bluuebunny/crossref_metadata_2025 huggingface dataset:
Role of the Renin–Angiotensin–Aldosterone and Kinin–Kallikrein Systems in the Cardiovascular Complications of COVID-19 and Long COVID
Authors: Cooper Samantha L. , Boyle Eleanor , Jefferson Sophie R. , Heslop Calum R. A. , Mohan Pirathini , Mohanraj Gearry G. J. , Sidow Hamza A. , Tan Rory C. P. , Hill Stephen J. , Woolard Jeanette
Published: August 2021

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is the virus responsible for the COVID-19 pandemic. Patients may present as asymptomatic or demonstrate mild to severe and life-threatening symptoms. Although COVID-19 has a respiratory focus, there are major cardiovascular complications (CVCs) associated with infection. The reported CVCs include myocarditis, heart failure, arrhythmias, thromboembolism and blood pressure abnormalities. These occur, in part, because of dysregulation of the Renin–Angiotensin–Aldosterone System (RAAS) and Kinin–Kallikrein System (KKS). A major route by which SARS-CoV-2 gains cellular entry is via the docking of the viral spike (S) protein to the membrane-bound angiotensin converting enzyme 2 (ACE2). The roles of ACE2 within the cardiovascular and immune systems are vital to ensure homeostasis. The key routes for the development of CVCs and the recently described long COVID have been hypothesised as the direct consequences of the viral S protein/ACE2 axis, downregulation of ACE2 and the resulting damage inflicted by the immune response. Here, we review the impact of COVID-19 on the cardiovascular system, the mechanisms by which dysregulation of the RAAS and KKS can occur following virus infection and the future implications for pharmacological therapies.
Co-Treatment of Copper Oxide Nanoparticle and Carbofuran Enhances Cardiotoxicity in Zebrafish Embryos
Authors: Saputra Ferry , Uapipatanakul Boontida , Lee Jiann-Shing , Hung Shih-Min , Huang Jong-Chin , Pang Yun-Chieh , Muñoz John Emmanuel R. , Macabeo Allan Patrick G. , Chen Kelvin H.-C. , Hsiao Chung-Der
Published: August 2021

The use of chemicals to boost food production increases as human consumption also increases. The insectidal, nematicidal and acaricidal chemical carbofuran (CAF), is among the highly toxic carbamate pesticide used today. Alongside, copper oxide nanoparticles (CuO) are also used as pesticides due to their broad-spectrum antimicrobial activity. The overuse of these pesticides may lead to leaching into the aquatic environments and could potentially cause adverse effects to aquatic animals. The aim of this study is to assess the effects of carbofuran and copper oxide nanoparticles into the cardiovascular system of zebrafish and unveil the mechanism behind them. We found that a combination of copper oxide nanoparticle and carbofuran increases cardiac edema in zebrafish larvae and disturbs cardiac rhythm of zebrafish. Furthermore, molecular docking data show that carbofuran inhibits acetylcholinesterase (AChE) activity in silico, thus leading to impair cardiac rhythms. Overall, our data suggest that copper oxide nanoparticle and carbofuran combinations work synergistically to enhance toxicity on the cardiovascular performance of zebrafish larvae.
Differential Effects of 17,18-EEQ and 19,20-EDP Combined with Soluble Epoxide Hydrolase Inhibitor t-TUCB on Diet-Induced Obesity in Mice
Authors: Yang Yang , Xu Xinyun , Wu Haoying , Yang Jun , Chen Jiangang , Morisseau Christophe , Hammock Bruce D. , Bettaieb Ahmed , Zhao Ling
Published: August 2021

17,18-Epoxyeicosatetraenoic acid (17,18-EEQ) and 19,20-epoxydocosapentaenoic acid (19,20-EDP) are bioactive epoxides produced from n-3 polyunsaturated fatty acid eicosapentaenoic acid and docosahexaenoic acid, respectively. However, these epoxides are quickly metabolized into less active diols by soluble epoxide hydrolase (sEH). We have previously demonstrated that an sEH inhibitor, t-TUCB, decreased serum triglycerides (TG) and increased lipid metabolic protein expression in the brown adipose tissue (BAT) of diet-induced obese mice. This study investigates the preventive effects of t-TUCB (T) alone or combined with 19,20-EDP (T + EDP) or 17,18-EEQ (T + EEQ) on BAT activation in the development of diet-induced obesity and metabolic disorders via osmotic minipump delivery in mice. Both T + EDP and T + EEQ groups showed significant improvement in fasting glucose, serum triglycerides, and higher core body temperature, whereas heat production was only significantly increased in the T + EEQ group. Moreover, both the T + EDP and T + EEQ groups showed less lipid accumulation in the BAT. Although UCP1 expression was not changed, PGC1α expression was increased in all three treated groups. In contrast, the expression of CPT1A and CPT1B, which are responsible for the rate-limiting step for fatty acid oxidation, was only increased in the T + EDP and T + EEQ groups. Interestingly, as a fatty acid transporter, CD36 expression was only increased in the T + EEQ group. Furthermore, both the T + EDP and T + EEQ groups showed decreased inflammatory NFκB signaling in the BAT. Our results suggest that 17,18-EEQ or 19,20-EDP combined with t-TUCB may prevent high-fat diet-induced metabolic disorders, in part through increased thermogenesis, upregulating lipid metabolic protein expression, and decreasing inflammation in the BAT.
Platinum and Palladium Complexes as Promising Sources for Antitumor Treatments
Authors: Czarnomysy Robert , Radomska Dominika , Szewczyk Olga Klaudia , Roszczenko Piotr , Bielawski Krzysztof
Published: August 2021

