bluuebunny/crossref_metadata_2025 huggingface dataset:
Reflektionen zur unvollständigen Dokumentation von Missbrauch
und Vernachlässigung in der Kindheit bei stationären
psychiatrischen Behandlungen von Erwachsenen
Authors: Neumann Eva , Juckel Georg , Haußleiter Ida Sibylle
Published: December 2021

Es ist gut belegt, dass Kindesmisshandlung mit der Entstehung und
Aufrechterhaltung von psychischen Erkrankungen im Erwachsenenalter
zusammenhängt. Das Ziel der vorliegenden Arbeit ist es, darüber
zu reflektieren, ob diese negativen Erfahrungen in der psychiatrischen Praxis
angemessen berücksichtigt werden. Die medizinischen Akten von 3680
stationär behandelten erwachsenen Patienten einer psychiatrischen Klinik
wurden analysiert in Bezug auf Einträge, die sich auf Erfahrungen von
Missbrauch und Vernachlässigung in der Kindheit beziehen. Patienten mit
der Diagnose einer Störung durch psychotrope Substanzen, einer
schizophrenen oder einer affektiven Störung wurden in dieser Arbeit
betrachtet. Einträge, die sich auf traumatische Erfahrungen beziehen,
wurden nach der Unterteilung in emotionalen, körperlichen und sexuellen
Missbrauch sowie emotionale und körperliche Vernachlässigung
klassifiziert. Nur in 6% der Fälle fanden sich Hinweise auf
traumatische Erfahrungen in der Kindheit in den Akten. Die drei Arten von
Missbrauch wurden am häufigsten dokumentiert, während sich nur
wenige Einträge zu emotionaler und körperlicher
Vernachlässigung fanden. Frühere Arbeiten legen allerdings nahe,
dass die Häufigkeit von Missbrauch und Vernachlässigung in der
Kindheit bei psychiatrischen Patienten deutlich höher ist als die
Häufigkeit, die hier anhand der Akteneiträge ermittelt wurde.
Diese negativen Kindheitserfahrungen wurden in den psychiatrischen Behandlungen
offenbar wenig beachtet. Wegen ihrer Relevanz für das
Verständnis psychischer Störungen empfehlen wir, sie in
strukturierter Weise zu erfassen, entweder mit standardisierten
Fragebögen oder mit Screening-Fragen in der Eingangsuntersuchung.
Sekundäre Nutzung von hausärztlichen Routinedaten ist
machbar – Bericht vom RADAR Projekt
Authors: Hauswaldt Johannes , Bahls Thomas , Blumentritt Arne , Demmer Iris , Drepper Johannes , Groh Roland , Heinemann Stephanie , Hoffmann Wolfgang , Kempter Valérie , Pung Johannes , Rienhoff Otto , Schlegelmilch Falk , Wieder Philipp , Yahyapour Ramin , Hummers Eva
Published: December 2021

Ziel der Studie „Real world“-Daten aus der ambulanten
Gesundheitsversorgung sind in Deutschland nur schwer systematisch und
longitudinal zu erlangen. Unsere Vision ist eine permanente Datenablage mit
repräsentativen, de-identifizierten Patienten- und Versorgungsdaten,
längsschnittlich, fortwährend aktualisiert und von verschiedenen
Versorgern, mit der Möglichkeit zur Verknüpfung mit weiteren
Daten, etwa aus Patientenbefragungen oder biologischer Forschung,
zugänglich für andere Forscher. Wir berichten methodische
Vorgehensweisen und Ergebnisse aus dem RADAR Projekt.Methodik Untersuchung des
Rechtsrahmens, Entwicklung prototypischer technischer Abläufe und
Lösungen, mit Machbarkeitsstudie zur Evaluation von technischer und
inhaltlicher Funktionalität sowie Eignung für Fragestellungen
der Versorgungsforschung.Ergebnisse Ab 2016 entwickelte ein
interdisziplinäres Wissenschaftlerteam ein Datenschutzkonzept
für Exporte von Versorgungsdaten aus elektronischen
Praxisverwaltungssystemen. Eine technische und organisatorische
Forschungsinfrastruktur im ambulanten Sektor wurden entwickelt und im
Anwendungsfall „Orale Antikoagulation“ (OAK) umgesetzt. In 7
niedersächsischen Hausarztpraxen wurden 100 Patienten gewonnen und nach
informierter Einwilligung ihre ausgewählten Behandlungsdaten, reduziert
auf 40 relevante Datenfelder, über die
Behandlungsdatentransfer-Schnittstelle extrahiert, unmittelbar vor Ort in
identifizierende bzw. medizinische Daten getrennt und verschlüsselt zur
Treuhandstelle (THS) bzw. an den Datenhalter übertragen. 75 Patienten,
die die Einschlusskriterien erfüllten (mind. 1 Jahr Behandlung mit OAK),
erhielten einen Lebensqualitäts-Fragebogen über die THS per
Post. Von 66 Rücksendungen wurden 63 Fragebogenergebnisse mit den
Behandlungsdaten in der Datenablage verknüpft.Schlussfolgerung Die
rechtskonforme Machbarkeit der Gewinnung von pseudonymisierten
hausärztlichen Routinedaten mit expliziter informierter
Patienteneinwilligung und deren wissenschaftliche Nutzung einschließlich
Re-Kontaktierung und Einbindung von Fragebogendaten konnte nachgewiesen werden.
Die Schutzkonzepte Privacy by design und Datenminimierung (Artikel 25 mit
Erwägungsgrund 78 DSGVO) wurden systematisch in das RADAR Projekt
integriert und begründen wesentlich, dass der Machbarkeitsnachweis
rechtskonformer Primärdatengewinnung und sekundärer Nutzung
für Forschungszwecke gelang. Eine Nutzung hinreichend anonymisierter,
aber noch sinnvoller hausärztlicher Gesundheitsdaten ohne individuelle
Einwilligung ist im bestehenden Rechtsrahmen in Deutschland schwerlich
umsetzbar.
The Contributions of Model Studies for Fundamental Understanding of Polymer Mechanochemistry
Authors: O’Neill Robert T. , Boulatov Roman
Published: December 2021

