bluuebunny/crossref_metadata_2025 huggingface dataset:
Radical Cyclizations of Alkenyl Acylphosphonate Derivatives under Thermal and Photochemical Conditions
Authors: Cho Chang Ho , Kim Sunggak , Yamane Motoki , Miyauchi Hironori , Narasaka Koichi
Published: August 2005

The use of alkenyl acylphosphonate and acylphosphine oxide derivatives as acceptors in radical cyclizations was studied under thermal and photochemical conditions, respectively. The cyclizations of alkenyl acylphosphonates under thermal conditions occurred smoothly in refluxing dioxane using benzoyl peroxide as an initiator; the addition of diethyl phosphite increased the chemical yield. Photochemically induced cyclizations of alkenyl acyldiphenylphosphine oxides at 300 nm gave similar results, although a notable difference was observed in one case. The intramolecular cyclization of S-but-3-enyl phosphinothiolformates occurred under thermal and photochemical conditions, providing thiolactones, whereas S-pent-4-enyl phosphinothiolformate afforded the tetrahydrothiophene derivative under similar conditions.
Decomposition Behavior of PCDD/F Isomers in Incinerator Gases under Electron-Beam Irradiation
Authors: Hirota Koichi , Kojima Takuji
Published: August 2005

The decomposition behavior under electron-beam irradiation was examined for polychlorinated dibenzo-p-dioxin (PCDD, polychlorinated dibenzo[b,e][1,4]dioxin) and polychlorinated dibenzofuran (PCDF) isomers in incinerator gases at a temperature of 473 K. Significant decomposition was obtained for all PCDD isomers over the investigated absorbed doses, which resulted from oxidation reactions with OH radicals yielded by electron-beam irradiation. In the case of PCDFs, specific isomers having symmetrical structures, such as 1,2,8,9-, 2,3,7,8-, and 3,4,6,7-TeCDFs, were yielded through the dechlorination of PeCDF isomers. Thermal electrons probably played a role in the dechlorination of PeCDF isomers. Simultaneous formation and subsequent destruction were observed in the electron-beam treatment of TeCDFs in incinerator gases.
Imaging of Charged Micropatterned Monolayer Surfaces by Chemical Force Microscopy
Authors: Koga Tomoyuki , Otsuka Hideyuki , Takahara Atsushi
Published: August 2005

Chemical force microscopy (CFM) was applied for the lateral force microscopic imaging of micropatterned organosilane monolayer surfaces with oppositely charged phases using chemically modified cantilever tips. Chemically modified cantilever tips with oxidized mercaptosilane, aminosilane, and unmodified cantilever tip were employed as a tip for CFM. Lateral force imaging of the micropatterned surface with opposite charge was successfully achieved by controlling the pH of the aqueous solution in consideration of the electrostatic condition of functional groups on the cantilever tip and substrate surface.
Bidding with Securities: Auctions and Security Design
Authors: DeMarzo Peter M , Kremer Ilan , Skrzypacz Andrzej
Published: August 2005

We study security-bid auctions in which bidders compete for an asset by bidding with securities whose payments are contingent on the asset's realized value. In formal security-bid auctions, the seller restricts the security design to an ordered set and uses a standard auction format (e.g., first- or second-price). In informal settings, bidders offer arbitrary securities and the seller chooses the most attractive bid, based on his beliefs, ex post. We characterize equilibrium and show that steeper securities yield higher revenues, that auction formats can be ranked based on the security design, and that informal auctions lead to the lowest possible revenues.
Optimal Expectations
Authors: Brunnermeier Markus K , Parker Jonathan A
Published: August 2005

Forward-looking agents care about expected future utility flows, and hence have higher current felicity if they are optimistic. This paper studies utility-based biases in beliefs by supposing that beliefs maximize average felicity, optimally balancing this benefit of optimism against the costs of worse decision making. A small optimistic bias in beliefs typically leads to first-order gains in anticipatory utility and only second-order costs in realized outcomes. In a portfolio choice example, investors overestimate their return and exhibit a preference for skewness; in general equilibrium, investors' prior beliefs are endogenously heterogeneous. In a consumption-saving example, consumers are both overconfident and overoptimistic.
The Market for News
Authors: Mullainathan Sendhil , Shleifer Andrei
Published: August 2005

We investigate the market for news under two assumptions: that readers hold beliefs which they like to see confirmed, and that newspapers can slant stories toward these beliefs. We show that, on the topics where readers share common beliefs, one should not expect accuracy even from competitive media: competition results in lower prices, but common slanting toward reader biases. On topics where reader beliefs diverge (such as politically divisive issues), however, newspapers segment the market and slant toward extreme positions. Yet in the aggregate, a reader with access to all news sources could get an unbiased perspective. Generally speaking, reader heterogeneity is more important for accuracy in media than competition per se.
The Political Economy of Corporate Governance
Authors: Pagano Marco , Volpin Paolo F
Published: August 2005

We analyze the political determinants of investor and employment protection. Our model predicts that proportional electoral systems are conducive to weaker investor protection and stronger employment protection than majoritarian systems. This prediction is consistent with international panel data evidence. The proportionality of the voting system is significantly and negatively correlated with shareholder protection in a panel of 45 countries, and positively correlated with employment protection in a panel of 21 OECD countries. Other political variables also affect regulatory outcomes, especially for the labor market. The origin of the legal system has some additional explanatory power only for employment protection.
The role of arbitration of discordant reports at double reading of screening mammograms
Authors: Ciatto S , Ambrogetti D , Risso G , Catarzi S , Morrone D , Mantellini P , Rosselli Del Turco M
Published: August 2005

Objective: To asses the effectiveness of arbitration of discordant double readings in mammography screening.

