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Sb
Terms modified by Sb Selected AbstractsStructural and dynamical properties of the Ge(001)/Sb(2×1) surfacePHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 11 2004H. M. Tütüncü Abstract The structural properties of the Ge(001)/Sb(2×1) surface were investigated by using the density functional theory. The calculated structural parameters for this surface are in good agreement with previous experimental and theoretical results. In addition to structural properties, we present the complete phonon spectrum of this surface as calculated from first principles employing density functional theory. We have compared the phonon spectrum of this surface with that of the clean Ge(001)(2×1) surface in detail. We have found that adsorption of Sb results in several characteristic phonon modes. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Natural monoclinic AgPb(Bi2Sb)3S6, an Sb-rich gustaviteACTA CRYSTALLOGRAPHICA SECTION C, Issue 11 2009Richard Pa The crystal structure of the Sb-rich variety of the mineral gustavite, silver lead tris(dibismuth/antimony) hexasulfide, AgPb(Bi2Sb)3S6, consists of blocks of diagonal chains of four octahedra, viz. M1a (Bi), M2a (Sb/Bi), M2b (Bi/Sb) and M1b (Ag), separated by Pb atoms in a trigonal prismatic coordination. Two marginal octahedral sites, M1a and M1b, where the gustavite substitution Ag+ + Bi3+ = 2Pb2+ takes place, are formed by Bi and Ag, respectively. Two central octahedra, M2a and M2b, where the Bi3+ = Sb3+ substitution takes place, are formed by two mixed Bi/Sb sites with different occupancies of Bi and Sb. The alternating occupation of the M1 site by Bi and Ag atoms (which thus creates two distinct sites M1a and M1b) results in the monoclinic space group P21/c. A statistical distribution of Ag/Bi in the M1 position (one mixed Ag/Bi site) was reported for synthetic gustavite, resulting in the orthorhombic space group Cmcm. [source] Adhesive bonding of titanium nitride-plated stainless steel for magnetic attachmentsEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 3 2001Yohsuke Taira The purpose of this study was to evaluate adhesive bonding of resin to titanium nitride ion-plated stainless steel in order for magnetic attachments to survive in the oral environment. Two primers, Cesead II Opaque Primer (CPII) and Metal Primer II (MPII), and one bonding agent, Super-Bond C&B (SB), were used. The surfaces of stainless steel disks were ground and then plated with titanium nitride. After the primer and SB resin were applied, a self-curing resin was bonded to the metal surfaces. Shear bond strengths were determined after 24 h of water storage and after 2,000 thermocycles. Titanium nitride ion-plated stainless steel showed bond strength comparable to the non-plated material. After thermocycling, all specimens of the group no primer/no SB were debonded. The bond strengths of groups CPII/no SB, MPII/no SB and no primer/SB were significantly lower bond strengths than groups CPII/SB and MPII/SB. An appropriate combination of primer and bonding agent should be selected when bonding a magnetic attachment to the denture base. [source] Studies on structural and optical properties of Cu-Sb-O thin filmsPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 9 2010Nadia Chaglabou Abstract We report in this paper the structural and optical properties of Cu-Sb-O thin films systems. Samples were prepared via sequential thermal vacuum deposition of Cu and Sb or Sb and Cu (10 -5 Torr) on glass substrates after what they were heated in vacuum at 200 °C for 1 hour. So, the obtained intermetallic multilayer systems (Cu/Sb)j=1,2,3 and (Sb/Cu)j=1,2,3 were annealed in air atmosphere between 30°C and 400 °C for 3 h for j=1; for 6 h for j=2 and for 9 h for j=3. These films were characterized for their structural, surface morphological, compositional, and optical properties by using X-ray diffraction (XRD) and optical (transmittance and reflectance) measurement techniques. The X-ray diffraction (XRD) patterns revealed the presence of CuO, Sb2O3 and Sb2O4phases. The absorption coefficient of Cu-Sb-O thin films in all cases is in the range104 -105 cm -1. The films after annealing have two direct band gap energies in the ranges 1.48,1.50 eV and 2.20-2.95 eV. The electrical measurements show a conversion from a metallic phase to the semiconductor phase after annealing. The samples exhibit p-type conductivity after annealing in air of the intermetallic multilayer systems (Cu/Sb)j=3 and (Sb/Cu)j=3. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Adhesive bonding of titanium nitride-plated stainless steel for magnetic attachmentsEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 3 2001Yohsuke Taira The purpose of this study was to evaluate adhesive bonding of resin to titanium nitride ion-plated stainless steel in order for magnetic attachments to survive in the oral environment. Two primers, Cesead II Opaque Primer (CPII) and Metal Primer II (MPII), and one bonding agent, Super-Bond C&B (SB), were used. The surfaces of stainless steel disks were ground and then plated with titanium nitride. After the primer and SB resin were applied, a self-curing resin was bonded to the metal surfaces. Shear bond strengths were determined after 24 h of water storage and after 2,000 thermocycles. Titanium nitride ion-plated stainless steel showed bond strength comparable to the non-plated material. After thermocycling, all specimens of the group no primer/no SB were debonded. The bond strengths of groups CPII/no SB, MPII/no SB and no primer/SB were significantly lower bond strengths than groups CPII/SB and MPII/SB. An appropriate combination of primer and bonding agent should be selected when bonding a magnetic attachment to the denture base. [source] 4333: How does scleral buckling affect the anterior segment of the eye?ACTA OPHTHALMOLOGICA, Issue 2010FJ ASCASO Purpose To describe the modifications produced in the anterior segment of the eye after placing an encircling scleral buckling (SB) in terms of corneal morphology, biomechanics and intraocular pressure. Methods A prospective study of 15 eyes with rhegmatogenous retinal detachment who underwent pars plana vitrectomy combined with a scleral buckle (PPV/SB), and 12 eyes with vitreous hemorrhage treated with PPV alone. We measured preoperatively and 1-month after surgery the corneal biomechanical properties using the Ocular Response Analyzer (ORA), including corneal hysteresis (CH), corneal resistance factor (CRF), intraocular pressure (IOPg), and corneal compensated IOP (IOPcc). Moreover, we defined the corneal morphology by 4 parameters