bluuebunny/crossref_metadata_2025 huggingface dataset:
Predicting Transition in Turbomachinery—Part II: Model Validation and Benchmarking
Authors: Praisner T. J. , Grover E. A. , Rice M. J. , Clark J. P.
Published: January 2007

The ability to predict boundary layer transition locations accurately on turbomachinery airfoils is critical both to evaluate aerodynamic performance and to predict local heat-transfer coefficients with accuracy. Here we report on an effort to include empirical transition models developed in Part I of this report in a Reynolds averaged Navier-Stokes (RANS) solver. To validate the new models, two-dimensional design optimizations utilizing transitional RANS simulations were performed to obtain a pair of low-pressure turbine airfoils with the objective of increasing airfoil loading by 25%. Subsequent experimental testing of the two new airfoils confirmed pre-test predictions of both high and low Reynolds number loss levels. In addition, the accuracy of the new transition modeling capability was benchmarked with a number of legacy cascade and low-pressure turbine (LPT) rig data sets. Good agreement between measured and predicted profile losses was found in both cascade and rig environments. However, use of the transition modeling capability has elucidated deficiencies in typical RANS simulations that are conducted to predict component performance. Efficiency-versus-span comparisons between rig data and multi-stage steady and time-accurate LPT simulations indicate that loss levels in the end wall regions are significantly under predicted. Possible causes for the under-predicted end wall losses are discussed as well as suggestions for future improvements that would make RANS-based transitional simulations more accurate.
Effect of Tip and Pressure Side Coolant Injection on Heat Transfer Distributions for a Plane and Recessed Tip
Authors: Nasir Hasan , Ekkad Srinath V. , Bunker Ronald S.
Published: January 2007

The present study investigates the effects of coolant injection on adiabatic film effectiveness and heat transfer coefficients from a plane and recessed tip of a high pressure turbine first stage rotor blade. Three cases where coolant is injected from (a) five orthogonal holes located along the camber line, (b) seven angled holes located near the blade tip along the pressure side, and (c) combination cases when coolant is injected from both tip and pressure side holes were studied. The pressure ratio (inlet total pressure to exit static pressure for the cascade) across the blade row was 1.2, and the experiments were run in a blow-down test rig with a four-blade linear cascade. The Reynolds number based on cascade exit velocity and axial chord length was 8.61×105 and the inlet and exit Mach numbers were 0.16 and 0.55, respectively. A transient infrared technique was used to measure adiabatic film effectiveness and heat transfer coefficient simultaneously for three blowing ratios of 1.0, 2.0, and 3.0. For all the cases, gap-to-blade span ratio of 1% was used. The depth-to-blade span ratio of 0.0416 was used for the recessed tip. Pressure measurements on the shroud were also taken to characterize the leakage flow and understand the heat transfer distributions. For tip injection, when blowing ratio increases from 1.0 to 2.0, film effectiveness increases for both plane and recessed tip and heat transfer coefficient decreases for both plane and recessed tip. At blowing ratio 3.0, lift-off is observed for both cases. In case of pressure side coolant injection and for plane tip, lift-off is observed at blowing ratio 2.0 and reattachments of jets are observed at blowing ratio 3.0. But, almost no effectiveness is observed for squealer tip at all blowing ratios with pressure side injection with reduced heat transfer coefficient along the pressure side. For combination case, very high effectiveness is observed at blowing ratio 3.0 for both plane and recessed blade tip. It appears that for this high blowing ratio, coolant jets from the tip hit the shroud first and then reattach back onto the blade tip with very high heat transfer coefficients for both plane and recessed blade tip.
Advanced Modeling of Underplatform Friction Dampers for Analysis of Bladed Disk Vibration
Authors: Petrov E. P. , Ewins D. J.
Published: January 2007

Advanced structural dynamic models for both wedge and split underplatform dampers have been developed. The new damper models take into account inertia forces and the effects of normal load variation on stick-slip transitions at the contact interfaces. The damper models are formulated for the general case of multiharmonic forced response analysis. An approach for using the new damper models in the dynamic analysis of large-scale finite element models of bladed disks is proposed and realized. Numerical investigations of bladed disks are performed to demonstrate the capabilities of the new models and an analysis of the influence of the damper parameters on the forced response of bladed disks is made.
Industrial Wastewater Treatment by Photochemical Processes Based on Solar Energy
Authors: Nascimento Claudio A. O. , Teixeira Antonio Carlos S. C. , Guardani Roberto , Quina Frank H. , Chiavone-Filho Osvaldo , Braun André M.
Published: January 2007

Background: The solar photo-Fenton process has enormous potential for becoming a viable alternative to conventional processes for the treatment of industrial wastewater. However, the costs associated with the use of artificial irradiation have hindered many times industrial application of these processes. Method of Approach: In this work, the photo-Fenton remediation of various industrial wastewaters (containing silicones, pesticides, phenol and hydrocarbons, model, and real) in aqueous systems has been studied using Fe(II), H2O2, and UV-visible sunlight. Experiments were carried out using a concentrating parabolic trough reactor (PTR) and a nonconcentrating falling-film reactor. Results: In general, at low contaminant concentration, more than 90% of the total organic carbon content could be converted to inorganic carbon within about 2-3h, using sunlight, in reactors of different geometry. Conclusions: Solar light can be used either as an effective complementary or alternative source of photons to the photo-Fenton degradation process of a diversity of chemical pollutants.
Solar Disinfection Kinetic Design Parameters for Continuous Flow Reactors
Authors: Gill Laurence W. , McLoughlin Orlaith A.
Published: January 2007