Design: A retrospective study of 1217 consecutive arbitrations.

Setting: A subset of discordant double readings from the Florence screening programme underwent arbitration by a third reader.

Results: Positive arbitration of 1217 discordant double readings prompted assessment in 476 cases (39.2%), detecting 30 cancers (6.3%). Of 741 negative arbitrations (60.8%), 311 have been followed up thus far, and two cancers (0.64%) occurred in the site previously suspected at one of the two independent readings. Arbitration had a sensitivity of 86.3% and a negative predictive value of 99.3%. Arbitration reduced the overall referral rates from 3.82% to 2.59% (relative decrease 32.1%). Due to false-negative arbitration, cancers detected per 1000 women screened would decrease from 4.58 to 4.50 (relative decrease 1.7%). For every cancer missed due to false-negative arbitration, 151 unnecessary recalls and €21,248 would have been saved, whereas the saved cost per screened woman due to arbitration was €1.72.

Discussion: Arbitration of discordant double reading would substantially reduce referral rates with a limited reduction in cancer detection rate, and may be recommended as a routine procedure. Greater benefit from arbitration might be expected in the presence of high referral rates at independent double reading, a common scenario in a newly implemented service screening.
Fostering interactions: the networking needs of community health nursing researchers and decision makers
Authors: Kothari Anita , Edwards Nancy , Brajtman Susan , Campbell Barbara , Hamel Nadia , Legault Frances , Mill Judy , Valaitis Ruta
Published: August 2005

English

The purpose of the study on which this article is based was to determine the current extent of linkages among Canadian community health nursing researchers and decision makers and to identify perceptions around the structure and function of potential networks. A qualitative research design was utilised to develop common themes across focus groups, a workshop and key informant interviews. The findings suggest that there is a need for a formal community health network to provide an efficient and timely means to link the expertise required to tackle complex community health policy problems, and to create supports for advancing community health science with relevant and high quality research.
Comparison of Spontaneous Raman and CARS Measurements in a Laminar Flame at Atmospheric Pressure
Authors: Kreutner W. , Stricker W. , Just Th.
Published: August 2005

Spontaneous Raman scattering and coherent anti-Stokes Raman scattering (CARS) were used to measure spatially resolved temperatures in a laminar, premixed propane/air flame at atmospheric pressure. Three models for the Raman linewidths were tested in the evaluation of the CARS spectra. Comparison with spontaneous Raman scattering shows that two of these models perform approximately equally; the third model leads to erroneous results.
The Mechanism of the Low-Temperature Oxidation of Coal by O2: Observation and Separation of Simultaneous Reactions Using In Situ FT-IR Difference Spectroscopy
Authors: Gethner Jon S.
Published: August 2005

Coal is complex, predominantly organic-containing porous solid which is important both as an energy and a chemical source material. The physical and chemical properties of most coals are extremely sensitive to air oxidation. There is no generally accepted mechanism for the oxidation process, in spite of past interest. Using in situ FT-IR difference spectroscopy of 0.4 μm thin sections of coal, we have examined the mechanism of the low-temperature oxidation of Illinois No. 6 bituminous coal by O2. The overall oxidation with O2 is found to be comprised of three separate chemical reactions. Two of the reactions involve O2 addition to reactive species in the coal. One is predominant at temperatures close to or slightly above room temperature and apparently involves the reversible binding of O2 to a free radical site, followed by reaction. The other oxidation is predominant by 100°C and proceeds by the formation and subsequent decomposition of hydroperoxides. The third reaction is a thermolysis which is important at temperatures between 25°C and 100°C and is competitive with the lower-temperature oxidation. It results in a partial decarbonylation and decarboxylation of the coal. Since three separate reactions contribute to the overall oxidation, the chemical and physical changes resulting from oxidation are dependent upon the oxidation conditions. Control of experimental conditions is critical in order for one to obtain reproducible results. Some of the possible implications of these results on the technologically important process of spontaneous ignition of coal are discussed. Results of previous oxidation studies are discussed in view of the present results. The large variations reported in oxidation studies are likely to be the consequence of ill-defined or poorly controlled experiments. We interpret the correlation between the present study and number of other studies to indicate that oxidation chemistry is the same in most coals, with the principal differences between coals being due to the different relative proportions of the reactive species in the starting coal.
Remote, Long-Pathlength Cell for High-Sensitivity Raman Spectroscopy
Authors: Schwab Scott D. , McCreery Richard L.
Published: August 2005

Fiber optics were used to interface a Raman spectrometer to a long (1 m) sample tube, with the objective being increased sensitivity. Internal reflection of the laser light and the Raman scatter within the sample tube permitted a long solution length to be sampled, increasing the Raman sensitivity by factors of 30–50 over conventional capillary tube sampling systems. In addition, the sample was subjected to much lower power densities than with systems employing a focused beam, thus minimizing radiation damage. Detection limits of 10−9 to 10−8 M were achieved for resonance Raman scatterers, and normal Raman scatterers could be detected at the 1 × 10−5 M level.
Calibration of the Radioisotope-Excited X-Ray Spectrometer with Thick Standards
Authors: Yap C. T. , Kump P. , Tang S. M. , Wijesinghe L.
Published: August 2005

