bluuebunny/crossref_metadata_2025 huggingface dataset:
Validation of the T-Lymphocyte Subset Index (TLSI) as a Score to Predict Mortality in Unvaccinated Hospitalized COVID-19 Patients
Authors: Di Lorenzo Andrea , Tedde Simona , Pace Pier Giorgio , Campogiani Laura , Ansaldo Lorenzo , Lodi Alessandra , Zordan Marta , Barreca Filippo , Caldara Federica , Rossi Benedetta , Imeneo Alessandra , Alessio Grazia , Crea Angela Maria Antonia , Checchi Davide , Malagnino Vincenzo , Teti Elisabetta , Coppola Luigi , Palmieri Raffaele , Buccisano Francesco , Andreoni Massimo , Sarmati Loredana , Iannetta Marco
Published: November 2022

Lymphopenia has been consistently reported as associated with severe coronavirus disease 2019 (COVID-19). Several studies have described a profound decline in all T-cell subtypes in hospitalized patients with severe and critical COVID-19. The aim of this study was to assess the role of T-lymphocyte subset absolute counts measured at ward admission in predicting 30-day mortality in COVID-19 hospitalized patients, validating a new prognostic score, the T-Lymphocyte Subset Index (TLSI, range 0–2), based on the number of T-cell subset (CD4+ and CD8+) absolute counts that are below prespecified cutoffs. These cutoff values derive from a previously published work of our research group at Policlinico Tor Vergata, Rome, Italy: CD3+CD4+ < 369 cells/μL, CD3+CD8+ < 194 cells/μL. In the present single-center retrospective study, T-cell subsets were assessed on admission to the infectious diseases ward. Statistical analysis was performed using JASP (Version 0.16.2. JASP Team, 2022, Amsterdam, The Netherlands) and Prism8 (version 8.2.1. GraphPad Software, San Diego, CA, USA). Clinical and laboratory parameters of 296 adult patients hospitalized because of COVID-19 were analyzed. The overall mortality rate was 22.3% (66/296). Survivors (S) had a statistically significant lower TLSI score compared to non-survivors (NS) (p < 0.001). Patients with increasing TLSI scores had proportionally higher rates of 30-day mortality (p < 0.0001). In the multivariable logistic analysis, the TLSI was an independent predictor of in-hospital 30-day mortality (OR: 1.893, p = 0.003). Survival analysis showed that patients with a TLSI > 0 had an increased risk of death compared to patients with a TLSI = 0 (hazard ratio: 2.83, p < 0.0001). The TLSI was confirmed as an early and independent predictor of COVID-19 in-hospital 30-day mortality.
Serum Cystatin C Levels Could Predict Rapid Kidney Function Decline in A Community-Based Population
Authors: Fang Wei-Ching , Chen Hsing-Yu , Chu Shao-Chi , Wang Po-Hsi , Lee Chin-Chan , Wu I-Wen , Sun Chiao-Yin , Hsu Heng-Jung , Chen Chun-Yu , Chen Yung-Chang , Wu Vin-Cent , Pan Heng-Chih
Published: November 2022

Background: Several biomarkers have been correlated with the prevalence and severity of chronic kidney disease (CKD); however, the association between biomarkers and rapid kidney function decline (RKFD) is unknown. This study aimed to evaluate the predictive performance of biomarkers to determine who is likely to develop RKFD in a healthy population. Methods: A community-based cohort of 2608 people residing in northern Taiwan were enrolled, and their renal function was followed annually from January 2014 to December 2019. The outcomes of interest were RKFD, defined as a 15% decrease in the estimated glomerular filtration rate (eGFR) within the first 4 years, and a decrease in eGFR without improvement in the fifth year. Clinical variables and potential predictors of RKFD, namely adiponectin, leptin, tumor necrosis factor-alpha, and cystatin C, were measured and analyzed. Results: The incidence of RKFD was 17.0% (105/619). After matching for age and sex at a 1:1 ratio, a total of 200 subjects were included for analysis. The levels of cystatin C and total vitamin D were significantly negatively correlated with eGFR. eGFR was negatively correlated with the levels of cystatin C and total vitamin D. Among the biomarkers, cystatin C showed the best predictive performance for RKFD (area under the receiver operating characteristic curve: 0.789). Lower serum cystatin C was associated with a higher rate of RKFD in healthy subjects. A generalized additive model showed that 0.82 mg/L was an adequate cut-off value of cystatin C to predict RKFD. Multivariable logistic regression analysis further indicated that low cystatin C and eGFR were independent predictors of the possibility of RKFD. Conclusions: Serum cystatin C level could predict the possibility of RKFD. We suggest that a low cystatin C level should be considered as a risk factor for RKFD in healthy subjects.
Characterization of Vascular Patterns Associated with Endothelial Glycocalyx Damage in Early- and Late-Onset Preeclampsia
Authors: Ziganshina Marina M. , Muminova Kamilla T. , Khasbiullina Nailia R. , Khodzhaeva Zulfiya S. , Yarotskaya Ekaterina L. , Sukhikh Gennady T.
Published: November 2022

