Microstructure, hardness and wear behavior of ZrC particle reinforced AZ31 surface composites synthesized via friction stir processing

Dry sliding wear behaviour of friction stir processed (FSP) AZ31 and AZ31/ZrC particles (5, 10, and 15 vol%) reinforced surface composite was investigated at different sliding speeds and loads. The samples were tested using a pin-on-disc apparatus with EN31 steel as the counter body to determine the role of FSP and ZrC reinforcement on the microstructure, hardness, and wear behaviour of AZ31. Base metal AZ31 alloy exhibits a hardness of 60 HV, whereas the 15 vol% ZrC-reinforced composites had the highest hardness of 108 HV. It was also identified that 15 vol% ZrC-reinforced composites exhibited lowest wear rate and friction coefficient under all testing conditions. Abrasion, delamination, oxidation, material softening, and plastic deformation are the primary wear mechanisms viewed from the wear tracks of the samples. Higher volume fraction of ZrC particles exhibited better wear resistance at all speeds and loads than AZ31 alloy. A wear map has been generated for different material compositions and wear conditions to identify the main wear mechanisms easily.

How to Perform Discriminant Analysis in Medical Research? Explained with Illustrations

Discriminant function analysis is the statistical analysis used to analyze data when the dependent variable or outcome is categorical and independent variable or predictor variable is parametric. It is a parametric technique to determine which weightings of quantitative variables or predictors best discriminates between two or more than two categories of dependent variables and does so better than chance. Discriminant analysis is used to find out the accuracy of a given classification system in predicting the sample into a particular group. Discriminant analysis includes the development of discriminant functions for each sample and deriving a cutoff score that is used for classifying the samples into different groups. Discriminant function analysis is a statistical analysis used to find out the accuracy of a given classification system or predictor variables. This article explains the basic assumptions, uses, and necessary requirements of discriminant analysis with a real-life clinical example. Whenever a new classification system is introduced, discriminant function analysis can be used to find out the accuracy with which the classification is able to differentiate a particular sample into different groups. Thus, it is a very useful tool in medical research where classification is required.

Effect of multidirectional and unidirectional wobble board lateral step-upexercise in pain, symptom and ADLamong unilateral medial compartmental osteoarthrosis of knee

Introduction and Aim:Osteoarthrosis is defined as degenerative condition of the synovial joints. Weak thigh muscle will cause impaired walking and balance and leads to risk of fall during activities of daily living. Use of MD and UD wobble board is hypothesized to improve balance and proprioception. So, pain, muscle power and proprioception are clinically important for balance control. Hence there is a need to study weight bearing exercise to hip abductor in various balance strategies to achieve muscle strength, joint position sense, balance, and activity of daily living.   Methodology: Knee osteoarthrosis subjects(n=219) were selected according to selection criteria andwere randomly allocated into 3 groups as multidirectional wobble board lateral step-up exercise group, unidirectional wobble board lateral step-up exercise group and control group. The pre-test KOOS pain, symptoms and ADL measurements were taken before the intervention and another measurement during the 2nd week of intervention and at the end of the intervention period during 4thweek post-test measurements were measured and statistically analysed.   Results:  At the end of 4th week control, UD and MD was found to be statistically significant with H=200.192 with p<0.001. KOOS symptoms between 3 groups was found to be statistically significant with H=200.288 and p <0.001. KOOS ADL values was found to be statistically significant between 3 groups with H=193.640 and p<0.001.   Conclusion: This study concludes that both unidirectional and multidirectional wobble board lateral step-up exercise showed improvement with KOOS pain, symptom and ADL scores compared to control group.

