bluuebunny/crossref_metadata_2025 huggingface dataset:
A new genetic linkage map of tomato based on aSolanum lycopersicum ×S. pimpinellifoliumRIL population displaying locations of candidate pathogen response genes
Authors: Ashrafi Hamid , Kinkade Matthew , Foolad Majid R.
Published: November 2009

The narrow genetic base of the cultivated tomato, Solanum lycopersicum L., necessitates introgression of new variation from related species. Wild tomato species represent a rich source of useful genes and traits. Exploitation of genetic variation within wild species can be facilitated by the use of molecular markers and genetic maps. Recently we identified an accession (LA2093) within the red-fruited wild tomato species Solanum pimpinellifolium L. with exceptionally desirable characteristics, including disease resistance, abiotic stress tolerance, and high fruit lycopene content. To facilitate genetic characterization of such traits and their exploitation in tomato crop improvement, we developed a new recombinant inbred line (RIL) population from a cross between LA2093 and an advanced tomato breeding line (NCEBR-1). Furthermore, we constructed a medium-density molecular linkage map of this population using 294 polymorphic markers, including standard RFLPs, EST sequences (used as RFLP probes), CAPS, and SSRs. The map spanned 1091 cM of the tomato genome with an average marker spacing of 3.7 cM. A majority of the EST sequences, which were mainly chosen based on the putative role of their unigenes in disease resistance, defense-related response, or fruit quality, were mapped onto the tomato chromosomes for the first time. Co-localizations of relevant EST sequences with known disease resistance genes in tomato were also examined. This map will facilitate identification, genetic exploitation, and positional cloning of important genes or quantitative trait loci in LA2093. It also will allow the elucidation of the molecular mechanism(s) underlying important traits segregating in the RIL population. The map may further facilitate characterization and exploitation of genetic variation in other S. pimpinellifolium accessions as well as in modern cultivars of tomato.
Identifying commercially relevantEchinaceaspecies by AFLP molecular markers
Authors: Russi Luigi , Moretti Chiaraluce , Raggi Lorenzo , Albertini Emidio , Falistocco Egizia
Published: November 2009

The rising interest in medicinal plants has brought several species of the genus Echinacea to the attention of many scientists. Echinacea angustifolia , E. pallida , and E. purpurea are the most important for their immunological properties, well known and widely used by the native Americans. The three species are easily distinguishable on the basis of their morphological characteristics, but it would be difficult, if not impossible, to distinguish them in commercial preparations of ground, dry plant parts of E. purpurea (the most valuable species for chemotherapeutic properties) mixed with the other two species. Species-specific molecular markers could be useful to address this issue. In the present work, using fresh material collected from cultivated Echinacea spp., AFLP analysis was used to discriminate the three species and to detect species-specific DNA fragments. By using 14 primer combinations it was possible to detect a total of 994 fragments, of which 565 were polymorphic. Overall, 89 fragments were unique to E. purpurea, 32 to E. angustifolia, and 26 to E. pallida. E+CAC/M+AAT or E+CAC/M+AGC alone provided 13, 9, and 4 or 7, 5, and 5 specific fragments for E. purpurea, E. angustifolia, and E. pallida, respectively. A validation trial to confirm the results was carried out on bulked samples of 23 accessions covering most of the genetic diversity of the three species. The results are discussed in terms of practical applications in the field of popular medicine, detecting frauds, and implications for the genus Echinacea.
Modifiers ofPrat, a de novo purine synthesis gene, inDrosophila melanogaster
Authors: Hackett Joanne M. , Clark Denise V.
Published: November 2009

Drosophila melanogaster was used to identify genes with a potential role in genetic regulation of purine biosynthesis. In this study we examine two dominant genetic modifiers of the essential gene Prat, which encodes amidophosphoribosyltransferase (EC 2.4.2.14). We found that Mod(Prat:bw)3-1 enhances Prat expression only in female heads, whereas Mod(Prat:bw)3-5 suppresses Prat in all stages and tissues examined for both sexes. For Mod-3-5, gene expression microarrays were used to identify other genes that are affected by the modifier. Three mapping approaches were used to localize these modifiers. Deficiency and meiotic mapping showed that the complex lethal complementation group previously associated with Mod-3-1 and Mod-3-5 is actually due to shared second-site lethal mutations. Using male recombination mapping, Mod-3-1 was localized to a 21 kilobase region containing nine genes, and Mod-3-5 was localized to a 53 kilobase region containing eight genes.
mTOR function in skeletal muscle: a focal point for overnutrition and exercise
Authors: Rivas Donato A. , Lessard Sarah J. , Coffey Vernon G.
Published: November 2009

