bluuebunny/crossref_metadata_2025 huggingface dataset:
Antarctic Marine Algae Extracts as a Potential Natural Resource to Protect Epithelial Barrier Integrity
Authors: Ko Seong-Hee , Lim YoonHee , Kim Eun Jae , Ko Young Wook , Hong In-Sun , Kim Sanghee , Jung YunJae
Published: September 2022

The intestine and skin provide crucial protection against the external environment. Strengthening the epithelial barrier function of these organs is critical for maintaining homeostasis against inflammatory stimuli. Recent studies suggest that polar marine algae are a promising bioactive resource because of their adaptation to extreme environments. To investigate the bioactive properties of polar marine algae on epithelial cells of the intestine and skin, we created extracts of the Antarctic macroalgae Himantothallus grandifolius, Plocamium cartilagineum, Phaeurus antarcticus, and Kallymenia antarctica, analyzed the compound profiles of the extracts using gas chromatography-mass spectrometry, and tested the protective activities of the extracts on human intestinal and keratinocyte cell lines by measuring cell viability and reactive oxygen species scavenging. In addition, we assessed immune responses modulated by the extracts by real-time polymerase chain reaction, and we monitored the barrier-protective activities of the extracts on intestinal and keratinocyte cell lines by measuring transepithelial electrical resistance and fluorescence-labeled dextran flux, respectively. We identified bioactive compounds, including several fatty acids and lipid compounds, in the extracts, and found that the extracts perform antioxidant activities that remove intracellular reactive oxygen species and scavenge specific radicals. Furthermore, the Antarctic marine algae extracts increased cell viability, protected cells against inflammatory stimulation, and increased the barrier integrity of cells damaged by lipopolysaccharide or ultraviolet radiation. These results suggest that Antarctic marine algae have optimized their composition for polar environments, and furthermore, that the bioactive properties of compounds produced by Antarctic marine algae can potentially be used to develop therapeutics to promote the protective barrier function of the intestine and skin.
Recyclability Definition of Recycled Nanofiltration Membranes through a Life Cycle Perspective and Carbon Footprint Indicator
Authors: Senán-Salinas Jorge , Landaburu-Aguirre Junkal , García-Pacheco Raquel , García-Calvo Eloy
Published: September 2022

The direct end-of-life recycling of reverse osmosis membranes (RO) into recycled nanofiltration (r-NF) membranes has been pointed out as a circular technology. For the first time, an environmental analysis of the whole life cycle of r-NF membranes was performed, focused on their usage. The carbon footprint (CF) of NF water treatment processes (Functional Unit: 1 m3 of treated water) with different pressure vessel (PV) designs and energy sources using r-NF and commercial NF-270-400 was quantified. Moreover, to compensate for the lower permeability of the r-NF, two design strategies were assessed: A) an increment in inlet pressure, and B) an increase in the number of modules. The inventory included energy modelling for each design and membrane. The interaction of both strategies with the permeability and service life of r-NF, together with different energy sources, was assessed using a novel hybrid analytical–numerical method. The relevance of energy use at the usage stage was highlighted. Therefore, r-NF permeability is the foremost relevant parameter for the definition of CF. The low impact of the r-NF replacement favoured strategy B. The use of an environmental indicator (CF) made it possible to identify the frontiers of the recyclability and applicability of r-NF membranes.
Synthesis and Characterization of Amino Acid Decyl Esters as Early Membranes for the Origins of Life
Authors: Lago Isabella , Black Lissa , Wilfinger Maximillian , Maurer Sarah E.
Published: September 2022

Understanding how membrane forming amphiphiles are synthesized and aggregate in prebiotic settings is required for understanding the origins of life on Earth 4 billion years ago. Amino acids decyl esters were prepared by dehydration of decanol and amino acid as a model for a plausible prebiotic reaction at two temperatures. Fifteen amino acids were tested with a range of side chain chemistries to understand the role of amino acid identity on synthesis and membrane formation. Products were analyzed using LC-MS as well as microscopy. All amino acids tested produced decyl esters, and some of the products formed membranes when rehydrated in ultrapure water. One of the most abundant prebiotic amino acids, alanine, was remarkably easy to get to generate abundant, uniform membranes, indicating that this could be a selection mechanism for both amino acids and their amphiphilic derivatives.
Low-Voltage Capacitor Electrical Discharge Consolidation of Iron Powder
Authors: Aranda Rosa María , Ternero Fátima , Aranda Beatriz , Montes Juan Manuel , Cuevas Francisco G.
Published: September 2022

Commercially pure iron powder has been processed by the capacitor electrical discharge consolidation technique. This consolidation technique applies an external pressure and, at the same time, heats a metallic powder mass by the Joule effect of a high-voltage and high-intensity electric current. In this work, a capacitor charged at low voltage has been used instead. The effect of the initial porosity of the Fe powder mass, i.e., of the precompaction pressure, and the number of discharges from the capacitor have been studied. The densification and remaining porosity, the sintering level, the Vickers microhardness, and the electrical resistivity of the sintered compacts have been studied. Compacts sintered by the conventional powder metallurgy route of cold pressing and furnace sintering were also prepared for comparison. Results show that a high initial porosity provides a high electrical resistance in the powder column, a necessary requisite for the Joule effect to increase densification with the number of discharges. Thus, the final porosity decreases to 0.22 after 50 discharges in the powder mass with an initial porosity of 0.30. With this initial porosity, the sintering process increases Vickers microhardness from 29 to 51 HV10 and decreases the electrical resistivity of the powder mass from 3.53 × 10−2 to 5.38 × 10−4 Ω·m. An initial porosity of 0.2 does not make the compacts densify, but a certain bond between particles is attained, increasing microhardness and decreasing electrical resistivity as the number of discharges increases. Lower initial porosities make the powder mass behave as an electrical conductor with no appreciable changes even after 50 electrical discharges.
Microstructural Development of Ti-6Al-4V Alloy via Powder Metallurgy and Laser Powder Bed Fusion
Authors: Dareh Baghi Alireza , Nafisi Shahrooz , Ebendorff-Heidepriem Heike , Ghomashchi Reza
Published: September 2022

