bluuebunny/crossref_metadata_2025 huggingface dataset:
Pediatric Integrative Medicine in Residency Program: Relationship between Lifestyle Behaviors and Burnout and Wellbeing Measures in First-Year Residents
Authors: McClafferty Hilary , Brooks Audrey J. , Chen Mei-Kuang , Brenner Michelle , Brown Melanie , Esparham Anna , Gerstbacher Dana , Golianu Brenda , Mark John , Weydert Joy , Yeh Ann Ming , Maizes Victoria
Published: April 2018

It is widely recognized that burnout is prevalent in medical culture and begins early in training. Studies show pediatricians and pediatric trainees experience burnout rates comparable to other specialties. Newly developed Accreditation Council for Graduate Medical Education (ACGME) core competencies in professionalism and personal development recognize the unacceptably high resident burnout rates and present an important opportunity for programs to improve residents experience throughout training. These competencies encourage healthy lifestyle practices and cultivation of self-awareness, self-regulation, empathy, mindfulness, and compassion—a paradigm shift from traditional medical training underpinned by a culture of unrealistic endurance and self-sacrifice. To date, few successful and sustainable programs in resident burnout prevention and wellness promotion have been described. The University of Arizona Center for Integrative Medicine Pediatric Integrative Medicine in Residency (PIMR) curriculum, developed in 2011, was designed in part to help pediatric programs meet new resident wellbeing requirements. The purpose of this paper is to detail levels of lifestyle behaviors, burnout, and wellbeing for the PIMR program’s first-year residents (N = 203), and to examine the impact of lifestyle behaviors on burnout and wellbeing. The potential of the PIMR to provide interventions addressing gaps in lifestyle behaviors with recognized association to burnout is discussed.
Suppression of Quantum-Mechanical Collapse in Bosonic Gases with Intrinsic Repulsion: A Brief Review
Authors: Malomed Boris A.
Published: April 2018

It is known that attractive potential ~− 1 / r 2 gives rise to the critical quantum collapse in the framework of the three-dimensional (3D) linear Schrödinger equation. This article summarizes theoretical analysis, chiefly published in several original papers, which demonstrates suppression of the collapse caused by this potential, and the creation of the otherwise missing ground state in a 3D gas of bosonic dipoles pulled by the same potential to the central charge, with repulsive contact interactions between them, represented by the cubic term in the respective Gross–Pitaevskii equation (GPE). In two dimensions (2D), quintic self-repulsion is necessary for the suppression of the collapse; alternatively, this may be provided by the effective quartic repulsion produced by the Lee–Huang–Yang correction to the GPE. 3D states carrying angular momentum are constructed in the model with the symmetry reduced from spherical to cylindrical by an external polarizing field. Interplay of the collapse suppression and miscibility–immiscibility transition is considered in a binary condensate. The consideration of the 3D setting in the form of the many-body quantum system, with the help of the Monte Carlo method, demonstrates that, although the quantum collapse cannot be fully suppressed, the self-trapped states predicted by the GPE exist in the many-body setting as metastable modes protected against the collapse by a tall potential barrier.
Shifting the Shear Paradigm in the Crystallographic Models of Displacive Transformations in Metals and Alloys
Authors: Cayron Cyril
Published: April 2018

Deformation twinning and martensitic transformations are characterized by the collective displacements of atoms, an orientation relationship, and specific morphologies. The current crystallographic models are based on the 150-year-old concept of shear. Simple shear is a deformation mode at constant volume, relevant for deformation twinning. For martensitic transformations, a generalized version called invariant plane strain is used; it is associated with one or two simple shears in the phenomenological theory of martensitic crystallography. As simple shears would involve unrealistic stresses, dislocation/disconnection-mediated versions of the usual models have been developed over the last decades. However, a fundamental question remains unsolved: how do the atoms move? The aim of this paper is to return to a crystallographic approach introduced a few years ago; the approach is based on a hard-sphere assumption and linear algebra. The atomic trajectories, lattice distortion, and shuffling (if required) are expressed as analytical functions of a unique angular parameter; the habit planes are calculated with the simple “untilted plane” criterion; non-Schmid behaviors associated with some twinning modes are also predicted. Examples of steel and magnesium alloys are taken from recent publications. The possibilities offered in mechanics and thermodynamics are briefly discussed.
Design Optimization of Polymer Heat Exchanger for Automated Household-Scale Solar Water Pasteurizer
Authors: Denkenberger David C. , Pearce Joshua M.
Published: April 2018

A promising approach to reducing the >870,000 deaths/year globally from unsafe water is flow-through solar water pasteurization systems (SWPs). Unfortunately, demonstrated systems have high capital costs, which limits access for the poor. The most expensive component of such systems is the heat exchanger (HX). Thus, this study focuses on cost optimization of HX designs for flow-through SWPs using high-effectiveness polymer microchannel HXs. The theoretical foundation for the cost optimization of a polymer microchannel HX is provided, and outputs are plotted in order to provide guidelines for designers to perform HX optimizations. These plots are used in two case studies: (1) substitution of a coiled copper HX with polymer microchannel HX, and (2) design of a polymer microchannel HX for a 3-D printed collector that can fit in an arbitrary build volume. The results show that substitution of the polymer expanded HX reduced the overall expenditure for the system by a factor 50, which aids in making the system more economical. For the second case study, the results show how future system designers can optimize an HX for an arbitrary SWP geometry. The approach of distributed manufacturing using laser welding appears promising for HX for SWP.
The Power Law Characteristics of Stock Price Jump Intervals: An Empirical and Computational Experimental Study
Authors: Cao Hongduo , Ouyang Hui , Li Ying , Li Xiaobin , Chen Ye
Published: April 2018

