bluuebunny/crossref_metadata_2025 huggingface dataset:
Observation of the growth of carbon nanotubes prepared at low temperature
Authors: Gao Dawei , Liu Weiwei , Hou Li
Published: July 2008

Lack of information during the growth of carbon nanotubes has hindered efforts to understand the growth mechanism of these unique nanoscale structures. Here, we report that Multi‐walled carbon nanotubes with bamboo‐shaped structure may be synthesized by solvothermal method at 300°C using benzene as carbon source and Zn as catalyst. We have obtained direct experimental information on the growth under Transmission electron microscopy. It has been shown that all the compartments of bamboo‐like tube successively joined leading to the formation of regularly segmented nanobamboos. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of solvents on the hydrothermal formation of one‐dimensional magnesium hydroxide
Authors: Sun X. T. , Xiang L. , Zhu W. C. , Liu Q.
Published: July 2008

The influence of solvents on the hydrothermal formation of one‐dimensional (1D) magnesium hydroxide (Mg(OH)2) was investigated in this paper. Uniform 1D Mg(OH)2 with a length of 10‐20 μm, a width of 100‐200 nm and a preferential growth along [110] direction have been synthesized by treating magnesium oxysulfate (5Mg(OH)2·MgSO4·3H2O, abbreviated as 513MOS) nanowires in NaOH ethanol solution at 180 °C for 2.0 h. The experimental results indicated that the solvent of ethanol and NaOH concentration were essential for the conversion of 513MOS nanowires to 1D Mg(OH)2. The slow release of MgSO4 from 513MOS and the heterogenous precipitation of Mg(OH)2 at the defects left by MgSO4 dissolution promoted the formation of 1D Mg(OH)2. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Growth and characterization of strontium tartrate pentahydrate crystals
Authors: Firdous A. , Quasim I. , Ahmad M. M. , Kotru P. N.
Published: July 2008

Silica gel impregnated with L‐tartaric acid and using strontium nitrate as the second reactant leads to the growth of well faceted strontium tartrate pentahydrate single crystals.The morphological developmen and internal cell dimensions are observed to be different from the ones reported in the literature for strontium tartrate trihydrate crystals. The crystals are characterized using XRD, CH analysis, SEM, FTIR spectroscopy and thermoanalytical techniques. The crystals are observed to be thermally stable upto about 105°C but thereafter start decomposing and ejecting water of hydration at various stages, finally reducing to strontium oxide. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Raman scattering characterization of Mn composition and strain in Ga1–xMnxSb/GaSb epitaxial layers
Authors: Islam M. R. , Chen N. F. , Yamada M.
Published: July 2008

Raman scattering (RS) experiments have been performed for simultaneous determination of Mn composition and strain in Ga1–xMnxSb thin films grown on GaSb substrate by liquid phase epitaxy technique. The Raman spectra obtained from various Ga1–xMnxSb samples show only GaSb‐like phonon modes whose frequency positions are found to have Mn compositional dependence. With the combination of epilayer strain model, RS and energy dispersive x‐ray (EDX) experiments, the compositional dependence of GaSb‐like LO phonon frequency is proposed both in strained and unstrained conditions. The proposed relationships are used to evaluate Mn composition and strain from the Ga1–xMnxSb samples. The results obtained from the RS data are found to be in good agreement with those determined independently by the EDX analysis. Furthermore, the frequency positions of MnSb‐like phonon modes are suggested by reduced‐mass model. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The effect of Si/Al ratio of ZSM‐5 zeolite on its morphology, acidity and crystal size
Authors: Shirazi L. , Jamshidi E. , Ghasemi M. R.
Published: July 2008

ZSM‐5 zeolite crystal with different Si/Al molar ratios in the range of 10‐50 was synthesized using sodium silicate, aluminum sulfate and tetrapropylammonium bromide (TPA‐Br) as the organic template. The produced samples were characterized using XRD, FT‐IR, SEM and EDX techniques. All synthesized samples were found to be ZSM‐5 zeolite as confirmed by XRD and supported by FT‐IR. SEM results showed that ZSM‐5 synthesized with different Si/Al molar ratios had different morphologies and particle sizes. It was found that the average ZSM‐5 crystal size increased as Si/Al molar ratio increased. Thermogravimetric‐difference thermal analysis (TG‐DTA) technique was also used to measure the amount of template occluded inside the crystal pore. The synthesized Na‐ZSM‐5 was transformed into its acidic form, i.e., H‐ZSM‐5 using ion exchange method with ammonium nitrate solution. The H‐ZSM‐5 acidity was determined by NH3‐TPD. These results showed that different Si/Al molar ratios have effect on surface acidity of samples. The surface areas of the H‐ZSM‐5 were measured using BET method and the results showed that, decrease in Si/Al ratio, decreased the surface area. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
How do crystal lattice contacts reveal protein crystallization mechanism?
Authors: Nanev Christo N.
Published: July 2008

The nature of crystal lattice contacts is discussed because they reflect the selection of the most appropriate (for the given set of conditions) contact patches on the surface of protein molecules. The conclusion is that, along with chemical composition, the protein structure at the crystal lattice contacts is the key to crystallization behavior. The reason is that most stable are conformations, which do not only maximize the number of the bonds but simultaneously minimize van der Waals repulsions. A plausible explanation of the crystallization slot that exists for proteins is given on this basis. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Studies on multiphased mixed crystals of NaCl, KCl and KI
Authors: Priya M. , Mahadevan C. K.
Published: July 2008

