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- 저자 : Amit Kumar (검색결과 217 건)
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( Amit Kumar Chaudhary ),( Bijay Singh ),( Sushila Maharjan ),( Amit Kumar Jha ),( Byung Gee Kim ),( Jae Kyung Sohng ) 한국미생물 · 생명공학회 2014 Journal of microbiology and biotechnology Vol.24 No.8
Doxorubicin, produced by Streptomyces peucetius ATCC 27952, is tightly regulated by dnrO, dnrN, and dnrI regulators. Genome mining of S. peucetius revealed the presence of the IclR (doxR) type family of transcription regulator mediating the signal-dependent expression of operons at the nonribosomal peptide synthetase gene cluster. Overexpression of doxR in native strain strongly repressed the drug production. Furthermore, it also had a negative effect on the regulatory system of doxorubicin, wherein the transcript of dnrI was reduced to the maximum level in comparision with the other two. Interestingly, the overexpression of the same gene also had strong inhibitory effects on the production of actinorhodin (blue pigment) and undecylprodigiosin (red pigment) in Streptomyces coelicolor M145, herboxidiene production in Streptomyces chromofuscus ATCC 49982, and spinosyn production in Saccharopolyspora spinosa NRRL 18395, respectively. Moreover, DoxR exhibited pleiotropic effects on the production of blue and red pigments in S. coelicolor when grown in different agar media, wherein the production of blue pigment was inhibited in R2YE medium and the red pigment was inhibited in YEME medium. However, the production of both blue and red pigments from S. coelicolor harboring doxR was halted in ISP2 medium, whereas S. coelicolor produced both pigmented antibiotics in the same plate. These consequences demonstrate that the on and off production of these antibiotics was not due to salt stress or media compositions, but was selectively controlled in actinomycetes.
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An Empirical Approach for Estimation of the Software Development Effort
Amit Kumar Jakhar,Kumar Rajnish 보안공학연구지원센터 2015 International Journal of Multimedia and Ubiquitous Vol.10 No.2
The number of standards and methods has been developed for software estimation in the last many decades. These methods help practitioners and engineers to estimate the effort accurately, but they found their inability to estimate software precisely. In this paper, an empirical approach is developed to measure the software development effort. The well-known PROMISE data sets of 217 projects are collected and the several performance factors are used in this paper to validate the estimated results. This work also considers the most popular model for software effort estimating, i.e. COCOMO. And the result of the COCOMO model and proposed an empirical approach is compared with the actual effort, and concludes that the proposed approach estimates the software development effort better than COCOMO in several aspects.
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Association between Beta Adrenergic Receptor Polymorphism and Ischemic Stroke: A Meta-Analysis
Amit Kumar,Manya Prasad,Pradeep Kumar,Arun Kumar Yadav,Awadh Kishor Pandit,Prachi Kathuria 대한뇌졸중학회 2015 Journal of stroke Vol.17 No.2
Background and Purpose The purpose of this meta-analysis was to determine the precise association between beta-2 adrenergic receptor (β2AR) polymorphism and Ischemic stroke. Methods Published case control studies on association between β2AR and ischemic stroke were searched from electronic databases. Pooled Odds ratio and 95% Confidence interval were calculated by using software RevMan version 5.2. Results A total of three studies involving 1,642 cases and 1,673 controls, which were published from 2007 to 2014, were subjected to meta-analysis for allelic association and 518 cases and 510 controls for genotypic association. Pooled analysis of two studies for genotypic association suggested that subjects carrying Gln27Glu polymorphism of β2AR had an increased risk for Ischemic stroke under recessive model (OR 2.09; 95% CI; 1.20 to 3.64) and under dominant model (OR 1.47; 95% CI 1.14 to 1.90). Pooled analysis of three studies for allelic association showed a significantly higher Glu27 allele of β2AR in the patients with ischemic stroke (OR 1.58; 95% CI; 1.38 to 1.81). Conclusions The present meta-analysis suggests that Gln27Glu polymorphism of β2AR gene is associated with increased risk for ischemic stroke.
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Predictive Breast Cancer Statistical Modelling for Early Diagnosis
Amit Kumar Gupta,Ankit Verma,Vipin Kumar,Nikhil Kumar,Dowon Kim,Young-Jin Jung,Mangal Sain 한국자기학회 2023 Journal of Magnetics Vol.28 No.4
Breast cancer is a significant global health concern, stressing the urgent need for early detection. Early diagnosis improves access to varied treatments and significantly enhances patient outcomes. This study explores breast cancer detection over two days, aiming to create a precise and efficient machine learning model. The research uses a diverse dataset, combining clinical, genetic, and imaging data, including magnetic resonance imaging (MRI), X-ray, and electromagnetic data. Rigorous data preprocessing, including variable normalization and feature identification, enhances dataset quality. Predictive models use statistical techniques like logistic regression, decision trees, and random forest. Key metrics, such as accuracy, precision, recall, and area under the curve (AUC), assess model efficacy. Results reveal high accuracy and AUC scores, indicating potential for precise breast cancer detection. The study enhances our understanding of breast cancer dynamics, showcasing the effectiveness of machine learning for accurate and efficient early diagnosis. The research underscores diverse datasets and careful statistical modeling as crucial for predictive breast cancer capabilities.
