bluuebunny/crossref_metadata_2025 huggingface dataset:
Laser Drilling in Alumina Ceramics Using a Combination of Laser Pulses in the Free-Running and Q-Switched Modes
Authors: Gavrilov Gennady , Kurkin Andrey , Rusin Evgeny , Bazhenov Evgeny
Published: April 2023

The possibility of using a two-pulse laser action consisting of a pulse of the free-running pulse followed by the Q-switched pulse in the processes of laser drilling in alumina ceramics is considered. A diagram of a laser machine for implementing the proposed processing method and the method for determining the energy required to form the through hole and the drilling time are presented. For thermal exposure, pulsed radiation of Nd:YAG of the laser operating in the free-running mode (pulse duration 0.5 ms, energy up to 0.3 J) was used. The Q-switched pulse was generated using a second Nd:YAG laser (pulse duration 25–30 ns, energy up to 0.03 J). The laser radiation was focused on the surface of the material at one point. The time between the start of generation of the first and second lasers varied in the range of 0–1000 μs. The optimal delay time for the start of the generation of the second laser relative to the first was determined experimentally. The obtained results showed that the combination of the free-running pulse and the Q-switched pulse can significantly increase the efficiency of laser machining of ceramics and improve the hole quality. This scheme turned out to be promising for optimizing parameters of the process of laser drilling in thin-sheet alumina ceramics. The obtained results obtained have great potential in the field of precision laser machining of ceramics.
Marine Bioactive Peptides—Structure, Function and Application
Authors: Chi Chang-Feng , Wang Bin
Published: April 2023

Marine organisms live in harsh marine habitats, causing them to have significantly different and more diverse proteins than those of terrestrial organisms [...]
Impact of Sarcopenia on Percutaneous Epidural Balloon Neuroplasty in Patients with Lumbar Spinal Stenosis: A Retrospective Analysis
Authors: Han Yun-A , Kwon Hyun-Jung , Lee Kunhee , Son Min-Gi , Kim Hotaek , Choi Seong-Soo , Shin Jin-Woo , Kim Doo-Hwan
Published: April 2023

Background and Objectives: With the aging population, the incidence of degenerative lumbar spinal stenosis (LSS) is increasing. Sarcopenia is an age-related muscular decrease. Although epidural balloon neuroplasty is effective in patients with LSS refractory to conventional treatments, its effect has not been assessed in patients with sarcopenia. Therefore, this study evaluated the effect of epidural balloon neuroplasty in patients with LSS and sarcopenia. Materials and Methods: This retrospective study reviewed the following details from the electronic medical records: patient characteristics, including sex, age, body mass index, diabetes, hypertension, stenosis grading, pain duration, location, pain intensity, and medications. Back and leg pain intensity was evaluated before and after the procedure at one, three, and six months during the follow-up period. A generalized estimating equations model was used at six months follow-up. Patients were divided into sarcopenia and non-sarcopenia groups using the cross-sectional area of the psoas muscle at the level of L3 on magnetic resonance imaging. Results: A total of 477 patients were included (sarcopenia group: 314 patients, 65.8%; non-sarcopenia group: 163 patients, 34.2%). Age, sex, body mass index, and medication quantification scale III were statistically different between both groups. The generalized estimating equations analyses—with unadjusted and adjusted estimation—revealed a significantly reduced pain intensity after the procedure compared to the baseline in both groups. The difference in pain intensity between both groups was not statistically different. Conclusions: Percutaneous epidural balloon neuroplasty may be considered for patients with chronic lumbar LSS regardless of accompanying sarcopenia.
A Comprehensive Review of the Effects of Extracorporeal Shock Wave Therapy on Stroke Patients: Balance, Pain, Spasticity
Authors: Lee Jung-Ho , Kim Eun-Ja
Published: April 2023

Stroke remains a leading cause of disability worldwide, with survivors often experiencing impairments in balance, pain, spasticity, and control that limit their ability to perform daily living activities. Extracorporeal shock wave therapy (ESWT) has emerged as a potential treatment modality to improve these outcomes in stroke patients. This review aims to provide a comprehensive examination of the effects of ESWT on stroke patients, focusing on the theoretical background, balance, pain reduction, muscle spasticity and control, and upper and lower extremities. This study reviewed the use of ESWT in treating balance, pain, and spasticity in stroke patients, focusing on articles published in PubMed between January 2003 and January 2023. Systematic reviews related to stroke were used to provide an overview of stroke, and a total of 33 articles related to balance, pain, and spasticity were selected. ESWT has several shock wave generation methods and application methods, and it has been shown to have positive therapeutic effects on various aspects of rehabilitation for stroke patients, such as improving balance, reducing pain, decreasing muscle spasticity and increasing control, and enhancing functional activities of the upper and lower extremities. The efficacy of ESWT may vary depending on the patient’s condition, application method, and treatment area. Therefore, it is important to apply ESWT according to the individual characteristics of each patient in clinical practice to maximize its potential benefits.
Enhancing Cancer Diagnosis with Real-Time Feedback: Tumor Metabolism through Hyperpolarized 1-13C Pyruvate MRSI
Authors: Sharma Gaurav , Enriquez José S. , Armijo Ryan , Wang Muxin , Bhattacharya Pratip , Pudakalakatti Shivanand
Published: April 2023

