bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simplified, automated synthesis of 3′[18F]fluoro-3′-deoxy-thymidine ([18F]FLT) and simple method for metabolite analysis in plasma
Authors: Reischl G. , Blocher Achim , Wei Rongqing , Ehrlichmann Walter , Kuntzsch Matthias , Solbach Christoph , Dohmen Bernhard M. , Machulla Hans-Jürgen 
Published: August 2006

Summary3′[18F]Fluoro-3′-deoxy-thymidine ([18F]FLT) (III) has been discussed to be a promising tracer for assessing tumor proliferation. In order to perform clinical studies for evaluating [18F]FLT a simplified labeling procedure was developed using 2,3′-anhydrothymidine with benzoyl as a protecting group in the 5′-position (I). In DMSO the labeling yield was 46% at 160 °C in 10 min. Hydrolysis was efficiently performed with 0.25% NaOH at room temperature within 10 min. The labeling procedure was transferred to a remote controlled synthesis module allowing the production of [18F]FLT in high activities. The overall radiochemical yield was 18.1 ± 5.4% (n= 55) with absolute yields of 9.2 ± 2.6 GBq of [18F]FLT at EOS ready for injection (60 min after EOB; irradiation parameters: 35 μA, 60 min) and specific activities of 100–220 GBq/μmol. A convenient cartridge method for metabolite analysis was developed and validatedversusHPLC showing that after 90 min 69.0 ± 7.0% of the radioactivity in plasma (less than 20% of initial radioactivity) was unchanged [18F]FLT (26 patients with various tumors).
Substoichiometric extraction of iron by 2-methyloxine inton-butanol
Authors: Mandal M. , Pal D. , Basu S. 
Published: August 2006

SummaryDetermination of iron(III) by substoichiometric extraction with 2-methyloxine inton-butanol is being reported. The method has been applied for the determination of the metal in several analyzed samples like Mn-bronze, Al-bronze and dolomite.
Determination of stability constants of lanthanide nitrate complex formation using a solvent extraction technique
Authors: Andersson Sofie , Eberhardt Klaus , Ekberg Christian , Liljenzin Jan-Olov , Nilsson Mikael , Skarnemark Gunnar 
Published: August 2006

Summary
For lanthanides and actinides, nitrate complex formation is an important factor with respect to the reprocessing of nuclear fuels and in studies that treat partitioning and transmutation/conditioning. Different techniques, including microcalorimetry, various kinds of spectroscopy, ion-exchange and solvent extraction, can be used to determine stability constants of nitrate complex formation. However, it is uncommon that all lanthanides are studied at the same time, using the same experimental conditions and technique. The strengths of the complexes are different for lanthanides and actinides, a feature that may assist in the separation of the two groups. This paper deals with nitrate complex formation of lanthanides using a solvent extraction technique. Trace amounts of radioactive isotopes of lanthanides were produced at the TRIGA Mainz research reactor and at the Institutt for Energiteknikk in Kjeller, Norway (JEEP II reactor).
The extraction of lanthanide ions into an organic phase consisting of 2,6-bis-(benzoxazolyl)-4-dodecyloxylpyridine, 2-bromodecanoic acid and tert-butyl benzene as a function of nitrate ion concentration in the aqueous phase was studied in order to estimate the stability constants of nitrate complex formation. When the nitrate ion concentration is increased in the aqueous phase, the nitrate complex formation starts to compete with the extraction of metal ions. Thus the stability constants of nitrate complex formation can be estimated by measuring the decrease in extraction and successive fitting of an appropriate model.
Extraction curves for La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Dy, Ho and Er were obtained and stability constants for their nitrate complex formation were estimated. Tb, Tm, Yb and Lu were also investigated, but no stability constants could be determined. The distribution ratios for the metal ions at low nitrate ion concentration were obtained at the same time, showing the effect of lanthanide contraction resulting in decreasing extraction along the series. A clear tetrad effect in the lanthanide group was also found.
A simplified reaction model predicting the effect of some parameters on the degradation of phenol in the electron beam process
Authors: Pellizzari Fabien , Follut Florian , Karpel Vel Leitner Nathalie 
Published: August 2006