This paper provides an assessment of molecular and functional changes in blood vessels, and a description of vascular patterns during preeclampsia (PE). Patients with normal pregnancy, and pregnancy complicated by PE at earlier (20–34 weeks) and later terms (≥34 weeks) underwent a 24 h monitoring of blood pressure, central hemodynamics, arterial stiffness, and myocardial function. The blood levels of the structural components of endothelial glycocalyx (eGC): syndecan-1 (SDC 1), heparan sulfate proteoglycan 2 (HSPG2), and hyaluronic acid (HA) were determined. In early-onset PE, the vascular pattern comprised changes in all structural components of eGCs, including transmembrane proteoglycans levels, and severe disorders of central hemodynamics, arterial stiffness, and myocardial changes, probably leading to more severe course of PE and the formation of morphological grounds for cardiovascular disorders. The vascular pattern in late-onset PE, including changes in HA levels, central hemodynamics, and myocardial function, may be a signal of potential cardiovascular disorder. PE may change adaptive hemodynamic responses to a pathological reaction affecting both arterial elasticity and the left ventricular myocardium, with its subsequent hypertrophy and decompensation, leading to a delayed development of cardiovascular disorders after PE. Further clinical studies of these indicators will possibly identify predictors of PE and long-term consequences of the disease.
Biomedical Applications of Plant Extract-Synthesized Silver Nanoparticles
Authors: Simon Sohail , Sibuyi Nicole Remaliah Samantha , Fadaka Adewale Oluwaseun , Meyer Samantha , Josephs Jamie , Onani Martin Opiyo , Meyer Mervin , Madiehe Abram Madimabe
Published: November 2022

Silver nanoparticles (AgNPs) have attracted a lot of interest directed towards biomedical applications due in part to their outstanding anti-microbial activities. However, there have been many health-impacting concerns about their traditional synthesis methods, i.e., the chemical and physical methods. Chemical methods are commonly used and contribute to the overall toxicity of the AgNPs, while the main disadvantages of physical synthesis include high production costs and high energy consumption. The biological methods provide an economical and biocompatible option as they use microorganisms and natural products in the synthesis of AgNPs with exceptional biological properties. Plant extract-based synthesis has received a lot of attention and has been shown to resolve the limitations associated with chemical and physical methods. AgNPs synthesized using plant extracts provide a safe, cost-effective, and environment-friendly approach that produces biocompatible AgNPs with enhanced properties for use in a wide range of applications. The review focused on the use of plant-synthesized AgNPs in various biomedical applications as anti-microbial, anti-cancer, anti-inflammatory, and drug-delivery agents. The versatility and potential use of green AgNPs in the bio-medicinal sector provides an innovative alternative that can overcome the limitations of traditional systems. Thus proving green nanotechnology to be the future for medicine with continuous progress towards a healthier and safer environment by forming nanomaterials that are low- or non-toxic using a sustainable approach.
PD1+CD8+ Cells Are an Independent Prognostic Marker in Patients with Head and Neck Cancer
Authors: Pokrývková Barbora , Grega Marek , Klozar Jan , Vencálek Ondřej , Nunvář Jaroslav , Tachezy Ruth
Published: November 2022

Head and neck squamous cell carcinomas (HNSCCs) belong to a group of diverse tumors, which can be induced by infection with human papillomavirus (HPV) or tobacco and alcohol consumption. The viral etiology of HNSCC relates to better clinical outcomes reflecting a different immune system response. Here, we retrospectively analyzed 97 tissue samples from oral and oropharyngeal carcinomas associated and non-associated with HPV infection using multispectral fluorescent immunohistochemistry. To evaluate the immune cell infiltration in tumor and stroma compartments, we designed four panels of four to five antibodies. We detected more T lymphocytes in the stroma, compared to the tumor parenchyma. In HPV positive (HPV+) in comparison to HPV negative (HPV−) tumors, higher counts of CD3+CD4+, CD3+CD8+, PD1+CD4+, PD1+CD8+ T cells, and ICOS− Treg cells were detected while more ICOS+ Treg cells and CTLA4+CD4+ T cells were observed in HPV− than in HPV+ tumors. The results of the univariate and multivariate analyses confirmed the predominant impact of HPV status on prognosis. More importantly, the number of CD8+PD-1+ T cells was identified as an independent factor, influencing the overall and/or disease-specific survival of patients with oral cavity or oropharyngeal carcinomas.
Current Applications of Artificial Intelligence to Classify Cervical Lymph Nodes in Patients with Head and Neck Squamous Cell Carcinoma—A Systematic Review
Authors: Santer Matthias , Kloppenburg Marcel , Gottfried Timo Maria , Runge Annette , Schmutzhard Joachim , Vorbach Samuel Moritz , Mangesius Julian , Riedl David , Mangesius Stephanie , Widmann Gerlig , Riechelmann Herbert , Dejaco Daniel , Freysinger Wolfgang
Published: November 2022

Locally-advanced head and neck squamous cell carcinoma (HNSCC) is mainly defined by the presence of pathologic cervical lymph nodes (LNs) with or without extracapsular spread (ECS). Current radiologic criteria to classify LNs as non-pathologic, pathologic, or pathologic with ECS are primarily shape-based. However, significantly more quantitative information is contained within imaging modalities. This quantitative information could be exploited for classification of LNs in patients with locally-advanced HNSCC by means of artificial intelligence (AI). Currently, various reviews exploring the role of AI in HNSCC are available. However, reviews specifically addressing the current role of AI to classify LN in HNSCC-patients are sparse. The present work systematically reviews original articles that specifically explore the role of AI to classify LNs in locally-advanced HNSCC applying Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines and the Study Quality Assessment Tool of National Institute of Health (NIH). Between 2001 and 2022, out of 69 studies a total of 13 retrospective, mainly monocentric, studies were identified. The majority of the studies included patients with oropharyngeal and oral cavity (9 and 7 of 13 studies, respectively) HNSCC. Histopathologic findings were defined as reference in 9 of 13 studies. Machine learning was applied in 13 studies, 9 of them applying deep learning. The mean number of included patients was 75 (SD ± 72; range 10–258) and of LNs was 340 (SD ± 268; range 21–791). The mean diagnostic accuracy for the training sets was 86% (SD ± 14%; range: 43–99%) and for testing sets 86% (SD ± 5%; range 76–92%). Consequently, all of the identified studies concluded AI to be a potentially promising diagnostic support tool for LN-classification in HNSCC. However, adequately powered, prospective, and randomized control trials are urgently required to further assess AI’s role in LN-classification in locally-advanced HNSCC.
Reaction Characteristics of Ni-Based Catalyst Supported by Al2O3 in a Fluidized Bed for CO2 Methanation
Authors: Hwang Byungwook , Ngo Son Ich , Lim Young-Il , Seo Myung Won , Park Sung Jin , Ryu Ho-Jung , Nam Hyungseok , Lee Doyeon
Published: November 2022

