bluuebunny/crossref_metadata_2025 huggingface dataset:
The Evolution and Influencing Factors of Total Factor Productivity of Grain Production Environment: Evidence from Poyang Lake Basin, China
Authors: Bao Bingfei , Jiang Anli , Jin Shengtian , Zhang Rui
Published: June 2021

The total factor productivity (hereafter TFP) of grain production is important to achieve balanced development, while environmental factors are an important part of TEP. In order to explore the characteristics and patterns of the temporal and spatial evolution of the environmental total factor productivity (hereafter ETFP), the Malmquist-Luerberger index, and the spatial autoregressive panel (SAR panel) model were adopted to analyze the evolutionary rules and the influencing factors of ETFP. In this study, we took Poyang Lake, one of China’s main grain production areas, as a study area, and carried out empirical research based on grain production statistical data. The results show that: (1) ETFP shows a growth trend with the increase of grain production from 2001 to 2017, and a great potential for improvement exists. Moreover, from the perspective of time sequence evolution and decomposition of ETFP, which belongs to the dual-track driver of environmental technical efficiency and environmental technological progress, relevant technologies play an important role in promoting the improvement of TEFP; (2) Given that the objective conditions of gain production remain unchanged, the fact that the urbanization rate and average annual rainfall have a negative effect on ETFP, the explanatory variables such as the business scale per worker, the proportion of grain growing population, industrial agglomeration, the proportion of grain sown area and the average annual temperature all play a positive role. Among the variables, the business scale per worker and the proportion of grain growing population significantly affect ETFP at the 1% level. The average annual rainfall, industrial agglomeration and the proportion of grain sown area significantly affect the ETFP at the 5% level. The average annual temperature significantly affects the ETFP at the 10% level.
Covalent Immobilization of Organic Photosensitizers on the Glass Surface: Toward the Formation of the Light-Activated Antimicrobial Nanocoating
Authors: Nyga Aleksandra , Czerwińska-Główka Dominika , Krzywiecki Maciej , Przystaś Wioletta , Zabłocka-Godlewska Ewa , Student Sebastian , Kwoka Monika , Data Przemysław , Blacha-Grzechnik Agata
Published: June 2021

Two highly efficient commercial organic photosensitizers—azure A (AA) and 5-(4-aminophenyl)-10,15,20-(triphenyl)porphyrin (APTPP)—were covalently attached to the glass surface to form a photoactive monolayer. The proposed straightforward strategy consists of three steps, i.e., the initial chemical grafting of 3-aminopropyltriethoxysilane (APTES) followed by two chemical postmodification steps. The chemical structure of the resulting mixed monolayer (MIX_TC_APTES@glass) was widely characterized by X-ray photoelectron (XPS) and Raman spectroscopies, while its photoactive properties were investigated in situ by UV–Vis spectroscopy with α-terpinene as a chemical trap. It was shown that both photosensitizers retain their activity toward light-activated generation of reactive oxygen species (ROS) after immobilization on the glassy surface and that the resulting nanolayer shows high stability. Thanks to the complementarity of the spectral properties of AA and APTPP, the effectiveness of the ROS photogeneration under broadband illumination can be optimized. The reported light-activated nanocoating demonstrated promising antimicrobial activity toward Escherichia coli (E. coli), by reducing the number of adhered bacteria compared to the unmodified glass surface.
In-Situ Alloy Formation of a WMoTaNbV Refractory Metal High Entropy Alloy by Laser Powder Bed Fusion (PBF-LB/M)
Authors: Huber Florian , Bartels Dominic , Schmidt Michael
Published: June 2021

High entropy or multi principal element alloys are a promising and relatively young concept for designing alloys. The idea of creating alloys without a single main alloying element opens up a wide space for possible new alloy compositions. High entropy alloys based on refractory metals such as W, Mo, Ta or Nb are of interest for future high temperature applications e.g., in the aerospace or chemical industry. However, producing refractory metal high entropy alloys by conventional metallurgical methods remains challenging. For this reason, the feasibility of laser-based additive manufacturing of the refractory metal high entropy alloy W20Mo20Ta20Nb20V20 by laser powder bed fusion (PBF-LB/M) is investigated in the present work. In-situ alloy formation from mixtures of easily available elemental powders is employed to avoid an expensive atomization of pre-alloyed powder. It is shown that PBF-LB/M of W20Mo20Ta20Nb20V20 is in general possible and that a complete fusion of the powder mixture without a significant number of undissolved particles is achievable by in-situ alloy formation during PBF-LB/M when selecting favorable process parameter combinations. The relative density of the samples with a dimension of 6 × 6 × 6 mm3 reaches, in dependence of the PBF-LB/M parameter set, 99.8%. Electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM) measurements confirm the presence of a single bcc-phase. Scanning electron microscopy (SEM) images show a dendritic and/or cellular microstructure that can, to some extent, be controlled by the PBF-LB/M parameters.
Fréedericksz Transitions in 6CB Based Ferronematics—Effect of Magnetic Nanoparticles Size and Concentration
Authors: Zakutanská Katarína , Petrov Danil , Kopčanský Peter , Węgłowska Dorota , Tomašovičová Natália
Published: June 2021

