bluuebunny/crossref_metadata_2025 huggingface dataset:
An Energy‐Work Relationship Integration Scheme for Nonconservative Hamiltonian Systems
Authors: Jingli Fu , Benyong Chen , Fengping Xie
Published: July 2008

This letter focuses on studying a new energy‐work relationship numerical integration scheme of nonconservative Hamiltonian systems. The signal‐stage, multistage, and parallel composition numerical integration schemes are presented for this system. The high‐order energy‐work relation scheme of the system is constructed by a parallel connection of n multistage scheme of order 2 which its order of accuracy is 2n. The connection, which is discrete analog of usual case, between the change of energy and work of nonconservative force is obtained for nonconservative Hamiltonian systems.This letter also shows that the more the stages of the schemes are, the less the error rate of the scheme is for nonconservative Hamiltonian systems. Finally, an applied example is discussed to illustrate these results.
Thermal‐Fluid Transport Phenomena between Twin Rotating Parallel Disks
Authors: Torii Shuichi , Yang Wen-Jei
Published: July 2008

This paper investigates thermal‐fluid transport phenomena in laminar flow between twin rotating parallel disks from whose center a circular jet is impinged on the heated horizontal bottom disk surface. Emphasis is placed on the effects of the Reynolds number, rotation speed, and disk spacing on both the formations of velocity and thermal fields and the heat transfer rate along the heated wall surface. The governing equations are discretized by means of a finite‐difference technique and are numerically solved to determine the distributions of velocity vector and fluid temperature under the appropriate boundary conditions. It is found from the study that (i) the recirculation zone which appears on the bottom disk moves along the outward direction with an increase in the Reynolds number, (ii) when the Reynolds number is increased, heat transfer performance is intensified over the whole disk surface and the minimum value of the heat transfer rate moves in the downstream direction, and (iii) the heat transfer rate is induced due to the disk rotation, whose effect becomes larger due to the upper disk rotation.
Experimental Results for the Multipath Performance of Galileo Signals Transmitted by GIOVE‐A Satellite
Authors: Simsky Andrew , Mertens David , Sleewaegen Jean-Marie , Hollreiser Martin , Crisci Massimo
Published: July 2008

Analysis of GIOVE‐A signals is an important part of the
in‐orbit validation phase of the Galileo program.
GIOVE‐A transmits the ranging signals using all the
code modulations currently foreseen for the future
Galileo and provides a foretaste of their performance in
real‐life applications. Due to the use of advanced code
modulations, the ranging signals of Galileo
provide significant improvement of the multipath performance
as compared to current GPS. In this paper, we summarize the
results of about 1.5 years of observations using the
data from four antenna sites. The analysis of the elevation
dependence of averaged multipath errors and the multipath
time series for static data indicate significant suppression
of long‐range multipath by the best Galileo codes. The E5AltBOC
signal is confirmed to be a multipath suppression champion
for all the data sets. According to the results of the observations,
the Galileo signals can be classified into 3 groups: high‐performance
(E5AltBOC, L1A, E6A), medium‐performance (E6BC, E5a, E5b)
and an L1BC signal, which has the lowest performance among
Galileo signals, but is still better than GPS‐CA. The car
tests have demonstrated that for kinematic multipath the intersignal
differences are a lot less pronounced. The phase multipath
performance is also discussed.
Thermal Conductivity in Nanoporous Gold Films during Electron‐Phonon Nonequilibrium
Authors: Hopkins Patrick E. , Norris Pamela M. , Phinney Leslie M. , Policastro Steven A. , Kelly Robert G.
Published: July 2008

The reduction of nanodevices has given recent attention to nanoporous materials due to their structure and geometry. However, the thermophysical properties of these materials are relatively unknown. In this article, an expression for thermal conductivity of nanoporous structures is derived based on the assumption that the finite size of the ligaments leads to electron‐ligament wall scattering. This expression is then used to analyze the thermal conductivity of nanoporous structures in the event of electron‐phonon nonequilibrium.
Pricing Participating Products under a Generalized Jump‐Diffusion Model
Authors: Siu Tak Kuen , Lau John W. , Yang Hailiang
Published: July 2008

We propose a model for valuing participating life insurance products under a generalized jump‐diffusion model with a Markov‐switching compensator. It also
nests a number of important and popular models in finance, including the classes
of jump‐diffusion models and Markovian regime‐switching models. The Esscher
transform is employed to determine an equivalent martingale measure. Simulation
experiments are conducted to illustrate the practical implementation of the model
and to highlight some features that can be obtained from our model.
A Fluid Model for a Relay Node in an Ad Hoc Network: Evaluation of Resource Sharing Policies
Authors: Mandjes Michel , Scheinhardt Werner
Published: July 2008

Fluid queues offer a natural framework for analyzing waiting times in a relay node of an ad hoc network. Because of the resource sharing policy applied, the input and output of these queues are coupled. More specifically, when there are n users who wish to transmit data through a specific node, each of them obtains a share 1/(n + W) of the service capacity to feed traffic into the queue of the node, whereas the remaining fraction W/(n + W) is used to serve the queue; here W > 0 is a free design parameter. Assume now that jobs arrive at the relay node according to a Poisson process, and that they bring along exponentially distributed amounts of data. The case W = 1 has been addressed before; the present paper focuses on the intrinsically harder case W > 1, that is, policies that give more weight to serving the queue. Four performance metrics are considered: (i) the stationary workload of the queue, (ii) the queueing delay, that is, the delay of a “packet” (a fluid particle) that arrives at an arbitrary point in time, (iii) the flow transfer delay, (iv) the sojourn time, that is, the flow transfer time increased by the time it takes before the last fluid particle of the flow is served. We explicitly compute the Laplace transforms of these random variables.
Subwavelength Grating Structures in Silicon‐on‐Insulator Waveguides
Authors: Schmid J. H. , Cheben P. , Janz S. , Lapointe J. , Post E. , Delâge A. , Densmore A. , Lamontagne B. , Waldron P. , Xu D.-X.
Published: July 2008