This review article discusses the potential of hyperpolarized (HP) 13C magnetic resonance spectroscopic imaging (MRSI) as a noninvasive technique for identifying altered metabolism in various cancer types. Hyperpolarization significantly improves the signal-to-noise ratio for the identification of 13C-labeled metabolites, enabling dynamic and real-time imaging of the conversion of [1-13C] pyruvate to [1-13C] lactate and/or [1-13C] alanine. The technique has shown promise in identifying upregulated glycolysis in most cancers, as compared to normal cells, and detecting successful treatment responses at an earlier stage than multiparametric MRI in breast and prostate cancer patients. The review provides a concise overview of the applications of HP [1-13C] pyruvate MRSI in various cancer systems, highlighting its potential for use in preclinical and clinical investigations, precision medicine, and long-term studies of therapeutic response. The article also discusses emerging frontiers in the field, such as combining multiple metabolic imaging techniques with HP MRSI for a more comprehensive view of cancer metabolism, and leveraging artificial intelligence to develop real-time, actionable biomarkers for early detection, assessing aggressiveness, and interrogating the early efficacy of therapies.
Numerical Analysis of Droplet Impacting on an Immiscible Liquid via Three-Phase Field Method
Authors: Hu Qingming , Hu Fengshi , Xu Donghui , Zhang Kailiang
Published: April 2023

In this work, we establish a two-dimensional axisymmetric simulation model to numerically study the impacting behaviors between oil droplets and an immiscible aqueous solution based on the three-phase field method. The numerical model is established by using the commercial software of COMSOL Multiphysics first and then validated by comparing the numerical results with the previous experimental study. The simulation results show that under the impact of oil droplets, a crater will form on the surface of the aqueous solution, which firstly expands and then collapses with the transfer and dissipation of kinetic energy of this three-phase system. As for the droplet, it flattens, spreads, stretches, or immerses on the crater surface and finally achieves an equilibrium state at the gas–liquid interface after experiencing several sinking-bouncing circles. The impacting velocity, fluid density, viscosity, interfacial tension, droplet size, and the property of non-Newtonian fluids all play important roles in the impact between oil droplets and aqueous solution. The conclusions can help to cognize the mechanism of droplet impact on an immiscible fluid and provide useful guidelines for those applications concerning droplet impact.
Triple-Band Surface Plasmon Resonance Metamaterial Absorber Based on Open-Ended Prohibited Sign Type Monolayer Graphene
Authors: Lai Runing , Shi Pengcheng , Yi Zao , Li Hailiang , Yi Yougen
Published: April 2023

This paper introduces a novel metamaterial absorber based on surface plasmon resonance (SPR). The absorber is capable of triple-mode perfect absorption, polarization independence, incident angle insensitivity, tunability, high sensitivity, and a high figure of merit (FOM). The structure of the absorber consists of a sandwiched stack: a top layer of single-layer graphene array with an open-ended prohibited sign type (OPST) pattern, a middle layer of thicker SiO2, and a bottom layer of the gold metal mirror (Au). The simulation of COMSOL software suggests it achieves perfect absorption at frequencies of fI = 4.04 THz, fII = 6.76 THz, and fIII = 9.40 THz, with absorption peaks of 99.404%, 99.353%, and 99.146%, respectively. These three resonant frequencies and corresponding absorption rates can be regulated by controlling the patterned graphene’s geometric parameters or just adjusting the Fermi level (EF). Additionally, when the incident angle changes between 0~50°, the absorption peaks still reach 99% regardless of the kind of polarization. Finally, to test its refractive index sensing performance, this paper calculates the results of the structure under different environments which demonstrate maximum sensitivities in three modes: SI = 0.875 THz/RIU, SII = 1.250 THz/RIU, and SIII = 2.000 THz/RIU. The FOM can reach FOMI = 3.74 RIU−1, FOMII = 6.08 RIU−1, and FOMIII = 9.58 RIU−1. In conclusion, we provide a new approach for designing a tunable multi-band SPR metamaterial absorber with potential applications in photodetectors, active optoelectronic devices, and chemical sensors.
Hardware Error Correction for MZI-Based Matrix Computation
Authors: Hou Huihuang , Xu Pengfei , Zhou Zhiping , Su Hui
Published: April 2023

With the rapid development of artificial intelligence, the electronic system has fallen short of providing the needed computation speed. It is believed that silicon-based optoelectronic computation may be a solution, where Mach–Zehnder interferometer (MZI)-based matrix computation is the key due to its advantages of simple implementation and easy integration on a silicon wafer, but one of the concerns is the precision of the MZI method in the actual computation. This paper will identify the main hardware error sources of MZI-based matrix computation, summarize the available hardware error correction methods from the perspective of the entire MZI meshes and a single MZI device, and propose a new architecture that will largely improve the precision of MZI-based matrix computation without increasing the size of the MZI’s mesh, which may lead to a fast and accurate optoelectronic computing system.
A Wafer Pre-Alignment Algorithm Based on Weighted Fourier Series Fitting of Circles and Least Squares Fitting of Circles
Authors: Chen Jingsong , Lan Zhou , Xue Cheng , Lan Jun , Liu Zhenghao , Yang Yong
Published: April 2023

