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RT
Kinds of RT Terms modified by RT Selected AbstractsShock tube study of 1,3,5-triazine dissociation and relaxation and relaxation of pyrazineINTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 4 2010Hui Xu The three-body dissociation of 1,3,5-triazine (s-triazine, s-C3H3N3 , 3HCN) has been observed in incident shock waves with the laser-schlieren technique. The experiments use 5% triazine/Kr and cover 1630,2350 K for 100,600 Torr. These experiments show dissociation rates with strong falloff and a slight but fully expected pressure dependence. The dissociation is without secondary reaction save for a possible, but rather unlikely, contribution from the isomerization HCN , HNC. Electronic structure calculations of the transition-state properties (G3B3, HL1, Eo = 84.6 kcal/mol) are used to construct a Rice,Ramsperger,Kassel,Marcus (RRKM) model whose fit to the rate measurements suggests a ,,E,down of 1200 cm,1. However, a seemingly better fit is achieved using the barrier of 81 kcal/mol proposed by Dyakov et al. (J. Phys. Chem. A 2007, 111, 9591,9599). With this barrier k, (s,1) = 5.3 × 1016 exp(,86.6(kcal/mol)/RT), and the fit now accepts the more routine ,,E,down = 126(T/298)0.9. It seems the dissociation most likely occurs by a direct, one-step, "triple" dissociation to 3HCN, although the present experiments cannot rule out a multistep process. Vibrational relaxation of the triazine was also examined in 5% and 20% mixtures with Kr over 770,1500 K for pressures between 6 and 14 Torr. Relaxation is very fast, with a slight inverse temperature dependence, P, rising from 100 to 200 ns-atm over the full temperature range. Integrated gradients are in good accord with calculated total changes in density, indicating a single exponential relaxation. A separate investigation of relaxation in the related molecule pyrazine (500,1300 K, in 1% and 5% in Kr, between 13 and 66 Torr) is included. Again relaxation is rapid, but here the temperature dependence seems more normal, the relaxation times decreasing slightly with temperature. © 2010 Wiley Periodicals, Inc. Int J Chem Kinet 42: 211,220, 2010 [source] Grain-Boundary Diffusion of Cr in Pure and Y-Doped AluminaJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 5 2007K. Bedu-Amissah The diffusive transport of chromium in both pure and Y-doped fine-grained alumina has been investigated over the temperature range 1250°,1650°C. From a quantitative assessment of the chromium diffusion profile in alumina, as obtained from electron microprobe analysis, it was found that yttrium doping retards cation diffusion in the grain-boundary regime by over an order of magnitude. The Arrhenius equations for the undoped and Y-doped samples were determined to be: ,Db=(4.77±0.24) × 10,7 exp (,264.78±47.68 (kJ/mol)/RT)(cm3/s) and ,Db=(6.87±0.18) × 10,8 exp (,284.91±42.57 (kJ/mol)/RT)(cm3/s), respectively. Finally, to elucidate the mechanism for this retardation, the impact of yttrium doping on diffusion activation energies and prefactors was examined. [source] Conformational Relaxation of p -Phenylenevinylene Trimers in Solution Studied by Picosecond Time-Resolved FluorescenceCHEMPHYSCHEM, Issue 18 2007Roberto E. Di Paolo Dr. Abstract Two p -phenylenevinylene (PV) trimers, containing 3,-methylbutyloxyl (in MBOPV3) and 2,-ethylhexyloxyl (in EHOPV3) side chains, are used as model compounds of PV-based conjugated polymers (PPV) with the purpose of clarifying the origin of fast (picosecond time) components observed in the fluorescence decays of poly[2-methoxy-5-(2,-ethylhexyloxy)- p -phenylenevinylene] (MEH-PPV). The fluorescence decays of MBOPV3 and EHOPV3 reveal the presence of similar fast components, which are assigned to excited-state conformational relaxation of the initial population of non-planar trimer conformers to lower-energy, more planar conformers. The rate constant of conformational relaxation kCR is dependent on solvent viscosity and temperature, according to the empirical relationship kCR=a,o,,,exp(,,E,/RT), where a,o,, is the frequency factor, ,o is the pre-exponential coefficient of viscosity, E, is the activation energy of viscous flow. The empirical parameter ,, relating the solvent microscopic friction involved in the conformational change to the macroscopic solvent friction (,=1), depends on the side chain. The fast component in the fluorescence decays of MEH-PPV polymers (PPVs), is assigned to resonance energy transfer from short to longer polymer segments. The present results call for revising this assignment/interpretation to account for the occurrence of conformational relaxation, concurrently with energy transfer, in PPVs. [source] Validation of a thermal decomposition mechanism of formaldehyde by detection of CH2O and HCO behind shock wavesINTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 3 2004Gernot Friedrichs The thermal decomposition of formaldehyde was investigated behind shock waves at temperatures between 1675 and 2080 K. Quantitative concentration time profiles of formaldehyde and formyl radicals were measured by means of sensitive 174 nm VUV absorption (CH2O) and 614 nm FM spectroscopy (HCO), respectively. The rate constant of the radical forming channel (1a), CH2O + M , HCO + H + M, of the unimolecular decomposition of formaldehyde in argon was measured at temperatures from 1675 to 2080 K at an average total pressure of 1.2 bar, k1a = 5.0 × 1015 exp(-308 kJ mol,1/RT) cm3 mol,1 s,1. The pressure dependence, the rate of the competing molecular channel (1b), CH2O + M , H2 + CO + M, and the branching fraction , = k1a/(kA1a + k1b) was characterized by a two-channel RRKM/master equation analysis. With