bluuebunny/crossref_metadata_2025 huggingface dataset:
A Second‐Generation Genome Screen for Linkage to Type 1 Diabetes in a Bedouin Arab Family
Authors: BABU SUNANDA R. , CONANT GAVIN C. , ELLER ELISE , ROBERTS CHRISTINE M. , GOWAN KATHERINE , EISENBARTH GEORGE S. , FAIN PAMELA R. , VARDI PNINA
Published: February 2005

Abstract: IDDM17 on chromosome 10 was identified in an initial genome screen of 13 members (10 affected) of a large Bedouin Arab family that had 19 relatives affected with type 1 diabetes. Two more children have now been diagnosed with the disease. A second genome screen with 45 members (17 affected members, spouses, and offspring; 382 markers) was performed. A parallel version of Genehunter was used for parametric and nonparametric linkage analyses. The nonparametric linkage analysis (NPL) confirmed the IDDM17 locus (NPL = 3.79; P= 0.001) with a prominent LOD (logarithm of the odds = 2.38) peak. These results demonstrate the strong potential of genetically homogenous, extended families for mapping genes that contribute to a complex disease.
Association of the Polymorphism for Toll‐like Receptor 2 with Type 1 Diabetes Susceptibility
Authors: PARK YONGSOO , PARK SUKYUNG , YOO EUNKYUNG , KIM DUKHEE , SHIN HYONGDOO
Published: February 2005

Abstract: Type 1 diabetes mellitus (T1DM) is a T cell‐mediated autoimmune disease in which pancreatic β cells are selectively destroyed. Although autoimmune diseases are driven by inappropriate adaptive immunity, innate immunity may play a role in the development of T1DM. We investigated the association of the genes for toll‐like receptor 2 (TLR2), one of the key surface receptors on innate effectors, with T1DM in Korean patients. Genetic association analyses revealed that the genotype composed of the rare allele (CC) of TLR2 1350 showed weak and protective association with T1DM (OR = 1.7, 95% CI: 1.1‐2.7; P < .05) irrespective of the duration of disease, age, and autoantibody status. One of the TLR2 SNP haplotypes, TLR2‐Ht4, was strongly associated with T1DM in that those subjects having more than one copy of Ht4 showed strong protection from developing T1DM (OR = 90.5; 95% CI: 13.8‐235.7; P < 10−5). The TLR2 polymorphisms are associated with T1DM, and distribution differences between T1DM versus controls were not influenced by the HLA genes. There is a close relationship between innate and adaptive immunity.
Immunohistochemical Demonstration of Nitrotyrosine, a Biomarker of Oxidative Stress, in Islet Cells of the NOD Mouse
Authors: REDDY SHIVA , BRADLEY JOSHUA
Published: February 2005

Abstract: Reactive oxygen species and nitric oxide generated within the beta cell or by intraislet immune cells may be major mediators of beta cell death during insulin‐dependent diabetes mellitus. Here, the intraislet expression of nitrotyrosine, a biomarker of oxidative damage, and its cellular sources were examined in the islets of NOD mice at various stages of spontaneous and cyclophosphamide‐accelerated diabetes. At day 30, nitrotyrosine‐positive cells were undetectable; they were rare at day 40, being expressed in only a few beta cells and in macrophages located in the periphery of some islets. At day 90 and at onset of diabetes, an increasing number of macrophages and beta cells were nitrotyrosine positive. In the cyclophosphamide group at day 4, the number of beta cells and macrophages with positive immunolabeling declined slightly from day 0 (day of cyclophosphamide injection = day 90). This pattern of immunolabeling increased gradually by day 7 but increased markedly by days 11 and 14 after cyclophosphamide administration. In the spontaneous and cyclophosphamide groups, macrophages were the predominant source of nitrotyrosine and were present within the intraislet and periislet regions. Nitrotyrosine labeling was observed in a significant number of beta cells but less than in immunolabeled macrophages. We conclude that protein nitration in beta cells and macrophages is an important feature of the diabetogenic process in the NOD mouse. Whether this deleterious process also occurs during the very early stages of the disease and preceding insulitis is unclear.
Short-Term Zoledronic Acid Treatment Increases Bone Mineral Density and Marrow Clonogenic Fibroblast Progenitors after Allogeneic Stem Cell Transplantation
Authors: Tauchmanovà Libuse , Ricci Patrizia , Serio Bianca , Lombardi Gaetano , Colao Annamaria , Rotoli Bruno , Selleri Carmine
Published: February 2005

Although osteoporosis is a relatively common complication after allogeneic stem cell transplantation, the role of bisphosphonates in its management has not yet been completely established. Thirty-two patients who underwent allogeneic stem cell transplantation were prospectively evaluated for bone mineral density (BMD) at the lumbar spine (LS) and femoral neck (FN) after a median period of 12.2 months. Then, 15 of the patients with osteoporosis or rapidly progressing osteopenia (bone loss > 5%/yr) received three monthly doses of 4 mg zoledronic acid iv. Fifteen patients were followed up without treatment, and all 30 patients were reevaluated after 12 months for BMD and bone turnover markers. By using enriched mesenchymal stem cells in the colony-forming units fibroblast (CFU-F) assay, we evaluated the osteogenic stromal lineage. This procedure was performed in both groups of patients at study entry and after 12 months. The average BMD loss was 3.42% at LS and 3.8% at FN during a 1-yr longitudinal evaluation in 32 patients. Subsequently, BMD increased at both LS and FN (9.8 and 6.4%, respectively) in the zoledronic acid-treated cohort. Hydroxyproline excretion decreased, and serum bone-specific alkaline phosphatase increased significantly, whereas serum osteocalcin increase did not reach the limit of significance. A significant increase in CFU-F growth in vitro was induced by in vivo zoledronic acid administration. In the untreated group, no significant change was observed in bone turnover markers, LS BMD (–2.1%), FN BMD (–2.3%), and CFU-F colony number.

