bluuebunny/crossref_metadata_2025 huggingface dataset:
Hydrogenolysis of glycerol in an aqueous medium over Pt/WO3/zirconium phosphate catalysts studied by 1H NMR spectroscopy
Authors: Bhowmik Susmita , Enjamuri Nagasuresh , Darbha Srinivas
Published: February 2021

Pt/WO3/zirconium phosphate shows high catalytic activity for C–O bond hydrogenolysis of glycerol in an aqueous medium, and 1H NMR is demonstrated as a simple, alternative technique for quantifying the hydrogenolysis products.
Magneto-structural correlations of cyclo-tetravanadates functionalized with mixed-ligand copper(ii) complexes
Authors: Sánchez-Lara Eduardo , García-García Amalia , González-Vergara Enrique , Cepeda Javier , Rodríguez-Diéguez Antonio
Published: February 2021

Bimetallic materials based on tetravanadate anions and mixed ligand copper(ii) complexes were readily synthesized under non-hydrothermal conditions. The compounds show interesting structural and magnetic diversity mediated by copper symmetry.
Structural characterization of naphthalene sulfonamides and a sulfonate ester and their in vitro efficacy against Leishmania tarentolae promastigotes
Authors: Li Edward W. , Katinas Jade , Jones Marjorie A. , Hamaker Christopher G.
Published: February 2021

Structural and biological activity analyses of two naphthalene sulfonamides and a naphthalene sulfonate ester.
Dissipative non-equilibrium dynamics of self-assembled paramagnetic colloidal clusters
Authors: Elismaili Mohammed , Bécu Lydiane , Xu Hong , Gonzalez-Rodriguez David
Published: February 2021

We study experimentally and theoretically the dynamics of two-dimensional clusters of paramagnetic colloids under a time-varying magnetic field.
Intrinsically stretchable polymer semiconductors: molecular design, processing and device applications
Authors: Tien Hsin-Chiao , Huang Yen-Wen , Chiu Yu-Cheng , Cheng Yu-Hsuan , Chueh Chu-Chen , Lee Wen-Ya
Published: February 2021

This review surveys the current developments of intrinsic stretchable polymer semiconductors, including backbone and side-chain engineering, polymer blending, fabrication processes and their next-generation biomimicking applications.
Interaction of cyclosporin A molecules with alkali and transition metal atoms on Cu(111)
Authors: Guo Yuanyuan , Jiang Li , Seitsonen Ari Paavo , Zhang Bodong , Reichert Joachim , Papageorgiou Anthoula C. , Barth Johannes V.
Published: February 2021

Discriminatory on-surface complexation by the natural peptide CsA: up to two K atoms within its macrocycle, Co to residue 9 and the macrocycle, Fe non-selectively.
The antibacterial activities of MoS2 nanosheets towards multi-drug resistant bacteria
Authors: Zhao Yingcan , Jia Yuexiao , Xu Jiayi , Han Liang , He Feng , Jiang Xingyu
Published: February 2021

We demonstrated that molybdenum disulfide (MoS2) nanosheets can be an excellent solar disinfection agent for multi-drug resistant (MDR) bacteria with disinfection efficiencies >99.9999% in only 30 min.
Aromaticity in catalysis: metal ligand cooperation via ligand dearomatization and rearomatization
Authors: Gonçalves Théo P. , Dutta Indranil , Huang Kuo-Wei
Published: February 2021

This feature article describes the recent conceptual understanding of aromaticity and its contribution to the thermodynamics in the catalytic process involving dearomatization and aromatization steps via metal-ligand cooperation.
Tuning the Lewis acidity of metal–organic frameworks for enhanced catalysis
Authors: Devulapalli Venkata Swaroopa Datta , Richard Mélissandre , Luo Tian-Yi , De Souza Mattheus L. , Rosi Nathaniel L. , Borguet Eric
Published: February 2021

The kinetics of hydrolysis of dimethyl nitrophenyl phosphate (DMNP), a simulant of the nerve agent Soman, was studied and revealed transition metal salts as catalysts.
Metal-free amino-controlled electrochemical intramolecular C–O and C–N couplings by site-selective activation of aryl C–N and C–O bonds
Authors: Luo Mu-Jia , Lv Gui-Fen , Li Yang , Li Jin-Heng
Published: February 2021

Metal-free amino-assisted electrochemical intramolecular C–O or C–N couplings of amino-2-(2-aminoaryl)phenols are described.
Group VIII coordination complexes of bidentate P^N ligands bearing π-extended quinoline or phenanthridine N-heterocycles
Authors: Mondal Rajarshi , Braun Jason D. , Lozada Issiah B. , Nickel Rachel , van Lierop Johan , Herbert David E.
Published: February 2021

Group 8 complexes of π-extended N-heterocyclic ligands present some unexpected results. Benzannulation shifts the lowest energy excitation to the blue by impacting the character of the transition rather than affecting frontier orbital energies.
An imine linked fluorescent covalent organic cage: the sensing of chloroform vapour and metal ions, and the detection of nitroaromatics
Authors: Gajula Ramesh Kumar , Mohanty Subhrajit , Chakraborty Manjari , Sarkar Moloy , Prakash M. Jaya
Published: February 2021

