bluuebunny/crossref_metadata_2025 huggingface dataset:
ChemInform Abstract: High‐Relaxivity MRI Contrast Agents: Where Coordination Chemistry Meets Medical Imaging
Authors: Werner Eric J. , Datta Ankona , Jocher Christoph J. , Raymond Kenneth N.
Published: December 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Steroidal Saponins
Authors: Sahu N. P. , Banerjee S. , Mondal N. B. , Mandal D.
Published: December 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Specific Targeting of Metzincin Family Members with Small‐Molecule Inhibitors: Progress Toward a Multifarious Challenge
Authors: Georgiadis Dimitris , Yiotakis Athanasios
Published: December 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Peptidomimetic Therapeutic Agents Targeting the Protease Enzyme of the Human Immunodeficiency Virus and Hepatitis C Virus
Authors: Tsantrizos Youla S.
Published: December 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Design of Small‐Molecule Peptidic and Nonpeptidic Smac Mimetics
Authors: Sun Haiying , Nikolovska‐Coleska Zaneta , Yang Chao‐Yie , Qian Dongguang , Lu Jianfeng , Qiu Su , Bai Longchuan , Peng Yuefeng , Cai Qian , Wang Shaomeng
Published: December 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Syntheses of the Tedanolides
Authors: Roy Myriam , Kalesse Markus
Published: December 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Open Problems in Chemical Topology
Authors: Fenlon Edward E.
Published: December 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Theoretical Studies on Thermolysis Mechanism and Stability of trans‐1,4,5,8‐Tetranitro‐1,4,5,8‐tetraazadecalin Isomers
Authors: QIU Ling , GONG Xue‐Dong , XIAO He‐Ming
Published: December 2008

A systematic study on the thermolysis mechanism and stability of a series of energetic cyclic nitramines, trans‐1,4,5,8‐tetranitro‐1,4,5,8‐tetraazadecalin isomers, was performed by density functional theory (DFT) and semiempirical molecular orbital (MO) calculations. Bond dissociation energies (BDE) and activation energies (Ea) of the thermolysis processes were computed at the B3LYP/6‐31G∗︁∗︁ and PM3 levels, respectively. The effect of nitroamino groups on the thermal stability and pyrolysis mechanism of the title compounds was evaluated by the BDE and Ea. The correlations among BDE, Ea, bond overlap populations, energies of the frontier orbitals, and energy gaps were examined in detail. The results indicate that thermal stabilities and decomposition mechanisms of the title compounds derived from the BDE, Ea and static electronic parameters are basically consistent. Homolysis of the N–NO2 bond is the initial step in the thermolysis of the title compounds, the meta‐isomers are more stable than the para‐isomers, and the ortho‐isomers are the most sensitive.
Hydrothermal Synthesis and Structural Characterization of Two Zinc Coordination Polymers of 1,2‐Di(4‐pyridyl)ethylene and Benzenedicarboxylate
Authors: LIU , Dong , LI Hong‐Xi , CHEN Yang , ZHANG Yong , LANG Jian‐Ping
Published: December 2008

Hydrothermal reactions of Zn(NO3)2·6H2O with 1,2‐di(4‐pyridyl)ethylene (dpe) and 1,4‐benzenedicarboxylate (1,4‐BDC) or 1,3‐benzenedicarboxylate (1,3‐BDC) in water gave rise to two new metal‐organic coordination polymers, [Zn(1,4‐BDC)(dpe)]n (1) and [Zn4O(1,3‐BDC)3(dpe)]n (2). Both compounds were characterized by elemental analysis and IR spectroscopy, and their structures were determined by single crystal X‐ray diffraction. 1 displays a rare 5‐fold interpenetrating 66‐diamondoid framework while 2 possesses an interlocked 3D network formed by inclined interpenetration of 2D (4,4) networks that are constructed by µ4‐oxo tetrazinc Zn4O cores and the bridging dpe and 1,3‐BDC ligands. Thermal and photoluminescent properties of 1 and 2 were also investigated.
Study on the Interaction of Ketoconazole with Human and Bovine Serum Albumins by Fluorescence Spectroscopy
Authors: GUO Qing‐Lian , LI Ran , ZHOU Xin , LIU Yi
Published: December 2008

The binding of ketoconazole to human serum albumin and bovine serum albumin was studied by using fluorescence and ultraviolet spectroscopy. The measurements were performed in 0.1 mol·L−1phosphate buffer solution at pH=7.40±0.1. Decreasing of quenching constant was observed in association with temperature increase. Our findings show that the quenching mechanism of fluorescence of serum albumins by ketoconazole was static quenching because of compound formation. The thermodynamic parametersΔG,ΔH, andΔSat different temperatures were calculated, showing that the electrostatic interactions and hydrophobic interaction are the main forces for the binding of ketoconazole to serum albumins. The distancerbetween the donor (Trp‐214) and acceptor (ketoconazole) was obtained according to fluorescence resonance energy transfer theory.
DFT Study on the Effect of Different Peripheral Chains on Charge Transport Properties of Triphenylene Derivatives
Authors: CHEN Jun‐Rong , CAI Jing , XU Bu‐Yi , LI Quan , ZHAO Ke‐Qing
Published: December 2008

