bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modular Chiral Bidentate Phosphonites: Design, Synthesis, and Application in Catalytic Asymmetric Hydroformylation Reactions
Authors: Zhao Baoguo , Peng Xingao , Wang Zheng , Xia Chungu , Ding Kuiling 
Published: July 2008

AbstractA new class of C2‐symmetric chiral bidentate phosphonite ligands has been synthesized in moderate to good yields from readily available starting materials. Application of these air‐stable chiral phosphonites in the RhI‐catalyzed asymmetric hydroformylation of styrene derivatives, vinyl acetate, and allyl cyanide afforded the corresponding chiral aldehydes with high regio‐ and enantioselectivities under mild reaction conditions. The modular nature of the ligands allows fine‐tuning of the selectivities through judicious modifications of the substituents on the ligand backbone. X‐ray structural analysis of the catalyst precursor suggested that the steric hindrance caused by the protruding remote substituents of the ligands into the vicinity of the metal center might be an important factor for the enantio‐control of the reaction, whereas the sense of asymmetric induction can be rationalized on the basis of a trigonal‐bipyramidal transition state diagram.
HP‐Ca2Si5N8—A New High‐Pressure Nitridosilicate: Synthesis, Structure, Luminescence, and DFT Calculations
Authors: Römer S. Rebecca , Braun Cordula , Oeckler Oliver , Schmidt Peter J. , Kroll Peter , Schnick Wolfgang 
Published: July 2008

AbstractHP‐Ca2Si5N8was obtained by means of high‐pressure high‐temperature synthesis utilizing the multianvil technique (6 to 12 GPa, 900 to 1200 °C) starting from the ambient‐pressure phase Ca2Si5N8. HP‐Ca2Si5N8crystallizes in the orthorhombic crystal system (Pbca(no. 61),a=1058.4(2),b=965.2(2),c=1366.3(3) pm,V=1395.7(7)×106 pm3,Z=8,R1=0.1191). The HP‐Ca2Si5N8structure is built up by a three‐dimensional, highly condensed nitridosilicate framework with N[2]as well as N[3]bridging. Corrugated layers of corner‐sharing SiN4tetrahedra are interconnected by further SiN4units. The Ca2+ions are situated between these layers with coordination numbers 6+1 and 7+1, respectively. HP‐Ca2Si5N8as well as hypothetical orthorhombic o‐Ca2Si5N8(isostructural to the ambient‐pressure modifications of Sr2Si5N8and Ba2Si5N8) were studied as high‐pressure phases of Ca2Si5N8up to 100 GPa by using density functional calculations. The transition pressure into HP‐Ca2Si5N8was calculated to 1.7 GPa, whereas o‐Ca2Si5N8will not be adopted as a high‐pressure phase. Two different decomposition pathways of Ca2Si5N8(into Ca3N2and Si3N4or into CaSiN2and Si3N4) and their pressure dependence were examined. It was found that a pressure‐induced decomposition of Ca2Si5N8into CaSiN2and Si3N4is preferred and that Ca2Si5N8is no longer thermodynamically stable under pressures exceeding 15 GPa. Luminescence investigations (excitation at 365 nm) of HP‐Ca2Si5N8:Eu2+reveal a broadband emission peaking at 627 nm (FWHM=97 nm), similar to the ambient‐pressure phase Ca2Si5N8:Eu2+.
pKa‐Directed Host–Guest Assemblies: Rational Analysis of Molecular Adducts of 2,4‐Diamino‐6‐methyl‐1,3,5‐triazine with Various Aliphatic Dicarboxylic Acids
Authors: Delori Amit , Suresh Eringathodi , Pedireddi V. R. 
Published: July 2008

AbstractMolecular adducts of 2,4‐diamino‐6‐methyl‐1,3,5‐triazine (1) have been prepared with various aliphatic dicarboxylic acids. The molecular complexes (1 a–1 i) thus formed by co‐crystallizing 1 with oxalic, malonic, succinic, fumaric, acetylene dicarboxylic, glutaric, thiodiglycolic, diglycolic, and adipic acids have been found to give two types of host–guest assemblies that have voids or channels in a three‐dimensional arrangement. The different types of host–guest arrangement appear to result from differences in the acidity of the dicarboxylic acids, that is, acids with pKa<3.0 give host networks that consist of 1 and the corresponding acid with water or solvent molecules of crystallization present as guests, whereas acids with pKa>3.0 exist as guests in voids in a host network formed by 1. The former arrangement is observed in adducts 1 a, 1 b, 1 e, and 1 h and the latter arrangement is found in adducts 1 c, 1 d, 1 f, 1 g, and 1 i.
Na8[Cr4B12P8O44(OH)4][P2O7]⋅nH2O: A 3D Borophosphate Framework with Spherical Cages
Authors: Yang Tao , Sun Junliang , Li Guobao , Eriksson Lars , Zou Xiaodong , Liao Fuhui , Lin Jianhua 
Published: July 2008

