bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Al Layer Thickness on the Bonding and Mechanical Behavior of a Mg-(Al-)Ti Laminated Sheet Prepared by Hot-Rolling after Differential Preheating Treatment
Authors: Luo Wenbo , Feng Yunzhe , Xue Zhiyong , Kong Qinke , Han Xiuzhu
Published: April 2022

Mg-(Al-)Ti laminated sheets with large bonding interfaces were prepared by a differential temperature hot-rolling process, in which the preheating treatment of Ti was 25–100 °C higher than that of Mg. The rolled sheets contained different Al layer thicknesses (≤0.05 mm), and the thickness of the diffused region at the interface of 3–7 μm was formed by rolling at 175 °C. The interfaces were the solid-solution regions of Mg(Al) and Ti(Al), and no intermetallic compounds were generated during both the rolling process and annealing treatment. The hardness of the interfaces was 16–30% greater than that of the Mg matrix and Ti matrix. The results of mechanical tests displayed that the Mg-(Al-)Ti sheets exhibited higher strength and elastic modulus compared to those of the rolled AZ31B sheet. Their UTS and YTS were about 223–460 MPa and 303–442 MPa, respectively, with an elongation of 0.04–0.17 and high elastic modulus of 52–68 GPa. The Mg-Ti (containing about 62 at.% Mg) rolled sheet exhibited the most excellent strength. The UTS and YTS were about 460 MPa and 442 MPa, with an elongation of 0.04 and elastic modulus of 61.5 GPa. Additionally, Mg-Ti sheets with thin Ti thickness possessed a higher work-hardening rate (n), as well as hardening rate, than the rolled Mg-Al-Ti sheets. This is because fractured Ti pieces around the interfaces have a significant strengthening effect. This study provides a simple method for fabricating Mg-(Al-)Ti sheets with high elastic modulus.
Effect of Heat Treatments on the Corrosion Resistance of a High Strength Mg-Gd-Y-Zn-Zr Alloy
Authors: Xu Hang , Li Yuan , Wu Luoyi , Jiang Fulin , Fu Dingfa , Teng Jie , Zhang Hui
Published: April 2022

Magnesium-rare earth (Mg-Re) alloys are very promising structural materials in lightweight industries, while the poor corrosion resistance limits their widespread application. In this work, to provide insights into the functions of precipitate characteristics on the corrosion behaviors of Mg-Re alloys, the influence of heat treatments on the corrosion behavior of Mg-11.46Gd-4.08Y-2.09Zn-0.56Zr alloy was investigated via an immersion test, electrochemical experiment and scanning electron microscope (SEM). The results showed that the corrosion rate of Mg-11.46Gd-4.08Y-2.09Zn-0.56Zr alloy specimens decreased by 17.58% and 20.44% after T5 and T6 heat treatment, respectively. In the heat-treated specimens, the corrosion did not extend further into the matrix but formed fine corrosion grooves along the extrusion direction. The improved homogeneity reduced the residual stress and the β’ precipitate introduced as a corrosion barrier after T5 and T6 heat treatment reduced the corrosion rate of the studied Mg alloy. In addition, the volume fraction of the long-period stacking-ordered (LPSO) phase decreased after heat treatment, which effectively reduced galvanic corrosion and enhanced the protective effect on the Mg matrix.
Increasing Bending Performance of Soft Actuator by Silicon Rubbers of Multiple Hardness
Authors: Jing Xishuang , Chen Siyu , Zhang Chengyang , Xie Fubao
Published: April 2022

In this study, a method for fabricating actuators made of various silicone materials is proposed to improve the flexural performance of soft-body actuators. Specifically, the redundant deformation part of the soft actuator was replaced with a material with higher hardness to limit the redundant deformation of the soft actuator. Materials with lower hardness were used to produce the main deformation part of the soft actuator, so that the soft body actuator could perform greater bending under the same air pressure and create a greater bending force. In addition, the fabricated actuator was divided into three regions in this study: the periphery of the chamber, the chamber wall (the main curved part), and the bottom surface of the actuator. The impact on the overall performance of soft-body actuators when using silicone materials with different hardness in these three regions was explored in this study. According to the idea of the multi-hardness silicone structure, an actuator with seven chambers was fabricated, and the performance of the actuator was improved by 90.72% compared with the uniform material actuator.
Magnetic Field Effect on the Oxidation of Unsaturated Compounds by Molecular Oxygen
Authors: Pliss Evgenii M. , Soloviev Mikhail E.
Published: April 2022

A quantum-chemical analysis of the effect of a constant magnetic field on radical formation in the processes of chain oxidation of organic compounds by molecular oxygen is presented. The calculation of the total electronic energies and thermodynamic functions of the compounds involved in the reactions was performed by the density functional method with the hybrid exchange-correlation functional of Becke, Lee, Yang and Parr DFT B3LYP/6-311G** using the NWChem software package. The effect of the magnetic field on the individual stages of chain oxidation is associated with the evolution of radical pairs. It is assumed that the dipole–dipole interaction in a radical pair is not averaged by the diffusion of radicals and should be taken into account. To a large extent, the magnetic field effect (MFE) value is influenced by the ratio between the relaxation time of the oscillatory-excited state in the radical pair (tvib) and the relaxation time of the inter-combination transitions (tst). Although the developed technique refers to liquid-phase reactions, it can be used to study the MFE for oxidation of biologically significant compounds in multiphase systems, such as micelles, liposomes and membranes.
Adaptive Sliding-Mode Controller for Flyback-Based PV Systems Featuring Constant Switching Frequency
Authors: Ramos-Paja Carlos Andres , Montoya Oscar Danilo , Grisales-Noreña Luis Fernando
Published: April 2022

