bluuebunny/crossref_metadata_2025 huggingface dataset:
The epidemiology of the primary systemic vasculitides in northwest Spain: Implications of the Chapel Hill Consensus Conference definitions
Authors: Gonzalez‐Gay Miguel A. , Garcia‐Porrua Carlos , Guerrero Jose , Rodriguez‐Ledo Pilar , Llorca Javier
Published: June 2003

Objective

To assess the epidemiology of the primary systemic vasculitides (PSV) in a well‐defined population of southern Europe over a 14‐year period using the Chapel Hill Consensus Conference (CHCC) definitions.

Methods

The case records of all patients 15 years or older with vasculitis diagnosed between January 1988 and December 2001 at a single reference hospital in the Lugo region of northwest Spain were reviewed. Incidence rates were age‐ and sex‐adjusted to the European standard population. Patients were classified as having PSV according to the CHCC definitions.

Results

Fifty‐four Lugo residents (29 men) fulfilled the CHCC definitions for PSV. The mean age was 60.7 ± 13.5 years (men: 61.0 ± 13.4; women: 60.4 ± 13.8 years). The overall annual incidence of PSV was 13.07/million (95% confidence interval [95% CI] 8.89–19.22). PSV were slightly more common in men. The age‐specific incidence showed a clear increase with age. A peak in the 55–64 year age group for the whole group of patients with PSV was observed (34.9/million; 95% CI 28.6–42.6). Nonrandom periodical peaks of incidence every 3 years were only observed when the group of PSV was considered as a whole (P = 0.040). The annual incidence was 2.95/million (95% CI 1.44–6.05) for Wegener's granulomatosis (WG) and 7.91/million (95% CI 4.74–13.20) for microscopic polyangiitis (MPA) (P = 0.035). None of the patients with Churg Strauss syndrome (n = 4) lived in a rural area.

Conclusion

Our observations support an increasing incidence of PSV with age. In patients from northwest Spain defined by the CHCC definitions, MPA is more common than WG.
A comparison of self‐reports of distress and affective disorder diagnoses in rheumatoid arthritis: A receiver operator characteristic analysis
Authors: McQuillan Julia , Fifield Judith , Sheehan T. Joseph , Reisine Susan , Tennen Howard , Hesselbrock Victor , Rothfield Naomi
Published: June 2003

Objective

To compare 3 commonly used psychiatric symptom checklists (the Center for Epidemiological Studies Depression Scale [CES‐D], the Positive and Negative Affect Schedule, and the Endler Multidimensional Anxiety Scales [EMAS]) to determine their sensitivity, specificity, and ability to discriminate between a disorder (Major Depression [MD], Generalized Anxiety Disorder [GAD]), and no disorder. To compare the checklists for their ability to discriminate between type of disorder (MD and GAD). To evaluate the discriminant ability of the subscales, particularly positive affect; whether the somatic items in the CES‐D artificially inflate affective scores; and the optimal cut off score for the CES‐D.

Methods

We compared the 3 scales to diagnostic criterion of MD, GAD, and comorbid disorder using receiver operator characteristic (ROC) and logistic regression analyses. The sample consisted of a national panel of 415 individuals with rheumatoid arthritis (RA).

Results

Each of the scales had high sensitivity and specificity (areas under the curve: CES‐D = 0.92, negative affect = 0.88, positive affect and EMAS = 0.82). The CES‐D, however, demonstrated better sensitivity and specificity than the positive affect and the EMAS, but not the negative affect scale.

Conclusion

All 3 self‐reports have high combined sensitivity and specificity as measures of affective disorders among RA patients.
Bacterial components in the synovial tissue of patients with advanced rheumatoid arthritis or osteoarthritis: Analysis with gas chromatography‐mass spectrometry and pan‐bacterial polymerase chain reaction
Authors: Chen Tong , Rimpiläinen Marja , Luukkainen Reijo , Möttönen Timö , Yli‐Jama Tuomas , Jalava Jari , Vainio Olli , Toivanen Paavo
Published: June 2003

Objective

To study the presence of bacterial components in the synovial tissue (ST) of patients with advanced rheumatoid arthritis (RA).

Methods

ST was collected during joint surgery from 41 RA patients. Tissue from 39 patients with osteoarthritis (OA), 4 patients with undifferentiated inflammatory arthritis (UA), and 3 cases of accidental deaths served as controls. The pan‐bacterial polymerase chain reaction (PCR) with primers for the 23S ribosomal RNA (rRNA) and 16S rRNA genes was used to detect bacterial DNA. In addition, synovial fluid (SF) samples from patients with chlamydial reactive arthritis (ReA) were also examined by the same method. The positive controls, bacterial DNA or ST spiked with different living bacteria, were analyzed alongside clinical samples. Most of the ST samples were also analyzed by gas chromatography‐mass spectrometry (GC‐MS) for determining the presence of bacteria‐derived muramic acid. Strict precautions were followed in the clinics and the laboratory to prevent contamination.

Results

In GC‐MS analysis, muramic acid was observed in the ST from 4 of 35 RA patients and from 2 of 14 OA patients, but not in ST from 2 patients with UA and 3 cadavers. Bacterial DNA was not detected by either one of the PCR primers used in ST from 42 patients with RA and 39 patients with OA. However, 5 of 15 SF samples from ReA patients were PCR positive. The sensitivity of GC‐MS to detect muramic acid was 2 pg/injected amount (227 pg muramic acid/mg ST), and that of the pan‐bacterial PCR was 2–20 bacteria colony forming units/reaction.

