bluuebunny/crossref_metadata_2025 huggingface dataset:
Study protocol: The Improving Care of Acute Lung Injury Patients (ICAP) study
Authors: Needham Dale M , Dennison Cheryl R , Dowdy David W , Mendez-Tellez Pedro A , Ciesla Nancy , Desai Sanjay V , Sevransky Jonathan , Shanholtz Carl , Scharfstein Daniel , Herridge Margaret S , Pronovost Peter J
Published: December 2005

Introduction

The short-term mortality benefit of lower tidal volume ventilation (LTVV) for patients with acute lung injury/acute respiratory distress syndrome (ALI/ARDS) has been demonstrated in a large, multi-center randomized trial. However, the impact of LTVV and other critical care therapies on the longer-term outcomes of ALI/ARDS survivors remains uncertain. The Improving Care of ALI Patients (ICAP) study is a multi-site, prospective cohort study that aims to evaluate the longer-term outcomes of ALI/ARDS survivors with a particular focus on the effect of LTVV and other critical care therapies.

Methods

Consecutive mechanically ventilated ALI/ARDS patients from 11 intensive care units (ICUs) at four hospitals in the city of Baltimore, MD, USA, will be enrolled in a prospective cohort study. Exposures (patient-based, clinical management, and ICU organizational) will be comprehensively collected both at baseline and throughout patients' ICU stay. Outcomes, including mortality, organ impairment, functional status, and quality of life, will be assessed with the use of standardized surveys and testing at 3, 6, 12, and 24 months after ALI/ARDS diagnosis. A multi-faceted retention strategy will be used to minimize participant loss to follow-up.

Results

On the basis of the historical incidence of ALI/ARDS at the study sites, we expect to enroll 520 patients over two years. This projected sample size is more than double that of any published study of long-term outcomes in ALI/ARDS survivors, providing 86% power to detect a relative mortality hazard of 0.70 in patients receiving higher versus lower exposure to LTVV. The projected sample size also provides sufficient power to evaluate the association between a variety of other exposure and outcome variables, including quality of life.

Conclusion

The ICAP study is a novel, prospective cohort study that will build on previous critical care research to improve our understanding of the longer-term impact of ALI/ARDS, LTVV and other aspects of critical care management. Given the paucity of information about the impact of interventions on long-term outcomes for survivors of critical illness, this study can provide important information to inform clinical practice.
The expression signature of in vitro senescence resembles mouse but not human aging
Authors: Wennmalm Kristian , Wahlestedt Claes , Larsson Ola
Published: December 2005

Background

The biological mechanisms that underlie aging have not yet been fully identified. Senescence, a phenomenon occurring in vitro, limits the number of cell divisions in mammalian cell cultures and has been suggested to contribute to aging.

Results

We investigated whether the changes in gene expression that occur during mammalian aging and induction of cellular senescence are similar. We compared changes of gene expression in seven microarray datasets from aging human, mouse and rat, as well as four microarray datasets from senescent cells of man and mouse. The datasets were publicly available or obtained from other laboratories. Correlation measures were used to establish similarities of the expression profiles and gene ontology analyses to identify functional groups of genes that are co-regulated. Robust similarities were established between aging in different species and tissues, indicating that there is an aging transcriptome. Although some cross-species comparisons displayed high correlation, intra-species similarities were more reliable. Similarly, a senescence transcriptome was demonstrated that is conserved across cell types. A similarity between the expression signatures of cellular senescence and aging could be established in mouse, but not in human.

Conclusion

Our study is the first to use microarray data from several studies and laboratories for dissection of a complex biological phenotype. We demonstrate the presence of a mammalian aging transcriptome, and discuss why similarity between cellular senescence and aging is apparent in aging mice only.
Somatostatin Inhibits Oxidative Respiration in Pancreatic β-Cells
Authors: Daunt Mathew , Dale Oliver , Smith Paul A.
Published: December 2005

Somatostatin potently inhibits insulin secretion from pancreatic β-cells. It does so via activation of ATP-sensitive K+-channels (KATP) and G protein-regulated inwardly rectifying K+-channels, which act to decrease voltage-gated Ca2+-influx, a process central to exocytosis. Because KATP channels, and indeed insulin secretion, is controlled by glucose oxidation, we investigated whether somatostatin inhibits insulin secretion by direct effects on glucose metabolism. Oxidative metabolism in β-cells was monitored by measuring changes in the O2 consumption (ΔO2) of isolated mouse islets and MIN6 cells, a murine-derived β-cell line. In both models, glucose-stimulated ΔO2, an effect closely associated with inhibition of KATP channel activity and induction of electrical activity (r > 0.98). At 100 nm, somatostatin abolished glucose-stimulated ΔO2 in mouse islets (n = 5, P < 0.05) and inhibited it by 80 ± 28% (n = 17, P < 0.01) in MIN6 cells. Removal of extracellular Ca2+, 5 mm Co2+, or 20 μm nifedipine, conditions that inhibit voltage-gated Ca2+ influx, did not mimic but either blocked or reduced the effect of the peptide on ΔO2. The nutrient secretagogues, methylpyruvate (10 mm) and α-ketoisocaproate (20 mm), also stimulated ΔO2, but this was unaffected by somatostatin. Somatostatin also reversed glucose-induced hyperpolarization of the mitochondrial membrane potential monitored using rhodamine-123. Application of somatostatin receptor selective agonists demonstrated that the peptide worked through activation of the type 5 somatostatin receptor. In conclusion, somatostatin inhibits glucose metabolism in murine β-cells by an unidentified Ca2+-dependent mechanism. This represents a new signaling pathway by which somatostatin can inhibit cellular functions regulated by glucose metabolism.
Mechanisms Underlying the Diminished Sensitivity to Prolactin Negative Feedback during Lactation: Reduced STAT5 Signaling and Up-Regulation of Cytokine-Inducible SH2 Domain-Containing Protein (CIS) Expression in Tuberoinfundibular Dopaminergic Neurons
Authors: Anderson Stephen T. , Barclay Johanna L. , Fanning Kent J. , Kusters Daphne H. L. , Waters Michael J. , Curlewis Jon D.
Published: December 2005

