bluuebunny/crossref_metadata_2025 huggingface dataset:
Apolipoprotein E–dependent accumulation of Alzheimer disease–related lesions begins in middle age
Authors: Kok Eloise , Haikonen Satu , Luoto Teemu , Huhtala Heini , Goebeler Sirkka , Haapasalo Hannu , Karhunen Pekka J.
Published: June 2009

Objective

To study the prevalence and age dependency of senile plaques (SP) and neurofibrillary tangles (NFT), the brain changes characteristic of Alzheimer disease (AD), and their association with apolipoprotein E (APOE) genotypes in a community‐dwelling normal population.

Methods

This neuropathological study used both silver staining and Aβ immunohistochemistry in brain tissue microarrays, including SP coverage and NFT counts from frontal cortex and hippocampus, and APOE genotyping, and was performed on a consecutive prospective series of 603 subjects (aged between 0 and 97 years) of an unselected population living outside of institutions. Cases were subjected to autopsy following sudden or unexpected out‐of‐hospital death, covering 22.1% of the mortality of Tampere, Finland and its surroundings. None died of AD, although 22 (3.7%) were demented and 10 (1.7%) had memory problems.

Results

Of the series, 30.8% had SP, and 42.1% had NFT; these occurred more commonly among females and showed a strong relationship with age. Both changes had already appeared at around 30 years of age, reaching an occurrence of almost 100% in the oldest. SP were more frequent in APOE ϵ4‐carriers compared with noncarriers in every age group except the oldest (>90 years). The difference was most evident during the ages 50 to 59 years, where 40.7% of ϵ4‐carriers had SP, compared with 8.2% in noncarriers (odds ratio, 8.39; 95% confidence interval, 2.55–27.62). The difference in NFT prevalence between APOE genotypes was not statistically significant in any age group.

Interpretation

The brain changes associated with AD may already begin developing early in middle age, especially among APOE ϵ4 carriers. Ann Neurol 2009;65:650–657
Palladium(II)‐katalysierte C‐H‐Aktivierung/C‐C‐Kreuzkupplung: Vielseitigkeit und Anwendbarkeit
Authors: Chen Xiao , Engle Keary M. , Wang Dong‐Hui , Yu Jin‐Quan
Published: June 2009

Katalyse mit Methode: Eine ganze Reihe katalytischer Palladiumsysteme für die C‐H‐Aktivierung/C‐C‐Kupplung (siehe Schema) wurde in jüngerer Zeit entwickelt. Ein besonderer Schwerpunkt ist die PdII‐katalysierte Kupplung von C‐H‐Bindungen mit metallorganischen Reagentien durch PdII/Pd0‐Katalysezyklen. Die Vielseitigkeit dieser Katalysemethode wird demonstriert, zudem werden offene Fragen sowie das Entwicklungspotenzial des Gebietes angesprochen.

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In den letzten zehn Jahren wurde die palladiumkatalysierte C‐H‐Aktivierung/C‐C‐Kupplung zu einer vielversprechenden katalytischen Umwandlung entwickelt. Allerdings sind die Möglichkeiten auf diesem Gebiet bisher noch nicht so umfangreich wie bei den Kreuzkupplungen, bei denen Aryl‐ und Alkylhalogenide eingesetzt werden. Dieser Aufsatz stellt vier ausführlich untersuchte Katalysemethoden zur C‐C‐Bindungsbildung ausgehend von C‐H‐Bindungen vor: PdII/Pd0‐, PdII/PdIV‐, Pd0/PdII/PdIV‐ und Pd0/PdII‐Katalyse. Außerdem werden neuere Entwicklungen bei der PdII‐katalysierten Kupplung von C‐H‐Bindungen mit metallorganischen Reagentien durch einen PdII/Pd0‐Katalysezyklus vorgestellt. Ungeachtet aller bisherigen Fortschritte verbleibt es eine wichtige Aufgabe, die Vielseitigkeit und Anwendbarkeit dieser Reaktionen auf eine breitere Grundlage zu stellen.
Titelbild: Spectroscopic Tracking of Molecular Transport Junctions Generated by Using Click Chemistry (Angew. Chem. 28/2009)
Authors: Chen Xiaodong , Braunschweig Adam B. , Wiester Michael J. , Yeganeh Sina , Ratner Mark A. , Mirkin Chad A.
Published: June 2009

Die In‐situ‐Erzeugung von Molekülbrücken über Nanolücken, die durch “On‐Wire”‐Lithographie erzeugt wurden, gelingt mithilfe der Klickchemie. C. A. Mirkin et al. zeigen in der Zuschrift auf S. 5280 ff., dass diese molekularen Kontakte in hohen Ausbeuten entstehen, und schildern, wie das Verfahren für eine Vielfalt von Molekülarchitekturen verallgemeinert werden kann. Die molekulare Selbstorganisation in den Nanolücken lässt sich dank ihres starken elektromagnetischen Feldes verfolgen.

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Inside Cover: Adsorption, Diffusion, and Self‐Assembly of an Engineered Gold‐Binding Peptide on Au(111) Investigated by Atomic Force Microscopy (Angew. Chem. Int. Ed. 28/2009)
Authors: So Christopher R. , Tamerler Candan , Sarikaya Mehmet
Published: June 2009

The binding, diffusion, and aggregation mechanism of an engineered binding peptide on Au(111), showing non‐equilibrium surface structures that lead to the formation of a confluent monolayer, is described by M. Sarikaya et al. in their Communication on page 5174 ff. The observed dynamic structural evolution involving the surface diffusion of peptides and multiple stages of molecular thin film topology are explained. Ersin Emre Oren is thanked for the design of the graphic.

