a linear magnetic field dependence at high magnetic fields (B > 8 T). In addition, two types of carriers are extracted from the nonlinear Hall resistance measurements, which are attributed to the Bi2Se3 bulk electrons and the electron accumulation layer at the surface or Bi2Se3/SiO2 interface, respectively. The conductivity fluctuations in the accumulation layer are believed to be the origin for the observation of positive MR in the perpendicular fields and negative MR in the parallel fields with linear and non-saturating characteristics.
A Relativistic Complex Optical Potential Calculation for Electron–Beryllium Scattering: Recommended Cross Sections
Authors: McEachran R. P. , Blanco F. , García G. , Brunger M. J.
Published: September 2018

We report results from the application of the relativistic complex optical potential (ROP) method to electron–beryllium scattering. The energy range of this study was 0–5000 eV, with the results for the integral elastic cross sections, momentum transfer cross sections, summed discrete electronic-state excitation integral cross sections, and total ionisation cross sections (TICSs) being reported. However we will largely focus our discussion here on the TICS, due to its importance in simulating the plasma action on beryllium (Be) in the international thermonuclear reactor. The current level of agreement between the various theoretical approaches to calculating the TICS is well summarised in the work of Maihom et al. [Eur. Phys. J. D 67, 2 (2013)] and Blanco et al. [Plasma Sources Sci. Technol. 26, 085004 (2017)], with the level of accord between them being quite marginal. As a consequence, we revisit this problem with improved scattering potentials over those employed in the work of Blanco et al. In addition, we present results from an application of the binary-encounter-Bethe theory for the electron–Be TICS. We find a quite significant improvement in the level of agreement between the TICS from our new ROP calculation and the earlier B-spline R-matrix and convergent close coupling results [O. Zatsarinny et al., J. Phys. B: At., Mol. Opt. Phys. 49, 235701 (2016)], compared to that reported in the work of Blanco et al. As a result of this improved level of accord, we propose here a recommended TICS for e+Be scattering, as well as for the elastic integral and summed electronic-state excitation cross sections, which also incorporates uncertainty estimates for their validity.
NMR studies on the coupling of ion and water dynamics on various time and length scales in glass-forming LiCl aqueous solutions
Authors: Schneider S. , Vogel M.
Published: September 2018

We combine 1H, 2H, and 7Li NMR methods to investigate the dynamics of water molecules and lithium ions in LiCl aqueous solutions over wide ranges of time and length scales down to their glass transitions. Structural relaxation times τ and self-diffusion coefficients D reveal that water and lithium dynamics are faster for lower salt content at ambient temperatures, while the differences vanish upon cooling when fractional freezing leads to similar salt concentrations in the remaining liquid phases. Relaxation times and diffusion coefficients of water molecules agree with those of lithium ions in the weakly supercooled regime, indicating that the dynamics are strongly coupled. Furthermore, non-Arrhenius temperature dependence is found and the Stokes-Einstein relation is obeyed in this temperature range. However, we observe various decoupling phenomena for the motion of the constituents and for dynamics on different length scales in the deeply supercooled regime. Most notably, the rotational motion of the water molecules does not follow the glassy slowdown of the studied salt solutions below ∼145 K, but it rather resembles that in nanoscopic confinement, molecular solutions, and high-density amorphous ice at low temperatures. This common low-temperature water dynamics is characterized by large-angle reorientation and Arrhenius temperature dependence.
Configurable ultra-low operating voltage resistive switching between bipolar and threshold behaviors for Ag/TaOx/Pt structures
Authors: Huang Xu , Jiang Kang'an , Niu Yiru , Wang Renzhi , Zheng Diyuan , Dong Anhua , Dong Xinyuan , Mei Chunlian , Lu Jing , Liu Shuai , Gan Zhikai , Zhong Ni , Wang Hui
Published: September 2018

An ultra-low operating voltage bipolar resistive switching is observed in Ag/TaOx/Pt devices. They show a typical bipolar resistive switching with both low operating voltages and high cycling endurance when the compliance current (ICC) is 0.3 mA. Moreover, the operating voltage is considerably influenced by the grain size of the film. The VForming increases dramatically when the grain size exceeds a critical value. Meanwhile, the bipolar resistive switching and threshold switching in Ag/TaOx/Pt devices can be converted to each other by changing the magnitude of the ICC. Finally, a model based on the migration of Ag+ is proposed to explain the ultra-low operating voltage and the critical effect of grain size. The model is proved by simulation. These findings may lead to ultra-low power memories and contribute to a further understanding of the resistive switching effect.
A highly flexible molecule: The peculiar case of ethynyl isothiocyanate HCCNCS
Authors: Sun Wenhao , Davis Rebecca L. , Thorwirth Sven , Harding Michael E. , van Wijngaarden Jennifer
Published: September 2018