A detailed study was carried out to gain a better understanding of the microstructural differences between Ti-6Al-4V parts fabricated via the conventional powder metallurgy (PM) and the laser powder bed fusion (L-PBF) 3D printing routes. The parts were compared in terms of the constituent phases in the microstructure and their effects on the micro- and nano-hardness. In L-PBF parts, the microstructure has a single phase of martensitic α′ with hcp crystal structure and acicular laths morphology, transformed from prior parent phase β formed upon solidification of the melt pool. However, for the sintered parts via powder metallurgy, two phases of α and β are noticeable and the microstructure is composed of α grains and α + β Lamellae. The microhardness of L-PBF processed Ti-6Al-4V samples is remarkably higher than that of the PM samples but, surprisingly, the nano-hardness of the bulk martensitic phase α′ (6.3 GPa) is almost the same as α (i.e., 6.2 GPa) in PM samples. This confirms the rapid cooling of the β phase does not have any effect on the hardening of the bulk martensitic hcp α′. The high microhardness of L-PBF parts is due to the fine lath morphology of α′, with a large concentration of low angle boundaries of α′. Furthermore, it is revealed that for the α phase in PM samples, a higher level of vanadium concentration lowers the nano-hardness of the α phase. In addition, as expected, the compacting pressure and sintering temperature during the PM process led to variations in the porosity level as well as the microstructural morphology of the fabricated specimens, which will in turn have a significant effect on the mechanical properties.
Metallic Glassy Hollow Microfibers
Authors: Zhao Jing , Yi Jun , Huang Bo , Wang Gang
Published: September 2022

Hollow microfibers can be fabricated by using different materials such as metals and glass. The inner diameter of strong, tough, and conductive metallic tubes is on a submillimeter scale while that of quartz glass tubes made by thermoplastic forming can reach 5 nm. However, quartz glass tubes are brittle and nonconductive. Metallic glasses (MGs) are strong, tough, conductive, and have a thermoplastic forming ability. Theoretically, such materials can be used to produce strong, tough, and conductive hollow microfibers. Here, we report a method to fabricate MG hollow microfibers via thermoplastic forming bulk Pd43Cu27Ni10P20 MG tubes in their supercooled-liquid region. Uniform and smooth MG hollow microfibers with single and multiple channels were successfully fabricated by this method. Investigation of the heterogeneous microstructure of the fibers revealed their forming mechanism. The hollow microfibers might attract scientific interest and may have engineering applications in areas such as electrochemistry, microelectromechanical devices, medicine, and biology.
A Stability Training Method of Legged Robots Based on Training Platforms and Reinforcement Learning with Its Simulation and Experiment
Authors: Wu Weiguo , Gao Liyang , Zhang Xiao
Published: September 2022

This paper continues the proposed idea of stability training for legged robots with any number of legs and any size on a motion platform and introduces the concept of a learning-based controller, the global self-stabilizer, to obtain a self-stabilization capability in robots. The overall structure of the global self-stabilizer is divided into three modules: action selection, adjustment calculation and joint motion mapping, with corresponding learning algorithms proposed for each module. Taking the human-sized biped robot, GoRoBoT-II, as an example, simulations and experiments in three kinds of motions were performed to validate the feasibility of the proposed idea. A well-designed training platform was used to perform composite random amplitude-limited disturbances, such as the sagittal and lateral tilt perturbations (±25°) and impact perturbations (0.47 times the robot gravity). The results show that the proposed global self-stabilizer converges after training and can dynamically combine actions according to the system state. Compared with the controllers used to generate the training data, the trained global self-stabilizer increases the success rate of stability verification simulations and experiments by more than 20% and 15%, respectively.
Prediction of Prospecting Target Based on Selective Transfer Network
Authors: Huang Yongjie , Feng Quan , Zhang Wanting , Zhang Li , Gao Le
Published: September 2022

In recent years, with the integration and development of artificial intelligence technology and geology, traditional geological prospecting has begun to change to intelligent prospecting. Intelligent prospecting mainly uses machine learning technology to predict the prospecting target area by mining the correlation between geological variables and metallogenic characteristics, which usually requires a large amount of data for training. However, there are some problems in the actual research, such as fewer geological sample data and irregular mining features, which affect the accuracy and reliability of intelligent prospecting prediction. Taking the Pangxidong study area in Guangdong Province as an example, this paper proposes a deep learning framework (SKT) for prospecting target prediction based on selective knowledge transfer and carries out intelligent prospecting target prediction research based on geochemical data in Pangxidong. The irregular features of different scales in the mining area are captured by dilation convolution, and the weight parameters of the source network are selectively transferred to different target networks for training, so as to increase the generalization performance of the model. A large number of experimental results show that this method has obvious advantages over other state-of-the-art methods in the prediction of prospecting target areas, and the prediction effect in the samples with mines is greatly improved, which can effectively alleviate the problems of a small number of geological samples and irregular features of mining areas in prospecting prediction.
Geochemical and Sr-Isotopic Study of Clinopyroxenes from Somma-Vesuvius Lavas: Inferences for Magmatic Processes and Eruptive Behavior
Authors: Di Renzo Valeria , Pelullo Carlo , Arienzo Ilenia , Civetta Lucia , Petrosino Paola , D’Antonio Massimo
Published: September 2022