Multiphased mixed crystals of NaCl, KCl and KI were grown by the melt method, for the first time. Densities and refractive indices of all the grown crystals were determined and used for the estimation of the composition in the crystal. Atomic absorption spectroscopic measurements were done to estimate the metal atom contents in the crystal. Lattice parameters and thermal parameters (Debye‐Waller factor, mean square amplitude of vibration, Debye temperature and Debye frequency) were determined from the X‐ray powder diffraction data. DC and AC electrical measurements were done at various temperatures ranging from 40 to 150°C. Activation energies were also estimated. The observed lattice parameters showed that the system exhibits three phases each nearly corresponds to NaCl, KCl and KI. The thermal and electrical parameters show a highly nonlinear bulk composition dependence. Results are reported. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A Highly Active Water‐Soluble Cross‐Coupling Catalyst Based on Dendritic Polyglycerol N‐Heterocyclic Carbene Palladium Complexes
Authors: Meise Markus , Haag Rainer
Published: July 2008

A new water‐soluble polyglycerol derivative functionalized with N‐heterocyclic carbene palladium complexes was prepared and applied as catalyst for Suzuki cross‐coupling reactions in water. The complex displays a metal loading of around 65 metal centers per dendrimeric molecule, which is estimated to contain 130 chelating groups and thus corresponds approximately to the formation of 2:1 NHC/metal complexes. Monomeric analogues were also synthesized to validate the reactivity of the dendritic catalyst. Both types of catalysts were tested with various aryl bromides and arylboronic acids. Turnover frequencies of up to 2586 h−1 at 80 °C were observed with the dendritic catalyst along with turnover numbers of up to 59 000, which are among the highest turnover numbers reported for polymer‐supported catalysts in neat water. The dendritic catalyst could be used (reused) in five consecutive reactions without loss in activity.
Real‐time chaotic circuit stabilization via inverse optimal control
Authors: Jimenez Alexander , Sanchez Edgar N. , Chen Guanrong , Perez Jose P.
Published: July 2008

In this paper, an efficient approach is developed for real‐time global asymptotic stabilization of the chaotic Chen's circuit, as a typical example for chaotic circuit control. Based on a recently introduced methodology of inverse optimal control for nonlinear systems, a very simple stabilization control law, a linear state feedback, is electronically implemented for the desired global asymptotic stabilization. Both Chen's chaotic system and the designed controller are synthesized and realized by analog electronic components, with the aim of evaluating the physical performance of the real‐time control law and demonstrating the practicality of the control method, which is robust to some input uncertainties. Copyright © 2008 John Wiley & Sons, Ltd.
A configuration for realizing floating, linear, voltage‐controlled resistance, inductance and FDNC elements
Authors: Senani R. , Bhaskar D. R. , Gupta S. S. , Singh V. K.
Published: July 2008

A configuration using current feedback amplifiers has been presented, which is capable of realizing linear, positive/negative voltage‐controlled resistance, voltage‐controlled inductance and voltage‐controlled frequency‐dependent negative conductance in floating form (and thereby, also in grounded form) from the same structure. The workability of the proposed configuration has been demonstrated by hardware implementation results using AD 844‐type current feedback op‐amps (CFOAs) and BFW‐11‐type JFETs and the workability in high‐frequency range has been demonstrated by SPICE simulation using CMOS CFOAs. Copyright © 2008 John Wiley & Sons, Ltd.
Flow cytometry histograms: Transformations, resolution, and display
Authors: Novo David , Wood James
Published: July 2008

Flow cytometry data analysis routinely includes the use of one‐ or two‐parameter histograms to visualize the data. These histograms have traditionally been plotted with either a linear or logarithmic scale. However, the recent trend of performing the logarithmic conversion in software has made apparent some limitations of the traditional visual presentation of logarithmic data. This review discusses the mathematics of presenting data on a histogram and emphasizes the difference between scaling and binning. The review introduces the concept of an effective resolution to describe how the bin width changes in a variable bin‐width histogram. The change in effective resolution is used to explain the commonly observed valley and picket fencing artifacts. These result from the effective resolution of the display histogram being too high for the data being presented. Recently, several different binning transformations have been described that are becoming more popular because they allow one to view a large dynamic range of data on a single plot, while allowing the display of negative data values. While each of the transforms is based upon different equations, they all exhibit very similar properties. All of the transforms bin the data logarithmically at high channel values and linearly at low channel values. The linear scaling of the lower channels serves to limit the effective resolution of the histogram, thus minimizing the valley and picket fencing artifacts. The newer transformations are not without their own limitations and recommendations for the appropriate manner of presenting flow cytometry data using these newer transformations are discussed. © 2008 International Society for Advancement of Cytometry
Antigen‐specific B cell detection reagents: Use and quality control
Authors: Moody M. Anthony , Haynes Barton F.
Published: July 2008

