bluuebunny/crossref_metadata_2025 huggingface dataset:
Recurrent HBV Integration Targets as Potential Drivers in Hepatocellular Carcinoma
Authors: Lin Selena Y. , Zhang Adam , Lian Jessica , Wang Jeremy , Chang Ting-Tsung , Lin Yih-Jyh , Song Wei , Su Ying-Hsiu
Published: May 2021

Chronic hepatitis B virus (HBV) infection is the major etiology of hepatocellular carcinoma (HCC), frequently with HBV integrating into the host genome. HBV integration, found in 85% of HBV-associated HCC (HBV–HCC) tissue samples, has been suggested to be oncogenic. Here, we investigated the potential of HBV–HCC driver identification via the characterization of recurrently targeted genes (RTGs). A total of 18,596 HBV integration sites from our in-house study and others were analyzed. RTGs were identified by applying three criteria: at least two HCC subjects, reported by at least two studies, and the number of reporting studies. A total of 396 RTGs were identified. Among the 28 most frequent RTGs, defined as affected in at least 10 HCC patients, 23 (82%) were associated with carcinogenesis and 5 (18%) had no known function. Available breakpoint positions from the three most frequent RTGs, TERT, MLL4/KMT2B, and PLEKHG4B, were analyzed. Mutual exclusivity of TERT promoter mutation and HBV integration into TERT was observed. We present an RTG consensus through comprehensive analysis to enable the potential identification and discovery of HCC drivers for drug development and disease management.
Co-Adaptation of Physical Attributes of the Mammalian Female Reproductive Tract and Sperm to Facilitate Fertilization
Authors: Tung Chih-Kuan , Suarez Susan S.
Published: May 2021

The functions of the female reproductive tract not only encompass sperm migration, storage, and fertilization, but also support the transport and development of the fertilized egg through to the birth of offspring. Further, because the tract is open to the external environment, it must also provide protection against invasive pathogens. In biophysics, sperm are considered “pusher microswimmers”, because they are propelled by pushing fluid behind them. This type of swimming by motile microorganisms promotes the tendency to swim along walls and upstream in gentle fluid flows. Thus, the architecture of the walls of the female tract, and the gentle flows created by cilia, can guide sperm migration. The viscoelasticity of the fluids in the tract, such as mucus secretions, also promotes the cooperative swimming of sperm that can improve fertilization success; at the same time, the mucus can also impede the invasion of pathogens. This review is focused on how the mammalian female reproductive tract and sperm interact physically to facilitate the movement of sperm to the site of fertilization. Knowledge of female/sperm interactions can not only explain how the female tract can physically guide sperm to the fertilization site, but can also be applied for the improvement of in vitro fertilization devices.
The Impact of Fixation on the Detection of Oligodendrocyte Precursor Cell Morphology and Vascular Associations
Authors: Pfeiffer Friederike , Sherafat Amin , Nishiyama Akiko
Published: May 2021

Oligodendrocyte precursor cells (OPCs) display numerous protrusions that extend into the surrounding parenchyma in the brain. Depending on the preparation of the tissue analyzed, these protrusions are more or less visible. We applied six different fixation methods and compared the effect of prolonged and stronger fixation on fluorescence intensity of platelet-derived growth factor receptor alpha, a surface marker of OPCs. Importantly, the fluorescence signal is mostly lost on protrusions as compared to the cell body, which has to be considered for specific analyses. Additionally, we show numerous contacts established between OPCs and the brain vasculature, which will contribute to the understanding of the interactions between these two elements.
Extracellular Matrix Components Regulate Bone Sialoprotein Expression in MDA-MB-231 Breast Cancer Cells
Authors: Keller Florian , Bruch Roman , Clauder Franziska , Hafner Mathias , Rudolf Rüdiger
Published: May 2021

Bone sialoprotein (BSP) has become a target in breast cancer research as it is associated with tumor progression and metastasis. The mechanisms underlying the regulation of BSP expression have been largely elusive. Given that BSP is involved in the homing of cancer cells in bone metastatic niches, we addressed regulatory effects of proteolytic cleavage and extracellular matrix components on BSP expression and distribution in cell culture models. Therefore, MDA-MB-231 human breast cancer cells were kept in 2D and 3D spheroid cultures and exposed to basement membrane extract in the presence or absence of matrix metalloproteinase 9 or the non-polar protease, dispase. Confocal imaging of immunofluorescence samples stained with different antibodies against human BSP demonstrated a strong inducing effect of basement membrane extract on anti-BSP immunofluorescence. Similarly, protease incubation led to acute upregulation of anti-BSP immunofluorescence signals, which was blocked by cycloheximide, suggesting de novo formation of BSP. In summary, our data show that extracellular matrix components play an important function in regulating BSP expression and hint at mechanisms for the formation of bone-associated metastasis in breast cancer that might involve local control of BSP levels by extracellular matrix degradation and release of growth factors.
Synthesis of Oxide Ceramics in Detonating Atmosphere
Authors: Gibot Pierre
Published: May 2021

