Search

Over Speed is one of the main reasons for increase in the occurrence of accidents nowadays. Many techniques are being used for over speed monitoring. However, these methods require lot of man power. In this paper, we present the design and implementation of a system, which provides a simple way to traffic authorities for monitoring of all the vehicles from the control room itself. This system calculates the speed and GPS coordinates continuously and these GPS coordinates help to find out the area in which the vehicle has been present and the maximum speed allowed in the respective area. The speed and the coordinates of vehicle calculated are continuously stored in a memory card. If the speed of any vehicle exceeds the speed limit, the driver is alerted through a buzzer indicating the same. If the driver still does not drive within the speed limit, an SMS, which contains the vehicle registration number, GPS coordinates at where he exceeded the speed limit, is sent to traffic authorities. Accordingly an over speed ticket can be issued against the same vehicle.

Asymmetric membranes for organic solvent nanofiltration (OSN) were fabricated from polyimides (PI) synthesised by polycondensation reactions. The effect of molecular weight and chemical structure of the synthesised PIs on the PI OSN membrane formation and performance was investigated. This work is the final part of a three parts study seeking a better understanding of how membrane formation parameters affect membrane performance. During a co-polymerisation reaction 3,3′,4,4′-benzophenone tetracarboxylic dianhydride was reacted with various diisocyanates i.e. toluene-2,4-diisocyanate, 4,4′-methylenebis(phenyl isocyanate), 3,3′-dimethoxy-4,4′-biphenyl diisocyanate, and isophorone diisocyanate. It has been shown that the rejection of PI OSN membranes is not influenced by the molecular weight of the PI which varied between 30,000 and 70,000 Da. However, there is a minimum molecular weight (35,000 Da) required to cast defect free membranes with good mechanical strength for OSN applications. Likewise, too high PI molecular weight (80,000 Da) results in too viscous dope solution which hinders membrane casting. Structural changes in the PI and the method of polymerisation (block vs random) were found to affect both flux and rejection of the membranes. The use of the random PI resulted in the formation of more open membranes having lower rejection and higher flux.

Heat shock proteins serve as important antigens in defense against infectious diseases. Members of HSP70 family, particularly microbial HSP70s have acquired special significance in immunity. In the present study, we evaluated the immunogenicity and protective efficacy of HSP70 of Salmonella enterica serovar Typhi against lethal infection by Salmonella in mice with or without adjuvants. The HSP70 gene was cloned and expressed in Escherichia coli BL21 and purified by affinity chromatography. Immunization of mice with HSP70 either alone or in combination with complete Freund's adjuvant (CFA) resulted in a significant increase in antibody titers as compared to control. Antibody isotyping revealed that HSP70 immunization induces both IgG1 and IgG2a antibodies to a significant extent but a higher IgG1/IgG2a ratio indicates a predominant Th2 response. There was a significant increase in lymphocyte proliferation, and levels of both Th2 and Th1 cytokines in cells isolated from immunized mice as compared to control. Immunization of mice with recombinant HSP70 either alone or in combination with CFA conferred 70-90% protection against lethal infections by Salmonella Typhi Ty2 or Salmonella Typhimurium. However, passive immunization with anti-HSP70 sera induced only partial protection in the immunized mice.

Aims: Chromium (III) is an insulinomimetic agent whose biological and/or environmental availability is frequently in the form of Cr(VI), which is known to be toxic. Wall-less mutant of Neurospora crassa (FGSC stock no. 4761) is known to possess insulin receptor in its cell membrane and hence is a good model for Cr toxicity studies. This study explores the toxicity of Cr(VI) and the possible consequences on simultaneous exposure to insulin in N. crassa. Methods and Results: Comet assay of N. crassa cells treated with 100 μmol l−1 Cr(VI) showed up to 50% reduction in comet tail lengths when incubated simultaneously with 0·4 U insulin. Fluorescence measurement in Cr(VI)-treated cells using DCFH-DA showed six- to eightfold increase in free radical generation, which was reduced to fourfold by 0·4 U insulin. Annexin-V/PI Flow cytometry analysis indicated necrotic cell death up to 28·7 ± 3·6% and 68·6 ± 2·5% on Cr(VI) exposure at concentrations 100 and 500 μmol l−1 which was reduced by 68·3 ± 3·2% and 48·9 ± 3·6%, respectively, upon addition of insulin. Conclusion: Insulin-mediated protection from DNA damage by Cr(VI) is because of scavenging of free radicals liberated during exposure to Cr(VI). Significance and Impact of the Study: Overall, Cr(VI) toxicity depends upon available insulin, indicating that Cr(VI) toxicity may be a serious issue in insulin-deficient individuals with diabetes.

The present study evaluates the toxicity from sub-chronic administration of CoCl(2) (12.5mg cobalt kg(-1) BW for 7 days) to male Sprague-Dawley rats in view of the beneficial effects of CoCl(2) in animals and for developing efficacious therapeutic regimen in humans. 32 rats weighing 200+/-25 g were used for all experiments. Blood was collected for hematological and biochemical analysis and various organs were dissected after perfusion of animals under anesthesia for other analyses. Mean feed consumption and feed conversion efficiency values were comparable across all study groups; however, hematological analysis depicted a significant increase in hemoglobin, hematocrit and RBC in the entire cobalt-supplemented groups, which are a component of its beneficial effect. There was a significant increase in monocytes, granulocytes and WBC after 1 and 24h, which were comparable with control after 7 days. Other biochemical analyses also showed no change with respect to control. Though the metal content increased significantly in liver initially (1 and 24h) after treatment, it was equivalent to control after 7 days. Moreover, histopathological analysis revealed no evidence of changes that could be attributed to cobalt pretreatment. It is therefore reasonable to conclude that the present study supports further use of the present dose of CoCl(2), which was found to be nontoxic.

