bluuebunny/crossref_metadata_2025_split huggingface dataset:
Environmental aging of cold‐cured epoxy‐silica hybrids prepared by sol−gel process
Authors: Lionetto Francesca , Frigione Mariaenrica 
Published: October 2013

AbstractThe article investigates the effects of long term environmental aging on thermal and mechanical properties of epoxy‐silica hybrids. These nanostructured materials, prepared by non‐aqueous sol‐gel process and in situ generation of nanosilica during epoxy curing at room temperature, present the potential to be used as cold‐cured adhesives for civil engineering and Cultural Heritage applications. A specifically developed conditioning procedure for these cold‐cured nanostructured materials was applied before moisture/water absorption tests. The work evidenced the superior durability of the studied epoxy‐silica hybrid, which kept its performances in severe, but realistic, environmental conditions with respect to traditional epoxy adhesives. The reduction in the glass transition temperature and mechanical properties of the studied epoxy‐silica hybrid, observed in the first weeks of environmental aging, was followed by a significant recovery. This was attributed to two concomitant phenomena: the reactivation of the incomplete curing reactions in the epoxy domains and the continuation of the condensation reactions in the siloxane domains activated by the absorbed water. Finally, the Fickian behavior, presented by the studied epoxy‐silica hybrid, was used as an indirect indication of the homogeneity of achieved microstructure, with well dispersed silica nanostructures in the epoxy network. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40093.
Preparation of polyurethane foams using fractionated products in liquefied wood
Authors: Xu Junming , Jiang Jianchun , Hse Chung‐Yun , Shupe Todd F. 
Published: October 2013

AbstractLiquefaction of sawdust was studied using glycerol and methanol as mix solvents. A new bio‐polyol product consisting of high purity multi‐hydroxy compounds was obtained by precipitation of the hydrophobic organics from the liquefied product in an aqueous solution. As identified by GC‐MS, the dominate components in bio‐polyol were glycerol, glycerol derivatives, and multiple types of sugar derivatives. By using the mass ratio of m (sawdust) : m (glycerol) = 1 : 1, the total content of multi‐hydroxy compounds reached 90.84%. The hydroxyl number of the bio‐polyol was 1287 mgKOH/g with a rotational viscosity of 1270 cP. Preparation of polyurethane foams using bio‐polyol and isocyanate was also studied. Water was used as an environmental friendly blowing agent. The factors that influence the cell structure of foams (i.e., catalyst, dosage of blowing agent, and mass ratio of bio‐polyol to PEG‐400 were studied. The compressive strength of the synthesized foam was 150 Kpa, which met the requirement of Chinese specification for rigid foams. The synthesized foams were characterized by FTIR, SEM, and TG. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40096.
Adaptive e‐learning system based on agents and object petri nets (AELS‐A/OPN)
Authors: Hammami Salah , Mathkour Hassen 
Published: October 2013

AbstractAgent technology plays an important role in today's software development at the industrial level and brings advantages to the development of educational applications. The main focus of the multi‐agent systems community has been on the development of concepts, architectures, interaction techniques, and general approaches to the analysis and specification of multi‐agent systems. We introduce herein a novel concept involving the development of an e‐Learning system architecture that explores several recent technologies, including multi‐agent technology and adaptive e‐Learning. The main concern of our research is twofold: to build a multi‐agent architecture that provides the ability to adapt to the learner's preferences in the e‐Learning environment and to analyze and control the communication and interactions among the different agents of the proposed system. Toward this aim, we present a distributed intelligent blackboard agent that ensures the communication among the participating agents. Furthermore, we describe a formal model that can be used to specify the message exchanges and their synchronization using Object Petri Nets. An exploratory implementation has been developed and conducted in practice. © 2013 Wiley Periodicals, Inc. Comput Appl Eng Educ 23:170–190, 2015; View this article online at wileyonlinelibrary.com/journal/cae; DOI 10.1002/cae.21587
Three‐year outcomes of a once daily fractionation scheme for accelerated partial breast irradiation (APBI) using 3‐D conformal radiotherapy (3D‐CRT)
Authors: Goyal Sharad , Daroui Parima , Khan Atif J. , Kearney Thomas , Kirstein Laurie , Haffty Bruce G. 
Published: October 2013

