bluuebunny/crossref_metadata_2025 huggingface dataset:
Differentiation Trajectory of Limbal Stem and Progenitor Cells under Normal Homeostasis and upon Corneal Wounding
Authors: Song Zhenwei , Chen Brian , Tsai Chi-Hao , Wu Di , Liu Emily , Hawkins Isha Sharday , Phan Andrew , Auman James Todd , Tao Yazhong , Mei Hua
Published: June 2022

Limbal stem cells (LSCs) reside discretely at limbus surrounded by niche cells and progenitor cells. The aim of this study is to identify the heterogeneous cell populations at limbus under normal homeostasis and upon wounding using single-cell RNA sequencing in a mouse model. Two putative LSC types were identified which showed a differentiation trajectory into limbal progenitor cell (LPC) types under normal homeostasis and during wound healing. They were designated as “putative active LSCs” and “putative quiescent LSCs”, respectively, because the former type actively divided upon wounding while the later type stayed at a quiescent status upon wounding. The “putative quiescent LSCs” might contribute to a barrier function due to their characteristic markers regulating vascular and epithelial barrier and growth. Different types of LPCs at different proliferative statuses were identified in unwounded and wounded corneas with distinctive markers. Four maturation markers (Aldh3, Slurp1, Tkt, and Krt12) were screened out for corneal epithelium, which showed an increased expression along the differentiation trajectory during corneal epithelial maturation. In conclusion, our study identified two different types of putative LSCs and several types of putative LPCs under normal homeostasis and upon wounding, which will facilitate the understanding of corneal epithelial regeneration and wound healing.
Standardization of Cell Culture Conditions and Routine Genomic Screening under a Quality Management System Leads to Reduced Genomic Instability in hPSCs
Authors: Molina-Ruiz Francisco J. , Introna Clelia , Bombau Georgina , Galofre Mireia , Canals Josep M.
Published: June 2022

Human pluripotent stem cells (hPSCs) have generated unprecedented interest in the scientific community, given their potential applications in regenerative medicine, disease modeling, toxicology and drug screening. However, hPSCs are prone to acquire genomic alterations in vitro, mainly due to suboptimal culture conditions and inappropriate routines to monitor genome integrity. This poses a challenge to both the safety of clinical applications and the reliability of basic and translational hPSC research. In this study, we aim to investigate if the implementation of a Quality Management System (QMS) such as ISO9001:2015 to ensure reproducible and standardized cell culture conditions and genomic screening strategies can decrease the prevalence of genomic alterations affecting hPSCs used for research applications. To this aim, we performed a retrospective analysis of G-banding karyotype and Comparative Genomic Hybridization array (aCGH) data generated by our group over a 5-year span of different hESC and hiPSC cultures. This work demonstrates that application of a QMS to standardize cell culture conditions and genomic monitoring routines leads to a striking improvement of genomic stability in hPSCs cultured in vitro, as evidenced by a reduced probability of potentially pathogenic chromosomal aberrations and subchromosomal genomic alterations. These results support the need to implement QMS in academic laboratories performing hPSC research.
A Therapeutic Whole-Tumor-Cell Vaccine Covalently Conjugated with a TLR7 Agonist
Authors: Chi Huju , Hao Yue , Wang Xia , Tang Li , Deng Yongqiang , Chen Xianxiong , Gao Feng , Sha Ou , Jin Guangyi
Published: June 2022

A single-protein or -peptide vaccine is not sufficient to arouse immune responses in cancer therapy. A whole-tumor-cell vaccine with complete cancer cell antigens and all conformations elicits robust immune responses and is a promising method for the treatment of advanced malignant tumors. In this study, we used 5-azacitidine to stimulate B16-F10 melanoma cells to express toll-like receptor (TLR) 3 on the cell surface and then chemically linked SZU-106, a small-molecule TLR7 agonist, to the cell surface with a pegylated linker to produce a novel whole-tumor-cell vaccine, abbreviated as Aza-BFcell-106. The vaccine stimulated mouse splenic lymphocytes and bone marrow-derived dendritic cells to secrete cytokines, promoted the maturation of dendritic cells and enhanced the capability of dendritic cells to present antigens. In a mouse model of melanoma, the vaccine effectively inhibited tumor growth, decreased tumor volume and prolonged survival. Further combination of the vaccine with a chemokine inhibitor, reparixin, significantly increased the infiltration of CD4+ and CD8+ T cells into the tumor environment, while the antitumor effect was significantly enhanced. The whole-tumor-cell vaccine Aza-BFcell-106 induced immune-activating responses in both in vitro and in vivo experiments, indicating that this vaccine has great potential to treat advanced malignant tumors.
Different Sourced Extracellular Vesicles and Their Potential Applications in Clinical Treatments
Authors: Bahmani Leila , Ullah Mujib
Published: June 2022

