228 research outputs found
Development of Ground Penetrating Radar Hybrid System Using Vivaldi Antenna for Buried Object Detection
Ground penetrating radar (GPR) is categorized based on the number of antenna and modulation technique used for buried object detection. GPR systems that were often studied are the GPR of amplitude modulation and GPR of frequency modulation. Based on these two types of GPR system, the GPR of frequency modulation which is known as Stepped Frequency Continuous Wave (SFCW) is easy to be developed using only antenna and vector network analyzer (VNA). This study combined the Pulse modulation and SFCW GPR to form the GPR Hybrid. The combination was made in order to develop Pulse modulation GPR system of amplitude modulation GPR type using VNA. Discussion on this developed Hybrid GPR using the CST studio Suite 2014 software, included the design of a GPR antenna called the Vivaldi antenna of patch types, the design on simulation system of GPR Hybrid system, and the implementation of GPR Hybrid system using vector network analyzer. After the validation process, the developed GPR Hybrid system equipment was able to successfully detect a metal object that was buried in a wooden chamber containing dry sand
Highly efficient wearable CPW antenna enabled by EBG-FSS structure for medical body area network applications
A wearable fabric CPW antenna is presented for medical body area network (MBAN) applications at 2.4 GHz based on an electromagnetic bandgap design and frequency selective surface (EBG-FSS). Without EBG-FSS, the basic antenna has an omnidirectional radiation pattern, and when operated close to human tissue, the performance and efficiency degrade, and there is a high specific absorption rate. To overcome this problem, the antenna incorporates EBG-FSS, which reduces the backward radiation, with SAR reduced by 95%. The gain is improved to 6.55 dBi and the front-to-back ratio is enhanced by 13 dB compared to the basic antenna. The overall dimensions of the integrated design are 60×60×2.4 mm 3 . Simulation and experimental studies reveal that the antenna integrated with EBG-FSS can tolerate loading by human tissue as well as bending. Thus, the design is a good candidate for MBAN applications
Family presence during resuscitation: A randomised controlled trial of the impact of family presence
Introduction: This study was undertaken to determine effects on relatives of family presence in an emergency resuscitation room during resuscitation. Methods: This study was undertaken using a randomised controlled trial using survey methodology. The setting of the study was the emergency department of a major tertiary referral teaching hospital in Queensland. Participants were relatives over 18 years of age, related to patients meeting the inclusion criteria. Relatives were randomly assigned to the experimental or control group. The control group followed the established procedure of placement in the relatives' waiting room, while the experimental group was given the option to be present during the resuscitation with a supportive officer for assistance. Results: An association was found between those who were present (and their relative survived) and their belief that their presence was beneficial to the patient. Demographic data identified characteristics of the relatives. Conclusions: This work has identified that relatives find it beneficial to be present in the resuscitation room. Their presence helped with communication between staff and family, and helped relatives to cope with the situation
Synthesis and characterization of hypoxia-mimicking bioactive glasses for skeletal regeneration
The cellular response to hypoxia (low oxygen pressure) is vital for skeletal tissue development and regeneration. Numerous processes, including progenitor cell recruitment, differentiation and angiogenesis, are activated via the hypoxia pathway. Novel materials-based strategies designed to activate the hypoxia pathway are therefore of great interest for orthopaedic tissue engineering. Resorbable bioactive glasses (BGs) were developed to activate the hypoxia pathway by the controlled release of cobalt ions (at physiological relevant concentrations) whilst controlling BG apatite-forming ability. Two series of soda-lime-phosphosilicate glasses were synthesised with increasing concentrations of cobalt. Compositions were calculated to maintain constant network connectivity (2.13) by considering that cobalt is taking part in the network in the first series, and is acting as a network modifier in the second series. Mg2+ and Zn2+ were added to one of the Co2+-containing glasses to inhibit HCA formation. The presence of HCA formation is undesirable for the use of BG in soft tissues e. g. cartilage. Cobalt was present in both the silicate and phosphate phases of the BG. In addition, evidence was found that it plays a dual role in the silicate phase, entering the network as well as disrupting it as a network modifying oxide. Consistent with this dual role, the presence of cobalt in the BG was shown to decrease ion release. HCA formation was delayed with cobalt addition as well as incorporation of Mg2+ and Zn2+ into the BGs. Importantly, cobalt release was found to be proportional to cobalt content of the BGs enabling the controlled delivery of cobalt in therapeutically active doses
Remodeling of Retinal Fatty Acids in an Animal Model of Diabetes: A Decrease in Long-Chain Polyunsaturated Fatty Acids Is Associated With a Decrease in Fatty Acid Elongases Elovl2 and Elovl4