First implementations of subwavelength gratings (SWGs) in silicon‐on‐insulator (SOI) waveguides are discussed and demonstrated by experiment and simulations. The subwavelength effect is exploited for making antireflective and highly reflective waveguide facets as well as efficient fiber‐chip coupling structures. We demonstrate experimentally that by etching triangular SWGs into SOI waveguide facets, the facet power reflectivity can be reduced from 31% to <2.5%. Similar structures using square gratings can also be used to achieve high facet reflectivity. Finite
difference time‐domain simulations show that >94% facet reflectivity can be achieved with square SWGs for 5 μm thick SOI waveguides. Finally, SWG fiber‐chip couplers for SOI photonic wire waveguides are introduced, including design,
simulation, and first experimental results.
Bowel Preparation for Colonoscopy with Sodium Phosphate Solution versus Polyethylene Glycol-Based Lavage: A Multicenter Trial
Authors: Schanz S. , Kruis W. , Mickisch O. , Küppers B. , Berg P. , Frick B. , Heiland G. , Hüppe D. , Schenck B. , Horstkotte H. , Winkler A.
Published: July 2008

Background: Adequate bowel preparation is essential for accurate colonoscopy. Both oral sodium phosphate (NaP) and polyethylene glycol-based lavage (PEG-ELS) are used predominantly as bowel cleansing modalities. NaP has gained popularity due to low drinking volume and lower costs. The purpose of this randomized multicenter observer blinded study was to compare three groups of cleansing (NaP, NaP + sennosides, PEG-ELS + sennosides) in reference to tolerability, acceptance, and cleanliness. Patient and Methods: 355 outpatients between 18 and 75 years were randomized into three groups (A, B, C) receiving NaP = A, NaP, and sennosides = B or PEG-ELS and sennosides = C. Gastroenterologists performing colonoscopies were blinded to the type of preparation. All patients documented tolerance and adverse events. Vital signs, premedication, completeness, discomfort, and complications were recorded. A quality score (0–4) of cleanliness was generated.Results: The three groups were similar with regard to age, sex, BMI, indication for colonoscopy, and comorbidity. Drinking volumes (L) (A = 4.33 + 1.2, B = 4.56 + 1.18, C = 4.93 + 1.71) were in favor of NaP (P= .005). Discomfort from ingested fluid was recorded in A = 39.8% (versus C:P= .015), B = 46.6% (versus C:P= .147), and C = 54.6%. Differences in tolerability and acceptance between the three groups were statistically not significant. No differences in adverse events and the cleanliness effects occurred in the three groups (P= .113). The cleanliness quality scores 0–2 were calculated in A: 77.7%, B: 86.7%, and C: 85.2%.Conclusions: These data fail to demonstrate significant differences in tolerability, acceptance, and preparation quality between the three types of bowel preparation for colonoscopy. Cleansing with NaP was not superior to PEG-ELS.
Performance of Composite Implicit Time Integration Scheme for Nonlinear Dynamic Analysis
Authors: Matias Silva William Taylor , Mendes Bezerra Luciano
Published: July 2008

This paper presents a simple implicit time integration scheme for transient response solution of structures under large deformations and long‐time durations. The authors focus on a practical method using implicit time integration scheme applied to structural dynamic analyses in which the widely used Newmark time integration procedure is unstable, and not energy‐momentum conserving. In this integration scheme, the time step is divided in two substeps. For too large time steps, the method is stable but shows excessive numerical dissipation. The influence of different substep sizes on the numerical dissipation of the method is studied throughout three practical examples. The method shows good performance and may be considered good for nonlinear transient response of structures.
High-Power Hybrid Mode-Locked External Cavity Semiconductor Laser Using Tapered Amplifier with Large Tunability
Authors: Schmitt-Sody Andreas , Velten Andreas , Liu Ye , Arissian Ladan , Diels Jean-Claude
Published: July 2008

We report on hybrid mode-locked laser operation of a tapered semiconductor amplifier in an external ring cavity, generating pulses as short as 0.5 ps at 88.1 MHz with an average power of 60 mW. The mode locking is achieved through a combination of a multiple quantum well saturable absorber (>10% modulation depth) and an RF current modulation. This designed laser has 20 nm tuning bandwidth in continuous wave and 10 nm tuning bandwidth in mode locking around 786 nm center wavelength at constant temperature.
Optical Biomedical Diagnostics: Sensors with Optical Response Based on Two‐Photon Excited Luminescent Dyes for Biomolecules Detection
Authors: Yashchuk V. M. , Yarmoluk S. M. , Kudrya V. Yu. , Losytskyy M. Yu. , Tokar V. P. , Kravchenko V. M. , Kovalska V. B. , Balanda A. O. , Kryvorotenko D. V.
Published: July 2008

The spectral properties of novel styryl dyes developed for the biomacromolecules (such as DNA) detection and imaging were investigated. The energy structures of dye molecules were examined. The spectral data prove that dyes aggregate and interact with DNA. The essential increase of the fluorescence intensity of dyes in the presence of DNA was observed. The photostability and phototoxic influence on the DNA of several styryl dyes were studied by analyzing absorption, fluorescence, and phosphorescence spectra of these dyes and dye‐DNA systems. Changes of the optical density value of dye‐DNA solutions caused by the irradiation were fixed in the DNA and dye absorption wavelength regions. Fluorescence emission of dye‐DNA complexes upon two‐photon excitation at wavelength 1064 nm with the 20‐nanosecond pulsed YAG:Nd3+ laser and at 840 nm with the 90 famtosecond pulsed Ti:sapphire laser was registered. The values of two‐photon absorption cross‐sections of dye‐DNA complexes were evaluated.
A Recursive Fuzzy System for Efficient Digital Image Stabilization
Authors: Kyriakoulis Nikolaos , Gasteratos Antonios
Published: July 2008

