105 research outputs found

    Fabrication and analysis of mechanical properties of PVC/Glass fiber/graphene nano composite pipes

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    The aim of this work is to examine the conventional moulding method for manufacturing the PVC/Glass fiber/graphene nano composites. Uniform graphene dispersion is observed with the matrix for better bonding. The Mechanical properties of the manufactured nano composites have been done in this work. Three important standard tests were evaluated for the performance of Nano-Composites developed. The composites were developed as flat specimen for pipe applications. The three standards test which includes axial tension, compression and transverse compression is studied. The graphene nano composites were varied 0.5%, 1%, 1.5% and 2 percentages. Based on the results it can be concluded that the increase in the percentages of graphene made a uniform dispersion, which leads to increase in the compressive strength of the Nanocomposite. Increase in the axial compressive strength and stiffness was observed and the increase in the trend value is mainly observed in 1.5 wt% and 2 wt% respectively. The Graphene dispersion and fractured surface morphology of nano composites were examined using scanning electronic microscopy (SEM).It can also be used as an alternative for metal pipes in industries

    Chronic Kidney Disease and Cognitive Function in Older Adults: Findings from the Chronic Renal Insufficiency Cohort Cognitive Study

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    To investigate cognitive impairment in older, ethnically diverse individuals with a broad range of kidney function, to evaluate a spectrum of cognitive domains, and to determine whether the relationship between chronic kidney disease (CKD) and cognitive function is independent of demographic and clinical factors.Cross-sectional.Chronic Renal Insufficiency Cohort Study.Eight hundred twenty-five adults aged 55 and older with CKD.Estimated glomerular filtration rate (eGFR, mL/min per 1.73 m 2 ) was estimated using the four-variable Modification of Diet in Renal Disease equation. Cognitive scores on six cognitive tests were compared across eGFR strata using linear regression; multivariable logistic regression was used to examine level of CKD and clinically significant cognitive impairment (score ≤1 standard deviations from the mean).Mean age of the participants was 64.9, 50.4% were male, and 44.5% were black. After multivariable adjustment, participants with lower eGFR had lower cognitive scores on most cognitive domains ( P <.05). In addition, participants with advanced CKD (eGFR<30) were more likely to have clinically significant cognitive impairment on global cognition (adjusted odds ratio (AOR) 2.0, 95% CI=1.1–3.9), naming (AOR=1.9, 95% CI=1.0–3.3), attention (AOR=2.4, 95% CI=1.3–4.5), executive function (AOR=2.5, 95% CI=1.9–4.4), and delayed memory (AOR=1.5, 95% CI=0.9–2.6) but not on category fluency (AOR=1.1, 95% CI=0.6–2.0) than those with mild to moderate CKD (eGFR 45–59).In older adults with CKD, lower level of kidney function was associated with lower cognitive function on most domains. These results suggest that older patients with advanced CKD should be screened for cognitive impairment.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/78647/1/j.1532-5415.2009.02670.x.pd

    Multiple ionization of argon via multi-XUV-photon absorption induced by 20-GW high-order harmonic laser pulses

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    We report the observation of multiple ionization of argon through multi-XUV-photon absorption induced by an unprecedentedly powerful laser driven high-order harmonic generation source. Comparing the measured intensity dependence of the yield of the different argon charge states with numerical calculations we can infer the different channels—direct and sequential—underlying the interaction. While such studies were feasible so far only with free electron laser (FEL) sources, this paper connects highly nonlinear XUV processes with the ultrashort time scales inherent to the harmonic pulses and highlights the advanced perspectives of emerging large scale laser research infrastructures

    Anemia and risk for cognitive decline in chronic kidney disease

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    BACKGROUND: Anemia is common among patients with chronic kidney disease (CKD) but its health consequences are poorly defined. The aim of this study was to determine the relationship between anemia and cognitive decline in older adults with CKD. METHODS: We studied a subgroup of 762 adults age ≥55 years with CKD participating in the Chronic Renal Insufficiency Cohort (CRIC) study. Anemia was defined according to the World Health Organization criteria (hemoglobin <13 g/dL for men and <12 g/dL for women). Cognitive function was assessed annually with a battery of six tests. We used logistic regression to determine the association between anemia and baseline cognitive impairment on each test, defined as a cognitive score more than one standard deviation from the mean, and mixed effects models to determine the relation between anemia and change in cognitive function during follow-up after adjustment for demographic and clinical characteristics. RESULTS: Of 762 participants with mean estimated glomerular filtration rate of 42.7 ± 16.4 ml/min/1.73 m(2), 349 (46 %) had anemia. Anemia was not independently associated with baseline cognitive impairment on any test after adjustment for demographic and clinical characteristics. Over a median 2.9 (IQR 2.6–3.0) years of follow-up, there was no independent association between anemia and change in cognitive function on any of the six cognitive tests. CONCLUSIONS: Among older adults with CKD, anemia was not independently associated with baseline cognitive function or decline. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12882-016-0226-6) contains supplementary material, which is available to authorized users

    Inactivation of the transforming growth factor β type II receptor in human small cell lung cancer cell lines

