bluuebunny/crossref_metadata_2025 huggingface dataset:
Efficacy of Individualized Homeopathic Medicines in Plantar Fasciitis: Double-blind, Randomized, Placebo-Controlled Clinical Trial
Authors: Shahid Sana , Ghosh Shubhamoy , Chakraborty Ardhendu Shekhar , Maiti Shukdeb , Sadhukhan Satarupa , Koley Munmun , Saha Subhranil
Published: September 2021

Introduction Plantar fasciitis (PF) is a chronic degenerative condition causing marked thickening and fibrosis of the plantar fascia, and collagen necrosis, chondroid metaplasia and calcification. There is little convincing evidence in support of various approaches, including homeopathy, for treating PF. This study was undertaken to examine the efficacy of individualized homeopathic medicines (IHMs) compared with placebo in the treatment of PF.

Methods A double-blind, randomized, placebo-controlled trial was conducted at the outpatient departments of Mahesh Bhattacharyya Homoeopathic Medical College and Hospital, West Bengal, India. Patients were randomized to receive either IHMs or identical-looking placebo in the mutual context of conservative non-medicinal management. The Foot Function Index (FFI) questionnaire, as an outcome measure, was administered at baseline, and every month, up to 3 months. Group differences (unpaired t-tests) and effect sizes (Cohen's d) were calculated on an intention-to-treat sample. The sample was analyzed statistically after adjusting for baseline differences.

Results The target sample size was 128; however, only 75 could be enrolled (IHMs: 37; Placebo: 38). Attrition rate was 9.3% (IHMs: 4, Placebo: 3). Differences between groups in total FFI% score favored IHMs against placebo at all the time points, with large effect sizes: month 1 (mean difference, −10.0; 95% confidence interval [CI], −15.7 to −4.2; p = 0.001; d = 0.8); month 2 (mean difference, −14.3; 95% CI, −20.4 to −8.2; p <0.001; d = 1.1); and month 3 (mean difference, −23.3; 95% CI, −30.5 to −16.2; p <0.001; d = 1.5). Similar significant results were also observed on three FFI sub-scales (pain%, disability%, and activity limitation%). Natrum muriaticum (n = 14; 18.7%) and Rhus toxicodendron and Ruta graveolens (n = 11 each; 14.7%) were the most frequently prescribed medicines. No harms, serious adverse events, or intercurrent illnesses were recorded in either of the groups.

Conclusion IHMs acted significantly better than placebo in the treatment of PF; however, the trial being underpowered, the results should be interpreted as preliminary only. Independent replications are warranted.

Trial registration CTRI/2018/10/016014.
International Microsurgery Club Webinar Series—Bridging the Knowledge Gap during the COVID-19 Pandemic
Authors: Sung Cheyenne Wei-Hsuan , Huang Jung-Ju , Mao Shih-Hsuan , Heredero Susana , Chen Wei F. , Nguyen John , Pereira Nicolas , Chen Lisa Wen-Yu , Lin Jennifer An-Jou , Lu Johnny Chuieng-Yi , Koshima Isao , Chang Tommy Nai-Jen
Published: September 2021

Background The impact of the coronavirus disease 2019 (COVID-19) outbreak shut down most conferences. To minimalize the influence, virtual meetings sprang up subsequently. International Microsurgery Club (IMC), as one of the largest professionals-only online microsurgery education groups worldwide, began to host regular weekend webinars during the pandemic to fill the knowledge gap. This study aims to discuss how webinars have fundamentally changed the way knowledge is delivered and exchanged.

Methods From February 29, 2020 to March 14, 2021, 103 IMC webinars were reviewed and analyzed in detail to determine the use, benefit, and effect. A comparison between webinars hosted by the different societies was made as well. A questionnaire survey focusing on attendees' behavior, attitude, and using habit about webinars was also made.

Results As for the 103 IMC webinar events, the peak participants were 112.3 people in average. The members requesting to join IMC abruptly increased during the pandemic, and the group activity increased dramatically. From the questionnaire (n = 68), the satisfaction level was high (8.88 ± 1.18/10). The respondents were most satisfied with the good quality of the speakers (73.5%). Not only hosts our webinar series but IMC also serves as the platform that welcomes webinars from other societies to share their information. In September 2020, International Microsurgery Webinar League was established via the significant webinar hosts, with more than 300 recorded webinar talks connected successfully.

Conclusion As the knowledge revolution driven by COVID-19 will continue, IMC will keep playing an essential role in exploring new and emerging opportunities to improve knowledge dissemination worldwide beyond the space-time boundary.
Early Antibiotic Exposure in Low-Risk Late Preterm and Term Infants
Authors: Sonney Kelley M. , Guindon Michael G. , Aden James K. , Drumm Caitlin M.
Published: September 2021

Objective This study aimed to examine the epidemiology of antibiotic exposure and early onset sepsis (EOS) in late preterm and term infants born via cesarean section with rupture of membranes less than 10 minutes.

Study design Retrospective review of 1,187 late preterm and term infants born at Brooke Army Medical Center between January 1, 2012 and August 29, 2019. Subjects were assessed for factors related to antibiotic treatment. Statistical analysis was performed to compare infants treated with antibiotics versus observation.

