bluuebunny/crossref_metadata_2025 huggingface dataset:
A study of material removal and surface characteristics in micro‐electrical discharge machining of carbon fiber‐reinforced plastics
Authors: Dutta Hrishikesh , Debnath Kishore , Sarma Deba Kumar
Published: March 2019

This article presents micro electrical discharge machining (μEDM) of carbon fiber‐reinforced plastics (CFRP) with rotating tool electrode and assisting electrode (AE). The experimental investigation majorly focused on establishing the mechanisms of material removal and surface integrity of the machined blind holes. Taguchi and regression analysis were carried out to assess the material removal rate (MRR). Analysis of variance (ANOVA) was applied to understand the significance of input parameters and their contribution toward achieving maximum MRR. The surface integrity of the machined hole and damage modes of composite constituents were also examined through micrographic images. The experiments were carried out varying the voltage, pulse duration, and tool speed at three levels. The investigations showed that μEDM process can be applied for fabricating micro holes in CFRP if assisting electrode (AE) is used to initiate the spark. From the analysis of variance (ANOVA), it was observed that the percentage contribution of voltage, pulse duration, and tool rotational speed on MRR are 75.09, 5.20, and 16.09%, respectively. The optimal condition for the highest MRR was found to be V3/T1/S3 (voltage of 170 V, pulse duration of 10 μs, and tool speed of 800 rpm). The calculated value of MRR (341,264.94 μm3/s) at the optimum level of input parameters was found to be close to the experimental MRR (340,727 μm3/s). The percentage error between the experimental and calculated value of MRR at the optimum level is very low as 0.15%. This indicates that the developed statistical model is quite significant in predicting MRR during μEDM of CFRP. POLYM. COMPOS., 40:4033–4041, 2019. © 2019 Society of Plastics Engineers
Chorionic bump at 11 to 13 weeks' gestation: Prevalence and clinical significance
Authors: Sepulveda Waldo
Published: March 2019

Objective

To gather additional data on pregnancy outcome when a chorionic bump is detected at the time of the 11‐ to 13‐week scan.

Methods

The presence of a chorionic bump was prospectively recorded in a database of women presenting for their first‐trimester sonographic screening. Clinically relevant information was obtained by reviewing ultrasound reports and medical records or contacting the referring obstetrician or the parents themselves.

Results

During a 4.5‐year study period from June 2014 to December 2018, a chorionic bump was identified in 23 out of 3375 pregnancies, for a prevalence of 1/147 or 0.7%. All women were asymptomatic at the time of evaluation. The chorionic bump was single in 21 (91%) cases, located in the central part of the placenta in 17 (74%) cases, and the median largest diameter was 20 mm (range, 10‐43). Although the placenta was low‐lying in 14 (61%) cases, all but one patient had a normally located placenta at the midtrimester anatomy scan. With the exception of one pregnancy complicated with trisomy 21, the outcome was universally good.

Conclusion

Our experience suggests that a chorionic bump detected during the 11‐ to 13‐week scan is usually a transient, is incidental finding, and probably has no clinical significance.
Heterogeneity in the treatment of bloodstream infections identified from antibiotic exposure mapping
Authors: Caffrey Aisling R. , Babcock Zachary R. , Lopes Vrishali V. , Timbrook Tristan T. , LaPlante Kerry L.
Published: March 2019

Purpose

As changes in antibiotic therapy are common, intent‐to‐treat and definitive therapy exposure definitions in infectious disease clinical trials and observational studies may not accurately reflect all antibiotics received over the course of the infection. Therefore, we sought to describe changes in antibiotic therapy and unique treatment patterns among patients with bacteremia.

Methods

We conducted a retrospective cohort study of hospitalizations from Veterans Affairs (VA) Medical Centers (January 2002‐September 2015) and community hospitals (de‐identified Optum Clinformatics DataMart with matched Premier Hospital data; October 2009‐March 2013). In the VA population, antibiotic exposures were mapped from the culture collection date among those with positive Staphylococcus aureus cultures. In the Optum‐Premier population, exposures were mapped from the admission date among those with a primary diagnosis of bacteremia.

Results

Our study included 50 467 bacteremia admissions, with only 14% of admissions having the same treatment pattern as another admission. For every 100 bacteremia admissions, 89 had changes in antibiotic therapy. For every 100 bacteremia admissions with changes in therapy, 95 had unique antibiotic treatment patterns. These findings were consistent in both populations, over time, and among different facilities within study populations. The median time to first therapy change was 2 days after initial therapy, with a median of three changes.

Conclusions

Changes in antibiotic therapy for bloodstream infections were nearly universal regardless of hospital setting. Based on our findings, common antibiotic exposure definitions of intent‐to‐treat and definitive therapy would misclassify exposure in 86% of admissions, which highlights the need for better operational definitions of exposure in infectious diseases research.
The relation between falls and medication use among elderly in assisted living facilities
Authors: Hamza Sarah Ahmed , Adly Nermien Naim , Abdelrahman Ekramy Essa , Fouad Ibrahim Mohamed
Published: March 2019

Purpose

Many elderly are concerned about falling transfer to assisted living facilities (ALF). Previous literatures studied the medication use and falls in the community, hospitals, or nursing homes, with scanty data about ALF. Therefore, the aim of the current case‐control study was to assess the relation between medication use and falls among elderly in ALF.

