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Breakthrough
Kinds of Breakthrough Terms modified by Breakthrough Selected AbstractsBREAKTHROUGH FOR RURAL DOCTORSAUSTRALIAN JOURNAL OF RURAL HEALTH, Issue 1 2003Article first published online: 28 JUN 200 No abstract is available for this article. [source] Can Contaminant Transport Models Predict Breakthrough?GROUND WATER MONITORING & REMEDIATION, Issue 4 2000Wei-Shyuan "Stone" Peng A solute breakthrough curve measured during a two-well tracer test was successfully predicted in 1986 using specialized contaminant transport models. Water was injected into a confined, unconsolidated sand aquifer and pumped out 125 feet (38.3 m) away at the same steady rate. The injected water was spiked with bromide for over three days; the outflow concentration was monitored for a month. Based on previous tests, the horizontal hydraulic conductivity of the thick aquifer varied by a factor of seven among 12 layers. Assuming stratified flow with small dispersivities, two research groups accurately predicted breakthrough with three-dimensional (12-layer) models using curvilinear elements following the arc-shaped flowlines in this test. Can contaminant transport models commonly used in industry, that use rectangular blocks, also reproduce this breakthrough curve? The two-well test was simulated with four MODFLOW-based models, MT3D (FD and HMOC options), MODFLOWT, MOC3D, and MODFLOW-SURFACT. Using the same 12 layers and small dispersivity used in the successful 1986 simulations, these models fit almost as accurately as the models using curvilinear blocks. Subtle variations in the curves illustrate differences among the codes. Sensitivities of the results to number and size of grid blocks, number of layers, boundary conditions, and values of dispersivity and porosity are briefly presented. The fit between calculated and measured breakthrough curves degenerated as the number of layers and/or grid blocks decreased, reflecting a loss of model predictive power as the level of characterization lessened. Therefore, the breakthrough curve for most field sites can be predicted only qualitatively due to limited characterization of the hydrogeology and contaminant source strength. [source] Hepatitis B virus variants in patients receiving lamivudine treatment with breakthrough hepatitis evaluated by serial viral loads and full-length viral sequencesHEPATOLOGY, Issue 3 2001Chun-Jen Liu Both viral loads and genome variations have been implicated in the pathogenesis of acute exacerbation of chronic hepatitis B. Hepatitis B exacerbation in patients receiving lamivudine treatment represented a unique setting to clarify their importance. Three organ recipients with posttransplantation hepatitis B exacerbation and 3 patients with chronic hepatitis B were studied. All received lamivudine treatment and their alanine aminotransferase (ALT) levels and hepatitis B virus (HBV) loads were regularly followed. Full-length genomic sequences before and during lamivudine treatment were determined in patients who had breakthrough of serum HBV DNA or elevation of serum ALT. Breakthrough of serum HBV DNA occurred after 6 to 15 months of lamivudine treatment in all. A rapid increase of viral load accompanying the emergence of tyrosine-methionine-aspartate-aspartate (YMDD) variant was followed by hepatitis B exacerbation in each patient. The mean number of nucleotide and amino acid substitutions per genome pair was equivalent in immunosuppressed or immunocompetent patients (6.3 vs. 6.3 for nucleotide, P > .05; 6.0 vs. 6.7 for amino acid, P > .05). Changes of nucleotide and amino acid beyond the YMDD motif were distributed along the whole HBV genome but none occurred within the known B-cell epitopes and human leukocyte antigen class I, or II,restricted T-cell epitopes. Our results suggest that a resurgence of viral load rather than changes of the known immunogenic viral epitopes is more closely associated with the development of hepatitis B exacerbation after the emergence of YMDD variants in patients receiving lamivudine treatment. (HEPATOLOGY 2001;34:583-589.) [source] The Lutheran-Catholic Agreement on Justification: Botch or Breakthrough?NEW BLACKFRIARS, Issue 967 2001Aidan Nichols OP First page of article [source] Joseph M. Juran, a perspective on past contributions and future impactQUALITY AND RELIABILITY ENGINEERING INTERNATIONAL, Issue 6 2007A. Blanton Godfrey Abstract This paper combines presentations by the authors in a special session dedicated to the work of Joseph M. Juran at the sixth annual conference of the European Network for Business and Industrial Statistics in Wroclaw, Poland. The paper offers an historical perspective of the contributions of J. M. Juran to management science emphasizing aspects of cause and effect relationships and Integrated Models. Specifically, the paper presents the Juran concepts of Management Breakthrough, the Pareto Principle, the Juran Trilogy® and Six Sigma. The