bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chemical Oxidation of 1,3,2‐Diazaboroles and 1,3,2‐Diazaborolidines
Authors: Weber Lothar , Domke Imme , Kahlert Jan , Stammler Hans‐Georg 
Published: July 2006

AbstractOxidation of the 1,3,2‐diazaborole tBuNaCH=CHNb(tBu)BBr(Na–B) (1h) with NO+PF6– afforded the diazaborolium salts [tBuNa=CH–CH=Nb(tBu)BF2(Na–B)]+X– (X = Br–, Br3–, PF6–) (3h) as the result of different oxidation processes. The same product was obtained when the 1,3,2‐diazaborolidine tBuNaCH2CH2Nb(tBu)BBr(Na–B) (2h) was subjected to reaction with NO+PF6–. In contrast to this, oxidation of 1h and 2h with NO+BF4– cleanly furnished [tBuNaCH–CH=Nb(tBu)BFBr(Na–B)]+BF4– (6h). Treatment of the 1,3,2‐diazaboroles tBuNaCH=CHNb(tBu)BR(Na–B) [R = H (1e), CN (1i), C≡CH (1j)] with NO+PF6– under comparable conditions led to the borolium salts [tBuNa=CH–CH=Nb(tBu)BRF(Na–B)]+PF6– [R = H (3e), CN (3i), C≡CH (3j)]. All the borolium salts investigated in this study were reversibly reduced by cyclic voltammetry. The novel products were characterized by elemental analyses and NMR spectra (1H, 11B, 13C, 19F, 31P). The X‐ray structure analysis of 3h reveals two independent planar cations in the asymmetric unit, accompanied by one bromide and one tribromide ion.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Formation of a Series of [{Methylphenylenebis(terpyridine)}nRuIIn–1] (n = 2–6) Oligomers in a Single‐Pot Reaction
Authors: Cho Tae Joon , Moorefield Charles N. , Hwang Seok‐Ho , Wang Pingshan , Godínez Luis A. , Bustos Erika , Newkome George R. 
Published: July 2006

AbstractA series of oligomeric [{methylphenylenebis(terpyridine)}nRuIIn–1] complexes, where n = 2–6, possessing metal‐free terpyridine end groups was formed and isolated from a single‐pot reaction. These oligo complexes were analyzed by 1H NMR spectroscopy and mass spectrometry. Macrocyclization of combinations of these oligomers gave rise to the known hexagonal metallomacrocycle 7. Cyclic voltammetry (CV) data of these linear oligomers are discussed and compared to that of the corresponding metallomacrocycle 7. Diffusion coefficients were obtained by means of the Randles–Sevcik equation.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Hyporheic exchange flows induced by constructed riffles and steps in lowland streams in southern Ontario, Canada
Authors: Kasahara Tamao , Hill Alan R. 
Published: July 2006

AbstractStream–subsurface water interaction induced by natural riffles and constructed riffles/steps was examined in lowland streams in southern Ontario, Canada. The penetration of stream water into the subsurface was analysed using hydrometric data, and the zone of > 10% stream water was calculated from a chemical mixing equation using tracer injection of bromide and background chloride concentrations. The constructed riffles studied induced more extensive hyporheic exchange than the natural riffles because of their steeper longitudinal hydraulic head gradients and coarser streambed sediments. The depth of > 10% stream water zone in a small and a large constructed riffle extended to > 0·2 m and > 1·4 m depths respectively. Flux and residence time distribution of hyporheic exchange were simulated in constructed riffles using MODFLOW, a finite‐difference groundwater flow model. Hyporheic flux and residence time distribution varied along the riffles, and the exchange occurring upstream from the riffle crest was small in flux and had a long residence time. In contrast, hyporheic exchange occurring downstream from the riffle crest had a relatively short residence time and accounted for 83% and 70% of total hyporheic exchange flow in a small and large riffle respectively. Although stream restoration projects have not considered the hyporheic zone, our data indicate that constructed riffles and steps can promote vertical hydrologic exchange and increase the groundwater–surface water linkage in degraded lowland streams. Copyright © 2006 John Wiley & Sons, Ltd.
Combination of cytosine deaminase with uracil phosphoribosyl transferase leads to local and distant bystander effects against RM1 prostate cancer in mice
Authors: Khatri Aparajita , Zhang Bing , Doherty Eboney , Chapman Jane , Ow Kim , Pwint Hnin , Martiniello‐Wilks Rosetta , Russell Pamela J. 
Published: July 2006

