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Test Materials (test + material)
Selected AbstractsLight (minimal) pruning enhances expression of higher yield from clones of Vitis vinifera L. cv. Sultana following thermotherapy for virus attenuationAUSTRALIAN JOURNAL OF GRAPE AND WINE RESEARCH, Issue 2 2002PETER R. CLINGELEFFER Abstract High-yielding clones of Sultana (syn. Thompson Seedless) were grown in a warm climate under irrigation as either cane-pruned or minimally-pruned field vines. Test material included Sultana clone H5, six heat-treated clones originating from H5, and a heat-treated clone of Thompson Seedless (TS-HT91) sourced from California. Vine performance was measured over 10 seasons (1984,1993). Previous thermotherapy had eliminated leafroll viruses from three of the six selections originating from H5 and from TS-HT91. When cane-pruned, the TS-HT91 clone was 9% more productive than H5 as well as all selections originating from thermotherapy of H5. With minimal pruning all selections free of leafroll viruses had superior performance (approximately 14% increase) compared to those still infected with leafroll viruses. In those clones where thermotherapy had not removed leafroll viruses, yields from two out of three clones (minimally-pruned) were increased relative to H5; one remained lower. Clonal differences in productivity were related to vine growth, particularly above-ground components, but there were no significant clonal effects on berry weight, pH or titratable acidity. While long-term field trials are necessary to clearly demonstrate positive effects from thermotherapy, light pruning can enhance prospects for confirming an improvement in yield. Indeed, severe pruning can even limit expression of yield from putatively superior clones, and thus mask expression of positive outcomes from thermotherapy. [source] Formaldehyde-releasers: relationship to formaldehyde contact allergy.CONTACT DERMATITIS, Issue 1 2010Part 2. This is the second part of a review article on formaldehyde-releasers used as durable press chemical finishes (DPCF) in textiles. The early finishes contained large amounts of free formaldehyde, which led to many cases of allergic contact dermatitis to clothes in the 1950s and 1960s. Currently, most finishes are based on modified dimethylol dihydroxyethyleneurea, which releases less formaldehyde. Nevertheless, recent studies in the United States and Israel have identified patients reacting to DPCF, considered to have allergic contact reactions to clothes, either from formaldehyde released by the DPCF therein or from the DPCF per se (in patients negative to formaldehyde). However, all studies had some weaknesses in design or interpretation and in not a single case has the clinical relevance been proven. The amount of free formaldehyde in most garments will likely be below the threshold for the elicitation of dermatitis for all but the most sensitive patients. The amount of free cyclized urea DPCF in clothes is unlikely to be high enough to cause sensitization. Patch test reactions to formaldehyde-releasing DPCF will in most cases represent a reaction to formaldehyde released from the test material. [source] Survey of Theoretical Work for the Proposed HEDgeHOB Experimental Schemes: HIHEX and LAPLASCONTRIBUTIONS TO PLASMA PHYSICS, Issue 4-5 2007N. A. Tahir Abstract This paper presents a review of the theoretical work that has resulted in a scientific proposal on studies of High-Energy-Density (HED) states in matter using intense beams of energetic heavy ions that will be available at the future Facility for Antiprotons and Ion Research (FAIR) at Darmstadt [W.F. Henning, Nucl. Inst. Meth B 24 (2003) 725-729]. The proposal is named HEDgeHOB that stands for High Energy Density Matter Generated by Heavy Ion Beams. Two experimental schemes have been worked out for the HEDgeHOB experimental proposal, namely, HIHEX and LAPLAS. The first scheme allows for studies of HED states by isochoric and uniform heating of matter by an intense heavy ion beam that is followed by isentropic expansion of the heated material. Numerical simulations have shown that using the beam parameters that will be available at the FAIR, one can access all the interesting physical states of HED matter including an expanded hot liquid state, twophase liquid-gas region, critical point parameters and strongly coupled plasmas for all the materials of interest. The second scheme involves a low-entropy compression of a test material like hydrogen that is enclosed in a cylindrical shell of a high-Z material like gold or lead. The target can be driven by a hollow or a circular beam. This compression scheme relies on multiple shock reflection between the hydrogen-gold (lead) boundary and the cylinder axis. The hydrodynamic stability of the LAPLAS target has also been analyzed that shows that the implosion is completely stable to Rayleigh-Taylor and Richtmyer-Meshkov instabilities. LAPLAS implosion using a hollow beam is suitable for studying the problem of hydrogen metallization whereas the one employing a circular focal spot leads to physical conditions that are expected to exist in the interiors of the giant planets. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Physiological and biochemical analyses of microcystin-RR toxicity to the cyanobacterium Synechococcus elongatusENVIRONMENTAL TOXICOLOGY, Issue 6 2004Zhi-quan Hu Abstract Freshwater Microcystis may form dense blooms in eutrophic lakes. It is known to produce a family of related cyclic hepatopeptides (microcystins, MC) that constitute a threat to aquatic ecosystems. Most toxicological studies of microcystins have focused on aquatic animals and plants, with few examining the possible effects of microcystins on phytoplankton. In this study we chose the unicellular Synechococcus elongatus (one of the most studied and geographically most widely distributed cyanobacteria in the picoplankton) as the test material and investigated the biological parameters: growth, pigment (chlorophyll-a, phycocyanin), photosynthetic activity, nitrate reductase activity, and protein and carbohydrate content. The results revealed that microcystin-RR concentrations above 100 ,g · L,1 significantly inhibited the growth of Synechococcus elongatus. In addition, a change in color of the toxin-treated algae (chlorosis) was observed in the experiments. Furthermore, MC-RR markedly inhibited the synthesis of the pigments chlorophyll-a and phycocyanin. A drastic reduction in photochemical efficiency of PSII (Fv/Fm) was found after a 96-h incubation. Changes in protein and carbohydrate concentrations and in nitrate reductase activity also were observed during the exposure period. This study aimed to evaluate the