bluuebunny/crossref_metadata_2025 huggingface dataset:
LARGE MAGNETIC MOMENTS GENERATED FROM LOOP CURRENTS IN CARBON NANOTUBE ATTACHED TO ELECTRODES — A THEORETICAL PICTURE
Authors: TSUJI NAOTO , TAKAJO SHIGEHIRO , AOKI HIDEO
Published: May 2007

Inspired by a recent experiment which has detected a large orbital magnetic moment when electrodes are attached to a carbon nanotube, we study the ballistic transport in metallic carbon nanotubes when a current is injected from electrodes with finite bias voltages with nonequilibrium Green's function method. We reveal, both analytically and numerically, that large loop currents circulating around the tube are induced, which come from a quantum mechanical interference, when the injected electron is resonant with a time-reversed pair of degenerate states inherent in the zigzag and chiral nanotubes. This results in large orbital magnetic moments, making the nanotube a molecular solenoid. The current distribution for various types of tube and the magnetic moment as a function of the bias are displayed.
MAGNETIC CIRCULAR DICHROISM IN EUTE IN THE FERROMAGNETIC ORDER
Authors: HENRIQUES A. B. , MANFRINI M. A. , GALGANO G. D. , DIAZ B. L. , RAPPL P. H. O. , ABRAMOF E.
Published: May 2007

We investigated the polarized optical absorption near the band-edge of EuTe in high magnetic fields, for a ferromagnetic order of the S=7/2 spins in the Eu 2+ lattice sites. In samples grown by molecular beam epitaxy, the Faraday geometry absorption spectrum is described by a doublet of narrow lines, which is characterized by a huge splitting (about 300 meV) for left and right circularly polarized light. The nature of these absorption lines is analyzed in the framework of the narrow d-conduction band model, and a comparison between theoretical and experimental absorption spectra is presented. Such a comparison allows us to provide a quantitative description of the excited electronic states responsible for the observed optical absorption, when the lattice spin order is ferromagnetic.
AHARONOV-BOHM EFFECT IN THE QUANTUM HALL REGIME
Authors: GIESBERS A. J. M. , ZEITLER U. , MAAN J. C. , REUTER D. , WIECK A. D.
Published: May 2007

We have fabricated quantum rings in a GaAs/GaAlAs heterostructure 2DEG by local anodic oxidation with an atomic force microscope. In low magnetic fields we observe Aharonov-Bohm oscillations with a period of 60 mT corresponding to an effective ring diameter of 300 nm. In the high field regime, between filling factors ν = 2/3 and ν = 3, we observe Aharonov-Bohm oscillations of quantum Hall edge channels with a surprisingly large period, Δ B = 163 mT , corresponding to an edge channel around the inner diameter of the ring.
SPATIAL DISTRIBUTION OF KNIGHT SHIFT AROUND QUANTUM HALL EDGE CHANNELS USING RESISTIVELY-DETECTED NMR
Authors: MASUBUCHI S. , HAMAYA K. , MACHIDA T.
Published: May 2007

We develop a method for studying spatial distribution of the Knight shift using resistively-detected nuclear magnetic resonance (NMR) in an AlGaAs/GaAs quantum Hall device. By controlling the position of the dynamic nuclear polarization with the side-gate voltage, the spatial distribution of the NMR spectrum is investigated in a vicinity of quantum Hall edge channels. The value of Knight shift gradually changes in the region where the local Landau-level filling factor is between ν = 1 and ν = 2, implying that the change of the local electron spin polarization is detected in the edge channel.
SPATIAL MAPPING OF FLUCTUATIONS OF NONEQUILIBRIUM ELECTRONS IN QUANTUM HALL CONDUCTORS
Authors: KAWANO YUKIO , ISHIBASHI KOJI
Published: May 2007

We have investigated spatial properties of charge fluctuations in a quantum Hall (QH) conductor. This study has become possible by imaging electrical noise with a scanning electrometer based on a QH device. The experimental results have showed that the distribution maps of the noise strongly depend on a Landau-level-filling factor ν: At ν=2.38, the noise is concentrated in the channel edge region whereas at ν=1.75, the noise occurs over the almost entire channel region. From comparison with conventional resistance measurements, we interpret that the former and the latter can be attributed to an unstable relaxation of non-equilibrium edge-state electrons and a multiple-trapping of bulk-state electrons, respectively. Our noise-imaging technique thus provides a useful tool for investigating separately fluctuations of edge-state electrons and those of bulk-state electrons.
PHOTOLUMINESCENCE OF A HIGH MOBILITY 2DEG IN THE FRACTIONAL QUANTUM HALL EFFECT REGIME
Authors: SMIRNOV D. , RUDENKOV V. V. , ASHKINADZE B. M. , COHEN E. , CHRISTIANEN P. C. M. , MAAN J. C. , PFEIFFER L. N.
Published: May 2007

The magneto-PL spectra of modulation-doped, ultra-high mobility GaAs/AlGaAs single heterojunctions (HJs) were studied under a perpendicularly applied magnetic field up to 33 T and at temperatures of 0.3 and 1.2 K. The spectra show remarkable intensity redistribution between free (bulk) exciton and 2DEG-hole PL channels occurring at electron filling factors, ν = 2 and 1. At 0.3 K, significant 2DEG-hole PL spectral changes are observed near ν = 2/3 and 1/3. Several heterojunctions with 2DEG density in the range of n2D - (1 - 2.7) · 1011 cm -2 display similar features. These spectral peculiarities are attributed to the modification of the 2DEG energy spectrum caused by the e-e interaction, in particular, the recombination of valence hole with the composite (fractionally-charged) particles of the magnetized 2DEG.