Conclusion

These results indicate that a bacterial component, muramic acid, is detectable by GC‐MS in ST from a few patients with advanced RA or OA. However, no bacterial DNA was detectable by PCR.
Effects of disease management programs on functional status of patients with rheumatoid arthritis
Authors: Badamgarav Enkhe , Croft Joseph D. , Hohlbauch Andriana , Louie James S. , O'Dell James , Ofman Joshua J. , Suarez‐Almazor Maria E. , Weaver Arthur , White Patience , Katz Paul ,   on behalf of The Evidence‐Based Medicine Working Groups in Rheumatology
Published: June 2003

Objective

To perform a systematic review of the published literature on disease management of rheumatoid arthritis (RA) and to use metaanalysis to estimate the magnitude of benefit these programs have on functional status in patients with RA.

Methods

Computerized databases for English articles from 1966 to September 2001 were searched. Two reviewers evaluated 1,029 published titles, identified 11 studies meeting explicit inclusion criteria, and extracted data about study characteristics, interventions used, and outcomes measured. Pooled effect sizes for functional status were calculated using a random‐effects model.

Results

Four out of 8 disease management programs showed significant improvements in functional status; however, the pooled effect size (ES) was small and statistically non‐significant (ES 0.27; 95% confidence interval [95% CI] −0.01, 0.54). Studies with longer intervention durations (>5 weeks) had significantly improved patient functional status (ES 0.49; 95% CI 0.12, 0.86), compared with studies with shorter intervention durations (≤5 weeks, ES 0.13; 95% CI −0.25, 0.52).

Conclusions

There were limited data to support or refute the effectiveness of disease management programs in improving functional status in patients with RA. Additional studies are needed to confirm if a more intensive intervention may be of benefit to patients with RA, as suggested by our study.
Operant behavioral treatment of fibromyalgia: A controlled study
Authors: Thieme Kati , Gromnica‐Ihle Erika , Flor Herta
Published: June 2003

Objective

To evaluate the efficacy of operant pain treatment for fibromyalgia syndrome (FMS) in an inpatient setting.

Methods

Sixty‐one patients who fulfilled the American College of Rheumatology criteria for FMS were randomly assigned to the operant pain treatment group (OTG; n = 40) or a standardized medical program with an emphasis on physical therapy (PTG; n = 21). Pain assessments were performed before, immediately after, 6 months after, and 15 months after treatment.

Results

The OTG patients reported a significant and stable reduction in pain intensity, interference, solicitous behavior of the spouse, medication, pain behaviors, number of doctor visits, and days at a hospital as well as an increase in sleeping time. Sixty‐five percent of the OTG compared with none of the patients in the PTG showed clinically significant improvement.

Conclusion

These results suggest that operant pain treatment provided in an inpatient setting is an effective treatment for FMS, whereas a purely somatically oriented program may lead to a deterioration of the pain problem.
Etanercept added to background methotrexate therapy in patients with rheumatoid arthritis: Continued observations
Authors: Kremer Joel M. , Weinblatt Michael E. , Bankhurst Arthur D. , Bulpitt Ken J. , Fleischmann Roy M. , Jackson Christopher G. , Atkins Kelly M. , Feng Anyang , Burge Daniel J.
Published: June 2003

Objective

To observe the long‐term safety and efficacy of combination therapy with etanercept and methotrexate in patients with rheumatoid arthritis (RA), and to determine whether the addition of etanercept allowed reductions in methotrexate or corticosteroid dosages while maintaining a clinical response.

Methods

Patients with RA who received methotrexate plus etanercept in a previous randomized, placebo‐controlled trial were offered the opportunity to enroll in an open‐label extension study for further evaluation of treatment with etanercept and methotrexate.

Results

Seventy‐nine of the 89 patients in the original blinded study enrolled in the extension study, and 65 of these patients continue in the study. Patients have received etanercept therapy for up to 47 months (median 44 months). The types and rate of adverse events noted during the extension trial were similar to those observed in the controlled trial. At the 3‐year assessment, 77% of the 57 patients available for evaluation met American College of Rheumatology 20% (ACR20) criteria for improvement in RA, 47% met the ACR50 criteria, and 23% met the ACR70 criteria. Of the 36 patients assessed at 3 years in the extension study, 30 (83%) were able to decrease their dosages of corticosteroids, and 20 (56%) were able to discontinue corticosteroid therapy. At 3 years, the dosage of methotrexate was decreased in 41 of 66 patients (62%), and methotrexate therapy was discontinued in 19 patients (29%).

Conclusion

In this observational continuation study, the addition of etanercept to background methotrexate provided sustained clinical benefit over a median period of 44 months. With etanercept therapy, there were trends toward dosage reduction or discontinuation of methotrexate and corticosteroids, without apparent worsening of ACR response rates. Compared with the controlled trial, no increases in the rate of adverse events were observed.
Confidence Intervals for Relative Risks in Disease Mapping
Authors: Ugarte M.D. , Militino A.F. , Ibáñez B.
Published: June 2003

Several analysis of the geographic variation of mortality rates in space have been proposed in the literature. Poisson models allowing the incorporation of random effects to model extra‐variability are widely used. The typical modelling approach uses normal random effects to accommodate local spatial autocorrelation. When spatial autocorrelation is absent but overdispersion persists, a discrete mixture model is an alternative approach. However, a technique for identifying regions which have significant high or low risk in any given area has not been developed yet when using the discrete mixture model. Taking into account the importance that this information provides to the epidemiologists to formulate hypothesis related to the potential risk factors affecting the population, different procedures for obtaining confidence intervals for relative risks are derived in this paper. These methods are the standard information‐based method and other four, all based on bootstrap techniques, namely the asymptotic‐bootstrap, the percentile‐bootstrap, the BC‐bootstrap and the modified information‐based method. All of them are compared empirically by their application to mortality data due to cardiovascular diseases in women from Navarra, Spain, during the period 1988–1994. In the small area example considered here, we find that the information‐based method is sensible at estimating standard errors of the component means in the discrete mixture model but it is not appropriate for providing standard errors of the estimated relative risks and hence, for constructing confidence intervals for the relative risk associated to each region. Therefore, the bootstrap‐based methods are recommended for this matter. More specifically, the BC method seems to provide better coverage probabilities in the case studied, according to a small scale simulation study that has been carried out using a scenario as encountered in the analysis of the real data.
Unconditional Confidence Interval for the Difference between Two Proportions
Authors: Martín Andrés A. , Herranz Tejedor I.
Published: June 2003

