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► We have developed poly(N-vinyl caprolactam-co-acrylamidoglycolic acid) based nanogels for controlled release of an anticancer drugs. ► This system exhibited dual responsive nature, ...and accelerated drug release profile. ► The cumulative release data were analysed using an emperical equation to compute the diffusion coefficient; it suggest Fickian diffusion.
A series of novel nanogels (NGs) with both pH and thermoresponsive properties were synthesised by free radical emulsion polymerisation of N-vinyl caprolactam (VCL) and acrylamidoglycolic acid (AGA). 5-Flurouracil, an anti cancer drug, was successfully loaded into these nanogels via equilibrium swelling method. The encapsulation efficiency of 5-FU was found up to 61%. Here we present the novel potential drug delivery system showing both pH and temperature release of 5-FU. Fourier transforms infrared spectroscopy (FTIR), and differential scanning calorimetric (DSC) examined the structure and morphology of the NGs. Transmission electron microscopy (TEM) indicates the diameter of the NGs to be about 50nm. The size distribution of NGs was investigated using dynamic light scattering (DLS), the average diameter and polydispersity is 57nm and 0.194. Interestingly, the in vitro release studies of 5-FU demonstrated the dual nature (pH and temperature) of NGs. The cumulative release data were analysed using an emperical equation to compute the diffusion exponent (n); whose values suggest Fickian diffusion.
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Interpenetrating polymeric network nanogels (IPN-NGs) composed of natural gelatin biological protein macromolecules and poly(acrylamidoglycolic acid) were produced by simple free ...radical emulsion polymerization. The developed IPN-NGs were characterized by Fourier-transform infra-red spectroscopy to confirm the formation of NGs. The hydrophobic curcumin drug was loaded successfully into these NGs using an in-situ method. The curcumin-encapsulated NGs were well dispersed in aqueous solutions and showed good bioavailability. Curcumin was dispersed molecularly in the IPN-NGs, which was confirmed by differential scanning calorimetry and X-ray diffraction. The NGs exhibited pH sensitive properties according to dynamic light scattering and the zeta size potentials. Transmission electron microscopy revealed the NGs to be spherical, approximately 100nm in size. The encapsulation efficiency of these IPN-NGs drug formulations ranged from 42 to 48%. In addition, the release of curcumin from the NGs was examined in phosphate buffer medium. The cytotoxicity of the IPN-NGs was studied using in vitro cultures of fibroblasts and a colorectal cancer cell line. The results suggest that the newly developed pH sensitive gelatin-poly(acrylamidoglycolic acid)-curcumin NGs can be applied for colorectal cancer drug delivery applications.
The study was planned to screen the marine actinobacterial extract for the protease inhibitor activity and its anti- Pf activity under in vitro and in vivo conditions. Out of 100 isolates, only 3 ...isolates exhibited moderate to high protease inhibitor activities on trypsin, chymotrypsin and proteinase K. Based on protease inhibitor activity 3 isolates were chosen for further studies. The potential isolate was characterized by polyphasic approach and identified as Streptomyces sp LK3 (JF710608). The lead compound was identified as peptide from Streptomyces sp LK3. The double-reciprocal plot displayed inhibition mode is non-competitive and it confirms the irreversible nature of protease inhibitor. The peptide from Streptomyces sp LK3 extract showed significant anti plasmodial activity (IC50: 25.78 µg/ml). In in vivo model, the highest level of parasitemia suppression (≈ 45%) was observed in 600 mg/kg of the peptide. These analyses revealed no significant changes were observed in the spleen and liver tissue during 8 dpi. The results confirmed up-regulation of TGF-β and down regulation of TNF-α in tissue and serum level in PbA infected peptide treated mice compared to PbA infection. The results obtained infer that the peptide possesses anti- Pf activity activity. It suggests that the extracts have novel metabolites and could be considered as a potential source for drug development.
