bluuebunny/crossref_metadata_2025_split huggingface dataset:
Illuminating the Mechanism of the Borane‐Catalyzed Hydrosilylation of Imines with Both an Axially Chiral Borane and Silane
Authors: Mewald Marius , Oestreich Martin 
Published: September 2012

AbstractThe reduction of CO groups with silanes catalyzed by electron‐deficient boranes follows a counterintuitive mechanism in which the SiH bond is activated by the boron Lewis acid prior to nucleophilic attack of the carbonyl oxygen atom at the silicon atom. The borohydride thus formed is the actual reductant. These steps were elucidated by using a silicon‐stereogenic silane, but applying the same technique to the related reduction of CN groups was inconclusive due to racemization of the silicon atom. The present investigation now proves by the deliberate combination of our axially chiral borane catalyst and axially chiral silane reagents (in both enantiomeric forms) that the mechanisms of these hydrosilylations are essentially identical. Unmistakable stereochemical outcomes for the borane/silane pairs show that both participate in the enantioselectivity‐determining hydride‐transfer step. These experiments became possible after the discovery that our axially chiral C6F5‐substituted borane induces appreciable levels of enantioinduction in the imine hydrosilylation.
ChemInform Abstract: Unique Catalysis of Gold Nanoparticles in the Chemoselective Hydrogenolysis with H2: Cooperative Effect Between Small Gold Nanoparticles and a Basic Support.
Authors: Noujima Akifumi , Mitsudome Takato , Mizugaki Tomoo , Jitsukawa Koichiro , Kaneda Kiyotomi 
Published: September 2012

AbstractGold nanoparticles on hydrotalcite act as a heterogeneous catalyst for the chemoselective hydrogenolysis of various allylic carbonates (I), (IV) to the corresponding terminal alkenes (II) without C—C double bond reduction.
ChemInform Abstract: Csp2—Csp2 Bond Formation via Lewis Acid/Ammonium Salt Cocatalyzed Tandem Addition and Oxidative Dehydrogenation Strategy: Alkenylation of Indoles with α,β‐Unsaturated Ketones.
Authors: Xiang Shi‐Kai , Wu Guolin , Zhang Bo , Cui Yuxin , Jiao Ning 
Published: September 2012

AbstractAn alkenylation of indoles at C‐3 is developed through tandem addition and oxidative dehydration.
ChemInform Abstract: Novel Synthetic Methodologies. Part 10. A New Iodine‐Catalyzed Regioselective Synthesis of Xanthene Synthons.
Authors: Sashidhara Koneni V. , Kumar Abdhesh , Dodda Ranga Prasad , Kumar Bikash 
Published: September 2012

AbstractThe synthesis of p‐condensed xanthenes (III) is achieved by iodine catalyzed condensation of dialdehydes (I) with naphthols (II) in the presence of I2.
ChemInform Abstract: Cobalt‐Catalyzed Asymmetric Addition of Silylacetylenes to Oxa‐ and Azabenzonorbornadienes.
Authors: Sawano Takahiro , Ou Keiyu , Nishimura Takahiro , Hayashi Tamio 
Published: September 2012

AbstractNoteworthy, alkynes, such as phenylacetylene or octyne fail to give the title reaction.
Access to Enantiomerically Pure cis‐ and trans‐β‐Phenylproline by High‐Performance Liquid Chromatography Resolution
Authors: Fatás Paola , Gil Ana M. , Calaza M. Isabel , Jiménez Ana I. , Cativiela Carlos 
Published: September 2012

ABSTRACTThe preparation of all four stereoisomers of the proline analog that bears a phenyl group attached to the β carbon either cis or trans to the carboxylic acid (cis‐ and trans‐β‐phenylproline, respectively) has been addressed. The methodology developed allows access to multigram quantities of the target amino acids in enantiomerically pure form and suitably protected for use in peptide synthesis. Racemic precursors of cis‐β‐phenylproline and trans‐β‐phenylproline were prepared from easily available starting materials and subjected to high‐performance liquid chromatography enantioseparation. Semipreparative columns (250 × 20 mm) containing chiral stationary phases based on amylose (Chiralpak IA) (Daicel‐Chiral Technologies Europe, Illkirch, France) or cellulose (Chiralpak IC) were used respectively for the resolution of the cis‐ and trans‐β‐phenylproline precursors. Chirality, 24:1082‐1091, 2012. © 2012 Wiley Periodicals, Inc.
A universal nanoparticle cell secretion capture assay
Authors: Fitzgerald Wendy , Grivel Jean‐Charles 
Published: September 2012