The exciting field of polymer mechanochemistry has made great empirical progress in discovering reactions in which a stretching force accelerates scission of strained bonds using single molecule force spectroscopy and ultrasonication experiments. Understanding why these reactions happen, i.e., the fundamental physical processes that govern coupling of macroscopic motion to chemical reactions, as well as discovering other patterns of mechanochemical reactivity require complementary techniques, which permit a much more detailed characterization of reaction mechanisms and the distribution of force in reacting molecules than are achievable in SMFS or ultrasonication. A molecular force probe allows the specific pattern of molecular strain that is responsible for localized reactions in stretched polymers to be reproduced accurately in non-polymeric substrates using molecular design rather than atomistically intractable collective motions of millions of atoms comprising macroscopic motion. In this review, we highlight the necessary features of a useful molecular force probe and describe their realization in stiff stilbene macrocycles. We describe how studying these macrocycles using classical tools of physical organic chemistry has allowed detailed characterizations of mechanochemical reactivity, explain some of the most unexpected insights enabled by these probes, and speculate how they may guide the next stage of mechanochemistry.
Evidence-Based Guidelines for Acute Stabilization and Management of Neonates with Persistent Pulmonary Hypertension of the Newborn
Authors: Ball Molly K. , Seabrook Ruth B. , Bonachea Elizabeth M. , Chen Bernadette , Fathi Omid , Nankervis Craig A. , Osman Ahmed , Schlegel Amy B. , Magers Jacqueline , Kulpa Taylor , Sharpin Paula , Snyder Mary Lindsay , Gajarski Robert J. , Nandi Deipanjan , Backes Carl H.
Published: December 2021

Persistent pulmonary hypertension of the newborn, or PPHN, represents a challenging condition associated with high morbidity and mortality. Management is complicated by complex pathophysiology and limited neonatal specific evidence-based literature, leading to a lack of universal contemporary clinical guidelines for the care of these patients. To address this need and to provide consistent high-quality clinical care for this challenging population in our neonatal intensive care unit, we sought to develop a comprehensive clinical guideline for the acute stabilization and management of neonates with PPHN. Utilizing cross-disciplinary expertise and incorporating an extensive literature search to guide best practice, we present an approachable, pragmatic, and clinically relevant guide for the bedside management of acute PPHN.

Key Points
Dentistry and Intensive Care Unit: A Brief Report
Authors: Bannwart Lisiane Cristina , de Moraes Melo Neto Clóvis Lamartine , dos Santos Daniela Micheline , Moreno André Luiz de Melo , Pesqueira Aldiéris Alves , Goiato Marcelo Coelho , de Magalhães Bertoz André Pinheiro
Published: December 2021

Objective The aim of this study is to verify whether removable dentures of patients admitted to an intensive care unit (ICU) are niches of microorganisms that can cause pathologies (Staphylococcus aureus, Candida spp., and enterobacteria).

Materials and Methods Fifteen patients who were denture wearers (removable partial denture and complete denture) were included in this study. Patients must wear their dentures daily, and these dentures must have acrylic parts. Microbial biofilm was collected from the acrylic part of one denture of each patient. Then, the biofilm was seeded on different culture media: Sabouraud agar, blood agar, MacConkey agar, and mannitol salt agar. In this study, biochemical evaluations of microorganisms were performed.

Statistical analysis The percentage of dentures with the microorganism identified by each culture medium was calculated.

Results In total, 100% of the dentures were positive for Staphylococcus spp. (blood agar) and Candida spp. (Sabouraud agar); 33.3% of the dentures were positive for S. aureus (Mannitol salt agar); and 13.3% of the dentures were positive for Shigella spp. (MacConkey agar).

Conclusion Removable dentures of patients (removable partial dentures and complete dentures) admitted to an ICU are niches of microorganisms that can cause pathologies.
Nerve-Sparing Robotic Radical Hysterectomy for the Beginner in Robotic Surgery
Authors: Hiramatsu Yuji
Published: December 2021

Robotic surgery is considered to be the optimal means of performing nerve-sparing radical hysterectomy (RH) because this procedure requires very precise surgery. Nerve-sparing RH has become increasingly popular in Japan. However, with open surgery the operating field is only visible to the surgeon performing this delicate procedure, which makes it difficult to educate trainee assistants. However, robotic surgery provides an expanded operation field that is visible to the surgeon and assistants, which makes it suitable for teaching purposes. To perform this procedure, it is necessary to become proficient in RH by laparotomy and then to become familiar with the characteristics of robotic surgery. In shifting from laparotomy to robotic surgery, we have found that experience with open surgery does not fully prepare surgeons for the new experiences and discoveries associated with robotic surgery, which may initially be problematic. We here provide clear instructions for the procedure with notes concerning particular potentially problematic aspects.
Association between Gastric Cancer with Behavioral and Dietary Factors: A Hospital Based Case-Control Study in South Asia
Authors: Shahi Arun , Koyyala Venkata Pradeep Babu , Rathaur Ela Singh , Biddut Md. Assaduzaman , Hossain Anwor , Hasan Md. Kamrul , Alam Jahangir , Hossain Tanzina , Khatun Nazrina
Published: December 2021

Background Gastric cancer (GC) is one of the most common malignancies and a leading cause of mortality and morbidity worldwide. It is the fourth leading cancer in Bangladesh. Identification of risk factors, effective prevention, and early diagnosis are the most important interventions against GC.

