bluuebunny/crossref_metadata_2025 huggingface dataset:
An Application of Urysohn Integral Equation via Complex Partial Metric Space
Authors: Ramaswamy Rajagopalan , Mani Gunaseelan , Gnanaprakasam Arul Joseph , Abdelnaby Ola A. Ashour , Radenović Stojan
Published: June 2022

Metric fixed point theory has vast applications in various domain areas, as it helps in finding analytical solutions under various contractive conditions, including non-linear integral-type contractions. In our present work, we have established fixed point results in the setting of complex valued partial metric space. Our results extend the results proven in literature. Using our main result, we have provided an application to find the solution to the Urysohn-type integral equation.
Largest Lyapunov Exponent Parameter of Stiffened Carbon Fiber Reinforced Epoxy Composite Laminated Plate Due to Critical Buckling Load Using Average Logarithmic Divergence Approach
Authors: Yousuf Louay S.
Published: June 2022

The purpose of this study is to calculate the bending deflection which is used to investigate the largest Lyapunov exponent due to buckling load. The design methodology is to calculate the largest Lyapunov exponent parameter at different thickness ratios and different fiber volume fractions using one and two stiffeners in order to reduce the chaotic phenomenon. The practical implication is to find the bending deflection using a strain gauge through a strain meter, in which this bending deflection is used in the algorithm of average logarithmic divergence to calculate the largest Lyapunov exponent experimentally. The experiment set up is carried out using Southwell plot when the upper head of the servo hydraulic cylinder moves downward. There are no limitations to this research, since it works on all kinds of composite materials, different thickness ratios, and different number of layers, different fiber volume fractions, and different boundary conditions. The findings of this work will allow us to detect the chaotic phenomenon in a stiffened carbon fiber reinforced epoxy composite laminated plate using the conception of the largest Lyapunov exponent parameter. The higher order shear deformation theory (HOSDT) of plates is used to analytically calculate the set of data of the bending deflection against time. All the systems used in this paper have non-periodic motion and chaos because the value of the Lyapunov parameter is above zero. The originality of this paper is the use of the algorithm code of average logarithmic divergence to investigate the value of the largest Lyapunov exponent parameter in the presence of stiffeners based on the bending deflection of a carbon epoxy composite laminated plate.
An Adaptive EWMA Control Chart Based on Principal Component Method to Monitor Process Mean Vector
Authors: Riaz Muhammad , Zaman Babar , Raji Ishaq Adeyanju , Omar M. Hafidz , Mehmood Rashid , Abbas Nasir
Published: June 2022

The special causes of variations, which is also known as a shift, can occur in a single or more than one related process characteristics. Statistical process control tools such as control charts are useful to monitor shifts in the process parameters (location and/or dispersion). In real-life situation, the shift is emerging in different sizes, and it is hard to identify it with classical control charts. Moreover, more than one process of characteristics required special attention because they must monitor jointly due to the association among them. This study offers two adaptive control charts to monitor the different sizes of a shift in the process mean vector. The novelty behind this study is to use dimensionally reduction techniques such as principal component analysis (PCA) and an adaptive method such as Huber and Bi-square functions. In brief, the multivariate cumulative sum control chart based on PCA is designed, and its plotting statistic is utilized as an input in the classical exponentially weighted moving average (EWMA) control chart. The run length (RL) properties of the proposed and other control charts are obtained by designing algorithms in MATLAB through a Monte Carlo simulation. For a single shift, the performance of the control charts is assessed through an average of RL, standard deviation of RL, and standard error of RL. Likewise, overall performance measures such as extra quadratic loss, relative ARL, and the performance comparison index are also used. The comparison reveals the superiority over other control charts. Furthermore, to emphasize the application process and benefits of the proposed control charts, a real-life example of the wind turbine process is included.
Home Production: Does It Matter for the Korean Macroeconomy during the COVID-19 Pandemic?
Authors: He Yugang
Published: June 2022

The COVID-19 pandemic has had a tremendous influence on many aspects of life in Korea. Some people have had to relocate their workplaces from factories or offices to their homes in order to stop the spread of the virus. This paper examines the effects of home production on the Korean macroeconomy during the COVID-19 pandemic. Then, the impulse response function is used to perform an empirical analysis. The results show that total output, market goods consumption, investment, capital, and market work hours all decline as a consequence of a home productivity shock, while home goods consumption, wages, transfer payments, and home work hours all increase. Moreover, using fiscal policies such as lowering the capital tax rate and increasing the fiscal deficit, the effect of the COVID-19 pandemic on the Korean macroeconomy can be improved. Robustness tests are carried out in light of the uneven economic development and different COVID-19 pandemic scenarios inside and outside the Seoul circle. The conclusions of this paper are accurate and reliable, as shown by the results of the robustness test.
Median Bernoulli Numbers and Ramanujan’s Harmonic Number Expansion
Authors: Chen Kwang-Wu
Published: June 2022