Based on the semi‐classical model of the charge transport, theoretical studies on the effect of different peripheral chains including alkynyl on charge transport properties of triphenylene have been carried out using density functional theory (DFT) at the level of B3LYP/6‐31G∗︁∗︁. The results indicate that all the title compounds are advantageous to the charge transport. The introduction of amide RCONH to the discotic ring of triphenylene can raise the positive charge transport rate largely, and introduction of ester in peripheral chains is helpful to the positive charge transport and negative charge transport. The positive charge transport properties of monosubstituted triphenylene are better than those of disubstituted and trisubstituted triphenylenes obviously.
A Rapid and Highly Selective Resonance Scattering Spectral Assay for Trace Carcinoembryonic Antigen
Authors: LI Jian‐Fu , JIANG Zhi‐Liang , DENG An‐Ping
Published: December 2008

Gold nanoparticles, in size of 10 nm, were used to label monoclonal carcinoembryonic antigen antibody (CEAAb) to obtain an immunonanogold resonance scattering (RS) spectral probe (AuCEAAb) for the measurement of trace carcinoembryonic antigen (CEA). In pH 6.8 Na2HPO4‐NaH2PO4 buffer solution and the presence of polyethylene glycol (PEG)‐6000, the AuCEAAb combined with CEA to form the nanogold‐labeled immunocomplex clusters in average size of 227 nm, which exhibited two scattering peaks at about 320 and 581 nm. The enhanced RS intensity at 581 nm (ΔI581 nm) is proportional to CEA concentration in the range of 1.0–50.0 ng/mL, with a detection limit (DL) of 0.52 ng/mL. The immunonanogold RS assay was utilized to determine CEA in serum samples with high sensitivity, good selectivity and simplicity.
Functional implications of membrane modification with semenogelins for inhibition of sperm motility in humans
Authors: Yoshida Kaoru , Krasznai Zoárd Tibor , Krasznai Zoltán , Yoshiike Miki , Kawano Natsuko , Yoshida Manabu , Morisawa Masaaki , Tóth Zoltán , Bazsáné Zsuzsa Kassai , Márián Teréz , Iwamoto Teruaki
Published: December 2008

Semenogelin I and II (Sgs) are the major component of human semen coagulum. The protein is rapidly cleaved after ejaculation by a prostate‐specific antigen, resulting in liquefaction of the semen coagulum and the progressive release of motile spermatozoa. Sgs inhibit human sperm motility; however, there is currently no information on its effect on the sperm membrane. This study investigated the role of Sgs on human sperm motility through regulation of membrane potential and membrane permeability. Fresh semen samples were obtained from normozoospermic volunteers, and studies were conducted using motile cells selected using the swim‐up method. Sgs changed the characteristics of sperm motion from circular to straightforward as evaluated by a computer‐assisted motility analyzer, and all parameters were decreased more than 2.5 mg/mL. The results demonstrate that Sgs treatment immediately hyperpolarized the membrane potential of swim‐up‐selected sperm, changed the membrane structure, and time‐dependently increased membrane permeability, as determined through flow cytometric analysis. The biphasic effects of Sgs were time‐ and dose‐dependent and partially reversible. In addition, a monoclonal antibody against Sgs showed positive binding to cell membrane proteins in fixed cells, observed with confocal fluorescence microscopy. These results demonstrate that Sgs modifies the membrane structure, indirectly inhibiting motility, and provides suggestions for a therapy for male infertility through selection of a functional sperm population using Sgs. Cell Motil. Cytoskeleton 2009. © 2008 Wiley‐Liss, Inc.
Pyridylalanine‐Containing Hydroxamic Acids as Selective HDAC6 Inhibitors
Authors: Schäfer Stefan , Saunders Laura , Schlimme Sonja , Valkov Vassil , Wagner Julia M. , Kratz Felix , Sippl Wolfgang , Verdin Eric , Jung Manfred
Published: December 2008

Pyridylalanine inhibitors of histone deacetylase (HDAC) have been synthesized that show selectivity for the isoform HDAC6 over HDAC1 in vitro. This selectivity was also identified in cancer cells by analyzing tubulin versus histone acetylation. The compounds show decreased intrinsic cytotoxicity relative to pan‐HDAC inhibitors, but show antiproliferative synergy with the proteasome inhibitor bortezomib.