A detonation process based on 2,4,6 trinitrotoluene (TNT), used as an energetic reagent, was successfully implemented in the synthesis of a series of metal oxide ceramics. TNT offers better physicochemical and mechanical properties than the energetic compounds traditionally used in such processes, thus offering safer handling and transport conditions. The experimental procedure, which consisted to of mixing the energetic molecule with a ceramic salt, was simple to perform. The detonation products were characterized by X-ray diffraction, scanning and transmission electron microscopies, energy dispersive X-ray spectroscopy and nitrogen physisorption. The as-synthesized ceramic powders (CeO2, HfO2, Nb2O5, and In2O3) were crystalline and made of nano-sized quasi-spherical particles. This investigation provides an enhanced detonation synthesis process for elaborating ceramics. The majority of the oxide materials mentioned in this study had never previously been prepared by the detonation process.
Oral Diseases and Quality of Life between Obese and Normal Weight Adolescents: A Two-Year Observational Study
Authors: Tengku H Tengku Nurfarhana Nadirah , Peh Wei Ying , Shoaib Lily Azura , Baharuddin Nor Adinar , Vaithilingam Rathna Devi , Saub Roslan
Published: May 2021

This study aimed to investigate the association between oral disease burden and oral health related quality of life (OHRQoL) among overweight/obese (OW/OB) and normal weight (NW) Malaysian adolescents. A total of 397 adolescents were involved in the two-year prospective observational cohort study. OHRQOL was measured through a self-administered questionnaire containing the short version of the Malaysian Oral Health Impact Profile (OHIP[M]). Body mass index (BMI) was used for anthropometric measurement. Whilst, decayed, missing, and filled teeth (DMFT) index, Significant Caries Index (SiC), simplified basic periodontal examination (S-BPE), and gingival bleeding index (GBI) were used for clinical assessment tools. Higher dental caries prevalence was observed in the NW group while higher SiC was reported in the OW/OB group. Regardless of the obesity status, the prevalence of gingivitis (BPE code 1 and 2) was high in this study. A reduction of GBI prevalence was observed in the two-year follow-up results with an increased prevalence of OHRQoL impact in the OW/OB group compared to the NW group (p > 0.05). The findings from this study suggested that obesity status did not have influence over the burden of oral diseases and OHRQoL. It offers insights referring to the changes in adolescents’ oral diseases burden and OHRQoL.
Microwave Absorption Properties of Fe3O4 Particles Coated with Al via Rotating Magnetic Field Method
Authors: Shorstkii Ivan , Sosnin Maxim
Published: May 2021

Soft magnetic composites (SMCs) of Fe3O4 particles coated with Al nanoparticles were prepared using the rotating magnetic field method, and the microwave absorption properties and microstructures of these composites were investigated. The results show that a well-distributed Al nanoparticles coating layer was formed on the surface of the Fe3O4 particles upon mechanical friction and rotating magnetic field distribution. Scanning electron microscopy and X-ray diffraction XRD studies show that the rotating magnetic field method can produce a uniform coating of the aluminium layer on the Fe3O4 particles. Compared with common composites from Fe3O4 particles, SMCs of Fe3O4(Al) particles have stronger magnetic loss behaviour and weaker dielectric loss ability, as well as good reflection characteristics over a wide frequency range. The minimum reflection loss (RL) is −16.2 dB at 12.0 GHz for a corresponding thickness of 5 mm obtained for SMCs of Fe3O4(Al) particles. The presented rotating magnetic field method used in the Fe3O4 particles coating process with Al nanoparticles has great potential in composite materials synthesis with different morphology and areas of application.
Millimeter-Wave Reflector Based on a Ferroelectric Material with Electrical Beam Steering
Authors: Platonov Roman , Altynnikov Andrey , Komlev Andrey , Sosunov Alexei , Kozyrev Andrey B.
Published: May 2021

Millimeter waves are increasingly used in modern telecommunication systems for wireless data transmission. However, higher path loss, especially caused by non-line-of-sight scenarios, remains challenging. The design of an electrically controllable reflector for the millimeter-wave range is elaborated and presented in this manuscript. The reflector design was based on distributed ferroelectric ceramic elements and could be used in a frequency range up to 100 GHz. The issue of the ferroelectric reflector impedance matching was analyzed in detail. Two possible implementations of the reflector for indoor and outdoor communication systems were considered and simulated. The prototype of the proposed reflector for an operating frequency of 60 GHz was manufactured. Both simulation and measurement results demonstrated the beam steering by the proposed ferroelectric reflector.
Effects of Recycled Fine Aggregates and Inorganic Crystalline Materials on the Strength and Pore Structures of Cement-Based Composites
Authors: Chen Sung-Ching , Zou Si-Yu , Hsu Hui-Mi
Published: May 2021

Concrete is porous; the partial pores in the internal structure of concrete are generated by hydration products, such as calcium hydroxide, dissolved in water. External harmful substances in the form of gases or aqueous solutions can penetrate concrete. The destruction of the internal structure of concrete leads to problems such as shortening of the service life of concrete as well as the corrosion and poor durability of steel. To improve the pore structure of concrete, a material can be added to concrete mixtures to cause the secondary hydration of the hydration products of cement. This reaction is expected to reduce the pore volume and increase the density of concrete. For existing concrete structures, inorganic crystalline materials can be used to protect the surface and reduce the intrusion of external harmful substances. In this study, the water–binder ratio was 0.4 and 0.6. Three inorganic crystalline materials and recycled fine aggregates (0%, 10%, 20%, and 30% replacement of natural aggregates by weight) were used in the same cement-based composites. The results indicated that all specimens had a high total charge-passed value, and inorganic crystalline material C provided superior protection for green cement-based composites.
Microstructure and Crystallographic Texture of Laser Additive Manufactured Nickel-Based Superalloys with Different Scanning Strategies
Authors: Liu Xingbo , Xiao Hui , Xiao Wenjia , Song Lijun
Published: May 2021