In applied statistics it is customary to have to obtain a one‐ or two‐tail confidence interval for the difference d = p2 – p1 between two independent binomial proportions. Traditionally, one is looking for a classic and non‐symmetric interval (with respect to zero) of the type d ∈ [δL;δU], d ≤ δ0 or d ≥ δ0. However, in clinical trials, equivalence studies, vaccination efficacy studies, etc., and even after performing the classic homogeneity test, intervals of the type |d| ≤ Δ0 or |d| ≥ Δ0, where Δ0 > 0, may be necessary. In all these cases it is advisable to obtain the interval by inverting the appropriate test. The advantage of this procedure is that the conclusions obtained using the test are compatible with those obtained using the interval. The article shows how this is done using the new exact and asymptotic unconditional tests published. The programs for performing these tests may be obtained at URL http://www.ugr.es/~bioest/software.htm.
Statistical Methods for Ordered Categorical Data Based on a Constrained Odds Model
Authors: Dark Roberta , Bolland Kim , Whitehead John
Published: June 2003

The proportional odds model provides a powerful tool for analysing ordered categorical data and setting sample size, although for many clinical trials its validity is questionable. The purpose of this paper is to present a new class ofconstrained odds modelswhich includes the proportional odds model. The efficient score and Fisher's information are derived from the profile likelihood for the constrained odds model. These results are new even for the special case of proportional odds where the resulting statistics define the Mann‐Whitney test. A strategy is described involving selecting one of these models in advance, requiring assumptions as strong as those underlying proportional odds, but allowing a choice of such models. The accuracy of the new procedure and its power are evaluated.
Network algorithm for the Exact Test of Hardy‐Weinberg Proportion for Multiple Alleles
Authors: Aoki S.
Published: June 2003

We propose a new technique for the exact test of Hardy‐Weinberg proportion that considerably extends the bounds of computational feasibility. Our algorithm is constructed analogously to the network algorithm for Freeman‐Halton exact test in two‐way contingency tables. In this algorithm, the smallest and the largest values for the statistic are important and some interesting new theorems are proved for computing these values. Numerical examples are given to illustrate the practicality of our algorithm.
Profiling of dynamic changes in hypermetabolic livers
Authors: Lee Kyongbum , Berthiaume François , Stephanopoulos Gregory N. , Yarmush Martin L.
Published: June 2003

The liver plays an important role in the overall negative nitrogen balance leading to muscle wasting commonly observed in patients following many conditions, including severe injury, cancer, and diabetes. In order to study changes in liver metabolism during the establishment of such catabolic states, we used a rat skin burn injury model that induces hypermetabolism and muscle wasting. At various times during the first week following the injury, livers were isolated and perfused in a recirculating system under well‐defined conditions. We applied a steady‐state metabolic flux analysis model of liver metabolism and then used k‐means clustering to objectively group together reaction flux time profiles. We identified six distinct groups of reactions that were differentially responsive: (1) pentose phosphate pathway (PPP); (2) amino acid oxidation reactions leading to the formation of tricarboxylic acid (TCA) cycle intermediates; (3) gluconeogenesis; (4) TCA‐cycle and mitochondrial oxidation; (5) lipolysis, β‐oxidation, and ketone body formation; and (6) urea‐cycle. Burn injury sequentially upregulated the urea‐cycle, the PPP, and the TCA‐cycle, in order, while β‐oxidation and gluconeogenesis remained unchanged. The upregulation of the PPP was transient, whereas the rise in urea‐ and TCA‐cycle fluxes was sustained. An ATP balance predicted an increased production of ATP and energy expenditure starting on day 3 post‐burn, which correlated with the induction of the oxidative phosphorylation uncoupler uncoupling protein‐2. We conclude that metabolic profiling using flux analysis and clustering analysis is a useful methodology to characterize the differential activation of metabolic pathways in perfused organs and to identify specific key pathways that are sensitive to a stimulus or insult without making a priori assumptions. Biotechnol Bioeng 83: 400–415, 2003. © 2003 Wiley Periodicals, Inc.
Critical evaluation of sampling techniques for residual glucose determination in carbon‐limited chemostat culture of Saccharomyces cerevisiae
Authors: Mashego M. R. , van Gulik W. M. , Vinke J. L. , Heijnen J. J.
Published: June 2003

In this paper, three sampling techniques for rapid quenching of cellular metabolism and subsequent separation of cells from fermentation broth are compared: (i) quick freezing of fermentation broth directly in liquid nitrogen; (ii) quenching metabolism by exposing the fermentation broth to stainless steel beads (4‐mm diameter) in a filter syringe precooled to −18°C; and (iii) withdrawal of the filtrate through a 0.45‐μm filter attached to a syringe and a needle inserted directly into the fermentor. It was concluded that use of liquid nitrogen as a quenching method to rapidly arrest cellular metabolism, for quantitative analysis of extracellular glucose, is not a very reliable method and that the filter syringe steel beads work very well. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 83: 395–399, 2003.
Interfacial versus homogeneous enzymatic cleavage of mandelonitrile by hydroxynitrile lyase in a biphasic system
Authors: Cascão‐Pereira Luis G. , Hickel Andrea , Radke Clayton J. , Blanch Harvey W.
Published: June 2003

