bluuebunny/crossref_metadata_2025 huggingface dataset:
Preparation of Antioxidant and Antibacterial Chitosan Film from Periplaneta americana
Authors: Chen Sicong , Wei Xunfan , Sui Zhuoxiao , Guo Mengyuan , Geng Jin , Xiao Jinhua , Huang Dawei
Published: January 2021

Among different insects, the American cockroach (Periplaneta americana) has been bred in industrial scale successfully as a potential resource of protein, lipid, and antibacterial peptide. However, the application of its chitosan has not been studied widely, which has hindered the sufficient utilization of P. americana. In this paper, the chitosan from P. americana was separated, characterized, and processed into film (PaCSF) to examine its potential of being applied in food packaging. As the results of different characterizations showed, PaCSF was similar to shrimp chitosan film (SCSF). However, concerning the performances relating to food packaging, the two chitosan films were different. PaCSF contained more water (42.82%) than SCSF did, resulting in its larger thickness (0.08 mm). PaCSF could resist UV light more effectively than SCSF did. Concerning antioxidant activity, the DPPH radical scavenging ability of PaCSF increased linearly with time passing, reaching 72.46% after 8 h, which was better than that of SCSF. The antibacterial activity assay exhibited that PaCSF resisted the growth of Serratia marcescens and Escherichia coli more effectively than SCSF did. The results implied that P. americana chitosan could be a potential raw material for food packaging, providing a new way to develop P. americana.
Pollinators on Cowpea Vigna unguiculata: Implications for Intercropping to Enhance Biodiversity
Authors: Dingha Beatrice N. , Jackai Louis E. , Amoah Barbara A. , Akotsen-Mensah Clement
Published: January 2021

Pollinators are on the decline and loss of flower resources play a major role. This raises concerns regarding production of insect-pollinated crops and therefore food security. There is urgency to mitigate the decline through creation of farming systems that encourage flower-rich habitats. Cowpea is a crop that produces pollen and nectar attractive to pollinators. Twenty-four cowpea varieties were planted, and the number of pollinators were counted using three sampling methods: pan traps, sticky traps, and direct visual counts. Five pollinator types (honey bees, bumble bees, carpenter bees, wasps, and butterflies and moths), 11 and 16 pollinator families were recorded from direct visual counts, pan and sticky traps, respectively. Pollinator distribution varied significantly among varieties and sampling methods, with highest number on Penny Rile (546.0 ± 38.6) and lowest (214.8 ± 29.2) in Iron and Clay. Sticky traps accounted for 45%, direct visual counts (31%), and pan traps (23%) of pollinators. Pollinators captured by pan traps were more diverse than the other methods. The relationship between number of pollinators and number of flowers was significant (r2 = 0.3; p = 0.009). Cowpea can increase resources for pollinators and could be used to improve pollinator abundance and diversity in different farming systems.
The First Complete Mitochondrial Genome of Lachninae Species and Comparative Genomics Provide New Insights into the Evolution of Gene Rearrangement and the Repeat Region
Authors: Zhang Hui , Liu Qian , Lu Congcong , Deng Jun , Huang Xiaolei
Published: January 2021

Complete mitochondrial genomes are valuable resources for different research fields such as genomics, molecular evolution and phylogenetics. The subfamily Lachninae represents one of the most ancient evolutionary lineages of aphids. To date, however, no complete Lachninae mitogenome is available in public databases. Here we report the Stomaphis sinisalicis mitogenome, representing the first complete mitogenome of Lachninae. The S. sinisalicis mitogenome is consist of 13 protein-coding genes (PCGs), two rRNA genes (rRNAs), 22 tRNA genes (tRNAs), a control region and a large tandem repeat region. Strikingly, the mitogenome exhibits a novel, highly rearranged gene order between trnE and nad1 compared with that of other aphids. The presence of repeat region in the basal Lachninae may further indicate it is probably an ancestral feature of aphid mitogenomes. Collectively, this study provides new insights on mitogenome evolution and valuable data for future comparative studies across different insect lineages.
Use of a Managed Solitary Bee to Pollinate Almonds: Population Sustainability and Increased Fruit Set
Authors: Bosch Jordi , Osorio-Canadas Sergio , Sgolastra Fabio , Vicens Narcís
Published: January 2021

Osmia spp. are excellent orchard pollinators but evidence that their populations can be sustained in orchard environments and their use results in increased fruit production is scarce. We released an Osmia cornuta population in an almond orchard and measured its population dynamics, as well as visitation rates and fruit set at increasing distances from the nesting stations. Honeybees were 10 times more abundant than O. cornuta. However, the best models relating fruit set and bee visitation included only O. cornuta visitation, which explained 41% and 40% of the initial and final fruit set. Distance from the nesting stations explained 27.7% and 22.1% of the variability in initial and final fruit set. Of the 198 females released, 99 (54.4%) established and produced an average of 9.15 cells. Female population growth was 1.28. By comparing our results with those of previous O. cornuta studies we identify two important populational bottlenecks (female establishment and male-biased progeny sex ratios). Our study demonstrates that even a small population of a highly effective pollinator may have a significant impact on fruit set. Our results are encouraging for the use of Osmia managed populations and for the implementation of measures to promote wild pollinators in agricultural environments.
Population Dynamics of Aedes aegypti and Aedes albopictus in Two Rural Villages in Southern Mexico: Baseline Data for an Evaluation of the Sterile Insect Technique
Authors: Marina Carlos F. , Bond J. Guillermo , Hernández-Arriaga Kenia , Valle Javier , Ulloa Armando , Fernández-Salas Ildefonso , Carvalho Danilo O. , Bourtzis Kostas , Dor Ariane , Williams Trevor , Liedo Pablo
Published: January 2021

