bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation of Porous Polyurethane Particles and Their Use in Enzyme Immobilization
Authors: Wang X. , Ruckenstein E. 
Published: March 2005

AbstractPorous polyurethane particles were prepared as follows: (1) Two low molecular weight polymers, namely, poly[methylene(polyphenyl isocyanate)] and poly(propylene glycol) were mixed with stirring at room temperature and allowed to react. (2) The reacted mixture was dispersed with stirring in mineral oil containing small amounts of water, the catalyst dibutyltin dilaurate, and CaCO3 powder. In the presence of the catalyst, the reaction between the two polymers proceeded to completion. Small particles of polyurethane are thus formed which contain mineral oil and CaCO3 as porogens. The particles obtained, separated by filtration, were treated with a solution of HCl in order to generate additional pores, extracted with benzene to eliminate the mineral oil present in the pores, and finally subjected to drying and sieving. The particles were investigated by scanning electron microscopy (SEM), infrared (IR) spectroscopy, and specific surface area measurements. Lipase from Candida rugosa was immobilized by adsorption on the porous polyurethane particles and cross‐linked with glutaraldehyde to enhance the stability of the immobilization. The biocatalytic particles were used for the hydrolysis of triacylglycerides. The high activity of the immobilized enzyme, which per enzyme molecule can be higher than that of the free enzyme, reveals that the porous polyurethane particles constitute excellent supports for lipase.
Mathematical Characterization and Graphical Presentation of the Stiffhess‐Temperature‐Moisture Relationship of Gliadin
Authors: Peleg Micha 
Published: March 2005

AbstractPublished data for storage modulus (G′) vs temperature (T) relationships of gliadin at various moisture contents [deGraaf, E. M.; Madeka, H.; Cocero, A. M.; Kokini, J. Biotechnol Prog. 1993, 9, 210–213] were transformed into relative stiffness, R(T, M), vs temperature and moisture relationships, with the former being defined as R(T, M) = G′(T)/G′(‐50°C). These relationships could be described by the model R(T, M) = 1/{1 + exp[(T ‐ Tc(M)/a(M)]}, where both Tc(M) and a(M), as has been experimentally confirmed, are in the form of a single‐exponential decay term. This model, with the constants of the Tc(M) and a(M) terms incorporated, was also used to create three‐dimensional plots of the relative stiffness‐temperature‐moisture relationship of gliadin at and around its glass tranition, in which the combined effects of moisture and temperature are revealed visually. Although the model applicability is only demonstrated with gliadin data, there is evidence to suggest that it would also be appropriate for other biosolids.
Affinity Thermoprecipitation of Yeast Alcohol Dehydrogenase through Metal Ion‐Promoted Binding with Eudragit‐Bound Cibacron Blue 3GA
Authors: Guoqiang Dong , Benhura Mudadi A. N. , Kaul Rajni , Mattiasson Bo 
Published: March 2005

AbstractMetal ion‐promoted binding of Saccharomyces cerevisiae alcohol dehydrogenase to Cibacron Blue 3GA was used for its isolation by affinity precipitation with Eudragit‐bound dye. The yeast cells were broken and the cell debris was separated by flocculation with poly(ethylene imine). The supernatant containing the enzyme activity was mixed with Eudragit‐Cibacron Blue in the presence of zinc ions. The precipitation of the affinity complex was induced by the addition of 50 mM CaCl2 and a subsequent increase in temperature to 40 °C. The enzyme was desorbed by treating the precipitate with iminodiacetic acid solution. The procedure resulted in about 66% recovery of enzyme activity with more than 20‐fold purification. Recycling of Eudragit‐dye for enzyme purification was also shown to be possible.
Hairy Root Growth Models: Effect of Different Branching Patterns
Authors: Kim Seungdo , Hopper Elise , Hjortso Martin 
Published: March 2005

AbstractRoot growth occurs by the formation of younger lateral branches on older parent branches. This growth process can be described by the delays that occur between subsequent branching events and summarized by a set of verbal rules describing the branching kinetics in detail. A method for converting such verbal rules to a mathematical model of the branch number in a root culture under constant environmental conditions is presented here. The model of branch number is then combined with an age distribution balance to give a model of the age distribution in a root culture. Exact solution of the model is possible for deterministic branching dynamics, but results in rather cumbersome expressions for large times. Approximate solutions, valid at large times, therefore are obtained from analysis of the model. From these solutions, one readily obtains the specific growth rate of the culture, solely in terms of the branching kinetics. The extension of the modeling concepts presented here to stochastic branching rules is briefly discussed.
Dimensionless Parameters as Design Guidelines for Sterilization of Dead‐Ended Tubes
Authors: Young Jack H. , Lasher William C. 
Published: March 2005