The main UV dose-related kinetic parameters influencing solar disinfection have been investigated for the design of a continuous flow reactor suitable for a village-scale water treatment system. The sensitivities of different pathogenic microorganisms under solar light in batch processes have been compared in order to define their relative disinfection kinetics with E. coli used as a baseline organism. Dose inactivation kinetics have been calculated for small scale disinfection systems operating under different conditions such as reflector type, flow rate, process type, photocatalytic enhancement, and temperature enhancement using E. coli K-12 as a model bacterium. Solar disinfection was shown to be successful in all experiments with a slight improvement in the disinfection kinetic found when a fixed TiO2 photocatalyst was placed in the reactor. There was also evidence that the photocatalytic mechanism prevented regrowth in the post-irradiation environment. A definite synergistic solar UV∕temperature effect was noticed at a temperature of 45°C. The disinfection kinetics for E. coli in continuous flow reactors have been investigated with respect to various reflector shapes and flow regimes by carrying out a series of experiments under natural sunlight. Finally, photocatalytic and temperature enhancements to the continuous flow process have been evaluated.
Appropriateness of Antimicrobial Therapy Measured by Repeated Prevalence Surveys
Authors: Willemsen Ina , Groenhuijzen Anneke , Bogaers Diana , Stuurman Arie , van Keulen Peter , Kluytmans Jan
Published: January 2007

Prudent use of antibiotics is mandatory to control antibiotic resistance. The objective of this study was to determine if prevalence surveys are useful tools to determine the appropriateness of antimicrobial therapy (AMT) and determinants of inappropriate AMT. The study was performed in a 1,350-bed teaching hospital including all medical specialities. Six consecutive 1-day prevalence surveys of in-patients were performed twice yearly from 2001 to 2004. Data on the demographics, infections, and AMT were gathered. The appropriateness of AMT was assessed according to a standardized algorithm based on the local AMT prescription guidelines. On average, 684 patients were included in each survey (total, 4,105). The use of AMT as determined in the prevalence survey corresponded to the annual data from the pharmacy department. Nine hundred thirty-eight (22.9%) of the patients received AMT, and in 351 (37.4%) of these patients AMT was inappropriate. Only 25 (0.6%) patients did not receive AMT, although it was indicated. After multivariate analysis, the use of quinolones was the only statistically significant variable associated with inappropriate use. Prevalence surveys proved to be useful tools to judge the appropriateness of AMT and to identify determinants of inappropriate use. This study shows that in a setting with a low use of AMT, there are few patients who inadvertently do not receive AMT. On the other hand, a substantial number of the patients are treated inappropriate.
Antibiotic Resistance of
Campylobacter jejuni
and
Campylobacter coli
Clinical Isolates from Poland
Authors: Wardak Sebastian , Szych Jolanta , Zasada Aleksandra Anna , Gierczyński Rafał
Published: January 2007

We tested 102
Campylobacter jejuni
and 6
Campylobacter coli
clinical isolates from Poland. All were susceptible to erythromycin. Among the tested
C. jejuni
isolates 55.9% and 13.7% were resistant to ciprofloxacin and tetracycline, respectively. Replacement of Thr86 with Ile in GyrA and a plasmid-borne
tet
(O) gene were the main resistance mechanisms for fluoroquinolones and tetracycline, respectively.
Clonal Diversity and Resistance Mechanisms in Tetracycline-Nonsusceptible
Streptococcus pneumoniae
Isolates in Poland
Authors: Izdebski Radosław , Sadowy Ewa , Fiett Janusz , Grzesiowski Paweł , Gniadkowski Marek , Hryniewicz Waleria
Published: January 2007

The frequency of tetracycline resistance in
Streptococcus pneumoniae
isolates in Poland is one of the highest in Europe. The aim of this study was to analyze the clonal diversity and resistance determinants of tetracycline-nonsusceptible
S. pneumoniae
isolates identified in Poland and to investigate the effect of tetracycline resistance on their susceptibilities to tigecycline, doxycycline, and minocycline. We have analyzed 866 pneumococcal isolates collected from 1998 to 2003 from patients with respiratory tract diseases, and 242 of these (27.9%) were found to be resistant to tetracycline. All of the resistant isolates were characterized by testing of their susceptibilities to other antimicrobials, serotyping, pulsed-field gel electrophoresis (PFGE), and identification of tetracycline resistance genes and transposons. Selected isolates representing the main PFGE types were analyzed by multilocus sequence typing. Among the isolates investigated, 27 serotypes and 146 various PFGE patterns, grouped into 90 types, were discerned. The most common PFGE type, corresponding to serotype 19F and sequence type 423, was represented by 22.3% of all of the tetracycline-resistant isolates. The
tet
(M) gene was the sole resistance gene in the group of isolates studied, and in over 96% of the isolates, the Tn
916
family of
tet
(M)-containing conjugative transposons was detected. Several isolates contained specific variants of the transposons, the Tn
1545
-like, Tn
3872
-like, or Tn
2009
-like element. The correlation between the MICs of tetracycline, doxycycline, and minocycline was revealed, whereas no cross-resistance to tetracycline and tigecycline was observed.
Deletion of the Glucose-6-Phosphate Dehydrogenase Gene Kl
ZWF1
Affects both Fermentative and Respiratory Metabolism in
Kluyveromyces lactis
Authors: Saliola Michele , Scappucci Gina , De Maria Ilaria , Lodi Tiziana , Mancini Patrizia , Falcone Claudio
Published: January 2007