The mammalian target of rapamycin (mTOR) is a highly conserved atypical serine–threonine kinase that controls numerous functions essential for cell homeostasis and adaptation in mammalian cells via 2 distinct protein complex formations. Moreover, mTOR is a key regulatory protein in the insulin signalling cascade and has also been characterized as an insulin-independent nutrient sensor that may represent a critical mediator in obesity-related impairments of insulin action in skeletal muscle. Exercise characterizes a remedial modality that enhances mTOR activity and subsequently promotes beneficial metabolic adaptation in skeletal muscle. Thus, the metabolic effects of nutrients and exercise have the capacity to converge at the mTOR protein complexes and subsequently modify mTOR function. Accordingly, the aim of the present review is to highlight the role of mTOR in the regulation of insulin action in response to overnutrition and the capacity for exercise to enhance mTOR activity in skeletal muscle.
Women with type 2 diabetes perceive harder effort during exercise than nondiabetic women
Authors: Huebschmann Amy G. , Reis Erin N. , Emsermann Caroline , Dickinson L. Miriam , Reusch Jane E.B. , Bauer Timothy A. , Regensteiner Judith G.
Published: November 2009

Regular exercise is a cornerstone of diabetes treatment; however, people with type 2 diabetes (T2D) are commonly sedentary. It is possible that a harder rate of perceived exertion (RPE) during exercise for those with T2D as compared with nondiabetics may be a barrier to physical activity. This study examined RPE (Borg scale, ordinal range 6–20) during submaximal exercise at identical absolute work rates to test the hypothesis that women with T2D demonstrate harder RPE during exercise than nondiabetic controls. In a prespecified analysis of existing data from equivalently sedentary women, RPE during submaximal exercise was compared among women with uncomplicated T2D (n = 13, mean body mass index (BMI) 34.2, mean hemoglobin A1c 9%), overweight controls (OC, n = 13, mean BMI 30.7), and normal-weight controls (NWC, n = 13, mean BMI 23.1). Subjects performed three 7 min, constant-load exercise tests at 20 W and 30 W. Mixed-effects general linear modeling was used to test for differences in mean RPE estimates among groups with and without adjustment for relative work intensity, age, habitual physical activity, or BMI. Subjects with T2D perceived harder effort during bicycling exercise than controls, as measured by RPE at 20 W and 30 W (p < 0.05 for T2D vs. OC and for T2D vs. NWC). Adjusting for relative work intensity eliminated significant group RPE differences at 30 W, but group RPE differences at 20 W remained significant. Harder perceived effort during exercise may be a barrier to physical activity for those with T2D.
Sodium food sources in the Canadian diet
Authors: Fischer Peter W.F. , Vigneault Michel , Huang Rong , Arvaniti Konstantinia , Roach Paula
Published: November 2009

The purpose of this study is to provide information on the current sources of dietary sodium in the Canadian food supply to provide a baseline to measure against the effectiveness of strategies to reduce salt consumption. Such strategies are being developed by a Health Canada-led multistakeholder Working Group. Data from the 2004 Canadian Community Health Survey (CCHS) 2.2, Nutrition, were used to determine the leading food group contributors of sodium in the diet. The total sample size was more than 35 000 respondents. The results from this study were reported for 4 age and sex groups, namely, youths aged 1 to 8 years, youths aged 9 to 18 years, males aged 19 years and older, and females aged 19 years and older. Average daily intakes of sodium for these groups were 2388 mg, 3412 mg, 3587 mg, and 2684 mg, respectively. In all cases these intakes exceeded the tolerable upper intake level (UL) established by the Institute of Medicine, as well as targets set by the governments of the United Kingdom and the United States and the World Health Organization. The contribution of sodium to the food supply by the top 40 food groups is presented for each of the age and sex groups. The key food group contributors of sodium are breads (13.88%), processed meats (8.90%), and pasta dishes (5.67%). Although breads are found to be major contributors of sodium, this is mainly because of the large consumption, rather than a high concentration of sodium. Higher-sodium foods, such as processed meats, are eaten in smaller quantities but, because of their sodium density, contribute significant amounts of sodium to the diet of Canadians. Some very high sodium foods, such as frozen dinners, are eaten by only a small proportion of the population, but for those consuming these, the sodium could contribute a significant proportion of the UL just from a single meal.
A meta-analysis of the effects of conjugated linoleic acid on fat-free mass in humans
Authors: Schoeller Dale A. , Watras Abigail C. , Whigham Leah D.
Published: November 2009

Treatment of laboratory animals with a 50:50 mixture of c9,t11 and t10,c12 conjugated linoleic acid (CLA) results in fat loss and, to a smaller degree, fat-free mass (FFM) gain. In a previous meta-analysis, we found that CLA produced a fat loss, but that humans were not as responsive as mice. We performed a similar meta-analysis in the same 18 studies to test whether CLA increased FFM. Only placebo-controlled trials that measured body composition were included. We found that FFM increased during CLA treatment (0.3 ± 0.7 kg; p = 0.05), but that the change did not display an effect of length of treatment (0.001 ± 0.005 kg·week–1; p = 0.8), or an effect of dosage (0.1 ± 0.1 kg·g CLA–1·day–1; p = 0.3). We conclude that FFM does increase in humans during CLA treatment, but the onset of the increase is rapid and the total increase is small (<1%).
Experimental and clinical research findings on the cardiovascular benefits of consuming flaxseed
Authors: Bassett Chantal M.C. , Rodriguez-Leyva Delfin , Pierce Grant N.
Published: November 2009