Result An early blood culture was obtained from 234 (19.7%) infants; 170 (14.3%) were treated with antibiotics. Infants treated with antibiotics were significantly younger (p < 0.0001), smaller (p < 0.0001), more often diagnosed with respiratory distress (p < 0.0001), and were more frequently admitted to the neonatal intensive care unit (p < 0.0001). There were no cases of culture proven EOS.

Conclusion Although this population lacks risk factors for the development of EOS, a significant percentage was treated with antibiotics. This population may benefit from future antibiotic stewardship efforts.

Key Points
Large Parenchymal Perianeurysmal Cyst: A Case Report
Authors: Birua Gyani J.S. , Tyagi Gaurav , Beniwal Manish , Srinivas Dwarakanath , Rao Shilpa
Published: September 2021

Parenchymal perianeurysmal cysts are rare. We report a case of 50-year-old woman who presented with persistent headaches and episodes of vomiting for the last 2 months. Magnetic resonance imaging of the brain showed a well-defined solitary cystic lesion with a mural nodule measuring 5.4 × 5.2 × 4.6 cm in the right basifrontal region. The mural nodule was cortically based. It was hypointense on T2-weighted fluid-attenuated inversion recovery and showed intense contrast enhancement with few nonenhancing areas—no evidence of diffusion restriction. The cyst wall was nonenhancing, and magnetic resonance angiogram was unremarkable. Differential diagnoses included intra-axial gliomas such as ganglioglioma and pleomorphic xanthoastrocytoma. Right pterional craniotomy and a transcortical approach were made. Subtotal excision of cyst and clipping of right middle cerebral artery bifurcation thrombosed aneurysm were done. After 6 months of follow-up, patient is stable without any deficits. A parenchymal perianeurysmal cyst is a rare entity; it is crucial to be considered a differential diagnosis in any cystic lesion with the mural nodule.
Imaging and Pathological Features of Alveolar Soft Part Sarcoma: Analysis of 16 Patients
Authors: Gulati Malvika , Mittal Abhenil , Barwad Adarsh , Pandey Rambha , Rastogi Sameer , Dhamija Ekta
Published: September 2021

Context Alveolar soft part sarcoma (ASPS) is a rare soft tissue tumor most commonly occurring in deep intramuscular plane of lower extremities of adolescents and young adults. It is a highly vascular, slow growing tumor with malignant potential having lung as the most common site of metastases at the time of presentation.

Aims The aim is to review the imaging findings of ASPS and determine characteristic imaging features of this rare tumor.

Materials and Methods Sixteen patients having histopathological diagnosis and preoperative imaging of ASPS attending the dedicated sarcoma clinic at our institute were included in the study. The demographic, clinical, and imaging data were retrieved from the case records and then evaluated for characteristic imaging features which may raise suspicion of ASPS.

Results The patients ranged from 3 to 72 years of age and with a slight male preponderance. Of the eight CECTs evaluated, 62.5% tumors showed well-defined lobulated margins, 87.5% cases showed intense enhancement with presence of feeder vessels. On CEMRI of 10 patients, 70% had well circumscribed lobulated margins with intense enhancement and tortuous flow voids in most of them. All cases showed T2 hyperintense signal. Fourteen of 16 (87.5%) patients had metastatic disease with lung as the most common site (92.8%).

Conclusion ASPS is a rare soft tissue sarcoma seen in children and young adults. Imaging may mimic a vascular malformation due to the presence of tortuous feeders. Misdiagnosis at an early stage may lead to later metastatic presentation of the disease, thus emphasizing the need to suspect it on imaging.
A Triad of Unilateral Renal Dysgenesis with Ipsilateral Seminal Vesical and Ejaculatory Duct Obstruction: An Uncommon Urogenital Congenital Anomaly, Zinner Syndrome—A Case Report
Authors: Gorantla Rajani , Allu Sameera , Rao Ankamma
Published: September 2021

Zinner syndrome is a rare congenital anomaly of the urogenital system resulting from an in utero insult during the first trimester. This entity comprises a triad of unilateral renal agenesis/dysgenesis with ipsilateral seminal vesical and ejaculatory duct obstruction. This combination of urinary and genital abnormalities occurs because of the closely related embryological origin of these structures from the distal mesonephric (Wolffian) duct. Nearly 200 cases of seminal vesical cysts with ipsilateral renal agenesis have been reported in the literature. The affected person generally presents in early adulthood when the reproductive activity commences. In this report, we present a case of a 22-year-old male with complaints of painful ejaculation.
Fast, accurate, point-of-care COVID-19 pandemic diagnosis enabled through advanced lab-on-chip optical biosensors: Opportunities and challenges
Authors: Asghari Aref , Wang Chao , Yoo Kyoung Min , Rostamian Ali , Xu Xiaochuan , Shin Jong-Dug , Dalir Hamed , Chen Ray T.
Published: September 2021

