bluuebunny/crossref_metadata_2025 huggingface dataset:
Echocardiographic Evaluation of Right Ventricular (RV) Performance over Time in COVID-19-Associated ARDS—A Prospective Observational Study
Authors: Asgarpur Golschan , Treskatsch Sascha , Angermair Stefan , Danassis Michaela , Nothnagel Anna Maria , Toepper Christoph , Trauzeddel Ralf Felix , Nordine Michael , Heeschen Julia , Al-Chehadeh Alaa , Landmesser Ulf , Sander Leif Erik , Kurth Florian , Berger Christian
Published: May 2021

(1) Background: To evaluate time-dependent right ventricular (RV) performance in patients with COVID-19-associated acute respiratory distress syndrome (ARDS) undergoing intensive care (ICU) treatment. (2) Methods: This prospective observational study included 21 ICU patients with COVID-19-associated ARDS in a university hospital in 2020 (first wave). Patients were evaluated by transthoracic echocardiography at an early (EE) and late (LE) stage of disease. Echocardiographic parameters describing RV size and function as well as RV size in correlation to PaO2/FiO2 ratio were assessed in survivors and nonsurvivors. (3) Results: Echocardiographic RV parameters were within normal range and not significantly different between EE and LE. Comparing survivors and nonsurvivors revealed no differences in RV performance at EE. Linear regression analysis did not show a correlation between RV size and PaO2/FiO2 ratio over all measurements. Analysing EE and LE separately showed a significant increase in RV size correlated to a lower PaO2/FiO2 ratio at a later stage of COVID-19 ARDS. (4) Conclusion: The present study reveals neither a severe RV dilatation nor an impairment of systolic RV function during the initial course of COVID-19-associated ARDS. A trend towards an increase in RV size in correlation with ARDS severity in the second week after ICU admission was observed.
Wide Variation in Post-Void Residual Management after Urogynecologic Surgery: A Survey of Urogynecologists’ Practices
Authors: Marschalek Marie-Louise , Umek Wolfgang , Koelbl Heinz , Veit-Rubin Nikolaus , Bodner-Adler Barbara , Husslein Heinrich
Published: May 2021

To date there is no standardized regimen or evidence-based practical guideline concerning post-void residual (PVR) measurement after urogynecologic surgeries. This survey aimed to evaluate current practice patterns and the approach taken among urogynecologists surrounding PVR measurement. An online survey was sent to members of several urogynecologic societies assessing pre- and postoperative management of patients undergoing urogynecologic surgery. A total of 204 urogynecologists from 21 countries participated in the survey. The vast majority of urogynecologists perform some kind of voiding trial to assess voiding function postoperatively. The cut-off values to perform catheterization, the methods of measurement, and the number of successfully passed voiding showed strong differences. Only 34.4% of the respondents consider routine PVR measurement after urogynecologic surgery to be evidence-based. PVR measurement after urogynecologic surgeries is widely performed and if pathological, it almost always provokes invasive treatment. However, there is a wide variation of implemented strategies, methods, and cut-off values. Scientific societies are challenged to devise a standardized regimen based on evidence for the management of urinary retention after urogynecologic surgery.
The Influence of Multidrug-Resistant Bacteria on Clinical Outcomes of Diabetic Foot Ulcers: A Systematic Review
Authors: Matta-Gutiérrez Gianmarco , García-Morales Esther , García-Álvarez Yolanda , Álvaro-Afonso Francisco Javier , Molines-Barroso Raúl Juan , Lázaro-Martínez José Luis
Published: May 2021

Multidrug-resistant organism infections have become important in recent years due to the increased prevalence of diabetic foot ulcers and their possible consequences. This study aimed to systematically review and evaluate ulcer duration, healing time, hospital stay, amputation, and mortality rates in patients with diabetic foot ulcers caused by infection with multidrug-resistant organisms. PubMed, the Cochrane Library, and Web of Science were searched in May 2020 to find observational studies in English about the clinical outcomes of multidrug-resistant organism infection in diabetic foot ulcers. Eight studies met the inclusion criteria, and these studies included 923 patients. The overall methodological quality of the study was moderate. Ulcer duration was described in six studies, and there was no practical association with multidrug-resistant organisms. Two out of three studies reported a longer healing time in multidrug-resistant organism infections than in non-multidrug-resistant organism infections. Clinical outcomes included the duration of hospitalisation, surgeries, amputations, and deaths. Lower limb amputation was the most reported clinical outcome in the included studies, and was more prevalent in the multidrug-resistant organism infections. We concluded that there was not enough evidence that multidrug-resistant organisms hindered the healing of diabetic foot ulcers. In contrast to the clinical outcomes, multidrug-resistant organisms affect both amputation rates and mortality rates.
Epidemiology and the Impact of Acute Kidney Injury on Outcomes in Patients with Rhabdomyolysis
Authors: Yang Chien-Wen , Li Si , Dong Yishan , Paliwal Nitpriya , Wang Yichen
Published: May 2021