In
Kluyveromyces lactis
, the pentose phosphate pathway is an alternative route for the dissimilation of glucose. The first enzyme of the pathway is the glucose-6-phosphate dehydrogenase (G6PDH), encoded by Kl
ZWF1
. We isolated this gene and examined its role. Like
ZWF1
of
Saccharomyces cerevisiae
, Kl
ZWF1
was constitutively expressed, and its deletion led to increased sensitivity to hydrogen peroxide on glucose, but unlike the case for
S. cerevisiae
, the Kl
zwf1Δ
strain had a reduced biomass yield on fermentative carbon sources as well as on lactate and glycerol. In addition, the reduced yield on glucose was associated with low ethanol production and decreased oxygen consumption, indicating that this gene is required for both fermentation and respiration. On ethanol, however, the mutant showed an increased biomass yield. Moreover, on this substrate, wild-type cells showed an additional band of activity that might correspond to a dimeric form of G6PDH. The partial dimerization of the G6PDH tetramer on ethanol suggested the production of an NADPH excess that was negative for biomass yield.
Toxoplasma gondii
Targets a Protein Phosphatase 2C to the Nuclei of Infected Host Cells
Authors: Gilbert Luke A. , Ravindran Sandeep , Turetzky Jay M. , Boothroyd John C. , Bradley Peter J.
Published: January 2007

Intracellular pathogens have evolved a wide array of mechanisms to invade and co-opt their host cells for intracellular survival. Apicomplexan parasites such as
Toxoplasma gondii
employ the action of unique secretory organelles named rhoptries for internalization of the parasite and formation of a specialized niche within the host cell. We demonstrate that
Toxoplasma gondii
also uses secretion from the rhoptries during invasion to deliver a parasite-derived protein phosphatase 2C (PP2C-hn) into the host cell and direct it to the host nucleus. Delivery to the host nucleus does not require completion of invasion, as evidenced by the fact that parasites blocked in the initial stages of invasion with cytochalasin D are able to target PP2C-hn to the host nucleus. We have disrupted the gene encoding PP2C-hn and shown that PP2C-hn-knockout parasites exhibit a mild growth defect that can be rescued by complementation with the wild-type gene. The delivery of parasite effector proteins via the rhoptries provides a novel mechanism for
Toxoplasma
to directly access the command center of its host cell during infection by the parasite.
Echinococcus granulosus
Antigen B Impairs Human Dendritic Cell Differentiation and Polarizes Immature Dendritic Cell Maturation towards a Th2 Cell Response
Authors: Riganò Rachele , Buttari Brigitta , Profumo Elisabetta , Ortona Elena , Delunardo Federica , Margutti Paola , Mattei Vincenzo , Teggi Antonella , Sorice Maurizio , Siracusano Alessandra
Published: January 2007

Despite inducing a strong host cellular and humoral immune response, the helminth
Echinococcus granulosus
is a highly successful parasite that develops, progresses, and ultimately causes chronic disease. Although surgery remains the preferred therapeutic option, pharmacological research now envisages antihelminthic strategies. To understand the mechanisms that
E. granulosus
uses to escape host immunosurveillance and promote chronic infection, we investigated how two hydatid cyst components, purified antigen B (AgB) and sheep hydatid fluid (SHF), act on host dendritic cell (DC) differentiation from monocyte precursors and how they influence maturation of DC that have already differentiated. We evaluated the immunomodulatory potential of these antigens by performing immunochemical and cytofluorimetric analyses of monocyte-derived DCs from healthy human donors. During monocyte differentiation, AgB and SHF downmodulated CD1a expression and upregulated CD86 expression. Compared with immature DCs differentiated in medium alone (iDCs), AgB- and SHF-differentiated cells stimulated with lipopolysaccharide included a significantly lower percentage of CD83
+
cells (
P
< 10
−4
) and had weaker costimulatory molecule expression. When stimulated with AgB and SHF, iDCs matured and primed lymphocytes towards the Th2 response typical of
E. granulosus
infection. SHF and particularly AgB reduced the production of interleukin-12p70 (IL-12p70) and tumor necrosis factor alpha in lipopolysaccharide-stimulated iDCs. Anti-IL-10 antibodies increased the levels of IL-12p70 secretion in AgB- and SHF-matured DCs. AgB and SHF induced interleukin-1 receptor-associated kinase phosphorylation and activated nuclear factor-κB, suggesting that Toll-like receptors could participate in
E. granulosus
-stimulated DC maturation. These results suggest that
E. granulosus
escapes host immunosurveillance in two ways: by interfering with monocyte differentiation and by modulating DC maturation.
Both Epsilon-Toxin and Beta-Toxin Are Important for the Lethal Properties of
Clostridium perfringens
Type B Isolates in the Mouse Intravenous Injection Model
Authors: Fernandez-Miyakawa Mariano E. , Fisher Derek J. , Poon Rachael , Sayeed Sameera , Adams Vicki , Rood Julian I. , McClane Bruce A. , Uzal Francisco A.
Published: January 2007