OBJECTIVE: The results of the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications cohort study revealed a strong association between dyslipidemia and the development of diabetic retinopathy. However, there are no experimental data on retinal fatty acid metabolism in diabetes. This study determined retinal-specific fatty acid metabolism in control and diabetic animals. RESEARCH DESIGN AND METHODS: Tissue gene and protein expression profiles were determined by quantitative RT-PCR and Western blot in control and streptozotocin-induced diabetic rats at 3-6 weeks of diabetes. Fatty acid profiles were assessed by reverse-phase high-performance liquid chromatography, and phospholipid analysis was performed by nano-electrospray ionization tandem mass spectrometry. RESULTS: We found a dramatic difference between retinal and liver elongase and desaturase profiles with high elongase and low desaturase gene expression in the retina compared with liver. Elovl4, an elongase expressed in the retina but not in the liver, showed the greatest expression level among retinal elongases, followed by Elovl2, Elovl1, and Elovl6. Importantly, early-stage diabetes induced a marked decrease in retinal expression levels of Elovl4, Elovl2, and Elovl6. Diabetes-induced downregulation of retinal elongases translated into a significant decrease in total retinal docosahexaenoic acid, as well as decreased incorporation of very-long-chain polyunsaturated fatty acids (PUFAs), particularly 32:6n3, into retinal phosphatidylcholine. This decrease in n3 PUFAs was coupled with inflammatory status in diabetic retina, reflected by an increase in gene expression of proinflammatory markers interleukin-6, vascular endothelial growth factor, and intercellular adhesion molecule-1. CONCLUSIONS: This is the first comprehensive study demonstrating diabetes-induced changes in retinal fatty acid metabolism. Normalization of retinal fatty acid levels by dietary means or/and modulating expression of elongases could represent a potential therapeutic target for diabetes-induced retinal inflammation
Fully fabric high impedance surface-enabled antenna for wearable medical applications
The compact and robust high-impedance surface (HIS) integrated with the antenna is designed to operate at a frequency of 2.45 GHz for wearable applications. They are made of highly flexible fabric material. The overall size is mm3 which equivalent to mm3. The value of using HIS lies in protecting the human body from harmful radiation and maintaining the performance of the antenna, which may be affected by the high conductivity of the human body. Besides, setting the antenna on the human body by itself detunes the frequency, but by adding HIS, it becomes robust and efficient for body loading and deformation. Integrated antenna with HIS demonstrates excellent performance, such as a gain of 7.47 dBi, efficiency of 71.8% and FBR of 10.8 dB. It also reduces the SAR below safety limits. The reduction is more than 95%. Therefore, the presented design was considered suitable for wearable applications. Further study was also performed to show the useful of placing antenna over HIS compared to the use of perfect electric conductor (PEC). The integrated design was also investigated with the worst case of varying the permittivity of body equivalent model which shows excellent performance in term of reflection coefficient and SAR levels. Hence, the integrated antenna with HIS is mechanically robust to human body tissue loading, and it is highly appropriate for body-worn applications
A Three-Way Comparison of Tuberculin Skin Testing, QuantiFERON-TB Gold and T-SPOT.TB in Children
BACKGROUND: There are limited data comparing the performance of the two commercially available interferon gamma (IFN-gamma) release assays (IGRAs) for the diagnosis of tuberculosis (TB) in children. We compared QuantiFERON-TB gold In Tube (QFT-IT), T-SPOT.TB and the tuberculin skin test (TST) in children at risk for latent TB infection or TB disease. METHODS AND FINDINGS: The results of both IGRAs were compared with diagnosis assigned by TST-based criteria and assessed in relation to TB contact history. Results from the TST and at least one assay were available for 96 of 100 children. Agreement between QFT-IT and T-SPOT.TB was high (93% agreement, kappa = 0.83). QFT-IT and T-SPOT.TB tests were positive in 8 (89%) and 9 (100%) children with suspected active TB disease. There was moderate agreement between TST and either QFT-IT (75%, kappa = 0.50) or T-SPOT.TB (75%, kappa = 0.51). Among 38 children with TST-defined latent TB infection, QFT-IT gold and T-SPOT.TB assays were positive in 47% and 39% respectively. Three TST-negative children were positive by at least one IGRA. Children with a TB contact were more likely than children without a TB contact to have a positive IGRA (QFT-IT LR 3.9; T-SPOT.TB LR 3.9) and a positive TST (LR 1.4). Multivariate linear regression analysis showed that the magnitude of both TST induration and IGRA IFN-gamma responses was significantly influenced by TB contact history, but only the TST was influenced by age. CONCLUSIONS: Although a high level of agreement between the IGRAs was observed, they are commonly discordant with the TST. The correct interpretation of a negative assay in a child with a positive skin test in clinical practice remains challenging and highlights the need for longitudinal studies to determine the negative predictive value of IGRAs
Estímulo no crescimento e na hidrólise de atp em raízes de alface tratadas com humatos de vermicomposto: ii - efeito da fonte de vermicomposto.
Um dos fatores mais limitantes para a produção de vermicomposto é a disponibilidade de esterco. Neste trabalho, foi avaliado o efeito da substituição parcial do esterco por bagaço de cana e por resíduos de leguminosa (Gliricidia sepium) na vermicompostagem sobre a qualidade do vermicomposto e sobre a bioatividade dos humatos, avaliadas por meio da análise do crescimento radicular e da atividade das bombas de H+ isoladas de raízes de alface. A substituição do esterco por bagaço de cana e por resíduos de leguminosas não acarretou prejuízo às características químicas dos vermicompostos. No entanto, os humatos isolados
dos diferentes vermicompostos apresentaram características químicas distintas,tais como: acidez e propriedades óticas distintas. Os humatos produzidos a partir de esterco de bovino e da mistura esterco bovino + bagaço proporcionaram maiores estímulos no crescimento radicular das plantas de alface, sendo os mais indicados para uso na forma solúvel. A inclusão de resíduos de leguminosas no processo de vermicompostagem produziu humatos sem efeito sobre o desenvolvimento das raízes de alface
- …