Objectives To find an association of dietary and behavioral factors in the development of GC among the Bangladeshi population.

Methods This case–control study was conducted from January 2017 to December 2018 at the National Institute of Cancer Research and Hospital, Dhaka, Bangladesh. A total of 178 patients were studied (89 case and 89 controls). Data were collected via face-to-face interview using a standard structured questionnaire, posing questions about socio-demographic, behavioral and dietary habits, and clinical factors. A binary logistic regression method was used to calculate the odds ratio (OR).

Results Among 178 patients, the age group ranged from 30 to 80 years and most patients were between 51 to 60 years. The results showed that regular consumption of red meat, duration of smoking, smokeless tobacco, fast food and fatty food, and family history of any type of cancer were directly associated with the risk of GC. On the contrary, a habit of regular walking and playing sports has an inverse association with GC. Adjusted OR shows regular consumption of red meat has 2.6 times more risk (OR = 2.661) of developing GC compared with irregular meat consumption, and a person with a history of Helicobacter pylori infection is 53% (OR = 7.263; 95% confidence interval: 3.614–14.597) more likely to develop cancer. In contrast, people who were doing exercise regularly for at least 30 minutes/day are 62.7% (OR = 0.373) less likely to develop GC than those who did not.

Conclusion The study showed an association of some dietary and behavioral factor in the development of GC. However, more research in this field is required to understand the etiology, for the development of suitable screening test, for demarcation of high-risk population, and to develop and evaluate the effectiveness of primary prevention programs.
The Effect of “Off Hours” on Maternal and Perinatal Outcomes in a Diverse U.S. Cohort
Authors: Arslan Erol , Einerson Brett D. , Zhang Jingwen , Zhang Jun , Branch D. Ware
Published: December 2021

Objective This study aimed to evaluate the “off-hour effect” on maternal and neonatal adverse events in a large cohort representing U.S. population.

Study Design A secondary analysis of the Consortium on Safe Labor (CSL) dataset with 208,695 women and 229,385 deliveries was performed. The study included the deliveries of ≥23 gestational weeks from 19 hospitals in the United States from 2002 to 2008. Babies with congenital anomalies were excluded from neonatal outcomes. We compared maternal and neonatal outcomes of patients delivered during weekdays versus off hours (nights and weekends). The primary outcomes of the study were composite maternal and composite neonatal adverse events. The secondary outcomes were delivery type and individual maternal and neonatal adverse events including maternal death and perinatal mortality rate. Associations between off hours and all the outcomes were analyzed in bivariable and multivariable analyses. The same analyses were performed in strata by indication for admission (spontaneous labor or induction of labor).

Results Composite maternal adverse events (6.19 vs. 6.06%, p = 0.41) and maternal death (0.01 vs. 0.01%, p = 0.19) were not significantly different between off hours and weekday groups. In contrast, composite neonatal adverse events (6.91 vs. 5.84%, p < 0.001) and perinatal mortality rate (1.03 vs. 0.77%, p < 0.001) were higher in the off-hour group. After adjusting for confounding variables, only the composite neonatal outcome continued to be associated with off hours (adjusted odds ratio [aOR] = 1.10, 95% confidence interval [CI]: 1.04–1.16). Stratified analyses showed that the off-hour effect for the neonatal composite outcome was not present in those presenting in spontaneous labor (6.1 vs. 5.9%, p = 0.40).

Conclusion Off-hour delivery was not associated with severe maternal morbidity and was only modestly associated with severe neonatal morbidity. This association was observed in women undergoing induction, not in those presenting in spontaneous labor. These data draw into question the existence of a clinically meaningful and correctable “off-hour effect” in obstetrics.

Key Points
Tissue model shows cells grown at the top of biodegradable scaffold consume nutrients first
Authors: Piccone Ashley
Published: December 2021

Hungry cells eat in a staggered manner, impacting overall tissue growth
Exploring liquid plasma jets using short laser pulses
Authors: Thompson Avery
Published: December 2021

Method probes the optical properties of laser-induced liquid plasmas using extremely short laser pulses.
On the use of field programmable gate arrays in light detection and ranging systems
Authors: Leoni A. , Esposito P. , Stornelli V. , Saggio G. , Ferri G.
Published: December 2021