Functional foods and nutraceuticals are becoming popular alternatives to pharmacological treatments by providing health benefits and (or) reducing the risk of chronic diseases. Flaxseed is a rich source of 3 components with demonstrated cardioprotective effects: the omega-3 fatty acid α-linolenic acid (ALA), dietary fibre, and phytoestrogen lignans. Multiple clinical dietary intervention trials report that consuming flaxseed daily can modestly reduce circulating total cholesterol (TC) by 6%–11% and low-density lipoprotein (LDL) cholesterol by 9%–18% in normolipemic humans and by 5%–17% for TC and 4%–10% for LDL cholesterol in hypercholesterolemic patients, as well as lower various markers associated with atherosclerotic cardiovascular disease in humans. Evidence to date suggests that the dietary fibre and (or) lignan content of flaxseed provides the hypocholesterolemic action. The omega-3 ALA found in the flaxseed oil fraction also contributes to the antiatherogenic effects of flaxseed via anti-inflammatory and antiproliferative mechanisms. Dietary flaxseed may also protect against ischemic heart disease by improving vascular relaxation responses and by inhibiting the incidence of ventricular fibrillation.
Oxygen uptake kinetics: historical perspective and future directions
Authors: Hughson Richard L.
Published: November 2009

Oxygen uptake has been studied in the transitions between rest and exercise for more than 100 years, yet the mechanisms regulating the rate of increase in oxidative metabolism remain controversial. Some of the controversy is a consequence of incorrect interpretations of kinetic parameters describing amplitude and time constant relationships, whereas other factors relate to an incomplete framework for interpretation of experimental results. In this review, a new conceptual 3-dimensional model is proposed to explore the intracellular environment of skeletal muscle in the rest-to-exercise transition. The model incorporates the so-called “metabolic inertia” describing the increases in metabolic substrates and enzyme activation, along with the dynamic changes in intracellular partial pressure of oxygen (PO2). Considerable evidence exists during normal submaximal exercise challenges for an effect of changes in O2 delivery to working muscles affecting the intracellular PO2 (displayed on the x axis) and the high energy phosphate concentration (y axis) during steady-state exercise as well as the transitions from rest to exercise. The z axis incorporates a hypothetical description of metabolic inertia that is enhanced by increased enzyme activation and production of metabolic substrates. Specific examples are given that describe how this axis can affect oxygen uptake kinetics within the context of changing intracellular PO2 and energetic states. Oxidative metabolism at the onset of exercise is regulated by a dynamic balance of O2 transport and utilization mechanisms and is not limited solely by metabolic inertia.
A combination of pH-sensitive caplet coatings may be an effective noninvasive strategy to deliver bioactive substances, nutrients, or their precursors to the colon
Authors: Aimone Ashley M. , Connolly Bairbre , Chaudhary Surinder , Lugtu-Pe Jamie , Martinuzzi Frank , Pencharz Paul , O’Connor Deborah L.
Published: November 2009

We hypothesize that bacterially synthesized nutrients in the large intestine may significantly influence the nutritional status of humans and, specifically, that of the colonocytes. In vivo research with human subjects in this area has been extremely limited because of the absence of a noninvasive means to quantitatively deliver test doses of nutrients, or their precursors, to the colon. The purpose of this study was to design and test the effectiveness of a pH-dependent coating in delivering intact placebo caplets to the large intestine. Barium sulphate caplet cores (19.1 mm × 9.7 mm) were coated with 2 different pH-dependent acrylic copolymer products, Eudragit L100 and S100, in either a 1:0 ratio (100% Eudragit L100) or 3:1 ratio (75% Eudragit L100 and 25% S100). The disintegration profile of each formulation was determined through in vitro testing, then caplets were sequentially administered to 10 healthy volunteers, and monitored in vivo via serial abdominal fluoroscopic images. Test caplets with the 3:1 coating formulation had a 40% higher colon-targeting specificity compared with the 1:0-coated caplets, and tended to begin disintegrating at a later time after administration (p = 0.09). The total time from administration to complete disintegration was also significantly longer for the 3:1-coated caplets (p = 0.003). These results suggest that barium sulphate caplets with a 3:1 acrylic copolymer coating formulation ratio (Eudragit L100 and S100) may be a suitable delivery system for quantifying the biosynthesis of nutrients in the human large intestine and measuring their absorption across the colonic epithelium.
Resistance exercise and nutrition to counteract muscle wasting
Authors: Little Jonathan P. , Phillips Stuart M.
Published: November 2009

Loss of muscle mass is an unfavourable consequence of aging and many chronic diseases. The debilitating effects of muscle loss include declines in physical function and quality of life and increases in morbidity and mortality. Loss of muscle mass is the result of a decrease in muscle protein synthesis, an increase in muscle protein degradation, or a combination of both. Much research on muscle wasting has tended to focus on preventing muscle protein breakdown, and less attention has been paid to providing adequate stimulation to increase muscle protein synthesis. In this review, we present evidence to suggest that interventions aimed at increasing muscle protein synthesis represent the most effective countermeasure for preventing, delaying, or reversing the loss of skeletal muscle mass experienced in various muscle wasting conditions. Based on results from acute and chronic studies in humans in a wide variety of wasting conditions, we propose that resistance exercise training combined with appropriately timed protein (likely leucine-rich) ingestion represents a highly effective means to promote muscle hypertrophy, and may represent a highly effective treatment strategy to counteract the muscle wasting tassociated with aging and chronic disease.
Cola intake and serum lipids in the Oslo Health Study
Authors: Høstmark Arne Torbjørn , Tomten Sissel Erland
Published: November 2009

