bluuebunny/crossref_metadata_2025 huggingface dataset:
Hysteresis Reduction for Organic Thin Film Transistors with Multiple Stacked Functional Zirconia Polymeric Films
Authors: Kwon Jin-Hyuk , Choi Ji-Hoon , Bae Jin-Hyuk , Park and Jaehoon
Published: November 2019

We show that transfer hysteresis for a pentacene thin film transistor (TFT) with a low-temperature solution-processed zirconia (ZrOx) gate insulator can be remarkably reduced by modifying the ZrOx surface with a thin layer of crosslinked poly(4-vinylphenol) (c-PVP). Pentacene TFTs with bare ZrOx and c-PVP stacked ZrOx gate insulators were fabricated, and their hysteresis behaviors compared. The different gate insulators exhibited no significant surface morphology or capacitance differences. The threshold voltage shift magnitude decreased by approximately 71% for the TFT with the c-PVP stacked ZrOx gate insulator compared with the bare ZrOx gate insulator, with 0.75 ± 0.05 and 0.22 ± 0.03 V threshold voltage shifts for the bare ZrOx and c-PVP stacked ZrOx gate insulators, respectively. The hysteresis reduction was attributed to effectively covering hysteresis-inducing charge trapping sites on ZrOx surfaces.
Drone-Action: An Outdoor Recorded Drone Video Dataset for Action Recognition
Authors: Perera Asanka G. , Law Yee Wei , Chahl Javaan
Published: November 2019

Aerial human action recognition is an emerging topic in drone applications. Commercial drone platforms capable of detecting basic human actions such as hand gestures have been developed. However, a limited number of aerial video datasets are available to support increased research into aerial human action analysis. Most of the datasets are confined to indoor scenes or object tracking and many outdoor datasets do not have sufficient human body details to apply state-of-the-art machine learning techniques. To fill this gap and enable research in wider application areas, we present an action recognition dataset recorded in an outdoor setting. A free flying drone was used to record 13 dynamic human actions. The dataset contains 240 high-definition video clips consisting of 66,919 frames. All of the videos were recorded from low-altitude and at low speed to capture the maximum human pose details with relatively high resolution. This dataset should be useful to many research areas, including action recognition, surveillance, situational awareness, and gait analysis. To test the dataset, we evaluated the dataset with a pose-based convolutional neural network (P-CNN) and high-level pose feature (HLPF) descriptors. The overall baseline action recognition accuracy calculated using P-CNN was 75.92%.
Emitter Signal Waveform Classification Based on Autocorrelation and Time-Frequency Analysis
Authors: Ma Zhiyuan , Huang Zhi , Lin Anni , Huang Guangming
Published: November 2019

Emitter signal waveform recognition and classification are necessary survival techniques in electronic warfare systems. The emitters use various techniques for power management and complex intra-pulse modulations, which can create what looks like a noisy signal to an intercept receiver, so emitter signal waveform recognition at a low signal-to-noise ratio (SNR) has gained increased attention. In this study, we propose an autocorrelation feature image construction technique (ACFICT) combined with a convolutional neural network (CNN) to maintain the unique feature of each signal, and a structure optimization for CNN input layer called hybrid model is designed to achieve image enhancement of the signal autocorrelation, which is different from using a single image combined with CNN to complete classification. We demonstrate the performance of ACFICT by comparing feature images generated by different signal pre-processing algorithms, and the evaluation indicators are signal recognition rate, image stability degree, and image restoration degree. This paper simulates six types of the signals by combining ACFICT with three types of hybrid model, the simulation results compared with the literature show that the proposed methods not only has a high universality, but also better adapts to waveform recognition at low SNR environment. When the SNR is –6 dB, the overall recognition rate of the method reaches 88%.
Transformerless High Step-Up DC-DC Converters with Switched-Capacitor Network
Authors: Duong Truong-Duy , Nguyen Minh-Khai , Tran Tan-Tai , Lim Young-Cheol , Choi Joon-Ho
Published: November 2019

High-voltage gain conversion is necessary for several applications, especially for low voltage renewable source applications. In order to achieve a high-voltage gain, the presented paper proposes a class of transformerless DC-DC converters based on three switched-capacitor networks. The proposed converters have the following characteristics: reduced voltage stress on the capacitors and power devices; obtained high voltage gain with small duty cycle; and reduced conduction losses in the power switches. To verify the operation principle of the proposed converters, the detailed analysis in different conditions of the proposed converters and a comparison considering existing topologies are also discussed in the paper. Moreover, the parameter selection and controller design for the converters are determined. Finally, to reconfirm the theoretical analysis, both the simulation and experimental results taken from a 400 W prototype operating at 60 kHz are given.
A New Wall Model for Large Eddy Simulation of Separated Flows
Authors: Fakhari Ahmad
Published: November 2019

