Sporopollenin, a natural copolymer, is robust under high hydrostatic pressure

Lycopodium sporopollenin, a natural copolymer, shows exceptional stability under high hydrostatic pressures (10 GPa) as determined by in situ high pressure synchrotron source FTIR spectroscopy. This stability is evaluated in terms of the component compounds of the sporopollenin: p-coumaric acid, phloretic acid, ferulic acid, and palmitic and sebacic acids, which represent the additional n-acid and ndiacid components. This high stability is attributed to interactions between these components, rather than the exceptional stability of any one molecular component. We propose a biomimetic solution for the creation of polymer materials that can withstand high pressures for a multitude of uses in aeronautics, vascular autografts, ballistics and light-weight protective materials

Vibrational Behavior of the M\u3csub\u3en+1\u3c/sub\u3e\u3cem\u3eAX\u3csub\u3en\u3c/sub\u3e\u3c/em\u3e Phases from First-Order Raman Scattering (\u3cem\u3eM\u3c/em\u3e=Ti,V,Cr, \u3cem\u3eA\u3c/em\u3e=Si, \u3cem\u3eX\u3c/em\u3e=C,N)

We report on the Raman spectra of Ti3SiC2 (312), M2AlC(211) (M=Ti, V, Cr, and Nb) and Ti4AlN3 (413), as representative compounds from the family of Mn+1AXn phases. Intense and narrow first-order Raman peaks are observed, and we present an analysis of the spectra based on symmetry considerations and from results of first-principles calculations of phonon frequencies. The agreement between experimental and calculated mode energies is excellent. The identification of the modes enables application of Raman scattering as a diagnostic tool for the detailed study of the structural and physical properties of this family of compounds and their engineered solid solutions

Brain serotonin synthesis capacity in obsessive-compulsive disorder: effects of cognitive behavioral therapy and sertraline.

Cognitive behavioral therapy (CBT) and selective serotonin reuptake inhibitors (SSRIs) are both effective treatments for some patients with obsessive-compulsive disorder (OCD), yet little is known about the neurochemical changes related to these treatment modalities. Here, we used positron emission tomography and the α-[11C]methyl-L-tryptophan tracer to examine the changes in brain regional serotonin synthesis capacity in OCD patients following treatment with CBT or SSRI treatment. Sixteen medication-free OCD patients were randomly assigned to 12 weeks of either CBT or sertraline treatment. Pre-to-post treatment changes in the α-[11C]methyl-L-tryptophan brain trapping constant, K* (ml/g/min), were assessed as a function of symptom response, and correlations with symptom improvement were examined. Responders/partial responders to treatment did not show significant changes in relative regional tracer uptake; rather, in responders/partial responders, 12 weeks of treatment led to serotonin synthesis capacity increases that were brain-wide. Irrespective of treatment modality, baseline serotonin synthesis capacity in the raphe nuclei correlated positively with clinical improvement. These observations suggest that, for some patients, successful remediation of OCD symptoms might be associated with greater serotonergic tone

Tetralogy of Fallot: Imaging of common and uncommon associations by multidetector CT

AbstractPurposeTo demonstrate the superior role of multidetector computed tomography (MDCT) in delineation of the extracardiac vascular abnormalities including the pulmonary arterial tree, major aortopulmonary collateral arteries (MAPCAs), patent ductus arteriosus (PDA), and also the detection of the common and uncommon findings in Fallot Tetralogy cases for proper pre-surgical evaluation.Material and methodsA retrospective study of all multidetector CT images acquired to evaluate suspected cases of Tetralogy of Fallot sent by their respective referring physicians between April 2009 and August 2010. A total of 23 cases were included in this study. MDCT protocol, image analysis and calculations used in the diagnosis are explained in detail.ResultsDetailed explanation of the MDCT imaging findings in the 23 cases with Tetralogy of Fallot, as well as the common and uncommon associations of the disease, namely pulmonary atresia, MAPCAs, PDAs, atrial septal defects (ASDs), right sided aortic arch, and a few less common associations.ConclusionA customized approach to MDCT imaging improves the diagnostic accuracy and reduces unneeded prolongation of the study and sedation times. A careful preoperative perceptive of the complex cardiovascular anatomy in patients with Tetralogy of Fallot aids in exposing the patient to a directed and prepared surgical approach