Ramanujan-type harmonic number expansion was given by many authors. Some of the most well-known are: Hn∼γ+logn−∑k=1∞Bkk·nk, where Bk is the Bernoulli numbers. In this paper, we rewrite Ramanujan’s harmonic number expansion into a similar form of Euler’s asymptotic expansion as n approaches infinity: Hn∼γ+c0(h)log(q+h)−∑k=1∞ck(h)k·(q+h)k, where q=n(n+1) is the nth pronic number, twice the nth triangular number, γ is the Euler–Mascheroni constant, and ck(x)=∑j=0kkjcjxk−j, with ck is the negative of the median Bernoulli numbers. Then, 2cn=∑k=0nnkBn+k, where Bn is the Bernoulli number. By using the result obtained, we present two general Ramanujan’s asymptotic expansions for the nth harmonic number. For example, Hn∼γ+12log(q+13)−1180(q+13)2∑j=0∞bj(r)(q+13)j1/r as n approaches infinity, where bj(r) can be determined.
Modified SHARK Cipher and Duffing Map-Based Cryptosystem
Authors: Rabie Osama , Ahmad Jawad , Alghazzawi Daniyal
Published: June 2022

Recent years have seen a lot of interest in the study of chaotic structures and their accompanying cryptography frameworks. In this research, we came up with a new way to encrypt images that used the chaos and a modified block cipher named the SHARK cipher. The new algorithm looks at the creation of random sequences as a problem that needs to be solved in the best way possible, and then it uses the Duffing chaotic map to get even better random sequences. Chaos has been combined with a revised edition of the SHARK structure to make the algorithm design more robust with increased confusion and diffusion. The offered algorithm includes a complex encryption and decryption structure with minimal time consumption for secure data transmission. The proposed algorithm is verified with the encryption of some standard images of different sizes. Numerous analyses have been performed to see how well the algorithm works against a variety of assaults, and the outcomes show that the cryptosystem has a good level of robustness. The comparative results are also performed in this work, which guarantees the excellent performance of our cryptosystem. The system is also subjected to chosen-plaintext and chosen-ciphertext attacks which implies that it can resist many classical cryptographic attacks. Therefore, our cryptosystem is robust enough to use for image encryption.
Linear Forest mP3 Plus a Longer Path Pn Becoming Antimagic
Authors: Shang Jen-Ling , Chang Fei-Huang
Published: June 2022

An edge labeling of a graph G is a bijection f from E(G) to a set of |E(G)| integers. For a vertex u in G, the induced vertex sum of u, denoted by f+(u), is defined as f+(u)=∑uv∈E(G)f(uv). Graph G is said to be antimagic if it has an edge labeling g such that g(E(G))={1,2,⋯,|E(G)|} and g+(u)≠g+(v) for any pair u,v∈V(G) with u≠v. A linear forest is a union of disjoint paths of orders greater than one. Let mPk denote a linear forest consisting of m disjoint copies of path Pk. It is known that mP3 is antimagic if and only if m=1. In this study, we add a disjoint path Pn (n≥4) to mP3 and develop a necessary condition and a sufficient condition whereby the new linear forest mP3⋃Pn may be antimagic.
The Complexity of Cryptocurrencies Algorithmic Trading
Authors: Cohen Gil , Qadan Mahmoud
Published: June 2022

In this research, we provided an answer to a very important trading question, what is the optimal number of technical tools in order to achieve the best trading results for both swing trade that uses daily bars and intraday trade that uses minutes bars? We designed Machine Learning (ML) systems that can trade four major cryptocurrencies: Bitcoin, Ethereum, BNB, and Solana. We found that more indicators do not necessarily mean better trading performance. Swing traders that use daily bars should trade Bitcoin and Solana using Ichimoku Cloud (IC) plus Moving Average Convergence Divergence (MACD), Ethereum with IC plus Chaikin Money Flow (CMF), and BNB with IC alone. With regard to intraday trading, we documented that different cryptocurrencies should be trading using different time frames. These results emphasize that the optimal number of indicators that are used to trade daily bars is one or, at maximum, two. The Multi-Layer (MUL) system that consists of all three examined technical indicators failed to improve the trading results for both days (swing) and intraday trades. The main implication of this study for traders is that more indicators does not necessarily improve trades performances.
A Generalized Bohr–Jessen Type Theorem for the Epstein Zeta-Function
Authors: Laurinčikas Antanas , Macaitienė Renata
Published: June 2022

Let Q be a positive defined n×n matrix and Q[x̲]=x̲TQx̲. The Epstein zeta-function ζ(s;Q), s=σ+it, is defined, for σ>n2, by the series ζ(s;Q)=∑x̲∈Zn\{0̲}(Q[x̲])−s, and is meromorphically continued on the whole complex plane. Suppose that n⩾4 is even and φ(t) is a differentiable function with a monotonic derivative. In the paper, it is proved that 1Tmeast∈[0,T]:ζ(σ+iφ(t);Q)∈A, A∈B(C), converges weakly to an explicitly given probability measure on (C,B(C)) as T→∞.
A Paternal Fish Oil Diet Preconception Modulates the Gut Microbiome and Attenuates Necrotizing Enterocolitis in Neonatal Mice
Authors: Rumph Jelonia T. , Stephens Victoria R. , Ameli Sharareh , Gaines Philip N. , Osteen Kevin G. , Bruner-Tran Kaylon L. , Nde Pius N.
Published: June 2022