Hyperprolactinaemia during lactation is a consequence of the sucking stimulus and in part due to reduced prolactin (PRL) negative feedback. To date, the mechanisms involved in this diminished sensitivity to PRL feedback are unknown but may involve changes in PRL signal transduction within tuberoinfundibular dopaminergic (TIDA) neurons. Therefore, we investigated signal transducers and activators of transcription (STAT) 5 signaling in the TIDA neurons of lactating rats. Dual-label confocal immunofluorescence studies were used to determine the intracellular distribution of STAT5 within TIDA neurons in the dorsomedial arcuate nucleus. In lactating rats with pups removed for 16 h, injection of ovine PRL significantly (P < 0.05) increased the STAT5 nuclear/cytoplasmic ratio compared with vehicle-treated mothers. In contrast, ovine PRL injection did not increase the STAT5 nuclear/cytoplasmic ratio in lactating mothers with pups, demonstrating that PRL signal transduction through STAT5 is reduced in TIDA neurons in the presence of pups. To investigate possible mechanisms involved in reduced PRL signaling, we examined the expression of suppressors of cytokine signaling (SOCS) proteins. Northern analysis on whole hypothalamus showed that CIS (cytokine-inducible SH2 domain-containing protein), but not SOCS1 or SOCS3, mRNA expression was significantly (P < 0.01) up-regulated in suckled lactating rats. Semiquantitative RT-PCR on arcuate nucleus micropunches also showed up-regulation of CIS transcripts. Immunofluorescence studies demonstrated that CIS is expressed in all TIDA neurons in the dorsomedial arcuate nucleus, and the intensity of CIS staining in these neurons is significantly (P < 0.05) increased in lactating rats with sucking pups. Together, these results support the hypothesis that loss of sensitivity to PRL-negative feedback during lactation is a result of increased CIS expression in TIDA neurons.
Peroxisome Proliferator-Activated Receptor α Mediates the Effects of High-Fat Diet on Hepatic Gene Expression
Authors: Patsouris David , Reddy Janardan K. , Müller Michael , Kersten Sander
Published: December 2005

Peroxisome proliferator-activated receptors (PPARs) are transcription factors involved in the regulation of numerous metabolic processes. The PPARα isotype is abundant in liver and activated by fasting. However, it is not very clear what other nutritional conditions activate PPARα. To examine whether PPARα mediates the effects of chronic high-fat feeding, wild-type and PPARα null mice were fed a low-fat diet (LFD) or high-fat diet (HFD) for 26 wk. HFD and PPARα deletion independently increased liver triglycerides. Furthermore, in wild-type mice HFD was associated with a significant increase in hepatic PPARα mRNA and plasma free fatty acids, leading to a PPARα-dependent increase in expression of PPARα marker genes CYP4A10 and CYP4A14. Microarray analysis revealed that HFD increased hepatic expression of characteristic PPARα target genes involved in fatty acid oxidation in a PPARα-dependent manner, although to a lesser extent than fasting or Wy14643. Microarray analysis also indicated functional compensation for PPARα in PPARα null mice. Remarkably, in PPARα null mice on HFD, PPARγ mRNA was 20-fold elevated compared with wild-type mice fed a LFD, reaching expression levels of PPARα in normal mice. Adenoviral overexpression of PPARγ in liver indicated that PPARγ can up-regulate genes involved in lipo/adipogenesis but also characteristic PPARα targets involved in fatty acid oxidation. It is concluded that 1) PPARα and PPARα-signaling are activated in liver by chronic high-fat feeding; and 2) PPARγ may compensate for PPARα in PPARα null mice on HFD.
Energy Expenditure and Body Composition of Chronically Maintained Decerebrate Rats in the Fed and Fasted Condition
Authors: Harris Ruth B. S. , Kelso Emily W. , Flatt William P. , Bartness Timothy J. , Grill Harvey J.
Published: December 2005

The contribution of the caudal brainstem to adaptation to starvation was tested using chronically maintained decerebrate (CD) and neurologically intact controls. All rats were gavage fed an amount of diet that maintained weight gain in controls. CD rats were subjected to a two-stage surgery to produce a complete transection of the neuroaxis at the mesodiencephalic juncture. One week later, the rats were housed in an indirect calorimeter, and 24 h energy expenditure was measured for 4 d. One half of each of the CD and control groups was then starved for 48 h. Fed CD rats maintained a lower body temperature (35 C), a similar energy expenditure per unit fat-free mass but an elevated respiratory quotient compared with controls. They gained less weight, had 20% less lean tissue, and had 60% more fat than controls. Circulating leptin, adiponectin, and insulin were elevated, glucose was normal, but testosterone was dramatically reduced. Responses to starvation were similar in CD and controls; they reduced energy expenditure, decreased respiratory quotient, indicating lipid utilization, defended body temperature, mobilized fat, decreased serum leptin and insulin, and regulated plasma glucose. These data clearly demonstrate that the isolated caudal brainstem is sufficient to mediate many aspects of the energetic response to starvation. In intact animals, these responses may be refined by a contribution by more rostral brain areas or by communication between fore- and hind-brain. In the absence of communication from the forebrain, the caudal brainstem is inadequate for maintenance of testosterone levels or lean tissue in fed or fasted animals.
Customized Products: A Competitive Analysis
Authors: Syam Niladri B. , Ruan Ranran , Hess James D.
Published: December 2005

