bluuebunny/crossref_metadata_2025 huggingface dataset:
Aminoacyl-tRNA synthetase complexes: beyond translation
Authors: Lee Sang Won , Cho Byeong Hoon , Park Sang Gyu , Kim Sunghoon
Published: July 2004

Although aminoacyl-tRNA synthetases (ARSs) are housekeeping enzymes essential for protein synthesis, they can play non-catalytic roles in diverse biological processes. Some ARSs are capable of forming complexes with each other and additional proteins. This characteristic is most pronounced in mammals, which produce a macromolecular complex comprising nine different ARSs and three additional factors: p43, p38 and p18. We have been aware of the existence of this complex for a long time, but its structure and function have not been well understood. The only apparent distinction between the complex-forming ARSs and those that do not form complexes is their ability to interact with the three non-enzymatic factors. These factors are required not only for the catalytic activity and stability of the associated ARSs, such as isoleucyl-, methionyl-, and arginyl-tRNA synthetase, but also for diverse signal transduction pathways. They may thus have joined the ARS community to coordinate protein synthesis with other biological processes.
Noise exposure in orthopaedic practice: potential health risk
Authors: Ullah Ramzan , Bailie Neil , Crowther Sean , Cullen James
Published: July 2004

Noise exposure is one of the major causes of permanent hearing loss in society. Exposure of health service staff to intense levels of noise in the workplace is a potential risk for the development of temporary and permanent hearing loss.

In this prospective study, 18 members of the orthopaedic staff underwent hearing assessment by pure tone audiometry and speech discrimination prior to noise exposure at the workplace and immediately following cessation of work. The number of hours of exposure and noise levels in the workplace was also analysed.

Only minimal temporary sensorineural threshold shifts were detected post-noise exposure. There was no change in speech discrimination scores and no individuals complained of tinnitus. The number of hours of exposure ranged from 1.5 to 8.5 hours (mean 5.2 hours). Recorded sound levels for instruments ranged from 119.6 dB at source to 73.1 decibels at 3 metres.

Although high sound levels are recorded in the orthopaedic operating theatre, the intermittent nature exposure to the intense noise may protect staff against hearing loss, speech discrimination difficulties and tinnitus.
Sudden hearing loss in intralabyrinthine haemorrhage in a child
Authors: Jang Chul Ho , Kim Young Ho
Published: July 2004

This paper reports an unusual case in which aseptic meningitis presented with sudden sensorineural hearing loss (SSNHL) associated with intralabyrinthine haemorrhage (ILH). A seven-year-old girl presented with sudden right-sided hearing loss with dizziness. She did not have a previous history of bleeding disorders. This child was assessed using audiograms and magnetic resonance imaging (MRI). The patient's hearing loss was irreversible. Steroid therapy was not effective. SSNHL associated with ILH can be one of the negative prognostic factors in children.
Memory for targets in a multi‐level simulated‐environment: A comparison between able‐bodied and physically disabled children
Authors: Wilson Paul N. , Foreman Nigel , Stanton Danaë , Duffy Hester
Published: July 2004

Two groups of children, one able‐bodied and the other with physical disabilities, explored a symmetrical three‐tiered virtual building that contained six distinctive target objects, two on each storey. In a subsequent test, the target objects were removed and participants were asked to make judgments of the directions to the former target locations from each floor in turn. At each test site, judgments were required for targets that were formerly on the same floor and for those on higher and lower floors. Relative tilt error scores suggested a bias for both groups, in that targets that were higher than the test location were judged as consistently lower than their actual position, whereas targets that were lower than the test location were judged as higher than their actual position. Absolute tilt errors revealed an asymmetry in both groups, with more accurate tilt errors for judgments directed to lower than higher floors. The relevance of these results for the source of the asymmetry is discussed.
Hand preference observed in large healthy samples: Classification, norms and interpretations of increased non‐right‐handedness by the right shift theory
Authors: Annett Marian
Published: July 2004

Healthy children and undergraduates were observed for hand preference and measured for hand skill in representative samples collected over some years. Writing and throwing were observed for 2844 participants drawn from primary, secondary and higher levels of education. The 12 actions of a standard questionnaire were observed for 2388 secondary school children and undergraduates. These findings provide normative data for comparison with selected samples that may be classified in a variety of ways, including subgroups previously defined and ordered for relative hand skill. Differences between the sexes were found only for certain subgroups of right‐mixed‐handers. Undergraduates were less variable for hand skill asymmetry than schoolchildren. Interpretations in the light of the RS theory show why statistical effects for comparisons with selected groups are likely to be small. Increased non‐right‐handedness may be caused by several influences on cerebral dominance, natural and pathological.
Wo viel Licht ist, ist starker Schatten – Softwareentwicklung in der Automobilindustrie (There's no Joy without Sorrow – Software Development in Automotive Industry)
Authors: Hartmann Jochen
Published: July 2004

Dieser Beitrag greift die Probleme auf, die sich aufgrund der unterschiedlichen Lebenszyklen der Informations- und der Automobiltechnik ergeben. Dabei werden diejenigen Probleme aufgezeigt, die bei der langfristigen Archivierung von Softwareentwicklungsumgebungen zu erwarten sind.
Automatisierte Interpretation von Zeitreihen am Beispiel von klinischen Bewegungsanalysen (Automated Interpretation of Time Series shown in Clinical Motion Analysis)
Authors: Loose Tobias , Dieterle Joachim , Mikut Ralf , Rupp Rüdiger , Abel Rainer , Schablowski Matthias , Bretthauer Georg , Gerner Hans Jürgen
Published: July 2004