Epidemiology and animal studies suggest that a paternal history of toxicant exposure contributes to the developmental origins of health and disease. Using a mouse model, our laboratory previously reported that a paternal history of in utero exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) increased his offspring’s risk of developing necrotizing enterocolitis (NEC). Additionally, our group and others have found that formula supplementation also increases the risk of NEC in both humans and mice. Our murine studies revealed that intervening with a paternal fish oil diet preconception eliminated the TCDD-associated outcomes that are risk factors for NEC (e.g., intrauterine growth restriction, delayed postnatal growth, and preterm birth). However, the efficacy of a paternal fish oil diet in eliminating the risk of disease development in his offspring was not investigated. Herein, reproductive-age male mice exposed to TCDD in utero were weaned to a standard or fish oil diet for one full cycle of spermatogenesis, then mated to age-matched unexposed females. Their offspring were randomized to a strict maternal milk diet or a supplemental formula diet from postnatal days 7–10. Offspring colon contents and intestines were collected to determine the onset of gut dysbiosis and NEC. We found that a paternal fish oil diet preconception reduced his offspring’s risk of toxicant-driven NEC, which was associated with a decrease in the relative abundance of the Firmicutes phylum, but an increase in the relative abundance of the Negativicutes class.
Kisspeptin Variations in Patients with Polycystic Ovary Syndrome—A Prospective Case Control Study
Authors: Akad Mona , Socolov Răzvan , Furnică Cristina , Covali Roxana , Stan Catalina Daniela , Crauciuc Eduard , Pavaleanu Ioana
Published: June 2022

Background and objectives: Kisspeptin, also named metastin, showed important roles in initiating the secretion of gonadotropin-releasing hormone (GnRH) and is an essential factor in the development of polycystic ovaries syndrome (PCOS). Several research studies noticed associations between kisspeptin levels and patients with anovulatory cycles due to PCOS with an increased LH/FSH ratio. The aim of our study was to bring scientific evidence regarding the correlation between high kisspeptin and luteinizing hormone values in subfertile women due to PCOS. Materials and Methods: A prospective case-control study was conducted in “Elena Doamna” Hospital of Obstetrics and Gynecology between 4 January 2021 and 1 March 2022. All patients agreed to participate in our study, had ages between 18 and 45 years old, and had a body mass index between 18.5 and 30 kg/m2. The study group consisted of subfertile patients with PCOS and menstrual disturbances, including amenorrhea or oligomenorrhea. The control group consisted of healthy patients with ovulatory cycles and no other reproductive or endocrinology pathologies. During the follicular phase of their menstrual cycle, patients had blood samples taken with the dosage of kisspeptin, LH, FSH, estradiol, insulin, glycemic levels, testosterone, and prolactin. Pelvic ultrasounds and clinical examinations were performed as well. Results: Significant differences were observed in kisspeptin, LH, FSH, and estradiol levels between patients with PCOS and the control group. After the univariate analysis, PCOS was significantly associated with increased kisspeptin, increased LH, and decreased FSH. There was no significant association between PCOS, estradiol, prolactin, and insulin. Conclusions: kisspeptin serum values are higher in subfertile PCOS patients, supporting the hypothesis that an over-stimulation of the KISS1 system might cause the hyper-stimulation of the HPG-axis.
Risk of Spine Surgery in Patients with Rheumatoid Arthritis: A Secondary Cohort Analysis of a Nationwide, Population-Based Health Claim Database
Authors: Chen Chien-Han , Hsu Chia-Wen , Lu Ming-Chi
Published: June 2022

Background and Objectives: To study the risk of spine surgery, including cervical and lumbar spine surgeries in patients with rheumatoid arthritis (RA) compared with those without a diagnosis of RA. Materials and Methods: This is a secondary data analysis using population-based health claim data. We identified newly diagnosed adult patients with RA between January 2000 and December 2012, according to the International Classification of Diseases, Ninth revision, clinical modification code 714.0 from Taiwan’s National Health Insurance Research Database. Using data frequency-matched by 10-year age intervals, sex and index year with the RA cohort at a ratio of 5:1, we assembled a comparison cohort. All patients were followed until the study outcomes occurred (overall spine surgery, cervical spine surgery, or lumbar spine surgery) or the end of follow-up. Adjusted incidence rate ratios (aIRR) were calculated using Poisson regression analysis with age group, socioeconomic status, geographical region, and osteoporosis included as potential confounders. Results: We identified 1287 patients with RA and 6435 patients without RA. The incidence of overall spine surgery (aIRR = 2.13, 95% confidence interval (CI) = 1.49–3.04) and lumbar spine surgery (aIRR = 2.14, 95% CI = 1.46–3.15) were all significantly higher in the RA cohort. Moreover, females over 45 years of age were particularly at risk for lumbar spine surgery. In RA patients, older age and the combination with the diagnosis of osteoporosis had an elevated risk for overall and lumbar spine surgery. Conclusion: Patients with RA had an increased risk of receiving spine surgery. Physicians should be vigilant for possible spinal problems in women and older patients with RA.
COVID-19 Elderly Patients Treated for Proximal Femoral Fractures during the Second Wave of Pandemic in Italy and Iran: A Comparison between Two Countries
Authors: Giorgino Riccardo , Soroush Erfan , Soroush Sajjad , Malakouti Sara , Salari Haniyeh , Vismara Valeria , Migliorini Filippo , Accetta Riccardo , Mangiavini Laura
Published: June 2022

