bluuebunny/crossref_metadata_2025 huggingface dataset:
Does Sleep Mediate the Association between School Pressure, Physical Activity, Screen Time, and Psychological Symptoms in Early Adolescents? A 12-Country Study
Authors: Vandendriessche Ann , Ghekiere Ariane , Van Cauwenberg Jelle , De Clercq Bart , Dhondt Karlien , DeSmet Ann , Tynjälä Jorma , Verloigne Maïté , Deforche Benedicte
Published: March 2019

This study examines the mediating role of sleep duration and sleep onset difficulties in the association of school pressure, physical activity, and screen time with psychological symptoms in early adolescents. Data were retrieved from 49,403 children (13.7 ± 1.6 years old, 48.1% boys) from 12 countries participating in the World Health Organization (WHO) “Health Behaviour in School-aged Children” 2013/2014 study. A validated self-report questionnaire assessed psychological symptoms (feeling low, irritability or bad temper, feeling nervous), school pressure, physical activity (number of days/week 60 min moderate-to-vigorous), screen time, sleep duration on week- and weekend days, and perceived difficulties in getting asleep. Multilevel mediation analyses were conducted. School pressure and screen time were positively associated with psychological symptoms, whereas physical activity was negatively associated. With the exception of sleep duration in the association between physical activity and psychological symptoms, all associations were significantly mediated by sleep duration on week- and weekend days and sleep onset difficulties. Percentages mediated ranged from 0.66% to 34.13%. This study partly explains how school pressure, physical activity, and screen time are related to adolescents’ psychological symptoms. Future interventions improving adolescents’ mental well-being could target schoolwork, physical activity, and screen time, as these behaviours are directly and indirectly (through sleep) related to psychological symptoms.
New Health Care Reform and Impoverishment among Chronic Households in China: A Random-Intercept Approach
Authors: Xu Yongjian , Garrib Anupam , Zhou Zhongliang , Wang Duolao , Gao Jianmin , Yang Xiaowei , Fan Xiaojing , Chen Gang
Published: March 2019

High out-of-pocket (OOP) payments for chronic disease care often contribute directly to household poverty. Although previous studies have explored the determinants of impoverishment in China, few published studies have compared levels of impoverishment before and after the New Health Care Reform (NHCR) in households with members with chronic diseases (hereafter referred to as chronic households). Our study explored this using data from the fourth and fifth National Health Service Surveys conducted in Shaanxi Province. In total, 1938 households in 2008 and 7700 households in 2013 were included in the analysis. Rates of impoverishment were measured using a method proposed by the World Health Organization. Multilevel logistic modeling was used to explore the influence of the NHCR on household impoverishment. Our study found that the influence of NHCR on impoverishment varied by residential location. After the reform, in rural areas, there was a significant decline in impoverishment, although the impoverishment rate remained high. There was little change in urban areas. In addition, impoverishment in the poorest households did not decline after the NHCR. Our findings are important for policy makers in particular for evaluating reform effectiveness, informing directions for health policy improvement, and highlighting achievements in the efforts to alleviate the economic burden of households that have members with chronic diseases.
Bibliometric Analysis of Algal-Bacterial Symbiosis in Wastewater Treatment
Authors: Qi Yun , Chen Xingyu , Hu Zhan , Song Chunfeng , Cui Yuanlu
Published: March 2019

In recent years, the algae-bacteria symbiotic system has played a significant role in the sustainable development of wastewater treatment. With the continuous expansion of research outputs, publications related to wastewater treatment via algal-bacterial consortia appear to be on the rise. Based on SCI-EXPANDED database, this study investigated the research activities and tendencies of algae-bacteria symbiotic wastewater treatment technology by bibliometric method from 1998 to 2017. The results indicated that environmental sciences and ecology was the most productive subject categories, followed by engineering. Bioresource Technology was the most prominent journal in this field with considerable academic influence. China (146), USA (139) and Spain (76) had the largest amount of publications. Among them, USA was in a leading position in international cooperation, with the highest h-index (67) in 79 countries/territories. The cooperation between China and USA was the closest. The cooperative publishing rate of the Chinese Academy of Sciences was 83.33%, but most of them were in cooperation with domestic institutions, while international cooperation was relatively limited. Methane production, biofuel production, and extracellular polymeric substance were future focal frontiers of research, and this field had gradually become a multi-perspective and inter-disciplinary approach combining biological, environmental and energy technologies.
Evaluation of Implementing a Home-Based Fall Prevention Program among Community-Dwelling Older Adults
Authors: Olij Branko F. , Erasmus Vicki , Barmentloo Lotte M. , Burdorf Alex , Smilde Dini , Schoon Yvonne , van der Velde Nathalie , Polinder Suzanne
Published: March 2019