Clostridium perfringens
is capable of producing up to 15 toxins, including alpha-toxin (CPA), beta-toxin (CPB), epsilon-toxin (ETX), enterotoxin, beta2-toxin (CPB2), and perfringolysin O. Type B isolates, which must produce CPA, CPB, and ETX, are associated with animal illnesses characterized by sudden death or acute neurological signs, with or without intestinal damage. Type B pathogenesis in ruminants is poorly understood, with some animals showing lesions and clinical signs similar to those caused by either type C or type D infections. It is unknown whether host or environmental conditions are dominant for determining the outcome of type B disease or if disease outcomes are determined by variable characteristics of type B isolates. To help clarify this issue, 19 type B isolates were evaluated for toxin production during late-log-phase growth via quantitative Western blotting and by biological activity assays. Most type B isolates produced CPB levels similar to those produced by type C isolates in vitro and have the potential to produce genotype C-like disease. The lethality of type B isolate supernatants administered intravenously to mice was evaluated with or without prior trypsin treatment, and monoclonal antibody neutralization studies also were performed. Correlation analyses comparing toxin levels in type B supernatants versus lethality and neutralization studies both found that the main contributor to lethality without pretreatment with trypsin was CPB, whereas neutralization studies indicated that CPB and ETX were both important after trypsin pretreatment. At least part of the CPB produced by type B isolates remained active after trypsin treatment. However, the overall lethalities of most supernatants were lower after trypsin pretreatment. Also, there was a significant association between ETX, CPB2, and CPA production in vitro among type B isolates. However, our results suggest that both CPB and ETX are likely the most important contributors to the pathogenesis of
C. perfringens
type B infections in domestic animals.
Biologic therapies: what and when?
Authors: Johnston Sarah L
Published: January 2007

Over the past two decades, major advances have been made in the understanding of the immune system and disease pathogenesis. This has coincided with the development of biologic therapies—monoclonal antibodies and fusion proteins. The decision of when to use such treatment in the clinic is not always straightforward. In addition to immune biology, the focus of this review will be on the application of these treatments to immune-mediated diseases and the molecular targets involved in pathogenesis, specifically those that have US Food and Drug Administration/European Medicines Agency approval. Brief comments will be made on biologics that have approval for non-immune disorders.
Disseminated gonococcal infection presenting as vasculitis: a case report: Figure 1
Authors: Jain Sangita , Win Htet Nwe , Chalam Venkat , Yee Lian
Published: January 2007

A 50-year-old man with alcoholic liver disease presented with fever, tenosynovitis, polyarthritis and a vasculitic rash on the hands and feet for 4 days. He had neutrophilia and raised inflammatory markers. He had no history of sore throat, urethral discharge or travel abroad. His initial blood cultures were negative, and he was treated for vasculitis with steroids. The rash and arthritis seemed to improve initially, but he had another episode of fever. Repeat blood cultures grewNeisseria gonorrhoeae,and he received intravenous ceftriaxone followed by oral ciprofloxacin. He had marked improvement in rash, tenosynovitis and arthritis, and the fever dropped. He also had chlamydial urethritis and received azithromycin. The presentation of disseminated gonococcal infection after a presumptive episode of asymptomatic urethral gonorrhoea is highlighted.
Adenocarcinoma arising in a gastrocystoplasty: Figure 1
Authors: Balachandra B , Swanson P E , Upton M P , Yeh M M
Published: January 2007

Gastrocystoplasty is a form of surgical bladder augmentation or neobladder used to restore bladder capacity and compliance in children and in patients with neurogenic bladder. Other forms of bladder augmentation include ileocystoplasty and colocystoplasty. Reported complications of gastrocystoplasty include post-operative bleeding, haematuria, stricture, metabolic alkalosis and rupture of the gastric segment. There are reports of adenocarcinomas arising in the setting of ileocystoplasty and colocystoplasty. However, the first case of adenocarcinoma arising in the setting of a gastrocystoplasty is reported.
Distinguishing diabetic nephropathy from other causes of glomerulosclerosis: an update
Authors: Alsaad K O , Herzenberg A M
Published: January 2007

Diabetic nephropathy is a common cause of end-stage renal disease worldwide. It is characterised by diffuse or nodular glomerulosclerosis, afferent and efferent hyaline arteriolosclerosis, and tubulointerstitial fibrosis and atrophy. Diffuse and nodular diabetic glomerulosclerosis share similar histological features with other clinical conditions. Immunofluorescence and electron microscopy studies, and clinicopathological correlation are essential to differentiate diabetic nephropathy from other conditions that result in diffuse and nodular glomerulosclerosis.
Plasmablastic lymphoma presenting as a paravertebral mass in a patient with Crohn’s disease after immunosuppressive therapy
Authors: Redmond M , Quinn J , Murphy P , Patchett S , Leader M
Published: January 2007

The case of a 32-year-old man with a paravertebral mass and skin nodules, occurring against a background of immunosuppressive therapy for Crohn’s disease, is presented. The tumours showed morphological and immunophenotypical features of plasmablastic lymphoma. To our knowledge, this is the first reported case of plasmablastic lymphoma presenting in this location, and also after immunosuppression with infliximab treatment for Crohn’s disease.
A summary of the symposium “Current strategies in the prevention and treatment of obesity”
Authors: Katzmarzyk Peter T.
Published: January 2007

