bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization, Crystal Structure and Initial DNA Binding Interaction of Two Cu(II) Complexes with 4,5‐Diazafluoren‐9‐one
Authors: SONG Yan‐Hong , ZHANG Rong‐Lan , SUN Qing‐Jin , XU Zhan‐Wei , GAO Quan‐Chang , LIU Hua‐Qiang , ZHAO Jian‐She 
Published: October 2007

AbstractTwo new complexes [Cu(dafo)2(en)](ClO4)2·2H2O (en=NH2CH2CH2NH2) 1 and [Cu(dafo)2(dap)](ClO4)2· 2H2O [dap=NH2CH2CH(CH3)NH2] 2 (dafo=4,5‐diazafluoren‐9‐one) have been synthesized and characterized by elemental analysis, IR and UV spectra. Meanwhile, the complex 1 has been characterized by single crystal X‐ray diffraction analysis. The initial DNA binding interactions of the complexes 1 and 2 have been investigated by UV spectra, emission spectra and cyclic voltammogram. Concluding the results of three methods used to measure the interaction of complexes 1 and 2 with DNA, the action mode of the two complexes with DNA is intercalation, and character of ligands and steric effect may affect the interaction of the complexes with DNA.
Effect of Variant Counterions on Stability and Particle Size of Silica Sol
Authors: PAN Ming‐Chu , YANG Yu‐Xiang , YING Hai‐Ping , JIA Xiang‐Chen , CHEN Ya‐Ru , TANG Yue 
Published: October 2007

AbstractThe effects of variant counterions with ionic strength of 0.05, 0.10, 0.20 and 0.25 mol·kg−1 on the stability and particle size of silica sols have been studied using the traditional methods of Ubbelohde viscosity measurement, TEM and titration respectively, finding that the stability and particle size of the silica sols are all concerned with the acidic, positively electric properties and the sizes of the counterions, as well as the attraction between the counterions and surface silicon hydroxyl groups of the silica sols. The small positively charged counterions lead to the decrease in particle sizes, making the silica sol the most stable. But the larger weakly acidic counterions can restrict the particle sizes of the silica sols and easily make the sols coagulate. It was also found that there existed a linear relationship between log r and log η, which has not ever been reported. The effect of temperature on the stability and particle sizes was also discussed.
A Sensitive Derivatization Method for the Determination of the Sugar Composition after Pre‐column Reductive Amination with 3‐Amino‐9‐ethylcarbazole (AEC) by High‐Performance Liquid Chromatography
Authors: ZHANG Ying , HUANG Lin‐Juan , WANG Zhong‐Fu 
Published: October 2007

Abstract3‐Amino‐9‐ethylcarbazole (AEC) was employed for monosaccharide derivatization. The derivatives can be analyzed by high‐performance liquid chromatography (HPLC) with an ultraviolet detection (wavelength: 254 nm). Monosaccharides were quantitatively derivatized with 3‐amino‐9‐ethylcarbazole (AEC) at 70 °C for 60 min. The method was linear for all samples over the concentration range tested (r>0.999), the precision was found to be satisfactory (R.S.D.<3%), and the recovery ratios were >98.62%. The stability analysis showed R.S.D. was between 1.81% –3.16%. Detection limits for the samples (D‐glucose, L‐xylose, D‐mannose, L‐arabinose, and L‐rhamnose) ranged from 0.06 to 1.97 ng/mL (S/N=3). Under the optimized derivatization and HPLC conditions, five monosaccharides were well separated using a narrow bore C18 column (250 mm×4.6 mm) with 0.1 mol/L ammonium acetate containing 25% acetonitrile at a flow rate of 0.5 mL/min. As an application, the method has been successfully applied to the determination of monosaccharide compositions of three polysaccharides SPPA‐1, SPPB‐1 and SPPC‐1 of Spirulina platensis. This method also has potential application to oligosaccharide or glycan analyses.
Selective Electrochemical Recognition ofo‐Phenylenediol by a Novel Calix[4]arene Derivative
Authors: LÜ Jian‐Quan , ZHANG Hai‐Li , LU Ping 
Published: October 2007

