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621.
An electrochemical protocol based on reduction is developed to determine methylprednisolone using single-wall carbon nanotubes (SWNTs) modified edge plane pyrolytic graphite electrode (EPPGE). To obtain a good sensitivity, instrumental variables were studied using Square Wave Voltammetry (SWV). The voltammetric results indicate that SWNTs modified EPPGE remarkably enhances the reduction of methylprednisolone which leads to considerable improvement of peak current with shift of peak potential to less negative values. The voltammetric current showed a linear response for methylprednisolone concentration in the range 5-500 nM with a sensitivity of 98 nA nM−1. The limit of detection was estimated to be 4.5 × 10−9 M. The developed method is used for the determination of methylprednisolone in pharmaceutical dosages and human blood plasma samples of patients undergoing treatment with methylprednisolone. The major metabolites present in blood plasma did not interfere with the present investigation as they did not exhibit reduction peak in the experimental range used. A comparison of results with high performance liquid chromatography (HPLC) indicates a good agreement. 相似文献
622.
Diabetes mellitus (DM) is the most prevalent non‐contagious disease, which has affected a large number of people all over the world. Among all treatments known to have a positive influence in the control of DM, insulin therapy is the most common and effective one. Nowadays, various methods of insulin delivery are under investigation, which are able to reach a plausible bioavailability with ignorable side effects instead of insulin injection. This article presents a comprehensive review of the insulin therapy approach with a focus on modified methods in insulin delivery strategies and current advances in engineered insulin delivery systems. 相似文献
623.
Rakesh Chilivery Gousia Begum Vahinipathi Chaitanya Rohit Kumar Rana 《Angewandte Chemie (International ed. in English)》2020,59(21):8160-8165
A bio‐inspired method is used to render controlled wrinkling surface patterns on supramolecular architectures assembled from polyoxometalate (POM) clusters. It involves a polyamine‐multivalent anion interaction generating positively charged coacervates, which while dictating the assembly of POM into spherical structures further facilitate an interesting surface morphogenesis with wrinkling patterns. This spontaneous surface wrinkling depends on the type of multivalent anion and the pH. As the polyamine‐anion interaction becomes stronger, the wrinkles turn denser with lesser depth, which eventually undergoes post‐buckling to engender a complex surface pattern. Interestingly, the order of influence exerted by different anions on the morphology follows the Hofmeister series. Moreover, the mild synthesis conditions keep the functional POM units dispersed in the sphere with a structural transformability to their lacunary form. 相似文献
624.
Fereshteh Oustadi Rana Imani Masoumeh Haghbin Nazarpak Ali Mohammad Sharifi 《先进技术聚合物》2020,31(8):1783-1792
Nowadays, despite remarkable progress in developing bone tissue engineering products, the fabrication of an ideal scaffold that could meet the main criteria, such as providing mechanical properties and suitable biostability as well as mimicking the bone extracellular matrix, still seems challenging. In this regard, utilizing combinatorial approaches seems more beneficial. Here, we aim to reinforce the mechanical characteristics of gelatin hydrogel via a combination of Genipin‐based chemical cross‐linking and incorporation of the poly l ‐lactic acid (PLLA) nanocylinders for application as bone scaffolds. Amine‐functionalized nanocylinders are prepared via the aminolysis procedure and incorporated in gelatin hydrogel. The nanocylinder content (0, 1, 2, 3, and 4 wt%) and cross‐linking density (0.1, 0.5, and 1 wt/vol%) are optimized to achieve suitable morphology, swelling ratio, degradation rate, and mechanical behaviors. The results indicate that hydrogel scaffold cross‐linking by 0.5 wt% of Genipin shows optimized morphological feathers with a pore size of around 300 to 500 μm as well as an average degradation rate (40.09% ± 3.08%) during 32 days. Besides, the incorporation of 3 wt% PLLA nanocylinders into the cross‐linked gelatin scaffold provides an optimized mechanical reinforcement as compressive modulus, and compressive strength show a 4‐ and 2.6‐fold increase, respectively. 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide assay indicates that the scaffold does not have any cytotoxicity effect. In conclusion, gelatin composite reinforced with 3 wt% PLLA nanocylinders cross‐linked via 0.5 wt/vol% Genipin is suggested as a potential scaffold for bone tissue engineering applications. 相似文献
625.
Askoxylakis V Zitzmann-Kolbe S Zoller F Altmann A Markert A Rana S Marr A Mier W Debus J Haberkorn U 《Molecules (Basel, Switzerland)》2011,16(2):1559-1578
The transfer of peptides identified through the phage display technology to clinical applications is difficult. Major drawbacks are the metabolic degradation and label instability. The aim of our work is the optimization of DUP-1, a peptide which was identified by phage display to specifically target human prostate carcinoma. To investigate the influence of chelate conjugation, DOTA was coupled to DUP-1 and labeling was performed with 111In. To improve serum stability cyclization of DUP-1 and targeted D-amino acid substitution were carried out. Alanine scanning was performed for identification of the binding site and based on the results peptide fragments were chemically synthesized. The properties of modified ligands were investigated in in vitro binding and competition assays. In vivo biodistribution studies were carried out in mice, carrying human prostate tumors subcutaneously. DOTA conjugation resulted in different cellular binding kinetics, rapid in vivo renal clearance and increased tumor-to-organ ratios. Cyclization and D-amino acid substitution increased the metabolic stability but led to binding affinity decrease. Fragment investigation indicated that the sequence NRAQDY might be significant for target-binding. Our results demonstrate challenges in optimizing peptides, identified through phage display libraries, and show that careful investigation of modified derivatives is necessary in order to improve their characteristics. 相似文献
626.