How to Analyze the Diagnostic Performance of a New Test? Explained with Illustrations

Diagnostic tests are pivotal in modern medicine due to their applications in statistical decision-making regarding confirming or ruling out the presence of a disease in patients. In this regard, sensitivity and specificity are two most important and widely utilized components that measure the inherent validity of a diagnostic test for dichotomous outcomes against a gold standard test. Other diagnostic indices like positive predictive value, negative predictive value, positive likelihood ratio, negative likelihood ratio, accuracy of a diagnostic test, and the effect of prevalence on various diagnostic indices have also been discussed. We have tried to present the performance of a classification model at all classification thresholds by reviewing the receiver operating characteristic (ROC) curve and the depiction of the tradeoff between sensitivity and (1–specificity) across a series of cutoff points when the diagnostic test is on a continuous scale. The area under the ROC (AUROC) and comparison of AUROCs of different tests have also been discussed. Reliability of a test is defined in terms of the repeatability of the test such that the test gives consistent results when repeated more than once on the same individual or material, under the same conditions. In this article, we have presented the calculation of kappa coefficient, which is the simplest way of finding the agreement between two observers by calculating the overall percentage of agreement. When the prevalence of disease in the population is low, prospective study becomes increasingly difficult to handle through the conventional design. Hence, we chose to describe three more designs along with the conventional one and presented the sensitivity and specificity calculations for those designs. We tried to offer some guidance in choosing the best possible design among these four designs, depending on a number of factors. The ultimate aim of this article is to provide the basic conceptual framework and interpretation of various diagnostic test indices, ROC analysis, comparison of diagnostic accuracy of different tests, and the reliability of a test so that the clinicians can use it effectively. Several R packages, as mentioned in this article, can prove handy during quantitative synthesis of clinical data related to diagnostic tests.

Pathological changes in ureterovesical and ureteropelvic junction obstruction explained by fetal ureter histology

The etiology of ureterovesical junction obstruction (UVJO) and ureteropelvic junction obstruction (UPJO) is obscure with an adynamic narrow segment causing the obstruction. In this study, the authors compared interstitial cells of Cajal (ICC) and collagen-to-muscle ratio (CM ratio) between UVJO, UPJO, and fetal ureters to investigate whether a maturational arrest of the fetal ureter could explain both clinical pathologies.

METHODS

Group 1 (control) involved specimens of the normal ureter (nephrectomy for trauma/tumor; n = 20), while group 2, specimens of UVJO (n = 14); group 2 was further divided into group 2a, the dilated megaureter above UVJO, and group 2b, UVJO narrow segment; group 3, UPJO narrow segment excised during pyeloplasty (n = 31); and group 4, normal fetal ureters (n = 12). The specimens were analyzed for ICC using immunohistochemistry and CM ratio on Masson's trichrome (stains collagen in blue and muscle in red).

RESULTS

The median ICC/10 high-power field was 16.1 (8.3) in the normal and 17.3 (7.9) in the dilated segment of the megaureter, with no significant difference, but was significantly less in the narrow segment of UVJO at 4.5 (2.0), narrow segment of UPJO at 5.1 (2.3), and fetal ureter at 5.0 (2.3). The median CM ratio was 0.75 (0.29) in the normal and 0.65 (0.2) in the dilated segment of the megaureter, with no significant difference between them (figure), but was significantly higher in the narrow segment of UVJO at 3.0 (0.8), narrow segment of UPJO at 2.5 (0.71), and fetal ureter at 3.1 (0.61). Overall UVJO, UPJO, and fetal ureter segment had significantly less ICC density and more collagen compared with the normal ureter (P < 0.001 by Mann-Whitney U test).

DISCUSSION

There are conflicting reports on the etiopathogenesis of UVJO and UPJO, with several authors showing decreased ICC and increased collagen in the narrow segment. In this study, the authors found that the pathological changes at UVJ and UPJ segments resemble fetal ureter morphology. We also found that in fetal ureters, as the gestation progressed, there was an increase in the ICC density/smooth muscle, whereas the collagen content decreased. While the entire ureter has uniform embryological origin, it essentially remains an epithelial tube until the late gestation. The maturational process involves differentiation of smooth muscles cells/ICC to establish the peristaltic machinery required to functionally connect the ureter at both ends. This process, probably, starts at the mid ureter during fetal life and extends toward the UPJ and UVJ, and its failure, probably, results in UPJO or UVJO. The study's limitations are small numbers, and further larger studies are required to validate this hypothesis.

