Synthesis,characterisation and potential applications of polyaniline/chitosan‐Ag‐nano‐biocomposite

Biodegradable polymers have greatly promoted the development of environmental, biomedical and allied sciences because of their biocompatibility and doping chemistry. The emergence of nanotechnology has envisaged greater options for the development of biodegradable materials. Polyaniline grafted chitosan (i.e. biodegradable PANI) copolymer was prepared by the chemical in situ polymerisation of aniline using ammonium per sulphate as initiator while Ag nanoparticle were synthesised by chemical reduction method and incorporated in to the polymer matrix. The as prepared materials were characterised by X‐ray diffraction, Fourier transform Infra‐red spectroscopy, transmission electron microscopy, energy dispersive X‐ray analysis. Moreover energy storage capacity, impedance properties were also studied. The main focus was on the photocatalytic degradation of organic dyes to remove the toxic and carcinogenic pollutants. This polymer nano‐biocomposite has multifold applications and can be used as excellent materials for enhanced photodegradation and removal of toxic contaminants from waste waters and natural water streams. In addition, the biocompatible materials with excellent mechanical properties and low toxicity can also be used for tissue engineering, drug delivery and electrical energy storage devices.Inspec keywords: silver, filled polymers, polymer blends, nanocomposites, nanoparticles, nanofabrication, biodegradable materials, polymerisation, reduction (chemical), Fourier transform infrared spectra, transmission electron microscopy, X‐ray chemical analysis, X‐ray diffractionOther keywords: polyaniline‐chitosan‐silver‐nanobiocomposite, biodegradable polymers, biocompatibility, doping chemistry, nanotechnology, biodegradable PANI, polyaniline grafted chitosan copolymer, biodegradable materials, chemical in situ polymerisation, nanoparticle, polymer matrix, chemical reduction method, Fourier transform Infrared spectroscopy, transmission electron microscopy, energy dispersive X‐ray analysis, X‐ray diffraction, energy storage capacity, impedance properties, carcinogenic pollutants, toxic pollutants, photodegradation, toxic contaminants, natural water streams, waste waters, drug delivery, tissue engineering, electrical energy storage devices, mechanical properties, Ag     

Extraction of admittance parameters of symmetrically doped AlGaN/GaN/AlGaN DH-HEMT for microwave frequency applications

Microsystem Technologies - An analytical model for determining intrinsic short-circuit admittance (Y) parameters of AlGaN/GaN/AlGaN Double Heterostructure (DH) High Electron Mobility Transistor...     

Synthesis and polymerization of a new iodine‐containing monomer

A new iodine‐containing methacrylate monomer, 3,4,5‐triiodobenzoyloxyethyl methacrylate (TIBEM), was synthesized by coupling 2‐hydroxyethyl methacrylate (HEMA) with 3,4,5‐triiodobenzoic acid. The monomer was characterized by ¹H nuclear magnetic resonance, infrared (IR), and ultraviolet spectra. Homopolymerization and copolymerization of the monomer with methyl methacrylate (MMA) were carried out using 2,2′‐azobis isobutyronitrile as the initiator. A terpolymer of TIBEM, MMA, and HEMA was also synthesized. The copolymers were characterized by IR, gel permeation chromatography, differential thermal analysis, and thermogravimetric analysis (TGA). High molecular weight polymers were produced with MMA at different feed compositions of TIBEM. The polymers were found to be freely soluble in common solvents for acrylic polymers. TGA showed little decomposition of the copolymer below 280°C. Copolymers showed good radiopacity at 25 wt % of TIBEM in the feed. These copolymers could find applications in medical and dental areas where radiopacity is a desirable feature of the implants. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2580–2584, 2003     

Fabrication and Characterization of Matrix-Type Transdermal Patches Loaded with Ramipril and Repaglinide Through Cellulose-based Hydrophilic and Hydrophobic Polymers: In Vitro and Ex Vivo Permeation Studies

Transdermal patches loaded with ramipril and repaglinide were prepared with the ambition to develop matrix-type transdermal drug delivery system for enhanced permeability and hence improved bioavailability. Different formulations were designed by intermittent concentrations of hydroxypropyl methylcellulose K4M as hydrophilic polymer and ethyl cellulose as hydrophobic polymer. Solvent casting method was used for the fabrication of transdermal patches. Oleic acid and propylene glycol were used to enhance permeability along with polyethylene glycol 400 as plasticizer. Newly designed patches were then evaluated for various physicochemical and mechanical properties. Compatibility studies were performed by Fourier transformed infrared spectroscopy which did not reveal any interaction between drug and polymers. Crystalline nature of drugs was confirmed when they were subjected to X-ray diffraction study and surface morphological studies using scanning electron microscopy. Transdermal patches were of good mechanical strength with folding endurance of more than 300-fold and 100% flatness. Percent drug contents of ramipril and repaglinide ranged from 90 to 105%, i.e., analogous to official limits. In vitro and ex vivo permeation studies were executed using franz diffusion cell. The cumulative amount of drug permeated through skin was 55.22–112.72% for repaglinide and 73.14–91.46% for ramipril. The release behavior of the permeated drug was analyzed by the application of model-dependent approaches. The results showed that Korsmeyer–Peppas model was found to be dominating in most of the formulations and drugs followed diffusion mechanism. It could be concluded that hydroxypropyl methylcellulose K4M and ethyl cellulose has great potential for ramipril and repaglinide as a vector for transdermal drug delivery effectively because of the formation of smooth surfaces of patches, high folding endurance, and entrapment efficiency with the ability to release the drugs in sustained manner.     