To transmit electric power to long distance load centers HVDC transmission lines are widely used in recent years. Insulators are one of the vital equipment in transmission lines and are exposed to ...different ambient atmospheric pollution. In some cases, may be due to either of very high pollution and/ or improper dimensioning, a flashover may occur across insulation at normal operating voltage. Such unwanted flashover may be avoided by optimum design and dimensioning of insulators. Pollution performance studies in many cases determines the dimensioning of insulators. IEC TS 61245 gives guidelines to perform artificial pollution test on glass and ceramic insulators, intended for HVDC application. Now a days, due to inherent advantages, utilities are using composite insulators and till date no standardized test procedure is available to conduct artificial pollution test on composite insulators. However, for optimum dimensioning of composite insulators a standard test procedure is mandatory. In this work following the guidelines of IEC TS 61245 and CIGRE WG C4.303 round robin test report 555, a laboratory developed test method is proposed to perform artificial pollution test on composite insulators intended for HVDC applications by solid layer method. Step by step procedure of proposed test method along with its validation in terms of representativeness and repeatability is reported. Reproducibility of developed method is validated successfully by performing test on large scale, ±500 kV composite insulators intended for HVDC applications.
This paper aims at introducing new natural fibers used as fillers in a polymeric matrix enabling production of economical and lightweight composites for load carrying structures. An investigation of ...the extraction procedures of vakka (
Roystonea regia), date and bamboo fibers has been undertaken. The cross-sectional shape, the density and tensile properties of these fibers, along with established fibers like sisal, banana, coconut and palm, are determined experimentally under similar conditions and compared. The fibers introduced in the present study could be used as an effective reinforcement for making composites, which have an added advantage of being lightweight.
Semiconductor metal oxides: Modifications, charge carrier dynamics and photocatalysis.
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•TiO2, WO3 and ZnO based photocatalysis is reviewed.•Advances to improve the efficiency are ...emphasized.•Differences and similarities in the modifications are highlighted.•Charge carrier dynamics for each strategy are discussed.
Metal oxide semiconductors (TiO2, WO3 and ZnO) finds unparalleled opportunity in wastewater purification under UV/visible light, largely encouraged by their divergent admirable features like stability, non-toxicity, ease of preparation, suitable band edge positions and facile generation of active oxygen species in the aqueous medium. However, the perennial failings of these photocatalysts emanates from the stumbling blocks like rapid charge carrier recombination and meager visible light response. In this review, tailoring the surface-bulk electronic structure through the calibrated and veritable approaches such as impurity doping, deposition with noble metals, sensitizing with other compounds (dyes, polymers, inorganic complexes and simple chelating ligands), hydrogenation process (annealing under hydrogen atmosphere), electronic integration with other semiconductors, modifying with carbon nanostructures, designing with exposed facets and tailoring with hierarchical morphologies to overcome their critical drawbacks are summarized. Taking into account the materials intrinsic properties, the pros and cons together with similarities and striking differences for each strategy in specific to TiO2, WO3 & ZnO are highlighted. These subtlety enunciates the primacy for improving the structure-electronic properties of metal oxides and credence to its fore in the practical applications. Future research must focus on comparing the performances of ZnO, TiO2 and WO3 in parallel to get insight into their photocatalytic behaviors. Such comparisons not only reveal the changed surface-electronic structure upon various modifications, but also shed light on charge carrier dynamics, free radical generation, structural stability and compatibility for photocatalytic reactions. It is envisioned that these cardinal tactics have profound implications and can be replicated to other semiconductor photocatalysts like CeO2, In2O3, Bi2O3, Fe2O3, BiVO4, AgX, BiOX (X=Cl, Br & I), Bi2WO6, Bi2MoO6, etc., to improve their competence for various environmental applications.
