bluuebunny/crossref_metadata_2025 huggingface dataset:
Reducing peak power for coded OFDM systems by multiple symbol mapping
Authors: Harada Masaaki , Yamamoto Takaya , Okada Hiraku , Katayama Masaaki , Ogawa Akira
Published: November 2006

In this paper, we propose a method for reducing the peak power of the signal for orthogonal frequency division multiplex (OFDM) system in which convolutional code is used for an error‐correcting code. In the system, the bit sequence encoded using a convolutional code is mapped onto the multiple symbols which may constrain the peak power of the signal. In the conventional scheme, encoded bits are mapped onto a symbol sequentially. In such a method, the symbols assigned to each subcarrier are mutually uncorrelated and it is therefore difficult to let the symbols have a correlation with other symbols to constrain the peak power of the OFDM signal. In the proposed scheme, the encoded bit sequence is mapped onto the multiple symbols in which each symbol is correlated such as to reduce the peak power of the signal. In this way we are able to keep the peak power of the OFDM signal lower than that of the conventional scheme. For further performance improvement, set partitioning is performed to a set of multiple symbols to increase the Euclidean distance. This approach is made possible bymultiple trellis‐coded modulation(MTCM) that applies set partitioning to multiple symbols. We evaluate the performance of the proposed scheme in the presence of the effects of nonlinear amplification and show that the proposed scheme is effective for nonlinear amplification. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 90(3): 67–76, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.10168
Src homology 2 domain‐containing protein tyrosine phosphatase substrate 1 regulates the induction of Langerhans cell maturation
Authors: Fukunaga Atsushi , Nagai Hiroshi , Yu Xijun , Oniki Shuntaro , Okazawa Hideki , Motegi Sei‐ichiro , Suzuki Ryuji , Honma Nakayuki , Matozaki Takashi , Nishigori Chikako , Horikawa Tatsuya
Published: November 2006

Recently, we reported that Src homology 2 domain‐containing protein tyrosine phosphatase substrate 1 (SHPS‐1) plays an important role in the migration of Langerhans cells (LC). Here, we show that SHPS‐1 is involved in the maturation of LC. Immunofluorescence analysis on epidermal sheets for I‐A or CD86 revealed that LC maturation induced by 2,4‐dinitro‐1‐fluorobenzene (DNFB) or by TNF‐α was inhibited by pretreatment with an anti‐SHPS‐1 monoclonal antibody (mAb) or with CD47‐Fc fusion protein, a ligand for SHPS‐1. Further, FACS analysis demonstrated that I‐A+ LC that had emigrated from skin explants expressed CD80 or CD86, whereas CD47‐Fc protein reduced CD80high+ or CD86high+ cells. CD47‐Fc protein also reduced the up‐regulation of surface CD80 or CD86 by LC remaining in the skin explants. In SHPS‐1 mutant mice, we observed that the up‐regulation of surface CD86 and CCR7 by LC induced by DNFB as well as that of surface CD80 and CD86 by LC in skin explants was attenuated. Finally, contact hypersensitivity (CHS) response was suppressed in SHPS‐1 mutant mice and in wild‐type mice treated with an anti‐SHPS‐1 mAb. These observations indicate that SHPS‐1 plays an important role in the maturation of LC ex vivo and in vivo, and that SHPS‐1‐CD47 interaction may negatively regulate CHS.
Expression and role of phosphatidylcholine‐specific phospholipase C in human NK and T lymphocyte subsets
Authors: Spadaro Francesca , Cecchetti Serena , Sanchez Massimo , Ausiello Clara Maria , Podo Franca , Ramoni Carlo
Published: November 2006

We recently reported evidence of phosphatidylcholine‐specific phospholipase C (PC‐PLC) involvement in NK cell‐mediated cytotoxicity and in lytic granule exocytosis. In the present study, different subpopulations of human PBL were investigated in relation to PC‐PLC enzyme expression. While a substantial intracellular amount of PC‐PLC was detected in all lymphoid subsets, expression of this enzyme on the outer membrane surface reached high levels only in NK cells, was present at low levels in B lymphocytes and in some TCR gamma/delta T cells and was practically absent in CD4+ and CD8+ T lymphocytes. Moreover, in NK cells two different subpopulations were identified, CD56dim PC‐PLCbright and CD56bright PC‐PLClow/– cells, corresponding to distinct subsets with cytolytic and immunoregulatory functions, respectively. Interestingly, the PC‐PLC expression level on the NK membrane surface correlated closely with that of the CD16 receptor, suggesting a possible relationship between enzyme externalization and NK cell maturation. In summary, our results suggest that a high PC‐PLC expression on the cell membrane surface of PBL is a peculiarity of NK cytolytic cells, in which the enzyme is apparently involved in the ability of this subset to lyse sensitive target cells.
Immunosuppressive components of Ascaris suum down‐regulate expression of costimulatory molecules and function of antigen‐presenting cells via an IL‐10‐mediated mechanism
Authors: Silva Sandriana R. , Jacysyn Jacqueline F. , Macedo Mahasti S. , Faquim‐Mauro Eliana L.
Published: November 2006

High‐molecular‐weight components (PI) of Ascaris suum suppress both cell‐mediated and humoral responses against ovalbumin (OVA) via an IL‐4/IL‐10‐dependent mechanism. The aim of this work was to investigate the effect of PI on the ability of APC to activate T cells and the role of IL‐10 in this process. Flow cytometry analyses of MHC class II, CD80, CD86 and CD40 molecules on LN cells from mice immunized with OVA or OVA+PI showed that PI inhibits expression of these molecules on unfractionated cells and on purified CD11c+ cells. A low proliferative response was obtained when OVA‐specific TCR‐Tg T cells were incubated with CD11c+ cells from OVA+PI‐immunized mice pulsed with OVA, when compared to those incubated with cells from OVA‐immunized mice. Similar results were obtained using as APC CD11c+ cells from OVA‐immunized mice pulsed with OVA+PI, which also expressed less of the four markers. The inhibitory effect of PI on both the expression of costimulatory molecules and the induction of T cell proliferation was abolished in IL‐10‐deficient mice. Our data indicate that the potent immunosuppressive effect of A. suum extract components on the host immune system is primarily related to their property of down‐regulating the Ag‐presenting ability of DC via an IL‐10‐mediated mechanism.
α2,3‐Sialyltransferase‐IV is essential for L‐selectin ligand function in inflammation
Authors: Sperandio Markus , Frommhold David , Babushkina Inna , Ellies Lesley G. , Olson Timothy S. , Smith Michael L. , Fritzsching Benedikt , Pauly Eva , Smith David F. , Nobiling Rainer , Linderkamp Otwin , Marth Jamey D. , Ley Klaus
Published: November 2006

