bluuebunny/crossref_metadata_2025_split huggingface dataset:
Direct determination of bentazepam in a biological sample with a sepiolite‐modified carbon paste electrode
Authors: Hernandez L. , Hernandez P. , Lorenzo E. 
Published: February 2006

AbstractCarbon paste electrodes (CPEs) modified with sepiolite are employed for adsorptive accumulation and voltammetric determination of the drug bentazepam. Response variables are explored, and measurements in urine samples are illustrated.
Electroosmotic flow in a rectangular channel with variable wall zeta‐potential: Comparison of numerical simulation with asymptotic theory
Authors: Datta Subhra , Ghosal Sandip , Patankar Neelesh A. 
Published: February 2006

AbstractElectroosmotic flow in a straight micro‐channel of rectangular cross‐section is computed numerically for several situations where the wall zeta‐potential is not constant but has a specified spatial variation. The results of the computation are compared with an earlier published asymptotic theory based on the lubrication approximation: the assumption that any axial variations take place on a long length scale compared to a characteristic channel width. The computational results are found to be in excellent agreement with the theory even when the scale of axial variations is comparable to the channel width. In the opposite limit when the wavelength of fluctuations is much shorter than the channel width, the lubrication theory fails to describe the solution either qualitatively or quantitatively. In this short wave limit the solution is well described by Ajdari's theory for electroosmotic flow between infinite parallel plates (Ajdari, A., Phys. Rev. E 1996, 53, 4996–5005.) The infinitely thin electric double layer limit is assumed in the theory as well as in the simulation.
Capillary electrophoresis for thermodynamic and kinetic studies of peptidyl‐proline isomerization by the theoretical plate height model
Authors: Newman Carl I. D. , McGuffin Victoria L. 
Published: February 2006

AbstractThe theoretical plate height model, extended to include reactive CE, is used to calculate equilibrium constants and rate constants for the reversible, first‐order isomerization of proline dipeptides. This model is consistent with chromatographic theory and enables calculation of equilibrium constants from velocity and calculation of rate constants from plate height. Thermodynamic and kinetic parameters for isomerization of Ala‐Pro and Phe‐Pro are calculated by using the plate height model, and are shown to be in good agreement with literature values. Additionally, the efficacy of the plate height model is compared to ChromWin, an existing simulation method for calculating rate constants from zone profiles. It is shown that ChromWin and the plate height model are complementary methods. ChromWin is best used for calculating rate constants for reactions that are far from steady state, where the zone profiles exhibit plateau formation. On the other hand, the plate height model is best used for calculating rate constants for reactions that are at or near steady state, where the zone profiles exhibit a single zone containing both reacting species.
Modeling environmental influences on the locations of Irish early medieval ringforts
Authors: Legg Robert J. , Taylor David 
Published: February 2006

AbstractFor the past two decades, archaeologists have been constructing predictive archaeological models to determine the occurrence probability of archaeological sites. Here, the technique has been used to explore the environmental factors that may have had an influence on the distribution of ringforts in Ireland. In the Inny River catchment of the Irish midlands, locational information, together with corresponding environmental variables, were assembled in a geographic information system. The analysis showed that ringfort sites have a distinctive locational pattern and cluster on moderately fertile, well‐drained soils on gently sloping land surfaces (slopes of 4–9%) between 80 and 150 m above mean sea level. To test the practical applicability of the model, the results were extended to two separate areas adjoining the Inny River catchment (Blackwater valley and Lough Ramor catchment) in the form of a probability surface. The model predicts relatively low densities of ringforts in the Blackwater valley and much higher probabilities of occurrence in the Lough Ramor catchment. These predictions are broadly consistent with recorded site distributions. © 2006 Wiley Periodicals, Inc.
Modified calculations of hydrocarbon thermodynamic properties
Authors: Liu Min Hsien , Chen Cheng 
Published: February 2006

