bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of Meandering River Morphodynamics Using Satellite Remote Sensing Data—An Application in the Lower Deduru Oya (River), Sri Lanka
Authors: Basnayaka Vindhya , Samarasinghe Jayanga T. , Gunathilake Miyuru B. , Muttil Nitin , Hettiarachchi Dileepa C. , Abeynayaka Amila , Rathnayake Upaka
Published: July 2022

River meandering and anabranching have become major problems in many large rivers that carry significant amounts of sediment worldwide. The morphodynamics of these rivers are complex due to the temporal variation of flows. However, the availability of remote sensing data and geographic information systems (GISs) provides the opportunity to analyze the morphological changes in river systems both quantitatively and qualitatively. The present study investigated the temporal changes in the river morphology of the Deduru Oya (river) in Sri Lanka, which is a meandering river. The study covered a period of 32 years (1989 to 2021), using Landsat satellite data and the QGIS platform. Cloud-free Landsat 5 and Landsat 8 satellite images were extracted and processed to extract the river mask. The centerline of the river was generated using the extracted river mask, with the support of semi-automated digitizing software (WebPlotDigitizer). Freely available QGIS was used to investigate the temporal variation of river migration. The results of the study demonstrated that, over the past three decades, both the bend curvatures and the river migration rates of the meandering bends have generally increased with time. In addition, it was found that a higher number of meandering bends could be observed in the lower (most downstream) and the middle parts of the selected river segment. The current analysis indicates that the Deduru Oya has undergone considerable changes in its curvature and migration rates.
Revealing the Land Use Volatility Process in Northern Southeast Asia
Authors: Rao Yongheng , Zhang Jianjun
Published: July 2022

Frequent land use change has generally been considered as a consequence of human activities. Here, we revealed the land use volatility process in northern Southeast Asia (including parts of Myanmar, Thailand, Laos, Vietnam, and China) from 2000 to 2018 with LandTrendr in the Google Earth Engine (GEE) platform based on the Normalized Burning Index (NBR). The result showed that land use volatility with similar degrees had very obvious aggregation characteristics in time and space in the study area, and the time for the occurrence of land use volatility in adjacent areas was often relatively close. This trend will become more obvious with the intensity of land use volatility. At the same time, land use volatility also has obvious spillover effects, and strong land use volatility will drive changes in the surrounding land. If combined with the land use/cover types, which are closely related to human activities that could have more severe land use volatility, and with the increase of the volatility intensity, the proportion of the land use type with strong land use volatility will gradually increase. Revealing the land use volatility process has a possibility to deepen the understanding of land use change and to help formulate land use policy.
Hereditary Hemorrhagic Telangiectasia Associating Neuropsychiatric Manifestations with a Significant Impact on Disease Management—Case Report and Literature Review
Authors: Sârbu Fabiola , Oprea Violeta Diana , Tatu Alin Laurențiu , Polea Drima Eduard , Bojincă Violeta Claudia , Romila Aurelia
Published: July 2022

(1) Background: Genetic hereditary hemorrhagic telangiectasia (HHT) is clinically diagnosed. The clinical manifestations and lack of curative therapeutic interventions may lead to mental illnesses, mainly from the depression–anxiety spectrum. (2) Methods: We report the case of a 69-year-old patient diagnosed with HHT and associated psychiatric disorders; a comprehensive literature review was performed based on relevant keywords. (3) Results: Curaçao diagnostic criteria based the HHT diagnosis in our patient case at 63 years old around the surgical interventions for a basal cell carcinoma, after multiple episodes of epistaxis beginning in childhood, but with a long symptom-free period between 20 and 45 years of age. The anxiety–depressive disorder associated with nosocomephobia resulted in a delayed diagnosis and low adherence to medical monitoring. A comprehensive literature review revealed the scarcity of publications analyzing the impact of psychiatric disorders linked to this rare condition, frequently associating behavioral disengagement as a coping strategy, psychological distress, anxiety, depression, and hopelessness. (4) Conclusions: As patients with HHT face traumatic experiences from disease-related causes as well as recurring emergency hospital visits, active monitoring for mental illnesses and psychological support should be considered as part of the initial medical approach and throughout the continuum of care.
MitoTEMPOL Inhibits ROS-Induced Retinal Vascularization Pattern by Modulating Autophagy and Apoptosis in Rat-Injected Streptozotocin Model
Authors: Virgana Rova , Atik Nur , Gunadi Julia Windi , Jonathan Evelyn , Ramadhani Dona Erisa , Soetadji Ray Sebastian , Goenawan Hanna , Lesmana Ronny , Kartasasmita Arief
Published: July 2022

Diabetic retinopathy leads to retinal malfunction, blindness, and reduced quality of life in adult diabetes patients. The involvement of reactive oxygen species (ROS) regulation stimulated by high blood glucose levels opens the opportunity for ROS modulator agents such as MitoTEMPOL. This study aims to explore the effect of MitoTEMPOL on ROS balance that may be correlated with retinal vascularization pattern, autophagy, and apoptosis in a streptozotocin-induced rat model. Four groups of male Wistar rats (i.e., control, TEMPOL (100 mg/kg body weight [BW]), diabetic (streptozotocin, 50 mg/kg BW single dose), and diabetic + TEMPOL; n = 5 for each group) were used in the study. MitoTEMPOL was given for 5 weeks, followed by funduscopy, and gene and protein expression were explored from the rat’s retina. Streptozotocin injection decreased bodyweight and increased food and water intake, as well as fasting blood glucose. The results showed that MitoTEMPOL reduced retinal vascularization pattern and decreased superoxide dismutase gene expression and protein carbonyl, caspase 3, and caspase 9 protein levels. A modulation of autophagy in diabetes that was reversed in the diabetic + TEMPOL group was found. In conclusion, MitoTEMPOL modulation on autophagy and apoptosis contributes to its role as a potent antioxidant to prevent diabetic retinopathy by inhibiting ROS-induced retinal vascularization patterns.
Meta-Analysis of RNA Sequencing Data of Arabidopsis and Rice under Hypoxia
Authors: Tamura Keita , Bono Hidemasa
Published: July 2022

