bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect of the levonorgestrel-releasing intrauterine system on the resistance to activated protein C (APC)
Authors: Tchaikovski Svetlana , Rosendaal Frits , Rosing Jan , Helmerhorst Frans , van Vliet Huib 
Published: March 2009

SummaryExogenously administered estrogens and progestogens as during combined oral contraceptive use increase the risk of venous thrombosis. The thrombin generation-based APC resistance assay is a global coagulation test that enables quantification of the net prothrombotic effect of combined oral contraceptives and that predicts the risk of thrombosis. The thrombotic risk of the levonorgestrel-releasing intrauterine system is unknown. It was the objective of this study to evaluate the thrombotic risk by comparing the APC resistance before and after insertion of a levonorgestrel-releasing or a copper-containing intrauterine device. We measured normalized APC-sensitivity ratios (nAPCsr) before and three months after insertion of the levonorgestrelintrauterine system in 56 women and the copper-intrauterine device in 18 women. In women without hormonal contraceptive use or a pregnancy in the three months before collection of the baseline samples, nAPCsr were lower three months after insertion of the levonorgestrel-intrauterine system than at baseline (difference –0.29; 95% CI –0.04 to –0.53) and hardly changed after insertion of the copper-intrauterine device (difference -0.11; 95% CI –1.03 to 0.82). In women who switched from a combined oral contraceptive to the levonorgestrel-system the difference was more pronounced (-1.48; 95% CI –0.85 to –2.11). In this study we observed that the levonorgestrel-intrauterine system decreases the resistance to APC which indicates that the levonorgestrel-intrauterine system does not have a prothrombotic effect.
Role of H2O2-activated TRPM2 calcium channel in oxidant-induced endothelial injury
Authors: Hecquet Claudie , Malik Asrar 
Published: March 2009

SummaryThe transient receptor potential (melastatin) 2 (TRPM2), is an oxidant-activated non-selective cation channel that is widely expressed in mammalian tissues including the vascular endothelium. Oxidative stress, through the generation of oxygen meta-bolites including H2O2, stimulates intracellular ADP-ribose formation which, in turn, opens TRPM2 channels. These channels act as an endogenous redox sensor for mediating oxidative stress/ROS-induced Ca2+ entry and the subsequent specific Ca2+-dependent cellular reactions such as endothelial hyper-permeability and apoptosis. This review summarizes recent findings on the mechanism by which oxidants induce TRPM2 activation, the role of these channels in the signalling vascular endothelial dysfunctions, and the modulation of oxidant-induced TRPM2 activation by PKCα and phospho-tyrosine phosphates L1.
Signalling pathways in ischaemic postconditioning
Authors: Hausenloy Derek 
Published: March 2009

SummaryCoronary heart disease (CHD) is the leading cause of death globally. Following an acute coronary artery occlusion, timely myocardial reperfusion using either primary percutaneous coronary intervention (PCI) or thrombolytic therapy remains the most effective treatment strategy for reducing myocardial infarct size, preventing left ventricular remodelling, preserving left ventricular systolic function and improving clinical outcomes. However, the full benefits of myocardial reperfusion are not realised, given that the actual process of reperfusing ischaemic myocardium can independently induce cell death – a phenomenon termed lethal reperfusion injury. Ischaemic postconditioning represents an innovative treatment strategy for limiting lethal myocardial reperfusion injury and further reducing myocardial infarct size for those patients undergoing primary PCI. It is achieved by interrupting the normal myocardial reperfusion process, with several intermittent episodes of coronary myocardial ischaemia induced by low-pressure inflations of the angioplasty balloon in the infarct-related coronary artery. Experimental studies demonstrate that this stuttered form of myocardial reperfusion improves myocardial perfusion, maintains endothelial function, attenuates apoptotic cell death, reduces myocardial infarct size, preserves left ventricular systolic function and reduces mortality. The mechanisms underlying the cardioprotective effect of ischaemic postconditioning are the subject of intense investigation. In this article we review the signalling pathways which have been implicated as potential mediators of ischaemic postconditioning, the identification of which have provided novel pharmacological targets of cardioprotection capable of recapitulating the protective benefits of ischaemic postconditioning.
Myocardial protection against reperfusion injury: The cGMP pathway
Authors: Agulló Luis , Sartorio Carmem Lluisa , Ruiz-Meana Marisol , Garcia-Dorado David 
Published: March 2009