Caspase-2 deficiency accelerates chemically induced liver cancer in mice

Aberrant cell death/survival has a critical role in the development of hepatocellular carcinoma (HCC). Caspase-2, a cell death protease, limits oxidative stress and chromosomal instability. To study its role in reactive oxygen species (ROS) and DNA damage-induced liver cancer, we assessed diethylnitrosamine (DEN)-mediated tumour development in caspase-2-deficient (Casp2(-/-)) mice. Following DEN injection in young animals, tumour development was monitored for 10 months. We found that DEN-treated Casp2(-/-) mice have dramatically elevated tumour burden and accelerated tumour progression with increased incidence of HCC, accompanied by higher oxidative damage and inflammation. Furthermore, following acute DEN injection, liver injury, DNA damage, inflammatory cytokine release and hepatocyte proliferation were enhanced in mice lacking caspase-2. Our study demonstrates for the first time that caspase-2 limits the progression of tumourigenesis induced by an ROS producing and DNA damaging reagent. Our findings suggest that after initial DEN-induced DNA damage, caspase-2 may remove aberrant cells to limit liver damage and disease progression. We propose that Casp2(-/-) mice, which are more susceptible to genomic instability, are limited in their ability to respond to DNA damage and thus carry more damaged cells resulting in accelerated tumourigenesis.

Ambient temperature operated acetaldehyde vapour detection of spray deposited cobalt doped zinc oxide thin film

Undoped and Co-doped ZnO thin films were prepared by a home built spray pyrolysis method. X-ray diffraction results indicate that both undoped and Co-doped ZnO have a polycrystalline nature and a preferential orientation peak in the (002) plane. From a field-emission scanning electron micrographs of annealed films, a uniform distribution of nanoparticles along with nanorods was observed. UV-Visible measurement indicated that all the films are transparent in the visible region. The electrical resistance was also reported. The acetaldehyde sensing behaviour of the prepared undoped and Co-doped ZnO thin films was studied using the chemi-resistive method at ambient temperature (∼30 °C). In the presence of 10 ppm of acetaldehyde vapour, the Co-doped ZnO thin films showed good sensing response of 74% with fast response and recovery time of 3 s and 110 s respectively.

Comparison of nutritional status of rural and urban school students receiving midday meals in schools of Bengaluru, India: a cross sectional study

BACKGROUND

The objective of the study was to assess the impact of the mid day meal program by assessing the nutritional status of school students aged 5-15 years receiving midday meals in rural schools and compare them with those in urban schools in Bengaluru, India.

MATERIALS AND METHODS

This cross sectional study involved a sample of 4378 students from government and aided schools. Weight and height were measured and compared with ''means'' and ''percentiles'' of expected standards as endorsed by the Indian Association of Pediatrics. Regression coefficients were also estimated to assess the rate of growth.

RESULTS

In all age groups and in both sexes, the observed mean weight and height were below the expected standards. The study findings showed that 13.8% and 13.1% of the studied students were underweight and stunted, respectively (below the third percentile for weight and height for age). A higher proportion of rural students were below the third percentile for both weight and height compared with urban students (weight: 16.3% and 11.5%; height: 17.0% and 10.0%; P < 0.05 for both weight and height). Only 2.4% and 3.1% were above 97 th percentile for weight and height. The rate of growth of height for weight showed a declining trend with increasing age in all the groups.

DISCUSSION

The authors believe that the magnitude of the burden of undernourished students as seen in this study would have been much greater in the absence of the midday meal program.

CONCLUSION

Greater involvement of the private sector to assist the government would help augment nutrition in children and indirectly impact school performance, attendance and literacy.