Aim: Training under hypoxia has several advantages over normoxic training in terms of enhancing the physical performance. Therefore, we tested the protective effect of hypoxia preconditioning by hypoxia mimetic cobalt chloride against exercise-induced oxidative damage in the skeletal muscles and improvement of physical performance. Method: Male Sprague–Dawley rats were randomly divided into four groups (n = 8), namely control, cobalt-supplemented, training and cobalt with training. The red gastrocnemius muscle was examined for all measurements, viz. free radical generation, lipid peroxidation, muscle damage and antioxidative capacity. Results: Hypoxic preconditioning with cobalt along with training significantly increased physical performance (33%, P

Spiral-wound modules of solvent stable integrally skinned asymmetric nanofiltration membranes made from polyaniline (PANI) are reported. PANI membranes were made by phase inversion and crosslinked by chemical and thermal processes. In the chemical crosslinking process, PANI membrane cast on polypropylene non-woven backing was crosslinked using glutaraldehyde, and a 1.8 in. spiral-wound module was prepared. To crosslink membranes thermally, a 1.8 in. spiral-wound membrane module prepared from PANI membrane cast on polyester non-woven backing was heated at 180 °C for 2 h. The resultant membranes and modules were found to be stable in various organic solvents including acetone, tetrahydrofuran and N,N -dimethyl formamide. Filtrations carried out in acetone, tetrahydrofuran and dimethyl formamide gave stable permeate fluxes and good separation performances in the nanofiltration range. Molecular weight cut-off (MWCO) of the membranes was dependent on the nature of the solvent and temperature. MWCO of PANI membranes in different solvents was found to lie between 150 and 300 g mol −1 at 30 °C. The membranes were also found to be stable for operations at elevated temperatures up to 65 °C and possibly higher. These membranes retain their nanofiltration properties even after drying so the use of conditioning or preservative agents can be avoided.

Heat shock proteins (Hsps) have been reported to be dominant antigens for the host immune response to various pathogens and thus, have great potential for use in vaccination. In the present study, we evaluated the immunogenicity and protective efficacy of GroEL of Salmonella enterica serovar Typhi against lethal infection by S. typhi Ty2 in mice with or without adjuvants. Anti GroEL-IgG titers were significantly higher in mice immunized with either GroEL-alone or in combination with alum/Complete Freund's adjuvant (CFA) as compared to the control. Analysis of antibody isotypes suggested predominance of Th2 type immune response in GroEL + alum immunized animals as revealed by higher IgG1/IgG2a ratio. Whereas, immunization of animals with GroEL + CFA or GroEL-alone shifted the immune response toward Th1 phenotype. Mice immunized with GroEL with or without adjuvants, showed a significant increase in lymphocyte proliferation and cytokine levels. The animals immunized with GroEL + CFA or GroEL-alone showed higher IFN-gamma and IL-2 levels than alum group, indicating Th1 response whereas IL-4 levels (Th2 response) were found to be highest in alum group as compared to other two immunized groups. Immunization of mice with GroEL-alone, GroEL + alum, and GroEL + CFA provided 70, 50 and 80% protection, respectively, against lethal challenge by S. typhi in mice. The differences in the percentage protection among various groups were attributed to the differences in the immune responses generated by respective immunizations. The present study shows that GroEL forms an ideal candidate molecule to develop a recombinant protein based vaccine against human typhoid.

Shukla, Dhananjay, Saurabh Saxena, Purushotman Jayamurthy, Mustoori Sairam, Mrinalini, Singh, Swatantra Kumar Jain, Anju Bansal, and Govindaswamy Ilavazaghan. High Alt. Med. Biol. 10:57-69, 2009.-Hypoxic preco759nditioning (HPC) provides robust protection against injury from subsequent prolonged hypobaric hypoxia, which is a characteristic of high altitude and is known to induce oxidative injury in lung by increasing the generation of reactive oxygen species (ROS) and decreasing the effectiveness of the antioxidant defense system. We hypothesize that HPC with cobalt might protect the lung from subsequent hypobaric hypoxia-induced lung injury. HPC with cobalt can be achieved by oral feeding of CoCl(2) (12.5 mg kg(-1)) in rats for 7 days. Nonpreconditioned rats responded to hypobaric hypoxia (7619 m) by increased reactive oxygen species (ROS) generation and a decreased GSH/GSSG ratio. They also showed a marked increase in lipid peroxidation, heat-shock proteins (HSP32, HSP70), metallothionins (MT), levels of inflammatory cytokines (TNF-alpha, IFN-gamma, MCP-1), and SOD, GPx, and GST enzyme activity. In contrast, rats preconditioned with cobalt were far less impaired by severe hypobaric hypoxia, as observed by decreased ROS generation, lipid peroxidation, and inflammatory cytokine release and an inceased GSH/GSSG ratio. Increased expression of antioxidative proeins Nrf-1, HSP-32, and MT was also observed in cobalt- preconditioned animals. A marked increase in the protein expression and DNA binding activity of hypoxia-inducible transcriptional factor (HIF-1alpha) and its regulated genes, such as erythropoietin (EPO) and glucose transporter-1 (glut-1), was observed after HPC with cobalt. We conclude that HPC with cobalt enhances antioxidant status in the lung and protects from subsequent hypobaric hypoxia-induced oxidative stress.