For the first time, the power law characteristics of stock price jump intervals have been empirically found generally in stock markets. The classical jump-diffusion model is described as the jump-diffusion model with power law (JDMPL). An artificial stock market (ASM) is designed in which an agent’s investment strategies, risk appetite, learning ability, adaptability, and dynamic changes are considered to create a dynamically changing environment. An analysis of these data packets from the ASM simulation indicates that, with the learning mechanism, the ASM reflects the kurtosis, fat-tailed distribution characteristics commonly observed in real markets. Data packets obtained from simulating the ASM for 5010 periods are incorporated into a regression analysis. Analysis results indicate that the JDMPL effectively characterizes the stock price jumps in the market. The results also support the hypothesis that the time interval of stock price jumps is consistent with the power law and indicate that the diversity and dynamic changes of agents’ investment strategies are the reasons for the discontinuity in the changes of stock prices.
Maximum Entropy Theory of Ecology: A Reply to Harte
Authors: Favretti Marco
Published: April 2018

In a paper published in this journal, I addressed the following problem: under which conditions will two scientists, observing the same system and sharing the same initial information, reach the same probabilistic description upon the application of the Maximum Entropy inference principle (MaxEnt) independent of the probability distribution chosen to set up the MaxEnt procedure. This is a minimal objectivity requirement which is generally asked for scientific investigation. In the same paper, I applied the findings to a critical examination of the application of MaxEnt made in Harte’s Maximum Entropy Theory of Ecology (METE). Prof. Harte published a comment to my paper and this is my reply. For the sake of the reader who may be unaware of the content of the papers, I have tried to make this reply self-contained and to skip technical details. However, I invite the interested reader to consult the previously published papers.
The Use of Technology to Assist School-Aged Students with High Incidence Special Needs in Reading
Authors: Stetter Maria Earman
Published: April 2018

This paper delineates some of the ways students with high incidence special needs are currently being served with technology in the United States in K–12 to learn skills or accomplish tasks related to reading. Categories examined were read aloud tools, computer applications, traditional instructional methods that utilized technology, and online instructional environments. The categories examined in online instructional environments include the prevalence of students with special needs, how Individual Education Plan requirements, such as accommodations and modifications, are being addressed, parental participation, and concerns in the online environments. Suggestions for future work at the intersection of reading technology and teachers of students with special needs are included, as well as conclusions from the current work. Future work with teachers of students with special needs is required to help better serve their unique learning requirements.
Stand-Alone Microgrid Inverter Controller Design for Nonlinear, Unbalanced Load with Output Transformer
Authors: Lim Jae-Uk , Kim Hag-Won , Cho Kwan-Yuhl , Bae Joung-Hwan
Published: April 2018

This paper proposes a technique that compensates for unbalance and nonlinearity in microgrid inverters with power transformers operating in stand-alone mode. When a microgrid inverter is operating in stand-alone mode, providing high-quality power is very important. When an unbalanced, nonlinear load is connected, zero sequence current and negative sequence current occur, which leads to an unbalanced output voltage. This paper examines why the zero sequence component occurs differently depending on the structure of a three-phase transformer connected to the inverter output terminal, and it proposes a method for controlling the zero sequence component. It also uses a resonant controller to remove the harmonics that correspond to the negative sequence component and the nonlinear component. The proposed elements were verified by a Powersim (PSIM) simulation.
Consumption-Based Blockchain Accounting of Telecoupled Global Land Resource Debtors and Creditors
Authors: Lee Huey-Lin , Lin Yu-Pin , Petway Joy R. , Settele Josef , Lien Wan-Yu
Published: April 2018

n/a
A Review on Established and Emerging Fermentation Schemes for Microbial Production of Polyhydroxyalkanoate (PHA) Biopolyesters
Authors: Koller Martin
Published: April 2018

Polyhydroxyalkanoates (PHA) are microbial biopolyesters utilized as “green plastics”. Their production under controlled conditions resorts to bioreactors operated in different modes. Because PHA biosynthesis constitutes a multiphase process, both feeding strategy and bioreactor operation mode need smart adaptation. Traditional PHA production setups based on batch, repeated batch, fed-batch or cyclic fed-batch processes are often limited in productivity, or display insufficient controllability of polyester composition. For highly diluted substrate streams like is the case of (agro) industrial waste streams, fed-batch enhanced by cell recycling has recently been reported as a viable tool to increase volumetric productivity. As an emerging trend, continuous fermentation processes in single-, two- and multi-stage setups are reported, which bring the kinetics of both microbial growth and PHA accumulation into agreement with process engineering and allow tailoring PHA’s molecular structure. Moreover, we currently witness an increasing number of CO2-based PHA production processes using cyanobacteria; these light-driven processes resort to photobioreactors similar to those used for microalgae cultivation and can be operated both discontinuously and continuously. This development is parallel to the emerging use of methane and syngas as abundantly available gaseous substrates, which also calls for bioreactor systems with optimized gas transfer. The review sheds light on the challenges of diverse PHA production processes in different bioreactor types and operational regimes using miscellaneous microbial production strains such as extremophilic Archaea, chemoheterotrophic eubacteria and phototrophic cyanobacteria. Particular emphasis is dedicated to the limitations and promises of different bioreactor–strain combinations and to efforts devoted to upscaling these processes to industrially relevant scales.
Aerodynamics of a Wing with a Wingtip Flapper
Authors: Zhao Longfei , Shkarayev Sergey , Su Erlong
Published: April 2018

