bluuebunny/crossref_metadata_2025 huggingface dataset:
Response of Drone Electronic Systems to a Standardized Lightning Pulse
Authors: Szczupak Paweł , Kossowski Tomasz
Published: October 2021

This paper presents the results of experimental tests of the impulse response of selected, essential components of a drone. A standardized lightning pulse that is often used during immunity tests of electronic devices in the aviation industry was applied. A single-stroke voltage impulse generator, MIG0618SS, was capable of producing the desired pulses. The input voltage was injected into selected electronic circuits of the drone system and pulses were observed in different parts of the machine. This allowed us to build a model based on the transmittance of the circuits most exposed to lightning overvoltages. The conducted tests were supported by impedance measurements carried out with an LCR-8110G meter. The obtained results made possible the development of a preliminary drone simulation model, allowing us to determine the size of the disturbances arising in individual circuits during nearby lightning. A discussion of the influence of close lightning discharges on expected induced overvoltages in a drone electronics system is also conducted in the paper.
Determination of Relationship between Higher Heating Value and Atomic Ratio of Hydrogen to Carbon in Spent Coffee Grounds by Hydrothermal Carbonization
Authors: Park Jung , Lee Gi , Jeong Cheol , Kim Ho , Kim Choong
Published: October 2021

This study was a preliminary investigation of solid recovered fuel production from spent coffee grounds using the hydrothermal carbonization (HTC) technique. The spent coffee grounds (SCGs) were subjected to HTC at 170 to 250 °C. The biochar was characterized by proximate analysis, ultimate analysis, capillary suction time, time to filter, suspended solids, and particle size distribution. The biochar yields decreased with increasing HTC temperature and time. However, the higher heating value (HHV) of biochar increased with the HTC temperature and time. The H/C slop relative to the O/C atomic rate of spent coffee grounds was 0.10 with low decarboxylation selectivity. Considering the HHV of biochar and dehydration capacity depend on ratio of H/C vs. O/C, the optimum reaction temperature of HTC was 200 °C, and the biochar from SCGs is an attractive biochar.
An Investigation into Current Sand Control Testing Practices for Steam Assisted Gravity Drainage Production Wells
Authors: Kotb Omar , Haftani Mohammad , Nouri Alireza
Published: October 2021

Sand control screens (SCD) have been widely installed in wells producing bitumen from unconsolidated formations. The screens are typically designed using general rules-of-thumb. The sand retention testing (SRT) technique has gained attention from the industry for the custom design and performance assessment of SCD. However, the success of SRT experimentation highly depends on the accuracy of the experimental design and variables. This work examines the impact of the setup design, sample preparation, near-wellbore stress conditions, fluid flow rates, and brine chemistry on the testing results and, accordingly, screen design. The SRT experiments were carried out using the replicated samples from the McMurray Formation at Long Lake Field. The results were compared with the test results on the original reservoir samples presented in the literature. Subsequently, a parametric study was performed by changing one testing parameter at a test, gradually making the conditions more comparable to the actual wellbore conditions. The results indicate that the fluid flow rate is the most influential parameter on sand production, followed by the packing technique, stress magnitude, and brine salinity level. The paper presents a workflow for the sand control testing procedure for designing the SCD in the steam-assisted gravity drainage (SAGD) operations.
Epidemiological Analysis of COVID-19 Cases in Native Amazonian Communities from Peru
Authors: Pajuelo-Reyes Cecilia , Valencia Hugo J. , Montenegro Carla C. , Quezada Eduardo , Gonzales Lizandro , Cruz Norma , Canelo Carlos , Ordinola Carla , Maicelo Quintana Jorge L. , Tejedo Juan R. , Tapia-Limonchi Rafael , Chenet Stella M.
Published: October 2021

Despite early control measures, SARS-CoV-2 reached all regions of Peru during the first wave of the pandemic, including native communities of the Peruvian Amazon. Here, we aimed to describe the epidemiological situation of COVID-19 in the Amazonas region of Peru using an open database of 11,124 COVID-19 cases reported from 19 March to 29 July 2020, including 3278 cases from native communities. A high-incidence area in northern Amazonas (Condorcanqui) reported a cumulative incidence of 63.84/1000 inhabitants with a much lower death rate (0.95%) than the national average. Our results showed at least eight significant factors for mortality, and the Native Amazonian ethnicity as a protective factor. Molecular confirmatory tests are necessary to better explain the high incidence of antibody response reported in these communities.
Role of Enhancers in Development and Diseases
Authors: Maurya Shailendra S.
Published: October 2021

Enhancers are cis-regulatory elements containing short DNA sequences that serve as binding sites for pioneer/regulatory transcription factors, thus orchestrating the regulation of genes critical for lineage determination. The activity of enhancer elements is believed to be determined by transcription factor binding, thus determining the cell state identity during development. Precise spatio-temporal control of the transcriptome during lineage specification requires the coordinated binding of lineage-specific transcription factors to enhancers. Thus, enhancers are the primary determinants of cell identity. Numerous studies have explored the role and mechanism of enhancers during development and disease, and various basic questions related to the functions and mechanisms of enhancers have not yet been fully answered. In this review, we discuss the recently published literature regarding the roles of enhancers, which are critical for various biological processes governing development. Furthermore, we also highlight that altered enhancer landscapes provide an essential context to understand the etiologies and mechanisms behind numerous complex human diseases, providing new avenues for effective enhancer-based therapeutic interventions.
One Omics Approach Does Not Rule Them All: The Metabolome and the Epigenome Join Forces in Haematological Malignancies
Authors: Kalushkova Antonia , Nylund Patrick , Párraga Alba Atienza , Lennartsson Andreas , Jernberg-Wiklund Helena
Published: October 2021