Methods

A matched case‐control study was conducted. The study was conducted in ALF in Cairo, Egypt. The study participants were 188 individuals; they were subdivided into two groups: fallers and nonfallers; timed up and go test (TUGT) was performed by all subjects. Medication data were collected according to the fall risk‐increasing drugs list and the list of drugs that cause or worsen orthostatism. Other fall risk factors, as suggested by American Geriatric Society, were assessed.

Results

The use of vasodilators, diuretics, alpha blockers, opioids, antipsychotics, and sedative hypnotics were more common in fallers than in nonfallers (P < 0.001, P = 0.03, P < 0.001, P = 0.013, P < 0.001, and P < 0.001, respectively). Vasodilators, alpha blockers, and antipsychotics were significant predictors of falls even after adjustment for the possible confounding factors. Vasodilators, alpha blockers, opioids, sedative hypnotics, and recent dose changes in oral hypoglycemics were significant predictors of higher TUGT after adjustment for the possible confounding factors.

Conclusion

The current study supported the risk of psychotropic and cardiovascular medications, with especial emphasis on vasodilators, alpha blockers, and antipsychotics, with raising concern about opioids, sedative hypnotics, and recent dose change in oral hypoglycemics.
Application of distributed temperature sensing for mountain permafrost mapping
Authors: Harrington Jordan S. , Hayashi Masaki
Published: March 2019

Permafrost distribution in mountains is typically more heterogeneous relative to low‐relief environments due to greater variability in the factors controlling the ground thermal regime, such as topography, snow depth, and sediment grain size (e.g., coarse blocks). Measuring and understanding the geothermal variability in high mountains remains challenging due to logistical constraints. This study presents one of the first applications of distributed temperature sensing (DTS) in periglacial environments to measure ground surface temperatures in a mountain permafrost area at much higher spatial resolution than possible with conventional methods using discrete temperature sensors. DTS measures temperature along a fibre‐optic cable at high spatial resolution (i.e., ≤ 1 m). Its use can be limited by power supply and calibration requirements, although recent methodological developments have relaxed some of these restrictions. Spatially continuous DTS measurements at a studied rock glacier provided greater resolution of geothermal variability and facilitated the interpretation of bottom temperature of snowpack data to map patchy permafrost distribution. This research highlights the potential for DTS to be a useful tool for permafrost mapping, ground thermal regime interpretation, conceptual geothermal model development, and numerical model evaluation in areas of heterogeneous mountain permafrost.
Oxygen saturations and neurodevelopmental outcomes in single ventricle heart disease
Authors: Wolfe Kelly R. , Brinton John , Di Maria Michael V. , Meier Maxene , Liptzin Deborah R.
Published: March 2019

Objectives

To evaluate whether the degree of hypoxemia following stage‐I and stage‐II palliative surgeries predicts neurodevelopmental outcomes at 14 months of age in children with single ventricle congenital heart disease (SVCHD).

Design

We analyzed longitudinal data from two Pediatric Heart Network (PHN) randomized controlled trials, with a total of 328 subjects. Oxygen saturations, measured via pulse oximetry, at time of discharge from stage‐I and stage‐II surgeries were the primary predictors of interest, and Bayley Scales of Infant Development‐II (BSID‐II) scores at 14 months old were the primary outcome measure. Relevant covariates from previously‐published PHN studies were also included in regression models.

Results

Oxygen saturations at time of discharge from stage‐I and stage‐II surgeries were not related to BSID‐II scores. Having one or more oxygen saturation measurements below 80% was also not associated with BSID‐II scores, and neither was change in oxygen saturations over time. These relationships were not altered by inclusion of relevant covariates.

Conclusions

In this large cohort of children with SVCHD, oxygen saturations post‐stage‐I and post‐stage‐II palliation surgeries as measured via pulse oximetry were not associated with neurodevelopmental outcomes at 14 months of age. The relationship between oxygen saturations and neurodevelopment in SVCHD is likely complex, and neurodevelopment is known to be affected by a number of factors. Pulse oximetry may also be an insufficient proxy for cerebral oxygen delivery. Clinically, pulse oximetry readings during the interstage and post‐stage‐II surgery periods are not a reliable predictor of future neurodevelopmental risk.
In Situ Observation of the Degradation in Multi‐Crystalline Si Solar Cells by Electroluminescence
Authors: Mchedlidze Teimuraz , Alam Md Mahabubul , Herguth Axel , Weber Joerg
Published: March 2019

Carrier‐induced efficiency degradation of multi‐crystalline Si (mc‐Si) solar cells is studied in situ by detecting the electroluminescence (EL) from the cells. Series of spatially resolved EL images of the cells during constant forward current operation at low (24 °C) and at elevated (70 °C) temperatures are recorded. The degradation induced changes in the open circuit voltage correlate well with changes in the EL intensities. The similarity of light‐induced and carrier‐induced degradation processes for mc‐Si cells is confirmed. The correlation of the degradation with the material structure is analyzed. The degradation appears to correlate with the density of structural defects in the cells. The results verify that EL images present a powerful tool for in situ analyses of mc‐Si cell degradation processes in various cell structures with a broad variety of biasing and temperature conditions.
Role of the Short‐Range Order in Amorphous Oxide on MoS2/a‐SiO2 and MoS2/a‐HfO2 Interfaces
Authors: Park Jaehong , Yeu In Won , Han Gyuseung , Hwang Cheol Seong , Choi Jung‐Hae
Published: March 2019