impact of these contributions, put in an historical perspective of key thinkers who investigated cause and effect relationships, is then discussed. The impact of these contributions to modern Integrated Models is then assessed. Copyright © 2007 John Wiley & Sons, Ltd. [source] Impact of Virologic Breakthrough and HBIG Regimen on Hepatitis B Recurrence After Liver TransplantationAMERICAN JOURNAL OF TRANSPLANTATION, Issue 8 2010B. Degertekin The availability of hepatitis B immune globulin (HBIG) and several oral antiviral therapies has reduced but not eliminated hepatitis B virus (HBV) recurrence. We aimed to determine the rate of HBV recurrence after orthotopic liver transplantation (OLT) in relation to virologic breakthrough pre-OLT and HBIG regimens post-OLT. Data from the NIH HBV-OLT database were analyzed. A total of 183 patients transplanted between 2001 and 2007 followed for a median of 42 months (range 1,81) post-OLT were studied. At transplant, 29% were hepatitis B e antigen (HBeAg) (+), 38.5% had HBV DNA > 5 log10 copies/mL, 74% were receiving antiviral therapy. Twenty-five patients experienced virologic breakthrough before OLT. Post-OLT, 26%, 22%, 40% and 12% of patients received intravenous (IV) high-dose, IV low-dose, intramuscular low-dose and a finite duration of HBIG, respectively as maintenance prophylaxis. All but two patients also received antiviral therapy. Cumulative rates of HBV recurrence at 1 and 5 years were 3% and 9%, respectively. Multivariate analysis showed that listing HBeAg status and HBV DNA level at OLT were the only factors associated with HBV recurrence. In conclusion, low rates of HBV recurrence can be accomplished with all the HBIG regimens used when combined with antiviral therapy including patients with breakthrough pre-OLT as long as rescue therapy is administered pre- and post-OLT. [source] Combination antibiotics for Chlamydia -induced arthritis: Breakthrough to a cure?ARTHRITIS & RHEUMATISM, Issue 5 2010Markus Rihl First page of article [source] G.B. Elion (1918,1999) and G.H. Hitchings (1905,1998): Breakthrough in the treatment of childhood leukaemiaACTA PAEDIATRICA, Issue 8 2006Rolf Zetterström No abstract is available for this article. [source] The Global Health and Diagnostic (Flow) Cytometry,Breakthroughs in HIV and Tuberculosis,,CYTOMETRY, Issue S1 2008Michael Merson No abstract is available for this article. [source] Screening for Novel Industrial BiocatalystsENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 6 2004P. Lorenz Abstract Biocatalysis, the use of microbial cells or isolated enzymes in the production of fine chemicals, is steadily moving towards becoming accepted as an indispensable tool in the inventory of modern synthetic chemistry [1]. It is estimated that in 10,% of the cases biocatalysis will provide an overall superior synthetic strategy over traditional organic chemistry [2]. This remarkable development in a field coined "white biotechnology" is due to the growing recognition in the industry of the capabilities and performance of enzymes as exemplified in a growing number of implemented processes [3,,4], examples running at a scale of >1000 tons product/year. Breakthroughs in the key biotechnological areas of a) genetic resource access (explicitly the explorability of non-cultivated microorganisms), b) enzyme screening and discovery and c) in vitro evolution of proteins to find and optimize enzymes to become near-ideally suited biocatalysts have been instrumental in pushing industrial biocatalysis to where it stands today [5, 6]. With these technological options it seems that future use of biocatalysis is limited only by the availability of the biocatalyst [3], the screening for which is subject of this review. [source] Cover Picture , Breakthroughs in ImmunologyEUROPEAN JOURNAL OF IMMUNOLOGY, Issue S1 2007Article first published online: 31 OCT 200 No Abstracts [source] The Joint Research Program "CPR Precipitation" , Breakthroughs in the Understanding of Kinetic Pathways for the Early Stages of Phase Separation,ADVANCED ENGINEERING MATERIALS, Issue 12 2006G. Martin The CNRS joint research program, "CPR Precipitation", has been carefully prepared by the industrial initiators. Very significant results were obtained: they are summarized in the following and presented in this meeting. As for the future, the CPR has catalyzed the formation of a community of promising scientific interest: it would be of common benefit to stabilize this community by an appropriate further support. [source] Effect of chemical heterogeneity on adsorbed solute dispersion at column scaleAICHE JOURNAL, Issue 4 2008Safia Semra Abstract Chemical heterogeneity seems to be responsible for spreading increase of adsorbed solute breakthrough curves. Adsorption in fixed beds assumes chemically homogeneous media. However, this is not always true, in particular when natural sands or mixed adsorbent filters are used in drinking water purification. Neglecting