13 research outputs found
Expanding Pore Size of Al-BDC Metal–Organic Frameworks as a Way to Achieve High Adsorption Selectivity for CO<sub>2</sub>/CH<sub>4</sub> Separation
The mesostructured Al-BDC metal–organic
frameworks (MOFs)
with an average pore size of 2.58 nm were prepared via a simplified
washing and drying process and applied to the separation of CO<sub>2</sub>/CH<sub>4</sub> mixtures. The adsorption equilibrium and thermodynamics
of CH<sub>4</sub> and CO<sub>2</sub> were studied in the dynamic processes
by the volumetric–chromatographic and inverse gas chromatographic
(IGC) methods. The experiments represent that the Al-BDC MOF with
large pore size has a much higher CO<sub>2</sub>/CH<sub>4</sub> selectivity
of ca. 24 at 303 K in the pressure range 0–1.0 MPa and therefore
appears to be a good candidate for the separation of CH<sub>4</sub> from CO<sub>2</sub>. The initial heats of adsorption of CH<sub>4</sub> and CO<sub>2</sub> on the mesostructured Al-BDC MOFs were determined
to be 11.5 and 25.2 kJ mol<sup>–1</sup> by the IGC method,
respectively, which are significantly reduced by ca. 25% compared
with that on the microporous Al-BDC MOFs. The results indicate that
the expanded pore size not only greatly increases the selectivity
of CO<sub>2</sub> adsorption over CH<sub>4</sub> but also reduces
the adsorption heat, revealing that it should be the desired method
to obtain a satisfactory absorbent for CO<sub>2</sub>/CH<sub>4</sub> separation
A Prognostic Model of Triple-Negative Breast Cancer Based on miR-27b-3p and Node Status
<div><p>Objective</p><p>Triple-negative breast cancer (TNBC) is an aggressive but heterogeneous subtype of breast cancer. This study aimed to identify and validate a prognostic signature for TNBC patients to improve prognostic capability and to guide individualized treatment.</p><p>Methods</p><p>We retrospectively analyzed the prognostic performance of clinicopathological characteristics and miRNAs in a training set of 58 patients with invasive ductal TNBC diagnosed between 2002 and 2012. A prediction model was developed based on independent clinicopathological and miRNA covariates. The prognostic value of the model was further validated in a separate set of 41 TNBC patients diagnosed between 2007 and 2008.</p><p>Results</p><p>Only lymph node status was marginally significantly associated with poor prognosis of TNBC (<i>P</i> = 0.054), whereas other clinicopathological factors, including age, tumor size, histological grade, lymphovascular invasion, P53 status, Ki-67 index, and type of surgery, were not. The expression levels of miR-27b-3p, miR-107, and miR-103a-3p were significantly elevated in the metastatic group compared with the disease-free group (<i>P</i> value: 0.008, 0.005, and 0.050, respectively). The Cox proportional hazards regression analysis revealed that lymph node status and miR-27b-3p were independent predictors of poor prognosis (<i>P</i> value: 0.012 and 0.027, respectively). A logistic regression model was developed based on these two independent covariates, and the prognostic value of the model was subsequently confirmed in a separate validation set. The two different risk groups, which were stratified according to the model, showed significant differences in the rates of distant metastasis and breast cancer-related death not only in the training set (<i>P</i> value: 0.001 and 0.040, respectively) but also in the validation set (<i>P</i> value: 0.013 and 0.012, respectively).</p><p>Conclusion</p><p>This model based on miRNA and node status covariates may be used to stratify TNBC patients into different prognostic subgroups for potentially individualized therapy.</p></div
Univariate and multivariate Cox proportional hazards regression analysis to evaluate the independent prognostic value of clinicopathological parameters and miRNAs in relation to distant metastasis.
<p>HR: hazard ratio; LN: lymph node.</p
Prognostic performance of the prediction model in a validation cohort of 41 TNBC patients.
<p>A risk score was assigned to each patient as calculated by the prediction model. Based on the risk score, the patients were stratified into either the low-risk group or the high-risk group. Kaplan-Meier analysis and log-rank tests were used to determine the significant differences in survival between groups. (A) Differences in distant metastasis-free survival between low-risk and high-risk groups. (B) Differences in overall survival between low-risk and high-risk groups.</p
Kaplan-Meier analysis to evaluate the statistical power of the predictive model, based on miR-27b-3p and node status, in predicting the distant metastasis-free survival and overall survival of 58 TNBC patients in the training set.