AbstractA test set of 65 hydrocarbons was examined to elucidate theoretically their thermodynamic properties by performing the density‐functional theory (DFT) and ab initio calculations. All the calculated data were modified using a three‐parameter calibration equation and the least‐squares approach, to determine accurately enthalpies of formation (ΔHf), entropies (S), and heat capacities (Cp). Calculation results demonstrated that the atomization energies of all compounds exhibited an average absolute relative error ranging between 0.11– 0.13%, and an ΔHf of formation with a mean absolute absolute error (M.|A.E.|) ranging from only 5.7–6.8 kJ/mol (1.3–1.6 kcal/mol) (i.e., those results correlated with those of Dr. Herndon's 1.1 kcal/mol). Additionally, the entropy ranged from 3.5–4.2 J/mol K (0.8–1.0 cal/mol K) M.|A.E.|; a heat capacity between 2.3–2.9 J/mol K (0.5–0.7 cal/mol K) M.|A.E.| was obtained as well. © 2006 Wiley Periodicals, Inc. J Comput Chem 27: 537–544, 2006
In vivo serial diffusion tensor imaging of experimental spinal cord injury
Authors: Deo Aparna A. , Grill Raymond J. , Hasan Khader M. , Narayana Ponnada A. 
Published: February 2006

AbstractIn vivo longitudinal diffusion tensor imaging (DTI) of rodent spinal cord injury (SCI) was carried out over a period of eight weeks post‐injury. A balanced, rotationally invariant, alternating gradient polarity icosahedral diffusion encoding scheme was used for an unbiased estimation of the DTI metrics. The fractional anisotropy (FA), diffusivities along (longitudinal), and perpendicular (transverse) to the fiber tracts, were estimated for the ventral, dorsal, and lateral white matter. In all the three regions, the DTI metrics were observed to be significantly different in injured cords relative to the uninjured controls close to the epicenter of the injury. However, these differences gradually disappeared away from the epicenter. The spatio‐temporal changes in the DTI metrics showed a recovery pattern that is region specific. Although the temporal trends in the tissue recovery in rostral and caudal sections seem to be similar, overall the DTI metrics were observed to be closer to the normal tissue values in the caudal relative to the rostral sections (rostral–caudal asymmetry). © 2006 Wiley‐Liss, Inc.
Open brain gene product Rab23: Expression pattern in the adult mouse brain and functional characterization
Authors: Guo Anchen , Wang Ting , Ng Ee Ling , Aulia Selina , Chong Kooi Hoong , Teng Felicia Yu Hsuan , Wang Ya , Tang Bor Luen 
Published: February 2006

AbstractThe gene mutated in the mouse open brain (opb) phenotype antagonizes sonic hedgehog‐mediated signaling and encodes a small GTPase of the Rab family, Rab23. To date, the brain expression profile and exact mechanism of function of the Rab23 protein has remained unknown. Specific antibodies generated against Rab23 showed that the protein is highly enriched in the adult rodent brain and present in low levels in multiple tissues of the adult rodent. Rab23 is found in the cytosol as well as being associated with the plasma and endosomal membranes. In the adult mouse brain, Rab23 is found in βIII tubulin (TuJ) positive neuronal cell bodies and are most prominent in the cortex, hypothalamus and the cerebellum. It is, however, absent from glial fibrillary acidic protein (GFAP) positive astrocytes or CNPase positive oligodendrocytes. Despite the plasma membrane/endosomal membrane localization of Rab23, neither overexpression of the GTP‐restricted nor the GDP‐bound mutant forms affect internalization of transferrin or epidermal growth factor. Exogenous overexpression of Rab23 or its mutants also did not affect the morphological differentiation of thalamic neurons in culture. Expression of Rab23 in the adult brain is suggestive, however, of having a postnatal function beyond its role in embryonic development. © 2006 Wiley‐Liss, Inc.
Pharmacological and molecular properties of opioid binding sites synthesized in a cell‐free translation system
Authors: Cabon F. , Cupo A. , Ruiz‐Gayo M. , Baumann N. A. , Zalc B. 
Published: February 2006

AbstractCell‐free translation of mRNA, extracted from NG108‐15 cells, was used to examine some properties of the opioid binding sites synthesized in vitro. A monoclonal antiidiotype antibody directed against the δ opioid receptor immunoprecipitated a major band of Mr 51,000. Translational immunoassays of poly‐[A]+RNA, size fractionated by methylmercury agarose gel electrophoresis, demonstrated that the 51,000 Mr protein specifically immunoprecipitated by the anti‐opioid receptor antiidiotype antibodies was coded by a transcript which length was in the 6 to 8 kb range. Displacement binding studies of tritiated ligands (either bremazocine or δ or μ selective peptides) with type selective opioid ligands showed that only one type of opioid binding site was synthesized in vitro. Although the pharmacological profiles of ligands binding to NG 108‐15 cells were characteristic of the δ receptor type, the de novo synthesized opioid binding site had lost its δ selectivity and showed equal affinity for both the μ and δ but not for the K ligands. Similar to our finding using the immunoprecipitation system, size fractionation of the NG108‐15 poly [A]+RNA demonstrated that the transcript coding for the “μ‐δ” binding site had a length of 6,500 to 7,500 nucleotides.
Endogenous levels of nerve growth factor (NGF) are altered in experimental diabetes mellitus: A possible role for NGF in the pathogenesis of diabetic neuropathy
Authors: Hellweg R. , Hartung H.‐D. 
Published: February 2006

