bluuebunny/crossref_metadata_2025 huggingface dataset:
The Influence of Dry Hydrated Limes on the Fresh and Hardened Properties of Architectural Injection Grout
Authors: Padovnik Andreja , Bokan-Bosiljkov Violeta
Published: September 2021

Dry hydrated lime is an air binder often used in architectural injection grouts. This study compared the influences of three commercially available dry hydrated limes on the injection grouts’ workability and mechanical properties. The main differences between the limes were in their chemical and mineralogical composition and Blaine specific surface area. The grouts were composed of dry hydrated lime, finely ground limestone filler, water, and super plasticiser. Subsequent results obtained revealed that the Blaine specific surface area is not directly related to the fresh grout properties. Grain size distribution and shape of lime particles and their aggregates in the water suspension are key parameters influencing the following fresh grout properties: fluidity, injectability, the mixture’s stability, and water retention capacity. However, the lime injection grouts’ mechanical strengths were higher in relation to an increase in the content of portlandite and the Blaine specific surface area of the dry hydrate.
Evaluation of the Pullout Behavior of Pre-Bored Piles Embedded in Rock
Authors: Park Kyungho , Kim Daehyeon , Kim Gyudeok , Lee Wooyoul
Published: September 2021

The subject of this study is dry process caisson tube method cofferdam (hereinafter called C.T cofferdam). This C.T cofferdam is designed to use the skin friction of the drilled shaft embedded into the rock for stability of buoyancy. A pre-bored pile embedded in the bedrock was pulled out due to the buoyancy of the C.T cofferdam at the pier (hereinafter called P) 2 of the OO bridges under construction, to which this was applied. In this study, in order to solve this problem, the adhesion force applied with the concept of skin friction and the pre-bored pile of drilled shaft according to domestic and foreign design standards were identified; the on-site pull-out load test was used to calculate the pull-out force; and the skin friction of the drilled shaft and pre-bored pile embedded into the bedrock were compared and analyzed. In addition, the pull-out behavior of the pre-bored pile embedded in the bedrock was analyzed through numerical analysis. The adhesion strength tested in the lab was 881 kN for air curing of concrete and 542 kN for water curing of concrete, and the on-site pull-out test result was 399.7 kN. As a result of the numerical analysis, the material properties of the grout considering the site conditions used revealed that the displacement of the entire structure exceeded the allowable limit and was unstable. This appears to have lowered the adhesion strength due to construction issues such as ground complexity and both seawater and slime treatment, which were not expected at the time of design.
Effect of Heat Treatment on Microstructure and Selective Corrosion of LPBF-AlSi10Mg by Means of SKPFM and Exo-Electron Emission
Authors: Cabrini Marina , Lorenzi Sergio , Testa Cristian , Manfredi Diego , Lombardi Mariangela , Aversa Alberta , Andreatta Francesco , Fedrizzi Lorenzo , Dekhtyar Yuri , Sorokins Hermanis , Pastore Tommaso
Published: September 2021

The paper deals with the evolution of the microstructure of AlSi10Mg alloy obtained by laser powder bed fusion (LPBF), as a function of the post-processing heat treatment temperature. This was approached by complementary methods including FE-scanning electron microscopy, scanning Kelvin probe force microscopy and exo-electron emission techniques. The fast cooling rate of the LPBF process as compared to traditional casting produces a very fine microstructure with high mechanical properties and corrosion resistance. However, the LPBF-AlSi10Mg alloy can be susceptible to selective corrosion at the edge of the melt pools generated by the laser scan tracks. Post-process thermal treatments of the Al alloy induce a marked modification of the silicon network at melt pool edges, in particular at high temperature such as 400 °C. It was found that this is associated to a more homogeneous distribution of Volta potential. Analysis of exo-electron emission confirms the silicon diffusion during thermal treatment. The modification of the silicon network structure of the LPBF-AlSi10Mg during thermal treatment reduces the susceptibility to selective corrosion.
Does Preheating Resin Cements Affect Fracture Resistance of Lithium Disilicate and Zirconia Restorations?
Authors: Sakrana Amal Abdelsamad , Al-Zordk Walid , El-Sebaey Heba , Elsherbini Ahmed , Özcan Mutlu
Published: September 2021

This paper assesses the impact of preheating of adhesive cement on the fracture resistance of lithium disilicate and zirconia restorations. Methods: A total of 80 human maxillary premolar teeth were assigned into 8 groups (n = 10) according to material type (either lithium disilicate or zirconia) and type of resin cement (either LinkForce or Panavia SA) with preheating temperature at 54 °C or at room temperature (25 °C). Teeth were prepared and restored with either lithium disilicate or zirconia restorations. After cementation, specimens were thermal cycled (10,000 cycles, 5 °C/55 °C), then load cycled for 240,000 cycles (50 N). Each specimen was statically loaded until fracture and the load (N) at fracture was recorded, then the failure mode was detected. Statistical analysis of data was performed (p ≤ 0.05). Results: There was no significant difference (p = 0.978) in fracture mean values between LinkForce and Panavia SA. Statistically significant difference (p = 0.001) was revealed between fracture resistance of lithium disilicate restorations cemented with LinkForce at 25 °C and at 54 °C; however there was no significant difference (p = 0.92) between the fracture resistance of lithium disilicate restorations cemented with Panavia SA used at 25 °C and at 54 °C. Regarding the interaction between ceramic material, cement type, and cement preheating, there was no significant effect (p > 0.05) in fracture resistance. The cement type does not influence the fracture resistance of ceramic restorations. Preheating of resin cement has negatively influenced the fracture resistance of all tested groups, except for lithium disilicate cemented using LinkForce cement.
Effect of Rare-Earth Ions on the Optical and PL Properties of Novel Borosilicate Glass Developed from Agricultural Waste
Authors: Alhodaib Aiyeshah , Ibrahim Omnia , Abd El All Suzy , Ezzeldin Fatthy
Published: September 2021