The interface structures between MoS2 and amorphous oxides of SiO2 and HfO2 (MoS2/a‐SiO2 and MoS2/a‐HfO2) are investigated through ab‐initio molecular dynamics simulations. The intrinsic short‐range order (SRO) of the amorphous oxide, such as the bond length, coordination number, and connectivity of the oxide polyhedron, is crucial in the interfacial properties. The amorphous SiO2 showing the strict SRO induces a strong interaction with MoS2 and forms interfacial bonds of Si–S, resulting in a significantly increased effective mass of MoS2. By contrast, the amorphous HfO2 has more flexible SRO and weakly interacts with MoS2, which explains the maintenance of the band dispersion and effective mass of MoS2 in contact with amorphous HfO2. These calculation results indicate a possible mechanism of the higher mobility of MoS2/a‐HfO2 over MoS2/a‐SiO2 by accounting for the interfacial atomic structure.
Context and Implications Document for: The effectiveness of computer‐assisted pronunciation training: A meta‐analysis
Authors: Mahdi Hassan Saleh , Khateeb Ahmed Abdulateef Al
Published: March 2019

This guide accompanies the following article: Mahdi, H. S. & Al‐Khateeb, A. A., The effectiveness of computer‐assisted pronunciation training: A meta‐analysis, Review of Education, https://doi.org/10.1002/rev3.3165
The effectiveness of computer‐assisted pronunciation training: A meta‐analysis
Authors: Mahdi Hassan Saleh , Al Khateeb Ahmed Abdulateef
Published: March 2019

Computers are used in almost all aspects of language learning and have also created numerous opportunities in this area. This study aims to examine the overall effectiveness of using a computer in pronunciation learning and training. A meta‐analysis of studies was conducted, which compared the outcomes of students learning the pronunciation of a foreign language (FL) using a computer with the results from those learning pronunciation based on traditional methods of teaching. This meta‐analysis examined how effect sizes varied depending on the learners’ age, learners’ target language proficiency, features of pronunciation, educational level, settings, treatment duration, and assessment tasks. This meta‐analysis examined the effect of using a computer on pronunciation learning by reviewing 20 studies involving 1014 participants. The findings of the meta‐analysis suggest that computer‐assisted training has a positive effect on FL pronunciation (d = 0.68), and is equally effective for both young and adult learners, but more effective for beginner and intermediate learners than advanced learners. The studies also suggest that computer‐assisted pronunciation training (CAPT) is more beneficial for university students than for school students. However, caution has to be exercised in interpreting the results. The small number of studies, all of very low quality (most with fewer than 100 participants, conducted within the same institution using intervention‐related assessments) means that the evidence of effectiveness can only be indicative and not conclusive. More robust, large‐scale studies involving several institutions and using objective standardised tests would be needed for more conclusive results.
A simple method for sampling invertebrate drift in large rivers and boulder‐bed streams
Authors: Rosenfeld Jordan S. , Naman Sean M.
Published: March 2019

Sampling invertebrate drift in high‐gradient boulder‐bed channels or large turbulent rivers is challenging, because the traditional approach of driving stakes into the stream bed to secure drift nets may not work. We describe a simple method using a split wading rod to collect drift samples from the wadeable river margin or bank as an alternative method for rapid assessment of invertebrate drift when boat access is not possible. Pilot sampling in a large river shows that near‐shore drift samples collected with this approach are broadly similar to samples collected from the centre of the channel using more conventional methods, although our results suggest that depth and velocity effects may cause drift concentrations to be elevated closer to the bank.
Bioconjugated Carbon Dots for Delivery of siTnfαto Enhance Chondrogenesis of Mesenchymal Stem Cells by Suppression of Inflammation
Authors: Liu Jianwei , Jiang Tongmeng , Li Chun , Wu Yang , He Maolin , Zhao Jinmin , Zheng Li , Zhang Xingdong
Published: March 2019

Although a promising strategy, the mesenchymal stem cell (MSC)-based therapy of cartilage defects is sometimes accompanied with chronic inflammation during the remodeling status, which may hinder cartilage regeneration. During this process, the inflammatory cytokine tumor necrosis factor α (TNFα) plays an important role and may be a potential target. In this study, we investigated the effect of Tnfα RNA interference by introducing a functional and highly safe carbon dot (CD)-SMCC nanovector synthesized by bioconjugation of CDs with a protein crosslinker, sulfosuccinimidyl-4-(N-maleimidomethyl) cyclohexane-1-carboxylate (sulfo-SMCC), as the vehicle of the silenced TNFα (siTnfα) on chondrogenesis of MSCs. The results showed that CD-SMCC displayed intense fluorescence with well-dispersed and positively charged properties, which favored effective binding and delivering of siTnfα into the MSCs. CD-SMCC-siTnfα nanoformula also exhibited considerably high transfection efficiency and nearly no cytotoxicity, which is preferred over commercial polyethyleneimine. Interference of Tnfα by CD-SMCC-siTnfα markedly promoted the chondrogenesis of MSCs, as indicated by upregulating cartilage-specific markers. Furthermore, in vivo exploration indicated that CD-SMCC-siTnfα transfected MSCs accelerated cartilage regeneration. In conclusion, this study demonstrated that in combination with the novel CD-SMCC nanovector, targeting Tnfα may facilitate stem cell-based therapy of cartilage defects. Stem Cells Translational Medicine  2019;8:724&736
Coal Bed Methane Enhancement Techniques: A Review
Authors: Goraya Navroop Singh , Rajpoot Neetoo , Marriyappan Sivagnanam Balathanigaimani
Published: March 2019