In conclusion, short-term zoledronic acid treatment consistently improved both LS and FN BMD in transplanted patients who were at high risk for fast and/or persistent bone loss, partly by increasing the osteogenic progenitors in the stromal cell compartment.
Amplification of the Steroidogenic Factor 1 Gene in Childhood Adrenocortical Tumors
Authors: Figueiredo Bonald C. , Cavalli Luciane R. , Pianovski Mara Albonei D. , Lalli Enzo , Sandrini Romolo , Ribeiro Raul C. , Zambetti Gerard , DeLacerda Luiz , Rodrigues Giovanna Assis , Haddad Bassem R.
Published: February 2005

Southern Brazil has one of the highest incidences of childhood adrenocortical tumors (ACTs), occurring 10–15 times more frequently than worldwide estimates. The reasons for this increase remain elusive. In an attempt to further characterize the genetic changes in childhood ACTs, we recently detected a consistent gain of 9q (or a portion of it) in eight of nine cases of pediatric ACTs and amplification of 9q34 in the majority of these cases using comparative genomic hybridization. Other studies involving both childhood and adult ACTs have corroborated these findings. To follow up on these results, we examined whether the steroidogenic factor 1 (SF-1) gene, which is located in this chromosomal region and plays an important role in the development and function of the adrenal cortex is amplified in these ACT cases. We detected increased copy number of the SF-1 gene in all eight cases with 9q gain, suggesting an association between an increased copy number of the SF-1 gene and adrenocortical tumorigenesis.
The Insulin Gene Variable Number Tandem Repeat and Risk of Type 2 Diabetes in a Population-Based Sample of Families and Unrelated Men and Women
Authors: Meigs James B. , Dupuis Josée , Herbert Alan G. , Liu Chunyu , Wilson Peter W. F. , Cupples L. Adrienne
Published: February 2005

Abnormalities in insulin regulation are central to the pathogenesis of type 2 diabetes. We assessed variation in the insulin gene variable number tandem repeat (INS VNTR) minisatellite (using the −23Hph1 A/T single nucleotide polymorphism) as a risk factor for 92 cases of incident type 2 diabetes in 883 unrelated Framingham Heart Study (FHS) subjects and in a separate sample of 698 members of 282 FHS nuclear families with 62 diabetes cases. In the unrelated sample, the −23Hph1 TT genotype frequency was 8.0% and was associated with a diabetes hazard ratio of 1.89 [95% confidence interval (CI), 1.01–3.52; P = 0.045] compared with the AA genotype using diabetes age of onset as the time failure variable in a proportional hazards model adjusted for age, offspring sex, body mass index, parental diabetes, and sex by parental diabetes interactions. In sex-stratified analyses, TT increased risk for diabetes in women (hazard ratio, 4.25; 95% CI, 1.76–10.3), but not men (hazard ratio, 1.01; 95% CI, 0.39–2.60). Using a family-based association test to assess transmission disequilibrium in the sample of related subjects, the age- and sex-adjusted z-score for diabetes associated with the T allele was 2.07 (P = 0.04), and a family-based association test using age of onset in a proportional hazards model was also statistically significant (P = 0.03), indicating that increased risk of diabetes was not attributable to population admixture. These data support the hypothesis that the INS VNTR is a genetic risk factor for type 2 diabetes, with the TT genotype accounting for about 6.6% of cases in the FHS population.
Postprandial Plasma Ghrelin Is Suppressed Proportional to Meal Calorie Content in Normal-Weight But Not Obese Subjects
Authors: le Roux C. W. , Patterson M. , Vincent R. P. , Hunt C. , Ghatei M. A. , Bloom S. R.
Published: February 2005

Circulating levels of the gastric hormone ghrelin rise before and decrease after a meal. In normal-weight subjects, postprandial suppression of ghrelin is proportional to calories consumed. Obese individuals have lower fasting ghrelin levels; however, it is unclear whether the obese show normal postprandial suppression. This study aimed to compare postprandial ghrelin responses in normal-weight and obese subjects, using mixed macronutrient meals with varied fat and calorie content. Postprandial ghrelin response was measured in normal-weight insulin-sensitive subjects and obese insulin-resistant subjects, after six test meals with different fat and calorie content (250–3000 kcal). Increasing the calorie content of meals in normal-weight subjects progressively lowered nadir levels of ghrelin. The obese had lower fasting ghrelin levels, and the reduction after the consumption of all test meals was less than the normal-weight subjects. The lowest postprandial levels in the obese were no different to the nadir in normal-weight volunteers after 1000-, 2000-, and 3000-kcal meals. Thus, circulating ghrelin levels decreased in normal-weight subjects after mixed meals. Obese subjects demonstrated a much reduced ghrelin postprandial suppression. This reduced suppression may influence satiety, thus reinforcing obesity.
Essential Role of Fibroblast Growth Factor Signaling in Preadipoctye Differentiation
Authors: Patel Nayan G. , Kumar Sudhesh , Eggo Margaret C.
Published: February 2005

