bluuebunny/crossref_metadata_2025 huggingface dataset:
Fault‐tolerant control strategy with reduced switching frequency for inverter‐based fault in open‐winding PMSM system
Authors: Lv Kangfei , Dong Xiwei , Liu Lili , Nian Heng
Published: February 2020

The open‐winding permanent magnet synchronous machine (OW‐PMSM) system is widely investigated for its potential fault tolerance while extra switching loss is inevitable due to the doubled switch devices. Hence, to further improve its performance, a fault‐tolerant control strategy against the inverter‐based fault, in which the corresponding terminal of the phase winding is connected with the mid‐point of the two capacitances in parallel to the dc voltage, is proposed in this Letter. In the proposed method, the reference voltages are modulated under the three‐phase stationary coordinate system, considering the voltage fluctuation of the capacitances. In addition, to reduce the switching frequency, the reference voltages are adjusted synchronously, according to the polarity of the reference voltages. Moreover, the effective modulation range of the proposed method is analysed. Finally, the performance of the proposed strategy is validated experimentally.
Optimal bit allocation scheme for distributed detection system with imperfect channels
Authors: Luo Junhai , He Xiaoting
Published: February 2020

There are two main classes of decision fusion methods, namely hard decision fusion (HD) and soft decision fusion (SD), in which the number of bits transmitted by each local sensor to the fusion centre (FC) is always same, namely one bit in HD and n (n ≥ 2) bits in SD. However, considering that there is always a limit of bandwidth in a distributed detection system, the number of bits sent by each local sensor to the FC does not need to be the same and should be allocated reasonably and suitably. Therefore, this study proposes an optimal bit allocation scheme based on the memetic algorithm, in which the number of bits transmitted by each local sensor could be different. This scheme aims to maximise the detection probability under the limit of bandwidth for a detection system with imperfect channels. The overall detection probability objective function about the number of allocated bits is derived. To optimise this objective function, an improved memetic algorithm with two local adjustment strategies, namely non‐elite learning local adjustment optimisation strategy and elite greedy local adjustment optimisation strategy, is proposed to allocate the optimal number of bits. Simulation results show the efficiency and effectiveness of the proposed scheme.
Survey on WiFi‐based indoor positioning techniques
Authors: Liu Fen , Liu Jing , Yin Yuqing , Wang Wenhan , Hu Donghai , Chen Pengpeng , Niu Qiang
Published: February 2020

With the rapid development of wireless communication technology, various indoor location‐based services (ILBSs) have gradually penetrated into daily life. Although many other methods have been proposed to be applied to ILBS in the past decade, WiFi‐based positioning techniques with a wide range of infrastructure have attracted attention in the field of wireless transmission. In this survey, the authors divide WiFi‐based indoor positioning techniques into the active positioning technique and the passive positioning technique based on whether the target carries certain devices. After reviewing a large number of excellent papers in the related field, the authors make a detailed summary of these two types of positioning techniques. In addition, they also analyse the challenges and future development trends in the current technological environment.
VLTI-PIONIER imaging of the red supergiant V602 Carinae
Authors: Climent J. B. , Wittkowski M. , Chiavassa A. , Baron F. , Marcaide J. M. , Guirado J. C. , Freytag B. , Höfner S. , Haubois X. , Woillez J.
Published: February 2020

Context. Red supergiant stars possess surface features and extended molecular atmospheres. Photospheric convection may be a crucial factor of the levitation of the outer atmospheric layers. However, the mechanism responsible is still poorly understood.

Aims. We image the stellar surface of V602 Carinae (V602 Car) to constrain the morphology and contrast of the surface features and of the extended atmospheric layers.

Methods. We observed V602 Car with the Very Large Telescope Interferometer PIONIER instrument (1.53–1.78 μm) between May and July 2016, and April and July 2019 with different telescope configurations. We compared the image reconstructions with 81 temporal snapshots of 3D radiative-hydrodynamics (RHD) CO5BOLD simulations in terms of contrast and morphology, using the Structural Similarity Index.

Results. The interferometric data are compatible with an overall spherical disk of angular diameter 4.4 ± 0.2 mas, and an extended molecular layer. In 2016, the reconstructed image reveals a bright arc-like feature toward the northern rim of the photospheric surface. In 2019, an arc-like feature is seen at a different orientation and a new peak of emission is detected on the opposite side. The contrasts of the reconstructed surface images are 11% ± 2% and 9% ± 2% for 2016 and 2019, respectively. The morphology and contrast of the two images are consistent with 3D RHD simulations, within our achieved spatial resolution and dynamic range. The extended molecular layer contributes 10–13% of the total flux with an angular diameter of 6–8 mas. It is present but not clearly visible in the reconstructed images because it is close to the limits of the achieved dynamic range. The presence of the molecular layer is not reproduced by the 3D RHD simulations.