Soft drinks can be a major source of sucrose, which may influence serum lipid concentration. We have examined the association between intake frequency of various types of soft drinks and the concentration of serum triglycerides (TG) and high-density lipoprotein (HDL) and low-density lipoprotein (LDL) cholesterol in the cross-sectional Oslo Health Study. A total of 14 188 subjects of the altogether 18 770 participants of the study had data on intake frequency of colas and non-colas, with or without sugar. The population sample consisted of both sexes and 3 age groups: group1 (30 years of age), group 2 (40 and 45 years of age), and group 3 (59–60 years of age). In both sexes, HDL decreased and TG increased significantly (p < 0.001) with increasing intake frequency of colas. In contrast, no consistent associations were found between the reported intake of non-cola soft drinks and the serum lipids. We found no significant differences related to the reported presence or absence of sugar in the soft drinks. In multiple linear regression analyses, the colas vs. serum lipid associations prevailed (p < 0.001) after including 13 possible confounders: sex; age group; time since last meal; physical activity; intake of alcohol, coffee, cheese, fruit and (or) berries, and fatty fish; smoking; length of education; use of cholesterol-lowering drugs; and intake of non-colas. Thus, the self-reported intake frequency of colas, but not other soft drinks, was negatively associated with serum HDL, and positively associated with TG and LDL.
Forskolin attenuates the action of insulin on the Akt–mTOR pathway in human skeletal muscle
Authors: Richmond Scott R. , Touchberry Chad D. , Gallagher Philip M.
Published: November 2009

Forskolin (FSK) is capable of both stimulating and inhibiting the intracellular signaling pathways of protein synthesis tissues other than skeletal muscle. The purpose of this investigation was to determine if FSK administration affects various elements of the protein kinase B (Akt)–mammalian target of rapamycin (mTOR) pathway in human skeletal muscle. Ten (n = 10) healthy, young (21.6 ± 1.3 years), nonobese (body mass index = 25.5 ± 3.5 kg·m–2), recreationally active males were selected for participation. Following an 8 h fast, 2 muscle biopsies of the vastus lateralis were performed. The samples were sectioned and exposed to 4 in vitro treatment conditions: basal, FSK, insulin (INS), and FSK+INS. The samples were then analyzed for total and phosphorylated levels of Akt, mTOR, S6 kinase (S6K1), and 4E binding protein (4EBP1). Akt phosphorylation was significantly greater in the INS-treated samples compared with the basal and FSK conditions (p = 0.007). Furthermore, the ratio of phosphorylated Akt to total Akt (P/T) was higher in the INS samples compared with the basal and FSK samples (p = 0.001). There were no differences in mTOR phosphorylation among the 4 groups; however, total mTOR was significantly greater in the FSK+INS group (p = 0.006). There were also no differences in phosphorylated or total levels of S6K1 among the 4 groups. However, 4EBP1 phosphorylation was significantly greater in the INS-treated samples compared with the basal (p = 0.003) and FSK (p = 0.004) treatments. There were no differences in the ratio of phosphorylated 4EBP1 to total 4EBP1 (P/T) among the 4 groups. These results indicate that FSK does not activate the Akt–mTOR pathway in human skeletal muscle; however, these results suggest that FSK may inhibit the actions of INS on this pathway.
Is there a gender difference between ACE gene and race distance?
Authors: Min Seok-Ki , Takahashi Kazuei , Ishigami Hideaki , Hiranuma Kenji , Mizuno Masuhiko , Ishii Takashi , Kim Chang-Sun , Nakazato Koichi
Published: November 2009

We aimed to examine the association between the angiotensin I-converting enzyme ( ACE ) gene (insertion (I) and deletion (D)) polymorphism in Japanese university track athletes and race distance, as well as to evaluate the gender effects on this association. The ACE I/D allele frequency was determined in 277 athletes (176 men, 101 women; aged 19.7 ± 1.2 years), who were then grouped on the basis of their major competitive race distances (short distance (SD), ≤200 m; middle distance (MD), 400–800 m, and long distance (LD), ≥1500 m). The ACE I allele frequency increased with the distance (44.4%, 48.4%, and 66.2% for the SD (n = 107), MD (n = 62), and LD (n = 108) groups, respectively; p < 0.001, χ2 test). On multinomial logistic regression analysis, significant associations between ACE genotype and race distance were observed only in male athletes (ID vs. SD, p = 0.004; ID vs. LD, p = 0.030; II vs. LD, p = 0.001). There was no significant association between ACE genotype and race distance in female athletes. We conclude that the ACE I allele is overrepresented in endurance athletes, and that its frequency varies depending on gender.
An internal blast analysis of a steel box memberThis article is one of a selection of papers published in the Special Issue on Blast Engineering.
Authors: Wong Wai Tak
Published: November 2009

