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Shrinkage
Kinds of Shrinkage Terms modified by Shrinkage Selected AbstractsEFFECT OF A LIGHT-EMITTING DIODE ON COMPOSITE POLYMERIZATION SHRINKAGE AND HARDNESSJOURNAL OF ESTHETIC AND RESTORATIVE DENTISTRY, Issue 2 2005Kraig S. Vandewalle DDS [source] CORRELATING SHRINKAGE WITH YIELD, WATER CONTENT AND TEXTURE OF PORK HAM BY COMPUTER VISIONJOURNAL OF FOOD PROCESS ENGINEERING, Issue 3 2005CHENG-JIN DU ABSTRACT An automatic method for shrinkage evaluation of pork ham was developed using computer vision. First, a sequence of image-processing algorithms was developed to estimate the average diameter, short axis, long axis, perimeter, volume and surface area before and after cooking and cooling. This sequence consisted of three steps, i.e., shape extraction, protrusion deletion and measurement. Based on the estimated shape characteristics, three kinds of shrinkage were evaluated as the percentage change before and after a process, i.e., shrinkages caused by the cooking process, cooling process and total shrinkage during the entire cooking and cooling processes. Then the cooking shrinkage was related to cooking loss; the cooling shrinkage to cooling loss and the total shrinkage to yield, water content and texture. It was found that among the three shrinkages, the cooking shrinkage in volume was the highest with up to 9.36%, and was significantly correlated with cooking loss (r = 0.91). The total shrinkage was highly negatively correlated with water content, and had positive correlations with the texture attributes. However, no significant relationships were found between cooling shrinkage and cooling loss, and between total shrinkage and yield. [source] MODELING DIMENSIONAL SHRINKAGE OF SHAPED FOODS IN FLUIDIZED BED DRYINGJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 2 2005WIJITHA SENADEERA ABSTRACT Three particular geometrical shapes of parallelepiped, cylinder and sphere were selected from cut beans (length : diameter = 1:1, 2:1, 3:1), potatoes (aspect ratio = 1:1, 2:1, 3:1) and peas, respectively. The dimensional shrinkage behavior was studied in a batch fluidized bed at three drying temperatures of 30, 40 and 50C. Relative humidity of hot air was kept at 15%. Dimensional shrinkage was plotted using a nondimensional moisture ratio and the shrinkage behavior of the selected foods was modeled with simple mathematical models. [source] PREDICTION OF APPLE FIRMNESS FROM MASS LOSS AND SHRINKAGEJOURNAL OF FOOD QUALITY, Issue 1 2004S.O. LINK ABSTRACT Prediction of firmness from mass loss and shrinkage was investigated in apples (Malus x domestica Borkh.) under regular atmosphere (RA) storage conditions. Apples (,Delicious' and ,Fuji') were repeatedly weighed to determine mass loss. Shrinkage was measured with a strain gauge sensor. ,Delicious' apples lost firmness (73 to 58 N) while ,Fuji' apples maintained firmness at 69 N over 57 days in storage. Apples lost mass at a constant rate with ,Delicious' losing mass slower (0.6 % per month) than ,Fuji' (1.1% per month). ,Delicious' apple shrank less (0.28 mm) than the ,Fuji' (0.70 mm) over 57 days. The relationship between firmness and mass loss, or shrinkage was dependent on apple cultivar. Firmness was significantly and linearly related to mass loss and to shrinkage in ,Delicious' apples. It is possible to predict firmness of ,Delicious' apples under RA storage conditions by tracking mass loss or shrinkage. [source] Changes in shrinkage of restored soil caused by compaction beneath heavy agricultural machineryEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 4 2008B. Schäffer Summary Compaction is a major cause of soil degradation. It affects not only the porosity of the soil, but also the soil's hydrostructural stability. Soil that is restored after temporary removal is particularly sensitive to compaction. We investigated the effects of trafficking with a heavy combine harvester on the shrinkage behaviour of a restored soil that had been gently cultivated for several years. We tested the hypothesis that compaction decreases the hydrostructural stability of restored soil by analysing simultaneously measured shrinkage and water retention curves of undisturbed soil samples. Shrinkage strongly depended on clay and organic carbon content. Taking account of this influence and normalizing the shrinkage parameters with respect to these soil properties, we found pronounced effects of trafficking on shrinkage. Ten passes with the combine harvester decreased the structural porosity by about 40% at maximum swelling and by about 30% at the shrinkage limit and increased the bulk density by 8% at maximum swelling and by 10% at the shrinkage limit, but did