CO2 methanation is a promising technology to store renewable energy by converting carbon dioxide with green hydrogen into methane, which is known as power to gas (PtG). In this study, CO2 methanation performance of a Ni/Al2O3 catalyst was investigated in a bubbling fluidized bed (BFB) and the axial gas concentration, temperature, and CO2 conversion were densely analyzed. Moreover, a modified reaction kinetic model was proposed, and the results were compared with experimental data. The bed temperature increased by 11 °C from 340 °C to 351 °C within the first 30 mm of the fluidized bed. The CO2 conversion was approximately 90% within 50 mm from the bottom of the reactor and was maintained above this height. The Ni/Al2O3 catalyst exhibited the highest CO2 conversion (95%) at 320 °C. Using a simple plug-flow reactor model, three optimized kinetic modification factors (1.5094, 0.0238, and 0.2466) were used to fit the experimental data. The hydrodynamic effects significantly influenced the chemical reaction kinetics of the BFB.
Green Hydrothermal Synthesis of Zinc Oxide Nanoparticles for UV-Light-Induced Photocatalytic Degradation of Ciprofloxacin Antibiotic in an Aqueous Environment
Authors: Batterjee Maha G. , Nabi Arshid , Kamli Majid Rasool , Alzahrani Khalid Ahmed , Danish Ekram Y. , Malik Maqsood Ahmad
Published: November 2022

The design and development of new cost-effective, clean, and efficient synthesis procedures for the synthesis of nanoparticles have recently become an intriguing research topic with broad implications. This study aimed to develop an eco-friendly biogenic method that uses minimum nontoxic chemicals to yield ZnO nanoparticles with enhanced capabilities for degradation of pharmaceutical by-products. The present study used black dried lemon peel aqueous extract as a biological stabilizing agent to prepare pure and stable zinc oxide nanoparticles (LP-ZnO NPs). The surface morphology, elemental composition, crystalline properties, size, optical properties, the role of functional groups in stabilization, capping, and the thermal stability of LP-ZnO NPs were investigated using scanning electron microscopy equipped with energy dispersive X-ray (SEM-EDX), X-ray diffraction (XRD), UV–visible diffuse reflectance spectroscopy (UV-DRS), PL, Fourier transform infrared (FTIR), Raman spectra, and thermogravimetric (TGA) analyses. Multiphoton resonances were observed in LP-ZnO NPs along the crystalline structure as per Raman analysis. The developed LP-ZnO NPs were thermally stable at an annealing temperature of 500 °C with a weight loss of 53%. Photodegradation of antibiotic ciprofloxacin was observed in the presence of UV light via LP-ZnO NPs (serving as photocatalyst). In addition, in optimal reaction media, the biogenic LP-ZnO NPs retained improved photocatalytic performance toward ciprofloxacin. Meanwhile, in the photodegradation process of CPI molecules via ZnO as a photocatalyst, the optimum catalytic dose, concentration of CIP molecules, and pH were attained at 10 mg, 2 × 10−5 M, and pH 8, respectively. The aim of this research work was to develop a simple, affordable photocatalytic technique for the photodegradation of antibiotics in aqueous media. The photocatalytic process was performed under different experimental conditions, including varying catalytic doses, ciprofloxacin concentrations, and pH of the reaction mixture.
Electrochemical Reduction of Carbon Dioxide: Recent Advances on Au-Based Nanocatalysts
Authors: Chen Qisi , Tsiakaras Panagiotis , Shen Peikang
Published: November 2022

The electrocatalytic reduction of CO2 to other high value-added chemicals under ambient conditions is a promising and ecofriendly strategy to achieve sustainable carbon recycling. However, the CO2 reduction reaction (CO2RR) is still confronted with a large number of challenges, such as high reaction overpotential and low product selectivity. Therefore, the rapid development of appropriate electrocatalysts is the key to promoting CO2 electroreduction. Over the past few decades, Au-based nanocatalysts have been demonstrated to be promising for the selective CO2RR to CO owing to their low reaction overpotential, good product selectivity, high Faraday efficiency and inhibition of the hydrogen evolution reaction. In this respect, this review first introduces the fundamentals of the electrochemical reduction of CO2 and then focuses on recent accomplishments with respect to Au-based nanocatalysts for CO2RR. The manipulation of various factors, e.g., the nanoporous structure, nanoparticle size, composition, morphology, support and ligand, allows for the identification of several clues for excellent Au-based nanocatalysts. We hope that this review will offer readers some important insights on Au-based catalyst design and provide new ideas for developing robust electrocatalysts.
A Theoretical and Experimental Approach to the Analysis of Hydrogen Generation and Thermodynamic Behavior in an In Situ Heavy Oil Upgrading Process Using Oil-Based Nanofluids
Authors: Medina Oscar E. , Céspedes Santiago , Zabala Richard D. , Franco Carlos A. , Pérez-Cadenas Agustín F. , Carrasco-Marín Francisco , Lopera Sergio H. , Cortés Farid B. , Franco Camilo A.
Published: November 2022

