bluuebunny/crossref_metadata_2025 huggingface dataset:
Multivariable Decoupling and Nonlinear Correction Method for Image-Based Closed-Loop Tracking of the Risley Prisms System
Authors: Xia Huayang , Li Jinying , Xia Yunxia , Yuan Liangzhu , Zhang Wenxue , Ma Haotong , Wen Piao
Published: November 2022

Image-based closed-loop tracking (IBCLT) is an important part of the process of target tracking. The Risley prism system has a unique advantage in improving the target tracking ability because of its compact and lightweight structure. Compared with traditional target tracking equipment, the Risley prism system has two difficulties in the process of IBCLT. First, the Risley prism is a complex coupling system of double input and double output. Second, the Risley prism itself is a nonlinear system. These problems lead to decrease in dynamic response and inconsistent target tracking capabilities. Thus, this paper proposes a method to implement multivariable decoupling and reduce the nonlinear effect. First, the boresight error of IBCLT is decoupled to the azimuth and elevation directions by the rotation matrix error-decoupling (RMED) method. Second, the gains of IBCLT in azimuth and elevation directions are independent variables that comes from two functions of the target elevation angle. The experimental results show that the IBCLT error deviation of different static targets in the field of view is within 0.025 arcsec, which is 70% lower compared with the fixed gain method. Furthermore, the steady-state error deviation of moving targets is controlled within 2.5 arcsec. These experimental results prove the feasibility and effectiveness of the proposed method.
Citrate Functionalized Zirconium-Based Metal Organic Framework for the Fluorescent Detection of Ciprofloxacin in Aqueous Media
Authors: Liu Bo-Tau , Nagarajan Dillirani , Kaliyamoorthy Selvam , Rathinam Balamurugan
Published: November 2022

Ciprofloxacin (CIP) is a commonly used antibiotic for the treatment of infectious diseases in humans and as a prophylactic agent in the livestock industry, leading to the environmental discharge of significant amounts of CIP. CIP is stable in aquatic systems leading to its pseudo-persistence. Constant exposure to these antibiotics results in the generation of antibiotic-resistant pathogens and potential toxicity/hypersensitivity in humans. Therefore, it is necessary to develop a convenient, rapid, and cost-effective method for the monitoring of ciprofloxacin in environmental samples. Rhodamine-based fluorescent receptors have the limitation of aqueous solubility. Therefore, in order to overcome this drawback, we designed a novel fluorescent receptor based on a zirconium-based metal organic framework (MOF-808). The precursor, MOF-808, was synthesized and functionalized by using sodium citrate to obtain a receptor called C-MOF-808. The C-MOF-808 was structurally characterized by XRD and spectroscopic analyses. Thus, this synthesized receptor can be used for the fluorescent detection of CIP in aqueous media with a detection limit of 9.4 µM. The detection phenomena of the receptor were studied by absorption as well as fluorescent spectra. The binding behavior of CIP with the receptor was studied by FT-IR and 1H-NMR analyses, and a binding mechanism is proposed.
Influencing Effects of Fabrication Errors on Performances of the Dielectric Metalens
Authors: Xu Guoqing , Kang Qianlong , Fan Xueqiang , Yang Guanghui , Guo Kai , Guo Zhongyi
Published: November 2022

Despite continuous developments of manufacturing technology for micro-devices and nano-devices, fabrication errors still exist during the manufacturing process. To reduce manufacturing costs and save time, it is necessary to analyze the effects of fabrication errors on the performances of micro-/nano-devices, such as the dielectric metasurface-based metalens. Here, we mainly analyzed the influences of fabrication errors in dielectric metasurface-based metalens, including geometric size and shape of the unit element, on the focusing efficiency and the full width at half maximum (FWHM) values. Simulation results demonstrated that the performance of the metasurface was robust to fabrication errors within a certain range, which provides a theoretical guide for the concrete fabrication processes of dielectric metasurfaces.
The Electrical and Thermal Characteristics of Stacked GaN MISHEMT
Authors: Hui Caixin , Chen Qiuqi , Shi Yijun , He Zhiyuan , Huang Yun , Lu Xiangjun , Wang Hongyue , Jiang Jie , Lu Guoguang
Published: November 2022

To study the working performance of 3D stacked chips, a double-layer stacked GaN MISHEMTs structure was designed to study the electro-thermal characteristics and heat transfer process of stacked chips. Firstly, the electrical characteristics of double-layer and single-layer GaN MISHEMTs are compared at room temperature. Under the same conditions, the output current of double-layer GaN MISHEMTs is twice that of single-layer GaN MISHEMTs, but its off-state current is much higher than that of a single-layer device. Meanwhile, there is no significant difference between the threshold voltages of the double-layer and single-layer GaN MISHEMTs. Then, the effect of temperature on the electrical characteristics of double-layer GaN MISHEMTs is also investigated. When the temperature increased from room temperature to 150 °C, the device’s threshold voltage gradually shifted negatively, the output current of the device decreased, and the off-state current of the device increased. Furthermore, a thermal resistance network model has been established to analyze the thermal characteristics of the stacked GaN MISHEMTs. The relative error between the results calculated according to the model and the experimental results does not exceed 4.26%, which verified the correctness and accuracy of the presented model to predict the temperature distribution of the stacked GaN MISHEMTs.
Valorization of South African Coal Wastes through Dense Medium Separation
Authors: Amaral Filho Juarez R. do , Gcayiya Msimelelo , Kotsiopoulos Athanasios , Broadhurst Jennifer L. , Power David , Harrison Susan T. L.
Published: November 2022