Control of solidification structure and crystallographic texture during metal additive manufacturing is a challenging work which attracts the increasing interest of researchers. In the present work, two kinds of scanning strategies (i.e., single-directional scanning (SDS) and cross-directional scanning (CDS) were used to control the solidification structure and crystallographic texture during quasi-continuous-wave laser additive manufacturing (QCW-LAM) of Inconel 718. The results show that the solidification structure and texture are strongly dependent on scanning strategies. The SDS develops a typical fiber texture with unidirectional columnar grains, whereas the CDS develops a more random texture with a mixture of unidirectional and multidirectional grains. In addition, the SDS promotes the continuously epitaxial growth of columnar dendrites and results in the linearly distributed Laves phase particles, while the CDS leads to the alternately distributed Laves phase particles with chain-like morphology and discrete morphology. The changed stacking features of molten-pool boundary and the switched heat flow direction caused by different scanning strategies plays a crucial role on the epitaxial growth of dendrites and the final solidification structure of the fabricated parts.
High-Efficiency Ho:YAP Pulse Laser Pumped at 1989 nm
Authors: Niu Chao , Jiang Yan , Wen Ya , Zhao Lu , Chen Xinyu , Wu Chunting , Dai Tongyu
Published: May 2021

A Tm:YAP laser with an output wavelength of 1989 nm was selected for the first time as the pump source of a Q-switched Ho:YAP laser. When the absorbed power was 30 W, an average power of 18.02 W with the pulse width of 104.2 ns acousto-optic (AO) Q-switched Ho:YAP laser was obtained at a repetition frequency of 10 kHz. The slope efficiency was 70.11%, and the optical-optical conversion efficiency was 43.03%. The output center wavelength was 2129.22 nm with the line width of 0.74 nm.
Metagenomics Analysis Reveals the Microbial Communities, Antimicrobial Resistance Gene Diversity and Potential Pathogen Transmission Risk of Two Different Landfills in China
Authors: Wan Shan , Xia Min , Tao Jie , Pang Yanjun , Yu Fugen , Wu Jun , Chen Shanping
Published: May 2021

In this study, we used a metagenomic approach to analyze microbial communities, antibiotic resistance gene diversity, and human pathogenic bacterium composition in two typical landfills in China. Results showed that the phyla Proteobacteria, Bacteroidetes, and Actinobacteria were predominant in the two landfills, and archaea and fungi were also detected. The genera Methanoculleus, Lysobacter, and Pseudomonas were predominantly present in all samples. sul2, sul1, tetX, and adeF were the four most abundant antibiotic resistance genes. Sixty-nine bacterial pathogens were identified from the two landfills, with Klebsiella pneumoniae, Bordetella pertussis, Pseudomonas aeruginosa, and Bacillus cereus as the major pathogenic microorganisms, indicating the existence of potential environmental risk in landfills. In addition, KEGG pathway analysis indicated the presence of antibiotic resistance genes typically associated with human antibiotic resistance bacterial strains. These results provide insights into the risk of pathogens in landfills, which is important for controlling the potential secondary transmission of pathogens and reducing workers’ health risk during landfill excavation.
Automatic Detection of Mandibular Fractures in Panoramic Radiographs Using Deep Learning
Authors: Son Dong-Min , Yoon Yeong-Ah , Kwon Hyuk-Ju , An Chang-Hyeon , Lee Sung-Hak
Published: May 2021

Mandibular fracture is one of the most frequent injuries in oral and maxillo-facial surgery. Radiologists diagnose mandibular fractures using panoramic radiography and cone-beam computed tomography (CBCT). Panoramic radiography is a conventional imaging modality, which is less complicated than CBCT. This paper proposes the diagnosis method of mandibular fractures in a panoramic radiograph based on a deep learning system without the intervention of radiologists. The deep learning system used has a one-stage detection called you only look once (YOLO). To improve detection accuracy, panoramic radiographs as input images are augmented using gamma modulation, multi-bounding boxes, single-scale luminance adaptation transform, and multi-scale luminance adaptation transform methods. Our results showed better detection performance than the conventional method using YOLO-based deep learning. Hence, it will be helpful for radiologists to double-check the diagnosis of mandibular fractures.
Classification of Non-Infectious and/or Immune Mediated Choroiditis: A Brief Overview of the Essentials
Authors: Herbort Carl P. , Mantovani Alessandro , Tugal-Tutkun Ilknur , Papasavvas Ioannis
Published: May 2021

