bluuebunny/crossref_metadata_2025_split huggingface dataset:
An epidermal nevus syndrome with cerebral involvement caused by a mosaic FGFR3 mutation
Authors: García‐Vargas Alejandro , Hafner Christian , Pérez‐Rodríguez Adriana G. , Rodríguez‐Rojas L. Ximena , González‐Esqueda Pedro , Stoehr Robert , Hernández‐Torres Mercedes , Happle Rudolf 
Published: July 2008

AbstractA 5‐year‐old Mexican girl had a bilateral, systematized epidermal nevus of a non‐epidermolytic, non‐organoid type covering large parts of her body with the exception of the scalp. Clinically, this nevus was of a soft, velvety type showing affinity to the large body folds. Histopathological examination revealed orthohyperkeratosis and papillomatosis without granular degeneration and without any abnormality of adnexal structures. During infancy she developed seizures, and subsequently a delayed mental development was noted. Computer tomography of the brain revealed cortical and subcortical atrophy, a subdural hygroma in the left frontoparietotemporal region, and hypoplasia of corpus callosum. Molecular analysis of a biopsy specimen obtained from the epidermal nevus revealed a heterozygous R248C hotspot mutation in FGFR3, whereas in normal skin the FGFR3 wild‐type allele was exclusively found. The R248C mutation was also present in DNA extracted from blood leukocytes. Because FGFR3 is involved in the development of the central nervous system, the clinical and genetic findings of this case indicate a widespread mosaicism of the FGFR3 mutation. This unusual mosaic phenotype may represent a distinct entity within the group of epidermal nevus syndromes. © 2008 Wiley‐Liss, Inc.
Gas‐ und Dampfsensoren auf der Basis von Kohlenstoff‐Nanoröhren
Authors: Kauffman Douglas R. , Star Alexander 
Published: July 2008

AbstractSeit ihrer Entdeckung im Jahr 1991 haben Kohlenstoff‐Nanoröhren ein riesiges Interesse erfahren. Grund ist ihr enormes Anwendungspotenzial, und Forscher unterschiedlicher Fachrichtungen arbeiten heute gemeinsam daran, die elektronische Struktur und das Reaktionsverhalten von Kohlenstoff‐Nanoröhren aufzuklären. Da ihre elektronische Struktur leicht von wechselwirkenden Molekülen beeinflusst wird, reagieren Kohlenstoff‐Nanoröhren extrem empfindlich auf Änderungen in der lokalen chemischen Umgebung. Dies macht sie zu idealen Kandidaten für den Einsatz in chemischen Sensoren, und es wurden bemerkenswerte Fortschritte bezüglich der Empfindlichkeit und chemischen Selektivität gegenüber einer Vielzahl chemischer Spezies erzielt. Trotz der zahlreichen Verbesserungen sind aber noch einige wichtige Probleme zu lösen, bevor Kohlenstoff‐Nanoröhren mit den modernsten Feststoff‐Sensormaterialien konkurrieren können. Die Entwicklung von Sensoren auf der Basis von Kohlenstoff‐Nanoröhren befindet sich zwar noch im Anfangsstadium, aber bei weiteren Fortschritten erscheint ihre Integration in kommerziell tragfähige Sensoren, die sich dann durch eine konkurrenzlose Empfindlichkeit und außerordentlich kleine Abmessungen auszeichnen werden, möglich.
Solvent‐Ligated Copper(II) Complexes for the Homopolymerization of 2‐Methylpropene
Authors: Li Yang , Voon Lih Ting , Yeong Hui Yee , Hijazi Ahmed K. , Radhakrishnan Narayanan , Köhler Klaus , Voit Brigitte , Nuyken Oskar , Kühn Fritz E. 
Published: July 2008

