Time Synchronized High Performing Cluster-Based Routing Algorithm for Wireless Sensor Networks

In this paper, we investigated the data fusion routing algorithm and the time synchronization algorithm for the wireless sensor networks. First, we proposed a new data fusion routing algorithm - Low Energy Consumption Cluster-Based Routing Algorithm (LECCBRA). Simulation results show that the total energy can be effectively saved, and the balance in energy consumption between clusters can be achieved with LECCBRA, thus the network lifetime is extended. Second, we proposed a time synchronization algorithm - Clustering-based Time Synchronization (CBTS), which is suitable for LECCBRA. Performance analysis and simulation results show that the total energy can be effectively saved, and the accuracy can be improved

An estimation of the performance limits and improvement of dry cooling on trough solar thermal plants

A model of a fairly typical, but simplified, solar trough plant has been developed and simulated to determine its thermodynamic performance using the software GateCycle. The energy generation and cycle efficiency of the plant have been examined for the Las Vegas vicinity with conventional wet cooling and conventional dry cooling cases considered separately using this software. TMY2 data are used for this location for this purpose. Similarly, the same studies are carried out for ideal cooling systems as a compariSon It turned out that the ideal dry cooling system would significantly outperform the conventional wet cooling system, indicating the possibility of the dry cooling system being able to achieve increased performance levels with component improvements. Then an advanced circular-tube-circular-fin surface and a flattened-tube surface were applied to the air-cooled condenser and simulated. The results of the new models were compared with that of the default model

AN ESTIMATION OF THE PERFORMANCE LIMITS OF DRY COOLING ON TROUGH-TYPE SOLAR THERMAL PLANTS

ABSTRACT The southwestern US is an ideal location for solar power plants due to its abundant solar resource, while there is a difficulty in implementing wet cooling systems due to the shortage of water in this region. Dry cooling could be an excellent solution for this, if it could achieve a high efficiency and low cost as wet cooling. Some dry cooling systems are currently in operation, and investigations of their performance have been reported in the literature. This paper looks into the limits to the power production implicit in dry cooling, assuming that improvements might be made to the system components. Use of higher performance heat transfer surfaces is one such possible improvement. We have developed a model of a fairly typical, but simplified, solar trough plant, and simulated thermodynamic performance of this with the software Gatecycle. We have examined the power generation and cycle efficiency of the plant for the Las Vegas vicinity with conventional wet cooling and conventional dry cooling cases considered separately using this software. TMY2 data are used for this location for this purpose. Similarly, the same studies are carried out for "ideal" cooling systems as a comparison. We assumed that in the ideal dry cooling system, the condensing temperature is the ambient dry bulb temperature, and in the ideal wet cooling system, it is the ambient wet bulb temperature. It turned out that the ideal dry cooling system would significantly outperform the conventional wet cooling system, indicating the possibility of the dry cooling system being able to achieve increased performance levels with component improvements

Seroprevalence of Toxoplasma gondii in pregnant women and livestock in the mainland of China : a systematic review and hierarchical meta-analysis

Primary Toxoplasma gondii infection in pregnant women may result in abortion, stillbirth, or lifelong disabilities of the unborn child. One of the main transmission routes to humans is consumption of raw or undercooked meat containing T. gondii tissue cysts. We aim to determine and compare the regional distribution of T. gondii seroprevalence in pregnant women and meat-producing livestock in China through a systematic literature review. A total of 272 eligible publications were identified from Medline, Scopus, Embase and China National Knowledge Infrastructure. Apparent and true seroprevalence were analysed by region using a novel Bayesian hierarchical model that allowed incorporating sensitivity and specificity of the applied serological assays. The true seroprevalence of T. gondii in pregnant women was 5.0% or less in seven regions of China. The median of the regional true seroprevalences in pigs (24%) was significantly higher than in cattle (9.5%), but it was not significantly higher than in chickens (20%) and small ruminants (20%). This study represents the first use of a Bayesian hierarchical model to obtain regional true seroprevalence. These results, in combination with meat consumption data, can be used to better understand the contribution of meat-producing animals to human T. gondii infection in China

Web-based System Evolution in Model Driven Architecture

Abstract The complexity and size of commercial Web

A quantitative risk assessment for human Taenia solium exposure from home slaughtered pigs in European countries