This symposium addressed important issues related to the prevention and treatment of obesity and provided practical advice for health professionals. The importance of the maintenance of long-term lifestyle changes were emphasized throughout the symposium as being an integral component to the maintenance of healthy body masses.
Mechanisms of bone remodeling during weight-bearing exercise
Authors: Zernicke Ronald , MacKay Christopher , Lorincz Caeley
Published: January 2007

Exercise-induced mechanical loading can have potent effects on skeletal form and health. Both intrinsic and extrinsic factors contribute to bone structure and function. Mechanical simuli (e.g., strain magnitude, frequency, rate, and gradients, as well as fluid flow and shear stress) have potent influences on bone-cell cytoskeleton and associated signalling pathways. Although the immature skeleton may be more able to benefit from exercise, a skeletally mature population can also benefit from exercise programs aimed at increasing the functional loads to which the skeleton is exposed. The definitive explanation of mechanical-loading and (or) bone-cell mechanotransductive phenomena, however, remains elusive. Here, we briefly review the structural and anatomical foundation for bone adaptation, focusing on mechanical loading effects on bone, linked to the roles of integrins, cytoskeleton, membrane channels, and auto- and paracrine factors in bone modeling and remodeling.
Molecular regulation of myogenic progenitor populations
Authors: Parise Gianni , O’Reilly Ciara E. , Rudnicki Michael A.
Published: January 2007

Skeletal muscle regeneration and adaptation to exercise require the actions of muscle satellite cells. Muscle satellite cells are thought to play an integral role in the process of exercise adaptation, but have also been shown to possess the capacity to fully regenerate muscle tissue following destructive muscle injury. We now know that molecular regulation of satellite cells involves the coordinated actions of a series of transcriptional networks that leads to myogenic commitment, cell-cycle entry, proliferation, and terminal differentiation. Additionally, Pax7 is a paired-box transcription factor that has been identified as playing a critical role in satellite cell regulation. It remains debatable, however, whether Pax7 is required for the specification of satellite cells and (or) whether it is playing a vital role in self-renewal and maintenance of the satellite cell population. In recent years, the emergence of atypical myogenic progenitor populations has added a new dimension to muscle repair, and significant interest has been focused on identifying populations such as bone-marrow-derived stem cells that have the ability to contribute to muscle. Interestingly, elucidating the molecular regulation of myogenic progenitor populations has involved animal models of muscle regeneration, with questionable relevance for human muscle adaptation to exercise. This paper highlights the current state of knowledge on the molecular regulation of satellite cells, explores the potential contribution of atypical myogenic progenitors, and discusses the information gathered from animal regeneration models in terms of its relevance to the process of exercise adaptation.
Effect of different intensities of active recovery on sprint swimming performance
Authors: Toubekis Argyris G. , Smilios Ilias , Bogdanis Gregory C. , Mavridis Georgios , Tokmakidis Savvas P.
Published: January 2007

Active recovery reduces blood lactate concentration faster than passive recovery and, when the proper intensity is applied, a positive effect on performance is expected. The purpose of the study was to investigate the effect of different intensities of active recovery on performance during repeated sprint swimming. Nine male well-trained swimmers performed 8 repetitions of 25 m sprints (8 × 25 m) interspersed with 45 s intervals, followed by a 50 m sprint test 6 min later. During the 45 s and 6 min interval periods, swimmers either rested passively (PAS) or swam at an intensity corresponding to 50% (ACT50) and 60% (ACT60) of their individual 100 m velocity. Blood lactate was higher during PAS compared with ACT50 and ACT60 trials (p < 0.05), whereas plasma ammonia and glycerol concentration were not different between trials (p > 0.05). Mean performance time for the 8 × 25 m sprints was better in the PAS compared with the ACT50 and ACT60 trials (PAS: 13.10 ± 0.07 vs. ACT50: 13.43 ± 0.10 and ACT60: 13.47 ± 0.10s, p < 0.05). The first 25 m sprint was not different across trials (p > 0.05), but performance decreased after sprint 2 during active recovery trials (ACT50 and ACT60) compared with the passive recovery (PAS) trial (p < 0.05). Performance time for the 50 m sprint performed 6 min after the 8 × 25 m sprints was no different between trials (p > 0.05). These results indicate that active recovery at intensities corresponding to 50% and 60% of the 100 m velocity during repeated swimming sprints decreases performance. Active recovery reduces blood lactate concentration, but does not affect performance on a 50 m sprint when 6 min recovery is provided. Passive recovery is advised during short-interval repeated sprint training in well-trained swimmers.
Non-exhaustive test for aerobic capacity determination in swimming rats
Authors: Manchado Fúlvia de Barros , Gobatto Claudio Alexandre , Voltarelli Fabricio Azevedo , Rostom de Mello Maria Alice
Published: January 2007

The aim of this study was to describe a double-bout exercise test for non-exhaustive aerobic capacity determination in swimming rats. Adult rats were submitted to 4 swimming tests at different intensities (4%, 6%, 7%, and 8% of body mass), with intervals of 48 h between them. Two exercise bouts of equal intensity lasting 5 min were performed, separated by 2 min with blood collection for lactate analysis. For each intensity, delta lactate was determined by subtracting lactate concentration at the end of the first effort from the lactate at the end of the second effort. Individual linear interpolation of delta lactate concentration enabled determination of a “null” delta, equivalent to the critical load (CL). Maximal lactate steady state (MLSS) was also determined. The estimated CL was of 4.8% body mass and the MLSS was observed at 100% of CL, with blood lactate of 5.20 mmol/L. At 90%, blood lactate stabilized, with a progressive increase to 110% CL. These results offer a potential determination of aerobic capacity in swimming rats.
Interval training at 95% and 100% of the velocity at VO2 max: effects on aerobic physiological indexes and running performance
Authors: Denadai Benedito S , Ortiz Marcelo J , Greco Camila C , de Mello Marco T
Published: January 2007