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Cationization of cellulose by using N‐oxiranylmethyl‐N‐methylmorpholinium chloride and 2‐oxiranylpyridine as etherification agents
Authors: Hasani Merima , Westman Gunnar , Potthast Antje , Rosenau Thomas
Published: June 2009

Cationization of cellulose under aqueous alkaline conditions was studied. Two new epoxy reagents, N‐oxiranylmethyl‐N‐methylmorpolinium chloride and 2‐oxiranylpyridine, were used for preparation of cationic cellulose ethers. Using the first agent, cationic ethers were obtained in one step, whereas the latter one yielded a reactive intermediate used as a precursor for two different cationizations. Etherification with the commonly used 2,3‐epoxypropyltrimethylammonium chloride was also performed and used as a reference reaction. By changing water content in the reaction mixture two groups cellulose ethers with different degrees of cationization were prepared. As expected, reducing the water content resulted in a higher degree of etherification and hence a more pronounced cationic character of the obtained ethers. Characterization by FTIR, elemental‐ and gravimetric analysis confirmed the formation of the desired ethers. Their ability to interact with water and adsorb the acid dye, methyl orange, was also studied, confirming further introduction of the cationic substituents and revealing different reactivities of the used epoxy reagents. From characterization, it could be concluded that N‐oxiranylmethyl‐N‐methylmorpholinium chloride exhibits higher reactivity toward cellulose than both the reference compounds and 2‐oxiranylpyridine. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Expression, purification, and characterization of pro‐phenoloxidase‐activating serine protease from Spodoptera litura
Authors: Arora Naresh , Hoque M. E. , Rajagopal R. , Sachdev Bindiya , Bhatnagar Raj K.
Published: June 2009

One of the important trigger molecules for innate immunity is a serine protease that activates zymogen phenol oxidase (PPO). Central to wound healing response is the activation of phenol oxidase zymogen. Molecular characterization of phenol oxidase has been recently reported by us. Here, we report isolation, cloning, expression, and purification of prophenol oxidase activating enzyme 1 (slppae1) from polyphagous pest, Spodoptera litura. SLPPAE1 is induced within 6 h of physical injury. The structural features of the mature polypeptide are reminiscent of other lepidopteran PPAE in having a signal peptide, propeptide, and catalytically active polypeptide. The cDNA has been expressed in Sf21 cells using baculovirus expression vector. Fractionation of expressing Sf21 cells revealed its expression in the membranes. The recombinant protein was solubilized from membranes and purified by Ni‐NTA affinity chromatography. The purified enzyme is catalytically active on chromogenic substrate, activates recombinantly expressed prophenol oxidase (PPO) of S. litura, and is sensitive to inhibition by aprotenin. N‐terminal sequencing of processed phenol oxidase revealed 11 kDa propeptide instead of in‐silico predicted 6 kDa polypeptide. © 2009 Wiley Periodicals, Inc.
Hemolymph ecdysteroids during the last three molt cycles of the blue crab, Callinectes sapidus: quantitative and qualitative analyses and regulation
Authors: Chung J. Sook
Published: June 2009

The profiles of circulating ecdysteroids during the three molt cycles prior to adulthood were monitored from the juvenile blue crab, Callinectes sapidus. Ecdysteroid patterns are remarkably similar in terms of peak concentrations ranging between 210–330 ng/ml hemolymph. Analysis of hemolymph at late premolt stage revealed six different types of ecdysteroids with ponasterone A (PoA) and 20‐OH ecdysone (20‐OH E) as the major forms. This ecdysteroid profile was consistent in all three molt cycles. Bilateral eyestalk ablation (EA) is a procedure that removes inhibitory neurohormones including crustacean hyperglycemic hormone (CHH) and molt‐inhibiting hormone (MIH) and often results in precocious molting in crustaceans. However, the inhibitory roles of these neuropeptides in vivo have not yet been tested in C. sapidus. We determined the regulatory roles of CHH and MIH in the circulating ecdysteroid from ablated animals through daily injection. A daily administration of purified native CHH and MIH at physiological concentration maintained intermolt levels of ecdysteroids in the EA animals. This suggests that Y organs (YO) require a brief exposure to CHH and MIH in order to maintain the low level of ecdysteroids. Compared to intact animals, the EA crabs did not exhibit the level of peak ecdysteroids, and the major ecdysteroid turned out to be 20‐OH E, not PoA. These results further underscore the important actions of MIH and CHH in ecdysteroidogenesis, as they not only inhibit, but also control the composition of output of the YO activity. © 2009 Wiley Periodicals, Inc.
Polyunsaturated fatty acids inhibit PI3K activity in a yeast‐based model system
Authors: Couplan Elodie , Le Cann Marie , Le Foll Christelle , Corporeau Charlotte , Blondel Marc , Delarue Jacques
Published: June 2009

The phosphatidylinositol 3‐kinase (PI3K) pathway controls the regulation of cell growth, proliferation, migration and apoptosis. In many tumors, the PI3K gene is mutated or overexpressed, and/or the PI3K pathway is hyperactive. PI3K is therefore a potential pharmacological target for the development of anti‐tumor drugs. Some polyunsaturated fatty acids (PUFA), when given in the diet, may lead to a decrease in PI3K activity. We used a yeast‐based model to reconstitute the PI3K/PTEN/Akt pathway to study the effects of long‐chain polyunsaturated n‐3 fatty acids on PI3K, and found that various PUFA were able to alleviate toxicity induced by overexpression of PI3K. The various PUFA had no significant effect on the steady‐state level of PI3K catalytic subunit proteins (p110α) in yeast. However, depletion of phosphatidylinositol 4,5‐bisphosphate due to overexpression of the p110α subunit was significantly reduced by treating the yeast cells with the various PUFA. The inhibition of mammalian PI3K, expressed in an exogenous cellular context in yeast, is likely to be a direct effect of these PUFA on PI3K rather than on other mammalian endogenous or environmental factors. These results are particularly promising given the abundance of active PUFA in marine foodstuffs and especially fish oils.
Cloning and overexpression of a thermostable signal peptide peptidase (SppA) from Thermoplasma volcanium GSS1 in E. coli
Authors: Kocabıyık Semra , Demirok Burçak
Published: June 2009