This work aims to provide details on the latest technological developments regarding LiDAR (Light Imaging Detection And Ranging) systems, with particular reference to the techniques, architectures, and methodologies partially or entirely implemented by means of the FPGA (Field Programmable Gate Array) environment. Currently, LiDAR technology is considered of great interest as it is widely employed in a variety of application fields, such as automotive, seismology, archaeology, metrology, and military. For this reason, the required performances are gradually increasing, which leads to complex and stringent solutions. The growth in LiDAR systems’ complexity suggests the use of high-end general-purpose computing units such as central processing units to perform very complex tasks and FPGAs to perform multiple tasks in real-time through the implementation of dedicated computational blocks. The latter, in recent architectures, are therefore used for the execution of specific tasks that require high computational speed and system flexibility. This paper reports some case studies recently applied in the LiDAR field, with the aim of illustrating the role of FPGA technology and its benefits.
Simultaneous high-resolution x-ray backlighting and self-emission imaging for laser-produced plasma diagnostics using a two-energy multilayer Kirkpatrick–Baez microscope
Authors: Yi S. Z. , Dong J. Q. , Jiang L. , Huang Q. S. , Guo E. F. , Z. S. Wang
Published: December 2021

A simultaneous high-resolution x-ray backlighting and self-emission imaging method for laser-produced plasma diagnostics is developed in which two Kirkpatrick–Baez imaging channels for high-energy and low-energy diagnostics are constructed using a combination of multilayer mirrors in near-coaxial form. By using a streak or framing camera placed on the image plane, both backlit and self-emission images of a laser-produced plasma with high spatial and temporal resolution can be obtained simultaneously in a single shot. This paper describes the details of the method with regard to its optical and multilayer design, assembly, and alignment method. In addition, x-ray imaging results with a spatial resolution better than 5 µm in the laboratory and experimental results with imploding capsules in the SG-III prototype laser facility are presented.
Diamond anvil cell with double coaxial chambers
Authors: Jiang Dawei , Gao Yang , Cao Min , Jia Caihong , Zhao Xingxing , Han Yonghao , Gao Chunxiao
Published: December 2021

In general, pressure calibration in diamond anvil cells (DACs) has been achieved by mixing pressure calibration materials (PCMs) with the sample inside the pressure chamber. However, the chemical reactions between the sample and PCMs are sometimes unavoidable at extreme conditions, such as high pressure and high temperature. These undesired reactions will cause pollution, induce changes in physical properties or phase transformations of PCMs, and result in tremendous error of pressure calibration. In this paper, we report a new design of DAC with double coaxial pressure chambers, sample and PCM chambers, to resolve the challenge by isolating the PCM from the sample. Our test results show that the pressure of the two chambers presents interesting relations with the anvil setup. When the geometric parameters of two anvil sets are the same and the difference of chamber diameters is within a certain range (i.e., below 10 µm), the pressure correlation between the two chambers shows little correlation with the pressure transmitting medium before and after its solidification at both room temperature and high temperatures within the experimental condition range (well below 20 GPa and 634 K). In this case, the pressure of the sample chamber can be well calibrated by the pressure of the PCM chamber. This new DAC setup is thus proved to be effective in calibrating the sample pressure below certain conditions while avoiding undesired sample pollution and pressure induced property changes in PCMs under high pressure and high temperature conditions compared with single-chamber DACs.
A new form of general soliton solutions and multiple zeros solutions for a higher-order Kaup–Newell equation
Authors: Zhu Jin-Yan , Chen Yong
Published: December 2021

Due to the fact that the higher-order Kaup–Newell (KN) system has more complex and diverse solutions than the classical second-order flow KN system, the research on it has attracted much attention. In this paper, we consider a higher-order KN equation with third-order dispersion and fifth-order nonlinearity. Based on the theory of the inverse scattering, the matrix Riemann–Hilbert problem is established. Through the dressing method, the solution matrix with simple zeros without reflection is constructed. In particular, a new form of solution is given which is more direct and simpler than previous methods. In addition, through the determinant solution matrix, the vivid diagrams and dynamic analysis of single-soliton solution and two-soliton solution are given in detail. Finally, by using the technique of limit, we construct the general solution matrix in the case of multiple zeros, and the examples of solutions for the cases of double zeros, triple zeros, single–double zeros, and double–double zeros are especially shown.
Kinetics of stepwise nitrogen adsorption by size-selected iron cluster cations: Evidence for size-dependent nitrogen phobia
Authors: Straßner Annika , Klein Matthias P. , Fries Daniela V. , Wiehn Christopher , Huber Maximilian E. , Mohrbach Jennifer , Dillinger Sebastian , Spelsberg Dirk , Armentrout P. B. , Niedner-Schatteburg Gereon
Published: December 2021

We present a study of stepwise cryogenic N2 adsorption on size-selected Fen+ (n = 8–20) clusters within a hexapole collision cell held at T = 21–28 K. The stoichiometries of the observed adsorption limits and the kinetic fits of stepwise N2 uptake reveal cluster size-dependent variations that characterize four structural regions. Exploratory density functional theory studies support tentative structural assignment in terms of icosahedral, hexagonal antiprismatic, and closely packed structural motifs. There are three particularly noteworthy cases, Fe13+ with a peculiar metastable adsorption limit, Fe17+ with unprecedented nitrogen phobia (inefficient N2 adsorption), and Fe18+ with an isomeric mixture that undergoes relaxation upon considerable N2 uptake.
Strong spin–phonon coupling in Gd-filled nanotubes
Authors: Sodisetti V. R. , Ncube S. , Coleman C. , Erasmus R. M. , Flahaut E. , Bhattacharyya S.
Published: December 2021