We have examined the expression and role of autocrine fibroblast growth factors (FGFs) in human preadipocytes through their differentiation in vitro. A high-molecular weight form of FGF-2 was initially strongly expressed, but 6–9 d after induction of differentiation, its expression decreased markedly. This coincided with the first appearance of visible lipid droplets within the cells. FGF-2 (18 kDa) was not found. FGF receptor (FGFR) 1 was detected as a single band of 125 kDa that also decreased with differentiation. Its decrease preceded that of FGF-2. Despite the decrease in cell-associated FGF-2 with differentiation, secreted FGF-2 was 2.5-fold higher in the differentiated preadipocytes. To determine whether FGF-2 had an autocrine role, FGFR signaling was inhibited using recombinant adenovirus expressing dominant negative FGFR1 (RAdDN-FGFR1) and a specific inhibitor of FGFR1 signaling, PD166866. Preadipocytes transduced with RAdDN-FGFR1 expressed a truncated, 79-kDa FGFR1. Differentiation, assessed by lipid droplet formation, was completely prevented by RAdDN-FGFR1 and by PD166866. The protein content in the cell layer and glucose uptake were significantly reduced by both agents. The insulin-sensitizing drug, rosiglitazone, did not prevent the actions of RAdDN-FGFR1 or PD166866. Controlling adipose tissue growth by limiting FGF actions may provide a means to combat obesity.
Human Plasma Ghrelin Levels Increase during a One-Year Exercise Program
Authors: Foster-Schubert Karen E. , McTiernan Anne , Frayo R. Scott , Schwartz Robert S. , Rajan Kumar B. , Yasui Yutaka , Tworoger Shelley S. , Cummings David E.
Published: February 2005

Weight loss resulting from decreased caloric intake raises levels of the orexigenic hormone, ghrelin. Because ingested nutrients suppress ghrelin, increased ghrelin levels in hypophagic weight loss may result from decreased inhibitory input by ingested food, rather than from lost weight. We assessed whether ghrelin levels increase in response to exercise-induced weight loss without decreased caloric intake. We randomized 173 sedentary, overweight, postmenopausal women to an aerobic exercise intervention or stretching control group. At baseline, 3 months, and 12 months, we measured body weight and composition, food intake, cardiopulmonary fitness (maximal oxygen consumption), leptin, insulin, and ghrelin. Complete data were available for 168 women (97%) at 12 months. Exercisers lost 1.4 ± 0.4 kg (P < 0.05 compared with baseline; P = 0.01 compared with stretchers) and manifested a significant, progressive increase in ghrelin levels, whereas neither measure changed among stretchers. Ghrelin increased 18% in exercisers who lost more than 3 kg (P < 0.001). There was no change in caloric intake in either group and no effect on ghrelin of exercise per se independent of its impact on body weight. In summary, ghrelin levels increase with weight loss achieved without reduced food intake, consistent with a role for ghrelin in the adaptive response constraining weight loss and, thus, in long-term body weight regulation.
A new design concept for wrist arthroplasty
Authors: Shepherd D E T , Johnstone A J
Published: February 2005

The wrist joint is frequently affected by arthritis, which leads to pain, loss of function and ultimately deformity. Various designs of wrist arthroplasty have been introduced to attempt to relieve pain and provide a functional range of motion. The first generation of wrist implant was a one-piece silicone elastomer. Later generations have designs that have two parts that articulate against each other. However, wrist implants have not achieved the same clinical success to date, compared with hip and knee implants, and there is a high revision rate associated with them. This paper describes a new design concept for wrist arthroplasty, based around the idea of combining the principles of an articulating implant with that of a flexible elastomer implant. The design consists of assembling a radial, carpal/metacarpal, plate and flexible parts together. The radial and carpal/metacarpal parts are to be made from ultra high molecular weight polyethylene. The bearing surfaces of the radial and carpal/metacarpal parts articulate against the flat surfaces of the plate, made from cobalt chrome molybdenum alloy. The radius on the bearing surface of the radial part enables flexion/extension, while the radius on the carpal/metacarpal surface enables radial/ulnar deviation. The articulation of the carpal/metacarpal part against the plate also allows for rotation as well as flexion/extension. The flexible part, made from Elast-Eon, which is a silicone polyurethane elastomer, is inserted through the hole of the plate and into the holes of the radial and carpal/metacarpal parts.
Stereoselective α-Hydrazination of α,β-Unsaturated Carboxylates Catalyzed by Manganese(III) Complex with Dialkylazodicarboxylate and Phenylsilane
Authors: Sato Mitsuo , Gunji Yasuhiko , Ikeno Taketo , Yamada Tohru
Published: February 2005

In the presence of a catalytic amount of bis(dipivaloylmethanato)manganese(III) complex, the α,β-unsaturated carboxylates with camphorsultam as a chiral auxiliary reacted with phenylsilane and dialkyl azodicarboxylates to afford the corresponding α-hydrazinated carboxylates with high stereoselectivities.
Ab Initio Study of the Electronic Spectrum of 7-Hydroxyquinoline
Authors: Franz Jan , Peyerimhoff Sigrid D , Hanrath Michael , Kwon Oh-Hoon , Jang Du-Jeon
Published: February 2005

The electronic spectrum of 7-hydroxyquinoline has been studied by using ab initio Multi-State Multi-Reference Møller-Plesset Second-Order Perturbation Theory (MSMRMP2). The energy range up to 6.5 eV is taken into consideration. The lowest π–π* transition is calculated to have an energy of 3.65 eV in good agreement with experimental data. Several other π–π* transitions are predicted to have excitation energies of 4.93, 5.20, 5.47, and 6.08 eV. Excitations out of the highest occupied σ orbital into the lowest unoccupied π* orbitals are computed to occur at 5.28 and 6.44 eV. The π–σ* transition is predicted at 5.87 eV. The σ* orbital involved is identified as the Rydberg 3s orbital having antibonding character along the OH bond.
Co2(CO)8 as Novel and Water-tolerant Reagent for the Conversion of Azides to Amines in Aqueous Media
Authors: Yadav J S , Reddy B V S , Satheesh G , Rao K Raghavender
Published: February 2005