Tests for immunoglobulin reactivity with specific antigens are some of the oldest and most used assays in immunology. With efforts to understand B cell development, B cell dysregulation in autoimmunity, and to generate B cell vaccines for infectious agents, investigators have found the need to understand the ontogeny and regulation of epitope‐specific B cell responses. The synchrony between surface and secreted antibodies for individual B cells has led to the development of reagents and techniques to identify antigen‐specific B cells via reagent interactions with the B cell receptor complex. B cell antigen‐specific reagents have been reported for model systems of haptens, for whole proteins, and for identification of double stranded (ds) DNA antibody‐producing B cells using peptide mimics. Here we provide an overview of reported techniques for the detection of antigen‐specific B cell responses via secreted antibody or by the surface B cell receptor and briefly discuss our recent work developing a panel of reagents to probe the B cell response to HIV‐1 envelope. We also present an analysis of strengths and weaknesses of various methods for flow cytometric analysis of antigen‐specific B cells. © 2008 International Society for Advancement of Cytometry
Development of an automated analysis system for data from flow cytometric intracellular cytokine staining assays from clinical vaccine trials
Authors: Shulman Nicholas , Bellew Matthew , Snelling George , Carter Donald , Huang Yunda , Li Hongli , Self Steven G. , McElrath M. Juliana , De Rosa Stephen C.
Published: July 2008

Intracellular cytokine staining (ICS) by multiparameter flow cytometry is one of the primary methods for determining T‐cell immunogenicity in HIV‐1 clinical vaccine trials. Data analysis requires considerable expertise and time. The amount of data is quickly increasing as more and larger trials are performed, and thus there is a critical need for high‐throughput methods of data analysis. A web‐based flow cytometric analysis system, LabKey Flow, was developed for the analyses of data from standardized ICS assays. Using a gating template created manually in commercially available flow cytometric analysis software, the system automatically compensates and analyzes all data sets. Quality control queries were designed to identify potentially incorrect sample collections. Comparison of the semiautomated analysis performed by LabKey Flow and the manual analysis performed using FlowJo software demonstrated excellent concordance (concordance correlation coefficient > 0.990). Manual inspection of the analyses performed by LabKey Flow for eight‐color ICS data files from several clinical vaccine trials indicated that template gates can appropriately be used for most data sets. Thus, the semiautomated LabKey Flow analysis system can accurately analyze large ICS data files. Routine use of the system does not require specialized expertise. This high‐throughput analysis will provide great utility for rapid evaluation of complex multiparameter flow cytometric measurements collected from large clinical trials. © 2008 International Society for Advancement of Cytometry
Comparative study of human erythrocytes by digital holographic microscopy, confocal microscopy, and impedance volume analyzer
Authors: Rappaz Benjamin , Barbul Alexander , Emery Yves , Korenstein Rafi , Depeursinge Christian , Magistretti Pierre J. , Marquet Pierre
Published: July 2008

Red blood cell (RBC) parameters such as morphology, volume, refractive index, and hemoglobin content are of great importance for diagnostic purposes. Existing approaches require complicated calibration procedures and robust cell perturbation. As a result, reference values for normal RBC differ depending on the method used. We present a way for measuring parameters of intact individual RBCs by using digital holographic microscopy (DHM), a new interferometric and label‐free technique with nanometric axial sensitivity. The results are compared with values achieved by conventional techniques for RBC of the same donor and previously published figures. A DHM equipped with a laser diode (λ = 663 nm) was used to record holograms in an off‐axis geometry. Measurements of both RBC refractive indices and volumes were achieved via monitoring the quantitative phase map of RBC by means of a sequential perfusion of two isotonic solutions with different refractive indices obtained by the use of Nycodenz (decoupling procedure). Volume of RBCs labeled by membrane dye Dil was analyzed by confocal microscopy. The mean cell volume (MCV), red blood cell distribution width (RDW), and mean cell hemoglobin concentration (MCHC) were also measured with an impedance volume analyzer. DHM yielded RBC refractive index n = 1.418 ± 0.012, volume 83 ± 14 fl, MCH = 29.9 pg, and MCHC 362 ± 40 g/l. Erythrocyte MCV, MCH, and MCHC achieved by an impedance volume analyzer were 82 fl, 28.6 pg, and 349 g/l, respectively. Confocal microscopy yielded 91 ± 17 fl for RBC volume. In conclusion, DHM in combination with a decoupling procedure allows measuring noninvasively volume, refractive index, and hemoglobin content of single‐living RBCs with a high accuracy. © 2008 International Society for Advancement of Cytometry
Association of glucose transporter 1 polymorphisms with type 2 diabetes in the Tunisian population
Authors: Makni K. , Mnif F. , Boudawara M. , Hamza N. , Rekik N. , Abid M. , Rebaï A. , Jarraya F. , Granier C. , Ayadi H.
Published: July 2008

Background

T2DM is a complex metabolic disease. Genetic studies on T2DM have been of little help so far because several genetic association studies have shown conflicting results. In this study, we report the findings of a case‐control study on three SNPs in the GLUT1 gene. For this, we investigated the association of GLUT1 genotypes and haplotypes with T2DM.

Research Design and Methods

All 273 T2DM subjects (cases) and 343 healthy subjects (controls) were genotyped using the polymerase chain reaction restriction fragment length polymorphism.

Results

Results showed that the GT genotype ofXbaISNP could increase the risk of susceptibility to T2DM to 2.4 and that TAT is a ‘risk haplotype’ conferring a risk of 3.4 to T2DM.

Conclusion

The TAT haplotype of the GLUT1 gene confers susceptibility to T2DM in the Tunisian population. Copyright © 2008 John Wiley & Sons, Ltd.
Increased renal collagen cross‐linking and lipid accumulation in nephropathy of Zucker diabetic fatty rats
Authors: Li Yuhao , Qi Yanfei , Kim Moon Sun , Xu Kevin Zhe‐Yang , Huang Tom Hsun‐Wei , Rong Xianglu , Murray Michael , Yamahara Johji
Published: July 2008

Background

Zucker diabetic fatty (ZDF) rat is a genetic model of type 2 diabetes and obesity. The mechanism underlying nephropathy in ZDF rats, however, remains unclear.

