bluuebunny/crossref_metadata_2025 huggingface dataset:
Genetic Variability of the Paired Box Transcription Factor; PAX8 Gene: Guidance Towards Treatment Strategies in a Cohort of Congenital Hypothyroidism
Authors: El-Ella Sohier S. Abou , Khattab Essam Shawky A.E.H. , Beddah Rehab K. , Barseem Naglaa Fathy
Published: April 2021

The contribution of PAX8 genetic variants to congenital hypothyroidism (CH) is not well understood. We aimed to study the genetic variability of exons 3 and 5 of PAX8 gene among a cohort of children with congenital hypothyroidism in correspondence to their clinical aspect. Blood samples were collected from 117 children (63 girls and 54 boys) with CH and enrolled as cases (Group I). All cases underwent biochemical confirmation with low FT4 and high TSH levels and thyroid gland imaging, along with equal number of matched apparently healthy individuals who served as controls (Group II). Genomic materials for exons 3 and 5 of PAX8 gene were extracted, amplified by PCR, detected by electrophoresis, purified, and sequenced by the Sanger technique through the application of ABI 3730x1 DNA Sequencer. Out of 117 cases, eight different effective PAX8 mutations were detected in exon 3 (G23D, V35I, I34T, Q40P, p.R31C, p.R31H, p.R31A, and p.I47T) in 14 patients with their sonographic findings ranged from normal, hypoplastic to thyroid agenesis. Besides the reported mutations, one novel mutation; R31A was detected in 1 euotopic case. Exon 5 analysis revealed no detected mutations elsewhere. In contrast, all healthy control children showed no mutation and normal sonographic findings. Mutations in exon 3 of PAX8 gene, implies its important role in thyroid development and function, as a first estimate of PA8 mutation rate in Egyptian patients with CH having normal and dysgenetic gland. Using ultrasound is mandatory for diagnosis and guiding the treatment of children with CH.
Individual calculation of perfusion activity based on ventilation efficiency for V/P-SPECT
Authors: Bärenfänger Felix , Block Andreas , Schmelz Detlef , Hamami-Arlinghaus Monia
Published: April 2021

Aim Implementation of the individual calculation of perfusion activity to ensure the guideline-compliant ratio of perfusion to ventilation (P/V-ratio) of ≥ 3 in the diagnosis of acute pulmonary embolism (PE) using V/P-SPECT.

Material and Methods 50 consecutive V/P-SPECT examinations, in which a standard activity of 160 MBq was applied for perfusion imaging, are evaluated retrospectively. Based on this patient group an activity factor is determined, which provides a correlation between the applied perfusion activity and the expected perfusion counts of the gamma camera. Using the mean activity factor, the perfusion activity required for a P/V-ratio of four is calculated using the previously acquired ventilation count rate. This is applied prospectively to the 100 subsequent examinations.

Results The mean perfusion activity factor is (54.56 ± 10.13) cps/MBq. The individually calculated perfusion activities range from 80 MBq to 200 MBq with an average value of (146.9 ± 35.3) MBq and a median of 140 MBq. The individual activity calculation thus reduced the mean perfusion activity by 8.2 % and the median by 12.5 %. In addition, the individual calculation reduced the proportion of P/V ratios < 3 from 14 % to 0 % and the proportion of P/V ratios > 5 from 24 % to 19 %.

Conclusion The presented method for the individual calculation of perfusion activity offers a simple way to ensure a guideline-compliant P/V-ratio. Furthermore, unnecessarily high perfusion activity as a result of inadequate ventilation can be avoided.
Withanolides from Withania somnifera Ameliorate Neutrophil Infiltration in Endotoxin-Induced Peritonitis by Regulating Oxidative Stress and Inflammatory Cytokines
Authors: Solleti Siva Kumar , Singh Hoshiyar , Balkrishna Acharya , Sharma Niti , Varshney Anurag
Published: April 2021

Identification of novel anti-inflammatory strategies are needed to avoid the side effects associated with the currently available therapies. Use of anti-inflammatory herbal remedies is gaining attention. The purpose of the present investigation was to evaluate the pharmacological potential of the withanolide-rich root extracts of the medical plant Withania somnifera (L.) Dunal using in vivo and in vitro models of endotoxin-induced inflammation and oxidative stress. The pharmacological effects of W. somnifera root extracts were evaluated using a mouse model of endotoxin (lipopolysaccharide)-induced peritonitis and various relevant human cell lines. HPLC analysis of the W. somnifera root extracts identified the presence of various bioactive withanolides. In vivo challenge of mice with endotoxin resulted in the infiltration of various leukocytes, specifically neutrophils, along with monocytes and lymphocytes into the peritoneal
cavity. Importantly, prophylactic treatment with W. somnifera inhibited the migration of neutrophils, lymphocytes, and monocytes and decreased the release of interleukin-1β, TNF-α, and interleukin-6 cytokines into the peritoneal cavity as identified by ELISA. Liver (glutathione peroxidase, glutathione, glutathione disulfide, superoxide dismutase, malondialdehyde, myeloperoxidase) and peritoneal fluid (nitrite) biochemical analysis revealed the antioxidant profile of W. somnifera. Similarly, in human HepG2 cells, W. somnifera significantly modulated the antioxidant levels. In THP-1 cells, W. somnifera decreased the secretion of interleukin-6 and TNF-α. In HEK-Blue reporter cells, W. somnifera inhibited TNF-α-induced nuclear factor-κB/activator protein 1 transcriptional activity. Our findings suggest the pharmacological effects of root extracts of W. somnifera rich in withanolides
inhibit neutrophil infiltration, oxidative hepatic damage, and cytokine secretion via modulating the nuclear factor-κB/activator protein 1 pathway.
Enhanced Skin Permeation of Punicalagin after Topical Application of Pluronic Micelles or Vesicles Loaded with Lafoensia pacari Extract
Authors: Garcia Sandra Alves de Sousa , da Rocha Priscila Bianca Rodrigues , Souza Bruno dos Santos , Paz Andressa Tuane Santana , Negris Ana Luiza Caetano , Marreto Ricardo Neves , da Conceição Edemilson Cardoso , Bara Maria Teresa Freitas , Taveira Stephânia Fleury
Published: April 2021