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We synthesized hydroxamic acids with a pyridylalanine substructure and identified them as selective inhibitors of human recombinant HDAC6. The in vitro selectivity was up to 25‐fold for HDAC6 over HDAC1 and was confirmed by Western blotting to assess tubulin versus histone acetylation in cancer cells. Docking studies with an HDAC6 homology model suggested that the hydrophobic cap group of the inhibitors interacts with aromatic residues that form a sub‐pocket near the entrance of the substrate binding channel. The HDAC6‐selective compounds have less cytotoxicity toward cancer cells than do pan‐HDAC inhibitors. The synergistic antiproliferative activity we showed with the proteasome inhibitor bortezomib suggests the potential for combination anticancer therapy with less general toxicity.
Phase 2 trial of carboplatin, weekly paclitaxel, and biweekly bevacizumab in patients with unresectable stage IV melanoma
Authors: Perez Domingo G. , Suman Vera J. , Fitch Tom R. , Amatruda Thomas , Morton Roscoe F. , Jilani Shamim Z. , Constantinou Costas L. , Egner James R. , Kottschade Lisa A. , Markovic Svetomir N.
Published: December 2008

BACKGROUND: Vascular endothelial growth factor (VEGF) plays an important role in the growth and metastatic progression of melanoma. Exposure of melanoma cells to chemotherapy induces VEGF overproduction, which in turn may allow melanoma cells to evade cell death and become chemotherapy resistant. Therefore, in patients with metastatic melanoma, the combination of chemotherapy with an agent that specifically targets VEGF might be able to control tumor growth and progression more effectively than chemotherapy alone. METHODS: A 2‐stage phase 2 clinical trial was conducted in patients with unresectable stage IV (metastatic) melanoma to assess antitumor activity and the toxicity profile of the combination of carboplatin (area under the curve 6 iv on Day 1 of a 28‐day cycle), paclitaxel (80 mg/m2 iv on Days 1, 8, and 15), and bevacizumab (10 mg/kg iv on Days 1 and 15). Treatment was continued until progression or intolerable toxicity. RESULTS: Fifty‐three patients (62.3% male) were enrolled. Nine (17%) patients achieved partial remission, and another 30 (57%) achieved stable disease for at least 8 weeks. Median progression‐free survival and median overall survival were 6 months and 12 months, respectively. One patient died after 8 treatment cycles from intracranial hemorrhage into undiagnosed brain metastases. The most common severe (grade ≥3) toxicities were neutropenia (53%), thrombocytopenia (11%), hypertension (9%), and anemia (8%). CONCLUSIONS: This combination of carboplatin, paclitaxel, and bevacizumab appears to be moderately well tolerated and clinically beneficial in patients with metastatic melanoma. Further study of this combination is warranted. Cancer 2009. © 2008 American Cancer Society.
Critical and diverse involvement of Akt/mammalian target of rapamycin signaling in human lung carcinomas
Authors: Dobashi Yoh , Suzuki Shioto , Matsubara Hirochika , Kimura Maiko , Endo Shunsuke , Ooi Akishi
Published: December 2008

BACKGROUND: Aberrant signaling cascades emanating from epidermal growth factor receptor (EGFR) are involved in the complex network of oncogenic signaling in lung carcinomas. One representative cascade is the phosphatidylinositol 3‐kinase/Akt/mammalian target of rapamycin (mTOR) pathway. METHODS: The authors investigated the involvement of mTOR in the pathobiologic profiles of 150 specimens of lung carcinoma by immunohistochemistry and immunoblotting in correlation with the upstream and downstream proteins Akt and p70S6‐kinase (S6K), respectively. RESULTS: Immunohistochemistry revealed Akt activation in 44% of tumors and mTOR expression in 68.7% of tumors, and the preponderance of activation was observed in adenocarcinoma (AC) (100%). Phosphorylated mTOR (p‐mTOR) was observed in 53.3% of tumors and had the highest frequency in AC (89.7%). In AC, the frequency of p‐mTOR staining was higher in the well differentiated subtype, in particular, in the acinar structure. However, little correlation was observed between the activation of mTOR and Akt, except in the 5 AC specimens that harbored an EGFR gene mutation, which exhibited constitutive activation of both Akt and mTOR. Conversely, in squamous cell carcinomas, mTOR activation was associated with a significantly higher frequency of lymph node metastasis. CONCLUSIONS: The results of this study suggested the dual functions of mTOR. First, mTOR may function not only in the proliferation of tumor cells as an effector molecule downstream of EGFR but also possibly in the morphogenesis of AC. Second, the activation of mTOR may play a key role in metastasis in squamous cell carcinoma. Overall, the current results demonstrated the potential for the application of rapamycin, an mTOR inhibitor, as an additional novel component of chemotherapy for a defined subset of patients with lung carcinoma. Cancer 2009. © 2008 American Cancer Society.
Sex and race in bladder cancer: What we have learned and future directions
Authors: Katz Mark H. , Steinberg Gary D.
Published: December 2008

After controlling for prognostic variables, women and African Americans present with more advanced bladder cancer and have worse cancer‐specific survival than other patient populations. Clinicians must focus on social factors influencing this disparity and on increasing public awareness and education to help standardize the diagnosis and management of bladder cancer for all patients.
Palladium(II) Phosphotungstate Derivatives: Synthesis and Characterization of the [Pdx{WO(H2O)}3–x{A,α‐PW9O34}2](6+2x)– Anions
Authors: Villanneau Richard , Renaudineau Séverine , Herson Patrick , Boubekeur Kamal , Thouvenot René , Proust Anna
Published: December 2008

