bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the Chemical Reaction of Matter with Antimatter
Authors: Lodi Rizzini Evandro , Venturelli Luca , Zurlo Nicola 
Published: May 2007

AbstractA chemical reaction between the building block antiatomic nucleus, the antiproton (p̄ or ${\bar H^ - }$ in chemical notation), and the hydrogen molecular ion (${H_2^ + }$) has been observed by the ATHENA collaboration at CERN. The charged pair interact via the long‐range Coulomb force in the environment of a Penning trap which is purpose‐built to observe antiproton interactions. The net result of the very low energy collision of the pair is the creation of an antiproton–proton bound state, known as protonium (Pn), together with the liberation of a hydrogen atom. The Pn is formed in a highly excited, metastable, state with a lifetime against annihilation of around 1 μs. Effects are observed related to the temperature of the ${H_2^ + }$ prior to the interaction, and this is discussed herein.
A Theoretical Study of Anion–π Interactions in Seven‐Membered Rings
Authors: Quiñonero David , Frontera Antonio , Escudero Daniel , Ballester Pablo , Costa Antonio , Deyà Pere M. 
Published: May 2007

AbstractSeveral complexes of tropylium (1) with anions are optimized at the RI‐MP2(full)/6‐31++G** level of theory. This binding unit can interact very favorably with anions, and it combines the strength of the electrostatic interaction with the directionality of the anion–π interaction. The complexes of1with anions are characterized by means of the Bader theory of “atoms‐in‐molecules,” and the physical nature of the interaction has been analyzed by means of the molecular interaction potential with polarization tool. Experimental evidence of anion–π interactions involving seven‐membered rings has been found in the solid state.
Gas‐Phase Reactions Between Thiourea and Ca2+: New Evidence for the Formation of [Ca(NH3)]2+and Other Doubly Charged Species
Authors: Trujillo Cristina , Mó Otilia , Yáñez Manuel , Salpin Jean‐Yves , Tortajada Jeanine 
Published: May 2007

AbstractThe gas‐phase reactions between Ca2+and thiourea are investigated by means of electrospray ionization/mass spectrometry experiments. The MS/MS spectra of [Ca(thiourea)]2+complexes show the appearance of new doubly charged species formed by the loss of NH3and HNCS. Other intense peaks atm/z43, 56, 60, 73, 76 and 98 are also observed, and assigned to monocations produced in different coulomb‐explosion processes. The structures and bonding characteristics of the different stationary points of the [Ca(thiourea)]2+potential energy surface (PES) were theoretically studied by DFT calculations carried out at B3LYP/cc‐pWCVTZ level. The analysis of the topology of this PES permits to propose different mechanisms for the loss of ammonia and HNCS, and to identify, them/z43, 56, 60, 73, 76 and 98 peaks as H2NCNH+, CaNH2+, H2NCS+, CaSH+, thiourea+⋅and CaNCS+ions respectively. There are significant dissimilarities between the reactivity of urea and thiourea, which are related to the lower ionization energy of the latter, and to the fact that thioenols are intrinsically more stable than enols with respect to the corresponding keto forms.
Fractal response of physiological signals to stress conditions, environmental changes, and neurodegenerative diseases
Authors: Scafetta Nicola , Moon Richard E. , West Bruce J. 
Published: May 2007

AbstractIn the past two decades the biomedical community has witnessed several applications of nonlinear system theory to the analysis of biomedical time series and the development of nonlinear dynamic models. The development of this area of medicine can best be described as nonlinear and fractal physiology. These studies have been intended to develop more reliable methodologies for understanding how biological systems respond to peculiar altered conditions induced by internal stress, environment stress, and/or disease. Herein, we summarize the theory and some of our results showing the fractal dependency on different conditions of physiological signals such as inter‐breath intervals, heart inter‐beat intervals, and human stride intervals. © 2007 Wiley Periodicals, Inc. Complexity 12: 12–17, 2007
Generation of mice deficient for Lbx2, a gene expressed in the urogenital system, nervous system, and Pax3 dependent tissues
Authors: Wei Ke , Chen Jiyuan , Akrami Kevan , Sekhon Rashmi , Chen Fabian 
Published: May 2007