This paper investigates the competitive market for mass-customized products. Competition leads to surprising conclusions: Manufacturers customize only one of a product's two attributes, and each manufacturer chooses the same attribute. Customization of both attributes cannot persist in an equilibrium where firms first choose customization and then choose price, because effort to capture market with customization makes a rival desperate, putting downward pressure on prices.

Equilibrium involves partial or no customization. In partial customization, rival firms do not differentiate their mass-customization programs: If firms customize different attributes, many more consumers are indifferent between the two firms. The elasticity of demand is increased and the resulting price war makes differentiated customization unprofitable. If firms customize the same attribute of a two-attribute product, they should concentrate on the attribute with the smaller heterogeneity in consumers' preferences.

We incorporate consumers’ effort in portraying their preferences as a cost of interaction and provide public policy findings on the well-being of these consumers: When this cost is low, consumers are better off with customization than with standard goods, but firms choose too little customization. The loss in consumer surplus is sometimes captured by the firms, but for low interaction costs, firms' profit-driven behavior is economically inefficient.
Dual Emphasis and the Long-Term Financial Impact of Customer Satisfaction
Authors: Mittal Vikas , Anderson Eugene W. , Sayrak Akin , Tadikamalla Pandu
Published: December 2005

This paper draws on the quality profitability emphasis framework of Rust, Moorman, and Dickson (2002) (Rust, Roland T., Christine Moorman, Peter R. Dickson. 2002. Getting returns from service quality: Revenue expansion, cost reduction, or both. J. Marketing 66(October) 7–24.) to examine the association between customer satisfaction and long-term financial performance among firms that achieve a dual emphasis (focusing on both revenue-expansion and cost-reduction simultaneously, rather than solely emphasizing one over the other). Using a longitudinal data set of 77 firms from the United States, we test this hypothesis and find that the association between customer satisfaction and long-term financial performance is positive and relatively stronger for firms that successfully achieve a dual emphasis. We build on the work of Rust, Moorman, and Dickson (2002), who investigated the financial impact of engaging in the process of achieving a dual emphasis. Collectively, these studies show that while achieving a dual emphasis is desirable for long-run financial success, the process of achieving a dual emphasis may not be as financially rewarding in the short run. Firms pursuing a dual emphasis need to consider both short- and long-term consequences of their strategy.
The Lead-Lag Puzzle of Demand and Distribution: A Graphical Method Applied to Movies
Authors: Krider Robert E. , Li Tieshan , Liu Yong , Weinberg Charles B.
Published: December 2005

Understanding the lead-lag relationship between distribution and demand is an important and challenging issue for all marketers. It is particularly challenging in the movie industry, where the very short lifespan and decaying revenue and exhibition patterns of motion pictures means that the associated time series are short and nonstationary, rendering existing econometric methods unreliable. We propose an alternate method that uses state-space diagrams to determine lead-lag relationships. Straightforward to apply and interpret, it takes advantage of the eye’s ability to see patterns that algebra-based formulations cannot easily recognize. A number of validation tests are provided to illustrate the usefulness and limitations of the method. We study the weekly data for 231 major movies released in 2000–2001. While econometric methods do not provide consistent results, the graphical method of visually inferred causality clearly shows a pattern that demand leads distribution for most movies. In other words, the dominant industry pattern is one of movie exhibitors monitoring box office sales and then responding with screen allocation decisions. The managerial implications of these findings are discussed.
Plasminogen activator inhibitor-1: a review Plasminogen-Aktivator-Inhibitor-1: eine Übersicht
Authors: Pihusch Markus , Pihusch Verena , Holler Ernst
Published: December 2005