Extracellular vesicles (EVs) include a heterogeneous group of natural cell-derived nanostructures that are increasingly regarded as promising biotherapeutic agents and drug delivery vehicles in human medicine. Desirable intrinsic properties of EVs including the ability to bypass natural membranous barriers and to deliver their unique biomolecular cargo to specific cell populations position them as fiercely competitive alternatives for currently available cell therapies and artificial drug delivery platforms. EVs with distinct characteristics can be released from various cell types into the extracellular environment as a means of transmitting bioactive components and altering the status of the target cell. Despite the existence of a large number of preclinical studies confirming the therapeutic efficacy of different originated EVs for treating several pathological conditions, in this review, we first provide a brief overview of EV biophysical properties with an emphasis on their intrinsic therapeutic benefits over cell-based therapies and synthetic delivery systems. Next, we describe in detail different EVs derived from distinct cell sources, compare their advantages and disadvantages, and recapitulate their therapeutic effects on various human disorders to highlight the progress made in harnessing EVs for clinical applications. Finally, knowledge gaps and concrete hurdles that currently hinder the clinical translation of EV therapies are debated with a futuristic perspective.
Lung Ultrasound Patterns in Multisystem Inflammatory Syndrome in Children (MIS-C)-Characteristics and Prognostic Value
Authors: Camporesi Anna , Gemma Marco , Buonsenso Danilo , Ferrario Stefania , Mandelli Anna , Pessina Matteo , Diotto Veronica , Rota Elena , Raso Irene , Fiori Laura , Campari Alessandro , Izzo Francesca
Published: June 2022

Objective and design: Following COVID-19 infection, children can develop an hyperinflammatory state termed Multisystem Inflammatory Syndrome in Children (MIS-C). Lung Ultrasound (LUS) features of COVID-19 in children have been described, but data describing the LUS findings of MIS-C are limited. The aim of this retrospective observational study conducted between 1 March and 31 December 2020, at a tertiary pediatric hospital in Milano, is to describe LUS patterns in patients with MIS-C and to verify correlation with illness severity. The secondary objective is to evaluate concordance of LUS with Chest X-ray (CXR). Methodology: Clinical and laboratory data were collected for all patients (age 0–18 years) admitted with MIS-C, as well as LUS and CXR patterns at admission. PICU admission, needed for respiratory support and inotrope administration, hospital, and PICU length of stay, were considered as outcomes and evaluated in the different LUS patterns. An agreement between LUS and CXR evaluation was assessed with Cohen’ k. Results: 24 children, who had a LUS examination upon admission, were enrolled. LUS pattern of subpleural consolidations < or > 1 cm with or without pleural effusion were associated with worse Left Ventricular Ejection Fraction at admission and need for inotropes. Subpleural consolidations < 1 cm were also associated with PICU length of stay. Agreement of CXR with LUS for consolidations and effusion was slight. Conclusion: LUS pattern of subpleural consolidations and consolidations with or without pleural effusion are predictors of disease severity; under this aspect, LUS can be used at admission to stratify risk of severe disease.
Oxidation of Silicon Carbide Composites for Nuclear Applications at Very High Temperatures in Steam
Authors: Steinbrueck Martin , Grosse Mirco , Stegmaier Ulrike , Braun James , Lorrette Christophe
Published: June 2022

Single-rod oxidation and quench experiments at very high temperatures in steam atmosphere were conducted with advanced, nuclear grade SiCf/SiC CMC cladding tube segments. A transient experiment was performed until severe local degradation of the sample at maximum temperature of approximately 1845 °C. The degradation was caused by complete consumption of the external CVD-SiC sealcoat, resulting in steam access to the fiber–matrix composite with less corrosion resistance. Approaching these very high temperatures was accompanied by accelerated gas release mainly of H2 and CO2, the formation of surface bubbles and white smoke. Three one-hour isothermal tests at 1700 °C in steam with final water flooding and one three-hour experiment with fast cool-down in Ar atmosphere were run under nominally identical conditions. All isothermally tested samples survived the tests without any macroscopic degradation. The mechanical performance of these quenched clad segments was not significantly affected, while maintaining a high capability to tolerate damages. Despite these harsh exposure conditions, load transfer between SiC fibers and matrix remained efficient, allowing the composites to accommodate deformation.
Heat-Mediated Transformation of PMMA-SiO2 Core-Shell Particles into Hollow SiO2 Particles
Authors: Sukhinina Nadezhda S. , Masalov Vladimir M. , Fursova Tatiana N. , Khodos Igor I. , Zverkova Irina I. , Zhokhov Andrey A. , Emelchenko Gennadi A.
Published: June 2022

Changes in the morphology and structure of the core-shell particles of polymethyl methacrylate-silicon dioxide and hollow SiO2 particles during their heat treatment were studied by electron microscopy, infrared spectroscopy, and X-ray diffraction. The polymeric core of the PMMA-SiO2 hybrid particle was found to undergo an unusual transformation when exposed to the electron microscope beam: its shrinkage occurs through the formation of a spherical cavity. It was shown that the process of silica-shell formation occurs in the temperature range of 200–600 °C and is accompanied by the loss of vinyl- and OH-groups. It was determined by the method of X-ray diffraction, that in the place of the interaction of PMMA and the shell, the degree of ordering of the polymer is higher than that in the volume of the polymer core. It was shown that the frequency of the TO3-vibrational mode (asymmetric stretching vibrations of the Si–O–Si bonds) increases with an increase in the annealing temperature, which is associated with the densification of the silicon dioxide shell.
The CRISPR/Cas Machinery Evolution and Gene Flow in the Hot Spring Cyanobacterium Thermostichus
Authors: Jahodářová Eva , Poulíčková Aloisie , Dvořák Petr
Published: June 2022

