213 research outputs found
Thermal Properties of Heavy Fermion Compound YbP
Low-temperature specific heat and its field-dependence up to 16 T was
measured in a stoichiometric single crystal of YbP. A sharp peak was observed
at {\it T} = 0.53 K in zero magnetic field. Application of external
field seems to induce a new magnetic phase above 11 T. The field dependence of
the transition temperature in the high-field phase is different from that of
the low field phase. The linear coefficient of the electronic specific heat is
estimated as 120 mJ/mole K from low temperature specfic heat, suggesting
heavy Fermion state in YbP.Comment: to be published in J.Phys.Soc.Jpn on May, 200
Prevalence of equine piroplasmosis in Central Mongolia
Antigen for the indirect fluorescent antibody test (IFAT) was routinely prepared from infected erythrocytes from horses experimentally infected with Babesia equi and Babesia caballi. With the successful
establishment of in vitro cultures of B. equi and B. caballi, it is now possible to employ culture-
derived antigens in this test. In this study, in vitro-propagated B. equi- and B. caballi-infected
erythrocytes were used as antigen in the IFAT. Various modifications to an established protocol had
to be implemented to allow repeatable results. Cultures with 3-4% parasitized erythrocytes were
found to be most suitable. As cross-reactions of control sera on heterologous antigen were observed
at serum dilutions of up to 1/40, a reciprocal titre of 80 was considered to be positive. In positive
samples, specific fluorescence of Babesia parasites and/or erythrocyte membranes was observed.
Fifteen sera from Babesia-free horses from Japan all tested negative in the IFAT. One hundred and
ten field-horse sera from Central Mongolia were investigated in this study. The results indicate that
both B. equi and B. caballi are endemic in horses in Central Mongolia, with 88,2% and 84,5% of
horses being seropositive to B. equi and B. caballi, respectively.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi.
Adobe Acrobat X Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format
Photo-production of neutral kaons on 12C in the threshold region
Kaon photo-production process on C has been studied by measuring
neutral kaons in a photon energy range of 0.81.1 GeV. Neutral kaons were
identified by the invariant mass constructed from two charged pions emitted in
the decay channel. The differential cross sections
as well as the integrated ones in the threshold photon energy region were
obtained. The obtained momentum spectra were compared with a Spectator model
calculation using elementary amplitudes of kaon photo-production given by
recent isobar models. Present result provides, for the first time, the
information on reaction which is expected to play an
important role to construct models for strangeness production by the
electromagnetic interaction. Experimental results show that cross section of
is of the same order to that of and suggest that slightly backward angular distribution
is favored in the process.Comment: 6 pages, 8 figure
Development of Hydrophones for Detecting High-Energy Reactions in Water(III. Accelerator, Synchrotron Radiation, and Instrumentation)
Acoustic detectors were developed using a piezo ceramic compound PZT. A shape of the PZT detector was essential to obtain a high sensitivity. A detector of a spherically shaped shell structure, whose size was 50 mm in diameter and 2 mm thick, was fabricated. Its sensitivity was calibrated to be about 40 mV/Pa at 54 kHz. Using the hydrophone, acoustic signals generated by an electron-induced cascade shower in water were detected. Experimental results were compared with simulation data and confirmed a consistency in between
Molecular Modeling Study for Inhibition Mechanism of Human Chymase and Its Application in Inhibitor Design
Human chymase catalyzes the hydrolysis of peptide bonds. Three chymase inhibitors with very similar chemical structures but highly different inhibitory profiles towards the hydrolase function of chymase were selected with the aim of elucidating the origin of disparities in their biological activities. As a substrate (angiotensin-I) bound crystal structure is not available, molecular docking was performed to dock the substrate into the active site. Molecular dynamics simulations of chymasecomplexes with inhibitors and substrate were performed to calculate the binding orientation of inhibitors and substrate as well as to characterize conformational changes in the active site. The results elucidate details of the 3D chymase structure as well as the importance of K40 in hydrolase function. Binding mode analysis showed that substitution of a heavier Cl atom at the phenyl ring of most active inhibitor produced a great deal of variation in its orientation causing the phosphinate group to interact strongly with residue K40. Dynamics simulations revealed the conformational