Plasminogen activator inhibitor-1 (PAI-1) is the most potent inhibitor of both tissue type (t-PA) and urokinase type plasminogen activator (u-PA) and thus regulates fibrinolysis as well as proteolysis, cell migration, and tumor cell invasiveness. Stimulated by cytokines, lipopolysaccharide, very low density lipoproteins, and transforming growth factor β-1 (TGF β-1), PAI-1 also influences inflammation, metabolic disorders, and fibrotic diseases. PAI-1 is produced in liver cells, adipocytes, smooth muscle cells, and platelets. In pathological conditions, increased PAI-1 levels mainly result from release by endothelial cells or tumor cells. Elevation of PAI-1 activity is described to be associated with pregnancy complications like recurrent miscarriage, pregnancy-induced hypertension, and preeclampsia. Spontaneous abortion seems to be related to the 4G/4G genotype of the polymorphism in the PAI-1 promoter. Women with polycystic ovarian syndrome, which is associated with anovulatory infertility, also show significantly higher PAI-1 levels than healthy controls. Increased PAI-1 levels are found in a number of malignancies and might give information about prognosis and preferential response to certain therapies especially in patients with primary breast cancer. By influencing extracellular matrix turnover, PAI-1 seems to play a role in fibrotic disorders including nephropathy, chronic lung diseases, cardiac fibrosis, and liver fibrosis. Upregulated by inflammatory mediators, PAI-1 levels are increased in sepsis, trauma, surgery, and a variety of diseases associated with inflammatory reactions. PAI-1 is suggested to play a functional role in host response to trauma. Inflammatory states are also found in the pathogenesis of atherosclerosis and the metabolic syndrome. Vascular diseases as well as insulin resistance leading to metabolic state are associated with both elevated PAI-1 levels and the 4G/5G polymorphism of the PAI-1 promoter. The 4G/4G and 4G/5G genotypes were observed to be more frequent in patients with obesity, myocardial infarction, and venous thromboembolism. PAI-1 thus represents an important non-invasive diagnostic criterion in a number of diseases and might reveal new therapeutic strategies.
TAFI: regulating the cross talk between coagulation and fibrinolysis TAFI: Regulierung der Wechselwirkung zwischen Gerinnung und Fibrinolyse
Authors: Marx Pauline F. , Meijers Joost C.M.
Published: December 2005

Thrombin activates thrombin-activatable fibrinolysis inhibitor (TAFI) that removes C-terminal lysines or arginines. The activity of active TAFI (TAFIa) is lost rapidly. TAFIa is not inactivated by proteolysis but converted to an inactive state by a conformational transition. Numerous polymorphisms were identified in the TAFI gene. The TAFI-325Ile variant seems to influence TAFI levels. TAFIa retards plasmin formation and makes plasmin more susceptible to inhibition by antiplasmin; it prevents the conversion of the fibrin fragment DD(E) to fragment DD that impairs fibrin polymerization. The complement-derived factors C3a and C5a as well as bradykinin are further substrates for TAFIa. Elevated TAFI levels were associated with an increased risk of venous thrombosis. TAFI deficiency has been shown to be associated with an enhanced leucocyte migration. The absence of TAFI results in delayed wound healing with disturbed keratinocyte migration. Pro-inflammatory properties of osteopontin are downregulated by TAFIa. Hence, TAFI plays a role – besides in regulation of fibrinolysis – in wound healing, angiogenesis, and inflammation.
Mikrobiologische Liquor-Diagnostik Microbiological diagnostics in CSF
Authors: Rauer Sebastian , Stich Oliver , Bogdan Christian
Published: December 2005

Die standardisierte Untersuchung des Liquors spielt bei der Differentialdiagnose akuter und chronisch entzündlicher ZNS-Erkrankungen eine entscheidende Rolle. In dieser Empfehlung werden Vorschläge zur mikrobiologischen Liquordiagnostik von der Präanalytik über die Basisdiagnostik bis hin zur differenzierten erregerspezifischen und symptomorientierten mikrobiologischen Diagnostik vorgestellt.
Laboratory diagnosis of toxoplasmosis – possibilities and limitations Die Labordiagnose der Toxoplasmose – Möglichkeiten und Grenzen
Authors: Reiter-Owona Ingrid
Published: December 2005

Toxoplasma gondii is a protozoan parasite that is distributed worldwide. Primary infection in immunocompetent individuals is usually subclinical, only few patients exhibit lymphadenopathy. Primary infection in pregnant women may cause severe damage to the fetus and reactivation of a chronic infection can cause life-threatening disease in immunocompromised patients. Diagnosis of toxoplasmosis can be established by serological methods or by direct detection of the parasite or its DNA. This paper discusses the present possibilities and limitations of laboratory diagnosis and points out that specialized centers are needed for a sucessful handling of difficult cases.
Die Diagnostik von Infektionen mit freilebenden Amöben (FLA) Diagnostics of Infections with free-living amoebae (FLA)
Authors: Walochnik Julia , Aspöck Horst
Published: December 2005

Die Bezeichnung “Freilebende Amöben” (FLA) wurde ursprünglich etabliert, um diese Amöben von den parasitischen Entamöben abzutrennen. Es zeigte sich aber, dass auch einige Vertreter der FLA als Krankheitserreger beim Menschen auftreten können. Amöben der Gattung Acanthamoeba sind die Erreger der Acanthamoeba-Keratitis (AK), einer hauptsächlich bei Kontaktlinsenträgern auftretenden Entzündung der Hornhaut des Auges. Außerdem können sie, ebenso wie Balamuthia mandrillaris, vor allem bei Immunsupprimierten, Hautläsionen, Pneumonie und die Granulomatöse Amöbenenzephalitis (GAE) hervorrufen. Die zur Geißelbildung befähigte Naegleria fowleri schließlich ist der Erreger der Primären Amöbenmeningoenzephalitits (PAME).