AbstractSympathetic and neural‐crest derived sensory neurons consisting of unmyelinated and small myelinated fibers are known to be affected at an early stage in diabetes mellitus (DM). Since these peripheral neurons need nerve growth factor (NGF) for their development and maintenance of function in adulthood, changes in endogenous NGF levels could be of relevance for the pathogenesis of diabetic neuropathy (DNP). Using an improved two‐site enzyme immunoassay for NGF, we have investigated whether endogenous NGF levels are altered in Sprague‐Dawley rats with DM induced by a single injection of streptozotocin (STZ). STZ‐treated rats are known to develop in many respects equivalents to neuropathic complications observed in human DM. We found in some sympathetically innervated target organs decreased NGF contents by maximally 56%: transiently in the iris 2 weeks and in the ventricle 12‐24 weeks after DM induction and permanently in the submandibular gland already 3 days after DM induction. Several weeks after onset of DM, NGF content was increased by maximally 145‐300% in most peripheral targets investigated, such as in iris, cardiac atrium and ventricle, spleen, prostate gland, and vas deferens. This is suggestive for an impaired NGF removal by NGF‐sensitive neurons in diabetic rats. Moreover, NGF levels were decreased to minimally 42.6 ± 4% of control in the NGF‐transporting sciatic nerve. NGF levels began to decrease not before 3 weeks after DM induction and remained decreased with 54.0 ± 5% of control even after 6 months duration of DM. About the same time (i.e., 2 weeks after induction of DM) NGF levels began to decrease in the superior cervical ganglion (where the sympathetic perikarya are located) to minimally 53.2 ± 4% of control 12 weeks after DM induction. No altered NGF levels were observed during a 3‐month duration of DM in the terminal ileum and sensory trigeminal ganglion. Since NGF exerts its neurotrophic action in the perikarya after its retrograde transport from the NGF‐producing periphery, our results are consistent with the hypothesis that an alteration in NGF levels may play a role in the pathogenesis of DNP as far as sympathetic neurons are concerned. Thus, our results suggest that DM influences the production and/or transport of endogenous NGF and consequently, that a deprivation of this neurotrophic factor may account for some of the functional deficits known to occur in DNP, such as impaired catecholaminergic transmitter synthesis. This hypothesis possibly opens the way for new concepts in the therapy of DNP.
Defoliation and Plasmid Delivery with Layer‐by‐Layer Coated Colloids
Authors: Reibetanz Uta , Claus Claudia , Typlt Elke , Hofmann Jörg , Donath Edwin 
Published: February 2006

AbstractSummary: The uptake of polyelectrolyte multilayer coated colloids into cells, subsequent defoliation and plasmid delivery was studied by means of confocal microscopy and flow cytometry. Silica particles coated layer‐wise with protamine and dextran sulfate were given to HEK 293T cells. Optimum uptake was found with protamine as the top layer. The particle uptake likely follows an non‐receptor‐mediated endocytotic pathway. Defoliation of polyelectrolyte multilayer coated particles within cells was demonstrated by the release of incorporated plasmids as indicated by the expression of plasmid encoded proteins using the enhanced green fluorescence proteine (pEGFP‐C1) plasmid and a red fluorescence protein (pDsRed1‐N1) plasmid. This proves, together with the direct observation of fluorescent layer debris, the defoliation of coated particles and the release of layer components into the cytoplasm.Particle uptake and GFP expression.magnified imageParticle uptake and GFP expression.
Novel Functional Hyperbranched Polyether Polyols as Prospective Drug Delivery Systems
Authors: Tziveleka Leto‐Aikaterini , Kontoyianni Christina , Sideratou Zili , Tsiourvas Dimitris , Paleos Constantinos M. 
Published: February 2006