The sudden rise of the worldwide severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic in early 2020 has called into drastic action measures to perform instant detection and reduce the rate of spread. Common clinical and nonclinical diagnostic testing methods have been partially effective in satisfying the increasing demand for fast detection point-of-care (POC) methods to slow down further spread. However, accurate point-of-risk diagnosis of this emerging viral infection is paramount as the need for simultaneous standard operating procedures and symptom management of SARS-CoV-2 will be the norm for years to come. A sensitive, cost-effective biosensor with mass production capability is crucial until a universal vaccination becomes available. Optical biosensors can provide a noninvasive, extremely sensitive rapid detection platform with sensitivity down to ∼67 fg/ml (1 fM) concentration in a few minutes. These biosensors can be manufactured on a mass scale (millions) to detect the COVID-19 viral load in nasal, saliva, urine, and serological samples, even if the infected person is asymptotic. Methods investigated here are the most advanced available platforms for biosensing optical devices that have resulted from the integration of state-of-the-art designs and materials. These approaches include, but are not limited to, integrated optical devices, plasmonic resonance, and emerging nanomaterial biosensors. The lab-on-chip platforms examined here are suitable not only for SARS-CoV-2 spike protein detection but also for other contagious virions such as influenza and Middle East respiratory syndrome (MERS).
On global existence of L2 solutions for 1D periodic NLS with quadratic nonlinearity
Authors: Fujiwara Kazumasa , Georgiev Vladimir
Published: September 2021

We study the 1D nonlinear Schrödinger equation with non-gauge invariant quadratic nonlinearity on the torus. The Cauchy problem admits trivial global dispersive solutions, which are constant with respect to space. The non-existence of global solutions has also been studied only by focusing on the behavior of the Fourier 0 mode of solutions. However, the earlier works are not sufficient to obtain the precise criteria for the global existence for the Cauchy problem. In this paper, the exact criteria for the global existence of L2 solutions are shown by studying the interaction between the Fourier 0 mode and oscillation of solutions. Namely, L2 solutions are shown a priori not to exist globally if they are different from the trivial ones.
The reversibility of magnetic reconnection
Authors: Xuan M. , Swisdak M. , Drake J. F.
Published: September 2021

The reversibility of the transfer of energy from the magnetic field to the surrounding plasma during magnetic reconnection is examined. Trajectories of test particles in an analytic field model demonstrate that irreversibility is associated with separatrix crossings and passages through regions of weaker magnetic field. Inclusion of a guide field enhances the magnetization of particles and the extent to which forward and reverse trajectories overlap. Full kinetic simulations with a particle-in-cell code support these results and demonstrate that while time-reversed simulations at first “un-reconnect,” they eventually evolve into a reconnecting state.
A simple and efficient passive vibration isolation system for large loads in closed-cycle cryostats
Authors: Wiens Eugen , Schiller Stephan
Published: September 2021

We present a system for passive damping of vibrations along three spatial degrees of freedom for cryostats equipped with closed-cycle coolers. The system, designed to isolate a payload of 30 kg, consists of two stages of isolation for vibrations in the vertical direction. The first isolation stage incorporates a trapezoidal beryllium copper cantilever blade. The second stage is attached to the blade via a steel wire and consists of four extension springs with an extended length of 370 mm. At 1.6 K, the stages possess vertical resonance frequencies of 2.1 and 1.3 Hz, respectively. The vertical length of the setup with a cumulative length of 580 mm also acts as a pendulum with a resonance frequency of 0.65 Hz. In the frequency band from 5 to 200 Hz, the frequency-integrated acceleration decreased from 6.7 × 10−3 to 4.3 × 10−5 g along the horizontal direction and from 4.3 × 10−3 to 7.2 × 10−5 g along the vertical direction. This corresponds to a reduction in vibrations by factors of 156 and 60, respectively. Overall, we achieve a simple, robust, and cost-efficient vibration isolation system for upgrading standard-type cryostats.
Thermal conductivity minimum of graded superlattices due to phonon localization
Authors: Guo Yangyu , Bescond Marc , Zhang Zhongwei , Xiong Shiyun , Hirakawa Kazuhiko , Nomura Masahiro , Volz Sebastian
Published: September 2021

Anderson localization of thermal phonons has been shown only in few nanostructures with strong random disorder by the exponential decay of transmission to zero and a thermal conductivity maximum when increasing the system length. In this work, we present a path to demonstrate the phonon localization with distinctive features in graded superlattices with short-range order and long-range disorder. A thermal conductivity minimum with system length appears due to the exponential decay of transmission to a non-zero constant, which is a feature of partial phonon localization caused by the moderate disorder. We provide clear evidence of localization through the combined analysis of the participation ratio, transmission, and real-space phonon number density distribution based on our quantum transport simulation. The present work would promote heat conduction engineering by localization via the wave nature of phonons.
Laser-Based Primary Thermometry: A Review
Authors: Gotti R. , Lamperti M. , Gatti D. , Marangoni M.
Published: September 2021

Laser-based primary thermometry was initiated almost 15 years ago by the proposal to determine the absolute temperature of a gas at thermodynamic equilibrium through the Doppler width of an associated absorption transition, exploiting the potentially very accurate measurement of an optical frequency to infer the elusive thermal energy of a molecular or atomic absorber. This approach, commonly referred to as Doppler broadening thermometry, has benefited across the years from substantial improvements, of both technical and fundamental nature, eventually reaching an accuracy of about 10 ppm on the temperature determination in the best cases. This is sufficient for Doppler broadening thermometry to play a significant role in the practical realization of the new kelvin, which follows the 2019’s redefinition from a fixed value of the Boltzmann constant, and to tackle the challenge, among others, to quantify and possibly fix systematic uncertainties of the international temperature scale of 1990. This paper reviews and comparatively analyzes methods and results achieved so far in the field of laser-based primary thermometry, also including spectroscopic approaches that leverage the temperature-dependent distribution of line intensities and related absorbances across the rovibrational band of a molecular sample. Although at an early stage of development, these approaches show a promising degree of robustness with respect to the choice of the line-shape model adopted for the fitting of the absorption spectra, which is a delicate aspect for all laser-based thermometers. We conclude by identifying possible technical and scientific evolution axes of the current scenario.
Comparison of amplitude method of roughness-induced swept-wing transition prediction with experiment
Authors: Ustinov M. V. , Kachanov Y. S.
Published: September 2021