This study aims to show a theoretical and experimental approach to the analysis of hydrogen generation and its thermodynamic behavior in an in situ upgrading process of heavy crude oil using nanotechnology. Two nanoparticles of different chemical natures (ceria and alumina) were evaluated in asphaltene adsorption/decomposition under a steam atmosphere. Then, a nanofluid containing 500 mg·L−1 of the best-performing nanoparticles on a light hydrocarbon was formulated and injected in a dispersed form in the steam stream during steam injection recovery tests of two Colombian heavy crude oils (HO1 and HO2). The nanoparticles increased the oil recovery by 27% and 39% for HO1 and HO2 regarding the steam injection. The oil recovery at the end of the displacement test was 85% and 91% for HO1 and HO2, respectively. The recovered crude oil showed an increment in API° gravity from 12.4° and 12.1° to 18.5° and 29.2° for HO1 and HO2, respectively. Other properties, such as viscosity and content of asphaltenes and resins with high molecular weight, were positively modified in both crude oils. The fugacity of H2 was determined between the reservoir and overburden pressure and different temperatures, which were determined by the thermal profiles in the displacement test. The fugacity was calculated using the application of virial equations of state with mixing rules based on the possible intermolecular interactions between the components. Hydrogen acquired a higher chemical potential via nanoparticle presence. However, the difference in H2 fugacity between both points is much higher with nanoparticles, which means that hydrogen presents a lower tendency to migrate by diffusion to the high-pressure point. The difference between HO1 and HO2 lies mainly in the fact that the pressure difference between the reservoir and the overburden pressure is greater in HO2; therefore, the difference in fugacity is greater when the pressure differential is greater.
Screening Questionnaire for Vitamin D Insufficiency in Children with Obesity
Authors: Calcaterra Valeria , Cena Hellas , Biino Ginevra , Grazi Roberta , Bortoni Giulio , Braschi Valentina , Tomasinelli Chiara Elena , Schneider Laura , Zuccotti Gianvincenzo
Published: November 2022

Non-invasive screening tools to identify children at high risk of vitamin D (VitD) deficiency are proactive measures in preventive care. Recently, a validated questionnaire (Evaluation dEficieNCy Questionnaire, EVIDENCe-Q) for identifying newly diagnosed VitD-insufficient adults has been developed. We tested the EVIDENCe-Q modified for children with obesity and evaluated the correlation between VitD and questionnaire scores to adapt this tool to the pediatric population. We enrolled 120 children with obesity (BMI ≥ 2). Clinical evaluation and VitD levels were considered. The modified EVIDENCe-Q included information regarding factors affecting control of VitD, with scores ranging between 0 (best) and 36 (worst). VitD and adiposity indices were inversely correlated. The threshold values for identifying severe deficiency (<10 mg/dL), deficiency (<20 mg/dL) and insufficiency (<30 mg/dL) were scores of 21, 19 and 23, respectively. According to those thresholds, the prevalence of severe deficiency, deficiency and insufficiency was 47.5%, 69.2% and 23.3%, respectively; the best accuracy was obtained with a questionnaire score cut-off of 19 for the VitD deficiency level. A novel simple screening tool such as the modified EVIDENCe-Q would be useful in clinical practice to identify potential cases of hypovitaminosis D and select at-risk patients. Considering the limited accuracy and specificity of our results, for the pediatric population a dedicated tool should be created. Phases of childhood and the role of adipose tissue could be considered in the definition of a questionnaire intended for pediatric patients with obesity.
Biological Activities of Paper Mulberry (Broussonetia papyrifera): More than a Skin-Lightening Agent
Authors: Nguyen Ly Thi Huong
Published: November 2022

Background: Paper mulberry is one of the most common skin-lightening agents in the beauty industry due to its strong anti-tyrosinase activity. This narrative review aims to summarize the chemical composition, biological activities, and applications of paper mulberry in cosmetics. Method: The literature for this article was acquired from the PubMed, Web of Science, and Google Scholar databases before September 2022. The keywords for searching included “paper mulberry”, “Broussonetia papyrifera”, “skin-lightening”, “skin-whitening”, “depigmentation”, “pharmacological activity”, and “biological activity”. Results: Paper mulberry consists of various components, including flavonoids, tannins, alkaloids, phenols, saponins, coumarins, glycosides, and polysaccharides, which possess a wide range of pharmacological properties. Apart from its anti-tyrosinase activity, paper mulberry and its compounds exhibited anti-inflammatory, antioxidant, antimicrobial, antiviral, anticancer, antidiabetic, anticholinesterase, antigout, antinociceptive, and hepatoprotective effects. Phenols and flavonoids were demonstrated to be the main contributors to the biological activities of paper mulberry. Paper mulberry is widely applied in cosmetics for skin lightening and skin moisturizing purposes and shows potential for application in hair care products due to the hair nourishing effects. The safety of paper mulberry for topical application was proven in clinical studies. Conclusion: The current review provides a better understanding of paper mulberry’s properties and allows us to extend the application of this plant and its bioactive components in cosmetics.
Alternative Utilization of Vegetable Crop: Pumpkin Polysaccharide Extract and Their Efficacy on Skin Hydration
Authors: Chanpirom Setinee , Saewan Nisakorn , Sripisut Tawanun
Published: November 2022