Background and objevtive: The worldwide spread of SARS-CoV-2 has affected the various regions of the world differently. Italy and Iran have experienced a different adaptation to coexistence with the pandemic. Above all, fractures of the femur represent a large part of the necessary care for elderly patients. The aim of this study was to compare the treatment in Italy and Iran of COVID-19-positive patients suffering from proximal femur fractures in terms of characteristics, comorbidities, outcomes and complications. Materials and Methods: Medical records of COVID-19-positive patients with proximal femoral fractures treated at IRCCS Istituto Ortopedico Galeazzi in Milan (Italy) and at Salamat Farda and Parsa hospitals in the province of Tehran (Iran), in the time frame from 1 October 2020 to 16 January 2021, were analyzed and compared. Results: Records from 37 Italian patients and 33 Iranian patients were analyzed. The Italian group (mean age: 83.89 ± 1.60 years) was statistically older than the Iranian group (mean age: 75.18 ± 1.62 years) (p value = 0.0003). The mean number of transfusions for each patient in Italy was higher than the Iranian mean number (p value = 0.0062). The length of hospital stay in Italy was longer than in Iran (p value < 0.0001). Furthermore, laboratory values were different in the post-operative value of WBC and admission and post-operative values of CRP. Conclusions: The present study shows that differences were found between COVID-19-positive patients with proximal femoral fractures in these two countries. Further studies are required to validate these results and to better explain the reasons behind these differences.
Deuterium-Reinforced Polyunsaturated Fatty Acids Prevent Diet-Induced Nonalcoholic Steatohepatitis by Reducing Oxidative Stress
Authors: Li Haoran , Zhang Ouyang , Hui Chenmin , Huang Yaxin , Shao Hengrong , Song Menghui , Gao Lingjia , Jin Shengnan , Ding Chunming , Xu Liang
Published: June 2022

Background and Objectives: Oxidative stress is implicated in the progression of nonalcoholic steatohepatitis (NASH) through the triggering of inflammation. Deuterium-reinforced polyunsaturated fatty acids (D-PUFAs) are more resistant to the reactive oxygen species (ROS)−initiated chain reaction of lipid peroxidation than regular hydrogenated (H−) PUFAs. Here, we aimed to investigate the impacts of D-PUFAs on oxidative stress and its protective effect on NASH. Materials and Methods: C57BL/6 mice were randomly divided into three groups and were fed a normal chow diet, a methionine–choline-deficient (MCD) diet, and an MCD with 0.6% D-PUFAs for 5 weeks. The phenotypes of NASH in mice were determined. The levels of oxidative stress were examined both in vivo and in vitro. Results: The treatment with D-PUFAs attenuated the ROS production and enhanced the cell viability in tert-butyl hydroperoxide (TBHP)−loaded hepatocytes. Concurrently, D-PUFAs decreased the TBHP-induced oxidative stress in Raw 264.7 macrophages. Accordingly, D-PUFAs increased the cell viability and attenuated the lipopolysaccharide-stimulated proinflammatory cytokine expression of macrophages. In vivo, the administration of D-PUFAs reduced the phenotypes of NASH in MCD-fed mice. Specifically, D-PUFAs decreased the liver transaminase activity and attenuated the steatosis, inflammation, and fibrosis in the livers of NASH mice. Conclusion: D-PUFAs may be potential therapeutic agents to prevent NASH by broadly reducing oxidative stress.
Tracheal Glomus Tumor: A Case Report with CT Imaging Features
Authors: Yeom Jeong-A , Jeong Yeon-Joo , Ahn Hyo-Yeong , Eom Jung-Seop , Lee Chang-Hun , Hwang Min-Hee
Published: June 2022

Background and Objectives: Glomus tumors are rare benign tumors. The majority of them affect the skin the most and are rarer in the trachea, where the glomus bodies may not be present. Only scarce reports of tracheal glomus tumors have been reported solely with case reports of relevant articles. Materials and Methods: A 53-year-old man, with a free previous medial history, presented to our hospital with tracheal mass which was incidentally found. He did not complain of any specific symptoms associated with the tracheal tumor. The contrast-enhanced chest computed tomography (CT) revealed an avid enhancing nodular lesion, which is similar to blood vessels, in the trachea, 3 cm above the carina level without definite airway obstruction. Results: Successful tracheal resection and end-to-end anastomosis were performed on the patients; therefore, the final post-operative pathologic findings revealed a benign tracheal glomus tumor. The follow-up CT scan four months after operation showed complete removal of the tumor. Conclusion: Tracheal glomus tumors, even rare entities, could be considered as a differential diagnosis if a highly enhancing mass appears on CT images.
The Incidence of Venous Thromboembolism in Critically Ill Patients with SARS-CoV-2 Infection Compared with Critically Ill Influenza and Community-Acquired Pneumonia Patients: A Retrospective Chart Review
Authors: Boyd Sean , Sheng Loh Kai , Lynch Jessie , Alrashed Dhari , Muzzammil Saad , Marsh Hannah , Masoud Mustafa , Bin Ihsan Salman , Martin-Loeches Ignacio
Published: June 2022

The rate of venous thromboembolism in COVID-19 patients has been reported to be 30% (deep vein thrombosis 20% and pulmonary embolism 18%). This has been shown to be higher in COVID-19 patients admitted to the ICU. Prophylactic anticoagulation may be sufficient at ward level, but not in intensive care. A retrospective chart review was undertaken in a large university hospital. The review included 276 patients from COVID-19 Wave 1, COVID-19 Wave 2, influenza, and community-acquired pneumonia groups. The timeframe included patients admitted between 23 February 2014 and 12 May 2021. Clinical characteristics, outcomes, blood results, rates of venous thromboembolism, and anticoagulation status were recorded. The incidence of venous thromboembolism in COVID-19 Wave 1, COVID-19 Wave 2, influenza, and community-acquired pneumonia was 10.91%, 13.69%, 13.33%, and 6.81%, respectively (p = 0.481). The incidence of pulmonary embolism was 7.27%, 10.95%, 3.33%, and 5.68%, respectively (p = 0.350). The incidence of deep vein thrombosis was 5.45%, 5.48%, 10.00%, and 1.14%, respectively (p = 0.117). Although most patients were prophylactically anticoagulated, venous thromboembolism still occurred. Venous thromboembolism remains an important differential to consider in critically ill COVID-19 patients. The current literature does not advise therapeutic anticoagulation for thromboprophylaxis in the ICU.
Polyamine Depletion Strategies in Cancer: Remodeling the Tumor Immune Microenvironment to Enhance Anti-Tumor Responses
Authors: Chin Alexander , Bieberich Charles J. , Stewart Tracy Murray , Casero Robert A.
Published: June 2022