The choroid was poorly accessible to imaging investigation until the last decade of the last century. With the availability of more precise imaging methods such as indocyanine green angiography (ICGA) and, later, optical coherence tomography (OCT), enhanced depth OCT (EDI-OCT), and OCT angiography (OCTA), appraisal of choroidal inflammation has substantially gained in accuracy. This allowed to precisely determine which structures were touched in the different non-infectious choroiditis entities and made it possible to classify this group of diseases, ICGA signs, mainly hypofluorescent lesions, were identified and described. Previous publications have divided angiographic findings into two main sets of signs: (1) irregular “geographic” hypofluorescent areas corresponding to choriocapillaris non-perfusion and (2) round more regular, hypofluorescent dark dots more evenly distributed in the fundus corresponding to more deep choroidal stromal foci. These distinct findings allowed to subdivide and classify choroiditis into choriocapillaritis and stromal choroiditis. Additional signs were identified from EDI-OCT and OCTA examination supporting the classification of choroiditis into choriocapillaritis and stromal choroiditis. Results: Diseases involving principally the choriocapillaris included Multiple Evanescent White Dot Syndrome (MEWDS), Acute Posterior Multifocal Placoid Pigment Epitheliopathy (APMPPE), Idiopathic Multifocal Choroiditis (MFC), and Serpiginous Choroiditis (SC) as well as mixed forms. Diseases primarily involving the choroidal stroma included HLA-A29 Birdshot Retinochoroiditis (BRC), Vogt-Koyanagi-Harada disease (VKH), Sympathetic Ophthalmia (SO), and Sarcoidosis chorioretinitis (SARC). Thanks to new imaging investigations of the choroid, it is now possible to classify and understand the diverse clinicopathological mechanisms in the group of non-infectious choroiditis entities.
Optimum Placement of Distribution Generation Units in Power System with Fault Current Limiters Using Improved Coyote Optimization Algorithm
Authors: Alghamdi Hisham
Published: May 2021

Electric power frameworks become intensely loaded because of the expanded power demand, and as a result, the power system faces great power losses and fault currents. The integration of Distribution Generation (DG) units plays a key role in minimizing the load pressure on a power system. DGs are transmitted with a high fault current, which surpasses the evaluations of circuit breakers. This paper presents various DG units’ optimal placement with Fault Current Limiters (FCLs) in different phases. The Improved Coyote Optimize Algorithm (ICOA) and Electrical Transient Analyzer Program (ETAP) are assessed for the proposed technique in terms of normal and faulty working status. Similarly, to enhance the efficiency of a distribution system, a fuzzy-based multi-objective mechanism is applied. The proposed method is employed on an IEEE 21-bus and 28-bus distribution system. The simulation analysis proved that the power losses and fault levels are reduced at an acceptable level.
Regional Population Forecast and Analysis Based on Machine Learning Strategy
Authors: Wang Chian-Yue , Lee Shin-Jye
Published: May 2021

Regional population forecast and analysis is of essence to urban and regional planning, and a well-designed plan can effectively construct a sound national infrastructure and stabilize positive population growth. Traditionally, either urban or regional planning relies on the opinions of demographers in terms of how the population of a city or a region will grow. Multi-regional population forecast is currently possible, carried out mainly on the basis of the Interregional Cohort-Component model. While this model has its unique advantages, several demographic rates are determined based on the decisions made by primary planners. Hence, the only drawback for cohort-component type population forecasting is allowing the analyst to specify the demographic rates of the future, and it goes without saying that this tends to introduce a biased result in forecasting accuracy. To effectively avoid this problem, this work proposes a machine learning-based method to forecast multi-regional population growth objectively. Thus, this work, drawing upon the newly developed machine learning technology, attempts to analyze and forecast the population growth of major cities in Taiwan. By effectively using the advantage of the XGBoost algorithm, the evaluation of feature importance and the forecast of multi-regional population growth between the present and the near future can be observed objectively, and it can further provide an objective reference to the urban planning of regional population.
The Systematic Bias of Entropy Calculation in the Multi-Scale Entropy Algorithm
Authors: Lu Jue , Wang Ze
Published: May 2021

Entropy indicates irregularity or randomness of a dynamic system. Over the decades, entropy calculated at different scales of the system through subsampling or coarse graining has been used as a surrogate measure of system complexity. One popular multi-scale entropy analysis is the multi-scale sample entropy (MSE), which calculates entropy through the sample entropy (SampEn) formula at each time scale. SampEn is defined by the “logarithmic likelihood” that a small section (within a window of a length m) of the data “matches” with other sections will still “match” the others if the section window length increases by one. “Match” is defined by a threshold of r times standard deviation of the entire time series. A problem of current MSE algorithm is that SampEn calculations at different scales are based on the same matching threshold defined by the original time series but data standard deviation actually changes with the subsampling scales. Using a fixed threshold will automatically introduce systematic bias to the calculation results. The purpose of this paper is to mathematically present this systematic bias and to provide methods for correcting it. Our work will help the large MSE user community avoiding introducing the bias to their multi-scale SampEn calculation results.
Positive Massage: An Intervention for Couples’ Wellbeing in a Touch-Deprived Era
Authors: Naruse Sayuri M. , Moss Mark
Published: May 2021