This paper presents a unique approach that can be used for the analysis of a blast due to an internal detonation. The information in this paper focuses on understanding the blast effects in a confined environment, blast loads prediction, and response analysis using computer codes and finite element modeling methods. An example is included in which a partial segment of a steel box member is analyzed for its response to an internal blast using blast prediction tools and finite element code.
Response sensitivity of blast-loaded reinforced concrete structures to the number of degrees of freedomThis article is one of a selection of papers published in the Special Issue on Blast Engineering.
Authors: El-Dakhakhni W. W. , Changiz Rezaei S. H. , Mekky W. F. , Razaqpur A. G.
Published: November 2009

Accurate analysis of reinforced concrete (RC) structures under blast loading is very complicated due to the nonlinear behaviour of concrete and reinforcement and the various failure modes to be considered. Although blast loads can excite a large number of modes due to their high frequency content, practical computational tools are usually limited to single-degree-of-freedom (SDOF) models. In addition to oversimplification, SDOF models are known to give inaccurate prediction for shear forces and support reactions. This is because accurate shear force prediction typically requires accounting for modes higher than the fundamental mode. In this study, a multi-degree-of-freedom (MDOF) model is developed that takes into account the nonlinear behaviour of RC structures and the material strength and deformation dependency on the strain rate. Using this model, a series of dynamic analyses were carried out for two typical structural members, with different combination of blast pressure and impulse. The effect of varying the number of degrees of freedom (DOF) was investigated through increasing the number of nodes used to descretize each structural member. The results of the developed MDOF model were compared to the results of available SDOF models which demonstrated the deficiencies of the latter. The developed MDOF model, with few DOF, was found to be capable of accurately predicting the dynamic shear of the modeled structural members. The model was also compared to available experimental results and showed good agreement. Changing the number of DOF also affected the pressure–impulse (P–I) diagrams for the structural member significantly, especially in the impulsive regime.
Experimental study of the strength and deformations of carbon fibre reinforced polymer (CFRP) retrofitted reinforced concrete slabs under blast loadThis article is one of a selection of papers published in the Special Issue on Blast Engineering.
Authors: Razaqpur A. Ghani , Contestabile Ettore , Tolba Ahmed
Published: November 2009

The blast response and ultimate resistance of reinforced concrete slabs externally strengthened with carbon fibre reinforced polymer (CFRP) laminates were investigated. Five square slab specimens, 1 m on a side, were retrofitted with 500 mm wide CFRP laminates bonded to their top and bottom surfaces. Another four nominally identical unretrofitted slabs were used as control specimens. Four of the retrofitted and the four control slabs were first subjected to the detonation of either 22.4 or 33.4 kg of explosive at a stand-off distance of 3.0 m. For reference, the fifth retrofitted slab was only statically tested to failure. Blast pressures and impulses and slab deformations were measured. After exposure to the blast, the slabs that were not completely damaged were statically tested to failure. Overall the retrofitted slabs performed better than the control slabs, but one retrofitted slab completely failed under the blast load while none of the control slabs experienced complete failure under similar load.
Fundamental concepts in blast resistance evaluation of structuresThis article is one of a selection of papers published in the Special Issue on Blast Engineering.
Authors: Razaqpur G. , Mekky Waleed , Foo S.
Published: November 2009

This study critically discusses the fundamental concepts used for evaluating the flexural and axial resistance of structures under blast. Simplified methods based on single degree of freedom are emphasized. The paper begins with how to estimate the blast parameters for a given charge size and standoff distance. These parameters include side-on and reflected pressures, positive phase duration, and side-on and reflected impulses. Subsequently, blast damage criteria are defined in accordance with prevailing guidelines and some of their short comings are discussed. To assess the impact of blast on the flexural safety and performance of structures, some simple methods are presented. The methods are either empirical or are based on the principles of energy and momentum conservation. The analytical results are in closed-form or in the form of pressure–impulse (P–I) diagrams. The effect of strain rate on both blast-induced flexural deflection and strength of structures, with particular emphasis on reinforced concrete structures, is discussed.
Behaviour of steel reinforced polymer (SRP) strengthened RC members under blast loadThis paper is one of a selection of papers in the Special Issue on Blast Engineering.
Authors: Carriere M. , Heffernan P.J. , Wight R.G. , Braimah A.
Published: November 2009

During the past decade, significant research has been carried out on the strengthening of reinforced concrete (RC) slabs, beams, and columns using externally bonded carbon fibre reinforced polymer (CFRP) sheets. Steel reinforced polymer (SRP) sheets have recently been proposed as an alternative to CFRP to strengthen reinforced concrete beams. This paper reports experimental and numerical results of RC beams and beam-columns transversely wrapped with SRP and tested under blast load. A total of 10 scaled RC members were tested at a variety of blast wave intensities. Detailed observations are reported and validated against numerical models created in AUTODYN for the unstrengthened RC members. The SRP wraps were resilient in the near-field blast range and enhanced the ductility of the concrete likely through enhanced confinement. Member capacity could be increased by the wraps in failure modes dominated by concrete crushing. AUTODYN appears able to reasonably predict the behaviour of the RC members when loaded by blast.
Protocols for the analysis of transformer oil and its degradation in soil by hydrogen peroxideA paper submitted to the Journal of Environmental Engineering and Science.
Authors: Chang Yanjun , Achari Gopal , Langford Cooper H.
Published: November 2009

