bluuebunny/crossref_metadata_2025 huggingface dataset:
Multijet electrospinning of conducting nanofibers from microfluidic manifolds
Authors: Srivastava Yasmin , Marquez Manuel , Thorsen Todd
Published: August 2007

We present a method for the electrospinning of conducting polymeric composite nanofibers using a poly(dimethyl siloxane) (PDMS)‐based microfluidic device. To scale‐up the process and spin multicomponent systems, we designed a unique multi‐spinnerette electrospinning device using microchannels cast in PDMS. Nanofibers of poly (vinylpyrrolidone) and its composite with polypyrrole were successfully prepared using one‐step and two‐step microfluidic electrospinning. The effect of processing variables on the morphology of the nanofibers formed using this devicewas also studied. SEM images showed that fiber diameter and morphology strongly depend on processing parameters such as concentration, applied electric field, feed rate, solvent, and ionic salt addition. FTIR spectroscopy and conductivity measurements reveal the polymerization of pyrrole in the matrix of poly(vinyl pyrrolidone). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Synthesis and characterization of soluble poly(amide‐imide)s bearing triethylamine sulfonate groups as gas dehumidification membrane material
Authors: Chen Guang , Zhang Xiaosa , Wang Junhua , Zhang Suobo
Published: August 2007

A series of soluble poly(amide‐imide)s (PAIs) bearing triethylammonium sulfonate groups were synthesized directly using trimellitic anhydride chloride (TMAC) polycondensation with sulfonated diamine such as 2,2′‐benzidinedisulfonic acid (BDSA), 4,4′‐diaminodiphenyl ether‐2,2′‐disulfonic acid (ODADS), and nonsulfonated diamine 4,4‐diaminodiphenyl methane in the presence of triethylamine. The resulting copolymers exhibited high molecular weights (high inherent viscosity), and a combination of desirable properties such as good solubility in dipolar aprotic solvents, film‐forming capability, and good mechanical properties. Wide‐angle X‐ray diffraction revealed that the polymers were amorphous. These copolymers showed high permeability coefficients of water vapor because of the presence of the hydrophilic triethylammonium sulfonate groups. The water vapor permeability coefficients (Pw) and permselectivity coefficients of water vapor to nitrogen and methane [α(H2O/N2) and α(H2O/CH4)] of the films increased with increasing the amount of the triethylammonium sulfonated groups. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Mass hatred in the Muslim and Arab world: the neglected problem of anti‐Semitism
Authors: Kressel Neil J.
Published: August 2007

In recent years, anti‐Jewish bigotry in the Muslim and Arab world has reached dangerous proportions, yet psychologists, sociologists, and other social scientists have produced scant research on the topic. This paper seeks to understand why there is so much hostility, paying particular attention to four potential sources: (1) Islamic history and theology, (2) frustration, anger and scapegoating, (3) socialization practices, and (4) the political context of the Arab‐Israeli conflict. Copyright © 2007 John Wiley & Sons, Ltd.
Review fluorescence correlation spectroscopy for probing the kinetics and mechanisms of DNA hairpin formation
Authors: Orden Alan Van , Jung Jaemyeong
Published: August 2007

This article reviews the application of fluorescence correlation spectroscopy (FCS) and related techniques to the study of nucleic acid hairpin conformational fluctuations in free aqueous solutions. Complimentary results obtained using laser‐induced temperature jump spectroscopy, single‐molecule fluorescence spectroscopy, optical trapping, and biophysical theory are also discussed. The studies cited reveal that DNA and RNA hairpin folding occurs by way of a complicated reaction mechanism involving long‐ and short‐lived reaction intermediates. Reactions occurring on the subnanoseconds to seconds time scale have been observed, pointing out the need for experimental techniques capable of probing a broad range of reaction times in the study of such complex, multistate reactions. © 2007 Wiley Periodicals, Inc. Biopolymers 89: 1–16, 2008.

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Differences in predictors of cervical and breast cancer screening by screening need in uninsured Latina women
Authors: P. Buki Lydia , Jamison Jorja , J. Anderson Carolyn , M. Cuadra Anai
Published: August 2007

BACKGROUND.

Latina women experience higher mortality for cervical cancer and lower 5‐year survival for breast cancer than non‐Latina White women. Adherence with screening recommendations can increase chances of survival, yet the factors that influence screening behaviors in uninsured women are not well documented.

METHODS.

Uninsured Latina women (N = 467) recruited in four US cities participated in the study. Logistic regression was used to model adherence to recommendations by screening type (cervical or breast cancer) and screening need (needs to obtain initial screening, overdue for rescreening, up‐to‐date with rescreening).

RESULTS.

Predictors differed by type of screening and screening need. Women who reported exposure to cancer education were more likely to have had a mammogram and to be up‐to‐date with Pap smear screening than women without such exposure. Women who were younger, had more than a sixth grade education, and/or had children were more likely to have had a Pap smear. Older women who had been in the US the longest were more likely to be overdue for a Pap smear. Women with incomes 5000 to 7000 were more likely to have obtained a mammogram. Regional differences were found with respect to mammography screening and maintenance behaviors.

CONCLUSIONS.

Exposure to cancer education is an important predictor of screenings among uninsured urban Latina women. The potential of creating educational interventions that can increase screening rates among women who evidence health disparities is encouraging. Recruitment strategies to reach women in need of screenings are provided. Cancer 2007. © 2007 American Cancer Society.
Prognostic factors for survival of stage I nonsmall cell lung cancer patients
Authors: Ou S.‐H. Ignatius , Zell Jason A. , Ziogas Argyrios , Anton‐Culver Hoda
Published: August 2007

BACKGROUND.