L‐selectin belongs to the C‐type lectin family of glycoproteins and is constitutively expressed on most leukocytes. L‐selectin mediates leukocyte rolling in inflamed microvessels and high endothelial venules (HEV) via binding to specific carbohydrate structures on selectin ligands. Previous studies using sialidase treatment suggested a role of sialic acid residues in L‐selectin‐dependent rolling. To investigate the role of the α2,3‐sialyltransferase (ST3Gal)‐IV on L‐selectin ligand activity in vivo, we studied leukocyte rolling in inflamed venules of the cremaster muscle and in Peyer's patch HEV of ST3Gal‐IV‐deficient mice and littermate control mice. In cremaster muscle venules with or without TNF‐α treatment, L‐selectin‐dependent rolling was almost completely abolished in ST3Gal‐IV–/– mice. In both models, L‐selectin interacts with P‐selectin glycoprotein ligand‐1 (PSGL‐1) presented by adherent leukocytes and leukocyte fragments, but not with endothelial L‐selectin ligands. In contrast, L‐selectin‐dependent rolling in Peyer's patch HEV, which is mediated by unknown endothelial L‐selectin ligands, was not impaired in the absence of ST3Gal‐IV. Our in vivo data show that PSGL‐1, the molecule responsible for L‐selectin‐mediated leukocyte interactions in inflammation, is dependent on ST3Gal‐IV, while α2,3‐sialylation by ST3Gal‐IV is not necessary for L‐selectin ligand activity on high endothelial cells of Peyer's patch HEV.
CD4+ T cells specific for a model latency‐associated antigen fail to control a gammaherpesvirus in vivo
Authors: Smith Christopher M. , Rosa Gustavo T. L. , May Janet S. , Bennett Neil J. , Mount Adele M. , Belz Gabrielle T. , Stevenson Philip G.
Published: November 2006

CD4+ T cells play a major role in containing herpesvirus infections. However, their cellular targets remain poorly defined. In vitro CD4+ T cells have been reported to kill B cells that harbor a latent gammaherpesvirus. We used the B cell‐tropic murine gammaherpesvirus‐68 (MHV‐68) to test whether this also occurred in vivo. MHV‐68 that expressed cytoplasmic ovalbumin (OVA) in tandem with its episome maintenance protein, ORF73, stimulated CD8+ T cells specific for the H2‐Kb‐restricted OVA epitope SIINFEKL and was rapidly eliminated from C57BL/6 (H2b) mice. However, the same virus failed to stimulate CD4+ T cells specific for the I‐Ad/I‐Ab‐restricted OVA323–339 epitope. We overcame any barrier to the MHC class II‐restricted presentation of an endogenous epitope by substituting OVA323–339 for the CLIP peptide of the invariant chain (ORF73‐IRES‐Ii‐OVA), again expressed in tandem with ORF73. This virus presented OVA323–339 but showed little or no latency deficit in either BALB/c (H2d) or C57BL/6 mice. Latent antigen‐specific CD4+ T cells therefore either failed to recognize key virus‐infected cell populations in vivo or lacked the effector functions required to control them.
The structure of the human allo‐ligand HLA‐B*3501 in complex with a cytochrome p450 peptide: Steric hindrance influences TCR allo‐recognition
Authors: Hourigan Christopher S. , Harkiolaki Maria , Peterson Neil A. , Bell John I. , Jones E. Yvonne , O'Callaghan Chris A.
Published: November 2006

Virus‐specific T cell populations have been implicated in allo‐recognition. The subdominant T cell receptor JL12 recognizes both HLA‐B*0801 presenting the Epstein–Barr virus‐derived peptide FLRGRAYGL and also HLA‐B*3501 presenting the cytochrome p450 self peptide KPIVVLHGY. This cross‐reactivity could promote the rejection of HLA‐B*3501‐positive cells in Epstein–Barr virus‐exposed HLA‐B*0801 recipients. LC13, the dominant TCR against the HLA‐B*0801:FLRGRAYGL complex, fails to recognize HLA‐B*3501:KPIVVLHGY. We report the 1.75‐Angstrom resolution crystal structure of the human allo‐ligand HLA‐B*3501:KPIVVLHGY. Similarities between this structure and that of HLA‐B*0801:FLRGRAYGL may facilitate cross‐recognition by JL12. Moreover, the elevated peptide position in HLA‐B*3501:KPIVVLHGY would provide steric hindrance to LC13, preventing it from interacting in the manner in which it interacts with HLA‐B*0801:FLRGRAYGL. These findings are relevant to understanding the basis of T cell cross‐reactivity in allo‐recognition, optimal transplant donor‐recipient matching and developing specific molecular inhibitors of allo‐recognition.
Immunomodulatory effects associated with a live vaccine against Leishmania major containing CpG oligodeoxynucleotides
Authors: Wu Wenhui , Weigand Luise , Belkaid Yasmine , Mendez Susana
Published: November 2006