In this paper, results acquired from capacitance measurements performed on composites based on nematic liquid crystal 4-cyano-4′-hexylbiphenyl (6CB) and spherical iron oxide nanoparticles of various sizes are presented. Electric and magnetic Fréedericksz transitions, as well as structural transitions in combined electric and magnetic fields, were investigated. The obtained results showed the lowering of the threshold magnetic field with an increase in the volume concentration of nanoparticles. Estimations based on results obtained from measurements suggest soft anchoring between liquid crystal director and nanoparticles magnetization vector.
Investigation into the Hybrid Production of a Superelastic Shape Memory Alloy with Additively Manufactured Structures for Medical Implants
Authors: Hamann Isabell , Gebhardt Felix , Eisenhut Manuel , Koch Peter , Thielsch Juliane , Rotsch Christin , Drossel Welf-Guntram , Heyde Christoph-Eckhard , Leimert Mario
Published: June 2021

The demographic change in and the higher incidence of degenerative bone disease have resulted in an increase in the number of patients with osteoporotic bone tissue causing. amongst other issues, implant loosening. Revision surgery to treat and correct the loosenings should be avoided, because of the additional patient stress and high treatment costs. Shape memory alloys (SMA) can help to increase the anchorage stability of implants due to their superelastic behavior. The present study investigates the potential of hybridizing NiTi SMA sheets with additively manufactured Ti6Al4V anchoring structures using laser powder bed fusion (LPBF) technology to functionalize a pedicle screw. Different scanning strategies are evaluated, aiming for minimized warpage of the NiTi SMA sheet. For biomechanical tests, functional samples were manufactured. A good connection between the additively manufactured Ti6Al4V anchoring structures and NiTi SMA substrate could be observed though crack formation occurring at the transition area between the two materials. These cracks do not propagate during biomechanical testing, nor do they lead to flaking structures. In summary, the hybrid manufacturing of a NiTi SMA substrate with additively manufactured Ti6Al4V structures is suitable for medical implants.
The One-Year In Vivo Comparison of Lithium Disilicate and Zirconium Dioxide Inlays
Authors: Behera Rini , Mishra Lora , Divakar Darshan Devang , Al-Kheraif Abdulaziz A. , Singh Naomi Ranjan , Lukomska-Szymanska Monika
Published: June 2021

The objective of the present study was to evaluate the one-year clinical performance of lithium disilicate (LD) and zirconium dioxide (ZrO2) class II inlay restorations. Thirty healthy individuals who met the inclusion criteria were enrolled for the study. The patients were randomly divided into two study groups (n = 15): LD (IPS e.max press) and ZrO2 (Dentcare Zirconia). In the ZrO2 group, the internal surfaces of the inlays were sandblasted and silanized with Monobond N (Ivoclar, Leichsteistein, Germany). In the LD group, the internal surfaces of the inlays were etched with 5% hydrofluoric acid. The ceramic inlays were cemented with self-cure resin cement (Multilink N). Clinical examinations were performed using modified United State Public Health Codes and Criteria (USPHS) after 2 weeks, 4 weeks, 6 months and 1 year. The one-year survival rate was evaluated. In total, one failure was observed in the ZrO2 group. The survival probability after 1 year for the ZrO2 inlays was 93%, and for the LD inlays was 100%, which was statistically insignificant. The differences between both groups for most USPHS criteria (except for colour match) were statistically insignificant. Within the imitations of the present study, the lithium disilicate- and zirconia dioxide-based inlays exhibited comparable clinical performances. However, the colour and translucency match was superior for the lithium disilicate restorations.
Visible Light-Driven Photocatalytic Activity and Kinetics of Fe-Doped TiO2 Prepared by a Three-Block Copolymer Templating Approach
Authors: Mancuso Antonietta , Sacco Olga , Vaiano Vincenzo , Bonelli Barbara , Esposito Serena , Freyria Francesca Stefania , Blangetti Nicola , Sannino Diana
Published: June 2021

Fe-doped titania photocatalysts (with 1, 2.5, and 3.5 wt. % Fe nominal content), showing photocatalytic activity under visible light, were prepared by a soft-template assisted sol–gel approach in the presence of the triblock copolymer Pluronic P123. An undoped TiO2 photocatalyst was also prepared for comparison. The photocatalysts were characterized by means of X-ray powder Diffraction (XRPD), Quantitative Phase Analysis as obtained by Rietveld refinement, Diffuse Reflectance (DR) UV−Vis spectroscopy, N2 adsorption/desorption at −196 °C, electrophoretic mobility in water (ζ-potential), and X-ray photoelectron spectroscopy (XPS). The physico-chemical characterization showed that all the samples were 100% anatase phase and that iron was present both in the bulk and at the surface of the Fe-doped TiO2. Indeed, the band gap energy (Eg) decreases with the Fe content, with Tauc’s plot determined values ranging from 3.35 (undoped TiO2) to 2.70 eV (3.5 wt. % Fe). Notwithstanding the obtained Eg values, the photocatalytic activity results under visible light highlighted that the optimal Fe content was equal to 2.5 wt. % (Tauc’s plot determined Eg = 2.74 eV). With the optimized photocatalyst and in selected operating conditions, under visible light it was possible to achieve 90% AO7 discoloration together with a TOC removal of 40% after 180 min. The kinetic behavior of the photocatalyst was also analyzed. Moreover, the tests in the presence of three different scavengers revealed that the main reactive species are (positive) holes and superoxide species. Finally, the optimized photocatalyst was also able to degrade phenol under visible light.
Mechanical and Physicochemical Properties of 3D-Printed Agave Fibers/Poly(lactic) Acid Biocomposites
Authors: Figueroa-Velarde Valeria , Diaz-Vidal Tania , Cisneros-López Erick Omar , Robledo-Ortiz Jorge Ramón , López-Naranjo Edgar J. , Ortega-Gudiño Pedro , Rosales-Rivera Luis Carlos
Published: June 2021

