Semisynthetic Derivatives of Sissotrin Isolated from Trifolium baccarinii Chiov. (Fabaceae) and Evaluation of Their Antibacterial Activities

Starting from sissotrin (1), a natural isoflavonoid isolated from Trifolium baccarinii (Fabaceae), one new semisynthetic derivative, 6-nitrobiochanin A (1b) and two known derivatives, 8-nitrobiochanin A (1a) and 2",3",4",6"-tetraacetylsissotrin (1c) have been obtained after performing nitration and acetylation reactions. Their structures were assigned after interpretation of their spectrometric (HR-ESI-MS) and spectroscopic (NMR 1D and 2D) data and by comparison with those reported in the literature. The substrate as well as the semisynthetic derivatives were evaluated for their antibacterial activities against six strains. The results reveal that they are inactive or weakly active on the strains tested with the exception of 8-nitrobiochanin A (1a) which showed moderate activity (MIC = 62.5 μg∙mL−1) on Staphylococcus aureus ATCC 43300.

Design, synthesis, and nanoengineered modification of spherical graphene surface by layered double hydroxide (LDH) for removal of As (Ⅲ) from aqueous solutions

In this study, new nano spherical graphene modified with LDH(Layered Double Hydroxide) was prepared and used to remove As(Ⅲ) ion from aqueous solutions. At first, graphene oxide was synthesized from graphite using a well-known Hammer method. The obtained graphene oxide solution was sprayed in octanol solution under different temperatures and sprayed speed as influenced variables. The structure and physical characterization of synthesized spherical graphene oxide were determined by various techniques,including FT-IR, N_(2) adsorption–desorption, SEM, TEM, and EDX. In the next step, the hydrothermal method was applied to deposition LDH on the spherical graphene oxide. The synthesized spherical graphene modified by LDH was used to remove As(Ⅲ) as a toxic heavy metal ion. The effect of influenced variables including p H, contact time, amount of sorbent, and type eluent studied and the optimum values were as 8, 30, 50, and HCl(0.5 mol·L^(-1)), respectively. After optimization, the studied sorbent was shown a high adsorption capacity(149.3 mg·g^(-1)). The adsorption mechanism and kinetic models exhibited good agreement with the Langmuir isotherm and pseudo-second-order trends, respectively. Besides, the synthesized product was tested for seven times without significant loss in its sorption efficiency.

Remote Teaching of Experimental Chemistry in Developing Countries

During the ongoing 2020 CoVid-19 crisis,the use of remote meeting technologies such as Zoom™,Microsoft Teams™and Google Meetings™has been paramount to theoretical teaching in a safe socially distanced environment.However,several problems arise when there is a need for an experimental approach.This paper looks at one of the possible solutions,including how to best separate the students,how to minimize close interactions and how a mixed environment of remote/presential teaching is required,minimizing the amount of extra materials,resources and protection equipment required,such that developing countries can quickly adopt this method,without the purchase of any external equipment.

The enantioselective enhancing effect and mechanistic insights of chiral enhancers in transdermal drug delivery

Overlook of chiral consideration in transdermal drug delivery increases administrated dose and risk of side effects,decreasing therapeutical effects.To improve the transdermal delivery efficiency of eutomer,this work focused on investigating the law and mechanism of enantioselective enhancing effects of chiral permeation enhancers on drug enantiomers.Chiral nonsteroidal anti-inflammatory drugs and terpene permeation enhancers were selected as model drug and enhancers.The results indicated that the L-isomer of permeation enhancers increased the skin absorption of S-enantiomer of drug and D-isomer improve the permeation of R-enantiomer,in which the enhancement effect(ER)of Lmenthol on S-enantiomer(ER=3.23)was higher than that on R-enantiomer(ER=1.49).According to the pharmacokinetics results,L-menthol tended to enhance the permeation of S-enantiomer better than R-enantiomer(2.56 fold),and showed excellent in vitro/in vivo correlations.The mechanism study showed that L-isomer of permeation enhancers improved the permeation of S-enantiomer by increasing the retention,but the D-isomer by improving partition for better permeation.Enantioselective mechanism indicated that the weaker chiral H-bond interaction between drug-chiral enhancers was caused by the enantiomeric conformation.Additionally,stronger chiral enhancers-skin interaction between L-isomer and S-conformation of ceramide produced better enhancing effects.In conclusion,enantioselective interaction of chiral drug-chiral enhancers and chiral enhancers-chiral skin played a critical role in transdermal drug delivery,rational utilization of which contributed to improving the uptake of eutomer and inhibiting distomers to decrease a half of dose and side effects,increasing transdermal therapeutical efficiency.