AbstractA chromium borophosphate–phosphate (Na8[Cr4B12P8O44(OH)4][P2O7]⋅nH2O, 1), which has an unusual 3D framework structure, was synthesized under hydrothermal conditions. The framework consists of spherical cages composed of CrO6, PO4, BO4, and BO3 polyhedra. The cages are located at the vertices and the body center of the cubic cell and are interconnected through 12‐membered‐ring windows along the {111} direction. The actual framework structure is very complex, but the description can be simplified by using the 5‐connected fundamental building cluster [CrP5B3O24]11−. In addition, 1 represents the first borate‐rich borophosphate that contains a 3D borophosphate partial framework (${{{\hfill 3\atop \hfill \infty }}}$[B3P2O11(OH)]) in which the fundamental building unit is an oB dreier single ring (Δ4□:□<Δ2□>□). The cavities of the framework are filled with disengaged water molecules and Na+ counterions. The former can be reversibly desorbed and reabsorbed and the latter can be exchanged by Li+ ions, which results in significant shrinkages of the cell volume.
Screening Electronic Communication through ortho‐, meta‐ and para‐Substituted Linkers Separating Subphthalocyanines and C60
Authors: González‐Rodríguez David , Torres Tomás , Herranz María Ángeles , Echegoyen Luis , Carbonell Esther , Guldi Dirk M. 
Published: July 2008

AbstractWe have prepared two complementary series of SubPc–C60 (SubPc=subphthalocyanine) electron/energy donor–acceptor systems, in which the two constituents are linked through ortho‐, meta‐, or para‐substituted phenoxy spacers. In one of the series (1 a) the SubPc units bear iodine atoms, while in the other series (1 b) diphenylamino groups are linked to the SubPc macrocycles. The iodine atoms and diphenylamino groups both influence the resulting oxidation potentials of the electron‐donating SubPc. They also modulate the outcome of excited state interactions, namely, energy and/or charge transfer. In addition, we have studied the impact that the substitution pattern in the phenoxy spacer exerts onto intramolecular processes in the ground and excited states. Although some of these processes are governed by the spatial separation between both components, the different electronic coupling through ortho‐, meta‐, or para‐ connections also plays decisive roles in some cases.
The effect of interleukin 11 on thrombocytopenia associated with tyrosine kinase inhibitor therapy in patients with chronic myeloid leukemia
Authors: Aribi Ahmed , Kantarjian Hagop , Koller Charles , Thomas Deborah , Faderl Stefan , Garcia‐Manero Guillermo , Cortes Jorge 
Published: July 2008

AbstractBACKGROUND.During therapy with tyrosine kinase inhibitors (TKIs), approximately 20% to 50% of patients with chronic myeloid leukemia (CML) develop grade ≥3 thrombocytopenia leading to treatment interruptions and dose reductions. Interleukin 11 (IL‐11) reduces the incidence and the severity of thrombocytopenia in solid tumors.METHODS.The authors investigated the efficacy and safety of low‐dose IL‐11 for improving thrombocytopenia associated with TKI therapy in 14 patients with CML. The starting dose of IL‐11 was 10 μg/kg 3 times weekly, and the dose was escalated by 1 dose level every 2 weeks if the patients had no sustained platelet increase.RESULTS.The median patient age was 52 years. The median platelet count at the time IL‐11 was started was 37 × 109/L. All patients had prior TKI dose reductions. After the initiation of IL‐11, 8 of 14 patients (57%) had an increase in platelet count with a median peak platelet count of 110 × 109/L. One additional patient had no platelet increase but was able to tolerate an imatinib dose increase. Eleven patients had a decrease in the number of days of TKI therapy interruption secondary to thrombocytopenia after the initiation of IL‐11 (6% of total treatment time vs 34% of total treatment time before IL‐11). Therapy was well tolerated.CONCLUSIONS.The current results indicated that IL‐11 may correct thrombocytopenia associated with TKI therapy for patients with CML and that it has a favorable toxicity profile. Cancer 2008. © 2008 American Cancer Society.
Hydrogen Generation at Ambient Conditions: Application in Fuel Cells
Authors: Boddien Albert , Loges Björn , Junge Henrik , Beller Matthias 
Published: July 2008