Conclusions. 3D RHD simulations predict substructures similar to the observed surface features of V602 Car at two different epochs. We interpret the structure on the stellar surface as being related to instationary convection. This structure is further convolved to larger observed patches on the stellar surface with our observational spatial resolution. Even though the simulations reproduce the observed features on the stellar surface, convection alone may not be the only relevant process that is levitating the atmosphere.
Case study of industrial symbiosis for improved residual material utilisation in the steel industry
Authors: Lundkvist Katarina , Rosendahl Sara , Sandberg Erik , Haase Björn , Stemne Jeanette , Peltola Pasi , Eriksson Robert
Published: February 2020

Steel production is a material and energy intensive industry which, in addition to steel products, generates residual materials such as metallurgical slag, dust and sludge. These residual materials are recycled and used to a great extent as well in-house as for external purposes. Even so, some materials are currently landfilled due to difficulties in finding use or recycling possibilities. This applies, for example, to zinc-containing sludge and dust from ore-based steel production and certain iron-rich, lime and carbon-containing materials from scrap-based steel production. A case study has been performed with the aim to develop a methodology for evaluating industrial symbiosis possibilities in regard to increased material efficiency in steel production systems. The methodology is based on system analysis of steel production routes in combination with economical assessment of hypothetical business concepts by using residual materials from one industry as secondary raw materials in another. The paper presents case study results and indicates how this methodology could be applied to maximise the residual materials utilisation. By the methodology discussed and with a circular-economic perspective, it is shown that high economic potential for one material could be used to increase the utilisation of other materials with lower economic potential.
Establishing an industrial symbiosis – key factors and time aspects in steel industry
Authors: Rosendahl Sara , Lundkvist Katarina , Haase Björn , Stemne Jeanette , Andersson Linn , Eriksson Robert
Published: February 2020

Today production industry has increasing incentives to be resource efficient and sustainable. Many residual material streams from production processes are therefore recycled internally; however, some streams might be of better use in another industry. In this study, factors seen as encouraging and/or barriers in the work towards an industrial symbiosis with residual materials, between two or more industries, were identified. The factors were divided into five categories: physical/technical, regulatory, business, motivation and society, on three organisational levels. Based on the key factors, the time aspect for establishing an industrial symbiosis was studied and criteria that need to be met in order to carry on with a business idea for a residual material were divided into three work phases. The study shows that an industrial symbiosis based on residual materials on many levels differs from a business with main products, for example when it comes to laws and policies. With residual materials it is also extra important to have good understanding of the material properties and the customer’s material requirements. It was concluded that the establishment of industrial symbioses would be facilitated if all materials had the same conditions regardless of origin provided that the final product gets the same properties.
Vieillissement de l’occlusion dentaire
Authors: D’Incau Emmanuel , Rouzé l’Alzit François , Decaup Pierre-Hadrien , Soenen Arnaud
Published: February 2020

La mise au point de mesures préventives et curatives efficaces passe par la connaissance du vieillissement des organes et de leurs fonctions. Ce principe s’applique à l’occlusion dentaire dont il est important de connaître le vieillissement. L’objectif principal de cet article est de revenir, sous forme de revue narrative, sur cette problématique d’abord dans un contexte physiologique puis dans un contexte pathologique.
Chirurgie Orthognathique des patients séniors : repoussons les limites
Authors: Charrier Jean-Baptiste
Published: February 2020

Le patient sénior tel qu’il est défini dans les modalités de cette monographie est âgé de 55 à 75 ans.

La chirurgie orthognathique s’est considérablement développée ces dernières années. Les techniques chirurgicales, les techniques d’anesthésie, le matériel d’ostéosynthèse, la prise en charge orthodontique et les capacités de réhabilitation parodontales et implanto-portées se sont fortement améliorées et ont permis un développement de cette chirurgie avec un élargissement remarquable, tant concernant les indications que la tranche d’âge de patients susceptibles de bénéficier de ce type de chirurgie.

Dans cet article nous définissons les modalités, avantages et inconvénients spécifiques, inhérents à la prise en charge d’un patient sénior.

L’accent est mis sur les dimensions physiologique, psychologique et esthétique, dont il faut tout particulièrement tenir compte pour optimiser cette chirurgie.
Using multiflow formulations to solve the Steiner tree problem in graphs
Authors: Bahiense Laura , Besso Arthur , Tostas Rogerio , Maculan Nelson
Published: February 2020

We present three different mixed integer linear models with a polynomial number of variables and constraints for the Steiner tree problem in graphs. The linear relaxations of these models are compared to show that a good (strong) linear relaxation can be a good approximation for the problem. We present computational results for the STP OR-Library (J.E. Beasley) instances of type b, c, d and e.
Weniger Stürze unter Teriparatid in Patienten mit Osteoporose: Eine Meta-Analyse
Authors: Möckel Luis
Published: February 2020

Einleitung Da Stürze ein Risikofaktor für Frakturen sind, war das Ziel dieser Meta-Analyse, den Effekt von Teriparatid auf das Sturzrisiko bei Patienten mit Osteoporose zu bewerten.

Methoden Eine systematische Suche nach randomisierten, klinischen Studien mit Teriparatid wurde in Pubmed und der Datenbank clinicaltrials.gov durchgeführt. Entsprechend der Einschlusskriterien geeignete Studien wurden für die Meta-Analyse verwendet und Odds Ratios (OR) sowie die dazugehörigen 95 %-Konfidenzintervalle (95 %-KI) berechnet.