Dieser Beitrag schlägt eine Strategie vor, um empirische Vorgehensweisen bei der Analyse von Zeitreihen zu formalisieren und in eine datenbasierte Auswertung zu integrieren. Bei dieser Strategie werden interpretierbare Merkmale extrahiert und verschiedene überwachte und unüberwachte Lernverfahren eingesetzt. Die Ergebnisse werden beispielhaft anhand der Analyse von Zeitreihen in der klinischen Bewegungsanalyse für Patienten mit inkompletter Querschnittlähmung demonstriert.
Beobachtergestützte Detektion von Fehlern in linearen zeitvarianten Systemen (Observer-based Fault Detection of Linear Time-varying Systems)
Authors: Zhang Ping , Ding Steven X.
Published: July 2004

Der vorliegende Beitrag befasst sich mit der Problematik der beobachtergestützten Fehlerdetektion für lineare kontinuierliche zeitvariante Systeme. Es wird zunächst der Entwurf von beobachtergestützten Fehlerdetektionssystemen mithilfe der eingeführten Operatoren und Normen als ein Optimierungsproblem formuliert. Es folgt dann die Herleitung analytischer Lösungen für dieses Optimierungsproblem, deren Kern aus der Lösung einer Riccati-Differential-Gleichung besteht. Abschließend wird das entwickelte Verfahren anhand eines Beispiels erläutert.
Faseroptische konfokale Mikroendoskopie für die In-vivo-Diagnostik (Fiber-Optical Confocal Microendoscopy for in-vivo Diagnostics)
Authors: Krohne Ingo
Published: July 2004

Eines der wichtigsten Ziele der modernen Medizin ist es, die Therapie und Diagnose für Patienten weniger belastend zu gestalten. Hierfür werden in zunehmendem Maße mikroelektronische und mikrooptische Technologien eingesetzt. In einem aktuellen Forschungsprojekt wird ein neuartiges Messsystem für den Einsatz in der In-vivo-Zellmikroskopie entwickelt. Es basiert auf dem Konzept eines miniaturisierten faseroptischen konfokalen Mikroskops.
Selection for Catalytic Function with Nucleic Acids
Authors: Breaker Ronald R.
Published: July 2004

For in vitro selection of catalytic polynucleotides, each new protocol must be designed to harness the desired catalytic activity to help propel the selection process itself. This unit gives guidelines for design of in vitro selection experiments for catalytic function. It outlines several representative protocols as examples of successful selection experiments, providing a conceptual basis for the design and implementation of new selective‐amplification protocols for nucleic acids.
Tensile stress relaxation of short‐coir‐fiber‐reinforced natural rubber composites
Authors: Geethamma V. G. , Pothen Laly A. , Rhao Bhaskar , Neelakantan N. R. , Thomas Sabu
Published: July 2004

The stress relaxation behavior of natural rubber (NR) and its composites reinforced with short coir fibers under tension was analyzed. The rate of stress relaxation was a measure of the increase in the entropy of the compounds: the higher the rate was, the greater the entropy was. At lower strain levels, the relaxation mechanism of NR was independent of strain level. However, the rate of relaxation increased with the strain level. Also, the strain level influenced the rate of stress relaxation considerably in the coir‐reinforced NR composites. However, the relaxation mechanisms of both the unfilled compound and the composite were influenced by the strain rate. The rate of relaxation was influenced by fiber loading and fiber orientation. From the rate of stress relaxation, we found that fiber–rubber adhesion was best in the composite containing fibers subjected to a chemical treatment with alkali, toluene diisocyanate, and NR solutions along with a hexaresorcinol system as a bonding agent. In this study, the stress relaxation curves could not be viewed as segments with varying slopes; however, a multitude of inflection points were observed on the curves. Hence, we propose neither a two‐step nor three‐step mechanism for the coir‐fiber‐reinforced NR composites as reported for some other systems. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 96–104, 2004
Thermal behavior of vinyl ester resin matrix composites reinforced with alkali‐treated jute fibers
Authors: Ray Dipa , Sarkar B. K. , Basak R. K. , Rana A. K.
Published: July 2004

The thermal behavior of vinyl ester resin matrix composites reinforced with jute fibers treated for 2, 4, 6, and 8 h with 5% NaOH was studied with Thermo‐gravimetric analysis and differential scanning calorimetry. The moisture desorption peak shifted to a higher temperature, from 37 to 58.3°C, for all the treated‐fiber composites because of improved wetting of the fibers by the resin and stronger bonding at the interface. The degradation temperature of the vinyl ester resin in the composites was lowered to 410.3°C from that of the neat resin, 418.8°C. The X‐ray diffraction studies showed increased crystallinity of the treated fibers, which affected the enthalpy of the α‐cellulose and hemicellulose degradation. The hemicellulose degradation temperature remained the same (299.7°C) in all the treated‐fiber composites, but the enthalpy associated with the hemicellulose degradation showed an increasing trend in the treated composites with a small increase in the weight loss. This could be attributed to the increased hydrogen bonding between the more accessible OH groups of the hemicellulose in the noncrystalline region of the jute fiber and the resin. The degradation temperature of α‐cellulose was lowered from 364.2 to 356.8°C in the treated composites. The enthalpy of α‐cellulose degradation showed a decreasing trend with a lowering of the weight loss. The crystalline regions of the fiber, consisting of closely packed α‐cellulose chains, were bonded with the resin mainly on the surface through hydrogen bonds and became more resistant to thermal degradation; this reduced the weight loss. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 123–129, 2004
Swelling and elasticity of poly (N‐isopropylacrylamide‐co‐4‐vinyl benzene sulfonic acid sodium salt) hydrogels
Authors: Gundogan Nermin , Melekaslan Demet , Okay Oguz
Published: July 2004