AbstractThe efficient generation of hydrogen from formic acid/amine adducts at ambient temperature is demonstrated. The highest catalytic activity (TOF up to 3630 h−1 after 20 min) was observed in the presence of in situ generated ruthenium phosphine catalysts. Compared to the previously known methods to generate hydrogen from liquid feedstocks, the systems presented here can be operated at room temperature without the need for any high‐temperature reforming processes, and the hydrogen produced can then be directly used in fuel cells. A variety of Ru precursors and phosphine ligands were investigated for the decomposition of formic acid/amine adducts. These catalytic systems are particularly interesting for the generation of H2 for new applications in portable electric devices.
Generation of flow cytometry data files with a potentially infinite number of dimensions
Authors: Pedreira Carlos E. , Costa Elaine S. , Barrena Susana , Lecrevisse Quentin , Almeida Julia , van Dongen Jacques J. M. , Orfao Alberto 
Published: July 2008

AbstractImmunophenotypic characterization of B‐cell chronic lymphoproliferative disorders (B‐CLPD) is associated with the use of increasingly larger panels of multiple combinations of 3 to ≥6 monoclonal antibodies (Mab), data analysis being separately performed for each of the different stained sample aliquots. Here, we describe and validate an automated method for calculation of flow cytometric data from several multicolor stainings of the same cell sample—i.e., the merging of data from different aliquots stained with partially overlapping combinations of Mab reagents (focusing on ≥1 cell populations)—into one data file as if it concerned a single “super” multicolor staining. Evaluation of the performance of the method described was done in a group of 60 B‐CLPD studied at diagnosis with 18 different reagents in a panel containing six different 3‐ and 4‐color stainings, which systematically contained CD19 for the identification of B‐cells. Our results show a high degree of correlation and agreement between originally measured and calculated data about cell surface stainings, providing a basis for the use of this approach for the generation of flow cytometric data files containing information about a virtually infinite number of stainings for each individual cellular event measured in a sample, using a limited number of fluorochrome stainings. © 2008 International Society for Advancement of Cytometry
Polychromatic plots: Graphical display of multidimensional data
Authors: Roederer Mario , Moody M. Anthony 
Published: July 2008

AbstractLimitations of graphical displays as well as human perception make the presentation and analysis of multidimensional data challenging. Graphical display of information on paper or by current projectors is perforce limited to two dimensions; the encoding of information from other dimensions must be overloaded into the two physical dimensions. A number of alternative means of encoding this information have been implemented, such as offsetting data points at an angle (e.g., three‐dimensional projections onto a two‐dimensional surface) or generating derived parameters that are combinations of other variables (e.g., principal components). Here, we explore the use of color to encode additional dimensions of data. PolyChromatic Plots are standard dot plots, where the color of each event is defined by the values of one, two, or three of the measurements for that event. The measurements for these parameters are mapped onto an intensity value for each primary color (red, green, or blue) based on different functions. In addition, differential weighting of the priority with which overlapping events are displayed can be defined by these same measurements. PolyChromatic Plots can encode up to five independent dimensions of data in a single display. By altering the color mapping function and the priority function, very different displays that highlight or de‐emphasize populations of events can be generated. As for standard black‐and‐white dot plots, frequency information can be significantly biased by this display; care must be taken to ensure appropriate interpretation of the displays. PolyChromatic Plots are a powerful display type that enables rapid data exploration. By virtue of encoding as many as five dimensions of data independently, an enormous amount of information can be gleaned from the displays. In many ways, the display performs somewhat like an unsupervised cluster algorithm, by highlighting events of similar distributions in multivariate space. Published 2008 Wiley‐Liss, Inc.
Morphogenesis of the node and notochord: The cellular basis for the establishment and maintenance of left–right asymmetry in the mouse
Authors: Lee Jeffrey D. , Anderson Kathryn V. 
Published: July 2008

