Role of Notch1 in Cardiac Cell Differentiation and Migration: A Dissertation

The cardiac conduction system is responsible for maintaining and orchestrating the rhythmic contractions of the heart. Results from lineage tracing studies indicate that precursor cells in the ventricles give rise to both cardiac muscle and conduction cells. Using chick embryonic hearts, we have found that Notch signaling plays an important role in the differentiation of cardiac muscle and conduction cell lineages in the ventricles. Notch1 expression coincides with a conduction marker at early stages of conduction system development. Mis-expression of constitutively active Notch1 (NIC) in early heart tubes exhibited multiple effects on cardiac cell differentiation. Cells expressing NIC had a significant decrease in the expression of cardiac muscle markers, but an increase in the expression of conduction cell markers. Loss-of-function studies further support that Notch1 signaling is important for the differentiation of these cardiac cell types. Functional electrophysiology studies show that the expression of constitutively active Notch1 resulted in abnormalities in ventricular conduction pathway patterns. During cardiogenesis, groups of myocardial cells become separated from each other, and migrate to form the trabeculae. These finger-like projections found within the ventricular chamber coalesce to generate the muscular portions of the interventricular septum, the thickened myocardium, and future sites of the conduction system. We have found that Notch signaling regulates the migration of cardiac cells during cardiogenesis. Over-expression of constitutively active Notch causes cells to localize more centrally within the heart, while loss-of-Notch function results in cells distributed within the periphery of the heart. Staining of heart sections shows that Notch signaling regulates the expression of N-cadherin, the predominant adhesion molecule in cardiomyocytes. We find that the effects of Notch on cell migration are two-fold: delamination and cell motility. Time-lapse studies demonstrate that Notch signaling increases cell motility, but does not affect speed or directionality of migration. Furthermore, we find that the effects of Notch on cell migration is independent of its effects on differentiation

Asymptotic Equivalence of Triangular Differential Equations in Hilbert Spaces

In this article, we study conditions for the asymptotic equivalence of differential equations in Hilbert spaces. We also discuss the relationship between the properties of solutions of differential equations of triangular form and those of truncated differential equations.Вивчено умови асимптотичної еквівалентності диференціальних рівнянь у гільбертових просторах. Розглянуто також зв'язок між властивостями розв'язків диференціальних рівнянь трикутної форми та неповних диференціальних рівнянь

A Molecular Line Survey of the Carbon-Rich Proto-Planetary Nebula AFGL 2688 in the 3mm and 1.3mm Windows

We present a spectral line survey of the proto-planetary nebula AFGL 2688 in the frequency ranges of 71-111 GHz, 157-160 GHz, and 218-267 GHz using the Arizona Radio Observatory 12m telescope and the Heinrich Hertz Submillimeter Telescope. A total of 143 individual spectral features associated with 32 different molecular species and isotopologues were identified. The molecules C3H, CH3CN, H2CO, H2CS, and HCO+ were detected for the first time in this object. By comparing the integrated line strengths of different transitions, we are able to determine the rotation temperatures, column densities, and fractional abundances of the detected molecules. The C, O, and N isotopic ratios in AFGL 2688 are compared with those in IRC+10216 and the Sun, and were found to be consistent with stellar nucleosynthesis theory. Through comparisons of molecular line strengths in asymptotic giant branch stars, proto-planetary nebulae, and planetary nebulae, we discuss the evolution in circumstellar chemistry in the late stages of evolution.Comment: 41 pages, 10 figures. Accepted for publication in Ap

APPLICATION OF GOOGLE EARTH SOFTWARE FOR TEACHING STUDENTS OF GEOGRAPHY EDUCATION AT AN GIANG UNIVERSITY, VIETNAM IN THE DIRECTION OF CAPACITY DEVELOPMENT

Applying information technology to teach students majoring in Geography pedagogy in a university environment in the direction of capacity development has contributed to improving training efficiency and quality. By analyzing and synthesizing documents combined with pedagogical experiments in the classroom, the article introduces Google Earth and the application of Google Earth to teach some geography modules for students of geography pedagogy at the An Giang University, Ho Chi Minh City National University, in the direction of capacity development. Through lessons and tests, assessments help students improve their general and specific competencies in Geography. In addition, the article also proposes some recommendations to allow lecturers to use Google Earth to teach Geography at universities more effectively.  Article visualizations

Improved Sensor Fault-Tolerant Control Technique Applied to Three-Phase Induction Motor Drive

