bluuebunny/crossref_metadata_2025 huggingface dataset:
Inpatient Monitoring and Prognostic Importance of B‐Type Natriuretic Peptide
Authors: Aspromonte Nadia , Valle Roberto , Peacock William F. , Vanderheyden Marc , Maisel Alan
Published: March 2010

Acute decompensated heart failure (ADHF) is the leading cause of hospitalization in many industrialized countries. Despite a consistent body of data demonstrating the benefits of drug therapy, the prognosis of patients admitted with ADHF remains dismal, as it is associated with high readmission and mortality rates within 6 months after admission. ADHF is a largely hemodynamic disorder; 90% of hospitalized patients present with volume overload. Neurohormonal activation characterizes the disease; B‐type natriuretic peptide (BNP) and N‐terminal prohormone brain natriuretic peptide are natriuretic and vasodilating peptides released from the cardiac ventricles as a response to ventricular volume expansion and relate to outcome. While BNP levels obtained on admission provide independent prognostic information of in‐hospital mortality, BNP levels during and at the completion of hospitalization can help to achieve euvolemia and may reflect adequacy of treatment. Once euvolemia is reached, BNP level correlated with functional class and prognosis. Studies using natriuretic peptides have suggested that predischarge BNP level appeared to be the strongest predictor for identifying subsequent death or hospital admission at 6 months. The addition of predischarge BNP levels to a clinical/instrumental decisional score for discharge decision should make possible the detection of high‐risk patients who need reinforced treatment or follow‐up.
B‐Type Natriuretic Peptide: Application in the Community
Authors: McDonald Ken , Dahlström Ulf , Aspromonte Nadia , Jourdain Patrick , Maisel Alan , Mueller Christian , Valle Roberto
Published: March 2010

Natriuretic peptide assessment has represented a significant advance in the management of heart failure. In a syndrome in which clinical symptoms and signs can be either nonspecific or absent, the presence of a reliable biomarker to aid diagnosis, assess prognosis, and potentially guide treatment and aid in prevention of this syndrome has represented a significant advance. The following review will outline established and potential new roles for natriuretic peptide assessment in the community.
The Use of B‐Type Natriuretic Peptides in the Intensive Care Unit
Authors: Mueller Christian , Maisel Alan , Mebazaa Alexandre , Filippatos Gerasimos S.
Published: March 2010

B‐type natriuretic peptide levels are quantitative markers of cardiac stress and heart failure that summarize the extent of systolic and diastolic left ventricular dysfunction, valvular dysfunction, and right ventricular dysfunction. Initial observational pilot studies have addressed 7 potential indications in the intensive care unit: identification of cardiac dysfunction, diagnosis of hypoxic respiratory failure, risk stratification in severe sepsis and septic shock, evaluation of patients with shock, estimation of invasive measurements, weaning from mechanical ventilation, as well as perioperative and postoperative risk prediction. Although additional studies are required to better define the clinical utility of B‐type natriuretic peptide values in the intensive care unit, current data suggest that the diagnosis of hypoxic respiratory failure and timing of extubation seem to be the most promising indications.
Up‐and‐Coming Markers: Myeloperoxidase, a Novel Biomarker Test for Heart Failure and Acute Coronary Syndrome Application?
Authors: Sinning Christoph , Schnabel Renate , Peacock W. Frank , Blankenberg Stefan
Published: March 2010

Myeloperoxidase (MPO) is a mammalian enzyme responsible for generation of hypochlorite. The advantage of myeloperoxidase for use as a biomarker in the setting of heart failure and acute coronary syndrome is the early increase of MPO concentration in response to the acute event. In the setting of heart failure the reported independency of coronary artery disease and general inflammation, as indicated by MPO concentration in comparison to other inflammatory markers or in subgroups of patients with ischemic and non‐ischemic cardiomyopathy, has to be highlighted. In terms of ACS, inclusion of MPO into a multiple marker strategy might add to enhance diagnosis and therapy decision making. Therefore, MPO is a biomarker worthwhile of further evaluation in the setting of cardiovascular disease.
Cardiovascular Disease in Patients With Chronic Renal Impairment: Role of Natriuretic Peptides
Authors: Vanderheyden Marc , Bartunek Jozef , Filippatos Gerasimos , Goethals Marc , Vlem Bruno Van , Maisel Alan
Published: March 2010

Although there is overwhelming evidence that natriuretic peptides might be helpful in the diagnosis and management of congestive heart failure patients, the relationship among brain natriuretic peptides (BNP), renal function, and the severity of heart failure is less clear. It is obvious that the metabolism and elimination of BNP and N‐terminal prohormone brain natriuretic peptide (NT‐proBNP) are different with BNP clearance less dependent upon renal function. This paper reviews current data about the diagnostic and predictive role of natriuretic peptides to detect cardiac events in patients with chronic kidney disease. Although BNP and Nt‐proBNP can be used to diagnose acute heart failure and may help predict risk and future cardiac events in patients with chronic kidney disease (CKD), a strategy that incorporates their use in daily clinical practice is still lacking.
Usefulness of Serial Assessment of Natriuretic Peptides in the Emergency Department for Patients With Acute Decompensated Heart Failure
Authors: DiSomma Salvatore , Magrini Laura , Pittoni Valerio , Marino Rossella , Peacock W. Frank , Maisel Alan
Published: March 2010