Background: Currently, no large, nationwide studies have been conducted to analyze the demographic factors, underlying comorbidities, clinical outcomes, and health care utilization in rhabdomyolysis patients with and without acute kidney injury (AKI). Methods: We queried the National Inpatient Sample of Healthcare Cost and Utilization Project (HCUP) with patients with rhabdomyolysis from 2016 to 2018. The chi-squared test was used to compare categorical variables, and the adjusted Wald test was employed to compare quantitative variables. The logistic regression model was applied to calculate adjusted odds ratios (ORs) with 95% confidence intervals (95% CIs) to estimate the impact of AKI on outcomes in patients with rhabdomyolysis. Results: Among 111,085 rhabdomyolysis-related hospitalizations, a higher prevalence of AKI was noticed in older patients (mean age ± SD, 58.2 ± 21.6 vs. 53.8 ± 22.2), Medicare insurance (48.5% vs. 43.2%), and patients with a higher Charlson Comorbidity Index score (CCI 3–5, 15.1% vs. 5.5%). AKI was found to be independently associated with higher mortality (adjusted odds ratio [aOR] 3.33, 95% CI 2.33–4.75), longer hospital stays (adjusted difference 1.17 days, 95% CI: 1.00−1.34), and higher cost of hospital stay (adjusted difference $11,315.05, 95% CI: $9493.02–$13,137.07). Conclusions: AKI in patients hospitalized with rhabdomyolysis is related to adverse clinical outcomes and significant economic and survival burden.
Risk Factors for Mortality in COVID-19 Hospitalized Patients in Piedmont, Italy: Results from the Multicenter, Regional, CORACLE Registry
Authors: De Rosa Francesco Giuseppe , Palazzo Annagloria , Rosso Tiziana , Shbaklo Nour , Mussa Marco , Boglione Lucio , Borgogno Enrica , Rossati Antonella , Mornese Pinna Simone , Scabini Silvia , Chichino Guido , Borrè Silvio , Del Bono Valerio , Garavelli Pietro Luigi , Barillà Diego , Cattel Francesco , Di Perri Giovanni , Ciccone Giovannino , Lupia Tommaso , Corcione Silvia
Published: May 2021

Background: CORACLE is a retrospective and prospective, regional multicenter registry, developed to evaluate risk factors for mortality in a cohort of patients admitted with SARS-CoV-2 infection within non-intensive wards. Methods: The primary objective was to estimate the role of several prognostic factors on hospital mortality in terms of adjusted Odds Ratios (aOR) with multivariable logistic regression models. Results: A total of 1538 patients were enrolled; 42% were female, and 58% were >70 years old. Deceased patients were 422 (27%), with a median age of 83 years (IQR (Inter Quartile Range) 76–87). Older age at admission (aOR 1.07 per year, 95%CI 1.06–1.09), diabetes (1.41, 1.02–1.94), cardiovascular disease (1.79, 1.31–2.44), immunosuppression (1.65, 1.04–2.62), estimated glomerular filtration rate (eGFR) <30 mL/min/1.73 m2 (3.53, 2.26–5.51), higher C-reactive protein values and a decreased PaO2/FiO2 ratio at admission were associated with a higher risk of hospital mortality. Amongst patients still alive on day 7, only hydroxychloroquine (HCQ) treatment was associated with reduced mortality (0.57, 0.36–0.90). Conclusions: Several risk factors were associated with mortality in SARS-CoV-2 positive patients. Although HCQ seems to be the only factor significantly associated with reduced mortality, this result is in contrast with evidence from randomized studies. These results should be interpreted in light of the study limitations.
Hypertrophic Cardiomyopathy and Primary Restrictive Cardiomyopathy: Similarities, Differences and Phenocopies
Authors: Vio Riccardo , Angelini Annalisa , Basso Cristina , Cipriani Alberto , Zorzi Alessandro , Melacini Paola , Thiene Gaetano , Rampazzo Alessandra , Corrado Domenico , Calore Chiara
Published: May 2021

Hypertrophic cardiomyopathy (HCM) and primary restrictive cardiomyopathy (RCM) have a similar genetic background as they are both caused mainly by variants in sarcomeric genes. These “sarcomeric cardiomyopathies” also share diastolic dysfunction as the prevalent pathophysiological mechanism. Starting from the observation that patients with HCM and primary RCM may coexist in the same family, a characteristic pathophysiological profile of HCM with restrictive physiology has been recently described and supports the hypothesis that familiar forms of primary RCM may represent a part of the phenotypic spectrum of HCM rather than a different genetic cardiomyopathy. To further complicate this scenario some infiltrative (amyloidosis) and storage diseases (Fabry disease and glycogen storage diseases) may show either a hypertrophic or restrictive phenotype according to left ventricular wall thickness and filling pattern. Establishing a correct etiological diagnosis among HCM, primary RCM, and hypertrophic or restrictive phenocopies is of paramount importance for cascade family screening and therapy.
Systemic Lupus Erythematosus and Periodontal Disease: A Complex Clinical and Biological Interplay
Authors: Sojod Bouchra , Pidorodeski Nagano Cibele , Garcia Lopez Glenda Melissa , Zalcberg Antoine , Dridi Sophie Myriam , Anagnostou Fani
Published: May 2021

