bluuebunny/crossref_metadata_2025 huggingface dataset:
Stress levels of dental students at the Fiji School of Medicine
Authors: Morse Zac , Dravo Uraia
Published: May 2007

Introduction:  The Fiji School of Medicine is the primary health care educational institution in Fiji and possesses the only dental school in the Pacific. The oral health programme is a multi‐entry/exit programme. The aim of this study was to determine the perceived sources or stress and at risk groups within the undergraduate oral health care programmes.

Methods:  A modified version of the Dental Environment Stress questionnaire was used to assess levels of stress for 41 items.

Results:  A total of 115 undergraduate students participated (response rate = 84%). Of the respondents, 54% were male and 46% were female; 55% were Indo‐Fijians, 18% Indigenous‐Fijians, 8% Polynesians, 7% Micronesians, whilst Melanesians and others were each 6%. Moderate to severe stressful items were: full loaded day, followed by criticism from clinical supervisors in front of patients, amount of assigned work, fear of failing a course or year, examination and grades, financial resources, fear of employment after graduation and fear of facing parents after failure. Of the questionnaire items, 24% had significant differences across year groups. Overall, third years were most stressed followed by fourth years, fifth years, first years and second years. Indo‐Fijians were the most stressed, followed by Indigenous‐Fijians, Polynesians, others and Melanesians. Females were significantly more stressed than males for 27% of items. Private fee‐paying students were more stressed than sponsored students.

Conclusion:  Overall stress levels were slight to moderate and were higher in senior years, Indo‐Fijians, females and private fee‐paying students.
Seasonal and daily plasma melatonin rhythms and reproduction in Senegal sole kept under natural photoperiod and natural or controlled water temperature
Authors: Vera L. M. , De Oliveira C. , López‐Olmeda J. F. , Ramos J. , Mañanós E. , Madrid J. A. , Sánchez‐Vázquez F. J.
Published: May 2007

Abstract:  The melatonin daily rhythm provides the organism with photoperiod‐related information and represents a mechanism to transduce information concerning time of day. In addition, the duration and amplitude of the nocturnal elevation gives information about duration and thus the time of year. In this study, we investigate the existence of an annual rhythm of plasma melatonin in the Senegal sole. Differences in plasma melatonin levels between fish kept at a controlled temperature (17–20°C) and those exposed to the environmental temperature cycle (11.5–25°C) were also examined throughout the year. Spawning was registered in both groups to determine the time of year in which reproductive rhythms occurred. Our results pointed to the existence of an annual rhythm of plasma melatonin at mid‐darkness (MD), with the highest levels (203 ± 44 pg/mL) observed when water temperature reached 25°C. Water temperature influenced nocturnal, but not diurnal melatonin. Daily melatonin rhythms showed seasonal differences, with higher mean nocturnal levels during the summer solstice (138 ± 19 pg/mL) and autumn equinox (149 ± 49 pg/mL). When animals were kept at a constant temperature throughout the year, plasma melatonin levels differed from those observed in fish exposed to the environmental temperature cycle. Regarding the reproductive rhythms, spawning was observed at the end of spring in sole kept under natural temperature conditions, whereas no spawning at all was registered in sole reared at a constant temperature. In short, both photoperiod and temperature affected melatonin production in the Senegal sole, transducing seasonal information and controlling annual reproductive rhythms.
Matrix metalloproteinase‐9 activity and expression is reduced by melatonin during prevention of ethanol‐induced gastric ulcer in mice
Authors: Swarnakar Snehasikta , Mishra Amartya , Ganguly Krishnendu , Sharma Anamika Vivek
Published: May 2007

Abstract:  Matrix metalloproteinases (MMPs) play an important role in degradation of gastric extracellular matrix proteins. However, no reports are available on the relationship between the activity of MMPs and gastric ulceration induced by alcohol. Our objective was to investigate the effect of melatonin (N‐acetyl‐5‐methoxytryptamine) on the regulation of MMP‐9 and MMP‐2 activities during prevention of ethanol‐induced gastric ulcer. Biochemical and zymographic methods were used to analyze MMP‐9 and ‐2 activities in gastric tissues of Balb/c mice following induction of gastric ulcer by ethanol. Our studies reveal that melatonin arrested cell injury, protein carbonyl formation, and lipid peroxidation in mice during gastroprotection. Melatonin dose‐dependently reduced proMMP‐9 activity that was induced (∼ 25‐fold) during ethanol‐induced gastric ulceration. Severity of gastric ulcers were correlated proportionately with increased dose of ethanol and elevated activity of proMMP‐9 and ‐2. The reduced activities of MMP‐9 and ‐2 were associated with reduced expression of TNF‐α and increased expression of tissue inhibitors of metalloproteinases (TIMP‐1 and TIMP‐2). We conclude that melatonin's ability to prevent ethanol‐induced gastric ulceration in mice is related to a reduction in proMMP‐9 activity and expression.
Comparison of Residual Stresses in the Mechanical Roll Expansion of HX Tubes Into TEMA Grooves
Authors: Williams Dennis K.
Published: May 2007

