bluuebunny/crossref_metadata_2025 huggingface dataset:
Allelism and molecular mapping of soybean necrotic root mutants
Authors: Palmer Reid G. , Zhang Lei , Huang Zhiping , Xu Min
Published: April 2008

Mutability of the w4 flower color locus in soybean, Glycine max (L.) Merr., is conditioned by an allele designated w4-m. Germinal revertants recovered among self-pollinated progeny of mutable plants have been associated with the generation of necrotic root mutations, chlorophyll-deficiency mutations, and sterility mutations. A total of 24 necrotic root mutant lines were generated from a total of 24 independent reversion events at the w4-m locus. The initial mutable population included 4 mutable categories for w4-m, designated (1) low frequency of early excisions, (2) low frequency of late excisions, (3) high frequency of early excisions, and (4) high frequency of late excisions. These mutable categories were based upon flower phenotype, i.e., somatic tissue. A total of 22 of 24 necrotic root mutations occurred from germinal reversions classified in the high frequency of excision categories. Of these 22 mutants, 14 came from early excisions and 8 came from late excisions. These necrotic root mutants were allelic to 6 previously identified necrotic root mutants derived from the study of germinal revertants, i.e., gene tagging studies, chemical mutagenesis, and “spontaneous” occurrences from genetic crosses. Thus, all 30 necrotic root mutants in soybean are allelic. An F2mapping population from the cross of Minsoy (Rn1 Rn1) × T328 (rn1 rn1) was used to map the Rn1 locus using simple sequence repeat (SSR) markers. The Rn1 locus was located between Satt288 and Satt612 on molecular linkage group G.
Super-single tire loadings and their impacts on pavement design
Authors: Kim Daehyeon
Published: March 2008

Pavement design and analysis are generally performed based on the load equivalent factor (LEF) obtained from conventional dual tires and assume that the contact stress is equal to the tire inflation pressure. However, heavier tire loadings, such as super-single tires, produce much higher contact stresses than the inflation pressure. This results in larger deformations of subgrades, requiring advanced modeling of subgrades, such as elastic–plastic analysis. Super-single tires also have a different contact area shape from that of conventional tires. To assess the increased contact stresses by super-single tires, realistic contact stress distribution and contact area ratio for super-single tires should be used in the analysis. Three-dimensional finite element analyses of typical flexible pavements were done to evaluate the effects of the increased contact stresses of tire loadings on the subgrades, including load equivalency factors, overlay effect, and subgrade improvement as the behavior of subgrades becomes more important due to the increased contact stresses. Analysis results indicate that the increased contact stresses should be taken into account in the pavement structure design, as well as design of overlay or subgrade improvement. Based on the numerical results, simple design examples are suggested.
Layout and size optimization of tree-like pipe networks by incremental solution building ants
Authors: Afshar M. H.
Published: March 2008

Application of an ant colony optimization algorithm (ACOA) for simultaneous layout and size optimization of tree-like pipe networks is described in this paper using two different formulations. In the first formulation, each link of the base graph is considered as the decision point of the problem. Each decision point is considered in turn and the ants are then required to choose any of the available options at the current decision point. The list of available pipe diameters with the null option included for each link constitutes the available options in this formulation. In the second approach, the network nodes are considered as the decision points of the problem. The available options in this formulation are represented by the list of allowable pipe diameters for all plausible links such that the resulting network is a tree network. The plausible links at each decision point are provided by a tree-growing algorithm. This formulation leads to a very small search space compared with the first algorithm, as each ant is now forced to create a feasible solution regarding the layout geometry of the network. This approach fully exploits the sequential nature of the ACOA in building solutions, which is believed to be one of the main advantages of these algorithms compared with other general metaheuristics. The proposed methods are applied to find the optimal layout of two benchmark examples in the published literature and the results are presented and compared with the existing results.
Impacts of cathodic protection on pipe break probabilities: a Toronto case study
Authors: Schuster C. J. , McBean E. A.
Published: March 2008

The pipe break database of the Greater Toronto Area (GTA), dating from 1960, is used to quantify the impacts of cathodic protection (CP) on the frequency of pipe breaks. The findings demonstrate that the average time between pipe breaks increases by up to an average of almost 4 years for ductile iron pipes after CP is placed on a pipe. Further, the probability of a pipe break occurring 10 years after the application of CP decreases in comparison with pipes that have not been cathodically protected. The cost savings for CP are substantial, with the repair costs (including the cost of CP implementation) decreasing to one-third for ductile iron (DI) pipes of 150 mm diameter and to one-half for DI pipes of 300 mm diameter. The cost savings for cast iron (CI) pipes are not as dramatic, but still demonstrate a reduction to 60% of the repair costs for 150 mm diameter pipes and to 70% of the repair costs for 300 mm diameter pipes.
Sustainable precast concrete foundation system for residential construction
Authors: Yu Haitao , Al-Hussein Mohamed , Nasseri Reza , Cheng Roger J.
Published: March 2008

