Association between Serum Soluble CD154 Levels and Mortality in Patients with Malignant Middle Cerebral Artery Infarction

Background: CD154 and its soluble counterpart (sCD154) are proteins of the tumor necrosis factor (TNF) family and exhibit proinflamatory and procoagulant properties. Higher circulating sCD154 levels have been found in ischemic stroke patients than in controls. However, the association between circulating sCD154 levels and mortality in ischemic stroke patients has not been reported, and was the focus of this study. Methods: This was a multicenter, observational and prospective study carried out in six Spanish Intensive Care Units. We measured serum sCD154 from 50 patients with severe malignant middle cerebral artery infarction (MMCAI), defined as Glasgow Coma Scale (GCS) lower than 9, at the moment of the severe MMCAI diagnosis and from 50 healthy controls. The end-point of the study was 30-day mortality. Results: We found higher serum sCD154 levels in patients with severe MMCAI than in healthy controls (p < 0.001). We found higher serum sCD154 levels (p < 0.001) in non-surviving (n = 26) than in surviving MMCAI patients (n = 24). Multiple binomial logistic regression analysis showed that serum sCD154 levels >1.41 ng/mmL were associated with 30-day mortality (OR = 10.25; 95% CI = 2.34–44.95; p = 0.002). Conclusions: The new more important finding of our study was that serum sCD154 levels in MMCAI patients were associated with mortality.     

Evolution of the chemical and morphological changes of HDPE when subjected to digestion in a strong acid medium

High‐density polyethylene (HDPE) is the polymer most used for geomembranes, and one of the tests to determine its applicability is its long term resistance to oxidation. In this sense, this work focuses on the study of the chemical and morphological changes that PE films may experiment when subjected to digestion in nitric acid, simulating the severe ambient conditions of a landfill. The effect of digestion of HDPE, on its chemical and morphological structure, was evaluated. It was observed that the molecular weight of HDPE decreases, forming acid and nitro groups, as the time of digestion increases. Also, the oxidative degradation first produced a bimodal MW distribution, but as the time of strong acid treatment increases, a trimodal MW distribution appears, at lower molecular weights. Finally, as time of digestion continued, a bimodal MW distribution appears again, but at much lower molecular weights. The crystal size of the treated HDPE is directly related to the HDPE molecular weight, that is, as time of digestion increases, the molecular weight decreases and the crystal size decreases. In addition, the heterogeneity of molecular weights, such as bimodal and trimodal distributions, and the presence of chemical groups other than the normal ? CH₂? strings of pure PE produced defects in the unit cell parameters a and b . © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Direct relationships between volume variations at macro and nanoscale in epoxy systems. PALS/PVT measurements

The free volume in epoxy systems fully cured with aminic hardeners having different chemical structures was studied by means of positron annihilation lifetimes spectroscopy. The results are compared with those obtained from the analysis of the macroscopic specific volume changes by using pressure-volume-temperature experimental technique. An excellent correlation between the volumes measured at macro and nanoscales was found. From this fact, it can be asserted that the variation of the specific volume is mainly controlled by the variation in the average size of sub-nanometer size local free volumes, which are fixed by the chemical structure of hardener in fully crosslinked epoxy networks. These results give the first evidence of the direct relation existing between macro and nanoscales in thermosetting networks.     

Lignin–polypropylene composites. II. Plasma modification of kraft lignin and particulate polypropylene

Indulin kraft lignin and polypropylene were subjected to plasma treatments in a rotating electrodeless plasma reactor at 13.56 MHz radio frequency, with the goal of improving the strength properties of the composites made from these materials. It was shown that efficient surface modification could be achieved by these plasma treatments, avoiding long reaction times and large volumes of reactants for modification by conventional wet chemistry. SiCl₄‐plasma treatments of lignin at 100 and 200 W resulted in silicon implantation in the range of 4–10% that depended on the treatment time. However, the effect of power in the treatments was minimal, given that changes in silicon implantation were not observed for changes in this parameter. SiCl₄‐plasma treatment of polypropylene at 80 W, 1 and 10 min, resulted in silicon implantation in the order of 10–15%, for the two different treatment times, showing that low power and short treatment times were sufficient to significantly alter the polypropylene surface. However at high power (250 W), the longer treatment time of polypropylene apparently led to formation of oligohalosilanes. Other plasma treatments in the rotating reactor such as plasma‐induced copolymerization of acryloyl chloride on both lignin and polypropylene, and plasma‐state polymerization of acryloyl chloride on polypropylene under pulsing conditions, resulted in thin film depositions. Evaluation of composites from these treated materials is described in the next contribution (Part III) from this series. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1920–1926, 2004     

Fatty Acid Profiles in Sunflower Grains During Storage in Different Environments

This study aimed to evaluate the fatty acid profiles of sunflower oil extracted from hybrid grains produced and stored in different environments. The trials were conducted in Teresina (Piauí), Vilhena (Rondônia), and Jaguariúna (São Paulo) in randomized complete block design with 4 replicates. After harvesting, grains from 1 high oleic and 3 traditional hybrids were packed in kraft paper bags and stored in a covered shed and in a cold chamber up to 12 months. The fatty acid profiles were determined by gas chromatography after 0, 4, 8, and 12 months of storage. Analyses of variance were conducted in a split‐plot design, with hybrids being considered as whole plots and storage times as subplots. Tukey's test was performed to compare hybrids and regression analyses for storage times. The initial fatty acid profile of the grains of the same hybrid varied depending on the production location. The grain storage of high oleic and traditional sunflower hybrids during 12 months in covered shed and in cold chamber resulted in little changes in oil fatty acid profiles, regardless of the initial contents. These changes occurred only for linoleic and palmitic acids.     