Während für die Diagnostik der AK zumeist ein mikroskopischer Nachweis mit anschließender Kultur ausreichend ist, sollte bei Infektionen des ZNS – wie grundsätzlich bei systemischen Infektionen – ein molekularbiologischer Nachweis angestrebt werden; hierzu stehen verschiedene PCR-Protokolle und für Infektionen mit N. fowleri zusätzlich ein kommerziell erhältlicher Antigen-Nachweis zur Verfügung. Serologische Tests sind zum Nachweis einer Acanthamoeba-Infektion nahezu ohne diagnostischen Wert, da aufgrund der Ubiquität der FLA nahezu 100% der Normalbevölkerung Antikörper haben. Bei der foudroyant verlaufenden PAME sind serologische Tests vollkommen unbrauchbar, weil wegen der kurzen Inkubationszeit zum Zeitpunkt der akuten Erkrankung (noch) keine Antikörper nachweisbar sind.
Analyse natürlicher Autoantikörper-Repertoires im Humansystem – Ein systembiologisch orientierter Ansatz zum Verständnis Immunglobulin-vermittelter Immunregulation Analysis of natural autoantibody repertoires in humans – investigation of immunoglobulin-mediated immunoregulation at the level of complex biological systems
Authors: Stahl Dorothea
Published: December 2005

Die Bedeutung einer natürlichen Autoreaktivität für die Ausbildung und Aufrechterhaltung von Immuntoleranz ist in den letzten Jahren zunehmend belegt geworden. Die im Rahmen dieses Review zusammengefassten Arbeiten befassen sich mit den Mechanismen der Grenzziehung zwischen physiologischer Autoreaktivität und pathologischer Autoaggression, ausgehend von der humoralen Seite des Immunsystems, und nutzen die vom konzeptionellen Ansatz her systembiologisch orientierte Analyse natürlicher Autoantikörper-Repertoires im Humansystem unter verschiedenen pathologischen Bedingungen zum Verständnis der durch natürliche Autoantikörper vermittelten Immunregulation. Insbesondere die limitierte Anzahl der vom natürlichen IgM- und IgG-Autoantikörper-Repertoire erkannten Antigene und die nur geringe interindividuelle und altersabhängige Varianz der Erkennung dieser Antigene unter physiologischen Bedingungen sind Grundlage für die vergleichende Charakterisierung des Repertoires natürlicher Autoantikörper unter pathologischen Bedingungen. Die zentralen Ergebnisse dieser Arbeiten lassen sich wie folgt darstellen:

Organspezifische Autoimmunerkrankungen sind in der Regel durch organübergreifende Änderungen des natürlichen Autoantikörper-Repertoires charakterisiert.

Organübergreifende Änderungen des natürlichen Autoantikörper-Repertoires können der Manifestation organspezifischer klinisch relevanter Autoaggression vorausgehen.

Die Selektion des natürlichen IgG-Autoantikörper-Repertoires ist T-Zell-abhängig.

Funktionsmechanismen des natürlichen Autoantikörper-Repertoires sind Isotyp-abhängig.

Die Kontrolle IgG-vermittelter Autoreaktivität durch autologes IgM ist ein im Humansystem relevantes pathogenetisches Prinzip.

Aus hämo- und zelltherapeutischer Sicht ist die strukturelle und funktionelle Charakterisierung der das natürliche Autoantikörper-Repertoire determinierenden natürlichen Autoantigene im hämatopoietischen System ein besonders interessantes zukünftiges Forschungsgebiet, insbesondere auch in Anbetracht der zunehmend evident werdenden Plastizität humaner hämatopoietischer Stammzellen. Die in dieser Übersichtsarbeit zusammengefassten Daten zeigen darüber hinaus prinzipiell die Bedeutung des Monitorings des natürlichen Autoantikörper-Repertoires als diagnostischen Ansatz zur Früherkennung und gezielten Prävention pathologischer Autoaggression.
European Code of Practice for Creep Crack Initiation and Growth Testing of Industrially Relevant Specimens
Authors: Dogan B , Ceyhan U , Nikbin KM , Petrovski B , Dean DW
Published: December 2005

The integrity and residual life assessment of high temperature components require information obtained from the material's mechanical, uniaxial creep, creep crack initiation (CCI), and growth (CCG) properties. The information derived from these material tests needs to be validated and harmonized following a Code of Practice (CoP) so that variability in data as well as in the analysis can be optimized between different institutions. The paper describes a CoP for creep crack growth testing of industrially relevant specimens, which was developed within the framework of the partially European Commission (EC) funded project called “CRETE.” Novel aspects of the CoP include advice for testing different specimen geometries, which differ from the standard Compact Tension (C(T)) specimen proposed in the only available CCG testing standard ASTM E 1457. Recommendations for required number of tests, techniques for testing, treatment of test records, reduction of test data, and data analysis are presented. Associated specimen selection guidelines for industrial creep crack initiation and growth testing are also described. Validation tests carried out within the project on Type 316H steel at 550°C and a C-Mn steel at 400°C using relevant specimen geometries are also briefly described. The CoP contains recommended K and C* solutions, Y functions, and η factors, which are used to determine values of the fracture parameters K and C* for the specimen geometries considered, and these are summarized in this paper. Information from these new tests, together with a review of previous creep crack growth tests on nonstandard geometries, have been used in recommending the best method of analysis for the creep crack initiation (CCI) and creep crack growth (CCG) data for a range of creep brittle to creep ductile materials.
Prediction of Scatter in Creep Crack Growth Data from Creep Failure Strain Properties
Authors: Wasmer K , Nikbin KM , Webster GA
Published: December 2005