There is considerable attention devoted to the use of agricultural waste as a raw material substitute for commercial silica in the development of borosilicate glasses doped with rare earth oxides. Here, we present a novel structure for borosilicate glasses made from rice husk ash with a 25% molar ratio of extracted SiO2 and doped with neodymium (GRN) or dysprosium (GRD). Adding rare earth oxides to borosilicate glasses by the melt quenching method enhanced optical transmission due to the presence of their tetrahedral geometries. GRN samples showed few bands near zero, which constitutes good utility for band rejection filters in image devices, and the samples exhibited energy values ranging from 3.03 to 3.00 eV before and after gamma irradiation. Optical transmissions of GRD samples showed peaks at 25,974, 22,172, 13,333, 11,273, 9302, 7987, and 6042 cm−1. Deterioration in transmittance was observed when the investigated samples were exposed to irradiation doses of 20 and 50 kGy in the wavenumber range of 12,500 to 50,000 cm−1; however, different behaviors after irradiation with 50 kGy caused an increase in transparency in comparison to 20 kGy irradiation, which was pronounced for higher wavenumbers (greater than 12,500 cm−1). Photoluminescence emission and excitation spectra of the glass-doped Nd3+ (GRN) and glass-doped Dy3+ (GRD) samples were determined. GRD exhibited emission in the blue and yellow regions of the visible spectrum, which gave a white flash of light. Chromaticity coordinate (CIE) measurements of GRD samples indicated the origin of its luminous color relative to the standard white light region.
The Development of Filler Morphology in Dental Resin Composites: A Review
Authors: Liu Jiani , Zhang Hao , Sun Huijun , Liu Yanru , Liu Wenlin , Su Bo , Li Shibao
Published: September 2021

Dental resin composites (DRCs) with diverse fillers added are widely-used restorative materials to repair tooth defects. The addition of fillers brings an improvement in the mechanical properties of DRCs. In the past decade, diverse fillers have emerged. However, the change of emerging fillers mainly focuses on the chemical composition, while the morphologic characteristics changes are often ignored. The fillers with new morphologies not only have the advantages of traditional fillers (particles, fibrous filler, etc.), but also endow some additional functional characteristics (stronger bonding ability to resin matrix, polymerization resistance, and wear resistance, drug release control ability, etc.). Moreover, some new morphologies are closely related to the improvement of traditional fillers, porous filler vs. glass particles, core-sheath fibrous vs. fibrous, etc. Some other new morphology fillers are combinations of traditional fillers, UHA vs. HA particles and fibrous, tetrapod-like whisker vs. whisker and fibrous filler, mesoporous silica vs. porous and silica particles. In this review, we give an overall description and a preliminary summary of the fillers, as well as our perspectives on the future direction of the development of novel fillers for next-generation DRCs.
Anisotropic Mechanical Response and Strain Localization of a Metallic Glassy-Fiber-Reinforced Polyethylene Terephthalate Fabric
Authors: Li Jie , Huang Bo , Shen Jun , Yi Jun , Jia Yandong , Xue Rongjie , Wang Gang
Published: September 2021

Optimizing the mechanical properties of composites through microstructural design has been a long-standing issue in materials science. In this study, we reinforced a typical polymer, i.e., polyethylene-terephthalate-woven fabric, with a type of Fe-based metallic glassy fiber (MGF) with an extremely large Young’s moduli. The MGF-reinforced fabrics, with three different fiber bundle orientations (0°, 45°, and 90°), were investigated by in situ electron-microscopy mechanical testing techniques in conjunction with a digital image correlation (DIC) technique. The fabrics exhibited a pronounced anisotropic mechanical response, and the associated characteristics were verified to depend on the fiber bundle orientation relative to the external load. Furthermore, localized strains near the intersections of the fiber bundles were found to be much higher than the global strain. It is confirmed that the restriction from warp to weft is the dominant factor influencing strain localization during deformation. Our results are enlightening for understanding the fracture mechanisms of composites.
Classification of Design Methodologies to Minimize Vibrations in Gears and Bearings in the 21st Century: A Review
Authors: Tuirán Villalba Rafael , Maury Ramírez Heriberto , Águila Estrada Héctor
Published: September 2021