Summary
Electron beam irradiation is a known advanced oxidation process that is studied in the literature to examine the possibilities of pollutant removal from waters. In the present work, a common pollutant, phenol, was chosen as model molecule to investigate the capability of a simple reaction system to predict the influence of certain parameters on the efficiency of the electron beam process. This model is based on the main reactions occurring during the irradiation of aqueous solutions of phenol. It was found to simulate suitably the effect of the dissolved oxygen and of the initial concentration on the abatement of the molecule during the irradiation.
Various irradiation experiments were also performed by modifying the mode of the dose deposition. The results showed that, for a given applied dose, the multiplication of the passages under the electron beam significantly improves the abatement of phenol (20%). The oxygenation of the solution and the mathematical expression of the evolution of the pollutant concentration with the radiation dose partly explain this improvement.
Plasma dipeptidyl peptidase-IV activity in patients with type-2 diabetes mellitus correlates positively with HbAlc levels, but is not acutely affected by food intake
Authors: Ryskjær Jakob , Deacon Carolyn F , Carr Richard D , Krarup Thure , Madsbad Sten , Holst Jens , Vilsbøll Tina 
Published: August 2006

Objective: Glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide are incretin hormones, secreted in response to meal ingestion. The incretin hormones stimulate insulin secretion and are essential for the maintenance of normal plasma glucose concentrations. Both incretin hormones are metabolized quickly by the enzyme dipeptidyl peptidase-IV (DPP-IV). It is well known that type-2 diabetic patients have an impaired incretin effect. Therefore, the aim of the present study was to investigate plasma DPP-IV activity in the fasting and the postprandial state in type-2 diabetic patients and control subjects.
Design: The study included two protocols. Protocol one involved 40 fasting type-2 diabetic patients (28 men); age 61 ± 1.4 (mean ± s.e.m.) years; body mass index (BMI) 31 ± 0.6 kg/m2; HbAlc 7.2 ± 0.2%; and 20 matched control subjects (14 men) were studied. Protocol two involved eight type-2 diabetic patients (six men); age 63 ± 1.2 years; BMI 33 ± 0.5 kg/m2; HbAlc 7.5 ± 0.4%; eight matched control subjects were included.
Methods: In protocol one, fasting values of DPP-IV activity were evaluated and in protocol two, postprandial DPP-IV activity during a standard meal test (566 kcal) was estimated.
Results: Mean fasting plasma DPP-IV activity (expressed as degradation of GLP-1) was significantly higher in this patient group compared with the control subjects (67.5 ± 1.9 vs 56.8 ± 2.2 fmol GLP-1/h (mean ± s.e.m.); P=0.001). In the type-2 diabetic patients, DPP-IV activity was positively correlated to FPG and HbAlc and negatively to the duration of diabetes and age of the patients. No postprandial changes were seen in plasma DPP-IV activity in any of the groups.
Conclusions: Plasma DPP-IVactivity increases in the fasting state and is positively correlated to FPG and HbAlc levels, but plasma DPP-IV activity is not altered following meal ingestion and acute changes in plasma glucose.
Normative data for adiponectin, resistin, interleukin 6, and leptin/receptor ratio in a healthy Spanish pediatric population: relationship with sex steroids
Authors: Martos-Moreno Gabriel Á , Barrios Vicente , Argente Jesús 
Published: August 2006