A novel digital image stabilization technique is proposed
in this paper. It is based on a fuzzy Kalman compensation
of the global motion vector (GMV), which is estimated in the
log‐polar plane. The GMV is extracted using four local motion
vectors (LMVs) computed on respective subimages in the logpolar
plane. The fuzzy Kalman system consists of a fuzzy system
with the Kalman filter′s discrete time‐invariant definition. Due
to this inherited recursiveness, the output results into smoothed
image sequences. The proposed stabilization system aims to
compensate any oscillations of the frame absolute positions, based
on the motion estimation in the log‐polar domain, filtered by the
fuzzy Kalman system, and thus the advantages of both the fuzzy
Kalman system and the log‐polar transformation are exploited.
The described technique produces optimal results in terms of the
output quality and the level of compensation.
Scalable Video Streaming for Single‐Hop Wireless Networks Using a Contention‐Based Access MAC Protocol
Authors: Lertsutthiwong Monchai , Nguyen Thinh , Fern Alan
Published: July 2008

Limited bandwidth and high packet loss rate pose a serious challenge for video streaming applications over wireless networks. Even when packet loss is not present, the bandwidth fluctuation, as a result of an arbitrary number of active flows in an IEEE 802.11 network, can significantly degrade the video quality. This paper aims to enhance the quality of video streaming applications in wireless home networks via a joint optimization of video layer‐allocation technique, admission control algorithm, and medium access control (MAC) protocol. Using an Aloha‐like MAC protocol, we propose a novel admission control framework, which can be viewed as an optimization problem that maximizes the average quality of admitted videos, given a specified minimum video quality for each flow. We present some hardness results for the optimization problem under various conditions and propose some heuristic algorithms for finding a good solution. In particular, we show that a simple greedy layer‐allocation algorithm can perform reasonably well, although it is typically not optimal. Consequently, we present a more expensive heuristic algorithm that guarantees to approximate the optimal solution within a constant factor. Simulation results demonstrate that our proposed framework can improve the video quality up to 26% as compared to those of the existing approaches.
A New Resistance Formulation for Carbon Nanotubes
Authors: He Ji-Huan
Published: July 2008

A new resistance formulation for carbon nanotubes is suggested using fractal approach. The new formulation is also valid for other nonmetal conductors including nerve fibers, conductive polymers, and molecular wires. Our theoretical prediction agrees well with experimental observation.
Serum Insulin-Like Growth Factor-I and Platelet-Derived Growth Factor as Biomarkers of Breast Cancer Prognosis
Authors: Pasanisi Patrizia , Venturelli Elisabetta , Morelli Daniele , Fontana Luigi , Secreto Giorgio , Berrino Franco
Published: July 2008

Epidemiologic studies have shown that growth factors and inflammatory mechanisms may affect breast cancer risk and prognosis. The present analysis on 110 postmenopausal breast cancer patients tested if serum insulin-like growth factor I (IGF-I), platelet-derived growth factor (PDGF), fructosamine, and C-reactive protein, a serum marker of inflammation, are associated with breast cancer relapse. The risk of adverse events after 5.5 years of follow-up was examined by Cox proportional hazards modeling, controlling for hormone receptor status, stage at diagnosis, and for body weight and serum testosterone level, which were known to significantly affect prognosis. PDGF and, to a lesser extent, IGF-I were positively but not significantly associated with the risk of breast cancer recurrence. By combining PDGF and IGF-I, however, the adjusted hazard ratio of recurrence among the women with both PDGF and IGF-I levels > their median values (respectively, 9.3 and 174.4 ng/mL) was 6.4 (95% confidence interval, 1.5-26.7) compared with the women with PDGF and IGF-I levels ≤ their median values. Fructosamine and C-reactive protein were not associated with recurrences. The results suggest that PDGF may be an important prognostic factor for breast cancer and that IGF-I may increase the risk of recurrence in the presence of high PDGF levels. (Cancer Epidemiol Biomarkers Prev 2008;17(7):1719–22)
Serum β-Glucuronidase Activity in Response to Fruit and Vegetable Supplementation: A Controlled Feeding Study
Authors: Maruti Sonia S. , Chang Jyh-Lurn , Prunty Jo Ann , Bigler Jeannette , Schwarz Yvonne , Li Shuying S. , Li Lin , King Irena B. , Potter John D. , Lampe Johanna W.
Published: July 2008

Background: Fruit and vegetable (F&V) intake may lower the risk of some cancers. One hypothesized, but understudied, chemopreventive mechanism is that plant food constituents inhibit β-glucuronidase, an acid hydrolase that deconjugates glucuronides.

Methods: We conducted a crossover feeding trial in 63 healthy women and men ages 20 to 40 years to examine the effect of diet on serum β-glucuronidase activity. Participants were randomized to two 2-week experimental diets with an intervening washout period: a diet high in selected citrus fruit, crucifers, and soy (F&V) and a diet devoid of fruits, vegetables, and soy (basal). Serum β-glucuronidase activity was measured during the preintervention, F&V, and basal periods. Linear mixed models were used to obtain effect estimates and 95% confidence intervals (95% CI).