channel (1b) being the main channel at low pressures, the branching fraction was found to switch from channel (1b) to channel (1a) at moderate pressures of 1,50 bar. Taking advantage of the results of two preceding publications, a decomposition mechanism with six reactions is recommended, which was validated by measured formyl radical profiles and numerous literature experimental observations. The mechanism is capable of a reliable prediction of almost all formaldehyde pyrolysis literature data, including CH2O, CO, and H atom measurements at temperatures of 1200,3200 K, with mixtures of 7 ppm to 5% formaldehyde, and pressures up to 15 bar. Some evidence was found for a self-reaction of two CH2O molecules. At high initial CH2O mole fractions the reverse of reaction (6), CH2OH + HCO , CH2O + CH2O becomes noticeable. The rate of the forward reaction was roughly measured to be k6 = 1.5 × 1013 cm3 mol,1 s,1. © 2004 Wiley Periodicals, Inc. Int J Chem Kinet 36: 157,169 2004 [source] Pulsed laser polymerization study of the propagation kinetics of acrylamide in waterJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 7 2005Shane A. Seabrook Abstract Pulsed laser polymerization was used in conjunction with aqueous-phase size exclusion chromatography with multi-angle laser light scattering detection to determine the propagation rate coefficient (kp) for the water-soluble monomer acrylamide. The influence of the monomer concentration was investigated from 0.3 to 2.8 M, and kp decreased with increasing monomer concentration. These data and data for acrylic acid in water were consistent with this decrease being caused by the depletion of the monomer concentration by dimer formation in water. Two photoinitiators, uranyl nitrate and 2,2,-azobis(2-amidinopropane) (V-50), were used; kp was dependent on their concentrations. The concentration dependence of kp was ascribed to a combination of solvent effects arising from association (thermodynamic effects) and changes in the free energy of activation (effects of the solvent on the structure of the reactant and transition state). Arrhenius parameters for kp (M,1 s,1) = 107.2 exp(,13.4 kJ mol,1/RT) and kp (M,1 s,1) = 107.1 exp(,12.9 kJ mol,1/RT) were obtained for 0.002 M uranyl nitrate and V-50, respectively, with a monomer concentration of 0.32 M. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1357,1368, 2005 [source] Electric-oxidation kinetics of molybdenite concentrate in acidic NaCl solutionTHE CANADIAN JOURNAL OF CHEMICAL ENGINEERING, Issue 6 2009Cao Zhan-fang Abstract The electric-oxidation kinetics of molybdenite concentrate in NaCl electrolyte was investigated in this study. The effects of liquid-to-solid ratio, stirring speed, and concentration of NaCl on the dissolution rate were determined. It was found that the dissolution rate increases with increase in liquid-to-solid ratio, stirring speed, and concentration of NaCl. A shrinking particle model is presented to describe the dissolution and to analyse the data. The apparent activation energy of this dissolution process was found to be 8.2,kJ/mol; it was established that the leaching process is mainly controlled by diffusion, and the kinetics formula of this research system can be expressed as: . Dans cette étude, on examine la cinétique de l'oxydation électrique d'un concentré de molybdénite dans un électrolyte de NaCl. Les effets du rapport liquide-solide, de la vitesse d'agitation et de la concentration de NaCl sur le taux de dissolution ont été déterminés. Il a été découvert que le taux de dissolution augmente avec le rapport liquide-solide, la vitesse d'agitation et la concentration de NaCl. Un modèle de contraction de particule est présenté pour décrire la dissolution et analyser les données. L'énergie d'activation apparente de ce processus de dissolution a été évaluée à 8,2KJ/mol. Il a été établi que le processus de lixiviation est principalement contrôlé par diffusion et la formule cinétique de ce système de recherche peut être exprimée sous la forme: k,=,0,0207C exp(,8200/RT). [source] Atypical teratoid/rhabdoid tumor: Cytology and differential diagnosis in adultsDIAGNOSTIC CYTOPATHOLOGY, Issue 1 2004Jack Raisanen M.D. Abstract Atypical teratoid/rhabdoid tumors (AT/RTs) are malignant intracranial neoplasms that usually occur in the posterior fossa of children. They are characterized by cells with paranuclear rhabdoid inclusions, a mesenchymal and epithelial immunohistochemical profile, and 22q deletions with inactivation of the INI1/hSNF5 gene. Although they usually occur in young children, AT/RTs are being recognized in adults with increasing frequency. We report the cytologic features of an AT/RT from the cerebellum of a 45-year-old man and discuss the differential diagnosis in adults. Diagn. Cytopathol. 2004;31:60,63. © 2004 Wiley-Liss, Inc. [source] Melanocytic medulloblastoma with ganglioneurocytomatous differentiation: A case reportNEUROPATHOLOGY, Issue 1 2009Kanako C. Kubota Melanotic or melanocytic medulloblastoma is a rare variant of medulloblastoma, especially when the tumor shows advanced neuronal differentiation. We report a case of this tumor, which developed in the cerebellar vermis in an 8-year-old girl. Initial biopsy specimens were identified as classical medulloblastoma with a high MIB1 index. Surgical removal of the tumor was performed after chemo-radiotherapy, and black pigments were noticed on the tumor surface. Histologically, the tumor was composed of classical medulloblastoma with the presence of pigmented epithelial cells forming tubules and clusters. Immunohistochemically, the pigmented tumor cells were positive for S100 protein, HMB45, and MART1, indicating that the