Magnetic field screening and mirroring in graphene

The orbital magnetism in spatially varying magnetic fields is studied in monolayer graphene within the effective mass approximation. We find that, unlike the conventional two-dimensional electron system, graphene with small Fermi wave number k_F works as a magnetic shield where the field produced by a magnetic object placed above graphene is always screened by a constant factor on the other side of graphene. The object is repelled by a diamagnetic force from the graphene, as if there exists its mirror image with a reduced amplitude on the other side of graphene. The magnitude of the force is much greater than that of conventional two-dimensional system. The effect disappears with the increase of k_F.Comment: 5 pages, 3 figure

Wide-Area Mapping of 155 Micron Continuum Emission from the Orion Molecular Cloud Complex

We present the results of a wide-area mapping of the far-infrared continuum emission toward the Orion complex by using a Japanese balloon-borne telescope. The 155-um continuum emission was detected over a region of 1.5 deg^2 around the KL nebula with 3' resolution similar to that of the IRAS 100-um map. Assuming a single-temperature model of the thermal equilibrium dust, maps of the temperature and the optical depth were derived from the 155 um intensity and the IRAS 100 um intensity. The derived dust temperature is 5 - 15 K lower and the derived dust optical thickness were derived from the 155-um intensity and the IRAS 100-um intensity. The derived dust temperature is 5 - 15 K lower and the derived dust optical depth is 5 - 300 times larger than those derived from the IRAS 60 and 100-um intensities due to the significant contribution of the statistically heated very small grains to the IRAS 60-um intensity. The optical-thickness distribution shows a filamentary dust ridge that has a 1.5 degrees extent in the north - south direction and well resembles the Integral-Shaped Filament (ISF) molecular gas distribution. The gas-to-dust ratio derived from the CO molecular gas distribution along the ISF is in the range 30 - 200, which may be interpreted as being an effect of CO depletion due to the photodissociation and/or the freezing on dust grains.Comment: 23 pages, 7 figures, 1 table, to appear in PASJ, Vol. 56, No.

UPGRADED M501G OPERATING EXPERIENCE

ABSTRACT In 2003 the M501G at Mitsubishi's in-house combined cycle power plant facility located at Takasago (T-Point) was upgraded. The upgrade was accomplished by replacing some of the existing hardware in the M501G gas turbine, for further improvements in output and heat rate. The verification testing at this power plant has been continuing with MHI's latest upgraded combustor technology, that has successfully demonstrated NOx levels at 15ppm and 9ppm or lower emission levels in Mitsubishi's G and F gas turbines, respectively. The upgraded M501G has been officially designated as the M501G1 gas turbine. This paper describes the upgraded hardware and the operating experience at the T-Point power plant

Herbivore-induced terpenoid emission in Medicago truncatula: concerted action of jasmonate, ethylene and calcium signaling

Plant volatiles emitted by Medicago truncatula in response to feeding larvae of Spodoptera exigua are composed of a complex blend of terpenoids. The cDNAs of three terpene synthases (TPSs), which contribute to the blend of terpenoids, were cloned from M. truncatula. Their functional characterization proved MtTPS1 to be a β-caryophyllene synthase and MtTPS5 to be a multi-product sesquiterpene synthase. MtTPS3 encodes a bifunctional enzyme producing (E)-nerolidol and geranyllinalool (precursors of C11 and C16 homoterpenes) from different prenyl diphosphates serving as substrates. The addition of jasmonic acid (JA) induced expression of the TPS genes, but terpenoid emission was higher from plants treated with JA and the ethylene precursor 1-amino-cyclopropyl-1-carboxylic acid. Compared to infested wild-type M. truncatula plants, lower amounts of various sesquiterpenes and a C11–homoterpene were released from an ethylene-insensitive mutant skl. This difference coincided with lower transcript levels of MtTPS5 and of 1-deoxy-d-xylulose-5-phosphate synthase (MtDXS2) in the damaged skl leaves. Moreover, ethephon, an ethylene-releasing compound, modified the extent and mode of the herbivore-stimulated Ca2+ variations in the cytoplasm that is necessary for both JA and terpene biosynthesis. Thus, ethylene contributes to the herbivory-induced terpenoid biosynthesis at least twice: by modulating both early signaling events such as cytoplasmic Ca2+-influx and the downstream JA-dependent biosynthesis of terpenoids