Punicalagin, the principal ellagitannin of Lafoensia pacari leaves, has proven antioxidant activity, and standardized extracts of L. pacari can be topically used for skin aging management. We hypothesized that Pluronic nanomicelles or vesicles could solubilize sufficiently large amounts of the standardized extracts of L. pacari and provide chemical stability to punicalagin. The standardized extracts of L. pacari were obtained with an optimized extraction procedure, and the antioxidant activity was characterized. Formulations containing Pluronic at 25% and 35% were obtained with or without Span 80. They were characterized by average diameter, polydispersity index, punicalagin content, physicochemical stability, and rheology. A release and skin permeation study was carried out in vertical diffusion cells. The extraction procedure allowed quantifying high punicalagin content (i.e., 141.61 ± 3.87 mg/g). The standardized extracts of
L. pacari showed antioxidant activity for all evaluated methods. Pluronic at 25 and Pluronic at 35 with standardized extracts of L. pacari showed an average diameter of about 25 nm. The addition of Span 80 significantly increased the mean diameter by 15-fold (p < 0.05), indicating the spontaneous formation of vesicles. Pluronic formulations significantly protected punicalagin from chemical degradation (p < 0.05). Pluronic at 25 formulations presented as free-flowing liquid-like systems, while Pluronic at 35 resulted in an increase of about 44-fold in |ƞ*|. The addition of Span 80 significantly reduced the Pluronic sol-gel transition temperature (p < 0.05), indicating the formation of vesicles. Formulations with Span 80 significantly enhanced punicalagin skin permeation compared to formulations without Span 80 (p < 0.05). Formulations with Span 80 were demonstrated to be the most promising formulations, as they allowed significant permeation of
punicalagin (about 80 to 315 µg/cm2), which has been shown to have antioxidant activity.
Synthesis of Bempedoic Acid through Electrochemical Decarboxylation of Dialkylated Malonic Acid
Authors: Tian Lifang , Wang Yahui , Xu Zhimin , Zheng Yue
Published: April 2021

Bempedoic acid is a small-molecule inhibitor of adenosine triphosphate-citrate lyase (ACL) that is effective in the treatment of hypercholesterolemia and hypertension. In this paper, a new, six-step synthesis of bempedoic acid with 42% overall yield is reported. Ketone formation by electrochemical decarboxylation of dialkylated malonic acid is introduced as the key step of this process. This method uses mild conditions and its high efficiency makes it potentially suitable for industrial production.
Nickel-Catalyzed Decarbonylative Thioetherification of Acyl Fluorides via C–F Bond Activation
Authors: Nishihara Yasushi , You Jingwen , Chen Qiang
Published: April 2021

Nickel-catalyzed decarbonylative thioetherification of acyl fluorides has been developed. This transformation allows an array of acyl fluorides to react with thiophenols. A wide range of functional groups are well tolerated and the corresponding sulfides can be obtained in good to excellent yields. This protocol provides the formation of diverse carbon–sulfur bonds via a highly efficient decarbonylative process.
Organoiodine-Catalyzed Enantioselective Intramolecular Oxy­aminations of Alkenes with N-(Fluorosulfonyl)carbamate
Authors: Hashimoto Takuya , Wata Chisato
Published: April 2021

Organoiodine-catalyzed enantioselective intramolecular oxyaminations were realized by the use of benzyl N-(fluorosulfonyl)carbamate as the exogenous nitrogen source. The method allows access to enantioenriched lactones and oxazolines, starting from γ,δ- and δ,ε-unsaturated esters and N-allyl amides, respectively.
Thromboembolic and Bleeding Events in COVID-19 Patients receiving Extracorporeal Membrane Oxygenation
Authors: Durak Koray , Kersten Alexander , Grottke Oliver , Zayat Rashad , Dreher Michael , Autschbach Rüdiger , Marx Gernot , Marx Nikolaus , Spillner Jan , Kalverkamp Sebastian
Published: April 2021

Background Extracorporeal membrane oxygenation (ECMO) is a potential treatment option in critically ill COVID-19 patients suffering from acute respiratory distress syndrome (ARDS) if mechanical ventilation (MV) is insufficient; however, thromboembolic and bleeding events (TEBE) during ECMO treatment still need to be investigated.

Methods We conducted a retrospective, single-center study including COVID-19 patients treated with ECMO. Additionally, we performed a univariate analysis of 85 pre-ECMO variables to identify factors influencing incidences of thromboembolic events (TEE) and bleeding events (BE), respectively.