The wafer pre-aligner is a crucial component in the lithography process to correct the wafer center and notch orientation. To improve the precision and the efficiency of pre-alignment, a new method to calibrate the center and the orientation of a wafer based on the weighted Fourier series fitting of circles (WFC) method and the least squares fitting of circles (LSC) method, respectively, is proposed. The WFC method effectively suppressed the influence of the outliers and had high stability compared with the LSC method when fitted to the center of the circle. While the weight matrix degenerated to the identity matrix, the WFC method degenerated into the Fourier series fitting of circles (FC) method. The fitting efficiency of the FC method is 28% higher than that of the LSC method, and the fitting accuracy of the center of the FC method is the same as that of the LSC method. In addition, the WFC method and the FC method perform better than the LSC method in radius fitting. The pre-alignment simulation results showed that the absolute position accuracy of the wafer was ±2 µm, the absolute direction accuracy was 0.01°, and the total calculation time was less than 3.3 s in our platform.
Research on the Method of Reducing Dynamic Cutting Force in Aspheric Machining
Authors: Zhuang Guilin , Liu Hanzhong , Zong Wenjun
Published: April 2023

With the rapid development of photoelectric communication and other fields, the demand for high-precision aspheric mirrors has been increasing. Predicting dynamic cutting forces is vital in selecting machining parameters and also affects the surface quality of the machined surface. This study comprehensively considers the effects of different cutting parameters and workpiece shape parameters on dynamic cutting force. The actual width of cut, depth of cut, and shear angle are modelled while considering the effects of vibration. A dynamic cutting-force model considering the aforementioned factors is then established. Using experimental results, the model accurately predicts the average value of dynamic cutting force under different parameters and the range of fluctuation of dynamic cutting force, with a controlled relative error of about 15%. The influence of workpiece shape and workpiece radial size on dynamic cutting force is also considered. The experimental results show that the greater the surface slope, the more dramatic the dynamic cutting force fluctuations. This lays the foundation for subsequent writing on vibration suppression interpolation algorithms. The influence of the radius of the tool tip on dynamic cutting forces leads to the conclusion that to achieve the goal of reducing the fluctuation of cutting forces, diamond tools with different parameters should be selected for different feed rates. Finally, a new interpolation-point planning algorithm is used to optimize the position of interpolation points in the machining process. This proves the reliability and practicability of the optimization algorithm. The results of this study are of great significance to the processing of high-reflectivity spherical/aspheric surfaces.
Experimental and Theoretical Studies of Different Parameters on the Thermal Conductivity of Nanofluids
Authors: Qin Jun , Tao Yuequn , Liu Qiusheng , Li Zilong , Zhu Zhiqiang , He Naifeng
Published: April 2023

This work experimentally investigated the effects of different factors, including nanoparticle size and type, volume fraction, and base fluid, on the thermal conductivity enhancement of nanofluids. The experimental results indicate that the thermal conductivity enhancement of nanofluids is proportional to the thermal conductivity of the nanoparticles, with the enhancement being more pronounced for fluids with lower thermal conductivity. Meanwhile, the thermal conductivity of nanofluids decreases with increasing particle size and increases with increasing volume fraction. In addition, elongated particles are superior to spherical ones for thermal conductivity enhancement. This paper also proposes a thermal conductivity model by introducing the effect of nanoparticle size based on the previous classical thermal conductivity model via the method of dimensional analysis. This model analyzes the magnitude of influencing factors on the thermal conductivity of nanofluid and proposes suggestions for an improvement in thermal conductivity enhancement.
Closure of the Eastern Paleo-Asian Ocean: Evidence from Permian–Triassic Volcanic Rocks in the Northern Margin of the North China Craton
Authors: Xue Jixiang , Shi Yi , Liu Zhenghong , Xue Linfu
Published: April 2023

The Central Asian Orogenic Belt (CAOB) is the world’s largest accretionary orogenic belt, and its formation is related to the closure of the Paleo-Asian Ocean (PAO). However, the closure time and style of the PAO remain controversial. To address these issues, this paper presents zircon U-Pb dating, whole-rock geochemistry and zircon Lu-Hf isotope analyses of the volcanic rocks in the Faku-Kaiyuan area on the northern margin of the North China Craton. The results show that the Bachagou andesites formed in the Early Permian (287 ± 2 Ma), while the Chaijialing andesites and dacites formed in the Late Permian (253.3 ± 3.7 Ma) and Middle Triassic (244.3 ± 1.3 Ma), respectively. The Bachagou andesites and Chaijialing andesites are enriched in LILEs and LREEs and depleted in HFSEs and HREEs, indicating that they formed in the active continental margins. The Chaijialing dacites show similar geochemical signatures to adakite and formed in a syn-collisional setting. Geochemistry and isotopic analysis indicates that the Bachagou andesites were derived from a partial melting of the mantle wedge that was metasomatized by subduction fluids. The Chaijialing andesites were generated from a metasomatized mantle by slab-derived and sediment fluids. The Chaijialing dacites formed by a partial melting of thickened lower crust. Combined with previous research results, we can conclude that the Eastern PAO closed by a scissor-like movement from west to east during the Late Permian–Middle Triassic.
Electrically Conductive Silicate Composite for Protection against Electrocorrosion
Authors: Plugin Andrii , Rucińska Teresa , Borziak Olga , Pluhin Oleksii , Zhuravel Vitalii
Published: April 2023

