bluuebunny/crossref_metadata_2025 huggingface dataset:
The toxic potential of a fourth‐generation E‐cigarette on human lung cell lines and tissue explants
Authors: Rankin Gregory D. , Wingfors Håkan , Uski Oskari , Hedman Linnéa , Ekstrand‐Hammarström Barbro , Bosson Jenny , Lundbäck Magnus
Published: April 2019

The use of electronic cigarettes (E‐cigs) is rapidly increasing. The latest generation of E‐cigs is highly customizable, allowing for high heating coil temperatures. The aim of this study was to assess the toxic potential of a fourth‐generation E‐cig. Aerosols generated from E‐liquid with (24 mg/mL) and without nicotine, using a fourth‐generation E‐cig, were chemically analysed and compared with cigarette smoke (K3R4F). Human lung epithelial cell lines and distal lung tissue explants were exposed to E‐cig vapour extract (EVE) and cigarette smoke extract for 24 hours and assessed for viability, inflammation, oxidative stress and genotoxicity. E‐cig aerosols contained measurable levels of volatile organic compounds, aldehydes and polycyclic aromatic hydrocarbons, in general, to a much lesser extent than cigarette smoke. Higher levels of certain carbonyls, e.g. formaldehyde, were detected in the E‐cig aerosols. EVEs decreased cell viability of BEAS‐2B cells, whereas little effect was seen in A549 cells and distal lung tissue. The nicotine‐containing EVE caused a greater decrease in cell viability and significant increase in DNA damage than the nicotine‐free EVE. Increased cytotoxicity, reactive oxygen species production and genotoxicity were seen with cells and tissue exposed to cigarette smoke extract compared with EVEs. Although E‐cig aerosols were less toxic than cigarette smoke, it was not benign. Moreover, the EVE containing nicotine was more toxic than the nicotine‐free EVE. More research is needed on the short‐ and long‐term health effects of vaping and the usage of newly emerging E‐cig devices to evaluate better the potential negative effects of E‐cigs on human health.
Is normalized hindlimb length measurement in assessment of thyroid disruption in the amphibian metamorphosis assay relevant?
Authors: Pawlowski Sascha , Dammann Martina , Weltje Lennart , Champ Samantha , Mathis Michael , Fort Douglas J.
Published: April 2019

The amphibian metamorphosis assay represents an OECD Level 3 and EDSP Tier 1 ecotoxicity test assessing thyroid activity of chemicals in African clawed frog (Xenopus laevis). To evaluate the effectiveness of snout‐vent length (SVL) normalization of hindlimb length (HLL), correlation between the HLL and SVL or body weight was evaluated in the control groups of 10 individual studies from three laboratories. Two studies required separate analysis of the Nieuwkoop‐Faber (NF) stage ≤60 and >60 animals creating a total of 12 data sets. On study day 7, significant positive correlation between HLL and SVL or body weight was observed in eight and seven of the 10 data sets, respectively (r = 0.608‐0.843 and 0.583‐0.876). On study day 21, significant positive correlation between HLL and SVL or body weight was found in three and four of the 12 data sets, respectively (r = 0.452, 0.480 and 0.553 and r = 0.621, 0.546, 0.564 and 0.378). Significant positive correlation between HLL and SVL was found in three of five studies, including ≤NF stage 60 data (r = 0.564, 0.546 and 0.621). In one of eight studies, including >NF stage 60 data, the positive correlation between HLL and body weight was determined (r = 0.378). Negative or no correlation between HLL and SVL or body weight was found in the other late stage data sets. Therefore, use of SVL‐normalized HLL to assess thyroid‐mediated effects in X. laevis tadpoles is not warranted. HL stage relative to body stage should be considered.
Fibrin hydrogel as a scaffold for differentiation of induced pluripotent stem cells into oligodendrocytes
Authors: Nazari Bahareh , Kazemi Mansure , Kamyab Ahmadreza , Nazari Banafsheh , Ebrahimi‐Barough Somayeh , Hadjighassem Mahmoudreza , Norouzi‐Javidan Abbas , Ai Arman , Ahmadi Akbar , Ai Jafar
Published: April 2019

The importance of tissue engineering has been established as a promising approach in treating neurodegenerative diseases. The purpose of the current study is to determine the effect of fibrin hydrogel on the differentiation of iPSC into oligodendrocyte. For this purpose, iPSCs transduced by miR‐338 expressing lentiviruses. They were treated with basic fibroblast growth factor (bFGF), epidermal growth factor (EGF), and platelet‐derived growth factor (PDGF)‐AA. The process was traced by a 6‐day treatment in a mitogen‐free medium. At the end of the process, multipolar preoligodendrocytes appeared. In comparison to tissue culture plate (TCP), MTT assay demonstrated a significant increase in the viability of cells cultured in fibrin hydrogel. SEM analysis showed cells with elongated morphology and intertwined intercellular interactions. An immunofluorescent assay confirmed the expression of oligodendrocyte markers Olig2 and O4. In comparison to TCP, real‐time PCR data indicated a significant increase in the expression of some markers such as Olig2, MBP, Sox10, and PDGFRα on cells encapsulated in fibrin hydrogel. Overall, the results suggest that fibrin hydrogel improves viability of cells and promotes the differentiation of iPSCs into preoligodendrocytes. Hence, it can be used as an appropriate option in the tissue engineering in order to treat neurodegenerative diseases. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 108B:192–200, 2020.
Chalcopyrite bioleaching in the presence of high chloride concentrations
Authors: Martins Flávio L , Patto Guilherme B , Leão Versiane A
Published: April 2019

Background

Dissolution of chalcopyrite is one of the most important challenges in hydrometallurgy because it is very difficult to leach due to the passivation of its surface, whose nature is still controversial. The addition of chloride ions can catalyse copper dissolution, but when it comes to bioleaching, chloride usually cannot be applied because of its toxicity to most bioleaching bacteria.