Hypoxia is an abiotic stress in plants. Flooding resulting from climate change is a major crop threat that increases the risk of hypoxic stress. The molecular mechanisms underlying hypoxia in plants were elucidated in recent years, but new genes related to this stress remain to be discovered. Thus, we aimed to perform a meta-analysis of the RNA sequencing (RNA-Seq) data of Arabidopsis (Arabidopsis thaliana) and rice (Oryza sativa) under hypoxia. We collected 29 (Arabidopsis) and 26 (rice) pairs of RNA-Seq data involving hypoxic (including submergence) and normoxic (control) treatments and extracted the genes that were commonly upregulated or downregulated in the majority of the experiments. The meta-analysis revealed 40 and 19 commonly upregulated and downregulated genes, respectively, in the two species. Several WRKY transcription factors and cinnamate-4-hydroxylase were commonly upregulated, but their involvement in hypoxia remains unclear. Our meta-analysis identified candidate genes for novel molecular mechanisms in plants under hypoxia.
Testing for the Presence of the Leverage Effect without Estimation
Authors: Liu Zhi
Published: July 2022

Problem: The leverage effect plays an important role in finance. However, the statistical test for the presence of the leverage effect is still lacking study. Approach: In this paper, by using high frequency data, we propose a novel procedure to test if the driving Brownian motion of an Ito^ semi-martingale is correlated to its volatility (referred to as the leverage effect in financial econometrics) over a long time period. The asymptotic setting is based on observations within a long time interval with the mesh of the observation grid shrinking to zero. We construct a test statistic via forming a sequence of Studentized statistics whose distributions are asymptotically normal over blocks of a fixed time span, and then collect the sequence based on the whole data set of a long time span. Result: The asymptotic behaviour of the Studentized statistics was obtained from the cubic variation of the underlying semi-martingale and the asymptotic distribution of the proposed test statistic under the null hypothesis that the leverage effect is absent was established, and we also show that the test has an asymptotic power of one against the alternative hypothesis that the leverage effect is present. Implications: We conducted extensive simulation studies to assess the finite sample performance of the test statistics, and the results show a satisfactory performance for the test. Finally, we implemented the proposed test procedure to a dataset of the SP500 index. We see that the null hypothesis of the absence of the leverage effect is rejected for most of the time period. Therefore, this provides a strong evidence that the leverage effect is a necessary ingredient in modelling high-frequency data.
Mini-Review on the Harlequin Syndrome—A Rare Dysautonomic Manifestation Requiring Attention
Authors: Mavroudis Ioannis , Balmus Ioana-Miruna , Ciobica Alin , Luca Alina-Costina , Chowdhury Rumana , Iordache Alin-Constantin , Gorgan Dragos Lucian , Radu Iulian
Published: July 2022

Harlequin syndrome (HS) is a rare autonomic disorder. The causes and risk factors of the disease are not fully understood. Some cases of HS are associated with traumatic injuries, tumors, or vascular impairments of the head. Symptoms of HS can also occur in some autoimmune disorders, ophthalmic disorders, sleep disorders, and with certain organic lesions. In this context, a thorough review of the pathophysiology of HS in relation to neurological, ophthalmological, and dermatological conditions is necessary. In this mini-review, we aim to review the pathophysiological changes and underlying mechanisms in primary and secondary HS. Additionally, we discuss possible management approaches for patients with HS in light of the discussed pathological mechanisms. The main symptoms of HS that are correlated with autonomic nervous system impairments include sudden unilateral flushing of the face, neck, chest, and rarely arm, with concurrent contralateral anhidrosis. Despite reported co-occurring syndromes (such as cluster headaches), several studies have shown that HS could frequently overlap with other syndromes that are disruptive to the idiopathic nerve pathways. HS usually does not require any medical treatment. In some severe cases, symptomatic treatments could be needed. However, total symptomatic relief may not be achieved in many cases of HS. We therefore suggest an approach to comprehensive management of HS, which may lead to better long-term control of HS.
Emphysema Quantification Using Ultra-Low-Dose Chest CT: Efficacy of Deep Learning-Based Image Reconstruction
Authors: Yeom Jeong-A , Kim Ki-Uk , Hwang Minhee , Lee Ji-Won , Kim Kun-Il , Song You-Seon , Lee In-Sook , Jeong Yeon-Joo
Published: July 2022