This article presents the results of a study on the development of an anti-corrosion plaster composite based on water glass with increased electrical conductivity. Known acid-resistant quartz-fluorosilicate composites containing liquid sodium silicate, sodium fluorosilicate and acid-resistant high-silica filler in the form of quartz, andesite or diabase powder were chosen as the prototype. The low water resistance and low adhesion to Portland cement concrete of these composites limits their application. By adding granulated blast-furnace slag to the composite, it was possible to increase the water resistance of the solution and its adhesion to concrete. The addition of graphite filler to the composite made it possible to increase the electrical conductivity. This made it possible to obtain not only a corrosion-resistant (to chemical and physico-chemical corrosion) composite, but also to use it as a grounded protective screen to drain leakage currents from the structure, thus protecting it from both corrosion and electrocorrosion destruction.
Constraints on the Formation of the Shiwu Porphyry Cu–Au Deposit in West Junggar, NW China: Insights from Tourmaline-Rich Igneous Rocks
Authors: Wu Chu , Wang Chengxi , Hong Tao , Xu Xingwang , Zheng Xiao , Liang Wanjuan , Sun Kefeng , Zhang Huijun , Dong Lianhui , Wang Bin
Published: April 2023

Tourmaline tends to occur in porphyry Cu–Au deposits as an alteration or gangue mineral. However, abundant primary tourmalines in miarolitic cavities or interstitially distributed with other silicate minerals have been found in the Shiwu porphyry Cu–Au deposit in West Junggar, NW China. These tourmalines are normally accompanied by pyrite and have a high affinity for Cu and Au mineralization. A combined study of the petrology, geochronology, isotope, and mineral geochemistry data of the tourmaline-rich igneous rocks and the wallrock of tourmaline-poor pyroxene diorite has been completed. The laser ablation inductively coupled plasma mass spectrometry (LA–ICP–MS) U–Pb dating of zircons from tourmaline-poor pyroxene diorite, tourmaline-rich diorite, and tourmaline-rich andesite shows the ages of the zircons to be 317.0 ± 1.0 Ma (MSWD = 0.37, n = 18), 315.8 ± 1.0 Ma (MSWD = 0.84, n = 22), and 306.4 ± 1.6 Ma (MSWD = 1.15, n = 15), respectively. The relatively low values of Hf isotopes (εHf(t) = +6.0 to +13.6) suggest that the tourmaline-poor pyroxene diorite is sourced from a mixed melt of juvenile mantle materials with old crustal components. The tourmaline-rich diorite and the tourmaline-rich andesite that contain higher εHf(t) values (ranging from +13.3 to +17.9) are mainly derived from juvenile mantle materials. In addition, the εHf(t) values in the tourmaline-poor pyroxene diorite and the tourmaline-rich diorite (+13.3 to +16.1) and andesite (+16.3 to +17.9) are gradually rising with their age evolution, which indicates that more and more mantle-derived components are joining in their formation process. This process has also been recorded in primary tourmaline growth, e.g., the EPMA profile reveals an increase in the contents of Fe and other metals and a decrease in Al contents from the inside (core) to the outside (growth zoning). Therefore, the injection of mantle-derived magma that could supply the large amount of copper and gold was critical for the formation of the Shiwu porphyry Cu–Au deposit.
Removal of Cyanide in Gold Cyanide Residues through Persulfate-Advanced Oxidation Process
Authors: Han Wenwen , Yang Hongying , Tong Linlin
Published: April 2023

The toxic cyanides in gold cyanide residues produced in the cyanidation process of gold extraction threaten environmental safety and inhibit the recovery of valuable metals. In this study, the removal of cyanide through the persulfate-advanced oxidation process was investigated, and heat activation and ultrasonic activation were tested for cyanide removal. The results showed that cyanide in cyanide residue could be removed by 2.0 wt.% potassium persulfate at pH 10.0 after 60 min reaction with a removal efficiency of 53.47%. The removal efficiency increased to 62.18% at T = 60 °C for heat activation and 74.76% with an ultrasonic power of 100% for ultrasonic activation. The cyanide content in the toxic leaching solution of the residue after the ultrasonic-activated persulfate-advanced oxidation process (3.84 mg/L) reached the national standard of China. Two kinds of free radical scavengers, tert-butanol and methanol, were used to investigate the generation of free radicals. The results showed that both SO4•− and HO• were produced and accelerated the oxidation of cyanide, and HO• played a major role under alkaline conditions. According to XPS analysis, the oxidation of ultrasonic-activated persulfate focused on cyanide removal rather than pyrite in cyanide residue. More cyanides were transferred from the cyanide residue to the liquid phase, leading to the high efficiency of ultrasonic activation. The ultrasonic-activated persulfate-advanced oxidation process has potential application prospects for the treatment of gold cyanide residues.
Pretreatment of Bituminous Coal By-Products for the Hydrometallurgical Extraction of Rare Earth Elements
Authors: Gupta Tushar , Nawab Ahmad , Honaker Rick
Published: April 2023