There is a need for new, safer, and more effective agents to treat cancer. Cytostatics that have transition metals at their core have attracted renewed interest from scientists. Researchers are attempting to use chemotherapeutics, such as cisplatin, in combination therapy (i.e., in order to enhance their effectiveness). Moreover, studies are being carried out to modify molecules, by developing them into multinuclear structures, linking different compounds to commonly used drugs, or encapsulating them in nanoparticles to improve pharmacokinetic parameters, and increase the selectivity of these drugs. Therefore, we attempted to organize recent drug findings that contain palladium and platinum atoms in their structures.
Loss of swiss cheese in Neurons Contributes to Neurodegeneration with Mitochondria Abnormalities, Reactive Oxygen Species Acceleration and Accumulation of Lipid Droplets in Drosophila Brain
Authors: Melentev Pavel A. , Ryabova Elena V. , Surina Nina V. , Zhmujdina Darya R. , Komissarov Artem E. , Ivanova Ekaterina A. , Boltneva Natalia P. , Makhaeva Galina F. , Sliusarenko Mariana I. , Yatsenko Andriy S. , Mohylyak Iryna I. , Matiytsiv Nataliya P. , Shcherbata Halyna R. , Sarantseva Svetlana V.
Published: August 2021

Various neurodegenerative disorders are associated with human NTE/PNPLA6 dysfunction. Mechanisms of neuropathogenesis in these diseases are far from clearly elucidated. Hereditary spastic paraplegia belongs to a type of neurodegeneration associated with NTE/PNLPLA6 and is implicated in neuron death. In this study, we used Drosophila melanogaster to investigate the consequences of neuronal knockdown of swiss cheese (sws)—the evolutionarily conserved ortholog of human NTE/PNPLA6—in vivo. Adult flies with the knockdown show longevity decline, locomotor and memory deficits, severe neurodegeneration progression in the brain, reactive oxygen species level acceleration, mitochondria abnormalities and lipid droplet accumulation. Our results suggest that SWS/NTE/PNPLA6 dysfunction in neurons induces oxidative stress and lipid metabolism alterations, involving mitochondria dynamics and lipid droplet turnover in neurodegeneration pathogenesis. We propose that there is a complex mechanism in neurological diseases such as hereditary spastic paraplegia, which includes a stress reaction, engaging mitochondria, lipid droplets and endoplasmic reticulum interplay.
Senescence-Associated Glycine max (Gm)NAC Genes: Integration of Natural and Stress-Induced Leaf Senescence
Authors: Fraga Otto Teixeira , de Melo Bruno Paes , Quadros Iana Pedro Silva , Reis Pedro Augusto Braga , Fontes Elizabeth Pacheco Batista
Published: August 2021

Leaf senescence is a genetically regulated developmental process that can be triggered by a variety of internal and external signals, including hormones and environmental stimuli. Among the senescence-associated genes controlling leaf senescence, the transcriptional factors (TFs) comprise a functional class that is highly active at the onset and during the progression of leaf senescence. The plant-specific NAC (NAM, ATAF, and CUC) TFs are essential for controlling leaf senescence. Several members of Arabidopsis AtNAC-SAGs are well characterized as players in elucidated regulatory networks. However, only a few soybean members of this class display well-known functions; knowledge about their regulatory circuits is still rudimentary. Here, we describe the expression profile of soybean GmNAC-SAGs upregulated by natural senescence and their functional correlation with putative AtNAC-SAGs orthologs. The mechanisms and the regulatory gene networks underlying GmNAC081- and GmNAC030-positive regulation in leaf senescence are discussed. Furthermore, new insights into the role of GmNAC065 as a negative senescence regulator are presented, demonstrating extraordinary functional conservation with the Arabidopsis counterpart. Finally, we describe a regulatory circuit which integrates a stress-induced cell death program with developmental leaf senescence via the NRP-NAC-VPE signaling module.
Anti-Idiotype scFv Localizes an Autoepitope in the Globular Domain of C1q
Authors: Todorova Nadezhda , Rangelov Miroslav , Bogoeva Vanya , Stoyanova Vishnya , Yordanova Anna , Nikolova Ginka , Georgiev Hristo , Dimitrova Daniela , Mohedin Safa , Stoyanova Katerina , Tsacheva Ivanka
Published: August 2021

We addressed the issue of C1q autoantigenicity by studying the structural features of the autoepitopes recognized by the polyclonal anti-C1q antibodies present in Lupus Nephritis (LN) sera. We used six fractions of anti-C1q as antigens and selected anti-idiotypic scFv antibodies from the phage library “Griffin.1”. The monoclonal scFv A1 was the most potent inhibitor of the recognition of C1q and its fragments ghA, ghB and ghC, comprising the globular domain gC1q, by the lupus autoantibodies. It was sequenced and in silico folded by molecular dynamics into a 3D structure. The generated 3D model of A1 elucidated CDR similarity to the apical region of gC1q, thus mapping indirectly for the first time a globular autoepitope of C1q. The VH CDR2 of A1 mimicked the ghA sequence GSEAD suggested as a cross-epitope between anti-DNA and anti-C1q antibodies. Other potential inhibitors of the recognition of C1q by the LN autoantibodies among the selected recombinant antibodies were the monoclonal scFv F6, F9 and A12.
Mobility of Nucleostemin in Live Cells Is Specifically Related to Transcription Inhibition by Actinomycin D and GTP-Binding Motif
Authors: Pack Chan-Gi , Jung Keehoon , Paulson Bjorn , Kim Jun Ki
Published: August 2021