The aim of this work is to propose a new wall model for separated flows which is combined with large eddy simulation (LES) of the flow field in the whole domain. The model is designed to give reasonably good results for engineering applications where the grid resolution is generally coarse. Since in practical applications a geometry can share body fitted and immersed boundaries, two different methodologies are introduced, one for body fitted grids, and one designed for immersed boundaries. The starting point of the models is the well known equilibrium stress model. The model for body fitted grid uses the dynamic evaluation of the von Kármán constant κ of Cabot and Moin (Flow, Turbulence and Combustion, 2000, 63, pp. 269–291) in a new fashion to modify the computation of shear velocity which is needed for evaluation of the wall shear stress and the near-wall velocity gradients based on the law of the wall to obtain strain rate tensors. The wall layer model for immersed boundaries is an extension of the work of Roman et al. (Physics of Fluids, 2009, 21, p. 101701) and uses a criteria based on the sign of the pressure gradient, instead of one based on the friction velocity at the projection point, to construct the velocity under an adverse pressure gradient and where the near-wall computational node is in the log region, in order to capture flow separation. The performance of the models is tested over two well-studied geometries, the isolated two-dimensional hill and the periodic two-dimensional hill, respectively. Sensitivity analysis of the models is also performed. Overall, the models are able to predict the first and second order statistics in a reasonable way, including the position and extension of the downward separation region.
Interdisciplinary Geosciences Perspectives of Tsunami Volume 2
Authors: Suppasri Anawat
Published: November 2019

Disaster related research has its own interdisciplinary perspectives connected to the disaster cycle (response, recovery, prevention, and preparedness). This special issue focuses on interdisciplinary geosciences perspectives of tsunami that cover the whole process of tsunami disasters (generation, propagation, impact assessment, psychological perspectives, and planning). This special issue collects tsunami research papers not only as lessons from the 2011 Great East Japan tsunami, but also from other areas in Japan (coastal defense structures, tsunami fires, economic loss assessment, and emergency planning) as well as other countries (morphological changes in Indonesia and building risk assessment in New Zealand. The order of the paper follows the tsunami disaster process and the connections between each paper show the interdisciplinary perspectives of tsunami research, which can also be used as a framework for other types of disaster research.
Simultaneous Hip and Distal Radius Fractures—Does It Make a Difference with Respect to Rehabilitation?
Authors: Dubljanin-Raspopović Emilija , Lj Marković-Denić , Kadija Marko , Tomanović Vujadinović Sanja , Tulić Goran , Selaković Ivan , Aleksić Milica
Published: November 2019

Introduction: A minority of patients with hip fractures sustain concomitant wrist fractures. Little is known about the rehabilitation outcome in this group of patients. Aim of study: Prospective investigation of functional outcome and survival in patients with combined hip and wrist fractures compared with patients who sustain an isolated hip fracture. Methods: 341 patients who presented with an acute hip fracture during a 12 month period were included in the study. Outcome at discharge and 4 months follow-up was compared between patients with isolated hip fractures and those patients who sustained simultaneous distal wrist fractures. Results: The actual incidence of concurrent hip and wrist fractures in our cohort was 4.7%. Patients who sustained a concurrent hip and wrist fracture showed no differences regarding short- and long-term functional outcome and survival. Conclusion: Our results imply that patients with simultaneous hip and wrist fractures have no difference in rehabilitative outcome. Future studies should further investigate the distinctive characteristics of this patient subgroup.
Medication Error Rate in Transition of Care: General Practitioner (GP) Referrals to a Regional Emergency Department
Authors: Prior Sarah J. , Cheek Colleen , Cheah Dong , Etherington Christopher , Williams Abigail , Reeves Nicole S.
Published: November 2019

Medication errors have a significant impact on patient outcomes, increase healthcare costs, and are a common cause of preventable morbidity. This single-site, observational, diagnostic accuracy study aimed to quantify medication discrepancies in transition of care from primary care to the emergency department (ED) over a 12-month period. Medication lists in General Practitioner (GP) referrals to a regional ED were examined against a Best Possible Medication History (BPMH) performed by a hospital pharmacist. One hundred and forty-three patients (25%) with computer-generated GP referrals to ED who were subsequently admitted to hospital had a BPMH taken; 135 (94%) of these had at least one medication discrepancy identified with a discrepancy rate of 67.18 discrepancies per 100 medications. Improving medication reconciliation in the community may reduce the burden associated with preventable medication errors. Whether this is achieved by more frequent GP-led medication review or community-based pharmacist medication review may depend on the community and available resources.
Psychopathic Disorder Subtypes Based on Temperament and Character Differences
Authors: Martínez-López J. Nicolás I. , Medina-Mora María-Elena , Robles-García Rebeca , Madrigal Eduardo , Juárez Francisco , Tovilla-Zarate Carlos-Alfonso , Reyes Cosette , Monroy Nadja , Fresán Ana
Published: November 2019

