bluuebunny/crossref_metadata_2025_split huggingface dataset:
Patterns of obsessive compulsive symptoms in tourette subjects are independent of severity
Authors: de Groot Christopher M. , Bornstein Robert A. , Janus Mark‐David , Mavissakalian Matig R. 
Published: November 2013

AbstractStudies have examined the expression of obsessive compulsive (OC) symptoms in obsessive compulsive disorder (OCD), OCD with co‐occurring Tourette's Syndrome (TS) or chronic motor tic disorder (CMT) and TS alone. In adult samples, there appears to be a relatively consistent OC symptom thematic content that characterizes OCD alone and OCD in conjunction with tics or TS. Previous studies have controlled for the severity of OC symptoms in OCD and TS groups. In the current study, it was our objective to determine whether patterns of OC symptoms in TS are independent of OC symptom severity.The current exploratory study examined OC symptom expression in a nonclinically based TS sample with a broad range of OC symptoms and severity and a selected clinical OCD sample without TS/tics. Univariate and multivariate statistical analysis explored patterns of OC symptom expression between the two groups.Similar to previous reports examining OC symptoms in OCD and OCD with TS/tics, subjects with OCD alone were characterized by contamination obsessions and cleaning compulsions. In contrast, TS subjects had more somatic, sexual and symmetry obsessions and more checking, counting and touching/blinking compulsions, independent of OC symptom and tic severity. A discriminant function using obsessive items alone correctly grouped 91.4% of cases.The current study replicates patterns of OC symptom expression unique to OCD alone. Patterns of OC symptoms, in particular obsessive symptoms, can robustly predict membership in OCD or TS groups, even with a substantial variation in OC symptom severity as measured by the Y‐BOCS score. Anxiety 1:268–274 (1994/1995). © 1995 Wiley‐Liss, Inc.
Development Impacts of Seasonal and Temporary Migration: A Review of Evidence from the Pacific and Southeast Asia
Authors: Gibson John , McKenzie David , Rohorua Halahingano 
Published: November 2013

AbstractSeasonal and temporary migration programs are widely used around the world, yet there is scant evidence as to their development impacts. Absent such evidence, it is difficult to evaluate whether the proliferation of temporary worker programs in recent years is a useful development. This article reviews studies that attempt to measure impacts of seasonal and temporary migration with a particular focus on evidence from the Pacific and Southeast Asia.
Formation of Periodic γ‐Turns in α/β‐Hybrid Peptides: DFT and NMR Experimental Evidence
Authors: Chandrasekhar Srivari , Rao Kakita Veera Mohana , Seenaiah Mallikanti , Naresh Police , Devi Ambure Sharada , Jagadeesh Bharatam 
Published: November 2013

AbstractHybrid peptidic oligomers comprising natural and unnatural amino acid residues that can exhibit biomolecular folding and hydrogen‐bonding mimicry have attracted considerable interest in recent years. While a variety of hybrid peptidic helices have been reported in the literature, other secondary structural patterns such as γ‐turns and ribbons have not been well explored so far. The present work reports the design of novel periodic γ‐turns in the oligomers of 1:1 natural‐α/unnatural trans‐β‐norborenene (TNAA) amino acid residues. Through DFT, NMR, and MD studies, it is convincingly shown that, in the mixed conformational pool, the heterogeneous backbone of the hybrid peptides preferentially adopt periodic 8‐membered (pseudo γ‐turn)/7‐membered (inverse γ‐turn) hydrogen bonds in both polar and non‐polar solvent media. It is observed that the stereochemistry and local conformational preference of the β‐amino acid building blocks have a profound influence on accessing the specific secondary fold. These findings may be of significant relevance for the development of molecular scaffolds that facilitate desired positioning of functional side‐chains.
Synthesis and In Vitro Photodynamic Activities of an Integrin‐Targeting cRGD‐Conjugated Zinc(II) Phthalocyanine
Authors: Ke Mei‐Rong , Ng Dennis K. P. , Lo Pui‐Chi 
Published: November 2013

