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Index Test (index + test)
Selected AbstractsDetection of Mild Hyposalivation in Elderly People Based on the Chewing Time of Specifically Designed Disc Tests: Diagnostic AccuracyJOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 4 2009DrOdont, Isabelle Madinier DDS OBJECTIVES: To compare sialometry with chewing time (including swallowing) of specifically designed disc tests. DESIGN: Index test versus reference standard (sialometry; 60 patients); reliability study (10 patients). SETTING: Outpatient dental clinic and geriatric ward, Nice University Hospital, France. PARTICIPANTS: Thirty adults and 30 older patients (mean ages 47 and 84). INTERVENTION: Index test assessment in patients with and without hyposalivation. MEASUREMENTS: Data from medical files, interviews and oral examination were collected. Sialometry (stimulated salivary flow rate (SSFR) mL/min) and disc chewing times (seconds) were measured. RESULTS: Sialometry was too long and was inappropriate for five of the 30 older persons. Chewing times were negatively correlated to sialometry results (Spearman correlation coefficient (R)=0.77, P<.001). The threshold to diagnose hyposalivation (SSFR <1 mL/min) was 40 seconds (area under the receiver operating characteristic curve (AUC)=0.921, 100% sensitivity, 72% specificity). Twenty-seven subjects with a SSFR less than 1.5 mL/min had a chewing time longer than 40 seconds, suggesting that mild hyposalivation and eating difficulties were related (AUC=0.941, 93% sensitivity, 88% specificity). Mean chewing time was greater with xerostomia (51.9 vs 30.7 seconds, P<.001) but not with dental pain (39.5 vs 39.9, P=.96). Masticatory percentage (e.g., pairs of antagonistic teeth) had no effect on chewing time (SSFR <1 mL/min, AUC=0.921; SSFR <1.5 mL/min, AUC=0.950). Reliability was better for the disc test than for sialometry (intraclass correlation 0.85 vs 0.70). CONCLUSION: This disc test was conceived to detect mild hyposalivation in geriatric patients with impaired dental health. Early detection of hyposalivation could help to suppress or avoid xerostomia-inducing drugs and to prevent oral infections and dental caries. [source] A novel route for preparation of PVC sheets with high UV irradiation resistanceJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2010Xianke Ye Abstract A novel acrylonitrile acrylate copolymer coating was proposed to improve the UV irradiation resistance of poly(vinyl chloride) (PVC) sheets. Its effect on the photoageing properties of the sheets was evaluated by means of Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), yellowness index test, and the oxygen permeability coefficient and mechanical properties measurement. The experimental results show that the novel acrylonitrile acrylate copolymer coating significantly improves the UV irradiation resistance of PVC sheets. Compared with the PVC sheets without coating, the coated PVC sheets show better mechanical properties, lower yellowness index, and smaller oxygen permeability coefficient after UV irradiation. The analysis on the SEM images of the PVC sheets indicates that the coating acts as a film to prevent the PVC sheets from UV energy and oxygen that can accelerate the photochemical reactions of PVC. The FTIR analysis confirms that the coating can slow down the microstructures development of the PVC sheets, also indicating that the coating impeded the photochemical reactions of PVC. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Thermal behavior and flame retardancy of flexible poly(vinyl chloride) treated with zinc hydroxystannate and zinc stannateJOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 1 2008Weihong Wu The flame-retardant and smoke-suppressant properties of inorganic tin compounds such as zinc hydroxystannate (ZHS) and zinc stannate (ZS) were studied in comparison with those of alumina trihydrate and magnesium hydroxide through the limiting oxygen index test and a smoke density test. The thermal degradation in air of flexible poly(vinyl chloride) (PVC) treated with the above compounds was studied by thermal analysis from ambient temperature to 800°C. The activation energy was calculated by using the Vyazovkin model-free kinetic method and the Kissinger method. The results showed that tin compounds such as ZHS and ZS could be used as highly effective flame retardants for flexible PVC; these flame retardants enhanced the stability and the activation energy of the oxidation of the char. J. VINYL ADDIT. TECHNOL, 2008. © 2008 Society of Plastics Engineers [source] Is home spirometry useful in diagnosing asthma in children with nonspecific respiratory symptoms?,PEDIATRIC PULMONOLOGY, Issue 4 2010Alwin F.J. Brouwer MD Abstract Background Variation of lung function is considered to be a hallmark of asthma. Although guidelines recommend measuring it as a diagnostic tool for asthma, the usefulness of this approach has not been studied in children. Aim To assess the usefulness of home spirometry in children with nonspecific lower respiratory tract symptoms, to diagnose or exclude asthma. Methods In school-aged children, referred by their general practitioner because of chronic respiratory symptoms of unknown origin, the diagnosis of asthma was made or excluded by a pediatric pulmonologist (gold standard), based on international guidelines and a standardized protocol. Additionally, children measured peak expiratory flow (PEF) and forced expiratory flow in 1,sec (FEV1) twice daily for 2 weeks on a home spirometer, from which diurnal variation was calculated. These results (index test) were not revealed to the pediatric pulmonologist. The value of home spirometry to diagnose asthma was calculated. Results Sixty-one children (27 boys) were included (mean age: 10.4 years; range: 6,16 years). Between asthma and no asthma, the mean difference in PEF variation was 4.4% (95% CI: 0.9,7.9; P,=,0.016) and in FEV1 variation 4.5% (95% CI: 1.6,7.4; P,=,0.003). Sensitivity and specificity, based on the 95th-centile of the reference values for PEF and FEV1 variation (12.3% and 11.8%, respectively) were 50% and 72% for PEF variation and 45% and 92% for FEV1 variation. The likelihood ratio was 1.8 for PEF and 5.6 for FEV1. Conclusions The contribution of home spirometry in the diagnostic process for asthma in schoolchildren with nonspecific respiratory symptoms is limited. Pediatr Pulmonol. 