Paper investigates the potential impact of Coalbed methane (CBM) in near present and future. CBM is a natural gas that mainly consists of methane present in physically adsorbed state on the surface of porous coal seam under geothermal pressure. CBM is a cleaner fuel which can be used in the transportation industry, conventional power generation, and many other ways. 50–60% of CBM recovery can be obtained under primary operations and enhancement techniques can increase recovery as high as 80%. Recovery enhancement can be made through temperature increase, pressure release or by selective adsorption in which an injection gas displace methane from coal surface. Recovery through the use of CO2, N2, CO2 & N2 mixture is discussed in detail. Underground coal gasification can be used to recover energy from methane depleted, unminable coal reservoirs and has many advantages over surface mining. CBM consists of both thermogenic and biogenic origin. Depleted CBM reservoirs are observed to produce methane even after recovery is done. Native naturally occurring microbes decomposes coal into methane which explains biogenic origin, through a series of reaction. Kinetics of these decomposition reaction could be escalated significantly through the injection of nutrients and genetically enhanced methanogens. These processes has a great potential and could provide a fossil fuel which is almost renewable as large amount of methane can be generated from small amount of coal.
Design of Organic Structure Directing Agents for Chiral Zeolite Beta A
Authors: Daeyaert Frits , Deem Michael W.
Published: March 2019

We have designed chiral organic structure directing agents (OSDAs) to direct the formation of enantiomerically enriched zeolite BEA. The in silico design was a combination of a multi‐objective scoring function with exhaustive and stochastic virtual combinatorial chemistry and de novo design algorithms. Importantly, the algorithms used directly consider the synthetic accessibility of the designed OSDAs. We have identified 175 putative OSDAs of which one enantiomer has a low stabilization energy in the P4122 enantiomorph of zeolite BEA and the mirror image enantiomer has a significantly less favorable stabilization energy. In addition, 42 of the designed compounds have a significantly less favorable stabilization energy in the competing BEB zeolite. Enantiomerically pure zeolite BEA is of interest for stereoselective separation and catalysis.
Oxygen‐Doped Porous Carbon Nanosheet for Efficient N2 Fixation to NH3 at Ambient Conditions
Authors: Chen Jiayin , Huang Hong , Xia Li , Xie Hongtao , Ji Lei , Wei Peipei , Zhao Runbo , Chen Hongyu , Asiri Abdullah M. , Sun Xuping
Published: March 2019

NH3 is one of the largest‐volume industrial chemicals synthesized in the world. It not only is a kind of important chemical base materials to produce fertilizers, plastics and explosives, but also can serve as a clean energy carrier with high hydrogen content for a sustainable energy supply. N2 is the most abundant gas in atmosphere, but its inert character caused by the strong triple bond, impedes itself from being converted to NH3. In nature, this shortcoming is overcome by biological N2 fixation utilizing nitrogenase enzymes. Industrially, fixation of N2‐to‐NH3 prevailingly depends on Haber‐Bosch process using Ru‐ or Fe‐based catalysts, but this process consumes large energy and emits heavy carbon which increases crisis of global warming.
Catalytic Synthesis of Hard/Soft Carbon Hybrids with Heteroatom Doping for Enhanced Sodium Storage
Authors: Liu Xu , Zhu Youyu , Liu Na , Chen Mingming , Wang Chengyang , Wang Xiaolei
Published: March 2019

Hard carbon shows a promising application for sodium storage but suffers from low electrochemical stability, which leads to poor rate capacity and cycle life. Here, we report a heteroatom‐doping hard/soft carbon hybrid prepared by easy oxidizing acid treatment and low temperature catalytic graphitization. The heteroatoms increase the sodium‐ion adsorption capability during slope region, showing an important contribution at high current. Besides, the introduction of oriented domains enhances the conductivity, as well as the heteroatom doping, and electrochemical stability of hard/soft carbon hybrids. What's more, these structure characteristics also benefit the stable storage of sodium ions, supported by a 74% increase in terms of reversible capacity. Thus, the electrochemical performance retains a fast and reversible capacity of 125 mAh⋅g−1 at high current density of 8 C.
Bioinspired Flexible Volatile Organic Compounds Sensor Based on Dynamic Surface Wrinkling with Dual‐Signal Response
Authors: Qu Chunyan , Wang Shuqi , Liu Lin , Bai Yuanyuan , Li Lianhui , Sun Fuqin , Hao Mingming , Li Tie , Lu Qifeng , Li Lili , Qin Sujie , Zhang Ting
Published: March 2019