Results

The current work investigated, for the first time, chalcopyrite bioleaching with Sulfolobus acidocaldarius at high concentrations of chloride [up to 1.0 mol L−1 sodium chloride (NaCl)] and 67.5 °C. Copper dissolution attained 100% within 14 days in the presence of microorganisms, while only 55% was observed in the abiotic test; both tests were carried out with 1.0 mol L−1 NaCl. Raman spectroscopy of the leached chalcopyrite with S. acidocaldarius and 1.0 mol L−1 NaCl revealed the presence of elemental sulphur as a reaction product on the fifth day of the experiment; jarosite was also detected after 14 days in the same test.

Conclusion

Because of the low ability of the archaea to oxidize ferrous ion, the redox potential of the biotic test, having 1.0 mol L−1 of chloride, remained most of the time in the range 350–420 mV, in which the leaching rate of chalcopyrite was the highest. © 2019 Society of Chemical Industry
Retest and treat: a review of national HIV retesting guidelines to inform elimination of mother‐to‐child HIV transmission (EMTCT) efforts
Authors: Drake Alison L , Thomson Kerry A , Quinn Caitlin , Newman Owiredu Morkor , Nuwagira Innocent B , Chitembo Lastone , Essajee Shaffiq , Baggaley Rachel , Johnson Cheryl C
Published: April 2019

Introduction

High maternal HIV incidence contributes substantially to mother‐to‐child HIV transmission (MTCT) in some settings. Since 2006, HIV retesting during the third trimester and breastfeeding has been recommended by the World Health Organization in higher prevalence (≥5%) settings to reduce MTCT. However, many countries lack clarity on when and how often to retest pregnant and postpartum women to optimize resources and service delivery. We reviewed and characterized national guidelines on maternal retesting based on timing and frequency.

Methods

We identified 52 countries to represent variations in HIV prevalence, geography, and MTCT priority and searched available national MTCT, HIV testing and HIV treatment policies published between 2007 and 2017 for recommendations on retesting during pregnancy, labour/delivery and postpartum. Recommended retesting frequency and timing was extracted. Country HIV prevalence was classified as: very low (<1%), low (1% to 5%), intermediate (>5 to <15%) and high (≥15%). Women with unknown HIV status at delivery/postpartum were included in retesting guidelines.

Results and discussion

Overall, policies from 49 countries were identified; 51% from 2015 or later and most (n = 25) were from Africa. Four countries were high HIV prevalence, seven intermediate, sixteen low and twenty‐two very low. Most (n = 31) had guidance on universal voluntary opt‐out HIV testing at the first antenatal care (ANC) visit. Beyond the first ANC visit, the majority (78%, n = 38) had guidance on retesting; 22 recommended retesting all women with unknown/negative status, five only if unknown HIV status, three in pregnancy based on risk and eight combining these approaches. Retesting was universally recommended during pregnancy, labour/delivery, and postpartum for all high prevalence settings and four of seven intermediate prevalence settings. Five UNAIDS priority countries for EMTCT with low/very low HIV prevalence, but high/intermediate MTCT, had no guidance on retesting.

Conclusions

Retesting guidelines for pregnant and postpartum women were ubiquitous in high prevalence countries and defined in some intermediate prevalence countries, but absent in some low HIV prevalence countries with high MTCT. Countries may require additional guidance on how to optimize maternal HIV testing and whether to prioritize retesting efforts or discontinue universal retesting based on HIV incidence. Research is needed to assess country‐level guideline implementation and impact.
Orphans and Pro‐social Behaviour: Evidence from Uganda
Authors: McCannon Bryan C. , Rodriguez Zachary
Published: April 2019

Disease and violence escalates the prevalence of orphanhood. We investigate whether individuals who were orphaned as a child suffer long‐term consequences on their pro‐sociality. We conduct a lab‐in‐the‐field experiment in rural Uganda where, among other contributing factors, the HIV/AIDS pandemic hit hardest. Subjects made decisions to contribute to a public good. Results indicate that adults who were orphaned as a child contribute less. We provide evidence that an important channel through which the mechanism operates is through social norms. Subjects orphaned tend to have lower expectations regarding typical behaviour of others. A strong interaction effect is identified where those with the lowest expectations who were also orphaned contribute the least to the public good. Thus, we document orphanhood's long‐term consequences to a community. © 2019 John Wiley & Sons, Ltd.
Step‐function luminopsins for bimodal prolonged neuromodulation
Authors: Berglund Ken , Fernandez Alejandra M. , Gutekunst Claire‐Anne N. , Hochgeschwender Ute , Gross Robert E.
Published: April 2019

