bluuebunny/crossref_metadata_2025 huggingface dataset:
Design of shear reinforcement for thick plates using a strut-and-tie model
Authors: Marzouk H. , Rizk E. , Tiller R.
Published: March 2010

The strut-and-tie method is a rational approach to structural concrete design that results in a uniform and consistent design philosophy. A strut-and-tie model has been developed to model the punching-shear behaviour of thick concrete plates. This model provides a quick and simple approach to check the punching-shear behaviour. Thick concrete slabs (250–500 mm) without shear reinforcement can exhibit brittle shear failure under a central force and an unbalanced moment. Shear reinforcement has proven to be very effective in preventing such failures. The developed strut-and-tie model has also been used to evaluate the minimum shear reinforcement required to prevent brittle shear failure of two-way slabs in the vicinity of concentrated loads. The strut-and-tie model for symmetric punching consists of a “bottle-shaped” compressive zone in the upper section of the slab depth, leading to a “rectangular-stress” compressive zone in the lower section of the slab depth. Inclined shear cracking develops in the bottle-shaped zone prior to failure in the lower zone. Cracking in the bottle-shaped zone is related to the splitting tensile strength of concrete.
Design and seismic behaviour of taller eccentrically braced frames
Authors: Koboevic Sanda , David Simona Olivia
Published: March 2010

This paper describes a study of the seismic behaviour of taller eccentrically braced frames (EBFs). Chevron-type EBFs with shear-critical links are designed for 14-, 20-, and 25-storey buildings in Montreal and Vancouver. For each location the importance of different design criteria is discussed and an appropriate design sequence is proposed. It was found that ductility requirements did not control design. For Vancouver, buildings member selection was mostly influenced by the inelastic inter-storey drift requirements whereas for Montreal ensuring the global frame stability was critical. The seismic response of these frames to the sets of earthquake records calibrated to match design spectra is described. The seismic performance for Vancouver frames was found to be adequate, except that in the upper storeys the inelastic link deformations and shear forces exceeded values anticipated in design. For the Montreal structures, all global and local response indicators remained well below the design limits.
Generalized SDOF system for dynamic analysis of concrete rectangular liquid storage tanks: effect of tank parameters on response
Authors: Chen J. Z. , Kianoush M. R.
Published: March 2010

This paper presents the results of parametric studies on the seismic response of concrete rectangular liquid storage tanks using the generalized single-degree-of-freedom (SDOF) system. The effects of height of liquid and width of tank on the dynamic response of liquid storage tanks are investigated. The liquid level varies from the empty condition to a full tank. Also, instead of the commonly used ratio of width of tank to liquid height, Lx/HL, the ratio of width of tank to full height of the tank wall, Lx/Hw, is used as a characteristic parameter of tanks to study the effect of tank size on the dynamic response. The trends of added mass of liquid, effective height, and natural frequencies for different sizes of tanks are established. The values of the added mass of liquid due to impulsive hydrodynamic pressure and the effective height in the relationship with the ratios Lx/Hw and HL/Hw are determined and can be used in the seismic design of liquid storage tanks. Since the natural frequencies of liquid-containing structures are within a band of frequencies between that of a full tank and that of an empty tank, the recommended frequency to be used in the design of the tank wall is the frequency that causes the maximum dynamic response .
Influence of phosphorus, potassium, and copper on methane biofiltration performanceA paper submitted to the Journal of Environmental Engineering and Science.
Authors: Nikiema Josiane , Brzezinski Ryszard , Heitz Michèle
Published: March 2010

In addition to a carbon source, bacteria require for growth a variety of nutrients such as phosphorus, potassium, and several other micronutrients including copper. The study described in this paper was conducted with the aim of determining the influence of phosphorus, potassium, and copper on methane elimination in a biofilter. The study revealed that the particular phosphorus concentration leading to the greatest methane elimination capacity, which was 44.7 g m–3 h–1at a methane inlet load of 75 g m–3 h–1, was 3.1 g/L. The influence of the phosphorus concentration on the methane elimination capacities was also investigated for methane inlet loads of between 8 and 95 g m–3 h–1. The optimum range of the nitrogen–phosphorus mass ratios, determined during this study ranged from 0.5 to 2.5. It was established that, in comparison with phosphorus, potassium does not seem to be a determining element for the biological removal efficiency and does not significantly affect the microorganisms’ behaviour. However, a concentration of 0.076 g/L of potassium is recommended in the irrigation nutrient solution for an inlet load of 75 g m–3 h–1. The influence of the copper concentration was also studied by varying its concentration between the values of 0 and 0.006 g/L. The results have also shown that copper has a minor impact on the biofiltration of methane. This paper is the first report describing the influence of several nutrients in a biofilter. The knowledge provided by this study is necessary for the achievement of a biofilter indebted to methane control.
Vers une gestion durable et intégrée des eaux pluviales : Une étude de cas pour le Québec
Authors: Fuamba Musandji , Walliser Thomas , Daynou Mathurin , Rousselle Jean , Rivard Gilles
Published: March 2010