AbstractA new type of calixarene‐modified electrode has been prepared by directly coating the surface of a glassy carbon electrode with tetrahydrofuran solution containing 25,26,27,28‐tetra‐(3‐amidino thiopropoxy)‐5,11,17,23‐tetra‐tert‐butylcalix[4]arene, and applied to the investigation of electrochemical behavior of phenylenediols. The results showed that the modified electrode could selectively recognizeo‐phenylenediol, making the over‐potential ofo‐phenylenediol dropped and peak current increased greatly. The anodic peak current is proportional to the concentration ofo‐phenylenediol in the range of 1.0×10−5–1.0×10−4mol·L−1with the detection limit (S/N=3) of 1.0×10−7mol·L−1. The recognizing mechanism, including electrochemical process and binging sites, was also discussed using voltammetry.
Hydrolysis Reaction of N‐Phosphoryl‐α‐, β‐ and γ‐amino Acids Studied by HPLC
Authors: QIANG Li‐Ming , CAO Shu‐Xia , ZHAO Xiao‐Yang , LIU Ruo‐Yu , LIU Ji‐Hong , LU Jian‐Sha , ZHAO Yu‐Fen 
Published: October 2007

AbstractThe hydrolysis reactions of N‐(O,O′‐diisopropyl)phosphoryl‐L‐α‐alanine (DIPP‐L‐α‐Ala), N‐(O,O′‐diisopropyl)‐ phosphoryl‐D‐α‐alanine (DIPP‐D‐α‐Ala), N‐(O,O′‐diisopropyl)phosphoryl‐β‐alanine (DIPP‐β‐Ala) and N‐(O,O′‐ diisopropyl)phosphoryl‐γ‐amino butyric acid (DIPP‐γ‐Aba), were studied by HPLC and their hydrolysis reaction kinetic equations were obtained. Under acid conditions, the reaction rate of DIPP‐L‐α‐Ala was close to that of DIPP‐D‐α‐Ala and the same rule was true between DIPP‐β‐Ala and DIPP‐γ‐Aba. Meantime, the reaction rate of DIPP‐L/D‐α‐Ala was as 10 times as that of DIPP‐β‐Ala or DIPP‐γ‐Aba. Under basic conditions, the hydrolysis reactions of DIPP‐β‐Ala and DIPP‐γ‐Aba almost did not take place and the reaction rate of DIPP‐L/D‐α‐Ala was about 1/10 of that under acid conditions. Moreover, theoretical calculation further illuminated the differences of the hydrolysis rate from the view of energy. The results would provide some helpful clues to why nature chose α‐amino acids but not other kinds of analogs as protein backbones.
Synthesis and Biological Activities of Substituted Triazolethione Schiff Base
Authors: SUN Xiao‐Hong , TAO Yan , LIU Yuan‐Fa , CHEN Bang 
Published: October 2007

AbstractSix novel Schiff bases have been synthesized by the condensation reaction of 4‐amino‐5‐(4‐pyridyl)‐2,4‐dihy‐ dro‐1,2,4‐triazole‐3‐thione with various benzaldehydes. The structures of the compounds have been confirmed by 1H NMR, IR and elemental analysis. The preliminary bioassay indicated that the title compounds possessed good fungicidal activities to several vegetable pathogens.
Electrochemical Reduction of 1,2‐Di(p‐tolylimino)ethane and 1,2‐Di(2,4‐dimethylphenylimino)ethane in Dimethylformamide
Authors: FOTOUHI Lida , ZEIENALI Mahbobeh , DEHGHANPOUR Saeed , NEMATOLLAHI Davood 
Published: October 2007

