bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dendrimeric Oligo(phenylenevinylene)‐Extended Dithieno[3,2‐b:2′,3′‐d]phospholes—Synthesis, Self‐Organization, and Optical Properties
Authors: Romero‐Nieto Carlos , Merino Sonia , Rodríguez‐López Julián , Baumgartner Thomas 
Published: March 2009

AbstractA boost from the branches: Incorporation of the dithieno[3,2‐b:2′,3′‐d]phosphole system as a core in oligo(phenylenevinylene) dendrimers (an example is shown here) provides materials that exhibit energy‐transfer features relaying incoming photons from the dendrons towards the core, which in turn shows enhanced emission intensity. The optical properties and self‐assembly features of the dendrimers can be impacted by the terminal groups (‐H, ‐CF3, or ‐NPh2) employed.magnified imageTo establish this system as a fluorescent core in π‐conjugated dendrimers, a series of oligo(phenylenevinylene) (OPV)‐extended dithieno[3,2‐b:2′,3′‐d]phospholes has been prepared by means of a Wittig–Horner protocol with a dithienophosphole dialdehyde and appropriately functionalized phosphonates. The “zero‐generation” model compounds have provided the general accessibility of OPV‐functionalized dithienophospholes, and show varying emission colors covering the optical spectrum from green to red. Expansion of the synthetic strategy towards the corresponding first‐generation dendrimers has provided materials that show intriguing self‐organization features in case of the phenyl‐terminated dendrimer, forming large one‐dimensional microfibres, as well as desirable energy‐transfer processes from the dendrons to the dithienophoshole core resulting in an enhanced emission intensity for the latter. The present study has revealed that the terminal end‐groups of the OPV branches have significant impact on the optical features of the OPV dendrimers as a whole.
A Bisfullerene–Bis(dipyrrinato)zinc Complex: Electronic Coupling and Charge Separation in an Easy‐to‐Assemble Synthetic System
Authors: Rio Yannick , Sánchez‐García David , Seitz Wolfgang , Torres Tomás , Sessler Jonathan L. , Guldi Dirk M. 
Published: March 2009

AbstractGetting connected: The use of a bis(dipyrrinato)zinc(II)) linker allows the facile tethering of two C60 subunits and gives rise to an electronically coupled system that allows effective charge separation following photoexcitation (see figure).magnified image
Rapid and Tunable Patterning of High Purity ZnO Nanoarrays without Template or Catalyst
Authors: Wang Xiaolei , Zhu Hui , Yang Wen , Yang Fan , Yang Xiurong 
Published: March 2009

AbstractArrays of endless possibility: Without template or catalyst, high‐purity ZnO nanoarrays were patterned though a rapid, tunable and repeatable method (see picture). Their potential contributions in both electrical and biomedical fields were also discussed and demonstrated.magnified image
Overlap domain decomposition method for bioluminescence tomography (BLT)
Authors: Wang Tao , Gao Shuping , Zhang Ling , Wu Yan , He Xiaowei , Hou Yanbin , Huang Heyu , Tian Jie 
Published: March 2009

AbstractBioluminescence tomography (BLT) allows in vivo localization and quantification of bioluminescent sources inside a small animal to reveal various molecular and cellular activities. In this paper, the overlap domain decomposition method (ODDM) of BLT is proposed, which refers to divide and conquer techniques for solving BLT by iteratively solving sub‐problems on smaller sub‐domains. Here, two triangulations of the region are adopted. We can obtain the photon density distribution on the object surface, as well as reconstruct the position of the light source by using ODDM and genetic algorithm. The numerical simulations have shown that ODDM is computationally efficient and fairly robust. Copyright © 2009 John Wiley & Sons, Ltd.
Dynamic regulation of the P2X4 receptor in alveolar macrophages by phagocytosis and classical activation
Authors: Stokes Leanne , Surprenant Annmarie 
Published: March 2009