An amplitude method of laminar-turbulent transition prediction in the boundary layer on a swept wing has been developed and tested. The method computes the amplitudes and spectra of steady cross-flow instability modes generated by surface roughness. The transition criterion is based on the crucial, threshold values of maximal or local amplitudes of these perturbations found from experiments. Statistical methods describing the intermittency in the transition zone based on this criterion are proposed.
Modeling the effect of flow-induced mechanical erosion during coffee filtration
Authors: Mo Chaojie , Johnston Richard , Navarini Luciano , Ellero Marco
Published: September 2021

The espresso extraction process involves a complex transport inside a geometry-changing porous medium. Large solid grains forming the majority of the porous medium can migrate, swell, and consolidate, and they can also morphologically change during flow, i.e., being mechanically eroded by hydrodynamic forces. These processes can, in turn, have a significant back-effect on the flow and the related coffee extraction profiles. In this article, we devise a bottom–up erosion model in the framework of smoothed dissipative particle dynamics to consider flow-induced morphological changes of the coffee grains. We assume that the coffee grains are not completely wetted and remain brittle. We found that heterogeneity in both the filtration direction and the transverse direction can be induced. The former is controlled by the angle of internal friction while the latter is controlled by both the cohesion parameter and the angle of internal friction. Not restricted to the modeling of espresso extraction, our model can also be applied to other eroding porous media. Our results suggest that, under ideal porous flow conditions, we can control the heterogeneity (in both the pressure drop direction and the transverse direction) of an eroding medium by tuning the yield characteristics of the eroding material.
Black tea interfacial rheology and calcium carbonate
Authors: Giacomin Caroline E. , Fischer Peter
Published: September 2021

An interfacial phenomenon can be observed in the kitchen in a cup of black tea. When tea is left to cool after steeping, a thin film at the air–water interface can form. In certain conditions, this film is observable by naked eye and, when disturbed, cracks visibly like sea ice. The mechanical properties of this interfacial film are assessed using bicone interfacial rheometry. Water hardness, acidity, the presence of sugar or milk, tea concentration, and brewing temperature all affect the formation of this film. Interfaces formed in hard water (200 mg CaCO3/L) exhibit increased elastic modulus vs those in moderately hard water (100 mg CaCO3/L), soft water (50 mg CaCO3/L), and Milli-Q water. All films formed in chemically hardened water exhibit yielding point behavior in the interfacial oscillatory shear. Film physical thickness shows no correlation with measured physical strength. Conditions forming the strongest film, chemically hardened water, may be industrially useful in packaged tea beverages for preferable shelf stability and for emulsion stabilization of milk tea products. Conditions forming weakened films, addition of citric acid, may be useful for dried tea mixes. In lab conditions, the film visibility is obscured due to purity of tea ingredients and careful washing. However, the film physically forms and can still be measured through interfacial rheometry.
Geometry optimization speedup through a geodesic approach to internal coordinates
Authors: Hermes Eric D. , Sargsyan Khachik , Najm Habib N. , Zádor Judit
Published: September 2021

We present a new geodesic-based method for geometry optimization in a basis set of redundant internal coordinates. Our method updates the molecular geometry by following the geodesic generated by a displacement vector on the internal coordinate manifold, which dramatically reduces the number of steps required to converge to a minimum. Our method can be implemented in any existing optimization code, requiring only implementation of derivatives of the Wilson B-matrix and the ability to numerically solve an ordinary differential equation.
Emission spectroscopy with coded apertures for enhanced dimensionality
Authors: Richardson Daniel R.
Published: September 2021

A coded aperture is used to demonstrate emission spectroscopy from multiple one-dimensional measurement locations simultaneously with a single camera. The coded aperture mask has several columns of periodic apertures, each with a unique spatial frequency. Light transmitted through all mask columns is detected through an imaging spectrometer. Dispersed light from the various mask columns overlaps on the spectrometer camera but is separated using Fourier-domain filtering using the known spatial frequencies of the mask. As the coded aperture is placed at an image plane, each Fourier-filtered spectrogram comes from a unique one-dimensional measurement location. This technique represents a significant increase in the amount of spatially and spectrally resolved emission data available using a single emission spectrometer and camera at the expense of some spatial resolution due to the Fourier filtering. This instrument is particularly useful for studying transient, non-repeating events. Megahertz-rate emission spectroscopy from five one-dimensional measurement locations is demonstrated with explosive fireballs using a single camera. Optical design parameters and instrument performance characteristics are discussed.
Experimental and numerical investigation of CO2 laser ablation of fused silica with sub-microsecond pulses
Authors: Cifuentes Quintal C. , Cormont P. , Gallais L.
Published: September 2021

