bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation of the Effect of Four Organic Acids in Radix Isatidis onE. coliGrowth by Microcalorimetry
Authors: KONG Wei‐Jun , ZHAO Yan‐Ling , SHAN Li‐Mei , XIAO Xiao‐He , GUO Wei‐Ying
Published: January 2008

The inhibitory effects of four organic acids (OAs) inRadix Isatidis, a traditional Chinese medicinal herb, onEscherichia coli(E. coli) growth were investigated by microcalorimetry. The power‐time curves ofE. coligrowth with and without OAs were acquired, meanwhile the extent and duration of inhibitory effects on the metabolism were evaluated by growth rate constants (k1,k2), half inhibitory ratio (IC50), maximum heat output (Pmax) and peak time (tp). The values ofk1andk2ofE. coligrowth in the presence of the four OAs decreased with the increasing concentrations of OAs. Moreover,Pmaxwas reduced and the value oftpincreased with increasing concentrations of the four drugs. The sequence of anti‐microbial activity of the four OAs was: syringic acid>2‐amino‐benzoic acid>salicylic acid>benzoic acid. IC50of the four OAs was respectively 56 µg/mL for syringic acid, 75 µg/mL for 2‐amino‐benzoic acid, 86 µg/mL for salicylic acid and 224 µg/mL for benzoic acid. The existence of the functional groups on phenyl ring improves the anti‐microbial activity compared to benzoic acid. The functional groups methoxyl at C(3) and C(5) improve anti‐microbial activity more strongly than the other functional groups, and the functional group amino at C(2) improve anti‐microbial activity more strongly than hydroxyl at C(2) on phenyl ring.
Synthesis and Evaluation of Optical 2‐Benzyl‐5‐bromo‐4‐oxopentanoic Acids as Transition‐state Analog Inhibitors against Carboxypeptidase A
Authors: JIN Jing‐Yi , WANG Shou‐Feng , XUAN Wei , SHENG Ji‐Wen , WANG Si‐Hong , TIAN Guan‐Rong
Published: January 2008

Both enantiomers of 2‐benzyl‐5‐bromo‐4‐oxopentanoic acid were prepared utilizing the diazo ketones as the key intermediates. The compounds were assayed for inhibitory activity against carboxypeptidase A (CPA, EC 3.4.17.1). The (R)‐form is 260‐fold more potent than the corresponding (S)‐form. The finding that (R)‐form, which belongs to the L‐series, is mostly responsible for the inhibitory activity accords with the substrate specificity of CPA. For comparison, both the optical forms of 2‐benzyl‐4‐oxopentanoic acid were also synthesized and evaluated as the inhibitors against CPA. These results reveal that the introduction of a bromo group at the α‐position of ketones can significantly enhance the electrophilicity of the carbonyl group. Further molecular docking study suggested that the gem‐diol form of the α‐bromo ketone, which mimics the transition state in the CPA catalytic process, could chelate the zinc ion in the active site of CPA and thus result in the strong inhibition.
Amination Reactions of Aryl Halides with Nitrogen‐Containing Reagents Catalyzed by CuI in Ionic Liquid
Authors: YAN Jin‐Can , ZHOU Li , WANG Lei
Published: January 2008

CuI‐catalyzed coupling reactions of aryl iodides and electron‐deficient aryl bromides with nitrogen‐containing reagents, such as imidazole, benzimidazole, aliphatic primary and secondary amines, aniline, primary and secondary amides, in ionic liquid were developed. The reaction conditions involved the use of [Bmim][BF4] as the solvent, potassium phosphate as the base, and CuI as the catalyst. The CuI and [Bmim][BF4] could be recovered and recycled for five consecutive trials without significant loss of their activity.
Iodine Catalyzed One‐pot Synthesis of 3,4‐Dihydroquinazolin‐4‐ones from Anthranilic Acids, Ortho Esters and Amines under Solvent‐free Conditions
Authors: WANG Hong‐She , ZENG Jun‐E
Published: January 2008

A simple and efficient procedure has been developed for the one‐pot synthesis of 3,4‐dihydroquinazolin‐4‐ones from anthranilic acids, ortho esters and amines using a catalytic amount of iodine under solvent‐free conditions to afford the corresponding products in excellent yields. The direct use of commercially available catalyst, mild and solvent‐free reaction conditions, short reaction time, easy workup and excellent yields are the advantages of the present protocol.
Guanidine‐Functionalized Resin‐Supported Pd(0) Catalyst: Activity, Reusability, and Redeposition of Active Pd Species in Heck Vinylation
Authors: YANG Yuan‐Fa , LU Mao‐Ling , XU Bin , ZENG Zhao‐Xia
Published: January 2008

The guanidine‐functionalized resin‐supported Pd(0) catalyst [GDR·Pd(0)] is highly active in Heck reaction of aryl bromides with acrylic acid or styrene without the need to exclude air. The catalyst can be recycled at least 9 times without significant loss of activity in N‐methyl‐2‐pyrrolidone at 140 °C. The Heck reaction proceeds homogeneously with dissolved palladium species and the dissolved active palladium species can redeposit onto the surface of catalyst in the reaction. The XRD peak shifting of Pd phases in the catalyst provides the evidence for the re‐deposition of the active palladium species.
Vibrational Spectrum of o‐Dimethoxybenzene in the S1 and D0 States
Authors: HUANG Jian‐Han , ZENG Wen‐Bi , HUANG Ke‐Long
Published: January 2008