AbstractSecreted proteins play an important role in intercellular interactions, especially between cells of the immune system. Currently, there is no universal assay that allows a simple noninvasive identification and isolation of cells based on their secretion of various products. We have developed such a method. Our method is based on the targeting, to the cell surface, of heterofunctional nanoparticles coupled to a cell surface‐specific antibody and to a secreted protein‐specific antibody, which captures the secreted protein on the surface of the producing cell. Importantly, this method does not compromise cellviability and is compatible with further culture and expansion of the secreting cells. Published 2012 Wiley‐Periodicals, Inc.
Evaluation of calcineurin/NFAT inhibitor selectivity in primary human Th cells using bar‐coding and phospho‐flow cytometry
Authors: Frischbutter Stefan , Schultheis Katherine , Pätzel Michael , Radbruch Andreas , Baumgrass Ria 
Published: September 2012

AbstractSmall molecular inhibitors are excellent tools for manipulating cell reactions. They are widely used in scientific research to study molecular mechanisms of cells under physiological and pathophysiological conditions as well as in clinical applications to treat patients. However, their selectivity is often not well known. Moreover, it can vary according to cell types and the analysis methods used. Therefore, it is usually not possible to make comparisons between the data presented in the literature. Here we analyzed the selectivity of five chosen inhibitors of calcineurin/NFAT activation under the same conditions. Using a combination of fluorescent cell barcoding and phospho‐specific flow cytometry we studied the inhibition of activation of NF‐κBp65 and MAPK pathways in stimulated primary human Th cells. This semi‐high throughput approach enabled us to demonstrate that (i) CsA and NCI3 are around 5 to 10‐ and 20‐fold less potent, respectively, at inhibiting phosphorylation of NF‐κBp65 and p38 than activation of NFAT, (ii) AM404 is at least 15‐fold selective for NFAT but already toxic at concentrations above 40 μM, (iii) INCA6 is not selective at all, and (iv) BTP1 is at least 100‐fold selective for inhibition of NFAT activation relative to NF‐κBp65, p38 and ERK1/2 phosphorylation. Altogether, our results not only show the applicability of a semi‐high throughput inhibitor test system but also that BTP1 is the most selective inhibitor of calcineurin/NFAT activation among the studied inhibitors under the used conditions.
Modular Synthesis of Planar‐Chiral para‐Substituted Paracyclophanes by Double Suzuki Coupling
Authors: Cakici Murat , Bräse Stefan 
Published: September 2012

AbstractThe first synthesis of enantiomerically pure 4,7‐paracyclophane ditriflate starting from a quinone was reported. Using this molecule, mono‐ or dicoupling with boronic acids delivered enantiomerically pure arylparacyclophanes.
Synthesis and Aggregation Properties of Polycationic Perylenetetracarboxylic Acid Diimides
Authors: Schönamsgruber Jörg , Schade Boris , Kirschbaum Rolf , Li Jing , Bauer Walter , Böttcher Christoph , Drewello Thomas , Hirsch Andreas 
Published: September 2012

AbstractThe synthesis and structural characterization of a first family of dendronized polycationic perylenetetracarboxylic acid diimides (PDIs) 7, 8, and 10 is reported. They were obtained by amide coupling reactions of pyridinium salt head groups with terminal carboxylic groups of Newkome‐dendron‐type functionalized PDIs. Resulting pyridinium‐terminated PDIs 7, 8, and 10 are highly water‐soluble, independent of the pH value. This is due to 6, 18, and 9 permanent positive charges, respectively. PDIs 7 containing the smaller first‐generation dendrons exhibit a pronounced aggregation behavior in water. This was studied by absorption and fluorescence spectroscopy, by pulsed‐gradient spin‐echo (PGSE, DOSY) NMR measurements, and by cryo‐transmission electron microscopy (cryo‐TEM). The counterparts containing the bulkier second‐generation dendrons hamper aggregation, and as a consequence intermolecular π–π stacking interactions between the perylene cores is suppressed.
BaTiO3‐based nanolayers and nanotubes: First‐principles calculations
Authors: Evarestov Robert A. , Bandura Andrei V. , Kuruch Dmitrii D. 
Published: September 2012

