Protein kinase Cι is required for Ras transformation and colon carcinogenesis in vivo

Protein kinase C ι (PKCι) has been implicated in Ras signaling, however, a role for PKCι in oncogenic Ras-mediated transformation has not been established. Here, we show that PKCι is a critical downstream effector of oncogenic Ras in the colonic epithelium. Transgenic mice expressing constitutively active PKCι in the colon are highly susceptible to carcinogen-induced colon carcinogenesis, whereas mice expressing kinase-deficient PKCι (kdPKCι) are resistant to both carcinogen- and oncogenic Ras-mediated carcinogenesis. Expression of kdPKCι in Ras-transformed rat intestinal epithelial cells blocks oncogenic Ras-mediated activation of Rac1, cellular invasion, and anchorage-independent growth. Constitutively active Rac1 (RacV12) restores invasiveness and anchorage-independent growth in Ras-transformed rat intestinal epithelial cells expressing kdPKCι. Our data demonstrate that PKCι is required for oncogenic Ras- and carcinogen-mediated colon carcinogenesis in vivo and define a procarcinogenic signaling axis consisting of Ras, PKCι, and Rac1

Quantum critical point in SmO1−xFxFeAs and oxygen vacancy induced by high fluorine dopant

The local lattice and electronic structure of the high-T(c) superconductor SmO(1-x)F(x)FeAs as a function of F-doping have been investigated by Sm L(3)-edge X-ray absorption near-edge structure and multiple-scattering calculations. Experiments performed at the L(3)-edge show that the white line (WL) is very sensitive to F-doping. In the under-doped region (x ≤ 0.12) the WL intensity increases with doping and then it suddenly starts decreasing at x = 0.15. Meanwhile, the trend of the WL linewidth versus F-doping levels is just contrary to that of the intensity. The phenomenon is almost coincident with the quantum critical point occurring in SmO(1-x)F(x)FeAs at x ≃ 0.14. In the under-doped region the increase of the intensity is related to the localization of Sm-5d states, while theoretical calculations show that both the decreasing intensity and the consequent broadening of linewidth at high F-doping are associated with the content and distribution of oxygen vacancies

Charge redistribution and local lattice structure of (F, Zn)-codoped LaFeAsO superconductor

To understand the abnormal behavior of the superconducting transition temperature (T-c) because of the presence of a non-magnetic Zn impurity in the (F, Zn)-codoped LaFeAsO system (Li et al 2010 New J. Phys. 12 083008), we investigated its unique electronic and local structures via x-ray absorption spectroscopy and first-principles calculations. The data obtained showed that the presence of a Zn impurity induces an electron transfer from As to Fe atoms in both the F-underdoped and -overdoped regions. Moreover, due to the lattice mismatch, the local lattice structure is finely modulated by both F and Zn impurities. Actually, in the F-underdoped region doping by Zn is associated with regular FeAs4 tetrahedra, while distorted FeAs4 tetrahedra occur in the F-overdoped region where superconductivity is significantly suppressed

Correlation between local vibrations and metal mass in AlB2-type transition-metal diborides

Lattice vibrations have been investigated in TiB2, ZrB2 and HfB2 by temperature-dependent extended X-ray absorption fine structure (EXAFS) experiments. Data clearly show that the EXAFS oscillations are characterized by an anomalous behavior of the Debye-Waller factor of the transition-metal-boron pair, which is suggested to be associated with a superposition of an optical mode corresponding to phonon vibrations induced by the B sublattice and an acoustic mode corresponding to the transition-metal (TM) sublattice. Data can be interpreted as a decoupling of the metal and boron vibrations observed in these transition-metal diborides (TMB2), a mechanism that may be responsible for the significant reduction of the superconducting transition temperature observed in these systems with respect to the parent MgB2 compound. The vibrational behavior of TM-TM bonds has also been investigated to study the occurrence of anisotropy and anomalies in the lattice vibrational behavior of TM-TM bonds

A Dominant X-Linked QTL Regulating Pubertal Timing in Mice Found by Whole Genome Scanning and Modified Interval-Specific Congenic Strain Analysis

BACKGROUND: Pubertal timing in mammals is triggered by reactivation of the hypothalamic-pituitary-gonadal (HPG) axis and modulated by both genetic and environmental factors. Strain-dependent differences in vaginal opening among inbred mouse strains suggest that genetic background contribute significantly to the puberty timing, although the exact mechanism remains unknown. METHODOLOGY/PRINCIPAL FINDINGS: We performed a genome-wide scanning for linkage in reciprocal crosses between two strains, C3H/HeJ (C3H) and C57BL6/J (B6), which differed significantly in the pubertal timing. Vaginal opening (VO) was used to characterize pubertal timing in female mice, and the age at VO of all female mice (two parental strains, F1 and F2 progeny) was recorded. A genome-wide search was performed in 260 phenotypically extreme F2 mice out of 464 female progeny of the F1 intercrosses to identify quantitative trait loci (QTLs) controlling this trait. A QTL significantly associated was mapped to the DXMit166 marker (15.5 cM, LOD = 3.86, p<0.01) in the reciprocal cross population (C3HB6F2). This QTL contributed 2.1 days to the timing of VO, which accounted for 32.31% of the difference between the original strains. Further study showed that the QTL was B6-dominant and explained 10.5% of variation to this trait with a power of 99.4% at an alpha level of 0.05.The location of the significant ChrX QTL found by genome scanning was then fine-mapped to a region of approximately 2.5 cM between marker DXMit68 and rs29053133 by generating and phenotyping a panel of 10 modified interval-specific congenic strains (mISCSs). CONCLUSIONS/SIGNIFICANCE: Such findings in our study lay a foundation for positional cloning of genes regulating the timing of puberty, and also reveal the fact that chromosome X (the sex chromosome) does carry gene(s) which take part in the regulative pathway of the pubertal timing in mice

Synthesis and characterization of Zn₁₋ₓMnₓO nanowires

©2008 American Institute of Physics. The electronic version of this article is the complete one and can be found online at: http://link.aip.org/link/?APPLAB/92/162102/1DOI:10.1063/1.2905274Mn doped ZnO nanowires (NWs) were fabricated by a one-step vapor-solid process at 500°C. The doped Mn exists in the wurtzite lattice as substitutional atom without forming secondary phases. X-ray absorption near-edge structure reveals that the doped Mn atoms occupy the Zn sites, and they lead to an expansion in lattice constants. The I-V characteristic of a single Zn₁₋ₓMnₓO NW shows a typical Ohmic contact with gold electrodes. The as-received NWs could be suitable for studying spintronics in one-dimensional diluted magnetic semiconductors

The Real-Time Monitoring System for Metro Shield Tunnels: From Research to Application

International audienceTo the tunnel structure in soft soil foundation, damages are likely caused by large deformation, thus it is reasonable to measure deformation rather than to measure force or stress. Although there are many ways to obtain deformation information, measuring inclination of segments is one of the most effective ways, and it is convenient to derive the deformation from the inclination data. The method to obtain the variation of tunnelÕs diameter, the opening length of longitudinal connecting seams, the concrete stress of bolt and certain joint is studied in this paper by making use of the inclination variation of lining segments. This paper outlines a real-time monitoring system based on the internet of things which will be applied to an interval shield tunnel of Shanghai metro line 12 this year