Objectives: To investigate the circulating levels of adiponectin, resistin, interleukin 6 (IL-6), and leptin/receptor ratio in healthy Spanish children throughout the different stages of pubertal development. To analyze the relationship between adipokines and sex steroid level changes during puberty.
Study design: Serum adiponectin, resistin, IL-6 levels, and leptin/receptor ratio were studied in 160 healthy Spanish children grouped according to their pubertal stage (Tanner I, 23 girls and 22 boys; Tanner II, 19 girls and 16 boys; Tanners III and IV, 21 girls and 20 boys; and Tanner V, 20 girls and 19 boys). In addition, circulating levels of sex hormone-binding globulin (SHBG) were determined in every subject, and testosterone and estradiol levels in boys and girls respectively.
Results: Adiponectin levels decreased in boys from mid puberty (P < 0.05) to become significantly lower than in girls (P < 0.001), whereas IL-6 decreased in both sexes (P < 0.05). Resistin levels and leptin/receptor ratio showed no differences between sexes or according to pubertal stage, except in adult females, who had the highest levels of both parameters (P < 0.001). Serum IL-6 levels correlated significantly (P < 0.05) with testosterone and estradiol levels (r=−0.37 and −0.42 respectively), whereas estradiol, but not testosterone, correlated with leptin/receptor ratio (r=0.59; P < 0.001). Furthermore, a positive relationship was found between SHBG and adiponectin and IL-6 (P < 0.001 and P < 0.05 respectively). In addition, a direct correlation between leptin/receptor and body mass index was found in both sexes (P < 0.001).
Conclusion: Variations in adipokine profiles throughout pubertal development appear to be related with progression of gonadal function.
Adiponutrin gene is regulated by insulin and glucose in human adipose tissue
Authors: Moldes Marthe , Beauregard Geneviève , Faraj May , Peretti Noël , Ducluzeau Pierre-Henri , Laville Martine , Rabasa-Lhoret Rémi , Vidal Hubert , Clément Karine 
Published: August 2006

Objective: Adiponutrin is a new transmembrane protein specifically expressed in adipose tissue. In obese subjects, short- or long-term calorie restriction diets were associated with a reduction in adiponutrin gene expression. Adiponut.rin mRNA level was previously shown to be negatively correlated with fasting glucose plasma levels and associated with insulin sensitivity of non-diabetic obese and non-obese subjects. The purpose of the present work was to get more insight into the regulation of adiponutrin gene expression by insulin and/or glucose using clamp studies and to examine its potential dysregulation in subjects with a deterioration of glucose homeostasis.
Methods: Adiponutrin gene expression was quantified by reverse transcriptase-quantitative PCR in s.c. adipose tissue of healthy lean subjects after an euglycemic hyperinsulinemic clamp (EGHI), a hyperglycemic euinsulinemic clamp, and a hyperglycemic hyperinsulinemic (HGHI) clamp. Adiponutrin gene expression was also analyzed in patients with different levels of insulin resistance.
Results: During EGHI, insulin infusion induced adiponutrin gene expression 8.4-fold (P = 0.008). Its expression was also induced by glucose infusion, although to a lesser extend (2.2-fold, P = 0.03). Infusion of both insulin and glucose (HGHI) had an additive effect on the adiponutrin expression (tenfold, P = 0.008). In a pathological context, adiponutrin gene was highly expressed in the adipose tissue of type-1 diabetic patients with chronic hyperglycemia compared with healthy subjects. Conversely, adiponutrin gene expression was significantly reduced in type-2 diabetics (P = 0.01), but remained moderately regulated in these patients after the EGHI clamp (2.5-fold increased).
Conclusion: These results suggest a strong relationship between adiponutrin expression, insulin sensitivity, and glucose metabolism in human adipose tissue.
Weights in the cohomology of toric varieties
Authors: Weber Andrzej 
Published: August 2006

Abstract
We describe the weight filtration in the cohomology of toric varieties. We present a role of the Frobenius automorphism in an elementary way. We prove that equivariant intersection homology of an arbitrary toric variety is pure. We obtain results concerning Koszul duality: nonequivariant intersection cohomology is equal to the cohomology of the Koszul complexIH
T*(X)⊗H*(T). We also describe the weight filtration inIH
*(X).
Crystallinity Control of a Nanostructured LiNi0.5Mn1.5O4 Spinel via Polymer‐Assisted Synthesis: A Method for Improving Its Rate Capability and Performance in 5 V Lithium Batteries
Authors: Arrebola J. C. , Caballero A. , Cruz M. , Hernán L. , Morales J. , Castellón E. R. 
Published: August 2006