Polyamine biosynthesis is frequently dysregulated in cancers, and enhanced flux increases intracellular polyamines necessary for promoting cell growth, proliferation, and function. Polyamine depletion strategies demonstrate efficacy in reducing tumor growth and increasing survival in animal models of cancer; however, mechanistically, the cell-intrinsic and cell-extrinsic alterations within the tumor microenvironment underlying positive treatment outcomes are not well understood. Recently, investigators have demonstrated that co-targeting polyamine biosynthesis and transport alters the immune landscape. Although the polyamine synthesis-targeting drug 2-difluoromethylornithine (DFMO) is well tolerated in humans and is FDA-approved for African trypanosomiasis, its clinical benefit in treating established cancers has not yet been fully realized; however, combination therapies targeting compensatory mechanisms have shown tolerability and efficacy in animal models and are currently being tested in clinical trials. As demonstrated in pre-clinical models, polyamine blocking therapy (PBT) reduces immunosuppression in the tumor microenvironment and enhances the therapeutic efficacy of immune checkpoint blockade (ICB). Thus, DFMO may sensitize tumors to other therapeutics, including immunotherapies and chemotherapies.
A Comprehensive Analysis of Inorganic Ions and Their Selective Removal from the Reconstituted Tobacco Extract Using Electrodialysis
Authors: Ge Shaolin , Chen Qian , Zhang Zhao , She Shike , Xu Bingxia , Liu Fei , Afsar Noor Ul
Published: June 2022

Many tobacco stalks, dust, and fines are discharged in the tobacco industry, rich in inorganic minerals ions and nicotine salts. The high salinity and nicotine salts are challenging to be addressed by traditional treatment and are a severe threat that ought to be overcome. Thus, proper techniques can regenerate the tobacco stalks into reconstituted tobacco flakes used as cigarette filler. The electrodialysis process has been a viable approach to removing the inorganic ingredients in wastewater. We studied concentration, pH, and co-related influences with the nicotine and sugar/nicotine contents on the desalination performance. The results show that the inorganic ions such as Cl−, K+, Ca2+, and Mg2+ ions were successfully removed. When the feed concentration ranges from 3 to 15%, the removal ratio of the K+ ions is higher than Ca2+ and Mg2+ ions. As we reported previously, the K+ and Ca2+ ions are unfavorable for the total particulate matter emission but beneficial to decreasing the HCN delivery in mainstream cigarette smoke. Selective ED is a robust technology to reduce the harmful component delivery in cigarette smoke.
Effect of Electrode Type on Electrospun Membrane Morphology Using Low-Concentration PVA Solutions
Authors: Zelca Zane , Krumme Andres , Kukle Silvija , Viirsalu Mihkel , Vilcena Laimdota
Published: June 2022

Electrospun polymer nanofiber materials have been studied as basic materials for various applications. Depending on the intended use of the fibers, their morphology can be adjusted by changing the technological parameters, the properties of the spinning solutions, and the combinations of composition. The aim of the research was to evaluate the effect of electrode type, spinning parameters, polymer molecular weight, and solution concentration on membranes morphology. The main priority was to obtain the smallest possible fiber diameters and homogeneous electrospun membranes. As a result, five electrode types were selected, the lowest PVA solution concentration for stable spinning process was detected, spinning parameters for homogenous fibers were obtained, and the morphology of electrospun fiber membranes was analyzed. Viscosity, conductivity, pH, and density were evaluated for PVA polymers with five different molecular weights (30–145 kDa) and three concentration solutions (6, 8, and 10 wt.%). The membrane defects and fiber diameters were compared as a function of molecular weight and electrode type. The minimum concentration of PVA in the solution allowed more additives to be added to the solution, resulting in thinner diameters and a higher concentration of the additive in the membranes. The molecular weight, concentration, and electrode significantly affected the fiber diameters and the overall quality of the membrane.
Potentials for Describing Interatomic Interactions in γFe-Mn-C-N System
Authors: Lv Bo , Chen Chen , Zhang Fucheng , Poletaev Gennady M. , Rakitin Roman Y.
Published: June 2022

Potentials for describing interatomic interactions in a γFe-Mn-C-N multicomponent system, modified Hadfield steel, where face-centered cubic (f.c.c.) iron is the main component, are proposed. To describe the Fe-Fe interactions in austenite, it is proposed to use Lau EAM potential. For all other interactions, Morse potentials are proposed, the parameters of which were found from various experimental characteristics: in particular, the energy of dissolution and migration of an impurity in an f.c.c. iron crystal, the radius of atoms, their electronegativity, mutual binding energy, etc. The found potentials are intended for modeling the atomic structures and processes occurring at the atomic level in Hadfield steel using relatively large computational cells by the molecular dynamics method.
Influence Rule of Annular Notch Geometric Parameter on the Tubing Surface: A Case Study
Authors: Zhao Renfeng , Gao Weicheng , Zhang Dongya , Xiao Xudong , Liu Yanwei , Pan Runze , Fan Hongwei
Published: June 2022