The concept of psychopathy has shifted from people who commit crimes to those with a particular personality and deviant behaviors. Although antisocial personality disorder is associated with psychopathy, it also seems common in individuals with narcissistic personality traits. Psychopathy may be the expression of earlier, persistent patterns of individual characteristics as personality. The psychobiological model of personality can be useful for determining whether the expression of psychopathy differs in accordance with personality dimensions and specific personality disorders. The aim was to compare temperament and character dimensions between individuals with psychopathy with comorbid predominant antisocial or narcissistic personality traits and control subjects and to determine which dimensions distinguish these groups. Control subjects (n = 80) and individuals with psychopathy (n = 80) were assessed using the Psychopathy Checklist-Reviewed, the Structured Clinical Interview for DSM-IV Axis II disorders and the Temperament and Character Inventory-Revised. Reward dependence and Self-Directedness distinguish psychopathic individuals with predominant narcissistic personality traits whereas Novelty Seeking and Self-Transcendence characterize those with antisocial personality traits. Individuals with antisocial or narcissistic psychopathy could be identified by their temperament and character traits. The expression of psychopathy differed in accordance with biologically based, environmentally shaped personality traits.
Controversies in the Science of Sedentary Behaviour and Health: Insights, Perspectives and Future Directions from the 2018 Queensland Sedentary Behaviour Think Tank
Authors: Biddle Stuart J.H. , Bennie Jason  A. , De Cocker Katrien , Dunstan David , Gardiner Paul A. , Healy Genevieve N. , Lynch Brigid , Owen Neville , Brakenridge Charlotte , Brown Wendy , Buman Matthew , Clark Bronwyn , Dohrn Ing-Mari , Duncan Mitch , Gilson Nicholas , Kolbe-Alexander Tracy , Pavey Toby , Reid Natasha , Vandelanotte Corneel , Vergeer Ineke , Vincent Grace E.
Published: November 2019

The development in research concerning sedentary behaviour has been rapid over the past two decades. This has led to the development of evidence and views that have become more advanced, diverse and, possibly, contentious. These include the effects of standing, the breaking up of prolonged sitting and the role of moderate-to-vigorous physical activity (MVPA) in the association between sedentary behaviour and health outcomes. The present aim is to report the views of experts (n = 21) brought together (one-day face-to-face meeting in 2018) to consider these issues and provide conclusions and recommendations for future work. Each topic was reviewed and presented by one expert followed by full group discussion, which was recorded, transcribed and analysed. The experts concluded that (a). standing may bring benefits that accrue from postural shifts. Prolonged (mainly static) standing and prolonged sitting are both bad for health; (b). ‘the best posture is the next posture’. Regularly breaking up of sitting with postural shifts and movement is vital; (c). health effects of prolonged sitting are evident even after controlling for MVPA, but high levels of MVPA can attenuate the deleterious effects of prolonged sitting depending on the health outcome of interest. Expert discussion addressed measurement, messaging and future directions.
Preliminary Analysis of the Factor Structure, Reliability and Validity of an Obsessive-Compulsive Disorder Screening Tool for Use with Adults in Malaysia
Authors: Che Din Normah , Mohd Nawi Liana , Ghazali Shazli Ezzat , Ahmad Mahadir , Ibrahim Norhayati , Said Zaini , Amit Noh , Subramaniam Ponnusamy
Published: November 2019

This is a preliminary study to examine the factor structure, reliability, and validity of an obsessive-compulsive disorder (OCD) screening tool for use in the Malaysian setting. A total of 199 Malaysian adults were recruited for this study. After cleaning and normalizing the data, 190 samples were left to be analyzed. Principle component analysis using varimax rotation was then performed to examine various factors derived from psychometric tools commonly used to assess OCD patients. The screening tool exhibited three factors that fit the description of obsessions and compulsions from the Diagnostic and Statistical Manual of Mental Disorders—5th Edition (DSM 5), as well as other common symptoms that co-morbid with OCD. The labels given to the three factors were: Severity of Compulsions, Severity of Obsessions, and Symptoms of Depression and Anxiety. Reliability analysis showed high reliability with a Cronbach’s alpha of 0.94, whereas convergent validity of the tool with the Yale Brown Obsessive-compulsive Scale—Self Report demonstrated good validity of r = 0.829. The three-factor model explained 68.91% of the total variance. Subsequent studies should focus on OCD factors that are culturally unique in the Malaysian context. Future research may also use online technology, which is cost-efficient and accessible, to further enhance the screening tool.
Heavy Metal in Paddy Soil and its Bioavailability in Rice Using In Vitro Digestion Model for Health Risk Assessment
Authors: Zulkafflee Nur Syahirah , Mohd Redzuan Nurul Adillah , Hanafi Zanjabila , Selamat Jinap , Ismail Mohd Razi , Praveena Sarva Mangala , Abdull Razis Ahmad Faizal
Published: November 2019

Rice ingestion is one of the major pathways for heavy metal bioaccumulation in human. This study aimed to measure the heavy metal content of paddy soils and its bioavailability in paddy grain in order to assess the health risk. In total, 10 rice samples (50 g each) of paddy plants were harvested from the Selangor and Terengganu areas of Malaysia to assess the bioavailability of heavy metal (As, Cd, Cu, Cr, and Pb) using the in vitro digestion model of Rijksinstituut voor Volksgezondheid en Milieu. The bioavailability of heavy metal concentrations in rice samples were analyzed using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The findings showed the bioavailability of heavy metal concentrations was decreased in the order Cr > Cu > Pb > As > Cd. Chromium was found to be the most abundant bioavailable heavy metal in cooked rice, which was the result of its high content in paddy soil. Hazard Quotient values for the bioavailability of the heavy metal studied were less than one indicating no non-carcinogenic health risks for adults and children. Meanwhile, the total Lifetime Cancer Risk exceeded the acceptable value showing a potential of carcinogenic health risk for both adults and children. The application of in vitro digestion model in assessing bioavailability of heavy metal produces a more realistic estimation of human health risks exposure. However, a regular monitoring of pollution in Selangor and Terengganu areas is crucial since the exposure of heavy metals through rice consumption poses the potential non-carcinogenic and carcinogenic health risk to the local residents.
Oxidative Degradation of Methylene Blue via PDS-Based Advanced Oxidation Process Using Natural Pyrite
Authors: Sun Liang , Hu Dehao , Zhang Ziyu , Deng Xiaoyan
Published: November 2019