A new family of functional materials is reported for organic solvent nanofiltration, with excellent chemical stability and high retention of solute molecules. Integrally skinned asymmetric polyaniline (PANI) membranes were fabricated from concentrated solutions of doped PANI by phase inversion. Doped PANI solutions were prepared by adding organic acids directly to PANI dissolved in a mixture of NMP and 4-methyl piperidine before casting. Among the organic acids investigated, maleic acid, phthalic acid, sulfosalicylic acid and camphorsulfonic acid were able to dope PANI without causing gelation. These acids acted as soft templates, creating nanoporosity in the thin skin layer of the asymmetric PANI film. Their removal by alkaline extraction created membranes through which small solvent molecules can pass. After extracting the organic acids, the membranes were thermally crosslinked which conferred excellent solvent stability. These membranes had a molecular weight cut-off (MWCO) in the range of 150–250 g mol−1 in methanol, making them the tightest OSN membranes reported to date. It was found that an increase in crosslinking temperature or time led to a decrease in solvent flux. PANI membranes were found to be resistant to a variety of organic solvents such as ethyl acetate, acetonitrile and acetone. These remarkable membranes have the potential to be used in OSN operations at high temperatures (up to 150 °C), and gave increasing fluxes with increasing temperature while maintaining a high solute rejection.

Solvent stable integrally skinned asymmetric nanofiltration membranes were prepared from polyaniline. These membranes were made by phase inversion and then crosslinked using two different chemical crosslinkers, α,α′-dichloro- p -xylene and glutaraldehyde. The resultant membranes were found to be stable in various organic solvents including acetone, methanol, ethyl acetate, tetrahydrofuran and N , N -dimethyl formamide. Nanofiltration experiments carried out in acetone and dimethyl formamide showed that the membranes gave stable permeate fluxes and good separation performances in the nanofiltration range. Molecular weight cut-off (MWCO) of the membranes was found to be between 150 and 250 g mol −1 . These membranes were also found to be stable for operations at elevated temperatures up to 70 °C and possibly higher. Furthermore, no fillers or preservative agents are required to maintain the membranes in a dry state thereby increasing the ease of handling.

Hypobaric hypoxia, characteristic of high altitude is known to increase the formation of reactive oxygen and nitrogen species (RONS), and decrease effectiveness of antioxidant enzymes. RONS are involved and may even play a causative role in high altitude related ailments. Brain is highly susceptible to hypoxic stress and is involved in physiological responses that follow. Exposure of rats to hypobaric hypoxia (7619 m) resulted in increased oxidation of lipids and proteins due to increased RONS and decreased reduced to oxidized glutathione (GSH/GSSG) ratio. Further, there was a significant increase in superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione-S-transferase (GST) levels. Increase in heme oxygenase 1 (HO-1) and heat shock protein 70 (HSP70) was also noticed along with metallothionein (MT) II and III. Administration of cobalt appreciably attenuated the RONS generation, oxidation of lipids and proteins and maintained GSH/GSSH ratio similar to that of control cells via induction of HO-1 and MT offering efficient neuroprotection. It can be concluded that cobalt reduces hypoxia oxidative stress by maintaining higher cellular HO-1 and MT levels via hypoxia inducible factor 1alpha (HIF-1alpha) signaling mechanisms. These findings provide a basis for possible use of cobalt for prevention of hypoxia-induced oxidative stress.

High throughput screening is commonly defined as automatic testing of potential drug candidates at a rate in excess of 10,000 compounds per week. The aim of high throughput drug discovery is to test large compound collections for potentially active compounds ('hits') in order to allow further development of compounds for pre-clinical testing ('leads'). High throughput technology has emerged over the last few years as an important tool for drug discovery and lead optimisation. In this approach, the molecular diversity and range of biological properties displayed by secondary metabolites constitutes a challenge to combinatorial strategies for natural products synthesis and derivatization. This article reviews the approach of High throughput technique for the screening of natural products for drug discovery.