Indoor and outdoor ovitraps were placed in 15 randomly selected houses in two rural villages in Chiapas, southern Mexico. In addition, ovitraps were placed in five transects surrounding each village, with three traps per transect, one at the edge, one at 50 m, and another at 100 m from the edge of the village. All traps were inspected weekly. A transect with eight traps along a road between the two villages was also included. Population fluctuations of Aedes aegypti and Ae. albopictus were examined during 2016–2018 by counting egg numbers. A higher number of Aedes spp. eggs was recorded at Hidalgo village with 257,712 eggs (60.9%), of which 58.1% were present in outdoor ovitraps and 41.9% in indoor ovitraps, compared with 165,623 eggs (39.1%) collected in the village of Río Florido, 49.0% in outdoor and 51.0% in indoor ovitraps. A total of 84,047 eggs was collected from ovitraps placed along transects around Río Florido, compared to 67,542 eggs recorded from transects around Hidalgo. Fluctuations in egg counts were associated with annual variation in precipitation, with 2.3 to 3.2-fold more eggs collected from ovitraps placed in houses and 4.8 to 5.1-fold more eggs in ovitraps from the surrounding transects during the rainy season than in the dry season, respectively. Aedes aegypti was the dominant species during the dry season and at the start of the rainy season in both villages. Aedes albopictus populations were lower for most of the dry season, but increased during the rainy season and predominated at the end of the rainy season in both villages. Aedes albopictus was also the dominant species in the zones surrounding both villages. The numbers of eggs collected from intradomiciliary ovitraps were strongly correlated with the numbers of eggs in peridomiciliary ovitraps in both Río Florido (R2adj = 0.92) and Hidalgo (R2adj = 0.94), suggesting that peridomiciliary sampling could provide an accurate estimate of intradomiciliary oviposition by Aedes spp. in future studies in these villages. We conclude that the feasibility of sterile insect technique (SIT)-based program of vector control could be evaluated in the isolated Ae. aegypti populations in the rural villages of our baseline study.
Ballistic Penetration Analysis of Soft Laminated Composites Using Sublaminate Mesoscale Modeling
Authors: Chricker Raz , Mustacchi Shaul , Massarwa Eyass , Eliasi Rami , Aboudi Jacob , Haj-Ali Rami
Published: January 2021

Ballistic impact mitigation requires the development of protective armor applications from composite material systems with good energy absorption and penetration resistance against threats, e.g., metallic projectiles. In this aim, high-strength and high-stiffness soft fibrous composite materials (such as ultra-high molecular weight polyethylene—UHMWPE) are often used. The high specific strength feature is one of the main reasons for using these soft composite systems in ballistic impact applications. In the present investigation, experimental and computational finite element (FE) studies were carried out to investigate the ballistic behaviors of these soft layered composite targets. To this end, a new FE multi-scale analysis framework for ballistic simulations is offered. The proposed analysis presents a new meso-scale sublaminate material model, which is applied to Dyneema® cross-ply laminate in order to predict its behavior under ballistic impact. The sublaminate model is implemented within an explicit dynamic FE code to simulate the continuum response in each element. The sublaminate model assumes a through-thickness periodic stacking of repeated cross-ply configuration. In addition, a cohesive layer is introduced in the sublaminate model in order to simulate the delamination effect leading to the subsequent degradation and deletion of the elements. This new approach eliminates the widely used costly computational approach of using explicit cohesive elements installed at pre-specified potential delamination paths between the layers. Furthermore, in-plane damage modes (such as fiber tensile, and out-of-plane shearing) are also accounted for by employing failure criteria and strain-softening. The obtained quantitative results of ballistic impact simulations show good correlation when compared to a relatively wide range of experiments. Moreover, the simulations include evidence of capturing the main energy absorption mechanisms under high-velocity impact. The proposed modeling approach can be used as a useful armor design tool.
Mechanical Consequences of Dynamically Loaded NiTi Wires under Typical Actuator Conditions in Rehabilitation and Neuroscience
Authors: Çakmak Umut D. , Major Zoltán , Fischlschweiger Michael
Published: January 2021

In the field of rehabilitation and neuroscience, shape memory alloys play a crucial role as lightweight actuators. Devices are exploiting the shape memory effect by transforming heat into mechanical work. In rehabilitation applications, dynamic loading of the respective device occurs, which in turn influences the mechanical consequences of the phase transforming alloy. Hence in this work, dynamic thermomechanical material behavior of temperature-triggered phase transforming NiTi shape memory alloy (SMA) wires with different chemical compositions and geometries was experimentally investigated. Storage modulus and mechanical loss factor of NiTi alloys at different temperatures and loading frequencies were analyzed under force-controlled conditions. Counterintuitive storage modulus- and loss factor-dependent trends regarding the loading frequency dependency of the mechanical properties on the materials’ composition and geometry were, hence, obtained. It was revealed that loss factors showed a pronounced loading frequency dependency, whereas the storage modulus was not affected. It was shown that force-controlled conditions led to a lower storage modulus than expected. Furthermore, it turned out that a simple empirical relation could capture the characteristic temperature dependency of the storage modulus, which is an important input relation for modeling the rehabilitation device behavior under different dynamic and temperature loading conditions, taking directly into account the material behavior of the shape memory alloy.
An Innovative Successive Approximation Register Analog-to-Digital Converter for a Nine-Axis Sensing System
Authors: Lin Chih-Hsuan , Wen Kuei-Ann
Published: January 2021