Uterine selection of human embryos at implantation

Human embryos frequently harbor large-scale complex chromosomal errors that impede normal development. Affected embryos may fail to implant although many first breach the endometrial epithelium and embed in the decidualizing stroma before being rejected via mechanisms that are poorly understood. Here we show that developmentally impaired human embryos elicit an endoplasmic stress response in human decidual cells. A stress response was also evident upon in vivo exposure of mouse uteri to culture medium conditioned by low-quality human embryos. By contrast, signals emanating from developmentally competent embryos activated a focused gene network enriched in metabolic enzymes and implantation factors. We further show that trypsin, a serine protease released by pre-implantation embryos, elicits Ca2+ signaling in endometrial epithelial cells. Competent human embryos triggered short-lived oscillatory Ca2+ fluxes whereas low-quality embryos caused a heightened and prolonged Ca2+ response. Thus, distinct positive and negative mechanisms contribute to active selection of human embryos at implantation

The effect of dexamethasone on defective nephrin transport caused by ER stress: A potential mechanism for the therapeutic action of glucocorticoids in the acquired glomerular diseases

The mechanism by which glucocorticoids govern antiproteinuric effect in nephrotic syndrome remains unknown. Present study examined the protective role of dexamethasone (DEX) in the intracellular trafficking of nephrin under endoplasmic reticulum (ER) stress. Human embryonic kidney-293 cell line expressing a full-length human nephrin was cultured in mediums containing 5.5 or 25 mM glucose with or without DEX. The result revealed that glucose starvation evoked a rapid ER stress leading to formation of underglycosylated nephrin that was remained in the ER as a complex with calreticulin/calnexin. DEX rescued this interfered trafficking through binding to its receptor and stimulating the mitochondrial transcripts and adenosine 5′ triphosphate (ATP) production, leading to synthesis of fully glycosylated nephrin. These results suggest that ER-stress in podocytes may cause alteration of nephrin N-glycosylation, which may be an underlying factor in the pathomechanism of the proteinuria in nephrotic syndrome. DEX may restore this imbalance by stimulating expression of mitochondrial genes, resulted in the production of ATP that is essential factor for proper folding machinery aided by the ER chaperones

Novel role for the innate immune receptor toll-like receptor 4 (TLR4) in the regulation of the wnt signaling pathway and photoreceptor apoptosis

Recent evidence has implicated innate immunity in regulating neuronal survival in the brain during stroke and other neurodegenerations. Photoreceptors are specialized light-detecting neurons in the retina that are essential for vision. In this study, we investigated the role of the innate immunity receptor TLR4 in photoreceptors. TLR4 activation by lipopolysaccharide (LPS) significantly reduced the survival of cultured mouse photoreceptors exposed to oxidative stress. With respect to mechanism, TLR4 suppressed Wnt signaling, decreased phosphorylation and activation of the Wnt receptor LRP6, and blocked the protective effect of the Wnt3a ligand. Paradoxically, TLR4 activation prior to oxidative injury protected photoreceptors, in a phenomenon known as preconditioning. Expression of TNFα and its receptors TNFR1 and TNFR2 decreased during preconditioning, and preconditioning was mimicked by TNFα antagonists, but was independent of Wnt signaling. Therefore, TLR4 is a novel regulator of photoreceptor survival that acts through the Wnt and TNFα pathways. © 2012 Yi et al

Genetics of Mechanosensation in the Heart

Mechanosensation (the ultimate conversion of a mechanical stimulus into a biochemical signal) as well as mechanotransduction (transmission of mechanically induced signals) belong to the most fundamental processes in biology. These effects, because of their dynamic nature, are particularly important for the cardiovascular system. Therefore, it is not surprising that defects in cardiac mechanosensation, are associated with various types of cardiomyopathy and heart failure. However, our current knowledge regarding the genetic basis of impaired mechanosensation in the cardiovascular system is beginning to shed light on this subject and is at the centre of this brief review