bluuebunny/crossref_metadata_2025 huggingface dataset:
The Initial Factors with Strong Predictive Value in Relation to Six-Month Outcome among Patients Operated due to Extra-Axial Hematomas
Authors: Kulesza Bartłomiej , Litak Jakub , Grochowski Cezary , Nogalski Adam , Rola Radosław
Published: March 2020

Introduction: Traumatic brain injuries (TBI) are a real social problem, with an upward trend worldwide. The most frequent consequence of a traumatic brain injury is extra-axial hemorrhage, i.e., an acute subdural (SDH) and epidural hematoma (EDH). Most of the factors affecting the prognosis have been analyzed on a wide group of traumatic brain injuries. Nonetheless, there are few studies analyzing factors influencing the prognosis regarding patients undergoing surgery due to acute subdural and epidural hematoma. The aim of this study was to identify the factors which have the strongest prognostic value in relation to the 6-month outcome of the patients undergoing surgery for SDH and EDH. Patients and methods: The study included a group of 128 patients with isolated craniocerebral injuries. Twenty eight patients were operated upon due to EDH, and a group of 100 patients were operated upon due to SDH. The following factors from the groups were analyzed: demographic data, physiological factors, laboratory factors, computed tomography scan characteristics, and time between the trauma and the surgery. All of these factors were correlated in a multivariate analysis with the six-month outcome in the Glasgow outcome scale. Results: The factors with the strongest prognostic value are GCS score, respiration rate, saturation, glycaemia and systolic blood pressure. Conclusion: Initial GCS score, respiratory rate, saturation, glycaemia and systolic blood pressure were the factors with the strongest prognostic value.
Teacher Training in Intercultural Education: Teacher Perceptions
Authors: Figueredo-Canosa Victoria , Ortiz Jiménez Luis , Sánchez Romero Cristina , López Berlanga María Carmen
Published: March 2020

Background: The aim of the present study was to evaluate teacher perceptions on the training received in intercultural education. Methods: The article presents a quantitative, non- experimental and ex-post-facto type of research; directed to inquire about the perceptions of the teachers of primary education in Andalusia (Spain) in relation to the intercultural training received. Based on the descriptive survey method, two questionnaires were administered to a sample composed of 320 students and 80 teachers. Results: The results show certain strengths of the training teacher programs in the field of interculturality (encouragement of reflection, participation and collaboration …), as well as weaknesses (decontextualization, inflexibility, primacy of theoretical learning, non-transversal character, etc.). Conclusions: Despite strengths, intercultural teacher training continues to be a challenge in Andalusia.
Concept Mapping in the Age of Deleuze: Fresh Perspectives and New Challenges
Authors: Kinchin Ian M. , Gravett Karen
Published: March 2020

This conceptual paper offers a reconsideration of the application of Novakian concept mapping to higher education research by putting to work the Deleuzian concept of the rhizome. We ask: what does thinking with Deleuze’s concepts offer researchers interested in concept mapping, and what conceptual, and terminological, obstacles might be created through such a reconceptualization? We have focused on the rhizomatic principles of mapping and tracing in the context of concept mapping. We contend that Deleuze offers a fresh line of flight with the potential to deterritorialise the discourse surrounding concept mapping, thus widening its applicability and increasing its accessibility to researchers who do not necessarily share the same arborescent concept mapping heritage: with its roots in science education. Exploring the overlap between rhizomatics and concept mapping also allows for the reappraisal and blurring of the boundary between structural and post-structural discourses—breaking down an unproductive binary in the literature.
Access Control Role Evolution Mechanism for Open Computing Environment
Authors: Liu Aodi , Du Xuehui , Wang Na
Published: March 2020

Data resources in open computing environments (including big data, internet of things and cloud computing) are characterized by large scale, wide source, and strong dynamics. Therefore, the user-permission relationship of open computing environments has a huge scale and will be dynamically adjusted over time, which enables effective permission management in the role based access control (RBAC) model to become a challenging problem. In this paper, we design an evolution mechanism of access control roles for open computing environments. The mechanism utilizes the existing user-permission relationship in the current system to mine the access control role and generate the user-role and role-permission relationship. When the user-permission relationship changes, the roles are constantly tuned and evolved to provide role support for access control of open computing environments. We propose a novel genetic-based role evolution algorithm that can effectively mine and optimize roles while preserving the core permissions of the system. In addition, a role relationship aggregation algorithm is proposed to realize the clustering of roles, which provides a supplementary reference for the security administrator to give the role real semantic information. Experimental evaluations in real-world data sets show that the proposed mechanism is effective and reliable.
Smart Handoff Technique for Internet of Vehicles Communication using Dynamic Edge-Backup Node
Authors: Awan Khalid Mahmood , Nadeem Malik , Sadiq Ali Safaa , Alghushami Abdullah , Khan Imran , Rabie Khaled
Published: March 2020

