Deformation Effects During Forging of Large Ingots

Metallurgist - Technology is provide for the effect of deformation on ingot microstructure during forging in hydraulic presses. Five deformation effects are realized during forging with traditional...     

Microlens-Enhanced Substrate Patterning and MBE Growth of GaP Nanowires

Semiconductors - In this paper we demonstrate the results on selective area growth of GaP nanowires via self-catalyzed growth method using molecular beam epitaxy (MBE) technique on patterned...     

Inherited disorders in sexual development

Ascariasis is a well-known cause of acute cholangitis and cholecystitis; however, very rarely do worms penetrate and colonize the liver parenchyma. Here we present the unique radiological demonstration (US, CT and ERCP) of hepatobiliary ascariasis in which worm was first alive in the parenchyma of the liver and subsequently died and formed liver abscess.     

Lymphotoxin alpha/beta and tumor necrosis factor are required for stromal cell expression of homing chemokines in B and T cell areas of the spleen

Mice deficient in the cytokines tumor necrosis factor (TNF) or lymphotoxin (LT) alpha/beta lack polarized B cell follicles in the spleen. Deficiency in CXC chemokine receptor 5 (CXCR5), a receptor for B lymphocyte chemoattractant (BLC), also causes loss of splenic follicles. Here we report that BLC expression by follicular stromal cells is defective in TNF-, TNF receptor 1 (TNFR1)-, LTalpha- and LTbeta-deficient mice. Treatment of adult mice with antagonists of LTalpha1beta2 also leads to decreased BLC expression. These findings indicate that LTalpha1beta2 and TNF have a role upstream of BLC/CXCR5 in the process of follicle formation. In addition to disrupted follicles, LT-deficient animals have disorganized T zones. Expression of the T cell attractant, secondary lymphoid tissue chemokine (SLC), by T zone stromal cells is found to be markedly depressed in LTalpha-, and LTbeta-deficient mice. Expression of the SLC-related chemokine, Epstein Barr virus-induced molecule 1 ligand chemokine (ELC), is also reduced. Exploring the basis for the reduced SLC expression led to identification of further disruptions in T zone stromal cells. Together these findings indicate that LTalpha1beta2 and TNF are required for the development and function of B and T zone stromal cells that make chemokines necessary for lymphocyte compartmentalization in the spleen.     

GS32, a novel Golgi SNARE of 32 kDa, interacts preferentially with syntaxin 6

Syntaxin 1, synaptobrevins or vesicle-associated membrane proteins, and the synaptosome-associated protein of 25 kDa (SNAP-25) are key molecules involved in the docking and fusion of synaptic vesicles with the presynaptic membrane. We report here the molecular, cell biological, and biochemical characterization of a 32-kDa protein homologous to both SNAP-25 (20% amino acid sequence identity) and the recently identified SNAP-23 (19% amino acid sequence identity). Northern blot analysis shows that the mRNA for this protein is widely expressed. Polyclonal antibodies against this protein detect a 32-kDa protein present in both cytosol and membrane fractions. The membrane-bound form of this protein is revealed to be primarily localized to the Golgi apparatus by indirect immunofluorescence microscopy, a finding that is further established by electron microscopy immunogold labeling showing that this protein is present in tubular-vesicular structures of the Golgi apparatus. Biochemical characterizations establish that this protein behaves like a SNAP receptor and is thus named Golgi SNARE of 32 kDa (GS32). GS32 in the Golgi extract is preferentially retained by the immobilized GST-syntaxin 6 fusion protein. The coimmunoprecipitation of syntaxin 6 but not syntaxin 5 or GS28 from the Golgi extract by antibodies against GS32 further sustains the preferential interaction of GS32 with Golgi syntaxin 6.     

Identification of 130 kDa cell surface LDL-binding protein from smooth muscle cells as a partially processed T-cadherin precursor

Atypical cell surface lipoprotein-binding proteins of 105 kDa and 130 kDa are present in membranes of vascular smooth muscle cells. We recently identified the 105 kDa protein from human aortic media as T-cadherin, an unusual glycosylphosphatidylinositol (GPI)-anchored member of the cadherin family of cell adhesion proteins. The goal of the present study was to determine the identity of 130 kDa lipoprotein-binding protein of smooth muscle cells. We applied different approaches that included protein sequencing of purified protein from human aortic media, the use of human T-cadherin peptide-specific antisera, and enzymatic treatment of cultured cells with trypsin and GPI-specific phospholipase C. Our results indicate that the 130 kDa protein is a partially processed form of T-cadherin which is attached to the membrane surface of smooth muscle cells via a GPI anchor and contains uncleaved N-terminal propeptide sequence. Our data disclose that, in contrast to classical cadherins, T-cadherin is expressed on the cell surface in both its precursor (130 kDa) and mature (105 kDa) forms.     

Experience in eddy-current testing of mounting holes in aircraft components

Opportunities offered by the static and dynamic eddy-current techniques for testing mounting holes in aircraft components fabricated from nonmagnetic materials and features of these techniques are considered. Examples of applications of eddy-current techniques demonstrating considerable advantages of the dynamic technique in detection of cracks around holes are given.     

Dynamics of the N-terminal alpha-helix unfolding in the photoreversion reaction of phytochrome A

Time-resolved circular dichroism spectroscopy in the far-UV spectral region was used to examine the intermediates of the phytochrome photoreversion reaction (Pfr --> Pr). Three intermediates, lumi-F (tau = 320 ns), meta-Fa (tau = 265 micros) and meta-Fb (tau = 5.5 ms), have been identified in a simple sequential kinetic photoreversion mechanism by absorption spectroscopy [Linschitz, H., Kasche, V., Butler, W. L., & Siegelman, H. W. (1966) J. Biol. Chem. 241, 3395-3403; Pratt, L. H., & Butler, W. L. (1968) Photochem. Photobiol. 8, 477-485; Burke, M., Pratt, D. C., & Moscowitz, A. (1972) Biochemistry 11, 4025-4031; Spruit, C. J. P., Kendrick, R. E., & Cooke, R. J. (1975) Planta (Berlin) 127, 121-132; Eilfeld, P., & Rüdiger, W. (1985) Z. Naturforsch. 40c, 109-114; Chen, E., Lapko, V. N., Lewis, J. W., Song, P.-S., & Kliger, D. S. (1996) Biochemistry 35, 843-850]. In order to correlate the unfolding of the N-terminal alpha-helical segment with one or more of the intermediate species, time-resolved methods were coupled with the structurally sensitive probe of CD in the far-UV spectral region. Analysis of the TRCD data associates the decrease in alpha-helical content that occurs upon formation of Pr with decay of the meta-Fa intermediate. This unfolding process occurs with a time constant of 310 +/- 125 micros, which is consistent with the 265-micros lifetime for meta-Fa.