Traditional pumpkin (Cucurbita moschata) and Japanese pumpkin (C. maxima) consist of natural polysaccharides. From a scientific basis, natural polysaccharides could be applied to improve hydration in the cosmetic field. The purified polysaccharide was extracted and deproteinized with the CaCl2 method. Japanese pumpkin showed the higher value of physicochemical properties including yield (12.96 ± 0.60%), total polysaccharide content (0.89 ± 0.04 mg/mL), swelling capacity (4.00 ± 0.00%), swelling index (1.04 ± 0.00%), solubility (126.67 ± 5.77%), viscosity (1.25 ± 0.00 cps), water capacity (0.93 ± 0.15 g/g) and oil absorption capacity (5.93 ± 0.06 g/g) than traditional pumpkin. Additionally, Japanese pumpkin (IC50 9.30 ± 0.58 µg/mL) provided higher antioxidant activity by DPPH assay than traditional pumpkin (IC50 9.98 ± 0.25 µg/mL). The evaluation of efficacy on skin hydration in fifteen Thai volunteers indicated that Japanese pumpkin showed non-skin irritation. An extract concentration of 0.05–0.1% showed a significantly increased effect in moisturizing ability according to concentration (p < 0.05). This result supported that it was safe and effective to use as a moisturizer for cosmetic products.
Barriers Facing Direct Support Professionals When Supporting Older Adults Presenting with Intellectual Disabilities and Unusual Dementia-Related Behavior: A Multi-Site, Multi-Methods Study
Authors: Ebbing Karsten , von Gunten Armin , Guinchat Vincent , Georgescu Dan , Bersier Taree , Moad Djamel , Verloo Henk
Published: November 2022

Introduction: Increased life expectancy among people with intellectual disabilities (ID) raises the risk of their diagnosis being superimposed by behavioral and psychological symptoms of dementia (BPSD). The difficulties facing direct support professionals dealing with this is an emerging, under-investigated issue. The study investigates direct support professionals’ perceptions and experiences of their daily support for aging people with ID presenting with superimposed BPSD. Method: Twenty-four direct support professionals from long-term care facilities responded to clinical vignettes and attended focus groups conducted to investigate perceptions and lived experiences of the barriers and struggles they faced. Results: Direct support professionals’ reactions to vignettes revealed their difficulties recognizing BPSD superimposed on the known challenging behaviors of people with ID. Focus groups highlighted daily struggles with BPSD, the lack of knowledge about detecting and dealing with them, and associated somatic and psychopathological diseases of aging. Conclusion: Improved knowledge transfer about good practices for person-centered support to aging people with ID presenting with BPSD is strongly recommended.
Testing the Intercept of a Balanced Predictive Regression Model
Authors: Wang Qijun , Liu Xiaohui , Fan Yawen , Peng Ling
Published: November 2022

Testing predictability is known to be an important issue for the balanced predictive regression model. Some unified testing statistics of desirable properties have been proposed, though their validity depends on a predefined assumption regarding whether or not an intercept term nevertheless exists. In fact, most financial data have endogenous or heteroscedasticity structure, and the existing intercept term test does not perform well in these cases. In this paper, we consider the testing for the intercept of the balanced predictive regression model. An empirical likelihood based testing statistic is developed, and its limit distribution is also derived under some mild conditions. We also provide some simulations and a real application to illustrate its merits in terms of both size and power properties.
The Social Capital and Cash Holdings in an Emerging Economy
Authors: Homayoun Saeid , Seifzadeh Maryam
Published: November 2022

The present study aims to evaluate the relationship between social capital and cash holdings in firms. The population under study comprises all listed companies on the Tehran Stock Exchange. A total of 175 firms (1050 year-firm) were selected from 2014 to 2020 to evaluate the relationship between variables using the systematic elimination method. Moreover, the moderating role of financial reporting quality in the relationship between social capital and cash holdings was also studied. This paper used multivariable linear regression (panel data) and the EViews software to implement the study’s objectives. The present study results show a negative relationship between the social capital of firms and cash holdings and a positive association between social capital and financial reporting quality. In other words, cash holdings drop with the increase in social capital. Further, financial reporting quality improves with the increase in social capital. The financial reporting quality moderates the relationship between the social capital of firms and cash holdings. This paper indicates that the region’s social capital, where the firm is located, has a significant role in contributing to its cash value. The current study is the first to assess social capital structure in the cash holdings literature. The impacts of social capital contribute to financial outputs. Social capital has a positive economic result against strong cooperation norms and dense social networks. Few studies analyzed the effect of social capital on firms’ decision making. In this area, the present study contributes to the literature development and the impact of social capital on firms’ results.
The Impact of Oil Price and Oil Volatility Index (OVX) on the Exchange Rate in Sub-Saharan Africa: Evidence from Oil Importing/Exporting Countries
Authors: Korley Maud , Giouvris Evangelos
Published: November 2022