A vehicular adhoc network (VANET) recently emerged in the the Internet of Vehicles (IoV); it involves the computational processing of moving vehicles. Nowadays, IoV has turned into an interesting field of research as vehicles can be equipped with processors, sensors, and communication devices. IoV gives rise to handoff, which involves changing the connection points during the online communication session. This presents a major challenge for which many standardized solutions are recommended. Although there are various proposed techniques and methods to support seamless handover procedure in IoV, there are still some open research issues, such as unavoidable packet loss rate and latency. On the other hand, the emerged concept of edge mobile computing has gained crucial attention by researchers that could help in reducing computational complexities and decreasing communication delay. Hence, this paper specifically studies the handoff challenges in cluster based handoff using new concept of dynamic edge-backup node. The outcomes are evaluated and contrasted with the network mobility method, our proposed technique, and other cluster-based technologies. The results show that coherence in communication during the handoff method can be upgraded, enhanced, and improved utilizing the proposed technique.
Fault Model and Travelling Wave Matching Based Single Terminal Fault Location Algorithm for T-Connection Transmission Line: A Yunnan Power Grid Study
Authors: Shu Hongchun , Han Yiming , Huang Ran , Tang Yutao , Cao Pulin , Yang Bo , Zhang Yu
Published: March 2020

Due to the complex structure of the T-connection transmission lines, it is extremely difficult to identify the reflected travelling wave from the fault point and that from the connection point by the measurement from only one terminal. According to the characteristics of the structure of the T-connection transmission line, the reflection of the travelling wave within the line after the failure of different sections in T-connection transmission line are analyzed. Based on the lattice diagram of the travelling wave, the sequence of travelling waves detected at the measuring terminal varies with the fault distance and the faulty section. Moreover, the sequence of travelling waves detected in one terminal is unique at each faulty section. This article calculates the arrival time of travelling waves of fault points at different locations in different sections to form the collection of the travelling wave arrival time sequence. Then the sequence of travelling waves of the new added fault waveforms is extracted to compare with the sequences in the collection for the faulty section identification and fault location. This proposed method can accurately locate the fault with different fault types, fault resistances and system impedances by only single-terminal fault data. Both Power Systems Computer Aided Design/ Electromagnetic Transients including DC (PSCAD/EMTDC) and actual measurement data are implemented to verify the effectiveness of this method.
Role of the Dominant Species on the Distributions of Neighbor Species in a Subtropical Forest
Authors: Wei Shiguang , Li Lin , Lian Juyu , Nielsen Scott E. , Wang Zhigao , Mao Lingfeng , Ouyang Xuejun , Cao Honglin , Ye Wanhui
Published: March 2020

Understanding the role of dominant species in structuring the distribution of neighbor species is an important part of understanding community assembly, a central goal of ecology. Phylogenetic information helps resolve the multitude of processes driving community assembly and the importance of evolution in the assembly process. In this study, we classified species in a 20-ha subtropical forest in southern China into groups with different degrees of phylogenetic relatedness to the dominant species Castanopsis chinensis. Species surrounding individuals of C. chinensis were sampled in an equal area annulus at six spatial scales, counting the percent of relatives and comparing this to permutation tests of a null model and variance among species groups. The results demonstrated that dominant species affected their relatives depending on community successional stage. Theory would predict that competitive exclusion and density-dependence mechanisms should lead to neighbors that are more distant in phylogeny from C. chinensis. However, in mature forests distant relatives were subjected to competitive repulsion by C. chinensis, while environment filtering led to fewer distant species, regardless of scale. A variety of biological and non-biological factors appear to result in a U-shaped quantitative distribution determined by the dominant species C. chinensis. Scale effects also influenced the dominant species. As a dominant species, C. chinensis played an important role in structuring the species distributions and coexistence of neighbor species in a subtropical forest.
Light Shock Stress after Outdoor Sunlight Exposure in Seedlings of Picea abies (L.) Karst. and Pinus sylvestris L. Pre-Cultivated under LEDs—Possible Mitigation Treatments and Their Energy Consumption
Authors: Hernandez Velasco Marco , Mattsson Anders
Published: March 2020

Year-round cultivation under light emitting diodes (LEDs) has gained interest in boreal forest regions like Fenno-Scandinavia. This concept offers forest nurseries an option to increase seedling production normally restricted by the short vegetation period and the climate conditions. In contrast to some horticultural crops which can be cultivated entirely under LEDs without sunlight, forest seedlings need to be transplanted outdoors in the nursery at a very young age before being outplanted in the field. Juvenile plants are less efficient using absorbed light and dissipating excess energy making them prone to photoinhibition at conditions that usually do not harm mature plants. The outdoor transfer can cause stress in the seedlings due to high sunlight intensity and exposure to ultraviolet (UV) radiation not typically present in the spectra of LED lamps. This study tested possible treatments for mitigating light shock stress in seedlings of Picea abies (L.) Karst. and Pinus sylvestris L. transplanted from indoor cultivation under LEDs to outdoor sunlight exposure. Three sowings were carried out in 2014 (May and June) and 2015 (May) cultivating the seedlings during five weeks under LED lights only. Afterwards, higher light intensity or UV radiation treatments were applied during one week in order to adapt the seedlings to natural outdoor conditions. After transplanting a transition phase was introduced using shading cloths for one or three weeks as outdoor treatments for light shock mitigation. Chlorophyll fluorescence (ChlF) levels and CO2 assimilation rates were measured before transplanting and followed outdoors during 5 weeks. The ChlF results revealed stress symptoms in the photoreceptors during the first days after transplanting. After five weeks outdoors the ChlF levels had recovered and the light saturation points had shifted, allowing higher CO2 assimilation rates. By the end of the vegetation period the morphological attributes showed no major differences between treatments.
Root Litter Mixing with That of Japanese Cedar Altered CO2 Emissions from Moso Bamboo Forest Soil
Authors: Pan Jun , Liu Yuanqiu , Yuan Xinyue , Xie Junyi , Niu Jiehui , Fang Haifu , Wang Baihui , Liu Wei , Deng Wenping , Kong Fanqian , Liu Chunmei , Zhang Ling
Published: March 2020

