bluuebunny/crossref_metadata_2025_split huggingface dataset:
Micelles as Containers for Self‐Assembled Nanodevices: A Fluorescent Sensor for Lipophilicity
Authors: Chirico Giuseppe , Collini Maddalena , D'Alfonso Laura , Denat Franck , Diaz‐Fernandez Yuri A. , Pasotti Luca , Rousselin Yoann , Sok Nicolas , Pallavicini Piersandro 
Published: July 2008

AbstractPotentiometric titrations, fluorescence versus pH titrations, dynamic light scattering and fluorescence polarization anisotropy studies demonstrate that inside the nanodimensioned Triton X‐100 micelles, 1‐pyrenecarboxylic acid, PCOO−, forms an apical complex with the Zn2+ cation encircled by a lipophilic cyclen ligand and hugely increasing its fluorescence. The ability of the Zn2+‐cyclen‐PCOO− complex plus its micellar container to act as a fluorescent sensor to evaluate the lipophilicity of molecular species is demonstrated on the fatty acid series CH3(CH2)xCOOH (x=0–16). At pH 7.4 a decrease in fluorescence is observed on the addition of fatty acids that is directly related to their chain length, that is, to their tendency to enter the micellar containers, where they dislocate PCOO− from the Zn2+ centre. The independent determination of fatty acid pKa values in the presence of Triton X‐100 micelles confirms that our fluorescent micellar device is capable of sensing their lipophilicity.
Experimental determination of sample stream focusing with fluorescent dye
Authors: Taylor Jay , Stubley G. D. , Ren Carolyn L. 
Published: July 2008

AbstractThis study aims to develop an experimental method for determining the focused‐sample stream width in microfluidic chips. The focused‐sample stream width in the junction of a cross‐linked microchannel is determined by the distance between the two streamlines dividing the focusing sheath streams and the sample stream, which should be insensitive to the sample properties. However, the commonly used FWHM intensity method is dependent on the dye properties and cannot be used to estimate the sample focusing effects very accurately. The proposed method is based upon the fact that the cross‐stream concentration profile of the sample stream in a region downstream of the junction matches the Gaussian distribution. Therefore, the width of the focused sample stream can be estimated from the channel widths and the variance and maximum concentration of the experimentally measured concentration profile. To validate this method, fluorescein dye has been used to obtain the concentration profile. It has been shown that the proposed method is independent of the fluorescent dye properties. Comparison between the proposed method, FWHM method, and some reported analytical methods also validates the proposed method.
Protein separation using preparative‐scale dynamic field gradient focusing
Authors: Tracy Noah I. , Ivory Cornelius F. 
Published: July 2008

AbstractDynamic field gradient focusing uses an electric field gradient to separate and concentrate proteins in native buffers. A prototype preparative‐scale dynamic field gradient focusing apparatus reproducibly separated hemoglobin and bovine serum albumin with a mean resolution of 2.64 ± 0.503. Run‐to‐run variations in the hemoglobin's focal point and peak width appeared to be related to fluctuations in the shape of the electric field, rather than the 5% accuracy of the pump that provided the counter‐flow in the separation annulus. The variation in the electric field gradient was probably due to the formation and expansion of an ion‐depleted region at the top of the separation annulus.
Evaluation of confidence and reproducibility in quantitative proteomics performed by a capillary isoelectric focusing‐based proteomic platform coupled with a spectral counting approach
Authors: Balgley Brian M. , Wang Weijie , Song Tao , Fang Xueping , Yang Li , Lee Cheng S. 
Published: July 2008

