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Selected AbstractsEcho-Tracking Assessment of Carotid Artery Stiffness in Patients with Aortic Valve StenosisECHOCARDIOGRAPHY, Issue 7 2009Francesco Antonini-Canterin M.D. Background: There is little information about mechanical properties of large arteries in patients (pts) with aortic stenosis (AS). Methods: Nineteen patients with AS (aortic valve area: 0.88 ± 0.29 cm2) and 24 control subjects without AS but with a similar distribution of risk factors were recruited. , index, pressure-strain elastic modulus (Ep), arterial compliance (AC), augmentation index (AIx), and local pulse-wave velocity (PWV) were obtained at the level of right common carotid artery (CCA) by a real time echo-tracking system. Time to dominant peak of carotid diameter change waveform, corrected for heart rate (tDPc), and maximum rate of rise of carotid diameter (dD/dt) were measured. Systemic arterial compliance (SAC) was also calculated. Parameters of AS severity (mean gradient, valve area, stroke work loss [SWL]) were determined. Results: tDPc was higher in patients with AS than in controls (7.9 ± 0.6 vs. 6.6 ± 0.7, P < 0.0001) while dD/dt was lower (5.3 ± 3.6 mm/s vs. 7.8 ± 2.8 mm/s, P = 0.01). AIx was significantly higher in AS group (32.5 ± 13.6% vs. 20.6 ± 12.2%, P = 0.005) and had a linear correlation both with tDPc (r = 0.63, P < 0.0001) and with dD/dt (r =,0.38, P = 0.01). There was a significant correlation between carotid AC and SAC (r = 0.49, P = 0.03), but only carotid AC was related to SWL (r = 0.51, P = 0.02), while SAC was not (P = 0.26).Conclusions: AIx was the only parameter of arterial rigidity found to be higher in patients with AS than in controls. Carotid AC showed a significant correlation with SAC and it seemed to be more closely related to AS severity than to SAC. [source] The Influence of Film Morphology in High-Mobility Small-Molecule:Polymer Blend Organic TransistorsADVANCED FUNCTIONAL MATERIALS, Issue 14 2010Jeremy Smith Abstract Organic field-effect transistors (OFETs) based upon blends of small molecular semiconductors and polymers show promise for high performance organic electronics applications. Here the charge transport characteristics of high mobility p-channel organic transistors based on 2,8-difluoro-5,11-bis(triethylsilylethynyl) anthradithiophene:poly(triarylamine) blend films are investigated. By simple alteration of the film processing conditions two distinct film microstructures can be obtained: one characterized by small spherulitic grains (SG) and one by large grains (LG). Charge transport measurements reveal thermally activated hole transport in both SG and LG film microstructures with two distinct temperature regimes. For temperatures >115,K, gate voltage dependent activation energies (EA) in the range of 25,60 meV are derived. At temperatures <115,K, the activation energies are smaller and typically in the range 5,30 meV. For both film microstructures hole transport appears to be dominated by trapping at the grain boundaries. Estimates of the trap densities suggests that LG films with fewer grain boundaries are characterized by a reduced number of traps that are less energetically disordered but deeper in energy than for small SG films. The effects of source and drain electrode treatment with self-assembled monolayers (SAMs) on current injection is also investigated. Fluorinated thiol SAMs were found to alter the work function of gold electrodes by up to ,1,eV leading to a lower contact resistance. However, charge transport analysis suggests that electrode work function is not the only parameter to consider for efficient charge injection. [source] Hippocampal lesions and discrimination performance of mice in the radial maze: Sparing or impairment depending on the representational demands of the taskHIPPOCAMPUS, Issue 2 2003Nicole Etchamendy Abstract The effects of ibotenate hippocampal lesions on discrimination performance in an eight-arm radial maze were investigated in mice, using a three-stage paradigm in which the only parameter that varied among stages was the way the arms were presented. In the initial learning phase (stage 1), animals learned the valence or reward contingency associated with six (three positive and three negative) adjacent arms of the maze using a successive (go/no-go) discrimination procedure. In the first test phase (stage 2), the six arms were grouped