This paper proposes a sliding-mode controller to ensure both the global stability and maximum power generation of a photovoltaic system based on a flyback converter. The controller is based on an adaptive sliding-surface, which is designed to impose a constant frequency to the switching converter, thus simplifying the selection of both the passive and active elements of the device. Moreover, the controller stability is analyzed using the transversality, reachability and equivalent control conditions. The solution also includes an auto-tuning process for the parameters of the perturb and observe algorithm, which are calculated to ensure the global stability of the sliding-mode controller, thus ensuring the PV system stability. Finally, the performance of the complete solution is verified using detailed circuital simulations of a realistic application case.
Enhanced Fuzzy Elephant Herding Optimization-Based OTSU Segmentation and Deep Learning for Alzheimer’s Disease Diagnosis
Authors: Alhassan Afnan M. ,   The Alzheimer’s Disease Neuroimaging Initiative,   The Australian Imaging Biomarkers and Lifestyle Flagship Study of Ageing
Published: April 2022

Several neurological illnesses and diseased sites have been studied, along with the anatomical framework of the brain, using structural MRI (sMRI). It is critical to diagnose Alzheimer’s disease (AD) patients in a timely manner to implement preventative treatments. The segmentation of brain anatomy and categorization of AD have received increased attention since they can deliver good findings spanning a vast range of information. The first research gap considered in this work is the real-time efficiency of OTSU segmentation, which is not high, despite its simplicity and good accuracy. A second issue is that feature extraction could be automated by implementing deep learning techniques. To improve picture segmentation’s real-timeliness, enhanced fuzzy elephant herding optimization (EFEHO) was used for OTSU segmentation, and named EFEHO-OTSU. The main contribution of this work is twofold. One is utilizing EFEHO in the recommended technique to seek the optimal segmentation threshold for the OTSU method. Second, dual attention multi-instance deep learning network (DA-MIDL) is recommended for the timely diagnosis of AD and its prodromal phase, mild cognitive impairment (MCI). Tests show that this technique converges faster and takes less time than the classic OTSU approach without reducing segmentation performance. This study develops a valuable tool for quick picture segmentation with good real-time efficiency. Compared to numerous conventional techniques, the suggested study attains improved categorization performance regarding accuracy and transferability.
One-Step Fabrication of Novel Polyethersulfone-Based Composite Electrospun Nanofiber Membranes for Food Industry Wastewater Treatment
Authors: Pervez Md. Nahid , Talukder Md Eman , Mishu Monira Rahman , Buonerba Antonio , Del Gaudio Pasquale , Stylios George K , Hasan Shadi W. , Zhao Yaping , Cai Yingjie , Figoli Alberto , Zarra Tiziano , Belgiorno Vincenzo , Song Hongchen , Naddeo Vincenzo
Published: April 2022

Using an environmentally friendly approach for eliminating methylene blue from an aqueous solution, the authors developed a unique electrospun nanofiber membrane made of a combination of polyethersulfone and hydroxypropyl cellulose (PES/HPC). SEM results confirmed the formation of a uniformly sized nanofiber membrane with an ultrathin diameter of 168.5 nm (for PES/HPC) and 261.5 nm (for pristine PES), which can be correlated by observing the absorption peaks in FTIR spectra and their amorphous/crystalline phases in the XRD pattern. Additionally, TGA analysis indicated that the addition of HPC plays a role in modulating their thermal stability. Moreover, the blended nanofiber membrane exhibited better mechanical strength and good hydrophilicity (measured by the contact angle). The highest adsorption capacity was achieved at a neutral pH under room temperature (259.74 mg/g), and the pseudo-second-order model was found to be accurate. In accordance with the Langmuir fitted model and MB adsorption data, it was revealed that the adsorption process occurred in a monolayer form on the membrane surface. The adsorption capacity of the MB was affected by the presence of various concentrations of NaCl (0.1–0.5 M). The satisfactory reusability of the PES/HPC nanofiber membrane was revealed for up to five cycles. According to the mechanism given for the adsorption process, the electrostatic attraction was shown to be the most dominant in increasing the adsorption capacity. Based on these findings, it can be concluded that this unique membrane may be used for wastewater treatment operations with high efficiency and performance.
Controlling Air Bubble Formation Using Hydrophilic Microfiltration Diffuser for C. vulgaris Cultivation
Authors: Shafie Siti Nur Alwani , Shen Wong Yoong , Jaymon Jc Jcy , Nordin Nik Abdul Hadi Md , Mohamednour Abdelslam Elsir Elsiddig , Bilad Muhammad Roil , Kee Lam Man , Matsuura Takeshi , Othman Mohd Hafiz Dzarfan , Jaafar Juhana , Ismail Ahmad Fauzi
Published: April 2022