Fluorescent covalent organic cage molecule (F-COC) showed enhanced emission intensity in chloroform solution and polymer matrix film form in presence of chloroform vapours.
‘Sweeping rods’: cargo transport by self-propelled bimetallic microrods moving perpendicular to their long axis
Authors: Arslanova Alina , Dugyala Venkateshwar Rao , Reichel Erwin Konrad , Reddy Naveen , Fransaer Jan , Clasen Christian
Published: February 2021

We report for the first time on a much more effective one-by-one microscopic cargo collection and transport by sideways propelled Janus cylinders, which eventually results in pyramidical shaped micro-rod-cargo aggregates.
Development of an Oral Care Multidisciplinary Initiative in an Acute Care Community Hospital: Framework, Timeline, and Outcomes
Authors: Wennerholm Laurie , Perez Nilsa Rubin , Abt Suzanne , Fon Karen , Elsabrout Kerri
Published: February 2021

Purpose

Published literature universally supports the provision of oral care in acute care settings to decrease hospital-acquired aspiration pneumonia (HAAP) events. This evidence-based practice project aimed to implement a comprehensive oral care initiative to reduce a problematic HAAP rate.

Method

Through a comprehensive, multidisciplinary approach, the project scope included an assessment of the current state of oral care delivery, development of an Oral Care Task Force, creation of risk stratification criteria with recommended oral care products, and robust education for the clinical staff. Data were gathered using a small convenience sample of inpatients and hospital-wide HAAP rates.

Results

Over the 1 year of implementation and education associated with this multidisciplinary project, the organization saw an increase in oral care tools being available to patients and staff at the bedside, an increase in patients' awareness of oral care tools in their rooms, and a decrease in the overall HAAP rate.

Conclusions

Creating a multidisciplinary team within an acute care organization with a focus on oral care delivery can be substantially advantageous to patients and hospitals alike. Although this project was limited in its analysis, the demonstrated results are nonetheless interesting and may be applicable to other acute care settings. Ultimately, attention to the importance of oral care and consistent care delivery can provide improved patient outcomes.
Dysphagia Management in Military Service Members With Polytrauma: Overview and Case Report
Authors: Cord Laura L. , Rajpal Veena , Solomon Nancy Pearl
Published: February 2021

Purpose

At Walter Reed National Military Medical Center, service members (SMs) with polytraumatic injuries, usually resulting from blast explosions, are routinely referred to the Speech Pathology Clinic for evaluation of swallowing function. The purpose of this clinical focus article is to advance the speech-language pathologist's (SLP) knowledge of polytrauma and to improve the care of individuals with traumatic injuries, especially related to nutrition and swallowing within a larger multidisciplinary team approach.

Case Report

Previous research within our center identified common demographic and injury characteristics of SMs with combat-related injuries that led to referrals for swallowing evaluation. An SM with polytraumatic injuries was selected for this case report to illustrate the relevance of the research findings and also the importance of multidisciplinary team support to appropriately manage such complex cases. Evaluations and relevant treatments are described across a 3-month acute care hospitalization, including swallowing and nutritional recommendations at the time of each swallowing evaluation.

Discussion

Comparisons of polytrauma cases at Walter Reed National Military Medical Center with literature from civilian trauma centers revealed somewhat longer hospitalizations and the particular influence of maxillofacial trauma on dysphagia outcomes. The complex case reported in this article illustrates the importance of multidisciplinary care and coordination, with particular emphasis on the intersecting roles of the SLP and registered dietitian. This report can serve as a guide for SLPs working in trauma settings for developing prognostic statements, treatment plans, and multidisciplinary interaction.
Electricity price forecasting on electricity spot market: a case study based on the Brazilian Difference Settlement Price
Authors: Silveira Gontijo Tiago , Azevedo Costa Marcelo , Barbosa de Santis Rodrigo
Published: February 2021

Developing predictive models is a complex task since it deals with the uncertainty and the stochastic behavior of variables. Specifically concerning commodities, accurately predicting their future prices allows us to minimize risks and establish more reliable decision support mechanisms. Although the discussion on this question is extensive, there is academic attention being paid to the construction of nonparametric models applied to energy markets, as they have presented promising predictive results, what justifies the present study. This paper applies classical statistical models and Dynamic Time Scan Forecasting (DTSF) to the short-term electricity market prices, in Brazil, from 2006 to 2019. DTSF consists of scanning a time series and then identifying past patterns (so-called “matches”), similar to the last available observations. We predict Brazilian electricity spot prices, according the most similar matches, using aggregation functions, such as median. Recent research on the electricity spot market is increasing, indicating research significance. Our predictive approach exhibited greater accuracy than seminal statistical models. Our approach was designed for a high frequency series. Its predictive performance remained robust when other models presented both high predictive errors (spring), as well as when those models are highly accurate (winter). For future research, we recommend a more finely-tune study on DTSF parameters.
Multiagent Simulation of Demand Flexibility Integration in Local Energy Markets
Authors: Pinto Tiago , Boeno Nathalia , Vale Zita , Sica Everthon
Published: February 2021

Overcoming the issues associated with the variability of renewable generation has become a constant challenge in power and energy systems. The use of load flexibility is one of the most promising ways to face it. Suitable ways to incorporate flexibility in the electricity market, in addition to the already challenging integration of distributed generation primary sources, are therefore crucial. The integration of prosumers and consumers flexibility in the market is, however, not straightforward, as current wholesale and retail market structures are not prepared to deal with the current and future needs of the system. Several models for local energy markets have been studied and experimented; but there it is still not clear what is the most efficient way to integrate the dynamic participation of demand flexibility in this type of local markets.
Photovoltaic panels tilt angle optimization
Authors: Sado Kerry A. , Hassan Lokman H. , Sado Shivan
Published: February 2021