Somma-Vesuvius is one of the most dangerous active Italian volcanoes, due to the explosive character of its activity and because it is surrounded by an intensely urbanized area. For mitigating the volcanic risks, it is important to define how the Somma-Vesuvius magmatic system worked during the past activity and what processes took place. A continuous coring borehole drilled at Camaldoli della Torre, along the southern slopes of Somma-Vesuvius, allowed reconstructing its volcanic and magmatic history in a previous study. In this work, the wide range of chemical (Mg# = 92–69) and isotopic (87Sr/86Sr = 0.70781–0.70681) compositions, collected on single clinopyroxene crystals separated from selected lava flow units of the Camaldoli della Torre sequence, have been integrated with the already available bulk geochemical and Sr-isotopic data. The detected chemical and isotopic signatures and their variation through time allow us to better constrain the behavior of the volcano magmatic feeding system, highlighting that mixing and/or assimilation processes occurred before a significant change in the eruptive dynamics at Somma-Vesuvius during a period of polycyclic caldera formation, starting with the Pomici di Base Plinian eruption (ca. 22 ka).
(20S) Ginsenoside Rh2-Activated, Distinct Apoptosis Pathways in Highly and Poorly Differentiated Human Esophageal Cancer Cells
Authors: Li He , Han Chunxiao , Chen Chen , Han Guanghong , Li Yang
Published: September 2022

Ginsenoside Rh2 (G-Rh2), a rare ginsenoside isolated from red ginseng, has considerable anti-cancer activity and induces apoptosis in a variety of cancer cells, but its activity in esophageal cancer cells is unclear. In this study, we examined the cytotoxic activity of (20S) G-Rh2 in highly differentiated esophageal squamous ECA109 cells and poorly differentiated esophageal squamous TE-13 cells. (20S) G-Rh2 exerted intense cytotoxicity in ECA109 and TE-13 cells with an IC50 of 2.9 and 3.7 μg/mL, respectively. After treatment with G-Rh2, Bcl-2, and Bcl-xL, the two main anti-apoptosis Bcl-2 family proteins upregulated, and Bax and Bak, the two key pro-apoptosis proteins translocated to mitochondria in both cell lines. At the same time, cytochrome c and Smac released from mitochondria, followed by caspase-9 activation, indicating that a mitochondria-mediated intrinsic apoptosis pathway was activated in both cell lines upon treatment with (20S) G-Rh2. It is noteworthy that (20S) G-Rh2 upregulated the transcription and protein expression of two death receptors, Fas and DR5, and subsequently activated Caspase-8 in the TE-13 cells but not in the ECA109 cells. Taken together, we demonstrated the potent anti-esophageal cancer cell activity of (20S) G-Rh2 and showed its working mechanism in two differentiated esophageal cancer cells, which can provide important evidence for developing an effective strategy for anti-esophageal cancer treatment.
Lipid Nanoparticles for mRNA Delivery to Enhance Cancer Immunotherapy
Authors: Wang Hong-Li , Wang Zhi-Gang , Liu Shu-Lin
Published: September 2022

Messenger RNA (mRNA) is being developed by researchers as a novel drug for the treatment or prevention of many diseases. However, to enable mRNA to fully exploit its effects in vivo, researchers need to develop safer and more effective mRNA delivery systems that improve mRNA stability and enhance the ability of cells to take up and release mRNA. To date, lipid nanoparticles are promising nanodrug carriers for tumor therapy, which can significantly improve the immunotherapeutic effects of conventional drugs by modulating mRNA delivery, and have attracted widespread interest in the biomedical field. This review focuses on the delivery of mRNA by lipid nanoparticles for cancer treatment. We summarize some common tumor immunotherapy and mRNA delivery strategies, describe the clinical advantages of lipid nanoparticles for mRNA delivery, and provide an outlook on the current challenges and future developments of this technology.
Comparison of LC-MS3 and LC-MRM Method for Quantifying Voriconazole and Its Application in Therapeutic Drug Monitoring of Human Plasma
Authors: Ren Wenbo , Yin Lei , Zhang Gaixia , Zhai Taiyu , Huang Jing
Published: September 2022

The TDM of voriconazole which exhibits wide inter-individual variability is indispensable for treatment in clinic. In this study, a method that high-performance liquid chromatography tandem mass spectrometry cubed (HPLC-MS3) is first built and validated to quantify voriconazole in human plasma. The system is composed of Shimadzu Exion LCTM UPLC coupled with a Qtrap 5500 mass spectrometer. The separation of voriconazole is performed on a Poroshell 120 SB-C18 column at a flow rate of 0.8 mL/min remaining 7 min for each sample. The calibration curves are linear in the concentration range of 0.25–20 μg/mL. Intra-day and inter-day accuracies and precisions are within 8.0% at three concentrations, and the recoveries and matrix effect are all within accepted limits. In terms of stability, there is no significant degradation of voriconazole under various conditions. The HPLC-MS3 and HPLC-MRM (multiple reaction monitoring) methods are compared in 42 patients with Passing–Bablok regression and Bland–Altman plots, and the results show no significant difference between the two methods. However, HPLC-MS3 has a higher S/N (signal-to-noise ratio) and response than the MRM. Finally, the HPLC-MS3 assay is successfully applied to monitor the TDM (therapeutic drug monitoring) of voriconazole in human plasma, and this verifies that the dosing guidelines for voriconazole have been well implemented in the clinic and patients have received excellent treatment.
5-Amino-3-methyl-Isoxazole-4-carboxylic Acid as a Novel Unnatural Amino Acid in the Solid Phase Synthesis of α/β-Mixed Peptides
Authors: Bąchor Urszula , Lizak Agnieszka , Bąchor Remigiusz , Mączyński Marcin
Published: September 2022