pigments were derived from melanosomes, and these features were compatible with melanocytic medulloblastoma. Interestingly, some of the non-pigmented or amelanotic tumor cells were also positive for HMB45 and S100 protein. Although the tumor showed an unusual cell combination, it was distinguished from atypical teratoid/rhabdoid tumor (AT/RT) by nuclear expression of INI1/BAF45 protein. The tumor also possessed ganglion-like cells within the neuropil matrix, which resembled small mature ganglion cells, and was consequently designated as ganglioneurocytoma. The melanotic medulloblastoma and part of the ganglioneurocytomatous area were fused with each other. Hence, the present case provides new information indicating that melanocytic medulloblastoma differs from AT/RT, and that it can exhibit advanced neuronal differentiation. In addition, reduction of the tumor MIB1 index was observed after chemo-radiotherapy. [source] Chromosome 22q Deletions in Atypical Teratoid/Rhabdoid Tumors in AdultsBRAIN PATHOLOGY, Issue 1 2005Jack Raisanen MD Atypical teratoid/rhabdoid tumors (AT/RTs) are rare, malignant brain tumors that usually occur in the posterior fossa. Both AT/RT and the analogous tumor outside the brain, malignant rhabdoid tumor, share a polyphenotypic immunoprofile and frequent 22q deletions with inactivation of the INI1/hSNF5 gene. Reports, so far, indicate that AT/RTs occur almost exclusively in children, most of whom are 5-years-old or less. The rarity of the tumor and the polyphenotypic immunoprofile, characterized by antigen expression that is often patchy, make diagnosis in adults difficult and controversial. We describe three AT/RTs in adults in which the diagnoses were supported by detection of 22q11.2 deletions, INI1 mutation and/or loss of INI1 protein expression. Two patients were female, ages 20 and 31 and one was male, age 45. Two tumors occurred in the sella or sellar region and one in the cerebellum. In all cases, fluorescence in situ hybridization with probes to the BCR (22q11.2) and NF2 (22q12) regions of chromosome 22 revealed single copy deletions of BCR with normal dosages of NF2 and, in all cases, immunohistochemistry demonstrated loss of INI1 protein expression. In one case, a single base pair deletion was detected in the INI1/hSNF5 gene. These molecular findings confirm the occurrence of AT/RTs in adults. Although rare, AT/RT should be considered in the differential diagnosis of poorly differentiated intracranial tumors in adults. [source] A novel equation of state (EOS) for prediction of solute solubility in supercritical carbon dioxide: Experimental determination and correlationTHE CANADIAN JOURNAL OF CHEMICAL ENGINEERING, Issue 6 2009Sh. Jafari Nejad Abstract Solubility data of organophosphorous metal extractants in supercritical fluids (SCF) are crucial for designing metal extraction processes. We have developed a new equation of state (EOS) based on virial equation including an untypical parameter as BP/RT, reduced temperature and pressure for prediction of solute solubility in supercritical carbon dioxide (SC CO2). Solubility experimental data (solubility of tributylphosphate in SC CO2) were correlated with the two cubic equations of state (EOS) models, namely the Peng,Robinson EOS (PR-EOS) and the Soave,Redlich,Kwong EOS (SRK-EOS), together with two adjustable parameter van der Waals mixing and combining rules and our proposed EOS. The AARD of our EOS is significantly lower than that obtained from the other EOS models. The proposed EOS presented more accurate correlation for solubility data in SC CO2. It can be employed to speed up the process of SCF applications in industry. Les données de solubilité d'extractants de métaux organo-phosphorés dans des fluides supercritiques (FSC) sont cruciales pour concevoir des processus d'extraction des métaux. Nous avons développé une nouvelle équation d'état (ÉÉ) basée sur une équation d'état du viriel comprenant un paramètre atypique tel que la température et la pression réduite pour la prédiction de la solubilité du soluté dans du dioxyde de carbone supercritique. Les données expérimentales de solubilité (solubilité du phosphate de tributyle dans CO2 SC) ont été corrélées avec les deux modèles d'équations d'état cubiques, soit l'ÉÉ Peng,Robinson (ÉÉ-PR) et l'ÉÉ Soave,Redlich,Kwong (ÉÉ-SRK), avec deux paramètres ajustables, les règles de mélange et de combinaison van der Waals et notre ÉÉ proposée. L'AARD de notre ÉÉ est significativement plus faible que celui obtenu à partir des autres modèles d'ÉÉ. L'ÉÉ proposée présentait une corrélation plus exacte pour les données de solubilité dans le CO2 SC. Elle peut être employée pour accélérer les processus des applications de FSC dans l'industrie. [source] Induction concurrent chemoradiotherapy compared with induction radiotherapy for superior sulcus non-small cell lung cancer: a retrospective studyASIA-PACIFIC JOURNAL OF CLINICAL ONCOLOGY, Issue 1 2010Jian LI Abstract Aim: To evaluate the efficacy of current chemoradiotherapy on improvement of survival in patients with superior sulcus non-small cell lung cancer (NSCLC). Methods: We retrospectively reviewed the data of 39 patients with superior sulcus NSCLC treated with induction therapy followed surgery. The patients were divided into two groups according to the induction approach: the induction radiotherapy (RT) group (1993,1999), and the induction chemoradiotherapy (CT/RT) group (since 1999). Results: The rate of complete resection was 65 percent in the RT group (n = 17) compared with 91 percent in the CT/RT group (n = 22, P = 0.024). Complete pathological responses from induction therapy were 12 percent in the RT group and 45 percent in the CT/RT