A series of PdII derivatives of the [P2W21O71(H2O)3]6– heteropolytungstate with the general formula [Pdx{WO(H2O)}3–x{A,α‐PW9O34}2](6+2x)– (x = 1–3) is described. These compounds are obtained by the reaction between [PdII(NO3)2]·H2O and the corresponding vacant polyoxometalates in water. They are characterized by IR and multinuclear NMR (31P and 183W) spectroscopy. Compound K10[Pd2{WO(H2O)}{A,α‐PW9O34}2]·30H2O was characterized by XRD: it crystallized in the orthorhombic space group Pcmn with parameters a = 18.119(3) Å, b = 19.729(3) Å, c = 24.856(5) Å, V = 8886(3) Å3.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Superparamagnetic Composites: Magnetism with No Memory
Authors: Tartaj Pedro
Published: December 2008

The past five years have witnessed a renewed interest in the field of superparamagnetic composites driven by both the excitement of understanding individual and cooperative properties at the nanoscale and the potential for the use of such composites in catalysis, magneto‐optics, and specially bioscience, where new applications are emerging. The basis for the interest in superparamagnetic composites lies in the combination of superparamagnetic nanoparticles with matrixes of different nature. Superparamagnetic nanoparticles endow the composites with adequate magnetic functionality (guiding, monitoring, heating), while the matrixes improve stability (sedimentation, shielding), chemical functionality, and compatibility (hydrophobicity or hydrophilicity, toxicity,stealth). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Louis Fieser: An Organic Chemist in Peace and War
Authors: Lenoir Dieter , Tidwell Thomas T.
Published: December 2008

Louis Frederick Fieser (1899–1977) was an prominent figure among organic chemists of the mid‐20thcentury, identified today forReagents for Organic Synthesis, co‐authored with his wife Mary Fieser, and now available electronically. Fieser was first known for his prolific research efforts in quinones, polycyclic aromatics, and steroids, and was also a leading educator and public servant. His activities included not only major achievements in cancer research and cancer prevention through the suppression of smoking, but also participation in war research and the invention of napalm, which are part of his legacy.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Screening the Structural Space of Bicyclo‐DNA: Synthesis and Thermal Melting Properties of bc4,3‐DNA
Authors: Stauffiger Andrea , Leumann Christian J.
Published: December 2008

In attempts to screen the structural and functional properties of bicyclo‐DNA, in which the ribose C(3′) and C(5′) centers are integrated into an additional five‐membered carbocyclic ring ([3.3.0]‐series) we have now synthesized and investigated a ring enlarged analogue in which C(5′) and C(3′) are spanned by a six‐membered carbocyclic ring ([4.3.0]‐series). The synthesis of the corresponding bc4,3‐T nucleoside 13 was performed in 12 steps by starting from known allyl furanose 1. X‐ray analysis of its benzyl protected precursor 12 showed the cyclohexane ring to adopt a chair conformation with the O(5′) substituent in an axial position. The furanose part shows clearly S‐type sugar pucker. This nucleoside was converted into the corresponding phosphoramidite building block 15 and incorporated into oligodeoxynucleotides by standard phosphoramidite chemistry. The thermal stabilities of oligonucleotides with single or double incorporations of bc4,3‐T residues, paired to complementary DNA or RNA, were found to be similar to those of unmodified oligonucleotides (–2.3 to +0.7 °C per modification) and to those with the known bc‐T modifications. We also found that mismatch discrimination in the bc4,3‐T series was similar to that of the natural series but less discriminative in comparison to the known bc‐T series.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Chlorophyll Catabolites – Chemical and Structural Footprints of a Fascinating Biological Phenomenon (Eur. J. Org. Chem. 1/2009)
Authors: Moser Simone , Müller Thomas , Oberhuber Michael , Kräutler Bernhard
Published: December 2008

The cover picture shows a ripe apple and a yellow leaf from an apple tree. In ripening fruit and in leaf senescence, the green plant pigment chlorophyll is degraded to tetrapyrrolic, colourless catabolites (so‐called NCCs), such as the one described by the structural formula given. The present knowledge on the occurrence and structural properties of chlorophyll catabolites in higher plants is outlined in the Microreview by B. Kräutler et al. on p. 21 f. Picture courtesy of Dr. Thomas Müller, University of Innsbruck, Austria.
Microwave‐Assisted Electroanalysis: A Review
Authors: Cutress Ian J. , Marken Frank , Compton Richard G.
Published: December 2008

Microwave‐assisted electrochemistry is critically discussed with a focus on the fundamental aspects of the processes involved and its applications in electroanalysis. The concept of direct and nondirect heated electrodes is discussed, and simulation work is evaluated. Microwave‐assisted electrochemistry predominantly results in higher current responses (up to 2 magnitudes higher) due to increased temperature and mass transport to the active electrodes. Temperature gradients at microwave‐affected electrodes may exceed 105 K/cm, with temperature hotspots found in the thin diffusion layers set up at ultramicroelectrodes. Research into microwave‐assisted electroanalysis can lead to enhanced capillary electrophoresis detection, improved stripping voltammetry and development of new high temperature methods.
New taxa of Allium L. subg. Allium (Alliaceae) from Tajikistan and Uzbekistan
Authors: Fritsch R. M. , Khassanov F. O.
Published: December 2008