AbstractLbx2 is a member of the ladybird family of homeobox genes. The first murine ortholog identified, Lbx1, is required for hypaxial musculature and dorsal spinal cord neuron development. The second murine ortholog, Lbx2, is expressed in the developing urogenital and nervous systems. To elucidate the function of Lbx2, we generated a gene‐targeted allele of Lbx2 in mice. Lbx2 deficiency did not impair mouse development, and Lbx2 null mice appeared healthy and fertile. Replacement of Lbx2 by the lacZ gene provides a valuable histological marker for Lbx2‐expressing cells. Given the important role of Pax3 in neural crest, we intercrossed our Lbx2 deficient mice with Splotch Pax3 mutant mice to determine if Pax3 affects Lbx2 expression. There was reduced Lbx2 expression in dorsal root ganglia and cranial nerve ganglia with Pax3 deficiency, but not in the genital tubercle. This suggested that Pax3 is required for Lbx2 expression in affected neural crest‐derived tissues. genesis 45:361–368, 2007. Published 2007 Wiley‐Liss, Inc.
Synthesis of Cycloruthenated Compounds as Potential Anticancer Agents
Authors: Leyva Lida , Sirlin Claude , Rubio Laura , Franco Cecilia , Le Lagadec Ronan , Spencer John , Bischoff Pierre , Gaiddon Christian , Loeffler Jean‐Philippe , Pfeffer Michel 
Published: May 2007

AbstractA library of 19 cycloruthenated derivatives is constructed by making use of the well‐known cyclometalation reaction. Their geometries are modified in a straightforward manner by addition of either mono‐ or bidentate ligands, such as bipyridine, phenanthroline, 1,2‐bis(diphenylphosphanyl)ethane, dimethylphenylphosphane, triphenylphosphane, and 1,3,5‐triaza‐7‐phosphatricyclo[3.3.1.1]decane (PTA) ligands, to cationic cycloruthenated centers. The antitumor properties of the compounds thus obtained are investigated in order to compare them with recently reported ruthenium complexes and cisplatin. IC50values against mammalian cells (A‐172, HCT‐116, and RDM‐4) are determined for the library compounds and some of them, such as those derived from orthoruthenated phenylpyridine and a bidentate N,N ligand, display activity of the same order of magnitude as cisplatin. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Synthesis and Photophysical Properties of Bis‐Cyclometallated Iridium(III)–Styryl Complexes and Their Saturated Analogues
Authors: Lepeltier Marc , Lee Terence Kwok‐Ming , Lo Kenneth Kam‐Wing , Toupet Loic , Le Bozec Hubert , Guerchais Véronique 
Published: May 2007

AbstractThis manuscript reports the synthesis and photophysical investigation of a series of IrIII complexes Ir(C∧N)2(O∧O) which are functionalized in the para position of the pyridine ring by styryl groups substituted with electron‐donor and ‐acceptor end groups. The saturated derivative Ir(C∧N‐ppy‐4‐CH2CH2C6H4OMe)2(O∧O‐acac) (4a‐H2) was formed from [Ir(C∧N‐ppy‐4‐CH=CHC6H4OMe)2]2(μ‐Cl)2 (3a) at 140 °C, whereas at 80 °C the parent unsaturated complexes Ir(C∧N‐ppy‐4‐CH=CHC6H4R)2(O∧O) [OO = acac, R = OMe (4a), NEt2 (4b), H (4c), NO2 (4d); OO = dpm, R = OMe (5a), NEt2 (5b)] were isolated. The saturated complex 4a‐H2 exhibits intense green emission with a 36 % quantum yield at 298 K. The styryl complexes 4a–4d, 5a and 5b are very weakly emissive at 298 K, but show intense red luminescence in alcohol glass at 77 K. The amino‐ and nitro‐substituted complexes 4b and 4d give low‐energy emission (λem = 651 and 647 nm, respectively). The emissive states of these complexes are believed to possess predominant triplet intra‐ligand charge‐transfer (3ILCT) and metal‐to‐ligand charge‐transfer (3MLCT) character, respectively. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Synthesis, Characterization and Stability of Spirodiene Complexes of Molybdenum(II): New Route to ansa‐Molybdenocene and Ring‐Functionalized Molybdenocene Compounds
Authors: Honzíček Jan , Almeida Paz Filipe A. , Romão Carlos C. 
Published: May 2007