Methods

ZDF rats were compared to age‐matched Zucker lean (ZL) rats. Physiological and blood biochemical parameters, renal glomerular cross‐sectional area (hematoxylin‐eosin staining), fibrosis (van Giesen staining), collagen composition (Sircol Collagen Assay), lipids (enzymatic method) and mRNA expression (RT‐PCR) were determined.

Results

ZDF rats showed an increase in renal‐insoluble collagen content and the ratio of renal‐insoluble to salt‐soluble collagen (2‐ and 1.5‐fold of the control animals). There were increases in renal glomerulosclerosis and interstitial fibrosis in ZDF rats (increased to 2‐fold) in the glomerular mesangium and tubulointerstitium, and increased glomerular area. Renal triglyceride accumulated to greater than 2‐fold of those levels in ZL rats. These changes were accompanied by hypoalbuminemia, and elevated plasma blood urea nitrogen and uric acid levels. Gene profiling showed increased expression of transcripts encoding the glomerulosclerotic mediator collagens I and IV, plasminogen activator inhibitor‐1, transforming growth factor‐β1, and angiotensin II type 1 receptor in ZDF rat kidney. Moreover, renal expression of mRNAs encoding sterol regulatory element‐binding protein‐1, a nuclear transcription factor that activates genes involved in fatty acid synthesis, and acetyl‐CoA carboxylase, a key enzyme that mediates fatty acid synthesis, was increased in ZDF rats.

Conclusions

Our findings suggest that dysregulated gene expression may result in increased renal collagen cross‐linking and lipid accumulation, that may be associated with development of nephropathy in the animal model of type 2 diabetes and obesity. Copyright © 2008 John Wiley & Sons, Ltd.
Prevention of insulin resistance and beta‐cell loss by abrogating PKCε‐induced serine phosphorylation of muscle IRS‐1 in Psammomys obesus
Authors: Mack Esther , Ziv Ehud , Reuveni Hadas , Kalman Rony , Niv Masha Y. , Jörns Anne , Lenzen Sigurd , Shafrir Eleazar
Published: July 2008

Objective

Psammomys obesus gerbil exhibits PKCε over‐expression on high‐energy (HE) diet. Muscle insulin receptor (IR) signalling and tyrosine kinase activity are inhibited eliciting insulin resistance. We aimed at preventing diabetes by inhibiting PKCε‐induced serine phosphorylation of IRS‐1 with novel PKCε abrogating peptides.

Research design

PKCε abrogating peptides were copied from catalytic domain of PKC molecule (PCT patent IL2006/000755). Psammomys fed a diabetogenic HE diet received i.p. peptides KCe‐12 and KCe‐16 (18 mg/kg) on days 0, 7 and 14 controls received peptide solvent.

Results

Food consumption and animal weight remained unchanged. On day 16, non‐fasting blood glucose levels returned to normal (90 ± 5 versus 347 ± 16 mg/dL in untreated controls). Hyperinsulinemia fell from 584 ± 55 to 180 ± 22 mU/L. Western blot analysis showed that the increased phosphoserine636, 639 content on IRS‐1 in gastrocnemius muscle of diabetic animals was reduced three fold, the PKB/AKT activity increased two fold and muscle GLUT4 tended to increase, compared with controls. Likewise, administration of KCe‐12 prior to placing the HE diet prevented the onset of diabetes. KCe‐12 treatment did not reduce muscle PKCε level. Damage and loss of insulin in pancreatic beta cells on HE diet were prevented by KCe‐12, as shown in micrographs of islet hematoxylin‐eosin staining and insulin immunostaining. The preserved secretory function enabled Psammomys to normalize glucose homeostasis.

Conclusions

KCe‐16 and KCe‐12 peptides derived from PKCε substrate‐binding region prevented the nutritional diabetes and protected muscle IRS‐1 from PKCε‐induced serine phosphorylation, abrogating the insulin‐signalling impediment in the Psammomys model of type 2 diabetes. Anti‐diabetic peptides may lead to novel modalities preventing human overnutrition‐induced insulin resistance and diabetes. Copyright © 2008 John Wiley & Sons, Ltd.
Plasma glycooxidation protein products in type 2 diabetic patients with nephropathy
Authors: Piwowar Agnieszka , Knapik‐Kordecka Maria , Szczecińska Joanna , Warwas Maria
Published: July 2008

Background

In diabetes mellitus, hyperglycaemia accelerates non‐enzymatic glycation and oxidative stress leading to damage of macromolecules, among others proteins. This manifests in the increased levels of advanced glycation end products (AGE) and advanced oxidation protein products (AOPP).

Objectives

To assess the plasma levels of AGE and AOPP in the patients with type 2 diabetes mellitus (T2DM) and to estimate its relation and connection with the degree of nephropathy.

Material and Methods

In 121 diabetic patients and 22 healthy people plasma levels of AGE and AOPP were determined with fluorimetric and spectrophotometric methods, respectively. To estimate nephropathy stage, albumin/creatinine ratio was calculated on the basis of albumin and creatinine concentrations in early morning urine samples.