Background and Objectives: Although reducing the radiation dose level is important during diagnostic computed tomography (CT) applications, effective image quality enhancement strategies are crucial to compensate for the degradation that is caused by a dose reduction. We performed this prospective study to quantify emphysema on ultra-low-dose CT images that were reconstructed using deep learning-based image reconstruction (DLIR) algorithms, and compared and evaluated the accuracies of DLIR algorithms versus standard-dose CT. Materials and Methods: A total of 32 patients were prospectively enrolled, and all underwent standard-dose and ultra-low-dose (120 kVp; CTDIvol < 0.7 mGy) chest CT scans at the same time in a single examination. A total of six image datasets (filtered back projection (FBP) for standard-dose CT, and FBP, adaptive statistical iterative reconstruction (ASIR-V) 50%, DLIR-low, DLIR-medium, DLIR-high for ultra-low-dose CT) were reconstructed for each patient. Image noise values, emphysema indices, total lung volumes, and mean lung attenuations were measured in the six image datasets and compared (one-way repeated measures ANOVA). Results: The mean effective doses for standard-dose and ultra-low-dose CT scans were 3.43 ± 0.57 mSv and 0.39 ± 0.03 mSv, respectively (p < 0.001). The total lung volume and mean lung attenuation of five image datasets of ultra-low-dose CT scans, emphysema indices of ultra-low-dose CT scans reconstructed using ASIR-V 50 or DLIR-low, and the image noise of ultra-low-dose CT scans that were reconstructed using DLIR-low were not different from those of standard-dose CT scans. Conclusions: Ultra-low-dose CT images that were reconstructed using DLIR-low were found to be useful for emphysema quantification at a radiation dose of only 11% of that required for standard-dose CT.
Vitamins C and D and COVID-19 Susceptibility, Severity and Progression: An Evidence Based Systematic Review
Authors: Migliorini Filippo , Vaishya Raju , Eschweiler Jörg , Oliva Francesco , Hildebrand Frank , Maffulli Nicola
Published: July 2022

Background and Objectives: Starting in early December 2019, the novel Coronavirus Disease (COVID-19) from infection with COVID-19 has caused a global pandemic. Many aspects of its pathogenesis and related clinical consequences are still unclear. Early diagnosis and dynamic monitoring of prognostic factors are essential to improve the ability to manage COVID-19 infection. This study aimed to provide an account of the role played by vitamins C and D on the onset, progression and severity of COVID-19. Clinical features and infection-related risk factors are also briefly discussed. Material and Methods: In March 2022, the main online databases were accessed. All the articles that investigate the possible role of vitamins C and D on COVID-19 susceptibility, severity and progression were considered. Results: The current evidence on vitamin C and D supplementation in patients with COVID-19 infection is inconsistent and controversial. In some studies, vitamins were used as coadjuvant of a formal experimental therapy, while in others as main treatment. Ethnicity and hospital setting (inpatient/outpatient) were also variable. Moreover, there was no consensus between studies in administration protocol: high heterogeneity in dosage, administration, and duration of the treatment were evident. Finally, some studies administered vitamins pre- and/or during COVID infection, in patients with different risk factors and infection severity. Conclusions: While waiting to develop a targeted, safe and effective therapy, it is important to investigate individual predisposition and proper disease management. Concluding, available data on the use of nutraceuticals in COVID-19 are inconsistent. However, there is a lack of evidence-based guidelines which recommend vitamin C and D supplementation in patients with COVID-19, and results from high quality randomised controlled trials (RCTs) are inconsistent. Current investigations so far are mostly observational, and include a relatively small sample size which can lead to biased results. Large-scale multicentre studies are therefore needed.
Anxiety and Depression in Women with Polycystic Ovary Syndrome
Authors: Dybciak Paweł , Humeniuk Ewa , Raczkiewicz Dorota , Krakowiak Jan , Wdowiak Artur , Bojar Iwona
Published: July 2022

Background and Objectives: Mental health disorders are often the consequence of hormonal disorders such as those accompanying polycystic ovary syndrome (PCOS), where changes in appearance and having to deal with a number of other problems occur due to this illness. The objective of this study was to determine the prevalence and severity of anxiety and depression symptoms, the level of ego-resiliency, and the ways that women with PCOS cope with stress compared to healthy women in order to determine the influence of socio-demographic characteristics in relation to levels of anxiety and depression with ego-resiliency and stress-coping methods. Materials and Methods: The study was conducted in Poland in 2021 and included 230 women with PCOS and 199 healthy controls aged 20–40 years old. The hospital anxiety and depression scale (HADs), ego-resiliency scale, as well as the MINI-COPE inventory were used. Results: The women with PCOS had higher levels of anxiety and depression and poorer ego-resiliency in comparison to the healthy women. The women with PCOS used passive stress-coping strategies significantly more commonly than the healthy women. Living in rural areas, having a lower level of education and being childless increased anxiety levels. Similarly, being over 30, living in a rural area, having a lower level of education, being childless, and being obese increased depression levels in the women with PCOS. A low level of ego-resiliency and passive stress-coping strategies are predictors of high levels of anxiety and depression in women with PCOS. Conclusions: Women with PCOS should be checked for anxiety and depression. They should also be checked to see whether they have the resources to cope with chronic stress in order to optimize therapeutic interventions.
The First Evaluation of Proteinase K-Resistant Prion Protein (PrPSc) in Korean Appendix Specimens
Authors: Won Sae-Young , Kim Yong-Chan , Lee Yu-Ni , Park Chan-Gyun , Kim Woo-Young , Jeong Byung-Hoon
Published: July 2022

