bluuebunny/crossref_metadata_2025 huggingface dataset:
Modelling and Comparative Analysis of Epoxy-Fly-Ash Composite with Alloys for Bracket Application
Authors: Raghunandan Abhijay B. , Chiniwar Dundesh S. , Hiremath Shivashankar , Sondar Pavankumar , Vishwanatha H. M.
Published: November 2022

The current study compares and analyses the fly-ash–epoxy composite structure with alloys for bracket applications. A dispersed reinforcement composite is created by combining epoxy and fly-ash. Three different prototypical brackets are modelled and analysed using the finite element method, and their results are compared to common alloys used in the manufacture of L-shaped brackets. The mechanical properties of the composite material are calculated using a rule of mixtures, and the properties of the composite material are modified by changing the percentage composition of fly-ash. Based on equivalent stress and total deformation, all geometrical models are analysed and compared. The analysis results appear to be appropriate for broadening the scope of the application of epoxy-based composites for small-scale and large-scale applications. The results also show that the composite material can be used to make a variety of structural elements with high design complexity, such as bulkheads and other structural components.
Shoreline Change Analysis Using Historical Multispectral Landsat Images of the Pacific Coast of Panama
Authors: Vallarino Castillo Ruby , Negro Valdecantos Vicente , Moreno Blasco Luis
Published: November 2022

The shoreline is the interface between sea and land influenced by natural, anthropogenic factors and climate change. The study of the evolution of the shoreline provides information to evaluate accretion or erosion processes. Shoreline erosion represents a threat to the safety of the coastal population, reducing the extension of the beach zone and making human settlements vulnerable to extreme events. This research presents the analysis of the evolution of the shoreline by multispectral images from Landsat satellites and the Digital Shoreline Analysis System (DSAS) of the Pacific Coast of Panama for the period of 1998–2021. The automated shoreline extraction was generated by combining remote sensing techniques, such as the Histogram Threshold Method and the Band Ratio Method, to generate binary images delineating the land and water zone. The most vulnerable zone, due to erosion processes and the exposition of urban areas, corresponds to the zone of Serena beach and Coronado beach with an average negative distance movement of −23.95 m. Finally, it was concluded that there is a general tendency of erosion processes in the study zone with a rate for long-term analysis of −1.12 m/y (zone I), −1.01 m/y (zone II), and −1.08 m/y (zone III).
Enhancing Sustainability of Corroded RC Structures: Estimating Steel-to-Concrete Bond Strength with ANN and SVM Algorithms
Authors: Singh Rohan , Arora Harish Chandra , Bahrami Alireza , Kumar Aman , Kapoor Nishant Raj , Kumar Krishna , Rai Hardeep Singh
Published: November 2022

The bond strength between concrete and corroded steel reinforcement bar is one of the main responsible factors that affect the ultimate load-carrying capacity of reinforced concrete (RC) structures. Therefore, the prediction of accurate bond strength has become an important parameter for the safety measurements of RC structures. However, the analytical models are not enough to estimate the bond strength, as they are built using various assumptions and limited datasets. The machine learning (ML) techniques named artificial neural network (ANN) and support vector machine (SVM) have been used to estimate the bond strength between concrete and corroded steel reinforcement bar. The considered input parameters in this research are the surface area of the specimen, concrete cover, type of reinforcement bars, yield strength of reinforcement bars, concrete compressive strength, diameter of reinforcement bars, bond length, water/cement ratio, and corrosion level of reinforcement bars. These parameters were used to build the ANN and SVM models. The reliability of the developed ANN and SVM models have been compared with twenty analytical models. Moreover, the analyzed results revealed that the precision and efficiency of the ANN and SVM models are higher compared with the analytical models. The radar plot and Taylor diagrams have also been utilized to show the graphical representation of the best-fitted model. The proposed ANN model has the best precision and reliability compared with the SVM model, with a correlation coefficient of 0.99, mean absolute error of 1.091 MPa, and root mean square error of 1.495 MPa. Researchers and designers can apply the developed ANN model to precisely estimate the steel-to-concrete bond strength.
Numerical Analysis of Factors Influencing the Ground Surface Settlement above a Cavity
Authors: Lee Kangil , Nam Junhee , Park Jeongjun , Hong Gigwon
Published: November 2022

In this study, ground stability was evaluated through vertical displacement distribution and surface settlement results. In particular, a finite element analysis was conducted considering various factors (namely, cavity type and area, traffic load, pavement thickness, and elastic modulus) that affect a road above a cavity. The aim of this study was to evaluate the effect of pavement layer and traffic load condition on surface settlement according to the cavity shape. Field measurement results were analyzed and compared with the results of previous studies to verify the reliability of the numerical analysis method applied herein. After performing the numerical analysis using the verified method, ground stability was evaluated by analyzing the underground mechanical behavior of a road above a cavity. To this end, the correlations among the vertical displacement distribution, surface settlement, and influencing factors obtained from the analysis results were analyzed. In the numerical analysis, the ground was simulated with a hardening soil model based on the elastoplastic theory. This mechanical soil model can accurately reproduce the behavior of actual ground and can closely represent the mechanical behavior of the soil surrounding a cavity according to the cavity generation. In addition, the elapsed time was not considered when applying a load on the pavement layer, and a uniformly distributed load was applied. Consequently, it was found that, with increasing cavity area and traffic load and decreasing pavement thickness and elastic modulus, the vertical displacement and maximum surface settlement above the cavity increased, and the reduction in ground stability was greater. Furthermore, the reduction in ground stability was greater when the cavity was rectangular than when it was circular.
Reinforcement Effect of Different Fibers on Asphalt Mastic
Authors: Xie Tingting , Zhao Kang , Wang Linbing
Published: November 2022