Results

Diabetic patients had significantly higher levels of AGE and AOPP in comparison to healthy people. Both parameters were increasing progressively from normoalbuminuria, through microalbuminuria to macroalbuminuria. Statistically, the most significant differences were observed in AOPP concentration between separated groups. AGE fluorescence was significantly different on the same low, statistical level between patients with normoalbuminuria when compared to those with micro‐ and macroalbuminuria. Plasma AGE correlated significantly with urinary albumin/creatinine ratio whereas AOPP correlated with plasma creatinine level.

Conclusions

The connection between plasma levels of both glycooxidation protein products—AGE and AOPP with nephropathy severity, measured by the degree of albuminuria, in T2DM patients was observed. We can suggest that the AOPP better reflect the progression of kidney damage than AGE in examined diabetic patients. Copyright © 2008 John Wiley & Sons, Ltd.
Conditional activation of a single‐copy L1 transgene in mice by Cre
Authors: An Wenfeng , Han Jeffrey S. , Schrum Christina M. , Maitra Anirban , Koentgen Frank , Boeke Jef D.
Published: July 2008

The synthetic L1 retrotransposon, ORFeus, is useful for probing mechanisms of L1 retrotransposition in vivo and for genome‐wide mouse mutagenesis because of its high level of activity. To achieve controlled activation of ORFeus in mice, we constructed ORFeusLSL, in which ORFeus coding sequences were separated from the promoter by a loxP‐β‐geo‐stop‐loxP (LSL) cassette, and derived transgenic mouse lines containing single‐copy ORFeusLSL. We observed tissue‐specific ORFeus activation by crossing ORFeusLSL to various Cre‐expressing lines, specifically in the germ line or the pancreas, providing definite evidence that all host factors and machinery required posttranscriptionally for L1 retrotransposition are available in somatic tissues in living animals. Notably, the single‐copy ORFeus transgene is about threefold more active per copy than a previously described multicopy ORFeus transgene in the germ line and even more active somatically. This conditional transgenic ORFeus mouse model should allow further exploration of posttranscriptional cellular requirements for L1 retrotransposition and facilitate the development of ORFeus mouse lines suitable for in vivo mutagenesis. genesis 46:373–383, 2008. © 2008 Wiley‐Liss, Inc.
Generation and characterization of a Gdf1 conditional null allele
Authors: Bengtsson Henrik , Epifantseva Irina , Åbrink Magnus , Kylberg Annika , Kullander Klas , Ebendal Ted , Usoskin Dmitry
Published: July 2008

Growth differentiation factor‐1 (GDF1), a TGF‐β superfamily member, participates in early embryo patterning. Later functions are implied by the Gdf1 expression in the peripheral and central nervous system. Such roles of the gene have been difficult to study, because Gdf1 null mice die during late embryogenesis. Here, we report the production of a mouse carrying a conditional Gdf1 allele, with exon 2 flanked by loxP sites. Crossing these mice with CaMKIIα‐Cre mice resulted in Gdf1 ablation in the forebrain postnatally. Such mice displayed no behavioral changes or altered expression levels in a set of hippocampal genes examined. However, excision of the floxed Gdf1 exon caused increased expression of the remaining part of the bicistronic Uog1‐Gdf1 transcript in the hippocampus. This indicates that the transcript level is regulated by a negative feedback‐loop, sensing presence of either the protein or the mRNA region encoded by Gdf1 exon 2. genesis 46:368–372, 2008. © 2008 Wiley‐Liss, Inc.
Bis(cycloheptatrienyl) Derivatives of the First‐Row Transition Metals: Variable Hapticity of the Cycloheptatrienyl Ring
Authors: Wang Hongyan , Xie Yaoming , King R. Bruce , Schaefer Henry F.
Published: July 2008

Extrapolation from ferrocene and dibenzenechromium suggests the currently unknown 18‐electron sandwich compound (η7‐C7H7)2Ti as a possible stable molecule. However, density functional theory (DFT) methods using the B3LYP and BP86 functionals predict (η7‐C7H7)2Ti to distort by ring slippage to give a singlet 16‐electron complex (η7‐C7H7)Ti(η5‐C7H7) having an uncomplexed C=C double bond in one of the C7H7 rings but otherwise closely related to the known (η7‐C7H7)Ti(η5‐C5H5). The situation is similar with (C7H7)2V except that the corresponding structures have doublet spin multiplicity. However, an analogous (η7‐C7H7)Cr(η5‐C7H7) structure is not found for chromium. Instead the most stable (C7H7)2Cr structure is a singlet d0 six‐coordinate formally CrVI complex with two tridentate cyclopropyldivinyl C7H7 ligands. The latter rearrangement of the C7H7 rings bonded to chromium can involve initially a (η6‐C7H7)2Cr diradical sandwich compound followed by a bis(η5‐norcaradienyl)Cr intermediate. For the later first‐row transition metals the lowest energy (C7H7)2M structures are predicted to be doublet (η7‐C7H7)Mn(η3‐C7H7) rather than (η5‐C7H7)2Mn for manganese, singlet cis and trans structures (η5‐C7H7)2Fe for iron, doublet (η3‐C7H7)2Co for cobalt, and two singlet (η3‐C7H7)2Ni stereoisomers for nickel.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Slow Magnetic Relaxation in CoIICuII Coordination Oligomer Built into Mesoporous Material
Authors: Cangussu Danielle , Nunes Wallace C. , Pereira Cynthia L. M. , Pedroso Emerson F. , Mazali Italo O. , Knobel Marcelo , Alves Oswaldo L. , Stumpf Humberto O.
Published: July 2008