The tilt angle of solar panels is significant for capturing solar radiation that reaches the surface of the panel. Photovoltaic (PV) performance and efficiency are highly affected by its angle of tilt with respect to the horizontal plane. The amount of radiation reaching the surface of a PV panel changes with the changes in its tilt angle, hence adding a solar tracking system will maximize the amount of solar radiation reaching the surface of a PV panel at any time during the day, however, integrating solar tracking system will increase the total cost and maintenance of any PV system. Thus, using an optimized fixed tilt angle is the solution to element the initial, maintenance, and operation costs of a solar tracking system. Yet, the fixed angle is location-specific because it depends on the daily, monthly, and yearly location of the sun. In this study; daily, monthly and seasonally angles are calculated mathematically and the amount of incident radiation on the surface of the PV panel is measured along with its voltage. By comparing the practical measurements of the output voltage of PV panels, an optimized tilt angle is decided.
Micro milling process modeling: a review
Authors: Mamedov Ali
Published: February 2021

The trend towards miniature manufacturing in high technological fields like bioengineering, electronics and aerospace has increased dramatically over the last decade. Many methods of micro manufacturing have been researched and applied to manufacture small scale components. Among these manufacturing methods micro-mechanical machining methods have shown themselves to be attractive alternatives. Micro milling is one of the most frequently used micro-mechanical machining method with high potential for the precise manufacturing of complex parts. The aim of this work is to present the principal aspects related to micro milling technology, with emphasis on process modeling and quality of the finished product. A general view on process modeling starting from chip thickness models up to tool and workpiece machining induced distortion models is depicted. Specifically, different modeling techniques related to modeling of micro milling process are evaluated and important aspects that authors revealed during their research are presented. Finally, implications are discussed and suggestions for future research are presented.
Physiochemical properties of Saudi Nigella sativa L. (‘Black cumin’) seed oil
Authors: Farhan Nesrain , Salih Nadia , Salimon Jumat
Published: February 2021

The seeds of Nigella sativa L. (Ranunculaceae), commonly known as black cumin seeds and Habat Al-barkah in Saudi Arabia, are used extensively for flavouring and medicinal purposes. This work reported the study of physiochemical properties of Saudi black cumin seed oil (BCSO). The results of hexane extraction showed that black cumin seeds are rich in oil (43.7%). All the oil samples show high saponification values and low unsaponification values. High iodine values (122.7 mg/100 g) showed high degree of unsaturation (86%) for Saudi BCSO with about 60% of dominant linoleic acid (C18:2). The volatile compounds presence in Saudi BCSO were extracted using steam distillation method and analyzed using gas chromatography mass spectrometer (GC/MS). The results showed that the volatile compounds such as p-cymene (31.50 ± 0.51%) and thymoquinone (25.35 ± 0.37%) were dominantly high in Saudi BCSO. Other compounds such as 3,5-dimethyl cyclohexanol, α-thujene, carvacrol, paeonol and longifolene were also present. Vitamin E was analyzed using High performance liquid chromatography (HPLC)-fluorescence method. The total concentrations of vitamin E were 451 ppm. The Saudi BCSO showed high content of linoleic acid (59.8%). The HPLC results showed that major triacylglycerols (TAGs) of Saudi BCSO were 1-oleoyl-2,3-dilinoleoylglycerol (OLL; 37.7 ± 0.4%) and 1,2,3-trilinoleylglycerol (LLL; 35.9 ± 0.3%). On the other hand, minor TAGs present were 1-palmitoyl-2,3-dilinoleylglycerol (PLL; 6.7 ± 0.9%), 1,2,3-trioleylglycerol (OOO; 6.4 ± 0.5%) and 1,2-dioleyl-3-linoleylglycerol (OOL; 5.7 ± 1.1%). The Saudi BCSO exhibited specific physicochemical properties and might be used for medicinal applications.
Surgical Management of Pediatric Inguinal Hernia: A Systematic Review and Guideline from the European Pediatric Surgeons' Association Evidence and Guideline Committee
Authors: Morini Francesco , Dreuning Kelly M.A. , Janssen Lok Maarten J.H. , Wester Tomas , Derikx Joep P.M. , Friedmacher Florian , Miyake Hiromu , Zhu Haitao , Pio Luca , Lacher Martin , Sgró Stefania , Zani Augusto , Eaton Simon , van Heurn L.W. Ernest , Pierro Agostino
Published: February 2021

Introduction Inguinal hernia repair represents the most common operation in childhood; however, consensus about the optimal management is lacking. Hence, recommendations for clinical practice are needed. This study assesses the available evidence and compiles recommendations on pediatric inguinal hernia.

Materials and Methods The European Pediatric Surgeons' Association Evidence and Guideline Committee addressed six questions on pediatric inguinal hernia repair with the following topics: (1) open versus laparoscopic repair, (2) extraperitoneal versus transperitoneal repair, (3) contralateral exploration, (4) surgical timing, (5) anesthesia technique in preterm infants, and (6) operation urgency in girls with irreducible ovarian hernia. Systematic literature searches were performed using PubMed, MEDLINE, Embase (Ovid), and The Cochrane Library. Reviews and meta-analyses were conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) statement.