2010; 45:326,332. © 2010 Wiley-Liss, Inc. [source] On-line adaptive metabolic flux analysis: Application to PHB production by mixed microbial culturesBIOTECHNOLOGY PROGRESS, Issue 2 2009João Dias Abstract In this work, an algorithm for on-line adaptive metabolic flux analysis (MFA) is proposed and applied to polyhydroxybutyrate (PHB) production by mixed microbial cultures (MMC). In this process, population dynamics constitutes an important source of perturbation to MFA calculations because some stoichiometric and energetic parameters of the underlying metabolic network are continuously changing over time. The proposed algorithm is based on the application of the observer-based estimator (OBE) to the central MFA equation, whereby the role of the OBE is to force the accumulation of intracellular metabolites to converge to zero by adjusting the values of unknown network parameters. The algorithm was implemented in a reactor equipped with on-line analyses of dissolved oxygen and carbon dioxide through respirometric and titrimetric measurements. The oxygen and carbon dioxide fluxes were measured directly, whereas acetate, PHB, and sludge production fluxes were estimated indirectly using a projection of latent structures model calibrated a priori with off-line measurements. The algorithm was implemented in a way that the network parameters associated with biosynthesis were adjusted on-line. The algorithm proofed to converge exponentially with the steady state error always below 1 mmol/L. The estimated fluxes passed the consistency index test for experimental error variances as low as 1%. The comparison of measured and estimated respiratory coefficient and of the theoretical and estimated yield of sludge on acetate further confirmed the metabolic consistency of the parameters that were estimated on-line. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009 [source] The Influence of the Parameter "Temperature" on the Abrasiveness of RockGEOMECHANICS AND TUNNELLING, Issue 1 2008Stefan Eberl cand.rer.mont. The article deals with the influence of temperature produced in the cutting process on rock abrasiveness and tool wear. Basically it was to clarify which effects take place when quartz or rock with significant quartz content is heated up to a certain temperature. Does the quartz jump from low into high quartz happening at 573 °C cause an increase in abrasiveness of mineral and rock or not? To find out, a certain number of Cerchar abrasiveness index tests were done for a detailed investigation of this topic. Additionally, to get a better understanding what really happens inside rock structure additionally other rock parameters like unconfined compressive strength, Brazilian tensile strength, ultrasonic wave velocity and density were determined on untreated and heated and subsequently cooled down rock samples. The final output of the research work showed that rocks show a very specific and significant reaction to thermal stresses induced into their structure resulting in a different behaviour regarding abrasiveness and fracturing. Einfluss des Parameters "Temperatur" auf die Abrasivität von Fels Der Artikel beschäftigt sich mit dem Einfluss der während des Schneidprozesses entstehenden Temperatur auf die Abrasivität von Gestein und auf den Verschleiß des Schneidwerkzeugs. Es sollte geklärt werden, welche Effekte auftreten, wenn Quarz und Gestein mit erheblichem Quarzgehalt bis zu einer bestimmten Temperatur erhitzt werden. Erzeugt der Quarzsprung, der bei 573 °C stattfindet, von Tiefquarz zu Hochquarz einen Anstieg in der Abrasivität von Mineralen und Gesteinen oder nicht? Um dies herauszufinden, sind eine bestimmte Anzahl von Cerchar Abrasivitätstests durchgeführt worden. Um ein besseres Verständnis zu erhalten, was wirklich in der Struktur des Gesteins passiert, sind weitere Parameter wie einachsiale Druckfestigkeit, Spaltzugfestigkeit, Ultraschallwellengeschwindigkeit und Dichte an unbehandelten und aufgeheizten und wieder abgekühlten Gesteinsproben bestimmt worden. Die Forschungsarbeit hat gezeigt, dass Gesteine eine sehr spezifische und signifikante Reaktion auf thermische Beanspruchungen ihres Gefüges zeigen, was letztlich in einem verschiedenartigen Verhalten hinsichtlich Abrasivität und Bruchverhalten zum Ausdruck kommt. [source] Preparation of poly(acrylonitrile,butadiene,styrene)/montmorillonite nanocomposites and degradation studies during extrusion reprocessingJOURNAL OF APPLIED POLYMER SCIENCE, Issue 4 2009E.-K. Karahaliou Abstract In this study, the preparation of organically modified montmorillonite/poly(acrylonitrile,butadiene,styrene) (ABS) nanocomposites was studied by melt blending in a twin-screw extruder. The composite material was subjected to a series of five extrusion cycles, and the effect of reprocessing on the material's structural properties was investigated. More specifically, chemical changes were studied with attenuated total reflectance/Fourier transform infrared analysis, the thermal response was recorded by differential scanning calorimetry experiments, and the thermal stability was detected with thermogravimetric analysis. Also, the rheological properties of these blends were investigated via melt flow index tests as a measure of their processability during melt mixing and molding processes. Furthermore, the mechanical strength of the obtained mixtures was explored, and the observed interactions were interpreted in terms of the influence of each component on the functional properties of the final mixture. This attempt enriched our knowledge about the recycling of ABS, with the additional aspect of the use of collected data from more complex systems, that is, composite materials, where the montmorillonite nanoparticles play a role in the interactions initiated by repeated processing. The experimental results of this study show that the reprocessing of ABS/montmorillonite induced oxidation products, but the rheological, mechanical, and thermal properties and the thermal and color stabilities of the composites remained almost stable. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 [source] | |||||||||||||