Old, new and emerging functions of caspases

Caspases are proteases with a well-defined role in apoptosis. However, increasing evidence indicates multiple functions of caspases outside apoptosis. Caspase-1 and caspase-11 have roles in inflammation and mediating inflammatory cell death by pyroptosis. Similarly, caspase-8 has dual role in cell death, mediating both receptor-mediated apoptosis and in its absence, necroptosis. Caspase-8 also functions in maintenance and homeostasis of the adult T-cell population. Caspase-3 has important roles in tissue differentiation, regeneration and neural development in ways that are distinct and do not involve any apoptotic activity. Several other caspases have demonstrated anti-tumor roles. Notable among them are caspase-2, -8 and -14. However, increased caspase-2 and -8 expression in certain types of tumor has also been linked to promoting tumorigenesis. Increased levels of caspase-3 in tumor cells causes apoptosis and secretion of paracrine factors that promotes compensatory proliferation in surrounding normal tissues, tumor cell repopulation and presents a barrier for effective therapeutic strategies. Besides this caspase-2 has emerged as a unique caspase with potential roles in maintaining genomic stability, metabolism, autophagy and aging. The present review focuses on some of these less studied and emerging functions of mammalian caspases.

An unexpected role for caspase-2 in neuroblastoma

Caspase-2 has been implicated in various cellular functions, including cell death by apoptosis, oxidative stress response, maintenance of genomic stability and tumor suppression. The loss of the caspase-2 gene (Casp2) enhances oncogene-mediated tumorigenesis induced by E1A/Ras in athymic nude mice, and also in the Eμ-Myc lymphoma and MMTV/c-neu mammary tumor mouse models. To further investigate the function of caspase-2 in oncogene-mediated tumorigenesis, we extended our studies in the TH-MYCN transgenic mouse model of neuroblastoma. Surprisingly, we found that loss of caspase-2 delayed tumorigenesis in the TH-MYCN neuroblastoma model. In addition, tumors from TH-MYCN/Casp2^−/− mice were predominantly thoracic paraspinal tumors and were less vascularized compared with tumors from their TH-MYCN/Casp2^+/+ counterparts. We did not detect any differences in the expression of neuroblastoma-associated genes in TH-MYCN/Casp2^−/− tumors, or in the activation of Ras/MAPK signaling pathway that is involved in neuroblastoma progression. Analysis of expression array data from human neuroblastoma samples showed a correlation between low caspase-2 levels and increased survival. However, caspase-2 levels correlated with clinical outcome only in the subset of MYCN-non-amplified human neuroblastoma. These observations indicate that caspase-2 is not a suppressor in MYCN-induced neuroblastoma and suggest a tissue and context-specific role for caspase-2 in tumorigenesis.

rac-3-(4-Hy-droxy-benz-yl)chroman-4-one

In the racemic title compound, C16H14O3, the ring of the 4-hy-droxy-benzyl substituent group forms a dihedral angle of 80.12 (12)° with the benzene ring of the chromanone system. Two C atoms of the pyran-one ring and the H atoms on the benzyl α-C atom are disordered over two sites, with site-occupation factors of 0.818 (8) and 0.182 (8). The crystal structure is stabilized by O-H⋯O hydrogen bonds, which form parallel one-dimensional zigzag chains down the c axis and are inter-connected by both methine C-H⋯O hydrogen bonds and weak aromatic C-H⋯π inter-actions, giving a sheet structure lying parallel to [011].

3-(3,4-Dimeth-oxy-benz-yl)chroman-4-one

In the title compound, C₁₈H₁₈O₄, the six-membered chroman-4-one ring adopts an envelope conformation with the C atom bonded to the bridging CH₂ atom as the flap. The dihedral angle between the mean plane of the fused pyranone ring and the dimeth­oxy-substituted benzene ring is 89.72 (2)°. In the crystal, adjacent molecules are linked via C—H⋯π inter­actions.