The alliances of Allium filidens Regel and A. brevidens Vved. were taxonomically revised. Three subspecies were recognized for A. filidens. The widely distributed typical subspecies is characterized by thick reticulate bulb tunics, relatively short leaf sheathes, and whitish tepals with greenish or bluish median veins. Subspecies ugamicum (Vved.) R.M.Fritsch & F.O.Khass. occurring in Chatkal, Pskem, and Ugam mountain ranges E and NE of Tashkent, has delicate, reticulate bulb tunics, relatively longer leaf sheathes, and faintly blue to violet flowers. Subspecies mogianense R.M.Fritsch & F.O.Khass. occupies a small area of distribution in western Hissar mountain range and differs from subsp. ugamicum by greenish tepals with broad green median veins. A key for determination of these subspecies is given. Allium brevidens subsp. pshikharvium R.M.Fritsch & F.O.Khass. was newly described from higher altitudes of Tajik Vanch, Darvaz, and Peter I. mountain ranges. It differs from the typical subspecies by larger scapes, denser inflorescences, green (not yellowish) tepals with dark‐green median veins and violet (not purplish) filaments. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Numerical simulation of tangentially injected turbulent swirling flow in a divergent tube
Authors: Guo Hui‐Fen , Chen Zhi‐Yong
Published: December 2008

This paper studies the properties of turbulent swirling decaying flow induced by tangential inlets in a divergent pipe using the realizable k–ε turbulence model and discusses the effects of the injector pressure and injection position. The results of transient solutions show that both the recirculation zone near the wall in upstream of the injectors and the vortex breakdown in downstream of the injectors increase in size during the whole period. A nearly axisymmetric conical breakdown is formed and its internal structure consists of two asymmetric spiral‐like vortices rotating in opposite directions. The stagnation point shifts slowly toward the pipe outlet over time. The maxima of the three velocity components, which are located near the wall, decrease gradually with streamwise direction. It can also be inferred that Mach number approaches 1.0 near the injector outlets. The velocities increase with the increasing injector pressure. However, its increasing trend is not significant. With the increase of the injection position, vortex breakdown moves in downstream direction and the pitch along the streamwise direction increases. Copyright © 2008 John Wiley & Sons, Ltd.
Improving outcomes for workers with mental retardation
Authors: Fornes Sandra , Rocco Tonette S. , Rosenberg Howard
Published: December 2008

This research presents an analysis of factors predicting job retention, job satisfaction, and job performance of workers with mental retardation. The findings highlight self‐determination as a critical skill in predicting the three important employee outcomes. The study examined a hypothesized job retention model and the outcome of the three regression analyses used to test the model. The intent of the study was to develop job retention strategies that could offer rehabilitation and HR professionals a useful structure for understanding and implementing job retention interventions for people with mental retardation.
Stability of cognitive impairment in chronic schizophrenia over brief and intermediate re‐test intervals
Authors: Pietrzak Robert H. , Snyder Peter J. , Jackson Colleen E. , Olver James , Norman Trevor , Piskulic Danijela , Maruff Paul
Published: December 2008

Objective

This study examined between‐ and within‐subject stability of cognitive performance in individuals with chronic schizophrenia.

Methods

Thirty individuals with schizophrenia and 20 healthy controls matched by age, sex, education, and estimated IQ underwent repeated cognitive assessments at baseline and 30 days using computerized tests of psychomotor function, visual attention/information processing, non‐verbal learning, and executive function.

Results

Compared to healthy controls, individuals with schizophrenia scored lower on all cognitive measures and demonstrated greater variability in cognitive performance. Within‐subject variability in cognitive performance in both the schizophrenia and healthy control groups remained stable at brief (i.e., hours) and intermediate (i.e., one month) assessments.

Conclusions

These results demonstrate the stability of between‐ and within‐subject variability in cognitive performance in schizophrenia, and suggest that variability in cognitive performance may reflect an inherent characteristic of the disorder, rather than differences in test–retest reliability/error of cognitive measures. Copyright © 2008 John Wiley & Sons, Ltd.
Changes in thaw lake drainage in the Western Canadian Arctic from 1950 to 2000
Authors: Marsh Philip , Russell Mark , Pohl Stefan , Haywood Heather , Onclin Cuyler
Published: December 2008

The permafrost of the Western Canadian Arctic has a very high ground ice content. As a result, the vast number of thaw lakes in this area are very sensitive to a changing climate. With thaw lakes prone to either increases in area due to thermokarst processes, or complete drainage in less than one day due to melting of channels through ice‐rich permafrost. After a lake drains, it leaves a topographic basin that is often termed a Drained Thaw Lake Basin (DTLB). An analysis of aerial photographs and topographic maps showed that 41 lakes drained in the study area between 1950 and 2000, for a rate of slightly less than one lake per year. The rate of drainage over three time periods (1950–1973, 1973–1985, 1985–2000), decreased from over 1 lake/year to approximately 0·3 lake/year. The reason for this decrease is not known, but it is hypothesized that it is related to the effect of a warming climate. There is a large spatial variation in DTLBs, with higher number of drained lakes in physiographic areas with poor drainage. It is likely that this variation is related to variations in ground ice. Although previous studies have suggested that lakes drain during periods of high water level, it is likely that a combination of a warm summer, a resulting deep active layer, and a moderately high lake level were responsible for the drainage of a lake in the study area during the summer of 1989. Although this study has documented changes in the rate of lake drainage over a 50‐year period, there is a need for further research to better understand the complex interactions between climate, geomorphology, and hydrology responsible for this change, and to further consider the potential hazard rapid lake drainage poses to future industrial or resource development in the area. Copyright © 2008 John Wiley & Sons, Ltd and Her Majesty the Queen in right of Canada. The contributions of P. Marsh, M. Russell, H. Haywood and C. Onclin belong to the Crown in right of Canada and are reproduced with the permission of Environment Canada.
Impacts of permafrost degradation on arctic river biogeochemistry
Authors: Frey Karen E. , McClelland James W.
Published: December 2008

