bluuebunny/crossref_metadata_2025 huggingface dataset:
Validity of cycling peak power as measured by a short-sprint test versus the Wingate anaerobic test
Authors: Coso Juan Del , Mora-Rodríguez Ricardo
Published: June 2006

To validate the measurement of peak power output (PPO) using a short cycling sprint test (inertial load (IL) test), we compare it to the widely accepted Wingate anaerobic test (WAnT). Fifteen healthy, young, active subjects performed 2 experimental trials. In each trial, subjects warmed up and sprinted 4 times for the IL test. After recovery, they cycled for 30 s at maximum capacity for the WAnT. The experimental trial was replicated 3 d later to test for reliability. Inter- and intra-day PPO measured with the IL test was very reliable (R1 = 0.99 and R1 = 0.94, respectively). The correlation between the IL and WAnT was highly significant (r = 0.82; P < 0.001), although the absolute PPO values were markedly higher for the IL test (1268 ± 41 W vs. 786 ± 27 W; P < 0.001). In conclusion, cycling PPO can be validly assessed with the IL test. The higher PPO attained with an IL test could be related to better identification of peak power, since both velocity and resistance are free to vary during the sprint in comparison with the WAnT, where resistance is fixed. Owing to the short duration of the sprint (4 s) and high intra-day reliability despite a short recovery time (180 s), the IL test is optimal for repeated measurements of anaerobic performance.Key words: inertial load, neuromuscular power, cycle ergometer, intra-day reliability, performance.
Comparison between old and young men for changes in makers of muscle damage following voluntary eccentric exercise of the elbow flexors
Authors: Lavender Andrew P , Nosaka Kazunori
Published: June 2006

This study aimed to investigate if old men were more susceptible than young men to muscle damage induced by exercise consisting of repeated-lengthening muscle actions. The responses to a bout of eccentric exercise were compared between 10 young (mean age ± SEM = 19.4 ± 0.4 y) and 10 old (70.5 ± 1.5 y) men. All subjects performed 6 sets of 5 lengthening actions of the left elbow flexors at a range of 90° from an elbow flexed (90°) to an extended (180°) position in 5 s using a dumbbell massed at 40% maximal isometric strength (MVC) at an elbow joint angle of 90°. Changes in MVC, range of motion (ROM), upper arm circumference (CIR), muscle soreness (DOMS), plasma creatine kinase activity (CK), and myoglobin (Mb) concentration over 7-10 d following exercise were compared between groups by 2-way repeated measures analysis of variance (ANOVA). Significant differences between groups were evident at baseline for ROM (significantly smaller for the older group) and CIR (significantly larger for the older group), but not for MVC and other measures. Contrary to the hypothesis, the young group showed significantly larger decreases in MVC and ROM and larger increases in circumference, DOMS, CK activity, and Mb con centration than those of the old group. These results suggest that muscle damage is not necessarily greater in old versus young men following voluntary eccentric exercise. It may be that physiological changes that occur with ageing, including a decrease in ROM, reduce damaging stress to muscles during lengthening muscle actions.Key words: ageing, maximal isometric strength, muscle soreness, creatine kinase, myoglobin.
Effects of resuming endurance training on arterial stiffness and nitric oxide production during exercise in elite cyclists
Authors: Tordi Nicolas , Colin Eglantine , Mourot Laurent , Bouhaddi Malika , Regnard Jacques , Laurant Pascal
Published: June 2006

Exercise training improves arterial compliance due to increases in blood flow to skeletal muscle during repeated bouts of daily exercise. The effect of resuming training on arterial stiffness in previously well-trained subjects is poorly documented. Hence, the purpose of this study was to determine the vascular effects induced by return to exercise in highly trained cyclists. Pulse wave velocity (PWV), an index of arterial stiffness, was assessed at rest and during constant moderate-intensity cycle exercises before and after 16 weeks of endurance training. The impact of daily exercise on the concentration of nitric oxide (NO) measured as nitrate in plasma was examined at rest and during maximal exercise before and after the training period. At rest, PWV was significantly lower in the subjects after a training session (6.4 ± 0.4 vs. 8.1 ± 0.4 m·s-1, p < 0.05). During constant exercise, PWV was significantly and positively correlated with increases in blood pressure. The increased PWV induced by exercise was, however, significantly lower after training (9.8 ± 0.6 vs. 11.4 ± 0.6 m·s-1, p < 0.05). After the training program, nitrate plasma levels at rest were higher. During the maximal test, the plasma nitrate concentration was increased in the subjects studied before the training period, but not after. These results show that resumption of chronic endurance training rapidly induces adaptive changes in arterial stiffness and NO release that may contribute to improved physical fitness in athletes.Key words: exercise, trained subjects, pulse wave velocity, nitrate, arteries.
Independent effects of waist circumference and physical activity on all-cause mortality in Canadian women
Authors: Katzmarzyk Peter T , Craig Cora L
Published: June 2006

