1,817 research outputs found
Evaluation of the first automated thyroglobulin assay
No full textThe aim of this study was to investigate technical and analytical performance of the first automated thyroglobulin (Tg) assay (DPC-Immulite(R); Diagnostic Products Corporation, Los Angeles, USA). In imprecision studies using several human serum pools ranging from 21 to 58 replicates, a coefficient of variation of 9.0 % was obtained at a mean Tg concentration of 0.84 ng/ml and of 6.1 % at a Tg concentration of 62.1 ng/ml. In a method comparison with a non-automated assay (BRAHMS LUMItest Tg(R), BRAHMS, Berlin, Germany) using 383 sera of 303 patients with thyroid carcinoma, regression analysis according to Passing and Bablock yielded in the following equation: Immulite Tg=1.6 x BRAHMS Tg - 0.1 ng/ml (Pearson's r=0.979). Sera obtained from 59 patients with thyroid carcinoma enabled comparative follow-up studies; in all cases qualitative agreement was found with regard to increase or decrease of serum Tg; in eight cases, however, Tg was detected with the Immulite assay but not with the BRAHMS assay. Further follow-up proved the presence of thyroid tissue in these patients. From these and further methodological data (dilution linearity, interference studies, carry-over study, high-dose hook properties, and short report time) it is concluded that the DPC-Immulite Tg assay meets the requirements of routine diagnostic use
Mechanical, thermal and flame retardant properties of poly (lactic acid) / poly (methyl methacrylate) blends / Teoh, Ee Lian
No full textPoly(lactic acid)/poly(methyl methacrylate) (PLA/PMMA) blends were prepared by melt compounding technique. Phosphorus-based flame retardant (FR) was used together with β-cyclodextrin (CD) to improve the flame resistant and thermal properties of PLA/PMMA blends. In the first stage, study was focus on the evaluation on the miscibility of PLA/PMMA blends at various blending ratio (i.e., 80/20, 60/40, 40/60, and 20/80). The evaluation was performed through thermal properties measurement [i.e., differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA)] and solvent uptake experiment. Single glass transition temperature (Tg) was detected on PLA/PMMA blends over entire composition range during DMA measurement. The solvent uptake experiment showed that PLA/PMMA20 blend exhibited smallest interaction parameter (χ12 = −0.03) according to the calculation of Flory-Huggins interaction parameter (χ12). In the second stage, phosphorus-based flame retardant (FR; 20 part per hundred resin) was added to improve the flame resistant and thermal properties of PLA/PMMA blends at blending ratio of 80/20 and 60/40.UL-94 vertical burning test and limiting oxygen index (LOI) were conducted to characterize the flame resistant properties of the blends, while thermogravimetric analyzer (TGA) was used to determine the thermal stability of the blends. Both of the PLA/PMMA20/FR and PLA/PMMA40/FR successfully achieved V-0 rating in the burning test, regardless of the PLA/PMMA blending ratio. TGA results showed that addition of FR had accelerated the thermal decomposition of PLA/PMMA20/FR and PLA/PMMA40/FR blends at low temperature, but improved the thermal stability of blends at high temperature. Higher LOI value was attained by PLA/PMMA20/FR (i.e., 31.3%) than PLA/PMMA40/FR (i.e., 28.0%), indicating PLA/PMMA20/FR having higher flame resistant properties than PLA/PMMA40/FR. In the third stage, half of the FR was replaced by CD and the efficiency of the combination in improving flame resistant and thermal properties of PLA/PMMA blend was investigated. During flammability tests, dripping behavior of the PLA/PMMA20/FR/CD was improved while maintaining its flame retardancy (i.e., UL-94 V-0; LOI = 29.3%). Higher maximum degradation temperature (Tmax) was obtained for PLA/PMMA20/FR/CD during TGA measurement, suggested the thermal degradation was delayed in the presence of CD. Scanning electron microscope (SEM) showed an extensive and compact char layer was formed on the burning surface of PLA/PMMA20/FR/CD, proving that CD could be an effective adjuvant for FR in improving flame retardancy of PLA/PMMA20/FR/CD
Bulk viscosity in F(T, TG) gravity
