bluuebunny/crossref_metadata_2025 huggingface dataset:
A model for integrating work safety into the design of technical equipments
Authors: Moraru Roland Iosif , Bǎbuţ Gabriel Bujor , Popescu – Stelea Mihai , Morar Marius Simion
Published: August 2019

The paper proposes a model unfolded for occupational safety aspects inclusion in the design and management of change stages for a piece of machinery. The “Integrated Safety - Technical Equipment” (ISTE) model substantiates a logical connection between various task-based features to be fulfilled, hazardous areas and occurrences, hazards, risk assessment, ways to wedge in, workplace characteristics, the effect of the working environment, work crew as well as apparatus, tools and/or basically corresponding to and following a set of prior theoretically grounded guidelines, found in literature. At the same time, the paper gives the outline of the case study performed to give proof of the practical model’s, illustrating operational safety design for a mechanical press line, used for sheet metal milling. Resorting to the developed model, it was performed the design, construction and assembling of the automatic press line which is compliant in terms of occupational safety.
Research on the phenomenon of explosive gas occurrence in drills for an engineering building-Case study -
Authors: Tomescu Cristian , Cioclea Doru , Chiuzan Emeric , Matei Adrian , Dragoescu Răzvan
Published: August 2019

The security status indicator in a work system is characterized by safety levels or by risk levels. One of the types of risks in the workplace is the risk of explosion that is part of the risk factors specific to the working environment - chemical risk factors. The works of consolidating and arranging the infrastructure of a motorway include in their scheme the execution of a series of vertical geotechnical drills of the rock stratigraphic column on which is placed the construction and drillings dimensioned at certain depths and diameters which are concreted in order to ensure the load of the upper structure of the building. In some of these drills there has been a phenomenon of occurrence of gases that, within certain concentration limits, are explosive and create a state of danger by producing an explosion inside them, which by propagating to the surface can affect the safety of workers and means for work. This paper is a case study at a workplace of a trading company specializing in construction and proposes an analysis of the causes of explosive gases occurrence, work environment monitoring, and solutions for diminishing the OHS risk factors.
Importance of knowledge in the process of shaping the entrepreneurial attitudes of young people
Authors: Siemieniak Paulina , Rembiasz Małgorzata
Published: August 2019

The article presents the results of author’s research on entrepreneurship of technical university students. The key issue and the aim of the research was to determine the levels of knowledge necessary to run a business, in particular legal knowledge and the establishment and management of own enterprises. The analysis of secondary data and the results of previous research reveal, among others, discrepancy in the opinions of students and current entrepreneurs on the importance of business knowledge, a sense of insufficient knowledge of entrepreneurship (interestingly) also declared by students of economic faculties or lack of information on financing their own business despite going to economics studies. The research tool was an original auditorial survey. The test method was a test of knowledge and a self-report questionnaire. The obtained results were subjected to statistical analysis. The premise of an in-depth analysis of the subject matter is the social need to effectively shape the entrepreneurial attitudes of young people. Utilizing the potential of each individual contributes to the growth of social well-being. The use of the potential of students of management departments at technical universities seems particularly justified, as graduates are supposed to have both industry and technical knowledge as well as business knowledge. In the articles, the authors distinguish areas and present results that may contribute to the debate on the subject of entrepreneurship education at universities.
Competencies in the education of potential entrepreneurs. Research among students of technical faculties
Authors: Rembiasz Małgorzata
Published: August 2019

The aim of the article is to present the basic competencies of entrepreneurs in the contemporary market economy and to compare them with the knowledge, skills and attitudes of potential entrepreneurs, i.e. students of technical universities. The research tool used was an original questionnaire. The obtained results were subjected to statistical analysis. The declared intention to run one’s own business was compared to the declared ability to write a business plan. The results of the research presented in the article were compared with the author’s previous study into shaping entrepreneurial attitudes among students. It should be noted that, in engineering faculties, competence in entrepreneurship, management and economics is sometimes considered unnecessary. It seems, however, that the relevant knowledge gained in high school is insufficient. Young people should have a sound understanding of the principles governing the market economy and the mechanisms at work in the labour market. They should have basic legal knowledge, be able to manage and motivate people as well as plan their own business. The results of the presented research make it possible to identify the competence gap and, potentially, create entrepreneurship education programmes for technical universities.
Geburt eines Fohlens nach Besamung mit tiefgefrorenen
Nebenhodenspermien und zeitgleicher intrauteriner Verabreichung von homologem
Seminalplasma
Authors: Neuhauser Stefanie , Gösele Patricia , Handler Johannes
Published: August 2019

Die Tiefgefrierkonservierung von Nebenhodenspermien stellt eine gute Möglichkeit
zur Erhaltung der Genreserve wertvoller Vatertiere dar, wenn ein plötzlicher
Unfall eine herkömmliche Samengewinnung unmöglich macht. Im vorliegenden Fall
wird von der Geburt eines gesunden Fohlens berichtet, das aus der Besamung mit
Nebenhodenspermien entstand. Die Hoden und Nebenhoden wurden in
Allgemeinanästhesie entfernt und gekühlt über Nacht in das Labor verbracht.
Durch retrograde Spülung der Nebenhodenschwänze konnten 17,79 × 109
Spermien konserviert werden. Eine fruchtbare Stute wurde 1 Jahr später mit
tiefgefrorenen Nebenhodenspermien tief intrauterin besamt. Im 1. Zyklus wurde
die Stute nicht tragend. Im 2. Zyklus wurde homologes Seminalplasma zusammen mit
den Nebenhodenspermien in den Uterus verbracht und 14 Tage nach der Ovulation
konnte eine Trächtigkeit festgestellt werden. Nach einer Graviditätsdauer von
334 Tagen wurde ein gesundes Hengstfohlen geboren. Die Vorbereitung von Hoden
und Nebenhoden nach einem Unfall oder Todesfall für die weitere Bearbeitung im
Labor und die einzelnen Arbeitsschritte für die Aufbereitung von
Nebenhodenspermien werden beschrieben.
Eccentric-concentric Ratio: A Key Factor for Defining Strength Training in Soccer
Authors: Nuñez F. Javier , Hoyo Moisés de , López Alejandro Muñoz , Sañudo Borja , Otero-Esquina Carlos , Sanchez Hugo , Gonzalo-Skok Oliver
Published: August 2019