AbstractA 1,4‐disubstituted zinc(II) phthalocyanine conjugated with a cyclic Arg‐Gly‐Asp‐D‐Phe‐Lys (cRGDfK) moiety through a triazole linker was prepared and characterized by UV/Vis spectroscopy and high‐resolution ESI‐MS. The conjugate showed a relatively weak fluorescence emission in N,N‐dimethylformamide (ΦF=0.08), but it was a very efficient singlet oxygen generator (ΦΔ=0.80) as a result of the di‐α‐substituted structure. Owing to the presence of the cyclic peptide sequence cRGDfK, which is a well‐known αvβ3‐integrin antagonist, this conjugate exhibited significantly higher cellular uptake toward the αvβ3+ U87‐MG cells compared with the αvβ3− MCF‐7 cells, as determined by flow cytometry and fluorescence microscopy. The photocytotoxicity of this compound against these two cell lines, however, was comparable owing to the similar efficiency of intracellular reactive oxygen species generation. Confocal microscopic studies also revealed that this conjugate localized preferentially in the lysosomes, but not in the nucleus, endoplasmic reticulum, and mitochondria of the U87‐MG cells.
Palladium‐Catalyzed Regio‐ and Stereoselective Chlorothiolation of Terminal Alkynes with Sulfenyl Chlorides
Authors: Iwasaki Masayuki , Fujii Tomoya , Yamamoto Arisa , Nakajima Kiyohiko , Nishihara Yasushi 
Published: November 2013

AbstractChlorothiolation of terminal alkynes with sulfenyl chlorides yields anti‐adducts without transition‐metal catalysts. In sharp contrast, transition‐metal‐catalyzed chlorothiolation has not been developed to date, possibly because organosulfur compounds can poison catalyst. Herein, the regio‐ and stereoselective palladium‐catalyzed chlorothiolation of terminal alkynes with sulfenyl chlorides is described. syn‐Chlorothiolation offers a complementary synthetic route to chloroalkenyl sulfides. 2‐Chloroalkenyl sulfides can easily be transformed into various sulfur‐containing products, most of which are often found in natural products and pharmaceuticals.
Berberine induces apoptosis in human multiple myeloma cell line U266 through hypomethylation of p53 promoter
Authors: Qing Yanwei , Hu Haiyan , Liu Yuan , Feng Tao , Meng Wei , Jiang Ling , Sun Yongning , Yao Yang 
Published: November 2013

AbstractBerberine has multiple pharmacological activities, such as anti‐oxidative, anti‐inflammation and anticancer activity. It reduces the proliferation and induces apoptosis in the multiple myeloma cell line, U266. Here we explored the detailed mechanism by analysing the gene expression profiles in U266 treated with or without berberine. DNMT1 and DNMT3B, encoding for a highly conserved member of the DNA methyltransferases, decreased significantly. By dissection of biochemical network database (BNDB) with Kyoto Encyclopaedia of Genes and Genomes (KEGG) annotation, the p53 signalling pathway related genes were altered. By using epigenetic chromatin modification enzymes PCR Array, gene expression microarray, RT‐PCR and Bisulphite sequencing, the results show that berberine can repress the expression of DNMT1 and DNMT3B, which triggers hypomethylation of TP53 by changing the DNA methylation level and the alteration of p53 dependent signal pathway in human multiple melanoma cell U266.
Direct Synthesis of Ruthenium‐Containing Ordered Mesoporous Carbon with Tunable Embedding Degrees by Using a Boric Acid‐Assisted Approach
Authors: Lan Guojun , Tang Haodong , Zhou Yaping , Han Wenfeng , Liu Huazhang , Li Xiaonian , Li Ying 
Published: November 2013