AbstractBackgroundWe aimed to evaluate the efficacy of gene‐directed enzyme‐prodrug therapy (GDEPT) using cytosine deaminase in combination with uracil phosphoribosyl transferase (CDUPRT) against intraprostatic mouse androgen‐refractory prostate (RM1) tumors in immunocompetent mice. The product of the fusion gene, CDUPRT, converts the prodrug, 5‐fluorocytosine (5FC), into 5‐fluorouracil (5FU) and other cytotoxic metabolites that kill both CDUPRT‐expressing and surrounding cells, via a ‘bystander effect’.MethodsStably transformed andogen‐independent mouse prostate cancer (PC) cells, RM1‐CDUPRT, ‐GFP or GFP/LacZ cells were used. To assess the local bystander effects of CDUPRT‐GDEPT, immunocompetent C57BL/6 mice implanted with cell mixtures of RM1‐GFP/CDUPRT and RM1‐GFP cells in different proportions intraprostatically were treated with 5FC. Pseudo‐metastases in the lungs were established by a tail vein injection of untransfected RM1 cells. At necropsy, prostate weight/volume and lung colony counts were assessed. Tumors, lymph nodes, spleens and lungs were frozen or fixed for immunohistochemistry.ResultsCDUPRT expression in RM1‐GFP/CDUPRT cells or tumors was confirmed by enzymic conversion of 5FC into 5FU, using HPLC. Treatment of mice bearing intraprostatic RM1‐GFP/CDUPRT tumors with 5FC resulted in complete regression of the tumors. A ‘local bystander effect’ was seen, even though only 20% of the cells expressed CDUPRT. More importantly a significant reduction in pseudo‐metastases of RM1 cells in lungs indicated a ‘distant bystander effect’. Immunohistochemical evaluation of the treated tumors showed increased necrosis and apoptosis, with decreased tumor vascularity. There was also a significant increase in tumour‐infiltration by macrophages, CD4+ T and natural killer cells.ConclusionsWe conclude that CDUPRT‐GDEPT significantly suppressed the aggressive growth of RM1 prostate tumors and lung pseudo‐metastases via immune mechanisms involving necrosis and apoptosis. Copyright © 2006 John Wiley & Sons, Ltd.
Acoustic methods of detection in gas chromatography
Authors: Mah Christine , Thurbide Kevin B. 
Published: July 2006

AbstractA brief review of the use of acoustic detection methods in GC is presented. While a number of methods (some quite similar) have been developed for use as gas‐phase sensors in various applications, this article focuses specifically on those techniques that have been used to detect analytes following their separation by GC. Overall, a number of “active” acoustic methods (which measure analytes through their interaction with a controlled external acoustic wave source) were reportedly used as GC detectors. These include ultrasonic, thickness shear mode, surface acoustic wave (SAW), and flexural plate wave methods. Conversely, “passive” acoustic methods (those that produce an acoustic signal through some chemical reaction with the analyte) have also been used as GC detectors. These include photoacoustic and acoustic flame methods of detection. Of the two major classifications, reports of active methods are far more prevalent. In particular, the usage of SAW techniques with GC is an area of research that has seen accelerated growth in recent years.
Affinity monolith chromatography
Authors: Mallik Rangan , Hage David S. 
Published: July 2006

AbstractThe combined use of monolithic supports with selective affinity ligands as stationary phases has recently given rise to a new method known as affinity monolith chromatography (AMC). This review will discuss the basic principles behind AMC and examine the types of supports and ligands that have been employed in this method. Approaches for placing affinity ligands in monoliths will be considered, including methods based on covalent immobilization, biospecific adsorption, entrapment, and the formation of coordination complexes. Several reported applications will then be presented, such as the use of AMC for bioaffinity chromatography, immunoaffinity chromatography, immobilized metal‐ion affinity chromatography, dye‐ligand affinity chromatography, and biomimetic chromatography. Other applications that will be discussed are chiral separations and studies of biological interactions based on AMC.
Applications of nanomaterials in liquid chromatography: Opportunities for separation with high efficiency and selectivity
Authors: Zhang Zhengxiang , Wang Zhiyong , Liao Yiping , Liu Huwei 
Published: July 2006

AbstractDuring recent decades, great efforts have been made to improve the chemical stability, selectivity, and separation efficiency of stationary phases in liquid chromatography. Significant progress has been achieved, especially after the introduction of nanomaterials into separation science. This review covers the applications of nanomaterials playing various roles in liquid chromatography. Future possibilities for developing nanomaterial‐based stationary phases are also discussed.
Local approximations and intrinsic characterization of spaces of smooth functions on regular subsets of ℝn
Authors: Shvartsman Pavel 
Published: July 2006