The mechanical roll expansion of heat exchanger tubes into tubesheets containing TEMA grooves, which are thought to aid in the mechanical integrity of the tube-to-tubesheet (TTT) joint, has for many years provided an acceptable means of completing a TTT joint. Inherent with the intentional roll expansion of the tube is the creation of a tensile residual stress field within the tube that is greatest in the transition region between the expanded and unexpanded zones of the tube. An additional complicating factor in the tube-to-tubesheet joint design is the choice of utilizing a seal weld or a “full strength” weld at the tube end in conjunction with a level of roll expansion quantified by the degree of tube wall reduction. This paper presents the results of an initial study of the mechanical roll expansion of 1in. diameter tubes into a typical TEMA-R designed tubesheet, utilizing two grooves in the tubesheet hole. Two combinations of tube and tubesheet materials are studied that include duplex stainless steel tubes and tubesheet, while the second combination includes type 321 tubes roll expanded into a 2‐1∕4 Cr-1 Mo tubesheet, clad with 321 SS overlay. The residual stress fields are calculated by the finite element method and employ a simplified two-dimensional nonlinear axisymmetric model.
Improving the Reliability of the Tube-Hydroforming Process by the Taguchi Method
Authors: Li Bing , Nye T. J. , Metzger Don R.
Published: May 2007

The tube-hydroforming process has undergone extremely rapid development. To ensure a reliable hydroforming process at the design stage, applying robust design methodologies becomes crucial to the success of the resulting process. The reliability of the tube-hydroforming process based on the tube wall thickness thinning ratio is studied in this paper. In order to improve the reliability of the process, the Taguchi method, which is capable of evaluating the effects of process variables on both the mean and variance of process output, is used to determine the optimal forming parameters for minimizing the variation and average value of the thinning ratio. Finite element simulation is used to analyze the virtual experiments according to the experimental arrays. A cross-extrusion hydroformed tube is employed as an example to illustrate the effectiveness of this approach.
Failure of Locally Buckled Pipelines
Authors: Dama E. , Karamanos S. A. , Gresnigt A. M.
Published: May 2007

Mechanical damage in steel pipelines in the form of local buckles due to excessive bending deformation may severely threaten their structural integrity. The present paper describes experimental and numerical research conducted to assess the structural condition of buckled pipes, subjected to both bending and internal pressure. Fatigue failure under repeated loading is mainly investigated, whereas pipe burst due to internal pressure is also examined. Three full-scale buckled pipe specimens are tested under pressure and bending loads to determine their structural capacity. In addition, using nonlinear finite element tools, an extensive parametric study is conducted to determine the critical locations at the buckled area at which maximum strain variation occurs, as well as to investigate the influence of several geometrical and mechanical parameters. Using the maximum strain range from the finite element computations and a simple S-N approach, reasonable predictions are obtained for the number of cycles to failure observed in the tests. The results of the present study demonstrate that, under repeated loading, fatigue failure occurs in the buckled area at the location of maximum strain range. It is also found that the burst pressure may not be affected by the presence of buckles.
High-Temperature Heat Exchanger Tube-Sheet Assembly Investigation With Computational Fluid Dynamics
Authors: Porter Michael A. , Martens Dennis H. , Duffy Thomas , McGuffie Sean
Published: May 2007

Many modern sulfur recovery unit process waste heat recovery exchangers operate in high-temperature environments. These exchangers are associated with the thermal reactor system where the tube-sheet–tube-ferrule assemblies are exposed to gasses at temperatures approaching 3000°F. Because sulfur compounds are present in the process gas, the carbon steel tube sheet and tubes in the assembly will be deteriorated by sulfidation as the operating metal temperature rises above 600°F. Ferrule systems are used to protect the carbon steel from exposure to excessive temperatures. The temperature distribution in the steel tube-sheet–tube-ferrule system is affected by process gas flow and heat transfer through the assembly. Rather than depend on “assumed” heat transfer coefficients and fluid flow distribution, a computational fluid dynamics investigation was conducted to study the flow fields and heat transfer in the tube-sheet assembly. It was found that the configuration of the ferrule installation has a large influence on the temperature distribution in the steel materials and, therefore, the possible sulfidation of the carbon steel parts.
Note on Shear Load-Testing Feedwater Heater Tube
Joints
Authors: Yokell Stanley
Published: May 2007

This paper describes some results of shear load testing of welded and hybrid expanded tube–to–tube-sheet joints. The construction consisted of strength welding SA-688-TP 304N tubes to SA350LF-2 tube sheets clad with stainless-steel type 308∕309 weld wire followed by hybrid expanding the tubes into the full thickness of thick double-grooved tube sheets. The author theorizes that the mechanism that led to all failures reported to have occurred in the welds∕heat-affected zones instead of the anticipated tube yielding resulted from loss of interfacial pressure between the expanded tubes and surrounding ligaments. The author further speculates that elastic and plastic tube deformation during application of axial loads during shear load testing caused loss of interfacial pressure, which eliminated the holding capacity of the expanded-in length of tubes and that there was sufficient flattening of the tube metal deformed into the annular grooves to permit the applied loads to be carried to the welds.
Proposed Design Criterion for Vessel Lifting Lugs in Lieu of ASME B30.20
Authors: Williams Dennis K.
Published: May 2007