AbstractLi–Ni–Mn spinels of nominal composition LiNi0.5Mn1.5O4, which are functional materials for electrodes in high‐voltage lithium batteries, are prepared by thermal decomposition of mixed nanocrystalline oxalates obtained by grinding hydrated salts and oxalic acid in the presence of polyethyleneglycol 400. Their structure, microstructure, and texture are established from combined X‐ray photoelectron spectroscopy (XPS), X‐ray diffraction, transmission electron microscopy (TEM), IR spectroscopy, and N2 absorption measurements. The polymer tailors the shape of particles, which adopt a nanorodlike morphology at low temperatures (400 °C). In fact, the nanorods consist of highly distorted oriented nanocrystals connected by a polymer‐based film as inferred from IR and XPS spectra. The electrochemical properties of spinels in this peculiar form are quite poor, mainly as a result of the high microstrain content of their nanocrystals. Raising the temperature up to 800 °C partially destroys the nanorods, which become highly crystalline nanoparticles approximately 80 nm in size. At this temperature, the polymer facilitates crystal growth; this leads to highly crystalline polyhedral nanoparticles as revealed from TEM images and microstrain data. Following functionalization as a cathode in lithium cells, this material exhibits a very good rate capability, coulombic efficiency, and capacity retention even upon cycling at voltages as high as 5 V. Moreover, it withstands fast‐charge–slow‐discharge processes, which is an important cycle‐life‐related property for commercial batteries.
Straightforward Synthesis of a Fluorous Tetraarylporphyrin: an Efficient and Recyclable Sensitizer for Photooxygenation Reactions
Authors: Pozzi Gianluca , Mercs Lászlo , Holczknecht Orsolya , Martimbianco Fabio , Fabris Fabrizio 
Published: August 2006

AbstractA fluorous tetraarylporphyrin has been prepared in a single reaction step starting from commercially available 5,10,15,20‐tetrakis(4‐hydroxyphenyl)porphyrin [TPP(OH)4]. The new compound was successfully employed as a sensitizer in photooxygenation reactions carried out under homogeneous conditions, showing activity comparable to the standard 5,10,15,20‐tetraphenylporphyrin (TPP) sensitizer. Photooxygenation reactions were also investigated under fluorous biphasic conditions, yielding somewhat different product distributions. Because of its fluorous nature, the new porphyrin could be easily removed from the homogeneous mixture by liquid‐liquid or solid phase extraction. In the case of fluorous biphasic reactions, the fluorous sensitizer could be recovered by simple phase separation and then reused, maintaining its efficiency at least upon five subsequent runs.
Multiphase Systems for the Recycling of Alkoxycarbonylation Catalysts
Authors: de Pater Jeroen J. M. , Deelman Berth‐Jan , Elsevier Cornelis J. , van Koten Gerard 
Published: August 2006

AbstractThis review evaluates the various multiphasic systems that have been developed for catalyst recycling in the context of alkoxycarbonylation of alkenes and alkynes. Immobilization of the catalyst on an insoluble support, such as silica, alumina, clay or a polymer, as well as immobilization in the inorganic phase of several liquid/liquid biphasic systems (aqueous/organic, ionic liquid/organic, fluorous/organic or supercritical CO2/organic) has been described. In several cases detailed information on the efficiency of catalyst separation and recycling is available. Most of the work was focused on the alkoxycarbonylation reactions of alkenes, for which several efficient methods for catalyst recycling were demonstrated. The recycling of catalyst through specific precipitation from supercritical CO2 or selective dissolution in a fluorous phase, has received only scant attention but offers many opportunities for further improvement.
Water‐Soluble Group 8 and 9 Transition Metal Complexes Containing a Trihydrazinophosphaadamantane Ligand: Catalytic Applications in Isomerization of Allylic Alcohols and Cycloisomerization of (Z)‐Enynols in Aqueous Medium
Authors: Díaz‐Álvarez Alba E. , Crochet Pascale , Zablocka Maria , Duhayon Carine , Cadierno Victorio , Gimeno José , Majoral Jean Pierre 
Published: August 2006