The question of an interfacial versus ahomogeneous reaction is carefully addressed for the enzymatic biphasic cleavage of mandelonitrile to benzaldehyde by Prunus amygdalus hydroxynitrile lyase (pa‐Hnl) (Hickel et al. [1999] Biotechnol Bioeng 36:425–436). Experimental evidence, including 1) the reaction ceases when the interface is populated by previously adsorbed denatured pa‐Hnl, 2) the reaction continues even after washout of the bulk enzyme from the aqueous phase, 3) highly nonpolar organic solvents initially promote fast reaction kinetics that relatively quickly decay to zero product production, and 4) the reaction rate is nonlinear in the bulk enzyme concentration, provide robust grounds for an interfacial reaction. We also model enzymatic mandelonitrile cleavage assuming a homogeneous aqueous‐phase reaction. The homogeneous reaction scheme does not simultaneously account for the experimental observations of a linear dependence of the reaction rate on organic/water interfacial area, no dependence on the aqueous‐phase volume, and a nonlinear dependence on pa‐Hnl aqueous concentration. Further, simple calculations demonstrate that the homogeneous reaction rate is at least three orders of magnitude slower than those observed by Hickel et al. (1999). We again conclude that enzyme adsorbed at the organic solvent/water interface primarily catalyzes the biphasic mandelonitrile cleavage reaction. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 83: 498–501, 2003.
Role of water‐soluble polysaccharides in bacterial cellulose production
Authors: Ishida Takehiko , Mitarai Makoto , Sugano Yasushi , Shoda Makoto
Published: June 2003

Acetobacter xylinum BPR2001 produces water‐insoluble bacterial cellulose (BC) and a water‐soluble polysaccharide called acetan in corn steep liquor‐fructose medium. Acetobacter xylinum EP1, which is incapable of acetan production was derived by disrupting the aceA gene of BPR2001. The BC production by EP1 (2.88 g/L) was lower than that by BPR2001 (4.6 g/L) in baffled‐flask culture. When purified acetan or agar was added to the medium from the start of cultivation, the BC production by EP1 was enhanced and the final BC yield of EP1 was almost the same as that of BPR2001. A similar improvement of BC production by EP1 by the addition of agar was also confirmed by cultivation in a 50‐L airlift reactor. From these results, the role of acetan in BC production is associated with the increase in the viscosity of the culture medium which may hinder coagulation of BC and cells in the culture, thereby accelerating the growth of BPR2001and BC production by BPR2001. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 83: 474–478, 2003.
Analyses of microbial desulfurization reaction of alkylated dibenzothiophenes dissolved in oil phase
Authors: Okada Hideki , Nomura Nobuhiko , Nakahara Tadaatsu , Saitoh Koichi , Uchiyama Hiroo , Maruhashi Kenji
Published: June 2003

The kinetics of the oil/water two‐phase reaction system was analyzed, and the reaction was carried out with the desulfurization of alkylated dibenzothiophenes (Cx‐DBTs) using the desulfurizing microorganism Mycobacterium sp. G3. In the water‐phase reaction system, the desulfurization activities were constant with respect to species of Cx‐DBTs as substrates. However, the desulfurization activities in the oil/water two‐phase reaction system against DBT, 4,6‐dimethyl DBT, 4,6‐diethyl DBT, 4,6‐dipropyl DBT, and 4,6‐dibutyl DBT were 49.0, 45.9, 11.5, 1.35, and 0.00 μmol g DCW−1 h−1, respectively. The kinetic parameters for the degradation of DBT, 4,6‐dimethyl DBT, and 4,6‐diethyl DBT were also obtained (Vmax values 90.0, 68.7, and 22.7 μmol g DCW−1 h−1 and Km values 0.21, 0.70, and 3.03 mM, respectively). The reason for the decrease in activity against Cx‐DBTs of high molecular weight was a decrease in the Vmax value and an increase in the Km value, the latter being a particularly serious problem. Furthermore, the hydrophobicity of the substrate was evaluated as the capacity factor measured by high‐performance liquid chromatography (HPLC). The correlation between substrate hydrophobicity and desulfurization activity indicated that the desulfurization reaction in the oil/water two‐phase reaction system is greatly influenced by the hydrophobicity of the substrates. In addition, the influence of the solvent on desulfurization activity was examined, and it was found that not only the hydrophobicity of substrates, but also that of solvents, affected the desulfurization reaction. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 83: 489–497, 2003.
Ferrocenyl‐Functionalised Terpyridines and Their Transition‐Metal Complexes: Syntheses, Structures and Spectroscopic and Electrochemical Properties
Authors: Siemeling Ulrich , Vor der Brüggen Jens , Vorfeld Udo , Neumann Beate , Stammler Anja , Stammler Hans‐Georg , Brockhinke Andreas , Plessow Regina , Zanello Piero , Laschi Franco , Fabrizi de Biani Fabrizia , Fontani Marco , Steenken Steen , Stapper Marion , Gurzadyan Gagik
Published: June 2003

Terpyridine ligands of the type Fc′‐X‐tpy′ (Fc′=ferrocenyl or octamethylferrocenyl, X=rigid spacer, tpy′=4′‐substituted 2,2′:6′,2″‐terpyridine) were prepared, crystallographically characterised and used for the synthesis of di‐ and trinuclear bis(terpyridine) complexes of RuII, FeII and ZnII. Donor–sensitiser dyads and triads based on RuII were thoroughly investigated by (spectro)electrochemistry, UV/Vis, transient absorption and luminescence spectroscopy, and an energy level scheme was derived on the basis of the data collected. Intramolecular quenching of the photoexcited RuII complexes by the redox‐active Fc′ groups can occur reductively and by energy transfer. Both the redox potential of the donor Fc′ and the nature of the spacer X have a decisive influence on excited‐state lifetimes and emission properties of the complexes. Some of the compounds show room‐temperature luminescence, which is unprecedented for ferrocenyl‐functionalised compounds of this kind.
Photoinduced Intramolecular Electron Transfer and Triplet Energy Transfer in a Steroid‐Linked Norbornadiene–Carbazole Dyad
Authors: Zhang Li‐Ping , Chen Bin , Wu Li‐Zhu , Tung Chen‐Ho , Cao Hong , Tanimoto Yoshifumi
Published: June 2003

