The Effect of Web-based Professional Development Study to Mathematics Teachers’ Problem Solving Strategies

AbstractThis research analyzes the problem-solving strategies adopted by math teachers in middle school and explores the role of web-based professional development studies in improving this process. The case group is constituted by twelve math teachers teaching in middle school. These twelve teachers have been arranged a seven-week web-based professional development study in problem-solving strategies. In collecting the data, pre- and post-testing, interview and observation methods have been exercised. On the basis of content analysis, the data obtained have been examined through an inductive strategy

Withdrawing intra-aortic balloon pump support paradoxically improves microvascular flow

Introduction: The Intra-Aortic Balloon Pump (IABP) is frequently used to mechanically support the heart. There is evidence that IABP improves microvascular flow during cardiogenic shock but its influence on the human microcirculation in patients deemed ready for discontinuing IABP support has not yet been studied. Therefore we used sidestream dark field imaging (SDF) to test our hypothesis that human microcirculation remains unaltered with or without IABP support in patients clinically ready for discontinuation of mechanical support. Methods: We studied 15 ICU patients on IABP therapy. Measurements were performed after the clinical decision was made to remove the balloon catheter. We recorded global hemodynamic parameters and performed venous oximetry during maximal IABP support (1:1) and 10 minutes after temporarily stopping the IABP therapy. At both time points, we also recorded video clips of the sublingual microcirculation. From these we determined indices of microvascular perfusion including perfused vessel density (PVD) and microvascular flow index (MFI). Results: Ceasing IABP support lowered mean arterial pressure (74 +/- 8 to 71 +/- 10 mmHg; P = 0.048) and increased diastolic pressure (43 +/- 10 to 53 +/- 9 mmHg; P = 0.0002). However, at the level of the microcirculation we found an increase of PVD of small vessels <20 mu m (5.47 +/- 1.76 to 6.63 +/- 1.90; P = 0.0039). PVD for vessels >20 mu m and MFI for both small and large vessels were unaltered. During the procedure global oxygenation parameters (ScvO(2)/SvO(2)) remained unchanged. Conclusions: In patients deemed ready for discontinuing IABP support according to current practice, SDF imaging showed an increase of microcirculatory flow of small vessels after ceasing IABP therapy. This observation may indicate that IABP impairs microvascular perfusion in recovered patients, although this warrants confirmatio

Impairment of Executive Functions and Memory in Unaffected Siblings of Patients with Bipolar Disorder

Objective: Neurocognitive impairments in bipolar patients as a possible endophenotype is a growing field of research. Impairments in executive functions and memory have been reported in relatives of patients with bipolar disorder, suggesting that they could be potential endophenotypes for genetic studies. In this study, neuropsychological performance in unaffected siblings of patients diagnosed as bipolar I disorder is compared to that of matched healthy controls

Microcirculatory Imaging in Cardiac Anesthesia: Ketanserin Reduces Blood Pressure But Not Perfused Capillary Density

Objectives: It has become possible to image the human microcirculation at the bedside using sidestream dark field (SDF) imaging. This may help the clinician when correlation between global and microvascular hemodynamics may not be straightforward. Ketanserin, a serotonin and α-1 adrenoceptor antagonist, is used in some countries to treat elevated blood pressure after extracorporeal circulation. This might hamper microcirculatory perfusion. Conversely, it is also conceivable that microcirculatory flow is maintained or improved as a result of flow redistribution. In order to introduce SDF imaging in cardiac anesthesia, the authors set out to directly observe the sublingual microcirculation in this setting. Design: An observational study. Setting: A large teaching hospital. Participants: Mechanically ventilated patients with elevated arterial blood pressure immediately after extracorporeal circulation (ECC). Intervention: An intravenous bolus of ketanserin, 0.15 mg/kg. Measurements and Main Results: Five minutes before and 10 minutes after ketanserin administration, global hemodynamic variables were recorded. In addition, the authors used SDF imaging to record video clips of the microcirculation. Analysis of these allowed for quantification of microvascular hemodynamics including determination of perfused vessel density (PVD) and microcirculatory flow index (MFI). After ketanserin administration, there was a significant reduction in systolic arterial blood pressure (129 ± 9 to 100 ± 15 mmHg, p = 0.0001). At the level of the microcirculation, the mean MFI did not change significantly for small (diameter 20 μm, 2.83 [1.4-3] to 2.67 [0.35-2.84] p = 1.0) vessels. There was a significant increase in mean PVD for large vessels (1.23 ± 0.63 to 1.70 ± 79 mm-1, p = 0.017) but not for small vessels (5.59 ± 2.60 to 5.87 ± 1.22 mm-1, p = 0.72) where red blood cell flow was maintained. Conclusions: SDF imaging clearly showed a discrepancy between global and microvascular hemodynamics after the administration of ketanserin for elevated blood pressure after ECC. Ketanserin effectively lowers arterial blood pressure. However, capillary perfusion is maintained at a steady value. Both effects may be explained by an increase in shunting in the larger vessels of the microcirculation