Background: Taenia solium, a zoonotic tapeworm, is responsible for about a third of all preventable epilepsy human cases in endemic regions. In Europe, adequate biosecurity of pig housing and meat inspection practices have decreased the incidence of T. solium taeniosis and cysticercosis. Pigs slaughtered at home may have been raised in suboptimal biosecurity conditions and slaughtered without meat inspection. As a result, consumption of undercooked pork from home slaughtered pigs could pose a risk for exposure to T. solium. The aim of this study was to quantify the risk of human T. solium exposure from meat of home slaughtered pigs, in comparison to controlled slaughtered pigs, in European countries. A quantitative microbial risk assessment model (QMRA) was developed and porcine cysticercosis prevalence data, the percentage of home slaughtered pigs, meat inspection sensitivity, the cyst distribution in pork and pork consumption in five European countries, Bulgaria, Germany, Poland, Romania and Spain, were included as variables in the model. This was combined with literature about cooking habits to estimate the number of infected pork portions eaten per year in a country. Results: The results of the model showed a 13.83 times higher prevalence of contaminated pork portions from home slaughtered pigs than controlled slaughtered pigs. This difference is brought about by the higher prevalence of cysticercosis in pigs that are home raised and slaughtered. Meat inspection did not affect the higher exposure from pork that is home slaughtered. Cooking meat effectively lowered the risk of exposure to T. solium-infected pork. Conclusions: This QMRA showed that there is still a risk of obtaining an infection with T. solium due to consumption of pork, especially when pigs are reared and slaughtered at home, using data of five European countries that reported porcine cysticercosis cases. We propose systematic reporting of cysticercosis cases in slaughterhouses, and in addition molecularly confirming suspected cases to gain more insight into the presence of T. solium in pigs and the risk for humans in Europe. When more data become available, this QMRA model could be used to evaluate human exposure to T. solium in Europe and beyond

Senescent renal tubular epithelial cells activate fibroblasts by secreting Shh to promote the progression of diabetic kidney disease

IntroductionDiabetic kidney disease (DKD) is one of the complications of diabetes; however, the pathogenesis is not yet clear. A recent study has shown that senescence is associated with the course of DKD. In the present study, we explored whether senescent renal tubular cells promote renal tubulointerstitial fibrosis by secreting Sonic hedgehog (Shh) which mediates fibroblast activation and proliferation in DKD.MethodsA 36-week-old db/db mice model and the renal tubular epithelial cells were cultured in high glucose (HG, 60 mmol/L) medium for in vivo and in vitro experiments.ResultsCompared to db/m mice, blood glucose, microalbuminuria, serum creatinine, urea nitrogen, and UACR (microalbuminuria/urine creatinine) were markedly increased in db/db mice. Collagen III, monocyte chemoattractant protein-1 (MCP-1), and tumor necrosis factor-alpha (TNF-α) were also increased in db/db mice kidneys, suggesting fibrosis and inflammation in the organ. Moreover, the detection of SA-β-galactosidase (SA-β-Gal) showed that the activity of SA-β-Gal in the cytoplasm of renal tubular epithelial cells increased, and the cell cycle inhibition of the expression of senescence-related gene cell cycle inhibitor p16INK4A protein and p21 protein increased, indicating that renal fibrosis in db/db mice was accompanied by cell senescence. Furthermore, Shh is highly expressed in the injured renal tubules and in the kidney tissue of db/db mice, as detected by enzyme-linked immunosorbent assay (ELISA). The results of immunofluorescence staining showed increased positive staining for Shh in renal tubular epithelial cells of db/db mice and decreased positive staining for Lamin B1, but increased positive staining for γH2A.X in cells with high Shh expression; similar results were obtained in vitro. In addition, HG stimulated renal tubular epithelial cells to secrete Shh in the supernatant of the medium. D-gal treatment of renal tubular epithelial cells increased the protein levels of Shh and p21. We also found enhanced activation and proliferation of fibroblasts cultured with the supernatant of renal tubular epithelial cells stimulated by HG medium but the proliferative effect was significantly diminished when co-cultured with cyclopamine (CPN), an inhibitor of the Shh pathway.DiscussionIn conclusion, HG induces renal tubular epithelial cell senescence, and the secretion of senescence-associated proteins and Shh mediates inflammatory responses and fibroblast activation and proliferation, ultimately leading to renal fibrosis