into three pairs, so that on each trial, the subject was faced with a choice between two adjacent arms of opposite valence (concurrent two-choice discrimination). In the second test phase (stage 3), the subject was faced with all six arms simultaneously (six-choice discrimination). Hippocampal-lesioned mice acquired the initial learning phase at a near-normal rate but behaved as if they had learned nothing when challenged with the two-choice discriminations at stage 2. In contrast, they behaved normally when confronted with the six-choice discrimination at stage 3. Detailed examination of within- and between-stage performance suggests that hippocampal-lesioned mice perform as intact mice when presentation of the discriminanda encourages the storage and use of separate representations (i.e., in initial learning and six-choice discrimination testing), but that they fail in test situations that involve explicit comparisons between such separate representations (two-choice discriminations), hence requiring the use of relational representations. Hippocampus 2003;13:197,211. © 2003 Wiley-Liss, Inc. [source] How two different host species influence the performance of a gregarious parasitoid: host size is not equal to host qualityJOURNAL OF ANIMAL ECOLOGY, Issue 2 2007JOHANNA HÄCKERMANN Summary 1Hyssopus pallidus Askew (Hymenoptera, Eulophidae) is a gregarious ectoparasitoid of the two tortricid moths species Cydia molesta Busck and C. pomonella L. (Lepidoptera, Tortricidae). It paralyses and parasitizes different larval instars of both species inside the apple fruit, which leads to the death of the caterpillar. 2We assessed the influence of host species characteristics and host food on the performance of the parasitoid female in terms of clutch size decisions and fitness of the F1 generation. 3A comparison of clutch size revealed that female parasitoids deposited similar numbers of eggs on the comparatively smaller C. molesta hosts as on the larger C. pomonella hosts. The number of parasitoid offspring produced per weight unit of host larva was significantly higher in C. molesta than in C. pomonella, which is contrary to the general prediction that smaller hosts yield less parasitoid offspring. However, the sex ratio was not influenced by host species that differed considerably in size. 4Despite the fact that less host resources were available per parasitoid larva feeding on C. molesta caterpillars, the mean weight of emerging female wasps was higher in the parasitoids reared on C. molesta. Furthermore, longevity of these female wasps was neither influenced by host species nor by the food their host had consumed. In addition we did not find a positive relationship between adult female weight and longevity. 5Parasitoid females proved to be able to assess accurately the nutritional quality of an encountered host and adjust clutch size accordingly. These findings indicate that host size is not equal to host quality. Thus host size is not the only parameter to explain the nutritional quality of a given host and to predict fitness gain in the subsequent generation. [source] Dynamic Gd-DTPA enhanced MRI as a surrogate marker of angiogenesis in tissue-engineered bladder constructs: A feasibility study in rabbitsJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 4 2005Hai-Ling Margaret Cheng PhD Abstract Purpose To evaluate the potential of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) to assess angiogenesis in tissue-engineered bladder constructs in a blinded animal study, and compare different analysis approaches and their correlation with microvessel density (MVD). Materials and Methods Constructs fortified with vascular endothelial growth factor (VEGF) for enhanced vascularity were grafted onto the bladder in nine rabbits. DCE-MRI of Gd-DTPA uptake was performed and analyzed using Tofts' model, the area under the concentration time curve (AUC), and the uptake slope. DCE-MRI parameters were compared to MVD determined with CD31 immunohistochemistry. Results Significantly increased MVD was found in the high VEGF group (20 ng/g of tissue) but not at low VEGF (10 ng/g) (2.3× increase, P = 0.035 vs. 1.1× over control). Enhanced permeability at low VEGF was suggested by elevated Ktrans, but overall correlation to MVD was poor. Significant correlation to MVD was obtained with AUC8min (r = 0.705, P = 0.034). Furthermore, AUC8min provided the most precise