AbstractThe reactions of [Mo(CO)2(Cp)(NCCH3)2][BF4] (1) with spiro[2.4]hepta‐4,6‐diene and spiro[4.4]nona‐1,3‐diene give the complexes [Mo{η4‐C5H4(CH2)2}(CO)2(Cp)][BF4] (3) and [Mo{η4‐C5H4(CH2)4}(CO)2(Cp)][BF4] (4), respectively. [Mo{η4‐C5H4(CH2)2}(CO)2(Cp)][BF4] (3) is stable towards ring opening at room temperature, but its formation is accompanied by small amounts of ring‐opening products [Mo(η5‐C5H4CH2‐η1‐CH2)(CO)(Cp)][BF4] (5) and [Mo{η5‐C5H4(CH2)2‐η1‐CO}(CO)(Cp)][BF4] (6). With 1,1‐dimethyl‐spiro[2.4]hepta‐4,6‐diene, two isomers with the formula [Mo{η4‐C5H4CH2C(CH3)2}(CO)2(Cp)][BF4] are formed (7 and 8). While the endo‐isomer 7 is stable towards ring opening, the exo‐isomer 8 slowly rearranges to the ring‐opened product [Mo{η5‐C5H4C(CH3)2CH2‐η1‐CO}(CO)(Cp)][BF4] (9). The reaction of [Mo(CO)2(Ind)(NCCH3)2][BF4] (2) with spiro[4.4]nona‐1,3‐diene also gives the diene coordinated species [Mo{η4‐C5H4(CH2)4}(CO)2(Ind)][BF4] (11), which is the first example of a structurally characterized, coordinated, unsubstituted spirodiene. In contrast, reaction of 2 with spiro[2.4]hepta‐4,6‐diene leads directly to the ansa‐cyclopentadienyl complex [Mo(η5‐C5H4CH2‐η1‐CH2)(CO)(Ind)][BF4] (12). Reaction of 12 with bromine or iodine leads to the formation of Cp‐substituted molybdenocene derivatives [Mo{η5‐C5H4(CH2)2X}(CO)(Ind)X][BF4] (13: X = Br, 14: X = I). The compounds [Mo(η5‐C5H4CH2‐η1‐CH2)(CO)(Ind)][BF4] (12) and [MoBr{η5‐C5H4(CH2)2Br}(CO)(Ind)][Br]·0.5H2O (13a) were structurally characterized, and they open the way to new functionalized molybdenocene complexes that have biological applications.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Substituent Effects on the Stereoelectronic and Chemical Properties of a Novel Phosphapalladacycle
Authors: Ng Joseph Kok‐Peng , Chen Shuli , Tan Geok‐Kheng , Leung Pak‐Hing 
Published: May 2007

AbstractA novel phosphapalladacycle was prepared by direct cyclopalladation of the ligand (diphenylmethyl)diphenylphosphane (2). The corresponding μ‐chloro five‐membered phosphapalladacycle 3 was obtained by heating a toluene solution of 2 and Pd(OAc)2 followed by chloride ion metathesis. An optical resolution procedure was then employed by separation of the (S)‐prolinato derivatives 4 by fractional crystallization followed by treatment with dilute hydrochloric acid to yield both enantiopodes of the dimers 3 in the optically active forms. The current phosphapalladacycle was noted to display different properties with respect to the analogous phosphapalladacycle prepared from (diphenylmethyl)di‐tert‐butylphosphane. For instance, the phosphapalladacycle based on the (diphenylmethyl)di‐tert‐butylphosphane was shown to be conformationally rigid. In contrast, the analogous five‐membered phosphapalladacycle of phosphane 2 was noted to exist in both the δ and λ conformations in the solid state, while a flattened conformation was observed in solution. In addition, the (diphenylmethyl)di‐tert‐butylphosphane‐based phosphapalladacycle was noted to exhibit a much more improved regioselectivity towards ancillary ligands such as (S)‐prolinate and triphenylphosphane than 2. Furthermore, the μ‐chloro dimer 3 of the current palladacycle was shown to be lacking in thermodynamic stability of the Pd–C bond that was noted for the tBu analogue. In contrast, the Pd–C bonds of dimer 3 were immediately ruptured in the presence of concentrated HCl to give rise to the binuclear complex 5, in which the phosphane was coordinated in the η1‐P coordination mode.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Influence of the Polypyridyl (pp) Ligand Size on the DNA Binding Properties, Cytotoxicity and Cellular Uptake of Organoruthenium(II) Complexes of the Type [(η6‐C6Me6)Ru(L)(pp)]n+ [L = Cl, n = 1; L = (NH2)2CS, n = 2]
Authors: Schäfer Sven , Ott Ingo , Gust Ronald , Sheldrick William S. 
Published: May 2007

