以聚乙二醇-b-聚四乙烯基吡啶为模板制备聚联苯胺微/纳米颗粒及其电容特性

以两亲性嵌段共聚物聚乙二醇-b-聚四乙烯基吡啶(PEO-b-P4VP)为模板制备聚联苯胺微/纳米颗粒,调节模板剂胶束溶液pH,得到了一系列形貌和尺寸可控的聚联苯胺微/纳米颗粒。利用红外光谱、核磁共振、透射电镜、循环伏安、恒电流放电、交流阻抗等测试对材料的结构和性能进行了表征。模板法合成的聚联苯胺为平均直径小于200nm的亚微米至纳米级棒状颗粒,其直径随着模板剂胶束溶液pH的降低而增加。所得聚联苯胺颗粒均显示了一定的电化学活性,当电流密度为1A/g时,聚联苯胺的比电容量达到306.3F/g,经过长时间的充放电测试,不同条件下合成的聚联苯胺的容量衰减率均很小,表现出良好的循环稳定性且各样品电化学性能呈现出随着直径的减小而增强的趋势。     

Stability indicating RP-HPLC method development and validation for oseltamivir API

The present study describes the development and subsequent validation of a stability indicating reverse-phase HPLC (RP-HPLC) method for the analysis of oseltamivir active pharmaceutical ingredient (API). The proposed RP-HPLC method utilizes Kromasil C(18), 5 microm, 250 mm x 4.6 mm i.d. column (at ambient temperature), gradient run (using acetonitrile and triethylamine as mobile phase), effluent flow rate (1.0 ml/min), and UV detection at 215 nm for analysis of oseltamivir. The described method was linear over the range of 70-130 microg/ml (r(2)=0.999). The precision, ruggedness and robustness values were also within the prescribed limits (<1% for system precision and <2% for other parameters). Oseltamivir was exposed to acidic, basic, oxidative and thermal stress conditions, and the stressed samples were analyzed by the proposed method. Chromatographic peak purity results indicated the absence of co-eluting peaks with the main peak of oseltamivir, which demonstrated the specificity of assay method for estimation of oseltamivir in presence of degradation products. The proposed method can be used for routine analysis of oseltamivir in quality control laboratories.     

Discovery,Development, and Patent Trends on Molnupiravir: A Prospective Oral Treatment for COVID-19

The COVID-19 pandemic needs no introduction at present. Only a few treatments are available for this disease, including remdesivir and favipiravir. Accordingly, the pharmaceutical industry is striving to develop new treatments for COVID-19. Molnupiravir, an orally active RdRp inhibitor, is in a phase 3 clinical trial against COVID-19. The objective of this review article is to enlighten the researchers working on COVID-19 about the discovery, recent developments, and patents related to molnupiravir. Molnupiravir was originally developed for the treatment of influenza at Emory University, USA. However, this drug has also demonstrated activity against a variety of viruses, including SARS-CoV-2. Now it is being jointly developed by Emory University, Ridgeback Biotherapeutics, and Merck to treat COVID-19. The published clinical data indicate a good safety profile, tolerability, and oral bioavailability of molnupiravir in humans. The patient-compliant oral dosage form of molnupiravir may hit the market in the first or second quarter of 2022. The patent data of molnupiravir revealed its granted compound patent and process-related patent applications. We also anticipate patent filing related to oral dosage forms, inhalers, and a combination of molnupiravir with marketed drugs like remdesivir, favipiravir, and baricitinib. The current pandemic demands a patient compliant, safe, tolerable, and orally effective COVID-19 treatment. The authors believe that molnupiravir meets these requirements and is a breakthrough COVID-19 treatment.     

Nigella sativa L. and COVID-19: A Glance at The Anti-COVID-19 Chemical Constituents,Clinical Trials,Inventions, and Patent Literature

COVID-19 has had an impact on human quality of life and economics. Scientists have been identifying remedies for its prevention and treatment from all possible sources, including plants. Nigella sativa L. (NS) is an important medicinal plant of Islamic value. This review highlights the anti-COVID-19 potential, clinical trials, inventions, and patent literature related to NS and its major chemical constituents, like thymoquinone. The literature was collected from different databases, including Pubmed, Espacenet, and Patentscope. The literature supports the efficacy of NS, NS oil (NSO), and its chemical constituents against COVID-19. The clinical data imply that NS and NSO can prevent and treat COVID-19 patients with a faster recovery rate. Several inventions comprising NS and NSO have been claimed in patent applications to prevent/treat COVID-19. The patent literature cites NS as an immunomodulator, antioxidant, anti-inflammatory, a source of anti-SARS-CoV-2 compounds, and a plant having protective effects on the lungs. The available facts indicate that NS, NSO, and its various compositions have all the attributes to be used as a promising remedy to prevent, manage, and treat COVID-19 among high-risk people as well as for the therapy of COVID-19 patients of all age groups as a monotherapy or a combination therapy. Many compositions of NS in combination with countless medicinal herbs and medicines are still unexplored. Accordingly, the authors foresee a bright scope in developing NS-based anti-COVID-19 composition for clinical use in the future.     