AbstractThe first‐principles calculations using hybrid exchange‐correlation functional and localized atomic basis set are performed for BaTiO3 (BTO) nanolayers and nanotubes (NTs) with the structure optimization. Both the cubic and the ferroelectric BTO phases are used for the nanolayers and NTs modeling. It follows from the calculations that nanolayers of the different ferroelectric BTO phases have the practically identical surface energies and are more stable than nanolayers of the cubic phase. Thin nanosheets composed of three or more dense layers of (0 1 0) and (0 1
$\bar 1$) faces preserve the ferroelectric displacements inherent to the initial bulk phase. The structure and stability of BTO single‐wall NTs depends on the original bulk crystal phase and a wall thickness. The majority of the considered NTs with the low formation and strain energies has the mirror plane perpendicular to the tube axis and therefore cannot exhibit ferroelectricity. The NTs folded from (0 1
$\bar 1$) layers may show antiferroelectric arrangement of TiO bonds. Comparison of stability of the BTO‐based and SrTiO3‐based NTs shows that the former are more stable than the latter. © 2012 Wiley Periodicals, Inc.
Correlation of sonographic features of invasive ductal mammary carcinoma with age, tumor grade, and hormone‐receptor status
Authors: Aho Michael , Irshad Abid , Ackerman Susan J. , Lewis Madelene , Leddy Rebecca , Pope Thomas L. , Campbell Amy S. , Cluver Abbie , Wolf Bethany J. , Cunningham Joan E. 
Published: September 2012

AbstractPurpose.To determine whether presenting sonographic features of invasive ductal carcinomas (IDC) are associated with patient age, tumor histologic grade, and hormonal receptor status.Methods.Sonographic features of 101 consecutive cases of IDC seen at ultrasound were retrospectively assessed based on the BI‐RADS criteria of posterior acoustic appearance, tumor margins, and echogenicity. Associations between sonographic features and tumor characteristics were statistically evaluated with attention to patient age.Results.IDC with shadowing compared with unchanged posterior acoustic appearance were significantly more likely to be of low histologic grade (Odds Ratio [OR] = 5.00; p < 0.05) and estrogen receptor (ER) ‐positive (OR = 10.00; p < 0.05). Conversely, posterior enhancement was associated with ER‐negative status (OR = 4.45; p < 0.01), particularly among patients younger than 60 years of age (OR = 5.36, p < 0.05). Circumscribed tumors were more often high grade, particularly among older women (p < 0.01), and hormone receptor‐‐negative regardless of age group. Among older women, tumors with mixed echogenicity tended to be high grade and progesterone receptor‐‐negative (p values < 0.05). Noncircumscribed borders were observed for all tumors with posterior shadowing, and 97% of such tumors were also ER positive.Conclusions.Sonographic features were significantly associated with tumor grade and hormone receptor status, with some differences based on patient age. Specifically, the presence of posterior shadowing was associated with lower histologic grade and ER‐positive status, especially in older patients. In contrast, we found that posterior acoustic enhancement was more commonly associated with ER‐negative status, especially in younger patients. © 2012 Wiley Periodicals, Inc. J Clin Ultrasound 2013
Modified cine inversion recovery pulse sequence for the quantification of myocardial T1 and gadolinium partition coefficient
Authors: Milanesi Matteo , Barison Andrea , Positano Vincenzo , Masci Pier Giorgio , De Marchi Daniele , Marinelli Luca , Hardy Christopher J. , Foo Thomas K. , Landini Luigi , Lombardi Massimo 
Published: September 2012

AbstractPurpose:To optimize and validate a modified cine inversion recovery sequence (MCine‐IR) for myocardial T1 quantification and gadolinium partition coefficient (λGd) estimation at 1.5 T.Materials and Methods:The original version of the cine inversion recovery sequence was modified to allow fully transverse magnetization recovery between two successive inversion pulses. Sixty heart phases were acquired from a number of heart cycles determined on a patient heart rate basis. Phantom studies were carried out to find the optimal effective TR for myocardial and blood pool T1 quantifications in pre‐ and postcontrast studies. Four patients with myocardial infarct (MI) and 22 dilated cardiomyopathy (DCM) were investigated, as well as 11 healthy subjects used as controls.Results:Effective TR was identified to be 5000 msec and 2000 msec, respectively, for pre‐ and postcontrast studies. A longer precontrast (948 ± 102 msec) and shorter postcontrast (348 ± 27 msec) T1 in ischemic patients relative to DCM (815 ± 98 msec, P = 0.03 and 409 ± 42 msec, P = 0.001) were noted in delayed enhancement (DE) areas. In MI patients λGd resulted higher than in DCM in DE areas (609 ± 167 vs. 422 ± 52, P = 0.01) but lower in segments not exhibiting DE (355 ± 100 vs. 398 ± 54, P = 0.02).Conclusion:It was feasible to measure T1 and λGd with MCine‐IR and the results were in good agreement with the literature. J. Magn. Reson. Imaging 2013;37:109–118. © 2012 Wiley Periodicals, Inc.
Time‐resolved MR venography of the pulmonary veins precatheter‐based ablation for atrial fibrillation
Authors: Schonberger Michael , Usman Asad , Galizia Maurizio , Popescu Andrada , Collins Jeremy , Carr James C. 
Published: September 2012