Results: We observed statistically significantly higher β-glucuronidase activity during the F&V than the basal diet (ratio, F&V versus basal diet, 1.09; 95% CI, 1.05-1.13; P < 0.01). These results were probably due to decreased β-glucuronidase activity during the basal diet (ratio, basal period versus preintervention, 0.93; 95% CI, 0.87-0.98; P = 0.01) rather than increased enzyme activity during the F&V diet (ratio, F&V period versus preintervention, 1.01; 95% CI, 0.96-1.06; P = 0.64). Response to the experimental diet did not differ by sex (Pinteraction = 0.30), but there was a suggestion of a short-term diet effect at 8 versus 15 days (Pinteraction = 0.06).

Conclusion: This intervention of selected F&V did not lower β-glucuronidase activity. Further investigation is needed regarding what other foods and phytochemicals may influence β-glucuronidase activity and effect modifiers of this relation. (Cancer Epidemiol Biomarkers Prev 2008;17(7):1808–12)
Racial/Ethnic Disparities in the Use of Nicotine Replacement Therapy and Quit Ratios in Lifetime Smokers Ages 25 to 44 Years
Authors: Fu Steven S. , Kodl Molly M. , Joseph Anne M. , Hatsukami Dorothy K. , Johnson Eric O. , Breslau Naomi , Wu Baolin , Bierut Laura
Published: July 2008

We examined racial/ethnic variations in the use of nicotine replacement therapy (NRT) and quit ratios among Caucasian, African American, Asian, and Latino lifetime smokers ages 25 to 44 years. We conducted cross-sectional analyses using data from individuals (n = 27,031) screened for enrollment in the Collaborative Study of the Genetics of Nicotine Dependence. Participants were randomly sampled from three Midwestern metropolitan areas using Health Maintenance Organization membership lists in Detroit, MI and Minneapolis, MN and a driver’s license registry in St. Louis, MO from March 2003 to August 2005. A telephone survey collected information on smoking history, previous quit attempts, and sociodemographic characteristics. Among lifetime smokers (n = 9,216), univariate analysis indicated that African Americans (22%) and Latinos (22%) were significantly less likely to report having ever used NRT for smoking cessation than Caucasians (31%). Asians (22%) also reported lower rates of using NRT than Caucasians, but this difference was marginally significant (P = 0.06). These disparities persisted in multivariate analysis for African Americans [adjusted odds ratio (OR), 0.76; 95% confidence interval (95% CI), 0.63-0.91; P < 0.01] but not for Latinos (adjusted OR, 0.76; 95% CI, 0.54-1.06; P = 0.11) or Asians (adjusted OR, 0.98; 95% CI, 0.60-1.60; P = 0.95). As measured by the quit ratio, African Americans (35%) were less likely to have quit smoking than Caucasians (52%). This disparity persisted in multivariate logistic regression (adjusted OR, 0.66; 95% CI, 0.56-0.78; P < 0.001). Asian and Latino smokers were as likely as Caucasians to report smoking cessation. Future prospective studies are needed to assess whether lower utilization of cessation treatments such as NRT contribute to the observed disparity in quit ratios for African Americans. (Cancer Epidemiol Biomarkers Prev 2008;17(7):1640–7)
Community-Based Mass Ultrasonographic Screening of Hepatocellular Carcinoma among Thrombocytopenic Adults
Authors: Lu Sheng-Nan , Wang Jing-Houng , Chen Pao-Fei , Tung Hung-Da , Tseng Po-Lin , Hung Chao-Hung , Kee Kwong-Ming , Chen Chien-Hung , Chang Kuo-Chin , Lee Chuan-Mo , Changchien Chi-Sin , Chen Yao-Der , Tsai Lin-San , Chen Tony Hsiu-Hsi
Published: July 2008

Thrombocytopenia has been reported as a valid surrogate for liver cirrhosis and could be used to identify groups at high risk of hepatocellular carcinoma (HCC) for ultrasonographic (US) screening. We designed this two-stage community-based screening for HCC. In 2004, subjects (ages ≥40 years) were invited to undergo comprehensive health examinations, with 17,551 men (ages 63.0 ± 11.5 years) and 39,151 women (ages 59.9 ± 11.7 years) participating. Subjects with platelet counts <150 × 109/L or α-fetoprotein (AFP) >20 ng/mL were enrolled for the second-stage US screening; 3,242 subjects (5.7%; male/female, 1,415/1,827; age 66 ± 10 years) were candidates for US screening and 2,983 (92.2%) responded. Of 137 suspected cases, 124 (90.5%) complied with referral for confirmation and 72 (58.1%) were confirmed to be HCC cases (male/female, 41/31; age 68.1 ± 8.8 years). Screening with AFP, thrombocytopenia, or both could identify 0.64% (n = 364), 5.33% (n = 3,205), and 5.7% (n = 3,242) of the high-risk subjects from the population, estimated to include 50.5%, 54.5%, and 71.3% of all HCC cases. Among confirmed patients, tumor diameters were <3 cm for the 27 (37.5%) patients and 3 to 5 cm for the 23 (31.9%) patients. Only 5 (6.9%) patients' conditions were too advanced to be actively treated. This study enrolled only 5.7% of the participants for US, which cover 64.7% to 71.3% of the HCC cases. Most (93%) of the detected cases were caught early enough to undergo effective treatment modalities. This HCC screening protocol should be feasible, economical, and effective. (Cancer Epidemiol Biomarkers Prev 2008;17(7):1813–21)
Effect of Raloxifene on Mammographic Density and Breast Magnetic Resonance Imaging in Premenopausal Women at Increased Risk for Breast Cancer
Authors: Eng-Wong Jennifer , Orzano-Birgani Jennifer , Chow Catherine K. , Venzon David , Yao Jianhua , Galbo Claudia E. , Zujewski Jo Anne , Prindiville Sheila
Published: July 2008

Background: Mammographic density is a risk factor for breast cancer. Mammographic density and breast magnetic resonance imaging (MRI) volume (MRIV) assess the amount of fibroglandular tissue in the breast. Mammographic density and MRIV can be modulated with hormonal interventions, suggesting that these imaging modalities may be useful as surrogate endpoint biomarkers for breast cancer chemoprevention trials. We evaluated the effect of raloxifene on mammographic density and MRIV in premenopausal women at increased risk for breast cancer.