The mechanical properties and the swelling behavior of hydrogels based on N‐isopropylacrylamide (NIPA) and 4‐vinylbenzenesulfonic acid sodium salt (styrene sulfonate, SSA) monomers were investigated. The mole fraction of SSA in the comonomer feed varied between 0 and 1, whereas the crosslinker ratio was fixed at 1/85. Both the swelling and the elasticity data of the hydrogels swollen in water show that they are in the non‐Gaussian regime. The exponents found for the charge density dependence of the equilibrium swelling ratio as well as for the volume dependence of the gel elastic modulus are in good agreement with the predicted course of the non‐Gaussian elasticity of swollen hydrogels. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 135–141, 2004
Thermal and optical properties of PMMA–titania hybrid materials prepared by sol‐gel approach with HEMA as coupling agent
Authors: Yeh Jui‐Ming , Weng Chang‐Jian , Huang Kuan‐Yeh , Huang Hsi‐Ya , Yu Yuan‐Hsiang , Yin Chung‐Hung
Published: July 2004

A series of sol‐gel derived organic–inorganic hybrid materials consisting of organic poly(methyl methacrylate) (PMMA) and inorganic titania (TiO2) were successfully synthesized by using 2‐hydroxyethyl methacrylate (HEMA) as coupling agent. In this work, HEMA is first copolymerized with methyl methacrylate monomer at specific feeding ratios by using benzoyl peroxide (BPO) as initiator. Subsequently, the as‐prepared copolymer (i.e., sol‐gel precursor) is then cohydrolyzed with various contents of titanium butoxide to afford chemical bondings to the forming titania networks to give a series of hybrid materials. Transparent organic–inorganic hybrid materials with different contents of titania are always achieved. Effects of the material composition on the thermal stability, optical properties, and morphology of neat copolymer and a series of hybrid materials, in the form of both coating and free‐standing film, are also studied by differential scanning calorimetry, thermogravimetric analysis, UV–Vis transmission spectra, refractometer, and atomic force microscopy, respectively. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 400–405, 2004
Controlled degradation by melt processing with oxygen or peroxide of ethylene/propylene copolymers
Authors: Pucci Andrea , Lorenzi Davide , Coltelli Maria‐Beatrice , Polimeni Giulio , Passaglia Elisa
Published: July 2004

Ethylene/propylene copolymers with the same composition but different sequence of monomer distribution were submitted to thermal degradation in an inert atmosphere, in the presence of oxygen and/or free radical initiators. The analysis of the reaction products, consisting of lower molecular weight macromolecules with double bonds and oxygenated functional groups, was performed by viscosimetric, FTIR, NMR, and differential scanning calorimetry (DSC) analysis. The presence of linear ethylene blocks of different length with distinct melting temperatures was detected by the self‐annealing methods based on DSC. The results are used to evaluate the effect of the copolymer macromolecules' microstructure and the processing conditions on the degradation extent and the molecular structure of the degradation products. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 372–381, 2004
Verschiebungen des Bodenauflagers bei Baugruben auf der Grundlage der Mobilisierungsfunktion von Besler
Authors: Hettler Achim , Maier Thomas
Published: July 2004

In der Praxis ist es üblich, Baugrubenwände mit dem Trägermodell und unverschieblichen Auflagern zu berechnen. Dabei steht die Annahme eines unverschieblichen Bodenauflagers im Widerspruch zu dem aktivierten Erdwiderstand.

Mit Hilfe der Mobilisierungsfunktion von Besler können die Verformungsberechnungen von Baugrubenwänden verbessert werden, indem eine Verschiebung des Bodenauflagers eingeführt wird.

Für nichtbindige Böden liegen umfangreiche Untersuchungen vor. Der Ansatz eignet sich auch für bindige Böden, wie gezeigt wird. Allerdings fehlen hier noch grundsätzliche Studien zu den maßgebenden Parametern.
Ein erweitertes physikalisches Modell der pF‐Kurve für teilgesättigte grobkörnige Böden auf primäre Entwässerung und sekundäre Be‐ und Entwässerung
Authors: Zou Yazhou
Published: July 2004

Durch Analyse der Bewässerungs‐ und Entwässerungsvorgänge teilgesättigter grobkörniger Böden wird das physikalische Modell in [5] zur Beschreibung der pF‐Kurven bei primärer Entwässerung und bei sekundärer Bewässerung und Entwässerung erweitert. Dabei wird zusätzlich noch der Einfluß eingeschlossener Gasblasen im Porenwasser auf die pF‐Kurve berücksichtigt. Das erweiterte Modell wird durch Versuchsergebnisse verifiziert.
Wiederaufbau des Neuen Museums in Berlin – Tragwerksplanung pro Baudenkmalpflege
Authors: Eisele Gerhard , Gutermann Marc , Seiler Josef , Steffens Klaus
Published: July 2004

“Lässt kein Werk sich verstehen ohne dass seine Technik verstanden wäre, lässt diese sowenig sich verstehen ohne Verständnis des Werkes” [1]. Der Wiederaufbau des Neuen Museums in Berlin ist im Sinne Adorno's eine Herausforderung für alle Baubeteiligten. Historische Tragelemente, insbesondere gewölbeartige Bauteile, verfügen in der Regel über erstaunliche Tragfähigkeiten, die allerdings selten durch rechnerische Nachweisführung allein bestätigt werden können. An zwei Beispielen wird aufgezeigt, wie sich rechnerische und experimentelle Tragfähigkeitsanalyse ergänzen und damit Konstruktionselemente von höchster denkmalpflegerischer Bedeutung einer modernen Nutzung zugeführt werden können.
Sanierungsmaßnahmen am Dom St. Marien in Zwickau
Authors: Kühn Michael , Opitz Heinz
Published: July 2004

