bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ginkgolides and Glycine Receptors: A Structure–Activity Relationship Study
Authors: Jaracz Stanislav , Nakanishi Koji , Jensen Anders A. , Strømgaard Kristian 
Published: March 2004

AbstractGinkgolides from the Ginkgo biloba tree are diterpenes with a cage structure consisting of six five‐membered rings and a unique tBu group. They exert a variety of biological properties. In addition to being antagonists of the platelet activating factor receptor (PAFR), it has recently been shown that native ginkgolides are potent and selective antagonists of the inhibitory glycine receptor. Forty new ginkgolide derivatives have been prepared in good to high yields on milligram scales and investigated for their antagonistic properties at homomeric α1 glycine receptors, thus providing the first structure–activity relationship study of ginkgolides at glycine receptors. A high‐throughput screening assay showed that native ginkgolide C was the most potent ligand, and that manipulation of any of the hydroxyl groups led to loss of activity at α1 glycine receptors.
Structure and Lithium Dynamics of Li2AuSn2—A Ternary Stannide with Condensed AuSn4/2 Tetrahedra
Authors: Wu Zhiyun , Mosel Bernd D. , Eckert Hellmut , Hoffmann Rolf‐Dieter , Pöttgen Rainer 
Published: March 2004

AbstractThe new stannide Li2AuSn2 was prepared by reaction of the elements in a sealed tantalum tube in a resistance furnace at 970 K followed by annealing at 720 K for five days. Li2AuSn2 was investigated by X‐ray diffraction on powders and single crystals and the structure was refined from single‐crystal data: Z=4, I41/amd, a=455.60(7), c=1957.4(4) pm, wR2=0.0681, 278 F2 values, 10 parameters. The gold atoms display a slightly distorted tetrahedral tin coordination with AuSn distances of 273 pm. These tetrahedra are condensed through common corners leading to the formation of two‐dimensional AuSn4/2 layers. The latter are connected in the third dimension through SnSn bonds (296 pm). The lithium atoms fill distorted hexagonal channels formed by the three‐dimensional [AuSn2] network. Modestly small 7Li Knight shifts are measured by solid‐state NMR spectroscopy that are consistent with a nearly complete state of lithium ionization. The noncubic local symmetry at the tin site is reflected by a nuclear electric quadrupolar splitting in the 119Sn Mössbauer spectra and a small chemical shift anisotropy evident from 119Sn solid‐state NMR spectroscopy. Variable‐temperature static 7Li solid‐state NMR spectra reveal motional narrowing effects at temperatures above 200 K, revealing lithium atomic mobility on the kHz time scale. Detailed lineshape as well as temperature‐dependent spin lattice relaxation time measurements indicate an activation energy of lithium motion of 27 kJ mol−1.
Stereocontrolled Synthesis of the C21–C38 Fragment of the Unnatural Enantiomer of the Antibiotic Nystatin A1
Authors: Berkenbusch Thilo , Brückner Reinhard 
Published: March 2004

AbstractThe C21–C38 fragment all‐trans‐41 of the unnatural enantiomer 1 of nystatin A1 was prepared starting from the N‐propionyl oxazolidinone 9. Aldol adduct ent‐8 (ee > 96 %) derived in two steps was hydroborated with (thexyl)BH2. Oxidative work‐up and treatment with acid furnished δ‐lactone 4. It contains the complete stereotetrade of the target molecule. The α,β‐unsaturated ester 28 was reached after another four steps. It should be a precursor for the polyene moieties of a variety of polyol,polyene macrolides. Illustrating that, the α,β‐unsaturated aldehyde 29 obtained from 28 and DIBAL was extended by 10 C atoms in four steps yielding the C21–C38 segment 41. The latter set of transformations included the regio‐ and stereoselective Claisen rearrangement 32→35.
Oxasmaragdyrin–Ferrocene and Oxacorrole–Ferrocene Conjugates: Synthesis, Structure, and Nonlinear Optical Properties
Authors: Venkatraman Sundararaman , Kumar Rajeev , Sankar Jeyaraman , Chandrashekar Tavarekere K. , Sendhil Kaladevi , Vijayan C. , Kelling Alexandra , Senge Mathias O. 
Published: March 2004

