bluuebunny/crossref_metadata_2025_split huggingface dataset:
“Click Peptide“: pH‐Triggered in Situ Production and Aggregation of Monomer Aβ1–42
Authors: Taniguchi Atsuhiko , Sohma Youhei , Hirayama Yuta , Mukai Hidehito , Kimura Tooru , Hayashi Yoshio , Matsuzaki Katsumi , Kiso Yoshiaki 
Published: February 2009

AbstractInto neutral: We demonstrate the unique features of a pH click peptide based on an O‐acyl isopeptide method. Under acidic conditions, the click peptide remains in a monomeric form. Upon increase of the pH to 7.4, the click peptide is quickly able to convert into Aβ1–42 through an O‐to‐N intramolecular acyl migration. Further study using this pH click peptide would elucidate the pathological role of Aβ1–42 in Alzheimer's disease.magnified imageThe intense and uncontrollable self‐assembling nature of amyloid β peptide (Aβ) 1–42 is known to cause difficulties in preparing monomeric Aβ1–42; this results in irreproducible or discrepant study outcomes. Herein, we report novel features of a pH click peptide of Aβ1–42 that was designed to overcome these problems. The click peptide is a water‐soluble precursor peptide of Aβ1–42 with anO‐acyl isopeptide structure between the Gly25–Ser26 sequence. The click peptide adopts and retains a monomeric, random coil state under acidic conditions. Upon change to neutral pH (pH click), the click peptide converts to Aβ1–42 promptly (t1/2≈10 s) and quantitatively through an O‐to‐N intramolecular acyl migration. As a result of this quick and irreversible conversion, monomer Aβ1–42 with a random coil structure is produced in situ. Moreover, the oligomerization, amyloid fibril formation and conformational changes of the produced Aβ1–42 can be observed over time. This click peptide strategy should provide a reliable experimental system to investigate the pathological role of Aβ1–42 in Alzheimer's disease.
Lewis Acid Catalyzed Cascade Reactions of 1,6‐Diynes and 1,6‐Enynes with Vinylidenecyclopropanes
Authors: Yao Liang‐Feng , Shi Min 
Published: February 2009

AbstractCascade reactions: Lewis acid catalyzed cascade reactions of 1,6‐diynes and 1,6‐enynes with arylvinylidenecyclopropanes produce polycyclic compounds and isopropylidene‐3,3‐diarylcyclobut‐1‐enylmethyl derivatives (see scheme) in good to high yields along with a PtCl2‐catalyzed cyclization and a Cu(OAc)2⋅H2O‐catalyzed Eglinton coupling reaction.magnified imageLewis acid catalyzed reactions of N‐(4‐hydroxy‐4,4‐diarylbut‐2‐ynyl)‐4‐methyl‐N‐prop‐2‐ynylbenzenesulfonamides or 1,1‐diphenyl‐4‐prop‐2‐ynyloxybut‐2‐yn‐1‐ol (1,6‐diynes) 1 and N‐allyl‐N‐(4‐hydroxy‐4,4‐diarylbut‐2‐ynyl)‐4‐methylbenzenesulfonamides (1,6‐enynes) 2 with vinylidenecyclopropanes 3 selectively produce polycyclic compounds 4, 5 and 10 as well as isopropylidene‐3,3‐diarylcyclobut‐1‐enylmethyl derivatives 6 or 7 in good to high yields depending on the substituents on the benzene ring of 3 under mild conditions. An interesting PtCl2‐catalyzed cyclization of 6 and a Cu(OAc)2⋅H2O catalyzed Eglinton coupling reaction of 5 and 10 to produce the corresponding 5‐isopropylidene‐6‐methyl‐1‐(toluene‐4‐sulfonyl)‐7‐vinyl‐1,2,3,4,5,8‐hexahydroazocine derivatives 8 and the coupling products 9 and 11 in good yields have been disclosed, respectively. Plausible mechanisms of these processes have been proposed that belong to a cascade rearrangement followed by the Friedel–Crafts reaction, an intramolecular proton transferring and a cyclization reaction.
Stereoselectivity of the Hydrogen‐Atom Transfer in Benzophenone–Tyrosine Dyads: An Intramolecular Kinetic Solvent Effect
Authors: Hörner Gerald , Hug Gordon L. , Lewandowska Anna , Kazmierczak Franciszek , Marciniak Bronislaw 
Published: February 2009