Living systems can respond to external stimuli by dynamic interface changes. Moreover, natural wrinkle structures allow the surface to switch dynamically and reversibly from flat to rough in response to specific stimuli. Artificial wrinkle structures have been developed for applications such as optical devices, mechanical sensors, and microfluidic devices. However, chemical molecule‐triggered flexible sensors based on dynamic surface wrinkling have not been demonstrated. Inspired by human skin wrinkling, herein, a volatile organic compound (VOC)‐responsive flexible sensor with a switchable dual‐signal response (transparency and resistance) is achieved based on a multilayered Ag nanowire (AgNW)/SiOx/polydimethylsiloxane (PDMS) film. Wrinkle structures can form dynamically in response to VOC vapors (such as ethanol, toluene, acetone, formaldehyde, and methanol) due to the instability of the multilayer induced by their different swelling capabilities. By controlling the modulus of PDMS and the thickness of the SiOx layer, tunable sensitivities in resistance and transparency of the device are achieved. Additionally, the proximity mechanism of the solubility parameter is proposed, which explains the high selectivity of the device toward ethanol vapor compared with that of other VOCs well. This stimuli‐responsive sensor exhibits the dynamic visual feedback and the quantitative electrical signal, which provide a novel approach for developing smart flexible electronics.
RETRACTED: Supramolecular Nanotube Reactors for Production of Imine Polymers with Controlled Conformation, Size, and Chirality
Authors: Kameta Naohiro , Ding Wuxiao
Published: March 2019

A series of supramolecular nanotubes with inner diameters of 1, 4, 9, 12, 16, and 29 nm are prepared from amino acid lipids. The hydrophobic channels of the nanotubes act as reactors for the formation of imine polymers by not only effectively encapsulating the benzaldehyde and diacetyleneamine precursors of the imine monomers but also markedly accelerating imine formation. The nanotube inner diameter determines whether the imine monomers self‐assemble into nanoparticles, nanotapes, nanocoils, or twisted nanofibers in the channels. UV‐induced polymerization of the diacetylene units in the imine nanostructures followed by decomposition of the nanotubes into molecular dispersions of the constituent amino acid lipids results in expulsion of the polymerized imine nanostructures with retained conformation. The isolated nanocoils and twisted nanofibers retain the helicity and circular dichroism induced by the nanotubes, which exhibits supramolecular chirality, even though the components of the imine monomers are achiral. These supramolecular nanotubes with tunable diameters and functionalizable surfaces can be expected to be useful for the production of polymers with controlled conformation, size, and chirality without the need for rational design or chemical modification of the monomers or optimization of the polymerization conditions.
Predicting process performance: A white‐box approach based on process models
Authors: Verenich Ilya , Dumas Marlon , La Rosa Marcello , Nguyen Hoang
Published: March 2019

Predictive business process monitoring methods exploit historical process execution logs to provide predictions about running instances of a process. These predictions enable process workers and managers to preempt performance issues or compliance violations. A number of approaches have been proposed to predict quantitative process performance indicators for running instances of a process, including remaining cycle time, cost, or probability of deadline violation. However, these approaches adopt a black‐box approach, insofar as they predict a single scalar value without decomposing this prediction into more elementary components. In this paper, we propose a white‐box approach to predict performance indicators of running process instances. The key idea is to first predict the performance indicator at the level of activities and then to aggregate these predictions at the level of a process instance by means of flow analysis techniques. The paper develops this idea in the context of predicting the remaining cycle time of ongoing process instances. The proposed approach has been evaluated on real‐life event logs and compared against several baselines.
Reconstructing Dual‐Induced {0 0 1} Facets Bismuth Oxychloride Nanosheets Heterostructures: An Effective Strategy to Promote Photocatalytic Oxygen Evolution
Authors: Ning Shangbo , Shi Xiaoqi , Zhang Hongwen , Lin Huaxiang , Zhang Zizhong , Long Jinlin , Li Yi , Wang Xuxu
Published: March 2019

Sunlight‐driven photocatalytic water splitting to generate oxygen (O2) is a promising approach for utilizing solar energy. Herein, direct Z‐scheme heterostructure photocatalysts composed of ultrathin Bi3O4Cl and BiOCl nanosheets are rationally fabricated via alkaline chemical etching and solvent exfoliation for O2 evolution under visible light. With AgNO3 and FeCl3 as the electron scavenger, the optimized ultrathin Bi3O4Cl/BiOCl exhibits prominent photocatalytic activity for O2 production under visible‐light illumination and the production rate (Fe3+: 58.6 µmol g−1 h−1) is much higher than the nanocrystal heterostructure (Fe3+: 28.5 µmol g−1 h−1). This ultrathin heterostructure system can efficiently transfer the electrons, which leads to a considerable improvement in the photocatalytic performance. Due to the suitable band edge potentials and the intense electronic interaction between two‐dimensional (2D) Bi3O4Cl and 2D BiOCl, as confirmed by theoretical computations, photoluminescence, and photoelectricity tests, the ultrathin heterojunction with an internal electric field has a highly remarkable charge transfer. The intimate interface contact and {0 0 1} facets effect promote the high photocatalytic performance of the ultrathin Bi3O4Cl/BiOCl heterostructure.
One‐Step Solid‐Phase Synthesis of 2D Ultrathin CdS Nanosheets for Enhanced Visible‐Light Photocatalytic Hydrogen Evolution
Authors: Cheng Lei , Zhang Dainan , Liao Yulong , Zhang Huaiwu , Xiang Quanjun
Published: March 2019