Azides are readily converted into their corresponding amines using a catalytic amount of Co2(CO)8 under mild conditions. The method is highly chemoselective and compatible with a variety of functionalities such as halides, esters, acids, ethers, nitro, cyano and olefinic double bonds present in the molecule.
Preparation of Anodic Porous Alumina Mask with Ideally Arranged Holes on InP Single Crystals
Authors: Yasui Kenji , Sakamoto Yasuhisa , Nishio Kazuyuki , Masuda Hideki
Published: February 2005

Anodic porous alumina mask with ideally arranged holes was formed on InP single crystals. This process has advantageous in the achievement of nanofabrication with uniformity and reproducibility due to the mask being formed with sufficient adhesion on the InP. The masks formed by this process, was confirmed to applicable for the dry-process mask.
Total Synthesis of (±)-Arohynapene B
Authors: Sugimura Hideyuki , Uchida Yuki
Published: February 2005

The total synthesis of (±)-arohynapene B, an anticoccidial agent isolated from the fermentation broth of a fungal strain, has been achieved. The tetrahydronaphthalene ring was constructed by the Diels–Alder reaction between dimethyl acetylenedicarboxylate and the 1-(β-acetoxyvinyl)cyclohexene derivative, which was prepared from 3,5-dimethylcyclohexanone via the Ag+-catalyzed rearrangement of the propargylic acetate derivative. The introduction of the dienylcarboxylic acid side chain was accomplished by the Horner–Wadsworth–Emmons olefination repeatedly utilizing ethyl diethylphosphonoacetate. Finally, careful removal of the protecting groups led to (±)-arohynapene B.
The immunodetection of lipoprotein-bound amyloid-β is attenuated because of the presence of lipids
Authors: James AP , Mamo JCL
Published: February 2005

Background: Amyloid-β (Aβ) is found in circulation and cerebrospinal fluid (CSF), predominantly associated with lipoproteins. However, in a lipid environment it is possible that a masking of Aβ epitopes and/or an altered conformation of Aβ leads to an underestimation of Aβ concentrations.

Methods: We generated lipoprotein-like lipid emulsions containing a known amount of Aβ and compared immunoreactivity with an equimolar amount of Aβ solubilized in an aqueous medium.

Results: We found that Aβ exists primarily as a dimer and a monomer within an aqueous and lipid environment, respectively. We also showed that lipids bind tightly to Aβ, blocking detection of the monomeric form and substantially attenuating detection of the dimeric form of the protein.

Conclusion: It is possible that studies that have quantified the concentration of Aβ in plasma and CSF may have significantly underestimated the pool of lipoprotein-bound Aβ.
First trimester maternal serum screening for Down's syndrome: an evaluation of the DPC Immulite 2000 free β-hCG and pregnancy-associated plasma protein-A assays
Authors: Spencer Kevin
Published: February 2005

Background: Recent NICE Guidelines have emphasized the need to have in place by 2007 the capability of offering screening to all women in the first trimester using a combination of maternal age with the ultrasound marker nuchal translucency thickness (NT) and the maternal serum biochemical markers free β-hCG and pregnancy-associated plasma protein-A (PAPP-A). Laboratories will therefore need to consider how to introduce the biochemical component of screening. With the recent launch of these assays on the DPC Immulite 2000 platform, it is appropriate and timely to investigate their clinical and analytical performance on a high throughput immunoassay analyser.

Methods: Within-run and between-day precision was assessed in the normal way. Bias was assessed by comparing samples from normal pregnancies ( n = 813) and pregnancies with Down's syndrome ( n = 60) run on both the DPC system and our routine Kryptor system. Gestational day-specific medians for each marker were calculated from the unaffected population. Mathematical modelling was used to predict the clinical performance of the two markers.

Results: The within-run coefficient of variation (CV) was around 3.5% and between-day CV was around 6-8% for both assays. Comparison with EQA samples showed a 2% positive bias against the ALTM for free β-hCG and a 21% positive bias for PAPP-A, which reduced to 11% when compared with the Kryptor method mean. When compared with the Kryptor, the DPC free β-hCG showed a significant concentration-related negative bias above concentrations of 50 IU/L in both unaffected and affected pregnancy samples. After conversion to MoM in the Down's syndrome group, the DPC free β-hCG assay showed a MoM-related bias at higher MoM values. For PAPP-A a positive MoM-related bias was also evident. In cases with Down's syndrome, the median free β-hCG MoM was 1.703 for DPC and 1.698 by the Kryptor, which was not significantly different. For PAPP-A, the median MoM was 0.62 for DPC and 0.47 by the Kryptor, which was significantly ( P = 0.025) different. This difference, if real, is likely to result in a lower detection of cases with Down's syndrome. Statistical modelling techniques suggest that this would be 58% compared with the expected 67% when combined with maternal age and free β-hCG. When combined with NT, however, this would be reduced to 85% compared with the 90% expected.