Background and Objectives: Prion diseases are fatal neurodegenerative disorders caused by the abnormal proteinase K-resistant prion protein (PrPSc). Since variant Creutzfeldt–Jakob disease (CJD) was first reported in the United Kingdom (UK) in 1996, the occurrence of variant CJD has been reported in over 10 countries. To date, variant CJD has not been reported in Korea. However, the E211K somatic mutation in the prion protein gene (PRNP), which is related to bovine spongiform encephalopathy (BSE), was reported in Korean Holstein cattle, and atypical BSE, which is supposed to be sporadic BSE, has been occurring in many countries, including Japan and the USA. These results suggest that BSE may occur naturally in Korea. Thus, we performed a preemptive PrPSc test in appendix specimens to diagnose variant CJD in a Korean population. Materials and Methods: In the present study, we investigated CJD-related mutations and polymorphisms of the PRNP gene and carried out an examination on PrPSc in appendix specimens of Korean patients after appendectomy. Results: In all Korean appendix specimens tested, PrPSc bands were not detected. Conclusion: To the best of our knowledge, this was the first evaluation of PrPSc in Korean appendix specimens.
Theoretical Analysis of Grinding Wheel Deflection Angle on Peripheral Grinding Parameters and Grinding Force
Authors: Chen Changhao , Chen Bin , Wu Chaoqun , Gu Xinghua , Liu Xuehai , Guo Feng
Published: July 2022

The peripheral surface of the grinding wheel can grind the rail according to the envelope of the contour of the rail surface, thus a fuller and smoother rail surface can be obtained. Specifically, a better grinding effect can be obtained in that the end face of the grinding wheel deviates from the longitudinal section of the rail at a certain angle. Based on the traditional grinding technology theory, the mathematical models of the peripheral grinding parameters (kinematic contact arc length, wheel-rail grinding contact area, and maximum undeformed chip thickness) and the grinding force are established, in which the angle exists between the grinding wheel end face and the rail longitudinal section. The main influence of grinding wheel circumferential speed, grinding wheel kinematic speed, and the deflection angle of the grinding wheel end face on the grinding parameters and the force are analyzed. The result shows that: when there is angle θ in the models, the ratios of peripheral grinding parameters between up-grinding and down-grinding varies monotonically with the increase in vm, and their maximum variation range is about 12%, vs has the greatest influence on the peripheral grinding parameters, and the maximum variation range of the ratios is about 20% when the vs is 10 m/s. With the increase in the grinding width, Fa’ cannot be ignored and will increase gradually with the increase in angle θ. The analysis and conclusion have guiding significance for the structural design, grinding control strategy, and experimental research regarding rail curved surface grinding equipment.
Advances in Anti-Corrosion Polymeric and Paint Coatings on Metals: Preparation, Adhesion, Characterization and Application
Authors: Petrunin Maxim A.
Published: July 2022

Metals currently remain the main structural material used by various industries for many centuries [...]
Coffee Drinking and Adverse Physical Outcomes in the Aging Adult Population: A Systematic Review
Authors: Mazeaud Simon , Castellana Fabio , Coelho-Junior Hélio , Panza Francesco , Rondanelli Mariangela , Fassio Federico , De Pergola Giovanni , Zupo Roberta , Sardone Rodolfo
Published: July 2022

Declining physical functioning covers a prominent span of later life and, as a modifiable driver to be leveraged, lifestyle plays a critical role. This research aimed to undertake a systematic review investigating the association between levels of coffee consumption and declining conditions of physical functioning during aging, such as sarcopenia, frailty, weakness, falls, and disability, while trying to explain the underlying mechanisms, both from a metabolic and social angle. The literature was reviewed from inception to May 2022 using different electronic databases, not excluding the grey literature. Two independent researchers assessed the eligibility of 28 retrieved articles based on inclusion criteria; only 10 met the eligibility requirements. Different levels of coffee consumption were considered as exposure(s) and comparator(s) according to PECO concepts, while middle age was an inclusion criterion (40+ years). No limitations were set on the tool(s) assessing physical functioning, type of dietary assessment(s), study setting, general health status, country, and observational study design (cohort, cross-sectional). The cross-sectional design outnumbered the longitudinal (90%, n = 9/10). The overall quality rating was judged poor (70%) to good (30%). It was found that higher exposure to coffee drinking is strongly associated with better physical functioning outcomes, and the findings showed consistency in the direction of association across selected reports. Countering physical decline is a considerable challenge in easing the burden of population aging. For preventive models that aim to allow a better lifestyle, it has to be kept in mind that increased coffee consumption does not lead to poor physical functioning.
Sustained Endurance Training Leads to Metabolomic Adaptation
Authors: Weiss Astrid , Alack Katharina , Klatt Stephan , Zukunft Sven , Schermuly Ralph , Frech Torsten , Mooren Frank-Christoph , Krüger Karsten
Published: July 2022

Endurance training induces several adaptations in substrate metabolism, especially in relation to glycogen conservation. The study aimed to investigate differences in the metabolism of lipids, lipid-like substances, and amino acids between highly trained and untrained subjects using targeted metabolomics. Depending on their maximum relative oxygen uptake (VO2max), subjects were categorized as either endurance-trained (ET) or untrained (UT). Resting blood was taken and plasma isolated. It was screened for changes of 345 metabolites, including amino acids and biogenic amines, acylcarnitines, glycerophosphocholines (GPCs), sphingolipids, hexoses, bile acids, and polyunsaturated fatty acids (PUFAs) by using liquid chromatography coupled to tandem mass spectrometry. Acylcarnitine (C14:1, down in ET) and five GPCs (lysoPC a C18:2, up in ET; PC aa C42:0, up in ET; PC ae C38:2, up in ET; PC aa C38:5, down in ET; lysoPC a C26:0, down in ET) were differently regulated in ET compared to UT. TCDCA was down-regulated in athletes, while for three ratios of bile acids CA/CDCA, CA/(GCA+TCA), and DCA/(GDCA+TDCA) an up-regulation was found. TXB2 and 5,6-EET were down-regulated in the ET group and 18S-HEPE, a PUFA, showed higher levels in 18S-HEPE in endurance-trained subjects. For PC ae C38:2, TCDCA, and the ratio of cholic acid to chenodeoxycholic acid, an association with VO2max was found. Numerous phospholipids, acylcarnitines, glycerophosphocholines, bile acids, and PUFAs are present in varying concentrations at rest in ET. These results might represent an adaptation of lipid metabolism and account for the lowered cardiovascular risk profile of endurance athletes.
Analytical Approach for a Heat Transfer Process through Nanofluid over an Irregular Porous Radially Moving Sheet by Employing KKL Correlation with Magnetic and Radiation Effects: Applications to Thermal System
Authors: Khan Umair , Zaib Aurang , Ishak Anuar , Waini Iskandar , Raizah Zehba , Galal Ahmed M.
Published: July 2022