Methods: Mammograms and MRI were obtained at baseline and after 1 and 2 years of 60 mg raloxifene by mouth daily for 27 premenopausal women. Mammographic percent dense area was calculated using a semiquantitative thresholding technique. T1-weighted spoiled gradient-echo MRI with fat suppression was used to determine breast MRIV using a semiautomatic method. Mean change in mammographic density and median change in MRIV were assessed by the Wilcoxon signed-rank test.

Results: No significant change in mammographic density was seen after treatment with raloxifene. Mean change after 1 year was 1% [95% confidence interval (95% CI), −3 to +5] and after 2 years was 1% (95% CI, −2 to +5). MRIV decreased on raloxifene. Median relative change in MRIV after 1 year was -17% (95% CI, -28 to -9; P = 0.0017) and after 2 years was -16% (95% CI, -31 to -4; P = 0.0004).

Conclusions: In high-risk premenopausal women, mammographic density did not change on raloxifene, whereas MRIV significantly declined. Our findings suggest that MRIV is a promising surrogate biomarker in premenopausal women at increased risk for breast cancer and should be investigated further in breast cancer prevention trials. (Cancer Epidemiol Biomarkers Prev 2008;17(7):1696–701)
Cervical and Vulvar Cancer Risk in Relation to the Joint Effects of Cigarette Smoking and Genetic Variation in Interleukin 2
Authors: Hussain Shehnaz K. , Madeleine Margaret M. , Johnson Lisa G. , Du Qin , Malkki Mari , Wilkerson Hui-Wen , Farin Federico M. , Carter Joseph J. , Galloway Denise A. , Daling Janet R. , Petersdorf Effie W. , Schwartz Stephen M.
Published: July 2008

Cigarette smoking is an established cofactor to human papillomavirus (HPV) in the development of cervical and vulvar squamous cell carcinoma (SCC), and may influence risk through an immunosuppressive pathway. Genetic variation in interleukin 2 (IL2), associated in some studies with the inhibition of HPV-targeted immunity, may modify the effect of smoking on the risk of HPV-related anogenital cancers. We conducted a population-based case-only study to measure the departure from a multiplicative joint effect of cigarette smoking and IL2 variation on cervical and vulvar SCC. Genotyping of the four IL2 tagSNPs (rs2069762, rs2069763, rs2069777, and rs2069778) was done in 399 cervical and 486 vulvar SCC cases who had been interviewed regarding their smoking history. Compared with cases carrying the rs2069762 TT genotype, we observed significant departures from multiplicativity for smoking and carriership of the TG or GG genotypes in vulvar SCC risk [interaction odds ratio (IOR), 1.67; 95% confidence interval (CI), 1.16-2.41]. Carriership of one of three diplotypes, together with cigarette smoking, was associated with either a supramultiplicative (TGCT/GGCC; IOR, 2.09; 95% CI, 0.98-4.46) or submultiplicative (TTCC/TGTC; IOR, 0.37; 95% CI, 0.16-0.85 or TGCT/TGCC; IOR, 0.37; 95% CI, 0.15-0.87) joint effect in vulvar cancer risk. For cervical SCC, departure from multiplicativity was observed for smokers homozygous for the rs2069763 variant allele (TT versus GG or GT genotypes; IOR, 1.87; 95% CI, 1.00-3.48), and for carriership of the TTCC/TTCC diplotype (IOR, 2.08; 95% CI, 1.01-4.30). These results suggest that cervical and vulvar SCC risk among cigarette smokers is modified by genetic variation in IL2. (Cancer Epidemiol Biomarkers Prev 2008;17(7):1790–9)
Sp1, a New Biomarker That Identifies a Subset of Aggressive Pancreatic Ductal Adenocarcinoma
Authors: Jiang Naomi Y. , Woda Bruce A. , Banner Barbara F. , Whalen Giles F. , Dresser Karen A. , Lu Di
Published: July 2008

Pancreatic adenocarcinoma is one of the leading causes of cancer-related deaths in the United States. Sp1 is a sequence-specific DNA binding protein that is important in the transcription of a number of regulatory genes involved in cancer cell growth, differentiation, and metastasis. In this study, we investigated Sp1 expression in pancreatic ductal adenocarcinoma and its association with clinical outcome. We studied 42 patients with primary pancreatic adenocarcinoma. The expression of Sp1 in pancreatic adenocarcinoma was evaluated by immunohistochemical staining. All 42 patients had clinical follow-up information and were evaluated for survival. Sp1 protein was aberrantly overexpressed in a subset of primary pancreatic adenocarcinoma. These tumors all developed metastasis, whereas none of the primary tumors without lymph node metastasis showed Sp1 overexpression. Statistically, Sp1 overexpression was associated with higher stage, higher grade, and lymph node metastasis (P < 0.001, P = 0.036, and P < 0.0001, respectively). Additionally, patients of this subset had a much shorter overall survival than patients without Sp1 overexpression, as evidenced by Kaplan-Meier plots and the log-rank test (P = 0.002). The 5-year overall survival rate was 19% in patients with Sp1 overexpression, compared with 55% in patients without Sp1 overexpression. The median survival was only 13 months for patients with Sp1 overexpression, compared with 65 months for patients without Sp1 overexpression. In conclusion, Sp1 is a new biomarker that identifies a subset of pancreatic ductal adenocarcinoma with aggressive clinical behavior. It can be used at initial diagnosis of pancreatic adenocarcinoma to identify patients with an increased probability of cancer metastasis and much shortened overall survival. (Cancer Epidemiol Biomarkers Prev 2008;17(7):1648–52)
Human Papillomavirus Infection in Ulaanbaatar, Mongolia: A Population-Based Study
Authors: Dondog Bolormaa , Clifford Gary M. , Vaccarella Salvatore , Waterboer Tim , Unurjargal Davaajav , Avirmed Damdin , Enkhtuya Sharkhuu , Kommoss Friedrich , Wentzensen Nicolas , Snijders Peter J.F. , Meijer Chris J.L.M. , Franceschi Silvia , Pawlita Michael
Published: July 2008