Drivers of the speciation in bacteria, including geographical isolation and horizontal gene transfer, are still poorly understood. Here, we characterized a new lineage within an anciently diverged thermophilic cyanobacteria. We sequenced the whole genome of a strain Thermostichus vulcanus isolated from the Rupite spring (Bulgaria), which is closely related to Theromstichus strains JA-2-3Aa and JA-2-3B′a(2-13). We performed phylogenetic inference, horizontal gene transfer estimation, and CRISPR/Cas system characterization. We found that the Rupite strain is a distinct species from strains JA-2-3Aa, and JA-2-3B′a(2-13). Furthermore, the horizontal gene transfer seemed to be more frequent among the geographically distant species than between the two species within the same hot spring. The CRISPR/Cas system had variable complexity among the species of Thermostichus in terms of both the number of spacers and genes. The Rupite strain had the highest, and JA-2-3Aa the lowest number of spacers among the analyzed strains, and the CRISPR spacers were only rarely shared among the strains. We conclude that the CRISPR/Cas system size varied among the lineages as well as the gene flow.
Diversity and Big Tree Patterns in the Brazilian Amazon
Authors: de Lima Robson Borges , Görgens Eric Bastos , Batista Anderson Pedro Bernardina , da Silva Diego Armando Silva , de Oliveira Cinthia Pereira , de Sousa Carla Samara Campelo
Published: June 2022

The increasing availability of field data presents an opportunity to understand the fundamental ecological relationships and functions of large trees in tropical forests at regional and global scales. However, it is not always clear what the relationships or patterns of diversity and structure are among sites in different biogeographic regions. We evaluated the relationship of the biomass and diameter of the largest trees with a diversity of species and compared, between the sites, the attributes of structure, diversity, and the influence of the 50 hyperdominant species in each site, aiming at the potential formation of groups by sites with characteristics and patterns of similar diversity within biogeographic regions. The average wood density together with the diversity of genera and families are the most important attributes to discriminate biogeographic regions when considering all forest information. Large trees play a fundamental role in forest ecology and seem to express regional environmental characteristics. The upper canopy of tropical forests remains one of the least studied environments in all terrestrial biomes, and is often referred to as “the last biotic frontier” or a “black box,” and large trees are also part of this mysterious frontier.
Why Is There Medical Inertia and Nihilism to Celiac Disease? Comment on Pivetta et al. In Elderly Anemic Patients without Endoscopic Signs of Bleeding Are Duodenal Biopsies Always Necessary to Rule out Celiac Disease? Diagnostics 2022, 12, 678
Authors: Greenaway Emily A. , Raju Suneil A. , Sanders David S.
Published: June 2022

We read, with interest, the paper entitled “In Elderly Anemic Patients without Endoscopic Signs of Bleeding Are Duodenal Biopsies Always Necessary to Rule Out Celiac Disease [...]
Association of Prognostic Nutritional Index with Severity and Mortality of Hospitalized Patients with COVID-19: A Systematic Review and Meta-Analysis
Authors: Hung Kuo-Chuan , Ko Ching-Chung , Wang Li-Kai , Liu Ping-Hsin , Chen I-Wen , Huang Yen-Ta , Sun Cheuk-Kwan
Published: June 2022

The associations of prognostic nutritional index (PNI) with disease severity and mortality in patients with coronavirus disease 2019 (COVID-19) remain unclear. Electronic databases, including MEDLINE, EMBASE, Google scholar, and Cochrane Library, were searched from inception to 10 May 2022. The associations of PNI with risk of mortality (primary outcome) and disease severity (secondary outcome) were investigated. Merged results from meta-analysis of 13 retrospective studies (4204 patients) published between 2020 and 2022 revealed a lower PNI among patients in the mortality group [mean difference (MD): −8.65, p < 0.001] or severity group (MD: −5.19, p < 0.001) compared to those in the non-mortality or non-severity groups. A per-point increase in PNI was associated with a reduced risk of mortality [odds ratio (OR) = 0.84, 95% CI: 0.79 to 0.9, p < 0.001, I2 = 67.3%, seven studies] and disease severity (OR = 0.84, 95% CI: 0.77 to 0.92, p < 0.001, I2 = 83%, five studies). The pooled diagnostic analysis of mortality yielded a sensitivity of 0.76, specificity of 0.71, and area under curve (AUC) of 0.79. Regarding the prediction of disease severity, the sensitivity, specificity, and AUC were 0.8, 0.61, and 0.65, respectively. In conclusion, this study demonstrated a negative association between PNI and prognosis of COVID-19. Further large-scale trials are warranted to support our findings.
How Far Can Nature-Based Solutions Increase Water Supply Resilience to Climate Change in One of the Most Important Brazilian Watersheds?
Authors: de Freitas Letícia , de Moraes Jener , da Costa Adriana , Martins Letícia , Silva Bruno , Avanzi Junior , Uezu Alexandre
Published: June 2022