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Amit Kumar Jha,Anaya Raj Pokhrel,Amit Kumar Chaudhary,Seong-Whan Park,Wan Je Cho,송재경 한국분자세포생물학회 2014 Molecules and cells Vol.37 No.10
Spinosyns A and D are potent ingredient for insect control with exceptional safety to non-target organisms. It consists of a 21-carbon tetracyclic lactone with forosamine and tri-O-methylated rhamnose which are derived from S-adenosyl-methionine. Although previous studies have revealed the involvement of metK1 (S-adenosylmethionine synthetase), rmbA (glucose-1-phosphate thymidylyltransferase), and rmbB (TDP-D-glucose-4, 6-dehydratase) in the biosynthesis of spinosad, expression of these genes into rational screened Saccharopolyspora spinosa (S. spinosa MUV) has not been elucidated till date. In the present study, S. spinosa MUV was developed to utilize for metabolic engineering. The yield of spinosyns A and D in S. spinosa MUV was 244 mg L-1 and 129 mg L-1, which was 4.88-fold and 4.77-fold higher than that in the wild-type (50 mg L-1 and 27 mg L-1), respectively. To achieve the better production; positive regulator metK1-sp, rmbA and rmbB genes from Streptomyces peucetius, were expressed and co-expressed in S. spinosa MUV under the control of strong ermE* promoter, using an integration vector pSET152 and expression vector pIBR25, respectively. Herewith, the genetically engineered strain of S. spinosa MUV, produce spinosyns A and D up to 372/217 mg L-1 that is 7.44/8.03-fold greater than that of wild type. This result demonstrates the use of metabolic engineering on rationally developed high producing natural variants for the production.
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Amit Kumar Singh,Bishnu Prasad Panda,Smita Mohanty,Sanjay Kumar Nayak,Manoj Kumar Gupta 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.11
The current study reports the effect of low viscous aliphatic reactive diluent (RD), MWCNT and VGCF on the curing kinetics of amine cured epoxy adhesive system employing non-isothermal differential scanning calorimetric (DSC) technique. Non-isothermal DSC thermograms of epoxy adhesive were studied at various heating rates: 5, 10 and 15 oC/min. The decrease in the exothermic peak height with the introduction of MWCNTs and VGCFs was taken as proof of the acceleration effect of nano-fillers on the epoxy-amine curing reaction. Also, increased Tonset, TP and ΔHcurs values were observed for epoxy/RD adhesive system at all heating rates. The value of activation energy (Ea) was determined using Kissinger and Flynn-Wall-Ozawa methods. Experimental results showed that the addition of 10 wt% RD increased the Ea from 60 to 63 kJ/mol on account of the reduced viscosity, allowing better contact of resin with the curing agent. Furthermore, MWCNTs have an accelerating effect on the cure kinetics that does not change the autocatalytic cure reaction mechanism of epoxy resin. It was also found that the addition of MWCNT and VGCF decreases the overall degree of conversion, as evident with lower ΔHcure and Ea of the cured adhesive when compared with epoxy/RD system. The dependency of Ea on degree of conversion ranging from α =0.1 to 0.9was also investigated. The two normalized functions y(α) and z(α) were also considered in order to study the complex curing mechanism. The kinetic parameters m, n and lnA were obtained by using two parameter autocatalytic Sestak-Berggren model. The curves revealed good agreement between experimentally determined and theoretically obtained MWCNT/VGCF reinforced epoxy adhesive systems.
