Development of an Actuator for an Airdropped Platform Landing System

This work presents an actuation system that aims at improving the maneuvering capability during the landing phase of the LAICAnSat platform. The LAICAnSat is a low-cost, modular platform for high altitude applications, such as remote sensing, telecommunications, research, development and innovation within the aerospace field. The landing system uses a ram-air parachute that is actuated by servo motors located on a pseudo 2U CubeSat platform. This platform differs from the actual CubeSat standard due to the actuation mechanisms on the outside of a 2U standard module. A brake lines actuator is responsible for the directional, speed and glide ratio control. The paper provides details of the design, realization and testing of the actuation system, which represent a first attempt in the development of an autonomous landing system for the LAICAnSat

Role of precombustion chamber design in feed-system coupled instabilities of hybrid rockets

Oxidizer feed-system coupled instabilities have been observed in several liquid and hybrid propellant rocket engines, although they are not likely to be catastrophic for the latter. However, severe pressure oscillation in hybrid rocket may result in a significant reduction in the performance of the propulsion system restricting the application of the technology. In this research, feed-system coupled instabilities were studied theoretically and experimentally for hybrid rocket engines. Two test campaigns were performed to investigate the effects of the precombustion chamber and oxidizer injector configurations on engine pressure oscillation. Then, an extended mathematical formulation (including the injector pressure drop, the precombustion chamber residence time, the gas residence time, and the combustion time lag) has been proposed. The investigation was based on a transfer function using the stability limit analysis and the root locus method. It has been found that the configuration of the precombustion chamber plays an important role in the nature of the feed-system coupled instabilities, and a correlation was proposed to predict the fundamental frequency based on the oxidizer precombustion chamber residence time. The work has shown that the precombustion chamber length and the oxidizer injection velocity are key parameters that affect the period of the pressure oscillations in hybrid engines subjected to feed-system coupled instabilities

An overview of the alfa crux cubesat mission for narrowband communication

The development and operation of a reliable voice and data communication systems in remote or difficult-to-reach areas is still a challenge in the modern world. In this framework, the mission Alfa Crux, based on a nanosatellite system under development at the Laboratory of Simulation and Control of Aerospace Systems (LODESTAR), University of Brasilia (UnB), Brazil, proposes the use of narrow bandwidth to create data and voice connections from low orbit. The Alfa Crux system aims at contributing to improve agricultural monitoring, water level controlling in rivers and reservoirs, as well as improving the communications technology between devices (M2M) and the Internet of Things (IoT), especially in remote regions where communication infrastructures on land are unreliable or cost prohibitive. The main problem addressed in this work concerns the development of a nanosatellite communication system based on UHF amateur radio frequency band. The choice of the frequency band is based on the fact that the use of narrowband in nanosatellite communication systems has relevant characteristics such as energy efficiency, spectrum, reliability, performance, safety, communication range, among others. This paper presents an overview of the communication architecture of the space mission of the Alfa Crux nanosatellite

Substrate-borne vibrations disrupt the mating behaviors of the neotropical brown stink bug, Euschistus heros: implications for pest management.

Made available in DSpace on 2018-05-24T00:52:47Z (GMT). No. of bitstreams: 1 10.1007s1034001809615.pdf: 942088 bytes, checksum: 49c966694e10345b8560655a6a4dc7c8 (MD5) Previous issue date: 2018-05-23bitstream/item/177582/1/10.1007-s10340-018-0961-5.pd

Impact of Vitamin D Supplementation on Arterial Vasomotion, Stiffness and Endothelial Biomarkers in Chronic Kidney Disease Patients

Background: Cardiovascular events are frequent and vascular endothelial function is abnormal in patients with chronic kidney disease (CKD). We demonstrated endothelial dysfunction with vitamin D deficiency in CKD patients; however the impact of cholecalciferol supplementation on vascular stiffness and vasomotor function, endothelial and bone biomarkers in CKD patients with low 25-hydroxy vitamin D [25(OH)D] is unknown, which this study investigated. Methods: We assessed non-diabetic patients with CKD stage 3/4, age 17–80 years and serum 25(OH)D ,75 nmol/L. Brachial artery Flow Mediated Dilation (FMD), Pulse Wave Velocity (PWV), Augmentation Index (AI) and circulating blood biomarkers were evaluated at baseline and at 16 weeks. Oral 300,000 units cholecalciferol was administered at baseline and 8-weeks. Results: Clinical characteristics of 26 patients were: age 50614 (mean61SD) years, eGFR 41611 ml/min/1.73 m2, males 73%, dyslipidaemia 36%, smokers 23% and hypertensives 87%. At 16-week serum 25(OH)D and calcium increased (43616 to 84629 nmol/L, p,0.001 and 2.3760.09 to 2.4260.09 mmol/L; p = 0.004, respectively) and parathyroid hormone decreased (10.868.6 to 7.464.4; p = 0.001). FMD improved from 3.163.3% to 6.163.7%, p = 0.001. Endothelial biomarker concentrations decreased: E-Selectin from 566662123 to 525662058 pg/mL; p = 0.032, ICAM-1, 3.4560.01 to 3.1061.04 ng/mL; p = 0.038 and VCAM-1, 54633 to 42633 ng/mL; p = 0.006. eGFR, BP, PWV, AI, hsCRP, von Willebrand factor and Fibroblast Growth Factor-23, remained unchanged. Conclusion: This study demonstrates for the first time improvement of endothelial vasomotor and secretory functions with vitamin D in CKD patients without significant adverse effects on arterial stiffness, serum calcium or FGF-23. Trial Registration: ClinicalTrials.gov NCT0200571

