bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and Properties of Fluoroazulenes. II. Electrophilic Fluorination of Azulenes with N-Fluoro Reagents
Authors: Ueno Tetsuya , Toda Haruhiko , Yasunami Masafumi , Yoshifuji Masaaki 
Published: June 2006

Abstract
1-Fluoro- and 1,3-difluoroazulenes were synthesized for the first time by the electrophilic fluorination of azulenes with N-fluoro reagents. Selective preparation of 1-fluoroazulenes were performed by the fluorination of methyl azulene-1-carboxylates, followed by demethoxycarbonylation in 100% H3PO4. 2-Substituted azulenes were fluorinated in higher yields. In the 1H NMR of 1-fluoroazulene, long-range JFH values were not observed at H-2 and H-8, in contrast to those for 1-fluoronaphthalene. The 1-fluorine atom causes significant bathochromic shifts in the visible absorption of azulene, due to the so-called +Iπ effect.
Facilitated Photoreduction of Ruthenium Bis(4′-methylterpyridine) Pendant Myoglobin
Authors: Hamachi Itaru , Matsugi Tomoaki , Tanaka Shigeaki , Shinkai Seiji 
Published: June 2006

Abstract
A synthetic heme bearing ruthenium bis(terpyridine) through a covalent bond was successfully prepared. Ruthenium bis(terpyridine) pendant myoglobin, which was synthesized by a conventional cofactor reconstitution method, was efficiently activated through a photoinduced electron-transfer reaction from the ruthenium complex to the heme center. No reaction occurred in the corresponding intermolecular reaction system.
Conformational Preference in β-Aryldehydroalanine. Synthesis and Conformational Study of Tripeptides Containing β-Aryldehydroalanine Residues
Authors: Inai Yoshihito , Kurashima Shyu , Okado Yoshio , Hirabayashi Tadamichi , Yokota Kenji 
Published: June 2006

Abstract
In order to investigate the effect of bulky β-substituents on the conformational preference in α, β-dehydroamino acid residues, three kinds of tripeptides containing (Z)-β-phenyldehydroalanine, (Z)-β-(1-naphthyl)dehydroalanine, or (Z)-β-(1-pyrenyl)dehydroalanine residue were synthesized: Boc–Ala–ΔZAA–Val–OMe (Boc, t-butoxycarbonyl; Ala, L-alanine; ΔZAA, (Z)-β-aryldehydroalanine; Val, L-valine; OMe, methoxy). Their conformations in solution were investigated using 1H NMR spectroscopy. The solvent accessibility of the NH resonances and the nuclear Overhauser effect (NOE) indicated that the three peptides in CDCl3 form a type II β-turn conformation supported by hydrogen bonding between CO (Boc) and NH (Val). From a conformational energy calculation, the three kinds of ΔZAA residues were also shown to favor a type II β-turn conformation. In each β-turn, the orientation of the aryl plane was found to be non planar relative to the Cα=Cβ–Cγ plane, suggesting that a steric interaction between the β-aryl group and the peptide backbone leads to the internal rotation angles preferred for the β-turn backbone.
Comparison of the Efficiencies of the Fused Heterocyclic Compounds, 9H-Xanthene-2,7-diols, and Related Chain-Breaking Phenolic Antioxidants
Authors: Yamamura Tatsuo , Ishida Takafumi , Ueyama Hiroyuki , Hayashida Hirokazu , Ishimaru Takuya , Nishiyama Tomihiro 
Published: June 2006

Abstract
The antioxidant activities of 9H-xanthene-2,7-diols that are structurally related to tocopherols and 2,2′-alkylidenedi(hydroquinones) were measured by the inhibition of the thermally initiated autoxidation of tetralin at 60 °C using an oxygen-absorption method. The stoichiometric factors were calculated as n = 3.3—5.5 for 9H-xanthene-2,7-diols and 0.5—0.9 for 2,2′-alkylidenedi(hydroquinones) that lack the fused six-membered heterocyclic ring. Comparison of the alkyl substituent on the bridged methylene carbon showed that 9-methyl-9H-xanthene-2,7-diols increased in n value compared with 9-ethyl-9H-xanthene-2,7-diols. For the 9-methyl-9H-xanthene-2,7-diols, alkyl groups ortho to the phenolic hydroxyl group decreased the Rinh value: two methyl groups by 10-fold, one methyl group by 1.9-fold, and one t-butyl group by 1.4-fold, compared to that for the 9-methyl-9H-xanthene-2,7-diol. On the other hand, 2,2′-alkylidenedi(hydroquinones) were poorer antioxidants than the structurally comparable 9H-xanthene-2,7-diols. The low reactivity of 2,2′-alkylidenedi(hydroquinones) compared to those of 9H-xanthene-2,7-diols is attributed to electronic factors. The p-type lone pair on the hydroxyl oxygen can not help stabilizing the phenoxyl formed upon abstraction of the phenolic hydrogen.
Crystal Structure and Stereoselective Solid-State Photodimerization of 1-(9-Anthryl)alkyl Acetates
Authors: Mori Yukie , Horikoshi Yumiko , Maeda Koko 
Published: June 2006