AbstractFerrocenyl macrocyclic conjugates involving 22π oxasmaragdyrins and 18π oxacorroles have been synthesized and characterized. The direct covalent linkage of the ferrocenyl moiety to the meso position of the macrocycle is achieved by simple oxidative coupling of appropriate precursors with trifluoroacetic acid as catalyst. The electronic coupling between the ferrocenyl moiety and the macrocyclic π system is apparent from: a) the red shifts (293–718 cm−1) of the Soret and Q‐bands in the electronic absorption spectra of ferrocenyl conjugates; b) the shift of oxidation potentials (50–130 mV) of both the ferrocene and the corrole rings to the positive potentials; and c) considerable shortening of the CC bond which connects the ferrocene and the meso‐carbon atom of the macrocycle. The single‐crystal X‐ray structure of oxasmaragdyrin–ferrocene conjugate 9 reveals the planarity of the 22π skeleton with very small deviations of the meso‐carbon atoms. The meso‐ferrocenyl substituent has a small dihedral angle of 38°, making way for mixing of the molecular orbitals of the ferrocene and the macrocycle. However, the other two meso substituents are almost perpendicular to the mean plane, defined by the three meso carbon atoms. Classical CH⋅⋅⋅O and nonclassical CH⋅⋅⋅π interactions lead to a two‐dimensional supramolecular network. Ferrocene–smaragdyrin conjugate 9 bonds to a chloride ion in the protonated form and a rhodium(i) ion in the free base form. Nonlinear optical measurements reveal a larger nonlinear refractive index (−5.83×10−8 cm2 W−1) and figure of merit (2.28×10−8 cm3 W−1) for the rhodium smaragdyrin–ferrocene conjugate 19 than for the others, suggesting its possible application in optical devices.
Strategy for Enantio‐ and Diastereoselective Syntheses of All Possible Stereoisomers of 1,3‐Polyol Arrays Based on a Highly Catalyst‐Controlled Epoxidation of α,β‐Unsaturated Morpholinyl Amides: Application to Natural Product Synthesis
Authors: Tosaki Shin‐ya , Horiuchi Yoshihiro , Nemoto Tetsuhiro , Ohshima Takashi , Shibasaki Masakatsu 
Published: March 2004

AbstractWe describe a new strategy for enantio‐ and diastereoselective syntheses of all possible stereoisomers of 1,3‐polyol arrays. This strategy relies on a highly catalyst‐controlled epoxidation of α,β‐unsaturated morpholinyl amides promoted by the Sm–BINOL–Ph3AsO (1:1:1) complex, followed by a conversion of morpholinyl amides into ketones and diastereoselective ketone reduction. Highly enantio‐ (up to >99 % ee) or diastereoselective (up to >99.5:0.5) epoxidation was achieved using 5–10 mol % of the Sm complex to afford synthetically very useful, nearly optically pure α,β‐epoxy morpholinyl amides. Stereoselectivity of the epoxidation was controlled by the chirality of BINOL with overwhelming inherent diastereofacial preference for the substrate. Combination with the syn‐ and anti‐selective ketone reduction with the highly catalyst‐controlled epoxidation allowed for an iterative strategy for the syntheses of all possible stereoisomers of 1,3‐polyol arrays. Eight possible stereoisomers of 1,3,5,7‐tetraol arrays were synthesized with high to excellent stereoselectivity. Moreover, the efficiency of the present strategy was successfully demonstrated by enantioselective syntheses of several 1,3‐polyol/α‐pyrone natural products, for example, cryptocaryolone diacetate.
X‐chromosome loss of heterozygosity frequently occurs in gastrinomas and is correlated with aggressive tumor growth
Authors: Chen Yuan‐Jia , Vortmeyer Alexander , Zhuang Zhengping , Gibril Fathia , Jensen Robert T. 
Published: March 2004

AbstractBACKGROUNDRecent studies have shown that tumor growth, rather than hormone overproduction, is the leading cause of death among patients with gastrinomas and other malignant gastrointestinal endocrine tumors. No patient/laboratory characteristics accurately predict which tumors will exhibit aggressive growth. Furthermore, little is known regarding the molecular pathogenesis of these tumors. X‐chromosome loss of heterozygosity (LOH) occurs in some nonendocrine tumors, and its presence can be associated with aggressive growth/decreased survival. Data on X‐chromosome LOH in gastrointestinal endocrine tumors are conflicting. Therefore, the purpose of the current study was to determine whether X‐chromosome LOH occurred in gastrinomas and, if so, whether it was correlated with tumor growth, tumor behavior, and/or prognosis.METHODSX chromosome allelotyping was performed using 12 microsatallite markers spaced throughout the chromosome using DNA from leukocytes and microdissected gastrinoma specimens from 16 female patients. The presence of X‐chromosome LOH was analyzed for correlations with clinical and laboratory tumor characteristics as well as tumor growth characteristics.RESULTSNine gastrinoma specimens (56%) had X‐chromosome LOH, ranging from 6% to 23% at the 12 different loci studied. X‐chromosome LOH was significantly associated with aggressive postoperative tumor growth, increased primary tumor size, and pancreatic primaries. In 6 tumor specimens, LOH occurred on Xp22.1–22.3 over a 28.4‐centimorgan region.CONCLUSIONSX‐chromosome LOH was common in gastrinoma specimens from female patients, and its presence was found to be a potentially useful molecular/genetic prognostic factor for aggressive growth. Cancer 2004;100:1379–87. Published 2004 American Cancer Society.
Chromophobe renal cell carcinoma
Authors: Peyromaure Michaël , Misrai Vincent , Thiounn Nicolas , Vieillefond Annick , Zerbib Marc , Flam Thierry A. , Debré Bernard 
Published: March 2004