Benzoyl peroxide was used as a novel oxidizing agent in the preparation of a polyaniline (PANI) dispersion. Aniline was oxidized by benzoyl peroxide into a PANI dispersion in the presence of poly(vinyl pyrrolidone) (PVP) as a stabilizer. A pure PANI dispersion in water was prepared by the dispersion of the isolated wet and dry forms of PANI powder. The size of the PANI particles in the water medium was measured for the reaction mixture and wet and dry composites with a particle size analyzer and a zeta sizer. The hydrodynamic diameter of the PANI particles ranged from 435 to 970 nm. The size of the PANI particles was found to be lower in the wet composite. PANI particles with a lower volume mean diameter (140 nm) and narrow size distribution (100–190 nm) were observed in the PANI–PVP wet composite. The PANI dispersion was characterized with Fourier transform infrared, ultraviolet–visible, differential scanning calorimetry, and scanning electron microscopy measurements. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

A novel semi-interpenetrating (semi-IPN) graft copolymer of 2-hydroxyethyl methacrylate (HEMA) with chitosan (CS) has been prepared in the form of microspheres, using water-in-oil (W/O) emulsion technique. Microspheres were characterized by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and X-ray diffractometry (X-RD) to confirm the crosslinking and polymorphism of indomethacin (IDM). The X-RD and DSC techniques indicated a molecular-level dispersion of IDM in the IPN matrix. Scanning electron micrographs (SEM) taken at the cross section of the microspheres have shown rough surfaces around the microspheres. The sustained release characteristics of the matrices for IDM, an anti-inflammatory drug, were investigated in pH 7.4 media. Particle size and size distribution of the microspheres were studied by laser light diffraction particle size analyzer. The drug was released in a sustained manner for up to 12 h. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci, 2006

Mixed matrix membranes of poly(vinyl alcohol) (PVA), loaded with phosphomolybdic heteropolyacid (HPA) and crosslinked with glutaraldehyde have been prepared by the solution casting technique. Pervaporation (PV) experiments have been performed at 30 °C to separate water–isopropanol feed mixtures containing 10–40 wt.% of water. The membranes were characterized by differential scanning calorimetry (DSC) and dynamic mechanical thermal analyzer (DMTA) to understand their thermal behavior and mechanical strength properties. At high content (i.e. 7 wt.% with respect to weight of PVA) of HPA, the mixed matrix membranes could extract water efficiently on the permeate side with a selectivity of 90,000 and a flux of 0.032 kg/m 2 h for 10 wt.% of water containing feed mixture (the lowest feed composition of water studied). Flux of the mixed matrix membranes decreased with increasing concentrations of HPA; however, a significant improvement in PV performance was observed for HPA-loaded membranes than the pristine PVA. DSC and DMTA analyses indicated a decrease in melting temperature and an increase in glass transition temperature, respectively.

Carbohydrate polymeric blend microspheres, consisting of sodium alginate (NaAlg) and methylcellulose (MC) were prepared by water-in-oil (W/O) emulsion method. These microspheres were cross-linked with glutaraldehyde and loaded with nifedipine (NFD), an anti-inflammatory drug. The microspheres were characterized by differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and laser particle size analyzer. DSC thermograms of NFD-loaded NaAlg–MC microspheres confirmed the molecular level distribution of NFD in the polymer matrix. SEM picture of the microspheres suggested the formation of spherical particles. Swelling experiments on the microspheres provided important information on drug diffusion properties. Release data have been analyzed using an empirical equation to understand the nature of transport of drug containing solution through the polymeric matrices. The controlled release characteristics of the matrices for NFD were investigated in pH 7.4 media. Particle size and size distribution of the microspheres was studied by laser light diffraction particle size analyzer. Drug was released in a controlled manner up to 12 h.

Silicotungstic acid incorporated sodium alginate (STA-NaAlg) hybrid composite membranes were prepared by incorporating 1, 2, 3 and 5 wt.% of silicotungstic acid (STA) into sodium alginate (NaAlg) and crosslinked with glutaraldehyde. Scanning electron microscopy and universal testing machine were used to investigate the morphology and the mechanical strength properties of the membranes. These membranes were tested for pervaporation (PV) dehydration of acetic acid at lower water concentrations of 10–25 wt.% in the feed. Addition of STA into NaAlg could result in a dramatic increase of water selectivity over that of plain NaAlg membrane dehydrating acetic acid for lowest STA containing NaAlg membrane. Thus, infinite selectivity was observed for STA-NaAlg membrane containing 1 wt.% of STA for all feed mixture compositions ranging from 10 to 25 wt.% water. With increasing STA content from 2, 3 and 5 wt.% in NaAlg membranes, selectivities ranged from 22,491 to 288, 12,848 to 192 and 6914 to 108, respectively for the studied composition range of the feed mixtures. PV performances of STA-NaAlg hybrid composite membranes were also tested at 40, 50, 60 and 70 °C typically in case of 10 wt.% water-containing feed mixture, which indicated a decrease in selectivity and increase in flux for all hybrid composite membranes. Arrhenius plots of flux data versus reciprocal of temperature exhibited linear trends. The hydrophilic STA is responsible to offer increased selectivity and flux to water as compared to plain NaAlg membrane for the feed mixtures studied. Of all the membranes tested, the 1 wt.% STA containing NaAlg membrane exhibited the best PV performance characteristics. Temperature did not influence much the selectivity data of STA-NaAlg membrane containing 1 wt.% of STA up to 50 °C, but flux increased with increasing temperature for all membranes. The results of this study are far superior to the previously reported data on acetic acid dehydration by the PV technique.