AbstractPurpose:To evaluate time‐resolved magnetic resonance angiography (TR‐MRA) of the pulmonary venous circulation using the time‐resolved angiography with interleaved stochastic trajectories (TWIST) method and compare it with the more commonly used conventional contrast‐enhanced magnetic resonance angiography (CE‐MRA) approach in atrial fibrillation patients referred for preablation pulmonary vein mapping.Materials and Methods:This study was approved by the Institutional Review Board. Twenty‐six patients (15 males; age 59.6 ± 12.7 years) referred for preablation pulmonary vein mapping underwent both conventional CE‐MRA and TR‐MRA with TWIST. Imaging was performed on a 1.5 T (Magnetom Avanto, Siemens Healthcare, Erlangen, Germany) MRI scanner. Source partition and maximum intensity projection (MIP) images were evaluated retrospectively. For quantitative analysis, pulmonary vein ostium orthogonal dimensions were measured using double oblique multiplanar reformatting. The results were analyzed using paired t‐tests, Lin's concordance correlation coefficient, and Bland–Altman plots. For qualitative analysis, both source partition images and MIP images were assessed by two observers (A.P. and M.G.). The presence of common ostiums or accessory veins was recorded and analyzed using unweighted Cohen's kappa. Pulmonary vein conspicuity was scored on a scale of 1–4 (1 = poor, 2 = fair, 3 = good, 4 = excellent) and analyzed using paired t‐tests, intraclass correlation coefficients, and quadratic weighted kappa statistics.Results:Orthogonal venous diameters were comparable for both TR‐MRA and conventional CE‐MRA (1.34 ± 0.37 vs. 1.38 cm ± 0.36, respectively). Results of paired t‐tests, Lin's concordance correlation coefficient, and Bland–Altman analysis revealed relatively close comparison between methods. The magnitude of the mean difference for any of the statistical comparisons did not exceed 0.10 cm. The visualization of variant pulmonary vein anatomy was very similar for both techniques. Agreement between techniques was determined to be “good” to “very good” (κ = 0.78–0.85). Conspicuity scores for each pulmonary vein were also very close. Paired t‐tests, intraclass correlation coefficients, and quadratic weighted kappa statistics all revealed strong agreement between methods.Conclusion:TR‐MRA using TWIST produces comparable anatomic images and pulmonary venous dimensions to the more widely used CE‐MRA technique. Additionally, the TWIST technique improves arterio‐venous separation, does not need exact bolus timing, requires less gadolinium, and gives additional information on vein perfusion. J. Magn. Reson. Imaging 2013;37:127–137. © 2012 Wiley Periodicals, Inc.
Contribution of bone marrow‐derived endothelial progenitor cells to neovascularization and astrogliosis following spinal cord injury
Authors: Kamei Naosuke , Kwon Sang‐Mo , Kawamoto Atsuhiko , Ii Masaaki , Ishikawa Masakazu , Ochi Mitsuo , Asahara Takayuki 
Published: September 2012

AbstractSpinal cord injury causes initial mechanical damage, followed by ischemia‐induced, secondary degeneration, worsening the tissue damage. Although endothelial progenitor cells (EPCs) have been reported to play an important role for pathophysiological neovascularization in various ischemic tissues, the EPC kinetics following spinal cord injury have never been elucidated. In this study, we therefore assessed the in vivo kinetics of bone marrow‐derived EPCs by EPC colony‐forming assay and bone marrow transplantation from Tie2/lacZ transgenic mice into wild‐type mice with spinal cord injury. The number of circulating mononuclear cells and EPC colonies formed by the mononuclear cells peaked at day 3 postspinal cord injury. Bone marrow transplantation study revealed that bone marrow‐derived EPCs recruited into the injured spinal cord markedly increased at day 7, when neovascularization and astrogliosis drastically occurred in parallel with axon growth in the damaged tissue. To elucidate further the contribution of EPCs to recovery after spinal cord injury, exogenous EPCs were systemically infused immediately after the injury. The administered EPCs were incorporated into the injured spinal cord and accelerated neovascularization and astrogliosis. These findings suggest that bone marrow‐derived EPCs may contribute to the tissue repair by augmenting neovascularization and astrogliosis following spinal cord injury. © 2012 Wiley Periodicals, Inc.
β‐Amyloid induced effects on cholinergic, serotonergic, and dopaminergic neurons is differentially counteracted by anti‐inflammatory drugs
Authors: Hochstrasser Tanja , Hohsfield Lindsay A. , Sperner‐Unterweger Barbara , Humpel Christian 
Published: September 2012