Associated vibrations in mechanical power transmission elements such as gears and bearings significantly contribute to the dynamic behavior of the system to which they belong. Most research in this field describes measurements and signal processing methods to determine the effect of some design modifications. However, the number of investigations that try to solve the problem from the design stage is much smaller. The following study presents a review of the trends in the analysis of vibrations of power transmission elements and their relationship to the use of systematic design methodologies in the principal power transmission elements. A revision is shown in design considerations to prevent mechanical vibrations or reduce them to acceptable levels. The effects in terms of improvement in reducing vibrations of the most important works that have taken into account the vibrations in design stages are shown. The results show the importance of considering the mechanical vibrations in the design of power transmission elements. Moreover, the analysis of the state of the art shows the areas to be investigated that contemplate the development or application of formal design methodologies that take into account mechanical vibrations.
Finite-Time Output Feedback Control for Electro-Hydraulic Servo Systems with Parameter Adaptation
Authors: Yin Luyue , Deng Wenxiang , Yang Xiaowei , Yao Jianyong
Published: September 2021

Measurement noise, parametric uncertainties, and external disturbances broadly exist in electro-hydraulic servo systems, which terribly deteriorate the system control performance. To figure out this problem, a novel finite-time output feedback controller with parameter adaptation is proposed for electro-hydraulic servo systems in this paper. First, to avoid using noise-polluted signals and attain active disturbance compensation, a finite-time state observer is adopted to estimate unknown system states and disturbances, which attenuates the impact of measurement noise and external disturbances on tracking performance. Second, by adopting a parameter adaptive law, the parametric uncertainties in the electro-hydraulic servo system can be much lessened, which is beneficial to averting the high-gain feedback in practice. Then, integrating the backstepping framework and the super-twisting sliding mode technique, a synthesized output feedback controller is constructed to achieve high-accuracy tracking performance for electro-hydraulic servo systems. Lyapunov stability analysis demonstrates that the proposed control scheme can acquire finite-time stability. The excellent tracking performance of the designed control law is verified by comparative simulation results.
Existence and Uniqueness of Nontrivial Periodic Solutions to a Discrete Switching Model
Authors: Chang Lijie , Shi Yantao , Zheng Bo
Published: September 2021

To control the spread of mosquito-borne diseases, one goal of the World Mosquito Program’s Wolbachia release method is to replace wild vector mosquitoes with Wolbachia-infected ones, whose capability of transmitting diseases has been greatly reduced owing to the Wolbachia infection. In this paper, we propose a discrete switching model which characterizes a release strategy including an impulsive and periodic release, where Wolbachia-infected males are released with the release ratio α1 during the first N generations, and the release ratio is α2 from the (N+1)-th generation to the T-th generation. Sufficient conditions on the release ratios α1 and α2 are obtained to guarantee the existence and uniqueness of nontrivial periodic solutions to the discrete switching model. We aim to provide new methods to count the exact numbers of periodic solutions to discrete switching models.
Adapting Hidden Naive Bayes for Text Classification
Authors: Gan Shengfeng , Shao Shiqi , Chen Long , Yu Liangjun , Jiang Liangxiao
Published: September 2021

Due to its simplicity, efficiency, and effectiveness, multinomial naive Bayes (MNB) has been widely used for text classification. As in naive Bayes (NB), its assumption of the conditional independence of features is often violated and, therefore, reduces its classification performance. Of the numerous approaches to alleviating its assumption of the conditional independence of features, structure extension has attracted less attention from researchers. To the best of our knowledge, only structure-extended MNB (SEMNB) has been proposed so far. SEMNB averages all weighted super-parent one-dependence multinomial estimators; therefore, it is an ensemble learning model. In this paper, we propose a single model called hidden MNB (HMNB) by adapting the well-known hidden NB (HNB). HMNB creates a hidden parent for each feature, which synthesizes all the other qualified features’ influences. For HMNB to learn, we propose a simple but effective learning algorithm without incurring a high-computational-complexity structure-learning process. Our improved idea can also be used to improve complement NB (CNB) and the one-versus-all-but-one model (OVA), and the resulting models are simply denoted as HCNB and HOVA, respectively. The extensive experiments on eleven benchmark text classification datasets validate the effectiveness of HMNB, HCNB, and HOVA.
Automatic Superpixel-Based Clustering for Color Image Segmentation Using q-Generalized Pareto Distribution under Linear Normalization and Hunger Games Search
Authors: Abd Elaziz Mohamed , Abo Zaid Esraa Osama , Al-qaness Mohammed A. A. , Ibrahim Rehab Ali
Published: September 2021

Superixel is one of the most efficient of the image segmentation approaches that are widely used for different applications. In this paper, we developed an image segmentation based on superpixel and an automatic clustering using q-Generalized Pareto distribution under linear normalization (q-GPDL), called ASCQPHGS. The proposed method uses the superpixel algorithm to segment the given image, then the Density Peaks clustering (DPC) is employed to the results obtained from the superpixel algorithm to produce a decision graph. The Hunger games search (HGS) algorithm is employed as a clustering method to segment the image. The proposed method is evaluated using two different datasets, collected form Berkeley segmentation dataset and benchmark (BSDS500) and standford background dataset (SBD). More so, the proposed method is compared to several methods to verify its performance and efficiency. Overall, the proposed method showed significant performance and it outperformed all compared methods using well-known performance metrics.
Global Food Security, Economic and Health Risk Assessment of the COVID-19 Epidemic
Authors: Kovács Sándor , Rabbi Mohammad Fazle , Máté Domicián
Published: September 2021