The CO2 laser material interaction is commonly used for thermal treatments and processing of fused silica glasses. As the laser pulse duration decreases down to a few tens of microseconds, the heat-affected depth in the material decreases up to the point where it has the same magnitude as the laser radiation penetration depth, which is an interesting operating point for applications that require minimal heat-affected zone. In this work, we explore the effects of CO2 laser pulses in the range of 100 μs to a few milliseconds on the laser ablation of polished fused silica surfaces, based on experiments and numerical simulations. We particularly study the evolution of surface profile as a function of the number of applied pulses. The results suggest that the ablation depth can be accurately controlled from a few hundreds of nanometers to a few tens of micrometers by adjusting the combination of the number of applied pulses and pulse duration.
Elastic, piezoelectric, and dielectric properties of rare-earth calcium oxoborates RCa4O(BO3)3 (R = Er, Y, Dy, Gd, Sm, Nd, La)
Authors: Münchhalfen Marie , Schreuer Jürgen , Reuther Christoph , Mehner Erik , Stöcker Hartmut
Published: September 2021

Large single crystals of rare-earth calcium oxoborates RCa4O(BO3)3 with R=Er, Y, Dy, Gd, Sm, Nd, La (RCOB) were grown by the Czochralski method. Complete sets of dielectric, piezoelectric stress, and elastic stiffness coefficients of the RCOB crystal species were determined at ambient conditions using a combination of resonant ultrasound spectroscopy and the substitution method. The results are inherently consistent and reveal clear crystal chemical trends, with the size of the trivalent cation playing an important role. In particular, the longitudinal and shear aggregate elastic stiffnesses, c11iso and c44iso, decrease from about 165 to 154 GPa and, respectively, 45 to 41 GPa from the smallest to the largest R3+ cation of the investigated crystal species, while the dielectric coefficients ϵ22 and ϵ33 increase. However, the maximum longitudinal piezoelectric effect peaks with 8.6pCN−1 at NdCOB, the species where the radius of R3+ best matches the one of Ca2+. Increasing differences in the size of R3+ and Ca2+ lead to anisotropic stresses in the crystal lattice, which are partially relaxed by an increasing degree of cation disorder.
Hydrodynamic regimes and drag on horizontally pulled floating spheres
Authors: Kamoliddinov Farrukh , Vakarelski Ivan U. , Thoroddsen Sigurdur T.
Published: September 2021

We use high-speed imaging to investigate the movement of a floating sphere pulled horizontally along a water surface. The model sphere is 10 cm in diameter and has half of the water density resulting in a half-submerged static sphere. By varying the pulling force, we investigate the flow dynamics in the subcritical Reynolds number range, of Re ≈ 2 × 104 to 2 × 105. We characterize three hydrodynamic regimes with the increase in the pulling force, to which we refer to as: low Froude number, Fr < 0.6, intermediate, 0.6 < Fr < 1.2 and high Froude number, Fr > 1.2 regimes. In the low Fr regime, the sphere moves with little disturbance of the water surface and the drag is close to half of the drag on a fully submerged sphere. In the intermediate Fr regime, a pronounced wave pattern is developed which together with the dipping of the sphere below the water level leads to an increase in the drag force. Based on a potential flow approximation for the downward force on the sphere moving along the surface, we derive a semiempirical relation for the sphere dipping as a function of the Froude number. Finally, in the high Fr regime, the sphere movement switches to a mode of periodic dipping below and surfacing above the water surface. The periodic vertical motion portrays a decrease in the average drag force.
Molecular passivation of MAPbI3 perovskite films follows the Langmuir adsorption rule
Authors: Zeng Peng , Zhang Qinghong , Zhang Yifeng , Cai Bing , Feng Guanqun , Wang Yixiao , Zeng Chengsong , Zhang Wen-Hua , Liu Mingzhen
Published: September 2021

Surface defect passivation through additional molecular bonding plays a crucial role in optimization of perovskite-based photovoltaic devices. So far, quantization of the defect site coverage by molecular passivation remains unclear from a macroscopic view. We herein unravel the coverage possibility of the surface defect sites of perovskite films by the added molecule passivators upon an MAPbI3 perovskite system. Concerns of inconsistent time-resolved photoluminescence (TRPL) spectroscopic measurements are dispelled by vapor-deposition fabrications of highly uniform perovskite films. The surface defect densities of perovskite films are derived from global fittings of the charge carrier dynamics to the measured TRPL decays. It is revealed the Langmuir adsorption relationship of the defect site coverage with respect to the added amount of tri-n-octylphosphine oxide passivation molecules. Our work supplements the dynamical bonding model of the molecular passivation process and provides reliable knowledge upon the bonding process between molecules and defects, which leads to rationalized surface passivation methodologies in perovskite photovoltaics communities.
Prolonging lifetime of photogenerated carriers in WO3 nanowires by oxygen vacancies engineering for enhanced photoelectrocatalytic oxygen evolution reaction
Authors: Liu Zeyu , Jiang Zhenzhen , Luo Xingfang , Zhou Wenda , Chen Mingyue , Su Meixia , Shi Ping , Hou Yinhui , Xiong Ziren , Li Qinliang , Yu Ting , Yuan Cailei
Published: September 2021