AbstractAlthough steam‐in‐place (SIP) is the primary process for sterilization of bioreactors, sterilization guidelines do not exist for equipment design and little quantitative data are available concerning critical parameters such as length, diameter, and orientation of deadlegs. This study correlated microbiological sterilization data with the critical dimensionless parameters governing buoyancy driven convective flow within dead‐ended tubes during SIP sterilization. These parameters were shown to be the overall Grashof number, Grov, and aspect ratio, Ar. Typical values of Grov for bioprocess equipment can range from 103 to 105, while Ar may vary from near 0 to 20 during sterilization of vertical tubes at 121 °C. Reproducible sterilization resulting in a 12 log reduction in B. stearothermophilus spores required an Ar of less than 7 when Grov was 0.7 × 105, whereas an Ar of 12 could be used when Grov was 2.8 × 105.
Nonaqueous Biocatalytic Degradation of a Nerve Gas Mimic
Authors: Yang Fangxiao , Wild James R. , Russell Alan J. 
Published: March 2005

AbstractOrganophosphorus hydrolase has been shown to be an effective catalyst for the continuous decontamination of a nerve agent in a continuous gas phase reactor. Very small quantities of the enzyme are sufficient to enable detoxification of low concentrations of the nerve agent for extended periods of time. In the case where the nerve agent is at high concentrations (a liquid), the enzyme has also been shown to be active in biphasic mixtures of a solvent with water. The activity and specificity of the enzyme in both environments (continuous gas phase and biphasic mixture) obey classical models of enzyme kinetics. The activity of the enzyme in such extreme environments enables optimization of systems capable of continuous gas or liquid phase biocatalytic degradation of highly toxic chemicals.
Studies of High Solidity Ratio Hydrofoil Impellers for Aerated Bioreactors. 2. Air—Water Studies
Authors: Mcfarlane Caroline M. , Zhao Xue ‐Ming , Nienow Alvin W. 
Published: March 2005

AbstractThis second part of a four‐part series of papers reports on the hydrodynamic and power characteristics of two commercial, high solidity ratio, hydrofoil impellers, the Prochem Maxflo T and the Lightnin A315, in an air—water system. Studies were conducted primarily in a mixing vessel of diameter 0.56 m. The influence of operating conditions (impeller speed and gas flow rate) and sparger position and geometry on bulk flow patterns, gas filled cavity formation, and power consumption have been investigated in detail. In the turbulent Reynolds number region, the unaerated impeller power numbers are constant with average values of 1.30 for the Prochem and 0. 76–0.84 for the A315, depending on impeller position relative to the base of the vessel. Gassed power consumption is closely linked to cavity type and flow pattern. In particular, the development of large cavities causes a significant reduction in power drawn, impeller pumping capacity, and gas dispersion capability. As with downward pumping mixed flow impellers, two characteristic gas loading regimes, direct and indirect loading, can be identified. Under certain conditions, severe hydrodynamic instabilities over the transition between the two regimes give rise to very large torque and power fluctuations. Changes in reactor geometry can have a significant effect on impeller performance. Thus, sparger type and position have a strong influence on relative power drawn, gas handling capability, power required to disperse gas and stability of operation. Of the configurations studied, the use of a large ring sparger (DS/D = 0.8D) at a large sparger—impeller separation is suggested, since relative power drawn, gas handling capability, and energy efficiency in dispersing gas are all enhanced.
Model for the Formation of Silicon Carbide from the Pyrolysis of Dichlorodimethylsilane in Hydrogen: I, Silicon Formation from Chlorosilanes
Authors: Cagliostro Domenick E. , Riccitiello Salvatore R. 
Published: March 2005

