bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of hydrogen charge on microscopic fatigue behaviour of annealed carbon steels
Authors: UYAMA H. , NAKASHIMA M. , MORISHIGE K. , MINE Y. , MURAKAMI Y.
Published: November 2006

The effects of hydrogen charge on cyclic stress–strain properties, slip band morphology and crack behaviour of annealed medium carbon steels (JIS‐S45C) were studied. The total strain range of the stress–strain hysteresis loop in the hydrogen‐charged specimen was smaller than that in the uncharged specimen. Localized slip bands were observed in the hydrogen‐charged specimen, while the slip bands were widely and uniformly distributed in the uncharged specimen. It is presumed that the decrease in the total strain range of the hysteresis loop is due to the slip localization caused by the hydrogen charge and cyclic loading. The sites of fatigue crack initiation were mostly at grain boundaries in the uncharged specimen. The sites of crack initiation in the hydrogen‐charged specimen were not only at grain boundaries but also at slip bands inside ferrite grains. These results imply that hydrogen enhances dislocation mobility along slip bands and results in slip localization. These slip bands then attract hydrogen. This mechanism of hydrogen–slip band interaction may play an important role in the hydrogen‐influenced metal fatigue.
Relations between different types of children's aggressive behavior and sociometric status among peers of the same and opposite gender
Authors: KERESTEŠ GORDANA , MILANOVIĆ ANITA
Published: November 2006

Croatian elementary school children in grades 4 to 6 (N= 151) reported on direct and indirect aggressive behaviors of their classmates. Acceptance and rejection by classmates were also assessed, employing the sociometric nomination technique. Correlational analyses revealed that both forms of aggression were related to peer rejection, but unrelated to peer acceptance. Girls’ aggression was more strongly related to peer rejection than boys’ aggression, independent of the type of aggression. Aggressive children of both genders tended to be more rejected by their same‐gender classmates than by classmates of the opposite gender. Results were discussed in terms of children's attitudes towards aggression, and gender stereotyped perception of appropriateness of aggressive behavior. A need to examine developmental changes and cultural differences in relationships between aggression and peer status was emphasized.
The Relationship Between the Recognition of Facial Expressions and Self‐Reported Anger in People with Intellectual Disabilities
Authors: Woodcock Kate A. , Rose John
Published: November 2006

Background  This study aims to examine the relationship between how individuals with intellectual disabilities report their own levels of anger, and the ability of those individuals to recognize emotions. It was hypothesized that increased expression of anger would be linked to lower ability to recognize facial emotional expressions and increased tendency to interpret facial expressions in a hostile or negative manner. It was also hypothesized increased levels of anger may lead to the altered perception of a particular emotion.

Method  A cross‐sectional survey design was used. Thirty participants completed a test of facial emotion recognition (FER), and a self‐report anger inventory (Benson & Ivins 1992) as part of a structured interview.

Results  Individuals with higher self‐reported anger did not show significantly reduced performance in FER, or interpret facial expressions in a more hostile manner compared with individuals with less self‐reported anger. However, they were less accurate in recognizing neutral facial emotions.

Conclusions  It is tentatively suggested that individuals with high levels of anger may be likely to perceive emotional content in a neutral facial expression because of their high levels of emotional arousal.
REVIEW OF UPPERMOST FURONGIAN TRILOBITES FROM SCANIA, SOUTHERN SWEDEN, BASED ON TYPE MATERIAL
Authors: TERFELT FREDRIK
Published: November 2006

Abstract:  The Scandinavian trilobites described in the classical papers by Moberg and Möller (1898) and Moberg (1898) are reviewed, based on the original type collections. The ten species and subspecies originally described are here considered to represent 12 species and subspecies, ranging in age from the latest Furongian (late Cambrian) through the Tremadocian (Early Ordovician). Lectotypes are selected for Parabolina (Parabolina) acanthura (Angelin), Acerocare ecorne Angelin and Westergaardia lata (Matthew). Leptoplastus claudicans (Moberg and Möller) is regarded as a junior subjective synonym of L. stenotus Angelin. These, and lectotypes formerly only figured by hand‐drawings, are illustrated by high‐resolution photographs.
Microvascular growth of 7,12‐dimethylbenz(α)anthracene‐induced adenocarcinomas in rats: histology and scanning electron microscopy of resin casts
Authors: Ninomiya H. , Inomata T. , Yoshida S.
Published: November 2006

Vascular changes at various stages of growth of 7,12‐dimethylbenz(α)anthracene (DMBA)‐induced mammary adenocarcinomas in 22 female Sprague‐Dawley rats were investigated using histology, immunohistochemistry and scanning electron microscopy (SEM) of corrosion casts. In the early stage of tumour growth, capillaries within the neoplasms were thin, with 8–10 μm diameter, and characterized by rows of vascular sprouts representing extensive neovascularization and formation of a high‐density capillary plexus. In the intermediate stage of tumour growth, the growing tumour was multi‐nodular and tumour cells were arranged in a tubulopapillary pattern. Capillaries formed spheroid vascular capsules and were characterized by dilation, to a diameter of 10–80 μm, and blind ends. In the late stage of tumour growth, a remarkable reduction in the number of vascular endothelial growth factor‐positive cells and Ki‐67‐stained nuclei was demonstrated. The tunica media of nutritive arteries displayed a tendency to atrophy. Many arteriovenous anastomoses between the major arteries and the veins were found in regions just before their entry into the tumour. The central regions of the tumour were degenerative and necrotic, and vasculature was confined to surface regions of the tumour, forming a basket‐like configuration around the avascular central regions. Resin leakages representing haemorrhage or oedema and distortions such as flattening, break‐off and strangulations of capillaries were frequently observed, all of which are known as late tumour signs. We concluded that these microvascular alterations might change the homogeneity of tumour perfusion and contribute to necrosis in central portions of the tumour.
Left Out: Trust and Social Capital Among Migrant Seasonal Farmworkers*
Authors: Chávez Maria L. , Wampler Brian , Burkhart Ross E.
Published: November 2006

Objectives. We analyze the levels of trust and social capital among an understudied group: migrant seasonal farmworkers (MSFW). MSFWs of today are likely to become the “Hispanics” of tomorrow, which means that understanding what affects the development of social capital of this group is critical to understanding how these individuals are incorporated—or not—into the U.S. polity.