mechanisms of microcystin toxicity on a cyanobacterium, according to the physiological and biochemical responses of Synechococcus elongatus to different doses of microcystin-RR. The ecological role of microcystins as an allelopathic substance also is discussed in the article. © 2004 Wiley Periodicals, Inc. Environ Toxicol 19: 571,577, 2004. [source] An investigation of liquid film thickness during solutal Marangoni condensation using a laser absorption method: Absorption property and examination of measuring methodHEAT TRANSFER - ASIAN RESEARCH (FORMERLY HEAT TRANSFER-JAPANESE RESEARCH), Issue 8 2003Yoshio Utaka Abstract The objective of the study is to establish a method for measuring the thickness of thin condensates of liquid mixtures using a laser light absorption method during the process of water,ethanol Marangoni dropwise condensation. First, the extinction property of the test material, with unknown properties related to infrared laser light having a wavelength of 3.39µm, was measured. Next, measurements were made of the variations in condensate film thickness after the sweeping of the heat transfer surface by departing drops in the Marangoni dropwise condensation cycle. The precision of this method was investigated on the basis of the extinction coefficient of the test material and the thickness of the liquid film. Results showed that this method provides good precision and is applicable to the measurement of other similar materials. © 2003 Wiley Periodicals, Inc. Heat Trans Asian Res, 32(8): 700,711, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.10124 [source] Polymer characterization by ultrasonic wave propagationADVANCES IN POLYMER TECHNOLOGY, Issue 2 2008Francesca Lionetto Abstract The propagation of low-intensity ultrasound in polymers, acting as a high-frequency dynamic mechanical deformation, can be successfully used to monitor changes in the modulus of polymers associated with glass transition, crystallization, cross-linking, and other chemical and physical phenomena related to changes in the viscoelastic behavior, such as gelation phenomena. The velocity of sound is related to the polymer storage modulus and density, whereas the absorption of ultrasonic waves is related to the energy dissipation in the material and, therefore, to the loss modulus. Accordingly, ultrasonic measurements have been used by several authors to monitor the evolution of the viscoelastic moduli of polymers as a function of time or temperature and, recently, become a characterization technique of its own right, generally known as ultrasonic dynamic mechanical analysis (UDMA). Often the technique is used in conjunction with rheological methods as a means of providing a better insight into the viscoelastic behavior of polymer systems. As yet UDMA is underutilized primarily because of the low operating temperatures (usually below 100,C) of commercially available ultrasonic transducers, and also due to the requirement of a coupling medium to ensure an efficient energy transfer mechanism between the transducer and the test material. Despite these limitations, this paper shows that the use of ultrasonics is potentially a powerful method for the characterization of polymers, particularly as a tool for online monitoring of events occurring during polymer processing and in the manufacture of polymer matrix composites. The aim of this paper is to review the progress made in recent years, highlighting the potential and reliability of UDMA for monitoring physical transitions in polymers such as glass transition, melting, crystallization, as well as physical changes taking place during curing of thermosetting resins. © 2009 Wiley Periodicals, Inc. Adv Polym Techn 27:63,73, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20124 [source] INFLUENCE OF MEASUREMENT TECHNIQUE, TEST FOOD, TEETH AND MUSCLE FORCE INTERACTIONS IN MASTICATORY PERFORMANCEJOURNAL OF TEXTURE STUDIES, Issue 1 2007FLÁVIA RIQUETO GAMBARELI ABSTRACT The role of texture and flavors in mastication is evident, but it is difficult to understand the interactions among food properties, oral physiology and perception. Mastication results from rhythmic mandibular movements. The teeth and masticatory muscles together form the mechanism whereby the food particles are fragmented. Masticatory performance and efficiency are defined as the capacity to reduce natural or artificial test materials during mastication, or by counting the number of strokes required to reduce food, respectively. Foods eaten for nourishment are very different from the industrial test materials used to quantify masticatory performance, thus, divergences could arise if the chewable material can or cannot be swallowed. This study presents a synopsis of masticatory performance methods, which is also related to muscle force, number of teeth and test chewing substance diversity. PRACTICAL APPLICATIONS The attributes of food, such as appearance, flavor and texture, as well as its interaction with saliva, number of teeth and conditions of the biomechanical system, influence the chewing process. In addition, reflex control and cognition can influence food perception and breakdown in the mouth. Food acceptability and choice depend on sensory properties of the food, which are perceived during chewing and swallowing. Masticatory performance and maximal occlusal force measurement may provide essential information that could lead to an appropriate diagnosis as regards masticatory function. Masticatory efficiency and performance can be measured to determine the individual's capacity to comminute a natural or a chewable test material. A material with uniform properties that can be reliably reproduced is essential to provide an ideal test bolus for the scientific study of masticatory effectiveness. [source] CHARACTERIZATION OF THE NONLINEAR VISCOELASTIC CONSTITUTIVE PROPERTIES OF MILD CHEDDAR CHEESE FROM INDENTATION TESTSJOURNAL OF TEXTURE STUDIES, Issue 5-6 2005S.M. GOH ABSTRACT A methodology to convert the indentation force,displacement response into the stress,strain properties of nonlinear viscoelastic materials was evaluated. Mild cheddar cheese was used as the test material, and indentation tests were performed using two spherical indenters of different sizes. The indentation tests were performed at different speeds, and the corresponding force,displacement responses were fitted with an analytical solution to obtain the time-dependent constants and the instantaneous force,displacement response. An inverse analysis based on the finite element method was performed to obtain the strain-dependent constants from the instantaneous force,displacement response. The predictions of the viscoelastic stress,strain properties from the indentation tests were compared to independent measurements through uniaxial compression tests, and a reasonable agreement was obtained. [source] Effect of mating surface on the high temperature wear of 253 MA alloyMATERIALS AND CORROSION/WERKSTOFFE UND KORROSION, Issue 4 2004M. Roy Abstract The wear behaviour of metallic material is influenced by the friction force, which in turn, is governed by the hardness and oxidation kinetics of the mating surface. In view of this, present investigation is undertaken to find the influence of mating surface on the high temperature wear of 253 MA alloy. This alloy is developed for high temperature application. In this work 253 MA alloy is made to slide against two different types of counter face material, namely 100Cr6 steel and PM 1000 alloy, at five different temperatures. 