discrimination between different VEGF preparations and was the only parameter to show a significant increase (P = 0.0058) consistent with MVD changes at high VEGF. Conclusion Findings support DCE-MRI for evaluating angiogenesis in bladder constructs and suggest vessel changes other than density. Future studies should incorporate larger contrast agents and permeability assessment to devise an optimal DCE-MRI strategy. J. Magn. Reson. Imaging 2005;21:415,423. © 2005 Wiley-Liss, Inc. [source] Protostellar discs formed from rigidly rotating coresMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 1 2009S. Walch ABSTRACT We use three-dimensional smoothed particle hydrodynamic simulations to investigate the collapse of low-mass pre-stellar cores and the formation and early evolution of protostellar discs. The initial conditions are slightly supercritical Bonnor,Ebert spheres in rigid rotation. The core mass and initial radius are held fixed at MO= 6.1 M, and RO= 17 000 au, and the only parameter that we vary is the initial angular speed ,O. Protostellar discs forming from cores with ,O < 1.35 × 10,13 s,1 have radii between 100 and 300 au and are quite centrally concentrated; due to heating by gas infall on to the disc and accretion on to the central object, they are also quite warm, , and therefore stable against gravitational fragmentation. In contrast, more rapidly rotating cores form discs which are less concentrated and cooler, and have radii between 400 and 1000 au; as a consequence they are prone to gravitational fragmentation and the formation of multiple systems. We derive a criterion that predicts whether a rigidly rotating core having given MO, RO and ,O will produce a protostellar disc which fragments whilst material is still infalling from the core envelope. We then apply this criterion to core samples for which MO, RO and ,O have been estimated observationally. We conclude that the observed cores are stable against fragmentation at this stage, due to their low angular speeds and the heat delivered at the accretion shock where the infalling material hits the disc. [source] Interpretation of radial pulse contour during fentanyl/nitrous oxide anesthesia and mechanical ventilationACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 7 2002S. Söderström Background: Peripheral arterial blood pressure is not a reliable substitute for proximal aortic pressure. Recognition of this phenomenon is important for correct appreciation of cardiac afterload. Our aim was to evaluate the utility of the radial pulse wave to better understand ventriculo-vascular coupling during anesthesia. Methods: We observed the differences between aortic systolic pressure (AoSAP, tipmanometry) and radial systolic pressure in 15 patients, (including two women) aged 53,78 years, before coronary artery bypass surgery. We studied the induction of anesthesia with fentanyl (20 µg kg,1), moderate volume loading, and thereafter the addition of 70% nitrous oxide. The circulatory effects of mechanical ventilation were studied by doubling the tidal volumes. Pulse wave contours were assessed by calculation of radical and aortic augmentation indices (AI), which measure the second systolic pressure peak. Results: Radial systolic pressure was higher than AoSAP in the control situation (8±2 mmHg), and this SAP gradient increased further with fentanyl (12±2 mmHg). The gradient persisted throughout the study, but was partially reduced by volume loading and nitrous oxide, respectively. Radial augmentation index was the only parameter remaining in a stepwise multivariate model to explain the variance in the SAP gradient (r2=0.48). Radial augmentation index also correlated with aortic pulse pressure (r2=0.71). Mechanical ventilation had significant and similar effects on pulse wave augmentation both in the aorta and in the radial artery, and did not affect the radial to aortic SAP gradient. Conclusion: These elderly coronary patients had stiff vasculature (high aortic AI) and considerable pulse wave reflection, which was beneficially delayed by fentanyl. Changes in the radial pulse wave augmentation during mechanical ventilation were mainly a result of cyclic changes in the stroke volume, and were seldom associated with an increased systolic pressure gradient from the aorta to the radial artery. [source] Reliability of dynamometric passive properties of the pelvic floor muscles in postmenopausal