In the present study, an oscillating membrane flapper was pivotally attached to the tip of a conventional rigid wing. Stroke-averaged aerodynamic forces were measured for the range of the flapping frequency, showing significant increases in the lift coefficient and lift-to-drag ratio for the wing with a flapper. Major vortex patterns were deduced from observations of smoke-wire visualization and 2D phase-locked particle image velocimetry (PIV). The centerline of the primary vortex wanders in the counterclockwise direction. On the contrary, its core rotates in the same sense of rotation as a wingtip vortex in a conventional wing. The secondary weaker vortex of opposite rotation lasts for a half stroke. The vortex ring sheds from the flapper during the second half of the upstroke and pronation. The outer parts of the vortex system are much stronger than the inner ones. The circulation and size of vortices decrease significantly at the most distant station from the wing. Strong vertical jets were found in smoke-wire visualization and confirmed with velocity and vorticity fields obtained by PIV. These jets are formed between undulating vortices and inside of the vortex ring. The jet airflow moves away from the flapper and downward or upward depending on the flapping direction.
Topographic Effects in Geoid Determinations
Authors: Sjöberg Lars E.
Published: April 2018

Traditionally, geoid determination is applied by Stokes’ formula with gravity anomalies after removal of the attraction of the topography by a simple or refined Bouguer correction, and restoration of topography by the primary indirect topographic effect (PITE) after integration. This technique leads to an error of the order of the quasigeoid-to-geoid separation, which is mainly due to an incomplete downward continuation of gravity from the surface to the geoid. Alternatively, one may start from the modern surface gravity anomaly and apply the direct topographic effect on the anomaly, yielding the no-topography gravity anomaly. After downward continuation of this anomaly to sea-level and Stokes integration, a theoretically correct geoid height is obtained after the restoration of the topography by the PITE. The difference between the Bouguer and no-topography gravity anomalies (on the geoid or in space) is the “secondary indirect topographic effect”, which is a necessary correction in removing all topographic signals. In modern applications of an Earth gravitational model (EGM) in geoid determination a topographic correction is also needed in continental regions. Without the correction the error can range to a few metres in the highest mountains. The remove-compute-restore and Royal Institute of Technology (KTH) techniques for geoid determinations usually employ a combination of Stokes’ formula and an EGM. Both techniques require direct and indirect topographic corrections, but in the latter method these corrections are merged as a combined topographic effect on the geoid height. Finally, we consider that any uncertainty in the topographic density distribution leads to the same error in gravimetric and geometric geoid estimates, deteriorating GNSS-levelling as a tool for validating the topographic mass distribution correction in a gravimetric geoid model.
The Association of Fasting Glucose, Insulin, and C-Peptide, with 19-Year Incidence of Coronary Heart Disease in Older Japanese-American Men; the Honolulu Heart Program
Authors: Wahab Nazneem , Chen Randi , Curb Jess , Willcox Bradley , Rodriguez Beatriz
Published: April 2018

The role of fasting glucose, insulin levels, and C-peptide in coronary heart disease (CHD) in non-diabetic individuals remains uncertain. We examined the association between fasting glucose, insulin and C-peptide with the long-term incidence of CHD in Japanese-American men. In 1980–1982, from a random sample of the Honolulu Heart Program men (n = 1378), aged 61–81 years, data on several CHD and metabolic risk factors were obtained to examine the relation of fasting glucose, insulin and C-peptide to 19-year CHD incidence. Age-adjusted incidence of CHD increased with increasing quintiles of glucose, insulin and C-peptide. Age-adjusted CHD rates in the glucose quintiles were 11.9, 11.6, 14.4, 18.1 and 24.1 per 1000 person-years (trend p < 0.001). In individual Cox models (lowest quintiles of glucose, insulin and C-peptide as reference) the relative risks (95% confidence interval) of CHD incidence for the glucose quintiles adjusting for age, smoking, hypertension, cholesterol, physical activity, and body mass index, were 0.9 (0.6–1.4), 1.2 (0.8–1.8), 1.4 (0.9–2.2), and 1.7 (1.1–2.6), respectively (trend p = 0.004). Insulin and C-peptide were not significantly associated with CHD on multivariate analysis. Fasting glucose remained the only significant predictor of increased CHD risk (p = 0.003) in a model combining all 3 metabolic variables. In this cohort, only fasting glucose independently predicts long-term incidence of CHD. Age-adjusted insulin and C-peptide levels were associated with CHD incidence, but after adjustment for other risk factors, do not independently predict CHD.
A Rationale for Music Training to Enhance Executive Functions in Parkinson’s Disease: An Overview of the Problem
Authors: Lesiuk Teresa , Bugos Jennifer A. , Murakami Brea
Published: April 2018