SummaryReperfusion injury may cause myocardial cell death and limit the benefit achieved by restoration of coronary artery patency in patients with acute myocardial infarction. The mechanism includes altered Ca2+ handling with cytosolic and mitochondrial Ca2+ overload, Ca2+- and ATP-dependent hypercontraction, cytoskeletal fragility, mitochondrial permeability transition and gap junction-mediated propagation of cell death, as well as alterations in non-cardiomyocyte cells, in particular platelets and endothelial cells. cGMP modulates favorably all these mechanism, mainly through PKG-mediated actions, but cGMP synthesis is altered in reperfused cardiomyocytes and endothelial cells by mechanisms that are only partially understood. Stimulation of cGMP synthesis during initial reperfusion by means of natriuretic peptides has been found protective in different animal models and in patients. Moreover, increasing evidence indicates that cGMP is an important step in signal transduction of endogenous cardioprotection. Thus, the cGMP pathway appears as a key element in the pathophysiology of myocardial ischaemiareperfusion and as a promising therapeutic target in patients with acute myocardial infarction.
Acquired factor V inhibitor
Authors: Kuperan Ponnudurai , Ng Chin Hin , Ng Heng Joo , Ang Ai Leen 
Published: March 2009

SummaryAcquired factor V(FV) inhibitors as a rare bleeding disorder, poses a formidable challenge to treating physicians with limited evidence to guide its management. We systematically reviewed our experience in Singapore and the published literature to determine possible answers to clinical questions formulated on the manifestation and best management of non-bovine thrombin and non-congenital acquired FV inhibitors. The incidence in Singapore was 0.09 cases per million person years (3 cases over 10 years). Seventy-three other cases meeting pre-defined search criteria were found in the published literature. Bleeding occurred in 68.4% of these patients, with mucous membranes being the most common site. Intracranial and retroperitoneal bleeds carried the highest mortality. The mortality rate from bleeding was 12%. There was a tendency for FV levels and PT/aPTT prolongation to predict bleeding but not the inhibitor level. No consistently effective haemostatic agent could be determined, but platelet transfusion should probably be the first line therapy. Among bleeding patients, inhibitors tended to disappear faster with inhibitor elimination therapy (IET) compared to without IET (60 vs. 150 days, p=0.299). IET made no significant difference among non-bleeding patients (p=0.511) and is thus recommended for bleeding patients or those with high bleeding risk. Steroids as single agent IET was effective in the majority of patients. Logical management approaches may be drawn but are limited by small sample size, heterogeneity of reports, and potential publication bias. The inception of a comprehensive registry will provide more reliable data that may verify our findings.
Comments on “Does Air Pollution Really Suppress Precipitation in Israel?”
Authors: Givati Amir , Rosenfeld Daniel 
Published: March 2009

Abstract
Alpert et al. in a recent paper challenged the quantification of the suppression of orographic precipitation that was shown in two recent papers by Givati and Rosenfeld to occur in Israel. Their main claim was that the results were determined by the selection of the rain gauges. In this comment, it is demonstrated that when an objective selection of the rain gauges is applied to all of the rain gauges that were used by Alpert et al. and Givati and Rosenfeld, the outcome replicates the results of Givati and Rosenfeld and provides additional insights. At the final account, this comment further enhances the confidence that orographic precipitation has been suppressed over Israel. The direct evidence to the cause is still lacking.
Novel Design of Dual Functional Hydrogen Separation Membranes
Authors: Song Sun-Ju , Lee Tae H , Dorris Steve E , Balachandran U (Balu) 
Published: March 2009