Cobalt-zinc ferrite nanoparticles having composition Co1-xZnxFe2O4 were processed by sol-gel method with particle sizes ranging from 10.8 nm to 3.6 nm. The crystal structure, particle size, and ...magnetic properties were investigated by XRD, FTIR, TEM, and VSM techniques. Single domain nature was established from the coercivity versus particle size curve. The dependence of specific saturation magnetization with zinc concentration was discussed in terms of site occupancy of cations and supported by FTIR measurements. A few single domain nanoparticle compositions exhibiting low Curie temperatures and reasonably good magnetization were subjected to induction heating measurement to explore the possibility of using the materials for magnetic hyperthermia. The material, having the composition, Co0.37Zn0.63Fe2O4 was shown to be an excellent candidate for conducting hyperthermia study with self-regulated temperature at 46 °C.
•Nanoparticles of size from 3.6 nm to 10.8 nm were synthesized by sol-gel method.•The chelating agent, polyvinyl alcohol was found to be powerful in controlling the particle size.•The transition from multi-domain to single domain nanoparticle was established with zinc concentration.•The composition Co0.37Zn0.63Fe2O4 was developed with Curie temperature, 46 °C.•Self regulated magnetic hyperthermia in the composition, Co0.37Zn0.63Fe2O4 was achieved.
Nanoparticles have several exciting applications in different areas and biomedial field is not an exception of that because of their exciting performance in bioimaging, targeted drug and gene ...delivery, sensors, and so on. It has been found that among several classes of nanoparticles core/shell is most promising for different biomedical applications because of several advantages over simple nanoparticles. This review highlights the development of core/shell nanoparticles-based biomedical research during approximately past two decades. Applications of different types of core/shell nanoparticles are classified in terms of five major aspects such as bioimaging, biosensor, targeted drug delivery, DNA/RNA interaction, and targeted gene delivery.
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•Core/shell nanoparticles are extensively used for biomedical applications.•Shell is important for better dispersibility, bio-functionalization, and optical property.•Major applications are in bioimaging, drug delivery, gene delivery, and sensors.
The present study was conducted on the river Yamuna, which passes through Delhi-NCR from Baghpat to Chhainssa, a distance of about 125 km, at six sampling locations to evaluate the concentrations of ...heavy metals in surface water using heavy metal pollution index (HPI) approach. The river serves both urban-industrial and rural areas in the study area; hence, domestic, industrial, and agricultural wastes are being contributed greatly in the contamination of river water. The Yamuna River is one of the major tributaries of the river Ganga originated in the Himalayas and is flowing through a varied geological terrain. Metals such as iron (Fe), copper (Cu), cobalt (Co), zinc (Zn), lead (Pb), cyanide (CN), nickel (Ni), and chromium (Cr) in selected sites of Yamuna River water were determined by using atomic absorption spectrophotometer. The concentrations of Fe, Cu, Co, Zn, Pb, CN, Ni, and Cr in the river water were found to be in the range of 40–190, 50–120, 4–66, 840–1800, 2–40, 100–600, 88–253, and 35–52 μg/L, respectively. The results show that the maximum heavy metal content was found at sampling site S3 (Nizamuddin) followed by S6 (Chhainssa), S4 (Okhla), S1 (Baghpat), S5 (Manjhawali), and S2 (Pachahira). The heavy metal data was integrated in GIS environment for preparing spatial distribution maps of sampling sites. A scatter plot matrix was created to assess the pattern and interrelationships between heavy metals. The average concentration of heavy metals was recorded high, often exceeding the permissible limits for drinking of surface water prescribed by the Bureau of Indian Standards (BIS) and World Health Organization (WHO). Based on HPI (varies from 98.2 to 555.1), about 85% of the river water was classified as highly polluted; hence, it is not recommended for drinking. Overall, significant variations were observed in concentrations of heavy metals from one location to the other which may be because of toxic industrial effluents and domestic sewage wastes being added to the river water by various anthropogenic activities in the study area. The present work highlights the pollution load of heavy metals in the river Yamuna and also advocates an urgent attention towards minimizing the health risk of people residing not only along the river banks and surrounding regions but also for city population.
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