Abstract
X-Ray structure analyses of 1-(9-anthryl)alkyl acetates [AnCH(OAc)R; An = 9-anthryl, R = Me (1a), Et (1b), i-Pr (1c), t-Bu (1d), CF3 (1e)] indicated that these molecules adopted similar conformations in which the bond connecting the chiral carbon and the substituent was oriented almost perpendicular to the anthracene plane. In the crystals of 1b—1e two adjacent anthracenes related by an inversion center was stacked with a short interplane distance (3.5—3.6 Å), which was favorable for the formation of the meso head-to-tail dimer. Photolysis of crystals of 1b, 1c, and 1e afforded meso-dimers in almost 100% yield, while 1d was photostable. The quantum yield of dimerization for 1b (0.16) was higher than that in solution. Although the dimerization did not proceed in single crystal-to-single crystal fashion, the observed high selectivity suggested that the reaction took place between the π-stacking pair even when the crystalline lattice of the monomer was destroyed. Irradiation of 1a—1e in benzene solution gave meso- and dl-head-to-tail dimers in a ratio of 1 : 1. The quantum yield of dimerization decreased with increase in the size of the substituent.
Synthesis and Properties of A–B–A Block Copoly(ester-ethers) Comprising Poly(l-lactide) (A) and Poly(oxypropylene-co-oxyethylene) (B) with Different Molecular Weights
Authors: Lee Chan Woo , Kimura Yoshiharu 
Published: June 2006

Abstract
An A–B–A triblock copoly(ester-ether) comprising poly(l-lactide) (A) and poly(oxyethylene-co-oxypropylene) (B) was prepared by copolymerization of l-lactide and a commercially available telechelic copolyether, Pluronic® (PN), with different molecular weights by the catalysis of tin(II) octanoate. The low molecular weight PN gave the copolymers having a low or medium molecular weight and a unit composition slightly different from the feed ratio. With PN whose molecular weight was around 10000, high molecular weight copolymers were obtained in high yield. For the PN with molecular weight of 8400, the block copolymerization was examined at different feed ratios, in which the molecular weight and the unit composition were successfully controlled by changing the l-lactide/PN ratio in feed. The copolymer containing 10 wt% of this PN was melt-spun into a filament, which was drawn to various draw ratios at 40 and 60 °C. The tensile modulus and strength of the filament increased with the draw ratio increasing at 60 °C, while at 40 °C they reached a plateau above the draw ratio of 5.0. It was found that the copolymer filaments showed an improved flexibility due to the incorporation of the soft PN segments. The in vitro hydrolysis test of the drawn filaments showed that the block copolymer has much higher degradability than the homo poly-l-lactide.
Review of Degradation Mechanisms Leading to Sludge and Varnish in Modern Turbine Oil Formulations
Authors: Fitch JC , Gebarin S 
Published: June 2006

Abstract
In recent years, there has been an unusually large number of reported cases associated with varnish and sludge formation in turbine-generator and compressor applications using Group II turbine oil formulations. Explanations for these problems have varied but typically include Group I/Group II incompatibility, additive instability, bulk oil oxidation, adiabatic compressive heating, electrostatic discharge, among others. This paper reviews these failure pathways and discusses actual case history including root cause analysis. Analytical methods for the sludge/varnish and the degraded oil are also reviewed.
Metabolic abnormalities in patients with normocalcemic hyperparathyroidism detected at a population-based screening
Authors: Hagström Emil , Lundgren Ewa , Rastad Jonas , Hellman Per 
Published: June 2006