not significantly affect the porosity of the soil plasma. Moreover, trafficking modified shrinkage, increasing the slopes of the shrinkage curve in the basic and structural shrinkage domains by about 30% and more than 150% after 10 passes, respectively. Evidently the aggregate structure was strongly destabilized. The results indicate that the hydrostructural stability of the soil was still very sensitive to compaction by trafficking even 5 years after restoration. The analysis of shrinkage seemed well suited for the assessment of compaction effects on soil structure. [source] Shrinkage of initially very wet soil blocks, cores and clods from a range of European Andosol horizonsEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 2 2007F. Bartoli Summary In advanced stages of volcanic ash soil formation, when more clay is formed, soil porosity values and soil water retention capacities are large and the soils show pronounced shrinkage on drying. Soil shrinkage is a key issue in volcanic soil environments because it often occurs irreversibly when topsoils dry out after changes from permanent grassland or forest to agriculture. European Andosols have developed in a wide range of climatic conditions, leading to a wide range in intensity of both weathering and organo-mineral interactions. The question arises as to whether these differences affect their shrinkage properties. We aimed to identify common physically based shrinkage laws which could be derived from soil structure, the analysis of soil constituents, the selected sampling size and the drying procedure. We found that the final volumetric shrinkage of the initially field-wet (56,86% of total porosity) or capillary-wet (87,100% of total porosity) undisturbed soil samples was negatively related to initial bulk density and positively related to initial capillary porosity (volumetric soil water content of soil cores after capillary rise). These relationships were linear for the soil clods of 3,8 cm3, with final shrinkage ranging from 21.2 to 52.2%. For soil blocks of 240 cm3 and soil cores of 28.6 cm3 we found polynomial and exponential relationships, respectively, with thresholds separating shrinkage and nearly non-shrinkage domains, and larger shrinkage values for the soil cores than for the soil blocks. For a given sample size, shrinkage was more pronounced in the most weathered and most porous Andosol horizons, rich in Al-humus, than in the less weathered and less porous Andosol horizons, poor in Al-humus. The Bw horizons, being more weathered and more porous, shrank more than the Ah horizons. We showed that the structural approach combining drying kinetics under vacuum, soil water analysis and mercury porosimetry is useful for relating water loss and shrinkage to soil structure and its dynamics. We also found that the more shrinkage that occurred in the Andosol horizon, the more pronounced was its irreversible mechanical change. [source] Process Shrinkage and Accuracy during Indirect Laser Sintering of Aluminium,ADVANCED ENGINEERING MATERIALS, Issue 4 2006B. Sercombe In this paper we have investigated the shrinkage and accuracy of indirect selective laser sintered aluminium. The majority of the ,1.2-1.4% linear shrinkage occurs during the infiltration of the skeleton structure. By optimising scale and offset parameters during selective laser sintering of the preforms, accuracy similar to that of casting processes can be achieved. [source] Near Zero Shrinkage of an Low-Temperature Co-Fired Ceramic Package by Constrained Sintering Using Screen Printed Alumina PasteINTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY, Issue 2010Sang Myoung Lee Conventional free sintering of low-temperature co-firing ceramic (LTCC) technology has several merits such as sintering temperature below 1000°C that enables co-firing with electrode materials of silver or copper metal and multilayer structure formation. But due to the free sintering process, large shrinkage occurs. To fabricate electronic devices and components with near zero shrinkage within x, y directions constrained sintering (CS) technology is required. In this study a constrained sintering paste (CSP) utilizing alumina powder, which has a higher sintering temperature than LTCC powders, was fabricated for CS technology. The effect of CSP formulated using alumina powder on shrinkage was studied according to variation in paste composition. As a result ceramic package structure with a cavity was fabricated with shrinkage control of 0.028%, which is far smaller than the current CS technology shrinkage of approximately 0.1%. [source] Zero Shrinkage of LTCC by Self-Constrained SinteringINTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY, Issue 