Calibration of the energy-dispersive x-ray fluorescence spectrometer with Cd-109 annular excitation source is discussed. Experiments were performed to calibrate such a spectrometer using both thick standards and one type of commercially available, thin, single-element standard. It was found that the use of thick standards in such calibrations is reliable and accurate, in addition to being inexpensive and readily available.
Gaussian Band Shape Derived from Finite-Rate Oscillator Growth
Authors: Torkington P.
Published: August 2005

The accepted classical model for derivation of the frequency spectrum from the time-dependence of oscillator activity is considered. The exponential decay function giving rise to a Lorentzian band is modified to allow for a finite rate of growth of the oscillator, the resulting frequency spectrum is obtained, and the form normalized to unit band half-width is compared to the equivalent Lorentzian and Gaussian bands. It is shown that as the rate of oscillator growth decreases from infinity to one approximating the rate of decay, the resulting band contour changes from Lorentzian to near-Gaussian. At sufficiently fast growth-rates the band closely approximates a linear combination of Lorentzian and Gaussian.
Selenium and Mortality in the Elderly: Results from the EVA Study
Authors: Akbaraly N Tasnime , Arnaud Josiane , Hininger-Favier Isabelle , Gourlet Veronique , Roussel Anne-Marie , Berr Claudine
Published: August 2005

Background: Inadequate plasma selenium can adversely affect the maintenance of optimal health; therefore, reported decreases in plasma selenium in an aging population are cause for concern. To further examine this hypothesis, we explored the relationships between plasma selenium and mortality in an elderly population: the EVA (Etude du Vieillissement Artériel) study.

Methods: The EVA study was a 9-year longitudinal study with 6 periods of follow-up. During the 2-year period from 1991 to 1993 (EVA0), 1389 men and women born between 1922 and 1932 were recruited. The effects of plasma selenium at baseline on mortality were determined by Cox proportional hazards regression analysis, adjusting for the following variables: sociodemographic characteristics, dietary habits, health, and cognitive factors.

Results: During the 9-year follow-up, 101 study participants died. Baseline plasma selenium was higher in individuals who were alive at the end of follow-up [mean (SD), 1.10 (0.20) μmol/L] than in those who died during the follow-up [1.01 (0.20) μmol/L; P <10−4]. Mortality rates were significantly higher in individuals with low selenium [increments = 0.2 μmol/L; relative risk (RR) = 1.56 (95% confidence interval, 1.28–1.89)]. After we controlled for various potential confounding factors, this association remained significant [RR = 1.54 (1.25–1.88)]. When the underlying causes of death were considered, we found an association with cancer-related mortality [adjusted RR = 1.79 (1.32–2.44)].

Conclusions: Even if it is premature to present selenium as a longevity indicator in an elderly population, our results are in accordance those of large, interventional, randomized trials with selenium, which suggest that this essential trace element plays a role in health maintenance in aging individuals.
Theory and Practice Go Hand in Hand: A Tribute to Richard Johnson's Contributions to Marketing Research Methodology
Authors: Green Paul E.
Published: August 2005

This article is a response to Richard Johnson's (2005) memoir. It notes some of the important contributions that Johnson has made to marketing research and reflects on his unique personal and professional characteristics.
In Favor of Closer Ties
Authors: Johnson Richard M.
Published: August 2005

The author believes that marketing would be strengthened by closer relationships between academics and practitioners. He argues that the commercial market research environment can be stimulating for methodological development, and he suggests that everyone would benefit if academics and practitioners had experience in both environments.
Direct-to-Consumer Advertising and Drug Therapy Compliance
Authors: Wosinska Marta
Published: August 2005

Because of their arm's-length relationship with patients, pharmaceutical manufacturers have been interested in whether drug advertising can improve therapy compliance. Contrary to many industry surveys, the author finds that the impact is small in economic terms, the effect spills over to other brands, and, in certain cases, the effect may decrease average compliance rates.
Estimating a Stockkeeping-Unit-Level Brand Choice Model that Combines Household Panel Data and Store Data
Authors: Chintagunta Pradeep K. , Dubé Jean-Pierre
Published: August 2005

The marketing literature has addressed the issues of heterogeneity and endogeneity when estimating a choice model with household-level panel data. When using these data at the stockkeeping unit or the Universal Product Code level, choices for each item in each of the time periods under consideration cannot be observed. Without such information, it is difficult to control for item- and time period–specific unmeasured characteristics because there is no information on alternatives during those periods in which they are not purchased by any of the panelists. In general, when a product category has many alternatives, each with fairly small shares, the household sample may not contain sufficient choices for each alternative, thus negatively affecting the ability to control for endogeneity with household data. In contrast, because aggregate store-level data (for those stores in which the panel makes purchases) are the aggregation of purchases by all households visiting the stores, the data contain the time period–specific item-level information required to account for endogeneity as long as each item has some sales in each time period. Given the relative merits of household data to estimate the distribution of heterogeneity and store-level data to address the endogeneity problem, the authors propose an integrated estimation procedure that uses the information in both sources. They provide empirical results from their model using data on the fabric softener market. They extend their approach to situations in which there is variation in purchase quantities that households choose.
Borderline Personality Disorder and Deliberate Self‐Harm: Does Experiential Avoidance Play a Role?
Authors: Chapman Alexander L. , Specht Matthew W. , Cellucci Tony
Published: August 2005