AbstractUniform ruthenium nanoparticles (1–2 nm) confined in ordered mesoporous carbon (Ru‐OMC) with various embedding degrees have been fabricated by using a boric acid‐assisted hard template method. The catalytic performance of Ru‐OMC catalysts was determined through the hydrogenation of toluene at 110 °C and 4.0 MPa. The effects of pore size and embedding degree on the catalytic performance were studied and compared with those of OMC‐supported ruthenium (Ru/OMC) catalysts with various pore sizes. The catalytic activities of embedding Ru‐OMC catalysts are much higher than those of supported Ru/OMC catalysts, which can be attributed to the strong interaction between ruthenium nanoparticles and the carbon support. Furthermore, the activities of Ru‐OMC catalysts are closely related to the embedding degree of ruthenium nanoparticles in the carbon matrix. The Ru‐OMC catalysts with an appropriate embedding degree affords a turnover frequency of up to 4.69 s−1 in toluene hydrogenation.
Rare‐Earth‐Doped Pt/Ba/Ce0.6Zr0.4O2‐Al2O3 for NOx Storage and Reduction: The Effect of Rare‐Earth Doping on Efficiency and Stability
Authors: Wang Xiuyun , Chen Zhilin , Wang Yuling , Wang Ruihu 
Published: November 2013

AbstractRare‐earth‐doped Pt/Ba/RO‐CZA (RO=La2O3, Nd2O3 and Y2O3; CZA=Ce0.6Zr0.4O2‐Al2O3) were synthesized and characterized by XRD, N2 physisorption, Raman spectroscopy, H2 temperature‐programmed reduction, extended X‐ray absorption fine structure analysis, scanning transmission electron microscopy, and X‐ray photoelectron spectroscopy. The effect of the addition of rare earths on Pt/Ba/RO‐CZA was explored, and the relationship between their structures and properties was disclosed. In comparison with Pt/Ba/CZA, La and Nd addition, especially La addition, resulted in an apparent increment of oxygen vacancies and the improvement of the reductive capacity of Ce4+, which are favorable for NOx reduction. However, the presence of Y induced a negative effect on NOx storage and reduction (NSR). The NSR performances of Pt/Ba/RO‐CZA were initially evaluated by using NO‐to‐NO2 conversion, NOx storage capacity, and NOx conversion. The NOx conversion in Pt/Ba/La‐CZA and Pt/Ba/Nd‐CZA at 350 °C is up to 98 and 94 %, respectively. Interestingly, the addition of rare earths contributes to the enhancement of the thermal stability, a slight decrement of NOx conversion was observed after Pt/Ba/RO‐CZA were maintained at 350 °C for 100 h, whereas an obvious loss of catalytic activity was found in Pt/Ba/CZA under the same conditions. TEM analysis showed that the presence of La inhibits the agglomeration of Pt and the sintering of particles.
New Calcium‐Selective Smart Contrast Agents for Magnetic Resonance Imaging
Authors: Verma Kirti Dhingra , Forgács Attila , Uh Hyounsoo , Beyerlein Michael , Maier Martin E. , Petoud Stéphane , Botta Mauro , Logothetis Nikos K. 
Published: November 2013

AbstractCalcium plays a vital role in the human body and especially in the central nervous system. Precise maintenance of Ca2+ levels is very crucial for normal cell physiology and health. The deregulation of calcium homeostasis can lead to neuronal cell death and brain damage. To study this functional role played by Ca2+ in the brain noninvasively by using magnetic resonance imaging, we have synthesized a new set of Ca2+‐sensitive smart contrast agents (CAs). The agents were found to be highly selective to Ca2+ in the presence of other competitive anions and cations in buffer and in physiological fluids. The structure of CAs comprises Gd3+‐DO3A (DO3A=1,4,7‐tris(carboxymethyl)‐1,4,7,10‐tetraazacyclododecane) coupled to a Ca2+ chelator o‐amino phenol‐N,N,O‐triacetate (APTRA). The agents are designed to sense Ca2+ present in extracellular fluid of the brain where its concentration is relatively high, that is, 1.2–0.8 mM. The determined dissociation constant of the CAs to Ca2+ falls in the range required to sense and report changes in extracellular Ca2+ levels followed by an increase in neural activity. In buffer, with the addition of Ca2+ the increase in relaxivity ranged from 100–157 %, the highest ever known for any T1‐based Ca2+‐sensitive smart CA. The CAs were analyzed extensively by the measurement of luminescence lifetime measurement on Tb3+ analogues, nuclear magnetic relaxation dispersion (NMRD), and 17O NMR transverse relaxation and shift experiments. The results obtained confirmed that the large relaxivity enhancement observed upon Ca2+ addition is due to the increase of the hydration state of the complexes together with the slowing down of the molecular rotation and the retention of a significant contribution of the water molecules of the second sphere of hydration.
4‐Trifluoromethyl‐Substituted Coumarins with Large Stokes Shifts: Synthesis, Bioconjugates, and Their Use in Super‐Resolution Fluorescence Microscopy
Authors: Schill Heiko , Nizamov Shamil , Bottanelli Francesca , Bierwagen Jakob , Belov Vladimir N. , Hell Stefan W. 
Published: November 2013