Results Seventy-two out of 5,173 articles were included, 27 in the meta-analyses. Laparoscopic repair shortens bilateral operation time compared with open repair. In preterm infants, hernia repair after neonatal intensive care unit (NICU)/hospital discharge is associated with less respiratory difficulties and recurrences, regional anesthesia is associated with a decrease of postoperative apnea and pain. The review regarding operation urgency for irreducible ovarian hernia gained insufficient evidence of low quality.

Conclusion Laparoscopic repair may be beneficial for children with bilateral hernia and preterm infants may benefit using regional anesthesia and postponing surgery. However, no definite superiority was found and available evidence was of moderate-to-low quality. Evidence for other topics was less conclusive. For the optimal management of inguinal hernia repair, a tailored approach is recommended taking into account the local facilities, resources, and expertise of the medical team involved.
Cellular Senescence in Liver Disease and Regeneration
Authors: Ferreira-Gonzalez Sofia , Rodrigo-Torres Daniel , Gadd Victoria L. , Forbes Stuart J.
Published: February 2021

Cellular senescence is an irreversible cell cycle arrest implemented by the cell as a result of stressful insults. Characterized by phenotypic alterations, including secretome changes and genomic instability, senescence is capable of exerting both detrimental and beneficial processes. Accumulating evidence has shown that cellular senescence plays a relevant role in the occurrence and development of liver disease, as a mechanism to contain damage and promote regeneration, but also characterizing the onset and correlating with the extent of damage. The evidence of senescent mechanisms acting on the cell populations of the liver will be described including the role of markers to detect cellular senescence. Overall, this review intends to summarize the role of senescence in liver homeostasis, injury, disease, and regeneration.
Infantile Isolated Absence of Right Pulmonary Artery with an Absent Stump and No Collaterals
Authors: Patil Sumant , Ghoshbag Sayantan , Pillay Usha
Published: February 2021

Unilateral absence of pulmonary artery (UAPA) is a rare entity. Diagnosis is often incidental based on echocardiography (ECHO)/computed tomography (CT) findings done for a cardiac evaluation or recurrent pulmonary pathology not responding to conventional treatment. Childhood-onset symptoms are often rare, and most of these cases are reported in adulthood or postpuberty. Here, we present a 5-month-old child with an isolated absence of right pulmonary artery without even an arterial stump or collaterals. Treatment options depend on the severity of symptoms and anatomy of the abnormal vessels, and in some cases, patients get better, if not completely well with the available medical and surgical treatments.
Effect of Piperine in Combination with Gamma Radiation on A549 Cells
Authors: Shaheer Koniyan , Lakshmanan M. Divya
Published: February 2021

Background Lung cancer is a major constrain that increases mortality globally. Radiotherapy is one of the treatment modalities against lung cancer. A high dose of targeted radiation is required to achieve the treatment efficacy of cell killing. After radiotherapy, eventual tumor progression and therapy resistance are still a consequence of patient who undertakes nonsurgical radiation therapy. Piperine, a plant alkaloid, has been known to enhance the action of the anticancer drugs in various drug-resistant cancer cells. The aim of the current in vitro study was to study the effect of piperine on radiosensitizing property against A549 cells.

Methods In vitro radiosensitizing activity of piperine was elucidated on A549 cells using MTT (3-(4, 5-dimethylthiazol-2-yl)-25-diphenyltetrazolium bromide) assay. CompuSyn analysis was used to compute the combination index values to analyze the combinatory effect of piperine and radiation

Results and Conclusion We observed that piperine increased tumor cell killing in combination with the γ-radiation in vitro. However, further studies are warranted to understand the molecular mechanism of the radiosensitizing action of piperine.
Item Analysis of Multiple-Choice Questions in Pharmacology in an Indian Medical School
Authors: Adiga Manoor Narasimha Sachidananda , Acharya Swathi , Holla Rajendra
Published: February 2021

Introduction Student assessment by multiple-choice questions (MCQs) is an integral part of student evaluation in medicine. The medical teacher should be trained to construct an item with proper stem and valid options. Periodic item analyses will make the process of assessment more meaningful. Hence, we conducted the study to analyze MCQs (item analysis) tested on a batch of MBBS students in pharmacology in their three internal assessment examinations.

Methods The study was conducted in the Department of Pharmacology of a medical college in Mangaluru on 150 students. The MCQs of the three internal assessment examinations (20 each) respectively were analyzed. We analyzed each question for difficulty index (DI), discrimination index (DsI), and distracter efficacy or functionality and expressed the percentage results.

Results The DI was in an acceptable range of 60, 75, and 90%, respectively, in the three internal assessments. The percentage of “too difficult” questions was 10, 20, and 10% and the average DsI was 0.32 ± 0.04, 0.28 ± 0.02, and 0.26 ± 0.02, respectively. In the second and third internal assessments, 95% of questions had functional distracters, while in the first internal assessment, only 60% of questions had functional distracters.