The rotational spectrum of the parent isotopic species of HCCNCS, along with those of three 13C singly substituted variants and one 34S minor isotopologue, has been observed with high resolution using Fourier transform microwave spectroscopy from 4 to 26 GHz. Based on the observed spectral pattern and assignment of the 14N nuclear quadrupole hyperfine structure, the geometry of HCCNCS is effectively linear, which is further supported by the observation of ℓ-type doubling for rotational transitions in an excited bending state of the parent HCCNCS. The experimental observations are supported by high level quantum chemical calculations using the coupled-cluster singles and doubles model augmented by a perturbative correction for triple excitations, CCSD(T), level of theory that reveal an extremely shallow potential energy well along the CNC bending angle with a surprising basis set dependence.
Theoretical insight into the role of urea in the hydrolysis reaction of NO2 as a source of HONO and aerosols
Authors: Lv Shuang , Bai Feng-Yang , Pan Xiu-Mei , Zhao Liang
Published: September 2018

Environmental contextUrea is an important component of dissolved organic nitrogen in rainfall and aerosols, but the sources and the mechanisms of its production are not well understood. This computational study explores the effects of urea and water on the hydrolysis of NO2 and urea nitrate production. The results will aid our interpretation of the role of urea in the formation of atmospheric secondary nitrogen contaminants and aerosols.
AbstractThe effects of urea on the hydrolysis reaction 2NO2 + mH2O (m = 1–3) have been investigated by theoretical calculations. The energy barrier (−2.67 kcal mol−1) of the urea-promoted reaction is lower than the naked reaction by 14.37 kcal mol−1. Urea also has a better catalytic effect on the reaction than methylamine and ammonia. Urea acts as a catalyst and proton transfer medium in this process, and the produced HONO may serve as a source of atmospheric nitrous acid. In addition, the subsequent reactions include clusters of nitrite, urea, and nitric acid. Then urea nitrate (UN), which is a typical HNO3 aerosol, can be formed in the subsequent reactions. The production of the acid-base complex (UN-2) is more favourable with an energy barrier of 0.10 kcal mol−1, which is 3.88 kcal mol−1 lower than that of the zwitterions NH2CONH3+NO3− (UN-1). The formation of zwitterions and the hydrolysis reaction are affected by humidity. The multi water-promoted hydrolysis reactions exhibit better thermodynamic stability when the humidity is increased. The extra water molecules act as solvent molecules to reduce the energy barrier. The natural bond orbital (NBO) analysis is employed to describe the donor-acceptor interactions of the complexes. The hydrogen bond interaction between the urea carbonyl and nitric acid of UN-2 is the strongest. The potential distribution maps of the urea nitrate and hydrate are examined, and the result shows that they tend to form zwitterions.
Upstream passage of adult sea trout (Salmo trutta) at a low-head weir with an Archimedean screw hydropower turbine and co-located fish pass
Authors: Dodd Jamie R. , Bolland Jonathan D. , Hateley Jon , Cowx Ian G. , Walton Sam E. , Cattaneo Marco E. G. V. , Noble Richard A. A.
Published: September 2018

The exploitation of riverine systems for renewable energy has resulted in large numbers of small-scale hydropower schemes on low-head weirs. Although considered a clean and ‘green’ energy source in terms of emissions, hydropower can affect upstream migrating species by diverting flow away from viable routes over the impoundment and attract fish towards the turbine outfall. In an attempt to reduce this negative effect, hydropower outfalls with co-located fish-passage entrances are recommended, utilising turbine flows to attract fish towards the fish pass. The present study used acoustic telemetry to understand the performance of a co-located Larinier fish pass at a low-head hydropower scheme at a weir on the tidal Yorkshire Esk, England. The majority of the sea trout (anadromous Salmo trutta L.) individuals that approached the impediment were attracted to the hydropower and the co-located fish pass. Fish ascended through the pass under a wide range of river flows, tide heights, downstream river levels and hydropower flows, and there was no evidence that the hydropower operation affected fish-pass ascent. The information presented is urgently required to inform management decisions on the operation of hydropower schemes during the migratory period of salmonid fish, and help determine best-practice designs and operation at these facilities.
Autonomous conformational regulation of β
3
integrin and the conformation-dependent property of HPA-1a alloantibodies
Authors: Thinn Aye Myat Myat , Wang Zhengli , Zhou Dongwen , Zhao Yan , Curtis Brian R. , Zhu Jieqing
Published: September 2018