AbstractAn optimized synthesis of the 2,4,10‐trimethyl‐1,2,4,5,7,10‐hexaaza‐3‐phosphatricyclo[3.3.1.13,7]decane ligand (THPA) is described. It readily reacts with the dimers [{RuCl(μ‐Cl)(η6‐arene)}2] and [{MCl(μ‐Cl)(cod)}2] to yield the corresponding mononuclear complexes [RuCl2(THPA)(η6‐arene)] [arene=C6H6 (4a), p‐cymene (4b), 1,3,5‐C6H3Me3 (4c), C6Me6 (4d)] and [MCl(THPA)(cod)] [M=Rh (7a), Ir (7b)], respectively. Treatment of 4a and b with MeOTf affords the cationic derivatives [RuCl2(THPA‐Me)(η6‐arene)][OTf] {arene=C6H6 (5a), p‐cymene (5b); THPA‐Me=1,2,4,10‐tetramethyl‐2,4,5,7,10‐pentaaza‐1‐azonia‐3‐phosphatricyclo[3.3.1.13,7]decane}. The arene‐ruthenium(II) complexes 4a–d and 5a and b are efficient catalysts for the redox isomerization of allylic alcohols into carbonyl compounds in both THF and aqueous media. The catalytic systems can be recycled by a simple extraction process and used in up to 4 consecutive runs. All the water‐soluble complexes prepared in this work are able to promote the cycloisomerization of (Z)‐enynols to afford furans in water, the best performance being obtained with the iridium catalyst 7b. Furthermore, 7b has shown an excellent recyclability (10 runs). This study represents the first example of iridium‐catalyzed cycloisomerization of (Z)‐enynols.
Diastereoselective Synthesis of α‐Oxyamines via Gold‐, Silver‐ and Copper‐Catalyzed, Three‐Component Couplings of α‐Oxyaldehydes, Alkynes, and Amines in Water
Authors: Huang Baosheng , Yao Xiaoquan , Li Chao‐Jun 
Published: August 2006

AbstractThe three‐component couplings of α‐oxyaldehydes, alkynes, and amines in water were investigated by using gold, silver and copper catalysts. Gold(I) was found to be the most effective catalyst in this reaction to afford propargylamines in good yields and moderate diastereoselectivities. On the other hand, silver catalysts show the best catalytic activities on non‐coordinating α‐alkyl‐substituted aldehydes.
Iron(III)–Zirconium(IV) Combined Salt Immobilized on N‐(Polystyrylbutyl)pyridinium Triflylimide as a Reusable Catalyst for a Dehydrative Esterification Reaction
Authors: Nakamura Yuka , Maki Toshikatsu , Wang Xiaowei , Ishihara Kazuaki , Yamamoto Hisashi 
Published: August 2006

AbstractN‐(Polystyrylbutyl)pyridinium triflylimide is prepared by a coupling reaction of commercially available 4‐bromobutyl‐polystyrene with pyridine and a subsequent anion exchange reaction with lithium triflylimide. This new polystyrene‐bound pyridinium salt is useful as a solid support to immobilize a zirconium(IV)–iron(III) binary metal complex, which is a homogeneous catalyst for the dehydrative ester condensation of an equimolar mixture of carboxylic acids and alcohols. The immobilized zirconium(IV)–iron(III) complex is easily recovered by filtration after complete esterification, and is reusable without any loss of activity.
Efficient Recycling in Suzuki–Miyaura Reactions of Aryl Chlorides with Arylboronic Acids using Polymer‐Supported Aryldicyclohexylphosphine
Authors: Glegoła Katarzyna , Framery Eric , Pietrusiewicz K. Michał , Sinou Denis 
Published: August 2006

AbstractThe synthesis of polymer‐supported aryldicyclohexylphosphines has been developed. The catalytic performance of these ligands has been demonstrated in the Suzuki–Miyaura cross‐coupling reaction of aryl chlorides with arylboronic acids. Concerning the recycling of the catalyst, the ligand based on copolymer polyethylene glycol/polystyrene showed a very high activity which was maintained during 6 runs.
Alkylation of Aldehydes with Trialkylboranes in Water
Authors: Hirano Koji , Yorimitsu Hideki , Oshima Koichiro 
Published: August 2006