The inoculation of live Leishmania major to produce a lesion that heals (leishmanization) is to date the only vaccine against cutaneous leishmaniasis that has proven effective in humans, but it still has an unacceptable frequency of large ulcerating lesions that are slow to heal or, in rare cases, non‐healing. We have previously shown that C57BL/6 mice vaccinated intradermally with 104 L. major/50 µg CpG oligodeoxynucleotides develop little or no dermal lesions and show early containment of parasite growth in the vaccination site, eliminating safety concerns related to the inoculation of live organisms. The addition of CpG to the live vaccine resulted in early activation of dermal dendritic cells and increased IL‐6 production, as well as in a reduction in the accumulation of Foxp3+CD4+CD25+ regulatory T (Treg) cells that naturally occurs in the skin following Leishmania infection. Neutralization of IL‐6 caused the development of larger lesions and increased local Treg cell numbers. Transfer of vaccine‐primed dendritic cells into IL‐6‐deficient mice mitigated lesion development, indicating that IL‐6 reconstitution limited pathology in the vaccination site.
Activation‐induced cell death of human melanoma specific cytotoxic T lymphocytes is mediated by apoptosis‐inducing factor
Authors: Chhabra Arvind , Mehrotra Shikhar , Chakraborty Nitya G. , Dorsky David I. , Mukherji Bijay
Published: November 2006

Activation‐induced cell death (AICD) of T cells can be an impediment towards achieving a robust and long‐lived cytolytic T lymphocyte (CTL) response from active specific immunization or after adoptive cell transfer in cancer immunotherapy. The mechanism of AICD in primary CTL, however, remains poorly understood. It is widely believed that AICD is driven by signals from death receptors (DR) and that the cell death takes place in a caspase‐dependent manner, although it has been shown that AICD of T cells can be induced by internal triggers and that death takes place in a caspase‐independent manner. We show here that AICD in human melanoma epitope‐specific primary CTL involves selective mitochondrio‐nuclear translocation of the apoptosis inducing factor (AIF) without cytochrome c release, caspase‐3 and caspase‐8 activation, and results from large‐scale DNA fragmentation. The c‐jun‐N terminal kinase (JNK) inhibitor, SP600125, blocks the mitochondrio‐nuclear translocation of AIF and prevents AICD in these CTL. These findings suggest that the AICD in human melanoma epitope specific primary CTL is mediated by mitochondrial AIF release and JNK is involved in regulation of this death process.
Expression and function of NKG2D in CD4+ T cells specific for human cytomegalovirus
Authors: Sáez‐Borderías Andrea , Gumá Mónica , Angulo Ana , Bellosillo Beatriz , Pende Daniela , López‐Botet Miguel
Published: November 2006

The human NKG2D killer lectin‐like receptor (KLR) is coupled by the DAP10 adapter to phosphoinositide 3‐kinase (PI3 K) and specifically interacts with different stress‐inducible molecules (i.e. MICA, MICB, ULBP) displayed by some tumour and virus‐infected cells. This KLR is commonly expressed by human NK cells as well as TCRγδ+ and TCRαβ+CD8+ T lymphocytes, but it has been also detected in CD4+ T cells from rheumatoid arthritis and cancer patients. In the present study, we analysed NKG2D expression in human cytomegalovirus (HCMV)‐specific CD4+ T lymphocytes. In vitro stimulation of peripheral blood mononuclear cells (PBMC) from healthy seropositive individuals with HCMV promoted variable expansion of CD4+NKG2D+ T lymphocytes that coexpressed perforin. NKG2D was detected in CD28– and CD28dull subsets and was not systematically associated with the expression of other NK cell receptors (i.e. KIR, CD94/NKG2 and ILT2). Engagement of NKG2D with specific mAb synergized with TCR‐dependent activation of CD4+ T cells, triggering proliferation and cytokine production (i.e. IFN‐γ and TNF‐α). Altogether, the data support the notion that NKG2D functions as a prototypic costimulatory receptor in a subset of HCMV‐specific CD4+ T lymphocytes and thus may have a role in the response against infected HLA class II+ cells displaying NKG2D ligands.
Synthesis and Structure of [nPr3N(CH2)6NnPr3][CuFe3Br3(SePh)6], [Cu5Fe(SePh)7(PPh3)4] and [Cu4Fe3(SePh)10(PPh3)4]
Authors: Eichhöfer Andreas , Fenske Dieter , Olkowska‐Oetzel Jolanta
Published: November 2006

CuBr and Fe(OOCCH3)2 react with PhSeSiMe3 in acetonitrile in the presence of the diammonium salt [nPr3N(CH2)6NnPr3]Br2 to yield ionic [nPr3N(CH2)6NnPr3][CuFe3Br3(SePh)6]. The neutral complexes [Cu5Fe(SePh)7(PPh3)4] and [Cu4Fe3(SePh)10(PPh3)4] were obtained by similar reactions of different stoichiometric mixtures of CuOOCCH3 and FeCl2 with PPh3 and PhSeSiMe3. The crystal structures of the compounds were determined by single‐crystal X‐ray analysis to give new structural types of molecular cluster compounds formed by copper, iron and selenium. Thermal treatment of [Cu5Fe(SePh)7(PPh3)4] and [Cu4Fe3(SePh)10(PPh3)4] resultsin the formation of mixtures of binary Cu2Se and ternaryCuFeSe2.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Synthesis and Crystal Structure of Three Carborane Complexes, [M{7,8‐(OPPh2)2‐7,8‐C2B9H10}2] (M = Cu, Zn) and [Ni(thf){7,8‐(OPPh2)2‐7,8‐C2B9H10}2]·thf, and Two Carborane Compounds, 1‐(OPPh2)‐2‐(PPh2)‐1,2‐C2B10H10 and H[7,8‐(OPPh2)2‐7,8‐C2B9H10]·0.25C2H5OH
Authors: Dou Jianmin , Zhang Daopeng , Li Dacheng , Wang Daqi
Published: November 2006