5 2005Torsten Rabe Low shrinkage in x and y direction and low tolerances of shrinkage are an indispensable precondition for high-density component configuration. Therefore, zero shrinkage sintering technologies as pressure-assisted sintering and sacrificial tapes have been introduced in the low-temperature co-fired ceramics (LTCC) production by different manufacturers. Disadvantages of these methods are high costs of sintering equipment and an additional process step to remove the sacrificial tapes. In this article, newly developed self-constrained sintering methods are presented. The new technology, HeraLock®, delivers LTCC modules with a sintering shrinkage in x and y direction of less than 0.2% and with a shrinkage tolerance of ±0.02% without sacrificial layers and external pressure. Each tape is self-constrained by integration of a layer showing no shrinkage in the sintering temperature range of the LTCC. Large area metallization, integration of channels, cavities and passive electronic components are possible without waviness and camber. Self-constrained laminates are an alternative way to produce zero shrinkage LTCC. They consist of tapes sintering at different temperature intervals. Precondition for a successful production of a self-constrained LTCC laminate is the development of well-adapted material and tapes, respectively. This task is very challenging, because sintering range, high-temperature reactivity and thermal expansion coefficient have to be matched and each tape has to fulfill specific functions in the final component, which requires the tailoring of many properties as permittivity, dielectric loss, mechanical strength, and roughness. A self-constrained laminate is introduced in this article. It consists of inner tapes sintering at especially low-temperature range between 650°C and 720°C and outer tapes with an as-fired surface suitable for thin-film processes. [source] Physicochemical, textural, sensory characteristics and storage stability of goat meat patties extended with full-fat soy paste and soy granulesINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 3 2008Arun K. Das Summary The performance of full-fat soy paste (FFSP) with reduced beany flavour made by simple processing technology was compared with the commercially available textured soy granules in goat meat patties. Addition of soy proteins (soy paste and soy granules) did not significantly affect the emulsion stability and product yield. Shrinkage of patties with soy paste was comparable with control. A significant (P < 0.05) reduction in redness and increase in yellowness of patties was due to addition of soy proteins than in control. Patties with soy paste had comparable but slightly higher total lipid and cholesterol content with that of control but significantly (P < 0.05) higher than patties with soy granules. Lower force was required to compress or shear the sample, as hardness decreased in soy-added patties. Flavour and overall acceptability scores between control and patties with soy paste did not differ significantly, whereas patties with soy granules were rated significantly lower. The patties remained stable with minor changes in physicochemical, microbiological and sensory quality during refrigerated storage (4 ± 1 °C) for 20 days. It is concluded from this study that FFSP had potential application similar to commercially available textured soy granules in comminuted meat products. [source] Structural changes and shrinkage of potato during fryingINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 1 2001Rui M. Costa Summary Light microscopy was used to study changes in cell size, blister formation and crust evolution during potato frying. Frying experiments with both French fries and crisps of different thickness (1,5 mm) were performed at temperatures of 140 and 180 °C. Thickness, volume and density changes were also measured. The formation of crust in French fries starts after the potato surface reached approximately 103 °C, and then the crust thickness increased linearly with the square root of frying time, this increase being faster at 180 °C. The potato volume decreased during frying, although in the late stages the volume may increase because of oil uptake and cell separation caused by entrapped water vapour. Shrinkage was adequately described by the Weibull model with a residual value, with shrinkage rate increasing with temperature and decreasing with potato thickness. The residual volume was not affected by temperature (65% for French fries and 59,30 for crisps, depending on thickness). Volume appeared to decrease mainly as the result of water loss, except for very low water content, and thus potato density changes were very