Meta-analysis of CO_(2) conversion,energy efficiency,and other performance data of plasma-catalysis reactors with the open access PIONEER database

This paper brings the comparison of performances of CO_(2)conversion by plasma and plasma-assisted catalysis based on the data collected from literature in this field,organised in an open access online database.This tool is open to all users to carry out their own analyses,but also to contributors who wish to add their data to the database in order to improve the relevance of the comparisons made,and ultimately to improve the efficiency of CO_(2)conversion by plasma-catalysis.The creation of this database and database user interface is motivated by the fact that plasma-catalysis is a fast-growing field for all CO_(2)conversion processes,be it methanation,dry reforming of methane,methanolisation,or others.As a result of this rapid increase,there is a need for a set of standard procedures to rigorously compare performances of different systems.However,this is currently not possible because the fundamental mechanisms of plasma-catalysis are still too poorly understood to define these standard procedures.Fortunately however,the accumulated data within the CO_(2)plasma-catalysis community has become large enough to warrant so-called“big data”studies more familiar in the fields of medicine and the social sciences.To enable comparisons between multiple data sets and make future research more effective,this work proposes the first database on CO_(2)conversion performances by plasma-catalysis open to the whole community.This database has been initiated in the framework of a H_(2)0_(2)0 European project and is called the“PIONEER Data Base”.The database gathers a large amount of CO_(2)conversion performance data such as conversion rate,energy efficiency,and selectivity for numerous plasma sources coupled with or without a catalyst.Each data set is associated with metadata describing the gas mixture,the plasma source,the nature of the catalyst,and the form of coupling with the plasma.Beyond the database itself,a data extraction tool with direct visualisation features or advanced filtering functionalities has been developed and is available online to the public.The simple and fast visualisation of the state of the art puts new results into context,identifies literal gaps in data,and consequently points towards promising research routes.More advanced data extraction illustrates the impact that the database can have in the understanding of plasma-catalyst coupling.Lessons learned from the review of a large amount of literature during the setup of the database lead to best practice advice to increase comparability between future CO_(2)plasma-catalytic studies.Finally,the community is strongly encouraged to contribute to the database not only to increase the visibility of their data but also the relevance of the comparisons allowed by this tool.

Physico-Chemical Study of the Adsorption of Carotenoids from Carrots on Raw and Modified Kaolinites

This study focuses on the adsorption at temperatures below 70℃, of carotenoids from carrots on clay materials such as kaolinite in the raw state, activated with a 0.5 M HCl solution or treated with a sodium solution of Al+. The kinetic study of carotenoid adsorption shows that equilibrium is reached after 30 minutes and the temperature has little influence on carotenoid adsorption. On the other hand, the quantities adsorbed at equilibrium increase with the initial concentration of carotenoids. The kinetic model that best describes the experimental data is that of the pseudo-second order, adsorption is made in two time. For the carotenoid adsorption isotherms, the best correlation is obtained with the Freundlich model. The low values of the Freundlich constants indicate that the adsorption is probably of a physical type. This conclusion is confirmed by the effective desorption of carotenoids observed during desorption experiments.

