135 research outputs found

    Analysis of Extended Threshold Wavelength Photoresponse in Nonsymmetrical p-GaAs/AlGaAs Heterostructure Photodetectors

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    We analyze the extended threshold wavelength photoresponse beyond the standard threshold limit (λt = 1.24/Δ, where Δ is the activation energy) in nonsymmetrical pGaAs/AlGaAs heterostructure photodetectors with a barrier energy offset. We propose that hot-cold hole carrier interactions in the p-GaAs absorber are responsible for the threshold wavelength extension. Experimental results are analyzed by considering a quasi-Fermi distribution of hot holes at a hot hole temperature (TH), which is much higher than the lattice temperature (TL). The experimental photoresponse is fitted using an escape cone model, modified with a quasi-Fermi level (EquasiF). The simulated results are found to be in good agreement with experimental data, justifying the model used

    Assessment of oceanic tuna and allied fish resources of the Indian exclusive economic zone based on exploratory surveys

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    The present paper overview the results of survey on marine resources of the Indian EEZ including tuna and eillied fish species, their distribution, catch rates, seasonality, assessment of stocks etc. supplemented by the chartered vessels' data. The paper also presents the trends in the tuna fishing and future survey programme of the Fishery Survey of India

    Boosting Principal Component Analysis by Genetic Algorithm

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    This paper presents a new method of feature extraction by combining principal component analysis and genetic algorithm. Use of multiple pre-processors in combination with principal component analysis generates alternate feature spaces for data representation. The present method works out the fusion of these multiple spaces to create higher dimensionality feature vectors. The fused feature vectors are given chromosome representation by taking feature components to be genes. Then these feature vectors are allowed to undergo genetic evolution individually. For genetic algorithm, initial population is created by calculating probability distance matrix, and by applying a probability distance metric such that all the genes which lie farther than a defined threshold are tripped to zero. The genetic evolution of fused feature vector brings out most significant feature components (genes) as survivours. A measure of significance is adapted on the basis of frequency of occurrence of the surviving genes in the current population. Finally, the feature vector is obtained by weighting the original feature components in proportion to their significance. The present algorithm is validated in combination with a neural network classifier based on error backpropagation algorithm, and by analysing a number of benchmark datasets available in the open sources.Defence Science Journal, 2010, 60(4), pp.392-398, DOI:http://dx.doi.org/10.14429/dsj.60.49

    Pan-Cancer Analysis of lncRNA Regulation Supports Their Targeting of Cancer Genes in Each Tumor Context

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    Long noncoding RNAs (lncRNAs) are commonly dys-regulated in tumors, but only a handful are known toplay pathophysiological roles in cancer. We inferredlncRNAs that dysregulate cancer pathways, onco-genes, and tumor suppressors (cancer genes) bymodeling their effects on the activity of transcriptionfactors, RNA-binding proteins, and microRNAs in5,185 TCGA tumors and 1,019 ENCODE assays.Our predictions included hundreds of candidateonco- and tumor-suppressor lncRNAs (cancerlncRNAs) whose somatic alterations account for thedysregulation of dozens of cancer genes and path-ways in each of 14 tumor contexts. To demonstrateproof of concept, we showed that perturbations tar-geting OIP5-AS1 (an inferred tumor suppressor) andTUG1 and WT1-AS (inferred onco-lncRNAs) dysre-gulated cancer genes and altered proliferation ofbreast and gynecologic cancer cells. Our analysis in-dicates that, although most lncRNAs are dysregu-lated in a tumor-specific manner, some, includingOIP5-AS1, TUG1, NEAT1, MEG3, and TSIX, synergis-tically dysregulate cancer pathways in multiple tumorcontexts

    Formulation and evaluation of Niosomal cream from moringa leaf extract for enhanced Antifungal Activity