The objective of this study was to analyze the effect of two different high-intensity interval training (HIT) programs on selected aerobic physiological indices and 1500 and 5000 m running performance in well-trained runners. The following tests were completed (n = 17): (i) incremental treadmill test to determine maximal oxygen uptake (VO2 max), running velocity associated with VO2 max (vVO2 max), and the velocity corresponding to 3.5 mmol/L of blood lactate concentration (vOBLA); (ii) submaximal constant-intensity test to determine running economy (RE); and (iii) 1500 and 5000 m time trials on a 400 m track. Runners were then randomized into 95% vVO2 max or 100% vVO2 max groups, and undertook a 4 week training program consisting of 2 HIT sessions (performed at 95% or 100% vVO2 max, respectively) and 4 submaximal run sessions per week. Runners were retested on all parameters at the completion of the training program. The VO2 max values were not different after training for both groups. There was a significant increase in post-training vVO2 max, RE, and 1500 m running performance in the 100% vVO2 max group. The vOBLA and 5000 m running performance were significantly higher after the training period for both groups. We conclude that vOBLA and 5000 m running performance can be significantly improved in well-trained runners using a 4 week training program consisting of 2 HIT sessions (performed at 95% or 100% vVO2 max) and 4 submaximal run sessions per week. However, the improvement in vVO2 max, RE, and 1500 m running performance seems to be dependent on the HIT program at 100% vVO2 max.
Transgenerational inheritance of the insulin-resistant phenotype in embryo-transferred intrauterine growth-restricted adult female rat offspring
Authors: Thamotharan Manikkavasagar , Garg Meena , Oak Shilpa , Rogers Lisa M. , Pan Gerald , Sangiorgi Frank , Lee Paul W. N. , Devaskar Sherin U.
Published: January 2007

To determine mechanisms underlying the transgenerational presence of metabolic perturbations in the intrauterine growth-restricted second-generation adult females (F2 IUGR) despite normalizing the in utero metabolic environment, we examined in vivo glucose kinetics and in vitro skeletal muscle postinsulin receptor signaling after embryo transfer of first generation (F1 IUGR) to control maternal environment. Female F2 rats, procreated by F1 pre- and postnatally nutrient- and growth-restricted (IUGR) mothers but embryo transferred to gestate in control mothers, were compared with similarly gestating age- and sex-matched control (CON) F2 progeny. Although there were no differences in birth weight or postnatal growth patterns, the F2 IUGR had increased hepatic weight, fasting hyperglycemia, hyperinsulinemia, and unsuppressed hepatic glucose production, with no change in glucose futile cycling or clearance, compared with F2 CON. These hormonal and metabolic aberrations were associated with increased skeletal muscle total GLUT4 and pAkt concentrations but decreased plasma membrane-associated GLUT4, total pPKCζ, and PKCζ enzyme activity, with no change in total SHP2 and PTP1B concentrations in IUGR F2 compared with F2 CON. We conclude that transgenerational presence of aberrant glucose/insulin metabolism and skeletal muscle insulin signaling of the adult F2 IUGR female offspring is independent of the immediate intrauterine environment, supporting nutritionally induced heritable mechanisms contributing to the epidemic of type 2 diabetes mellitus.
Stress Management at the Worksite
Authors: Lucini Daniela , Riva Silvano , Pizzinelli Paolo , Pagani Massimo
Published: January 2007

Work stress may increase cardiovascular risk either indirectly, by inducing unhealthy life styles, or directly, by affecting the autonomic nervous system and arterial pressure. We hypothesized that, before any apparent sign of disease, work-related stress is already accompanied by alterations of RR variability profile and that a simple onsite stress management program based on cognitive restructuring and relaxation training could reduce the level of stress symptoms, revert stress-related autonomic nervous system dysregulation, and lower arterial pressure. We compared 91 white-collar workers, enrolled at a time of work downsizing (hence, in a stress condition), with 79 healthy control subjects. Psychological profiles were assessed by questionnaires and autonomic nervous system regulation by spectral analysis of RR variability. We also tested a simple onsite stress management program (cognitive restructuring and relaxation training) in a subgroup of workers compared with a sham subgroup (sham program). Workers presented an elevated level of stress-related symptoms and an altered variability profile as compared with control subjects (low-frequency component of RR variability was, respectively, 65.2±2 versus 55.3±2 normalized units;
P
<0.001; opposite changes were observed for the high-frequency component). These alterations were largely reverted (low-frequency component of RR variability from 63.6±3.9 to 49.3±3 normalized units;
P
<0.001) by the stress management program, which also slightly lowered systolic arterial pressure. No changes were observed in the sham program group. This noninvasive study indicates that work stress is associated with unpleasant symptoms and with an altered autonomic profile and suggests that a stress management program could be implemented at the worksite, with possible preventive advantages for hypertension.
Myocardial Ischemic Memory Imaging With Molecular Echocardiography
Authors: Villanueva Flordeliza S. , Lu Erxiong , Bowry Shivani , Kilic Sevgi , Tom Eric , Wang Jianjun , Gretton Joan , Pacella John J. , Wagner William R.
Published: January 2007

Background—

Diagnosing acute coronary syndrome in patients presenting with chest discomfort is a challenge. Because acute myocardial ischemia/reperfusion is associated with endothelial upregulation of leukocyte adhesion molecules, which persist even after ischemia has resolved, we hypothesized that microbubbles designed to adhere to endothelial selectins would permit echocardiographic identification of recently ischemic myocardium.