Conventional gas chromatography (GC) analysis of hydrocarbons displaying one broad peak provides limited information. Two GC analytical protocols using two-peak and three-peak approaches were developed to investigate transformer oil components and their degradation in soil by hydrogen peroxide. The two-peak method revealed transformer oil to be composed of 27 wt.% F2 fraction and 73 wt.% F3 fraction hydrocarbons. The three-peak method segregated the transformer oil into 40 wt.% light, 40 wt.% medium, and 20 wt.% heavy hydrocarbon fractions. In contrast to reports of success with several classes of lighter hydrocarbons, only limited degradations of transformer oil in soils by 15% and 30% hydrogen peroxide treatment was indicated by conventional one-peak analysis; two-peak analysis showed varying F2 and F3 fraction degradations with F2 fraction degradation being higher; three-peak analysis offered a richer understanding of the relative degradations of light, medium, and heavy fractions. The effect of a low pH environment on the degradation of transformer oil by hydrogen peroxide was evaluated using the three-peak method. It emerged that the degradation of the medium and heavier fractions of transformer oil was higher at pH 2.0.
Triaxial frequency sweep characterization of Saskatchewan hot mix asphaltic concrete across asphalt cement binder type
Authors: Berthelot Curtis , Podborochynski Diana , Wandzura Colin , Prang Colin , Marjerison Brent
Published: November 2009

The purpose of this research was to determine how asphalt cement binder types influence the mechanical behaviour of hot mix asphalt concrete mixes. This research employed triaxial frequency sweep characterization of a typical City of Saskatoon Hot Mix Type A2 and a typical Saskatchewan Ministry of Highways and Infrastructure Hot Mix Type 70 across a range of triaxial load frequencies and stress states representative of Saskatchewan field state conditions. The asphaltic mixes were evaluated across four asphalt cement binder types typically employed by Saskatchewan road agencies. Based on the findings of this study, the mechanical behaviour of both asphalt mixes evaluated were found to be highly sensitive to load rate, stress state, as well as asphaltic binder type. It was concluded that load rate, field stress state, and asphalt binder type should be incorporated into the structural design of hot mix asphalt concrete pavements to ensure adequate mix performance, particularly when placed in severe field conditions.
Numerical simulation of sharp-crested weir flows
Authors: Qu J. , Ramamurthy A.S. , Tadayon R. , Chen Z.
Published: November 2009

The sharp-crested weir in a rectangular open channel can be used as a simple and accurate device for flow measurement and control in open channels. However, in the past, the solution to this problem was found mainly on the basis of experimental data or through the development of simplified theoretical expressions. In the present study, k-ε turbulence model is applied to obtain the flow parameters such as pressure head distributions, velocity distributions, and water surface profiles. The predictions of the proposed numerical model are validated using existing experimental data. The k-ε turbulence model developed is used to predict the characteristics of a sharp-crested weir in a rectangular open channel. The volume of fluid (VOF) scheme is used to find the shape of the free surface. A properly validated model permits one to obtain the flow characteristics of the sharp-crested weir for a wide range of weir and hydraulic parameters without recourse to expensive and more time consuming experimental methods. Further, the model permits one to incorporate small changes in the geometric parameters involving small changes in inlet and outlet conditions and study their impact on the weir flow characteristics.
Reference evapotranspiration forecasting using different artificial neural networks algorithms
Authors: Chauhan Seema , Shrivastava R. K.
Published: November 2009

The present study aims to apply artificial neural networks (ANNs) for reference evapotranspiration (ETo) prediction. Three different feed-forward artifical neural network (ANN) models, each using varied input combinations of previous months ETo, have been trained and tested. The output of the network was the one-month-ahead ETo. The networks learned to forecast one-month-ahead ETo for Mahanadi reservoir project area using the three learning methods namely quasi-Newton algorithm, Levenberg–Marquardt algorithm and backpropagation with adaptive learning rate algorithm. The training results were compared with each other, and performance evaluations were done for untrained data. The performance evaluations measured were standard error of estimates (SEE), raw standard error of estimates (RSEE), and model efficiency. The best ANN architecture for prediction of ETo was obtained for Mahanadi reservoir project area. The monthly reference evapotranspiration data were estimated by the Penman–Monteith method and used for training and testing of the ANN models. Further ANNs predicted results were compared with those obtained using the statistical multiple regression technique. Based on results obtained, the ANN model with architecture of 3–9-1 (three, nine, and one neuron(s) in the input, hidden, and output layers, respectively) trained using quasi-Newton algorithm was found to be the best amongst all the models with minimum SEE and RSEE of 0.45 and 0.45 mm/d respectively and maximum model efficiency of 93%. It is concluded that ANN can be used to predict ETo.
New design equations for channel shear connectors in composite beams
Authors: Pashan Amit , Hosain M. U.
Published: November 2009