small. [source] Re: Kerns MJJ, Darst MA, Olsen TG, Fenster M, Hall P, Grevey S. Shrinkage of cutaneous specimens: formalin or other factors involved?JOURNAL OF CUTANEOUS PATHOLOGY, Issue 9 2009Gene K. Potter MD [source] PREDICTION OF APPLE FIRMNESS FROM MASS LOSS AND SHRINKAGEJOURNAL OF FOOD QUALITY, Issue 1 2004S.O. LINK ABSTRACT Prediction of firmness from mass loss and shrinkage was investigated in apples (Malus x domestica Borkh.) under regular atmosphere (RA) storage conditions. Apples (,Delicious' and ,Fuji') were repeatedly weighed to determine mass loss. Shrinkage was measured with a strain gauge sensor. ,Delicious' apples lost firmness (73 to 58 N) while ,Fuji' apples maintained firmness at 69 N over 57 days in storage. Apples lost mass at a constant rate with ,Delicious' losing mass slower (0.6 % per month) than ,Fuji' (1.1% per month). ,Delicious' apple shrank less (0.28 mm) than the ,Fuji' (0.70 mm) over 57 days. The relationship between firmness and mass loss, or shrinkage was dependent on apple cultivar. Firmness was significantly and linearly related to mass loss and to shrinkage in ,Delicious' apples. It is possible to predict firmness of ,Delicious' apples under RA storage conditions by tracking mass loss or shrinkage. [source] Development of a Method to Produce Freeze-Dried Cubes from 3 Pacific Salmon SpeciesJOURNAL OF FOOD SCIENCE, Issue 5 2010Charles Crapo Abstract:, Freeze-dried boneless skinless cubes of pink (Oncorhynchus gorbuscha), sockeye (Oncorhynchus nerka), and chum (Oncorhynchus keta),salmon were prepared and physical properties evaluated. To minimize freeze-drying time, the kinetics of dehydration and processing yields were investigated. The physical characteristics of the final product including bulk density, shrinkage, hardness, color, and rehydration kinetics were determined. Results showed that freeze-dried salmon cubes from each of the 3 Pacific salmon species can be produced with a moisture content of less that 10% and,aw,less 0.4 and freeze-drying time of 9 h. Processing yields ranged from 26% to 28.4%, depending on fish species. Shrinkage was less than 12% and rehydration of freeze-dried cubes was rapid. The value-added products developed have the potential to be utilized as ingredients for ready-to-eat soups, as snack food, salad topping, and baby finger-food. Practical Application:, Freeze-drying removes water from food products without heating them; therefore, this type of drying process yields very high-quality dried foods. In this study, a freeze-dry process was established to produce small cubes of Alaska pink, sockeye, and chum salmon. The goals were to shorten typical freeze-drying time while producing acceptable product characteristics. The freeze-drying process developed took only 9 h to remove about 97% of the moisture of diced Pacific salmon fillets. The freeze-dried salmon cubes produced can be used as ingredients for dehydrated ready-to-eat soups, as baby finger-foods, or as salad toppings. [source] A Novel Method for Air Drying Aloe Leaf Slices by Covering with Filter Papers as a Shrink-Proof LayerJOURNAL OF FOOD SCIENCE, Issue 9 2009S.A. Kim ABSTRACT:, To prevent the shrinkage of aloe vera slices during air drying, a method utilizing a shrink-proof layer was developed. The sample was configured of whole leaf aloe slices, where 1 side or both sides were covered with filter papers as shrink-proof layers. After air drying by varying the air temperature and the slice thickness, the drying characteristics, as well as several quality factors of the dried aloe vera leaf slices, were analyzed. In the simulation of the drying curves, the modified Page model showed the best fitness, representing a diffusion-controlled drying mechanism. Nonetheless, there was a trace of a constant-rate drying period in the samples dried by the method. Shrinkage was greatly reduced, and the rehydration ratios increased by approximately 50%. Scanning electron microscopic analysis revealed that the surface structure of original fibrous form was well sustained. FT-IR characteristics showed that the dried samples could sustain aloe polysaccharide acetylation. Furthermore, the functional properties of the dried slices including water holding capacity, swelling, and fat absorption capability were improved, and polysaccharide retention levels increased by 20% to 30%. Therefore, we concluded that application of shrink-proof layers on aloe slices provides a novel way to overcome the shrinkage problems commonly found in air drying, thereby improving their functional properties with less cost. Practical Application: This research article demonstrates a novel air drying method using shrink-proof layers to prevent the shrinkage of aloe