The aims of this study were to analyse the effect of chronic strength training over concentric power (CON), eccentric power (ECC), ECC/CON ratio, and 20 m linear sprint performance in elite young soccer players. Twenty young elite Spanish soccer players were assigned to an experimental group (CPG) which performed a front-step exercise using a conical pulley, 2–3 sets of 6 repetitions each leg, during 9 weeks (CPG, n=10) in addition to its usual strength training, or to a control group (CG, n=10). The improvements in the ECC mean power (36%, ES=1.61), and ECC / CON ratio (17%, ES=1.77) were substantially greater in the CPG than in the CG while the CON mean power (16%, ES=0.83) was substantially greater in the CG than in the CPG. The sprinting time for 10 m (2.8%, ES=0.78) and the 10 m flying time between 10–20 m (1.72%, ES=0.41) were substantially enhanced in CPG and CG respectively. To be efficient when defining a functional strength training and performance increments using an inertial device, the mean power output need to be measured during the CON and ECC phases and an analysis of the ECC / CON ratio should be included.
Cobalt Used as a Novel and Reusable Catalyst: A New and One-Pot Synthesis of Isatin-Derived N,S-Acetals Using Substituted Isatins and Thiols
Authors: da Silva Caren D. G. , Katla Ramesh , dos Santos Beatriz F. , Tavares Junior José M. C. , Albuquerque Tábata B. , Kupfer Vicente L. , Rinaldi Andrelson W. , Domingues Nelson L. C.
Published: August 2019

The synthesis of isatin-derived N,S-acetals using cobalt as a recyclable heterogeneous catalyst in batch and continuous flow is reported for the first time. The present protocol produced high yields, which can be observed from the reaction between ketimines and thiols. Such reactions can also be applied to a gram-scale. In addition, the catalyst is recyclable, economically-viable, and nontoxic as well as easy to prepare. The remarkable features of this new methodology are high conversion and cleaner reaction profiles.
Preparation of the Serotonin Transporter PET Radiotracer 2-({2-[(Dimethylamino)methyl]phenyl}thio)-5-[18F]fluoroaniline (4-[18F]ADAM): Probing Synthetic and Radiosynthetic Methods
Authors: Milicevic Sephton Selena , Zhou Xiaoyun , Thompson Stephen , Aigbirhio Franklin I.
Published: August 2019

Serotonin transporters (SERTs) are involved in regulating the concentration of synaptic serotonin and present a good target for many neurologic and psychiatric disorder drugs. Positron-emission tomography (PET) is a valuable tool in both diagnosis and monitoring treatment therapies, and hence much effort is being given to developing suitable PET agents for imaging SERT. Our interest in applying the fluorine-18 analogue 4-[18F]ADAM for imaging SERT prompted the development of an improved synthetic route to access unlabelled ADAM. This is achieved using Pd-catalysed coupling with thiosalicylic acid and an EDC/HOBt amide coupling in 36% yield over 4 steps. A novel radiolabelling precursor, the pinacol-derived boronic ester, is prepared from the bromide using the Miyaura borylation and is obtained in 27% yield over 6 steps. Pinacolate is then used for the radiolabelling of 4-[18F]ADAM based on Cu-mediated nucleophilic fluorination in which the presence of oxygen is critical for the reaction. A 1:1 substrate to copper ratio is found to be optimal when the reaction is performed in dimethylacetamide at 85 °C. Using these conditions, 4-[18F]ADAM is prepared in 29 ± 10% (n = 6) radiochemical conversion after hydrolysis of the Boc group with HCl. Furthermore, the method is successfully automated to afford 4-[18F]ADAM in 10% radiochemical conversion.
Fragmented QRS and QRS Duration As a Marker of Myocardial Reperfusion Measured by Myocardial Blush Grade in Reperfusion Therapy: Systematic Review and Meta-Analysis
Authors: Pranata Raymond , Yonas Emir , Chintya Veresa , Alkatiri Amir Aziz
Published: August 2019

Myocardial blush grade (MBG) is an indicator of microvascular perfusion and patency and an independent predictor of cardiac outcomes. QRS duration and fragmented QRS (fQRS) before reperfusion and its changes after reperfusion are shown to be associated with MBG. We aimed to assess the latest evidence on the association between fQRS and QRS duration with MBG in reperfusion therapy.

We performed a comprehensive search on the association between fQRS and QRS duration in successful/impaired reperfusion measured by MBG.