The theory that borderline personality disorder (BPD) is associated with experiential avoidance, and that experiential avoidance mediates the association between BPD and deliberate, nonsuicidal self‐harm was examined. Female inmate participants (N = 105) were given structured diagnostic assessments of BPD, as well as several measures of experiential avoidance. There was a high lifetime prevalence of past self‐harm (47.6%). Higher dimensional scores representing BPD severity were associated with higher self‐harm frequency and greater experiential avoidance. Structural equation modeling analyses indicated that experiential avoidance did not mediate the association between BPD and self‐harm, although thought suppression was associated with self‐harm frequency.
Social Risk and Protective Factors for Suicide Attempts in Low Income African American Men and Women
Authors: Kaslow Nadine J. , Sherry Alissa , Bethea Kafi , Wyckoff Sarah , Compton Michael T. , Grall Marnette Bender , Scholl Larry , Price Ann Webb , Kellermann Arthur , Thompson Nancy , Parker Ruth
Published: August 2005

A case‐control study was conducted to examine a broad array of potential social risk and protective factors for suicide attempt among 200 African American men and women receiving care at a large, public, urban hospital. Specifically, we examined the effect of the following potential risk factors for suicide attempt: life hassles, partner abuse, partner dissatisfaction, and racist events; as well as the following potential protective factors: effectiveness of obtaining resources, social embeddedness, and social support. Using logistic regression, suicide attempter status was predicted by two independently significant social variables: one risk factor (life hassles) and one protective factor (social support). Male versus female suicide attempters were not distinguished by the social variables. These findings, which support the utility of an ecological conceptualization of risk and protective factors for suicide attempt, help to clarify the independently significant social environment risk and protective factors for suicide attempts among economically disadvantaged African Americans in particular. Research on both risk factors and protective factors provide a basis for culturally competent interventions aimed at reducing both the risk of future suicide attempts and completions.
Adolescent Suicidality: Who Will Ideate, Who Will Act?
Authors: Miller Ted R. , Taylor Dexter M.
Published: August 2005

Responses to the 1999 Youth Risk Behavior Survey including suicide ideation, attempt, medically treated attempt, and six problem behaviors were analyzed. Youth across the spectrum ideated. Overwhelmingly, the 17% of youth with more than three problem behaviors were the youth who acted; they accounted for 60% of medically treated suicidal acts. Compared to adolescents with zero problem behaviors, the odds of a medically treated suicide attempt were 2.3 times greater among respondents with one, 8.8 with two, 18.3 with three, 30.8 with four, 50.0 with five, and 227.3 with six. A count of problem behaviors offers a reliable way to identify suicide risk.
Securing a Suicide Hot Spot: Effects of a Safety Net at the Bern Muenster Terrace
Authors: Reisch Thomas , Michel Konrad
Published: August 2005

The city of Bern has a high percentage of suicides by jumping (28.6%). Related to other local hotspots, the highest number of deaths (mean 2.5 per year) is found at the Muenster Terrace in the old city. In 1998, after a series of suicides, a safety net was built to prevent people from leaping from the terrace and to avoid further traumatization of people living in the street below. We analyzed the numbers of suicides by jumping before and after the installation of the net. We also assessed the number of media reports referring to this suicide method. After the installation of the net no suicides occurred from the terrace. The number of people jumping from all high places in Bern was significantly lower compared to the years before, indicating that no immediate shift to other nearby jumping sites took place. Furthermore, we found a moderate correlation between the number of media reports and the number of persons resident outside Bern committing suicide by jumping from high places in the city.
Psychological Factors in Deliberate Self‐Harm As Seen in an Urban African Population in Uganda: A Case‐Control Study
Authors: Kinyanda Eugene , Hjelmeland Heidi , Musisi Seggane
Published: August 2005

Psychological factors associated with deliberate self‐harm (DSH) as seen in an African population in Uganda are described. A case‐control study design was employed in which a Luganda version (predominant language in the study area) of the modified European Parasuicide Interview Schedule I (EPSIS I) was used to collect data. The controls were patients admitted to the participating hospitals for non‐recurrent medical conditions. Hopelessness, global psychological distress, and state anger, but not depression, were significantly associated with DSH after controlling for other factors. Both depression and hopelessness were significantly associated with suicidal intent independent of each other. Differences were observed on the psychological factors associated with suicidal intent in the different age/sex groups and in the depressed/nondepressed group. Interventions for DSH in this population should include treatments for both depression and hopelessness. This study further raises questions about the universality of the structural relationship among depression, hopelessness, and suicidality.
Industrielle Sauerstoffmessung mit einem neuartigen oberflächenemittierenden Laser (Oxygen Measurements by Using a Novel Vertical-Cavity Surface-Emitting Laser)
Authors: Wöllenstein Jürgen , Braun Marcus , Hartwig Susanne , Lambrecht Armin , Peter Andreas , Ostermann Johannes Michael , Rinaldi Fernando , Michalzik Rainer
Published: August 2005