Platinum‐based adjuvant chemotherapy in randomized trials has failed to provide a survival benefit in patients with resected stage I nonsmall cell lung cancer (NSCLC). Using data from the California Cancer Registry (CCR), we explored factors that had detrimental effects on survival in patients with stage I NSCLC to identify a subset of patients at high risk for disease recurrence and subsequent mortality.

METHODS.

Between 1989 and 2003, 19,702 incident cases of stage I NSCLC in the CCR were identified and subgrouped into stage IA and IB disease. Patient demographic factors, tumor characteristics, and treatment delivered were examined. Kaplan‐Meier survival curves were calculated to estimate survival rates. Cox proportional‐hazards ratios were used to identify independent prognostic factors for survival.

RESULTS.

Advanced age at diagnosis, male sex, low socioeconomic status (SES), nonsurgical treatment, and poor histologic grade (stage IA NSCLC: hazards ratio [HR], 1.13; 95% confidence interval [95% CI], 1.08–1.19; stage IB NSCLC: HR, 1.11; 95% CI, 1.07–1.16) were associated with increased mortality risk on multivariate analysis. Nonupper lobe tumor location (right middle lobe, right and left lower lobes) and tumor size ≥4 cm (vs <4 cm: HR, 1.23; 95% CI, 1.15–1.30) were additional factors that increased the risk of mortality among patients with stage IB disease. Bronchioloalveolar carcinoma and Asian ethnicity were associated with decreased mortality risk in stage I NSCLC.

CONCLUSIONS.

Stage I NSCLC with poorly differentiated histology and stage IB NSCLC with nonupper lobar tumor location or tumor size ≥4 cm carried an increased mortality risk. Cancer 2007. © 2007 American Cancer Society.
Radical‐Enhanced Atomic Layer Deposition of Silver Thin Films Using Phosphine‐Adducted Silver Carboxylates
Authors: Niskanen A. , Hatanpää T. , Arstila K. , Leskelä M. , Ritala M.
Published: August 2007

Metallic silver films are deposited by radical‐enhanced atomic layer deposition (REALD) using (2,2‐dimethylpropionato)silver(I)triethylphosphine and hydrogen radicals. The silver precursor used is synthesized in‐house, and characterized using CHN elemental analysis, infrared (IR) spectroscopy, nuclear magnetic resonance (NMR), mass spectrometry (MS), and thermogravimetric analysis/single differential thermal analysis (TGA/SDTA). The crystal structure of Ag(O2CtBu)(PEt3) is also solved. Trimeric units are revealed as the building blocks. The hydrogen radicals are produced by dissociating molecular hydrogen with a microwave plasma discharge. The evaporation temperature of the silver precursor is 125 °C, and the film deposition temperature is 140 °C. The deposition is successful on glass and silicon, and the films are conformal. The saturated growth rate is 0.12 nm per cycle, with a 3 s silver precursor pulse and 5 s hydrogen radical pulse time. The overall cycle time is 14 s. The films are polycrystalline and are visually mirror‐like. The films contain 10 at.‐% oxygen, 4.0 at.‐% phosphorous, 1.0 at.‐% carbon, and 5.0 at.‐% hydrogen as impurities. Nevertheless, the films exhibit low resistivity, only 6 μΩ cm for a 40 nm thick film.
Study of Magnesium Boride Films Obtained From Mg(BH4)2 by CVD
Authors: Crociani L. , Rossetto G. , Kaciulis S. , Mezzi A. , El‐Habra N. , Palmieri V.
Published: August 2007

Magnesium boride films are synthesized from Mg(BH4)2 by CVD. A new synthesis of the precursor is developed. Deposition time of the samples is varied to study its influence on film composition. The films are analyzed by means of X‐ray diffraction (XRD) and X‐ray photoelectron spectroscopy (XPS). The contributions of various chemical species (boride and oxides) in the depth profiles, carried out using Ar ion sputtering combined with cyclic XPS measurements, are separated by peak‐fitting analysis of photoelectron B1s and Auger MgKLL spectra. The samples are composed of MgBx film covered by an overlayer of magnesium and boron oxides.
Synthesis and Structures of Bis(2‐dimethylaminoethyl)amine Adducts of Strontium Bis(2,2,6,6‐tetramethylheptane‐3,5‐dionate) and Their Use in the CVD of Cubic Strontium‐Doped Hafnium Dioxides
Authors: Luo B. , Yu D. , Kucera B. E. , Campbell S. A. , Gladfelter W. L.
Published: August 2007

Monomeric, eight‐coordinate Sr(tmhd)2[HN(CH2CH2NMe2)2](EtOH) (1), where tmhd is 2,2,6,6‐tetramethylheptane‐3,5‐dionato, is synthesized from the reactions of HN(CH2CH2NMe2)2, H‐tmhd, and Sr(OEt)2(EtOH)4. Heating compound 1 at 130 °C dissociates EtOH to form monomeric, seven‐coordinate Sr(tmhd)2[HN(CH2CH2NMe2)2] (2). A combination of thermogravimetric analysis (TGA) and thermal stability tests establishes that compound 2 is stable at temperatures below 220 °C. In a cold‐wall, low‐pressure CVD reactor, 2 is used as a liquid precursor at 115 to 175 °C to deposit high‐κ, dielectric, strontium hafnium oxide films in combination with the use of Hf(OtBu)4. The Sr/(Sr + Hf) atomic ratios of the films range from 0 to 0.83. X‐ray diffraction (XRD) shows that films with low Sr doping, e.g., ≤ 0.15, exhibit a crystalline phase consistent with Sr‐stabilized cubic hafnia, while films with higher Sr contents are amorphous. The dielectric constants of the films increase as the proportion of the cubic phase increases. A maximum value of 25 is obtained for the film with a Sr/(Sr + Hf) ratio of 0.07.
Minimizing the Carbon Content of Thin Ruthenium Films by MOCVD Precursor Complex Design and Process Control
Authors: Schneider A. , Popovska N. , Jipa I. , Atakan B. , Siddiqi M. A. , Siddiqui R. , Zenneck U.
Published: August 2007