Three new carborane complexes containing the bis(phosphoryl)‐nido‐carborane ligand, [Cu{7,8‐(OPPh2)2‐7,8‐C2B9H10}2] (1), [Zn{7,8‐(OPPh2)2‐7,8‐C2B9H10}2] (2), and [Ni(thf){7,8‐(OPPh2)2‐7,8‐C2B9H10}2]·thf (3), were synthesized by the reactions of 1,2‐(PPh2)2‐1,2‐C2B10H10 with CuCl2·2H2O, ZnCl2, and NiCl2·6H2O, respectively, in ethanol in air. Two other compounds, 1‐(OPPh2)‐2‐(PPh2)‐1,2‐C2B10H10 (4) and H[7,8‐(OPPh2)2‐7,8‐C2B9H10]·0.25C2H5OH (5), were also obtained through the oxidation of the closo ligand in air. All new compounds were characterized by elemental analysis, FT‐IR, 1H and 13C NMR spectroscopy, and single‐crystal X‐ray diffraction. In complexes 1 and 2, the metal atoms are coordinated to the four oxygen atoms of the two bidentate bis(phosphoryl) ligands [7,8‐(OPPh2)2‐7,8‐C2B9H10]– and adopt a square‐planar geometry. For complex 3, the molecular structure reveals that the geometry at the nickel atom is square‐pyramidal, with four oxygen atoms from the four OPPh2 groups and one additional one from a thf molecule. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
The Transient Titanocene(II): Direct Synthesis from Solvated Titanium(II) Chloride and Cyclopentadienylsodium and Ensuing Interception with Diphenylacetylene as 1,1‐Bis(cyclopentadienyl)‐2,3,4,5‐tetraphenyltitanacyclopentadiene
Authors: Eisch John J. , Adeosun Adetenu A. , Birmingham John M.
Published: November 2006

For the first time the unstable titanocene(II) has been directly synthesized by the Wilkinson metallocene approach, namely the interaction of a THF‐soluble form of titanium(II) chloride with two equivalents of cyclopentadienylsodium in THF solution at 0°–25 °C. Because of the transient existence of the titanocene(II) thereby obtained, it could only be chemically trapped in high yield as 1,1‐bis(cyclopentadienyl)‐2,3,4,5‐tetraphenyltitanacyclopentadiene by two equivalents of diphenylacetylene, if the acetylene was added at 25 °C, without removal of the by‐product LiCl and NaCl. If the addition of the acetylene was delayed, in order to filter off the LiCl and NaCl from the reaction mixture, then no trace of the titanacyclopentadiene derivative was found upon hydrolytic workup. Instead, a significant portion of the acetylene was found to have undergone hydrotitanation. This finding is clear evidence that the titanocene(II) had undergone a precedented rearrangement to a known dimer having the structure of a titanocene(III) hydride with a fulvalene bridge between the titanium centers. We suggest that the LiCl and NaCl present in the unfiltered reaction mixture form a dichloro complex with titanocene(II) and thereby retard its dimerizing rearrangement to the titanocene(III) hydride. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Competing Radical and Non‐Radical Pathways for the Decomposition of LFeII(H2O2) Complexes: a Density Functional Study
Authors: Anastasi Anna E. , Lienke Achim , Comba Peter , Rohwer Heidi , McGrady John E.
Published: November 2006

Density functional theory has been used to explore the mechanism of hydrogen peroxide decomposition when coordinated to a bispidone iron(II) complex. Two quite distinct pathways are identified, one involving O–O bond homolysis followed by a “rebound” hydrogen atom abstraction, the other involving proton transfer followed by O–O bond heterolysis. A water molecule in the second coordination sphere plays a key role in both pathways. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Synthesis and Characterisation of WVI Complexes of Phosphane Oxide Ligands, [WO2X2(OPR3)2] (X = F, Cl or Br; R = Me or Ph), and of the [MoO2F2(OPR3)2]
Authors: Davis Martin F. , Levason William , Ratnani Raju , Reid Gillian , Rose Tim , Webster Michael
Published: November 2006

Phosphane oxide complexes of dioxidotungstenVI, [WO2X2(OPR3)2] (X = Cl or Br, M = Ph or Me) have been prepared under anhydrous conditions from the reaction of WX6 with (Me3Si)2O in CH2Cl2, followed by addition of OPR3. Some diphosphane dioxide analogues have been made similarly, viz, [WO2X2(L–L)] {L–L = Ph2P(O)(CH2)nP(O)Ph2 (n = 1 or 2), o‐C6H4[P(O)Ph2]2}. The complexes have been characterised by elemental analysis, IR and NMR (1H and 31P{1H}) spectroscopy, and the structures of [WO2Br2(OPPh3)2] and [WO2Cl2(OPMe3)2] determined, revealing distorted six‐coordinate tungsten centres with cis‐WO2 and trans‐WX2 units. The difluorido‐dioxido complexes [MO2F2(OPR3)2] (M = Mo or W) and [WO2F2(L′–L′)] (L′–L′ = 2,2′‐bipyridyl, 1,10‐phenanthroline) have been prepared by fluorination of the corresponding chlorido complexes with Me3SnF in CH2Cl2. These are characterised similarly and by 19F{1H} NMR spectroscopy. Attempts to make [MO2I2(OPR3)2] were unsuccessful. No adduct formation occurs between CrO2Cl2 and OPPh3 under rigorously anhydrous conditions. Crystal structures of [Me3SnCl(OPPh3)] and two forms of [WO2Cl2(1,10‐phen)] are also reported and discussed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Valence‐State Distribution in the Ruthenium o‐Quinonoid Systems [Ru(trpy)(Cl)(L1)]+ and [Ru(trpy)(Cl)(L2)]+ (L1 = o‐Iminobenzoquinone, L2 = o‐Diiminobenzoquinone; trpy = 2,2′:6′,2″‐Terpyridine)
Authors: Maji Somnath , Patra Srikanta , Chakraborty Saumen , Janardanan Deepa , Mobin Shaikh M. , Sunoj Raghavan B. , Lahiri Goutam Kumar
Published: November 2006