The value of natriuretic peptides, both B‐type natriuretic peptide (BNP) and N‐terminal prohormone brain natriuretic peptide (NTproBNP), for determining diagnosis, severity, and prognosis of emergency department (ED) patients with acute decompensated heart failure (ADHF) has been well documented. Emerging data support the hypothesis that repeated natriuretic peptide determinations in the acute phase of ADHF may assist in confirming the diagnosis, monitoring drug therapy, and evaluating the adequacy of patient stabilization. Data from the authors' group demonstrate that in patients admitted to the ED for acute dyspnea, serial NTproBNP measurement at admission and 4, 12, and 24 hours later was useful in confirming the diagnosis of ADHF compared with patients with chronic obstructive pulmonary disease. Moreover, in the same patients receiving intensive intravenous diuretic therapy, there was a progressive reduction of NTproBNP blood levels from hospitalization to discharge (P<.001), accompanied by clinical improvement and stabilization of heart failure. More recently, the authors also demonstrated that in ADHF patients improving with diuretics, a progressive reduction in BNP levels was observed, starting 24 hours after ED admission and continuing until discharge. Comparing BNP and NTproBNP, there was a significant correlation between NTproBNP and BNP levels but not between NTproBNP's and BNP's percent variation compared with baseline. In ADHF, serial ED measurements of BNP are useful for monitoring the effects of treatment. A reduction in BNP from admission to discharge is indicative of clinical improvement.
Protecting River Corridors in Vermont1
Authors: Kline Michael , Cahoon Barry
Published: March 2010

Kline, Michael and Barry Cahoon, 2010. Protecting River Corridors in Vermont. Journal of the American Water Resources Association (JAWRA) 46(2):227‐236. DOI: 10.1111/j.1752‐1688.2010.00417.x

Abstract:  The Vermont Agency of Natural Resources’ current strategy for restoring aquatic habitat, water quality, and riparian ecosystem services is the protection of fluvial geomorphic‐based river corridors and associated wetland and floodplain attributes and functions. Vermont has assessed over 1,350 miles of stream channels to determine how natural processes have been modified by channel management activities, corridor encroachments, and land use/land cover changes. Nearly three quarters of Vermont field‐assessed reaches are incised limiting access to floodplains and thus reducing important ecosystem services such as flood and erosion hazard mitigation, sediment storage, and nutrient uptake. River corridor planning is conducted with geomorphic data to identify opportunities and constraints to mitigating the effects of physical stressors. Corridors are sized based on the meander belt width and assigned a sensitivity rating based on the likelihood of channel adjustment due to stressors. The approach adopted by Vermont is fundamentally based on restoring fluvial processes associated with dynamic equilibrium, and associated habitat features. Managing toward fluvial equilibrium is taking hold across Vermont through adoption of municipal fluvial erosion hazard zoning and purchase of river corridor easements, or local channel and floodplain management rights. These tools signify a shift away from primarily active management approaches of varying success that largely worked against natural river form and process, to a current community‐based, primarily passive approach to accommodate floodplain reestablishment through fluvial processes.
Groundwater Denitrification Capacity of Riparian Zones in Suburban and Agricultural Watersheds1
Authors: Watson Tara K. , Kellogg Dorothy Q. , Addy Kelly , Gold Arthur J. , Stolt Mark H. , Donohue Sean W. , Groffman Peter M.
Published: March 2010

Watson, Tara K., Dorothy Q. Kellogg, Kelly Addy, Arthur J. Gold, Mark H. Stolt, Sean W. Donohue, and Peter M. Groffman, 2010. Groundwater Denitrification Capacity of Riparian Zones in Suburban and Agricultural Watersheds. Journal of the American Water Resources Association (JAWRA) 46(2):237‐245. DOI: 10.1111/j.1752‐1688.2010.00418.x

Abstract:  We evaluated the relationship of dominant watershed land use to the structure and nitrogen (N) sink function of riparian zones. We focused on groundwater denitrification capacity, water table dynamics, and the presence and pattern of organically enriched deposits. We used the push‐pull method (measurement of 15N‐enriched denitrification gases derived from an introduced groundwater plume of 15N‐enriched nitrate) to evaluate groundwater denitrification capacity on nine forested wetland riparian sites developed in alluvial or outwash parent materials in southern New England. Three replicate sites were located in each of the three watershed types, those with substantial (1) irrigated agriculture, (2) suburban development, and (3) forest. Soil morphology and water table dynamics were assessed at each site. We found significantly lower mean annual water tables at sites within watersheds with substantial irrigated agriculture or suburban development than forested watersheds. Water table dynamics were more variable at sites within suburban watersheds, especially during the summer. Groundwater denitrification capacity was significantly greater at sites within forested watersheds than in watersheds with substantial irrigated agriculture. Because of the high degree of variability observed in riparian sites within suburban watersheds, groundwater denitrification capacity was not significantly different from either forested or agricultural watersheds. The highly variable patterns of organically enriched deposits and water tables at sites within suburban watersheds suggests that depositional events are irregular, limiting the predictability of groundwater N dynamics in these riparian zones. The variability of riparian N removal in watersheds with extensive suburbia or irrigated agriculture argues for N management strategies emphasizing effective N source controls in these settings.
Hot Spots and Hot Moments in Riparian Zones: Potential for Improved Water Quality Management1
Authors: Vidon Philippe , Allan Craig , Burns Douglas , Duval Tim P. , Gurwick Noel , Inamdar Shreeram , Lowrance Richard , Okay Judy , Scott Durelle , Sebestyen Steve
Published: March 2010