[(Benzene)(1,3‐cyclohexadiene)Ru] was investigated as a designed metal‐organic (MO) CVD precursor where the inherent structural and chemical features of the ligands help the formation of pure ruthenium films. The investigations have been performed with Si wafers as the substrate at a total gas pressure of 50 mbar, substrate temperature range of 200–450 °C, and helium carrier gas velocity of 1.5 to 16.5 cm s–1. The main focus was on the evaluation of the process parameters that promote the purity of the deposited ruthenium films without the help of a reactive gas component. The composition of the MOCVD exhaust gas was analyzed by gas chromatography (GC), and the deposited ruthenium films characterized by elastic recoil detection analyses (ERDA) to relate the carbon content of the films with the follow‐up chemistry of the ligands. The primary process of highly effective dehydrogenation of the 1,3‐cyclohexadiene ligand at the freshly formed ruthenium surface to form benzene was built in by the choice of the ligand. Further, but much less effective, was the dehydrogenation of benzene, which is presumed to be the main process for carbon contamination. Ruthenium films with only 3 mol.‐% carbon content were deposited at a substrate temperature of 300 °C and a carrier gas velocity of 12.8 cm s–1. In all cases the deposited films consist of polycrystalline metallic ruthenium with a low surface roughness.
Alcohol‐Assisted CVD of Silver Using Commercially Available Precursors
Authors: Bahlawane N. , Premkumar P. A. , Brechling A. , Reiss G. , Kohse‐Höinghaus K.
Published: August 2007

A novel chemical approach was demonstrated for the growth of high‐quality, silver films by CVD. This concept relies on the catalytic reactivity of cationic silver, and of silver surfaces with alcohols. This leads to high‐purity films using either state‐of‐the‐art precursors or silver salts that have not been yet considered as CVD precursors. The occurrence of the catalytic oxidative‐dehydrogenation of alcohols, considered as the driving force in this process, was shown by in‐situ mass spectrometry (MS). Films of fcc‐Ag with ρ ≤ 2 μΩ cm were grown without any noticeable contamination. Ag(hfac)COD leads to the growth of a (111) highly orientated film on glass at a rate of 1.66 nm min–1, while polycrystalline films are grown at a rate of 18.5 nm min–1 using AgNO3.
Obituary: Professor Liliane G. Hubert‐Pfalzgraf
Authors: Jones A. C.
Published: August 2007

Professor Liliane G. Hubert‐Pfalzgraf (1947–2006) is remembered by her French colleagues and the Associate Scientific Editor of Chemical Vapor Deposition, Tony Jones.
Sicherheitsbeurteilung historischer Steinbogenbrücken
Authors: Proske Dirk , Lieberwirth Peter , van Gelder Pieter H.A.J.M.
Published: August 2007

Der Artikel gibt einen Überblick über die Anwendung moderner Sicherheitskonzepte zur Untersuchung der Tragfähigkeit historischer Steinbogenbrücken. Dabei zeigt sich, dass trotz häufig vorgebrachter Kritik gegenüber modernen Sicherheitskonzepten diese auch Anpassungen erlauben, die gerade bei historischen Bauwerken interessant werden können. Neben der sich daraus ergebenden Änderung der Sicherheitselemente, z. B. der Teilsicherheitsfaktoren, besteht darüber hinaus auch die Möglichkeit, die Einwirkungen anzupassen. Somit ergibt sich für den Statiker nicht nur die Möglichkeit der Variation der mechanischen Nachweismodelle, sondern auch die Möglichkeit der Anpassung der Sicherheitselemente an die spezifischen Fragestellungen historischer Steinbogenbrücken.
Severinstorburg und U‐Bahnbau – Sicherung eines der Symbole der Domstadt
Authors: Tebbe Holger , Dominik Axel , Brauer Norbert
Published: August 2007

Die im Severinsviertel gelegene Severinstorburg ist einer der herausragenden Identifikationspunkte der Stadt Köln. Der Ort weist eine bemerkenswerte Siedlungskontinuität auf. Das in Ausfallrichtung Bonn orientierte, mittelalterliche Stadttor liegt exakt auf der Trasse der ehemaligen römischen Reichsstraße von Köln nach Bonn. Das Tor markiert so u. a. eine 2000‐jährige Verkehrsgeschichte. Der nun im Abschluss befindliche U‐Bahnbau reiht sich somit übergangslos in diese Tradition ein. Im folgenden Artikel soll über die Besonderheiten der Sicherung bei der Unterfahrung der denkmalgeschützten Bausubstanz berichtet werden.
Neue Zentrier‐ und Trennlage zur Auflagerung von Stahlbetondecken auf Wänden aus Mauerwerk
Authors: Jäger Wolfram , Sabha Ahmad
Published: August 2007