Bichromophoric compound 3β‐((2‐(methoxycarbonyl)bicyclo[2.2.1]hepta‐2,5‐diene‐3‐yl)carboxy)androst‐5‐en‐17β‐yl‐[2‐(N‐carbazolyl)acetate] (NBD‐S‐CZ) was synthesized and its photochemistry was examined by fluorescence quenching, flash photolysis, and chemically induced dynamic nuclear polarization (CIDNP) methods. Fluorescence quenching measurements show that intramolecular electron transfer from the singlet excited state of the carbazole to the norbornadiene group in NBD‐S‐CZ occurs with an efficiency (ΦSET) of about 14 % and rate constant (kSET) of about 1.6×107 s−1. Phosphorescence and flash photolysis studies reveal that intramolecular triplet energy transfer and electron transfer from the triplet carbazole to the norbornadiene group proceed with an efficiency (ΦTET + ΦTT) of about 52 % and rate constant (kTET + kTT) of about 3.3×105 s−1. Upon selective excitation of the carbazole chromophore, nuclear polarization is detected for protons of the norbornadiene group (emission) and its quadricyclane isomer (enhanced absorption); this suggests that the isomerization of the norbornadiene group to the quadricyclane proceeds by a radical‐ion pair recombination mechanism in addition to intramolecular triplet sensitization. The long‐distance intramolecular triplet energy transfer and electron transfers starting both from the singlet and triplet excited states are proposed to proceed by a through‐bond mechanism.
Formation of MoS2 Inorganic Fullerenes (IFs) by the Reaction of MoO3 Nanobelts and S
Authors: Li Xiao Lin , Li Ya Dong
Published: June 2003

The reaction of MoO3 and S at temperatures higher than 300 °C in an argon atmosphere provides a convenient and effective method for the synthesis of MoS2 nanocrystalline substances. MoS2 nanotubes and fullerene‐like nanoparticles have been obtained by the reaction at 850 °C under well‐controlled conditions. The influences of reaction temperature and duration were carefully investigated in this paper. All of the nanostructures were characterized by Xray powder diffraction (XRD), transmission electron microscopy (TEM), and high‐resolution transmission electron microscopy (HRTEM). A stepwise reaction model and rolling mechanism were proposed based on the experimental results.
Substrate‐Controlled Highly Diastereoselective Synthesis of Primary and Secondary Diorganozinc Reagents by a Hydroboration/Boron–Zinc Exchange Sequence
Authors: Hupe Eike , Calaza M. Isabel , Knochel Paul
Published: June 2003

The scope of substrate‐controlled diastereoselective hydroborations can be considerably enhanced by a boron–zinc exchange reaction, providing organozinc derivatives that react with a broad range of electrophiles. Even normally unreactive boronic esters, obtained by Rh‐catalyzed hydroboration with catecholborane, react readily with iPr2Zn providing the corresponding zinc reagents in high diastereoselectivity.
Hybrid Organic–Inorganic 1D and 2D Frameworks with ε‐Keggin Polyoxomolybdates as Building Blocks
Authors: Dolbecq Anne , Mialane Pierre , Lisnard Laurent , Marrot Jérôme , Sécheresse Francis
Published: June 2003

Organic–inorganic hybrid materials based on polyoxometalate building blocks with capping La3+ ions and bidentate oxygenated ligands have been obtained by reaction at room temperature of the [ε‐PMo12O36(OH)4{La(H2O)4}]5+ polyoxocation with glutarate (C5H6O22−) and squarate (C4O42−) organic ligands. [ε‐PMo12O37(OH)3{La(H2O)4(C5H6O4)0.5}4]⋅21 H2O (1) and [ε‐PMo12O39(OH){La(H2O)6}2{La(H2O)5(C4O4)0.5}2]⋅17 H2O (2) form unprecedented 1D chains built from alternating polyoxocations and organic ligands connected through LaO links. The structures of these materials are compared to the 2D hybrid organic–inorganic framework [NC4H12]2[Mo22O52(OH)18{La(H2O)4}2{La(CH3CO2)2}4]⋅8 H2O (3) isolated from the hydrothermal reaction of elemental precursors (MoO42−, Mo, La3+) in acetate buffer. Compound 3 is built from previously undescribed polyoxometalate units with twenty‐two MoV centers capped by six La3+ ions, four of which are bridged by acetate ligands.
Highly Diastereoselective [3+2] Cycloadditions between Nonracemic p‐Tolylsulfinimines and Iminoesters: An Efficient Entry to Enantiopure Imidazolidines and Vicinal Diaminoalcohols
Authors: Viso Alma , Fernández de la Pradilla Roberto , García Ana , Guerrero‐Strachan Carlos , Alonso Marta , Tortosa Mariola , Flores Aida , Martínez‐Ripoll Martín , Fonseca Isabel , André Isabelle , Rodríguez Ana
Published: June 2003

A new procedure for the asymmetric synthesis of imidazolidines and vicinal diamines is reported. The 1,3‐dipolar cycloaddition between nonracemic p‐tolylsulfinimines and azomethine ylides generated in situ from α‐iminoesters and LDA produces N‐sulfinylimidazolidines with a high degree of stereocontrol. In contrast, the presence of Lewis acids promotes formation of the cycloadducts through a highly diastereoselective process with opposite stereochemistry. Subsequent transformations of the imidazolidines including oxidative, reductive, and hydrolytic processes that provide easy access to vicinal diaminoalcohols have been explored. Among these, reductive cleavage of the aminal with LiAlH4 is an extremely efficient and general reaction for the synthesis of enantiopure N‐sulfinyl‐N′‐benzyldiaminoalcohols.
Synthesis of Enantiomerically Enriched Propargylamines by Copper‐Catalyzed Addition of Alkynes to Enamines
Authors: Koradin Christopher , Gommermann Nina , Polborn Kurt , Knochel Paul
Published: June 2003