AbstractSummary: Multifunctional hyperbranched polyether polyols bearing protective poly(ethylene glycol) (PEG) chains with or without the folate targeting ligand at their end have been prepared. Solubilization in these polymers of a fluorescent probe, pyrene, and an anticancer drug, tamoxifen, was physicochemically investigated. It was found that PEG chains attached at the surface of these hyperbranched polymers, in addition to their well‐established protective role, enhance the encapsulation efficiency of the polymers. The release of pyrene and tamoxifen observed upon addition of sodium chloride is, in most of the cases, significant only at concentrations exceeding the physiological extracellular concentration. Thus, a significant amount of the probe or drug remains solubilized inside the carriers, which is an encouraging result if the polymers are to be used for drug delivery.Schematic representation of the multifunctional hyperbranched polyether polyol bearing protective poly(ethylene glycol) (PEG) chains with folate targeting ligand.magnified imageSchematic representation of the multifunctional hyperbranched polyether polyol bearing protective poly(ethylene glycol) (PEG) chains with folate targeting ligand.
Reducing superheater corrosion in wood‐fired boilers
Authors: Henderson P. , Szakálos P. , Pettersson R. , Andersson C. , Högberg J. 
Published: February 2006

AbstractOne of the major drawbacks to the combustion of 100% biomass in power station boilers is the increase in the fouling and corrosion of superheaters. Experience shows that conventional superheater steels last no more than 20 000 h or four operating years before they must be replaced, if 100% wood‐based fuel is used and the steam temperature is higher than 480°C. Rapid corrosion of superheaters leads to increased maintenance costs while widespread deposit formation gives rise to a decrease in efficiency of the turbine and an increase in unplanned outages. This paper reports on measures taken to reduce superheater corrosion.Most biomass fuels have a high content of alkali metals and chlorine, but they contain very little sulphur compared to fossil fuels. Potassium chloride, KCl, is found in the gas phase, condenses on the superheater tubes and forms complex alkali salts with iron and other elements in the steels. These salts have low melting points and are very corrosive. The corrosion can be mitigated by use of an instrument for in‐situ measurement of alkali chlorides in the flue gases, in combination with the addition of ammonium sulphate. An ammonium sulphate solution, specially developed for the reduction of corrosion was sprayed into the flue gases and effectively converted KCl into potassium sulphate, K2SO4, much less corrosive than KCl.Deposit probe tests and long‐term corrosion probe tests have been performed in‐situ in two biomass‐fired fluidised bed boilers. One boiler, 105 MWtot, 540 °C steam, is the CHP plant in Nyköping, Sweden. The other producing 98 MWtot, 480 °C steam, is a bark‐fired boiler at a pulp and paper mill in Munksund, also in Sweden. Tests have been performed with a range of steel types, ferritic and austenitic, with ammonium sulphate additive and under normal conditions (no additive). Corrosion rates have been measured, deposit chemistry analysed and flue gas chemistry and KCl content measured. The structure and composition of the oxide with and without ammonium sulphate has been investigated. The results show that ammonium sulphate reduced the KCl levels in the flue gases, removed the chlorides from the deposits and the metal/oxide interface, greatly reduced the deposition rates and halved the corrosion rates for superheater materials. The alkali chloride measuring system and the use of ammonium sulphate for the reduction of corrosion have now been patented.
Local reactions of KCl particles with iron, nickel and chromium surfaces
Authors: Cha S. C. , Spiegel M. 
Published: February 2006

AbstractCorrosion of superheaters caused by the deposition and subsequent reaction of alkali chloride containing ashes is one of the main material problems by combustion of biomass for energy conversion. The alkali chloride particles are formed during combustion and transported as aerosol or in the vapor phase within the combustion gas, subsequently sticking on the surface of the metallic tube. The initial reaction between the tube surface and the salt particle plays a major role in the initiation of the corrosion process and, therefore, are studied in detail in this work. The salt particles were locally deposited by means of thermophoresis within an aerosol generator, available at MPIE. Studies on the reaction of KCl particles with iron surfaces showed that a reaction takes place already at 300 °C. In N2‐O2 atmospheres, the attack was very local, whereas the addition of 0.05 vol.% HCl to the reaction gas led to complete coverage of the iron surface with chloride. In contrast, reactions of KCl with nickel and chromium surfaces start to be significant only at 500 °C and higher. The paper summarizes the reaction behavior of Fe, Ni and Cr after thermophoretic deposition of KCl particles and subsequent reaction at elevated temperatures.
The effect of ash deposition on corrosion behaviour of boiler steels in simulated combustion atmospheres containing carbon dioxide (CORBI PROJECT)
Authors: Środa S. , Mäkipää M. , Cha S. , Spiegel M. 
Published: February 2006