100Cr6 steel gets soften with increase of temperature whereas PM 1000 alloy retains its strength even at high temperature. The friction coefficient and the thickness loss of 253 MA alloy is measured and compared against both variety of mating surfaces as function of temperatures. The morphology of the worn surfaces and the transverse section of the worn surfaces are examined under scanning electron microscope (SEM) to identify the material removal mechanisms. The results showed that the friction coefficient of test material against PM 1000 alloy is around 40% higher than the friction coefficient against 100Cr6 steel. The transverse section of the worn surface showed presence of a transfer layer, mechanically mixed layer and composite layer, which govern the wear behaviour particularly at elevated temperature. The chemical characteristics of these layers are dependent on the test temperature and the counter face material. [source] Effectiveness of dentine bonding agents against cariogenic bacteria in vitro: a comparison of two methodsMOLECULAR ORAL MICROBIOLOGY, Issue 3 2003O. A. Schmidlin Data obtained from studies on the antimicrobial properties of bonding agents are the subject of controversy, probably because of methodological differences. This study compared two commonly used in vitro methods, the disc agar diffusion test and the well agar diffusion test. Agar plates were seeded with Streptococcus sobrinus, Lactobacillus gasseri, or Actinomyces naeslundii. For the well diffusion test, wells cut out of the agar were filled with the test material, and for the disc method, discs impregnated with the test material were applied to the agar; the discs and wells were both 9 mm in diameter. After incubation, measurements of the zones of inhibition showed little agreement between the two methods when bonding agents were tested; the mean differences (± sdiff) in the zones of inhibition between the methods were 0.7 ± 3.4 mm (P = 0.40, one sample t -test against zero), 4.9 ± 4.4 mm (P = 0.97), and 0.8 ± 4.3 mm (P = 0.47) for S. sobrinus, L. gasseri, and A. naeslundii, respectively. Mean differences were less contrasting when chlorhexidine and pure components were tested (P < 0.05 for S. sobrinus and L. gasseri). These results indicate the need for a gold standard method to evaluate the antimicrobial properties of bonding agents. [source] A SELDI-TOF MS procedure for the detection, quantitation, and preliminary characterization of low-molecular-weight recombinant proteins expressed in transgenic plantsPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 2 2009M. Amine Badri Abstract We describe a SELDI-TOF MS procedure for the rapid detection and quantitation of low-molecular-weight recombinant proteins expressed in plants. Transgenic lines of potato (Solanum tuberosum L.) expressing the clinically useful protein bovine aprotinin or the cysteine protease inhibitor corn cystatin II were generated by Agrobacterium tumefaciens -mediated transformation, and then used as test material for the analyses. Real-time RT-PCR amplifications and detection of the recombinant proteins by immunoblotting were first conducted for transformed potato lines accumulating the proteins in different cell compartments. Both proteins were found at varying levels in leaves, depending on their final cellular destination and transgene expression rate. These conclusions drawn from standard immunodetection assays were easily confirmed by SELDI-TOF MS comparative profiling, after immobilizing the leaf proteins of control and transformed lines on protein biochips for weak cationic exchange. This procedure, carried out in less than 2,h, allows for the rapid comparison of recombinant protein levels in transgenic plant lines. The molecular weight of immobilized proteins can also be determined directly from the MS spectra, thus providing a simple way to assess the structural integrity and homogeneity of recombinant proteins in planta, and to identify the most suitable cellular compartments for their heterologous production. [source] The utility of ultra-performance liquid chromatography/electrospray ionisation time-of-flight mass spectrometry for multi-residue determination of pesticides in strawberryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 17 2008Michael J. Taylor The utility of ultra-performance liquid chromatography/orthogonal-acceleration time-of flight mass spectrometry (UPLC/TOFMS) for the rapid qualitative and quantitative analysis of 100 pesticides targeted in strawberry was assessed by comparing results with those obtained using a validated in-house UPLC tandem mass spectrometry (MS/MS) multi-residue method. Crude extracts from retail strawberry samples received as part of the 2007 annual UK pesticide residues in food surveillance programme were screened for the presence of pesticide residues using UPLC/TOFMS. Accurate mass measurement of positive and negative ions allowed their extraction following ,full mass range data acquisition' with negligible interference from background or co-eluting species observed during UPLC gradient separation (in a cycle time of just 6.5,min per run). Extracted ion data was used to construct calibration curves and to detect and identify any incurred residues (i.e. pesticides incorporated in or on the test material following application during cultivation, harvest and storage). Calibration using matrix-matched standards was performed over a narrow concentration range of 0.005,0.04,mg,kg,1 with determination coefficients (r2) ,0.99 for all analytes with the exception of malathion/fenarimol/fludioxanil (r2,=,0.98), quassia/pymetrazine (r2,=,0.97) and fenthion sulfone (r2,=,0.95). Residues found in selected samples ranged from 0.025,0.28,mg,kg,1 and were in excellent agreement with results obtained using UPLC/MS/MS. Mass measurement accuracies of ,5,ppm were achieved consistently throughout the separation, mass range and concentration