Caspase-2 deficiency promotes aberrant DNA-damage response and genetic instability

Caspase-2 is an initiator caspase, which has been implicated to function in apoptotic and non-apoptotic signalling pathways, including cell-cycle regulation, DNA-damage signalling and tumour suppression. We previously demonstrated that caspase-2 deficiency enhances E1A/Ras oncogene-induced cell transformation and augments lymphomagenesis in the EμMyc mouse model. Caspase-2(-/-) mouse embryonic fibroblasts (casp2(-/-) MEFs) show aberrant cell-cycle checkpoint regulation and a defective apoptotic response following DNA damage. Disruption of cell-cycle checkpoints often leads to genomic instability (GIN), which is a common phenotype of cancer cells and can contribute to cellular transformation. Here we show that caspase-2 deficiency results in increased DNA damage and GIN in proliferating cells. Casp2(-/-) MEFs readily escape senescence in culture and exhibit increased micronuclei formation and sustained DNA damage during cell culture and following γ-irradiation. Metaphase analyses demonstrated that a lack of caspase-2 is associated with increased aneuploidy in both MEFs and in EμMyc lymphoma cells. In addition, casp2(-/-) MEFs and lymphoma cells exhibit significantly decreased telomere length. We also noted that loss of caspase-2 leads to defective p53-mediated signalling and decreased trans-activation of p53 target genes upon DNA damage. Our findings suggest that loss of caspase-2 serves as a key function in maintaining genomic integrity, during cell proliferation and following DNA damage.

Impaired antioxidant defence and accumulation of oxidative stress in caspase-2-deficient mice

Caspase-2 has been implicated in apoptosis and in non-apoptotic processes such as cell cycle regulation, tumor suppression and ageing. Using caspase-2 knockout (casp2(-/-)) mice, we show here that the putative anti-ageing role of this caspase is due in part to its involvement in the stress response pathway. The old casp2(-/-) mice show increased cellular levels of oxidized proteins, lipid peroxides and DNA damage, suggesting enhanced oxidative stress. Furthermore, murine embryonic fibroblasts from casp2(-/-) mice showed increased reactive oxygen species generation when challenged with pro-oxidants. Reduced activities of antioxidant enzymes glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) were observed in the old casp2(-/-) mice. Interestingly, in the old casp2(-/-) animals expression of FoxO1 and FoxO3a was significantly reduced, whereas p21 levels and the number of senescent hepatocytes were elevated. In contrast to young wild-type mice, the casp2(-/-) animals fed an on ethanol-based diet failed to show enhanced GSH-Px and SOD activities. Thus, caspase-2, most likely via FoxO transcription factors, regulates the oxidative stress response in vivo.

(1E,4E)-1,5-Bis(thio-phen-3-yl)penta-1,4-dien-3-one

The title compound, C₁₃H₁₀OS₂, exhibits twists between the central C₃O and ethene residues [O—C—C—C torsion angles = −8.4 (3) and 11.8 (3)°], and between the ethene and adjacent thio­phenyl residues [C—C—C—C torsion angles = −4.2 (3) and 10.5 (3)°]. As a result, the mol­ecule is non-planar, the dihedral angle formed between the terminal thio­phenyl groups being 15.45 (10)°. The presence of C—H⋯O inter­actions involving the bifurcated carbonyl O atom leads to supra­molecular arrays in the ac plane. These are linked into a three-dimensional architecture by C—H⋯π inter­actions involving both thio­phenyl residues.