Abstract
The novel design of cermet membranes is reported here, which are capable of simultaneously transporting two gas species through membrane metal with high hydrogen permeability in a thermodynamically stable oxygen-ion-conducting ceramic matrix. This novel, dual-function cermet membrane should allow the maximum hydrogen production by combining the ability of hydrogen production from water with the function of hydrogen separation on membranes. An hydrogen production rate of ca. 2.7 cm3(STP)/min·cm2 for 0.21-mm-thick membrane at 900 °C was obtained, using 50 vol % water vapor on one side of the membrane and 80%/20% hydrogen/helium on the other side.
Sources and Sinks of Carbon Dioxide
Authors: Quirk Tom 
Published: March 2009

The conventional representation of the impact on the atmosphere of the use of fossil fuels is to state that the annual increases in concentration of CO2 come from fossil fuels and the balance of some 50% of fossil fuel CO2 is absorbed in the oceans or on land by physical and chemical processes. An examination of the data from: i) measurements of the fractionation of CO2 by way of Carbon-12 and Carbon-13 isotopes, ii) the seasonal variations of the concentration of CO2 in the Northern Hemisphere and iii) the time delay between Northern and Southern Hemisphere variations in CO2, raises questions about the conventional explanation of the source of increased atmospheric CO2. The results suggest that El Nino and the Southern Oscillation events produce major changes in the carbon isotope ratio in the atmosphere. This does not favour the continuous increase of CO2 from the use of fossil fuels as the source of isotope ratio changes. The constancy of seasonal variations in CO2 and the lack of time delays between the hemispheres suggest that fossil fuel derived CO2 is almost totally absorbed locally in the year it is emitted. This implies that natural variability of the climate is the prime cause of increasing CO2, not the emissions of CO2 from the use of fossil fuels.
Earth's Radiative Equilibrium in the Solar Irradiance
Authors: Hertzberg Martin 
Published: March 2009

The average equilibrium temperature for all the Earth's entities involved in its radiative balance with the Sun and Space, is given by: T (e) [K] = 278.9 [(1 - α) / ɛ] The controlling factor is the ratio of the absorptivity, a = (1 - α), to the emissivity, ɛ. The quantity α is the Earth's albedo. It is shown that relatively modest changes of only a few percent in α, brought about by variations in cloudiness, are sufficient to account for the observed 20th Century variations in Earth's measured temperature, provided that such variations in cloudiness can cause an imbalance in the ratio (1 - α) / ɛ. The analysis suggests that in the long run, the absorptivity to emissivity ratio is near unity, as required by Kirchhoff's radiation law, which ensures a moderate average temperature of about 5.7 C for the Earth's surface entities. That calculated temperature is in fair agreement with the observed average temperature of those entities, whose mass average is dominated by the mass of the oceans. Except for the influence of clouds on the albedo, no assumptions are needed regarding the detailed composition of the atmosphere in order to explain the observed small fluctuations in the 20th Century temperatures or the larger, longer-term variations of Glacial Coolings and Interglacial Warmings.
Evidence That Stainable Bone Marrow Iron Following Parenteral Iron Therapy Does Not Correlate With Serum Iron Studies and May Not Represent Readily Available Storage Iron
Authors: Thomason Ronald W. , Almiski Muhamad S. 
Published: March 2009

Abstract
We recently reported that parenteral iron therapy is associated with a characteristic pattern of iron staining on bone marrow aspirate smears. We now present clinical information from 6 patients who received parenteral iron and, at one or more points in follow-up, were found to have low or borderline low serum ferritin levels and/or serum iron levels, even though marrow aspirate smears revealed abundant stainable iron in the pattern characteristic of prior parenteral iron therapy. We conclude that stainable iron seen in this pattern does not correlate with serum iron studies and may not represent functionally available storage iron. This pattern of iron staining should not be used as evidence to withhold further iron therapy in patients who otherwise continue to have features of iron deficiency anemia.
Two-dimensional NMR studies of acrylate copolymers
Authors: Brar A. S. , Goyal Ashok Kumar , Hooda Sunita 
Published: March 2009