Non-reducible knee dislocation with interposition of the vastus medialis muscle

Irreducibility of the knee following complete dislocation is a rare event determined by the interposition of various capsulo-ligamentous structures in the joint space. Such cases often require urgent surgical treatment. We report the case of a healthy 70-year-old man with a sprain of the left knee that occurred after a sports trauma. The patient showed knee dislocation with multiple ligamentous injuries and articular block due to interposition of a portion of the vastus medialis muscle. After arthroscopic evaluation, we performed surgical treatment to free the muscle, regularize the medial meniscus and suture the posterior and medial capsule and ligaments; the cruciate ligaments were not treated. The most interesting aspect of the articular damage in this case was a wide detachment of the vastus medialis muscle with intra-articular dislocation. The decision to treat only the posterior lesions and allow the healing of the front ones by rehabilitation treatment was supported by full functional recovery and return to sports activity

miR-155 in the progression of lung fibrosis in systemic sclerosis

Background: MicroRNA (miRNA) control key elements of mRNA stability and likely contribute to the dysregulated lung gene expression observed in systemic sclerosis associated interstitial lung disease (SSc-ILD). We analyzed the miRNA gene expression of tissue and cells from patients with SSc-ILD. A chronic lung fibrotic murine model was used. Methods: RNA was isolated from lung tissue of 12 patients with SSc-ILD and 5 controls. High-resolution computed tomography (HRCT) was performed at baseline and 2-3 years after treatment. Lung fibroblasts and peripheral blood mononuclear cells (PBMC) were isolated from healthy controls and patients with SSc-ILD. miRNA and mRNA were analyzed by microarray, quantitative polymerase chain reaction, and/or Nanostring; pathway analysis was performed by DNA Intelligent Analysis (DIANA)-miRPath v2.0 software. Wild-type and miR-155 deficient (miR-155ko) mice were exposed to bleomycin. Results: Lung miRNA microarray data distinguished patients with SSc-ILD from healthy controls with 185 miRNA differentially expressed (q < 0.25). DIANA-miRPath revealed 57 Kyoto Encyclopedia of Genes and Genomes pathways related to the most dysregulated miRNA. miR-155 and miR-143 were strongly correlated with progression of the HRCT score. Lung fibroblasts only mildly expressed miR-155/miR-21 after several stimuli. miR-155 PBMC expression strongly correlated with lung function tests in SSc-ILD. miR-155ko mice developed milder lung fibrosis, survived longer, and weaker lung induction of several genes after bleomycin exposure compared to wild-type mice. Conclusions: miRNA are dysregulated in the lungs and PBMC of patients with SSc-ILD. Based on mRNA-miRNA interaction analysis and pathway tools, miRNA may play a role in the progression of the disease. Our findings suggest that targeting miR-155 might provide a novel therapeutic strategy for SSc-ILD

Enzymatic Shaving of the Tegument Surface of Live Schistosomes for Proteomic Analysis: A Rational Approach to Select Vaccine Candidates

Adult schistosome parasites can reside in the host bloodstream for decades surrounded by components of the immune system. It was originally proposed that their survival depended on the secretion of an inert bilayer, the membranocalyx, to protect the underlying plasma membrane from attack. We have investigated whether any proteins were exposed on the surface of live worms using incubation with selected hydrolases, in combination with mass spectrometry to identify released proteins. We show that a small number of parasite proteins are accessible to the enzymes and so could represent constituents of the membranocalyx. We also identified several proteins acquired by the parasite on contact with host cells. In addition, components of the cytolytic complement pathway were detected, but these appeared not to harm the worm, indicating that some of its own surface proteins could inhibit the lytic pathway. We suggest that, collectively, the ‘superficial’ parasite proteins may provide good candidates for a schistosome vaccine

Allergic Rhinitis and its Associated Co-Morbidities at Bugando Medical Centre in Northwestern Tanzania; A Prospective Review of 190 Cases.

Allergic rhinitis is one of the commonest atopic diseases which contribute to significant morbidity world wide while its epidemiology in Tanzania remains sparse. There was paucity of information regarding allergic rhinitis in our setting; therefore it was important to conduct this study to describe our experience on allergic rhinitis, associated co-morbidities and treatment outcome in patients attending Bugando Medical Centre. This was descriptive cross-sectional study involving all patients with a clinical diagnosis of allergic rhinitis at Bugando Medical Centre over a three-month period between June 2011 and August 2011. Data was collected using a pre-tested coded questionnaire and analyzed using SPSS statistical computer software version 17.0. A total of 190 patients were studied giving the prevalence of allergic rhinitis 14.7%. The median age of the patients was 8.5 years. The male to female ratio was 1:1. Adenoid hypertrophy, tonsillitis, hypertrophy of inferior turbinate, nasal polyps, otitis media and sinusitis were the most common co-morbidities affecting 92.6% of cases and were the major reason for attending hospital services. Sleep disturbance was common in children with adenoids hypertrophy (χ2 = 28.691, P = 0.000). Allergic conjunctivitis was found in 51.9%. The most common identified triggers were dust, strong perfume odors and cold weather (P < 0.05). Strong perfume odors affect female than males (χ2 = 4.583, P = 0.032). In this study family history of allergic rhinitis was not a significant risk factor (P =0.423). The majority of patients (68.8%) were treated surgically for allergic rhinitis co morbidities. Post operative complication and mortality rates were 2.9% and 1.6% respectively. The overall median duration of hospital stay of in-patients was 3 days (2 - 28 days). Most patients (98.4%) had satisfactory results at discharge. The study shows that allergic rhinitis is common in our settings representing 14.7% of all otorhinolaryngology and commonly affecting children and adolescent. Sufferers seek medical services due to co-morbidities of which combination of surgical and medical treatment was needed. High index of suspicions in diagnosing allergic rhinitis and early treatment is recommended