AbstractTo be or not to be solvated is the decisive parameter that controls the photoinduced hydrogen‐atom transfer in diastereomeric ketone/phenol dyads. A kinetic solvent effect that refers to hydrogen bonding between the phenol and the solvent is suggested to be the main source of the stereoselective discrimination in the hydrogen transfer (see figure).magnified image
Induction of a Melanoma‐Specific Antibody Response by a Monovalent, but not a Divalent, Synthetic GM2 Neoglycopeptide
Authors: Bay S. , Fort S. , Birikaki L. , Ganneau C. , Samain E. , Coïc Y‐M. , Bonhomme F. , Dériaud E. , Leclerc C. , Lo‐Man R. 
Published: February 2009

AbstractHuman tumor cell‐specific antibodies were induced in mice after immunization with a synthetic glycopeptide, which is based on the GM2 ganglioside carbohydrate moiety produced on a gram scale in bacteria. Such neoglycopeptides represent a promising cancer vaccine strategy for active immunotherapy targeting carbohydrates.magnified imageThe GM2 ganglioside represents an important target for specific anticancer immunotherapy. We designed and synthesized a neoglycopeptide immunogen displaying one or two copies of the GM2 tetrasaccharidic moiety. These glycopeptides were prepared using the Huisgen cycloaddition, which enables the efficient ligation of the alkyne‐functionalized biosynthesized GM2 with an azido CD4+ T cell epitope peptide. It is worth noting that the GM2 can be produced on a gram scale in bacteria, which can be advantageous for a scale‐up of the process. We show here for the first time that a fully synthetic glycopeptide, which is based on a ganglioside carbohydrate moiety, can induce human tumor cell‐specific antibodies after immunization in mice. Interestingly, the monovalent, but not the divalent, form of GM2 peptide construct induced antimelanoma antibodies. Unlike traditional vaccines, this vaccine is a pure chemically‐defined entity, a key quality for consistent studies and safe clinical evaluation. Therefore, such carbohydrate–peptide conjugate represents a promising cancer vaccine strategy for active immunotherapy targeting gangliosides.
Equal numbers of neuronal and nonneuronal cells make the human brain an isometrically scaled‐up primate brain
Authors: Azevedo Frederico A.C. , Carvalho Ludmila R.B. , Grinberg Lea T. , Farfel José Marcelo , Ferretti Renata E.L. , Leite Renata E.P. , Filho Wilson Jacob , Lent Roberto , Herculano‐Houzel Suzana 
Published: February 2009

AbstractThe human brain is often considered to be the most cognitively capable among mammalian brains and to be much larger than expected for a mammal of our body size. Although the number of neurons is generally assumed to be a determinant of computational power, and despite the widespread quotes that the human brain contains 100 billion neurons and ten times more glial cells, the absolute number of neurons and glial cells in the human brain remains unknown. Here we determine these numbers by using the isotropic fractionator and compare them with the expected values for a human‐sized primate. We find that the adult male human brain contains on average 86.1 ± 8.1 billion NeuN‐positive cells (“neurons”) and 84.6 ± 9.8 billion NeuN‐negative (“nonneuronal”) cells. With only 19% of all neurons located in the cerebral cortex, greater cortical size (representing 82% of total brain mass) in humans compared with other primates does not reflect an increased relative number of cortical neurons. The ratios between glial cells and neurons in the human brain structures are similar to those found in other primates, and their numbers of cells match those expected for a primate of human proportions. These findings challenge the common view that humans stand out from other primates in their brain composition and indicate that, with regard to numbers of neuronal and nonneuronal cells, the human brain is an isometrically scaled‐up primate brain. J. Comp. Neurol. 513:532–541, 2009. © 2009 Wiley‐Liss, Inc.
Chronic low‐level lead exposure affects the monoaminergic system in the mouse superior olivary complex
Authors: Fortune Tyler , Lurie Diana I. 
Published: February 2009