WO3 nanowires (NWs) have emerged as a promising alternative electrocatalyst for the photoelectrochemical (PEC) oxygen evolution reaction (OER), due to their nontoxicity, low cost, good stability, and strong photocatalytic oxidation ability. However, a significant challenge is limited by the poor electrical conductivity and the rapid recombination rate of photogenerated carriers. This paper reports a facile and effective way to synthesize the WO3 NWs with oxygen vacancies (Ov-WO3 NWs), which have high PEC OER activity and good stability. Photoelectric measurements indicate that the Ov-WO3 NW-based device shows a good light-harvesting property under visible light and a prolonged photoresponse time. Electrochemical impedance spectra measurements reveal a reduced value of Rct denoting an improved electrical conductivity, which should be responsible for the superior PEC OER performance. Our work provides a strategy for fabricating efficient water-splitting electrodes to help establish rational design principles for future OER catalysts.
Mechanical tunability of flexoelectricity in elastomers
Authors: Ji Hui , Shao Shubao , Liu Kaiyuan , Shang Hongxing , Zhu Yuanwei , Wu Tonghui , Shen Shengping , Zhang Shuwen , Xu Minglong
Published: September 2021

As a strain-gradient-induced electric polarization, flexoelectricity in dielectric materials is benefiting from its size effect and manipulating strain gradients. Dielectric elastomers (DE) are stretchable with tunable physical and chemical properties. Large deformation enables big strain gradient, highlighting flexoelectricity during electro-mechanical coupling procedures. High and tunable electro-mechanical efficiency is then highly expected in elastomers. In this work, mechanically tunable flexoelectricity in DE is verified with theoretical analysis and experiments. A model is developed to study the mechanism of elastomers under pre-stretch. Experiment verification is applied by measuring the transverse flexoelectric coefficients of polydimethylsiloxane. Flexoelectric coefficient increases with the increase in stretch by one order of magnitude. This work opens up an avenue for tunable flexoelectric applications with stretchable dielectric materials.
Air film evolution during droplet impact onto a solid surface
Authors: Fu Zunru , Jin Haichuan , Zhang Jun , Xue Tianyou , Wen Dongsheng
Published: September 2021

Recent years see increasing studies of air entrapment during droplet impacting on a solid surface with many results. The dynamics of trapped air film during a droplet impact on a solid surface is investigated in this work by the phase field method in combination with a dynamic contact angle (DCA) model. The DCA model is established experimentally by capturing the droplet dynamics in analogy to the entrapped air evolution. By using the DCA model as the input, the simulation can accurately reproduce the experimental results. The effects of droplet viscosity and surface tension on the dynamics of the air film are then studied, and three possible regimes are identified, demarcated by an effective Ohnesorge number (Ohe). Regime 1 is the case where no daughter droplet is generated and the air bubble is always attached to the substrate, corresponding to the classical case at a high Ohe number (Ohe > 0.073). Regime 3 is a newly discovered regime in this work where a daughter droplet is generated and the air bubble is always detached from the substrate, corresponding to a low Ohe number (Ohe < 0.019) due to combined strong surface tension and vortex effects. Regime 2 is for moderate Ohe numbers where a daughter droplet is generated and the air bubble can either detach from or attach to the substrate. Different from conventional thought that the detachment in this regime is decided by a static contact angle, the DCA plays a leading role in determining the volume ratio of the daughter droplet to the gas bubble, and the combined effects determine the fate of the bubble. Such finding provides better insight on the entrapped air dynamics upon droplet impacting on a solid surface, an area of high engineering importance.
Flow instabilities and heat transfer in a differentially heated cavity placed at varying inclination angles: Non-intrusive measurements
Authors: Kishor Vimal , Singh Suneet , Srivastava Atul
Published: September 2021

We report the non-intrusive investigation of the dependence of buoyancy-driven flow instabilities on the orientation angle of a differentially heated cavity of aspect ratio three. The cavity orientation angles considered are 60° and 30°. While moving from 60° to 30°, the cavity is inclined toward its stable configuration, wherein convection reduces. Flow instabilities have been captured through the spectral analysis of the transient history of temperature distribution recorded in a completely non-intrusive manner using a Mach–Zehnder interferometer. By virtue of the fact that in such configurations, corners of the cavity are the most active regions with regard to the interaction of buoyancy-driven fluid with the cavity walls, and the flow behavior is centrosymmetric (diagonal symmetry), the flow field in the top two corners of the cavity has been mapped. The spatio-temporally resolved interferometric measurements identified two distinct frequencies for cavity inclination angle (θ) of 60°. These two frequencies correspond to two different flow instabilities, namely, the Tollmien–Schlichting (TS) and gravity wave-induced instabilities. As the cavity is further inclined toward 30°, the instability in the boundary layer, i.e., the TS instability, ceases to exist, and only the gravity wave-induced instability is observed. The dependence of flow instabilities on cavity orientation angle is explained on the basis of interferometry-based measurements made in the form of interferograms and the corresponding whole field maps of temperature contours. The convective flow field in the differentially heated cavity has also been qualitatively captured using smoke visualization to provide direct support to interferometric measurements.
Photon-number squeezing in nano- and microlasers
Authors: Carroll Mark Anthony , D'Alessandro Giampaolo , Lippi Gian Luca , Oppo Gian-Luca , Papoff Francesco
Published: September 2021

Based on theoretical predictions on the appearance of antibunching before the laser threshold at the nano- and microscale, we analyze the amount of photon-number squeezing naturally produced in the laser emission. Up to 3 dB photon number noise reduction is obtained in comparison with the coherent emission, with output power in the range of pW and with negligible effects due to pump fluctuations. The scheme requires a moderately high Q cavity and holds promise for the construction of a simple and effective photon-number squeezed source.
Experimental investigation into fluid–structure interaction of cavitating flow
Authors: Liu Yunqing , Huang Biao , Zhang Hanzhe , Wu Qin , Wang Guoyu
Published: September 2021