627.
B. K. Rana A. K. Shukla R. Topno R. M. Tripathi V. D. Puranik 《Journal of Radioanalytical and Nuclear Chemistry》2010,285(3):505-510
The study summarizes radiological characteristics of Banduhurang open cast mine which includes qualitative and quantitative behavior of 222Rn concentration, external gamma radiation level over the mine pit as well as in its adjoining environment, long-lived alpha (LLα) activity concentration associated with the respirable size of ore dust and assessment of dose to the mine workers in 2006–2008. The investigations reveal that geometric means (χg) of measured radon concentration were 36.39, 38.69, 26.64 and 24 Bq m?3 with respective geometric standard deviations (σg) were 1.52, 1.55, 1.36 and 1.68 Bq m?3 and χg of gamma absorbed dose rates were 0.54, 0.64, 0. 45 and 0.15 μGy h?1 with respective σg were 1.63, 1.53, 1.52 and 1.72 μGy h?1 over the mine pit, ore yard, waste yard and in the surrounding environment within a 10 km radius to the mine, respectively. The χg of LLα activity was observed to be 16 mBq m?3 with σg of 1.9 mBq m?3. The annual mean effective dose equivalent received by the member radiation workers of Banduhurang mine was estimated to 1.41 mSv y?1, which is about 7% of the prescribed dose limits of 20 mSv y?1. 相似文献
628.
R. Acharya K. K. Swain A. D. Shinde N. S. Bhamra K. Chakrabarty C. G. Karhadkar Tej Singh Y. S. Rana P. K. Pujari D. K. Shukla A. V. R. Reddy 《Journal of Radioanalytical and Nuclear Chemistry》2014,302(3):1525-1530
The pneumatic carrier facility (PCF) of Dhruva reactor is being extensively used for neutron activation analysis (NAA) studies pertaining to research work as well as routine sample analysis. It is useful for the determination of trace elements using short and medium half-lives radioisotopes produced in neutron activation with available higher neutron flux (~5 × 1013 cm?1 s?1). Solid samples placed in high density polypropylene capsule, are irradiated for 1 min duration and radioactive assay is carried out by high resolution gamma ray spectrometry. Design aspects of PCF and various applications to samples of diverse matrices using NAA are presented. 相似文献
629.
Shalika Rana Kiran Rawat Madhavi Mahendru Yogendra Padwad Yogesh B. Pakade Brij Lal 《Natural product research》2015,29(23):2242-2246
Clematis gouriana (Ranunculaceae), a perennial herb, is used by the local inhabitants of the western Himalayan region for its medicinal properties. Major bioconstituents of C. gouriana leaves using different solvent extracts were obtained and analysed. The results revealed promising contents of phenolics (from 18.19 ± 0.10 to 22.17 ± 0.10 mg g? 1) as gallic acid and flavonoids (from 2.83 ± 0.01 to 6.52 ± 0.08 mg g? 1) as quercetin equivalent in different extracts. Aqueous acetone extract showed higher antioxidant activity with IC50 value of 129.11 and 25.35 μg mL? 1 against DPPH and ABTS free radicals, respectively. Antioxidant yield ranged from 16.87 ± 0.27 to 24.48 ± 0.13 mg g? 1 of Trolox equivalent in different extracts as measured by the FRAP assay. Furthermore, ethylacetate extract exhibited strong in vitro cytotoxicity against Chinese hamster ovary and glioma cell lines. Proximate composition (proteins, fats, ash and minerals) of C. gouriana leaves was also assessed. Results demonstrated the potential of C. gouriana bioconstituents as nutraceuticals. 相似文献
630.
β‐Octamethoxy‐Substituted 22π and 26π Stretched Porphycenes: Synthesis,Characterization, Photodynamics,and Nonlinear Optical Studies 下载免费PDF全文
Anup Rana Sangsu Lee Prof. Dr. Dongho Kim Dr. Pradeepta K. Panda 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(34):12129-12135
Three meso‐expanded tetrapyrrolic aromatic macrocycles, including 22π and 26π acetylene–cumulene bridged stretched octamethoxyporphycenes and octamethoxy[22]porphyrin‐(2.2.2.2), are reported, for the first time, by modification of previously reported synthetic methods. This strategy led to an enhancement in the overall yield of their corresponding octaethyl analogues. The methoxy‐substituted expanded porphycenes display slightly blueshifted absorption relative to their ethyl analogues, along with very weak fluorescence, probably due to efficient intramolecular charge transfer (ICT). Additionally, the two‐photon absorption (TPA) cross sections of these macrocycles were evaluated; these are strongly related to core expansion of the porphyrin aromaticity through increased meso‐bridging carbon atoms as well as conformational flexibility and substitution effects at the macrocyclic periphery. In particular, the octamethoxy stretched porphycenes display strong TPA compared with the octaethyl analogues due to the dominant ICT character of methoxy groups with a maximum TPA cross section of 830 GM at 1700 nm observed for 26π‐octamethoxyacetylene–cumuleneporphycene. 相似文献