The ferrimagnetic system CoCu(opba) [opba = ortho‐phenylenebis(oxamato)] was employed to prepare a traditional chain [CoCu(opba)]·4H2O (1) and a nanocomposite by incorporation in porous Vycor glass (PVG). This nanocomposite was made by first anchoring [Bu4N]2[Cu(opba)] on PVG [PVG‐Cu (2)] and then treating it “in situ” with cobalt(II) acetate to obtain the nanomagnet PVG‐CuCo (3). Magnetic measurements show that 1 consists of a one‐dimensional ferrimagnet with strong intrachain antiferromagnetic coupling and weak interchain interactions that result in spin‐glass behavior below 3.5 K. Nanocomposite 3 presents ferrimagnetic chains limited by the nanopore size, which leads to a slow relaxation of the magnetization following Arrhenius' law, frequency dependence for in‐phase and out‐of‐phase susceptibility, and hysteresis below the blocked regime temperature (< 6 K). These features are characteristics of single‐chain magnets (SCM).(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Cobaltocenium [1,2,5]Thiadiazolo[3,4‐c][1,2,5]thiadiazolidyl: Synthesis, Structure, and Magnetic Properties
Authors: Konchenko Sergey N. , Gritsan Nina P. , Lonchakov Anton V. , Irtegova Irina G. , Mews Ruediger , Ovcharenko Victor I. , Radius Udo , Zibarev Andrey V.
Published: July 2008

Cobaltocene, [CoII(η5‐C5H5)2], readily reduced [1,2,5]thiadiazolo[3,4‐c][1,2,5]thiadiazole (2) to the [1,2,5]thiadiazolo[3,4‐c][1,2,5]thiadiazolidyl radical anion (1) which was isolated in the form of the thermally stable salt [CoIII(η5‐C5H5)2][1] (5) in 93 % yield. The XRD structure of 5 displays layers of radical anions 1, with S···N contacts of 358.2 and 366.0 pm between neighboring species. The salt was further characterized by ESR spectroscopy in the solid state as well as in solution. The temperature dependence of its magnetic susceptibility (χ) in the range of 2–300 K with a maximum at (9.7 ± 0.5) K indicates antiferromagnetic ordering of the spin system. The magnetic structure of 5 was analyzed in terms of dimeric exchange integrals calculated by a spin‐unrestricted broken‐symmetry approach at the DFT/UB3LYP/6‐31+G(d) level of theory and was found to be 2D. Further analysis of the χ(T) dependence was performed by using the low‐ and high‐temperature series expansion methods for the S = 1/2 square lattice antiferromagnetic Heisenberg model. The exchange interactions between radical anions 1 were estimated to be J = (–4.2 ± 0.7) cm–1. With the general form of the Van Vleck equation for a [3 × 4] grid of spins 1/2, the best fit of the experimental χ(T) was achieved with J1 = –5.0 cm–1 and J2 = –0.23 cm–1. Thus, the exchange interactions in 5 are stronger than those observed for previously studied salts of 1. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Vicarious Nucleophilic Substitutions of Hydrogen in 1,1,1‐Trifluoro‐N‐[oxido(phenyl)(trifluoromethyl)‐λ4‐sulfanylidene]methanesulfonamide
Authors: Lemek Tadeusz , Groszek Grażyna , Cmoch Piotr
Published: July 2008

1,1,1‐Trifluoro‐N‐[oxido(phenyl)(trifluoromethyl)‐λ4‐sulfanylidene]methanesulfonamide reacts with carbanions bearing a leaving group to give vicarious nucleophilic substitution (VNS) of hydrogen products with moderate yields. This is the first example of the VNS process at a benzene ring activated by an electron‐withdrawing group other than a nitro group. The orientation of the substitution is exclusivelypara. Findings open a large possibility for exploration of the scope of the VNS reaction on to compounds activated with sulfur‐based electron‐withdrawing groups. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
A Topological View of Isomeric Dendrimers
Authors: Schubert Dirk , Corda Mirza , Lukin Oleg , Brusilowskij Boris , Fiškin Evgenij , Schalley Christoph A.
Published: July 2008

A topological approach to the analysis of isomeric dendrimers by considering their molecular graphs has been applied to correlate various properties of a series of new sulfonimide‐based isomeric dendrimers with their structures. According to this approach isomeric dendrimers are referred to as either isographic, that is, having the same graph, or non‐isographic, that is, having different graphs. Six sets of non‐isographic isomeric dendrimers with four to ten peripheral groups and one set of three isographic isomers with eight peripheral groups have been designed, synthesized and investigated with regard to their melting, solubility, separation, NMR spectroscopic and mass spectrometric characteristics. The results are discussed in the light of the graph‐dependent and‐independent properties of the isomers. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
2‐(3‐Pyrrolin‐1‐yl)‐1,4‐naphthoquinones: Photoactivated Alkylating Agents
Authors: Aponick Aaron , Dietz Amber L. , Pearson William H.
Published: July 2008

The preparation of 2‐(3‐pyrrolin‐1‐yl)‐1,4‐naphthoquinones and a study of their use as photoactivated alkylating agents is reported. The title compounds were easily synthesized by conjugate addition of the corresponding 3‐pyrrolines to various naphthoquinones. Upon exposure to ambient room light, the compounds undergo an internal redox reaction to form 2‐(pyrrol‐1‐yl)‐1,4‐hydroquinones, which are activated for nucleophilic addition by an SN1 azafulvene mechanism. Control experiments demonstrated that the redox reaction is triggered by light and that the nucleophilic addition does not proceed before this activation occurs.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Controlling the mechanics and nanotopography of biocompatible scaffolds through dielectrophoresis with carbon nanotubes
Authors: Lu Yu‐Lun , Cheng Chao‐Min , LeDuc Philip R. , Ho Mon‐Shu
Published: July 2008