Aberrant DNA methylation, dysregulation of chromatin-modifying enzymes, and microRNAs (miRNAs) play a crucial role in haematological malignancies. These epimutations, with an impact on chromatin accessibility and transcriptional output, are often associated with genomic instability and the emergence of drug resistance, disease progression, and poor survival. In order to exert their functions, epigenetic enzymes utilize cellular metabolites as co-factors and are highly dependent on their availability. By affecting the expression of metabolic enzymes, epigenetic modifiers may aid the generation of metabolite signatures that could be utilized as targets and biomarkers in cancer. This interdependency remains often neglected and poorly represented in studies, despite well-established methods to study the cellular metabolome. This review critically summarizes the current knowledge in the field to provide an integral picture of the interplay between epigenomic alterations and the cellular metabolome in haematological malignancies. Our recent findings defining a distinct metabolic signature upon response to enhancer of zeste homolog 2 (EZH2) inhibition in multiple myeloma (MM) highlight how a shift of preferred metabolic pathways may potentiate novel treatments. The suggested link between the epigenome and the metabolome in haematopoietic tumours holds promise for the use of metabolic signatures as possible biomarkers of response to treatment.
Conifer Establishment and Encroachment on Subalpine Meadows around Mt. Baker, WA, USA
Authors: Hagedorn Ben , Flower Aquila
Published: October 2021

The subalpine ecotone is experiencing significant changes in habitat availability and connectivity as a result of climate change. The conversion of meadow habitats to forests has been observed in many mountainous regions. Rates of conifer encroachment into meadows appears to have increased in the 20th century, but the patterns of conifer establishment seem highly variable over both space and time. To understand how and why these changes vary temporally and spatially in the Pacific Northwest, we collected cross-sections and whorl counts from conifers along four transects in subalpine meadows around Mt. Baker, Washington. We quantified the relationships between temporal patterns of conifer establishment and a suite of climate variables, and between spatial patterns of conifer density and microsite characteristics. Our results show that establishment occurred in pulses throughout the 20th century, with greater establishment on drier sites during periods of greater precipitation, and greater establishment on wetter sites during periods of higher temperatures. We found that April precipitation and September temperature are particularly strongly correlated with establishment rates, suggesting that the best conditions for conifer seedling establishment occur in years with the warmth and soil moisture needed for the growing season to start earlier or last longer. Within individual meadows, conifer seedling establishment was greater on convex surfaces and in areas with a higher percentage of Vaccinium cover. Our findings at Mt. Baker show that periods of conifer establishment occurred somewhat synchronously across multiple mountains in the region, but we also identified distinct spatial and temporal differences linked to local site conditions.
Physiological and Psychological Effects of Nature Experiences in Different Forests on Young People
Authors: Liu Qiaohui , Wang Xiaoping , Liu Jinglan , An Congying , Liu Yuqi , Fan Xiaoli , Hu Yishen
Published: October 2021

Many studies have proved that having nature experiences in forests is conducive to human physiological and psychological health. However, currently there is little research focusing on the effects of forest characteristics and the experiential characteristics of nature experiences on changes in health. In the study, three types of forest (mixed forest; deciduous forest; coniferous forest) and an urban site were used to measure the effects of these environments on participants’ physiological and psychological restoration after nature experience activities (sitting and walking activities). The study participants were 30 young adult students from Beijing Forestry University. Restorative effects were measured by physiological indicators (blood pressure and heart rate) and four psychological questionnaires (Profile of Mood States (POMS); Restorative Outcome Scale (ROS); Subjective Vitality Scale (SVS); Warwick-Edinburgh Mental Well-being Scale (WEMWBS)). Results demonstrated that all types of forest were beneficial to lower blood pressure and heart rate as well as to reduce negative feelings while boosting positive emotions. The mixed forest was more effective in lowering blood pressure and heart rate as well as increasing vitality. The levels of restoration and positive mental health increased significantly, while all subscales of the POMS (with the exception of vigor) decreased greatly in the coniferous forest. Relative to the sitting activity, obvious decreases in blood pressure and negative emotions were observed, while significant increases in restoration, vitality and positive mental health were observed after the walking activity. In conclusion, the impact on subjects’ health restoration varied with different forest characteristics, and the experiential characteristics of exposure may be helpful for creating supportive interventions and lifting the benefits of forest therapy as people interact with the forest.
Chemical and Sensory Characterization of Vidal Icewines Fermented with Different Yeast Strains
Authors: Tang Ke , Sun Yulu , Zhang Xiaoqian , Li Jiming , Xu Yan
Published: October 2021