COVID-19 has brought not only fear and anxiety, but also legitimate restrictions of communication and consequential touch-deprivation in our daily lives. Couples’ relational wellbeing continues to be impacted by these COVID-19 related stressors. Protecting both personal and relational wellbeing is therefore particularly important at this time. Using a preventative intervention approach, the current paper argues the theoretical benefit of the Positive Massage programme and reports a qualitative analysis of stressed but healthy couples’ experience of engaging in the programme. Thirty-four participants completed 3 weekly classes and home-based practice of massage exchange. Data from an open text online questionnaire completed every week of the programme and again 3 weeks afterwards were analysed using thematic analysis. The identified themes included “holistic stress relief”, “relationship-promotion”, and “selves-care skill”. Couples perceived Positive Massage as an effective mutual support skill to relax and help one another by de-stressing, both emotionally and physically through verbal and nonverbal communication, creating gratitude, deeper connection and self-efficacy via quality time together and pleasurable touch. Theoretically and experientially, Positive Massage can be an effective preventative selves-care skill. Promoting the concept of selves-care and its practical application through Positive Massage would be beneficial for couples’ personal and relational wellbeing in a touch-deprived era.
Implementation of a System That Helps Novice Users Work with Linked Data
Authors: Oh Solgil , Yoo Sujin , Kim Yuri , Song Jisoo , Park Seongbin
Published: May 2021

On the Semantic Web, resources are connected to each other by the IRI. As the basic unit is comprised of linked data, machines can use semantic data and reason their relations without additional intervention on the Semantic Web. However, it is necessary for users who first encounter the Semantic Web to understand its underlying structure and some grammatical rules. This study suggests linking data sets of the Semantic Web through the Euler diagram, which does not require any prior knowledge. We performed a user study with our relationship-building system and verified that users could better understand linked data through the usage of the system. Users can indirectly be guided by using our Euler diagram-based data relationship-building system to understand the Semantic Web and its data linkage system. We also expect that the data sets defined through our system can be used in various applications.
Analysis of Internal Signal Perturbations in DC/DC and DC/AC Converters under Arc Fault
Authors: Luna Benjamin Vidales , Monroy-Morales José Luis , Madrigal Martínez Manuel , Torres-Lucio Domingo , Weber Serge , Schweitzer Patrick
Published: May 2021

The constant increase in electrical energy consumption has led to a growth of photovoltaic installations (PV) along with the corresponding power converters for proper operation. Power electronics converters represent a challenge to maintain the system’s performance and safety; one such problem is series DC Arc Fault (AF). DC AFs lead to fire risk, damaging the main bus and the loads when not detected and interrupted in time. Therefore, research about DC AFs in power electronics converters must be carried out to predict the behavior and help avoid damage to the system. In this work, an innovative hybrid multilevel inverter for PV applications is used to explore the effect of series DC AFs in the converters’ internal signals, with the aims of setting the bases for the development of a detection system for power electronics. Both stages of conversion (DC/DC and DC/AC) are presented. In addition, the placement of the MPPT converter was considered for the tests. The AF experimental tests were performed with a generator based on the UL1699B specifications. The measurements of signals were performed in strategic points of the DC side, and changes and how to exploit them are discussed. This study contributes to a better understanding of the DC AF phenomenon and provides new insights for the development of new PV system protections.
Zero-Width Quasi-Sliding Mode Band in the Presence of Non-Matched Uncertainties
Authors: Latosiński Paweł , Bartoszewicz Andrzej
Published: May 2021

Sliding mode control strategies are well known for ensuring robustness of the system with respect to disturbance and model uncertainties. For continuous-time plants, they achieve this property by confining the system state to a particular hyperplane in the state space. Contrary to this, discrete-time sliding mode control (DSMC) strategies only drive the system representative point to a certain vicinity of that hyperplane. In established literature on DSMC, the width of this vicinity has always been strictly greater than zero in the presence of uncertainties. Thus, ideal sliding motion was considered impossible for discrete-time systems. In this paper, a new approach to DSMC design is presented with the aim of driving the system representative point exactly onto the sliding hyperplane even in the presence of uncertainties. As a result, the quasi-sliding mode band width is effectively reduced to zero and ideal discrete-time sliding motion is ensured. This is achieved with the proper selection of the sliding hyperplane, using the unique properties of relative degree two sliding variables. It is further demonstrated that, even in cases where selection of a relative degree two sliding variable is impossible, one can use the proposed technique to significantly reduce the quasi-sliding mode band width.
Microgravity Survey to Detect Voids and Loosening Zones in the Vicinity of the Mine Shaft
Authors: Porzucek Slawomir , Loj Monika
Published: May 2021