Conclusions: While laboratories may find some organizational benefit from running first trimester Down's syndrome screening on such routine high-throughput immunoassay analysers, better clinical performance is likely to be achieved with alternative platforms to the DPC Immulite 2000.
Carbon Dioxide Emission Trends and Environmental Problems in Turkey
Authors: Demirbas M. Fatih , Bozbas Kahraman , Balat Mustafa
Published: February 2005

Turkey's carbon emissions have risen in line with the country's energy consumption. However, energy-related CO2 emissions per capita and per gross domestic product are both increasing. Energy-related CO2 emissions from coal and coal products decreased slightly between 1990 and 2000 while that of oil and gas increased. As CO2 emissions increased from 160 Mt in 1995 to nearly 240 Mt in 2000, they are expected to rise to 400 Mt by 2010 and up to 700 Mt by 2020. In Turkey total CO2 emissions from fossil fuels, about 50.07 Mt in 2001. However, fuel share of carbon emissions in 2001: oil 44.2%, coal 38.8%, and NG 16.9%.
Cellulosic Fabric Wastes Grafted with DMAEMA for the Removal of Direct Dyes
Authors: Sokker H.H. , Halim E.S. Abdel , Aly A.S. , Hashem A.
Published: February 2005

Dimethylaminoethyl methacrylate (DMAEMA) was grafted onto a cellulosic fabric waste via γ-irradiation (60Co). Factors affecting the grafting such as the radiation dose and monomer concentration were investigated. The grafted fabric waste was studied by infrared (FT-IR) spectroscopy and thermogravimetric analysis (TGA), as well as its surface morphology. The ability of the grafted fabric waste for removing Direct Violet 31 from its aqueous solution was studied by batch experiments. The adsorption data obeyed the Langmuir and Freundlich isotherms. It was found that 1 g of grafted fabric waste adsorbed 40 mg of Direct Violet 31 from its aqueous solution. The grafted fabric waste could be used as an adsorbent for water pollutants such as dyes, thereby solving one of the most important environmental problems of the textile industry.
Thin-Layer Film with an Incorporated Pyrazoloquinoline Derivative as a Fluorescent Sensor for Nucleotides
Authors: Cywiński Piotr , Wandelt Barbara , Danel Andrzej
Published: February 2005

A thin-layer film comprising poly(methyl methacrylate) with an incorporated pyrazolo[3,4- b]quinoline derivative was prepared. The dye was anchored onto the polymer film to form a molecular assembly at the surface. Fluorescence quenching of this thin-layer sensory system was observed when the film was incubated in the presence of the nucleotide guanosine-3′,5′-cyclic monophosphate. Steady-state and time-resolved fluorescence techniques were used to study the fluorescence quenching of this sensory system in the presence of nucleotides. The results suggest that quenching of a pyrazoloquinoline fluorosensor by nucleotide anions cannot be described simply by a collision mechanism employing the Stern-Volmer equation, but there is a possibility of the formation of a more stable association. This type of sensing polymer layer plays a role in biotechnology because it can be immobilized at the end of a fibre optic and used for measuring nucleotide concentrations within a biological system.
Structure and Reactivity of a V2O5/Al2O3 Catalyst Modified with Cerium in the Oxidative Dehydrogenation of Cyclohexane
Authors: AbdelDayem Hany M.
Published: February 2005

The oxidative dehydrogenation (ODH) of cyclohexane with air was studied on a 10 w/w% V2O5/Al2O3 catalyst modified by different weight percentage (wt%) cerium loadings. The catalysts employed were characterized by N2 adsorption, O2 chemisorption, TEM, XRD and FT-IR spectroscopy. Benzene and cyclohexene were the main components of the products, with the benzene and cyclohexene selectivities depending on the wt% cerium loading, the order of cerium and vanadium impregnation, and the reaction temperature. The best cyclohexane conversion and good benzene selectivity were obtained at 500°C using a vanadium catalyst modified by 10 wt% cerium. The same catalyst exhibited a maximum selectivity for cyclohexene at 300°C.

Different types of vanadyl species present in the system were identified by IR measurements. Thus, vanadium-oxygen clusters were detected in the V2O5/Al2O3 material, although such clusters were not found in the cerium-vanadium catalysts. Polymeric CeVO4 species were detected in cerium-modified V2O5/Al2O3 catalysts by XRD. The concentration of these species depended on the wt% cerium loading and the order of cerium and vanadium impregnation on alumina. The selectivity of cerium-modified V2O5/Al2O3 catalysts towards cyclohexene was attributed mainly to the presence of such polymeric CeVO4 species. Oxygen chemisorption and electronic microscopic studies attributed the marked improvement in cyclohexane conversion of the cerium-vanadium samples to the presence of relatively high-dispersed vanadium species.
Large Scale Hydrogen Production from Wind Energy in Patagonia, Argentina
Authors: Mönnich Kai , Neumann Thomas , Strack Martin , Braess Holger , Scheuerer Klaus
Published: February 2005

This paper summarises a feasibility study for large-scale production of liquid hydrogen from wind power in East Patagonia. An investigation and valuation of the wind potential and infrastructure indicate that in the Provinces of Chubut (357,000 inhabitants) and of Santa Cruz (160,000 inhabitants), three Regions are especially suitable for building up such a system. The Region of Comodoro Rivadavia has been chosen for an exemplary system-layout because of the accurate meteorological database and the best infrastructure possibilities combined with a large wind potential. Two system layouts have been developed, which differ mainly in the method of energy transmission. A cost evaluation showed no significant differences in specific energy costs between the two layouts. The analysis shows that the production of liquid hydrogen now is not presently competitive with fossil fuels at market price (taxes included), but an outlook to the year 2025 shows that the production of liquid hydrogen may be economically feasible in the future.
Redox Flow Batteries: Modelled for Power Quality Improvements in Autonomous Wind-Diesel Power Systems
Authors: Lone Shameem Ahmad , Mufti Mairaj ud-Din
Published: February 2005