Methods and Results—

Lipid microbubbles (diameter, 3.3±1.7 μm) were synthesized. The selectin ligand sialyl Lewis
x
was conjugated to the microbubble surface (MB
sLex
). Control bubbles (MB
CTL
) bore surface Lewis
x
or sialyl Lewis
c
. Intravital microscopy of mouse cremaster muscle was performed after intravenous injection of MB
sLex
(n=11) or MB
CTL
(n=9) with or without prior intrascrotal tumor necrosis factor–α. There was greater adhesion of MB
sLex
to inflamed versus noninflamed endothelium (
P
=0.0081). Rats (n=12) underwent 15 minutes of anterior descending coronary artery occlusion. After 30 minutes and 1 hour of reperfusion, high-mechanical-index nonlinear echocardiographic imaging was performed in which single frames were acquired at 3.5 and 4 minutes after intravenous injection of MB
sLex
or MB
CTL
. Video intensity at 4 minutes was subtracted from that at 3.5 minutes to derive target-specific acoustic signal. MB
sLex
caused greater opacification in postischemic versus nonischemic myocardium at both time points (
P
≤0.002). Immunostaining confirmed endothelial P-selectin expression in the ischemic bed.

Conclusions—

Echocardiographic identification of recently ischemic myocardium is possible using ultrasound contrast agents targeted to selectins. This may offer a new approach to the more timely and precise diagnosis of acute coronary syndrome in patients presenting with chest pain of uncertain cardiac origin.
Bachelard's Subversive Hermeneutics: A Reading of "Lightning "in Shelley's Prometheus Unbound
Authors: Rizo-Patron Eileen
Published: January 2007

The purpose of this piece is to probe the nature of Bachelard's subversive hermeneutics by focusing on his predilection for those often unsettling poetic intuitions which emerge with the force of a summons in the experience of reading. My wager is that the hermeneutics of literary texts proposed by Gaston Bachelard in The Poetics of Space (1957) has its antecedents in his polemical theory of "discontinuous time" and the accompanying "pedagogy of discontinuity" set forth in his early work L'Intuition de l'instant: essai sur la Siloé de Gaston Roupnel (1932). The task of this hermeneutics, epitomized by Bachelard's own reading of Siloé, is to detect the ruptures, burning questions, or surprising insights that spark and (re)orient the movement of our life projects, with a view to unfolding the ethical implications of the "call of an instant" upon our sense of intimate duration and history. In the second half of this essay I proceed to set this hermeneutics into motion through a reading of Shelley's Prometheus Unbound that focuses on "lightning" as an image of Bachelardian "instants" in this drama—critical moments charged with contradictions that ultimately seem to steer the poet's course in directions, or towards ethical possibilities, other than his controlling artistic will could have charted out in advance.
The "Logic of Metaphor" at Work: Hart Crane's Marian Metaphor in the Bridge
Authors: Wargacki John
Published: January 2007

This essay explores Hart Crane's transformation of the figure of the Mother of God from its traditional Catholic dimension to an empowering spiritual presence redefined and re-examined according to Crane's ambitious aesthetic designs. While many key figures in The Bridge—from Columbus to Whitman to Williams and Cummings—have garnered ample critical attention, the Marian aspect so central to the poem has been all but neglected. Yet the evidence indicates that, as an iconic force, Mary is as important to the poem as the New World figure of Pocahontas in that she supplies an essential mythic presence for a project that aspires to nothing less than lending "a myth to God."I argue that Crane, via his "Logic of Metaphor," has shrewdly transformed the Mary figure at key moments throughout the text, from the proem to "Virginia," making her role, along with that of Pocahontas, an integral feature of this rich and vibrant contribution to American poetry.
Joint Development: An Alternative Legal Approach to Oil and Gas Exploitation in the Nigeria-Cameroon Maritime Boundary Dispute?
Authors: Okafor Chidinma Bernadine
Published: January 2007

The delimitation of a maritime boundary is not necessarily a panacea for disputes over offshore resources. Neither petroleum reserves, which are fugacious in character, nor fish or marine mammals respect national boundaries. Even successful delimitation may still require a degree of close cooperation if opposite or adjacent states are to exploit such transboundary resources rationally. Such cooperation can be achieved by the concept of joint development. This paper reviews the literature on the joint development of offshore petroleum resources and the controversy surrounding the concept. The paper further examines its applicability as an alternative approach to the Nigeria-Cameroon maritime boundary dispute.
Outer Limits of the Continental Shelf and "Disputed Areas": State Practice concerning Article 76(10) of the LOS Convention
Authors: Johnson Constance , Oude Elferink Alex
Published: January 2007