group (P = 0.032). Overall survival (OS) was significantly longer in patients who received CT/RT than that in those who received RT, with 2- and 5-year survival rates of 77.3 percent and 36.4 percent versus 41.2 percent and 11.8 percent, respectively (P = 0.007). CT/RT also associated with a markedly longer tumor-free survival (TFS), with a median TFS of 40 and 17 months, respectively (P = 0.007). Patients achieved complete resection or complete pathological response had a significantly better survival than those with incomplete resection or pathological partial responses and no change (P < 0.0005 and P = 0.001, respectively). Conclusion: Our results indicate that CT/RT followed by surgery can significantly improve OS and TFS, and may be considered as an optimal option in treatment of patients with superior sulcus NSCLC. [source] The unidirectional glass fiber reinforced furfuryl alcohol for pultrusion.POLYMER COMPOSITES, Issue 6 2008The development of unidirectional glass fiber reinforced furfuryl alcohol (FA) composites has been conducted using an in situ polymerization method. The FA prepolymer synthesized in this study was prepared from blends of FA monomer and catalyst (p -toluene sulfonic acid). The process feasibility, and kinetic analysis of the unidirectional glass fiber reinforced FA composites by pultrusion has been investigated. From the investigations of the long pot life of FA prepolymer, the high reactivity of FA and FA/glass fiber, and excellent fiber wet-out of FA resin and glass fiber, it was found that the FA resin showed excellent process feasibility for pultrusion. A kinetic autocatalytic model, d,/dt = A exp(,E/RT),m(1,,)n, was proposed to describe the curing behavior of FA/glass fiber composites. Kinetic parameters for the model were obtained from dynamic differential scanning calorimetry scans using a multiple regression technique. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers [source] Influence of substrate temperature on the properties of electron beam evaporated ZnSe filmsCRYSTAL RESEARCH AND TECHNOLOGY, Issue 4 2010M. G. Syed Basheer Ahamed Abstract ZnSe films were deposited on glass substrates keeping the substrate temperatures, at room temperature (RT), 75, 150 and 250 °C. The films have exhibited cubic structure oriented along the (111) direction. Both the crystallinity and the grain size increased with increasing deposition temperature. A very high value of absorption co-efficient (104 cm -1) is observed. The band gap values decrease from a value of 2.94 eV to 2.69 eV with increasing substrate temperature. The average refractive index value is in the range of 2.39 , 2.41 for the films deposited at different substrate temperatures. The conductivity values increases continuously with temperature. Laser Raman spectra showed peaks at 140.8 cm -1, 246.7 cm -1and 204.5 cm -1which are attributable to 2TA LO phonon and TO phonon respectively. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Determination of lattice parameters and thermal expansion of CuGe2P3 + 0.2 Ge3P4 at elevated temperaturesCRYSTAL RESEARCH AND TECHNOLOGY, Issue 9 2006G. Bhikshamaiah Abstract CuGe2P3 is a p-type semiconductor with zincblende structure. Ge3P4 is soluble up to 35 mole% in CuGe2P3. Lattice parameters of CuGe2P3 + 0.2 Ge3P4 have been determined at elevated temperatures from room temperature to 873 K using the x-ray diffraction profiles (111), (200), (220), (311), (222), (400), (331), (420), (422) and (511) obtained from high temperature diffractometer. It is found that the lattice parameter increases linearly from 0.53856 nm at RT to 0.54025 nm at 873 K. The data on lattice parameter is used and coefficient of lattice thermal expansion of CuGe2P3 +0.2 Ge3P4 was determined at different temperatures. It is found that the coefficient of thermal expansion of CuGe2P3 +0.2 Ge3P4 is 5.48 x 10 -6 K -1 and is independent of temperature. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Personality disorders improve in patients treated for major depressionACTA PSYCHIATRICA SCANDINAVICA, Issue 3 2010R. T. Mulder Mulder RT, Joyce PR, Frampton CMA. Personality disorders improve in patients treated for major depression. Objective:, To examine the stability of personality disorders and their change in response to the treatment of major depression. Method:, 149 depressed out-patients taking part in a treatment study were systematically assessed for personality disorders at baseline and after 18 months of treatment using the SCID-II. Results:, Personality disorder diagnoses and symptoms demonstrated low-to-moderate stability (overall , = 0.41). In general, personality disorder diagnoses and symptoms significantly reduced over the 18 months of treatment. There was a trend for the patients who had a better response to treatment to lose more personality disorder symptoms, but even those who never recovered from their depression over the 18 months of treatment lost, on average, nearly three personality disorder symptoms. Conclusion:, Personality disorders are neither particularly stable nor treatment resistant. In depressed out-patients, personality disorder symptoms in general improve significantly even in patients whose response to their treatment for depressive symptoms is modest or poor. [source] Single-cell gene profiling of planarian stem cells using fluorescent activated cell sorting and its "index sorting" function for stem cell researchDEVELOPMENT GROWTH & DIFFERENTIATION, Issue 1 2010Tetsutaro Hayashi To achieve an integrated understanding of the stem cell system of planarians at both the cellular and molecular levels, we developed a new method by combining "fluorescent activated cell sorting (FACS) index