Fiber materials as an asphalt mixture additive and stabilizer can effectively improve the performance index of asphalt pavement. In this study, lignin and carbon fiber were used as modifiers to study their effects on the road performance of asphalt mastic. Based on the frequency sweep, linear amplitude sweep (LAS) and multi-stress creep recovery (MSCR) experiments were conducted to test the high-temperature rutting and medium-temperature fatigue resistance of asphalt mastic with different fiber incorporation and low-temperature performance tests based on bending beam rheometer (BBR). The results indicate that adding fibers increased the stiffness of the asphalt mastic, and the modification effect of lignin fibers was better than that of carbon fibers. Meanwhile, the characteristic flow index of the asphalt mastic gradually increased with the increase in temperature, indicating that it gradually became a near-Newtonian fluid at higher temperatures. The addition of fibers also improved the high temperature rutting resistance of the asphalt mastic but did not have an advantageous effect on fatigue and low temperature cracking resistance. Additionally, the fitting results of the four-parameter Burgers model show that the use of fiber modification decreases the proportion of elasticity and viscous creep compliance but increases the delayed elasticity part.
Transient Magnetic Properties of Non-Grain Oriented Silicon Steel under Multi-Physics Field
Authors: Wang Anqi , Tian Baozhi , Li Yulin , Xu Shibo , Zeng Lubin , Pei Ruilin
Published: November 2022

High-speed, high-efficiency and high-power density are the main development trends of high-performance motors in the future. At present, the design accuracy of traditional electric machines is already high enough; however, for the future demand of high performance and utilization in special environments (such as aviation and aerospace fields), more thorough research of materials’ performance under multi-physics field (MPF) conditions is still needed. In this paper, a test system that combined temperature, stress and electromagnetic fields along with other fields, at the same time, is built. It can accurately simulate the actual complex working conditions of the motor and explore the dynamic characteristics of non-grain oriented (NGO) silicon steel. The rationality of this method is verified by checking the test result of the prototype, and the calculation accuracy of the motor model is improved.
Displacement Calculation for Service Loads of Reinforced Concrete Beams and Slabs Using Physically Non-Linear Analysis
Authors: Bicelli Antonio Renato , Cantor Pedro , Wong Rafael , Arruda Mario Rui
Published: November 2022

This paper aims to use non-linear physical analysis to calculate the displacement of beams and slabs in a cracked state. This study uses the commercial software SAP2000 to perform a numerical analysis using the finite element formulation, applying the multi-layer method. Initially, a parametric study was carried out to evaluate the vertical displacement for service loads of reinforced concrete beams and slabs using different spans, support conditions and geometry. In order to validate the finite element model, the study compared displacement values for linear analysis using Bares tables. Subsequently, simplified methods of displacement calculation in the long term are applied, using an abacus from Comité Euro-International du Béton (CEB). These values are then compared with the physically non-linear analysis in the long-term cracked state with SAP2000. Two structural codes were used in the numerical and analytical methods, Regulamento de Estruturas de Betão Armado e Pré-Esforçado (REBAP) and Eurocode 2 (EC2), to evaluate their differences in deformation control. Therefore, the main goal is to establish comparisons between the two methods of analysis in order to show that non-linear finite element modelling provides values that are lower than the analytical calculation, thus allowing greater economy in the design of structural reinforced concrete elements. In addition, it can be noted that EC2 has some inconsistencies in the design of simply supported slabs, requiring a greater thickness than a flat square slab and that indirect deformation for REBAP is underestimated for beams and, in some cases, for slabs.
Coercivity and Exchange Bias in Ti-Doped Maghemite Nanoparticles
Authors: Narayanaswamy Venkatesha , Al-Omari Imaddin A. , Kamzin Aleksandr S. , Khurshid Hafsa , Khaleel Abbas , Issa Bashar , Obaidat Ihab M.
Published: November 2022

Ti-doped maghemite nanoparticles of average crystallite size 12.9 nm were synthesized using the sol–gel method. The XRD profile mainly showed the presence of maghemite phase with very small phases of TiO2 (rutile and anatase). Magnetization hysteresis loops of the nanoparticles were obtained between −4 T to +4 T at temperatures of 2, 10, 30, 50, 70, 100, 150, 200, and 300 K under field cooling (FC) of 1, 2, 3, and 4 T and zero-field cooling conditions (ZFC). The coercivity displayed nonmonotonic field dependence while it decreased sharply with temperature and vanished at 150 K at all fields. Horizontal hysteresis loop shifts were observed in the 2–150 K temperature range in both the ZFC and FC conditions. The exchange bias effect became negligible in both ZFC and FC states above 50 K. Magnetization vs. applied field measurements were conducted in both ZFC and FC cooled conditions at several temperatures in the range of 2–400 K, with spin freezing being observed below 50 K. The exchange bias effect obtained below 50 K is suggested to be attributed to the competing roles of the long-range dipolar and short-range exchange coupled interactions.
Modeling of Perforated Piezoelectric Plates
Authors: Mechkour Houari
Published: November 2022