Procedures are available for determining the creep crack growth (CCG) properties of materials experimentally in terms of the creep fracture mechanics parameter C*. When these properties have not been measured, predictions can be made from models of the cracking process. These models show that creep crack growth rate at a given value of C* is most sensitive to the creep ductility ɛ*f appropriate to the state of stress at a crack tip. For plane stress conditions, it is found that ɛ*f can be taken to be equal to the uniaxial creep ductility ɛf of a material and for plane strain to be given by ɛf/30. Hence, in this paper, uniaxial creep properties on type 316 L(N) austenitic stainless steel and two 9 %Cr steels, designated P91 and P92, in the temperature range 500–750°C are reported and scatter in the data identified from statistical analysis. For each steel, the dependence of creep ductility on stress and temperature is determined. It has been found that none of the rupture time (tR), creep strain rate (˙ε), and net section stress (σnet), parameters has a better relationship with the creep failure strain. Hence, none of these parameters characterizes better than the other the creep ductility's behavior. Additionally, it has been observed that although the creep failure strain of 316 L(N) is independent of these parameters, it increases with temperature. In contrast, the creep failure strain of P91 is slightly sensitive to σnet but is overcompensated by the scatter and so can be assumed stress independent. The creep failure strain of P91 is seen to be also insensitive to temperature. For P92, ɛf goes from a lower to an upper shelf through a transition region. Thus the best solution to characterize the failure strain behavior is to use a polynomial solution. Creep crack growth properties obtained on cracked compact tension and C-shaped specimens are also presented. Probabilistic analysis, based on Monte Carlo simulation methods, is employed to predict scatter in the creep crack growth data from scatter in the uniaxial creep properties. In most instances, close agreement is found between the experimentally measured scatter in the cracking results and that predicted from the scatter obtained from creep ductility data.
Reactor Dosimetry with Niobium
Authors: Wagemans J , Borms L , Willekens M , Oeyen J , Moens A , Kochkin V
Published: December 2005

The main advantages of using niobium in reactor dosimetry are briefly summarized. Some experimental aspects and complications of niobium dosimetry are discussed. Special techniques can be applied to overcome most of these problems. Particular concern has to be given to the detector calibration for the X-ray measurements. The main problem however, embrittlement of pure niobium under intense neutron irradiation, is still not solved. For this purpose a new type of material (Al-10%Nb alloy) was prepared. Although testing of this material is still ongoing, preliminary results are promising. This material moreover does not necessarily require applying special techniques for the X-ray measurements. Finally it is explained that niobium is a suitable material for the determination of thermal and epithermal fluences in high flux environments.
Arthroscopic Treatment of the First Anterior Shoulder Dislocation in Young Skiers
Authors: Yiannakopoulos CK , Zacharopoulos AN , Antonogiannakis E
Published: December 2005

The purpose of this paper was to describe the results of arthroscopic shoulder stabilization in skiers following the first episode of anterior dislocation. Between 1999 and 2001, 18 patients aged 19–27 years were treated arthroscopically following an acute, primary anterior shoulder dislocation. All patients were active skiers and were injured during skiing. The detached anterior labrum was reattached on the glenoid articular surface using 2–5 bone anchors, mainly metallic. Postoperative evaluation was performed with the Rowe-Zarins scale with a mean follow up of 31 months. There have been no recurrences and all patients returned to their preinjury level. According to the Rowe-Zarins scale the outcome was excellent in 15/17 cases. Arthroscopic shoulder stabilization in selected, active patients provides good mid-term functional results. The quality of glenohumeral ligaments was better compared to patients with chronic instability and the secondary injuries were less common.
Instrumentation for Determining the Local Damping Capacity in Honeycomb Sandwich Composites
Authors: Lincoln JD , Rieger LE , Earthman JC
Published: December 2005

A mechanical percussion probe originally designed for determining the damping capacity of dental implants has been adapted to assess the damping capacity in a localized area of honeycomb sandwich composites without inflicting damage on the structure. The new instrumentation is light, portable, and inexpensive compared with other testing techniques. Furthermore, it allows quick access to areas not easily accessible by ultrasonic methods. The damping capacity of honeycomb sandwich composite structures is of interest to engineers as it reflects the ability of a material to absorb and isolate vibration. Honeycomb sandwich structures with various damping treatments were constructed and accurately evaluated with the instrumentation. Detection capabilities and limitations were also evaluated.
Vapor Permeances, Air Permeances, and Water absorption Coefficients of Building Membranes
Authors: Kumaran MK , Lackey JC , Normandin N , van Reenen D
Published: December 2005

Building membranes are integral parts of North American buildings. Some are installed beneath commonly used exterior claddings, brick, and stucco to reduce the risk of water infiltration into the wall systems. Others are used for controlling vapor diffusion though the envelope or as the airtight element of the air barrier system of the envelope. To determine the suitability of a membrane for its intended application, it is necessary to have reliable information on its inherent physical properties. This paper reports the water vapor permeance, the air permeance, and the water absorption coefficient for 18 building membranes that are found in North American markets today. These membranes include paper-based as well as polymer-based materials. The properties reported here show that at the design stage most of the membranes can be considered as the airtight element of air barrier systems and as part of the second line of defense against rainwater penetration. The membranes provide a range of values for water vapor permeance and therefore open up opportunities for a designer to integrate innovative vapor diffusion control strategies for exterior walls and to prolong their service lives.
Direct Shear Behavior of Carbon Fiber-Reinforced Polymer Laminates and Concrete
Authors: Hsu CTT , Punurai W , Jia Y , Bian H
Published: December 2005