In HJs with lower n2D < 1011 cm -2, the observed PL evolution at ν < 1 is mainly determined by an intensity redistribution between the σ+ and σ- circularly-polarized free exciton PL components. In this case, the exciton energy is lower than the energy of the 2DEG-hole system, so that the free excitons do not dissociate near the magnetized 2DEG and thus, the 2DEG-hole PL is barely observed.
RELAXATION PROCESS OF ELECTORON-HOLE PAIRS IN Yb-DOPED AlAs/GaAs SUPERLATTICE IN HIGH MAGNETIC FIELDS
Authors: TAKAMASU TADASHI , SATO KOICHI
Published: May 2007

The rare-earth doped AlAs/GaAs superlattices were grown by molecular beam epitaxy method. From the magneto-oscillation of the interband broad photoluminescence peak, electrons accumulated in the well were analyzed.
EDGE MAGNETOPLASMONS FOR A NEW TYPE OF QUANTUM-WELL MICROWAVE DETECTOR
Authors: MIKHAILOV S. A.
Published: May 2007

We theoretically study the wavelength and the propagation length of the edge magnetoplasmons (EMP's), running along the edge of a two-dimensional (2D) electron layer in a semiconductor quantum-well structure with and without metallic gates. We show that the metallic gate suppresses the propagation of the EMP's, but the quality factor of the wave (q′/q″, where q′ and q″ are the real and imaginary parts of the complex EMP wavevector) can be larger in the gated structures as compared to the structures without the gate. The results may be useful for analysis of operation of the recently discovered microwave detectors and spectrometers operating at liquid nitrogen temperatures (Kukushkin et al., Appl. Phys. Lett. 86, 044101 (2005)).
MICROWAVE-MODULATED PHOTOLUMINESCENCE OF A TWO-DIMENSIONAL ELECTRON GAS
Authors: ASHKINADZE B. M. , LINDER E. , COHEN E. , PFEIFFER L. N.
Published: May 2007

The primary effect of microwave (mw) irradiation on a two dimensional electron gas (2DEG) is heating due to mw absorption by the electrons. At low lattice temperatures, pronounced secondary effects are observed: mw-induced modification of the photoluminescence (PL) spectrum and mw-induced resistance oscillations (MIRO). We present an experimental study of mw-modulated PL (MPL) spectroscopy in modulation-doped GaAs/AlGaAs QW's At low magnetic field strengths (B < 0.5 T ), the analysis of the MPL spectra indicates that they arise of a redistribution of the photoexcited holes within the energy states of the top valence band. This is caused by absorbing low-energy acoustic phonons that are emitted by the mw-heated 2DEG. We propose that these nonequilibrium phonons also affect the 2DEG mobility leading to the MIRO's.

For B > 0.5 T and intense mw-irradiation, new optically detected resonances (ODRs) are observed at magnetic fields that depend on the 2DEG density and approximately correspond to integer electron filling factors. We argue that these resonances result from a slight 2DEG density increase under mw irradiation with a concurent, low-energy PL spectral shift due to a small bandgap narrowing.
SPIN-RESOLVED MAGNETO-OPTICAL STUDY OF CdSe SINGLE QUANTUM DOT
Authors: Chen Zhanghai , Bai L. H. , Huang S. H. , Xiong H. , Shen S. C. , Souma I. , Hyomi K. , Murayama A. , Oka Y.
Published: May 2007

We report on the magneto-optical study of spin polarized energetic fine structures for exciton complex in single CdSe quantum dot (QD) by using micro- photoluminescence (micro-PL) spectroscopy. The zero-field splitting of exciton luminescence peak arisen from the anisotropic exchange interaction of carriers in the QDs was observed. The g-factors for exciton and negatively-charged exciton, i.e. trion in a single QD were determined by fitting the magnetic field dependence of the corresponding PL peaks. By exciting the single QD with circularly polarized light of σ- and σ+ polarization, the spin-up and spin-down trions were selectively generated. The ratio, τ/τsf, of the exciton lifetime and the time constants for the spin-flipping process of trion in a single QD was estimated to be 0.13, which implies a long spin-lifetime in single CdSe QD.
PHOTOLUMINESCENCE OF IMPURITY-BOUND EXCITONS AND TRIONS IN MAGNETIC FIELDS
Authors: WÓJS ARKADIUSZ , BRYJA LESZEK , GŁADYSIEWICZ ANNA , MISIEWICZ JAN , POTEMSKI MAREK
Published: May 2007

Recombination spectrum of excitons and positive trions is studied by two-beam magneto-photoluminescence of a two-dimensional hole gas. For acceptor-bound trions a low-energy cyclotron replica is observed, corresponding to a hole shake-up process. The experiment is supplemented by realistic numerical calculations, allowing for identification of individual transitions and connecting the splitting of the shake-up line directly with the hole mass.
DYNAMICS OF SPATIALLY INDIRECT EXCITONS IN SEMICONDUCTOR HETEROSTRUCTURES IN MAGNETIC FIELDS
Authors: UCHIDA KAZUHITO , MIURA NOBORU , SHIRAKI YASUHIRO
Published: May 2007

Magnetophotoluminescence from spatially separated excitons in type-II semiconductor heterostructures, GaP/AlP neighboring confinement structures (NCSs) have been investigated. The sample studied consists of adjacent GaP and AlP quantum wells sandwiched between AlGaP barriers. The excitation power dependence and the well thickness dependence of the exciton PL are studied in magnetic fields applied perpendicular to the heterointerfaces. Compared to the thinner NCS, the magneto-PL of the wider NCS is strongly modified by the excitation power; the magnetic field dependence of the PL peak energy clearly changes from the anomalous red-shifts into the diamagnetic shifts with increasing excitation laser power.
CYCLOTRON RESONANCE IN COUPLED BILAYERS IN HIGH MAGNETIC FIELDS
Authors: GÜRTLER A. , ZEITLER U. , MAAN J. C. , REUTER D. , WIECK A. D.
Published: May 2007