In this article, we are interested in the behavior of a three-dimensional model of periodic perforated piezoelectric plate, when the thickness h of the plate and the size ε of the holes are small. We study the dependence of displacements and electric potential on h and ε, and give equivalent limits when h and ε tend towards zero. We compute analytical formulae for all effective properties of the periodic perforated piezoelectric plate.
Effect of the Duration of NSAID Use on COVID-19
Authors: Kim Kyeongmi , Yoon Siyeoung , Choi Junwon , Lee Soonchul
Published: November 2022

Background and Objectives: Non-steroidal anti-inflammatory drugs (NSAIDs) are commonly used to control pain and fever. However, their effect on COVID-19 infected patients has not been fully studied. In this study, we investigated the effect of the duration of NSAIDs use on COVID-19 infection and clinical outcomes. Materials and Methods: In South Korea, 25,739 eligible patients who received COVID-19 testing between 1 January and 31 July 2020, were included in this retrospective observational cohort analysis. Based on the date of the first COVID-19 test for each patient, NSAID prescription dates were used to separate patients into two groups (short-term group: <2 weeks; long-term group: 8–12 weeks). COVID-19 infectivity and clinical outcomes were analyzed. We used the propensity score-matching (PSM) method. Results: Of the 580 patients who had taken NSAIDs before the date of COVID-19 test, 534 and 46 patients were grouped in the short- and long-term NSAID-use groups, respectively. We did not find a statistically significant increased risk of COVID-19 infection (adjustment for age and sex, p = 0.413; adjustment for age, sex, region of residence, comorbidity, Charlson Comorbidity Index, and current use of medication, p = 0.259) or change in clinical outcomes, including conventional oxygen therapy, admission of intensive care unit, artificial ventilation, or death, between the two groups in which the PSM method was applied. Conclusions: The duration of NSAIDs use did not have a statistically significant effect on COVID-19 infectivity or clinical outcomes. However, further studies looking at clinical presentation and laboratory test results in a large number of people should be performed.
AFM Investigation of the Influence of Steam Flow through a Conical Coil Heat Exchanger on Enzyme Properties
Authors: Ivanov Yuri D. , Shumov Ivan D. , Tatur Vadim Y. , Valueva Anastasia A. , Kozlov Andrey F. , Ivanova Irina A. , Ershova Maria O. , Ivanova Nina D. , Stepanov Igor N. , Lukyanitsa Andrei A. , Ziborov Vadim S.
Published: November 2022

The present study is aimed at the revelation of subtle effects of steam flow through a conical coil heat exchanger on an enzyme, incubated near the heat exchanger, at the nanoscale. For this purpose, atomic force microscopy (AFM) has been employed. In our experiments, horseradish peroxidase (HRP) was used as a model enzyme. HRP is extensively employed as a model in food science in order to determine the influence of electromagnetic fields on enzymes. Adsorption properties of HRP on mica have been studied by AFM at the level of individual enzyme macromolecules, while the enzymatic activity of HRP has been studied by spectrophotometry. The solution of HRP was incubated either near the top or at the side of the conically wound aluminium pipe, through which steam flow passed. Our AFM data indicated an increase in the enzyme aggregation on mica after its incubation at either of the two points near the heat exchanger. At the same time, in the spectrophotometry experiments, a slight change in the shape of the curves, reflecting the HRP-catalyzed kinetics of ABTS oxidation by hydrogen peroxide, has also been observed after the incubation of the enzyme solution near the heat exchanger. These effects on the enzyme adsorption and kinetics can be explained by alterations in the enzyme hydration caused by the influence of the electromagnetic field, induced triboelectrically by the flow of steam through the heat exchanger. Our findings should thus be considered in the development of equipment involving conical heat exchangers, intended for either research or industrial use (including miniaturized bioreactors and biosensors). The increased aggregation of the HRP enzyme, observed after its incubation near the heat exchanger, should also be taken into account in analysis of possible adverse effects from steam-heated industrial equipment on the human body.
Enhanced Red Emission from Amorphous Silicon Carbide Films via Nitrogen Doping
Authors: Chen Guangxu , Chen Sibin , Lin Zewen , Huang Rui , Guo Yanqing
Published: November 2022

The enhanced red photoluminescence (PL) from Si-rich amorphous silicon carbide (a-SiCx) films was analyzed in this study using nitrogen doping. The increase in nitrogen doping concentration in films results in the significant enhancement of PL intensity by more than three times. The structure and bonding configuration of films were investigated using Raman and Fourier transform infrared absorption spectroscopies, respectively. The PL and analysis results of bonding configurations of films suggested that the enhancement of red PL is mainly caused by the reduction in nonradiative recombination centers as a result of the weak Si–Si bonds substituted by Si–N bonds.
Demonstration of Thin Film Bulk Acoustic Resonator Based on AlN/AlScN Composite Film with a Feasible Keff2
Authors: Nian Laixia , Zou Yang , Gao Chao , Zhou Yu , Fan Yuchen , Wang Jian , Liu Wenjuan , Liu Yan , Soon Jeffrey Bowoon , Cai Yao , Sun Chengliang
Published: November 2022