sorting" analysis and single-cell reverse transcription,polymerase chain reaction (RT,PCR) to detect the gene expression and cell cycle state of stem cells simultaneously. Single cells were collected using FACS, and cDNAs of each cell were used for semi-quantitative RT,PCR. The results were plotted on the FACS sorting profile using the "index sorting" function, which enabled us to analyze the gene expression in combination with cell biological data (such as cell cycle phase) for each cell. Here we investigated the adult stem cells of planarians using this method and obtained findings suggesting that the stem cells might undergo commitment during S to G2/M phase. This method could be a powerful and straightforward tool for examining the stem cell biology of not only planarians but also other organisms, including vertebrates. [source] Eye remember you two: gaze direction modulates face recognition in a developmental studyDEVELOPMENTAL SCIENCE, Issue 5 2006Alastair D. Smith The effects of gaze direction on memory for faces were studied in children from three different age groups (6,7, 8,9, and 10,11 years old) using a computerized version of a task devised by Hood, Macrae, Cole-Davies and Dias (2003). Participants were presented with a sequence of faces in an encoding phase, and were then required to judge which faces they had previously encountered in a surprise two-alternative forced-choice recognition test. In one condition, stimulus eye gaze was either direct or deviated at the viewing phase, and eyes were closed at the test phase. In another condition, stimulus eyes were closed at the viewing phase, with either direct or deviated gaze at the test phase. Modulation of gaze direction affected hit rates, with participants demonstrating greater accuracy for direct gaze targets compared to deviated gaze targets in both conditions. Reaction times (RT) to correctly recognized stimuli were faster for direct gaze stimuli at the viewing phase, but not at the test phase. The age group of participants differentially affected these measures: there was a greater hit rate advantage for direct gaze stimuli in older children, although RTs were less affected by age. These findings suggest that while the facilitation of face recognition by gaze direction is robust across encoding and recognition stages, the efficiency of the process is affected by the stage at which gaze is modulated. [source] Assessment of different techniques for subcutaneous glucose monitoring in Type 1 diabetic patients during ,real-life' glucose excursionsDIABETIC MEDICINE, Issue 3 2010J. K. Mader Diabet. Med. 27, 332,338 (2010) Abstract Aims, To compare the accuracy of two marketed subcutaneous glucose monitoring devices (Guardian RT, GRT; GlucoDay S, GDS) and standard microdialysis (CMA60; MD) in Type 1 diabetic patients. Methods, Seven male Type diabetic patients were investigated over a period of 26 h simulating real-life meal glucose excursions. Catheters of the three systems were inserted into subcutaneous adipose tissue of the abdominal region. For MD, interstitial fluid was sampled at 30- to 60-min intervals for offline glucose determination. Reference samples were taken at 15- to 60-min intervals. All three systems were prospectively calibrated to reference. Median differences, median absolute relative differences (MARD), median absolute differences (MAD), Bland,Altman plot and Clark Error Grid were used to determine accuracy. Results, Bland,Altman analysis indicated a mean glucose difference (2 standard deviations) between reference and interstitial glucose of ,10.5 (41.8) % for GRT, 20.2 (55.9) % for GDS and 6.5 (35.2) % for MD, respectively. Overall MAD (interquartile range) was 1.07 (0.39; 2.04) mmol/l for GRT, 1.59 (0.54; 3.08) mmol/l for GDS and 0.76 (0.26; 1.58) mmol/l for MD. Overall MARD was 15.0 (5.6; 23.4) % (GRT), 19.7 (6.1; 37.6) % (GDS) and 8.7 (4.1; 18.3) % (MD), respectively. Total sensor failure occurred in two subjects using GRT and one subject using GDS. Conclusions, The three investigated technologies had comparable performance. Whereas GRT underestimated actual blood glucose, GDS and MD overestimated blood glucose. Considerable deviations during daily life meal glucose excursions from reference glucose were observed for all three investigated technologies. Present technologies may require further improvement until individual data can lead to direct and automated generation of therapeutic advice in diabetes management. [source] Measurement delay associated with the Guardian® RT continuous glucose monitoring systemDIABETIC MEDICINE, Issue 1 2010C. Wei Diabet. Med. Abstract Aims, Using compartment modelling, we assessed the time delay between blood glucose and sensor glucose measured by the Guardian® RT continuous glucose monitoring system in young subjects with Type 1 diabetes (T1D). Methods, Twelve children and adolescents with T1D treated by continuous subcutaneous insulin infusion (male/female 7/5; age 13.1 ± 4.2 years; body mass index 21.9 ± 4.3 kg/m2; mean ± sd) were studied over 19 h in a Clinical Research Facility. Guardian® RT was calibrated every 6 h and sensor glucose measured every 5 min. Reference blood glucose was measured every 15 min using a YSI 2300 STAT Plus Analyser. A population compartment model of sensor glucose,blood glucose kinetics was adopted to estimate the time delay, the calibration scale and the calibration shift. Results, The population median of the time delay was 15.8 (interquartile range 15.2, 16.5) min, which was corroborated by correlation analysis between blood glucose and 15-min delayed sensor glucose. The delay has a relatively low intersubject variability, with 95% of individuals