This study addresses the complexity of global pandemic (COVID) exposures and explores how sustainable development relates to economic and health risks and food security. Multiple factor analysis (MFA) is applied to compute the links among blocks of variables, and results are validated by random sampling with bootstrapping, exhaustive and split-half techniques, and analysis of variance (ANOVA) to test the differences of the MFA factors within the different stages of competitiveness. Comparing the MFA factors suggests that higher competitiveness is correlated with better food security and natural resilience and the tremendous economic downturn; the most competitive countries have lower exposures to health risks. In addition, the risk of pandemics appears to be lower with well-established public health care (HC) system services and good health for the population. The study also underlines that the economic and health systems are unfortunately inadequate to deal with a crisis of this magnitude. Although the countries least affected by the epidemic are the most competitive, they cannot protect people and the economy effectively. Formulating appropriate global responses is a challenge, but the results may lead to more nuanced findings regarding treatment policies that can be addressed at the country level.
Blood Clotting Decreases Pulmonary Circulation during the Coronavirus Disease
Authors: Mozokhina Anastasia , Bouchnita Anass , Volpert Vitaly
Published: September 2021

Spontaneous blood clotting in pulmonary circulation caused by thrombo-inflammation is one of the main mortality causes during the COVID-19 disease. Blood clotting leads to reduced pulmonary circulation and blood oxygenation. Lung inflammation can be evaluated with noninvasive diagnostic techniques. However, the correlation of the severity of the inflammation with the pulmonary blood flow has not been established. To address this question, in this work, we develop a multiscale model taking into account the interaction of a local model of thrombus growth with 1D hemodynamics in a vessel network. Flux reduction depending on the level of lung obstruction is evaluated. In particular, the model obtains that an obstruction level of 5% leads to a 12% reduction of blood flux. The suggested approach can be used to investigate the interaction of blood clotting and flow not only in the pulmonary network but also in other complex vessel networks.
Association between β2-Adrenoreceptor Medications and Risk of Parkinson’s Disease: A Meta-Analysis
Authors: Chen Chu-Ling , Wang Shu-Yi , Chen Ta-Cheng , Chuang Chieh-Sen
Published: September 2021

Background and Objective: Parkinson’s disease (PD) is a progressive neurological disorder characterized by an accumulation of Lewy bodies and degeneration of dopaminergic neurons in the substantia nigra. The treatment options currently available are only partly effective and fail to restore the lost dopaminergic neurons or slow the progression. β2-adrenoceptors (β2AR) are widely expressed in various human tissues and organs, regulate many important metabolic functions, and are targeted for treatment of various diseases. Studies have reported a link between chronic use of the β2AR antagonist propranolol and an increased risk of PD, and chronic use of β2AR agonists has been associated with a decreased risk of PD. We conducted a meta-analysis on the association between both β2AR agonist level and β2AR antagonist level and the risk of PD. Materials and Methods: A comprehensive electronic search was conducted on the databases of PubMed, ScienceDirect, ProQuest, Cochrane Library, and ClinicalKey from the start of each database until 30 June 2021. The objective was to identify prospective cohort and case–control studies that have reported on the association between β-adrenoceptor agonist level, antagonist level, and PD risk. Results: A meta-analysis of the data extracted from eight studies revealed that β2AR agonist use was associated with reduced PD risk (RR = 0.859, 95% confidence interval [CI] 0.741–0.995. p = 0.043). Compared with the control group, β2AR antagonist use was associated with an increased risk of PD (RR = 1.490, 95% CI, 1.195 to 1.857. p < 0.005). Propranolol, a type of β2AR antagonist, was related to an increased risk of PD (RR = 2.820, 95% CI, 2.618 to 3.036. p < 0.005). Conclusions: In this meta-analysis, β2AR agonists were associated with a decreased risk of PD, and β2AR antagonists were related with an increased risk of PD. However, further studies with larger sample sizes and an evaluation of the long-term effects of varying dosages of medications are needed.
Myopathy Associated with Treatment of Graves’ Disease
Authors: Ji Yoon-Kyung , Kim Shin-Hee
Published: September 2021

Here, we report a case of an increase in serum creatine kinase (CK) concentration in an 11-year-old girl being treated for Graves’ disease with antithyroid drugs (ATDs). The patient complained of myalgia two weeks after methimazole treatment. Triiodothyronine (T3) and free thyroxine (FT4) levels were normal, but the serum CK level was significantly elevated. After switching to propylthiouracil, the serum CK level decreased to normal, and the myalgia was resolved. The development of myopathy during the treatment of hyperthyroidism may be considered as an adverse reaction of MMI. In this report, we present a rare pediatric case, along with a discussion on the possible causes of myopathy that occurred during the treatment of Graves’ disease. A careful follow-up (serum CK levels and thyroid function) and treatment reassessment should always be considered after antithyroid treatment.
Effects of Antithrombotic Agents on Ophthalmological Outcomes, Cardiovascular Risk, and Mortality in Hypertensive Patients with Retinal Vein Occlusion: An Exploratory Retrospective Study
Authors: Bertoli Federica , Bais Bruno , De Silvestri Daniele , Mariotti Barbara , Veritti Daniele , Cavarape Alessandro , Catena Cristiana , Lanzetta Paolo , Sechi Leonardo Alberto , Colussi GianLuca
Published: September 2021