The purpose of this study was to determine the independent effects of waist circumference (WC) and physical inactivity on the risk of mortality in women. This prospective cohort study included 5421 female participants 20-69 years of age in the 1981 Canada Fitness Survey. WC was measured with an anthropometric tape and leisure-time physical activity levels over the previous 12 months were assessed with a questionnaire. Mortality surveillance was conducted by data linkage with the Canadian Mortality Database through 31 December, 1993. The hazard ratios (HR) of mortality were estimated using Cox proportional hazards regression with age, smoking status, and alcohol con sumption included as covariates in all models. A total of 225 deaths occurred over an average of 12.4 years of follow up (67 500 person-years of follow up). Physical activity (HR = 0.78; 95% C.I.: 0.64-0.95) and WC (HR = 1.17; 95% C.I.: 1.05-1.31) were associated with mortality when included in separate regression models. When included in the same model, both physical activity (HR = 0.79; 95% CI: 0.65-0.96) and WC (HR = 1.16; 95% C.I.: 1.04-1.30) remained independent significant predictors of mortality. In conclusion, physical inactivity and high WC have significant independent risks of premature mortality among women.Key words: death, obesity, cohort study, Canada Fitness Survey.
Influence of crank rate on the slow component of pulmonary O2 uptake during heavy arm-crank exercise
Authors: Smith Paul M , McCrindle Eilidh , Doherty Mike , Price Michael J , Jones Andrew M
Published: June 2006

The principal aim of this study was to examine the influence of variations in crank rate on the slow component of the pulmonary oxygen uptake ([Formula: see text]O2) response to heavy-intensity arm-crank ergometry (ACE). We hypothesized that, for the same external work rate, a higher crank rate would elicit a greater amplitude of the [Formula: see text]O2 "slow component". Eleven healthy males (mean (± SD) age, 25 (±6) y; body mass, 89.1 (±10.7) kg; ACE [Formula: see text]O2 peak, 3.36 (±0.47) L·min-1) volunteered to participate. The subjects initially completed an incremental exercise test for the determination of [Formula: see text]O2 peak and peak power on an electrically braked arm ergometer. Subsequently, they completed "step" transitions from an unloaded baseline to a work rate requiring 70% of peak power: 2 at a crank rate of 50 r·min-1 (LO) and 2 at a crank rate of 90 r·min-1 (HI). Pulmonary gas exchange was measured on a breath-by-breath basis and [Formula: see text]O2 kinetics were evaluated from the mean response to each condition using non-linear regression techniques. In contradiction to our hypothesis, the [Formula: see text]O2 slow component was significantly greater at 50 r·min-1 than at 90 r·min-1 (LO: 0.60 ± 0.30 vs. HI: 0.47 ± 0.21 L·min-1; p < 0.05). The mean value for the localized rating of perceived exertion was also higher at 50 r·min-1 than at 90 r·min-1 (LO: 16.7 ± 1.4 vs. HI: 15.2 ± 1.3; p < 0.05), but there was no significant difference in end-exercise blood lactate concentration. It is possible that differences in muscle tension development and blood flow resulted in a greater contribution of "low-efficiency" type II muscle fibres to force production at the lower crank rate in ACE, and that this was linked to the greater [Formula: see text]O2 slow component. However, other factors such as greater isometric contraction of the muscles of the trunk and legs at the lower crank rate might also be implicated.Key words: O2 kinetics, [Formula: see text]O2 slow component, fibre recruitment, oxygen uptake.
Is isometric strength loss immediately after eccentric exercise related to changes in indirect markers of muscle damage?
Authors: Nosaka Kazunori , Chapman Dale , Newton Mike , Sacco Paul
Published: June 2006

This study tested the hypothesis that the magnitude of maximal isometric strength (MVC) loss immediately following eccentric exercise (MVC-post) would relate to changes in other indirect markers of muscle damage following exercise. Eighty-nine men were recruited from the same student population and performed 24 maximal eccentric actions of the elbow flexors. Commonly used markers of muscle damage such as relaxed and flexed elbow joint angles, range of motion (ROM), upper-arm circumference, muscle soreness, and plasma creatine kinase (CK) activity were measured before, immediately after, and 1-4 d after exercise. Pearson's product-moment correlation coefficients (r) between change in MVC-post and other markers of muscle damage, as well as MVC during recovery days, were calculated. Changes in MVC-post ranged from -72.8% to -17.6%, and correlated significantly (p < 0.01) with MVC at 1 (r = 0.59), 2 (0.63), 3 (0.61), and 4 (0.62) d after exercise. Reduction in MVC-post also correlated significantly (p < 0.05) with changes in relaxed (r = 0.50) and flexed elbow joint angles (-0.40), ROM (0.55), arm circumference (-0.45), peak palpation (-0.34) and extension muscle soreness (-0.48), and peak CK activity (-0.59). However, the r values were not necessarily high, and MVC-post poorly reflected the distribution of some measures, such as peak CK activity (124 - 50 440 IU·L-1). These results suggest that MVC-post is not a strong correlate of the changes in markers of muscle damage following eccentric exercise of the elbow flexors.Key words: maximal isometric strength, plasma CK activity, ROM, swelling, muscle soreness.
DEVELOPMENT OF REGIONAL PIXE FACILITY AT PANJAB UNIVERSITY CYCLOTRON, CHANDIGARH (INDIA)
Authors: PURI N. K. , BALOURIA P. , GOVIL I. M. , MOHANTY B. P. , GARG M. L.
Published: June 2006