In order to provide a second economic life to agave fibers, an important waste material from the production of tequila, filaments based on polylactic acid (PLA) were filled with agave fibers (0, 3, 5, 10 wt%), and further utilized to produce biocomposites by fused deposition modeling (FDM)-based 3D printing at two raster angles (−45°/45° and 0°/90°). Differential scanning calorimetry, water uptake, density variation, morphology, and composting of the biocomposites were studied. The mechanical properties of the biocomposites (tensile, flexural, and Charpy impact properties) were determined following ASTM international norms. The addition of agave fibers to the filaments increased the crystallinity value from 23.7 to 44.1%. However, the fibers generated porous structures with a higher content of open cells and lower apparent densities than neat PLA pieces. The printing angle had a low significant effect on flexural and tensile properties, but directly affected the morphology of the printed biocomposites, positively influenced the impact strength, and slightly improved the absorption values for biocomposites printed at −45°/45°. Overall, increasing the concentrations of agave fibers had a detrimental effect on the mechanical properties of the biocomposites. The disintegration of the biocomposites under simulated composting conditions was slowed 1.6-fold with the addition of agave fibers, compared to neat PLA.
Al Matrix Composites Reinforced by Ti and C Dedicated to Work at Elevated Temperature
Authors: Hekner Bartosz , Myalski Jerzy , Wrześniowski Patryk , Maciąg Tomasz
Published: June 2021

In this paper, the applicability of aluminium matrix composites to high-temperature working conditions (not exceeding the Al melting point) was evaluated. The behaviour of Al-Ti-C composites at elevated temperatures was described based on microstructural and phase composition observations for composites heated at temperatures of 540 and 600 °C over differing time intervals from 2 to 72 h. The materials investigated were aluminium matrix composites (AMC) reinforced with a spatial carbon (C) structure covered by a titanium (Ti) layer. This layer protected the carbon surface against contact with the aluminium during processing, protection which was maintained for the material’s lifetime and ensured the required phase compositions of Al4C3 phase limitation and AlTi3 phase creation. It was also proved that heat treatment influenced not only phase compositions but also the microstructure of the material, and, as a consequence, the properties of the composite.
Air Permeability of Maraging Steel Cellular Parts Made by Selective Laser Melting
Authors: Dhinakar Annadurai , Li Bai-En , Chang Yo-Cheng , Chiu Kuo-Chi , Chen Jhewn-Kuang
Published: June 2021

Additive manufacturing, such as selective laser melting (SLM), can be used to manufacture cellular parts. In this study, cellular coupons of maraging steels are prepared through SLM by varying hatch distance. Air flow and permeability of porous maraging steel blocks are obtained for samples of different thickness based on the Darcy equation. By reducing hatch distance from 0.75 to 0.4 mm, the permeability decreases from 1.664 × 10−6 mm2 to 0.991 × 10−6 mm2 for 4 mm thick coupons. In addition, by increasing the thickness from 2 to 8 mm, the permeability increases from 0.741 × 10−6 mm2 to 1.345 × 10−6 mm2 at 16.2 J/mm3 energy density and 0.14 MPa inlet pressure. Simulation using ANSYS-Fluent is conducted to observe the pressure difference across the porous coupons and is compared with the experimental results. Surface artifacts and the actual morphology of scan lines can cause the simulated permeability to deviate from the experimental values. The measured permeability of maraging steel coupons is regression fit with both energy density and size of samples which provide a design guideline of porous mold inserts for industry applications such as injection molding.
Mechanical Properties Enhancement of the Au-Cu-Al Alloys via Phase Constitution Manipulation
Authors: Goo Kang-Wei , Chiu Wan-Ting , Toriyabe Ayano , Homma Masahiro , Umise Akira , Tahara Masaki , Goto Kenji , Sannomiya Takumi , Hosoda Hideki
Published: June 2021

To enhance the mechanical properties (e.g., strength and elongation) of the face-centered cubic (fcc) α-phase in the Au-Cu-Al system, this study focused on the introduction of the martensite phase (doubled B19 (DB19) crystal structure of Au2CuAl) via the manipulation of alloy compositions. Fundamental evaluations, such as microstructure observations, phase identifications, thermal analysis, tensile behavior examinations, and reflectance analysis, have been conducted. The presence of fcc annealing twins was observed in both the optical microscope (OM) and the scanning electron microscope (SEM) images. Both strength and elongation of the alloys were greatly promoted while the DB19 martensite phase was introduced into the alloys. Amongst all the prepared specimens, the 47Au41Cu12Al and the 44Au44Cu12Al alloys performed the optimized mechanical properties. The enhancement of strength and ductility in these two alloys was achieved while the stress plateau was observed during the tensile deformation. A plot of the ultimate tensile strength (UTS) against fracture strain was constructed to illustrate the effects of the introduction of the DB19 martensite phase on the mechanical properties of the alloys. Regardless of the manipulation of the alloy compositions and the introduction of the DB19 martensite phase, the reflectance stayed almost identical to pure Au.
Analysis of Microstructure and Mechanical Properties of AlSi11 after Chip Recycling, Co-Extrusion, and Arc Welding
Authors: Noga Piotr , Tuz Lechosław , Żaba Krzysztof , Zwoliński Adam
Published: June 2021