The optimized molecular geometries of o‐dimethoxybenzene (ODMB) in the S0 state were predicted by ab initio and density functional theory calculations. Its vibrational spectra in the S1 and D0 states were studied by one color resonant two photon ionization (1C‐R2PI) and mass analyzed threshold ionization (MATI) experiments. The results indicated that trans rotamer was most stable. Only one rotamer of ODMB was detected by the 1C‐R2PI spectra, and its band origin was (35750±2) cm−1, its ionization energy was (61617±5) cm−1. Most of the observed vibrations in the D0 state resulted from the in‐plane ring and substituent sensitive modes.
Synthesis and Characterization of Nanostructured Manganese Dioxide Used as Positive Electrode Material for Electrochemical Capacitor with Lithium Hydroxide Electrolyte
Authors: YUAN An‐Bao , ZHOU Min , WANG Xiu‐Ling , SUN Zi‐Hong , WANG Yu‐Qin
Published: January 2008

A nanostructured manganese dioxide electrode material was prepared using a solid‐reaction route starting with MnCl2·4H2O and NH4HCO3, and its electrochemical performance as a positive electrode for MnO2/activated carbon hybrid supercapacitor with 1 mol·L−1 LiOH electrolyte was reported. The material was proved to be a mixture of nanostructured γ‐MnO2 and α‐MnO2 containing some bound water in the structure, which was characterized by X‐ray diffraction analysis, infrared spectrum analysis, and transmission electron microscope observation. Electrochemical properties of the MnO2 electrode and the MnO2/AC capacitor were investigated by cyclic voltammetry, ac impedance and galvanostatic charge/discharge methods. Experimental results showed that the MnO2 electrode exhibited faradaic pseudocapacitance behavior and higher specific capacitance in 1 mol·L−1 LiOH electrolyte. The MnO2/AC hybrid capacitor with 1 mol·L−1 LiOH electrolyte presented excellent rate charge/discharge ability and cyclic stability.
Electronic Structures and Spectroscopy of Luminescent para‐Phenylenevinylene Oligomers
Authors: DING Liang , DING Yu‐Qi , TENG Qi‐Wen , WANG Ke
Published: January 2008

The computational models for a series of PPV (para‐phenylenevinylene) oligomers were formed based on the biphenyl and stilbene structures. These oligomers were optimized using DFT at B3LYP/6‐31G (d) level. On the basis of the optimized geometries, the electronic spectra and 13C NMR spectra were calculated by the INDO/CIS and B3LYP/6‐31G(d) methods, respectively. It indicates that the main absorptions in the electronic spectra are red‐shifted when the oligomer length is increased. The main absorptions in the electronic spectra and the 13C chemical shifts are altered obviously when the substituents on the matrix are changed.
Actin stress fiber pre‐extension in human aortic endothelial cells
Authors: Lu Lan , Feng Yunfeng , Hucker William J. , Oswald Sara J. , Longmore Gregory D. , Yin Frank C‐P
Published: January 2008

Actin stress fibers (SFs) enable cells to sense and respond to mechanical stimuli and affect adhesion, motility and apoptosis. We and others have demonstrated that cultured human aortic endothelial cells (HAECs) are internally stressed so that SFs are pre‐extended beyond their unloaded lengths. The present study explores factors affecting SF pre‐extension. In HAECs cultured overnight the baseline pre‐extension was 1.10 and independent of the amount of cell shortening. Decreasing contractility with 30 mM BDM or 10 μM blebbistatin decreased pre‐extension to 1.05 whereas increasing contractility with 2 nM calyculin A increased pre‐extension to 1.26. Knockdown of α‐actinin‐1 with an interfering RNA increased pre‐extension to 1.28. None of these affected the wavelength of the buckled SFs. Pre‐extension was the same in unperturbed cells as in those in which the actin cytoskeleton was disrupted by both chemical and mechanical means and then allowed to reassemble. Finally, disrupting MTs or IFs did not affect pre‐extension but increased the wavelength. Taken together, these results suggest that pre‐extension of SFs is determined primarily by intrinsic factors, i.e. the level of actin‐myosin interaction. This intrinsic control of pre‐extension is sufficiently robust that pre‐extension is the same even after the actin cytoskeleton has been disrupted and reorganized. Unlike pre‐extension, the morphology of the compressed SFs is partially determined by MTs and IFs which appear to support the SFs along their lengths. Cell Motil. Cytoskeleton 2008. © 2008 Wiley‐Liss, Inc.
Role of neurophysiology in the clinical practice of primary pediatric headaches
Authors: Raieli V. , Puma D. , Brighina F.
Published: January 2008

The role of electrophysiological studies in pediatric headaches is controversial. In childhood headaches, neurophysiological examinations are of interest for potential clinical use because they are noninvasive and are scarcely influenced by environmental factors or drug use. Electrophysiological studies in childhood headache principally explored the role of electroencephalographic (EEG) evaluations in migraine, while less evidence has been reported about other neurophysiological techniques, such as evoked potentials, event‐related potentials, and, less often, transcranial magnetic stimulation. In this brief review, we point out our attention to the aid of neurophysiological methods in the clinical diagnosis of pediatric headaches. Although many examinations are actually of little value in the clinical setting, they may have a potential role in some clinical subgroups or in monitoring and evaluating the effects of pharmacological treatment. Drug Dev Res 68:389–396, 2007. © 2008 Wiley‐Liss, Inc.
Meningeal mast cells, inflammation and migraine pain
Authors: Levy Dan
Published: January 2008