The hybrid peptides consisting of α and β-amino acids show great promise as peptidomimetics that can be used as therapeutic agents. Therefore, the development of new unnatural amino acids and the methods of their incorporation into the peptide chain is an important task. Here, we described our investigation of the possibility of 5-amino-3-methyl-isoxazole-4-carboxylic acid (AMIA) application in the solid phase peptide synthesis. This new unnatural β-amino acid, presenting various biological activities, was successfully coupled to a resin-bound peptide using different reaction conditions, including classical and ultrasonic agitated solid-phase synthesis. All the synthesized compounds were characterized by tandem mass spectrometry. The obtained results present the possibility of the application of this β-amino acid in the synthesis of a new class of bioactive peptides.
A Combined Experimental and Computational Study on the Adsorption Sites of Zinc-Based MOFs for Efficient Ammonia Capture
Authors: Zhang Dongli , Shen Yujun , Ding Jingtao , Zhou Haibin , Zhang Yuehong , Feng Qikun , Zhang Xi , Chen Kun , Xu Pengxiang , Zhang Pengyue
Published: September 2022

Ammonia (NH3) is a common pollutant mostly derived from pig manure composting under humid conditions, and it is absolutely necessary to develop materials for ammonia removal with high stability and efficiency. To this end, metal–organic frameworks (MOFs) have received special attention because of their high selectivity of harmful gases in the air, resulting from their large surface area and high density of active sites, which can be tailored by appropriate modifications. Herein, two synthetic metal–organic frameworks (MOFs), 2-methylimidazole zinc salt (ZIF-8) and zinc-trimesic acid (ZnBTC), were selected for ammonia removal under humid conditions during composting. The two MOFs, with different organic linkers, exhibit fairly distinctive ammonia absorption behaviors under the same conditions. For the ZnBTC framework, the ammonia intake is 11.37 mmol/g at 298 K, nine times higher than that of the ZIF-8 framework (1.26 mmol/g). In combination with theoretical calculations, powder XRD patterns, FTIR, and BET surface area tests were conducted to reveal the absorption mechanisms of ammonia for the two materials. The adsorption of ammonia on the ZnBTC framework can be attributed to both physical and chemical adsorption. A strong coordination interaction exists between the nitrogen atom from the ammonia molecule and the zinc atom in the ZnBTC framework. In contrast, the absorption of ammonia in the ZIF-8 framework is mainly physical. The weak interaction between the ammonia molecule and the ZIF-8 framework mainly results from the inherent severely steric hindrance, which is related to the coordination mode of the imidazole ligands and the zinc atom of this framework. Therefore, this study provides a method for designing promising MOFs with appropriate organic linkers for the selective capture of ammonia during manure composting.
Deciphering the Potential of Pre and Pro-Vitamin D of Mushrooms against Mpro and PLpro Proteases of COVID-19: An In Silico Approach
Authors: Tiwari Abhay , Singh Garima , Choudhir Gourav , Motiwale Mohit , Joshi Nidhi , Sharma Vasudha , Srivastava Rupesh K. , Sharma Satyawati , Tutone Marco , Singour Pradeep Kumar
Published: September 2022

Vitamin D’s role in combating the SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2), the virus causing COVID-19, has been established in unveiling viable inhibitors of COVID-19. The current study investigated the role of pre and pro-vitamin D bioactives from edible mushrooms against Mpro and PLpro proteases of SARS-CoV-2 by computational experiments. The bioactives of mushrooms, specifically ergosterol (provitamin D2), 7-dehydrocholesterol (provitamin-D3), 22,23-dihydroergocalciferol (provitamin-D4), cholecalciferol (vitamin-D3), and ergocalciferol (vitamin D2) were screened against Mpro and PLpro. Molecular docking analyses of the generated bioactive protease complexes unravelled the differential docking energies, which ranged from −7.5 kcal/mol to −4.5 kcal/mol. Ergosterol exhibited the lowest binding energy (−7.5 kcal/mol) against Mpro and PLpro (−5.9 kcal/mol). The Molecular Mechanics Poisson–Boltzmann Surface Area (MMPBSA) and MD simulation analyses indicated that the generated complexes were stable, thus affirming the putative binding of the bioactives to viral proteases. Considering the pivotal role of vitamin D bioactives, their direct interactions against SARS-CoV-2 proteases highlight the promising role of bioactives present in mushrooms as potent nutraceuticals against COVID-19.
Chemical Synthesis and Biological Activities of Amaryllidaceae Alkaloid Norbelladine Derivatives and Precursors
Authors: Girard Marie-Pierre , Karimzadegan Vahid , Héneault Marianne , Cloutier Francis , Bérubé Gervais , Berthoux Lionel , Mérindol Natacha , Desgagné-Penix Isabel
Published: September 2022

