Publications by authors named "Katiyar J"

Polymer coatings have gained a lot of attention in the recent past because of their ability to be easily coated on complex shapes, their low cost, and their ability to reduce friction as compared to other materials. Polyether ether ketone (PEEK) is one such high-performance polymer that has gained significant attention in recent years due to its exceptional mechanical properties, chemical resistance, and thermal stability making it a prominent candidate for applications in industries. However, PEEK in its pristine form exhibits poor wear resistance with a moderate coefficient of friction (0.

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Ablative composites serve as sacrificial materials, protecting underlying materials from high-temperature environments by endothermic reactions. These materials undergo various phenomena, including thermal degradation, pyrolysis, gas generation, char formation, erosion, gas flow, and different modes of heat transfer (such as conduction, convection, and radiation), all stemming from these endothermic reactions. These phenomena synergize to form a protective layer over the underlying materials.

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Article Synopsis
  • The study focuses on creating a pH-responsive fluorescent microgel named NANO-PAMAM-CHT for the selective detection of copper (Cu) and chromium oxide (CrO) ions.
  • The microgel is synthesized using simple and cost-effective materials through aza-Michael addition reactions in water and exhibits changes in fluorescence intensity based on pH levels.
  • NANO-PAMAM-CHT can effectively differentiate between Cu and CrO ions in aqueous solutions, with detection limits of 16.9 μM for Cu and 2.62 μM for CrO, both of which are below the safety threshold for drinking water.
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Despite significant advances in the field, quantitative post-polymer modification of chitosan, specifically attaching diverse hydrophobic moieties with experimentally predefined (via the ratio of reagents) degree of functionalization remain extremely challenging. In this context, we report our studies towards the use of green and efficient azetidinium-amine reactions to prepare a library of modified chitosan with a predefined degree of functionalization, with excellent conversion (>90%), atom economy and very low E-factor (<0.1).

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Remarkable progress has been established in the field of nanoenergetic materials (mixture of nanoscale fuel and oxidizer) since the advent of nanotechnology. Combustion of nanoenergetic materials depends on many key factors like synthesis route, equivalence ratio, morphology of constituents, and arrangements and handling of materials. For tailoring and tuning of the combustion properties of nanoenergetics, sound knowledge of the reaction mechanism is needed; in this review article a schematic study on the reaction mechanism is presented.

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Indian langurs, which were previously reported to be highly susceptible, were infected intradermally using variable numbers of promastigotes along with different doses, 1/2 pair, 5 pairs and 10 pairs respectively of salivary gland lysate (SGL). Although, all the monkeys developed mild infection and remained subclinically infected throughout the observation period, which later resolved, none of them could develop the classical disease. No marked antigen specific antibody or lymphoproliferative response was noticed throughout the experimental period.

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Autoclaved Leishmania major (ALM) along with BCG, presently undergoing phase II clinical trial by WHO for its vaccine potential against cutaneous leishmaniasis, has been successfully evaluated in single and triple dose schedules against L. donovani in Indian langurs (Presbytis entellus). Encouraged with the results, another formulation alum-precipitated ALM (provided by WHO) along with BCG has been evaluated in this system.

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Thymopentin and its analogs have been synthesized by the solution phase method of peptide synthesis and evaluated for their prophylactic efficacy against L. donovani infection in hamsters. Thymopentin and some of the analogs were found to stimulate nonspecific resistance of the host against Leishmania donovani infection in hamsters.

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We have previously reported that disease mimicking human visceral leishmaniasis can be established in Presbytis entellus, the Indian langur monkey, following a single intravenous challenge of 10(8) Leishmania donovani amastigotes. In the present report, infection was assessed in monkeys infected intravenously with a single dose of 10(8) amastigotes (HDA group), three weekly doses of 10(7) amastigotes (LDA group) and three weekly doses of 5 x 10(7) promastigotes (HDP group). Typical clinical infection was established in all three groups with significant parasite load.

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A number of alpha-cyano-beta-substituted ethyl propenoates were synthesised by condensation of appropriate aldehydes with ethyl cyanoacetate in basic medium. These compounds have been studied for their antileishmanial activities in vivo in hamsters. Two compounds exhibited 70-77% activities both by intramuscular and oral routes.

