Reliability analysis of multicomponent stress-strength reliability from a bathtub-shaped distribution.

In this paper, inference for a multicomponent stress-strength model is studied. When latent strength and stress random variables follow a bathtub-shaped distribution and the failure times are Type-II censored, the maximum likelihood estimate of the multicomponent stress-strength reliability (MSR) is established when there are common strength and stress parameters. Approximate confidence interval is also constructed by using the asymptotic distribution theory and delta method. Furthermore, another alternative generalized point and confidence interval estimators for the MSR are constructed based on pivotal quantities. Moreover, the likelihood and the pivotal quantities-based estimates for the MSR are also provided under unequal strength and stress parameter case. To compare the equivalence of the stress and strength parameters, the likelihood ratio test for hypothesis of interest is also provided. Finally, simulation studies and a real data example are given for illustration.

Inference for partially observed competing risks model for Kumaraswamy distribution under generalized progressive hybrid censoring.

In this paper, inference for a competing risks model is studied when latent failure times follow Kumaraswamy distribution and causes of failure are partially observed. Under generalized progressive hybrid censoring, existence and uniqueness of maximum likelihood estimators of model parameters are established. The confidence intervals are obtained by using asymptotic distribution theory. We further compute Bayes estimators along with credible intervals. In addition, inference is also discussed when there is order restricted shape parameters. The performance of all estimates is investigated using Monte-Carlo simulations. Finally, analysis of a real data set is presented for illustration purposes.

A nonlinear correlation measure with applications to gene expression data.

Nonlinear correlation exists in many types of biomedical data. Several types of pairwise gene expression in humans and other organisms show nonlinear correlation across time, e.g., genes involved in human T helper (Th17) cells differentiation, which motivated this study. The proposed procedure, called Kernelized correlation (Kc), first transforms nonlinear data on the plane via a function (kernel, usually nonlinear) to a high-dimensional (Hilbert) space. Next, we plug the transformed data into a classical correlation coefficient, e.g., Pearson's correlation coefficient (r), to yield a nonlinear correlation measure. The algorithm to compute Kc is developed and the R code is provided online. In three simulated nonlinear cases, when noise in data is moderate, Kc with the RBF kernel (Kc-RBF) outperforms Pearson's r and the well-known distance correlation (dCor). However, when noise in data is low, Pearson's r and dCor perform slightly better than (equivalently to) Kc-RBF in Case 1 and 3 (in Case 2); Kendall's tau performs worse than the aforementioned measures in all cases. In Application 1 to discover genes involved in the early Th17 cell differentiation, Kc is shown to detect the nonlinear correlations of four genes with IL17A (a known marker gene), while dCor detects nonlinear correlations of two pairs, and DESeq fails in all these pairs. Next, Kc outperforms Pearson's and dCor, in estimating the nonlinear correlation of negatively correlated gene pairs in yeast cell cycle regulation. In conclusion, Kc is a simple and competent procedure to measure pairwise nonlinear correlations.

Idealization through interactive modeling and experimental assessment of 3D-printed gyroid for trabecular bone scaffold.

Porous scaffolds assisted bone tissue engineering is a viable alternative for reconstruction of large segmental bone defects caused by bone pathologies or trauma. In the current study, we intend to develop trabecular bone scaffolds using gyroid architecture. An interactive modeling framework is developed for the design of three-dimensional gyroid scaffolds using advanced generative tools including K3DSurf, MeshLab, and Netfabb. The suggested modeling approach resulted in uniform and interconnected pores. Subsequently, fused deposition modeling 3D-printing is employed to fabricate the scaffolds using poly lactic acid material. The pores interconnectivity, porosity, and surface finish of the fabricated scaffolds are characterized using micro-computer tomography and scanning electron microscopy. Additionally, to assess the performance of scaffolds as a bone substitute, compression, and in-vitro biocompatibility tests on sterilized scaffolds are conducted. Compression tests reveal mechanical strength in the range of native bone while human adipose-derived mesenchymal stem cells show high proliferation after 72 h of incubation. Based on these results, the fabricated gyroid scaffolds can be said to possess favorable properties for trabecular bone scaffold.