Amaryllidaceae alkaloids (AAs) are a structurally diverse family of alkaloids recognized for their many therapeutic properties, such as antiviral, anti-cholinesterase, and anticancer properties. Norbelladine and its derivatives, whose biological properties are poorly studied, are key intermediates required for the biosynthesis of all ~650 reported AAs. To gain insight into their therapeutic potential, we synthesized a series of O-methylated norbelladine-type alkaloids and evaluated their cytotoxic effects on two types of cancer cell lines, their antiviral effects against the dengue virus (DENV) and the human immunodeficiency virus 1 (HIV-1), and their anti-Alzheimer’s disease (anti-cholinesterase and -prolyl oligopeptidase) properties. In monocytic leukemia cells, norcraugsodine was highly cytotoxic (CC50 = 27.0 μM), while norbelladine was the most cytotoxic to hepatocarcinoma cells (CC50 = 72.6 μM). HIV-1 infection was impaired only at cytotoxic concentrations of the compounds. The 3,4-dihydroxybenzaldehyde (selectivity index (SI) = 7.2), 3′,4′-O-dimethylnorbelladine (SI = 4.8), 4′-O-methylnorbelladine (SI > 4.9), 3′-O-methylnorbelladine (SI > 4.5), and norcraugsodine (SI = 3.2) reduced the number of DENV-infected cells with EC50 values ranging from 24.1 to 44.9 μM. The O-methylation of norcraugsodine abolished its anti-DENV potential. Norbelladine and its O-methylated forms also displayed butyrylcholinesterase-inhibition properties (IC50 values ranging from 26.1 to 91.6 μM). Altogether, the results provided hints of the structure–activity relationship of norbelladine-type alkaloids, which is important knowledge for the development of new inhibitors of DENV and butyrylcholinesterase.
Synthesis of [B,Al]-EWT-Type Zeolite and Its Catalytic Properties
Authors: Wang Youju , Bai Yongyue , Chen Pohua , Chen Qiang , Wang Yongrui , Shu Xingtian
Published: September 2022

EWT zeolite belongs to ultra-large pore zeolite with the 10MR and 21MR channels, which has good thermal stability, certain acid strength and good application prospects in petroleum refining and petrochemical reactions. However, EWT zeolite has fewer medium/strong acid sites, especially Brönsted acid sites, which makes it difficult to apply to acid-catalyzed reactions. The regulation of acid amount and distribution was achieved by boron and aluminum substitution into the siliceous framework of EWT. The physico-chemical properties of the samples were characterized by XRD, SEM, N2 adsorption-desorption, XRF, ICP, Py-IR, NH3-TPD and 11B & 27Al & 29Si MAS NMR. The results show that quantities of boron and aluminum elements can occupy the framework of [B,Al]-EWT to increase the density of medium and strong acid centers, with more acidity and Brönsted acid centers than EWT zeolite. In the reaction of glycerol with cyclohexanone, the conversion of the sample (U-90-08-10/U-90-H-HCl) is significantly higher than that of the EWT sample, approaching or exceeding the Beta zeolite. A catalytic activity study revealed a direct correlation between the Brönsted acidic site concentration and the activity of the catalyst. The U-90-08-10-H catalyst was also considerably stable in the catalytic process. This work shows, for the first time, that extra-large pore zeolites can be used in industrial acid-catalytic conversion processes with excellent catalytic performance.
Effects of Extraction Technique on the Content and Antioxidant Activity of Flavonoids from Gossypium Hirsutum linn. Flowers
Authors: Dong Jiaxing , Zhou Kehai , Ge Xiaoyang , Xu Na , Wang Xiao , He Qing , Zhang Chenxu , Chu Jun , Li Qinglin
Published: September 2022

Cotton is one of the Uyghur medical materials in China and is rich in flavonoids. Flavonoids have important pharmacological effects. The yield of flavonoids in traditional extraction methods is low, which affects the development of flavonoids. Therefore, it is urgent to optimize the extraction techniques. The yield of flavonoids in cotton flowers was effectively improved by response surface methodology, and the highest yield of flavonoids reached 5.66%, and the optimal extraction process conditions were obtained. The DPPH free radical scavenging rate, hydroxyl free radical scavenging rate, superoxide anion free radical scavenging rate, and reducing ability were tested to reflect the antioxidant capacity of flavonoids. The flavonoids had an excellent antioxidant effect. Cell experiments suggested that the flavonoids had the effect of protecting glutamate-induced damage to HT-22 cells. The results of this study provide a theoretical basis for the extraction of cotton flowers flavonoids and the comprehensive evaluation of antioxidant products, as well as the extraction of other plant flavonoids.
Assessing the Functional and Structural Stability of the Met80Ala Mutant of Cytochrome c in Dimethylsulfoxide
Authors: Di Rocco Giulia , Ranieri Antonio , Borsari Marco , Sola Marco , Bortolotti Carlo Augusto , Battistuzzi Gianantonio
Published: September 2022

The Met80Ala variant of yeast cytochrome c is known to possess electrocatalytic properties that are absent in the wild type form and that make it a promising candidate for biocatalysis and biosensing. The versatility of an enzyme is enhanced by the stability in mixed aqueous/organic solvents that would allow poorly water-soluble substrates to be targeted. In this work, we have evaluated the effect of dimethylsulfoxide (DMSO) on the functionality of the Met80Ala cytochrome c mutant, by investigating the thermodynamics and kinetics of electron transfer in mixed water/DMSO solutions up to 50% DMSO v/v. In parallel, we have monitored spectroscopically the retention of the main structural features in the same medium, focusing on both the overall protein structure and the heme center. We found that the organic solvent exerts only minor effects on the redox and structural properties of the mutant mostly as a result of the modification of the dielectric constant of the solvent. This would warrant proper functionality of this variant also under these potentially hostile experimental conditions, that differ from the physiological milieu of cytochrome c.
Experimental Investigation of Rheological Properties and Thermal Conductivity of SiO2–TiO2 Composite Nanofluids Prepared by Atomic Layer Deposition
Authors: Várady Zalán István , Ba Thong Le , Parditka Bence , Erdélyi Zoltán , Hernadi Klara , Karacs Gábor , Gróf Gyula , Szilágyi Imre Miklós
Published: September 2022

