bluuebunny/crossref_metadata_2025_split huggingface dataset:
Glycosylation of Vitamin E Homologue by Cultured Plant Cells
Authors: Kondo Yoko , Shimoda Kei , Takimura Junichi , Hamada Hatsuyuki , Hamada Hiroki 
Published: March 2006

Abstract
Biotransformation of 2,2,5,7,8-pentamethyl-6-chromanol (vitamin E homologue) was investigated with cultured plant cells of Phytolacca americana, Catharanthus roseus, and Eucalyptus perriniana. The cultured cells of P. americana converted 2,2,5,7,8-pentamethyl-6-chromanol into its β-glucoside, whereas conversion with C. roseus and E. perriniana also afforded the hydrolysis product of β-glucoside and a new β-gentiobioside product, i.e., 2,2,5,7,8-pentamethylchroman-6-yl 6-O-β-d-glucopyranosyl-β-d-glucopyranoside.
Preparation of Novel Eu-doped Titanate Nanotube Phosphor
Authors: Chi Bo , Victorio Erick S , Jin Tetsuro 
Published: March 2006

Abstract
A novel titanate nanotube phosphor doped with Eu was synthesized through a facile hydrothermal treatment method. The multilayered nanotubes have an outer diameter of 12 nm and inner diameter of 4 nm, with a BET surface area of 225 m2·g−1. The nanotube was identified to have a monoclinic layered titanate structure. The Eu-doped nanotube exhibits luminescent property that is slightly different from the corresponding nanopowder.
New Charge-transfer Salts Based on Unsymmetrical Donor DMET and Metal Complex Anions: (DMET)3[Cr(isoq)2(NCS)4] and (DMET)3[Cr(phen)(NCS)4]·CH3CN
Authors: Umemiya Masamichi , Goto Makoto , Kobayashi Norihito , Takaishi Shinya , Kajiwara Takashi , Yamashita Masahiro , Miyasaka Hitoshi , Sugiura Ken-ichi , Watanabe Harutaka , Suzuki Daichi , Ito Hiroshi , Kuroda Shin-ichi 
Published: March 2006

Abstract
Two charge-transfer salts (DMET)3[Cr(isoq)2(NCS)4] (1) and (DMET)3[Cr(phen)(NCS)4]·CH3CN (2) have been prepared and characterized. The single-crystal X-ray crystallography revealed that the structures of both salts consist of segregated columns of DMET and metal complex anions. The magnetic and transport properties have shown that these salts are paramagnetic semiconductors.
Sulfenylphosphinoferrocenes: Novel planar chiral ligands in enantioselective catalysis
Authors: Cabrera Silvia , García Mancheño Olga , Gómez Arrayás Ramón , Alonso Inés , Mauleón Pablo , Carretero Juan C. 
Published: March 2006

Abstract
Structurally well-defined transition-metal complexes of 1-phosphino-2-sulfenylferrocene (Fesulphos ligands) act as highly efficient catalysts in a variety of mechanistically different transformations. Excellent enantioselectivities were achieved in Pd-catalyzed allylic substitutions, desymmetrization of meso-heterobicyclic alkenes by Pd-catalyzed addition of dialkylzinc reagents, Pd-catalyzed Diels-Alder reaction of cyclopentadiene with N-acryloyl oxazolidinones, and in Cu-catalyzed formal aza-Diels-Alder reaction of Danishefsky diene to N-sulfonyl aldimines.
Catalytic asymmetric addition reactions leading to carbon-carbon bond formation: Phenyl and alkenyl transfer to aldehydes and alkynylation of α-imino esters
Authors: Ji Jian-Xin , Wu Jing , Xu Lijin , Yip Chiu-Wing , Lam Kim Hung , Chan Albert S. C. 
Published: March 2006