Silicon tetrachloride is a major product of the pyrolysis of dichlorodimethylsilane in hydrogen. A model is developed for the deposition of silicon from the reduction of silicon tetrachloride with hydrogen in a tubular reactor at temperatures from 700° to 1100°C and 1.013 × 105 Pa (1 atm) pressure. Concentrations of silicon tetrachloride varied from 1 to 9 vol%. Gas chromatography was used to determine the volatile products of reaction, and gravimetric analysis was used to determine the total silicon deposition on the tube. The model, based on the experimental data, assumes the following reversible chemical reactions:

image
The rate constants derived from a nonlinear regression analysis are reported.
Transient Plastic Phase Processing of Titanium–Boron–Carbon Composites
Authors: Barsoum Michel W. , Houng Boen 
Published: March 2005

Ceramic/ceramic composites in the Ti‐B‐C system were fabricated by a novel process referred to as transient plastic phase processing (TPPP). The basic concept is based on the following reaction:

“soft” transient plastic matrix
+ reactant phase → hard matrix
+ reinforcement phase

where the transient plastic phase is a phase with a wide range of stoichiometry and a yield point that is a strong function of that stoichiometry. The reactant phase is one that will react with the transient phase in such a way so as to shift the composition of the latter toward its harder and more refractory composition. The composite is formed in two stages: In the first, pressure is applied to shape and fully densify the reactants while the transient phase is soft, i.e., before reaction. Once the reactants are densified, the reaction is allowed to proceed, forming a new phase and rendering the matrix more refractory. If the volume change upon reaction is small, then the density of the final compact will remain near theoretical. Using this approach ceramic/ceramic composites in the Ti─B─C system were hotpressed to full density and complex shapes at temperatures as low as 1600°C.
Interleukin 4, interleukin 6 and interleukin 10 polymorphisms in children with acute and chronic immune thrombocytopenic purpura
Authors: Wu Kang‐Hsi , Peng Ching‐Tien , Li Tsai‐Chung , Wan Lei , Tsai Chang‐Hai , Lan Shou‐Jen , Chang Ming‐Cheng , Tsai Fuu‐Jen 
Published: March 2005

SummaryImmune thrombocytopenic purpura (ITP) is an immune‐mediated disorder. We investigated the polymorphisms of interleukin (IL)‐4 intron 3, IL‐6 (−572 G/C), and IL‐10 (−627 C/A) in 50 children with acute ITP, 30 children with chronic TIP, and 100 healthy individuals. There were significant differences in the RP1/RP2 genotype proportion (P = 0·04) and the RP2 allelic frequency (P = 0·03) of IL‐4 intron 3 and the A/C genotype proportion (P = 0·01) of IL‐10 (−627) between children with chronic ITP and controls. This finding suggests that the IL‐4 intron 3 and IL‐10 (−627) polymorphisms contribute to the susceptibility of developing childhood chronic ITP.
An evaluation of rapid D‐dimer assays for the exclusion of deep vein thrombosis
Authors: Gardiner Chris , Pennaneac'h Coralie , Walford Claire , Machin Samuel J , Mackie Ian J 
Published: March 2005

SummaryWe evaluated the performance of eight d‐assays for the exclusion of deep vein thrombosis (DVT); Biopool AutoDimer, Biopool MiniQuant, bioMèrieux MDA d‐Dimer, VIDAS, Dade Behring d‐Dimer Plus, Trinity Biotech AMAX, NycoCard d‐dimer and IL Test d‐Dimer. The assays were evaluated both as stand‐alone tests, and in combination with pretest probability (PTP). d‐dimer assays and PTP assessment were performed on 410 patients presenting to the emergency department with suspected acute DVT. DVT was diagnosed in 76 of 410 patients (18·5%) by compression ultrasound or other imaging techniques, as required. Receiver operator characteristics analysis established optimum cut‐off values and these were compared with manufacturer's cut‐off values where provided. As stand‐alone tests, the assays varied immensely regarding cut‐off value, negative predictive value (NPV 93–100%) and specificity (0–67%). At least one patient with confirmed DVT had a low d‐dimer level by each method: to achieve 100% sensitivity it would be necessary to reduce cut‐off values to levels below clinical usefulness. When low d‐dimer was used in combination with PTP, six of eight methods achieved ≥98% NPV, with a diagnosis of DVT excluded in 16–44% of patients without the requirement for diagnostic imaging. The highly variable diagnostic performance of these d‐dimer assays means that some assays are unsuitable for certain diagnostic strategies. However, our data suggest that the combination of sensitive d‐dimer assays with an assessment of PTP may be used to exclude a diagnosis of DVT.
Takayasu's arteritis: what should the dentist know?
Authors: DUQUE C. , SILVA R. C. , SANTOS‐PINTO L. 
Published: March 2005