H2O2- and PDS-based reactions are two typical advanced oxidation processes (AOPs). In this paper, a comparative study of H2O2/PDS-based AOPs employing natural pyrite as a catalyst to degrade methylene blue (MB) was reported. The adaptive pH range in pyrite/PDS extended from 3 to 11, in contrast to the narrow effective pH range of 3–7 in pyrite/H2O2. As a result of the iron leaching, a synergistic effect of both homogeneous and heterogeneous catalysis was observed in pyrite/PDS, whereas heterogeneous catalytic oxidation dominated pyrite/H2O2. Furthermore, the batch results showed that the MB removal by pyrite/PDS was highly dependent on chemical conditions (e.g., pH, pyrite and PDS concentration, temperature). Powerful SO4•− was generated by pyrite rapidly under acidic or weakly acidic conditions, while SO4•− and PDS were assumed by OH− under alkaline condition. The lower pyrite loading (from 0.1 to 0.5 g/L) was affected the removal efficiency obviously, while the scavenging of SO4•− did not seem to be remarkable with the excessive amounts of pyrite (>0.5 g/L). Excessive amounts of PDS (>2 mmol/L) might negatively affect the pyrite/PDS system. The reaction temperature that increased from 20 to 40 °C had a positive effect on the degradation of MB. SEM and XRD showed that the passivation of catalyst did not occur due to the strong acid-production ability of pyrite/PDS, inhibiting the formation of Fe-oxide covering the pyrite surface.
Subtyping of Adolescents with School Refusal Behavior: Exploring Differences Across Profiles in Self-Concept
Authors: Gonzálvez Carolina , Díaz-Herrero Ángela , Vicent María , Sanmartín Ricardo , Pérez-Sánchez Antonio M. , García-Fernández José M.
Published: November 2019

Not all adolescents with school attendance problems attribute their behavior to the same causes. Knowing the subtypes of students who reject school and their relationship with new variables, such as self-concept, is an unresolved task. This study aimed to identify different school refusal behavior profiles and to determine whether these profiles differed from each other based on the scores of the eleven dimensions of self-concept (Physical appearance, Physical abilities, Parent relations, Same-sex relations, Opposite-sex relations, Honesty, Emotional stability, Self-esteem, Verbal, Math, and General school). The participants were 1315 Spanish students (57.6% male) aged 12–18 years (M = 15.21; SD = 1.74). The School Refusal Assessment Scale-Revised and the Self-Description Questionnaire II-Short Form were administered. A latent class analysis revealed four school refusal behavior profiles: Moderately High School Refusal Behavior, Moderately Low School Refusal Behavior, Mixed School Refusal Behavior and Non-School Refusal Behavior. The results indicated that the Mixed School Refusal Behavior group was the most maladaptive profile and revealed the lowest mean scores on self-concept. In contrast, Non-School Refusal and Moderately Low School Refusal Behavior groups revealed the highest scores in all dimensions of self-concept. Implications for working toward the prevention of school refusal in students with low self-concept are discussed.
Modelling and Visualizing Holographic 3D Geographical Scenes with Timely Data Based on the HoloLens
Authors: Wang Wei , Wu Xingxing , He An , Chen Zeqiang
Published: November 2019

Commonly, a three-dimensional (3D) geographic information system (GIS) is based on a two-dimensional (2D) visualization platform, hindering the understanding and expression of the real world in 3D space that further limits user cognition and understanding of 3D geographic information. Mixed reality (MR) adopts 3D display technology, which enables users to recognize and understand a computer-generated world from the perspective of 3D glasses and solves the problem that users are restricted to the perspective of a 2D screen, with a broad application foreground. However, there is a gap, especially dynamically, in modelling and visualizing a holographic 3D geographical Scene with GIS data/information under the development mechanism of a mixed reality system (e.g., the Microsoft HoloLens). This paper attempts to propose a design architecture (HoloDym3DGeoSce) to model and visualize holographic 3D geographical scenes with timely data based on mixed reality technology and the Microsoft HoloLens. The HoloDym3DGeoSce includes two modules, 3D geographic scene modelling with timely data and HoloDym3DGeoSce interactive design. 3D geographic scene modelling with timely data dynamically creates 3D geographic scenes based on Web services, providing materials and content for the HoloDym3DGeoSce system. The HoloDym3DGeoSce interaction module includes two methods: Human–computer physical interaction and human–computer virtual–real interaction. The human–computer physical interaction method provides an interface for users to interact with virtual geographic scenes. The human–computer virtual–real interaction method maps virtual geographic scenes to physical space to achieve virtual and real fusion. According to the proposed architecture design scheme, OpenStreetMap data and the BingMap Server are used as experimental data to realize the application of mixed reality technology to the modelling, rendering, and interacting of 3D geographic scenes, providing users with a stronger and more realistic 3D geographic information experience, and more natural human–computer GIS interactions. The experimental results show that the feasibility and practicability of the scheme have good prospects for further development.
Deubiquitinating Enzymes: A Critical Regulator of Mitosis
Authors: Park Jinyoung , Cho Jinhong , Kim Eunice EunKyeong , Song Eun Joo
Published: November 2019