Abstract
Optically active tertiary aminonaphthol ligands were obtained by a new, convenient procedure and were found to catalyze the enantioselective alkenyl and phenyl transfer to aldehydes in high yields and excellent enantiomeric excesses (ee's). The catalytic asymmetric introduction of alkynyl functionality to α-amino acid derivatives was realized by the direct addition of terminal alkynes to α-imino ester in the presence of chiral copper(I) complex under mild reaction conditions.
Development of homogeneous and heterogeneous asymmetric catalysts for practical enantioselective reactions
Authors: Ding Kuiling 
Published: March 2006

Abstract
Two strategies for the development of practical asymmetric catalysis have been discussed in this article. The first part of this article focuses on the design and screening of highly efficient and enantioselective chiral catalysts for asymmetric hydrogenation reactions employing combinatorial approach. The second part presents a conceptually new strategy (i.e., "self-supporting" approach) for the immobilization of homogeneous catalysts through assembly of chiral multitopic ligands and metal ions without using any support. The success of this strategy will be exemplified in heterogeneous asymmetric carbonyl-ene, sulfoxidation, and epoxidation, as well as in asymmetric hydrogenation reactions.
Rhodium-catalyzed asymmetric reactions with a dynamic library of chiral tropos phosphorus ligands
Authors: Gennari Cesare , Monti Chiara , Piarulli Umberto 
Published: March 2006

Abstract
Nineteen chiral tropos phosphorus ligands, based on a flexible (tropos) biphenol unit and a chiral P-bound alcohol (11 phosphites) or secondary amine (8 phosphoramidites), were screened, individually and as a combination of two, in various Rh-catalyzed asymmetric reactions. In the Rh-catalyzed asymmetric conjugate addition of phenylboronic acid to cyclic enones, enantiomeric excesses (ee's) up to 95 % were obtained with a 1:1 mixture of a phosphite [derived from (1R,2S)-2-(1-methyl-1-phenylethyl)cyclohexanol] and a phosphoramidite [derived from (S,S)-2,5-diphenylpyrrolidine]. In the mixed Rh precatalyst, which was characterized via 31P-NMR, the biphenol-derived phosphite is free to rotate (tropos) while the biphenol-derived phosphoramidite shows a temperature-dependent tropos/atropos behavior (coalescence temperature = 310 K). The ligands were also screened in the hydrogenation of dehydro-α-amino acids and dehydro-β-amino acids. Ee's up to 98% were obtained for the dehydro-α-amino acids, using the combination of a phosphite [derived from (1R,2S)-2-phenyl-1-cyclohexanol] and a phosphoramidite [derived from (S,S)-bis(α-methylbenzyl)amine]. The reaction was optimized by lowering the phosphite/phosphoramidite ratio to 0.25:1.75 with a resulting improvement of the product ee.
Syntheses and reactions of optically active α-aminoallenylstannanes and α-aminopropargylboranes
Authors: Hegedus Louis S. , Ranslow Peter , Achmatowicz Michal , de los Rios Cristobal , Hyland Christopher , Garcia-Frutos Eva M. , Salman Sarri 
Published: March 2006

Abstract
An efficient synthesis of α-aminoallenylstannane from propargyloxazolidinone has been developed. It undergoes reaction with aldehydes to give homopropargylic alcohols with high syn selectivity. Epoxides undergo a similar reaction preceded by rearrangement to the aldehyde. These alcohols were used in the synthesis of β-amino acids, azasugars, and deoxyaminohexoses. Imines underwent reaction with this stannane to give 1,2-diamines. The related propargylborane reacts with aldehydes to produce allenyl carbinols. The Co2(CO)6 complexes of propargyloxazolidinones were developed as an α-aminopropargyl cation equivalent.
Palladium-catalyzed ring-forming reactions: Methods and applications
Authors: Lautens Mark , Alberico Dino , Bressy Cyril , Fang Yuan-Qing , Mariampillai Brian , Wilhelm Thorsten 
Published: March 2006