AbstractThe aim of this study was to report 3‐year outcomes of toxicity, cosmesis, and local control using a once daily fractionation scheme (49.95 Gy in 3.33 Gy once daily fractions) for accelerated partial breast irradiation (APBI) using three‐dimensional conformal radiotherapy (3D‐CRT). Between July 2008 and August 2010, women aged ≥40 years with ductal carcinoma in situ or node‐negative invasive breast cancer ≤3 cm in diameter, treated with breast‐conserving surgery achieving negative margins, were accrued to a prospective study. Women were treated with APBI using 3–5 photon beams, delivering 49.95 Gy over 15 once daily fractions over 3 weeks. Patients were assessed for toxicities, cosmesis, and local control rates before APBI and at specified time points. Thirty‐four patients (mean age 60 years) with Tis 0 (n = 9) and T1N0 (n = 25) breast cancer were treated and followed up for an average of 39 months. Only 3% (1/34) patients experienced a grade 3 subcutaneous fibrosis and breast edema and 97% of the patients had good/excellent cosmetic outcome at 3 years. The 3‐year rate of ipsilateral breast tumor recurrence (IBTR) was 0% while the rate of contralateral breast events was 6%. The 3‐year disease‐free survival (DFS), overall survival (OS), and breast cancer‐specific survival (BCSS) was 94%, 100%, and 100%, respectively. Our novel accelerated partial breast fractionation scheme of 15 once daily fractions of 3.33 Gy (49.95 Gy total) is a remarkably well‐tolerated regimen of 3D‐CRT‐based APBI. A larger cohort of patients is needed to further ascertain the toxicity of this accelerated partial breast regimen.
Laminar Forced Convection of a Water‐TiO2 Nanofluid in Annuli Considering Mass Conservation for Particles
Authors: Bahiraei M. , Hosseinalipour S. M. , Hangi M. 
Published: October 2013

AbstractHydrothermal characteristics of a water‐TiO2 nanofluid were evaluated numerically within annuli considering the effects of particle migration. The convective heat transfer coefficients increased at both inner and outer walls of the annulus by raising the concentration. Along the annulus, the friction coefficient decreased more rapidly at lower Reynolds numbers. Taking the particle migration into account, a nonuniform concentration distribution was observed at the annulus cross section, higher heat transfer coefficients were obtained at both walls, and the velocity profile became flatter. In addition, the influence of thermophoresis on the convective heat transfer proved to be more significant than that of Brownian diffusion.
Enantioselective Bioaccumulation and Dissipation of Soil‐Associated Metalaxyl Enantiomers in Tubifex
Authors: Di Shanshan , Liu Tiantian , Lu Yuele , Zhou Zhiqiang , Diao Jinling 
Published: October 2013

ABSTRACTMany pesticides are chiral compounds and stereochemistry is an important factor for any reaction of chiral structures in biological systems. In this study, experiment about bioaccumulation of the two metalaxyl enantiomers in Tubifex (Oligochaeta, Tubificida) was conducted in laboratory aquatic ecosystems. Terrestrial soil spiked with two dose levels of metalaxyl was employed as the artificial bottom substrate. A method of determination of metalaxyl enantiomers in tubifex tissue, soil and overlying water were developed by HPLC. During a 14‐day exposure, concentrations of metalaxyl in tubifex increased with the of soil concentration, however, the enantioselective bioaccumulation was only detected at high‐dose exposure group, with the preferential accumulation of (‐)‐(R)‐metalaxyl. The bioturbation activity of tubifex decreased water clarity and released soil‐associated metalaxyl to overlying water. In those experiments where tubifex was exposed to metalaxyl from soil, pore water and overlying water, each route contributed to the total body burden, and our results indicated the pore water and soil are the primary exposure routes for high‐dose exposure concentration treatment. Chirality 26:33–38, 2013. © 2013 Wiley Periodicals, Inc.
Relationship of myocardial infarction to presence of angina pectoris in patients with coronary heart disease: Lack of abolition of angina by infarction
Authors: Amsterdam E. A. , Lee G. , Mathews E. A. , Mason D. T. 
Published: October 2013