AbstractEstablishment of left–right asymmetry in the mouse embryo depends on leftward laminar fluid flow in the node, which initiates a signaling cascade that is confined to the left side of the embryo. Leftward fluid flow depends on two cellular processes: motility of the cilia that generate the flow and morphogenesis of the node, the structure where the cilia reside. Here, we provide an overview of the current understanding and unresolved questions about the regulation of ciliary motility and node structure. Analysis of mouse mutants has shown that the motile cilia must have a specific structure and length, and that they must point posteriorly to generate the necessary leftward fluid flow. However, the precise structure of the motile cilia is not clear and the mechanisms that position cilia on node cells have not been defined. The mouse node is a teardrop‐shaped pit at the distal tip of the early embryo, but the morphogenetic events that create the mature node from cells derived from the primitive streak are only beginning to be characterized. Recent live imaging experiments support earlier scanning electron microscopy (SEM) studies and show that node assembly is a multi‐step process in which clusters of node precursors appear on the embryo surface as overlying endoderm cells are removed. We present additional SEM and confocal microscopy studies that help define the transition stages during node morphogenesis. After the initiation of left‐sided signaling, the notochordal plate, which is contiguous with the node, generates a barrier at the embryonic midline that restricts the cascade of gene expression to the left side of the embryo. The field is now poised to dissect the genetic and cellular mechanisms that create and organize the specialized cells of the node and midline that are essential for left–right asymmetry. Developmental Dynamics 237:3464–3476, 2008. © 2008 Wiley‐Liss, Inc.
Live imaging of cell protrusive activity, and extracellular matrix assembly and remodeling during morphogenesis in the frog, Xenopus laevis
Authors: Davidson Lance A. , Dzamba Bette D. , Keller Ray , Desimone Douglas W. 
Published: July 2008

AbstractCell motility and matrix assembly have traditionally been studied in isolation because of a lack of suitable model systems in which both can be observed simultaneously. With embryonic tissues from the gastrulating frog Xenopus laevis we observe stages of fibronectin fibrillogenesis coincident with protrusive activity in the overlying cells. Using live confocal time‐lapse images collected from Cy3‐tagged fibronectin and plasma membrane tethered green fluorescent protein, we describe the movement and the elaboration of a complex fibrillar network undergoing topological rearrangements of fibrils on the surface of an embryonic tissue. Discrete processes of annealing, polymerization, stretching, breaking, and recoiling are recorded. Elaboration and maintenance of the complex topology of the extracellular matrix appears to require filamentous actin. These findings support a mechanical‐model in which cell tractive forces elaborate the complex topological fibrillar network and are part of a homeostatic mechanism for the regulation of the extracellular matrix. Developmental Dynamics 237:2684–2692, 2008. © 2008 Wiley‐Liss, Inc.
Formation of the asymmetric pineal complex in zebrafish requires two independently acting transcription factors
Authors: Snelson Corey D. , Burkart Jarred T. , Gamse Joshua T. 
Published: July 2008

AbstractThe pineal complex of zebrafish consists of a pineal organ and a left‐sided parapineal organ. Mutation of the floating head (flh) gene, which encodes a homeodomain protein, causes premature termination of pineal cell division without affecting specification or asymmetric placement of the parapineal. The from beyond (fby) mutation, a premature stop codon in the T‐domain‐containing protein Tbx2b, disrupts formation of the parapineal while leaving the pineal largely intact. However, flh is reported as being required for tbx2b transcription. To resolve the paradox that flhand tbx2b mutants have opposite phenotypes but have been placed in the same genetic pathway, we have examined transcriptional cross‐regulation in single flh or fby mutants and genetic epistasis in double mutants. Careful analysis shows that flh is not required for tbx2b transcription and double mutants exhibit an additive phenotype. We conclude that Flh and Tbx2b regulate separate programs of pineal and parapineal development. Developmental Dynamics 237:3538–3544, 2008. © 2008 Wiley‐Liss, Inc.
Characterization of primary cilia and Hedgehog signaling during development of the human pancreas and in human pancreatic duct cancer cell lines
Authors: Nielsen Sonja K. , Møllgård Kjeld , Clement Christian A. , Veland Iben R. , Awan Aashir , Yoder Bradley K. , Novak Ivana , Christensen Søren Tvorup 
Published: July 2008

AbstractHedgehog (Hh) signaling controls pancreatic development and homeostasis; aberrant Hh signaling is associated with several pancreatic diseases. Here we investigated the link between Hh signaling and primary cilia in the human developing pancreatic ducts and in cultures of human pancreatic duct adenocarcinoma cell lines, PANC‐1 and CFPAC‐1. We show that the onset of Hh signaling from human embryogenesis to fetal development is associated with accumulation of Hh signaling components Smo and Gli2 in duct primary cilia and a reduction of Gli3 in the duct epithelium. Smo, Ptc, and Gli2 localized to primary cilia of PANC‐1 and CFPAC‐1 cells, which may maintain high levels of nonstimulated Hh pathway activity. These findings indicate that primary cilia are involved in pancreatic development and postnatal tissue homeostasis. Developmental Dynamics 237:2039–2052, 2008. © 2008 Wiley‐Liss, Inc.
Role for primary cilia in the regulation of mouse ovarian function
Authors: Johnson Ellen T. , Nicola Teodora , Roarty Kevin , Yoder Bradley K. , Haycraft Courtney J. , Serra Rosa 
Published: July 2008

