Parameter design for MIG welding of Al-65032 alloy using Taguchi technique

844-850This study presents Taguchi method to design process parameters that optimize mechanical properties of weld specimen for aluminum alloy (Al-65032), used for construction of aerospace wings. Process parameters of MIG welding setup considered are gas pressure, current, groove angle and pre-heat. Assigning process parameters to L-9 orthogonal array, experiments were conducted and optimization condition was obtained along with the identification of most influencing parameters using S/N analysis, mean response analysis and ANOVA

Effect of medication and deep brain stimulation on gait in Parkinson's disease and its quantitative analysis using Mobishoe – A comparative study

Background: Movement abnormalities pertaining to balance, posture, and gait are observed in Parkinson's disease patients. Gait characteristics vary widely and their analysis has been performed traditionally in gait labs. Freezing and festination usually occur at an advanced stage of the disease and are associated with reduced quality of life. Therapeutic strategies and surgical interventions are often modulated by the physician depending upon the clinical manifestations. Introduction of accelerometers and wireless data transmission systems made quantitative gait analysis possible and cost-effective. Objective: To assess spatiotemporal gait parameters (step height, length (spatial), and swing support time of each foot and double support time (temporal)) in subjects who underwent deep brain stimulation surgery using a purpose-built instrument—Mobishoe. Methods: A simple footwear-based gait sensing device—Mobishoe was built in-house. Thirty-six participants were included in the study after obtaining consent. Participants were made to wear Mobishoe and walk an empty corridor of 30m before Deep Brain Stimulation (DBS) in the drug on and off stated and post DBS in DBS stimulation on and medication off state (B1M0), DBS stimulation off—medication off state (B0M0), DBS stimulation off—medication on (B0M1), and DBS stimulation on and on medication (B1M1). Data was electronically captured and analyzed offline in MATrix LABoratory (MATLAB). Various gait parameters were extracted and analyzed. Results: Improvement in gait parameters was observed when the subject was on medication, on stimulation, or on both when compared to baseline. Improvement was similar with both medication and stimulation and was synergistic when both were used. Significant improvement was noted in spatial characteristics when the subjects were on both the treatments, which is the ideal treatment modality. Conclusion: Mobishoe is an affordable device which can measure spatiotemporal characteristics of gait. The best improvement was seen when the subjects were on both the treatment groups and the improvement can be justified as a synergistic effect of stimulation and medication

Epidemiology and genetics of hypertrophic cardiomyopathy

Background: Hypertrophic cardiomyopathy (HCM) is a heart muscle disorder and is known to be inherited as an autosomal dominant trait. Mutations in several sarcomeric, cytoskeletal and mitochondrial genes have been reported in HCM. Though many cases of HCM are being identified, there is limited data regarding the epidemiology and genetics of HCM in India. Aim: Therefore the present study is envisaged at identifying the epidemiological variables in HCM and fitting a probability model assuming dominant mode of inheritance in HCM, which may in turn shed light on the heterogeneity of this complex disorder. Materials AND Methods: The 127 HCM cases were divided into subtypes based on pattern of hypertrophy. Chi square analysis, odds ratio, probability, relative frequency, penetrance and heritability estimates were calculated apart from epidemiological variables. Results: The HCM subtypes revealed the heterogeneous nature of the condition suggesting that the genes/mutations involved in their pathogenesis are different and this is supported by distinctive differences observed in their probability, heritability and penetrance estimates apart from epidemiological variables. An increased male preponderance was observed with the sex ratio being 3.7:1. The age at onset was found to be more than a decade early in familial cases (30 ± 10 yrs) compared to non familial cases (44 ± 14 yrs). Chi square analysis revealed obstructive HCM to be following autosomal dominant mode of inheritance where as non-obstructive HCM was significantly deviating. The level of deviation was significantly high for the middle onset group compared to early and late onset groups, therefore this group may be considered as an admixture wherein genes/gene modifiers and environmental variables may be contributing to the heterogeneity and this is further supported by odds ratio. Conclusions: The study thus brings out the complexity of HCM and suggests that modes of inheritance other than autosomal dominant may be encountered in a subset of HCM especially in asymmetric septal hypertrophy, apical, concentric and mid cavity obstruction subsets and hence a mixed model of inheritance is the best fit for such complex disorders