We present far-infrared cyclotron resonance measurements on a strongly coupled symmetric GaAs/GaAlAs double quantum well sample. Cyclotron resonance is measured at several discrete wavelengths and tilt angles of the sample with respect to the magnetic field. The width and strength of the resonance peaks depend strongly on the tilt angle and the laser wavelength, demonstrating the complexity of this system.
SEQUENTIAL RESONANT TUNNELING BETWEEN LANDAU LEVELS IN GaAs\AlGaAs SUPERLATTICES IN STRONG TILTED MAGNETIC AND ELECTRIC FIELDS
Authors: TELENKOV M. P. , MITYAGIN YU. A.
Published: May 2007

The transverse resonant tunneling transport and electric field domain formation in GaAs/AlGaAs superlattices were investigated in a strong tilted magnetic field. The magnetic field component parallel to structure layers causes intensive tunneling transition between Landau levels with Δn≠0, resulting in the considerable "inhomogeneous" broadening of intersubband tunneling resonance as well as in the shift of the resonance toward higher electric fields. This leads to noticeable changes of the I-V characteristics of the superlattice, namely to smoothing of the periodic NDC structure on plateau-like regions caused by formation of the electric field domains and to the shift of the plateaus toward the higher applied voltage. The predicted behavior of the I-V characteristics of the structures in magnetic field was found experimentally.
AN EMPIRICAL ANALYSIS OF THE OPEN SOURCE DEVELOPMENT PROCESS BASED ON MINING OF SOURCE CODE REPOSITORIES
Authors: SCOTTO MARCO , SILLITTI ALBERTO , SUCCI GIANCARLO
Published: May 2007

This paper presents an empirical analysis of the Open Source development process from the point of view of the involvement of the developers in the production process. The study focuses on how developers contribute to projects in terms of involvement, size and kind of their contribution. Data have been collected from 53 Open Source projects and target application domains include different areas: web and application servers, databases, operating systems, and window managers. Collected data include the number of developers, patterns of code modifications, and evolution over the time of size and complexity.

The results of this study show evidence that there are recurrent patterns in Open Source software development and these patterns are common to all the projects considered even if there are no superimposed processes for development, application domains are different, and there are contributions from people spread across the world.
ABSTRACT LOGIC TREE BASED FRAMEWORK FOR COMPONENT BASED SOLUTION COMPOSITION DESIGN AND EXECUTION
Authors: SUN WEI , ZHANG XIN , LIU YING , TIAN ZHONG
Published: May 2007

Component based development is gaining increasing popularity for agile system development through reuse of existing asset. To make this approach effective enough to implement, the paradigm of "solution = components + composition logic" should be successfully realized. The current component composition approaches are either not flexible enough, have less visibility of the composition logic or demanding heavy platform and technology dependencies. Abstract Logic Tree is a mechanism of using a task decomposition approach based on a divide-and-conquer strategy to support composition design and execution. In this paper, the design of the Abstract Logic Tree and related methodology, the composition logic modeling capability, and the supporting framework named DynaTree are presented. The travel plan case is used to demonstrate the solution development process through the Abstract Logic Tree method.
Maternal undernutrition inhibits angiogenesis in the offspring: a potential mechanism of programmed hypertension
Authors: Khorram Omid , Khorram Naseem , Momeni Mazdak , Han Guang , Halem Jennifer , Desai Mina , Ross Michael G.
Published: May 2007

The underlying etiology of many chronic diseases such as hypertension and diabetes has been traced to the in utero environment. Our interest has focused on determining the mechanism of programmed hypertension. In our rodent model of 50% maternal food restriction (MFR) from day 10 of gestation to term, the offspring develop hypertension as adults. We hypothesized that maternal undernutrition inhibits angiogenesis such that the neonate is endowed with fewer microvessels, increasing their susceptibility to develop hypertension as adults. We found significantly reduced number of mesenteric branching and renal medullary microvessels in the 1-day-old MFR newborns. Endothelial cells from MFR offspring generated shorter neovessels in culture compared with controls. The inhibition of angiogenesis was associated with a significant decrease in VEGF protein expression in mesenteric microvessels and aortas in 1-day-old offspring. However, in adulthood there was a marked increase in VEGF expression in both vessel types. The expression of endothelial nitric oxide synthase protein was also found to be increased in both renal and mesenteric microvessels and in aortas in the 1-day-old MFR offspring. These results suggest that MFR results in inhibition of VEGF expression in microvascular and aortic endothelial cells early in life, resulting in decreased angiogenesis and increased peripheral vascular resistance, both of which may contribute to offspring hypertension.
Effect of a 12-Month Randomized Clinical Trial of Exercise on Serum Prolactin Concentrations in Postmenopausal Women
Authors: Tworoger Shelley S. , Sorensen Bess , Chubak Jessica , Irwin Melinda , Stanczyk Frank Z. , Ulrich Cornelia M. , Potter John , McTiernan Anne
Published: May 2007

Prolactin is associated with an increased risk of postmenopausal breast cancer; however, few modifiable factors are known to reduce prolactin concentrations. Therefore, we examined the effect of a 12-month moderate-intensity exercise intervention on serum prolactin concentrations as a secondary end point (primary end points were estrogens and androgens). We randomly assigned 173 postmenopausal women who were sedentary, overweight (body mass index >24 kg/m2, body fat >33%), ages 50 to 75 years, and not using hormone therapy to an exercise intervention or stretching control group. The intervention was facility- and home-based (45 min, 5 days/wk moderate-intensity sports/recreational exercise). One hundred and seventy (98%) women completed the study. Prolactin concentrations were similar at baseline (P = 0.25, geometric mean exercisers = 6.9 and controls = 7.5 ng/mL). Overall, the intervention was not associated with changes in prolactin concentrations between exercisers and controls at 3 months (P = 0.46) or 12 months (P = 0.29). The intervention effect did not vary by baseline age, body mass index, parity, or change in percent body fat during the intervention. Among exercisers, there was a significant difference in prolactin concentrations by change in fitness (VO2max) between baseline and 12 months. Exercisers whose VO2max changed by <5% had a 5% increase in prolactin concentrations, whereas those who increased their VO2max by 5% to 15% and >15% had a 11% (P = 0.03) and 7% (P = 0.01) decrease in prolactin concentrations, respectively. Although the exercise intervention had little effect on prolactin concentrations overall, increasing physical fitness was associated with reduced prolactin concentrations among postmenopausal women. (Cancer Epidemiol Biomarkers Prev 2007;16(5):895–9)
Recreational Physical Activity and Mammographic Breast Density Characteristics
Authors: Reeves Katherine W. , Gierach Gretchen L. , Modugno Francesmary
Published: May 2007