An improved fault-tolerant control (FTC) method using mathematical functions is applied to the induction motor drive (IMD) against current sensors and speed encoder failures, which occur when the sensor is disconnected or completely damaged. The IMD with two current sensors and an encoder is speed controlled based on the field-oriented control (FOC) technique in regular operation. In this paper, an FTC unit is implemented in the FOC controller to detect and solve the sensor fault to increase the reliability of the speed control process. The measured stator currents and the feedback speed signal are integrated into the diagnosis algorithms to create a sensor fault-tolerant control function. Three diagnosis functions operating in a defined sequence are proposed for determining the health status of current and speed sensors. The FTC function performs isolation and replaces the faulty sensor signals with the proper estimated signals; then, the IMD will operate in the corresponding sensorless mode. Simulations will be performed to verify the accuracy and reliability of the proposed method under various sensor faults

A Framework for Task-Based Flipped Classroom in EFL Education in Vietnam

When it comes to language teaching in general education in Vietnam, there are many challenges for teachers to overcome. Such as time constraints, examination wash-back effects, students’ demotivation and students’ individualization causes of learning. Various innovative teaching methods and approaches have been applied to address these concerns, such as task-based language learning and flipped classrooms (FCs). However, each mode of teaching has its advantages and disadvantages. Due to this, it is essential to carefully examine the combination of TBLT and the flipped classroom (FC). This paper reviews the effects of the implementation of task-based language learning in the clipped classroom, discusses the integration of both teaching approaches, and suggests the applied model for English as a Foreign Language (EFL) education in Vietnam

Radon Mass Exhalation Rates of Selected Building Materials in Tanzania

This study aimed at determining the mass radon exhalation rate of Tanzania Portland cements and their raw materials for assessment of the radiological hazards due to use of those materials in residential construction. The radon mass exhalation rate was measured by closed chamber coupled with the Pylon AB5 Ô and varied from 0.3 to 13 %. The estimated indoor radon concentrations and annual effective dose for tightly closed standard room were within the safe limits of radon potential health hazards of 600 Bq m-3 for dwellings and 1500 Bq m-3 for workplaces recommended by International Commission on Radiological Protection (ICRP). Key words. Building materials; Radon mass exhalation rate; Annual effective dose; Radiological hazard; Tanzani

An Improved Current-Sensorless Method for Induction Motor Drives Applying Hysteresis Current Controller

A novel strategy based on the feed-forward field-oriented control (FOC) method is proposed for the Hysteresis Current technique to control the induction motor (IM) drive without current sensors (CSs). A control scheme is proposed to estimate stator currents from reference rotor flux, rotor flux angle, and state variables as a replacement for the feedback-signal of CSs used in the hysteresis current controller (HCC). Here the rotor flux angle component is extracted from the feed-forward FOC loop. MATLAB/Simulink is applied to implement the simulations under many different operating conditions. The simulation results demonstrated the feasibility of the proposed method to obtain high performance in controlling the IM drives without the current sensors

A robust diagnosis method for speed sensor fault based on stator currents in the RFOC induction motor drive

A valid diagnosis method for the speed sensor failure (SSF) is an essential requirement to ensure the reliability of Fault-Tolerant Control (FTC) models in induction motor drive (IMD) systems. Most recent researches have focused on directly comparing the measured and estimated rotor speed signal to detect the speed sensor fault. However, using that such estimated value in both the fault diagnosis and the controller reconfiguration phases leads to the insufficient performance of FTC modes. In this paper, a novel diagnosis-technique based on the stator current model combined with a confusion prevention condition is proposed to detect the failure states of the speed sensor in the IMD systems. It helps the FTC mode to separate between the diagnosis and reconfiguration phases against a speed sensor fault. This proposed SSF diagnosis method can also effectively apply for IMs’ applications at the low-speed range where the speed sensor signal often suffers from noise. MATLAB/Simulink software has been used to implement the simulations in various speed ranges. The achieved results have demonstrated the capability and effectiveness of the proposed SSF method against speed sensor faults

Static and vibration analysis of isotropic and functionally graded sandwich plates using an edge-based MITC3 finite elements

Static and vibration analysis of isotropic and functionally graded sandwich plates using a higher-order shear deformation theory is presented in this paper. Lagrangian functional is used to derive the equations of motion. The mixed interpolation of tensorial components (MITC) approach and edge-based-strain technique is used to solve problems. A MITC3 three-node triangle element with 7 degree-of-freedoms per nodes that only requires the C0-type continuity is developed. Numerical results for isotropic and functionally graded sandwich plates with different boundary conditions are proposed to validate the developed theory and to investigate effects of material distribution, side-to-thickness ratio, thickness ratio of layers and boundary conditions on the deflection, stresses and natural frequencies of the plates