We aimed to describe and evaluate the implementation of a home-based exercise program among community-dwelling adults aged ≥65 years. In an observational study, the twelve-week program was implemented in a community setting. The implementation plan consisted of dialogues with healthcare professionals and older adults, development of an implementation protocol, recruitment of participants, program implementation, and implementation evaluation. The dialogues consisted of a Delphi survey among healthcare professionals, and of individual and group meetings among older adults. The implementation of the program was evaluated using the framework model RE-AIM. In the dialogues with healthcare professionals and older adults, it was found that negative consequences of a fall and positive effects of preventing a fall should be emphasized to older adults, in order to get them engaged in fall prevention activities. A total of 450 older adults enrolled in the study, of which 238 started the program. The process evaluation showed that the majority of older adults were recruited by a community nurse. Also, a good collaboration between the research team and the local primary healthcare providers was accomplished, which was important in the recruitment. Future fall prevention studies may use this information in order to translate an intervention in a research project into a community-based program.
Fine Particulate Matter and Respiratory Healthcare Encounters among Survivors of Childhood Cancers
Authors: Ou Judy Y. , Hanson Heidi A. , Ramsay Joemy M. , Leiser Claire L. , Zhang Yue , VanDerslice James A. , Pope C. Arden , Kirchhoff Anne C.
Published: March 2019

Some chemotherapies that treat childhood cancers have pulmonary-toxic properties that increase risk for adverse respiratory-health outcomes. PM2.5 causes similar outcomes but its effect among pulmonary compromised cancer survivors is unknown. This case-crossover study identified the PM2.5-associated odds for primary-respiratory hospitalizations and emergency department visits among childhood cancer survivors in Utah. We compared risk among chemotherapy-treated survivors to a cancer-free sample. We calculated 3-day-average PM2.5 by ZIP code and county for event and control days. Conditional logistic regression estimated odds ratios. Models were stratified by cause of admission (infection, respiratory disease, asthma), previous chemotherapy, National Ambient Air Quality Standard (NAAQS), and other variables. Results are presented per 10 µg/m3 of PM2.5. 90% of events occurred at 3-day PM2.5 averages <35.4 µg/m3, the NAAQS 24-h standard. For survivors, PM2.5 was associated with respiratory hospitalizations (OR = 1.84, 95% CI = 1.13–3.00) and hospitalizations from respiratory infection (OR = 2.09, 95% CI = 1.06–4.14). Among chemotherapy-treated survivors, the PM2.5-associated odds of respiratory hospitalization (OR = 2.03, 95% CI = 1.14–3.61) were significantly higher than the cancer-free sample (OR = 0.84, 95% CI = 0.57–1.25). This is the first study to report significant associations between PM2.5 and respiratory healthcare encounters in childhood cancer survivors. Chemotherapy-treated survivors displayed the highest odds of hospitalization due to PM2.5 exposure and their risk is significantly higher than a cancer-free sample.
Development of A Safety Climate Scale for Geological Prospecting Projects in China
Authors: Wu Xiang , Gao Jingqi , Li Yuanlong , Wu Chunlin
Published: March 2019

The geological prospecting industry has developed rapidly in China over the past few years. It has made outstanding contributions to the discovery of new mineral resources, new energy sources, and the excavation and utilization of resources. However, geological prospecting projects do not have effective safety management measures at present. Moreover, the geological prospecting project has its own traits and features that differ from other industries, leading to the fact that safety management measures in other industries cannot be used in geological prospecting projects. Therefore, development of an effective safety management measuring tool is urgent and necessary. In recent years, safety climate has drawn great attention from scholars, and research results have been successfully applied in construction, coal mining and other industries. Based on the extensive literature review on safety climate as well as its organizational structure and employees’ individual behavior characteristics, this paper first extracted the factor structure of the safety climate and then developed a safety climate scale for geological prospecting projects. This paper used the methods of exploratory factor analysis and reliability analysis to ensure the developed safety climate scale was valid and reliable. The safety climate scale developed has four dimensions, i.e., project leader’s safety commitment, safety institutions, risk response, and employee’s safety attitude, containing a total of 17 measurable items. This study contributes to the current literature by exploring the factor structure of the safety climate for geological prospecting projects, and further provides a scientific basis for improvements in the geological prospecting industry. Meanwhile, the findings not only provide technical support for investigating and analyzing the safety management levels of the geological prospecting industry, but also contribute to the benchmarking standards among different enterprises and projects.
Dot Symbol Auto-Filling Method for Complex Areas Considering Shape Features
Authors: Yin Yong , Li Chengming , Wu Pengda
Published: March 2019

Filling dot maps with a regular pattern is a key step in visual representation of land use data. The traditional methods cannot adapt well to shape features of complex areas, leading to an unreasonable symbol arrangement in the inner region and area boundaries during symbol filling. For this reason, a dot symbol auto-filling method of complex areas considering shape features is proposed in this paper. First, based on the constrained Delaunay triangulation, the internal structure of a complex area is divided into three simple filling areas denoted tile type, narrow type, and point type. Next, according to the geometric shape features, these three type areas are filled with plane, line, and point level of symbols respectively. Finally, the dot symbols near to boundaries are adjusted on the basis of the boundary constraint to optimize the symbol-filling effect. Based on the national data of a region in Guizhou Province, the method proposed in this paper is compared to the traditional symbol filling methods for validation. The experimental results show that the proposed method improves the dot symbol sufficiency of complex areas, and the edge of dot symbol group closely adhere to the boundary and conform to the extension characteristics of boundary without creating spatial conflicts such as spatial overlap, the filling result can better reflect the shape features of the areas.
Regulators of Rho GTPases in the Nervous System: Molecular Implication in Axon Guidance and Neurological Disorders
Authors: Niftullayev Sadig , Lamarche-Vane Nathalie
Published: March 2019