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Laboratory diagnosis of visceral leishmaniasis (VL) is usually based on the detection of Leishmania amastigotes in samples of bone marrow or splenic aspirate obtained by invasive procedures. Serological tests serve as a useful adjunct and are especially valuable in early or highly immune cases where amastigotes may be too scanty to be seen easily. The direct agglutination test (DAT) is generally considered the most suitable of the four types of tests currently employed (IFAT, counter immuno-electrophoresis, ELISA and DAT).

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The protective potential of killed Leishmania major (ALM) along with BCG was evaluated against L. donovani in Indian langur monkeys in single and triple dose schedules. A delayed protection was observed in monkeys after a single dose schedule of ALM (3 mg)+BCG (3 mg) given intradermally 2 months before intravenous challenge with L.

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Correlation between the degree of protection and induced serum antibody response in hamsters immunized with somatic and excretory-secretory (ES) antigens of adult. A. ceylanicum was investigated.

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Hepatocytes from bonet monkey (Macaca radiata) obtained by perfusion of a liver biopsy were infected in-vitro with Plasmodium cynomolgi bastianellii sporozoites raised in Anopheles stephensi. The development of exoerythrocytic (EE) stages was seen under phase contrast microscope and by Giemsa staining. Multinucleated EE-stages were seen in the cultured hepatocytes on day 7-8 post-sporozoite inoculation.

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Several novel type of lipopeptides were synthesized and evaluated for their ability to stimulate non-specific resistance against Leishmania donovani infection. Peritoneal macrophages isolated from young male hamsters treated with muramyl dipeptide (MDP) and various synthetic lipopeptides (6 mg/kg i.p.

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Methyl [5-[[4-(2-pyridinyl-1-piperazinyl] carbonyl]-1H- benzimidazol-2-yl] carbamate (CDRI Compound 81-470) exhibits a long prophylactic action against experimental ancylostomiasis, when given parenterally but not orally. To find out an explanation for such a behaviour, metabolic disposition studies were performed in hamsters using [3H] compound 81-470. Following intramuscular administration, the compound was found to form a depot at the site of injection and to remain there in substantial amount for more than 7 weeks.

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To delineate mechanisms involved in the prophylactic action of methyl [5-[[4-(2-pyridinyl)-1-piperazinyl]-carbonyl]-1H-benzimidazol-2 yl] carbamate (compound 81/470) in hamster against Ancylostoma ceylanicum infection, plasma level of the compound and status of reactive oxygen metabolites in jejunum at different periods of the drug treatment were examined. The compound was found to enhance the generation of both O2- and H2O2 by the jejunum possibly by activating xanthine oxidase. This stimulation was found to be both time and dose dependent.

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An immunological test based on indirect (plate) ELISA has been successfully standardized and modified using promastigote soluble antigen. The test carried out on 813 subjects from a kala-azar endemic area (including parasitologically confirmed patients, subjects presenting with clinical symptoms of visceral leishmaniasis and endemic controls) and a non-endemic area (with diseases other than kala-azar and apparently normal subjects) was found to detect, specifically, antileishmanial antibodies. The plate ELISA has been simplified to a more sensitive dot-ELISA where the results are read within 2-3 h.

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To understand the mechanism for the expulsion of Nippostrongylus brasiliensis from rats, age-dependent variations in the metabolism of reactive oxygen species in the parasite and the host intestines were examined. N. brasiliensis showed an age-dependent increase in its susceptibility to xanthine-xanthine oxidase and t-butyl hydroperoxide generated oxidants as well as to H2O2.

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Reproductive performances of female hamsters were investigated during Ancylostoma ceylanicum (hookworm) infection. Animals having the highest levels of infection (34.96 +/- 1.

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Three infection models namely an oncogenic virus Encephalomyocarditis (EMCV), a rodent strain of malaria, Plasmodium berghei, and a rodent hookworm parasite, Nippostrongylus brasiliensis, were used to confirm the in vivo immunotoxic potential of styrene reported in our previous communication. The altered host resistance to these challenge infections was evaluated in rodents pre-treated with 0, 0.02, 0.

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Impact of change of heteroatom in pentavalent heterocycles, viz., pyrroles, isoxazoles, imidazoles and crotonates on the profile of antileishmanial activity against amastigotes of L. donovani using in vivo test system and macrophage-amastigote culture system has been studied.

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Pathomorphological and immunological studies were carried out on rodents following oral administration of 0, 0.1, 0.25 and 0.

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