Music listening interventions such as Rhythmic Auditory Stimulation can improve mobility, balance, and gait in Parkinson’s Disease (PD). Yet, the impact of music training on executive functions is not yet known. Deficits in executive functions (e.g., attention, processing speed) in patients with PD result in gait interference, deficits in emotional processing, loss of functional capacity (e.g., intellectual activity, social participation), and reduced quality of life. The model of temporal prediction and timing suggests two networks collectively contribute to movement generation and execution: the basal ganglia-thalamocortical network (BGTC) and the cerebellar-thalamocortical network (CTC). Due to decreases in dopamine responsible for the disruption of the BGTC network in adults with PD, it is hypothesized that rhythmic auditory cues assist patients through recruiting an alternate network, the CTC, which extends to the supplementary motor areas (SMA) and the frontal cortices. In piano training, fine motor finger movements activate the cerebellum and SMA, thereby exercising the CTC network. We hypothesize that exercising the CTC network through music training will contribute to enhanced executive functions. Previous research suggested that music training enhances cognitive performance (i.e., working memory and processing speed) in healthy adults and adults with cognitive impairments. This review and rationale provides support for the use of music training to enhance cognitive outcomes in patients with Parkinson’s Disease (PD).
How Urban Parks Offer Opportunities for Physical Activity in Dublin, Ireland
Authors: Burrows Eve , O’Mahony Margaret , Geraghty Dermot
Published: April 2018

Parks are an important part of the urban fabric of cities. They offer people the opportunity to connect with nature, engage in physical activity, find a haven away from the city noise, or spend time alone or with family and friends. This study examines the relative importance of park and park visit characteristics for 865 survey participants in Dublin, Ireland. The data is analyzed using a multinomial logistic regression model which can distinguish the relative importance of attributes. The model results demonstrate an improvement over proportional by chance accuracy, indicating that the model is useful. The results suggest that when and why individuals go to the park along with the proximity of their residence to the park influence visit frequency more than their age and gender and more than their impression of the sound levels in the park. The contribution of the results, in terms of their potential usefulness to planners, suggest that the priority should be on the provision of park space close to residential areas, so that individuals can engage in activities such as walking and relaxation, and that the quality of that space, in the context of noise levels at least, is less important.
Aerobic Mesophilic, Coliform, Escherichia coli, and Staphylococcus aureus Counts of Raw Meat from the Formal and Informal Meat Sectors in South Africa
Authors: Jaja Ishmael Festus , Green Ezekiel , Muchenje Voster
Published: April 2018

Foodborne disease (FBD) is a global public health concern, and foods from animal sources have been associated with outbreaks of food-related illness. In this study, animal carcasses from the two abattoirs (HT1 and HT2) in the formal meat sector (FMS) and slaughter points in the informal meat sector (INMS) were examined at two stages of slaughter (before washing and after washing) for aerobic colony counts (ACC) and total viable count (TCC), as well as Escherichia coli and Staphylococcus aureus count. At each stage, carcasses were sampled by swabbing at the neck, brisket, flank, and rump. ACC for beef, mutton, and pork carcasses at HT1 and HT2 before washing were between 2.5–5.8, 2.2–4.7, and 2.7–3.7 mean log CFU/cm2, respectively, and TCC count before washing was highest on the neck of cattle (6.3 ± 2.4) and after washing was highest on the perineal of sheep (5.7 ± 6.9). In the INMS, TCC count was highest on the brisket (6.9 ± 3.2) and in the neck (5.5 ± 2.4). Higher ACC values of 6.2–6.7 mean log CFU/cm2 were obtained in the INMS. The highest count for E. coli (4.2 mean log CFU/cm2) after washing was in the neck, while the highest count for S. aureus (4.0 mean log CFU/cm2) was in the flank. All bacteria count in the INMS exceeded acceptable limits, and washing did not significantly reduce microbial load in meat in the FMS and INMS. Bacteria count in the FMS and INMS exceeded acceptable standards. However, meat processed in the INMS poses a more significant risk of FBD to consumers.
Psychometric Evaluation of the Workstyle Short Form among Nursing Assistants with Work-Related Musculoskeletal Symptoms
Authors: Cheung Kin , Ching Shirley S. Y. , Ma Ka Yan , Szeto Grace
Published: April 2018

The Workstyle Short Form (24 items) (WSF-24) has been tested for its psychometric properties on work-related upper-extremity musculoskeletal symptoms (WRUEMSs) among office workers. However, the impact of workstyle should not only be limited to WRUEMSs and the sedentary workforce. The purpose of this study was to test the psychometric properties of the modified 24-item Chinese WSF (C-WSF-24) to identify work-related musculoskeletal symptoms (WRMSs) in various body parts among nursing assistants (NAs) working in nursing homes. Four hundred and thirty-nine NAs participated in the study. The results of the factor analysis were that a four-factor solution (working through pain, social reactivity at work, demands at work and breaks) accounted for 56.45% of the total variance. Furthermore, validation against known groups showed that the total score and subscale scores of the C-WSF-24 had the ability to discriminate between NAs with and without WRMSs in various body parts (such as low back and lower extremities). Additionally, C-WSF-24 had a statistically significant association with the contributing factors to WRMSs. This is the first study to examine the psychometric properties of the C-WSF-24 in the non-sedentary workforce, with a focus on various body parts of WRMSs. The results demonstrated that C-WSF-24 is reliable and valid for assessing WRMSs in various body parts among NAs.
The Adsorptive Removal of Fluoride from Aqueous Solution by Modified Sludge: Optimization Using Response Surface Methodology
Authors: Li Ying , Yang Shengke , Jiang Qianli , Fang Jie , Wang Wenke , Wang Yanhua
Published: April 2018