One of the fundamental steps during development of the nervous system is the formation of proper connections between neurons and their target cells—a process called neural wiring, failure of which causes neurological disorders ranging from autism to Down’s syndrome. Axons navigate through the complex environment of a developing embryo toward their targets, which can be far away from their cell bodies. Successful implementation of neuronal wiring, which is crucial for fulfillment of all behavioral functions, is achieved through an intimate interplay between axon guidance and neural activity. In this review, our focus will be on axon pathfinding and the implication of some of its downstream molecular components in neurological disorders. More precisely, we will talk about axon guidance and the molecules implicated in this process. After, we will briefly review the Rho family of small GTPases, their regulators, and their involvement in downstream signaling pathways of the axon guidance cues/receptor complexes. We will then proceed to the final and main part of this review, where we will thoroughly comment on the implication of the regulators for Rho GTPases—GEFs (Guanine nucleotide Exchange Factors) and GAPs (GTPase-activating Proteins)—in neurological diseases and disorders.
Neuromuscular Plasticity in a Mouse Neurotoxic Model of Spinal Motoneuronal Loss
Authors: Gulino Rosario , Vicario Nunzio , Giunta Maria A.S. , Spoto Graziana , Calabrese Giovanna , Vecchio Michele , Gulisano Massimo , Leanza Giampiero , Parenti Rosalba
Published: March 2019

Despite the relevant research efforts, the causes of amyotrophic lateral sclerosis (ALS) are still unknown and no effective cure is available. Many authors suggest that ALS is a multi-system disease caused by a network failure instead of a cell-autonomous pathology restricted to motoneurons. Although motoneuronal loss is the critical hallmark of ALS given their specific vulnerability, other cell populations, including muscle and glial cells, are involved in disease onset and progression, but unraveling their specific role and crosstalk requires further investigation. In particular, little is known about the plastic changes of the degenerating motor system. These spontaneous compensatory processes are unable to halt the disease progression, but their elucidation and possible use as a therapeutic target represents an important aim of ALS research. Genetic animal models of disease represent useful tools to validate proven hypotheses or to test potential therapies, and the conception of novel hypotheses about ALS causes or the study of pathogenic mechanisms may be advantaged by the use of relatively simple in vivo models recapitulating specific aspects of the disease, thus avoiding the inclusion of too many confounding factors in an experimental setting. Here, we used a neurotoxic model of spinal motoneuron depletion induced by injection of cholera toxin-B saporin in the gastrocnemius muscle to investigate the possible occurrence of compensatory changes in both the muscle and spinal cord. The results showed that, following the lesion, the skeletal muscle became atrophic and displayed electromyographic activity similar to that observed in ALS patients. Moreover, the changes in muscle fiber morphology were different from that observed in ALS models, thus suggesting that some muscular effects of disease may be primary effects instead of being simply caused by denervation. Notably, we found plastic changes in the surviving motoneurons that can produce a functional restoration probably similar to the compensatory changes occurring in disease. These changes could be at least partially driven by glutamatergic signaling, and astrocytes contacting the surviving motoneurons may support this process.
Associations between Adipokines in Arthritic Disease and Implications for Obesity
Authors: MᵃᶜDonald Iona J. , Liu Shan-Chi , Huang Chien-Chung , Kuo Shu-Jui , Tsai Chun-Hao , Tang Chih-Hsin
Published: March 2019

Secretion from adipose tissue of adipokines or adipocytokines, comprising of bioactive peptides or proteins, immune molecules and inflammatory mediators, exert critical roles in inflammatory arthritis and obesity. This review considers the evidence generated over the last decade regarding the effects of several adipokines including leptin, adiponectin, visfatin, resistin, chemerin and apelin, in cartilage and bone homeostasis in the pathogenesis of rheumatoid arthritis and osteoarthritis, which has important implications for obesity.
Placenta Transcriptome Profiling in Intrauterine Growth Restriction (IUGR)
Authors: Majewska Marta , Lipka Aleksandra , Paukszto Lukasz , Jastrzebski Jan Pawel , Szeszko Karol , Gowkielewicz Marek , Lepiarczyk Ewa , Jozwik Marcin , Majewski Mariusz Krzysztof
Published: March 2019