Conclusion We conclude from our study that even though the items (MCQs) framed for the internal assessments were in the acceptable range of quality in terms of the parameters assessed, we must improve MCQ’s construction in selecting distracters in some topics.
The Use of an Inanimate Simulation Model for the Correction of an Anorectal Malformation in the Training of Colorectal Pediatric Surgery
Authors: Joosten Maja , Bökkerink Guus M. J. , Levitt Marc A. , Diefenbach Karen A. , Reck Carlos A. , Krois Wilfried , de Blaauw Ivo , Botden Sanne M.B.I.
Published: February 2021

Introduction An anorectal malformation (ARM) is a congenital malformation that requires surgical correction. To acquire the skills needed to perform this complex procedure, an affordable simulation model has previously been developed and validated. The aim of this study is to evaluate the suitability of this ARM model (with perineal fistula) for training in hands-on workshops.

Materials and Methods The ARM model consists of a wooden casing with disposable perineal body. Participants in several international pediatric colorectal hands-on workshops in 2019 and 2020 were asked to participate. They were divided in a target group and an experienced group based on experience. All practiced the posterior sagittal anorectoplasty procedure on the model with multimodality guidance. Subsequently, statements on the suitability of the model for use during hands-on workshops were scored on a 5-point Likert scale.

Results A total of 80 participants were included (43 surgical specialists, 13 pediatric surgery fellows, and 25 residents). Nearly, all statements scored at least a mean of >4.0, all scored significantly better than a neutral opinion. The target group (n = 58) scored higher compared with the experienced group (n = 22) on “transferability of the skills to the clinical setting” (means 4.4 vs. 4.0, p = 0.038); however, the “suitability as a replacement for an animal model” scored significantly lower (means 3.6 vs. 3.9, p = 0.049). No other differences were found.

Conclusion This affordable ARM model was regarded a suitable model for training during preclinical hands-on workshops and could be used for the specified steps of the procedure.
Applying the Rasch model to analyze the effectiveness of education reform in order to decrease computer science students’ dropout
Authors: Takács Rita , Kárász Judit T. , Takács Szabolcs , Horváth Zoltán , Oláh Attila
Published: February 2021

Attrition is an important issue in higher education, especially in the field of computer science (CS). Here, we investigate to what extent an education reform affects the attrition of students by analyzing the pattern of grades of CS students’ academic achievement from 2010 to 2018 by IRT, based on Rasch-model analysis. We analyze data from 3673 undergraduate students of a large public university. In 2016 an education reform—as an intervention—was added to our BSc program: all theoretical lectures became compulsory to attend and we introduced a learning methodology course for all first-year students. According to our results, after the education reform most subjects became accomplishable, and students with lower levels of ability also tried to take exams. We succeeded in retaining 28% of our students. Analyzing students’ results could help administrators develop new programs in order to increase retention.
Simple, efficient nanoparticle synthesis technique uses pulsed underwater spark discharge
Authors: Ishimaru Matthew
Published: February 2021

High throughput method relies on a handful of readily available components and produces a large number of homogeneous nanoparticles in solution.
Quantum algorithmic randomness
Authors: Bhojraj Tejas
Published: February 2021

Quantum Martin-Löf randomness (q-MLR) for infinite qubit sequences was introduced by Nies and Scholz [J. Math. Phys. 60(9), 092201 (2019)]. We define a notion of quantum Solovay randomness, which is equivalent to q-MLR. The proof of this goes through a purely linear algebraic result about approximating density matrices by subspaces. We then show that random states form a convex set. Martin-Löf absolute continuity is shown to be a special case of q-MLR. Quantum Schnorr randomness is introduced. A quantum analog of the law of large numbers is shown to hold for quantum Schnorr random states.
Development of a compact X-band linear accelerator system mounted on an O-arm rotating gantry for radiation therapy
Authors: Kim Sanghoon , Lee Yong-Seok , Kim Geun-Ju , Lee Jeong-Hun , Kim Insoo S. , Shin Ki Young , Seol Yunji , Oh Youngah , Kang Young-Nam , Hwang Jinho , Shin Jin-Sol , Kim Aeran , Kim Jina , Kim Jung-Il
Published: February 2021

A compact X-band linear accelerator (LINAC) system equipped with a small and lightweight magnetron was constructed to develop a high-precision image-guided radiotherapy system. The developed LINAC system was installed in an O-ring gantry where cone-beam computed tomography (CBCT) was embedded. When the O-arm gantry is rotated, an x-ray beam is stably generated, which resulted from the stable transmission of radio frequency power into the X-band LINAC system. Quality assurance (QA) tests, including mechanical and dosimetry checks, were carried out to ensure safety and operation performance according to the American Association of Physicists in Medicine’s TG-51, 142, an international standard protocol established by accredited institutions. In addition, delivery QA of the radiotherapy planning system was conducted to verify intensity-modulated radiotherapy techniques. Therefore, it was demonstrated that the developed X-band LINAC system mounted on the O-arm gantry proved to be valid and reliable for potential use in CBCT image-guided radiation therapy.
Analysis of impedance matching for a spherical multi-degree-of-freedom ultrasonic motor
Authors: Li Zheng , Wang Zhe , Han Haitao , Sun Hexu
Published: February 2021