Increased mammographic breast density is considered an intermediate marker of breast cancer risk. Physical activity is believed to reduce breast cancer risk; however, its effect on breast density is not well understood. We studied the association between recreational physical activity and mammographic characteristics of the breast among a population of premenopausal and postmenopausal women enrolled as controls (n = 728) in a case-control study of mammographic breast density and breast cancer. Women were enrolled shortly after obtaining their regular screening mammograms, and participants reported their current and lifetime recreational physical activity history using a self-administered, reliable questionnaire at study enrollment. Linear regression was used to determine associations between physical activity variables and the dense breast area, non-dense area, total breast area, and percent density. Age-adjusted analyses revealed significant inverse associations between physical activity variables and the non-dense area and total area and positive associations with percent breast density. These associations were attenuated and nonsignificant after adjustment for body mass index (BMI). Adjustment for additional factors did not substantially change the results. Physical activity was not associated with the dense breast area before or after adjustment for BMI. Self-reported recreational physical activity was not significantly associated with the mammographic characteristics of the breast after adjustment for BMI in this population. These results suggest that the mechanism by which physical activity reduces breast cancer risk may not involve breast density. (Cancer Epidemiol Biomarkers Prev 2007;16(5):934–42)
Usual Physical Activity and Endogenous Sex Hormones in Postmenopausal Women: The European Prospective Investigation into Cancer–Norfolk Population Study
Authors: Chan Mei-Fen , Dowsett Mitch , Folkerd Elizabeth , Bingham Sheila , Wareham Nicholas , Luben Robert , Welch Ailsa , Khaw Kay-Tee
Published: May 2007

Background: Short-term trials indicate that intensive physical activity may influence endogenous sex hormone concentrations. However, the relationship between usual daily physical activity and endogenous hormones in postmenopausal women in the general population is still uncertain.

Objective and Methods: To determine the relationship between usual physical activity and endogenous sex hormones in postmenopausal women. A cross-sectional population-based study of 2,082 postmenopausal women ages 55 to 81 years, residing in the general community of Norfolk, United Kingdom, and not currently using hormone replacement therapy were chosen to participate. Physical activity in the past 1 year was assessed using a validated questionnaire, and endogenous sex hormone and sex hormone–binding globulin (SHBG) concentrations were determined.

Results: Usual physical activity levels were inversely associated with circulating concentrations of testosterone and estradiol, testosterone/SHBG ratio, and positively associated with SHBG. These associations were only slightly attenuated after adjusting for potential covariates including body mass index, smoking status, alcohol intake, and reproductive variables. Testosterone concentrations and testosterone/SHBG ratios were 19% [95% confidence interval (95% CI), 9-27%, P < 0.001] and 24.0% (95% CI, 13-34% P < 0.001) lower, respectively, whereas estradiol concentrations were 6% (95% CI, 0-12%; P < 0.05) lower in the highest compared with lowest activity levels, respectively. A decreasing trend for the estradiol/SHBG ratio and 17α-hydroxyprogesterone concentrations was also observed. Androstenedione levels did not differ significantly according to physical activity.

Conclusions: Higher usual physical activity levels among postmenopausal women seem to be related to lower endogenous testosterone and estradiol concentrations. This may be one mechanism that could partly explain the reported inverse relationship between physical activity and breast cancer risk in some studies. (Cancer Epidemiol Biomarkers Prev 2007;16(5):900–905)
Evaluation of Genetic Variations in the Androgen and Estrogen Metabolic Pathways as Risk Factors for Sporadic and Familial Prostate Cancer
Authors: Cunningham Julie M. , Hebbring Scott J. , McDonnell Shannon K. , Cicek Mine S. , Christensen G. Bryce , Wang Liang , Jacobsen Steven J. , Cerhan James R. , Blute Michael L. , Schaid Daniel J. , Thibodeau Stephen N.
Published: May 2007