With nine-axis sensing systems in 5G smartphones, mobile power consumption has become increasingly important, and ultra-low-power (ULP) sensor circuits can decrease power consumption to tens of microwatts. This paper presents an innovative successive approximation register analog-to-digital converter, which comprises fine (three most significant bits (MSBs) plus course conversion (11 least significant bits (LSBs)) capacitive digital-to-analog converters (CDACs), ULP, four-mode reconfigurable resolution (9, 10, 11, or 12 bits), an internally generated clock, meta-detection, the switching base midpoint voltage (Vm) (SW-B-M), bit control logic, multi-phase control logic, fine (three MSBs) plus course conversion (11 LSBs) switch control logic, phase control logic, and an input signal plus negative voltage (VI + NEG) voltage generator. Then, the mechanism of the discrete Fourier transform (DFT)-based calibration is applied. The scalable voltage technique was used, and the analog/digital voltage was Vanalog (1.5 V) and Vdigital (0.9 V) to meet the specifications of the nine-axis ULP sensing system. The CDACs can reconfigure four-mode resolutions, 9–12 bits, for use in nine-axis sensor applications. The corresponding dynamic signal-to-noise and distortion ratio performance was 50.78, 58.53, 62.42, and 66.51 dB. In the 12-bit mode, the power consumption of the ADC was approximately 2.7 μW, and the corresponding figure of merit (FoM) was approximately 30.5 fJ for each conversion step.
Model Uncertainty for Settlement Prediction on Axially Loaded Piles in Hydraulic Fill Built in Marine Environment
Authors: Bueno Aguado Manuel , Escolano Sánchez Félix , Sanz Pérez Eugenio
Published: January 2021

Model uncertainty is present in many engineering problems but particularly in those involving geotechnical behavior of pile foundation. A wide range of soil conditions together with simplified numerical models makes it a constant necessity to review the accuracy of the predictions. In this paper, the outputs of some seventy (70) pile axially-loaded tests have been reviewed with a classic numerical model to assess pile deformation. Probabilistic approach has been used to quantify uncertainties coming from soil tests, statistic uncertainty and also from the model itself. In this way, a critical review of the prediction method and a way to quantify its uncertainty is presented. The method is intended to be used in a wide range of engineering problems.
Candida parapsilosis Colony Morphotype Forecasts Biofilm Formation of Clinical Isolates
Authors: Gómez-Molero Emilia , De-la-Pinta Iker , Fernández-Pereira Jordan , Groß Uwe , Weig Michael , Quindós Guillermo , de Groot Piet W. J. , Bader Oliver
Published: January 2021

Candida parapsilosis is a frequent cause of fungal bloodstream infections, especially in critically ill neonates or immunocompromised patients. Due to the formation of biofilms, the use of indwelling catheters and other medical devices increases the risk of infection and complicates treatment, as cells embedded in biofilms display reduced drug susceptibility. Therefore, biofilm formation may be a significant clinical parameter, guiding downstream therapeutic choices. Here, we phenotypically characterized 120 selected isolates out of a prospective collection of 215 clinical C. parapsilosis isolates, determining biofilm formation, major emerging colony morphotype, and antifungal drug susceptibility of the isolates and their biofilms. In our isolate set, increased biofilm formation capacity was independent of body site of isolation and not predictable using standard or modified European Committee on Antimicrobial Susceptibility Testing (EUCAST) drug susceptibility testing protocols. In contrast, biofilm formation was strongly correlated with the appearance of non-smooth colony morphotypes and invasiveness into agar plates. Our data suggest that the observation of non-smooth colony morphotypes in cultures of C. parapsilosis may help as an indicator to consider the initiation of anti-biofilm-active therapy, such as the switch from azole- to echinocandin- or polyene-based strategies, especially in case of infections by potent biofilm-forming strains.
Expanding the Knowledge on the Skillful Yeast Cyberlindnera jadinii
Authors: Sousa-Silva Maria , Vieira Daniel , Soares Pedro , Casal Margarida , Soares-Silva Isabel
Published: January 2021

Cyberlindnera jadinii is widely used as a source of single-cell protein and is known for its ability to synthesize a great variety of valuable compounds for the food and pharmaceutical industries. Its capacity to produce compounds such as food additives, supplements, and organic acids, among other fine chemicals, has turned it into an attractive microorganism in the biotechnology field. In this review, we performed a robust phylogenetic analysis using the core proteome of C. jadinii and other fungal species, from Asco- to Basidiomycota, to elucidate the evolutionary roots of this species. In addition, we report the evolution of this species nomenclature over-time and the existence of a teleomorph (C. jadinii) and anamorph state (Candida utilis) and summarize the current nomenclature of most common strains. Finally, we highlight relevant traits of its physiology, the solute membrane transporters so far characterized, as well as the molecular tools currently available for its genomic manipulation. The emerging applications of this yeast reinforce its potential in the white biotechnology sector. Nonetheless, it is necessary to expand the knowledge on its metabolism, regulatory networks, and transport mechanisms, as well as to develop more robust genetic manipulation systems and synthetic biology tools to promote the full exploitation of C. jadinii.
Fungal Treatment for the Valorization of Technical Soda Lignin
Authors: Daou Mariane , Farfan Soto Clementina , Majira Amel , Cézard Laurent , Cottyn Betty , Pion Florian , Navarro David , Oliveira Correia Lydie , Drula Elodie , Record Eric , Raouche Sana , Baumberger Stéphanie , Faulds Craig B.
Published: January 2021