Creating a biocompatible carbon‐nanotube polymer scaffold is an area that has a number of potential applications. Herein, a dielectrophoretic approach was pursued to integrate carbon nanotubes into a polymeric material for fabricating a nanoscale composite scaffold with increased and controllable mechanical strength. The adhesion force, which combines the surface energy of the sample and the interfacial energy between the tip and sample, was estimated to be 55.39 ± 6.72 nN away from the center of the protrusions at a distance of 0.5 μm while being 24.01 ± 4.45 nN at the center. The adhesion force for the center of the cavities was 42.47 ± 6.91 and 88.21 ± 15.05 nN at 0.5 μm away from the center. NIH 3T3 fibroblast cells were then utilized to test the cellular biocompatibility of this multiwalled carbon nanotubes (MWCNTs) film. Cells were cultured on the surface and then their attachment, spreading, and proliferation behaviors were observed. This nanotube‐polymer scaffolding approach has a wide range of potential applications including in complex device fabrication as well as in developing biomimetic and tissue engineering scaffolds, and artificial organs.
Spatial analysis of relative risk of lip cancer in Iran: a Bayesian approach
Authors: Kavousi A. , Meshkani M. Reza , Mohammadzadeh M.
Published: July 2008

Providing a geographical map for rates of mortality, incidence, or prevalence of various diseases is of great importance for national health authorities. The relative risks are used to uncover the rate of incidence for different diseases. In the classical approach, the relative risk is often estimated under the assumption of independence between geographical areas. However, this assumption is not always substantiated in field studies, particularly in the case of health variables which may be strongly correlated due to common risk factors for adjacent areas. Such a dependence which is a function of distance between sample sites is called spatial correlation. In this paper, we account for such a dependence in evaluating the relative risk. This is undertaken by employing a hierarchical Bayesian approach. The proposed method is illustrated by a real example of lip cancer in Iran. The estimated relative risks and their standard errors (SEs) are computed. The distributional map of the disease and its SE are provided. Copyright © 2008 John Wiley & Sons, Ltd.
Comparison of three expert elicitation methods for logistic regression on predicting the presence of the threatened brush‐tailed rock‐wallaby Petrogale penicillata
Authors: O'Leary Rebecca A. , Choy Samantha Low , Murray Justine V. , Kynn Mary , Denham Robert , Martin Tara G. , Mengersen Kerrie
Published: July 2008

Numerous expert elicitation methods have been suggested for generalised linear models (GLMs). This paper compares three relatively new approaches to eliciting expert knowledge in a form suitable for Bayesian logistic regression. These methods were trialled on two experts in order to model the habitat suitability of the threatened Australian brush‐tailed rock‐wallaby (Petrogale penicillata). The first elicitation approach is a geographically assisted indirect predictive method with a geographic information system (GIS) interface. The second approach is a predictive indirect method which uses an interactive graphical tool. The third method uses a questionnaire to elicit expert knowledge directly about the impact of a habitat variable on the response. Two variables (slope and aspect) are used to examine prior and posterior distributions of the three methods. The results indicate that there are some similarities and dissimilarities between the expert informed priors of the two experts formulated from the different approaches. The choice of elicitation method depends on the statistical knowledge of the expert, their mapping skills, time constraints, accessibility to experts and funding available. This trial reveals that expert knowledge can be important when modelling rare event data, such as threatened species, because experts can provide additional information that may not be represented in the dataset. However care must be taken with the way in which this information is elicited and formulated. Copyright © 2008 John Wiley & Sons, Ltd.
Modelling of nitrogen dioxide (NO2) and fine particulate matter (PM10) air pollution in the metropolitan areas of Barcelona and Bilbao, Spain
Authors: Lertxundi‐Manterola Aitana , Saez Marc
Published: July 2008

Ecological studies in epidemiology present some limitations on assessing the exposure of environmental factors. The main objective of this study was to describe a statistical methodology that could help on more accurately assessing the relationship between air pollution and health responses at very small spatial scale.

In particular, we modelled the spatial distribution of nitrogen dioxide (NO2) and of particles with a diameter of less than 10 µm in two study areas, the metropolitan areas of Barcelona (MABa) and Bilbao (MABi). The areas chosen for this project can be distinguished for having similar population density and urban surface, as well as high road traffic intensity. The geographical variability of the pollutants could differ greatly due to very different orographic and climatic conditions.

Three contributions of this study could be mentioned. First of all, the spatial distribution of the values of each air pollutant was spread over the entire study region on a small area basis, that is census track in our case. Secondly, a stochastic interpolation method, kriging, was used. Thirdly, instead of estimating the average value of the pollutant at the centroid of the area for the entire study period, the value was estimated for each and every day of the corresponding period.