slices. We analyzed extensively the characteristics of shrinkage mechanism and physical properties of aloe flesh gels in this drying system. We concluded that this method can be a beneficial means to retain the functional properties of dried aloe, and a potential alternative to freeze drying, which is still costly. [source] Age-Related Gray Matter Shrinkage in a Treatment Naïve Actively Drinking Alcohol-Dependent SampleALCOHOLISM, Issue 1 2010George Fein Background:, We previously demonstrated, in a small sample, steeper age-related gray matter shrinkage in treatment naïve alcohol-dependent (TxN) men compared to nonalcoholic controls, but could not separate out the contributions of age and lifetime duration of alcohol use (which were highly correlated) to this effect. In the current study, we have quadrupled the sample size and expanded it to include both men and women to try to replicate and extend the previous findings and to separate the contributions of age and alcohol use to the phenomenon. Methods:, In the current study, we examine cortical gray matter volumes in 18- to 50-year-old TxN (n = 84) versus age and gender comparable controls (n = 67). We used a new Region of Interest Analysis method which accounts for differences in sulcal and gyral enfolding between individuals (Fein et al., 2009a). Results:, We found greater age-related gray matter shrinkage in TxN than in controls. Partial correlation analysis showed that the effect was a function of age and not lifetime alcohol burden. Conclusions:, Implications of the findings are discussed in terms of their contribution toward our knowledge of differences between different subpopulations of alcoholics and in terms of their implications for the morbidity of alcohol dependence in an aging national population. [source] Copolymerization of diglycidyl ether of bisphenol A with ,-butyrolactone catalyzed by ytterbium triflate: Shrinkage during curingJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 18 2003Cristina Mas Abstract Diglycidyl ether of bisphenol A (DGEBA) was cured with ,-butyrolactone (,-BL) with ytterbium triflate as a catalyst. The curing was studied with differential scanning calorimetry, Fourier transform infrared (FTIR), and thermomechanical analysis. FTIR studies confirmed that four elemental reactions took place during the curing process: the formation of a spiroorthoester (SOE) by the reaction of DGEBA with ,-BL, the homopolymerization of SOE, the homopolymerization of DGEBA, and the copolymerization of SOE and DGEBA. Moderate proportions of ,-BL produced materials with higher glass-transition temperatures, and the curing occurred with lower shrinkage after gelation because of the polymerization of SOE, with near-zero shrinkage during the final stages of the curing. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2794,2808, 2003 [source] Preparation, characterisation and modification of carbon-based monolithic rods for chromatographic applicationsJOURNAL OF SEPARATION SCIENCE, JSS, Issue 9 2010Ali H. Eltmimi Abstract A range of porous carbon-based monolithic (PCM) rods with flow-through pore sizes of 1, 2, 5 and 10,,m, were produced using a silica particle template method. The rods were characterised using SEM and energy-dispersive X-ray spectroscopy, BET surface area and porous structure analysis, dilatometry and thermal gravimetry. SEM evaluation of the carbon monolithic structures revealed an interconnected rigid bimodal porous structure and energy-dispersive X-ray spectroscopy analysis verified the quantitative removal of the embedded silica beads. The specific surface areas of the 1, 2, 5 and 10,,m rods were 178, 154, 84 and 125,m2/g after pyrolysis and silica removal, respectively. Shrinkage of the monolithic rods during pyrolysis is proportional to the particle size of the silica used and ranged from 9 to 12%. Mercury porosimetry showed a narrow distribution of pore sizes, with an average of ,700,nm for the 1,,m carbon monolith. The suitability of bare and surface oxidised PCM rods for the use as a stationary phase for reversed and normal phase LC was explored. The additional modification of PCM rods with gold micro-particles followed by 6-mercaptohexanoic acid was performed and ion-exchange properties were evaluated. [source] Processing Conditions and Aging Effect on the Morphology of PZT Electrospun Nanofibers, and Dielectric Properties of the Resulting 3,3 PZT/Polymer CompositeJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 11 2009Ebru Mensur Alkoy Lead zirconate titanate (PZT) nanofibers are obtained by electrospinning a sol,gel based solution and polyvinyl pyrrolidone (PVP) polymer, and by subsequent sintering of the electrospun precursor fibers. The