Results Seventeen patients were included; the median age was 57 years (interquartile range [IQR]: 51.5–62), 11 patients were males (65%), median ECMO duration was 16 days (IQR: 10.5–22), and the overall survival was 53%. Twelve patients (71%) developed TEBE. We observed 7 patients (41%) who developed TEE and 10 patients (59%) with BE. Upper respiratory tract (URT) bleeding was the most frequent BE with eight cases (47%). Regarding TEE, pulmonary artery embolism (PAE) had the highest incidence with five cases (29%). The comparison of diverse pre-ECMO variables between patients with and without TEBE detected one statistically significant value. The platelet count was significantly lower in the BE group (n = 10) than in the non-BE group (n = 7) with 209 (IQR: 145–238) versus 452 G/L (IQR: 240–560), with p = 0.007.

Conclusion This study describes the incidences of TEE and BE in critically ill COVID-19 patients treated with ECMO. The most common adverse event during ECMO support was bleeding, which occurred at a comparable rate to non-COVID-19 patients treated with ECMO.
Endoscopic Management of Bowel Obstruction
Authors: Beck David E.
Published: April 2021

The traditional morbidity and mortality associated with traditional management has stimulated exploration of endoscopic approaches. Success depends on patient selection, the location and etiology of obstruction, patient status, and the capability of the endoscopist. This article discusses techniques of intralumenal dilation and stent placement and results from systematic reviews.
Endoscopic Management of Enterocutaneous Fistulae
Authors: Mirkin Katelin A. , Pauli Eric M.
Published: April 2021

Enterocutaneous fistulae (ECFs), abnormal epithelialized connections between the small bowel and skin, are associated with significant morbidity, and pose a unique challenge to patients and clinicians. Management of ECF requires sepsis control, effluent management, nutritional support, and local wound care. Traditionally, surgical intervention was required for ECF that failed to close with conservative management. With the rise of therapeutic endoscopy, new management strategies have emerged. Fluoroscopy-guided endoscopy is now used to delineate anatomy and determine potential therapy options. Definitive endoscopic management may involve through-the-scope and over-the-scope clips, or endoscopic suturing devices. Adjuncts to definitive management include removing foreign bodies, alleviating distal obstructions, and de-epithelializing fistula tracts. Even if an ECF is not amenable to definitive endoscopic therapy, endoscopy may help temporize and optimize a patient preoperatively. Endoscopy allows for the placement and repositioning of drains, stent placement to allow for diversion or improved wound care, and the placement of enteric feeding access. As endoscopic techniques expand and more tools become available, the ability to manage complex problems, such as ECF, endoscopically will grow.
Left Ventricular Diastolic Dysfunction and Pulmonary Hypertension: Outcomes in SAVR
Authors: Liu Tom X. , Tanenbaum Mira T. , Seo Claire H. , Park Dan , Lystash John C. , Joseph Mark , Arnold William S.
Published: April 2021

Background Severe pulmonary hypertension (PH) and left ventricular diastolic dysfunction (LVDD) are independently associated with poor outcomes in cardiac surgery. We evaluated the relationship of several measures of LVDD, PH, and hemodynamic subtypes of PH including precapillary pulmonary hypertension(pcPH) and isolated post-capillary pulmonary hypertension(ipcPH) and combined pre and post capillary pulmonary hypertension(cpcPH) capillary PH to postoperative outcomes in a cohort of patients who underwent elective isolated-AVR.

Methods We evaluated (n = 206) patients in our local STS database who underwent elective isolated-AVR between 2014 and 2018, with transthoracic echocardiogram (n = 177) or right heart catheterization (n = 183) within 1 year of operation (or both, n = 161). The primary outcome was a composite end point of death, prolonged ventilation, ICU readmission, and hospital stay >14 days.

Results Severe PH was associated with worse outcomes (moderate: OR, 1.1, p = 0.09; severe: OR, 1.28, p = 0.01), but degree of LVDD was not associated with worse outcomes. Across hemodynamic subtypes of PH, odds of composite outcome were similar (p = 0.89), however, patients with cpcPH had more postoperative complications (67 vs. 36%, p = 0.06) and patients with ipcPH had greater all-cause mortality at 1 (8 vs. 1%, p = 0.03) and 3 years (27 vs. 4%, p = 0.008).

Conclusion Severe PH conferred modestly greater risk of adverse events, and both LVDD grade and the combination of severe PH and LVDD were not associated with worse outcomes. However, hemodynamic stratification of PH revealed higher postoperative complications and worse long-term outcomes for those with cpcPH and ipcPH. Preoperative stratification of PH by hemodynamic subtype in valve replacement surgery may improve our risk stratification in this heterogenous condition. Further evaluation of the significance of LVDD and PH in other cardiac operations is warranted.
Review of Approaches to Developing Intersegmental Plane during Segmentectomy
Authors: Chen Xingshi , Zhang Zhengyuan , Xu Ning , Ma Dongchun , Li Hecheng
Published: April 2021