Although molecular tools for controlling neuronal activity by light have vastly expanded, there are still unmet needs which require development and refinement. For example, light delivery into the brain is still a major practical challenge that hinders potential translation of optogenetics in human patients. In addition, it would be advantageous to manipulate neuronal activity acutely and precisely as well as chronically and non‐invasively, using the same genetic construct in animal models. We have previously addressed these challenges by employing bioluminescence and have created a new line of opto‐chemogenetic probes termed luminopsins by fusing light‐sensing opsins with light‐emitting luciferases. In this report, we incorporated Chlamydomonas channelrhodopsin 2 with step‐function mutations as the opsin moiety in the new luminopsin fusion protein termed step‐function luminopsin (SFLMO). Bioluminescence‐induced photocurrent lasted longer than the bioluminescence signal due to very slow deactivation of the mutated channel. In addition, bioluminescence was able to activate most of the channels on the cell surface due to the extremely high light sensitivity of the channel. This efficient channel activation was partly mediated by radiationless bioluminescence resonance energy transfer due to the proximity of luciferase and opsin. To test the utility of SFLMOs in vivo, we transduced the substantia nigra unilaterally via a viral vector in male rats. Injection of the luciferase substrate as well as conventional photostimulation via fiber optics elicited circling behaviors. Thus, SFLMOs expand the current approaches for manipulation of neuronal activity in the brain and add more versatility and practicality to optogenetics in freely behaving animals.
Optimization and Characterization of Biosurfactant Rhamnolipid Production by Pseudomonas aeruginosa Isolated from an Artificially Contaminated Soil
Authors: Câmara Jéssica Maria D.A. , Sousa Magna Angélica S.B. , Barros Neto Eduardo L.
Published: April 2019

Biosurfactants are surfactants biologically produced by microorganisms, presenting several advantages when compared to synthetic surfactants. Pseudomonas aeruginosa is known for producing rhamnolipids, considered one of the most interesting types of biosurfactants due to their high yields, when compared to other types. In this work, the production of rhamnolipid from P. aeruginosa was optimized. At first, the Plackett–Burman design was used to select most significant variables affecting the biosurfactant production yield among nine variables—carbon–nitrogen ratio, carbon concentration, nitrogen source, pH, cultivation time, potassium and magnesium concentrations, agitation, and temperature. Then, using main variables, a central point experimental design aiming to optimize rhamnolipid production was performed. The maximum biosurfactant concentration obtained was 0.877 mg L−1. The rhamnolipid also displayed a great emulsification rate, reaching approximately 67%, and the ability to reduce water surface tension from 72.02 to 35.26 mN m−1 at a critical micelle concentration (CMC) of 127 mg L−1, in addition to presenting a good stability when exposed to wide pH and salinity ranges. The results suggest that rhamnolipids are promising substitutes for synthetic surfactants, especially due to lower impacts on the environment.
Liquid Gallium Nanospheres Emitting White Light
Authors: Xiang Jin , Chen Jingdong , Jiang Shuai , Panmai Mingcheng , Li Peilian , Xu Yi , Dai Qiaofeng , Tie Shaolong , Lan Sheng
Published: April 2019

Gallium (Ga) is not only a metal possessing surface plasmon resonance in the ultraviolet region but also a phase‐change material with very low melting point. Spherical Ga nanoparticles composed of liquid Ga cores and solid Ga2O3 shells, which exhibit surface plasmonic resonances spanning the ultraviolet to near‐infrared spectral region, are fabricated by using femtosecond laser ablation. Under the excitation of femtosecond laser light, only second harmonic generation is observed in the Ga nanospheres placed on a glass substrate. In sharp contrast, white light emission can be generated in such Ga nanospheres when they are placed on a thin silver film. It is revealed numerically and confirmed experimentally that a Fano resonance originating from the interference between the mirror‐image‐induced magnetic dipole mode and the gap plasmon mode is formed in the backward scattering spectra of the Ga nanospheres. Efficient white light emission can be achieved by resonantly exciting either the magnetic dipole resonance or the Fano resonance. Based on spectral analysis, the white light emission is identified as the hot‐electron intraband luminescence. The fabricated core–shell Ga nanospheres provide an ideal platform on which the optical properties and practical applications of liquid Ga nanoparticles can be systematically investigated.
Predicting impacts of climate change on the potential distribution of two interacting species in the forests of western Iran
Authors: Malekian Mansoureh , Sadeghi Maedeh
Published: April 2019

Predicting the distribution of suitable habitats for species under climate change is essential for conservation planning. In the past three decades, the number of Persian squirrels (Sciurus anomalus) and the area covered by the Persian oak (Quercus brantii) have decreased due to various factors such as habitat degradation. Habitat suitability of the above interacting species was assessed under the current conditions and future (2050) climate change scenarios in western Iran, using a maximum entropy model (MaxEnt). The model performed well with an average area under the curve of above 0.9 for the two species. Precipitation in winter was the factor that contributed most to habitat suitability of both species. The MaxEnt projection for the year 2050 revealed a reduction in the area of suitable habitats for both species. Based on the outputs from the Hadley Centre for Climate Prediction and Research Coupled Model (HadCM) scenarios, the fundamental niche (the range of environmental conditions in which the species can survive) of the Persian squirrel will reduce by between 0.12 and 1.1%. However, under the Centre National de Recherches Météorologiques Coupled Model scenarios, small gains in potential habitats may be observed. The area of suitable habitats for the oak was reduced under all scenarios except HadCM (representative concentration pathway 2.6). The results showed that the loss of suitable habitats for both species was more evident in the northern part of the range where the best habitats currently exist. In contrast, small gains in suitable habitats may be observed in the southern and eastern part of the range.
Brief intervention reveals rapport between physician, patient
Authors: Canady Valerie A.
Published: April 2019