Der Dom St. Marien in Zwickau ist Zeugnis einer 880 Jahre alten und sehr wechselvollen Baugeschichte. Das Gebiet um die spätgotische dreischiffige Hallenkirche hat sich durch den Steinkohlenbergbau um durchschnittlich 4 m gesenkt und 1,30 m nach Südosten bewegt. Dadurch sind am Bauwerk erhebliche Beanspruchungen, Risse und andere Schäden entstanden. Maßnahmen zur Instandsetzung und zur Dauerüberwachung des Bauwerks werden beschrieben.
Sprengabbruch von Stahlbeton‐Schornsteinen
Authors: Werner Diethelm , Melzer Rainer
Published: July 2004

Der Sprengabbruch von Schornsteinen aus Stahlbeton wird i. d. R. von spezialisierten Firmen geplant und ausgeführt. Kenntnisse über die mit dem Sprengabbruch verbundenen Vorgänge sind dennoch sowohl für Planungen als auch für die Beratung mit Betroffenen wünschenswert. Da Sprengarbeiten mit i. d. R. beherrschbaren Gefahren verknüpft sind und in der hier betrachteten Größenordnung großes öffentliches Interesse genießen, haben die folgenden Ausführungen auch das Ziel, bestehende Vorurteile abzubauen. Folgende Aspekte sollen beschrieben werden: Fallvorgang, Erschütterungsausbreitung im Boden, Gefährdung benachbarter Bauwerke und weitere Schadensquellen.
Zerstörungsfreie Prüfung von jungem Beton mittels einer Ultraschallreflexionsmethode
Authors: Voigt Thomas , Dehn Frank , Shah Surendra P.
Published: July 2004

Die zuverlässige und zerstörungsfreie Bestimmung der Eigenschaften jungen Betons ist ein entscheidender Faktor für den Erfolg und den Fortschritt vieler Bauvorhaben. Der vorliegende Aufsatz beschreibt eine neue Methode zur Charakterisierung zementgebundener Werkstoffe in jungem Alter. Die Methode beruht auf der Messung des Reflexionskoeffizienten (bzw. des Reflexionsverlusts) hochfrequenter Scherwellen an der Grenzfläche zwischen einer Stahlplatte und z. B. Beton. Die beschriebenen Versuche haben gezeigt, daß die Reflexionsmethode in der Lage ist, den Erstarrungs‐ und Erhärtungsprozeß von Beton qualitativ und quantitativ zu beschreiben. Über einen ersten, erfolgreichen Feldversuch wird berichtet.
Progress towards Development of a Cholera Subunit Vaccine
Authors: Taylor Ronald K. , Kirn Thomas J. , Bose Niranjan , Stonehouse Emily , Tripathi Shital A. , Kováč Pavol , Wade William F.
Published: July 2004

Cholera, an enteric disease that can reach pandemic proportions, remains a world‐wide problem that is positioned to increase in incidence as changes in global climate or armed conflict spawn the conditions that enhance transmission to humans and, thus, precipitate epidemic cholera. An effective subunit cholera vaccine that can provide protective immunity with one parenteral immunization would be a major advantage over the existing oral vaccines that can require two doses for optimal protection. The existing vaccines are clearly effective in some settings, but are less so in others, especially with respect to specific groups such as young (2–5 years) children. In our efforts to develop a cholera subunit vaccine, we focused on two Vibrio cholerae antigens, LPS (lipopolysaccharide) and TCP (toxin co‐regulated pilus), that are known to induce protective antibodies in animal models and, in the case of anti‐LPS antibodies, to be associated with clinical protection of V. cholerae exposed or vaccinated individuals. This review discusses the current cholera vaccines and compares the advantages of a cholera subunit vaccine to that of the whole cell vaccines. We discuss the possible subunit antigens and prospective targeted use of a subunit cholera vaccine.
In the Quest for a Virtual Pseudo Receptor for Sandalwood‐Like Odorants. Part I
Authors: Chapuis Christian
Published: July 2004

Based on similarities between naturally occurring (−)‐(Z)‐β‐ or (+)‐(Z)‐α‐santalol ((−)‐ 1 or (+)‐2, resp.) and the reversed (E)‐configured synthetic derivatives from campholenal (7a), a simple model A was developed. Besides reconciliation of this stereochemical aspect, this initial model also tentatively explained the enantiodiscriminations as well as the large spectra of distances separating the OH function from the lipophilic quaternary center(s) reported for different classes of substrates. Evolution, modifications, and refinement of this imperfect model allied with the research for alternative possibilities are illustrated, along with a historical guideline, in the light of olfactively challenging synthetic seco‐substructures as well as literature reports. Despite evolution of the inadequate model A and a plausible interpretation of the lipophilic part, the topological positions of the OH function and its vicinal alkyl substituent could nevertheless not be fully ascertained by this approach. This apparently inconclusive empirical concept prompted us to turn our attention towards a computerized methodology, which will constitute the second and third part of this study.
Glutamine‐dependent changes in gene expression and protein activity
Authors: Curi R. , Lagranha C. J. , Doi S. Q. , Sellitti D. F. , Procopio J. , Pithon‐Curi T. C.
Published: July 2004