Abstract
Several Pd-catalyzed cyclization methods were developed, including norbornene-mediated Catellani-type reactions, a Pd-catalyzed coupling reaction of aryl iodides and allyl moieties, and a tandem C-N/C-C coupling of gem-dihalovinyl systems. These ring-forming methods were applied to the synthesis of highly functionalized carbocyclic and heterocyclic compounds. Intermolecular Pd-catalyzed methods for synthesis of highly substituted arene compounds were also developed.
Synthesis and reactivity of new strained cyclic allene and alkyne precursors
Authors: Peña Diego , Iglesias Beatriz , Quintana Iago , Pérez Dolores , Guitián Enrique , Castedo Luis 
Published: March 2006

Abstract
The synthesis of ortho-(trimethylsilyl)vinyl triflates is described. Fluoride-induced decomposition of these triflates leads to the generation of strained cycloallenes and cycloalkynes under mild reaction conditions. The generation rate of these highly reactive intermediates can be modulated by modifying the solubility of the fluoride source. The slow generation of cyclic allenes and alkynes is a prerequisite for their use in homogeneous catalysis.
Acid-base catalysis using chiral palladium complexes
Authors: Sodeoka Mikiko , Hamashima Yoshitaka 
Published: March 2006

Abstract
Chiral Pd aqua and µ-hydroxo complexes were found to act as mild Brønsted acids and bases, and chiral Pd enolates were generated from these complexes even under acidic conditions. Highly enantioselective Michael addition, Mannich-type reaction, fluorination, and conjugate addition of amines have been developed based on the acid-base character of these Pd complexes.
Influence of Sample Type and Storage Conditions on Soluble CD40 Ligand Assessment
Authors: Weber Michael , Rabenau Birgitt , Stanisch Michael , Elsaesser Albrecht , Mitrovic Vesselin , Heeschen Christopher , Hamm Christian 
Published: March 2006

Abstract
Background: Several studies have consistently shown that soluble CD40 ligand (sCD40L) concentrations are increased in patients with acute coronary syndromes and can serve as a biomarker for risk stratification. However, few data are available on preanalytic conditions that impact sCD40L values. Thus, the aim of our prospective study was to evaluate the impact of sampling techniques and storage conditions on sCD40L concentrations.
Methods: We included a total of 30 patients with no, stable, or unstable coronary heart disease. Blood samples were collected in gel-filled tubes without additives, in EDTA-filled tubes, and in citrate-filled tubes and were kept at various storage conditions.
Results: Median (interquartile range) sCD40L values at baseline were higher in serum samples [5.29 (3.89–6.33) μg/L] than in either EDTA plasma [0.78 (0.39–1.12) μg/L; P &lt;0.001] or citrate plasma [0.37 (0.22–0.51) μg/L; P &lt;0.001]. Serum values increased with delayed processing [7.94 (5.97–9.62) μg/L after 1.5 h (P &lt;0.001) vs baseline; 10.55 (7.58–11.55) μg/L after 3 h (P &lt;0.001) vs baseline]. However, after centrifugation, sCD40L values remained stable for all 3 sample types.
Conclusion: Plasma, but not serum, samples are appropriate for sCD40L measurements. In general, preanalytic conditions are critical in the assessment of sCD40L concentrations and thus should be carefully considered for future studies.
Stability constants of technetium(IV) oxalate complexes as a function of ionic strength
Authors: Xia Yuanxian , Hess Nancy J. , Felmy Andrew R. 
Published: March 2006