Summary.Takayasu's arteritis is a chronic inflammatory disease that affects large blood vessels, especially the aorta and/or its major branches. The condition presents with segmental lesions adjacent to normal, apparently unaffected, areas. The lesions include stenosis, occlusion, dilatations or aneurysm formations along the path of the affected artery. Because of the severity of the disease and the possibility of cardiovascular complications, patients with Takayasu's arteritis require medical treatment based on immunosuppressive and antihypertensive drugs, as well as regular follow up and surgical intervention in many instances. The aim of this paper was to describe the characteristics of Takayasu's arteritis, to report dental treatment carried out on an affected patient, and to discuss the main implications and care required during routine treatment for children in the dental office.
Seasonal Differences in the Secretion of Luteinising Hormone and Prolactin in Response to N‐Methyl‐dl‐Aspartate in Starlings (Sturnus vulgaris)
Authors: Dawson A. 
Published: March 2005

AbstractIn birds, unlike mammals, seasonal changes in reproductive function are associated with marked changes in the amount of gonadotrophin‐releasing hormone (GnRH) stored in the hypothalamus. Prolonged exposure to long photoperiods leads to photorefractoriness after the breeding season. Photorefractory birds have low hypothalamic concentrations of chicken GnRH‐I (cGnRH‐I). Exposure to short photoperiods results in renewed cGnRH‐I synthesis and increased hypothalamic stores. Birds are then photosensitive and subsequent exposure to an increase in photoperiod results in increased cGnRH‐I secretion and gonadal maturation. However, it is unclear whether the reverse is true at the time of gonadal regression during long photoperiods (i.e. that a decrease in GnRH‐I synthesis precedes regression). Hypothalamic stores of cGnRH‐I, and possibly therefore of releasable GnRH‐I, decrease after regression. Single injections of the glutamate agonist N‐methyl‐dl‐aspartate (NMA) were used as a probe to assess releasable stores of cGnRH‐I in male starlings at four physiologically different reproductive stages. Treatment induced the greatest increase in luteinising hormone (LH) in photosensitive birds in January, and a slight increase in sexually mature birds in April. There was a slight but significant increase in June, immediately after testicular regression, but no increase in fully photorefractory birds in September. These data confirm that photorefractoriness is associated with a lack of releasable cGnRH‐I, but that decreased synthesis of cGnRH‐I is not the proximate cause of regression. There was an increase in prolactin in response to NMA at all times. The magnitude of the response was proportional to pre‐treatment concentrations, with the greatest response in June. It is suggested that high circulating prolactin may fine‐tune the timing of gonadal regression in advance of the inhibition of cGnRH‐I synthesis.
Perforating disorder caused by salt‐water application and its experimental induction
Authors: Lee S. J. , Jang J. W. , Lee W. C. , Kim D. W. , Jun J. B. , Bae H. I. , Kim D. J. 
Published: March 2005

AbstractBackground   Perforating disorders are uncommon diseases characterized by transepidermal elimination histopathologically and include reactive perforating collagenosis, elastosis perforans serpiginosa, Kyrle's disease and perforating folliculitis. In addition, perforating disorders can develop in patients with diabetes mellitus, renal failure and even by accidental exposure of calcium salts.Methods   We report two cases of perforating disorder caused by chemical burn with commercially available salt‐water* application for self‐treatment of chronic dermatitis or pruritus.Results   The commercially used salt water for making bean curd was analyzed and it consisted of calcium and other salts without harmful heavy metals. We induced a similar phenomenon by experimental application of commercial salt water on guinea pigs.Conclusion   Bean curd is used as a food commonly in the Far‐East, allowing a greater chance of exposure to salt water accidentally or occupationally. Bean curd is becoming more popular even in Western countries. To confirm causation, we induced a similar phenomenon in guinea pigs by experimental application of commercial salt water.*Salt water# (‘Kansoo’ in Korean) is used in the solidifying process of bean curd.
Solitary asymptomatic nodule of the great toe
Authors: Guarneri Claudio , Guarneri Fabrizio , Risitano Giovanni , Lentini Maria , Vaccaro Mario 
Published: March 2005