AbstractThe DNA binding of polypyridyl (pp) (η6‐hexamethylbenzene)ruthenium(II) complexes of the type [(η6‐C6Me6)RuCl(pp)](CF3SO3) (pp = phen, tap, dpq, dppz, dppn) 1–5 and [(η6‐C6Me6)Ru{(NH2)2CS}(pp)](CF3SO3)2 (pp = dpq, dppz, dppn) 6–8 has been studied by UV/Vis spectroscopy, circular dichroism and viscosity measurements. Complexes 3–5, 7 and 8 are potent cytotoxic agents towards the human cancer cell lines MCF‐7 and HT‐29. Stable intercalative binding into CT DNA is indicated for the dpq and dppz complexes by large increases ΔTm of 12–25 °C in the DNA thermal denaturation temperature for r = [complex]/[DNA] = 0.1. Large viscosity increases for DNA in the presence of 3 and 4 are also in accordance with this binding mode as are the pronounced hypochromic UV/Vis shifts for the π–π* transitions of the dppz ligands of 4 and 7 in the range 360–400 nm. A small ΔTm value of 2 °C and effectively unchanged viscosity suggest that Ru–N (nucleobase) coordinative binding is thermodynamically preferred for the larger polypyridyl ligand of 5 under equilibrium conditions, as is also the case for the small ligands phen and tap in complexes 1 and 2. CD spectra indicate that the B DNA conformation is essentially retained for interaction with the chloro complexes 1–5 but that very significant distortions occur for the thiourea complexes 6–8. The in vitro cytotoxicities of the chloro complexes 3–5 are dependent on the size of the polypyridyl ligand with IC50 values increasing in the order dppn < dppz < dpq: for instance IC50 values of 11.1, 2.12, and 0.13 μM were determined for 3–5 towards MCF‐7. These values correlate well with the cellular uptake efficiency which increases from 1.1 over 146.6 to 906.7 ng(Ru)/mg (protein) within the series 3–5. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Recent Developments in Phosphole‐Containing Oligo‐ and Polythiophene Materials
Authors: Hobbs Matthew G. , Baumgartner Thomas 
Published: May 2007

AbstractThe introduction of phosphorus‐containing moieties into π‐conjugated thiophene materials has been found to provide materials with strongly optimized and highly tunable optoelectronic features compared to their native thiophene counterparts. 2,5‐Diaryl‐ and 2,5‐bis(heteroaryl)phospholes as well as fused tricyclic dithieno[3,2‐b:2′,3′‐d]phospholes represent two very valuable building blocks for organic electronics as their intriguing features can be altered systematically by several, in part unique, methodologies. The potential scope of these modifications has been determined by comprehensive investigations of their structure–property relationships via suitable molecular model compounds. Onseveral occasions, these observations could successfully be transposed to corresponding polymers that are often difficult to characterize independently. The same is true for the first organic light‐emitting diodes (OLEDs) based on a phosphole scaffold, whose properties could also be predicted successfully. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Heptakis[2,3‐di‐O‐methyl‐6‐O‐(L‐valine‐tert‐butylamide‐Nα‐ylcarbonylmethyl)]‐β‐cyclodextrin: a New Multifunctional Cyclodextrin CSA for the NMR Enantiodiscrimination of Polar and Apolar Substrates
Authors: Uccello‐Barretta Gloria , Nazzi Samuele , Balzano Federica , Levkin Pavel A. , Schurig Volker , Salvadori Piero 
Published: May 2007