In this study, a gene coding for thermophilic serine protease of the ClpP class from the thermoacidophilic archaeon Thermoplasma volcanium (Tpv) was cloned and expressed in Escherichia coli. The primary sequence and domain analysis of this enzyme showed similarities (50–60% similarity) to signal peptide peptidases (SppA) of bacteria and other archaea. An increase of about tenfold in the activity was achieved by overexpression of Tpv SppA in E. coli, as detected by enzyme assays conducted using Ala‐Ala‐Phe‐pNa and N‐Suc‐Ala‐Ala‐Pro‐Phe‐pNA as substrates. The recombinant enzyme, purified using an anion exchange column chromatography, displayed an apparent molecular mass of 26 kDa on SDS‐PAGE analysis. Purified Tpv SppA was active in a broad range of pH and temperature with maximal activity at 60°C and between pH 7.5 and pH 8.0. The activity of the enzyme was strongly inhibited by inhibitors typical for serine proteases, i.e., chymostatin and PMSF. The activity of the Tpv SppA and the stability at high temperature were significantly enhanced in the presence of 5 mM Ca2+ ions. Our multiple sequence alignment data revealed a conserved Ser/Lys catalytic dyad in Tpv SppA that comprised Ser76 (nucleophile) and Lys128 (general base) residues. A search for a transmembrane domain using automated programs did not predict any signal peptide associated with the Tpv SppA and, therefore, suggested a cytoplasmic location for this enzyme.
Metals sorption from aqueous solutions by Kluyveromyces marxianus: Process optimization, equilibrium modeling and chemical characterization
Authors: Pal Rama , Tewari Saumyata , Rai Jai P. N.
Published: June 2009

The dead Kluyveromyces marxianus biomass, a fermentation industry waste, was used to explore its sorption potential for lead, mercury, arsenic, cobalt, and cadmium as a function of pH, biosorbent dosage, contact time, agitation speed, and initial metal concentration. The equilibrium data fitted the Langmuir model better for cobalt and cadmium, but Freundlich isotherm for all metals tested. At equilibrium, the maximum uptake capacity (Qmax) was highest for lead followed by mercury, arsenic, cobalt, and cadmium. The RL values ranged between 0–1, indicating favorable sorption of all test metals by the biosorbent. The maximum Kf value of Pb showed its efficient removal from the solution. However, multi‐metal analysis depicted that sorption of all metals decreased except Pb. The potentiometric titration of biosorbent revealed the presence of functional groups viz. amines, carboxylic acids, phosphates, and sulfhydryl group involved in heavy metal sorption. The extent of contribution of functional groups and lipids to biosorption was in the order: carboxylic>lipids>amines>phosphates. Blocking of sulfhydryl group did not have any significant effect on metal sorption.
A putative role for human BFK in DNA damage‐induced apoptosis
Authors: Özören Nesrin , Inohara Naohiro , Núñez Gabriel
Published: June 2009

Human BFK (BCL‐2 family kin) is a novel pro‐apoptotic BCL‐2 family member specifically expressed in the gastrointestinal tract. BFK has the characteristic BH3 domain, which was shown to be essential for the apoptosis‐inducing activity of pro‐apoptotic BCL‐2 family members. When overexpressed, BFK interacts with BCL‐XL and BCL‐W but not BCL‐2 or BAD in co‐immunoprecipitations studies. We find that BFK exhibits striking similarity to BID in the way it is activated through cleavage during apoptosis. The endogenous and cleaved versions of BFK are readily recognized by the rabbit and mouse sera raised against human BFK. An ideal caspase 3 or 7 target sequence, DEVD (amino acids 38–41), is evident N‐terminal to the BH3 domain. A recombinant version of the protein containing all residues downstream of the putative caspase cleavage site induces apoptosis in human colon cancer cells, HCT116, and in wild‐type mouse embryonic fibroblasts (MEFs), which can be reversed by co‐expression of BCL‐XL or BCL‐W. BFK becomes activated through caspase‐dependent cleavage during DNA damage‐induced apoptosis. The cleaved form of the protein is dependent on the presence of BAX or BAK for its ability to induce apoptosis, since BAX–/–‐BAK–/– double‐knockout MEFs are completely resistant to BFK‐induced apoptosis.
Using microarray technology to select housekeeping genes in Chinese hamster ovary cells
Authors: Bahr Scott M. , Borgschulte Trissa , Kayser Kevin J. , Lin Nan
Published: June 2009

In the present study, we have identified species‐specific housekeeping genes (HKGs) for Chinese Hamster Ovary (CHO) cells using data from microarray gene expression profiling. HKGs suitable for quantitative RT‐PCR normalization should display relatively stable expression levels across experimental conditions. We analyzed transcription profiles of several IgG‐producing recombinant CHO cell lines under numerous culture conditions using a custom CHO DNA microarray platform and calculated relative expression variability from 124 microarrays. We selected a novel panel of candidate HKGs based on their low variability in expression from the microarray data. Compared to three traditional HKGs (Gapdh, Actb, and B2m), the majority of genes on this panel demonstrated lower or equal variability. Each candidate HKG was then validated using qRT‐PCR. Final selection of CHO‐specific HKGs include Actr5, Eif3i, Hirip3, Pabpn1, Vezt, Cog1, and Yaf2. The results reported here provide a useful tool for gene expression analyses in CHO cells, a critical expression platform used in biotherapeutics. Biotechnol. Bioeng. 2009; 104: 1041–1046. © 2009 Wiley Periodicals, Inc.
Noncovalent Modulation of pH‐Dependent Reactivity of a Mn–Salen Cofactor in Myoglobin with Hydrogen Peroxide
Authors: Zhang Jun‐Long , Garner Dewain K. , Liang Lei , Barrios David A. , Lu Yi
Published: June 2009