Pour inciter les professionnels québécois engagés dans la gestion durable et optimale des eaux pluviales à cibler des objectifs clairs, huit propositions d’action publique, de même qu’une démarche méthodologique sommaire pouvant aider à utiliser ces propositions de manière avisée et responsable, ont été suggérées dans l’article complémentaire. Le présent article traite d’une étude de cas où les huit propositions ont été appliquées dans un secteur en développement résidentiel d’une municipalité québécoise, en suivant la méthodologie proposée. L’objectif principal du présent article est de montrer la faisabilité d’utiliser de nouvelles pratiques de gestion optimale (PGO) des eaux pluviales au Québec. L’analyse économique sommaire, décrite seulement à titre indicatif dans cet article, montre que l’implantation de quelques PGO applicables au Québec sur la base d’objectifs précis de gestion intégrée et durable, est réalisable et même rentable. Une analyse technique poussée reste toutefois nécessaire pour identifier toutes les PGO susceptibles d’améliorer les conditions de drainage urbain au Québec, de même qu’une analyse économique approfondie reste indispensable pour préciser les véritables coûts liés à l’investissement dans les nouvelles techniques.
Flowing ability of self-consolidating concrete and its binder paste and mortar components incorporating rice husk ash
Authors: Safiuddin Md. , West J. S. , Soudki K. A.
Published: March 2010

This paper presents the flowing abilities of various self-consolidating concretes (SCCs) and their binder paste and mortar components. The binder pastes and mortars were formulated from the concrete mixtures and tested for flowing ability with respect to flow time and flow spread, respectively, at various dosages of high-range water reducing admixture (HRWRA). The concrete mixtures were prepared with different water (W) to binder (B) ratios and rice husk ash (RHA) contents. The flowing ability of the concretes was measured with regard to slump flow, orimet flow time and flow spread, and inverted slump cone flow time and flow spread. The test results reveal that the W:B ratio, RHA content, and HRWRA dosage significantly influenced the flowing abilities of the binder pastes, mortars, and concretes. In addition, the flowing ability of the SCCs was well correlated with the flowing abilities of their binder paste and mortar components, except for the mortars including RHA.
Investigation of bond between lap-spliced steel bar and self-compacting concrete: The role of silica fume
Authors: Karatas Mehmet , Turk Kazim , Ulucan Zulfu C.
Published: March 2010

In this study, normal concrete (NC) and four types of self-compacting concrete (SCC), in which cement was partially replaced by 5%, 10%, 15%, and 20% of silica fume (SF), were used to evaluate the effect of SF content on the bond strength of tension lap-spliced bars embedded in NC and SCC specimens. Therefore, 15 full-scale beam specimens (2000 × 300 × 200 mm3) were tested and 20 mm reinforcing bars were used with a 300-mm splice length as tension reinforcement. Each beam was designed with bars spliced in a constant moment region at midspan. It was found that the bond strength of the reinforcement embedded in SCC beams was higher than that of the reinforcement in NC beams, whilst the bond strength increased with increase in the replacement of cement by SF from 5% to 10%. Moreover, the beam specimens produced from SCC containing 5% SF had the highest normalized bond strength of 1.07 followed by SCC beams with 10% SF, 15% SF, NC beams, and 20% SF.
Driver tolerance of lateral accelerations on horizontal curves
Authors: Hildebrand Eric D. , Lewis Jonathan
Published: March 2010

There are many roadways where existing horizontal curves fail to meet minimum geometric design standards for financial or geographic reasons. Advisory speeds, typically set with a ball-bank indicator, are posted on these curves to ensure that drivers are not subjected to uncomfortable levels of lateral accelerations as they negotiate the curve. The threshold levels of lateral acceleration as estimated by ball-bank indicators vary considerably between jurisdictions with many still basing their guidelines on studies dating back to the 1930s and 1940s. This study investigated present day ball-bank indicator tolerance levels by analyzing actual driver behaviour on 30 curves posted with advisory speeds in New Brunswick. A unique method of data collection involving digital video analysis enabled the development of vehicle speed profiles approaching and throughout the curves. The results indicated that drivers tolerate higher levels of discomfort as they navigate curves than currently assumed. This finding justifies raising the ball-bank indicator threshold levels used for posting advisory speeds. Inconsistencies between actual posted advisory speeds, policy guidelines, and jurisdictional implementation have also been identified. Recommendations address both short and long-term goals of updating ball-bank indicator thresholds used for signing to levels that better represent driver behaviour. Longer-term recommendations address the development of uniform signing standards across Canada so that driver expectation will not be violated between jurisdictions.
A halogenated pseudopterane diterpene from the Bahamian octocoral Pseudopterogorgia acerosa
Authors: Kate Abhijeet S. , Richard Kelly , Ramanathan Balaji , Kerr Russell G.
Published: March 2010

Two new pseudopteranoid diterpenes have been isolated from the gorgonian coral Pseudopterogorgia acerosa and have been characterized by NMR and mass spectrometry. These include 15-chlorodeoxypseudopterolide (1), the first halogenated pseudopterane diterpene, and 11-epi-pseudopteranol (2), an epimer of the previously described 11-pseudopteranol. In addition, six known diterpenes were also isolated from this collection including deoxypseudopterolide (3), pseudopteradiene (4), acerosolide (5), pseudopterolide-methanol adduct (6), 11-pseudopteranol (7), and isogorgiacerodiol (8). The cytotoxicity of these eight compounds towards three cancer cell lines (HeLa, PC-3, and HCT116) was assessed and the chlorinated pseudopteranoid 1 was found to have modest but selective activity against HCT116 (IC50 2.7 µmol/L), whereas its nonchlorinated derivative 3 was inactive. This indicates that the halo functionality can modify the cytotoxic activity of pseudopteranoids and potentially other classes of deterpenes.
Enantioselective fluorescent sensors for chiral carboxylates based on BINOL — Synthesis and chiral recognition
Authors: Xu Kuo-xi , Wang Yu-xia , Jiao Shu-yan , Zhao Jin , Wang Chao-jie
Published: March 2010