The functions of glutamine are many and include, substrate for protein synthesis, anabolic precursor for muscle growth, acid–base balance in the kidney, substrate for ureogenesis in the liver, substrate for hepatic and renal gluconeogenesis, an oxidative fuel for intestine and cells of the immune system, inter‐organ nitrogen transport, precursor for neurotransmitter synthesis, precursor for nucleotide and nucleic acid synthesis and precursor for glutathione production. In the present review information on the mechanism of glutamine action is presented. This amino acid has been shown to regulate the expression of several genes (such as p47phox, p22phox, gp91phox, α‐actin and fibronectin) and activate several proteins (such as ASK1, c‐myc, c‐jun and p70s6k). Copyright © 2004 John Wiley & Sons, Ltd.
NADPH oxidase produces reactive oxygen species and maintains survival of rat astrocytes
Authors: Liu Qing , Kang Jiu‐Hong , Zheng Rong‐Liang
Published: July 2004

Reactive oxygen species (ROS) produced by activated astrocytes have been considered to be involved in the pathogenesis of neurodegenerative diseases, while NADPH oxidase is an essential enzyme involved in ROS‐mediated signal transduction. The goal of the present study was to determine whether NADPH oxidase plays a role in ROS generation and cell survival in rat astrocytes. We found that the release of ROS in rat astrocytes was significantly increased by stimulation with calcium ionophore or opsonized zymosan, which are known to trigger a respiration burst in phagocytes by the NADPH oxidase pathway. Further study indicated that diphenylene iodonium (DPI), an inhibitor of NADPH oxidase, significantly suppressed the increase of ROS release caused by the calcium ionophore or opsonized zymosan. Cell survival assay and fluorescence double dyeing with acridine orange and ethidium bromide showed that DPI dose‐ and time‐dependently decreased the viability of normal astrocytes, whereas exogenous supplementation of H2O2 can reverse the survival of DPI‐treated astrocytes. For the first time, our results suggest that NADPH oxidase is an important enzyme for the generation of ROS in astrocytes, and the ROS generated by NADPH oxidase play an essential role in astrocyte survival. Copyright © 2004 John Wiley & Sons, Ltd.
Assessment of student learning outcomes at the institutional level
Authors: Serban Andreea M.
Published: July 2004

While the assessment movement has spanned more than two decades, there is great variation in its degree of implementation among community colleges throughout the country. Building on literature in the field, this chapter discusses and gives examples of concepts and major areas involved in the assessment of student learning at the institutional level.
The role of student learning outcomes in accreditation quality review
Authors: Beno Barbara A.
Published: July 2004

This chapter is designed to acquaint the reader with the context for accreditors' increased emphasis on student learning outcomes as a key indicator of institutional quality and on the use of learning assessment as a key strategy for guiding institutional improvement. It articulates accreditors' expectations for the presentation of evidence that the institution is using student learning outcomes assessment as part of its quality improvement efforts.
Synthesis, Structures and Electrochemical Properties of Nitro‐ and Amino‐Functionalized Diiron Azadithiolates as Active Site Models of Fe‐Only Hydrogenases
Authors: Liu Tianbiao , Wang Mei , Shi Zhan , Cui Hongguang , Dong Weibing , Chen Jiesheng , Åkermark Björn , Sun Licheng
Published: July 2004

Complex [{(μ‐SCH2)2N(4‐NO2C6H4)}Fe2(CO)6] (4) was prepared by the reaction of the dianionic intermediate [(μ‐S)2Fe2(CO)6]2−andN,N‐bis(chloromethyl)‐4‐nitroaniline as a biomimetic model of the active site of Fe‐only hydrogenase. The reduction of4by Pd‐C/H2under a neutral condition afforded complex [{(μ‐SCH2)2N(4‐NH2C6H4)}Fe2(CO)6] (5) in 67 % yield. Both complexes were characterized by IR,1H and13C NMR spectroscopy and MS spectrometry. The molecular structure of4, as determined by X‐ray analysis, has a butterfly 2Fe2S core and the aryl group on the bridged‐N atom slants to the Fe(2) site. Cyclic voltammograms of4and5were studied to evaluate their redox properties. It was found that complex4catalyzed electrochemical proton reduction in the presence of acetic acid. A plausible mechanism of the electrocatalytic proton reduction is discussed.
Scanning fluorescent microscopy analysis is applicable for absolute and relative cell frequency determinations
Authors: Bocsi József , Varga Viktor Sebestyén , Molnár Béla , Sipos Ferenc , Tulassay Zsolt , Tárnok Attila
Published: July 2004

Background

Flow cytometry (FCM) and laser scanning cytometry (LSC) are the routine techniques for fluorescent cell analysis. Recently, we developed a scanning fluorescent microscopy (SFM) technique. This study compares SFM to LSC (two slide‐based cytometry, SBC, techniques) and FCM, in experimental and clinical settings.

Methods

For the relative cell‐frequency determinations, HT29 colorectal cancer cells and Ficoll separated blood mononuclear cells (FSBMCs) were serially diluted (from 1:1 to 1:1,000) and measured by each of the three techniques. For the absolute cell number determinations (only for SBC) FSBMCs were smeared on slides, then HT29 cells were placed on the slide with a micromanipulator (5–50 cells). Tumor cells circulating in the peripheral blood were isolated by magnetic separation from clinical blood samples of colorectal cancer patients. All samples were double‐stained by CD45 ECD and CAM5.2 FITC antibodies. For slides, TOTO‐3 and Hoechst 33258 DNA dyes were applied as nuclear counter staining.

Results

In the relative cell frequency determinations, the correlations between the calculated value and measured values by SFM, LSC, and FCM were r2 = 0.79, 0.62, and 0.84, respectively (for all P < 0.01). In the absolute cell frequency determinations, SFM and LSC correlated to a high degree (r2 = 0.97; P < 0.01).