In regards to the problem of tubing precision separation, the high-efficiency precision separation method for tubing under eccentric wheel high-speed rotational bending fatigue loading is proposed, which aims to promote the initiation of fatigue cracks at the root of the annular V-notch on the tubing surface. Research on the stress concentration effect of the annular notch on the tubing surface is carried out. The design of the notch takes into account the characteristics of tubing precision separation. The numerical simulation calculation includes four kinds of notches, namely, annular V-notch, annular U-notch, asymmetric V-notch towards the blanking end direction 45°, and asymmetric V-notch away from the blanking end direction 45°. The crack propagation lengths produced by each notch under the same experimental conditions are investigated experimentally. According to the findings, the annular V-notch is suitable for this separation method. By analyzing the theoretical stress concentration factor of the annular V-notch on the tubing surface, three main parameters affecting the annular V-notch root stress field are determined, namely, notch angle, notch depth, and notch root base angle radius. Through calculation and analysis, the influence law of tubing annular V-notch angle, notch depth, and notch root base angle radius on the stress concentration effect is obtained. Based on the process characteristics of tubing precision separation, the ideal tubing annular V-notch geometric parameter is presented within a reasonable value range. For the validation experiment of tubing precision separation, 45# steel, 304 stainless steel, and T2Y copper tube are selected, respectively. Finally, a great tubing precision separation effect is achieved, which verifies the reasonable selection of the tubing surface annular V-notch geometric parameter.
Kinetic Highlights of the Reduction of Silver Tungstate by Mg + C Combined Reducer
Authors: Zakaryan Marieta , Nazaretyan Khachik , Aydinyan Sofiya , Kharatyan Suren
Published: June 2022

The programmed reduction of tungstates and molybdates may yield the production of an intimate mixture of metals, pseudo-alloys or composite powders. As an extension of the study of obtaining powders of tungsten-copper, molybdenum-copper and tungsten-nickel from their respective salts, in the present study the reduction of silver tungstate was performed. Considering the extreme conditions for the synthesis of W-Ag alloys in the combustion wave and the limited toolkit for the study of the associated reduction mechanism, the interaction in the Ag2WO4-Mg-C system was modeled at high heating rates closer to the heating rates of reagents in the combustion wave, namely by the high-speed temperature scanner (HSTS). For the effective study of the interaction mechanism and calculation of the kinetic parameters of the individual stages, the heating rate of the reagents was changed in a wide range (from 100 to 1200 °C min−1). The interaction scheme and the sequence of the reactions along with their starting temperatures were deduced; the nature of intermediates formed during the reduction process and the microstructure evolution were monitored.
Design of High-Entropy Alloys
Authors: Stepanov Nikita , Zherebtsov Sergey
Published: June 2022

High-entropy alloys (HEAs) and related complex, concentrated alloys (CCAs) have resulted from new approaches to alloy design, which emerged 18 years ago [...]
Two Screening Assays to Detect Vancomycin-Resistant Enterococcus spp.
Authors: Cenci-Goga Beniamino T. , Karama Musafiri , El-Ashram Saeed , Saraiva Cristina , García-Díez Juan , Chalias Athanasios , Grispoldi Luca
Published: June 2022

Enterococci have become major nosocomial pathogens. An increasing number of these infections are as a result of vancomycin-resistant enterococci. Accurate detection of vancomycin-resistant enterococci (VRE) is important, so that appropriate therapy and infection control measures may be instituted, including veterinary surveillance. Two screening assays to detect vancomycin resistance in enterococci are proposed. Barnes Basal Medium agar (Ba) and Brain Heart Infusion (BHI) broth (plus 1% TTC-2,3,5-triphenyltetrazolium chloride) with several concentrations of vancomycin were used in this work. Five Enterococcus casseliflavus strains with low-level resistance to vancomycin (4 µg/mL) were used. Both media were able to quickly detect the breakpoint of the vancomycin-resistant strains used in this work, and also provided insight into the dynamics of the antibiotic effect at a low concentration on the tested bacterial suspensions.
Specific Detection and Enumeration of Burkholderia cepacia Complex by Flow Cytometry Using a Fluorescence-Labeled Oligonucleotide Probe
Authors: Daddy Gaoh Soumana , Williams Anna , Le David , Kweon Ohgew , Alusta Pierre , Buzatu Dan A. , Ahn Youngbeom
Published: June 2022

Burkholderia cepacia complex (BCC) contamination has resulted in recalls of non-sterile pharmaceutical products. The fast, sensitive, and specific detection of BCC is critical for ensuring the quality and safety of pharmaceutical products. In this study, a rapid flow cytometry-based detection method was developed using a fluorescence-labeled oligonucleotide Kef probe that specifically binds a KefB/KefC membrane protein sequence within BCC. Optimal conditions of a 1 nM Kef probe concentration at a 60 °C hybridization temperature for 30 min were determined and applied for the flow cytometry assay. The true-positive rate (sensitivity) and true-negative rate (specificity) of the Kef probe assay were 90% (18 positive out of 20 BCC species) and 88.9% (16 negative out of 18 non-BCC), respectively. The detection limit for B. cenocepacia AU1054 with the Kef probe flow cytometry assay in nuclease-free water was 1 CFU/mL. The average cell counts using the Kef probe assay from a concentration of 10 μg/mL chlorhexidine gluconate and 50 μg/mL benzalkonium chloride were similar to those of the RAPID-B total plate count (TPC). We demonstrate the potential of Kef probe flow cytometry as a more sensitive alternative to culture-based methods for detecting BCC in non-sterilized pharmaceutical raw materials and products with regards to water-based environments.
Detection of Cryptosporidium spp. and Giardia spp. in Environmental Water Samples: A Journey into the Past and New Perspectives
Authors: Fradette Marie-Stéphanie , Culley Alexander I. , Charette Steve J.
Published: June 2022