predicted to have delays between 10.4 and 24.3 min. Population medians (interquartile range) for the scale and shift are 0.800 (0.777, 0.823) (unitless) and 1.66 (1.47, 1.84) mmol/l, respectively. Conclusions, In young subjects with T1D, the total time delay associated with the Guardian® RT system was approximately 15 min. This is twice that expected on physiological grounds, suggesting a 5- to 10-min delay because of data processing. Delays above 25 min are rarely to be observed. [source] Cognitive subprocesses and schizophrenia.ACTA PSYCHIATRICA SCANDINAVICA, Issue 2001Objective:,The aim of the study is to demonstrate that deficits of information processing in schizophrenic patients can be isolated with reaction-time (RT) decomposition paradigms. Method:,Three types of visually presented tasks were applied: simple, disjunctive and choice RT-tasks. RT were split into movement latency and time necessary to execute movements. Comparisons of three samples of schizophrenic patients (295.3) with individually matched (age, sex, education and handedness) healthy controls are presented: Sample 1: 10 drug-naive first-onset patients, Sample 2: 10 neuroleptically treated first-onset patients, Sample 3: 10 neuroleptically treated chronically ill patients. Results:,Findings indicate that schizophrenia affects primarily subprocesses in which percepts are translated into appropriate actions (response-selection). Neuroleptic treatment improves processing at this stage but is accompanied by slowing of movement execution. Conclusion:,Response-selection is selectively impaired in first-onset patients. This disturbance, which might be specific for schizophrenia, can be regarded as indication of a disconnection between frontal and posterior areas. [source] Positive impact of radiation dose on disease free survival and locoregional control in postoperative radiotherapy for squamous cell carcinoma of esophagusDISEASES OF THE ESOPHAGUS, Issue 4 2009S. Moon SUMMARY., The effect of total radiation dose (TRD) on the outcome of patients with postoperative radiotherapy (RT) for squamous cell carcinoma of esophagus was assessed. Sixty-seven patients with esophagectomy, followed by postoperative RT for squamous cell carcinoma of esophagus from June 1984 through February 2001, were retrospectively reviewed. Of these, 13 patients were excluded. No patient had chemotherapy. Patients were classified into two groups based on TRD delivered: TRD of less than 50 Gy (Group A, n = 16) and at least 50 Gy (Group B, n = 38). Follow-up duration of all patients ranged from 4 to 140 months (median, 14). Median TRD of Group A and B were 45 Gy (range, 45,48.6) and 54 Gy (range, 50,59.6), respectively. Median overall survival (OS) and disease-free survival (DFS) of all patients were 15 and 10 months, respectively. Although the TRD of 50 Gy or higher was marginally significant for improved OS (hazard ration [HR] 0.559, P = 0.066), it was statistically significant for improved DFS (HR 0.398, P = 0.011), and locoregional recurrence-free survival (HR 0.165, P = 0.001) with multivariate analysis. Three patients in group A and two in group B experienced a complication of grade 3 or higher. Our study suggests a positive impact of TRD of 50 Gy or higher on DFS and locoregional control, with acceptable morbidity in postoperative RT for patients with squamous cell carcinoma of esophagus. According to the present analysis, TRD should be at least 50 Gy in postoperative RT alone setting. [source] Preoperative chemoradiotherapy in cancer of the thoracic esophagusDISEASES OF THE ESOPHAGUS, Issue 1 2003G. Terrosu SUMMARY. Surgery with or without adjuvant radiotherapy (RT) is the standard treatment of esophageal cancer. Preoperative radio- and chemotherapy (CT) have been introduced to improve prognosis. We report a phase II prospective non-randomized trial of preoperative RT (42 Gy/25) plus CT (cisplatin 20 mg/mq/day plus 5-fluorouracil 600 mg/mq/day, 1,5 weeks) for the treatment of thoracic esophageal cancer. From 1993, 50 patients were enrolled (40 men and 10 women, mean age 57 years, range 30,75 years). Squamous cell carcinoma accounted for 90% of cases; 10% were adenocarcinoma. Downstaging of the disease was obtained in 77.3% of cases; there were 13 (29.5%) complete responses (CR) and 21 (47.7%) partial responses (PR). Median survival was 28 and 25 months, respectively, for CR and partial response (PR) plus stable disease (SD) and progressive disease (PD) (P = 0.05). Progressive-free median survival was 22 and 17 months, respectively, for CR and PR + SD + PD (P = 0.08). Multimodal treatment of esophageal cancer showed promising results, although not significant, in terms of survival and disease progression for patients achieving a complete pathologic response. [source] Evidence for implicit sequence learning in dyslexiaDYSLEXIA, Issue 1 2002Steve W. Kelly Abstract Nicolson and Fawcett (Cognition 1990; 35: 159,182) have suggested that a deficit in the automatization of skill learning could account for the general impairments found in dyslexia. Much of the evidence for their claims has been collected via a dual task paradigm, which might allow for alternative explanations of the data. The present study examines automatic skill learning in a single task paradigm and extends previous studies by independently examining the contribution of stimulus-based and response-based learning. The task replicates Mayr's (J. Exp. Psychol.: Learning Memory Cognition 1996; 22: 350,364) methodology in the Serial Reaction Time task by exposing participants to two structured displays, simultaneously. Learning is measured by comparing RT to the learned sequence against RT to a random display. This