This paper describes a method for evaluating the structural adequacy of various lifting lugs utilized in the erection and up righting of large pressure vessels. In addition, the analysis techniques are described in detail and design guidelines for vessel lifting are tendered. The statutory and provincial regulations in both the United States and the province of Alberta, Canada are also reviewed and discussed with respect to the too often utilized phrase “factor of safety” (FOS). The implied implications derived from the chosen FOS are also outlined. A discussion is presented as to the applicability of the ASME safety standard B30.20 entitled, “Below the Hook Lifting Devices” (1999, ASME, New York) and as to the severe shortcomings of the safety standard in its attempt to delve into the design of lifting devices, especially when applied to lifting lugs on large and heavy-weight pressure vessels. Exemplar lugs on vessels are defined and the finite element analyses and closed form Hertzian contact problem solutions are presented and interpreted in accordance with the proposed design criteria. These results are compared against the very limited design information contained within ASME B30.20. Suggestions for the revision and applicability of the safety standard are presented and discussed in light of the examples and technical justification presented in the following paragraphs. In addition, the silence of this safety standard on the very large contact stresses that are well known to exist between a lifting pin and clevis type geometry is also discussed. Because of the limited number of repetitive loading cycles that vessel lifting lugs actually experience during the service life of a vessel, a recommendation is made to either clearly exclude vessel lifting lugs from the scope of ASME B30.20 or to specifically include a separate design and analysis section within this standard to properly address the mechanical and structural design issues applicable to pressure vessel lifting lugs.
Determining Effective Thickness of Cylinders in Pressure Equipment With Significant Thickness Variations for Fitness for Service Assessments
Authors: Rodery Clay D.
Published: May 2007

In many in-service issues involving pressure equipment, it is often the case that the thickness of a cylinder reveals significant variations in thickness around its cross section. This variation could represent loss of thickness due to corrosion or erosion, or could involve additions of thickness from repair activities. A common issue deals with determining the overall affect of such variations on the integrity of the vessel. This paper describes a spreadsheet tool employing common geometric properties such that these thickness variations may be simply reduced to an effective thickness of the cylinder cross section. This effective thickness may then be used for purposes of conducting fitness for service assessments or to assist in the planning of repairs. The use of this tool is illustrated with two case studies.
Design for Leakage in Flange Joints Under External Loads
Authors: Koves William J.
Published: May 2007

This paper uses an analytical model based on the Pressure Vessel Research Council (PVRC) ROTT test gasket constants to compute leakage in gasketed flange joints subjected to internal pressure and external bending moments. The model results are compared to test data, and design recommendations are made, consistent with the ASME∕PVRC tightness-based methodology.
Considerations in the Design and Analysis of an ASME Section VIII, Div. 2 Reactor Support Skirt
Authors: Williams Dennis K. , Seipp Trevor G.
Published: May 2007

This paper describes the considerations employed in the finite element analysis of a relatively “short” support skirt on a hydrocarbon reactor vessel. The analysis is accomplished in accordance with ASME B&PV Code, Section VIII, Division 2 alternate rules in conjunction with the guidelines outlined in WRC Bulletin 429. This provides a sound basis for the classification of the calculated stress intensities. The support skirt is capable of sustaining the deadweight load in addition to resisting the effects of thermal displacements, wind loadings, overturning moments from external piping loads on the attached hydrocarbon reactor vessel, and friction between the skirt base plate and concrete foundation. The displacement and thermal boundary conditions are well defined and discussed in detail. The effects of multiple scenarios for the displacement boundary conditions are examined. The skirt design also employs a hot-box arrangement whereby the primary mode of heat transfer is by radiation. A discussion of the two-part analysis is included and details the interaction between the heat transfer analysis and the subsequent structural analysis. The heat transfer finite element analysis is utilized to determine the temperatures throughout the bottom of the vessel shell and head, as well as the integrally attached support skirt. Of prime importance during the analysis is the axial thermal gradient present in the skirt from the base plate up to and slightly beyond the skirt-to-shell junction. While the geometry of the subject vessel and skirt is best described as axisymmetric, the imposed loadings are a mixture of axisymmetric and non-axisymmetric. This combination lends itself to the judicious selection and utilization of the harmonic finite element and properly chosen Fourier series representation of the applied loads. Comparison of the thermally induced axial stress gradient results from the FEA to those obtained by the closed form beam-on-elastic-foundation are also tendered and discussed. Finally, recommendations are included for the design and analysis of critical support skirts for large, heavy-wall vessels.
Effects of auditory feedback deprivation length on the vowel ∕ε∕ produced by pediatric cochlear-implant users
Authors: Bharadwaj Sneha V. , Graves Amanda G. , Bauer Delia D. , Assmann Peter F.
Published: May 2007

Effects of auditory deprivation on speech production by ten cochlear-implanted children were investigated by turning off the implant for durations ranging from 0.3 to 5.0s and measuring the formant frequencies (F1 and F2) of the vowel ∕ε∕. In five of the ten talkers, F1 and/or F2 shifted when auditory feedback was eliminated. Without feedback, F2 frequency lowered consistently, suggesting vowel centralization. Phonetic transcription indicated that some of these acoustic changes led to perceptible shifts in phonetic quality. The results provide evidence that brief periods of auditory deprivation can produce perceptible changes in vowels produced by some cochlear-implanted children.
Regional bone mineral density in male athletes: a comparison of soccer players, runners and controls
Authors: Fredericson Michael , Chew Kelvin , Ngo Jessica , Cleek Tammy , Kiratli Jenny , Cobb Kristin
Published: May 2007

Objectives:

To investigate the association of soccer playing and long-distance running with total and regional bone mineral density (BMD).

Design:

Cross-sectional study.

Setting:

Academic medical centre.

Participants:

Elite male soccer players (n = 15), elite male long-distance runners (n = 15) and sedentary male controls (n = 15) aged 20–30 years.