Recycling of raw materials and is crucial for the production of new products for the global economy. The aim here is, on the one hand, to reduce energy consumption, and, on the other hand, to obtain materials with similar functional properties. The study undertook research on the possibility of processing AlSi11 aluminum chips by compaction and co-extruding to obtain a product in the form of a flat bar with mechanical properties not lower than those of the cast materials. The performed tests and the developed technique allowed to obtain flat bars with more favorable mechanical properties (Yield Strength YS ≥ 155 MPa; Ultimate Tensile Strength UTS ≥ 212 MPa) than the castings (YS ≥ 70 MPa ≥ 150 MPa). The weldability evaluation tests revealed that the material is susceptible to porosity. The presence of pores, which reduces the cross-section (up to 60%), reduces the tensile strength (up to 20 MPa). The typical joint structure and plasticity is obtained, which indicate the possibility of tensile strength improvement.
Novel Triarylamine-Based Hole Transport Materials: Synthesis, Characterization and Computational Investigation
Authors: Nhari Laila M. , El-Shishtawy Reda M. , Lu Qiuchen , Li Yuanzuo , Asiri Abdullah M.
Published: June 2021

Three novel triarylamine-based electron-rich chromophores were synthesized and fully characterized. Compounds 1 and 2 were designed with electron-rich triphenylamine skeleton bearing two and four decyloxy groups namely, 3,4-bis(decyloxy)-N,N-diphenylaniline and N-(3,4-bis(decyloxy)phenyl)-3,4-bis(decyloxy)-N-phenylaniline, respectively. The well-known electron-rich phenothiazine was introduced to diphenylamine moiety through a thiazole ring to form N,N-bis(3,4-bis(decyloxy)phenyl)-5-(10H-phenothiazin-2-yl)thiazol-2-amine (Compound 3). These three novel compounds were fully characterized and their UV–vis absorption indicated their transparency as a favorable property for hole transport materials (HTMs) suitable for perovskite solar cells. Cyclic voltammetry measurements revealed that the HOMO energy levels were in the range 5.00–5.16 eV for all compounds, indicating their suitability with the HOMO energy level of the perovskite photosensitizer. Density functional theory (DFT) and time-dependent DFT (TD-DFT) have been used to investigate the possibility of the synthesized compounds to be utilized as HTMs for perovskite solar cells (PSCs). The computational investigation revealed that the hole mobility of Compound 1 was 1.08 × 10−2 cm2 V−1 s−1, and the substitution with two additional dialkoxy groups on the second phenyl ring as represented by Compound 2 significantly boosted the hole mobility to reach the value 4.21 × 10−2 cm2 V−1 s−1. On the other hand, Compound 3, in which the third phenyl group was replaced by a thiazole-based phenothiazine, the value of hole mobility decreased to reach 5.93 × 10−5 cm2 V−1 s−1. The overall results indicate that these three novel compounds could be promising HTMs for perovskite solar cells.
Tuning of the Structure and Magnetocaloric Effect of Mn1−xZrxCoGe Alloys (Where x = 0.03, 0.05, 0.07, and 0.1)
Authors: Kutynia Karolina , Gębara Piotr
Published: June 2021

The aim of the present work is to study the influence of a partial substitution of Mn by Zr in MnCoGe alloys. The X-ray diffraction (XRD) studies revealed a coexistence of the orthorhombic TiNiSi-type and hexagonal Ni2In- type phases. The Rietveld analysis showed that the changes in lattice constants and content of recognized phases depended on the Zr addition. The occurrence of structural transformation was detected. This transformation was confirmed by analysis of the temperature dependence of exponent n given in the relation ΔSM = C·(BMAX)n. A decrease of the Curie temperature with an increase of the Zr content in the alloy composition was detected. The magnetic entropy changes were 6.93, 13.42, 3.96, and 2.94 J/(kg K) for Mn0.97Zr0.03CoGe, Mn0.95Zr0.05CoGe, Mn0.93Zr0.07CoGe, and Mn0.9Zr0.1CoGe, respectively. A significant rise in the magnetic entropy change for samples doped by Zr (x = 0.05) was caused by structural transformation.
Numerical Investigation of Degradation of 316L Steel Caused by Cavitation
Authors: Maurin Artur
Published: June 2021

The degradation process of 316L stainless steel caused by cavitation was investigated by means of finite element analysis. The damage characteristics of metal specimens subjected to the cavitation bubble collapse process were recreated by simulation with a micro-jet water hammer. The simulation results were compared with the cavitation pits created in the experimental tests. In the experiment, different inlet and outlet pressures in a test chamber with a system of barricade exciters differentiated the erosion process results. Hydrodynamic cavitation caused uneven distribution of the erosion over the specimens’ surface, which has been validated by roughness measurements, enabling localisation and identification of the shape and topography of the impact pits. The erosion rate of the steel specimens was high at the beginning of the test and decreased over time, indicating the phase transformation and/or the strain-hardening of the surface layer. A numerical simulation showed that the impact of the water micro-jet with a velocity of 100 m/s exceeds the tensile strength of 316L steel, and produces an impact pit. The subsequent micro-jet impact on the same zone deepens the pit depth only to a certain extent due to elastoplastic surface hardening. The correlation between post-impact pit geometry and impact velocity was investigated.
A Novel Dry Treatment for Municipal Solid Waste Incineration Bottom Ash for the Reduction of Salts and Potential Toxic Elements
Authors: Abis Marco , Bruno Martina , Simon Franz-Georg , Grönholm Raul , Hoppe Michel , Kuchta Kerstin , Fiore Silvia
Published: June 2021