The aim of this study is to comprehensively investigate the aroma composition and sensory attributes of Vidal icewine fermented with four yeast strains (ST, K1, EC1118, and R2). A total of 485 kinds of volatile components were identified by comprehensive two-dimensional gas chromatography-time of flight mass spectrometry, among which 347 kinds of volatile compounds were the same in four kinds of sample. The heat map was conducted with 156 volatile compounds, which have aroma contributions, and the analysis results identified the characteristics of the aroma composition of icewine fermented with different yeasts. Quantitative descriptive analysis was performed with a trained panel to obtain the sensory profiles. The aroma attributes of honey and nut of the icewine fermented by R2 were much higher than others. Partial least squares discriminant analysis further provided 40 compounds that were mainly responsible for the differences of the aroma characteristics of the icewines fermented by four yeasts. This study provides more data on the current status of Vidal icewines by main commercial yeasts.
Peculiar Response in the Co-Culture Fermentation of Leuconostoc mesenteroides and Lactobacillus plantarum for the Production of ABE Solvents
Authors: Ijoma Grace N. , Adegbenro Gbenga , Rashama Charles , Matambo Tonderayi S.
Published: October 2021

Two bacterial strains (CL11A and CL11D) that are capable of ABE fermentation, identified as Leuconostoc mesenteroides and Weissella cibari, were isolated from the soil surrounding the roots of bean plants. Another strain (ZM 3A), identified as Lactobacillus plantarum, which is capable of purely ethanolic fermentation was isolated from sugarcane. Glucose was used as a standard substrate to investigate the performance of these strains in mono—and co-culture fermentation for ABE production. The performance parameters employed in this study were substrate degradation rates, product and metabolite yields, pH changes and microbial growth rates. Both ABE isolates were capable of producing the three solvents but Leuconostoc mesenteroides had a higher specificity for ethanol than Weissella cibari. The co-culturing of Leuconostoc mesenteroides and Lactobacillus plantarum enhanced ethanol production at the expense of both acetone and butanol, and also influenced the final substrate consumption rate and product yield. The experiments indicated the potential of these niche environments for the isolation of ABE-producing microorganisms. This study contributes to the formulation of ideal microbial co-culture and consortia fermentation, which seeks to maximize the yield and production rates of favored products.
The Effect of Microbial Transglutaminase on the Viscosity and Protein Network of Kefir Made from Cow, Goat, or Donkey Milk
Authors: Darnay Lívia , Tóth Adrienn , Csehi Barbara , Szepessy Anna , Horváth Martin , Pásztor-Huszár Klára , Laczay Péter
Published: October 2021

In this study, we aim to decrease the fermentation time and to produce low-fat set-type kefir with adequate textural properties using microbial transglutaminase without inactivation. In addition, we reveal the effect of microbial transglutaminase, during and after fermentation, on kefir made with cow, goat, or donkey milk, which is a novel approach. Fermentation is followed by continuous pH and viscosity measurements; the final product is characterized by dry matter content, whey separation, protein pattern, and viscosity parameters, as well as gel firmness. The results show that already 0.5 U/g protein dosage of MTGase decreases pH levels independent of milk type, but MTGase does not influence the kinetics of fermentation. Apparent viscosity could be measured from different stages of fermentation depending on milk type (cow milk, 6 h; goat milk, 8 h; and donkey milk, 9 h). The final product characteristics show that the higher the casein ratio of the applied milk, the better the viscosity and gel firmness of the kefir due to the high reaction affinity of MTGase.
Artificial Neural Networks and Gompertz Functions for Modelling and Prediction of Solvents Produced by the S. cerevisiae Safale S04 Yeast
Authors: Moya Almeida Vinicio , Diezma Iglesias Belén , Correa Hernando Eva Cristina
Published: October 2021

The present work aims to develop a mathematical model, based on Gompertz equations and ANNs to predict the concentration of four solvent compounds (isobutanol, ethyl acetate, amyl alcohol and n-propanol) produced by the yeasts S. cerevisiae, Safale S04, using only the fermentation temperature as input data. A beer wort was made, daily samples were taken and analysed by GC-FID. The database was grouped into five datasets of fermentation at different setpoint temperatures (15.0, 16.5, 18.0, 19.0 and 21.0 °C). With these data, the Gompertz models were parameterized, and new virtual datasets were used to train the ANNs. The coefficient of determination (R2) and p-value were used to compare the results. The ANNs, trained with the virtual data generated with the Gompertz functions, were the models with the highest R2 values (0.939 to 0.996), showing that the proposed methodology constitutes a useful tool to improve the quality (flavour and aroma) of beers through temperature control.
Insights on the Advancements of In Silico Metabolic Studies of Succinic Acid Producing Microorganisms: A Review with Emphasis on Actinobacillus succinogenes
Authors: Dessie Wubliker , Wang Zongcheng , Luo Xiaofang , Wang Meifeng , Qin Zuodong
Published: October 2021