A description of modifications in the variable energy cyclotron (VEC) Chandigarh along with the installation of Proton Induced X-ray Emission (PIXE) setup is presented. A new main magnet power supply of 400A/125V out put with ±10 ppm stability and a new stabilized solid state power supply for RF oscillator has improved the beam characteristics substantially. A new chamber has been designed to cater for Proton Induced Gamma Emission (PIGE) and Rutherford Back Scattering (RBS) along with PIXE measurements. The HPGe x-ray detector, the Ge(Li) γ-ray detector and a silicon surface barrier (SSB) detector can be mounted simultaneously in the chamber for this purpose. A Turbo-Molecular vacuum pump is provided to produce a clean vacuum of the order of 10-8mbar in the PIXE chamber. A remotely controlled stepper motor is provided to move the wheel having 12/24-position target holder. Beam size optimization along with the minimization of background has been done with the help of graphite collimators, thus making the setup suitable for practical applications. Preliminary experiments for the PIXE analysis of aerosol, gunshot residues and kidney stone samples are presented.
MEASUREMENT OF TRACE METALS IN THYROID NODULES IN IRAN BY PIXE
Authors: MOOSAVI K. , VATANKHAH S. , SALIMI J.
Published: June 2006

A PIXE (Proton Induced X-ray Emission) analysis is applied for measuring the concentration of 21 major and minor trace metal elements (in the range of Z =13-53) for normal, adenoma and carcinoma human thyroid tissues. A 2.0 MeV proton beam was employed to excite the samples. The thyroid samples were obtained from 14 patients during surgical operations, with which normal and damaged parts are concerned as an aid to understand the mechanisms of formation of thyroid cancer and as a complementary diagnostic tool. Thirty samples were measured in total. Fourteen samples of them were in pairs, i.e.14 tumor samples with 14 corresponding healthy tissue specimens taken at a distance from the tumor. The statistical analysis of the results shows the lower levels of the mean value of iron and iodine in the carcinoma tissues than those in the normal tissues; especially iodine is about one tenth of the normal value. On the contrary, the elevation of the mean value for calcium and zinc in the carcinoma tissues in comparison with the normal ones is observed, while in the adenoma tissues copper is very lower than those in the normal thyroid. The concentration of iron in the adenoma is two times of normal tissues.
PARTICLE INDUCED X-RAY EMISSION STUDIES OF ANTI-DIABETIC MEDICINAL PLANTS
Authors: RAY D. K. , NAYAK P. K. , PANDA S. R. , RAUTRAY T. R. , VIJAYAN V. , CHRISTOPHER C. C. , JENA S.
Published: June 2006

Selected number of anti-diabetic medicinal plant leaves has been characterized by accelerator based particle-induced X-ray emission (PIXE) technique. Validity of the technique was assured by analyzing certified plant reference materials (CRMs). A large number of trace elements like Ti , V , Cr , Mn , Fe , Co , Ni , Cu , Zn , Rb , Sr and Pb are found to be present in these studied leaf samples with variable proportions. The concentrations of elements like K and Ca are quantified in percentage level whereas other elements are found to be in parts per million levels. Among the studied samples, the leaves of Methi are found to be containing maximum amount of trace elements.
A STUDY ON THE RELATIONSHIP BETWEEN HELICOBACTER PYLORI AND TRACE ELEMENTS IN GASTRIC MUCOSA
Authors: FUKUDA T. , SAKURAI S. , KUDO M.
Published: June 2006

H2 receptor antagonist (H2RA) and proton pump inhibitor(PPI) are often used to treat gastric ulcers, in addition to the zinc-L-carcino-complex which is commonly adopted for such therapies. However, there have been no previous reports detailing the levels and distribution of zinc in human gastric mucosa. The aim of our current study is to clarify the relationship between Helicobacter pylori infection and trace elements such as zinc in gastric mucosa using particle induced X-ray emission (PIXE). Forty gastric ulcer patients were chosen as subjects of this study and divided into two groups. One is a new ulcer patients group(twenty nine cases). And the other, eleven of these patients had been prescribed zinc-L-carcino-complex (polapreZinc®), at a dose of 150mg/day for periods ranging from 16 to 20 weeks. The zinc levels in the gastric ulcer group were found to be significantly less than those of the control group and the concentrations of zinc in gastric mucosa were observed to increase following the administration of treatments containing this element.
RESEARCH OF DISEASE ONSET MECHANISM BY DETERMINING THE DISTRIBUTION OF INTRACELLULAR TRACE ELEMENTS USING AN IN-AIR MICRO-PIXE ANALYZER SYSTEM
Authors: NAKANO TAKASHI , ARAKAWA KAZUO , SAKURAI HIDEYUKI , HASEGAWA MASATOSHI , YUASA KAZUHISA , SAITO ETSUKO , TAKAGI HITOSHI , NAGAMINE TAKEAKI , KUSAKABE TAKAHIKO , TAKADA HISASHI , NAKAZATO KYOUMI , SUZUKI KEIJI , KAMIYA TOMIHIRO , SATOH TAKAHIRO , OIKAWA MASAKAZU , SAKAI TAKURO
Published: June 2006

A program was started to create a new medical scientific field, which involves radiation oncology and nuclear medicine, utilizing advanced accelerator and ion beam technology. An in-air micro-PIXE analyzer system, which is among the most important technical aspects of the program, was upgraded to improve the accuracy of elemental mapping for samples with thickness variation in the scope of microbeam scanning. In order to address important bio-medical problems in cancer, the intracellular dynamics of trace elements according to the development mechanism of diseases were studied using this system. This paper outlines the program, showing correction of micro-PIXE elemental map by STIM analysis and the preliminary application results.
DETERMINATION OF TRACE ELEMENTS IN EUGLENA GRACILISZ AND ITS BLEACHED MUTANT STRAINS
Authors: ISHII NOBUYOSHI , KOISO HIROYUKI , SAKASHITA TETSUYA , FUMA SHOICHI , TAKEDA HIROSHI , UCHIDA SHIGEO
Published: June 2006