AbstractTo evaluate the relationship between myocardial infarction and angina pectoris, history of symptomatic coronary heart disease was analyzed in 146 patients who had had documented myocardial infarction. There were 126 males and 70 females of mean age 55 years (range 32 to 70 years). Infarction had occurred 6 to 63 months prior to the study (mean: 30 months). Angina pectoris occurred at some time during the clinical course of 75 patients (51%), and 71 patients (49%) had not experienced angina. In the majority of the group with angina (n = 39; 52%) the symptom had not been present before infarction, appearing initially thereafter. Angina was present both before and after infarction in 31 patients (41%). In only 5 patients (7%) was precedent angina lost after infarction. Angina was, therefore, present in 70 of 146 patients (48%) after, compared to 36 patients (25%) before, infarction and in 86% (31/36) of patients with angina before infarction it persisted following the attack. Prior angina following myocardial infarction was not related to increased activity since in the majority of patients activity level was less after than before infarction. Post‐infarction cardiac failure, which developed in 9 patients who had prior angina, was not associated with abolition of angina in any of this group. It is concluded that: 1. angina is frequent after myocardial infarction, 2. when present before infarction it usually persists thereafter, 3. angina commonly appears as a new symptom after infarction when not previously present and 4. disappearance of angina after infarction is distinctly uncommon.
Effect of carbocromen induced coronary vasodilatation on myocardial metabolism in coronary artery disease
Authors: Kjekshus J. K. , Simonsen S. , Bøhmer T. 
Published: October 2013

AbstractMyocardial metabolism was studied during coronary vasodilatation by carbocromen during atrial pacing in patients with coronary arteriosclerotic disease. Coronary sinus flow was measured by the continuous infusion thermodilution technique. Carbocromen increased myocardial flow by the same amount at rest and during pacing‐induced tachycardia. The administration of carbocromen did not interfere with myocardial oxygen consumption, free fatty acid (FFA) uptake, pulmonary or systemic hemodynamics. Atrial pacing above the anginal threshold increased lactate and hypoxanthine excretion to the coronary sinus, but to a greater extent during carbocromen treatment. Thus, carbocromen is a specific coronary vasodilator acting independently of pacing induced vasodilatation. Metabolic data indicate a small but unfavourable effect on ischemic metabolism which might be due to a “coronary steal”.
The significance of systolic anterior motion (SAM) on the mitral valve echo pattern in hypertrophic cardiomyopathy
Authors: Gehrke J. , Goodwin J. F. 
Published: October 2013