In recent years, with the popularity of computed tomography (CT) scanning, early lung cancer has been found in a large number of patients, and segmentectomy has been widely used in clinical practice. The development of intersegmental plane is the most critical step in segmentectomy. At present, there are many methods to identify the intersegmental plane. Also, dissection of the intersegmental plane has been a challenge for thoracic surgeons for decades because of the complicated anatomic variations. This study focuses on the safety and efficacy of relevant methods in both identification and dissection of the intersegmental plane in segmentectomy.
A Permissioned Blockchain Network for Security and Sharing of De-identified Tuberculosis Research Data in Brazil
Authors: Lima Vinícius Costa , Bernardi Filipe Andrade , Alves Domingos , Kritski Afrânio Lineu , Galliez Rafael Mello , Rijo Rui Pedro Charters Lopes
Published: April 2021

Background Tuberculosis (TB) is an infectious disease and is among the top 10 causes of death in the world, and Brazil is part of the top 30 high TB burden countries. Data collection is an essential practice in health studies, and the adoption of electronic data capture (EDC) systems can positively increase the experience of data acquisition and analysis. Also, data-sharing capabilities are crucial to the construction of efficient and effective evidence-based decision-making tools for managerial and operational actions in TB services. Data must be held secure and traceable, as well as available and understandable, for authorized parties.

Objectives In this sense, this work aims to propose a blockchain-based approach to build a reusable, decentralized, and de-identified dataset of TB research data, while increasing transparency, accountability, availability, and integrity of raw data collected in EDC systems.

Methods After identifying challenges and gaps, a solution was proposed to tackle them, considering its relevance for TB studies. Data security issues are being addressed by a blockchain network and a lightweight and practical governance model. Research Electronic Data Capture (REDCap) and KoBoToolbox are used as EDC systems in TB research. Mechanisms to de-identify data and aggregate semantics to data are also available.

Results A permissioned blockchain network was built using Kaleido platform. An integration engine integrates the EDC systems with the blockchain network, performing de-identification and aggregating meaning to data. A governance model addresses operational and legal issues for the proper use of data. Finally, a management system facilitates the handling of necessary metadata, and additional applications are available to explore the blockchain and export data.

Conclusions Research data are an important asset not only for the research where it was generated, but also to underpin studies replication and support further investigations. The proposed solution allows the delivery of de-identified databases built in real time by storing data in transactions of a permissioned network, including semantic annotations, as data are being collected in TB research. The governance model promotes the correct use of the solution.
Endoscopic Diagnosis and Treatment of Bariatric Surgery Complications
Authors: Neto Manoel Galvao , Quadros Luiz Gustavo , Azor Fernanda Oliveira
Published: April 2021

Obesity has become a health problem that generates significant expenses for the health system worldwide. It is associated with chronic diseases—such as high blood pressure and diabetes—and some types of cancers. Bariatric surgery is the gold standard in the treatment of morbid obesity. Several endoscopic procedures have emerged to treat the complications of these surgeries in a less invasive way, reducing morbidity and mortality in these patients. This review aims to present the best trend in the endoscopic treatment of bariatric surgery complications.
Steady-state methods for measuring in-plane thermal conductivity of thin films for heat spreading applications
Authors: Hines Nicholas J. , Yates Luke , Foley Brian M. , Cheng Zhe , Bougher Thomas L. , Goorsky Mark S. , Hobart Karl D. , Feygelson Tatyana I. , Tadjer Marko J. , Graham Samuel
Published: April 2021

The development of high thermal conductivity thin film materials for the thermal management of electronics requires accurate and precise methods for characterizing heat spreading capability, namely, in-plane thermal conductivity. However, due to the complex nature of thin film thermal property measurements, resolving the in-plane thermal conductivity of high thermal conductivity anisotropic thin films with high accuracy is particularly challenging. Capable transient techniques exist; however, they usually measure thermal diffusivity and require heat capacity and density to deduce thermal conductivity. Here, we present an explicit uncertainty analysis framework for accurately resolving in-plane thermal conductivity via two independent steady-state thermometry techniques: particle-assisted Raman thermometry and electrical resistance thermometry. Additionally, we establish error-based criteria to determine the limiting experimental conditions that permit the simplifying assumption of one-dimensional thermal conduction to further reduce thermal analysis. We demonstrate the accuracy and precision (<5% uncertainty) of both steady-state techniques through in-plane thermal conductivity measurements of anisotropic nanocrystalline diamond thin films.
Transmission and rainbow trapping of acoustic waves in a fluid medium using gradient-index superlattices
Authors: Xu Bai-qiang , Wu Jiao , Lu Wei , Gu Xin , Zhang Li-juan , Zhang Sai , Zhang Yu
Published: April 2021

Recently, rainbow trapping of acoustic/elastic waves in gradient artificial structures has shown promising applications in energy harvesting and frequency separation. However, the novel phenomenon of acoustic superlattices for underwater acoustic waves has not been explored. In this work, we establish the theoretical model of underwater acoustic waves propagating through the gradient-index superlattice (GISL) by using the transfer matrix method. We show that the combined band structures of infinite sub-superlattices and the transmission curves of finite GISL exhibit Bragg forbidden bands that are wider than those of periodic ones, which implies the occurrence of rainbow trapping. On this basis, the effects of gradient factor, period number, and water thickness are discussed, and the tunability of the trapping range is also explained. Furthermore, simulations with Gaussian beam incidence are performed through finite element methods. The results in frequency-domain and time-domain both indicate perfect performances of energy localization and frequency separation for acoustic waves of different frequencies. Our findings show possibilities for the design of underwater acoustic devices, such as acoustic sensors and frequency dividers.
Linkage of electron emission and breakdown mechanism theories from quantum scales to Paschen's law
Authors: Loveless Amanda M. , Darr Adam M. , Garner Allen L.
Published: April 2021

