511 research outputs found
Antenna with artificial magnetic conductor for wireless application
— This paper discussed the recent works on Artificial
Magnetic Conductor (AMC) with the antenna. Two different
application for antenna with AMC have been discussed. The
first application is the antenna with AMC that has been used for
RFID system to detect the metal object. Without incorporating
AMC with antenna the system cannot be detected. When the
AMC is attached with the RFID Tag antenna the system is back
to normal where longer distance is achieved. The second
application is used for flexible AMC using textile material for
signal transmission enhancement. Using two antennas for on
body application the system has been tested using AMC and
without AMC. It shows that the transmission is better when
there is an AMC attach to the body compared without AMC.
Index Terms — Artificial Magnetic Conductor, high
impedance surface, metamaterial, reflection phase
RISE-Based Integrated Motion Control of Autonomous Ground Vehicles With Asymptotic Prescribed Performance
This article investigates the integrated lane-keeping and roll control for autonomous ground vehicles (AGVs) considering the transient performance and system disturbances. The robust integral of the sign of error (RISE) control strategy is proposed to achieve the lane-keeping control purpose with rollover prevention, by guaranteeing the asymptotic stability of the closed-loop system, attenuating systematic disturbances, and maintaining the controlled states within the prescribed performance boundaries. Three contributions have been made in this article: 1) a new prescribed performance function (PPF) that does not require accurate initial errors is proposed to guarantee the tracking errors restricted within the predefined asymptotic boundaries; 2) a modified neural network (NN) estimator which requires fewer adaptively updated parameters is proposed to approximate the unknown vertical dynamics; and 3) the improved RISE control based on PPF is proposed to achieve the integrated control objective, which analytically guarantees both the controller continuity and closed-loop system asymptotic stability by integrating the signum error function. The overall system stability is proved with the Lyapunov function. The controller effectiveness and robustness are finally verified by comparative simulations using two representative driving maneuvers, based on the high-fidelity CarSim-Simulink simulation
A historical overview of Western medicine and health in Ghana in the twentieth century
Traditional therapy was dominant in Ghana. However, by the 19th to 20th centuries, scientific medicine had been fully introduced to the people of Ghana. There is a growing tendency in the research of medicine in Ghana. Some scholarly works had been published on Western medicine; however, all these works had not been brought together in analyzing the history of scientific medicine in Ghana. This work conducts an opportunistic historical overview of Western medicine and health in Ghana through the twentieth century. This is to bring to light some scholarly literature on Western medicine in Ghana, of which further research could be conducted. Some selected works that were relevant in the study of the history of western medical practices and health issues in Ghana were looked at
Optimal robust control of vehicle lateral stability using damped least-square backpropagation training of neural networks
Multiple molecular markers MAGE-1, MAGE-3 and AFP mRNAs expression nested PCR assay for sensitive and specific detection of circulating hepatoma cells: Enhanced detection of hepatocellular carcinoma
Hepatocellular Carcinoma is a multifactorial, multistep and complex process. Its prognosis is poor and early diagnosis and monitoring of metastasis of HCC is of utmost importance. Circulating alpha-fetoprotien mRNA has been proposed as a marker of HCC cells disseminatedinto the circulation but the specificity of this molecular marker and its correlation with the main HCC clinico-pathological parameters remain controversial. In recent years; several different multi-marker assays have been developed for the detection of hepatoma cells in the peripheral bloodof patients with HCC. In this study 58 patients and 15 matched healthy volunteers were included; the patients were divided into three groups; group A: patients with primary HCC (n =32), group B: patients withcirrhosis with no evidence of HCC (n= 12), group C: patients with metastatic cancer in liver (n= 14). Group D: 15 healthy volunteers age and sex matched. The staging of HCC was carried out according to the Tumor/Node/Metastasis (TNM) classification. Peripheral blood samples were obtained from all subjects; MAGE-1 and MAGE-3 and AFP mRNAs were detected by nested RT-PCR. The positive rates of MAGE-1, MAGE-3 and AFP mRNAs were 18/32 (56.3%), 15/32 (46.9%) and 19/32 (59.4%) respectively in the primary HCC patients. In the cirrhotic group only 4/12 (33.3%) patients were positive for AFP mRNA, whereas in the metastatic group 5/14 (35.7%) and 4/14 (28.6%) were positive to MAGE-1 and MAGE-3 mRNAs respectively. MAGE-1 and MAGE-3 mRNAs were correlated with TNM clinical stages; tumor number and tumor size (p<0.05).Our results indicate that a multi-marker nested RT-PCR assay with cancer-specific markers such as MAGE-1 and MAGE-3 in combination with a hepatocyte-specific AFP marker may be a promising diagnostic tool for monitoring hepatocellular carcinoma patients. Nested PCR exhibits highersensitivity, stronger specificity and lower false-positive occurrence as compared to single RT
