107 research outputs found

    Neka svojstva (2 + 1)–dimenzijske KdV jednadžbe sa smetnjom

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    Explicit solitary-wave solutions of the (2 + 1)-dimensional perturbed KdV equation obtained by Ma et al. are obtained by using the Backlund transformation. Next, we obtain the two-soliton solution in a form which implies a form of superposition. Lastly, the corresponding modified equations are obtained by a new form of the Miura map.Primjenom Backlundove transformacije dobili smo eksplicitna rješenja (2 + 1)– dimenzijske KdV jednadžbe sa smetnjom koju su izveli Ma i sur. Zatim izvodimo dvosolitonska rješenja u obliku koji podrazumijeva dodavanje rješenja. Konačno, odgovarajuće promijenjene jednadžbe izvodimo novim vidom Miurinog preslikavanja

    Neka svojstva (2 + 1)–dimenzijske KdV jednadžbe sa smetnjom

    Get PDF
    Explicit solitary-wave solutions of the (2 + 1)-dimensional perturbed KdV equation obtained by Ma et al. are obtained by using the Backlund transformation. Next, we obtain the two-soliton solution in a form which implies a form of superposition. Lastly, the corresponding modified equations are obtained by a new form of the Miura map.Primjenom Backlundove transformacije dobili smo eksplicitna rješenja (2 + 1)– dimenzijske KdV jednadžbe sa smetnjom koju su izveli Ma i sur. Zatim izvodimo dvosolitonska rješenja u obliku koji podrazumijeva dodavanje rješenja. Konačno, odgovarajuće promijenjene jednadžbe izvodimo novim vidom Miurinog preslikavanja

    Phytol-Derived Novel Isoprenoid Immunostimulants

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    This review describes the adjuvanticity of novel diterpenoids (synthetic phytol derivatives) compared to some commercially available adjuvants. The efficacy of the phytol-derived immunostimulants was evaluated in terms of their ability to activate innate immunity, amplify various antigen-specific immune responses, and engender immunological memory with no discernible adverse effects in both competent and immune-deficient mice. The profile that emerges out of these studies reveals that the phytol derivatives are excellent immunostimulants, superior to a number of commercial adjuvants in terms of long-term memory induction and activation of both innate and acquired immunity. Additionally, the phytol-derived compounds have no cumulative inflammatory or toxic effects even in immuno-compromised mice

    Natural pesticides for pest control in agricultural crops: an alternative and eco-friendly method

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    Biological pesticides are pesticides derived from natural materials such as bacteria, plants, and minerals that are applied to crops to kill pests. Biopesticides are targeted, inexpensive, eco-friendly, sustainable, leave no trace, and are not associated with the production of greenhouse gases. It contributes significantly to the agricultural bio-economy's sustainability. The advantages to the ecosystem provided by many significant biological resources justify the incorporation of biopesticides in Integrated Pest Management (IPM) programs. Through advancements in research and development, the use of biopesticides has significantly reduced environmental contamination. The development of biopesticides promotes agricultural modernization and will surely result in a gradual phase-out of chemical pesticides. Although synthetic pesticides have positive effects on crop yield and productivity, they also have some negative impacts on soil biodiversity, animals, aquatic life, and humans. In general, synthetic pesticides make the soil brittle, decrease soil respiration, and reduce the activity of some soil microorganisms, such as earthworms. Pesticide buildup in bodies of water can spread from aquatic life to animals including people, as their biomagnification can cause fatal diseases like cancer, kidney disease, rashes on the skin, diabetes, etc. Biopesticides, on the other hand, have surfaced and have proven to be quite beneficial in the management of pests and are safe for the environment and hence have emerged as very useful in the control of pests with a lot of merits.  The present review provides a broad perspective on the different kinds of pesticides. We analyzed suitable and environmentally friendly ways to improve the acceptance and industrial application of microbial herbicides, phytopesticides, and nano biopesticides for plant nutrition, crop protection/yield, animal/human health promotion, as well as their potential integration into the integrated pest management system

    Plant growth promotion and antifungal activities of the mango phyllosphere bacterial consortium for the management of Fusarium wilt disease in pea (Pisum sativum L.)

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    Root rot caused by the pathogen Fusarium oxysporum is the number one cause of pea plant (P. sativum L.) death. There are many potential advantages to using rhizobacteria, endophytic bacteria and phyllospheric bacteria for managing plant diseases and promoting plant growth. This study investigated the potentiality of consortium species of bacteria to suppress root rot disease and their ability to promote the growth of pea plants compared with their individual and control plants. A total of 55 phyllospheric bacteria were isolated from mango flower and Bacillus sp. LBF- 02, Bacillus sp. LBF- 03 and Bacillus sp. LBF- 05 showed the most potent antimicrobial activity against root rot pathogens in a dual culture assay. Identification of phyllobacterial strain LBF- 01, LBF- 03 and LBF-05 were done by 16S rDNA sequence analysis using 704f forward primer (50-AGATTTTCCGACGGCAGGTT-30) and 907r reverse primer (50-CCGTCAATTCMTTTRAGTTT-30) with the PCR conditions. Their ability to solubilize phosphate, produce ammonia, siderophore and indole acetic acid, as well as produce extracellular enzymes in vitro was excellent. The results of a greenhouse study found that pea seed treated with consortium isolate significantly increased high germination rates and vigour indexes, as well as shoot and root length, fresh and dry weights, as compared with seed treated with single isolate and control. The defense enzyme activities in consortium treated pots were higher than those in individual and control pots. The plants treated with consortium exhibited higher levels of chlorophyll and carotenoids content in their leaves compared to the untreated control and single treated plants. A significant variation in the chemical profile of pea plants was found (F7,16 ? 2.598; P ? 0.048) resulting from different treatments (T1-T8). After evaluating a variety of growth and microbiological parameters, it was concluded that inoculation with the microbial consortium contributed to raising healthy and vigorously growing pea seedlings in greenhouse conditions, which is applicable in the field in future for sustainable farming