AbstractSubungual exostosis is a benign osteocartilaginous tumor of the ungual apparatus, particularly of the toes. It affects both sexes equally, more frequently in the second and third decades of life. We describe a 6‐year‐old girl who came to our attention because of the enlargement of a pinkish nodule in the distal part of the nail bed of the first toe, progressively elevating the nail plate. History, X‐ray imaging and histopathologic examination led us to confirm our clinical suspicion, excluding any other possible cause of the subungual mass. The peculiar features of this clinical entity, and the possibility of effective treatment by practical surgical techniques, are discussed.
Patient characteristics and costs associated with dyslipidaemia and related conditions in HIV‐infected patients: a retrospective cohort study
Authors: Richter A , Pladevall M , Manjunath R , Lafata JE , Xi H , Simpkins J , Brar I , Markowitz N , Iloeje UH , Irish W 
Published: March 2005

BackgroundMetabolic abnormalities are common in HIV‐infected individuals and, although multifactorial in origin, have been strongly associated with antiretroviral therapy.MethodsUsing automated claims and clinical databases, combined with medical record data, we evaluated the burden of dyslipidaemia (DYS) and associated metabolic abnormalities among a cohort of 900 HIV‐infected patients aged 18 years and older who received their care from a large multispecialty medical group between 1 January 1996 and 30 June 2002. A Cox proportional hazards model for DYS was developed. Resource use was compiled and subsequently costed with stratification to account for variable length of follow‐up.ResultsMean follow‐up time was 3.3 years. DYS was present in 54% of the cohort and 3.4% experienced a cardiovascular (CV) event. Both unadjusted and adjusted results found patients with dyslipidaemia and cardiovascular events significantly more likely to have received protease inhibitor (PI) treatment for longer periods of time. In the Cox proportional hazards model the following factors were significantly associated with an increased risk for DYS: older age, white race, PI use and male sex. Diagnoses of hypertension, hepatitis C virus infection, depression or opportunistic infections were all negatively associated with a DYS diagnosis. When controlled for length of follow up, patients with DYS (and no CV‐related events) incurred greater median and mean total average costs than patients without DYS or CV‐related events. For patients with more than 2 years of follow up, these total cost differences were statistically significant (P<0.05).ConclusionsThese findings indicate that DYS is common among patients with HIV infection and is associated with increased use of medical resources.
Enhanced glucagon‐like peptide‐1 (GLP‐1) response to oral glucose in glucose‐intolerant HIV‐infected patients on antiretroviral therapy
Authors: Andersen O , Haugaard SB , Holst JJ , Deacon CF , Iversen J , Andersen UB , Nielsen JO , Madsbad S 
Published: March 2005

ObjectivesWe investigated whether the incretin hormones glucagon‐like peptide‐1 (GLP‐1) and glucose‐dependent insulinotropic polypeptide (GIP), which are major regulators of glucose tolerance through the stimulation of insulin secretion, contribute to impaired glucose tolerance (IGT) among HIV‐infected patients on highly active antiretroviral therapy (HAART).MethodsEighteen HIV‐infected male patients (six lipodystrophic and 12 nonlipodystrophic) with normal glucose tolerance (NGT) were compared with 10 HIV‐infected male patients (eight lipodystrophic and two nonlipodystrophic) with IGT. Plasma concentrations of GLP‐1 and GIP were determined frequently during a 3‐h, 75‐g glucose tolerance test. Insulin secretion rates (ISRs) were calculated by deconvolution of C‐peptide concentrations.ResultsThe incremental area under the curve (incrAUC) for GLP‐1 was increased by 250% in IGT patients compared with NGT patients (1455±422 vs. 409±254 pmol/L/180 min, respectively; P<0.05), whereas the incrAUC for GIP did not differ between the study groups (7689±1097 vs. 8041±998 pmol/L/180 min, respectively; not significant). In pooled study groups, the GIP incrAUC correlated positively with the ISR incrAUC without adjustment (r=0.38, P<0.05) and following adjustment for glucose incrAUC (r=0.49, P<0.01).ConclusionsOur data suggest: (1) that glucose‐intolerant, HIV‐infected male patients may display enhanced GLP‐1 responses to oral glucose compared with normal glucose‐tolerant HIV‐infected male patients, which may represent a compensatory mechanism rather than explain the IGT; (2) that the GIP response may be associated with ISR independently of plasma glucose in nondiabetic HIV‐infected males on HAART.