Numerous applications such as micro- and nanoelectromechanical systems, microplasmas, and directed energy increasingly drive device miniaturization to nanoscale and from vacuum to atmospheric pressure. This wide range of operating conditions and relevant mechanisms complicates the derivation of a single scaling law for electron emission and gas breakdown; therefore, theoretical studies often unify two or three mechanisms piecemeal. This study defines a common set of scaling parameters across the range of dominant mechanisms to derive a theory that links electron emission and breakdown mechanism theories from quantum scales to Paschen's law and yields asymptotic solutions for quantum space-charge limited emission (QSCL), classical space-charge limited emission (CSCL), space-charge limited emission with collisions (MG), Fowler–Nordheim field emission (FN), field emission driven gas breakdown, and classical gas breakdown defined by Paschen's law (PL). These non-dimensionalized equations are universal (true for any gas) across all regimes except for PL, which contains a single, material-dependent parameter. This approach reproduces various nexuses corresponding to the transitions across multiple mechanisms, such as QSCL to CSCL, CSCL to FN, CSCL to MG to FN, and field emission-driven breakdown as described by FN to PL, using a single non-dimensionalization scheme to facilitate experimental designs concerned with crossing these regimes. Furthermore, we demonstrate the conditions for more complicated nexuses, such as matching QSCL, CSCL, MG, and FN. This provides valuable information to experimentalists concerning regimes where slight perturbations in conditions may alter the electron emission mechanism and to theorists concerning the applicability of the asymptotic solutions or reduced nexus theories.
Investigation of Coulomb scattering in terahertz quantum cascade lasers
Authors: Miyoshi Teppei , Ban Dayan
Published: April 2021

Based on rate equation simulation, the impact of ionized-impurity and electron–electron scatterings on the device characteristics of terahertz (THz) quantum cascade lasers (QCLs) is investigated. This study applies the discretized Fourier transform to speed up the calculation of electron–electron scattering term and improves the calculation time by three orders without impairing accuracy. In addition, a screening effect model, which is necessary for the Coulomb scattering rate calculation, is also carefully selected. An indirectly pumped THz QCL and two types of direct resonant-phonon devices are chosen as examples in this study. The simulation results show that the influence of Coulomb scatterings varies according to device structures. Therefore, it is preferable to include physical models of these carrier scattering phenomena in the simulation when the highest operation temperature is predicted. In addition, this study also discusses the necessity of a pure dephasing time model.
Development of the materials analysis and particle probe for Proto-MPEX
Authors: Beers C. J. , Jaramillo C. , Reid N. C. , Schamis H. , Allain J. P. , Caughman J. B. O. , Meitner S. J. , Rapp J. , Zinkle S. J.
Published: April 2021

The Prototype Material Plasma Exposure eXperiment (Proto-MPEX) is a linear plasma device being used in plasma source research and development (R&D) for the proposed MPEX. Once the R&D is completed, this device can also be used to perform plasma–material interaction studies. To perform these studies, a new materials analysis and particle probe (MAPP) has been constructed. The MAPP’s components are a sample holder and manipulator and a custom vacuum chamber with ports to facilitate surface chemistry diagnostics. The MAPP’s overall design enables rapid sample turnaround and in vacuo surface characterization. The surface analysis vacuum chamber has ports for x-ray photoelectron spectroscopy, thermal desorption spectroscopy, back-scatter ion scattering spectroscopy, forward-scatter ion scattering spectroscopy, and direct recoil spectroscopy. The sample manipulator and holder is a Lesker/UHV Multi-Centre Analytical Stage, which is used to place the samples in the exposure region of the Proto-MPEX or the analysis position in the MAPP vacuum chamber. The sample holder has a heating capability of up to 1200 °C for heated exposure and for desorption studies. In this work, we present the MAPP’s design and the first tungsten sample exposure with ex situ analysis that shows a surface deposition layer on the exposed target, highlighting the need for additional in situ measurements on the Proto-MPEX.
Phase separation in mixed suspensions of bacteria and nonadsorbing polymers
Authors: Peters V. F. D. , Vis M. , Tuinier R. , Lekkerkerker H. N. W.
Published: April 2021

The shapes of bacteria can vary widely; they may, for instance, be spherical, rod-like, string-like, or curved. In general, bacilli are highly anisotropic. For research and (bio)technological purposes, it can be useful to concentrate bacteria, which is possible by adding nonadsorbing polymers. The induced phase separation originates from a polymer-mediated depletion interaction, first understood by Asakura and Oosawa. Here, it is shown that free volume theory (FVT) can semi-quantitatively describe the phase transitions observed when adding sodium polystyrene sulfonate polymers to E. coli bacteria [Schwarz-Linek et al., Soft Matter 6, 4540 (2010)] at high ionic strength. The E. coli bacteria are described as short, hard spherocylinders. FVT predicts that the phase transitions of the mixtures result from a fluid–ABC crystal solid phase coexistence of a hard spherocylinder–polymer mixture.
Modulation of electronic and magnetic properties of monolayer chromium trihalides by alloy and strain engineering
Authors: Wang Qian , Han Nannan , Zhang Xuyang , Zhang Chenhui , Zhang Xixiang , Cheng Yingchun
Published: April 2021