Main outcome measurements:

BMD (g/cm2) of the lumbar spine (L1–L4), right hip, right leg and total body were assessed by dual-energyx-ray absorptiometry, and a scan of the right calcaneus was performed with a peripheral instantaneousx-ray imaging bone densitometer.

Results:

After adjustment for age, weight and percentage body fat, soccer players had significantly higher whole body, spine, right hip, right leg and calcaneal BMD than controls (p = 0.008, p = 0.041, p<0.001, p = 0.019, p<0.001, respectively) and significantly higher right hip and spine BMD than runners (p = 0.012 and p = 0.009, respectively). Runners had higher calcaneal BMD than controls (p = 0.002). Forty percent of the runners had T-scores of the lumbar spine between −1 and −2.5. Controls were similar: 34% had T-scores below −1 (including 7% with T-scores lower than −2.5).

Conclusions:

Playing soccer is associated with higher BMD of the skeleton at all sites measured. Running is associated with higher BMD at directly loaded sites (the calcaneus) but not at relatively unloaded sites (the spine). Specific loading conditions, seen in ball sports or in running, play a pivotal role in skeletal adaptation. The importance of including an appropriate control group in clinical studies is underlined.
Quantifying the risk of sports injury: a systematic review of activity-specific rates for children under 16 years of age
Authors: Spinks Anneliese B , McClure Roderick J
Published: May 2007

Injuries caused by sports and other forms of physical activity in young children constitute a significant public health burden. It is important to quantify this risk to ensure that the benefits of sport participation are not outweighed by the potential harms. This review summarises the literature reporting exposure-based injury rates for various forms of physical activity in children aged 15 years and younger. Forty eight studies were found, of which 27 reported injury rates per hourly based exposure measured and 21 reported injury rates according to some other measure. Fourteen different sports and activities were covered, mostly team ball sports, with soccer being the most widely studied. Injury definition and the method of ascertaining and measuring injuries differed between studies, which created a large variation in reported injury rates that did not necessarily represent actual differences in injury risk between activities. The highest hourly based injury rates were reported for ice hockey, and the lowest were for soccer, although the range of injury rates for both of these activities was wide. Very few studies have investigated sports-related injuries in children younger than 8 years or in unorganised sports situations.
Effect of caffeine supplementation on haematological and biochemical variables in elite soccer players under physical stress conditions
Authors: Bassini-Cameron Adriana , Sweet Eric , Bottino Altamiro , Bittar Christina , Veiga Carlos , Cameron Luiz-Claudio
Published: May 2007

Objective:To evaluate the effect of caffeine on white cell distribution and muscle injury markers in professional soccer players during exercise.

Methods:22 male athletes completed a placebo controlled double blind test protocol to simulate a soccer match, followed by a Yo-Yo intermittent recovery test.

Results:Exercise caused an increase in packed cell volume that was enhanced by caffeine. Caffeine and exercise had a synergistic effect on the blood lymphocyte count, which increased by about 38% after exercise, and by an additional 35% when combined with caffeine. Caffeine promoted an exercise independent rise in circulating monocytes, and a synergistic action of exercise and caffeine was observed on segmented neutrophils. Caffeine promoted thrombocytosis. Plasma adenosine deaminase, aspartate aminotransferase, and lactate dehydrogenase concentrations were enhanced by exercise, and alanine transaminase concentration was enhanced in both groups, with a synergistic effect of caffeine.

Conclusions:The pronounced increase in the white cell count in the group receiving caffeine appeared to be caused by greater muscle stress and consequently more intense endothelial and muscle cell injury. The use of caffeine may augment the risk of muscle damage in athletes.
Risk for leukaemia and brain and breast cancer among Danish utility workers: a second follow-up: Table 1
Authors: Johansen Christoffer , Raaschou Nielsen Ole , Olsen Jrgen H , Schz Joachim
Published: May 2007

Objective:

To update a study of risks for leukaemia, brain cancer and breast cancer in a Danish nationwide, population-based cohort of utility employees.

Methods:

A multivariate statistical model including information on age, duration of employment, date of first employment and level of occupational exposure to electromagnetic fields was applied.

Results:

No increased risk for these cancers was seen among 28224 subjects with more than 3 months of employment in whom cancer had not been diagnosed before first employment.

Conclusion:

The results do not support the hypothesis of an association between occupational exposure to magnetic fields in the electric utility industry and risks for leukaemia, brain cancer and breast cancer.
CHARACTERIZATION OF TOTAL SUSPENDED PARTICULATE (TSP) IN A MOUNTAINOUS REGION IN NORTHERN JAPAN
Authors: SAITOH K. , SERA K. , HIRANO K.
Published: May 2007