AbstractMultidimensional separations of the peptides resulting from enzymatic digestions of complex protein mixtures prior to MS/MS, namely shotgun proteomics, is increasingly utilized for large‐scale identification and quantitation of proteins. Inherent to the performance of proteomic measurements is the resolving power of each of the separations both separately and in combination. By simply raising the number of CIEF fractions, the resulting enhancement in the overall peak capacity of combined CIEF/nano‐RPLC separations greatly reduces the complexity of eluted peptides prior to MS detection and sequencing and increases the proteome coverage. The capabilities of the CIEF‐based proteome platform coupled with the spectral counting approach to confidently and reproducibly quantify proteins and changes in protein expression levels among samples are evaluated. Analytical reproducibility of relative protein abundance is determined to exhibit a Pearson R2 value greater than 0.99 and a CV of 14.1%. The platform is demonstrated to be capable of measuring changes in protein expression as low as 1.5‐fold, with confidence following multiple testing adjustment.
Analyzing dynamic performance of stressed power systems in vicinity of instability by modal series method
Authors: Naghshbandy Ali H. , Shanechi Hasan Modir , Kazemi Ahad , Pourfar Iman 
Published: July 2008

AbstractHighly stressed power systems exhibit complex dynamic behaviors such as inter‐area oscillations when subjected to large disturbances. In such conditions, nonlinear effects have dominant role in determining dynamic response of the systems. In this paper by using modal series method, dynamic behaviors of the stressed power systems in severe conditions and near instability have been studied. Also two measures, mode dominance measure (MDM) and most perturbed machine factor (MPF) have been introduced. They determine the most dominant modes and identify the most perturbed generators when the system is subjected to a given fault. Contribution factors have been used to show the links between identified modes and machines from the analysis. Time domain simulation has been helped for validation of the results. By using similarity transformation, state variables have been represented in modal space and utilized to check the results. The studies are carried out on the IEEE 50‐generator test system which demonstrates a wide range of dynamic characteristics at different loading levels and fault scenarios. Copyright © 2008 John Wiley & Sons, Ltd.
Diet‐induced insulin resistance impairs hippocampal synaptic plasticity and cognition in middle‐aged rats
Authors: Stranahan Alexis M. , Norman Eric D. , Lee Kim , Cutler Roy G. , Telljohann Richard S. , Egan Josephine M. , Mattson Mark P. 
Published: July 2008

AbstractOverall dietary energy intake, particularly the consumption of simple sugars such as fructose, has been increasing steadily in Western societies, but the effects of such diets on the brain are poorly understood. Here, we used functional and structural assays to characterize the effects of excessive caloric intake on the hippocampus, a brain region important for learning and memory. Rats fed with a high‐fat, high‐glucose diet supplemented with high‐fructose corn syrup showed alterations in energy and lipid metabolism similar to clinical diabetes, with elevated fasting glucose and increased cholesterol and triglycerides. Rats maintained on this diet for 8 months exhibited impaired spatial learning ability, reduced hippocampal dendritic spine density, and reduced long‐term potentiation at Schaffer collateral—CA1 synapses. These changes occurred concurrently with reductions in levels of brain‐derived neurotrophic factor in the hippocampus. We conclude that a high‐calorie diet reduces hippocampal synaptic plasticity and impairs cognitive function, possibly through BDNF‐mediated effects on dendritic spines. Published 2008 Wiley‐Liss, Inc.
6‐(Diazomethyl)‐1,3‐bis(methoxymethyl)uracil, Synthesis and Transformation into Annulated Pyrimidinediones
Authors: Zhang Fuyi , Kulesza Anna , Rani Shikha , Bernet Bruno , Vasella Andrea 
Published: July 2008