Technical lignins produced as a by-product in biorefinery processes represent a potential source of renewable carbon. In consideration of the possibilities of the industrial transformation of this substrate into various valuable bio-based molecules, the biological deconstruction of a technical soda lignin by filamentous fungi was investigated. The ability of three basidiomycetes (Polyporus brumalis, Pycnoporus sanguineus and Leiotrametes menziesii) to modify this material, the resultant structural and chemical changes, and the secreted proteins during growth on this substrate were investigated. The three fungi could grow on the technical lignin alone, and the growth rate increased when the media were supplemented with glucose or maltose. The proteomic analysis of the culture supernatants after three days of growth revealed the secretion of numerous Carbohydrate-Active Enzymes (CAZymes). The secretomic profiles varied widely between the strains and the presence of technical lignin alone triggered the early secretion of many lignin-acting oxidoreductases. The secretomes were notably rich in glycoside hydrolases and H2O2-producing auxiliary activity enzymes with copper radical oxidases being induced on lignin for all strains. The lignin treatment by fungi modified both the soluble and insoluble lignin fractions. A significant decrease in the amount of soluble higher molar mass compounds was observed in the case of P. sanguineus. This strain was also responsible for the modification of the lower molar mass compounds of the lignin insoluble fraction and a 40% decrease in the thioacidolysis yield. The similarity in the activities of P. sanguineus and P. brumalis in modifying the functional groups of the technical lignin were observed, the results suggest that the lignin has undergone structural changes, or at least changes in its composition, and pave the route for the utilization of filamentous fungi to functionalize technical lignins and produce the enzymes of interest for biorefinery applications.
Filamentous Fungal Infections in a Tertiary Care Setting: Epidemiology and Clinical Outcome
Authors: Van den Nest Miriam , Wagner Gernot , Riesenhuber Martin , Dolle Constantin , Presterl Elisabeth , Gartlehner Gerald , Moertl Deddo , Willinger Birgit
Published: January 2021

Information on the distribution of filamentous fungal pathogens, which cause potential life-threatening invasive infections mostly in immunocompromised persons, is of great importance. The aim of this study was to evaluate the epidemiology and clinical outcome in patients with infections due to filamentous fungi at the University Hospital of Vienna, Austria. We conducted a retrospective observational study and consecutively included patients of any age with filamentous fungal infections between 2009 and 2017. The classification for probable and proven invasive filamentous fungal infections was based on the European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group (EORTC) criteria or the expert opinion of an experienced clinical mycologist. We included 129 patients (median age: 52 years; 47.3% female) with episodes of 101 proven and probable invasive and 35 localized filamentous fungal infections (16 sinus, 14 eye, one ear, and four deep cutaneous). Aspergillus fumigatus alone accounted for 50.3% of the fungi, which was followed by the Mucorales group (13.7%) and Fusarium spp. (8.5%). Diagnosis was mainly based on culture findings. The lung was the most frequent site of infection. The 30-day and 90-day overall mortality of invasive fungal infections was 30.2% and 42.7%, respectively. We observed a high all-cause mortality among patients with invasive filamentous fungal infections. Prospective data collection in a nationwide registry would be necessary to provide important information on surveillance to clinicians and other decision-makers.
Real-Time Implementation of EEG Oscillatory Phase-Informed Visual Stimulation Using a Least Mean Square-Based AR Model
Authors: Shakeel Aqsa , Onojima Takayuki , Tanaka Toshihisa , Kitajo Keiichi
Published: January 2021

It is a technically challenging problem to assess the instantaneous brain state using electroencephalography (EEG) in a real-time closed-loop setup because the prediction of future signals is required to define the current state, such as the instantaneous phase and amplitude. To accomplish this in real-time, a conventional Yule–Walker (YW)-based autoregressive (AR) model has been used. However, the brain state-dependent real-time implementation of a closed-loop system employing an adaptive method has not yet been explored. Our primary purpose was to investigate whether time-series forward prediction using an adaptive least mean square (LMS)-based AR model would be implementable in a real-time closed-loop system or not. EEG state-dependent triggers synchronized with the EEG peaks and troughs of alpha oscillations in both an open-eyes resting state and a visual task. For the resting and visual conditions, statistical results showed that the proposed method succeeded in giving triggers at a specific phase of EEG oscillations for all participants. These individual results showed that the LMS-based AR model was successfully implemented in a real-time closed-loop system targeting specific phases of alpha oscillations and can be used as an adaptive alternative to the conventional and machine-learning approaches with a low computational load.
Association Analysis in Young and Middle-Aged Mothers—Relation between Expression of Cardiovascular Disease Associated MicroRNAs and Abnormal Clinical Findings
Authors: Hromadnikova Ilona , Kotlabova Katerina , Krofta Ladislav
Published: January 2021