Valence‐state distributions in the ruthenium quinonoid (L) frameworks of [Ru(trpy)(Cl)(L1)]ClO4 (1‐ClO4) and [Ru(trpy)(Cl)(L2)]ClO4 (2‐ClO4) (L1 = o‐iminobenzoquinone, L2 = o‐diiminobenzoquinone, and trpy = 2,2′:6′,2″‐terpyridine) have been examined by structural, spectroelectrochemical, and density functional studies. The structural data, in corroboration with the DFT‐calculated bond lengths, suggest that the primary valence formulation of 1+ and 2+ is a spin‐coupled singlet configuration of [RuIII(trpy)(Cl)(LSq)]+ with a minority contribution from diamagnetic [RuII(trpy)(Cl)(LQ)]+. Consequently, the closely spaced successive two oxidation processes of 1+ and 2+ can be assigned to RuIII→RuIV and LSq→LQ, which involve the HOMO and HOMO–3 levels, respectively. The one‐electron‐oxidized species 12+ and 22+ display sharp EPR signals with g values of 2.011 and 2.014 at 77 K, respectively. The free radical EPR signal (g ≈ 2.0) of the one‐electron‐reduced species 1 or 2 signifies the preferential involvement of the ruthenium‐based orbitals in the first reduction process to yield [RuII(trpy)(Cl)(LSq)], although the LUMO is calculated to be a mixture of dπ(Ru) (≈24 %) and π*(L) (≈ 70 %). The subsequent second (1–/2–) and third (12–/22–) reduction steps in each case are associated simply with the terpyridyl‐based orbitals (≥90 %). The lowest energy charge‐transfer transitions of 1+ and 2+ at 556 and 509 nm are predicted to be HOMO → LUMO+1 and HOMO–1 → LUMO+1 transitions, respectively. In the successive oxidations 1+/2+ → 12+/22+ → 13+/23+ the lowest energy charge‐transfer transitions undergo a blue shift with a substantial reduction in intensity. The lowest energy charge‐transfer transitions, however, are red shifted with a reduction in intensity on going from (1+/2+) to 1/2. The origin of the transitions in the 12+/22+ and 1/2 systems is predicted by TDDFT analysis. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Resonance Raman Spectroscopy with Overtones Involving Metal‐Ligand and Ligand‐Centered Modes in (o‐Benzoquinonediimine)ruthenium(II) Complexes
Authors: Beaulac Rémi , Lever A. B. P. , Reber Christian
Published: November 2006

Resonance Raman spectra of (o‐benzoquinonediimine)ruthenium(II) complexes measured with visible excitation wavelengths show distinct resonance enhancements and intense overtone and combination bands. Assignments of the most prominent fundamental bands are made on the basis of comparisons with theoretical spectra obtained from DFT calculations. Excited state distortions are determined from the resonance Raman intensities and lead to calculated luminescence and absorption spectra in good agreement with experiment. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Bonding Properties Related with Chiral Discrimination in Dinuclear Metal Complexes of Group 10
Authors: Picazo Oscar , Alkorta Ibon , Elguero José , Sundberg Markku R. , Valo Jaana
Published: November 2006

A series of neutral dinuclear homo‐ and heterochiral complexes formed by hydrazine (a molecule with axial chirality), a metal atom of group 10 (Ni, Pd, Pt), and halogen atoms (F, Cl, Br, I) was studied by computational methods including density functional theory. In the optimized structures the heterochiral complexes were always found to be energetically favored. The chiral discrimination depends on the contributions coming from the metal atoms and the halogen anions attached to them. Moreover, the relative energies of the optimized complexes are correlated with the electronegativity of the metals and the halogens as well as with the relative distances of the bond critical points in the metal–nitrogen bonds. Also the smaller deviation of the ligand–metal–ligand angles from the ideal value of 90° corresponds to the heterochiral complexes. An analysis of the bonding properties reveals a complex mechanism for the behavior of the electron lone pairs of the nitrogen and halogen atoms. The electronic properties of the optimized complexes were studied by NBO (Natural Bond Orbital) and QTAIM (Quantum Theory of Atoms in Molecules) methods. An NBO analysis of the energy differences between the stabilizing energies related to the interactions between an electron lone pair of the coordinated nitrogen atom and the opposite M–X antibonding orbital explain the differences of the total energies between the diastereomeric heterochiral and homochiral complexes. The stabilizing energies have systematically more negative values in the heterochiral complexes; this can be interpreteted as a measure of the trans influence. Small energy values related to the cis influence were found mainly in the nickel complexes. The M–N bonds in the heterochiral complexes are more polar with a higher bond order than that in the homochiral ones, as shown by QTAIM methods. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
The Poly(Radical Cation) of a Star‐Shaped Oligoarylamine — Detection of Excited High‐Spin States
Authors: Hirao Yasukazu , Ishizaki Haruya , Ito Akihiro , Kato Tatsuhisa , Tanaka Kazuyoshi
Published: November 2006

The intramolecular spin–spin interaction in the highly oxidized species of a star‐shaped oligoarylamine, namely hexakis{4‐[bis(p‐methoxyphenyl)amino]phenyl}benzene (1), in which six diphenylamine units are introduced as redox‐active sites into a central hexaphenylbenzene core, has been investigated by EPR spectroscopy. The hexacation‐rich sample was prepared by chemical oxidation with 7.5 equivalents. of [bis(trifluoroacetoxy)iodo]benzene (PIFA) in the presence of 10 vol.‐% trifluoroacetic acid (TFA) in dichloromethane at 195 K. Variable‐temperature EPR measurements provided the non‐Curie temperature dependence of the signal intensity. The fine structure of the EPR spectrum also varies with temperature. In order to identify the spin multiplicity of the generated poly(radical cation), we carried out electron spin transient nutation (ESTN) measurements based on pulsed EPR spectroscopy at various temperatures. From the ESTN spectra, it was found that the high‐spin states are thermally populated with increasing temperature. These results indicate the low‐spin ground state of the poly(radical cation) of 1. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
A Microwave‐Assisted Heck Reaction in Poly(ethylene glycol) for the Synthesis of Benzazepines
Authors: Declerck Valérie , Ribière Patrice , Nédellec Yannig , Allouchi Hassan , Martinez Jean , Lamaty Frédéric
Published: November 2006