provided by the topographer Orbscan IIz: mean corneal power (dioptres), standard deviation, thinnest point (µm), and anterior chamber depth (ACD) (mm). Results Mean CH values were significantly diminished following PPV/SB (p=0.003). We found no significant changes in CRF. IOPg and IOPcc mean values were significantly increased only in the PPV/SB group (p=0.019 and p=0.010, respectively) but not in PPV group (p=0.715 and p=0.273, respectively). In PPV/SB group, IOPcc mean values were significantly higher than IOPg before (p=0.001) and after surgery (p=0.003), but not in the other group. None of the morphological parameters were modified after surgery in any of the two study groups (p>0.05) Conclusion Anterior segment morphology was not modified after placing a SB. Corneal biomechanical properties showed a reduction in CH, probably due to a vascular constriction and reduction of the eye compliance. PPV might be considered a less invasive approach for the repair of noncomplex retinal detachments than PPV/SB. [source] Attenuated endothelin-1 mRNA expression with endothelin-1 receptor blockade during hypoxaemia and reoxygenation in newborn pigletsACTA PAEDIATRICA, Issue 6 2000S Medbø We investigated the cause of decreased plasma endothelin-1 (ET-1) during hypoxaemia and reoxygenation in newborn piglets subjected to simultaneous blocking of the ET-1 receptors. Changes in plasma ET-1 and prepro-ET-1 mRNA expression in the main pulmonary artery and the left lower lobe in the lung were studied in 1-2-d-old piglets. Ten minutes prior to hypoxaemia, the hypoxaemia group (n = 10) was given saline, two groups (both n = 9) were given 1 and 5 mg/kg i.v. SB 217242 (an ET-1 receptor antagonist). Two groups served as normoxic controls, with and without SB 217242 5 mg/kg i.v. Hypoxaemia was induced by ventilating with 8% O2 until base excess was 20mmol/l or mean arterial blood pressure was < 20mmHg. Reoxygenation was performed for 2h with room air. During hypoxaemia, plasma ET-1 decreased in the hypoxaemia group, remained unchanged in the 1-mg group and increased in the 5-mg group. At the end of reoxygenation, plasma ET-1 was above baseline in the 1-mg and 5-mg groups. In the pulmonary artery, the hypoxaemia group showed 2- to 5-fold higher prepro-ET-1 mRNA expression compared to all the other groups (p < 0.05). There were trends for higher prepro-ET-1 mRNA expression in pulmonary tissue in the hypoxaemia group compared to the two receptor-blocking groups (p < 0.07). Conclusions: We conclude that hypoxaemia and reoxygenation increase prepro-ET-1 mRNA expression in the pulmonary artery in newborn piglets. These observations suggest that the half-life of ET-1 is decreased during hypoxaemia and reoxygenation in newborn piglets. [source] Single-beat estimation of the left ventricular end-systolic pressure,volume relationship in patients with heart failureACTA PHYSIOLOGICA, Issue 1 2010E. A. Ten Brinke Abstract Aim:, The end-systolic pressure,volume relationship (ESPVR) constructed from multiple pressure,volume (PV) loops acquired during load intervention is an established method to asses left ventricular (LV) contractility. We tested the accuracy of simplified single-beat (SB) ESPVR estimation in patients with severe heart failure. Methods:, Nineteen heart failure patients (NYHA III-IV) scheduled for surgical ventricular restoration and/or restrictive mitral annuloplasty and 12 patients with normal LV function scheduled for coronary artery bypass grafting were included. PV signals were obtained before and after cardiac surgery by pressure-conductance catheters and gradual pre-load reductions by vena cava occlusion (VCO). The SB method was applied to the first beat of the VCO run. Accuracy was quantified by the root-mean-square-error (RMSE) between ESPVRSB and gold-standard ESPVRVCO. In addition, we compared slopes (EES) and intercepts (end-systolic volume at multiple pressure levels (70,100 mmHg: ESV70,ESV100) of ESPVRSB vs. ESPVRVCO by Bland,Altman analyses. Results:, RMSE was 1.7 ± 1.0 mmHg and was not significantly different between groups and not dependent on end-diastolic volume, indicating equal, high accuracy over a wide volume range. SB-predicted EES had a bias of ,0.39 mmHg mL,1 and limits of agreement (LoA) ,2.0 to +1.2 mmHg mL,1. SB-predicted ESVs at each pressure level showed small bias (range: ,10.8 to +9.4 mL) and narrow LoA. Two-way anova indicated that differences between groups were not dependent on the method. Conclusion:, Our findings, obtained in hearts spanning a wide range of sizes and conditions, support the use of the SB method. This method ultimately facilitates less invasive ESPVR estimation, particularly when coupled with emerging noninvasive techniques to measure LV pressures and volumes. [source] Role of ancillary techniques in diagnosing and subclassifying non-Hodgkin's lymphomas on fine needle aspiration cytologyCYTOPATHOLOGY, Issue 5 2006P. DeyArticle first published online: 8 SEP 200 Non-Hodgkin's lymphomas (NHL) are tumours of the lymphoid cells. During the process of development of lymphoid cells, neoplasia may evolve at any point. Neoplastic cells usually carry the imprint of cell of origin at the stage of origin. Various types of NHL may have similar morphology with wide variation in origin, immunophenotype and other biological features. Different ancillary laboratory techniques may help to overcome the limitations of morphology in this aspect. The commonly used ancillary techniques in lymphomas are immunocytochemistry (IC), flow cytometry, Southern blot (SB) technique, polymerase chain reaction (PCR) and fluorescent in situ hybridization (FISH). In addition, laser scanning cytometry (LSC) and DNA microarray technologies are in the research phase. Various laboratory techniques are used for immunophenotyping, demonstration of monoclonality, identification of chromosomal translocation, assessment of cell kinetics and expression of mRNA in the tumour cells. Flow cytometry helps in rapid immunophenotying of NHL and it has an added advantage over IC in recognizing the co-expression of CD markers. Fine needle aspiration cytology (FNAC) combined with flow immunophenotyping may help us to diagnose and subclassify certain NHLs, such as follicular lymphoma and mantle cell lymphoma, which were previously recognized as pure morphological entities. Loss of morphology is one of the important limitations of flow cytometry. LSC can overcome this limitation by studying morphology along with the immunophenotyping pattern of individual cells. Chromosomal changes in NHL can be identified by SB, PCR and FISH. Molecular diagnosis of NHL helps in