There were a total of 1,311 patients from six studies. A shorter QRS duration immediately and at 60 minutes after reperfusion attempt was associated with successful reperfusion, with a mean difference (MD) of –10.62 ms ([–15.55, –5.70]; p < 0.001; I
2 = 69%) and –15.66 ms ([–19.96, –11.37]; p < 0.001; I
2 = 77%), respectively, and upon sensitivity analysis, with exclusion of a study, heterogeneity decreases to 33 and 0%. QRS narrowing immediately and 60 minutes after reperfusion attempt was correlated with reperfusion, with an MD of –10.72 ([–16.57, –4.88] ; p < 0.001; I
2 = 97%) and –10.93 ([–14.00, –7.85]; p < 0.001; I
2 = 97%), lesser in impaired reperfusion, respectively. QRS duration on admission was not associated with reperfusion outcome. Two studies reported that fQRS was associated with impaired perfusion, with an odds ratio of 9.88 ([5.62–17.38]; p < 0.0001) and 4.74 ([2.45–9.20]; p < 0.0001), respectively.

A longer QRS duration immediately and at 60 minutes after reperfusion attempt was associated with impaired perfusion. QRS narrowing after reperfusion attempt was correlated with successful reperfusion. fQRS was also associated with a higher probability of impaired perfusion.
Kinematically Aligned TKA Aligns the Ankle Joint Line Closer to Those of the Native Ankle than Mechanically Aligned TKA in Bipedal Stance
Authors: Kim Jung-Taek , Han Jun , Lim Sumin , Shen Quan Hu , Won Ye Yeon
Published: August 2019

Mechanically aligned total knee arthroplasty (MATKA) aims to make alignment of the hip, knee, and ankle straight unexceptionally. However, emerging evidence suggests that unexceptional straightening the mechanical axis of the lower limb may lead to clinical and radiological problems of the ankle joint. By contrast, kinematically aligned total knee arthroplasty (KATKA) strives to restore the articular surface of the prearthritic knee. In this study, we examined results from KATKA and MATKA to determine which surgery restores the ankle joint orientation closer to the native ankle joint in bipedal stance and hypothesized that KATKA, rather than MATKA, would be more effective. Data from long-leg standing radiographs of 60 healthy adults (control group, n = 120 knees), patients who underwent MATKA (n = 90 knees), and patients who underwent KATKA (n = 90 knees) were retrospectively reviewed. The hip–knee–ankle angle, orientation of the tibial plafond and the talar dome relative to the ground (G-plafond and G-talus, respectively), and orientation of the plafond relative to the mechanical axis of the limb (M-plafond and M-talus, respectively) were measured and analyzed for comparison. Results show that bipedal stance alignment in patients who underwent KATKA (G-plafond: −0.65 ± 3.03 and G-talus: −1.72 ± 4.02) were not significantly different to native ankle joint alignment indicated by the control group. Compared with the native ankle joint measured in the control group (G-plafond: −0.76 ± 2.69 and G-talus: −1.30 ± 3.25), the tibial plafond and talar dome significantly tilted laterally relative to the ground in ankle joints after MATKA (G-plafond: −2.32 ± 3.30 and G-talus: −2.97 ± 3.98, p = 0.001 and p = 0.004, respectively). Thus, postoperative ankle joint line orientation after KATKA was horizontal to the floor and closer to that of native ankle joints than those after MATKA. The level of evidence is Level III.
Patch Test Results and Outcome in Patients with Complications from Total Knee Arthroplasty: A Consecutive Case Series
Authors: Sasseville Denis , Alfalah Khuzama , Savin Evgeny
Published: August 2019

The role of hypersensitivity in implant-related complications remains controversial. The objectives of our study were to (1) establish the prevalence of hypersensitivity to components of knee prostheses in patients referred to our contact dermatitis clinic, (2) determine if patients with post-surgery dermatitis have become sensitized, and (3) describe the outcome of patients with and without hypersensitivity. We reviewed the charts of patients referred from 2007 to 2018 and extracted demographic information, date, type, and site of implant, clinical presentation, and results of patch testing (PT) or lymphocyte transformation tests (LTT). We called most patients to gather data such as clinical outcome, nature, and timing of additional surgery. Statistical analysis included computation of conventional descriptive statistics. Because of the type of study design, only some categorical variables were tested for possible associations by analytical tools (cross-tabulation). Thirty-nine patients, 23 men (59.0%), and 16 women (41.0%), were included. Their mean age in years was 63.3 (95% confidence interval [CI]: 60.9–65.7) ranging from 39.0 to 79.0, (standard deviation) = 9.69, without statistically significant differences between males and females. Five patients had positive PT possibly relevant to their implant. Four patients had revision surgery and two improved. Of nine patients with dermatitis, one with relevant PT did not improve after revision, and the dermatitis was unrelated to TKA in eight. Of the 26 patients without dermatitis or relevant PT results, 9 had revisions because of incapacitating symptoms, and 5 improved. Hypersensitivity to implant components is a potential factor in the etiology of TKA complications. Patients with confirmed hypersensitivity may benefit from revision. Our study, however, did not detect statistically significant differences in outcome of revision surgery between patients with positive versus negative PT or LTT. In spite of this, we consider that patients with a history suggestive of metal, acrylate or aminoglycoside allergy should be tested preoperatively to avoid hypersensitivity-related postoperative complications. In the absence of hypersensitivity, some patients with incapacitating symptoms may also improve following revision.
Evaluation of Knee Cartilage Diurnal, Activity, and BMI-Related Variations Using Quantitative T2 Mapping MRI and Fitbit Activity Tracking
Authors: Matcuk George R. , Jones Ian A. , McIntyre J. Alex , Burt Robert , Hwang Darryl , Cen Steven , Schein Aaron J. , Vangsness C. Thomas
Published: August 2019