Previous studies suggest that enzymes involved in the androgen metabolic pathway are susceptibility factors for prostate cancer. Estrogen metabolites functioning as genotoxins have also been proposed as risk factors. In this study, we systematically tested the hypothesis that common genetic variations for those enzymes involved in the androgen and estrogen metabolic pathways increase risk for sporadic and familial prostate cancer. From these two pathways, 46 polymorphisms (34 single nucleotide polymorphisms, 10 short tandem repeat polymorphisms, and 2 null alleles) in 25 genes were tested for possible associations. Those genes tested included PRL, LHB, CYP11A1, HSD3B1, HSD3B2, HSD17B2, CYP17, SRD5A2, AKR1C3, UGT2B15, AR, SHBG, and KLK3 from the androgen pathway and CYP19, HSD17B1, CYP1A1, CYP1A2, CYP1B1, COMT, GSTP1, GSTT1, GSTM1, NQO1, ESR1, and ESR2 from the estrogen pathway. A case-control study design was used with two sets of cases: familial cases with a strong prostate cancer family history (n = 438 from 178 families) and sporadic cases with a negative prostate cancer family history (n = 499). The controls (n = 493) were derived from a population-based collection. Our results provide suggestive findings for an association with either familial or sporadic prostate cancer with polymorphisms in four genes: AKR1C3, HSD17B1, NQO1, and GSTT1. Additional suggestive findings for an association with clinical variables (disease stage, grade, and/or node status) were observed for single nucleotide polymorphisms in eight genes: HSD3B2, SRD5A2, SHBG, ESR1, CYP1A1, CYP1B1, GSTT1, and NQO1. However, none of the findings were statistically significant after appropriate corrections for multiple comparisons. Given that the point estimates for the odds ratio for each of these polymorphisms are <2.0, much larger sample sizes will be required for confirmation. (Cancer Epidemiol Biomarkers Prev 2007;16(5):969–78)
Concordance of Pharmacogenetic Polymorphisms in Tumor and Germ Line DNA in Adult Patients with Acute Myeloid Leukemia
Authors: Weiss Joli R. , Baer Maria R. , Ambrosone Christine B. , Blanco Javier G. , Hutson Alan , Ford Laurie A. , Moysich Kirsten B.
Published: May 2007

Archived tumor tissue is a useful resource for retrospective studies addressing relationships between genetic polymorphisms and treatment outcomes. However, genotypes determined in tumor and somatic tissues may differ due to cytogenetic and molecular changes associated with malignant transformation and progression. Discordance between germ line and tumor genotypes may be particularly relevant in leukemia because cytogenetic abnormalities are frequent. We compared genotypes determined in DNA extracted from paired pretreatment bone marrow and buccal samples from 80 adult patients with acute myeloid leukemia (AML). Paired AML and buccal DNA samples were genotyped for polymorphisms (21 single nucleotide polymorphisms and 2 gene deletions) on genes encoding proteins involved in drug metabolism (CYP3A4, CYP2C8, CDA, and GSTP1), oxidative stress mechanisms (CAT, MnSOD, GSTT1, GSTM1, GSTA1, and GPX1), drug transport (MDR1, MRP1, and BCRP), and DNA repair (MGMT, XPD, and XRCC1). Genotypes were determined by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, except GSTM1 and GSTT1, for which deletion genotypes were determined using multiplex PCR. Concordance of genotypes was tested by κ statistics. κ statistics for paired AML and buccal DNA samples ranged between 0.94 and 1.00, indicating excellent agreement. The GSTT1 and GSTM1 genotypes were in perfect concordance for the paired samples. Agreement was also excellent for genes at AML chromosome deletion and translocation breakpoints, including MDR1 at 7q21.1 and MRP1 at 16p13.1. Based on these data, genotypes derived from archived AML bone marrow samples were not likely to differ from those from genomic DNA, and archived bone marrow samples may be useful for the conduct of retrospective pharmacogenetic studies. (Cancer Epidemiol Biomarkers Prev 2007;16(5):1038–41)
Lactase Persistence, Dietary Intake of Milk, and the Risk for Prostate Cancer in Sweden and Finland
Authors: Torniainen Suvi , Hedelin Maria , Autio Ville , Rasinperä Heli , Bälter Katarina Augustsson , Klint Åsa , Bellocco Rino , Wiklund Fredrik , Stattin Pär , Ikonen Tarja , Tammela Teuvo L.J. , Schleutker Johanna , Grönberg Henrik , Järvelä Irma
Published: May 2007

Prostate carcinoma is the most common cancer in men. Its primary pathogenesis is mostly unknown. Dairy products containing lactose have been suggested to be risk factors for prostate cancer. Digestion of lactose is dependent on lactase activity in the intestinal wall. A single nucleotide polymorphism C to T residing 13,910 bp upstream of the lactase gene has been shown to associate with the developmental down-regulation of lactase activity underlying persistence/nonpersistence trait. To find out whether lactase persistence is related to the risk for prostate cancer, we genotyped 1,229 Finnish and 2,924 Swedish patients and their 473 Finnish and 1,842 Swedish controls using solid-phase minisequencing. To explore if dairy products have an association with prostate cancer, we analyzed the milk consumption in the Swedish study consisting of 1,499 prostate cancer patients and 1,130 controls (Cancer Prostate in Sweden I study) using a questionnaire. Only the consumption of low-fat milk was found to be associated with increased risk of prostate cancer [odds ratio (OR), 1.73; 95% confidence interval (95% CI), 1.16-2.39]. A statistically significantly higher (P < 0.01) lactose intake was observed among subjects with high lactase activity (C/T and T/T genotypes) compared with those with low lactase activity (C/C genotype). Lactase persistence did not associate with increased risk for prostate carcinoma in the Finnish (OR, 1.11; 95% CI, 0.83-1.47; P = 0.488) or in the Swedish populations (OR, 1.16; 95% CI, 0.91-1.46; P = 0.23). In conclusion, lactase persistence/nonpersistence contains no risk for prostate cancer. Analysis of different milk products showed some evidence for low-fat milk as a potential risk factor for prostate cancer. (Cancer Epidemiol Biomarkers Prev 2007;16(5):956–61)
Polymorphisms in the CYP19A1 (Aromatase) Gene and Endometrial Cancer Risk in Chinese Women
Authors: Tao Meng Hua , Cai Qiuyin , Zhang Zuo-Feng , Xu Wang-Hong , Kataoka Nobuhiko , Wen Wanqing , Xiang Yong-Bing , Zheng Wei , Shu Xiao Ou
Published: May 2007