Migraine is a debilitating, throbbing headache that afflicts about 15% of the Western population. While the underlying cause of migraine is still a matter of speculation, the intracranial throbbing pain of migraine is largely attributed to an episode of local sterile meningeal inflammation that promote activation of trigeminal mechanosensitive nociceptive afferents that supply the meninges. The key players responsible for triggering such nociceptive neuronal events remain poorly defined, however. Mast cells, resident inflammatory cells that populate the meninges, particularly the dura mater, were implicated in the pathophysiology of migraine more than 50 years ago. Additional clinical and preclinical data that further support their role in migraine have recently emerged. This review highlights these findings, examines the evidence of a neuroimmune interaction between meningeal nociceptors and mast cells, in particular their involvement in promoting the activation and sensitization of the trigeminovascular systems, and will finally discuss the notion that in some migraine attacks, mast cells serve as an intermediate between various migraine triggers and the persistent activation of meningeal nociceptors. Drug Dev Res 68:412–418, 2007. © 2008 Wiley‐Liss, Inc.
Supplementary treatment of migraines
Authors: Upton Adrian R.M. , Clarke Beverley M.
Published: January 2008

Medications are the current standard treatment of migraine headache, but a number of physical therapies show promising results, including acupuncture, occipital nerve stimulation, and transcranial magnetic stimulation (TMS). Occipital nerve stimulation may control headache in 70–75% of cases, but the procedure requires subcutaneous electrodes. TMS is noninvasive and is well tolerated, with success rates of 69–87%. Development of portable small TMS devices should shorten the time to treatment and improve efficacy. Migraine can be controlled at the stage of aura. Drug Dev Res 68:428–431, 2007. © 2008 Wiley‐Liss, Inc.
Overview of treatment of acute migraine
Authors: Elkind Arthur H. , Ishkanian Gary , Mereddy Suresh R.
Published: January 2008

Acute migraine is a major public health problem with a significant economic burden secondary to short‐term disability and absenteeism. Treatment of acute migraine is always challenging for primary care physicians and family practitioners, as there are no set universal guidelines for the treatment of acute migraine. In acute migraine treatment, nonsteroidal anti‐inflammatory drugs (NSAIDs), migraine‐specific medications, and adjunctive medications are used, depending on the severity of acute migraine attacks. Treatment of acute migraine has changed drastically since the introduction of the triptans. However, even after the introduction of triptans, nearly one‐half of migraine sufferers are still being treated with over‐the‐counter medications. In this literature review, we mention drugs that are being used in the treatment of acute migraine and their level of evidence recommended by the U.S. Headache Consortium. This article gives special emphasis to pharmacokinetics and clinical characteristics of all available triptans. Drug Dev Res 68:441–448, 2007. © 2008 Wiley‐Liss, Inc.
Ligand stabilization of CXCR4/δ‐opioid receptor heterodimers reveals a mechanism for immune response regulation
Authors: Pello Oscar M. , Martínez‐Muñoz Laura , Parrillas Verónica , Serrano Antonio , Rodríguez‐Frade José Miguel , Toro María José , Lucas Pilar , Monterrubio María , Martínez‐A Carlos , Mellado Mario
Published: January 2008

The CXCR4 chemokine receptor and the delta opioid receptor (DOR) are pertussis toxin‐sensitive G protein‐coupled receptors (GPCR). Both are widely distributed in brain tissues and immune cells, and have key roles in inflammation processes and in pain sensation on proximal nerve endings. We show that in immune cells expressing CXCR4 and DOR, simultaneous addition of their ligands CXCL12 and [D‐Pen2, D‐Pen5]enkephalin does not trigger receptor function. This treatment does not affect ligand binding or receptor expression, nor does it promote heterologous desensitization. Our data indicate that CXCR4 and DOR form heterodimeric complexes that are dynamically regulated by the ligands. This is compatible with a model in which GPCR oligomerization leads to suppression of signaling, promoting a dominant negative effect. Knockdown of CXCR4 and DOR signaling by heterodimerization might have repercussions on physiological and pathological processes such as inflammation, pain sensation and HIV‐1 infection.

See accompanying article:http://dx.doi.org/10.1002/eji200738101
Antibody deficiency diseases
Authors: Pan‐Hammarström Qiang , Hammarström Lennart
Published: January 2008

Primary immunodeficiency diseases are rare disorders characterized by quantitative or qualitative defects in cells or components in the immune system, resulting in a high degree of susceptibility to various types of infections. During differentiation, stem cells undergo a series of discrete steps, governed by a large number of different genes. Mutations/deletions in these genes will result in a block in differentiation of the affected cell lineage(s), leading to immunodeficiency. To date, more than 150 different types of disorders have been described. In this review, we will focus on novel findings in antibody deficiency syndromes.
Complexation of 2,6‐Bis(3‐pyrazolyl)pyridine–Bis(thiocyanato)iron(II) with a Bridging 4,4′‐Bipyridine: A New Example of a Dinuclear Spin Crossover Complex
Authors: Fedaoui Dalila , Bouhadja Yacine , Kaiba Abdellah , Guionneau Philippe , Létard Jean‐François , Rosa Patrick
Published: January 2008

Investigation of the coordination behavior of 2,6‐bis(3‐pyrazolyl)pyridine–bis(thiocyanato)iron(II) towards bridging ligands led to the discovery of a novel dinuclear complex showing spin‐crossover. Chemical and structural characterization and a first report of physical properties are presented.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Theoretical Design of Silicon–Phosphorus Triple Bonds: A Density Functional Study
Authors: Chen Chi‐Hui , Su Ming‐Der
Published: January 2008