average diameter of the precursor PZT/PVP green fibers has increased with the aging of the precursor solution along with an increase in the viscosity. Bead-free uniform green PZT/PVP fibers were collected at about an ,230 nm average fiber diameter using a 28 wt% PVP ratio solution with a viscosity of 290 mPa. Shrinkage of 40% was recorded on the fiber diameter after sintering. The X-ray diffraction pattern of the annealed PZT fibers exhibits no preferred orientation and a perovskite phase. Preparation of 3,3 nanocomposites by the infusion of polyvinylester into the nanofiber mat facilitates successful handling of the fragile mats and enables measurements of the dielectric properties. The dielectric constant of the PZT/polyvinylester nanocomposite of about 10% fiber volume fraction was found to be fairly stable and vary from 72 to 62 within the measurement range. The dielectric loss of the composite is below 0.08 at low frequencies and reaches a stable value of 0.04 for most of the measured frequencies. [source] Humidity-Responsive Starch-Poly(methyl acrylate) FilmsMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 7 2008Julious L. Willett Abstract Blown films prepared from starch-poly(methyl acrylate) graft copolymers plasticized with urea and water display shrinkage at relative humidities greater than 50%. Shrinkage at relative humidities below approximately 75% is strongly correlated with the urea/starch weight ratio, which controls the equilibrium moisture content (MC) in the films. Above 75% relative humidity, film shrinkage is essentially independent of composition. At relative humidities below 90%, films plasticized with urea and water exhibited greater shrinkage than films plasticized with water only. A master curve can be constructed by shifting shrinkage data with respect to a reference relative humidity, indicating that relaxation processes in the starch phase control film shrinkage. This conclusion is confirmed by the fact that shrinkage data for a wide range of compositions and relative humidities fall on a single curve when plotted against MC. Polarized Fourier transform infrared spectroscopy indicated some loss of orientation in the starch phase during shrinkage. These results demonstrate that the hydrophilic nature of starch can be exploited to develop responsive polymers which display controllable shrinkages activated by increases in relative humidities. [source] Shrinkage of germinoma by dexamethasone onlyPEDIATRIC BLOOD & CANCER, Issue 5 2008Amirhadi Masoudi MD No abstract is available for this article. [source] Real-time monitoring of injection molding for microfluidic devices using ultrasoundPOLYMER ENGINEERING & SCIENCE, Issue 4 2005Y. Ono Real-time process monitoring of the fabrication process of microfluidic devices using a polymer injection molding machine was carried out using miniature ultrasonic probes. A thick piezoelectric lead-zirconate-titanate film as an ultrasonic transducer (UT) was fabricated onto one end of a 4-mm diameter and 12-mm long steel buffer rods using a sol gel spray technique. The center frequency and 6 dB bandwidth of this UT were 17 MHz and 14 MHz, respectively. A signal-to-noise ratio of more than 30 dB for ultrasonic signals reflected at the probing end was achieved. The probe can operate continuously at 200°C without ultrasonic couplant and cooling. Clear ultrasonic signals were obtained during injection molding of a 1-mm-thick part having test patterns on its surface. Shrinkage of the molded part and part detachment from the mold were successfully monitored. Surface imperfections of the molded parts due to a lack of the sufficient holding pressure is discussed with regard to the ultrasonic velocity obtained. The presented ultrasonic probes and technique enable on-line quality control of the molded part by optimizing the holding pressure and improvement of process efficiency by reducing the cycle time. POLYM. ENG. SCI., 45:606,612, 2005. © 2005 Society of Plastics Engineers [source] Chlorination of C86 to C84Cl32 with Nonclassical Heptagon-Containing Fullerene Cage Formed by Cage Shrinkage,ANGEWANDTE CHEMIE, Issue 28 2010Geschrumpftes Fulleren: Ein ungewöhnlicher C84 -Fullerenkäfig mit siebengliedrigem Ring liegt in C84Cl32 vor, das (neben C86(16)Cl28) bei der Chlorierung von C86(16) mit VCl4 gebildet wird. Ein Vergleich der Strukturen von C84Cl32 (siehe Bild; C grau, Cl grün; rote Bindungen markieren das Heptagon) und C86(16)Cl28 sowie theoretische Studien zeigen, dass der C86(16)-Käfig schrumpft, wenn eine C2 -Einheit aus dem Corranulen-Fragment entfernt wird. [source] Bayesian Semiparametric Multiple ShrinkageBIOMETRICS, Issue 2 2010Richard F. MacLehose Summary High-dimensional and highly