The aluminum nanoparticle is adequate for power grid wiring, such as the distribution of local power and the transmission of aerial power lines, because of its higher conductivity. This nanoparticle is also one of the most commonly used materials in applications in the electrical field. Thus, in this study, a radiative axisymmetric flow of Casson fluid, induced by water-based Al2O3 nanofluid by using the Koo–Kleinstreuer–Li (KKL) correlation, is investigated. The impact of the magnetic field is also taken into account. KKL correlation is utilized to compute the thermal conductivity and effective viscosity. Analytical double solutions are presented for the considered axisymmetric flow model after implementing the similarity technique to transmute the leading equations into ordinary differential equations. The obtained analytic forms were used to examine and discuss the velocity profile, the temperature distribution, reduced heat transfer, and coefficient of reduced skin friction. The analytic solutions indicate that the velocity profile decreases in the branch of the first solution and uplifts in the branch of the second solution due to the presence of an aluminum particle, whereas the dimensionless temperature enhances in both solutions. In addition, the Casson parameter increases the friction factor, as well as the heat transport rate.
Design and Measurement of a Novel Overmoded TE01 Mode Converter for a Rectangular Gyro-TWT
Authors: Lu Chaoxuan , Jiang Wei , Wu Zewei , Liu Guo , Wang Jianxun , Pu Youlei , Luo Yong
Published: July 2022

The rectangular gyrotron traveling wave tube (gyro-TWT) with a large aspect ratio (α) has the potential to achieve megawatt-class output power. As an essential component of gyro-TWT, a novel overmoded Ka-band mode converter with an α of 6.19 is designed, analyzed, and cold tested in this paper. Based on the magnetic dipole moment theory, the rectangular overmoded TE01 mode is excited via the rectangular fundamental TE10 mode. The cutoff waveguide is applied to prevent electromagnetic wave transport to the magnetron injection gun (MIG) region and also guarantee higher power electron beam transportation. Simulations predict an operation bandwidth higher than 4 GHz and greater than 99.8% mode purity between 33–37 GHz. To verify this design, the mode converter is manufactured and cold tested. The back-to-back measurement results exhibit a good agreement with the simulation. With similar topologies, the rectangular overmoded TE01 mode can be excited in a different α.
Ultra-Precision Cutting and Characterization of Reflective Convex Spherical Blazed Grating Elements
Authors: Li Huang , Peng Xiaoqiang , Guan Chaoliang , Hu Hao
Published: July 2022

In this work, based on the diffraction principle of reflective blazed grating, the structure size of the convex spherical blazed grating unit is determined, the machining accuracy of the convex spherical blazed grating is formulated, the effects of tool nose radius and Poisson burr on the diffraction efficiency of the convex spherical blazed grating are analyzed, and the performances of cutting convex gratings with microcrystalline aluminum RSA6061 and RSA6061+ chemically plated NiP for two workpiece materials are compared. A convex spherical blazed grating with a radius of curvature R = 41.104 mm, substrate diameter 14 mm, grating density 53.97 line/mm, and blaze angle of roughly 3.8° is turned by a four-axis ultra-precision machining system by adjustment of the cutting tool, workpiece material, and cutting parameters, as well as modification of the layouts of the blazed grating on the convex sphere. The results of the testing of convex spherical blazed grating elements in both layouts show that the size error of the grating period is close for both layouts, the size error of grating height is smaller in the equal-along-arc layout, the blaze angle error in the equal-along-projection layout is only 0.74%, and the average roughness of the blazed surface is less than 5 nm to meet the processing quality requirements of the reflective convex spherical blazed grating. The greater the blaze angle accuracy of the blazed grating, the higher its diffraction efficiency, so the grating element with an equal-along-projection layout has a higher diffraction efficiency than the grating element with an equal-along-arc layout. RSA6061+ chemically plated NiP material is superior to RSA6061 material in Poisson burr height and blazed surface roughness, which is more suitable for Offner-type imaging spectrometers in the spectral range 0.95–2.5 μm (SWIR).
A General FEM Model for Analysis of Third-Order Nonlinearity in RF Surface Acoustic Wave Devices Based on Perturbation Theory
Authors: Li Baichuan , Zhang Qiaozhen , Zhao Xiangyong , Zhi Shaotao , Qiu Luyan , Fu Sulei , Wang Weibiao
Published: July 2022