Total suspended particulate (TSP) samples were collected at the west-facing slope (altitude 700 m) of Mt. Moriyoshi in northern Japan, from 24 – 27 June (non-snow-clad period) and 11 – 14 December (snow-clad period) in 1996, with a one-hour sampling interval. The elemental composition and particle shape of TSP samples were determined and/or observed by Particle Induced X-ray Emission (PIXE), a Scanning Electron Microscope (SEM) combined with Energy Dispersive X-ray (EDX) analysis. In the hourly TSP samples collected during the non-snow-clad period, 27 elements were determined. Na, Mg, Al, Si, S, K, Ca and Fe were found to be the major elemental components. On the other hand, 25 elements, excluding Nd and Mo, were found in the snow-clad period samples, and Cl is a dominant element, i.e., a major element, of the snow-clad period samples, unlike the non-snow-clad period. Comparing the arithmetic means of concentrations of major elements in TSP for non-snow-clad and snow-clad periods, Mg, Al, Si, K, Ca and Fe levels in the snow-clad period are 2 – 4 times as much as those in the non-snow-clad period, and 30 times for Na. S is similar. For temporal variation patterns of element concentrations, the non-snow-clad period is different from the snow-clad period. Al, S, Ca, Ti, Fe, Zn and Pb are similar throughout the non-snow-clad period, and Al, Si, Ca and Fe are similar throughout the snow-clad period. With the aid of SEM and EDX analysis, aggregates of car exhaust particles, soil particles and plant spores were observed in the non-snow-clad period samples. In the snow-clad period samples, small silicon-rich spherical particles, aggregates of car exhaust particles and soil particles were observed.
INVESTIGATION OF THE ELEMENTAL CONCENTRATION OF KIDNEY STONES BY PIXE ANALYSIS
Authors: Ashok M. , Narayana Kalkura S. , Vijayan V. , Magudapathy P. , Nair K. G. M.
Published: May 2007

Kidney stones collected from different hospitals in Chennai, south India were analyzed by PIXE with 3MeV protons. The matrix was calcium oxalate and mixture of calcium oxalate and calcium phosphate. Light elements present in minor concentration were P, Cl. Trace elements such as V, Cr, Mn, Fe, Cu, Zn, Sr, Zr & Mo were also present in the stones. Significant amount of Zr was found in one of the samples, Pb and Cd were not present in any of the stones analyzed.
INVESTIGATION ON THE INFLUENCE OF BACK SCATTERED PROTONS IN PIXE SPECTRUM
Authors: Satoh T. , Ishii K. , Matsuyama S. , Yamazaki H. , Amartivan Ts. , Tanaka A. , Sugihara S. , Komori Y. , Katoh K. , Kamiya T. , Sakai T. , Arakawa K.
Published: May 2007

The pre-amplifier with an active reset system was examined to carry out PIXE analysis under the condition that X-rays and back scattered protons are detected simultaneously. Rejection of false signals produced by back scattered protons is discussed, and it is confirmed that false signals can be completely rejected by using an inhibit signal of the preamplifier. Energy resolution of an X-ray detector and a live-time of measurement system were measured as a function of counting rate. As a result, energy resolution did not change and the live-time was 70 % at the high counting rate over 3kcps. The pile-up effect on the X-ray signal with the proton signal tail is also discussed.
PIXE STUDY OF AIRBORNE PARTICULATE MATTER IN NORTHERN MEXICO CITY
Authors: FLORES M. J. , ALDAPE F.
Published: May 2007

The contribution to the atmospheric pollution in Mexico City's conurbation that comes from the northern area has been considered significant for a long time. Therefore, it is important to determine its elemental composition as well as their correlation in sites along the suspected trajectories of airborne particulate matter. Samples were collected simultaneously in two sampling sites along the prevailing wind trajectory in northern Mexico City, and its elemental composition were determined by PIXE. The Sample collection was performed daily from 17 February 14 March 1997 in Xalostoc, an industrial zone in the State of Mexico, and Ticomán within Mexico City. Two samples a day were taken in two periods: 7-19 h and 19-7 h. The samplers used separated particles into two particle size fractions fractions, PM25 and PM15. Three main correlation group of elemental concentrations were determined: fuel combustion, earth crust and industrial origin. The sampling site within Mexico City, Ticomán, was found with an overall tendency of higher elemental concentrations, showing not only influence of local pollution sources, but also that of wind transported particles from neighboring industrial zones such as Xalostoc.
PIXE ANALYSIS OF URBAN ROADSIDE SOIL
Authors: Oguri Y. , Ebihara A. , Kambe N. , Dazai R. , Fukuda H. , Hasegawa J.
Published: May 2007

In order to study the influence of motor vehicles on a local soil environment, depth profiles of elemental concentration of urban roadside soil were investigated by means of thick-target PIXE analysis. For comparison, we analyzed the soil sampled in a university campus with very low traffic intensity. From the measured depth profiles, it was found that the roadside surface layers up to the depth of approximately 5 cm from the ground level are highly polluted by S and Zn. According to cluster analysis this pollution can be attributed to the deposition of tire dust due to the heavy vehicular traffic volumes on the highways.
APPLICATION OF MICROPIXE TO ELEMENTAL IMAGING OF THE RAT TESTIS
Authors: HOMMA-TAKEDA S. , NISHIMURA Y. , WATANABE Y. , IMASEKI H. , YUKAWA M.
Published: May 2007

The MicroPIXE technique was employed to reveal detailed distributions of trace elements in the testis, which distinguish the cell type-differences corresponding to the germ cell development (the 14 designated stages of the seminiferous epithelium cycle). Clear elemental imagings were obtained for P and S with a 50 μ m-thick section; S was higher in elongated spermatids in stages VII-VII, where a lower level of P was observed. Elemental imagings of Cu, Fe, Mn, Se, and Zn were obscure compared with P and S, but information about their localization in the seminiferous epithelium was obtained. These results suggest that microPIXE analysis is a powerful technique for investigation of elemental dynamics in the testis, although an improvement of detection for testicular trace elements is required.
Accumulation of copper and generation of hydroxyl radicals of hepatocellular carcinoma
Authors: Fukuda Hiroyuki , Ebara Masaaki , Arimoto Manaka , Obu Masamichi , Kin Shinnen , Yoshikawa Masaharu , Sugiura Nobuyuki , Saisho Hiromitsu , Yukawa Masae , Ikota Nobuo , Ozawa Toshihiko , Ogura Yasumitsu , Suzuki Kazuo
Published: May 2007

Aims: This study evaluated the connection between the progression of hepatic fibrosis and trace metals, the distribution profiles of copper(Cu) and Zinc (Zn) and the generation of hydroxyl radicals from Cu- metallothionein (MT) purified from human hepatocellular carcinoma (HCC).