This paper explores the direct shear behavior between carbon fiber-reinforced polymer (CFRP) laminates and concrete. To study the push-off strength and slip relationship of externally bonded strengthening system, a new test setup is proposed herein. In this research, a total of 27 specimens are tested. The test variables include the maximum compressive strength of concrete, from 4000 to 12000 psi. With this test setup, it has been found to be able to investigate the direct shear condition between the CFRP laminates and concrete. Based on the present test results, empirical formulas to account for the push-off strength and slip relationship of various concrete compressive strengths are developed. This relationship enables further understanding of the transfer mechanism between the CFRP laminates and concrete. Also, the effect of salt water on the ultimate direct shear strength of the CFRP strengthening system is discussed.
Developing a Geographical Information System Database and Spatial Analysis for a Forest Biomass Resource Assessment
Authors: Hughes EM , Mackes KH
Published: December 2005

This study was done to determine the volume, type, and distribution of forest biomass generated in Larimer County, Colorado. The data were compiled within ArcGISTm, a Geographical Information System (GIS) program to graphically display where they exist. Presenting the data using a GIS format created a clear visual representation of wood supply distribution for Larimer County. The GIS database was developed from many sources, including data provided by the U.S. Forest Service and Colorado State Forest Service, and data from IRS tax records (Agricultural tax credit records). The database summarizes forest biomass generation in terms of harvested acres, volumes, and product type removed. Products were typically in the form of fuelwood, chips, posts, and small saw logs. Data were converted into a format compatible with ArcGISTM, thus contained in one easily understood database.
Durability Effects on Flexural Behavior of Fly Ash Stabilized Limestone Aggregate
Authors: Khoury N , Zaman M
Published: December 2005

This paper examines the flexural behavior of beams, representing a cementitiously stabilized aggregate base, under cyclic loading. Specifically, the effects of different freeze-thaw (F-T) procedures and number of F-T cycles on flexural response are studied. Aggregate beams stabilized with 10 % class C fly ash, cured for different periods (1 h, 3 days, and 28 days) and subjected to F-T cycles are tested for resilient modulus in flexure (Mrf) and modulus of rupture (MOR). The Mrf values decreased with increasing F-T cycles. Changes in Mrf are sensitive to curing periods. Reduction in Mrf and MOR and degradation in specimens are attributed to the increase in moisture content during the thawing phase and formation of ice lenses during the freezing phase. Degradation occurs when the expansion of ice lenses exceeds the pore space available. A correlation between Mrf and stress ratio shows that Mrf decreases with increasing stress ratio, in an overall sense. A steep decrease in Mrf is observed for stress ratios in the range of 0.1 to 0.3, beyond which no significant reduction is evident.
Effects of Laundering on Environmentally-Improved and Classic Denim Fabrics
Authors: Fox A , Moore MA
Published: December 2005

Denim manufactures are capitalizing on consumers' environmental awareness and are producing fabrics constructed from environmentally-improved fibers. This experimental study examined the effects of launderings on the breaking strength, and breaking elongation of environmentally improved and classic denim fabrics. There were significant differences in the percent changes in breaking strength and elongation of the environmentally-improved and classic denim fabrics as a result of repeated launderings. The 80 % cotton/20 % PET (poly (ethylene teraphthalate)) maintained its strength during laundering. The organic cotton performed similarly to the two classic fabrics; it proved robust to laundering with respect to breaking strength and breaking elongation. Overall, the environmentally-improved denim fabrics performed similarly to the classic denim fabrics with respect to breaking strength and breaking elongation.
Increased Prevalence of Fetal Thrombi in Monochorionic-Twin Placentas
Authors: Sato Yuichiro , Benirschke Kurt
Published: December 2005

OBJECTIVE. Fetal vessel thrombosis has been related to pregnancy complications and adverse neonatal outcomes in singleton pregnancies, but the clinical and pathologic characteristics of fetal thrombosis in twin pregnancy are still ill defined.

METHODS. To clarify the characteristics of fetal thrombosis in twins, we reviewed the histology slides and medical records of live-born infants of twin pregnancies involving the live birth of at least 1 fetus (monochorionic: 389 cases; dichorionic: 780 cases) and singleton pregnancies (1162 cases).

RESULTS. The incidence of fetal thrombosis in monochorionic-twin pregnancies was significantly higher than that of dichorionic-twin and singleton pregnancies (5.1% vs 3.0% and 2.8%, respectively). The incidence of velamentous umbilical cord insertion in monochorionic- and dichorionic-twin placentas was also higher than in singleton placentas (12% and 7% vs 2%, respectively). Fetal thrombosis in twin placentas was associated with intrauterine growth restriction. In monochorionic twins, fetal thrombosis was associated with co-twin fetal death, but in dichorionic twins no correlation was identified. Microscopically, fetal vessel thrombosis in twin placentas was associated with vascular cushions (fibrous hyperplasia of fetal vessel), as is the case occasionally in singletons.

CONCLUSIONS. The incidence of fetal vessel thrombosis in monochorionic placentas was higher than that seen in dichorionic-twin placentas and singleton gestations. Fetal vessel thrombosis in twin pregnancies showed a correlation with intrauterine growth restriction, peripheral cord insertions, and major vascular cushions.
A Road Map Toward Defining the Role of Smad Signaling in Hematopoietic Stem Cells
Authors: Utsugisawa Taiju , Moody Jennifer L. , Aspling Marie , Nilsson Eva , Carlsson Leif , Karlsson Stefan
Published: December 2005