Intrauterine growth restriction (IUGR) is a serious pathological complication associated with compromised fetal development during pregnancy. The aim of the study was to broaden knowledge about the transcriptomic complexity of the human placenta by identifying genes potentially involved in IUGR pathophysiology. RNA-Seq data were used to profile protein-coding genes, detect alternative splicing events (AS), single nucleotide variant (SNV) calling, and RNA editing sites prediction in IUGR-affected placental transcriptome. The applied methodology enabled detection of 37,501 transcriptionally active regions and the selection of 28 differentially-expressed genes (DEGs), among them 10 were upregulated and 18 downregulated in IUGR-affected placentas. Functional enrichment annotation indicated that most of the DEGs were implicated in the processes of inflammation and immune disorders related to IUGR and preeclampsia. Additionally, we revealed that some genes (S100A13, GPR126, CTRP1, and TFPI) involved in the alternation of splicing events were mainly implicated in angiogenic-related processes. Significant SNVs were overlapped with 6533 transcripts and assigned to 2386 coding sequence (CDS), 1528 introns, 345 5’ untranslated region (UTR), 1260 3’UTR, 918 non-coding RNA (ncRNA), and 10 intergenic regions. Within CDS regions, 543 missense substitutions with functional effects were recognized. Two known mutations (rs4575, synonymous; rs3817, on the downstream region) were detected within the range of AS and DEG candidates: PA28β and PINLYP, respectively. Novel genes that are dysregulated in IUGR were detected in the current research. Investigating genes underlying the IUGR is crucial for identification of mechanisms regulating placental development during a complicated pregnancy.
Are There New Biomarkers in Tissue and Liquid Biopsies for the Early Detection of Non-Small Cell Lung Cancer?
Authors: Calabrese Fiorella , Lunardi Francesca , Pezzuto Federica , Fortarezza Francesco , Vuljan Stefania Edith , Marquette Charles , Hofman Paul
Published: March 2019

Lung cancer is one of the most lethal malignancies worldwide, mainly due to its late diagnoses. The detection of molecular markers on samples provided from routine bronchoscopy including several liquid-based cytology tests (e.g., bronchoaspirate, bronchoalveolar lavage) and/or on easily obtained specimens such as sputum could represent a new approach to improve the sensitivity in lung cancer diagnoses. Recently growing interest has been reported for “noninvasive” liquid biopsy as a valuable source for molecular profiling. Unfortunately, a biomarker and/or composition of biomarkers capable of detecting early-stage lung cancer has yet to be discovered even if in the last few years there has been, through the use of revolutionary new technologies, an explosion of lung cancer biomarkers. Assay sensitivity and specificity need to be improved particularly when new approaches and/or tools are used. We have focused on the most important markers detected in tissue, and on several cytological specimens and liquid biopsies overall.
Microstructure and Thermal Insulation Property of Silica Composite Aerogel
Authors: Shang Lei , Lyu Yang , Han Wenbo
Published: March 2019

Tetraethyl orthosilicate was selected as a matrix of heat insulating materials among three silanes, and an anti-infrared radiation fiber was chosen as a reinforcement for silica aerogel insulation composite. The silica aerogel was combined well and evenly distributed in the anti-infrared radiation fiber. The heat insulation effect was improved with the increase in thickness of the aerogel insulation material, as determined by the self-made aerospace insulation material insulation performance test equipment. The 15 mm and 30 mm thick thermal insulation material heated at 250 °C for 3 h, the temperatures at the cold surface were about 80 °C and 60 °C, respectively, and the temperatures at 150 mm above the cold surface were less than 60 °C and 50 °C, respectively. The silica aerogel composites with various thicknesses showed good thermal insulation stability. The silica insulation composite with a thickness of 15 mm exhibited good heat insulation performance, meets the thermal insulation requirements of general equipment compartments under low-temperature and long-term environmental conditions. The thermal conductivity of prepared silica aerogel composite was 0.0191 W·m−1·k−1 at room temperature and 0.0489 W·m−1·k−1 at 500 °C.
Evaluating the Quality Surface Performance of Additive Manufacturing Systems: Methodology and a Material Jetting Case Study
Authors: Udroiu Razvan , Braga Ion Cristian , Nedelcu Anisor
Published: March 2019

The performance characterization of the manufacturing processes for additive manufacturing (AM) systems is a significant task for their standardization and implementation in the industry. Also, there is a large diversity of materials used in different AM processes. In the present paper, a methodology is proposed to evaluate, in different directions, the performance of an AM process and material characterization in terms of surface quality. This methodology consists of eight steps, based on a new surface inspection artifact and basic artifact orientations. The proposed artifact with several design configurations fits different AM systems sizes and meets the needs of customers. The effects of main factors on the surface roughness of up-facing platens of the artifacts are investigated using the statistical design of experiments. The proposed methodology is validated by a case study focused on PolyJet material jetting technology. Samples are manufactured of photopolymer resins and post-processed. Three factors (i.e., artifact orientation, platen orientation, and finish type) are considered for the investigation. The case study results show that the platen orientation, finish type, and their interaction have a significant influence on the surface roughness (Ra). The best Ra roughness results were obtained for the glossy finish type in the range of 0.5–4 μm.
Ternary Blended Binder for Production of a Novel Type of Lightweight Repair Mortar
Authors: Pavlíková Milena , Zemanová Lucie , Záleská Martina , Pokorný Jaroslav , Lojka Michal , Jankovský Ondřej , Pavlík Zbyšek
Published: March 2019