Research Highlights: This study examined the effect of mixing fine roots of Japanese cedar with moso bamboo on soil carbon dioxide (CO2) emissions with nitrogen (N) addition treatment. Background and Objectives: Moso bamboo expansion into adjacent forests and N deposition are common in subtropical China. The effects of litter input on soil CO2 emissions, especially fine root litter input, are crucial to evaluate contribution of moso bamboo expansion on greenhouse gas emissions. Materials and Methods: An in situ study over 12 months was conducted to examine mixing fine roots of Japanese cedar with moso bamboo on soil CO2 emissions with simulated N deposition. Results: Fine root litter input of Japanese cedar and moso bamboo both impacted soil CO2 emission rates, with mixed litter, positively impact soil CO2 emission rate with N addition treatment. Moso bamboo fine root litter input decreased the sensitivity of soil CO2 emission rate to soil temperature. Conclusions: The encroachment of moso bamboo into adjacent forests might benefit soil C sequestration under warming climate, which will also benefit the mitigation of global climate change.
Health Disparities and Cardiovascular Disease
Authors: Niakouei Ava , Tehrani Minoo , Fulton Lawrence
Published: March 2020

The number one leading cause of death in 2017 for Americans was cardiovascular disease (CVD), and health disparities can exacerbate risks. This study evaluates the 2018 Behavioral Risk Factor Surveillance System (BRFSS) (n = 437,436) to estimate population risks for behavioral, socio-economic, psychological, and biological factors. A general linear model with a quasi-binomial link function indicated higher risks for the following groups: smokers (odds ratio, OR = 0.688), individuals with higher body mass index scores (OR = 1.023), persons unable to work (OR = 2.683), individuals with depression (OR = 1.505), workers who missed more days due to mental issues (OR = 1.12), the elderly, males (OR = 1.954), those in race categories “indigenous Americans, Alaskan non-Hispanics”, “Black Hispanics,” or “other, non-Hispanic,” and individuals with lower income. Surprisingly, increased consumption of alcohol was not found to be a risk factor as in other studies. Additional study of alcohol risk factors is needed. Further, Black non-Hispanics were associated with lower rates of CVD/MI (myocardial infarction), a finding that is supported by recent evidence of more unhealthy behaviors in other races. The results of this study highlight 2018 CVD/MI disparities based on the BRFSS and suggest the need for additional policy interventions including education and providing increased access to health care for the disadvantaged. The principles of beneficence and justice require policy interventions such as these.
Potential Impacts of Climate Change on Extreme Weather Events in the Niger Delta Part of Nigeria
Authors: Hassan Ibrahim , Kalin Robert M. , Aladejana Jamiu A. , White Christopher J.
Published: March 2020

The Niger Delta is the most climate-vulnerable region in Nigeria. Flooding events are recorded annually in settlements along the River Niger and its tributaries, inundating many towns and displacing people from their homes. In this study, climate change impacts from extreme meteorological events over the period 2010–2099 are predicted and analyzed. Four coupled model intercomparison project phase 5 (CMIP5) global climate models (GCMs) under respectively concentration pathways (RCP4.5 and RCP8.5) emission scenarios were used for climate change predictions. Standardized precipitation indices (SPI) of 1-month and 12-month time steps were used for extreme event assessment. Results from the climate change scenarios predict an increase in rainfall across all future periods and under both emission scenarios, with the highest projected increase during the last three decades of the century. Under the RCP8.5 emission scenario, the rainfall at Port Harcourt and Yenagoa Stations is predicted to increase by about 2.47% and 2.62% while the rainfall at Warri Station is predicted to increase by about 1.39% toward the end of the century. The 12-month SPI under RCP4.5 and RCP8.5 emission scenarios predict an exceedance in the extreme wet threshold (i.e., SPI > 2) during all future periods and across all study locations. These findings suggest an increasing risk of flooding within the projected periods. The finding can be useful to policymakers for the formulation and planning of flood mitigation and adaptation measures.
On the Performance of Battery-Assisted PS-SWIPT Enabled DF Relaying
Authors: Liu Zhipeng , Lu Guangyue , Ye Yinghui , Shi Liqin
Published: March 2020