Mitosis is a complex and dynamic process that is tightly regulated by a large number of mitotic proteins. Dysregulation of these proteins can generate daughter cells that exhibit genomic instability and aneuploidy, and such cells can transform into tumorigenic cells. Thus, it is important for faithful mitotic progression to regulate mitotic proteins at specific locations in the cells at a given time in each phase of mitosis. Ubiquitin-dependent modifications play critical roles in this process by regulating the degradation, translocation, or signal transduction of mitotic proteins. Here, we review how ubiquitination and deubiquitination regulate the progression of mitosis. In addition, we summarize the substrates and roles of some deubiquitinating enzymes (DUBs) crucial for mitosis and describe how they contribute error correction during mitosis and control the transition between the mitotic phases.
Identification of Novel PI3Kδ Selective Inhibitors by SVM-Based Multistage Virtual Screening and Molecular Dynamics Simulations
Authors: Liang Jing-wei , Wang Shan , Wang Ming-yang , Li Shi-long , Li Wan-qiu , Meng Fan-hao
Published: November 2019

Phosphoinositide 3 kinase delta (PI3Kδ) is a lipid kinase that has been implicated in a variety of immune mediated disorders. The research on isoform selectivity was crucial for reducing side effects. In the current study, an optimized hierarchical multistage virtual screening method was utilized for screening the PI3Kδ selective inhibitors. The method sequentially applied a support vector machine (SVM), a protein ligand interaction fingerprint (PLIF) pharmacophore, and a molecular docking approach. The evaluation of the validation set showed a high hit rate and a high enrichment factor of 75.1% and 301.66, respectively. This multistage virtual screening method was then utilized to screen the NCI database. From the final hit list, Compound 10 has great potential as the PI3Kδ inhibitor with micromolar inhibition in the PI3Kδ kinase activity assay. This compound also shows selectivity against PI3Kδ kinase. The method combining SVM, pharmacophore, and docking was capable of screening out the compounds with potential PI3Kδ selective inhibitors. Moreover, structural modification of Compound 10 will contribute to investigating the novel scaffold and designing novel PI3Kδ inhibitors.
GaAs-Based InPBi Quantum Dots for High Efficiency Super-Luminescence Diodes
Authors: Zhang Liyao , Song Yuxin , Gong Qian
Published: November 2019

InPBi exhibits broad and strong photoluminescence at room temperature, and is a potential candidate for fabricating super-luminescence diodes applied in optical coherence tomography. In this paper, the strained InPBi quantum dot (QD) embedded in the AlGaAs barrier on a GaAs platform is proposed to enhance the light emission efficiency and further broaden the photoluminescence spectrum. The finite element method is used to calculate the strain distribution, band alignment and confined levels of InPBi QDs. The carrier recombinations between the ground states and the deep levels are systematically investigated. A high Bi content and a flat QD shape are found preferable for fabricating super-luminescence diodes with high efficiency and a broad emission spectrum.
Biomimetic Synthesis of Nanocrystalline Hydroxyapatite Composites: Therapeutic Potential and Effects on Bone Regeneration
Authors: Fang Chih-Hsiang , Lin Yi-Wen , Lin Feng-Huei , Sun Jui-Sheng , Chao Yuan-Hung , Lin Hung-Ying , Chang Zwei-Chieng
Published: November 2019

The development of a novel alloplastic graft with both osteoinductive and osteoconductive properties is still necessary. In this study, we tried to synthesize a biomimetic hydroxyapatite microspheres (gelatin/nano-hydroxyapatite microsphere embedded with stromal cell-derived factor-1: GHM-S) from nanocrystalline hydroxyapatites and to investigate their therapeutic potential and effects on bone regeneration. In this study, hydroxyapatite was synthesized by co-precipitation of calcium hydroxide and orthophosphoric acid to gelatin solution. The microbial transglutaminase was used as the agent to crosslink the microspheres. The morphology, characterization, and thermal gravimetric analysis of microspheres were performed. SDF-1 release profile and in vitro biocompatibility and relative osteogenic gene expression were analyzed, followed by in vivo micro-computed tomography study and histological analysis. The synthesized hydroxyapatite was found to be similar to hydroxyapatite of natural bone tissue. The stromal cell-derived factor-1 was embedded into gelatin/hydroxyapatite microsphere to form the biomimetic hydroxyapatite microsphere. The stromal cell-derived factor-1 protein could be released in a controlled manner from the biomimetic hydroxyapatite microsphere and form a concentration gradient in the culture environment to attract the migration of stem cells. Gene expression and protein expression indicated that stem cells could differentiate or develop into pre-osteoblasts. The effect of bone formation by the biomimetic hydroxyapatite microsphere was assessed by an in vivo rats’ alveolar bone defects model and confirmed by micro-CT imaging and histological examination. Our findings demonstrated that the biomimetic hydroxyapatite microsphere can enhance the alveolar bone regeneration. This design has potential be applied to other bone defects.
Role of the Aryl Hydrocarbon Receptor in Environmentally Induced Skin Aging and Skin Carcinogenesis
Authors: Vogeley Christian , Esser Charlotte , Tüting Thomas , Krutmann Jean , Haarmann-Stemmann Thomas
Published: November 2019