Water resources are paramount for the maintenance of the Earth’s system equilibrium; however, they face various threats and need increased conservation and better management. To restore water resources, nature-based solutions can be applied. Nevertheless, it is unclear which solution promotes greater water supply resilience: restoring riparian vegetation, improving management practices in key areas for water recharge, or both? In addition, how significant are these results in the face of climate change effects? To answer this, we used the SWAT (Soil and Water Assessment Tool) model to simulate and compare four different land use scenarios under three climate conditions (i.e., observed climate and two of the IPCC’s future climate projections). Focusing on key areas contributed more to increasing water supply resilience than forest restoration. Applying both solutions, however, yielded the greatest increases in resilience and groundwater recharge and the greatest decreases in surface runoff and sediment loads. None of the solutions caused a significant difference in streamflow and water yield. Furthermore, according to both of the IPCC climate projections evaluated, by the end of this century, the average annual streamflow will be lower than the historical mean for the region. Climate adaptation strategies alone will be insufficient to ensure future water access, highlighting the need for implementing drastic mitigation actions.
The Influence of School Factors on Students’ Mathematics Achievements in Trends in International Mathematics and Science Study (TIMSS) in Abu Dhabi Emirate Schools
Authors: Wardat Yousef , Belbase Shashidhar , Tairab Hassan , Takriti Rachel Alison , Efstratopoulou Maria , Dodeen Hamza
Published: June 2022

This study aimed to explore school factors that influence students’ achievements in Trends in International Mathematics and Science Study (TIMSS) in schools in the Emirate of Abu Dhabi, in the United Arab Emirates. The study sample for TIMSS 2015 consisted of 4838 students in eighth grade; 2172 girls, 2666 boys, and 156 schools from Abu Dhabi attended and participated in TIMSS 2015. Principal component analysis (PCA) was run on 77 items of school questionnaires administered to school principals to provide information about the school contexts for teaching and learning. The five factors from the school questionnaire were general school resources, school discipline and safety, parental support, principal experience and education, and library and instruction resources. Multiple regression models were implemented to examine the impact of school factors on student achievement in TIMSS 2015. The models are statistically significant, indicating that they fit the data well. This also demonstrates a significant linear relationship between students’ achievement in TIMSS 2015 and the variables related to school factors.
The Performance Enhancement of PMOSFETs and Inverter Chains at Low Temperature and Low Voltage by Removing Plasma-Damaged Layers
Authors: Song Junhwa , Lee Eunsun , Hong Seungho , Kim Jihun , Oh Jeonghoon , Choi Byoungdeog
Published: June 2022

In this work we report on the improvement in cold temperature characteristics of PMOSFETs and inverter circuits by removing the plasma-damaged layer of the source/drain contacts. We removed the plasma-induced damage on the Si using a simple in situ Si soft treatment technique. We found by transmission electron microscope (TEM) analysis that the damaged amorphous layer reduced from 52 Å to 42 Å and 35 Å with a treatment time of 10 and 20 s, respectively. As a result, the resistances of both the n+ and p+ contacts decreased for all contact sizes and the standard deviations at the cold temperature were suppressed by 45%. At −25 °C, the saturation current of the PMOSFET increased by 3% and the propagation delay time (tPD) decreased by 2%. The tPD increases by 19.3% when the temperature decreases from 85 °C to −25 °C, and the operating voltage decreases from 1.2 V to 0.95 V at the same time. However, this increase can be reduced to 17% by applying the soft treatment for 10 s. This simple and short time process will be considered essential for both mobile applications and automotive applications of dynamic random access memory (DRAM) devices requiring a low-voltage and low-temperature operation.
Research on Energy Management Strategy of Electric Vehicle Hybrid System Based on Reinforcement Learning
Authors: Cheng Yu , Xu Ge , Chen Qihong
Published: June 2022

From the perspective of energy management, the demand power of a hybrid electric vehicle driving under random conditions can be considered as a random process, and the Markov chain can be used for modeling. In this article, an energy management strategy based on reinforcement learning with real-time updates is proposed to reasonably allocate the energy flow of the hybrid power system under unknown working conditions. The hybrid system is powered by a supercapacitor and a lithium battery, which uses the characteristics of each component to reduce the energy loss of the system, reduce the rate of change of the lithium battery current, and prolong the service life of the components. The strategy takes the change of the transition probability matrix under real-time working conditions as the basis. The system judges whether it is necessary to use the new transition probability to calculate and update the energy management strategy of the system by calculating the Pearson similarity between the transition probability matrix at the current time and previous time. The simulation results validate the proposed method.
Hunting Energy Bugs in Embedded Systems: A Software-Model-In-The-Loop Approach
Authors: Schaarschmidt Marco , Uelschen Michael , Pulvermüller Elke
Published: June 2022

