187 research outputs found
A Novel Blended State Estimated Adaptive Controller for Voltage and Current Control of Microgrid against Unknown Noise
© 2013 IEEE. In this study, a novel blended state estimated adaptive controller is designed for voltage and current control of microgrid against unknown noise. The core feature of the microgrid (MG) is its ability to integrate more than one distributed energy resource into the main grid. The state of a microgrid may deteriorate due to many reasons, for example malicious cyber-attacks, disturbances, packet losses, etc. Therefore, it is necessary to achieve the true state of the system to enhance the control requirement and automation of the microgrid. To achieve the true state of a microgrid, this study proposes the use of an algorithm based on the unscented kalman filter (UKF). The proposed state estimator technique is developed using an unscented-transformation and sigma-points measurement technique capable of minimizing the mean and covariance of a nonlinear cost function to estimate the true state of a single-phase, three-phase single-source and three-phase multi-source microgrid system. The advantage of the proposed estimator over using extended kalman filter (EKF) is investigated in simulations. The results demonstrate that the use of the UKF estimator produces a superior estimation of the system compared with the use of the EKF. An adaptive PID controller is also developed and used in system conjunction with the estimator to regulate its voltage and current against the number of loads. Deviation in load parameters hamper the function of the MG system. The performance of the developed controller is also evaluated against number of loads. Results indicate the controller provides a more stable and high-tracking performance with the inclusion of the UKF in the system
Effects of nilotinib on leukaemia cells using vibrational microspectroscopy and cell cloning
Over the last few years, both synchrotron-based FTIR (S-FTIR) and Raman microspectroscopies have helped to better understand the effects of drugs on cancer cells. However, cancer is a mixture of cells with different sensitivity/resistance to drugs. Furthermore, the effects of drugs on cells produce both chemical and morphological changes, the latter could affect the spectra of cells incubated with drugs. Here, we successfully cloned sensitive and resistant leukaemia cells to nilotinib, a drug used in the management of leukaemia. This allowed both the study of a more uniform population and the study of sensitive and resistant cells prior to the addition of the drug with both S-FTIR and Raman microspectroscopies. The incubation with nilotinib produced changes in the S-FTIR and Raman spectra of both sensitive and resistant clones to nilotinib. Principal component analysis was able to distinguish between cells incubated in the absence or presence of the drug, even in the case of resistant clones. The latter would confirm that the spectral differences between the so-called resistant clonal cells prior to and after adding a drug might reside on those more or less sensitive cells that have been able to remain alive when they were collected to be studied with S-FTIR or Raman microspectroscopies. The data presented here indicate that the methodology of cell cloning can be applied to different types of malignant cells. This should facilitate the identification of spectral biomarkers of sensitivity/resistance to drugs. The next step would be a better assessment of sensitivity/resistance of leukaemia cells from patients which could guide clinicians to better tailor treatments to each individual patient
Bioaccessibility and speciation of arsenic in children’s diets and health risk assessment of an endemic area in Bangladesh
This study determines the bioaccessibility of toxic and carcinogenic arsenic (As) in composite food samples and evaluates potential exposure from food intake in Bangladesh children. Total As (tAs), inorganic As (iAs) and bioaccessible As (BAs) in food composite samples consumed by children were compared between an exposed and a control group (based on As in drinking water). Total As concentrations in composite food samples of children exposed to mean As level of 331 µg/l in drinking and cooking water ranged from 586 to 1975 µg/kg, dry weight over 76 to 90 µg/kg in the unexposed group. Average iAs in food composites was 73.9% (range: 49.3 to 90.8%). The fraction of BAs using gastric and gastrointestinal phases was 91±13% and 98±11%, respectively. Daily intake of iAs in exposed group ranged from 0.41 to 6.38 µg per kg body weight (BW), which was much higher than the unexposed group (0.08-0.15 µg per kg BW). High iAs content and BAs in composite food samples indicated elevated risk to exposed children. Further research should include both adult and children using larger sample size to determine overall As exposure from food intake in Bangladesh, attention must be given to lowering of As in food