Conclusions

SFM proved to be a reliable alternative method, providing results comparable to LSC and FCM. SBC proved to be more suitable for rare‐cell detection than FCM. SFM with digital slides may prove an acceptable adaptation of conventional fluorescent microscopes in order to perform rare‐cell detection. © 2004 Wiley‐Liss, Inc.
Flow cytometric characterization of cell populations in bronchoalveolar lavage and bronchial brushings from patients with chronic obstructive pulmonary disease
Authors: Hodge Sandra J. , Hodge Greg L. , Holmes Mark , Reynolds Paul N.
Published: July 2004

Background

Chronic obstructive pulmonary disease (COPD) is a serious, chronic inflammatory disease of the airway associated with cigarette smoking. Leucocytes are involved in the inflammatory process in the airways in COPD. There is a need for accurate characterization of cellular populations in bronchoalveolar lavage (BAL) due to variation in the predominant cell types reported, which were investigated mostly with manual counting techniques.

Methods

Bronchial brushings and BAL were obtained from human subjects undergoing fiber optic bronchoscopy. Flow cytometry was applied to identify various cell types. Quenching of autofluorescence of BAL‐derived alveolar macrophages was achieved with η‐octyl β‐D‐galactopyranoside and crystal violet. Comparisons of cell counts obtained with flow cytometric and manual counting methods were performed.

Results

Correlation analysis showed that manual cell counting methods overestimated the percentage of macrophages when compared with flow cytometric methods (R2 = 0.54). There was also a small tendency by manual counting to underestimate the percentage of lymphocytes and neutrophils. Using flow cytometry, the percentage and absolute numbers of alveolar macrophages and lymphocytes in BAL were not significantly different between patients with COPD and control subjects. The percentage and absolute numbers of neutrophils were higher in BAL from patients with moderate to severe COPD.

Conclusions

This novel flow cytometric assay for identification of various cell types from heterogenous samples of BAL and bronchial brushing will allow further investigation of cell characteristics, such as cytokine production and receptor expression, and an accurate evaluation of apoptosis for different cell types and provide a rationale for urgently required effective treatments for COPD. © 2004 Wiley‐Liss, Inc.
Role of FGFR signaling in the morphogenesis of the Drosophila visceral musculature
Authors: Mandal Lolitika , Dumstrei Karin , Hartenstein Volker
Published: July 2004

We report in this study that the longitudinal visceral muscle founder cells (LVMFs), a population of cells that migrate along the midgut primordium and visceral mesoderm, require the function of the Drosophila fibroblast growth factor receptor (FGFR) homolog, Heartless (Htl). Htl is expressed in LVMFs before and during their migration, and mitogen‐activated protein K (MAPK) activity is present at the same stage. Embryos deficient for htl show an almost complete absence of longitudinal visceral fibers at late stages. In line with previous studies implicating FGFR signaling in morphogenetic movements, we conclude that the defect we observe in htl mutant embryos indicates a role of this signaling pathway in cell migration and/or differentiation of the LVMFs. Given that, in addition to hemocytes, LVMFs are the only cells of the Drosophila embryo that migrate over large distances, we propose that these cells represent a highly suitable system to dissect the role of signaling pathways in cell migration in Drosophila. Developmental Dynamics 231:342–348, 2004. © 2004 Wiley‐Liss, Inc.
Differential tissue development during embryogenesis and regeneration in an annelid
Authors: Myohara Maroko
Published: July 2004

The fragmenting potworm Enchytraeus japonensis (Oligochaeta, Annelida) reproduces asexually by dividing the body into several fragments that then regenerate to complete individuals in 4–5 days. Such large‐scale regeneration, however, occurs only in some invertebrates. To better our understanding of why regeneration is so limited in many animals, despite their ability to undergo embryonic development from the single cell of a fertilized egg, comparisons were made between regeneration and embryonic development of E. japonensis by using two methods: histochemistry for alkaline phosphatase (ALP) and immunohistochemistry with an antibody against acetylated tubulin that visualizes nervous system development. The analyses revealed that both ALP expression patterns and central nervous system development differ between embryogenesis and the regeneration, suggesting that regeneration is not a simple reiteration of embryogenesis but involves different regulatory mechanisms. The study provides a basis for the elucidation of mechanisms that are unique and crucial to regeneration. Developmental Dynamics 231:349–358, 2004. © 2004 Wiley‐Liss, Inc.
Raldh2 expression in optic vesicle generates a retinoic acid signal needed for invagination of retina during optic cup formation
Authors: Mic Felix A. , Molotkov Andrei , Molotkova Natalia , Duester Gregg
Published: July 2004