As regards the main results, in both areas it can be observed that those census tracks with a greater concentration of pollutants are those that were estimated more accurately. This suggests the existence of a persistent emission source in those tracks, very probably those roads with greater road traffic intensity. Copyright © 2008 John Wiley & Sons, Ltd.
Semiparametric M‐quantile regression for estimating the proportion of acidic lakes in 8‐digit HUCs of the Northeastern US
Authors: Pratesi Monica , Ranalli M. Giovanna , Salvati Nicola
Published: July 2008

Between 1991 and 1995, the Environmental Monitoring and Assessment Program of the US Environmental Protection Agency conducted a survey of lakes in the Northeastern states of the US to determine the ecological condition of these waters. Here, to this end, we want to obtain estimates of the proportion of lakes at (high) risk of acidification or acidified already for each 8‐digit hydrologic unit code (HUC) within the region of interest. Sample sizes for the 113 HUCs are very small and 27 HUCs are not even observed. Therefore, small area estimation techniques should be invoked for the estimation of the distribution function of acid neutralizing capacity (ANC) for each HUC. The procedure is based on a semiparametric M‐quantile regression model in which ANC depends on elevation and the year of the survey linearly, and on the geographical position of the lake through an unknown smooth bivariate function estimated by low‐rank thin plate splines. Copyright © 2008 John Wiley & Sons, Ltd.
Eating disorders and disordered eating in Israel: An updated review
Authors: Latzer Yael , Witztum Eliezer , Stein Daniel
Published: July 2008

Israel presents a unique opportunity to study the role of socio‐cultural parameters in the development of mental disturbances because of the exceptional diversity of the Israeli society. In the present review, we aimed to analyse the current state of disordered eating in Israel by means of an extensive literature review. The following are the main findings of our review: The frequency of maladaptive eating among female and male Israeli Jewish adolescents is higher in comparison to many other Westernised countries. Among different Jewish sub‐populations, Kibbutz women have been found until recently to show higher rates of disordered eating in comparison to other Israeli samples. Recent studies show no such difference between Kibbutz members and the general Israeli population. No clear‐cut findings emerge with respect to the influence of immigration and degree of Jewish religious affiliation on the occurrence of disordered eating. In contrast, disordered eating is less prevalent in Israeli‐Arabs compared with Israeli‐Jews. Moreover, diverse Israeli‐Arab groups show different rates of disordered eating. We discuss the high rate of disordered eating in Israeli youth in light of Israel being a culture in transition that is constantly exposed to the risk of terrorism. The changes in the rates of disordered eating in the Kibbutzim are discussed in light of the dramatic societal changes occurring in these communities within a relatively brief period of time. The low rates of disordered eating in Israeli‐Arabs reflect the traditional non‐Westernised characteristics of their society, whereas the differences between diverse Arab sub‐populations depend upon the degree of exposure to Westernised influences and the presence of conflicts between modern and traditional values. Copyright © 2008 John Wiley & Sons, Ltd and Eating Disorders Association.
Optimal power grid black start using fuzzy logic and expert system
Authors: Ye Wu , Xinyan Fang , Zheng Yan
Published: July 2008

Reasonable restoration plans for power systems after large‐scale power failures are important in both theory and practice. Based on fuzzy data envelopment analysis (DEA), an algorithm for assessing the black‐start schemes of power system is proposed in this paper. Depending on the concepts of L‐R fuzzy number and α‐cut, this algorithm drew important factors from the process of black start as fuzzy input or output indexes and then established a fuzzy computing model. After the black‐start schemes were sorted by the relative efficiency values of decision‐making units (DMUs), the best one was recommended to dispatchers. The instance of a real power system proves that it is a feasible method. Copyright © 2008 John Wiley & Sons, Ltd.
Vulnerability of interconnected power systems to malicious attacks under limited information
Authors: Bompard Ettore , Napoli Roberto , Xue Fei
Published: July 2008

Malicious attacks against critical infrastructures, and power systems as well, became a key‐concern in recent years. The attacks may be both “physical,” directed towards system components, and “cyber,” against the information/communication system; simultaneous attacks to different components, both physical and cyber, may be possible. In this context, the assessment of the vulnerability of a given interconnected power system, in terms of the possibility to keep it feasible after a defined attack, w.r.t a limited number of information available (both due to attacks or a regulatory rule) is of the utmost importance. In this paper, we propose a game model, based on the socially rational multi‐agent system (MAS) and fictitious play, which can be used to assess the sensitivity of the system structure and operational state to various availabilities of network information. From the model both a ranking of the critical information and a strategy of network reinforcement to decrease system vulnerability can be derived. The proposed model and methods are applied to a 34‐buses test system for illustrative purposes. Copyright © 2008 John Wiley & Sons, Ltd.
Analysis of the effects of Nyquist pulse‐shaping on the performance of OFDM systems with carrier frequency offset
Authors: Tan Peng , Beaulieu Norman C.
Published: July 2008

An exact method for calculating the bit error rate (BER) of an uncoded orthogonal frequency‐division multiplexing (OFDM) system with transmitter Nyquist pulse‐shaping over AWGN channels in the presence of frequency offset is derived. This method represents a unified way to calculate the BER of this system with different one‐ and two‐dimensional subcarrier modulation formats. The precise BER expressions are obtained using a characteristic function method.

The effects of several widely referenced Nyquist pulse‐shapings, including the Franks pulse, the raised‐cosine pulse, the ‘better than’ raised‐cosine (BTRC) pulse, the second‐order continuous window (SOCW), the double‐jump pulse and the polynomial pulse on intercarrier interference (ICI) reduction and BER improvement of the system with carrier frequency offset are examined in the AWGN channel. The dependence of the BER on the roll‐off factor of the pulse employed for a specific system in the presence of frequency offset is investigated. Analysis and numerical results show that the Franks pulse exhibits the best performance among the Nyquist pulses considered in most cases. Copyright © 2008 John Wiley & Sons, Ltd.