Vidon, Philippe, Craig Allan, Douglas Burns, Tim P. Duval, Noel Gurwick, Shreeram Inamdar, Richard Lowrance, Judy Okay, Durelle Scott, and Steve Sebestyen, 2010. Hot Spots and Hot Moments in Riparian Zones: Potential for Improved Water Quality Management. Journal of the American Water Resources Association (JAWRA) 46(2):278‐298. DOI: 10.1111/j.1752‐1688.2010.00420.x

Abstract:  Biogeochemical and hydrological processes in riparian zones regulate contaminant movement to receiving waters and often mitigate the impact of upland sources of contaminants on water quality. These heterogeneous processes have recently been conceptualized as “hot spots and moments” of retention, degradation, or production. Nevertheless, studies investigating the importance of hot phenomena (spots and moments) in riparian zones have thus far largely focused on nitrogen (N) despite compelling evidence that a variety of elements, chemicals, and particulate contaminant cycles are subject to the influence of both biogeochemical and transport hot spots and moments. In addition to N, this review summarizes current knowledge for phosphorus, organic matter, pesticides, and mercury across riparian zones, identifies variables controlling the occurrence and magnitude of hot phenomena in riparian zones for these contaminants, and discusses the implications for riparian zone management of recognizing the importance of hot phenomena in annual solute budgets at the watershed scale. Examples are presented to show that biogeochemical process‐driven hot spots and moments occur along the stream/riparian zone/upland interface for a wide variety of constituents. A basic understanding of the possible co‐occurrence of hot spots and moments for a variety of contaminants in riparian systems will increase our understanding of the influence of riparian zones on water quality and guide management strategies to enhance nutrient or pollutant removal at the landscape scale.
Antidiabetic activity of the mangrove speciesCeriops decandrain alloxan‐induced diabetic rats
Authors: NABEEL Mannalamkunnath Alikunhi , KATHIRESAN Kandasamy , MANIVANNAN Subramanian
Published: March 2010

Background: Diabetes is a series of disorders characterized by increased fasting and postprandial glucose concentration and insulin deficiency and/or decreased insulin action. Although there are a number of commercially available drugs for the treatment of diabetes, their long‐term use may cause unwanted side effects. Consequently, many studies are underway to find natural remedies that can effectively reduce the intensity of diabetes. The aim of the present study was to evaluate the antidiabetic activity of the mangrove speciesCeriops decandra.

Methods: The effects of daily oral administration of an ethanolic extract from the leaves ofC. decandra(30, 60, 120 mg/kg) for 30 days on blood glucose, hemoglobin (Hb), HbA1c, liver glycogen and some carbohydrate metabolic enzymes were evaluated in normal and alloxan‐induced diabetic rats. The effects of these extracts were compared with the effect of 30‐days treatment with 0.1 mg/kg, p.o., glibenclamide, a commercially available drug commonly used in the treatment of diabetes.

Results: Oral administration of 120 mg/kg extract modulated all the parameters evaluated to levels seen in control rats. The effects of 120 mg/kg extract were comparable to those of glibenclamide.

Conclusion: The extract of the mangrove plantC. decandraexhibited promising antidiabetic activity and could be considered for further evaluation in clinical studies and drug development.
Measurement of HbA1c from stored whole blood samples in the Atherosclerosis Risk in Communities study
Authors: SELVIN Elizabeth , CORESH Josef , ZHU Hong , FOLSOM Aaron , STEFFES Michael W.
Published: March 2010

Background:  The aims of the present study were to demonstrate the reliability of HbA1c measurements during two time periods and to compare these measurements with HbA1c distribution in the general US population.

Methods:  HbA1c was measured in 14 069 whole blood samples in the Atherosclerosis Risk in Communities (ARIC) study using different HPLC instruments across two time periods, namely 2003–2004 and 2007–2008. At the time of measurement, samples had been in storage at −70°C for up to 18 years. To assess differences in values, HbA1c measurements were repeated in 383 samples at both periods. Indirect comparisons were made by comparing our measurements against those from a nationally representative study.

Results:  The coefficients of variation for quality control samples were 1.8% (n = 89) in 2003–2004 and 1.4% (n = 259) in 2007–2008. The correlation between measurements at the two time points was high (r = 0.99), but with a slight bias: 0.29% points higher in 2007–2008 vs 2003–2004 (n = 383; P < 0.0001). The comparison yielded the following Deming regression equation: y(2007–2008) = 0.073 + 1.034x(2003–2004). After alignment using this equation, the distribution of HbA1c in the ARIC study was similar to that in the national study using fresh samples.