The aim of this study is to evaluate diurnal variation in knee cartilage 3 Tesla magnetic resonance imaging (MRI) T2 mapping relaxation times, as well as activity- and body mass index (BMI)-dependent variability, using quantitative analysis of T2 values from segmented regions of the weight-bearing articular surfaces of the medial and lateral femoral condyles and tibial plateaus. Ten healthy volunteers' daily activity (steps) were tracked with Fitbit pedometers. Sagittal MRI T2 maps were obtained in the morning and afternoon on days 2 and 3. Mean T2 values were analyzed for variation related to the number of steps taken (activity), time of day (diurnal variation), and BMI using mixed effect model. Significant (albeit small) differences in the medial femoral and medial tibial cartilage regions were identified between morning and afternoon scans (diurnal variation). Daily activity did not result in significant changes and increasing BMI only demonstrated a slight increase in T2 values for the lateral tibial plateau. These findings suggest that it may be necessary to control diurnal variation when using quantitative MRI T2 mapping to assess articular cartilage longitudinally in healthy participants. Further investigation is needed to confirm these findings and determine if they also apply to symptomatic patients.
Osmotic pressure of permeable ionic microgels: Poisson-Boltzmann theory and exact statistical mechanical relations in the cell model
Authors: Denton Alan R. , Alziyadi Mohammed O.
Published: August 2019

Ionic microgels are soft colloidal particles, composed of crosslinked polymer networks, which ionize and swell when dispersed in a good solvent. Swelling of these permeable, compressible particles involves a balance of electrostatic, elastic, and mixing contributions to the single-particle osmotic pressure. The electrostatic contribution depends on the distributions of mobile counterions and coions and of fixed charge on the polymers. Within the cell model, we employ two complementary methods to derive the electrostatic osmotic pressure of ionic microgels. In Poisson-Boltzmann (PB) theory, we minimize a free energy functional with respect to the electrostatic potential to obtain the bulk pressure. From the pressure tensor, we extract the electrostatic and gel contributions to the total pressure. In a statistical mechanical approach, we vary the free energy with respect to microgel size to obtain exact relations for the microgel electrostatic osmotic pressure. We present results for planar, cylindrical, and spherical geometries. For models of membranes and microgels with fixed charge uniformly distributed over their surface or volume, we derive analogs of the contact value theorem for charged colloids. We validate these relations by solving the PB equation and computing ion densities and osmotic pressures. When implemented within PB theory, the two methods yield identical electrostatic osmotic pressures for surface-charged microgels. For volume-charged microgels, the exact electrostatic osmotic pressure equals the average of the corresponding PB profile over the gel volume. We demonstrate that swelling of ionic microgels depends on the variation of the electrostatic pressure inside the particle and discuss implications for interpreting experiments.
Polarization states synthesizer based on a thermo-optic dielectric metasurface
Authors: Bosch M. , Shcherbakov M. R. , Fan Z. , Shvets G.
Published: August 2019

A tunable polarization state converter/synthesizer based on an anisotropic resonant metasurface (ARM) is demonstrated. The semiconductor-based metasurface is designed to have a thermo-optically actuated optical mode excited by an incident free-space optical field. A diversity of output polarization states is reversibly generated and controlled by the temperature-dependent phase retardance between the two principal linear polarization states. The effect of metasurface inhomogeneity on the range of achievable polarization states is discussed and quantified, and the potential routes to “perfect” efficiency are suggested. By virtue of having a thickness of a fraction of the operating wavelength, ARMs represent a novel class of tunable polarization states’ generating devices poised to find use in free-space communications and other applications.
Vibrational response of Au-Ag alloy and porous Au single nanowires probed by ultrafast pump-probe spectroscopy
Authors: Delalande R. , Burr L. , Charron E. , Jouini M. , Toimil-Molares M. E. , Belliard L.
Published: August 2019

We report on the ultrafast vibrational response of single Au-Ag alloy and Au porous nanowires obtained by the template method. The oscillations of the sample reflectivity are correlated with eigenmodes (EM) confined in the nanowire. Taking advantage of a free standing geometry, we are able to detect few harmonics. Coupling electron microscopy and pump-probe investigations with a very high spectral resolution performed on the same wire, we demonstrate that both longitudinal and transverse sound velocities could be obtained for variable Au concentrations. An additional quadrupolar mode is also observed and reproduced by finite element simulation. Finally, porous nanowires are investigated.
Investigation of the nanochannel geometry modulation on self-heating in AlGaN/GaN Fin-HEMTs on Si
Authors: Wu Mei , Ma Xiao-Hua , Yang Ling , Zhang Meng , Zhu Qing , Zhang Xin-Chuang , Hou Bin , Zheng Xue-Feng , Hao Yue
Published: August 2019

The impact of the nanochannel geometry on the thermal performance of AlGaN/GaN Fin-HEMTs was investigated. Structures with a larger nanochannel space (Sfin) or a smaller nanochannel width (Wfin) show the suppressed self-heating effect, which was confirmed by the smaller dispersion between DC and pulsed measurements together with the reduced high temperature degradation of the drain current. A closed-form expression based on the heat flow theory was used to illustrate the coupling effect of Wfin and Sfin, and the channel temperature was mapped considering the different nanochannel geometries. As Wfin and Sfin scale down simultaneously, the nanochannel structure would present a much lower channel temperature, demonstrating that the heat generation dominated by Wfin has a greater impact on the self-heating in Fin-HEMTs.
Substantially enhanced ferroelectricity in JT ion Cu2+-doped Co1–xCuxCr2O4 (0≤x≤0.4)
Authors: Wang D. , Shu M. F. , Yin L. H. , Tang X. W. , Tong P. , Zhu X. B. , Yang J. , Song W. H. , Sun Y. P.
Published: August 2019