基于聚合物分散液晶的频率可重构贴片天线

本文设计了一种以液晶聚合物为介质基板的频率可重构天线,通过调节贴片的位置及尺寸实现天线的阻抗匹配。制备聚合物分散液晶薄膜作为天线的介质,并根据液晶与聚合物的比例分别为7∶3、6∶4、5∶5这3种不同配比以及50μm和100μm两种不同膜的厚度来考察其效果。在电场作用下,液晶微滴会沿着电场方向重新取向排列,通过改变驱动电压的大小,实现天线的频率可重构。经过对比分析得出,液晶含量(质量分数)为70%的聚合物分散液晶薄膜具有最佳的效果,在48 V的驱动电压下实现了62 MHz的频率连续调节,天线的最大增益为3.5 dBi。该基于液晶聚合物的频率可重构贴片天线结构简单、体积小、质量轻,易于集成在各种移动设备中,发展前景广阔。

Pathophysiological and clinical aspects of gastric hyperplastic polyps

Gastric polyps become a major clinical problem because of high prevalence and tendency to malignant transformation of some of them. The development of gastric hyperplastic polyps results from excessive proliferation of foveolar cells accompanied by their increased exfoliation, and they are macroscopically indistinguishable from other polyps with lower or higher malignant potential. Panendoscopy allows detection and differentiation of gastric polyps, usually after obtaining histopathological biopsy specimens. Unremoved gastric hyperplastic polyps may enlarge and sometimes spontaneously undergo a sequential progression to cancer. For this reason, gastric hyperplastic polyps larger than 5 mm in size should be removed in one piece. After excision of polyps with atypical focal lesion, endoscopic surveillance is suggested depending on histopathological diagnosis and possibility of confirming the completeness of endoscopic resection. Because of the risk of cancer development also in gastric mucosa outside the polyp, neighboring fragments of gastric mucosa should undergo microscopic investigations. This procedure allows for identification of patients who can benefit most from oncological endoscopic surveillance. If Helicobacter pylori(H. pylori) infection of the gastric mucosa is confirmed, treatment strategies should include eradication of bacteria, which may prevent progression of intestinal metaplasia. The efficacy of H. pylori eradication should be checked 3-6 mo later.

CYP24A1 inhibition facilitates the anti-tumor effect of vitamin D3 on colorectal cancer cells

AIM:The effects of vitamin D3 have been investigated on various tumors, including colorectal cancer (CRC). 25-hydroxyvitamin-D3-24-hydroxylase (CYP24A1), the enzyme that inactivates the active vitamin D3 metabolite 1,25-dihydroxyvitamin D3 (1,25-D3), is considered to be the main enzyme determining the biological halflife of 1,25-D3. During colorectal carcinogenesis, the expression and concentration of CYP24A1 increases significantly, suggesting that this phenomenon could be responsible for the proposed efficacy of 1,25-D3 in the treatment of CRC. The aim of this study was to investigate the anti-tumor effects of vitamin D3 on the human CRC cell line Caco-2 after inhibition of the cytochrome P450 component of CYP24A1 activity. METHODS:We examined the expression of CYP24A1 mRNA and the effects of 1,25-D3 on the cell line Caco-2 after inhibition of CYP24A1. Cell viability and proliferation were determined by means of sulforhodamine-B staining and bromodeoxyuridine incorporation, respectively, while cytotoxicity was estimated via the lactate dehydrogenase content of the cell culture supernatant. CYP24A1 expression was measured by realtime reverse transcription polymerase chain reaction. A number of tetralone compounds were synthesized to investigate their CP24A1 inhibitory activity. RESULTS:In response to 1,25-D3, CYP24A1 mRNA expression was enhanced significantly, in a time- and dose-dependent manner. Caco-2 cell viability and proliferation were not influenced by the administration of 1,25-D3 alone, but were markedly reduced by coadministration of 1,25-D3 and KD-35, a CYP24A1-inhibiting tetralone. Our data suggest that the mechanism of action of co-administered KD-35 and 1,25-D3 does not involve a direct cytotoxic effect, but rather the inhibition of cell proliferation. CONCLUSION:These findings demonstrate that the selective inhibition of CYP24A1 by compounds such as KD-35 may be a new approach for enhancement of the anti-tumor effect of 1,25-D3 on CRC.