A novel spherical multi-degree-of-freedom ultrasonic motor is designed, which can achieve three-degree-of-freedom motion through the cooperative drive of three built-in traveling wave stators. The novel ultrasonic motor has the characteristics of compact structure and high power density. Additionally, in order to solve the problem of impedance mismatch between the ultrasonic motor and the driving power supply, a semi-analytical method of impedance matching based on parallel resonance is proposed according to the impedance characteristics of ultrasonic motor. Through the combination of theoretical derivation and finite element simulation, the ultrasonic motor impedance matching on the impedance circle is analyzed. By this method, the optimum matching inductor of the motor is determined. After matching, the motor obtains a larger vibration amplitude and higher transmission efficiency. Finally, the reliability of the method is verified by simulation and experiment, which provides a reference for further improving the motor performance.
Modeling solvation effects on absorption and fluorescence spectra of indole in aqueous solution
Authors: Abou-Hatab Salsabil , Carnevale Vincenzo , Matsika Spiridoula
Published: February 2021

Modeling the optical spectra of molecules in solution presents a challenge, so it is important to understand which of the solvation effects (i.e., electrostatics, mutual polarization, and hydrogen bonding interactions between solute and solvent molecules) are crucial in reproducing the various features of the absorption and fluorescence spectra and to identify a sufficient theoretical model that accurately captures these effects with minimal computational cost. In this study, we use various implicit and explicit solvation models, such as molecular dynamics coupled with non-polarizable and polarizable force fields, as well as Car–Parrinello molecular dynamics, to model the absorption and fluorescence spectra of indole in aqueous solution. The excited states are computed using the equation of motion coupled cluster with single and double excitations combined with the effective fragment potential to represent water molecules, which we found to be a computationally efficient approach for modeling large solute–solvent clusters at a high level of quantum theory. We find that modeling mutual polarization, compared to other solvation effects, is a dominating factor for accurately reproducing the position of the peaks and spectral line shape of the absorption spectrum of indole in solution. We present an in-depth analysis of the influence that different solvation models have on the electronic excited states responsible for the features of the absorption spectra. Modeling fluorescence is more challenging since it is hard to reproduce even the correct emitting state, and force field parameters need to be re-evaluated.
Automated fragmentation quantum mechanical calculation of 13C and 1H chemical shifts in molecular crystals
Authors: Shi Man , Jin Xinsheng , Wan Zheng , He Xiao
Published: February 2021

In this work, the automated fragmentation quantum mechanics/molecular mechanics (AF-QM/MM) approach was applied to calculate the 13C and 1H nuclear magnetic resonance (NMR) chemical shifts in molecular crystals. Two benchmark sets of molecular crystals were selected to calculate the NMR chemical shifts. Systematic investigation was conducted to examine the convergence of AF-QM/MM calculations and the impact of various density functionals with different basis sets on the NMR chemical shift prediction. The result demonstrates that the calculated NMR chemical shifts are close to convergence when the distance threshold for the QM region is larger than 3.5 Å. For 13C chemical shift calculations, the mPW1PW91 functional is the best density functional among the functionals chosen in this study (namely, B3LYP, B3PW91, M06-2X, M06-L, mPW1PW91, OB98, and OPBE), while the OB98 functional is more suitable for the 1H NMR chemical shift prediction of molecular crystals. Moreover, with the B3LYP functional, at least a triple-ζ basis set should be utilized to accurately reproduce the experimental 13C and 1H chemical shifts. The employment of diffuse basis functions will further improve the accuracy for 13C chemical shift calculations, but not for the 1H chemical shift prediction. We further proposed a fragmentation scheme of dividing the central molecule into smaller fragments. By comparing with the results of the fragmentation scheme using the entire central molecule as the core region, the AF-QM/MM calculations with the fragmented central molecule can not only achieve accurate results but also reduce the computational cost. Therefore, the AF-QM/MM approach is capable of predicting the 13C and 1H NMR chemical shifts for molecular crystals accurately and effectively, and could be utilized for dealing with more complex periodic systems such as macromolecular polymers and biomacromolecules. The AF-QM/MM program for molecular crystals is available at https://github.com/shiman1995/NMR.
Magnetically induced charge redistribution in the bending of a composite beam with flexoelectric semiconductor and piezomagnetic dielectric layers
Authors: Qu Yilin , Jin Feng , Yang Jiashi
Published: February 2021

We study electromechanical fields in a thin composite beam of a flexoelectric semiconductor layer sandwiched between two piezomagnetic dielectric layers induced by an applied magnetic field. The macroscopic theory of piezomagnetics and flexoelectric semiconductors is used. A one-dimensional model is derived from the three-dimensional equations. Responses under static and time-harmonic magnetic fields are obtained analytically from the model. Results show magnetically induced bending deformation and redistribution or motion of charge carriers toward the top and bottom of the beam through combined piezomagnetic and flexoelectric couplings. A coupling coefficient depending on the physical and geometric parameters of the structure is introduced to characterize the strength of the effect. The coupling coefficient assumes a maximum for a specific thickness ratio of the piezomagnetic and semiconductor layers. The results are fundamental to the emerging field of flexoelectronics when magnetic fields are involved.
r2SCAN-3c: A “Swiss army knife” composite electronic-structure method
Authors: Grimme Stefan , Hansen Andreas , Ehlert Sebastian , Mewes Jan-Michael
Published: February 2021