Abstract
High-resolution NMR spectroscopy is the most versatile, reliable, and generally acceptable technique for the determination of the microstructure of polymers. 2D NMR techniques, along with 1D NMR, have more potential to study absolute configurational assignments and sequence distribution of copolymers. Physical and chemical properties of polymers are influenced fundamentally by their microstructure. We discuss the detailed microstructure analysis of a large number of homopolymers, copolymers, and terpolymers. 2D NMR study of poly(methyl methacrylate) (PMMA), poly(methyl acrylate) (PMA), and poly(methacrylonitrile) (PMAN) is discussed in this article. In addition to homopolymers, 2D heteronuclear single-quantum coherence (HSQC), total correlation spectroscopy (TOCSY), and heteronuclear multiple-bond correlation (HMBC) study of different copolymers such as poly(methyl methacrylate-co-methyl acrylate), poly(styrene-co-methyl methacrylate), and poly(methyl methacrylate-co-methacrylonitrile) have also been reported here. This in turn helps in microstructural analysis of terpolymers such as poly(methacrylonitrile-co-styrene-co-methyl methacrylate), poly(acrylonitrile-co-methyl methacrylate-co-methyl acrylate), and poly(ethylene-co-vinyl acetate-co-carbon monoxide).
Gelation mechanism of ultra-high-molecular-weight polyethylene (UHMWPE) chains in dispersion solutions containing multiwall carbon nanotubes (MWNTs) analyzed in terms of liquid-liquid phase separation
Authors: Matsuo Masaru , Yamanaka Atsuko , Nakano Yumiko 
Published: March 2009

Abstract
Gelation mechanisms of ultra-high-molecular-weight polyethylene (UHMWPE) in dispersion solutions containing multiwall carbon nanotubes (MWNTs) were investigated in terms of liquid-liquid phase separation mechanisms. When an incident beam of He-Ne gas laser was directed to the dispersion solution quenched to a desired temperature, the logarithm of scattered intensity increased linearly with elapsing time and tended to deviate from this linear relationship. The two different increasing behaviors of the scattered intensity were termed as initial and latter stages, respectively, of the phase separation. The linear increase in logarithmic light-scattered intensity was analyzed within the framework of the linear theory of spinodal decomposition in terms of the viewpoint that the quenched solution becomes thermodynamically unstable and tends to incur phase separation to resolve the unstable state. The growth rate of the concentration fluctuation of neat UHMWPE solution (without MWNTs) calculated from the slope of linear increase was faster than that of the dispersion solution. In spite of the rapid growth rate, however, the gelation time of the dispersion solution was much shorter than that of the neat UHMWPE solution and the gelation and quasi-spinodal temperatures were slightly higher. These phenomena were in contradiction with the result of the concentration fluctuation. This contradiction was thought to be due to the fact that diffused UHMWPE chains in the dispersion solution were gelled easily on the MWNT surface rather than the gelation by self-coagulation.
Reliability and prediction of long-term performance of polymer-based materials
Authors: Brostow Witold 
Published: March 2009

Abstract
The prediction of long-term performance from short-term tests is the bottom line of polymer science and engineering for users of polymer-based materials (PBMs) - which means for scientists, engineers, and laymen, or, literally, for everybody. Methods of prediction of mechanical properties (creep, stress relaxation, dynamic mechanical behavior, tension, etc.) based on the chain relaxation capability (CRC), the stress-time and temperature-time correspondence principles are presented. The methods can be applied even to small amounts of experimental data (2 or 3 isotherms or 2 or 3 stress levels) and can produce much better results than the still used 1955 Williams-Landel-Ferry (WLF) equation. Successful applications of the CRC approach include multiphase systems, including polymer liquid crystal (PLC) copolymers. An extension to the tribological properties of PBMs (in particular, scratch healing) is outlined. A quantitative definition of materials brittleness was formulated in 2006; it is connected to results in both the mechanics and tribology of PBMs.
Relationship Between Water Solubility, Soil Sorption, Octanol-Water Partitioning, and Concentration of Chemicals in Biota
Authors: Kenaga EE , Goring CAI 
Published: March 2009