diagnosis, subclassification, prognostic assessment and even in planning of therapy. DNA microarray is a relatively newer and promising technology. It gives information about the expression of several thousands of genes in a tumour in a single experiment. In the near future, FNAC combined with ancillary techniques may play a major role in diagnosis, subclassification and management of lymphomas. [source] Mathematical development in spina bifidaDEVELOPMENTAL DISABILITIES RESEARCH REVIEW, Issue 1 2009Lianne H. English Abstract Spina bifida (SB) is a neural tube defect diagnosed before or at birth that is associated with a high incidence of math disability often without co-occurring difficulties in reading. SB provides an interesting population within which to examine the development of mathematical abilities and disability across the lifespan and in relation to the deficits in visual-spatial processing that are also associated with the disorder. An overview of math and its cognitive correlates in preschoolers, school-age children and adults with SB is presented including the findings from a longitudinal study linking early executive functions in infancy to the development of later preschool and school age math skills. These findings are discussed in relation to socio-historical perspectives on math education and implications for intervention and directions for further research are presented. © 2009 Wiley-Liss, Inc. Dev Disabil Res Rev 2009;15:28,34. [source] Serotonin decreases generation of dopaminergic neurons from mesencephalic precursors via serotonin type 7 and type 4 receptorsDEVELOPMENTAL NEUROBIOLOGY, Issue 1 2007J. Parga Abstract Inductive signals mediating the differentiation of neural precursors into serotonergic (5-HT) or dopaminergic neurons have not been clarified. We have recently shown that in cell aggregates obtained from rat mesencephalic precursors, reduction of serotonin levels induces a marked increase in generation of dopaminergic neurons. In the present study we treated rat neurospheres with antagonists of the main subtypes of 5-HT receptors, 5-HT transport inhibitors, or 5-HT receptor agonists, and studied the effects on generation of dopaminergic neurons. Cultures treated with Methiothepin (5-HT1,2,5,6,7 receptor antagonist), the 5-HT4 receptor antagonist GR113808;67:00,.or the 5-HT7 receptor antagonist SB 269970 showed a significant increase in generation of dopaminergic cells. Treatment with the 5-HT1B/1D antagonist GR 127935, the 5-HT2 antagonist Ritanserin, the 5-HT transporter inhibitor Fluoxetine, the dopamine and norepinephrine transport inhibitor GBR 12935, or with both inhibitors together, or 5-HT4 or 5-HT7 receptor agonists induced significant decreases in generation of dopaminergic cells. Cultures treated with WAY100635 (5-HT1A receptor antagonist), the 5-HT3 receptor antagonist Ondasetron, or the 5-HT6 receptor antagonist SB 258585 did not show any significant changes. Therefore, 5-HT4 and 5-HT7 receptors are involved in the observed serotonin-induced decrease in generation of dopaminergic neurons from proliferating neurospheres of mesencephalic precursors. 5-HT4 and 5-HT7 receptors were found in astrocytes and serotonergic cells using double immunolabeling and laser confocal microscopy, and the glial receptors appeared to play a major role. © 2006 Wiley Periodicals, Inc. J Neurobiol 67: 10,22, 2007 [source] Habitat use of age 0 Alabama shad in the Pascagoula River drainage, USAECOLOGY OF FRESHWATER FISH, Issue 1 2010P. F. Mickle Mickle PF, Schaefer JF, Adams SB, Kreiser BR. Habitat use of age 0 Alabama shad in the Pascagoula River drainage, USA. Ecology of Freshwater Fish 2010: 19: 107,115. © 2009 John Wiley & Sons A/S Abstract,, Alabama shad (Alosa alabamae) is an anadromous species that spawns in Gulf of Mexico drainages and is a NOAA Fisheries Species of Concern. Habitat degradation and barriers to migration are considered contributing factors to range contraction that has left just the Pascagoula River drainage population in Mississippi. We studied juvenile life history and autecology in three rivers within the drainage. We collected fish, habitat and physicochemical data in three habitat types (sandbar, open channel and bank) from June to October 2004,2006. Sandbar habitat was favoured by smaller individuals early in the year. Catch per unit effort (CPUE) decreased through the summer as larger fish began occupying bank and open channel habitat. The most parsimonious model of abundance included year and river variables, while patterns of presence and absence were best explained by river, habitat type and physiochemical variables. While all three rivers in the drainage contained Alabama shad, fish were less abundant and had lower condition values in the Chickasawhay River. Earlier work suggested the Alabama shad may gradually move downstream towards the Gulf of Mexico in their first year. However, we found no evidence of this and captured large fish high in the drainage late in the year. [source] c-Src kinase activation regulates preprotachykinin gene expression and substance P secretion in rat sensory gangliaEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 7 2003Orisa J. Igwe Abstract Increased synthesis of substance P (SP) in the dorsal root ganglia (DRG) and enhanced axonal transport to and secretion from the primary afferent sensory neurons might enhance pain signalling in the spinal dorsal horn by modifying pronociceptive pathways. IL-1, increases SP synthesis by enhancing the expression of preprotachykinin (PPT) mRNA encoding for SP and other tachykinins in the DRG. Stimulation of IL-1 receptor by IL-1, may induce the phosphorylation of tyrosine residues in many effector proteins through the activation of p60c-src kinase. The hypothesis that the synthesis of SP in and secretion from the primary sensory ganglia are regulated by the activation of p60c-src kinase induced by IL-1, was tested. Pretreatment of DRG neurons in culture with herbimycin A, genistein or PP2, three structurally different nonreceptor tyrosine kinase inhibitors that act by different mechanisms, decreased the kinase activity of p60c-src induced by the activation of IL-1 receptor. PP3, a negative control for the Src family of tyrosine kinase inhibitor PP2 had no effect. Herbimycin A and genistein also decreased IL-1,-induced expression of PPT mRNA-encoding transcripts and the levels of SP-li synthesized in the cells and secreted into the culture medium in a concentration-dependent manner. SB 203580 [a p38 mitogen-activated protein kinase (p38 MAPK) inhibitor] and PD 98059 (a p44/42 MAPK kinase inhibitor) were ineffective in modulating