Methods. We utilize logistic regression analysis and ordered logit analysis to analyze a data set of 555 MSFWs and comments from four focus groups in Idaho.

Results. We find that MSFWs have lower levels of generalized trust than do Hispanics nationally. We also find that MSFWs have low levels of trust toward whites and Mexican Americans.

Conclusions. We argue that an ethnic community's subgroups must be incorporated into our analysis of social capital, especially when these individuals are likely to become U.S. permanent residents or citizens.
The Adjunctive Role of Nonpulmonary Venous Ablation in the Cure of Atrial Fibrillation
Authors: ARRUDA MAURICIO , NATALE ANDREA
Published: November 2006

Atrial fibrillation is highly prevalent and accounts for significant morbidity, mortality, and health care costs. Catheter ablation has become a therapeutic option in the management of this challenging arrhythmia. To optimize procedure safety and long‐term efficacy, different ablation strategies have been evaluated, targeting either the triggers initiating atrial fibrillation or the substrate responsible for its maintenance. This report summarizes some of the innovative contributions on the adjunctive role of nonpulmonary venous ablation approaches in the cure of atrial fibrillation.
New Antiarrhythmic Agents for the Prevention and Treatment of Atrial Fibrillation
Authors: PADANILAM BENZY J. , PRYSTOWSKY ERIC N.
Published: November 2006

Rhythm control could become the preferred treatment strategy for atrial fibrillation (AF) if the available antiarrhythmic agents were more effective and safe. A subanalysis of the AFFIRM trial data suggested that rhythm control, if achieved without the adverse effects related to antiarrhythmic medications, may offer a significant survival advantage over rate control. This article reviews the new investigational pharmacologic and dietary agents being considered for the prevention and treatment of AF. Dronederone is a benzofurane similar to amiodarone, but without the iodine component, and is devoid of many of the amiodarone systemic toxicities. Azimilide is a delayed rectifier potassium channel blocker with use‐dependent effects. Agents that target the ultra rapid component of the delayed rectifier potassium current (IKur) have atrial myocyte specific properties and may be devoid of QT prolongation and torsade de pointes in clinical usage. Newer agents being studied also include fish oil, gap junction modulators, 5HT4 receptor antagonists, angiotensin‐converting enzyme inhibitors, angiotensin II receptor blockers, and HMG CoA reductase inhibitors. There is considerable hope that at least some of these agents will ultimately be available for more effective and safe clinical treatment and prevention of AF.
Labor Mobility and East Asian Integration
Authors: CHIA Siow Yue
Published: November 2006

East Asian economic integration is commonly analyzed in the context of trade in goods and services and capital flows, while labor flows have been very much neglected. Yet labor flows in the region are rapidly growing, given the diversity in levels of economic development, employment opportunities and wage levels, and the existence of labor surplus and deficit countries. Labor migration poses more benefits than costs for both sending and receiving countries, but there are more sensitivities toward labor flows than trade and capital flows. The characteristics and government policies are different for the unskilled and semiskilled foreign workers and for the professionals and highly skilled. Regional cooperation among countries is needed to manage the flows, reduce the incidence of illegal and undocumented workers, reduce the transaction costs of migration, and protect the rights of these workers.
Time-Dependent Fracture and Defect Assessment of Welded Structures at High Temperature
Authors: Xuan Fu-Zhen , Tu Shan-Tung , Wang Zhengdong
Published: November 2006

The present work reports several new insights into creep crack growth performance and defect assessment of welded structures at elevated temperature. First of all, an equivalent homogeneous model based on the limit load analysis is proposed to reflect the mismatch effects of the base and weld metals, the geometrical dimension of weldment constituents and the location of the pre-existing defects. Secondly, using the proposed equivalent homogeneous model, an estimation methodology for the time-dependent fracture mechanics parameter C* is developed in conjunction with the reference stress (RS) method and the GE/EPRI scheme. Such an estimation method was validated by using nonlinear finite element analysis of 48 compact tension (CT) specimens with various degrees of mismatch in creep behavior and different width of the welding seam. After that, the applicability of C* measurement recommended in ASTM E 1457 is re-examined for the CT specimen with a mismatched cross-weld. From the limit load analysis, a series of modifications for experimental C* estimation equation from ASTM E 1457 is introduced based on the proposed equivalent homogeneous model. Finally, a failure assessment diagram (FAD)-based method is presented for the welded structures at high temperatures. The application of such an approach to a welded cylinder with an internal circumference crack under axial tension is also reported in this paper.
Prediction of Fracture Appearance Transition Temperature of 2.25Cr-1Mo Steel Used in Hot-Wall Hydrofining Reactors
Authors: Tan Jinzhu , Huang Wenlong , Chao Y. J.
Published: November 2006