The first copper(I) bromide/Quinap‐catalyzed synthesis of enantiomerically enriched propargylamines by addition of alkynes to enamines is reported. Various functionalized terminal alkynes add smoothly to Nprotected enamines to afford the corresponding amines in good to high yields and moderate to good enantiomeric excesses. The influence of the metal salt, the ligand, and the protecting group on the conversion, the reaction rate, and the stereoselectivity of the reaction are investigated. The scope of the reaction and further transformations of the resulting propargylamines (deprotection, Pauson–Khand reaction) are also described.
Laser Spectroscopic Studies of Interactions of UVI with Bacterial Phosphate Species
Authors: Knopp Roger , Panak Petra J. , Wray Lewis A. , Renninger Neil S. , Keasling Jay D. , Nitsche Heino
Published: June 2003

We have investigated the interactions of UVI with two bacterial phosphate‐containing species: Gram‐positive Bacillus sphaericus and Gram‐negative Psedomonas aeruginosa. The Gram‐positive B. sphaericus was investigated by using Raman spectroscopy and time‐resolved laser‐induced fluorescence spectroscopy (TRLFS). We found that living cells, spores, and intact heat‐killed cells complexed UVI (pH 4.5) through phosphate groups bound to their surfaces, while decomposed cells released H2PO4− and precipitated UVI as UO2(H2PO4)2. TRLFS of UVI showed that Gram‐negative P. aeruginosa—genetically engineered to accumulate polyphosphate, subsequently degrade it, and secrete phosphate—precipitated UVI quantitatively at pH 4.5. The same bacterial strain, not induced to secrete phosphate, sorbed only a small amount of UVI.
The Carbon Skeleton of the Belt Region of Fullerene C84 (D2)
Authors: Neudorff Wolf Dietrich , Lentz Dieter , Anibarro Maribel , Schlüter A. Dieter
Published: June 2003

The synthesis and structural characterization of the double‐stranded carbon skeleton in the belt region of a C84 fullerene has been achieved. The synthetic methodology used is based on cyclic dimerization of diastereomeric AB‐type monomers 18 by a non‐diastereospecific Diels–Alder reaction with isobenzofuran and acenaphthylene groups as reactive termini. Four diasteromeric monomer precursors 17 were prepared for the first time by the use of dihydropyracylene (12) in a multistep synthesis. The synthesis of dihydropyracylene itself has been optimized to the degree that it is now available on the 10 g scale. The belt‐shaped macrocycle 19, obtained from dimerization of the monomers 17, could be partly aromatized by an acid‐catalyzed dehydration reaction to give 23, which differs from the fully unsaturated belt by two “water” molecules. Semiempirical AM1 calculations of the electronic and thermodynamic properties of cyclic fluoranthenes revealed strain energy as the essential reason for the incomplete aromatization of 19. The structures of the macrocycles 19 and 23, one of the monomer precursors, and two diastereomeric epoxybenzo[k]fluoranthenes were elucidated by single‐crystal Xray crystallography.
MTO and OsO4: An Efficient Catalytic Couple for Mild H2O2‐Based Asymmetric Dihydroxylation of Olefins
Authors: Jonsson Sandra Y. , Adolfsson Hans , Bäckvall Jan‐E.
Published: June 2003

A novel and robust system for osmium‐catalyzed asymmetric dihydroxylation of olefins by aqueous H2O2 with methyltrioxorhenium (MTO) as electron transfer mediator (ETM) has been developed. The MTO is catalyzing the H2O2 oxidation of the chiral ligand to its mono‐N‐oxide, which in turn reoxidizes OsVI to OsVIII. Thus the (DHQD)2PHAL plays a dual role serving as the chiral inductor as well as the tertiary amine generating the N‐oxide required for the recycling of osmium. The present catalytic system gives vicinal diols in good isolated yields and high enantiomeric excess (up to 99 % ee).
Controlling the Conformation and Interplay of p‐Sulfonatocalix[6]arene as Lanthanide Crown Ether Complexes
Authors: Dalgarno Scott J. , Hardie Michaele J. , Makha Mohamed , Raston Colin L.
Published: June 2003

Control over the conformational flexibility of p‐sulfonatocalix[6]arene in the solid state is possible in the presence of varied stoichiometric amounts of [18]crown‐6 and selected lanthanide(III) chlorides. Complexes 1 and 2 have the calixarene in the elusive “up–up” double cone conformation, whilst complex 3 has the calixarene in the centrosymmetric “up–down” double partial cone conformation, whereby it acts as a divergent receptor. Complex 1 has a double “molecular capsule” arrangement which is composed of two p‐sulfonatocalix[6]arenes shrouding two [18]crown‐6 molecules, also with both coordinated and homoleptic aquated lanthanide ions around the hydrophilic sulfonate rims of the calixarenes. Complex 2 has a “ferris wheel” arrangement with one lanthanide metal centre coordinated to a sulfonate group and another coordinated to the crown ether whilst tethered to a sulfonate group of the calixarene. Complex 3 forms from a solution with large excess of [18]crown‐6, and possesses a crown ether molecule in each of the partial cones and has homoleptic aquated lanthanide ions involved in a complicated hydrogen‐bonding regime within the extended structure.
Polynitrogen Chemistry: Preparation and Characterization of (N5)2SnF6, N5SnF5, and N5B(CF3)4
Authors: Wilson William W. , Vij Ashwani , Vij Vandana , Bernhardt Eduard , Christe Karl O.
Published: June 2003