Power consumption has become a major design constraint, especially for battery-powered embedded systems. However, the impact of software applications is typically considered in later phases, where both software and hardware parts are close to their finalization. Power-related issues must be detected in early stages to keep the development costs low, satisfy time-to-market, and avoid cost-intensive redesign loops. Moreover, the variety of hardware components, architectures, and communication interfaces make the development of embedded software more challenging. To manage the complexity of software applications, approaches such as model-driven development (MDD) may be used. This article proposes a power-estimation approach in MDD for software application models in early development phases. A unified modeling language (UML) profile is introduced to model power-related properties of hardware components. To determine the impact of software applications, we defined two analysis methods using simulation data and a novel in-the-loop concept. Both methods may be applied at different development stages to determine an energy trace, describing the energy-related behavior of the system. A novel definition of energy bugs is provided to describe power-related misbehavior. We apply our approach to a sensor node example, demonstrate an energy bug detection, and compare the runtime and accuracy of the analysis methods.
Study and Optimization of Transmission Characteristics of the Magnetically Coupled Resonant Wireless Transmission System
Authors: Wen Chunming , Chen Minbo , Xu Qing
Published: June 2022

The topology and parameter characteristics of the wireless energy transmission system are the main factors affecting the system’s performance. A series–parallel–series–parallel (spsp) topology for magnetically coupled wireless energy transmission is proposed to address the problems of low efficiency and low output power when transmitting electrical energy in the conventional magnetically coupled topology. The spsp topology is compared with the conventional topology based on circuit theory, and the two structures are modeled, characterized, and verified in detail. Simulations and tests are performed for the transmission conditions, an improved Gray Wolf optimization algorithm is proposed, and a physical system is built. Experiments show that the spsp structure is superior near the designed circuit parameters when the network works in a resonant state. The improved Gray Wolf optimization algorithm is then used to find the optimal parameters, and the transmission efficiency reaches 90.53%, which effectively improves the transmission performance of the system. The established physical system utilizes the optimized parameters for coil structure and coil offset experiments, and the average transmission efficiency is 83.75%, with an error of 6.78% calculated by data measurement. The rationality of the proposed structure and the correctness of the simulation parameter design method are verified, and it is hoped that the proposed system and circuit structure in this paper will provide a reference for the design of a magnetically coupled wireless energy transmission system.
Implementation of a Novel Tabu Search Optimization Algorithm to Extract Parasitic Parameters of Solar Panel
Authors: Repalle Naveena Bhargavi , Sarala Pullacheri , Mihet-Popa Lucian , Kotha Shashidhar Reddy , Rajeswaran Nagalingam
Published: June 2022

The aging of PV cells reduces their electrical performance i.e., the parasitic parameters are introduced in the solar panel. The shunt resistance (RSh), series resistance (RS), photo current (IPh), diode current (Id), and diffusion constant (a1) are known as parasitic or extraction parameters. Cracks and hotspots reduce the performance of PV cells and result in poor V–I characteristics. Certain tests are carried out over a long period of time to determine the quality of solar cells; for example, 1000 h of testing is comparable to 20 years of operation. The extraction of solar parameters is important for PV modules. The Tabu Search Optimization (TSO) algorithm is a robust meta-heuristic algorithm that was employed in this study for the extraction of parasitic parameters. Particle Swarm Optimization (PSO) and a Genetic lgorithm (GA), as well as other well-known optimization methods, were used to test the proposed method’s correctness. The other approaches included the lightning search algorithm (LSA), gravitational search algorithm (GSA), and pattern search (PS). It can be concluded that the TSO approach extracts all six parameters in a reasonably short period of time. The work presented in this paper was developed and analyzed using a MATLAB-Simulink software environment.
Permeability Models of Hydrate-Bearing Sediments: A Comprehensive Review with Focus on Normalized Permeability
Authors: Xu Jianchun , Bu Ziwei , Li Hangyu , Wang Xiaopu , Liu Shuyang
Published: June 2022

Natural gas hydrates (NGHs) are regarded as a new energy resource with great potential and wide application prospects due to their tremendous reserves and low CO2 emission. Permeability, which governs the fluid flow and transport through hydrate-bearing sediments (HBSs), directly affects the fluid production from hydrate deposits. Therefore, permeability models play a significant role in the prediction and optimization of gas production from NGH reservoirs via numerical simulators. To quantitatively analyze and predict the long-term gas production performance of hydrate deposits under distinct hydrate phase behavior and saturation, it is essential to well-establish the permeability model, which can accurately capture the characteristics of permeability change during production. Recently, a wide variety of permeability models for single-phase fluid flowing sediment have been established. They typically consider the influences of hydrate saturation, hydrate pore habits, sediment pore structure, and other related factors on the hydraulic properties of hydrate sediments. However, the choice of permeability prediction models leads to substantially different predictions of gas production in numerical modeling. In this work, the most available and widely used permeability models proposed by researchers worldwide were firstly reviewed in detail. We divide them into four categories, namely the classical permeability models, reservoir simulator used models, modified permeability models, and novel permeability models, based on their theoretical basis and derivation method. In addition, the advantages and limitations of each model were discussed with suggestions provided. Finally, the challenges existing in the current research were discussed and the potential future investigation directions were proposed. This review can provide insightful guidance for understanding the modeling of fluid flow in HBSs and can be useful for developing more advanced models for accurately predicting the permeability change during hydrate resources exploitation.
Probing the Effect of Governance of Tourism Development, Economic Growth, and Foreign Direct Investment on Carbon Dioxide Emissions in Africa: The African Experience
Authors: Agyeman Fredrick Oteng , Zhiqiang Ma , Li Mingxing , Sampene Agyemang Kwasi , Dapaah Malcom Frimpong , Kedjanyi Emmanuel Adu Gyamfi , Buabeng Paul , Li Yiyao , Hakro Saifullah , Heydari Mohammad
Published: June 2022

