Organic solvent treatment and physicochemical properties of nanoporous polymer–SBA-15 composite materials

Mesoporous polymer–silica composites are attractive new materials because these systems can combine the advantages of highly porous silica and the vast functional diversity of organic polymers in a single robust structure. This contribution deals with the effects of organic solvent treatment on the physicochemical properties of mesostructured polymer–SBA-15 silica nanocomposites. For this study, two distinct reference mesoporous nanocomposites were prepared using a previously reported surface-confined polymerization technique, e.g., poly(styrene)(PS)–SBA-15 composite and poly(2-hydroxyethyl methacrylate)(PHEMA)–SBA-15 composite. The resulting materials are treated either with chloroform or toluene under heating for a prolonged period of time (24 h). Both materials are characterized prior and after solvent treatment by nitrogen physisorption at −196 °C, thermogravimetry and Attenuated Total Reflection Infra-Red (ATR-IR) spectroscopy. In general, solvent stability is excellent for both types of composite, even for low cross-linking degree of the polymer. Our data reveal that a treatment of mesoporous PHEMA–SBA-15 with chloroform or toluene has a minor, but reproducible, effect on the composite material in terms of porosity. Here, a reorganization of the polymer layer–silica interface seems to occur to some extent, which is leading to slight variation of the intrawall porosity. As a consequence, an increase of the thermal stability is clearly observed, with, however, no marked difference in the mean mesopore diameter. On the other hand, the PS–SBA-15 composite treated with the same solvents shows higher specific surface area values and an improved homogeneity in terms of polymer coating compared to untreated materials, especially for composites synthesized using benzoyle peroxide as the polymerization initiator. However, no increase in thermal stability is observed in this case.     

Influence-enhanced scatterplots.

Describes several approaches to the data-analytic use of the influence function of the correlation coefficient. Some of these approaches make use of computer graphics, and others work with handmade plots. Computational algorithms for influence contours are discussed. (9 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Practical Note on One-Tailed Tests.

This article addresses some confusion over the use of one-tailed tests and provides practical advice as to their use gleaned from a 1968 lecture given by John Tukey. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Direct chromatographic determination of dissociation rate constants of ligand-receptor complexes: assessment of the interaction of noncompetitive inhibitors with an immobilized nicotinic acetylcholine receptor-based liquid chromatography stationary phase

A liquid chromatographic stationary phase containing immobilized membranes from a cell line expressing the alpha3beta4 subtype of the neuronal nicotinic acetylcholine receptor (nAChR) has been used to assess dissociation rate constants (kd) of 12 noncompetitive inhibitor-nAChR complexes. The pharmacological effects of the noncompetitive inhibitors, expressed as percent recovery of activity at 7 min and 4 h postexposure to the inhibitor, were also determined. The results demonstrate that the kd values correlated with the pharmacological effect and that this approach can be used to identify molecular structures associated with differences in kd values. The method can be adapted for use with membrane-bound receptors, ion channels, and transporters and represents a direct and facile technique for the assessment of dissociation rate constants (kd) of ligand-receptor complexes.     

MMP-7 and fcDNA Serum Levels in Early NSCLC and Idiopathic Interstitial Pneumonia: Preliminary Study

A non-invasive test to facilitate the diagnosis of non-small cell lung cancer (NSCLC) and idiopathic pulmonary fibrosis (IPF) is still not available and represents an important goal. Forty-eight patients with stage I NSCLC, 45 with IPF, 30 with other idiopathic interstitial pneumonias (IIPs) including idiopathic non-specific interstitial pneumonia (NSIP) and chronic hypersensitivity pneumonitis (HP), 35 with diffuse non-malignant disease and 30 healthy donors were enrolled onto the study. Free circulating (fc)DNA and MMP-7 levels were evaluated by Real Time PCR and ELISA, respectively. Median fcDNA levels were similar in NSCLC (127 ng/mL, range 23.6–345 ng/mL) and IPF (106 ng/mL, range 22–224 ng/mL) patients, and significantly lower in IIPs patients, in individuals with other diseases and in healthy donors (p < 0.05). Conversely, median MMP-7 values were significantly higher in IPF patients (9.10 ng/mL, range 3.88–19.72 ng/mL) than in those with NSCLC (6.31 ng/mL, range 3.38–16.36 ng/mL; p < 0.0001), NSIP (6.50 ng/mL, range 1.50–22.47 ng/mL; p = 0.007), other diseases (5.41 ng/mL, range 1.78–15.91, p < 0.0001) or healthy donors (4.35 ng/mL, range 2.45–7.23; p < 0.0001). Serum MMP-7 levels seem to be capable of distinguishing IPF patients from those with any other lung disease. fcDNA levels were similar in NSCLC and IPF patients, confirming its potential role as a biomarker, albeit non-specific, for the differential diagnosis of NSCLC.     

Discrepancies between VEGF ?1154 G>A Polymorphism Analysis Performed in Peripheral Blood Samples and FFPE Tissue

Single nucleotide polymorphisms (SNPs) may be associated with the response or toxicity to different types of treatment. Although SNP analysis is usually performed on DNA from peripheral blood, formalin fixed paraffin-embedded (FFPE) tissue is often used for retrospective studies. We analyzed VEGF (−2578C>A, −1498C>T, −1154G>A, −634C>G, +936C>T) and eNOS (+894G>T, −786T>C, VNTR (variable number of tandem repeats) 27bp intron 4) polymorphisms by direct sequencing or Real Time PCR in 237 patients with advanced colorectal cancer. Peripheral blood was used for 153 patients, whereas only FFPE tumor tissue was available for 84 patients. All SNP frequencies were in Hardy-Weinberg Equilibrium (HWE), with the exception of VEGF −1154, which was only in HWE in peripheral blood specimens. We therefore analyzed this SNP in DNA extracted from FFPE tumor tissue compared to FFPE healthy tissue and peripheral blood from 20 patients. Numerous heterozygous patients in peripheral blood DNA were homozygous for the A-allele in both tumor and healthy FFPE tissues. Our findings indicate that, although FFPE tissue might be a suitable specimen for genotyping, VEGF −1154 does not give reliable results on this type of material. As other SNPs may also have this limitation, genotype concordance should first be confirmed by comparing results obtained from FFPE and fresh sample analyses.     

Some multivariate displays for NAEP results.

The principal goal of graphic display is to ease access to complex information. Simple univariate displays are easy to understand but usually do not have the capability to transmit accurately the often complex structure of multivariate data. Multivariate displays were specifically designed for exactly this purpose. The National Assessment of Educational Progress (NAEP) generates data of a multivariate richness and complexity that defies accurate univariate transmission. The broad use and understanding of the information NAEP provides can be aided through the use of more suitable and evocative data displays. In this article, we demonstrate the limitations of univariate displays and suggest some multivariate displays that may enable us to understand, and thence communicate, what is contained in NAEP more fully. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Next generation wireless cellular networks: ultra-dense multi-tier and multi-cell cooperation perspective

Wireless Networks - The next generation wireless cellular network is aimed to address the demands of users and emerging use cases set by industries and academia for beyond 2020. Hence, The next...