Over the next century, near‐surface permafrost across the circumpolar Arctic is expected to degrade significantly, particularly for land areas south of 70°N. This is likely to cause widespread impacts on arctic hydrology, ecology, and trace gas emissions. Here, we present a review of recent studies investigating linkages between permafrost dynamics and river biogeochemistry in the Arctic, including consideration of likely impacts that warming‐induced changes in permafrost may be having (or will have in the future) on the delivery of organic matter, inorganic nutrients, and major ions to the Arctic Ocean. These interacting processes can be highly complex and undoubtedly exhibit spatial and temporal variabilities associated with current permafrost conditions, sensitivity to permafrost thaw, mode of permafrost degradation (overall permafrost thaw, active layer deepening, and/or thermokarst processes), and environmental characteristics of watersheds (e.g. land cover, soil type, and topography). One of the most profound consequences of permafrost thaw projected for the future is that the arctic terrestrial freshwater system is likely to experience a transition from a surface water‐dominated system to a groundwater‐dominated system. Along with many other cascading impacts from this transition, mineral‐rich groundwater may become an important contributor to streamflow, in addition to the currently dominant contribution from mineral‐poor surface water. Most studies observe or predict an increase in major ion, phosphate, and silicate export with this shift towards greater groundwater contributions. However, we see conflicting accounts of whether the delivery of inorganic nitrogen and organic matter will increase or decrease with warming and permafrost thaw. It is important to note that uncertainties in the predictions of the total flux of biogeochemical constituents are tightly linked to future uncertainties in discharge of rivers. Nonetheless, it is clear that over the next century there will be important shifts in the river transport of organic matter, inorganic nutrients, and major ions, which may in turn have critical implications for primary production and carbon cycling on arctic shelves and in the Arctic Ocean basin interior. Copyright © 2008 John Wiley & Sons, Ltd.
The impact of a shrinking cryosphere on the form of arctic alluvial channels
Authors: McNamara James P. , Kane Douglas L.
Published: December 2008

A shrinking cryosphere has important implications for the geomorphology of alluvial channels in arctic catchments because ice and permafrost alter the driving and resisting forces responsible for shaping local channel cross sections. For example, bedfast ice in shallow channels can suppress bedload transport during snowmelt events causing a reduction in the frequency of geomorphically effective flows, while cap ice in deeper channels can alter stream hydraulics. The impact of these local controls on catchment‐scale geomorphic patterns, however, is less certain. A case study of one arctic river in northern Alaska, USA, reveals hydraulic geometry anomalies that can be reasonably explained by the influence of ice and permafrost on local channel form. However, there is a critical lack of data from rivers wholly contained in the continuous permafrost zone preventing comprehensive understanding of how arctic rivers might respond in a shrinking cryosphere. Copyright © 2008 John Wiley & Sons, Ltd.
Elution kinetics, antimicrobial efficacy, and degradation and microvasculature of a new gentamicin‐loaded collagen fleece
Authors: Kilian Olaf , Hossain Hamid , Flesch Ingo , Sommer Ursula , Nolting Heiko , Chakraborty Trinad , Schnettler Reinhard
Published: December 2008

Management of bone and soft tissue infections generally includes surgical procedures as well as attendant treatment and prevention with gentamicin‐loaded fleeces. Conventional gentamicin‐containing collagen fleeces currently in use are strongly acidic and exhibit limited biocompatibility thereby adversely affecting wound healing. To improve the antibiotic delivery system, a new phosphate‐buffered, gentamicin‐loaded fleece with pH–neutral properties has been developed (Jason G®). This study aimed at comparing the elution kinetics of gentamicin release and the antimicrobial efficacy of conventional fleeces with the newly developed fleece in vitro. In addition, degradation and microvasculature of implanted fleeces were examined in a rat model and assessed using histology, as well as detection of ED‐1 and PECAM‐expression using immunohistochemistry. We show that the phosphate‐buffered fleeces have reduced release (p < 0.05) of the integrated gentamicin. However, all of the fleeces tested had a significant antimicrobial effect on the growth of Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa strains (p < 0.01). Among the fleeces tested, the new Jason G® fleece had the weakest but nevertheless sufficient antimicrobial effectiveness. Evaluation of the antibiotic effect in the prevention of an infection showed no differences between the applied fleeces. Following surgical implantation of fleece in the backs of Wistar rats we observed, on day 5 after implantation, an increase in cell infiltration and microvascularization with the phosphate‐buffered fleece as compared with conventional fleeces, which show necrotic cells on their surface. Unlike the acidic fleeces, on day 15 after implantation the pH–neutral fleece was resorbed widely. Here, we show that the new, pH–neutral, gentamicin‐containing fleece Jason G® exhibits good overall antimicrobial effectiveness against both gram‐positive and gram‐negative bacteria in vitro with improved degradation properties and microvasculature formation in vivo. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
Surface properties and blood compatibility of commercially available diamond‐like carbon coatings for cardiovascular devices
Authors: Fedel Mariangela , Motta Antonella , Maniglio Devid , Migliaresi Claudio
Published: December 2008