Objective: Dyslipidemia, hypertension, diabetes mellitus and also primary hyperparathyroidism (pHPT) are associated with an increased risk of cardiovascular diseases. Metabolic abnormalities in mild pHPT have been reported, but never in cases with normal calcium and high parathyroid hormone (PTH) levels, i.e. suffering from ‘normocalcemic pHPT’. Our aim was to explore the occurrence of these metabolic abnormalities in individuals with normocalcemic pHPT identified in a population-based screening, and the effects of parathyroidectomy vs conservative treatment on metabolic variables.
Design and methods: A population-based screening of 5202 post-menopausal women identified 30 patients with normal calcium, inappropriately high PTH and normal creatinine. A 5-year follow-up included 15 parathyroidectomized (PTx) and nine conservatively followed cases, in a non-randomized setting, together with age-matched controls. Biochemical variables and body mass index (BMI) were investigated.
Results: At study entry, cases had higher calcium, PTH, glucose, low-density lipoprotein (LDL)/high-density lipoprotein (HDL)-cholesterol, very low-density lipoprotein (VLDL)-cholesterol, total triglycerides, and BMI compared to controls (P = < 0.0001–0.035). The cases had a lower HDL-cholesterol value (P = 0.013) and one third of the cases had hypertriglyceridemia. During follow-up, the PTx cases decreased in calcium, PTH, LDL/HDL-cholesterol, total and LDL-cholesterol (P = 0.0076–0.022). Investigated biochemical variables remained adverse in conservatively followed cases during follow-up except a decreased LDL-cholesterol value. All surgically treated patients had parathyroid adenoma.
Conclusions: Cases with normocalcemic pHPT have increased proatherogenic lipoprotein levels, BMI and glucose levels compared to age-matched controls. Parathyroidectomy has positive effects on some of these variables and reverses them to the same level as the controls, while conservative treatment fails to normalize the investigated metabolic variables.
Effects of the long-acting somatostatin analogue Lanreotide Autogel on glucose tolerance and insulin resistance in acromegaly
Authors: Steffin B , Gutt B , Bidlingmaier M , Dieterle C , Oltmann F , Schopohl J 
Published: June 2006

Object: Treatment with somatostatin analogues (SA) not only inhibits GH secretion but may also impair insulin secretion. In order to evaluate the influence of SA on glucose metabolism, we investigated insulin resistance (IR) and β-cell function, using the recommended combination of homeostatic model assessment of IR (HOMA-IR) and β-cell function (HOMA-β).
Design and methods: This is a prospective, cross-sectional study. We measured fasting insulin, blood glucose and IGF-I. Insulin and blood glucose measurements were taken 120 min after an oral glucose tolerance test with 75 g glucose. We studied 51 patients (27 female/24 male, age 54 years (20–75)). Eighteen patients were on Lanreotide Autogel (LA) treatment, 33 had no medical treatment. GH-levels of more than 2.5 ng/ml was reached by 59% of the patients, 74.5% had normal IGF-I levels.
Results: We found no significant influence of disease activity on HOMA-IR and HOMA-β. In the 33 of 51 subjects without any drug treatment, median HOMA-β was 170.4% (36.0–624.0%). In contrast, in the 18 patients on LA treatment, median HOMA-β was found to be significantly lower (84.2% (36.5–346.2%); P = 0.001). Despite this, there was no difference in HOMA-IR in both groups (2.4 (0.7–8.4) vs 2.3 (0.7–6.1); P < 0.001) despite similar insulin values.
Conclusion: In conclusion, we found that LA decreases β-cell function significantly without affecting IR. Therefore, we think that insulin secretagogues are probably more effective in the treatment of diabetes mellitus in acromegalic patients on LA therapy than insulin sensitizers.
Assessing 1-h plasma glucose and shape of the glucose curve during oral glucose tolerance test
Authors: Zhou Weibin , Gu Yanyun , Li Hong , Luo Min 
Published: June 2006

Objective: To assess the cutoff values at different time points for impaired glucose regulation (IGR) and diabetes, the glucose curve and isolated 1-h hyperglycemia were monitored during an oral glucose tolerance test (OGTT).
Methods: Two thousand eight hundred and eighty-six subjects (1300 men and 1586 women) were recruited to have an OGTT. Plasma was collected at 0, 30, 60, 120, and 180 min to analyze glucose and insulin. The diagnosis of impaired fasting glucose, impaired glucose tolerance, and diabetes was based on World Health Organization and American Diabetes Association’s criteria. Those with fasting plasma glucose (FPG)<5.6 and 2-h plasma glucose (PG)<7.8, but 1-h PG≥7.8 and <11.1 mmol/l were defined as 1h-High7.8, and those with FPG<7.0 and 2-h PG<11.1, but 1-h PG≥11.1 mmol/l as 1h-High11.1. The cutoff values were calculated by receiver operating characteristic (ROC) curve. The correlation between β-cell function and the area under the curve of glucose (AUCg) and the shape index was analyzed with linear regression.
Results: The cutoff values for IGR were 5.6, 9.7, 10.1, 7.8 and 6.1 mmol/l for blood glucose at 0, 30, 60, 120 and 180 min, 24 for AUCg and 1.3 mmol/l for the shape index. The cutoff values for diabetes were 6.8, 11.2, 13, 11.1 and 7 mmol/l for 0, 30, 60, 120 and 180 min, 30.9 for AUCg and 2 mmol/l for the shape index. Both AUCg and the shape index were inversely related to β-cell function. The profiles of glucose and insulin in the subgroup with isolated 1-h hyperglycemia were very different from those seen in subjects with normal glucose tolerance or IGR.
Conclusions: The present study provides new information on measures other than the fasting and 2-h PG to evaluate glucose metabolism in vivo and stimulates further research aimed at assessing the value of the OGTT 1-h PG concentration prospectively.
The effects of sex-steroid administration on the pituitary–thyroid axis in transsexuals
Authors: Bisschop Peter H , Toorians Arno W , Endert Erik , Wiersinga Wilmar M , Gooren Louis J , Fliers Eric 
Published: June 2006