Film bulk acoustic resonators (FBARs) with a desired effective electromechanical coupling coefficient (Keff2) are essential for designing filter devices. Using AlN/AlScN composite film with the adjustable thickness ratio can be a feasible approach to obtain the required Keff2. In this work, we research the resonant characteristics of FBARs based on AlN/AlScN composite films with different thickness ratios by finite element method and fabricate FBAR devices in a micro-electromechanical systems process. Benefiting from the large piezoelectric constants, with a 1 μm-thick Al0.8Sc0.2N film, Keff2 can be twice compared with that of FBAR based on pure AlN films. For the composite films with different thickness ratios, Keff2 can be adjusted in a relatively wide range. In this case, a filter with the specific N77 sub-band is demonstrated using AlN/Al0.8Sc0.2N composite film, which verifies the enormous potential for AlN/AlScN composite film in design filters.
Anchoring Mechanism for Capsule Endoscope: Mechanical Design, Fabrication and Experimental Evaluation
Authors: Rehan Muhammad , Yeo Andrew G. , Yousuf Muhammad Uzair , Avci Ebubekir
Published: November 2022

Capsule endoscopes are widely used to diagnose gut-related problems, but they are passive in nature and cannot actively move inside the gut. This paper details the design process and development of an anchoring mechanism and actuation system to hold a capsule in place within the small intestine. The design centres around the mechanical structure of the anchor that makes use of compliant Sarrus linkage legs, which extend to make contact with the intestine, holding the capsule in place. Three variants with 2 legs, 3 legs and 4 legs of the anchoring mechanism were tested using a shape memory alloy spring actuator (5 mm × ϕ 3.4 mm). The experiments determine that all the variants can anchor at the target site and resist peristaltic forces of 346 mN. The proposed design is well suited for an intestine with a diameter of 19 mm. The proposed design allows the capsule endoscopes to anchor at the target site for a better and more thorough examination of the targeted region. The proposed anchoring mechanism has the potential to become a vital apparatus for clinicians to use with capsule endoscopes in the future.
Non-Dairy Fermented Beverages Produced with Functional Lactic Acid Bacteria
Authors: Zamfir Medana , Angelescu Iulia-Roxana , Voaides Catalina , Cornea Calina-Petruta , Boiu-Sicuia Oana , Grosu-Tudor Silvia-Simona
Published: November 2022

At present, there is an increasing interest in beverages of non-dairy origin, as alternatives to those based on milk, but having similar health-promoting properties. Fermentation with specific bacteria or consortia may enhance the functionality of these products. In our study, selected lactic acid bacteria, that have been previously shown to possess functional properties (antimicrobial activity, probiotic potential), were used for the fermentation of wheat bran combined with root vegetables. Strains were investigated for their safety, while the obtained beverages were characterized in terms of microbial content, physical, chemical, nutritional, and functional properties. None of the strains harbors virulence genes, but all of them possess genes for survival at low pH, starch metabolism, and vitamin biosynthesis. Three strains (Lactiplantibacillus plantarum BR9, L. plantarum P35, and Lactobacillus acidophilus IBB801) and two substrates (5% wheat bran with 10% red beetroot/carrots) were selected based on a preliminary assessment of the beverage’s sensory acceptability. These strains showed good growth and stability over time in the stored beverages. No enterobacteria were detected at the end of fermentations, while the final pH was, in most cases, below 3.5. Free phenolics, flavonoids, and DPPH scavenging effect increased during fermentation in all drinks, reaching 24h values that were much higher than in the unfermented substrates. Most of the obtained drinks were able to prevent the growth of certain pathogens, including Listeria monocytogenes ATCC 19111, Salmonella enterica ATCC 14028, Staphylococcus aureus ATCC 25923, and Escherichia coli ATCC 25922. The obtained beverages would combine the nutritiveness of the raw ingredients with the beneficial effect of fermentation (increasing shelf life, health-promoting effect, pleasant flavor, etc.). They would also fill a gap in the non-dairy probiotics sector, which is constantly increasing due to the increasing number of vegan people or people that cannot consume dairy products.
No Association between Low-Calorie Sweetener (LCS) Use and Overall Cancer Risk in the Nationally Representative Database in the US: Analyses of NHANES 1988–2018 Data and 2019 Public-Use Linked Mortality Files
Authors: Fulgoni Victor L. , Drewnowski Adam
Published: November 2022