Compared with the conventional simultaneous wireless information and power transfer (SWIPT) based relaying with “harvest-then-forward” protocol, the battery-assisted SWIPT relaying is more practical and powerful due to the joint use of the harvested energy and supplementary battery. However, to the best of our knowledge, the performance of a battery-assisted power splitting (PS)-SWIPT decode-and-forward (DF) relay system has not been studied. In this paper, for a given amount of energy from the relay’s battery, we propose to maximize the outage and ergodic capacities by optimizing the static and dynamic PS ratios that rely on statistical and instantaneous channel state information (CSI), respectively, and derive their corresponding outage and ergodic capacities. Computer simulations validate our analytical results and demonstrate the advantages of the dynamic PS over the static PS in terms of the outage and ergodic capacities, as well as the energy efficiency.
Privacy Preserving Data Publishing for Multiple Sensitive Attributes Based on Security Level
Authors: Xiao Yuelei , Li Haiqi
Published: March 2020

Privacy preserving data publishing has received considerable attention for publishing useful information while preserving data privacy. The existing privacy preserving data publishing methods for multiple sensitive attributes do not consider the situation that different values of a sensitive attribute may have different sensitivity requirements. To solve this problem, we defined three security levels for different sensitive attribute values that have different sensitivity requirements, and given an L s l -diversity model for multiple sensitive attributes. Following this, we proposed three specific greed algorithms based on the maximal-bucket first (MBF), maximal single-dimension-capacity first (MSDCF) and maximal multi-dimension-capacity first (MMDCF) algorithms and the maximal security-level first (MSLF) greed policy, named as MBF based on MSLF (MBF-MSLF), MSDCF based on MSLF (MSDCF-MSLF) and MMDCF based on MSLF (MMDCF-MSLF), to implement the L s l -diversity model for multiple sensitive attributes. The experimental results show that the three algorithms can greatly reduce the information loss of the published microdata, but their runtime is only a small increase, and their information loss tends to be stable with the increasing of data volume. And they can solve the problem that the information loss of MBF, MSDCF and MMDCF increases greatly with the increasing of sensitive attribute number.
Logic-Based Technologies for Intelligent Systems: State of the Art and Perspectives
Authors: Calegari Roberta , Ciatto Giovanni , Denti Enrico , Omicini Andrea
Published: March 2020

Together with the disruptive development of modern sub-symbolic approaches to artificial intelligence (AI), symbolic approaches to classical AI are re-gaining momentum, as more and more researchers exploit their potential to make AI more comprehensible, explainable, and therefore trustworthy. Since logic-based approaches lay at the core of symbolic AI, summarizing their state of the art is of paramount importance now more than ever, in order to identify trends, benefits, key features, gaps, and limitations of the techniques proposed so far, as well as to identify promising research perspectives. Along this line, this paper provides an overview of logic-based approaches and technologies by sketching their evolution and pointing out their main application areas. Future perspectives for exploitation of logic-based technologies are discussed as well, in order to identify those research fields that deserve more attention, considering the areas that already exploit logic-based approaches as well as those that are more likely to adopt logic-based approaches in the future.
Larvicidal and Repellent Activity of Mentha arvensis L. Essential Oil against Aedes aegypti
Authors: Manh Ho Dung , Tuyet Ong Thi
Published: March 2020

Dengue is one of the most dangerous vector-borne diseases transmitted by Aedes mosquitoes. The use of mosquito repellents to protect human hosts and insecticides to reduce the mosquito population is a crucial strategy to prevent the disease. Here, we reported larvicidal and repellent activities of Mentha arvensis L. essential oil against Aedes aegypti, the main vector of the disease. The essential oil was extracted by hydro-distillation from the aromatic plant grown in Vietnam. The yield was 0.67% based on the weight of fresh leaves. The essential oil was analyzed by gas chromatography-mass spectrometry (GC-MS). The main components were menthol (66.04%), menthyl acetate (22.19%), menthone (2.51%), and limonene (2.04%). Toxicity test on Aedes aegypti larvae showed that the median lethal concentrations, LC50 and LC90 were 78.1 ppm (part per million) and 125.7 ppm, respectively. Besides, the essential oil showed excellent repellency on Aedes aegypti mosquitoes. At 25%, 50%, and 100% concentration, the respective complete protection times (CPTs) were 45 min, 90 min, and 165 min. When adding 5% vanillin to the essential oil (25%), the complete protection time of the essential oil increased up to 120 min. In conclusion, the EO from Mentha arvensis L. has been shown to be a promising natural larvicide and repellent against Aedes aegypti mosquitoes.
Energy Resolved Neutron Imaging for Strain Reconstruction Using the Finite Element Method
Authors: Aggarwal Riya , Meylan Michael H. , Lamichhane Bishnu P. , Wensrich Chris M.
Published: March 2020

A novel pulsed neutron imaging technique based on the finite element method is used to reconstruct the residual strain within a polycrystalline material from Bragg edge strain images. This technique offers the possibility of a nondestructive analysis of strain fields with a high spatial resolution. The finite element approach used to reconstruct the strain uses the least square method constrained by the conditions of equilibrium. This inclusion of equilibrium makes the problem well-posed. The procedure is developed and verified by validating for a cantilevered beam problem. It is subsequently demonstrated by reconstructing the strain from experimental data for a ring-and-plug sample, measured at the spallation neutron source RADEN at J-PARC in Japan. The reconstruction is validated by comparison with conventional constant wavelength strain measurements on the KOWARI diffractometer at ANSTO in Australia. It is also shown that the addition of a Tikhonov regularisation scheme further improves the reconstruction.
A Stereolithographic Model-Based Dense Body Plan Generation Method to Construct a Ship Hydrodynamic Coefficients Database
Authors: Jing Qianfeng , Shen Helong , Yin Yong
Published: March 2020