IL-1,-induced SP synthesis and secretion, and p60c-src kinase activity in DRG neurons. Whereas, IL-1 receptor antagonist and cycloheximide inhibited IL-1,-evoked secretion of SP-like immunoreactivity (SP-li), actinomycin D decreased it significantly but did not entirely abolish it. These findings show that phosphorylation of specific protein tyrosine residue(s) following IL-1 receptor activation might play a key role in IL-1, signalling to modulate PPT gene expression and SP secretion in sensory neurons. In view of the role of SP as an immunomodulator, these studies provide a new insight into neural-immune intercommunication in pain regulation in the sensory ganglia through the IL-1,-induced p60c-src activation. [source] Effects of an occlusal splint compared with cognitive-behavioral treatment on sleep bruxism activityEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 1 2007Michelle A. Ommerborn The impact of an occlusal splint (OS) compared with cognitive-behavioral treatment (CBT) on the management of sleep bruxism (SB) has been poorly investigated. The aim of this study was to evaluate the efficacy of an OS with CBT in SB patients. Following a randomized assignment, the OS group consisted of 29, and the CBT group of 28, SB patients. The CBT comprised problem-solving, progressive muscle relaxation, nocturnal biofeedback, and training of recreation and enjoyment. The treatment took place over a period of 12 wk, and the OS group received an OS over the same time period. Both groups were examined pretreatment, post-treatment, and at 6 months of follow-up for SB activity, self-assessment of SB activity and associated symptoms, psychological impairment, and individual stress-coping strategies. The analyses demonstrated a significant reduction in SB activity, self-assessment of SB activity, and psychological impairment, as well as an increase of positive stress-coping strategies in both groups. However, the effects were small and no group-specific differences were seen in any dependent variable. This is an initial attempt to compare CBT and OS in SB patients, and the data collected substantiate the need for further controlled evaluations, using a three-group randomized design with repeated measures to verify treatment effects. [source] Adhesive bonding of titanium,aluminum,niobium alloy with nine surface preparations and three self-curing resinsEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 2 2003Hiroaki Yanagida The purpose of the current study was to evaluate the adhesive performance of metal conditioners when used for bonding between auto-polymerizing methacrylic resins and a titanium alloy. Disk specimens were cast from a titanium,aluminum,niobium (Ti,6Al,7Nb) alloy, air-abraded with alumina, and bonded with 24 combinations of eight metal conditioners (Acryl Bond, ACB; All-Bond 2 Primer B, ABB; Alloy Primer, ALP; Cesead II Opaque Primer, COP; Metafast Bonding Liner, MBL; Metal Primer II, MPII; MR Bond, MRB; Super-Bond liquid, SBL) and three autopolymerizing methacrylic resins (Repairsin, RE; Super-Bond C & B, SB; Tokuso Rebase; TR). Unprimed specimens were used as controls. Shear bond strengths were determined both before and after thermocycling (4,60°C, 20, 000 cycles). The ALP-SB group recorded the greatest post-thermocycling bond strength (21.8 MPa) followed by the COP-SB group (17.8 MPa) and the MPII-SB group. The post-thermocycling bond strengths of the unprimed-SB group and the ALP-RE group were statistically comparable. No significant differences were found among the nine TR resin groups, and these groups showed the lowest bond strength. In conclusion, the use of one of the three conditioners (ALP, COP, and MPII) in combination with the SB resin is recommended for bonding the Ti,6Al,7Nb alloy. [source] Adhesive bonding of titanium nitride-plated stainless steel for magnetic attachmentsEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 3 2001Yohsuke Taira The purpose of this study was to evaluate adhesive bonding of resin to titanium nitride ion-plated stainless steel in order for magnetic attachments to survive in the oral environment. Two primers, Cesead II Opaque Primer (CPII) and Metal Primer II (MPII), and one bonding agent, Super-Bond C&B (SB), were used. The surfaces of stainless steel disks were ground and then plated with titanium nitride. After the primer and SB resin were applied, a self-curing resin was bonded to the metal surfaces. Shear bond strengths were determined after 24 h of water storage and after 2,000 thermocycles. Titanium nitride ion-plated stainless steel showed bond strength comparable to the non-plated material. After thermocycling, all specimens of the group no primer/no SB were debonded. The bond strengths of groups CPII/no SB, MPII/no SB and no primer/SB were significantly lower bond strengths than groups CPII/SB and MPII/SB. An appropriate combination of primer and bonding agent should be selected when bonding a magnetic attachment to the denture base. [source] Kinetic mechanism for p38 MAP kinase ,FEBS JOURNAL, Issue 18 2005A partial rapid-equilibrium random-order ternary-complex mechanism for the phosphorylation of a protein substrate p38 Mitogen-activated protein kinase alpha (p38 MAPK,) is a member of the MAPK family. It is activated by cellular stresses and has a number of cellular substrates whose coordinated regulation mediates inflammatory responses. In addition, it is a useful anti-inflammatory drug target that has a high specificity for Ser-Pro or Thr-Pro motifs in proteins and contains a number of transcription factors as well as protein kinases in its catalog of known substrates. Fundamental to signal transduction research is the understanding of the kinetic mechanisms of protein kinases and other protein modifying enzymes. To achieve this end, because peptides often make only a subset of the full range of interactions made by proteins, protein substrates must be utilized to fully elucidate kinetic mechanisms. We show using an untagged highly active form of p38 MAPK,, expressed and purified from Escherichia coli[Szafranska AE, Luo X & Dalby KN (2005) Anal Biochem336, 1,10) that at pH 7.5, 10 mm Mg2+ and 27 °C p38 MAPK, phosphorylates ATF2,115 through a partial rapid-equilibrium random-order ternary-complex mechanism. This mechanism is supported by a combination of steady-state substrate and inhibition kinetics, as well as microcalorimetry and published structural studies. The steady-state kinetic experiments suggest that magnesium adenosine triphosphate (MgATP), adenylyl (,,,-methylene) diphosphonic acid (MgAMP-PCP) and magnesium adenosine diphosphate (MgADP) bind p38 MAPK, with