Von der Ausbildung und Ausführung des Wand‐Decken‐Knotens hängen das Trag‐ und Verformungsverhalten sowie die Rissempfindlichkeit von Konstruktionen aus Mauerwerkswänden und Stahlbetondecken ab. In der Praxis ist die Einlage einer Bitumenbahn zwischen Stahlbetondecken und Mauerwerkswänden üblich, um dem unterschiedlichen Verformungsverhalten von Stahlbetondecke und Wand Rechnung zu tragen. Im vorliegenden Beitrag wird eine Alternativlösung vorgeschlagen, die neben der Möglichkeit des Abfangens der Schwindverformungen der Decke noch eine Lastzentrierung und damit eine bessere Mauerwerksauslastung ermöglicht. Sie besteht aus einem Glasfasergitter, darauf befestigten kompressiblen Streifen im Randbereich und der auf der Baustelle aufzubringenden Mörtelschicht normaler Dicke. Die Lösung wird mit der Bitumenpappe verglichen und ihre Gleich‐ bzw. Höherwertigkeit herausgearbeitet.
DGfM: Mauerwerk 4/2007
Authors: Rast Ronald
Published: August 2007

Energieausweis jetzt auf den Weg bringen

Bundesregierung ebnet den Weg zur Einführung von Energieausweisen für Gebäude

BFW‐Studie: zu wenig Seniorenimmobilien

DGfM‐Newsletter: Bereich Markt; Bereich Technik; Aktuell; Termine.
Carbohydrate Chemistry in the Total Synthesis of Saponins
Authors: Yu Biao , Zhang Yichun , Tang Pingping
Published: August 2007

Significant examples relating to the total synthesis of natural saponins with potent biological activities are discussed, with major emphasis on the applicability of contemporary glycosylation and protecting group manipulation protocols to the sophisticated scaffolds of steroids/triterpenes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Evaluation of different warping methods for the analysis of CE profiles of urinary nucleosides
Authors: Szymańska Ewa , Markuszewski Michał Jan , Capron Xavier , van Nederkassel Anne‐Marie , Vander Heyden Yvan , Markuszewski Marcin , Krajka Kazimierz , Kaliszan Roman
Published: August 2007

Nowadays, numerous metabolite concentrations can readily be determined in a given biological sample by high‐throughput analytical methods. However, such raw analytical data comprise noninformative components due to many disturbances normally occurring in the analyses of biological material. To eliminate those unwanted original analytical data components, advanced chemometric data preprocessing methods might be of help. Here, such methods are applied to electrophoretic nucleoside profiles in urine samples of cancer patients and healthy volunteers. In this study, three warping methods: dynamic time warping (DTW), correlation optimized warping (COW), and parametric time warping (PTW) were examined on two sets of electrophoretic data by means of quality of peaks alignment, time of preprocessing, and way of customization. The application of warping methods helped to limit shifting of peaks and enabled differentiation between whole electropherograms of healthy and cancer patients objectively by a principal component analysis (PCA). The evaluation of preprocessed data and raw data by PC analysis confirms differences between the applied warping tools and proves their suitability in metabonomic data interpretation.
Fast quantitative determination of diuretic drugs in tablets and human urine by microchip electrophoresis with native fluorescence detection
Authors: Tolba Kamal , Belder Detlev
Published: August 2007

Microchip electrophoresis (MCE) with native fluorescence detection has been applied for the fast quantitative analysis of pharmaceutical formulations. For this purpose, methods for fast separation and sensitive detection of the unlabeled diuretic drugs, amiloride, triamterene, bendroflumethiazide (BFMTZ), and bumetanide were developed. An epifluorescence setup was used enabling the coupling of different lasers into a commercial fluorescence microscope. The detection sensitivity of different excitation light sources was compared utilizing either a HeCd laser (λexc = 325 nm), a frequency quadrupled Nd:YAG laser (λexc = 266 nm), or a mercury lamp (λexc = 330–380 nm). At optimal conditions using the HeCd laser, the drugs were separated within 15 s with LODs less than 1 μg/mL for the four compounds. A linear relationship between concentration and peak area was obtained in the concentration range of 0.05–20 μg/mL with a mean correlation coefficient of around 0.996 for all analytes. The method was successfully applied to the analysis of the respective drugs in commercial formulations and in human urine without interference from other constituents. These data show that MCE has a great potential for reliable drug analysis.
Determination of tetracycline residues in honey by CZE with ultraviolet absorbance detection
Authors: Casado‐Terrones Silvia , Segura‐Carretero Antonio , Busi Simone , Dinelli Giovanni , Fernández‐Gutiérrez Alberto
Published: August 2007

We have developed a sensitive CE method to determine eight tetracyclines (TCs) (chlortetracycline, demeclocycline, doxycycline, methacycline, minocycline, oxytetracycline, TC, and rolitetracycline (RTC)) in honey samples. The running buffer was 150 mM sodium borate (pH 9.8) and 2.5% 2‐propanol with 15 s hydrodynamic injection at 25 kV. We have also developed an SPE procedure with a C18 cartridge as a clean‐up step. Analytes were detected at 360 nm in less than 16 min. LODs ranged in honey from 23.9 μg/kg for TC to 49.3 μg/kg for RTC. Seven samples of Spanish honey of different floral origins were examined. None of them showed contamination with these antibiotics using the proposed method.
Modeling ssDNA electrophoretic migration with band broadening in an entangled or cross‐linked network
Authors: Chen Zheng , Graham Richard , Burns Mark A. , Larson Ronald G.
Published: August 2007