Among the presentations at this year's NATCON (National Council for Behavioral Health conference). was a session on a brief 30‐minute encounter to represent what a patient's initial assessment would look like in an integrated care setting if a clinician had only that amount of time.
Stochastic semi‐discretization for linear stochastic delay differential equations
Authors: Sykora Henrik T , Bachrathy Daniel , Stepan Gabor
Published: April 2019

An efficient numerical method is presented to analyze the moment stability and stationary behavior of linear stochastic delay differential equations. The method is based on a special kind of discretization technique with respect to the past effects. The resulting approximate system is a high dimensional linear discrete stochastic mapping. The convergence properties of the method is demonstrated with the help of the stochastic Hayes equation and the stochastic delayed oscillator.
Qualitative thematic analysis based on descriptive phenomenology
Authors: Sundler Annelie J. , Lindberg Elisabeth , Nilsson Christina , Palmér Lina
Published: April 2019

Aim

The aim of this paper was to discuss how to understand and undertake thematic analysis based on descriptive phenomenology. Methodological principles to guide the process of analysis are offered grounded on phenomenological philosophy. This is further discussed in relation to how scientific rigour and validity can be achieved.

Design

This is a discursive article on thematic analysis based on descriptive phenomenology.

Results

This paper takes thematic analysis based on a descriptive phenomenological tradition forward and provides a useful description on how to undertake the analysis. Ontological and epistemological foundations of descriptive phenomenology are outlined. Methodological principles are explained to guide the process of analysis, as well as help to understand validity and rigour. Researchers and students in nursing and midwifery conducting qualitative research need comprehensible and valid methods to analyse the meaning of lived experiences and organize data in meaningful ways.
Effect of multiscale structure on the gas barrier properties of poly(lactic acid)/Ag nanocomposite films
Authors: Fan Chunli , Chi Hai , Zhang Cheng , Cui Rui , Lu Wangwei , Yuan Minglong , Qin Yuyue
Published: April 2019

Poly(lactic acid) (PLA) is the most suitable for biodegradable packaging film because of its excellent integrated property, but the poor gas barrier property is its weakness. In this study, a nanocomposite film based on PLA incorporated with 0‐, 1‐, 3‐, 5‐, 10‐, or 15‐wt% nano‐Ag was developed. Effect of multiscale structure on the barrier properties of PLA/nano‐Ag films was studied. The PLA nanocomposite film with 5‐wt% nano‐Ag had the lowest water vapor permeability (WVP) value. Oxygen transmission rate (OTR) value for PLA nanocomposites with 3‐wt% nano‐Ag was found to be the lowest among all the samples. Multiscale structure was demonstrated by the scanning electron microscopy, Fourier transform‐infrared spectroscopy, X‐ray diffraction measurement, and differential scanning calorimetry results. The crystallinity of the PLA phase increased with the content of nano‐Ag in the PLA composites. The evolution of the PLA phase crystallinity could improve the barrier properties of PLA/nano‐Ag composite films for food packaging applications. From the view of multiscale structure, it is better to achieve a balance among short‐range conformation in the amorphous region, long‐range‐ordered structure, and ordered aggregated structure to improve the barrier properties of PLA/nano‐Ag composite films.
Injection molding of short coir fiber polypropylene biocomposites: Prediction of the mold filling phase
Authors: Semlali Aouragh Hassani Fatima‐Zahra , Ouarhim Wafa , Zari Nadia , Bensalah Mohammed Ouadi , Rodrigue Denis , Bouhfid Rachid , Qaiss Abou el kacem
Published: April 2019

The mold‐filling phase in injection molding is the most important one because the material flow behavior controls the final part structure. In this work, the effect of melt rheology on the flow front progression of coir fiber (2.5, 5, 10, and 15 wt%) filled polypropylene is investigated. The flow behavior is predicted using the incompressible Navier–Stokes equations to determine the flow front shape and position and the model proposed is in good agreement with the experimental results for the range of conditions studied. Finally, to provide a better understanding of the effect of different processing conditions (pressure, melt, and mold temperature) on the flow front evolution, several simulations were performed using Autodesk Moldflow Insight. POLYM. COMPOS., 40:4042–4055, 2019. © 2019 Society of Plastics Engineers
Downregulation of CENPF Remodels Prostate Cancer Cells and Alters Cellular Metabolism
Authors: Shahid Muhammad , Kim Minhyung , Lee Min Young , Yeon Austin , You Sungyong , Kim Hyung L. , Kim Jayoung
Published: April 2019

Metabolic alterations in prostate cancer (PC) are associated with progression and aggressiveness. However, the underlying mechanisms behind PC metabolic functions are unknown. The authors’ group recently reported on the important role of centromere protein F (CENPF), a protein associated with the centromere–kinetochore complex and chromosomal segregation during mitosis, in PC MRI visibility. This study focuses on discerning the role of CENPF in metabolic perturbation in human PC3 cells. A series of bioinformatics analyses shows that CENPF is one gene that is strongly associated with aggressive PC and that its expression is positively correlated with metastasis. By identifying and reconstructing the CENPF network, additional associations with lipid regulation are found. Further untargeted metabolomics analysis using gas chromatography‐time‐of‐flight‐mass spectrometry reveals that silencing of CENPF alters the global metabolic profiles of PC cells and inhibits cell proliferation, which suggests that CENPF may be a critical regulator of PC metabolism. These findings provide useful scientific insights that can be applied in future studies investigating potential targets for PC treatment.
Determination of the structural ensemble of the molten globule state of a protein by computer simulations
Authors: Shimizu Masahiro , Kajikawa Yukihito , Kuwajima Kunihiro , Dobson Christopher M. , Okamoto Yuko
Published: April 2019