Objective: Estrogen and androgen administration modulate the pituitary–thyroid axis through alterations in thyroid hormone-binding globulin (TBG) metabolism, but the effects of sex steroids on extrathyroidal thyroxine (T4) to triiodothyronine (T3) conversion in humans are unknown.
Design and methods: We studied 36 male-to-female and 14 female-to-male euthyroid transsexuals at baseline and after 4 months of hormonal treatment. Male-to-female transsexuals were treated with cyproterone acetate (CA) 100 mg/day alone (n=10) or in combination with either oral ethinyl estradiol (or-EE) 100 μg/day (n=14) or transdermal 17β-estradiol (td-E) 100 μg twice a week (n=12). Female-to-male transsexuals were treated with i.m. testosterone 250 mg twice a week. A t-test was used to test for differences within groups and ANOVAwith post hoc analysis to test for differences between the groups.
Results: Or-EE increased TBG (100 ± 12%, P<.001) and testosterone decreased TBG (−14 ± 4%, P =0.01), but free T4 did not change. Td-E and CA did not affect TBG concentrations. TSH was not different between groups at baseline or after treatment. CA decreased T3/T4 ratios (−9 ± 3%, P=0.04), suggesting that T4 to T3 conversion was lower. Testosterone increased T3/T4 ratios (30 ± 9%, P=0.02), which probably reflects higher T4 to T3 conversion.
Conclusion: Oral but not transdermal estradiol increases TBG, whereas testosterone lowers TBG. Testosterone increases T3/T4 ratios. Estradiol does not affect T3/T4 ratios, irrespective of the route of administration.
The androgen receptor CAG repeat modifies the impact of testosterone on insulin resistance in women with polycystic ovary syndrome
Authors: Möhlig Matthias , Jürgens Annette , Spranger Joachim , Hoffmann Kurt , Weickert Martin O , Schlösser Hans W , Schill Thilo , Brabant Georg , Schüring Andreas , Pfeiffer Andreas F H , Gromoll Jörg , Schöfl Christof 
Published: June 2006

Objective: Hyperandrogenism is a central feature of the polycystic ovary syndrome (PCOS) and might worsen insulin resistance (IR) often seen in PCOS. Androgens act through the androgen receptor (AR). A polymorphic CAG repeat sequence within the AR gene was reported to modulate its transactivation activity. Therefore, we investigated a putative interaction between testosterone and the CAG repeat length polymorphism with respect to IR.
Design: In 63 PCOS women with normal glucose tolerance free testosterone, the biallelic CAG repeat length and a multiplicative interaction term were investigated by multiple linear regression analysis for an association with IR as indicated by the homeostasis model assessment of IR (HOMA-IR).
Results: Free testosterone was correlated with HOMA-IR. The impact of testosterone on HOMA-IR was modified by the AR CAG length as indicated by an interaction term. This interaction remained significant after adjustment for smoking, age and body mass index. While there was a positive association of free testosterone with HOMA-IR, the interaction term was inversely associated. The model, which explained 42.5% of the variation of HOMA-IR predicted that in carriers of short CAG lengths, an increase in testosterone increased IR. This effect attenuated with rising biallelic CAG length until it turns into the opposite at a CAG length longer than 23. The results were confirmed by using CIGMA as another measure of IR.
Conclusions: The association between testosterone and IR is modified by the CAG repeat polymorphism within the AR. Therefore, the evaluation of testosterone effects on IR seems to require consideration of the AR CAG repeat polymorphism in PCOS women.
Post-Transplant Lymphoproliferative Disorders
Authors: LaCasce Ann S. 
Published: June 2006