Background and objectives: Because few data are available, the aim of this study is to analyze the effects of antithrombotic agents (ATAs) on visual function and long-term risk of cardiovascular events and mortality in hypertensive patients with retinal vein occlusion (RVO). Materials and methods: Hypertensive patients with RVO were consecutively selected from 2008 to 2012 and followed for a median of 8.7 years. Ophthalmologists evaluated and treated RVO complications, and best-corrected visual acuity (BCVA) was checked at each visit during the first one year of follow-up. Survival analysis was conducted on the rate of the composite endpoint of all-cause deaths or non-fatal cardiovascular events. Results: Retrospectively, we collected data from 80 patients (age 68 ± 12 years, 39 males). Central and branch RVO was present in 41 and 39 patients, respectively, and 56 patients started ATAs (50 antiplatelet drugs, 6 warfarin, and 2 low-molecular weight heparin). Average BCVA of the cohort did not change significantly during one-year of follow-up. The only predictor of BCVA was the baseline BCVA value. There was a reduction in proportion and severity of macular edema and an increase in the cumulative proportion of retinal vein patency reestablishment during the follow-up, independent of treatment. ATAs had no effects on one-year BCVA, intraocular complications, or the composite endpoint rate. Conclusions: In this exploratory study, ATAs had no effect on BCVA during the first one year of follow-up and on the composite endpoint during the long-term follow-up. Further prospective studies need to be conducted with an accurate standardization of the intraocular and antithrombotic treatment to define the positive or negative role of ATAs in hypertensive patients with RVO.
EUS and ERCP in the Same Session for Biliary Stones: From Risk Stratification to Treatment Strategy in Different Clinical Conditions
Authors: Fusaroli Pietro , Lisotti Andrea
Published: September 2021

Endoscopic retrograde cholangiopancreatography (ERCP) with sphincterotomy and stone extraction is the treatment of choice for choledocholithiasis, reaching a successful clearance of the common bile duct (CBD) in up to 90% of the cases. Endoscopic ultrasound (EUS) has the best diagnostic accuracy for CBD stones, its sensitivity and specificity range being 89–94% and 94–95%, respectively. Traditionally seen as two separate entities, the two worlds of EUS and ERCP have recently come together under the new discipline of bilio-pancreatic endoscopy. Nevertheless, the complexity of both EUS and ERCP led the European Society of Gastrointestinal Endoscopy to identify quality in endoscopy as a top priority in its recent EUS and ERCP curriculum recommendations. The clinical benefits of performing EUS and ERCP in the same session are several, such as benefiting from real-time information from EUS, having one single sedation for both the diagnosis and the treatment of biliary stones, reducing the risk of cholangitis/acute pancreatitis while waiting for ERCP after the EUS diagnosis, and ultimately shortening the hospital stay and costs while preserving patients’ outcomes. Potential candidates for the same session approach include patients at high risk for CBD stones, symptomatic individuals with status post-cholecystectomy, pregnant women, and those unfit for surgery. This narrative review discusses the main technical aspects and evidence from the literature about EUS and ERCP in the management of choledocholithiasis.
The Relation of Body Mass Index to Muscular Viscoelastic Properties in Normal and Overweight Individuals
Authors: Usgu Serkan , Ramazanoğlu Engin , Yakut Yavuz
Published: September 2021

Background: The body mass index (BMI) is closely related to fat tissue, which may have direct or indirect effects on muscle function. Previous studies have evaluated BMI and muscle viscoelastic properties in vivo in older people or individual sexes; however, the relationship between BMI and muscular viscoelastic properties is still unknown. Aims: The purpose of this study was to determine the correlation of BMI with muscular viscoelastic properties, and to compare these properties in a young sedentary population with normal and overweight individuals. Methods: A total of 172 healthy sedentary individuals (mean age, 26.00 ± 5.45 years) were categorized by sex (male and female) and BMI classification (normal (BMI, 18.50–24.99 kg/m2), overweight (BMI = 25.00–29.99 kg/m2)). Body weight was evaluated using an electronic scale, while height was measured using a standard stadiometer. BMI was calculated by dividing the weight in kilograms by the square of height in meters. The viscoelastic properties (tone, stiffness, and elasticity) of the biceps brachii (BB) and biceps femoris (BF) muscles were measured bilaterally using the MyotonPRO device at rest. Results: The bilateral BF tone and stiffness, right BB stiffness, and elasticity showed weak correlations with BMI in all participants. Furthermore, the bilateral BF tone and stiffness, right BB stiffness and elasticity, and left BB stiffness were weakly positively correlated with male sex. Only the right BB elasticity was weakly positively correlated with BMI in females (p < 0.05). No correlation with BMI was determined for other viscoelastic properties (p > 0.05). The overweight group showed increased bilateral BF stiffness and tone, right BB stiffness, and reduced bilateral BB elasticity compared to the normal-weight group (p < 0.05), while other viscoelastic properties were similar (p > 0.05). Greater bilateral BB tone, BF tone and stiffness, and lower BF elasticity were observed in males than in females (p < 0.05), but other viscoelastic properties were not significantly different (p < 0.05). No effect of BMI–sex interactions was found on viscoelastic properties (p > 0.05). Conclusions: The BB and BF viscoelastic properties were weakly correlated with BMI. Males showed greater muscle tone and stiffness, and lower elasticity. The overweight individuals showed increased stiffness and tone, particularly in lower extremities, and reduced elasticity in upper extremities. The effect of BMI–sex interactions on the viscoelastic properties was not clear. Higher BMI (increased mechanical load) might cause the human body to develop different muscular viscoelastic adaptations in the extremities.
Extramammary Paget’s Disease of the Vulva: Report of Two Cases
Authors: Kosmidis Christoforos S. , Sevva Christina , Roulia Panagiota , Koulouris Charilaos , Varsamis Nikolaos , Koimtzis Georgios , Theodorou Vasiliki , Mystakidou Chrysi Maria , Georgakoudi Eleni , Anthimidis Georgios
Published: September 2021