Sustainable management of coal waste is one of the major environmental concerns for coal mining, whether active or legacy, worldwide. Coal dump deposits demand a large physical area or footprint for disposal of solid waste, change the topography, and generate both pyritic dust and acid rock drainage (ARD) where pyritic coal waste is deposited. The beneficiation of dump deposits or, preferably, of coal waste prior to its dumping can reduce or even eliminate the liabilities related to coal waste management. In this work, dense medium separation studies of coal discards, using heavy liquids, resulted in three pooled fractions from typical South African coal waste discards from the Mpumalanga region for future use: (a) a fraction of low density with increased calorific value; (b) a fraction of intermediate density, rich in ash and acid neutralizing minerals and lower in sulfur; and (c) a fraction of high density, rich in sulfidic minerals including pyrite. The fractions were characterized using particle size analysis, sink-float studies, static tests to predict ARD potential, proximateand ultimate analysis, and gross calorific value. The results showed that approximately 70% of this discard coal is composed of a material of sufficient quality for energy generation in conventional power stations. A pyrite-rich concentrate made up 2% of the total discard mass; comprising more than 45% of the sulfidic mineral present in the feed and displaying no acid neutralizing capacity (ANC). The remaining discard fraction, with intermediate density, presented potential to be used for several ends including soil fabrication, co-disposal or as aggregate material in civil engineering; additional testing to ensure applicability for the selected re-purposing option should be chosen based on proposed use.
Investigating the Influence of the Electrochemical Environment on the Flotation of Bornite and Chalcocite
Authors: Tafirenyika Tanaka P. , O’Connor Cyril T. , Corin Kirsten C.
Published: November 2022

Beneficiation of sulphide ores by flotation is ascribed to the natural electrochemical activity associated with sulphide minerals. Flotation is an electrochemical process comprising many interdependent conditions that are difficult to decouple in terms of controlling flotation performance. The extent of electrochemical activity is mineral dependent and can be measured against a reference cell to differentiate between minerals. This difference in activity is known as the rest potential. The rest potential can be exploited to preferentially float one mineral over another as these properties result in different regions of flotation stability for different minerals. Bornite and chalcocite present an interesting study because when measured against the standard hydrogen electrode (SHE), there is a small difference in rest potential; bornite has a potential of 0.44 V and chalcocite a potential of 0.40 V. The key differentiating factor between the two minerals is the presence of iron in bornite (Cu5FeS4) and the lack thereof in chalcocite (Cu2S). This study considers bornite and chalcocite microflotation, adsorption studies and zeta potential measurements, and three key factors were explored: pH, galvanic interactions and collector adsorption. The overall objective of the study is to understand the response of bornite and chalcocite to changes in pulp chemistry.
Urea Synthesis from Isocyanides and O-Benzoyl Hydroxylamines Catalyzed by a Copper Salt
Authors: Yu Ning , Lv Jing-Fang , He Shi-Mei , Cui Yanyan , Wei Ye , Jiang Kun
Published: November 2022

In the presence of CuOAc, a series of unsymmetric ureas can be generated in moderate to good yields under mild reaction conditions (10 mol% of CuOAc, 2 equiv t-BuONa or PhONa, 30 °C), using aryl isocyanides and O-benzoyl hydroxylamines as the readily accessible starting materials. The reactions might undergo a cascade process involving isocyanide insertion into the N-O bond and Mumm-type rearrangement. This work represents a rare example of isocyanide insertion into N-O bonds, which would extend isocyanide insertion chemistry.
Chemical Composition, Phytotoxic and Antibiofilm Activity of Seven Eucalyptus Species from Tunisia
Authors: Khedhri Sana , Polito Flavio , Caputo Lucia , Manna Francesco , Khammassi Marwa , Hamrouni Lamia , Amri Ismail , Nazzaro Filomena , De Feo Vincenzo , Fratianni Florinda
Published: November 2022

This study was carried out to characterize the chemical composition of the essential oils from seven Eucalyptus species (E. griffithsii, E. hemiphloia, E. lesouefii, E. longicornis, E. pyriformis, E. viminalis, and E. wandoo), as well as their phytotoxic and antibacterial activities. The essential oils were analyzed by GC/MS and the potential in vitro phytotoxicity was evaluated against germination and radical elongation of Raphanus sativus, Lolium multiflorum, and Sinapis arvensis seeds. The antibiofilm activity was studied against both Gram-negative (Pseudomonas aeruginosa, Escherichia coli and Acinetobacter baumannii) and Gram-positive (Staphylococcus aureus and Listeria monocytogenes) bacteria. The inhibition of biofilm formation and its metabolism was determined at different times. Eucalyptol was the most abundant component in all essential oils studied (ranging from 40.8% for E. lesouefii EO to 73.6% for E. wandoo) except for that of E. pyriformis where it was present but at 15.1%. E. pyriformis was the most active against both germination and radical elongation of S. arvensis. The action of all essential oils proved to be highly effective in inhibiting the bacterial adhesion process of the five strains considered. In light of these results, these essential oils could have potential applications both in the agricultural and health fields.
Antioxidant Potential of Diosmin and Diosmetin against Oxidative Stress in Endothelial Cells
Authors: Wójciak Magdalena , Feldo Marcin , Borowski Grzegorz , Kubrak Tomasz , Płachno Bartosz J. , Sowa Ireneusz
Published: November 2022