Abstract1,2‐Di(p‐tolylimino)ethane (I) and 1,2‐Di(2,4‐dimethylphenylimino)ethane (II) were synthesized and their electrochemical behavior investigated in dimethylformamide using classical voltammetry, differential pulse voltammetry, cyclic voltammetry, chronoamperometry, controlled potential electrolysis and coulometry. Both bis‐Schiff base ligands examined show a cathodic irreversible peak which corresponds to one‐electron reduction of the substrate to form anion radical. According to the fact obtained from cyclic voltammetry, that the current function (ip/ù1/2) is a decreasing function of the scan rate, it can be concluded that there is a following coupling chemical reaction (EC mechanism). Thus, the most probable mechanism of electroreduction of both ligands is the coupling of two radicals to form a dimer.
Metallotricycle of Lanthanide Supported by a Bridging Diamide: Syntheses and Molecular Structures of {Li(THF)3[LnCl(μ2‐trans‐1,2‐(NSiMe3)2C6H10)(μ2‐Cl)]}2·2THF (Ln=Yb, Nd)
Authors: LU Cheng‐Rong , LI Hong‐Hai , ZHAO Bei , SHEN Qi , YAO Ying‐Ming , ZHANG Yong 
Published: October 2007

AbstractThe reactions of dilithium salt of trans‐1,2‐bis(trimethylsilylamino)cyclohexane with anhydrous lanthanide trichlorides LnCl3 (Ln=Yb, Nd) in THF afforded the dianionic binuclear tricycles of lanthanide chlorides {Li(THF)3[LnCl(µ2‐trans‐1,2‐(NSiMe3)2C6H10)((2‐Cl)]}2·2THF (Ln=Yb 1, Nd 2) in moderate yields. Both of the bridged complexes were characterized by elemental analysis, IR spectroscopy and single‐crystal X‐ray diffraction. Crystal structural analysis shows that the two complexes are the analogues which have a tricyclic framework built by two bridged lanthanide metals, four nitrogens and four carbons from two diamide ligands. Each lanthanide metal coordinates to three nitrogen atoms and two chlorines to form a distorted trigonal bipyramid and connects with a lithium by a bridging chlorine.
Chiral Salicyl Diamines: Potent Anticancer Molecules
Authors: Gao Jian , Liu Ya‐Guang , Zhou Yaqing , Zingaro Ralph A. 
Published: October 2007

AbstractA set of 12 enantiomeric diamine‐based small molecules was synthesized and screened for anticancer activity against five human cancer cell lines: NCI‐H460, A549, MCF‐7, SK‐BR‐3, and T‐47D. The salicyl diamino compounds (1–6) were found to induce inhibition of the growth of cancer cells at submicromolar concentrations. The lead compound, N,N′‐bis‐salicyl‐(1R,2R)‐diaminocyclohexane (1) displayed single‐reagent anticancer activity with an IC50 value equal to or less than 2.0 μM in H460 and A‐549 cancer cells. SRB and colony formation assays indicated that compound 1 shows greater cytotoxic activity toward MCF‐7 cells than MCF‐10A cells. Real‐time RT‐PCR analysis demonstrated that compound 1, is an extremely efficient regulator of antiapoptotic genes, Bcl‐xL, Bcl‐2, and the cell cycle related gene, cyclin D1. This study provides a new insight into the development of novel small molecules in the treatment of human breast cancers.
Stereochemical and Steric Control of the UDP‐Glucuronosyltransferase‐Catalyzed Conjugation Reaction: A Rational Approach for the Design of Inhibitors for the Human UGT2B7
Authors: Bichlmaier Ingo , Finel Moshe , Sippl Wolfgang , Yli‐Kauhaluoma Jari 
Published: October 2007

AbstractA set of 76 derivatives of the epimeric tricyclic sesquiterpenols longifolol and isolongifolol was subjected to inhibition and glucuronidation assays employing the human UDP‐glucuronosyltransferase (UGT) 2B7. Detailed structure–activity relationships (SARs) with respect to functionality, stereochemical properties, and steric features were derived. To gain further insight into the SARs of UGT2B7 ligands herein, we have developed a 3D‐quantitative structure–activity relationship (3D‐QSAR) using Comparative Molecular Similarity Analysis (CoMSIA). The formation of the enzyme–inhibitor complex was predominantly controlled by spatially directed hydrophobic interactions. The glucuronidation rate was significantly influenced by the steric demand of substituents in proximity of the nucleophilic hydroxy group. The glucuronidation of the compounds was prevented by the introduction of bulky substituents such as isopropyl, tert‐butyl, and phenyl groups. The epimeric longifolol derivatives of series D were the best inhibitors displaying IC50 values as low as 4.6 nM. This study shows that high‐potency substrates can be turned into potent inhibitors by addressing functional, stereochemical, and steric properties.
Dendritic PARACEST contrast agents for magnetic resonance imaging
Authors: Pikkemaat J.A. , Wegh R.T. , Lamerichs R. , van de Molengraaf R.A. , Langereis S. , Burdinski D. , Raymond A.Y.F. , Janssen H.M. , de Waal B.F.M. , Willard N.P. , Meijer E.W. , Grüll H. 
Published: October 2007