To demonstrate protein modulation of metal‐cofactor reactivity through noncovalent interactions, pH‐dependent sulfoxidation and 2,2′‐azino‐bis(3‐ethylbenzthiazoline‐6‐sulphonic acid) (ABTS) oxidation reactivity of a designed myoglobin (Mb) containing non‐native Mn–salen complex (1) was investigated using H2O2 as the oxidant. Incorporation of 1 inside the Mb resulted in an increase in the turnover numbers through exclusion of water from the metal complex and prevention of Mn–salen dimer formation. Interestingly, the presence of protein in itself is not enough to confer the increase activity as mutation of the distal His64 in Mb to Phe to remove hydrogen‐bonding interactions resulted in no increase in the turnover numbers, while mutation His64 to Arg, another residue with ability to hydrogen‐bond interactions, resulted in an increase in reactivity. These results strongly suggest that the distal ligand His64, through its hydrogen‐bonding interaction, plays important roles in enhancing and fine‐tuning reactivity of the Mn–salen complex. Nonlinear least‐squares fitting of rate versus pH plots demonstrates that 1⋅Mb(H64X) (X=H, R and F) and the control Mn–salen 1 exhibit pKa values varying from pH 6.4 to 8.3, and that the lower pKa of the distal ligand in 1⋅Mb(H64X), the higher the reactivity it achieves. Moreover, in addition to the pKa at high pH, 1⋅Mb displays another pKa at low pH, with pKa of 5.0±0.08. A comparison of the effect of different pH on sulfoxidation and ABTS oxidation indicates that, while the intermediate produced at low pH conditions could only perform sulfoxidation, the intermediate at high pH could oxidize both sulfoxides and ABTS. Such a fine‐control of reactivity through hydrogen‐bonding interactions by the distal ligand to bind, orient and activate H2O2 is very important for designing artificial enzymes with dramatic different and tunable reactivity from catalysts without protein scaffolds.
Stanislao Cannizzaro and the Development of Chemistry in Palermo from 1862 to 1871
Authors: Zingales Roberto
Published: June 2009

Stanislao Cannizzaro worked at Palermo University for about ten years. There he managed to establish a modern and well‐equipped chemical laboratory. His international fame attracted co‐workers even from abroad: Naquet, Lieben, and Körner came to Palermo to work with him. This greatly improved the quality of teaching and of research in Palermo, which became a worldwide acknowledged center of chemical culture. In Palermo, atomic‐molecular theory was extensively taught and research was carried out on chemical atomicity (valence) and spatial structures of both aliphatic and aromatic organic molecules: Körner found the relative positions of substituent groups on the benzene ring, Paternò proved the equivalence of the four positions around each carbon atom. Thanks to Cannizzaro′s and Paternò′s efforts, a new journal, Gazzetta Chimica Italiana, was printed in Palermo. The journal collected original papers from Italian chemists, and summaries or translations of foreign ones. When Cannizzaro moved to Rome in 1872, Emanuele Paternò, the youngest of his pupils, took his place. Eventually, Paternò also moved to Rome, and the leading role of Palermo in Italian chemistry faded.
Photophysics of an Intramolecular Hydrogen‐Evolving Ru–Pd Photocatalyst
Authors: Tschierlei Stefanie , Presselt Martin , Kuhnt Christian , Yartsev Arkady , Pascher Torbjörn , Sundström Villy , Karnahl Michael , Schwalbe Matthias , Schäfer Bernhard , Rau Sven , Schmitt Michael , Dietzek Benjamin , Popp Jürgen
Published: June 2009

Photoinduced electron‐transfer processes within a precatalyst for intramolecular hydrogen evolution [(tbbpy)2Ru(tpphz)PdCl2]2+(RuPd; tbbpy=4,4′‐di‐tert‐butyl‐2,2′‐bipyridine, tpphz=tetrapyrido[3,2‐a:2′,3′c:3′′,2′′,‐h:2′′′,3′′′‐j]phenazine) have been studied by resonance Raman and ultrafast time‐resolved absorption spectroscopy. By comparing the photophysics of the [(tbbpy)2Ru(tpphz)]2+subunitRuwith that of the supramolecular catalystRuPd, the individual electron‐transfer steps are assigned to kinetic components, and their dependence on solvent is discussed. The resonance Raman data reveal that the initial excitation of the molecular ensemble is spread over the terminal tbbpy and the tpphz ligands. The subsequent excited‐state relaxation of bothRuandRuPdon the picosecond timescale involves formation of the phenazine‐centered intraligand charge‐transfer state, which inRuPdprecedes formation of the Pd‐reduced state. The photoreaction in the heterodinuclear supramolecular complex is completed on a subnanosecond timescale. Taken together, the data indicate that mechanistic investigations must focus on potential rate‐determining steps other than electron transfer between the photoactive center and the Pd unit. Furthermore, structural variations should be directed towards increasing the directionality of electron transfer and the stability of the charge‐separated states.
Treatment of Terminal Alkynes R–C≡C–H with Dialkylaluminum Hydrides: Hydroalumination versus Deprotonation
Authors: Uhl Werner , Er Elif , Hepp Alexander , Kösters Jutta , Layh Marcus , Rohling Martina , Vinogradov Andrej , Würthwein Ernst‐Ulrich , Ghavtadze Nugzar
Published: June 2009