Oberflächenemittierende Halbleiterlaser (VCSEL) werden zur spektroskopischen Sauerstoffmessung im Wellenlängenbereich bei 762 nm eingesetzt. Hierfür wurden besonders polarisationsstabile Laserdioden auf der Basis von AlGaAs entwickelt. Im Vergleich zu kantenemittierenden Lasern lassen sich VCSELs deutlich besser über den Betriebsstrom abstimmen, während sich die Temperaturmodulation in der gleichen Größenordnung bewegt. Bei dem konventionellen Verfahren der Abstimmung über Stromrampen wurde 1 kHz als Messfrequenz gewählt. Weiterhin wurde der Einsatz besonders schneller Peltierelemente für die schnelle Abstimmung durch Temperaturrampen über mehrere Gasabsorptionslinien gezeigt.
Schnelles Infrarot-Laserspektrometer DEGAS für die Abgasmessung am Motorprüfstand – Ergebnisse und Perspektiven (Dynamic Exhaust Gas Analysis for Test Bed Application Using Infrared Laser Spectroscopy – Results and Outlook)
Authors: Sassenscheid Karsten
Published: August 2005

Vor dem Hintergrund der weltweit verschärften Abgasvorschriften für Kraftfahrzeuge benötigt die Automobilindustrie innovative Messtechniken, die zugleich eine empfindliche, selektive und zeitlich hochaufgelöste Multikomponentenanalyse des Abgases ermöglichen. Das neuartige Abgasmess system DEGAS IV, das am Fraunhofer Institut für Physikalische Messtechnik in Freiburg (IPM) entwickelt wurde, erlaubt es, die Konzentration verschiedener Abgaskomponenten gleichzeitig zu bestimmen. Dies ist zeitaufgelöst bis in den Bereich eines einzelnen Motortakts möglich. Dadurch lassen sich sowohl Motormanagement als auch Abgasnachbehandlung entscheidend optimieren.
Neue kristalline Piezoaktoren für die industrielle Messtechnik (New Crystalline Piezo Actuators for Industrial Measurement Applications)
Authors: Hinkov Vladimir , Körber Markus
Published: August 2005

Es wurden neuartige monokristalline Piezoaktoren, die für die industrielle Messtechnik besonders gut geeignet sind, entwickelt und untersucht. Der vorliegende Beitrag zeigt, wie die Herstellungstechnologie der thermischen Domäneninversion optimiert wurde, wobei noch ein relativ großer Spielraum zur Verbesserung dieser Technologie und somit zur Steigerung der Leistungsfähigkeit der neuen Aktoren besteht. Darüber hinaus haben die Untersuchungen der Wandler folgende Eigenschaften gezeigt: hohe Linearität, extrem kleine Hysterese im Bereich von Promille der maximalen Ablenkung, Ermöglichung von Torsionsbewegungen mit hoher Bandbreite (3 kHz), sehr gute Temperaturstabilität und eine sehr große Auflösung beim Einsatz als Laserstrahlablenker.
Expression of somatostatin receptor subtypes 1–5 in pancreatic islets of normoglycaemic and diabetic NOD mice
Authors: Ludvigsen E , Stridsberg M , Janson E T , Sandler S
Published: August 2005

Objective: Somatostatin acts on five specific receptors (sst1–5) to elicit different biological functions. The non-obese diabetic (NOD) mouse is an experimental model of type 1 diabetes. The aim of this study was to investigate whether the islet expression of sst1–5 is affected during the development of diabetes in NOD mice, with insulitis accompanied by spontaneous hyperglycaemia.

Methods: By immunostaining for sst1–5 the expression and co-expression together with the four major islet hormones in pancreatic islets were investigated in female and male NOD mice at different stages of disease. The NOD related non-diabetic ICR mouse was also examined.

Results: The islet cells of diabetic NOD mice showed an increased islet cell expression of sst2–5 compared with normoglycaemic female NOD mice. This correlated to increasing age and extent of insulitis. Major findings from the co-expression investigations were that sst2 was expressed in a majority of β-cells in the normoglycaemic NOD mice, but absent in the β-cells in the diabetic NOD mice. A majority of the α-cells expressed sst2 and 5 in normoglycaemic and diabetic NOD mice. About 60% of δ-cells showed co-expression of sst4 and 5 in both normoglycaemic and diabetic NOD mice. 60% of pancreatic polypeptide (PP)-cells expressed sst4 in both groups. Insulitis was found to be accompanied by a down-regulation of sst in normoglycaemic animals.

Conclusions: The difference in sst expression in the islets cells of diabetic mice may suggest either a contributing factor in the process leading to diabetes, or a defence response against ongoing β-cell destruction.
Central administration of resistin promotes short-term satiety in rats
Authors: Tovar Sulay , Nogueiras Rubén , Tung Loraine Y C , Castañeda Tamara R , Vázquez María Jesús , Morris Amanda , Williams Lynda M , Dickson Suzanne L , Diéguez Carlos
Published: August 2005

Objective: Several hormones expressed in white adipose tissue influence food intake at the central level. We sought to determine whether resistin, a circulating adipose-derived hormone in rodents, has actions on the hypothalamus by determining the effects of central resistin injection on food intake and on hypothalamic Fos protein expression.