AbstractCopper(II) complexes with weakly coordinating counter anions can be utilized as highly efficient catalysts for the synthesis of poly(2‐methylpropene) (“polyisobutene”) with a high content of terminal double bonds. These copper(II) compounds are significantly more active than the manganese(II) complexes described previously, can be applied in chlorine‐free solvents such as toluene, are easily accessible, and can be handled at room temperature and in laboratory atmospheres for brief periods, but they are sensitive to excess water, thereby losing their catalytic activity. Replacing the acetonitrile ligands by benzonitrile ligands improves the solubility and catalytic activity in nonpolar and nonchlorinated solvents. However, the benzonitrile copper(II) compounds have lower thermal stability than their acetonitrile congeners.
Mono‐ and Diprotonation of the Superbasic Bisguanidine 1,2‐Bis(N,N,N′,N′‐tetramethylguanidino)benzene (btmgb) and PtII and PtIV Complexes of Chelating Bisguanidines and Guanidinates
Authors: Peters Anastasia , Wild Ute , Hübner Olaf , Kaifer Elisabeth , Himmel Hans‐Jörg 
Published: July 2008

AbstractNew Pt complexes of chelating bisguanidines and guanidinate ligands were synthesized and characterized. 1,2‐Bis(N,N,N′,N′‐tetramethylguanidino)benzene (btmgb) was used as a neutral chelating bisguanidine ligand, and 1,3,4,6,7,8‐hexahydro‐2H‐pyrimido[1,2‐a]pyrimidinate (hpp−) as a guanidinate ligand. The salts [btmgbH]+[HOB(C6F5)3]− and [btmgbH2]Cl2 and the complexes [(btmgb)PtCl2], [(btmgb)PtCl(dmso)]+[PtCl3(dmso)]−, and [(btmgb)PtCl(dmso)]+[Cl−] were synthesized and characterized. In the [btmgbH]+ cation the proton is bound to only one N atom. In the other complexes, both imine N atoms are coordinated to the PtII, thus adopting a η2‐coordinational mode. The hpp− anion, which usually prefers a bridging binding mode in dinuclear complexes, is η2‐coordinated in the PtIV complex [(η2‐hpp)(hppH)PtCl2{N(H)C(O)CH3}], which is formed (in low yield) by reaction between cis‐[(hppH)2PtCl2] and H2O2 in CH3CN.
Experimental Measurement of Carbohydrate–Aromatic Stacking in Water by Using a Dangling‐Ended DNA Model System
Authors: Morales Juan C. , Reina José J. , Díaz Irene , Aviñó Anna , Nieto Pedro M. , Eritja Ramón 
Published: July 2008

AbstractProtein–carbohydrate recognition is of fundamental importance for a large number of biological processes; carbohydrate–aromatic stacking is a widespread, but poorly understood, structural motif in this recognition. We describe, for the first time, the measurement of carbohydrate–aromatic interactions from their contribution to the stability of a dangling‐ended DNA model system. We observe clear differences in the energetics of the interactions of several monosaccharides with a benzene moiety depending on the number of hydroxy groups, the stereochemistry, and the presence of a methyl group in the pyranose ring. A fucose–benzene pair is the most stabilizing of the studied series (−0.4 Kcal mol−1) and this interaction can be placed in the same range as other more studied interactions with aromatic residues of proteins, such as Phe–Phe, Phe–Met, or Phe–His. The noncovalent forces involved seem to be dispersion forces and nonconventional hydrogen bonds, whereas hydrophobic effects do not seem to drive the interaction.
The Basicity of Unsaturated Hydrocarbons as Probed by Hydrogen‐Bond‐Acceptor Ability: Bifurcated NH+⋅⋅⋅π Hydrogen Bonding
Authors: Stoyanov Evgenii S. , Stoyanova Irina V. , Reed Christopher A. 
Published: July 2008

