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Shan G.,University of Quebec | Jin G.,Harbin Institute of Technology | Chen H.,Huazhong University of Science and Technology | Zhao M.,Wuhan University | And 4 more authors.
Journal of Hazardous, Toxic, and Radioactive Waste | Year: 2015

Flame-retardant polymer nanocomposites exhibiting remarkably improved flame-retardant and environmentally friendly properties have been widely utilized to replace traditional halogenated fire retardants. In this review, flame retardant mechanisms of polymer nanocomposites such as barrier effect, char formation, three-dimensional nanostructure, and radical trapping, are discussed to explain how nanomaterials can be incorporated in a polymer to reduce the polymer's flammability. Properties that are critical in governing the flame-retardant mechanisms of polymer nanocomposites are discussed in this review. Specifically, category, surface property, and concentration of nanomaterials are critical in affecting flame-retardant properties of polymer nanocomposites and are reviewed in detail. Nanocomposite categories, especially, silicates (clays), inorganic hydroxides, carbonaceous materials, metal oxides, polysilsequioxanes, and their combinations are well described. The use of synergism and surface modification of nanomaterials are important strategies for optimizing flame retardancy of polymer nanocomposites. The peak heat-release rate (HRR), the most important parameter for predicting fire hazard, is widely involved in this review. © 2015 American Society of Civil Engineers.

Trickey A.W.,INOVA Fairfax Hospital | Fox E.E.,Biostatistics Epidemiology Research Design Core | Del Junco D.J.,University of Texas Health Science Center at Houston | Ning J.,INOVA Fairfax Hospital | And 13 more authors.
Journal of Trauma and Acute Care Surgery | Year: 2013

BACKGROUND: Missing data are inherent in clinical research andmay be especially problematic for trauma studies. This study describes a sensitivity analysis to evaluate the impact ofmissing data on clinical risk prediction algorithms.Three blood transfusion predictionmodelswere evaluated using an observational trauma data set with valid missing data. METHODS: The PRospectiveObservationalMulticenterMajor Trauma Transfusion (PROMMTT) study included patients requiring one or more unit of red blood cells at 10 participating US Level I trauma centers from July 2009 to October 2010. Physiologic, laboratory, and treatment data were collected prospectively up to 24 hours after hospital admission. Subjects who received 10 or more units of red blood cells within 24 hours of admission were classified as massive transfusion (MT) patients. Correct classification percentages for three MT prediction models were evaluated using complete case analysis and multiple imputation. A sensitivity analysis for missing data was conducted to determine the upper and lower bounds for correct classification percentages. RESULTS: PROMMTT study enrolled 1,245 subjects.MTwas received by 297 patients (24%). Missing percentage ranged from 2.2% (heart rate) to 45%(respiratory rate). Proportions of complete cases used in theMTpredictionmodels ranged from 41%to 88%.Allmodels demonstrated similar correct classification percentages using complete case analysis and multiple imputation. In the sensitivity analysis, correct classification upper-lower bound ranges permodelwere 4%,10%, and 12%. Predictive accuracy for allmodels usingPROMMTTdatawas lower than reported in the original data sets. CONCLUSION: Evaluating the accuracy clinical prediction models with missing data can be misleading, especially with many predictor variables and moderate levels of missingness per variable. The proposed sensitivity analysis describes the influence of missing data on risk prediction algorithms. Reporting upper-lower bounds for percent correct classification may be more informative than multiple imputation, which provided similar results to complete case analysis in this study. Copyright © 2013 Lippincott Williams & Wilkins.