Monolayer CrI3 is a rare ferromagnetic semiconductor with intrinsic long-range magnetic order, which makes it a great potential material in spintronic devices [Song et al., Science 360, 1214 (2018)]. To extend the applications of monolayer CrI3 in flexible devices, the modulation of its electronic and magnetic properties is important. Here, we investigated the combined effect of strain and alloy on the properties of monolayer CrI3 by first-principles calculations. Br is chosen as the alloyed element due to the similar atomic configuration and property of CrX3 (X = Br, I), and the strain is applied by simultaneously changing the in-plane lattice constants (a and b). We find that the bandgap of monolayer Cr2I6−xBrx can be tuned greatly, while the magnetic moment of monolayer Cr2I6−xBrx is regulated very little under different strain and Br concentration. This unique property of monolayer Cr2I6−xBrx under strain makes it a good candidate for the flexible spintronic devices.
Layer and spontaneous polarizations in perovskite oxides and their interplay in multiferroic bismuth ferrite
Authors: Spaldin Nicola A. , Efe Ipek , Rossell Marta D. , Gattinoni Chiara
Published: April 2021

We review the concept of surface charge, first, in the context of the polarization in ferroelectric materials and, second, in the context of layers of charged ions in ionic insulators. While the former is traditionally discussed in the ferroelectrics community and the latter in the surface science community, we remind the reader that the two descriptions are conveniently unified within the modern theory of polarization. In both cases, the surface charge leads to electrostatic instability—the so-called “polar catastrophe”—if it is not compensated, and we review the range of phenomena that arise as a result of different compensation mechanisms. We illustrate these concepts using the example of the prototypical multiferroic bismuth ferrite, BiFeO3, which is unusual in that its spontaneous ferroelectric polarization and the polarization arising from its layer charges can be of the same magnitude. As a result, for certain combinations of polarization orientation and surface termination, its surface charge is self-compensating. We use density functional calculations of BiFeO3 slabs and superlattices, analysis of high-resolution transmission electron micrographs, and examples from the literature to explore the consequences of this peculiarity.
Electron heating and cooling in hypersonic flows
Authors: Parent B.
Published: April 2021

Using recently developed advanced numerical methods for plasma flows and sheaths, the first detailed study of electron cooling and heating taking place within hypersonic non-neutral flows is presented here. The numerical simulations fully couple the Navier–Stokes equations for the neutrals to the drift–diffusion model for the electrons and ions and include a 11-species finite-rate chemical solver along with a transport equation for the electron temperature in non-equilibrium. Results for Mach 18 airflow around a wedge with a sharp leading edge show that at low flight dynamic pressure the electron temperature remains close to the freestream temperature in the stagnation region. Such is attributed to the product of the electric field and the electron current being dominantly negative within the plasma sheaths and acting as an electron energy sink. This cooling effect leads to a significant portion of the flow downstream of the shock exhibiting electron temperatures much lower than expected. This study is the first to show a large impact of the non-neutral plasma sheaths on the post-shock electron temperature. This study also shows that the common approach to set the electron temperature equal to the vibrational temperature can result in the electron temperature being over-predicted by one order of magnitude or more in hypersonic flows.
A hybrid topological and shape-matching approach for structure analysis
Authors: Goswami Amrita , Singh Jayant K.
Published: April 2021

Properties of crystalline and amorphous materials are characterized by the underlying long-range and local crystalline order. Deformations and defects are structural hallmarks of plasticity, ice formation, and crystal growth mechanisms. Partitioning topological networks into constituent crystal building blocks, which is the basis of topological identification criteria, is an intuitive approach for classification in both bulk and confinement. However, techniques reliant on the convex hull for assigning orientations of component units fail for non-convex blocks. Here, we propose a new framework, called Topological Unit Matching (TUM), which exploits information from topological criteria for an efficient shape-matching procedure. TUM is a general family of algorithms, capable of quantifying deformations and unambiguously determining grains of bulk and confined ice polymorphs. We show that TUM significantly improves the identification of quasi-one-dimensional ice by including deformed prism blocks. We demonstrate the efficacy of TUM by analyzing supercooled water nanoparticles, amorphous ice, and phase transitions in an ice nanotube. We also illustrate the superiority of TUM in resolving topological defect structures with minimal parameterization.
Stress-gradient-induced migration effects on the elastic instabilities of wormlike micellar solutions in a cross-slot flow
Authors: Forte Neto F. S. , da Cruz A. G. B.
Published: April 2021

Using the two-species VCM model, we report the effects of stress-gradient-induced migration on the elastic instabilities of a wormlike micellar solution flowing through a cross-slot microchannel. The model was solved using a mixed finite element method in the open-source platform FEniCS. The stress-gradient-induced migration due to the non-Fickian (conformation) fluxes changes the onset of the instability and symmetry breaking and the size of secondary flow patterns upstream of the cross-channel corner. Varying the chain scission and micellar extensibility parameter, we observed that the suppression of asymmetric flow instability occurs at a different rate with the effects of migration. These results suggest that conformation force-driven migration has an influence on the onset of flow instability and should not be neglected a priori.
Quantum dynamics of Mn2+ in dimethylammonium magnesium formate
Authors: Orio M. , Bindra J. K. , van Tol J. , Giorgi M. , Dalal N. S. , Bertaina S.
Published: April 2021