correlated data leading to non- or weakly identified effects are commonplace. Maximum likelihood will typically fail in such situations and a variety of shrinkage methods have been proposed. Standard techniques, such as ridge regression or the lasso, shrink estimates toward zero, with some approaches allowing coefficients to be selected out of the model by achieving a value of zero. When substantive information is available, estimates can be shrunk to nonnull values; however, such information may not be available. We propose a Bayesian semiparametric approach that allows shrinkage to multiple locations. Coefficients are given a mixture of heavy-tailed double exponential priors, with location and scale parameters assigned Dirichlet process hyperpriors to allow groups of coefficients to be shrunk toward the same, possibly nonzero, mean. Our approach favors sparse, but flexible, structure by shrinking toward a small number of random locations. The methods are illustrated using a study of genetic polymorphisms and Parkinson's disease. [source] Shrinkage-based Diagonal Discriminant Analysis and Its Applications in High-Dimensional DataBIOMETRICS, Issue 4 2009Herbert Pang Summary High-dimensional data such as microarrays have brought us new statistical challenges. For example, using a large number of genes to classify samples based on a small number of microarrays remains a difficult problem. Diagonal discriminant analysis, support vector machines, and,k -nearest neighbor have been suggested as among the best methods for small sample size situations, but none was found to be superior to others. In this article, we propose an improved diagonal discriminant approach through shrinkage and regularization of the variances. The performance of our new approach along with the existing methods is studied through simulations and applications to real data. These studies show that the proposed shrinkage-based and regularization diagonal discriminant methods have lower misclassification rates than existing methods in many cases. [source] Interference of MI-D, a new mesoionic compound, on artificial and native membranesCELL BIOCHEMISTRY AND FUNCTION, Issue 1 2002Silvia M.S.C. Cadena Abstract MI-D (4-phenyl-5-(4-nitrocinnamoyl)-1,3,4-thiadiazolium-2-phenylamine chloride), a new mesoionic compound, decreased the rate of swelling induced by valinomycin-K+, as well as induced swelling in the presence of nigericin-K+. Shrinkage was also affected, suggesting interference with the inner mitochondrial membrane, which would affect both fluidity and elasticity. Fluorescence polarization of DPH and DPH-PA, probing the core and outer regions respectively, of the DMPC and native membranes, indicated that MI-D shifts the midpoint of phase transition to higher values and orders of the fluid phase. These alterations in membrane fluidity are thus related to MI-D effects on the energy-linked functions of mitochondria. Copyright © 2001 John Wiley & Sons, Ltd. [source] Inorganic Precipitated Silica Gel.CHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 6 2010Gel Properties, Part 1: Gelation Kinetics Abstract Precipitated silica (SiO2) is industrially produced by mixing a silicate solution with acid in a semi-batch process. Polycondensation of monomeric silica leads to the formation of particles which aggregate and eventually form a particulate gel. However, this is instantly fragmented by the mechanical energy input caused by the stirrer. Shrinkage and compaction of these fragments lead to the final product aggregates. It is the aim of this study to enable tailoring of the structure and size of these product particles via the process parameters. The present paper describes the influence of the parameters temperature, ionic strength, and composition, which affect the pH, on the properties of unstirred gels regarding their elasticity and thus their fragmentation behavior. Gelation time may be qualitatively estimated solely from the concentration of the feed materials. [source] The Pathophysiology of ,Brain Shrinkage' in Alcoholics , Structural and Molecular Changes and Clinical ImplicationsALCOHOLISM, Issue 6 2005Clive Harper This article represents a symposium of the 2004 ISBRA Congress held in Mannheim. The presentations were: Review of the neuropathological and neurochemical changes seen in alcohol-related ,brain shrinkage' by Clive Harper; In Vivo Detection of Macrostructural and Microstructural Markers of Brain Integrity in Human Alcoholism and a Rodent Model of Alcoholism by Adolf Pfefferbaum, Elfar Adalsteinsson and Edith Sullivan; Gene and Protein Changes in the Brains of Alcoholics with ,Brain Shrinkage' by Joanne Lewohl and Peter Dodd; Cross sectional and longitudinal MR