Phlebotropic flavonoids, including diosmin and its aglycone diosmetin, are natural polyphenols widely used in the prevention and treatment of chronic venous insufficiency (CVI). As oxidative stress plays an important role in the development of pathophysiology of the cardiovascular system, the study aimed to investigate the protective effects of diosmin and diosmetin on hydrogen peroxide (H2O2)-induced oxidative stress in endothelial cells. The cells were pretreated with different concentrations of the flavonoid prior to the H2O2 exposure. The cell viability, the level of intracellular reactive oxygen species (ROS), the activity of cellular antioxidant enzymes—including superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase GPx—and the malondialdehyde (MDA) level were assessed. It was found that the H2O2-induced oxidative stress was ameliorated by diosmin/diosmetin in a concentration-dependent manner. The flavonoids restored the activity of cellular antioxidant enzymes and lowered the MDA level upregulated by the H2O2 exposure. These results indicate that diosmin and diosmetin may prevent oxidative stress in endothelial cells; therefore, they may protect against the development and progression of oxidative-stress-related disorders.
Supramolecular Diversity, Theoretical Investigation and Antibacterial Activity of Cu, Co and Cd Complexes Based on the Tridentate N,N,O-Schiff Base Ligand Formed In Situ
Authors: Buvaylo Elena A. , Nesterova Oksana V. , Goreshnik Evgeny A. , Vyshniakova Hanna V. , Petrusenko Svitlana R. , Nesterov Dmytro S.
Published: November 2022

The four new complexes, [Cu(HL1)(L2)Cl] (1), [Cu(HL1)(L1)]∙Cl∙2H2O (2), [Co(L1)2]∙Cl (3) and [Cd(HL1)I2]∙dmso (4), have been prepared by one-pot reactions of the respective chloride or iodide metal salt with a non-aqueous solution of the polydentate Schiff base, HL1, resulted from in situ condensation of benzhydrazide and 2-pyridinecarboxaldehyde, while a ligand HL2, in case of 1, has been formed due to the oxidation of 2-pyridinecarboxaldehyde under reaction conditions. The crystallographic analysis revealed that the molecular building units in 1–4 are linked together into complex structures by hydrogen bonding, resulting in 1D, 2D and 3D supramolecular architectures for 1, 2 and 4, respectively, and the supramolecular trimer for 3. The electronic structures of 1–4 were investigated by the DFT theoretical calculations. The non-covalent interactions in the crystal structures of 1–4 were studied by means of the Hirshfeld surface analysis and the QTAIM theory with a special focus on the C–H⋯Cl bonding. From the DFT/DLPNO-CCSD(T) calculations, using a series of charged model {R3C–H}0⋯Cl− assemblies, we propose linear regressions for assessment of the interaction enthalpy (ΔH, kcal mol−1) and the binding energy (BE, kcal mol−1) between {R3C–H}0 and Cl− sites starting from the electron density at the bond critical point (ρ(rBCP), a.u.): ΔH = −678 × ρ(r) + 3 and BE = −726 × ρ(r) + 4. It was also has been found that compounds 1, 3 and 4 during in vitro screening showed an antibacterial activity toward the nine bacteria species, comprising both Gram-positive and Gram-negative, with MIC values ranging from 156.2 to 625 mg/L. The best results have been obtained against Acinetobacter baumannii MβL.
Constructing a Visible-Active CoFe2O4@Bi2O3/NiO Nanoheterojunction as Magnetically Recoverable Photocatalyst with Boosted Ofloxacin Degradation Efficiency
Authors: Dhiman Pooja , Sharma Gaurav , Alodhayb Abdullah N. , Kumar Amit , Rana Garima , Sithole Thandiwe , ALOthman Zeid A.
Published: November 2022

Constructing visible-light-active Z-scheme heterojunctions has proven fruitful in enhancing the photocatalytic activity of photocatalysts for superior water clean-up. Herein, we report the fabrication of a CoFe2O4@Bi2O3/NiO (CBN) Z-scheme nanoheterojunction. The obtained CBN heterojunction was used for visible-light-assisted degradation of ofloxacin (OFL) in water. The OFL degradation efficiency achieved by the CBN heterojunction was 95.2% in 90 min with a rate constant of kapp = 0.03316 min−1, which was about eight times that of NiO and thirty times that of CoFe2O4. The photocatalytic activity of a Bi2O3/NiO Z-scheme heterojunction was greatly enhanced by the visible activity and redox mediator effect of the cobalt ferrite co-catalyst. Higher charge-carrier separation, more visible-light capture, and the Z-scheme mechanism in the Z-scheme system were the important reasons for the high performance of CBN. The scavenging experiments suggested ●O2− as an active species for superior OFL degradation. The possible OFL degradation pathway was predicted based on LC-MS findings of degradation intermediate products. The magnetic nature of the CBN helped in the recovery of the catalyst after reuse for six cycles. This work provides new insights into designing oxide-based heterojunctions with high visible-light activity, magnetic character, and high redox capabilities for potential practical applications in environmental treatment.
Lactobacillus paracasei HY7015 and Lycopus lucidus Turcz. Extract Promotes Human Dermal Papilla Cell Cytoprotective Effect and Hair Regrowth Rate in C57BL/6 Mice
Authors: Lee Hayera , Kim Hyeonji , Kim Ji-Hyun , Park Soo-Dong , Shim Jae-Jung , Lee Jeong-Lyoul
Published: November 2022

Hair loss is a disease that requires accurate diagnosis and type-specific medical treatment. Many hair loss treatments have some side effects, such as hormone-related effects, so there is a need for safe and effective hair loss treatment. In this study, we investigated the effects of Lactobacillus paracasei HY7015 (HY7015) and Lycopus lucidus Turcz. (LT) extract on hair regrowth and protection. In vitro experiments were conducted to assess the effects of HY7015 and/or LT extract on human follicle dermal papilla cells (HFDPC) of cytoprotective functions such as proliferations, antioxidants, anti-inflammatory, and growth factor expressions. In animal experiments, we investigated hair regrowth rate, hair follicle formation and secretion of growth factors in telogenic C57BL/6 mice. We confirmed the cytoprotective effects of HY7015 and LT through regulations of proliferation, SOD and IL-1β in HFDPC. In mouse experiments, oral administration of HY7015 and LT promoted hair regrowth as well as hair follicle maturation in the dermal skin of C57BL/6 mice, and upregulated VEGF and IGF-1 growth factor levels in mouse serum. In summary, our data demonstrate that ingestions of HY7015 and LT can promote hair regrowth by enhancing cytoprotective effects and expressions of growth factors.
The Therapeutic Effect and the Potential Mechanism of Flavonoids and Phenolics of Moringa oleifera Lam. Leaves against Hyperuricemia Mice
Authors: Luo Xiaowei , Zhou Lipeng , Wang Shukai , Yuan Jing , Chang Zihao , Hu Qian , Chen Yinxin , Liu Yuqi , Huang Ya , Wang Baojin , Gao Ye , Wang Zhaohui , Cui Yitong , Liu Yue , Zhang Lanzhen
Published: November 2022