The Heck reaction of alkylated 2‐(trimethylsilyl)ethanesulfonyl (SES)‐protected β‐amino esters provides benzazepines in good yields. Good selectivity towards cyclisation was obtained when the reaction was performed in PEG 3400 as the solvent under microwave activation. Cleavage of the SES group with HF provides the corresponding free benzazepine. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Prepared to eat: how immediate affective and motivational responses to food cues are influenced by food deprivation
Authors: Seibt Beate , Häfner Michael , Deutsch Roland
Published: November 2006

Three studies examined how food deprivation influences the immediate valence of food stimuli as well as spontaneous motivational tendencies toward them. We assumed that immediate reactions towards food stimuli should be tuned to the basic needs of the organism. In Study 1, the immediate valence of food names as a function of need state was assessed using an Implicit Association Test (IAT) in a quasi‐experimental design. Food deprivation led to a more positive immediate valence of food items. In Study 2, these results were replicated using the Extrinsic Affective Simon Task. In Study 3, immediate motivational reactions toward pictorial food stimuli were assessed. As hypothesized, approach reactions were facilitated for participants tested before as compared to after lunch, even in a sample with eating disorders. We thus conclude that the immediate valence of edible objects partially reflects regulation in the service of need fulfillment. Copyright © 2006 John Wiley & Sons, Ltd.
Development of Quantum Dots Modified Acetylcholinesterase Biosensor for the Detection of Trichlorfon
Authors: Li Xiao‐Hua , Xie Zonghong , Min Hong , Li Chenxin , Liu Meichuan , Xian Yuezhong , Jin Litong
Published: November 2006

Poly (N‐vinyl‐2‐pyrrolidone) (PVP)‐capped CdS quantum dots (QCdS‐PVP) was synthesized with CdCl2 and Na2S in the presence of PVP. QCdS‐PVP has been used for the immobilization and stabilization of the acetylcholinesterase (AChE). The electrocatalytic activity of QCdS‐PVP leads to a greatly improved electrochemical detection of the enzymatically generated thiocholine product, and higher sensitivity and stability. The GCE/QCdS‐PVP/AChE biosensor was used for the detection of organophosphate pesticides (OPs), such as trichlorfon. The sensor performance, including pH and inhibition time, was optimized with respect to operating conditions. Under the optimal conditions, the biosensor was used to measure as low as 12 ppb trichlorfon with a 5‐min inhibition time.
Nucleophilic Addition of Thiaproline to Electrochemically Derived o‐Quinone, Application to the Sensitive Voltammetric Detection of Thiaproline
Authors: Shahrokhian Saeed , Amiri Mandana
Published: November 2006

The mechanism of electrochemical behavior of catechol in the presence of thiaproline is investigated by cyclic voltammetry, controlled‐potential coulometry and spectrophotometric tracing of the reaction coordinate. The results indicate that thiaproline participate in with an ECEC mechanism in a nucleophilic (Michael) addition to o‐quinone. Effect of pH of buffer solution on reaction pathway is studied and showed that addition of thiaproline to the o‐quinone is performed only in solutions with pHs higher than 5. These results indicate that the addition of thiaproline is occurred first from amine functional group. In the second step, the addition of carboxylate group of thiaproline to C‐5 of catechol results the final product with a lactone ring in its structure. Observation of two isosbestic point in absorption spectrum during the progress of the electrolysis together with the FT‐IR results for final product can be presented as evidence for two step addition of thiaproline to catechol. Final product, due to the electron donor property of thiaproline, more easily oxidized respect to the former catechol and as a result, a new redox couple is obtained for this compound in lower potentials. The easier anodic oxidation of addition product (relative to catechol) caused to an increase in anodic current for catechol, which is proportional to the thiaproline concentration. The differential pulse voltammetry (DPV) is applied as a sensitive voltammetric method for the detection of thiaproline. A linear range from 5×10−8 to 5×10−6 M with a detection limit of 1×10−8 M is resulted for thiaproline. With respect to the reversibility of the electrochemical reactions in the mechanism, and also more facile oxidation of the addition products, the square‐wave voltammetry is presented as a method with considerably more sensitivity for the detection of sub‐micromolar amounts of thiaproline. The advantageous properties of the voltammetric method for thiaproline detection lie in its excellent catalytic activity, sensitivity and simplicity.
Micromixer utilizing electrokinetic instability‐induced shedding effect
Authors: Tai Chang‐Hsien , Yang Ruey‐Jen , Huang Min‐Zhong , Liu Chia‐Wei , Tsai Chien‐Hsiung , Fu Lung‐Ming
Published: November 2006

This paper presents a T‐shaped micromixer featuring 45° parallelogram barriers (PBs) within the mixing channel. The presented device obtains a rapid mixing of two sample fluids with conductivity ratio of 10:1 (sample concentration:running buffer concentration) by means of the electrokinetic instability‐induced shedding effects which are produced when a direct current (DC) electric field of an appropriate intensity is applied. The presented device uses a single high‐voltage power source to simultaneously drive and mix the sample fluids. The effectiveness of the mixer is characterized experimentally as a function of the applied electrical field intensity and the extent to which the PBs obstruct the mixing channel. The experimental results indicate that the mixing performance reaches 91% at a cross‐section located 2.3 mm downstream of the T‐junction when the barriers obstruct 4/5 of the channel width and an electrical field of 300 V/cm is applied. The micromixing method presented in this study provides a simple low‐cost solution to mixing problems in lab‐on‐a‐chip systems.
Atmospheric molding of ionic copolymer MALDI‐TOF/MS arrays: A new tool for protein identification/profiling
Authors: Muck Alexander , Ibáñez Alfredo J. , Stauber Einar J. , Mansourova Madina , Svatoš Aleš
Published: November 2006