The sludge from the water supply plant was investigated to remove fluoride ions from the water. To improve the adsorption ability, the original sludge sample was treated with fuel oxidation, pyrolysis, hydrochloric acid, and sulphuric acid methods, and hydrochloric acid treatment improved the adsorption capacity of the sludge on the fluoride in water significantly, with a maximum adsorption capacity to 140 mg/kg. The adsorption experimental data was the well fitted pseudo-first-order model and the Langmuir isotherms model. SEM images and XRD patterns of the adsorbent were recorded to get a better insight into the adsorption process. The effect of three variables, hydrochloric acid treated sludge (HWS) dose, pH, and initial fluoride concentration were studied using a Box-Behnken statistical experimental design. The model of the adsorption and optimum conditions was investigated using the response surface methodology. The optimum removal efficiency of fluoride can reach 81.153% under the optimum condition: HWS dose of 14.10 g/L and pH value at 6.12. The effect of co-existing anions and the removal efficiency from the water were also studied. The results suggest that sludge from the water supply plant can be reused as a coagulant for the removal of fluoride from poor quality water.
Using the TensorFlow Deep Neural Network to Classify Mainland China Visitor Behaviours in Hong Kong from Check-in Data
Authors: Han Shanshan , Ren Fu , Wu Chao , Chen Ying , Du Qingyun , Ye Xinyue
Published: April 2018

Over the past decade, big data, including Global Positioning System (GPS) data, mobile phone tracking data and social media check-in data, have been widely used to analyse human movements and behaviours. Tourism management researchers have noted the potential of applying these data to study tourist behaviours, and many studies have shown that social media check-in data can provide new opportunities for extracting tourism activities and tourist behaviours. However, traditional methods may not be suitable for extracting comprehensive tourist behaviours due to the complexity and diversity of human behaviours. Studies have shown that deep neural networks have outpaced the abilities of human beings in many fields and that deep neural networks can be explained in a psychological manner. Thus, deep neural network methods can potentially be used to understand human behaviours. In this paper, a deep learning neural network constructed in TensorFlow is applied to classify Mainland China visitor behaviours in Hong Kong, and the characteristics of these visitors are analysed to verify the classification results. For the social science classification problem investigated in this study, the deep neural network classifier in TensorFlow provides better accuracy and more lucid visualisation than do traditional neural network methods, even for erratic classification rules. Furthermore, the results of this study reveal that TensorFlow has considerable potential for application in the human geography field.
DASSCAN: A Density and Adjacency Expansion-Based Spatial Structural Community Detection Algorithm for Networks
Authors: Wan You , Liu Yaolin
Published: April 2018

Existing spatial community detection algorithms are usually modularity based. Motivated by different applications, these algorithms build appropriate spatial null models to describe spatial effects on the connection of nodes. Then, by choosing certain modularity maximizing strategies, they try to find interesting community structures hidden behind the null models. In this paper, a novel structural similarity-based spatial network community is defined, which is based on the shared neighbors of nodes. In addition, there are two other special node roles defined: the spatial hub and outlier. Then, a density and adjacency expansion-based spatial structural community detection algorithm for networks (DASSCAN) is proposed for mining these communities, hubs and outliers. DASSCAN uses structural similarity to measure the relationship between nodes, and then, structurally similar and spatially adjacent nodes are merged into communities using a density-based clustering method and spatial adjacency expansion strategy. Comparative experiments on two kinds of Chinese train line networks clarified the accuracy and efficiency of DASSCAN in finding the spatial structural communities, spatial hubs and outliers. The communities found can be used to uncover more interesting spatial structural patterns, and the hubs and outliers are more accurate and have more valuable meanings.
Cytokine Expression and Macrophage Localization in Xenograft and Allograft Tumor Models Stimulated with Lipopolysaccharide
Authors: Masuda Junko , Shigehiro Tsukasa , Matsumoto Takuma , Satoh Ayano , Mizutani Akifumi , Umemura Chiho , Saito Shoki , Kijihira Mayumi , Takayama Eiji , Seno Akimasa , Murakami Hiroshi , Seno Masaharu
Published: April 2018