The aim of this study is to evaluate the anti-hyperuricemia effect and clarify the possible mechanisms of flavonoids and phenolics of MOL (MOL-FP) in mice. Hyperuricemia mice were generated via intraperitoneal (i.p.) administration of potassium oxonate (PO) and oral gavage (p.o.) of hypoxanthine (HX). Serum uric acid (UA), weight, serum XO activity, hepatic XO activity, urea nitrogen (BUN), creatinine (CRE), serum AST level, serum ALT level, mRNA expression of renal urate-anion transporter 1 (URAT1), glucose transporter 9 (GLUT9), organic anion transporters 1 (OAT1), organic anion transporters 3 (OAT3), and ATP-binding cassette transporter G2 (ABCG2) were determined. The molecular docking was conducted using AutoDock Vina 1.2.0 to screen potential XO inhibitors in MOL-FP. Serum metabolomics was established to collect the metabolic profiles of mice and explore the metabolic changes that occurred after MOL-FP treatment. MOL-FP could notably reduce the serum UA level of hyperuricemia mice by inhibiting XO activity and regulating renal urate transporters. Molecular docking studies indicated that 5-p-coumaroylquinic acid, 3-p-coumaroylquinic acid, and catechin could be potential XO inhibitors. Besides, MOL-FP prevented the pathological process of hyperuricemia by regulating biomarkers associated with purine metabolism, amino acid metabolism, and lipid metabolism.
Synthesis and Characterization of Hydroxyethyl Cellulose Grafted with Copolymer of Polyaniline and Polypyrrole Biocomposite for Adsorption of Dyes
Authors: Bajaber Majed A. , Anjum Muhammad Naveed , Ibrahim Muhammad , Farooq Tahir , Ahmad Mirza Nadeem , Abideen Zain ul
Published: November 2022

The emerging concepts of sustainable textiles and controlled production strategy demands ideally zero emissions of contaminants into the aquatic environment. However, the currently in-practiced conventional processes in textiles dispose of a number of contaminants especially super toxic synthetic dyes as effluents. In recent years, nanomaterials have become attractive choice for eco-friendly removal of organic dyestuff. Accordingly, this article reports synthesis and characterization of biocomposite wherein copolymer of polyaniline (PANI) and Polypyrrole (PPY) was grafted onto hydroxyethyl cellulose (HEC). Further, adsorption properties of as-prepared composite were evaluated using textile dyes Rhodamine B (RhB) and methyl Orange (MO)- as model adsorbate. The characterization of novel biocomposite (HEC/PANI-PPy) was carried out using Fourier Transform Infrared (FT-IR), Brunauer-Emmett-Teller analyzer (BET), Scanning Electron Microscope (SEM), and powder X-ray diffraction (XRD). The operational parameters such as dye initial concentration, adsorbent amount, pH and contact time were also studied to evaluate the efficiency level of the prepared biocomposite. Interestingly, the composite-mediated adsorption of RhB and MO followed pseudo-second order and the Langmuir isotherm. It is found that the adsorption capacity HEC/PANI-PPy is 30.06 and 29.3 for RhB and MO respectively. Thus, HEC/PANI-PPy is an inexpensive and highly efficient adsorbent that could be employed for could be employed for the separation and removal of toxic organic dyes from polluted textile effluents.
Medicinal Properties of Anchusa strigosa and Its Active Compounds
Authors: Yarmolinsky Ludmila , Budovsky Arie , Khalfin Boris , Yarmolinsky Leonid , Ben-Shabat Shimon
Published: November 2022

Anchusa strigosa is a widespread weed in Greece, Syria, Turkey, Lebanon, Israel, Jordan, and Iran. The purpose of this study was to identify the phytochemicals of Anchusa strigose and estimate the pro-wound healing (pro-WH) and antimicrobial activities of its active compounds. An identification of volatile compounds was performed by GC/MS analysis; HPLC, LC-ESI-MS, and MALDI-TOF-MS were also applied. Our results demonstrate that two specific combinations of compounds from A. strigosa extract significantly enhanced WH (p < 0.001). Several flavonoids of the plant extract, including quercetin 3-O-rutinoside, kaempferol, kaempferol 3-O-β-rhamnopyranosyl(1→6)-β-glucopyranoside, and kaempferol 3-O-α-rhamnopyranosyl(1→6)-β-galactopyranoside, were effective against drug-resistant microorganisms. In addition, all the above-mentioned compounds had antibiofilm activity against Escherichia coli and Salmonella enteritidis.
Pseudognaphalium affine Extract Alleviates COPD by Inhibiting the Inflammatory Response via Downregulation of NF-κB
Authors: Ye Xiangli , Luo Shuping , Chang Xiaona , Fang Yaling , Liu Yaojun , Zhang Yuqin , Li Huang
Published: November 2022