A ship’s body plan is a vital data resource of ship hydrodynamics analysis, especially for time-domain simulations. Motivated by 3D printing technology, a novel dense body plan generation method is developed in this study. The slicing algorithm is adopted to generate dense 2D body plans from ship stereolithographic models. The dense body plan can be produced automatically under arbitrary rotational angles and slices. Moreover, a section redistribution algorithm is integrated to eliminate the non-uniform distribution features in sliced data inherited from the stereolithographic models. The benchmark ship models are selected to validate the accuracy of the method. The hull volumes of three ship models are calculated based on the produced data. The calculated results show satisfactory agreement with the published values. Furthermore, the estimation formulas of wetted surface area (WSA) are reviewed and utilized for validation. The calculated WSAs by slice integration turn out to be adaptive and accurate. The time costs of different slices are provided to illustrate the computational efficiency. A ship hydrodynamic coefficients database is constructed based on a 2D strip method and the produced data. The proposed method aims to improve the generation process of the body plan, which could meet the accuracy requirements of the strip method. As a result, hydrodynamic coefficients utilized in time-domain simulations could be obtained smoothly from the database.
Association Between the Cerebral Autoregulation Index (Pressure Reactivity), Patient’s Clinical Outcome, and Quality of ABP(t) and ICP(t) Signals for CA Monitoring
Authors: Bajpai Basant K. , Preiksaitis Aidanas , Vosylius Saulius , Rocka Saulius
Published: March 2020

Background and Objectives: The aim of this study was to explore the association between the cerebral autoregulation (CA) index, the pressure reactivity index (PRx), the patient’s clinical outcome, and the quality of arterial blood pressure (ABP(t)) and intracranial blood pressure (ICP(t)) signals by comparing two filtering methods to derive the PRx. Materials and Methods: Data from 60 traumatic brain injury (TBI) patients were collected. Moving averaging and FIR (Finite Impulse Response) filtering were performed on the ABP(t) and ICP(t) signals, and the PRx was estimated from both filtered datasets. Sensitivity, specificity, and receiver-operating characteristic (ROC) curves with the area under the curves (AUCs) were determined using patient outcomes as a reference. The outcome chosen for comparison among the two filtering methods were mortality and survival. Results: The FIR filtering approach, compared with clinical outcome, had a sensitivity of 70%, a specificity of 81%, and a level of significance p = 0.001 with an area under the curve (AUC) of 0.78. The moving average filtering method compared with the clinical outcome had a sensitivity of 58%, a specificity of 72%, and a level of significance p = 0.054, with an area under the curve (AUC) of 0.66. Conclusions: The FIR (optimal) filtering approach was found to be more sensitive for discriminating between two clinical outcomes, namely intact (survival) and impaired (death) cerebral autoregulation for TBI treatment decision making.
Potentiodynamic and Galvanodynamic Regimes of Mass Transfer in Flow-Through Electrodialysis Membrane Systems: Numerical Simulation of Electroconvection and Current-Voltage Curve
Authors: Uzdenova Aminat , Urtenov Makhamet
Published: March 2020

Electromembrane devices are usually operated in two electrical regimes: potentiodynamic (PD), when a potential drop in the system is set, and galvanodynamic (GD), when the current density is set. This article theoretically investigates the current-voltage curves (CVCs) of flow-through electrodialysis membrane systems calculated in the PD and GD regimes and compares the parameters of the electroconvective vortex layer for these regimes. The study is based on numerical modelling using a basic model of overlimiting transfer enhanced by electroconvection with a modification of the boundary conditions. The Dankwerts’ boundary condition is used for the ion concentration at the inlet boundary of the membrane channel. The Dankwerts’ condition allows one to increase the accuracy of the numerical implementation of the boundary condition at the channel inlet. On the CVCs calculated for PD and DG regimes, four main current modes can be distinguished: underlimiting, limiting, overlimiting, and chaotic overlimiting. The effect of the electric field regime is manifested in overlimiting current modes, when a significant electroconvection vortex layer develops in the channel.
Synthesis of Silica Membranes by Chemical Vapor Deposition Using a Dimethyldimethoxysilane Precursor
Authors: Oyama S. Ted , Aono Haruki , Takagaki Atsushi , Sugawara Takashi , Kikuchi Ryuji
Published: March 2020

Silica-based membranes prepared by chemical vapor deposition of tetraethylorthosilicate (TEOS) on γ-alumina overlayers are known to be effective for hydrogen separation and are attractive for membrane reactor applications for hydrogen-producing reactions. In this study, the synthesis of the membranes was improved by simplifying the deposition of the intermediate γ-alumina layers and by using the precursor, dimethyldimethoxysilane (DMDMOS). In the placement of the γ-alumina layers, earlier work in our laboratory employed four to five dipping-calcining cycles of boehmite sol precursors to produce high H2 selectivities, but this took considerable time. In the present study, only two cycles were needed, even for a macro-porous support, through the use of finer boehmite precursor particle sizes. Using the simplified fabrication process, silica-alumina composite membranes with H2 permeance > 10−7 mol m−2 s−1 Pa−1 and H2/N2 selectivity >100 were successfully synthesized. In addition, the use of the silica precursor, DMDMOS, further improved the H2 permeance without compromising the H2/N2 selectivity. Pure DMDMOS membranes proved to be unstable against hydrothermal conditions, but the addition of aluminum tri-sec-butoxide (ATSB) improved the stability just like for conventional TEOS membranes.
Formation and Thermal Stability of ω-Ti(Fe) in α-Phase-Based Ti(Fe) Alloys
Authors: Kriegel Mario J. , Rudolph Martin , Kilmametov Askar , Straumal Boris B. , Ivanisenko Julia , Fabrichnaya Olga , Hahn Horst , Rafaja David
Published: March 2020