T cell-deficient mice such as nude mice are often used to generate tumor xenograft for the development of anticancer agents. However, the functionality of the other immune cells including macrophages, dendritic cells (DCs), and myeloid-derived suppressor cells (MDSCs) in the xenograft are largely unknown. Macrophages and dendritic cells (DCs) acquire functionally distinct properties in response to various environmental stimuli; the interaction of these cells with MDSCs in tumor microenvironments regulates cancer progression. Nude mice are less likely to reject human cancer cells because of major histocompatibility complex (MHC) mismatches. The tumor microenvironment in a xenograft, comprising human and mouse cells, exhibits more complex bidirectional signaling and function than that of allograft. Here, we evaluated the differences of myeloid cells between them. Plasma interferon-γ and interleukin-18 concentrations in the xenograft tumor model after lipopolysaccharide (LPS) administration were significantly higher than those in the allograft tumor model. MHC class I, II, and CD80 expression levels were increased in CD11b+ and MDSC populations after LPS administration in the spleen of a xenograft tumor model but not in that of an allograft tumor model. Additionally, the number of CD80- and mannose receptor C type 1 (MRC1)-expressing cells was decreased upon LPS administration in the tumor of the xenograft tumor. These results suggest that functions of macrophages and DCs are sustained in the xenograft, whereas their functions in response to LPS were suppressed in the allograft. The findings will encourage the consideration of the effects of myeloid cells in the xenograft for drug development.
ROS-Activated Ion Channels in Plants: Biophysical Characteristics, Physiological Functions and Molecular Nature
Authors: Demidchik Vadim
Published: April 2018

Ion channels activated by reactive oxygen species (ROS) have been found in the plasma membrane of charophyte Nitella flixilis, dicotyledon Arabidopsis thaliana, Pyrus pyrifolia and Pisum sativum, and the monocotyledon Lilium longiflorum. Their activities have been reported in charophyte giant internodes, root trichoblasts and atrichoblasts, pollen tubes, and guard cells. Hydrogen peroxide and hydroxyl radicals are major activating species for these channels. Plant ROS-activated ion channels include inwardly-rectifying, outwardly-rectifying, and voltage-independent groups. The inwardly-rectifying ROS-activated ion channels mediate Ca2+-influx for growth and development in roots and pollen tubes. The outwardly-rectifying group facilitates K+ efflux for the regulation of osmotic pressure in guard cells, induction of programmed cell death, and autophagy in roots. The voltage-independent group mediates both Ca2+ influx and K+ efflux. Most studies suggest that ROS-activated channels are non-selective cation channels. Single-channel studies revealed activation of 14.5-pS Ca2+ influx and 16-pS K+ efflux unitary conductances in response to ROS. The molecular nature of ROS-activated Ca2+ influx channels remains poorly understood, although annexins and cyclic nucleotide-gated channels have been proposed for this role. The ROS-activated K+ channels have recently been identified as products of Stellar K+ Outward Rectifier (SKOR) and Guard cell Outwardly Rectifying K+ channel (GORK) genes.
Molecular Pharmacology of VEGF-A Isoforms: Binding and Signalling at VEGFR2
Authors: Peach Chloe J. , Mignone Viviane W. , Arruda Maria Augusta , Alcobia Diana C. , Hill Stephen J. , Kilpatrick Laura E. , Woolard Jeanette
Published: April 2018

Vascular endothelial growth factor-A (VEGF-A) is a key mediator of angiogenesis, signalling via the class IV tyrosine kinase receptor family of VEGF Receptors (VEGFRs). Although VEGF-A ligands bind to both VEGFR1 and VEGFR2, they primarily signal via VEGFR2 leading to endothelial cell proliferation, survival, migration and vascular permeability. Distinct VEGF-A isoforms result from alternative splicing of the Vegfa gene at exon 8, resulting in VEGFxxxa or VEGFxxxb isoforms. Alternative splicing events at exons 5–7, in addition to recently identified posttranslational read-through events, produce VEGF-A isoforms that differ in their bioavailability and interaction with the co-receptor Neuropilin-1. This review explores the molecular pharmacology of VEGF-A isoforms at VEGFR2 in respect to ligand binding and downstream signalling. To understand how VEGF-A isoforms have distinct signalling despite similar affinities for VEGFR2, this review re-evaluates the typical classification of these isoforms relative to the prototypical, “pro-angiogenic” VEGF165a. We also examine the molecular mechanisms underpinning the regulation of VEGF-A isoform signalling and the importance of interactions with other membrane and extracellular matrix proteins. As approved therapeutics targeting the VEGF-A/VEGFR signalling axis largely lack long-term efficacy, understanding these isoform-specific mechanisms could aid future drug discovery efforts targeting VEGF receptor pharmacology.
Molecular Analysis of Sensory Axon Branching Unraveled a cGMP-Dependent Signaling Cascade
Authors: Dumoulin Alexandre , Ter-Avetisyan Gohar , Schmidt Hannes , Rathjen Fritz G.
Published: April 2018