The aim of this study was to determine the relationships between the surface properties and blood compatibility of in‐use diamond‐like carbon (DLC) coatings for cardiovascular components. Commercially available DLC films were characterized with respect to surface topography and wettability, protein adsorption from human plasma, and platelets adhesion/activation. Fibrinogen (Fng) and human serum albumin (HSA) adsorbed onto the sample surfaces were in particular quantified as two of the main proteins involved in blood compatibility. A low tendency of platelets to spread and form aggregates onto the DLC‐coated surfaces has been described and related to a low Fng‐to‐HSA adsorption ratio. This study provides evidence that the rapid and tenacious binding of albumin molecules to DLC materials tends to passivate the surfaces and to inhibit Fng adsorption, thus imparting thromboresistance to the carbon coatings by rendering the surfaces less adhesive and activating for platelets. Albumin preferential adsorption was ascribed to high chemical heterogeneity of the DLC sample surfaces. The DLC films tested present a favorable behavior as regards blood compatibility with respect to platelet thrombus formation by reason of their surface properties. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
Analysis of bone mineral density and bone turnover in the presence of polymethylmethacrylate particles
Authors: Zilber S. , Lee S. W. , Smith R. L. , Biswal S. , Goodman S. B.
Published: December 2008

Polymethylmethacrylate (PMMA) particles generated from joint arthroplasties appear to contribute to aseptic implant loosening through inflammation‐induced periprosthetic osteolysis. However, osteolysis appears to be multifactorial; whether a direct link exists between PMMA particles and osteolysis in vivo is unproven. With the aim to define the relationship between PMMA particles and osteolysis, the authors analyzed the bone mineral density, using microCT scans preoperatively, the first day postoperatively and then every 7–10 days for 32 days, and bone turnover, using 18F‐fluoride positron emission tomography scanner (PET scan) at 8 weeks in four groups of mice that had undergone intramedullary femoral injection. The experimental group of five mice was injected with PMMA particles, and compared with two negative control groups (no injection and injection with the carrier, phosphate‐buffered saline) and one positive control group (injection of PMMA particles contaminated with endotoxin). There was no significant change in bone mineral density with addition of PMMA particles, and no evidence of osteolysis. However, bone turnover was increased in the presence of PMMA particles. Even though a direct link between PMMA particles and osteolysis was not found in the short term, PMMA particles appear to influence the regenerative capacity of bone. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
Host‐derived loss of dentin matrix stiffness associated with solubilization of collagen
Authors: Carrilho Marcela R. , Tay Franklin R. , Donnelly Adam M. , Agee Kelli A. , Tjäderhane Leo , Mazzoni Annalisa , Breschi Lorenzo , Foulger Stephen , Pashley David H.
Published: December 2008

Matrix metalloproteinases (MMPs) bound to dentin matrices are activated during adhesive bonding procedures and are thought to contribute to the progressive degradation of resin‐dentin bonds over time. The purpose of this study was to evaluate the changes in mechanical, biochemical, and structural properties of demineralized dentin treated with or without chlorhexidine (CHX), a known MMP‐inhibitor. After demineralizing dentin beams in EDTA or phosphoric acid (PA), the baseline modulus of elasticity (E) of each beam was measured by three‐point flexure. Specimens were pretreated with water (control) or with 2% CHX (experimental) and then incubated in artificial saliva (AS) at 37°C for 4 weeks. The E of each specimen was remeasured weekly and, the media was analyzed for solubilized dentin collagen at first and fourth week of incubation. Some specimens were processed for electron microscopy (TEM) immediately after demineralization and after 4 weeks of incubation. In EDTA and PA‐demineralized specimens, the E of the control specimens fell (p < 0.05) after incubation in AS, whereas there were no changes in E of the CHX‐pretreated specimens over time. More collagen was solubilized from PA‐demineralized controls (p < 0.05) than from EDTA‐demineralized matrices after 1 or 4 weeks. Less collagen (p < 0.05) was solubilized from CHX‐pretreated specimens demineralized in EDTA compared with PA. TEM examination of control beams revealed that prolonged demineralization of dentin in 10% PA (12 h) did not denature the collagen fibrils. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
GridMAT‐MD: A grid‐based membrane analysis tool for use with molecular dynamics
Authors: Allen William J. , Lemkul Justin A. , Bevan David R.
Published: December 2008