Low-temperature plasma (LTP) oxidation has been widely used to study the mineralogy of the mineral matter existing in coal sources. The current study investigated the potential of LTP oxidation as a pre-treatment method to improve rare earth element (REE) leachability from coal and its by-products. Representative density-fractionated samples of Baker and Fire Clay coarse refuse seam materials were ground to a top size of 180 µm and subjected to low-temperature plasma oxidation. Subsequently, the treated samples were leached at 1% w/v solids concentration and 75 °C for 5 h using (i) de-ionized (DI) water, (ii) 0.1 mol/L of ammonium sulfate, and (iii) 1.2 mol/L of sulfuric acid. It was determined that LTP treatment improved REE leaching characteristics, especially the leaching of heavy REEs (HREE), existing in the lighter density fractions of the Baker seam coarse refuse material. For instance, the HREE recovery for the 1.6 specific gravity (SG) float fraction increased from 8% to 33% using 0.1 mol/L of ammonium sulfate solution after 32 h of LTP treatment. This finding indicated that HREEs associated with the organic matter were released by the LTP treatment and adsorbed onto the surfaces of highly negative charged mineral matter and was exchanged with ammonium to allow their recovery. Similarly, when using 1.2 mol/L of sulfuric acid, the HREE recovery increased from 23% to 53% for the 1.6 SG float fraction. Interestingly, LTP oxidation did not provide significant improvement in REE recovery from the 2.2 sink density fractions, which was likely due to its lower organic content. No significant benefits were observed when treating the Fire Clay coarse refuse material, which was likely due to the lack of organic affinity and the difficult-to-leach REE minerals associated with the coal source such as monazite, xenotime, and zircon. Conversely, high-temperature oxidation within a temperature range of 600–750 °C significantly improved REE leaching characteristics for both coal sources. Improvement in REE recovery was due to decarbonization of the material, clay dehydroxylation and subsequent conversion of liberated REE-bearing minerals into a more leachable form. However, increasing the temperature above 800 °C decreased REE recovery due to the conversion of meta-kaolinite into mullite, which is chemically stable.
Proteases as Tools for Modulating the Antioxidant Activity and Functionality of the Spent Brewer’s Yeast Proteins
Authors: Dumitrașcu Loredana , Lanciu Dorofte Andreea , Grigore-Gurgu Leontina , Aprodu Iuliana
Published: April 2023

The functionality of the peptides obtained through enzymatic hydrolysis of spent brewer’s yeast was investigated. Hydrolysis was carried out for 4–67 h with bromelain, neutrase and trypsin. The resulting hydrolysates were characterized in terms of physical-chemical, antioxidant and techno-functional properties. The solid residues and soluble protein contents increased with the hydrolysis time, the highest values being measured in samples hydrolyzed with neutrase. Regardless of the hydrolysis time, the maximum degree of hydrolysis was measured in the sample hydrolyzed with neutrase, while the lowest was in the sample hydrolyzed with trypsin. The protein hydrolysate obtained with neutrase exhibited the highest DPPH radical scavenging activity (116.9 ± 2.9 μM TE/g dw), followed by the sample hydrolyzed with trypsin (102.8 ± 2.7 μM TE/g dw). Upon ultrafiltration, the fraction of low molecular weight peptides (<3 kDa) released by bromelain presented the highest antioxidant activity (50.06 ± 0.39 μM TE/g dw). The enzymes influenced the foaming properties and the emulsions-forming ability of the hydrolysates. The trypsin ensured the obtaining of proteins hydrolysate with the highest foam overrun and stability. The emulsions based on hydrolysates obtained with neutrase exhibited the highest viscosity at a shear rate over 10 s−1. These results indicate that the investigated proteases are suitable for modulating the overall functionality of the yeast proteins.
A Computational Evaluation of the Steric and Electronic Contributions in Stereoselective Olefin Polymerization with Pyridylamido-Type Catalysts
Authors: D’Anania Olga , De Rosa Claudio , Talarico Giovanni
Published: April 2023

A density functional theory (DFT) study combined with the steric maps of buried volume (%VBur) as molecular descriptors and an energy decomposition analysis through the ASM (activation strain model)–NEDA (natural energy decomposition analysis) approach were applied to investigate the origins of stereoselectivity for propene polymerization promoted by pyridylamido-type nonmetallocene systems. The relationships between the fine tuning of the ligand and the propene stereoregularity were rationalized (e.g., the metallacycle size, chemical nature of the bridge, and substituents at the ortho-position on the aniline moieties). The DFT calculations and %VBur steric maps reproduced the experimental trend: substituents on the bridge and on the ortho-positions of aniline fragments enhance the stereoselectivity. The ASM–NEDA analysis enabled the separation of the steric and electronic effects and revealed how subtle ligand modification may affect the stereoselectivity of the process.
Anti-COVID-19 Potential of Ellagic Acid and Polyphenols of Punica granatum L.
Authors: Alexova Ralitza , Alexandrova Simona , Dragomanova Stela , Kalfin Reni , Solak Ayten , Mehan Sidharth , Petralia Maria Cristina , Fagone Paolo , Mangano Katia , Nicoletti Ferdinando , Tancheva Lyubka
Published: April 2023

Pomegranate (Punica granatum L.) is a rich source of polyphenols, including ellagitannins and ellagic acid. The plant is used in traditional medicine, and its purified components can provide anti-inflammatory and antioxidant activity and support of host defenses during viral infection and recovery from disease. Current data show that pomegranate polyphenol extract and its ellagitannin components and metabolites exert their beneficial effects by controlling immune cell infiltration, regulating the cytokine secretion and reactive oxygen and nitrogen species production, and by modulating the activity of the NFκB pathway. In vitro, pomegranate extracts and ellagitannins interact with and inhibit the infectivity of a range of viruses, including SARS-CoV-2. In silico docking studies show that ellagitannins bind to several SARS-CoV-2 and human proteins, including a number of proteases. This warrants further exploration of polyphenol–viral and polyphenol–host interactions in in vitro and in vivo studies. Pomegranate extracts, ellagitannins and ellagic acid are promising agents to target the SARS-CoV-2 virus and to restrict the host inflammatory response to viral infections, as well as to supplement the depleted host antioxidant levels during the stage of recovery from COVID-19.
Synthesis and Evaluation of Fluorine-18-Labeled L-Rhamnose Derivatives
Authors: Zhang Xiang , Basuli Falguni , Shi Zhen-Dan , Shah Swati , Shi Jianfeng , Mitchell Amelia , Lai Jianhao , Wang Zeping , Hammoud Dima A. , Swenson Rolf E.
Published: April 2023