The Theory demonstrates that oil price and oil volatility (OVX) are significant determinants of economic activity; however, studies seldom consider both variables in the oil–exchange rate nexus and ignore the distributional heterogeneity of the exchange rate. We investigate their joint effect and employ both the quantile regression and Markov switching models to address this. We differentiate between positive/negative shocks and control for the effect of the global financial crisis in 2008 and the COVID-19 pandemic in 2020. We observe that OVX shocks significantly impact the exchange rate for all countries whereas, oil price shocks only affect the exchange rate of oil importing countries. Rising (falling) OVX causes the local currency to depreciate (appreciate). The impact of rising or falling OVX is the same for oil importing and oil exporting countries whereas the impact of rising and falling oil price varies. The impact of oil price and OVX on exchange rate is affected by market conditions. The exchange rate responds to oil price and OVX mostly at lower quantiles (bearish markets) for all countries, which reveals investors sensitivity. In contrast, a weak to no significant response is observed at the higher quantiles (bullish market). Our results are robust in model selection (Markov switching models).
What Matters for Boys Does Not Necessarily Matter for Girls: Gender-Specific Relations between Perceived Self-Determination, Engagement, and Performance in School Mathematics
Authors: Hofer Sarah Isabelle , Reinhold Frank , Hulaj Dilan , Koch Marco , Heine Jörg-Henrik
Published: November 2022

While math performance does not seem to differ systematically between males and females, it is one of the subjects that is consistently perceived as “male” with girls regularly reporting lower levels of motivation and less positive attitudes than boys. This study aimed to uncover gender-specific relations between perceived self-determination, engagement, and performance in school mathematics that might help to better understand this discrepancy. In an online study, we hence assessed perceived competence and autonomy support, social relatedness, cognitive and behavioral engagement, math performance as well as sustained attention as a basic cognitive prerequisite in a sample of N = 221 Seventh-Grade students from southern Germany (Mage = 12.84 years, SDage = 0.55, Nfemales = 115). As expected, we found no gender differences in math performance. In multiple group path analyses, perceived autonomy support was the most consistent predictor of cognitive and behavioral engagement for both girls and boys. While it did not affect math performance directly, we found significant indirect effects via cognitive engagement for girls, and via behavioral engagement for boys, whereas competence support in the math classroom, which female students perceived as significantly lower than male students, negatively predicted only girls’ performance, sustained attention explained a considerable part of boys’ math performance. Girls seem to experience competence support less often than boys, and if they do, we assume it to be in response to low performance rather than to encourage high competence and nurture talent. Our results suggest promising avenues for future research and implications for math classrooms.
Performance Investigation of Principal Component Analysis for Intrusion Detection System Using Different Support Vector Machine Kernels
Authors: Almaiah Mohammed Amin , Almomani Omar , Alsaaidah Adeeb , Al-Otaibi Shaha , Bani-Hani Nabeel , Hwaitat Ahmad K. Al , Al-Zahrani Ali , Lutfi Abdalwali , Awad Ali Bani , Aldhyani Theyazn H. H.
Published: November 2022

The growing number of security threats has prompted the use of a variety of security techniques. The most common security tools for identifying and tracking intruders across diverse network domains are intrusion detection systems. Machine Learning classifiers have begun to be used in the detection of threats, thus increasing the intrusion detection systems’ performance. In this paper, the investigation model for an intrusion detection systems model based on the Principal Component Analysis feature selection technique and a different Support Vector Machine kernels classifier is present. The impact of various kernel functions used in Support Vector Machines, namely linear, polynomial, Gaussian radial basis function, and Sigmoid, is investigated. The performance of the investigation model is measured in terms of detection accuracy, True Positive, True Negative, Precision, Sensitivity, and F-measure to choose an appropriate kernel function for the Support Vector Machine. The investigation model was examined and evaluated using the KDD Cup’99 and UNSW-NB15 datasets. The obtained results prove that the Gaussian radial basis function kernel is superior to the linear, polynomial, and sigmoid kernels in both used datasets. Obtained accuracy, Sensitivity, and, F-measure of the Gaussian radial basis function kernel for KDD CUP’99 were 99.11%, 98.97%, and 99.03%. for UNSW-NB15 datasets were 93.94%, 93.23%, and 94.44%.
Efficient System Identification of a Two-Wheeled Robot (TWR) Using Feed-Forward Neural Networks
Authors: Khan Muhammad Aseer , Baig Dur-e-Zehra , Ali Husan , Ashraf Bilal , Khan Shahbaz , Wadood Abdul , Kamal Tariq
Published: November 2022

System identification of a Two-Wheeled Robot (TWR) through nonlinear dynamics is carried out in this paper using a data-driven approach. An Artificial Neural Network (ANN) is used as a kinematic estimator for predicting the TWR’s degree of movement in the directions of x and y and the angle of rotation Ψ along the z-axis by giving a set of input vectors in terms of linear velocity ‘V’ (i.e., generated through the angular velocity ‘ω’ of a DC motor). The DC motor rotates the TWR’s wheels that have a wheel radius of ‘r’. Training datasets are achieved via simulating nonlinear kinematics of the TWR in a MATLAB Simulink environment by varying the linear scale sets of ‘V’ and ‘(r ± ∆r)’. Perturbation of the TWR’s wheel radius at ∆r = 10% is introduced to cater to the robustness of the TWR wheel kinematics. A trained ANN accurately modeled the kinematics of the TWR. The performance indicators are regression analysis and mean square value, whose achieved values met the targeted values of 1 and 0.01, respectively.
The Impact of the Ukrainian War on Stock and Energy Markets: A Wavelet Coherence Analysis
Authors: Basdekis Charalampos , Christopoulos Apostolos , Katsampoxakis Ioannis , Nastas Vasileios
Published: November 2022