Reports on the association of periodontal disease (PD) with systemic lupus erythematosus (SLE) have regularly been published. PD is a set of chronic inflammatory conditions linked to a dysbiotic microbial biofilm, which affects the periodontal tissues, resulting eventually in their destruction and contributing to systemic inflammation. SLE is a multi-system chronic inflammatory autoimmune disease that has a wide range of clinical presentations, touching multiple organ systems. Many epidemiological studies have investigated the two-way relationship between PD and SLE, though their results are heterogeneous. SLE and PD are multifactorial conditions and many biological-based hypotheses suggest common physiopathological pathways between the two diseases, including genetics, microbiology, immunity, and environmental common risk factors. By focusing on recent clinical and translational research, this review aimed to discuss and give an overview of the relationship of SLE with PD, as well as looking at the similarities in the immune-pathological aspects and the possible mechanisms connecting the development and progression of both diseases.
Individual Characteristics as Prognostic Factors of the Evolution of Hospitalized COVID-19 Romanian Patients: A Comparative Observational Study between the First and Second Waves Based on Gaussian Graphical Models and Structural Equation Modeling
Authors: Mocanu Alexandra , Noja Gratiela Georgiana , Istodor Alin Viorel , Moise Georgiana , Leretter Marius , Rusu Laura-Cristina , Marza Adina Maria , Mederle Alexandru Ovidiu
Published: May 2021

This study examines the role played by individual characteristics and specific treatment methods in the evolution of hospitalized patients with coronavirus disease 2019 (COVID-19), through the lens of an observational study performed in a comparative approach between the first and second waves of coronavirus pandemic in Romania. The research endeavor is configured on a two-fold approach, including a detailed observation of the evolution of 274 hospitalized patients with COVID-19 (145 in the first wave and 129 in the second wave of infection) according to specific treatment methods applied and patients’ individual features, as well as an econometric (quantitative) analysis through structural equation modeling and Gaussian graphical models designed to acknowledge the correlations and causal relationship between all considered coordinates. The main results highlight that the specific treatment methods applied had a positive influence on the evolution of COVID-19 patients, particularly in the second wave of coronavirus pandemic. In case of the first wave of COVID-19 infection, GGM results entail that there is a strong positive correlation between the evolution of the patients and the COVID-19 disease form, which is further positively correlated with the treatment scheme. The evolution of the patients is strongly and inversely correlated with the symptomatology and the ICU hospitalization. Moreover, the disease form is strongly and inversely correlated with oxygen saturation and the residence of patients (urban/rural). The symptomatology at first appearance also strongly depends on the age of the patients (positive correlation) and of the fact that the patient is a smoker or non-smoker and has other comorbidities. Age and gender are also important credentials that shape the disease degree and patient evolution in responding to treatment as well, our study attesting strong interconnections between these coordinates, the form of disease, symptomatology and overall evolution of the patients.
A State-of-the-Art Survey on Artificial Intelligence to Fight COVID-19
Authors: Islam Md. Mohaimenul , Poly Tahmina Nasrin , Alsinglawi Belal , Lin Ming Chin , Hsu Min-Huei , Li Yu-Chuan (Jack)
Published: May 2021

Artificial intelligence (AI) has shown immense potential to fight COVID-19 in many ways. This paper focuses primarily on AI’s role in managing COVID-19 using digital images, clinical and laboratory data analysis, and a summary of the most recent articles published last year. We surveyed the use of AI for COVID-19 detection, screening, diagnosis, the progression of severity, mortality, drug repurposing, and other tasks. We started with the technical overview of all models used to fight the COVID-19 pandemic and ended with a brief statement of the current state-of-the-art, limitations, and challenges.
Comparison of Two Commercial Colorimetric Broth Microdilution Tests for Candida Susceptibility Testing: Sensititre YeastOne versus MICRONAUT-AM
Authors: Philips Sophie , Van Hoecke Frederik , De Laere Emmanuel , Vervaeke Steven , De Smedt Roos , Boelens Jerina , De Geyter Deborah , Piérard Denis , Lagrou Katrien
Published: May 2021

Two colorimetric broth microdilution antifungal susceptibility tests were compared, Sensititre YeastOne and MICRONAUT-AM for nine antifungal agents. One hundred clinical Candida isolates were tested, representing a realistic population for susceptibility testing in daily practice. The reproducibility characteristics were comparable. Only for fluconazole, caspofungin, 5-flucytosine and amphotericin B, an essential agreement of ≥90% could be demonstrated. Sensititre minimal inhibitory concentrations (MICs) were systematically higher than MICRONAUT MICs for all antifungals, except for itraconazole. CLSI clinical breakpoints (CBPs) and epidemiological cut-off values (ECVs) were used for Sensititre MICs while for MICRONAUT the EUCAST CBPs and ECVs were used. Only fluconazole, micafungin, and amphotericin B had a categorical agreement of ≥90%. For fluconazole, micafungin, and amphotericin B the susceptibility proportions were comparable. Susceptibility proportion of posaconazole and voriconazole was higher using the MICRONAUT system. For itraconazole and anidulafungin, the susceptibility proportion was higher using Sensititre. It was not possible to determine the true MIC values or the correctness of a S/I/R result since both commercial systems were validated against a different reference method. These findings show that there is a significant variability in susceptibility pattern and consequently on use of antifungals in daily practice, depending on the choice of commercial system.
Daldiniaeschsone A, a Rare Tricyclic Polyketide Having a Chromone Unit Fused to a δ-Lactone and Its Symmetrical Biphenyl Dimer, Daldiniaeschsone B, from an Endophytic Fungus Daldinia eschscholtzii SDBR-CMUNKC745
Authors: Wutthiwong Natnicha , Suthiphasilp Virayu , Pintatum Aknarin , Suwannarach Nakarin , Kumla Jaturong , Lumyong Saisamorn , Maneerat Tharakorn , Charoensup Rawiwan , Cheenpracha Sarot , Limtharakul Thunwadee , Pyne Stephen G. , Laphookhieo Surat
Published: May 2021