The main obstacle to bottom ash (BA) being used as a recycling aggregate is the content of salts and potential toxic elements (PTEs), concentrated in a layer that coats BA particles. This work presents a dry treatment for the removal of salts and PTEs from BA particles. Two pilot-scale abrasion units (with/without the removal of the fine particles) were fed with different BA samples. The performance of the abrasion tests was assessed through the analyses of particle size and moisture, and that of the column leaching tests at solid-to-liquid ratios between 0.3 and 4. The results were: the particle-size distribution of the treated materials was homogeneous (25 wt % had dimensions <6.3 mm) and their moisture halved, as well as the electrical conductivity of the leachates. A significant decrease was observed in the leachates of the treated BA for sulphates (44%), chlorides (26%), and PTEs (53% Cr, 60% Cu and 8% Mo). The statistical analysis revealed good correlations between chloride and sulphate concentrations in the leachates with Ba, Cu, Mo, and Sr, illustrating the consistent behavior of the major and minor components of the layer surrounding BA particles. In conclusion, the tested process could be considered as promising for the improvement of BA valorization.
Degradation Mechanisms of Metal-Supported Solid Oxide Cells and Countermeasures: A Review
Authors: Zhou Zhipeng , Nadimpalli Venkata Karthik , Pedersen David Bue , Esposito Vincenzo
Published: June 2021

Metal-supported oxide cells (MSCs) are considered as the third-generation solid oxide cells (SOCs) succeeding electrolyte-supported (first generation) and anode-supported (second generation) cells, which have gained much attention and progress in the past decade. The use of metal supports and advanced technical methods (such as infiltrated electrodes) has vastly improved cell performance, especially with its rapid startup ability and power density, showing a significant decrease in raw materials cost. However, new degradation mechanisms appeared, limiting the further improvement of the performance and lifetime. This review encapsulates the degradation mechanisms and countermeasures in the field of MSCs, reviewing the challenges and recommendations for future development.
Transient Hyperinsulinemic Hypoglycemia Linked to PAX6 Mutation
Authors: Kim Jee-Min , Kim Seul-Ki , Kim Shin-Hee , Cho Won-Kyoung , Cho Kyoung-Soon , Jung Min-Ho , Suh Byung-Kyu , Ahn Moon-Bae
Published: June 2021

Prolonged hyperinsulinemic hypoglycemia in infancy can result in developmental sequelae. A mutation in the paired box-6 gene (PAX6) has been reported to cause disorders in oculogenesis and neurogenesis. A limited number of cases of diabetes mellitus in adults with a PAX6 mutation suggest that the gene also plays a role in glucose homeostasis. The present case report describes a boy with a PAX6 mutation, born with anophthalmia, who underwent hypoglycemic seizures starting at 5 months old, and showed a prediabetic condition at 60 months. This patient provides novel evidence that connects PAX6 to glucose homeostasis and highlights that life-threatening hypoglycemia or early onset glucose intolerance may be encountered. The role of PAX6 in glucose metabolism and insulin regulation should be further investigated.
Comparison of COVID-19 Pandemic-Related Stress among Frontline Medical Personnel in Daegu City, Korea
Authors: Shin Su-Jeong , Kim Yun-Jeong , Ryoo Hyun-Wook , Moon Sungbae , Lee Sang-Hun , Moon You-Ho , Jang Tae-Chang , Park Dong-Chan
Published: June 2021

Background and Objectives: Frontline medical staff usually experience high levels of stress, which could greatly impact their work output. We conducted a survey to investigate the level of stress and its association with job types, work departments, and medical centers among COVID-19 pandemic frontline medical personnel. Materials and Methods: We conducted a cross-sectional survey using a self-administered questionnaire among 307 frontline medical staff who cared for COVID-19 patients in Daegu city. We used a 33-item questionnaire to assess respondents’ general characteristics, job stress, personal effects associated with the COVID-19 pandemic, and their stress level. A general health questionnaire-12 (GHQ-12) was included in our questionnaire. Results: Majority (74.3%) of the respondents were in the stress group. The mean GHQ-12 score was 14.31 ± 4.96. More females (67.4%, p < 0.05) and nurses (73.3%, p = 0.001) were in the stress group compared to males and doctors. Medical staff in the general ward considered the severity of the COVID-19 pandemic situation higher. Nurses perceived work changes (p < 0.05), work burden (p < 0.05), and personal impact (p < 0.05) more serious than doctors. Medical staff in Level 3 emergency department (ED) perceived a lack of real-time information (p = 0.012), a lack of resources, and negative personal impacts associated with the pandemic as more serious than staff in Level 1 and Level 2 EDs. Medical staff in the intensive care unit perceived work changes (p < 0.05), work burden (p < 0.05), and lack of personal protective equipment (p = 0.002) as more serious than staff in the ED and general ward. Conclusion: Providing real-time information and resources for reducing work burden and negative personal impact is central to maximizing the work output of the COVID-19 pandemic frontline medical staff. Supporting their mental health through regular programs and intervention is also imperative.
Fear of Falling, Recurrence of Falls, and Quality of Life in Patients with a Low Energy Fracture—Part II of an Observational Study
Authors: van der Vet Puck C. R. , Kusen Jip Q. , Rohner-Spengler Manuela , Link Björn-Christian , Houwert Roderick M. , Knobe Matthias , Babst Reto , Henzen Christoph , Schmid Lukas , Beeres Frank J. P.
Published: June 2021