Design and synthesis of novel triazole antifungal derivatives based on the active site of fungal lanosterol 14a-demethylase(CYP51)

一系列 1-(1H-1,2,4-triazole-1-yl )-2-(2,4-difluorophenyl)-3-(N-isoproyl-N-substituted-amino)-2-propanols 根据 lanosterol 14a-demethylase (CYP51 ) 的活跃地点被设计了并且综合。他们的结构被 MS 和 1 H NMR。在 vitro，这些综合混合物的抗真菌的活动与八人的病原的真菌被作比较。结果证明所有标题混合物对测试到某程度的真菌展出了活动。混合物 3c， 3d， 7a， 7b 和 7c 展出了更多的有势力对将近除了曲霉属菌 fumigatus，真菌比 fluconazole 测试了的所有的抗真菌的活动。

Electrochemical determination of vitamin C in the presence of uric acid by a novel TiO_2 nanoparticles modified carbon paste electrode

维生素 C (维生素酸或 AA ) 的电气化学的行为在与 TiO2 nanoparticles 和 2,2-(1,2 butanediylbis (nitriloethylidyne )) 修改的一个碳浆糊电极的表面上被调查 -bis-hydroquinone (BBNBH ) 。准备修改电极在 AA 的电气化学的氧化显示出一个有效催化角色，导致在氧化过电位和电极反应的动力学的改进的显著减少。这个修改电极为 AA 和尿酸(UA ) 展出分开得好的氧化山峰。修改电极成功地被申请在药品的准备的 AA 的精确决心。

An efficient and mild protocol for the synthesis of unsymmetrical ureas in the absence of catalyst and additives

A new practical method for the synthesis of unsymmetrical ureas was achieved by reaction of phenylurea with primary and secondary amines under neutral and mild condition in very good yields.The reaction took place in refluxing dioxane and does not require any catalyst or additives.

Synthesis and antitumor activity of 7-azaindirubin

二十 7-azaindirubin 衍生物被设计并且综合。他们的反肿瘤活动与 DU145 房间线在 vitro 被作比较。药理学结果证明大多数准备混合物显示了优秀活动。化合物 18 在测试混合物之中展出了大多数有势力反肿瘤活动。

Design, Synthesis and Biological Evaluation of 2-Aroyl-3-aryl-6,7-dihydro-5H-furo[3,2-g]chromen Derivatives as a Novel Series of Estrogen Receptor Modulators

Based on the principles of the bioisosterism, combination of the active substructures of selective estrogen receptor modulators which are currently therapeutic agents available for the prevention and treatment of various es-trogen dependent diseases, and structural optimization, a novel series of 2-aroyl-3-aryl-6,7-dihydro-5H-furo[3,2-g]-chromen derivatives was designed as potent selective estrogen receptor modulators via molecular docking. The target compounds have been synthesized, and characterized by IR, proton NMR, ESI-MS, elemental analysis and evaluated for their antitumor activity against human osteosarcoma U2OS-EGFP-4F12G cell line. Some target compounds showed good inhibition effects on U2OS-EGFP-4F12G cell line and the preliminary structure-activity relationships were discussed.