Integrin α/β heterodimer adopts a compact bent conformation in the resting state, and upon activation undergoes a large-scale conformational rearrangement. During the inside-out activation, signals impinging on the cytoplasmic tail of β subunit induce the α/β separation at the transmembrane and cytoplasmic domains, leading to the extended conformation of the ectodomain with the separated leg and the opening headpiece that is required for the high-affinity ligand binding. It remains enigmatic which integrin subunit drives the bent-to-extended conformational rearrangement in the inside-out activation. The β
3
integrins, including α
IIb
β
3
and α
V
β
3
, are the prototypes for understanding integrin structural regulation. The Leu33Pro polymorphism located at the β
3
PSI domain defines the human platelet-specific alloantigen (HPA) 1a/b, which provokes the alloimmune response leading to clinically important bleeding disorders. Some, but not all, anti–HPA-1a alloantibodies can distinguish the α
IIb
β
3
from α
V
β
3
and affect their functions with unknown mechanisms. Here we designed a single-chain β
3
subunit that mimics a separation of α/β heterodimer on inside-out activation. Our crystallographic and functional studies show that the single-chain β
3
integrin folds into a bent conformation in solution but spontaneously extends on the cell surface. This demonstrates that the β
3
subunit autonomously drives the membrane-dependent conformational rearrangement during integrin activation. Using the single-chain β
3
integrin, we identified the conformation-dependent property of anti–HPA-1a alloantibodies, which enables them to differently recognize the β
3
in the bent state vs. the extended state and in the complex with α
IIb
vs. α
V
. This study provides deeper understandings of integrin conformational activation on the cell surface.
Cell-to-cell bacterial interactions promoted by drier conditions on soil surfaces
Authors: Tecon Robin , Ebrahimi Ali , Kleyer Hannah , Erev Levi Shai , Or Dani
Published: September 2018

Bacterial cell-to-cell interactions are in the core of evolutionary and ecological processes in soil and other environments. Under most conditions, natural soils are unsaturated where the fragmented aqueous habitats and thin liquid films confine bacterial cells within small volumes and close proximity for prolonged periods. We report effects of a range of hydration conditions on bacterial cell-level interactions that are marked by plasmid transfer between donor and recipient cells within populations of the soil bacterium
Pseudomonas putida
. Using hydration-controlled sand microcosms, we demonstrate that the frequency of cell-to-cell contacts under prescribed hydration increases with lowering water potential values (i.e., under drier conditions where the aqueous phase shrinks and fragments). These observations were supported using a mechanistic individual-based model for linking macroscopic soil water potential to microscopic distribution of liquid phase and explicit bacterial cell interactions in a simplified porous medium. Model results are in good agreement with observations and inspire confidence in the underlying mechanisms. The study highlights important physical factors that control short-range bacterial cell interactions in soil and on surfaces, specifically, the central role of the aqueous phase in mediating bacterial interactions and conditions that promote genetic information transfer in support of soil microbial diversity.
Elevated A20 promotes TNF-induced and RIPK1-dependent intestinal epithelial cell death
Authors: Garcia-Carbonell Ricard , Wong Jerry , Kim Ju Youn , Close Lisa Abernathy , Boland Brigid S. , Wong Thomas L. , Harris Philip A. , Ho Samuel B. , Das Soumita , Ernst Peter B. , Sasik Roman , Sandborn William J. , Bertin John , Gough Pete J. , Chang John T. , Kelliher Michelle , Boone David , Guma Monica , Karin Michael
Published: September 2018

Significance

Excessive apoptosis is detected in the intestinal epithelium of patients with inflammatory bowel disease (IBD), where it is frequently TNF-dependent. We show that A20, a protein implicated in negative regulation of NF-κB, is expressed in intestinal epithelial cells (IECs) from patients with IBD in areas that exhibit apoptosis. Transgenic mice that overexpress A20 in IECs are highly susceptible to TNF-induced cell death. In these mice, A20 potentiates TNF-induced mucosal erosion and RIPK1-dependent IEC apoptosis through Ripoptosome/RIPK1 activation. A20-enhanced IEC damage and intestinal inflammation can be prevented by RIPK1 inhibitors, suggesting a new approach to IBD treatment.