eventual effect of chemical heterogeneity may engender false modeling bases. So, considering homogeneous grain size distribution, the effect of chemical heterogeneity on global dispersion in porous media has been investigated experimentally in this article at column scale. Breakthroughs of adsorbed solute showed a visible effect of chemical heterogeneity on solute global dispersion increasing. The more heterogeneous the medium, the more spread the adsorbed solute breakthrough. Reduced variance showed a linear variation with the chemical heterogeneity scale at closely constant media global capacity. A pseudo-homogeneous model has been developed to simulate experimental data by increasing dispersion parameter. © 2008 American Institute of Chemical Engineers AIChE J, 2008 [source] Breakthroughs in Hydrogen Storage,Formic Acid as a Sustainable Storage Material for HydrogenCHEMSUSCHEM CHEMISTRY AND SUSTAINABILITY, ENERGY & MATERIALS, Issue 10 2008Ferenc Joó Prof. A boost for fuel cells: Recent results suggest that formic acid is a convenient hydrogen-storage material: its decomposition yields CO-free hydrogen while the co-produced carbon dioxide can be hydrogenated back to formic acid. The hydrogen generated in this way is suitable for fuel cell applications. [source] Advances in insect biotechnology for human welfareENTOMOLOGICAL RESEARCH, Issue 2008Thomas A. MILLER Abstract Biotechnology is the latest scientific breakthrough in the history of agriculture. Yet despite the promise of developing new tools for pest and disease control, transgenic organisms have encountered a mixed reception by the lay and scientific public alike. Yields are unable to keep pace with rising costs resulting in a decline in traditional farming. Switching to a new organic growing paradigm is occurring in Korea and the United States today. These new approaches ignore traditional tools that were responsible for the increased yields that support the current affluence and allowed us to protect crops while buying time to find more ecologically-friendly methods. The perception that we understand crop diseases and pests is false and those making this assumption risk destabilizing global food production. There are new pests and diseases that are very difficult to control without these traditional non-organic methods. Invasive species continue to arrive at high rates adding to the burden of farming. Global climate change is already causing changes in the pest and disease complexes and is forcing the entomologist and plant pathologist to make drastic changes to adjust to them. [source] Perspectives of multi-modal contribution of honeybee resources to our lifeENTOMOLOGICAL RESEARCH, Issue 2008Hidehiro HOSHIBA Abstract The European honeybee, Apis mellifera, has been introduced to all continents and their products like honey, propolis, royal jelly and beeswax are well known. However, its contribution is not restricted to such direct products but extends into a much wider area. For example, the economic value of seed production by pollination exceeds the above-mentioned bee products. The application of F1 hybrid is increased to as much as 70% of commercial crops and flowers in Japan and honeybees are important pollinators in the F1 seed production. Incorporation into the large-scale biodiesel fuel production system by culturing rape and sunflower seeds etc. is relied on because it is good to construct possible zero-emission systems that reduce carbon dioxide and increase the rich by-products like honey and royal jelly. Bees' higher brain function and sophisticated social system of the colony opens new perspectives as a model system. Their individual ability to recognize even abstract concepts is comparable to that of higher primates. Rats or mice have no such ability. High performance learning ability of bees associated with proboscis extension reflex can be used to detect drugs at the airport. Function of the colony, on the other hand, is an excellent model for social physiology or a self-organization system. After the whole genome of A. mellifera was read in 2006 by the world consortium, consisting of more than 90 institutions from all over the world, many molecular biologists are coming into bee world. Nobody has yet succeeded in the challenge to make transgenic honeybee, so far, because of the difficulty in controlling the reproductive system headed by the queen. However, if someone succeeded in a breakthrough we will have stingless honeybees and a disease-resistant strain in the future. [source] Improved methods for carbon adsorption studies for water and wastewater treatmentENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 2 2006Wei-chi Ying Abstract An improved method was developed to rank activated carbon in removing organic water pollutants. The simple and standardized evaluation method uses a set of four adsorptive capacity indicators: phenol, iodine, methylene blue, and tannic acid numbers; those four indicator compounds were