We use a coarse‐grained model proposed by Graham and Larson based on the temporary network model by Schieber et al.. [1] to simulate the electrophoretic motion of ssDNA and corresponding band broadening due to dispersion. With dimensionless numbers reflecting the experimental physical properties, we are able to simulate ssDNA behavior under weak to moderate electric field strengths for chains with 8–50 entanglements per chain (∼1000–8500 base pairs), and model smoothly the transition from reptation to oriented reptation. These results are fitted with an interpolation equation, which allows the user to calculate dimensionless mobilities easily from input parameters characterizing the gel matrix, DNA molecules, and field strengths. Dimensionless peak widths are predicted from mobility fluctuations using the central limit theorem and the assumption that the mobility fluctuations are Gaussian. Using results from previous studies of ssDNA physical properties (effective charge ξq and Kuhn step length bK) and sieving matrix properties (pore size or tube diameter a), we give scaling factors to convert the dimensionless values to “real” experimental values, including the mobility, migration distance, and time. We find that the interpolation equation fits well the experimental data of ssDNA mobilities and peak widths, supporting the validity of the coarse‐grained model. The model does not account for constraint release and hernia formation, and assumes that the sieving network is a homogeneous microstructure with no temperature gradients and no peak width due to injection. These assumptions can be relaxed in future work for more accurate prediction.
Specific and genotypic identification of Cryptosporidium from a broad range of host species by nonisotopic SSCP analysis of nuclear ribosomal DNA
Authors: Jex Aaron R. , Ryan Una M. , Ng Josephine , Campbell Bronwyn E. , Xiao Lihua , Stevens Melita , Gasser Robin B.
Published: August 2007

The accurate identification of Cryptosporidium (Protozoa: Apicomplexa) species and genotypes is central to the understanding of the transmission and to the diagnosis and control of cryptosporidiosis. In this study, we demonstrate the effectiveness of nonisotopic SSCP analysis of a ∼300 bp region of the small subunit (pSSU) of ribosomal DNA for the specific identification of and delineation among 18 different Cryptosporidium species and genotypes from a wide range of hosts. This mutation scanning approach allowed the rapid and reliable differentiation between species/genotypes differing by as little as 1.3% in the pSSU sequence, with the capacity to detect point mutations. The present findings confirm the usefulness of this tool for the rapid genetic screening of Cryptosporidium samples from any host species, providing a foundation for detailed systematic, epidemiological and ecological studies. Although applied herein to pSSU, this low cost approach should be applicable to a wide range of genetic loci for population genetic investigations of Cryptosporidium.
Low EOF rate measurement based on constant effective mobility in microchip CE
Authors: Wang Wei , Zhao Liang , Zhou Fang , Zhang Jian‐Rong , Zhu Jun‐Jie , Chen Hong‐Yuan
Published: August 2007

A new method for quickly determining low EOF rates (μEOF) in microchip CE is described. The measurement is based on the notion that the effective mobility (μeff) of an analyte is a constant in a certain BGE. The μeff of an analyte is determined in a reference fast‐electroosmosis microchip, and the apparent mobility (μapp) of the analyte can be determined in the microchip with unknown low electroosmosis, and then μEOF in the low‐electroosmosis microchip can be calculated according to the equation μEOF = μapp − μeff. By an indirect method or other conventional methods, μeff can be easily measured in the reference microchip. The proposed method is particularly useful for low‐electroosmosis measurements in wall‐modified microchannels.
Fabrication of poly(methyl methacrylate) microfluidic chips by redox‐initiated polymerization
Authors: Chen Jiang , Lin Yuehe , Chen Gang
Published: August 2007

In this report, a method based on the redox‐initiated polymerization of methyl methacrylate (MMA) has been developed for the rapid fabrication of poly(methyl methacrylate) (PMMA) microfluidic chips. MMA containing 2‐2′‐azo‐bis‐isobutyronitrile was allowed to prepolymerize in a water bath to form a viscous prepolymer solution that was subsequently mixed with MMA containing a redox‐initiation couple of benzoyl peroxide/N,N‐dimethylaniline. The dense molding solution was sandwiched between a silicon template and a piece of 1‐mm‐thick PMMA plate. The polymerization could complete within 50 min under ambient temperature. The images of raised microfluidic structures on the silicon template were precisely replicated into the synthesized PMMA substrate during the redox‐initiated polymerization of the molding solution. The chips were subsequently assembled by the thermal bonding of the channel plates and the covers. The new fabrication approach obviates the need for special equipment and significantly simplifies the process of fabricating PMMA microdevices. The attractive performance of the novel PMMA microchips has been demonstrated in connection with contactless conductivity detection for the separation and detection of ionic species.
Improvement of transient stability by unified power flow controller based on Hamiltonian system theory
Authors: Hao J. , Shi Li‐Bao , Ni Yi‐Xin , Chen C.
Published: August 2007

In this paper we propose a novel Hamiltonian theory based controller design methodology for unified power flow controller (UPFC) control to improve the dynamic performance of power systems. The Hamiltonian theory of the differential‐algebraic (DA) system is described and a simple control strategy is deduced to stabilize the system. Furthermore, the influence of the control law on the stability region of the system is discussed as well. It can be proved that the stability region of the system can indeed be enlarged under the control strategy. The UPFC control scheme of multi‐machine power system is developed, and a classical three‐generator system is used to validate the effectiveness of the control law. Copyright © 2007 John Wiley & Sons, Ltd.
On estimating an asset's implicit beta
Authors: Husmann Sven , Stephan Andreas
Published: August 2007

A.F. Siegel (1995) has developed a technique with which the systematic risk of a security (beta) can be estimated without recourse to historical capital market data. Instead, beta is estimated implicity from the current market prices of exchange options that enable the exchange of a security against shares on the market index. Because this type of exchange options is not currently traded on the capital markets, Siegel's technique cannot yet be used in practice. This study will show that beta can also be estimated implicitly from the current market prices of plain vanilla options, based on the capital asset pricing model. Empirical evidence on implicit betas is provided using prices of exchange options from the European Derivatives Exchange Market (EUREX) over years 2000 to 2004. © 2007 Wiley Periodicals, Inc. Jrl Fut Mark 27:961–979, 2007
Short/long heterozygotes at 5HTTLPR and white matter lesions in geriatric depression
Authors: Steffens David C. , Taylor Warren D. , McQuoid Douglas R. , Krishnan K. Ranga R.
Published: August 2007

Objective

We examined the relationship between 5HTTLPR genotype and volume of magnetic resonance imaging (MRI) brain lesions.