An atmospheric molding protocol has been used to prepare an ionic methacrylate‐based copolymer sample support chips for MALDI (pMALDI)‐MS by targeting selected groups of various monomers copolymerized during molding, namely, carboxy, sulfo, dimethylalkyamino, and trimethylalkylammonium groups. The new disposable array chips provide analyte‐oriented enhancement of protein adsorption to the modified substrates without requiring complicated surface coating or derivatization. The MALDI‐MS performance of the new ionic copolymer chips was evaluated for lysozyme, β‐lactoglobulin A, trypsinogen and carbonic anhydrase I using washing with solutions prepared in pH or ionic strength steps. On cationic chips, the proteins are washed out at pH lower than their pI values, and on anionic chips at pH higher than their pI values. The ability of the microfabricated pMALDI chip set to selectively adsorb different proteins from real samples and to significantly increase their MS‐signal was documented for the transmembrane photosystem I protein complex from the green alga Chlamydomonas reinhardtii. The proteins were almost exclusively adsorbed according to calculated pI values and grand average of hydropathy (GRAVY) indexes. The new disposable chips reduce manipulation times and increase measurement sensitivity for real‐world proteomic samples. The simple atmospheric molding procedure enables additional proteomic operations to be incorporated on disposable MALDI‐MS integrated platforms.
Polymorphisms in the thymidylate synthase promoter and the DNA repair genes XRCC1 and XPD in a Brazilian population
Authors: Canalle Renata , Andrade Vanessa da Silva S. , Scrideli Carlos A. , Queiroz Rosane G. de Paula , Tone Luiz G.
Published: November 2006

Polymorphisms in genes responsible for maintaining genomic integrity are potential modifiers of disease risk. Since considerable interindividual and interethnic variation in DNA repair capacity has been associated with polymorphic alleles, we evaluated the frequency of the 2R/3R variants in the TS promoter, Arg194Trp and Arg399Gln in the XRCC1 gene, and Asp312Asn and Lys751Gln in the XPD gene in 364 healthy individuals from a Brazilian population separated by ethnicity (European ancestry and African ancestry). The genotypes were determined by PCR (TS) or by PCR‐RFLP (XRCC1 and XPD). The frequency of the TS 3R allele was 0.56 for whites and 0.51 for nonwhites. In the case of the XRCC1 MspI polymorphism, the allele frequencies were 0.09 for 194Trp in both nonwhites and whites and 0.27 and 0.28 for 399Gln in nonwhites and whites, respectively. For the XPD 312Asn allele, we found a frequency of 0.25 in white individuals, which was significantly different (P = 0.025) from that seen in nonwhites (0.15). Similarly, the 751Gln polymorphic allele of the XPD gene was significantly more frequent (P < 0.002) in whites (0.30) than in nonwhites (0.20). The genotype frequencies were within Hardy–Weinberg equilibrium. We concluded that the genotype and allele frequencies of XPD gene polymorphism differed between white and nonwhite Brazilians, and that the frequencies of the XPD 312Asn and XRCC1 399Gln alleles in this Brazilian population showed ethnic variability when compared with those observed in other populations. Environ. Mol. Mutagen., 2006. © 2006 Wiley‐Liss, Inc.
Skew‐symmetric distributions generated by the distribution function of the normal distribution
Authors: Gómez Héctor W. , Venegas Osvaldo , Bolfarine Heleno
Published: November 2006

In this paper we study a general family of skew‐symmetric distributions which are generated by the cumulative distribution of the normal distribution. For some distributions, moments are computed which allows computing asymmetry and kurtosis coefficients. It is shown that the range for asymmetry and kurtosis parameters is wider than for the family of models introduced by Nadarajah and Kotz (2003). For the skew‐t‐normal model, we discuss approaches for obtaining maximum likelihood estimators and derive the Fisher information matrix, discussing some of its properties and special cases. We report results of an application to a real data set related to nickel concentration in soil samples. Copyright © 2006 John Wiley & Sons, Ltd.
Carbon dioxide capture from flue gas by pressure swing adsorption at high temperature using a K‐promoted HTlc: Effects of mass transfer on the process performance
Authors: Reynolds Steven P. , Ebner Armin D. , Ritter James A.
Published: November 2006

Using hundreds (640) of simulations obtained from a cyclic adsorption process simulator, two heavy reflux (HR) pressure swing adsorption (PSA) cycles were analyzed at the periodic state for the capture and concentration of CO2 from flue gas at high temperature (575 K), using a K‐promoted hydrotalcite like compound (HTlc). Since the values of the adsorption (ka) and desorption (kd) mass transfer coefficients of CO2 in the K‐promoted HTlc were uncertain, this study focused only on the effects of ka and kd on the process performance. Both, a 5‐bed 5‐step stripping PSA cycle with light reflux (LR) and HR from LR purge and a 4‐bed 4‐step stripping PSA cycle with HR from countercurrent depressurization were studied using a vacuum swing cycle with the high pressure fixed at 137.9 kPa and the feed set at 15 vol % CO2, 75 vol % N2, and 10 vol % H2O. For the 5‐bed process, increasing both ka (= 0.0058 s−1) and kd (= 0.0006 s−1) by a factor of five increased both the CO2 purity and CO2 recovery, achieving a CO2 purity of nearly 90% at a CO2 recovery of 72% and feed throughput (θ) of 57.6 L STP/h/kg. Increasing ka and kd by a factor of ten further increased both the CO2 purity and CO2 recovery, achieving for the first time a CO2 purity greater than 90% at a CO2 recovery of 85% and θ of 57.6 L STP/h/kg. Making kd = ka (= 0.0058 s−1) resulted in a CO2 purity of 89% with a CO2 recovery of 72% at a θ of 57.6 L STP/h/kg; and increasing that value by a factor of five led to a CO2 purity of 91% at a high CO2 recovery of 88% and θ of 57.6 L STP/h/kg. These results suggested that the performance was desorption limited. For the 4‐bed process, when ka and kd were both increased by a factor of five, the CO2 purity increased to 98% at a θ of 201.7 L STP/h/kg, but the CO2 recovery decreased to 5%. Overall, it was proven that mass transfer effects were important to the performance of this high temperature CO2 recovery process, with higher but acceptable values of ka and kd leading to CO2 purities of greater than 90%, a needed limit for process viability. © 2006 American Institute of Chemical Engineers Environ Prog, 2006
Case studies of damage to 19‐storey irregular steel moment‐frame buildings under near‐source ground motion
Authors: Krishnan Swaminathan
Published: November 2006