Background and objective: Falls in elderly cause injury, mortality, and loss of independence, making Fear of Falling (FoF) a common health problem. FoF relates to activity restriction and increased fall risk. A voluntary intervention including fall risk assessment and prevention strategies was implemented to reduce falls in elderly patients with low energy fractures (LEF). The primary purpose of this study was to evaluate FoF and the number of subsequent falls in trauma patients one year after a LEF. The secondary aim was to examine how FoF affects patients’ lives in terms of Quality of Life (QoL), mobility, and activity levels. Finally, participation in the voluntary fall prevention program (FPP) was evaluated. Materials and Methods: Observational cohort study in one Swiss trauma center. LEF patients, treated between 2012 and 2015, were analyzed one year after injury. Primary outcomes were Falls-Efficacy Score-International (FES-I) and number of subsequent falls. Secondary outcomes were EuroQoL-5-Dimensions-3-Levels (EQ5D-3L), mobility, activity levels, and participation in the FPP. Subgroup analysis was performed for different age categories. Results: 411 patients were included for analysis. Mean age was 72 ± 9.3, mean FES-I was 21.1 ± 7.7. Forty percent experienced FoF. A significant negative correlation between FoF and QoL (R = 0.64; p < 0.001) was found. High FoF correlated with lower activity levels (R= −0.288; p < 0.001). Six percent visited the FPP. Conclusions: At follow-up, 40% suffered from FoF which seems to negatively affect patients’ QoL. Nevertheless, participation in the FPP was low. Simply informing patients about their susceptibility to falls and recommending participation in FPPs seems insufficient to motivate and recruit patients into FPPs. We suggest implementing repeated fall risk- and FoF screenings as standard procedures in the follow-up of LEF, especially in patients aged over 75 years.
Statins in Healthy Adults: A Meta-Analysis
Authors: Sandwith Lee , Forget Patrice
Published: June 2021

Background and Objectives: In this paper, we investigated the efficacy of statin therapy on cardiovascular disease (CVD) reduction in adults with no known underlying health conditions by undertaking a meta-analysis and systematic review of the current evidence. Materials and Methods: We performed a systematic search to identify Primary Prevention Randomized Controlled Trials (RCTs) that compared statins with a control group where CVD events or mortality were the primary end point. Identified RCTs were evaluated and classified into categories depending on relevance in order to determine which type of meta-analysis would be feasible. Results: No differences were observed between categories with the exception of relative risk for all CVD events combined which showed a 12% statistically significant difference favouring studies which were known to include participants without underlying health conditions. Strong negative correlations between number-need-to-treat (NNT) and LDL-C reduction were observed for all Coronary Heart Disease (CHD) outcomes combined and all CVD outcomes combined. Conclusions: This project highlights the need for further research on the effects of statins on participants who do not suffer from underlying health conditions, given that no such studies have been conducted.
Dying in the Margins: A Literature Review on End of Life in English Prisons
Authors: Visser Renske Claasje
Published: June 2021

This paper explores dying in English prisons. Whilst often conflated, death and dying are conceptually different. While there is increased attention given to the investigation of deaths in custody, and the impact of prison deaths on healthcare staff and custodial staff, little attention has been paid to the experience of dying people themselves. Post-death investigations tell us little about dying experiences of the dying. This paper reviewed the literature on dying in English prisons and highlights this clear gap in knowledge. Four types of dying will be discussed in this paper: (1) suicide, (2) dying in older age, (3) deaths post-release, and (4) COVID-19 deaths. The importance of providing good end-of-life care and palliative care in prison is acknowledged in the literature, but this only shows awareness of the needs of a particular part of the prison population. To understand the complexities and nuances of dying in prison, all voices need to be included in research, otherwise what is left post-death of a person who died in prison is a Fatal Incidence Report. More empirical research is needed to illuminate the diversity of prison deaths and the lived reality of those dying behind locked doors.
An Analysis of the Vulnerability of Two Common Deep Learning-Based Medical Image Segmentation Techniques to Model Inversion Attacks
Authors: Subbanna Nagesh , Wilms Matthias , Tuladhar Anup , Forkert Nils D.
Published: June 2021