Poonawalla I.B.,Human Genetics and Environmental science | Goyal S.,Rutgers Cancer Institute of New JerseyNJ | Allicock M.,University of Texas at Dallas | Allicock M.,University of Texas Southwestern Medical Center | And 2 more authors.
Asian Pacific Journal of Cancer Prevention | Year: 2014

Background: Breast cancer incidence is increasing among South Asian migrants to the United States (US). However, their utilization of cancer screening services is poor. This study characterizes attitudes of South Asians towards breast health and screening in a community sample. Materials and Methods: A cross-sectional survey based on the Health Belief Model (HBM) was conducted among South Asians (n=124) in New Jersey and Chicago. The following beliefs and attitudes towards breast cancer screening were assessed-health motivation, breast self-examination confidence, breast cancer susceptibility and fear, and mammogram benefits and barriers. Descriptive statistics and Spearman rank correlation coefficients were computed for HBM subscales. Findings: Mean age of participants was 36 years with an average 10 years stay in the US. Most women strived to care for their health (3.82±1.18) and perceived high benefits of screening mammography (3.94±0.95). However, they perceived lower susceptibility to breast cancer in the future (2.30±0.94). Conclusions: Increasing awareness of breast cancer risk for South Asian women may have a beneficial effect on cancer incidence because of their positive attitudes towards health and breast cancer screening. This is especially relevant because South Asians now constitute one of the largest minority populations in the US and their incidence of breast cancer is steadily increasing.

Luu H.N.,Baylor College of Medicine | Amirian E.S.,Baylor College of Medicine | Chan W.,University of Texas Health Science Center at Houston | Beasley R.P.,Human Genetics and Environmental science | And 2 more authors.
Journal of Infectious Diseases | Year: 2012

Background.Little is known about the associations between CD4 + cell counts, human immunodeficiency virus (HIV) load, and human papillomavirus "low-risk" types in noncancerous clinical outcomes. This study examined whether CD4 + count and HIV load predict the size of the largest anal warts in 976 HIV-infected women in an ongoing cohort.Methods.A linear mixed model was used to determine the association between size of anal wart and CD4 + count and HIV load.Results.The incidence of anal warts was 4.15 cases per 100 person-years (95% confidence interval [CI], 3.83-4.77) and 1.30 cases per 100 person-years (95% CI, 1.00-1.58) in HIV-infected and HIV-uninfected women, respectively. There appeared to be an inverse association between size of the largest anal warts and CD4 + count at baseline; however, this was not statistically significant. There was no association between size of the largest anal warts and CD4 + count or HIV load over time.Conclusions.There was no evidence for an association between size of the largest anal warts and CD4 + count or HIV load over time. Further exploration on the role of immune response on the development of anal warts is warranted in a larger study. © 2011 The Author.

Medina M.A.,Baylor College of Medicine | Couturier J.,University of Texas Health Science Center at Houston | Feske M.L.,Human Genetics and Environmental science | Mahne A.E.,Baylor College of Medicine | And 8 more authors.
Journal of Leukocyte Biology | Year: 2012

Some human memory CD4+ T cells have cytotoxic functions best understood in the context of viral infections; however, their possible role in pathologic processes is understudied. The novel discovery that mitogenic CD28 antibodies induced proliferation and expansion of Tregs offered therapeutic promise for autoimmune disorders. However, the failed TGN1412 trial forced reassessment of this concept. As memory CD4+ T cells are known to produce toxic molecules, including granzyme B (GrzB) and FasL, we wondered whether mitogenic CD28 was able to induce these cytotoxic molecules. A commercially available mitogenic human CD28 mAb (clone ANC28.1) was used to determine whether mitogenic CD28 induces cytotoxic function from human memory CD4+ T cells. We found that stimulation of memory CD4+ T cells by ANC28.1, as well as by conventional costimulation (CD3/CD28 mAb), robustly induced enzymatically active GrzB, along with increased surface expression of FasL. These functional phenotypes were induced in association with increased expression of T cell activation markers CD69 and CD25, and elimination of target cells by ANC28.1-acti-vated memory CD4+ T cells involved both GrzB and FasL. Additionally, ANC28.1-activated memory CD4+ T cells caused disruption of epithelial cell monolayer integrity, which was partially mediated by GrzB. These findings reveal functions of memory CD4+ T cells previously unknown to be induced by mitogenic CD28, and suggest that these pathogenic mechanisms may have been responsible for some of the widespread tissue destruction that occurred in the TGN1412 trial recipients. © Society for Leukocyte Biology.

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