The principal goal of the study was to map common postpartal alterations in gene expression of microRNAs associated with diabetes/cardiovascular/cerebrovascular diseases induced by most frequently occurring pregnancy-related complications (gestational hypertension, preeclampsia, fetal growth restriction, gestational diabetes mellitus, preterm prelabor rupture of membranes, or spontaneous preterm birth). In addition, the association analyses between individual abnormal clinical findings (overweight/obesity, central obesity, hypertension, on blood pressure treatment, history of infertility treatment, actual hormonal contraceptive use, the presence of trombophilic gene mutations, actual smoking status, increased serum levels of total cholesterol, HDL (high density lipoprotein) cholesterol, LDL (low density lipoprotein) cholesterol, triglycerides, lipoprotein A, CRP (C-reactive protein), and uric acid, and increased plasma levels of homocysteine) and microRNA expression levels were performed in mothers with respect/regardless to previous course of gestation. The prior exposure to gestational hypertension, preeclampsia, fetal growth restriction, gestational diabetes mellitus, preterm prelabor rupture of membranes, or spontaneous preterm birth caused that a significant proportion of mothers (52.42% at 90.0% specificity) had substantially altered microRNA expression profile, which might originate lifelong cardiovascular risk. 26 out of 29 tested microRNAs were up-regulated in mothers with a history of such complicated pregnancies. MicroRNA expression profiles were also able to differentiate between mothers with normal and abnormal clinical findings (BMI (body mass index), waist circumference, systolic blood pressure, on blood pressure treatment, history of infertility treatment, and the presence of trombophilic gene mutations) irrespective of previous course of gestation. The treatment of hypertension even intensified upregulation of some microRNAs (miR-24-3p, and miR-342-3p) already present in women after complicated pregnancies. Newly, the presence of overweight/obesity (miR-155-5p), systolic hypertension (miR-92a-3p, and miR-210-3p), treatment for infertility (miR-155-5p), and treatment for hypertension (miR-210-3p) induced upregulation of several microRNAs. In general, mothers after complicated pregnancies are at increased risk of development of cardiovascular complications. Especially those mothers indicated to have postpartally altered microRNA expression profiles might be considered as a highly risky group that would benefit from dispensarization and implementation of primary prevention strategies.
Reference Prices and Turnover: Evidence from Small-Capitalization Stocks
Authors: Pandey Ashish
Published: January 2021

A large amount of literature in the field of social psychology and product pricing discusses the role of reference prices in affecting buyer’s price perception and purchase intention. Reference price denotes a standard against which the consumer compares the offer price of a product. In this paper, we investigate whether reference prices play any role in affecting the trading decision of stock market investors. We use firm-level, fixed-effect panel data methodology to empirically investigate whether investors respond to a violation of their internalized reference price range by executing a trading decision. Our results, based on a sample of Indian firms with small capitalization, show that investors respond to a violation of their internalized reference price range by executing a trading decision. However, consistent with the prior findings that investors suffer from myopic loss aversion, they continue to hold the positions when the reference price range is violated on the downside but sell stocks that have violated the high point of the reference price range. Our findings are robust for the reference price ranges that are constructed using the prior day’s trading prices, prior week’s trading prices, and prior year’s trading prices. The portfolio managers can develop a better understanding of expected trading intensity by incorporating reference price range in their models. The policymakers can use our results to find ways to improve the liquidity and efficiency of financial markets.
Professionalization of Online Gaming? Theoretical and Empirical Analysis for a Monopoly-Holding Platform
Authors: Ribeiro Vitor Miguel , Bao Lei
Published: January 2021

We analyze the private equilibrium of a two-sided market representing the online gaming industry under a principal-agent model. A monopoly-holding platform hires a manager to attract new members from both sides of the market while considering uncertainty on the adhesion of viewers and online gamers. First, we mathematically demonstrate that increasing cross-group network externalities can decrease the platform’s profit, which contradicts a canonical result from the field of two-sided markets. Moreover, knowing that the intermediary’s goal is aligned with the private interest of online gamers, machine learning models empirically show that the main theoretical outcome is observed in reality due to the presence of heterogeneous indirect network effects in online gaming activities. Second, we conclude that social welfare can be either harmed or improved for increasing cross-group network externalities, which means that the professionalization of online gaming may or may not be legitimized depending on the value taken by exogenous parameters related to the platform’s uncertainty on the number of agents that get on board, risk aversion of viewers, and royalty rate applied to online gamers. Finally, a discussion based on 2020 facts is provided and several policy recommendations are formulated to ensure the persistence of best regulatory practices.
Quality-of-Life Impairment among Patients with Hidradenitis Suppurativa: A Cross-Sectional Study of 1795 Patients
Authors: Krajewski Piotr K. , Matusiak Łukasz , von Stebut Esther , Schultheis Michael , Kirschner Uwe , Nikolakis Georgios , Szepietowski Jacek C.
Published: January 2021