No full textThe present paper is devoted to exploring the effect of bulk viscosity in the context of F(T, TG) gravity. We consider a time-dependent viscosity model with a particular expression of Hubble parameter. We evaluate viscous effective equation of state parameter for three well-known F(T, TG) models. The behavior of the accelerated expanding universe is explored graphically through the viscous equation of state parameter. This parameter indicates the phantom-dominated era as well as crosses the phantom divide line for all three models. We conclude that the universe shows a transition from quintessence to phantom region in the presence of bulk viscosity.The presentation of the authors' names and (or) special characters in the title of the pdf file of the accepted manuscript may differ slightly from what is displayed on the item page. The information in the pdf file of the accepted manuscript reflects the original submission by the author
() Topology of unimolecular G-quadruplex adopted by dG(TG) and -ion-binding sites
No full text<p><b>Copyright information:</b></p><p>Taken from "NMR evaluation of ammonium ion movement within a unimolecular G-quadruplex in solution"</p><p>Nucleic Acids Research 2007;35(8):2554-2563.</p><p>Published online 4 Apr 2007</p><p>PMCID:PMC1895886.</p><p>© 2007 The Author(s)</p> The three binding sites are labeled as O, I and O. The guanine bases are shown as numbered rectangles, where cyan and magenta rectangles represent nucleobases in and conformation, respectively. () Birds-eye view of a ion above an individual G-quartet
Competition of the 13 bp substrate duplexes and the Tg-containing duplexes in the Endo III reaction
No full text<p><b>Copyright information:</b></p><p>Taken from "Synthesis and characterization of oligonucleotides containing 2′-fluorinated thymidine glycol as inhibitors of the endonuclease III reaction"</p><p>Nucleic Acids Research 2006;34(5):1540-1551.</p><p>Published online 17 Mar 2006</p><p>PMCID:PMC1409675.</p><p>© The Author 2006. Published by Oxford University Press. All rights reserved</p> The P-labeled substrates without fluorine were incubated with Endo III in the presence of the competitors containing Tg. The amounts of the nicked products (standardized to those without the competitors) were plotted against the concentrations of the competitor. Open circles, P-5-Tg + 5-Tg; filled circles, P-5-Tg + 5-Tg; open triangles, P-5-Tg + 5-Tg; filled triangles, P-5-Tg 5-Tg
DNA fusion gene vaccination mobilizes effective anti-leukemic cytotoxic T lymphocytes from a tolerized repertoire
No full textThe majority of known human tumor-associated antigens derive from non-mutated self proteins. T cell tolerance, essential to prevent autoimmunity, must therefore be cautiously circumvented to generate cytotoxic T cell responses against these targets. Our strategy uses DNA fusion vaccines to activate high levels of peptide-specific CTL. Key foreign sequences from tetanus toxin activate tolerance-breaking CD4+ T cell help. Candidate MHC class Ibinding tumor peptide sequences are fused to the C terminus for optimal processing and presentation. To model performance against a leukemia-associated antigen in a tolerized setting, we constructed a fusion vaccine encoding an immunodominant CTL epitopederived from Friend murine leukemia virus gag protein (FMuLVgag) and vaccinated tolerant FMuLVgag-transgenic (gag-Tg) mice. Vaccination with the construct induced epitopespecificIFN-c-producing CD8+ T cells in normal and gag-Tg mice. The frequency and avidity of activated cells were reduced in gag-Tg mice, and no autoimmune injury resulted. However, these CD8+ T cells did exhibit gag-specific cytotoxicity in vitro and in vivo. Also, epitope-specific CTL killed FBL-3 leukemia cells expressing endogenous FMuLVgag antigen and protected against leukemia challenge in vivo. These results demonstrate a simple strategy to engage anti-microbial T cell help to activate epitope-specific polyclonal CD8+ T cell responses from a residual tolerized repertoire
Dechlorination of waste polyvinyl chloride (PVC) via its co-pyrolysis with Ca(OH)2: A TG-IR-GCMS investigation