The goal of the paper was development and testing of a novel type of ternary blended binder based on lime hydrate, metakaolin, and biomass ash that was studied as a binding material for production of lightweight mortar for renovation purposes. The biomass ash used as one of binder components was coming from wood chips ash combustion in a biomass heating plant. The raw ash was mechanically activated by grinding. In mortar composition, wood chips ash and metakaolin were used as partial substitutes of lime hydrate. Silica sand of particle size fraction 0–2 mm was mixed from three normalized sand fractions. For the evaluation of the effect of biomass ash and metakaolin incorporation in mortar mix on material properties, reference lime mortar was tested as well. Among the basic physical characterization of biomass ash, metakaolin and lime hydrate, specific density, specific surface, and particle size distribution were assessed. Their chemical composition was measured by X-Ray fluorescence analysis (XRF), morphology was examined using scanning electron microscopy (SEM), elements mapping was performed using energy dispersive spectroscopy (EDS) analyser, and mineralogical composition was tested using X-Ray diffraction (XRD). For the developed mortars, set of structural, mechanical, hygric, and thermal properties was assessed. The mortars with ternary blended binder exhibited improved mechanical resistance, lower thermal conductivity, and increased water vapor permeability compared to the reference lime mortar. Based on good functional performance of the produced mortar, the tested biomass ash could potentially represent a novel sustainable alternative to other pozzolans commonly used in construction industry. Moreover, reuse of biomass ash in production of building materials is highly beneficial both from the environmental and economic reasons especially taking into account circular economy principles. The ternary blended binder examined in this paper can find use in both rendering and walling repair mortars meeting the requirements of culture heritage authorities and technical standards.
Investigations of Machining Characteristics in the Upgraded MQL-Assisted Turning of Pure Titanium Alloys Using Evolutionary Algorithms
Authors: Singh Gurraj , Pruncu Catalin Iulian , Gupta Munish Kumar , Mia Mozammel , Khan Aqib Mashood , Jamil Muhammad , Pimenov Danil Yurievich , Sen Binayak , Sharma Vishal S.
Published: March 2019

Environmental protection is the major concern of any form of manufacturing industry today. As focus has shifted towards sustainable cooling strategies, minimum quantity lubrication (MQL) has proven its usefulness. The current survey intends to make the MQL strategy more effective while improving its performance. A Ranque–Hilsch vortex tube (RHVT) was implemented into the MQL process in order to enhance the performance of the manufacturing process. The RHVT is a device that allows for separating the hot and cold air within the compressed air flows that come tangentially into the vortex chamber through the inlet nozzles. Turning tests with a unique combination of cooling technique were performed on titanium (Grade 2), where the effectiveness of the RHVT was evaluated. The surface quality measurements, forces values, and tool wear were carefully investigated. A combination of analysis of variance (ANOVA) and evolutionary techniques (particle swarm optimization (PSO), bacteria foraging optimization (BFO), and teaching learning-based optimization (TLBO)) was brought into use in order to analyze the influence of the process parameters. In the end, an appropriate correlation between PSO, BFO, and TLBO was investigated. It was shown that RHVT improved the results by nearly 15% for all of the responses, while the TLBO technique was found to be the best optimization technique, with an average time of 1.09 s and a success rate of 90%.
Cayley Inclusion Problem Involving XOR-Operation
Authors: Ali Imran , Ahmad Rais , Wen Ching-Feng
Published: March 2019

In this paper, we study an absolutely new problem, namely, the Cayley inclusion problem which involves the Cayley operator and a multi-valued mapping with XOR-operation. We have shown that the Cayley operator is a single-valued comparison and it is Lipschitz-type-continuous. A fixed point formulation of the Cayley inclusion problem is shown by using the concept of a resolvent operator as well as the Yosida approximation operator. Finally, an existence and convergence result is proved. An example is constructed for some of the concepts used in this work.
Some Applications of Eigenvalue Problems for Tensor and Tensor–Block Matrices for Mathematical Modeling of Micropolar Thin Bodies
Authors: Nikabadze Mikhail , Ulukhanyan Armine
Published: March 2019

The statement of the eigenvalue problem for a tensor–block matrix (TBM) of any order and of any even rank is formulated, and also some of its special cases are considered. In particular, using the canonical presentation of the TBM of the tensor of elastic modules of the micropolar theory, in the canonical form the specific deformation energy and the constitutive relations are written. With the help of the introduced TBM operator, the equations of motion of a micropolar arbitrarily anisotropic medium are written, and also the boundary conditions are written down by means of the introduced TBM operator of the stress and the couple stress vectors. The formulations of initial-boundary value problems in these terms for an arbitrary anisotropic medium are given. The questions on the decomposition of initial-boundary value problems of elasticity and thin body theory for some anisotropic media are considered. In particular, the initial-boundary problems of the micropolar (classical) theory of elasticity are presented with the help of the introduced TBM operators (tensors–operators). In the case of an isotropic micropolar elastic medium (isotropic and transversely isotropic classical media), the TBM operator (tensors–operators) of cofactors to TBM operators (tensors–tensors) of the initial-boundary value problems are constructed that allow decomposing initial-boundary value problems. We also find the determinant and the tensor of cofactors to the sum of six tensors used for decomposition of initial-boundary value problems. From three-dimensional decomposed initial-boundary value problems, the corresponding decomposed initial-boundary value problems for the theories of thin bodies are obtained.
Spiralyde A, an Antikinetoplastid Dolabellane from the Brown Alga Dictyota spiralis
Authors: Chiboub Olfa , Sifaoui Ines , Lorenzo-Morales Jacob , Abderrabba Manef , Mejri Mondher , Fernández José Javier , Piñero José E. , Díaz-Marrero Ana R.
Published: March 2019