Photocatalysts with 2D ultrathin nanosheet structures are gradually attracting significant interest from researchers because of their excellent photoelectric and physicochemical properties. However, the efficient fabrication of 2D CdS nanosheets with high crystallinity and ultrathin thickness still faces huge challenges. In this work, 2D ultrathin CdS nanosheets are synthesized through a simple one‐step solid‐phase strategy using CdSO4 · 8/3H2O as precursors in the CH4N2S atmosphere. The 2D ultrathin CdS nanosheet obtained by calcining at 300 °C for 4 h shows superior photocatalytic activity: the photocatalytic rate of hydrogen generation reaches 149.67 μmol h−1, and the corresponding apparent quantum efficiency is 36.7% at 450 nm. The enhanced photocatalytic activity and excellent photocatalytic stability are realized through the high crystallinity and ultrathin 2D nanosheet structure of CdS, which provide a high surface‐to‐volume ratio and enriched active adsorption sites. The 2D ultrathin nanosheet structure prevents the surface sulfide ions from being oxidized because of the extremely short interface distances and photocatalytic carrier transport, resulting in effective photocorrosion inhibition. Controlled experiments also show that the precursors ZnSO4 · 7H2O and Cd(Ac)2 · 2H2O are converted to 2D ZnS and CdS nanosheets through the one‐step solid‐phase method, illustrating that this simple one‐step solid‐phase strategy can be extended to the fabrication of other metal sulfide photocatalysts with 2D nanostructures.
Precipitation Behavior of Large Primary Carbides in Cast H13 Steel
Authors: Huang Yu , Cheng Guoguang , Li Shijian , Dai Weixing
Published: March 2019

The large primary carbides precipitated during solidification can significantly reduce the performance of H13 steel. To better inhibit the formation of primary carbides, it is necessary to obtain the precipitation mechanism of primary carbides in H13 steel. First, an electronic probe microanalyzer (EPMA) is used to analyze the microsegregation of alloying elements in the last‐to‐solidify region. The enrichment of elemental V, Mo, Cr, and C in the last‐to‐solidify region is the main reason for the formation of primary carbides. The number density, size, and morphology of the carbides in a two‐dimensional (2D) observation are obtained through an automatic inclusion analysis system. A non‐aqueous electrolysis method is used to show the three‐dimensional (3D) morphology of the primary carbides. There is a large difference between the 2D and 3D primary carbide observation. Finally, the precipitation mechanism and process of carbides during solidification are calculated with the Thermo‐Calc thermodynamic software, and the calculated results are in keeping with the experimental observation.
Crystallization of Short‐Chain Amylose: Effect of the Precipitant
Authors: Huang Zhaohua , Zeng Zhilu , Gao Yifang , Liu Chengmei , Wu Jianyong , Hu Xiuting
Published: March 2019

The effects of ethanol and polyethylene glycol (PEG) on crystallization of short‐chain amylose are investigated. In the absence of precipitants, the yield of short‐chain amylose precipitate is 38.8%, while the presence of ethanol and PEG increases the yield to 45.1% and 54.7%, respectively. Moreover, the crystallinity of the precipitate obtained without the precipitants is 45.4%, while the presence of ethanol and PEG increases the crystallinity to 50.4% and 48.6%, respectively. In the absence of precipitants, the precipitate shows B‐type crystallinity and is spherical with the size <1 µm. In the presence of ethanol, the precipitate displays A‐type crystallinity and an elongated platelet shape with the length >1 µm. The precipitate obtained in the presence of PEG is also B‐type and spherical but is smaller than the precipitate obtained in the absence of precipitants. These results suggest that ethanol and PEG significantly affect crystallization of short‐chain amylose in different ways.
Exploring Economic Diversity and Inequity Through Picture Books
Authors: Quast Erin , Bazemore‐Bertrand Shamaine
Published: March 2019

A significant percentage of students have families from lower socioeconomic status backgrounds, yet the experiences and practices of such students are often not reflected in the curriculum. To create more equitable literacy learning environments, students need opportunities to explore economic diversity and to challenge harmful discourses about people experiencing economic hardship. The authors discuss how picture books can be used in elementary classrooms to reflect economic diversity and to facilitate critical classroom conversations on economic hardship. The authors also discuss the importance of teachers attending to students’ economic backgrounds, highlight promising trends in contemporary picture books on economic hardship, and provide critical considerations for teachers when planning for student dialogue on economic inequity.
Reflection on opportunities for high penetration of renewable energy in China
Authors: Li Qiwei , Zhang Jiaxuan , Chen Jiahui , Lu Xi
Published: March 2019

Increasing penetration of renewable energy (RE) is expected to be an essential component for China to achieve goals in mitigating global climate change and domestic air pollution. Although China has experienced rapid growth of RE over the past two decades, problems restricting further development of RE occur, among which high curtailment rate of wind and solar power raises great attention. This paper reflects on the challenges and opportunities of high penetration of RE from both technical and market perspectives in China based on literature review. In particular, it emphasizes technical options to address the inherent variability of RE from three layers, namely using interconnected geographically dispersed sources to reduce random variance, increasing storage capacity to deal with minute‐to‐day imbalance, and applying backup capacity for seasonally mismatch. From the market perspective, the paper analyzes the needs of shifting from central planning to market‐based dispatch, introducing markets for ancillary services, and having a larger and more precise market. Meanwhile, our paper further points out that opportunities for high RE integration may rely on deep electrification of transportation and building sectors, which are also the foci for future air pollution control in China. It is feasible for China to achieve a high if not 100% RE system, but first these technical and market challenges have to be addressed in the process of adjusting its energy structure.