Extramammary Paget’s disease is a rare condition, affecting 6.5% of all patients with Paget’s disease. The most common extramammary site is the vulvar area. Although diagnosis in some patients is difficult to set, early diagnosis is of high importance in order to detect the irreversible progression of the lesion early and prevent distant metastasis. An 89-year-old female and a 69-year-old female presented within three months with an eczematous lesion with leukoplakia in the vulva. The incisional biopsy of the skin revealed extramammary Paget’s disease. Both patients underwent a surgical wide local excision of the lesion and the specimens were sent for histopathological examination. Extramammary Paget’s disease has a high potential for distant malignancies and local recurrence, dictating that surgical excision is the most efficient treatment. The rareness of the condition and the diagnostic difficulties underline the need for early skin biopsy, which is the most efficient diagnostic tool.
Tissue-Engineered Vascular Graft with Co-Culture of Smooth Muscle Cells and Human Endothelial Vein Cells on an Electrospun Poly(lactic-co-glycolic acid) Microtube Array Membrane
Authors: Chew Chee Ho , Sheu Bo-Long , Chen Amanda , Huang Wan-Ting , Cheng Tsai-Mu , Shih Chun-Ming , Chang Austin , Chen Chien-Chung
Published: September 2021

Coronary artery disease is one of the major diseases that plagues today’s modern society. Conventional treatments utilize synthetic vascular grafts such as Dacron® and Teflon® in bypass graft surgery. Despite the wide adaptation, these synthetic grafts are often plagued with weaknesses such as low hemocompatibility, thrombosis, intimal hyperplasia, and risks of graft infection. More importantly, these synthetic grafts are not available at diameters of less than 6 mm. In view of these challenges, we strived to develop and adapt the electrospun Poly Lactic-co-Glycolic Acid (PLGA) Microtube Array Membrane (MTAM) vascular graft for applications smaller than 6 mm in diameter. Homogenously porous PLGA MTAMs were successfully electrospun at 5.5–8.5 kV under ambient conditions. Mechanically, the PLGA MTAMs registered a maximum tensile strength of 5.57 ± 0.85 MPa and Young’s modulus value of 1.134 ± 0.01 MPa; while MTT assay revealed that seven-day Smooth Muscle Cells (SMCs) and Human Umbilical Vein Endothelial Cells (HUVECs) registered a 6 times and 2.4 times higher cell viability when cultured in a co-culture setting in medium containing α-1 haptaglobulin. When rolled into a vascular graft, the PLGA MTAMs registered an overall degradation of 82% after 60 days of cell co-culture. After eight weeks of culturing, immunohistochemistry staining revealed the formation of a monolayer of HUVECs with tight junctions on the surface of the PLGA MTAM, and as for the SMCs housed within the lumens of the PLGA MTAMs, a monolayer with high degree of orientation was observed. The PLGA MTAM registered a burst pressure of 1092.2 ± 175.3 mmHg, which was sufficient for applications such as small diameter blood vessels. Potentially, the PLGA MTAM could be used as a suitable substrate for vascular engineering.
Features of Thermomechanical Stability of Anionic–Cation Exchange Matrix “Polikon AC” on Viscose Non-Woven Materials
Authors: Terin Denis , Kardash Marina , Korchagin Sergey , Tsyplyayev Sergey , Cherkasov Vladimir , Druzhinina Tamara
Published: September 2021

The thermomechanical stability of the anion–cation exchange matrix “Polikon AC” on viscose nonwoven materials is investigated. In this work, a molecular model of a solvation environment for experimentally obtained “Polikon AC” mosaic membranes is refined. Mosaic membranes on a viscose fiber base were fabricated by the method of polycondensation filling. The temperature dependence of deformation was investigated for dry and wet anion and cation exchange membrane components at a constant tensile load of 1.5 N and a heating rate of 8 °C/min. The effect of moisture content on the deformation of anionite and cationite fragments under a constant external tensile load of 1.5 and 3 N in a temperature range up to 100 °C was studied.
Powder Metallurgy: A New Open Section in Metals
Authors: Torralba Jose Manuel
Published: September 2021

Powder Metallurgy (PM) is a forming technology that uses metallic (sometimes also in conjunction with ceramic) powders to develop parts, most of the time through a thermal process called sintering, which never reaches the melting point of the principal component of the alloy [...]
Hot Deformation Behavior of Novel Al-Cu-Y(Er)-Mg-Mn-Zr Alloys
Authors: Khomutov Maxim G. , Amer Sayed M. , Barkov Ruslan Yu. , Glavatskikh Maria V. , Churyumov Alexander Yu. , Pozdniakov Andrey V.
Published: September 2021