We have used computer simulations to investigate the structural nature of the molten globule (MG) state of canine milk lysozyme. To sample the conformational space efficiently, we performed replica‐exchange umbrella sampling simulations with the radius of gyration as a reaction coordinate. We applied the Weighted Histogram Analysis Method to the trajectory of the simulations to obtain the potential of mean force, from which we identified representative structures corresponding to local minima in the free energy surface. The representative structures obtained in this way are in accord with the characteristics of the MG state reported previously by experimental studies. We conjecture that the MG state comprises a series of partially structured states undergoing relatively fast conformational interchange.
Sequence and structure‐based characterization of ubiquitination sites in human and yeast proteins using Chou's sample formulation
Authors: Kumar Vanitha Shyamili , Vellaichamy Adaikkalam
Published: April 2019

Ubiquitination is an important post‐translational event responsible for half‐life and turnover of proteins inside the cell. Proteins are ubiquitinated by forming an iso‐peptide bond between their lysine residue and C‐terminal glycine residue of ubiquitin leading to rapid degradation of proteins by 26S proteosome complex. Deregulation of ubiquitination is manifested by aberrant expression of E3‐ligase activity or mutation in the surroundings of ubiquitination sites. Many new experimentally validated ubiquitinated lysines have been recently identified that motivated the study of the environments surrounding the ubiquitinated lysines. With the help of known ubiquitinated proteins, here we present a comprehensive study of sequence and spatial environment of ubiquitination sites of human and yeast proteins. To identify position‐specific features, this work distinguishes the spatial environments as proximity and distal regions. Certain amino acids specific to these regions, well differentiate the ubiquitination sites from non‐ubiquitination sites are revealed. Additionally, amino acid signatures that contribute for protein disordered regions and solvent accessibility of amino acids are found to be contributing factors in ubiquitination sites. These results suggest that the ubiquitination site environment of the substrate determines the recognition and unfolding of substrate to facilitate the entry into 26S proteosomal complex. We believe that these findings will help in better prediction of ubiquitination sites using the sequence and spatial information.
Molecular modeling study on the differential microtubule‐stabilizing effect in singly‐ and doubly‐bonded complexes with peloruside A and paclitaxel
Authors: Zúñiga Matías A. , Alderete Joel B. , Jaña Gonzalo A. , Navarrete Karen R. , Jiménez Verónica A.
Published: April 2019

Microtubules (MT) are dynamic cytoskeletal components that play a crucial role in cell division. Disrupting MT dynamics by MT stabilizers is a widely employed strategy to control cell proliferation in cancer therapy. Most MT stabilizers bind to the taxol (TX) site located at the luminal interface between protofilaments, except laulimalide and peloruside A (PLA), which bind to an interfacial pocket on outer MT surface. Cryo‐electron microscopy MTs reconstructions have shown differential structural effects on the MT lattice in singly‐ and doubly‐bonded complexes with PLA, TX, and PLA/TX, as PLA is able to revert the lattice heterogeneity induced by TX association leading to more regular MT assemblies. In this work, fully‐atomistic molecular dynamics simulations were employed to examine the single and double association of MT stabilizers to reduced MT models in the search for structural and energetic evidence that could be related to the differential regularization and stabilization effects exerted by PLA and TX on the MT lattice. Our results revealed that the double association of PLA/TX (a) strengthens the lateral contact between tubulin dimers compared to singly‐bonded complexes, (b) favors a more parallel arrangement between tubulin dimers, and (c) induces a larger restriction in the interdimeric conformational motion increasing the probability of finding structures consistent with 13‐protofilaments arrangements. These results and are valuable to increase understanding about the molecular mechanism of action of MT stabilizers, and could account for an overstabilization of MTs in doubly‐bonded complexes compared to singly‐bonded systems.
Finite‐time boundedness of large‐scale systems with actuator faults and gain fluctuations
Authors: Tharanidharan V. , Sakthivel R. , Kaviarasan B. , Alzahrani Faris , Marshal Anthoni S.
Published: April 2019

This paper addresses the issue of finite‐time boundedness of large‐scale interconnected systems with the use of a distributed nonfragile fault‐tolerant controller. The objective of this paper is to design a state‐feedback controller consisting of a time‐varying delay such that the resulting closed‐loop system is finite‐time bounded under a prescribed extended passivity performance level even in the presence of all admissible uncertainties and possible actuator faults. More precisely, based on the Lyapunov‐Krasovskii stability theory, a new set of sufficient conditions is obtained in the framework of linear matrix inequality constraints that ensures finite‐time boundedness and satisfies the prescribed extended passivity performance index of the considered system. Finally, two numerical examples, including the interconnected inverted pendulum, are given to show the effectiveness of the proposed controller design technique.
Round‐robin test of medium‐energy ion scattering for quantitative depth profiling of ultrathin HfO2/SiO2/Si films
Authors: Min Won Ja , Marmitt Gabriel ,   RRT Participants, Grande Pedro L. , Moon DaeWon
Published: April 2019