There is a need for a method of preliminary estimation of bioconcentration factors in fish and soil sorption coefficients for chemicals. A data base was assembled for 170 compounds having average values for these two parameters and also average values for water solubility and n-octanol-water partition coefficients. Binary regression equations between the logarithms of these values gave correlation coefficients that were all significant below the 1 percent level. Using these equations, measured average values for any of the four parameters could be used to estimate average values for the unmeasured parameters. The 95 percent confidence limits for the calculated values were about ±1 to 3 orders of magnitude of the measured values. The relatively large variation of the actual from the predicted values was due both to the variation in the type of methodology used to make the measurements and also to the intrinsic variation in values attributable to the nature of the chemicals, the characteristics of the soils and fish, and the environmental conditions employed in the studies. Much less variation between actual and predicted values has been achieved when more uniform methodology is adopted for measuring these parameters. Despite the variability, the data are useful for early assessment of the potential for bioconcentration and mobility in the environment. Knowledge of the two factors is needed for hazard assessment in the environment.
Bioconcentration factor values for Daphnia appear to be as valid for correlation purposes as those for fish.
Application of Formability Assessment to Autobody Outer Panels
Authors: Furubayashi T , Kojima M 
Published: March 2009

Sheet metal formability in the press forming of autobody outer panels corresponds to the forming limits governed by fracture and geometrical defects. The geometrical surface defects are affected especially by the geometry of the die face. This kind of formability in a wider sense has been investigated by using simulated experimental dies of different geometry in the die face.
The forming limit relating to fracture is closely related to the r- and n-values, while the forming limit of surface defects is governed by the yield point.
Upsetting Test for Determining Stress-Strain Curves in the Range of Very High Strains
Authors: Pöhlandt K , Roll K 
Published: March 2009

In the upsetting test, stress-strain curves can be determined up to very high strains. However, two sources of error make the result increasingly inaccurate with growing strain: friction, and the error of measurement of the instantaneous specimen height.
Two methods are described by which these errors—or at least one of them—can be suppressed. The first method consists in the use of specimens according to Rastegaev. These specimens give excellent lubrication conditions and remain almost exactly cylindrical during testing, but the measurement of the instantaneous specimen height is even more inaccurate than for conventional specimens.
In the second method, both errors are suppressed by using a new kind of specimen, the diameter of which is larger at the ends than in the middle section. As a result, the work required for friction is suppressed, and in addition the error of height measurement propagates only weakly into the calculated values of strain and stress. This is demonstrated both by experiments and by calculations based on the finite-element method.
Formability Testing for Precision and Accuracy
Authors: Niemeier BA 
Published: March 2009

The author views the ability to shape press-formed parts with the logic and reason that are definitive of science. Materials which are in existence and those which are being developed for shape changeability are considered from intrinsic and extrinsic characteristics of force-deformation situations. Both mathematical modeling and statistics of precision and accuracy are introduced for direct measurements, such as depth to fracture. Elasticity and plasticity characteristics, which are both dimensionalized and nondimensionalized parametric relationships, are related to the fundamental physical variables of force and length.
Precision and accuracy are first presented in a simplistic format. Common and not-so-common parametric terms, such as stress, strain, strain hardening, and texture hardness, are used to indicate significance of precision. While numbers, charts, graphs, and equations are provided to handle abstract variables, full insight into the complete phenomena of numerical precision and accuracy remains with each investigator.
Levels of success and failure in correlating formability response are described from selected cooperative research. Included are encoded data from a large number of industrial and academic mechanical testing laboratories. Inter- and intralaboratory comparisons are related. There is the zone of uncertainty which may be deduced from a zone of confusion. Correlation or lack of the same is ascribed to an inadequately small zone of uncertainty. Statistical viewpoints of the author are offered through an in-depth level of references.