AbstractATP‐gated P2X4 receptors (P2X4R) in macrophages and microglia have been implicated in neuropathic and inflammatory pain by currently unidentified mechanisms. P2X4R are found predominantly in intracellular lysosomal compartments but can be rapidly trafficked to the surface membrane by procedures that induce endolysosomal secretion. We studied total and surface membrane P2X4R protein expression by Western blot and biotinylation assays and functional expression by whole‐cell patch clamp assays in human and rat alveolar macrophages in response to phagocytosis of zymosan and opsonized zymosan bioparticles and to classical and alternative macrophage activation. Unstimulated macrophages showed high total protein expression but very low functional expression. Phagocytosis rapidly (within 4 h) increased functional P2X4R expression by 2‐ to 7‐fold as did chloroquine, an agent known to induce lysosomal secretion. In contrast, classical activation of macrophage for 48 h with IFN‐γ and TNF‐α or IFN‐γ and LPS reduced surface and functional P2X4R expression by 3‐fold without altering total P2X4R protein levels. Alternative activation with IL‐4 or IL‐13 did not alter total, surface or functional expression of P2X4R. This is the first study of the regulation of P2X4R in macrophages by physiological stimuli and presents a picture whereby P2X4R become functional in response to initial phagocytic stimuli but return to a non‐functional state during sustained activation by classical macrophage activation.
Loss of FOXP3 expression in natural human CD4+CD25+ regulatory T cells upon repetitive in vitro stimulation
Authors: Hoffmann Petra , Boeld Tina J. , Eder Ruediger , Huehn Jochen , Floess Stefan , Wieczorek Georg , Olek Sven , Dietmaier Wolfgang , Andreesen Reinhard , Edinger Matthias 
Published: March 2009

AbstractThe adoptive transfer of CD4+CD25+ natural regulatory T cells (Treg) is a promising strategy for the treatment of autoimmune diseases and the prevention of alloresponses after transplantation. Clinical trials exploring this strategy require efficient in vitro expansion of this rare cell population. Protocols developed thus far rely on high‐grade purification of Treg prior to culture initiation, a process still hampered by the lack of Treg cell‐specific surface markers. Depletion of CD127+ cells was shown to separate activated conventional T cells from natural Treg cell populations allowing the isolation of highly enriched FOXP3+ cells with all functional and molecular characteristics of natural Treg. Here, we demonstrate that upon in vitro expansion, CpG methylation in a conserved region within the FOXP3 gene locus increased in CD4+CD25+CD127low Treg, correlating with loss of FOXP3 expression and emergence of pro‐inflammatory cytokines. Further analysis identified CD45RA−FOXP3+ memory‐type Treg as the main source of converting cells, whereas CD45RA+FOXP3+ Treg from the same donors showed no conversion within 3 wk of in vitro expansion. Thus, Treg cell lineage differentiation does not seem to represent a final fate decision, as natural Treg can lose their cell‐type‐specific characteristics after repetitive TCR stimulation.
IL‐17/Th17 in anti‐fungal immunity: What's new?
Authors: Zelante Teresa , De Luca Antonella , D' Angelo Carmen , Moretti Silvia , Romani Luigina 
Published: March 2009

AbstractHow the immune system tailors protective responses to suit the infectious challenge while limiting damage to the host is an emerging theme in T‐cell biology. Although many studies have focused on the pathological aspects of IL‐17‐producing T cells in many autoimmune diseases, their role in protective anti‐microbial immunity has also been increasingly recognized. This increased recognition also applies to their role in anti‐fungal immunity; however, the role of IL‐17‐producing T cells in protection versus pathology in fungal infections is still controversial. Although both positive and negative effects on immune resistance have been attributed to the IL‐23/Th17 axis in experimental models of fungal infections, defective Th17 cell differentiation has been linked to recurrent pneumonia by filamentous fungi and the occurrence of mucocutaneous candidiasis in patients with primary immunodeficiencies. Here we discuss how recent findings in experimental candidiasis and aspergillosis shed new lights on the contribution of Th17 cells to resistance and pathology to fungi.
Novel therapeutic targets along the Th17 pathway
Authors: Ouyang Wenjun , Filvaroff Ellen , Hu Yan , Grogan Jane 
Published: March 2009

AbstractThe recent discovery of IL‐17‐producing CD4+ Th subset significantly revised the Th1/Th2 dichotomy model proposed by Mosmann and Coffman almost two decades ago. Th17 cells are involved in the pathogenesis of many human autoimmune diseases. Th17 cells, their developmental pathways and their effector functions, therefore, provide novel therapeutic targets.
Thymus‐specific serine protease regulates positive selection of a subset of CD4+ thymocytes
Authors: Gommeaux Julien , Grégoire Claude , Nguessan Prudence , Richelme Mireille , Malissen Marie , Guerder Sylvie , Malissen Bernard , Carrier Alice 
Published: March 2009