Abstract6‐(Diazomethyl)‐1,3‐bis(methoxymethyl)uracil (5) was prepared from the known aldehyde 3 by hydrazone formation and oxidation. Thermolysis of 5 and deprotection gave the pyrazolo[4,3‐d]pyrimidine‐5,7‐diones 7a and 7b. Rh2(OAc)4 catalyzed the transformation of 5 into to a 2 : 1 (Z)/(E) mixture of 1,2‐diuracilylethenes 9 (67%). Heating (Z)‐9 in 12n HCl at 95° led to electrocyclisation, oxidation, and deprotection to afford 73% of the pyrimido[5,4‐f]quinazolinetetraone 12. The Rh2(OAc)4‐catalyzed reaction of 5 with 3,4‐dihydro‐2H‐pyran and 2,3‐dihydrofuran gave endo/exo‐mixtures of the 2‐oxabicyclo[4.1.0]heptane 13 (78%) and the 2‐oxabicyclo[3.1.0]hexane 15 (86%), Their treatment with AlCl3 or Me2AlCl promoted a vinylcyclopropane–cyclopentene rearrangement, leading to the pyrano‐ and furanocyclopenta[1,2‐d]pyrimidinediones 14 (88%) and 16 (51%), respectively. Similarly, the addition product of 5 to 2‐methoxypropene was transformed into the 5‐methylcyclopenta‐pyrimidinedione 18 (55%). The Rh2(OAc)4‐catalyzed reaction of 5 with thiophene gave the exo‐configured 2‐thiabicyclo[3.1.0]hexane 19 (69%). The analoguous reaction with furan led to 8‐oxabicyclo[3.2.1]oct‐2‐ene 20 (73%), and the reaction with (E)‐2‐styrylfuran yielded a diastereoisomeric mixture of hepta‐1,4,6‐trien‐3‐ones 21 (75%) that was transformed into the (1E,4E,6E)‐configured hepta‐1,4,6‐trien‐3‐one 21 (60%) at ambient temperature.
Squalene‐Derived Triterpene Polyethers from the Red Alga Laurencia omaezakiana
Authors: Matsuo Yoshihide , Suzuki Minoru , Masuda Michio , Iwai Toshiyuki , Morimoto Yoshiki 
Published: July 2008

AbstractIn our continuing search on halogenated metabolites from species of the red algal genus Laurencia, a novel squalene‐derived triterpene polyether, named omaezakianol (2), was isolated from Laurencia omaezakiana Masuda along with 15,16‐anhydrothyrsiferol (3). Their structures were determined by spectral and chemical methods.
Five New Aromatic Glycosides from Carthamus tinctorius
Authors: Zhou Yu‐Zhi , Chen Huan , Qiao Li , Lu Xuan , Hua Hui‐Ming , Pei Yue‐Hu 
Published: July 2008

AbstractFive new aromatic glycosides, 1–5, named as carthamosides B4–B8, together with three known compounds, 4′‐(hydroxyphenacyl)‐β‐D‐glucopyranoside (6), benzyl‐O‐α‐L‐rhamnopyranosyl‐(1→6)‐β‐D‐glucopyranoside (7), and 4‐(methoxybenzyl)‐O‐β‐D‐glucopyranoside (8), have been isolated from the air‐dried flower of Carthamus tinctorius. Their structures were identified on the basis of chemical and spectroscopic methods.
Triumfettamide and Triumfettoside Ic, Two Ceramides and Other Secondary Metabolites from the Stems of WildTriumfetta cordifoliaA. Rich. (Tiliaceae)
Authors: Pergaud Sandjo Louis , Hannewald Paul , Yemloul Mehdi , Kirsch Gilbert , Tchaleu Ngadjui Bonaventure 
Published: July 2008

AbstractTwo new ceramides, triumfettamide (1) and triumfettoside Ic (2), characterized as (2R,6Z)‐2‐hydroxy‐N‐[(2S,3S,4R)‐1,3,4‐trihydroxyhexacosan‐2‐yl]heptadec‐6‐enamide and (2R)‐N‐{(1S,2R,3E,6Z, 9Z,12Z,15Z)‐1‐[(β‐D‐glucopyranosyloxy)methyl]‐2‐hydroxyheneicosa‐3,6,9,12,15‐pentaen‐1‐yl}‐2‐hydroxytetradecanamide, respectively, were isolated from the stems ofTriumfetta cordifoliaA. Rich.besides eight known secondary metabolites identified as heptadecanoic acid,β‐sitosterol glucopyranoside, friedelin, lupeol, betulin, maslinic acid, 2‐hydroxyoleanolic acid and the mixture of stigmasterol andβ‐sitosterol. Their structures were determined on the basis of spectroscopic methods as well as HR‐MALDI‐FT‐ICR‐MS analysis, chemical transformation, and by comparison of their physical and spectral data with those reported in the literature and with authentic specimens for some known compounds. Five pentacyclic triterpenoids, friedelin, lupeol, betulin, maslinic acid, and 2‐hydroxyoleanolic acid, have been isolated fromTriumfettagenus for the first time.
New Antifungal Terpenoid Glycosides from Alibertia edulis (Rubiaceae)
Authors: Cândida da Silva Viviane , Soares Mendes Giannini Maria José , Carbone Virginia , Piacente Sonia , Pizza Cosimo , da Silva Bolzani Vanderlan , Nasser Lopes Márcia 
Published: July 2008