A kinetics model for temper embrittlement was employed as the basis for predicting the fracture appearance transition temperature (FATT) of 2.25Cr-1Mo steel used for hot-wall hydrofining reactors. Various heat treatments were performed to obtain different degrees of temper embrittlement for the steel. Charpy V-notch impact tests and Auger electron spectroscopy analysis were performed on embrittled 2.25Cr-1Mo steels to establish the relation between the shift of FATT and the change in the concentration of phosphorus segregated in the grain boundary of the steel. Based on the model and test data, a method of predicting the FATT at service time t was developed for the 2.25Cr-1Mo steel. Good agreement is obtained when the predicted values are compared to test data from open literature.
Lifetime measurement of metastable fluorine atoms using electron cyclotron resonance plasma source
Authors: Shimizu Masao , Ohmi Hiromasa , Kakiuchi Hiroaki , Yasutake Kiyoshi
Published: November 2006

The authors have measured the lifetime of metastable state (3sP5∕24) of F atoms by resonant laser-induced fluorescence method. For this experiment, a special 2.45GHz electron cyclotron resonance (ECR) plasma source, which is highly efficient in F radical generation and free from magnetic field leakage in front of the beam-emitting orifice, has been developed. Using the ECR plasma gun, the authors observed a precision fluorescence spectrum related to 3pD7∕204(F=4)→3sP5∕24(F=3) transition of F radicals, which made it possible to experimentally determine the longitudinal velocity distribution and the angular spread of the F radical beam. Based on these measured beam characteristics, the authors extracted a true decay curve of fluorescence intensity as a function of distance from the source and determined the lifetime of F metastable state (3sP5∕24) as 7.3±0.5μs.
In situ measurement of the ion incidence angle dependence of the ion-enhanced etching yield in plasma reactors
Authors: Belen Rodolfo Jun , Gomez Sergi , Kiehlbauch Mark , Aydil Eray S.
Published: November 2006

The authors propose and demonstrate a technique to determine the ion incidence angle dependence of the ion-enhanced etching yield under realistic plasma conditions and in situ in an arbitrary plasma reactor. The technique is based on measuring the etch rate as a function of position along the walls of features that initially have nearly semicircular cross sections. These initial feature shapes can be easily obtained by wet or isotropic plasma etching of holes patterned through a mask. The etch rate as a function of distance along the feature profile provides the etching yield as a function of the ion incidence angle. The etch rates are measured by comparing digitized scanning electron micrograph cross sections of the features before and after plasma etching in gas mixtures of interest. The authors have applied this technique to measure the ion incidence angle dependence of the Si etching yield in HBr, Cl2, SF6, and NF3 plasmas and binary mixtures of SF6 and NF3 with O2. Advantages and limitations of this method are also discussed.
Deposition profile of Ti film inside a trench and its correlation with gas-phase ionization in high-pressure magnetron sputtering
Authors: Nafarizal N. , Takada N. , Nakamura K. , Sago Y. , Sasaki K.
Published: November 2006

This article reports the relationship between the degree of ionization of Ti in the gas phase and the thickness profile of Ti film inside a trench in magnetron sputtering deposition. A conventional magnetron sputtering plasma source was used for depositing Ti films inside trenches formed on rf-biased SiO2 substrates. It was found that a high bottom coverage was obtained when a high gas pressure and a long distance between the target and the substrate were employed for the deposition. On the other hand, at a short distance between the target and the substrate, the bottom coverage was small and was almost independent of the gas pressure. The deposition profile was compared with the spatial distributions of Ti and Ti+ densities measured by laser-induced fluorescence (LIF) imaging spectroscopy. The LIF results revealed that the density ratio of Ti+ to Ti in the downstream region increased with the gas pressure up to 0.3, while in the upstream region, it was small (<0.05) and was roughly constant with the gas pressure. In the case with the enhanced density ratio of 0.3, the flux ratio of Ti+ to Ti was estimated to be 4.4. Hence, it was concluded that, with a high gas pressure and a long distance between the target and substrate, the deposition profile with a high bottom coverage was obtained by accelerating Ti+ toward the bottom of the trench. The high-pressure magnetron sputtering discharge is useful for enhancing the degree of ionization and the bottom coverage.
The experimental synthesis of random pressure fields: Practical feasibility
Authors: Maury Cédric , Bravo Teresa
Published: November 2006

A previous paper discussed the methodology for the synthesis of partially correlated random pressure fields using a near-field array of loudspeakers. The acoustic sources are optimally driven so that various random excitations are reproduced over a test surface, namely an acoustic diffuse field, a grazing incident plane wave, and turbulent boundary layer fluctuating loads. This paper shows the physical limitation performances and the practical feasibility of synthesizing these random pressure fields in a series of loudspeakers array simulation experiments. Spatial error criteria are proposed on the number of acoustic sources per unit correlation length. They are more representative than mean-square error criteria to quantify the accuracy with which the assumed correlation structures are experimentally reconstructed. Furthermore, structural and acoustic models are formulated to investigate how sensitive is the panel vibroacoustic response to inaccuracies in the synthesized excitations. It is discussed how the direct reproduction of the panel vibroacoustic response with a limited number of loudspeakers should be feasible within the frequency bandwidth for which the modes at resonance well couple with the excitation.
Cholesterol-Depleting Statin Drugs Protect Postmitotically Differentiated Human Neurons against Ethanol- and Human Immunodeficiency Virus Type 1-Induced Oxidative Stress In Vitro
Authors: Acheampong Edward , Parveen Zahida , Mengistu Aschalew , Ngoubilly Noel , Wigdahl Brian , Lossinsky Albert S. , Pomerantz Roger J. , Mukhtar Muhammad
Published: November 2006