Bioassay-guided fractionation of the antikinetoplastid extract of the brown alga Dictyota spiralis has led to the isolation of spiralyde A (1), a new dolabellane aldehyde, along with other five known related diterpenes (2–6). Their structures were determined by HRESIMS, 1D and 2D NMR spectroscopy, and comparison with data reported in the literature. The antiparasitic activity of all compounds was evaluated. Spiralyde A (1) and the known compound 3,4-epoxy-7,18-dolabelladiene (2) were the most active compounds against Leishmania amazonensis and Trypanosoma cruzi. Spiralyde A (1) was the most potent compound, comparable to benznidazole, the reference drug for trypanocidal activity.
Effects of Cerium on Weld Solidification Crack Sensitivity of 441 Ferritic Stainless Steel
Authors: Zhu Shuangchun , Yan Biao
Published: March 2019

The addition of rare earth element Ce in ferritic stainless steel can improve the high temperature performance to meet the service requirements of automobile exhaust systems at high temperatures. Automobile exhaust systems are generally applied as welded pipes, so it is necessary to study the effect of Ce on the weldability of ferritic stainless steel. In this study, the Trans-varestraint test method was used to test the solidification crack sensitivities of 441 and 441Ce ferritic stainless steel. The 441Ce steel, which has added Ce, showed poor resistance to weld solidification cracking. Using Thermo-Calc software, Ce was observed to expand the solidification temperature range of 441 ferritic stainless steel, increase the time for solid–liquid coexistence during solidification, and increase the sensitivity of solidification cracking. Further, from scanning electron microscopy and energy dispersive spectrometer analysis, the addition of Ce was found to reduce high temperature precipitation (Ti,Nb)(C,N), reduce or even eliminate the “pinning” effect during solidification, and increase solidification crack sensitivity of 441 ferritic stainless steel.
Strategy to Enhance Magnetic Properties of Fe78Si9B13 Amorphous Powder Cores in the Industrial Condition
Authors: Sun Haibo , Wang Ce , Chen Weihong , Lin Jiexin
Published: March 2019

In this study, the soft magnetic properties of Fe78Si9B13 amorphous magnetic powder cores (AMPCs) were enhanced by coordinately adjusting the technological parameters, including the particle size distribution, molding pressure, and coating agent content, in the industrial condition. The results show that the optimized comprehensive soft magnetic properties of the Fe78Si9B13 AMPCs could be obtained under the following process conditions: (1) the distribution of particle size is 20 wt.% for 140–170 mesh, 70 wt.% for 170–270 mesh, and 10 wt.% for 270–400 mesh; (2) the molding pressure is in the range of 2.35–2.45 GPa; and (3) the additive amount of sodium silicate is 1.5 wt.%. After the collaborative optimization, the AMPCs’ compact density, ρ, the effective permeability, μe, and the residual effective permeability at the applied magnetizing field of 7.96 kA/m, μe@7.96 kA/m, increased from 5.61 g/cm3 to 5.86 g/cm3, from 58.13 to 77.01, and from 40.36 to 49.57, respectively. The attenuation ratio of the effective permeability, when in the frequency band of 20–100 kHz, was less than 0.85%. The core loss at the 50 kHz for the maximum magnetic flux density of 0.1 T reduced from 380.85 mW/cm3 to 335.23 mW/cm3. This work will encourage the further application of Fe-based AMPCs in the fields of electronics and telecommunication.
Three-Dimensionally Structured Flexible Fog Harvesting Surfaces Inspired by Namib Desert Beetles
Authors: Park Jun , Kim Seok
Published: March 2019

Fog harvesting of the Namib desert beetles has inspired many researchers to design artificial fog harvesting hybrid surfaces, which commonly involve flat hydrophilic patterns on hydrophobic surfaces. However, relatively less interest has been shown in the bumpy topography of the Namib desert beetle’s dorsal surface as well as its curved body shape when designing artificial hybrid surfaces. In this work, we explore a fog harvesting flexible hybrid surface that has a superhydrophilic 3D copper oxide pattern on a hydrophobic rough elastomer background surface enabled by transferring a copper layer from a prepared donor substrate to a receiving elastomer substrate. The water collection rates of the hybrid surface and control samples are measured, and the results reveal the advantages of 3D bumpy structures on a curved shape surface to facilitate fog harvesting, particularly in more unfavorable fog stream conditions. The curved 3D bumpy hybrid surface exhibits an over 16 times higher water collection rate than the flat 2D hybrid surface in the fog stream in parallel to the hybrid surface. This work provides an improved understanding of the role of the Namib desert beetle’s bumpy dorsal surface and curved body shape, and offers an insight into the design of novel surfaces with enhanced fog harvesting performance.
Development of the Troponin Detection System Based on the Nanostructure
Authors: Lee Taek , Ahn Jae-Hyuk , Choi Jinha , Lee Yeonju , Kim Jin-Myung , Park Chulhwan , Jang Hongje , Kim Tae-Hyung , Lee Min-Ho
Published: March 2019