AbstractPhytochemical investigation from the stems of Alibertia edulis led to the isolation and identification of a new iridoid 6β‐hydroxy‐7‐epigardoside methyl ester (1) and a new saponin 3β‐O‐[α‐L‐rhamnopyranosyl‐(1→2)‐O‐β‐D‐glucopyranosyl‐(1→2)‐O‐β‐D‐glucopyranosyl]‐28‐O‐β‐D‐glucopyranoside pomolate (2), along with three known compounds, shanzhiside methyl ester (3), ixoside (4), and 3,4,5‐trimethoxyphenyl 1‐O‐β‐D‐apiofuranosyl‐(1→6)‐O‐β‐D‐glucopyranoside (5). The structures of 1 and 2 were established on the basis of their spectroscopic data. Iridoid 1 and saponin 2 exhibited moderate inhibitory activities against Candida albicans and C. krusei in a dilution assay.
A Convenient and Efficient Method for the Preparation of Unique Fluorophores of Lariat Naphtho‐Aza‐Crown Ethers
Authors: Sharghi Hashem , Ebrahimpourmoghaddam Sakineh 
Published: July 2008

AbstractNew naphtho‐aza‐crown ethers containing different phenolic side‐arms attached through the ortho‐position of the phenol have been prepared under solvent‐free conditions. The starting macrocyclic naphtho‐aza‐crown ether 2 was obtained by treatment of naphthalene dicarboxylic acid diester 1 with diethylenetriamine in EtOH at room temperature for two days without stirring in 77% yield (Scheme 1). Phenolic ligands (3–14) were synthesized by the Mannich reaction of the secondary macrocyclic amine 2 with the substituted phenols using nontoxic and inexpensive CaCl2. This procedure was applied successfully for the synthesis of Mannich bases from simple secondary amines. The CaCl2 powder can be reused up to three times after simple washing with dry acetone.
Experimental and Theoretical Studies on DNA‐Binding and Spectral Properties of ‘Light Switch’ Complexes [Ru(L)2(ppn)]2+ (L=2,2′‐Bipyridine and 1,10‐Phenanthroline; ppn=Pteridino[6,7‐f] [1,10]phenanthroline‐11,13‐diamine)
Authors: Liu Xue‐Wen , Chen Jin‐Can , Hu Xia , Li Hong , Zheng Kang‐Cheng , Ji Liang‐Nian 
Published: July 2008

AbstractThe ligand pteridino[6,7‐f] [1,10]phenanthroline‐11,13‐diamine (ppn) and its RuII complexes [Ru(bpy)2(ppn)]2+ (1; bpy=2,2′‐bipyridine) and [Ru(phen)2(ppn)]2+ (2; phen=1,10‐phenanthroline) were synthesized and characterized by elemental analysis, electrospray MS, 1H‐NMR, and cyclic voltammetry. The DNA‐binding behaviors of 1 and 2 were studied by spectroscopic and viscosity measurements. The results indicate that both complexes strongly bind to calf‐thymus DNA in an intercalative mode, with DNA‐binding constants Kb of (1.7±0.4)⋅106 M−1 and (2.6±0.2)⋅106 M−1, respectively. The complexes 1 and 2 exhibit excellent DNA‐‘light switch’ performances, i.e., they do not (or extremely weakly) show luminescence in aqueous solution at room temperature but are strongly luminescent in the presence of DNA. In particular, the experimental results suggest that the ancillary ligands bpy and phen not only have a significant effect on the DNA‐binding affinities of 1 and 2 but also have a certain effect on their spectral properties. [Ru(phen)2(ppn)]2+(2) might be developed into a very prospective DNA‐‘light switch’ complex. To explain the DNA‐binding and spectral properties of 1 and 2, theoretical calculations were also carried out applying the DFT/TDDFT method.
Nanotubes Made from Deeply Undercooled Cryolite/Alumina Melts
Authors: Korenko Michal , Kucharík Marián , Oboňa Jozef Vincenc , Janičkovič Dušan , Córdoba Rosa , De Teresa José María , Kubíková Blanka 
Published: July 2008