The majority of human immunodeficiency virus type 1 (HIV-1)-infected individuals are either alcoholics or prone to alcoholism. Upon ingestion, alcohol is easily distributed into the various compartments of the body, particularly the brain, by crossing through the blood-brain barrier. Both HIV-1 and alcohol induce oxidative stress, which is considered a precursor for cytotoxic responses. Several reports have suggested that statins exert antioxidant as well as anti-inflammatory pleiotropic effects, besides their inherent cholesterol-depleting potentials. In our studies, postmitotically differentiated neurons were cocultured with HIV-1-infected monocytes, T cells, or their cellular supernatants in the presence of physiological concentrations of alcohol for 72 h. Parallel cultures were pretreated with statins (atorvastatin and simvastatin) with the appropriate controls, i.e., postmitotically differentiated neurons cocultured with uninfected cells and similar cultures treated with alcohol. The oxidative stress responses in the presence/absence of alcohol in these cultures were determined by the production of the well-characterized oxidative stress markers, 8-isoprostane-F2-α, total nitrates as an indicator for various isoforms of nitric oxide synthase activity, and heat shock protein 70 (Hsp70). An in vitro culture of postmitotically differentiated neurons with HIV-1-infected monocytes or T cells as well as supernatants from these cells enhanced the release of 8-isoprostane-F2-α in the conditioned medium six- to sevenfold (monocytes) and four- to fivefold (T cells). It was also observed that coculturing of HIV-1-infected primary monocytes over a time period of 72 h significantly elevated the release of Hsp70 compared with that of uninfected controls. Cellular supernatants of HIV-1-infected monocytes or T cells slightly increased Hsp70 levels compared to neurons cultured with uninfected monocytes or T-cell supernatants (controls). Ethanol (EtOH) presence further elevated Hsp70 in both infected and uninfected cultures. The amount of total nitrates was significantly elevated in the coculture system when both infected cells and EtOH were present. Surprisingly, pretreatment of postmitotic neurons with clinically available inhibitors of HMG-coenzyme A reductase (statins) inhibited HIV-1-induced release of stress/toxicity-associated parameters, i.e., Hsp70, isoprostanes, and total nitrates from HIV-1-infected cells. The results of this study provide new insights into HIV-1 neuropathogenesis aimed at the development of future HIV-1 therapeutics to eradicate viral reservoirs from the brain.
Structure-Based Identification of a Major Neutralizing Site in an Adenovirus Hexon
Authors: Pichla-Gollon Susan L. , Drinker Mark , Zhou Xiangyang , Xue Feng , Rux John J. , Gao Guang-Ping , Wilson James M. , Ertl Hildegund C. J. , Burnett Roger M. , Bergelson Jeffrey M.
Published: November 2006

Virus-specific neutralizing antibodies present an obstacle to the effective use of adenovirus vectors for gene therapy and vaccination. The specific sites recognized by neutralizing antibodies have not been identified for any adenovirus, but they have been proposed to reside within the hexon, in small regions of the molecule that are exposed on the capsid surface and possess sequences that vary among serotypes. We have mapped the epitopes recognized by a panel of seven hexon-specific monoclonal antibodies that neutralize the chimpanzee adenovirus 68 (AdC68). Surface plasmon resonance experiments revealed that the antibodies compete for a single hexon binding site, and experiments with synthetic peptides indicated that this site resides within just one small surface loop. Mutations within this loop (but not in other surface loops) permitted virus to escape neutralization by all seven monoclonal antibodies and to resist neutralization by polyclonal antisera obtained from animals immunized against AdC68. These results indicate that a single small surface loop defines a major neutralization site for AdC68 hexon.
Selective Restriction of Nef-Defective Human Immunodeficiency Virus Type 1 by a Proteasome-Dependent Mechanism
Authors: Qi Mingli , Aiken Christopher
Published: November 2006

The Nef protein enhances human immunodeficiency virus type 1 (HIV-1) infectivity by facilitating an early postentry step in the virus life cycle. We report here that the addition of MG132 or lactacystin, each a specific inhibitor of cellular proteasome activity, preferentially enhances cellular permissiveness to infection by Nef-defective versus wild-type HIV-1. Pseudotyping by the glycoprotein of vesicular stomatitis virus rendered Nef-defective HIV-1 particles minimally responsive to the enhancing effects of proteasome inhibitors. These results suggest that Nef enhances the infectivity of HIV-1 particles by reducing their susceptibility to proteasomal degradation in target cells.
Case study comparisons of computational fluid dynamics (CFD) modeling versus tracer testing for determining clearwell residence times in drinking water treatment
Authors: Templeton M R , Hofmann R , Andrews R C
Published: November 2006

Computational fluid dynamics (CFD) modeling and full-scale tracer tests (using barium or fluoride) were used to determine the baffle factors of clearwells at three Canadian water treatment facilities (two in Ottawa, Ontario, and one in Peterborough, Ontario). A variety of clearwell baffling configurations and a range of flow rates (35 to 257 MLD) were considered. Two-dimensional CFD modeling (no depth dimension) was conducted using commercially available software (Fluent 6.0®). Virtual particle tracking allowed simulation of the residence time distribution for each clearwell configuration and flow rate condition. The baffle factors (t10/θ) derived from the CFD modeling closely matched the values obtained from full-scale tracer testing (<10% difference in most cases). The results of the study suggest that CFD modeling can be a reliable alternative to tracer testing for determining clearwell residence times and can thereby provide improved estimates of chemical disinfection performance and disinfection by-product formation. Key words: computational fluid dynamics, tracer, clearwell, baffle factor, barium, fluoride, disinfection, drinking water.
Theoretical study of one- and two-photon absorption properties of olefin-linked paracyclophane oligomers
Authors: Zhang Xiang-Biao , Feng Ji-Kang , Ren Ai-Min , Sun Chia-Chung
Published: November 2006