The transforming growth factor-β (TGF-β) superfamily encompasses the ligands and receptors for TGF-β, bone morphogenic proteins (BMPs), and Activins. Cellular response to ligand is context-dependent and may be controlled by specificity and/or redundancy of expression of these superfamily members. Several pathways within this family have been implicated in the proliferation, differentiation, and renewal of hematopoietic stem cells (HSCs); however, their roles and redundancies at the molecular level are poorly understood in the rare HSC. Here we have characterized the expression of TGF-β superfamily ligands, receptors, and Smads in murine HSCs and in the Lhx2-hematopoietic progenitor cell (Lhx2-HPC) line. We demonstrate a remarkable likeness between these two cell types with regard to expression of the majority of receptors and Smads necessary for the transduction of signals from TGF-β, BMP, and Activin. We have also evaluated the response of these two cell types to various ligands in proliferation assays. In this regard, primary cells and the Lhx2-HPC line behave similarly, revealing a suppressive effect of Activin-A that is similar to that of TGF-β in bulk cultures and no effect of BMP-4 on proliferation. Signaling studies that verify the phosphorylation of Smad2 (Activin and TGF-β) and Smad1/5 (BMP) confirm cytosolic responses to these ligands. In addition to providing a thorough characterization of TGF-β superfamily expression in HSCs, our results define the Lhx2-HPC line as an appropriate model for molecular characterization of Smad signaling.
A Focused Microarray to Assess Dopaminergic and Glial Cell Differentiation from Fetal Tissue or Embryonic Stem Cells
Authors: Luo Yongquan , Schwartz Catherine , Shin Soojung , Zeng Xianmin , Chen Nong , Wang Yue , Yu Xiang , Rao Mahendra S.
Published: December 2005

We designed oligonucleotide gene-specific probes to develop a focused array that can be used to discriminate between neural phenotypes, identify biomarkers, and provide an overview of the process of dopaminergic neuron and glial differentiation. We have arrayed approximately 100 genes expressed in dopaminergic neurons, oligodendrocytes, and astrocytes, an additional 200 known cytokines, chemokines, and their respective receptors, as well as markers for pluripotent and progenitor cells. The gene-specific 60-mer 3′ biased oligonucleotides for these 281 genes were arrayed in a 25 × 12 format based on function. Using human adult brain substantia nigra, human embryonic stem cells (ESCs), and the differentiated progeny of pluripotent cells, we showed that this array was capable of distinguishing dopaminergic neurons, glial cells, and pluripotent cells by their gene expression profiles in a concentration-dependent manner. Using linear correlation coefficients of input RNA with output intensity, we identified a list of genes that can serve as reporting genes for detecting dopaminergic neurons, glial cells, and contaminating ESCs and progenitors. Finally, we monitored NTera2 differentiation toward dopaminergic neurons and have shown the ability of this array to distinguish stages of differentiation and provide important clues to factors regulating differentiation, the degree of contaminating populations, and stage of cell maturity. We suggest that this focused array will serve as a useful complement to other large-scale arrays in routine assessment of cell properties prior to their therapeutic use.
Specific MicroRNAs Modulate Embryonic Stem Cell–Derived Neurogenesis
Authors: Krichevsky Anna M. , Sonntag Kai-C. , Isacson Ole , Kosik Kenneth S.
Published: December 2005

MicroRNAs (miRNAs) are recently discovered small non-coding transcripts with a broad spectrum of functions described mostly in invertebrates. As post-transcriptional regulators of gene expression, miRNAs trigger target mRNA degradation or translational repression. Although hundreds of miRNAs have been cloned from a variety of mammalian tissues and cells and multiple mRNA targets have been predicted, little is known about their functions. So far, a role of miRNA has only been described in hematopoietic, adipocytic, and muscle differentiation; regulation of insulin secretion; and potentially regulation of cancer growth. Here, we describe miRNA expression profiling in mouse embryonic stem (ES) cell– derived neurogenesis in vitro and show that a number of miRNAs are simultaneously co-induced during differentiation of neural progenitor cells to neurons and astrocytes. There was a clear correlation between miRNA expression profiles in ES cell– derived neurogenesis in vitro and in embryonal neurogenesis in vivo. Using both gain-of-function and loss-of-function approaches, we demonstrate that brain-specific miR-124a and miR-9 molecules affect neural lineage differentiation in the ES cell– derived cultures. In addition, we provide evidence that signal transducer and activator of transcription (STAT) 3, a member of the STAT family pathway, is involved in the function of these miRNAs. We conclude that distinct miRNAs play a functional role in the determination of neural fates in ES cell differentiation.
A key means to signaling the evaluative component in storytelling
Authors: Tickoo Asha
Published: December 2005

Though scholars interested in ESL writing pedagogy would like to believe otherwise, most students in high school and college English language courses are not, in fact, required to write academic prose. Rather they are, by and large, asked to write the personal narrative, a genre of prose similar in very fundamental ways to the prototype story. The personal narrative is a challenge because, like the prototype story, it is more than a mere report of events in past time. It is a report of events in past time infused with, what has been identified as the defining component of the story, the evaluative component. The evaluative component enables the writer to represent the dissimilar impact of successive narrative events to the developing theme. In this paper, I will address one significant means of signaling the dissimilar impact of successive narrative events, and the problems learners have with its proper use. In the prototype personal narrative/ story, the temporal movement effected by successive narrative events is not the same. There is non-uniformity in the pace and quality, of the temporal movement, from one narrative event to the next. I will provide a description of the sentence-level mode of implementing this particular means of evaluation in the prose of skilled writers, and examine a representative sample of ESL data to show the difficulty learners face with its implementation. This understanding will be used to generate suggestions for pedagogy which specifically address this area of difficulty.