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    Transforming growth factor β (TGF-β) exerts a growth inhibitory effect on many cell types through binding to two types of receptors, the type I and II receptors. Resistance to TGF-β due to lack of type II receptor (RII) has been described in some cancer types including small cell lung cancer (SCLC). The purpose of this study was to examine the cause of absent RII expression in SCLC cell lines. Northern blot analysis showed that RII RNA expression was very weak in 16 of 21 cell lines. To investigate if the absence of RII transcript was due to mutations, we screened the poly-A tract for mutations, but no mutations were detected. Additional screening for mutations of the RII gene revealed a GG to TT base substitution in one cell line, which did not express RII. This mutation generates a stop codon resulting in predicted synthesis of a truncated RII of 219 amino acids. The nature of the mutation, which has not previously been observed in RII, has been linked to exposure to benzo[a]-pyrene, a component of cigarette smoke. Since RII has been mapped to chromosome 3p22 and nearby loci are often hypermethylated in SCLC, it was examined whether the lack of RII expression was due to hypermethylation. Southern blot analysis of the RII promoter did not show altered methylation patterns. The restriction endonuclease pattern of the RII gene was altered in two SCLC cell lines when digested with Sma 1. However, treatment with 5-aza-2′-deoxycytidine did not induce expression of RII mRNA. Our results indicate that in SCLC lack of RII mRNA is not commonly due to mutations and inactivation of RII transcription was not due to hypermethylation of the RII promoter or gene. Thus, these data show that in most cases of the SCLC cell lines, the RII gene and promoter is intact in spite of absent RII expression. However, the nature of the mutation found could suggest that it was caused by cigarette smoking. © 1999 Cancer Research Campaig

    Nanotools for Neuroscience and Brain Activity Mapping

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    Neuroscience is at a crossroads. Great effort is being invested into deciphering specific neural interactions and circuits. At the same time, there exist few general theories or principles that explain brain function. We attribute this disparity, in part, to limitations in current methodologies. Traditional neurophysiological approaches record the activities of one neuron or a few neurons at a time. Neurochemical approaches focus on single neurotransmitters. Yet, there is an increasing realization that neural circuits operate at emergent levels, where the interactions between hundreds or thousands of neurons, utilizing multiple chemical transmitters, generate functional states. Brains function at the nanoscale, so tools to study brains must ultimately operate at this scale, as well. Nanoscience and nanotechnology are poised to provide a rich toolkit of novel methods to explore brain function by enabling simultaneous measurement and manipulation of activity of thousands or even millions of neurons. We and others refer to this goal as the Brain Activity Mapping Project. In this Nano Focus, we discuss how recent developments in nanoscale analysis tools and in the design and synthesis of nanomaterials have generated optical, electrical, and chemical methods that can readily be adapted for use in neuroscience. These approaches represent exciting areas of technical development and research. Moreover, unique opportunities exist for nanoscientists, nanotechnologists, and other physical scientists and engineers to contribute to tackling the challenging problems involved in understanding the fundamentals of brain function

    Black race as a predictor of poor health outcomes among a national cohort of HIV/AIDS patients admitted to US hospitals: a cohort study

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    BACKGROUND: In general, the Human Immunodeficiency Virus/Acquired Immunodeficiency Syndrome (HIV/AIDS) population has begun to experience the benefits of highly active antiretroviral therapy (HAART); unfortunately, these benefits have not extended equally to Blacks in the United States, possibly due to differences in patient comorbidities and demographics. These differences include rates of hepatitis B and C infection, substance use, and socioeconomic status. To investigate the impact of these factors, we compared hospital mortality and length of stay (LOS) between Blacks and Whites with HIV/AIDS while adjusting for differences in these key characteristics. METHODS: The 1996-2006 National Hospital Discharge Surveys were used to identify HIV/AIDS patients admitted to US hospitals. Survey weights were incorporated to provide national estimates. Patients < 18 years of age, those who left against medical advice, those with an unknown discharge disposition and those with a LOS < 1 day were excluded. Patients were stratified into subgroups by race (Black or White). Two multivariable logistic regression models were constructed with race as the independent variable and outcomes (mortality and LOS > 10 days) as the dependent variables. Factors that were significantly different between Blacks and Whites at baseline via bivariable statistical tests were included as covariates. RESULTS: In the general US population, there are approximately 5 times fewer Blacks than Whites. In the present study, 1.5 million HIV/AIDS hospital discharges were identified and Blacks were 6 times more likely to be hospitalized than Whites. Notably, Blacks had higher rates of substance use (30% vs. 24%; P < 0.001), opportunistic infections (27% vs. 26%; P < 0.001) and cocaine use (13% vs. 5%; P < 0.001). Conversely, fewer Blacks were co-infected with hepatitis C virus (8% vs. 12%; P < 0.001). Hepatitis B virus was relatively infrequent (3% for both groups). Crude mortality rates were similar for both cohorts (5%); however, a greater proportion of Blacks had a LOS > 10 days (21% vs. 19%; P < 0.001). Black race, in the presence of comorbidities, was correlated with a higher odds of LOS > 10 days (OR, 95% CI = 1.20 [1.10-1.30]), but was not significantly correlated with a higher odds of mortality (OR, 95% CI = 1.07 [0.93-1.25]). CONCLUSION: Black race is a predictor of LOS > 10 days, but not mortality, among HIV/AIDS patients admitted to US hospitals. It is possible that racial disparities in hospital outcomes may be closing with time
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