The four novel derivatives of 1,1′-bi-2-naphthol (BINOL) have been prepared, and the structures of these compounds have been characterized by IR, MS, 1H and 13C NMR spectroscopy, and elemental analysis. The enantioselective recognition of these receptors has been studied by fluorescence titration and 1H NMR spectroscopy. The receptors exhibited different chiral-recognition abilities towards some enantiomers of chiral materials and formed 1:1 complexes between host and guest. The receptors exhibit excellent enantioselective fluorescent-recognition ability towards the amino acid derivatives.
Theoretical study of H bonds of HArF and HF with isoelectronic systems N2, CO, and BF
Authors: Li An Yong , Cao Li Juan , Ji Hong Bo
Published: March 2010

The H bonds of HArF and HF with N2, CO, and BF were studied at the MP2(full)/6-311++G(2d, 2p) level. The results show that only the complexes WY···HArF (WY = N2, OC) and WY···HF (WY = N2, OC, FB) are stable, the H-bonding WY···HArF leads to contraction of the HAr bond with a concomitant frequency blue shift, but the H-bonding WY···HF causes the HF bond to elongate with a frequency red shift. A quantity P is defined to measure polarization of the HX bond; the H bonding causes the P value of the HX bond (X = Ar, F) to increase. The HX bond length change and frequency shift in the H-bonding WY···HArF and WY···HF are mainly caused by intermolecular hyperconjugation, n(Y) → σ*(HX) (X = Ar, F), where electrostatic interaction has only a small contribution. In HArF, the strong intramolecular hyperconjugation, n(F) → σ*(HAr), can adjust electron density on σ*(HAr); upon formation of H bonding, the HAr stretching frequency blue shift is caused by a decrease of intramolecular hyperconjugation and an increase of the s character of the Ar hybrid in the HAr bond, induced by the intermolecular hyperconjugation. In the H bonds of HF without intramolecular hyperconjugation, the intermolecular hyperconjugation, n(Y) → σ*(HF), leads to a red shift of the HF bond, although there is also large rehybridization.
Catalytic hypervalent iodine oxidation of alcohols to the corresponding carbonyl compounds usingN-hydroxyphthalimide (NHPI) andm-chloroperbenzoic acid
Authors: Zhu Chenjie , Ji Lei , Zhang Qian , Wei Yunyang
Published: March 2010

An efficient, facile, and mild oxidation of alcohols to the corresponding carbonyl compounds with m-chloroperbenzoic acid (mCPBA) and N-hydroxyphthalimide (NHPI) in the presence of a catalytic amount of iodobenzene was reported. The oxidation proceeded in mixed solvent at room temperature to afford carbonyl compounds in excellent yields. A possible mechanism for the oxidation was proposed.
Transcriptional regulation of histidine biosynthesis genes in Corynebacterium glutamicum
Authors: Jung Samil , Chun Jae-Yeon , Yim Sei-Heun , Lee Soo-Suk , Cheon Choong-Il , Song Eunsook , Lee Myeong-Sok
Published: March 2010

Corynebacterium glutamicum , a gram-positive bacterium, has been widely used for industrial amino acid production. Corynebacterium glutamicum his genes are located and transcribed in two unlinked loci, hisEG and hisDCB–orf1–orf2–hisHA–impA–hisFI. The latter his operon starts the transcription at the C residue localized 196 bp upstream of the hisD ATG start codon. Our computer-based sequence analysis showed that the region corresponding to the untranslated 5′ end of the transcript, named the hisD leader region, displays the typical features of the T-box transcriptional attenuation mechanism. Therefore, expression of the cat reporter gene under the control of the wild-type or mutated hisD leader regions was tested in multi-copy (pProm and pTer series) and in single-copy (pInt series) systems under conditions of sufficient or limited histidine. Our mutational studies led to the conclusion that the CAU histidine specifier and 5′-UGGA-3′ sequence in the hisD leader region are required for the hisDCB–orf1–orf2–hisHA–impA–hisFI gene regulation. The cat gene expression from the wild-type leader region was negatively regulated by histidine. However, the cat gene expression from mutated leader regions was irresponsive to the level of histidine in the growth medium. Taken together, we propose that a T-box mediated attenuation mechanism is responsible for the gene expression of the hisDCB–orf1–orf2–hisHA–impA–hisFI operon in C. glutamicum.
Characterization and expression of a novel holotype insecticidal crystal protein gene from nativeBacillus thuringiensisBM59-2
Authors: Zheng Aiping , Zhu Jun , Wang Lingxia , Li Shuangcheng , Deng Qiming , Wang Shiquan , Tan Furong , Yu Xiumei , Guan Peng , Liang Hongxia , Li Ping
Published: March 2010