Design: As resistin expression in adipose tissue is influenced by altered nutritional status, we studied the effect of central resistin in both fed and pre-fasted rats.

Results: In fasted rats, central injection of resistin decreased food intake acutely and increased the number of cells that express Fos protein in the arcuate nucleus but not in any other hypothalamic structure. The effect on food intake was dose-dependent and did not result in the formation of a conditioned taste aversion.

Conclusions: Taken together, these results provide the first evidence documenting a central action of resistin, which could be involved in a feedback loop targeting the hypothalamus. On the other hand, since we observed resistin mRNA in the arcuate and ventromedial nuclei of the hypothalamus, it is also possible that brain-derived resistin serves as a neuropeptide involved in the regulation of energy homeostasis. However, since resistin-induced satiety was modest and transient, as central administration for several days did not affect body weight, the physiological relevance and therapeutic potential of the observed principal phenomenon may be limited.
Embryonic Stem Cell-Derived Neural Progenitors Incorporate into Degenerating Retina and Enhance Survival of Host Photoreceptors
Authors: Meyer Jason S. , Katz Martin L. , Maruniak Joel A. , Kirk Mark D.
Published: August 2005

Embryonic stem (ES) cells differentiate into all cell types of the body during development, including those of the central nervous system (CNS). After transplantation, stem cells have the potential to replace host cells lost due to injury or disease or to supply host tissues with therapeutic factors and thus provide a functional benefit. In the current study, we assessed whether mouse neuralized ES cells can incorporate into retinal tissue and prevent retinal degeneration in mnd mice. These mice have an inherited lysosomal storage disease characterized by retinal and CNS degeneration. Sixteen weeks after intravitreal transplantation into adult mice, donor cells had incorporated into most layers of the retina, where they resembled retinal neurons in terms of morphology, location in the retina, and expression of cell type–specific marker proteins. Presence of these donor cells was correlated with a reduction in the sizes and numbers of lysosomal storage bodies in host retinal cells. The presence of transplanted donor cells was also accompanied by enhanced survival of host retinal neurons, particularly photoreceptors. These results demonstrate that neuralized ES cells protect host neurons from degeneration and appear to replace at least some types of lost neurons.
Small Peptide Analogue of SDF-1α Supports Survival of Cord Blood CD34+ Cells in Synergy with Other Cytokines and Enhances Their Ex Vivo Expansion and Engraftment into Nonobese Diabetic/Severe Combined Immunodeficient Mice
Authors: Li Karen , Chuen Carmen Ka Yee , Lee Shuk Man , Law Ping , Fok Tai Fai , Ng Pak Cheung , Li Chi Kong , Wong Donald , Merzouk Ahmed , Salari Hassan , Gu Goldie Jia-Shi , Yuen Patrick Man Pan
Published: August 2005

The SDF-1/CXCR4 axis has been implicated in the chemotaxis, homing, mobilization, and expansion of hematopoietic stem and progenitor cells. We studied the effects of a SDF-1 peptide analogue CTCE-0214 on the survival of cord blood CD34+ cells in culture, expansion, and engraftment of expanded cells in the nonobese diabetic/severe combined immunodeficient (NOD/SCID) mouse model. Our results demonstrated that CTCE-0214 synergized with thrombopoietin (TPO), stem cell factor (SCF), or flt-3 ligand (FL) on the survival of stem and progenitor cells in culture. Adding CTCE-0214 at a low concentration (0.01 ng/ml) for 4 days together with TPO, SCF, and FL significantly enhanced ex vivo expansion of CD34+ cells to subsets of primitive (CD34+CD38− cells, colony-forming unit-mixed [CFU-GEMMs]), erythroid (CFU-Es), myeloid (CFU-GMs), and megakaryocytic (CD61+CD41+ cells, CFU-MKs) progenitors, as well as their multilineage engraftment in NOD/SCID mice. Interestingly, the short exposure of expanded cells to CTCE-0214 (100 and 500 ng/ml) for 4 hours did not increase the quantity of progenitor cells but enhanced their engraftment capacity. The proportion of CD34+ cells expressing surface CXCR4 was decreased, but the overall number of this population increased upon expansion. The small peptide analogue of SDF-1 could be developed for ex vivo expansion and improving engraftment of cord blood transplantation.
Cell Size Correlates with Phenotype and Proliferative Capacity in Human Corneal Epithelial Cells
Authors: De Paiva Cintia S. , Pflugfelder Stephen C. , Li De-Quan
Published: August 2005