AbstractThymus‐specific serine protease (TSSP) was initially reported as a putative protease specifically expressed in the endosomal compartment of cortical thymic epithelial cells (cTEC). As such, TSSP is potentially involved in the presentation of the self‐peptides that are bound to MHC class II molecules expressed at the cTEC surface and are involved in the positive selection of CD4+ thymocytes. We tested this hypothesis by generating mutant mice deprived of Prss16, the gene encoding TSSP. TSSP‐deficient mice produced normal numbers of T cells, despite a decrease in the percentage of cTEC expressing high surface levels of MHC class II. By using sensitive transgenic models expressing MHC class II‐restricted TCR transgenes (Marilyn and OT‐II), we showed that the absence of TSSP markedly impaired the selection of Marilyn and OT‐II CD4+ T cells. In contrast, selection of CD8+ T cells expressing an MHC class I‐restricted TCR transgene (OT‐I) was unaffected. Therefore, TSSP is involved in the positive selection of some CD4+ T lymphocytes and likely constitutes the first serine protease to play a function in the intrathymic presentation of self‐peptides bound to MHC class II complexes.
Environmental control of Th17 differentiation
Authors: Quintana Francisco J. , Weiner Howard L. 
Published: March 2009

AbstractTh17 cells participate in the control of extracellular bacteria and fungi, but dysregulated Th17 cell activity can result in immunopathology. Thus, the generation and the activity of Th17 cells should be tightly regulated, and simultaneously it should be able to respond to the challenges presented by a changing environment. In this viewpoint, we discuss some of the mechanisms by which microbes, dietary components and environmental toxins influence the Th17 response.
Host versus pathogen: Two sides of the same challenge in the TB world
Authors: Cooper Andrea M. 
Published: March 2009

AbstractHumans have studied tuberculosis for many thousands of years. For most of this time investigations were focused on describing patient symptoms with the hope of ameliorating them and perhaps limiting the spread of disease. At the end of the 19th century, however, the association between the bacterium and disease was demonstrated 1 – a discovery recognized annually on 24 March by World TB Day, a day that also highlights efforts to eliminate the disease. Following the discovery, the study of the disease split in two directions: the nature of the pathogen and the nature of the host response. A key advance to be celebrated this World TB Day 2009 is that we are now in a position to integrate the study of the bacteria with that of the host response and thereby create a more complete understanding of how this pervasive disease develops. With this improved understanding more efficient and targeted intervention will be forthcoming.
Gold(I) Complexes of N‐Heterocyclic Carbenes and Pyridines
Authors: Chiou Josh Y. Z. , Luo Shih C. , You Wan C. , Bhattacharyya Amitabha , Vasam C. Sekhar , Huang Cyong H. , Lin Ivan J. B. 
Published: March 2009

AbstractOverall ten ionic [Au(NHC)(Py)][PF6]‐ and [Au2(NHC)2(Py)2][PF6]2‐type complexes [NHC = N,N′‐dialkylbenzimidazol‐2‐ylidene, denoted as R2‐bimy with alkyl (R) being methyl (Me) or ethyl (Et), and Py = 4‐substituted pyridine or 4,4′‐bipyridine] have been prepared by incorporating various Pys into the AuI‐NHC core with Au(NHC)Cl as starting material. Their crystal structures characterized by X‐ray diffraction indicate a linearly coordinated AuI center and exhibit secondary forces such as Au···Au, Au···π, or π···π interactions. The luminescent properties of these compounds were studied in the solid state. Density‐functional theory calculations on [Au(Me2‐bimy)(4‐dmapy)][PF6] [4‐dmapy = 4‐(dimethylamino)pyridine] predict the lowest electronic transition with nonzero oscillator strength is the fourth HOMO–LUMO transition. Whereas the fourth HOMO is mainly associated with the Py ligands, the LUMO is predominantly aurophilic. Four AuI‐NHC compounds were examined for their catalytic activity towards the oxidation of benzyl alcohol to aldehyde, in which the starting material [Au(Et2‐bimy)Cl] gave the highest yield. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Structural Evidence for an Unusual Conformation and Weak Interligand Interactions in Two Copper Chelates with (o‐Nitrophenyl)ethylenediaminediacetic Acid
Authors: Allali Mustapha , Jaud Joël , Habbadi Nouzha , Dartiguenave Michèle , Beauchamp André L. , Benoist Eric 
Published: March 2009

