34 research outputs found
Nanostring-based multigene assay to predict recurrence for gastric cancer patients after surgery
10.1371/journal.pone.0090133PLoS ONE93-POLN
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Anodized titania processing and characterization to improve cell-materials interactions for load bearing implants
The objective of this study is to investigate in vitro cell-materials interactions using human osteoblast cells on anodized titanium. Titanium is a bioinert material and, therefore, gets encapsulated after implantation into the living body by a fibrous tissue that isolates them from the surrounding tissues. In this work, bioactive nonporous and nanoporous TiO2 layers were grown on commercially pure titanium substrate by anodization process using different electrolyte solutions namely (1) H3PO4, (2) HF and (3) H2SO4, (4) aqueous solution of citric acid, sodium fluoride and sulfuric acid. The first three electrolytes produced bioactive TiO2 films with a nonporous structure showing three distinctive surface morphologies. Nanoporous morphology was obtained on Ti-surfaces from the fourth electrolyte at 20V for 4h. Cross-sectional view of the nanoporous surface reveals titania nanotubes of length 600 nm. It was found that increasing anodization time initially increased the height of the nanotubes while maintaining the tubular array structure, but beyond 4h, growth of nanotubes decreased with a collapsed array structure. Human osteoblast (HOB) cell attachment and growth behavior were studied using an osteoprecursor cell line (OPC 1) for 3, 7 and 11 days. Colonization of the cells was noticed with distinctive cell-to-cell attachment on HF anodized surfaces. TiO2 layer grown in H2SO4 electrolyte did not show significant cell growth on the surface, and some cell death was also noticed. Good cellular adherence with extracellular matrix extensions in between the cells was noticed for samples anodized with H3PO4 electrolyte and nanotube surface. Cell proliferation was excellent on anodized nanotube surfaces. An abundant amount of extracellular matrix (ECM) between the neighboring cells was also noticed on nanotube surfaces with filopodia extensions coming out from cells to grasp the nanoporous surface for anchorage. To better understand and compare cell-materials interactions, anodized nanoporous sample surfaces were etched with different patterns. Preferential cell attachment was noticed on nanotube surfaces compared to no cells on etched patterned surface. Cell adhesions and differentiation were more pronounced with vinculin protein and alkaline phosphatase, respectively, on anodized surfaces. MTT assays showed increase in living cell density and higher proliferation on H3PO4, HF and nanotube surfaces. When anodized surfaces were compared for cell materials interaction, it was noticed that each of the surfaces has different surface properties that led to variations in cellmaterials interactions. It was clear that rough surface morphology, high surface energy, and low value of the contact angles were important factors for better cell materials interaction. Mineralization study was done in simulated body fluid (SBF) with ion concentration nearly equal to human blood plasma to further understand biomimetic apatite deposition behavior. Similar to cell-materials interaction, variation in mineral deposition behavior was also noticed for films grown with different electrolytes. These results clearly show that nonporous titania in H3PO4, HF electrolytes and nanotubes can significantly increase biocompatibility of Ti implants, which has the potential to reduce the healing time and increase in vivo lifetime for these implants
ANODIZED TITANIA: PROCESSING AND CHARACTERIZATION TO IMPROVE CELL-MATERIALS INTERACTIONS FOR LOAD BEARING IMPLANTS By
The members of the Committee appointed to examine the dissertation o
Modelling the number of antenatal care visits in Bangladesh to determine the risk factors for reduced antenatal care attendance
2020 Bhowmik et al. The existence of excess zeros in the distribution of antenatal care (ANC) visits in Bangladesh raises the research question of whether there are two separate generating processes in taking ANC and the frequency of ANC. Thus the main objective of this study is to identify a proper count regression model for the number of ANC visits by pregnant women in Bangladesh covering the issues of overdispersion, zero-inflation, and intra-cluster correlation with an additional objective of determining risk factors for ANC use and its frequency. The data have been extracted from the nationally representative 2014 Bangladesh Demographic and Health Survey, where 22% of the total 4493 women did not take any ANC during pregnancy. Since these zero ANC visits can be either structural or sampling zeros, two-part zero-inflated and hurdle regression models are investigated along with the standard onepart count regression models. Correlation among response values has been accounted for by incorporating cluster-specific random effects in the models. The hurdle negative binomial regression model with cluster-specific random intercepts in both the zero and the count part is found to be the best model according to various diagnostic tools including likelihood ratio and uniformity tests. The results show that women who have poor education, live in poor households, have less access to mass media, or belong to the Sylhet and Chittagong regions are less likely to use ANC and also have fewer ANC visits. Additionally, women who live in rural areas, depend on family members\u27 decisions to take health care, and have unintended pregnancies had fewer ANC visits. The findings recommend taking both cluster-specific random effects and overdispersion and zero-inflation into account in modelling the ANC data of Bangladesh. Moreover, safe motherhood programmes still need to pay particular attention to disadvantaged and vulnerable subgroups of women