We characterized a novel holotype cry gene (cry52Ba1) harbored in a Bacillus thuringiensis isolate BM59-2 native to China that expresses a spherical crystal protein of about 80 kDa. In this study, the full length of the cry52Ba1 gene was cloned from this strain. Sequence analysis of the gene was also performed. Furthermore, cry52Ba1 was expressed in Escherichia coli BL21(DE)pLysS, and the resulting insecticidal activity showed that the Cry52Ba1 protein exhibited high larvicidal activity against Aedes aegypti (Diptera), with a lethal concentration 50 of 1.526 µg/mL (95% confidence: 0.740–3.499 µg/mL).
Sequences required for transcription termination at the intrinsic λtIterminator
Authors: Martínez-Trujillo Miguel , Sánchez-Trujillo Alejandra , Ceja Víctor , Ávila-Moreno Federico , Bermúdez-Cruz Rosa María , Court Donald , Montañez Cecilia
Published: March 2010

The λtI terminator is located approximately 280 bp beyond the λint gene, and it has a typical structure of an intrinsic terminator. To identify sequences required for λtI transcription termination a set of deletion mutants were generated, either from the 5′ or the 3′ end onto the λtI region. The termination efficiency was determined by measuring galactokinase (galK) levels by Northern blot assays and by in vitro transcription termination. The importance of the uridines and the stability of the stem structure in the termination were demonstrated. The nontranscribed DNA beyond the 3′ end also affects termination. Additionally, sequences upstream have a small effect on transcription termination. The in vivo RNA termination sites at λtI were determined by S1 mapping and were located at 8 different positions. Processing of transcripts from the 3′ end confirmed the importance of the hairpin stem in protection against exonuclease.
Flickering calcium microdomains signal turning of migrating cellsThis article is one of a selection of papers published in this special issue on Calcium Signaling.
Authors: Wei Chaoliang , Wang Xianhua , Chen Min , Ouyang Kunfu , Zheng Ming , Cheng Heping
Published: March 2010

It has been well-established that polarized migrating cells exhibit a stable and transient gradient of intracellular calcium concentration ([Ca2+]i), increasing from front-to-rear, that is thought to be responsible for rear retraction. The paradox that arises is how calcium at the front of a cell catalyzes critical high-threshold calcium-dependent processes during cell migration and particularly in decision-making for a cell to turn. In this brief review, we discuss the recent discovery of flickering high-[Ca2+]i microdomains (“calcium flickers”) at the front of migrating fibroblasts and their common role in transducing local membrane mechanical stress (via TRPM7, a stretch-activated calcium-permeating transient receptor potential channel) and chemoattractant-elicited signals (via type 2 inositol 1,4,5-trisphosphate receptor in the endoplasmic reticulum). Furthermore, we present a new model for patterned calcium flicker activity as the mechanism for steering the turning of a migrating cell.
Spatial distribution and habitat selection of Barrow’s and Common goldeneyes wintering in the St. Lawrence marine system
Authors: Ouellet Jean-François , Guillemette M. , Robert M.
Published: March 2010

Our study addresses winter spatial distribution of Barrow’s Goldeneyes ( Bucephala islandica (Gmelin, 1789)) and Common Goldeneyes ( Bucephala clangula (L., 1758)) at the scale of the St. Lawrence marine system (estuary and northwestern gulf), eastern Canada. Our objectives were (i) to identify and compare the physical factors that control their distributions, (ii) to quantify the level of sympatry between the two species, and (iii) to compare their distribution patterns. We analyzed large-scale synoptic views of winter distribution of both goldeneye species obtained through helicopter-borne surveys. Habitat description was obtained through spatial analyses and remote sensing. Both species showed strong preference for the tidal zone and river mouths. A multiscale analysis showed a decreasing level of sympatry as spatial resolution was refined. The distribution of the Barrow’s Goldeneye was more clustered compared with that of the Common Goldeneye, and Barrow’s Goldeneye was repeatedly observed in the same few areas. A use-availability analysis identified the northern coast of the St. Lawrence estuary as the main wintering ground for Barrow’s Goldeneye in eastern North America.
Stable isotope analysis and satellite tracking reveal interspecific resource partitioning of nonbreeding albatrosses off Alaska
Authors: Suryan Robert M. , Fischer Karen N.
Published: March 2010

Albatrosses (Diomedeidae) are the most threatened family of birds globally. The three North Pacific species ( Phoebastria Reichenbach, 1853) are listed as either endangered or vulnerable, with the population of Short-tailed Albatross ( Phoebastria albatrus (Pallas, 1769)) less than 1% of its historical size. All North Pacific albatross species do not currently breed sympatrically, yet they do co-occur at-sea during the nonbreeding season. We incorporated stable isotope analysis with the first simultaneous satellite-tracking study of all three North Pacific albatross species while sympatric on summer (nonbreeding season) foraging grounds off Alaska. Carbon isotope ratios and tracking data identify differences in primary foraging domains of continental shelf and slope waters for Short-tailed Albatrosses and Black-footed Albatrosses ( Phoebastria nigripes (Audubon, 1839)) versus oceanic waters for Laysan Albatrosses ( Phoebastria immutabilis (Rothschild, 1893)). Short-tailed and Black-footed albatrosses also fed at higher trophic levels than Laysan Albatrosses. The relative trophic position of Black-footed and Laysan albatrosses, however, appears to differ between nonbreeding and breeding seasons. Spatial segregation also occurred at a broader geographic scale, with Short-tailed Albatrosses ranging more north into the Bering Sea than Black-footed Albatrosses, which ranged more to the southeast, and Laysan Albatrosses more to the southwest. Differences in carbon isotope ratios among North Pacific albatross species during the nonbreeding season likely reflect the relative proportion of neritic (more carbon enriched) versus oceanic (carbon depleted) derived nutrients, and possible differential use of fishery discards, rather than latitudinal differences in distribution.
PERTURBATIVE DEFORMATIONS OF CONFORMAL FIELD THEORIES REVISITED
Authors: KRIZ IGOR
Published: March 2010