The skin is constantly exposed to a variety of environmental threats, including solar electromagnetic radiation, microbes, airborne particulate matter, and chemicals. Acute exposure to these environmental factors results in the activation of different signaling pathways that orchestrate adaptive stress responses to maintain cell and tissue homeostasis. Chronic exposure of skin to these factors, however, may lead to the accumulation of damaged macromolecules and loss of cell and tissue integrity, which, over time, may facilitate aging processes and the development of aging-related malignancies. One transcription factor that is expressed in all cutaneous cells and activated by various environmental stressors, including dioxins, polycyclic aromatic hydrocarbons, and ultraviolet radiation, is the aryl hydrocarbon receptor (AHR). By regulating keratinocyte proliferation and differentiation, epidermal barrier function, melanogenesis, and immunity, a certain degree of AHR activity is critical to maintain skin integrity and to adapt to acute stress situations. In contrast, a chronic activation of cutaneous AHR signaling critically contributes to premature aging and the development of neoplasms by affecting metabolism, extracellular matrix remodeling, inflammation, pigmentation, DNA repair, and apoptosis. This article provides an overview of the detrimental effects associated with sustained AHR activity in chronically stressed skin and pinpoints AHR as a promising target for chemoprevention.
Adopting Augmented Reality to Engage Higher Education Students in a Museum University Collection: the Experience at Roma Tre University
Authors: Poce Antonella , Amenduni Francesca , De Medio Carlo , Valente Mara , Re Maria Rosaria
Published: November 2019

University museums are powerful resource centres in higher education. In this context, the adoption of digital technologies can support personalised learning experience within the university museum. The aim of the present contribution is to present a case study carried out at the Department of Educational Sciences at Roma Tre University with a group of 14 master’s degree students. Students were involved in a 2-h workshop in which they were invited to test augmented reality technology through a web app for Android. At the end of the visit participants were required to fill in a questionnaire with both open-ended and closed-ended questions aimed at investigating their ideas on the exhibition and their critical thinking level. Students appreciated the exhibition, especially its multimodality. Most of the frequent themes identified in open-ended answers are related to critical and visual thinking. Despite the positive overall evaluation, there is still room for improvement, both in terms of technology and educational design.
Potential Pathways and Genes Involved in Lac Synthesis and Secretion in Kerria chinensis (Hemiptera: Kerriidae) Based on Transcriptomic Analyses
Authors: Wang Weiwei , Liu Pengfei , Lu Qin , Ling Xiaofei , Zhang Jinwen , Chen Ming-Shun , Chen Hang , Chen Xiaoming
Published: November 2019

Lac is a type of natural resin secreted by lac insects and is widely used in the military and other industries because of its excellent adhesion and insulation properties. The main ingredients of lac are lactones and lactides, which are formed from hydroxy fatty acids and sesquiterpene esters. In this study, we measured lac secretion rates by the insect Kerria chinensis at different developmental stages and identified lac secretion-minimum and lac secretion-active stages of the insect. We then analyzed transcriptomes of lac secretion-minimum and lac secretion-active stages of the insect. Based on expression profiles of genes in different stages of the insect, we identified pathways and genes that are potentially involved in lac synthesis and secretion in K. chinensis. Our study lays a foundation for future studies to reveal the molecular mechanisms and pathways of lac synthesis and secretion in this beneficial insect.
Heat Transfer and Thermal Management of Interior Permanent Magnet Synchronous Electric Motor
Authors: Wu Pey-Shey , Hsieh Min-Fu , Cai Wei Ling , Liu Jen-Hsiang , Huang Yun-Ting , Caceres Jose Fernando , Chang Shyy Woei
Published: November 2019