HAMILTONIAN-BASED FREQUENCY-AMPLITUDE FORMULATION FOR NONLINEAR OSCILLATORS
Complex mechanical systems usually include nonlinear interactions between their components which can be modeled by nonlinear equations describing the sophisticated motion of the system. In order to interpret the nonlinear dynamics of these systems, it is necessary to compute more precisely their nonlinear frequencies. The nonlinear vibration process of a conservative oscillator always follows the law of energy conservation. A variational formulation is constructed and its Hamiltonian invariant is obtained. This paper suggests a Hamiltonian-based formulation to quickly determine the frequency property of the nonlinear oscillator. An example is given to explicate the solution process
Biochemical and Molecular Mechanisms of Folate Transport in Rat Pancreas; Interference with Ethanol Ingestion
Folic acid is an essential nutrient that is required for one-carbon biosynthetic processes and for methylation of biomolecules. Deficiency of this micronutrient leads to disturbances in normal physiology of cell. Chronic alcoholism is well known to be associated with folate deficiency which is due, in part to folate malabsorption. The present study deals with the mechanistic insights of reduced folate absorption in pancreas during chronic alcoholism. Male Wistar rats were fed 1 g/kg body weight/day ethanol (20% solution) orally for 3 months and the mechanisms of alcohol associated reduced folate uptake was studied in pancreas. The folate transport system in the pancreatic plasma membrane (PPM) was found to be acidic pH dependent one. The transporters proton coupled folate transporter (PCFT) and reduced folate carrier (RFC) are involved in folate uptake across PPM. The folate transporters were found to be associated with lipid raft microdomain of the PPM. Ethanol ingestion decreased the folate transport by reducing the levels of folate transporter molecules in lipid rafts at the PPM. The decreased transport efficiency of the PPM was reflected as reduced folate levels in pancreas. The chronic ethanol ingestion led to decreased pancreatic folate uptake. The decreased levels of PCFT and RFC expression in rat PPM were due to decreased association of these proteins with lipid rafts (LR) at the PPM
Twin pregnancy following sirolimus therapy in lymphangioleiomyomatosis
Lymphangioleiomyomatosis (LAM) is an orphan cystic lung disease which can occur
sporadically or in association with tuberous sclerosis complex (TSC). We report
a 26-year-old woman diagnosed with forme fruste of LAM, who presented with
bilateral pneumothoraces requiring both surgical and medical pleurodesis. Clinical
examination and investigations revealed hepatic and renal angiomyolipomas, a left retinal hamartoma, subcortical tubers and subependymal nodules in the brain
as well as diffuse bilateral thin-walled lung cysts of varying sizes bilaterally. The
histopathological examination (HPE) of the lung biopsy confirmed LAM. She was
treated with 12 months of sirolimus with sustained effects on lung function and
cystic lung lesions. Eight months post cessation of sirolimus, she conceived and
delivered twins at 30 weeks. We describe the efficacy and safety of sirolimus and
the successful twin pregnancy in a patient with LAM. This case highlights that
treatment with sirolimus and surgical and medical pleurodesis was successful in
preventing any further worsening of lung function
Variation over time of the Perez calibration algorithm for ground-based spectrometer
A spectrometer is likely to perform as expected over a period of time if calibrated with suitable method. This paper aims to study the variation of the Perez calibration algorithm over time for a spectrometer. The study was carried out for six months from July to August 2012 and January–April 2013. The measurements were recorded for every minute interval from 8.30 a.m. to 4.30 p.m. in three locations in Kota Kinabalu, Sabah, Malaysia. Monthly calibration constants for eight wavelengths were determined for the Perez model using improved Langley method. When only wavelengths which are close to 500 nm (460, 500, 540, 580, and 620 nm) were engaged, the variations over time of the Perez calibration constants were consistent over time (F = 1:381, p = 0:273). This is similar to the previous ?nding on the Du Mortier algorithm
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