Data on human papillomavirus (HPV) and cervical cancer burden in Central Asia are scarce. To investigate HPV infection in Ulaanbaatar, the capital of Mongolia, we obtained cervical cell specimens from a population of 969 women ages 15 to 59 years. DNA of 44 HPV types was detected using a GP5+/6+ PCR-based assay. Seropositivity for L1 proteins of HPV 16, 18, 31, 33, 45, 52, and 58 was assessed using multiplex HPV serology. Cytologic abnormalities were detected in 127 women (13.1%), among whom 6 cervical intraepithelial neoplasia grade 3 and 2 invasive cervical cancers were diagnosed. Overall HPV DNA prevalence was 35.0%, being highest (48.5%) in women ages <25 years. High-risk types were detected in 24.5% of women. HPV DNA prevalence declined with age but remained >25% in all age groups. HPV seroprevalence was also very high (38.0%) and increased steadily from 33.2% to 48.9% in women ages <25 and 50 to 59 years, respectively. However, the proportion of women positive for both HPV markers of any individual HPV type was low. HPV16 was the most frequently detected type by PCR (6.1%), serology (23.0%), or both (2.1%). Lifetime number of sexual partners and induced abortions were shown to be directly associated with HPV DNA and/or seroprevalence. HPV prevalence in Ulaanbaatar was higher than that detected by similar HPV testing protocols in other populations in Asia or elsewhere and would suggest an important, yet unquantified, cervical cancer burden. Improving cervical cancer prevention, through screening and HPV vaccination, is an important public health issue for Mongolia. (Cancer Epidemiol Biomarkers Prev 2008;17(7):1731–8)
Association of Aryl Hydrocarbon Receptor Gene Polymorphisms and Urinary 1-Hydroxypyrene in Polycyclic Aromatic Hydrocarbon–Exposed Workers
Authors: Bin Ping , Leng Shuguang , Cheng Juan , Dai Yufei , Huang Chuanfeng , Pan Zufei , Niu Yong , Duan Huawei , Li Haishan , Liu Qingjun , Chen Wen , Zheng Yuxin
Published: July 2008

Polycyclic aromatic hydrocarbons (PAH) in coke oven emissions could cause lung cancer in human. Individual's genotype of the metabolic enzymes and early biological changes were known to be associated with the susceptibility of cancer development. Knowledge of metabolic gene polymorphisms, which affect on the urinary 1-hydroxypyrene (1-OHP), could benefit us in understanding the interindividual difference in the mechanism of PAH-induced carcinogenesis. In this study, we investigated the association of aryl hydrocarbon receptor (AhR) gene polymorphisms and urinary 1-OHP. One hundred forty-seven workers exposed to PAH and 69 nonexposure workers were recruited. Seven tagging single nucleotide polymorphisms in AhR gene were selected by pariwise r2 method and minor allele frequency cutoff of 0.05 from Chinese genotype data in HapMap project. These seven tagging single nucleotide polymorphisms were genotyped by PCR-based methods. Multivariate analysis of covariance revealed that the levels of 1-OHP in PAH-exposed workers carrying genotype CT were lower than workers carrying wild genotype TT at loci rs10250822 and rs2282885 of AhR gene (P = 0.032 and 0.044, respectively). In PAH-exposed workers, the urinary 1-OHP levels showed a linear correlation (Ptrend = 0.041) with the genotypes at locus rs2282885, especially in low and moderate exposure groups. In contrast, no significant association was found between urinary 1-OHP level and AhR genotypes among nonexposed workers. Our findings indicated that polymorphisms of AhR gene were associated with the level of 1-OHP among PAH-exposed workers, suggesting that AhR-mediated signaling might contribute to individual susceptibility to PAH exposure. (Cancer Epidemiol Biomarkers Prev 2008;17(7):1702–8)
Breast Cancer Risk and Hormone Receptor Status in Older Women by Parity, Age of First Birth, and Breastfeeding: A Case-Control Study
Authors: Lord Sarah J. , Bernstein Leslie , Johnson Karen A. , Malone Kathleen E. , McDonald Jill A. , Marchbanks Polly A. , Simon Michael S. , Strom Brian L. , Press Michael F. , Folger Suzanne G. , Burkman Ronald T. , Deapen Dennis , Spirtas Robert , Ursin Giske
Published: July 2008

Background: Early age at first birth and multiparity reduce the risk of estrogen receptor-progesterone receptor (ERPR)–positive breast cancer, whereas breastfeeding reduces the risk of both ERPR-positive and ERPR-negative cancers.

Methods: We used multivariable logistic regression analysis to investigate whether age at first birth (<25 or ≥25 years) and breastfeeding (ever/never) modify the long-term effect of parity on risk of ERPR-positive and ERPR-negative cancer using 1,457 incident breast cancer cases and 1,455 controls ages ≥55 years who participated in the Women's Contraceptive and Reproductive Experiences Study.

Results: Women who gave birth before age 25 years had a 36% reduced risk of breast cancer compared with nulligravida that was not observed for women who started their families at an older age (Pheterogeneity = 0.0007). This protective effect was restricted to ERPR-positive breast cancer (Pheterogeneity = 0.004). Late age at first birth increased the risk of ERPR-negative cancers.