In this work, the formation and thermal stability of the ω-Ti(Fe) phase that were produced by the high-pressure torsion (HPT) were studied in two-phase α-Ti + TiFe alloys containing 2 wt.%, 4 wt.% and 10 wt.% iron. The two-phase microstructure was achieved by annealing the alloys at 470 °C for 4000 h and then quenching them in water. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were utilized to characterize the samples. The thermal stability of the ω-Ti(Fe) phase was investigated using differential scanning calorimetry (DSC) and in situ high-temperature XRD. In the HPT process, the high-pressure ω-Ti(Fe) phase mainly formed from α-Ti. It started to decompose by a cascade of exothermic reactions already at temperatures of 130 °C. The decomposition was finished above ~320 °C. Upon further heating, the phase transformation proceeded via the formation of a supersaturated α-Ti(Fe) phase. Finally, the equilibrium phase assemblage was established at high temperatures. The eutectoid temperature and the phase transition temperatures measured in deformed and heat-treated samples are compared for the samples with different iron concentrations and for samples with different phase compositions prior to the HPT process. Thermodynamic calculations were carried out to predict stable and metastable phase assemblages after heat-treatments at low (α-Ti + TiFe) and high temperatures (α-Ti + β-(Ti,Fe), β-(Ti,Fe)).
Role of Ag+ in the Bioleaching of Arsenopyrite by Acidithiobacillus ferrooxidans
Authors: Zhang Yan , Li Qian , Liu Xiaoliang
Published: March 2020

Arsenopyrite (FeAsS) is often associated with gold, but pre-treatment is necessary prior to gold leaching, mainly due to the gold encapsulation in the matrix of FeAsS. Bio-oxidation is attractive and promising, largely due to its simplicity, low cost and environmental friendliness. A critical problem that still impedes the large-scale applications of this green technology is its slow leaching kinetics. Some metal ions such as Ag+ have previously been found to expedite the bioleaching process. In this paper, the role of Ag+ in the arsenopyrite bioleaching by Acidithiobacillus ferrooxidans was investigated in detail by bioleaching experiments and a series of analyses including thermodynamics, X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Experimental results suggested that addition of 5 mg/L Ag+ to the leaching system could significantly improve the final As leaching efficiency from 30.4% to 47.8% and shorten the bioleaching period from 19 days to 15 days. Thermodynamic analysis indicates that Ag+ destabilises As2S2, As2S3 and S0 via forming Ag2S, which is confirmed by the XRD analysis on the phase transformation during bioleaching. SEM and XPS analyses further showed that Ag+ removed the passivating film consisting mainly of As2S2, As2S3 and S0 because Ag2S formed on the arsenopyrite surface from the start bioleaching of 36 h. In the presence of Fe3+, Ag2S could easily be dissolved to Ag+ again, likely leading to the establishment of the Ag+/Ag2S cycle. The bacteria utilised the two synergistic cycles of Fe3+/Fe2+ and Ag+/Ag2S to catalyse the bioleaching of arsenopyrite.
Effects of ATIG Welding on Weld Shape, Mechanical Properties, and Corrosion Resistance of 430 Ferritic Stainless Steel Alloy
Authors: Touileb Kamel , Ouis Abousoufiane , Djoudjou Rachid , Hedhibi Abdeljlil Chihaoui , Alrobei Hussein , Albaijan Ibrahim , Alzahrani Bandar , Sherif El-Sayed M. , Abdo Hany S.
Published: March 2020

Flux activated tungsten inert gas (ATIG) welding is a variant of tungsten inert gas (TIG) welding process with high production efficiency, high quality, low energy consumption, and low cost. The study of activating flux mechanism by increasing weld penetration has direct significance in developing flux and welding process. This study has been conducted on 430 ferritic stainless steel alloy. Design of experiment is used to get the best formulation of flux. Based on Minitab17 software, nineteen compositions of flux were prepared using the mixing method. Fluxes are combinations of three oxides (MoO3-TiO2-SiO2). Using the optimizer module available in Minitab 17 software, the best formulation was obtained to achieve the best weld depth. Hence, the obtained depth is twice greater than that achieved by conventional TIG welding. Moreover, mechanical properties and corrosion resistance have been investigated for TIG and ATIG welds respectively in tensile, impact, and hardness tests, and in potentiodynamic polarization measurement test.
Comparative Study of Laser-Arc Hybrid Welding for AA6082-T6 Aluminum Alloy with Two Different Arc Modes
Authors: Han Xiaohui , Yang Zhibin , Ma Yin , Shi Chunyuan , Xin Zhibin
Published: March 2020