women with stress urinary incontinenceNEUROUROLOGY AND URODYNAMICS, Issue 8 2008Mélanie Morin Abstract The passive properties of the pelvic floor muscles (PFM) might play a role in stress urinary incontinence (SUI) pathophysiology. Aim To investigate the test,retest reliability of the dynamometric passive properties of the PFM in postmenopausal SUI women. Methods Thirty-two SUI postmenopausal women were convened to two sessions 2 weeks apart. In each session, the measurements were repeated twice. The pelvic floor musculature was evaluated in four different conditions: (1) forces recorded at minimal aperture (initial passive resistance); (2) passive resistance at maximal aperture; (3) five lengthening and shortening cycles (Forces and passive elastic stiffness (PES) were evaluated at different vaginal apertures. Hysteresis was also calculated.); (4) Percentage of passive resistance loss after 1 min of sustained stretching was computed. The generalizability theory was used to calculate two reliability estimates, the dependability indices (,) and the standard error of measurement (SEM), for one session involving one measurement or the mean of two measurements. Results Overall, the reliability of the passive properties was good with indices of dependability of 0.75,0.93. The SEMs for forces and PES were 0.24,0.67 N and 0.03,0.10 N/mm, respectively, for mean, maximal and 20-mm apertures, representing an error between 13% and 23%. Passive forces at minimal aperture showed lower reliability (,,=,0.51,0.57) compared with other vaginal openings. The aperture at a common force of 0.5 N was the only parameter demonstrating a poor reliability (,,=,0.35). Conclusion This new approach for assessing PFM passive properties showed enough reliability for highly recommending its inclusion in the PFM assessment of SUI postmenopausal women. Neurourol. Urodynam. 27:819,825, 2008, © 2008 Wiley-Liss, Inc. [source] Beginning IVF Treatments After Age 30 Increases the Risk of Breast Cancer: Results of a Case,Control StudyTHE BREAST JOURNAL, Issue 6 2008Daniela Katz MD Abstract:, The long-term risks of in vitro fertilization (IVF) treatment remain unclear. This study was designed to determine breast cancer risk factors in women who underwent IVF, and to establish characteristics of these tumors. Records of 7,162 consecutive women who underwent IVF at a single center between 1984 and 2002 were linked with the Israel Cancer Registry to identify women who developed breast cancer. IVF-related parameters were compared between 28 breast cancer patients who had undergone IVF (IVF BC) and for whom complete IVF data were available with 140 women who underwent IVF and did not develop breast cancer (IVF non-BC). Tumor parameters were compared between 38 patients who developed breast cancer after IVF and 114 age-matched breast cancer patients who did not undergo IVF (non-IVF BC). Age over 30 at the time of first IVF treatment, even after controlling for age at first birth, was the only parameter significantly associated with increased breast cancer risk (RR = 1.24, p = 0.02, 95% CI = 1.03,1.48). There were no differences between IVF-BC and IVF non-BC patients in all other IVF-related parameters. The only statistically significant difference in tumors developing in IVF-BC patients compared with non-IVF BC patients was in grade distribution, particularly for grade II tumors. However, the significance of such a difference is unclear. Women who start IVF after the age of 30 appear to be at increased risk of developing breast cancer. The characteristics of breast tumors in women who underwent IVF are no different than in patients without previous exposure to IVF. [source] Laryngotracheal Anastomosis: Primary and Revised ProceduresTHE LARYNGOSCOPE, Issue 4 2001Michael Wolf MD Abstract Objectives Acquired upper airway stenosis is usually associated with a complex of pathological conditions at the high tracheal and the subglottic levels. Reported reconstructive techniques include widening by incorporation of grafts, segmental resection, and anastomosis or combined procedures. The management of recurrent stenosis after reconstructive surgery is a major challenge and has rarely been discussed in the literature. The purposes of the present study are to compare the clinical course of primary versus revised reconstructive procedures and to analyze the effect of age, diabetes, chronic lung