range of interest thus providing the opportunity to obtain discrete elemental compositions of target ions. © Crown copyright 2008. Reproduced with the permission of Her Majesty's Stationery Office. Published by John Wiley & Sons, Ltd. [source] Life-cycle toxicity of dibutyltin to the sheepshead minnow (Cyprinodon variegatus) and implications of the ubiquitous tributyltin impurity in test materialAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 9 2003Thomas F. Lytle Abstract Dibutyltin (DBT) is used in the plastics polymerization process as a catalyst in polyvinyl chloride (PVC) products and is the primary degradation product of tributyltin (TBT), an antifoulant in marine paint. DBT and other organotin compounds make their way into the environment through antifoulants, PVC processing plants, and PVC products maintained in water and water-handling systems. A flow-through saltwater life-cycle toxicity test was conducted to determine the chronic effect of DBT to the sheepshead minnow (Cyprinodon variegatus Lacepede), an estuarine species. Embryos were monitored through hatch, maturation, growth, and reproduction in DBT concentrations of 158, 286, 453, 887, and 1510 µg l,1. Progeny were monitored for survival as embryos and fry/juveniles, and growth for 30 days post-isolation. Mean length of parental generation fish was significantly reduced on day 30 at DBT concentrations ,887 µg l,1, setting the lowest observable effect concentration (LOEC) at 887 µg l,1 and the no observable effect concentration (NOEC) at 453 µg l,1. Fecundity, as egg viability, was significantly reduced at the LOEC. Survival of parental and progeny generation embryos and mean length, wet weight and dry weight of progeny generation juveniles were not significantly affected at concentrations ,LOEC. TBT, a toxic impurity in DBT reversibly produced in DBT by the process of comproportionation, was also monitored throughout this study. Comparing measured levels of TBT in this study with levels exerting toxic effects in an earlier TBT life-cycle study with C. variegatus suggests biological responses in this study were likely due to the TBT impurity and not to DBT alone. Results indicate that TBT impurity as low as 0.1% may have a significant influence on the perceived toxicity of DBT and that spontaneous production of TBT in DBT may be the major source of biological toxicity of DBT. Copyright © 2003 John Wiley & Sons, Ltd. [source] Urethral in situ biocompatibility of new drug-eluting biodegradable stents: an experimental study in the rabbitBJU INTERNATIONAL, Issue 8 2009Andres Kotsar OBJECTIVE To assess the effect of drug-eluting properties on the degradation process and the biocompatibility of biodegradable drug-eluting urethral stents. MATERIALS AND METHODS Braided biodegradable 80 L/20D-PLGA (copolymer of polylactide and polyglycolide) stents with drug-eluting properties were used as the test material. The drugs analysed were indomethacin, dexamethasone and ciprofloxacine. 80 L/20D-PLGA stents without a drug coating served as controls. In all, 16 male rabbits were used and divided into four groups. The stents were inserted under general anaesthesia into the posterior urethra. After 1 month, the rabbits were killed and the urethra removed for histological and optic microscopy analyses. RESULTS Control stents and the dexamethasone-eluting stents degraded totally during the follow-up period. Conversely, in both indomethacin- and ciprofloxacine-eluting stent groups, the degradation process was significantly delayed and they induced an increase in epithelial hyperplasia. Histological analysis showed that all the stents induced eosinophilia, but there were no significant differences in the intensity of acute or chronic inflammatory reactions and fibrosis. CONCLUSIONS A drug-eluting capacity can be added to biodegradable stents. The addition of a drug influences the biodegradation time of PLGA urethral stents. Further studies are needed, to find the proper concentrations and releasing profiles of the drugs to achieve the desired bioactivity and biocompatibility properties. [source] Type-IV hypersensitivity to betamethasone valerate and clobetasol propionate: results of a multicentre studyBRITISH JOURNAL OF DERMATOLOGY, Issue 2 2002S. Sommer SummaryBackground,Most studies investigating steroid allergy have been performed with tixocortol pivalate, hydrocortisone butyrate and budesonide. Betnovate® and Dermovate® are widely prescribed in the U.K. but little is known about the frequency of sensitization to them. Objectives,To determine the optimum method to detect contact allergy to betamethasone valerate (BV) and clobetasol propionate (CP). Methods,Seven centres tested consecutive patients attending for investigation of suspected allergic contact dermatitis to these steroids at a range of concentrations in different vehicles. Results,Of 1562 patients tested, 16 (1%) reacted to either BV or CP. Ten patients (0·7%) reacted to BV and 13 (0·8%) to CP. Two patients of a further centre were included in analysis of dilutions and vehicles. Sixteen of a total of 25 reactions (64%) were identified with a 1% dilution in ethanol. Conclusions,Consideration should be given to adding BV and CP to a standard allergy series, given that both are frequently used in the treatment of eczema and that most patients sensitized to them are not identified with currently used markers of steroid allergy. If patch tests to BV and CP are initially negative, but an allergy is suspected, the patient should be further investigated. Further studies are required to identify the ideal patch test material. [source] FS01.3 Disperse (yes), orange (yes), 3 (no): what do we test in textile dye dermatitis?CONTACT DERMATITIS, Issue 3 2004Christophe J Le Coz Introduction:, Patients sensitized to para-phenylenediamine (PPD) have a high degree of patch test reactivity to Disperse Orange 3 (DO3), and a lesser one to Disperse Red 1 and Red 17. Two successive patients positive to PPD, Disperse Red 1 and 17, negative to DO3 were real eye-openers for our considerations about purity of our current allergen DO3. Materials and methods:, We realized comparative thin-layer chromatography (TLC), with DO3 from Chemotechnique®(DO3-Chem) and Trolab®(both extracted from petrolatum), and "pure" DO3 from two chemical providers. TLC clearly indicated that DO3-Chem was not DO3. HPLC analysis with pure DO3 from Chemotechnique® and comparison of structures by NMR with samples of DO3, revealed that DO3-Chem was Disperse Orange 31 (DO31). In addition, signals through the GERDA network allowed the collection of test materials and observations. Among other members, only 2 used DO3-Chem (from 2 different batches) that was DO31 too, according to