Double gene targeting PCR assay for the detection of Crocodylus porosus in commercial products

The demand for crocodile meat is quickly growing because of its exotic and organoleptic appeal and also the low content of cholesterol and lipids. Moreover, crocodile oil and blood have been used in alternative medicines for treating asthma and several other ailments since ancient times. Furthermore, crocodile hides have great demand in leather industries. All of these have collectively contributed to the extensive hunting, illegal trading and consequent decline of crocodiles in most parts of the world. To keep space with the growing demands, some crocodile species such as Crocodylus porosus have been raised in farms and its commercial trades have been legalised. However, demand for wild crocodiles in foods and medicines has continued in high gear. Recently, several DNA-based methods have been proposed for crocodile detection, but those assays are based on single gene and longer-sized amplicon targets that break down during extensive processing. To address this gap, here we developed and validated a highly stable double gene targeted multiplex PCR assay for the identification of C. porosus materials in commercial products. The assay involved two short sites from C. porosus atp6 (77 bp) and cytb (127 bp) genes and a universal internal control (99 bp) for eukaryotes. The PCR primers were cross-tested against 18 species and validated under pure and mixed matrices under extensive boiling, autoclaving and microwave cooking conditions. Finally, it was used to identify five crocodile-based commercial products. The lower limits of detection for atp6 and cytb genes were 0.001 ng and 0.01 ng DNA, respectively, in pure meat and 1% under mixed matrices. Some inherent features, such as 77–127 bp amplicon sizes, exceptional stability and superior sensitivity, suggested the assay could be used for the identification of C. porosus in any forensic specimen.     

Efficient rule mining and compression for RDF style KB based on Horn rules

The volume of published linked open datasets in RDF format is growing exponentially in the last decades. With this continuous proliferation of this growth, demands for managing, accessing, and compressing the RDF dataset have become increasingly important. Most approaches are focused on the structured compression technique while a very few researches have been done for compact representation of the RDF dataset. In this paper, we have proposed an efficient rule mining and compression approach for RDF datasets through various meaningful semantic association rules determined from the RDF graph. We have introduced grammar-based pattern system, clustering of rules, rules pruning, and Top-k scheme to improve the expressiveness of rule patterns, identify the similarity within the random pair of rules, extract the most delicate rules, find the accurate mining threshold, and efficiently learn the rules during the rule mining process from RDF Knowledge Base. Our proposed system uses Horn rules to achieve better compression through storing the triples matched with the precedent part while deleting the triples matched with the head part of the rules. For decreasing the mining time, we have introduced the ranking of the rules. The experimental result on the benchmark dataset asserts that our proposed rule mining and compression scheme has achieved approximately 22.10%, 40.5%, and 44% better compression than the exiting AMIE+, Rule-based compression, and TripleBit approaches, respectively. Our system also has achieved better performance both in terms of compression time and rule mining cost.

     

Human AKR1C Isoforms Oxidize the Potent Proximate Carcinogen 7,12-DMBA-3,4-diol in the Human Lung A549 Carcinoma Cell Line

Aldo-keto reductases (AKRs) oxidize structurally diverse PAH trans -dihydrodiols to yield reactive and redox active o -quinones. This study examined the ability of AKR1C2 and AKR1C4 to oxidize PAH trans -dihydrodiols of the benz[ a ]anthracene series. The enzymes oxidized 100% of the racemic trans -dihydrodiols and the highest utilization ratios were observed for the more potent proximate carcinogens 7,12-dimethylbenz[ a ]anthracene-3,4-diol (DMBA-3,4-diol) and 7-methylbenz[ a ]anthracene-3,4-diol (7-MBA-3,4-diol). Human multiple tissue expression array analysis revealed high expression of AKR1C isoforms in the human lung carcinoma cell line A549. Both Western blot analysis using AKR1C9 antisera and enzymatic assays using 1-acenapthanol as substrate confirmed the presence of active AKR1C enzymes in A549 cells. To determine the importance of AKR1C-mediated trans -dihydrodiol oxidation in A549 cells, DMBA-3,4-diol was incubated with cell lysates in the presence of 2-mercaptoethanol. Liquid chromatography/mass spectrometric analysis identified peaks that corresponded to the synthetically prepared mono- and bis -thioether conjugates of DMBA-3,4-dione confirming the ability of these cells to oxidize DMBA-3,4-diol to the corresponding o -quinone. Together, these studies demonstrate the importance of human AKR1Cs in PAH activation and their possible role in lung cancer.     

喜来芝石中提取的腐植酸与阿司匹林的分子络合物及其表征

阿司匹林具有退热、消炎、止痛和抗血小板凝集的作用。乙酰水杨酸分子含一个羧基和一个酯基。酯基容易被水解,导致其药效降低,并会对人体产生副作用。本研究的目的是用冻干技术和溶剂挥发技术,以原料的物质的量比为1∶1和1∶2,制备阿司匹林和腐植酸固态络合物。阿司匹林和腐植酸分子间相互作用通过差示扫描量热法(DSC)、X射线衍射(XRD)、傅里叶变换红外光谱学法(FT-IR)和扫描电子显微镜法(SEM)进行研究。用这些技术能清晰表明固态包合络合物的结构。对物质的量比为1∶2冻干络合物研究表明,阿司匹林的稳定性和溶出率显著提高。优选的冻干阿司匹林与腐植酸(1∶2)络合物对抑制鼠爪水肿和抗溃疡作用测得的最低值(0.63±0.10)与单纯的阿司匹林相比,有明显的降低,证明用其治疗具有非常显著的抗炎作用(P0.05)。