In the current research, surface-modified SiO2 nanoparticles were used upon immersion in an applied base fluid (ethylene glycol:water = 1:1). The atomic layer deposition method (ALD) was introduced to obtain a thin layer of TiO2 to cover the surface of SiO2 particles. After the ALD modification, the TiO2 content was monitored by energy dispersive X-ray spectroscopy (EDS). Transmission electron microscopy (TEM) and FT-IR spectroscopy were applied for the particle characterization. The nanofluids contained 0.5, 1.0, and 1.5 volume% solid particles and zeta potential measurements were examined in terms of colloid stability. A rotation viscosimeter and thermal conductivity analyzer were used to study the nanofluids’ rheological properties and thermal conductivity. These two parameters were investigated in the temperature range of 20 °C and 60 °C. Based on the results, the thin TiO2 coating significant impacted these parameters.
Effect of Oleylamine on the Surface Chemistry, Morphology, Electronic Structure, and Magnetic Properties of Cobalt Ferrite Nanoparticles
Authors: Ansari Sumayya M. , Sinha Bhavesh B. , Sen Debasis , Sastry Pulya U. , Kolekar Yesh D. , Ramana C. V.
Published: September 2022

The influence of oleylamine (OLA) concentration on the crystallography, morphology, surface chemistry, chemical bonding, and magnetic properties of solvothermal synthesized CoFe2O4 (CFO) nanoparticles (NPs) has been thoroughly investigated. Varying OLA concentration (0.01–0.1 M) resulted in the formation of cubic spinel-structured CoFe2O4 NPs in the size-range of 20–14 (±1) nm. The Fourier transform spectroscopic analyses performed confirmed the OLA binding to the CFO NPs. The thermogravimetric measurements revealed monolayer and multilayer coating of OLA on CFO NPs, which were further supported by the small-angle X-ray scattering measurements. The magnetic measurements indicated that the maximum saturation (MS) and remanent (Mr) magnetization decreased with increasing OLA concentration. The ratio of maximum dipolar field (Hdip), coercivity (HC), and exchanged bias field (Hex) (at 10 K) to the average crystallite size (Dxrd), i.e., (Hdip/Dxrd), (HC/Dxrd), and (Hex/Dxrd), increased linearly with OLA concentration, indicating that OLA concurrently controls the particle size and interparticle interaction among the CFO NPs. The results and analyses demonstrate that the OLA-mediated synthesis allowed for modification of the structural and magnetic properties of CFO NPs, which could readily find potential application in electronics and biomedicine.
Europium (II)-Doped CaF2 Nanocrystals in Sol-Gel Derived Glass-Ceramic: Luminescence and EPR Spectroscopy Investigations
Authors: Secu Corina , Rostas Arpad-Mihai , Secu Mihail
Published: September 2022

The remarkable properties of Eu2+-activated phosphors, related to the broad and intense luminescence of Eu2+ ions, showed a high potential for a wide range of optical-related applications. Oxy-fluoride glass-ceramic containing Europium (II)-doped CaF2 nanocrystals embedded in silica matrix were produced in two steps: glass-ceramization in air at 800° with Eu3+-doped CaF2 nanocrystals embedded followed by Eu3+ to Eu2+ reduction during annealing in reducing atmosphere. The broad, blue luminescence band at 425 nm and with the long, weak tail in the visible range is assigned to the d → f type transition of the Eu2+ located inside the CaF2 nanocrystals in substitutional and perturbed sites, respectively; the photoluminescence quantum yield was about 0.76. The X-ray photoelectron spectroscopy and Electron paramagnetic spectroscopy confirmed the presence of Eu2+ inside the CaF2 nanocrystals. Thermoluminescence curves recorded after X-ray irradiation of un-doped and Eu2+-doped glass-ceramics showed a single dominant glow peak at 85 °C related to the recombination between F centers and Eu2+ related hole within the CaF2 nanocrystals. The applicability of the procedure can be tested to obtain an oxy-fluoride glass-ceramic doped with other divalent ions such as Sm2+, Yb2+, as nanophosphors for radiation detector or photonics-related applications.
Combined Effect of NZVI and H2O2 on the Cyanobacterium Microcystis aeruginosa: Performance and Mechanism
Authors: Kong Yun , Ji Lipeng , Wang Yue , Li Jiake , Lu Hao , Mo Shuhong , Wang Xianxun , Zhu Liang , Xu Xiangyang , Zheng Xing
Published: September 2022