In vertebrates, nucleostemin (NS) is an important marker of proliferation in several types of stem and cancer cells, and it can also interact with the tumor-suppressing transcription factor p53. In the present study, the intra-nuclear diffusional dynamics of native NS tagged with GFP and two GFP-tagged NS mutants with deleted guanosine triphosphate (GTP)-binding domains were analyzed by fluorescence correlation spectroscopy. Free and slow binding diffusion coefficients were evaluated, either under normal culture conditions or under treatment with specific cellular proliferation inhibitors actinomycin D (ActD), 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB), or trichostatin A (TSA). When treated with ActD, the fractional ratio of the slow diffusion was significantly decreased in the nucleoplasm. The decrease was proportional to ActD treatment duration. In contrast, DRB or TSA treatment did not affect NS diffusion. Interestingly, it was also found that the rate of diffusion of two NS mutants increased significantly even under normal conditions. These results suggest that the mobility of NS in the nucleoplasm is related to the initiation of DNA or RNA replication, and that the GTP-binding motif is also related to the large change of mobility.
Corrosion Resistance of MgZn Alloy Covered by Chitosan-Based Coatings
Authors: Kozina Iryna , Krawiec Halina , Starowicz Maria , Kawalec Magdalena
Published: August 2021

Chitosan coatings are deposited on the surface of Mg20Zn magnesium alloy by means of the spin coating technique. Their structure was investigated using Fourier Transform Infrared Spectroscopy (FTIR) an X-ray photoelectron spectroscopy (XPS). The surface morphology of the magnesium alloy substrate and chitosan coatings was determined using Scanning Electron Microscope (FE-SEM) analysis. Corrosion tests (linear sweep voltamperometry and chronoamperometry) were performed on uncoated and coated magnesium alloy in the Hank’s solution. In both cases, the hydrogen evolution method was used to calculate the corrosion rate after 7-days immersion in the Hank’s solution at 37 °C. It was found that the corrosion rate is 3.2 mm/year and 1.2 mm/year for uncoated and coated substrates, respectively. High corrosion resistance of Mg20Zn alloy covered by multilayer coating (CaP coating + chitosan water glass) is caused by formation of CaSiO3 and Ca3(PO4)2 compounds on its surface.
N-Palmitoyl Serinol Stimulates Ceramide Production through a CB1-Dependent Mechanism in In Vitro Model of Skin Inflammation
Authors: Shin Kyong-Oh , Kim Sungeun , Park Byeong Deog , Uchida Yoshikazu , Park Kyungho
Published: August 2021

Ceramides, a class of sphingolipids containing a backbone of sphingoid base, are the most important and effective structural component for the formation of the epidermal permeability barrier. While ceramides comprise approximately 50% of the epidermal lipid content by mass, the content is substantially decreased in certain inflammatory skin diseases, such as atopic dermatitis (AD), causing improper barrier function. It is widely accepted that the endocannabinoid system (ECS) can modulate a number of biological responses in the central nerve system, prior studies revealed that activation of endocannabinoid receptor CB1, a key component of ECS, triggers the generation of ceramides that mediate neuronal cell fate. However, as the impact of ECS on the production of epidermal ceramide has not been studied, we here investigated whether the ECS stimulates the generation of epidermal ceramides in an IL-4-treated in vitro model of skin inflammation using N-palmitoyl serinol (PS), an analog of the endocannabinoid N-palmitoyl ethanolamine. Accordingly, an IL-4-mediated decrease in cellular ceramide levels was significantly stimulated in human epidermal keratinocytes (KC) following PS treatment through both de novo ceramide synthesis- and sphingomyelin hydrolysis-pathways. Importantly, PS selectively increases ceramides with long-chain fatty acids (FAs) (C22–C24), which mainly account for the formation of the epidermal barrier, through activation of ceramide synthase (CerS) 2 and Cer3 in IL-4-mediated inflamed KC. Furthermore, blockade of cannabinoid receptor CB1 activation by AM-251 failed to stimulate the production of total ceramide as well as long-chain ceramides in response to PS. These studies demonstrate that an analog of endocannabinoid, PS, stimulates the generation of specific ceramide species as well as the total amount of ceramides via the endocannabinoid receptor CB1-dependent mechanism, thereby resulting in the enhancement of epidermal permeability barrier function.
Cannabidiol Modulates the Motivational and Anxiety-Like Effects of 3,4-Methylenedioxypyrovalerone (MDPV) in Mice
Authors: Alegre-Zurano Laia , López-Arnau Raúl , Luján Miguel Á. , Camarasa Jordi , Valverde Olga
Published: August 2021

3,4-Methylenedioxypyrovalerone (MDPV) is a new psychoactive substance (NPS) and the most widespread and life-threatening synthetic cathinone of the “bath salts”. Preclinical research has proven the cocaine-like psychostimulant effects of MDPV and its potential for abuse. Cannabidiol (CBD) is a non-psychotropic phytocannabinoid that has emerged as a new potential treatment for drug addiction. Here, we tested the effects of CBD (20 mg/kg) on MDPV (2 mg/kg)-induced conditioned place preference and MDPV (0.05 and 0.075 mg/kg/infusion) self-administration paradigms. In addition, we assessed the effects of the co-administration of CBD and MDPV (3 and 4 mg/kg) on anxiety-like behaviour using the elevated plus maze (EPM). CBD mitigated the MDPV-induced conditioned place preference. On the contrary, CBD administration throughout the MDPV (0.075 mg/kg/infusion) self-administration increased drug-seeking and taking behaviours, but only in the high-responders group of mice. Furthermore, CBD exerted anxiolytic-like effects, exclusively in MDPV-treated mice. Taken together, our results indicate that CBD modulation of MDPV-induced motivational responses in mice varies depending on the requirements of the learning task, resulting in a complex response. Therefore, further research attempting to decipher the behavioural and molecular interactions between CBD and MDPV is needed.
Ecological Risks Due to Immunotoxicological Effects on Aquatic Organisms
Authors: Kataoka Chisato , Kashiwada Shosaku
Published: August 2021