Recent research in computer vision has shown that original images used for training of deep learning models can be reconstructed using so-called inversion attacks. However, the feasibility of this attack type has not been investigated for complex 3D medical images. Thus, the aim of this study was to examine the vulnerability of deep learning techniques used in medical imaging to model inversion attacks and investigate multiple quantitative metrics to evaluate the quality of the reconstructed images. For the development and evaluation of model inversion attacks, the public LPBA40 database consisting of 40 brain MRI scans with corresponding segmentations of the gyri and deep grey matter brain structures were used to train two popular deep convolutional neural networks, namely a U-Net and SegNet, and corresponding inversion decoders. Matthews correlation coefficient, the structural similarity index measure (SSIM), and the magnitude of the deformation field resulting from non-linear registration of the original and reconstructed images were used to evaluate the reconstruction accuracy. A comparison of the similarity metrics revealed that the SSIM is best suited to evaluate the reconstruction accuray, followed closely by the magnitude of the deformation field. The quantitative evaluation of the reconstructed images revealed SSIM scores of 0.73±0.12 and 0.61±0.12 for the U-Net and the SegNet, respectively. The qualitative evaluation showed that training images can be reconstructed with some degradation due to blurring but can be correctly matched to the original images in the majority of the cases. In conclusion, the results of this study indicate that it is possible to reconstruct patient data used for training of convolutional neural networks and that the SSIM is a good metric to assess the reconstruction accuracy.
Wavefront Restoration Technology of Dynamic Non-Uniform Intensity Distribution Based on Extreme Learning Machine
Authors: Lin Haiqi , He Xing , Wang Shuai , Yang Ping
Published: June 2021

Non-uniform intensity distribution of laser near-field beam results in the irregular shape of the spot in the wavefront sensor. The intensity of some sub-aperture spots may be too weak to be detected, and the accuracy of wavefront restoration is seriously affected. Therefore, an extreme learning machine method is proposed to realize high precision wavefront restoration under dynamic non-uniform intensity distribution. The simulation results show that this method has better accuracy of wavefront restoration than the classical modal algorithm under dynamic non-uniform intensity distribution. The root mean square error of the residual wavefront for the proposed method is only 2.9% of the initial value.
Anomaly Detection Using Signal Segmentation and One-Class Classification in Diffusion Process of Semiconductor Manufacturing
Authors: Chang Kyuchang , Yoo Youngji , Baek Jun-Geol
Published: June 2021

This paper proposes a new diagnostic method for sensor signals collected during semiconductor manufacturing. These signals provide important information for predicting the quality and yield of the finished product. Much of the data gathered during this process is time series data for fault detection and classification (FDC) in real time. This means that time series classification (TSC) must be performed during fabrication. With advances in semiconductor manufacturing, the distinction between normal and abnormal data has become increasingly significant as new challenges arise in their identification. One challenge is that an extremely high FDC performance is required, which directly impacts productivity and yield. However, general classification algorithms can have difficulty separating normal and abnormal data because of subtle differences. Another challenge is that the frequency of abnormal data is remarkably low. Hence, engineers can use only normal data to develop their models. This study presents a method that overcomes these problems and improves the FDC performance; it consists of two phases. Phase I has three steps: signal segmentation, feature extraction based on local outlier factors (LOF), and one-class classification (OCC) modeling using the isolation forest (iF) algorithm. Phase II, the test stage, consists of three steps: signal segmentation, feature extraction, and anomaly detection. The performance of the proposed method is superior to that of other baseline methods.
Radar Sensing for Activity Classification in Elderly People Exploiting Micro-Doppler Signatures Using Machine Learning
Authors: Taylor William , Dashtipour Kia , Shah Syed Aziz , Hussain Amir , Abbasi Qammer H. , Imran Muhammad A.
Published: June 2021

The health status of an elderly person can be identified by examining the additive effects of aging along with disease linked to it and can lead to ‘unstable incapacity’. This health status is determined by the apparent decline of independence in activities of daily living (ADLs). Detecting ADLs provides possibilities of improving the home life of elderly people as it can be applied to fall detection systems. This paper presents fall detection in elderly people based on radar image classification by examining their daily routine activities, using radar data that were previously collected for 99 volunteers. Machine learning techniques are used classify six human activities, namely walking, sitting, standing, picking up objects, drinking water and fall events. Different machine learning algorithms, such as random forest, K-nearest neighbours, support vector machine, long short-term memory, bi-directional long short-term memory and convolutional neural networks, were used for data classification. To obtain optimum results, we applied data processing techniques, such as principal component analysis and data augmentation, to the available radar images. The aim of this paper is to improve upon the results achieved using a publicly available dataset to further improve upon research of fall detection systems. It was found out that the best results were obtained using the CNN algorithm with principal component analysis and data augmentation together to obtain a result of 95.30% accuracy. The results also demonstrated that principal component analysis was most beneficial when the training data were expanded by augmentation of the available data. The results of our proposed approach, in comparison to the state of the art, have shown the highest accuracy.
Development of a Wide Area 3D Scanning System with a Rotating Line Laser
Authors: Lee Jaeho , Shin Hyunsoo , Lee Sungon
Published: June 2021

In a 3D scanning system, using a camera and a line laser, it is critical to obtain the exact geometrical relationship between the camera and laser for precise 3D reconstruction. With existing depth cameras, it is difficult to scan a large object or multiple objects in a wide area because only a limited area can be scanned at a time. We developed a 3D scanning system with a rotating line laser and wide-angle camera for large-area reconstruction. To obtain 3D information of an object using a rotating line laser, we must be aware of the plane of the line laser with respect to the camera coordinates at every rotating angle. This is done by estimating the rotation axis during calibration and then by rotating the laser at a predefined angle. Therefore, accurate calibration is crucial for 3D reconstruction. In this study, we propose a calibration method to estimate the geometrical relationship between the rotation axis of the line laser and the camera. Using the proposed method, we could accurately estimate the center of a cone or cylinder shape generated while the line laser was rotating. A simulation study was conducted to evaluate the accuracy of the calibration. In the experiment, we compared the results of the 3D reconstruction using our system and a commercial depth camera. The results show that the precision of our system is approximately 65% higher for plane reconstruction, and the scanning quality is also much better than that of the depth camera.
Joint Design of Colocated MIMO Radar Constant Envelope Waveform and Receive Filter to Reduce SINR Loss
Authors: Huang Liang , Deng Xiaofang , Zheng Lin , Qin Huiping , Qiu Hongbing
Published: June 2021