In mining and post-mining areas, the assessment of the risks to the surface and its infrastructure from the opening or closed mine is of the utmost importance; particular attention should be paid to mine shafts. The risks include the occurrence of undetected voids or loosening zones in the rock mass. Their detection makes it possible to prevent their impact on a mine shaft and surface infrastructure. Geophysical methods, and in particular, a microgravity method lend themselves for the detection of changes in the distribution of masses (i.e., the density) due to voids and loosening zones. The paper presents the results of surface microgravity surveys in the vicinity of three mine shafts: under construction, working, and a liquidated one. Based on the gravity anomalies, the density distribution of the rock mass for all three cases was recognized. The properties of the anomalies allowed to determine which of the identified decreased density zones may pose a threat to the surface infrastructure or a mine shaft. The microgravity survey made inside the working mining shaft provided information on the density of rocks outside the shaft lining, regardless of the type of lining. No significant decrease of density was found, which means that there are no larger voids outside the shaft lining. Nevertheless, at a depth of 42 m in running sands layer, the decreasing density zone was located, which should be controlled. Additionally, measurements in two vertical profiles gave the possibility of directional tracking of density changes outside shaft lining. Such changes were observed on three boundaries of geological layers, with two of them being on the boundary of gypsum and other rocks.
Chemical Composition Variations of Altered and Unaffected Coals from the Huaibei Coalfield, China: Implications for Maturity
Authors: Feng Songbao , Wei Qiang , Li Xianqing
Published: May 2021

The composition characteristics of altered coals in the Huaibei Coalfield, China, was investigated through a comparative analysis between altered and unaffected coals from the Wolonghu, Taoyuan and Renlou coal mines. Results indicated that the altered coals in Wolonghu coal mine are mostly anthracite coals, with a maximum vitrinite reflectance of 1.6–3.9% (average of 2.9%). Coals from Wolonghu coal mine were mainly consisted of vitrinite (66.2–97.0%), followed by inertinite (2.0–4.0%) and exinite (0.4–6.9%). Differences in volatile matter content were observed between the altered coals in Wolonghu coal mine and unaffected coals from neighboring coal mines, implying that the chemical composition and maturity of coals were changed after magmatic alteration. In addition, differences in hydrogen element were noted among the coals from Wolonghu, Renlou and Taoyuan coal mines, and the phenomenon of “deficient in hydrogen element” was observed in Wolonghu coals. The aliphatic hydrocarbon structure parameters suggested that the aliphatic chain lengths of Wolonghu coals are shorter than those of coal samples from the Renlou and Taoyuan coal mines. In addition, maturity is positively correlated with hydrogen enrichment degree, but negatively related with aliphatic hydrocarbon structure. Coals from Renlou and Taoyuan coal mines showed great weight loss with various heating rates at temperatures of 0–1000 °C, whereas those from Wolonghu coal mine had less weight loss.
Thermally Accelerated Aging of Insulation Paper for Transformers with Different Insulating Liquids
Authors: Münster Tobias , Werle Peter , Hämel Kai , Preusel Jörg
Published: May 2021

The article presents issues related to the aging behavior of oil-paper insulations in transformers using different oil- and ester-based insulating fluids. Despite numerous conducted studies on the subject of oil-paper aging, the use of new insulating fluids is creating open questions. In addition, new liquids such as synthetic and natural esters, as well as oil of the newest generation, are being used. Furthermore, there is still little research on the formation of aging markers with this form of the dielectric. For this reason, in this contribution, oil-paper insulations with mineral oil-based insulating fluids, natural and synthetic esters, as well as oil from natural gas, are aged thermally accelerated at 130 °C over a duration of 15 weeks, by considering two cases of free-breathing and hermetically sealed transformers. Therefore, various aging markers are investigated to allow a condition assessment. The results show that differences exist between the fluids and design of the transformer, as in the aging rate of the paper and the formation of aging markers in the insulating liquid such as acids. These findings can be used to improve asset management strategies by a more precise determination of the aging state depending on the transformer type as well as the type of insulating fluid.
A Deep Learning Approach for Peak Load Forecasting: A Case Study on Panama
Authors: Ibrahim Bibi , Rabelo Luis
Published: May 2021

Predicting the future peak demand growth becomes increasingly important as more consumer loads and electric vehicles (EVs) start connecting to the grid. Accurate forecasts will enable energy suppliers to meet demand more reliably. However, this is a challenging problem since the peak demand is very nonlinear. This study addresses the research question of how deep learning methods, such as convolutional neural networks (CNNs) and long-short term memory (LSTM) can provide better support to these areas. The goal is to build a suitable forecasting model that can accurately predict the peak demand. Several data from 2004 to 2019 was collected from Panama’s power system to validate this study. Input features such as residential consumption and monthly economic index were considered for predicting peak demand. First, we introduced three different CNN architectures which were multivariate CNN, multivariate CNN-LSTM and multihead CNN. These were then benchmarked against LSTM. We found that the CNNs outperformed LSTM, with the multivariate CNN being the best performing model. To validate our initial findings, we then evaluated the robustness of the models against Gaussian noise. We demonstrated that CNNs were far more superior than LSTM and can support spatial-temporal time series data.
Technology Development and Spatial Diffusion of Auxiliary Power Sources in Trolleybuses in European Countries
Authors: Połom Marcin
Published: May 2021