AbstractBACKGROUNDChromophobe renal cell carcinoma (CRCC) is often associated with a favorable prognosis. However, to the authors' knowledge, only few clinical data are available regarding this variant of tumor. In the current study, the authors report their experience with CRCC over the last 14 years.METHODSSince 1989, 61 patients have been treated at the study institution for CRCC. Tumor characteristics and patient outcome were analyzed retrospectively. Data were obtained from the patients' medical records.RESULTSThe mean age of the patients was 58 years. Of the 61 tumors, 68.8% were discovered incidentally. The mean tumor size was 6.9 cm. Fifty‐seven patients (93.4%) were treated with radical nephrectomy and 4 patients (6.6%) underwent partial nephrectomy. According to the 1997 TNM classification, the pathologic tumor stage was T1 in 65.6% of cases, T2 in 31.1% of cases, and T3a in 3.3% of cases. All tumors were staged as N0M0. Nuclear grade was low (1 or 2) in 88.5% of cases. In no case of CRCC was a sarcomatoid component observed. At a mean follow‐up of 49.5 months (range, 5–135 months), no patient had experienced tumor recurrence or disease progression, and none had died of renal carcinoma.CONCLUSIONSIn the authors' experience, CRCC carries an excellent prognosis, possibly due to the high rate of low‐stage and low‐grade tumors. Cancer 2004;100:1406–10. © 2004 American Cancer Society.
Interleukin‐1 (IL‐1α and IL‐1β) and its receptors (IL‐1RI, IL‐1RII, and IL‐1Ra) in prostate carcinoma
Authors: Ricote Mónica , García‐Tuñón Ignacio , Bethencourt Fermín R. , Fraile Benito , Paniagua Ricardo , Royuela Mar 
Published: March 2004

AbstractBACKGROUNDThe principal components of the interleukin‐1 (IL‐1) family are two secreted factors (IL‐1α and IL‐1β), two transmembrane receptors (IL‐1RI [biologically active] and IL‐1RII [inert receptor]), and a natural antagonist receptor of IL‐1 function (IL‐1Ra). Changes in the expression pattern of these IL‐1 members have been reported to be related to disease progression. The objective of the current study was to evaluate these changes in prostatic tissue by means of immunohistochemistry and Western blot analysis.METHODSImmunohistochemical and Western blot analyses were performed in 20 normal samples, 35 samples of benign prostatic hyperplasia (BPH) and 27 samples from patients with prostate carcinoma (PC).RESULTSIn normal prostate samples, immunoreactions to IL‐1β and IL‐1RI were positive, whereas there were no immunoreactions observed to IL‐1α, IL‐1RII, or IL‐1Ra. In BPH, in addition to immunoreactions to IL‐1β and IL‐1RI, immunoreactions to IL‐1α, IL‐1RII, and IL‐1Ra were observed in many samples. In samples of PC with low Gleason grade, most tumors had positive immunoreactions to IL‐1α and IL‐1RI. In samples of PC with high Gleason grade, immunoreactions were seen only to IL‐1α, IL‐1RI, and IL‐1RII.CONCLUSIONSThe current results suggested that high expression levels of IL‐1α and IL1‐RI in epithelial cells in BPH and PC samples were involved in cell proliferation and that the loss of immunoexpression of IL‐1β and IL‐1Ra was a characteristic feature of PC compared with normal prostate samples and BPH. Because this loss is progressive up to a complete absence of immunoexpression in PC of high Gleason grade, the evaluation of IL‐1β and IL‐1Ra in PC may be significant in assessing for malignancy. Cancer 2004;100:1388–96. © 2004 American Cancer Society.
Anthropometric variables, physical activity, and incidence of ovarian cancer
Authors: Anderson Jeffrey P. , Ross Julie A. , Folsom Aaron R. 
Published: March 2004