Inference on a progressive type I interval-censored truncated normal distribution.

In this paper, we consider the problem of making statistical inference for a truncated normal distribution under progressive type I interval censoring. We obtain maximum likelihood estimators of unknown parameters using the expectation-maximization algorithm and in sequel, we also compute corresponding midpoint estimates of parameters. Estimation based on the probability plot method is also considered. Asymptotic confidence intervals of unknown parameters are constructed based on the observed Fisher information matrix. We obtain Bayes estimators of parameters with respect to informative and non-informative prior distributions under squared error and linex loss functions. We compute these estimates using the importance sampling procedure. The highest posterior density intervals of unknown parameters are constructed as well. We present a Monte Carlo simulation study to compare the performance of proposed point and interval estimators. Analysis of a real data set is also performed for illustration purposes. Finally, inspection times and optimal censoring plans based on the expected Fisher information matrix are discussed.

Phytochemical and pharmacological attributes of piperine: A bioactive ingredient of black pepper.

Plants are vital for the wellbeing of humankind in a variety of ways. Some plant extracts contain antimicrobial properties that can treat different pathogens. Most of the world's population relies on medicinal plants and natural products for their primary health care needs. Therefore, there is a growing interest in natural products, medicinal plants, and traditional medicine along with a desire to design and develop novel plant-based pharmaceuticals. These plant-based pharmaceuticals may address the concerns of reduced efficacy of synthetic antibiotics due to the emergence of drug-resistant pathogens. In this regard, some plant extracts from black pepper (Piper nigrum) with antimicrobial properties, including piperine, have the potential to be used as natural dietary supplements together with modern therapeutic approaches. This review highlights possible applications of piperine as the active compound in the fields of rational drug design and discovery, pharmaceutical chemistry, and biomedicine. We discuss different extraction methods and pharmacological effects of the analyzed substance to pave the way for further research strategies and perspectives towards the development of novel herbal products for better healthcare solutions.

Change in Oxidative Stress of Normotensive Elderly Subjects Following Lifestyle Modifications.

INTRODUCTION: Oxidative stress is associated with aging, which ultimately causes deterioration of muscles. Antioxidant defense system deteriorates while enhancing accumulations of Reactive Oxygen Species (ROS) due to lipid peroxidation and altered enzyme activities in old age. Regular practice of yoga can maintain the antioxidants level of the body, even in stressful conditions. AIM: The present study was designed to assess the effects of lifestyle technique on oxidative stress and lipid profile in normotensive elderly subjects. MATERIALS AND METHODS: Seventy four healthy elderly subjects (43 males and 31 females) 60 to 80 years of age were selected from the Santosh Medical College, Ghaziabad Uttar Pradesh, India, for three months lifestyle modification program which included morning walk, Nadi shodan pranayama, dietary restrictions and increased intake of water. Blood pressure and oxidative stress markers Glutathione (GSH), Super Oxide Dismutase (SOD) and Malondialdehyde (MDA) were recorded twice, one at baseline and another after three months of lifestyle modifications. RESULTS: Post lifestyle modifications technique values revealed a significant increase in GSH (88.03±9.58 ng/ml vs 93.12±9.17 ng/ml, p < 0.0001) and SOD (78.22±11.97 ng/ml vs 85.22±11.08 ng/ml, p < 0.0001), and a decline in MDA (5.28±0.52 m mol/ml vs 4.48± 0.69 m mol/ml, p < 0.0001) levels. Further, there was significant reduction in the systolic blood pressure (p <0.0001) and diastolic blood pressure (p<0.0002); besides all fasting lipids decreased significantly except High Density Lipids (HDL). CONCLUSION: The findings of the present study show that lifestyle modification is helpful in reducing cardiovascular disease risk but also assuring for good health by decreasing oxidative stress level along with lipid profile. Further, all these modifications are easy to follow. However, more studies are required to make a generalized lifestyle modification program in normotensive elderly subjects.