AbstractThe systolic anterior motion (SAM) of valve structures in the mitral echogram in hypertrophic cardiomyopathy (HCM) has previously been considered to be anterior motion and re‐opening of mitral valve leaflets, causing left ventricular outflow tract (LVOT) obstruction and mitral regurgitation. Fifteen patients with HCM underwent cardiac catheterisation and were also examined by M‐scan and mechanical real‐time B‐scan techniques. In all patients SAM was seen during M‐scan echocardiography. The mitral valve leaflets were visualised during the entire cardiac cycle during real‐time B‐scanning without showing any re‐opening in systole. Thickened papillary muscles have been observed in 12 patients and prominent chordae tendineae moving in the opposite direction to the anterior mitral valve leaflet in 10 patients. Four patients with SAM did not show mitral regurgitation during left ventricular angiography. In two patients without fixed haemodynamic obstruction, a complete SAM touching the interventricular septum was observed with prolonged apposition in one case. These findings suggest that SAM is due to the motion of chordae tendineae and/or papillary muscles traversing the single dimensional ultrasonic beam in systole, thus producing single linear or multiple spotty echoes within SAM. The mechanism of the upward motion of the subvalvular mitral valve apparatus in systole appears to be due to forceful contraction of the apical left ventricular posterior wall. The observation of SAM in patients without HCM also indicates that its presence during single dimensional echocardiography is neither diagnostic nor specific for HCM, LVOT obstruction or mitral regurgitation, and contradicts the assumption that the anterior mitral valve leaflet plays a significant role in the mechanism of LVOT obstruction. The salient feature of all conditions associated with abnormal mitral subvalvular motion is hyperkinetic contraction of the apical left ventricular posterior wall. Hyperkinetic left ventricular ejection appears to be the main factor in the complex development of an LVOT gradient in hypertrophic cardiomyopathy.
Indication and clinical significance of exercise surface mapping
Authors: Fox K. M. , Selwyn A. P. , Shillingford J. P. 
Published: October 2013

AbstractA technique of recording electrocardiographic maps after exercise is described. This technique allows a measurement to be made of the area of ST segment changes that are projected onto the front of the chest after exercise. A comparison of the sensitivity and specificity of this technique with the orthogonal lead system and a single chest lead showed that praecordial exercise mapping was significantly superior to the other two lead systems in the diagnosis of ischaemic heart disease and may help in identifying patients with extensive disease. In addition information obtained from praecordial exercise mapping can be used to increase the data that are obtained from Holter monitoring of ST segments. The place of the technique in the management of medical and surgical treatment remains to be evaluated.
Cardiocirculatory adjustments during pregnancy — An echocardiographic study
Authors: Laird‐Meeter K. , van de Ley G. , Bom T. H. , Wladimiroff J. W. , Roelandt J. 
Published: October 2013

AbstractAdaptation of the circulation to pregnancy occurs via a complicated series of changes not yet completely understood. To define pertinent alterations, echocardiographic measurements of left ventricular function were performed every 4 weeks in 13 normal pregnant women. Six weeks postpartum each woman was reexamined; thus each woman served as her own nonpregnant control. Left ventricular dimensions, left ventricular wall thickness, shortening fraction, and rate of change of these measurements were recorded. As expected, cardiac output was increased throughout pregnancy. Up to 20 weeks gestation this occurred via an increased heart rate. After 20 weeks gestation stroke volume increased significantly, with 20% at 20‐26 weeks up to 30% at term (p < 0.01). With the end‐diastolic wall thickness remaining equal, myocardial hypertrophy occurred. This was corroborated by an increase in end‐systolic left ventricular wall thickness towards term: from 13.8 mm (S.D. ± 1.73) in early pregnancy to 16.6 mm (S.D. ± 1.62) at term, with end‐systolic left ventricular dimension unchanged. It was concluded that during pregnancy the mechanism to produce a higher cardiac output shifts from an increase in cardiac frequency to elevation of stroke volume with concomitant myocardial hypertrophy. Due to changes in heart rate and afterload, no conclusions could be drawn regarding myocardial contractility.
Intra‐aortic balloon pumping device for infants
Authors: Fukumasu H. , Blaylock R. , Veasy L. G. , Pons A. B. , Nielsen S. D. , Lawson J. L. , Kolff W. J. 
Published: October 2013

AbstractThe miniature components of an intra‐aortic balloon pumping system (IABP) have been successfully developed in this laboratory and have been effectively tested both in vitro and in 32 in vivo experiments using small animals weighing 3.5‐18 kg. It is reasonable to assume that IABP can be successfully employed for clinical use in infants and small children.
Left ventricular ejection fraction changes during recovery from treadmill exercise: A preliminary report of a new method for detecting coronary artery disease
Authors: Battler A. , Slutsky R. , Pfisterer M. , Ashburn W. , Froelicher V. 
Published: October 2013