Daldiniaeschsone A (1), a rare tricyclic polyketide having a chromone unit fused to a δ-lactone and its symmetrical 6,6′-biphenyl dimer, daldiniaeschsone B (2), together with three known compounds (3−5), were isolated from a plant-derived endophytic fungus, Daldinia eschscholtzii SDBR-CMUNKC745. Their structures were elucidated by extensive 1D and 2D NMR spectroscopic data and HRESIMS. All compounds showed α-glucosidase inhibitory activity with IC50 values ranging from 0.16−0.85 mM and compound 1 was the best α-glucosidase inhibitory activity (IC50 = 0.16 mM).
Robust and Accurate Mandible Segmentation on Dental CBCT Scans Affected by Metal Artifacts Using a Prior Shape Model
Authors: Qiu Bingjiang , van der Wel Hylke , Kraeima Joep , Hendrik Glas Haye , Guo Jiapan , Borra Ronald J. H. , Witjes Max Johannes Hendrikus , van Ooijen Peter M. A.
Published: May 2021

Accurate mandible segmentation is significant in the field of maxillofacial surgery to guide clinical diagnosis and treatment and develop appropriate surgical plans. In particular, cone-beam computed tomography (CBCT) images with metal parts, such as those used in oral and maxillofacial surgery (OMFS), often have susceptibilities when metal artifacts are present such as weak and blurred boundaries caused by a high-attenuation material and a low radiation dose in image acquisition. To overcome this problem, this paper proposes a novel deep learning-based approach (SASeg) for automated mandible segmentation that perceives overall mandible anatomical knowledge. SASeg utilizes a prior shape feature extractor (PSFE) module based on a mean mandible shape, and recurrent connections maintain the continuity structure of the mandible. The effectiveness of the proposed network is substantiated on a dental CBCT dataset from orthodontic treatment containing 59 patients. The experiments show that the proposed SASeg can be easily used to improve the prediction accuracy in a dental CBCT dataset corrupted by metal artifacts. In addition, the experimental results on the PDDCA dataset demonstrate that, compared with the state-of-the-art mandible segmentation models, our proposed SASeg can achieve better segmentation performance.
Parathyroid Hormone Gene and Genes Involved in the Maintenance of Vitamin D Levels Association with Mandibular Retrognathism
Authors: Küchler Erika , Reis Caio , Marañón-Vásquez Guido , Nelson-Filho Paulo , Matsumoto Mírian , Stuani Maria , Oliveira Maria , Proff Peter , Kirschneck Christian
Published: May 2021

In this study we evaluated whether single nucleotide polymorphisms (SNPs) in the genes encoding PTH, VDR, CYP24A1, and CYP27B1 were associated with mandibular retrognathism (MR). Samples from biologically-unrelated Brazilian patients receiving orthodontic treatment were included in this study. Pre-orthodontic lateral cephalograms were used to determine the phenotype. Patients with a retrognathic mandible were selected as cases and those with an orthognathic mandible were selected as controls. Genomic DNA was used for genotyping analysis of SNPs in PTH (rs694, rs6256, and rs307247), VDR (rs7975232), CYP24A1 (rs464653), and CYP27B1 (rs927650). Chi-squared or Fisher’s tests were used to compare genotype and allele distribution among groups. Haplotype analysis was performed for the SNPs in PTH. The established alpha was p < 0.05. Multifactor dimensionality reduction (MDR) was used to identify SNP–SNP interactions. A total of 48 (22 males and 26 females) MR and 43 (17 males and 26 females) controls were included. The linear mandibular and the angular measurements were statistically different between MR and controls (p < 0.05). In the genotype and allele distribution analysis, the SNPs rs694, rs307247, and rs464653 were associated with MR (p < 0.05). MDR analyses predicted the best interaction model for MR was rs694–rs927650, followed by rs307247–rs464653–rs927650. Some haplotypes in the PTH gene presented statistical significance. Our results suggest that SNPs in PTH, VDR, CYP24A1, and CYP27B1 genes are associated with the presence of mandibular retrognathism.
Predicting Firms’ Financial Distress: An Empirical Analysis Using the F-Score Model
Authors: Rahman Mahfuzur , Sa Cheong Li , Masud Md. Abdul Kaium
Published: May 2021

Financial performance of firms is very important to bankers, shareholders, potential investors, and creditors. The inability of firms to meet their liabilities will affect all its stakeholders and will result in negative consequences in the wider economy. The objective of the study is to explore the applicability of a distress prediction model which uses the F-Score and its components to identify firms which are at high risk of going into default. The study incorporates a prediction model and vast literature to address the research questions. The sample of the study is collected from publicly listed firms of the United States. In total, 81 financially distressed firms wereextracted from the UCLA-LoPucki Bankruptcy Research Database during 2009–2017. This study found that the relationship of the F-Score and probability of firms going into financial distress is significant. This study also demonstrated that firms which are at risk of distress tend to record a negative cash flow from operations (CFO) and showed a greater decline in return on assets (ROA) in the year prior to default. This study extends the existing literature by supporting a model which has not been widely used in the area of financial distress predictions.
Spillovers of the COVID-19 Pandemic: Impact on Global Economic Activity, the Stock Market, and the Energy Sector
Authors: Hasan Md. Bokhtiar , Mahi Masnun , Sarker Tapan , Amin Md. Ruhul
Published: May 2021