We investigate the effect of Jahn-Teller (JT) active Cu2+ ions on the structural, magnetic, and ferroelectric properties of Co1–xCuxCr2O4 (0 ≤x≤ 0.4). All the samples can be indexed with a cubic lattice with space group Fd3¯m at room temperature. All the samples undergo a paramagnetic-ferrimagnetic transition at TC and spiral ferrimagnetic ordering at TS. The magnetization measurements manifest that magnetization reversal occurs in the x = 0.2 and 0.3 samples. The x = 0.3 sample possesses a rather large polarization of 14 μC/m2, which is 7 times in magnitude compared with the CoCr2O4 single crystal. The analysis of the infrared active phonon modes implies that two T1u(IR) optical phonon modes are gradually split into a doublet at around 40 K, implying the lowering of lattice symmetry. The presence of a low-symmetry tetragonal phase becomes polar and enhances the electric polarization of Co0.7Cu0.3Cr2O4.
Ultra-wide-bandgap AlGaN homojunction tunnel diodes with negative differential resistance
Authors: Clinton Evan A. , Engel Zachary , Vadiee Ehsan , Carpenter Joe V. , Holman Zachary C. , Doolittle W. Alan
Published: August 2019

The power efficiencies of state-of-the-art AlxGa1-xN deep-ultraviolet (UV) emitters operating in the <300 nm wavelength region are currently limited to a few percent in part due to limitations in the series and contact resistance which result in excessive drive voltages. AlxGa1-xN tunnel contacts and tunnel junctions in deep-UV devices are a promising route toward increasing these efficiencies by improving the contact resistances, hole injection, and reducing optical absorption by removing undesirable p-GaN contact layers. However, due to doping inefficiencies, standalone tunnel diodes have not been realized in the form of homojunction AlxGa1-xN. In this work, AlxGa1-xN (0.19 ≤ x ≤ 0.58) homojunction tunnel diodes are fabricated with high reverse bias current densities, and one device with x = 0.19 demonstrates a negative differential resistance at ∼2.4 V. AlxGa1-xN p++/n++/n tunnel diodes are compared to reference p++/i/n diodes to provide clarity about the role of tunneling conduction vs leakage conduction. Transmission electron microscopy verifies that heavy doping does not result in visible defects such as Mg precipitates and allows for subsequent epitaxy, critical for buried tunnel junction structures. Increasing the bandgap energy of AlxGa1-xN for higher Al content tunnel junctions decreases the tunnel current, but still allows sufficient conduction necessary for future improvements in deep UV emitter efficiencies.
The effect of luminescent coupling on modulated photocurrent measurements in multijunction solar cells
Authors: Márquez Peraca Nicolás , Haney Paul M. , Hamadani Behrang H.
Published: August 2019

Luminescent coupling in multijunction solar cells has a major impact on device response, and its impact on current-voltage and quantum efficiency measurements is well established. However, the role of luminescent coupling in more advanced characterization techniques such as modulated photocurrent spectroscopy is virtually unknown. Here, we present measurements of the frequency-dependent photocurrent of a triple junction solar cell with significant coupling between adjacent junctions. We develop an equivalent circuit model that includes luminescent coupling which shows good agreement with the measured frequency response. The model also shows how the system response can elucidate the type of charge carrier recombination in these III-V semiconductor materials.
Design of metal contacts for monolayer Fe3GeTe2 based devices
Authors: Wu Qingyun , Ang Yee Sin , Cao Liemao , Ang Lay Kee
Published: August 2019

Using ab initio density functional calculations, we study the interfacial properties of the Fe3GeTe2 monolayer in contact with the Au, Cu, In, Cr, Ti, and Ni metal substrates. It is found that Cr, Ti, and Ni bind strongly with Fe3GeTe2, in contrast to Au, Cu, and In. By analyzing the density of states, charge redistribution, and tunneling barrier, it is suggested that the commonly used Au, Cu, In, and Cr electrodes are insufficient for the electron and spin injection. Ti and Ni metal substrates are proposed to have good electronic transparency to the Fe3GeTe2 monolayer. The Ni substrate is found to have a large spin injection to the Fe3GeTe2 monolayer in addition to its excellent electron injection. Our results indicate that Ni is a promising electrode for the Fe3GeTe2 monolayer to form current in-plane devices, thus shedding light on the optimal selection of metal electrodes for the development of next generation spintronic devices based on atomically thin nanomaterials.
IL-2 production by self-reactive CD4 thymocytes scales regulatory T cell generation in the thymus
Authors: Hemmers Saskia , Schizas Michail , Azizi Elham , Dikiy Stanislav , Zhong Yi , Feng Yongqiang , Altan-Bonnet Grégoire , Rudensky Alexander Y.
Published: August 2019