Succinic acid (SA) is one of the top candidate value-added chemicals that can be produced from biomass via microbial fermentation. A considerable number of cell factories have been proposed in the past two decades as native as well as non-native SA producers. Actinobacillus succinogenes is among the best and earliest known natural SA producers. However, its industrial application has not yet been realized due to various underlying challenges. Previous studies revealed that the optimization of environmental conditions alone could not entirely resolve these critical problems. On the other hand, microbial in silico metabolic modeling approaches have lately been the center of attention and have been applied for the efficient production of valuable commodities including SA. Then again, literature survey results indicated the absence of up-to-date reviews assessing this issue, specifically concerning SA production. Hence, this review was designed to discuss accomplishments and future perspectives of in silico studies on the metabolic capabilities of SA producers. Herein, research progress on SA and A. succinogenes, pathways involved in SA production, metabolic models of SA-producing microorganisms, and status, limitations and prospects on in silico studies of A. succinogenes were elaborated. All in all, this review is believed to provide insights to understand the current scenario and to develop efficient mathematical models for designing robust SA-producing microbial strains.
Influence of the Initial Sugar Concentration and Supplementation with Yeast Extract on Succinic Acid Fermentation in a Lactose-Based Medium
Authors: Terboven Christiane , Abendroth Christian , Laumer Janin , Herrmann Christiane , Schneider Roland , Ramm Patrice , Venus Joachim , Plöchl Matthias
Published: October 2021

The aim of this study was to investigate the production of succinic acid from lactose concentrate, a by-product of cheese-making, using Actinobacillus succinogenes and Basfia succiniciproducens. Although the ability of these strains to metabolize different sugars is already known, their application in the conversion of lactose bears high potential for optimization. With regard to B. succiniciproducens, this approach is completely novel. In particular, the effect of the medium’s sugar concentration as well as the ability of its supplementation with yeast extract to prevent a lack of essential nutrient proteins and vitamins was examined. Lactose-based media containing sugar concentrations of between 20 and 65 g L−1 and 5 g L−1 of yeast extract were fermented, with both strains showing comparable performances. The best results in terms of succinic acid yield and acid concentration—0.57 g g−1 initial sugar and 23 g L−1—were achieved at an initial sugar concentration of 43 g L−1. The necessity of yeast extract was demonstrated using the sugar-optimized medium without supplementation. As a result, the yield and concentration of succinic acid dropped to 0.34 g g−1 and 13 g L−1 and the sugar consumption decreased from more than 99 to less than 55%. Therefore, the supplementation amount of 5 g L−1 of yeast extract can be regarded as well-balanced.
Nutritional Compositions of Optimally Processed Umqombothi (a South African Indigenous Beer)
Authors: Hlangwani Edwin , Adebiyi Janet Adeyinka , Adebo Oluwafemi Ayodeji
Published: October 2021

Umqombothi (a South African indigenous beer) is an important dietary beverage for many undernourished, low-income consumers in rural, semi-urban and urban areas. Umqombothi was brewed using optimal conditions earlier obtained and compared to the customary beer brew (CB) and mixed raw ingredients (RI). The products were evaluated for proximate compositions, minerals, amino acids, B-group vitamins, and sugar compounds. The optimised beer brew (OPB) was relatively higher in energy (165 kcal), crude protein (8.6%), and ash content (1.0%). The CB had the highest concentration of sodium (299.8 mg/kg), magnesium (1170.5 mg/kg), potassium (2993.8 mg/kg), and phosphorus (2100.7 mg/kg). Glutamic acid was the highest detected amino acid, with concentrations of 1.5 g/100 g, 1.5 g/100 g, and 1.6 g/100 g in the RI, CB, and OPB, respectively. The OPB contained a higher concentration of the two forms of vitamin B3, nicotinamide (0.2 µg/g) and nicotinic acid (0.7 µg/g) in comparison to the CB. The concentration of the antioxidant, mannitol, was 0.4 mg/g, 0.2 mg/g, and 2.0 mg/g in the RI, CB, and OPB respectively. Overall, OPB displayed a desirable nutritional profile compared to the CB.
Bacillus velezensis Identification and Recombinant Expression, Purification, and Characterization of Its Alpha-Amylase
Authors: Zhang Xiaodong , Li Caixia , Chen Xuantong , Chio Chonlong , Shrestha Sarita , Qin Wensheng
Published: October 2021

Amylases account for about 30% of the global market of industrial enzymes, and the current amylases cannot fully meet industrial needs. This study aimed to identify a high α-amylase producing bacterium WangLB, to clone its α-amylase coding gene, and to characterize the α-amylase. Results showed that WangLB belonged to Bacillus velezensis whose α-amylase gene was 1980 bp coding 659 amino acids designated as BvAmylase. BvAmylase was a hydrophilic stable protein with a signal peptide and a theoretical pI of 5.49. The relative molecular weight of BvAmylase was 72.35 kDa, and was verified by SDS-PAGE. Its modeled structure displayed that it was a monomer composed of three domains. Its optimum temperature and pH were 70 °C and pH 6.0, respectively. It also showed high activity in a wide range of temperatures (40–75 °C) and a relatively narrow pH (5.0–7.0). It was a Ca2+-independent enzyme, whose α-amylase activity was increased by Co2+, Tween 20, and Triton X-100, and severely decreased by SDS. The Km and the Vmax of BvAmylase were 3.43 ± 0.53 and 434.19 ± 28.57 U/mg. In conclusion, the α-amylase producing bacterium WangLB was identified, and one of its α-amylases was characterized, which will be a candidate enzyme for industrial applications.
Novel Processing Technology of Dairy Products
Authors: Moschopoulou Ekaterini
Published: October 2021