SummarySolvent extraction method was used to determine the stability constants of Tc(IV) with oxalate anions in NaCl solutions ranging in concentration from 0.5 M to 2.0 M. All experiments were conducted in an atmosphere-controlled chamber under Ar atmosphere (<1.0 ppm O2). A reducing agent (hydrazine) was used during extractions to maintain technetium in the tetravalent oxidation state. Independent tests confirmed that the oxidation state of technetium did not change during extractions. The distribution ratio of Tc(IV) between the organic and aqueous phases was found to decrease as the concentration of oxalic acid increased. At the oxalic acid concentrations used in these experiments, the complexes TcO(Ox) and TcO(Ox)22-were found to be the dominant aqueous species. Based on these data, the thermodynamic stability constants of Tc(IV) with oxalate complexes were calculated by the Specific Ion Interaction Theory (SIT).
Efficient preparation of 6-[18F]fluoroveratraldehyde, the precursor of the multi-step synthesis of [18F]FDOPA
Authors: Al-Labadi A. , Zeller K.-P. , Machulla H.-J. 
Published: March 2006

Summary
As a clinically well established PET tracer, 6-[18F]fluoro-L-dopa is prepared by a multi-step synthesis if [18F]fluoride is to be used for labelling. The [18F] label is introduced in the first step, i.e. 6-[18F]fluoroveratraldehyde is prepared first with yields reported in the literature ranging between 20 and 50%. To obtain higher over-all yields in the synthesis of 6-[18F]fluoro-L-dopa, the 18F incorporation in the first step was optimised by determining the yield dependencies on solvent, concentration of the precursor, temperature and time of the reaction. Thus, the product is formed with a yield of 89 ± 2% (n = 15) when using 20 mg of 6-nitroveratraldehyde in 1 mL DMF at 140 °C within a reaction time of 10 min.
Direct labeling of isoniazid with technetium-99m for diagnosis of tuberculosis
Authors: Roohi Samina , Mushtaq A. , Jehangir M. , Malik Salman A. 
Published: March 2006

SummaryIsonicotinic acid hydrazide (isoniazid) is one of the most effective agents in tuberculosis therapy. Hence it was chosen as ligand for99mTc labeling and imaging in the developed animal model with a gamma camera. Direct labeling of isoniazid with technetium-99m was studied. Factors affecting the radiolabeling efficiency such as amount of reducing agent, pH and time of the reaction were studied. Biodistribution of the labeled compound was performed in Sprague–Dawley rats. The localization kinetics of the radiolabeled complex was also studied in the developed animal model by injecting 100–125 MBq99mTc-isoniazid intravenously in the ear of rabbit and the images were taken with a gamma camera. Optimum conditions gave > 98% labeling efficiency of99mTc-isoniazid. Biodistribution studies in rats revealed that the maximum uptake was in kidneys (15%, 8% and 2.5% at 0.5, 4 and 24 hours, respectively), indicating renal excretion of the99mTc-isoniazid. High accumulation was obtained in liver (10%, 11% and 4% at 0.5, 4 and 24 hours, respectively) and significant radioactivity was also seen in the intestines (8%, 6% and 1% at 0.5, 4 and 24 hours, respectively), indicating hepatobiliary excretion of the complex. Less than 2% uptake in stomach until 24 hours confirmed goodin vivostability of the complex.99mTc-isoniazid initially accumulated in infective lesions ofS. aureusin rabbits due to hyper-vascularity, but because of its non specificity forS. aureusthe residency of99mTc-isoniazid was low and it showed rapid wash out from the lesion, whereas residency of tubercular lesion was high and it remained in the tubercular lesion in the delayed images also. The results suggest that99mTc-isoniazid is a specific agent for localization of tubercular lesions.
Assessment of air quality of two metropolitan cities in Pakistan: Elemental analysis using INAA and AAS
Authors: Waheed Shahida , Rahman A. , Khalid N. , Ahmad Shujaat 
Published: March 2006