Three retinaldehyde dehydrogenase genes (Raldh1, Raldh2, and Raldh3) expressed in unique spatiotemporal patterns may control synthesis of retinoic acid (RA) needed for retina development. However, previous studies indicate that retina formation still proceeds normally in Raldh1‐/‐ mouse embryos lacking RA synthesis in the dorsal neural retina at the optic cup stage. Here, we demonstrate that Raldh2‐/‐ embryos lacking RA synthesis in the optic vesicle exhibit a failure in retina invagination needed to develop an optic cup. This was also observed in Raldh1‐/‐:Raldh2‐/‐ double mutants, which develop similarly. Both mutants retain RA activity in the lens placode associated with Raldh3 expression, but this RA activity is insufficient to induce optic cup formation. Maternal RA administration at the optic vesicle stage rescues optic cup formation in Raldh2‐/‐ and Raldh1‐/‐:Raldh2‐/‐ embryos, demonstrating that Raldh1 is not required during rescue of optic cup development. The optic cup of rescued Raldh1‐/‐:Raldh2‐/‐ embryos exhibits normal RA activity and this is associated with Raldh3 expression in the retina and lens. Thus, RA signaling initiates in the optic vesicle in response to Raldh2 but can be maintained during optic cup formation by a gene other than Raldh1, most likely Raldh3. Loss of optic vesicle RA signaling does not effect expression of early determinants of retina at the optic vesicle stage (Pax6, Six3, Rx, Mitf). Our findings suggest that RA functions as one of the signals needed for invagination of the retina to generate an optic cup. Developmental Dynamics 231:270–277, 2004. © 2004 Wiley‐Liss, Inc.
Rhombomere boundaries are Wnt signaling centers that regulate metameric patterning in the zebrafish hindbrain
Authors: Riley Bruce B. , Chiang Ming‐Yung , Storch Elly M. , Heck Rebecca , Buckles Gerri R. , Lekven Arne C.
Published: July 2004

The vertebrate hindbrain develops from a series of segments (rhombomeres) distributed along the anteroposterior axis. We are studying the roles of Wnt and Delta–Notch signaling in maintaining rhombomere boundaries as organizing centers in the zebrafish hindbrain. Several wnt genes (wnt1, wnt3a, wnt8b, and wnt10b) show elevated expression at rhombomere boundaries, whereas several delta genes (dlA, dlB, and dlD) are expressed in transverse stripes flanking rhombomere boundaries. Partial disruption of Wnt signaling by knockdown of multiple wnt genes, or the Wnt mediator tcf3b, ablates boundaries and associated cell types. Expression of dlA is chaotic, and cell types associated with rhombomere centers are disorganized. Similar patterning defects are observed in segmentation mutants spiel‐ohne‐grenzen (spg) and valentino (val), which fail to form rhombomere boundaries due to faulty interactions between adjacent rhombomeres. Stripes of wnt expression are variably disrupted, with corresponding disturbances in metameric patterning. Mutations in dlA or mind bomb (mib) disrupt Delta–Notch signaling and cause a wide range of patterning defects in the hindbrain. Stripes of wnt1 are initially normal but subsequently dissipate, and metameric patterning becomes increasingly disorganized. Driving wnt1 expression using a heat‐shock construct partially rescues metameric patterning in mib mutants. Thus, rhombomere boundaries act as Wnt signaling centers required for precise metameric patterning, and Delta signals from flanking cells provide feedback to maintain wnt expression at boundaries. Similar feedback mechanisms operate in the Drosophila wing disc and vertebrate limb bud, suggesting coaptation of a conserved signaling module that spatially organizes cells in complex organ systems. Developmental Dynamics 231:278–291, 2004. © 2004 Wiley‐Liss, Inc.
Fire behaviour of timber surfaces with perforations
Authors: Frangi Andrea , Fontana Mario , Schleifer Vanessa
Published: July 2004

Timber surfaces with perforations are unfavourable from a fire design point of view, since the perforations increase the surface area exposed to fire and facilitate an increased penetration of heat into the burning zone. This can lead to an increased burning rate in comparison with heavy timber surfaces. In order to enlarge the theoretical and experimental background of the fire behaviour of timber surfaces with perforations, a series of fire tests was performed on timber assemblies made of hollow core elements with acoustic perforations and sound absorbers placed behind the perforated acoustic layer. This type of element is commonly used to improve ceiling sound absorption.

The first part of the paper describes the results of the fire tests, in the second part a simplified calculation model for the burning rate is presented and compared with the test results. The model takes into account two different charring phases, before and after the perforated acoustic layer is completely charred. Good agreement between the test results and prediction of the calculation model is observed. Further the fire tests clearly showed that the charring rate during the first phase is mainly influenced by the size and the position of the perforations as well as the thickness of the perforated acoustic layer. A correlation between the charring rate and these parameters is also presented and compared with the test results. Copyright © 2004 John Wiley & Sons, Ltd.
A counseling intervention for caregivers: effect on neuropsychiatric symptoms
Authors: Senanarong Vorapun , Jamjumras Piyanuch , Harmphadungkit Kamolthip , Klubwongs Mayuree , Udomphanthurak Suthipol , Poungvarin Niphon , Vannasaeng Sathit , Cummings Jeffrey L.
Published: July 2004

Background

In Thailand, family caregivers have an important role in delivering care to patients with dementia. Most patients with dementia in Thailand and also in Western societies live in the community. Training caregivers may improve care of dementia patients.

Objective

We performed a treatment study of a six‐month caregiver intervention with group counseling and support with provision of techniques to cope with non‐cognitive symptoms of patients with dementia. We hypothesized that this caregiver intervention with group counseling and support would reduce behavioral and neuropsychiatric symptoms in the demented patients.

Subjects and methods

We conducted a parallel group intervention study. A manual for group counseling and support was developed focusing on education regarding dementia, behavioral analysis and intervention, and environmental adaptation. Fifty nonprofessional caregivers—25 from the control group and 25 from the study group—of patients with dementia from the memory clinic at Siriraj Hospital were alternately assigned to each group as they presented to the clinic if they met the inclusion criteria and agreed to participate. The Thai Mental State Examination (TMSE) was used to assess dementia severity. Forty‐five minute counseling sessions were conducted every 6–8 weeks for 6 months and assessments were conducted at 3 months and 6 months. The primary outcome measure was the Neuropsychiatric Inventory (NPI).