This article presents a general-purpose model that enables efficient and accurate calculation of third-order nonlinear signals in surface acoustic wave (SAW) devices. This model is based on piezoelectric constitutive equations combined with perturbation theory, which can be analyzed by full finite element method (FEM). For validation, third-order harmonic (H3) responses and intermodulation distortions (IMD3) in SAW resonators are simulated, and their calculation results fit well to experimental data in the literature. Then, the generation mechanisms of the third-order nonlinearity in SAW resonators are discussed. The dominant generation mechanisms for different nonlinear signals and the relation between electrode materials and H3 peak magnitude are revealed, which provides an important guideline for further nonlinear suppression.
Quantitative Analysis of Drag Force for Task-Specific Micromachine at Low Reynolds Numbers
Authors: Wang Qiang , Wang Zhen
Published: July 2022

Micromotors have spread widely in order to meet the needs of new applications, including cell operation, drug delivery, biosensing, precise surgery and environmental decontamination, due to their small size, low energy consumption and large propelling power, especially the newly designed multifunctional micromotors that combine many extra shape features in one device. Features such as rod-like receptors, dendritic biosensors and ball-like catalyzing enzymes are added to the outer surface of the tubular micromotor during fabrication to perform their special mission. However, the structural optimization of motion performance is still unclear. The main factor restricting the motion performance of the micromotors is the drag forces. The complex geometry of a micromotor makes its dynamic behavior more complicated in a fluid environment. This study aimed to design the optimum structure of tubular micromotors with minimum drag forces and obtain the magnitude of drag forces considering both the internal and external fluids of the micromotors. By using the computational fluid dynamics software Fluent 18.0 (ANSYS), the drag force and the drag coefficient of different conical micromotors were calculated. Moreover, the influence of the Reynolds numbers Re, the semi-cone angle δ and the ratios ξ and η on the drag coefficient was analyzed. The results show the drag force monotonically increased with Reynolds numbers Re and the ratio η. The extreme point of the drag curve is reached when the semi-cone angle δ is 8° and the ratio ξ is 3.846. This work provides theoretical support and guidance for optimizing the design and development of conical micromotors.
Laser Additive Manufacturing of Anti-Tetrachiral Endovascular Stents with Negative Poisson’s Ratio and Favorable Cytocompatibility
Authors: Chen Ke , Wan Haoran , Fang Xiang , Chen Hongyu
Published: July 2022

Laser additive manufacturing (LAM) of complex-shaped metallic components offers great potential for fabricating customized endovascular stents. In this study, anti-tetrachiral auxetic stents with negative Poisson ratios (NPR) were designed and fabricated via LAM. Poisson’s ratios of models with different diameters of circular node (DCN) were calculated using finite element analysis (FEA). The experimental method was conducted with the LAM-fabricated anti-tetrachiral stents to validate their NPR effect and the simulation results. The results show that, with the increase in DCN from 0.6 to 1.5 mm, the Poisson ratios of anti-tetrachiral stents varied from −1.03 to −1.12, which is in line with the simulation results. The interrelationship between structural parameters of anti-tetrachiral stents, their mechanical properties and biocompatibility was demonstrated. The anti-tetrachiral stents with a DCN of 0.9 mm showed the highest absolute value of negative Poisson’s ratio, combined with good cytocompatibility. The cytocompatibility tests indicate the envisaged cell viability and adhesion of the vascular endothelial cell on the LAM-fabricated anti-tetrachiral auxetic stents. The manufactured stents exhibit great superiority in the application of endovascular stent implantation due to their high flexibility for easy maneuverability during deployment and enough strength for arterial support.
Design, Fabrication, and Dynamic Environmental Test of a Piezoresistive Pressure Sensor
Authors: Gao Rui , Zhang Wenjun , Jing Junmin , Liao Zhiwei , Zhao Zhou , Yao Bin , Zhang Huiyu , Guo Yuzhen , Xu Yanbo , Wang Yonghua , Zhang Zengxing , Zhang Zhidong , Xue Chenyang
Published: July 2022

Microelectromechanical system (MEMS) pressure sensors have a wide range of applications based on the advantages of mature technology and easy integration. Among them, piezoresistive sensors have attracted great attention with the advantage of simple back-end processing circuits. However, less research has been reported on the performance of piezoresistive pressure sensors in dynamic environments, especially considering the vibrations and shocks frequently encountered during the application of the sensors. To address these issues, this paper proposes a design method for a MEMS piezoresistive pressure sensor, and the fabricated sensor is evaluated in a series of systematic dynamic environmental adaptability tests. After testing, the output sensitivity of the sensor chip was 9.21 mV∙bar−1, while the nonlinearity was 0.069% FSS. The sensor overreacts to rapidly changing pressure environments and can withstand acceleration shocks of up to 20× g. In addition, the sensor is capable of providing normal output over the vibration frequency range of 0–5000 Hz with a temperature coefficient sensitivity of −0.30% FSS °C−1 over the temperature range of 0–80 °C. Our proposed sensor can play a key role in applications with wide pressure ranges, high-frequency vibrations, and high acceleration shocks, as well as guide MEMS-based pressure sensors in high pressure ranges and complex environmental adaptability in their design.
Mineral Neutralizers as a Tool for Improving the Properties of Soil Contaminated with Copper
Authors: Żołnowski Andrzej Cezary , Wyszkowski Mirosław
Published: July 2022

