Necessity of step-stress accelerated life testing experiment at higher steps

Chandra, N.,Khan, Mashroor Ahmad,Pandey, M. The Korean Reliability Society 2014 International Journal of Reliability and Applicati Vol.15 No.2

Accelerated life testing (ALT) is a well famous technique in life testing and reliability studies, this is particularly used to induce so high stress leading to failure of the highly reliable units quickly under stipulated duration of time. The step-stress ALT is one of the systematic experimental strategy of ALT applied to fail the units in steps. In this article we focus on two important issues (i) necessity of life tests at higher steps with relevant causes (ii) to develop a new optimum test plan for 3-step SSALT under the modified cumulative exposure model proposed by Khamis and Higgins (1998). It is assumed that the lifetime of test units follows Rayleigh distribution and its scale parameter at constant stress level is assumed to be a log-linear function of the stress. The maximum likelihood estimates of the parameters involved in the step-stress ALT model are obtained. A simulation study is performed for numerical investigation of the proposed new optimum plan 3-step, step-stress ALT. The necessity of the life test units at 3-step step-stress is also numerically examined in comparison to simple step-stress setup.

Bayesian reliability estimation of bivariate Marshal-Olkin exponential stress-strength model

Chandra, N.,Pandey, M. The Korean Reliability Society 2012 International Journal of Reliability and Applicati Vol.13 No.1

In this article we attempted reliability analysis of a component under the stress-strength pattern with both classical as well as Bayesian techniques. The main focus is made to develop the theory for dealing the reliability problems in various circumstances for bivariate environmental set up in context of Bayesian paradigm. A stress-strength based model describes the life of a component which has strength (Y) and is subjected to stress(X). We develop the Bayes and moment estimators of reliability of a component for each of the three possible conditions, under the assumption that the two stresses (i.e. $X_1$ and $X_2$) on a component are dependent and follow a Bivariate exponential (BVE) of Marshall-Olkin distribution, the strength of a component (Y) following exponential distribution is independent of the stresses. The simulation study is performed with Markov Chain Monte Carlo technique via Gibbs sampler to obtain the estimates of Bayes estimators of reliability, are compared with moment estimators of reliabilities on the basis of absolute biases.

Effect of Remote and Local Acupuncture Points on Periarthritis of Shoulder: A Comparative Study

Kumaresan Poorna Chandran,Prabu Poorna Chandran,Naveena Arumugam,Sendhilkumar Muthappan 사단법인약침학회 2021 Journal of Acupuncture & Meridian Studies Vol.14 No.1

Background: Periarthritis of shoulder is a painful condition of the shoulder, affecting 2-3% of the general population and 20% of diabetic patients. Acupuncture is a widely practiced traditional Chinese medicine. Recent evidence shows that it alleviates shoulder pain with different needling techniques. Objectives: The present study is to compare the efficacy of remote and local points on PAS. Methods: 60 subjects were randomly assigned into two groups, remote acupuncture group (n = 30) and local acupuncture group (n = 30). Both groups were assessed at baseline and at the end of 12 sessions. Shoulder pain and its disability index (SPADI) and (ROM) were measured using goniometer. The intervention was given weekly thrice on alternate days for four weeks with 20 min for each session. Results: The result shows that both remote and local acupuncture points were beneficial in the pain management and rage of motion when compared within the group. The effects of acupuncture at remote acupoints were better than those at local acupoints in SPADI and ROM when compared between two groups. Conclusion: In treatment of periarthritis of shoulder remote acupuncture points may have higher therapeutic value when compared to local points.