The immunotoxic effects of some anthropogenic pollutants on aquatic organisms are among the causes of concern over the presence of these pollutants in the marine environment. The immune system is part of an organism’s biological defense necessarily for homeostasis. Thus, the immunotoxicological impacts on aquatic organisms are important to understand the effects of pollutant chemicals in the aquatic ecosystem. When aquatic organisms are exposed to pollutant chemicals with immunotoxicity, it results in poor health. In addition, aquatic organisms are exposed to pathogenic bacteria, viruses, parasites, and fungi. Exposure to pollutant chemicals has reportedly caused aquatic organisms to show various immunotoxic symptoms such as histological changes of lymphoid tissue, changes of immune functionality and the distribution of immune cells, and changes in the resistance of organisms to infection by pathogens. Alterations of immune systems by contaminants can therefore lead to the deaths of individual organisms, increase the general risk of infections by pathogens, and probably decrease the populations of some species. This review introduced the immunotoxicological impact of pollutant chemicals in aquatic organisms, including invertebrates, fish, amphibians, and marine mammals; described typical biomarkers used in aquatic immunotoxicological studies; and then, discussed the current issues on ecological risk assessment and how to address ecological risk assessment through immunotoxicology. Moreover, the usefulness of the population growth rate to estimate the immunotoxicological impact of pollution chemicals was proposed.
Postnatal Cytoarchitecture and Neurochemical Hippocampal Dysfunction in Down Syndrome
Authors: Moreno David G. , Utagawa Emma C. , Arva Nicoleta C. , Schafernak Kristian T. , Mufson Elliott J. , Perez Sylvia E.
Published: August 2021

Although the prenatal hippocampus displays deficits in cellular proliferation/migration and volume, which are later associated with memory deficits, little is known about the effects of trisomy 21 on postnatal hippocampal cellular development in Down syndrome (DS). We examined postnatal hippocampal neuronal profiles from autopsies of DS and neurotypical (NTD) neonates born at 38-weeks’-gestation up to children 3 years of age using antibodies against non-phosphorylated (SMI-32) and phosphorylated (SMI-34) neurofilament, calbindin D-28k (Calb), calretinin (Calr), parvalbumin (Parv), doublecortin (DCX) and Ki-67, as well as amyloid precursor protein (APP), amyloid beta (Aβ) and phosphorylated tau (p-tau). Although the distribution of SMI-32-immunoreactive (-ir) hippocampal neurons was similar at all ages in both groups, pyramidal cell apical and basal dendrites were intensely stained in NTD cases. A greater reduction in the number of DCX-ir cells was observed in the hippocampal granule cell layer in DS. Although the distribution of Calb-ir neurons was similar between the youngest and oldest NTD and DS cases, Parv-ir was not detected. Conversely, Calr-ir cells and fibers were observed at all ages in DS, while NTD cases displayed mainly Calr-ir fibers. Hippocampal APP/Aβ-ir diffuse-like plaques were seen in DS and NTD. By contrast, no Aβ1–42 or p-tau profiles were observed. These findings suggest that deficits in hippocampal neurogenesis and pyramidal cell maturation and increased Calr immunoreactivity during early postnatal life contribute to cognitive impairment in DS.
Negative Symptoms and Behavioral Alterations Associated with Dorsolateral Prefrontal Syndrome in Patients with Schizophrenia
Authors: Ruiz-Castañeda Pamela , Daza-González María Teresa , Santiago-Molina Encarnación
Published: August 2021

The present study had three main aims: (1) to explore the possible relationships between the two dimensions of negative symptoms (NS) with the three frontal behavioral syndromes (dorsolateral, orbitofrontal and the anterior or mesial cingulate circuit) in patients with schizophrenia; (2) to determine the influence of sociodemographic and clinical variables on the severity of the two dimensions of NS (expressive deficits and disordered relationships/avolition); and (3) to explore the possible relationships between the two dimensions of NS and social functioning. We evaluated a group of 33 patients with schizophrenia with a predominance of NS using the self-reported version of the Frontal System Behavior scale. To quantify the severity of NS, the Assessment of Negative Symptoms (SANS) scale was used. The results revealed that the two dimensions of NS correlate positively with the behavioral syndrome of dorsolateral prefrontal origin. Regarding the influence of sociodemographic and clinical variables, in patients with a long evolution the NS of the expressive deficits dimension were less severe than in patients with a short evolution. A negative correlation was found between the severity of NS of the disordered relationships/avolition dimension and perceived social functioning. Our results show the importance of differentiating between the two dimensions of NS to characterize better their possible frontal etiology and impact on clinical course and social functioning.
COVID-19 Pandemic-Related Depression and Insomnia among Psychiatric Patients and the General Population
Authors: Klimkiewicz Anna , Jasionowska Joanna , Schmalenberg Adrianna , Klimkiewicz Jakub , Jasińska Agata , Silczuk Andrzej
Published: August 2021