During the last 30 years, the World Health Organization (WHO) reported a gradual increase in the number of patients with cardiovascular disease (CVD), not only in developed but also in developing countries. In particular, acute myocardial infarction (AMI) is one of the severe CVDs because of the high death rate, damage to the body, and various complications. During these harmful effects, rapid diagnosis of AMI is key for saving patients with CVD in an emergency. The prompt diagnosis and proper treatment of patients with AMI are important to increase the survival rate of these patients. To treat patients with AMI quickly, detection of a CVD biomarker at an ultra-low concentration is essential. Cardiac troponins (cTNs), cardiac myoglobin (cMB), and creatine kinase MB are typical biomarkers for AMI detection. An increase in the levels of those biomarkers in blood implies damage to cardiomyocytes and thus is related to AMI progression. In particular, cTNs are regarded as a gold standard biomarker for AMI diagnosis. The conventional TN detection system for detection of AMI requires long measurement time and is labor-intensive and tedious. Therefore, the demand for sensitive and selective TN detection techniques is increasing at present. To meet this demand, several approaches and methods have been applied to develop a TN detection system based on a nanostructure. In the present review, the authors reviewed recent advances in TN biosensors with a focus on four detection systems: (1) An electrochemical (EC) TN nanobiosensor, (2) field effect transistor (FET)-based TN nanobiosensor, (3) surface plasmon resonance (SPR)-based TN nanobiosensor and (4) surface enhanced Raman spectroscopy (SERS)-based TN nanobiosensor.
Mechanophenotyping of B16 Melanoma Cell Variants for the Assessment of the Efficacy of (-)-Epigallocatechin Gallate Treatment Using a Tapered Microfluidic Device
Authors: Nakamura Masanori , Ono Daichi , Sugita Shukei
Published: March 2019

Metastatic cancer cells are known to have a smaller cell stiffness than healthy cells because the small stiffness is beneficial for passing through the extracellular matrix when the cancer cells instigate a metastatic process. Here we developed a simple and handy microfluidic system to assess metastatic capacity of the cancer cells from a mechanical point of view. A tapered microchannel was devised through which a cell was compressed while passing. Two metastasis B16 melanoma variants (B16-F1 and B16-F10) were examined. The shape recovery process of the cell from a compressed state was evaluated with the Kelvin–Voigt model. The results demonstrated that the B16-F10 cells showed a larger time constant of shape recovery than B16-F1 cells, although no significant difference in the initial strain was observed between B16-F1 cells and B16-F10 cells. We further investigated effects of catechin on the cell deformability and found that the deformability of B16-F10 cells was significantly decreased and became equivalent to that of untreated B16-F1 cells. These results addressed the utility of the present system to handily but roughly assess the metastatic capacity of cancer cells and to investigate drug efficacy on the metastatic capacity.
Process Understanding of Plasma Electrolytic Polishing through Multiphysics Simulation and Inline Metrology
Authors: Danilov Igor , Hackert-Oschätzchen Matthias , Zinecker Mike , Meichsner Gunnar , Edelmann Jan , Schubert Andreas
Published: March 2019

Currently, the demand for surface treatment methods like plasma electrolytic polishing (PeP)—a special case of electrochemical machining—is increasing. This paper provides a literature review on the fundamental mechanisms of the plasma electrolytic polishing process and discusses simulated and experimental results. The simulation shows and describes a modelling approach of the polishing effect during the PeP process. Based on the simulation results, it can be assumed that PeP can be simulated as an electrochemical machining process and that the simulation can be used for roughness and processing time predictions. The simulation results exhibit correlations with the experimentally-achieved approximation for roughness decrease. The experimental part demonstrates the results of the PeP processing for different times. The results for different types of roughness show that roughness decreases exponentially. Additionally, a current efficiency calculation was made. Based on the experimental results, it can be assumed that PeP is a special electrochemical machining process with low passivation.
Effect of Stereochemical Configuration on the Transport and Metabolism of Catechins from Green Tea across Caco-2 Monolayers
Authors: Ai Zeyi , Liu Shuyuan , Qu Fengfeng , Zhang Haojie , Chen Yuqiong , Ni Dejiang
Published: March 2019

The transcellular transport and metabolism of eight green tea catechins (GTCs) were studied in Caco-2 monolayers, with the aim of investigating the effect of cis–trans isomerism on the membrane permeability and biotransformation of GTCs. The results showed that the catechin stereochemistry significantly affects the efflux transport rather than the absorption transport in the Caco-2 monolayers. The trans catechins showed a better transcellular permeability than their corresponding cis (epi) catechins in the efflux transport, as the efflux amount of trans catechins were all significantly higher than that of the cis (epi) catechins at each concentration and each time point tested. Moreover, the relative contents of the (+)-catechin (C)-O-sulfate, (+)-gallocatechin (GC)-O-sulfate, (−)-catechin gallate (CG)-O-sulfate, and (−)-gallocatechin gallate (GCG)-O-sulfate in the efflux transport were 2.67, 16.08, 50.48, and 31.54 times higher than that of the (−)-epicatechin (EC)-O-sulfate, (−)-epigallocatechin (EGC)-O-sulfate, (−)-epicatechin gallate (ECG)-O-sulfate, and (−)-epigallocatechin gallate (EGCG)-O-sulfate, respectively. It indicated that more metabolites were observed after the transcellular efflux of trans catechins. Furthermore, after two hours of incubation, the GTCs could significantly increase the expression of multidrug resistance-associated protein 2 (MRP2) and breast cancer-resistance protein (BCRP), and decrease the expression of P-glycoprotein in the Caco-2 cells. The regulation of GTCs on P-glycoprotein, MRP2, and BCRP could also be significantly influenced by the chemical and dimensional structure. In a conclusion, catechin stereochemistry significantly affects the transport and metabolism of GTCs when refluxed in the Caco-2 monolayers.
Cartographic Visualization for Indoor Semantic Wayfinding
Authors: Bakogiannis Nikolaos , Gkonos Charalampos , Hurni Lorenz
Published: March 2019