To develop one-dimensional spintronic devices, we synthesize Gd-filled double-walled carbon nanotubes where the long spin-coherence time of a paramagnetic gadolinium (Gd3+) ion and the discrete phonon modes of a carbon nanotube can be combined. Here, we report Raman observation of spin–phonon coupling in the Gd-filled double-walled nanotubes by analyzing the low-temperature dependence of the dominant phonon modes (G-band). A G-band (ωGext+andωGint+) phonon frequency hardening is observed below a critical temperature of TC ∼ 110 K coinciding with the onset temperature of superparamagnetic behavior confirmed through magnetization studies. This anomalous behavior is ascribed to phonon renormalization induced by spin–phonon coupling interaction. The estimated spin–phonon coupling constant values are 12.2 and 5.0 cm−1 for Gext+ and Gint+ phonon modes, respectively, analyzed by comparing the phonon frequency variation (Δω) to magnetization as a function of temperature. Realizing a spin–phonon coupling (three times higher than for other multiferroic compounds) interface and modulating it in a one-dimensional system have potential benefit when designing effective molecular qubits.
Numerical study on the effects of modulated ventilation on unsteady cavity dynamics and noise patterns
Authors: Sun Tiezhi , Ding Yanyi , Huang Huakun , Xie Bohan , Zhang Guiyong
Published: December 2021

Supercavitating flow is accompanied by significant unsteady characteristics, and it is therefore very important to find methods to control this multiphase flow phenomenon. Ventilation is an important method for creating supercavitation and it affects the evolution, load, and noise characteristics. In this paper, cavity flows with and without modulated ventilation (i.e., the imposition of a sinusoidal component on the ventilation rate) are investigated using computational fluid dynamics techniques incorporating large eddy simulation, coupled with the Ffowcs Williams–Hawkings (FW–H) method. The effects of modulated ventilation on cavity shedding, vortex structure, and the noise characteristics of the cavity are compared and analyzed. The results show that modulated ventilation can change the shedding period of the ventilated cavity and can slightly improve its lift and drag performance. It can also promote the formation and growth of hairpin vortices and impose a periodicity on the evolution of the vortex structure. Furthermore, although modulated ventilation cavitation enhances pressure fluctuations near the vent and increases the self-noise of ventilation, it has little impact on far-field noise while reducing the turbulence of the far field, which decreases the total sound pressure level in the wake of the cavitator.
Non-neutral plasma manipulation techniques in development of a high-capacity positron trap
Authors: Singer M. , König S. , Stoneking M. R. , Steinbrunner P. , Danielson J. R. , Schweikhard L. , Pedersen T. Sunn
Published: December 2021

Preliminary experiments have been performed toward the development of a multi-cell Penning–Malmberg trap for the storage of large numbers of positrons (≥1010 e+). We introduce the master-cell test trap and the diagnostic tools for first experiments with electrons. The usage of a phosphor screen to measure the z-integrated plasma distribution and the number of confined particles is demonstrated, as well as the trap alignment to the magnetic field (B = 3.1 T) using the m = 1 diocotron mode. The plasma parameters and expansion are described along with the autoresonant excitation of the diocotron mode using rotating dipole fields and frequency chirped sinusoidal drive signals. We analyze the reproducibility of the excitation and use these findings to settle on the path for the next generation multi-cell test device.
Direct emission of broadband terahertz cylindrical vector Bessel beam
Authors: Feng Xi , Wang Qingwei , Lu Yongchang , Xu Quan , Zhang Xueqian , Niu Li , Chen Xieyu , Li Quan , Han Jiaguang , Zhang Weili
Published: December 2021

As one kind of special beams, a terahertz (THz) cylindrical vector Bessel beam processes centrosymmetric polarization distribution and nondiffractive propagation properties. Such a vector Bessel beam is potential in various practical applications ranging from THz communication and electron acceleration to sensing and imaging. Here, we propose and experimentally demonstrate a method to directly emit a broadband THz cylindrical vector Bessel (CVB) beam using nonlinear effects. By photo-exciting an indium tin oxide film coated axicon with a circularly polarized femtosecond laser pulse, a high-quality CVB beam is obtained in a broadband THz frequency range. The proposed method is universal and low-cost, opening a simple avenue for the emission of broadband THz specialty beams.
Deformable hard particles confined in a disordered porous matrix
Authors: Stadik Alexander , Kahl Gerhard
Published: December 2021

With suitably designed Monte Carlo simulations, we have investigated the properties of mobile, impenetrable, yet deformable particles that are immersed into a porous matrix, the latter one realized by a frozen configuration of spherical particles. By virtue of a model put forward by Batista and Miller [Phys. Rev. Lett. 105, 088305 (2010)], the fluid particles can change in their surroundings, formed by other fluid particles or the matrix particles, their shape within the class of ellipsoids of revolution; such a change in shape is related to a change in energy, which is fed into suitably defined selection rules in the deformation “moves” of the Monte Carlo simulations. This concept represents a simple yet powerful model of realistic, deformable molecules with complex internal structures (such as dendrimers or polymers). For the evaluation of the properties of the system, we have used the well-known quenched-annealed protocol (with its characteristic double average prescription) and have analyzed the simulation data in terms of static properties (the radial distribution function and aspect ratio distribution of the ellipsoids) and dynamic features (notably the mean squared displacement). Our data provide evidence that the degree of deformability of the fluid particles has a distinct impact on the aforementioned properties of the system.
Methods for neutron diffraction studies on hydride superconductors and other metal hydrides
Authors: Haberl Bianca , Donnelly Mary-Ellen , Molaison Jamie J. , Guthrie Malcolm , Boehler Reinhard
Published: December 2021