Trolleybus transport is one of the classic means of public transport in cities. Its popularity varied in the past and was largely related to the fuel market situation. As fuel prices fell, electricity-powered transport lost popularity. The situation was similar during fuel crises. Trolleybuses gained in popularity then. Nowadays, the development of alternative power sources (APS) technology makes trolleybus transport partially independent of the overhead contact system, which is its great advantage. It is thus possible to develop trolleybus connections in areas where there is no justification for building overhead wiring infrastructure. The article analyses the development of on-board APS and their spatial diffusion in trolleybus systems in Europe. The main result of the research procedure indicates that the development of battery technologies, which could accelerate the closure of trolleybus transport due to the strong competition of electric buses not requiring an overhead contact line, allows for the dynamic development of this branch of transport. The situation in 71 trolleybus systems in Central and Western Europe which had any experience in the use of APS in 2011–2021 was examined. As a result of the analysis, the dynamics of APS diffusion were determined, in particular, a significant increase in the number of trolleybus systems using on-board batteries from 7 in 2011 to 44 in 2021.
Experimental Diagnosis of the Heat Pipe Solar Collector Malfunction. A Case Study
Authors: Znaczko Pawel , Szczepanski Emilian , Kaminski Kazimierz , Chamier-Gliszczynski Norbert , Kukulski Jacek
Published: May 2021

Work was carried out to diagnose irregularities in the operation of a vacuum-tube solar collector. Experimental investigations of the collector were carried out at the solar collector field test stand in the Laboratory of Solar Collectors at the Koszalin University of Technology. The scope of the work included the following: research on thermal efficiency characteristics, research on the temperature distribution on the solar collector manifold, and research on the geometric structure of the heat pipe and filling with the working medium. Based on the diagnostic tests carried out, the occurrence of incorrect sedimentation in the condenser on the neck of the heat pipe (44%) and an incorrect amount of working medium (66%) were found. The results show that the functioning of the heat pipe significantly depends on its geometric structure and the amount of working medium. Any irregularity at the production stage contributes to a reduction in the thermal efficiency of the solar collector. The results of the experimental research presented in this paper can be used in the diagnostic analyses of solar systems as well as in the organisation of the manufacturing processes of these systems.
Material Properties and Environmental Benefits of Hot-Mix Asphalt Mixes Including Local Crumb Rubber Obtained from Scrap Tires
Authors: Khiong Lim Min , Safiuddin Md. , Mannan Mohammad Abdul , Resdiansyah
Published: May 2021

This paper presents the results of a laboratory-based experimental investigation on the properties of asphalt binder and hot-mix asphalt (HMA) mixes modified by locally available crumb rubber, which was used as a partial replacement of asphalt by weight. In this study, fine crumb rubber with a particle size in the range of 0.3–0.6 mm, obtained from scrap tires, was added to the asphalt binder through the wet process. Crumb rubber contents of 5%, 10%, 15%, and 19% by weight of asphalt were added to the virgin binder in order to prepare the modified asphalt binder samples, while the unmodified asphalt binder was used as the control sample. The crumb rubber modified binder samples were examined for measuring viscosity indirectly using the penetration test, and temperature resistance using the softening point test. Later, both the modified and unmodified asphalt binders were used to produce HMA mixes. Two categories of HMA mix commonly used in Malaysia—namely, AC 14 (dense-graded) and SMA 14 (gap-graded)—were produced using the modified asphalt binders containing 5%, 10%, 15%, and 19% crumb rubber. Two AC 14 and SMA 14 control mixes were also produced, incorporating the unmodified asphalt binder (0% crumb rubber). All of the AC 14 and SMA 14 asphalt mixes were examined in order to determine their volumetric properties, such as bulk density, voids in total mix (VTM), voids in mineral aggregate (VMA), and voids filled with asphalt (VFA). In addition, the Marshall stability, Marshall flow, and stiffness of all of the AC 14 and SMA 14 mixes were determined. Test results indicated that the modified asphalt binders possessed higher viscosity and temperature resistance than the unmodified asphalt binder. The viscosity and temperature resistance of the asphalt binders increased with the increase in their crumb rubber content. The increased crumb rubber content also led to improvements in the volumetric properties (bulk density, VTM, VMA, and VFA) of the AC 14 and SMA 14 mixes. In addition, the performance characteristics of the AC 14 and SMA 14 mixes—such as Marshall stability, Marshall flow, and stiffness—increased with the increase in crumb rubber content. However, the AC 14 mixes performed much better than the SMA 14 mixes. The overall research findings suggest that crumb rubber can be used to produce durable and sustainable HMA mixes, with manifold environmental benefits, for use in flexible pavements carrying the heavy traffic load of highways.
Global Trends in Research on Wild-Simulated Ginseng: Quo Vadis?
Authors: Shin Seongmin , Park Mi Sun , Lee Hansol , Lee Seongeun , Lee Haeun , Kim Tae Hoon , Kim Hyo Jin
Published: May 2021

To the best of our knowledge, no study has systematically reviewed and analyzed the research trends of wild-simulated ginseng (WSG) used for food or medicinal purposes in many countries. WSG, a non-timber forest product, has been traditionally produced using agroforestry practices, and it has been consumed in various ways for a long time. WSG has a great demand in the market due to its medicinal effects, particularly in improving forest livelihoods and human health. Due to the significance of WSG, we conducted this research to explore the global research trends on WSG using systematic review methodology and keyword analysis. We used two international academic databases, the Web of Science and SCOPUS, to extract 115 peer-reviewed articles published from 1982 to 2020. The research subjects, target countries, and keywords were analyzed. Our results indicate four categories of WSG research subjects, namely growth conditions, components, effects on humans/animals, and the environment of WSG, and the case studies were mainly from the Republic of Korea, China, and the USA. Through topic modelling, research keywords were classified into five groups, namely medicinal effects, metabolite analysis, genetic diversity, cultivation conditions, and bioactive compounds. We observed that the research focus on WSG changed from the biological properties and cultivation conditions of WSG to the precise identification and characterization of bioactive metabolites of WSG. This change indicates an increased academic interest in the value-added utilization of WSG.
Turbulence Intensity Modulation by Micropolar Fluids
Authors: Sofiadis George , Sarris Ioannis
Published: May 2021