The environmental repercussions of extensive carbon dioxide (CO2) emissions on the environment are crucial for policymakers and scholars. The repercussions of and connection between economic growth (ECG), tourism (TOUR), and foreign direct investment (FDI) on CO2 emission mitigation have been measured and argued from empirical and theoretical perspectives by scholars. Notwithstanding, the extant body of knowledge has failed to incorporate and investigate the function of governance in decarbonizing tourism activities and FDI from CO2 emissions to attain a healthy and quality environment in Africa. Hence, this current research investigates governance’s role in the reduction processes of CO2 emissions grounded in environmental Kuznets curve (EKC) conceptual assumptions for panel data spanning 2000 through 2020 for 27 African countries. This research utilized the Westerlund panel cointegration approach for the investigation of the cointegration of the selected variables. This study applied the Driscoll–Kraay regression approach for the long-term estimation. In addition, the dynamic ordinary least squares (DOLS) and the pooled mean group (PMG) were used for robustness checks. The findings of this research indicated that the governance (GOV) indicators employed have a statistically significant effect on the CO2 emission reduction. Besides, this study found that the appreciation of the income of the nations gives credence to the formation of the EKC theory and contributes to the decline in CO2 emissions within the selected African nations. The findings revealed that tourism, FDI, ECG, and GOV are positive and significant factors leading to increased CO2 emissions in Africa. Furthermore, the results showed that effective governance and control of FDI inflows and tourism activities can support decarbonization. These findings suggest the merits of governance in ensuring effective decarbonization policies of the environment, and policy suggestions are accordingly put forward.
The Trait of Extraversion as an Energy-Based Determinant of Entrepreneur’s Success—The Case of Poland
Authors: Janowski Andrzej , Szczepańska-Przekota Anna
Published: June 2022

The fact that personality traits play an important role when it comes to predicting people’s entrepreneurial behavior is currently indisputable. However, so far, the majority of subject literature has focused on employee characteristics in developed countries. To address this gap, research was conducted, including 188 entrepreneurs of small and medium enterprises (SME) and 21 highest-level employees in Poland—one of the countries with the most hostile and turbulent environment for entrepreneurial operations in the world. The five personality traits (Big Five) were evaluated using the 60-item scale. There were three objectives of this study: to identify the differences between entrepreneurs and the most effective, highest-level employees, in the context of personality trait intensities, to determine the level of specific trait(s) intensities (OCEAN) of an effective entrepreneur. Finally, to determine whether it is possible to construct a model based on BIG5 to estimate the probability of success as an entrepreneur. The research results imply there are significant differences between successful entrepreneurs and highly effective employees and their personality trait intensities, described in the BIG5 model. Moreover, it is possible to distinguish trait intensity ranges, determining the success as an entrepreneur. Finally, we constructed the empirically based model, which allows us to estimate the chances of an individual succeeding as an entrepreneur with only a 5% error rate. The main factor and common denominator of entrepreneurial effectiveness is the trait of extraversion. The findings of our study are particularly important for the renewable energy sector in Poland, as the last part of green energy implementing blockchain (e.g., the installation and maintenance of wind turbines and solar panels) is being undertaken, in vast majority, by independent contractors and SME owners (entrepreneurs).
About Tree Height Measurement: Theoretical and Practical Issues for Uncertainty Quantification and Mapping
Authors: De Petris Samuele , Sarvia Filippo , Borgogno-Mondino Enrico
Published: June 2022

Forest height is a fundamental parameter in forestry. Tree height is widely used to assess a site’s productivity both in forest ecology research and forest management. Thus, a precise height measure represents a necessary step for the estimation of carbon storage at the local, national, and global scales. In this context, error in height measurement necessarily affects the accuracy of related estimates. Ordinarily, forest height is surveyed by ground sampling adopting hypsometers. The latter suffers from many errors mainly related to the correct tree apex identification (not always well visible in dense stands) and to the measurement process itself. In this work, a statistically based operative method for estimating height measurement uncertainty (σH) was proposed using the variance propagation law. Some simulations were performed involving several combinations of terrain slope, tree height, and survey distances by modelling the σH behaviour and its sensitivity to such parameters. Results proved that σH could vary between 0.5 m and up to 20 m (worst case). Sensitivity analysis shows that terrain slopes and distance poorly affect σH, while angles are the main drivers of height uncertainty. Finally, to give a practical example of such deductions, tree height uncertainty was mapped at the global scale using Google Earth Engine and summarized per forest biomes. Results proved that tropical biomes have higher uncertainty (from 1 m to 4 m) while shrublands and tundra have the lowest (under 1 m).
Comparative Composition Structure and Selected Techno-Functional Elucidation of Flaxseed Protein Fractions
Authors: Qin Xiaopeng , Li Linbo , Yu Xiao , Deng Qianchun , Xiang Qisen , Zhu Yingying
Published: June 2022