selected because they cover the molecular size range of most organic water pollutants. An improved microcolumn rapid breakthrough (MCRB) test method was developed from the existing HPMC (high-pressure minicolumn) and RSSCT (rapid small-scale column test) methods by simplifying the experimental procedure and using readily available low-cost pump, sampler, piping, and fittings. This method can be practiced in an ordinary environmental laboratory to select the best carbon, to verify the treatment effectiveness, and to estimate the adsorption treatment cost based on the observed capacity utilization rate for carbon in the adsorber without the problems often encountered with using small and mini traditional columns. The benefits of the four-parameter carbon selection method and the MCRB method were demonstrated by adsorption isotherm and breakthrough data for several indicator compounds and organic water pollutants. These improved methods will enable efficient carbon adsorption studies necessary for more applications of carbon adsorption technology in water and wastewater treatment. © 2006 American Institute of Chemical Engineers Environ Prog, 2006 [source] The Art and Science of Tailoring Materials by Nanostructuring for Advanced Properties Using SPD Techniques,ADVANCED ENGINEERING MATERIALS, Issue 8 2010Ruslan Z. Valiev In recent years a breakthrough has developed in the studies of nanostructured metals and alloys as advanced structural and functional materials associated both with the development of new routes for the fabrication of bulk nanostructured materials using severe plastic deformation (SPD) and with investigations of the fundamental mechanisms that lead to the new properties of these materials. This review paper discusses new concepts and principles in using SPD processing to fabricate bulk nanostructured metals with advanced properties. Special emphasis is placed on the relationship between microstructural features and properties, as well as the innovation potential of SPD-produced nanomaterials. [source] Is extreme right-wing populism contagious?EUROPEAN JOURNAL OF POLITICAL RESEARCH, Issue 3 2005Explaining the emergence of a new party family As the old master frame of the extreme right was rendered impotent by the outcome of the Second World War, it took the innovation of a new, potent master frame before the extreme right was able to break electoral marginalization. Such a master frame , combining ethnonationalist xenophobia, based on the doctrine of ethnopluralism, with anti-political-establishment populism , evolved in the 1970s, and was made known as a successful frame in connection with the electoral breakthrough of the French Front National in 1984. This event started a process of cross-national diffusion, where embryonic extreme right-wing groups and networks elsewhere adopted the new frame. Hence, the emergence of similar parties, clustered in time (i.e., the birth of a new party family) had less to do with structural factors influencing different political systems in similar ways as with cross-national diffusion of frames. The innovation and diffusion of the new master frame was a necessary, but not a sufficient, condition for the emergence of extreme right-wing populist parties. In order to complete the model, a short list of different political opportunity structures is added. [source] The inherent ,safety-net' of an Acrisol: measuring and modelling retarded leaching of mineral nitrogenEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 2 2002D. Suprayogo Summary The inherent features of Acrisols with their increasing clay content with depth are conducive to reducing nutrient losses by nutrient adsorption on the matrix soil surfaces. Ammonium (NH4+) and nitrate (NO3,) adsorption by a Plinthic Acrisol from Lampung, Indonesia was studied in column experiments. The peak of the H218O breakthrough occurred at 1 pore volume, whereas the median pore volumes for NH4+ and NO3, ranged from 6.4 to 6.9 and 1.1 to 1.6, respectively. The adsorption coefficients (Ka in cm3 g,1) measured were 1.81, 1.51, 1.64 and 1.47 for NH4+ and 0.03, 0.09, 0.10 and 0.17 for NO3,, respectively, in the 0,0.2, 0.2,0.4, 0.4,0.6 and 0.6,0.8 m soil depth layers. The NH4+ and NO3, adsorption coefficients derived from this study were put in to the Water, Nutrient and Light Capture in Agroforestry Systems (WaNuLCAS) model to evaluate their effect on leaching in the context of several cropping systems in the humid tropics. The resulting simulations indicate that the inherent ,safety-net' (retardation mechanism) of a shallow (0.8,1 m) Plinthic Acrisol can reduce the leaching of mineral N by between 5 and 33% (or up to 2.1 g m,2), mainly due to the NH4+ retardation factor, and that the effectiveness in reducing N leaching increases with increasing depth. However, the inherent ,safety-net' is useful only if deep-rooted plants can recover the N subsequently. [source] Pedotransfer functions for solute transport parameters