Chronic obstructive pulmonary disease (COPD) is a chronic respiratory disease with limited therapeutic options. Pseudognaphalium affine (D. Don) Anderb. is a medicinal and edible plant used to treat cough, asthma, and COPD for a long time in folk medicine. The objective of this study is to evaluate the effect of Pseudognaphalium affine (D. Don) Anderb. extract (GAE) and investigate the possible underlying mechanism in vivo and in vitro. In vivo, the administration of GAE in a rat COPD model could significantly ameliorate lung damage and pulmonary function by inhibiting the production of pro-inflammatory cytokines. Western blot and real-time PCR results showed that GAE could suppress nuclear translocation of nuclear factor-kappa B (NF-κB), which indicated that GAE down-regulated the NF-κB pathway. Moreover, GAE protected against tumor necrosis factor (TNF)-α induced inflammatory response in BEAS-2B and inhibited the NF-κB pathway. All data suggested that GAE exhibited its anti-COPD effect by inhibiting pro-inflammatory cytokines, which may be associated with the inhibition of the NF-κB pathway.
A Mechanistic Study of Asymmetric Transfer Hydrogenation of Imines on a Chiral Phosphoric Acid Derived Indium Metal-Organic Framework
Authors: Li Xu , Fan Ting , Wang Qingji , Shi Tongfei
Published: November 2022

A density functional theory (DFT) study is reported to examine the asymmetric transfer hydrogenation (ATH) of imines catalyzed by an indium metal-organic framework (In-MOF) derived from a chiral phosphoric acid (CPA). It is revealed that the imine and reducing agent (i.e., thiazoline) are simultaneously adsorbed on the CPA through H-bonding to form an intermediate, subsequently, a proton is transferred from thiazoline to imine. The transition state TS-R and TS-S are stabilized on the CPA via H-bonding. Compared to the TS-S, the TS-R has shorter H-bonding distances and longer C-H···π distances, it is more stable and experiences less steric hindrance. Consequently, the TS-R exhibits a lower activation barrier affording to the (R)-enantiomer within 68.1% ee in toluene. Imines with substituted groups such as −NO2, −F, and −OCH3 are used to investigate the substitution effects on the ATH. In the presence of an electron-withdrawing group like −NO2, the electrophilicity of imine is enhanced and the activation barrier is decreased. The non-covalent interactions and activation-strain model (ASM) analysis reveal that the structural distortions and the differential noncovalent interactions of TSs in a rigid In-MOF provide the inherent driving force for enantioselectivity. For −OCH3 substituted imine, the TS-S has the strongest steric hindrance, leading to the highest enantioselectivity. When the solvent is changed from toluene to dichloromethane, acetonitrile, and dimethylsulfoxide with increasing polarity, the activation energies of transition state increase whereas their difference decreases. This implies the reaction is slowed down and the enantioselectivity becomes lower in a solvent of smaller polarity. Among the four solvents, toluene turns out to be the best for the ATH. The calculated results in this study are in fairly good agreement with experimental observations. This study provides a mechanistic understanding of the reaction mechanism, as well as substitution and solvent effects on the activity and enantioselectivity of the ATH. The microscopic insights are useful for the development of new chiral MOFs toward important asymmetric reactions.
Insights into the Dynamics and Binding of Two Polyprotein Substrate Cleavage Points in the Context of the SARS-CoV-2 Main and Papain-like Proteases
Authors: Sanusi Zainab Kemi , Lobb Kevin Alan
Published: November 2022

It is well known that vital enzymes in the replication process of the coronavirus are the SARS-CoV-2 PLpro and SARS-CoV-2 3CLpro, both of which are important targets in the search for anti-coronavirus agents. These two enzymes are responsible for cleavage at various polyprotein sites in the SARS-CoV-2 lifecycle. Herein, the dynamics of the polyprotein cleavage sequences for the boundary between non-structural proteins Nsp1 and Nsp2 (CS1) and between Nsp2 and Nsp3 (CS2) in complex with both the papain-like protein PLpro and the main protease 3CLpro were explored using computational methods. The post dynamics analysis reveals that CS1 and CS2 both have greater stability when complexed with PLpro. Of these two, greater stability is observed for the CS1–PLpro complex, while destabilization resulting in loss of CS2 from the PLpro active site is observed for CS2-PLpro, suggesting the rate of exchange by the papain-like protease is faster for CS2 compared to CS1. On the other hand, the 3CLpro main protease also reveals stability for CS1 suggesting that the main protease could also play a potential role in the cleavage at point CS1. However, destabilization occurs early in the simulation for the complex CLpro–CS2 suggesting a poor interaction and non-plausible protease cleavage of the polyprotein at CS2 by the main protease. These findings could be used as a guide in the development and design of potent COVID-19 antiviral inhibitors that mimic the CS1 cleavage site.
Synthetic Exploration of Bis(phenolate) Aza-BODIPYs and Heavier Group 13 Chelates
Authors: Lane Aiden M. , Luong Ny T. C. , Kelly Jordan C. , Neal Martin J. , Jamrom Jeremiah , Bloomfield Aaron J. , Lummis Paul A. , Montgomery Thomas D. , Chase Daniel T.
Published: November 2022

A series of boron, aluminum, gallium, and indium chelates containing the underexplored bis(phenolate) aza-dipyrromethene (aza-DIPY) core were prepared. These compounds were found to possess near-infrared absorption and emission profiles in the 710 to 770 nm domain and exhibit quantum yield values up to 14%. X-ray diffraction analysis revealed that heavier group 13 bis(phenolate) aza-DIPY chelates possessed octahedral geometries with either THF or pyridine groups occupying the axial positions as opposed to the tetrahedral geometry of the boron chelate.
Progress on COVID-19 Chemotherapeutics Discovery and Novel Technology
Authors: Zhou Yalan , Wang Huizhen , Yang Li , Wang Qingzhong
Published: November 2022