Physicochemical properties and antimicrobial activity of biocompatible carboxymethylcellulose‐silver nanoparticle hybrids for wound dressing and epidermal repair

Skin loss can be caused by accident, burn, trauma, chronic wounds, and diseases, which is severely aggravated by multidrug‐resistant bacterial infections. Soft hybrids based on biopolymers combined with silver nanoparticles (AgNPs) have potential applications as wound dressing supports and skin tissue repair. Thus, our study focused on the design, green synthesis, and comprehensive characterization of carboxymethyl cellulose (CMC–AgNP) nanocomposites for producing hydrogel membranes, with tunable physicochemical properties, cytocompatibility, and biocidal activity for potential application as wound dressing and skin repair. These nanocomposites were prepared using CMC with two degrees of carboxymethylation, distinct concentrations of citric acid (CA) crosslinker, and AgNPs by in situ chemical reduction, forming hybrid membranes by the solvent casting method. The results demonstrated that superabsorbent hydrogels were produced with swelling and degradation behaviors dependent on the concentration of CA crosslinker, degree of carboxymethylation of CMC, and content of AgNP in the matrices. Moreover, the Fourier transform infrared spectroscopy analysis evidenced that the CMC functional groups (e.g., ? COOH and ? OH) were directly involved in the chemical reactions for the formation of AgNPs and hydrogel crosslinking pathway. These nanocomposites were cytocompatible using in vitro 3‐(4,5‐dimethyl‐2‐thiazolyl)‐2,5‐diphenyltetrazolium bromide cell viability assay with of human embryonic kidney cells. Conclusively, the CMC–AgNP nanohybrids demonstrated to be simultaneously non‐toxic combined with highly effective antibacterial activity against gram‐positive multi‐resistant wound/skin pathogens (Staphylococcus aureus) and moderate effect towards gram‐negative strains (Escherichia coli and Pseudomonas aeruginosa). © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45812.     

Understanding the Rate‐Limiting Step of Glycogenolysis by Using QM/MM Calculations on Human Glycogen Phosphorylase

Liver glycogen phosphorylase (GP) is a key enzyme for human health, as its increased activity is associated with type 2 diabetes. The GP catalytic mechanism has been explored by quantum mechanics/molecular mechanics (QM/MM) methods. Herein, we propose a mechanism that proceeds by three steps: 1) it begins with transfer of a hydrogen atom from the phosphate group of the pyridoxal 5′‐phosphate (HPO₄^2?‐PLP) cofactor to the phosphate substrate; 2) the glycosidic linkage is then cleaved through protonation of the glycosidic oxygen atom by a hydroxy group of the inorganic phosphate group; and 3) an oxygen atom of the phosphate performs a nucleophilic attack on the anomeric carbon atom of glucose, concomitant with the return of a proton from phosphate to PO₄^3?‐PLP, which finally leads to formation of the glucose‐1‐phosphate product and recovers the initial state of the PLP cofactor. The glycosidic bond cleavage and nucleophilic attack from the phosphate group to the glycosyl molecule have the highest activation free energies. The structural properties of the hereby characterized transition states could be very useful in structure‐based drug design studies against liver GP.     

Poly(lactic acid)/poly(3‐hexylthiophene) composite nanofiber fabrication for electronic applications

Fibers of the biopolymer poly(lactic acid) (PLA) and the p‐type semiconducting polymer poly(3‐hexylthiophene) (P3HT) were fabricated using the electrospinning technique at low PLA concentration (5 wt%) in CHCl₃. The fibers were several millimeters long and had diameters in the range 100 nm–4 µm. Nanofibers containing 63%/37% of PLA/P3HT were electroactive, and therefore were used to construct p–n diodes whose ideality parameter was 2.4 and rectification (on/off) ratio was 400 at ±1 V. These diodes were also able to sense UV radiation and remain operable with an increase in the on/off ratio and a lowering of the turn‐on voltage. By fabricating reusable and low‐cost multifunctional diodes from PLA/P3HT, the applications of PLA as a biocompatible and biodegradable polyester are expanded to include electronic device fabrication with low environmental impact. © 2016 Society of Chemical Industry     

Quantification of soybean oil ethanolysis with <Superscript>1</Superscript>H NMR

In this study, proton NMR spectroscopy (200 MHz) was used for quantifying the content of ethyl esters in known mixtures of soybean oil and ethyl soyate (biodiesel). For this purpose, the peak areas of ester ethoxy and glycerol methylenic peaks in the region of 4.05–4.40 ppm were measured and a calibration plot of the respective peak areas vs. the known composition of the oil/ethyl ester mixtures was used. The transesterification values determined in this way were compared with viscosity and total glycerol determinations and a good correlation was obtained. Therefore, for routine analysis, the conversion (in %) of oil to ethyl esters was determined. The methodology presented in this work proved to be quicker and simpler than others reported in the literature, such as GC and/or HPLC.     

Ionic liquid gated poly(triaryl amine) thin film field effect transistor

A poly(triaryl amine) thin film field effect transistor was investigated in air with ionic liquid (IL) gating for the first time. The transistor retained a high-on/off ratio of ~700 and mobility of ~10⁻² cm²/V-s. When compared to a transistor based on the conducting polymer polyaniline under similar operating conditions, it was found to exhibit superior performance. Significantly low-operating voltages (±1 V) enhances the possibility of its use in organic electronics. The device was successfully tested for binary operation, and we demonstrate its suitability for use in low-power consumption electronic circuits.