The use of radiolabeled glucose for PET imaging resulted in the most commonly used tracer in the clinic, 2-deoxy-2-[18F]fluoroglucose (FDG). More recently, other radiolabeled sugars have been reported for various applications, including imaging tumors and infections. Therefore, in this study, we developed a series of fluorine-18-labeled L-rhamnose derivatives as potential PET tracers of various fungal and bacterial strains. Acetyl-protected triflate precursors of rhamnose were prepared and radiolabeled with fluorine-18 followed by hydrolysis to produce L-deoxy [18F]fluororhamnose. The overall radiochemical yield was 7–27% in a 90 min synthesis time with a radiochemical purity of 95%. In vivo biodistribution of the ligands using PET imaging showed that 2-deoxy-2-[18F]fluoro-L-rhamnose is stable for at least up to 60 min in mice and eliminated via renal clearance. The tracer also exhibited minimal tissue or skeletal uptake in healthy mice resulting in a low background signal.
Computational Analysis of Histamine Protonation Effects on H1R Binding
Authors: Conrad Marcus , Horn Anselm H. C. , Sticht Heinrich
Published: April 2023

Despite numerous studies investigating histamine and its receptors, the impact of histamine protonation states on binding to the histamine H1-receptor (H1R) has remained elusive. Therefore, we assessed the influence of different histamine tautomers (τ-tautomer, π-tautomer) and charge states (mono- vs. dicationic) on the interaction with the ternary histamine-H1R-Gq complex. In atomistic molecular dynamics simulations, the τ-tautomer formed stable interactions with the receptor, while the π-tautomer induced a rotation of the histamine ring by 180° and formed only weaker hydrogen bonding interactions. This suggests that the τ-tautomer is more relevant for stabilization of the active ternary histamine-H1R-Gq complex. In addition to the two monocationic tautomers, the binding of dicationic histamine was investigated, whose interaction with the H1R had been observed in a previous experimental study. Our simulations showed that the dication is less compatible with the ternary histamine-H1R-Gq complex and rather induces an inactive conformation in the absence of the Gq protein. Our data thus indicate that the charge state of histamine critically affects its interactions with the H1R. Ultimately these findings might have implications for the future development of new ligands that stabilize distinct H1R activation states.
“Noncovalent Interaction”: A Chemical Misnomer That Inhibits Proper Understanding of Hydrogen Bonding, Rotation Barriers, and Other Topics
Authors: Weinhold Frank
Published: April 2023

We discuss the problematic terminology of “noncovalent interactions” as commonly applied to hydrogen bonds, rotation barriers, steric repulsions, and other stereoelectronic phenomena. Although categorization as “noncovalent” seems to justify classical-type pedagogical rationalizations, we show that these phenomena are irreducible corollaries of the same orbital-level conceptions of electronic covalency and resonance that govern all chemical bonding phenomena. Retention of such nomenclature is pedagogically misleading in supporting superficial dipole–dipole and related “simple, neat, and wrong” conceptions as well as perpetuating inappropriate bifurcation of the introductory chemistry curriculum into distinct “covalent” vs. “noncovalent” modules. If retained at all, the line of dichotomization between “covalent” and “noncovalent” interaction should be re-drawn beyond the range of quantal exchange effects (roughly, at the contact boundary of empirical van der Waals radii) to better unify the pedagogy of molecular and supramolecular bonding phenomena.
pH-Sensitive Gold Nanorods for Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) Delivery and DNA-Binding Studies
Authors: Zygouri Eleni , Bekiari Vlasoula , Malis Georgios , Karamanos Nikos K. , Koutsakis Christos , Psomas George , Tangoulis Vassilis
Published: April 2023

A facile experimental protocol for the synthesis of poly(ethylene glycol)-modified (PEGylated) gold nanorods (AuNRs@PEG) is presented as well as an effective drug loading procedure using the non-steroidal anti-inflammatory drug (NSAID) naproxen (NAP). The interaction of AuNRs@PEG and drug-loaded AuNRs (AuNRs@PEG@NAP) with calf-thymus DNA was studied at a diverse temperature revealing different interaction modes; AuNRs@PEG may interact via groove-binding and AuNRs@PEG@NAP may intercalate to DNA-bases. The cleavage activity of the gold nanoparticles for supercoiled circular pBR322 plasmid DNA was studied by gel electrophoresis while their affinity for human and bovine serum albumins was also evaluated. Drug-release studies revealed a pH-sensitive behavior with a release up to a maximum of 24% and 33% NAP within the first 180 min at pH = 4.2 and 6.8, respectively. The cytotoxicity of AuNRs@PEG and AuNRs@PEG@NAP was evaluated against MCF-7 and MDA-MB-231 breast cancer cell lines. The development of AuNRs as an efficient non-steroidal anti-inflammatory drugs (NSAIDs) delivery system for chemotherapy is still in its infancy. The present work can shed light and inspire other research groups to work in this direction.
Stilbenes, a Versatile Class of Natural Metabolites for Inflammation—An Overview
Authors: Al-Khayri Jameel M. , Mascarenhas Roseanne , Harish Himanshu Madapur , Gowda Yashwanth , Lakshmaiah Vasantha Veerappa , Nagella Praveen , Al-Mssallem Muneera Qassim , Alessa Fatima Mohammed , Almaghasla Mustafa Ibrahim , Rezk Adel Abdel-Sabour
Published: April 2023