of Portuguese soilsEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 4 2001M. C. Gonc, alves Summary The purpose of this study is to quantify solute transport parameters of fine-textured soils in an irrigation district in southern Portugal and to investigate their prediction from basic soil properties and unsaturated hydraulic parameters. Solute displacement experiments were carried out on 24 undisturbed soil samples by applying a 0.05 m KCl pulse during steady flow. The chloride breakthrough curves (BTCs) were asymmetric, with early breakthrough and considerable tailing characteristic of non-equilibrium transport. The retardation factor (R), dispersion coefficient (D), partitioning coefficient (,), and mass transfer coefficient (,) were estimated by optimizing the solution of the non-equilibrium convection,dispersion equation (CDE) to the breakthrough data. The solution could adequately describe the observed data as proved by a median of 0.972 for the coefficient of determination (r2) and a median for the mean squared error (MSE) of 5.1 × 10,6. The median value for R of 0.587 suggests that Cl, was excluded from a substantial part of the liquid phase. The value for , was typically less than 0.5, but the non-equilibrium effects were mitigated by a large mass transfer coefficient (, > 1). Pedotransfer functions (PTFs) were developed with regression and neural network analyses to predict R, D, , and , from basic soil properties and unsaturated hydraulic parameters. Fairly accurate predictions could be obtained for logD (r2 , 0.9) and , (r2 , 0.8). Prediction for R and log, were relatively poor (r2 , 0.5). The artificial neural networks were all somewhat more accurate than the regression equations. The networks are also more suitable for predicting transport parameters because they require only three input variables, whereas the regression equations contain many predictor variables. [source] Single- and dual-porosity modelling of multiple tracer transport through soil columns: effects of initial moisture and mode of applicationEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 1 2001T. Kätterer Summary We investigated the effect of initial moisture contents and mode of application on the displacement of multiple conservative tracers through undisturbed columns of a Humic Gleysol. Bromide was applied at the soil surface and chloride was injected at 5 cm depth. The columns were irrigated with deuterium-enriched water. A dual-porosity model and two single-porosity models were calibrated separately to Br, and Cl, elution curves in the two columns. Elution curves were almost identical for Br, and Cl, under initially wet conditions, whereas the displacement of Br, was faster than that of Cl, in the initially dry column, indicating rapid transport with preferential flow. Only the dual-porosity model described the long-tailing breakthrough of Cl, in the initially dry column adequately. The parameter values giving acceptable fits for ,Br dry' were not compatible with the description of the three other elution curves, which could be adequately modelled with a single set of parameter values. The estimated set of common parameters was validated by comparing with the elution curves of deuterium water, nitrate and sulphate, as well as with resident tracer concentrations at four depths. The results showed that solutes can be displaced much faster when applied at the surface of initially dry soil than when applied to wet soil or when resident in the soil matrix. The simulation results suggest that solute transport under initially dry conditions was governed by preferential flow of infiltration water through macropores by-passing the matrix due to shrinkage cracks and water repellence of matrix surfaces. [source] The soft-output principle,reminiscences and new developments,EUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 8 2007Peter A. Hoeher A major breakthrough in digital communications was the provisioning of ,soft' outputs at each processing stage, with appropriate capabilities to use this as soft inputs in the next processing stage. This allowed for much more performant receivers especially in difficult mobile radio channel conditions, and set the stage for iterative processing. This article will outline the development of soft output algorithms over the last two decades along with associated state-of-the-art applications and conclude with an outlook towards novel applications of the soft principle. Copyright © 2007 John Wiley & Sons, Ltd. [source] Tailoring Hydrogen Storage Materials Towards ApplicationADVANCED ENGINEERING MATERIALS, Issue 5 2006M. Dornheim Abstract A breakthrough in hydrogen storage technology was achieved by preparing nanocrystalline hydrides using high-energy ball milling and the use of suitable catalysts/additives. These new materials show fast or in case of Mg-based hydrides very fast absorption and desorption kinetics within minutes, thus qualifying lightweight Mg- or