Ergebnisse Es wurden neun Studien mit 5.822 Patienten identifiziert und in diese Meta-Analyse eingeschlossen. Die Analyse zeigte, dass Patienten unter Teriparatid ein statistisch signifikant geringeres Risiko für einen Sturz hatten als Patienten in der Kontrollgruppe (OR: 0,75; 95 % KI: 0,56–1,00; p = 0,05; n = 5.822). Gegenüber einer reinen Bisphosphonat-Kontrollgruppe zeigte Teriparatid eine nichtsignifikante Reduktion des Sturzrisikos (OR: 0,77; 95 % KI: 0,55–1,06; p = 0,11; n = 2.658).

Schlussfolgerung Teriparatid senkte in dieser Meta-Analyse das Sturzrisiko signifikant gegenüber der Kontrollgruppe und könnte somit bei Patienten mit Osteoporose und hohem Sturzrisiko vorteilhaft sein.
Clostridium difficile Infection: An Epidemiology Update
Authors: De Roo Ana C. , Regenbogen Scott E.
Published: February 2020

Clostridium (reclassified as “Clostridioides”) difficile infection (CDI) is a healthcare-associated infection and significant source of potentially preventable morbidity, recurrence, and death, particularly among hospitalized older adults. Additional risk factors include antibiotic use and severe underlying illness. The increasing prevalence of community-associated CDI is gaining recognition as a novel source of morbidity in previously healthy patients. Even after recovery from initial infection, patients remain at risk for recurrence or reinfection with a new strain. Some pharmaco-epidemiologic studies have suggested an increased risk associated with proton pump inhibitors and protective effect from statins, but these findings have not been uniformly reproduced in all studies. Certain ribotypes of C. difficile, including the BI/NAP1/027, 106, and 018, are associated with increased antibiotic resistance and potential for higher morbidity and mortality. CDI remains a high-morbidity healthcare-associated infection, and better understanding of ribotypes and medication risk factors could help to target treatment, particularly for patients with high recurrence risk.
Fecal Microbiota Transplantation: Redefining Surgical Management of Refractory Clostridium difficile Infection
Authors: Cheng Yao-Wen , Fischer Monika
Published: February 2020

Fecal microbiota transplantation (FMT) is the process of transplanting stool from a healthy donor into the gut of a diseased individual for therapeutic purposes. It has a clearly defined role in the treatment of recurrent Clostridium difficile (reclassified as “Clostridioides difficile”) infection (CDI), with cure rates over 90% and decreased rates of subsequent recurrence compared with anti-CDI antibiotics. There is emerging evidence that FMT is also effective in the treatment of severe and fulminant CDI, with associated decreases in mortality and colectomy rates compared with standard antibiotic therapy. FMT shows promise as salvage therapy for critically-ill CDI patients refractory to maximum medical therapy and not deemed to be surgical candidates. FMT should be considered early in the course of severe CDI and should be delivered immediately in patients with signs of refractory CDI. Expansion of FMT's use along the spectrum of CDI severity has potential to decrease associated rates of mortality and colectomy.
Mutation in KCNJ2 Gene in a Boy with Atypical Features of Andersen–Tawil Syndrome, ADHD, and ASD: An Expanding Phenotype
Authors: Fadilah Ala , Mordekar Santosh R. , Matthai Sona
Published: February 2020

Andersen–Tawil syndrome, a potassium ion channelopathy, is caused by mutations in the KCNJ2 gene, and accounts for approximately 10% of channelopathies. Phenotype is variable. An 11-year-old boy presented with periodic paralysis without localizing neurological signs, associated in only two of three occasions with hypokalemia, on a background of a diagnosis of attention deficit hyperactivity disorder and autism spectrum disorder. There was a history of syncope and palpitations. This was a matter of diagnostic uncertainty due to the difficulty in interpreting his neurological signs, and inconsistency of abnormal potassium levels. In children/young people with recurrent episodes of weakness without localizing signs on physical examination, and syncope, the possibility of a channelopathy should be considered, even in the absence of serum electrolyte abnormalities. There is a possible link between KCNJ2 mutations and difficulties in attention and a specific neurocognitive profile.
Surgical Outcomes, Complications, and Long-Term Functionality for Free Vascularized Fibula Grafts in the Pediatric Population: A 17-Year Experience and Systematic Review of the Literature
Authors: McCullough Meghan C. , Arkader Alexandre , Ariani Rojine , Lightdale-Miric Nina , Tolo Vernon , Stevanovic Milan
Published: February 2020

Background In the pediatric population, bony defects of the extremities pose a significant challenge for which free vascularized fibular grafts (FVFGs) represent a valuable reconstructive option. The purpose of this study was to explore surgical outcomes, complications, and long-term functionality of FVFG for this patient group.

Methods Using MEDLINE and PubMed databases, studies were identified of pediatric extremity reconstruction using FVFG which reported functional outcomes and/or complications. The operative logs at a tertiary pediatric center were then reviewed for cases of FVFG between January 2000 and 2017. Demographic characteristics, surgical indications, operative details, graft survival, bony union, complications, and functionality of the reconstruction were recorded.