Regulatory T (T reg) cells, a specialized subset of CD4+ T cells, are essential to prevent fatal autoimmunity. Expression of the T reg lineage-defining transcription factor Foxp3, and therefore their differentiation in the thymus, is dependent upon T cell receptor (TCR) and interleukin-2 (IL-2) signaling. Here, we report that the majority of IL-2–producing cells in the thymus are mature CD4 single-positive (CD4SP) thymocytes and that continuous IL-2 production sustained thymic T reg cell generation and control of systemic immune activation. Furthermore, single-cell RNA sequencing analysis of CD4 thymocyte subsets revealed that IL-2 was expressed in self-reactive CD4SP thymocytes, which also contain T reg precursor cells. Thus, our results suggest that the thymic T reg cell pool size is scaled by a key niche factor, IL-2, produced by self-reactive CD4SP thymocytes. This IL-2–dependent scaling of thymic T reg cell generation by overall self-reactivity of a mature post-selection thymic precursor pool may likely ensure adequate control of autoimmunity.
Methodology to evaluate the placement of wind turbine based on GIS technology
Authors: Vaysman Ya I , Surkov A A , Surkova Yu I , Vlasov A S , Kychkin A V
Published: August 2019

The paper is devoted to the development of a methodology to evaluate the possible locations of wind generators using GIS technologies for the climatic conditions of the Western Urals. A model of the wind generator operation in the electrical network using the OpenModelica simulation environment has been built. Recommendations on the use of a wind generator and a feasibility study of its use on the base of an energy-efficient autonomous research module (EEARM) are worked out.
Human capital for sustainable development: a comparative analysis of regions of the Republic of Kazakhstan
Authors: Panzabekova A , Satybaldin A , Alibekova G , Abilkayir N
Published: August 2019

Human capital is the primary base for sustainable development at both macro, middle, and micro levels. The purpose of this study is the preliminary clustering of the regions of Kazakhstan according to human capital factors as public health and environmental issues. The results are intermediate and are subject to further study.
Probing DNA nucleobases with diamond (111) surfaces
Authors: Putra Miftahussurur Hamidi , Fyta Maria
Published: August 2019

DNA units, the nucleobases, are probed with diamond (111) surfaces. The nucleobases are placed on top of a diamond surface interacting in a very specific way with the surface atoms. Different elements, such as hydrogen, nitrogen, and fluorine are chosen for the termination of the diamond. The energetic features and electronic properties of the combined system ’nucleobase/diamond surface’ are thoroughly studied using quantum-mechanical calculations. These point to nucleobase- and termination-specific characteristics linking to the potential of using diamond surfaces for identifying the DNA nucleobases. Focus is further given on mixed surfaces with a varying nitrogen and hydrogen coverage. For these, we provide pathways for tuning the electronic band gap of the surface/nucleobase complex with the nitrogen content of the surface. The results could unravel a clear crossover in the surface electron affinity and its relation to a reversal in the positions of the electronic band extremes from the material to the molecule and vice versa. These features link to a further selective modulation of the electronic transport and the excitation properties of the complexes with a strong biosensing potential.
The effects of charge density distributions of metal ions on single water molecule dissociation of [M(H2O)6]3+ systems
Authors: Kuncoro Handoko Setyo , Sakaue Mamoru , Kasai Hideaki
Published: August 2019

Some effects of cationic charge density distribution on single water molecule dissociation of [M(H2O)6]3+ clusters with M=Cr, Mn, Fe, Co, and Ni have been investigated using first-principles study. The molecular structures, molecular binding energies, hydration enthalpies, cation and water molecules orbitals, infrared vibrational frequencies, and potential energy surfaces/curves had been computed to fulfill the purpose of research. Our investigation results have revealed that the hollow shape of charge density of central Cr(III) makes the Cr-O bonds rigid as indicated by a higher activation energy for releasing one water molecule from [Cr(H2O)6]3+. The isotropic charge density of Fe(III) affects in lowering water rotational rigidities which is responsible for augmenting the activation energy, while the cones-shape charge density of Ni(III) weakens the ion-dipole interactions by increasing interactions between nearest neighbour water molecules.
The unified soliton system as the AdS2 system
Authors: Hayashi Masahito , Shigemoto Kazuyasu , Tsukioka Takuya
Published: August 2019

We study the Riemann geometric approach to be aimed at unifying soliton systems. The general two-dimensional Einstein equation with a constant negative scalar curvature becomes an integrable differential equation. We show that such Einstein equation includes KdV/mKdV/sine-Gordon equations.
Size, Shape, and Distribution of Multivesicular Bodies in the Juvenile Rat Somatosensory Cortex: A 3D Electron Microscopy Study
Authors: Turegano-Lopez M , Santuy A , DeFelipe J , Merchan-Perez A
Published: August 2019

Multivesicular bodies (MVBs) are membrane-bound organelles that belong to the endosomal pathway. They participate in the transport, sorting, storage, recycling, degradation, and release of multiple substances. They interchange cargo with other organelles and participate in their renovation and degradation. We have used focused ion beam milling and scanning electron microscopy (FIB-SEM) to obtain stacks of serial sections from the neuropil of the somatosensory cortex of the juvenile rat. Using dedicated software, we have 3D-reconstructed 1618 MVBs. The mean density of MVBs was 0.21 per cubic micron. They were unequally distributed between dendrites (39.14%), axons (18.16%), and nonsynaptic cell processes (42.70%). About one out of five MVBs (18.16%) were docked on mitochondria, representing the process by which the endosomal pathway participates in mitochondrial maintenance. Other features of MVBs, such as the presence of tubular protrusions (6.66%) or clathrin coats (19.74%) can also be interpreted in functional terms, since both are typical of early endosomes. The sizes of MVBs follow a lognormal distribution, with differences across cortical layers and cellular compartments. The mean volume of dendritic MVBs is more than twice as large as the volume of axonic MVBs. In layer I, they are smaller, on average, than in the other layers.
The application of geographic information systems (ArcGIS) in selecting locations for installing banners and billboards in a health campaign
Authors: Sadeghi Reza , Mazloomy-Mahmoodabad Seyed-Saeed , Rezaeian Mohsen , Fallahzadeh Hossein , Khanjani Narges
Published: August 2019