Axonal branching is a key process in the establishment of circuit connectivity within the nervous system. Molecular-genetic studies have shown that a specific form of axonal branching—the bifurcation of sensory neurons at the transition zone between the peripheral and the central nervous system—is regulated by a cyclic guanosine monophosphate (cGMP)-dependent signaling cascade which is composed of C-type natriuretic peptide (CNP), the receptor guanylyl cyclase Npr2, and cGMP-dependent protein kinase Iα (cGKIα). In the absence of any one of these components, neurons in dorsal root ganglia (DRG) and cranial sensory ganglia no longer bifurcate, and instead turn in either an ascending or a descending direction. In contrast, collateral axonal branch formation which represents a second type of axonal branch formation is not affected by inactivation of CNP, Npr2, or cGKI. Whereas axon bifurcation was lost in mouse mutants deficient for components of CNP-induced cGMP formation; the absence of the cGMP-degrading enzyme phosphodiesterase 2A had no effect on axon bifurcation. Adult mice that lack sensory axon bifurcation due to the conditional inactivation of Npr2-mediated cGMP signaling in DRG neurons demonstrated an altered shape of sensory axon terminal fields in the spinal cord, indicating that elaborate compensatory mechanisms reorganize neuronal circuits in the absence of bifurcation. On a functional level, these mice showed impaired heat sensation and nociception induced by chemical irritants, whereas responses to cold sensation, mechanical stimulation, and motor coordination are normal. These data point to a critical role of axon bifurcation for the processing of acute pain perception.
Application of Finite Element Method to Analyze the Influences of Process Parameters on the Cut Surface in Fine Blanking Processes by Using Clearance-Dependent Critical Fracture Criteria
Authors: Wai Myint Phyo , Hagihara Seiya , Tanaka Toru , Taketomi Shinya , Tadano Yuichi
Published: April 2018

The correct choice of process parameters is important in predicting the cut surface and obtaining a fully-fine sheared surface in the fine blanking process. The researchers used the value of the critical fracture criterion obtained by long duration experiments to predict the conditions of cut surfaces in the fine blanking process. In this study, the clearance-dependent critical ductile fracture criteria obtained by the Cockcroft-Latham and Oyane criteria were used to reduce the time and cost of experiments to obtain the value of the critical fracture criterion. The Finite Element Method (FEM) was applied to fine blanking processes to study the influences of process parameters such as the initial compression, the punch and die corner radii and the shape and size of the V-ring indenter on the length of the sheared surface. The effects of stress triaxiality and punch diameters on the cut surface produced by the fine blanking process are also discussed. The verified process parameters and tool geometry for obtaining a fully-fine sheared SPCC surface are described. The results showed that the accurate and stable prediction of ductile fracture initiation can be achieved using the Oyane criterion.
Piezoelectric Response of Multi-Walled Carbon Nanotubes
Authors: Il’ina Marina V. , Il’in Oleg I. , Blinov Yuriy F. , Konshin Alexey A. , Konoplev Boris G. , Ageev Oleg A.
Published: April 2018

Recent studies in nanopiezotronics have indicated that strained graphene may exhibit abnormal flexoelectric and piezoelectric properties. Similar assumptions have been made with regard to the properties of carbon nanotubes (CNTs), however, this has not so far been confirmed. This paper presents the results of our experimental studies confirming the occurrence of a surface piezoelectric effect in multi-walled CNTs under a non-uniform strain. Using atomic force microscopy, we demonstrated the piezoelectric response of multi-walled CNTs under compression and bending. The current generated by deforming an individual CNT was shown to be −24 nA. The value of the surface potential at the top of the bundle of strained CNTs varied from 268 mV to −110 mV, depending on strain type and magnitude. We showed that the maximum values of the current and the surface potential can be achieved when longitudinal strain predominates in a CNT. However, increasing the bending strain of CNTs does not lead to a significant increase in current and surface potential, due to the mutual compensation of piezoelectric charges concentrated on the CNT side walls. The results of the study offer a number of opportunities and challenges for further fundamental research on the piezoelectric properties of carbon nanotubes as well as for the development of advanced CNT-based nanopiezotronic devices.
Ultralight Graphene/Carbon Nanotubes Aerogels with Compressibility and Oil Absorption Properties
Authors: Zhao Da , Yu Li , Liu Dongxu
Published: April 2018

Graphene aerogels have many advantages, such as low density, high elasticity and strong adsorption. They are considered to be widely applicable in many fields. At present, the most valuable research area aims to find a convenient and effective way to prepare graphene aerogels with excellent properties. In this work graphene/carbon nanotube aerogels are prepared through hydrothermal reduction, freeze-drying and high temperature heat treatment with the blending of graphene oxide and carbon nanotubes. A new reducing agent-ascorbic acid is selected to explore the best preparation process. The prepared aerogels have compression and resilience and oil absorption properties due to the addition of carbon nanotubes as designed.
Electric and Hydraulic Properties of Carbon Felt Immersed in Different Dielectric Liquids
Authors: Kossenko Alexey , Lugovskoy Svetlana , Averbukh Moshe
Published: April 2018