In this project, a commercial polytetrafluoroethylene (PTFE) membrane was coated with a thin layer of polyether block amide (PEBAX) via vacuum filtration to improve hydrophilicity and to study the bubble formation. Two parameters, namely PEBAX concentration (of 0–1.5 wt%) and air flow rate (of 0.1–50 mL/s), were varied and their effects on the bubble size formation were investigated. The results show that the PEBAX coating reduced the minimum membrane pore size from 0.46 μm without coating (hereafter called PEBAX0) to 0.25 μm for the membrane coated with 1.5wt% of PEBAX (hereafter called PEBAX1.5). The presence of polar functional groups (N-H and C=O) in PEBAX greatly improved the membrane hydrophilicity from 118° for PEBAX0 to 43.66° for PEBAX1.5. At an air flow rate of 43 mL/s, the equivalent bubble diameter size decreased from 2.71 ± 0.14 cm for PEBAX0 to 1.51 ± 0.02 cm for PEBAX1.5. At the same air flow rate, the frequency of bubble formation increased six times while the effective gas–liquid contact area increased from 47.96 cm2/s to 85.6 cm2/s. The improved growth of C. vulgaris from 0.6 g/L to 1.3 g/L for PEBAX1.5 also shows the potential of the PEBAX surface coating porous membrane as an air sparger.
Polymer Electrolytes for Lithium-Ion Batteries Studied by NMR Techniques
Authors: Volkov Vitaly I. , Yarmolenko Olga V. , Chernyak Alexander V. , Slesarenko Nikita A. , Avilova Irina A. , Baymuratova Guzaliya R. , Yudina Alena V.
Published: April 2022

This review is devoted to different types of novel polymer electrolytes for lithium power sources developed during the last decade. In the first part, the compositions and conductivity of various polymer electrolytes are considered. The second part contains NMR applications to the ion transport mechanism. Polymer electrolytes prevail over liquid electrolytes because of their exploitation safety and wider working temperature ranges. The gel electrolytes are mainly attractive. The systems based on polyethylene oxide, poly(vinylidene fluoride-co-hexafluoropropylene), poly(ethylene glycol) diacrylate, etc., modified by nanoparticle (TiO2, SiO2, etc.) additives and ionic liquids are considered in detail. NMR techniques such as high-resolution NMR, solid-state NMR, magic angle spinning (MAS) NMR, NMR relaxation, and pulsed-field gradient NMR applications are discussed. 1H, 7Li, and 19F NMR methods applied to polymer electrolytes are considered. Primary attention is given to the revelation of the ion transport mechanism. A nanochannel structure, compositions of ion complexes, and mobilities of cations and anions studied by NMR, quantum-chemical, and ionic conductivity methods are discussed.
Intelligent Analysis for Safety-Influencing Factors of Prestressed Steel Structures Based on Digital Twins and Random Forest
Authors: Zhu Haoliang , Wang Yousong
Published: April 2022

The structure of a prestressed steel structure is complex, which can result in insufficient control accuracy and the low efficiency of the structural safety. The traditional analysis method only obtains the mechanical parameters of the structure and it cannot obtain the key factors that affect the structural safety. In order to improve the intelligence level of the structural safety performance analysis, this study proposes an intelligent analysis for the safety-influencing factors of prestressed steel structures that is based on digital twins (DTs) and random forest (RF). Firstly, the high-precision twin modeling is carried out by the weighted average method. The design parameters and the mechanical parameters of the structure are extracted in real time in the twin model, and the parameters are classified by the RF. The fusion mechanism of the DTs and RF is formed, and the intelligent analysis model of the structural safety factors is established. Driven by the analysis model, the correlation mechanism between the design parameters and the mechanical parameters is formed. The safety state of the structure is judged by the mechanical parameters, and the key design parameters that affect the various mechanical parameters are analyzed. Through the integration of the design parameters and mechanical parameters, the intelligent analysis process of the safety-influencing factors of prestressed steel structures is formed. Finally, an intelligent analysis of the importance of the safety-influencing factors is carried out with the string-supported beam structure as the test object. Driven by the integration of DTs and RF, the key design parameters that affect the various mechanical parameters are accurately obtained, which provides a basis for the intelligent control of the structural safety.
Recovery and Preparation of Potassium Fluorotantalate from High-Tantalum-Bearing Waste Slag by Pressure Alkaline Decomposition
Authors: Xie Kangde , Wei Xiuyu , Ye Longgang , Wan Mingyuan , Li Shilin , Wu Jianguo
Published: April 2022

Tantalum slag is a type of high-grade tantalum resource with great recovery value. In this paper, a low fluorine process, including alkali pressure decomposition, low-acid transformation, solvent extraction, and crystallization, is proposed to recover tantalum and prepare potassium fluotantalate. First, some tantalum slag underwent alkali pressure decomposition, and the optimal decomposition conditions were obtained under a reaction time of 2 h, oxygen partial pressure 2.5 MPa, liquid–solid ratio 4:1, basicity 40 wt.%, and temperature 200 °C. Under these conditions, the decomposition efficiencies of Ta and Nb were 93.62% and 95.42%, respectively. X-Ray diffraction (XRD) and scanning electron microscope (SEM) were used to detect the main phase of the decomposition residue and showed that it was mainly sodium tantalate. With the increase in oxygen partial pressure, the particle size of decomposition slag gradually decreases and becomes loose. Second, the alkali decomposition residue was subjected to low-acid leaching to obtain fluorine tantalate and fluorine niobate, and the leaching efficiencies of tantalum and niobium were more than 99%. Last, the low-acid leaching solution was subjected to solvent extraction and evaporative crystallization to prepare potassium fluotantalate. The results showed that the tantalum extraction rate and tantalum and niobium separation factors were above 94% and 200, respectively, and the purity of potassium fluotantalate met the requirements of commercial products. Compared with current industrial practice, the consumption of hydrofluoric acid was greatly reduced, and the recovery rate of tantalum was increased.
Predicting the Irradiation Swelling of Austenitic and Ferritic/Martensitic Steels, Based on the Coupled Model of Machine Learning and Rate Theory
Authors: Zhu Xiaohan , Li Xiaochen , Zheng Mingjie
Published: April 2022