Changing trends in incidence of ovarian cancer - the Indian scenario

Ovarian cancer has emerged as one of the most common malignancies affecting women in India. The present communication reports the trends in the incidence rate of ovarian cancer for Indian women. The data published in Cancer Incidence in Five Continents for various Indian registries for different periods and / or publication by the individual registries served as the source material. Mean annual percentage change (MAPC) in rates was computed using relative differences between two time periods. During the period 2001-06, the age-standardized incidence rates (ASR) for ovarian cancer varied from 0.9 to 8.4 per 100,000 person years amongst various registries. The highest incidence was noted in Pune and Delhi registries. The Age Specific Incidence Rate (ASIR) for ovarian cancer revealed that the disease increases from 35 years of age and reaches a peak between the ages 55-64. The trend analysis by period showed an increasing trend in the incidence rate of ovarian cancer in most of the registries, with a mean annual percentage increase in ASR ranged from 0.7% to 2.4 %. Analysis of data by ASIR revealed that the mean annual percentage increase was higher for women in the middle and older age groups in most of the registries. Estimation of annual percent change (EAPC) in ovarian cancer by Poisson regression model through Maximum Likelihood Estimation (MLE) for the data of 3 population-based cancer registries vs. Mumbai, Chennai and Bangalore for the period 1983-2002 revealed that linear regression was found to be satisfactory fit between period and incidence rate. Statistically significant increase in EAPC was noted with the crude rate (CR,) ASR, and ASIR for several age-groups. Efforts should be made to detect ovarian cancer at an early stage by educating population about the risk factors. Most of the ovarian cancers are environmental in origin and consequently, at least in principle avoidable.

Synthesis and Biological Screening of 5-{[(4,6-Disubstituted pyrimidine-2-yl)thio]methyl}-N-phenyl-1,3,4-thiadiazol-2-amines

A number of substituted-α,β-unsaturated carbonyl compounds (1a-i) were prepared by Claisen-Schmidt condensation of substituted acetophenone with selected araldehydes, which on cycloaddition with thiourea furnished 4,6-disubstituted pyrimidine-2-thiols (2a-i). Reaction of (2a-i) with ethyl chloroacetate followed by condensation with hydrazine hydrate yielded 2-[(4,6-disubstituted pyrimidine-2-yl) thio] acetohydrazides (4a-c). Condensation of compounds (4a-c) with phenyl isothiocyanate gave 2-{[(4,6-disubstituted pyrimidine-2-yl) thio] acetyl}-N-phenylhydrazinecarbothioamides (5a-c) which on treatment with concentrated sulphuric acid afforded titled compounds 5-{(4,6-disubstituted pyrimidine-2-yl) thio] methyl}-N-phenyl-1,3,4-thiadiazole-2-amines (6a-c). These compounds have been characterized on the basis of elemental analysis, IR, (1)H NMR and MS. Compounds have been evaluated for their anticancer and antioxidant activities. Compounds 2b, 2c and 6b exhibited significant antitumor activity against human breast cancer MCF 7 cell line. However, moderate antioxidant activity was observed with compounds 2c, 2d, 2g and 6b.

Efficacy and tolerability of Dianex in Type 2 diabetes mellitus: a non randomized, open label non-comparative study

OBJECTIVE AND STUDY DESIGN

A nonrandomized open labeled clinical trial to evaluate the efficacy and tolerability of Dianex (a poly herbal formulation developed by Apex Laboratories [PVT] Chennai, Tamil Nadu, India) in type 2 diabetes mellitus was carried out during a 6-month period.

SETTING/LOCATION

This study was conducted in TMA Pai Hospital, Udupi, South India.

SUBJECTS

A total of 40 patients were recruited for this study. Three patients dropped out of the study leaving a total of 37 patients (11 for monotherapy and 26 for add on therapy).

OUTCOME MEASURES

Eighteen (18) clinical variables were investigated, including liver enzymes, kidney function tests, hematologic parameters, blood glucose, and insulin and lipid profiles.

RESULTS

at the end of 12 weeks it was found that there was a significant decrease in the level of glycated hemoglobin, fasting plasma insulin level, insulin resistance, and systolic and diastolic blood pressure. At the end of 24 weeks results were similar to those at 12 weeks. Dianex did not alter the liver function tests, hematological parameters, or kidney function tests.

CONCLUSION

In this preliminary study, Dainex is found to be an effective adjuvant drug with either oral antidiabetic agents or insulin that can be used in the control of blood sugars in diabetic patients. Dianex is a safe drug that does not cause any clinical, hematological or biochemical alteration in major organ systems.