dissociation constants of KA = 360 µm, KI = 240 µm, and KI > 2000 µm, respectively. Calorimetry experiments suggest that MgAMP-PCP and MgADP bind the p38 MAPK,,ATF2,115 binary complex slightly more tightly than they do the free enzyme, with a dissociation constant of Kd , 70 µm. Interestingly, MgAMP-PCP exhibits a mixed inhibition pattern with respect to ATF2,115, whereas MgADP exhibits an uncompetitive-like pattern. This discrepancy occurs because MgADP, unlike MgAMP-PCP, binds the free enzyme weakly. Intriguingly, no inhibition by 2 mm adenine or 2 mm MgAMP was detected, suggesting that the presence of a ,-phosphate is essential for significant binding of an ATP analog to the enzyme. Surprisingly, we found that inhibition by the well-known p38 MAPK, inhibitor SB 203580 does not follow classical linear inhibition kinetics at concentrations >,100 nm, as previously suggested, demonstrating that caution must be used when interpreting kinetic experiments using this inhibitor. [source] Properties of 2,2,2-Trifluoroethanol/Water Mixtures: Acidity, Basicity, and DipolarityHELVETICA CHIMICA ACTA, Issue 2 2005Paz Sevilla, Sierra In this report, we focus our attention on the characterization of 2,2,2-trifluoroethanol(TFE)/H2O mixtures and describe their intrinsic parameters; i.e., solvent acidity (SA), solvent basicity (SB), and solvent dipolarity/polarizability (SPP), by the probe/homomorph-couple method for a range of mixtures from 0,100% (v/v) TFE. Variation of these parameters is not linear and has a singular and unpredictable behavior depending on the precise composition of the mixture. Based on these parameters, we describe the TFE-induced changes in some physical properties; i.e., viscosity (,), partial molar volume (V,), density (,), dielectric constant (,), vapor pressure (pv), and spectroscopic properties; i.e., NMR chemical shifts (,(1H)) of TFE Me group for all molar fractions studied. In addition, by means of CD studies, we report that formation of the secondary structure, as percentage of helical content, ,, of a polypeptide, poly(L -lysine), in several TFE/H2O mixtures is adequately described by these mixture parameters. SA, SB, and SPP of TFE/H2O mixtures provide an excellent tool for the interpretation of formation and stability of intramolecular H-bonds, and, thus, of secondary structures in polypeptides. [source] Histologic and biochemical changes during the evolution of chronic rejection of liver allograftsHEPATOLOGY, Issue 3 2002Desley A. H. Neil Criteria for histologic diagnosis of chronic rejection (CR) are based on changes seen late in the disease process that are likely to be irreversible and unresponsive to treatment. Changes occurring during the evolution of CR are less clearly defined. The serial biopsy specimens, failed allografts, and biochemical profiles of 28 patients who underwent retransplantation for CR were examined with the aim of identifying histologic and biochemical features that were present during the early stages of CR. For each case, a point of acute deterioration in liver function tests (LFTs) was identified ("start time" [ST]) that subsequently progressed to graft failure. Biopsy specimens before, at the time of ("start biopsy" [SB]), and after the ST were assessed histologically, and findings were correlated with the biochemical changes. CR resulted from acute rejection (AR) that did not resolve. Centrilobular necroinflammation (CLNI) associated with an elevated aspartate transaminase (AST) level and portal tract features of AR were present at the start. Portal AR features resolved, CLNI persisted, AST level remained elevated, and bilirubin and alkaline phosphatase levels progressively increased throughout the evolution of CR. Portal tracts also showed a loss of small arterial and bile duct branches, with arterial loss occurring early and bile duct loss as a later progressive lesion. Foam cell arteriopathy was rarely seen in needle biopsy specimens. In conclusion, findings from this study may help identify patients at risk of progressing to graft loss from CR at a stage when the disease process is potentially reversible and amenable to treatment. [source] The p38 mitogen-activated protein kinase regulates interleukin-1,-induced IL-8 expression via an effect on the IL-8 promoter in intestinal epithelial cellsIMMUNOLOGY, Issue 4 2003Kuljit Parhar Summary Several lines of evidence implicate the p38 mitogen-activated protein kinase (p38 MAPK) in the proinflammatory response to bacterial agents and cytokines. Equally, the transcription factor, nuclear factor (NF)-,B, is recognized to be a critical determinant of the inflammatory response in intestinal epithelial cells (IECs). However, the precise inter-relationship between the activation of p38 MAPK and activation of the transcription factor NF-,B in the intestinal epithelial cell (IEC) system, remains unknown. Here we show that interleukin (IL)-1, activates all three MAPKs in Caco-2 cells. The production of IL-8 and monocyte chemotactic protein 1 (MCP-1) was attenuated by 50% when these cells were preincubated with the p38 MAPK inhibitor, SB 203580. Further investigation of the NF-,B signalling system revealed that the inhibitory effect was independent of the phosphorylation and degradation of I,B,, the binding partner of NF-,B. This effect was also independent of the DNA binding of the p65 Rel A subunit, as well as transactivation, determined by an NF-,B luciferase construct, using both SB 203580 and dominant,negative p38 MAPK. Evaluation of IL-8 and MCP-1 RNA messages by reverse transcription,polymerase chain reaction (RT,PCR) revealed that the inhibitory effect of SB 203580 was associated with a reduction in this parameter. Using an IL-8,luciferase promoter construct, an effect of p38 upon its activation by both pharmacological and dominant,negative p38 construct co-transfection was demonstrated. It is concluded that p38 MAPK influences the expression of chemokines in intestinal epithelial cells, through an effect upon the activation of the chemokine promoter, and does not directly involve the activation of the transcription factor NF-,B. [source] IL-1, induces stabilization of IL-8 mRNA in malignant breast cancer cells via the 3, untranslated region: Involvement of divergent RNA-binding factors HuR, KSRP and TIAR,INTERNATIONAL JOURNAL OF CANCER, Issue 6 2005Esther A. Suswam Abstract IL-8 plays an integral role in promoting the malignant phenotype in breast cancer, and its production is directly influenced by inflammatory cytokines in the tumor microenvironment. Here, we show that activation of IL-1, receptors on malignant HS578t and MDA-MB-231 breast cancer