In this study, we examine the effect of the COVID-19 pandemic on global economic activity, the stock market, and the energy sector considering the sizable damaging impacts in these crucial aspects. Our results, based on the structural vector autoregression (SVAR) model for the data from 21 January 2020, to 26 February 2021, indicate that the COVID-19 cases significantly and negatively impact all the endogenous variables such as Baltic dry index (BDI), MSCI world index (MSCI), and MSCI world energy index (MSCIE). Our results also reveal that of the three variables, the stock markets indices (MSCI and MSCIE) are comparatively more affected by COVID-19 cases. The findings imply that the stock markets are more sensitive to the COVID-19 pandemic than the real economy. The results further indicate that of the three variables, the MSCIE index is the most affected by COVID-19 due to two factors: one is the dwindling power consumption caused by COVID-19 and the other is the decline in oil price because of the Russia–OPEC price war. Our findings enhance the understanding of the spillover impacts of the global health crisis on economic activity, the stock market, and the energy sector. Moreover, our study offers insights for policymakers and governments into the relationship dynamics of COVID-19 that would help them be more cautious in taking preventive measures against the health crisis to save the economy, the stock market, and the energy sector from falling into a more deepened crisis.
Changes in Woody Vegetation over 31 Years in Farmed Parkland of the Central Plateau, Burkina Faso
Authors: Takenaka Koichi , Ikazaki Kenta , Simporé Saïdou , Kaboré François , Thiombiano Natacha , Koala Jonas
Published: May 2021

Farmed parklands of the Central Plateau, Burkina Faso, integrate native woody vegetation with managed cropland. However, sapling survival in the parklands is increasingly threatened. This study characterized woody vegetation abundance along a 2.7 km long transect in the Doulou Basin, Boulkiemdé Province, Central West Region, to assess changes in vegetation composition since 1984. In addition, a householder survey was conducted to gain insight into tree uses and preferences and residents’ knowledge of regulations. In total, 4999 individuals from 26 tree species were recorded, including 123 individuals (11 species) with stem DBH ≥ 5 cm, and 4876 individuals (21 species) with stem DBH < 5 cm. The three species with the highest importance value index provided fruit for sale or self-consumption. Tree abundance was associated with soil type and topography; highest abundance was on Lixisol soils along the lower transect. Soil degradation and preference changes among residents since 1984 may have influenced tree abundance. Certain beneficial species (e.g., Vitellaria paradoxa) have declined in abundance, and certain exotics (Azadirachta indica and Eucalyptus camaldulensis) have expanded in distribution. Respondents expressed strongest interest in three species, including V. paradoxa, that show high versatility. These results supported the recorded tree composition. The respondents generally understood forest conservation regulations. Dissemination of regreening technology and awareness promotion among residents is essential for sustainable tree use in farmed parklands.
Measuring Dynamic Changes in the Spatial Pattern and Connectivity of Surface Waters Based on Landscape and Graph Metrics: A Case Study of Henan Province in Central China
Authors: Mu Bo , Tian Guohang , Xin Gengyu , Hu Miao , Yang Panpan , Wang Yiwen , Xie Hao , Mayer Audrey L. , Zhang Yali
Published: May 2021

An understanding of the scientific layout of surface water space is crucial for the sustainable development of human society and the ecological environment. The objective of this study was to use land-use/land-cover data to identify the spatiotemporal dynamic change processes and the influencing factors over the past three decades in Henan Province, central China. Multidisciplinary theories (landscape ecology and graph theory) and methods (GIS spatial analysis and SPSS correlation analysis) were used to quantify the dynamic changes in surface water pattern and connectivity. Our results revealed that the water area decreased significantly during the periods of 1990–2000 and 2010–2018 due to a decrease in tidal flats and linear waters, but increased significantly in 2000–2010 due to an increase in patchy waters. Human construction activities, socioeconomic development and topography were the key factors driving the dynamics of water pattern and connectivity. The use of graph metrics (node degree, betweenness centrality, and delta probability of connectivity) in combination with landscape metrics (Euclidean nearest-neighbor distance) can help establish the parameters of threshold distance between connected habitats, identify hubs and stepping stones, and determine the relatively important water patches that require priority protection or development.
Large-Scale Soil Erosion Estimation Considering Vegetation Growth Cycle
Authors: Zhuang Hanchen , Wang Yixin , Liu Hang , Wang Sijia , Zhang Wanqiu , Zhang Shuliang , Dai Qiang
Published: May 2021

The Revised Universal Soil Loss Equation (RUSLE) was used to predict the potential soil erosion; it simply multiplies rainfall erosivity and land cover management factors; it does not consider the dynamics of these two factors during a given year or the effect of vegetation growth cycle on soil erosion estimates. This study developed a new method that considers the vegetation growth cycle in different periods of the year by matching monthly rainfall erosivity and a management factor using the entire surface of China as the study area. The data were input into the original equation, and the two methods to estimate soil erosion were compared. Finally, patterns and mechanisms of the influence of vegetation growth cycle on RUSLE estimations under different climatic conditions were obtained. The results show that vegetation coverage inhibits the effect of rainfall on soil erosion potential, which is related to the average and coefficient of variation of cover-management factor and the average of rainfall erosivity due to the significant variations in weather patterns in winter and summer in China. This article discusses the influence of the vegetation growth cycle on the estimation of large-scale soil erosion, which is a key to having a better estimation.
Tribocorrosion Evaluation of Nb2O5, TiO2, and Nb2O5 + TiO2 Coatings for Medical Applications
Authors: Orozco-Hernández Giovany , Durán Pablo Guzmán , Aperador William
Published: May 2021