This paper briefly summarizes the results of an experimental research project involving the testing of push-out specimens with channel shear connectors. The test program consisted of three series, each with 12 push-out specimens. In each series, six specimens had solid concrete slabs and the other six specimens had concrete slabs incorporating wide-ribbed metal deck with ribs parallel to the beam. The test parameters included the compressive strength of concrete and the length and web thickness of the channel shear connector. The test results showed that, for a given length of channel, the concrete strength dictates the failure mode. In specimens with higher strength concrete, failure was caused by the fracture of the channel web. Concrete crushing–splitting was the observed mode of failure in specimens with solid slabs when lower strength concrete was used. A concrete shear plane type of failure was observed in most of the specimens with metal deck slabs. The strengths of concrete used ranged from 21 MPa to a maximum of 35 MPa.
Application of a flow-measurement structure for sediment-laden streams
Authors: Göğüş Mustafa , Gerek A. Cüneyt , Altan-Sakarya A. Burcu
Published: November 2009

Generally, measurement of flow in natural streams is accomplished by measuring the flow depth. Hence, the relationship between the water level and discharge should be obtained in advance. However, in streams with high sediment load, the bottom level may change due to sediment deposition, preventing the single relation between water level and discharge. This paper summarizes the application of a flow-measurement structure for sediment-laden streams. The proposed structure is designed and built in Turkey and has been under operation since 1998 without any sedimentation problem. The agreement between the real data obtained from the structure and the theoretical rating curve is quite reasonable.
Effects of surface preparation, thickness, and material on asphalt pavement overlay transverse crack propagation
Authors: Hong Feng , Chen Dar-Hao
Published: November 2009

Asphalt overlay has been widely used in pavement rehabilitation. The most frequently observed distress in an asphalt overlay is transverse cracking. In this study, the Texas long-term pavement performance (LTPP) specific pavement study 5 (SPS-5) test sections are highlighted. Three key factors affecting overlay cracking performance are investigated: (i) surface preparation, (ii) overlay thickness, and (iii) material. A deterioration model is developed to evaluate the effects of these factors. The deterioration process is well captured by incorporating both engineering principles and statistical modeling techniques, and the effects of the three key factors are thoroughly evaluated. The results suggest that (i) milling of existing pavement does not help reduce overlay transverse cracking if existing cracking is not completely removed, (ii) thicker overlay contributes to transverse crack resistance, (iii) Texas type C asphalt mixture is more effective in resisting transverse cracks than type B asphalt mixture (with coarser aggregate and less binder than type C), and (iv) overlays that incorporate reclaimed asphalt pavement (RAP) are more prone to transverse cracking than virgin asphalt. Furthermore, these effects are quantified based on the model estimation results.
Mechanism for initiating secondary currents in channel flows
Authors: Yang Shu-Qing
Published: November 2009

This study investigates the underlying mechanisms that initiate secondary flow in developing turbulent flow along a corner. This is done by theoretical examination of the total shear stress, which is the time-averaged product of instantaneous streamwise velocity U and the velocity Vnnormal to the interface. The study shows that lines of zero total shear stress exist in the flow region, which delineate the region of secondary flow. Therefore, the flow region is dividable and eight vortices occur in a duct flow. The theoretical and experimental results show that the division line, separating the neighboring secondary currents in a corner, is not always identical to the bisector of the corner, but deviates from the corner bisector if the aspect ratio is b/h ≠ 1. By simplifying Reynolds equation in the near-bed region, we find that theoretically a lateral variation of streamwise velocity initiates the wall-tangent flow that drives the vortex in the region bounded by zero total shear stress. A simplified method for estimating the vortex center, near-bed secondary velocity, and shape of secondary currents has been proposed, and a good agreement between the measured and predicted features is achieved.
Simple iteration method for structural static reanalysis
Authors: Liu Haifeng , Wu Baisheng , Li Zhengguang
Published: November 2009

This paper presents a simple iterative method for structural static reanalysis. A preconditioned Richardson’s iterative method is developed and the relaxation parameter is determined by a very simple formula derived from the corresponding potential energy function. Based on the iteration method, an acceleration technique is also established. The proposed method is intended to utilize the existing stiffness matrix factorization completed for the initial design, require matrix-by-vector products only, preserve the ease of implementation and improve significantly the quality of the results. The method is suitable for general finite element systems. Calculation of derivatives is not required. The computational time is considerably reduced. A numerical example is used to validate the effectiveness of the proposed reanalysis method.
Mix-design method of self-compacting concretes for pre-cast industry
Authors: Shen J. , Yurtdas I. , Diagana C. , Li A.
Published: November 2009

Some mix-design methods for self-compacting concrete (SCC) have been proposed since the 1990s, but these methods do not address all practical needs. This paper proposes a method that enables the composition of SCC to be designed for a given strength (in this study, from 10 to 50 MPa at age 1 day or from 30 to 70 MPa at age 28 days). In this method, the compressive strength of SCC at an early age is considered an important parameter to answer the needs of the precast industry. The proposed mix-design method is based on optimizing the packing density of aggregates and ensuring the necessary quantity of paste to fill the voids between aggregates and to provide good fluidity of the SCC. The compressive strength of SCC can be estimated according to the Bolomey formula, and the quantity of superplasticizer can be determined by the proposed method.
Response of earthquake-resistant reinforced-concrete buildings to blast loadingThis article is one of a selection of papers published in the Special Issue on Blast Engineering.
Authors: Saatcioglu Murat , Ozbakkaloglu Togay , Naumoski Nove , Lloyd Alan
Published: November 2009