Method

We studied 217 older depressed patients and 141 individuals in the comparison group using a standard brain MRI protocol to calculate lesion volumes. Genotype at 5HTTLPR was determined for each subject.

Results

In age‐adjusted models, the l/s genotype was associated with increased volume of total and white‐matter lesions among depressed patients. This relationship lost significance in models controlling for reported hypertension.

Conclusions

The finding that 5HTTLPR heterozygotes have higher vascular lesion volumes may be related to development of hypertension. Copyright © 2007 John Wiley & Sons, Ltd.
Diagnosing dementia ‐ ICD‐10 not so bad after all: a comparison between dementia criteria according to DSM‐IV and ICD‐10
Authors: Naik Mala , Nygaard Harald A.
Published: August 2007

Background

The discrepancy between results of diagnosing dementia with ICD‐10 and DSM‐IV has been shown by several studies. Our aim was to show that the two diagnostic systems are more or less alike if ICD‐10 is interpreted in the way we believe is in the intention of the ICD‐10 authors.

Methods

Two hundred and seven patients consecutively referred patients and their caregivers were interviewed and the patients were clinically examined. Algorithms using criteria for the World health Organization's International classification of Diseases, 10th revision (ICD‐10) and the American Psychiatric Association's, the fourth edition (DSM‐IV) were followed to diagnose dementia.

Results

A diagnosis of dementia was made for 198 patients and there was 100% agreement (kappa = 1,0) between ICD‐10 and DSM‐IV diagnosis.

Conclusion

In the ICD‐10 criteria ‘decline in other cognitive abilities such as abstraction, judgement, problem solving’ has been interpreted in a way that all the above executive functions must be impaired for diagnosing dementia. According to our interpretation these are meant to be examples of functions which may be compromised in demented patients.

The results of our study demonstrate that this interpretation of ICD‐10 has shown that the authors of ICD‐10 and DSM‐IV have succeeded in harmonising the two systems. However, the ICD‐10 criteria are phrased in a way that leaves much to individual interpretation. WHO has to define the ICD criteria in such a way that there is uniformity in its interpretation. Copyright © 2007 John Wiley & Sons, Ltd.
Calcium‐independent phospholipase A2 influences AMPA‐mediated toxicity of hippocampal slices by regulating the GluR1 subunit in synaptic membranes
Authors: Ménard Caroline , Chartier Émilie , Patenaude Christian , Robinson Pierre , Cyr Michel , Baudry Michel , Massicotte Guy
Published: August 2007

We have recently documented that phosphorylation of the GluR1 subunit of α‐amino‐3‐hydroxy‐5‐methylisoxazole‐propionate (AMPA) glutamate receptors is influenced by calcium‐independent forms of phospholipase A2 (iPLA2) activity in the brain. Given the importance of GluR1 subunit phosphorylation in the control of AMPA receptor delivery to synaptic membranes, we tested the influence of iPLA2 activity on AMPA receptor distribution between neuronal compartments, using organotypic cultured hippocampal slices. In agreement with earlier reports, the iPLA2 inhibitor bromoenol lactone (BEL) markedly enhanced the phosphorylation of the GluR1 subunit at both Ser831 and Ser845 residues. GluR1 subunit phosphorylation levels were selectively increased by (R)‐BEL, an enantio‐selective inhibitor of iPLA2γ, but not by (S)‐BEL, an iPLA2β inhibitor. The iPLA2γ inhibitor R‐BEL also promoted the insertion of new GluR1 subunits into synaptic membranes and exacerbated AMPA‐mediated cell death in the CA1 region of the hippocampus. The latter effect was selectively abolished by IEM 1460 and philanthotoxin‐433, two antagonists specific for AMPA receptors lacking GluR2 subunits. These results provide evidence that iPLA2γ‐related regulation of AMPA receptor GluR1 subunit phosphorylation could represent an important mechanism modulating hippocampal cell death induced by AMPA receptor overstimulation. © 2007 Wiley‐Liss, Inc.
Evidence for episodic memory in a pavlovian conditioning procedure in rats
Authors: O'Brien Jamus , Sutherland Robert J.
Published: August 2007

In an effort to evaluate episodic memory processes in the rat, we developed a novel Pavlovian conditioning procedure. Rats explored two distinctive contexts, one in the morning and the other in the evening. Subsequently, either in the morning or the evening, they received a foot shock immediately upon entry into a third context that equally resembled the two explored contexts. When conditioned freezing was measured at an intermediate time of day, rats showed significantly more fear of the context congruent with the time of day of the foot shock. Thus, rats automatically form an integrated time–place memory that can be flexibly updated by future events, essential characteristics of episodic memory. © 2007 Wiley‐Liss, Inc.
Perirhinal and hippocampal contributions to visual recognition memory can be distinguished from those of occipito‐temporal structures based on conscious awareness of prior occurrence
Authors: Danckert S.L. , Gati J.S. , Menon R.S. , Köhler S.
Published: August 2007