disease, grading of stenosis, extent of resection, and revised procedures on the operative rate of success. Study Design A cohort study in a tertiary referral medical center. Methods The clinical course of 23 consecutive patients undergoing laryngotracheal anastomosis was studied comparing a group of 13 primary with 10 revision procedures. Seventeen patients underwent cricotracheal and six patients thyrotracheal anastomoses. All patients but one were tracheotomized before the definitive reconstructive procedure. Suprahyoid release was routinely performed except for two cases, and only one patient required sternotomy. The Wilcoxon test was used to examine the relationship between preoperative clinical parameters and the postoperative success (i.e., airway patency). Results Twenty-two of 23 patients (95.6%) had successful decannulation. Four patients required a revision procedure because of repeat stenosis at the site of the anastomosis (2) or distal tracheal malacia (2). Residual airway stenosis of less than 50% was noted in six patients, although only three complained of dyspnea during daily-activity exertion. There was no associated mortality. Complications included subcutaneous emphysema (4), granulation tissue formation (3), pneumonia (2), cardiac arrhythmia (2), and one each of pneumomediastinum, neck hematoma, and urosepsis. Protracted aspirations were noted in one patient who had revision surgery. Age was the only parameter that correlated with postoperative airway patency (P <.07), whereas the presence of chronic obstructive lung disease and diabetes, grade of stenosis, type of surgery, and revision surgery were found to be insignificant. Conclusions The clinical course of laryngotracheal anastomosis in primary and revised procedures was similar in our group of patients. The operation can be performed safely, with an expected high rate of success and acceptable morbidity. [source] White Blood Cell Count and the Occurrence of Silent Ischemia after Myocardial InfarctionANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 1 2003gorzata Kurpesa Background: Inflammation plays a role in the pathogenesis of atherosclerosis. Attempts are made to use markers of inflammation as prognostic factors in coronary artery disease and acute coronary syndromes. The correlation between inflammation and silent postinfarction ischemia is unknown. Methods: The study population consists of 104 asymptomatic patients who had uncomplicated Q-wave myocardial infarction within 6 months prior to the enrollment. After the white blood cell (WBC) count was assessed, the population was divided into two groups: group I comprising 48 patients with WBC , 7.0 × 103/,l and group II comprising 56 patients with WBC > 7.0 × 103/,l. Twenty-four-hour Holter monitoring was performed to detect the presence of silent ischemia. Results: Eighty-eight silent ischemic episodes were recorded. Ischemia on Holter monitoring was detected in 47 patients (84%) from group II and in five patients (9%) in group I (P < 0.01). We have found a significant positive correlation between WBC count and the number of ischemic episodes (r = 0.25), their maximal amplitude (r = 0.39), duration (r = 0.34), and total ischemic burden (r = 0.36). In multivariate analysis leucocytosis proved to be the only parameter independently correlated with the presence of silent ischemia. Conclusion: Postinfarction asymptomatic patients with increased WBC count are more likely to have residual ischemia. [source] ,-Globin gene cluster haplotypes and HbF levels are not the only modulators of sickle cell disease in LebanonEUROPEAN JOURNAL OF HAEMATOLOGY, Issue 2 2003A. Inati Abstract: Sickle cell disease (SCD) is an inherited autosomal recessive disorder of the , -globin chain. Despite the fact that all subjects with SCD have the same single base pair mutation, the severity of the clinical and hematological manifestations is extremely variable. This study examined for the first time in Lebanon the correlation between the clinical manifestation of SCD and the , -globin gene haplotypes. The haplotypes of 50 patients diagnosed with SCD were determined using polymerase chain reaction amplification of fragments containing nine polymorphic restriction sites around and within the ,,G,,A,,,,,,,, -globin gene complex. Most reported haplotypes were found in our population with the Benin haplotype as the most prevalent one. When the patients