No full textBeing the most deployed thermoplastic worldwide, waste polyvinyl chloride (PVC) generation is expected to increase by about 80% over the next couple of decades. Chlorine toxication during the incineration process is a menace for waste handling facilities though various PVC management is in place. Hence, effective chloride capture is considered the primary focus during PVC pyrolysis rather than harnessing the latent hydrocarbons in any form of energy. In order to simulate a real-world situation wherein the chlorine content is proficiently removed from waste PVC using affordable additives, the state-of-the-art online TG-IR-GCMS approach was used to examine the PVC thermal degradation products in the presence and absence of Ca(OH)2. In both cases, the TG analysis revealed twin degradation phases with the simultaneous IR spectral analysis verifying that the HCl release was limited to the first stage with a mass loss of ∼60%; most notably benzene being the other major product with 81.59% relative area as endorsed by GCMS analysis. In the second stage, further PVC chains unzipping generated several other aromatic products upon the Diels–Alder reactions of intramolecular cyclization such as toluene, xylene and other benzene derivatives. The PVC co-pyrolysis with Ca(OH)2 reduced the HCl formation significantly due to the dissociative adsorption of HCl gradually over the calcium surface converting Ca(OH)2 into calcium oxide and eventually into CaCl2 as verified by the XRD crystallinity analysis and surface morphology and elemental mapping via SEM-EDX analysis
Aromatic () and imino () regions of H NMR spectrum of form of dG(TG) G-quadruplex at 298 K
No full text<p><b>Copyright information:</b></p><p>Taken from "NMR evaluation of ammonium ion movement within a unimolecular G-quadruplex in solution"</p><p>Nucleic Acids Research 2007;35(8):2554-2563.</p><p>Published online 4 Apr 2007</p><p>PMCID:PMC1895886.</p><p>© 2007 The Author(s)</p> Plot of 2D N–H HSQC spectrum (). The cross-peak corresponding to ions in bulk is labeled as B, while those residing at the binding sites within the G-quadruplex are labeled as O, O and I
Gradient interphases between high-Tg epoxy and polyetherimide for advanced joining processes
No full textAdhesive joining of carbon fibre reinforced polymer (CFRP) is cumbersome due to the careful surface preparation required and multiple validation steps to certify adhesion quality. Further these joints are often supplemented by mechanical fastenings add weight whilst also localising bearing stress. As an alternative technique, CFRP parts can be functionalized with thermoplastic surfaces during manufacture to enable cost-effective welding of composite structures. In the process of manufacturing the CFRP, curing an epoxy resin in the presence of the functionalising thermoplastic polymer can lead to local dissolution of the latter in the epoxy, followed by a reaction-induced phase separation. This results in a thermosetting-thermoplastic interphase featuring gradient concentrations and a multiphase morphology, which promotes load transfer between the thermosetting matrix and the thermoplastic joint. The aim of the work presented in this paper was to investigate interphase formation between high-Tg epoxy and polyetherimide (PEI) at different curing temperatures. The morphology was characterised using scanning electron microscopy and the composition of the interphase was quantified through Raman spectroscopy. The curing experiments indicated that temperature has a significant effect on the interphase morphology and led to two different biphasic morphologies which generally increased in size with increasing curing temperature. This suggests that the size of the gradient interphase can be tailored through the curing process, which is as a fundamental step in optimising the structural performance of welded joints with PEI-functionalized epoxy-based CFRPs.Aerospace Manufacturing TechnologiesStructural Integrity & Composite
An exponential convergence estimate for analog neural networks with delay
No full textA componentwise estimate of exponential convergence is obtained for a class of delayed Hopfield type neural networks by using a method based on a comparison principle of delay differential systems. The method is simple and straightforward in analysis, without resorting to any Lyapunov functionals. The result shows explicitly the effect of time delay on exponential decay rate of the networks and is of practical significance for designing fast and stable neural networks. Some existing results via Lyapunov functional method and linear analysis are found to be special cases of the present result. (C) 2001 Elsevier Science B.V. All rights reserved.Physics, MultidisciplinarySCI(E)42ARTICLE1-2113-11828
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