Milk has been processed into dairy products using traditional methods for hundreds of years [...]
Odor Emissions from Raw Meat of Freshly Slaughtered Cattle during Inspection
Authors: Conte Francesca , Cincotta Fabrizio , Condurso Concetta , Verzera Antonella , Panebianco Antonio
Published: October 2021

Raw meat of Freshly Slaughtered Cattle (FSC) is characterized by a very weak odor defined as slightly sweet, which could interfere in off-odor assessment during post-mortem inspection by an official veterinarian. Despite this, no information is reported in the literature on the volatiles which are emitted by FSC meat. Thus, this research aimed to study the volatile profile of raw cattle meat at different times within 24 h of slaughtering. Volatiles were analyzed and quantified using HS-SPME-GC-MS. γ-Butyrolactone, acetoin, and to a lesser extent, acid acetic were found to be the odor-active compounds of raw meat from freshly slaughtered cattle. Quantitative differences were observed up to 24 h; since the lowest levels of the odor-active compounds were reached between two and three hours from slaughtering, this period could be the most suitable for the post-mortem inspection process.
On the Autoregressive Time Series Model Using Real and Complex Analysis
Authors: Ullrich Torsten
Published: October 2021

The autoregressive model is a tool used in time series analysis to describe and model time series data. Its main structure is a linear equation using the previous values to compute the next time step; i.e., the short time relationship is the core component of the autoregressive model. Therefore, short-term effects can be modeled in an easy way, but the global structure of the model is not obvious. However, this global structure is a crucial aid in the model selection process in data analysis. If the global properties are not reflected in the data, a corresponding model is not compatible. This helpful knowledge avoids unsuccessful modeling attempts. This article analyzes the global structure of the autoregressive model through the derivation of a closed form. In detail, the closed form of an autoregressive model consists of the basis functions of a fundamental system of an ordinary differential equation with constant coefficients; i.e., it consists of a combination of polynomial factors with sinusoidal, cosinusoidal, and exponential functions. This new insight supports the model selection process.
New Estimations of Hermite–Hadamard Type Integral Inequalities for Special Functions
Authors: Ahmad Hijaz , Tariq Muhammad , Sahoo Soubhagya Kumar , Baili Jamel , Cesarano Clemente
Published: October 2021

In this paper, we propose some generalized integral inequalities of the Raina type depicting the Mittag–Leffler function. We introduce and explore the idea of generalized s-type convex function of Raina type. Based on this, we discuss its algebraic properties and establish the novel version of Hermite–Hadamard inequality. Furthermore, to improve our results, we explore two new equalities, and employing these we present some refinements of the Hermite–Hadamard-type inequality. A few remarkable cases are discussed, which can be seen as valuable applications. Applications of some of our presented results to special means are given as well. An endeavor is made to introduce an almost thorough rundown of references concerning the Mittag–Leffler functions and the Raina functions to make the readers acquainted with the current pattern of emerging research in various fields including Mittag–Leffler and Raina type functions. Results established in this paper can be viewed as a significant improvement of previously known results.
Reduction Formulas for Generalized Hypergeometric Series Associated with New Sequences and Applications
Authors: Choi Junesang , Qureshi Mohd Idris , Bhat Aarif Hussain , Majid Javid
Published: October 2021

In this paper, by introducing two sequences of new numbers and their derivatives, which are closely related to the Stirling numbers of the first kind, and choosing to employ six known generalized Kummer’s summation formulas for 2F1(−1) and 2F1(1/2), we establish six classes of generalized summation formulas for p+2Fp+1 with arguments −1 and 1/2 for any positive integer p. Next, by differentiating both sides of six chosen formulas presented here with respect to a specific parameter, among numerous ones, we demonstrate six identities in connection with finite sums of 4F3(−1) and 4F3(1/2). Further, we choose to give simple particular identities of some formulas presented here. We conclude this paper by highlighting a potential use of the newly presented numbers and posing some problems.
The Solutions of Some Riemann–Liouville Fractional Integral Equations
Authors: Kaewnimit Karuna , Wannalookkhee Fongchan , Nonlaopon Kamsing , Orankitjaroen Somsak
Published: October 2021

In this paper, we propose the solutions of nonhomogeneous fractional integral equations of the form I0+3σy(t)+a·I0+2σy(t)+b·I0+σy(t)+c·y(t)=f(t), where I0+σ is the Riemann–Liouville fractional integral of order σ=1/3,1,f(t)=tn,tnet,n∈N∪{0},t∈R+, and a,b,c are constants, by using the Laplace transform technique. We obtain solutions in the form of Mellin–Ross function and of exponential function. To illustrate our findings, some examples are exhibited.
Unravelling Theory: Strategic (Non-) Disclosure of Online Ratings
Authors: Butler David , Read Daniel
Published: October 2021

