ABSTRACT
Ultrasonic computed tomography based on back scattering theory is the most powerful and accurate tool in ultrasound based imaging approaches because it is capable of providing quantitative information about the imaged target and detects very small targets. The duple-frequency distorted Born iterative method (DF–DBIM), which uses density information along with sound contrast for imaging, is a promising approach for imaging targets at the level of biological tissues. With two frequencies f₁ (low) and f₂ (high) through Nf₁ and Nf₂ iterations respectively, this method is used to estimate target density along with sound contrast. The implications of duple-frequency fusion for the image reconstruction quality of density information along with sound contrast based ultrasound tomography have been analyzed in this paper. In this paper, we concentrate on the selection of parameters that is supposed to be the best to improve the reconstruction quality of ultrasound tomography. When there are restraints imposed on simulated scenarios to have control of the computational cost, the iteration number Nf₁ is determined resulting in giving the best performance. The DF–DBIM is only effective if there are a moderate number of iterations, transmitters and receivers. In case that the number of transducers is either too large or too small, a result of reconstruction which is better than that of the single frequency approach is not produced by the implementation of DF–DBIM. A fixed sum N(iter) of Nf₁ and Nf₂ was given, the investigation of simulation results shows that the best value of Nf₁ is [N(iter)/2 − 1]. The error, when applying this way of choosing the parameters, will be normalized with the reduction of 56.11%, compared to use single frequency as used in the conventional DBIM method. The target density along with sound contrast is used to image targets in this paper. It is a fact that low-frequency offers fine convergence, and high-frequency offers fine spatial resolution. Wherefore, this technique can effectively expand DBIM's applicability to the problem of biological tissue reconstruction. Thanks to the usage of empirical data, this work will be further developed prior to its application in reality.
Subject(s)
Image Processing, Computer-Assisted , Methods , Transducers , Ultrasonics , UltrasonographyABSTRACT
<b>Background</b><BR> The Millennium Development Goals were put forth to strengthen maternal and child health, and because infectious disease has become a trend in the world, ensuring the quality and quantity of nursing is important. We report on a survey detailing the current status of legal frameworks and qualification systems in nursing in four countries: Cambodia, Lao People’s Democratic Republic (PDR), Myanmar, and Vietnam.<BR><b>Method</b><BR> We conducted a semi-structured interview with nursing administrative officers, and then we confirmed those information in their countries in 2012 and 2013. We categorized the existing nursing legal framework, nursing qualification systems, professional association and council.<BR><b>Results</b><BR> The King of Cambodia stipulated to a royal decree, which was established by the nursing council. In Lao PDR, following the Law on Health Care, two nursing and midwifery related regulations were developed. The Union of Myanmar enacted the Nurse and Midwife Law. In Vietnam following the Law on Medical Examination and Treatment, two Circulars were issued by the Ministry of Health to regulate the scope of practices and norms. We report on the current situation of the qualification and registration systems for nursing of each country. In addition, the development of qualifications and regulations should be reported based on the ASEAN Mutual Recognition Agreement (MRA).<BR><b>Conclusion</b><BR> We conducted a comparison of four countries to ensure the quality of nursing. A challenge for the future is compliance and dissemination of the laws and regulations that have been developed. ASEAN MRA has become a driving force for improvement of these legal systems.
ABSTRACT
Aedes albopictus C6/36 cells are susceptible to Dengue virus. The C6/36 cell line was infected with type 1 Dengue virus (DEN 1). At different time after these cells infected, morphological observations with electron microscope were conducted with super thin slicing method and the ultrastructural characteristics of DEN 1 virus in infected cells were recorded.