Synthesis of mangiferin derivates and study their potent PTP1B inhibitory activity

蛋白质酷氨酸磷酸酶 1B (PTP1B ) 为糖尿病 mellitus 作为一个潜在的处理从药工业收到了可观的注意。Mangiferin 被报导了拥有重要的反糖尿病患者活动。基于以前的学习，八新 mangiferin derivates 为他们的 PTP1B 禁止的活动被综合并且评估。他们中的一些在 PTP1B 上显示了好禁止的活动。

Highly Efficient and Recyclable Catalyst HBF_4·SiO_2 Catalyzed Synthesis of β-Enamino Compounds Under Solvent-free Conditions

Fluoroboric acid adsorbed on silica-gel(HBF4·SiO2) has been found to be an extremely efficient and recyclable catalyst for the preparation of β-enaminones and β-enamino esters under solvent-free conditions.

P_2O_5 mediated rapid condensation of 2-aminothiophenol with aromatic aldehydes at ambient temperature

在好收益形成的 2-Arylbenzothiazoles (65 鈥 ?0%) 由有用在周围的温度的 P2O5 的芳香的醛的 aminothiophenols 的冷凝作用。

Antiplasmodial,cytotoxic activities and characterization of a new naturally occurring quinone methide pentacyclic triterpenoid derivative isolated from Salacia leptoclada Tul.(Celastraceae)originated from Madagascar

Objective:To validate scientifically the traditional use of Salacia leptoclada Tul.(Celastraceae)(S.leptoclada)and to isolate and elucidate the structure of the biologically active compound.Methods:Bioassay-guided fractionation of the acetonic extract of the stem barks of S.leptoclada was carried out by a combination of chromatography technique and biological experiments in viro using Plasmodium falciparum and P388 leukemia cell lines as models.The structure of the biologically active pure compound was elucidated by 1D and 2D NMR spectroscopy and mass spectrometry.Results:Biological screening of S.leptoclada extracts resulted in the isolation of a pentacyclic triterpenic quinone methide.The pure compound exhibited both in vitro a cytotoxic effect on murine P388 leukemia cells with IC_(50)value of(0.041±0.020)μg/mL and an antiplasmodial activity against the chloroquine-resistant strain FC29 of Plasmodium falciparum with an IC_(50)value of(0.052±0.030)μg/mL.Despite this interesting anti-malarial property of the lead compound,the therapeutic index was weak(0.788).In the best of our knowledge,the quinone methide pentacyclic triterpenoid derivative compound is reported for the first time in S.leptoclada.Conclusions:The results suggest that furthers studies involving antineoplastic activity is needed for the development of this lead compound as anticancer drug.

Transferring CdTe Nanoparticles from Liquid Phase to Polyvinylpyrrolidone Nanofibers by Electrospinning and Detecting Its Photoluminescence Property

The major aim of this work was to synthesize thio-stabilized CdTe nanoparticles(NPs) in an aqueous solution,which was then enwrapped with cetyltrimethylammonium bromide(CTAB),and finally transferred to the polyvinylpyrrolidone(PVP) matrix by electrospinning. The PVP nanofibers containing CdTe NPs were characterized by scanning electron microscopy(SEM) and transmission electron microscopy(TEM),to observe the morphology of the nanofibers and the distribution of CdTe NPs. The selective area electronic diffraction(SAED) pattern verified that CdTe NPs were cubic lattice. The photoluminescence(PL) spectrum indicated that CdTe NPs existed in an optical style in PVP nanofibers. Moreover,X-ray photoelectron spectra(XPS) revealed that thiol-stabilized CdTe NPs were enwrapped by CTAB,and PVP acted as a dispersant in the process of electrospinning.

Brand-new Function of Well-designed Ionic Liquid: Inhibitor of Tumor Cell Growth

An investigation into the effect of several novel well-designed guanidinium salt ionic liquids(GILs) on inhibitting tumor growth is described. The GILs which have longer alkyl chain(6―18 carbon atoms) exhibit the high cytotoxicity to Hela299, B16 and SMMC-7721 cells so as to inhibit their proliferation. The inhibitory effect of the most effective GIL12 is about 10-fold higher than that of MMC(a common chemotherapy drug in clinic).