AbstractMRI contrast agents based on chemical exchange‐dependent saturation transfer (CEST), such as Yb(III)DOTAM complexes, are highly suitable for pH mapping. In this paper, the synthesis of Yb(III)DOTAM‐functionalized poly(propylene imine) dendrimers is described. The applicability of these dendritic PARACEST MRI agents for pH mapping has been evaluated on a 7 T NMR spectrometer and on a 3 T clinical MRI scanner. As expected, based on the different numbers of exchangeable amide protons, the lowest detectable concentration of the first and third generation dendritic PARACEST agents is by a respective factor of about 4 and 16 lower than that of a mononuclear reference complex. The pH dependence of the CEST effect observed for these compounds depends on the generation of the poly(propylene imine) dendrimer. Upon going to higher generations of the Yb(III)DOTAM‐terminated dendrimer, a shift of the maximum CEST effect towards lower pH values was observed. This allows for a fine‐tuning of the responsive pH region by varying the dendritic framework. Copyright © 2007 John Wiley & Sons, Ltd.
Neoadjuvant therapy followed by prostatectomy for clinically localized prostate cancer
Authors: Sonpavde Guru , Chi Kim N. , Powles Thomas , Sweeney Christopher J. , Hahn Noah , Hutson Thomas E. , Galsky Matthew D. , Berry William R. , Kadmon Dov 
Published: October 2007

AbstractThe results of this assessment of the literature indicated that neoadjuvant therapy followed by prostatectomy may improve long‐term outcomes for patients with high‐risk localized disease. In addition, this approach provides a paradigm for evaluating the activity and mechanism of action of new agents as correlative studies are facilitated by the availability of tumor tissue before and after therapy. The authors determined that a multidisciplinary approach involving oncologists, urologists, and pathologists is critical to the success of this model. Recent and ongoing studies of neoadjuvant therapy followed by prostatectomy were reviewed. Cancer 2007. © 2007 American Cancer Society.
Molecular Dynamic Simulations of Ionic Liquids: A Reliable Description of Structure, Thermodynamics and Dynamics
Authors: Köddermann Thorsten , Paschek Dietmar , Ludwig Ralf 
Published: October 2007

AbstractThe parameterization of a new force‐field and its validation for the liquid description of five imidazolium‐based ionic liquids [Cnmim][NTf2] (n=1,2,4,6,8) are described. The proposed force‐field is derived to reproduce densities, self‐diffusion coefficients for cations and ions as well as NMR rotational correlation times for cations and water molecules in [C2mim][NTf2]. The temperature dependence and the cation chain‐length dependence of these properties is described well. Very good agreement between simulated and experimental values for the heats of vaporization, shear viscosities and NMR rotational correlation times is also achieved. All properties are crucial for understanding the nature and interaction of ionic liquids. The good performance of the new force‐field suggests that the Lennard–Jones interactions previously were strongly overestimated. The given force‐field now allows us to investigate other important properties of this class of ionic liquids such as the micro segregation of ionic liquids, ion pair formation, lifetimes of ion pairs and the solvent dependency of these properties.
Context‐specific calls signal infants' needs in a strepsirrhine primate, the gray mouse lemur (Microcebus murinus)
Authors: Scheumann Marina , Zimmermann Elke , Deichsel Guntram 
Published: October 2007