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    Niosomal drug delivery systems have gained attention for enhancing the bioavailability and efficacy of pharmaceutical formulations. This study explores the formulation and evaluation of a niosomal antifungal cream incorporating Moringa oleifera leaf extract. Moringa leaves contain bioactive compounds with antifungal properties, making them a potential alternative to synthetic antifungal agents. Niosomes, as vesicular carriers, improve drug stability, penetration, and controlled release, enhancing therapeutic effects. The formulated cream was characterized for particle size, entrapment efficiency, pH, spreadability, and in vitro antifungal activity against common fungal strains. The results demonstrated that the niosomal formulation improved drug retention and prolonged antifungal activity compared to conventional creams. The study suggests that a niosomal antifungal cream containing Moringa leaf extract could be an effective natural treatment for fungal infections, offering a promising alternative to conventional antifungal therapies. Keywords: Moringa oleifera, niosomal cream, antifungal activity, drug delivery, dermatophytosis, Candida albicans, vesicular dru

    A transcriptomic snapshot of early molecular communication between Pasteuria penetrans and Meloidogyne incognita

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    © The Author(s). 2018Background: Southern root-knot nematode Meloidogyne incognita (Kofoid and White, 1919), Chitwood, 1949 is a key pest of agricultural crops. Pasteuria penetrans is a hyperparasitic bacterium capable of suppressing the nematode reproduction, and represents a typical coevolved pathogen-hyperparasite system. Attachment of Pasteuria endospores to the cuticle of second-stage nematode juveniles is the first and pivotal step in the bacterial infection. RNA-Seq was used to understand the early transcriptional response of the root-knot nematode at 8 h post Pasteuria endospore attachment. Results: A total of 52,485 transcripts were assembled from the high quality (HQ) reads, out of which 582 transcripts were found differentially expressed in the Pasteuria endospore encumbered J2 s, of which 229 were up-regulated and 353 were down-regulated. Pasteuria infection caused a suppression of the protein synthesis machinery of the nematode. Several of the differentially expressed transcripts were putatively involved in nematode innate immunity, signaling, stress responses, endospore attachment process and post-attachment behavioral modification of the juveniles. The expression profiles of fifteen selected transcripts were validated to be true by the qRT PCR. RNAi based silencing of transcripts coding for fructose bisphosphate aldolase and glucosyl transferase caused a reduction in endospore attachment as compared to the controls, whereas, silencing of aspartic protease and ubiquitin coding transcripts resulted in higher incidence of endospore attachment on the nematode cuticle. Conclusions: Here we provide evidence of an early transcriptional response by the nematode upon infection by Pasteuria prior to root invasion. We found that adhesion of Pasteuria endospores to the cuticle induced a down-regulated protein response in the nematode. In addition, we show that fructose bisphosphate aldolase, glucosyl transferase, aspartic protease and ubiquitin coding transcripts are involved in modulating the endospore attachment on the nematode cuticle. Our results add new and significant information to the existing knowledge on early molecular interaction between M. incognita and P. penetrans.Peer reviewedFinal Published versio

    Pathological studies on Pteris cretica (L.) fern-Bovine Papilloma Virus infection in Syrian Golden Hamsters (Mesocricetus auratus)

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    Pteris cretica (L.) commonly known as Cretan brake is widely distributed in nature and considered as potential environmental carcinogen. However, only limited literature is available on this fern commonly taken by cattle while grazing. It is known that in cattle Bovine papilloma virus (BPV) induced benign tumours are converted into malignant with interaction of ptaquiloside (Pta) present in ferns. In the present investigation, we evaluated the pathological effects of P. cretica (PC)-BPV infection in laboratory model hamster. Though toxic principle Pta was detected in fern samples but quercetin could not be found. Tumours were successfully induced in hamsters by cutaneous wart suspension and histopathologically diagnosed as fibroma and lipofibroma. Histopathologically, hamsters showed mild to moderate vascular changes in vital organs, multiple cysts, degenerative changes, bile duct hyperplasia and necrosis in liver, haemorrhages and haemosiderosis in spleen, hypersecretory activity and prominent Peyer’s patches in ileum, degenerative changes and presence of eosinophilic casts in renal tubules. Ultrastructural study revealed apoptosis in hepatocytes, abundance of variable shaped mitochondria in renal tubular lining epithelial cells and enterocytes showed abundance of mitochondria and cytoplasmolysis in the fern fed groups. Almost all the hamsters from BPV, fern and virus infection (PC+BPV) groups developed similar type of tumorous growths. The visible growths in the hamsters of these groups were either single or double large sized except multiple tumorous growths in one hamster from PC+BPV group. However, multiple palpable subcutaneous nodules were developed at the site of scarification in all the hamsters of BPV and PC+BPV groups. Our findings suggest that the Pta containing P. cretica feeding induced hepatotoxic and nephrotoxic lesions in hamsters, but effects of P. cretica-BPV infection were found negligible