The purpose of this paper is to revisit the theory of perturbative deformations of conformal field theory from a mathematically rigorous, purely worldsheet point of view. We specifically include the case of N = (2,2) conformal field theories. From this point of view, we find certain surprising obstructions, which appear to indicate that contrary to previous findings, not all deformations along marginal fields exist perturbatively. This includes the case of deformation of the Gepner model of the Fermat quintic along certain cc fields. In other cases, including Gepner models of K3-surfaces and the free field theory, our results coincides with known predictions. We give partial interpretation of our results via renormalization and mirror symmetry.
ON THE EXISTENCE OF THE DYNAMICS FOR ANHARMONIC QUANTUM OSCILLATOR SYSTEMS
Authors: NACHTERGAELE BRUNO , SCHLEIN BENJAMIN , SIMS ROBERT , STARR SHANNON , ZAGREBNOV VALENTIN
Published: March 2010

We construct a W*-dynamical system describing the dynamics of a class of anharmonic quantum oscillator lattice systems in the thermodynamic limit. Our approach is based on recently proved Lieb–Robinson bounds for such systems on finite lattices [19].
The Behavioral Response to Personalized Genetic Information: Will Genetic Risk Profiles Motivate Individuals and Families to Choose More Healthful Behaviors?
Authors: McBride Colleen M. , Koehly Laura M. , Sanderson Saskia C. , Kaphingst Kimberly A.
Published: March 2010

This report describes the use of information emerging from genetic discovery to motivate risk-reducing health behaviors. Most research to date has evaluated the effects of information related to rare genetic variants on screening behaviors, in which genetic risk feedback has been associated consistently with improved screening adherence. The limited research with common genetic variants suggests that genetic information, when based on single-gene variants with low-risk probabilities, has little impact on behavior. The effect on behavioral outcomes of more realistic testing scenarios in which genetic risk is based on numerous genetic variants is largely unexplored. Little attention has been directed to matching genetic information to the literacy levels of target audiences. Another promising area for research is consideration of using genetic information to identify risk shared within kinship networks and to expand the influence of behavior change beyond the individual.
How Experience Gets Under the Skin to Create Gradients in Developmental Health
Authors: Hertzman Clyde , Boyce Tom
Published: March 2010

Social environments and experiences get under the skin early in life in ways that affect the course of human development. Because most factors associated with early child development are a function of socio-economic status, differences in early child development form a socio-economic gradient. We are now learning how, when, and by what means early experiences influence key biological systems over the long term to produce gradients: a process known as biological embedding. Opportunities for biological embedding are tethered closely to sensitive periods in the development of neural circuitry. Epigenetic regulation is the best example of operating principles relevant to biological embedding. We are now in a position to ask how early childhood environments work together with genetic variation and epigenetic regulation to generate socially partitioned developmental trajectories with impact on health across the life course.
Simulation Modeling of Health Care Policy
Authors: Glied Sherry , Tilipman Nicholas
Published: March 2010

Simulation modeling of health reform is a standard part of policy development and, in the United States, a required element in enacting health reform legislation. Modelers use three types of basic structures to build models of the health system: microsimulation, individual choice, and cell-based. These frameworks are filled in with data on baseline characteristics of the system and parameters describing individual behavior. Available data on baseline characteristics are imprecise, and estimates of key empirical parameters vary widely. A comparison of estimated and realized consequences of several health reform proposals suggests that models provided reasonably accurate estimates, with confidence bounds of ∼30%.
Recent Advances in Public Health Systems Research in the United States
Authors: Van Wave, Timothy W. , Scutchfield F. Douglas , Honoré Peggy A.
Published: March 2010

Recognizing the public's health is the outcome of dynamic, adaptive, and complex systems of agencies; infrastructure, relationships, and interactions that dictate how to improve health outcomes; and reducing health risks in a population is based on systems thinking and evidence. New methods such as network analysis and public health practice–based research networks demonstrate the potential for new insight to our understanding of how systems and infrastructure influence population health. We examine advances in public health systems research since 1988 and discuss the relevance of this type of research to public health practice. We assess the current infrastructure for conducting public health systems research, suggest how the research infrastructure can be improved, and conclude with a discussion of how health reform in the United States will require research focused on understanding the adaptive complexity inherent in public health and health care systems and strengthening the systems research infrastructure.
Methods for Investigating Gene-Environment Interactions in Candidate Pathway and Genome-Wide Association Studies
Authors: Thomas Duncan
Published: March 2010