AbstractBACKGROUNDReports on the relation between anthropometric variables (height, weight) and physical activity with ovarian cancer have been inconclusive. The objective of the current study was to extend investigation of potential associations in the Iowa Women's Health Study cohort.METHODSThe relation between self‐reported anthropometric variables and incident ovarian cancer was studied in a prospective cohort of women ages 55–69 years who were followed for 15 years. Two hundred twenty‐three incident cases of epithelial ovarian cancer were identified by linkage to a cancer registry.RESULTSNo association was found overall between ovarian cancer and height, but a positive association was observed for serous ovarian cancers (relative risk [RR], 1.86 for highest quartile vs. lowest quartile; 95% confidence interval [95% CI], 1.06–3.29). Although current body mass index (BMI) was not associated with ovarian cancer, a BMI ≥ 30 kg/m2 at age 18 years appeared to be associated positively with ovarian cancer (multivariate‐adjusted RR, 1.83 for BMI ≥ 30 kg/m2 vs. BMI < 25 kg/m2; 95% CI, 0.90–3.72), and this association was stronger after exclusion of the first 2 years of follow‐up (RR, 2.15; 95% CI, 1.05–4.40). In a multivariate analysis, waist‐to‐hip ratio was associated with ovarian cancer (RR, 1.59 for highest quartile vs. lowest quartile; 95% CI, 1.05–2.40), but a linear dose response was not found. An index that combined the frequency and intensity of leisure‐time physical activity was associated positively with ovarian cancer incidence (multivariate‐adjusted RR, 1.42 for high activity vs. low activity; 95% CI, 1.03–1.97). This association was particularly strong for frequency of vigorous physical activity (multivariate‐adjusted RR, 2.38 for > 4 times per week vs. rarely/never; 95% CI, 1.29–4.38).CONCLUSIONSAnthropometric variables were not major risk factors for ovarian cancer in the cohort studied; however, high BMI in early adulthood and frequent and vigorous physical activity may increase the risk of ovarian cancer among postmenopausal women. Cancer 2004;100:1515–21. © 2004 American Cancer Society.
Low‐curvature image simplifiers: Global regularity of smooth solutions and Laplacian limiting schemes
Authors: Bertozzi Andrea L. , Greer John B. 
Published: March 2004

AbstractWe consider a class of fourth‐order nonlinear diffusion equations motivated by Tumblin and Turk's “low‐curvature image simplifiers” for image denoising and segmentation. The PDE for the image intensity u is of the form

where g(s) = k2/(k2 + s2) is a “curvature” threshold and λ denotes a fidelity‐matching parameter. We derive a priori bounds for Δu that allow us to prove global regularity of smooth solutions in one space dimension, and a geometric constraint for finite‐time singularities from smooth initial data in two space dimensions. This is in sharp contrast to the second‐order Perona‐Malik equation (an ill‐posed problem), on which the original LCIS method is modeled. The estimates also allow us to design a finite difference scheme that satisfies discrete versions of the estimates, in particular, a priori bounds on the smoothness estimator in both one and two space dimensions. We present computational results that show the effectiveness of such algorithms. Our results are connected to recent results for fourth‐order lubrication‐type equations and the design of positivity‐preserving schemes for such equations. This connection also has relevance for other related fourth‐order imaging equations. © 2004 Wiley Periodicals, Inc.
Syntheses and Morphologies of Carbon Microsolenoid Composites and Double Negative Microcoils
Authors: Yang S. , Chen X. , Motojima S. 
Published: March 2004

AbstractNovel carbon microsolenoid composites with central straight nanopores along the coil axes and double negative microcoils with helically formed nanopores along the fiber axes were prepared by a two‐step CVD process using carbon microcoil (CMC) templates. The as‐grown CMC templates were synthesized at 780 °C, and the pyrolytic carbon layer (Py‐C) was coated in‐situ at 860 °C on the surface, then the core CMCs were preferentially oxidized at 700 °C for 10 min in air. In the carbon microsolenoids, the straight, central nanopores, with a diameter of 0–600 nm, were derived from the central pores existing along the coil axis of the source, regularly‐coiled CMC templates, while the double negative microcoils were derived from the burnt‐out core CMC templates in the carbon microsolenoids. The morphology and microstructure of the novel carbon materials were observed and analyzed using scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetry (TG), and X‐ray diffraction (XRD).
Atomic Layer Deposition of Hafnium Dioxide Films from Hafnium Hydroxylamide and Water
Authors: Kukli K. , Ritala M. , Leskelä M. , Sajavaara T. , Keinonen J. , Jones A.C. , Tobin N.L. 
Published: March 2004