    ASSESSMENT OF SECONDARY METABOLITES WITH RELATION TO THEIR ANTIOXIDANT ACTIVITY OF FUNGAL ENDOPHYTES ISOLATED FROM MEDICINAL PLANTS

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    Objective: The detection of fungal endophytes and assessment of their antioxidant activity isolated from two medicinally important plants, Calotropis procera (L.) R. Br. and Catharanthus roseus (L.) G. Don. from parts of Burdwan district of West Bengal, India.Methods: Isolation of fungal endophytes was carried out following the standard methods in potato dextrose agar (PDA) media. Identification, determination of colonization frequency, fermentation and extraction was done as stated in the standard protocol. Qualitative assay of the bioactive compound has investigated by standard protocol specifically for them. Quantitative estimation of total phenol was done by spectrophotometric method using gallic acid as standard. The antioxidant activity of the cell-free extract was determined by phosphomolybdenum assay and 2, 2-diphenyl-1-picrylhydrazyl (DPPH) scavenging method.Results: Three dominant endophytic fungi each from C. procera and C. roseus with high colonization frequency in Penicillium singorense 25% and Alternaria alternata 21.87 % respectively has isolated and identified. Qualitative detection of secondary metabolites revealed that Penicillium singorense isolated from both plants and Aspergillus neoflaviceps (from C. procera) were found to be able to produce all the functional metabolites so far tested. It is evident that highest phenol 27.65±1.2 mg/g and flavonoid 2.06±0.1 mg/g content was shown by Curvularia geniculata. Highest antioxidant activity was exhibited by C. geniculata in both phosphomolybdenum assay i.e., total antioxidant capacity 2.46±0.11 and % inhibition of DPPH radical 94.55±0.015%.Conclusion: Present study, therefore highlights the growing concept that the bioactive compounds produced by the endophytes not only established host endophyte relationship but also have an immense chance of an application in the field of medicine, agriculture and industry

    Turbine blade failure in a thermal power plant

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    The failure of a LP (low pressure) turbine blade of a 220 MW thermal power plant is presented. The blade was made of martensitic stainless steel and the structure was tempered martensite. There was no evidence of degradation of blade material. The fracture took place at the aerofoil region, 113-mm from the root. Throughout the blade surface Si rich phases were detected. Several pits/grooves were found on the edges of the blades and chloride was detected in these pits. These were responsible for the crevice type corrosion. The probable carriers of Cl− were Ca and K, which were found on the blade. The failure mode was intergranular type. Possibly the ultimate failure was due to corrosion-fatigue

    Failure analysis of high temperature studs

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    Studs in the interceptor valve of a 110 MW unit failed after a service life of 148,700 h. The studs were operated under a steam pressure of 35 kg/cm2 and a temperature of 535°C. The studs were fractured at one end of the threaded end. Various techniques were employed to analyse the failure of the studs. It has been concluded that the failure of the studs was due to reverse temper embrittlement. The failure was delayed due to the presence of Mo and V. To reduce the tendency to this kind of failure, the following steps were recommended: (a) reduce the phosphorus content in the steel to a low level or (b) reduce the grain size to about 10 μm

    Quadruplex-single nucleotide polymorphisms (Quad-SNP) influence gene expression difference among individuals

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    Non-canonical guanine quadruplex structures are not only predominant but also conserved among bacterial and mammalian promoters. Moreover recent findings directly implicate quadruplex structures in transcription. These argue for an intrinsic role of the structural motif and thereby posit that single nucleotide polymorphisms (SNP) that compromise the quadruplex architecture could influence function. To test this, we analysed SNPs within quadruplex motifs (Quad-SNP) and gene expression in 270 individuals across four populations (HapMap) representing more than 14 500 genotypes. Findings reveal significant association between quadruplex-SNPs and expression of the corresponding gene in individuals (P < 0.0001). Furthermore, analysis of Quad-SNPs obtained from population-scale sequencing of 1000 human genomes showed relative selection bias against alteration of the structural motif. To directly test the quadruplex-SNP-transcription connection, we constructed a reporter system using the RPS3 promoter—remarkable difference in promoter activity in the ‘quadruplex-destabilized’ versus ‘quadruplex-intact’ promoter was noticed. As a further test, we incorporated a quadruplex motif or its disrupted counterpart within a synthetic promoter reporter construct. The quadruplex motif, and not the disrupted-motif, enhanced transcription in human cell lines of different origin. Together, these findings build direct support for quadruplex-mediated transcription and suggest quadruplex-SNPs may play significant role in mechanistically understanding variations in gene expression among individuals
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