COVID-19 is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a novel highly contagious and pathogenic coronavirus that emerged in late 2019. SARS-CoV-2 spreads primarily through virus-containing droplets and small particles of air pollution, which greatly increases the risk of inhaling these virus particles when people are in close proximity. COVID-19 is spreading across the world, and the COVID-19 pandemic poses a threat to human health and public safety. To date, there are no specific vaccines or effective drugs against SARS-CoV-2. In this review, we focus on the enzyme targets of the virus and host that may be critical for the discovery of chemical compounds and natural products as antiviral drugs, and describe the development of potential antiviral drugs in the preclinical and clinical stages. At the same time, we summarize novel emerging technologies applied to the research on new drug development and the pathological mechanisms of COVID-19.
SnCl4 Promoted Efficient Cleavage of Acetal/Ketal Groups with the Assistance of Water in CH2Cl2
Authors: Luo Tao , Xu Tian-Tian , Guo Yang-Fan , Dong Hai
Published: November 2022

Acetalization and deacetalation are a pair of routine manipulations to protect and deprotect the 4- and 6-hydroxyl groups of glycosides in the synthesis of glycosyl building blocks. In this study, we found that treatment of SnCl4 with various carbohydrates containing acetal/ketal groups with the assistance of water in CH2Cl2 led to deacetalization/deketalization products in almost quantitative yields. In addition, for substrates containing both acetal/ketal and p-methoxylbenzyl groups, we also found that the p-methoxylbenzyl group was selectively cleaved by the use of a catalytic amount of SnCl4, while the acetal/ketal groups remained. Furthermore, based on this, 4,6-benzylidene glycosides can be conveniently converted to 4,6-OAc or 4-OH, 6-OAc glycosides.
Facile Synthesis of Highly Emissive All-Inorganic Manganese Bromide Compounds with Perovskite-Related Structures for White LEDs
Authors: Gao Ping , Cheng Suwen , Liu Jiaxin , Li Junjie , Guo Yanyan , Deng Zhengtao , Qin Tianshi , Wang Aifei
Published: November 2022

Lead-free all-inorganic halide materials with different Mn2+-based crystal structures (Cs3MnBr5 and CsMnBr3) were obtained using a convenient synthetic method. Cs3MnBr5 had a bright green emission (522 nm), with a unique single-exponential lifetime (τavg = 236 µs) and a high photoluminescence quantum yield (82 ± 5%). A red emission was observed in the case of the CsMnBr3 structure with a two-exponential fluorescence decay curve, and the lifetime was 1.418 µs (93%) and 18.328 µs (7%), respectively. By a judicious tuning of the synthetic conditions, a mixed phase of Cs3MnBr5/CsMnBr3 was also produced that emitted white light, covering almost the entire visible spectrum. White-light-emitting diodes (WLEDs) with color coordinates (0.4269, 0.4955), a color temperature of (3773 K), and a color rendering index (68) were then fabricated using the as-prepared powder of mixed phases of Cs3MnBr5/CsMnBr3 with a commercial UV LED chip (365 nm).
Shikonin as a WT1 Inhibitor Promotes Promyeloid Leukemia Cell Differentiation
Authors: Guo Zhenzhen , Sun Luyao , Xia Haojie , Tian Shibin , Liu Mengyue , Hou Jiejie , Li Jiahuan , Lin Haihong , Du Gangjun
Published: November 2022

This study aims to observe the differentiating effect of shikonin on Wilms’ tumor 1 (WT1)-positive HL-60 cells and investigate the fate of the differentiated leukemia cells. WT1 overexpression unaffected cell viability but promoted resistance to H2O2-induced DNA injury and cell apoptosis. The binding of shikonin to the WT1 protein was confirmed by molecular docking and drug affinity reaction target stability (DARTS). Shikonin at the non-cytotoxic concentration could decrease the WT1 protein and simultaneously reduced the CD34 protein and increased the CD11b protein in a dose-dependent manner in normal HL-60 cells but not in WT1-overexpressed HL-60 cells. Shikonin unaffected HL-60 cell viability in 48 h. However, it lasted for 10 days; could attenuate cell proliferation, mitochondrial membrane potential (MMP), and self-renewal; prevent the cell cycle; promote cell apoptosis. In a mouse leukemia model, shikonin could decrease the WT1 protein to prevent leukemia development in a dose-dependent manner. In this study, we also confirmed preliminarily the protein–protein interactions between WT1 and CD34 in molecular docking and CO-IP assay. Our results suggest that: 1. shikonin can down-regulate the WT1 protein level for leukemia differentiation therapy, and 2. the interaction between WT1 and CD34 proteins may be responsible for granulocyte/monocyte immaturity in HL-60 cells.
Uptake, Translocation, and Fate of Carcinogenic Aristolochic Acid in Typical Vegetables in Soil−Plant Systems
Authors: Zhang Jinghe , Wang Yinan , Wang Changhong , Li Kan , Tang Weifang , Sun Jing , Wang Xikui
Published: November 2022

When Aristolochia plants wilt and decay, aristolochic acids (AAs) are released into the soil, causing soil contamination. It has been demonstrated that aristolochic acid can be accumulated and enriched in crops through plant uptake. However, there is a lack of systematic studies on the migration and accumulation of AAs in a realistic simulated soil environment. In this study, Aristolochia herbal extracts were mixed with soil for growing three typical vegetables: lettuce, celery, and tomato. The contents of AAs in the above-mentioned plants were determined by an established highly sensitive LC-MS/MS method to study the migration and accumulation of AAs. We found that AAs in the soil can be transferred and accumulated in plants. AAs first entered the roots, which were more likely to accumulate AAs, and partially entered the above-ground parts. This further confirms that AAs can enter the food chain through plants and can have serious effects on human health. It was also shown that plants with vigorous growth and a large size absorbed AAs from the soil at a faster rate. The more AAs present in the soil, the more they accumulated in the plant.
Induction of Apoptosis via Inactivating PI3K/AKT Pathway in Colorectal Cancer Cells Using Aged Chinese Hakka Stir-Fried Green Tea Extract
Authors: Zhang Xinyue , Huang Haiying , Sun Shili , Li Dongli , Sun Lingli , Li Qiuhua , Chen Ruohong , Lai Xingfei , Zhang Zhenbiao , Zheng Xi , Wong Wing-Leung , Wen Shuai
Published: November 2022