This paper investigates disclosure by testing if the game theoretic predictions of unravelling theory are borne out in a heretofore unstudied market. We analyse TripAdvisor disclosures from hoteliers across 22 locations (N = 4357). Contrary to theoretical predictions, we find that disclosure decreases linearly with TripAdvisor ratings. We find the same pattern of disclosure occurs when consumers know the information provider has information to disclose, and when they do not. We also find evidence suggesting the most elite hotels may disclose less. We provide practical as well as theoretical implications.
Dynamic Model of Collaboration in Multi-Agent System Based on Evolutionary Game Theory
Authors: Gou Zhuozhuo , Deng Yansong
Published: October 2021

Multi-agent collaboration is greatly important in order to reduce the frequency of errors in message communication and enhance the consistency of exchanging information. This study explores the process of evolutionary decision and stable strategies among multi-agent systems, including followers, leaders, and loners, involved in collaboration based on evolutionary game theory (EGT). The main elements that affected the strategies are discussed, and a 3D evolution model is established. The evolutionary stability strategy (ESS) and stable conditions were analyzed subsequently. Numerical simulation results were obtained through MATLAB simulation, and they manifested that leaders play an important role in exchanging information with other agents, accepting agents’ state information, and sending messages to agents. Then, with the positivity of receiving and feeding back messages for followers, implementing message communication is profitable for the system, and the high positivity can accelerate the exchange of information. At the behavior level, reducing costs can strengthen the punishment of impeding the exchange of information and improve the positivity of collaboration to facilitate the evolutionary convergence toward the ideal state. Finally, the EGT results revealed that the possibility of collaboration between loners and others is improved, and the rewards are increased, thereby promoting the implementation of message communication that encourages leaders to send all messages, improve the feedback positivity of followers, and reduce the hindering degree of loners.
Singularities in Static Spherically Symmetric Configurations of General Relativity with Strongly Nonlinear Scalar Fields
Authors: Stashko Oleksandr , Zhdanov Valery I.
Published: October 2021

There are a number of publications on relativistic objects dealing either with black holes or naked singularities in the center. Here we show that there exist static spherically symmetric solutions of Einstein equations with a strongly nonlinear scalar field, which allow the appearance of singularities of a new type (“spherical singularities”) outside the center of curvature coordinates. As the example, we consider a scalar field potential ∼sinh(ϕ2n),n>2, which grows rapidly for large field values. The space-time is assumed to be asymptotically flat. We fulfill a numerical investigation of solutions with different n for different parameters, which define asymptotic properties at spatial infinity. Depending on the configuration parameters, we show that the distribution of the stable circular orbits of test bodies around the configuration is either similar to that in the case of the Schwarzschild solution (thus mimicking an ordinary black hole), or it contains additional rings of unstable orbits.
Water Uptake as a Crucial Factor on the Properties of Cryogels of Gelatine Cross-Linked by Dextran Dialdehyde
Authors: Volkova Natalia , Berillo Dmitriy
Published: October 2021

We investigated the water sorption properties of macroporous cryogels of gelatine (Gel) and dextran dialdehyde (DDA) prepared via cryogelation at 260 K and following the freeze drying processes. Water vapour sorption isotherms for aerogels were studied at 293 K by two independent methods: static-gravimetric and dynamic vapour sorption (DVS) over a water activity range of 0.11–1.0. Experimental data were fitted by use of the Brunauer–Emmett–Teller (BET) and Guggenheim–Anderson–de Boer (GAB) models. The BET model (for a water activity range of 0.1 ≤ p/po ≤ 0.5) was used to calculate the sorption parameters of the studied cryogels (the monolayer capacity, surface area and energy of interaction). In comparison with BET, the GAB model can be applied for the whole range of water activities (0.1 ≤ p/po ≤ 0.95). This model gave an almost perfect correlation between the experimental and calculated sorption isotherms using nonlinear least squares fitting (NLSF). Confocal Laser Scanning Microscopy (CLSM) was used to confirm the structural differences between various DDA:Gel cryogel compositions. Thermogravimetric analysis and DSC data for aerogels DDA:Gel provided information regarding the bonded water loss, relative remaining water content of the material and the temperature of decomposition. Estimation of the amount of bound water in the cryogels after the freeze drying process as well as after the cycle of treatment of cryogels with high humidity and drying was performed using DSC. The results of the DSC determinations showed that cryogels with higher gelatin content had higher levels of bonded water.
Shellac Gum/Carrageenan Alginate-Based Core–Shell Systems Containing Peppermint Essential Oil Formulated by Mixture Design Approach
Authors: Foglio Bonda Andrea , Candiani Alessandro , Pertile Martina , Giovannelli Lorella , Segale Lorena
Published: October 2021