Rare case of coronary to pulmonary vein fistula with coronary steal phenomenon

Coronary artery fistulas are abnormal connections between coronary artery territories and cardiac chambers or major vessels, most of them are congenital. Patients with coronary artery fistula can be asymptomatic or present with different symptoms like angina. Cardiac computed tomography (CT) is one of the best modalities for diagnosis. We present an elderly patient that presented with angina symptoms, non invasive stress test was positive for ischemic heart disease, coronary angiogram could not reveal any obstructive lesions, but an abnormal branch of the left descending coronary artery (LAD), cardiac CT showed fistula that connect left anterior descending coronary artery to left superior pulmonary vein. Our case is extremely rare as most of the reported cases were fistulas between LAD and pulmonary artery, but in our case the fistula between LAD and left superior pulmonary vein. In addition, our patients\u27 symptoms resolved with anti-ischemic medical treatment without any surgical intervention

Elastic properties, thermal stability, and thermodynamic parameters of MoAlB

MoAlB is the first and, so far, the only transition-metal boride that forms alumina when heated in air and is thus potentially useful for high-temperature applications. Herein, the thermal stability in argon and vacuum atmospheres and the thermodynamic parameters of bulk polycrystalline MoAlB were investigated experimentally. At temperatures above 1708 K, in vacuum and inert atmospheres, this compound incongruently melts into the binary MoB and liquid aluminum metal as confirmed by differential thermal analysis, quenching experiments, x-ray diffraction, and scanning electron microscopy. Making use of that information together with heat-capacity measurements in the 4–1000-K temperature range—successfully modeled as the sum of lattice, electronic, and dilation contributions—the standard enthalpy, entropy, and free energy of formation are computed and reported for the full temperature range. The standard enthalpy of formation of MoAlB at 298 K was found to be −132±3.2 kJ/mol. Lastly, the thermal conductivity values are computed and modeled using a variation of the Slack model in the 300–1600-K temperature range

Nanoporous Carbide Derived Carbon with Tunable Pore Size

During the past decades major efforts in the field of porous materials have been directed toward control of the size, shape and uniformity of the pores. Carbide-derived carbons (CDCs) represent a new class of nanoporous carbons with porosity that can be tuned with sub-Ångström accuracy in the range 0.5-2 nm. CDCs have a more narrow pore size distribution than single-wall carbon nanotubes or activated carbons; their pore size distribution is comparable with that of zeolites. CDCs are produced at temperatures from 200-1200oC as a powder, a coating, a membrane or parts with near-final shapes, with or without mesopores. They can find applications in molecular sieves, gas storage, catalysts, adsorbents, battery electrodes, supercapacitors, water/air filters and medical devices

Global Analysis of Predicted G Protein-Coupled Receptor Genes in the Filamentous Fungus, Neurospora crassa.

G protein-coupled receptors (GPCRs) regulate facets of growth, development, and environmental sensing in eukaryotes, including filamentous fungi. The largest predicted GPCR class in these organisms is the Pth11-related, with members similar to a protein required for disease in the plant pathogen Magnaporthe oryzae. However, the Pth11-related class has not been functionally studied in any filamentous fungal species. Here, we analyze phenotypes in available mutants for 36 GPCR genes, including 20 Pth11-related, in the model filamentous fungus Neurospora crassa. We also investigate patterns of gene expression for all 43 predicted GPCR genes in available datasets. A total of 17 mutants (47%) possessed at least one growth or developmental phenotype. We identified 18 mutants (56%) with chemical sensitivity or nutritional phenotypes (11 uniquely), bringing the total number of mutants with at least one defect to 28 (78%), including 15 mutants (75%) in the Pth11-related class. Gene expression trends for GPCR genes correlated with the phenotypes observed for many mutants and also suggested overlapping functions for several groups of co-transcribed genes. Several members of the Pth11-related class have phenotypes and/or are differentially expressed on cellulose, suggesting a possible role for this gene family in plant cell wall sensing or utilization