Food extract supplements, with high functional activity and low side effects, play a recognized role in the adjunctive therapy of human colorectal cancer. The present study reported a new functional beverage, which is a type of Chinese Hakka stir-fried green tea (HSGT) aged for several years. The extracts of the lyophilized powder of five HSGT samples with different aging periods were analyzed with high-performance liquid chromatography. The major components of the extract were found to include polyphenols, catechins, amino acids, catechins, gallic acid and caffeine. The tea extracts were also investigated for their therapeutic activity against human colorectal cancer cells, HT-29, an epithelial cell isolated from the primary tumor. The effect of different aging time of the tea on the anticancer potency was compared. Our results showed that, at the cellular level, all the extracts of the aged teas significantly inhibited the proliferation of HT-29 in a concentration-dependent manner. In particular, two samples prepared in 2015 (15Y, aged for 6 years) and 2019 (19Y, aged for 2 years) exhibited the highest inhibition rate for 48 h treatment (cell viability was 50% at 0.2 mg/mL). Further, all the aged tea extracts examined were able to enhance the apoptosis of HT-29 cells (apoptosis rate > 25%) and block the transition of G1/S phase (cell-cycle distribution (CSD) from <20% to >30%) population to G2/M phase (CSD from nearly 30% to nearly 10%) at 0.2 mg/mL for 24 h or 48 h. Western blotting results also showed that the tea extracts inhibited cyclin-dependent kinases 2/4 (CDK2, CDK4) and CylinB1 protein expression, as well as increased poly ADP-ribose polymerase (PRAP) expression and Bcl2-associated X (Bax)/B-cell lymphoma-2 (Bcl2) ratio. In addition, an upstream signal of one of the above proteins, phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signalling, was found to be involved in the regulation, as evidenced by the inhibition of phosphorylated PI3K and AKT by the extracts of the aged tea. Therefore, our study reveals that traditional Chinese aged tea (HSGT) may inhibit colon cancer cell proliferation, cell-cycle progression and promoted apoptosis of colon cancer cells by inactivating PI3K/AKT signalling.
Rethinking Electronic Effects in Photochemical Hydrogen Evolution Using CuInS2@ZnS Quantum Dots Sensitizers
Authors: Orlando Antonio , Lucarini Fiorella , Benazzi Elisabetta , Droghetti Federico , Ruggi Albert , Natali Mirco
Published: November 2022

Molecular catalysts based on coordination complexes for the generation of hydrogen via photochemical water splitting exhibit a large versatility and tunability of the catalytic properties through chemical functionalization. In the present work, we report on light-driven hydrogen production in an aqueous solution using a series of cobalt polypyridine complexes as hydrogen evolving catalysts (HECs) in combination with CuInS2@ZnS quantum dots (QDs) as sensitizers, and ascorbate as the electron donor. A peculiar trend in activity has been observed depending on the substituents present on the polypyridine ligand. This trend markedly differs from that previously recorded using [Ru(bpy)3]2+ (where bpy = 2,2’-bipyridine) as the sensitizer and can be ascribed to different kinetically limiting pathways in the photochemical reaction (viz. protonation kinetics with the ruthenium chromophore, catalyst activation via electron transfer from the QDs in the present system). Hence, this work shows how the electronic effects on light-triggered molecular catalysis are not exclusive features of the catalyst unit but depend on the whole photochemical system.
Construction of 5-(Alkylamino)-6-aryl/alkylpyrazine-2,3-dicarbonitriles via the One-Pot Reaction of Alkyl Isocyanides with Aryl/Alkyl Carbonyl Chlorides and Diaminomaleonitrile: Fluorescence and Antimicrobial Activity Evaluation
Authors: Al-Azmi Amal , John Elizabeth
Published: November 2022

5-(Alkylamino)-6-aryl/alkylpyrazine-2,3-dicarbonitriles were successfully synthesized in good to moderate yields by reacting alkyl isocyanides with aryl/alkyl carbonyl chlorides, followed by the addition of diaminomaleonitrile. The synthesized pyrazines were fully characterized in this investigation, and X-ray crystal structure analysis was performed on some derivatives. The antibacterial and antifungal activities of the newly synthesized pyrazine-2,3-dicarbonitriles were assessed in addition to their UV and fluorescence results. All the compounds showed similar UV–Vis spectral features with absorption peaks (λmax) around 267, 303, and 373 nm.
Lead/Drug Discovery from Natural Resources
Authors: Xu Zhihong , Eichler Barrett , Klausner Eytan A. , Duffy-Matzner Jetty , Zheng Weifan
Published: November 2022

Natural products and their derivatives have been shown to be effective drug candidates against various diseases for many years. Over a long period of time, nature has produced an abundant and prosperous source pool for novel therapeutic agents with distinctive structures. Major natural-product-based drugs approved for clinical use include anti-infectives and anticancer agents. This paper will review some natural-product-related potent anticancer, anti-HIV, antibacterial and antimalarial drugs or lead compounds mainly discovered from 2016 to 2022. Structurally typical marine bioactive products are also included. Molecular modeling, machine learning, bioinformatics and other computer-assisted techniques that are very important in narrowing down bioactive core structural scaffolds and helping to design new structures to fight against key disease-associated molecular targets based on available natural products are considered and briefly reviewed.
Computer- and NMR-Aided Design of Small-Molecule Inhibitors of the Hub1 Protein
Authors: Reyes Romero Atilio , Kubica Katarzyna , Kitel Radoslaw , Rodríguez Ismael , Magiera-Mularz Katarzyna , Dömling Alexander , Holak Tad , Surmiak Ewa
Published: November 2022