Residential construction has changed little in decades. In North America, houses are constructed predominantly with cast-in-place (CIP) concrete basement foundations and “custom-built” wood platform – framing structures. To improve the productivity of residential construction, a precast concrete foundation (PCF) system was developed by the University of Alberta and its industrial partners. Although the PCF system can be built much faster and better than conventional CIP foundations, it has not been considered a viable alternative in residential construction due to the belief that it is costly and less flexible. To overcome this perception, special research efforts were made to address issues of manufacturability, constructability, and standardization. This paper proposes an innovative design of the PCF system that satisfies functional requirements, while obtaining a minimum total cost and achieving flexibility. The unique features include a modularized rib structure, external insulation, and simplified bolted connections. A comparative analysis between PCF and traditional CIP concrete foundation systems is also presented.
Strategic pathways for the sustainable management of water treatment plant residuals
Authors: Walsh M.E. , Lake C.B. , Gagnon G.A.
Published: April 2008

In North America, the rapid movement away from the direct discharge of water treatment plant (WTP) residual streams to receiving environments has resulted in considerable benefits to the drinking water industry in terms of enhancing environmental stewardship practices and supporting source water protection strategies. Over the past 20 years, application based research on appropriate technologies to treat residual streams such as filter backwash water (FBWW) has promoted the development of integrated process design that presents recycling as a viable residual management option. However, as utilities continue to develop and expand their main process lines to comply with more stringent government regulations encompassing both water quality and residual disposal practices, the development of sustainable residual management practices is expected to become a more prominent issue for this industry. The purpose of this paper is to present, from a critical point of view, the matrix of issues that currently exist regarding WTP residual streams and strategic pathways that would enhance future decision making processes for achieving long-term residual management solutions for the drinking water industry.
The influence of acetylsalicylic acid on oxylipin migration in Cryptococcus neoformans var.neoformansUOFS Y-1378
Authors: Sebolai Olihile M. , Pohl Carolina H. , Botes Piet J. , van Wyk Pieter W.J. , Kock Johan L.F.
Published: April 2008

In this paper we report the influence of acetylsalicylic acid on oxylipin migration in Cryptococcus neoformans var. neoformans UOFS Y-1378, previously isolated from human bone lesion. Transmission electron microscopy suggests that osmiophilic material originates in mitochondria and is deposited inside the yeast cell wall, from which it is excreted into the environment, along capsule protuberances, or through capsule detachments. Previous studies using immunogold labeling indicate that these osmiophilic layers contain 3-hydroxy oxylipins. In this study, the addition of acetylsalicylic acid (an inhibitor of mitochondrial function) in increasing amounts to the cells abrogated the migration of osmiophilic material, as well as capsule detachment from cell walls, and hence, oxylipin excretion. Consequently, we hypothesize that 3-hydroxy oxylipins are produced in mitochondria, probably via incomplete β-oxidation or fatty acid synthesis, from which they are deposited inside the cell wall and excreted through tubular protuberances attached to the surrounding capsules and (or) through detachment of these oxylipin-containing capsules.
Distribution of 3-hydroxy oxylipins and acetylsalicylic acid sensitivity in Cryptococcus species
Authors: Sebolai Olihile M. , Pohl Carolina H. , Botes Piet J. , van Wyk Pieter W.J. , Mzizi Refilwe , Swart Chantel W. , Kock Johan L.F.
Published: April 2008

Using a well tested antibody specific for 3-hydroxy oxylipins, we mapped the presence of these oxylipins in selected Cryptococcus ( Filobasidiella ) species. Immunofluorescence microscopy studies revealed that these compounds are deposited on cell wall surfaces, appendages, and collarettes. In vitro studies revealed that growth of Cryptococcus species was inhibited by acetylsalicylic acid (which is known to inhibit mitochondrial function, including the production of 3-hydroxy oxylipins) at concentrations as low as 1 mmol/L. The results suggest that acetylsalicylic acid is effective in controlling the growth of tested pathogens, probably by targeting their mitochondria. This study further expands the known function of this anti-inflammatory drug as anti-fungal agent.
Microarray analysis of Streptococcus pneumoniae gene expression changes to human lung epithelial cells
Authors: Song Xin-Ming , Connor Wayne , Jalal Shakiba , Hokamp Karsten , Potter Andrew A.
Published: April 2008

Streptococcus pneumoniae infection starts from the respiratory tract where interaction with host epithelial cells occurs. To gain more insights on pneumococcal pathogenesis, an oligonucleotide (oligo)-based microarray was used to investigate gene expression changes of one serotype 3 encapsulated pathogenic S. pneumoniae strain 82 and one unencapsulated avirulent S. pneumoniae strain R6 upon exposure to human lung epithelial cells (A549) for 1 and 3 h, respectively. We observed that genes associated with many functional categories were differentially regulated in strain 82, such as genes in pathogenesis, cell envelope, transcription, translation, transport, metabolism, and unknown functions. In contrast, few genes were changed in strain R6 except for genes in ribonucleotide biosynthesis and unknown functions. Quantitative real-time PCR analysis confirmed the microarray results for most of the genes tested. To further characterize functions of the selected genes, knockout mutants were constructed in strain R6. We demonstrated that 2 genetic loci, SP_2170 (AdcB, zinc ABC transporter) and SP_0157 (hypothetical protein), were involved in adherence to A549 cells. These data suggest that divergent gene expression changes occur in S. pneumoniae pathogenic and avirulent strains during interaction with human lung epithelial cells. Some of those genes are involved in pneumococcal pathogenesis.
SINGLE MACHINE SCHEDULING WITH JOB DELIVERY TO MINIMIZE MAKESPAN
Authors: LU LINGFA , YUAN JINJIANG
Published: April 2008

