To seek the origin of positive/negative thermal expansion distinction, the mode Gruneisen parameters and the phonon spectra are investigated. They indicate that different low-frequency phonon vibration modes correspond to the change of thermal expansions. Below 5 THz, the significant weighted negative values of mode Gruneisen parameters, caused by the weakening of mixing-mode constituted with two transverse acoustic (TA) modes and a small overlapped Selleck Dibutyryl-cAMP part of optical modes, directly lead to the negative thermal expansion at low temperatures. (C) 2011 American
Institute of Physics. [doi:10.1063/1.3627237]“
“Penetrating spinal injuries from foreign bodies are an exceedingly rare pathological entity. In this report we present an unusual clinical report of an indriven shard of glass in the cervical spine that
remained without symptoms for many years and became symptomatic possibly because of narrowing of the diameter of the vertebral canal.”
“The effect of maleic anhydride-grafted hard paraffin wax (MA-g-wax) and oxidized hard paraffin wax (OxWax), as possible compatibilizers, Ruboxistaurin cost on the morphology, thermal and mechanical properties of LDPE/sisal fiber composites were examined. The differential scanning calorimetry (DSC) results show that sisal alone did not change the crystallization behavior of LDPE, while the two waxes influenced the crystallization behavior of LDPE in different ways, whether mixed with LDPE
alone or in the presence of sisal. The thermal properties seem to be influenced by the fact that the waxes preferably crystallize around the short sisal fibers, and by the fact that the two waxes have different compatibilities with LDPE. The TGA results show an increase in the thermal stability of the blends in the presence of the two waxes, with LDPE/OxWax showing a more significant improvement. The presence of wax, however, reduced the thermal stability of the LDPE/sisal/wax composites. The presence of OxWax and MA-g-wax similarly influenced the tensile properties of the composites. Both waxes similarly improved the modulus of the compatibilized C59 in vitro composites, but in both cases the tensile strengths were worse, probably because of a fairly weak interaction between LDPE and the respective waxes. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 123: 3627-3634, 2012″
“Brain derived neurotrophic factor (BDNF) regulates several CNS physiological and pathological processes. To investigate in multiple sclerosis (MS) patients, the relationship between the Val66Met polymorphism of BDNF and clinical markers of disease activity and MRI markers of focal and diffuse brain pathologies. 45 MS patients and 34 healthy controls (HCs) were genotyped and subjected to clinical-MRI examination. Global white matter fraction (gWM-f), gray matter-f (GM-f), cerebrospinal fluid-f (CSF-f), and abnormal WM-f were measured.
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