AbstractThe competitive substitution of the anion (A−) in contact ion pairs of the type [Oct3NH+]B(C6F5)4− by unsaturated hydrocarbons (L) in accordance with the equilibrium Oct3NH+⋅⋅⋅A− + nL ⇄ [Oct3NH+⋅⋅⋅Ln]A− has been studied in CCl4. On the basis of equilibrium constants, K, and shifts of νNH to low frequency, it has been established that complexed Oct3NH+⋅⋅⋅Ln cations with n=1 and 2 are formed and have unidentate and bifurcated NH+⋅⋅⋅π hydrogen bonds, respectively. Bifurcated hydrogen bonds to unsaturated hydrocarbons have not been observed previously. The unsaturated hydrocarbons studied include benzene and methylbenzenes, fused‐ring aromatics, alkenes, conjugated dienes, and alkynes. From the magnitude of the redshifts in the NH stretching frequencies, ΔνNH, a new scale for ranking the π basicity of unsaturated hydrocarbons is proposed: fused‐ring aromatics≤benzene<toluene<xylene<mesitylene<durene<conjugated dienes≈1‐alkynes<pentamethylbenzene<hexamethylbenzene<internal alkynes≈cycloalkenes<1‐methylcycloalkenes. This scale is relevant to the discussion of π complexes for incipient protonation reactions and to understanding NH+⋅⋅⋅π hydrogen bonding in proteins and molecular crystals.
Ruthenium‐Based Olefin Metathesis Catalysts Coordinated with Unsymmetrical N‐Heterocyclic Carbene Ligands: Synthesis, Structure, and Catalytic Activity
Authors: Vougioukalakis Georgios C. , Grubbs Robert H. 
Published: July 2008

AbstractA series of ruthenium‐based olefin metathesis catalysts coordinated with unsymmetrical N‐heterocyclic carbene (NHC) ligands has been prepared and fully characterized. These complexes are readily accessible in one or two steps from commercially available [(PCy3)2Cl2RuCHPh]. All of the complexes reported herein promote the ring‐closing of diethyldiallyl and diethylallylmethallyl malonate, the ring‐opening metathesis polymerization of 1,5‐cyclooctadiene, and the cross metathesis of allyl benzene with cis‐1,4‐diacetoxy‐2‐butene, in some cases surpassing in efficiency the existing second‐generation catalysts. Especially in the cross metathesis of allyl benzene with cis‐1,4‐diacetoxy‐2‐butene, all new catalysts demonstrate similar or higher activity than the second‐generation ruthenium catalysts and, most importantly, afford improved E/Z ratios of the desired cross‐product at conversion above 60 %. The influence of the unsymmetrical NHC ligands on the initiation rate and the activation parameters for the irreversible reaction of these ruthenium complexes with butyl vinyl ether were also studied. Finally, the synthesis of the related chlorodicarbonyl(carbene) rhodium(I) complexes allowed for the study of the electronic properties of the new unsymmetrical NHC ligands that are discussed in detail.
Synthesis of 4,5‐Dihydroisoxazoles by Condensation of Primary Nitro Compounds with Alkenes by Using a Copper/Base Catalytic System
Authors: Cecchi Luca , De Sarlo Francesco , Machetti Fabrizio 
Published: July 2008

AbstractA new procedure for the synthesis of 4.5‐dihydroisoxazoles by condensation of primary nitro compounds with olefins by using a copper/base catalytic system is described. The catalytic effect of copper(II) salts is evidenced by comparison of the reaction rates. Thus, activated nitro compounds react faster than with organic catalysis by tertiary amines, whereas nitroalkanes, unable to condense with dipolarophiles in the presence of the base alone, undergo the reaction on addition of a copper(II) catalyst. The observed occurrence of induction periods in most reactions is ascribed to an equilibrium preceding the rate‐determining step, and gives a hint as to the proposed reaction mechanism. The results indicate that this method might be of practical and general utility for synthetic practice.
Prognostic factors for functional outcome and survival after reirradiation for in‐field recurrences of metastatic spinal cord compression
Authors: Rades Dirk , Rudat Volker , Veninga Theo , Stalpers Lukas J. A. , Hoskin Peter J. , Schild Steven E. 
Published: July 2008

