236 research outputs found

    A simple characterization of special matchings in lower Bruhat intervals

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    We give a simple characterization of special matchings in lower Bruhat intervals (that is, intervals starting from the identity element) of a Coxeter group. As a byproduct, we obtain some results on the action of special matchings.Comment: accepted for publication on Discrete Mathematic

    Modeling the effect of subsurface interface defects on contact stiffness for ultrasonic atomic force microscopy

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    Cataloged from PDF version of article.We present a model predicting the effects of mechanical defects at layer interfaces on the contact stiffness measured by ultrasonicatomic force microscopy(AFM). Defects at subsurface interfaces result in changes at the local contact stiffness between the AFM tip and the sample. Surface impedance method is employed to model the imperfections and an iterative algorithm is used to calculate the AFM tip-surface contact stiffness. The sensitivity of AFM to voids or delaminations and disbonds is investigated for film-substrate combinations commonly used in microelectronic structures, and optimum defect depth for maximum sensitivity is defined. The effect of contact force and the tip properties on the defect sensitivity are considered. The results indicate that the ultrasonicAFM should be suitable for subsurface detection and its defect sensitivity can be enhanced by adjusting the applied force as well as by judicious choice of the AFM tip material and geometry. © 2004 American Institute of Physic

    Original Article

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    Phosphodiesterase specific for the hydrolysis of diphenylphosphate, one of aromatic phosphodiesters, was obtained from hog kidney by following procedure. To hog kidney homogenized in a Waring blendor with 3 volumes of distilled water was added solid sodium chloride to a final concentration of 1% and after adjusting of pH to 5 with ca. 5 N hydrochloric acid, it was shaken for 10 minutes with an equal volume of n-butanol, allowed to stand for one hour, and centrifuged. The aqueous extract present beneath the floating gel layer of protein and butanol mixture, was siphoned out and fractionated with ammonium sulfate. The precipitate obtained between 45 and 70 % saturation was dissolved in a small volume of distilled water, dialyzed for 48 hours against running tap water, and then, to inactivate the monoesterase, heated in water bath of 100° for 5 minutes, whereby the solution became faintly turbid. The enzyme solution, thus prepared, hydrolyzed diphenylphosphate, liberating phenol but no inorganic phosphate, while it was inactive to monophenylphosphate. Diphenylphosphate of a final concentration of 0.0005M could be hydrolyzed in one hour at the optimum pH 7 to the extent of 40%. At this pH, the enzyme activity was not influenced by addition of Mg^, Ca^, or CN^. Bis-dichloroisopropylphosphate, dibenzylphosphate, diethylphosphate, lysolecithin, RNA, and DNA were resistant to this enzyme. It is conceivable that these diesters are hydrolyzed by other enzymes different from the aromatic phosphodiesterase, presented in this paper

    Different quantities of manganese oxide nanoparticles incorporated feed on the growth and haematological traits of common carp Cyprinus carpio var. communis

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    In recent times, nanoparticles have been used as raw ingredients for biofertilizers, mineral supplements in animal feed, and pharmaceuticals. Manganese plays a vital role in enhancing fish's growth and biological function. The present research work aimed to analyze the various quantities of manganese oxide nanoparticles on common carp growth and its haematological traits. Synthesized manganese oxide (Mn3O4) nanoparticles were illustrated using UV-visible Spectroscopy (UV-Vis), Scanning Electron Microscope (SEM), Energy Dispersive X–Ray Spectroscopy (EDAX), X–Ray Diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FTIR). Six different feeds were prepared by incorporating different quantities of manganese oxide nanoparticles (Feed I (control-0mg), Feed II(3mg/100g), Feed III(6mg/100g), Feed IV(9mg/100g), Feed V(12mg/100g), and Feed VI(15mg/100g)) with common ingredients such as groundnut oil cake, fish meal, tapioca flour, and wheat flour. On the completion of 21 days, feed utilization and haematological characteristics of Common carp were assessed. The UV-Vis showed that manganese oxide nanoparticles exhibit strong adsorption peaks at 220nm. SEM image observed at the wavelength range from 9.22 nm to 9.35 nm. The size of the particles was in the 45-55 nm range. The EDAX spectrum recorded two peaks between 0.40 and 6 kev. The XRD graph shows that the diffraction peaks are indexed as 103, 004, 213, 204, 303, and 215. FT-IR spectrum measured at the wavelength range from 500-4000cm-1. Most of the growth parameters and haematological parameters were higher in feed III, containing 6mg of Manganese oxide nanoparticles. Therefore, results show that manganese oxide incorporated feed enhances the growth and haematological traits in common carp compared to control feed.