Dimethylammonium magnesium formate, [(CH3)2NH2][Mg(HCOO)3] or DMAMgF, is a model used to study high temperature hybrid perovskite-like dielectrics. This compound displays an order–disorder phase transition at about 260 K. Using multifrequency electron spin resonance in continuous wave and pulsed modes, we herein present the quantum dynamics of the Mn2+ ion probe in DMAMgF. In the high temperature paraelectric phase, we observe a large distribution of the zero field splitting that is attributed to the high local disorder and further supported by density functional theory computations. In the low temperature ferroelastic phase, a single structure phase is detected and shown to contain two magnetic structures. The complex electron paramagnetic resonance signals were identified by means of the Rabi oscillation method combined with the crystal field kernel density estimation.
Vibration-mediated resonant charge separation across the donor–acceptor interface in an organic photovoltaic device
Authors: Hu Ziyang , Xu Ziyao , Chen GuanHua
Published: April 2021

Examination of a recent open-system Ehrenfest dynamics simulation suggests that a vibration-mediate resonance may play a pivotal role in the charge transfer across a donor–acceptor interface in an organic solar cell. Based on this, a concise dissipative two-level electronic system coupled to a molecular vibrational mode is proposed and solved quantum mechanically. It is found that the charge transfer is enhanced substantially when the vibrational energy quanta is equal to the electronic energy loss across the interface. This vibration-mediate resonant charge transfer process is ultrafast, occurring within 100 fs, comparable to experimental findings. The open-system Ehrenfest dynamics simulation of the two-level model is carried out, and similar results are obtained, which confirms further that the earlier open-system Ehrenfest dynamics simulation indeed correctly predicted the occurrence of the resonant charge transfer across the donor–acceptor interface.
Molecular cloning, characterisation and expression analysis of the vitellogenin genes
Authors: Jiang Huayu , Tang Daojun , Gao Xinming , Lin Chenwen , Feng Binbin , Du Chen , Jin Shan , Zhu Junquan
Published: April 2021

Vitellogenesis is essential for oocyte maturation. Vitellogenin (Vtg), a yolk precursor protein, plays an important role in oogenesis and vitellogenesis. Chinese hook snout carp Opsariichthys bidens is an economically important freshwater fish in China whose reproductive and developmental biology are not well understood. In this study, we undertook histological analysis to examine ovary development and oogenesis in O. bidens. The ovaries were divided into Stages II–V and oocytes were divided into perinuclear oocytes, cortical alveoli oocytes, vitellogenic oocytes and mature oocytes. Full-length cDNA sequences were cloned of two vtg genes from the liver of O. bidens, namely Ob-vtgAo1 and Ob-vtgC. Ob-vtgAo1 and Ob-vtgC cDNA are made up of 4136 and 4392 bases respectively and encode proteins containing 1335 and 1250 amino acids respectively. Ob-vtgAo1 contains three yolk protein domains: lipovitellin heavy chain (LvH), phosvitin (Pv) and lipovitellin light chain (LvL), whereas Ob-VtgC contains LvH and LvL, which are incomplete Vtgs. Ob-vtgAo1 and Ob-vtgC mRNA expression was significantly higher in the liver of O. bidens than in all other tissues. In oocytes of Stage II–III ovaries, yolk granules are almost absent and ovarian and hepatic Ob-vtgAo1 and Ob-vtgC expression is low. At Stage IV, the oocyte is filled with yolk granules and ovarian and hepatic Ob-vtgAo1 and Ob-vtgC expression is significantly increased. Collectively, these findings help us better understand vitellogenesis in O. bidens.
A high-throughput microfluidic nanoimmunoassay for detecting anti–SARS-CoV-2 antibodies in serum or ultralow-volume blood samples
Authors: Swank Zoe , Michielin Grégoire , Yip Hon Ming , Cohen Patrick , Andrey Diego O. , Vuilleumier Nicolas , Kaiser Laurent , Eckerle Isabella , Meyer Benjamin , Maerkl Sebastian J.
Published: April 2021

Significance

COVID-19, caused by SARS-CoV-2, led to an unprecedented global health crisis. As the majority of people infected with SARS-CoV-2 have no or only mild symptoms, many cases aren’t captured by direct testing. However, it is important to establish the true spread of the virus by identifying how many people have been exposed. Detection of anti–SARS-CoV-2–specific antibodies in blood samples can help us understand how the pandemic is evolving over time. We developed a sensitive and specific assay that performs 1,024 measurements in parallel. To enable decentralized blood sample collection, the method can detect antibodies in a small drop of blood obtainable by finger pricking, and the blood can be collected and shipped with a simple, low-cost blood glucose test strip.
Total knee arthroplasty in the past three decades: Trends in patient characteristics and implant survivorship
Authors: Nagira Keita , Hagino Hiroshi , Enokida Makoto , Enokida Shinpei , Ishida Koji , Hayashi Ikuta , Nagashima Hideki
Published: April 2021

Objective

To explore the trends in patient characteristics and implant survivorship (IS) for primary total knee arthroplasty (TKA) over the past three decades.

Methods

This retrospective study enrolled a total of 635 knees who underwent TKA from 1985 to 2014. They were divided into three groups: group A, 125 knees in 1985–1994; group B, 203 knees in 1995–2004; and group C, 307 knees A in 2005–2014. The patient characteristics and IS were compared.