The recently proposed r2SCAN meta-generalized-gradient approximation (mGGA) of Furness and co-workers is used to construct an efficient composite electronic-structure method termed r2SCAN-3c. To this end, the unaltered r2SCAN functional is combined with a tailor-made triple-ζ Gaussian atomic orbital basis set as well as with refitted D4 and geometrical counter-poise corrections for London-dispersion and basis set superposition error. The performance of the new method is evaluated for the GMTKN55 database covering large parts of chemical space with about 1500 data points, as well as additional benchmarks for non-covalent interactions, organometallic reactions, and lattice energies of organic molecules and ices, as well as for the adsorption on polar salt and non-polar coinage-metal surfaces. These comprehensive tests reveal a spectacular performance and robustness of r2SCAN-3c: It by far surpasses its predecessor B97-3c at only twice the cost and provides one of the best results of all semi-local density-functional theory (DFT)/QZ methods ever tested for the GMTKN55 database at one-tenth of the cost. Specifically, for reaction and conformational energies as well as non-covalent interactions, it outperforms prominent hybrid-DFT/QZ approaches at two to three orders of magnitude lower cost. Perhaps, the most relevant remaining issue of r2SCAN-3c is self-interaction error (SIE), owing to its mGGA nature. However, SIE is slightly reduced compared to other (m)GGAs, as is demonstrated in two examples. After all, this remarkably efficient and robust method is chosen as our new group default, replacing previous composite DFT and partially even expensive high-level methods in most standard applications for systems with up to several hundreds of atoms.
Functional rarity and evenness are key facets of biodiversity to boost multifunctionality
Authors: Le Bagousse-Pinguet Yoann , Gross Nicolas , Saiz Hugo , Maestre Fernando T. , Ruiz Sonia , Dacal Marina , Asensio Sergio , Ochoa Victoria , Gozalo Beatriz , Cornelissen Johannes H. C. , Deschamps Lucas , García Carlos , Maire Vincent , Milla Rubén , Salinas Norma , Wang Juntao , Singh Brajesh K. , García-Palacios Pablo
Published: February 2021

Significance

Identifying species assemblages that boost the provision of multiple ecosystem functions simultaneously (multifunctionality) is crucial to undertake effective restoration actions aiming at simultaneously promoting biodiversity and high multifunctionality in a changing world. By disentangling the effect of multiple traits on multifunctionality in a litter decomposition experiment, we show that it is possible to identify the assemblages that boost multifunctionality across multiple species mixtures originating from six biomes. We found that higher evenness among dissimilar species and the functional attributes of rare species as key biodiversity attributes to enhance multifunctionality and to reduce the abundance of plant pathogens. Our study identifies those species assemblages needed to simultaneously maximize multifunctionality and limit plant disease risks in natural and managed ecosystems.
“Join the Army. Become the Power of China”
Authors: Sun Yi , Zhang Mi , Chen Lang
Published: February 2021

Military recruitment advertising, as a type of authoritative political video advertisement, demonstrates a country’s military culture. This paper will provide a brand-new perspective in researching Chinese military culture from the approach of multimodal metaphor. Currently, a multimodal analysis of military recruitment advertising in terms of short video clips does not exist, and most of the existing multimodal studies have focused on Western mainstream media, whereas media with Chinese characteristics have remained mostly untouched by research. WithForceville and Urios-Aparisi’s (2009)Multimodal Metaphor Theory (MMT) as a theoretical basis, and the newly-released recruitment advertising “The Power of China” as the research object, this paper utilizes the MIPVU and ELAN image tagging software to identify and analyze the multimodal metaphors in “The Power of China” under the framework of MMT.
αβγδ T cells play a vital role in fetal human skin development and immunity
Authors: Reitermaier René , Krausgruber Thomas , Fortelny Nikolaus , Ayub Tanya , Vieyra-Garcia Pablo Augusto , Kienzl Philip , Wolf Peter , Scharrer Anke , Fiala Christian , Kölz Marita , Hiess Manuela , Vierhapper Martin , Schuster Christopher , Spittler Andreas , Worda Christof , Weninger Wolfgang , Bock Christoph , Eppel Wolfgang , Elbe-Bürger Adelheid
Published: February 2021

T cells in human skin play an important role in the immune defense against pathogens and tumors. T cells are present already in fetal skin, where little is known about their cellular phenotype and biological function. Using single-cell analyses, we identified a naive T cell population expressing αβ and γδ T cell receptors (TCRs) that was enriched in fetal skin and intestine but not detected in other fetal organs and peripheral blood. TCR sequencing data revealed that double-positive (DP) αβγδ T cells displayed little overlap of CDR3 sequences with single-positive αβ T cells. Gene signatures, cytokine profiles and in silico receptor–ligand interaction studies indicate their contribution to early skin development. DP αβγδ T cells were phosphoantigen responsive, suggesting their participation in the protection of the fetus against pathogens in intrauterine infections. Together, our analyses unveil a unique cutaneous T cell type within the native skin microenvironment and point to fundamental differences in the immune surveillance between fetal and adult human skin.
Future attractors of Bianchi types II and V cosmologies with massless Vlasov matter
Authors: Barzegar Hamed
Published: February 2021

It is shown that the generalized Collins–Stewart radiation and Milne solutions are attractors of the massless Einstein–Vlasov system for Bianchi types II and V spacetimes, respectively. The proof is based on an energy method and bootstrap argument which are used to determine the decay rates of the perturbations away from the attractors.
Adhesion of Flk1-expressing cells under shear flow in phospholipid polymer-coated immunoaffinity channels
Authors: Otaka Akihisa , Mahara Atsushi , Ishihara Kazuhiko , Yamaoka Tetsuji
Published: February 2021