The chronic, inflammatory skin disorder hidradenitis suppurativa (HS) is associated well documented negative influences on patients’ quality of life (QoL). The aim of this study was to present more robust data on patients’ QoL impairment by demographic data and its correlation with well-known HS risk factors on a cohort of 1795 German patients. The instrument used for measuring QoL in this study was the Dermatology Life Quality Index (DLQI). Overall, patients reported a very large effect of HS on their QoL (mean DLQI: 13.2 ± 8.1 points), and 22% of the analyzed population even reported to consider the effect as extremely large. Women tended to experience significantly higher impairment than men (p < 0.001). QoL impairment correlated positively with pain (r = 0.581, p < 0.001), HS severity (measured by the International Hidradenitis Suppurativa Severity Score System (IHS4)) as well as Hurley. Neck involvement tended to decrease QoL significantly more than any other location (14.7 ± 8.3 points). This study confirms the enormous influence of HS on patients’ QoL in a large cohort. Knowledge of QoL impairment in such patients is crucial for proper understanding and holistic management of this disease.
A Flow Stress Model of 300M Steel for Isothermal Tension
Authors: Chen Rongchuang , Zhang Shiyang , Liu Xianlong , Feng Fei
Published: January 2021

To investigate the effect of hot working parameters on the flow behavior of 300M steel under tension, hot uniaxial tensile tests were implemented under different temperatures (950 °C, 1000 °C, 1050 °C, 1100 °C, 1150 °C) and strain rates (0.01 s−1, 0.1 s−1, 1 s−1, 10 s−1). Compared with uniaxial compression, the tensile flow stress was 29.1% higher because dynamic recrystallization softening was less sufficient in the tensile stress state. The ultimate elongation of 300M steel increased with the decrease of temperature and the increase of strain rate. To eliminate the influence of sample necking on stress-strain relationship, both the stress and the strain were calibrated using the cross-sectional area of the neck zone. A constitutive model for tensile deformation was established based on the modified Arrhenius model, in which the model parameters (n, α, Q, ln(A)) were described as a function of strain. The average deviation was 6.81 MPa (6.23%), showing good accuracy of the constitutive model.
High Strain Rate Response of In-Situ TiB2/7055 Composite by Taylor Impact
Authors: Li Hengfu , Yu Zhenyu , Rong Peng , Wu Yi , Hui Xulong , Zhang Fengguo , Chen Zhe , Wang Haowei
Published: January 2021

The high strain rate deformation behavior and microstructure evolution of in situ TiB2 particle reinforced Al-Zn-Mg-Cu composite were investigated by means of Taylor impact. The dynamic tests were performed at three different impact velocities. Under three different velocities, no obvious shear failure occurred in the composite, indicating a good impact resistance. Compared to the quasi-static compression test, the dynamic yield strength increased obviously with the rise of velocity, even more than 1 GPa. The dislocation multiplication, phonon drag effect and ceramic reinforcement increased the flow stress of composite. Fine, equiaxed grain structure developed after impact, resulting from grain fragmentation or dynamic recrystallization. Finite element simulation of Taylor impact was qualitatively in agreement with the experiments, which was useful to elucidate the formation of equiaxed grain structure.
Formaldehyde Emissions from Wooden Toys: Comparison of Different Measurement Methods and Assessment of Exposure
Authors: Even Morgane , Wilke Olaf , Kalus Sabine , Schultes Petra , Hutzler Christoph , Luch Andreas
Published: January 2021

Formaldehyde is considered as carcinogenic and is emitted from particleboards and plywood used in toy manufacturing. Currently, the flask method is frequently used in Europe for market surveillance purposes to assess formaldehyde release from toys, but its concordance to levels measured in emission test chambers is poor. Surveillance laboratories are unable to afford laborious and expensive emission chamber testing to comply with a new amendment of the European Toy Directive; they need an alternative method that can provide reliable results. Therefore, the application of miniaturised emission test chambers was tested. Comparisons between a 1 m3 emission test chamber and 44 mL microchambers with two particleboards over 28 days and between a 24 L desiccator chamber and the microchambers with three puzzle samples over 10 days resulted in a correlation coefficient r2 of 0.834 for formaldehyde at steady state. The correlation between the results obtained in microchambers vs. flask showed a high variability over 10 samples (r2: 0.145), thereby demonstrating the error-proneness of the flask method in comparison to methods carried out under ambient parameters. An exposure assessment was also performed for three toy puzzles: indoor formaldehyde concentrations caused by puzzles were not negligible (up to 8 µg/m3), especially when more conservative exposure scenarios were considered.
Functional Method of Designing Self-Compacting Concrete
Authors: Rudnicki Tomasz
Published: January 2021

The article presents a new functional method of designing self-compacting concrete (SCC). The assumptions of the functional method of designing self-compacting concrete were based on the double coating assumption (i.e., it was assumed that the grains of coarse aggregate were coated with a layer of cement mortar, whereas the grains of sand with cement paste). The proposed method is composed of four stages, each of which is responsible for the selection of a different component of the concrete mix. The proposed designing procedure takes into consideration such a selection of the mineral skeleton in terms of the volumetric saturation of the mineral skeleton, which prevents the blocking of aggregate grains, and the designed liquid phase demonstrated high structural viscosity and low yield stress. The performed experimental studies, the simulation of the elaborated mathematical model fully allowed for the verification of the theoretical assumptions that are the basis for the development of the method of designing self-compacting concrete.
Effects of Different Types of Fibers on the Physical and Mechanical Properties of MICP-Treated Calcareous Sand
Authors: Zhao Jitong , Tong Huawei , Shan Yi , Yuan Jie , Peng Qiuwang , Liang Junling
Published: January 2021