TLC Results: According to their data, they observed no or a lower reactivity to DO3 than expected (4 patients DO3-Chem + among 23 PPD+ e.g.). Finally, the error was proved to be due to the provider of the dye to Chemotechnique®, who likely deleted the 1 of Disperse Orange 31 on his packaging. Discussion:, Chemical structure of DO31 indicates a possible in vivo hydrolysis into nitroaniline and a second compound, a substituted PPD derivative that clearly does not frequently react in PPD positive patients. Like drugs, patch tests are submitted to post-commercialization controls. In addition to allergens providers who should enhance their quality controls, dermato-allergologists have to be vigilant, and must active networks when they observe a rare bird. [source] Contact allergy caused by air oxidation of common materials , diagnosis and preventionCONTACT DERMATITIS, Issue 3 2004Ann-Therese Karlberg When considering the allergenic activity of a compound not only the possibility of bioactivation by skin metabolism but also air activation by autoxidation must be taken into account. Natural compounds (terpenes) easily oxidize at air exposure. They are found in products that are common causes of allergic contact dermatitis (ACD) i.e. colophony and fragrances. The introduction of oxygen enables the molecules to form antigens with skin proteins via a nucleophilic- electrophilic interaction or via a radical reaction. The latter mechanism seems to be important since the primary oxidation products, the hydroperoxides, are the most potent sensitizers formed. Oxidative decomposition at air exposure resulting in allergenic oxidation products is observed also for other common compounds e.g. ethoxylated fatty alcohols used as surfactants. It is important to test the patient with the offending compounds for diagnosis of ACD. A negative diagnosis can be due to failure in testing with the correct substances. In the case of air activated compounds, testing should not be performed with the pure substances but rather with the oxidation mixture or the most sensitizing oxidation products (the hydroperoxides). We have in multicenter-studies shown that the common fragrance terpenes, limonene and linalool, are frequent sensitizers when oxidized. This is a challenge in clinical practice since such patch test materials are not easily standardized. Compounds, easily activated at air exposure, should be prevented from oxidative decomposition by addition of antioxidants and proper handling and storage. More research is needed in this area. [source] Organisation of proficiency testing for plant health diagnostic tests: the experience of FAPAS®EPPO BULLETIN, Issue 1 2010A. Reynolds Proficiency testing (PT) is an established quality assurance measure and is based on the comparison of laboratories' results in an inter-laboratory trial. It highlights problems in laboratory analysis and is an educational tool to help improve data quality. This article describes how PT is organised by FAPAS®. FAPAS® is an international PT provider (external quality assessments) for food chemistry, food microbiology, genetically modified material and water/environmental samples. Since 2007, FAPAS® have organized plant health proficiency tests in conjunction with the Plant Pest and Disease Identification Programme at the Food and Environment Research Agency (Fera). Up until 2009, FAPAS® has organised seven plant health proficiency tests that covered the identification of lyophilised bacteria, viruses in leaves and fungi in agar plugs. In 2009, FAPAS® organized over 10 plant health proficiency tests under the banner of ,PhytoPAS', including Potato spindle tuber viroid, Phytophthora ramorum, Thrips palmi, Erwinia amylovora, Clavibacter michiganensis subsp. sepedonicus, etc. DNA extracts, cyst nematodes (Globodera pallida) and slides/immunofluorescence (IF) slides have been added to the programme. The organization of the plant health proficiency tests follows a similar pattern. Suitable test materials are prepared and tested for quality before distribution to requesting participants. Laboratories usually have 1,2 months to analyze their samples and return their results. A report is then compiled for issue to laboratories and these contain all results in an anonymous form, so that laboratories can compare their results with those of other participants. If a laboratory's performance is unsatisfactory then it is up to them to investigate the situation. Thus, the primary purpose of PT is the detection of inaccuracy in a laboratory's results, so that they can investigate the problems and initiate corrective procedures. [source] Prostaglandin E2 production and viability of cells cultured in contact with freshly mixed endodontic materialsINTERNATIONAL ENDODONTIC JOURNAL, Issue 5 2006K. K. Melegari Abstract Aim, To determine whether commonly used endodontic sealers could either induce or increase the release of prostaglandin E2 (PGE2) when in contact with cell types found in the periapical tissues. Methodology, Freshly mixed samples of Roth 801 sealer, Sealapex® and ProRoot® mineral trioxide aggregate (MTA) were placed in contact with cultured macrophages and fibroblasts for 24 h. The supernatant from the cultures was assayed for PGE2 using enzyme-linked immunosorbent assay. Cell viability counts were made. As a positive control, similar cultures were also exposed to lipopolysaccharide and the supernatant analysed for PGE2. Data were compared by anova. Results, The three materials examined in these experiments did not stimulate increased PGE2 release from either of the cell lines. In control cultures, lipolysaccharide increased PGE2 release from macrophages but not from fibroblasts. Viability counts revealed that, whilst Roth 801 sealer caused some cell death in both fibroblasts and macrophages, Sealapex® led to cell death only in the macrophage cultures. ProRoot® MTA did not lead to statistically significant cell death in either culture. Conclusions, Under 24-h culture conditions, the three freshly mixed test materials did not increase directly either production or release of PGE2 from either macrophages or gingival fibroblasts. Roth 801 decreased cell viability counts for both fibroblasts and macrophages. Sealapex® decreases macrophage viability. ProRoot® MTA did not affect viability in either cell line. [source] Strength of two structured soils in triaxial compressionINTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 2 2001Ron C. K. Wong Abstract Oil sands are dense granular materials with interlocked structure and clay shales are heavily overconsolidated clays. They are classified as structured soil or weak rock, exhibiting high peak strength with severe softening and dilation, particularly at