AbstractLow‐level lead (Pb) exposure is associated with behavioral and cognitive dysfunction, but it is not clear how Pb produces these behavioral changes. Pb has been shown to alter auditory temporal processing in both humans and animals. Auditory temporal processing occurs in the superior olivary complex (SOC) in the brainstem, where it is an important component in sound detection in noisy environments and in selective auditory attention. The SOC receives a serotonergic innervation from the dorsal raphe, and serotonin has been implicated in auditory temporal processing within the brainstem and inferior colliculus. Because Pb exposure modulates auditory temporal processing, the serotonergic system is a potential target for Pb. The current study was undertaken to determine whether developmental Pb exposure preferentially changes the serotonergic system within the SOC. Pb‐treated mice were exposed to no Pb, very low Pb (0.01 mM), or low Pb (0.1 mM) throughout gestation and through 21 days postnatally. Brainstem sections from control and Pb‐exposed mice were immunostained for the vesicular monoamine transporter 2 (VMAT2), serotonin (5‐HT), and dopamine‐β‐hydroxylase (DβH; a marker for norepinephrine) in order to elucidate the effect of Pb on monoaminergic input into the SOC. Sections were also immunolabeled with antibodies to vesicular glutamate transporter 1 (VGLUT1), vesicular γ‐aminobutyric acid (GABA) transporter (VGAT), and vesicular acetylcholine transporter (VAChT) to determine whether Pb exposure alters the glutaminergic, GABAergic, or cholinergic systems. Pb exposure caused a significant decrease in VMAT2, 5‐HT, and DβH expression, whereas VGLUT1, VGAT, and VAChT showed no change. These results provide evidence that Pb exposure during development alters normal monoaminergic expression in the auditory brainstem. J. Comp. Neurol. 513:542–558, 2009. © 2009 Wiley‐Liss, Inc.
Entangling Light in its Spatial Degrees of Freedom with Four‐Wave Mixing in an Atomic Vapor
Authors: Boyer Vincent , Marino Alberto M. , Pooser Raphael C. , Lett Paul D. 
Published: February 2009

AbstractNonlinearities in atomic vaporsallow the production of “entangled images”—beams of light whose transverse light distributions exhibit localized correlations in their unavoidable quantum fluctuations (see picture). These spatially entangled beams may prove useful to reduce the noise in absorption imaging and beam positioning below the quantum noise level, as well as for quantum information applications.magnified imageThe entanglement properties of two beams of light can reside in subtle correlations that exist in the unavoidable quantum fluctuations of their amplitudes and phases. Recent advances in the generation of nonclassical light with four‐wave mixing in an atomic vapor have permitted the production and the observation of entanglement that is localized in almost arbitrary transverse regions of a pair of beams. These multi‐spatial‐mode entangled beams may prove useful for an array of applications ranging from noise‐free imaging and improved position sensing to quantum information processing.
Spectral, Structural, and Computational Studies of a New Family of Ruthenium(II) Complexes Containing Substituted 1,10‐Phenanthroline Ligands and in situ Electropolymerization of a Phenanthrolineruthenium(II) Complex Bridging Nanogap Gold Electrodes
Authors: Huang Wei , Wang Li , Tanaka Hirofumi , Ogawa Takuji 
Published: February 2009

AbstractThe synthesis and spectral and structural characterization of a new family of ruthenium(II) complexes containing 3‐bromo‐, 3,8‐dibromo‐, 3‐(thiophen‐2′,2″‐yl)‐, and 3,8‐(thiophen‐2′,2″‐yl)‐1,10‐phenanthroline (phen) ligands is described. UV/Vis spectroscopy is used to compare the differences between the conjugated π systems in these ligands and their respective [Ru(bpy)2]2+ (bpy = 2,2′‐bipyridine) analogs. Density functional theory (DFT) computations have been carried out to compare the energy differences between the single‐crystal and the energy‐minimized structures for different conformations (trans/trans, trans/cis and cis/cis) of the thiophene rings and their bonded phen ring. The formation of an oligothiophene semiconductor polymer bridging gold electrodes with a gap of around 25 nm gap from RuII complex 7 by in situ electropolymerization, and its removal, is monitored by scanning electron microscopy (SEM). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Regioselective C‐6 Hydrolysis of MethylO‐Benzoyl‐pyranosides Catalysed byCandida RugosaLipase
Authors: Esmurziev Aslan , Sundby Eirik , Hoff Bård Helge 
Published: February 2009