The ability of humans to distinguish consciously between new and previously encountered objects can be probed with visual recognition memory tasks that require explicit old–new discriminations. Medial temporal‐lobe (MTL) lesions impair performance on such tasks. Within the MTL, both perirhinal cortex and the hippocampus have been implicated. Cognitive processes can also be affected by past object encounters in the absence of conscious recognition, as in repetition priming tasks. Past functional neuroimaging findings in healthy individuals suggest that even in tasks that require conscious recognition decisions for visual stimuli, posterior cortical structures in the ventral visual pathway distinguish between old and new objects at a nonconscious level. Conclusive evidence that differentiates the neural underpinnings of conscious from nonconscious processes in recognition memory, however, is still missing. In particular, functional magnetic resonance imaging (fMRI) findings for the MTL have been inconsistent towards this end. In the present fMRI study, we tested whether perirhinal and hippocampal contributions to recognition memory can be distinguished from those of occipito‐temporal structures in the ventral visual pathway based on the participants' reported conscious awareness of prior occurrence. Images of objects with a large degree of feature overlap served as stimuli; they were selected to ensure an involvement of perirhinal cortex in the present recognition task, based on evidence from past lesion‐based research. We found that both perirhinal cortex and occipito‐temporal cortex showed a differential old–new response that reflected a repetition‐related decrease in activity (i.e., new > old). Whereas in perirhinal cortex this decrease was observed with respect to whether subjects reported objects to be old or new, irrespective of the true item status, in occipito‐temporal cortex it occurred in relation to whether objects were truly old or new, irrespective of the participants' conscious reports. Hippocampal responses differed in their exact pattern from those of perirhinal cortex, but were also related to the conscious recognition reports. These results indicate that both perirhinal and hippocampal contributions can be distinguished from those of occipito‐temporal structures in the ventral visual pathway based on the participants' reported conscious awareness of prior occurrence. © 2007 Wiley‐Liss, Inc.
The hippocampal indexing theory and episodic memory: Updating the index
Authors: Teyler Timothy J. , Rudy Jerry W.
Published: August 2007

A little over 20 years ago, (Teyler and DiScenna,1986; Behav Neurosci 100:147–152) proposed the hippocampal memory index theory. It offered an account of episodic memory based on the intrinsic organization of the hippocampus, its synaptic physiology and its anatomical relationship to other regions of the brain. The essence of their idea was that the hippocampus was functionally designed and anatomically situated to capture information about neocortical activity generated by the individual features of behavioral episode. Moreover, because the hippocampus projects back to these neocortical regions the information it stored could serve as an index to the pattern of neocortical activity produced by the episode. Consequently, a partial cue that activated the index could activate the neocortical patterns and thus retrieve the memory of the episode. In this article we revisit and update indexing theory. Our conclusion is that it has aged very well. Its core ideas can be seen in many contemporary theories and there is a wealth of data that support this conceptual framework. © 2007 Wiley‐Liss, Inc.
Dysregulation of growth factor receptor‐bound protein 2 and fascin in hippocampus of mice polytransgenic for chromosome 21 structures
Authors: Shin Joo‐Ho , Guedj Fayçal , Delabar Jean‐Maurice , Lubec Gert
Published: August 2007

Nonchimeric polytransgenic 152F7 mice encompassing four human chromosome 21 genes (DSCR3, DSCR5, TTC3, and DYRK1A) within the Down syndrome critical region present with learning and memory impairment. However, no abnormalities were shown by in vitro electrophysiological or neuroanatomical findings in hippocampus of 152F7 mice. To search for molecular changes that may be linked to cognitive impairment, we compared hippocampal protein levels between nontransgenic (WT) and 152F7 mice by a proteomic approach. Protein extracts were run on two‐dimensional gel electrophoresis, protein spots were analyzed by mass spectrometry (MALDI‐TOF‐TOF) followed by quantification by specific software. Three hundred and nineteen different gene products were identified, and 48 proteins were assigned as signaling‐related proteins. Stringent statistical analysis considering P < 0.005 as statistically significant based upon multiple testing revealed that growth factor receptor‐bound protein 2 (Grb2) levels were decreased and an expression form of fascin 1 was increased in 152F7 mice when compared with WT. A series of proteins showed trends for increased and decreased hippocampal levels (P > 0.005 and P < 0.05). Only 2 out of 319 different gene products were dysregulated, pointing to the specificity of the analysis. Decreased Grb2 levels in the hippocampus of 152F7 mice may contribute to impaired cytoskeleton functions because dynamin 1 binds to Grb2 and involved in the formation of the endocytic process. Fascin dysregulation is of relevance for actin bundling in vesicle trafficking and may represent or lead to impaired neurotransmission that, in turn, may lead to the cognitive defect observed in this mouse model of Down syndrome. © 2007 Wiley‐Liss, Inc.
Differential involvement of the dorsal hippocampus in passive avoidance in C57bl/6J and DBA/2J mice
Authors: Baarendse Petra J.J. , van Grootheest Gerard , Jansen René F. , Pieneman Anton W. , Ögren Sven Ove , Verhage Matthijs , Stiedl Oliver
Published: August 2007