In recent years, the geographic information system (GIS) application has used the latest spatial data to help researchers make the right decisions in the shortest time. This study was conducted with the aim of using geographic information systems (ArcGIS) for selecting the best location for installing banners and billboards in a health campaign. This research was an analytical and applied research conducted in Sirjan city, Iran in 2018. In this research, GIS and fuzzy logic methods were used. In order to implement the fuzzy operator in the GIS environment, initially, the main influencing criteria in location selection were determined. Then the weighted layers were put on top of each other and, by considering the sub criteria, the most suitable places to install banners and billboards were identified in the final map. The final map showed the best places to install billboards and educational banners for the ‘hookah is the enemy of health’ campaign. The final number of these places was 30 according to the main criteria, and the number was reduced to 25 places, after considering the sub criteria. ArcGIS can be used in selecting the best locations for installing banners and billboards in a health campaign.
Evidence That Blunted CD4 T-Cell Responses Underlie Deficient Protective Antibody Responses to Influenza Vaccines in Repeatedly Vaccinated Human Subjects
Authors: Richards Katherine A , Shannon Ian , Treanor John J , Yang Hongmei , Nayak Jennifer L , Sant Andrea J
Published: August 2019

Despite the benefits of yearly influenza vaccination, accumulating evidence suggests that diminished vaccine efficacy may be related to repeated vaccination. Although studied at the level of B-cell responses, CD4 T-cell responses have not yet been examined. In this study, we analyze CD4 T-cell responses to influenza vaccination in subjects who differ in their vaccine history. We find a striking disparity in their responses, with previously vaccinated subjects exhibiting significantly blunted CD4 T-cell responses and diminished antibody responses. These results suggest that limiting CD4 T-cell help mteaserrlie the diminished or altered antibody responses in repeatedly vaccinated subjects.
Efficacy of Active Immunization With Attenuated α-Hemolysin and Panton-Valentine Leukocidin in a Rabbit Model of Staphylococcus aureus Necrotizing Pneumonia
Authors: Tran Vuvi G , Venkatasubramaniam Arundhathi , Adhikari Rajan P , Krishnan Subramaniam , Wang Xing , Le Vien T M , Le Hoan N , Vu Trang T T , Schneider-Smith Erika , Aman M Javad , Diep Binh An
Published: August 2019

Staphylococcus aureus is a common pathogen causing infections in humans with various degrees of severity, with pneumonia being one of the most severe infections. In as much as staphylococcal pneumonia is a disease driven in large part by α-hemolysin (Hla) and Panton-Valentine leukocidin (PVL), we evaluated whether active immunization with attenuated forms of Hla (HlaH35L/H48L) alone, PVL components (LukS-PVT28F/K97A/S209A and LukF-PVK102A) alone, or combination of all 3 toxoids could prevent lethal challenge in a rabbit model of necrotizing pneumonia caused by the USA300 community-associated methicillin-resistant S. aureus (MRSA). Rabbits vaccinated with Hla toxoid alone or PVL components alone were only partially protected against lethal pneumonia, whereas those vaccinated with all 3 toxoids had 100% protection against lethality. Vaccine-mediated protection correlated with induction of polyclonal antibody response that neutralized not only α-hemolysin and PVL, but also other related toxins, produced by USA300 and other epidemic MRSA clones.
Inside the Open Source Community
Authors: Kunkel Julian
Published: August 2019

Julian Kunkel from the BCS Open Source SG explains why collaboratively created software development is so popular, how its economics work and how contributing to a project is easier than you think.
Challenging current interpretation of sunflower movements
Authors: van Wyk Anne S , Prinsloo Gerhard
Published: August 2019

Several misconceptions may exist in the literature regarding Helianthus annuus L. (sunflower) movements due to the exclusion of the earth’s rotation around its own axis, gravity, and gravitation.
ABC transporter OsABCG18 controls the shootward transport of cytokinins and grain yield in rice
Authors: Zhao Jiangzhe , Yu Ningning , Ju Min , Fan Biao , Zhang Yanjun , Zhu Engao , Zhang Mengyuan , Zhang Kewei
Published: August 2019

Cytokinins are one of the most important phytohormones and play essential roles in multiple life processes in planta. Root-derived cytokinins are transported to the shoots via long-distance transport. The mechanisms of long-distance transport of root-derived cytokinins remain to be demonstrated. In this study, we report that OsABCG18, a half-size ATP-binding cassette transporter from rice (Oryza sativa L.), is essential for the long-distance transport of root-derived cytokinins. OsABCG18 encodes a plasma membrane protein and is primarily expressed in the vascular tissues of the root, stem, and leaf midribs. Cytokinin profiling, as well as [14C]trans-zeatin tracer, and xylem sap assays, demonstrated that the shootward transport of root-derived cytokinins was significantly suppressed in the osabcg18 mutants. Transport assays in tobacco (Nicotiana benthamiana) indicated that OsABCG18 exhibited efflux transport activities for various substrates of cytokinins. While the mutation reduced root-derived cytokinins in the shoot and grain yield, overexpression of OsABCG18 significantly increased cytokinins in the shoot and improved grain yield. The findings for OsABCG18 as a transporter for long-distance transport of cytokinin provide new insights into the cytokinin transport mechanism and a novel strategy to increase cytokinins in the shoot and promote grain yield.
Asteroseismology of tidally distorted sdB stars
Authors: Preece Holly P , Jeffery C Simon , Tout Christopher A
Published: August 2019