As nuclear structural materials, austenitic and ferritic/martensitic (F/M) steels will face inevitable irradiation swelling when fulfilling a role in nuclear reactors, especially under high-dose irradiation. For this work, a coupled machine learning rate theory (ML-RT) model for the swelling of austenitic and F/M steels was developed. In this model, ML was introduced to predict the steady-state irradiation swelling onset dose (Donset), while the improved RT was developed to simulate the swelling behavior after the incubation period. More than 200 series of data on the Donset of different structures of steel were collected for the ML prediction. The coefficient of determination (R) of the results in ML is more than 0.9. In the RT, the evolutions of the dislocation loop and void were described and calculated rather than using the fitting parameters. Cascade efficiency was employed to describe the cascade process. The coupled ML-RT model was verified with the swelling data from neutron irradiation experiments for various steels. The theoretical results of the swelling peak temperatures and swelling behavior are more accurate and reasonable, compared with those from the previous RT model. Using the ML-RT model, the swelling performance of CLAM steel under neutron irradiation of up to 180 dpa was predicted. The differences between the swelling performance of austenitic steels and F/M steels were analyzed and the differences were mainly associated with the bias. These results will be helpful for evaluating the neutron irradiation swelling behavior of candidate structural materials.
Impact of Channels Aspect Ratio on the Heat Transfer in Finned Heat Sinks with Tip Clearance
Authors: Martin Elena , Valeije Alejandro , Sastre Francisco , Velazquez Angel
Published: April 2022

A 3D numerical study is used to analyze the flow topology and performance, in terms of heat transfer efficiency and required pumping power, of heat sink devices with different channel aspect-ratio in the presence of tip-clearance. Seven different channel aspect ratios AR, from 0.25 to 1.75, were analyzed. The flow Reynolds numbers Re, based on the average velocity evaluated in the device channels region, were in the range of 200 to 1000. Two different behaviors of the global Nusselt were obtained depending on the flow Reynolds number: for Re<600, the heat transfer increased with the channels aspect ratio, e.g., for Re=400, the global Nusselt number increased by 14% for configuration AR=1.75 when compared to configuration AR=0.25. For Re>600, the maximum Nusselt is obtained for the squared-channel configuration, and, for some configurations, flow destabilization to a unsteady regime appeared. For Re=700, Nusselt number reduced when compared with the squared-channel device, 11% and 2% for configurations with AR=0.25 and 1.75, respectively. Dimensionless pressure drop decreased with the aspect ratio for all cases. In the context of micro-devices, where the Reynolds number is small, these results indicate that the use of channels with high aspect-ratios is more beneficial, both in terms of thermal and dynamic efficiency.
Distribution, Sedimentology and Origin of Mineralogical Assemblages from a Continental Na-bentonite Deposit in the Cretaceous Neuquén Basin (Argentina)
Authors: Musso Telma Belén , Pettinari Gisela , Pozo Manuel , Martínez Alexis Gabriel , González Rafael
Published: April 2022

Collected samples of bentonite and associated facies from the Justina deposit of Cretaceous age (Anacleto Formation) have been studied. Facies analysis, mineralogical, and geochemical studies have been carried out using several techniques, including: XRD, FTIR, DTA-TGA, microscopy (OM, SEM-EDX), and chemical analysis. The deposit occurs in a shallow, saline lacustrine environment developed over a fluvial floodplain, with a thickness between 0.21 and 0.8 m intercalated between fine-grained siliciclastic facies. Three mineral assemblages were found. In assemblage 1, the bentonite has low content of detrital minerals and the smectite is sodic. In assemblage 2, the bentonite shows the occurrence of minor analcime and mica, slightly higher detrital mineral content and the smectite is sodic to sodic-calcic. The associated detrital facies (assemblage 3) is dominated by illite and a mixed layer of illite and calcic smectite (R0), subordinately kaolinite + chlorite, and locally low-ordered smectite. As inherited minerals are found: quartz, potassium feldspar, plagioclase, illite-mica, heavy minerals (monazite, zircon, apatite, titanomagnetite) and volcanic rock fragments (andesite, glass). Authigenic minerals are: sodium smectite, analcime, barite, celestine, gypsum, and hematite. A model for the formation of authigenic minerals is proposed, highlighting the formation of sodic smectite from the alteration of volcanic glass of trachyandesitic composition.
Physicochemical, Antioxidant and Anticancer Characteristics of Seed Oil from Three Chenopodium quinoa Genotypes
Authors: Shen Yingbin , Zheng Liyou , Peng Yao , Zhu Xucheng , Liu Fu , Yang Xinquan , Li Haimei
Published: April 2022

Chenopodium quinoa Willd. is recognized to be an excellent nutrient with high nutritional content. However, few genotypes of quinoa were analyzed, so we found a knowledge gap in the comparison of quinoa seeds of different genotypes. This study aims to compare the physicochemical, antioxidant, and anticancer properties of seed oil from three C. quinoa genotypes. Seeds of three genotypes (white, red, and black) were extracted with hexane and compared in this study. The oil yields of these quinoa seeds were 5.68–6.19% which contained predominantly polyunsaturated fatty acids (82.78–85.52%). The total tocopherol content ranged from 117.29 to 156.67 mg/kg and mainly consisted of γ-tocopherol. Total phytosterols in the three oils ranged from 9.4 to 12.2 g/kg. Black quinoa seed oil had the highest phytosterols followed by red and white quinoas. The chemical profile of quinoa seed oils paralleled by their antioxidant and anticancer activities in vitro was positively correlated with the seed coat color. Black quinoa seed oil had the best antioxidant and anti-proliferation effect on HCT 116 cells by the induction of apoptosis in a dose-dependent manner, which may play more significant roles in the chemoprevention of cancer and other diseases related to oxidative stress as a source of functional foods.
Effect of Long-Term Potato Starch Retention with Citric Acid on Its Properties
Authors: Kapelko-Żeberska Małgorzata , Meisel Marta , Buksa Krzysztof , Gryszkin Artur , Szumny Antoni , Latacz Bogna , Raszewski Bartosz , Zięba Tomasz
Published: April 2022