Medium‐energy ion scattering (MEIS) has been used for quantitative depth profiling with single atomic layer resolution to determine the composition, thickness, and interface structure of ultrathin films and nanoparticles. To assure the consistency of the MEIS analysis, an international round‐robin test (RRT) with nominally 1‐, 3‐, 5‐, and 7‐nm thick HfO2 films was conducted among 12 institutions. The measurements were performed at each participating laboratory under their own conditions, and the collected data were analyzed. For the data analysis, the Moliere potential, the stopping and range of ions in matter (SRIM) 95 and new fitted electronic stopping power and the Chu straggling were used. For analyzing the MEIS data from the magnetic sector and electrostatic analyzers, the neutralization corrections of Marion and Young for 100‐keV H+ and He+ ions and of Armstrong for 400‐ to 500‐keV He+ ions were used. The standard deviations were 5.3% for the composition, 15.3% for the thickness, and 13.3% for the Hf content, and they were improved to 7.3%, 4.5%, and 7.0% by using refitted electronic stopping powers based on the experimental data. Hence, this study suggests that correct electronic stopping powers are critical for quantitative MEIS analysis.
Synthesis of A Novel Cross‐linker with High Reactivity for Enhancing Compressive Strength of High‐performance Organic Fibers
Authors: Dai Yu , Feng Jiabao , Meng Chenbo , Luo Longbo , Liu Xiangyang
Published: April 2019

Low axial compressive strength of high‐performance organic fibers is one of the most prominent problems for their application in advanced technologies. In this paper, N, N’‐diphenyl‐1,4‐phenylacetyleneamide (DPAA) as a novel external cross‐linker was synthesized. It was confirmed that DPAA could react itself and quickly form cross‐linking network above 210 °C with pore width of 1–30 nm. Then DPAA was introduced into some typical high‐performance organic fibers through post‐swelling process, followed by annealing at 250 °C. It was found that DPAA would in‐situ form cross‐linking network inside the fiber, which was regarded as semi‐interpenetration structure. Compressive strength of Kevlar‐49 fiber modified through this method increased by nearly 70% and corresponding tensile strength didn't deteriorate. When PBO, heterocyclic aramid and polyimide fibers were modified by the same procedure, their compressive strength showed 25, 36 and 72% enhancement respectively. Therefore, DPAA is an effective modifier to enhance compressive strength of high‐performance organic fibers and shows great universality.
The Binary Effect on Methicillin‐Resistant Staphylococcus aureus of Polymeric Nanovesicles Appended by Proline‐Rich Amino Acid Sequences and Inorganic Nanoparticles
Authors: Bassous Nicole J. , Webster Thomas J.
Published: April 2019

Prevalent research underscores efforts to engineer highly sophisticated nanovesicles that are functionalized to combat antibiotic‐resistant bacterial infections, especially those caused by methicillin‐resistant Staphylococcus aureus (MRSA), and that aid with wound healing or immunomodulation. This is especially relevant for patients who are susceptible to Staphylococcus aureus infections postoperatively. Here, antibacterial formulations are incorporated into polymeric, biocompatible vesicles called polymersomes (PsNPs) that self‐assemble via hydrophobic interactions of admixed aqueous and organic substances. Nano‐PsNPs are synthesized using a high molecular weight amphiphilic block copolymer, and are conjugated to include antimicrobial peptides (AMPs) along the peripheral hydrophilic region and silver nanoparticles (AgNPs) inside their hydrophobic corona. In vitro testing on bacterial and human cell lines indicates that finely tuned treatment concentrations of AMP and AgNPs in PsNPs synergistically inhibits the growth of MRSA without posing significant side effects, as compared with other potent treatment strategies. A ratio of silver‐to‐AMP of about 1:5.8 corresponding to ≈11.6 µg mL−1 of silver nanoparticles and 14.3 × 10−6 m of the peptide, yields complete MRSA inhibition over a 23 h time frame. This bacteriostatic activity, coupled with nominal cytotoxicity toward native human dermal fibroblast cells, extends the potential for AMP/AgNP polymersome therapies to replace antibiotics in the clinical setting.
Tape‐Imprinted Hierarchical Lotus Seedpod‐Like Arrays for Extraordinary Surface‐Enhanced Raman Spectroscopy
Authors: Wang Yandong , Zhang Mengyuan , Feng Lei , Dong Bin , Xu Ting , Li Dong , Jiang Lin , Chi Lifeng
Published: April 2019

A novel two‐side‐activatable high‐performance surface‐enhanced Raman spectroscopy (SERS) substrate is developed based on the tape‐imprinting method. It features 3D full‐space‐distributed hot spots originating from the hierarchical lotus seedpod‐like silver arrays, which offer ultrasensitive, uniform, reproducible, and reliable quantitative measurements with an inherent internal standard. This excellent SERS substrate also holds great promise in practical in situ molecule detection on curved surfaces, such as pesticides on fruit, which is not yet possible with the traditional rigid or flexible material‐based SERS counterparts.
2D Free‐Standing Nitrogen‐Doped Ni‐Ni3S2@Carbon Nanoplates Derived from Metal–Organic Frameworks for Enhanced Oxygen Evolution Reaction
Authors: Lin Yifan , Chen Gen , Wan Hao , Chen Fashen , Liu Xiaohe , Ma Renzhi
Published: April 2019

