Dielectric,mechanical and transport properties of bisphenol A polycarbonate/graphene nanocomposites prepared by melt blending

Nanocomposites based on polycarbonate (PC) and different amounts of untreated graphene nanoplatelets (GnP) (from 1 to 7 wt %) were prepared by melt blending. The nanocomposites were thoroughly characterized employing the following techniques: broad band dielectric spectroscopy, thermally stimulated depolarization currents, differential scanning calorimetry, tensile testing, dynamic mechanical thermal analysis, and water vapor, carbon dioxide and oxygen permeability measurements. The presence of a MWS relaxation mode indicated the accumulation of electrical charges trapped at the interfaces of the polycarbonate with graphene 2D platelets. The addition of GnP produced nanocomposite materials with enhanced mechanical and barrier properties. The melt mixed PC/graphene nanocomposites prepared here exhibit well‐balanced properties, even though unmodified graphene nanoplatelets were used. In addition, the nanocomposites were obtained by a single extrusion process, which is easily scalable for industrial applications. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44654.     

Successful outcome of a left ventricular free wall rupture in a community hospital: case report

Rupture of the myocardium in the setting of acute myocardial infarction has a universally grim prognosis. The time that elapses between diagnosis and definitive therapy is the most critical determinant of the patient's outcome when death is not instantaneous. Survivors of this catastrophic event have not been frequently reported. We present a case of free wall left ventricular rupture in a patient with an acute myocardial infarction hospitalized in the Cardiac Care Unit of a small community hospital. The patient was successfully transferred to the referral institution for surgery. Rapid diagnosis, primary bedside therapy, and utilization of new surgical techniques helped obtain a good outcome.     

Does Anyone Know?

Comments on the article by W. B. Weimer (see record 1973-22081-001) regarding his discussion of Platonic-Aristotelian differences. The comments appears in poem form. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Deoxynivalenol in barley samples from Uruguay

A survey of the natural occurrence of deoxynivalenol (DON) in barley harvested in Uruguay from 1996 to 2002 was conducted. A total of 292 samples were analyzed for DON by an immunochemical method using inmunoaffinity columns and fluorimetric detection. Between 26 and 100% of the samples were positive for DON while mean DON contents varied between the quantification limit (500 mug/kg) to 6349 mug/kg. Annual maximum levels in individual samples ranged from 1900 mug/kg to 10,000 mug/kg. The mean DON contents were similar from 1996 to 1999 increasing markedly from 2000 to 2002. The percentage of the samples with DON were highest in 1997, 2000, 2001 and 2002 (67, 90, 100 and 100%) as was the accumulated precipitation during the flowering period. A positive correlation between DON levels and precipitation was seen. These results suggest that monitoring for DON barley crops, particularly in years with heavy rainfall during the flowering period, must be regularly performed.     

In Peripheral Blood Mononuclear Cells Helicobacter pylori Induces the Secretion of Soluble and Exosomal Cytokines Related to Carcinogenesis

Helicobacter pylori promotes the secretion of cytokines that regulate inflammation and carcinogenesis. Immune cells secrete cytokines into the extracellular medium or packaged in exosomes. The objective of this study was to analyze the profile of soluble and exosomal cytokines that were secreted by human peripheral blood mononuclear cells (PBMCs) that were infected with H. pylori and to build a network of interaction between cytokines and cellular proteins. PBMCs were obtained by density gradient centrifugation and infected with H. pylori for 24 h. The infection was verified by immunofluorescence and Western blot for CagA. The exosomes were obtained from culture supernatant by ultracentrifugation and characterized by transmission electron microscopy, particle size analysis, and Western blot for CD9 and CD81. Cytokines were quantified using a multiplex immunoassay in the culture supernatant, intact exosomes, and lysed exosomes. H. pylori adheres to lymphocytes and translocates CagA. In PBMCs, H. pylori induces an increase in the soluble and exosomal IL-1β, IL-6, TNF-α, IL-10, IL-17A, IL-21, and IL-22. The protein–protein interaction (PPI) network shows that soluble and exosomal cytokines interact with proteins that participate in signaling pathways such as NF-κB, MAPK, PI3K-Akt, Jak-STAT, FoxO, and mTOR, that are related to carcinogenesis; moreover, TNF-α had the highest number of interactions. Cytokine-loaded exosomes represent another means of intercellular communication that is activated by H. pylori to stimulate inflammation, carcinogenesis, or cancer progression. Cytokine-loaded exosomes are likely to be associated with extragastrointestinal diseases of inflammatory origin.     