AbstractThe rapid‐solidification processing (by a cooling rate of 105–106 K/s) was used for the preparation of deeply undercooled cryolite/alumina (Na3AlF6/Al2O3) melts. We found a mass of nanotubes on the surface of these undercooled melts. The nanotubes were preferentially located on the defect places of the surface with the following approximate dimensions: base≈100×100 nm, length≈1000 nm. The solidified samples with the nanotubes on the surface were analyzed by scanning electron microscopy (SEM), energy‐dispersive X‐ray spectroscopy (EDX), X‐ray diffraction (XRD), and infrared spectroscopy (IR).
Application of the Alpine 3D model for glacier mass balance and glacier runoff studies at Goldbergkees, Austria
Authors: Michlmayr Gernot , Lehning Michael , Koboltschnig Gernot , Holzmann Hubert , Zappa Massimiliano , Mott Rebecca , Schöner Wolfgang 
Published: July 2008

AbstractThe model for mountain surface processes, Alpine 3D, was applied to the Goldbergkees basin (2·7 km2, 52% glacierized) in the central Austrian Alps to model hourly discharge and glacier mass balance. Alpine 3D is a physically based model which focuses on snow‐ice‐soil energy and mass fluxes (without lateral, gravity driven flows) in rugged terrain. From the records of the Sonnblick observatory, located in the study area, a high‐quality set of meteorological, glaciological and hydrological data could be provided to force and evaluate the model. A 1‐year period was simulated starting from September 2004. The model results were evaluated using observations of the glacier mass balance and discharge at the catchment outlet. The spatial variation of modelled annual net mass balance of Goldbergkees shows good agreement to observed data. Significant deviations occur mainly at locations, which are presumably influenced by avalanche events or drifting snow. The quality of runoff simulation was estimated using the Nash–Sutcliffe model efficiency and the explained variance number. Both criteria demonstrate that the modelled catchment discharge is of satisfactory quality, despite the fact that the local mass balance is not well represented at all grid points. Copyright © 2008 John Wiley & Sons, Ltd.
What do we know about serotonin?
Authors: Jonnakuty Catherine , Gragnoli Claudia 
Published: July 2008

AbstractThe present review focuses on what is known of basic serotonin physiology in the human body. Here, we describe serotonin biochemistry and metabolism and summarize the results of studies that have contributed significantly to our understanding of serotonin physiology. We report the well‐established role of serotonin in cardiovascular, gastrointestinal, and circulatory physiology. Emphasis is placed on the role of serotonin in peripheral physiological systems rather than in the central nervous system. A brief overview is provided on the emerging role of serotonin in novel areas such as bone pathways and glucose uptake. We also report a select few animal studies and animal models that have provided worthwhile contributions to the understanding of serotonin in human physiology. In addition, we summarize the results of large‐scale genetic studies on serotonin and serotonin transporter genes, performed in relation to behavioral and mood disorders. J. Cell. Physiol. 217: 301–306, 2008. © 2008 Wiley‐Liss, Inc.
Transcriptional profiling defines the effects of nickel in human epidermal keratinocytes
Authors: Gazel Alix , Rosdy Martin , Tornier Carine , De Fraissinette Anne De Brugerolle , Blumenberg Miroslav 
Published: July 2008