Conclusions:  Measurements of HbA1c from samples stored for up to 18 years are highly reliable when using state‐of‐the‐art HPLC instruments, but with some bias introduced over time. The HbA1c data now available in the ARIC study should be invaluable for investigations into the clinical utility of HbA1c as a diagnostic test for diabetes.
An open source chimera checker for the fungal ITS region
Authors: NILSSON R. H. , ABARENKOV KESSY , VELDRE VILMAR , NYLINDER STEPHAN , DE WIT PIERRE , BROSCHÉ SARA , ALFREDSSON JOHAN F. , RYBERG MARTIN , KRISTIANSSON ERIK
Published: March 2010

The internal transcribed spacer (ITS) region of the nuclear ribosomal repeat unit holds a central position in the pursuit of the taxonomic affiliation of fungi recovered through environmental sampling. Newly generated fungal ITS sequences are typically compared against the International Nucleotide Sequence Databases for a species or genus name using the sequence similarity software suite blast. Such searches are not without complications however, and one of them is the presence of chimeric entries among the query or reference sequences. Chimeras are artificial sequences, generated unintentionally during the polymerase chain reaction step, that feature sequence data from two (or possibly more) distinct species. Available software solutions for chimera control do not readily target the fungal ITS region, but the present study introduces a blast‐based open source software package (available at http://www.emerencia.org/chimerachecker.html) to examine newly generated fungal ITS sequences for the presence of potentially chimeric elements in batch mode. We used the software package on a random set of 12 300 environmental fungal ITS sequences in the public sequence databases and found 1.5% of the entries to be chimeric at the ordinal level after manual verification of the results. The proportion of chimeras in the sequence databases can be hypothesized to increase as emerging sequencing technologies drawing from pooled DNA samples are becoming important tools in molecular ecology research.
Foot deformities in patients with rheumatoid arthritis: the relationship with foot functions
Authors: GÖKSEL KARATEPE Altınay , GÜNAYDIN Rezzan , ADIBELLI Zehra Hilal , KAYA Taciser , DURUÖZ Evrim
Published: March 2010

Aim:  The aim of this study was to investigate foot deformities in patients with rheumatoid arthritis (RA), to detect frequency of deformities and to assess the relationship between foot deformities and foot functions.

Methods:  Anteroposterior and lateral radiographs of 40 patients and 40 control subjects were studied. The hallux valgus (HV) angle, intermetatarsal angle between first and second metatarsals, intermetatarsal angle between first and fifth metatarsals, and calcaneal pitch were measured on radiographs. Foot functions were measured by the Foot and Ankle Outcome Score (FAOS).

Results:  The frequency of foot deformities in RA patients was determined as 78.8%. The most frequent foot deformity in RA patients was HV (62.5%), followed by metatarsus primus varus (MPV) (41.3%). MPV and splaying of the forefoot deformities were significantly more frequent in RA patients than the control group (P < 0.05). Mild to moderate effect on FAOS subscales was observed in RA patients. There was a slight, but significant correlation between the foot deformities and the FAOS subscales except for quality of life subscale.

Conclusions:  In this study, it has been shown that foot deformities are frequent in patients with RA and that there is slight deterioration in foot functions related to RA. Our results indicated that foot deformities have small, but clinically important changes on foot functions. There is a need for more studies, which evaluates the foot deformities, to further explore the relationship between the foot deformities and foot function in patients with RA.
Live polio vaccine exposure while receiving anti‐TNF therapy for reactive arthritis
Authors: BADSHA Humeira , DAHER Mirna , EDWARDS Christopher J.
Published: March 2010

International guidelines state that live vaccines are contraindicated in patients on anti‐TNF therapy. However, we report the experience of a patient who inadvertently received live polio vaccine whilst receiving anti‐TNF therapy. Patient did not suffer from any infectious sequel as a result. No clear guidelines are available for all vaccines in patients with specific rheumatic diseases. However, if we consider adult patients with rheumatic diseases to have altered immunocompetence, it is recommended that they receive the usual inactivated vaccines according to standard schedules, and live vaccines should be avoided in those who are treated with more potent forms of immune suppression. Patients should be counseled regarding the risks of live vaccines prior to treatment with anti‐TNF therapy.
Combination therapy of miglitol and insulin in type 1 diabetes mellitus patients
Authors: Kubo Sayaka , Watada Hirotaka , Kawamori Ryuzo
Published: March 2010

Aims/Introduction:  Patients with type 1 diabetes mellitus often show a precipitous postprandial rise in blood glucose that cannot be controlled, even by intensive insulin therapy. The combined use of an α‐glucosidase inhibitor with insulin seems to be highly beneficial in such cases.

Materials and Methods:  We investigated the efficacy and safety of miglitol, an α‐glucosidase inhibitor, for 12 weeks in 43 type 1 diabetes patients on intensive insulin therapy.

Results:  Co‐administration of miglitol resulted in only a modest and temporal decrease in HbA1c level. However, it resulted in a significant reduction of plasma glucose level after breakfast (250.7 ± 102.0 mg/dL at 2 h after breakfast before treatment; 212.0 ± 95.8 mg/dL at 2 h after breakfast after treatment for 12 weeks, P = 0.01) and a significant reduction of insulin dosage (41.6 ± 17.1 U/day before treatment; 39.8 ± 17.4 U/day 12 weeks after treatment, P < 0.001). During the study period, 88.4% (38/43) of subjects experienced hypoglycemia, but all events were mild except for one case, which was considered to be moderate. No unexpected adverse events were observed during the study period.