AbstractHeptakis[2,3‐di‐O‐methyl‐6‐O‐(L‐valine‐tert‐butylamide‐Nα‐ylcarbonylmethyl)]‐β‐cyclodextrin with methyl groups on the secondary sites and a diamide chiral selector on the primary ones showed considerable utility as a CSA in the NMR enantiodiscrimination of a wide spectrum of amino acid derivatives, while also allowing trisubstituted allenes to be enantiodiscriminated. Enantiodiscrimination processes were investigated by Diffusion‐Ordered SpectroscopY (DOSY). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Base‐Catalyzed Anti‐Markovnikov Hydroamination of Vinylarenes – Scope, Limitations and Computational Studies
Authors: Horrillo‐Martínez Patricia , Hultzsch Kai C. , Gil Adrià , Branchadell Vicenç 
Published: May 2007

AbstractThe hydroamination of vinylarenes with primary and secondary amines was studied with catalytic amounts as low as 2 mol‐% of LiN(SiMe3)2/TMEDA. Reactions proceeded readily at 120 °C in the absence of solvent to give selective anti‐Markovnikov addition. Slow addition was observed at 25 °C with either electron‐deficient p‐chlorostyrene or secondary cyclic amines such as pyrrolidine, piperidine, or morpholine. Primary amines were prone to a second hydroamination reaction to form tertiary amine byproducts. The selectivity for the mono(hydroamination) products could be improved with a two‐fold excess of the amine. KN(SiMe3)2 showed higher catalytic activity but lower selectivity in comparison to that of LiN(SiMe3)2, resulting in undesired C–H‐activation byproducts. The mechanism of the lithium‐catalyzed hydroamination and the influence of TMEDA was studied with density functional theory. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Stereoselective Synthesis of Hexahydroisobenzofuran‐4(1H)‐ones from Chiral Substituted Cyclohex‐2‐enyl Carbamates via Asymmetric Homoaldol Reaction and THF Cyclocondensation
Authors: Becker Jochen , Fröhlich Roland , Kataeva Olga , Hoppe Dieter 
Published: May 2007

AbstractThe diastereofacial selectivity of the homoaldol reaction of metalated substituted cyclohex‐2‐enyl carbamates with aldehydes is controlled by the nature of the metal complex. Allyllithiums yield syn‐configured products whereas transmetallation to Ti(NEt2)3 gives access to anti‐configured 3‐(1‐hydroxyalkyl)cyclohexenes. The syn‐configured homoaldol products were transformed into annulated all‐cis‐tetrahydrofurans by Lewis acid‐mediated cyclocondensation with aldehydes. Analogous cis,trans,cis‐substituted hexahydroisobenzofuran‐4(1H)‐ones, the core structure of many biologically active natural products, were synthesized starting from anti‐configured homoaldol products. The configurations of the products were determined by 1H NMR coupling constants, nOe‐studies, and X‐ray crystal structure analysis. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Cover Picture: From Allenes to Tetracenes: A Synthetic and Structural Study of Silyl‐ and Halo‐Allenes and Their Dimers (Eur. J. Org. Chem. 16/2007)
Authors: Banide Emilie V. , Molloy Bevin C. , Ortin Yannick , Müller‐Bunz Helge , McGlinchey Michael J. 
Published: May 2007