A density functional study on the effects of bulky aryl substituents on silicon–phosphorus triple bonds was carried out by using the B3LYP/3‐21G* method. These investigations suggest that both the kinetic and thermodynamic stabilities of substituted (L–Si≡P–L)+1 molecules are strongly dependent on the substituents (L). That is to say, the triply bonded (L–Si≡P–L)+1 molecule can be synthetically accessible by a proper choice of bulky aryl substituents. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Synthesis of Nanocrystalline Iron Oxide Particles in the Iron(III) Acetate/Alcohol/Acetic Acid System
Authors: Gotić Marijan , Musić Svetozar
Published: January 2008

Nanosized iron oxide particles were synthesised without the addition of water by autoclaving iron(III) acetate/alcohol and iron(III) acetate/acetic acid/alcohol solutions at 180 °C for different time periods. Magnetite was formed in iron(III) acetate/ethanol, whereas hematite was formed in the iron(III) acetate/acetic acid/ethanol system. The average crystallite sizes of 11.1 and 22.6 nm and the stoichiometry of Fe2.89O4 were found for the nanosized magnetite particles. The primary magnetite particles aggregated into regular spheres 5 to 10 μm in size, which can be explained by the specific character of the small, reactive and polar molecules of ethanol. In the iron(III) acetate/octanol system, a mixture of magnetite and hematite was obtained. The average crystallite size of magnetite was up to 22 nm and that of hematite was up to 46.7 nm. In the iron(III) acetate/acetic acid/ethanol system, nanosized hematite particles were exclusively formed. 13C NMR spectroscopy revealed the presence of ethyl acetate ester in the supernatants. The formation of ester in the iron(III) acetate/ethanol system was explained by the catalytic oxidation of ethanol in the presence of acetate groups bonded to iron. Thus, in the oxidative dehydrogenation of ethanol into ethyl acetate, coordinated Fe3+ served as an electron acceptor that was reduced to Fe2+, and exclusively magnetite was formed. With the addition of acetic acid to the iron(III) acetate/ethanol system, the free acetic acid directly participated in an esterification reaction with ethanol. Water molecules generated in situ in this esterification reaction hydrolysed iron(III) acetate, and thus hematite was formed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Effects of Precipitation, SolGel Synthesis Conditions, and Drying Methods on the Properties of Nano‐TiO2 for Photocatalysis Applications
Authors: Junin Chabaiporn , Thanachayanont Chanchana , Euvananont Chanipat , Inpor Kroekchai , Limthongkul Pimpa
Published: January 2008

A comparative study of TiO2 powders prepared by precipitation and sol–gel methods was conducted. Titanium tetrachloride and titanium tetraisopropoxide were used as the starting materials for the precipitation and sol–gel processes, respectively. The effects of the two different drying methods, freeze drying and normal drying at 100 °C, of the precipitates on the properties of the prepared TiO2 powders were also investigated. The effects of the synthesis methods on phase, surface area, crystallite size, and photodegradation of methylene blue were studied by XRD, SEM, TEM, BET, and UV/Vis techniques. It was found that the major phase of the synthesized TiO2 was anatase, but small amounts of the brookite phase (<10 %) were found in some samples. The synthesized anatase TiO2 with no pretreatment was found to be stable up to 600 °C for the samples prepared by the precipitation method, whereas a small amount of rutile was detected for the sample prepared by the sol–gel method when heated to 600 °C. Effects of the different processing methods on phase, particle size, surface area, and photocatalytic activity were not highly pronounced. However, the calcination temperature was found to have a strong influences on the properties. As the calcination temperature increased, the size of the crystallite and the percent degradation of methylene blue were found to increase, whereas the surface area was found to decrease. These results indicate the degree of crystallinity has a greater effect on the photocatalytic activity than the surface area for nano‐TiO2 synthesized by these methods.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Dynamic Behaviour of the [(Triphos)Rh(η1:η2‐P4RR′)]n+ Complexes [Triphos = MeC(CH2PPh2)3; R = H, Alkyl, Aryl; R′ = Lone Pair, H, Me; n = 0, 1]: NMR and Computational Studies
Authors: Barbaro Pierluigi , Caporali Maria , Ienco Andrea , Mealli Carlo , Peruzzini Maurizio , Vizza Francesco
Published: January 2008

Solution multinuclear and multidimensional NMR analyses of the [(triphos)Rh(η1:η2‐P4RR′)]n+ complex cations [triphos = MeC(CH2PPh2)3; R = H, Me, Ph; R′ = lone pair, H, Me; n = 0, 1] confirm the same primary structure determined by X‐rays in the solid state. In addition, 2D 1H NOESY and 31P{1H} exchange NMR spectroscopy show that these complexes are nonrigid on the NMR time‐scale over the 253–318 K temperature range. A dynamic process that involves the terminal phosphane groups of the triphos ligand is displayed by each compound. The NMR spectroscopic data indicate a slow scrambling motion in which the P4R unit tumbles with respect to the (triphos)Rh moiety. DFT calculations outline a possible turnstile mechanism involving the threefold and twofold rotors into which the complex is subdivided. The process goes through a transition state in which the axial and equatorial dispositions of the PRR′ and P=P donating groups of the P4RR′ ligand are inverted with respect to the ground state. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Synthesis, Electrochemical and Optical Properties of RuII–Diphenylphenanthroline–Ethynylpyrenephenanthroline Systems
Authors: Goze Christine , Sabatini Cristiana , Barbieri Andrea , Barigelletti Francesco , Ziessel Raymond
Published: January 2008