The present paper is our continuing effort to develop a new type of sodium alginate (NaAlg) composite membrane by incorporating cobalt(III)(3-acetylpyridine-o-aminobenzoylhydrazone) (Co-APABZ) complex as filler particles in different ratios. Membranes were prepared by solution casting followed by solvent evaporation and crosslinked with glutaraldehyde. Pervaporation (PV) performance of the prepared composite membranes was assessed in terms of flux and selectivity and these data were compared with the pristine NaAlg membrane in PV dehydration of water–acetic acid mixtures. Pristine Co-APABZ particles in crystalline form were prepared and characterized by the solid state X-ray diffraction (XRD) technique, while the NaAlg/Co(III)composite membranes were characterized by thermogravimetry (TGA) and dynamic mechanical thermal analyzer (DMTA). X-ray crystal structure of Co-APABZ has shown that the complex formed was crystalline in nature with six lattice water molecules, which are interconnected by hydrogen bonds linking together to form cyclic hexamers that are analogous to cyclohexane, creating water channels for an easy transport of water molecules. TGA indicated no changes in thermal stability of the membranes due to the presence of Co-APABZ in the NaAlg matrix. DMTA confirmed NaAlg crosslinking with glutaraldehyde. Effects of Co-APABZ content, membrane thickness, temperature and feed water compositions on membrane performance were investigated to find an optimum PV performance of the membranes developed. NaAlg composite membranes in the presence of Co-APABZ particles preferentially absorbed water molecules to facilitate diffusion of water through the membranes and thus enhance the selectivity to water. However, the amount of Co-APABZ present in the NaAlg matrix and the degree of membrane swelling has an effect on membrane performance. Selectivity of 174 for water with a flux of 0.123 kg/m2 h was obtained for 5 wt.% Co-APABZ containing NaAlg matrix, when tested for the feed mixture containing 10 wt % water. The present results are superior to the previously published data based on NaAlg membranes.

Molecular modeling simulations are the most important tools to predict blend compatibility of polymers that are otherwise difficult to predict by experimental means. Conflicting reports have been reported on the blend compatibility of poly(vinyl alcohol), PVA, and chitosan, CS polymers. Since both the polymers are widely used in pharmaceutics as drug-loaded particulates and as separation membranes, we felt it necessary to investigate their compatibility over the practical range of compositions. In this paper, we attempt to study the compatibility of PVA and CS polymers using molecular modeling strategies to understand the interactions between CS and PVA polymers to predict their compatibility from atomistic simulations. Flory-Huggins interaction parameter, chi, was computed at 298 K to assess the blend compatibility at different ratios of the component polymers. Miscibility was observed for blends below 50% of PVA, while immiscibility was prevalent at compositions between 50 and 90% PVA. Computed results confirmed the experimental findings of dynamic mechanical thermal analysis, suggesting the validity of modeling strategies employed. Plots of Hildebrand solubility parameter and cohesive energy density calculated at 298 K supported these findings. The chi values for blends, which satisfied the criteria of miscibility of polymers computed by atomistic simulations, agreed with the solubility criteria related to order parameters calculated from mesoscopic simulations. Miscibility between PVA and CS polymers is attributed to hydrogen bond formation and to an understanding of which of the interacting groups of CS, i.e., -CH2OH or -NH2, are responsible in blend miscibility. This was further confirmed by molecular dynamics simulations of radial distribution functions for groups or atoms that are tentatively involved in interactions. These results are correlated well to obtain more realistic information about interactions involved as a function of blend composition. Computed free-energy from the mesoscopic simulation for blends reached equilibrium, particularly when the simulation was performed at higher time step, indicating stability of the blend system at certain compositions.

With the density and viscosity results for five polymers—poly(vinyl alcohol) (PVA), poly(vinyl pyrrolidone) (PVP), gelatin (Ge), starch (St), and carboxymethylcellulose (CMC)—measured in aqueous solutions at different temperatures, we have computed the excess molar volumes and activities. Smaller excess molar volumes for PVA solutions are attributed to specific types of interactions, whereas for other polymers, these data are quite large, indicating dispersion-type interactions. The activity data of the polymer solutions vary widely, depending on the nature of the polymers and their intermolecular interactions. The freestanding film properties of the polymers indicate that Ge and PVA produce stable films, whereas brittle films can be obtained for PVP and St. The mechanical strength properties of PVA and CMC have been found to be suitable for membrane fabrication. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007

Mixed matrix polymer membranes containing nanosized (21 nm) TiO2 particles dispersed in sodium alginate (NaAlg) have been prepared by solution casting and cross-linking with glutaraldehyde. These membranes were tested for pervaporation (PV) dehydration of tetrahydrofuran (THF) and isopropanol from their aqueous solutions at 30°C. Results have been compared with plain cross-linked NaAlg membrane. Plain cross-linked NaAlg membrane could remove up to a maximum of 97 wt% of water at higher feed water concentrations of the feed with considerably much lower selectivity. Infinite selectivity values with reasonable fluxes were observed for the mixed matrix membranes of NaAlg in the investigated feed compositions of 5–15 wt% water containing THF and 10–20 wt% of water containing isopropanol feed mixtures. Fluxes of NaAlg-TiO2 mixed matrix membranes are slightly lower than those of plain the NaAlg membrane for the investigated range of feed water compositions.