This paper describes the three‐dimensional nonlinear analysis of six 19‐storey steel moment‐frame buildings, designed per the 1997 Uniform Building Code, under strong ground motion records from near‐source earthquakes with magnitudes in the range of 6.7–7.3. Three of these buildings possess a reentrant corner irregularity, while the remaining three possess a torsional plan irregularity. The records create drift demands of the order of 0.05 and plastic rotation demands of the order of 4–5% of a radian in the buildings with reentrant corners. These values point to performance at or near ‘Collapse Prevention’. Twisting in the torsionally sensitive buildings causes the plastic rotations on the moment frame on one face of the building (4–5% of a radian) to be as high as twice of that on the opposite face (2–3% of a radian). The asymmetric yield pattern implies a lower redundancy in the lateral force‐resisting system as the failure of the heavily loaded frame could result in a total loss of resistance to torsion. Copyright © 2006 John Wiley & Sons, Ltd.
A markup model for forecasting inflation for the euro area
Authors: Russell Bill , Banerjee Anindya
Published: November 2006

We develop a small model for forecasting inflation for the euro area using quarterly data over the period June 1973 to March 1999. The model is used to provide inflation forecasts from June 1999 to March 2002. We compare the forecasts from our model with those derived from six competing forecasting models, including autoregressions, vector autoregressions and Phillips‐curve based models. A considerable gain in forecasting performance is demonstrated using a relative root mean squared error criterion and the Diebold–Mariano test to make forecast comparisons.  Copyright © 2006 John Wiley & Sons, Ltd.
A hybrid forecasting approach for piece‐wise stationary time series
Authors: Yang Minxian , Bewley Ronald
Published: November 2006

We consider the problem of forecasting a stationary time series when there is an unknown mean break close to the forecast origin. Based on the intercept‐correction methods suggested by Clements and Hendry (1998) and Bewley (2003), a hybrid approach is introduced, where the break and break point are treated in a Bayesian fashion. The hyperparameters of the priors are determined by maximizing the marginal density of the data. The distributions of the proposed forecasts are derived. Different intercept‐correction methods are compared using simulation experiments. Our hybrid approach compares favorably with both the uncorrected and the intercept‐corrected forecasts.  Copyright © 2006 John Wiley & Sons, Ltd.
A stochastic proportional hazard model for the force of mortality
Authors: Lorenzo Emilia Di , Sibillo Marilena , Tessitore Gerarda
Published: November 2006

In order to avoid ‘frailty’ in deterministic assumptions concerning survival law, in this paper stochastic volatility in the force of mortality is considered. In particular, mortality rates are studied by means of a stochastic model of CIR type. A method for estimating its parameters is presented and an example of application, based on simulations of the process, is shown. Empirical results and comparison with a traditional model illustrate predictive performance and the flexibility of the model.  Copyright © 2006 John Wiley & Sons, Ltd.
Understanding and predicting sovereign debt rescheduling: a comparison of the areas under receiver operating characteristic curves
Authors: Rodriguez Arnulfo , Rodriguez Pedro N.
Published: November 2006

This paper extends the existing literature on empirical research in the field of sovereign debt. To the authors' knowledge, only one study in the area of sovereign debt has used a variety of statistical methodologies to test the reliability of their predictions and to compare their performance against one another. However, those comparisons across models have been made in terms of different probability cut‐off points and mean squared errors. Moreover, the issue of interpretability has not been addressed in terms of interactions among explanatory variables with their correspondent debt rescheduling threshold level. The areas under the Receiver Operating Characteristic (ROC) curves are used to compare the discrimination power of statistical models. This paper tests logit, MARS, tree‐based and neural network models. Analyses of the relative importance of variables and deviance were done. All of the models rank the previous payment history as the most important explanatory variable.  Copyright © 2006 John Wiley & Sons, Ltd.
Induction of senescence in MYCN amplified neuroblastoma cell lines by hydroxyurea
Authors: Narath R. , Ambros I. M. , Kowalska A. , Bozsaky E. , Boukamp P. , Ambros P. F.
Published: November 2006

Recently, it was shown that MYCN amplified cells spontaneously expulse extrachromosomally amplified gene copies by micronuclei formation. Furthermore, it was shown that these cells lose their malignant phenotype and start to age. We tested whether it is possible to encourage neuroblastoma tumor cells to enter the senescence pathway by low concentrations of the micronuclei‐inducing drug hydroxyurea (HU). We studied the effect of HU on 12 neuroblastoma cell lines with extra‐ or intrachromosomally amplified MYCN copies and without amplification. Two extrachromosomally amplified neuroblastoma cell lines (with double minutes) were investigated in detail. Already after 3 weeks of HU treatment, the BrdU uptake dropped to 25% of the starting cells. After 4 weeks, enlarged and flattened cells (F‐cells) and increased granularity in the majority of cells were observed. A drastic reduction of the MYCN copy number—down to one copy per cell—associated with CD44 and MHCI upregulation in up to 100% of the HU treated neuroblastoma cells was found after 5–8 weeks. Telomere length was reduced to half the length within 8 weeks of HU treatment, and telomerase activity was not detectable at this time, while being strongly expressed at the beginning. All these features and the expression of senescence‐associated‐β‐galactosidase (SA‐β‐GAL) in up to 100% of the cells support the hypothesis that these cells entered the senescence pathway. Thus, low‐dose HU is a potent senescence elicitor for tumor cells with gene amplification, possibly representing an attractive additional strategy for treatment of this subset of tumors. © 2006 Wiley‐Liss, Inc.