Summary
For the assessment of air quality of two cities in Pakistan, Instrumental Neutron Activation Analysis (INAA) and Atomic Absorption Spectrometry (AAS) have been used. In all 26 elements were determined in suspended particulate matter (SPM) and soil samples. The SPM levels from different locations of Rawalpindi and Lahore indicate unhealthy to hazardous air quality much above the World Health Organization (WHO) guidelines. Metrological conditions and nature of soil that contains clay components mainly contribute to the inventory of the SPM elements of these cities. The calculated enrichment factors (EF) also indicate the dominance of the soil components. Contributions of inorganic elements due to heavy traffic with automotive exhaust and other commercial activities in this area have been identified. Areas of Qurtaba Chowk and Bank Square in Lahore in particular showed high EF for lead depicting burning of the automotive fuel and road dust. The accuracy and precision of the work has been maintained through the concurrent use of IAEA Reference Materials.
Geographical distribution of 90Sr contamination in Poland
Authors: Gaca Pawel , Skwarzec Bogdan , Mietelski Jerzy W. 
Published: March 2006

Summary
The paper presents results on determination of 90Sr in bilberry and cowberry leaves (Vaccinium myrtillus and Vaccinium vitis-idaea) and the use of these plants as bio-monitors of radiostrontium contamination in Poland. Radiostrontium was determined by mean of liquid scintillation spectrometry preceded by radiochemical separation using Sr-resin and 85Sr tracer. The approximate map of 90Sr contamination of Poland is presented. The activity ratio between 90Sr and obtained earlier data for 137Cs in the same samples is discussed. The enhancement of radiostrontium content observed in northeastern Poland seems to be the trace of hot-particles fallout from initial Chernobyl cloud, which passed over Polish territory toward Scandinavia.
Patterns of Distribution and Abundance of Tubifex tubifex and Other Aquatic Oligochaetes in Myxobolus cerebralis Enzootic Areas in Pennsylvania
Authors: Kaeser Adam J. , Sharpe William E. 
Published: March 2006

Abstract
Recent outbreaks of whirling disease (caused by the myxosporean parasite Myxobolus cerebralis) among wild rainbow trout Oncorhynchus mykiss have called attention to deficiencies in the knowledge of aquatic oligochaete ecology in rivers and streams of North America. Revealing the patterns of distribution and abundance of Tubifex tubifex, an obligate host in the life cycle of M. cerebralis, is critical to understanding local and regional differences in the epizootiology of this disease. To gather fundamental information on the ecology of T. tubifex among streams in Pennsylvania, we surveyed oligochaetes and the features of their habitat. We used indirect and direct ordination techniques to search for patterns in oligochaete assemblages and their relationships to the environment. In general, higher-gradient streams with coarse substrate contained low-density oligochaete assemblages dominated by the family Enchytraeidae. Lower-gradient streams with fine-sediment habitat were dominated by Limnodrilus hoffmeisteri and contained either Ilyodrilus templetoni or T. tubifex. A key finding to emerge from this survey was that high oligochaete density, T. tubifex occurrence, and T. tubifex density were associated with proximity to obvious sources of organic enrichment. Limits on the distribution of T. tubifex in Pennsylvania relative to distributions in M. cerebralis–affected systems in the Intermountain West may be a factor in explaining why whirling disease has not been observed to cause population declines among wild rainbow trout in this region and should be further investigated.
The Asymptotic Efficiency of Largest Claims Reinsurance Treaties
Authors: Kremer Erhard 
Published: March 2006

AbstractReinsurance treaties defined as generalizations of the classical largest claims reinsurance covers are investigated with respect to the associated risk, defined as the variance of the insurer's retaining total claims amount. Instead of the unhandy variance corresponding handier asymptotic expressions are used. With these an asymptotic efficiency measure for comparing two such reinsurance covers is defined. It is shown that with respect to asymptotic efficiency the excess-of-loss treaty is better than the classical largest claims treaty. Furthermore the problem of giving optimal wheights to the ordered claims of a generalized largest claims cover is discussed.
Fuzzy Insurance
Authors: Lemaire Jean 
Published: March 2006