AbstractHydrolysis of six methylO‐benzoyl‐pyranosides has been investigated usingCandida rugosalipase in dioxane/buffer mixtures. The lipase catalysed the hydrolysis of all substrates in a regiospecific manner at C‐6. The rate of reaction was dependent on pyranoside structure, reaction temperature and scale, dioxane concentration and agitation speed. Starting from their C‐6O‐benzoyl precursors, the methyl 2,3,4‐tri‐O‐benzoyl‐pyranosides of α‐D‐galactose, β‐D‐galactose, α‐D‐glucose, and methyl 2,3‐di‐O‐benzoyl‐α‐D‐galactopyranoside could be isolated in 85–96 % yield. In hydrolysis of methyl 2,3,4,6‐tetra‐O‐benzoyl‐α‐D‐glucopyranoside and methyl 2,3,4,6‐tetra‐O‐benzoyl‐β‐D‐galactopyranoside substrate inhibition were observed, which in part could be overcome by increasing the reaction volume. Methyl 2,3,4,6‐tetra‐O‐benzoyl‐β‐D‐glucopyranoside and methyl 2,3,4,6‐tetra‐O‐benzoyl‐α‐D‐mannopyranoside were poor substrates forCandida rugosalipase and low degree of conversion towards products were obtained under all conditions. No acyl migration was detected in any of the products.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
A Novel Galactosyltransferase Inhibitor with Diamino Sugar as a Pyrophosphate Mimic
Authors: Mitsuhashi Nobuyuki , Yuasa Hideya 
Published: February 2009

AbstractConjugates of 2,4‐diamino sugars and uridine have been synthesized as galactosyltransferase inhibitors. The relationship between inhibitory activity and the chelation abilility of the hinge‐like diamino sugar towards a metal ion was studied by NMR spectroscopy. One of the conjugates exhibited a moderate inhibition that ranks between those of UDP and UMP probably through the chelation of the hinge‐like diamino sugar to MnII. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Synthesis of Enantioenriched Secondary and Tertiary Alcohols via Tricarbonylchromium(0) Complexes of Benzyl Allyl Ethers
Authors: Abecassis Keren , Gibson Susan E. , Martin‐Fontecha Mar 
Published: February 2009

AbstractAllyl ethers of the tricarbonylchromium(0) complexes of benzylic alcohols undergo highly enantioselective benzylic functionalisation using a chiral base/electrophilic quench sequence; the allyl group is readily removed to reveal a hydroxy group as demonstrated in the syntheses of enantioenriched imidazole alcohols, a triol and a tertiary alcohol. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
A research on used quantity of ground resistance reduction agent for ground systems
Authors: Chen Li‐Hsiung , Chen Jiann‐Fuh , Liang Tsorng‐Juu , Wang Wen‐I 
Published: February 2009

AbstractThe ground resistance reduction agent can be used to decrease ground resistance for high soil resistivity. The ground resistance decreases and the ground resistance reduction rate increases with increasing quantity of ground resistance reduction agent used. However, the ground resistance reduction effect will display the saturation phenomenon when the quantity of ground resistance reduction agent used increases to a certain level. This research discusses the quantity of ground resistance reduction agent used for ground rod. The used quantity of ground resistance reduction agent should be avoided in saturated areas to maximize the efficiency of ground resistance reduction agent use. Copyright © 2009 John Wiley & Sons, Ltd.
Fluid–solid interaction problems with thermal convection using the immersed element‐free Galerkin method
Authors: Pita Claudio M. , Felicelli Sergio D. 
Published: February 2009

AbstractIn this work, the immersed element‐free Galerkin method (IEFGM) is proposed for the solution of fluid–structure interaction (FSI) problems. In this technique, the FSI is represented as a volumetric force in the momentum equations. In IEFGM, a Lagrangian solid domain moves on top of an Eulerian fluid domain that spans over the entire computational region. The fluid domain is modeled using the finite element method and the solid domain is modeled using the element‐free Galerkin method. The continuity between the solid and fluid domains is satisfied by means of a local approximation, in the vicinity of the solid domain, of the velocity field and the FSI force. Such an approximation is achieved using the moving least‐squares technique. The method was applied to simulate the motion of a deformable disk moving in a viscous fluid due to the action of the gravitational force and the thermal convection of the fluid. An analysis of the main factors affecting the shape and trajectory of the solid body is presented. The method shows a distinct advantage for simulating FSI problems with highly deformable solids. Copyright © 2009 John Wiley & Sons, Ltd.
The symptom profile of vascular depression
Authors: Naarding Paul , Veereschild Mike , Bremmer Marijke , Deeg Dorly , Beekman Aartjan T. F. 
Published: February 2009