Fluid microstructure nature has a direct effect on turbulence enhancement or attenuation. Certain classes of fluids, such as polymers, tend to reduce turbulence intensity, while others, like dense suspensions, present the opposite results. In this article, we take into consideration the micropolar class of fluids and investigate turbulence intensity modulation for three different Reynolds numbers, as well as different volume fractions of the micropolar density, in a turbulent channel flow. Our findings support that, for low micropolar volume fractions, turbulence presents a monotonic enhancement as the Reynolds number increases. However, on the other hand, for sufficiently high volume fractions, turbulence intensity drops, along with Reynolds number increment. This result is considered to be due to the effect of the micropolar force term on the flow, suppressing near-wall turbulence and enforcing turbulence activity to move further away from the wall. This is the first time that such an observation is made for the class of micropolar fluid flows, and can further assist our understanding of physical phenomena in the more general non-Newtonian flow regime.
Numerical Computation of Dufour and Soret Effects on Radiated Material on a Porous Stretching Surface with Temperature-Dependent Thermal Conductivity
Authors: Naseem Tahir , Nazir Umar , El-Zahar Essam R. , Algelany Ahmed M. , Sohail Muhammad
Published: May 2021

The current research is prepared to address the transport phenomenon in a hydro-magnetized flow model on a porous stretching sheet. Mass and heat transport are modeled via temperature dependent models of thermal conductivity and diffusion coefficients. Accordingly, the involvement of radiation, chemical reaction, the Dufour effect, and the Soret effect are involved. The flow presenting expression has been modeled via boundary layer approximation and the flow is produced due to the experimental stretching sheet. The governing equations have been approximated numerically via shooting method. The efficiency of the scheme is established by including the comparative study. Moreover, a decline in the velocity field is recorded against the escalating values of the porosity parameter and the magnetic parameter.
Decoupling of Mechanical and Transport Properties in Organogels via Solvent Variation
Authors: Mineart Kenneth P. , Hong Cameron , Rankin Lucas A.
Published: May 2021

Organogels have recently been considered as materials for transdermal drug delivery media, wherein their transport and mechanical properties are among the most important considerations. Transport through organogels has only recently been investigated and findings highlight an inextricable link between gels’ transport and mechanical properties based upon the formulated polymer concentration. Here, organogels composed of styrenic triblock copolymer and different aliphatic mineral oils, each with a unique dynamic viscosity, are characterized in terms of their quasi-static uniaxial mechanical behavior and the internal diffusion of two unique solute penetrants. Mechanical testing results indicate that variation of mineral oil viscosity does not affect gel mechanical behavior. This likely stems from negligible changes in the interactions between mineral oils and the block copolymer, which leads to consistent crosslinked network structure and chain entanglement (at a fixed polymer concentration). Conversely, results from diffusion experiments highlight that two penetrants—oleic acid (OA) and aggregated aerosol-OT (AOT)—diffuse through gels at a rate inversely proportional to mineral oil viscosity. The inverse dependence is theoretically supported by the hydrodynamic model of solute diffusion through gels. Collectively, our results show that organogel solvent variation can be used as a design parameter to tailor solute transport through gels while maintaining fixed mechanical properties.
Interventions for Nursing Home Residents with Dysphagia—A Scoping Review
Authors: Melgaard Dorte , Westergren Albert , Skrubbeltrang Conni , Smithard David
Published: May 2021

Oropharyngeal dysphagia is common in nursing home residents. The objective of this scoping review was to summarize and disseminate the findings from the literature on interventions for dysphagia in nursing home residents. Searches were conducted in four databases. The criteria for including the studies were nursing home residents, dysphagia, interventions, original research, published in English, Danish, Norwegian, or Swedish with no restriction placed regarding publication date. Excluded were literature reviews, editorial comments, conference abstracts, protocols, papers not available in full text, and studies with a mixed population, for example, geriatric patients and nursing home residents and where the results were not separated between the groups. A total of 14 papers were included and analyzed. The included papers represented interventions focusing on feeding intervention, oral hygiene, caregiver algorithm, stimulation (taste and smell), teaching the residents what to eat, mobilization of the spine, exercises/training, and positioning. This scoping review identifies sparse knowledge about interventions affecting nursing home residents’ dysphagia. But the results indicate that multi-component interventions, including staff training, training of residents, and/or next of kin, might be successful. This scoping review clarifies that there is a need for well-designed studies that uncover which specific interventions have an effect in relation to nursing home residents with dysphagia and can serve as a guide for designing multi-component person-centered intervention studies. Future studies should implement high evidence study designs, define the measures of dysphagia, and quantify the severity of dysphagia, its underlying diseases, and comorbidities.