AbstractWe give an intrinsic characterization of the restrictions of Sobolev $W^{k}_{p}$ (ℝn ), Triebel–Lizorkin $F^{s}_{pq}$(ℝn ) and Besov $B^{s}_{pq}$(ℝn ) spaces to regular subsets of ℝn via sharp maximal functions and local approximations. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
7Li and 13C solid‐state NMR spectra of lithium cuprates
Authors: Jost Steffen , Kühnen Martin , Günther Harald 
Published: July 2006

Abstract7Li and 13C solid‐state MAS NMR spectra of three lithium cuprates with known X‐ray structures—lithium([12]crown‐4)2 dimethyl and diphenyl cuprate (1,2) and lithium(thf)4‐[tris(trimethylsilyl) methyl]2 cuprate (3)—have been measured and analysed with respect to the quadrupolar coupling constants of lithium‐7, χ(7Li), and the asymmetry parameters of the quadrupolar interactions, η(7Li), as well as the 6, 7Li and 13C chemical shifts. The χ(7Li) values of 23, 30, and 18 kHz for 1, 2 and 3, respectively, are in line with the high symmetry around the lithium nucleus in the solvent‐separated structures and may be used as reference data for this structural motif. Calculations based on charges derived from ab initio 6‐31 G* HF computations using the point charge model (PCM) and the program GAMESS support the experimental findings. Copyright © 2006 John Wiley & Sons, Ltd.
Complete 1H and 13C NMR assignments of clerodane diterpenoids of Salvia splendens
Authors: Fontana Gianfranco , Savona Giuseppe , Rodríguez Benjamín 
Published: July 2006

AbstractUnambiguous and complete assignments of 1H and 13C NMR chemical shifts for five clerodane diterpenes, four of them isolated from Salvia splendens (salviarin, splendidin and splenolides A and B) and one obtained by acetylation of splenolide A, are presented. The assignments are based on 2D shift‐correlated [1H,1H–COSY, 1H,13C‐gHSQC–1J(C,H) and 1H,13C‐gHMBC‐nJ(C,H) (n = 2 and 3)] and nuclear Overhauser effect (NOE) experiments. The conformation of the rings of these compounds is supported by the 3J(H,H) values and NOE results. Copyright © 2006 John Wiley & Sons, Ltd.
Assignments of 1H and 13C NMR spectral data for ondansetron and its two novel metabolites, 1‐hydroxy‐ondansetron diastereoisomers
Authors: Duan Mingyu , Huang Haihua , Li Xinnan , Chen Xiaoyan , Zhong Dafang 
Published: July 2006

AbstractAssignments of 1H and 13C NMR chemical shifts were made by means of heteronuclear single quantum coherence (HSQC) and heteronuclear multiple bond correlation (HMBC) experiments for ondansetron, and by means of 1H‐1H correlation spectroscopy (1H‐1H COSY) and two‐dimensional nuclear Overhauser effect spectroscopy (NOESY) experiments for two novel metabolites (M1 and M2) of ondansetron. These two metabolites were isolated for the first time from Mucor circinelloides. Copyright © 2006 John Wiley & Sons, Ltd.
Eosinophilic chromophobe renal cell carcinoma in a child with hypospadias
Authors: Campus Riccardo , Nozza Paolo , Dell'Acqua Anna , Sementa Angela R. , Gambini Claudio , Dodero Paolo 
Published: July 2006

AbstractChromophobe renal cell carcinoma (CRCC) is a distinct variant of renal carcinoma generally affecting adults. We report a case of an unusual CRCC, arising in a male child affected by hypospadias. This case demonstrates that CRCC can occur in the pediatric patients and can be associated with genital tract anomalies such as Wilms tumor. Pediatr Blood Cancer 2008;50:413–415. © 2006 Wiley‐Liss, Inc.
The utility assessment of Chinese pregnant women towards the birth of a baby with Down syndrome compared to a procedure‐related miscarriage
Authors: Chan Yiu Man , Leung Tse Ngong , Leung Tak Yeung , Fung Tak Yuen , Chan Lin Wai , Lau Tze Kin 
Published: July 2006