Two types of bleached mutant strains were isolated from a culture of wild-type Euglena gracilis Z strain. These mutant strains formed yellow and white colored colonies, named Y 1 ZSmL and W 1 ZSmL , respectively. The losses of chlorophyll a in both mutant strains were found from the evaluation of chlorophyll a concentrations. To elucidate physiological effects due to the chlorophyll a loss, cell growth and the amounts of trace elements ( Al , P , S , K , Ca , Fe , Cu , and Zn ) in each strain were studied. The obtained data for mutant strains were compared with those for wild-type Z strain. Cell growth of each strain differed and the abundances of cells were consequently high, decreasing in the order of Z , Y 1 ZSmL , and W 1 ZSmL . The amounts of all elements except S in mutant strains were significantly lower than those in the Z strain. Differences between Y 1 ZSmL and W 1 ZSmL were found only in the amount of Cu . Copper, therefore, would be one of the factors causing differences in the color of the colonies and the growth of cells between both mutant strains.
APPLICATION OF PIXE FOR A MULTI-ELEMENT ANALYSIS OF MARINE PHYTOPLANKTON TOWARDS THE DEVELOPMENT OF A NEW BIOLOGICAL ASSESSMENT METHOD FOR HEAVY METAL POLLUTION
Authors: SATOH A. , SEKIGUCHI H. , KURANO N. , MIYACHI S. , SERA K. , IWATA Y.
Published: June 2006

Particle-induced X-ray emission (PIXE) was applied for the determination of heavy metals accumulated in natural phytoplankton. We selected four Japanese marine sites to collect phytoplankton: Toni Bay and Kamaishi Bay (Kamaishi, Iwate) as non-polluted areas; and Shimotsu port (Shimotsu, Wakayama) and Toyama new port (Shinminato, Toyama) as polluted areas. After removing the zooplankton and visible dust by passing the seawater through an NXX13 plankton net (95-μm mesh aperture), the phytoplankton were collected on a polycarbonate filter (25 mm diameter, 1.0 μm pore size) by suction filtration. The filter was dried and subjected to scanning electron microscopy (SEM) and a PIXE analysis. The phytoplankton consisted of diatoms, dinoflagellates and coccolithophores were observed by SEM analysis on the filter prepared from 100 ml of Toni Bay seawater. Heavy metals ( Pb , Ni , Cu , Cr , Zn , Mn , Hg and As ) could be detected by the PIXE analysis in almost all the cases tested, in which 50-200 ml each of respective seawater sample was filtered. There was a linear relationship between the amount of heavy metals on the polycarbonate filter (ng cm-2) and the volume of seawater (25-200 ml) filtered (i.e. the amount of phytoplankton collected on the filter). Likewise, the PIXE analysis revealed that significant differences in heavy metal contamination between the polluted and non-polluted areas, and also among sampling sites in a polluted area depending on the location and seawater movement. These results indicate that a multi-element analysis of marine phytoplankton by PIXE would be a promising technique for biologically assessing and monitoring heavy metal pollution in the first link of the aquatic food chain.
PIXE ANALYSIS AND COMPARISION OF AEROSOL SAMPLES FROM RELATIVELY CLEAN AND INDUSTRIALLY POLLUTED CITIES IN NORTHEN INDIA
Authors: BALOURIA P. , GOVIL I. M. , MOHANTY B. P. , GARG M. L. , KUMAR R. , RAINA A.
Published: June 2006

Particle induced X-ray emission (PIXE) technique developed at Variable Energy Cyclotron, Panjab University Chandigarh has been used for the detection of trace elements in the aerosol samples collected from relatively clean and industrially polluted city in northern India. Aerosol samples were collected from Jammu City of Jammu and Kashmir State, which is supposed to have a clean environment and from Mandi-Gobindgarh, one of the most polluted steel city of Punjab. The results from the analysis of these samples show some basic differences in the trace element profile of the two cities. The results further suggest a long term aerosol sample analysis to segregate anthropogenic and natural sources of air pollution. The mean concentration levels of different trace elements in PM10(Particulate matter with aerodynamic diameter less than 10 μm) from these two cities of northern India are compared with some of the prominent cities of India.
INVARIANT DENSITIES FOR POSITION-DEPENDENT RANDOM MAPS ON THE REAL LINE: EXISTENCE, APPROXIMATION AND ERROR BOUNDS
Authors: BAHSOUN WAEL , GÓRA PAWEŁ
Published: June 2006

A random map is a discrete-time dynamical system in which a transformation is randomly selected from a collection of transformations according to a probability function and applied to the process. In this note, we study random maps with position-dependent probabilities on ℝ. This means that the random map under consideration consists of transformations which are piecewise monotonic with countable number of branches from ℝ into itself and a probability function which is position dependent. We prove existence of absolutely continuous invariant probability measures and construct a method for approximating their densities. Explicit quantitative bound on the approximation error is given.
MARTINGALE APPROXIMATION OF NON-STATIONARY STOCHASTIC PROCESSES
Authors: VOLNÝ DALIBOR
Published: June 2006