AbstractWater enables the alkylation of aldehydes with trialkylboranes under nickel catalysis without the addition of a base. Trialkylboranes prepared from borane‐dimethyl sulfide and terminal olefins via hydroboration as well as commercially available trialkylboranes could be employed for the reaction. The reaction would proceed via η2‐coordinated nickel complexes with aldehydes as the key intermediates.
Cross‐Linked Aggregates of the Hydroxynitrile Lyase from Manihot esculenta: Highly Active and Robust Biocatalysts
Authors: Chmura Andrzej , van der Kraan Geert M. , Kielar Filip , van Langen Luuk M. , van Rantwijk Fred , Sheldon Roger A. 
Published: August 2006

AbstractThe precipitation and cross‐linking into CLEAs of the hydroxynitrile lyase (E.C. 4.1.2.10) from Manihot esculenta was investigated and an optimized procedure, which involved precipitation with (NH4)2SO4, was developed. It was found that a fast (photometric) assay severely underestimated the activity recovery in the CLEA due to rate‐limiting diffusion, whereas in a synthetic assay the activity recovery was up to 93 % of the starting activity. The CLEA was applied in the hydrocyanation of various aldehydes and ketones in microaqueous medium, conditions that rendered the non‐enzymatic background reaction insignificant, even with unreactive substrates.
Maximise Equilibrium Conversion in Biphasic Catalysed Reactions: How to Obtain Reliable Data for Equilibrium Constants?
Authors: Eckstein M. F. , Lembrecht J. , Schumacher J. , Eberhard W. , Spiess A. C. , Peters M. , Roosen C. , Greiner L. , Leitner W. , Kragl U. 
Published: August 2006

AbstractFor the prediction and optimisation of the equilibrium conversion in biphasic catalysed reactions, the equilibrium constant of the desired reaction and the partition coefficients of all reactants have to be known. Within this contribution we have examined the alcohol dehydrogenase‐catalysed reduction of several linear and aromatic ketones in biphasic reaction media with respect to equilibrium conversion. In this example, the equilibrium constant can be expressed in terms of differences in oxidation‐reduction potentials ΔE0. However, for a large variety of organic compounds, these data are quite rare in the literature. To overcome this lack of data, we have utilised methods of computational chemistry to calculate data for the Gibbs free energy ΔGR leading to the equilibrium constants of a homologous series of linear ketones. To obtain comparable data for the reduction of substituted acetophenone derivatives, the Hammett relation leads to the necessary equilibrium constants. Furthermore, we compare the equilibrium conversions of a set of cofactor regeneration methods for the alcohol dehydrogenase‐catalysed reductions. These results lead to a time‐saving experimental design for the enantioselective reduction of 2‐octanone to (R)‐2‐octanol on a preparative scale utilising biphasic reaction conditions.
Water‐Soluble Triphenylphosphane‐3,3′,3′′‐tricarboxylate (m‐TPPTC) Ligand and Methylated Cyclodextrins: A New Combination for Biphasic Rhodium‐Catalyzed Hydroformylation of Higher Olefins
Authors: Tilloy Sébastien , Genin Emilie , Hapiot Frédéric , Landy David , Fourmentin Sophie , Genêt Jean‐Pierre , Michelet Véronique , Monflier Eric 
Published: August 2006

AbstractThe methylated cyclodextrins/m‐TPPTC [tris(m‐carboxyphenyl)phosphane trilithium salt] couples proved to be more efficient than the well‐known methylated cyclodextrins/TPPTS [tris(m‐sulfonatophenyl)phosphane trisodium salt] systems in terms of activities and selectivities to perform the Rh‐catalyzed hydroformylation of higher olefins in an aqueous‐organic system. The interactions cyclodextrins/m‐TPPTC have been fully studied by NMR spectroscopy.