Effect of Left, Right and Alternate Nostril Breathing on Verbal and Spatial Memory.

INTRODUCTION: Yoga has beneficial effects on memory. In females, left hemisphere of the brain is responsible for verbal memory and right hemisphere is responsible for the spatial memory, while the opposite is true for males. AIM: Aim of the present was to study the effect of unilateral right nostril breathing, left nostril breathing and alternate nostril breathing on verbal and spatial memory scores. MATERIALS AND METHODS: A total of 51 female subjects (age 18-25 years, mean±SD =21.71±3.11) were taken and divided into three groups (n=17). Each group was imparted one of the three different types of nostril breathing practices such as Right Nostril Breathing (RNB), Left Nostril Breathing (LNB) and Alternate Nostril Breathing (ANB) for 1 week for 45 minutes daily. Subjects were given the memory test, before and after 45 minutes of intervention for three consecutive days. Memory tests were performed by using Wechsler Adult Intelligent Scale. STATISTICAL ANALYSIS: Results were analysed by ANOVA with SPSS version 17.0. RESULTS: Results showed that there was increase in recall of digit span-forward, digit-span backward, associate learning and spatial memory scores with RNB, LNB and ANB, which were statistically highly significant(p<0.005). CONCLUSION: Inclusion of nostril breathing in exercise regimen may be helpful in improving recall of memory.

Effect of isometric handgrip exercise training on resting blood pressure in normal healthy adults.

INTRODUCTION: The aim of the present study was to study the effect of isometric handgrip (IHG) exercise training on resting blood pressure in normal healthy volunteers. MATERIALS AND METHODS: Hand grip spring dynamometer was used for IHG exercise training. A total of 30 normal healthy volunteers in the age group of 20-40 y were enrolled for the study. Exercise training protocol consisted of five 3-min bouts of IHG exercise at 30% of maximum voluntary contraction separated by 5 min rest periods. Exercise was performed 3 times/wk for 10 wk. Subject's blood pressure was measured before and after exercise. RESULT: There was a significant reduction in resting blood pressure following 10 wk of exercise training. Both Systolic and Diastolic blood pressure reduced significantly (p<0.001). CONCLUSION: IHG exercise training might be a simple, effective, inexpensive and non-pharmacological method in lowering blood pressure.

The isometric handgrip exercise as a test for unmasking hypertension in the offsprings of hypertensive parents.

BACKGROUND: A familial history of hypertension increases the risk of hypertension in the offsprings. AIMS AND OBJECTIVES: The present study was undertaken to assess the underlying hypertension by using the Isometric Handgrip (IHG) exercise test in the offsprings of hypertensive parents and to compare it with age-matched controls of normotensive parents. MATERIAL AND METHODS: The isometric handgrip test was performed in the study and control groups. The resting blood pressure was recorded before exercise and afterwards the subjects were asked to perform the isometric handgrip exercise with the dominant hand for 2 minutes. Then the blood pressure was recorded in the sitting position during and 5 minutes after the completion of the exercise. STATISTICAL ANALYSIS: The analysis of the results was done by ANOVA with SPSS, version 17.0, by using the unpaired 't' test. RESULTS: The results showed that the Resting Systolic (SBP), Diastolic (DBP) and the Mean (MBP) Blood Pressures were higher (p <0.001) in the offsprings of the hypertensive parents as compared to those in the control subjects of normotensive parents. During the isometric handgrip exercise test, the rise in the systolic, diastolic and the mean blood pressures was significantly higher (p<0.001) in the offsprings of the hypertensive parents. After 5 minutes of exercise, the SBP, DBP and the MBP were found to be significantly higher (p<0.001) in the study group as compared to those in the control group. CONCLUSIONS: An early and a regular screening of the children of hypertensive parents is necessary to prevent any future cardiovascular complications.