We generalise the martingale-coboundary representation of discrete time stochastic processes to the non-stationary case and to random variables in Orlicz spaces. Related limit theorems (CLT, invariance principle, log–log law, probabilities of large deviations) are studied.
ON THE REPLICATOR DYNAMICS BEHAVIOR UNDER STRATONOVICH TYPE RANDOM PERTURBATIONS
Authors: KHASMINSKII R. , POTSEPUN N.
Published: June 2006

This paper studies the behavior of replicator dynamics systems under White Gaussian Noise (WGN) perturbations in the Stratonovich form. Long-run behavior is described for the system with two pure strategies. The method of Lyapunov functions is used to find the sufficient conditions for asymptotic stability and strong instability of the pure strategies for the system with arbitrary number of pure strategies. Extinction of strictly dominated pure strategies is proven for any level of the noises.
BAYES' FORMULA FOR SECOND QUANTIZATION OPERATORS
Authors: LANCONELLI ALBERTO
Published: June 2006

The Bayes' formula provides the relationship between conditional expectations with respect to absolutely continuous measures. The conditional expectation is in the context of the Wiener space — an example of second quantization operator. In this note we obtain a formula that generalizes the above-mentioned Bayes' rule to general second quantization operators.
THE LIE ALGEBRA STRUCTURE ON THE FIRST HOCHSCHILD COHOMOLOGY GROUP OF A MONOMIAL ALGEBRA
Authors: STRAMETZ CLAUDIA
Published: June 2006

We study the Lie algebra structure of the first Hochschild cohomology group of a finite dimensional monomial algebra Λ, in terms of the combinatorics of its quiver, in any characteristic. This allows us also to examine the identity component of the algebraic group of outer automorphisms of Λ in characteristic zero. Criteria for the (semi-)simplicity, the solvability, the reductivity, the commutativity and the nilpotency are given.
THE AMITSUR–LEVITZKI THEOREM FOR THE ORTHOSYMPLECTIC LIE SUPERALGEBRA 𝔬𝔰𝔭(1, 2n)
Authors: GIÉ PIERRE-ALEXANDRE , PINCZON GEORGES , USHIROBIRA ROSANE
Published: June 2006

Based on Kostant's cohomological interpretation of the Amitsur–Levitzki theorem, we prove a super version of this theorem for the Lie superalgebras 𝔬𝔰𝔭(1, 2n). We conjecture that no other classical Lie superalgebra can satisfy an Amitsur–Levitzki type super identity. We show several (super) identities for the standard super polynomials. Finally, a combinatorial conjecture on the standard skew supersymmetric polynomials is stated.
IWASAWA DECOMPOSITION OF THE LIE SUPERGROUP SL(n,m,ℂ)
Authors: PELLEGRINI F.
Published: June 2006

We show that the superanalogue of the Iwasawa decomposition exists for supergroup SL(n,m,ℂ). The first component of the decomposition is the compact real form SU(n,m), which was constructed following the idea of our article [3]. The second component is the super version of the AN group, that we define in this article.
Intracellular heterogeneity in adhesiveness of endothelium affects early steps in leukocyte adhesion
Authors: Mundhekar Ameya N. , Bullard Daniel C. , Kucik Dennis F.
Published: June 2006

Endothelial cell junctions are thought to be preferential sites for transmigration. However, the factors that determine the site of transmigration are not well defined. Our data show that the preferential role of endothelial cell junctions is not limited to transmigration but extends to earlier steps of leukocyte recruitment, such as rolling and arrest. We used primary mouse neutrophils and mouse aortic endothelium in a flow chamber system to compare adhesive interactions near endothelial cell junctions to interactions over endothelial cell centers. We found differences in both rolling velocity and arrest frequency for neutrophils at endothelial cell junctions vs. more central areas of endothelial cells. Differences were governed by adhesion molecule interactions, not local topography. Interestingly, the role of particular adhesion molecules depended on their location on the endothelial cell surface. Although ICAM-1 stabilized and slowed rolling over central areas of the cell, it did not influence rolling velocity over endothelial cell junctions. P-selectin and VCAM-1 were more important for rolling near endothelial cell junctions than E-selectin. This demonstrates that adhesive properties of endothelial cell junctions influence early events in the adhesion cascade, which may help explain how leukocytes are localized to sites of eventual transmigration.
Impact of bile duct obstruction on hepaticE. coliinfection: role of IL-10
Authors: Jeyarajah D. Rohan , Kielar Mariusz L. , Saboorian Hoosein , Karimi Prameela , Frantz Nicole , Lu Christopher Y.
Published: June 2006

Biliary obstruction in the setting of hepatic bacterial infection has great morbidity and mortality. We developed a novel murine model to examine the effect of biliary obstruction on the clearance of hepatic Escherichia coli infection. This model may allow us to test the hypothesis that biliary obstruction itself adversely affects clearance of hepatic infections even if the bacteria are introduced into the liver by a nonbiliary route. We ligated the bile ducts of C57BL/6 mice on days − 1, 0, or + 1, relative to a day 0 portal venous injection of E. coli. We monitored survival, hepatic bacterial growth, pathology, and IL-10 protein levels. The role of IL-10 in this model was further examined using IL-10 knockout mice. Mice with bile duct ligation at day +1 or 0, relative to portal venous infection at day 0, had decreased survival compared with mice with only portal venous infection. The impaired survival was associated with greater hepatic bacterial growth, hepatic necrosis, and increased production of IL-10. Interestingly, the transgenic knockout of IL-10 resulted in impaired survival in mice with bile duct ligation and portal venous infection. Biliary obstruction had a dramatic detrimental effect on hepatic clearance of portal venous E. coli infection. This impaired clearance is associated with increased IL-10 production. However, transgenic knockout of IL-10 increased mortality after hepatic infection.
The emergence of ErbB2 expression in cultured rat hepatocytes correlates with enhanced and diversified EGF-mediated signaling
Authors: Scheving Lawrence A. , Zhang Linda , Stevenson Mary C. , Kwak Eun Soo , Russell William E.
Published: June 2006