    Impact of different quantity of Zinc oxide nanoparticles on growth and hematology of Mrigal Cirrhinus mrigala

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    Zinc is essential for aquatic biota including fishes at a lower concentration, but when it reaches higher concentration it becomes toxic. The objectives of the present work were related to the impact of different quantities of zinc oxide nanoparticles on the growth and hematology of Mrigal Cirrhinus mrigala. The zinc oxide nanoparticles were synthesized by chemical precipitation method and characterized using by UV-VIS, SEM, EDAX, FTIR and XRD. Different quantity of zinc oxide nanoparticles such as 0, 5,10,15,20 and 25mg/100g were prepared by using a fish meal, groundnut oil cake, wheat flour, and tapioca flour. Feed utilization and hematological parameters of Mrigal were estimated after 21 days of feeding. UV-visible adsorption spectra show that the peak absorbance of ZnO nanoparticles was observed 500 nm. SEM shows that nanoparticles formed are clustered because of the adhesive nature of flower-shaped appearance. EDAX shows that the zinc oxide nanoparticles and the peaks are located between 1.0Kev and 8.5Kev. The FTIR spectrum of zinc oxide nanoparticles was analyzed in the range of 400-4000cm-1 and spectral bands were observed. The XRD results were viewed as the crystalline nature and average size of zinc oxide nanoparticles. Survival rate indicated that all Mrigal were healthy during the period of 21 days except in feed II,IV, and V. The feed utilization and growth parameters are higher in feed IV. Hematological parameters such as hemoglobin, RBC, Hematocrit, MCV, MCH, MCHC of Mrigal progressively increased and WBC and platelets decreased with increase in the quantity of Zinc Oxide nanoparticles

    Unique motifs identify PIG-A proteins from glycosyltransferases of the GT4 family

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    <p>Abstract</p> <p>Background</p> <p>The first step of GPI anchor biosynthesis is catalyzed by PIG-A, an enzyme that transfers <it>N</it>-acetylglucosamine from UDP-<it>N</it>-acetylglucosamine to phosphatidylinositol. This protein is present in all eukaryotic organisms ranging from protozoa to higher mammals, as part of a larger complex of five to six 'accessory' proteins whose individual roles in the glycosyltransferase reaction are as yet unclear. The PIG-A gene has been shown to be an essential gene in various eukaryotes. In humans, mutations in the protein have been associated with paroxysomal noctural hemoglobuinuria. The corresponding PIG-A gene has also been recently identified in the genome of many archaeabacteria although genes of the accessory proteins have not been discovered in them. The present study explores the evolution of PIG-A and the phylogenetic relationship between this protein and other glycosyltransferases.</p> <p>Results</p> <p>In this paper we show that out of the twelve conserved motifs identified by us eleven are exclusively present in PIG-A and, therefore, can be used as markers to identify PIG-A from newly sequenced genomes. Three of these motifs are absent in the primitive eukaryote, <it>G. lamblia</it>. Sequence analyses show that seven of these conserved motifs are present in prokaryote and archaeal counterparts in rudimentary forms and can be used to differentiate PIG-A proteins from glycosyltransferases. Using partial least square regression analysis and data involving presence or absence of motifs in a range of PIG-A and glycosyltransferases we show that (i) PIG-A may have evolved from prokaryotic glycosyltransferases and lipopolysaccharide synthases, members of the GT4 family of glycosyltransferases and (ii) it is possible to uniquely classify PIG-A proteins versus glycosyltransferases.</p> <p>Conclusion</p> <p>Besides identifying unique motifs and showing that PIG-A protein from <it>G. lamblia </it>and some putative PIG-A proteins from archaebacteria are evolutionarily closer to glycosyltransferases, these studies provide a new method for identification and classification of PIG-A proteins.</p

    Elucidating the mechanism of DNA-dependent ATP hydrolysis mediated by DNA-dependent ATPase A, a member of the SWI2/SNF2 protein family

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    The active DNA-dependent ATPase A domain (ADAAD), a member of the SWI2/SNF2 family, has been shown to bind DNA in a structure-specific manner, recognizing DNA molecules possessing double-stranded to single-stranded transition regions leading to ATP hydrolysis. Extending these studies we have delineated the structural requirements of the DNA effector for ADAAD and have shown that the single-stranded and double-stranded regions both contribute to binding affinity while the double-stranded region additionally plays a role in determining the rate of ATP hydrolysis. We have also investigated the mechanism of interaction of DNA and ATP with ADAAD and shown that each can interact independently with ADAAD in the absence of the other. Furthermore, the protein can bind to dsDNA as well as ssDNA molecules. However, the conformation change induced by the ssDNA is different from the conformational change induced by stem-loop DNA (slDNA), thereby providing an explanation for the observed ATP hydrolysis only in the presence of the double-stranded:single-stranded transition (i.e. slDNA)

    Microcalcification Crystallography as a Potential Marker of DCIS Recurrence

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    Head and neck squamous cell carcinomas (HNSCCs) have high mortality and significant treatment-related morbidity. It is vital to discover effective, minimally invasive therapies that improve survival and quality of life. Bitter taste receptors (T2Rs) are expressed in HNSCCs, and T2R activation can induce apoptosis. Lidocaine is a local anesthetic that also activates bitter taste receptor 14 (T2R14). Lidocaine has some anti-cancer effects, but the mechanisms are unclear. Here, we find that lidocaine causes intracellular C
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