On exploring and ranking risk factors of child malnutrition in Bangladesh using multiple classification analysis
BACKGROUND: Logistic regression analysis is widely used to explore the determinants of child malnutrition status mainly for nominal response variable and non-linear relationship of interval-scale anthropometric measure with nominal-scale predictors. Multiple classification analysis relaxes the linearity assumption and additionally prioritizes the predictors. Main objective of the study is to show how does multiple classification analysis perform like linear and logistic regression analyses for exploring and ranking the determinants of child malnutrition. METHODS: Anthropometric data of under-5 children are extracted from the 2011 Bangladesh Demographic and Health Survey. The analysis is carried out considering several socio-economic, demographic and environmental explanatory variables. The Height-for-age Z-score is used as the anthropometric measure from which malnutrition status (stunting: below −2.0 Z-score) is identified. RESULTS: The fitted multiple classification analysis models show similar results as linear and logistic models. Children age, birth weight and birth interval; mother’s education and nutrition status; household economic status and family size; residential place and regional settings are observed as the significant predictors of both Height-for-age Z-score and stunting. Child, household, and mother level variables have been ranked as the first three significant groups of predictors by multiple classification analysis. CONCLUSIONS: Detecting and ranking the determinants of child malnutrition through Multiple classification analysis might help the policy makers in priority-based decision-making. TRIAL REGISTRATION: “Retrospectively registered
Studies on the structure of 7α-hydroxytaraxerol
2129-2131The proposed structure of the natural
product 7α-hydroxytaraxerol (D-friedoolean-14-en-3β,
7α-diol)
1 has been established by its synthesis from a known compound, multiflorenol
(D : C-friedoolean-7-en-3β-ol) 2
Additional file 1: Table S1. of On exploring and ranking risk factors of child malnutrition in Bangladesh using multiple classification analysis
Description of data: Distribution of mothers by household (HH) wealth status, motherâs highest level education status and residential place, BDHS 2011. (PDF 185 kb
Modelling the number of antenatal care visits in Bangladesh to determine the risk factors for reduced antenatal care attendance
The existence of excess zeros in the distribution of antenatal care (ANC) visits in Bangladesh raises the research question of whether there are two separate generating processes in taking ANC and the frequency of ANC. Thus the main objective of this study is to identify a proper count regression model for the number of ANC visits by pregnant women in Bangladesh covering the issues of overdispersion, zero-inflation, and intra-cluster correlation with an additional objective of determining risk factors for ANC use and its frequency. The data have been extracted from the nationally representative 2014 Bangladesh Demographic and Health Survey, where 22% of the total 4493 women did not take any ANC during pregnancy. Since these zero ANC visits can be either structural or sampling zeros, two-part zero-inflated and hurdle regression models are investigated along with the standard one-part count regression models. Correlation among response values has been accounted for by incorporating cluster-specific random effects in the models. The hurdle negative binomial regression model with cluster-specific random intercepts in both the zero and the count part is found to be the best model according to various diagnostic tools including likelihood ratio and uniformity tests. The results show that women who have poor education, live in poor households, have less access to mass media, or belong to the Sylhet and Chittagong regions are less likely to use ANC and also have fewer ANC visits. Additionally, women who live in rural areas, depend on family members' decisions to take health care, and have unintended pregnancies had fewer ANC visits. The findings recommend taking both cluster-specific random effects and overdispersion and zero-inflation into account in modelling the ANC data of Bangladesh. Moreover, safe motherhood programmes still need to pay particular attention to disadvantaged and vulnerable subgroups of women
Synthesis of 25-oxygenated D: A-friedooleananes: Part V<sup>†</sup> — Conversion of putranjivadione (D: A-friedoolean-3, 7-dione) to 25-formyl D: A-friedoolean-3-one
1960-1961Structure of the natural product 25-formyl-D:A-friedoolean-3-one
1 has been established by its synthesis from putranjivadione 2. Compound
2 is converted into 7β, 25-oxido-D:A-friedoolean-
3β-ol 4 which on treatment with
lithium in ethylenediamine yields D:A-friedoolean-3β, 25-diol 5 as one of
the products.5 on oxideation with CrO3 in pyridine affords 1