Resources for Systems Biology in Rice

Chandran, Anil Kumar Nalini,Jung, Ki-Hong 한국식물학회 2014 Journal of Plant Biology Vol.57 No.2

Systems biology is an upcoming trend in the field of functional genomics. Recently, there has been a significant improvement in the resources for systems biology in Oryza sativa (rice), a model crop. These resources include whole-genome sequencing/re-sequencing data, transcriptomes, protein-protein interactomes, reactomes, functional gene network tools, and gene indexed mutant populations. The integration of diverse omics data can lead to greater understanding of the functional genomics of rice. In this review, we address the development and current progress of the resources available for systems biology in rice: Genome browsers and databases for the orthology identification, transcriptome analysis, protein-protein interaction network and functional gene network analyses, a co-expression network, metabolic pathway analysis for promoter analysis, and gene indexed mutants.

Rice Male Gamete Expression Database (RMEDB): A Web Resource for Functional Genomic Studies of Rice Male Organ Development

Chandran Anil Kumar Nalini,Woo‑Jong Hong,Balachandran Abhijith,Yu‑Jin Kim,Soon Ki Park,Ki‑Hong Jung 한국식물학회 2020 Journal of Plant Biology Vol.63 No.6

Oryza sativa (rice) is an economically important crop, which is valued as a staple food source and as genetic model for cereals. Rice production needs to increase substantially to meet the growing global demand. Genetic studies have indicated that anther and pollen development genes can be used as targets to improve yield. Although several genes related to male organ developmental pathways have been characterized, the complete signaling network remains unclear. We used publicly available anther and pollen development transcriptome datasets to identify candidates for functional genomics studies. In addition, we newly generated RNA-Seq data for anther, anther wall and pollen samples with leaf sheath as control to provide the expression data for genes that are not covered by microarray technologies in rice. We constructed a platform, the rice male gamete expression database (RMEDB), comprising microarray and RNA-Seq based 188 transcriptome samples across diverse rice tissues and developmental stages of O. sativa japonica and O. sativa indica. Meta-expression analysis identified genes expressed at specific stages of anther or pollen developments. The functionalities in RMEDB database (http://ricephylogenomics-khu.org/RMEDB/home.php) can serve to identify candidates in male organ development for functional genomic studies of rice.

Effect of Residual Stress on Femoral Arterial Stress-Strain Behavior

Chandran, K.B.,Mun, J.H.,Chen, J.S.,Nagaraj, A.,McPherson, D.D. The Korean Society of Mechanical Engineers 2001 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.15 No.7

It is well established that arteries are subjected to residual stress. Due to the effect of residual stress, the arteries open to a horse-shoe shape when a longitudinal cut is made on an excised arterial segment. Previously, the residual stress has been quantified by the opening angle of the horse-shoe shape. We have employed a finite element analysis of the open arterial segment to restore the same to the original cylindrical shape and computed the circumferential strain as well as the stress distribution in the wall. In this study, the stress distribution in the femoral arteries of miniswine was computed with and without the residual stress for a range of transmural pressures. Our analysis showed that the residual stress has the effect of redistribution of the circumferential stresses between the intima and the adventitia under physiological loading. The redistribution of the stress with the inclusion of residual stress may be important in the studies on effect of wall stresses on the endothelial and vascular smooth muscle cells.

Supercharging a MnO₂ Nanowire: An Amine-Altered Morphology Retains Capacity at High Rates and Mass Loadings

Chandran, Girija Thesma,Jha, Gaurav,Qiao, Shaopeng,Le Thai, Mya,Dutta, Rajen,Ogata, Alana F.,Jang, Ji-Soo,Kim, Il-Doo,Penner, Reginald M. American Chemical Society 2017 Langmuir Vol.33 No.37