Despite the considerable enthusiasm about the yield of novel and replicated discoveries of genetic associations from the new generation of genome-wide association studies (GWAS), the proportion of the heritability of most complex diseases that have been studied to date remains small. Some of this “dark matter” could be due to gene-environment (G × E) interactions or more complex pathways involving multiple genes and exposures. We review the basic epidemiologic study design and statistical analysis approaches to studying G × E interactions individually and then consider more comprehensive approaches to studying entire pathways or GWAS data. In addition to the usual issues in genetic association studies, particular care is needed in exposure assessment, and very large sample sizes are required. Although hypothesis-driven, pathway-based and agnostic GWA study approaches are generally viewed as opposite poles, we suggest that the two can be usefully married using hierarchical modeling strategies that exploit external pathway knowledge in mining genome-wide data.
The Health and Health Care of Lesbian, Gay, and Bisexual Adolescents
Authors: Coker Tumaini R. , Austin S. Bryn , Schuster Mark A.
Published: March 2010

Adolescents face a variety of challenges in their transition to adulthood; lesbian, gay, and bisexual adolescents face these typical challenges as well as additional challenges that are related to the social stigma of their sexual orientation. For some lesbian, gay, and bisexual adolescents, this stigma may induce psychosocial stress, leading to increased health risk behaviors and poorer health outcomes. In this article, we review data on the health and health care of LGB adolescents. We examine health indicators and health risks for LGB youth, including substance use, eating disorders, suicidality, risky sexual behaviors, violence exposure and victimization, and homelessness. We also examine health care provision and utilization for LGB youth. Lastly, we discuss ways in which researchers and clinicians can improve LGB adolescent health and health care.
Nutrigenetics/Nutrigenomics
Authors: Simopoulos Artemis P.
Published: March 2010

All diseases have a genetic predisposition. Genome-wide association studies (GWASs) by large international consortia are discovering genetic variants that contribute to complex diseases. However, nutrient information is missing, which is essential for the development of dietary advice for prevention and management of disease. Nutrigenetics/nutrigenomics studies provide data on mechanisms of nutrient and gene interactions in health and disease needed for personalized nutrition. A process will be needed to define when gene-nutrient-disease associations are ready to be evaluated as potential tools to improve public health.
Two Decades of Declining Cancer Mortality: Progress with Disparity
Authors: Byers Tim
Published: March 2010

The close of the twentieth century brought historic changes in cancer risk factors, early detection, and treatment. As a consequence, we have seen two decades of steadily declining risk of death from cancer in the United States. The reasons for declining cancer mortality rates are largely known: reduced tobacco use, the adoption of cancer early-detection methods, and better cancer therapeutics. Despite this progress, disparities in cancer mortality persist across different groups defined by race and social class. Because all the factors that account for declining cancer trends are influenced strongly by social class, and because of large social class disparities in cancer risk factors, there will likely be a widening gap in cancer mortality among those in lower socioeconomic groups in the future. This article reviews the trends in risk factors for cancer mortality and discusses the persistent problem of disparities by race and social class.
Enhanced student experience: an analysis of subjective evaluation and objective learning success after the transformation of a pharmaceutical physiology course
Authors: Zimmermann Martina , Eckert Gunter P.
Published: March 2010

In the present article, the reorientation of a fourth-semester physiology course for pharmacy students is described. The motivation for the introduction of changes was to prepare the students to not only assimilate facts but to learn and understand how to integrate and apply them. The article considers how this reorganization was received by the students in both subjective and objective terms. Specifically, we investigate whether our changes resulted in both an enhanced learning experience and improved learning success. The following changes were introduced to the course: first, we integrated either experimental, computer-based teaching modules or case studies in five of the eight course units to give the students the opportunity to gain more hands-on experience; second, we organized regular meetings to enhance communication among the course tutors; and finally, we increased the pass mark for the entrance exam to the course from 50% to 60%. Student opinion was evaluated by means of a questionnaire that was distributed at the end of each course semester throughout the three-semester evaluation period (summer 2008, winter 2008/2009, and summer 2009). The students gave convincing positive feedback concerning the efficacy of the changes in both quantitative and qualitative terms. Moreover, their learning success improved significantly in objective terms as evidenced by enhanced final and State exam performance.
Progressive adaptation of hepatic ketogenesis in mice fed a high-fat diet
Authors: Sunny Nishanth E. , Satapati Santhosh , Fu Xiaorong , He TianTeng , Mehdibeigi Roshi , Spring-Robinson Chandra , Duarte Joao , Potthoff Matthew J. , Browning Jeffrey D. , Burgess Shawn C.
Published: March 2010