spectroscopy studies of chronic adult alcoholics by Michael Taylor; Brain Atrophy Associated with Impairment on a Simulated Gambling Task in Long-Term Abstinent Alcoholics by George Fein and Bennett Landman. [source] Anisotropic contraction in forisomes: Simple models won't fitCYTOSKELETON, Issue 5 2008Winfried S. Peters Abstract Forisomes are ATP-independent, Ca2+ -driven contractile protein bodies acting as reversible valves in the phloem of plants of the legume family. Forisome contraction is anisotropic, as shrinkage in length is associated with radial expansion and vice versa. To test the hypothesis that changes in length and width are causally related, we monitored Ca2+ - and pH-dependent deformations in the exceptionally large forisomes of Canavalia gladiata by high-speed photography, and computed time-courses of derived geometric parameters (including volume and surface area). Soybean forisomes, which in the resting state resemble those of Canavalia geometrically but have less than 2% of the volume, were also studied to identify size effects. Calcium induced sixfold volume increases in forisomes of both species; in soybean, responses were completed in 0.15 s, compared to about 0.5 s required for a rapid response in Canavalia followed by slow swelling for several minutes. This size-dependent behavior supports the idea that forisome contractility might rest on similar mechanisms as those of polyelectrolyte gels, a class of artificial "smart" materials. In both species, time-courses of forisome length and diameter were variable and lacked correlation, arguing against a simple causal relationship between changes in length and width. Moreover, changes in the geometry of soybean forisomes differed qualitatively between Ca2+ - and pH-responses, suggesting that divalent cations and protons target different sites on the forisome proteins. Cell Motil. Cytoskeleton 2008. © 2008 Wiley-Liss, Inc. [source] Comparison of Endovenous Radiofrequency Versus 810 nm Diode Laser Occlusion of Large Veins in an Animal ModelDERMATOLOGIC SURGERY, Issue 1 2002Robert A. Weiss MDArticle first published online: 27 FEB 200 background. Endovenous occlusion using radiofrequency (RF) energy has been shown to be effective for the elimination of sapheno-femoral reflux and subsequent elimination of varicose veins. Recently, endovenous laser occlusion has been introduced with initial clinical reports indicating effective treatment for varicose veins. However, in our practice we note increased peri-operative hematoma and tenderness with the laser. Little is known regarding the mechanism of action of this new laser vein therapy. objective. To better understand the mechanism of action of endovenous laser vs. the endovenous RF procedure in the jugular vein of the goat model. methods. A bilateral comparison was performed using 810 nm diode laser transmitted by a bare-tipped optical fiber vs. the RF delivery by engineered electrodes with a temperature feedback loop using a thermocouple (Closure procedure) in three goat jugular veins. Immediate and one-week results were studied radiographically and histologically. Temperature measurements during laser treatment were performed by using an array of up to five thermocouples, spaced 2 mm apart, placed adjacent to a laser fiber tip during goat jugular vein treatment. results. Immediate findings showed that 100% of the laser-treated veins showed perforations by histologic examination and immediate contrast fluoroscopy. The RF-treated side showed immediate constriction with maintenance of contrast material within the vein lumen and no perforations. The difference in acute vein shrinkage was also dramatic as laser treatments resulted in vein shrinkage of 26%, while RF-treated veins showed a 77% acute reduction in diameter. At one week, extravasated blood that leaked into the surrounding tissue of laser treated veins acutely, continued to occupy space and impinge on surrounding structures including nerves. For the laser treatment, the highest average temperature was 729°C (peak temperature 1334°C) observed flush with the laser fiber tip, while the temperature feedback mechanism of the RF method maintains temperatures at the electrodes of 85°C. conclusion. Vein perforations, extremely high intravascular temperatures, failure to cause significant collagen shrinkage, and intact endothelium in an animal model justify a closer look at the human clinical application of the 810 nm endovenous laser technique. Extravasated blood impinging on adjacent structures may theoretically lead to increased peri-operative hematoma and tenderness. Further study and clinical investigation is warranted. [source] | |||||||||||||||||||||||||||||||||||||||||||||||||