Microbial-induced calcite precipitation (MICP) has been a promising method to improve geotechnical engineering properties through the precipitation of calcium carbonate (CaCO3) on the contact and surface of soil particles in recent years. In the present experiment, water absorption and unconfined compressive strength (UCS) tests were carried out to investigate the effects of three different fiber types (glass fiber, polyester fiber, and hemp fiber) on the physical and mechanical properties of MICP-treated calcareous sand. The fibers used were at 0%, 0.10%, 0.15%, 0.20%, 0.25%, 0.30%, 0.35%, and 0.40% relative to the weight of the sand. The results showed that the failure strain and ductility of the samples could be improved by adding fibers. Compared to biocemented sand (BS), the water absorption of these three fiber-reinforced biocemented sands were, respectively, decreased by 11.60%, 21.18%, and 7.29%. UCS was, respectively, increased by 24.20%, 60.76%, and 6.40%. Polyester fiber produced the best effect, followed by glass fiber and hemp fiber. The optimum contents of glass fiber and polyester fiber were 0.20% and 0.25%, respectively. The optimum content of hemp fiber was within the range of 0.20–0.25%. Light-emitting diode (LED) microscope and scanning electron microscope (SEM) images lead to the conclusion that only a little calcite precipitation had occurred around the hemp fiber, leading to a poor bonding effect compared to the glass and polyester fibers. It was therefore suggested that polyester fiber should be used to improve the properties of biocemented sand.
Binary Self-Assembly of Nanocolloidal Arrays using Concurrent and Sequential Spin Coating Techniques
Authors: Shen Shih-Jyun , Lee Demei , Wu Yu-Chen , Liu Shih-Jung
Published: January 2021

This paper reports the binary colloid assembly of nanospheres using spin coating techniques. Polystyrene spheres with sizes of 900 and 100 nm were assembled on top of silicon substrates utilizing a spin coater. Two different spin coating processes, namely concurrent and sequential coatings, were employed. For the concurrent spin coating, 900 and 100 nm colloidal nanospheres of latex were first mixed and then simultaneously spin coated onto the silicon substrate. On the other hand, the sequential coating process first created a monolayer of a 900 nm nanosphere array on the silicon substrate, followed by the spin coating of another layer of a 100 nm colloidal array on top of the 900 nm array. The influence of the processing parameters, including the type of surfactant, spin speed, and spin time, on the self-assembly of the binary colloidal array were explored. The empirical outcomes show that by employing the optimal processing conditions, binary colloidal arrays can be achieved by both the concurrent and sequential spin coating processes.
Exploring the Hydrogen-Induced Amorphization and Hydrogen Storage Reversibility of Y(Sc)0.95Ni2 Laves Phase Compounds
Authors: Zhao Shiqian , Wang Hui , Liu Jiangwen
Published: January 2021

Rare-earth-based AB2-type compounds with Laves phase structure are readily subject to hydrogen-induced amorphization and disproportionation upon hydrogenation. In this work, we conducted the Sc alloying on Y0.95Ni2 to improve its hydrogen storage properties. The results show that the amorphization degree of Y0.95Ni2 deepens with the increasing hydrogenation time, pressure, and temperature. The Y(Sc)0.95Ni2 ternary compounds show a significant improvement in reversibility and dehydriding thermodynamics due to the reduced atomic radius ratio RA/RB and cell volume. Hydrogen-induced amorphization is fully eliminated in the Y0.25Sc0.7Ni2. The Y0.25Sc0.7Ni2 delivers a reversible hydrogen storage capacity of 0.94 wt.% and the dissociation pressure of 0.095 MPa at the minimum dehydrogenation temperature of 100 °C.
Response of Novel Functionally-Graded Prepacked Aggregate Fibrous Concrete against Low Velocity Repeated Projectile Impacts
Authors: Prasad Nandhu , Murali Gunasekaran , Fediuk Roman , Vatin Nikolai , Karelina Maria
Published: January 2021

Preplaced Aggregate Fibrous Concrete (PAFC) is a newly minted composite that has recently become more popular. The production of PAFC involves two essential processes; first, the fibres and coarse aggregate were filled into the empty framework to form the first layer of a natural skeleton, followed by grout injecting. A cement grout fills the voids in the first layer skeleton with slight compaction. This process is repeated to complete the remaining layers; hence, a type of Functionally-graded Preplaced Aggregate Fibrous Concrete (FPAFC) is obtained. The most recent studies revealed that the literature regarding the high-velocity projectile impact on fibrous concrete is well documented; however, the low-velocity repeated projectile impact on PAFC is still unexplored and needs particular emphasis. This research aims to investigate the FPAFC made with a new type of steel and polypropylene fibres against low-velocity projectile impact to fill this research gap. In the current study, twelve mixes were prepared with mono and hybrid combinations of fibres for pioneering the possible utilization of fibres in FPAFC. The maximum fibre dosage in this study is limited to 2.4%. The projectile impact resistance of FPAFC was assessed in line with penetration depth, front and rear damage surface area, weight loss, damage ratio and failure pattern. Additionally, a simplified analytical model was introduced to compute the ejected composite mass from the tested specimens. The results revealed that the addition of steel fibre in a single layer FPAFC exhibited an increasing compressive strength trend compared to the two/three-layered FPAFC. Furthermore, increasing the dosage of fibre at the bottom and top layers of FPAFC with a hybrid combination alleviates the spalling with an increasing number of impacts. The results from this research offer the reference information for more detailed research and studies of FPAFC under low-velocity projectile impact.
Independently Tunable Multipurpose Absorber with Single Layer of Metal-Graphene Metamaterials
Authors: Han Chen , Zhong Renbin , Liang Zekun , Yang Long , Fang Zheng , Wang Yiqing , Ma Anchen , Wu Zhenhua , Hu Min , Liu Diwei , Liu Shenggang
Published: January 2021