Background: The COVID-19 pandemic and limited access to healthcare professionals pose a serious risk of worsening mental conditions. This study was designed to examine the changes in symptoms of insomnia and depression during the pandemic as compared to before the pandemic, as well as the factors correlated with abovementioned mental state deterioration. Methods: The study was conducted from 1 April to 15 May 2020, on 212 psychiatric outpatients and 207 healthy controls. Participants completed a survey focused on symptoms during and prior to COVID-19 (the Beck Depression Inventory, the Athens Insomnia Scale). The following correlations were analyzed: demographics, social support, work status, income, and possible participants’ and their relatives’ COVID-19 diagnoses. Results: Insomnia and depression severity intensified during the pandemic in both groups and were associated with age, gender, education, employment, and financial status. No correlations between social support nor becoming sick with COVID-19 and insomnia or depression were observed. Maintaining work and enough money for one’s own needs were found to be significant protective factors of depression (OR 0.37 and 0.29, respectively). Conclusions: Exacerbation of insomnia and depression during the pandemic needs to be addressed. Economic crisis seems to influence mental state even more than COVID diagnosis among study subjects/relatives.
Effects of Statins on the Incidence and Mortality of Sepsis in Patients with New Cancer Diagnosis
Authors: Van de Louw Andry , Cohrs Austin , Leslie Douglas
Published: August 2021

Statins have been associated with improved survival in cancer patients and with decreased incidence and mortality of sepsis in different populations. Our objective was to assess whether newly diagnosed cancer patients on statins had decreased incidence and mortality of sepsis. We analyzed a US database and included 119,379 patients with a new cancer diagnosis (age 55 (50–60) years, 61% female), 19,468 of them (16%) receiving statins. Statins users were older and presented more comorbidities. After adjustment for baseline characteristics, statin use was associated with decreased death hazard (HR 0.897, 95% CI 0.851–0.945, p < 0.0001). The cumulative incidence of sepsis reached 10% at 5 years but statin use was not significantly associated with sepsis hazard (subdistribution hazard ratio 0.990, 95% CI 0.932–1.050, p = 0.73), including in sensitivity analyzes in patients with hematological malignancy or sepsis within 1 year. In patients subsequently hospitalized with sepsis, hospital mortality was 23% and statin use was not associated with mortality (odds ratio 0.952, 95% CI 0.829–1.091, p = 0.48), including in sensitivity analyzes in patients with septic shock and use of statins at the time of sepsis. In summary, treatment with statin at the time of new cancer diagnosis is not associated with a decreased incidence and mortality of sepsis.
The Influence of Bulb Position on Hydraulic Performance of Submersible Tubular Pump Device
Authors: Sun Zhuangzhuang , Yu Jie , Tang Fangping
Published: August 2021

In order to study the influence of the position of the bulb on the hydraulic performance of a submersible tubular pump device, based on a large-scale pumping station, two schemes—involving a front-mounted bulb and a rear-mounted bulb, respectively—were designed. The front-mounted scheme uses the GL-2008-03 hydraulic model and its conventional guide vane, while the rear-mounted scheme uses the optimized design of a diffuser vane. The method of combining numerical simulation and experimental testing was used to analyze the differences between the external and internal characteristics of the two schemes. The results show that, under the condition of reasonable diffusion guide vane design, the efficiency under the rear-mounted scheme is higher than that under the front-mounted scheme, where the highest efficiency difference is about 1%. Although the front-mounted bulb scheme reduces the hydraulic loss of the bulb section, the placement of the bulb on the water inlet side reduces the flow conditions of the impeller. Affected by the circulation of the guide vane outlet, the hydraulic loss of the outlet channel is greater than the rear-mounted scheme. The bulb plays a rectifying function when the bulb is placed behind, which greatly eliminates the annular volume of the guide vane outlet, and the water outlet channel has a smaller hydraulic loss. In the front-mounted scheme, the water flow inside the outlet channel squeezes to the outer wall, causing higher entropy production near the outer wall area. The entropy production of the rear-mounted scheme is mainly in the bulb section and the bulb support. This research can provide reference for the design and form selection of a submersible tubular pump device, which has great engineering significance.
Analysis of Wave-Induced Stokes Transport Effects on Sea Surface Temperature Simulations in the Western Pacific Ocean
Authors: Sun Zhanfeng , Shao Weizeng , Wang Weili , Zhou Wei , Yu Wupeng , Shen Wei
Published: August 2021

This study investigated the performance of two ocean wave models, that is, Simulation Wave Nearshore (SWAN) and WAVEWATCH-III (WW3), and the interannual and seasonal variability of transport induced by Stokes drift during the period from 1989 to 2019. Three types of sea surface wind products were used for wave simulation: the European Centre for Medium-Range Weather Forecasts (ECMWF) Interim, the Cross Calibrated Multi-Platform Version 2.0 (CCMP V2.0) from Remote Sensing Systems (RSS), and the National Centers for Environmental Prediction (NCEP) Global Forecast System (GFS). The modeling was validated against wave measurements from the Jason-2 altimeter in 2015. The analysis found that the root mean square error (RMSE) of significant wave height (SWH) from the WW3 model using CCMP wind data was 0.17 m, which is less than the ~0.6-m RMSE of SWH from the SWAN model using the other types of wind data. The simulations from the WW3 model using CCMP wind data indicated that the Stokes transport is up to 2 m2/s higher in the South China Sea and Japan Sea than that at other ocean regions in January. The interannual variation showed that the Stokes transport generally increased from 0.25 m2/s in 1989 to 0.35 m2/s in 2018. We also found that the accuracy of the sea surface temperature (SST) simulation using the Stony Brook Parallel Ocean Model (sbPOM) is improved by as much as 0.5 °C when Stokes transport is considered to validate the sbPOM-simulated SST against the measurements from Argo in 2012–2015. In particular, the Stokes transport has a negative effect on Summer (March to June) and has a positive effect in Autumn (July to September), which is probably caused by the tropical cyclones.
Impact of Pneumococcal Urinary Antigen Testing in COVID-19 Patients: Outcomes from the San Matteo COVID-19 Registry (SMACORE)
Authors: Valsecchi Pietro , Colaneri Marta , Zuccaro Valentina , Asperges Erika , Costanzo Filippo , Mariani Bianca , Roda Silvia , Minucci Rita , Bertuccio Francesco , Fraolini Elia , Bosio Matteo , Tirelli Claudio , Oggionni Tiberio , Corsico Angelo , Bruno Raffaele
Published: August 2021