The synthesis, electrochemical and optical spectroscopic properties of a RuII–diphenylphenanthroline complex decorated with ethynylpyrene (EP) appendages, 1, and those of its parent bromo‐substituted complex, 2, are reported; complex 1 is [Ru(dpp)2(phen–EP2)](PF6)2 and 2 is [Ru(dpp)2(phen–Br2)](PF6)2, where dpp is 4,7‐diphenyl‐1,10‐phenanthroline, phen–EP is 5,6‐(1‐ethynylpyrene)‐1,10‐phenanthroline and phen–Br2 is 5,6‐dibromo‐1,10‐phenanthroline. In CH3CN solvent, both bromo‐ and EP‐substituted complexes are redox active and metal‐centred and ligand‐centred processes are assigned with reference to the analogous steps for [Ru(phen)3]2+ and to steps for the EP appendages. The complexes exhibit strong absorption bands in the near‐UV and visible regions due to ligand‐centred (LC) and metal‐to‐ligand charge‐transfer (MLCT) transition, respectively. For 1, the lowest‐lying absorption band is slightly redshifted due to better delocalisation at the phen–EP ligand. At room temperature and in O2‐free solvent, complex 1 appeared to be practically nonluminescent, whereas 2 exhibited intense 3MLCT emission; quantum yields of fem = 9 × 10–4 and 6.1 × 10–2 were found for 1 and 2, respectively and λexc = 462 nm in both cases. The lowest‐lying excited states of 1 were assigned as 3LC states, which were localised on the EP moiety. These states are nonluminescent, which thus explains the weak room‐temperature luminescence for this complex. At 77 K, 2 is emissive, as expected for 3MLCT levels; however, a moderately intense 3MLCT emission was also observed for 1 at this temperature. For the latter case, this outcome is tentatively explained in terms of local trapping of 3MLCT states at the 4,7‐diphenylphenanthroline ligands free of EP appendages.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Microwave‐Assisted Hydrothermal Synthesis of Structurally and Morphologically Controlled Sodium Niobates by Using Niobic Acid as a Precursor
Authors: Paula Amauri J. , Zaghete Maria A. , Longo Elson , Varela José A.
Published: January 2008

There are many advantages to using a microwave as a source of heat in hydrothermal reactions. Because it is a quick and homogeneous way to crystallize ceramic powders, it was used in this work for the production of antiferroelectric sodium niobate (NaNbO3) in a cubic‐like form and its intermediary phase, disodium diniobate hydrate (Na2Nb2O6.H2O), with a fiber morphology. The syntheses were carried out by treating niobic acid (Nb2O5·nH2O) with NaOH. By changing the reaction time and the concentration of the reactants, particles with different structures and different morphologies could be obtained. The structural evolution of the products of this reaction was elucidated on the basis of the arrangement of the NbO6 octahedral units. Conclusive results were obtained with morphological and structural characterizations through XRD, TEM, MEV, and NMR and Raman spectroscopy. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Synthesis of Polyprenylated Benzoylphloroglucinols by Regioselective Prenylation of Phloroglucinol in an Aqueous Medium
Authors: Raikar Sanjay B. , Nuhant Philippe , Delpech Bernard , Marazano Christian
Published: January 2008

Regioselective tri‐C‐prenylation of phloroglucinol, leading to a compound with gem‐disubstitution, has been achieved with prenyl bromide in the presence of potassium hydroxide in an aqueous medium. Geranyl‐ and isolavandulylphloroglucinol, obtained by ortho‐lithiation, were diprenylated under the same conditions. C‐Benzoylation of the trialkylated derivatives using benzoyl cyanide in the presence of triethylamine afforded two natural products, grandone and kolanone, and an isomer of weddellianone A. Attemped electrophilic cyclization reactions, aimed at a biomimetic synthesis of polycyclic polyprenylated acylphloroglucinols (PPAPs), are also reported. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Intermolecular and Intramolecular Pauson–Khand Reactions of Functionalized Allenes
Authors: González‐Gómez Álvaro , Añorbe Loreto , Poblador Amalia , Domínguez Gema , Pérez‐Castells Javier
Published: January 2008

Pauson–Khand reactions of functionalized allenes with different alkynes give cyclopentenones with generally high regio‐ and stereoselectivities. The allenes react through their external double bonds, giving cyclopentenones with exocyclic double bond at their β positions and predominantly with E stereochemistry. Some intramolecular reactions with allenynes connected through aromatic rings are described. These give the corresponding heterocycles with moderate to good yields.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Synthesis of Indene and Naphthalene Derivatives by a Palladium‐Catalyzed Domino Carbopalladation/Cyclization/Coupling Process
Authors: Guo Li‐Na , Duan Xin‐Hua , Hu Jie , Bi Hai‐Peng , Liu Xue‐Yuan , Liang Yong‐Min
Published: January 2008

Highly substituted indene and naphthalene derivatives have been readily prepared in good‐to‐high yields by a palladium‐catalyzed domino reaction. This domino reaction involves a Heck carbopalladation/cyclization/coupling process. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Nucleophilic Substitution at C, Si and P: How Solvation Affects the Shape of Reaction Profiles (Eur. J. Org. Chem. 4/2008)
Authors: van Bochove Marc A. , Bickelhaupt F. Matthias
Published: January 2008

The cover picture shows that solvation smoothes reaction profiles not only for SN2 reactions at carbon but also for SN2 reactions at silicon, tricoordinate phosphorus and tetracoordinate phosphorus. Thus, the characteristic double‐well, single‐well and triple‐well structures on the gas‐phase potential energy surfaces (PES) disappear, which results, in all cases, in a unimodal reaction profile in solution. Details are discussed in the article by M. A. van Bochove and F. M. Bickelhaupt on p. 649 ff. We thank Dr. Marcello Luppi for the design of the cover picture.
Crosslinked hyaluronic acid dermal fillers: A comparison of rheological properties
Authors: Falcone Samuel J. , Berg Richard A.
Published: January 2008

