6,879 research outputs found
Dynamic analysis of ground steering response of aircraft with electric taxi system
To provide taxi capability without the use of engines or tractor, electric landing gear drive is considered as a potential system add-on. Driving torque and nose wheel steering angle controller are established which are verified by civil aircraft examples. Quasi-steady method is applied to calculate tire forces and moments. The ground steering response of aircraft is simulated, and then different taxi conditions including powered nose wheel mode and powered main wheel mode are compared. Two conclusions are obtained: Electric taxi system helps the aircraft turn on the spot and the turning radius is smaller than the aircraft using engines; differential powered main wheel mode has the minimum turning radius while turning-circle with uniform velocity, and it has smaller difference between two vertical loads of main landing gear than powered nose wheel mode
Analysis of Tumbling Motions by Combining Telemetry Data and Radio Signal
The pointing accuracy and stabilization property of the payload of a satellite depends on performance of attitude determination and control system (ADCS). An essential role of the ADCS is to stabilize the spacecraft in early operation stage and in the presence of anomalies. During this stage, the satellite may be subject to tumbling and a high-reliability method is deemed important to recover the satellite from this stage into its normal operation stage. In the paper, the use of magnetometer data and radio signal characteristics is investigated with the goal of determining the satellite tumbling rate confidently. The proposed method is applied to the PHOENIX CubeSat, which is a CubeSat that is developed by National Cheng Kung University, Taiwan as a part of the QB50 project, at its early orbit stage
Health Numeracy Confidence among Racial/ Ethnica Minorities in HINTS 2007: Sociodemographic, Attitudinal, and Knowledge Correlates
Health numeracy skills help people interpret health risks, and make effective medical decisions. Lower health numeracy confidence was observed for blacks and Hispanic groups than whites. Little is known about the important factors that explain racial differences in health numeracy confidence. For this study, we used a nationally representative, cross-sectional data sample of 4,610 U.S. adults from the National Cancer Institute’s 2007 Health Information National Trends Survey. Bivariate (Chi-squares) and multiple logistic regression analyses were conducted to identify the contribution factors that predict health numeracy confidence.Non-linear Fairlie decompositions were used to quantify the factor contributions to racial differences in health numeracy confidence. The priority rankings of the important factors to explain the health numeracy confidence racial and ethnic disparities are different depending on the particular racial and ethnic group. Diverse, culturally appropriate approaches are needed to improve numeracy confidence for specific racial and ethnic groups
Complex roles ankyrin-1 plays in malaria infections
Despite the numerous interventions employed in the past few
decades, malaria remains one of the most lethal diseases
affecting millions of people worldwide. This is partly due to the
emergence of resistance to the current parasite-targeted
antimalarials. In contrast, erythrocytic genetic mutations have
been conferring malaria protection in humans for thousands of
years without losing their effectiveness. This presents a new
therapeutic approach to mimic these genetic mutations to treat
malaria, known as host-directed therapy (HDT), which requires
further understanding of host-parasite interactions to identify
potential HDT drug targets.
One such HDT target is the erythrocytic cytoskeleton, which
parasites rely on for their survival. Ankyrin-1 (Ank-1) is one of
erythrocytic cytoskeleton proteins, which has been associated
with hereditary spherocytosis (HS) in humans. This thesis
investigates the roles of Ank-1 in malaria infections using mouse
models and blood from HS patients. Mice with Ank-1 mutations were
found to exhibit phenotypes similar to human HS patients and are
protected against malaria via multiple mechanisms, suggesting
that Ank-1 plays a complex role in malaria infections. These
mechanisms are heavily influenced by the nature of Ank-1
mutations, which is further confirmed in human HS erythrocytes.
This thesis also explores the possibility of using the
ankyrin-spectrin interaction as a HDT target. Results show that
the disruption of this interaction has little effect on the
health of the mice, while conferring significant resistance
towards malaria, thus enabling the use of high throughput
screening (HTS) for drug discovery.
To summarise, this thesis highlights the complex interactions
between the erythrocyte cytoskeleton and malarial parasites, as
well as providing insights into the heterogeneous protective role
of Ank-1 in mediating malaria resistance. It also raises the
possibility of using erythrocytic cytoskeletal proteins as HDT
drug targets, which could potentially yield novel therapies for
malaria in the future
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