AbstractThis study is a part of the FP5 Project entitled “Mitigation of Formation of Chlorine Rich Deposits Affecting Superheater Corrosion under Co‐Combustion Conditions” (CORBI) which is aimed to improve the understanding of corrosion mechanisms in cases of biomass and waste combustion.The laboratory experiments, made at the JRC Plant Simulation Test Laboratory, are focused mainly on common ferritic and austenitic materials (X10, X20, 2.25Cr1Mo, AC66, Sanicro28, Esshette 1250, etc.), which are usually used in energy conversion systems. The experiments were carried out in multi‐sample autoclaves at an isothermal temperature of 535 °C in various simulated combustion atmospheres (22% H2O + 5% O2 + xCO2 + N 2 with different CO2 content varying from 0 to 25 vol.%) on samples with and without filter/cyclone ash deposition. The results obtained show that the corrosion rate of the studied materials increases with increasing CO2 content in the atmosphere. Such behaviour was observed for samples with and without ash deposit.The detailed analysis and thermodynamic calculations of cyclone and filter ash behaviour were performed at MPIE in Duesseldorf. The ashes were exposed to 13% CO2 + 5% O2 + xH2O + y HCl + N2 atmospheres with different H2O content varying from 5–22% and HCl content varying from 0–200 ppm at 535 °C. The results obtained show that in an HCl‐containing atmosphere the alkali chloride formed from alkali carbonate, as well as hydroxides and oxides, can additionally accelerate the oxidation process. In the HCl free atmosphere at increased H2O content, alkali carbonates and hydroxides can form, so enhanced alkali chloride induced oxidation will not occur.
The use of the 18O2‐exposure + SIMS‐based approach to investigate the spallation mechanisms of alumina scales
Authors: Jedlinski J. 
Published: February 2006

AbstractSpallation of the protective alumina scale accelerates the oxidation‐induced degradation of ‚alumina formers’︁. Despite of the vast evidence of this process its mechanism has not been elucidated, so far.This paper reports the results of the scale spallation mechanism investigation using a novel 18O2‐exposure + SIMS‐based approach. The FeCrAl‐type alumina‐forming alloys, without and with Zr additions, were subjected to high temperature exposure at 1473 K in 18O2‐rich atmosphere and, subsequently, cooled down in air. The surfaces exposed after spallation were observed using SEM, while high resolution SIMS was used to determine the elemental distributions.The obtained results indicate that: (i) in all cases the spallation occurs according to the adhesive‐mode; (ii) for reactive‐element‐free alloys the scales spalls away at temperatures high enough to enable the re‐oxidation of the exposed surface already during cooling; (iii) for the Zr‐containing alloys the spallation occurs at fairly low temperatures.Two practical implications of the obtained results should be noted: (i) oxide layers and not ‘bare substrate’ result from the scale spallation process during cooling; (ii) the formation of oxide layers during cooling may affect the behaviour of the system during subsequent heating to the reaction temperature.
High temperature corrosion of metallic materials in simulated waste incineration environments at 300–600 °C
Authors: Sánchez Pastén M. , Spiegel M. 
Published: February 2006

AbstractThe durability of the materials employed in waste incineration plants is affected by different factors that together result in severe degradation of the materials. The effects of alloying elements, as well as deposit composition and temperature range are investigated in this work. Different alloys were exposed in laboratory experiments to a specifically simulated waste incineration atmosphere N2 – 8 vol.% O2 – 2000 vppm HCl – 15 vol.% H2O – 200 vppm SO2 at 300–600 °C. The samples are covered with different salt mixtures especially chlorides and sulphates. Experiments with PbCl2‐KCl‐ZnCl2 at 450 °C, which is molten, showed catastrophic corrosion, but this was not observed in the case with KCl, which is solid. Mixtures of five different sulphates did not cause significant mass losses at 600 °C, but sulphate‐chlorided mixtures caused bigger mass losses. The presence of Al and Si in the alloys decreased mass change effects, the presence of Mo in alloys tested showed a negative effect.