Learning Objectives
After completing this course, the reader will be able to: Discuss the incidence and pathologic classification of PTLD.Define the etiology and risk factors for PTLD.Discuss the presenting clinical features and diagnostic evaluation of PTLD.Describe treatments and reported outcomes for PTLD.
Access and take the CME test online and receive 1 AMA PRA category 1 credit at CME.TheOncologist.com
Low-Grade Gliomas in Adults
Authors: Grier Jeanine T. , Batchelor Tracy 
Published: June 2006

Learning Objectives
After completing this course, the reader will be able to: Discuss the incidence of low-grade gliomas and list the various diagnostic methods employed for this group of tumors.Identify the factors that influence treatment decisions and the various treatment options available for low-grade gliomas.Outline the evidence regarding resection, radiation, and chemotherapy for the treatment of low-grade gliomas.List the specific subsets of low-grade glioma and the unique diagnostic, prognostic, and treatment factors associated with each subset.Describe the different treatment-related complications that are relevant for the low-grade glioma patient population.
Access and take the CME test online and receive 1 AMA PRA category 1 credit at CME.TheOncologist.com
Viscosities for Completion Fluids at Temperature and Density
Authors: Ortego Anne M. , Vollmer Daniel P. 
Published: June 2006

SummaryBrine viscosities are an important property in sand-control and coil-tubing operations. Viscosities are used to calculate sand settling rates for gravel- packing and frictional pressure losses. Because of limited brine-viscosity data, viscosites were determined for conventional completion fluids using an Oswald viscometer. Then, 3D equations were determined as a function of density and temperature for calcium chloride; calcium bromide; calcium chloride and calcium bromide; calcium bromide and zinc bromide; three-salt mixture of calcium chloride, calcium bromide, and zinc bromide; and sodium bromide solutions. All equations had an absolute average deviation from the measured values of less than 10%.
The Effect of the Synthetic- and Oil-Based Drilling Fluid&apos;s Internal Water-Phase Composition on Barite Sag
Authors: Omland Tor Henry , Albertsen Tron , Taugbøl Knut , Saasen Arild , Svanes Kåre , Amundsen Per Amund 
Published: June 2006

Summary
One important issue for drilling operations is control of downhole pressures. When drilling with synthetic- or oil-based drilling fluids, the ability to maintain all the weighting agents in suspension is particularly difficult because these fluids are more vulnerable toward sag than water-based drilling fluids.
In the current study, it will be shown that the ability to keep barite in suspension also depends on the chemical composition of the water phase. The sag tendency of a mineral-oil-based drilling fluid, a linear paraffin-based drilling fluid, and both an ester- and a linear-alpha-olefin (LAO) -based synthetic drilling fluid has been evaluated. For comparison, all fluids were formulated with equivalent water activity in the internal brine phase. The results show that for all these fluids, improved performance was observed if the traditional calcium chloride (CaCl2) salt was replaced with a selection of other salts. Formates as the internal salt gave generally better performance than if calcium chloride was used. The best stability in the tests was observed using an ammonium calcium nitrate [NH4Ca(NO3)] as the internal salt phase, which also enhances the environmental performance of the fluid.
This paper describes in detail the effect that different salts in the internal brine phases in synthetic- and oil-based drilling fluids had on sag performance in a series of tests.
Controlled Mud-Cap Drilling for Subsea Applications: Well-Control Challenges in Deep Waters
Authors: Fossli Børre , Sangesland Sigbjørn 
Published: June 2006

Summary
This paper describes a new drilling-riser concept and drilling methodology for deepwater operations that will remove some of the well-control challenges and limitations currently experienced when handling kicks and deep gas influxes in deepwater regions, with the following results:
Providing improved and more flexible well-control procedures. Reducing the potential of hydrate plug formation during well-control operations. Allowing for drilling longer hole sections than normally considered feasible when using conventional drilling methods, thus reducing the number of casing strings required in the well. Allowing for improved drilling performance in depleted formations.
The main elements in the system are based on using a small, high-pressure drilling riser [14-in. outer diameter (OD), 12.5-in. inner diameter (ID)] with a split surface/subsea blowout preventer (BOP) and a subsea mud-lift pump connected to the drilling riser and a separate mud-return line.
During drilling and well-control operations, the mud level in the riser is maintained considerably below sea level to create a mud/air interface (i.e., a &quot;mud cap??) that can be continuously adjusted up or down by the mud-lift pumping system. As a consequence, the bottomhole hydrostatic pressure will be controlled. One of the main purposes of this system is to mitigate the inherent problems with a conventional 21-in.-OD marine drilling riser during well-control scenarios in deepwater operations. The system will compensate for frictional pressures resulting from circulation and adjust the bottomhole pressure (BHP) accordingly.