Geometric complexities and multi-physical phenomena add difficulties for predicting the thermal field and hence thermal management of an electric motor. A numerical design model that combined electromagnetic and thermal-fluid analysis was proposed for disclosing the detailed temperature distributions of each component in an electric motor. The thermal fluid analysis implemented ANSYS-Fluent code to unravel the thermal field of the interior permanent magnet synchronous electric motor fitted with a smooth or novel spirally twisted channel in the cooling water jacket of a stator with and without shaft cooling. In accordance with the thermal powers converted from the various electromagnetic losses of the electric motor, the complex heat conduction model with realistic thermal boundary conditions was formulated. Initially, the turbulent flow structures and channel averaged Nusselt numbers of the spiral channels without and with the sectional twist were comparatively examined for acquiring the convective thermal boundary conditions in the water jacket. With the high thermal conductivity of the aluminum water jacket, the heat-transfer improvements from the smooth-spiral-channel conditions by using the twisted spiral channel were effective for reducing the average temperatures by about 10% but less effective for altering the characteristic thermal field in the water jacket. At 1290 < Dn < 6455 or 5000 < Re < 25,000 for the spiral channel flows, the channel average Nusselt numbers ratios between the smooth and twisted spiral channels were elevated to 1.18–1.09 but decreased with the increase of Dn or Re. A set of heat-transfer correlations for estimating the Nusselt numbers of Taylor flow in the rotor-to-stator air gap was newly devised from the data available in the literature. While the cooling effectiveness of the water jacket and shaft was boosted by the sectional twists along the spiral channel of the water jacket, the presence of Taylor flow in the annual air gap prohibited the effective rotor-to-stator heat transmission, leading to hot spots in the rotor. By way of airflow cooling through the rotating hollow shaft, the high temperatures in the rotor were considerably moderated. As the development of Taylor flow between the rotor and stator was inevitable, the development of active or passive rotor cooling schemes was necessary for extending the power density of an electric motor. Unlike the previous thermal circuit or lumped-parameter thermal model that predicted the overall temperatures of motor components, the present coupled electromagnetic and thermal-fluid model can reveal the detailed temperature distributions in an electric motor to probe the local hot spots of each component in order to avoid overheating at the early design stage.
Thermal Ageing of a Hybrid Composite Rod for Next Generation Overhead Power Lines
Authors: Minard Gaelle , Colin Xavier
Published: November 2019

The thermal stability of a hybrid composite rod, made of epoxy-anhydride matrix reinforced with both unidirectional carbon and glass fibers, has been evaluated between 180 and 210 °C in different nitrogen/oxygen gas mixtures with several conventional but complementary laboratory techniques such as Fourier transform infrared spectrometry, thermogravimetry, differential calorimetry, optical microscopy, and three-point bending. Thermolysis predominates in the carbon-fiber core, where it induces an efficient chain scission process, leading to a decrease in the glass transition temperature and the formation of small macromolecular fragments, presumably diacids. These very polar fragments remain trapped in the carbon core, where they initiate micro-cavities when their concentration exceeds the solubility threshold. These micro-cavities accumulate in rich-matrix regions, where they coalesce to form apparent large cracks. They are thus responsible for the catastrophic decrease in elastic and fracture properties of the composite rod. In contrast, thermal oxidation affects a too thin superficial layer (typically 60 µm) of the glass-fiber shell to change significantly the global mechanical behavior of the composite rod. Based on these experimental observations, a kinetic model has been proposed to predict the initiation and development of damage in the composite rod. Its validity is successfully checked by comparing its predictions with the experimental results.
Intratidal and Subtidal Circulation in a Tropical Estuary during Wet Season: The Maroni, French Guiana
Authors: Ross Lauren , Sottolichio Aldo , Maury Tanguy , Lesourd Sandric , Gardel Antoine
Published: November 2019

Observations of water level, current velocity, river discharge, wind and salinity were collected in the Maroni estuary, on the border of French Guiana and Suriname during the wet season of 2018 to explore subtidal circulation patterns. Measurements are complimented by the application of analytical models with an aim to diagnose forcing mechanisms responsible for producing subtidal flows during the day of data collection and to extrapolate these findings to other time periods with variable wind and river forcing. Subtidal along-channel flows were found to be dominated by river discharge, with seaward directed velocities found throughout the channel section reaching 40 cm s − 1 . This pattern was altered with strong southwesterly winds, which produced and inverse gravitational circulation pattern despite the elevated river discharge. Secondary, or cross-channel flows, displayed a three-layer vertical structure in the main channel due to a combination of channel curvature and tidal asymmetry in the lateral baroclinic pressure gradient. The pressure gradient was produced by a salinity intrusion front that only manifested in the channel during flood tide. This is the first comprehensive study of tidal and subtidal flow dynamics in the Maroni estuary.
Investigation of the Relationship between Compressive Strength and Hydrate Formation Behavior of Low-Temperature Cured Cement upon Addition of a Nitrite-Based Accelerator
Authors: Kim Jihoon , Honda Daiki , Choi Heesup , Hama Yukio
Published: November 2019

When concrete is used for construction in cold-temperature regions, cold-resistant accelerators based on calcium nitrite (Ca(NO2)2) and calcium nitrate (Ca(NO3)2) are added to prevent early freezing damage. Although cold-resistant accelerators increase the early compressive strength and prevent early freezing damage by promoting cement hydration, the strength enhancement effect owing to the formation of such hydrates has not been evaluated quantitatively thus far. This study covers various types of analysis to understand the relationship between cement hydrate formation behavior and strength development upon the addition of varying amounts of nitrite-based accelerator. We find that the early compressive strength is enhanced by the addition of nitrite-based accelerator via the promotion of the relative production of monosulfate and C-S-H in the early age. However, the development of compressive strength decreases with an increase in the curing age. Furthermore, we find that the promotion of hydration reactions at an early age with the addition of nitrite-based accelerator can affect the formation ratio of each hydrate at a late age. We believe our findings can significantly contribute to developments in concrete application and allied fields.
A Facile Method to Fabricate Anisotropic Extracellular Matrix with 3D Printing Topological Microfibers
Authors: Gu Zhen , Gao Zili , Liu Wenli , Wen Yongqiang , Gu Qi
Published: November 2019