Peppermint essential oil is encapsulated by inverse ionotropic gelation in core–shell systems, composed of alginate (ALG) alone or alginate with shellac gum (SHL) and/or carrageenan (CRG). A mixture design approach is used to evaluate the correlation between the formulation composition and some properties of the final products. Immediately after the preparation, capsules appear rounded with a smooth and homogeneous surface, having a similar particle size ranging from 3.8 mm to 4.5 mm. The drying process, carried out at 40 °C in an oven for 3 h, reduces capsules’ diameters by at least 50% and has a negative impact on the shape of the systems because they lose their regular shape and their external membrane partially collapses. The peppermint essential oil content of dried capsules is between 14.84% and 33.75%. The swelling behaviour of the systems is affected by the composition of their outer shell. When the external membrane is composed of alginate and shellac gum, the capsule ability to swell is lower than that of the systems containing alginate alone. The swelling ratio reaches 31% for alginate capsules but does not exceed 21% if shellac is present. Differently, when the second polymer of the shell is carrageenan, the swelling ability increases as a function of polymer concentration and the swelling ratio reaches 360%. In the case of systems whose outer membrane is a polymeric ternary mixture, the swelling capacity increases or decreases according to the concentrations of the individual polymers. The obtained results suggest that carrageenan could be a useful excipient to increase the swelling behaviour of the systems, while shellac gum makes the system shell more hydrophobic. The use of a mixture design (i.e., the use of ternary diagrams and related calculations), in which each single component is chosen to provide specific properties to the final mixture, could be the right approach to develop improved formulations with a tailored essential oil release profile.
In Vitro Evaluation of a Composite Gelatin–Hyaluronic Acid–Alginate Porous Scaffold with Different Pore Distributions for Cartilage Regeneration
Authors: Haung Ssu-Meng , Lin Yu-Ting , Liu Shih-Ming , Chen Jian-Chih , Chen Wen-Cheng
Published: October 2021

Although considerable achievements have been made in the field of regenerative medicine, since self-repair is not an advanced ability of articular cartilage, the regeneration of osteochondral defects is still a challenging problem in musculoskeletal diseases. Cartilage regeneration aims to design a scaffold with appropriate pore structure and biological and mechanical properties for the growth of chondrocytes. In this study, porous scaffolds made of gelatin, hyaluronic acid, alginate, and sucrose in different proportions of 2 g (SL2) and 4 g (SL4) were used as porogens in a leaching process. Sucrose with particle size ranges of 88–177 μm (Hμ) and 44–74 μm (SHμ) was added to the colloid, and the individually cross-linked hydrogel scaffolds with controllable pore size for chondrocyte culture were named Hμ-SL2, Hμ-SL4, SHμ-SL2 and SHμ-SL4. The perforation, porosity, mechanical strength, biocompatibility, and proliferation characteristics of the hydrogel scaffold and its influence on chondrocyte differentiation are discussed. Results show that the addition of porogen increases the porosity of the hydrogel scaffold. Conversely, when porogens with the same particle size are added, the pore size decreases as the amount of porogen increases. The perforation effect of the hydrogel scaffolds formed by the porogen is better at 88–177 μm compared with that at 44–74 μm. Cytotoxicity analysis showed that all the prepared hydrogel scaffolds were non-cytotoxic, indicating that no cross-linking agent residues that could cause cytotoxicity were found. In the proliferation and differentiation of the chondrocytes, the SHμ-SL4 hydrogel scaffold with the highest porosity and strength did not achieve the best performance. However, due to the compromise between perforation pores, pore sizes, and strength, as well as considering cell proliferation and differentiation, Hμ-SL4 scaffold provided a more suitable environment for the chondrocytes than other groups; therefore, it can provide the best chondrocyte growth environment for this study. The development of hydrogels with customized pore properties for defective cartilage is expected to meet the requirements of the ultimate clinical application.
Revisiting Distant Relations
Authors: Freeman Victoria
Published: October 2021

In 2000, I published Distant Relations: How My Ancestors Colonized North America, a non-fiction exploration of my own family’s involvement in North American colonialism from the 1600s to the present. This personal essay reflects on the context, genesis, process, and consequences of writing this book during a decade of intense ferment in Indigenous–settler relations in Canada amid the revelations of horrific abuse at residential schools and the discovery that my highly respected grandfather had been involved with one. Considering the book from the perspective of 2021, I consider the strengths and limitations of this kind of critical family history and the degree to which public discourses and academic discussion of Canada’s history and settler complicity in colonialism have changed since the book was published. Arguing that critical reflection on family history is still an essential part of unlearning colonial attitudes and recognizing the systemic and structural ways that colonial disparities and processes are embedded in settler societies, I share a critical family history assignment that has been an essential and transformative pedagogical element in my university teaching for both Indigenous and non-Indigenous students.
Multiplex Protein Biomarker Profiling in Patients with Familial Hypercholesterolemia
Authors: Dlouha Dana , Blaha Milan , Rohlova Eva , Hubacek Jaroslav A. , Lanska Vera , Visek Jakub , Blaha Vladimir
Published: October 2021