Metathetical processes were used to convert N5SbF6 into N5[B(CF3)4] and (N5)2SnF6. The latter salt is especially noteworthy because it contains two N5+ ions per anion, thus demonstrating that salts with touching polynitrogen cations can be prepared. This constitutes an important milestone towards our ultimate goal of synthesizing a stable, ionic nitrogen allotrope. The stepwise decomposition of (N5)2SnF6 yielded N5SnF5. Multinuclear NMR spectra show that in HF the SnF5− ion exists as a mixture of Sn2F102− and Sn4F204− ions. Attempts to isolate FN5 from the thermolysis of (N5)2SnF6 were unsuccessful, yielding only the expected decomposition products, FN3, N2, trans‐N2F2, NF3, and N2.
Cover Picture: The Synthesis of Carboracycles Derived from B,B′‐Bis(aryl) Derivatives of Icosahedral ortho‐Carborane (Chem. Eur. J. 12/2003)
Authors: Bayer Michael J. , Herzog Axel , Diaz Martin , Harakas George A. , Lee Hans , Knobler Carolyn B. , Hawthorne M. Frederick
Published: June 2003

The cover picture shows a space‐filling model of a macrocycle consisting of four bis‐aryl‐substituted icosahedral ortho‐carborane modules that are tethered with propylene linkers (carbon: gray, boron: green, hydrogen: white). All eight para‐functionalized aryl groups are attached to a propylene chain carrying a terminal sulfonate group (sulfur: yellow, oxygen: blue). This amphiphilic octasulfonate anion exemplifies the first water‐soluble carboracycle. The hydrophobic cavity in the cycle is clearly viable and adjustable by inter‐cage linker modification. The development of new supramolecular chemistry and its use in molecular recognition employing solvent systems that range from organic to aqueous represent future applications of these novel carboracycle derivatives. For more details concerning the synthesis and characterization of these multifunctionalized carborane‐based macrocycles see the article by M. F. Hawthorne et al. on p. 2732 ff.
Vom einfachen Komplex zum komplexen Gitter: Metallo‐supramolekulare Chemie
Authors: Schmatloch Stefan , Schubert Ulrich S.
Published: June 2003

Koordinationsverbindungen, die bereits im vorletzten Jahrhundert durch die klassische Komplexchemie und Koordinationslehre beschrieben wurden und seit den späten 50iger Jahren intensiv auf dem Gebiet der homogenen und heterogenen Katalyse Einsatz finden, stehen erneut im Mittelpunkt eines neuen Forschungsbereichs: der metallo‐supramolekularen Chemie. Komplizierte, supramolekulare Liganden, als Weiterentwicklung einfacher einzähniger Liganden und Chelatliganden, führen auf der Basis von Selbstorganisations‐ und Selbsterkennungsprozessen zusammen mit koordinierenden Metallionen zu genau definierten supramolekularen Architekturen. Die Natur nutzt diese als wesentliche Funktionsträger in biologischen Systemen, z. B. den Hämoglobin‐Eisen‐Komplex. Diesem Vorbild folgend versucht die supramolekulare Chemie, hochkomplexe, jedoch genau definierte Geometrien, wie Helikate, Fäden, Leitern, Rechen oder Gitter präparativ herzustellen und somit neuartige Materialien mit speziellen Eigenschaften zu entwickeln. Der Metallkomplex als zentrale Einheit der neuen Verbindungsklasse kann zu „funktionalen supramolekularen Systemen”︁ führen. Diese könnten Anwendungen auf den Gebieten der Polyelektrolyte, der Elektrochemie (elektrisch leitende Polymere und Redoxkatalysatoren) und der Photochemie (organische Solarzellen) ermöglichen.
Die Herstellung von Reinstsiliciumscheiben: Mehr Chemie als man glaubt
Authors: Wenski Guido , Hohl Georg , Storck Peter , Crößmann Ivo
Published: June 2003

Einkristalline Halbleiterscheiben aus Silicium stellen die Grundlage für mikroelektronische Bauelemente dar. Die Umwandlung des Ausgangsmaterials Quarz in eine epitaktisch beschichtete 300‐mm‐Scheibe umfasst eine Vielzahl von Prozessschritten, die teilweise deutlich von chemischen Verfahren geprägt sind. Der vorliegende Aufsatz führt in die Herstellung von Halbleitersilicium sowie die Verfahren Ätzen, Polieren, Reinigen und Epitaxie ein. Was diesen Technologiezweig auszeichnet, sind die extremen Anforderungen an Oberfächenperfektion und Reinheit, die sich in Atomlagen (Oberflächenrauheit der Scheiben) und parts per trillion (Kontamination der Chemikalien) ausdrücken lassen.
Characterization of paraffin oils and petrolatum using LDI‐TOF MS and principle component analysis
Authors: Prunsa Julia K. , Rapp Claudius , Hintze Ulrich , Wittern Klaus‐Peter , König Wilfried A.
Published: June 2003

Laser desorption/ionization time‐of‐flight mass spectrometry (LDI‐TOF MS) followed by evaluation of the mass spectra with principal component analysis (PCA) was used for the in‐depth characterization of paraffin oils (mineral oils) and petrolatum (paraffin jelly) samples. These raw materials are liquid and semisolid mixtures of hydrocarbons obtained from petroleum. Mass spectrometric analysis was done using a solvent‐free sample preparation with silver trifluoroacetate. The analysis was carried out on a commercially available matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometer.

Mass spectra were evaluated using parameters calculated from the areas of different alkane and cycloalkane species and by PCA. The ratios between specific peak areas were chosen as PCA‐input data instead of the less reproducible absolute peak areas.

