Comment on Anomalies in K_<1-x>Rb_xC_8 (2)

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Evidence of ratchet effect in nanowires of a conducting polymer

Ratchet effect, observed in many systems starting from living organism to artificially designed device, is a manifestation of motion in asymmetric potential. Here we report results of a conductivity study of Polypyrrole nanowires, which have been prepared by a simple method to generate a variation of doping concentration along the length. This variation gives rise to an asymmetric potential profile that hinders the symmetry of the hopping process of charges and hence the value of measured resistance of these nanowires become sensitive to the direction of current flow. The asymmetry in resistance was found to increase with decreasing nanowire diameter and increasing temperature. The observed phenomena could be explained with the assumption that the spatial extension of localized state involved in hopping process reduces as the doping concentration reduces along the length of the nanowires.Comment: Revtex, two column, 4 pages, 10 figure

Development of CO2 dry ice heat pump system

A refrigeration temperature below −50.0°C is highly required for the storage of vaccines and fishery catches using natural refrigerants such as CO2 (carbon dioxide). In this study, we have proposed and developed a unique refrigeration system using solid-state CO2 (dry ice) to achieve ultra-low temperatures below −70°C. The initial challenge was the evaporator blockage due to dry ice aggregation, causing system instability. A stainless-steel spiral coil (swirl promoter) was introduced at the evaporator/sublimator inlet to enhance heat transfer and alleviate the blockage problem. The system, which operates effectively at the triple point of approximately −60°C and 0.5 MPa, is further advanced to its limits by using a cyclone separator/evaporator in its latest stage. By integrating a cold recovery heat exchanger in a cylindrical vessel, the system can maintain ultra-low temperatures of approximately −70°C inside the recovery section, achieving a coefficient of performance of this system (COPsystem) of 1.2. Keywords: Natural Refrigerant, CarbonDdioxide, CO2 Refrigeration System, Dry Ice, Ultra-low TemperatureDevelopment of CO2 dry ice heat pump systemacceptedVersio

Specific and flexible roles of heparan sulfate modifications in Drosophila FGF signaling

Specific sulfation sequence of heparan sulfate (HS) contributes to the selective interaction between HS and various proteins in vitro. To clarify the in vivo importance of HS fine structures, we characterized the functions of the Drosophila HS 2-O and 6-O sulfotransferase (Hs2st and Hs6st) genes in FGF-mediated tracheal formation. We found that mutations in Hs2st or Hs6st had unexpectedly little effect on tracheal morphogenesis. Structural analysis of mutant HS revealed not only a loss of corresponding sulfation, but also a compensatory increase of sulfation at other positions, which maintains the level of HS total charge. The restricted phenotypes of Hsst mutants are ascribed to this compensation because FGF signaling is strongly disrupted by Hs2st; Hs6st double mutation, or by overexpression of 6-O sulfatase, an extracellular enzyme which removes 6-O sulfate groups without increasing 2-O sulfation. These findings suggest that the overall sulfation level is more important than strictly defined HS fine structures for FGF signaling in some developmental contexts

Bilateral Cataract in a Cynomolgus Monkey

Severe bilateral cataract was found in a 7 year-old naïve female cynomolgus monkey (Macaca fascicularis) 3 months before necropsy. During macroscopic examination, severe opacity and thinning of the lens were observed in both eyes. Histopathology revealed that the lens nuclei and majority of cortex lens fibers had disappeared and become excavated, while the lens fibers in the subcapsular area were swollen and distorted. Other observations included atrophy and vacuolation in the lens epithelial cells and proliferation of spindle cells and collagen fiber beneath the anterior capsule of the right eye. Immunohistochemical staining of these spindle cells revealed the presence of vimentin, cytokeratin and α-smooth muscle actin (α-SMA), which were considered to be derived from lens epithelial cells. This is a rare case of spontaneous, bilateral, hypermature cataract in a cynomolgus monkey

Focal Nodular Hyperplasia in the Livers of Cynomolgus Macaques (Macaca Fascicularis)

Two cases of spontaneous focal hepatic hyperplasia were observed in young female cynomolgus macaques (Macaca fascicularis). Grossly, a single raised nodule was observed in the left hepatic lobe. Histopathologically, the nodule compressed surrounding normal tissue; however, the hepatic cords within the nodule continued to those in the nor mal area except in part. Extensive fibrosis and absence of a normal hepatic triad were observed in the nodule. Thin fibrous septa radiating from the dense central stellate scarring and distended vessels were apparent in one animal. Hepatocytes in the nodule lacked cellular atypia, showed frequent PAS-positive eosinophilic inclusions in the cytoplasm and showed higher positive ratios for PCNA. The present cases resembled focal nodular hyperplasia reported in humans and a chimpanzee

Aortoesophageal Fistula after Thoracic Endovascular Aortic Repair for Blunt Thoracic Aortic Injury

Although thoracic endovascular aortic repair (TEVAR) has grown to become the standard of care to treat blunt thoracic aortic injury (BTAI), the long-term effects of TEVAR are still unclear. We here present a 72-year-old man with BTAI due to a traffic accident. He successfully underwent TEVAR and was transferred to another rehabilitation hospital 2 months after the accident. However, 1 month later, he underwent gastroscopy with fever and hematemesis and was diagnosed with aorto-esophageal fistula (AEF). After being re-transferred to Niigata University Medical and Dental Hospital, we tried to convince him to undergo surgical treatment, but he strongly refused. He received palliative care and died due to rupture of the aortic pseudoaneurysm 3 days after the hospital transfer. Fatal complications like AEF may occur after TEVAR, so clinicians need to carefully follow patients who underwent TEVAR