AbstractHfO2 films were grown by atomic layer deposition (ALD) from a new liquid precursor, Hf(ONEt2)4 and H2O, at temperatures between 250 °C and 350 °C on borosilicate glass and Si(100) substrates. The highest growth rate was achieved at 300 °C, whereas the growth was essentially slower at 250 °C and ceased at 350 °C. The films possessed an O:Hf ratio of 2.15 ± 0.12, as determined by ion beam analysis. The films were weakly crystallized, showing X‐ray diffraction (XRD) peaks characteristic of monoclinic phase. The refractive index of the films varied between 1.93 and 1.96. The effective permittivities of the dielectric layers in Al/HfO2/n‐Si(100) capacitor structures were close to 10.
A linkage study of 12 IDDM susceptibility loci in the Finnish population
Authors: Laine Antti‐Pekka , Nejentsev Sergei , Veijola Riitta , Korpinen Eija , Sjöroos Minna , Simell Olli , Knip Mikael , Åkerblom Hans K , Ilonen Jorma 
Published: March 2004

AbstractBackgroundHLA region is the major locus (IDDM1) of type 1 diabetes (T1D) susceptibility. It explains approximately 50% of the genetic background of T1D, indicating additional genetic determinants. Genome scans and candidate gene studies have generated several chromosomal candidate regions that may have a role in T1D development.MethodsWe tested 12 of these loci for linkage in 107 Finnish T1D multiplex families using 23 microsatellite markers and 2 SNPs. Families were stratified according to the HLA status and sharing at the DQB1 gene.ResultsWe found no significant or suggestive MLS in our unstratified families outside the IDDM1 locus. The highest MLS was seen close to the IDDM9 region marker D3S3576 at 3q21‐q25 (MLS = 1.05). This marker also had a global p‐value of 0.0032 (ETDT) in maternal transmissions. IDDM6 and 12q12‐q15 region showed MLS = 1.1 and MLS = 1.3 respectively in HLA‐DQB1*0302/x (x ≠ HLA − DQB1*02) stratified families. IDDM12 showed MLS = 2.0 in HLA‐DQB1 identical sib pairs. Linkage at IDDM12 was supported by a global p‐value of 0.0006 (uncorrected) in ETDT. For IDDM2, p‐values of 0.028 and 0.009 were observed in ETDT with MspI – 2221 SNP in unstratified and HLA‐DQB1*0302/x‐stratified families respectively.ConclusionsOur results are consistent with previous findings of linkage or association to T1D at IDDM2, IDDM6, IDDM9, IDDM12 and 12q12‐q15 regions but do not unambiguously confirm them. A larger sample set is required to gain statistical power needed to confirm our findings in the Finnish population. Copyright © 2004 John Wiley & Sons, Ltd.
Longer breastfeeding is an independent protective factor against development of type 1 diabetes mellitus in childhood
Authors: Sadauskaitė‐Kuehne Vaiva , Ludvigsson Johnny , Padaiga Žilvinas , Jašinskienė Edita , Samuelsson Ulf 
Published: March 2004

AbstractBackgroundEarly weaning diet, early introduction of breast milk substitution and cow's milk have been shown to increase the risk of type 1 diabetes later in life. It is also shown that older maternal age, maternal education, preeclampsia, prematurity, neonatal illness and neonatal icterus caused by blood group incompatibility, infections and stress might be risk factors for type 1 diabetes. We aimed to determine whether early nutrition is an independent risk factor for diabetes despite other life events.MethodsData from 517 children (268 boys and 249 girls) in south‐east of Sweden and 286 children (133 boys and 153 girls) in Lithuania in the age group of 0 to 15 years with newly diagnosed type 1 diabetes mellitus were included into analysis. Three age‐ and sex‐matched healthy controls were randomly selected. Response rate in control families in Sweden was 72.9% and in Lithuania 94.8%. Information was collected via questionnaires.ResultsExclusive breastfeeding longer than five months (odds ratio 0.54, 95% confidence interval 0.36–0.81) and total breastfeeding longer than 7 (0.56, 0.38–0.84) or 9 months (0.61, 0.38–0.84), breastfeeding substitution that started later than the third month (0.57, 0.33–0.98) among Swedish children 5 to 9 years old and later than the seventh month (0.24, 0.07–0.84) among all Swedish children is protective against diabetes when adjusted for all other above‐listed risk factors. In Lithuania, exclusive breastfeeding longer than two months in the age group of 5 to 9 years is protective (0.58, 0.34–0.99) when adjusted for other factors.ConclusionsLonger exclusive and total breastfeeding appears as an independent protective factor against type 1 diabetes. Copyright © 2004 John Wiley & Sons, Ltd.