Despite low rates of bacterial co-infections, most COVID-19 patients receive antibiotic therapy. We hypothesized that patients with positive pneumococcal urinary antigens (PUAs) would benefit from antibiotic therapy in terms of clinical outcomes (death, ICU admission, and length of stay). The San Matteo COVID-19 Registry (SMACORE) prospectively enrolls patients admitted for COVID-19 pneumonia at IRCCS Policlinico San Matteo, Pavia. We retrospectively extracted the data of patients tested for PUA from October to December 2020. Demographic, clinical, and laboratory data were recorded. Of 469 patients, 42 tested positive for PUA (8.95%), while 427 (91.05%) tested negative. A positive PUA result had no significant impact on death (HR 0.53 CI [0.22–1.28] p-value 0.16) or ICU admission (HR 0.8; CI [0.25–2.54] p-value 0.70) in the Cox regression model, nor on length of stay in linear regression (estimate 1.71; SE 2.37; p-value 0.47). After adjusting for age, we found no significant correlation between urinary antigen positivity and variations in the WHO ordinal scale and laboratory markers at admission and after 14 days. We found that a positive PUA result was not frequent and had no impact on clinical outcomes or clinical improvement. Our results did not support the routine use of PUA tests to select COVID-19 patients who will benefit from antibiotic therapy.
Urban Ecosystem Services: Current Knowledge, Gaps, and Future Research
Authors: Russo Alessio , Cirella Giuseppe T.
Published: August 2021

The term ecosystem services was coined to describe the societal benefit that natural ecosystems provide, as well as to raise awareness about biodiversity and ecosystem conservation [...]
1-Tosyl-6-vinyl-4,5,6,7-tetrahydro-1H-benzo [d] imidazole-2-amine
Authors: Meany Fiach B. , O’Rourke Sarah , Murphy Paul V.
Published: August 2021

The alkene functionalised 2-aminobenzimidazole ring found in terrazoanthine natural products was synthesized in 3 steps from 1,2-epoxy-4-vinylcyclohexane via epoxide ring opening with toluenesulphonamide yielding 2 regioisomeric, separable amino alcohols. One isomer was oxidized to the corresponding ketone and subsequently condensed with cyanamide to furnish the title compound, which was characterized by 1H-NMR and 13C-NMR spectroscopy.
Lean Wrought Magnesium Alloys
Authors: Papenberg Nikolaus P. , Gneiger Stefan , Uggowitzer Peter J. , Pogatscher Stefan
Published: August 2021

Lean magnesium alloys are considered attractive candidates for easy and economical hot forming. Such wrought alloys, defined here as materials with a maximum alloying content of one atomic or two weight percent, are known to achieve attractive mechanical properties despite their low alloy content. The good mechanical properties and the considerable hardening potential, combined with the ease of processing, make them attractive for manufacturers and users alike. This results in potential uses in a wide range of applications, from rolled or extruded components to temporary biomedical implants. The characteristic behavior of these alloys and the optimal use of suitable alloying elements are discussed and illustrated exemplarily.
Synthesis of Highly Energetic PolyNitrogen by Nanosecond-Pulsed Plasma in Liquid Nitrogen
Authors: Dobrynin Danil , Song Zhiheng , Fridman Alexander
Published: August 2021

We report on an experimental study of nanosecond-pulsed plasma treatment of liquid nitrogen demonstrating synthesis of a highly energetic nitrogen material. Raman, FTIR analysis of gas phase products of decomposition, and the material explosion characteristics suggest synthesis of polymeric (amorphous) nitrogen compound which is stable at ambient pressure up to temperatures of about −150 °C. Addition of adsorbents with relatively large characteristic pore sizes (>5 nm) allows marginally improved recovery of the material as determined by temperature-dependent Raman measurements. By analyzing the shock wave propagation resulting from the explosions, we estimated the energy density of the material to be 13.3 ± 3.5 kJ/g, close to the previously predicted value for amorphous polymeric nitrogen.
Low and High Speed Orthogonal Cutting of AA6061-T6 under Dry and Flood-Coolant Modes: Tool Wear and Residual Stress Measurements and Predictions
Authors: Javidikia Mahshad , Sadeghifar Morteza , Songmene Victor , Jahazi Mohammad
Published: August 2021

The present research work aimed to study the effects of cutting environments and conditions on tool wear and residual stresses induced by orthogonal cutting of AA6061-T6. Cutting environments included dry- and flood-coolant modes and cutting conditions consisted of cutting speed and feed rate. A 2D finite element (FE) model was developed to predict tool wear and residual stresses and was validated by experimental measurements including machining forces, tool wear, and residual stresses. This was obtained by exploring various magnitudes of the shear friction factor and heat transfer coefficient and choosing proper coefficients using the calibration of the predicted results with the measured ones. The experimental results showed that the effect of cutting environment including dry and flood-coolant modes was negligible on machining forces. The experimental investigation also demonstrated that increasing feed rate raised machining forces, tool wear and residual stresses in both cutting environments. Low Speed Cutting (LSC) led to the highest value of tool wear and High Speed Cutting (HSC) provided the lowest values of resultant machining forces and residual stresses in both modes. Flood-coolant mode reduced tool wear and slightly decreased tensile residual stresses in comparison with dry mode. As a result, low feed rate and high-speed cutting under flood-coolant mode were proposed in order to improve tool wear and residual stress in orthogonal cutting of AA6061-T6.
Slicing Algorithm and Partition Scanning Strategy for 3D Printing Based on GPU Parallel Computing
Authors: Lai Xuhui , Wei Zhengying
Published: August 2021