Methods: We measured the metal contents in HCC tissue and liver parenchyma in patients with HCC. The content of metals in the liver was measured by particle induced X-ray emission (PIXE). Distribution profiles of Cu and Zn in human liver was evaluated by high-performance liquid chromatography (HPLC). The generation of hydroxyl radicals was measured by electron spin resonance (ESR) spin-trapping technique.

Results: Hepatic copper content increased with the progression of hepatic fibrosis. Copper level in liver parenchyma was higher in patients with HCC than in those without HCC (p < 0.01). MT was mainly present as Zn-MT in normal liver, Cu,Zn-MT in surrounding liver parenchyma and Cu-MT in HCC (p < 0.01). The signal intensity of the ESR spectrum in HCC was stronger than those in normal liver and surrounding liver parenchyma.

Conclusions: Copper accumulation in the liver parenchyma seems to relate to hepatocarcinogenesis.
ELEMENTAL DISTRIBUTION IN ORGANS OF MEDAKA, Oryzias laptipes, BURDENED WITH X-RAY IRRADIATION AND SALTY WATER (Part II)
Authors: YUKAWA MASAE , ISHIKAWA YUJI , IMASEKI HITOSHI , AOKI KAZUKO
Published: May 2007

Balance of essential elements in organisms might be changed by environmental stresses. Small teleost fish, Medaka, was burdened with X-ray irradiation (total dose: 17Gy) and salty water (70% NaCl of sea water). These stresses are not lethal dose. Essential elements in various organs in the fish were measured by PIXE method and compared with a control fish to determine the effect of two types of the burdens on the elemental contents. P, K, Ca and Br are examined in brain, eye, liver, ovary, spleen and intestine. P and K did not change their concentrations with both of the stresses. Ca concentrations increased under both stresses in the brain, eye, liver and spleen, and decreased in the intestine and ovary. Br concentrations of the organs largely changed in the case of salty water breeding. Micro-beam scanning PIXE provided elemental mapping of thin section of Medaka eye with STIM imaging.
APPLICATION OF MICRO-PIXE AND ICP-MS TO ANALYSIS OF ELEMENTAL DISTRIBUTION IN ROOT APEX OF PLANTS
Authors: WATANABE Y. , HOMMA-TAKEDA S. , YUKAWA M. , NISHIMURA Y. , IMASEKI H.
Published: May 2007

Micro-PIXE and inductively coupled plasma mass spectrometry (ICP-MS) were applied to elemental distribution analyses in plant root apex which is composed of various types of tissues and cells in different developmental stages. ICP-MS was so sensitive that a large number of elements including Na, Mg, P, S, K, Ca, Mn, Fe, Cu, Zn, Se, Rb, Sr and Cs could be determined quantitatively. These fourteen elements included almost all the essential elements for plant growth. Only a rough estimation, however, could be obtained by ICP-MS for the elemental distribution at the tissue level, by analyzing sections from the root apex. On the other hand, micro-PIXE was effective for detailed mappings of elemental distributions. The images of elemental distributions were obtained for Na, Mg, P, S, K, Ca, Mn, Fe and Zn, corresponding to the microscopic images of the root structures. The localizations of P, K and Zn in some tissues were observed by the mappings. These results indicated that micro-PIXE and ICP-MS have different, but complementary abilities for the investigation of elemental distributions in plant tissues.
APPLICATION OF A STANDARD-FREE METHOD TO QUANTITATIVE ANALYSIS OF URINE SAMPLES
Authors: SERA K. , MIURA Y. , FUTATSUGAWA S.
Published: May 2007

A standard-free method of quantitative analysis, which is based on the fact that the total yield of continuous x-rays from the sample approximately corresponds to effective weight of the sample, was developed and has been applied to some typical bio-samples such as serum, whole blood, hair and untreated bone. In this work, the standard-free method was applied to untreated urine samples. This method allows us to perform sample preparation only by dropping 5 μl of urine sample onto a backing film. It requires neither a large amount of urine nor the internal standard. As the results, values of concentration of potassium for 4 samples agree well with the value obtained by the internal standard method within an error of 10%. The present method was also applied to 21 urine samples containing excess amount of urinary protein and / or sugar, and it is found that the present method is applicable to such abnormal urines. Owing to this method, target preparation can be performed at the place and time of sampling. It is quite convenient to environmental studies.
MATRIX EFFECTS ON K-SHELL IONIZATION CROSS SECTIONS IN Al/Si ALLOYS
Authors: NEKAB M. , HEITZ Ch.
Published: May 2007

Thick targets consisting in Al/Si alloys were bombarded with 1.0 to 5.0 MeV Ar ions. The K X-ray production cross sections were deduced from the measured yields by using the Merzbacher-Lewis formula extended to heavy ion bombardment. The density dependence on the K X-ray production cross sections of Al and Si was observed. This phenomena can be interpreted within the molecular orbital double-scattering mechanism.
PIXE ANALYSIS OF HAIR IN ARSENIC POLLUTION, BANGLADESH
Authors: HABIB M. A. , MIONO S. , SERA K. , FUTATSUGAWA S.
Published: May 2007