The electronic structures and the one- and two-photon absorption (TPA) properties of two series of the olefin-linked paracyclophane (pCp) oligomers have been studied using AM1 and ZINDO-SOS methods. The relationship between the TPA cross sections and the molecular chain length is obtained. The maximum TPA cross section increases in proportion to Nα (N denotes the number of repeat units) and the values of α depend on different molecular structures. The olefin-linked pCp oligomers, which have good transparency and large TPA cross sections, are promising candidates for TPA materials.Key words: two-photon properties, paracyclophane oligomer, AM1, ZINDO-SOS.
Monometallic, homo-, and hetero-bimetallic complexes of a siloxy-bis(phosphinimide) ligand
Authors: Martinez Gema , Stephan Douglas W
Published: November 2006

Deprotonation of Me3SiNP(t-Bu)2Me with BuLi generates [Me3SiNP(t-Bu)2CH2Li] (1), which reacts with (Me2SiCl)2O to give the new siloxyl-bis(phosphinimine) ligand [Me3SiNP(t-Bu)2CH2SiMe2]2O (2). This ligand reacts with 1 or 2 equiv. of CpTiCl3 to give [CpTiCl2NP(t-Bu)2CH2SiMe2OCH2SiMe2P(t-Bu)2NSiMe3] (3) and [CpTiCl2NP(t-Bu)2CH2SiMe2]2O (4), similar to the species [CpNbCl3NP(t-Bu)2CH2SiMe2]2O (5) and [CpTiCl2NP(t-Bu)2(µ-O-(CH2SiMe2)2)- P(t-Bu)2NCpNbCl3] (6). Subsequent alkylations of these metal-halide derivatives afforded the analogous permethylated analogs 7–10, respectively. Reaction of 8 with B(C6F5)3 generates [(CpTiMe2NP(t-Bu)2CH2SiMe2)(CpTiMeNP(t-Bu)2CH2SiMe2)O][MeB(C6F5)] (11). Benzylation of 4 give the species [CpTiBz2NP(t-Bu)2CH2SiMe2]2O (12), which reacts subsequently with NC(2,6-Me2C6H3) to give a 1:1 mixture of the diastereoisomers of [CpTiBz(N=C(CH2Ph)(2,6-Me2C6H3))NP(t-Bu)2CH2SiMe2]2O 13a and 13b. These synthetic routes are described and the implications considered. X-ray structural data for compounds 2, 4, 8, and 10 are reported.Key words: phosphinimide ligands, bimetallic species, heterobimetallic compounds.
A rapid (one day), sensitive real-time polymerase chain reaction assay for detecting Escherichia coli O157:H7 in ground beef
Authors: Holicka Jane , Guy Rebecca A , Kapoor Anita , Shepherd David , Horgen Paul A
Published: November 2006

The purpose of this study was to apply our rapid, integrated double enrichment 5′ nuclease real-time polymerase chain reaction assay for the detection of Escherichia coli O157:H7 and evaluate its efficacy. The assay targeted ground beef, an important vehicle in disease epidemiology. The assay reliably determined in 8 h the presence of E. coli O157:H7 in ground beef at the level of 1 colony-forming unit (CFU)/g. The sensitivity and specificity of the assay were compared with that of standard enrichment diagnostic techniques. A correlation of 100% in detection was achieved to the limit of 1 CFU/g. This assay can be used as a rapid, automatic process for identification of E. coli O157:H7 in ground beef or can be integrated with standard culture procedures, resulting in considerable cost and time savings.Key words: real-time PCR, E. coli O157:H7, ground beef, molecular diagnostics, rapid O157:H7 assay.
Étude de la contamination microbienne des myes (Mya arenaria) de la rive nord de l'estuaire maritime du fleuve Saint-Laurent (Québec, Canada)
Authors: Lévesque Benoît , Gagnon Fabien , Valentin Alexandra , Cartier Jacques-François , Chevalier Pierre , Cardinal Pierrette , Cantin Philippe , Gingras Suzanne
Published: November 2006

The aims of the present study were to assess the microbial quality of Mya arenaria clams from the north shore of the St. Lawrence River estuary and to validate various microbial indicator microorganisms of bivalve mollusks contamination. Clams were collected from nine sites, including four harvesting sites closed by virtue of the Canadian Shellfish Sanitation Program (CSSP). Six contamination indicators (fecal coliforms, somatic coliphages, F-specific coliphages, fecal streptococci, Clostridium perfringens, and Escherichia coli) and four pathogens (Campylobacter sp., Cryptosporidium parvum, Giardia sp., and Salmonella sp.) were identified in the clams. Indicators sensibility, specificity and predictive values with respect to the presence of pathogens were calculated. Pathogenic microorganisms detection frequency in clams was important (92%). Globally, pathogens tend to be less frequently detected in opened harvesting sites (p = 0.086). Although the assessed indicators were not perfect, when F-specific coliphages are associated with E. coli or fecal coliforms, a good sensibility (62%–64%) and good positive predictive value (88%) with respect to the investigated pathogens are obtained.Key words: mollusks, coliforms, Giardia, Cryptosporidium, Campylobacter.[Journal translation]
Patrons de reproduction des femelles d’isard (Rupicapra pyrenaica pyrenaica) dans une population non chassée et conséquences démographiques
Authors: Crampe Jean-Paul , Loison Anne , Gaillard Jean-Michel , Florence Étienne , Caens Patrick , Appolinaire Joël
Published: November 2006