Low-calorie sweeteners (LCS) serve to replace added sugars in beverages and foods. The present goal was to explore any potential links between LCS use and cancer risk using the nationally representative National Health and Nutrition Examination Surveys 1988–2018 linked to 2019 Public-Use Linked Mortality Files. Analyses were based on dietary intakes from 1988–1994 NHANES (n = 15,948) and 1999–2018 NHANES (n = 48,754) linked to mortality data. The 1988–1994 NHANES separated aspartame from saccharin consumption; later data did not. LCS consumers were more likely to be older, female, non-Hispanic White, and with higher education and incomes compared to nonconsumers. LCS consumers were less likely to smoke and had higher HEI-2015 scores indicating higher-quality diets. In the cross-sectional NHANES data, LCS use was associated with higher BMI and higher prevalence of obesity and diabetes. There was no indication that aspartame, saccharin, or all LCS had any impact on overall cancer mortality. By using nonconsumers as the reference group, the hazard ratio (95th confidence interval, CI) group trend for tertiles of LCS use for 1988–1994 for aspartame was 1.00 (0.89–1.12), for saccharin 0.96 (0.79–1.10), and for 1988–2018 for all LCS was 0.92 (0.88–1.101). The null group trend effects were seen for analyses stratified by age/gender. The present analyses confirm past US-based reports that LCS use was associated with higher socioeconomic status, lower prevalence of smoking, and generally higher-quality diets. No association with cancer mortality was observed.
The Efficacious Benefit of 25-Hydroxy Vitamin D to Prevent COVID-19: An In-Silico Study Targeting SARS-CoV-2 Spike Protein
Authors: Joseph Tomy Muringayil , Suresh Akshay Maniyeri , Kar Mahapatra Debarshi , Haponiuk Józef , Thomas Sabu
Published: November 2022

The environment has rapidly looked at proven specialist task forces in the aftermath of the COVID-19 pandemic to build public health policies and measures to mitigate the effects of emerging coronaviruses. According to the researchers, taking 10 μg of 25-hydroxy vitamin D daily is recommended to keep us safe. There have been several studies recently indicating that there is a reduced risk of contracting Coronavirus by 25-hydroxy vitamin D consumption, even though there is no scientific data to prove that one would not affect the COVID-19 viral infection by 25-hydroxy vitamin D consumption. In this regard, the present study investigates the important literature and the role of 25-hydroxy vitamin D to prevent COVID-19 infection by conducting an in-silico study with SARS-CoV-2 spike protein as a target. Lopinavir, a previously reported drug candidate, served as a reference standard for the study. MD simulations were carried out to improve predictions of receptor-ligand complexes which offer novelty and strength to the current study. MD simulation protocols were explored and subjected to 25-hydroxy vitamin D and a known drug, Lopinavir. Comparison of ligands at refined models to the crystal structure led to promising results. Appropriate timescale simulations have been used to understand the activation mechanism, the role of water networks for receptor function, and the ligand binding process. Furthermore, MD simulations in combination with free energy calculations have also been carried out for lead optimization, evaluation of ligand binding modes, and assessment of ligand selectivity. From the results, 25-hydroxy vitamin D was discovered to have the vital interaction and highest potency in LBE, lower RMSD, and lower inhibition intensity similar to the standard. The findings from the current study suggested that 25-hydroxy vitamin D would be more effective in treating COVID-19. Compared with Lopinavir, 25-hydroxy vitamin D had the most potent interaction with the putative binding sites of the SARS-CoV-2 spike protein of COVID-19.
Antibody-Based In Vivo Imaging of Central Nervous System Targets—Evaluation of a Pretargeting Approach Utilizing a TCO-Conjugated Brain Shuttle Antibody and Radiolabeled Tetrazines
Authors: Bredack Christoph , Edelmann Martin R. , Borroni Edilio , Gobbi Luca C. , Honer Michael
Published: November 2022

Bioorthogonal pretargeted imaging using the inverse-electron-demand Diels–Alder (IEDDA) reaction between a tetrazine (Tz) and a trans-cyclooctene (TCO) represents an attractive strategy for molecular imaging via antibodies. The advantages of using a pretargeted imaging approach are on the one hand the possibility to achieve a high signal-to-noise ratio and imaging contrast; on the other hand, the method allows the uncoupling of the biological half-life of antibodies from the physical half-life of short-lived radionuclides. A brain-penetrating antibody (mAb) specific for β-amyloid (Aβ) plaques was functionalized with TCO moieties for pretargeted labeling of Aβ plaques in vitro, ex vivo, and in vivo by a tritium-labeled Tz. The overall aim was to explore the applicability of mAbs for brain imaging, using a preclinical model system. In vitro clicked mAb–TCO–Tz was able to pass the blood–brain barrier of transgenic PS2APP mice and specifically visualize Aβ plaques ex vivo. Further experiments showed that click reactivity of the mAb–TCO construct in vivo persisted up to 3 days after injection by labeling Aβ plaques ex vivo after incubation of brain sections with the Tz in vitro. An attempted in vivo click reaction between injected mAb–TCO and Tz did not lead to significant labeling of Aβ plaques, most probably due to unfavorable in vivo properties of the used Tz and a long half-life of the mAb–TCO in the blood stream. This study clearly demonstrates that pretargeted imaging of CNS targets via antibody-based click chemistry is a viable approach. Further experiments are warranted to optimize the balance between stability and reactivity of all reactants, particularly the Tz.
Aptamers as Smart Ligands for Targeted Drug Delivery in Cancer Therapy
Authors: Wei Zongyi , Zhou Yuxin , Wang Rongjie , Wang Jin , Chen Zhenhua
Published: November 2022