AbstractBright and photostable fluorescent dyes with large Stokes shifts are widely used as sensors, molecular probes, and light‐emitting markers in chemistry, life sciences, and optical microscopy. In this study, new 7‐dialkylamino‐4‐trifluoromethylcoumarins have been designed for use in bioconjugation reactions and optical microscopy. Their synthesis was based on the Stille reaction of 3‐chloro‐4‐trifluoromethylcoumarins and available (hetero)aryl‐ or (hetero)arylethenyltin derivatives. Alternatively, the acylation of 2‐trifluoroacetyl‐5‐dialkylaminophenols with available (hetero)aryl‐ or (hetero)arylethenylacetic acids followed by intramolecular condensation afforded coumarins with 3‐(hetero)aryl or 3‐[2‐(hetero)aryl]ethenyl groups. Hydrophilic properties were provided by the introduction of a sulfonic acid residue or by phosphorylation of a primary hydroxy group attached at C‐4 of the 2,2,4‐trimethyl‐1,2‐dihydroquinoline fragment fused to the coumarin fluorophore. For use in immunolabeling procedures, the dyes were decorated with an (activated) carboxy group. The positions of the absorption and emission maxima vary in the ranges 413–480 and 527–668 nm, respectively. The phosphorylated dye, 9,CHCH‐2‐py,H, with the 1‐(3‐carboxypropyl)‐4‐hydroxymethyl‐2,2‐dimethyl‐1,2‐dihydroquinoline fragment fused to the coumarin fluorophore bearing the 3‐[2‐(2‐pyridyl)ethenyl] residue (absorption and emission maxima at 472 and 623 nm, respectively) was used in super‐resolution light microscopy with stimulated emission depletion and provided an optical resolution better than 70 nm with a low background signal. As a result of their large Stokes shifts, good fluorescence quantum yields, and adequate photostabilities, phosphorylated coumarins enable two‐color imaging (using several excitation sources and a single depletion laser) to be combined with subdiffractional optical resolution.
Bioconjugation of Proteins with a Paramagnetic NMR and Fluorescent Tag
Authors: Huang Feng , Pei Ying‐Ying , Zuo Hui‐Hui , Chen Jia‐Liang , Yang Yin , Su Xun‐Cheng 
Published: November 2013

AbstractSite‐specific labeling of proteins with lanthanide ions offers great opportunities for investigating the structure, function, and dynamics of proteins by virtue of the unique properties of lanthanides. Lanthanide‐tagged proteins can be studied by NMR, X‐ray, fluorescence, and EPR spectroscopy. However, the rigidity of a lanthanide tag in labeling of proteins plays a key role in the determination of protein structures and interactions. Pseudocontact shift (PCS) and paramagnetic relaxation enhancement (PRE) are valuable long‐range structure restraints in structural‐biology NMR spectroscopy. Generation of these paramagnetic restraints generally relies on site‐specific tagging of the target proteins with paramagnetic species. To avoid nonspecific interaction between the target protein and paramagnetic tag and achieve reliable paramagnetic effects, the rigidity, stability, and size of lanthanide tag is highly important in paramagnetic labeling of proteins. Here 4′‐mercapto‐2,2′: 6′,2′′‐terpyridine‐6,6′′‐dicarboxylic acid (4MTDA) is introduced as a a rigid paramagnetic and fluorescent tag which can be site‐specifically attached to a protein by formation of a disulfide bond. 4MTDA can be readily immobilized by coordination of the protein side chain to the lanthanide ion. Large PCSs and RDCs were observed for 4MTDA‐tagged proteins in complexes with paramagnetic lanthanide ions. At an excitation wavelength of 340 nm, the complex formed by protein–4MTDA and Tb3+ produces high fluorescence with the main emission at 545 nm. These interesting features of 4MTDA make it a very promising tag that can be exploited in NMR, fluorescence, and EPR spectroscopic studies on protein structure, interaction, and dynamics.
Structure and Biosynthesis of Xenoamicins from Entomopathogenic Xenorhabdus
Authors: Zhou Qiuqin , Grundmann Florian , Kaiser Marcel , Schiell Matthias , Gaudriault Sophie , Batzer Andreas , Kurz Michael , Bode Helge B. 
Published: November 2013