Results A total of 366 studies were identified with 23 ultimately meeting inclusion criteria in the systematic review. In the institutional series, 29 patients were included with mean age of 9.7 years (1–17 years). Indications for reconstruction included malignant bone tumor (n = 11), osteomyelitis (n = 9), congenital pseudoarthrosis (n = 6), and osteofibrous dysplasia (n = 3). Major postoperative complications included graft nonunion (24.1%), fracture (17.2%), and hardware failure (17.2%). Thirteen patients (44.8%) experienced delayed complications, while two (6.8%) experienced an immediate complication. Complications occurred in the donor site in 2 cases and the recipient site in all 13 cases. Long-term graft survival was achieved in 27 patients (93.1%), and 23 (79.3%) had full functional recovery, with an average Musculoskeletal Tumor Society score of 90% (60–100%). Mean follow-up was 5.17 years (2–12 years).

Conclusion This review and institutional series demonstrate the versatility of FVFG to facilitate limb reconstruction in large defects or serve as a salvage option in complex cases. While immediate and donor-site complications are uncommon, delayed recipient-site complications are frequent, and patients and families should be counseled regarding this expectation. Though technically challenging, excellent long-term graft viability and functional recovery can be achieved in the large majority of patients.
Evaluation of Sensation on Mastectomy Skin Flaps following Immediate Breast Reconstruction
Authors: Akdeniz Dogan Zeynep , Farhadi Jian
Published: February 2020

Background During a subcutaneous mastectomy, nerves are severed and patients lose sensation on the breast skin. The aim of this study is to investigate factors that have impact on the sensation of the mastectomy flaps and patients' own perception regarding overall breast skin sensation.

Patients and Methods Patients who have undergone skin sparing or nipple sparing mastectomy with immediate reconstruction with either an implant or autologous tissue were included. Sensory assessment was performed at least 12 months after surgery using Semmes–Weinstein monofilaments (Aesthesio, San Jose, CA). The breast envelope was divided into four quadrants, and one measurement from each quadrant was recorded. Patients were also asked to fill out a questionnaire before the examination.

Results A total of 59 breasts in 40 women were examined. In lower medial quadrant, significantly more patients reported “no sensation” in the radiated group than the nonradiated group. In upper medial quadrant and lower lateral quadrant, patients with NSM reported better sensation than patients with skin sparing mastectomy (SSM).

Conclusion Vascularized tissue did not improve sensory recovery. There was no relationship between sensation and the preoperative cup size and the number of revision surgeries. Irradiation was associated with higher sensory thresholds in lower medial quadrant. Nipple sparing mastectomy was associated with lower sensory thresholds in two quadrants compared to SSM. Independent of all variables none of the patients reported normal sensation.
Comparison of the ViOptix Intra.Ox Near Infrared Tissue Spectrometer and Indocyanine Green Angiography in a Porcine Bowel Model
Authors: Khavanin Nima , Almaazmi Hamda , Darrach Halley , Kraenzlin Franca , Safar Bashar , Sacks Justin M.
Published: February 2020

Background This study aims to directly compare measurements of tissue oxygenation obtained using the Intra.Ox (Vioptix Inc., Fremont, CA) near infrared spectrometer with the perfusion assessment of the indocyanine green (ICG)-based SPY Elite imaging system (Stryker Co., Kalamazoo, MI) in a porcine bowel model.

Methods Two live minipigs underwent laparotomy and isolation of a 30-cm segment of a large bowel. Standardized oximetry measurements were taken along the segment of bowel immediately before, after, and serially for 30 minutes following transection. A 0.5 mg/kg dose of ICG was then injected intravenously and the SPY Elite system was used to visualize and quantify tissue perfusion. Pearson's correlation coefficients were calculated using the outcomes.

Results Transected and ligated bowel yielded mean Intra.Ox measurements of 61% oxygenation at the proximal base of the limb and 27.8% at the distal edges. Analysis of the relative ICG fluorescence using the SPY Elite's proprietary software yielded perfusion estimates of 64.8% proximally and 6.8% distally. Intra.Ox and SPY Elite measurements demonstrate a Pearson product–moment correlation of 0.929. Repeat measurements at 15-mm intervals along the tissue yielded decreasing Intra.Ox measurements along the length of the flap that correlate to SPY Elite measurements (r = 0.645).

Conclusion Both the Intra.Ox and the SPY detected clinically relevant changes in bowel oxygenation following transection and ligation. The use of intravenous ICG dye did not appear to affect measurements of tissue oxygenation obtained using the Intra.Ox.
Obesity and the Abdominal Wall Vasculature: Correlating BMI with Perforator Anatomy
Authors: DelMauro Matthew A. , Moon Victor A.
Published: February 2020

Background Given the national trends in obesity, reconstructive surgeons are faced with an increasing number of overweight and obese women interested in postmastectomy breast reconstruction. While the link between obesity and adverse postoperative outcomes is well established, few studies have explored the relationship between body mass index (BMI) and the vasculature of the anterior abdominal wall.

Methods A radiographic review was conducted on female patients who underwent computed tomographic angiography (CTA) of the anterior abdominal wall. CTA studies were evaluated for perforator caliber and quantity. Patients were stratified by BMI. The relationship between BMI and the diameter and number of deep inferior epigastric artery (DIEA) perforators was analyzed using analysis of variance using Minitab software with α of 0.05.