This study investigated whether cell size correlates with phenotype and proliferative capacity in human corneal epithelial cells. Primary cultured human corneal epithelial cells were sorted by flow cytometry based on forward scatter profile in comparison with the profile of beads of known size. Four fractions (A, B, C, and D) of cells ranging in size from 10 to 16, 17 to 23, 24 to 30, and ≥31 μm in diameter, respectively, were collected to evaluate their 5-bromo-2-deoxyuridine (BrdU) label retention properties, cell phenotype, and clonal growth capacity on a 3T3 fibroblast feeder layer. Among these four populations, cell size was shown to positively correlate with the expression of the differentiation markers keratin (K) 3, K12, and involucrin and inversely with the levels of stem cell–associated markers ΔNp63 and ABCG2 and with colony-forming efficiency (CFE) and growth capacity. Population A with the smallest size, accounting for 11.0% ± 4.5% of the entire population, contained the greatest number of BrdU label-retaining slow-cycling cells, displayed the highest percentage of cells immunopositive to p63 and ABCG2 and negative to K3 and involucrin, expressed the highest levels of ΔNp63 and ABCG2 mRNA and the lowest levels of K3, K12, and involucrin, and possessed the highest CFE and growth capacity. These findings suggest that cell size correlates with cell differentiation phenotypes and proliferative capacity in human corneal epithelial cells. The smallest cells in population A seem to be enriched for putative stem cells, and small cell size may represent one of the important properties of adult corneal epithelial stem cells.
Absence of Suppressor of Cytokine Signalling 3 Reduces Self-Renewal and Promotes Differentiation in Murine Embryonic Stem Cells
Authors: Forrai Ariel , Boyle Kristy , Hart Adam H. , Hartley Lynne , Rakar Steven , Willson Tracy A. , Simpson Ken M. , Roberts Andrew W. , Alexander Warren S. , Voss Anne K. , Robb Lorraine
Published: August 2005

Leukemia inhibitory factor (LIF) is required to maintain pluripotency and permit self-renewal of murine embryonic stem (ES) cells. LIF binds to a receptor complex of LIFR-β and gp130 and signals via the Janus kinase–signal transducer and activator of transcription (JAK–STAT) pathway, with signalling attenuated by suppressor of cytokine signalling (SOCS) proteins. Recent in vivo studies have highlighted the role of SOCS-3 in the negative regulation of signalling via gp130. To determine the role of SOCS-3 in ES cell biology, SOCS-3–null ES cell lines were generated. When cultured in LIF levels that sustain self-renewal of wild-type cells, SOCS-3–null ES cell lines exhibited less self-renewal and greater differentiation into primitive endoderm. The absence of SOCS-3 enhanced JAK–STAT and extracellular signal–related kinase 1/2 (ERK-1/2)–mitogen-activated protein kinase (MAPK) signal transduction via gp130, with higher levels of phosphorylated STAT-1, STAT-3, SH-2 domain–containing cytoplasmic protein tyrosine phosphatase 2 (SHP-2), and ERK-1/2 in steady state and in response to LIF stimulation. Attenuation of ERK signalling by the addition of MAPK/ERK kinase (MEK) inhibitors to SOCS-3–null ES cell cultures rescued the differentiation phenotype, but did not restore proliferation to wild-type levels. In summary, SOCS-3 plays a crucial role in the regulation of the LIF signalling pathway in murine ES cells. Its absence perturbs the balance between activation of the JAK–STAT and SHP-2–ERK-1/2–MAPK pathways, resulting in less self-renewal and a greater potential for differentiation into the primitive endoderm lineage.
Bond between ribbed bars and concrete. Part 1: Modified model
Authors: Lundgren K.
Published: August 2005

The bond between ribbed bars and concrete is influenced by a number of parameters, such as the strength of the surrounding structure, the occurrence of splitting cracks, and yielding of the reinforcement. A model for three-dimensional analyses was developed earlier by the author, where the splitting stresses of the bond action were included, and the bond stress depended not only on the slip but also on the radial deformation between the reinforcement bar and the concrete. The bond model, however, was shown to generate energy for some special loading–unloading sequences. This undesirable effect has led to a change in the formulation of the bond model. With the modification as described here, the model becomes equivalent to the Coulomb friction, complemented with a yield function describing the upper limit. Pull-out tests were analysed, using the modified bond model and nonlinear fracture mechanics for the concrete. The tests were selected to show various types of failure: pull-out failure, splitting failure, pull-out failure after yielding of the reinforcement, rupture of the reinforcement bar, and cyclic loading. The results show that the modified model is capable of predicting splitting failures, and the loss of bond if the reinforcement is yielding, as well as simulating cyclic loading in a physically reasonable way.
Bond between ribbed bars and concrete. Part 2: The effect of corrosion
Authors: Lundgren K.
Published: August 2005

The corrosion products that form when reinforcement in concrete corrodes occupy a larger volume than the steel it was formed of, thus leading to splitting stresses acting on the concrete. Thereby, the bond between the reinforcement and the concrete is influenced. A model of the corrosion was developed by the author in earlier work. This was used together with a modified model of the bond mechanism, presented in a companion paper, in three-dimensional finite element analyses where both the reinforcement and the concrete were modelled with solid elements. Several corrosion cracking tests, beams and pull-out tests with corroded reinforcement, both with and without transverse reinforcement, carried out by various researchers, were analysed by using the corrosion model. The results were compared, and reasonably good agreement was found. Furthermore, the model was used to study the effect of uniform or localised corrosion. It was shown that for localised corrosion, less average corrosion penetration was needed to crack the cover than for uniform corrosion; in addition, the crack pattern differed. From these analyses, it was concluded that axisymmetric analyses appear to be a sufficient level of modelling when studying cracking due to uniform corrosion. If localised corrosion is to be studied, three-dimensional models need to be used. The model was also used to study the effect of uniform corrosion on the anchorage length when no transverse reinforcement is present. Under these circumstances, the criterion ‘the anchorage of the reinforcement becomes critical when cracking of the cover occurs’ was shown to be on the safe side to use.
CARDIFRC® – Development and mechanical properties. Part II: Fibre distribution
Authors: Benson S. D. P. , Nicolaides D. , Karihaloo B. L.
Published: August 2005