Article 76 of the United Nations Convention on the Law of the Sea (LOS Convention) requires a coastal State to submit information on the limits of its continental shelf beyond 200 nautical miles to the Commission on the Limits of the Continental Shelf (CLCS). The Commission shall make recommendations to the coastal State on matters related to the establishment of the outer limits of the continental shelf. In a case where the coastal State establishes the outer limits on the basis of these recommendations, they are final and binding. However, Article 76(10) provides that the "The provisions of this article are without prejudice to the question of delimitation of the continental shelf between States with opposite or adjacent coasts". The relationship between Article 76 and the delimitation of the continental shelf between neighboring States and other "unresolved land or maritime disputes" has been addressed by the CLCS in its Rules of Procedure. The present article analyzes the significance of Article 76(10) for submissions to the CLCS, looking at the Rules of Procedure of the Commission and the submissions that have been made to the Commission to date.
Interval Estimates of Multivariate Effect Sizes
Authors: Hess Melinda R. , Hogarty Kristine Y. , Ferron John M. , Kromrey Jeffrey D.
Published: January 2007

Monte Carlo methods were used to examine techniques for constructing confidence intervals around multivariate effect sizes. Using interval inversion and bootstrapping methods, confidence intervals were constructed around the standard estimate of Mahalanobis distance ( D2), two bias-adjusted estimates of D2, and Huberty’s I. Interval coverage and width were examined across conditions by adjusting sample size, number of variables, population effect size, population distribution shape, and the covariance structure. The accuracy and precision of the intervals varied considerably across methods and conditions; however, the interval inversion approach appears to be promising for D2, whereas the percentile bootstrap approach is recommended for the other effect size measures. The results imply that it is possible to obtain fairly accurate coverage estimates for multivariate effect sizes. However, interval width estimates tended to be large and uninformative, suggesting that future efforts might focus on investigating design factors that facilitate more precise estimates of multivariate effect sizes.
Empirical Histograms in Item Response Theory With Ordinal Data
Authors: Woods Carol M.
Published: January 2007

The purpose of this research is to describe, test, and illustrate a new implementation of the empirical histogram (EH) method for ordinal items. The EH method involves the estimation of item response model parameters simultaneously with the approximation of the distribution of the random latent variable (τ) as a histogram. Software for the EH method with ordinal items (having more than two response options) has not been readily available in the past but was created for the present research. Simulation results suggest that with larger (but not smaller) numbers of quadrature points, graded-model item parameter estimates from the EH method are highly accurate when the τ distribution is either normal or skewed. Results for expected a posteriori scores depend on the magnitude of τ.
Mutual Information Item Selection in Adaptive Classification Testing
Authors: Weissman Alexander
Published: January 2007

A general approach for item selection in adaptive multiple-category classification tests is provided. The approach uses mutual information (MI), a special case of the Kullback-Leibler distance, or relative entropy. MI works efficiently with the sequential probability ratio test and alleviates the difficulties encountered with using other local- and global-information measures in the multiple-category classification setting. Results from simulation studies using three item selection methods, Fisher information (FI), posterior-weighted FI (FIP), and MI, are provided for an adaptive four-category classification test. Both across and within the four classification categories, it is shown that in general, MI item selection classifies the highest proportion of examinees correctly and yields the shortest test lengths. The next best performance is observed for FIP item selection, followed by FI.
A Psychometric Investigation of the Academic Self-Concept of Asian American College Students
Authors: Cokley Kevin , Patel Nima
Published: January 2007

The psychometric properties of scores from the Academic Self-Concept Scale are examined in a group of 198 Asian American college students. Using parallel analysis, a four-factor solution accounting for 46% of the variance was found. In a test of construct validity, academic self-concept was found to be negatively related to adherence to Asian values, positively related to adherence to European American values, and positively related to grade point average. Results suggest that academic self-concept, as currently measured, is primarily an individualistic psychological construct.
Extending Improvement-Over-Chance I-Index Effect Size Simulation Studies to Cover Some Small-Sample Cases
Authors: Natesan Prathiba , Thompson Bruce
Published: January 2007

All effect sizes are sensitive to design flaws and the failure to meet analytic assumptions. But some effect sizes appear to be more robust to assumption violations (e.g., homogeneity of variance). The present study extended prior Monte Carlo research by exploring the robustness of group overlap I indices at the relatively small sample sizes used in some research. I effects are statistically appealing because these indices can be applied across (a) both univariate and multivariate analyses and (b) conditions of either variance homogeneity or variance heterogeneity.
Experimental Analysis of Question Wording in an Instrument Measuring Teachers’ Attitudes Toward Inclusive Education
Authors: Dedrick Robert F. , Marfo Kofi , Harris Deborah M.
Published: January 2007

An experimental study ( n = 288 general and special education teachers) examining the effects of altering the referent (“students with mild disabilities,” “students with severe disabilities,” or “students with disabilities”) on a four-item scale (Negative Effect of Inclusion) indicated that wording changes had little effect on the scale’s psychometric properties (e.g., factor pattern coefficients). Changes did result in a shift in the mean level of the attitude scale. Regression coefficients between the scale and type of teacher, total years of teaching experience, years of experience at current school, and training in inclusion were not significantly altered by changing the referent. Gender was the only predictor that exhibited a lack of invariance in its regression coefficients across questionnaire forms that differed in referent. For most of the bivariate relationships examined in this study, the same conclusions would be drawn no matter which of the three referents were used.