Stilbenes are polyphenolic allelochemicals synthesized by plants, especially grapes, peanuts, rhubarb, berries, etc., to defend themselves under stressful conditions. They are now exploited in medicine for their antioxidant, anti-proliferative and anti-inflammatory properties. Inflammation is the immune system’s response to invading bacteria, toxic chemicals or even nutrient-deprived conditions. It is characterized by the release of cytokines which can wreak havoc on healthy tissues, worsening the disease condition. Stilbenes modulate NF-κB, MAPK and JAK/STAT pathways, and reduce the transcription of inflammatory factors which result in maintenance of homeostatic conditions. Resveratrol, the most studied stilbene, lowers the Michaelis constant of SIRT1, and occupies the substrate binding pocket. Gigantol interferes with the complement system. Besides these, oxyresveratrol, pterostilbene, polydatin, viniferins, etc., are front runners as drug candidates due to their diverse effects from different functional groups that affect bioavailability and molecular interactions. However, they each have different thresholds for toxicity to various cells of the human body, and thus a careful review of their properties must be conducted. In animal models of autoinflammatory diseases, the mode of application of stilbenes is important to their absorption and curative effects, as seen with topical and microemulsion gel methods. This review covers the diversity seen among stilbenes in the plant kingdom and their mechanism of action on the different inflammatory pathways. In detail, macrophages’ contribution to inflamed conditions in the liver, the cardiac, connective and neural tissues, in the nephrons, intestine, lungs and in myriad other body cells is explored, along with detailed explanation on how stilbenes alleviate the symptoms specific to body site. A section on the bioavailability of stilbenes is included for understanding the limitations of the natural compounds as directly used drugs due to their rapid metabolism. Current delivery mechanisms include sulphonamides, or using specially designed synthetic drugs. It is hoped that further research may be fueled by this comprehensive work that makes a compelling argument for the exploitation of these compounds in medicine.
Effects of Gas Type, Oil, Salts and Detergent on Formation and Stability of Air and Carbon Dioxide Bubbles Produced by Using a Nanobubble Generator
Authors: Zhou Kaiyu , Maugard Vincent , Zhang Wenming , Zhou Joe , Zhang Xuehua
Published: April 2023

Recent developments in ultrafine bubble generation have opened up new possibilities for applications in various fields. Herein, we investigated how substances in water affect the size distribution and stability of microbubbles generated by a common nanobubble generator. By combining light scattering techniques with optical microscopy and high-speed imaging, we were able to track the evolution of microbubbles over time during and after bubble generation. Our results showed that air injection generated a higher number of microbubbles (<10 μm) than CO2 injection. Increasing detergent concentration led to a rapid increase in the number of microbubbles generated by both air and CO2 injection and the intensity signal detected by dynamic light scattering (DLS) slightly increased. This suggested that surface-active molecules may inhibit the growth and coalescence of bubbles. In contrast, we found that salts (NaCl and Na2CO3) in water did not significantly affect the number or size distribution of bubbles. Interestingly, the presence of oil in water increased the intensity signal and we observed that the bubbles were coated with an oil layer. This may contribute to the stability of bubbles. Overall, our study sheds light on the effects of common impurities on bubble generation and provides insights for analyzing dispersed bubbles in bulk.
Reconstruction-Induced φ0 Josephson Effect in Quantum Spin Hall Constrictions
Authors: Vigliotti Lucia , Cavaliere Fabio , Passetti Giacomo , Sassetti Maura , Traverso Ziani Niccolò
Published: April 2023

The simultaneous breaking of time-reversal and inversion symmetry, in connection to superconductivity, leads to transport properties with disrupting scientific and technological potential. Indeed, the anomalous Josephson effect and the superconducting-diode effect hold promises to enlarge the technological applications of superconductors and nanostructures in general. In this context, the system we theoretically analyze is a Josephson junction (JJ) with coupled reconstructed topological channels as a link; such channels are at the edges of a two-dimensional topological insulator (2DTI). We find a robust φ0 Josephson effect without requiring the presence of external magnetic fields. Our results, which rely on a fully analytical analysis, are substantiated by means of symmetry arguments: Our system breaks both time-reversal symmetry and inversion symmetry. Moreover, the anomalous current increases as a function of temperature. We interpret this surprising temperature dependence by means of simple qualitative arguments based on Fermi’s golden rule.
Impacts of Random Atomic Defects on Critical Buckling Stress of Graphene under Different Boundary Conditions
Authors: Shi Jiajia , Chu Liu , Yu Zhengyu , Souza de Cursi Eduardo
Published: April 2023