In the single machine scheduling problem with job delivery to minimize makespan, jobs are processed on a single machine and delivered by a capacitated vehicle to their respective customers. We first consider the special case with a single customer, that is, all jobs have the same transportation time. Chang and Lee (2004) proved that this case is strongly NP-hard. They also provided a heuristic with the worst-case performance ratio [Formula: see text], and pointed out that no heuristic can have a worst-case performance ratio less than [Formula: see text] unless P = NP. In this paper, we provide a new heuristic which has the best possible worst-case performance ratio [Formula: see text]. We also consider an extended version in which the jobs have non-identical transportation times and the transportation time of a delivery batch is defined as the maximum transportation time of the jobs contained in it. We provide a heuristic with the worst-case performance ratio 2 for the extended version, and show that this bound is tight.
CURRENT DEVELOPMENTS AND FUTURE CHALLENGES FOR THE CREATION OF AORTIC HEART VALVE
Authors: MORSI YOS S. , WONG CYNTHIA S.
Published: April 2008

The concept of tissue-engineered heart valves offers an alternative to current heart valve replacements that is capable of addressing shortcomings such as life-long administration of anticoagulants, inadequate durability, and inability to grow. Since tissue engineering is a multifaceted area, studies conducted have focused on different aspects such as hemodynamics, cellular interactions and mechanisms, scaffold designs, and mechanical characteristics in the form of both in vitro and in vivo investigations. This review concentrates on the advancements of scaffold materials and manufacturing processes, and on cell–scaffold interactions. Aside from the commonly used materials, polyglycolic acid and polylactic acid, novel polymers such as hydrogels and trimethylene carbonate-based polymers are being developed to simulate the natural mechanical characteristics of heart valves. Electrospinning has been examined as a new manufacturing technique that has the potential to facilitate tissue formation via increased surface area. The type of cells utilized for seeding onto the scaffolds is another factor to take into consideration; currently, stem cells are of great interest because of their potential to differentiate into various types of cells. Although extensive studies have been conducted, the creation of a fully functional heart valve that is clinically applicable still requires further investigation due to the complexity and intricacies of the heart valve.
THE ROLE OF TRANSLATIONAL INVARIANCE IN NONLINEAR GAUGE THEORIES OF GRAVITY
Authors: MARTÍN J. , TIEMBLO A.
Published: April 2008

The internal structure of the tetrads in a Poincaré nonlinear gauge theory of gravity is considered. Minkowskian coordinates becomes dynamical degrees of freedom playing the role of Goldstone bosons of the translations. A critical length allowing a covariant expansion similar to the weak field approach is deduced, the zeroth order metric being maximally symmetric (Minkowskian in some cases).
Aging and Survival: The Genetics of Life Span Extension by Dietary Restriction
Authors: Mair William , Dillin Andrew
Published: March 2008

Reducing food intake to induce undernutrition but not malnutrition extends the life spans of multiple species, ranging from single-celled organisms to mammals. This increase in longevity by dietary restriction (DR) is coupled to profound beneficial effects on age-related pathology. Historically, much of the work on DR has been undertaken using rodent models, and 70 years of research has revealed much about the physiological changes DR induces. However, little is known about the genetic pathways that regulate the DR response and whether or not they are conserved between species. Elucidating these pathways may facilitate the design of targeted pharmaceutical treatments for a range of age-related pathologies. Here, we discuss how recent work in nonmammalian model organisms has revealed new insight into the genetics of DR and how the discovery of DR-specific transcription factors will advance our understanding of this phenomenon.
Using the lymph fistula rat model to study the potentiation of GIP secretion by the ingestion of fat and glucose
Authors: Lu Wendell J. , Yang Qing , Sun William , Woods Stephen C. , D'Alessio David , Tso Patrick
Published: March 2008

Glucose-dependent insulinotropic polypeptide (GIP) is an important incretin produced in the K cells of the intestine and secreted into the circulating blood following ingestion of carbohydrate- and fat-containing meals. GIP contributes to the regulation of postprandial insulin secretion and is essential for normal glucose tolerance. We have established a method of assaying GIP in response to nutrients using the intestinal lymph fistula model. Administration of Ensure, a mixed-nutrient liquid meal, stimulated a significant increase in intestinal lymphatic GIP levels that were approximately threefold those of portal plasma. Following the meal, lymph GIP peaked at 60 min ( P < 0.001) and remained elevated for 4 h. Intraduodenal infusions of isocaloric and isovolumetric lipid emulsions or glucose polymer induced lymph GIP concentrations that were four and seven times the basal levels, respectively. The combination of glucose plus lipid caused an even greater increase of lymph GIP than either nutrient alone. In summary, these findings demonstrated that intestinal lymph contains high concentrations of GIP that respond to both enteral carbohydrate and fat absorption. The change in lymphatic GIP concentration is greater than the change observed in the portal blood. These studies allow the detection of GIP levels at which they exert their local physiological actions. The combination of glucose and lipid has a potentiating effect in the stimulation of GIP secretion. We conclude from these studies that the lymph fistula rat is a novel approach to study in vivo GIP secretion in response to nutrient feeding in conscious rats.
Tachykinin neurokinin 3 receptor signaling in cholecystokinin-elicited release of oxytocin and vasopressin
Authors: Haley Gwendolen E. , Flynn Francis W.
Published: April 2008