AbstractObjectiveThis study was performed to investigate the preferences of Chinese pregnant women for Down syndrome‐affected birth compared to invasive test‐related miscarriage, using the standard gamble approach, and to investigate whether there is a difference in Utility Score between general obstetric patients and those who request prenatal screening.MethodsAn interviewer‐administered survey was conducted on 67 women who presented to the General Obstetric Clinic for booking visits and 69 women who presented to the first‐trimester Combined Screening Clinic for fetal Down syndrome in a University Obstetric Unit. Preferences for Down syndrome‐affected birth compared to invasive test‐related miscarriage were assessed using the standard gamble approach. The differences in Utility Scores for the two outcomes and difference in scores between the two study groups were compared.ResultsThere was no significant difference in any of the Utility Scores studied between the two study groups. Therefore the summary statistics were performed using the whole study population. The median Utility Score for a Down syndrome‐birth was 0.20 (IQR: 0.10–0.40), which was significantly lower than that of 0.55 (IQR: 0.40–0.80) for a procedure‐related miscarriage (p < 0.001). Also, the Utility Scores were neither found to be associated with any particular patient demographic characteristics nor their perception of the functional disability of individuals with Down syndrome.ConclusionThe Chinese pregnant women in Hong Kong consider a Down syndrome‐affected birth as a much worse health state and life event than a miscarriage. Whether or not to have a screening test appeared to be a result of accessibility and affordability rather than fundamental differences in attitude towards Down syndrome. The findings of the study provide important information on how prenatal screening and diagnosis of fetal chromosomal abnormalities should be offered. Copyright © 2006 John Wiley & Sons, Ltd.
Klippel‐Trenaunay‐Weber syndrome involving fetal thigh: prenatal presentations and outcomes
Authors: Peng Hsiu‐Huei , Wang Tzu‐Hao , Chao An‐Shine , Chang Yao‐Lung , Shieh Shin‐Chih , Chang Shuenn‐Dyh 
Published: July 2006

AbstractObjectivesWe analyzed the prenatal presentations and perinatal outcomes of Klippel‐Trenaunay‐Weber syndrome involving fetal thigh in order to provide relevant information for prenatal counseling.MethodsWe reviewed our own cases and searched for cases from Medline that met the criteria of Klippel‐Trenaunay‐Weber syndrome involving fetal thigh. Those with isolated hemangioma, hemangioendothelioma, and hemangiolymphangioma were excluded.ResultsThe cases of Klippel‐Trenaunay‐Weber syndrome involving fetal thigh, totaling 21, were collected for analysis. These included 19 cases from Medline search and two cases from our institution. The cases with lesions involving right thigh, left thigh, and both thighs were 12:8:1. The gender of affected fetuses was 9 male, 9 female, and 3 unknown. Among the 21 cases, 6 fetuses (28.57%, 6/21) had isolated thigh lesions, and the other 15 cases (71.43%, 15/21) had extensive lesions involving pelvis, abdomen, retroperitoneum, or thorax. Prenatal presentations varied with hypoechoic cystic mass with limb asymmetry, 95.23% (20/21); polyhydramnios, 38.09% (8/21); cardiomegaly, 19.04% (4/21); thick placenta, 9.52% (2/21); nonimmune hydrops fetalis, 9.52% (2/21); and oligohydramnios, 4.76% (1/21). Ten cases (47.62%, 10/21) underwent termination of pregnancy. For those who continued with pregnancy, the rate of complications with Kasabach‐Merritt syndrome was 36.36% (4/11) and the mortality rate in the neonatal period was 45.45% (5/11). The causes of neonatal mortality in these five cases included consumption coagulopathy (Kasabach‐Merritt syndrome), cardiac failure, sepsis, and prematurity.ConclusionsKlippel‐Trenaunay‐Weber syndrome involving fetal thigh is rare. Our review showed that the location of involvement on the right thigh is more than on the left. Males and females were equally affected. Nearly three fourths of the cases had extensive involvement over other parts of the body. Prenatal ultrasound finding of a raised thigh mass of significant size and limb asymmetry were the most important features. The mortality rate was as high as 45.45% in the neonatal period. Copyright © 2006 John Wiley & Sons, Ltd.
A prospective analysis of cell‐free fetal DNA concentration in maternal plasma as an indicator for adverse pregnancy outcome
Authors: Bauer Margit , Hutterer Georg , Eder Martina , Majer Sandra , LeShane Erik , Johnson Kirby L. , Peter Inga , Bianchi Diana W. , Pertl Barbara 
Published: July 2006