This study aimed to comparatively elucidate the composition structure and techno-functionality of flaxseed protein isolate (FPI), globulin (FG), and albumin (FA) fractions. The results showed that FA possessed smaller particle dimensions and superior protein solubility compared to that of FG (p < 0.05) due to the lower molecular weight and hydrophobicity. FA and FG manifested lamellar structure and nearly spherical morphology, respectively, whereas FPI exhibited small lamellar strip structure packed by the blurring spheres. The Far-UV CD, FTIR spectrum, and intrinsic fluorescence confirmed more flexible conformation of FA than that of FG, followed by FPI. The preferential retention of free phenolic acids was observed for FA, leading to excellent antioxidant activities compared with that of FG in FPI (p < 0.05). FA contributed to the foaming properties of FPI, relying on the earlier interfacial adsorption and higher viscoelastic properties. FA displayed favorable emulsifying capacity but inferior stability due to the limited interfacial adsorption and deformation, as well as loose/porous interface. By comparison, an interlayer anchoring but no direct interface coating was observed for lipid droplets constructed by FG, thereby leading to preferable emulsion stability. However, FPI produced lipid droplets with dense interface owing to the effective migration of FA and FG from bulk phase, concomitant with the easy flocculation and coalescence. Thus, the techno-functionality of flaxseed protein could be tailed by modulating the retention of albumin fraction and specific phenolic acids.
Enhancing the Biological Activities of Food Protein-Derived Peptides Using Non-Thermal Technologies: A Review
Authors: Fadimu Gbemisola J. , Le Thao T. , Gill Harsharn , Farahnaky Asgar , Olatunde Oladipupo Odunayo , Truong Tuyen
Published: June 2022

Bioactive peptides (BPs) derived from animal and plant proteins are important food functional ingredients with many promising health-promoting properties. In the food industry, enzymatic hydrolysis is the most common technique employed for the liberation of BPs from proteins in which conventional heat treatment is used as pre-treatment to enhance hydrolytic action. In recent years, application of non-thermal food processing technologies such as ultrasound (US), high-pressure processing (HPP), and pulsed electric field (PEF) as pre-treatment methods has gained considerable research attention owing to the enhancement in yield and bioactivity of resulting peptides. This review provides an overview of bioactivities of peptides obtained from animal and plant proteins and an insight into the impact of US, HPP, and PEF as non-thermal treatment prior to enzymolysis on the generation of food-derived BPs and resulting bioactivities. US, HPP, and PEF were reported to improve antioxidant, angiotensin-converting enzyme (ACE)-inhibitory, antimicrobial, and antidiabetic properties of the food-derived BPs. The primary modes of action are due to conformational changes of food proteins caused by US, HPP, and PEF, improving the susceptibility of proteins to protease cleavage and subsequent proteolysis. However, the use of other non-thermal techniques such as cold plasma, radiofrequency electric field, dense phase carbon dioxide, and oscillating magnetic fields has not been examined in the generation of BPs from food proteins.
Particle Swarm Optimization Fractional Slope Entropy: A New Time Series Complexity Indicator for Bearing Fault Diagnosis
Authors: Li Yuxing , Mu Lingxia , Gao Peiyuan
Published: June 2022

Slope entropy (SlEn) is a time series complexity indicator proposed in recent years, which has shown excellent performance in the fields of medical and hydroacoustics. In order to improve the ability of SlEn to distinguish different types of signals and solve the problem of two threshold parameters selection, a new time series complexity indicator on the basis of SlEn is proposed by introducing fractional calculus and combining particle swarm optimization (PSO), named PSO fractional SlEn (PSO-FrSlEn). Then we apply PSO-FrSlEn to the field of fault diagnosis and propose a single feature extraction method and a double feature extraction method for rolling bearing fault based on PSO-FrSlEn. The experimental results illustrated that only PSO-FrSlEn can classify 10 kinds of bearing signals with 100% classification accuracy by using double features, which is at least 4% higher than the classification accuracies of the other four fractional entropies.
Spatially-Resolved Network Dynamics of Poly(vinyl alcohol) Gels Measured with Dynamic Small Angle Light Scattering
Authors: Dhakal Sujata , Chen Zehao , Estrin Daniel , Morozova Svetlana
Published: June 2022

Hydrogels are cross-linked polymer networks swollen in water. The large solvent content enables hydrogels to have unique physical properties and allows them to be used in diverse applications such as tissue engineering, drug delivery, and absorbents. Gel properties are linked to internal dynamics. While bulk gel dynamics have been studied extensively, how gel networks respond locally to deformation has yet to be understood. Here, poly(vinyl alcohol) (PVA) gels have been stretched to study the effects of deformation on gel dynamics parallel and perpendicular to the stretching direction using dynamic small angle light scattering (DSALS). The implementation of DSALS is described and compared to traditional DLS for PVA gels with different crosslink densities, ranging from 0.75–2%. Despite the orders of magnitude difference in the scattering vector, q, range of the techniques, the dynamics match, and the apparent elastic diffusion coefficient, DA increases linearly with the crosslink density for unstretched gels at a constant 2 wt% concentration. We observe that the elastic motion depends on the direction of stretch, decreasing perpendicular to stretching and increasing at parallel direction. Using DSALS can therefore be an effective tool to evaluate local hydrogel response to deformation.
Development of Transformation for Genome Editing of an Emerging Model Organism
Authors: Yamamoto Yutaka , Gerbi Susan A.
Published: June 2022