cells strongly induces IL-8 expression and that RNA stabilization is persistently activated at least 12,24 hr after stimulation. SB 203580 and rapamycin reversed the RNA stabilization effect of IL-1, in a dose-dependent manner, suggesting involvement of the p38/MAP kinase and mTOR pathways. A luciferase reporter assay indicated that the stabilization effect was dependent on cis elements in the 3,-untranslated region (UTR) of the IL-8 transcript. By UV cross-linking, we identified multiple cellular factors that interact with the IL-8 3,UTR, ranging 34,76 kDa. Immunoprecipitation analysis indicated that HuR, KSRP and TIAR bound to one or more loci in the 3,UTR. While the cross-linking patterns were similar, quantitative immunoprecipitation of native IL-8 RNA from IL-1,-stimulated cytoplasmic extract revealed a 20-fold greater association of transcript with the stabilizing factor HuR vs. the destabilizing factor KSRP. In conclusion, IL-1, is a potent cytokine stimulus for IL-8 RNA stabilization in breast cancer cells, possibly by enhanced binding of cytoplasmic HuR to the 3,UTR. Published 2004 Wiley-Liss, Inc. [source] Hypertension, white matter change and response to cholinesterase inhibitors in Alzheimer's diseaseINTERNATIONAL JOURNAL OF GERIATRIC PSYCHIATRY, Issue 7 2005Peter J. Connelly Abstract Background Cholinesterase inhibitors are used to treat mild to moderate Alzheimer's disease. Their role in patients with concurrent cerebrovascular disease has been less well studied, and the influence of vascular risk factors on response to treatment is uncertain. We investigated the effect of hypertension and white matter lesions (WML) on response. Methods A retrospective sample of 160 consecutive out-patients who had blood pressure measured and the presence or absence of WML recorded at baseline and who completed six months treatment with a cholinesterase inhibitor was studied. Subjects scored either zero or one on the Modified Hachinski Ischaemic Scale. Subjects were assessed using the Mini-Mental State Examination (MMSE), the Digit Symbol Substitution test (DSST) and both the Instrumental Activities of Daily Living (IADL) and Social Behaviour (SB) sub-scales of the Nurses Observation Scale for Geriatric Patients (NOSGER). Results 43.9% of the total study population were classified as good responders using our criteria. Neither the presence of hypertension nor the presence of WML alone influenced outcome. However, there was a statistically significant interaction between blood pressure and WML on outcome variables on multiple analysis of variance (MANOVA) (F(4,,139),=,5.60, p,<,0.0005). Subjects with both hypertension and WML deteriorate to a significantly greater extent in IADL and SB scores than any other group (p,<,0.05 in each case). This effect could not be explained by age or by smoking status. Conclusion Our results support the hypothesis that there is an interaction between hypertension and WML that adversely influences functional change during cholinesterase inhibitor treatment. Our results are a contrast to suggestions that subjects with vascular disease show a better response to cholinesterase inhibitors. We recommend careful exploration of factors that may influence outcome. Copyright © 2005 John Wiley & Sons, Ltd. [source] Low-complexity unambiguous acquisition methods for BOC-modulated CDMA signalsINTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS AND NETWORKING, Issue 6 2008Elena Simona Lohan Abstract The new M-code signals of GPS and the signals proposed for the future Galileo systems are of split-spectrum type, where the pseudorandom (PRN) code is multiplied with rectangular sub-carriers in one or several stages. Sine and cosine binary-offset-carrier (BOC) modulations are examples of modulations, which split the signal spectrum and create ambiguities in the envelope of the autocorrelation function (ACF) of the modulated signals. Thus, the acquisition of split-spectrum signals, based on the ambiguous ACF, poses some challenges, which might be overcome at the expense of higher complexity (e.g. by decreasing the step in searching the timing hypotheses). Recently, two techniques that deal with the ambiguities of the ACF have been proposed, and they were referred to as ,sideband (SB) techniques' (by Betz, Fishman et al.) or ,BPSK-like' techniques (by Martin, Heiries et al.), since they use SB correlation channels and the obtained ACF looks similar to the ACF of a BPSK-modulated PRN code. These techniques allow the use of a higher search step compared with the ambiguous ACF situation. However, both these techniques use SB-selection filters and modified reference PRN codes at the receivers, which affect the implementational complexity. Moreover, the ,BPSK-like' techniques have been so far studied for even BOC-modulation orders (i.e. integer ratio between the sub-carrier frequency and the chip rate) and they fail to work for odd BOC-modulation orders (or equivalently for split-spectrum signals with significant zero-frequency content). We propose here three reduced-complexity methods that remove the ambiguities of the ACF of the split-spectrum signals and work for both even and odd BOC-modulation orders. Two of the proposed methods are extensions of the previously mentioned techniques, and the third one is introduced by the authors and called the unsuppressed adjacent lobes (UAL) technique. We argue via theoretical analysis the choice of the parameters of the proposed methods and we compare the alternative methods in terms of complexity and performance. Copyright © 2008 John Wiley & Sons, Ltd. [source] Villous trophoblast growth in pregnancy at high altitudeJOURNAL OF ANATOMY, Issue 5 2002T. M. Mayhew The trophoblastic epithelium of placental villi exhibits continuous turnover. Phases of proliferation, recruitment, maturation, terminal differentiation (apoptosis) and extrusion exist in steady state and occur in distinctive spatial compartments, viz. cytotrophoblast cells (CT), syncytiotrophoblast (ST), syncytial knots (SK), denudation sites (DEN) and syncytial fragments. Hypoxia in vitro stimulates CT proliferation but inhibits recruitment into ST. Pregnancy at high altitude (HA) is associated with reduced birthweight and provides a convenient model of preplacental (hypobaric) hypoxia. HA placentas show impoverished villous growth and changes in the incidences of CT cells and SK regions. Here we examine placentas from Amerindian and nonindigenous women who completed full-term pregnancies at low altitude (LA; 400 m; n = 25) and high altitude (HA; 3600 m; n = 45) in Bolivia. We test the hypothesis that HA pregnancy disturbs the epithelial