AbstractObjectivesTo evaluate whether cell‐free fetal (cff) DNA in maternal plasma during the second trimester is a marker for developing pregnancy‐associated complications. Two PCR techniques for the detection and quantitation of fetal DNA were compared.MethodsPlasma samples were prospectively collected from 84 pregnant women carrying male fetuses before amniocentesis (14–29 weeks). We later recorded 26 pregnancies with complicated outcomes, including five cases of fetal chromosomal abnormalities. For statistical analysis, two overlapping subgroups A and B were made. Each group was separately compared for total and fetal DNA with a corresponding group considered normal using Wilcoxon rank sum test. Male fetal DNA concentration in maternal plasma was quantified using real‐time quantitative polymerase chain reaction (PCR) of SRY sequences. The samples were also analyzed by quantitative fluorescent PCR (QF‐PCR) using highly polymorphic short tandem repeat DNA sequences (STRs), and the percentage of relative fetal allele concentration in maternal alleles was calculated and compared to the fetal/total DNA ratio obtained by real‐time PCR.ResultsQuantities of total and fetal circulating DNA were significantly correlated (r2 = 0.44, P < 0.0001) with a median total DNA concentration of 522 GE/mL (range 51–3047) and a median fetal DNA concentration of 8 GE/mL (range 0–879). Neither level was correlated with gestational age in pregnancies with normal (r2 = −0.05; P = 0.66, and r2 = 0.02; P = 0.88, respectively) and abnormal (r2 = 0.45; P = 0.17, and r2 = 0.11; P = 0.76, respectively) outcomes. Although both total and fetal DNA levels were always higher in women carrying pregnancies with chromosomal aberrations or having other pregnancy complications (P‐values range from 0.028 to 0.267), these differences reached statistical significance only for total DNA levels between the group A and corresponding normal pregnancies (P = 0.028). The correlation between the fetal/total DNA ratio obtained by real‐time PCR and the percentage of relative fetal allele concentration in maternal alleles obtained by QF‐PCR was not found to be statistically significant (r2 = 0.04; P = 0.76).ConclusionOur results confirm the clinical value of fetal DNA measurement in maternal plasma during the second trimester as a supplement for the diagnosis of aneuploidies. Its use as a screening instrument for complications that develop later in pregnancy seems to be limited but needs further investigation.Although the QF‐PCR assay has the advantage of being applicable to both female and male fetuses, this approach cannot be used for quantitation of cff DNA in maternal plasma samples. Copyright © 2006 John Wiley & Sons, Ltd.
Sulfonated silica‐based electrolyte nanocomposite membranes
Authors: Gomes Dominique , Buder Irmgard , Nunes Suzana P. 
Published: July 2006

AbstractNew functionalized particles were prepared by attaching sulfonated aromatic bishydroxy compounds onto fumed silica surface. First, a bromophenyl group was introduced onto the silica surface by reaction of bromophenyltrimethoxysilane with fumed silica. Then, sulfonated bishydroxy aromatic compounds were chemically attached to the silica surface by nucleophilic substitution reactions. The structure of the modified silica was characterized by elemental analysis: 13C‐NMR, 29Si‐NMR, and FTIR. Afterward, novel inorganic–organic electrolyte composite membranes based on sulfonated poly(ether ether ketone) have been developed using the sulfonated aromatic bishydroxy compounds chemically attached onto the fumed silica surface. The composite membrane prepared using silica with sulfonated hydroxytelechelic, containing 1,3,4‐oxadiazole units, has higher proton conductivity values in all range of temperatures (40–140 °C) than the membrane containing only the plain electrolyte polymer, while the methanol permeability determined by pervaporation experiment was unchanged. A proton conductivity up to 59 mS cm−1 at 140 °C was obtained. The combination of these effects may lead to significant improvement in fuel cells (fed with hydrogen or methanol) at temperatures above 100 °C. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 2278–2298, 2006
Exploring the environmental preference of weak interactions in (α/β)8 barrel proteins
Authors: Chakkaravarthi S. , Babu M. Madan , Gromiha M. Michael , Jayaraman G. , Sethumadhavan R. 
Published: July 2006

AbstractThe environmental preference for the occurrence of noncanonical hydrogen bonding and cation–π interactions, in a data set containing 71 nonredundant (α/β)8 barrel proteins, with respect to amino acid type, secondary structure, solvent accessibility, and stabilizing residues has been performed. Our analysis reveals some important findings, which include (a) higher contribution of weak interactions mediated by main‐chain atoms irrespective of the amino acids involved; (b) domination of the aromatic amino acids among interactions involving side‐chain atoms; (c) involvement of strands as the principal secondary structural unit, accommodating cross strand ion pair interaction and clustering of aromatic amino acid residues; (d) significant contribution to weak interactions occur in the solvent exposed areas of the protein; (e) majority of the interactions involve long‐range contacts; (f) the preference of Arg is higher than Lys to form cation–π interaction; and (g) probability of theoretically predicted stabilizing amino acid residues involved in weak interaction is higher for polar amino acids such as Trp, Glu, and Gln. On the whole, the present study reveals that the weak interactions contribute to the global stability of (α/β)8 TIM‐barrel proteins in an environment‐specific manner, which can possibly be exploited for protein engineering applications. Proteins 2006. © 2006 Wiley‐Liss, Inc.