Conclusions:  Co‐administration of miglitol in type 1 diabetes patients on intensive insulin therapy resulted in an improvement of postprandial hyperglycemia with the reduction of insulin dosage. Considering the importance of postprandial hyperglycemia in the onset of cardiovascular disease, the combination therapy of miglitol and insulin could be advantageous in type 1 diabetes mellitus patients.
Experimental Investigation of Static Interfacial Fracture in Orthotropic Polymer Composite Bimaterials Using Photoelasticity
Authors: Ellingsen Marius D. , Khanna Sanjeev K.
Published: March 2010

The effects of static Mode I (opening mode) loading on orthotropic-orthotropic bimaterial interface cracks have been investigated using the experimental technique of transmission photoelasticity. For successful implementation of this experimental technique transparent and birefringent glass fiber reinforced polyester composite materials were developed, enabling the direct observation and recording of photoelastic fringes in the vicinity of the interface crack in the orthotropic bimaterial. It is our belief that this is the first of such experimental investigation. Opening and shearing mode stress-intensity factors and the strain energy release rates have been calculated for various combinations of the bimaterial halves. Results have been verified by mathematically regenerating the observed isochromatic fringe patterns. This study has made it feasible to investigate interfacial fracture in orthotropic-orthotropic bimaterials and orthotropic-isotropic bimaterials using photoelasticity.
Micromechanics Study of Fatigue Damage Incubation Following an Initial Overstrain
Authors: Xue Yibin , Wright Amanda M. , McDowell David L. , Horstemeyer Mark F. , Solanki Kiran , Hammi Youssef
Published: March 2010

Understanding and quantifying the effects of overloads/overstrains on the cyclic damage accumulation at a microscale discontinuity is essential for the development of a multistage fatigue model under variable amplitude loading. Micromechanical simulations are conducted on a 7075-T651 Al alloy to quantify the cyclic microplasticity in the matrix adjacent to intact or cracked, life-limiting intermetallic particles. An initial overstrain followed by constant amplitude cyclic straining is simulated considering minimum to maximum strain ratios of 0 and −1. The nonlocal equivalent plastic strain at the cracked intermetallic particles reveals overload effects manifested in two forms: (1) the cyclic plastic shear strain range is greater in the cycles following an initial tensile overstrain than without the overstrain and (2) the initial overstrain causes the nonlocal cumulative equivalent plastic strain to double in subsequent tensile-going half cycles and triple in subsequent compressive-going half cycles, as compared with cases without an initial tensile overstrain. The cyclic plastic zone at the microdiscontinuity corresponds to that of the maximum strain during the initial overstrain and the nonlocal cyclic plastic shear strain range in the matrix near the intact or cracked inclusion is substantially increased for the same remote strain amplitude relative to the case without initial overstrain. These results differ completely from the effects of initial tensile overload on the response at a macroscopic notch root or at the tip of a long fatigue crack in which the driving forces for crack formation or growth, respectively, are reduced. The micromechanical simulation results support the incorporation of enhanced cyclic microplasticity and driving force to form fatigue cracks at cracked inclusions following an initial tensile overstrain in a fatigue incubation model.
Molecular Dynamics Simulations of Carbon Nanotube Interactions in Water/Surfactant Systems
Authors: Uddin Nasir M. , Capaldi Franco , Farouk Bakhtier
Published: March 2010

The properties of nanocomposite materials depend on the dispersion of the nanoparticles/nanofibers within the matrix. The addition of surfactants and varied processing techniques are used to increase the dispersion of the nanoparticles in the final composite. A method for the quantitative prediction of the interactions between nanoparticles in solution would aid in the design of processing schedules. In this study, molecular dynamics simulations are used to compute for the potential of mean force as a function of the distance and orientation between a pair of single-walled carbon nanotubes (CNTs) in water. An adaptive biasing force method is used to speed up the calculations. Simulation results show that CNT orientation and the addition of surfactant can significantly affect CNT interactions and inturn dispersion.
Damage and Rupture Simulation for Mechanical Parts Under Cyclic Loadings
Authors: Bogard Fabien , Lestriez Philippe , Guo Ying-Qiao
Published: March 2010

The purpose of this study is to develop a numerical methodology to simulate the fatigue damage of revolving mechanical parts under cyclic loadings (such as rolling bearings). The methodology is based on the continuum damage mechanics and on a fatigue damage model. The fatigue damage can be caused by numerous loading cycles, even in an elastic state; the damage will then influence the elastoplastic behaviors. The coupling effect of both enfeebles the material strength and leads to the rupture. An important improvement on the Sines fatigue criterion is proposed, which allows the coupling behaviors of damage and plasticity to be described better. This paper deals with the following aspects: (i) the fatigue damage model and the identification of fatigue parameters using S-N curves; (ii) the elastoplastic constitutive behaviors coupled with the fatigue damage; (iii) a cycle jumping algorithm to reduce the computation time; and (iv) an adaptative remeshing to follow the rupture propagation. These mechanical and numerical models are implemented in the framework of ABAQUS software. Two applications are presented in this paper: the fatigue lifetime prediction for a cyclic tension specimen and the fatigue spalling (or chipping) initiation and growth in a thrust roller bearing under a cyclic loading. The present approach is very efficient and helpful for the lifetime prediction of revolving mechanical components.
The Effect of Applied Forging Pressure on Primary Structure Deformation in Rheology Forging Process With Solid Fraction Controlled A356 and AA2024 Alloys
Authors: Lee S. M. , Kim H. H. , Kang C. G.
Published: March 2010