AbstractBACKGROUND.The purpose of the current study was to retrospectively investigate clinical outcome and potential prognostic factors after reirradiation (Re‐RT) for in‐field recurrence of metastatic spinal cord compression (MSCC).METHODS.Re‐RT with 1 × 8 Gy (n = 48), 5 × 3 Gy (n = 29), 5 × 4 Gy (n = 30), 7 × 3 Gy (n = 3), 10‐12 × 2 Gy (n = 11), or 17 × 1.8 Gy (n = 3) was administered to 124 patients. Cumulative biologically effective dose (BED) (first course of RT plus re‐RT) ranged from 77.5 Gy2 to 142.6 Gy2, and was ≤120 Gy2 in 114 (92%) patients. Twelve potential prognostic factors were investigated for associations with motor function and survival.RESULTS.Motor function improved in 45 (36%) patients, was stable in another 62 (50%) patients, and deteriorated in 17 (14%) patients. Upon multivariate analyses, the effect of Re‐RT on motor function was significantly associated with the effect of the first course of RT (P = .048), Eastern Cooperative Oncology Group (ECOG) performance status (P = .020), time to development of motor deficits before Re‐RT (P = .002), and visceral metastases (P < .001). Survival was associated with ECOG performance status (P < .001), ambulatory status before Re‐RT (P < .001), time to development of motor deficits (P = .018), and visceral metastases (P <.001). Re‐RT dose schedule or cumulative BED had no significant impact on functional outcome or survival. Acute toxicity was mild, and late toxicity, such as radiation myelopathy, was not observed.CONCLUSIONS.Given the limitations of a retrospective study and the relatively short follow up after Re‐RT, spinal reirradiation appeared to be effective and safe when the cumulative BED is ≤120 Gy2. Motor function after Re‐RT was associated with the effect of first irradiation, performance status, time to development of motor deficits, and visceral metastases, whereas the Re‐RT schedule had no significant impact. Cancer 2008. © 2008 American Cancer Society.
Segmentation and analysis of the three‐dimensional redistribution of nuclear components in human mesenchymal stem cells
Authors: Vermolen Bart J. , Garini Yuval , Young Ian T. , Dirks Roeland W. , Raz Vered 
Published: July 2008

AbstractTo better understand the impact of changes in nuclear architecture on nuclear functions, it is essential to quantitatively elucidate the three‐dimensional organization of nuclear components using image processing tools. We have developed a novel image segmentation method, which involves a contrast enhancement and a subsequent thresholding step. In addition, we have developed a new segmentation method of the nuclear volume using the fluorescent background signal of a probe. After segmentation of the nucleus, a first‐order normalization is performed on the signal positions of the component of interest to correct for the shape of the nucleus. This method allowed us to compare various signal positions within a single nucleus, and also on pooled data obtained from multiple nuclei, which may vary in size and shape. The algorithms have been tested by analyzing the spatial localization of nuclear bodies in relation to the nuclear center. Next, we used this new tool to study the change in the spatial distribution of nuclear components in cells before and after caspase‐8 activation, which leads to cell death. Compared to the morphological TopHat method, this method gives similar but significantly faster results. A clear shift in the radial distribution of centromeres has been found, while the radial distribution of telomeres was changed much less. In addition, we have used this new tool to follow changes in the spatial distribution of two nuclear components in the same nucleus during activation of apoptosis. We show that after caspase‐8 activation, when centromeres shift to a peripheral localization, the spatial distribution of PML‐NBs does not change while that of centromeres did. We propose that the use of this new image segmentation method will contribute to a better understanding of the 3D spatial organization of the cell nucleus. © 2008 International Society for Advancement of Cytometry
Analysis of clinical flow cytometric immunophenotyping data by clustering on statistical manifolds: Treating flow cytometry data as high‐dimensional objects
Authors: Finn William G. , Carter Kevin M. , Raich Raviv , Stoolman Lloyd M. , Hero Alfred O. 
Published: July 2008