In phytoremediation processes implemented in highly contaminated areas, there is a high risk of contaminant toxicity during the germination of freshly sown plants. In such conditions, it is recommended to support phytoremediation by using neutralizing additives. The present study aimed at assessing the effect of the addition of mineral neutralizers (MNs), i.e., limestone, clay, and zeolite, to soil contaminated with copper (0, 200, 400, 600 mg kg−1). Basic soil indicators were analyzed, such as pH, hydrolytic acidity (HAC), total exchangeable bases (TEB), cation exchange capacity (CEC), base saturation (BS), electrolytical conductivity (EC), total organic carbon (TOC), total nitrogen (Ntot), carbon to nitrogen ratio (C:N),, and interactions of soil micronutrients, such as Cu, Zn, Cd, Cr, Ni, Pb, Mn, and Fe with MNs. Copper contamination significantly decreased the soil pH and increased its HAC. A decrease in the share of TEB was found, which resulted in a decrease in the CEC and in BS of the soil. Among the additives, limestone had the most beneficial effect on reducing soil acidity, contributing to a significant increase in TEB, CEC, and BS. The least favorable effect was shown for clay, which generally caused the deterioration of soil properties. The MNs significantly increased the content of Zn, Cr, and Fe and lowered the content of Ni in the soil compared to the control. The demonstrated interactions indicate the diversified activity of MNs at different levels of soil contamination with copper.
Characterization and Toxicity Analysis of Lab-Created Respirable Coal Mine Dust from the Appalachians and Rocky Mountains Regions
Authors: Salinas Vanessa , Das Milton , Jacquez Quiteria , Camacho Alexandra , Zychowski Katherine , Hovingh Mark , Medina Alexander , Rubasinghege Gayan , Rezaee Mohammad , Baltrusaitis Jonas , Fairley Neal , Roghanchi Pedram
Published: July 2022

Coal mine workers are continuously exposed to respirable coal mine dust (RCMD) in workplaces, causing severe lung diseases. RCMD characteristics and their relations with dust toxicity need further research to understand the adverse exposure effects to RCMD. The geographic clustering of coal workers’ pneumoconiosis (CWP) suggests that RCMD in the Appalachian region may exhibit more toxicity than other geographic regions such as the Rocky Mountains. This study investigates the RCMD characteristics and toxicity based on geographic location. Dissolution experiments in simulated lung fluids (SLFs) and in vitro responses were conducted to determine the toxicity level of samples collected from five mines in the Rocky Mountains and Appalachian regions. Dust characteristics were investigated using Fourier-transform infrared spectroscopy, scanning electron microscopy, the BET method, total microwave digestion, X-ray diffraction, and X-ray photoelectron spectroscopy. Inductively coupled plasma mass spectrometry was conducted to determine the concentration of metals dissolved in the SLFs. Finer particle sizes and higher mineral and elemental contents were found in samples from the Appalachian regions. Si, Al, Fe, Cu, Sr, and Pb were found in dissolution experiments, but no trends were found indicating higher dissolutions in the Appalachian region. In vitro studies indicated a proinflammatory response in epithelial and macrophage cells, suggesting their possible participation in pneumoconiosis and lung diseases development.
Biological Risk Assessment of Three Dental Composite Materials following Gas Plasma Exposure
Authors: Bekeschus Sander , Miebach Lea , Pommerening Jonas , Clemen Ramona , Witzke Katharina
Published: July 2022

Gas plasma is an approved technology that generates a plethora of reactive oxygen species, which are actively applied for chronic wound healing. Its particular antimicrobial action has spurred interest in other medical fields, such as periodontitis in dentistry. Recent work has indicated the possibility of performing gas plasma-mediated biofilm removal on teeth. Teeth frequently contain restoration materials for filling cavities, e.g., resin-based composites. However, it is unknown if such materials are altered upon gas plasma exposure. To this end, we generated a new in-house workflow for three commonly used resin-based composites following gas plasma treatment and incubated the material with human HaCaT keratinocytes in vitro. Cytotoxicity was investigated by metabolic activity analysis, flow cytometry, and quantitative high-content fluorescence imaging. The inflammatory consequences were assessed using quantitative analysis of 13 different chemokines and cytokines in the culture supernatants. Hydrogen peroxide served as the control condition. A modest but significant cytotoxic effect was observed in the metabolic activity and viability after plasma treatment for all three composites. This was only partially treatment time-dependent and the composites alone affected the cells to some extent, as evident by differential secretion profiles of VEGF, for example. Gas plasma composite modification markedly elevated the secretion of IL6, IL8, IL18, and CCL2, with the latter showing the highest correlation with treatment time (Pearson’s r > 0.95). Cell culture media incubated with gas plasma-treated composite chips and added to cells thereafter could not replicate the effects, pointing to the potential that surface modifications elicited the findings. In conclusion, our data suggest that gas plasma treatment modifies composite material surfaces to a certain extent, leading to measurable but overall modest biological effects.
Composition of Pinot Noir Wine from Grapevine Red Blotch Disease-Infected Vines Managed with Exogenous Abscisic Acid Applications
Authors: Huang Ling , Alcazar Magana Armando , Skinkis Patricia A. , Osborne James , Qian Yanping L. , Qian Michael C.
Published: July 2022