The groundwater pollution by arsenic in Bangladesh causes a serious problem for millions of people who are exposed to poisoning by this toxic element. In an attempt to evaluate the extent of arsenic poisoning, hair samples of people living in Pabna district were collected. The hair samples were analyzed using Proton Induced X-ray Emission (PIXE) through exciting the atoms of a specimen so that their intensities can be converted into elemental concentrations in the specimen. The elements present in the specimen are identified by the corresponding X-ray energies and their concentrations are deduced from the X-ray intensities. The results from hair samples indicate substantially higher level of arsenic than those demarcated as toxic levels, in people from member families both affected and non-affected by poisoning. We correlate it with exceedingly high arsenic concentration in drinking water far above the permissible limit. The analytical results are compared with the results of arsenic and other elemental analysis of 160 Bangladeshi hair samples with that of 250 Japanese samples. The results show markedly higher levels of arsenic, manganese, iron and lead where the latter three elements show a positive relation with arsenic in the case of Bangladeshi as compared to the samples from Japan. On the other hand, selenium concentrations show very low level in the Bangladeshi samples compared to Japanese, displaying an inverse relationship with arsenic. The mechanism of arsenic in relation to other elements in the human body needs further investigation. The preliminary results call for detailed experimental and epidemiological studies to further characterize these aspects.
INFLUENCE OF ALUMINUM ON ELEMENTAL CONTENTS IN WHITE ROOTS OF CHAMAECYPARIS OBTUSA SIEB. AND QUERCUS SERRATA THUNB.
Authors: TOMIOKA RIE , TAKENAKA CHISATO , SAITOH KATSUMI , SERA KOICHIRO
Published: May 2007

We studied the effects of aluminum on macro- and microelement concentrations in white roots of Chamaecyparis obtuse and Quercus serrata Thunb. through analysis by Particle Induced X-ray Emission (PIXE). One-year-old seedlings were exposed to various concentrations of Al for nine weeks. In both species, the Al and P concentrations increased as the Al concentration in the nutrient solution increased, but the concentrations of the divalent cations Mg, Zn, and Mn decreased in both species.
PIXE ANALYSIS OF HUMAN BLOOD IN CANCER
Authors: HOTA P. K. , SENAPATI S. N. , GIRI S. K. , PARIJA U. R. , JENA RABINDRA KUMAR , VIJAYAN V.
Published: May 2007

Elements like potassium, calcium, iron, zinc, copper, selenium and lead were analyzed in human blood samples collected from different cancer patients as well as some healthy persons applying Particle Induced X-ray Emission (PIXE) technique at the Institute of Physics, Bhubaneswar. The results obtained were compared and discussed with the reported literature values. Some blood elements were found varying significantly in cancer patients compared to those of their healthy counterparts, which could suggest that fluctuations in trace element profiles in whole blood possibly can be used as a diagnostic tool as well as a prognostic index in cancer.
PRELIMINARY MEASUREMENTS OF THE LOW ENERGY DETECTION EFFICIENCY OF A Si(Li) DETECTOR FOR PIXE APPLICATIONS
Authors: RODRIGUEZ M. , YONEZAWA T. , ISHII K. , MATSUYAMA S. , YAMAZAKI H. , SATO T. , AMARTAIVAN TS. , SUGIHARA S. , TANAKA A. , KATO K. , KOMORI Y.
Published: May 2007

The low energy detection efficiency of a Si ( Li ) detector is measured in this work. The continuous bremsstrahlung spectrum produced by bombarding a thick C target with an electron beam is used as the standard radiation source. The bremsstrahlung spectrum for a thick C target is calculated from tabulated data assuming the thick target to consist of an array of thin layers applying the respective attenuation correction for photons emitted in each thin layer. The bremsstrahlung spectra for three incident electron energies (10, 12 and 15 keV) are measured and compared with the calculated ones. The relative efficiency is obtained and compared with a calculated efficiency based on the detector specifications. The efficiency measured for those three incident electron energies on the thick target are consistent with each other. The region limited by 2 keV < k < 6 keV , where k is the X-ray energy, exhibits a significant discrepancy between measurements and calculated efficiencies. A possible explanation of the observed discrepancy is that the real thickness of the Si dead layer is thinner than the one reported by the manufacturer. The obtained efficiency values are valid within the range 0.8 keV < k < 12.5 keV .
IN-AIR MICRO-PIXE ANALYSIS OF TISSUE SAMPLES
Authors: Tanaka A. , Ishii K. , Komori Y. , Matsuyama S. , Yamazaki H. , Oishi Y. , Rodriguez M. , Amartaivan Ts. , Kubota K. , Fukuda H. , Kamiya T. , Satoh T. , Sakai T. , Oikawa M. , Arakawa K. , Saidoh M.
Published: May 2007