This article is categorized under:

Energy Systems Analysis > Climate and Environment

Energy and Climate > Climate and Environment
On sufficient dimension reduction for functional data: Inverse moment‐based methods
Authors: Song Jun
Published: March 2019

In this article, we present methods of sufficient dimension reduction (SDR) for functional data and organize them in a unified framework. The current existing methods for multivariate, functional data, functional response, and nonlinear SDR for functional data are illustrated in a way that they are naturally generalized. If a covariance operator is defined on an infinite‐dimensional space, the inverse of it is not bounded. Thus it is difficult to estimate and even impossible to apply the conventional results. We present solutions to resolve the inverse issue for the methods of functional SDR. Then we explain the functional SDR methods in three different scenarios: scalar‐on‐function, function‐on‐function, nonlinear SDR for function‐on‐function problem.

This article is categorized under:

Data: Types and Structure > Streaming data

Statistical and Graphical Methods of Data Analysis > Dimension Reduction

Statistical Learning and Exploratory Methods of the Data Sciences > Clustering and Classification

Data: Types and Structure > Time Series, Stochastic Processes, and Functional Data
Biology Involves Regulatory Control of Physical–Chemical Energetic Processes
Authors: Bolton Derek , Gillett Grant
Published: March 2019

As Engel saw, we will never make sense of psychosocial factors and their influence on health and disease while there is an underlying assumption that only physical causes are real. We believe the place to unpick this assumption is in biology and biomedicine itself, especially in the relation between biological processes and physics and chemistry. Ernst Schrödinger’s insight that biological processes run locally counter to the general direction of the second law of thermodynamics is now mainstream biophysics, as is his proposal that this is originally achieved by genes exercising information-based regulatory control of energetic processes. Information-based regulatory control mechanisms are a new and distinctive form of causation compared with conformity to the energy equations of physics and chemistry, most clearly evident in the fact that they can break down. This serves to argue against physicalism and is consistent with recent innovations in the philosophy of causation. The new concepts and principles of regulatory control apply in biology, but they also run through the psychological and social domains. This enables a more unified science, and one that has foundational differences between life and death, health and illness.
Psychology Regulates Activity in the Social World
Authors: Bolton Derek , Gillett Grant
Published: March 2019

Moving on from biology to psychology, we propose that the core function of the psychological is agency. This conception of the psychological in the new reworked biopsychosocial theory is consistent with current psychology and neuroscience, for example the so-called 4 Es model of cognition as embodied, embedded, enactive and extended. Agency has conditions in the social and political domains—signified by concepts of autonomy and recognition—the failure of which can jeopardise the perception and exercise of agency and hence psychological health. The third component of the biopsychosocial—the social—is defined within this framework as essentially to do with control and distribution of the resources necessary for biological and psychological life. The main theme of biopsychosocial interactions threads through the chapter, including theorising the notorious (for reductionism) ‘top-down’ causal pathways. This chapter aims to provide a framework to understand how factors involved in health and disease, particularly in the contexts of public health, and managing with long-term conditions, are increasingly seen to extend beyond the internal biological environment into the psychological, social, economic and political conditions of living.
Ultraviolet completion of a composite asymmetric dark matter model with a dark photon portal
Authors: Ibe Masahiro , Kamada Ayuki , Kobayashi Shin , Kuwahara Takumi , Nakano Wakutaka
Published: March 2019

Abstract

Composite asymmetric dark matter scenarios naturally explain why the dark matter mass density is comparable with the visible matter mass density. Such scenarios generically require some entropy transfer mechanism below the composite scale; otherwise, their late-time cosmology is incompatible with observations. A tiny kinetic mixing between a dark photon and the visible photon is a promising example of the low-energy portal. In this paper, we demonstrate that grand unifications in the dark and the visible sectors explain the origin of the tiny kinetic mixing. We particularly consider an ultraviolet completion of a simple composite asymmetric dark matter model, where asymmetric dark matter carries a B − L charge. In this setup, the longevity of asymmetric dark matter is explained by the B − L symmetry, while the dark matter asymmetry originates from the B−L asymmetry generated by thermal leptogenesis. In our minimal setup, the Standard Model sector and the dark sector are unified into SU(5)GUT × SU(4)DGUT gauge theories, respectively. This model generates required B − L portal operators while suppressing unwanted higher-dimensional operators that could wash out the generated B − L asymmetry.
Microbial electron uptake in microbial electrosynthesis: a mini-review
Authors: Karthikeyan Rengasamy , Singh Rajesh , Bose Arpita
Published: March 2019