Results There were a total of 916 hemiabdomens included in this study. There was no statistically significant correlation between BMI and DIEA diameter or mean diameter of major (≥ 1 mm) DIEA perforators. There was a statistically significant negative correlation between BMI and the number of major DIEA perforators (p < 0.01).

Conclusion Despite the increased demands of excess abdominal adiposity, DIEA perforator caliber was not correlated with BMI on CTA. The number of major DIEA perforators visualized on CTA decreased with increasing body weight may indicate a limitation of CTA for presurgical planning of abdominal free flaps in obese patients.
Persistent Left Superior Vena Cava Identified during Peripherally Inserted Central Catheter Line Placement
Authors: Borde Arvind , Ukirde Vivek
Published: February 2020

Introduction A persistent left superior vena cava (SVC) is found in 0.3 to 0.5% of the general population. It is seen in up to 10% of the patients with a congenital cardiac anomaly, being the most common thoracic venous anomaly, and is usually asymptomatic. Being familiar with such anomaly could help clinicians avoid complications during the placement of central lines, Swan-Ganz catheters, peripherally inserted central catheter (PICC) lines, dialysis catheters, defibrillators, and pacemakers.

Case Presentation We describe a case of persistent left SVC which was noted after placement of a PICC line. A 5-year-old male child was hospitalized for evaluation and management of leukemia. He required PICC line placement for chemotherapy. He was noted to have a persistent left SVC during the procedure under fluoroscopic guidance and subsequently correct placement of PICC line in right SVC.

Discussion This anatomical variant can pose iatrogenic risks if the clinician does not recognize it. A central catheter that tracks down the left mediastinal border may also be in the descending aorta, internal thoracic vein, superior intercostal vein, pericardiophrenic vein, pleura, pericardium, or mediastinum.

Conclusion Our case is significant because the patient was diagnosed with double SVC on table only followed by the placement of PICC line into the right SVC. This case strongly demonstrates the importance of knowing the thoracic venous anomalies.
Burning Bridges: The problem of relations in object-oriented ontology—a topological approach
Authors: Wilde Niels
Published: February 2020

This paper explores the status of relations in object-oriented ontology (OOO). On the one hand, objects often seem to get the upper hand, since what an object is cannot be reduced to the sum total of its (external) relations. On the other hand, there cannot be a hierarchy between object and relations, since we would then be talking about a vertical ontology, and what OOO advocates is a flat ontology. Relations must have the same ontological status as objects, due to the flatness of reality. Furthermore, relations already play a role in the things themselves in terms of an internal relationality. What an object is cannot be separated from where it is. In other words, the object is its where. While internal relations seem to work at the central core of objects, external relations pose the greatest problem. If objects are destructible, we have to re-evaluate the status of external relations. While OOO is still to develop a fully-fledged theory of destructibility or death, I suggest that Kierkegaard’s notion of finitude can provide a fruitful trajectory. With Kierkegaard, I argue that death cannot merely be located within an object but concerns the radical outside which brings the status of external relationality to the fore.
The phototransport in halide perovskites: From basic physics to applications
Authors: San Granit , Balberg Michal , Jedrzejewski Jedrzej , Balberg Isaac
Published: February 2020

There is at present an intensive, wide, and growing interest in the phototransport properties of Halide Perovskites (HaPs) that follows their recent discovery as promising materials for efficient and easy to fabricate solar cells. However, the basic physics of the exceptional superior performance of these cells is still a puzzle. In the present work, we suggest a solution to the puzzle and show that the exceptional performance of those cells is due to the special-rare scenario of shallow centers that dominate the recombination process in the HaPs (in addition to the obvious efficient light absorption). Our analysis provides a general new extension of the classical theory of phototransport and an elucidation of the physical essence of the operation of p-i-n solar cells. This extension is based on the Shockley–Read (SR) recombination model for the simple, single-level kind of recombination centers. In this article, we show that the latter understanding is very beneficial for future improvements in the design and fabrication of HaP-based solar cells, beyond their present configurations. In particular, we explain why and how various annealing procedures can improve the solar energy conversion of the corresponding solar cells. We further suggest that an all-perovskite-all-vacuum-deposited solar cell is feasible and promising for the upscaling of the HaPs cells' technology.
The effect of Co-doping on dielectric properties and bandgap of zinc silicate nanowires
Authors: Bharti Dhiraj Kumar , Verma Ketki , Srivastava Avanish Kumar , Gupta Manoj Kumar
Published: February 2020