Label-free cell separation is a promising method in the field of stem-cell research to obtain desired cell populations. Here, we report on phospholipid polymer-coated microfluidic channels with immobilized antibodies as devices for the capture of cells expressing target antigens in a label-free manner. We fabricated a microfluidic channel containing immobilized antibodies against vascular endothelial growth factor receptor 2 (Flk1), a potential marker for cardiac, angiogenic, and hematopoietic cell regeneration. A series of investigations was carried out to elucidate the effect of the immobilized antibodies on the adhesion behavior of the Flk1-expressing cell subpopulation derived from induced pluripotent stem cells. Increasing the immobilized antibody density (0.18–5.0 × 109 ligands mm−2) led to an increased number of cells adhering to the channel. The antibody-immobilized polymer-coated surface suppressed nonspecific cell adhesion, which was swept away by a weak shear flow, and captured Flk1-expressing cells under a wall shear stress of 1.7 Pa. Flk1 expression was 2.8-fold higher in the cells that adhered than in those that did not adhere. Therefore, an optimal antibody density and sweeping flow are required for effective label-free separation of Flk1-positive cells.
Extremely large linear magnetoresistance in antimony crystal
Authors: Dasoundhi Mukesh Kumar , Rajput Indu , Kumar Devendra , Lakhani Archana
Published: February 2021

In this article, we report the observation of extremely large non-saturating linear magnetoresistance (MR) in antimony (Sb) crystal. An extremely large magnetoresistance of 43 000% at 2 K and large unsaturating MR ∼70% at room temperature is observed at the magnetic field of 9 T. Hall measurements reveal a very high mobility ∼3.8 × 104 cm2 V s−1 of charge carriers and strong temperature dependence of carrier concentration and mobility. The respective scaling of MR and crossover field (B 

c
) from quadratic to linear MR with mobility and inverse of mobility describes the classical origin of large linear MR in this crystal as suggested by Parish and Littlewood model for disordered systems.
A counter-current flow micro-packed-bed DBD plasmatron for the synthesis of a methylated cobaloxime
Authors: Liu Yukun , Sabio Jasmine C , Hartman Ryan L
Published: February 2021

An atmospheric, dielectric-barrier discharge µ-plasmatron was designed, fabricated, and applied to synthesize a methylated organometallic complex. The design comprises counter-current flow to packed-bed microstructures to facilitate gas–liquid and plasma–liquid mixing. Micropillars arranged in a staggered configuration served as a porous media for the optimum 2D mixing of components that replenish plasma-liquid interfaces. Longitudinal dispersion was characterized through residence time distribution (RTD) measurements. The experimental RTD data were then described by an axial dispersion model with a time delay parameter. Levenspiel number (lv) indicating the intensity of axial dispersion was estimated in the range of 20.1–374, indicating that a dispersion model should be accounted for in plasma-assisted reaction kinetics development. Stable plasma excitation of methane-helium gas mixtures was observed within the 2D porous media, by in-situ optical emission spectra, while applying an alternating high voltage across the dielectric barrier. This novel technique made it possible to confirm in-situ formations of methyl radicals. Interestingly, the porous media served as a static mixer as no discrete plasma streamers were observed. To investigate its utility, an example homogeneous cobalt catalyst was injected into the µ-plasmatron and methylated. Our findings potentially introduce a new plasma-assisted reactor design and methodology for the synthesis of methylated cobaloxime.
Temperature and band gap dependence of GaAsBi p-i-n diode current–voltage behaviour
Authors: Richards R D , Harun F , Nawawi M R M , Liu Y , Rockett T B O , David J P R
Published: February 2021

The dark current characteristics of two series of bulk GaAsBi p-i-n diodes are analysed as functions of temperature and band gap. Each temperature dependent measurement indicates that recombination current dominates in these devices. The band gap dependence of the dark currents is also consistent with recombination dominated current for the devices grown at a common growth temperature, indicating that the presence of Bi does not directly adversely affect the dark currents. However, the devices grown at different growth temperatures exhibit a faster increase in dark current with decreasing device band gap, suggesting that a reduced growth temperature causes a reduction in minority carrier lifetime.
Multicritical points in a model for 5f-electron systems under pressure and magnetic field
Authors: Faúndez Julián , Magalhães S G , Calegari E J , Riseborough P S
Published: February 2021

We investigate the evolution of multicritical points under pressure and magnetic field in a model described by two 5f bands (called α and β) that hybridize with a single itinerant conduction band. The interaction is given by the direct Coulomb and the Hund’s rule exchange terms. Three types of orderings are considered: two conventional spin density waves (SDWs) and an exotic SDW, i.e., with no magnetic moment formation. The conventional SDWs phases, are characterized by

m

f

β

>

m

f

α

and

m

f

α

>

m

f

β

, respectively, where

m

f

α

and

m

f

β

are the intraband staggered magnetizations. The exotic SDW, which has time reversal symmetry, is described by a purely imaginary order parameter. This phase is related to a band mixing given by the spin-flip part of the Hund’s rule exchange interaction. As result, without magnetic field, the phase diagrams of temperature (T) versus pressure (given by the variation of the bandwidth (W)) shows a sequence of phase transitions involving the three phases which gives rise to multicritical points. The presence of the magnetic field (h

z
) has drastic effects on part of the phase diagram and the location of the multicritical points.