The present study aimed to determine changes in the properties of starch triggered by its long-lasting (1, 2, 4, 7, 10, or 14 days) retention with citric acid (5 g/100 g) at a temperature of 40 °C. The starch citrates obtained under laboratory conditions had a low degree of substitution, as confirmed via NMR and HPSEC analyses. The prolonging time of starch retention with citric acid at 40 °C contributed to its increased esterification degree (0.05–0.11 g/100 g), swelling power (30–38 g/g), and solubility in water (19–35%) as well as to decreased viscosity of the starch pastes. Starch heating with citric acid under the applied laboratory conditions did not affect the course of DSC thermal characteristics of starch pasting. The low-substituted starch citrates exhibited approximately 15% resistance to amylolysis.
A Disposable Sensor Chip Using a Paste Electrode with Surface-Imprinted Graphite Particles for Rapid and Reagentless Monitoring of Theophylline
Authors: Aaryashree  , Ohishi Tomoji , Yoshimi Yasuo
Published: April 2022

This work focuses on a carbon-based imprinted polymer composite, employed as a molecular recognition and sensing interface in fabricating a disposable electrochemical sensor. The carbon-paste electrode was made of a molecularly imprinted polymer comprising a copolymer of methacrylic acid as the functional monomer and blended crosslinking monomers of N,N′-methylenebisacrylamide, and ethylene glycol dimethacrylate, with theophylline as the template. The analytical properties of the proposed theophylline sensor were investigated, and the findings revealed an increase in differential pulse voltammetric current compared to the non-imprinted electrode. Under optimized conditions, the sensor has shown high sensitivity, high selectivity, lower detection limit (2.5 µg/mL), and satisfactory long-term stability. Further, the sensor was tested in whole bovine blood and validated without any matrix effect and cross-reactivity. Additionally, chronoamperometry of the sensor chip supported a rapid determination of THO with a short response time of 3 s. This carbon-paste electrode is highly specific for theophylline and may be applied as a drug sensor for clinical use.
Solvent Moisture-Controlled Self-Assembly of Fused Benzoimidazopyrrolopyrazines with Different Ring’s Interposition
Authors: Martynovskaya Svetlana V. , Budaev Arsalan B. , Ushakov Igor A. , Borodina Tatyana N. , Ivanov Andrey V.
Published: April 2022

This article shows that two extremely important families of fused heterocyclic assemblies, namely 6-methylbenzo[4,5]imidazo[1,2-a]pyrrolo[2,1-c]pyrazine and 5a-methyl-5a,6-dihydro-5H,12H-benzo[4,5]imidazo[1,2-a]pyrrolo[1,2-d]pyrazine, can be synthesized from only two available building blocks (N-allenylpyrrole-2-carbaldehyde and o-phenylenediamine) by controlling only one reaction parameter (water content of the medium). It should be emphasized that the latter class of compounds (with an a/d arrangement) is previously unknown. If the allene group is introduced not into the starting compound, but during the reaction (in superbase media), a heterocyclic ensemble, 5-methylbenzo[4,5]imidazo[1,2-a]pyrrolo[2,1-c]pyrazines, with a different position of the methyl group is formed.
Investigation of an Allosteric Deoxyhypusine Synthase Inhibitor in P. falciparum
Authors: Aroonsri Aiyada , Wongsombat Chayaphat , Shaw Philip , Franke Siegrid , Przyborski Jude , Kaiser Annette
Published: April 2022

The treatment of a variety of protozoal infections, in particular those causing disabling human diseases, is still hampered by a lack of drugs or increasing resistance to registered drugs. However, in recent years, remarkable progress has been achieved to combat neglected tropical diseases by sequencing the parasites’ genomes or the validation of new targets in the parasites by novel genetic manipulation techniques, leading to loss of function. The novel amino acid hypusine is a posttranslational modification (PTM) that occurs in eukaryotic initiation factor 5A (EIF5A) at a specific lysine residue. This modification occurs by two steps catalyzed by deoxyhypusine synthase (dhs) and deoxyhypusine hydroxylase (DOHH) enzymes. dhs from Plasmodium has been validated as a druggable target by small molecules and reverse genetics. Recently, the synthesis of a series of human dhs inhibitors led to 6-bromo-N-(1H-indol-4yl)-1-benzothiophene-2-carboxamide, a potent allosteric inhibitor with an IC50 value of 0.062 µM. We investigated this allosteric dhs inhibitor in Plasmodium. In vitro P. falciparum growth assays showed weak inhibition activity, with IC50 values of 46.1 µM for the Dd2 strain and 51.5 µM for the 3D7 strain, respectively. The antimalarial activity could not be attributed to the targeting of the Pfdhs gene, as shown by chemogenomic profiling with transgenically modified P. falciparum lines. Moreover, in dose-dependent enzymatic assays with purified recombinant P. falciparum dhs protein, only 45% inhibition was observed at an inhibitor dose of 0.4 µM. These data are in agreement with a homology-modeled Pfdhs, suggesting significant structural differences in the allosteric site between the human and parasite enzymes. Virtual screening of the allosteric database identified candidate ligand binding to novel binding pockets identified in P. falciparum dhs, which might foster the development of parasite-specific inhibitors.
Dicarboxylic Acid Monoesters in β- and δ-Lactam Synthesis
Authors: Ananeva Anna , Bakulina Olga , Dar’in Dmitry , Kantin Grigory , Krasavin Mikhail
Published: April 2022