Microbial electron uptake (EU) is the biological capacity of microbes to accept electrons from electroconductive solid materials. EU has been leveraged for sustainable bioproduction strategies via microbial electrosynthesis (MES). MES often involves the reduction of carbon dioxide to multi-carbon molecules, with electrons derived from electrodes in a bioelectrochemical system. EU can be indirect or direct. Indirect EU-based MES uses electron mediators to transfer electrons to microbes. Although an excellent initial strategy, indirect EU requires higher electrical energy. In contrast, the direct supply of cathodic electrons to microbes (direct EU) is more sustainable and energy efficient. Nonetheless, low product formation due to low electron transfer rates during direct EU remains a major challenge. Compared to indirect EU, direct EU is less well-studied perhaps due to the more recent discovery of this microbial capability. This mini-review focuses on the recent advances and challenges of direct EU in relation to MES.
Influence of R and S enantiomers of 1-octen-3-ol on gene expression of Penicillium chrysogenum
Authors: Yin Guohua , Zhang Yuliang , Fu Maojie , Hua Sui Sheng T , Huang Qixing , Pennerman Kayla K , Wu Guangxi , Jurick Wayne M , Lee Samantha , Bu Lijing , Zhao Hui , Bennett Joan W
Published: March 2019

Inhibition of spore germination offers an attractive and effective target for controlling fungal species involved in food spoilage. Mushroom alcohol (1-octen-3-ol) functions as a natural self-inhibitor of spore germination for many fungi and, therefore, provides a useful tool for probing the molecular events controlling the early stages of fungal growth. In Penicillium spp., the R and S enantiomers of 1-octen-3-ol delayed spore germination and sporulation in four species of Penicillium involved in soils of fruit and grains, but to different degrees. Because of its well-annotated genome, we used Penicillium chrysogenum to perform a comprehensive comparative transcriptomic analysis of cultures treated with the two enantiomers. Altogether, about 80% of the high-quality reads could be mapped to 11,396 genes in the reference genome. The top three active pathways were metabolic (978 transcripts), biosynthesis of secondary metabolites (420 transcripts), and microbial metabolism in diverse environments (318 transcripts). When compared to the control, treatment with (R)-(-)-1-octen-3-ol affected the transcription levels of 91 genes, while (S)-(+)-1-octen-3-ol affected only 41 genes. Most of the affected transcripts were annotated and predicted to be involved in transport, establishment of localization, and transmembrane transport. Alternative splicing and SNPs’ analyses indicated that, compared to the control, the R enantiomer had greater effects on the gene expression pattern of Penicillium chrysogenum than the S enantiomer. A qRT-PCR analysis of 28 randomly selected differentially expressed genes confirmed the transcriptome data. The transcriptomic data have been deposited in NCBI SRA under the accession number SRX1065226.
Identification of donors for low-nitrogen stress with maize lethal necrosis (MLN) tolerance for maize breeding in sub-Saharan Africa
Authors: Das Biswanath , Atlin Gary N. , Olsen Michael , Burgueño Juan , Tarekegne Amsal , Babu Raman , Ndou Eric N. , Mashingaidze Kingstone , Moremoholo Lieketso , Ligeyo Dickson , Matemba-Mutasa Rumbidzai , Zaman-Allah Mainassara , San Vicente Felix , Prasanna B. M. , Cairns Jill E.
Published: March 2019

After drought, a major challenge to smallholder farmers in sub-Saharan Africa is low-fertility soils with poor nitrogen (N)-supplying capacity. Many challenges in this region need to be overcome to create a viable fertilizer market. An intermediate solution is the development of maize varieties with an enhanced ability to take up or utilize N in severely depleted soils, and to more efficiently use the small amounts of N that farmers can supply to their crops. Over 400 elite inbred lines from seven maize breeding programs were screened to identify new sources of tolerance to low-N stress and maize lethal necrosis (MLN) for introgression into Africa-adapted elite germplasm. Lines with high levels of tolerance to both stresses were identified. Lines previously considered to be tolerant to low-N stress ranked in the bottom 10% under low-N confirming the need to replace these lines with new donors identified in this study. The lines that performed best under low-N yielded about 0. 5 Mg ha−1(20%) more in testcross combinations than some widely used commercial parent lines such as CML442 and CML395. This is the first large scale study to identify maize inbred lines with tolerance to low-N stress and MLN in eastern and southern Africa.
Chronic Lower Leg Pain in Athletes: Overview of Presentation and Management
Authors: Mohile Neil , Perez Jose , Rizzo Michael , Emerson Christopher P. , Foremny Greg , Allegra Paul , Greditzer Harry G. , Jose Jean
Published: March 2019

Background

Athletes with chronic lower leg pain present a diagnostic challenge for clinicians due to the differential diagnoses that must be considered.

Purpose/Questions

We aimed to review the literature for studies on the diagnosis and management of chronic lower leg pain in athletes.

Methods

A literature review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). The PubMed, Scopus, and Cochrane library databases were searched, and articles that examined chronic lower leg pain in athletes were considered for review. Two independent reviewers conducted the search utilizing pertinent Boolean operations.

Results

Following two independent database searches, 275 articles were considered for initial review. After the inclusion and exclusion criteria were applied, 88 were included in the final review. These studies show that the most common causes of lower leg pain in athletes include medial tibial stress syndrome, chronic exertional compartment syndrome, tibial stress fractures, nerve entrapments, lower leg tendinopathies, and popliteal artery entrapment syndrome. Less frequently encountered causes include saphenous nerve entrapment and tendinopathy of the popliteus. Conservative management is the mainstay of care for the majority of cases of chronic lower leg pain; however, surgical intervention may be necessary.

Conclusions

Multiple conditions may result in lower leg pain in athletes. A focused clinical history and physical examination supplemented with appropriate imaging studies can guide clinicians in diagnosis and management. We provide a table to aid in the differential diagnosis of chronic leg pain in the athlete.