AbstractThe presence of context‐specific communication sounds, structurally different call types related to particular situations and potentially expressing distinct emotions of the caller, were not systematically studied in infants of strepsirrhine primates. We exposed suckling's of gray mouse lemurs (Microcebus murinus) in an infant separation paradigm to three distinct contexts (isolation, threat‐induced, grooming). An audio–videographic analysis of sound‐correlated infant behaviors and a simultaneous multiparametric sound analysis revealed context‐specific calls. Peak frequency predicted their acoustic classification best. Findings provided first evidence for a strepsirrhine primate that infant communication sounds may express distinct contexts and thereby infant's need reliably. © 2007 Wiley Periodicals, Inc. Dev Psychobiol 49: 708–718, 2007.
Preobesity in the infant OLETF rat: The role of suckling
Authors: Schroeder Mariana , Lavi‐Avnon Yael , Zagoory‐Sharon Orna , Weller Aron , Moran Timothy H. 
Published: October 2007

AbstractThe Otsuka Long Evans Tokushima Fatty (OLETF) rat model of obesity, which lacks CCK1 receptors, has been extensively investigated over the last decade. We have recently focused on the early developmental stages of this strain, finding that OLETF pups are heavier than controls from birth and hyperphagic already from postnatal (PN) Day 2. OLETF mothers present differential maternal behavior patterns and increased nursing time and frequency, which might contribute to the preobese characteristics of the pups. The present investigation examined the pups' ability to gain weight from the nursing episodes. First, we measured the pups' weight gain from one nursing bout from their own dam. Next we examined the pups' weight gain after a feeding competition test with control pups from foster dams of both strains. OLETF pups gained more weight than controls from their own dams on PN Week 1 due to a higher suckling rate (and/or efficacy) and on PN Week 3 due to increased nursing time. When competing with control pups, OLETF pups gained significantly more weight after the same nursing bout, regardless of the strain of the mother. Body mass index (BMI) was significantly higher in OLETF pups compared to controls. The maternal parameters assessed from the experiment were latencies to pup retrieval and to nursing, and nursing duration; differences were only observed in nursing time. OLETF dams increased their average nursing time over the PN weeks, while control dams decreased their nursing time toward weaning. The results suggest an important contribution of OLETF pups toward their own preobese development. © 2007 Wiley Periodicals, Inc. Dev Psychobiol 49: 685–691, 2007.
Advantages of mixed effects models over traditional ANOVA models in developmental studies: A worked example in a mouse model of fetal alcohol syndrome
Authors: Wainwright Patricia E. , Leatherdale Scott T. , Dubin Joel A. 
Published: October 2007

AbstractDevelopmental studies in animals often violate the assumption of statistical independence of observations due to the hierarchical nature of the data (i.e., pups cluster by litter, correlation of individual observations over time). Mixed effect modeling (MEM) provides a robust analytical approach for addressing problems associated with hierarchical data. This article compares the application of MEM to traditional ANOVA models within the context of a developmental study of prenatal ethanol exposure in mice. The results of the MEM analyses supported the ANOVA results in showing that a large proportion of the variability in both behavioral score and brain weight could be explained by ethanol. The MEM also identified that there were significant interactions between ethanol and litter size in relation to behavioral scores and brain weight. In addition, the longitudinal modeling approach using linear MEM allowed us to model for flexible weight gain over time, as well as to provide precise estimates of these effects, which would be difficult in repeated measures ANOVA. © 2007 Wiley Periodicals, Inc. Dev Psychobiol 49: 664–674, 2007.
Individual differences in salivary cortisol and alpha‐amylase in mothers and their infants: Relation to tobacco smoke exposure
Authors: Granger Douglas A. , Blair Clancy , Willoughby Michael , Kivlighan Katie T. , Hibel Leah C. , Fortunato Christine K. , Wiegand Lauren E. 
Published: October 2007