In order to eliminate the harmful cyanobacterium Microcystis aeruginosa and the algal organic matters (AOMs) produced by M. aeruginosa, the combined process of nanoscale zero-valent iron (NZVI) and hydrogen peroxide (H2O2) has been carried out, and the removal mechanism has also been clarified. As the initial cyanobacterial cell concentration is 1.0 (±0.05) × 105 cells·mL−1, all the treatments of NZVI, H2O2, and NZVI/H2O2 have inhibition effects on both the Chl a contents and photosynthetic pigments, with the Chl a removal efficiency of 47.3%, 80.5%, and 90.7% on the 5th day, respectively; moreover, the variation of ζ potential is proportional to that of the Chl a removal efficiency. The malondialdehyde content and superoxide dismutase activity are firstly increased and ultimately decreased to mitigate the oxidative stress under all the treatments. Compared with NZVI treatment alone, the oxidation of the H2O2 and NZVI/H2O2 processes can effectively destroy the antioxidant enzyme system and then inactivate the cyanobacterial cells, which further leads to the release of photosynthetic pigments and intracellular organic matters (IOM); in addition, the IOM removal efficiency (in terms of TOC) is 61.3% and 54.1% for the H2O2 and NZVI/H2O2 processes, respectively. Although NZVI is much more effective for extracellular organic matters (EOM) removal, it is less effective for IOM removal. The results of the three-dimensional EEM fluorescence spectra analysis further confirm that both H2O2 and NZVI/H2O2 have the ability to remove fluorescent substances from EOM and IOM, due to the oxidation mechanism; while NZVI has no removal effect for the fluorescent substances from EOM, it can remove part of fluorescent substances from IOM due to the agglomeration. All the results demonstrate that the NZVI/H2O2 process is a highly effective and applicable technology for the removal of M. aeruginosa and AOMs.
Iron-Based Hollow Nanoplatforms for Cancer Imaging and Theranostics
Authors: Luo Shun , Qin Shuijie , Oudeng Gerile , Zhang Li
Published: September 2022

Over the past decade, iron (Fe)-based hollow nanoplatforms (Fe-HNPs) have attracted increasing attention for cancer theranostics, due to their high safety and superior diagnostic/therapeutic features. Specifically, Fe-involved components can serve as magnetic resonance imaging (MRI) contrast agents (CAs) and Fenton-like/photothermal/magnetic hyperthermia (MTH) therapy agents, while the cavities are able to load various small molecules (e.g., fluorescent dyes, chemotherapeutic drugs, photosensitizers, etc.) to allow multifunctional all-in-one theranostics. In this review, the recent advances of Fe-HNPs for cancer imaging and treatment are summarized. Firstly, the use of Fe-HNPs in single T1-weighted MRI and T2-weighted MRI, T1-/T2-weighted dual-modal MRI as well as other dual-modal imaging modalities are presented. Secondly, diverse Fe-HNPs, including hollow iron oxide (IO) nanoparticles (NPs), hollow matrix-supported IO NPs, hollow Fe-complex NPs and hollow Prussian blue (PB) NPs are described for MRI-guided therapies. Lastly, the potential clinical obstacles and implications for future research of these hollow Fe-based nanotheranostics are discussed.
Amphiphilic Cationic Peptide-Coated PHA Nanosphere as an Efficient Vector for Multiple-Drug Delivery
Authors: Zhang Fanghua , Zhang Chao , Fu Shuangqing , Liu Huandi , Han Mengnan , Fan Xueyu , Zhang Honglei , Li Wei
Published: September 2022

Amphiphilic core–shell (ACS) nanoparticles are gaining increasing research interest for multi-drug delivery in cancer therapy. In this work, a new cationic peptide-coated PHA nanosphere was prepared by self-assembly of a hydrophobic core of biodegradable poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) and a hydrophilic shell of fusion proteins of PHA granule-associated protein (PhaP) and cationic peptide RALA through a strong hydrophobic effect. The hydrophobic drug curcumin (Cur) was encapsulated in PHBHHx nanoparticles. The chemotherapy drug 5-fluorouracil (5-FU) was administered in the form of its metabolite oligomeric 5-fluorodeoxyuridine (FUdR). Fifteen consecutive FUdR (FUdR15S) were adsorbed on the surface of PHBHHx nanoparticles by electrostatic interaction with RALA to form Cur@PHBX-PR/FUdR15S. Such amphiphilic cationic nanospheres had 88.3% EE of Cur and the drug loading of Cur and FUdR were 7.8% and 12.1%. The dual-drug-loaded nanospheres showed a time-differential release of Cur and FUdR. In addition, Cur@PHBX-PR/FUdR15S exhibited excellent anticancer activity and played a vital role in promoting the synergistic effect of FUdR and Cur in gastric cancer cells. The exploration of antitumor mechanisms demonstrated that Cur improved the activity of apoptosis-related proteins and cancer cells sensitized to FUdR. This amphiphilic core–shell system can serve as a general platform for sequential delivery of multiple drugs to treat several cancer cells.
Adsorption of Mercury on Oxidized Graphenes
Authors: Tene Talia , Bellucci Stefano , Guevara Marco , Arias Arias Fabian , Sáez Paguay Miguel Ángel , Quispillo Moyota John Marcos , Arias Polanco Melvin , Scarcello Andrea , Vacacela Gomez Cristian , Straface Salvatore , Caputi Lorenzo S. , Torres F. Javier
Published: September 2022

Graphene oxide (GO) and its reduced form, reduced graphene oxide (rGO), are among the most predominant graphene derivatives because their unique properties make them efficient adsorbent nanomaterials for water treatment. Although extra-functionalized GO and rGO are customarily employed for the removal of pollutants from aqueous solutions, the adsorption of heavy metals on non-extra-functionalized oxidized graphenes has not been thoroughly studied. Herein, the adsorption of mercury(II) (Hg(II)) on eco-friendly-prepared oxidized graphenes is reported. The work covers the preparation of GO and rGO as well as their characterization. In a further stage, the description of the adsorption mechanism is developed in terms of the kinetics, the associated isotherms, and the thermodynamics of the process. The interaction between Hg(II) and different positions of the oxidized graphene surface is explored by DFT calculations. The study outcomes particularly demonstrate that pristine rGO has better adsorbent properties compared to pristine GO and even other extra-functionalized ones.
Investigation of the Surface Coating, Humidity Degradation, and Recovery of Perovskite Film Phase for Solar-Cell Applications
Authors: Bouich Amal , Marí-Guaita Julia , Baig Faisal , Hameed Khattak Yousaf , Soucase Bernabé Marí , Palacios Pablo
Published: September 2022