Micro-PIXE is capable of providing spatial distributions of elements in the micro-meter scale and its application to biology is useful to elucidate the cellular metabolism. Since, in this method, a sample target is usually irradiated with proton or α-particle beams in vacuum, beam heating results in evaporation of volatile elements and shrinking of the sample. In order to avoid these side effects, we previously developed a technique of in-air micro-PIXE analysis for samples of cultured cells. In addition to these, analysis of exposed tissue samples from living subjects is highly desirable in biological and medical research. Here, we describe a technique of in-air micro-PIXE analysis of such tissue samples. The target samples of exposed tissue slices from a Donryu rat, in which a tumor had been transplanted, were analyzed with proton micro-beams of 2.6 MeV. We report that the shape of cells and the distribution of volatile elements in the tissue sample remain uncharged when using a target preparation based on a freeze-drying method.
STUDY OF THE APPLICATION OF PSS AT SYNCHROTRON RADIATION
Authors: HU ZHAOHUI , LIU PINGSHENG , HUANG YUYING , WANG BAOYI , FENG GUOHUA , BUDNAR MILOŠ , PELICON PRIMOŽ , KAVČIČ MATJAŽ
Published: May 2007

The paper presents the verification of home made Position Sensitive Spectrometer (PSS) while using synchrotron radiation light (SRL) as an excitation source. When Cr in the substance of light base was analyzed by the PSS, the lowest detection limit of a few ppm was achieved. Also linear proportionality between the count rate of the PSS and Cr concentration was obtained. This verities the feasibility of trace element analysis with high-energy resolution when using the PSS. At measurement of Cr Kβ5 band in metallic Cr and its compounds, it was discerned that the intensity of Cr Kβ5 becomes more intense with increasing oxidation number of Cr compounds. Such a change shows that high-energy resolution analysis using the PSS can make a useful method for the study of chemical states.
A METHOD FOR CRYOSECTIONING OF PLANT ROOTS FOR PROTON MICROPROBE ANALYSIS
Authors: SCHNEIDER THORSTEN , SCHELOSKE STEFAN , POVH BOGDAN , TRAXEL KURT
Published: May 2007

By building up a cryo-preparation laboratory a method was developed which allows us to prepare cryo sections of fully differentiated plant-root material, according to the requirements of the proton microprobe. Since cryo-preparation is the only possible method delivering reliable elemental distributions, this step was a fundamental for all our further investigations in plant root physiology. As an example, PIXE-investigations of a root section of a heavy metal hyper-accumulating plant Brassica juncea L. will be presented.
HEAVY METALS IN EDIBLE MUSHROOMS
Authors: KEMP KAARE
Published: May 2007

It has been reported that edible mushrooms are able to enrich the concentrations of several heavy metals. The Cd has especially drawn attention due to its high toxicity. By using PIXE analysis for the determination of the heavy metals it is possible to obtain a screening of the content of a wide number of elements. By analysing different species it is shown that one or a few elements may be characteristic for a single species. It is especially remarkable that several species of the family Agaricaceae are enriching Ag to a very high degree (up to 200 ppm).
TRACE ELEMENT ANALYSIS OF SOUTH INDIAN GALLSTONES BY PIXE
Authors: ASHOK M. , KALKUPA S. NARAYANA , KENNEDY V. J. , MARKWITZ A. , JAYANTHI V. , NAIR K. G. M. , VIJAYAN V.
Published: May 2007

Particle Induced X-ray Emission (PIXE) was used to analyse the elemental concentration of gallstones collected from different parts of south India. Cholesterol gallstones are predominant in north India, whereas pigment gallstones are predominant in south India. The black pigment gallstones are common in hemolytic anemia or in presence of infected bile. PIXE has revealed the elemental profile in each sample. The experimental subjects of the different groups displayed significant variation in their levels of certain trace elements such as copper, zinc, and iron. The concentration of copper was found to be predominant in pigment gallstones investigated in the present study.
SELENIUM CONCENTRATIONS IN RENAL CELL CARCINOMA
Authors: MIURA Y. , NAKAI K. , SUWABE A. , FUJIOKA T. , MATSUDA K. , SERA K.
Published: May 2007

In 30 healthy persons (control), 17 renal cell carcinoma (RCC) patients, 30 hemodialysis patients (HD) and 15 healthy persons in the Takko town (Aomori prefecture), the selenium concentration in serum was determined by PIXE. The mean serum selenium concentration in healthy controls was 1.4 ± 0.6 μ mol/l , in RCC patients 1.1 ± 0.4 μ mol/l , in HD patients 1.3 ± 0.9 μ mol/l and in healthy persons in the Takko town 1.7 ± 0.7 μ mol/l . There was a significant statistical difference between RCC patients and healthy persons in the Takko town ( p < 0.05). Takko town is famous for the production of garlic. Epidemiological studies have established an inverse relationship between garlic consumption and incidence of gastric, colon, and laryngeal cancers. Garlic is a rich source of selenium in the food. Contents of selenium in normal and carcinoma fractions in kidneys of RCC patients were determined by PIXE. The results indicate that RCC patients caused significant decrease of selenium contents in the carcinoma fraction ( p < 0.05).
ELEMENT DISTRIBUTION IN HEAVY METAL STRESSED CRYO-SECTIONS OF GEOSIPHON PYRIFORME
Authors: SCHELOSKE STEFAN , SCHNEIDER THORSTEN , SCHÜßLER ARTHUR
Published: May 2007

Geosiphon pyriforme is a unique symbiosis between a fungus, belonging to the arbuscular mycorrhizal (AM) fungi, and a cyanobacteria (blue-green algae). Since more than 80 % of the land plant species form an AM, the importance of this symbiosis becomes evident. In our research on heavy metal uptake and resistance of plants, Geosiphon is used as a model system for the AM symbiosis. Whilst we have studied heavy metal uptake of Geosiphon pyriforme from a macroscopic point of view we will now present first and preliminary results of element distributions in heavy metal stressed and non-stressed cryo-sections of Geoslphon pyriforme.