Results

The mean age of patients undergoing TKA was getting older: 65.3 ± 9.7, 69.1 ± 10.0, and 74.6 ± 8.4 years, in groups A, B, and C, respectively (p = .001). The proportion of patients <60 years old with RA decreased (p < .001), whereas that of patients ≥ 80 years old with OA increased dramatically, it was 7.0%, 14.5%, and 32.0% in groups A, B, and C, respectively (p < .001). The IS free from infection was over 98% in all groups. Alternatively, the IS free from aseptic loosening become better, it was 83.7%, 95.2%, and 98.2% in groups A, B, and C, respectively (p = .014).

Conclusions

From these trends, we can estimate that the number of patients undergoing TKA will further increase in the future in an aging society.
Telomere erosion in human pluripotent stem cells leads to ATR-mediated mitotic catastrophe
Authors: Vessoni Alexandre T. , Zhang Tianpeng , Quinet Annabel , Jeong Ho-Chang , Munroe Michael , Wood Matthew , Tedone Enzo , Vindigni Alessandro , Shay Jerry W. , Greenberg Roger A. , Batista Luis F.Z.
Published: April 2021

It is well established that short telomeres activate an ATM-driven DNA damage response that leads to senescence in terminally differentiated cells. However, technical limitations have hampered our understanding of how telomere shortening is signaled in human stem cells. Here, we show that telomere attrition induces ssDNA accumulation (G-strand) at telomeres in human pluripotent stem cells (hPSCs), but not in their differentiated progeny. This led to a unique role for ATR in the response of hPSCs to telomere shortening that culminated in an extended S/G2 cell cycle phase and a longer period of mitosis, which was associated with aneuploidy and mitotic catastrophe. Loss of p53 increased resistance to death, at the expense of increased mitotic abnormalities in hPSCs. Taken together, our data reveal an unexpected dominant role of ATR in hPSCs, combined with unique cell cycle abnormalities and, ultimately, consequences distinct from those observed in their isogenic differentiated counterparts.
Stationary spacetimes with time-dependent real scalar fields
Authors: Franzin Edgardo , Smolić Ivica
Published: April 2021

In 1981 Wyman classified the solutions of the Einstein–Klein–Gordon equations with static spherically symmetric spacetime metric and vanishing scalar potential. For one of these classes, the scalar field linearly grows with time. We generalize this symmetry noninheriting solution, perturbatively, to a rotating one and extend the static solution exactly to arbitrary spacetime dimensions. Furthermore, we investigate the existence of nonminimally coupled, time-dependent real scalar fields on top of static black holes, and prove a no-hair theorem for stealth scalar fields on the Schwarzschild background.
Inflationary magnetogenesis in the perturbative regime
Authors: Giovannini Massimo
Published: April 2021

While during inflation a phase of increasing gauge coupling allows for a scale-invariant hyperelectric spectrum, when the coupling decreases a flat hypermagnetic spectrum can be generated for typical wavelengths larger than the effective horizon. After the gauge coupling flattens out the late-time hypermagnetic power spectra outside the horizon in the radiation epoch are determined by the hyperelectric fields at the end of inflation whereas the opposite is true in the case of decreasing coupling. Instead of imposing an abrupt freeze after inflation, we consider a smooth evolution of the mode functions by positing that the gauge couplings and their conformal time derivatives are always continuous together with the background extrinsic curvature. The amplified gauge power spectra are classified according to their transformation properties under the duality symmetry. After clarifying the role of the comoving and of the physical spectra in the formulation of the relevant magnetogenesis constraints, the parameter space of the scenario is scrutinized. It turns out that a slightly blue hyperelectric spectrum during inflation may lead to a quasi-flat hypermagnetic spectrum prior to matter radiation equality and before the relevant wavelengths reenter the effective horizon. In this framework the gauge coupling is always perturbative but the induced large-scale magnetic fields can be of the order of a few hundredths of a nG and over typical length scales between a fraction of the Mpc and 100 Mpc prior to the gravitational collapse of the protogalaxy.
Method for environmental noise estimation via injection tests for ground-based gravitational wave detectors
Authors: Washimi T , Yokozawa T , Tanaka T , Itoh Y , Kume J , Yokoyama J
Published: April 2021

Environmental noise is one of the critical issues for the observation of gravitational waves, but is difficult to predict in advance. Therefore, to evaluate the adverse impact of environmental noise on the detector sensitivity, understanding the detector response to the environmental noise in actual setup is crucial, for both the observation and future upgrades. In this paper, we introduce and verify a new method of the environmental noise injection test based on the post-observation commissioning of KAGRA. This new method (response function model) includes the frequency conversion and nonlinearity of power, which are the effects that are not considered in the current model (coupling function model) used in LIGO and Virgo. We also confirmed the validity of our method by applying it to an environmental noise-enriched dataset and successfully reproducing them.
Focus on physics competitions—a résumé concerning submissions in 2020 and an encouragement for future submissions
Authors: Fösel A
Published: April 2021

The journal collection ‘Focus on Physics Competitions’ of the European Journal of Physics (EJP) is an ongoing collection within the European Journal Physics (EJP). In the year 2020, five articles have been submitted within this series. This editorial will briefly sum up the content and ideas of those articles. In addition, the concept of this collection is explained in order to ensure the objectives of this collection are clear and evident for future submissions.