AbstractFuzzy set theory is a recently developed field of mathematics, that introduces sets of objects whose boundaries are not sharply defined. Whereas in ordinary Boolean algebra an element is either contained or not contained in a given set, in fuzzy set theory the transition between membership and non-membership is gradual. The theory aims at modelizing situations described in vague or imprecise terms, or situations that are too complex or ill-defined to be analysed by conventional methods. This paper aims at presenting the basic concepts of the theory in an insurance framework. First the basic definitions of fuzzy logic are presented, and applied to provide a flexible definition of a “preferred policyholder” in life insurance. Next, fuzzy decision-making procedures are illustrated by a reinsurance application, and the theory of fuzzy numbers is extended to define fuzzy insurance premiums.
Asset Pricing Models and Insurance Ratemaking
Authors: Cummins J. David 
Published: March 2006

AbstractThis paper provides an introduction to asset pricing theory and its applications in non-life insurance. The first part of the paper presents a basic review of asset pricing models, including discrete and continuous time capital asset pricing models (the CAPM and ICAPM), arbitrage pricing theory (APT), and option pricing theory (OPT). The second part discusses applications in non-life insurance. Among the insurance models reviewed are the insurance CAPM, discrete time discounted cash flow models, option pricing models, and more general continuous time models. The paper concludes that the integration of actuarial and financial theory can provide major advances in insurance pricing and financial management.
Convergence of Bayes and Credibility Premiums
Authors: Schmidt Klaus D. 
Published: March 2006

AbstractFor a risk whose annual claim amounts are conditionally i.i.d. with respect to a risk parameter, it is known that the Bayes and credibility premiums are asymptotically optimal in terms of losses. In the present note it is shown that the Bayes and credibility premiums actually converge to the individual premium.
Minimax Estimation of a Mean Vector for Distributions on a Compact Set
Authors: Dykstra Richard 
Published: March 2006

AbstractMinimax estimation procedures for the mean vector of a distribution on a compact set under squared error type loss functions are considered. In particular, a Dirichlet process prior is used to show that a linear function of is a minimax estimator in the class of all measurable estimators and all possible distributions. This effort extends some earlier work of Bühlmann to a more general setting.
On Changing the Parameter of Exponential Smoothing in Experience Rating
Authors: Bonsdorff Heikki 
Published: March 2006

AbstractWe consider exponential smoothing Yn = αXn + (1 − α)Yn−1, 0 < α < 1, in experience rating. Here the premium Yn is determined by the policy's own claims history (Xn). In order to uniformize the fluctuation of premiums, it is appropriate to use a bigger α for the big policies than for the small ones. When the size of the policy changes with time, a need arises to change α correspondingly. It has recently been shown that changing based on the size of the premiums Yn may lead to too low a tariff level. This result is presented here and illustrated by means of simulation. Further, some general results are given how the changing can be made without a decline in the tariff level. The results are applied to a tariff system in which the linking of the smoothing parameter to the size of the policy is particularly motivated.
Bayes and Empirical Bayes Estimation for the Chain Ladder Model
Authors: Verrall R.J. 
Published: March 2006

AbstractThe subject of predicting outstanding claims on a porfolio of general insurance policies is approached via the theory of hierarchical Bayesian linear models. This is particularly appropriate since the chain ladder technique can be expressed in the form of a linear model. The statistical methods which are applied allow the practitioner to use different modelling assumptions from those implied by a classical formulation, and to arrive at forecasts which have a greater degree of inherent stability. The results can also be used for other linear models. By using a statistical structure, a sound approach to the chain ladder technique can be derived. The Bayesian results allow the input of collateral information in a formal manner. Empirical Bayes results are derived which can be interpreted as credibility estimates. The statistical assumptions which are made in the modelling procedure are clearly set out and can be tested by the practitioner. The results based on the statistical theory form one part of the reserving procedure, and should be followed by expert interpretation and analysis. An illustration of the use of Bayesian and empirical Bayes estimation methods is given.