Nanocomposites of modified chitosan, carboxymethyl chitosan (CMCh) with hydroxyapatite (HAP) have been prepared by coprecipitation technique. Totally three nanocomposites containing 80/20, 50/50, and 20/80 of HAP/CMCh have been prepared and were characterized by using transmission electron microscopy (TEM), X-ray diffraction (XRD), fourier transformed infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), thermogravimetry (TG), and scanning electron microscopy (SEM). Modified chitosan, CMCh, which is water soluble can be used for drug delivery application. TEM micrographs of the nanocomposites revealed the formation of small HAP crystallites of about 230 nm in length and 30 nm in width that are aggregated to form elliptical shapes or morphology. TGA thermograms showed that the thermal stability of the CMCh increased with incorporation of HAP. FTIR, XRD, and XPS analysis of CMCh/HAP nanocomposites showed the peaks corresponding to CMCh as well as HAP and confirm the formation of HAP/CMCh nanocomposites. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007

Cellulose acetate butyrate-poly(vinyl pyrrolidone) (CAB-PVP) blend microspheres were prepared using the solvent evaporation technique using poly(vinyl alcohol) as an emulsifying agent. Atenolol (ATNL), an antihypertensive drug, was successfully loaded into these microspheres. Effect of experimental variables such as CAB/PVP ratio on ATNL encapsulation efficiency, release rate, size and morphology of the microspheres has been investigated. ATNL-loaded microspheres were analyzed using differential scanning calorimetry to investigate the crystalline nature of ATNL after encapsulation. DSC results indicated a non-uniform dispersion of ATNL in CAB-PVP blend matrix. Scanning electron micrographs indicated the formation of spherical microspheres. Mean particle size of the microspheres, as measured by the laser light scattering technique, ranged between 100 and 120 μm. An encapsulation of about 80% of ATNL was achieved. In vitro dissolution experiments performed in pH 7.4 buffer medium indicated the controlled re...

Semi-interpenetrating network (IPN) of sodium alginate (NaAlg) and N-isopropylacrylamide (NIPAAm) microspheres were prepared by water-in-oil (w/o) emulsification method. The microspheres were encapsulated with 5-fluorouracil (5-FU) and release patterns carried in 7.4 pH at temperatures of 25 and 37°C. The semi-IPN microspheres were characterized by Fourier transform infrared spectroscopy (FTIR). Differential scanning calorimetry (DSC) and scanning electron microscopic studies were done on the drug-loaded microspheres to confirm the polymorphism of 5-FU and surface morphology of microspheres. These results indicated the molecular level dispersion of 5-FU in the semi-IPN microspheres. Particle size and size distribution were studied by laser light diffraction technique. Microspheres exhibited release of 5-FU up to 12 h. The swelling studies were carried in 1.2 and 7.4 pH buffer media at 25 and 37°C. Drug release from NaAlg-NIPAAm semi-IPN microspheres at 25 and 37°C confirmed the thermosensitive nature by in vitro dissolution. The micro domains have released in a controlled manner due the presence of NIPAAm in the matrix. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Poly(methylmethacrylate)-poly(vinyl pyrrolidone) (PMMA-PVP) microspheres loaded with cefadroxil (water-soluble) and indomethacin (water-insoluble) drugs have been prepared by the dispersion polymerization technique using PVP as a steric stabilizer. Microspheres have been characterized by differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and X-ray diffraction (X-RD) studies. DSC studies indicated coating of PVP onto PMMA microspheres. SEM suggested the formation of microspheres in the size of around 5 μm. X-RD confirmed that drug has been highly dispersed in polymer particles. Higher encapsulation efficiency of up to 84% was achieved for hydrophobic drug, indomethacin than for hydrophilic cefadroxil. In vitro release studies performed in pH 7.4 phosphate buffer saline indicated that release of indomethacin was controlled up to 12 h, whereas cefadroxil was released in a controlled manner up to 10 h. During in vitro release, properties of both the drugs remained unaltered. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1860–1865, 2007

In this paper, excess thermodynamic functions have been computed from the measured values of density, viscosity, and refractive index at T = (298.15, 303.15, and 308.15) K, ultrasonic velocity at T = 298.15 K over the entire mixture composition range of (anisole with ethanol, propan-1-ol, propan-2-ol, butan-1-ol, pentan-1-ol, or 3-methyl butan-1-ol). Excess molar volume, VE has been calculated from densities, whereas deviations in viscosity, Δη, were computed from the measured viscosities. From ultrasonic velocities, isentropic compressibilities were calculated, from which deviations in isentropic compressibility, Δks have been computed. Lorenz–Lorentz mixture rule was used to compute molar refractivity, R from refractivity index data and from these data, deviations in molar refractivity, ΔR have been computed. Computed thermodynamic quantities have been fitted to Redlich and Kister polynomial equation to derive the coefficients and standard errors between experimental and predicted quantities. Intermolecular interactions between anisole and alkanols have been studied based on the computed excess thermodynamic quantities.

Conjugated polymers are excellent barriers for membrane separations because their porosity can be controlled at the molecular level through chemical doping. Polyaniline (PANI) is particularly attractive because simple acid/base doping/undoping enables a controllable level of doping that can be readily achieved using dopants of different sizes and shapes. PANI, which belongs to an important member of the family of electrically conducting polymers, has been studied extensively as a membrane due to its distinct electrochemical properties and environmental stability. Adding dopants to PANI leads to a decrease in gas permeability, while removal of these dopants would produce extremely high permeability. This review provides an overview of the use of PANI membrane in gas separation (GS), pervaporation (PV) and electrodialysis (ED) applications. Our discussion will be concerned with the utility of PANI as a homopolymer, blend and composite membrane, discussing a considerable amount of background informa...