In recent years, pedestrian navigation assistance has been used by an increasing number of people to support wayfinding tasks. Especially in unfamiliar and complex indoor environments such as universities and hospitals, the importance of an effective navigation assistance becomes apparent. This paper investigates the feasibility of the indoor landmark navigation model (ILNM), a method for generating landmark-based routing instructions, by combining it with indoor route maps and conducting a wayfinding experiment with human participants. Within this context, three different cartographic visualization scenarios were designed and evaluated. Two of these scenarios were based on the implementation of the ILNM algorithm, with the concurrent effort to overcome the challenge of representing the semantic navigation instructions in two different ways. In the first scenario, the selected landmarks were visualized as pictograms, while in the second scenario, an axonometric-based design philosophy for the depiction of landmarks was followed. The third scenario was based on the benchmark approach (metric-based routing instructions) for conveying routing instructions to the users. The experiment showed that the implementation of the ILNM was feasible, and, more importantly, it was beneficial in terms of participants’ navigation performance during the wayfinding experiment, compared to the metric-based instructions scenario (benchmark for indoor navigation). Valuable results were also obtained, concerning the most suitable cartographic approach for visualizing the selected landmarks, while implementing this specific algorithm (ILNM). Finally, our findings confirm that the existence of landmarks, not only within the routing instructions, but also as cartographic representations on the route map itself, can significantly help users to position themselves correctly within an unfamiliar environment and to improve their navigation performance.
Impact of Chemical Post-Processing in Fused Deposition Modelling (FDM) on Polylactic Acid (PLA) Surface Quality and Structure
Authors: Valerga Ana P. , Batista Moises , Fernandez-Vidal Severo R. , Gamez Antonio J.
Published: March 2019

The application of techniques to improve the surface finish of pieces obtained by fused deposition modelling, as well as other functional aspects, is of great interest nowadays. Polylactic acid, a biodegradable material, has been considered a possible substitute for petroleum-based polymers. In this work, different chemical post-processing methods are applied to polylactic acid pieces obtained by fused deposition modelling and some characteristics are studied. Structural, thermal, and crystallinity property changes are analyzed according to the treatments applied. This can prevent degradation, eliminate the glass transition phase of the material, and thereby increase the thermal resistance by about 50 °C. An improvement in the roughness of the pieces of up to 97% was also found.
Formulation and Characterization of a SIS-Based Photocrosslinkable Bioink
Authors: Serna Julian A. , Florez Sergio Leonardo , Talero Vivian A. , Briceño Juan C. , Muñoz-Camargo Carolina , Cruz Juan C.
Published: March 2019

Decellularized extracellular matrices (dECMs) represent a promising alternative as a source of materials to develop scaffolds that closely mimic the native environment of cells. As a result, dECMs have attracted significant attention for their applications in regenerative medicine and tissue engineering. One such application is 3D bioprinting, in which dECMs can be used to prepare bioinks with the biomimicry attributes required for regeneration purposes. Formulating bioinks is, however, challenging, due to difficulties in assuring that the printed materials match the mechanical properties of the tissue which is to be regenerated. To tackle this issue, a number of strategies have been devised, including crosslinking methods, the addition of synthetic materials as excipients, and the use of synthetic matrices for casting. We are particularly interested in extrusion-based 3D bioprinting, mainly due to the ease of rapidly conducting tests for adjusting operating conditions such that the required rheological and mechanical properties are met when using it. Here, we propose a novel bioink that consists of an acid-based precipitation of a small intestinal submucosa (SIS) dECM. The formulated bioink also relies on photocrosslinking reactions to attempt to control gelation and ultimately the mechanical properties of the extruded material. Photoinitiation was explored with the aid of varying concentrations of riboflavin (RF). Manual extrusion and rheological flow tests confirmed the printability and shear-thinning behavior of all formulations. Photocrosslinking reactions, however, failed to promote a substantial increase in gelation, which was attributed to considerable entanglement of undigested collagen molecules. As a result, pendant amine groups thought to be involved in the photo-mediated reactions remain largely inaccessible. In silico computational fluid dynamics (CFD) simulations were implemented to determine shear stress values on the bioink along the exit of the printing nozzle. Moreover, we calculated a stability parameter as a means to estimate changes in the bioink stability during the extrusion process. Future studies should be directed toward assessing the role of temperature-induced gelation in the rheological properties of the bioink and the development of strategies to improve the efficiency of photocrosslinking processes.