A redox flow battery (RFB), as with superconducting magnetic energy storage, has a high speed response, and its active and reactive powers can be modulated in the four quadrants of the power chart. This type of rechargeable battery is not aged by frequent charging and discharging, and the battery efficiency increases when the charging/discharging period becomes shorter. Moreover, in practical applications a RFB has several advantages, such as operation at ambient temperature, short duration overload capability, small power loss during standby, a long service life, flexibility in layout and ease of power output capacity enhancement. These characteristics make the RFB most suitable for power quality improvement in autonomous power systems. In this paper we propose the application of an RFB for power quality improvement of an isolated wind diesel power system. Suitable control strategies, based on fuzzy logic are used to modulate the exchange of real and reactive powers between the RFB system and the ac bus of the wind diesel power system. The effectiveness of the proposed scheme in dealing with various perturbations is then studied and the results are presented.
The Role of Medium Voltage Electrical System Design in Risk Management for Offshore Wind Farms
Authors: Pechey Jim , Taylor Philip , Dixon Richard , Lawson Mark , Dinning Andrew
Published: February 2005

In the short-term future, UK offshore wind-farms are to be connected to the grid by Medium Voltage (MV) electrical systems. This connection is required not only for export of power but also to provide essential power supplies to critical equipment within the wind-farm. There are perceived risks to these connections, which can result in significant loss of revenue and deterioration of equipment. This paper presents the findings of a DTI funded programme of research into available MV equipment and configurations, to establish the risks of failure to these MV systems and to provide a practical guide for selecting the optimum system configuration for a particular application. Offshore access relies greatly on the prevailing weather conditions. Therefore the critical factor determining the degree of MV system sophistication is often the degree of exposure of the wind-farm to inclement weather conditions and the distance from the wind-farm to the shore.
Structural probing of a pathogenic tRNA dimer
Authors: ROY MARC D. , WITTENHAGEN LISA M. , KELLEY SHANA O.
Published: February 2005

The A3243G mutation within the human mitochondrial (hs mt) tRNALeu(UUR) gene is associated with maternally inherited deafness and diabetes (MIDD) and other mitochondrial encephalopathies. One of the most pronounced structural effects of this mutation is the disruption of the native structure through stabilization of a high-affinity dimeric complex. We conducted a series of studies that address the structural properties of this tRNA dimer, and we assessed its formation under physiological conditions. Enzymatic probing was used to directly define the dimeric interface for the complex, and a discrete region of the D-stem and loop of hs mt tRNALeu(UUR) was identified. The dependence of dimerization on magnesium ions and temperature was also tested. The formation of the tRNA dimer is influenced by temperature, with dimerization becoming more efficient at physiological temperature. Complexation of the mutant tRNA is also affected by the amount of magnesium present, and occurs at concentrations present intracellularly. Terbium probing experiments revealed a specific metal ion-binding site localized at the site of the A3243G mutation that is unique to the dimer structure. This metal ion-binding site presents a striking parallel to dimeric complexes of viral RNAs, which use the same hexanucleotide sequence for complexation and feature a similarly positioned metal ion-binding site within the dimeric structure. Taken together, these results indicate that the unique dimeric complex formed by the hs mt tRNALeu(UUR) A3243G mutant exhibits interesting similarities to biological RNA dimers, and may play a role in the loss of function caused by this mutation in vivo.
Elimination of Zinc from Roof Runoff through Geotextile and Clinoptilolite Filters
Authors: Athanasiadis Konstantinos , Helmreich Brigitte , Wilderer Peter A.
Published: February 2005

Direct infiltration of roof runoff into the ground may pose a potential risk of soil and groundwater contamination. The performance of two different barrier materials for the retention of zinc from roof runoff of an eleven year old zinc roof was examined in a field study. As barrier materials geotextile and clinoptilolite were applied. Automatic samplers were used to take samples both at the inlet and at the outlet of the retention facility. Samples of twenty rain events were examined. Zinc was detected in the roof runoff in concentrations of up to 25 mg/L, and lead which originates from the tin‐solder was present in concentrations of up to 84 μg/L. Under most circumstances, a first flush could be observed for the analysed substances. No retention of heavy metals was observed, where only geotextile was used as a barrier material. The clinoptilolite filter was able to adsorb up to 97 % of zinc from the roof runoff.
The Determination of Relationship between Zooplankton and Abiotic Factors Using Canonical Correspondence Analysis (CCA) in the Ova Stream (Ankara/Turkey)
Authors: Akbulut Nuray (Emir)
Published: February 2005

In this study totally 25 rotifer species, 3 cladocerus species, and 2 copepoda species were identified in Ova Stream. Among zooplankton rotifer species were dominant. Population densities of planktonic organisms were calculated as individual per cubic meter and the relationship of the planktonic organisms with physicochemical parameters was determined applying canonical correspondence analysis (CCA). Also diversity index has been calculated according to the sampling stations. According to the results, the diversity index changes between stations and sampling time. The CCA results show that the rotifer species Keratella, Notholca showed negative correlation with the increasing chemical parameters and temperature but Brachionus, Mytilina, Colurella, and Testudinella have positive correlation with increasing temperature.
Optimisation of the Operation of an Electrochemical Process To Treat TBT‐contaminated Sediments on a Pilot Scale
Authors: Arevalo Eduardo , Keller Arne , Stichnothe Heinz , Calmano Wolfgang
Published: February 2005

Since at least three decades tributyltin had been commonly used in paint formulations to protect ship hulls and submersed surfaces from fouling. This has resulted in negative and Technology, effects to the marine environment due to its high toxicity towards non‐target organisms and to its accumulation in sediments, especially near point sources of pollution. Even if a ban of TBT for its application in anti‐fouling paints is enforced the problem of TBT‐contaminated sediments will remain for the coming years due to the low degradation rates of organotin in sediments. In this work an electrochemical process at a pilot scale to destroy TBT in sediments was investigated. Previous experiences at a laboratory and technical scale have demonstrated the potential of this process to electrolytically degrade organotin species in sediments.