AbstractThe cover picture shows the entrance to the World Heritage Site at Newgrange, a 5000‐year‐old Neolithic passage tomb, situated near Dublin. The background depicts a twofold symmetric spiral engraving on the entrance stone and provides an appropriate motif for the sequential transformation of 9‐(trimethylsilylethynyl)‐9H‐fluoren‐9‐ol, via 3,3‐(biphenyl‐2,2′‐diyl)‐1‐(trimethylsilyl)allene, into a series of sterically crowded head‐to‐tail and tail‐to‐tail silyl‐allene dimers with unusually long carbon–carbon and carbon–silicon bonds. Removal of the silyl substituents culminates in the formation of the bis(alkylidene)cyclobutane shown, whose intrinsic C2 symmetry arises solely from the overlap of fluorenylidene fragments with very large wingspans. Details of this work are described in the article by M. J. McGlinchey et al. on p. 2611 ff.
Combined cup loading, bis(2‐hydroxyethyl) disulfide, and protein precipitation protocols to improve the alkaline proteome of Lactobacillus hilgardii
Authors: Lamberti Cristina , Pessione Enrica , Giuffrida Maria G. , Mazzoli Roberto , Barello Cristina , Conti Amedeo , Giunta Carlo 
Published: May 2007

AbstractDespite the large number of papers dealing with bacterial proteomes, very few include information about proteins with alkaline pI's, because of the limits inherent in 2‐DE technology. Nonetheless, analyses of in silico proteomes of many prokaryotes show a bimodal distribution of their proteins based on their pI's; the most crowded areas lying between pI 4–7 and 9–11. The aim of the present research was to set up a general, simple, and standardizable 2‐DE protocol suitable for studying the alkaline proteome of Lactobacillus hilgardii, a Gram‐positive bacillus isolated from wine. The method has also been tested on a Gram‐negative bacterium able to degrade aromatic pollutants, Acinetobacter radioresistens S13. Optimization of the method was mainly focused on improving protein extraction and IEF (pI 6–11) separation protocols. Concerning IEF, different methods for sample loading (in‐gel rehydration and cup loading), and different reducing agents (DTT and bis(2‐hydroxyethyl) disulfide (HED)) were tested and compared. The proposed protocol was found to resolve efficiently alkaline proteins from both of our Lactobacillus and Acinetobacter strains, in spite of their different external layers, thus, enabling a more comprehensive study of their proteomes.
Genome‐wide array‐based comparative genomic hybridization of ocular marginal zone B cell lymphoma: Comparison with pulmonary and nodal marginal zone B cell lymphoma
Authors: Kim Won Seog , Honma Keiichiro , Karnan Sivasundaram , Tagawa Hiroyuki , Kim Yoon Duck , Oh Young Lyun , Seto Masao , Ko Young Hyeh 
Published: May 2007

AbstractThe genetic changes in marginal zone B cell lymphomas (MZBCL) vary according to the anatomical region. This study aimed to investigate genomic aberrations in ocular MZBCL and to compare them with those of tumors from other anatomical sites. The study population comprised 24 cases of primary ocular MZBCL, 11 pulmonary MZBCL, and seven nodal MZBCL. For array CGH, fresh tumor tissues were analyzed with a genome‐wide scanning array containing 2,304 BAC/PAC clones which cover the whole human genome at a resolution of 1.3 Mb. FISH analysis for MALT1 gene alteration was performed for ocular and nodal MZBCL and RT‐PCR for the detection of API2‐MALT1 transcripts was performed for pulmonary MZBCL. The recurrent genomic alterations in ocular MZBCL were losses of chromosome bands 6q23.3 (9/24, 38%), 7q36.3 (2/24, 8%), and 13q34 (2/24, 8%), and gains of chromosomes 3 (9/24, 38%), and 15 (4/24, 16%), and chromosome arms 18q (4/24, 16%), and 6p (2/24, 8%). The t(11;18)(q21;q21) was not detected. The genomic alterations of pulmonary MZBCL included recurrent loss of 18q21 (2/11, 19%). A t(11;18)(q21;q21) fusion transcript was detected in five out of eight cases (63%). Nodal MZBCL showed neither recurrent genome alterations nor any change in MALT1 gene copy number. In conclusion, the array CGH profile of ocular MZBCL is distinct from those of pulmonary and nodal MZBCL. Deletion of chromosome band 6q23.3 in ocular MZBCL is a novel finding and may constitute a crucial genetic alteration in the pathogenesis of ocular MZBCL. © 2007 Wiley‐Liss, Inc.