AbstractIft88 is a component of the intraflagellar transport complex required for formation and maintenance of cilia. Disruption of Ift88 results in depletion of cilia. The goal of the current study was to determine the role of primary cilia in ovarian function. Deletion of Ift88 in ovary using Cre‐Lox recombination in mice resulted in a severe delay in mammary gland development including lack of terminal end bud structures, alterations in the estrous cycle, and impaired ovulation. Because estrogen drives the formation of end buds and Cre was expressed in the granulosa cells of the ovary, we tested the hypothesis that addition of estradiol to the mutant mice would compensate for defects in ovarian function and rescue the mammary gland phenotype. Mammary gland development including the formation of end bud structures resumed in mutant mice that were injected with estradiol. Together the results suggest that cilia are required for ovarian function. Developmental Dynamics 237:2053–2060, 2008. © 2008 Wiley‐Liss, Inc.
Msx1 and Msx2 are expressed in sub‐populations of vascular smooth muscle cells
Authors: Goupille Olivier , Saint Cloment Cécile , Lopes Miguel , Montarras Didier , Robert Benoît 
Published: July 2008

AbstractUsing an nlacZ reporter gene inserted at the Msx1 and Msx2 loci, we could analyze the expression of these homeogenes in the adult mouse. We observed that Msx genes are prominently expressed in a subset of blood vessels. The Msx2nlacZ allele is mainly expressed in a restricted population of mural cells in peripheral arteries and veins. Msx1nlacZ is expressed to a lesser extent by vascular smooth muscle cells of peripheral arteries, but is highly expressed in arterioles and capillaries, making Msx1 a novel marker for a subpopulation of pericytes. Expression is set up early in developing vessels and maintained throughout life. In addition, expression of both genes is observed in a few endothelial cells of the aorta at fetal stages, and only Msx2 continues to be expressed in this layer at the adult stage. These results suggest major functions for Msx genes in vascular mural cell formation and remodeling. Developmental Dynamics 237:2187–2194, 2008. © 2008 Wiley‐Liss, Inc.
Xenopus zinc finger transcription factor IA1 (Insm1) expression marks anteroventral noradrenergic neuron progenitors in Xenopus embryos
Authors: Parlier Damien , Ariza Ana , Christulia Fotini , Genco Flavio , Vanhomwegen Jessica , Kricha Sadia , Souopgui Jacob , Bellefroid Eric J. 
Published: July 2008

AbstractThe evolutionarily conserved IA1 (Insm1) gene is strongly expressed in the developing nervous system. Here, we show that IA1 is expressed during Xenopus laevis embryogenesis in neural plate primary neurons as well as in a population of uncharacterized anteroventral cells that form in front of the cement gland and that we identified as noradrenergic neurons. We also show that the formation of those anteroventral cells is dependent on BMPs and inhibited by Notch and that it is regulated by the transcription factors Xash1, Phox2, and Hand2. Finally, we provide functional evidence suggesting that IA1 may also play a role in their formation. Together, our results reveal that IA1 constitutes a novel player downstream of Xash1 in the formation of a previously unidentified population of Xenopus noradrenergic primary neurons. Developmental Dynamics 237:2147–2157, 2008. © 2008 Wiley‐Liss, Inc.
Gene nomenclature guidelines for the planarian Schmidtea mediterranea
Authors: Reddien Peter W. , Newmark Phillip A. , Alvarado Alejandro Sánchez 
Published: July 2008

AbstractWe describe a gene nomenclature system for the freshwater planarian Schmidtea mediterranea. Guidelines are specified for designating names for genes and proteins, as well as for describing RNA‐mediated genetic interference (RNAi) experiments. The proposed conventions aim to avoid multiple names being ascribed to single genes and to establish a uniform, simple method for naming genes in S. mediterranea that is readily understood by researchers working on planarians and other organisms. Developmental Dynamics 237:3099–3101, 2008. © 2008 Wiley‐Liss, Inc.