This study attempts to examine the existence of interdependencies between specific stock market indices, exchange rates and crude oil for the period January 2021 to July 2022 with daily data. In the period we have chosen, the post-vaccination phase against COVID-19, as well as the war in Ukraine, is covered. The variables selected for this study are RTSI, Eurostoxx, S&P 500, EUR/USD and RUB/USD exchange rates and crude oil prices. The selection of the specific variables was made because they are directly related to the pre-war period that coincides with the post-vaccine period of the pandemic, which allowed us to characterize it as the normal period and to characterize the period of the war in Ukraine that coincides with the energy crisis as the unstable period. In this way, the present study covers the markets of Russia and other developed economies. For empirical purposes, we applied a wavelet coherence approach in order to investigate the possible existence of simultaneous coherence between the variables at different times and scales for all the considered times. The findings of the study reveal the existence of strong correlations between all variables, during different time periods and for different frequencies during the period under review. Of particular interest is the finding that shows that during the crisis period, the RTSI significantly affects both the European and American stock markets, while also determining the evolution of the Russian currency. In addition, it appears that capital constraints in the Russian stock market, combined with increased demand for crude oil, determine the interdependence between RTSI and crude oil. Finally, an interesting finding of the study is the existence of a negative correlation between the US stock index and crude oil in low-frequency bands and the RTSI and Eurostoxx with crude oil for the post-vaccination and pre-war periods in the medium term. These findings can be used by both investors and portfolio managers to hedge risks and make more confident investment decisions. In addition, these findings can be used by policy makers in the planning of regulatory policies regarding the limitations of the systemic risks in capital markets.
Experimental Study of the Feasibility of In-Situ Hydrogen Generation from Gas Reservoir
Authors: Rui Yiming , Zhu Bin , Tang Qingsong , Yang Changcheng , Wang Dan , Pu Wanfen , Tang Xiaodong
Published: November 2022

Due to there is no better way to exploit depleted gas reservoirs, and hydrogen can generate from natural gas combustion. In this paper, the possibility of in-situ hydrogen generation in air injected gas reservoirs was determined through pseudo dynamic experiments. The study indicated that higher temperature and steam/methane ratio can generate more hydrogen, and the temperature should not be lower than 600 °C within gas reservoirs. The debris has positive catalysis for hydrogen generation. The maximum mole fraction of hydrogen was 26.63% at 600 °C.
Experimental Investigation of Flow-Induced Motion and Energy Conversion for Two Rigidly Coupled Triangular Prisms Arranged in Tandem
Authors: Lian Jijian , Wu Zhichuan , Yao Shuai , Yan Xiang , Wang Xiaoqun , Jia Zhaolin , Long Yan , Shao Nan , Yang Defeng , Li Xinyi
Published: November 2022

A series of experimental tests on flow-induced motion (FIM) and energy conversion of two rigidly coupled triangular prisms (TRCTP) in tandem arrangement were conducted in a recirculating water channel with the constant oscillation mass mosc. The incoming flow velocity covered the range of 0.395 m/s ≤ U ≤ 1.438 m/s, corresponding to the Reynolds number range of 3.45 × 104 ≤ Re ≤ 1.25 × 105. The upstream and downstream triangular prisms with a width of 0.1 m and length of 0.9 m were connected by two rectangular endplates. Seven stiffness (1000 N/m ≤ K ≤ 2400 N/m), five load resistances (8 Ω ≤ RL ≤ 23 Ω), and five gap ratios (1 ≤ L/D ≤ 4) were selected as the parameters, and the FIM responses and energy conversion of TRCTP in tandem were analyzed and discussed to illustrate the effects. The experimental results indicate that the “sharp jump” phenomenon may appear at L/D = 2 and L/D = 3 significantly, with substantially increasing amplitude and decreasing oscillation frequency. The maximum amplitude ratio in the experiments is A*Max = 2.24, which appears after the “sharp jump” phenomenon at L/D = 3. In the present tests, the optimal active power Pharn = 21.04 W appears at L/D = 4 (Ur = 12.25, K = 2000 N/m, RL = 8 Ω), corresponding to the energy conversion efficiency ηharn = 4.67%.
Thermal Performance in Convection Flow of Nanofluids Using a Deep Convolutional Neural Network
Authors: Hua Yue , Peng Jiang-Zhou , Zhou Zhi-Fu , Wu Wei-Tao , He Yong , Massoudi Mehrdad
Published: November 2022

This study develops a geometry adaptive, physical field predictor for the combined forced and natural convection flow of a nanofluid in horizontal single or double-inner cylinder annular pipes with various inner cylinder sizes and placements based on deep learning. The predictor is built with a convolutional-deconvolutional structure, where the input is the annulus cross-section geometry and the output is the temperature and the Nusselt number for the nanofluid-filled annulus. Profiting from the proven ability of dealing with pixel-like data, the convolutional neural network (CNN)-based predictor enables an accurate end-to-end mapping from the geometry input and the desired nanofluid physical field. Taking the computational fluid dynamics (CFD) calculation as the basis of our approach, the obtained results show that the average accuracy of the predicted temperature field and the coefficient of determination R2 are more than 99.9% and 0.998 accurate for single-inner cylinder nanofluid-filled annulus; while for the more complex case of double-inner cylinder, the results are still very close, higher than 99.8% and 0.99, respectively. Furthermore, the predictor takes only 0.038 s for each nanofluid field prediction, four orders of magnitude faster than the numerical simulation. The high accuracy and the fast speed estimation of the proposed predictor show the great potential of this approach to perform efficient inner cylinder configuration design and optimization for nanofluid-filled annulus.
Thermophilic Water Gas Shift Reaction at High Carbon Monoxide and Hydrogen Partial Pressures in Parageobacillus thermoglucosidasius KP1013
Authors: Díaz Daniel Barón , Neumann Anke , Aliyu Habibu
Published: November 2022