Source attribution of human toxoplasmosis : A quantitative microbiological risk assessment approach

Toxoplasma gondii (T. gondii) is a protozoan parasite with a worldwide distribution. It can infect all warm-blooded animals, and is the causative agent of toxoplasmosis. The global disease burden of toxoplasmosis is substantial and therefore considered as a public health problem worldwide. Quantitative microbial risk assessment (QMRA) is a source attribution method, which aggregates all available data on different aspects to compare the importance of different sources of infection. This thesis focuses on the assessment of relative attribution of different meat products and soil to human T. gondii infection by using QMRA models. In chapter 1, the life cycle of T. gondii, source of human infection, and different source attribution methods are described. In chapter 2, an overview of existing mathematical models to study the transmission of T. gondii and their assessments of different control strategies is described. Due to the complicated life cycle of the parasite and the absence of field data, models do not always represent reality. In chapter 3, a study estimating the seroprevalence and associated risk factors in indoor-housed Dutch dairy goats to investigate whether a biosecurity intervention would be feasible for reducing the risk of toxoplasmosis in grazing animals is presented. The estimated low seroprevalence suggested that indoor housing seems reduce the exposure of goats to T. gondii. In chapter 4, a hierarchical meta-analysis was performed to estimate the adjusted seroprevalence in pregnant women and livestock in China. These results not only provided us accurate insight on T. gondii infection status in China, but also important data in the meat-borne QMRA model. In chapter 5, the QMRA model of meat-borne T. gondii infection in the Netherlands as described previously by Opsteegh et al. (2011) was updated. The updated model found that filet americain, spiced and smoked pork sausage and leg of mutton were the top three products associated with the highest number of predicted infections. In addition, salting had a great effect on T. gondii survival but does not necessarily inactive all T. gondii. The Dutch QMRA model was implemented for China in chapter 6. It identified pork as the main source of T. gondii infection, followed by poultry, small ruminants, ducks and cattle. Results from the QMRA models clearly show that the prevalence of T. gondii infection in livestock does not necessarily present an indication for the risk of infection or the importance of the different types of meat on a population level. In chapter 7, The risk associated with T. gondii exposure via soil intake in the Netherlands was estimated and a sensitive magnetic capture qPCR method was developed. Currently the model likely overestimates the risk of infection via soil, and several data gaps were identified. We recommend to collect specific data for different population groups in the future. In chapter 8, the values and limitations of the quantitative risk assessment approach for toxoplasmosis source attribution were discussed. The findings in this thesis can aid science-based decision-making on where to target interventions, thereby, in the end, reducing the disease burden of toxoplasmosis

Computer modelling of liquid crystal displays

This thesis describes research work in modelling 2-dimensional twisted nematic liquid crystal display devices. There are three salient aspects of this work; The first and more extensive is the development, implementation and testing of a new formulation for the dynamic modelling of these devices using a constant-charge assumption, which more accurately represents the case of thin-film-transistor (TFT)-driven devices. Based on a dynamic tensor formulation (to preserve the nematic symmetry) and a single elastic constant approximation, the mode is developed to simulate the TFT driven device switching by allowing the voltages to be connected to the pixel electrodes for only a line time duration (typically 15μs ~ 30μs) and then letting them float for the rest of the half frame time while the charge remains constant. The director and electric potential distributions are dynamically calculated using a combination of finite differences and finite element methods under given electrode configurations and boundary conditions. The capacitance matrix is determined using a perturbation technique, and this further allows the voltages on the pixel electrodes to be found during the drifting time. This method can predict the dynamic behaviour of such a device more accurately than earlier models using a direct (fixed voltage) driving scheme and can include the effect of external storage capacitors. The programs developed in this project include as a special case the direct driving situation, produce as results the dynamic responses of various physics properties such as pixel voltages, capacitances of all electrodes, tilt angles and transmittance of the cell etc., and can also reproduce flicker behaviour due to the DC bias. There is good agreement between predicted results and experimental observations. The second part of the work involves the theoretical derivation of a dynamic tensorial formulation for the liquid crystal behaviour, using three elastic constants. This derivation will be implemented outside this work and the resulting programs will give an even better modelling capability. In the third part, in order to have a better interpretation of viewing angle characteristic of the studied cells, the extended 2x2 Jones matrix approach has been further generalised to include arbitrary incident (polar and azimuthal) angles