In this paper, we aim at the problem that MIMO radar’s target detection performance is greatly reduced in the complex multi-signal-dependent interferences environment. We propose a joint design method based on semidefinite relaxation (SDR), fractional programming and randomization technique (JD-SFR) and a joint design method based on coordinate descent (JD-CD) to solve the actual transmit waveform and receive filter bank directly to reduce the loss of strong interference to the output signal-to-interference-plus-noise ratio (SINR) of the radar system. Therefore, the maximization of output SINR is taken as the criterion of the optimization problem. The designed waveforms take into account the radar transmitter’s hardware requirements for constant envelope waveforms and impose similarity constraints on the waveforms. JD-SFR uses SDR, fractional programming and randomization technique to deal with the non-convex optimization problems encountered in the solution process. JD-CD transforms the optimization problem into a function of the phase of the waveform and then solves the transmit waveform based on CD. Compared with other methods, the proposed method has lower output SINR loss under strong power interference and forms deep nulls on the direction beampattern of multiple interference sources, which indicates that it has better anti-interference performance.
User Local Coordinate-Based Accompanying Robot for Human Natural Movement of Daily Life
Authors: Wu Hsiao-Kuan , Chen Po-Yin , Wu Hong-Yi , Yu Chung-Huang
Published: June 2021

Considering the trend of aging societies, accompanying technology can help frail, elderly individuals participate in daily activities. The ideal accompanying robot should accompany the user in a proper position according to the activity scenarios and context; the prerequisite is that the accompanying robot should quickly move to a designated position and closely maintain it regardless of the direction in which the user moves. This paper proposes a user local coordinate-based strategy to satisfy this need. As a proof of concept, a novel “string-pot” approach was utilized to measure the position difference between the robot and the target. We implemented the control strategy and assessed its performance in our gait lab. The results showed that the robot can follow the user in the designated position while the user performs forward, backward, and lateral movements, turning, and walking along a curve.
SafeDrive: Hybrid Recommendation System Architecture for Early Safety Predication Using Internet of Vehicles
Authors: Nouh Rayan , Singh Madhusudan , Singh Dhananjay
Published: June 2021

The Internet of vehicles (IoV) is a rapidly emerging technological evolution of Intelligent Transportation System (ITS). This paper proposes SafeDrive, a dynamic driver profile (DDP) using a hybrid recommendation system. DDP is a set of functional modules, to analyses individual driver’s behaviors, using prior violation and accident records, to identify driving risk patterns. In this paper, we have considered three synthetic data-sets for 1500 drivers based on their profile information, risk parameters information, and risk likelihood. In addition, we have also considered the driver’s historical violation/accident data-set records based on four risk-score levels such as high-risk, medium-risk, low-risk, and no-risk to predict current and future driver risk scores. Several error calculation methods have been applied in this study to analyze our proposed hybrid recommendation systems’ performance to classify the driver’s data with higher accuracy based on various criteria. The evaluated results help to improve the driving behavior and broadcast early warning alarm to the other vehicles in IoV environment for the overall road safety. Moreover, the propoed model helps to provide a safe and predicted environment for vehicles, pedestrians, and road objects, with the help of regular monitoring of vehicle motion, driver behavior, and road conditions. It also enables accurate prediction of accidents beforehand, and also minimizes the complexity of on-road vehicles and latency due to fog/cloud computing servers.
Carbonized Cotton Fabric-Based Flexible Capacitive Pressure Sensor Using a Porous Dielectric Layer with Tilted Air Gaps
Authors: Ko Yelin , Vu Chi Cuong , Kim Jooyong
Published: June 2021

Flexible and wearable pressure sensors have attracted significant attention owing to their roles in healthcare monitoring and human–machine interfaces. In this study, we introduce a wide-range, highly sensitive, stable, reversible, and biocompatible pressure sensor based on a porous Ecoflex with tilted air-gap-structured and carbonized cotton fabric (CCF) electrodes. The knitted structure of electrodes demonstrated the effectiveness of the proposed sensor in enhancing the pressure-sensing performance in comparison to a woven structure due to the inherent properties of naturally generated space. In addition, the presence of tilted air gaps in the porous elastomer provided high deformability, thereby significantly improving the sensor sensitivity compared to other dielectric structures that have no or vertical air gaps. The combination of knitted CCF electrodes and the porous dielectric with tilted air gaps achieved a sensitivity of 24.5 × 10−3 kPa−1 at 100 kPa, along with a wide detection range (1 MPa). It is also noteworthy that this novel method is low-cost, facile, scalable, and ecofriendly. Finally, the proposed sensor integrated into a smart glove detected human motions of grasping water cups, thus demonstrating its potential applications in wearable electronics.