Al-based hydrides for storage applications. This article summarizes our current understanding of the kinetics of Mg-based light metal hydrides, describes an approach for a cost-effective processing technology and highlights some promising new developments in lightweight metal hydride research. [source] Serum-free cultured keratinocytes fail to organize fibronectin matrix and possess different distribution of beta-1 integrinsEXPERIMENTAL DERMATOLOGY, Issue 2 2001G. Altankov Abstract: The development of serum free medium formulation for culturing keratinocytes was a breakthrough in achieving a high number of epidermal cells for experimental and therapeutic studies, in particular to support the wound healing process. It is not clear, however, if switching the cells to highly proliferative phenotype may reflect change in other cellular functions important for the wound repair as their adhesive interactions with the extracellular matrix components. Remodelling of the extracellular matrix, particularly of fibronectin plays an essential role for guiding the cells during wound healing. The molecular mechanisms for organization of this provisional fibronectin matrix, however, are still not clear. We found that keratinocytes in serum containing medium, although in fewer numbers than fibroblasts, were able to remove adsorbed fluorescent labelled fibronectin from the substratum and reorganize it in a fibrilar pattern along the cell periphery. After 3 days the secreted fibronectin had also been organized as matrix-like fibers and as clusters deposited on the substratum after migrating cells. In contrast, serum free cultured keratinocytes fail to organize pre-adsorbed fluorescent labelled fibronectin, as well as the secreted fibronectin, although they grow very well under these conditions. Switching the cells to serum containing medium initiates the removal of fluorescent labelled fibronectin from the substratum, however without reorganization in fibrillar pattern. Most likely, these keratinocytes remove fluorescent labelled fibronectin by the expression of proteolytic activity, rather than with the mechanical function of ,1 integrins. The latter were diffusely dispersed in serum containing conditions and tend to organize in focal adhesions in serum free cultured cells. We assumed their transient expression and different affinity state might be important for the keratinocyte migration and matrix assembly mechanism. [source] Magnesium sulphate treatment decreases blood,brain barrier permeability during acute hypertension in pregnant ratsEXPERIMENTAL PHYSIOLOGY, Issue 2 2008Anna G. Euser Eclampsia is associated with increased blood,brain barrier (BBB) permeability and formation of cerebral oedema. Magnesium sulphate is used to treat eclampsia despite an unclear mechanism of action. This study was to determine the effect of magnesium sulphate on in vivo BBB permeability and formation of cerebral oedema during acute hypertension and on brain aquaporin-4 (AQP4) protein expression. An in vivo model of hypertensive encephalopathy was used in late-pregnant (LP) rats following magnesium sulphate treatment, 270 mg kg,1i.p. injection every 4 h for 24 h. Permeability of the BBB was determined by in situ brain perfusion of Evan's Blue (EB) and sodium fluorescein (NaFl), and dye clearance determined by fluorescence spectrophotometry. Cerebral oedema was determined following acute hypertension by measuring brain water content. The effect of magnesium treatment on AQP4 expression was determined by Western blot analysis. Acute hypertension with autoregulatory breakthrough increased BBB permeability to EB in both brain regions studied (P < 0.05). Magnesium attenuated BBB permeability to EB during acute hypertension by 41% in the posterior cerebrum (P < 0.05) but had no effect in the anterior cerebrum (P > 0.05). Treatment with magnesium did not change NaFl permeability, cerebral oedema formation or AQP4 expression. In summary, BBB permeability to Evan's Blue was increased by acute hypertension in LP rats, and this was attenuated by treatment with magnesium sulphate. The greatest effect on BBB permeability to EB was in the posterior cerebrum, an area particularly susceptible to oedema formation during eclampsia. [source] Outstanding Ceramic Matrix Composites for High Temperature ApplicationsADVANCED ENGINEERING MATERIALS, Issue 3 2005L. Vandenbulcke Accurate deposition of boron and silicon carbides and nitrides permits to improve the oxidation resistance of self-healing matrices of multilayered composites. The uniformity and the microstructure of each layer and of their interfaces induce the final properties of these composites. Their mechanical behaviour in conditions very close to the applications in the energy, space and aeronautic domains, allows to demonstrate the breakthrough enabled by this new composite generation. [source] Porous Silicon-Based Optical Microsensors for Volatile Organic Analytes: Effect of Surface Chemistry on