Undesirable side effects and multidrug tolerance are the main holdbacks to the treatment of cancer in conventional chemotherapy. Fortunately, targeted drug delivery can improve the enrichment of drugs at the target site and reduce toxicity to normal tissues and cells. A targeted drug delivery system is usually composed of a nanocarrier and a targeting component. The targeting component is called a “ligand”. Aptamers have high target affinity and specificity, which are identified as attractive and promising ligands. Therefore, aptamers have potential application in the development of smart targeting systems. For instance, aptamers are able to efficiently recognize tumor markers such as nucleolin, mucin, and epidermal growth factor receptor (EGFR). Besides, aptamers can also identify glycoproteins on the surface of tumor cells. Thus, the aptamer-mediated targeted drug delivery system has received extensive attention in the application of cancer therapy. This article reviews the application of aptamers as smart ligands for targeted drug delivery in cancer therapy. Special interest is focused on aptamers as smart ligands, aptamer-conjugated nanocarriers, aptamer targeting strategy for tumor microenvironment (TME), and aptamers that are specified to crucial cancer biomarkers for targeted drug delivery.
Genetically Engineered Extracellular Vesicles Harboring Transmembrane Scaffolds Exhibit Differences in Their Size, Expression Levels of Specific Surface Markers and Cell-Uptake
Authors: Zhang Jiayi , Brown Annie , Johnson Brendan , Diebold David , Asano Kyle , Marriott Gerard , Lu Biao
Published: November 2022

Background: Human cell-secreted extracellular vesicles (EVs) are versatile nanomaterials suitable for disease-targeted drug delivery and therapy. Native EVs, however, usually do not interact specifically with target cells or harbor therapeutic drugs, which limits their potential for clinical applications. These functions can be introduced to EVs by genetic manipulation of membrane protein scaffolds, although the efficiency of these manipulations and the impacts they have on the properties of EVs are for the most part unknown. In this study, we quantify the effects of genetic manipulations of different membrane scaffolds on the physicochemical properties, molecular profiles, and cell uptake of the EVs. Methods: Using a combination of gene fusion, molecular imaging, and immuno-based on-chip analysis, we examined the effects of various protein scaffolds, including endogenous tetraspanins (CD9, CD63, and CD81) and exogenous vesicular stomatitis virus glycoprotein (VSVG), on the efficiency of integration in EV membranes, the physicochemical properties of EVs, and EV uptake by recipient cells. Results: Fluorescence imaging and live cell monitoring showed each scaffold type was integrated into EVs either in membranes of the endocytic compartment, the plasma membrane, or both. Analysis of vesicle size revealed that the incorporation of each scaffold increased the average diameter of vesicles compared to unmodified EVs. Molecular profiling of surface markers in engineered EVs using on-chip assays showed the CD63-GFP scaffold decreased expression of CD81 on the membrane surface compared to control EVs, whereas its expression was mostly unchanged in EVs bearing CD9-, CD81-, or VSVG-GFP. The results from cell uptake studies demonstrated that VSVG-engineered EVs were taken up by recipient cells to a greater degree than control EVs. Conclusion: We found that the incorporation of different molecular scaffolds in EVs altered their physicochemical properties, surface protein profiles, and cell-uptake functions. Scaffold-induced changes in the physical and functional properties of engineered EVs should therefore be considered in engineering EVs for the targeted delivery and uptake of therapeutics to diseased cells.
Bioorthogonal Chemistry Approach for the Theranostics of GRPR-Expressing Cancers
Authors: D’Onofrio Alice , Silva Francisco , Gano Lurdes , Raposinho Paula , Fernandes Célia , Sikora Arkadiusz , Wyczółkowska Monika , Mikołajczak Renata , Garnuszek Piotr , Paulo António
Published: November 2022

Several gastrin-releasing peptide receptor (GRPR) antagonists with improved in vivo behavior have been recently developed and tested in the clinic. However, despite the generally mild side effects of peptide receptor radionuclide therapy (PRRT), toxicity has been observed due to high doses delivered to nontarget tissues, especially in the kidneys and pancreas. Previous experiences with radiolabeled peptides opened a unique opportunity to explore GRPR pretargeting using clickable bombesin antagonists. Toward this goal, we used clickable DOTA-like radiocomplexes which have been previously evaluated by our group. We functionalized a potent GRPR antagonist with a clickable TCO moiety using two different linkers. These precursors were then studied to select the compound with the highest GRPR binding affinity and the best pharmacokinetics to finally explore the advantages of the devised pretargeting approach. Our results provided an important proof of concept toward the development of bioorthogonal approaches to GRPR-expressing cancers, which are worth investigating further to improve the in vivo results. Moreover, the use of clickable GRPR antagonists and DOTA/DOTAGA derivatives allows for fine-tuning of their pharmacokinetics and metabolic stability, leading to a versatile synthesis of new libraries of (radio)conjugates useful for the development of theranostic tools toward GRPR-expressing tumors.
Non-Radiative Transitions of Holes on Mercury Vacancies in Narrow-Gap HgCdTe
Authors: Kozlov Dmitry V. , Rumyantsev Vladimir V. , Ikonnikov Anton V. , Utochkin Vladimir V. , Razova Anna A. , Mazhukina Ksenia A. , Mikhailov Nikolay N. , Dvoretsky Sergey A. , Morozov Sergey V. , Gavrilenko Vladimir I.
Published: November 2022