Mechanical properties and microstructure of heat-treated samples of A356 and AA2024 aluminum alloys, which were rheoforged by varying the change in pressure and temperature were investigated, preventing defects such as porosity, liquid segregation, and insufficient filling occurring during rheoforging process. The rheology material was fabricated by an electromagnetic stirring process by controlling stirring current so that shearing force and temperature of the molten metal were controlled during electromagnetic stirring. As a result, by crushing dendrite and rosette type microstructures, fine and globularized rheology material was obtained and the feasibility of the rheoforging process was found to be positive. In the case of the direct rheoforging process, excessive applied forging-pressure caused material spattering, which in turn caused eutectic segregation. This segregation brought about a shrink hole and thus led to a deterioration of mechanical strength. According to varied applied forging pressures, agglomeration phenomena of primary particles of wrought aluminum alloy remarkably increased as compared with an as-cast aluminum alloy.
A New Multiaxial Fatigue Life Prediction Model Under Proportional and Nonproportional Loading
Authors: Li Jing , Sun Qiang , Zhang Zhong-Ping , Li Chun-Wang , Zhang Dong-Wei
Published: March 2010

Based on the critical plane approach, the drawbacks of the Wang–Brown (WB) model are analyzed. It is discovered that the normal strain excursion in the WB model cannot account for the additional cyclic hardening well. In order to solve this problem, a new damage parameter for multiaxial fatigue is proposed. In the meantime, the procedure for multiaxial fatigue life assessment incorporating critical plane damage model is presented as well. In the new damage parameter, both strain and stress components are considered, and the effect of the additional cyclic hardening on the fatigue life during nonproportional loading is taken into account as well. In addition, the proposed model is modified when the mean stress is existence. It is convenient for engineering application because of no material constants in this parameter. The capability of fatigue life assessment for the proposed fatigue damage model is checked against the experimental data found in literature for tubular specimens of 1045HR steel, hot-rolled 45 steel, S460N steel, GH4169 alloy at elevated temperature, and the notched shaft of SAE 1045 steel, which is under cyclic bending and torsion loading. It is demonstrated that the proposed criterion gives satisfactory results for all the five checked materials.
Molecular dynamics simulations of aqueous solutions of ionic liquids
Authors: Matas Karel , Kolafa Jiří
Published: March 2010

We performed a molecular dynamics study of aqueous solutions of ionic liquids 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) and 1-octyl-3-methylimidazolium chloride ([OMIM]Cl) in order to elucidate the anomalous dependence of the surface tension on concentration. We found that cations are placed preferably at the surface with alkyl chains pointing towards vacuum. Anions compensate the surplus of a positive charge on the surface by forming a layer below the cation layer. At lower concentrations the surface tension decreases with concentration. At higher concentrations the surface becomes saturated by cations and the decrease slows down. The decrease of surface tension with concentration is a consequence of the structural changes, although the experimentally observed anomalous increase at even higher concentrations was not reproduced.
Factors associated with self-reported risk-taking behaviour on ski slopes
Authors: Ruedl G , Pocecco E , Sommersacher R , Gatterer H , Kopp M , Nachbauer W , Burtscher M
Published: March 2010

Background

In recent years, discussions have arisen about the potential influence of wearing a ski helmet on an increasing level of risk taking and higher speeds on ski slopes.

Objective

To evaluate factors associated with selfreported risk-taking behaviour in recreational skiers and snowboarders.

Methods

Speeds of skiers and snowboarders were measured with a radar speed gun and sex, age, nationality, height, weight and helmet use, used type of gear, self-estimated skill level and self-estimated fitness level were recorded. In addition, participants were asked if they considered themselves as cautious or risk-taking skier or snowboarder.

Results

In total, 453 skiers (39.6 (14.8) years) and 74 snowboarders (26.4 (9.6) years) have been interviewed. A stepwise forward logistic regression model revealed five independent factors for a risk-taking behaviour on slopes. Adjusted OR and their 95% CI showed that risk takers were <40 years (OR 2.4, 95% CI 1.51 to 3.80), had a higher skill level (OR 2.1, 95% CI 1.25 to 3.50), were more likely males (OR 2.0, 95% CI 1.22 to 3.26), had a lower body mass index (22.8 vs 24.2) and skied with higher speeds (on average 53 vs 45 km/h) compared to cautious skiers.

Conclusion

Risk-taking behaviour on ski slopes is associated with younger age, higher skiing ability, male sex, lower body mass index and on average higher speeds. Helmet use is not associated with riskier behaviour on slopes. In addition, helmet use has to be recommended because helmet use reduces the risk of head injuries among skiers and snowboarders.
Technology in Paralympic sport: performance enhancement or essential for performance?
Authors: Burkett Brendan
Published: March 2010

Background

People with disabilities often depend on assistive devices to enable activities of daily living as well as to compete in sport. Technological developments in sport can be controversial.

Objectives

To review, identify and describe current technological developments in assistive devices used in the summer Paralympic Games; and to prepare for the London 2012 Games, the future challenges and the role of technology are debated.

Methods

A systematic review of the peer-reviewed literature and personal observations of technological developments at the Athens (2004) and Beijing (2008) Paralympic Games was conducted.