2D metal–organic frameworks (2D MOFs) are promising templates for the fabrication of carbon supported 2D metal/metal sulfide nanocomposites. Herein, controllable synthesis of a newly developed 2D Ni‐based MOF nanoplates in well‐defined rectangle morphology is first realized via a pyridine‐assisted bottom‐up solvothermal treatment of NiSO4 and 4,4′‐bipyridine. The thickness of the MOF nanoplates can be controlled to below 20 nm, while the lateral size can be tuned in a wide range with different amounts of pyridine. Subsequent pyrolysis treatment converts the MOF nanoplates into 2D free‐standing nitrogen‐doped Ni‐Ni3S2@carbon nanoplates. The obtained Ni‐Ni3S2 nanoparticles encapsulated in the N‐doped carbon matrix exhibits high electrocatalytic activity in oxygen evolution reaction. A low overpotential of 284.7 mV at a current density of 10 mA cm−2 is achieved in alkaline solution, which is among the best reported performance of substrate‐free nickel sulfides based nanomaterials.
Efficient Mixed‐Cation Mixed‐Halide Perovskite Solar Cells by All‐Vacuum Sequential Deposition Using Metal Oxide Electron Transport Layer
Authors: Kam Matthew , Zhu Yiyi , Zhang Daquan , Gu Leilei , Chen Jiaqi , Fan Zhiyong
Published: April 2019

The incorporation of various cations and halides to form mixed perovskites has enabled perovskite solar cells (PSCs) to exceed 20% power conversion efficiencies (PCEs). However, they are primarily prepared by solution methods, which limit film uniformity and scalability. Although co‐evaporation is used to prepare all‐vacuum‐deposited PSCs with a decent performance, it involves multiple sources and quartz crystal monitors (QCMs) to simultaneously control deposition rates and film thicknesses, which increase production cost and fabrication complexity and interfere QCMs’ reading precision. Herein, a simple and cost‐effective sequential vapor deposition involving only one QCM and two sources is demonstrated as an advantageous and reliable method to fabricate high‐quality and uniform mixed‐cation mixed‐halide perovskite films with microscale grain sizes and extraordinary morphology for the PSC application. In addition, for the first time, radio frequency (RF)‐sputtered SnO2 is implemented into all‐vacuum‐deposited PSCs as an electron transport layer (ETL). Together with evaporated copper phthalocyanine (CuPc) as a thermally and chemically stable low‐cost hole transport layer (HTL), alternative to the commonly used 2,2′,7,7′‐tetrakis(N,N‐di‐p‐methoxyphenylamino)‐9,9′‐spirobifluorene (Spiro‐OMeTAD), which is costly, highly hygroscopic, and deliquescent, a respectable PCE of 15.14% is achieved with a promising device stability and negligible hysteresis.
Flow Interaction in Continuous Casting Tundish Due to Bubble Curtain Operation
Authors: Holzinger Gerhard , Thumfart Maria
Published: April 2019

Tundish argon bubbling has been studied in literature regarding homogenization and non‐metallic inclusion removal. Argon bubbling not only alters the flow within the tundish, which might aid the natural flotation of inclusions, argon bubbles also can directly capture inclusions, when bubbles and inclusions collide. The ascending bubbles from the line sparger induce a recirculating flow within the tundish. This recirculating flow interacts with the incoming liquid jet, emanating from the ladle shroud. For a sufficiently strong recirculating flow, the incoming liquid jet is deflected in a similar manner as a jet in cross‐flow. For this paper, computational fluid dynamics (CFD) simulations have been carried out with OpenFOAM to reproduce experiments, studying the jet deflection in a 1:3 water model due to gas bubbling. In the course of the CFD simulations, several modeling approaches are tested. A significantly large jet deflection might adversely affect the internal flow patterns of the tundish, as the liquid jet might hit a present turbulence inhibitor off‐center or miss it entirely. Tundish jet deflection constitutes an adverse effect of gas bubbling in a tundish leading to an off‐design, internal flow, which has not been studied so far, to the best of the authors’ knowledge.
Calibrated adversarial algorithms for generative modelling
Authors: Tan Zhiqiang , Song Yunfu , Ou Zhijian
Published: April 2019

Generative adversarial networks are useful for unsupervised learning but may be difficult to train. We study a class of adversarial algorithms based on f‐divergence minimization and provide an extension by allowing two objective functions instead of one to be chosen (hence calibrated) for updating the discriminator and the generator, respectively. The extension is derived and justified from theoretical analysis, which identifies specific objective functions for achieving stable gradients in the corresponding updates. Our experiments on synthetic data and MNIST and CIFAR‐10 datasets demonstrate that the proposed method consistently achieves competitive or superior results when compared with various existing methods.
Pregnancies alters spine number in cortical and subcortical limbic brain regions of old rats
Authors: Flores‐Vivaldo Yaredit Margarita , Camacho‐Abrego Israel , Picazo Ofir , Flores Gonzalo
Published: April 2019

Pregnancy is a complex process, involving a number of hormones and trophic factors, many of which are formed in the placenta. Several of these trophic factors have an effect at the neuronal level, such as BDNF. Consequently, recent reports have shown that exposure to these hormones (estrogen and progesterone) and trophic factors such as BDNF exert a neuroprotective effect. Here, we study the effect of the number of pregnancies on dendritic morphology of aged female rats (18 months of age). Rats of the 18‐month‐old Sprague Dawley strain with zero, one, two, and three gestations were evaluated for locomotor activity, and Golgi–Cox stain was performed to evaluate the dendritic morphology parameters, the number of dendritic spines, total dendritic length, and branching order number. Adult nulliparous rats (3 months of age) were used as another control group. Adult nulliparous and aging rats with two pregnancies showed an increase in locomotor activity. Adult nulliparous showed an increase in the dendritic spine number compared to old nulliparous rats in both layers of the PFC, the DG, and NAcc. Old rats with two and three pregnancies also showed an increase in the number of dendritic spines compared to old nulliparous rats in layers 3 and 5 of the PFC and in the CA1. Aging animals with one pregnancy also showed an increase in dendritic length compared to old nulliparous rats in the CA1. Our results clearly suggest that two and three pregnancies increase the dendritic spines number in the PFC and CA1 of aged female rats.
A framework for sustainable supply chain in emerging economies
Authors: Queiroz Maciel M.
Published: April 2019