study demonstrates learning for both dyslexic and control groups for a spatial sequence which was observed and a concurrent non-spatial sequence which was responded to via a keypress. Learning of the sequence did not seem to depend on awareness of the sequence structure. These results suggest that automatic skill learning is intact in dyslexic individuals. Copyright © 2002 John Wiley & Sons, Ltd. [source] Measurement of Left Ventricular Ejection Fraction by Real Time 3D Echocardiography in Patients with Severe Systolic Dysfunction: Comparison with Radionuclide AngiographyECHOCARDIOGRAPHY, Issue 1 2010Hajo Müller M.D. Aim: Measurement of left ventricular ejection fraction (LVEF) using real time 3D echocardiography (3DE) has been performed in subjects with preserved or modestly reduced systolic function. Our aim was to evaluate this technique in the subset of patients with severe systolic dysfunction. Methods and results: Consecutive patients with LVEF less than 0.35 at two-dimensional echocardiography were included. LVEF obtained by 3DE was compared to the value measured by radionuclide angiography (RNA). Real time full-volume 3DE was performed, with offline semiautomated measurement of LVEF using dedicated software (Cardioview RT, Tomtec) by a single observer blinded to the results of RNA. A total of 50 patients were evaluated, of whom 38 (76%, 27 males, age 69 ± 13 years) had a 3DE of sufficient quality for analysis. LVEF for this group was 0.21 ± 0.07 using 3DE and 0.27 ± 0.08 using RNA. The agreement between the two techniques was rather poor (r = 0.49; P < 0.001; 95% limits of agreements of ,0.20 to 0.09). Truncation of the apex was observed in 6 of 38 (16%) patients. Conclusion: In patients with severe systolic dysfunction, 3DE shows poor agreement for measurement of LVEF as compared to RNA. There may be underestimation of up to 20% in absolute terms by 3DE. Accordingly, the two methods are not interchangeable for the follow-up of LV function. A limitation of 3DE may, at least in part, be related to the incomplete incorporation of the apical region into the pyramidal image sector in patients with dilated hearts. (Echocardiography 2010;27:58-63) [source] Effects of Continuous Positive Airway Pressure Therapy on Right Ventricular Function Assessment by Tissue Doppler Imaging in Patients with Obstructive Sleep Apnea SyndromeECHOCARDIOGRAPHY, Issue 10 2008Nihal Akar Bayram M.D. Objectives: The effects of continuous positive airway pressure (CPAP) therapy on right ventricular (RV) function in patients with obstructive sleep apnea syndrome (OSAS) has not been previously studied by tissue Doppler imaging (TDI). The aim of this study was to assess RV function using TDI in patients with OSAS before and after CPAP therapy. Methods: Twenty-eight patients with newly diagnosed OSAS in the absence of any confounding factors and 18 controls were included in this study. The peak systolic velocity (S,m), early (E,m) and late (A,m) diastolic myocardial peak velocities at tricuspid lateral annulus, isovolumic acceleration (IVA), myocardial precontraction time (PCT,m), myocardial contraction time (CT,m), and myocardial relaxation time (RT,m) were measured. All echocardiographic parameters were calculated 6 months after CPAP therapy. Results: The RV diastolic parameters such as E,m velocity and E,m-to-A,m ratio were significantly lower, RT,m was significantly prolonged, A,m velocity was similar in patients with OSAS compared to controls; and the RV systolic parameters such as IVA and CT,m were significantly lower and S,m was similar in patients with OSAS compared to controls. At the end of the treatment, 20 of 28 patients were compliant with CPAP therapy. E,m velocity, E,m-to-A,m ratio, IVA, and CT,m increased, PCT,m, PCT,m-to-CT,m ratio, and RT,m decreased significantly after therapy, whereas S,m velocity and A,m velocity did not change after CPAP treatment in the compliant patients. Conclusion: OSAS is associated with RV systolic and diastolic dysfunction, and 6 months of CPAP therapy improves the RV systolic and diastolic dysfunction. [source] Tagging effects on three non-native fish species in England (Lepomis gibbosus, Pseudorasbora parva, Sander lucioperca) and of native Salmo truttaECOLOGY OF FRESHWATER FISH, Issue 2 2009S. Stak Abstract,,, To address the dearth of information on tagging effects and long-term survivorship of tagged fish in native and introduced species, laboratory and field investigations were undertaken on three non-native fish species (pumpkinseed Lepomis gibbosus; topmouth gudgeon Pseudorasbora parva; pikeperch Sander lucioperca) tagged with coded-wire (CW), passive integrated transponder (PIT), radio (RT) telemetry and/or acoustic tags (AT), with survivorship of native brown trout (Salmo trutta) examined in the field. Laboratory results revealed high survivorship following tag attachment/insertion and resumption of feeding within 24,48 h of tagging (all mortalities could be attributed to an unrelated outbreak of fungal infection), with retention rates being high in both pumpkinseed and pikeperch but low in topmouth gudgeon (excluded from field studies). In the field, short-term post-operation survival was high in pikeperch, pumpkinseed and brown trout. In pumpkinseed and trout, 100% of RT fish survived a 24,30 day tracking study, with 60% and 80%, respectively, recaptured alive at least 3 months post-tagging. Of PIT tagged pumpkinseed, 44% were recaptured (after 6,18 months), with small-sized, CW-tagged fish (0.38 g weight) captured up to 1 year after tagging. In pikeperch, all AT fish except one (the smallest specimen) survived their full expected tracking period (i.e. tag life) , the single lost