The facultatively anaerobic Parageobacillus thermoglucosidasius oxidizes carbon monoxide to produce hydrogen via the water gas shift (WGS) reaction. In the current work, we examined the influence of carbon monoxide (CO) and hydrogen (H2) on the WGS reaction in the thermophilic P. thermoglucosidasius by cultivating two hydrogenogenic strains under varying CO and H2 compositions. Microbial growth and dynamics of the WGS reaction were monitored by evaluating parameters such as pressure, headspace composition, metabolic intermediates, pH, and optical density. Our analyses revealed that compared to the previously studied P. thermoglucosidasius strains, the strain KP1013 demonstrated higher CO tolerance and improved WGS reaction kinetics. Under anaerobic conditions, the lag phase before the WGS reaction shortened to 8 h, with KP1013 showing no hydrogen-induced product inhibition at hydrogen partial pressures up to 1.25 bar. The observed lack of product inhibition and the reduced lag phase of the WGS reaction support the possibility of establishing an industrial process for biohydrogen production with P. thermoglucosidasius.
Corn Stover Pretreatment with Na2CO3 Solution from Absorption of Recovered CO2
Authors: García-Negrón Valerie , Toht Matthew J.
Published: November 2022

Renewable resources such as lignocellulosic biomass are effective at producing fermentable sugars during enzymatic hydrolysis when pretreated. Optimizing pretreatment methods for delignification while maintaining sustainability and low processing costs requires innovative strategies such as reusing greenhouse gas emissions for materials processing. Corn stover, an agricultural waste residue, was pretreated with 2.2 M Na2CO3 produced from CO2 captured via absorption in a 5 M NaOH solution. Composition analysis of the pretreated corn stover exhibited higher cellulose content (40.96%) and less lignin (16.50%) than the untreated biomass. Changes in the chemical structures are visible in the FTIR-ATR spectra, particularly in the cellulose and lignin-related absorption bands. The sugar release from hydrolysis was evaluated at different time intervals and by varying two enzyme ratios of CTec2-to-HTec2 (2:1 and 3:1). Enzymatic hydrolysis produced higher and more stable glucose yields for the pretreated biomass, surpassing 90% after 24 h using the 3:1 enzyme ratio. Sugar concentrations notably increased after pretreatment and even more when using the cellulase-rich enzyme solution. The maximum glucose, xylose, and arabinose recovered were 44, 19, and 2.3 g L−1. These results demonstrate the viability of capturing CO2 and converting it into an efficient Na2CO3 pretreatment for corn stover biomass. Additional processing optimizations depend on the combination of physicochemical parameters selected.
Astragalus membranaceus Extract (AME) Enhances Growth, Digestive Enzymes, Antioxidant Capacity, and Immunity of Pangasianodon hypophthalmus Juveniles
Authors: Abdel-Latif Hany M. R. , Ahmed Hamada A. , Shukry Mustafa , Chaklader Md Reaz , Saleh Rasha M. , Khallaf Mohamed A.
Published: November 2022

The present study evaluated the impacts of powdered Astragalus membranaceus extract (AME) on the growth, physiological responses, and serum immunity of Pangasianodon hypophthalmus juveniles. Four test diets were formulated to include varying AME levels as 0.0 (control), 1.5 (AME1.5), 3.0 (AME3.0), and 4.5 (AME4.5) g/kg. Fish weighing approximately 11.50 g were stocked into four triplicate groups and hand-fed on the test diets three times daily for two months. At 60 days post-feeding, the growth performance, including weight gain and the specific growth rate, was increased quadratically (R2 > 0.90) with increasing AME inclusion levels. An improvement in the feed intake and feed conversion ratio were also noticed in groups fed at different AME levels. The whole-body and amino acid composition were unaffected by the test diets. A significant quadratic trend in the digestive enzymes (lipase, α-amylase, and protease) was found along with increasing AME inclusion levels. Liver enzymes associated with liver functions were improved by AME dietary inclusion levels. Meanwhile, the blood urea nitrogen, uric acid, and creatinine values were unaffected by AME dietary inclusion. On the other hand, serum immunity (lysozyme and total Igs) was elevated with a significant quadratic trend along with increasing AME dietary inclusion levels. Liver MDA levels decreased with increasing AME levels. Liver CAT, GPx, and SOD enzyme activities demonstrated a significant increasing trend along with dietary AME inclusion. The aforementioned effects of dietary AME on P. hypophthalmus health underpinned the potentiality of AME to be used as a phyto-additive to improve the functionality of aquafeed.
Recent Research on Fusarium Mycotoxins in Maize—A Review
Authors: Bryła Marcin , Pierzgalski Adam , Zapaśnik Agnieszka , Uwineza Pascaline Aimee , Ksieniewicz-Woźniak Edyta , Modrzewska Marta , Waśkiewicz Agnieszka
Published: November 2022

Maize (Zea mays L.) is one of the most susceptible crops to pathogenic fungal infections, and in particular to the Fusarium species. Secondary metabolites of Fusarium spp.—mycotoxins are not only phytotoxic, but also harmful to humans and animals. They can cause acute or chronic diseases with various toxic effects. The European Union member states apply standards and legal regulations on the permissible levels of mycotoxins in food and feed. This review summarises the most recent knowledge on the occurrence of toxic secondary metabolites of Fusarium in maize, taking into account modified forms of mycotoxins, the progress in research related to the health effects of consuming food or feed contaminated with mycotoxins, and also the development of biological methods for limiting and/or eliminating the presence of the same in the food chain and in compound feed.