The objective of this paper is to study flow-induced vibration in cavitating flow around a steel stainless hydrofoil with the experimental and dynamic mode decomposition (DMD) method. A synchronized measured system consisting of a high-speed camera, lift measurement, and laser Doppler vibrometer is used to observe the cavitation structures, survey the vibrations, and measure the force. The hydrodynamic force and vibration velocity fluctuate most sharply in the cloud cavitation stage among all the cavitation regimes due to the unsteady cloud cavity, corresponding to the largest square root of normal distribution in the cloud cavitation in the analysis of statistic nature. Cavity shedding frequency, system-related frequency, and trailing edge vortex shedding frequency are observed in the vibration velocity frequency spectrum for the whole range of cavitation numbers. Cavity frequency dominates the structure response in the cloud cavitation regime. Two primary shedding mechanisms, re-entrant jet, and shockwave mechanism are identified for the cloud cavitation. The vibration velocity induced by the re-entrant jet mechanism is lower amplitude and larger frequency, while that induced by the shockwave mechanism is higher amplitude and smaller frequency due to the intense collapse of cloud cavity and rapid collapse of the attached cavity. Two peak bands related to the re-entrant jet development frequency and small-scale cavity shedding frequency are identified for the shockwave mechanism with DMD method.
Effect of the rotor blade installation angle on the structure-borne noise generated by adjustable-blade axial-flow fans
Authors: Sun Lihui , An Chunguo , Wang Nini , Zhe Chuntian , Wang Lin , He Suoying , Gao Ming
Published: September 2021

The effect of rotor blade installation angle on the structure-borne noise of adjustable-blade axial-flow fans is analyzed based on the fluid–solid coupling method. The co-simulation environment ANSYS Workbench is adopted to perform one-way fluid–solid coupling analysis. Following this, the properties of the flow field and noise field with different installation angles are simulated. The flow field simulation results reported significant vorticity near the rotor and stator, and a larger installation angle may cause higher pressure fluctuation. The sound field results showed that the frequency spectrum characteristics for the sound pressure level and the sound power level are almost the same while the installation angle changes from −8° to 8°, and the peaks of frequency spectrum occur at the blade passing frequency and its harmonics. The total sound pressure level (TSPL) and the total sound power level (TPWL) all show increasing trends ranging from −8° to +8°. The maxima of TSPL and TPWL reach 134.1 and 176 dB, while their minima reach 123.1 and 163 dB, respectively. Thus, reduction of the installation angle can reduce the structure-borne noise. Besides, the structure-borne noise generated by adjustable-blade axial-flow fans is low-frequency noise, which lies in the range of 0–500 Hz.
Review of Scientific Instruments New Products
Authors: Mandelis Andreas
Published: September 2021

In order to supplement manufacturers’ information, this department will welcome the submission by our readers of brief communications reporting measurements on the physical properties of materials, which supersede earlier data or suggest new research applications.
Embryo structure reorganisation reduces the probability of apoptosis in preimplantation mouse embryos
Authors: Winiarczyk Dawid , Piliszek Anna , Sampino Silvestre , Lukaszewicz Marek , Modliński Jacek Andrzej
Published: September 2021

Programmed cell death plays a key role in mammalian development because the morphological events of an organism’s formation are dependent on apoptosis. In the mouse development, the first apoptotic waves occur physiologically at the blastocyst stage. Cell number and the mean nucleus to cytoplasm (N/C) ratio increase exponentially throughout subsequent embryo cleavages, while cell volume concurrently decreases from the zygote to blastocyst stage. In this study we tested the hypothesis that reorganisation of the embryo structure by manipulating cell number, the N/C ratio and the cell volume of 2-cell embryos may result in the earlier and more frequent occurrence of apoptosis. The results indicate that doubling (‘Aggregates’ group) or halving (‘Embryos 1/2’ group) the initial cell number and modifying embryo volume, ploidy (‘Embryos 4n’ group) and the N/C ratio (‘Embryos 2/1’ group) reduce the probability of apoptosis in the resulting embryos. There was a higher probability of apoptosis in the inner cell mass of the blastocyst, but apoptotic cells were never observed at the morula stage in any of the experimental groups. Thus, manipulation of cell number, embryo volume, the N/C ratio and ploidy cause subtle changes in the occurrence of apoptosis, although these are mostly dependent on embryo stage and cell lineage (trophectoderm or inner cell mass), which have the greatest effect on the probability of apoptosis.
High-impact innovations for high-salinity membrane desalination
Authors: Dudchenko Alexander V. , Bartholomew Timothy V. , Mauter Meagan S.
Published: September 2021

Significance

Researchers lack the tools for quantitatively evaluating the impact of their research on technology costs, especially when those technologies comprise multiple components or when the component costs are highly uncertain. We propose a suite of tools to aid in evaluating technology platforms, setting system- and component-level research targets and identifying high-impact innovation trajectories. These tools are applicable to any technology composed of multiple components whose performance or cost will benefit from innovation, but they are especially valuable for membrane systems in which the high interdependence in components amplifies or dampens the effects of innovation in nonintuitive ways.
Engineering Li/Na selectivity in 12-Crown-4–functionalized polymer membranes
Authors: Warnock Samuel J. , Sujanani Rahul , Zofchak Everett S. , Zhao Shou , Dilenschneider Theodore J. , Hanson Kalin G. , Mukherjee Sanjoy , Ganesan Venkat , Freeman Benny D. , Abu-Omar Mahdi M. , Bates Christopher M.
Published: September 2021