In this study, pristine and cobalt (Co) doped zinc silicate (Zn2SiO4) nanowires were synthesized by a simple and cost-effective hydrothermal method. The average length and diameter of Zn2SiO4 nanowires were 1.0–1.5 μm and 40–60 nm, respectively, in electron microscopic studies. In the case of Co-doped Zn2SiO4 nanowires, average length and diameter increase to 4.0–5.0 μm and 70–90 nm, respectively, and a significant increase in particle size was observed. A dielectric constant measurement of pristine and Co-doped Zn2SiO4 nanowires was performed in the frequency range of 20 Hz–2 MHz. The dielectric constant of pristine and Co-doped Zn2SiO4 nanowires was found to be 212 and 1360 at a frequency of 20 Hz, respectively. Such dramatic enhancement in the dielectric constant (approximately six fold) of Co-doped Zn2SiO4 nanowires suggests that these nanowires are promising materials for applications in next generation charge storage devices. UV–Vis spectral analysis shows a remarkable reduction in the optical bandgap of Co-doped Zn2SiO4 nanowires as a result of doping. Such enhancement in the dielectric constant and reduction in the optical bandgap were discussed in light of doping and size enhancement.
Strain control of phase transition and magnetocaloric effect in Nd0.5Sr0.5MnO3 thin films
Authors: Liu Yao , Ma Tianyu , Qiao Kaiming , Li Jia , Xiao Andong , Wang Jing , Hu Fengxia , Shen Baogen
Published: February 2020

Phase transition and the magnetocaloric effect (MCE) in Nd0.5Sr0.5MnO3 (NSMO) epitaxial thin films were tailored through controlling the lattice-mismatch-induced-strain by depositing on (011)—(La0.18Sr0.82)(Al0.59Ta0.41)O3 and SrTiO3 (STO) single crystalline substrates, respectively. The NSMO film grown on STO, exhibiting uniaxial like tensile strain of 1.3% along the in-plane [100] direction, undergoes a paramagnetic to ferromagnetic transition at ∼210 K followed by a ferromagnetic to A-type antiferromagnetic transition at ∼179 K upon cooling; meanwhile, the film grown on LSAT, exhibiting anisotropic in-plane tensile strains of 0.36% along [100] and 0.50% along [01¯1] directions, undergoes further transition to CE-type antiferromagnetic transition at ∼145 K. NSMO/LSAT with such transitions facilitates a strong MCE over a much wider temperature range from 90 to 170 K, with the magnetic entropy change comparable to the recently reported La0.25Ca0.75MnO3 bulk. These findings suggest that control of strain in manganite films with first-order phase transition is a feasible way to broaden their MCE temperature range.
Dipole radiation near a reflecting corner
Authors: Arnoldus Henk F. , Xu Zhangjin , Li Xin
Published: February 2020

We consider a radiating electric dipole, located near the joint of two orthogonal mirrors. The field lines of energy flow in the neighborhood of the dipole have an intriguing structure due to interference between the dipole radiation and the reflected light by the mirrors. Numerous singularities and vortices appear in the sub-wavelength region between the dipole and the surfaces. We present a method to find the locations of the vortices and singularities without regard to the details of the flow pattern. The radiation field induces a surface current density in the mirrors. The direction of the current is predominantly in the radial direction for a linear dipole, but it alternates between outgoing and incoming across singular curves. We show that the field line pattern expands with a phase velocity larger than the speed of light. For a circular dipole, there appears a spiral which runs inward. The current initially flows in along this spiral. Then the current leaves again along an outgoing spiral, which spirals inside the incoming spiral. Current can flow from one mirror to the other, and we show that the current always crosses the intersection line at a 90° angle.
Symmetries and turbulence modeling
Authors: Klingenberg D. , Oberlack M. , Pluemacher D.
Published: February 2020

This work applies new insights into turbulent statistics gained by Lie symmetry analysis to the closure problem of turbulence. Founded in the mathematics of partial differential equations, Lie symmetries have helped advances in many fields of modern physics. The main reason for this is their ability to encode important physical principles that are implicitly expressed by governing equations. Newly discovered symmetries of the multi-point correlation equations describing turbulent motion have been shown to encode two central effects of turbulent statistics: intermittency and non-Gaussianity. Moreover, these symmetries play a pivotal role in obtaining turbulent scaling laws such as the logarithmic law of the wall. Evidently, correctly preserving these symmetry properties in a turbulence model would render it capable of accurately predicting important effects of turbulent statistics and turbulent scaling. As these symmetry constraints have so far not been taken into account when devising turbulence models, we present a completely new modeling framework that can yield models fulfilling these conditions. In order to accomplish this, it turns out to be helpful, if not necessary, to introduce an entirely new symmetry-based modeling strategy that allows systematically constructing equations based on symmetry constraints imposed on them. From these considerations, it can be shown that in order to create meaningful turbulence models that fulfill these constraints, it is necessary to introduce a new velocity and pressure field. A possible skeleton of model equations for second moment closure is presented.
Promoting reactivity of photoexcited hot electrons in small-sized plasmonic metal nanoparticles that are supported on dielectric nanospheres
Authors: Rasamani Kowsalya Devi , Sun Yugang
Published: February 2020