Additional births reduced the risk of ERPR-positive cancers among women with an early first birth (Ptrend = 0.0001) and among women who breastfed (Ptrend = 0.004) but not among older mothers or those who never breastfed. In women with a late first birth who never breastfed, multiparity was associated with increased risk of breast cancer.

Conclusions: These findings suggest that the effect of parity on a woman's long-term risk of breast cancer is modified by age at first full-term pregnancy and possibly by breastfeeding. (Cancer Epidemiol Biomarkers Prev 2008;17(7):1723–30)
Use of Common Medications and Breast Cancer Risk
Authors: Moysich Kirsten B. , Beehler Gregory P. , Zirpoli Gary , Choi Ji-Yeob , Baker Julie A.
Published: July 2008

Prescription and over-the-counter medications are widely used in the United States and many western countries. More than two-thirds of women ages >45 years, who are at greatest risk for breast cancer, take prescription medication. In light of the ubiquitous nature of medication use and the fact that breast cancer remains the most common cancer in women, research on the role of medication use in breast cancer etiology is warranted. We summarize the epidemiologic evidence on the association between breast cancer risk and use of common medications, including antibiotics, antidepressants, statins, antihypertensives, and nonsteroidal anti-inflammatory drugs. Overall, there is little evidence that would implicate the use of antibiotics, antidepressants, statins, and antihypertensives in the etiology of breast cancer. Although several prospective studies and a randomized low-dose aspirin chemoprevention trial have not shown lower risk of breast cancer among aspirin users, most studies that have examined the potential chemoprotective effect of nonsteroidal anti-inflammatory drugs have shown significant risk reductions for regular and prolonged use of these drugs. The existing literature on the role of medication use in breast carcinogenesis is complicated. Interpretation of the evidence is hampered due to major methodologic differences across studies, including exposure assessment, exposure classification, and adjustment for potential confounding variables. These differences largely stem from the fact that the majority of articles on this topic represent secondary data analyses from studies with inadequate information on exposure or confounders. Thus, future epidemiologic studies specifically designed to study these ubiquitous and biologically plausible exposures are warranted. (Cancer Epidemiol Biomarkers Prev 2008;17(7):1564–95)
Colorectal Cancer Test Use from the 2005 National Health Interview Survey
Authors: Shapiro Jean A. , Seeff Laura C. , Thompson Trevor D. , Nadel Marion R. , Klabunde Carrie N. , Vernon Sally W.
Published: July 2008

Background: Screening is effective in reducing colorectal cancer mortality. Recommended colorectal cancer screening options include a home fecal occult blood test (FOBT) or colorectal endoscopy (sigmoidoscopy or colonoscopy). Past surveys have indicated that colorectal cancer screening prevalence in the United States is low. The purpose of this analysis was to determine the prevalence of colorectal cancer test use in the United States by various factors and to examine reasons for not having a colorectal cancer test.

Methods: Data on respondents ages ≥50 years from the 2005 National Health Interview Survey (n = 13,269) were analyzed. The proportion of the U.S. population that had home FOBT within the past year or endoscopy within the past 10 years was examined by sociodemographic, health-care access, and other health-related factors. Reported reasons for not having FOBT or endoscopy were also analyzed.

Results: The age-standardized proportion of respondents who reported FOBT within the past year and/or endoscopy within the past 10 years was 50.0% [95% confidence interval (95% CI), 48.8-51.2]. Colorectal cancer testing rates were particularly low among people without health-care coverage (24.1%; 95% CI, 19.2-29.7) or without a usual source of health care (24.7%; 95% CI, 20.8-29.0). The most commonly reported reason for not having a colorectal cancer test was “never thought about it.”

Conclusions: In 2005, about half of Americans ages ≥50 years did not have appropriate colorectal cancer testing. Increased efforts to expand health-care coverage or to provide colorectal cancer tests to people without health-care coverage are needed to increase colorectal cancer screening. (Cancer Epidemiol Biomarkers Prev 2008;17(7):1623–30)
Extensive Metabolic Activation of the Tobacco-Specific Carcinogen 4-(Methylnitrosamino)-1-(3-Pyridyl)-1-Butanone in Smokers
Authors: Stepanov Irina , Upadhyaya Pramod , Carmella Steven G. , Feuer Rachel , Jensen Joni , Hatsukami Dorothy K. , Hecht Stephen S.
Published: July 2008

4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is a potent lung carcinogen present in both unburned tobacco and cigarette smoke. The sum of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) and its glucuronides, referred to as total NNAL, is an established urinary biomarker of human NNK uptake. Metabolic activation of NNK to DNA adducts proceeds via α-hydroxylation pathways, and 4-oxo-4-(3-pyridyl)butanoic acid (keto acid) and 4-hydroxy-4-(3-pyridyl)butanoic acid (hydroxy acid) are the principal end products of these pathways in rodents and primates. The purpose of this study was to determine NNK metabolic activation in smokers, as measured by the sum of keto acid and hydroxy acid, relative to total NNAL. To specifically identify NNK-derived keto acid and hydroxy acid, which are also formed from nicotine, we added [pyridine-D4]NNK to cigarettes that were originally low in NNK, and measured the deuterium-labeled metabolites in the urine of people who smoked these cigarettes. The total amount of [pyridine-D4]keto acid plus [pyridine-D4]hydroxy acid averaged 4.00 ± 2.49 nmol/24 h, whereas the average amount of total [pyridine-D4]NNAL was 0.511 ± 0.368 nmol/24 h. The results of this study show for the first time that NNK metabolic activation is a quantitatively significant pathway in smokers, accounting for ∼86% of total urinary excretion of NNK metabolites. The large interindividual variation in the excreted [pyridine-D4]keto acid and [pyridine-D4]hydroxy acid among 20 smokers strongly supports our hypothesis that some smokers activate NNK more extensively than others and that the ratio between biomarkers of metabolic activation and detoxification at a given dose of NNK could be a potential indicator of cancer risk.(Cancer Epidemiol Biomarkers Prev 2008;17(7):1764–73)
Performance of Amplified DNA in an Illumina GoldenGate BeadArray Assay
Authors: Cunningham Julie M. , Sellers Thomas A. , Schildkraut Joellen M. , Fredericksen Zachary S. , Vierkant Robert A. , Kelemen Linda E. , Gadre Madhura , Phelan Catherine M. , Huang Yifan , Meyer Jeffrey G. , Pankratz V. Shane , Goode Ellen L.
Published: July 2008