Due to the widespread usage of carbohydrate polymers in a variety of areas, the present study is undertaken to develop novel graft copolymers of hydroxyethylcellulose and acrylamide (HEC-g-AAm). Grafting reaction was confirmed by Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC). The graft copolymers were blended in different ratios with a natural polymer, sodium alginate (NaAlg). Using these polymers, membranes were prepared by solution casting and were crosslinked with glutaraldehyde for testing in pervaporation (PV) dehydration of acetic acid. Swelling experiments have been performed on the blend membranes at 30 °C to test their stability in water–acetic acid mixtures. The present membranes, being hydrophilic, were able to successfully recover 89% of water from acetic acid solutions when tested for feed mixtures ranging from 10% to 50% (w/w) of water. Membrane flux and selectivity to water was increased at increasing amount of HEC-g-AAm grafted copolymer in the mixed blend of NaAlg. The membranes of this study showed selectivity of 27.9 with a flux of 0.058 kg/m2 h to dehydrate 10% (w/w) water from aqueous acetic acid feed mixture through the blend membrane. Flux values increased with increasing concentration of water in the feed, while selectivity decreased considerably. To the best of our knowledge, this is indeed the first example of the use of this type of combination carbohydrate polymers for pervaporation dehydration of acetic acid, which is a well-known industrial solvent.

Experimental values of density, viscosity, and refractive index at 298.15, 303.15, and 308.15 K have been measured over the whole range of composition for the binary liquid mixtures of mesitylene with ethanol, propan-1-ol, propan-2-ol, butan-1-ol, pentan-1-ol, and 3-methylbutan-1-ol. Using these data, excess molar volumes, deviations in viscosity, and Lorenz–Lorentz molar refractivity have been calculated. These results have been fitted to Redlich and Kister polynomial equation to derive the coefficients and standard errors. These quantities have been discussed in terms of the intermolecular interactions between the components of the mixtures.

Poly(vinyl alcohol)-based mixed matrix membranes loaded with 5 and 10 wt.% of sodium montmorillonite (Na + MMT) clay particles, i.e. (PVA/Na + MMT-5 and PVA/Na + MMT-10), were fabricated by solvent casting method. The uncrosslinked membranes were used in pervaporation (PV) dehydration of aqueous solutions of isopropanol and 1,4-dioxane at 30 °C. Membrane morphology was characterized by scanning electron microscopy. Differential scanning calorimetry, thermogravimetric analysis and dynamic mechanical thermal analysis were used to understand thermal properties. Universal testing machine was used to study mechanical strength properties. Separation factor to water has increased from 1116 to 2241 for PVA/Na + MMT-5 and PVA/Na + MMT-10 mixed matrix membranes when tested for 10 wt.% water-containing isopropanol feed, but the corresponding flux values of 0.051 and 0.075 kg/m 2 h were somewhat lower than those observed for pristine PVA membrane. On the other hand, for water + 1,4-dioxane feed mixtures, separation factors were quite lower and ranged from 216 to 369 with the corresponding flux values of 0.076 and 0.093 kg/m 2 h, respectively, for PVA/Na + MMT-5 and PVA/Na + MMT-10 membranes at 10 wt.% water in the feed. Membranes of this study could extract up to 99.20 and 99.60 wt.% water on the permeate side from water–isopropanol mixture, while from water–1,4-dioxane mixture, only 96.0 and 97.62 wt.% of water were removed for 10 wt.% water-containing feed. The membranes were further tested for PV at 40, 50 and 60 °C for 10 wt.% of water-containing feeds of aqueous isopropanol and 1,4-dioxane solutions to confirm their stability at higher temperatures. Plots of ln J p versus 1/ T are linear in the studied range of 30–60 °C for both the feed mixtures, indicating that flux follows an Arrhenius trend. PV results are discussed in terms of water flux, separation factor, permeation separation index, enrichment factor and activation energy of permeation. Sorption and PV experiments were carried out for the thermally crosslinked and glutaraldehyde crosslinked PVA/Na + MMT mixed matrix membranes for 10 wt.% water-containing feed mixtures at 30 °C. A small increase in separation factor with a slight sacrifice in flux was observed without showing any great difference as compared to uncrosslinked mixed matrix membranes. The hydrophilic nature of Na + MMT clay and the formation of PVA/Na + MMT mixed matrix membranes are responsible to offer such increased separation to water over the organic components of the feed mixtures.