From the long-term monitoring of isard females ( Rupicapra pyrenaica pyrenaica Bonaparte, 1845) marked in two areas of the Parc National des Pyrénées (France) with a quite constant population size for 20 years, we have conducted an analysis of age variation in recruitment (estimated as the proportion of offspring surviving through the winter per female). As predicted for a well-established high-density population, recruitment rates were low for young females (0.156 at 3 years of age and 0.221 at 4 years of age), but also for prime-aged females (0.414 per year for 5–16 year old females). No female older than 16 that we monitored recruited in any year. Recruitment rates were highly variable among females, among years (0.183 in 2002 vs. 0.635 in 1996 for prime-age females), and among areas (0.562 kid at Mayouret vs. 0.359 at Péguère). The use of an age-structured demographic model allowed us then to compare population dynamics between the well-established isard population in the Park and the colonizing population of isards at Bazès, in the eastern part of the Pyrénées. As predicted, the natural rate of increase of the isard population was much higher at Bazès (1.262) than in the Park (1.037). Likewise, the age structure of isard in the Park markedly differed from that obtained at Bazès (50% of females were younger than 5 years of age, and 19% were older than 10 years of age in the Park versus 67% and only 3.6%, respectively, at Bazès). Such differences in both population growth and age structure between isard populations with contrasted demographic regimes were well illustrated by marked differences in generation time (4.97 years at Bazès vs. 8.25 years in the Park). Our comparative study therefore demonstrates that generation time can vary markedly in relation to the demographic status within a given species.
DARK CURRENTS AND IMPACT IONIZATION COEFFICIENTS IN THE InP-InGaAsP DOUBLE HETEROSTRUCTURES
Authors: OZER M. , AHMETOGLU M. , APRAILOV N.
Published: November 2006

The dependence of reverse-biased leakage current on both voltage and temperature for InP - In x Ga 1-x As y P 1-y DH (double heterostructures) has been analyzed. We find that at the whole of the temperature range and at a wide range of reverse bias voltages, the reverse current varies exponentially with applied voltage, indicating that the band-to-band tunneling current mechanism prevails. An agreement is obtained between theory and experimental results. The tunneling current becomes substantial at peak junction electric fields as low as 105 V/m due to the small direct energy gaps and small effective masses of the structures tested. The process of breakdown in the investigated structures was of the avalanche type. The impact ionization coefficients in In x Ga 1-x As y P 1-y have been experimentally determined for composition x=0.68.
FEYNMAN PROPAGATOR FOR AN ELECTRON IN A QUANTUM DOT IN THE PRESENCE OF A UNIFORM MAGNETIC FIELD
Authors: FAN HONG-YI , JIANG NIAN-QUAN
Published: November 2006

By using the magnetic entangled state 〈λ| representation and the squeezing transform we derive Feynman propagator for a charged particle in a quantum dot in the presence of a uniform magnetic field. It is the neat expression of the squeezing operator in 〈λ| representation that provides the concise way and the brevity. The partition function of this sytem is thus obtained.
Teaching insect retinal physiology with newly designed, inexpensive micromanipulators
Authors: Krans Jacob , Gilbert Cole , Hoy Ron
Published: November 2006

In this article, we detail how to produce two inexpensive micromanipulators that offer high precision (∼25 μm) along a single axis of movement. The more expensive of the designs provides improved versatility along multiple axes. Both manipulators offer substantial savings over commercially available micromanipulators with comparable capabilities. Plans and instructions are given such that a novice can produce the manipulators with simple tools. The manipulators are designed to serve undergraduate teaching exercises in physiology. An electroretinogram exercise is suggested in adult house flies ( Musca) or flesh flies ( Neobellieria). Measuring the intensity-response function and temporal characteristics of visual transduction are discussed. A brief introduction to the field of visual transduction and the physiology of the laboratory exercises is provided as well.
Language and the Aging Brain: Patterns of Neural Compensation Revealed by Functional Brain Imaging
Authors: Wingfield Arthur , Grossman Murray
Published: November 2006

Human aging brings with it declines in sensory function, both in vision and in hearing, as well as a general slowing in a variety of perceptual and cognitive operations. Yet in spite of these declines, language comprehension typically remains well preserved in normal aging. We review data from functional magnetic resonance imaging (fMRI) to describe a two-component model of sentence comprehension: a core sentence-processing area located in the perisylvian region of the left cerebral hemisphere and an associated network of brain regions that support the working memory and other resources needed for comprehension of long or syntactically complex sentences. We use this two-component model to describe the nature of compensatory recruitment of novel brain regions observed when healthy older adults show the same success at comprehending sentences as their younger adult counterparts. We suggest that this plasticity in neural recruitment contributes to the stability of language comprehension in the aging brain.
Connection theory on differentiable fibre bundles: A conciseintroduction
Authors: Iliev Bozhidar Z.
Published: November 2006