Mercury vacancies, acting as double acceptors, are the dominant point defects in ternary HgCdTe alloys. Though HgCdTe is one of the leading materials in infrared optoelectronics, the energy spectra of the vacancies are still a matter of some debate. This work investigated the rates at which holes are captured to a singly ionized mercury vacancy via acoustic phonon emission in narrow-gap Hg1−xCdxTe with technologically relevant x~0.22. Combined with the calculated rates of intracenter transitions, the data allow one to predict the most pronounced optical transitions in the emission spectrum of a double-charged acceptor. The results are sustained by the photoluminescence spectroscopy in the terahertz domain, allowing one to identify the emission band that is related to neutral vacancies.
Electrospinning Technique for Fabrication of Coaxial Nanofibers of Semiconductive Polymers
Authors: Serrano-Garcia William , Ramakrishna Seeram , Thomas Sylvia W.
Published: November 2022

In this work, the electrospinning technique is used to fabricate a polymer-polymer coaxial structure nanofiber from the p-type regioregular polymer poly(3-hexylthiophene-2,5-diyl) (P3HT) and the n-type conjugated ladder polymer poly(benzimidazobenzophenanthroline) (BBL) of orthogonal solvents. Generally, the fabrication of polymeric coaxial nanostructures tends to be troublesome. Using the electrospinning technique, P3HT was successfully used as the core, and the BBL as the shell, thus conceptually forming a p-n junction that is cylindrical in form with diameters in a range from 280 nm to 2.8 µm. The UV–VIS of P3HT/PS blend solution showed no evidence of separation or precipitation, while the combined solutions of P3HT/PS and BBL were heterogeneous. TEM images show a well-formed coaxial structure that is normally not expected due to rapid reaction and solidification when mixed in vials in response to orthogonal solubility. For this reason, extruding it by using electrostatic forces promoted a quick elongation of the polymers while forming a concise interface. Single nanofiber electrical characterization demonstrated the conductivity of the coaxial surface of ~1.4 × 10−4 S/m. Furthermore, electrospinning has proven to be a viable method for the fabrication of pure semiconducting coaxial nanofibers that can lead to the desired fabrication of fiber-based electronic devices.
Polydimethylsiloxanes with Grafted Dibenzoylmethanatoboron Difluoride: Synthesis and Properties
Authors: Belova Anastasia S. , Khchoyan Arevik G. , Il’ina Tatiana M. , Kononevich Yuriy N. , Ionov Dmitry S. , Sazhnikov Viacheslav A. , Khanin Dmitry A. , Nikiforova Galina G. , Vasil’ev Viktor G. , Muzafarov Aziz M.
Published: November 2022

A method for the preparation of polydimethylsiloxanes with grafted methoxy-substituted dibenzoylmethanatoboron difluoride has been described. The structures of prepared polymers were confirmed using NMR, IR spectroscopy and gel permeation chromatography methods. Their thermal properties were investigated using thermal gravimetric analysis, differential scanning calorimetry and thermomechanical analysis. The prepared polymers had good thermal (Td5% up to 393 °C) and thermo-oxidative (Td5% = 413 °C) stability. The polymers started to transit in a viscous flow state at about 40 °C (for 3 a) and at about 20 °C (for 3 b). The viscoelastic characteristics of prepared polymers were determined in the sinusoidal oscillating vibrations mode. It was shown that the studied polymers at low frequencies at room temperature are viscoelastic fluids (G′ < G″). Increasing the frequency led to inversion (crossover) of dependences G′ and G″, which indicated the transition of polymers from viscous to elastomeric behavior characteristics, and the beginning of the formation of a physical network. Optical properties were studied using electron absorption, steady-state and time-resolved fluorescence spectroscopy. It was shown that intramolecular H-dimers exist in the ground state. The polymers studied had a bright fluorescence in the solution and in the solid state, consisting of bands of monomer and excimer emission. Thermally-activated delayed fluorescence was observed in the solution and the solid state. The prepared polymers possess intriguing properties that make them useful as optical materials, sensors or imaging agents.
Desire for Purity and Inevitable Contamination: Derrida and Prayer
Authors: Pietrogrande Filippo
Published: November 2022

The aim of this paper is to understand the reasons underlying Derrida’s interest in the phenomenon of prayer. The article traces the different directions taken by the topic in the over forty-year long reflection of the philosopher. I start off by highlighting the dichotomic structure around which Derrida lays out his entire analysis of prayer, describing it, in general terms, as an opposition between determination and indetermination: on the one side, the multiple concrete manifestations of prayer; on the other, the possibility of a pure address to the other as other, not marked by metaphysics. I proceed by examining the qualities of what Derrida calls the “pure prayer”, or “prayer in itself”, in direct contrast with the praising prayer. The issue concerning the autonomy and the specificity of this indeterminate act of addressing is especially taken into consideration. The fundamental question remains whether a pure prayer is truly conceivable, or whether its contamination is as inevitable as necessary for the actual possibility of religion, theology, and prayer itself.
Identity in Transnational Buddhism—The Case of a Chinese Buddhist Nun in Shan State, Myanmar
Authors: Cheng Wei-Yi
Published: November 2022