The inferior performance of DBA/2 mice when compared to C57BL/6 mice in hippocampus‐dependent behavioral tasks including contextual fear conditioning has been attributed to impaired hippocampal function. However, DBA/2J mice have been reported to perform similarly or even better than C57BL/6J mice in the passive avoidance (PA) task that most likely also depends on hippocampal function. The apparent discrepancy in PA versus fear conditioning performance in these two strains of mice was investigated using an automated PA system. The aim was to determine whether these two mouse strains utilize different strategies involving a different contribution of hippocampal mechanisms to encode PA. C57BL/6J mice exhibited significantly longer retention latencies than DBA/2J mice when tested 24 h after training irrespective of the circadian cycle. Dorsohippocampal NMDA receptor inhibition by local injection of the selective antagonist DL‐2‐amino‐5‐phosphonovaleric acid (AP5, 3.2 μg/mouse) before training resulted in impaired PA retention in C57BL/6J but not in DBA/2J mice. Furthermore, nonreinforced pre‐exposure to the PA system before training caused a latent inhibition‐like reduction of retention latencies in C57BL/6J, whereas it improved PA retention in DBA/2J mice. These pre‐exposure experiments facilitated the discrimination of hippocampal involvement without local pharmacological intervention. The results indicate differences in PA learning between these two strains based on a different NMDA receptor involvement in the dorsal hippocampus in this emotional learning task. We hypothesize that mouse strains can differ in their PA learning performance based on their relative ability to form associations on the basis of unisensory versus multisensory contextual/spatial cues that involve hippocampal processing. © 2007 Wiley‐Liss, Inc.
Estradiol enhances long term potentiation in hippocampal slices from aged apoE4‐TR mice
Authors: Yun Sung Hwan , Park Kyung A. , Kwon Sung , Woolley Catherine S. , Sullivan Patrick M. , Pasternak Joseph F. , Trommer Barbara L.
Published: August 2007

Hormone replacement therapy to treat or prevent Alzheimer Disease (AD) in postmenopausal women is controversial because it may pose other health risks such as cancer and thromboembolism. ApoE status is thought to influence the nootropic efficacy of hormone therapy, but findings are neither consistent nor well understood. We used a known in vitro memory model (long‐term potentiation, LTP) in aged (24–27 month) female targeted replacement mice expressing human apoE3 or E4 to compare the effects of exogenous estradiol. Recording medial perforant path evoked field potentials in dentate gyrus of hippocampal slices, we found that both strains exhibited comparable basal synaptic transmission as assessed by input/output functions and paired pulse depression, and that these measures were not affected by estradiol. Vehicle‐treated groups from both strains showed comparable LTP. Estradiol had no effect on LTP in apoE3‐TR, but selectively increased LTP magnitude in apoE4‐TR. The estradiol induced enhancement of LTP in aged female apoE4‐TR is consistent with recent clinical observations that estrogen replacement decreases AD risk in some women with apoE4. Elucidating the mechanism of this selective enhancement may lead to more informed treatment decisions as well as to the development of safer alternatives to hormone therapy. © 2007 Wiley‐Liss, Inc.
Adhesion of Streptococcus sanguinis to glass surfaces measured by isothermal microcalorimetry (IMC)
Authors: Hauser‐Gerspach Irmgard , de Freitas Patricia Scandiucci , Dan Daniels A.U. , Meyer Jürg
Published: August 2007

Bacterial adhesion is the first step in the development of the oral biofilm, called dental plaque. Plaque is the cause of caries, periodontal diseases, and periimplantitis. Investigations of dental plaque, including bacterial adhesion, employ various in vivo and invitro models using microscopic methods. Microcalorimetry offers another direct approach. The model organism Streptococcus sanguinis is one of the first colonizers adhering to the saliva‐coated human tooth surfaces or dental materials within minutes after tooth cleaning. TAM III™ thermostats, equipped with microcalorimeters, were used for isothermal microcalorimetric (IMC) measurements of heat production as a function of time, expressed by power–time (p–t) curves. Continuous measurements of heat production of growing S. sanguinis cells showed their overall metabolic activity and were highly reproducible. For the adhesion experiments the bacteria were allowed to adhere to different amounts of glass beads. Growing S. sanguinis cells produced a characteristic p–t curve with a maximum of 500 μW at 4.5 h when reaching 109 cells ml−1. The same number of stationary S. sanguinis cells, suspended in PBS produced only ∼30 μW at 0.5 h due to adhesion. But the amount of heat increased with available glass surface area, indicating that a portion of the heat of adhesion was measured. Similar results were obtained with stationary S. sanguinis cells suspended in human saliva. This study shows that microcalorimetric evaluation of initial bacterial adhesion is indeed possible and may become a rapid, reproducible screening method to study adhesion of different bacteria to different dental materials or to modified surfaces. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008
Finite element analysis of subsurface damage of ceramic prostheses in simulated intraoral dental resurfacing
Authors: Song Xiao‐Fei , Yin Ling , Han Yi‐Gang , Li Jia
Published: August 2007

Finite element analysis (FEA) was used to investigate the stress fields and the degrees of subsurface damage of ceramic prostheses in simulated intraoral dental resurfacing operations using clinical diamond burs. A two‐dimensional finite element model was established with the dental operational parameters and the material properties as input variables. This model enabled to predict the stress fields and to evaluate the depths of subsurface damage in ceramic prostheses as functions of the dental resurfacing operational conditions. The results indicate that the tensile, shear, compressive, and equivalent von Mises stresses were all centered under the diamond bur–specimen contact zone. The maximum values of these stresses were concentrated at the diamond grit exit point, decreasing with an increase in depth of cut. The predicted depths of subsurface damage increased with an increase in both the depth of cut and the maximum chip thickness, in the range of 30–140 μm. Also, the depths of subsurface damage were experimentally measured using scanning electron microscopy (SEM). The FEA predictions were found to be in agreement with the SEM experimental observations. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008