Neurokinin 3 receptor (NK3R) signaling has an integral role in the stimulated oxytocin (OT) and vasopressin (VP) release in response to hyperosmolarity and hypotension. Peripheral injections of cholecystokinin (CCK) receptor agonists for the CCK-A (sulfated CCK-8) and CCK-B (nonsulfated CCK-8) receptors elicit an OT release in rat. It is unknown whether NK3R contributes to this endocrine response. Freely behaving male rats were administered an intraventricular pretreatment of 250 or 500 pmol of SB-222200, a specific NK3R antagonist, or 0.15 M NaCl before an intraperitoneal or intravenous injection of CCK-8 (nonsulfated or sulfated) or 0.15 M NaCl. Blood samples were taken before intraventricular treatment and 15 min after intraperitoneal or intravenous injection, and plasma samples were assayed for OT and VP concentration. Intraperitoneal injection of both nonsulfated and sulfated CCK-8 significantly increased plasma OT levels and had no effect on plasma VP levels. Intravenous injection of sulfated CCK-8 stimulated an increase in plasma OT levels and did not alter plasma VP levels. However, intravenous injection of nonsulfated CCK-8 stimulated a significant increase in plasma levels of both OT and VP. No other studies have demonstrated CCK-8-stimulated release of VP in rat. NK3R antagonist did not alter baseline levels of either hormone. However, pretreatment of NK3R antagonist significantly blocked the CCK-stimulated release of OT in all CCK treatment groups and blocked VP release in response to intravenous injection of nonsulfated CCK-8. Therefore, central NK3R signaling is required for OT and VP release in response to CCK administration.
Carrier-mediated urea transport across the mitochondrial membrane of an elasmobranch (Raja erinacea) and a teleost (Oncorhynchus mykiss) fish
Authors: Rodela T. M. , Ballantyne J. S. , Wright P. A.
Published: April 2008

In osmoregulating teleost fish, urea is a minor nitrogen excretory product, whereas in osmoconforming marine elasmobranchs it serves as the major tissue organic solute and is retained at relatively high concentrations (∼400 mmol/l). We tested the hypothesis that urea transport across liver mitochondria is carrier mediated in both teleost and elasmobranch fishes. Intact liver mitochondria in rainbow trout ( Oncorhynchus mykiss) demonstrated two components of urea uptake, a linear component at high concentrations and a phloretin-sensitive saturable component [Michaelis constant ( Km) = 0.58 mmol/l; maximal velocity ( Vmax) = 0.12 μmol·h−1·mg protein−1] at lower urea concentrations (<5 mmol/l). Similarly, analysis of urea uptake in mitochondria from the little skate ( Raja erinacea) revealed a phloretin-sensitive saturable transport ( Km= 0.34 mmol/l; Vmax= 0.054 μmol·h−1·mg protein−1) at low urea concentrations (<5 mmol/l). Surprisingly, urea transport in skate, but not trout, was sensitive to a variety of classic ionophores and respiration inhibitors, suggesting cation sensitivity. Hence, urea transport was measured in the reverse direction using submitochondrial particles in skate. Transport kinetics, inhibitor response, and pH sensitivity were very similar in skate submitochondrial particle submitochondrial particles ( Km= 0.65 mmol/l, Vmax= 0.058 μmol·h−1·mg protein−1) relative to intact mitochondria. We conclude that urea influx and efflux in skate mitochondria is dependent, in part, on a bidirectional proton-sensitive mechanism similar to bacterial urea transporters and reminiscent of their ancestral origins. Rapid equilibration of urea across the mitochondrial membrane may be vital for cell osmoregulation (elasmobranch) or nitrogen waste excretion (teleost).
Blood flow responses in celiac and superior mesenteric arteries in the initial phase of digestion
Authors: Someya Nami , Endo Masako Yamaoka , Fukuba Yoshiyuki , Hayashi Naoyuki
Published: April 2008

Blood flow (BF) responses in the celiac artery (CA) and superior mesenteric artery (SMA) during and immediately after a meal are poorly understood. We characterized postprandial BF responses in these arteries in the initial phase of digestion. After a baseline measurement in the overnight fasting state, healthy subjects ingested solid food (300 kcal) and water ad libitum within 5 min (4.6 ± 0.2 min, means ± SE), and then rested for 60 min in the postprandial state. Mean blood velocities (MBVs) in CA (n = 7) and SMA ( n = 9) and mean arterial pressure (MAP) were measured throughout the procedure. The MAP was divided by the MBV to yield the resistance index (RI). The MBV in CA and SMA started increasing within a minute after beginning the meal. The MBV in CA rapidly reached its peak increase (60 ± 8% change from baseline) at 5 ± 1 min after the start of the meal, whereas the MBV in SMA gradually reached its peak increase (134 ± 14%) at 41 ± 4 min after the start of the meal, reflecting a decrease in the RI for both CA and SMA. These findings suggested an earlier increase in CA and SMA MBV, implying that the increase of BF in some parts of the small intestine precedes the arrival of chyme.
Morphine induces mesangial cell proliferation and glomerulopathy via κ-opioid receptors
Authors: Weber Marc L. , Farooqui Mariya , Nguyen Julia , Ansonoff Michael , Pintar John E. , Hebbel Robert P. , Gupta Kalpna
Published: April 2008