AbstractBackgroundClinical flow cytometry typically involves the sequential interpretation of two‐dimensional histograms, usually culled from six or more cellular characteristics, following initial selection (gating) of cell populations based on a different subset of these characteristics. We examined the feasibility of instead treating gated n‐parameter clinical flow cytometry data as objects embedded in n‐dimensional space using principles of information geometry via a recently described method known as Fisher Information Non‐parametric Embedding (FINE).MethodsAfter initial selection of relevant cell populations through an iterative gating strategy, we converted four color (six‐parameter) clinical flow cytometry datasets into six‐dimensional probability density functions, and calculated differences among these distributions using the Kullback‐Leibler divergence (a measurement of relative distributional entropy shown to be an appropriate approximation of Fisher information distance in certain types of statistical manifolds). Neighborhood maps based on Kullback‐Leibler divergences were projected onto two dimensional displays for comparison.ResultsThese methods resulted in the effective unsupervised clustering of cases of acute lymphoblastic leukemia from cases of expansion of physiologic B‐cell precursors (hematogones) within a set of 54 patient samples.ConclusionsThe treatment of flow cytometry datasets as objects embedded in high‐dimensional space (as opposed to sequential two‐dimensional analyses) harbors the potential for use as a decision‐support tool in clinical practice or as a means for context‐based archiving and searching of clinical flow cytometry data based on high‐dimensional distribution patterns contained within stored list mode data. Additional studies will be needed to further test the effectiveness of this approach in clinical practice. © 2008 Clinical Cytometry Society
Solution‐Phase Synthesis of First‐Generation Tetraester Dendritic Branches Involving Microwave and/or Ultrasonic Irradiation
Authors: Wiesbrock Frank , Patteux Claudine , Olszewski Tomasz K. , Blanrue Amélie , Heropoulos Georgios A. , Steele Barry R. , Micha‐Screttas Maria , Calogeropoulou Theodora 
Published: July 2008

AbstractTrifunctionalized aromatic cores were selectively protected to obtain precursors for bidirectional dendritic unit growth through stepwise divergent syntheses. The synthesis of first‐generation dendrimer building blocks was performed by nucleophilic substitution of bromomethyl‐substituted aromatic cores with diethyl malonate anions in the presence of carbonate in halogen‐free solvents. The screening of the reaction parameters revealed the optimum conditions for small‐ and larger‐scale synthesis: these require microwave or ultrasonic irradiation to achieve yields around 70 % in reaction times as short as 15 min. As a result of the heterogeneity of the reaction mixtures, efficient stirring was important to suppress byproduct formation.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Capillary electrophoresis‐based immunoassays: Principles and quantitative applications
Authors: Moser Annette C. , Hage David S. 
Published: July 2008

AbstractThe use of CE as a tool to conduct immunoassays has been an area of increasing interest over the last decade. This approach combines the efficiency, small sample requirements, and relatively high speed of CE with the selectivity of antibodies as binding agents. This review examines the various assay formats and detection modes that have been reported for these assays, along with some representative applications. Most CE immunoassays in the past have employed homogeneous methods in which the sample and reagents are allowed to react in solution. These homogeneous methods have been conducted as both competitive binding immunoassays and as noncompetitive binding immunoassays. Fluorescent labels are most commonly used for detection in these assays, but enzyme labels have also been utilized for such work. Some additional work has been performed in CE immunoassays with heterogeneous methods in which either antibodies or an analog of the analyte is immobilized to a solid support. These heterogeneous methods can be used for the selective isolation of analytes prior to their separation by CE or to remove a given species from a sample/reagent mixture prior to analysis by CE. These CE immunoassays can be used with a variety of detection modes, such as fluorescence, UV/Vis absorbance, chemiluminescence, electrochemical measurements, MS, and surface plasmon resonance.
Development of aptamer‐based affinity assays using temperature gradient focusing: Minimization of the limit of detection
Authors: Munson Matthew S. , Meacham J. Mark , Ross David , Locascio Laurie E. 
Published: July 2008