The effects of arc modes on laser-arc hybrid welding for AA6082-T6 aluminum alloy were comparatively studied. Two arc modes were employed: pulsed metal inert gas arc and cold metal transfer arc. The results indicated that joints without porosity, undercutting, or other defects were obtained with both laser-pulsed metal inert gas hybrid welding (LPMHW) and laser-cold metal transfer hybrid welding (LCHW). Spatter was reduced, and even disappeared, during the LCHW process. The sizes of equiaxed dendrites and the width of the partially melted zone in the LPMHW joint were larger than those in the LCHW joint. The microhardness in each zone of the LPMHW joint was lower than that of the LCHW joint. The softening region in the heat-affected zone of the LPMHW joint was wider than that of the LCHW joint. The tensile strength of the LCHW joint was higher than that of the LPMHW joint. For the two joints, the fractures all occurred in the softening region in the heat-affected zone, and the fracture morphologies showed ductile fracture features. The dimples in the fractograph of the LCHW joint were deeper than those of the LPMHW joint.
A Flow-Through Microfluidic Relative Permittivity Sensor
Authors: Zeng Yaxiang , Sanders Remco , Wiegerink Remco , Lötters Joost
Published: March 2020

In this paper, we present the design, simulation, fabrication and characterization of a microfluidic relative permittivity sensor in which the fluid flows through an interdigitated electrode structure. Sensor fabrication is based on an silicon on insulator (SOI) wafer where the fluidic inlet and outlet are etched through the handle layer and the interdigitated electrodes are made in the device layer. An impedance analyzer was used to measure the impedance between the interdigitated electrodes for various non-conducting fluids with a relative permittivity ranging from 1 to 41. The sensor shows good linearity over this range of relative permittivity and can be integrated with other microfluidic sensors in a multiparameter chip.
The Origin and Evolution of Ore-Bearing Rocks in the Loypishnun Deposit (Monchetundra Massif, NE Fennoscandian Shield): Isotope Nd-Sr and REE Geochemical Data
Authors: Kunakkuzin Evgeniy , Borisenko Elena , Nerovich Luydmila , Serov Pavel , Bayanova Tamara , Elizarov Dmitry
Published: March 2020

The Monchetundra massif is located in the north-eastern Fennoscandian Shield and refers to Paleoproterozoic massifs of the East-Scandinavian Large Igneous Province. The general section of the massif comprises two parts, the lower norite-orthopyroxenite and the upper mafic zones. The lower zone is of great interest due to its associated industrial platinum group elements (PGE) mineralization. The structure and peculiar features of rocks in the lower zone were studied using a drill core from the borehole MT-70 in the south-eastern slope of the Monchetundra massif intersecting the ore zone 1 of the Loypishnun deposit (according to the CJSC Terskaya Mining Company data). A comparison of the barren and ore-bearing varieties of norites and pyroxenites in the Loypishnun deposit shows that the ore samples have the lowest negative εNd values, a relatively more differentiated distribution spectrum with the Light rare earth elements (LREE) dominating over the Heavy REE (HREE), Eu/Eu* ≥ 1, and a higher mean content of alkali and large-ion lithophile elements (Ba, Rb, and Cs). New geochemical data indicated an origin of magmas for rocks from a layered series in the Loypishnun deposit by a high degree of melting of a LREE-rich source with a low mean content of REE. Negative εNd values, low ISr values, and a marked negative Nb indicate that the crustal material affected the evolution of rocks in the lower zone of the massif more than in the upper zone. The formation of ore bodies in the Loypishnun deposit was governed by the crust-mantle interaction, magmatic differentiation, and association with the most differentiated varieties, and by further concentration of the ore at the late and post-magmatic stages in a highly permeable environment for fluids in the Monchetundra fault zone.
Virus-Based Nanomaterials and Nanostructures
Authors: Oh Jin-Woo , Han Dong-Wook
Published: March 2020

This Special Issue highlights the recent developments and future directions of virus-based nanomaterials and nanostructures in energy and biomedical applications. The virus-based biomimetic materials formulated using innovative ideas presented herein are characterized for the applications of biosensors and nanocarriers. The research contributions and trends based on virus-based materials, covering energy-harvesting devices to tissue regeneration over the last two decades, are described and discussed.
Biocompatible Ag/Fe-Enhanced TiO2 Nanoparticles as an Effective Compound in Sunscreens
Authors: Nicoara Adrian Ionut , Ene Vladimir Lucian , Voicu Bianca Beatrice , Bucur Mihaela Adriana , Neacsu Ionela Andreea , Vasile Bogdan Stefan , Iordache Florin
Published: March 2020