Part II of this three-part paper deals with the assessment of the distribution of fibres in CARDIFRC®, a class of high-performance short steel fibre-reinforced cementitious composites. The effect of the mixing procedure and of the shape of the object cast from CARDIFRC® on the distribution of the fibres is assessed using both a nondestructive and a destructive technique. The non-destructive technique is based on computerised tomography imaging and the destructive technique on image analysis.
Soil Organic Carbon Pools After 12 Years in No‐Till Dryland Agroecosystems
Authors: Sherrod L. A. , Peterson G. A. , Westfall D. G. , Ahuja L. R.
Published: August 2005

Previous studies of no‐till management in the Great Plains have shown that increased cropping intensity increased soil organic carbon (SOC). The objectives of this study were to (i) determine which soil C pools (active, slow, and passive) were impacted by cropping intensity after 12 yr of no‐till across potential evapotranspiration (PET) and slope position gradients; (ii) relate C pool sizes to the levels found in total SOC; and (iii) determine C pool sizes relative to C levels found in a grass treatment (G). Cropping systems were wheat (Triticum aestivum)‐fallow (WF), wheat‐corn (Zea maysL.)‐fallow (WCF), wheat‐corn‐millet (Panicum miliaceum)‐fallow (WCMF), and continuous cropping (CC) at three PET sites in Colorado. Active C (Soil microbial biomass C [SMBC]); and slow pool C (particulate organic matter C; POM‐C) increased as cropping intensity increased, dependent on PET. Passive C (mineral associated organic C [MAOC]) was strongly influenced by a site‐by‐slope position interaction but not by cropping system. Toeslope soils had 35% higher POM‐C compared with summits and sideslopes. All C pools were strongly correlated with total SOC, with the variability decreasing as C pool turnover time increased. Carbon pool sizes in cropping systems relative to levels found in G were independently influenced by cropping system. The highest were found in the CC system, which had 91, 78, and 90% of the amounts of C found in the perennial G system in the active, slow, and passive C pools, respectively.
Prediction of Soil Organic Carbon across Different Land‐use Patterns
Authors: Somaratne S. , Seneviratne G. , Coomaraswamy U.
Published: August 2005

Mathematical modeling has widely been used to predict soil organic carbon (SOC). However, there are characteristics of the models such as over simplification, ignorance of complex nonlinear interactions etc., which limit their use in accurately assessing the distribution of the C across the landscapes. Artificial neural network (ANN) modeling approach that provides a tool to solve complex problems related to larger data sets was therefore used here to predict SOC contents across different land use patterns in a study conducted in Sri Lanka. Selection of variables was made using a priori knowledge of the relationships between the variables. Thus, soils of the sites were sampled and analyzed for organic C by internal heat of dilution (Ci) and external heat of dilution (Ce), and the results were presented as grams per kilogram (g kg−1). In addition, some landscape attributes and environmental parameters of the sites were also collected. The predictive performance of ANN was compared with multi‐linear regression (MLR) models. The best ANN model predicted the measured Ci content with R2 of 0.92. However, comparison of the two types of models indicated less bias and high accuracy of the ANN compared with MLR in predicting Ci, but the reverse for Ce. In order to better predict Ce, it is recommended to use other architectures of neural networks and training algorithms for improving predictive accuracy. The predictive capability of the ANN developed with easily available climatic and terrain data are of importance in predicting SOC with minimum cost, labor, and time.
Rhizosphere Effects on Cesium Fixation Sites of Soil Containing Micaceous Clays
Authors: Wendling Laura A. , Harsh James B. , Palmer Carl D. , Hamilton Melinda A. , Dion Heather M. , Boyle Jeffrey S. , Flury Markus
Published: August 2005

Physical and chemical weathering processes in the rhizosphere may lead to the generation of a greater density of Cs‐selective frayed edge sites (FES) on rhizosphere soil as compared with bulk soil. This study was undertaken to determine if there are significant differences between bulk and rhizosphere soils from the Idaho National Laboratory (INL) with respect to their ability to bind Cs. The capacity of FES on bulk and rhizosphere soil materials and conditional Cs/K selectivity of FEScKexFESwere determined as a function of both soil type and initial exchanger composition. The FES capacity was significantly higher in untreated, Ca‐saturated, and K‐saturated rhizosphere soil materials as compared with bulk soil materials. Sorption–desorption isotherms were obtained at Cs concentrations between 5 × 10−9and 5 × 10−6MNo difference in Cs sorption was observed between bulk and rhizosphere soil materials. The composition of the exchanging solution had the greatest effect on the magnitude of Cs desorption; significantly more Cs was desorbed in the presence of KCl than in either CaCl2or a mixed‐cation soil solution. In addition, Cs desorption was greater from rhizosphere soil materials relative to bulk soil materials. Cesium selectivity with respect to both Ca and K was significantly suppressed by weathering in the rhizosphere. We conclude that enhanced weathering in the rhizosphere increased the Cs sorption capacity of FES, but also reduced Cs selectivity on these sites. Enhanced Cs desorption from rhizosphere INL soils is likely in the presence of actively growing plants and associated microorganisms.