Aiming at the problems of over stacking, warping deformation and rapid adjustment of layer thickness in electron beam additive manufacturing, the 3D printing slicing algorithm and partition scanning strategy for numerical control systems are studied. The GPU (graphics processing unit) is used to slice the 3D model, and the STL (stereolithography) file is calculated in parallel according to the normal vector and the vertex coordinates. The voxel information of the specified layer is dynamically obtained by adjusting the projection matrix to the slice height. The MS (marching squares) algorithm is used to extract the coordinate sequence of the binary image, and the ordered contour coordinates are output. In order to avoid shaking of the electron gun when the numerical control system is forming the microsegment straight line, and reduce metal overcrowding in the continuous curve C0, the NURBS (non-uniform rational b-splines) basis function is used to perform curve interpolation on the contour data. Aiming at the deformation problem of large block components in the forming process, a hexagonal partition and parallel line variable angle scanning technology is adopted, and an effective temperature and deformation control strategy is formed according to the European-distance planning scan order of each partition. The results show that the NURBS segmentation fits closer to the original polysurface cut line, and the error is reduced by 34.2% compared with the STL file slice data. As the number of triangular patches increases, the algorithm exhibits higher efficiency, STL files with 1,483,132 facets can be cut into 4488 layers in 89 s. The slicing algorithm involved in this research can be used as a general data processing algorithm for additive manufacturing technology to reduce the waiting time of the contour extraction process. Combined with the partition strategy, it can provide new ideas for the dynamic adjustment of layer thickness and deformation control in the forming process of large parts.
FCG Modelling Considering the Combined Effects of Cyclic Plastic Deformation and Growth of Micro-Voids
Authors: Sérgio Edmundo R. , Antunes Fernando V. , Borges Micael F. , Neto Diogo M.
Published: August 2021

Fatigue is one of the most prevalent mechanisms of failure. Thus, the evaluation of the fatigue crack growth process is fundamental in engineering applications subjected to cyclic loads. The fatigue crack growth rate is usually accessed through the da/dN-ΔK curves, which have some well-known limitations. In this study a numerical model that uses the cyclic plastic strain at the crack tip to predict da/dN was coupled with the Gurson–Tvergaard–Needleman (GTN) damage model. The crack propagation process occurs, by node release, when the cumulative plastic strain reaches a critical value. The GTN model is used to account for the material degradation due to the growth of micro-voids process, which affects fatigue crack growth. Predictions with GTN are compared with the ones obtained without this ductile fracture model. Crack closure was studied in order to justify the lower values of da/dN obtained in the model with GTN, when compared with the results without GTN, for lower ΔK values. Finally, the accuracy of both variants of the numerical model is accessed through the comparison with experimental results.
Interdiffusion and Intermetallic Compounds at Al/Cu Interfaces in Al-50vol.%Cu Composite Prepared by Solid-State Sintering
Authors: Kim Dasom , Kim Kyungju , Kwon Hansang
Published: August 2021

Al–Cu composites have attracted significant interest recently owing to their lightweight nature and remarkable thermal properties. Understanding the interdiffusion mechanism at the numerous Al/Cu interfaces is crucial to obtain Al–Cu composites with high thermal conductivities. The present study systematically investigates the interdiffusion mechanism at Al/Cu interfaces in relation to the process temperature. Al-50vol.%Cu composite powder, where Cu particles were encapsulated in a matrix of irregular Al particles, was prepared and then sintered at various temperatures from 340 to 500 °C. Intermetallic compounds (ICs) such as CuAl2 and Cu9Al4 were formed at the Al/Cu interfaces during sintering. Microstructural analysis showed that the thickness of the interdiffusion layer, which comprised the CuAl2 and Cu9Al4 ICs, drastically increased above 400 °C. The Vickers hardness of the Al-50vol.%Cu composite sintered at 380 °C was 79 HV, which was 1.5 times that of the value estimated by the rule of mixtures. A high thermal conductivity of 150 W∙m−1∙K−1 was simultaneously obtained. This result suggests that the Al-50vol.%Cu composite material with large number of Al/Cu interfaces, as well as good mechanical strength and heat conductance, can be prepared by solid-state sintering at a low temperature.
Evaluation of Stresses on Implant, Bone, and Restorative Materials Caused by Different Opposing Arch Materials in Hybrid Prosthetic Restorations Using the All-on-4 Technique
Authors: Haroun Feras , Ozan Oguz
Published: August 2021

The long-term success of dental implants is greatly influenced by the use of appropriate materials while applying the “All-on-4” concept in the edentulous jaw. This study aims to evaluate the stress distribution in the “All-on-4” prosthesis across different material combinations using three-dimensional finite element analysis (FEA) and to evaluate which opposing arch material has destructive effects on which prosthetic material while offering certain recommendations to clinicians accordingly. Acrylic and ceramic-based hybrid prosthesis have been modelled on a rehabilitated maxilla using the “All-on-4” protocol. Using different materials and different supports in the opposing arch (natural tooth, and implant/ceramic, and acrylic), a multi-vectorial load has been applied. To measure stresses in bone, maximum and minimum principal stress values were calculated, while Von Mises stress values were obtained for prosthetic materials. Within a single group, the use of an acrylic implant-supported prosthesis as an antagonist to a full arch implant-supported prosthesis yielded lower maximum (Pmax) and minimum (Pmin) principal stresses in cortical bone. Between different groups, maxillary prosthesis with polyetheretherketone as framework material showed the lowest stress values among other maxillary prostheses. The use of rigid materials with higher moduli of elasticity may transfer higher stresses to the peri implant bone. Thus, the use of more flexible materials such as acrylic and polyetheretherketone could result in lower stresses, especially upon atrophic bones.
Preparation of Breathable Cellulose Based Polymeric Membranes with Enhanced Water Resistance for the Building Industry
Authors: Hussain Atif , Blanchet Pierre
Published: August 2021