Among the major issues linked with producing safe water for consumption is the presence of the parasitic protozoa Cryptosporidium spp. and Giardia spp. Since they are both responsible for gastrointestinal illnesses that can be waterborne, their monitoring is crucial, especially in water sources feeding treatment plants. Although their discovery was made in the early 1900s and even before, it was only in 1999 that the U.S. Environmental Protection Agency (EPA) published a standardized protocol for the detection of these parasites, modified and named today the U.S. EPA 1623.1 Method. It involves the flow-through filtration of a large volume of the water of interest, the elution of the biological material retained on the filter, the purification of the (oo)cysts, and the detection by immunofluorescence of the target parasites. Since the 1990s, several molecular-biology-based techniques were also developed to detect Cryptosporidium and Giardia cells from environmental or clinical samples. The application of U.S. EPA 1623.1 as well as numerous biomolecular methods are reviewed in this article, and their advantages and disadvantages are discussed guiding the readers, such as graduate students, researchers, drinking water managers, epidemiologists, and public health specialists, through the ever-expanding number of techniques available in the literature for the detection of Cryptosporidium spp. and Giardia spp. in water.
Ectopic Expression of Plasmodium vivax vir Genes in P. falciparum Affects Cytoadhesion via Increased Expression of Specific var Genes
Authors: Rehn Torben , Lubiana Pedro , Nguyen Thi Huyen Trang , Pansegrau Eva , Schmitt Marius , Roth Lisa Katharina , Brehmer Jana , Roeder Thomas , Cadar Dániel , Metwally Nahla Galal , Bruchhaus Iris
Published: June 2022

Plasmodium falciparum-infected erythrocytes (PfIEs) adhere to endothelial cell receptors (ECRs) of blood vessels mainly via PfEMP1 proteins to escape elimination via the spleen. Evidence suggests that P. vivax-infected reticulocytes (PvIRs) also bind to ECRs, presumably enabled by VIR proteins, as shown by inhibition experiments and studies with transgenic P. falciparum expressing vir genes. To test this hypothesis, our study investigated the involvement of VIR proteins in cytoadhesion using vir gene-expressing P. falciparum transfectants. Those VIR proteins with a putative transmembrane domain were present in Maurer’s clefts, and some were also present in the erythrocyte membrane. The VIR protein without a transmembrane domain (PVX_050690) was not exported. Five of the transgenic P. falciparum cell lines, including the one expressing PVX_050690, showed binding to CD36. We observed highly increased expression of specific var genes encoding PfEMP1s in all CD36-binding transfectants. These results suggest that ectopic vir expression regulates var expression through a yet unknown mechanism. In conclusion, the observed cytoadhesion of P. falciparum expressing vir genes depended on PfEMP1s, making this experimental unsuitable for characterizing VIR proteins.
Mycobacterium chimaera Identification Using MALDI-TOF MS Technology: A Practical Approach for the Clinical Microbiology Laboratories
Authors: Bagnarino Jessica , Barbarini Daniela , Russello Giuseppe , Siciliano Mariangela , Monzillo Vincenzina , Baldanti Fausto , Carretto Edoardo
Published: June 2022

Mycobacterium chimaera (MC) is an environmental, slowly growing, non-tuberculous mycobacterium (NTM) belonging to Mycobacterium avium complex (MAC), which recently has been linked to severe cardiovascular infections following open heart and vascular surgery. The majority of the diagnostic laboratory tests used in routine are not able to distinguish MC from M. intracellulare (MI), because of the great genetic similarity existing between these two species. The Genotype Mycobacterium NTM-DR™ represents a valid method to differentiate between these species, but it is expensive, requiring also specialized personnel. Recently, MALDI-TOF MS has been proposed to identify relevant NTM. However, a software implementation is required to distinguish between MC and MI, presenting the two microorganisms’ overlapping spectra. The present study evaluates the feasibility of applying a MALDI-TOF logarithmic-based analysis in the routine of a clinical microbiology laboratory, and proposes an easy-to-use template spreadsheet to make the results quickly interpretable. The protocol was previously validated through the identification of 87 strains of MC/MI collected from clinical and environmental samples, and it was identified using the GenoType Mycobacterium NTM-DR™ and/or WGS. The proposed protocol provides accurate identification for the isolates tested; moreover, it is less expensive and more rapid than sequencing methods and can be implemented with minimum effort.
An Isolated Arthrobacter sp. Enhances Rice (Oryza sativa L.) Plant Growth
Authors: Chhetri Geeta , Kim Inhyup , Kang Minchung , So Yoonseop , Kim Jiyoun , Seo Taegun
Published: June 2022