Strength development characteristics of concrete produced with blended cement using Ground Granulated Blast furnace Slag (GGBS) under various curing conditions
Genetic Biomarkers for ALS Disease in Transgenic SOD1G93A Mice
The pathophysiological mechanisms of both familial and sporadic Amyotrophic Lateral Sclerosis (ALS) are unknown, although growing evidence suggests that skeletal muscle tissue is a primary target of ALS toxicity. Skeletal muscle biopsies were performed on transgenic SOD1G93A mice, a mouse model of ALS, to determine genetic biomarkers of disease longevity. Mice were anesthetized with isoflurane, and three biopsy samples were obtained per animal at the three main stages of the disease. Transcriptional expression levels of seventeen genes, Ankrd1, Calm1, Col19a1, Fbxo32, Gsr, Impa1, Mef2c, Mt2, Myf5, Myod1, Myog, Nnt, Nogo A, Pax7, Rrad, Sln and Snx10, were tested in each muscle biopsy sample. Total RNA was extracted using TRIzol Reagent according to the manufacturer's protocol, and variations in gene expression were assayed by real-time PCR for all of the samples. The Pearson correlation coefficient was used to determine the linear correlation between transcriptional expression levels throughout disease progression and longevity. Consistent with the results obtained from total skeletal muscle of transgenic SOD1G93A mice and 74-day-old denervated mice, five genes (Mef2c, Gsr, Col19a1, Calm1 and Snx10) could be considered potential genetic biomarkers of longevity in transgenic SOD1G93A mice. These results are important because they may lead to the exploration of previously unexamined tissues in the search for new disease biomarkers and even to the application of these findings in human studies
Polymorphisms of TP53 codon 72 with breast carcinoma risk: evidence from 12226 cases and 10782 controls
<p>Abstract</p> <p>Background</p> <p>Previously, TP53 codon 72 polymorphisms have been implicated as risk factors for various cancers. A number of studies have conducted on the association of TP53 codon 72 polymorphisms with susceptibility to breast carcinoma and have yielded inconclusive results. The aim of the present study was to derive a more precise estimation of the relationship.</p> <p>Methods</p> <p>We conducted a search in the Medline, EMBASE, OVID, Sciencedirect, and Chinese National Knowledge Infrastructure (CNKI) without a language limitation, covering all papers published up to Jan 2009. The associated literature was acquired through deliberate searching and selected based on the established inclusion criteria for publications.</p> <p>Results</p> <p>A total of seventeen case-control studies, including 12226 cases and 10782 controls, met the included criteria and thus were selected. Ultimately, the relevant data were extracted and further analyzed using systematic meta-analyses. Overall, no associations of TP53 codon 72 polymorphisms with breast carcinoma were observed (for Arg/Arg vs Pro/Pro: OR = 1.20; 95%CI = 0.96–1.50; for dominant model: OR = 1.12; 95%CI = 0.96–1.32; for recessive model: OR = 1.13; 95%CI = 0.98–1.31). In the subgroup analysis by ethnicity, statistically similar results were obtained when the data were stratified as Asians, Caucasians and Africans.</p> <p>Conclusion</p> <p>Collectively, the results of the present study suggest that <it>TP53 codon 72 </it>polymorphisms might not be a low-penetrant risk factor for developing breast carcinoma.</p
Pericardial Patch Angioplasty Heals via an Ephrin-B2 and CD34 Positive Cell Mediated Mechanism
Pericardial patches are commonly used in vascular surgery to close arteriotomies. The mechanism of early healing after patch implantation is still not well defined. We used a rat aortic patch model to assess pericardial patch healing and examined Ephrin-B2, a marker of arterial identity, expression within the post-implantation patch. We also determined whether endothelial progenitor cells (EPC) are associated with early patch healing in the arterial environment.Wistar rats (200-250 grams) underwent infrarenal aortic arteriotomy and then closure via bovine or porcine pericardial patch angioplasty. Control groups included subcutaneously implanted patches. Patches were harvested at 0-30 days and analyzed by