Evidence-based parent training and family interventions for school behavior change.

In this article the guidelines of the Evidence-Based Interventions in School Psychology Task Force were used to evaluate the efficacy of parent training and family intervention for changing children's school behavior. Nineteen parent training and five family intervention studies that were conducted in schools, had a school treatment component, or included measurement of school change were identified and coded. Results found one parent training program and one family intervention to be proven efficacious across two randomized clinical trials. Several family interventions were probably efficacious or promising. Despite the established link between the family environment and school behavior, parent training and family interventions are uncommon in schools, and clinic-based treatment studies infrequently measure generalization of parent and family interventions to the school setting. Future researchers are encouraged to address these limitations and to include samples representative of the diversity of the public schools in family-focused intervention studies. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Synthesis, structural characterization, and pro-apoptotic activity of 1-indanone thiosemicarbazone platinum(II) and palladium(II) complexes: potential as antileukemic agents

In the search for alternative chemotherapeutic strategies against leukemia, various 1‐indanone thiosemicarbazones, as well as eight novel platinum(II) and palladium(II) complexes, with the formula [MCl₂(HL)] and [M(HL)(L)]Cl, derived from two 1‐indanone thiosemicarbazones were synthesized and tested for antiproliferative activity against the human leukemia U937 cell line. The crystal structure of [Pt(HL1)(L1)]Cl^.2M eOH, where L1=1‐indanone thiosemicarbazone, was solved by X‐ray diffraction. Free thiosemicarbazone ligands showed no antiproliferative effect, but the corresponding platinum(II) and palladium(II) complexes inhibited cell proliferation and induced apoptosis. Platinum(II) complexes also displayed selective apoptotic activity in U937 cells but not in peripheral blood monocytes or the human hepatocellular carcinoma HepG2 cell line used to screen for potential hepatotoxicity. Present findings show that, in U937 cells, 1‐indanone thiosemicarbazones coordinated to palladium(II) were more cytotoxic than those complexed with platinum(II), although the latter were found to be more selective for leukemic cells suggesting that they are promising compounds with potential therapeutic application against hematological malignancies.     

Molecular dynamics and crystallization kinetics in PSMA14/PCL blends

The effect of blending poly(styrene-co-maleic anhydride) with 14 mol% MA (PSMA14) with poly(?-caprolactone) (PCL) is studied by calorimetry, X-ray diffraction, dielectric techniques, and microscopy. Variations in PCL crystallization, melting temperatures and crystallinity degree were observed. Additionally, the presence of a wide and asymmetric enthalpic step, whose position follows Fox predictions, demonstrates miscibility between the blend components. This is in agreement with the interlamellar location of PSMA14. Thermally stimulated depolarization techniques evidenced two segmental dynamics, with distinct compositional variations due to the local differences in composition perceived by each component as a consequence of chain connectivity. The two effective glass transition temperatures vary with composition, in agreement with the self-concentration model predictions when using the Kuhn's segment length for each component. From isothermal crystallizations a marked depression of the PCL equilibrium melting point is observed in the blends together with an increase in the half-crystallization times, τ^1/2, as the content of PSMA14 grows. PCL-rich blends exhibited ring-banded spherulites, with a ring periodicity that increased with crystallization temperature and with PSMA14 content. Preliminary results of the phase separation process are given from samples that were thermally treated under different conditions.