In this work, valuable biocompatible Ag/Fe-enhanced TiO2 nanoparticles are comparatively prepared by a conventional wet chemistry method (sol-gel) and a rapid, efficient, hybrid unconventional method (microwave-assisted hydrothermal synthesis). In order to establish their application as effective compounds in sunscreens, the obtained powders were first structurally and morphologically characterized, analyses from which their nanodimensional character, crystalline structure and thermal behavior were highlighted. The evaluation of sunscreen effectiveness is based on the determination of the sun protection factor (SPF). It was observed that silver enhancing increases the SPF significantly, especially when compared to the pristine samples. The obtained Ag/Fe-enhanced TiO2 powders were also evaluated from the point of view of their biocompatibility on amniotic fluid stem cells, and the results indicated an enhance of cell proliferation when exposed to the synthesized nanostructures.
Influence of Cu2+, Ni2+, and Zn2+ Ions Doping on the Structure, Morphology, and Magnetic Properties of Co-Ferrite Embedded in SiO2 Matrix Obtained by an Innovative Sol-Gel Route
Authors: Dippong Thomas , Levei Erika Andrea , Deac Iosif Grigore , Neag Emilia , Cadar Oana
Published: March 2020

This paper presents the synthesis of metal doped Co ferrites, M0.2Co0.8Fe2O4 (M = Cu2+, Ni2+, and Zn2+) embedded in SiO2 matrix by an innovative sol-gel route. The structural and morphological characterization provided information about the crystalline phases, crystallite size, and the shape of the prepared ferrites. The thermal study depicted the thermal decomposition and stability of the obtained ferrites. X-ray diffraction indicated nanocrystalline ferrites with spinel structure and the lack of crystalline phase impurities, while Fourier transform infrared spectroscopy revealed the presence of functional groups in precursors and ferrite powders. The lattice parameters showed a gradual increase indicating a uniform distribution of divalent metal ions in the Co ferrite lattice. The crystallite size, magnetic moment, super-exchange and deflection of magnetic domain were influenced by the dopant metal ion. The room temperature magnetization indicated a ferromagnetic behavior of the ferrites annealed at 1000 °C and a superparamagnetic behavior of the ferrites annealed at 700 °C.
Association of Coffee, Decaffeinated Coffee and Caffeine Intake from Coffee with Cognitive Performance in Older Adults: National Health and Nutrition Examination Survey (NHANES) 2011–2014.
Authors: Dong Xue , Li Shiru , Sun Jing , Li Yan , Zhang Dongfeng
Published: March 2020

The aim of this study was to examine the association of coffee, caffeinated coffee, decaffeinated coffee and caffeine intake from coffee with cognitive performance in older adults. we used data from the National Health and Nutrition Examination Survey (NHANES) 2011–2014. Coffee and caffeine intake were obtained through two 24-hour dietary recalls. Cognitive performance was evaluated by the Consortium to Establish a Registry for Alzheimer’s Disease (CERAD) test, Animal Fluency test and Digit Symbol Substitution Test (DSST). Binary logistic regression and restricted cubic spline models were applied to evaluate the association of coffee and caffeine intake with cognitive performance. A total of 2513 participants aged 60 years or older were included. In the fully adjusted model, compared to those reporting no coffee consumption, those who reported 266.4–495 (g/day) had a multivariate adjusted odd ratio (OR) with 95% confidence interval (CI) of 0.56(0.35–0.89) for DSST test score, compared to those reporting no caffeinated coffee consumption, those who reported ≥384.8 (g/day) had a multivariate-adjusted OR (95% CI) of 0.68(0.48–0.97) for DSST test score, compared to the lowest quartile of caffeine intake from coffee, the multivariate adjusted OR (95% CI) of the quartile (Q) three was 0.62(0.38–0.98) for the CERAD test score. L-shaped associations were apparent for coffee, caffeinated coffee and caffeine from coffee with the DSST test score and CERAD test score. No significant association was observed between decaffeinated coffee and different dimensions of cognitive performance. Our study suggests that coffee, caffeinated coffee and caffeine from coffee were associated with cognitive performance, while decaffeinated coffee was not associated with cognitive performance.
High-intensity Interval Training Promotes the Shift to a Health-Supporting Dietary Pattern in Young Adults
Authors: Donati Zeppa Sabrina , Sisti Davide , Amatori Stefano , Gervasi Marco , Agostini Deborah , Piccoli Giovanni , Bertuccioli Alexander , Rocchi Marco B.L. , Stocchi Vilberto , Sestili Piero
Published: March 2020

A healthy lifestyle is based on a correct diet and regular exercise. Little is known about the effect of different types of exercise on dietary preferences. To address the question of whether high-intensity interval training (HIIT) could modulate spontaneous food choices, an experimental study was carried out on 32 young, healthy normal-weight subjects. The spontaneous diet of each subject has been monitored over nine weeks of indoor-cycling training, divided into three mesocycles with an incremental pattern: total energy intake, macronutrients and micronutrients have been analysed. A two-way mixed model has been used to assess differences in dietary variables; a principal factor analysis has been performed to identify sample subgroups. An increased energy intake (+17.8% at T3; p < 0.01) has been observed, although macronutrients’ proportions did not vary over time, without differences between sexes. An increase of free fat mass was found in the last mesocycle (+3.8%), without an augmentation of body weight, when, despite the increased training load, a stabilization of energy intake occurred. Three different subgroups characterized by different dietary modifications could be identified among participants that showed a common trend towards a healthier diet. Nine weeks of HIIT promoted a spontaneous modulation of food choices and regulation of dietary intake in young normal-weight subjects aged 21–24. Importantly, this life-period is critical to lay the foundation of correct lifestyles to prevent metabolic diseases and secure a healthy future with advancing age.