AbstractDuring the search for novel natural products from entomopathogenic Xenorhabdus doucetiae DSM17909 and X. mauleonii DSM17908 novel peptides named xenoamicins were identified in addition to the already known antibiotics xenocoumacin and xenorhabdin. Xenoamicins are acylated tridecadepsipeptides consisting of mainly hydrophobic amino acids. The main derivative xenoamicin A (1) was isolated from X. mauleonii DSM17908, and its structure elucidated by detailed 1 D and 2 D NMR experiments. Detailed MS experiments, also in combination with labeling experiments, confirmed the determined structure and allowed structure elucidation of additional derivatives. Moreover, the xenoamicin biosynthesis gene cluster was identified and analyzed in X. doucetiae DSM17909, and its participation in xenoamicin biosynthesis was confirmed by mutagenesis. Advanced Marfey’s analysis of 1 showed that the absolute configuration of the amino acids is in agreement with the predicted stereochemistry deduced from the nonribosomal peptide synthetase XabABCD. Biological testing revealed activity of 1 against Plasmodium falciparum and other neglected tropical diseases but no antibacterial activity.
Synthesis, Characterization, and Thermal Behavior of Carboranyl–Styrene Decorated Octasilsesquioxanes: Influence of the Carborane Clusters on Photoluminescence
Authors: Ferrer‐Ugalde Albert , Juárez‐Pérez Emilio José , Teixidor Francesc , Viñas Clara , Núñez Rosario 
Published: November 2013

AbstractNovel polyhedral oligomeric silsesquioxanes (POSS) or octasilsesquioxanes with carboranyl–styrene fragments attached to each corner are described. These compounds have been synthesized by olefin‐metathesis reactions between octavinylsilsesquioxane and carboranyl–styrene compounds that possess different substituents (Ph, Me, or H). In all cases, these reactions, which were catalyzed by the Grubbs catalyst, are highly regioselective and yield exclusively the E isomers. The existence of the carborane cage in the POSS structure induces a remarkable thermal stability in these compounds. After combustion at 1000 °C, these carboranyl–POSS compounds exhibit a mass loss lower than 10 %. The UV/Vis absorption data of these carboranyl–POSS compounds shows a slight bathochromic shift with respect to the carboranyl–styrene monomers, with an absorption maximum around 262 nm. Nevertheless, important differences in the emission spectra of the carboranyl–POSS compounds with regard to their carboranyl–styrene precursors are observed; the phenyl‐o‐carborane‐containing POSS compound exhibits the highest fluorescence intensity (ΦF=44 %), whereas for the POSS compound bearing the methyl substituent, and for the unsubstituted o‐carborane clusters, the fluorescence intensity is much lower (ΦF=9 and 2 %, respectively). This is precisely the reverse of what occurs with the monomers, in which the unsubstituted o‐carboranyl–styrene compound exhibits the highest ΦF, and a quenching of the fluorescence is observed in the phenyl‐o‐carboranyl–styrene compound. In addition, a large red shift of around 100 nm is observed for the POSS compounds with respect to their precursors. These experimental results can only be accounted for by the spatial ordering induced by the POSS core that eases interactions, which otherwise would not occur. These results have been confirmed by time‐dependent density functional theory (TDDFT) calculations that exclude a photoinduced electron transfer (PET) process in the POSS compounds.
Increasing the Bioavailability of RuIIIAnticancer Complexes through Hydrophobic Albumin Interactions
Authors: Webb Michael I. , Wu Boris , Jang Thalia , Chard Ryan A. , Wong Edwin W. Y. , Wong May Q. , Yapp Donald T. T. , Walsby Charles J. 
Published: November 2013