The proliferative effects of EGF in liver have been extensively investigated in cultured hepatocytes. We studied the effects of EGF, insulin, and other growth regulators on the expression, interaction, and signaling of ErbB receptors in primary cultures of adult rat hepatocytes. Using immunological methods and ErbB tyrosine kinase inhibitors, we analyzed the expression and signaling patterns of the ErbB kinases over 120 h of culture. Basal and EGF-stimulated protein tyrosine phosphorylation increased as cells adapted in vitro. EGF receptor (EGFr) expression declined in the first 24 h, whereas ErbB3 expression rose. Although ErbB2 was not present in freshly isolated hepatocytes, EGF and insulin independently induced ErbB2 while suppressing ErbB3 expression. Low concentrations of EGF and insulin synergistically stimulated ErbB2 expression and DNA synthesis. The greatest increase in ErbB2, which is normally expressed by fetal and neonatal hepatocytes, occurred shortly before the onset of DNA synthesis (>40 h). EGF promoted EGFr and ErbB2 coassociation, stimulating tyrosine phosphorylation of both proteins. In contrast, heregulin β1(HRG-β1) did not promote ErbB2 and ErbB3 coassociation. A selective tyrphostin inhibitor of ErbB2 suppressed EGF-stimulated DNA synthesis, but maximum suppression required the blockade of the EGFr kinase as well. Maximal EGF stimulation of DNA synthesis in vitro depends on the induction of ErbB2 and involves an EGFr-ErbB2 heterodimer. The ability of insulin to induce ErbB2 suggests both a mechanism for the synergy between insulin and EGF and a possible metabolic control of ErbB2 in vivo.
Hepatic progenitor cells in human fetal liver express the oval cell marker Thy-1
Authors: Masson Neil M. , Currie Ian S. , Terrace John D. , Garden O. James , Parks Rowan W. , Ross James A.
Published: June 2006

Hepatic progenitor cells play a major role in regenerating diseased liver. In rodents, progenitors forming hepatocytes or cholangiocytes are identified by the stem cell marker Thy-1. The aim of this study was to ascertain whether progenitor cells expressing Thy-1 could be identified in human fetal liver. Midtrimester human fetal liver was immunostained for Thy-1, cytokeratins 18 and 19, vimentin, CD34, CD45, and fibrinogen. Thy-1+and Thy-1+CD34+populations were purified using fluorescence-activated cell sorting (FACS). Immunofluorescence and mRNA expression were used to examine the bipotential nature of purified stem cells. We found that Thy-1+cells were concentrated in portal tracts but were also scattered in parenchyma. In FACS-prepared cells, 0.18–3.08% (median 0.65%, n = 14) of cells were Thy-1+. Immunophenotyping revealed that some Thy-1+cells coexpressed cytokeratins 18 and 19, others, fibrinogen and cytokeratin 19. RT-PCR demonstrated that Thy-1+cells expressed mRNA for Thy-1, cytokeratin 18, and cytokeratin 19, and Thy-1+CD34+cells expressed mRNA for α-fetoprotein, transferrin, and hepatocyte nuclear factor-4α. Thy-1+cells were identified in fetal liver. These cells expressed several lineage markers, including coexpression of biliary and hepatocellular proteins and mRNA. These data suggest that Thy-1 is a marker of liver stem cells in human fetal liver.
Rietveld texture analysis by neutron diffraction of highly absorbing materials
Authors: Volz H. M. , Vogel S. C. , Necker C. T. , Roberts J. A. , Lawson A. C. , Williams D. J. , Daemen L. L. , Lutterotti L. , Pehl J.
Published: June 2006

We discuss the impact of strong absorption for thermal neutrons on data analysis and compare absorption corrections in the GSAS and MAUD Rietveld codes for texture and structural parameter refinement. Diffraction data were collected on the neutron powder diffractometer HIPPO at LANSCE from dysprosium and erbium, which are moderate-to-strong absorbers for thermal neutrons with absorption cross sections of 159 barns for Er and 994 barns for Dy at λ=1.8 Å. Both elements have hexagonal-close-packed (hcp) crystal structures, and the samples were various thicknesses of rolled foils. The orientation distribution functions (ODF) were fit to the same neutron time-of-flight data sets using two very different full pattern Rietveld analysis procedures. Spherical harmonics functions were fit to the textured data using GSAS. These data were also analyzed by the modified direct method E-WIMV using MAUD. The resulting pole figures from the ODFs determined by both Rietveld analysis packages are qualitatively similar, and the textures were confirmed by X-ray diffraction. Additionally, data from orthorhombic dysprosium and erbium fluoride powders show that atomic positions are not sensitive to absorption. We address inconsistencies and methodologies in data analysis when strong absorption is present.
Applications of X-ray microdiffraction in the imaging industry
Authors: Blanton Thomas N.
Published: June 2006