Sustainable supply chains (SSC) are an essential topic in emerging economies for achieving sustainable development. Because of their rapid economic growth, emerging economies are experiencing both sides of this development: the well‐being enhancement and the environmental impact. However, decision makers and practitioners do not have robust models for managing supply networks that consider the sustainability complexities. This study aims to provide a better understanding of SSC in emerging economies and proposes a generic framework to improve the decision‐making process. Based on a review of the literature, a decision framework for sustainability is proposed. A green sustainable decision concept is also discussed in the SSC literature. This study has implications for scholars, decision makers, and practitioners interested in advancing the SSC field based on an extension of the framework.
Bovine brucellosis in Pakistan; an analysis of engagement with risk factors in smallholder farmer settings
Authors: Arif Shumaila , Thomson Peter C. , Hernandez‐Jover Marta , McGill David M. , Warriach Hassan M. , Hayat Khizar , Heller Jane
Published: April 2019

A cross‐sectional study was conducted to estimate the seroprevalence of bovine brucellosis in smallholder farms in seven regions in Pakistan, identify herd and individual level risk factors for seropositivity and assess the level of engagement of farmers with risk factors. In total, 1063 cattle and buffalo belonging to 420 herds in seven districts were sampled. The Rose Bengal test (RBT), indirect enzyme‐linked immunosorbent assay (I‐ELISA) and competitive enzyme‐linked immunosorbent assay (C‐ELISA) were used for the serological diagnosis of bovine brucellosis on all the serum samples. The associations between herd‐and animal‐level risk factors and seropositivity were investigated using logistic regression analyses. In addition, herd management practice scores, created to quantify the number of management practices undertaken that pose a risk for Brucella transmission, were calculated and compared between seropositive and negative herds within each district. Overall herd and animal prevalence were estimated to be 16.2% (95% CI, 13–20%) and 8.7% (95% CI, 7.2–10.6%), respectively, across all districts sampled. Herds with a history of last trimester abortion were found to be more likely to be positive than herds without such history (OR = 2.06, 95% CI, 1.09–3.89), providing validation of our findings and identifying that clinical disease is occurring in this region. It was also identified that herds with five to eight buffalo (OR = 3.80, 95% CI, 1.69–8.49), and those with more than eight buffalo (OR = 3.81, 95% CI, 1.51–9.58) were more likely to be positive for Brucella than those with less (one to two and three to four) buffaloes present in the herd. The presence of other domestic animals at the farm and purchasing animals in last year were found to have no association with seropositivity. The findings of this study support the need for the development of targeted intervention strategies specific to the disease status of each district.
Estimation of offshore extreme wind from wind‐wave coupled modeling
Authors: Larsén Xiaoli Guo , Du Jianting , Bolaños Rodolfo , Imberger Marc , Kelly Mark C. , Badger Merete , Larsen Søren
Published: April 2019

A coupledwind‐wave modeling system is used to simulate 23 years of storms and estimate offshore extreme wind statistics. In this system, the atmospheric Weather Research and Forecasting (WRF) model and Spectral Wave model for Near shore (SWAN) are coupled, through a wave boundary layer model (WBLM) that is implemented in SWAN. The WBLM calculates momentum and turbulence kinetic energy budgets, using them to transfer wave‐induced stress to the atmospheric modeling. While such coupling has a trivial impact on the wind modeling for 10‐m wind speeds less than 20 ms−1, the effect becomes appreciable for stronger winds—both compared with uncoupled WRF modeling and with standard parameterization schemes for roughness length. The coupled modeling output is shown to be satisfactory compared with measurements, in terms of the distribution of surface‐drag coefficient with wind speed. The coupling is also shown to be important for estimation of extreme winds offshore, where the WBLM‐coupled results match observations better than results from noncoupled modeling, as supported by measurements from a number of stations.
Spatiotemporal variability of the wind power resource in Argentina and Uruguay
Authors: Bianchi Emilio , Solarte Andrés , Guozden Tomás
Published: April 2019

The spatiotemporal variability of the wind power resource over Argentina and Uruguay is assessed based on the Modern‐Era Retrospective Analysis for Research and Applications 2 (MERRA2) dataset. Hourly wind speeds were interpolated to 100‐m height, and then, wind power outputs were computed using power curves of three International Electrotechnical Commission (IEC) wind classes. The time series of wind power outputs were filtered using a fast Fourier transform (FFT) to separate regular (annual and daily) from irregular (interannual and synoptic scale) cycles. An empirical orthogonal function analysis was applied to the resulting datasets to obtain the main modes of variability. The results show that the combination of wind power outputs from southern and northern Patagonia broadly follows the average annual electric load. Patagonia exhibits the highest variability on the interannual, annual, and synoptic timescales. On the interannual and synoptic timescales, the variability modes are associated with known and distinct atmospheric circulation modes. The interannual modes of variability are associated with opposite surface level pressure (SLP) anomalies between middle and high latitudes.