Plasmonic metal nanoparticles (NPs) represent a promising class of photocatalysts to drive chemical transformations by the photoexcited hot electrons in the NPs. In this work, the dependence of photon-to-chemical conversion efficiency on the size of plasmonic silver nanoparticles (Ag NPs) has been comprehensively studied with the use of the photocatalytic degradation of methylene blue as a probe reaction. Comparison of Ag NPs with two different sizes (6 nm and 13 nm in diameter) highlights that the smaller sized Ag NPs favor the photocatalytic activity by positively translating the high efficiency of hot electron generation to the hot-electron-driven chemical reaction on the surface of the Ag NPs. Loading the small Ag NPs to the dielectric silica nanospheres (SiOX NSs, average diameter of 400 nm) with high surface coverage increases the light absorption power in the Ag NPs due to the surface light scattering resonances of the SiOX NSs and interparticle plasmon coupling of the adjacent Ag NPs. The enhanced light absorption can also be rendered to the improved photocatalytic activity. This design principle of plasmonic photocatalysts provides a promise of utilizing solar energy to drive desirable chemical reactions with high photon-to-chemical conversion efficiency.
Ambient pressure x-ray photoelectron spectroscopy study of water formation and adsorption under two-dimensional silica and aluminosilicate layers on Pd(111)
Authors: Jhang Jin-Hao , Boscoboinik J. Anibal , Altman Eric I.
Published: February 2020

Ambient pressure x-ray photoelectron spectroscopy (AP-XPS) supported by density functional theory (DFT) calculations was used to characterize the interaction of water with two-dimensional (2D) silica and aluminosilicate bilayers on Pd(111). Starting with oxygen adsorbed at the SiO2/Pd interface, exposure to water caused the SiO2-derived XPS peaks to shift to higher binding energy and the removal of an O 1s feature associated with interfacial adsorbed oxygen. These observations were attributed to the formation of a mixed water–hydroxyl interface, which eliminates the interfacial dipolar layer, and its associated electrostatic potential, created by adsorbed oxygen. Interfacial oxygen also reacted with H2 to produce adsorbed water which also caused an upward binding energy shift of the SiO2 peaks. Spectra recorded under 0.5 Torr water revealed additional water adsorption and a further shift of the overlayer peaks to higher binding energy. Incorporating Al into the 2D material caused the bilayer peaks to shift to lower binding energy which could be explained by electron donation from the metal to the bilayer. Although the stronger interaction between the bilayer and Pd substrate should restrict interfacial adsorption and reaction, similar trends were observed for water and hydrogen exposure to interfacial adsorbed oxygen. Less water adsorption was observed at the aluminosilicate interface which is a consequence of Al strengthening the bond to the metal substrate. The results reveal how the sensitivity of XPS to interfacial dipoles can be exploited to distinguish reactions taking place in confined spaces under 2D layers and how tuning the composition of the 2D layer can impact such reactions.
Switching On/Off the Intramolecular Hydrogen Bonding of 2-Methoxyphenol Conformers: An NMR Study
Authors: Backler Frederick , Wang Feng
Published: February 2020

Intramolecular hydrogen bonding of 2-methoxyphenol (2-MP, guaiacol) is studied using NMR spectroscopy combined with quantum mechanical density functional theory (DFT) calculations. The hydrogen bonding of OH⋯O and HO⋯H is switched on in the conformers of anti–syn (AS, 99.64% dominance) and anti–gauche (AG), respectively, with respect to the anti–anti (AA) conformer (without either such hydrogen bonding interactions). It confirms that the 13C and 1H NMR chemical shift of AS dominates the measured NMR spectra, as the AS conformer reproduces the measurements in CDCl3 solvent (RMSD of 1.86ppm for 13C NMR and of 0.27ppm for 1H NMR). The chemical shift of hydroxyl H(1) at 5.66 pm is identified as the fingerprint of the OH(1)⋯OCH3 hydrogen bonding in AS, as it exhibits a significant deshielding from H(1) of AA (4.24ppm) and H(1) of AG (4.38ppm) without such OH(1)⋯OCH3 hydrogen bonding. The AG conformer (C1 point group symmetry) possesses a less strong hydrogen bonding of HO⋯HCH2O, with the methoxyl group out of the aromatic phenol plane. The substituent effect of AG due to the resonance interaction of methoxyl being out of plane in a concentrated solution shifts the ortho- and para-aromatic carbons, C(3)/C(5), of the AG to ~125.05/125.44ppm from the corresponding carbons in AS at 108.81/121.60ppm. The hydrogen bonding exhibits inwards reduction of IR frequency regions of AS and AG from AA. Finally, energy decomposition analysis (EDA) indicates that there is a steric energy of 45.01kcal mol−1 between the AS and AG when different intramolecular hydrogen bonding is switched on.
Multiscale relationships between stream temperature and juvenile recruitment in an imperilled freshwater fish
Authors: Turschwell Mischa P. , Stewart-Koster Ben , Balcombe Stephen R. , Sheldon Fran , Peterson Erin E.
Published: February 2020