Temporary dermal fillers composed of crosslinked hyaluronic acid (XLHA) are space filling gels that are readily available in the United States and Europe. Several families of dermal fillers based on XLHA are now available and here we compare the physical and rheological properties of these fillers to the clinical effectiveness. The XLHA fillers are prepared with different crosslinkers, using HA isolated from different sources, have different particle sizes, and differ substantially in rheological properties. For these fillers, the magnitude of the complex viscosity, |η*|, varies by a factor of 20, the magnitude of the complex rigidity modulus, |G*|, and the magnitude of the complex compliance, |J*| vary by a factor of 10, the percent elasticity varies from 58% to 89.9%, and the tan δ varies from 0.11 to 0.70. The available clinical data cannot be correlated with either the oscillatory dynamic or steady flow rotational rheological properties of the various fillers. However, the clinical data appear to correlate strongly with the total concentration of XLHA in the products and to a lesser extent with percent elasticity. Hence, our data suggest the following correlation: dermal filler persistence = [polymer] × [% elasticity] and the clinical persistence of a dermal filler composed of XLHA is dominated by the mass and elasticity of the material implanted. This work predicts that the development of future XLHA dermal filler formulations should focus on increasing the polymer concentration and elasticity to improve the clinical persistence. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Histological and biomechanical properties of regenerated articular cartilage using chondrogenic bone marrow stromal cells with a PLGA scaffold in vivo
Authors: Han Seung Hwan , Kim Yun Hee , Park Min Sung , Kim In Ae , Shin Jung Woog , Yang Woo Ick , Jee Kyoung Soo , Park Ki Dong , Ryu Gyu Ha , Lee Jin Woo
Published: January 2008

The properties of regenerated cartilage using bone marrow‐derived mesenchymal stem cells (MSCs) and poly lactic‐co‐glycolic acid (PLGA) scaffold composites pretreated with TGF‐β3 were investigated and compared to the non‐TGF‐β3 treated MSCs/PLGA composites in a rabbit model. We prepared MSCs/PLGA scaffold composites and pretreated it with TGF‐β3 for 3 weeks prior to transplantation. Then, composites were transplanted to the osteochondral defect in the rabbit knee. After 12 weeks of transplantation, 10 of the 12 rabbits in which TGF‐β3 pretreated MSCs/PLGA scaffold composites were transplanted showed cartilaginous regeneration. In gross morphology, regenerated cartilage showed smooth, flush, and transparent features. In indentation test, this had about 80% of Young's modulus of normal articular cartilage. Histological examination demonstrated hyaline like cartilage structures with glycosaminoglycan and type II collagen expression. Histological scores were not statistically different to the normal articular cartilage. These results showed improvement of cartilage regeneration compared to the non‐TGF‐β3 pretreated MSCs/PLGA scaffold composite transplanted group. Thus, we have successfully regenerated improved hyaline‐like cartilage and determined the feasibility of treating damaged articular cartilage using MSCs/PLGA scaffold composite pretreated with TGF‐β3. Also, we suggest this treatment modality as another concept of cartilage tissue engineering. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Evaluation of the biocompatibility of calcium phosphate cement/PLGA microparticle composites
Authors: Link Dennis P. , van den Dolder Juliette , van den Beucken Jeroen J. J. P. , Cuijpers Vincent M. , Wolke Joop G. C. , Mikos Antonios G. , Jansen John A.
Published: January 2008

In this study, the biocompatibility of a calcium phosphate (CaP) cement incorporating poly (D,L‐lactic‐co‐glycolic acid) (PLGA) microparticles was evaluated in a subcutaneous implantation model in rats. Short‐term biocompatibility was assessed using pure CaP discs and CaP discs incorporating PLGA microparticles (20% w/w) with and without preincubation in water. Long‐term biocompatibility was assessed using CaP discs incorporating varying amounts (5, 10, or 20% w/w) and diameter sizes (small, 0–50 μm; medium, 51–100 μm, or large, 101–200 μm) of PLGA microparticles. The short‐term biocompatibility results showed a mild tissue response for all implant formulations, irrespective of disc preincubation, during the early implantation periods up to 12 days. Quantitative histological evaluation revealed that the different implant formulations induced the formation of similar fibrous tissue capsules and interfaces. The results concerning long‐term biocompatibility showed that all implants were surrounded by a thin connective tissue capsule (<10 layers of fibroblasts). Additionally, no significant differences in capsule and interface scores were observed between the different implant formulations. The implants containing 20% PLGA with medium‐ and large‐sized microparticles showed fibrous tissue ingrowth throughout the implants, indicating PLGA degradation and interconnectivity of the pores. The results demonstrate that CaP/PLGA composites evoke a minimal inflammatory response. The implants containing 20% PLGA with medium‐ and large‐sized microparticles showed fibrous tissue ingrowth after 12‐ and 24‐weeks indicating PLGA degradation and interconnectivity of the pores. Therefore, CaP/PLGA composites can be regarded as biocompatible biomaterials with potential for bone tissue engineering and advantageous possibilities of the microparticles regarding material porosity. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Linear and ultrafast optical spectroscopy in the regime of the quantum Hall effect
Authors: Broocks K.‐B. , Su B. , Schröter P. , Heyn Ch. , Heitmann D. , Wegscheider W. , Apalkov V. M. , Chakraborty T. , Perakis I. E. , Schüller C.
Published: January 2008