Dialkylaluminum hydrides R2Al–H (R = Me, Et, iBu, CH2tBu, tBu), reacted with tert‐butylethyne, H–C≡C–CMe3, by hydroalumination and formation of the corresponding vinylic compounds, R2Al–C(H)=C(H)–CMe3. The products are dimeric in the solid state with the negatively charged vinylic carbon atoms in the bridging positions and adopt usually a centrosymmetric structure with the C=C double bonds on different sides of the central Al2C2 heterocycle. Only with R = Me the C2v structure with the cis arrangement of the alkenyl groups was found. Complicated mixtures of isomeric substances were detected in solution. Quantum‐chemical calculations revealed a considerable charge separation in the C=C double bonds of the dimeric formula units. The α‐carbon atoms coordinated by both aluminum atoms show high negative NBO charges of about –1.0, while the β‐carbon atoms are almost uncharged (0.0 to –0.1). The rotational barriers decreased upon dimerization. Hence, the formation of such dimers may be the key step in the well‐known cis/trans isomerization process of hydroalumination and hydrogallation products. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Mononuclear and Dinuclear NiII and CuII Complexes with a Pyrrolecarboxamide Ligand: Core Conversions and Unusual Presence of a Dimer and Two Monomers in the Same Unit Cell
Authors: Singh Jyoti , Hundal Geeta , Gupta Rajeev
Published: June 2009

A potential tetradentate pyrrolecarboxamide ligand, H4L1, coordinates to metal ions (M = Ni or Cu) either in tetraanionic or trianionic fashion to afford mononuclear [M(L1)]2–, dinuclear [M2(HL1)2]2–, or adduct [{M2(HL1)2}{M(L1)}2]6– complexes, respectively. The dinuclear complexes can be converted into the mononuclear complexes by the addition of NaOH due to the presence of protonated sites. On the other hand, Cu‐monomer can be converted into the Cu adduct after treating with water. Interestingly, the crystal structure of the adduct shows the unusual presence of a Cu2‐dimer and two Cu‐monomers in the same unit cell. The structure shows extensive network of H‐bonds between the Cu2‐dimer and Cu‐monomers through two water molecules. Further, this adduct can be assembled by mixing isolated one mole of Cu2‐dimer and two moles of Cu‐monomers. Crystallographic studies depict several interesting weak interactions in these complexes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Semi In Situ Synthesis of NHTS: A New Hollow Titanium Silicalite Modified by a Noble Metal
Authors: Shi Chunfeng , Zhu Bin , Lin Min , Long Jun
Published: June 2009

A new hollow titanium silicalite with a noble metal incorporated into it (denoted as NHTS) was synthesized by a semi in situ method. This NHTS has intraparticle voids and exhibits bifunctional catalytic performance. It was characterized by various techniques, and its catalytic performance for the direct epoxidation of propylene was investigated. The results show that NHTS, with a highly ordered MFI topological and hollow structure, together with a noble metal, can be employed in catalytic oxidations.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
One‐Dimensional Coordination Polymers of MnII, CuII, and ZnII Supported by Carboxylate‐Appended (2‐Pyridyl)alkylamine Ligands – Structure and Magnetism
Authors: Arora Himanshu , Lloret Francesc , Mukherjee Rabindranath
Published: June 2009

Four new complexes [MnII(L1OO)(H2O)][ClO4]·2H2O (1), [ZnII(L1OO)][ClO4]·2H2O (2), [CuII(L3OO)][CF3SO3]·H2O (3), and [ZnII(L3OO)][ClO4] (4) (L1OO– = 3‐[(2‐(pyridine‐2‐yl)ethyl){2‐(pyridine‐2‐yl)methyl}amino]propionate; L3OO– = 3‐[(2‐(pyridine‐2‐yl)ethyl){(dimethylamino)ethyl}amino]propionate) have been synthesized and characterized by elemental analysis, IR, and UV/Vis spectroscopy. Structural analysis revealed that 1, 3, and 4 are one‐dimensional chain‐like coordination polymers. In 1 distorted octahedral MnN3O3 and in 3 square‐pyramidal CuN3O2 coordination is satisfied by three nitrogen atoms and an appended carboxylate oxygen atom of the ligand, and an oxygen atom belonging to the carboxylate group of an adjacent molecule. In 4 trigonal bipyramidal ZnN3O2 coordination environment is provided by two nitrogen atoms and an appended carboxylate oxygen atom of the ligand in the equatorial plane, and the two axial positions are satisfied by a tertiary amine nitrogen and an oxygen atom belonging to the carboxylate group of an adjacent molecule. In 1 the MnII center is coordinated by an additional water molecule. In these complexes each monomeric unit is sequentially connected by syn‐anti carboxylate bridges. Temperature‐dependent magnetic susceptibilities for 1 and 3 are measured, revealing antiferromagnetic interactions through syn‐anti carboxylate bridges between the MII centers. Analysis of the crystal packing diagram reveals that in 1 extensive π–π stacking involving alternate pyridine rings of adjacent 1D chain exists, which eventually lead to the formation of a 2D network structure. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Single‐marker and two‐marker association tests for unphased case‐control genotype data, with a power comparison
Authors: Kim Sulgi , Morris Nathan J. , Won Sungho , Elston Robert C.
Published: June 2009