Results

Standard assistive devices can inhibit the Paralympians’ abilities to perform the strenuous activities of their sports. Although many Paralympic sports only require technology similar to their Olympic counterparts, several unique technological modifications have been made in prosthetic and wheelchair devices. Technology is essential for the Paralympic athlete, and the potential technological advantage for a Paralympian, when competing against an Olympian, is unclear.

Conclusion

Technology must match the individual requirements of the athlete with the sport in order for Paralympians to safely maximise their performance. Within the ‘performance enhancement or essential for performance?’ debate, any potential increase in mechanical performance from an assistive device must be considered holistically with the compensatory consequences the disability creates. To avoid potential technology controversies at the 2012 London Olympic and Paralympic Games, the role of technology in sport must be clarified.
Thermodynamic Studies of the Arsenic Adsorption on Iron Species Generated by Electrocoagulation
Authors: Parga J. R. , Vazquez V. , Moreno H.
Published: March 2010

Protection of global environment and sustainable sources of clean water are a necessity for human survival. The wide use of heavy metals by modern industries has generated heavy metals containing wastes and by-products. Specifically, large quantities of arsenic compounds are being discharged into the environment. The full potential of Electrocoagulation (EC) with air injection as an alternative wastewater treatment technique to remove arsenic from water showed more than 99 percent of removal without adding any chemicals. This study has been carried out to determine the feasibility of arsenic adsorption on iron species by EC process using the Langmuir’s Isotherm. Thermodynamic parameters such as ΔH°, ΔS°, and ΔG° were calculated. It was found that the adsorption process is exothermic and spontaneous. Some experiments were conducted to determine the optimum operating conditions such as current density, pH, and residence time. Also in this study, X-Ray Diffraction, Scanning Electron Microscopy, Mössbauer Spectroscopy, and Fourier Transform infrared spectroscopy were used to characterize the EC solid products that revealed the expected crystalline iron oxides (lepidocrocite, magnetite, gohetite, and iron oxide).
Recent Advances and Future Challenges for Artificial Neural Systems in Geotechnical Engineering Applications
Authors: Shahin Mohamed A. , Jaksa Mark B. , Maier Holger R.
Published: March 2010

Artificial neural networks (ANNs) are a form of artificial intelligence that has proved to provide a high level of competency in solving many complex engineering problems that are beyond the computational capability of classical mathematics and traditional procedures. In particular, ANNs have been applied successfully to almost all aspects of geotechnical engineering problems. Despite the increasing number and diversity of ANN applications in geotechnical engineering, the contents of reported applications indicate that the progress in ANN development and procedures is marginal and not moving forward since the mid‐1990s. This paper presents a brief overview of ANN applications in geotechnical engineering, briefly provides an overview of the operation of ANN modeling, investigates the current research directions of ANNs in geotechnical engineering, and discusses some ANN modeling issues that need further attention in the future, including model robustness; transparency and knowledge extraction; extrapolation; uncertainty.
Simulation of Supersonic Flow in an Ejector Diffuser Using the JPVM
Authors: Couder-Castañeda Carlos
Published: March 2010

The ejectors are used commonly to extract gases in the petroleum industry where it is not possible to use an electric bomb due the explosion risk because the gases are flammable. The steam ejector is important in
creating and holding a vacuum system. The goal of this job is to develop an object oriented parallel numerical code to investigate the unsteady behavior of the supersonic flow in the ejector diffuser to have an efficient computational tool that allows modeling different diffuser designs. The first step is the construction of a proper transformation of the solution space to generate a computational regular space to apply an explicit scheme. The second step, consists in developing the numerical code with an‐object‐oriented parallel methodology. Finally, the results obtained about the flux are satisfactory compared with the physical sensors, and the parallel paradigm used not only reduces the computational time but also shows a better maintainability, reusability, and extensibility accuracy of the code.
Nanoencapsulation of Nimodipine in Novel Biocompatible Poly(propylene‐co‐butylene succinate) Aliphatic Copolyesters for Sustained Release
Authors: Papadimitriou Sofia , Papageorgiou George Z. , Kanaze Feras I. , Georgarakis Manolis , Bikiaris Dimitrios N.
Published: March 2010

Biocompatible poly(propylene‐co‐butylene succinate) (PPBSu) copolyesters, containing up to 50 mol% butylene succinate units, were synthesized by the two‐stage melt polycondensation method (esterification and polycondensation). The copolymers were fully characterized and biocompatibility studies were also performed. They were proved to be biocompatible and they were used as polymer matrices for the preparation of drug loaded nanoparticles. Nimodipine was selected as a model hydrophobic poorly water soluble drug. From the results obtained by dynamic light scattering (DLS) and scanning electron microscopy (SEM), drug loaded copolymer nanoparticles were found to exhibit a spherical shape and their mean diameter appeared in the range of 180–200 nm. Fourier Transformation‐Infrared Spectroscopy (FTIR) spectra indicated that no chemical interaction between the drug and the matrix could be justified, while Wide‐Angle X‐Ray Diffraction (WAXD) patterns proved a low degree of crystallinity of Nimodipine in the nanoparticles. The release behavior of the model drug from nanoparticles was also investigated in order to identify modifications and find out any possible correlation between the chemical composition of the polymer matrix and the drug release rates.
Nonsphericity of the Moon and Near Sun‐Synchronous Polar Lunar Orbits
Authors: Carvalho Jean Paulo dos Santos , de Moraes Rodolpho Vilhena , de Almeida Prado Antônio Fernando Bertachini
Published: March 2010