The paper contains a partial review on the general connection theory on differentiable
fibre bundles. Particular attention is paid on (linear) connections on vector bundles. The
(local) representations of connections in frames adapted to holonomic and arbitrary frames are considered.
LIF Upregulates Expression of NK‐1R in NHBE Cells
Authors: Hu Cheng-Ping , Feng Jun-Tao , Tang Yu-Ling , Zhu Jin-Qi , Lin Min-Juan , Yu Ming-En
Published: November 2006

Leukemia inhibitory factor (LIF), a cytokine at the interface between neurobiology and immunology, is mainly mediated through JAK/STAT pathway and MAPK/ERK pathway. Evidence suggested LIF is related to the higher expression of neurokinin‐1 receptor (NK‐1R) in asthma. In this study, the immunohistochemistry stain showed the expressions of NK‐1R, LIF, p‐STAT3, and p‐ERK1/2 in the lung tissues of allergic rats were increased compared with the controls, and the main positive cell type was airway epithelial cell. Normal human bronchial epithelial cells were treated with LIF in the presence or absence of AG490 (JAK2 inhibitor), PD98059 (MEK inhibitor), and the siRNA against STAT3. Western blot and RT‐PCR indicated that LIF induced the expression of NK‐1R, which was inhibited by the inhibitors mentioned above. No significant interaction was found between JAK/STAT pathway and MAPK/ERK pathway. In summary, bronchial epithelial cell changes in asthma are induced by LIF which promotes the expression of NK‐1R, and JAK/STAT pathway and MAPK/ERK pathway may participate in this process.
LKB1 Is Recruited to the p21/WAF1 Promoter by p53 to Mediate Transcriptional Activation
Authors: Zeng Ping-Yao , Berger Shelley L.
Published: November 2006

The tumor suppressor LKB1 is an evolutionarily conserved serine/threonine kinase. In humans, LKB1 can be inactivated either by germ-line mutations resulting in Peutz-Jeghers syndrome or by somatic mutations causing predisposition to multiple sporadic cancers. LKB1 has wide-ranging functions involved in tumor suppression and cell homeostasis, including establishing cell polarity, setting energy metabolic balance (via phosphorylation of AMP-dependent kinase), regulating the cell cycle, and promoting apoptosis. LKB1 function was previously linked to the tumor suppressor p53 and shown to activate the p53 target gene p21/WAF1. In this study, we further investigated LKB1 activation of the p21/WAF1 gene and addressed whether LKB1 is directly involved at the gene promoter. We find that, consistent with previous studies, LKB1 stabilizes p53 in vivo, correlating with activation of p21/WAF1. We show that LKB1 physically associates with p53 in the nucleus and directly or indirectly phosphorylates p53 Ser15 (previously shown to be phosphorylated by AMP-dependent kinase) and p53 Ser392. Further, these two p53 residues are required for LKB1-dependent cell cycle G1 arrest. Chromatin immunoprecipitation analyses show that LKB1 is recruited directly to the p21/WAF1 promoter, as well as to other p53 activated promoters, in a p53-dependent fashion. Finally, a genetic fusion of LKB1 to defective p53, deleted for its activation domains, promotes activation of p21/WAF1. These results indicate that LKB1 has a direct role in activation of p21/WAF1 gene. (Cancer Res 2006; 66(22): 10701-8)
Osteoclasts Direct Bystander Killing of Bone Cancer
Authors: Ramnaraine Margaret L. , Mathews Wendy E. , Donohue James M. , Lynch Christine M. , Goblirsch Michael J. , Clohisy Denis R.
Published: November 2006

Primary and metastatic bone cancers are difficult to eradicate and novel approaches are needed to improve treatment and extend life. As bone cancer grows, osteoclasts, the principal bone-resorbing cells of the body, are recruited to and activated at sites of cancer. In this investigation, we determined if osteoclast lineage cells could function as a cell-based gene delivery system to bone cancers. We used the cytosine deaminase (CD) 5-fluorocytosine (5-FC) enzyme/prodrug system and studied bone marrow and bones from transgenic mice expressing a novel CD gene regulated by the osteoclast tartrate-resistant acid phosphatase (TRAP) gene promoter (Tg/NCD). DsRed2-labeled 2472 sarcoma cells were placed in Tg/NCD osteoclastogenic cultures and treated with 5-FC. 5-FC treatment resulted in profound bystander killing (90%; P < 0.05). The effect of 5-FC treatment on osteoclast lineage cells was most dramatic when administered at the beginning of the 7-day cultures, suggesting that mature osteoclasts are less sensitive to 5-FC. Evaluation of osteoclast-directed bystander killing in vivo revealed dramatic killing of bone cancer with only a modest effect on osteoclast number. Specifically, 5-FC treatment of tumor-bearing Tg/NCD mice or Tg/NCD bone marrow transplanted C3H mice (Tg/NCD-C3H) resulted in 92% and 44% reductions in tumor area, respectively (P < 0.05). Eight of ten 5-FC-treated Tg/NCD mice had complete bone tumor killing and five of six 5-FC-treated Tg/NCD-C3H mice had reduced tumor compared with controls. In addition, Tg/NCD osteoclasts were resistant to 5-FC treatment in vivo, a very important feature, as it identifies osteoclasts as an ideal CD gene delivery system. (Cancer Res 2006; 66(22): 10929-35)
In vivo Activity of the Cleaved Form of Soluble Urokinase Receptor: A New Hematopoietic Stem/Progenitor Cell Mobilizer
Authors: Selleri Carmine , Montuori Nunzia , Ricci Patrizia , Visconte Valeria , Baiano Antonio , Carriero Maria Vincenza , Rotoli Bruno , Rossi Guido , Ragno Pia
Published: November 2006