Aromatase, encoded by the CYP19A1 gene, is a key enzyme in estradiol biosynthesis, which catalyzes the conversion of androstenedione and testosterone to estrone and estradiol, respectively. Given the critical role of estrogen in the development of endometrial cancer risk, we evaluated genetic polymorphisms of the CYP19A1 gene, including rs1065779, rs700519, rs28566535, rs752760, and rs1870050, in association with endometrial cancer in a population-based case-control study conducted in Shanghai, China. Genotypes of 1,040 incident endometrial cancer cases and 1,031 frequency-matched controls were included in the study. We applied a logistic regression model to derive adjusted odds ratios (OR) and their 95% confidence intervals (95% CI). Six common haplotypes with a frequency ≥5% were estimated; the highest frequency haplotype was GCACA (27.8% in cases and 26.2% in controls). We observed an inverse association between CYP19A1 haplotype TCATC and endometrial cancer in our population (OR, 0.76; 95% CI, 0.62-0.92). An inverse association was found between endometrial cancer and single nucleotide polymorphism rs1870050 in the promoter region with ORs of 0.81 (95% CI, 0.68-0.97) and 0.58 (95% CI, 0.42-0.80) for the AC and CC genotypes, respectively. We observed a multiplicative interaction between single nucleotide polymorphism rs700519 and body mass index among postmenopausal women (P = 0.01), with stronger associations between rs700519 genotypes and endometrial cancer risk among heavier (body mass index, ≥25) postmenopausal women. In summary, our data show that polymorphisms in the CYP19A1 gene may contribute to endometrial carcinogenesis. (Cancer Epidemiol Biomarkers Prev 2007;16(5):943–9)
Number of Nevi and Early-Life Ambient UV Exposure Are Associated with BRAF-Mutant Melanoma
Authors: Thomas Nancy E. , Edmiston Sharon N. , Alexander Audrey , Millikan Robert C. , Groben Pamela A. , Hao Honglin , Tolbert Dawn , Berwick Marianne , Busam Klaus , Begg Colin B. , Mattingly Dianne , Ollila David W. , Tse Chiu Kit , Hummer Amanda , Lee-Taylor Julia , Conway Kathleen
Published: May 2007

Malignant melanomas often contain BRAF or NRAS mutations, but the relationship of these mutations to ambient UV exposure in combination with phenotypic characteristics is unknown. In a population-based case series from North Carolina, 214 first primary invasive melanoma patients in the year 2000 were interviewed regarding their risk factors. Ambient solar UV exposures were estimated using residential histories and a satellite-based model. Cases were grouped on the basis of BRAF and NRAS somatic mutations, determined using single-strand conformation polymorphism analysis and radiolabeled DNA sequencing, and the risk profiles of these groups were compared. Mutually exclusive BRAF-mutant and NRAS-mutant cases occurred at frequencies of 43.0% and 13.6% with mean ages at diagnosis of 47.3 and 62.1 years, respectively. Tumors from patients with >14 back nevi were more likely to harbor either a BRAF mutation [age-adjusted odds ratio (OR), 3.2; 95% confidence interval (95% CI), 1.4-7.0] or an NRAS mutation (age-adjusted OR, 1.7; 95% CI, 0.6-4.8) compared with patients with 0 to 4 back nevi. However, BRAF-mutant and NRAS-mutant tumors were distinctive in that BRAF-mutant tumors were characteristic of patients with high early-life ambient UV exposure (adjusted OR, 2.6; 95% CI, 1.2-5.3). When ambient UV irradiance was analyzed by decadal age, high exposure at ages 0 to 20 years was associated with BRAF-mutant cases, whereas high exposure at ages 50 and 60 years was characteristic of NRAS-mutant cases. Our results suggest that although nevus propensity is important for the occurrence of both BRAF and NRAS-mutant melanomas, ambient UV irradiance influences risk differently based on the age of exposure. The association of BRAF mutations with early-life UV exposure provides evidence in support of childhood sun protection for melanoma prevention. (Cancer Epidemiol Biomarkers Prev 2007;16(5):991–7)
Serum Levels of Insulin-like Growth Factor-I and Insulin-like Growth Factor-I Binding Protein-3: Quality Control for Studies of Stored Serum
Authors: Berrigan David , Potischman Nancy , Dodd Kevin W. , Nicar Michael , McQuillan Geraldine , Lavigne Jackie A. , Barrett J. Carl , Ballard-Barbash Rachel
Published: May 2007

The insulin-like growth factor (IGF) axis, particularly IGF-I and IGF binding protein-3 (IGFBP-3), has been the subject of much attention because of its role in juvenile growth and their association with cancers at several sites. However, epidemiologic studies of IGF-I and IGFBP-3 have had mixed results and several authors have speculated that quality control (QC), sample storage history, and other methodologic concerns could play a role in this heterogeneity. This article documents the results of storage history and QC efforts for a study of IGF-I and IGFBP-3 in 6,226 serum samples from the National Health and Nutrition Examination Survey III (NHANES III). The study was carried out on site at Diagnostic Systems Laboratories in Webster, Texas, using the IGF-I ELISA (DSL 10-5600) and the IGFBP-3 immunoradiometric assay (DSL 6600). A run-in study of assay performance suggested that plates, days, and weeks significantly affected the variance of both assays. Analysis of samples with different storage histories also indicated strong effects of storage history. Serum samples disbursed to laboratories for measurement of diverse analytes and then returned for storage showed reductions in serum IGF-I level averaging 43% and reductions in IGFBP-3 of 25% compared with samples shipped immediately to the repository for long-term storage at −80°C. Therefore, the main study was carried out using samples that had been shipped directly to the National Center for Health Statistics/NHANES collection center for storage. Laboratory analyses of NHANES III and QC samples were carried out over ∼10 months. QC was monitored through repeated testing of blood samples from six individuals, with two individuals tested twice on each plate. Assay performance was stable over the entire study and coefficients of variation averaged 2% to 3% within plates and ∼14% for IGF-I and ∼11.5% for IGFBP-3 over the entire study. Coefficients of variation varied significantly among individual QC subjects, ranging from 12.3% to 17.6% for IGF-I and 8.9% to 12.8% for IGFBP-3. Based on Levy-Jennings plots, ∼5% of the plates used for IGF-I in the main study were out of compliance. Finally, location on a plate had small but significant effects on IGF-I level. Together, these results highlight the need for care in large studies of putative biomarkers for cancer risk and illustrate some probable sources of heterogeneity in past epidemiologic studies of the IGF axis and cancer. (Cancer Epidemiol Biomarkers Prev 2007;16(5):1017–22)
Etho-Archaeology of Manual Laterality: Well Digging by Wild Chimpanzees
Authors: McGrew W.C. , Marchant L.F. , Hunt K.D.
Published: May 2007