Whole genome amplification (WGA) offers a means to enrich DNA quantities for epidemiologic studies. We used an ovarian cancer study of 1,536 single nucleotide polymorphisms (SNPs) and 2,368 samples to assess performance of multiple displacement amplification (MDA) WGA using an Illumina GoldenGate BeadArray. Initial screening revealed successful genotyping for 93.4% of WGA samples and 99.3% of genomic samples, and 93.2% of SNPs for WGA samples and 96.3% of SNPs for genomic samples. SNP failure was predicted by Illumina-provided designability rank, %GC (P ≤ 0.002), and for WGA only, distance to telomere and Illumina-provided SNP score (P ≤ 0.002). Distance to telomere and %GC were highly correlated; adjustment for %GC removed the association between distance to telomere and SNP failure. Although universally high, per-SNP call rates were related to designability rank, SNP score, %GC, minor allele frequency, distance to telomere (P ≤ 0.01), and, for WGA only, Illumina-provided validation class (P < 0.001). We found excellent concordance generally (>99.0%) among 124 WGA:genomic replicates, 15 WGA replicates, 88 replicate aliquots of the same WGA preparation, and 25 genomic replicates. Where there was discordance, it was across WGA:genomic replicates but limited to only a few samples among other replicates suggesting the introduction of error. Designability rank and SNP score correlated with WGA:genomic concordance (P < 0.001). In summary, use of MDA WGA DNA is feasible; however, caution is warranted regarding SNP selection and analysis. We recommend that biological SNP characteristics, notably distance to telomere and GC content (<50% GC recommended), as well as Illumina-provided metrics be considered in the creation of GoldenGate assays using MDA WGA DNA. (Cancer Epidemiol Biomarkers Prev 2008;17(7):1781–9)
A Prospective Study of Bowel Motility and Related Factors on Breast Cancer Risk
Authors: Maruti Sonia S. , Lampe Johanna W. , Potter John D. , Ready Ann , White Emily
Published: July 2008

Background: Estrogen is an established risk factor for breast cancer. Greater bowel motility has been associated with increased estrogen excretion and lower serum estrogen levels, suggesting that it may influence breast cancer risk. However, only one other epidemiologic study thus far, to our knowledge, has examined the relation between bowel motility and breast cancer risk.

Methods: We prospectively examined whether bowel motility, measured by self-reported frequency of bowel movements, and related factors (constipation, laxative use, water consumption, and dietary fiber intake) were associated with incidence of breast cancer among 28,586 postmenopausal women, ages 50 to 76 years, in the Vitamins and Lifestyle study. Cox proportional hazards models were used to estimate multivariate-adjusted relative risks (RR) and 95% confidence intervals (95% CI). From 2000 to 2005, 507 incident invasive breast cancers among the cohort were identified.

Results: Women with very frequent (≥3/d) bowel movements had a 46% decreased risk compared with 1/d women (RR, 0.54; 95% CI, 0.31-0.92), but the test for linear trend was not significant (Ptrend = 0.41). Constipation was nonsignificantly associated with increased risk (RR, 1.30 for ≥1/wk versus <1/y; 95% CI, 0.87-1.95). No statistically significant associations were observed for the other study exposures: 10-year chemical laxative use, 10-year use of fiber laxatives, water consumption, and dietary fiber intake.

Conclusion: This study adds limited support to the hypothesis that increased bowel motility lowers breast cancer risk. (Cancer Epidemiol Biomarkers Prev 2008;17(7):1746–50)
Successful Coordination and Execution of Nontherapeutic Studies in a Cooperative Group Setting: Lessons Learned from Children's Oncology Group Studies
Authors: Carter Andrea , Landier Wendy , Schad Amy , Moser Allison , Schaible Alexandra , Hanby Cara , Kurian Seira , Wong F. Lennie , Villaluna Doojduen , Bhatia Smita
Published: July 2008

The immense progress made in childhood cancer survival has been due to the systematic and efficient conduct of large multicenter therapeutic trials, using the infrastructure developed by national cooperative groups. These therapeutic trials have been successful, in part due to the high participation rates by the participating member institutions. However, participation in nontherapeutic trials in the cooperative group setting has lagged behind that of therapeutic trials for a variety of reasons, such as lack of institutional resources, leading to low priority given to such activities. The purpose of this report is to share some of the methods developed and successfully implemented by a coordinating center (City of Hope National Medical Center) to maximize institutional participation and patient enrollment and to standardize data collection and quality control, in order to ensure the successful execution of two large, extramurally funded, cooperative group nontherapeutic studies. To date, over 175 institutions have obtained regulatory approval for the protocols showcased here, accrual has been on target, and completeness and quality of the collected data have been excellent. The successful execution of these nontherapeutic studies shows the advantages of diverse study publicity techniques, detailed standardized operating procedures, and effective utilization of technological resources. (Cancer Epidemiol Biomarkers Prev 2008;17(7):1665–73)