We review our optical experiments on two‐dimensional electron systems (2DES) of different mobilities, realized in modulation‐doped GaAs–AlGaAs single quantum wells, in quantizing magnetic fields. The carrier densities of the 2DESs could be tuned in a quite broad range between about 1 × 1010 cm–2 and 2 × 1011 cm–2 via gate electrodes. In photoluminescence (PL) and absorption experiments on 2DES with moderate mobility, at very low electron densities, we have observed the formation of negatively charged excitons. In these experiments, we could identify a dark triplet exciton, which is observable at temperatures below 1 K and for electron filling factors v < 1/3 i.e., in the fractional quantum Hall regime, only. In experiments where we have increased the density of the 2DES so that a uniform 2DES starts to form, we have found a strong energetic anomaly of the charged excitons in the vicinity of filling factor 1/3. The anomaly could be explained by a model, assuming that at very low temperatures localized charged excitons and a uniform Laughlin liquid coexist. Furthermore, we report on ultrafast optical experiments at the v = 1 quantum Hall state of a high‐mobility 2DES in a GaAs–AlGaAs single quantum well. By spectrally‐resolved four‐wave‐mixing experiments, we have investigated the coherent dynamics of photo‐excited electron–hole pairs and found extraordinarily long decoherence times for electrons, excited into the upper spin level, around v = 1 We attribute the observed faster decay of the dephasing time for v < 1 as compared to v > 1 presumably to the coherent coupling of the spin levels via spin waves. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Separately contacted edge states at high imbalance in the integer and fractional quantum Hall effect regime
Authors: Deviatov E. V. , Lorke A.
Published: January 2008

This review presents experimental results on the inter‐edge‐state transport in the quantum Hall effect, mostly obtained in the regime of high imbalance. The application of a special geometry makes it possible to perform I –V spectroscopy between individual edge channels in both the integer and the fractional regime. This makes it possible to study in detail a number of physical effects such as the creation of topological defects in the integer quantum Hall effect and neutral collective modes excitation in fractional regime. While many of the experimental findings are well explained within established theories of the quantum Hall effects, a number of observations give new insight into the local structure at the sample edge, which can serve as a starting point for further theoretical studies. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Laughlin's function on a cylinder: plasma analogy and representation as a quantum polymer
Authors: Jansen Sabine , Lieb Elliott H. , Seiler Ruedi
Published: January 2008

We investigate Laughlin's fractional quantum Hall effect wave function in the cylinder geometry of Laughlin's integer quantum Hall effect argument, at filling factor 1/3. We show that the plasma analogy leads to a periodic density, and that the wave function admits a representation as a “quantum polymer”, reminiscent of the quantum dimer model by Rokhsar and Kivelson. We explain how the representation can be exploited to compute the normalization and one‐particle density in the limit of infinitely many particles. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Associations between peer victimization, self‐reported depression and social phobia among adolescents: The role of comorbidity
Authors: Ranta Klaus , Kaltiala‐Heino Riittakerttu , Pelkonen Mirjami , Marttunen Mauri
Published: January 2008

Associations of peer victimization with adolescent depression and social phobia (SP), while controlling for comorbidity between them, have not been sufficiently explored in earlier research. A total of 3156 Finnish adolescents aged 15–16 years participated in a survey study. Self‐reported peer victimization, as well as self‐reported depression (Beck Depression Inventory), SP (Social Phobia Inventory), and selected background variables were assessed. Frequency of overt and covert peer victimization was examined among four groups: (1) adolescents with depression non‐comorbid with SP (DEP), (2) those with SP non‐comorbid with depression (SP), (3) those with both SP and depression (SP+DEP), and (4) controls, with neither. A logistic regression analysis controlling for confounding familial (family moving, parental unemployment), and psychopathology (delinquency, aggressiveness, general anxiety) covariates was conducted to confirm the associations between peer victimization and the four groups. Among boys the comorbid SP+DEP group reported the highest rates of both overt and covert victimization, these being significantly higher than among both DEP and SP groups. Among girls covert victimization was again most frequent in the SP+DEP group, but overt victimization was not more frequent in the comorbid group than it was in the DEP and SP groups. In the logistic regression analysis depression without SP did not maintain an independent association with either type of victimization. Instead, SP without depression with ORs from 2.8 to 4.3, and SP comorbid with depression, with ORs between 3.2 and 11.4 had independent associations with peer victimization. In conclusion, overt and covert peer victimization seem to be associated with SP, rather than depression, among adolescents.
May duration of untreated illness influence the long-term course of major depressive disorder?
Authors: Altamura A. Carlo , Dell'Osso Bernardo , Vismara Serena , Mundo Emanuela
Published: January 2008

The aim of this naturalistic study was to investigate the possible influence of the duration of untreated illness (DUI) on the long-term course of Major Depressive Disorder (MDD). One hundred and thirteen patients with recurrent MDD, according to DSM-IV-TR criteria, followed up for 5 years, were selected, interviewed and their clinical charts were reviewed. The DUI was defined as the interval between the onset of the first depressive episode and the first adequate antidepressant treatment. The sample was divided into two groups according to the DUI: one group with a DUI ≤ 12 months (n = 75), and the other with a DUI > 12 months (n = 38). The main demographic and clinical course variables were compared between the two groups using Student's t-tests or chi-square tests. Patients with a longer DUI showed an earlier age at onset (t = 2.82, p = 0.006) and a longer duration of illness (t = 3.20, p = 0.002) compared to patients with a shorter DUI. In addition, the total number of depressive episodes occurring before the first antidepressant treatment was higher in the group with a longer DUI (t = −2.223, p < 0.03). Even though limited by the retrospective nature of the study, these preliminary findings would suggest that a longer DUI may negatively influence the course of MDD. Larger prospective studies are warranted to further investigate the role of the DUI within MDD.
BARRIERS TO THE USE OF MODERN CONTRACEPTIVES AND IMPLICATIONS FOR WOMAN-CONTROLLED PREVENTION OF SEXUALLY TRANSMITTED INFECTIONS IN MADAGASCAR
Authors: RANDRIANASOLO BODO , SWEZEY TERESA , VAN DAMME KATHLEEN , KHAN MARIA R. , RAVELOMANANA NORO , LOVANIAINA RABENJA NY , RAHARINIVO MBOLATIANA , BELL APRIL J. , JAMIESON DENISE ,   THE MAD STI PREVENTION GROUP, BEHETS FRIEDA
Published: January 2008