AbstractA method is described for an aptamer‐based affinity assay using a combination of two nonconventional techniques, temperature gradient focusing (TGF) and field‐amplified continuous sample injection TGF (FACSI‐TGF), with fluorescence detection. Human immunodeficiency virus reverse transcriptase (HIVRT) is used as the protein target for the assay. The TGF and FACSI‐TGF assays are compared to similar results obtained with conventional CE. A range of starting aptamer concentrations are used to determine the optimal LOD for human immunodeficiency virus reverse transcriptase (HIVRT) using each approach. The results indicate that the LODs for HIVRT obtained with TGF and FACSI‐TGF are comparable to or even lower than the LODs obtained with conventional CE in spite of the inferior detector used for the TGF and FACSI‐TGF assays (arc lamp and low‐cost CCD for TGF versus LIF with PMT for CE). It is hypothesized that this is due to the greater reproducibility of the TGF and FACSI‐TGF techniques since they do not employ a defined sample injection. The lowest LOD achieved with the new aptamer assay approach is more than an order of magnitude lower than that reported for a similar CE‐based aptamer assay for the same target.
Aging of cerebral white matter: a review of MRI findings
Authors: Gunning‐Dixon Faith M. , Brickman Adam M. , Cheng Janice C. , Alexopoulos George S. 
Published: July 2008

AbstractBackgroundCerebral aging is a complex and heterogeneous process that is associated with a high degree of inter‐individual variability. Structural magnetic resonance imaging (MRI) can be used to identify and quantify non‐disease‐related aging of the cerebral white matter.MethodsThe present article reviews the findings from several MRI techniques, including morphometric approaches, study of white matter hyperintensities, diffusion tensor imaging, and magnetization transfer imaging, that have been used to examine aging of the cerebral white matter. Furthermore, the relationship of MRI indices of white matter integrity to age‐related cognitive declines is reported.ResultsA general pattern of age‐related preservation and decline emerges indicating that the prefrontal white matter is most susceptible to the influence of age. Studies that combine MRI with cognitive measures suggest that such age‐related reductions in white matter integrity may produce a disconnection state that underlies some of the age‐related performance declines in age‐sensitive cognitive domains.ConclusionsWhite matter aging may contribute to a disconnection state that is associated with declines in episodic memory, executive functions, and information processing speed. Copyright © 2008 John Wiley & Sons, Ltd.
Prostaglandin E2 pathway in head and neck squamous cell carcinoma
Authors: Camacho Mercedes , León Xavier , Fernández‐Figueras María‐Teresa , Quer Miquel , Vila Luis 
Published: July 2008

AbstractBackground.Prostaglandin E2 (PGE2) is involved in malignant growth. The objective was to study the PGE2 pathway in head and neck squamous cell carcinoma (HNSCC) patients.Methods.Expression of cyclooxygenase (COX) and PGE‐synthase isoenzymes, and PGE‐receptors was determined in biopsies from 83 patients with HNSCC by real‐time reverse transcriptase–polymerase chain reaction (RT‐PCR).Results.Expression of COX‐2 and cytosolic‐PGE‐synthase was significantly increased, about 4‐fold and 2.5‐fold, respectively, in tumors versus paired nontumoral mucosa (n = 34). EP‐1 was the only PGE‐receptor significantly overexpressed in tumor samples. Expression of COX‐1 correlated with mPGES‐2 and COX‐2 correlated with mPGES‐1 (n = 83).Conclusions.COX‐2, functionally coordinated with mPGES‐1, is likely to be the limiting enzyme in PGE2 biosynthesis in HNSCC. The biological meaning of cPGES/p23 overexpression in HNSCC is not yet clear. Our results support the notion that mPGES‐1, cPGES, and EP‐1 could be the targets for the development of specific PGE2‐modifier drugs for HNSCC treatment that could avoid negative side effects of COX‐2 selective inhibitors. © 2008 Wiley Periodicals, Inc. Head Neck 2008