Abstractβ‐Amyloid (Aβ) is a small peptide that plays a potent role in synaptic plasticity as well as forms amyloid plaques in Alzheimer's disease (AD). Recent studies suggest that Aβ deposition is deleterious not only in AD, but also in Parkinson's disease (PD) and depression. This Aβ effect is associated with inflammatory processes. However, further evaluation is needed to understand how Aβ and inflammation interact and contribute to the regulation of the cholinergic, serotonergic, and dopaminergic neuronal populations. The aim of the present study was to investigate the effects of Aβ1–42 on cholinergic neurons of the nucleus basalis of Meynert (which degenerate in AD), on serotonergic neurons of the dorsal raphe nucleus (which play a role in depression), and on dopaminergic neurons of the ventral mesencephalon (which degenerate in PD) in rat organotypic brain slices. Furthermore, we investigated whether anti‐inflammatory drugs (celecoxib, citalopram, cyclooxygenase‐2 inhibitor, ibuprofen, indomethacin, piclamilast) modulate or counteract Aβ‐induced effects. Two‐week‐old organotypic brain slices of the nucleus basalis of Meynert, dorsal raphe nucleus, and ventral mesencephalon were incubated with 50 ng/ml Aβ1–42 with or without anti‐inflammatory agents for 3 days. Our results reveal that Aβ significantly decreased the number of choline acetyltransferase‐positive cholinergic, tryptophan hydroxylase‐positive serotonergic, and tyrosine hydroxylase‐positive dopaminergic neurons and that anti‐inflammatory drugs partially counteracted the Aβ‐induced neuronal decline. This decline was not due to apoptotic processes (as evaluated by TUNEL, propidium iodide, caspase), oxidative stress (as measured by nitrite, catalase, or superoxide dismutase‐2), or inflammation, but was most likely caused by a downregulation of these key enzymes. © 2012 Wiley Periodicals, Inc.
Photoresponsive Azopolyester–PMMA Block Copolymers Obtained by Combination of ATRP, Polycondensation, and “Click” Chemistry
Authors: Berges Cristina , Javakhishvili Irakli , Hvilsted Søren , Sánchez Carlos , Alcalá Rafael 
Published: September 2012

AbstractNovel azobenzene‐containing block copolymers (BCs) with a polyester block bearing azobenzene moieties in the side chain and a poly (methyl methacrylate) (PMMA) block have been synthesized by the combination of atom transfer radical polymerization (ATRP), polycondensation, and “click” chemistry. Two azide‐terminated polyesters with different molecular weight (obtained by polycondensation) were coupled to an alkyne‐functionalized PMMA (obtained by ATRP). Blends of the BC with the highest azo content (wt%) and an azopolyester homopolymer were also prepared. All these compounds were investigated by polarized light optical microscopy (POM), differential scanning calorimetry (DSC), and transmission electron microscopy (TEM). Polarized light‐induced anisotropy was studied by birefringence and dichroism measurements.
Stabilizing branch‐and‐price for constrained tree problems
Authors: Leitner Markus , Ruthmair Mario , Raidl Günther R. 
Published: September 2012

AbstractWe consider a rather generic class of network design problems in which a set or subset of given terminal nodes must be connected to a dedicated root node by simple paths and a variety of resource and/or quality of service constraints must be respected. These extensions of the classical Steiner tree problem on a graph can be well modeled by a path formulation in which individual variables are used for all feasible paths. To solve this formulation in practice, branch‐and‐price is used. It turns out, however, that a naive implementation of column generation suffers strongly from certain degeneracies of the pricing subproblem, leading to excessive running times. After analyzing these computational problems, we propose two methods to accelerate and stabilize column generation by using alternative dual‐optimal solutions. The resulting branch‐and‐price approach is practically tested on the rooted delay‐constrained Steiner tree problem and a quota‐constrained version of it. Results indicate that the proposed methods in general speed‐up the solution process dramatically, far more than a piecewise linear stabilization to which we compare. Furthermore, our branch‐and‐price approach exhibits on most test instances a better performance than a state‐of‐the‐art branch‐and‐cut approach based on layered graphs. As the new stabilization technique utilizing alternative dual‐optimal solutions is generic in the sense that it easily adapts to the inclusion of a large variety of further constraints and different objective functions, the proposed method is highly promising for a large class of network design problems. © 2012 Wiley Periodicals, Inc. NETWORKS, 2013