This article deals with the optimisation of the pilot plant performance in terms of organotin degradation and operation costs monitoring additionally the effect of the electrochemical treatment on other pollutants such as heavy metals, PCBs, and PAHs.

The aim was to investigate by means of a parametric study the range of operating conditions required to destroy TBT down to concentrations lower than 100 μg/kg; to determine the influence of those parameters on the performance of the process; and to evaluate the operation costs associated to the process. It was determined that it was possible to destroy TBT down to 100 μg/kg at current densities in the range of 4.4 to 6.6 mA/cm2 and chloride concentrations of least of 0.2 mol/L with operation costs of 13 to 18 EUR/m3.
Retardation of Fin Regeneration in Freshwater Fish Oreochromis mossambicusby Zinc
Authors: Verma Yogendra
Published: February 2005

Regeneration of partially amputated caudal fin was studied in freshwater fish Oreochromis mossambicus exposed to sublethal concentrations of zinc (5.0 mg L—1 and 10.0 mg L—1) under ambient laboratory conditions over a period of 20 days. Caudal fin regeneration was measured on 5th, 10th, 15th and 20th day of exposure and after amputation. Significant ( p < 0.05) retardation in fin regeneration was observed on day 5th and 10th in fish exposed to the nominal concentration of 5.0 mg L—1 Zn, while retardation was found highly significant ( p < 0.01) at all the observations in 10.0 mg L—1. The maximum inhibition in caudal fin regeneration (20.8 % and 24.3 %) was found during the initial observation at both of the concentrations (5.0 mg L—1 and 10.0 mg L—1) of zinc exposure. Later on the regeneration rate was almost as good as in the control group. Thus in this study fin regeneration was significantly inhibited at all time points following Zn exposure as a detrimental effect of Zn to fish. This study demonstrates that fish caudal fin regeneration is a simple assay, sensitive and easy to perform, and can serve as a model to determine the toxicity of pollutants in aquatic environment.
Optimal feeding for tower‐type reactors
Authors: Fu Chun‐Chong , Lu Shih‐Yuan , Wu Wen‐Teng
Published: February 2005

In tower‐type reactors, poor mixing is a major concern in fermentation processes. As an attempt to improve the mixing efficiency, an algorithm based on the analytic solution of the modified network‐of‐zones model and application of the singular value decomposition technique is proposed to determine the optimal feeding locations and corresponding amounts of feed in airlift reactors, bubble column reactors, and airlift reactors with wire‐mesh draft tube. The optimal feeding locations and corresponding amounts of feed predicted by the algorithm are in good agreement with the experimental results. The proposed algorithm is proved to be an effective method for optimizing the feeding operation to improve the mixing efficiency for the three tower‐type reactors. © 2005 American Institute of Chemical Engineers AIChE J, 51: 713–724, 2005
Three‐dimensional simulation of bubble column flows with bubble coalescence and breakup
Authors: Chen P. , Duduković M. P. , Sanyal J.
Published: February 2005

Three‐dimensional (3‐D) Euler/Euler simulations of two‐phase (gas/liquid) transient flow were performed using a multiphase flow algorithm based on the finite‐volume method. These numerical simulations cover laboratory‐scale bubble columns of different diameters, operated over a range of superficial gas velocities in the churn‐turbulent regime (8 to 30 cm/s) and at different operating pressures (up to 1 MPa). The bubble population balance equation (BPBE) is implemented in the two‐fluid model (TFM) and algebraic slip mixture model (ASMM). Simulated time‐averaged axial liquid velocity, turbulence stress, and gas holdup are compared with experimental data of Chen et al., Ong, and Shaikh et al. Moreover, to ensure the experimentally observed lack of dependency of holdup radial profiles on column height in the fully developed region, coalescence rates in the computations had to be enhanced consistently compared to model‐predicted values. Quantitative agreement is then obtained between the experimental data and simulations for the time‐averaged gas holdup and axial liquid velocity profiles. However, the simulations significantly underestimate the turbulent stress because the velocity field cannot be fully resolved. Simulated bubble size distributions indicate that the volume fraction of small bubbles is uniform in a cross section, whereas that of the large bubbles peaks in the center of the column. The simulation correctly captures the high‐pressure effect, which at fixed gas superficial velocity pushes the bubble column flow toward bubbly flow. The simulation also predicts that, although the small bubble volume fraction may not change with superficial gas velocity in the churn‐turbulent flow regime, the bubble size distribution still remains single modal but is wider and contains larger bubble sizes when superficial gas velocity is increased. © 2005 American Institute of Chemical Engineers AIChE J, 51: 696–712, 2005
Kinetics and mechanism of the K2CrO4NaAsO2 redox‐initiated aqueous polymerization of acrylonitrile
Authors: Maity Arjun , Biswas Mukul
Published: February 2005