We present the first indirect test of manually lateralized behaviour in non-human primates, based on wells dug for drinking water by wild chimpanzees (Pan troglodytes schweinfurthii). Apes at Toro-Semliki Wildlife Reserve, in Uganda, dig bimanually in sandy riverbeds, leaving behind paired piles of excavated sand. The volumes of left- versus right-side piles do not differ, suggesting a lack of behavioural laterality, but this needs to be verified by further, direct observational data.
Non-Hodgkin Lymphomas Concurrent with HHV8-Associated Kaposi’s Sarcoma in the Same Lymph Node in AIDS and Non-AIDS Patients
Authors: Licci Stefano , D’Antonio Antonio , Boscaino Amedeo , Morelli Luca , Piscioli Francesco , Abbate Isabella , Perrone Donnorso Raffaele , Del Nonno Franca
Published: May 2007

Background: The association between lymphomas and Kaposi’s sarcoma has been described since 1920. The simultaneous presence of the 2 pathologic entities within the same lymph node is a rare and interesting occurrence. In the few cases described, the presence of human herpesvirus 8 (HHV8) and Epstein-Barr virus (EBV) in the different neoplastic areas was investigated only by immunohistochemistry and in situ hybridization studies. Methods: Two cases of concurrent non-Hodgkin lymphoma and Kaposi’s sarcoma in the same lymph node are described: a diffuse large B cell lymphoma in an AIDS patient and a T cell-rich large B cell lymphoma in a HIV-negative patient, complete with the clinical, immunohistological and molecular features, the latter ones defined after isolation of the different neoplastic areas by laser capture microdissection. Results: Polymerase chain reaction assays revealed HHV8 DNA sequences only in the microdissected Kaposi’s sarcoma areas and EBV DNA sequences only in the lymphomatous areas in both cases, confirming the HHV8 infection only in the neoplastic sarcomatous cells and evidencing the EBV infection only in the lymphomatous cells. Conclusion: This study represents a further confirmation of the supposed different etiopathogenic mechanisms of the 2 neoplasias, suggesting a coincidental occurrence even when localized in the same lymph node, independently from HIV infection.
Is Bone Marrow Biopsy Obligatory in All Patients with Non-Hodgkin’s Lymphoma?
Authors: Bairey Osnat , Shpilberg Ofer
Published: May 2007

Bone marrow biopsy (BMB) is recommended as a part of the workup diagnosis in all patients with non-Hodgkin’s lymphoma (NHL). This is an invasive procedure that is mostly stressful for the patient and very rarely is associated with severe bleeding. We suggest that the clinician needs to weigh up the potential benefit of this procedure in each case in terms of changing therapeutic approach and prognosis. We think BMB is not mandatory in every patient with NHL and suggest recommendations for which patients we should continue to perform this procedure on.
Molecular Characterization of Arginine Kinase, an Allergen from the Shrimp Litopenaeus vannamei
Authors: García-Orozco Karina D. , Aispuro-Hernández Emmanuel , Yepiz-Plascencia Gloria , Calderón-de-la-Barca Ana María , Sotelo-Mundo Rogerio R.
Published: May 2007

Background: Consumption of seafood can produce allergic symptoms in susceptible individuals and crustacean allergies are the most frequently reported causes of allergic reactions. Methods: An allergen from the muscle of the white shrimp Litopenaeus vannamei was purified by ion exchange chromatography and identified by mass spectrometry of tryptic peptides and its specific enzymatic activity. Moreover, the corresponding full-length cDNA was obtained from an L. vannamei muscle cDNA library. Results: A 40-kDa protein was purified and identified as arginine kinase and its cDNA of 1.4 kb encoded a 356 amino acid protein. The obtained arginine kinase was recognized by IgE in serum from shrimp-allergic individuals using ELISA and immunoblotting analysis. Conclusions: This is the first allergen reported for the Pacific white shrimp species; it was named Lit v 2 and has a 96% identity to Pen m 2 from Penaeus monodon.
Anaphylaxis from Mandarin (Citrus reticulata): Identification of Potential Responsible Allergens
Authors: Ebo D.G. , Ahrazem O. , Lopez-Torrejon G. , Bridts C.H. , Salcedo G. , Stevens W.J.
Published: May 2007

We report on a patient with anaphylaxis from mandarin. Temporal relationship between consumption of the fruit, the presence of positive specific IgE, the positive skin test and the basophil activation test for mandarin strongly supported the diagnosis of an IgE-mediated allergy from mandarin. The lipid transfer protein allergen from mandarin fruit was isolated and characterized. Specific IgE levels and IgE immunodetection data indicated the patient’s sensitization to orange (Cit s 3) and mandarin (Cit r 3) lipid transfer protein allergens, as well as to germin-like (Cit s 1) allergen. These results were fully confirmed by skin prick test and basophil activation test (BAT) for lipid transfer proteins, and a BAT for Cit s 1. This case report has several particularities. First, in Central and Northern Europe, it is not widely appreciated that citrus fruits, particularly mandarin, can elicit anaphylaxis. Second, this case report re-emphasizes sensitization from lipid transfer proteins to predispose for severe allergic reactions. Finally, it provides an opportunity to summarize the applications of flow cytometry-assisted analysis and quantification of in vitro activated basophils in the diagnostic approach of anaphylaxis from food.
Hypersensitivity to Paracetamol in Asian Children with Early Onset of Nonsteroidal Anti-Inflammatory Drug Allergy
Authors: Kidon Mona Iancovici , Liew Woei Kang , Chiang Wen Chin , Lim Siok Hoon , Goh Anne , Tang Jenny Poh Lin , Chay Oh Moh
Published: May 2007