Globally, unplanned pregnancies and sexually transmitted infections (STIs) persist as significant threats to women’s reproductive health. Barriers to the use of modern contraceptives by women might inhibit uptake of novel woman-controlled methods for preventing STIs/HIV. Use of modern contraceptives and perceptions and attitudes towards contraceptive use were investigated among women in Antananarivo, Madagascar, using qualitative research. The hypothetical acceptability of the diaphragm – a woman-controlled barrier contraceptive device that also holds promise of protecting against STIs/HIV – was assessed. Women consecutively seeking care for vaginal discharge at a public health clinic were recruited for participation in a semi-structured interview (SSI) or focus group discussion (FGD). Audiotaped SSIs and FGDs were transcribed, translated and coded for predetermined and emerging themes. Of 46 participating women, 70% reported occasional use of male condoms, mostly for preventing pregnancy during their fertile days. Although women could name effective contraceptive methods, only 14% reported using hormonal contraception. Three barriers to use of modern contraceptives emerged: gaps in knowledge about the range of available contraceptive methods; misinformation and negative perceptions about some methods; and concern about social opposition to contraceptive use, mainly from male partners. These results demonstrate the need for programmes in both family planning and STI prevention to improve women’s knowledge of modern contraceptives and methods to prevent STI and to dispel misinformation and negative perceptions of methods. In addition, involvement of men will probably be a critical component of increased uptake of woman-controlled pregnancy and STI/HIV prevention methods and improved health.
Successful Control of Aggregation and Folding Rates during Refolding of Denatured Lysozyme by Adding N‐Methylimidazolium Cations with Various N′‐Substituents
Authors: Yamaguchi Satoshi , Yamamoto Etsushi , Tsukiji Shinya , Nagamune Teruyuki
Published: January 2008

The present study aimed to obtain more effective refolding agents and to understand the influence of their chemical structures on their function as refolding agents. To achieve these aims, we investigated the effects of a large variety of N′‐substituted N‐methylimidazolium chlorides on the oxidative refolding of lysozyme in a high throughput manner. Among the molecules examined, N‐methylimidazolium cations with a short N′‐alkyl chain, such as an N′‐ethyl or N′‐butyl chain, significantly enhanced the refolding yield compared to conventional refolding additives such as arginine hydrochloride and Triton X‐100. Detailed kinetic analyses revealed that the effective cations selectively decreased the aggregation rate constant ( kA) without any large decreases in the folding rate constant ( kN). However, when the hydrophobicity of the N′‐substituent of the cations was increased, the desirable properties of the short N′‐alkyl chain‐type cations for protein refolding were diminished. Furthermore, increases in the N′‐alkyl chain length to an N′‐octyl or N′‐dodecyl chain drastically decreased the kA values, thereby increasing the ratio of kN to kA, despite the very small kN values and resulting in enhanced refolding yields. Thus, by tuning the chemical structure of the N′‐substituents of N‐methylimidazolium chloride, five effective refolding agents ( N′‐ethyl‐, N′‐propyl‐, N′‐butyl‐, N′‐pentyl‐ and N′‐isobutyl‐ N‐methylimidazolium chlorides) were successfully obtained, and the kinetic parameters of folding and aggregation during the refolding process could be controlled using three different modes.
Arousal of Flow Experience in a Learning Setting and Its Effects on Exam Performance and Affect
Authors: Schüler Julia
Published: January 2008

Abstract. Flow experience is associated with learning motivation, performance and positive affect. Therefore it is important to analyze its antecedents. An important antecedent for experiencing flow is the balance between the person's skill and how challenging the situation is ( Csikszentmihalyi, 1990 ). According to Atkinson's (1957) risk-taking model, only individuals with high hope-of-success prefer situations in which a balance of challenge and skill is given while individuals with high fear-of-failure try to avoid such situations. Integration of these two lines of research leads to the suggestion that the achievement motive might moderate the relationship between the challenge-skill balance and flow experience. This notion could be confirmed in two studies with undergraduate students (N = 57/N = 395). Additionally, flow experience was found to be a significant predictor of affect (Study 1 and 2) and exam performance (Study 2). I discuss these findings and their practical implications for academic learning settings.
Influence of “defects” on sorted bedform dynamics
Authors: Huntley David A. , Coco Giovanni , Bryan Karin R. , Murray A. Brad
Published: January 2008

Bedforms with plan‐view patterns consisting of long crests interrupted by defects occur ubiquitously in subaqueous and subaerial environments where they strongly influence flows and sediment transport. We explore how such patterns adjust to changes in the external forcing. We utilize a numerical model of a wide‐spread, large‐scale seabed pattern, ‘sorted bedforms,’ examining their response to changes in wave forcing. Numerical experiments show that the pattern adjustment progresses through two stages characterized by defect propagation and defect creation, respectively, and that the rates of the initial stage, and therefore overall pattern adjustment, are determined by the initial defect density. All characteristics of the sorted bedforms are similarly influenced by the presence of defects. Although the processes of growth are likely to be different for other types of bedforms, it is reasonable to expect they will be similarly influenced by defects in pre‐existing patterns.