Natural tissues and organs have different requirements regarding the mechanical characteristics of response. It is still a challenge to achieve biomaterials with anisotropic mechanical properties using an extracellular matrix with biological activity. We have improved the ductility and modulus of the gelatin matrix using 3D printed gelatin microfibers with different concentrations and topologies and, at the same, time achieved anisotropic mechanical properties. We successfully printed flat microfibers using partially cross-linked gelatin. We modified the 10% (w/v) gelatin matrix with microfibers consisting of a gelatin concentration of 14% (w/v), increasing the modulus to about three times and the elongation at break by 39% in parallel with the fiber direction. At the same time, it is found that the microfiber topology can effectively change the matrix ductility, and changing the modulus of the gelatin used in the microfiber can effectively change the matrix modulus. These findings provide a simple method for obtaining active biological materials that are closer to a physiological environment.
Effect of Sintering on In Vivo Biological Performance of Chemically Deproteinized Bovine Hydroxyapatite
Authors: De Carvalho Bruno , Rompen Eric , Lecloux Geoffrey , Schupbach Peter , Dory Emilie , Art Jean-François , Lambert France
Published: November 2019

The influence of the manufacturing process on physicochemical properties and biological performance of xenogenic biomaterials has been extensively studied, but its quantification on bone-to-material contact remains poorly investigated. The aim of this study was to investigate the effect of different heat treatments of an experimental chemically-deproteinized bovine hydroxyapatite in vivo in terms of new bone formation and osteoconductivity. Protein-free hydroxyapatite from bovine origin was produced under sub-critical conditions and then either sintered at 820 °C or 1200 °C. Structural and morphological properties were assessed by scanning electron microscopy (SEM), measurement of surface area and X-ray diffractometry (XRD). The materials were then implanted in standardized alveolar bone defects in minipigs and histomorphometric evaluations were performed using non-decalcified sections. Marked topographical differences were observed by SEM analysis. As the sintering temperature of the experimental material increased, the surface area significantly decreased while crystallite size increased. In vivo samples showed that the highly sintered BHA presented a significantly lower percentage of newly formed bone than the unheated one (p = 0.009). In addition, the percentage of bone-to-material contact (BMC) was significantly lowered in the highly sintered group when compared to the unsintered (p = 0.01) and 820 °C sintered (p = 0.02) groups. Non-sintered or sintered at 820 °C BHA seems to maintain a certain surface roughness allowing better bone regeneration and BMC. On the contrary, sintering of BHA at 1200 °C has an effect on its morphological and structural characteristics and significantly modify its biological performance (osteoconductivity) and crystallinity.
Adaptive Volume Control in Titanium Alloy for High Temperature Performance
Authors: Li Pei , Sun Xun , Zhang Tianlong , Zhang Hualei , Wang Dong , Sun Qiaoyan , Xiao Lin , Sun Jun
Published: November 2019

With the increase of time, the shrinkage of materials at fixed temperature could enhance the failure of fasteners. We report a potential way to alter the volume/length of alloy automatically through isothermal aging due to pseudospinodal decomposition mechanism. The volume of Ti-10V-2Fe-3Al alloy first shrunk and then expanded during isothermal aging at 550 °C. It can fit tightly and make up for volume loss. Transmission electron microscopy observation exhibits no obvious coarsening of intragranular α phase with the increasing time. However, composition evolution with time shows a gradual change through energy dispersive spectrometer analysis. The result shows that β stabilizers, V and Fe, are prone to diffuse to the β matrix, while α stabilizers, Al, prefer to segregate to the α phase. First principle calculations suggest that the structure transition for β to α cause the first decrease of volume, and the diffusion of V, Fe and Al is the origin of the later abnormal increase of volume.
Chain Model for Carbon Nanotube Bundle under Plane Strain Conditions
Authors: Korznikova Elena A. , Rysaeva Leysan Kh. , Savin Alexander V. , Soboleva Elvira G. , Ekomasov Evgenii G. , Ilgamov Marat A. , Dmitriev Sergey V.
Published: November 2019

Carbon nanotubes (CNTs) have record high tensile strength and Young’s modulus, which makes them ideal for making super strong yarns, ropes, fillers for composites, solid lubricants, etc. The mechanical properties of CNT bundles have been addressed in a number of experimental and theoretical studies. The development of efficient computational methods for solving this problem is an important step in the design of new CNT-based materials. In the present study, an atomistic chain model is proposed to analyze the mechanical response of CNT bundles under plane strain conditions. The model takes into account the tensile and bending rigidity of the CNT wall, as well as the van der Waals interactions between walls. Due to the discrete character of the model, it is able to describe large curvature of the CNT wall and the fracture of the walls at very high pressures, where both of these problems are difficult to address in frame of continuum mechanics models. As an example, equilibrium structures of CNT crystal under biaxial, strain controlled loading are obtained and their thermal stability is analyzed. The obtained results agree well with previously reported data. In addition, a new equilibrium structure with four SNTs in a translational cell is reported. The model offered here can be applied with great efficiency to the analysis of the mechanical properties of CNT bundles composed of single-walled or multi-walled CNTs under plane strain conditions due to considerable reduction in the number of degrees of freedom.