Cleaved forms of soluble urokinase receptor (c-suPAR) have been detected in body fluids from patients affected by various tumors. We recently reported increased c-suPAR levels in sera of healthy donors during granulocyte colony-stimulating factor (G-CSF)–induced mobilization of CD34+ hematopoietic stem cells (HSC). In vitro, c-suPAR or its derived chemotactic peptide (uPAR84-95) stimulated migration of human CD34+ HSCs and inactivated CXCR4, the chemokine receptor primarily responsible for HSC retention in bone marrow. These results suggested that c-suPAR could potentially contribute to regulate HSC trafficking from and to bone marrow. Therefore, we investigated uPAR84-95 effects on mobilization of mouse CD34+ hematopoietic stem/progenitor cells (HSC/HPC). We first showed that uPAR84-95 stimulated in vitro dose-dependent migration of mouse CD34+ M1 leukemia cells and inactivated murine CXCR4. uPAR84-95 capability to induce mouse HSC/HPC release from bone marrow and migration into the circulation was then investigated in vivo. uPAR84-95 i.p. administration induced rapid leukocytosis, which was associated with an increase in peripheral blood CD34+ HSCs/HPCs. In vitro colony assays confirmed that uPAR84-95 mobilized hematopoietic progenitors, showing an absolute increase in circulating colony-forming cells. uPAR84-95 mobilizing activity was comparable to that of G-CSF; however, neither synergistic nor additive effect was observed in combining the two molecules. These findings show for the first time in vivo biological effects of c-suPAR. Its capability to mobilize HSCs suggests potential clinical applications in HSC transplantation. (Cancer Res 2006; 66(22): 10885-90)
Chemiphoresis of montmorillonite particles
Authors: Helmy A. K. , Natale I. M. , Mandolesi M. E. , Santamaria R. M.
Published: November 2006

The chemiphoresis of montmorillonite saturated with Na, K, Li or Ca was studied in a system where corrosive dissolution of Al, Fe, Zn or Cu metal plates took place in the presence of HF and H2O2. The deposition of the clay as well as metal dissolution were found to be a function of indicating that the electrochemical reaction is controlled principally by diffusion of the reacting species to the metal-liquid interface. The deposition increased with clay concentration and was lower for Ca-clay than for Na-, K- or Li-clay. It is shown that chemiphoresis alone does not provide sufficient data for the calculation of particle mobility and that other types of measurement are necessary. A relationship between particle deposition and electrical conductivity was developed, and examined experimentally with satisfactory results.
Impaired Pain Sensation in Mice Lacking Prokineticin 2
Authors: Hu Wang-Ping , Zhang Chengkang , Li Jia-Da , Luo Z David , Amadesi Silvia , Bunnett Nigel , Zhou Qun-Yong
Published: November 2006

Prokineticins (PKs), consisting of PK1 and PK2, are a pair of newly identified regulatory peptides. Two closely related G-protein coupled receptors, PKR1 and PKR2, mediate the signaling of PKs. PKs/PKRs participate in the regulation of diverse biological processes, ranging from development to adult physiology. A number of studies have indicated the involvement of PKs/PKRs in nociception. Here we show that PK2 is a sensitizer for nociception. Intraplantar injection of recombinant PK2 resulted in a strong and localized hyperalgesia with reduced thresholds to nociceptive stimuli. PK2 mobilizes calcium in dissociated dorsal root ganglion (DRG) neurons. Mice lacking the PK2 gene displayed strong reduction in nociception induced by thermal and chemical stimuli, including capsaicin. However, PK2 mutant mice showed no difference in inflammatory response to capsaicin. As the majority of PK2-responsive DRG neurons also expressed transient receptor potential vanilloid (TRPV1) and exhibited sensitivity to capsaicin, TRPV1 is likely a significant downstream molecule of PK2 signaling. Taken together, these results reveal that PK2 sensitize nociception without affecting inflammation.
Placental RNA in Maternal Plasma
Authors: TSUI NANCY B. Y. , DENNIS LO Y. M.
Published: November 2006

Abstract:  The recent demonstration of the presence of placenta‐derived fetal RNA in maternal plasma has opened up new opportunities for noninvasive prenatal investigation. Circulating fetal RNA analysis could in principle be applied to all pregnancies without the limitations by fetal gender or polymorphisms between the mother and fetus. The use of fetus‐ or disease‐specific circulating RNA markers would greatly increase the number of markers that can be used for prenatal monitoring. With the recent advances in microarray technology, new placenta‐derived plasma RNA markers could be rapidly identified. These newly identified placental transcripts were robustly detectable in maternal plasma and were pregnancy‐specific. Remarkably, the relative concentrations of the placental mRNA in maternal plasma directly reflect the gene expression patterns in the placenta, an observation which suggests that placental gene expression level plays a predominant role in determining the placental mRNA concentrations in maternal plasma. Thus, fetal mRNA measurement in maternal plasma may be a useful tool for noninvasive prenatal placental gene expressing profiling.
Toward a Genealogy of Modernism: Herder, Nietzsche, History
Authors: Zusi Peter
Published: November 2006

Peter Zusi is lecturer in Slavic languages and literatures at Harvard University. His recent publications include “The Style of the Present: Karel Teige on Constructivism and Poetism,” Representations, no. 88 (2004), and “`Wie ein Kind ist unser Volk': Hybrid Identity and National Consciousness in Rilke's Zwei Prager Geschichten,” German Quarterly 79 (2006).