Stability and SpecificityADVANCED FUNCTIONAL MATERIALS, Issue 17 2010Anne M. Ruminski Abstract Sensing of the volatile organic compounds (VOCs) isopropyl alcohol (IPA) and heptane in air using sub-millimeter porous silicon-based sensor elements is demonstrated in the concentration range 50,800 ppm. The sensor elements are prepared as one-dimensional photonic crystals (rugate filters) by programmed electrochemical etch of p++ silicon, and analyte sensing is achieved by measurement of the wavelength shift of the photonic resonance. The sensors are studied as a function of surface chemistry: ozone oxidation, thermal oxidation, hydrosilylation (1-dodecene), electrochemical methylation, reaction with dicholorodimethylsilane and thermal carbonization with acetylene. The thermally oxidized and the dichlorodimethylsilane-modified materials show the greatest stability under atmospheric conditions. Optical microsensors are prepared by attachment of the porous Si layer to the distal end of optical fibers. The acetylated porous Si microsensor displays a greater response to heptane than to IPA, whereas the other chemical modifications display a greater response to IPA than to heptane. The thermal oxide sensor displays a strong response to water vapor, while the acetylated material shows a relatively weak response. The results suggest that a combination of optical fiber sensors with different surface chemistries can be used to classify VOC analytes. Application of the miniature sensors to the detection of VOC breakthrough in a full-scale activated carbon respirator cartridge simulator is demonstrated. [source] Simultaneous Immobilization of Bioactives During 3D Powder Printing of Bioceramic Drug-Release MatricesADVANCED FUNCTIONAL MATERIALS, Issue 10 2010Elke Vorndran Abstract The combination of a degradable bioceramic scaffold and a drug-delivery system in a single low temperature fabrication step is attractive for the reconstruction of bone defects. The production of calcium phosphate scaffolds by a multijet 3D printing system enables localized deposition of biologically active drugs and proteins with a spatial resolution of approximately 300,µm. In addition, homogeneous or localized polymer incorporation during printing with HPMC or chitosan hydrochloride allows the drug release kinetics to be retarded from first to zero order over a period of 3,4 days with release rates in the range 0.68%,0.96%,h,1. The reduction in biological activity of vancomycin, heparin, and rhBMP-2 following spraying through the ink jet nozzles is between 1% and 18%. For vancomycin, a further loss of biological activity following incorporation into a cement and subsequent in vitro release is 11%. While previously acknowledged as theoretically feasible, is its shown for the first time that bone grafts with simultaneous geometry, localized organic bioactive loading, and localized diffusion control are a physical reality. This breakthrough offers a new future for patients by providing the required material function to match patient bone health status, site of repair, and age. [source] Functional interaction of general transcription initiation factor TFIIE with general chromatin factor SPT16/CDC68GENES TO CELLS, Issue 4 2000Seung-Woo Kang Background Transcriptional initiation of class II genes is one of the major targets for the regulation of gene expression and is carried out by RNA polymerase II and many auxiliary factors, which include general transcription initiation factors (GTFs). TFIIE, one of the GTFs, functions at the later stage of transcription initiation. As recent studies indicated the possibility that TFIIE may have a role in chromatin transcriptional regulation, we isolated TFIIE-interacting factors which have chromatin-related functions. Results Using the yeast two-hybrid screening system, we isolated the C-terminal part of the human homologue of Saccharomyces cerevisiae (y) Spt16p/Cdc68p, a general chromatin factor. The C-terminal part of human SPT16/CDC68 directly interacts with TFIIE, and ySpt16p/Cdc68p also interacts with yTFIIE (Tfa1p/Tfa2p), thus indicating the existence of an evolutionarily conserved interaction between TFIIE and SPT16/CDC68. Functional interaction of yTFIIE and ySpt16p/Cdc68p was examined using a conditional yTFIIE-, mutant strain. Over-expression of ySpt16p/Cdc68p suppressed the phenotype of cold sensitivity of the yTFIIE-,- cs mutant strain, and in vitro binding assays revealed that yTFIIE-,- cs mutant protein showed diminished binding affinity to ySpt16p/Cdc68p. Conclusions These observations indicate that general transcription initiation factor TFIIE functionally interacts with general chromatin factor SPT16/CDC68, a finding which provides new insight into the involvement of TFIIE in chromatin transcription. This may well lead to a breakthrough in relationships between the transcription initiation process and structural changes in chromatin. 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