Characterization of materials used in the digital imaging industry has been performed using micro X-ray diffraction (microXRD) techniques. Case studies are described that demonstrate the use of microXRD for identification of phases, texture, and microstructure morphology of components used in imaging applications.
Measurement and modeling of internal stresses at microscopic and mesoscopic levels using micro-Raman spectroscopy and X-ray diffraction
Authors: Benedikt B. , Lewis M. , Rangaswamy P.
Published: June 2006

In this study, we use X-ray diffraction (XRD) and micro-Raman spectroscopy (MRS) to measure internal strains in sensors embedded in polymer matrix composites. Two types of strain sensors embedded in either chopped graphite fiber∕epoxy matrix composite (MRS) or unidirectional graphite fiber∕polyimide matrix composite (XRD) were investigated. For XRD measurements, the sensors were in the form of spherical aluminum inclusions with diameters ranging from 1 to 20 μm. Due to large cross section area of an incident X-ray beam, only average stresses are reported using the XRD approach. Complementary to XRD experiments, MRS was pursued to measure internal strains in Kevlar-49 fibers embedded in chopped graphite fiber∕epoxy matrix composite. In recent years, MRS as an experimental tool for microstrain measurements has drawn considerable attention mostly due to its excellent spatial resolution. The resolution of MRS typically ranges between 1 and 10 μm, which means that strains can be measured in individual sensors. The principle of this method relies on a change of certain molecular vibration frequencies as a result of an applied stress. Several examples are presented and discussed to demonstrate the potential of combining micro and macrostrain measurements and modeling to capture the stress distribution in heterogeneous materials.
A new position sensitive area detector for high-speed and high-sensitivity X-ray diffraction analysis
Authors: Taguchi Takeyoshi
Published: June 2006

A state-of-art semiconductor technology-based position sensitive area detector, namely D/teX-25, has recently been developed for high-speed and high-sensitivity X-ray diffraction (XRD) analysis of materials. X-ray powder diffraction intensities obtained by a D/teX-25 detector were found to over 50 times higher than those by a conventional scintillation counter. A D/teX-25 detector mounted on a conventional 2 kW XRD system has been used to collect ultrafast XRD data with scanning speeds up to 160°2θ per minute. Ultrahigh-speed XRD is particularly useful for time-resolved dynamical and in-situ studies. A D/teX-25 detector was successfully used on a Rigaku XRD differential scanning calorimetry (DSC) system for simultaneous measurements of XRD and DSC data under controlled temperature and humidity conditions. This has made possible the study of complex and rapid phase transformations of pharmaceutical terfenadine. The D/teX-25 area detector has also been used for recording two-dimensional XRD patterns showing the particle-size effects on α-quartz powder intensities and to obtain digital X-ray topographic images of a complex dislocation network in a Si wafer.
Detection of visible and latent fingerprints by micro-X-ray fluorescence
Authors: Worley Christopher G. , Wiltshire Sara S. , Miller Thomasin C. , Havrilla George J. , Majidi Vahid
Published: June 2006

Numerous methods are available to forensic scientists for detecting fingerprints in which the prints are treated with various agents to enhance the visual contrast between the print and the surface. In the present work, the spatial elemental imaging capabilities of micro-X-ray fluorescence (MXRF) were used to visualize fingerprint patterns based on inorganic elements present in the prints. A major advantage of using MXRF is that the prints are left unaltered for other analyses, such as deoxyribonucleic acid extraction or for archiving. Most of the fingerprints which were examined were imaged from the potassium and chlorine present in the print residue. Among the various prints studied, lower count rates were also observed in the elemental maps of Ca, Al, Na, Mg, Si, P, S, and the X-ray source scatter. A sebaceous oily fingerprint left by one subject was successfully imaged by MXRF, but sebaceous prints left by a different person were undetectable, indicating that print elemental composition may be person and/or diet dependent. Prints containing substances that might be found in real-world cases were also visualized including sweat, lotion, saliva, and sunscreen.
Full spectrum calculations of EDXRF spectra
Authors: Elam W. T. , Shen Bob , Scruggs Bruce , Nicolosi Joseph
Published: June 2006

Rapid and accurate methods are becoming available to calculate all of the relevant physical effects that contribute to an energy-dispersive X-ray fluorescence (EDXRF) spectrum, rather than just the characteristic line intensities given by the traditional fundamental parameters method. To evaluate the utility of such methods, we have calculated the full spectra of several compounds covering a wide range of compositions. The calculated spectra are compared directly with measured spectra. They include scattering of the X-ray tube lines and continuum, the Compton profile, and the detector response. Our results indicate that it is now possible to compute the full spectrum from an EDXRF system with very good accuracy.
Quantitative energy-dispersive electron probe X-ray microanalysis of individual particles
Authors: Ro Chul-Un
Published: June 2006

An electron probe X-ray microanalysis (EPMA) technique using an energy-dispersive X-ray detector with an ultrathin window, designated low-Z particle EPM, has been developed. The low-Z particle EPMA allows the quantitative determination of concentrations of low-Z elements, such as C, N, and O, as well as higher-Z elements that can be analyzed by conventional energy-dispersive EPMA. The quantitative determination of low-Z elements (using full Monte Carlo simulations, from the electron impact to the X-ray detection) in individual environmental particles has improved the applicability of single-particle analysis, especially in atmospheric environmental aerosol research; many environmentally important atmospheric particles, e.g. sulfates, nitrates, ammonium, and carbonaceous particles, contain low-Z elements. The low-Z particle EPMA was applied to characterize loess soil particle samples of which the chemical compositions are well defined by the use of various bulk analytical methods. Chemical compositions of the loess samples obtained from the low-Z particle EPMA turn out to be close to those from bulk analyses. In addition, it is demonstrated that the technique can also be used to assess the heterogeneity of individual particles.
Parameter studies for an optimized XRF-determination of Pb in bone
Authors: Cernohlawek N. , Wobrauschek P. , Streli C. , Zoeger N.
Published: June 2006