Background: The published incidence of paracetamol cross-reactivity in adults and adolescents with nonsteroidal anti-inflammatory drug (NSAID) reactions is low and all data on such reactions in young children is sparse. The study aim was to characterize the clinical presentation and cross-reactivity with paracetamol in patients with a reported onset of NSAID hypersensitivity before 6 years of age. Methods: A retrospective case review was done of patients with cross-reactive hypersensitivity reactions to antipyretic/analgesic medications from the pediatric allergy clinic of the Kendang Kerbau Hospital, Singapore. Included patients reported the onset of such reactions before 6 years of age. Hypersensitivity was established through a detailed history of recurrent reactions to NSAIDs or an oral provocation test. Results: Eighteen patients fulfilled the diagnostic criteria within the study period. Eighty-three percent had cross-reactive reactions with paracetamol. When compared to the group of children with later onset of NSAID hypersensitivity, children with onset before 6 years of age had a significantly increased likelihood of reacting to paracetamol (odds ratio 9.6, 95% confidence interval 1.6–58.0, p < 0.05). Conclusion: Paracetamol seems to be a major eliciting drug in this group of children.
Detection of Dermatophagoides farinae in the Dust of Air Conditioning Filters
Authors: Liu Zhigang , Bai Yu , Ji Kunmei , Liu Xiaoyu , Cai Chengyu , Yu Haiqiong , Li Meng , Bao Ying , Lian Yuyin , Gao Bo
Published: May 2007

Background: The allergenic dust mite species Dermatophagoides pteronyssinus and Dermatophagoides farinae generally inhabit warm moist environments. This study tested the hypothesis that these allergenic species may thrive in air conditioner filters. Methods: A year-long investigation of the dust mite population densities and species identities living in air conditioner filters in Shenzhen City in Southern China was performed. Additional data describing the levels of major dust mite allergen proteins from samples collected in July and August 2004 were analyzed. Genetic polymorphism analysis of Der f 1 and Der f 2 genes in the collected animals was also conducted. Results: Our investigation revealed that larval dust mites started to grow in March, from which time their populations proceeded to steadily increase until reaching their population zenith in July and August. The dust mite populations decreased sharply in October and live dust mites were no longer observed in the winter. Among the mites collected in July and August, 30.1 and 25.8% were of the species D. farinae. The concentration of Der f 1 was 3.04 ± 1.75 and 3.21 ± 1.84 µg/g dust in July and August, respectively, and that of Der f 2 was 2.15 ± 0.82 and 2.04 ± 1.15 µg/g dust. Four types of Der f 1 and 5 types of Der f 2 cDNA sequences were cloned from collected Der f mites. Their sequences were highly homologous with those previously published in GenBank (No. AB034946.1 and No. AB195580.1). Conclusions: This research demonstrated that Der f allergens exist in the dust of air conditioner filters in this area.
CX3CR1 Polymorphisms Are Associated with Atopy but Not Asthma in German Children
Authors: Depner Martin , Kormann Michael S.D. , Klopp Norman , Illig Thomas , Vogelberg Christian , Weiland Stephan K. , von Mutius Erika , Combadière Christophe , Kabesch Michael
Published: May 2007

Chemokines and their receptors are involved in many aspects of immunity. Chemokine CX3CL1, acting via its receptor CX3CR1, regulates monocyte migration and macrophage differentiation as well as T cell-dependent inflammation. Two common, nonsynonymous polymorphisms in CX3CR1 have previously been shown to alter the function of the CX3CL1/CX3CR1 pathway and were suggested to modify the risk for asthma. Using matrix-assisted laser desorption/ionization time-of-flight technology, we genotyped polymorphisms Val249Ile and Thr280Met in a cross-sectional population of German children from Munich (n = 1,159) and Dresden (n = 1,940). For 249Ile an odds ratio of 0.77 (95% confidence interval 0.63–0.96; p = 0.017) and for 280Met an odds ratio of 0.71 (95% confidence interval 0.56–0.89; p = 0.004) were found with atopy in Dresden but not in Munich. Neither polymorphism was associated with asthma. Thus, amino acid changes in CX3CR1 may influence the development of atopy but not asthma in German children. Potentially, other factors such as environmental effects may modify the role of CX3CR1 polymorphisms.
True Hermaphroditism in a Phenotypic Male without Ambiguous Genitalia: An Unusual Presentation at Puberty
Authors: Alonso Guillermo , Pasqualini Titania , Busaniche Julio , Ruiz Eduardo , Chemes Héctor
Published: May 2007

True hermaphroditism usually appears with ambiguous genitalia requiring extensive evaluation during the neonatal period. There have been occasional cases with better differentiation of external genitalia, leading to delays in diagnosis. We report the case of an adolescent boy with true hermaphroditism who presented with normal external genitalia and no sexual ambiguity. He was referred due to progressive gynecomastia and arrest of puberty. He presented at the age of 16 years for gynecomastia of rapid progression with normal penile development and both gonads in scrotum and normal testosterone and increased gonadotropin levels. Gonadal ultrasound scan was compatible with testicular and ovarian tissues in scrotum, and the karyotype showed two cellular lines (46,XX/46,XY). Gonadal histology revealed bilateral ovotestes. A genotype polymerase chain reaction mediated analysis using seven microsatellite markers did not confirm chimerism. Clinical findings and mechanism of generation are discussed.