Morphine sulfate (MS) stimulates mesangial cell (MC) proliferation, a process central to development of glomerular disease. The purpose of this study was to examine whether specific opioid receptors (OR) and signal transducer and activators of transcription 3 (STAT3) signaling are associated with MS-induced MC proliferation. C57Bl/6J and OR-specific knockout (KO) mice were treated for up to 6 wk with PBS, MS (0.7–2.14 mg/kg), naloxone (equimolar to MS), or MS+naloxone ( n = 6 per group). Glomerular volume and expression of PCNA, Thy1, and ED1/CD68 were analyzed in kidney sections. Cell proliferation and STAT3 phosphorylation were analyzed by bromodeoxyuridine (BrdU) ELISA and Western blot, respectively, in MCs in vitro. MS treatment led to enlarged kidneys and glomerulopathy and naloxone reversed these effects. MS treatment increased glomerular volume in both μ-OR (MOR) KO and δ-OR (DOR) KO mice, but not in κ-OR (KOR) KO mice. To ascertain that MS-induced glomerulopathy in vivo was due to MC proliferation, we further examined the OR-specific effects of MS in MCs in vitro. MS-induced MC proliferation in vitro was inhibited by KOR-specific nor-BNI, but not by DOR or MOR-specific antagonists naltrindol or CTOP, respectively. KOR-specific agonist U50488H stimulated proliferation of MCs, but DOR-specific agonist DPDPE and MOR-specific agonist DAMGO did not. MS failed to stimulate proliferation of MCs from KOR KO mice. MS and KOR agonists induced STAT3 phosphorylation, and STAT3 inhibitor blocked KOR agonist-induced MC proliferation. We show that MS stimulates glomerulopathy and MC proliferation via KOR and STAT3 signaling.
Physical activity, cardiorespiratory fitness, and the metabolic syndrome in youth
Authors: Steele Rebekah M. , Brage Soren , Corder Kirsten , Wareham Nicholas J. , Ekelund Ulf
Published: March 2008

The metabolic syndrome is defined as the coexistence of multiple cardiovascular and diabetes risk factors, the prevalence of which has increased dramatically in adult populations in the last decades. More recently, the same cluster of metabolic risk factors has also been recognized in children and adolescents. Epidemiological evidence suggests that high levels of cardiorespiratory fitness (CRF) and physical activity are associated with a favorable metabolic risk profile in adults. However, in youth the role of these factors is less clear. Therefore, the purpose of this mini-review is to examine the recent evidence between objectively measured habitual physical activity and CRF with clustered metabolic risk in youth. In general, it appears that both physical activity and CRF are separately and independently associated with metabolic risk factors in youth, possibly through different causal pathways. Further research is necessary to quantify how much physical activity is needed to prevent the metabolic syndrome and the diseases with which it is associated. Public health approaches that encourage increased physical activity and reduce sedentary behaviors may prove useful in reducing the population burden associated with metabolic risk.
Airway basement membrane perimeter distensibility and airway smooth muscle area in asthma
Authors: James Alan L. , Green Francis H. , Abramson Michael J. , Bai Tony R. , Dolhnikoff Marisa , Mauad Thais , McKay Karen O. , Elliot John G.
Published: March 2008

The perimeter of the basement membrane (Pbm) of an airway viewed in cross section is used as a marker of airway size because in normal lungs it is relatively constant, despite variations in airway smooth muscle (ASM) shortening and airway collapse. In vitro studies (McParland BE, Pare PD, Johnson PR, Armour CL, Black JL. J Appl Physiol 97: 556-563, 2004; Noble PB, Sharma A, McFawn PK, Mitchell HW. J Appl Physiol 99: 2061-2066, 2005) have suggested that differential stretch of the Pbm between asthmatic and nonasthmatic airways fixed in inflation may occur and lead to an overestimation of ASM thickness in asthma. The relationships between the Pbm and the area of ASM were compared in transverse sections of airways from cases of fatal asthma (F) and from nonasthmatic control (C) cases where the lung tissue had been fixed inflated (Fi; Ci) or uninflated (Fu; Cu). When all available airways were used, the regression slopes were increased in Fu and Cu, compared with Fi and Ci, and increased in Fu and Fi, compared with Cu and Ci, suggesting effects of both inflation and asthma group, respectively. When analyses were limited to airway sizes that were available for all groups (Pbm < 15 mm), the slopes of Fi and Fu were similar, but both were greater than Ci and Cu, which were also similar. It was calculated that the effect of asthma group accounted for 80% and inflation for 20% of the differences between Fi and Ci. We conclude that the effects of inflation on the relationship between Pbm and ASM are small and do not account for the differences observed in ASM between cases of asthma and nonasthmatic controls.
Sway-dependent modulation of the triceps surae H-reflex during standing
Authors: Tokuno Craig D. , Garland S. Jayne , Carpenter Mark G. , Thorstensson Alf , Cresswell Andrew G.
Published: March 2008