High-pressure neutron diffraction is an extremely useful technique in the quest for making and understanding novel hydride superconductors. Neutron diffraction can be used to directly determine elemental stoichiometries and atomic positions of many light elements such as hydrogen or deuterium, even in the presence of heavy elements such as rare-earth metals. Here, we report on the current status and ongoing developments on high-pressure neutron diffraction for hydride superconductors and other metal hydrides with a special focus on current advancements at the Spallation Neutrons and Pressure (SNAP) beamline of the Spallation Neutron Source at Oak Ridge National Laboratory. For broader context, an overview of high-pressure neutron diffractometers and pressure cells is included together with insight into critical sample considerations. There, attention is given to the requirements for powdered hydride samples and the need for deuterium rather than hydrogen. Additionally, the advantages of angular access and data representation as possible at SNAP are described. We demonstrate the current capability for high-pressure neutron diffraction on two different samples created via hydrogen gas loading, specifically pure deuterium and nickel-deuteride. The deuterium example highlights the usefulness of adding sample materials that facilitate the formation of a good powder while the nickel-deuteride example demonstrates that atomic deuterium positions and stoichiometry can be directly determined. Both examples highlight the importance of large scattering apertures. These enable investigation of the data resolved by scattering angle that is needed to identify parasitic peaks and background features. Finally, future directions beyond current high-pressure neutron powder diffraction are also discussed.
Crown rupture during droplet impact on a dry smooth surface at increased pressure
Authors: Xu Zhigang , Wang Longlong , Wang Tianyou , Che Zhizhao
Published: December 2021

The impact of droplets at increased environmental pressure is important in many industrial applications. Previous studies mainly considered the impact process at standard or reduced environmental pressure, and the effect of high environmental pressure is unclear. In this study, we experimentally investigate the impact of ethanol droplets on dry smooth surfaces at increased environmental pressure. The effects of the environmental pressure on the splashing and rupture of the crown during the impact process are analyzed. The results show that surrounding gas with high environmental pressure can lead to the splashing of the crown in a “thread rupture” mode and the sizes of the secondary droplets from the rim of the liquid crown increase with the environmental pressure. The threshold for the transition from spreading to splashing during the impact process is obtained based on the theory of aerodynamics analysis of the lamella. At increased environmental pressure, the threshold speed of the impact decreases with increasing the environmental pressure because the wedge of the lamella is prevented from moving forward and is driven to detach from the substrate by the air ahead, which has a higher density due to the higher environmental pressure.
Nonlinear stability of regular vortex polygons in a Bose–Einstein condensate
Authors: Artemova Elizaveta , Kilin Alexander
Published: December 2021

The problem of stability of rotating regular vortex N-gons (Thomson's configurations) in a Bose–Einstein condensate in a harmonic trap is considered. A reduction procedure on the level set of the momentum integral is proposed. The dependence of the velocity of rotation ω of vortex polygon about the center of the trap is obtained as a function of the number of vortices N and the radius of the configuration, R. The analysis of the orbital linear and nonlinear stability of the motion of such configurations is carried out. For N ⩽ 6, regions of orbital stability of configurations in the parameter space are constructed. It is shown that vortex N-gons for N>6 are unstable for any parameters of the system. In this paper, we study the stability of rotating regular vortex N-gons in a Bose–Einstein condensate in a harmonic trap. The analysis of the orbital linear and nonlinear stability of motion is carried out. The dependence of the stability of regular vortex N-gons on the number of vortices N and the parameters of the system is given.
Numerical simulation of the interaction between double cathode spot craters in vacuum arc
Authors: Li Jiagang , Wang Lijun , Gao Hexiao , Zhang Xiao , Zhang Runming
Published: December 2021

In this paper, a numerical simulation on the interaction between the double cathode spot craters in the vacuum arc is carried out. By establishing a double-cathode spot ablation model, the crater development process when two spots coexist is simulated, and the formation mechanism of cathode spot groups is analyzed. The simulation results show that the two cathode spots appearing on the flat electrode would squeeze each other to form a liquid metal ridge, which changed the ablation morphology of the cathode spots. When the double-spot arc craters appear simultaneously, the metal ridge will be squeezed into a straight line, otherwise, when the spots appear one after another, the liquid metal ridge will shift toward the side of the spot that appears first. The relative experimental results are adopted to compare with the simulation results. By comparison, it is found that the morphology of the multi-spot crater in the experiment is in agreement with the simulation results.
Effects of nutrient depletion on tissue growth in a tissue engineering scaffold pore
Authors: Zong Zeshun , Li Xinyu , Sanaei Pejman
Published: December 2021