In case‐control single nucleotide polymorphism (SNP) data, the allele frequency, Hardy Weinberg Disequilibrium, and linkage disequilibrium (LD) contrast tests are three distinct sources of information about genetic association. While all three tests are typically developed in a retrospective context, we show that prospective logistic regression models may be developed that correspond conceptually to the retrospective tests. This approach provides a flexible framework for conducting a systematic series of association analyses using unphased genotype data and any number of covariates. For a single stage study, two single‐marker tests and four two‐marker tests are discussed. The true association models are derived and they allow us to understand why a model with only a linear term will generally fit well for a SNP in weak LD with a causal SNP, whatever the disease model, but not for a SNP in high LD with a non‐additive disease SNP. We investigate the power of the association tests using real LD parameters from chromosome 11 in the HapMap CEU population data. Among the single‐marker tests, the allelic test has on average the most power in the case of an additive disease, but for dominant, recessive, and heterozygote disadvantage diseases, the genotypic test has the most power. Among the four two‐marker tests, the Allelic‐LD contrast test, which incorporates linear terms for two markers and their interaction term, provides the most reliable power overall for the cases studied. Therefore, our result supports incorporating an interaction term as well as linear terms in multi‐marker tests. Genet. Epidemiol. 34:67–77, 2010. © 2009 Wiley‐Liss, Inc.
Neuronal activity rapidly induces transcription of the CREB‐regulated microRNA‐132, in vivo
Authors: Nudelman Aaron S. , DiRocco Derek P. , Lambert Talley J. , Garelick Michael G. , Le Josh , Nathanson Neil M. , Storm Daniel R.
Published: June 2009

Activity‐dependent changes in gene‐expression are believed to underlie the molecular representation of memory. In this study, we report that in vivo activation of neurons rapidly induces the CREB‐regulated microRNA miR‐132. To determine if production of miR‐132 is regulated by neuronal activity its expression in mouse brain was monitored by quantitative RT‐PCR (RT‐qPCR). Pilocarpine‐induced seizures led to a robust, rapid, and transient increase in the primary transcript of miR‐132 (pri‐miR‐132) followed by a subsequent rise in mature microRNA (miR‐132). Activation of neurons in the hippocampus, olfactory bulb, and striatum by contextual fear conditioning, odor‐exposure, and cocaine‐injection, respectively, also increased pri‐miR‐132. Induction kinetics of pri‐miR‐132 were monitored and found to parallel those of immediate early genes, peaking at 45 min and returning to basal levels within 2 h of stimulation. Expression levels of primary and mature‐miR‐132 increased significantly between postnatal Days 10 and 24. We conclude that miR‐132 is an activity‐dependent microRNA in vivo, and may contribute to the long‐lasting proteomic changes required for experience‐dependent neuronal plasticity. © 2009 Wiley‐Liss, Inc.
Glass ionomer cement hardness after different materials for surface protection
Authors: Brito Cecilia R. , Velasco Leandro G. , Bonini Gabriela A. V. C. , Imparato José Carlos P. , Raggio Daniela P.
Published: June 2009

The aim of the present study was to evaluate the Knoop hardness of high viscous glass ionomer cement (GIC) Ketac™ Molar Easy Mix (3M ESPE, Saint Paul, USA) submitted to different types of compounds for surface protection. Sixty specimens of GIC were made in PVC molds with 7.5 mm diameter and 2.5 mm thickness. Divided in 6 groups: G1, Control (no protection); G2, Cavitine® (Copal varnish); G3, Magic® bond (Adhesive); G4, Adper™ Single Bond 2 (Single bottle adhesive); G5, Solid Petroleum Jelly; G6, Nail Varnish. The surface protection was applied after initial setting reaction. The specimens were immersed in deionized water, at 37°C, for 24 h. The surfaces were polished in a rotation machine (Aropol 2V). The hardness test was accomplished in a Digital Microhardness tester HVS‐100. In each specimen five indentations were done and repeated after 30 days and 4 months, under the same conditions. The results were submitted to Two‐way ANOVA and Tukey Test. The only material that differed from the control group was the nail varnish (p < 0.001), with the other materials showing no significant difference from the control group. It was concluded that the best material for surface protection of GIC was the nail varnish, but because of possible harmful effects, petrolleum jelly could be a better option. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2010
The performance of dental pulp stem cells on nanofibrous PCL/gelatin/nHA scaffolds
Authors: Yang Xuechao , Yang Fang , Walboomers X. Frank , Bian Zhuan , Fan Mingwen , Jansen John A.
Published: June 2009

The aim of current study is to investigate the in vitro and in vivo behavior of dental pulp stem cells (DPSCs) seeded on electrospun poly(ε‐caprolactone) (PCL)/gelatin scaffolds with or without the addition of nano‐hydroxyapatite (nHA). For the in vitro evaluation, DNA content, alkaline phosphatase (ALP) activity and osteocalcin (OC) measurement showed that the scaffolds supported DPSC adhesion, proliferation, and odontoblastic differentiation. Moreover, the presence of nHA upregulated ALP activity and promoted OC expression. Real‐time PCR data confirmed these results. SEM micrographs qualitatively confirmed the proliferation and mineralization characteristics of DPSCs on both scaffolds. Subsequently, both scaffolds seeded with DPSCs were subcutaneously implanted into immunocompromised nude mice. Scaffolds with nHA but without cells were implanted as control. Histological evaluation revealed that all implants were surrounded by a thin fibrous tissue capsule without any adverse effects. The cell/scaffold composites showed obvious in vivo hard tissue formation, but there was no sign of tissue ingrowth. Further, the combination of nHA in scaffolds did upregulate the expression of specific odontogenic genes. In conclusion, the incorporation of nHA in nanofibers indeed enhanced DPSCs differentiation towards an odontoblast‐like phenotype in vitro and in vivo. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2010
Polymeric matrix for drug delivery: Honokiol‐loaded PCL‐PEG‐PCL nanoparticles in PEG‐PCL‐PEG thermosensitive hydrogel
Authors: Gou MaLing , Gong ChangYang , Zhang Juan , Wang XiuHong , Wang XianHuo , Gu YingChun , Guo Gang , Chen LiJuan , Luo Feng , Zhao Xia , Wei YuQuan , Qian ZhiYong
Published: June 2009