Recent bomb attacks on buildings have raised awareness about the vulnerability of structures to blast effects. The resiliency of structures against blast-induced impulsive loads is affected by structural characteristics that are also important for seismic resistance. Deformability and continuity of structural elements, strength, stiffness, and stability of the structural framing system and resistance to progressive collapse are factors that play important roles on the survivability of buildings under both blast and seismic loads. The significance of these structural parameters on blast resistance of reinforced concrete buildings is assessed through structural analysis. Both local element performance and global structural response are considered while also assessing the progressive collapse potential. The buildings under investigation include 10-storey moment resisting frames with or without shear walls. The blast loads selected consist of different charge-weight and standoff distance combinations. The results are presented in terms of ductility and drift demands. They indicate improved performance of seismic-resistant buildings when subjected to blast loads, in terms of local column performance, overall structural response, and progressive collapse potential.
Methodology for integrating fuzzy expert systems and discrete event simulation in construction engineering
Authors: Shaheen Ahmed A. , Fayek Aminah Robinson , AbouRizk Simaan M.
Published: November 2009

This paper demonstrates how fuzzy expert systems can be integrated within discrete event simulation models to enhance their modeling and predictive capabilities for construction engineering applications. A proposed methodology is presented for extracting the information from experts to develop the fuzzy expert system rules. The developed fuzzy expert system is integrated within a discrete event simulation model to enhance its modeling capability by explicitly accounting for the different factors affecting some of the simulation activities. A tunneling case study is used to illustrate the features of the integrated system. The outputs generated from the integrated system are very comparable to those from the original probabilistic simulation model. The integrated system represents a more realistic modeling scenario, since it thoroughly accounts for the different factors affecting the tunnel boring machine (TBM) advance rate. This paper is relevant to researchers because it provides an advance in combining artificial intelligence techniques with simulation models to yield better tools for construction modeling. It is of relevance to practitioners because it provides a useful tool for modeling construction engineering problems.
Optimal proportioning for hot recycled mix design under Superpave mix design consideration
Authors: Swamy Aravind Krishna , Das Animesh
Published: November 2009

While performing recycled (central plant) hot mix design as per Superpave mix design criteria, the quantity of reclaimed asphalt pavement (RAP) is either assumed fixed, or estimated from other fixed parameter(s). In either of the cases, the constituent (RAP, virgin binder, and virgin aggregates) proportions may not necessarily represent a cost-optimal situation. The present paper develops a generalized formulation for preliminary constituent proportioning of hot recycled mix following Superpave criteria. Through this formulation an optimal solution for mix proportion can be obtained, where the total material cost is minimized while satisfying all the binder and mix property requirements.
Two-dimensional model for predicting performance of aerated grit chambersA paper submitted to the Journal of Environmental Engineering and Science.
Authors: Munoz Alex , Young Stephanie
Published: November 2009

A two-dimensional model was developed in this study. The model predicts the performance of a full-scale aerated grit chamber for grit removal from wastewater. The model numerically integrates Poisson’s equation, which describes the motion of the liquid induced by the rising air bubbles. The model makes use of finite element algorithms available in Mathcad to solve Poisson’s equation. The model was developed for predicting the velocity field in the chamber. The model was used to perform a sensitivity analysis of the design variables that affect the performance of an existing grit chamber at the Moose Jaw Wastewater Treatment Plant. The results of the sensitivity analysis indicate that predictions of velocity field are highly sensitive to energy transfer efficiency, air flowrate, and particle settling velocity but less sensitive to variations of wastewater flowrate, diffuser depth, and grid spacing.
Getting to the center of X-chromosome inactivation: the role of transgenesThis paper is one of a selection of papers published in this Special Issue, entitled 30th Annual International Asilomar Chromatin and Chromosomes Conference, and has undergone the Journal’s usual peer review process.
Authors: Minks Jakub , Brown Carolyn J.
Published: November 2009

X-chromosome inactivation is a fascinating epigenetic phenomenon that is initiated by expression of a noncoding (nc)RNA, XIST, and results in transcriptional silencing of 1 female X. The process requires a series of events that begins even before XIST expression, and culminates in an active and a silent X within the same nucleus. We will focus on the role that transgenic systems have served in the current understanding of the process of X-chromosome inactivation, both in the initial delineation of an active and inactive X, and in the function of the XIST RNA. X inactivation is strictly cis-limited; recent studies have revealed elements within the X-inactivation center, the region required for inactivation, that are critical for the initial regulation of Xist expression and chromosome pairing. It has been revealed that the X-inactivation center contains a remarkable compendium of cis-regulatory elements, ncRNAs, and trans-acting pairing regions. We review the functional componentry of the X-inactivation center and discuss experiments that helped to dissect the XIST/Xist RNA and its involvement in the establishment of facultative heterochromatin.