This paper reports an independently tunable graphene-based metamaterial absorber (GMA) designed by etching two cascaded resonators with dissimilar sizes in the unit cell. Two perfect absorption peaks were obtained at 6.94 and 10.68 μm with simple single-layer metal-graphene metamaterials; the peaks show absorption values higher than 99%. The mechanism of absorption was analyzed theoretically. The independent tunability of the metamaterial absorber (MA) was realized by varying the Fermi level of graphene under a set of resonators. Furthermore, multi-band and wide-band absorption were observed by the proposed structure upon increasing the number of resonators and resizing them in the unit cell. The obtained results demonstrate the multipurpose performance of this type of absorber and indicate its potential application in diverse applications, such as solar energy harvesting and thermal absorbing.
Recovery of Palladium(II) and Platinum(IV) in Novel Extraction Systems
Authors: Wiecka Zuzanna , Rzelewska-Piekut Martyna , Wojciechowska Irmina , Wieszczycka Karolina , Regel-Rosocka Magdalena
Published: January 2021

Recovery of platinum group metals (PGM) from complex aqueous solutions generated as a result of leaching of various spent materials (e.g., spent automotive converters) is a vital issue in the context of the circular economy. In this study pyridinium derivatives containing an imidoamide or imine moiety (i.e., 3-[1-(2-ethylhexyloxyimine)methane]-1-propylpyridinium chloride, 3-[1-(decyloxyimine)methane]-1-propylpyridinium chloride, 3-[1-(decyloxyimine)ethane]-1-propylpyridinium chloride and 4-[1-amine(2-ethylhexyloxyimine)]-1-propylpyridinium chloride) are proposed as novel extractants for recovery of palladium(II) and platinum(IV) from model chloride aqueous solutions. The results of liquid-liquid extraction from one-component solutions of palladium(II) or platinum(IV) showed that quaternary pyridinium salts can be used as effective extractants for platinum metal ions. Moreover, PGM extraction from a two-component mixture proved no evident selectivity in the transfer of one of the metal ions to the organic phase. As the best extractant among the investigated ones, D3EI-PrCl (with straight alkyl chain at substituent) can be pointed out, however, problems with effective stripping or phase disengagement after stripping should be indicated as a drawback of the organic phases used. Further investigation should focus on the improvement of the organic phase properties (e.g., increase in hydrophobicity of the extractants and addition of an organic phase modifier) towards stripping efficiency.
The Numerical and Experimental Investigation of Particle Size Distribution Produced by an Electrical Discharge Process
Authors: Lin Faming , Liu Yifan , Li Xianglong , Bai Congqiang
Published: January 2021

The vague influence of thermal action of electrical discharge on size distribution of metallic powders hinders the adjustability of powder quality. Due to the small gap, short discharge on-time, uncertain discharge point, and strong light interference, direct observation of preparation is difficult to carry out. Herein, the multi-physics coupling finite element method (FEM) was applied to numerically investigate the relationship between size distribution and thermal action. Through modeling of thermal transformation and heat distribution on the surface of electrode, temperature of the electrode is found to be decided by the latent heat and the distribution of heat point obeys the normal distribution, which corresponds with experimental results. Finally, the vapor film to droplet fragmentation theory was proposed to explain the phenomenon of normal distribution. The research results provide theoretical support for the preparation of metallic powder by electrical discharge, and also play a guiding role in optimizing the process parameters in the actual preparation process to tune the size distribution.
Nanoindentation and Hierarchy Structure of the Bovine Hoof Wall
Authors: Wang Bingfeng , Huang Yiyu , Zhou Bingqing , Li Wenshu , Chen Haoyu
Published: January 2021

The bovine hoof wall with an α-keratin structure protects the bovine foot from impact loads when the cattle are running. Reduced modulus, hardness and creep behavior of the bovine hoof wall have been investigated by a nanoindentation technique. The average reduced modulus of the Transverse Direction (TD) specimens from the outside to inside wall is 3.76 and 2.05 GPa, respectively, while the average reduced modulus of the Longitudinal Direction (LD) specimens from the outside to inside wall is 4.54 and 3.22 GPa, respectively. Obviously, the orientation and the position of the bovine hoof wall have a significant influence on its mechanical properties. The use of the generalized Voigt–Kelvin model can make a good prediction of creep stage. Mechanical properties of the LD specimens are stronger than those of the TD specimens. The bovine hoof wall has a layered structure, which can effectively absorb the energy released by the crack propagation and passivate the crack tip. Therefore, a kind of structural model was designed and fabricated by three-dimensional printing technology, which has a 55% performance improvement on fracture toughness. It is believed that the reported results can be useful in the design of new bionic structure materials which may be used in motorcycle helmets and athletes’ protective equipment to achieve light weight and improved strength at the same time.