steady state as reflected in the relative volumes and surfaces of trophoblast compartments. Masson trichrome stained tissue sections and microscopical fields were generated by uniform random sampling. Point and intersection counts were used to estimate the volumes and surface areas of nonsyncytial knots (nonSK), SK regions, syncytial bridges (SB) and denudation sites (DEN). Absolute values were compared by 2-way analyses of variance to resolve altitudinal from ethnic effects. At LA, trophoblast comprised about 85% nonSK, 8% SK, 5% SB and 3% CT by volume. Its maternal surface area comprised about 91% nonSK, 5% SK, 2% SB, and 3% DEN. Apart from CT (the fractional volume of which increased to 4%, P < 0.05), relative volumes of trophoblast compartments did not alter significantly at HA. However, there was a roughly 30% reduction in absolute volume of trophoblast at HA (P < 0.001) which could be explained mainly by a decrease in volume of nonSK regions (P < 0.001). The volume of CT was unaltered. Absolute surface areas of villi also declined at HA (by 20%, P < 0.01) and, again, this was attributed mainly to nonSK. The findings confirm that poor villous growth is partly due to failure of trophoblast to attain the growth seen at LA. The reduced trophoblastic growth occurs despite an increase in relative volume of CT cells (consistent with previously reported increases in proliferative activity) and, probably, by a combination of compromised syncytial fusion and continuing extrusion of syncytial fragments. [source] The amounts and deposition patterns of fibrin-type fibrinoid at the villous surface are altered in pregnancy at high altitudeJOURNAL OF ANATOMY, Issue 5 2002T. M. Mayhew In pregnancy at high altitude, there is preplacental (hypobaric) hypoxia and intrauterine fetal growth is restricted. Previous studies on placentas from Amerindian and nonindigenous women completing term pregnancies at low (LA; 400 m) and high (HA; 3600 m) altitudes in Bolivia showed that HA placentas had smaller surface areas of villi and smaller volumes of fibrin type fibrinoid (FTF). Recently we devised a stereological method for testing whether perivillous FTF (pFTF) is randomly distributed at the surface of villous trophoblast. Here the method is applied to test 2 experimental hypotheses: [1] deposition of pFTF is nonrandom regardless of altitude and [2] deposition patterns differ between altitudes. Uniform random samples of microscopical fields were drawn from Masson trichrome stained sections and intersection counts used to estimate the surface areas of, and patterns of pFTF on, 4 regions of trophoblast: nonsyncytial knots (nonSK), syncytial knots (SK), syncytial bridges (SB) and denudation sites (DEN). Absolute areas were compared by 2-way analyses of variance. Expected and observed distributions were compared by (2 and contingency table analyses. At LA the mean (SEM) volume of FTF was 8.4 (1.54) cm3 and villous surface area was 7.0 (0.43) m2. At HA FTF volume was reduced by about 50% (P < 0.01) and villous surface by 20% (P < 0.01). The surface composition of trophoblast in LA placentas was nonSK (91%), SK (5%) and SB and DEN (both less than 3%). Relative surfaces were not significantly altered in HA placentas but, due to the impoverished growth of villi at HA, the changes represented a real decline in absolute surface of nonSK. At HA, the total surface of pFTF on trophoblast decreased by about 40%, from 4430 (564) cm2,2570 (406) cm2 (P < 0.01). At both altitudes pFTF deposition was preferentially found at DEN (12-fold greater than expected for a random distribution). Pattern differences were detected between altitudes. In HA placentas the amount of pFTF deposited on nonSK regions was about 45% less (P < 0.05); apparent changes on SK and SB regions were not significant. These histometric findings suggest that the coagulation-fibrinolysis steady state is altered at HA and favours greater fibrinolysis. At least some of the fibrinolytic or anticoagulant activity seems to reside in or on thinner regions of villous trophoblast and the placenta may be a relatively privileged site in terms of fibrinolysis. Also, reduced deposition of pFTF is probably linked to changes in the steady state of trophoblast turnover which seems to be perturbed in HA pregnancies. [source] Regulation of CYP1A2 by histone deacetylase inhibitors in mouse hepatocytesJOURNAL OF BIOCHEMICAL AND MOLECULAR TOXICOLOGY, Issue 3 2004Bohwan Jin Abstract Cytochrome P450 1A2 (CYP1A2) is constitutively expressed in the mouse liver, but the constitutive expression progressively declines to an undetectable level in isolated hepatocytes. In this study, CYP1A2 was induced in hepatocytes exposed to the histone deacetylase inhibitors trichostatin A (TSA) and sodium butyrate (SB), but only well after constitutive CYP1A2 expression was silenced. However, cotreatment with the arylhydrocarbon receptor (AhR) ligand 2,3,7,8-tetrachlorodibenzo- p -dioxin (TCDD) and either TSA or SB reduced the induction of CYP1A2 with the same time course as TSA or SB increased its induction. These results suggest that histone modification is involved in CYP1A2 regulation in hepatocytes through pathways that are independent of AhR. © 2004 Wiley Periodicals, Inc. J Biochem Mol Toxicol 18:131,132, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20017 [source] Effects of a peripheral enamel bond on the long-term effectiveness of dentin bonding agents exposed to water in vitroJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 1 2008Andre F. Reis Abstract This study evaluated the effects of water exposure on the in vitro microtensile bond strength (,TBS) of etch-and-rinse and self-etching adhesives to human dentin over a 1-year storage period. Five adhesive systems used were as follows: a one-step self-etching adhesive (One-up Bond F-OB), two two-step self-etching primers (Clearfil SE Bond-SE and Clearfil Protect Bond-CP), and two etch-and-rinse adhesives (Single Bond-SB and Prime&Bond NT-PB). Dentin surfaces were bonded, restored, and assigned to four subgroups, according to the degree of water exposure: 24 h of peripheral water exposure (24 h-PE) (having circumferential enamel); and 1 year of peripheral exposure (1 yr-PE), direct exposure (1 yr-DE) (dentin directly water-exposed), or directly exposed to oil only (no water exposure) (1 yr-DOE). A composite-enamel bond adjacent to the restoration is determined if the water exposure was peripheral or direct. After storage periods, specimens were serially sectioned, trimmed to an hourglass shape with a cross-sectional area of 1 mm2 at the interface, and tested in tension. Results were analyzed by two-way ANOVA and Tukey test (, = 0.05). No difference was found between 24 h-PE and 1 yr-PE for OB, CP, SB, and PB. However, ,TBS values significantly dropped after 1 yr-DE for SE, CP, SB, and PB. A decreased ,TBS was seen in SE after 1 yr-PE, but no differences existed between 1 yr-PE and 1 yr-DE. Similar or increased ,TBS values were noted in 1 yr-DOE for all adhesives. Water-storage for 1 year significantly decreased ,TBS for all adhesives. However, except for SE, the presence of a peripheral composite-enamel bond seemed to reduce the degradation rate in resin-dentin interfaces for all materials. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008 [source] Comparative corrosion performance of black oxide, sandblasted, and fine-drawn nitinol wires in potentiodynamic and potentiostatic tests: Effects of chemical etching and electropolishingJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2004Svetlana Shabalovskaya Abstract The corrosion performance of sandblasted (SB) and smooth fine-drawn (FD) medical-use nitinol wires was compared with the performance of wires with black oxide (BO) formed in air during their manufacture. Potentiodynamic and ASTM F746 potentiostatic tests in a 0.9 % NaCl solution were conducted on wires in their as-received, chemically etched, aged in boiling water, and electropolished states. As-received wires with various surface finishes revealed breakdown potentials in the range from ,100 mV to +500 mV; similar passive current density, 10,6 A/cm2; and a wide hysteresis on the reverse scan, demonstrating strong susceptibility to localized corrosion. Chemically etched wires with original black oxide displayed consistent corrosion performance and surpassed, in corrosion resistance, electropolished wires that showed significantly lower breakdown (400,700 mV) and localized corrosion potentials (,,50 to +113 mV). Sandblasted and fine-drawn wires exhibited rather inconsistent corrosion behavior. In potentiodynamic tests these wires could perform with equal probability either on the level of pretreated BO wires or rather similar to as-received wires. Both SB and FD wires revealed low breakdown potentials in the PS regime. SEM analysis performed before tests indicated that sandblasting was not efficient for the complete removal of the original scaling, and fine drawing aggravated the situation, resulting in a persistent scaling that contributed to the inferior corrosion performance. Inclusions (oxides, carbides, and oxidized carbides) inherited from the bulk and retained on electropolished surfaces are the cause of their inferior performance compared to chemically etched surfaces. In electropolished wires corrosion was initiated around inclusions. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 69B: 223,231, 2004 [source] Mechanical Heart Valves in SeptuagenariansJOURNAL OF CARDIAC SURGERY, Issue 1 2008Ch.M., F.E.T.C.S., F.R.C.S., R. Ascione M.D. Methods: The study was carried out in a tertiary regional hospital in South-West England. Study 1: Consecutive series of 567 patients undergoing Sorin Bileaflet (SB) mechanical valve implant (437 patients < 70 years; 130 patients , 70 years). Study 2: 113 septuagenarians undergoing biological implant matched on age, valve type, concomitant coronary surgery, and operative priority to the SB septuagenarian group. Main outcome measures included in-hospital mortality and morbidity and mid-term valve-related outcome. Results: Study 1: Septuagenarians were more likely to present with coronary disease, and to undergo coronary surgery (p < 0.01). In-hospital mortality was 2.8% and 2.3% (p = 0.79) and neurological complications 1.4% versus 3.8% (p = 0.026) in the younger and older groups, respectively. Valve-related mortality at two years was 1.8% (95%CI, 0.8% to 3.6%) and 4.8% (95% CI, 2.0% to 9.7%); cumulative three- year incidence of thromboembolic or major hemorrhagic event was 8.3% (95% CI, 5.7% to 12.0%) and 4.6% (95% CI, 1.7% to 12.4%) in the younger and older groups, respectively. Study 2: In-hospital mortality was 1.8% and 7.1% in the SB and biological groups, respectively (ratio 0.25; 95% CI, 0.05 to 1.18, p = 0.058). The incidence of acute renal failure was greater in the biological group (risk ratio 0.30; 95% CI, 0.09 to 0.98, p = 0.035). There was no difference in mid-term valve-related mortality between groups (hazard ratio 0.53; 95% CI, 0.18 to 1.52, p = 0.24). Conclusion: The performance of SB valve in septuagenarians seems to be effective with no increased risk of in-hospital mortality, bleeding, or thromboembolic events. [source] Electrocardiographic Findings, Device Therapies, and Comorbidities in Octogenarian Implantable Defibrillator RecipientsJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 3 2010JAMES D. DANIELS M.D. Implantable Defibrillators in Octogenarians.,Background: The use of implantable cardioverter-defibrillators (ICDs) in octogenarians is poorly defined. Objective: To assess baseline electrocardiographic (ECG) findings, arrhythmia episodes, and development of severe nonarrhythmic illness or death in patients aged ,80 years at ICD implantation, and to compare them with younger patients. Methods: Medical records and device interrogations for 199 patients ,70 years old who underwent ICD implantation were reviewed. Patients were divided into 3 groups based on age at the time of implant: age 70,74 (group 1; 88 patients), age 75,79 (group 2; 67 patients), and age ,80 (group 3; 44 patients). Results: ECGs: Octogenarians were more likely to have sinus bradycardia (SB) (P = 0.047) and left bundle branch block (LBBB) (P = 0.043) compared to younger patients. There was no difference among groups in the proportion of patients with atrial fibrillation or any degree of AV block. Therapies: There was no difference between age groups in any therapy (P = 0.78), appropriate therapy (P = 0.54), or inappropriate therapy (P = 0.21) per patient-year. There was no difference between groups in time-to-first therapy of any type (P = 0.71). Nonarrhythmic death/morbidity: There was no difference between groups in time to death or serious illness. Conclusion: Our study is the first to evaluate in detail the therapies received by octogenarians after ICD placement. The higher incidence of SB and LBBB might influence the number of pacing sites in octogenarian patients. Very elderly patients have similar rates of arrhythmic episodes and development of severe comorbidities as septuagenarians, and they should not be denied ICD implantation based solely on age. (J Cardiovasc Electrophysiol, Vol. 21, pp. 236,241, March 2010) [source] | |||||||||||||||||||||||||||||||