AbstractA series of pyridine‐based derivatives of the clinically successful RuIII‐based complexes indazolium [trans‐RuCl4(1 H‐indazole)2] (KP1019) and sodium [trans‐RuCl4(1 H‐indazole)2] (KP1339) have been synthesized to probe the effect of hydrophobic interactions with human serum albumin (hsA) on anticancer activity. The solution behavior and protein interactions of the new compounds were characterized by using electron paramagnetic resonance (EPR) and UV/Vis spectroscopy. These studies have revealed that incorporation of hydrophobic substituents at the 4′‐position of the axial pyridine ligand stabilizes non‐coordinate interactions with hsA. As a consequence, direct coordination to the protein is inhibited, which is expected to increase the bioavailability of the complexes, thus potentially leading to improved anticancer activity. By using this approach, the lifetimes of hydrophobic protein interactions were extended from 2 h for the unsubstituted pyridine complex, to more than 24 h for several derivatives. Free complexes were tested for their anticancer activity against the SW480 human colon carcinoma cell line, exhibiting low cytotoxicity. Pre‐treatment with hsA improved the solubility of every compound and led to some changes in activity. Particularly notable was the difference in activity between the methyl‐ and dibenzyl‐functionalized complexes. The former shows reduced activity after incubation with hsA, indicating reduced bioavailability due to protein coordination. The latter exhibits little activity on its own but, following treatment with hsA, exhibited significant cytotoxicity, which is consistent with its ability to form non‐coordinate interactions with the protein. Overall, our studies demonstrate that non‐coordinate interactions with hsA are a viable target for enhancing the activity of RuIII‐based complexes in vivo.
Fluorescence Modulation in Tribranched Switchable [4]Rotaxanes
Authors: Zhang Ji‐Na , Li Hong , Zhou Wei , Yu Shi‐Lin , Qu Da‐Hui , Tian He 
Published: November 2013

AbstractTwo novel tribranched [4]rotaxanes with a 1,3,5‐triphenylene core and three rotaxane arms have been designed, synthesized, and characterized by 1H and 13C NMR spectroscopies and HR‐ESI mass spectrometry. [4]Rotaxanes 1 and 2 each possess the same three‐armed skeleton. Each arm incorporates two distinguishable binding sites for a dibenzo[24]crown‐8 ring, namely a dibenzylammonium site and an N‐methyltriazolium site, and is terminated by a 4‐morpholino‐naphthalimide fluorophore as a stopper. [4]Rotaxane 1 has three di‐ferrocene‐functionalized dibenzo[24]crown‐8 rings whereas 2 has three simple dibenzo[24]crown‐8 rings interlocked with the thread component. Uniform shuttling motions of the three macrocycles in both 1 and 2 can be driven by external acid–base stimuli, which were confirmed by 1H NMR spectroscopy. However, [4]rotaxanes 1 and 2 show distinct modes of fluorescence modulation in response to external acid–base stimuli. [4]Rotaxane 1 exhibits a remarkable fluorescence decrease in response to the addition of 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) as a base, which can displace the ferrocene‐functionalized macrocycle from the dibenzylammonium station to the N‐methyltriazolium station. In contrast, the fluorescence intensity of [4]rotaxane 2 showed an enhancement with the addition of DBU. Time‐resolved fluorescence measurements have been performed. The different photoinduced electron‐transfer processes responsible for the fluorescence changes in the two molecular systems are discussed. Topological structures of this kind have significant potential for the design and construction of large and complex assemblies with controllable functions.