Novel poly(acrylamide-methylmethacrylate) copolymeric core-shell microspheres crosslinked with N,N'-methylene bisacrylamide have been prepared by free radical emulsion polymerization using varying amounts of acrylamide (AAm), methylmethacrylate (MMA) and N,N'-methylene bisacrylamide (NNMBA). 5-Fluorouracil was loaded into these microspheres during in situ polymerization (method-I) as well as by the absorption and adsorption technique (method-II). The core-shell microspheres have been characterized by differential scanning calorimetry (DSC) and X-ray diffractometry (X-RD) to understand about the drug dispersion in microspheres. Scanning electron microscopy (SEM) was used to assess the surface morphology of particles prepared. In vitro release of 5-fluorouracil has been studied in terms of core-shell composition, amount of crosslinking agent and amount of 5-fluorouracil in the microspheres. Core-shell microspheres with different copolymer compositions have been prepared in yields ranging 80-85%. DSC and X-RD techniques indicated a uniform distribution of 5-fluorouracil particles in core-shell microspheres, whereas SEM suggested the formation of well-defined core-shell structures. The in vitro drug release indicated that particle size and release kinetics depend upon copolymer composition, amount of crosslinking agent used and amount of 5-fluorouracil present in the microspheres. Prolonged and controlled release of 5-fluorouracil was achieved when drug was loaded by method-I instead of method-II.

This paper addresses development of novel pH-sensitive interpenetrating polymeric network (IPN) microgels (MGs) based on chitosan, acrylamide-grafted-poly(vinyl alcohol) and hydrolyzed acrylamide-grafted-poly(vinyl alcohol) that are crosslinked with glutaraldehyde and used in the controlled release (CR) of cefadroxil, an antibiotic drug. The MGs formed were characterized by Fourier transform infrared spectroscopy to confirm the grafting and crosslinking reaction, scanning electron microscopy to understand the surface morphology and differential scanning calorimetry to conform a uniform distribution of the drug in the polymer matrix. Swelling experiments on hydrogels provided important information on drug diffusion properties. In vitro release results performed in acidic and basic media affected the drug release characteristics. Release data have been analyzed using an empirical equation to understand about the transport of drug containing solution through the polymeric matrices. Extent of crosslinking was studied in terms of size of MGs as well as their release characteristics. Effect of drug loading on encapsulation efficiency was investigated to find a linear manner. IPN matrices of this study were able to extend the release rates from conventional dosage release times to more than 10 h.

Poly(vinyl alcohol) (PVA)-based nanocomposite membranes were prepared by coprecipitation of different amounts of Fe(II) and Fe(III) taken in an alkaline medium and their pervaporation (PV) performances were investigated to dehydrate isopropanol, 1,4-dioxane and tetrahydrofuran (THF) from aqueous feeds containing 10–20 wt.% of water in isopropanol and 1,4-dioxane, 5–l5 wt.% of water in THF. The freestanding membranes were characterized by the dynamic mechanical thermal analyzer (DMTA), which showed a shift in glass transition temperature toward higher range along with an increase in storage modulus with increasing amount of iron oxide in the PVA matrix. Furthermore, thin layered membranes were cast on polyester fabric cloths as support layers to improve their PV separation performances for all the three mixtures over that of the pristine crosslinked PVA membrane. In particular, the composite membrane prepared by taking 4.5 wt.% of iron oxide showed an improved selectivity with a slight sacrifice in flux compared to membranes containing lower contents of iron oxide as well as the pristine crosslinked PVA membrane. Flux decreased with increasing content of iron in the PVA matrix, while selectivity increased systematically.

Two novel organopolyphosphazenes viz., poly[bis(4-methoxy benzylamino)polyphosphazene] (POP-1) and poly[bis(4-methoxyphenethylamino)polyphosphazene] (POP-2) have been synthesized by replacing chlorine atoms of polydichlorophosphazene with 4-methoxybenzylamine and 4-methoxyphenethylamine. These polymers have been characterized by FTIR, 1 H, 13 C and 31 P NMR. Polymers prepared have been subjected to DSC and TGA analysis to determine their glass transition temperature and thermal stability. Microspheres have been prepared by incorporating indomethacin (water insoluble) and 5-fluorouracil (water soluble) drugs. In vitro release characteristics of indomethacin was performed in 7.4 pH media, while for 5-fluorouracil, release studies were performed in both pH 7.4 and 1.2 buffer media. The % cumulative release of indomethacin increased with increasing drug loading. Sustained release was achieved at lower loadings of indomethacin, but for 5-fluorouracil, release was achieved in pH 1.2 media and the release was fast in pH 7.4 buffer media.

Novel poly(vinyl alcohol)–titanium dioxide (PVA–TiO2) mixed matrix membranes have been prepared by incorporating nano-sized titanium dioxide (21 nm) and titanium dioxide surface modified with polyaniline (PANI) into PVA and crosslinked with glutaraldehyde. The developed membranes have been assessed for intermolecular interactions using Fourier transform infrared (FTIR), X-ray diffraction (XRD) and differential scanning calorimetry (DSC) techniques to understand their morphological and thermal properties. Suitability of these membranes to dehydrate isopropanol by pervaporation (PV) has been demonstrated. The effect of feed composition as well as extent of filler loading on the PV separation performance of these membranes has been evaluated. Sorption studies have been carried out to evaluate the extent of interaction and degree of swelling of the membranes in pure liquids as well as feed mixtures of water and isopropanol. Addition of small amount of nano-sized filler particles into the crosslinked PVA membrane matrix has been instrumental in increasing the membrane selectivity to infinity values. The uncrosslinked mixed matrix PVA membranes have yielded higher swelling properties than those of the crosslinked ones. However, swelling results of the crosslinked (unfilled) PVA membranes are higher than all the mixed matrix membranes. The addition of filler particles has decreased the extent of swelling and the flux properties, giving an increase in selectivity.