One of the main threats to human health from heavy metals is associated with the exposure to lead (Pb). In vivo X-ray fluorescence analysis (XRF) of human bone is a widely used technique to determine the total Pb body burden. The intention of this work was to study the feasibility of in vivo L-shell XRF measurements of Pb in bone using X-ray tubes as excitation sources. Parameter studies using direct tube excitation with various anode materials (Mo and W) and filters as well as different secondary targets and low-Z polarizers were performed with regard to the lowest limits of detection (LLD) achievable for Pb in bone matrix. A breakthrough for the development of a portable spectrometer was achieved by using an air-cooled low-power (50 W) Pd anode X-ray tube, Mo secondary target, and a Peltier-cooled silicon drift detector. LLDs for Pb in bone were determined from measurements on a plaster-of-paris standard without overlying tissue equivalent material and found to be around 0.6 μg∕g.
X-ray microtomographic imaging and analysis for basic research
Authors: Dunsmuir J. H. , Bennett S. , Fareria L. , Mingino A. , Sansone M.
Published: June 2006

For research facilities with access to synchrotron X-ray sources, X-ray absorption microtomography (XMT) has evolved from an experimental imaging method to a specialized, if not yet routine, microscopy for imaging the three-dimensional (3D) distribution of linear attenuation coefficients and, in some cases, elemental concentration with micron spatial resolution. Recent advances in source and detector design have produced conventional X-ray source instruments with comparable spatial resolution but with lower throughput and without element specific imaging. Both classes of instrument produce 3D images for analysis. We discuss an integrated approach for the implementation of analytical XMT to support basic research into the structure-property relationships of a variety of materials. The essential components include instrumentation for collecting quantitative 3D images, a 3D image processing environment to address questions as to the quantity, composition, geometry, and relationships among the features in one or more images, and visualization to provide insight and communicate results. We give examples of image analysis of resolved and unresolved pore spaces of sandstones.
Average Years of Potential Life Lost in Those Who Have Died from Brain and CNS Tumors in the USA
Authors: Thuppal Shalini , Propp Jennifer M. , McCarthy Bridget J.
Published: June 2006

The aim of this study was to quantify the impact of all primary malignant and nonmalignant brain and central nervous system (CNS) tumors on mortality in the USA in terms of years of life lost, an indicator of premature mortality in the population. In this study, US mortality data for the year 2001 from the National Center for Health Statistics and life tables from the US Census Bureau were used. Person-years of potential life lost (PYPLL) and average years of potential life lost (AYPLL) were calculated for all deaths due to brain and CNS tumors as an underlying cause. 16,819 deaths due to brain and CNS tumors occurred in 2001, leading to a total loss of 357,483 person-years of life and an average loss of 21.3 years (AYPLL). Hispanic men and women had an AYPLL of 31.7 and 33.9 years, respectively, a figure substantially higher than other race and ethnicity categories. Malignant tumors led to an AYPLL of 25 years, which was significantly higher than the AYPLL of 19 years due to nonmalignant tumors. The relative impact of tumors arising in the various anatomical sites in the brain and CNS among adults and among children was not similar. The use of population survival indicators, such as PYPLL and AYPLL, will help better understanding of the effect of racial, ethnic, gender and age differences on the mortality due to malignant and nonmalignant brain and CNS tumors. Information on years of life lost, as well as mortality data, will be useful in focusing research priorities and resources in this field.
Why Does the Heart Beat?
Authors: Silverman Mark E. , Grove Daniel , Upshaw Charles B.
Published: June 2006

Why does the heart beat? This question—known as the myogenic versus neurogenic theory—dominated cardiac research in the 19th century. In 1839, Jan Evangelista Purkinje discovered gelatinous fibers in the ventricular subendocardium that he thought were muscular. Walter Gaskell, in 1886, demonstrated specialized muscle fibers joining the atria and ventricles that caused “block” when cut and found that the sinus venosus was the area of first excitation of the heart. By examining serial embryologic sections, Wilhelm His, Jr, showed that a connective tissue sheet became a bundle connecting the upper and lower cardiac chambers, the bundle of His. Sunao Tawara traced the atrioventricular (AV) bundle of His backward to find a compact node of fibers at the base of the atrial septum and forward where it connected with the bundles of cells discovered by Purkinje in 1839. Tawara concluded that this “AV connecting system” originated in the AV node, penetrated the septum as the His bundle, and then divided into left and right bundle branches that terminated in the Purkinje fibers. Martin Flack and Arthur Keith studied the conduction system of a mole and found a structure in the sinoauricular junction that histologically resembled the AV node. They felt that this was where “the dominating rhythm of the heart normally begins” and named it the sinoauricular node in 1907. The ECG of Einthoven soon brought a new understanding to the complex electrical system that makes the heart beat. In 2006 and 2007, we celebrate the 100th anniversaries of the publication of the exciting discovery of the AV and sinus nodes, truly landmarks in our understanding of cardiac structure and physiology.