Mesoscale morphologies of Nafion-based blend membranes by dissipative particle dynamics

This article belongs to the Special Issue Multifunctional Hybrid Materials Based on Polymers: Design and Performance.Polymer electrolyte membrane (PEM) composed of polymer or polymer blend is a vital element in PEM fuel cell that allows proton transport and serves as a barrier between fuel and oxygen. Understanding the microscopic phase behavior in polymer blends is very crucial to design alternative cost-effective proton-conducting materials. In this study, the mesoscale morphologies of Nafion/poly(1-vinyl-1,2,4-triazole) (Nafion-PVTri) and Nafion/poly(vinyl phosphonic acid) (Nafion-PVPA) blend membranes were studied by dissipative particle dynamics (DPD) simulation technique. Simulation results indicate that both blend membranes can form a phase-separated microstructure due to the different hydrophobic and hydrophilic character of different polymer chains and different segments in the same polymer chain. There is a strong, attractive interaction between the phosphonic acid and sulfonic acid groups and a very strong repulsive interaction between the fluorinated and phosphonic acid groups in the Nafion-PVPA blend membrane. By increasing the PVPA content in the blend membrane, the PVPA clusters’ size gradually increases and forms a continuous phase. On the other hand, repulsive interaction between fluorinated and triazole units in the Nafion-PVTri blend is not very strong compared to the Nafion-PVPA blend, which results in different phase behavior in Nafion-PVTri blend membrane. This relatively lower repulsive interaction causes Nafion-PVTri blend membrane to have non-continuous phases regardless of the composition.U. Sen was supported by JSPS RONPAKU (Dissertation PhD) program with ID No. TUR 11008.Peer reviewe

Microvascular hemodynamics in human hypothermic circulatory arrest and selective antegrade cerebral perfusion

Objective: The behavior of the human microcirculation in the setting of cardiac arrest is largely unknown. Animal experiments have consistently revealed that global hemodynamics do not necessarily reflect microvascular perfusion. In addition, the time it takes for capillary blood flow to stop after the heart arrests is debated. Estimations range from 50 seconds to 5 mins, but data in humans are lacking. Aortic arch surgery frequently necessitates deep hypothermic circulatory arrest and subsequent selective antegrade cerebral perfusion. To elucidate microvascular behavior surrounding cessation of human circulation, we used sublingual microvascular imaging in this setting. Design: Prospective, observational study. Setting: Operating room of a large tertiary referral center for cardiac surgery. Patients: Seven patients undergoing elective aortic arch repair. Interventions: We used sidestream dark field imaging to study the sublingual microcirculation immediately before circulatory arrest, during circulatory arrest, and immediately after selective antegrade cerebral perfusion. Measurements and Main Results: Results are reported as mean (SD) unless indicated otherwise. Before circulatory arrest, perfused vessel density was 6.41 (1.18) for small ( 20 mu m) microvessels. Microvascular flow index was a median of 3.0 (interquartile range 3.0-3.0) for both vessel sizes. After circulatory arrest, there was no equilibration of arterial and venous blood pressure before onset of selective antegrade cerebral perfusion after 59 (17) secs (range, 40-80 secs). Flow in small microvessels came to a complete stop after 45 (9) secs (range, 34-57 secs) after transition to circulatory arrest. However, flow in larger microvessels did not completely stop before selective antegrade cerebral perfusion started. Selective antegrade cerebral perfusion restored microvascular flow, reaching precirculatory arrest levels after 45 (27) secs (range, 20-85 secs). Conclusions: In a controlled surgical setting, circulatory arrest in humans induces a complete sublingual small microvessel shutdown within 1 min. However, flow in larger microvessels persists. Selective antegrade cerebral perfusion was able to restore microvascular flow to precirculatory arrest levels within a similar timeframe. (Crit Care Med 2010; 38:1548-1553