The principal components enable comparison of a large number of samples and can also be used for visualization of data. In this work, it is clearly demonstrated that combining LDI‐TOF MS and PCA provides a fast and efficient tool for the characterization of paraffin oils and petrolatum. Petrolatum and four different kinds of paraffin oil were analyzed and the results compared with other analytical methods.
Synthesis and Properties of Oligodeoxynucleotides Possessing N‐Phosphoryl Groups
Authors: Moriguchi Tomohisa , Wada Takeshi , Sekine Mitsuo
Published: June 2003

This paper deals with the synthesis and properties of oligodeoxynucleotides of a Dickerson−Drew sequence, d(CGCGAATTCGCG), in which one of the four cytosine bases has been replaced with an N‐phosphorylated or N‐diethylphosphorylated cytosine base in order to study the effect of the N‐phosphoryl or N‐diethoxyphosphoryl group on their structural property and hybridization affinity. The CD spectra of these self‐complementary duplexes showed the typical B DNA‐type shape with very minor changes. In contrast, it was found from Tm experiments that N‐phosphoryl groups destabilized the DNA duplexes significantly through steric hindrance and electronic repulsion. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Study of the Reactions between Vinylmagnesium Bromide and Imines Derived from (R)‐Glyceraldehyde − The Key Step in the Stereodivergent Synthesis of Conveniently Protected, Enantiopure syn‐ and anti‐2‐Amino‐1,3,4‐butanetriol Derivatives
Authors: Badorrey Ramón , Cativiela Carlos , Díaz‐de‐Villegas Maria D. , Díez Roberto , Gálvez José A.
Published: June 2003

A total stereodivergent method for the synthesis of enantiopure syn‐ and anti‐2‐amino‐1,3,4‐butanetriol (ABT) derivatives from inexpensive and readily available D‐mannitol has been developed. Key steps include: (a) the diastereoselective addition of vinylmagnesium bromide to conveniently protected N‐benzylimines derived from (R)‐glyceraldehyde, and (b) the oxidative degradation of the C−C double bond of the resultant syn‐ and anti‐vinylaminodiol derivatives. The addition of vinylmagnesium bromide in diethyl ether to the N‐benzylimine derived from (R)‐2,3‐O‐isopropylideneglyceraldehyde affords the anti‐vinylaminodiol derivative, while the reaction with the N‐benzylimine derived from (R)‐2,3‐di‐O‐benzylglyceraldehyde affords the syn‐vinylaminodiol derivative, both with excellent diastereoselectivities (de > 98/2). Moreover, a reversal of the stereochemical course of the reaction is produced when (R)‐2,3‐O‐isopropylideneglyceraldehyde N‐benzylimine is precomplexed with ZnI2, in this case yielding the syn addition adduct as the major compound. Different reaction conditions (reagent molar ratio, reaction temperature) have been tested in order to determine their influences on the observed yields and diastereoselectivities. From the results of this study and a subsequent crossover experiment, some interesting mechanistic considerations can be inferred. Enantiopure anti‐ and syn‐vinylaminodiol adducts have been successfully converted into conveniently protected anti‐ and syn‐2‐amino‐1,3,4‐butanetriol (ABT) derivatives, key building blocks in the asymmetric synthesis of biologically active compounds. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
New, Regioselective, One‐Pot Synthesis of (all‐E)‐Retinoic Acid and Analogues from Enaminodiester Synthons
Authors: Cartier Dominique , Valla Alain , Guillou Régis Le , Labia Roger , Potier Pierre
Published: June 2003

A one‐pot synthesis of (all‐E)‐retinoic acid and related compounds from new enamino diester synthons is described. The enamino diesters was produced nearly quantitatively from methyl propylidene‐ and isopropylidenemalonate and DMF−DMA. This easy process allowed retinoic acid to be produced in 1 d and appeared advantageous to current industrial syntheses. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Synthesis and Structural Analysis of Cyclic Oligomers Consisting of Furanoid and Pyranoid ϵ‐Sugar Amino Acids
Authors: Well Renate M. van , Marinelli Luciana , Erkelens Kees , Marel Gijsbert A. van der , Lavecchia Antonio , Overkleeft Herman S. , Boom Jacques H. van , Kessler Horst , Overhand Mark
Published: June 2003

Cyclic oligomers composed of amide‐linked furanoid (i.e., 1, 3) and pyranoid (i.e., 2, 4) ϵ‐sugar amino acids (SAAs) were prepared by a cyclization/cleavage approach with use of the oxime resin. These cyclic homooligomers were constructed by use of the known N‐Boc protected furanoid ϵ‐SAA 11 and the novel pyranoid hydroxymethylene homologue 22. Conformational analysis of cyclic trimer 1 by an unrestrained simulated annealing technique showed that the furanoid rings of the residues I flip between a twist (north, P = 0°) and an envelope (south, P = 167°) conformation. Furthermore, the side chains connecting the carbonyl functionality (i.e. C2) proved to be rigid, while the other side chains (C7) are conformationally flexible. Similar conformational behaviour is observed for the side chains of the pyranoid ϵ‐SAA II residues in trimer 2, but the pyranoid ring chair conformation remains stable during the calculation. These conformational details may have important implications in the future design of SAA‐based artificial receptors or peptidomimetics. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Construction of Spiro[pyrrolidine‐3,3′‐oxindoles] − Recent Applications to the Synthesis of Oxindole Alkaloids
Authors: Marti Christiane , Carreira Erick M.
Published: June 2003

The spiro[pyrrolidine‐3,3′‐oxindole] ring system is found at the core of a number of alkaloids, which possess significant biological activity and are interesting, challenging targets for chemical synthesis. In the present review, we report on the different strategies for the synthesis of the spiro[pyrrolidine‐3,3′‐oxindole] ring system in the context of recent synthesis of coerulescine, horsfiline, elacomine, salacin, pteropodine, alstonisine, spirotryprostatin A and B, and strychnofoline. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
The Development of a Practical Total Synthesis of Discodermolide, a Promising Microtubule‐Stabilizing Anticancer Agent
Authors: Paterson Ian , Florence Gordon J.
Published: June 2003

Marine organisms provide an important source of natural product diversity with an associated range of significant biological activities. Discodermolide, isolated in microscopic quantities from a deep‐water sponge, shares the same microtubule‐stabilizing mechanism as Taxol and has a promising antitumor profile. There is, however, a chronic supply problem hampering clinical development and so a practical total synthesis of discodermolide is an important goal. This review highlights the completed total syntheses of discodermolide, focusing on the various methods and strategies employed for achieving stereocontrol and realising the pivotal fragment couplings. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)