A N-(2-methoxy-2-oxoethyl)-N-(phenylsulfonyl)glycine monomethyl ester of the respective dicarboxylic acid was involved in a reaction with imines promoted by acetic anhydride at an elevated temperature. Instead of the initially expected δ-lactam products of the Castagnoli–Cushman-type reaction, medicinally important 3-amino-2-azetidinones were obtained as the result of cyclization, involving a methylene group adjacent to an acid moiety. In contrast, replacing alcohol residue with hexafluoroisopropyl in the same substrate made another methylene group (adjacent to the ester moiety) more reactive to furnishing the desired δ-lactam in the Castagnoli–Cushman fashion.
Synthesis of New Spiro-Cyclopropanes Prepared by Non-Stabilized Diazoalkane Exhibiting an Extremely High Insecticidal Activity
Authors: Ben Hamadi Naoufel , Guesmi Ahlem
Published: April 2022

The synthesis of new insecticidal gem-dimethyspiro-cyclopropanes derived from pyrrolidine-2,3-dione have been described, and their biological effect against different insect species has been evaluated. The presented results demonstrate the excellent insecticidal activity of cyclopropane 5c against Aedes aegypti and Musca domestica. Cyclopropane 5c showed the quickest knockdown and the best killing against Aedes aegypti and Musca domestica compared to trans-chrysanthemic acid and pyrethrin. The biological results of the high insecticidal activity were confirmed by the results of docking. This is evident in the binding affinity obtained for cyclopropane 5c, indicating good binding with an important active amino acid residue of the 5FT3 protein.
A Record Linkage-Based Data Deduplication Framework with DataCleaner Extension
Authors: Azeroual Otmane , Jha Meena , Nikiforova Anastasija , Sha Kewei , Alsmirat Mohammad , Jha Sanjay
Published: April 2022

The data management process is characterised by a set of tasks where data quality management (DQM) is one of the core components. Data quality, however, is a multidimensional concept, where the nature of the data quality issues is very diverse. One of the most widely anticipated data quality challenges, which becomes particularly vital when data come from multiple data sources which is a typical situation in the current data-driven world, is duplicates or non-uniqueness. Even more, duplicates were recognised to be one of the key domain-specific data quality dimensions in the context of the Internet of Things (IoT) application domains, where smart grids and health dominate most. Duplicate data lead to inaccurate analyses, leading to wrong decisions, negatively affect data-driven and/or data processing activities such as the development of models, forecasts, simulations, have a negative impact on customer service, risk and crisis management, service personalisation in terms of both their accuracy and trustworthiness, decrease user adoption and satisfaction, etc. The process of determination and elimination of duplicates is known as deduplication, while the process of finding duplicates in one or more databases that refer to the same entities is known as Record Linkage. To find the duplicates, the data sets are compared with each other using similarity functions that are usually used to compare two input strings to find similarities between them, which requires quadratic time complexity. To defuse the quadratic complexity of the problem, especially in large data sources, record linkage methods, such as blocking and sorted neighbourhood, are used. In this paper, we propose a six-step record linkage deduplication framework. The operation of the framework is demonstrated on a simplified example of research data artifacts, such as publications, research projects and others of the real-world research institution representing Research Information Systems (RIS) domain. To make the proposed framework usable we integrated it into a tool that is already used in practice, by developing a prototype of an extension for the well-known DataCleaner. The framework detects and visualises duplicates thereby identifying and providing the user with identified redundancies in a user-friendly manner allowing their further elimination. By removing the redundancies, the quality of the data is improved therefore improving analyses and decision-making. This study makes a call for other researchers to take a step towards the “golden record” that can be achieved when all data quality issues are recognised and resolved, thus moving towards absolute data quality.
Explaining the Frequency Dependence of the DC-Biased Dielectric Response of Polar Nanoregions by Field-Enhanced Correlation Length
Authors: Zhang Jianwei , Du Xiaoping , Zhao Jiguang , Duan Yongsheng
Published: April 2022

Understanding the effects of polar nanoregions (PNRs) dynamics on dielectric properties is a complex question of essential importance for both fundamental studies of relaxor ferroelectrics and their applications to electro-optic devices. The frequency dependence of dielectric response to the bias electric field opens a brand new window for the study of this problem. A novel model from mesoscopic to macroscopic, revealing the relationship between the dielectric permittivity to the applied electric field, temperature, and PNRs, was established based on mean field approximation and the theory of continuum percolation, and not only validates the field-induced percolation and the relaxation time divergency at the freezing temperature, but also predicts the frequency dependence of dielectric response. Unexpectedly, the model reveals the field-enhanced correlation length results in the nonmonotonic behavior of dielectric response, and implies that the increased orientation consistency of dipolar clusters and coercive fields originated from inherent inhomogeneity slow down the relaxation time of PNR reorientation. Considering the multi-scale heterogeneity of PNRs in relaxor, we found that the increased heterogeneity degree reduces the dielectric permittivity, but changes the slope of dielectric response to the bias electric field.
A Co-Doped Carbon Dot/Silver Nanoparticle Nanocomposite-Based Fluorescence Sensor for Metformin Hydrochloride Detection
Authors: Le Thi-Hoa , Kim Ji-Hyeon , Park Sang-Joon
Published: April 2022