AbstractNickel is a ubiquitous and virtually unavoidable environmental pollutant and occupational hazard, but its molecular and cellular effects are not well understood. Human epidermal keratinocytes are the sentinel and the primary target for nickel. We treated with nickel salts skin equivalents containing differentiating epidermal keratinocytes grown on air–liquid interface in standard cell culture conditions. We identified the transcriptional profiles affected by nickel in reconstructed human epidermis (RHE) using DNA microarrays. The Ni‐regulated genes were determined at two time points, immediate‐early, 30 min after treatment, and late, at 6 h. Using in silico data analysis, we determined that 134 genes are regulated by nickel; of these, 97 are induced and 37 suppressed. Functional categories of regulated genes suggest that Ni inhibits apoptosis, promotes cell cycle and induces synthesis of extracellular matrix proteins and extracellular proteases. Importantly, Ni also regulates a set of secreted signaling proteins, inducing VEGF, amphiregulin, PGF, GDF15, and BST2, while suppressing IL‐18, galectin‐3, and LITAF. These secreted proteins may be important in Ni‐caused allergic reactions. Ni induced inhibitors of the NFκB signaling pathway, and suppressed its activators. Correspondingly, NFκB binding sites were found to be overrepresented in the Ni‐suppressed genes, whereas cFOS/AP1 binding sites were common in the Ni‐induced genes. Significant parallels were found between the Ni‐regulated genes and the genes regulated by TGFβ, EGF, glucocorticoids, or Oncostatin‐M. The comprehensive identification of Ni‐regulated genes in human epidermal equivalents significantly advances our understanding of the molecular effects of nickel in skin. J. Cell. Physiol. 217: 686–692, 2008. © 2008 Wiley‐Liss, Inc.
Induction of HIF‐1α expression by intermittent hypoxia: Involvement of NADPH oxidase, Ca2+ signaling, prolyl hydroxylases, and mTOR
Authors: Yuan Guoxiang , Nanduri Jayasri , Khan Shakil , Semenza Gregg L. , Prabhakar Nanduri R. 
Published: July 2008

AbstractSleep‐disordered breathing with recurrent apnea (periodic cessation of breathing) results in chronic intermittent hypoxia (IH), which leads to cardiovascular and respiratory pathology. Molecular mechanisms underlying IH‐evoked cardio‐respiratory co‐morbidities have not been delineated. Mice with heterozygous deficiency of hypoxia‐inducible factor 1α (HIF‐1α) do not develop cardio‐respiratory responses to chronic IH. HIF‐1α protein expression and HIF‐1 transcriptional activity are induced by IH in PC12 cells. In the present study, we investigated the signaling pathways associated with IH‐evoked HIF‐1α accumulation. PC12 cells were exposed to aerobic conditions (20% O2) or 60 cycles of IH (30 sec at 1.5% O2 followed by 5 min at 20% O2). Our results show that IH‐induced HIF‐1α accumulation is due to increased generation of ROS by NADPH oxidase. We further demonstrate that ROS‐dependent Ca2+ signaling pathways involving phospholipase Cγ (PLCγ) and protein kinase C activation are required for IH‐evoked HIF‐1α accumulation. IH leads to activation of mTOR and S6 kinase (S6K) and rapamycin partially inhibited IH‐induced HIF‐1α accumulation. IH also decreased hydroxylation of HIF‐1α protein and anti‐oxidants as well as inhibitors of Ca+2 signaling prevented this response. Thus, both increased mTOR‐dependent HIF‐1α synthesis and decreased hydroxylase‐dependent HIF‐1α degradation contribute to IH‐evoked HIF‐1α accumulation. Following IH, HIF‐1α, and phosphorylated mTOR levels remained elevated during 90 min of re‐oxygenation despite re‐activation of prolyl hydroxylase. Rapamycin or cycloheximide, blocked increased HIF‐1α levels during re‐oxygenation indicating that mTOR‐dependent protein synthesis is required for the persistent elevation of HIF‐1α levels during re‐oxygenation. J. Cell. Physiol. 217: 674–685, 2008. © 2008 Wiley‐Liss, Inc.