Grapevine red blotch disease (GRBD) has negative effects on grape development and impacts berry ripening. Abscisic acid (ABA) is a plant growth regulator involved in the initiation of berry ripening. Exogenous abscisic acid application was compared to an unsprayed control on GRBD-positive Pinot noir vines during two vintages, and the total monomeric anthocyanin, total phenolics, phenolic composition, and volatile profile were measured in wines. In addition, untargeted metabolites were profiled using high-resolution LC-MS/MS. Results showed that the wine composition varied by vintage year and was not consistent with ABA application. Wines from the ABA treatment had a lower total anthocyanin and total phenolic content in one year. The untargeted high-resolution LC-MS/MS analysis showed a higher abundance of phenolic compounds in ABA wines in 2019, but lower in 2018. The wine volatile compounds of ABA treatments varied by vintage. There were higher levels of free β-damascenone, β-ionone, nerol, and several fermentation-derived esters, acids, and alcohols in ABA wines, but these were not observed in 2019. Lower 3-isobutyl-2-methoxypyrazine (IBMP) was also observed in wines with ABA treatment in 2019. The results demonstrated that ABA application to the fruit zones did not consistently mitigate the adverse impacts of GRBD on Pinot noir wines.
Removal of Carbamazepine in Aqueous Solution by CoS2/Fe2+/PMS Process
Authors: Wu Tingting , Peng Huan , Liu Xiaowei , Wu Ruijin
Published: July 2022

Carbamazepine (CBZ), as a typical pharmaceutical and personal care product (PPCP), cannot be efficiently removed by the conventional drinking water and wastewater treatment process. In this work, the CoS2/Fe2+/PMS process was applied for efficient elimination of CBZ. The CBZ removal efficiency of CoS2/Fe2+/PMS was 2.5 times and 23 times higher than that of CoS2/PMS and Fe2+/PMS, respectively. The intensity of DMPO-HO• and DMPO-SO4•− followed the order of Fe2+/PMS < CoS2/PMS < CoS2/Fe2+/PMS, also suggesting the CoS2/Fe2+/PMS process has the highest oxidation activity. The effects of reaction conditions (e.g., CoS2 dosage, Fe2+ concentration, PMS concentration, initial CBZ concentration, pH, temperature) and water quality parameters (e.g., SO42−, NO3−, H2PO4−, Cl−, NH4+, humic acid) on the degradation of CBZ were also studied. Response surface methodology analysis was carried out to obtain the best conditions for the removal of CBZ, which are: Fe2+ = 70 µmol/L, PMS = 240 µmol/L, CoS2 = 0.59 g/L. The sustainability test demonstrated that the repeated use of CoS2 for 8 successive cycles resulted in little function decrease (<10%). These findings suggest that CoS2/Fe2+/PMS may be a promising method for advanced treatment of tailwater from sewage treatment plant.
The Inhibitory Potential of 2′-dihalo Ribonucleotides against HCV: Molecular Docking, Molecular Simulations, MM-BPSA, and DFT Studies
Authors: Khalil Ahmed , El-Khouly Amany S. , Elkaeed Eslam B. , Eissa Ibrahim H.
Published: July 2022

Sofosbuvir is the first approved direct-acting antiviral (DAA) agent that inhibits the HCV NS5B polymerase, resulting in chain termination. The molecular models of the 2′-dihalo ribonucleotides used were based on experimental biological studies of HCV polymerase inhibitors. They were modeled within HCV GT1a and GT1b to understand the structure–activity relationship (SAR) and the binding interaction of the halogen atoms at the active site of NS5B polymerase using different computational approaches. The outputs of the molecular docking studies indicated the correct binding mode of the tested compounds against the active sites in target receptors, exhibiting good binding free energies. Interestingly, the change in the substitution at the ribose sugar was found to produce a mild effect on the binding mode. In detail, increasing the hydrophobicity of the substituted moieties resulted in a better binding affinity. Furthermore, in silico ADMET investigation implied the general drug likeness of the examined derivatives. Specifically, good oral absorptions, no BBB penetration, and no CYP4502D6 inhibitions were expected. Likely, the in silico toxicity studies against several animal models showed no carcinogenicity and high predicted TD50 values. The DFT studies exhibited a bioisosteric effect between the substituents at the 2′-position and the possible steric clash between 2′-substituted nucleoside analogs and the active site in the target enzyme. Finally, compound 6 was subjected to several molecular dynamics (MD) simulations and MM-PBSA studies to examine the protein-ligand dynamic and energetic stability.
Engineered 3D-Printed Polyvinyl Alcohol Scaffolds Incorporating β-Tricalcium Phosphate and Icariin Induce Bone Regeneration in Rat Skull Defect Model
Authors: Xu Zhimin , Sun Yidan , Dai Huanyan , Ma Yujie , Bing Han
Published: July 2022

The skull defects are challenging to self-heal, and autologous bone graft repair has numerous drawbacks. The scaffolds for the rapid and effective repair of skull defects have become an important research topic. In this study, polyvinyl alcohol (PVA)/β-tricalcium phosphate(β-TCP) composite scaffolds containing icariin (ICA) were prepared through direct-ink three-dimensional (3D) printing technology. β-TCP in the composite scaffold had osteoconductive capability, and the ICA molecule had osteoinductive capacity. The β-TCP and ICA components in the composite scaffold can enhance the capability to repair skull defects. We show that ICA exhibited a slow-release behaviour within 80 days. This behaviour helped the scaffold to continuously stimulate the formation of new bone. The results of in vitro cell compatibility experiments showed that the addition of ICA molecules contributed to the adhesion and proliferation of MC-3T3-E1 cells. The level of alkaline phosphatase secretion demonstrated that the slow release of ICA can promote the osteogenic differentiation of MC-3T3-E1 cells. The introduction of ICA molecules accelerated the in situ bone regeneration in in vivo. It is concluded that the 3D-printed PVA scaffold with β-TCP and ICA has a wide range of potential applications in the field of skull defect treatment.