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To explore the factors affecting the shear strength of compacted loess, direct shear tests and compression tests under different moisture contents and compaction were conducted. The results show that the angle of internal friction and the cohesion of the soil depend on the moisture content and compaction. The influence of the moisture content is more significant than that of the compaction. The relationship between the confined compression strain and vertical pressure can be fitted by a hyperbolic curve. The secant modulus has a positive linear relationship with the compaction, and a parabolic correlation with the moisture content. A modified formula for the deformation of loess under changing compaction and moisture content is presented. [ABSTRACT FROM AUTHOR]

Vascular anomalies are among the most common congenital and neonatal dysmorphogenesis, which are separated into hemangiomas and vascular malformations. They can occur in various areas throughout the body, with 60% being located in the head and neck. The true mechanism of pathogenesis of vascular anomalies is still unclear. Various treatment methods have been reported, and there are still controversies over the selection of different treatment modalities. Based on the clinical and basic research and current literature, the Chinese Division of Oral and Maxillofacial Vascular Anomalies formulated a treatment guideline for hemangiomas and vascular malformations of the head and neck, which will be modified and updated periodically based on new medical evidence and research. © 2009 Wiley Periodicals, Inc. Head Neck, 2010 [ABSTRACT FROM AUTHOR]

Aim: N-methyl- D-aspartate receptors (NMDAR) are heteromeric complexes primarily assembled from NR1 and NR2 subunits. In normal conditions, NR2 sub-units assemble into homodimers in the endoplasmic reticulum (ER). These homodimers remain in the ER until they coassemble with NR1 dimers and are trafficked to the cell surface. However, it still remains unclear whether functional homomeric NMDAR exist in physiological or pathological conditions. Methods: We transfected GFP-NR2A alone into HEK293 cells, treated the cells with PKC activator 12-myristate-13 acetate (PMA), and then detected surface NR2A sub-units with a live cell immunostaining method. We also used a series of NR2A mutants with a partial deletion of its C-terminus to identify the regions that are involved in the PMA-mediated surface expression of NR2A subunits. Results: NR2A subunits were expressed on the cell membrane after incubation with PMA (200 nmol/L, 30 min), although no functional NMDA channels were detected after PMA-induced membrane trafficking. Immunostaining with an ER marker also revealed that NR2A subunits were exported from the ER after PMA treatment. Furthermore, the deletion of amino acids between 1149-1347 or 1354-1464 of NR2A inhibited PMA-induced surface expression of NR2A subunits. Conclusion: First, our data suggests that PMA treatment can induce the surface expression of homomeric NR2A subunits. Furthermore, this process is probably mediated by the NR2A C-terminal region between positions 1149 and 1464. [ABSTRACT FROM AUTHOR]

The corpus callosum is the largest commissural system in the mammalian brain, but the mechanisms underlying its development are not well understood. Here we report that neuronal activity is necessary for the normal development and maintenance of callosal projections in the mouse somatosensory cortex. We labeled a subpopulation of layer II/III callosal neurons via in utero electroporation and traced their axons in the contralateral cortex at different postnatal stages. Callosal axons displayed region- and layer-specific projection patterns within the first 2 weeks postnatally. Prenatal suppression of neuronal excitation was achieved via electroporation-induced overexpression of the inward rectifying potassium channel Kir2.1 in layer II/III cortical neurons. This resulted in abnormal callosal projections with many axons extending beyond layers II-III to terminate in layer I. Others failed to terminate at the border between the primary and secondary somatosensory cortices. Blocking synaptic transmission via expression of the tetanus toxin light chain (TeNT-LC) in these axons produced a more pronounced reduction in the projections to the border region, and the eventual disappearance of callosal projections over the entire somatosensory cortex. When Kir2.1 and TeNT-LC were coexpressed, callosal axon targeting exhibited a more severe phenotype that appeared to represent the addition of the effects produced by individual expression of Kir2.1 and TeNT-LC. These results underscore the importance of activity in regulating the developing neural connections and suggest that neuronal and synaptic activities are involved in regulating different aspects of the development of callosal projection. [ABSTRACT FROM AUTHOR]