The compression tests in a temperature range of 400–540 °C and strain rates of 0.1–15 s−1 were applied to novel Al-Cu-Y(Er)-Mg-Mn-Zr alloys to investigate their hot deformation behavior. The higher volume fraction of the intermetallic particles with a size of 0.5–4 µm in the alloys caused an increase in flow stress. Hyperbolic sine law constitutive models were constructed for the hot deformation behavior of Al-Cu-Y(Er)-Mg-Mn-Zr alloys. Effective activation energy has a higher value in the alloys with Er than in the alloys with Y. According to the processing maps, the temperature range of 420–480 °C and strain rates higher than 5 s−1 are the most unfavorable region for hot deformation for the investigated alloys. The deformation at 440 °C and 15 s−1 led to cracks on the surface of the sample. However, internal cracks were not observed in the microstructure after deformation. The optimum hot deformation temperatures were in a range of 500–540 °C and at strain rates of 0.1–15 s−1.
Optimizing the High-Performance Milling of Thin Aluminum Alloy Plates Using the Taguchi Method
Authors: Kuo Cheng-Hsien , Lin Zi-Yi
Published: September 2021

Most aerospace parts are thin walled and made of aluminum or titanium alloy that is machined to the required shape and dimensions. Deformation is a common issue. Although the reduced cutting forces used in high-speed milling generate low residual stress, the problem of deformation cannot be completely resolved. In this work, we emphasized that choosing the correct cutting parameters and machining techniques could increase the cutting performance and surface quality and reduce the deformation of thin plates. In this study, a part made of a thin 6061 aluminum alloy plate was machined by high-speed milling (HSM), and a Taguchi L16 orthogonal array was used to optimize the following parameters: linear velocity, feed per tooth, cutting depth, cutting width, and toolpath. The impact of cutting parameters on the degree of deformation, surface roughness, as well as the cutting force on the thin plate were all investigated. The results showed that the experimental parameters for the optimal degree of deformation were A1 (linear velocity 450 mm/min), B1 (feed per tooth 0.06 mm/tooth), C1 (cutting depth 0.3 mm), D4 (cutting width 70%), and E4 (rough zigzag). Feed per tooth was the most significant control factor, with a contribution as high as 63.5%. It should also be mentioned that, according to the factor response of deformation, there was a lower value of feed per tooth and less deformation. Furthermore, the feed per tooth and the cutting depth decreased and the surface roughness increased. The cutting force rose or fell with an increase or decrease of cutting depth.
Comparison of Properties and Bead Geometry in MIG and CMT Single Layer Samples for WAAM Applications
Authors: Stinson Harley , Ward Richard , Quinn Justin , McGarrigle Cormac
Published: September 2021

The process of Wire Arc Additive Manufacturing (WAAM) utilizes arc welding technology to fabricate metallic components by depositing material in a selective layered fashion. Several welding processes exist that can achieve this layered deposition strategy. Gas Metal Arc Welding (GMAW) derived processes are commonly favored for their high deposition rates (1–4 kg/h) and minimal torch reorientation required during deposition. A range of GMAW processes are available; all of which have different material transfer modes and thermal energy input ranges and the resultant metallic structures formed from these processes can vary in their mechanical properties and morphology. This work will investigate single-layer deposition and vary the process parameters and process mode to observe responses in mechanical properties, bead geometry and deposition rate. The process modes selected for this study were GMAW derived process of Metal Inert Gas (MIG) and Cold Metal Transfer (CMT). Characterization of parameter sets revealed relationships between torch travel speeds, wire feed speeds and the specimen properties and proportions. Differences were observed in the cross-sectional bead geometry and deposition rates when comparing MIG and CMT samples though the influence of process mode on mechanical properties was less significant compared to process parameter selection.
Physiological and Pathological Roles of Aldose Reductase
Authors: Singh Mahavir , Kapoor Aniruddh , Bhatnagar Aruni
Published: September 2021

Aldose reductase (AR) is an aldo-keto reductase that catalyzes the first step in the polyol pathway which converts glucose to sorbitol. Under normal glucose homeostasis the pathway represents a minor route of glucose metabolism that operates in parallel with glycolysis. However, during hyperglycemia the flux of glucose via the polyol pathway increases significantly, leading to excessive formation of sorbitol. The polyol pathway-driven accumulation of osmotically active sorbitol has been implicated in the development of secondary diabetic complications such as retinopathy, nephropathy, and neuropathy. Based on the notion that inhibition of AR could prevent these complications a range of AR inhibitors have been developed and tested; however, their clinical efficacy has been found to be marginal at best. Moreover, recent work has shown that AR participates in the detoxification of aldehydes that are derived from lipid peroxidation and their glutathione conjugates. Although in some contexts this antioxidant function of AR helps protect against tissue injury and dysfunction, the metabolic transformation of the glutathione conjugates of lipid peroxidation-derived aldehydes could also lead to the generation of reactive metabolites that can stimulate mitogenic or inflammatory signaling events. Thus, inhibition of AR could have both salutary and injurious outcomes. Nevertheless, accumulating evidence suggests that inhibition of AR could modify the effects of cardiovascular disease, asthma, neuropathy, sepsis, and cancer; therefore, additional work is required to selectively target AR inhibitors to specific disease states. Despite past challenges, we opine that a more gainful consideration of therapeutic modulation of AR activity awaits clearer identification of the specific role(s) of the AR enzyme in health and disease.
The Fusion of Microfluidics and Optics for On-Chip Detection and Characterization of Microalgae
Authors: Zheng Xinqi , Duan Xiudong , Tu Xin , Jiang Shulan , Song Chaolong
Published: September 2021