Electroconductive carbon felt (CF) material, having a permeable structure and significant electroconductive surface, is widely used for electrodes in numerous electrochemical applications such as redox flow batteries, fuel cells, electrochemical desalination apparatus, etc. The internal structure of CF is composed of different lengths of carbon filaments bonded together. This structure creates a large number of stochastically oriented and stochastically linked channels that have different lengths and cross sections. Therefore, the CF hydraulic permeability is similar to that of porous media and is determined by the internal empty volume and arrangement of carbon fibers. Its electroconductivity is ensured by the conductivity of the carbon filaments and by the electrical interconnections between fibers. Both of these properties (permeability and electrical conductivity) are extremely important for the efficient functioning of electrochemical devices. However, their influences counter each other during CF compressing. Increasing the stress on a felt element provides supplementary electrical contacts of carbon filaments, which lead to improved electrical conductivity. Thus, the active surface of the felt electrode is increased, which also boosts redox chemical reactions. On the other hand, compressed felt possesses reduced hydrodynamic permeability as a result of a diminished free volume of porous media and intrinsic channels. This causes increasing hydrodynamic expenditures of electrolyte pumping through electrodes and lessened cell (battery) efficiency. The designer of specific electrochemical systems has to take into account both of these properties when selecting the optimal construction for a cell. This article presents the results of measurements and novel approximating expressions of electrical and hydraulic characteristics of a CF during its compression. Since electrical conductivity plays a determining role in providing electrochemical reactions, it was measured in dry conditions and when the CF was immersed in several non-conductive liquids. The choice of such liquids prevented side effects of electrolyte ionic conductivity impact on electrical resistivity of the CF. This gave an opportunity to determine the influences of dielectric parameters of electrolytes to increase or decrease the density of interconnectivity of carbon fibers either between themselves or between them and electrodes. The experiments showed the influence of liquid permittivity on the conductivity of CF, probably by changing the density of fiber interconnections inside the felt.
Dependence of Reaction Time and Movement Speed on Task Complexity and Age
Authors: Darbutas Tomas , Juodžbalienė Vilma , Skurvydas Albertas , Kriščiūnas Aleksandras
Published: April 2018

The aim of this study was to determine the differences in reaction time, reaction complexity, and movement speed depending on age. Material and Methods. The study included 40 healthy subjects (20 young and 20 older women and men). The study was conducted at the Human Motorics Laboratory, Lithuanian Sports University. An analyzer DPA-1 of dynamic upper and lower limb movements was used for the research purposes. Results. The reaction time of the right arm of the young subjects was 0.26 s (SD, 0.01) and that of the left arm was 0.25 s (SD, 0.02), when an accuracy task was performed. The reaction time of the older subjects was 0.29 s (SD, 0.03) and 0.28 s (SD, 0.03) for the right and left arms, respectively. The reaction time of the right leg of the young subjects was 0.26 s (SD, 0.02) and that of the left leg was 0.27 s (SD, 0.03). The reaction time of the right and left legs of the older subjects was 0.33 s (SD, 0.02) and 0.35 s (SD, 0.04), respectively. The reaction of the young subjects was almost two times faster compared with the older persons after the accuracy task with each limb was accomplished. Conclusions. In case of movements with arms and legs, reaction time and movement speed directly depend on the complexity of a task. Reaction time and movement speed are slower for the older subjects in comparison with the young ones; the results worsen in proportion to the increasing complexity of a task.
Stargardt Disease Caused by a Rare Combination of Double Homozygous Mutations
Authors: Serapinas Danielius , Obrikytė Viltautė , Sakalauskas Raimundas
Published: April 2018

Stargardt disease is a juvenile macular degeneration most often inherited in an autosomal recessive pattern, characterized by decreased vision in the first 2 decades of life. This report presents a clinical case of Stargardt disease: a 10-year-old female patient complained of blurry vision, and in a 4-year period, her visual acuity was reduced from OD=0.3 and OS=0.3 to OD=0.08 and OS=0.1, respectively. A genetic analysis revealed a rare combination of 2 homozygous recessive mutations in the ABCA4 gene, which caused Stargardt disease. The presence of different genetic mechanisms leading to a severe disease phenotype can challenge molecular geneticists, ophthalmologists, and genetic counselors.
CTX-M-Producing Escherichia coli in Lithuania: Associations Between Sites of Infection, Coresistance, and Phylogenetic Groups
Authors: Giedraitienė Agnė , Vitkauskienė Astra , Ašmonienė Virginija , Plančiūnienė Rita , Šimonytė Sandrita , Pavilonis Alvydas , Arlet Guillaume
Published: April 2018

Increasing resistance of Escherichia coli (E. coli) to antibiotics, especially to the third-generation cephalosporins, has prompted studies on widespread resistance genes such as blaCTX-M and differentiation of E. coli to phylogenetic groups. The aim of this study was to determine the associations between the CTX-M type and the phylogenetic group, the site of infection, and coresistance in Lithuanian E. coli isolates producing β-lactamases. Material and Methods. A total of 90 E. coli ESBL strains were recovered from the lower respiratory tract, the urinary tract, sterile body sites, wounds, and other body sites between 2008 and 2012. The E. coli isolates resistant to at least 2 antibiotics with different modes of action along with resistance to cefotaxime were considered as multiresistant. The blaCTX-M, blaTEM, blaOXA-1, and blaSHV genes, the phylogenetic groups, and the resistance profiles were analyzed. Results. Of the 90 isolates, 84 (93.3%) were classified as multiresistant and 6 (6.6%) as resistant. The blaCTX-M-15 gene was the most prevalent gene followed by the blaCTX-M-14 and blaCTX-M-92 genes. The logistic regression analysis revealed the associations between CTX-M-15 and resistance to ceftriaxone, between CTX-M-14 and resistance to cefoxitin, aztreonam, ampicillin/sulbactam, ticarcillin/clavulanic acid, and tobramycin, and between CTX-M-92 and resistance to cefepime, piperacillin/tazobactam, gentamicin, and tobramycin. Conclusions. The results of this study showed a significant association between CTX-M-15, CTX-M-14, and CTX-M-92 β-lactamases and resistance to some antibiotics as well as CTX‑M-14 β-lactamase and phylogenetic group A in the Lithuanian population. The associations between the CTX-M type and the site of infection were not determined.