AbstractTo test the value of combining treadmill exercise with radionuclide angiography for detecting exercise‐induced left ventricular dysfunction, ejection fractions were calculated at rest, peak supine bicycle exercise, and during three supine post‐treadmill recovery periods (2‐4 min, recovery 1; 4‐6 min, recovery 2; 8‐10 min, recovery 3) in ten coronary artery disease patients and eight normal subjects. Both the normal subjects and coronary artery disease patients had normal resting ejection fractions (>0.50). In the normal subjects the mean ejection fraction increased significantly (p<0.005) from rest (0.61 ± 0.03) to peak supine bicycle exercise (0.71 ± 0.04), and the mean ejection fraction also remained significantly higher (p<0.005) at rest than during 10 min post‐treadmill exercise. However, the coronary artery disease patients did not significantly change the mean ejection fraction from rest (0.59±0.06) to peak supine bicycle exercise (0.55±0.08), and the average ejection fraction during each one of the post‐treadmill recovery periods was not significantly different from rest. At the third recovery period all the normals but no coronary artery disease patients had higher ejection fraction than the resting ejection fraction. We thus conclude that the magnitude of change in ejection fraction from rest to 8‐10 min post‐treadmill exercise in patients with normal resting ejection fraction may be helpful in identifying those with coronary disease.
Echoventriculography in acute myocardial infarction. IV. Infarct size and reliability by pathologic anatomic correlations
Authors: Heikkilä J. , Nieminen M. S. 
Published: October 2013

AbstractA morphologic–echocardiographic comparison was carried out in 24 consecutive patients to determine the accuracy of multidirectional single‐beam echocardiography in imaging the size and site of 22 fatal acute myocardial infarctions and of 2 postinfarction ventricular aneurysms treated surgically.Echocardiography never missed the infarction, regardless of whether the infarction was anterior or posterior. The correlation between the echocardiographic and pathologic anatomic extent of infarct, as expressed by a percentage of the left ventricular horizontal circumference, was r = 0.88 (p<0.001). One hundred four of one hundred eleven infarcted segments (94%) were detected by echo; only the posterior septal and the most lateral segments of the left ventricle tended to remain out of range of the method. The regional asynergy at the center of the infarcted region was clear‐cut—systolic thickening was never seen and the systolic wall motion was paradoxical in 75% of the patients (mean, −2.0±2.0 mm). Analysis of the regional function from multiple sites characterized reduction of the left ventricular performance (p<0.0005) better than did the ejection fraction in the presence of asynergy. An old postinfarction scar was differentiated from the acute necrosis.Thus, segmental left ventricular akinesis or paradoxical motion as seen by multidirectional echocardiography permits noninvasively a reliable estimation of the extent of acute myocardial infarction.
The effects of propranolol on myocardial perfusion and metabolism during acute regional ischaemia
Authors: Fox K. M. , Selwyn A. P. , Welman E. 
Published: October 2013

AbstractThe unique physical properties of the short‐lived inert and freely diffusing isotope 81mkrypton allow a continuous observation to be made of regional myocardial perfusion. Eighteen dogs were anaesthetised and a reversible snare placed on the left anterior descending coronary artery (LAD). 81mKrypton was used to study regional myocardial perfusion, and myocardial metabolism was assessed using the epicardial ECG and release of creatine kinase activity (CK). Six dogs did not undergo LAD occlusion (“sham operated”); in six other dogs the LAD was occluded (controls), and another six dogs were given propranolol, 0.5 mg/kg, 20 min after LAD occlusion. All the parameters were measured before and for 5 h after LAD occlusion. When compared to controls, dogs treated with propranolol showed significant improvement (p<0.01) in regional myocardial perfusion; smaller loss of electrically active myocardium for any given degree of early ST‐segment elevation; and a delay in the release of CK activity from a local coronary vein. These results suggest that propranolol exerts a beneficial effect following the development of acute myocardial infarction.