AbstractTobacco smoke exposure affects the activity of both the hypothalamic–pituitary–adrenal (HPA) axis and the sympathetic nervous system (SNS). Statistics reveal 41 million children in the U.S. are regularly exposed to tobacco smoke, but we know little about the effects of environmental tobacco smoke exposure on HPA and SNS activity in early childhood. This study assayed cotinine (a metabolite of nicotine), cortisol, and alpha‐amylase (sAA) in the saliva of mother–infant dyads from 197 low income and ethnically diverse families. The dyads were identified as tobacco smoke exposed (N = 82) or nonexposed (N = 115) based on maternal self‐reports of smoking and salivary cotinine levels greater or less than 10 ng/ml. As expected, higher rates of maternal smoking behavior were associated with higher levels of cotinine in mothers' and their infants' saliva. On average, smoking mothers' salivary cotinine levels were 281 times higher compared to their nonsmoking counterparts, and 23 times higher compared to their own infant's salivary cotinine levels. Infants of smoking mothers had salivary cotinine levels that were four times higher than infants with nonsmoking mothers. Mothers who smoked had higher salivary cortisol levels and lower sAA activity compared to nonsmoking mothers. There were no associations between maternal smoking behavior, infant's salivary cotinine levels, or tobacco exposure group, and cortisol or sAA measured in infant's saliva. The findings are discussed in relation to the influence of smoking tobacco on the validity of salivary biomarkers of stress. © 2007 Wiley Periodicals, Inc. Dev Psychobiol 49: 692–701, 2007.
Targeting reverse tetracycline‐dependent transactivator to murine mammary epithelial cells that express the progesterone receptor
Authors: Mukherjee Atish , Soyal Selma M. , Fernandez‐Valdivia Rodrigo , DeMayo Francesco J. , Lydon John P. 
Published: October 2007

AbstractThrough an established gene‐targeting strategy, reverse tetracycline‐dependent transactivator (rtTA) was targeted downstream of the murine progesterone receptor (PR) promoter. Mice were generated in which one (PR+/rtTA) or both (PRrtTA/rtTA) PR alleles harbor the rtTA insertion. The PR+/rtTA and PRrtTA/rtTA knockins exhibit phenotypes identical to the normal and the progesterone receptor knockout mouse, respectively. Crossed with the TZA reporter, which carries the TetO‐LacZ responder transgene, the PR+/rtTA/TZA and PRrtTA/rtTA/TZA bigenics exhibit doxycycline‐induced β‐galactosidase activity specifically in progesterone responsive target tissues such as the mammary gland, uterus, ovary, and pituitary gland. In the case of the PR+/rtTA/TZA mammary epithelium, dual immunofluorescence demonstrated that PR expression and doxycycline‐induced β‐galactosidase activity colocalized; β‐galactosidase was not detected in the absence of doxycycline. Although both the PR+/rtTA and PRrtTA/rtTA knockins represent innovative animal models with which to further query progesterone's mechanism of action in vivo, the PRrtTA/rtTA mouse in particular promises to provide unique insight into the paracrine mechanism of action, which underpins progesterone's involvement in mammary morphogenesis with obvious implications for extending our understanding of this steroid's role in breast cancer progression. genesis 45:639–646, 2007. © 2007 Wiley‐Liss, Inc.
Viral 2A peptides allow expression of multiple proteins from a single ORF in transgenic zebrafish embryos
Authors: Provost Elayne , Rhee Jerry , Leach Steven D. 
Published: October 2007

AbstractWe have adapted a novel multicistronic gene expression system involving viral peptides to the zebrafish. The viral 2A peptide allows production of multiple protein products from a single transgene. Based on highly inefficient peptide bond formation between glycine and proline residues within the 2A peptide, placement of 2A peptide sequence as a linker region between tandem cDNA's allows the stoichiometric translation of multiple unfused protein products. To test this system in zebrafish, we generated two different tandem reporter constructs employing eGFP and mCherry, separated by 2A peptide sequence. Using this system, we produced transgenic zebrafish in which fluorophores were produced as independent proteins from a single transcript. The successful application of this technology in zebrafish will be valuable for visually marking transgenic embryos and transgene‐expressing cells, or in any situation where reliable expression of multiple transgenes is desired. genesis 45:625–629, 2007. © 2007 Wiley‐Liss, Inc.