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Jha, Amit Kumar,Pokhrel, Anaya Raj,Chaudhary, Amit Kumar,Park, Seong-Whan,Cho, Wan Je,Sohng, Jae Kyung Korean Society for Molecular and Cellular Biology 2014 Molecules and cells Vol.37 No.10
Spinosyns A and D are potent ingredient for insect control with exceptional safety to non-target organisms. It consists of a 21-carbon tetracyclic lactone with forosamine and tri-Omethylated rhamnose which are derived from S-adenosyl-methionine. Although previous studies have revealed the involvement of metK1 (S-adenosylmethionine synthetase), rmbA (glucose-1-phosphate thymidylyltransferase), and rmbB (TDP-D-glucose-4, 6-dehydratase) in the biosynthesis of spinosad, expression of these genes into rational screened Saccharopolyspora spinosa (S. spinosa MUV) has not been elucidated till date. In the present study, S. spinosa MUV was developed to utilize for metabolic engineering. The yield of spinosyns A and D in S. spinosa MUV was $244mgL^{-1}$ and $129mgL^{-1}$, which was 4.88-fold and 4.77-fold higher than that in the wild-type ($50mgL^{-1}$ and $27mgL^{-1}$), respectively. To achieve the better production; positive regulator metK1-sp, rmbA and rmbB genes from Streptomyces peucetius, were expressed and co-expressed in S. spinosa MUV under the control of strong $ermE^*$ promoter, using an integration vector pSET152 and expression vector pIBR25, respectively. Here-with, the genetically engineered strain of S. spinosa MUV, produce spinosyns A and D up to $372/217mgL^{-1}$ that is 7.44/8.03-fold greater than that of wild type. This result demonstrates the use of metabolic engineering on rationally developed high producing natural variants for the production.
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Sharma, Amit Kumar,Bhushan, Bharat,Kumar, Sanjeev,Kumar, Pushpendra,Sharma, Arjava,Kumar, Satish Asian Australasian Association of Animal Productio 2004 Animal Bioscience Vol.17 No.9
Random amplification of polymorphic DNA-Polymerase Chain Reaction (RAPD-PCR) analysis was carried out using DNA samples of 30 animals of Rathi cattle and 42 animals of Tharparkar cattle. Genomic DNA was isolated as per standard protocol and evaluated for its quality, purity and concentration. Twenty three random primers were screened out of which 15 primers yielded satisfactory amplifications and were used for further analysis. Average numbers of polymorphic fragments per primer were 7.07${\pm}$0.86 in Rathi and 6.80${\pm}$0.61 in Tharparkar cattle. The percentage of polymorphic bands in these two cattle breeds were 86 and 87%, respectively. Within breed genetic similarities for pooled over primers in the animals of Rathi and Tharparkar breeds were .577${\pm}$0.30 and 0.531${\pm}$0.02, respectively on the basis of band frequency (BF) and 0.645${\pm}$0.04 and 0.534${\pm}$0.04, respectively on the basis of band sharing (BS). Averages of between breed genetic similarities for pooled over primers were 0.97 and 0.92 according to BF and BS, respectively, which reflect higher degree of genetic similarity between Rathi and Tharparkar cattle breeds. Index of genetic distance based on BF and BS for pooled over primers was 0.030${\pm}$0.011 and 0.088${\pm}$0.031, respectively. Percentage of polymorphic bands and within-breed genetic similarities on the basis of band frequency (BF) and band sharing (BS) for pooled over primers revealed higher genetic similarity in Rathi than Tharparkar cattle population. High estimates of between breed genetic similarities for pooled over primers indicated that either Rathi is having decent from Tharparkar or both the cattle breeds are having common descent. Low value of Index of genetic distances between these two cattle breeds may be due to the fact that Rathi and Tharparkar cattle breeds are the native of Thar Desert in Northwest India. The results of between breed genetic distances also confirm the existence of high degree of genetic similarity between these two breeds of cattle.
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Oxidative Stress and Antioxidants in Disease and Cancer: A Review
Gupta, Rakesh Kumar,Patel, Amit Kumar,Shah, Niranjan,Choudhary, Arun Kumar,Jha, Uday Kant,Yadav, Uday Chandra,Gupta, Pavan Kumar,Pakuwal, Uttam Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.11
Reactive oxygen species (ROS), highly reactive molecules, are produced by living organisms as a result of normal cellular metabolism and environmental factors, and can damage nucleic acids and proteins, thereby altering their functions. The human body has several mechanisms to counteract oxidative stress by producing antioxidants. A shift in the balance between oxidants and antioxidants in favor of oxidants is termed as "oxidative stress". Paradoxically, there is a large body of research demonstrating the general effect of oxidative stress on signaling pathways, less is known about the initial and direct regulation of signaling molecules by ROS, or what we term the "oxidative interface." This review focuses on the molecular mechanisms through which ROS directly interact with critical signaling molecules to initiate signaling in a broad variety of cellular processes, such as proliferation and survival (MAP kinases and PI3 kinase), ROS homeostasis, and antioxidant gene regulation (Ref-1 and Nrf-2). This review also deals with classification as well as mechanisms of formation of free radicals, examining their beneficial and deleterious effects on cellular activities and focusing on the potential role of antioxidants in preventing and repairing damage caused by oxidative stress. A discussion of the role of phytochemical antioxidants in oxidative stress, disease and the epigenome is included.
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