<P>The influence of hexamethylenetetraamine (HMTA) on the morphology of delta-MnO2 and its properties for electrical energy storage are investigated-specifically for ultrathick delta-MnO2 layers in the micron scale. Planar arrays of gold@delta MnO2, core@shell nanowires, were prepared by electrodeposition with and without the HMTA and their electrochemical properties were evaluated. HMTA alters the MnO2 in three ways: First, it creates a more open morphology for the MnO2 coating, characterized by 'petals' with a thickness of 6 to 9 nm, rather than much thinner delta-MnO2 sheets seen in the absence of HMTA. Second, the electronic conductivity of the delta-MnO2 is increased by an order of magnitude. Third, (delta-MnO2 prepared in HMTA shows a (001) interlayer spacing that is expanded by approximate to 30% possibly accelerating Li transport. The net effect of 'HTMA doping' is to dramatically improve high rate performance, culminating in an increase in the specific capacity for the thickest MnO2 shells examined here by a factor of 15 at 100 mV/s.</P>

Ni(II) complexes with ligands derived from phenylpyridine, active for selective dimerization and trimerization of ethylene

Chandran, D.,Lee, K.M.,Chang, H.C.,Song, G.Y.,Lee, J.E.,Suh, H.,Kim, I. Elsevier Sequoia 2012 Journal of organometallic chemistry Vol.718 No.-

An electrophilic substitution-carbonylation reaction on phenylpyridine based on the concept of 'umpolung' was used to prepare a series of pyridine based carbonyl compounds and bispyridine derivatives. The key intermediate which enhances this reaction is a base aggregate formed by the association of BuLi with lithium 2-dimethylaminoethanolate (LiDMAE) which is stabilized in nonpolar solvents. The presence of polar chelating amides that are used as acyl donors was found to collapse the superbase aggregates liberating nucleophilic 'free' BuLi. These nucleophiles lead a classical nucleophilic reaction to introduce butyl tails on the pre-ligand molecules. Pyridine carbonyl compounds produced by these electrophilic substitution-carbonylation reactions, on treatment with 2,6-diisopropylaniline and (DME)NiBr<SUB>2</SUB> in glacial acetic acid at reflux temperature, gave Ni(II) complexes in good yields in a one pot protocol. These complexes are active toward ethylene, producing selective dimerization and trimerization products.

Meta-expression analysis of unannotated genes in rice and approaches for network construction to suggest the probable roles

Chandran, Anil Kumar Nalini,Bhatnagar, Nikita,Yoo, Yo-Han,Moon, Sunok,Park, Sun-Ah,Hong, Woo-Jong,Kim, Beom-Gi,An, Gynheung,Jung, Ki-Hong Springer-Verlag 2018 Plant Molecular Biology Vol.96 No.1

<P>Although the genome of rice (Oryza sativa) has been sequenced, 14,365 genes are considered unannotated because they lack putative annotation information. According to the Rice Genome Annotation Project Database (http://rice.plantbiology.msu.edu/), the proportion of functionally characterized unannotated genes (0.35%) is quite limited when compared with the approximately 3.9% of annotated genes with assigned putative functions. Researchers require additional information to help them investigate the molecular mechanisms associated with those unannotated genes. To determine which of them might regulate morphological or physiological traits in the rice genome, we conducted a meta-analysis of expression data that covered a wide range of tissue/organ samples. Overall, 2020 genes showed cultivar-, tissue-, or organ-preferential patterns of expression. Representative candidates from featured groups were validated by RT-PCR, and the GUS reporter system was used to validate the expression of genes that were clustered according to their leaf or root preference. Taking a molecular and genetics approach, we examined meta-expression data and found that 127 genes were differentially expressed between japonica and indica rice cultivars. This is potentially significant for future agronomic applications. We also used a T-DNA insertional mutant and performed a co-expression network analysis of Sword shape dwarf1 (SSD1), a gene that regulates cell division. This network was refined via RT-PCR analysis. Our results suggested that SSD1 represses the expression of four genes related to the processes of DNA replication or cell division and provides insight into possible molecular mechanisms. Together, these strategies present a valuable tool for in-depth characterization of currently unannotated genes.</P>

Civil-Military Relations and National Security in ASEAN

( Chandran Jeshurun ) 인하대학교 국제관계연구소 1989 Pacific Focus Vol.4 No.2