In a tissue engineering scaffold pore lined with cells, nutrient-rich culture medium flows through the scaffold and the cells proliferate. In this process, both environmental factors—such as flow rate and shear stress—as well as cell properties have significant effects on tissue growth. Recent studies have focused on the effects of scaffold pore geometry on tissue growth, while in this work, we focus on the nutrient depletion and consumption rate by the cells, which cause a change in the nutrient concentration of the feed and influence the growth of cells lined downstream. In this paper, our objectives are threefold: (i) design a mathematical model for the cell proliferation describing fluid dynamics, nutrient concentration, and tissue growth; (ii) solve the models and then simulate the tissue proliferation process; (iii) design a “reverse algorithm” to find the initial configuration of the scaffold with the knowledge of the desired property of the final tissue geometry. Our model reduces the numerical burdens and captures the experimental observations from the literature. In addition, it provides an efficient algorithm to simulate the cell proliferation and determine the design of a tissue engineering scaffold given a desired tissue profile outcome.
Toward Peltier-cooled mid-infrared HgCdTe lasers: Analyzing the temperature quenching of stimulated emission at ∼6 μm wavelength from HgCdTe quantum wells
Authors: Kudryavtsev K. E. , Rumyantsev V. V. , Utochkin V. V. , Fadeev M. A. , Aleshkin V. Ya. , Dubinov A. A. , Zholudev M. S. , Mikhailov N. N. , Dvoretskii S. A. , Remesnik V. G. , Teppe F. , Gavrilenko V. I. , Morozov S. V.
Published: December 2021

Despite the ultimate performance of the existing cascade lasers, simple interband emitters in the mid-infrared (IR) can still be of interest as a cheaper and widely tunable alternative for some applications. In this work, we show mid-infrared stimulated emission (SE) at 5–6 μm wavelength from an optically pumped mercury–cadmium–telluride quantum well (QW) heterostructures at temperatures up to 200 K. At lower temperatures, the SE threshold appears to be mostly determined by conventional eeh Auger recombination, while the contribution of alternative QW-specific ehh Auger processes is limited. At higher temperatures, we establish heating of the electron gas by pumping radiation as a primary factor responsible for the thermal quenching of the SE. Consequently, both pumping scheme and QW designs should be carefully revised to minimize carrier heating in order to realize near-to-mid-IR optical converters operating close to ambient temperature. We suggest using low-barrier QWs to minimize excessive heat introduced in the QW upon carrier capture and also to eliminate eeh Auger processes involving excited QW subbands. Thus, mid-infrared HgCdTe lasers are expected to reach operating temperatures readily attainable under thermoelectric cooling.
Features of surface physical quantities and temporal-spatial evolution of wall-normal enstrophy flux in wall-bounded flows
Authors: Chen Tao , Liu Tianshu , Wang Lian-Ping
Published: December 2021

This paper presents a concise derivation of the temporal-spatial evolution equation of the wall-normal enstrophy flux on a no-slip flat wall. Each contribution to the evolution is explicitly expressed using the two fundamental surface quantities: skin friction (or equivalently surface vorticity) and surface pressure which are coupled through the boundary enstrophy flux (BEF). The newly derived relation is then used to explore, in a preliminary manner, the physical features of surface quantities and their dynamical roles in wall-bounded laminar and turbulent flows. It is confirmed that the BEF usually changes its sign near the separation and attachment lines in the skin friction field. For the simulated incompressible turbulent channel flow at Reτ=180, violent variations of different terms in the derived formulation are observed in the regions below the strong wall-normal velocity events (SWNVEs) when compared to other common regions. Near the SWNVEs, the evolution of the wall-normal enstrophy flux is found to be dominated by the wall-normal diffusion of the vortex stretching term which is relatively weak or negligible for laminar flows. Combined with our previous research results, it is conjectured that the strong interaction between the quasi-streamwise vortex and the channel wall intensifies the temporal-spatial evolution of the wall-normal enstrophy flux on the wall, which accounts for the highly intermittent feature of the viscous sublayer.
Spatial evolution of magnetic reconnection diffusion region structures with distance from the X-line
Authors: Øieroset M. , Phan T. D. , Ergun R. , Ahmadi N. , Genestreti K. , Drake J. F. , Liu Y.-H. , Haggerty C. , Eastwood J. P. , Shay M. A. , Pyakurel P. S. , Haaland S. , Oka M. , Goodbred M. , Eriksson S. , Burch J. L. , Torbert R. B. , Khotyaintsev Y. , Russell C. T. , Strangeway R. J. , Gershman D. J. , Giles B. L.
Published: December 2021

We report Magnetospheric Multiscale four-spacecraft observations of a thin reconnecting current sheet with weakly asymmetric inflow conditions and a guide field of approximately twice the reconnecting magnetic field. The event was observed at the interface of interlinked magnetic field lines at the flank magnetopause when the maximum spacecraft separation was 370 km and the spacecraft covered ∼1.7 ion inertial lengths (di) in the reconnection outflow direction. The ion-scale spacecraft separation made it possible to observe the transition from electron-only super ion-Alfvénic outflow near the electron diffusion region (EDR) to the emergence of sub-Alfvénic ion outflow in the ion diffusion region (IDR). The EDR to IDR evolution over a distance less than 2 di also shows the transition from a near-linear reconnecting magnetic field reversal to a more bifurcated current sheet as well as significant decreases in the parallel electric field and dissipation. Both the ion and electron heating in this diffusion region event were similar to the previously reported heating in the far downstream exhausts. The dimensionless reconnection rate, obtained four different ways, was in the range of 0.13–0.27. This event reveals the rapid spatial evolution of the plasma and electromagnetic fields through the EDR to IDR transition region.
Sorted L1 regularization method for damage detection based on electrical impedance tomography
Authors: Fan A. Wenru , Cheng B. Yu
Published: December 2021