histology, immunohistochemistry, immunofluorescence and Western blot as well as quantitative PCR.Prior to implantation, pericardial patches are largely composed of collagen and are acellular. Following arterial implantation, increasing numbers of CD68-positive cells as well as Ephrin-B2 and CD34 dual-positive cells are found within both bovine and porcine pericardial patches, whereas the infiltrating cells are negative for vWF and α-actin. Porcine patches have a luminal monolayer of cells at day 7, compared to bovine patches that have fewer luminal cells. Subcutaneously implanted patches do not attract Ephrin-B2/CD34-positive cells. By day 30, both bovine and porcine pericardial patches develop a neointima that contains Ephrin-B2, CD34, and VEGFR2-positive cells.Both CD68-positive and Ephrin-B2 and CD34 dual-positive cells infiltrate the pericardial patch early after implantation. Arteriotomy closure via pericardial patch angioplasty shows patch adaptation to the arterial environment that may involve a foreign body response as well as localization of EPC. Arterial remodeling of pericardial patches support endothelialization and may represent a paradigm of healing of scaffolds used for tissue engineering
The Influence of Incorporating Plastic within Concrete and the Potential Use of Microwave Curing; A Review
In recent decades, researchers have used plastic to replace natural aggregates (NAs), or as filler and fibre within the concrete. This particular paper puts forward a review that gives comprehensive consideration to the properties and drawbacks, of concrete that contains plastic. As such, it may be hypothesised that poor bond capacity and higher air content due to inclusion of plastic aggregate (PA) within concrete are the predominant factors that reduce the properties in terms of mechanics and durability. In that regard, this study has put forward a new method of curing using microwave irradiation for improvement with respect to those factors. So, that there can be further improvement with regard to overall durability with respect to advanced chemical and hydrophobic resistivity and enhanced performance for conventional concrete with respect to bonding and ductility
Utilization of antenatal ultrasound scan and implications for caesarean section: a cross-sectional study in rural Eastern China
<p>Abstract</p> <p>Background</p> <p>Antenatal ultrasound scan is a widely accepted component of antenatal care. Studies have looked at the relationship between ultrasound scanning and caesarean section (CS) in certain groups of women in China. However, there are limited data on the utilization of antenatal ultrasound scanning in the general population, including its association with CS. The purpose of this study is to describe the utilization of antenatal ultrasound screening in rural Eastern China and to explore the association between antenatal ultrasound scan and uptake of CS.</p> <p>Methods</p> <p>Based on a cluster randomized sample, a total of 2326 women with childbirth participated in the study. A household survey was conducted to collect socio-economic information, obstetric history and utilization of maternal health services.</p> <p>Results</p> <p>Coverage of antenatal care was 96.8% (2251/2326). During antenatal care, 96.1% (2164/2251) women received ultrasound screening and the reported average number was 2.55. 46.8% women received at least 3 ultrasound scans and the maximum number reached 11. The CS rate was found to be 54.8% (1275/2326). After adjusting for socio-demographic and clinical variables, it showed a statistically significant association between antenatal ultrasound scans and uptake of CS by multivariate logistic regression model. High husband education level, high maternal age, having previous adverse pregnant outcome and pregnancy complications during the index pregnancy were also found to be risk factors of choosing a CS.</p> <p>Conclusions</p> <p>A high use of antenatal ultrasound scan in rural Eastern China is found and is influenced by socio-demographic and clinical factors. Evidence-based guidelines for antenatal ultrasound scans need to be developed and disseminated to clinicians including physicians, nurses and sonographers. Guidance about the appropriate use of ultrasound scans should also be shared with women in order to discourage unreasonable expectations and demands. It is important to monitor the use of antenatal ultrasound scan as well as the indications for caesarean section in rural China.</p
Surgical trial in traumatic intracerebral hemorrhage (STITCH(Trauma)): study protocol for a randomized controlled trial
- …