In this study, a fluorescence sensor based on nitrogen and phosphorus co-doped carbon dot/silver nanoparticle (NPCD/AgNP) nanocomposites was developed for metformin hydrochloride (MFH) detection. We first utilized the reducing nature of the NPCDs to prepare AgNPs from Ag+ and subsequently prepare NPCD/AgNP nanocomposites. The nanocomposite material was characterized by various methods, including electron microscopic methods (SEM and TEM), spectroscopic methods (UV-Vis, PL, FTIR, and XPS spectroscopy), light scattering (ELS), and XRD. Further, we utilized the enhanced fluorescence of the NPCDs as well as the overlap between the fluorescence emission spectrum of the NPCDs and the absorption spectrum of the AgNPs to use the NPCD/AgNP nanocomposites as an effective inner filter effect (IFE) pair for sensing MFH. The IFE between NPCDs and AgNPs in the nanocomposite material resulted in a significant quenching of the fluorescence intensity of the nanocomposites compared to that of the pure NPCDs. However, the fluorescence was recovered when MFH was introduced into the nanocomposite solution. The fluorescence intensity of the nanocomposites increased linearly as the MFH concentration increased from 2 to 100 µg/L. This detection method showed good sensitivity compared to other methods. It also showed high selectivity and high sensing potential for MFH in human serum and yielded acceptable results.
Nanoplastics and Human Health: Hazard Identification and Biointerface
Authors: Lai Hanpeng , Liu Xing , Qu Man
Published: April 2022

Nanoplastics are associated with several risks to the ecology and toxicity to humans. Nanoplastics are synthetic polymers with dimensions ranging from 1 nm to 1 μm. They are directly released to the environment or secondarily derived from plastic disintegration in the environment. Nanoplastics are widely detected in environmental samples and the food chain; therefore, their potentially toxic effects have been widely explored. In the present review, an overview of another two potential sources of nanoplastics, exposure routes to illustrate hazard identification of nanoplastics, cell internalization, and effects on intracellular target organelles are presented. In addition, challenges on the study of nanoplastics and future research areas are summarized. This paper also summarizes some approaches to eliminate or minimize the levels of nanoplastics to ensure environmental safety and improve human health.
Development of a Novel Methotrexate-Loaded Nanoemulsion for Rheumatoid Arthritis Treatment with Site-Specific Targeting Subcutaneous Delivery
Authors: Suresh Parvathy , Salem-Bekhit Mounir M. , Veedu Hafsa Palathum , Alshehri Sultan , Nair Sreeja Chandrasekhar , Bukhari Sarah I. , Viswanad Vidya , Taha Ehab I. , Sahu Ram Kumar , Ghoneim Mohammed M. , Elbagory Ibrahim
Published: April 2022

Rheumatoid arthritis (RA) is a systemic, chronic autoimmune disease that causes disability due to progressive inflammation and destruction of the tissues around the joints. Methotrexate is mainly used to prevent the progression of joint destruction and reduce the deformity. The major challenge in treating RA with methotrexate is the systemic side effects that limit dose escalation. Hence, a novel formulation of a methotrexate-loaded nanoemulsion for subcutaneous administration was developed that aims to deliver methotrexate into the system via the lymph. The methotrexate-loaded nanoemulsion was prepared by using the aqueous-titration method. The prepared nanoemulsion was investigated for particle size, surface charge, surface morphology, entrapment efficiency, DSC (differential scanning colorimetry), drug release, hemocompatibility assay, and cytotoxicity, as well as anti-arthritic and stability studies. The vesicle size, zeta potential, PDI (polydispersity index), and entrapment efficiency of the optimized nanoemulsion were 87.89 ± 2.86 nm, 35.9 ± 0.73 mV, 0.27, and 87 ± 0.25%, respectively. The DSC study showed that the crystalline methotrexate was converted to an amorphous form and the drug was fully incorporated into the vesicles. After 72 h, the optimized nanoemulsion showed a drug release of 96.77 ± 0.63%, indicating a sustained-release dosage form. Cytocompatibility testing by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide) assay on macrophage cell lines showed that the nanoemulsion was non-toxic. The formulation showed significant anti-arthritic activity compared to the marketed drug solution. In addition, the nanoemulsion containing methotrexate remained stable for three months when stored at a low temperature. Since the nanoemulsion containing methotrexate has excellent physicochemical properties and lowers systemic side effects by targeted delivery, it is a desirable technology for subcutaneous drug delivery.
Precise and Prompt Analyte Detection via Ordered Orientation of Receptor in WSe2-Based Field Effect Transistor
Authors: Zafar Muhammad Shahzad , Dastgeer Ghulam , Kalam Abul , Al-Sehemi Abdullah G. , Imran Muhammad , Kim Yong Ho , Chae Heeyeop
Published: April 2022

Field-effect transistors (FET) composed of transition metal dichalcogenide (TMDC) materials have gained huge importance as biosensors due to their added advantage of high sensitivity and moderate bandgap. However, the true potential of these biosensors highly depends upon the quality of TMDC material, as well as the orientation of receptors on their surfaces. The uncontrolled orientation of receptors and screening issues due to crossing the Debye screening length while functionalizing TMDC materials is a big challenge in this field. To address these issues, we introduce a combination of high-quality monolayer WSe2 with our designed Pyrene-based receptor moiety for its ordered orientation onto the WSe2 FET biosensor. A monolayer WSe2 sheet is utilized to fabricate an ideal FET for biosensing applications, which is characterized via Raman spectroscopy, atomic force microscopy, and electrical prob station. Our construct can sensitively detect our target protein (streptavidin) with 1 pM limit of detection within a short span of 2 min, through a one-step functionalizing process. In addition to having this ultra-fast response and high sensitivity, our biosensor can be a reliable platform for point-of-care-based diagnosis.
An Alkaline-Acid Glycerol Electrochemical Reformer for Simultaneous Production of Hydrogen and Electricity
Authors: Amorim Fernando , Crisafulli Rudy , Linares José
Published: April 2022