Results

A paired samples analysis of the NPI scores demonstrated a significant change of the total NPI scores at the end of six month from baseline in the intervention group (P = 0.045). Change from baseline of the comparison group was not significant. There was a trend towards improvement of the TMSE scores between the two groups at month six (p = 0.061). The result favored the treatment group.

Conclusion

This study provided evidence of the utility of a non‐pharmacologic intervention using group counseling in an out‐patient setting for caregivers of patients with dementia. Copyright © 2004 John Wiley & Sons, Ltd.
The utility of the Visual Analogue Scale for the assessment of depressive mood in cognitively impaired patients
Authors: Kertzman Semion , Aladjem Zoya , Milo Ron , Ben‐Nahum Zeev , Birger Moshe , Grinspan Haim , Weizman Abraham , Kotler Moshe
Published: July 2004

Background

Early detection of depression in elderly demented patients may assist in adequate treatment. The aim of this study was to evaluate the utility of Visual Analogue Scale for depression among demented and mild cognitively impaired elderly patients.

Methods

157 Patients, aged from 65 to 92 years, in a memory clinic were divided into two groups according to scores on the Mini Mental State Examination (MMSE): Demented group (62 patients) with MMSE scores from 16 to 23, and Mild Cognitively Impaired group (MCI‐95 patients) with MMSE scores from 24 to 29. Subjects were diagnosed for depression according to DSM‐IV criteria, using Hamilton Depression Rating Scale (HDRS) and a comprehensive clinical evaluation. All were administered a Visual Analogue Scale (VAS) for depression.

Results

In the demented group, 25 subjects were diagnosed as depressive. In the MCI group, 46 subjects were diagnosed as depressive. Mean VAS scores for the demented and MCI groups were similar, both for depressive and non‐depressive patients. Correlations between VAS scores with HDRS scores and with the clinical diagnosis were high, although somewhat lower for the demented group. Analyzing data with ROC curve technique yielded significantly different ROC curves. Optimal cutoff point for the demented group was VAS value of 60, and 50 for the MCI group.

Conclusions

VAS seems to be a useful tool for evaluation of depression among cognitively impaired patients. Severity of cognitive decline in the elderly may influence the cutoff points on VAS for detecting depression. Further large‐scale studies are needed to substantiate our observation. Copyright © 2004 John Wiley & Sons, Ltd.
Brain perfusion correlates of the apathy inventory dimensions of Alzheimer's disease
Authors: Benoit M. , Clairet S. , Koulibaly P. M. , Darcourt J. , Robert P. H.
Published: July 2004

Background

Apathy is defined as a lack of motivation in behavior, cognition and affect. This syndrome is frequent in various neuropsychiatric diseases but little is known about its pathophysiology.

Objectives

The aim of this study was to investigate the metabolic correlates of the behavioral, cognitive and emotional, aspects of apathy in Alzheimer's disease (AD).

Method<

Thirty AD patients were included. Lack of initiative, lack of interest and of emotional blunting were assessed with the Apathy Inventory (IA), a tool designed to provide a separate assessment of the behavioral, cognitive and emotional, aspects of apathy. Brain perfusion was measured by 99mTc‐labeled bicisate (ECD) single photon emission tomography.

Results

The Statistical Parametric Mapping software provides negative correlation between IA total score and brain perfusion in left and right superior orbito‐frontal gyrus, and to a lesser extent in left middle frontal gyrus (BA10). Lack of initiative score was negatively correlated with perfusion in right anterior cingulate cortex. Lack of interest score was negatively correlated with perfusion in right middle orbitofrontal gyrus). Emotional blunting score correlated negatively with in left superior dorsolateral prefrontal cortex activity.

Conclusion

These results underline that the cognitive, behavioral and affective components of motivation are mediated by different fronto‐sub‐cortical circuits and are differently lateralized. In particular, left prefrontal hypoperfusion is involved in emotional blunting, as it was often demonstrated in depressive disorders. These distinct components of apathy may be targeted by different therapeutic means, in which dopaminergic enhancement might play a major role. Copyright © 2004 John Wiley & Sons, Ltd.
Characteristics of the GPCOG, a screening tool for cognitive impairment
Authors: Brodaty Henry , Kemp Nicola M. , Low Lee‐Fay
Published: July 2004

Background

Early dementia diagnosis is aided by the use of brief screening tests; scores can be biased by patient and informant characteristics such as age, gender and education.

Objective

To assess whether the General Practitioner's Assessment of Cognition (GPCOG), a brief screening tool for detecting cognitive impairment comprising a patient cognitive test and questions to an informant, is biased by patient and informant characteristics.

Design

Sixty‐seven general practitioners recruited consecutive patients (with informants). Patients were subsequently assessed by a research psychologist, and DSM‐IV diagnoses assigned following a case‐conference.

Setting

Primary Care.

Subjects

Two hundred and eighty three home‐dwelling individuals, 11.3% of whom were aged 50–74 years with suspected memory problems and the rest aged 75 or more.

Methods

The GPCOG, Cambridge Mental Disorder of the Elderly Examination cognitive scale (CAMCOG), Geriatric Depression Scale (GDS), and the SF‐12 Health Survey (SF‐12) were administered and demographic data were collected and consensus DSM‐IV diagnoses of dementia made. Relationships between patient and informant characteristics and the GPCOG measure were examined using Pearson correlations and linear regression analyses.

Results

There were correlations in GPCOG‐patient scores with age, education and depression scores but on regression analysis only age was associated with the GPCOG‐patient section. The GPCOG‐informant section was free of bias.

Conclusions

The GPCOG has advantages for use in primary care and is free of many biases common in other scales. Copyright © 2004 John Wiley & Sons, Ltd.