Previous research has shown that changes in spinal excitability occur during the postural sway of quiet standing. In the present study, it was of interest to examine the independent effects of sway position and sway direction on the efficacy of the triceps surae Ia pathway, as reflected by the Hoffman (H)-reflex amplitude, during standing. Eighteen participants, tested under two different experimental protocols, stood quietly on a force platform. Percutaneous electrical stimulation was applied to the posterior tibial nerve when the position and direction of anteroposterior (A-P) center of pressure (COP) signal satisfied the criteria for the various experimental conditions. It was found that, regardless of sway position, a larger amplitude of the triceps surae H-reflex (difference of 9–14%; P = 0.005) occurred when subjects were swaying in the forward compared with the backward direction. The effects of sway position, independent of the sway direction, on spinal excitability exhibited a trend ( P = 0.075), with an 8.9 ± 3.7% increase in the H-reflex amplitude occurring when subjects were in a more forward position. The observed changes to the efficacy of the Ia pathway cannot be attributed to changes in stimulus intensity, as indicated by a constant M-wave amplitude, or to the small changes in the level of background electromyographic activity. One explanation for the changes in reflex excitability with respect to the postural sway of standing is that the neural modulation may be related to the small lengthening and shortening contractions occurring in the muscles of the triceps surae.
Effect of graded fructose coingestion with maltodextrin on exogenous 14C-fructose and 13C-glucose oxidation efficiency and high-intensity cycling performance
Authors: Rowlands David S. , Thorburn Megan S. , Thorp Rhys M. , Broadbent Suzanne , Shi Xiaocai
Published: March 2008

The ingestion of solutions containing carbohydrates with different intestinal transport mechanisms (e.g., fructose and glucose) produce greater carbohydrate and water absorption compared with single-carbohydrate solutions. However, the fructose-ingestion rate that results in the most efficient use of exogenous carbohydrate when glucose is ingested below absorption-oxidation saturation rates is unknown. Ten cyclists rode 2 h at 50% of peak power then performed 10 maximal sprints while ingesting solutions containing 13C-maltodextrin at 0.6 g/min combined with 14C-fructose at 0.0 (No-Fructose), 0.3 (Low-Fructose), 0.5 (Medium-Fructose), or 0.7 (High-Fructose) g/min, giving fructose:maltodextrin ratios of 0.5, 0. 8, and 1.2. Mean (percent coefficient of variation) exogenous-fructose oxidation rates during the 2-h rides were 0.18 ( 19 ), 0.27 ( 27 ), 0.36 ( 27 ) g/min in Low-Fructose, Medium-Fructose, and High-Fructose, respectively, with oxidation efficiencies (=oxidation/ingestion rate) of 62–52%. Exogenous-glucose oxidation was highest in Medium-Fructose at 0.57 ( 28 ) g/min (98% efficiency) compared with 0.54 ( 28 ), 0.48 ( 29 ), and 0.49 ( 19 ) in Low-Fructose, High-Fructose, No-Fructose, respectively; relative to No-Fructose, only the substantial 16% increase (95% confidence limits ±16%) in Medium-Fructose was clear. Total exogenous-carbohydrate oxidation was highest in Medium-Fructose at 0.84 ( 26 ) g/min. Although the effect of fructose quantity on overall sprint power was unclear, the metabolic responses were associated with lower perceptions of muscle tiredness and physical exertion, and attenuated fatigue (power slope) in the Medium-Fructose and High-Fructose conditions. With the present solutions, low-medium fructose-ingestion rates produced the most efficient use of exogenous carbohydrate, but fatigue and the perception of exercise stress and nausea are reduced with moderate-high fructose doses.
Effects of the laryngeal jet on nano- and microparticle transport and deposition in an approximate model of the upper tracheobronchial airways
Authors: Xi Jinxiang , Longest P. Worth , Martonen Ted B.
Published: April 2008

The extent to which laryngeal-induced flow features penetrate into the upper tracheobronchial (TB) airways and their related impact on particle transport and deposition are not well understood. The objective of this study was to evaluate the effects of including the laryngeal jet on the behavior and fate of inhaled aerosols in an approximate model of the upper TB region. The upper TB model was based on a simplified numerical reproduction of a replica cast geometry used in previous in vitro deposition experiments that extended to the sixth respiratory generation along some paths. Simulations with and without an approximate larynx were performed. Particle sizes ranging from 2.5 nm to 12 μm were considered using a well-tested Lagrangian tracking model. The model larynx was observed to significantly affect flow dynamics, including a laryngeal jet skewed toward the right wall of the trachea and a significant reverse flow in the left region of the trachea. Inclusion of the laryngeal model increased the tracheal deposition of nano- and micrometer particles by factors ranging from 2 to 10 and significantly reduced deposition in the first three bronchi of the model. Considering localized conditions, inclusion of the laryngeal approximation decreased deposition at the main carina and produced a maximum in local surface deposition density in the lobar-to-segmental bifurcations (G2–G3) for both 40-nm and 4-μm aerosols. These findings corroborate previous experiments and highlight the need to include a laryngeal representation in future computational and in vitro models of the TB region.
Uniqueness and Multiplicity of Solutions for a Second‐Order Discrete Boundary Value Problem with a Parameter
Authors: Liu Xi-Lan , Wu Jian-Hua
Published: April 2008