This study shows the results, for the first time, of an glycerol alkaline-acid electrolyzer. Such a configuration allows spontaneous operation, producing energy and hydrogen simultaneously as a result of the utilization of the neutralization and fuel chemical energy. The electroreformer—built with a 20 wt% Pd/C anode and cathode, and a Na+-pretreated Nafion® 117—can simultaneously produce hydrogen and electricity in the low current density region, whereas it operates in electrolysis mode at high current densities. In the spontaneous region, the maximum power densities range from 1.23 mW cm−2 at 30 °C to 11.9 mW cm−2 at 90 °C, with a concomitant H2 flux ranging from 0.0545 STP m−3 m−2 h−1 at 30 °C to 0.201 STP m−3 m−2 h−1 at 90 °C, due to the beneficial effect of the temperature on the performance. Furthermore, over a chronoamperometric test, the electroreformer shows a stable performance over 12 h. As a challenge, proton crossover from the cathode to the anode through the cation exchange Nafion® partially reduces the pH gradient, responsible for the extra electromotive force, thus requiring a less permeable membrane.
Recent Application of Nanomaterials to Overcome Technological Challenges of Microbial Electrolysis Cells
Authors: Kim Byeongcheol , Yang Euntae , Kim Bongkyu , Obaid M. , Jang Jae Kyung , Chae Kyu-Jung
Published: April 2022

Microbial electrolysis cells (MECs) have attracted significant interest as sustainable green hydrogen production devices because they utilize the environmentally friendly biocatalytic oxidation of organic wastes and electrochemical proton reduction with the support of relatively lower external power compared to that used by water electrolysis. However, the commercialization of MEC technology has stagnated owing to several critical technological challenges. Recently, many attempts have been made to utilize nanomaterials in MECs owing to the unique physicochemical properties of nanomaterials originating from their extremely small size (at least <100 nm in one dimension). The extraordinary properties of nanomaterials have provided great clues to overcome the technological hurdles in MECs. Nanomaterials are believed to play a crucial role in the commercialization of MECs. Thus, understanding the technological challenges of MECs, the characteristics of nanomaterials, and the employment of nanomaterials in MECs could be helpful in realizing commercial MEC technologies. Herein, the critical challenges that need to be addressed for MECs are highlighted, and then previous studies that used nanomaterials to overcome the technological difficulties of MECs are reviewed.
Intestinal Permeability in Children with Functional Gastrointestinal Disorders: The Effects of Diet
Authors: Giorgio Valentina , Margiotta Gaia , Stella Giuseppe , Di Cicco Federica , Leoni Chiara , Proli Francesco , Zampino Giuseppe , Gasbarrini Antonio , Onesimo Roberta
Published: April 2022

Functional gastrointestinal disorders (FGIDs) are very common and life-impacting in children and young adults, covering 50% of pediatric gastroenterologist consultations. As it is known, FGIDs may be due to alterations in the gut–brain axis, dysbiosis and dysregulation of intestinal barrier, causing leaky gut. This may enhance increased antigen and bacterial passage through a damaged mucosa, worsening the impact of different medical conditions such as FGIDs. Little is known about the role of nutrients in modifying this “barrier disruption”. This narrative review aims to analyze the clinical evidence concerning diet and Intestinal Permeability (IP) in FGIDs in children. We searched the PubMed/Medline library for articles published between January 2000 and November 2021 including children aged 0–18 years old, using keywords related to the topic. Since diet induces changes in the intestinal barrier and microbiota, we aimed at clarifying how it is possible to modify IP in FGIDs by diet modulation, and how this can impact on gastrointestinal symptoms. We found that) is that small changes in eating habits, such as a low-FODMAP diet, an adequate intake of fiber and intestinal microbiota modulation by prebiotics and probiotics, seem to lead to big improvements in quality of life.
Analysis of the Relationship among Cognitive Impairment, Nutritional Indexes and the Clinical Course among COVID-19 Patients Discharged from Hospital—Preliminary Report
Authors: Klimkiewicz Jakub , Pankowski Daniel , Wytrychiewicz-Pankowska Kinga , Klimkiewicz Anna , Siwik Paulina , Klimczuk Joanna , Lubas Arkadiusz
Published: April 2022

Numerous data indicate the presence of cognitive impairment in people who have undergone COVID-19, often called COVID Fog (CF). This phenomenon persists even 6 months after infection, and its etiology and pathogenesis are not fully known. The aim of this article was to analyze the relationship among cognitive functioning, clinical data and nutrition indexes in patients discharged from the COVID-19 hospital of the Military Institute of Medicine, Warsaw, Poland. The sample comprised 17 individuals—10 women and 7 men, with ages of 65 ± 14 years. Cognitive impairment was measured with the use of the Montreal Cognitive Assessment (MoCA). The nutrition parameters included: hemoglobin, red blood cells, total cholesterol and its fractions, triglycerides, total protein, albumin, urea, creatinine, phosphates, calcium and sodium. The analysis showed that albumin concentration significantly correlated with the total MoCA score and especially with the short-term memory test score. Conversely, total cholesterol, and especially LDL concentrations, were highly and negatively associated with the MoCA score. In conclusion: markers of nutritional status are correlated with the severity of CF. Individuals with malnutrition or risk of malnutrition should be screened for CF. Further studies need to be performed in this area.