were divided according to their HbF levels into three groups (Group A: HbF < 5%, Group B: HbF between 5 and 15%, and Group C: HbF > 15%), surprisingly, the highest levels of HbF were associated with the most severe clinical cases. Our findings suggest that fetal hemoglobin levels are important but not the only parameters that affect the severity of the disease. In addition, the high levels of HbF in patients with CAR haplotypes did not seem to ameliorate the severity of symptoms, suggesting that genetic factors other than haplotypes are the major determinants of increased HbF levels in Lebanon. [source] Flexible models with evolving structureINTERNATIONAL JOURNAL OF INTELLIGENT SYSTEMS, Issue 4 2004Plamen P. Angelov A type of flexible model in the form of a neural network (NN) with evolving structure is discussed in this study. We refer to models with amorphous structure as flexible models. There is a close link between different types of flexible models: fuzzy models, fuzzy NN, and general regression models. All of them are proven universal approximators and some of them [Takagi-Sugeno fuzzy model with singleton outputs and radial-basis function] are interchangeable. The evolving NN (eNN) considered here makes use of the recently introduced on-line approach to identification of Takagi-Sugeno fuzzy models with evolving structure (eTS). Both TS and eNN differ from the other model schemes by their gradually evolving structure as opposed to the fixed structure models, in which only parameters are subject to optimization or adaptation. The learning algorithm is incremental and combines unsupervised on-line recursive clustering and supervised recursive on-line output parameter estimation. eNN has potential in modeling, control (if combined with the indirect learning mechanism), fault detection and diagnostics etc. Its computational efficiency is based on the noniterative and recursive procedure, which combines the Kalman filter with proper initializations and on-line unsupervised clustering. The eNN has been tested with data from a real air-conditioning installation. Applications to real-time adaptive nonlinear control, fault detection and diagnostics, performance analysis, time-series forecasting, knowledge extraction and accumulation, are possible directions of their use in future research. © 2004 Wiley Periodicals, Inc. [source] Soluble urokinase-type plasminogen activator receptor (suPAR) as an independent factor predicting worse prognosis and extra-bone marrow involvement in multiple myeloma patientsBRITISH JOURNAL OF HAEMATOLOGY, Issue 6 2003Gian Matteo Rigolin Summary. The urokinase-type plasminogen activator (uPA) system, which consists of a proteinase (uPA), a receptor (uPAR or CD87) and inhibitors, is involved in proteolysis, cell migration, tissue remodelling, angiogenesis and cell adhesion. Recent findings suggest that malignant plasma cells express uPA and uPAR. The expression of these factors could represent a process by which myeloma plasma cells interact with the bone marrow (BM) environment and influence important biological events such as bone matrix degradation, plasma cell invasion and homing and, possibly, clinical evolution. We evaluated uPAR (CD87) and its soluble form (suPAR) in 49 multiple myeloma (MM) patients and correlated their expression and levels with clinico-biological characteristics of the disease. Flow cytometric analysis demonstrated that CD87 was expressed in all MM patients. High CD87 expression was associated with higher intensity of expression of CD56 (P = 0·038), CD38 (P = 0·058) and CD138 (P = 0·054) and CD45bright positivity (P = 0·014). suPAR levels correlated positively with soluble serum CD138 (P = 0·001), creatinine (P = 0·001), beta2 -microglobulin (P < 0·001), disease stage (P = 0·017) and extra-BM involvement (P = 0·002). In the 46 evaluable patients, multivariate analysis showed that high levels of suPAR (P = 0·0214) and disease stage (P = 0·0064) were predictive of extra-BM involvement. In multivariate Cox analysis, 13q deletion (P = 0·0278), high soluble serum CD138 (P = 0·0201) and high suPAR (P = 0·0229) were the only parameters that independently affected survival. We conclude that CD87 is expressed on myeloma plasma cells and that suPAR, which predicts extra-BM involvement and poor prognosis, possibly represents a molecule with a relevant role in the biology of MM. [source] | ||||||||||||||||||||||