    Analysis of Barrier Parameters on the Extended Threshold Wavelength of Infrared Detectors

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    The threshold wavelength (λt) of spectral photoresponse of any semiconductor photodetector is determined by the minimum energy gap (Δ=1.24/λt) of the material, or the interfacial energy gap of the heterostructure. It was shown before that the threshold limit can be extended beyond λt to obtain an extended threshold wavelength λeff(λeff≫λt) in detectors with a barrier energy offset (δEv) and a gradient. Here, in this letter, we analyze the effect of barrier parameters such as δEv and gradient on the extended threshold wavelength of infrared detectors for the temperature range up to 50 K

    Insect pathogens as biological control agents: back to the future

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    The development and use of entomopathogens as classical, conservation and augmentative biological control agents have included a number of successes and some setbacks in the past 15 years. In this forum paper we present current information on development, use and future directions of insect-specific viruses, bacteria, fungi and nematodes as components of integrated pest management strategies for control of arthropod pests of crops, forests, urban habitats, and insects of medical and veterinary importance. Insect pathogenic viruses are a fruitful source of MCAs, particularly for the control of lepidopteran pests. Most research is focused on the baculoviruses, important pathogens of some globally important pests for which control has become difficult due to either pesticide resistance or pressure to reduce pesticide residues. Baculoviruses are accepted as safe, readily mass produced, highly pathogenic and easily formulated and applied control agents. New baculovirus products are appearing in many countries and gaining an increased market share. However, the absence of a practical in vitro mass production system, generally higher production costs, limited post application persistence, slow rate of kill and high host specificity currently contribute to restricted use in pest control. Overcoming these limitations are key research areas for which progress could open up use of insect viruses to much larger markets. A small number of entomopathogenic bacteria have been commercially developed for control of insect pests. These include several Bacillus thuringiensis sub-species, Lysinibacillus (Bacillus) sphaericus, Paenibacillus spp. and Serratia entomophila. B. thuringiensis sub-species kurstaki is the most widely used for control of pest insects of crops and forests, and B. thuringiensis sub-species israelensis and L. sphaericus are the primary pathogens used for medically important pests including dipteran vectors,. These pathogens combine the advantages of chemical pesticides and microbial control agents (MCAs): they are fast acting, easy to produce at a relatively low cost, easy to formulate, have a long shelf life and allow delivery using conventional application equipment and systemics (i.e. in transgenic plants). Unlike broad spectrum chemical pesticides, B. thuringiensis toxins are selective and negative environmental impact is very limited. Of the several commercially produced MCAs, B. thuringiensis (Bt) has more than 50% of market share. Extensive research, particularly on the molecular mode of action of Bt toxins, has been conducted over the past two decades. The Bt genes used in insect-resistant transgenic crops belong to the Cry and vegetative insecticidal protein families of toxins. Bt has been highly efficacious in pest management of corn and cotton, drastically reducing the amount of broad spectrum chemical insecticides used while being safe for consumers and non-target organisms. Despite successes, the adoption of Bt crops has not been without controversy. Although there is a lack of scientific evidence regarding their detrimental effects, this controversy has created the widespread perception in some quarters that Bt crops are dangerous for the environment. In addition to discovery of more efficacious isolates and toxins, an increase in the use of Bt products and transgenes will rely on innovations in formulation, better delivery systems and ultimately, wider public acceptance of transgenic plants expressing insect-specific Bt toxins. Fungi are ubiquitous natural entomopathogens that often cause epizootics in host insects and possess many desirable traits that favor their development as MCAs. Presently, commercialized microbial pesticides based on entomopathogenic fungi largely occupy niche markets. A variety of molecular tools and technologies have recently allowed reclassification of numerous species based on phylogeny, as well as matching anamorphs (asexual forms) and teleomorphs (sexual forms) of several entomopathogenic taxa in the Phylum Ascomycota. Although these fungi have been traditionally regarded exclusively as pathogens of arthropods, recent studies have demonstrated that they occupy a great diversity of ecological niches. Entomopathogenic fungi are now known to be plant endophytes, plant disease antagonists, rhizosphere colonizers, and plant growth promoters. These newly understood attributes provide possibilities to use fungi in multiple roles. In addition to arthropod pest control, some fungal species could simultaneously suppress plant pathogens and plant parasitic nematodes as well as promote plant growth. A greater understanding of fungal ecology is needed to define their roles in nature and evaluate their limitations in biological control. More efficient mass production, formulation and delivery systems must be devised to supply an ever increasing market. More testing under field conditions is required to identify effects of biotic and abiotic factors on efficacy and persistence. Lastly, greater attention must be paid to their use within integrated pest management programs; in particular, strategies that incorporate fungi in combination with arthropod predators and parasitoids need to be defined to ensure compatibility and maximize efficacy. Entomopathogenic nematodes (EPNs) in the genera Steinernema and Heterorhabditis are potent MCAs. Substantial progress in research and application of EPNs has been made in the past decade. The number of target pests shown to be susceptible to EPNs has continued to increase. Advancements in this regard primarily have been made in soil habitats where EPNs are shielded from environmental extremes, but progress has also been made in use of nematodes in above-ground habitats owing to the development of improved protective formulations. Progress has also resulted from advancements in nematode production technology using both in vivo and in vitro systems; novel application methods such as distribution of infected host cadavers; and nematode strain improvement via enhancement and stabilization of beneficial traits. Innovative research has also yielded insights into the fundamentals of EPN biology including major advances in genomics, nematode-bacterial symbiont interactions, ecological relationships, and foraging behavior. Additional research is needed to leverage these basic findings toward direct improvements in microbial control