low confining stress. The triaxial compression test results indicate that both materials yield linear Mohr,Coulomb envelopes with an apparent cohesion for peak and residual strengths. However, the strength components mobilized from these two materials are very different. This paper investigates if these strength parameters are intrinsic properties or responses derived in triaxial compression conditions. Computer tomography scanning technique is used to aid in examining the micro-structural features of the sheared specimens such as shear banding pattern, shear band thickness, spatial porosity distributions inside and outside shear bands. These micro-structural features are used to explain the macro-deformation response observed in the triaxial compression tests. Mobilization of strength components derived from interlocked structure, cementation, dilation, rolling and critical state are analysed for pre-, post-peak softening and residual stages. It is found that the empirical correlation such as Mohr,Coulomb failure criterion based on triaxial compression test results does not necessarily reflect the intrinsic properties of the test materials. Testing conditions are embedded in the empirical correlation. Copyright © 2001 John Wiley & Sons, Ltd. [source] Cognitive Screening Using a Tape Recorder: A Pilot StudyJOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 3 2003Peter W. Schofield MD OBJECTIVES: To determine whether a tape recorder can be used to administer cognitive tests efficiently and yield valid results. DESIGN: Convenience sample. Administration of cognitive test materials by tape recorder and conventional technique. SETTING: Outpatient clinic. PARTICIPANTS: Subjects from memory disorder clinic, hostel accommodation, and community. MEASUREMENTS: Responses to Hopkins Verbal Learning Test,revised, verbal fluency items from the controlled oral word association test, 10-item naming task, a construction task, and speed writing task. RESULTS: Performances on the tape- and clinician-administered battery of tests were highly correlated. Memory impairment was accurately detected using the tape battery. Data from 30 minutes of testing via tape were obtained at the cost to the clinician of 2 to 3 minutes of scoring time. CONCLUSION: Tape-administration of cognitive test material warrants further study as an efficient means of cognitive screening. [source] Induced changes in total serum IgE concentration in the Brown Norway rat: potential for identification of chemical respiratory allergensJOURNAL OF APPLIED TOXICOLOGY, Issue 1 2002E. V. Warbrick Abstract A variety of chemicals can cause sensitization of the respiratory tract and occupational asthma that may be associated with IgE antibody production. Topical exposure to chemical respiratory allergens such as trimellitic anhydride (TMA) has been shown previously to induce increases in the total serum concentration of IgE in BALB/c strain mice. Contact allergens such as 2,4-dinitrochlorobenzene (DNCB), which apparently lack respiratory sensitizing potential, fail to provoke similar changes. However, it became apparent with time that there was some inter-animal variation in constitutive and inducible IgE levels. We have now examined the influence of topical exposure to TMA and DNCB on serum IgE levels in the Brown Norway (BN) rat. Such animals can be bled serially and thus it is possible to perform longitudinal analyses of changes in serum IgE concentration. The kinetics of IgE responses therefore can be followed on an individual animal basis, allowing discrimination between transient and sustained increases in serum IgE concentration. Rats (n = 5) were exposed on shaved flanks to 50% TMA, to 1% DNCB (concentrations that elicit comparable immune activation with respect to draining lymph node cellularity and proliferation) or to vehicle alone. Total IgE was measured by enzyme-linked immunosorbent assay in serum samples taken prior to and 14,42 days following initial exposure. Those animals having high pre-existing IgE levels (>1.0 µg ml,1) were excluded from subsequent analyses. The levels of serum IgE in the majority of rats exposed to DNCB or vehicle alone remained relatively stable throughout the duration of all the experiments conducted, although some animals displayed transient increases in serum IgE. Only TMA treatment was associated with a significant and sustained increase in the level of serum IgE in the majority of experiments. The elevated concentrations of IgE induced by topical exposure to TMA are persistent, the results reported here demonstrating that induced changes in IgE are maximal or near maximal at approximately 35 days, with a significant increase in IgE demonstrable for at least 42 days following the initiation of exposure. Interestingly, although TMA and DNCB at the test concentrations used were found to be of comparable overall immunogenicity with regard to lymph node activation and the induction of lymph node cell proliferation, there were apparent differences in humoral immune responses. Thus, not only did exposure to TMA stimulate increases in total serum IgE concentration and the production of specific IgE antibody, but also a more vigorous IgG antibody response was provoked by TMA compared with DNCB. These data suggest that the measurement of induced changes in serum IgE concentration in the BN strain of rat is able to differentiate between different classes of chemical allergen. Given the inter-animal variation in IgE production, it would be prudent to incorporate a concurrent assessment of responses induced by treatment with TMA as a positive control against which to assess the activity of other test materials. Copyright © 2002 John Wiley & Sons, Ltd. [source] Antibacterial effect of silver-zeolite containing root-canal filling materialJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2009Abstract The aim of this study was to determine the in vitro antibacterial effect of two experimental glass ionomer cements (GICs) on Streptococcus milleri, Staphylococcus aureus, and Enterococcus faecalis after 24 and 48 h incubation by using the agar diffusion inhibitory test. Silver zeolite (SZ) was added at 0.2 and 2% mass fraction concentration to GIC (Endion). The control group was Endion with no SZ. Each of them were prepared to uniform size using a custom-made Teflon mold, and the GIC materials were prepared to form disks (n = 5 per group). The effect of these materials on the growth of three bacteria associated with endodontic infections was determined using the agar diffusion inhibitory test. The amounts of silver ion release from these materials were measured with atomic absorption spectrophotometry at 10 min, 24- and 48-h periods. The pH of samples was measured with a pH-meter at 10 min, 24- and 48-h periods. After the incubation period, the agar plates were evaluated and the degrees of bacterial inhibition were measured in millimeters. A comparison of the mean of the test materials was statistically different in each group of specimens (p < 0.05). Between the two tested materials 2% SZ containing GIC showed the largest zone of inhibition on the agar plates of all the tested strains (p < 0.05). The most inhibition in bacterial growth occurred in E. faecalis. Adding 2% SZ to GIC resulted in a significant increase in the silver release into deionized water. This study demonstrated that GIC had an inhibitory affect on Streptococcus milleri, Staphylococcus aureus, and Enterococcus faecalis and that adding SZ increases that affect proportional to its concentration. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009 [source] Cell-type specific evaluation of biocompatibility of commercially available polyurethanesJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 1 2009Karla Lehle Abstract The biocompatibility of different commercially available poly(ether)urethane (PUR), medically used as main component for pump chambers of implantable ventricular assist devices (VAD), was evaluated. We investigated the influence of the PUR manufacturing process in an in vitro cytotoxicity screening assay. Human saphenous vein endothelial cells (HSVEC) and a mouse fibroblast cell line (L929) were cultivated with different PUR specimens. Tissue-cultured polystyrole (TCP) was used as a reference. The cytotoxic effect was evaluated by morphology (phase contrast microscopy), cell viability (mitochondrial acitvity), cell growth kinetics, and proliferation (incorporation of 3H-methyl-thymidine) tests. Fibronectin-coating guaranteed the adhesion of both cell types onto the reference material. Sterilization procedure of test materials did not affect adhesion properties. L929 completely covered the surfaces of Tecothane®, Carbothane®, and Mecora specimens, whereas HSVEC formed an imperfect monolayer onto the PUR. The mitochondrial activity was reduced in all cell types attached to PUR. In addition, proliferation of cells was not observed when using these materials. Commercially available PUR provided an unfavorable support for colonization of patient-derived HSVEC, which demanded a surface modification. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009 [source] The chick chorioallantoic membrane as a novel in vivo model for the testing of biomaterialsJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2002T.I. Valdes Abstract Current in vivo models for testing biomaterials are time and labor intensive as well as expensive. This article describes a new approach for testing biomaterials in vivo using the chorioallantoic membrane (CAM) of the developing chicken embryo, as an alternative to the traditional mammalian models. Fertilized chicken eggs were incubated for 4 days, at which time a small window was cut in the shell of the egg. After 1 week of incubation, the CAM received several test materials, including the endotoxin LPS, a cotton thread and a Silastic tubing. One day and 1 week later, the tissue response to the test materials was assessed using gross, histological, and scanning electron microscope evaluations. The inflammatory response of the chorioallantoic membrane to biomaterials was fully characterized and found to be similar to that of the mammalian response and was also seen to vary according to test materials. We also found that the structure and geometry of the test materials greatly influenced the incorporation of the samples in the CAM. The similarity of the tissue response of the CAM with the mammalian models, plus the low cost, simplicity, and possibility to continuously visualize the test site through the shell window make this animal model particularly attractive for the rapid in vivo screening of biomaterials. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 62: 273,282, 2002 [source] INFLUENCE OF MEASUREMENT TECHNIQUE, TEST FOOD, TEETH AND MUSCLE FORCE INTERACTIONS IN MASTICATORY PERFORMANCEJOURNAL OF TEXTURE STUDIES, Issue 1 2007FLÁVIA RIQUETO GAMBARELI ABSTRACT The role of texture and flavors in mastication is evident, but it is difficult to understand the interactions among food properties, oral physiology and perception. Mastication results from rhythmic mandibular movements. The teeth and masticatory muscles together form the mechanism whereby the food particles are fragmented. Masticatory performance and efficiency are defined as the capacity to reduce natural or artificial test materials during mastication, or by counting the number of strokes required to reduce food, respectively. Foods eaten for nourishment are very different from the industrial test materials used to quantify masticatory performance, thus, divergences could arise if the chewable material can or cannot be swallowed. This study presents a synopsis of masticatory performance methods, which is also related to muscle force, number of teeth and test chewing substance diversity. PRACTICAL APPLICATIONS The attributes of food, such as appearance, flavor and texture, as well as its interaction with saliva, number of teeth and conditions of the biomechanical system, influence the chewing process. In addition, reflex control and cognition can influence food perception and breakdown in the mouth. Food acceptability and choice depend on sensory properties of the food, which are perceived during chewing and swallowing. Masticatory performance and maximal occlusal force measurement may provide essential information that could lead to an appropriate diagnosis as regards masticatory function. Masticatory efficiency and performance can be measured to determine the individual's capacity to comminute a natural or a chewable test material. A material with uniform properties that can be reliably reproduced is essential to provide an ideal test bolus for the scientific study of masticatory effectiveness. [source] A critical review of methodologies used in determination of relative bio-availability ratio of RRR -,-tocopheryl acetate and all - rac -,-tocopheryl acetateJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 10 2010Yueming Dersjant-Li Abstract Bio-availability of different ,-tocopherol forms in livestock animals is measured by the increase in plasma or tissue concentrations of ,-tocopherol after oral administration. It is generally accepted that RRR -,-tocopheryl acetate (natural source vitamin E derived from vegetable oil) has a higher bio-availability compared to all - rac -,-tocopheryl acetate (synthetic vitamin E, i.e. ,-tocopherol produced by chemical synthesis). However, different bio-availability ratios