GridMAT‐MD is a new program developed to aid in the analysis of lipid bilayers from molecular dynamics simulations. It reads a GROMACS coordinate file and generates two types of data: a two‐dimensional contour plot depicting membrane thickness, and a polygon‐based tessellation of the individual lipid headgroups. GridMAT‐MD can also account for proteins or small molecules within the headgroups of the lipids, closely approximating their occupied lateral area. The program requires no installation, is fast, and is freely available. © 2008 Wiley Periodicals, Inc. J Comput Chem, 2009
Polarizable empirical force field for nitrogen‐containing heteroaromatic compounds based on the classical Drude oscillator
Authors: Lopes Pedro E. M. , Lamoureux Guillaume , Mackerell Alexander D.
Published: December 2008

The polarizable empirical CHARMM force field based on the classical Drude oscillator has been extended to the nitrogen‐containing heteroaromatic compounds pyridine, pyrimidine, pyrrole, imidazole, indole, and purine. Initial parameters for the six‐membered rings were based on benzene with nonbond parameter optimization focused on the nitrogen atoms and adjacent carbons and attached hydrogens. In the case of five‐member rings, parameters were first developed for imidazole and transferred to pyrrole. Optimization of all parameters was performed against an extensive set of quantum mechanical and experimental data. Ab initio data were used for the determination of initial electrostatic parameters, the vibrational analysis, and in the optimization of the relative magnitudes of the Lennard‐Jones (LJ) parameters, through computations of the interactions of dimers of model compounds, model compound‐water interactions, and interactions of rare gases with model compounds. The absolute values of the LJ parameters were determined targeting experimental heats of vaporization, molecular volumes, heats of sublimation, crystal lattice parameters, and free energies of hydration. Final scaling of the polarizabilities from the gas‐phase values by 0.85 was determined by reproduction of the dielectric constants of pyridine and pyrrole. The developed parameter set was extensively validated against additional experimental data such as diffusion constants, heat capacities, and isothermal compressibilities, including data as a function of temperature. © 2008 Wiley Periodicals, Inc. J Comput Chem 2009
Reduction of Egf signaling decides transition from crown to root in the development of mouse molars
Authors: Fujiwara Naoki , Akimoto Tadashi , Otsu Keishi , Kagiya Tadayoshi , Ishizeki Kiyoto , Harada Hidemitsu
Published: December 2008

Mouse, rat, and human molars begin to form their roots after the completion of crown morphogenesis. Though several signaling pathways and transcription factors have been implicated in the regulation of molar crown development, relatively little is known about the regulatory mechanisms involved in the transition from crown to root development. Tooth root formation is initiated by the development of Hertwig's epithelial root sheath (HERS) from the cervical loop in the enamel organ. In this study we examined the change in epidermal growth factor (Egf) signaling during this transition process. Immunohistochemical studies showed that the expression of Egf receptors in the enamel organ disappear gradually in the process and are not observed in HERS. Here, to examine the effect of Egf on the transition, we used the organ culture method to examine the root development. In the presence of Egf, stellate reticulum (SR) cells between the inner and outer epithelial layers in the enamel organ actively proliferated and maintained the enamel organ, and the formation of HERS was not observed. On the other hand, in either the absence of Egf or the presence of the inhibitor of Egf receptors, the SR cells disappeared and HERS formation started. Subsequently, root formation proceeded in the culture period. Therefore, disappearance of SR area may be a key event that controls the timing of onset of HERS formation, and Egf may be one of regulatory factors involved in the change from cervical loop epithelium to HERS during root development. J. Exp. Zool. (Mol. Dev. Evol.) 312B:486–494, 2009. © 2008 Wiley‐Liss, Inc.
Intracellular sAPP retention in response to Aβ is mapped to cytoskeleton‐associated structures
Authors: Henriques Ana Gabriela , Vieira Sandra Isabel , Crespo‐López Maria Elena , Guiomar de Oliveira Márcio A. , da Cruz e Silva Edgar F. , da Cruz e Silva Odete A.B.
Published: December 2008

Amyloid β (Aβ) contributes to neurodegeneration in Alzheimer's disease and provides a close association between molecular events and pathology, although the underlying molecular mechanisms are unclear. In the work described here, Aβ did not induce amyloid precursor protein (APP) expression, but APP processing/trafficking was markedly affected. In COS‐7 cells, Aβ provokes retention of intracellular sAPPα (isAPPα). Intracellular holo‐APP levels remain unchanged, and extracellular total sAPP increases, although extracellular sAPPα alone was not altered significantly. In primary neuronal cultures and PC12 cells, isAPP also increased, but this was mirrored by a decrease in extracellular total sAPP. The isAPP retention was particularly associated with the cytoskeletal fraction. The retention “per se” occurred in vesicular‐like densities, negative for a C‐terminal antibody and strongly positive for the 6E10 antibody, clearly showing abnormal intracellular accumulation of sAPPα in response to Aβ. Our data support a dynamic model for intracellular retention of sAPPα as an early response to Aβ exposure. Particularly noteworthy was the observation that removal of Aβ reversed the isAPP accumulation. Mechanistically, these findings disclose an attractive physiological response, revealing the capacity of cells to deal with adverse effects induced by Aβ. © 2008 Wiley‐Liss, Inc.