Carbon fiber reinforced polymers (CFRPs) are composite materials in which carbon provides strength and stiffness, whereas polymers provide cohesiveness and toughness. The electrical impedance of CFRP laminates is changed due to different kinds of damages. Electrical impedance tomography (EIT) has significant advantages such as non-intrusion, portability, low cost, and quick response and has widely been used as a nondestructive testing method. Therefore, EIT has great potential in structural health monitoring of CFRPs. Regularization can solve the ill-posed inverse problem of EIT. However, conventional regularization algorithms have their own limitations, such as over-smoothness of reconstructed edges and unstable solution caused by measurement noise. In addition, the anisotropic property of CFRPs also affects the image quality based on traditional methods. In this paper, the sorted L1-norm regularization is proposed. It promotes grouping highly correlated variables while encouraging sparsity by using more effective penalty terms. The sharp edges between different materials can be obtained, and the obtained solution is more stable. The image quality of different objects, especially the image quality of multi-targets, can be significantly improved with this new method. In addition, the sorted L1 norm can generate adaptive regularization parameters without empirical selection. The new regularization problem is solved by the alternating direction method of multipliers. Both experimental and simulation results demonstrate that the sorted L1 norm improves the quality of reconstructed images under various noise levels. The proposed method is comprehensively evaluated with three image quality criteria by numerical simulation quantitatively.
Scaling of global properties of fluctuating streamwise velocities in pipe flow: Impact of the viscous term
Authors: Basse Nils T.
Published: December 2021

We extend the procedure outlined in Basse [“Scaling of global properties of fluctuating and mean streamwise velocities in pipe flow: Characterization of a high Reynolds number transition region,” Phys. Fluids 33, 065127 (2021)] to study global, i.e., radially averaged, scaling of streamwise velocity fluctuations. A viscous term is added to the log-law scaling, which leads to the existence of a mathematical abstraction, which we call the “global peak.” The position and amplitude of this global peak are characterized and compared to the inner and outer peaks. A transition at a friction Reynolds number of order 10 000 is identified. Consequences for the global peak scaling, length scales, non-zero asymptotic viscosity, turbulent energy production/dissipation, and turbulence intensity scaling are appraised along with the impact of including an additional wake term.
Insights into the dynamics of wake flame in a freely falling droplet
Authors: Vadlamudi Gautham , Thirumalaikumaran S. K. , Basu Saptarshi
Published: December 2021

The combustion of a freely falling dodecane droplet has been studied experimentally in a droptower-like facility under ambient conditions. A unique ignition mechanism is used by igniting the droplet in pendant mode and releasing it to fall freely. This unveils a different type of droplet wake flame behavior which is explored in this study. Initially, the droplet flame transitions from fully enveloped to a wake flame configuration due to forward extinction. The wake flame has similar characteristics as a laminar lifted triple-flame. As the droplet accelerates, the flame stand-off increases continuously. The change in wake flame topology and intensity occurs in two different regimes corresponding to different droplet diameters. A new non-dimensional parameter has been derived to account for the local balance between buoyancy and momentum diffusion that alters the fuel availability. To explain the flame topological evolutions and transitions for different droplet diameters and Reynolds numbers, a theoretical formulation has been proposed based on the momentum diffusion from surrounding due to relative motion. Further, at very high Reynolds number, flame stretching or shedding regime occurs, causing momentary spikes in flame intensity due to the interaction with asymmetric vortex shedding induced by the Bernard–Von Karman instability. Interestingly, the flame shedding height follows the buoyant flickering scaling, even for the momentum-dominant droplet wake flame. Additionally, the circulation build-up mechanisms are shown to be responsible for the flame shedding events for droplet wake flame at high Reynolds number.
Coalescence of polymeric sessile drops on a partially wettable substrate
Authors: Varma Sarath Chandra , Saha Aniruddha , Kumar Aloke
Published: December 2021

Coalescence of sessile polymeric fluid drops on a partially wettable substrate exhibits a transition from the inertial to viscoelastic regime at concentration ratio c/c*∼1. Our findings unveil that the temporal evolution of the growing bridge height follows a power law behavior tb, such that the coefficient b continuously decreases from 2/3 in the inertial regime (c/c*<1) to an asymptotic value of 1/2 in the viscoelastic regime (c/c*>1). To account for fluid elasticity and characteristic timescale in the viscoelastic regime, a modified thin film equation under lubrication approximation has been proposed using the linear Phan–Thien–Tanner constitutive equation. The temporal evolution of the droplet has been evaluated by solving the modified one-dimensional thin film equation using a marching explicit scheme. The initial droplet shapes are obtained by resorting to energy minimization. Good agreement between numerical and experimental results is obtained.
Modulating internal transition kinetics of responsive macromolecules by collective crowding
Authors: Baul Upayan , Göth Nils , Bley Michael , Dzubiella Joachim
Published: December 2021

Packing and crowding are used in biology as mechanisms to (self-)regulate internal molecular or cellular processes based on collective signaling. Here, we study how the transition kinetics of an internal “switch” of responsive macromolecules is modified collectively by their spatial packing. We employ Brownian dynamics simulations of a model of Responsive Colloids, in which an explicit internal degree of freedom—here, the particle size—moving in a bimodal energy landscape self-consistently responds to the density fluctuations of the crowded environment. We demonstrate that populations and transition times for the two-state switching kinetics can be tuned over one order of magnitude by “self-crowding.” An exponential scaling law derived from a combination of Kramers’ and liquid state perturbation theory is in very good agreement with the simulations.