Materials used in biomedicine for purposes of long-time stay inside the body presents diverse sort of problems like cytotoxicity, wear, biocompatibility, and ion liberation along time. This paper presents the characterization of corrosion-wear combined phenomena on Nb2O5, TiO2, and Nb2O5 + TiO2 coatings with future applications as biomaterials. After the films’ production process using magnetron sputtering technique, they were characterized through an optic, scanning electron, and atomic force microscopy to evaluate their morphology, structure, and surface damage suffered by the synergy between wear and corrosion phenomena. The life in service of the implant was evaluated in terms of the coating behavior against inside body conditions like charge, wear, and electrochemical degradation. This test was made with electrochemical measurements in simulated biological fluid combined with the wear characterization implementing a potentiostat and a tribometer in a linear wear configuration with a bone pin. As a result, the different electrochemical responses of the films were evidenced by polarization curves and equivalent circuits of the systems. The coefficient of friction and surface degradation were also obtained and evaluated. Comparing the properties of the systems, we conclude that TiO2 coatings have better behavior in terms of the wear-corrosion synergy phenomena while the systems with Nb present pitting corrosion.
N,N-bis(2-quinolinylmethyl)benzylamine
Authors: Hunter Leigh A. , Naidoo Shivani , Mambanda Allen
Published: May 2021

N,N-bis(2-quinolinylmethyl)benzylamine (1) was synthesized under basic conditions from a pseudo-three-component reaction between benzylamine and two molecules of 2-(quinolinylmethyl)chloride, resulting in the formation of two N–C bonds in a single step. Compound (1) crystallizes in the triclinic system of the P-1 space group. The unit cell comprises a dimer of 1, in which the monomers are linked by two complementary hydrogen bonds between N1 and H′1–C′1 of another molecule. The dimers form chains along the a-axis through intermolecular interactions between the N′2 acceptor atoms and C″17 donors from molecules in the nearest neighboring dimer. These interactions form extended sheets of the dimers of 1, along the ab plane. The quinolinylmeth-2-yl groups of 1 lie in almost orthogonal planes and their N1/2(q) donor atoms are away from the apical amino N3 atom.
Advanced Photonic Thin Films for Solar Irradiation Tuneability Oriented to Greenhouse Applications
Authors: Sánchez-Lanuza M. Barragán , Menéndez-Velázquez Amador , Peñas-Sanjuan Antonio , Navas-Martos Francisco J. , Lillo-Bravo Isidoro , Delgado-Sánchez José-María
Published: May 2021

The world population is growing by 1 billion people every 10 years. There will come a time when there will be more people to feed but less land to grow food. Greenhouses can be the solution to this problem because they provide the highest production yield per m2 and also use less water, provide food safety, and offer high quality. Photosynthetic active radiation (PAR) favors vegetable growth with a specific blue and red light ratio. Thus, increasing the amount of red light improves chlorophyll absorption and photosynthetic efficiency. In this article, we present a hybrid system that combines luminescent materials and photonic crystals for better management of the light reaching the greenhouse. The luminescent dyes considered herein are combined ensuring a Förster resonance energy transfer (FRET) nonradiative mechanism to enhance the absorption range. The designed photonic crystal maximizes reflections in the Near-Infrared (NIR) range, and therefore, thermal losses are minimized. Thus, by converting harmful or ineffective radiation for plant growth to the PAR region, we aim to demonstrate growth-condition enhancement for the different vegetables that have been used as a model.
Low Cycle Fatigue Life Assessment Based on the Accumulated Plastic Strain Energy Density
Authors: Hu Yifeng , Shi Junping , Cao Xiaoshan , Zhi Jinju
Published: May 2021

The accumulated plastic strain energy density at a dangerous point is studied to estimate the low cycle fatigue life that is composed of fatigue initiation life and fatigue crack propagation life. The modified Ramberg–Osgood constitutive relation is applied to characterize the stress–strain relationship of the strain-hardening material. The plastic strain energy density under uni-axial tension and cyclic load are derived, which are used as threshold and reference values, respectively. Then, a framework to assess the lives of fatigue initiation and fatigue crack propagation by accumulated plastic strain energy density is proposed. Finally, this method is applied to two types of aluminum alloy, LC9 and LY12 for low-cycle fatigue, and agreed well with the experiments.
Incremental Minimum Flow Algorithms
Authors: Ciupala Laura , Deaconu Adrian
Published: May 2021