    Structure Based Design and Synthesis of Peptide Inhibitor of Human LOX-12: In Vitro and In Vivo Analysis of a Novel Therapeutic Agent for Breast Cancer

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    Human breast cancer cell proliferation involves a complex interaction between growth factors, steroid hormones and peptide hormones. The interaction of growth factors, such as epidermal growth factor (EGF), with their receptors on breast cancer cells can lead to the hydrolysis of phospholipids and release of fatty acid such as arachidonic acid, which can be further metabolized by cyclooxygenase (COX) and lipoxygenase (LOX) pathways to produce prostaglandins. The high concentration of prostaglandins has been associated with chronic inflammatory diseases and several types of human cancers. This is due to the over expression COX, LOX and other inflammatory enzymes. Ten peptides were designed and synthesized by solid phase peptide synthesis and analyzed in vitro for enzyme inhibition. Out of these peptides, YWCS had shown significant inhibitory effects. The dissociation constant (KD) was determined by surface plasmon resonance (SPR) analysis and was found to be 3.39×10−8 M and 8.6×10−8 M for YWCS and baicalein (positive control), respectively. The kinetic constant Ki was 72.45×10−7 M as determined by kinetic assay. The peptide significantly reduced the cell viability of estrogen positive MCF-7 and estrogen negative MDA-MB-231 cell line with the half maximal concentration (IC50) of 75 µM and 400 µM, respectively. The peptide also induced 49.8% and 20.8% apoptosis in breast cancer cells MCF-7 and MDA-MB-231, respectively. The YWCS was also found to be least hemolytic at a concentration of 358 µM. In vivo studies had shown that the peptide significantly inhibits tumor growth in mice (p<0.017). This peptide can be used as a lead compound and complement for ongoing efforts to develop differentiation therapies for breast cancer
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