In this article, we demonstrated a novel injectable polymer matrix: honokiol (HK) loaded poly (ϵ‐caprolactone)‐poly(ethylene glycol)‐poly(ϵ‐caprolactone) (PCL‐PEG‐PCL, PCEC) nanoparticles in thermosensitive poly(ethylene glycol)‐poly(ϵ‐caprolactone)‐poly(ethylene glycol) (PEG‐PCL‐PEG, PECE) hydrogel for the drug local delivery. First, HK, as a model hydrophobic drug, was loaded into PCL‐PEG‐PCL nanoparticles by emulsion solvent evaporation method to overcome its poor water solubility. Then, the HK‐loaded PCEC nanoparticles (HK‐PCEC) were incorporated into thermosensitive PEG‐PCL‐PEG hydrogel, which was sol at low temperature and could gel as a depot for sustained release of drug in situ after topical injection. The HK‐PCEC incorporated PECE hydrogel (HK‐PCEC‐PECE) was biodegradable and could be gradually eliminated from the injection site in about 2 weeks after subcutaneously injected into mice. The in vitro release studies indicated that HK could be released from HK‐PCEC and HK‐PCEC‐PECE in a sustained manner. Such biodegradable smart drug‐delivery system might have great potential application in injectable hydrophobic drug local delivery system. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2010
Fourier transform convolution integrals applied to generalized Born molecular volume
Authors: Schüpbach Thierry , Zoete Vincent , Tsakam‐Sotché Brice , Michielin Olivier
Published: June 2009

Generalized Born methods are currently among the solvation models most commonly used for biological applications. We reformulate the generalized Born molecular volume method initially described by (Lee et al, 2003, J Phys Chem, 116, 10606; Lee et al, 2003, J Comp Chem, 24, 1348) using fast Fourier transform convolution integrals. Changes in the initial method are discussed and analyzed. Finally, the method is extensively checked with snapshots from common molecular modeling applications: binding free energy computations and docking. Biologically relevant test systems are chosen, including 855–36091 atoms. It is clearly demonstrated that, precision‐wise, the proposed method performs as good as the original, and could better benefit from hardware accelerated boards. © 2009 Wiley Periodicals, Inc. J Comput Chem, 2010
Predicting the tautomeric equilibrium of acetylacetone in solution. I. The right answer for the wrong reason?
Authors: Schlund Sebastian , Basílio Janke Eline M. , Weisz Klaus , Engels Bernd
Published: June 2009

This study investigates how the various components (method, basis set, and treatment of solvent effects) of a theoretical approach influence the relative energies between keto and enol forms of acetylacetone, which is an important model system to study the solvent effects on chemical equilibria from experiment and theory. The computations show that the most popular density functional theory (DFT) approaches, such as B3LYP overestimate the stability of the enol form with respect to the keto form by ∼10 kJ mol−1, whereas the very promising SCS‐MP2 approach is underestimating it. MP2 calculations indicate that in particular the basis set size is crucial. The Dunning Huzinaga double ζ basis (D95z(d,p)) used in previous studies overestimates the stability of the keto form considerably as does the popular split‐valence plus polarization (SVP) basis. Bulk properties of the solvent included by continuum approaches strongly stabilize the keto form, but they are not sufficient to reproduce the reversal in stabilities measured by low‐temperature nuclear magnetic resonance experiments in freonic solvents. Enthalpic and entropic effects further stabilize the keto form, however, the reversal is only obtained if also molecular effects are taken into account. Such molecular effects seem to influence only the energy difference between the keto and the enol forms. Trends arising due to variation in the dielectric constant of the solvent result from bulk properties of the solvent, i.e., are already nicely described by continuum approaches. As such this study delivers a deep insight into the abilities of various approaches to describe solvent effects on chemical equilibria. © 2009 Wiley Periodicals, Inc. J Comput Chem, 2010
Influence of differently ionized species on fragmentation pathways and energetics of a potential adenosine receptor antagonist using a triple quadrupole and a multistage LTQ‐Orbitrap™ FTMS instrument
Authors: Zhong Wendy , Irish Patrick A. , Martin Gary E.
Published: June 2009

magnified image

A systematic study was conducted to investigate the influence of differently ionized species on the fragmentation pathways and energetics of a piperazine‐containing adenosine by using different cations or anions. Very different fragmentation mechanisms were observed in protonated‐ versus sodiated‐molecules, which indicated that the proton is mobilized to promote the charge‐direct fragmentation, whereas Na+ cation was fixed at the heterotricyclic ring structure provoking charge‐remote fragment ions. This finding was also supported by the results observed in the fragmentation behaviors in the deprotonated‐molecule. The energetics of these fragment ions were also explored by using the breakdown curves obtained from the triple quadrupole and LTQ‐Orbitrap™ instrument. The data indicated that the lowest energy pathways in the protonated‐molecule [M+H]+ involve breaking a CN bond connecting an ethylene bridge and heterotricyclic ring structure. The lowest energy pathway is the cleavage of a CO bond connecting the methoxy ethyl group and phenolic oxygen to form a distonic radical ion for a sodiated‐molecule [M+Na+]and a deprotonated‐molecule [M‐H]−. The data suggest that by choosing the differently ionized species, one can probe different fragmentation channels that can provide additional structure information for an unknown impurity and possibly degradation product identification. In addition, by comparing the data obtained from triple quadrupole and LTQ‐Orbitrap instruments, one can develop further understanding of the differences in the fragmentation behaviors due to the variations in the collision activation‐dissociation process. From the side‐by‐side comparison with the breakdown curves obtained for both instruments, the difference in fragmentation behaviors caused by the difference in dissociation processes that occur in these two types of instruments can be probed. J. Heterocyclic Chem., (2009).
Persistent decline in longitudinal and radial strain after coronary microembolization detected on velocity encoded phase contrast magnetic resonance imaging
Authors: Dicks Demetrius L. , Carlsson Marcus , Heiberg Einar , Martin Alastair , Saloner David , Arheden Hakan , Saeed Maythem
Published: June 2009

Purpose

To use velocity‐encoded phase contrast (PC) MRI in assessing the effect of coronary microembolization on longitudinal and radial myocardial strain.