This paper will use the case study of a Chinese Mahayana Buddhist nun in a border town in Shan state, Myanmar, to explore the importance of identity in transnational Buddhism. Three life stories related to the Chinese Mahayana Buddhist nun will be told; that is, stories of her mother, her tonsure grandmaster, and herself. The main discussion of this paper is on the analysis of three dimensions of the nun’s identity, which are overseas Chinese, Mahayana monastic, and Buddhist nun. This paper will argue that identity is a crucial factor in transnational Buddhism, for identity helps an individual to communicate, interact, and take actions with others transnationally.
Clutter Jamming Suppression for Airborne Distributed Coherent Aperture Radar Based on Prior Clutter Subspace Projection
Authors: Miao Yingjie , Liu Feifeng , Liu Hongjie , Li Hao
Published: November 2022

Airborne distributed coherent aperture radar is of great significance for expanding the detection capability of the system. However, the extra observation dimension introduced by its sparse configuration also deteriorates the performance of traditional adaptive processing in a non-uniform environment. This paper focuses on moving target detection when the system works in a clutter–jamming-coexisting environment. In order to make full use of the specific low-rank structure to reduce the requirement for training data, this paper proposes a two-stage adaptive scheme that cancels jamming and clutter separately. The proposed suppression scheme first excludes the mainlobe jamming component from the training data based on the prior clutter subspace projection and performs intra-node clutter suppression. Then, the remaining jamming is jointly canceled based on the covariance obtained with its inter-pulse mixture model. Numerical examples show that this scheme can effectively reduce the blocking effect of main lobe jamming on high-speed targets but, due to the inaccuracy of the prior subspace, there is a certain additional loss of signal-to-noise ratio for near stationary targets. The simulation also shows that the proposed scheme is equally applicable to systems with a time-varying distributed geometry.
Experimental Tests for Fluorescence LIDAR Remote Sensing of Submerged Plastic Marine Litter
Authors: Palombi Lorenzo , Raimondi Valentina
Published: November 2022

Marine plastic litter has become a global challenge, affecting all regions of the planet, with massive plastic input to the marine environment every year. Novel remote sensing methods can greatly contribute to face this complex issue with their ability to provide large-scale data. Here we present experimental tests exploring the potential of the hyperspectral fluorescence LIDAR technique for the detection and characterization of plastics when plunged into a layer of natural water. The experiments were carried out in the laboratory by using an in-house developed fluorescence hyperspectral LIDAR with 355 nm excitation from a distance of 11 m on weathered commercial plastic samples plunged into natural water. Results showed the capability of the technique to detect the fluorescence features of several types of plastics, also when plunged into water, and to decouple it from the fluorescence due to colored dissolved organic matter and from Raman scattering due to water molecules. Discrimination of plastics against other marine debris, e.g., vegetation and wood, has also been discussed. The study lays a basis for fluorescence LIDAR remote sensing of plastics in marine environment and paves the way to the detection of MPL also in conditions (e.g., submerged or transparent plastics) that are likely to be challenging by using other passive remote sensing techniques.
A Method for the Automatic Extraction of Support Devices in an Overhead Catenary System Based on MLS Point Clouds
Authors: Zhang Shengyuan , Meng Qingxiang , Hu Yulong , Fu Zhongliang , Chen Lijin
Published: November 2022

A mobile laser scanning (MLS) system can acquire railway scene information quickly and provide a data foundation for regular railway inspections. The location of the catenary support device in an electrified railway system has a direct impact on the regular operation of the power supply system. However, multi-type support device data accounts for a tiny proportion of the whole railway scene, resulting in its poor characteristic expression in the scene. Therefore, using traditional point cloud filtering or point cloud segmentation methods alone makes it difficult to achieve an effective segmentation and extraction of the support device. As a result, this paper proposes an automatic extraction algorithm for complex railway support devices based on MLS point clouds. First, the algorithm obtains hierarchies of the pillar point clouds and the support device point clouds in the railway scene through high stratification and then realizes the noise that was point-cloud-filtered in the scene. Then, the center point of the pillar device is retrieved from the pillar corridor by a neighborhood search, and then the locating and initial extracting of the support device are realized based on the relatively stable spatial topological relationship between the pillar and the support device. Finally, a post-processing optimization method integrating the pillar filter and the voxelized projection filter is designed to achieve the accurate and efficient extraction of the support device based on the feature differences between the support device and other devices in the initial extraction results. Furthermore, in the experimental part, we evaluate the treatment effect of the algorithm in six types of support devices, three types of support device distribution scenes, and two types of railway units. The experimental results show that the average extraction IoU of the multi-type support device, support device distribution scenes, and railway unit were 97.20%, 94.29%, and 96.11%, respectively. In general, the proposed algorithm can achieve the accurate and efficient extraction of various support devices in different scenes, and the influence of the algorithm parameters on the extraction accuracy and efficiency is elaborated in the discussion section.