Rice is a symbol of life and a representation of prosperity in South Korea. However, studies on the diversity of the bacterial communities in the rhizosphere of rice plants are limited. In this study, four bundles of root samples were collected from the same rice field located in Goyang, South Korea. These were systematically analyzed to discover the diversity of culturable bacterial communities through culture-dependent methods. A total of 504 culturable bacteria were isolated and evaluated for their plant growth-promoting abilities in vitro. Among them, Arthrobacter sp. GN70 was selected for inoculation into the rice plants under laboratory and greenhouse conditions. The results showed a significantly positive effect on shoot length, root length, fresh plant weight, and dry plant weight. Moreover, scanning electron microscopic (SEM) images demonstrated the accumulation of bacterial biofilm networks at the junction of the primary roots, confirming the root-colonizing ability of the bacterium. The strain also exhibited a broad spectrum of in vitro antimicrobial activities against bacteria and fungi. Here, we first report the rice plant growth-promoting ability of the Arthrobacter species with the biofilm-producing and antimicrobial activities against plant and human pathogens. Genome analyses revealed features attributable to enhance rice plant growth, including the genes involved in the synthesis of plant hormones, biofilm production, and secondary metabolites. This study revealed that the rhizobacteria isolated from the roots of rice plants have dual potential to be utilized as a plant growth promoter and antimicrobial agent.
Spontaneous Bacterial Peritonitis: The Incremental Value of a Fast and Direct Bacterial Identification from Ascitic Fluids Inoculated in Blood Culture Bottles by MALDI-TOF MS for a Better Management of Patients
Authors: Lotte Romain , Courdurié Audrey , Gaudart Alice , Emery Audrey , Chevalier Alicia , Tran Albert , Payen Mathilde , Ruimy Raymond
Published: June 2022

Spontaneous bacterial peritonitis (SBP) is a severe infection that requires fast and accurate antibiotic therapy to improve the patient outcome. Direct bacterial identification using MALDI-TOF mass spectrometry from ascitic fluid inoculated in blood culture bottles (BCBs) could therefore improve patients’ management. We evaluated the impact of the implementation of this method for the treatment of patients. Our identification protocol was performed on 136 positive BCBs collected from 61 patients between December 2018 and December 2020. The therapeutic impact of our protocol was evaluated using a before (2015–2016) and after (2019–2020) case–control study in two populations of 41 patients diagnosed with SBP and treated with antibiotics. The decrease in time to first identification and the optimization of antibiotic therapy following communication of the identification result were evaluated. Our protocol allowed us to identify 78% of bacteria in ascitic fluids. The transmission of the direct identification allowed the introduction or adaption of the antibiotic therapy early in 37% of SBP, with a mean decrease in time to first antibiotic change of 17 h. Our direct identification protocol for positive inoculated ascitic fluids is fast, reliable and inexpensive. Its routine integration into a microbiology laboratory allows the early introduction of appropriate antibiotic therapy and improves the management of patients with SBP.
Effects of Antibody Responses to Pre-Existing Coronaviruses on Disease Severity and Complement Activation in COVID-19 Patients
Authors: Cugno Massimo , Meroni Pier Luigi , Consonni Dario , Griffini Samantha , Grovetti Elena , Novembrino Cristina , Torri Adriana , Griffante Gloria , Gariglio Marisa , Varani Luca , Peyvandi Flora
Published: June 2022

The severity of coronavirus disease 2019 (COVID-19) may be influenced by pre-existing immune responses against endemic coronaviruses, but conflicting data have been reported. We studied 148 patients who were hospitalised because of a confirmed diagnosis of COVID-19, classified mild in 58, moderate in 44, and severe in 46. The controls were 27 healthy subjects. At admission, blood samples were collected for the measurement of biomarkers of disease severity and levels of the IgG against the receptor-binding domain (RBD) of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and pre-existing coronaviruses OC43, HKU1, NL63 and 229E. Higher levels of IgG antibodies against the RBD of pre-existing coronavirus (with the highest significance for anti-HKU1 IgG, p = 0.01) were found in patients with mild disease, compared with those with moderate or severe disease. Multivariable logistic regression confirmed the association of high levels of antibodies to pre-existing coronavirus with mild disease and showed their associations with low levels of the complement activation marker SC5b-9 (p range = 0.007–0.05). High levels of anti-NL63 antibodies were associated with low levels of the coagulation activation marker D-dimer (p = 0.04), while high levels of IgG against 229E were associated with low levels of the endothelial activation marker von Willebrand factor (p = 0.05). Anti-SARS-CoV-2-neutralising activity of plasma positively correlated with anti-SARS-CoV-2 IgG (r = 0.53, p = 0.04) and with anti-HKU1 IgG (r = 0.51, p = 0.05). In hospitalised patients with COVID-19, high levels of antibodies to pre-existing coronaviruses are associated with mild disease, suggesting that their measurement could be useful in predicting the severity of the disease.
Research Progress and Hopeful Strategies of Application of Quorum Sensing in Food, Agriculture and Nanomedicine
Authors: Abbamondi Gennaro Roberto , Tommonaro Giuseppina
Published: June 2022

Quorum sensing (QS) regulates the expression of several genes including motility, biofilm development, virulence expression, population density detection and plasmid conjugation. It is based on “autoinducers”, small molecules that microorganisms produce and release in the extracellular milieu. The biochemistry of quorum sensing is widely discussed and numerous papers are available to scientists. The main purpose of this research is to understand how knowledge about this mechanism can be exploited for the benefit of humans and the environment. Here, we report the most promising studies on QS and their resulting applications in different fields of global interest: food, agriculture and nanomedicine.