Materials and Methods

A combined X‐ray and MR system (XMR) was used for selective left anterior descending artery catheterization and microinfarct assessment in swine (n = 6). The embolized area at risk was defined on perfusion MRI followed by administration of a 7500 count (size = 100–300 μm) of the embolic agent. Quantification of strain and microinfarction was performed at 1 h and 1 week using PC‐MRI and delayed enhancement (DE) MRI, respectively. At postmortem, sliced hearts were stained to define microinfarction.

Results

Baseline longitudinal and radial strain did not differ between area‐at‐risk and remote myocardium. The embolized territory (area at risk) showed significant decline in longitudinal strain from −11.5 ± 3.2% to 1.8 ± 2.5% at 1 h (P < 0.05) and −3.9 ± 1.1% at 1 week (P < 0.05). Similarly, regional radial strain progressively declined from 23.6 ± 2.5% at baseline to 12.5 ± 3.7% at 1 h (P < 0.05) and 4.8 ± 5.0% at 1 week (P < 0.01). The size of microinfarction was not significantly different between DE‐MRI and histochemical staining.

Conclusion

PC‐MRI is sensitive in assessing changes in regional longitudinal and radial strain after coronary embolization. Longitudinal and radial strain of the hyperenhanced patchy microinfarction demonstrates persistent decline over the course of 1 week. J. Magn. Reson. Imaging 2009;30:69–76. © 2009 Wiley‐Liss, Inc.
Automated estimation of regional mean transition times and radial velocities from cine magnetic resonance images: Evaluation in normal subjects
Authors: El‐Berbari Racha , Kachenoura Nadjia , Redheuil Alban , Giron Alain , Mousseaux Elie , Herment Alain , Bloch Isabelle , Frouin Frédérique
Published: June 2009

Purpose

To assess regional ventricular function via an accurate and automated definition of functional parameters.

Materials and Methods

An automated method is proposed that estimates reliable regional normalized mean transition times (Fmc) and mean radial velocities (Vm) from cine images. This approach combines a quantitative parametric imaging method and an automated detection of the endocardial border, which is robust to the presence of papillary muscles and nonhomogeneities within the left ventricular cavity. Steady‐state free‐precession cine‐magnetic resonance imaging (MRI) of 36 healthy subjects was analyzed.

Results

The quality of the automated segmentation was assessed on a subgroup of 20 subjects by comparing the results with the manual contours traced by an expert. The comparison of functional parameters estimated consequently using the automated and the manual contours yielded (y = 0.959x + 0.016, R = 0.964) for Fmc and (y = 0.883x + 0.505, R = 0.935) for Vm. On the entire group, Fmc was equal to 0.392 ± 0.069 and Vm to 5.4 ± 2.3 cm/s. Increasing values of the temporal parameter from the apex to the base and larger values in the septal wall than in lateral wall were demonstrated and were in accordance with the physiology.

Conclusion

The proposed method ensures an automated and robust assessment of regional wall motion parameters, which could be clinically useful. J. Magn. Reson. Imaging 2009;30:236–242. © 2009 Wiley‐Liss, Inc.
SAR and power implications of different RF shimming strategies in the pelvis for 7T MRI
Authors: van den Bergen Bob , van den Berg Cornelis A.T. , Klomp Dennis W.J. , Lagendijk Jan J.W.
Published: June 2009

Purpose

To determine the best radiofrequency (RF) shimming method for 7 T body imaging that provides sufficient B1+ excitation inside the target region while energy deposition (SAR) and power demands are as low as possible and that does not incorporate anatomy specific electric field information inside the patient models, as this information is not available in practice.

Materials and Methods

Finite difference time domain (FDTD) simulations were used to evaluate five RF shimming strategies for the pelvis inside a body coil. The results were compared to the theoretical best solution that could be achieved if the electric field inside the patient was known.

Results

Most of the RF shimming strategies were successful. However, between the different strategies a factor of two difference in average SAR reduction, a factor of three difference in local maximum SAR reduction, and a factor of 20 difference in power efficiency was observed. Phase matching was found to be the most promising RF shimming method for the body coil used and patient models.

Conclusion

RF shimming can reduce the SAR and improve power efficiency in an accurate patient model without knowing the electric field. However, choosing the right method is critical to prevent unexpected behavior in local SAR deposition. J. Magn. Reson. Imaging 2009;30:194–202. © 2009 Wiley‐Liss, Inc.
Characterization of low‐grade gliomas using RGB color maps derived from ADC histograms
Authors: Khayal Inas S. , Nelson Sarah J.
Published: June 2009

Purpose

To use normalized apparent diffusion coefficient (nADC) histograms from patients with grade II oligodendroglioma (OD) and astrocytoma (AC) to generate RGB color maps that emphasize the differences between normal‐appearing white matter (NAWM), oligo‐like, and astro‐like regions.

Materials and Methods

NAWM and nonenhancing lesion (NEL) ADC values from 19 ODs and 11 ACs were summed to generate oligo‐like (red), NAWM (green), and astro‐like (blue) nADC histograms. These nADC histograms were then used to map nADC values to an RGB matrix.

Results

Color maps of oligodendroglial tumor regions were generally visualized in pink, while color maps of astrocytic tumor regions showed various shades of blue. This technique was also applied to 23 patients with the more mixed subtype, oligoastrocytoma (OA), which showed a mixture of both blue and pink, which in many cases appeared to bleed into each other and were blotchy.

Conclusion

This technique allows for the visualization of biologically different regions within the whole tumor mass, which may aid in directing image‐guided biopsies. This can be used to ensure that the biopsy is directed to regions that can more accurately define the dominant tumor characteristics. J. Magn. Reson. Imaging 2009;30:209–213. © 2009 Wiley‐Liss, Inc.