Hepatic ketogenesis provides a vital systemic fuel during fasting because ketone bodies are oxidized by most peripheral tissues and, unlike glucose, can be synthesized from fatty acids via mitochondrial β-oxidation. Since dysfunctional mitochondrial fat oxidation may be a cofactor in insulin-resistant tissue, the objective of this study was to determine whether diet-induced insulin resistance in mice results in impaired in vivo hepatic fat oxidation secondary to defects in ketogenesis. Ketone turnover (μmol/min) in the conscious and unrestrained mouse was responsive to induction and diminution of hepatic fat oxidation, as indicated by an eightfold rise during the fed (0.50+/−0.1)-to-fasted (3.8+/−0.2) transition and a dramatic blunting of fasting ketone turnover in PPARα−/−mice (1.0+/−0.1). C57BL/6 mice made obese and insulin resistant by high-fat feeding for 8 wk had normal expression of genes that regulate hepatic fat oxidation, whereas 16 wk on the diet induced expression of these genes and stimulated the function of hepatic mitochondrial fat oxidation, as indicated by a 40% induction of fasting ketogenesis and a twofold rise in short-chain acylcarnitines. Together, these findings indicate a progressive adaptation of hepatic ketogenesis during high-fat feeding, resulting in increased hepatic fat oxidation after 16 wk of a high-fat diet. We conclude that mitochondrial fat oxidation is stimulated rather than impaired during the initiation of hepatic insulin resistance in mice.
Growth hormone rescues hippocampal synaptic function after sleep deprivation
Authors: Kim Eunyoung , Grover Lawrence M. , Bertolotti Don , Green Todd L.
Published: March 2010

Sleep is required for, and sleep loss impairs, normal hippocampal synaptic N-methyl-d-aspartate (NMDA) glutamate receptor function and expression, hippocampal NMDA receptor-dependent synaptic plasticity, and hippocampal-dependent memory function. Although sleep is essential, the signals linking sleep to hippocampal function are not known. One potential signal is growth hormone. Growth hormone is released during sleep, and its release is suppressed during sleep deprivation. If growth hormone links sleep to hippocampal function, then restoration of growth hormone during sleep deprivation should prevent adverse consequences of sleep loss. To test this hypothesis, we examined rat hippocampus for spontaneous excitatory synaptic currents in CA1 pyramidal neurons, long-term potentiation in area CA1, and NMDA receptor subunit proteins in synaptic membranes. Three days of sleep deprivation caused a significant reduction in NMDA receptor-mediated synaptic currents compared with control treatments. When rats were injected with growth hormone once per day during sleep deprivation, the loss of NMDA receptor-mediated synaptic currents was prevented. Growth hormone injections also prevented the impairment of long-term potentiation that normally follows sleep deprivation. In addition, sleep deprivation led to a selective loss of NMDA receptor 2B (NR2B) from hippocampal synaptic membranes, but normal NR2B expression was restored by growth hormone injection. Our results identify growth hormone as a critical mediator linking sleep to normal synaptic function of the hippocampus.
Multiscale model for the assessment of autonomic dysfunction in human endotoxemia
Authors: Foteinou Panagiota T. , Calvano Steve E. , Lowry Stephen F. , Androulakis Ioannis P.
Published: March 2010

Severe injury and infection are associated with autonomic dysfunction. The realization that a dysregulation in autonomic function may predispose a host to excessive inflammatory processes has renewed interest in understanding the role of central nervous system (CNS) in modulating systemic inflammatory processes. Assessment of heart rate variability (HRV) has been used to evaluate systemic abnormalities and as a predictor of the severity of illness. Dissecting the relevance of neuroimmunomodulation in controlling inflammatory processes requires an understanding of the multiscale interplay between CNS and the immune response. A vital enabler in that respect is the development of a systems-based approach that integrates data across multiple scales, and models the emerging host response as the outcome of interactions of critical modules. Thus, a multiscale model of human endotoxemia, as a prototype model of systemic inflammation in humans, is proposed that integrates processes across the host from the cellular to the systemic host response level. At the cellular level interacting components are associated with elementary signaling pathways that propagate extracellular signals to the transcriptional response level. Further, essential modules associated with the neuroendocrine immune crosstalk are considered. Finally, at the systemic level, phenotypic expressions such as HRV are incorporated to assess systemic decomplexification indicative of the severity of the host response. Thus, the proposed work intends to associate acquired endocrine dysfunction with diminished HRV as a critical enabler for clarifying how cellular inflammatory processes and neural-based pathways mediate the links between patterns of autonomic control (HRV) and clinical outcomes.
A High‐Yield Synthesis of Chalcopyrite CuInS2 Nanoparticles with Exceptional Size Control
Authors: Sun Chivin , Gardner Joseph S. , Shurdha Endrit , Margulieux Kelsey R. , Westover Richard D. , Lau Lisa , Long Gary , Bajracharya Cyril , Wang Chongmin , Thurber Aaron , Punnoose Alex , Rodriguez Rene G. , Pak Joshua J.
Published: March 2010

We report high‐yield and efficient size‐controlled syntheses of Chalcopyrite CuInS2 nanoparticles by decomposing molecular single source precursors (SSPs) via microwave irradiation in the presence of 1,2‐ethanedithiol at reaction temperatures as low as 100°C and times as short as 30 minutes. The nanoparticles sizes were 1.8 nm to 10.8 nm as reaction temperatures were varied from 100°C to 200°C with the bandgaps from 2.71 eV to 1.28 eV with good size control and high yields (64%–95%). The resulting nanoparticles were analyzed by XRD, UV‐Vis, ICP‐OES, XPS, SEM, EDS, and HRTEM. Titration studies by 1H NMR using SSP 1 with 1,2‐ethanedithiol and benzyl mercaptan were conducted to elucidate the formation of Chalcopyrite CuInS2 nanoparticles.
Trends in Mean Annual Minimum and Maximum Near Surface Temperature in Nairobi City, Kenya
Authors: Makokha George Lukoye , Shisanya Chris A.
Published: March 2010