The distribution and population structure of organisms is governed by a broad suite of biotic and abiotic variables, interacting across multiple scales. Recruitment is a key demographic process critical to the maintenance of successful populations. Isolating and quantifying the multiscale environmental drivers of recruitment is vital for species conservation, especially for those species with traits that increase their susceptibility to local extirpation. We developed a Bayesian hierarchical model to quantify the relationship between the rate of recruitment in a locally threatened river blackfish (Gadopsis marmoratus) and environmental predictors across two spatial scales. There was a 0.99 probability that increased broad-scale stream temperature negatively affected juvenile recruitment rate. We also found that there was a 0.97 probability that the fine-scale relationship between recruitment rate and riparian foliage cover was dependent on temperature. This suggests that broad-scale thermal conditions provide the template upon which at least one local environmental variable influences recruitment rate. Understanding drivers influencing key population processes and the spatial scales at which they operate is critical to gaining an insight into likely changes in population persistence for potentially imperilled species, along with the potential future effects of habitat degradation and climate warming on freshwater fishes in general.
Asian inland wildfires driven by glacial–interglacial climate change
Authors: Han Yongming , An Zhisheng , Marlon Jennifer R. , Bradley Raymond S. , Zhan Changlin , Arimoto Richard , Sun Youbin , Zhou Weijian , Wu Feng , Wang Qiyuan , Burr George S. , Cao Junji
Published: February 2020

Significance

We reconstructed a unique record of soot variations from a classic Chinese loess section that reflects regional-to-continental scale high-intensity fires in central Asia over the entire Quaternary. This study shows cyclicity of wildfire over glacial–interglacial intervals. High-intensity wildfires were more common and dust loads were high during dry and cold glacial periods, implying a synchronous response to climate change. Our study suggests potential linkages among wildfire, mineral dust, marine biogeochemical cycles, atmospheric CO
2
, and glacial–interglacial climate change. Understanding these connections among earth systems provides insights into climate dynamics during the geological past and may improve predictions for the future.
Safeguarding intestine cells against enteropathogenic
Escherichia coli
by intracellular protein reaction, a preventive antibacterial mechanism
Authors: Qiu Jiaming , Nie Yunyu , Zhao Yuan , Zhang Yu , Li Linting , Wang Rui , Wang Miaomiao , Chen Sheng , Wang Jianhao , Li Yong-Qiang , Xia Jiang
Published: February 2020

Significance

New antibacterial strategies that circumvent existing mechanisms hold promise in the fight against drug-resistant bacteria. Here we present an antibacterial mechanism that safeguards cells and animals by shutting down an intracellular signal through a site-selective covalent peptide-protein reaction instead of acting on bacterium cells. The novelty of this work is multifold, including a cysteine- specific reaction at an SH3 domain of an adaptor protein in cells, selective blockage of the second SH3 domain of Nck but not the other two SH3 domains, and prevention of EPEC-induced infection in animals for at least 12 h by reactive peptide. Thus, this preventative mechanism differs significantly from the bactericidal actions of antibiotics.
Nanoscale precipitates as sustainable dislocation sources for enhanced ductility and high strength
Authors: Peng Shenyou , Wei Yujie , Gao Huajian
Published: February 2020

Significance

Precipitates in a material are traditionally thought of as dislocation obstacles that lead to elevated strength and reduced ductility. In contrast, recent experiments suggest that nanoscale precipitates facilitate both high strength and large ductility. To help resolve this apparent paradox, here we reveal that nanoprecipitates provide a unique type of dislocation sources that are activated at sufficiently high stress levels and render uniform plasticity by simultaneously serving as efficient dislocation sources and obstacles to dislocation motion, giving rise to sustained deformability. The findings can guide development of next generation of materials such as multiple-element alloys with precipitate engineering.
Neonicotinoid and sulfoximine pesticides differentially impair insect escape behavior and motion detection
Authors: Parkinson Rachel H. , Zhang Sinan , Gray John R.
Published: February 2020

Insect nervous systems offer unique advantages for studying interactions between sensory systems and behavior, given their complexity with high tractability. By examining the neural coding of salient environmental stimuli and resulting behavioral output in the context of environmental stressors, we gain an understanding of the effects of these stressors on brain and behavior and provide insight into normal function. The implication of neonicotinoid (neonic) pesticides in contributing to declines of nontarget species, such as bees, has motivated the development of new compounds that can potentially mitigate putative resistance in target species and declines of nontarget species. We used a neuroethologic approach, including behavioral assays and multineuronal recording techniques, to investigate effects of imidacloprid (IMD) and the novel insecticide sulfoxaflor (SFX) on visual motion-detection circuits and related escape behavior in the tractable locust system. Despite similar LD
50
values, IMD and SFX evoked different behavioral and physiological effects. IMD significantly attenuated collision avoidance behaviors and impaired responses of neural populations, including decreases in spontaneous firing and neural habituation. In contrast, SFX displayed no effect at a comparable sublethal dose. These results show that neonics affect population responses and habituation of a visual motion detection system. We propose that differences in the sublethal effects of SFX reflect a different mode of action than that of IMD. More broadly, we suggest that neuroethologic assays for comparative neurotoxicology are valuable tools for fully addressing current issues regarding the proximal effects of environmental toxicity in nontarget species.
Assessing the reliability of a clothing-based forensic identification
Authors: Nightingale Sophie J. , Farid Hany
Published: February 2020

A 2009 report by the National Academy of Sciences was highly critical of many forensic practices. This report concluded that significant changes and advances were required to ensure the reliability across the forensic sciences. We examine the reliability of one such forensic technique used for identification based on purported distinct patterns on the seams of denim pants. Although first proposed more than 20 years ago, no thorough analysis of reliability or reproducibility of this forensic technique has previously been reported. We performed a detailed analysis of this forensic technique to determine its reliability and efficacy.