This paper is concerned with the existence of unique and multiple solutions to the boundary value problem of a second‐order difference equation with a parameter, which is a complement of the work by J. S. Yu and Z. M. Guo in 2006.
Design LDPC Codes without Cycles of Length 4 and 6
Authors: Fan Jun , Xiao Yang , Kim Kiseon
Published: April 2008

We present an approach for constructing LDPC codes without cycles of length 4 and 6. Firstly, we design 3 submatrices with different shifting functions given by the proposed schemes, then combine them into the matrix specified by the proposed approach, and, finally, expand the matrix into a desired parity‐check matrix using identity matrices and cyclic shift matrices of the identity matrices. The simulation result in AWGN channel verifies that the BER of the proposed code is close to those of Mackay′s random codes and Tanner′s QC codes, and the good BER performance of the proposed can remain at high code rates.
Suboptimal Regulation of a Class of Bilinear Interconnected Systems with Finite‐Time Sliding Planning Horizons
Authors: de la Sen M. , Garrido Aitor J. , Soto J. C. , Barambones O. , Garrido I.
Published: April 2008

This paper focuses on the suboptimization of a class of multivariable discrete‐time bilinear systems consisting of interconnected bilinear subsystems with respect to a linear quadratic optimal regulation criterion which involves the use of state weighting terms only. Conditions which ensure the controllability of the overall system are given as a previous requirement for optimization. Three transformations of variables are made on the system equations in order to implement the scheme on an equivalent linear system. This leads to an equivalent representation of the used quadratic performance index that involves the appearance of quadratic weighting terms related to both transformed input and state variables. In this way, a Riccati‐matrix sequence, allowing the synthesis of a standard feedback control law, is obtained. Finally, the proposed control scheme is tested on realistic examples.
Anxiety Related to Genetic Testing for Alpha-1 Antitrypsin Deficiency and Cystic Fibrosis in COPD and/or Bronchiectasis Patients
Authors: Coors Marilyn E. , Levinson Arnold H. , Huitt Gwen A.
Published: March 2008

Objective: To describe the psychological reaction to information about diagnostic genetic testing for α-1 antitrypsin deficiency (Alpha-1) and cystic fibrosis (CF) in chronic obstructive pulmonary disease and/or bronchiectasis patients who were tested but did not know the results. Methods: One hundred and three adults took the State-Trait Anxiety Inventory before and after a standardized educational intervention and responded to a questionnaire. Results:Information about the limitations, risks and benefits of Alpha-1 and CF testing did not raise mean anxiety levels. Mean anxiety was slightly lower after the educational intervention than at baseline (mean pretest score 35.0, posttest score 33.7; p < 0.05). Participants whose physician preinformed them of genetic testing had slightly higher mean anxiety than other participants, both before and after the intervention, but scores were comparable to those in a normative sample of general medical and surgical patients. Conclusions: Disclosure of information regarding Alpha-1 and CF testing appears to be potentially acceptable to patients and unlikely to prevent clinicians from conducting useful diagnostic procedures. This study is a step in alleviating concerns about raising issues related to genetic testing for Alpha-1 and CF in chronic obstructive pulmonary disease patients during the informed consent process.
Consumption of Folic Acid-Fortified Flour and Folate-Rich Foods among Women at Reproductive Age in South Brazil
Authors: Ferreira Ana Flávia S. , Giugliani Roberto
Published: March 2008

Objective: To evaluate the consumption of flour derivatives and folate-rich food in a sample of women at childbearing age from Porto Alegre, Brazil. Methods: Four-hundred women at childbearing age (15–45 years) were interviewed, and their socioeconomic status and folate intake were investigated. All women signed an informed consent form. Based on their dietary habits, an estimated calculation of the amount of flour intake was done. Results: Mean daily intake of folate was 220.1 µg. The intake of flour was 176 g/day/woman. The combined intake of folate from folate-rich foods and flour derivatives (wheat and/or corn flour) was 404.7 µg/day/person. Conclusion: Since the recommended daily allowance of folic acid is 400 µg/day, including both folate from food sources and supplements, the addition of folic acid to wheat flour was essential to ensure the intake of the minimum recommended amount. However, there is no guarantee that this amount was maintained on this Brazilian sample when losses resulting from cooking and/or from UV radiation (not considered in this study) are computed.
Including Deontic Reasoning as Fundamental to Theory of Mind
Authors: Wellman Henry M. , Miller Joan G.
Published: March 2008

While recognizing major contributions of the contemporary theory-of-mind framework, we identify conceptual and cultural gaps with respect to its inattention to deontic considerations. The framework has tended to portray behavior as purely self-directed, thereby neglecting everyday reasoners’ understanding of behavior as normatively based. However, in everyday reasoning, belief-desire (theory of mind) and obligation-permission (deontic) concerns interrelate. Moreover, both belief-desire reasoning and obligation-permission reasoning are early developing, universal, and inseparable in children’s understanding of persons. Thus, for both conceptual and empirical reasons, deontic and mentalistic perspectives should be seen as interdependent and integrated in understanding theory of mind.
A Family-Based Likelihood Ratio Test for General Pedigree Structures That Allows for Genotyping Error and Missing Data
Authors: Yang Yang , Wise Carol A. , Gordon Derek , Finch Stephen J.
Published: March 2008