This study focuses on the development of advanced water-resistant bio-based membranes with enhanced vapour permeability for use within building envelopes. Building walls are vulnerable to moisture damage and mold growth due to water penetration, built-in moisture, and interstitial condensation. In this work, breathable composite membranes were prepared using micro-fibrillated cellulose fiber (CF) and polylactic acid (PLA). The chemical composition and physical structure of CF is responsible for its hydrophilic nature, which affects its compatibility with polymers and consequently its performance in the presence of excessive moisture conditions. To enhance the dispersibility of CF in the PLA polymer, the fibers were treated with an organic phosphoric acid ester-based surfactant. The hygroscopic properties of the PLA-CF composites were improved after surfactant treatment and the membranes were resistant to water yet permeable to vapor. Morphological examination of the surface showed better interfacial adhesion and enhanced dispersion of CF in the PLA matrix. Thermal analysis revealed that the surfactant treatment of CF enhanced the glass transition temperature and thermal stability of the composite samples. These bio-based membranes have immense potential as durable, eco-friendly, weather resistant barriers for the building industry as they can adapt to varying humidity conditions, thus allowing entrapped water vapor to pass through and escape the building, eventually prolonging the building life.
Perturbation of Wavelet Frames of Quaternionic-Valued Functions
Authors: Xiao Fusheng , He Jianxun
Published: August 2021

Let L2(R,H) denote the space of all square integrable quaternionic-valued functions. In this article, let Φ∈L2(R,H). We consider the perturbation problems of wavelet frame {Φm,n,a0,b0,m,n∈Z} about translation parameter b0 and dilation parameter a0. In particular, we also research the stability of irregular wavelet frame {SmΦ(Smx−nb),m,n∈Z} for perturbation problems of sampling.
A Class of k-Symmetric Harmonic Functions Involving a Certain q-Derivative Operator
Authors: Srivastava Hari M. , Khan Nazar , Khan Shahid , Ahmad Qazi Zahoor , Khan Bilal
Published: August 2021

In this paper, we introduce a new class of harmonic univalent functions with respect to k-symmetric points by using a newly-defined q-analog of the derivative operator for complex harmonic functions. For this harmonic univalent function class, we derive a sufficient condition, a representation theorem, and a distortion theorem. We also apply a generalized q-Bernardi–Libera–Livingston integral operator to examine the closure properties and coefficient bounds. Furthermore, we highlight some known consequences of our main results. In the concluding part of the article, we have finally reiterated the well-demonstrated fact that the results presented in this article can easily be rewritten as the so-called (p,q)-variations by making some straightforward simplifications, and it will be an inconsequential exercise, simply because the additional parameter p is obviously unnecessary.
On the Ternary Exponential Diophantine Equation Equating a Perfect Power and Sum of Products of Consecutive Integers
Authors: Subburam S. , Nkenyereye Lewis , Anbazhagan N. , Amutha S. , Kameswari M. , Cho Woong , Joshi Gyanendra
Published: August 2021

Consider the Diophantine equation yn=x+x(x+1)+⋯+x(x+1)⋯(x+k), where x, y, n, and k are integers. In 2016, a research article, entitled – ’power values of sums of products of consecutive integers’, primarily proved the inequality n= 19,736 to obtain all solutions (x,y,n) of the equation for the fixed positive integers k≤10. In this paper, we improve the bound as n≤ 10,000 for the same case k≤10, and for any fixed general positive integer k, we give an upper bound depending only on k for n.
Molecular Networking-Guided Isolation of New Etzionin-Type Diketopiperazine Hydroxamates from the Persian Gulf Sponge Cliona celata
Authors: Kouchaksaraee Reza Mohsenian , Li Fengjie , Nazemi Melika , Farimani Mahdi Moridi , Tasdemir Deniz
Published: August 2021

The Persian Gulf is a unique and biologically diverse marine environment dominated by invertebrates. In continuation of our research interest in the chemistry and biological activity of marine sponges from the Persian Gulf, we selected the excavating sponge Cliona celata for detailed metabolome analyses, in vitro bioactivity screening, and chemical isolation studies. A UPLC-MS/MS (MS2) molecular-networking-based dereplication strategy allowed annotation and structural prediction of various diketopiperazines (DKPs) and etzionin-type diketopiperazine hydroxamates (DKPHs) in the crude sponge extract. The molecular-networking-guided isolation approach applied to the crude extract afforded the DKPH etzionin (1) and its two new derivatives, clioetzionin A (2) and clioetzionin B (3). Another new modified DKP (4) was identified by MS/MS analyses but could not be isolated in sufficient quantities to confirm its structure. The chemical characterization of the purified DKPHs 1–3 was performed by a combination of 1D and 2D NMR spectroscopy, HRMS, HRMS/MS, and [α]D analyses. Compounds 1 and 2 exhibited broad antibacterial, antifungal, and anticancer activities, with IC50 values ranging from 19.6 to 159.1 µM. This is the first study investigating the chemical constituents of a C. celata specimen from the Persian Gulf. It is also the first report of full spectroscopic data of etzionin based on extensive spectroscopic analyses.