specimen survived at least half of its expected tracking period (i.e. 6 month battery life). Overall, the tagging methods used were highly effective in pumpkinseed and pikeperch, showing good retention and survival, but PIT tagging of topmouth gudgeon was plagued by low survivorship and tag rejection. [source] The effect of image complexity on attentional bias towards alcohol-related images in adult drinkersADDICTION, Issue 5 2010Melissa A. Miller ABSTRACT Aim Visual probe tasks are often used to measure attentional bias (AB) towards alcohol-related images in drinkers, but little is known about the effect of the properties of the images used in this task: specifically, image complexity. Methods AB was examined in a group of adult drinkers (n = 25). Two measures of attentional bias were obtained from a modified visual probe task. First, a traditional dot probe detection task measured attentional bias in drinkers based on their reaction times to probes replacing neutral and alcohol-related images. Secondly, an eye-tracking measure was applied to this task to directly assess the drinkers' eye gazes to the alcohol-related and neutral images. The effect of image complexity was examined by comparing AB towards images classified as simple and complex. Findings Results showed that drinkers displayed AB only towards simple alcohol-related images as measured by both probe RT and fixation times. Conclusion These findings suggest that complex alcohol-related images might be less effective at capturing drinkers' attention and could result in less attentional bias when used in visual probe tasks. [source] Development of 230,270 nm AlGaN-based deep-UV LEDsELECTRONICS & COMMUNICATIONS IN JAPAN, Issue 3 2010Hideki Hirayama Abstract We demonstrated AlGaN multi-quantum well (MQW) deep-ultraviolet (UV) light-emitting diodes (LEDs) with wavelengths in the range of 227.5 to 273 nm fabricated on high-quality AlN buffers on sapphire substrates grown by metal-organic chemical vapor deposition (MOCVD). We realized crack-free, thick AlN buffers on sapphire with a low threading dislocation density (TDD) and an atomically flat surface by using the ammonia (NH3) pulse-flow multilayer (ML) growth technique. We obtained single-peaked operation of an AlGaN-MQW LED with a wavelength of 227.5 nm, which is the shortest wavelength of AlGaN-based LED on sapphire. The maximum output power and the external quantum efficiency (EQE) of the 261- and 227.5-nm LEDs were 1.65 mW and 0.23% in room-temperature (RT) continuous-wave (CW) operation, and 0.15 mW and 0.2% in RT pulsed operation, respectively. © 2010 Wiley Periodicals, Inc. Electron Comm Jpn, 93(3): 24,33, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10197 [source] Study of binding stoichiometries of the human immunodeficiency virus type,1 reverse transcriptase by capillary electrophoresis and laser-induced fluorescence polarization using aptamers as probesELECTROPHORESIS, Issue 2 2006Hao Fu Abstract Binding stoichiometries between four DNA aptamers (RT12, RT26, RTlt49, and ODN93) and the reverse transcriptase (RT) of the type,1 human immunodeficiency virus (HIV-1) were studied using affinity CE (ACE) coupled with LIF polarization and fluorescence polarization (FP). The ACE/LIF study showed evidence of two binding stoichiometries between the HIV-1,RT protein and aptamers RT12, RT26, and ODN93, suggesting that these aptamers can bind to both the p66 and p51 subunits of the HIV-1,RT. Only one binding stoichiometry for aptamer RTlt49 was found. The affinity complexes were easily separated from the unbound aptamers; however, the different stoichiometries were not well resolved. A complementary technique, FP, was able to provide additional information about the binding and supporting evidence for the ACE/LIF results. The ACE/LIFP study also revealed that the FP values of the 1:1 complexes of the HIV-1,RT protein with aptamers RT12, RT26, and ODN93 were always much greater than those of the 1:2 complexes. This was initially surprising because the larger molecular size of the 1:2 complexes was expected to result in higher FP values than the corresponding 1:1 complexes. This phenomenon was probably a result of fluorescence resonance energy transfer between the two fluorescent molecules bound to the HIV-1,RT protein. [source] Human enteric viruses in groundwater indicate offshore transport of human sewage to coral reefs of the Upper Florida KeysENVIRONMENTAL MICROBIOLOGY, Issue 4 2010J. Carrie Futch Summary To address the issue of human sewage reaching corals along the main reef of the Florida Keys, samples were collected from surface water, groundwater and coral [surface mucopolysaccharide layers (SML)] along a 10 km transect near Key Largo, FL. Samples were collected semi-annually between July 2003 and September 2005 and processed for faecal indicator bacteria (faecal coliform bacteria, enterococci and Clostridium perfringens) and human-specific enteric viruses (enterovirus RNA and adenovirus DNA) by (RT)-nested polymerase chain reaction. Faecal indicator bacteria concentrations were generally higher nearshore and in the coral SML. Enteric viruses were evenly distributed across the transect stations. Adenoviruses were detected in 37 of 75 samples collected (49.3%) whereas enteroviruses were only found in 8 of 75 samples (10.7%). Both viruses were detected twice as frequently in coral compared with surface water or groundwater. Offshore, viruses were most likely to be found in groundwater, especially during the wet summer season. These data suggest that polluted groundwater may be moving to the outer reef environment in the Florida Keys. [source] | |||||||||||||||||||||||||||||||||||||||||||||||||