Familial hypercholesterolemia (FH), is an autosomal dominant disorder caused by mutations in the LDLR, APOB, PCSK9, and APOE genes and is characterized by high plasma levels of total and low-density lipoprotein (LDL) cholesterol. Our study aimed to analyze the influences of two different therapies on a wide spectrum of plasma protein biomarkers of cardiovascular diseases. Plasma from FH patients under hypolipidemic therapy (N = 18; men = 8, age 55.4 ± 13.1 years) and patients under combined long-term LDL apheresis/hypolipidemic therapy (N = 14; men = 7; age 58.0 ± 13.6 years) were analyzed in our study. We measured a profile of 184 cardiovascular disease (CVD) associated proteins using a proximity extension assay (PEA). Hypolipidemic therapy significantly (all p < 0.01) influenced 10 plasma proteins (TM, DKK1, CCL3, CD4, PDGF subunit B, AGRP, IL18, THPO, and LOX1 decreased; ST2 increased). Under combined apheresis/hypolipidemic treatment, 18 plasma proteins (LDLR, PCSK9, MMP-3, GDF2, CTRC, SORT1, VEGFD, IL27, CCL24, and KIM1 decreased; OPN, COL1A1, KLK6, IL4RA, PLC, TNFR1, GLO1, and PTX3 increased) were significantly affected (all p < 0.006). Hypolipidemic treatment mainly affected biomarkers involved in vascular endothelial maintenance. Combined therapy influenced proteins that participate in cholesterol metabolism and inflammation.
Threshold Effects of Relative Sea-Level Change in Intertidal Ecosystems: Empirical Evidence from Earthquake-Induced Uplift on a Rocky Coast
Authors: Orchard Shane , Fischman Hallie S. , Gerrity Shawn , Alestra Tommaso , Dunmore Robyn , Schiel David R.
Published: October 2021

Widespread mortality of intertidal biota was observed following the 7.8 Mw Kaikōura earthquake in November 2016. To understand drivers of change and recovery in nearshore ecosystems, we quantified the variation in relative sea-level changes caused by tectonic uplift and evaluated their relationships with ecological impacts with a view to establishing the minimum threshold and overall extent of the major effects on rocky shores. Vertical displacement of contiguous 50 m shoreline sections was assessed using comparable LiDAR data to address initial and potential ongoing change across a 100 km study area. Co-seismic uplift accounted for the majority of relative sea-level change at most locations. Only small changes were detected beyond the initial earthquake event, but they included the weathering of reef platforms and accumulation of mobile gravels that continue to shape the coast. Intertidal vegetation losses were evident in equivalent intertidal zones at all uplifted sites despite considerable variation in the vertical displacement they experienced. Nine of ten uplifted sites suffered severe (>80%) loss in habitat-forming algae and included the lowest uplift values (0.6 m). These results show a functional threshold of c.1/4 of the tidal range above which major impacts were sustained. Evidently, compensatory recovery has not occurred—but more notably, previously subtidal algae that were uplifted into the low intertidal zone where they ought to persist (but did not) suggests additional post-disturbance adversities that have contributed to the overall effect. Continuing research will investigate differences in recovery trajectories across the affected area to identify factors and processes that will lead to the regeneration of ecosystems and resources.
Dental Students’ Oral Health-Related Quality of Life and Temporomandibular Dysfunction-Self-Rating versus Clinical Assessment
Authors: Schnabl Dagmar , Sandbichler Philipp , Neumaier Maximilian , Girstmair Johannes , Barbieri Fabian , Kapferer-Seebacher Ines , Steiner René , Laimer Johannes , Grunert Ingrid
Published: October 2021

The aim of this study was to compare dental students’ self-perception of oral health with the results of a clinical examination of the masticatory system. Seventy-four dental students (38 (51.4%) females and 36 (48.6%) males) completed the Oral Health Impact Profile questionnaire (OHIP-G-14) and underwent a clinical examination according to the Graz Dysfunction Index (GDI). Data were analyzed with descriptive and comparative statistics. Median OHIP-G-14 scores were 3 (IQR 0–6) in the total collective, 4 (1–11) in females, and 2 (0–4) in males (p = 0.072). A score of 0 was found in 29.7% of the sample. The results of the GDI were 50% “normal function”, 43.2% “adaptation”, 5.4% “compensation”, and 1.4% “dysfunction”. The comparison of OHIP-G-14 scores and DGI groups showed a significant difference (p = 0.031). Based on the questionnaire, less than one third of the sample indicated maximum oral health-related quality of life. In contrast, the GDI revealed “normal function” or “adaptation” in 93.2%. Dental students underappreciated their oral health condition. Health assessments should not be solely questionnaire-based, especially in health professionals (-to-be). To establish a valid diagnosis of the state of health, self-assessment must be complemented by an objective clinical examination, e.g., GDI.
Smartphone Addiction and Depression among Low-Income Boys since COVID-19: The Moderating Effect of Being an Only Child
Authors: Lee Jaewon , Lim Hyejung , Allen Jennifer , Choi Gyuhyun , Jung Jiyu
Published: October 2021

Even though boys’ depression has become important, and their smartphone use has increased since COVID-19, little is known about low-income middle and high school boys’ depression in the context of whether they have siblings. Thus, this study investigates the relationship between smartphone addiction and depression as well as the moderating effect of being an only child on the relationship. Participants were limited to middle and high school students whose families were regarded as having a low-income. A total of 129 low-income boys were selected for the final sample. The PROCESS macro 3.4 for Statistical Product and Service Solutions was used to identify the moderating effect. Smartphone addiction was positively related to depression among low-income male students. Being an only child significantly moderated the relationship between smartphone addiction and depression. This study contributes to understanding the importance of examining mental health problems among middle school boys since COVID-19, particularly among low-income boys. It is necessary to provide tailored mental health services for middle school boys in low-income families. Alternative activities and social programs should be provided for adolescent boys who are only children to safely socialize with friends and peers without a smartphone.