The purpose of this work is the development of a family-based association test that allows for random genotyping errors and missing data and makes use of information on affected and unaffected pedigree members. We derive the conditional likelihood functions of the general nuclear family for the following scenarios: complete parental genotype data and no genotyping errors; only one genotyped parent and no genotyping errors; no parental genotype data and no genotyping errors; and no parental genotype data with genotyping errors. We find maximum likelihood estimates of the marker locus parameters, including the penetrances and population genotype frequencies under the null hypothesis that all penetrance values are equal and under the alternative hypothesis. We then compute the likelihood ratio test. We perform simulations to assess the adequacy of the central chi-square distribution approximation when the null hypothesis is true. We also perform simulations to compare the power of the TDT and this likelihood-based method. Finally, we apply our method to 23 SNPs genotyped in nuclear families from a recently published study of idiopathic scoliosis (IS). Our simulations suggest that this likelihood ratio test statistic follows a central chi-square distribution with 1 degree of freedom under the null hypothesis, even in the presence of missing data and genotyping errors. The power comparison shows that this likelihood ratio test is more powerful than the original TDT for the simulations considered. For the IS data, the marker rs7843033 shows the most significant evidence for our method (p = 0.0003), which is consistent with a previous report, which found rs7843033 to be the 2nd most significant TDTae p value among a set of 23 SNPs.
Estimating Relative Risks from Significant Family-Based Association Studies
Authors: Knapp Michael
Published: March 2008

Two approaches are described to estimate relative risks from significant family-based association studies. They can be used to obtain either point estimates or confidence regions. The approaches are evaluated by a simulation study and illustrated by application to a real data set. It is shown that both approaches largely reduce the bias in the relative risk estimates which can occur in case that the significant outcome of the study from which the relative risks are estimated is ignored.
FBAT-SNP-PC: An Approach for Multiple Markers and Single Trait in Family-Based Association Tests
Authors: Rakovski Cyril S. , Weiss Scott T. , Laird Nan M. , Lange Christoph
Published: March 2008

Objective: Develop a new test for family-based association studies and continuous traits that incorporates power- enhancing techniques from two existing testing strategies. Methods: The new procedure initiates with an extraction of the relevant information from the variability of the genotypes and an assessment of the approximate individual markers effects and their directions. This information is incorporated in the construction of the actual test statistic through a selection of a data-determined number of optimal linear combinations of the offspring genotypes which, in a power enhancing step, are consequently combined into a single degree of freedom test. We conduct a comparison simulation study in which the performance of the new test is contrasted with the test that is currently known to offer the highest overall power, FBAT-LC. Results: The new test has an overall performance very similar to that of FBAT-LC but attains higher power in candidate genes with lower average pairwise correlations and moderate to high allele frequencies with large gains (up to 80%) for some of the analyzed genes possessing the above-mentioned characteristics. Conclusion: The new test is a promising tool for candidate gene studies with substantial power gains for genes that are characterized by SNPs with low mean pairwise correlation.
Paranoid Psychosis and Myoclonus: Flecainide Toxicity in Renal Failure
Authors: Ting Stephen M.S. , Lee Douglas , Maclean Douglas , Sheerin Neil S.
Published: March 2008

Flecainide is a sodium channel blocker used mainly in the treatment of supraventricular arrhythmias. Central nervous system side effects such as dizziness, visual disturbances, headache and nausea are commonly associated with flecainide, but severe central nervous system toxicity is rare. We report the first case of flecainide toxicity in a patient with end-stage renal failure. Cessation of flecainide therapy resulted in a fall in serum flecainide levels, with associated resolution of adverse central nervous system effects. We also review the pharmacokinetics of flecainide in patients with chronic kidney disease.
Ryanodine Receptor-Mediated Ca2+ Events in Atrial Myocytes of Patients with Atrial Fibrillation
Authors: Liang Xin , Xie Hong , Zhu Pei-Hong , Hu Jun , Zhao Qiang , Wang Chun-Sheng , Yang Cheng
Published: March 2008

Background: Many alterations in sarcoplasmic reticulum Ca2+ handling proteins in atrial myocytes have been associated with atrial fibrillation (AF) in clinical patients, whereas the functional consequences of these alterations mostly remain unclear. Methods and Results: To know whether or not ryanodine receptor (RyR)-mediated intracellular Ca2+ events in AF atrial myocytes are affected by protein alterations, we investigated spontaneous Ca2+ sparks and Ca2+ waves in intact and permeabilized atrial myocytes of AF patients (npatients = 21) and normal sinus rhythm (NSR) patients (npatients = 22) by laser scanning confocal microscopy. It was found that the frequency, amplitude and rise time of Ca2+ sparks were comparable between AF and NSR groups, while full width and full duration at half maximum intensity significantly increased in the AF group. Along with these changes, the frequency of small and global Ca2+ waves increased in AF atrial myocytes. Conclusions: Our results clearly indicated that the spatiotemporal properties but not the frequency of Ca2+ sparks were affected in AF atrial myocytes. In addition, the frequency of Ca2+ waves increased. This profile of the alterations in RyR-mediated Ca2+ events in AF atrial myocytes was different from previous studies. The underlying mechanisms, as well as possible reasons for this discrepancy, were discussed.