Buckled graphene has potential applications in energy harvest, storage, conversion, and hydrogen storage. The investigation and quantification analysis of the random porosity in buckled graphene not only contributes to the performance reliability evaluation, but it also provides important references for artificial functionalization. This paper proposes a stochastic finite element model to quantify the randomly distributed porosities in pristine graphene. The Monte Carlo stochastic sampling process is combined with finite element computation to simulate the mechanical property of buckled graphene. Different boundary conditions are considered, and the corresponding results are compared. The impacts of random porosities on the buckling patterns are recorded and analyzed. Based on the large sampling space provided by the stochastic finite element model, the discrepancies caused by the number of random porosities are discussed. The possibility of strengthening effects in critical buckling stress is tracked in the large sampling space. The distinguishable interval ranges of probability density distribution for the relative variation of the critical buckling stress prove the promising potential of artificial control by the atomic vacancy amounts. In addition, the approximated Gaussian density distribution of critical buckling stress demonstrates the stochastic sampling efficiency by the Monte Carlo method and the artificial controllability of porous graphene. The results of this work provide new ideas for understanding the random porosities in buckled graphene and provide a basis for artificial functionalization through porosity controlling.
The Influence of the Size of BN NSs on Silkworm Development and Tissue Microstructure
Authors: Andoh Vivian , Liu Haiyan , Chen Liang , Ma Lin , Chen Keping
Published: April 2023

Boron nitride nanosheets (BN NSs) have emerged as promising materials in a wide range of biomedical applications. Despite the extensive studies on these bio-nano interfacial systems, one critical concern is their toxicity, which is affected by a variety of factors, including size. This study aimed at assessing the relationship between BN NSs size and toxicity. Two silkworm strains (qiufeng × baiyu and Nistari 7019) were used as model organisms to investigate the effect of different sizes of BN NSs (BN NSs-1, thickness of 41.5 nm and diameter of 270.7 nm; BN NSs-2, thickness of 48.2 nm and diameter of 562.2 nm) on silkworm mortality, growth, cocoon weight, and tissue microstructure. The findings show that exposure to BN NSs in this work has no lethal adverse effects on silkworm growth or tissue microstructure. BN NSs have a higher effect on the growth rate of qiufeng × baiyu compared to Nistari 7019, demonstrating that the same treatment does not favorably affect the Nistari 7019 strain, as there is no significant increase in cocoon weight. Overall, the study suggests that the sizes of BN NSs employed in this study are relatively safe and have less negative impact on silkworms. This offers significant insights into the effect of BN NSs size, a crucial factor to consider for their safe use in biomedical applications.
Enhancing Visible Light Photocatalytic Degradation of Bisphenol A Using BiOI/Bi2MoO6 Heterostructures
Authors: Núñez Magaly Y. Nava , Rehlaender Moisés Ávila , Martínez-de la Cruz Azael , Susarrey-Arce Arturo , Cuevas-Muñiz Francisco Mherande , Sánchez-Domínguez Margarita , Lara-Ceniceros Tania E. , Bonilla-Cruz José , Zapata Alejandro Arizpe , Hurtado Patricia Cerda , Pérez-Rodríguez Michael , Orozco Aldo Ramírez , González Lucy T. , Longoria-Rodríguez Francisco Enrique
Published: April 2023

With the growing population, access to clean water is one of the 21st-century world’s challenges. For this reason, different strategies to reduce pollutants in water using renewable energy sources should be exploited. Photocatalysts with extended visible light harvesting are an interesting route to degrade harmful molecules utilized in plastics, as is the case of Bisphenol A (BPA). This work uses a microwave-assisted route for the synthesis of two photocatalysts (BiOI and Bi2MoO6). Then, BiOI/Bi2MoO6 heterostructures of varied ratios were produced using the same synthetic routes. The BiOI/Bi2MoO6 with a flower-like shape exhibited high photocatalytic activity for BPA degradation compared to the individual BiOI and Bi2MoO6. The high photocatalytic activity was attributed to the matching electronic band structures and the interfacial contact between BiOI and Bi2MoO6, which could enhance the separation of photo-generated charges. Electrochemical, optical, structural, and chemical characterization demonstrated that it forms a BiOI/Bi2MoO6 p-n heterojunction. The free radical scavenging studies showed that superoxide radicals (O2•−) and holes (h+) were the main reactive species, while hydroxyl radical (•OH) generation was negligible during the photocatalytic degradation of BPA. The results can potentiate the application of the microwave synthesis of photocatalytic materials.
The Facile Synthesis of Hollow CuS Microspheres Assembled from Nanosheets for Li-Ion Storage and Photocatalytic Applications
Authors: Zhao Yiyang , Shao Yonghui , Chen Hao , Luo Xinwen , Liu Xiaodi
Published: April 2023

Herein, well-defined hollow CuS microspheres assembled from nanosheets were successfully synthesized through a facile solvothermal method. Hollow CuS microspheres have an average diameter of 1.5 μm; moreover, the primary CuS nanosheets have an ultrathin thickness of about 10 nm and are bound by {0001} polar facets. When used as anodes for lithium-ion batteries (LIBs), hollow CuS microspheres exhibit excellent electrochemical properties, including a large discharge capacity (610.1 mAh g−1 at 0.5 C), an excellent rate capability (207.6 and 143.4 mAh g−1 at 1 and 5 C), and a superior cyclic stability (196.3 mAh g−1 at 1 C after 500 cycles). When used as photocatalysts for Rhodamine B (RhB), hollow CuS microspheres can degrade more than 99% of the initial RhB within 21 min. These excellent Li-ion storage properties and photocatalytical performances are attributed to their unique hierarchical hollow structure.