AbstractTwo mixed‐ligand copper(II) complexes, [Cu(L1)(H2O)]·H2O (1) and [Cu(L1)(bipy)]·2H2O (2), containing the title N‐substituted iminodiacetate (IDA) derivative (L12–) as primary ligand with and without 2,2′‐bipyridine as auxiliary ligand, have been synthesised. Both have been fully characterised by means of IR spectroscopy, mass spectrometry, elemental analysis and conductimetry, as well as X‐ray crystallography. The dominant structural feature of these complexes is the presence of a flexible coordinating arm on the IDA skeleton which controls the conformation of the resulting complexes. The CuII centre in complex 1 exhibits a distorted square‐pyramidal [4+1] coordination in which the apical site is unexpectedly occupied by the N(2) atom of the coordinating arm instead of a water molecule. The IDA skeleton adopts a tridentate mer‐O2N arrangement in 1, whereas in 2 it exhibits an unusual fac‐O2N(apical) configuration, which is observed for the first time for a tridentate IDA unit bearing a flexible arm containing a coordinating atom. The o‐nitro aromatic group in the flexible arm gives rise to different inter‐ and/or intramolecular stacking interactions. Classic intermolecular “nitrophenyl‐nitrophenyl” π‐π stacking interactions are observed between pairs of complex molecules in crystals of 1, whereas intramolecular “nitrophenyl‐pyridyl” interactions alternate with unprecedented interligand π‐π “nitrophenyl–metal chelate ring” interactions in crystals of 2.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
The Nature of the Metal–Carbene Bond in Normal and Abnormal Pyridylidene, Quinolylidene and Isoquinolylidene Complexes
Authors: Heydenrych Greta , von Hopffgarten Moritz , Stander Elzet , Schuster Oliver , Raubenheimer Helgard G. , Frenking Gernot 
Published: March 2009

AbstractQuantum chemical calculations using DFT at the BP86/TZ2P level of theory are reported for the complexes (PH3)2ClM‐L where L is an N‐heterocyclic ligand and M a group‐10 metal Ni, Pd and Pt. The ligands comprise pyridyl groups or carbenes derived from the pyridine, quinolidine or isoquinolidine systems wherein the nitrogen atom is either adjacent to the carbene carbon atom or it is in a remote (meta or para, or in the adjacent ring) position. Comparative calculations include the isomeric ligands of the well‐known five‐membered N‐heterocyclic carbene. The nature of the metal–ligand interactions are investigated by energy decomposition analysis (EDA). The EDA results suggest that the nature of the metal–carbene bonds in the complexes shows little variation when the position of the nitrogen atom in pyridylidenes is adjacent (ortho) or remote (meta or para). It changes even very little when the nitrogen atom is in an adjacent ring to the cyclic carbene moiety. The most significant differences between the bond strengths come from the energy level of the σ‐HOMO of the carbene ligand which depends largely on the position of the nitrogen atom. An energetically higher‐lying σ lone‐pair orbital of the carbene ligand yields stronger orbital interactions but also stronger electrostatic attraction because of better overlap with the metal nucleus. This holds also for the isomers of the five‐membered N‐heterocyclic carbenes. An excellent correlation is established between the ϵ(HOMO) values of the ligands and the metal–ligand interaction energies, ΔEint.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Polyhedral Boranes for Medical Applications: Current Status and Perspectives
Authors: Sivaev Igor B. , Bregadze Vladimir V. 
Published: March 2009

AbstractThis review focuses on the current status and perspectives of the application of polyhedral boron hydrides in medicine. The main topics discussed are boron neutron capture therapy for cancer and radionuclide diagnostics and therapy. X‐ray contrast diagnostics, antitumor activity of some metal derivatives of carboranes, and drug design including carborane fragments are discussed as well.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
A New Class of Stable, Saturated N‐Heterocyclic Carbenes with N‐Naphthyl Substituents: Synthesis, Dynamic Behavior, and Catalytic Potential
Authors: Vieille‐Petit Ludovic , Luan Xinjun , Mariz Ronaldo , Blumentritt Sascha , Linden Anthony , Dorta Reto 
Published: March 2009

AbstractA new family of easily accessible and stable imidazolin‐2‐ylidenes has been synthesized, where the side chains are comprised of substituted naphthyl units. This generates C2‐symmetric (anti) and Cs‐symmetric (syn) atropisomers. The interconversion between the isomers is studied in detail both for the N‐heterocyclic carbene salts and the free carbenes through variable‐temperature 1H NMR spectroscopic studies; activation free energies are calculated and can be linked to the substitution pattern of the naphthyl moieties. Palladium complexes comprising the new N‐heterocyclic carbenes are synthesized and preliminary data show that these compounds behave well as precatalysts in the Buchwald–Hartwig amination reaction of aryl bromides and aryl chlorides. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Insight into cis‐to‐trans Olefin Isomerisation Catalysed by Group 4 and 6 Cyclopentadienyl Compounds
Authors: Chahboun Ghaita , Petrisor Cristina E. , Gómez‐Bengoa Enrique , Royo Eva , Cuenca Tomás 
Published: March 2009