Herein, we consider the problem of a lunar artificial satellite perturbed by the nonuniform distribution of mass of the Moon taking into account the oblateness (J2) and the equatorial ellipticity (sectorial term C22). Using Lie‐Hori method up to the second order short‐period terms of the Hamiltonian are eliminated. A study is done for the critical inclination in first and second order of the disturbing potential. Coupling terms due to the nonuniform distribution of mass of the Moon are analyzed. Numerical simulations are presented with the disturbing potential of first and second order is. It an approach for the behavior of the longitude of the ascending node of a near Sun‐synchronous polar lunar orbit is presented.
Assessing the Quality of Whole Genome Alignments in Bacteria
Authors: Swidan Firas , Shamir Ron
Published: March 2010

Comparing genomes is an essential preliminary step to solve many problems in biology. Matching long similar segments between two genomes is a precondition for their evolutionary, genetic, and genome rearrangement analyses. Though various comparison methods have been developed in recent years, a quantitative assessment of their performance is lacking. Here, we describe two families of assessment measures whose purpose is to evaluate bacteria-oriented comparison tools. The first measure is based on how well the genome segmentation fits the gene annotation of the studied organisms; the second uses the number of segments created by the segmentation and the percentage of the two genomes that are conserved. The effectiveness of the two measures is demonstrated by applying them to the results of genome comparison tools obtained on 41 pairs of bacterial species. Despite the difference in the nature of the two types of measurements, both show consistent results, providing insights into the subtle differences between the mapping tools.
Activation of Cyclin‐Dependent Kinase 5 Is a Consequence of Cell Death
Authors: Ye Yixia , Tinari Antonella , Malorni Walter , Lockshin Richard A. , Zakeri Zahra
Published: March 2010

Cyclin‐dependent kinase 5 (Cdk5) is similar to other Cdks but is activated during cell differentiation and cell death rather than cell division. Since activation of Cdk5 has been reported in many situations leading to cell death, we attempted to determine if it was required for any form of cell death. We found that Cdk5 is activated during apoptotic deaths and that the activation can be detected even when the cells continue to secondary necrosis. This activation can occur in the absence of Bim, calpain, or neutral cathepsins. The kinase is typically activated by p25, derived from p35 by calpain‐mediated cleavage, but inhibition of calpain does not affect cell death or the activation of Cdk5. Likewise, RNAi‐forced suppression of the synthesis of Cdk5 does not affect the incidence or kinetics of cell death. We conclude that Cdk5 is activated as a consequence of metabolic changes that are common to many forms of cell death. Thus its activation suggests processes during cell death that will be interesting or important to understand, but activation of Cdk5 is not necessary for cells to die.
A Bark Thickness Model for White Spruce in Alaska Northern Forests
Authors: Malone Thomas , Liang Jingjing
Published: March 2010

Here we developed a simple linear model to estimate white spruce bark thickness in the northern forests of Alaska. Data were collected from six areas throughout interior and southcentral Alaska. Geographic variation of bark thickness was tested between the Alaska statewide model and for each geographic area. The results show that the Alaska statewide model is accurate, simple, and robust, and has no practical geographic variation over the six areas. The model provides accurate estimates of the bark thickness for white spruce trees in Alaska for a wide array of future studies, and it is in demand by landowners and forest managers to support their management decisions.
Comparative Analyses of Transcriptional Profiles in Mouse Organs Using a Pneumonic Plague Model after Infection with Wild-TypeYersinia pestisCO92 and Its Braun Lipoprotein Mutant
Authors: Galindo Cristi L. , Moen Scott T. , Kozlova Elena V. , Sha Jian , Garner Harold R. , Agar Stacy L. , Chopra Ashok K.
Published: March 2010

We employed Murine GeneChips to delineate the global transcriptional profiles of the livers, lungs, and spleens in a mouse pneumonic plague infection model with wild-type (WT)Y. pestisCO92 and its Braun lipoprotein (Δlpp) mutant with reduced virulence. These organs showed differential transcriptional responses to infection with WTY. pestis, but the overall host functional processes affected were similar across all three tissues. Gene expression alterations were found in inflammation, cytokine signaling, and apoptotic cell death-associated genes. Comparison of WT andΔlppmutant-infected mice indicated significant overlap in lipopolysaccharide- (LPS-) associated gene expression, but the absence of Lpp perturbed host cell signaling at critical regulatory junctions resulting in altered immune response and possibly host cell apoptosis. We generated a putative signaling pathway including major inflammatory components that could account for the synergistic action of LPS and Lpp and provided the mechanistic basis of attenuation caused by deletion of thelppgene fromY. pestisin a mouse model of pneumonic plague.
Convex Solutions of a Nonlinear Integral Equation of Urysohn Type
Authors: Trif Tiberiu
Published: March 2010

We study the solvability of a nonlinear integral equation of Urysohn type. Using the technique of measures of noncompactness we prove that under certain assumptions this equation possesses solutions that are convex of order "Equation missing" for each "Equation missing", with "Equation missing" being a given integer. A concrete application of the results obtained is presented.