There are various situations in which real-world problems can be modeled and solved as minimum flow problems. Sometimes, in these situations, minor data changes may occur, leading to corresponding changes of the networks in which the practical problems are modeled as flow problems, such as slight variations in capacity or lower bound. For instance, the capacity or the lower bound of an arc may increase or decrease in time, leaving one with no other choice than finding the new minimum network flow. Given both the various ways in which the networks can be changed and the high frequency of these changes, it is desirable to find as fast a computation method for minimum flow as possible. This paper is focused on the cases that concern increasing and decreasing the capacity or the lower bound of an arc. For these cases, both the minimum flow algorithms and the dynamic minimum flow algorithms that are already known are inefficient. Our incremental algorithms for determining minimum flow in the modified network are more efficient than both the above-mentioned types of algorithms. The proposed method starts from the initial network minimum flow and solves the minimum flow problem in a significantly faster way than recalculating the new network minimum flow starting from scratch.
A Markov-Switching VSTOXX Trading Algorithm for Enhancing EUR Stock Portfolio Performance
Authors: De la Torre-Torres Oscar V. , Galeana-Figueroa Evaristo , Álvarez-García José
Published: May 2021

In the present paper, we test the benefit of using Markov-Switching models and volatility futures diversification in a Euro-based stock portfolio. With weekly data of the Eurostoxx 50 (ESTOXX50) stock index, we forecasted the smoothed regime-specific probabilities at T + 1 and used them as the weighting method of a diversified portfolio in ESTOXX50 and ESTOSS50 volatility index (VSTOXX) futures. With the estimated smoothed probabilities from 9 July 2009 to 29 September 2020, we simulated the performance of three theoretical investors who paid different trading costs and invested in ESTOXX50 during calm periods (low volatility regime) or VSTOXX futures and the three-month German treasury bills in distressed or highly distressed periods (high and extreme volatility regimes). Our results suggest that diversification benefits hold in the short-term, but if a given investor manages a two-asset portfolio with ESTOXX50 and our simulated portfolios, the stock portfolio’s performance is enhanced significantly, in the long term, with the presence of trading costs. These results are of use to practitioners for algorithmic and active trading applications in ESTOXX50 ETFs and VSTOXX futures.
Dynamical Strategy to Control the Accuracy of the Nonlinear Bio-Mathematical Model of Malaria Infection
Authors: Noeiaghdam Samad , Micula Sanda
Published: May 2021

This study focuses on solving the nonlinear bio-mathematical model of malaria infection. For this aim, the HATM is applied since it performs better than other methods. The convergence theorem is proven to show the capabilities of this method. Instead of applying the FPA, the CESTAC method and the CADNA library are used, which are based on the DSA. Applying this method, we will be able to control the accuracy of the results obtained from the HATM. Also the optimal results and the numerical instabilities of the HATM can be obtained. In the CESTAC method, instead of applying the traditional absolute error to show the accuracy, we use a novel condition and the CESTAC main theorem allows us to do that. Plotting several ℏ-curves the regions of convergence are demonstrated. The numerical approximations are obtained based on both arithmetics.
Intraocular Pressure Reduction after Femtolaser Assisted Cataract Surgery and Its Association with the Use of Ultrasound
Authors: Abouzeid Hana , Ferrini Walter , Bochud Murielle
Published: May 2021

Background and Objectives: To quantify the change in intraocular pressure (IOP) after phacoemulsification in patients having undergone femtolaser assisted cataract surgery (FLACS), and study the influence of the use of ultrasound on this change. Setting: Jules-Gonin Eye Hospital, University Department of Ophthalmology, Lausanne, Switzerland. Materials and Methods: Interventional study. Methods: All consecutive cases operated with FLACS and with complete data for the studied parameters were selected for inclusion in the study. Data had been prospectively collected and was analysed retrospectively. Linear regression was performed to explore the association of change in IOP with time of measure, ultrasound use, sex, age, and duration of surgery. Results: There was a mean decrease in intraocular pressure of 2.5 mmHg (CI 95% −3.6; −1.4, p < 0.001) postoperatively. No association between the change in intraocular pressure and ultrasound time or effective phaco time was observed when the data were analyzed one at a time or in a multiple linear regression model. There was no association with sex, age, nuclear density, presence of pseudoexfoliation, duration of surgery, and time of ocular pressure measurement. Eyes with preoperative IOP ≥ 21 mmHg had a more significant IOP reduction after surgery (p < 0.0001) as did eyes with an anterior chamber depth <2.5 mm (p = 0.01). Conclusion: There was a decrease in intraocular pressure six months after FLACS in our study similar to that in the published literature for standard phacoemulsification. The use of ultrasound may not influence the size of the decrease, whereas the preoperative IOP and anterior chamber depth do. FLACS may be as valuable as standard phacoemulsification for cases where IOP reduction is needed postoperatively.
Towards Understanding Relationships between Tension Property and Twinning Boundaries in Magnesium Alloy
Authors: Bai Jianhui , Yang Pengfei , Yang Zhiyuan , Sun Qi , Tan Li
Published: May 2021

Although pre-induced {10 12¯} twins could strengthen magnesium and its alloys, the origin of such a strengthening phenomenon remains questionable. This is because twins can simultaneously change the size of grains and the texture features of the initial material. In the present work, the effect of pre-induced {101¯2} twins on the tension property of an extruded magnesium alloy has been investigated through a combination of electron backscatter diffraction, transmission electron microscope, and mechanical tests. Samples with and without {101¯2} twinning boundaries, but possessing an almost identical texture characteristic, were prepared by pre-compression perpendicular to the extrusion direction. Subsequently, these pre-strained samples were tensioned along the extrusion direction. The results indicate that the pre-induced {101¯2} twinning boundaries can indeed enhance the tension strength of magnesium alloys, but only slightly. The effect is closely associated with the amount of pre-strain. Correspondingly, the possible mechanisms behind such phenomena are given and discussed.
Laser Processing of Ni-Based Superalloy Surfaces Susceptible to Stress Concentration
Authors: Rajčić Boris , Petronić Sanja , Čolić Katarina , Stević Zoran , Petrović Ana , Mišković Žarko , Milovanović Dubravka
Published: May 2021