Presently, we inquire about the organic/inorganic cation effect on different properties based on structure, morphology, and steadiness in preparing a one-step solution of APbI3 thin films, where A = MA, FA, Cs, using spin coating. This study was conducted to understand those properties well by incorporating device modeling using SCAPS-1D software and to upgrade their chemical composition. X-ray diffraction (XRD) was used to analyze the crystal structures. Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) were conducted to characterize the surface morphology; photoluminescence, Transmission Electron Microscopy (TEM), and a UV–Visible spectrometer helped us to study the optical properties. The (110) plane is where we found the perovskite’s crystalline structure. According to the XRD results and by changing the type of cation, we influence stabilization and the growth of the APbI3 absorber layer. Hither, a homogenous, smooth-surfaced, pinhole-free perovskite film and large grain size are results from the cesium cation. For the different cations, the band gap’s range, revealed by the optical analysis, is from 1.4 to 1.8 eV. Moreover, the stability of CsPbI3 remains excellent for two weeks and in a ~60% humid environment. Based on the UV–Visible spectrometer and photoluminescence characterization, a numerical analysis for fabricated samples was also performed for stability analysis by modeling standard solar-cell structures HTL/APbI3/ETL. Modeling findings are in good agreement with experimental results that CsPbI3 is more stable, showing a loss % in PCE of 14.28%, which is smaller in comparison to FAPbI3 (44.46%) and MAPbI3 (20.24%).
Simulation of Figures of Merit for Barristor Based on Graphene/Insulator Junction
Authors: Lee Jun-Ho , Choi Inchul , Jeong Nae Bong , Kim Minjeong , Yu Jaeho , Jhang Sung Ho , Chung Hyun-Jong
Published: September 2022

We investigated the tunneling of graphene/insulator/metal heterojunctions by revising the Tsu–Esaki model of Fowler–Nordheim tunneling and direct tunneling current. Notably, the revised equations for both tunneling currents are proportional to V3, which originates from the linear dispersion of graphene. We developed a simulation tool by adopting revised tunneling equations using MATLAB. Thereafter, we optimized the device performance of the field-emission barristor by engineering the barrier height and thickness to improve the delay time, cut-off frequency, and power-delay product.
Towards the Configuration of a Photoelectrocatalytic Reactor: Part 2—Selecting Photoreactor Flow Configuration and Operating Variables by a Numerical Approach
Authors: Borrás-Jiménez Daniel , Silva-López Wilber , Nieto-Londoño César
Published: September 2022

This work aims to select a photoreactor flow configuration and operational conditions that maximize the Photocatalytic Space-time Yield in a photoelectrocatalytic reactor to degrade Reactive Red 239 textile dye. A numerical study by Computational Fluid Dynamics (CFD) was carried out to model the phenomena of momentum and species transport and surface reaction kinetics. The photoreactor flow configuration was selected between axial (AF) and tangential (TF) inlet and outlet flow, and it was found that the TF configuration generated a higher Space-time Yield (STY) than the AF geometry in both laminar and turbulent regimes due to the formation of a helical movement of the fluid, which generates velocity in the circumferential and axial directions. In contrast, the AF geometry generates a purely axial flow. In addition, to maximize the Photocatalytic Space-time Yield (PSTY), it is necessary to use solar radiation as an external radiation source when the flow is turbulent. In conclusion, the PSTY can be maximized up to a value of 45 g/day-kW at an inlet velocity of 0.2 m/s (inlet Reynolds of 2830), solar radiation for external illumination, and internal illumination by UV-LEDs of 14 W/m2, using a photoreactor based on tangent inlet and outlet flow.
Device Modelling and Optimization of Nanomaterial-Based Planar Heterojunction Solar Cell (by Varying the Device Dimensions and Material Parameters)
Authors: Moorthy Vijai Meyyappan , Srivastava Viranjay M.
Published: September 2022

The objective of this work is to model a multi-disciplinary (multi-physics) organic photovoltaic (OPV) using mathematical modeling and analyzing the behavior of a standard planar heterojunction (PHJ) or bi-layer thin-film photovoltaic device, supporting the optimization of an efficient device for future production and assisting in evaluating and choosing the materials required for the efficient device. In order to increase photodiode performance, the device structure and geometrical properties have also been optimized and evaluated. In this work, the effects of varying the device size and transport parameters on the performance parameters of a PHJ OPV structure comprised of Indium Tin Oxide as the anode (ITO), semiconducting single-wall carbon nanotube (s-SWCNT) as the donor, fullerene C70 as the acceptor, and Aluminium (Al) as the cathode have been analyzed. The conclusion suggests that a highly effective ITO/s-SWCNT/C70/Al PHJ solar cell may be fabricated if the suggested device is appropriately built with a thin layer and a high exciton diffusion length, bi-molecular recombination coefficient, and improved mobility charge carriers, in particular hole mobility in the cell’s donor layer. In addition, the displayed current–voltage (I–V) characteristics of the proposed PHJ device are clearly indicated, with the ITO/s-SWCNT/C70/Al combination having the greatest short-circuit current density (Jsc) value of 5.61 mA/cm2, open-circuit voltage (Voc) of 0.7 V, fill factor (FF) of 79% and efficiency (ɳ) of 3.1%. Results show that the electrical performance of organic solar cells is sensitive to the thickness of the photoactive substance. These results open the path for developing inexpensive and highly efficient solar cells.