This paper examines the long‐term urban modification of mean annual conditions of near surface temperature in Nairobi City. Data from four weather stations situated in Nairobi were collected from the Kenya Meteorological Department for the period from 1966 to 1999 inclusive. The data included mean annual maximum and minimum temperatures, and was first subjected to homogeneity test before analysis. Both linear regression and Mann‐Kendall rank test were used to discern the mean annual trends. Results show that the change of temperature over the thirty‐four years study period is higher for minimum temperature than maximum temperature. The warming trends began earlier and are more significant at the urban stations than is the case at the sub‐urban stations, an indication of the spread of urbanisation from the built‐up Central Business District (CBD) to the suburbs. The established significant warming trends in minimum temperature, which are likely to reach higher proportions in future, pose serious challenges on climate and urban planning of the city. In particular the effect of increased minimum temperature on human physiological comfort, building and urban design, wind circulation and air pollution needs to be incorporated in future urban planning programmes of the city.
Anti-Inflammatory Effects of Licorice and Roasted Licorice Extracts on TPA-Induced Acute Inflammation and Collagen-Induced Arthritis in Mice
Authors: Kim Ki Rim , Jeong Chan-Kwon , Park Kwang-Kyun , Choi Jong-Hoon , Park Jung Han Yoon , Lim Soon Sung , Chung Won-Yoon
Published: March 2010

The anti-inflammatory activity of licorice (LE) and roated licorice (rLE) extracts determined in the murine phorbol ester-induced acute inflammation model and collagen-induced arthritis (CIA) model of human rheumatoid arthritis. rLE possessed greater activity than LE in inhibiting phorbol ester-induced ear edema. Oral administration of LE or rLE reduced clinical arthritis score, paw swelling, and histopathological changes in a murine CIA. LE and rLE decreased the levels of proinflammatory cytokines in serum and matrix metalloproteinase-3 expression in the joints. Cell proliferation and cytokine secretion in response to type II collagen or lipopolysaccharide stimulation were suppressed in spleen cells from LE or rLE-treated CIA mice. Furthermore, LE and rLE treatment prevented oxidative damages in liver and kidney tissues of CIA mice. Taken together, LE and rLE have benefits in protecting against both acute inflammation and chronic inflammatory conditions including rheumatoid arthritis. rLE may inhibit the acute inflammation more potently than LE.
A Rare Case of Squamous Cell Carcinoma of the Bladder Presenting as a Metastatic Right Ventricular Mass
Authors: Bonsall Joanna M. , Hughes Rhome , Mosunjac Mario , Harrison David , Samady Habib
Published: March 2010

A 74-year-old woman presented with bilateral lower extremity swelling, worsening dyspnea on exertion, and mild hemoptysis. An echocardiogram at time of admission showed a mass in the right ventricle. The pathology of a sample obtained via transvenous biopsy was consistent with squamous cell carcinoma; no primary source could initially be identified. Severe thrombocytopenia, likely consumptive, precluded surgical intervention, so the patient underwent palliative radiation. Unfortunately, she developed fatal respiratory failure. Upon autopsy, the bladder was found to contain polyps of invasive squamous cell carcinoma, similar in morphology to the tumor mass in the heart. Her lungs contained multiple tumor emboli at different stages, which was likely the final cause of her death. Squamous cell carcinoma metastases to the endocardium are extremely rare and without defined treatment. Surgery can improve prognosis in those with primary tumors that are benign or without metastases. In those with symptomatic metastatic tumors, palliative debulking can done although generally will not improve prognosis. It is currently unknown whether radiation improves survival. In this case, irradiation did destroy a portion of the tumor as the final pathology showed extensive necrosis of the tumor; unfortunately, it did not change her symptoms and did not change the final outcome.
Forkhead Box F1 Regulates Tumor-Promoting Properties of Cancer-Associated Fibroblasts in Lung Cancer
Authors: Saito Roy-Akira , Micke Patrick , Paulsson Janna , Augsten Martin , Peña Cristina , Jönsson Per , Botling Johan , Edlund Karolina , Johansson Leif , Carlsson Peter , Jirström Karin , Miyazono Kohei , Östman Arne
Published: March 2010

Cancer-associated fibroblasts (CAF) attract increasing attention as potential cancer drug targets due to their ability to stimulate, for example, tumor growth, invasion, angiogenesis, and metastasis. However, the molecular mechanisms causing the tumor-promoting properties of CAFs remain poorly understood. Forkhead box F1 (FoxF1) is a mesenchymal target of hedgehog signaling, known to regulate mesenchymal-epithelial interactions during lung development. Studies with FoxF1 gain- and loss-of-function fibroblasts revealed that FoxF1 regulates the contractility of fibroblasts, their production of hepatocyte growth factor and fibroblast growth factor-2, and their stimulation of lung cancer cell migration. FoxF1 status of fibroblasts was also shown to control the ability of fibroblasts to stimulate xenografted tumor growth. FoxF1 was expressed in CAFs of human lung cancer and associated with activation of hedgehog signaling. These observations suggest that hedgehog-dependent FoxF1 is a clinically relevant lung CAF-inducing factor, and support experimentally the general concept that CAF properties can be induced by activation of developmentally important transcription factors. Cancer Res; 70(7); 2644–54