Significance

Lithium is a key ingredient in batteries, which are integral components of next-generation automobiles, airplanes, grid energy storage, and electronic devices. Unfortunately, lithium extraction from natural sources is laborious, slow, and costly, motivating the search for more efficient isolation techniques. While polymeric membranes could reduce the cost of lithium recovery, current membrane materials lack sufficient lithium-ion selectivity. To address this challenge, we introduce a class of polymeric membranes that incorporate ion binding sites, which significantly increases the transport selectivity of LiCl over NaCl. These studies provide guidelines and practical considerations for incorporating specific interactants into polymers that mediate selective ion transport.
Interaction-based ion selectivity exhibited by self-assembled, cross-linked zwitterionic copolymer membranes
Authors: Lounder Samuel J. , Asatekin Ayse
Published: September 2021

Significance

The separation of ions is challenging yet crucial for providing access to safe water resources as well as recovering valuable ions from water and wastewater. Yet, membranes rarely exhibit selectivity between ions of similar charge and size. We demonstrate that membranes, prepared by a fully scalable method that uses self-assembling zwitterionic copolymers, exhibit exceptional selectivity between salt anions of similar size and charge. We show that this unusual capability is derived from selective zwitterion–ion interactions occurring within the nanochannels, similarly to biological ion channels. We further demonstrate these membranes exhibit Cl
−
/F
−
permselectivity more than twice the values reported in previous studies, with applications in treating groundwater streams to prevent fluorosis and in wastewater treatment.
Tunable membranes incorporating artificial water channels for high-performance brackish/low-salinity water reverse osmosis desalination
Authors: Di Vincenzo Maria , Tiraferri Alberto , Musteata Valentina-Elena , Chisca Stefan , Deleanu Mihai , Ricceri Francesco , Cot Didier , Nunes Suzana P. , Barboiu Mihail
Published: September 2021

Significance

Inspired by biological models, artificial water channels can be used to overcome the permeability/selectivity trade-off of traditional desalination membranes. We demonstrate that rational incorporation of I-quartet artificial water channels in composite polyamide membranes synthesized via interfacial polymerization, provides defect-free biomimetic membranes with intrinsic water-to-salt permeability on the operational brackish-water reverse osmosis (BWRO)/tap water reverse osmosis (TWRO) desalination pressure and medium/low-salinity conditions.
Zeolite-like performance for xylene isomer purification using polymer-derived carbon membranes
Authors: Ma Yao , Bruno Nicholas C. , Zhang Fengyi , Finn M. G. , Lively Ryan P.
Published: September 2021

Significance

Xylenes are essential feedstocks for manufacturing packaging materials, versatile chemicals, industrial solvents, etc. The purification of xylene isomers is one of the most important yet energy-intensive organic mixture separations in the chemical industry. We achieved the separation of xylene isomers using carbon molecular sieve (CMS) membranes derived from a spirobifluorene-based polymer of intrinsic microporosity (PIM-SBF), which could potentially reduce the energy consumption, carbon emissions, and equipment footprint. CMS membranes are solvent- and temperature-resistant materials that can withstand high transmembrane pressures when fabricated into the form of hollow fibers. The new CMS membrane produced here shows competitive performance with state-of-the-art zeolites under high xylene loadings, and its development has provided fundamental insight and guidance into the manipulation of CMS pore structure.
Mobile Phone and Internet use among People who Inject Drugs: Implications for Mobile Health Interventions
Authors: Ozga Jenny E. , Paquette Catherine , Syvertsen Jennifer L. , Pollini Robin A.
Published: September 2021

Background: Mobile health (mHealth) interventions have the potential to improve substance use treatment engagement and outcomes, and to reduce risk behaviors among people who inject drugs (PWID). However, there are few studies assessing mobile technology use among PWID and none have investigated continuity of mobile phone use. Methods: We surveyed 494 PWID. We used bivariate (independent-sample t- and chi-square tests) and multivariate (logistic regression) analyses to determine whether mobile phone and/or internet use differed as a function of participant- and/or injection-related characteristics. Results: Most participants (77%) had a mobile phone, with 67% having a phone that was free of charge. Participants with a phone were significantly less likely to be homeless (AOR = 0.28), to have shared syringes (AOR = 0.53), and to have reused syringes (AOR = 0.26) in the past 3 months. We observed high rates of phone and number turnover, with more than half reporting that they got a new phone (57%) and/or number (56%) at least once within the past 3 months. Most participants were familiar with using the internet (80% ever use), though participants who had ever used the internet were younger (AOR = 0.89), were less likely to be homeless (AOR = 0.38), were less likely to have shared syringes (AOR = 0.49), and were more likely to have injected methamphetamine by itself (AOR = 2.49) in the past 3 months. Conclusions: Overall, mobile technology and internet use was high among our sample of PWID. Several factors should be considered in recruiting diverse samples of PWID to minimize bias in mHealth study outcomes, including mobile phone access and protocol type (text- vs internet-based).