The kinetics and mechanism of acrylonitrile polymerization initiated by a redox pair [potassium chromate (K2CrO4) and sodium arsenite (NaAsO2)] were studied. The overall rate of polymerization was proportional to √[K2CrO4] × [NaAsO2], and the energy of activation was approximately 10.5 kJ/mol. Polyacrylonitrile was recovered as a coagulum in the medium. The formation of polyacrylonitrile was confirmed with Fourier transform infrared and 1H‐NMR analyses. Scanning electron microscopy analysis of the polymer revealed the formation of aggregates of polymer particles (3–67 nm). Thermogravimetric studies indicated 50% weight loss at 400°C, and dynamic thermal analysis scan studies revealed an exothermic peak at 507°C due to massive oxidative thermal degradation of the polyacrylonitrile backbone. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 276–280, 2005
Electrically modulated transport of diclofenac salts through hydrogels of sodium alginate, carbopol, and their blend polymers
Authors: Agnihotri Sunil A. , Kulkarni Raghavendra V. , Mallikarjuna Nadagouda N. , Kulkarni Padmakar V. , Aminabhavi Tejraj M.
Published: February 2005

The electrically modulated transdermal migration of diclofenac sodium (DS), diclofenac potassium (DP), and diclofenac diethylammonium (DD) drugs from the hydrogels of sodium alginate (NaAlg), carbopol (CP), and blends of NaAlg with CP prepared in 2:1, 2:1.5, and 2:2 ratios was investigated. The release of DS, DP, and DD was investigated through excised rat skin to study the effects of viscosity, pH, and the ionic strength of the receptor medium under the influence of an electrical current in a switch‐on and switch‐off mode. A pulsatile pattern of transport was observed that depended on the presence or absence of an electrical current. Drug transport was dependent on the electrical current, the ionic nature of drugs, and the ionic strength of the diffusion medium. Drug transport followed the sequence DS > DP > DD. A decrease in viscosity and an increase in the pH of the hydrogel were observed when an electrical current was applied. CP was more responsive to an electrical stimulus, but the rate of transport was higher for NaAlg. Increasing the amount of CP in the blends increased the electrical responsiveness. The blend hydrogel with a high CP content showed the highest enhancement in drug transport, whereas the NaAlg hydrogel showed the least. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 301–311, 2005
Preparation, structure, and properties of a novel rectorite/styrene–butadiene copolymer nanocomposite
Authors: Wang Yiqing , Zhang Huifeng , Wu Youping , Yang Jun , Zhang Liqun
Published: February 2005

Rectorite/styrene–butadiene copolymer (SBR) nanocomposite was prepared by cocoagulating SBR latex and rectorite/water suspension. Transmission electron microscopy showed that the layers of rectorite were well dispersed in the SBR matrix and the aspect ratio (width/thickness) of it was higher than that of montmorillonite (MMT). X‐ray diffraction indicated that the nanocomposite produced by this method was of neither intercalated type nor exfoliated type. The gas barrier properties and mechanical properties of the novel nanocomposites were excellent. The nanocomposites are expected to be candidates for tire tube or inner materials. Rectorite appears to be a promising filler for the nanocomposite. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 324–328, 2005
Kinetics and modeling of diethylene glycol bisallyl carbonate bulk polymerization
Authors: Hace Iztok , Golob Janvit , Krajnc Matjaž
Published: February 2005

The free‐radical polymerization kinetics of diethylene glycol bisallyl carbonate in bulk were investigated with Fourier transform infrared and Fourier transform Raman techniques in a wide temperature range of 50–140°C with four different peroxide initiators. In addition, the ratios of the degradative kinetic rate constant to the propagation rate constant under different reaction conditions were obtained from molecular weight measurements under various reaction conditions. The ratio of the chemically controlled termination and propagation rate constants of the polymerization system were obtained with the initial rates of polymerization and the number‐average molecular weight data, which were between 8.22 × 10−5 and 1.47 × 10−3 L mol−1 s−1. The initiator efficiencies were evaluated with special experiments at low initiator concentrations with the theory of dead‐end polymerization. The computed conversions from the developed kinetic model were in good agreement with the conversion and molecular weight measured data. The values of the diffusion‐controlled propagation and termination rate constants, with clear and physical meaning, were the only two parameters obtained from the developed kinetic model fitting the measured conversion points. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 345–357, 2005
Synthesis and characterization of side‐chain liquid‐crystalline polyurethane elastomers
Authors: Wang Tzong‐Liu , Tsai Jung‐Shian , Tseng Ching‐Guey
Published: February 2005

Side‐chain liquid‐crystalline (SCLC) polyurethane elastomers with methoxybiphenyl mesogens pendant on the chain extenders were synthesized by the conventional prepolymer technique and condensation reaction. Two SCLC polyurethanes with mesogens having spacers of six and eight methylene units were prepared. The structures of the mesogenic units and SCLC polyurethanes were confirmed by Fourier transform infrared and 1H‐NMR. The polymer properties were also studied with solubility tests, water‐uptake measurements, and inherent‐viscosity measurements. The tensile properties indicated that both SCLC polyurethanes were thermoplastic elastomers. Their phase‐transition temperatures were studied with differential scanning calorimetry. Wide‐angle X‐ray diffraction studies revealed the existence of liquid‐crystalline phases for both SCLC polyurethanes. Polarizing optical microscopy investigations further confirmed the thermotropic liquid‐crystalline behaviors and smectic mesophases of both samples. Thermogravimetric analysis results showed a more rapid degradation in the initial stage and a slower degradation process in the latter stage for both SCLC polymers in comparison with those of the linear starting polyurethane. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 336–344, 2005