With the advances in genomic sequencing, many organisms with novel biological properties are ripe for use as emerging model organisms. However, to make full use of them, transformation methods need to be developed to permit genome editing. Here, we present the development of transformation for the fungus fly Bradysia (Sciara) coprophila; this may serve as a paradigm for the development of transformation for other emerging systems, especially insects. Bradysia (Sciara) has a variety of unique biological features, including locus-specific developmentally regulated DNA amplification, chromosome imprinting, a monopolar spindle in male meiosis I, non-disjunction of the X chromosome in male meiosis II, X chromosome elimination in early embryogenesis, germ-line-limited (L) chromosomes and high resistance to radiation. Mining the unique biology of Bradysia (Sciara) requires a transformation system to test mutations of DNA sequences that may play roles for these features. We describe a Bradysia (Sciara) transformation system using a modified piggyBac transformation vector and detailed protocols we have developed to accommodate Bradysia (Sciara) specific requirements. This advance will provide a platform for us and others in the growing Bradysia (Sciara) community to take advantage of this unique biological system. In addition, the versatile piggyBac vectors described here and transformation methods will be useful for other emerging model systems.
The Role of ACE, ACE2, and AGTR2 Polymorphisms in COVID-19 Severity and the Presence of COVID-19-Related Retinopathy
Authors: Jevnikar Kristina , Lapajne Luka , Petrovič Daniel , Meglič Andrej , Logar Mateja , Vidovič Valentinčič Nataša , Globočnik Petrovič Mojca , Cilenšek Ines , Mekjavić Polona Jaki
Published: June 2022

The proposed SARS-CoV-2-induced dysregulation of the renin-angiotensin-aldosterone (RAAS) system results in endothelial dysfunction and microvascular thrombosis. The retinal plexuses contain terminal vessels without anastomotic connections, making the retina especially susceptible to ischemia. This study aimed to determine the role of selected polymorphisms of genes in the RAAS pathway in COVID-19 severity and their association with the presence of COVID-19 retinopathy. 69 hospitalized patients in the acute phase of COVID-19 without known systemic comorbidities and 96 healthy controls were enrolled in this prospective cross-sectional study. The retina was assessed with fundus photography using a Topcon DRI OCT Triton (Topcon Corp., Tokyo, Japan) in the COVID-19 unit. Genotyping of selected polymorphisms in the genes for ACE (rs4646994), ACE2 (rs2285666), and AGTR2 (rs1403543) was performed. The COVID-19 group was divided into mild (n = 12) and severe (n = 57), and then further divided according to the presence of COVID-19 retinopathy (Yes, n = 50; No, n = 19). The presence of the AGTR2 rs1403543-AA genotype was associated with a 3.8-fold increased risk of COVID-19 retinopathy (p = 0.05). The genotype frequencies of selected gene polymorphisms were not significantly associated with either the presence of COVID-19 or its severity. This is the first study demonstrating a borderline association of the AGTR2 rs1403543-AA genotype with COVID-19 retinopathy in males; hence, the AGTR2 rs 1403543 A allele might represent a genetic risk factor for COVID-19 retinopathy in males.
Characterization of Chicken α2A-Adrenoceptor: Molecular Cloning, Functional Analysis, and Its Involvement in Ovarian Follicular Development
Authors: Jiang Biying , Cao Baolong , Zhou Zhichun , Li Zejiao , Lv Can , Zhang Jiannan , Zhang Heyuan , Wang Yajun , Li Juan
Published: June 2022

Adrenoceptors are suggested to mediate the functions of norepinephrine (NE) and epinephrine (EPI) in the central nervous system (CNS) and peripheral tissues in vertebrates. Compared to mammals, the functionality and expression of adrenoceptors have not been well characterized in birds. Here, we reported the structure, expression, and functionality of chicken functional α2A-adrenoceptor, named ADRA2A. The cloned chicken ADRA2A cDNA is 1335 bp in length, encoding the receptor with 444 amino acids (a.a.), which shows high amino acid sequence identity (63.4%) with its corresponding ortholog in humans. Using cell-based luciferase reporter assays and Western blot, we demonstrated that the ADRA2A could be activated by both NE and EPI through multiple signaling pathways, including MAPK/ERK signaling cascade. In addition, the mRNA expression of ADRA2A is found to be expressed abundantly in adult chicken tissues including thyroid, lung, ovary and adipose from the reported RNA-Seq data sets. Moreover, the mRNA expression of ADRA2A is also found to be highly expressed in the granulosa cells of 6–8 mm and F5 chicken ovarian follicles, which thus supports that ADRA2A signaling may play a role in ovarian follicular growth and differentiation. Taken together, our data provide the first proof that the α2A-adrenoceptor is functional in birds involving avian ovarian follicular development.