<p>According to the prediction model, each patient was assigned to a low-risk or high-risk group. Significant differences in survival between groups were determined by log-rank analysis. (A) Application of the model to predict the distant metastasis outcomes of TNBC patients. (B) Application of the model to predict the overall survival of TNBC patients.</p
Expression profile comparisons of the five selected miRNAs between 31 distant metastases patients and 27 disease-free patients in the training set by the Mann–Whitney U test.
<p>CT: the threshold cycle to detect fluorescence; ΔCT = CT<sub>miRNA</sub>−CT<sub>U6</sub>, ΔΔCT = ΔCT<sub>poor prognosis</sub>−ΔCT<sub>good prognosis</sub>.</p><p>Patients who developed distant metastasis as first event within 5 years after removal of the primary tumor were considered to have poor prognosis, whereas patients who remained disease free for a minimum of 5 years were defined as having good prognosis. Fold change represented the miRNA expression level of poor prognosis group versus good prognosis group, and was calculated using the equation RQ = 2<sup>−ΔΔCT</sup><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0100664#pone.0100664-Livak1" target="_blank">[28]</a>.</p
Univariate analysis of clinicopathological characteristics and miR-27b-3p expression with distant metastasis of TNBC in a validation set.
<p>HR: hazard ratio; y: years; CI: confidence interval; LVI: lymphovascular invasion; N/A: not applicable.</p
Clinicopathological characteristics and association with distant metastasis of TNBC in the training set.
<p>HR: hazard ratio; y: years; CI: confidence interval; LVI: lymphovascular invasion; MRM: modified radical mastectomy; BCS: breast conserving surgery; N/A: not applicable.</p><p>*Ki-67 index threshold of 14% was chosen according to the St. Gallen Consensus 2013 <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0100664#pone.0100664-Goldhirsch1" target="_blank">[29]</a>.</p
Molecular Structure and Physicochemical Properties of Starches from Rice with Different Amylose Contents Resulting from Modification of OsGBSSI Activity
OsGBSSI,
encoded by the <i>Waxy</i> (<i>Wx</i>) gene, is
the key enzyme in the synthesis of amylose chains. Transgenic
rice lines with various GBSSI activities were previously developed
via site-directed mutagenesis of the <i>Wx</i> gene in the
glutinous cultivar Guanglingxiangnuo (GLXN). In this study, grain
morphology, molecular structure, and physicochemical properties were
investigated in four transgenic lines with modified OsGBSSI activity
and differences in amylose content. A milky opaque appearance was
observed in low- and non-amylose rice grains due to air spaces in
the starch granules. Gel permeation chromatography (GPC) and high-performance
anion-exchange chromatography (HPAEC) analyses showed that although
OsGBSSI can synthesize intermediate and extra-long amylopectin chains,
it is mainly responsible for the longer amylose chains. Amylose content
was positively correlated with trough viscosity, final viscosity,
setback viscosity, pasting time, pasting temperature, and gelatinization
temperature and negatively with gel consistency, breakdown viscosity,
gelatinization enthalpy, and crystallinity. Overall, the findings
suggest that OsGBSSI may be also involved in amylopectin biosynthesis,
in turn affecting grain appearance, thermal and pasting properties,
and the crystalline structure of starches in the rice endosperm
BRAF V600E and TERT Promoter Mutations in Papillary Thyroid Carcinoma in Chinese Patients
<div><p>Background</p><p>The BRAF V600E and telomerase reverse transcriptase (TERT) promoter mutations have been reported in papillary thyroid carcinoma (PTC). The aim of this retrospective cross-sectional study was to add further information regarding the prevalence of the BRAF V600E and TERT promoter mutations in Chinese PTC and their clinicopathological associations.</p><p>Methods</p><p>We detected the BRAF V600E mutation and TERT promoter mutations in 455 Chinese PTC patients and analyzed the association of these mutations with several clinicopathological features.</p><p>Results</p><p>The BRAF V600E mutation was detected in 343 (75.4%) of 455 cases and was significantly associated with older age (p<0.001) and conventional subtype (p = 0.003). TERT promoter mutations were detected in 19 (4.4%) of 434 PTCs and were associated with older age (p<0.001), larger tumor size (p = 0.024), and advanced TNM stage(p<0.001). Of the 19 patients that were positive for TERT promoter mutations, 18 (94.7%) also harbored the BRAF V600E mutation.</p><p>Conclusion</p><p>We determined the prevalence and clinicopathological associations of BRAF V600E and TERT promoter mutations in Chinese PTC patients. TERT promoter mutations but not the BRAF V600E mutation were associated with more advanced TNM stage upon diagnosis.</p></div