Reliable and resilient constructions are basic for ensuring the safety of various structures. The superalloys are used as constructive materials due to their superb mechanical properties and endurance. However, even these materials can have certain areas where the stress concentration is higher than expected, such as drilling holes, which are common in various structures that need additional enhancement. Surface laser modifications of the areas surrounding the holes drilled in Nimonic 263 sheets are done by pulsed picosecond and nanosecond Nd:YAG laser irradiations with pulse durations of 170 ps and ≤8 ns, respectively. Following the laser surface treatment, the effectiveness of the enhancement was analyzed by the microhardness test and the deformation test. The results show that the deformation and stress values are decreased by 25−40 percent, showing the improvement in the resilience to deformation. The Vickers microhardness test results indicate an improvement in the Nimonic 263 microhardness. The dimensions of the microcracks are higher for the untreated material in comparison to the laser-treated material.
Effect of Corrosion Time on the Synergistic Corrosion of Q235 Steel in Sodium Aluminate Solutions
Authors: Quan Bianli , Li Junqi , Chen Chaoyi
Published: May 2021

During Bayer alumina production with high-sulfur bauxite, the sulfide ions in the sodium aluminate solution caused serious corrosion to Q235 steel, which is the material of the tank equipment. This study investigates the effect of corrosion time on Q235 steel synergistic corrosion in sodium aluminate solution using the weight-loss method and electrochemical measurements. The results indicate that the corrosion rate decreases sharply, the rate equation satisfies the mathematical model of power function at the initial stage of corrosion, and the transformation of unstable iron sulfide to stable iron oxide at the later stage results in the decrease in sulfur content in the corrosion products and surface pseudo-passivation. There are two main types of corrosion products, as follows: one is the octahedral crystal particle, which is composed of Fe2O3, Fe3O4, Al2O3 and NaFeO2, and the other is the interlayer corrosion between the surface layer and the matrix, which is composed of FeS, FeS2 and MnS2. At day 3, the dynamics of the Q235 steel electrode is controlled by charge transfer and ion diffusion. However, at other times the dynamics are mainly controlled by charge transfer.
The Regulation of Non-Specific Membrane Permeability Transition in Yeast Mitochondria under Oxidative Stress
Authors: Isakova Elena P. , Klein Olga I. , Deryabina Yulia I.
Published: May 2021

In this study, the mechanism of non-specific membrane permeability (yPTP) in the Endomyces magnusii yeast mitochondria under oxidative stress due to blocking the key antioxidant enzymes has been investigated. We used monitoring the membrane potential at the cellular (potential-dependent staining) and mitochondrial levels and mitochondria ultra-structural images with transmission electron microscopy (TEM) to demonstrate the mitochondrial permeability transition induction due to the pore opening. Analysis of the yPTP opening upon respiring different substrates showed that NAD(P)H completely blocked the development of the yPTP. The yPTP opening was inhibited by 5–20 mM Pi, 5 mM Mg2+, adenine nucleotides (AN), 5 mM GSH, the inhibitor of the Pi transporter (PiC), 100 μM mersalyl, the blockers of the adenine nucleotide transporter (ANT) carboxyatractyloside (CATR), and bongkrekic acid (BA). We concluded that the non-specific membrane permeability pore opens in the E. magnusii mitochondria under oxidative stress, and the ANT and PiC are involved in its formation. The crucial role of the Ca2+ ions in the process has not been confirmed. We showed that the Ca2+ ions affected the yPTP both with and without the Ca2+ ionophore ETH129 application insignificantly. This phenomenon in the E. magnusii yeast unites both mitochondrial unselective channel (ScMUC) features in the Saccharomyces cerevisiae mitochondria and the classical membrane pore in the mammalian ones (mPTP).
A Petrographic Investigation of the Carboniferous Sequence from the Ibbenbüren Mine: Tracing the Origin of the Coal Mine Drainage
Authors: Bedoya-Gonzalez Diego , Hilberg Sylke , Redhammer Günther , Rinder Thomas
Published: May 2021

The mine drainage of the Ibbenbüren anthracite coal mine is characterized by exceptionally high concentrations of dissolved iron and sulfate. The elevated position of the coal field with respect to the surrounding area makes the neighboring sediments an unlikely source of these elements. Accordingly, it has been hypothesized that interaction between infiltrating rainwater and the fractured overburden is a key process governing the mine drainage chemistry. To test this hypothesis, two full-diameter core samples drilled above the discharging adit of the coal mine were investigated. The methodology combined several analytical techniques to identify and characterize traces of water–rock interaction related to both diagenesis and relatively recent weathering processes along open fractures. The coupled appearance of kaolinite-dickite-illite minerals in weathered and unweathered rock sections was clearly connected to the burial history of the Carboniferous sequence. In contrast, the formation of iron (oxide-) hydroxides together with the presence of oxidized pyrite in weathering profiles along both sides of the fractures was positively related to the geochemical footprint of the coal mine drainage. Thus, open fractures, possibly originated from mining activities, may play a significant role in the drainage chemistry, especially considering the rather poor hydraulic conditions of the overburden.