By binding to the spliceosomal protein Snu66, the human ubiquitin-like protein Hub1 is a modulator of the spliceosome performance and facilitates alternative splicing. Small molecules that bind to Hub1 would be of interest to study the protein-protein interaction of Hub1/Snu66, which is linked to several human pathologies, such as hypercholesterolemia, premature aging, neurodegenerative diseases, and cancer. To identify small molecule ligands for Hub1, we used the interface analysis, peptide modeling of the Hub1/Snu66 interaction and the fragment-based NMR screening. Fragment-based NMR screening has not proven sufficient to unambiguously search for fragments that bind to the Hub1 protein. This was because the Snu66 binding pocket of Hub1 is occupied by pH-sensitive residues, making it difficult to distinguish between pH-induced NMR shifts and actual binding events. The NMR analyses were therefore verified experimentally by microscale thermophoresis and by NMR pH titration experiments. Our study found two small peptides that showed binding to Hub1. These peptides are the first small-molecule ligands reported to interact with the Hub1 protein.
A Newly Identified Monoterpenoid-Based Small Molecule Able to Support the Survival of Primary Cultured Dopamine Neurons and Alleviate MPTP-Induced Toxicity In Vivo
Authors: Kotliarova Anastasiia , Podturkina Alexandra V. , Pavlova Alla V. , Gorina Daria S. , Lastovka Anastasiya V. , Ardashov Oleg V. , Rogachev Artem D. , Izyurov Arseniy E. , Arefieva Alla B. , Kulikov Alexander V. , Tolstikova Tatyana G. , Volcho Konstantin P. , Salakhutdinov Nariman F. , Sidorova Yulia
Published: November 2022

Parkinson’s disease (PD) is the most common age-related movement disorder characterized by the progressive loss of nigrostriatal dopaminergic neurons. To date, PD treatment strategies are mostly based on dopamine replacement medicines, which can alleviate motor symptoms but do not slow down the progression of neurodegeneration. Thus, there is a need for disease-modifying PD therapies. The aim of this work was to evaluate the neuroprotective effects of the novel compound PA96 on dopamine neurons in vivo and in vitro, assess its ability to alleviate motor deficits in MPTP- and haloperidol-based PD models, as well as PK profile and BBB penetration. PA96 was synthesized from (1R,2R,6S)-3-methyl-6-(prop-1-en-2-yl) cyclohex-3-ene-1,2-diol (Prottremin) using the original three-step stereoselective procedure. We found that PA96: (1) supported the survival of cultured näive dopamine neurons; (2) supported the survival of MPP+-challenged dopamine neurons in vitro and in vivo; (3) had chemically appropriate properties (synthesis, solubility, etc.); (4) alleviated motor deficits in MPTP- and haloperidol-based models of PD; (5) penetrated the blood–brain barrier in vivo; and (6) was eliminated from the bloodstream relative rapidly. In conclusion, the present article demonstrates the identification of PA96 as a lead compound for the future development of this compound into a clinically used drug.
Whether the Research on Ethanol–Water Microstructure in Traditional Baijiu Should Be Strengthened?
Authors: Qin Dan , Shen Yi , Yang Shiqi , Zhang Guihu , Wang Dongmei , Li Hehe , Sun Jinyuan
Published: November 2022

Baijiu is a unique and traditional distilled liquor in China. Flavor plays a crucial rule in baijiu. Up to now, the research on the flavor of baijiu has progressed from the identification of volatile compounds to the research on key aroma compounds, but the release mechanism of these characteristic compounds is still unclear. Meanwhile, volatile compounds account for only a tiny fraction, whereas ethanol and water account for more than 98% of the content in baijiu. By summarizing the ethanol–water hydrogen bond structure in different alcoholic beverages, it was found that flavor compounds can affect the association strength of the ethanol–water hydrogen bond, and ethanol–water can also affect the interface distribution of flavor compounds. Therefore, the research on ethanol–water microstructure in baijiu is helpful to realize the simple visualization of adulteration detection, aging determination and flavor release mechanism analysis of baijiu, and further uncover the mystery of baijiu.
Anticancer Activity of (±)-Kusunokinin Derivatives towards Cholangiocarcinoma Cells
Authors: Rattanaburee Thidarath , Sermmai Patpanat , Tangthana-umrung Kornthip , Thongpanchang Tienthong , Graidist Potchanapond
Published: November 2022

This study aimed to investigate the cytotoxicity and anticancer activity of (±)-kusunokinin derivatives ((±)-TTPG-A and (±)-TTPG-B). The cytotoxicity effect was performed on human cancer cells, including breast cancer, cholangiocarcinoma, colon and ovarian cancer-cells, compared with normal cells, using the MTT assay. Cell-cycle arrest and apoptosis were detected using flow-cytometry analysis. We found that (±)-TTPG-B exhibited the strongest cytotoxicity on aggressive breast-cancer (MDA-MB-468 and MDA-MB-231) and cholangiocarcinoma (KKU-M213), with an IC50 value of 0.43 ± 0.01, 1.83 ± 0.04 and 0.01 ± 0.001 µM, respectively. Interestingly, (±)-TTPG-A and (±)-TTPG-B exhibited less toxicity than (±)-kusunokinin (9.75 ± 0.39 µM) on L-929 cells (normal fibroblasts). Moreover, (±)-TTPG-A predominated the ell-cycle arrest at the S phase, while (±)-TTPG-B caused cell arrest at the G0/G1 phase, in the same way as (±)-kusunokinin in KKU-M213 cells. Both (±)-TTPG-A and (±)-TTPG-B induced apoptosis and multi-caspase activity more than (±)-kusunokinin. Taken together, we conclude that (±)-TTPG-A and (±)-TTPG-B have a strong anticancer effect on cholangiocarcinoma. Moreover, (±)-TTPG-B could be a potential candidate compound for breast cancer and cholangiocarcinoma in the future.