variation in region of V36-F41upon substrate and inhibitor binding induced a shift in the location of K40 thus changing its interactions with them. Chymase complexes with the most activecompound and substrate were used for development of a hybrid pharmacophore model which was applied in databases screening. Finally, hits which bound well at the active site, exhibited key interactions and favorable electronic properties were identified as possible inhibitors for chymase. This study not only elucidates inhibitorymechanism of chymase inhibitors but also provides key structural insights which will aid in the rational design of novel potent inhibitors of the enzyme. In general, the strategy applied in the current study could be a promising computational approach and may be generally applicable to drug design for other enzymes
Augmentation of Neovascularizaiton in Hindlimb Ischemia by Combined Transplantation of Human Embryonic Stem Cells-Derived Endothelial and Mural Cells
BACKGROUND: We demonstrated that mouse embryonic stem (ES) cells-derived vascular endothelial growth factor receptor-2 (VEGF-R2) positive cells could differentiate into both endothelial cells (EC) and mural cells (MC), and termed them as vascular progenitor cells (VPC). Recently, we have established a method to expand monkey and human ES cells-derived VPC with the proper differentiation stage in a large quantity. Here we investigated the therapeutic potential of human VPC-derived EC and MC for vascular regeneration. METHODS AND RESULTS: After the expansion of human VPC-derived vascular cells, we transplanted these cells to nude mice with hindlimb ischemia. The blood flow recovery and capillary density in ischemic hindlimbs were significantly improved in human VPC-derived EC-transplanted mice, compared to human peripheral and umbilical cord blood-derived endothelial progenitor cells (pEPC and uEPC) transplanted mice. The combined transplantation of human VPC-derived EC and MC synergistically improved blood flow of ischemic hindlimbs remarkably, compared to the single cell transplantations. Transplanted VPC-derived vascular cells were effectively incorporated into host circulating vessels as EC and MC to maintain long-term vascular integrity. CONCLUSIONS: Our findings suggest that the combined transplantation of human ES cells-derived EC and MC can be used as a new promising strategy for therapeutic vascular regeneration in patients with tissue ischemia
Mind the gap: connexins and cellâcell communication in the diabetic kidney
Connexins, assembled as a hexameric connexon, form a transmembrane hemichannel that provides a conduit for paracrine signalling of small molecules and ions to regulate the activity and function of adjacent cells. When hemichannels align and associate with similar channels on opposing cells, they form a continuous aqueous pore or gap junction, allowing the direct transmission of metabolic and electrical signals between coupled cells. Regulation of gap junction synthesis and channel activity is critical for cell function, and a number of diseases can be attributed to changes in the expression/function of these important proteins. Diabetic nephropathy is associated with several complex metabolic and inflammatory responses characterised by defects at the molecular, cellular and tissue level. In both type 1 and type 2 diabetes, glycaemic injury of the kidney is the leading cause of end-stage renal failure, a consequence of multiple aetiologies, including increased deposition of extracellular matrix, glomerular hyperfiltration, albuminuria and tubulointerstitial fibrosis. In diabetic nephropathy, loss of connexin mediated cellâcell communication within the nephron may represent an early sign of disease; however, our current knowledge of the role of connexins in the diabetic kidney is sparse. This review highlights recent evidence demonstrating that maintenance of connexin-mediated cellâcell communication could benefit region-specific renal function in diabetic nephropathy and suggests that these proteins should be viewed as a tantalising novel target for therapeutic intervention
Observation of the Helium 7 Lambda hypernucleus by the (e,e'K+) reaction
An experiment with a newly developed high-resolution kaon spectrometer (HKS)
and a scattered electron spectrometer with a novel configuration was performed
in Hall C at Jefferson Lab (JLab). The ground state of a neutron-rich
hypernucleus, He 7 Lambda, was observed for the first time with the (e,e'K+)
reaction with an energy resolution of ~0.6 MeV. This resolution is the best
reported to date for hypernuclear reaction spectroscopy. The he 7 Lambda
binding energy supplies the last missing information of the A=7, T=1
hypernuclear iso-triplet, providing a new input for the charge symmetry
breaking (CSB) effect of \Lambda N potential.Comment: 5 pages, 4 figures, submitted to PR
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