AbstractObjectivesVascular depression is regarded as a subtype of depression, especially in––but not limited strictly to––older persons, and characterized by a specific clinical presentation and an association with (cerebro)vascular risk and disease. It is also known that depression is a risk factor in the development of myocardial infarction. The possibility of identifying depressed subjects at risk of a first cardiac event by their clinical presentation in general practice would have significant implications.MethodsWe studied the baseline depression symptom profiles of subjects in the Longitudinal Aging Study Amsterdam and compared the profile of depressed subjects who had and had not suffered a first cardiac event at a follow‐up after eight years.ResultsWe could not confirm the specific symptom profile in depressed subjects who suffered from a first cardiac event at follow‐up. Most notably, the presumed specific symptoms of vascular depression, psychomotor retardation, and anhedonia were not significantly associated with the occurrence of a first cardiac event at follow‐up.ConclusionsIn this large community study we failed to identify a difference in the depression symptom profile between incident cardiac and non‐cardiac cases. Copyright © 2009 John Wiley & Sons, Ltd.
Primary care and dementia: 1. diagnosis, screening and disclosure
Authors: Iliffe Steve , Robinson Louise , Brayne Carol , Goodman Claire , Rait Greta , Manthorpe Jill , Ashley Peter 
Published: February 2009

AbstractObjectivesTo write a narrative review of the roles of primary care practitioners in caring for people with dementia in the community.MethodsThe systematic review carried out for the NICE/SCIE Guidelines was updated from January 2006, Cochrane Reviews were identified, and other publications found by consultation with experts.ResultsThe insidious and very variable development of dementia syndromes makes recognition of the syndrome problematic in primary care. Dementia is probably under‐diagnosed and under treated with an estimated 50% of primary care patients over 65 not diagnosed by their primary care physicians. This problem of under‐diagnosis is probably not due to lack of diagnostic skills, but rather to the interaction of case‐complexity, pressure on time and the negative effects of reimbursement systems. Primary care physicians often over‐estimate the prevalence of dementia syndromes, but in some countries may also overestimate the prevalence of vascular dementia compared with Alzheimer's disease. Diagnosis is a step‐wise process which can be aided by use of a cognitive function test, of which there are a number suitable for primary care use. Evidence based practice protocols can enhance detection rates in primary care, and there is growing evidence that communication skills in talking to people with dementia about dementia can be improved. Nevertheless there are multiple obstacles to bringing recognition forward in time, both in public awareness and professional understanding of the early changes in dementia.ConclusionsThere is insufficient evidence of benefit to justify population screening in primary care but earlier recognition of people with dementia syndrome is possible within primary care. The diagnosis of dementia is a shared responsibility between generalist and specialist disciplines. Primary care physicians should explore patients' ideas and concerns around their symptoms prior to referral and tentatively discuss possible diagnoses. Once the diagnosis has been confirmed, the primary care physician should provide both practical and emotional support to allow the patient and their family to come to terms with living with dementia, and refer them for additional psychosocial support if required. Copyright © 2009 John Wiley & Sons, Ltd.
The moderating role of personality factors in the relationship between depression and neuropsychological functioning among older adults
Authors: Ayotte Brian J. , Potter Guy G. , Williams Heather T. , Steffens David C. , Bosworth Hayden B. 
Published: February 2009

AbstractObjectiveDepression is often associated with decreased cognitive performance among older adults. The current study focused on the association of neuropsychological functioning and personality traits in depressed and non‐depressed older adults.MethodsData from 75 depressed and 103 non‐depressed adults over the age of 60 were analyzed. All participants underwent standardized clinical assessment for depression prior to participation and completed the NEO‐PI‐R and a series of neuropsychological assessments.ResultsA series of multiple linear regressions were conducted to examine the relationships between personality and neuropsychological performance among depressed and non‐depressed older adults. Results indicated that higher Openness to Experience was related to better performance on Parts A and B of the Trail Making Test among depressed older adults, and to better Digit Span Backward performance among all participants. Higher levels of neuroticism were related to poorer performance on Digit Span Backward, but only among depressed older adults. Depressed participants performed more poorly on the Symbol Digit Modalities Test and the Controlled Oral Word Association Test.ConclusionsPersonality characteristics, particularly Openness to Experience, modified the relationship between depression and neuropsychological functioning among older adults. Results indicate that interventions aimed at increasing one's Openness to Experience could potentially attenuate some of the neuropsychological impairments that are associated with depression. Copyright © 2009 John Wiley & Sons, Ltd.