It has been demonstrated that microalgae play an important role in the food, agriculture and medicine industries. Additionally, the identification and counting of the microalgae are also a critical step in evaluating water quality, and some lipid-rich microalgae species even have the potential to be an alternative to fossil fuels. However, current technologies for the detection and analysis of microalgae are costly, labor-intensive, time-consuming and throughput limited. In the past few years, microfluidic chips integrating optical components have emerged as powerful tools that can be used for the analysis of microalgae with high specificity, sensitivity and throughput. In this paper, we review recent optofluidic lab-on-chip systems and techniques used for microalgal detection and characterization. We introduce three optofluidic technologies that are based on fluorescence, Raman spectroscopy and imaging-based flow cytometry, each of which can achieve the determination of cell viability, lipid content, metabolic heterogeneity and counting. We analyze and summarize the merits and drawbacks of these micro-systems and conclude the direction of the future development of the optofluidic platforms applied in microalgal research.
6S-Like scr3559 RNA Affects Development and Antibiotic Production in Streptomyces coelicolor
Authors: Bobek Jan , Mikulová Adéla , Šetinová Dita , Elliot Marie , Čihák Matouš
Published: September 2021

Regulatory RNAs control a number of physiological processes in bacterial cells. Here we report on a 6S-like RNA transcript (scr3559) that affects both development and antibiotic production in Streptomyces coelicolor. Its expression is enhanced during the transition to stationary phase. Strains that over-expressed the scr3559 gene region exhibited a shortened exponential growth phase in comparison with a control strain; accelerated aerial mycelium formation and spore maturation; alongside an elevated production of actinorhodin and undecylprodigiosin. These observations were supported by LC-MS analyses of other produced metabolites, including: germicidins, desferrioxamines, and coelimycin. A subsequent microarray differential analysis revealed increased expression of genes associated with the described morphological and physiological changes. Structural and functional similarities between the scr3559 transcript and 6S RNA, and its possible employment in regulating secondary metabolite production are discussed.
Low Resistance Asymmetric III-Nitride Tunnel Junctions Designed by Machine Learning
Authors: Lin Rongyu , Han Peng , Wang Yue , Lin Ronghui , Lu Yi , Liu Zhiyuan , Zhang Xiangliang , Li Xiaohang
Published: September 2021

The tunnel junction (TJ) is a crucial structure for numerous III-nitride devices. A fundamental challenge for TJ design is to minimize the TJ resistance at high current densities. In this work, we propose the asymmetric p-AlGaN/i-InGaN/n-AlGaN TJ structure for the first time. P-AlGaN/i-InGaN/n-AlGaN TJs were simulated with different Al or In compositions and different InGaN layer thicknesses using TCAD (Technology Computer-Aided Design) software. Trained by these data, we constructed a highly efficient model for TJ resistance prediction using machine learning. The model constructs a tool for real-time prediction of the TJ resistance, and the resistances for 22,254 different TJ structures were predicted. Based on our TJ predictions, the asymmetric TJ structure (p-Al0.7Ga0.3N/i-In0.2Ga0.8N/n-Al0.3Ga0.7N) with higher Al composition in p-layer has seven times lower TJ resistance compared to the prevailing symmetric p-Al0.3Ga0.7N/i-In0.2Ga0.8N/n-Al0.3Ga0.7N TJ. This study paves a new way in III-nitride TJ design for optical and electronic devices.
Impacts of Surface Hydrophilicity of Carboxylated Polyethersulfone Supports on the Characteristics and Permselectivity of PA-TFC Nanofiltration Membranes
Authors: Lian Yingfu , Zhang Gang , Wang Xiaojun , Yang Jie
Published: September 2021

Our current study experimentally evaluates the impacts of surface hydrophilicity of supports on the properties of polyamide (PA) thin-film composite (TFC) nanofiltration (NF) membranes. A series of “carboxylated polyethersulfone” (CPES) copolymers with an increasing “molar ratio” (MR) of carboxyl units were used to prepare supports with diverse surface hydrophilicities by the classical nonsolvent-induced phase separation (NIPS) method. Then, the PA-TFC NF membranes were finely fabricated atop these supports by conventional interfacial polymerization (IP) reactions. The linkages between the surface hydrophilicity of the supports and the characteristics of the interfacially polymerized PA layers as well as the permselectivity of NF membranes were investigated systematically. The morphological details of the NF membranes indicate that the growth of PA layers can be adjusted through increasing the surface hydrophilicity of the supports. Moreover, the separation results reveal that the NF membrane fabricated on the relatively hydrophobic support exhibits lower permeability (7.04 L·m−2·h−1·bar−1) and higher selectivity (89.94%) than those of the ones prepared on the hydrophilic supports (14.64~18.99 L·m−2·h−1·bar−1 and 66.98~73.48%). A three-stage conceptual scenario is proposed to illustrate the formation mechanism of the PA layer in NF membranes, which is due to the variation of surface hydrophilicity of the supports. The overall findings specify how the surface hydrophilicity of the supports influences the formation of PA layers, which ultimately defines the separation performances of the corresponding NF membranes.