Most subdwarf B stars are located in post-common envelope binaries. Many are in short-period systems subject to tidal influence, and many show pulsations useful for asteroseismic inference. In combination, one must quantify when and how tidal distortion affects the normal modes. We present a method for computing tidal distortion and associated frequency shifts. Validation is by application to polytropes and comparison with previous work. For typical sdB stars, a tidal distortion to the radius of between $0.2\,$ and $2\,$ per cent is generated for orbital periods of 0.1 d. Application to numerical helium core-burning stars identifies the period and mass-ratio domain where tidal frequency shifts become significant and quantifies those shifts in terms of binary properties and pulsation modes. Tidal shifts disrupt the symmetric form of rotationally split multiplets by introducing an asymmetric offset to modes. Tides do not affect the total spread of a rotationally split mode unless the stars are rotating sufficiently slowly that the rotational splitting is smaller than the tidal splitting.
The case of NGC 6302: the impact of shocks in the derivation of nitrogen abundances
Authors: Lago P J A , Costa R D D , Faúndez-Abans M , Maciel W J
Published: August 2019

High nitrogen abundance is characteristic of Type I planetary nebulae, as well as their highly filamentary structure. In the present work, we test the hypothesis of shocks as a relevant excitation mechanism for a Type I nebula, NGC 6302, using recently released diagnostic diagrams to distinguish shocks from photoexcitation. The construction of the diagrams depends on emission-line ratios and kinematical information. NGC 6302 shows the relevance of shocks in peripheral regions and their importance to the whole nebula. Using shocks, we question the usual assumption of ionization correction factor calculation, justifying a warning regarding broadly used abundance derivation methods. From kinematical analysis, we derive a new distance for NGC 6302 of $805\pm 143\,$ pc.
Stellar bars in counter-rotating dark matter haloes: the role of halo orbit reversals
Authors: Collier Angela , Shlosman Isaac , Heller Clayton
Published: August 2019

Disc galaxies can exchange angular momentum and baryons with their host dark matter (DM) haloes. These haloes possess internal spin, λ, which is insignificant rotationally but does affect interactions between the baryonic and DM components. While statistics of prograde and retrograde spinning haloes in galaxies is not available at present, the existence of such haloes is important for galaxy evolution. In the previous works, we analysed dynamical and secular evolution of stellar bars in prograde spinning haloes and the DM response to the bar perturbation, and found that it is modified by the resonant interactions between the bar and the DM halo orbits. In this work, we follow the evolution of stellar bars in retrograde haloes. We find that this evolution differs substantially from evolution in rigid unresponsive haloes, discussed in the literature. First, we confirm that the bar instability is delayed progressively along the retrograde λ sequence. Secondly, the bar evolution in the retrograde haloes differs also from that in the prograde haloes, in that the bars continue to grow substantially over the simulation time of 10 Gyr. The DM response is also substantially weaker compared to this response in the prograde haloes. Thirdly, using orbital spectral analysis of the DM orbital structure, we find a phenomenon we call the orbit reversal – when retrograde DM orbits interact with the stellar bar, reverse their streaming and precession, and become prograde. This process dominates the inner halo region adjacent to the bar and allows these orbits to be trapped by the bar, thus increasing efficiency of angular momentum transfer by the inner Lindblad resonance. We demonstrate this reversal process explicitly in a number of examples.
Evolution of neutral oxygen during the epoch of reionization and its use in estimating the neutral hydrogen fraction
Authors: Doughty Caitlin , Finlator Kristian
Published: August 2019

We use synthetic sightlines drawn through snapshots of the Technicolour Dawn simulations to explore how the statistics of neutral oxygen (${\mathrm{O}\,{\small I}}$) absorbers respond to hydrogen reionization. The ionization state of the circumgalactic medium (CGM) initially roughly tracks that of the intergalactic medium, but beginning at z = 8 the CGM grows systematically more neutral owing to self-shielding. Weak absorbers trace diffuse gas that lies farther from haloes, hence they are ionized first, whereas stronger systems are less sensitive to reionization. The overall ${\mathrm{O}\,{\small I}}$ covering fraction decreases slowly with time owing to competition between ongoing enrichment and gradual encroachment of ionization fronts into increasingly overdense gas. While the declining covering fraction is partially offset by continued formation of new haloes, the ionization of the diffuse gas causes the predicted line-of-sight incidence rate of ${\mathrm{O}\,{\small I}}$ absorbers to decline abruptly at the overlap epoch, in qualitative agreement with observations. In comparison to the recently observed equivalent width (EW) distribution at z ≈ 6, the simulations underproduce systems with $\mathrm{EW} \ge 0.1 \mathring{\rm A}$, although they reproduce weaker systems with $\mathrm{EW} \ge 0.05 \mathring{\rm A}$. By z ≈ 5, the incidence of $\mathrm{EW} \lt 0.1 \mathring{\rm A}$ systems are overproduced, consistent with previous indications that the simulated ionizing background is too weak at z < 6. The summed column densities of $\mathrm{Si}\,{\small II}$ and $\mathrm{Si}\,{\small IV}$ trace the total oxygen column, and hence the ratio of the ${\mathrm{O}\,{\small I}}$ and $\mathrm{Si}\,{\small II}+ \mathrm{Si}\,{\small IV}$ comoving mass densities traces the progress of reionization. This probe may prove particularly useful in the regime where $x_{\mathrm{H}\,{\small I}} \gt 10{{\ \rm per\ cent}}$.