have been reported in the literature. The major reason for conflicting results in literature studies was the inability to separate the proportion of ,-tocopherol originating from test materials, from the proportion of ,-tocopherol originating from basal dietary ingredients and pre-feeding. This causes significant variability. For bio-availability determination, a baseline or control treatment is essential. The estimation of bio-availability without correction for basal vitamin E status will lead to incorrect interpretation of the results. When using proper methodologies, it is possible to correct for the impact of ,-tocopherol intake from basal ingredients and ,-tocopherol originating from pre-feeding, therefore yielding results reflecting the true relative bio-availability of different ,-tocopherol substances. When reviewing literature data a critical evaluation of the method used in determination of relative bio-availability is recommended. Copyright © 2010 Society of Chemical Industry [source] Comparison of PDQuest and Progenesis software packages in the analysis of two-dimensional electrophoresis gelsPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 10 2003Arsi T. Rosengren Abstract Efficient analysis of protein expression by using two-dimensional electrophoresis (2-DE) data relies on the use of automated image processing techniques. The overall success of this research depends critically on the accuracy and the reliability of the analysis software. In addition, the software has a profound effect on the interpretation of the results obtained, and the amount of user intervention demanded during the analysis. The choice of analysis software that best meets specific needs is therefore of interest to the research laboratory. In this paper we compare two advanced analysis software packages, PDQuest and Progenesis. Their evaluation is based on quantitative tests at three different levels of standard 2-DE analysis: spot detection, gel matching and spot quantitation. As test materials we use three gel sets previously used in a similar comparison of Z3 and Melanie, and three sets of gels from our own research. It was observed that the quality of the test gels critically influences the spot detection and gel matching results. Both packages were sensitive to the parameter or filter settings with respect to the tendency of finding true positive and false positive spots. Quantitation results were very accurate for both analysis software packages. [source] Quantitative Analysis of Human Platelet Adhesions Under a Small-Scale Flow DeviceARTIFICIAL ORGANS, Issue 4 2010Katsuko S. Furukawa Abstract To realize real-time evaluation of human platelet adhesions onto material surfaces with small volumes of human platelet suspensions, we developed an apparatus consisting of a modified cone and plate-type viscometer, combined with an upright epi-fluorescence microscope. The apparatus allowed real-time evaluation of platelet,material interactions and the initial event of thrombus formation, using small platelet suspension volumes (7.5 µL) under shear flow conditions. To study the dynamic behavior of platelet,material interaction, we chose five representative opaque and transparent materials: acrylate resin (AC), polytetrafluoroethylene (PTFE), polyvynylchrolide (PVC), glass, and a monolayer of human normal umbilical cord vein endothelial cells (EC) on glass under shear flow conditions. The values of adhesiveness of human platelets to the test materials in descending order were as follows: AC > PTFE > PVC > glass > human EC. Under this new small-scale flow system, we could obtain highly reproducible data, which were comparable with results from a previously developed large-scale flow system. Therefore, the newly developed cone and plate-type rheometer is a useful instrument for testing and screening materials, and allows precise quantitative evaluation of human platelet adhesion. [source] An Animal Study of a Newly Developed Skin-Penetrating Pad and Covering Material for Catheters to Prevent Exit-Site Infection in Continuous Ambulatory Peritoneal DialysisARTIFICIAL ORGANS, Issue 12 2009Masato Aoyama Abstract Because currently available peritoneal dialysis catheters are not sufficiently biocompatible with the skin and subcutaneous tissue at the site of penetration, exit-site infection due to pericatheter pocket formation caused by epidermal downgrowth over a long period of time has increasingly become a problem. We developed a new, biocompatible, segmented polyurethane porous material and devised a novel skin-penetrating pad, the form and material of which we optimized for application in peritoneal dialysis catheters. For the extent of tissue ingrowth into this porous material to be examined, test materials with different pore diameters were inserted into hollow silicone tubes and implanted in the subcutaneous tissue of a goat. Four weeks later, the tubes were extracted, and, after the extent of granulation tissue ingrowth was measured, histopathological evaluation was made. Our novel skin-penetrating pad has three disklike layers of the segmented polyurethane material with different pore sizes, into the center of which a polyurethane catheter is inserted. These pads were implanted in the skin of a goat and clinically observed over a 2-year period, after which they were extracted and histopathologically analyzed. In accordance with actual clinical procedures, a commercial CAPD catheter equipped with our skin-penetrating pad was left indwelling in a goat for 4 months, and the performance of the pad was evaluated after repeated periodic infusion and drainage of the dialysate in and out of the abdominal cavity. There was no inflammation of the ingrown tissue in the pores of the segmented polyurethane material as well as the surrounding tissue, which indicated favorable tissue biocompatibility. The extent of tissue ingrowth was greater as the pore size of the material was larger, and the tissue tended to be mature, mainly consisting of collagenous fibers. The skin-penetrating pad using the porous material, of which tissue ingrowth was thus optimized, tightly adhered to the goat skin throughout the 2-year experimental period without any special wound care such as cleansing or disinfection. The performance of the skin-penetrating pad was similarly favorable when attached to a commercial continuous ambulatory peritoneal dialysis catheter. The newly developed segmented polyurethane porous material had excellent tissue biocompatibility and tissue ingrowth. The skin-penetrating pad devised by using this porous material did not cause epidermal downgrowth, suggesting that it may be effective for the prevention of exit-site infection. [source] | ||||||||||||||||||||||