AbstractIntramolecular isomerisation of the pendant allyl unit present in the model compound [MoH(η5‐C5H4SiMe2CH2CH=CH2)(CO)3] reported before was investigated by DFT calculations. The coordination of CO and the splitting of the agostic Mo–H interactions found in metallacyclic transition states stabilise the cis and trans hydride compounds [MoH(η5‐C5H4SiMe2CH=CHCH3)(CO)3] relative to the corresponding tricarbonyl molybdenum alkyl metallacycles. A comparison with an analogous zirconium system is included. To contrastthese results with the behaviour of metal hydride cyclopentadienyl compounds, which have no intramolecular alkene functionality, group 4 and 6 derivatives such as [Zr(η5‐C5H4SiMe2‐η1‐NtBu)(η5‐C5H4SiMe2CH2CH2‐η1‐CH2)] (2), [MH(η5‐C5HMe4)(CO)3] [M = Mo (3), W (4)], and [ZrH(η5‐C5H4SiMe2‐η1‐NtBu)(η5‐C5H4R)] [R = H (5), SiMe3 (6)] were examined as selective catalysts for the intermolecular isomerisation of the terminal olefins allyltrimethylsilane (A) and 4‐methyl‐1‐pentene (B). Zirconium hydride compounds were the most efficient catalysts. Compound 4 catalysed the same reaction but required heating at 140 °C, whereas compound 3 was inactive due to a dehydrogenation process, which produced the dinuclear compound [Mo(η5‐C5HMe4)(CO)3]2 (7). Reaction of 4 and 5 with the internal alkenes trimethyl(1‐propenyl)silane (C) and 4,4‐dimethyl‐2‐pentene (D) favoured cis‐to‐trans isomer conversion with poor production of the corresponding terminal olefins. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Highly Efficient Visible‐Light‐Induced Photocleavage of DNA by a Ruthenium‐Substituted Fluorinated Porphyrin
Authors: Cunningham Michelle , McCrate Anna , Nielsen Mark , Swavey Shawn 
Published: March 2009

AbstractA new porphyrin, meso‐5‐(pentafluorophenyl)‐10,15,20‐tris(4‐pyridyl)porphyrin, has been synthesized. Coordination of two [Ru(bipy)2Cl]+ moieties (where bipy = 2,2′‐bipyridine) to the pyridyl nitrogen atoms in the 10,15‐positions gives the target complex. Electronic transitions associated with the ruthenium–porphyrin include an intense Soret band and four less intense Q‐bands in the visible region of the spectrum. An intense π–π* transition in the UV region associated with the bipyridyl groups and a metal‐to‐ligand charge‐transfer (MLCT) band appearing as a shoulder to the Soret band are also observed. Electrochemical properties associated with the complex include a redox couple in the cathodic region with E1/2 = –0.84 V vs. Ag/AgCl attributed to the porphyrin and a redox couple in the anodic region at E1/2 = 0.79 V vs. Ag/AgCl due to the RuIII/II couple. DNA titrations and ethidium bromide displacement experiments indicate the ruthenium porphyrin interacts with DNA potentially through a partial intercalation mechanism. Irradiation of aqueous solutions of the ruthenated complex and supercoiled DNA at a 100:1 base pair/complex ratio with visible light above 400 nm indicates that the complex causes double‐strand breaks of the DNA.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Biodiesel from canola oil using a 1 : 1 molar mixture of methanol and ethanol
Authors: Joshi Hem , Toler Joe , Moser Bryan R. , Walker Terry 
Published: March 2009

AbstractCanola oil was transesterified using a 1 : 1 molar mixture of methanol and ethanol (M/E) with potassium hydroxide (KOH) catalyst. The effects of catalyst concentration (0.5–1.5 wt‐%), molar ratio of M/E to canola oil (3 : 1 to 20 : 1) and reaction temperature (25–75 °C) on the percentage yield measured after 2.5 and 5.0 min were optimized using a central composite design. A maximum percentage yield of 98% was obtained for a catalyst concentration of 1.1 wt‐% and an M/E to canola oil molar ratio of 20 : 1 at 25 °C at 2.5 min, whereas a maximum percentage yield of 99% was obtained for a catalyst concentration of 1.15 wt‐% and all molar ratios of reactants at 25 °C at 5 min. Statistical analysis demonstrated that increasing catalyst concentration and molar ratio of reactants resulted in curvilinear and linear trends in percentage yield, both at 2.5 and 5 min. However, reaction temperature, which affected the percentage yield at 2.5 min linearly, was insignificant at 5 min. The resultant mixed methyl/ethyl canola esters exhibited enhanced low‐temperature performance and lubricity properties in comparison to neat canola oil methyl esters and also satisfied ASTM D6751 and EN 14214 standards with respect to oxidation stability, kinematic viscosity, and acid value.