维吾尔语句子边界识别算法的设计与实现

本文分析维吾尔语的句子结束形式,研究维吾尔语句子边界规则,给出了句子划分思路,并实现了维吾尔语句子边界识别算法及程序.在对大量手工划分句子语料进行统计测试结果表明,该句子边界识别程序准确率超过98.7%.维吾尔语句子边界识别的研究对实现维吾尔语词性标注系统、维吾尔语句法分析器、机器翻译等众多领域有着很高的实际意义.     

Preparation of polybenzidine submicrorods with controllable morphology using poly (ethylene oxide)-b-polystyrene as a template and its electrochemical properties

Polybenzidine (PBz) particles were formed by the chemical polymerization in micelles of block copolymer by using Poly (ethylene oxide)-b-Polystyrene [PEO₁₁₃-b-PS_x (x = 50, 58 and 100)] as templates. The samples were characterized by IR, UV-vis absorption spectroscopy, transmission electron microscopy, cyclic voltammetry, constant current charge-discharge and electrochemical impedance to determine their morphologies and electrochemical properties. The results show that the prepared PBz is submicron to nanometer rod-like conducting particles with uniform sizes. Removing the templates did not affect the morphology but slightly reduced the size of the PBz particles. The size and morphology of PBz particles can be tuned by adjusting the amount of monomer. The PBz submicrorods showed 412 F·g^?1 specific capacitance in 0.3 mol·L^?1HClO₄ at the current density of 1 A·g^?1, indicating its better electrochemical activity. The specific capacitance of the PBz particles reduced less than 10% after 500 charge-discharge cycles at the current density of 3 A·g^?1, indicating its good cycling stability.     

Molecular Interactions in Formamide + Isomeric Butanols: An Ultrasonic and Volumetric Study

Densities, , ultrasonic speeds, u and viscosities, of the binary mixtures of formamide (FA) with 1-butanol, 2-methyl-1-propanol, and 2-methyl-2-propanol, including those of pure liquids, were measured over the whole composition range at 35°C. Using the experimental values of , u and , the deviations in isentropic compressibility, _s , excess volume, V ^E, viscosity, , and excess Gibbs energy of activation of viscous flow, G* ^E , were calculated from the linear dependence of these parameters on composition of mixtures. The apparent molar isentropic compressibility, K _,2 and apparent molar volume, V ^,2 of alcohols in FA were also calculated. The variations of these parameters with composition are discussed from the point of view of intermolecular interactions in these mixtures. The V ^E data have also been analyzed using Prigogine–Flory–Patterson theory. An analysis of each of the three contributions, viz., interactional, free volume, and P* effect to V ^E shows that P*, the internal pressure parameter of the theory, plays a dominant role in deciding the sign and magnitude of V ^E.     

Parahalogenated phenols accelerate the photochemical release of nitrogen oxides from frozen solutions containing nitrate

The photolysis of nitrate anion (NO(3)(-)) contained in surface ice and snow can be a regionally significant source of gas-phase nitrogen oxides and affect the composition of the planetary boundary layer. In this study, the photochemical release of nitrogen oxides from frozen solutions containing NO(3)(-) in the presence of organic compounds was investigated. Gas-phase nitrogen oxides were quantified primarily by NO-O(3) chemiluminescence detection of NO and NO(y) (=NO + NO(2) + HONO + HNO(3) + ∑PAN + ∑AN ...) and cavity ring-down spectroscopy of NO(2) and total alkyl nitrates (∑AN). The photochemical production of gas-phase NO(y) was suppressed by the presence of formate, methanesulfonate, toluene, or phenol. In contrast, para-halogenated phenols (in the order of Cl > Br > F) promoted the conversion of NO(3)(-) to gas-phase NO(y), rationalized by acidification of the ice surface.     

A review on catalytic role of heterogeneous acidic catalysts during glycerol acetylation to yield acetins

Glycerol is a colorless, odorless, and non-toxic compound and has application in food, paint, and pharmaceutical industries. At an industrial scale, glycerol (GL) commonly forms as a by-product of soap and biodiesel producing industries. To utilize the excess GL of biodiesel industry, former has been employed as a building block to manufacture value added products such as acetins by fine chemical manufacturers. Acetins, including monoacertin (MA), diacetin (DA) and triacetin (TA), has diverse application such as in cosmetics, fuel additives, pharmaceuticals, leather, and food processing. Specifically, TA is employed as an additive to improve the anti-knocking property of gasoline and viscosity and cold flow properties of biofuel. The acetins are frequently produced at an industrial scale via a homogeneous Brønsted acid catalysed process employing acetic acid or acetic anhydride as an acetylating agent. Homogeneous acid catalysts are corrosive, non-reusable, difficult to separate from the reaction mixture, and sensitive to water, which is formed as a by-product during the glycerol acetylation. To address the issues, Brønsted or Lewis acidic group have been immobilized over various matrices (e.g., mixed metal oxides, mesoporous silica, ion exchange resins, carbon, zeolites, and magnetic nanoparticles) to prepare the heterogeneous acidic catalysts for the glycerol acetylation. Both the sites assisted the carbocation mediated esterification of glycerol with acetic acid or acetic anhydride. The ease of catalyst separation from the reaction mixture and reusability are the major advantages of their usage. However, lower conversion levels with low product selectivity, catalysts deactivation, and partial dissolution in the reaction mixture are the concerns related to the catalysts. To address these issues, novel catalyst preparation techniques to incorporate the variety of active sites over the matrix surface have been employed in the literature, which will be highlighted in detail in the present review article.