394 research outputs found
Precision Position Control of Servo Systems Using Adaptive Back-Stepping and Recurrent Fuzzy Neural Networks
Effects of Cognitive Load Reduction Strategies and Prior Knowledge Levels on Comprehension of Speed Simulation, Cognitive Load, and Learning Efficiency for Fifth Grade Elementary Students
2007The purpose of this study was to investigate how cognitive load
reduction strategies and learners' prior knowledge affect on
comprehension of speed simulation, cognitive load, and learning
efficiency. It was randomly sampled 77 participants among fifth grade
students of an elementary school in Seoul city, Korea. They were
divided into two groups of prior knowledge (higher and lower) by two
different treatment groups (visual worked-example simulation group,
visual-auditory worked-example simulation group). Dependent variables
were comprehension of speed simulation, cognitive load, and learning
efficiency. Results showed that visual-auditory worked-example
simulation group was more efficient on comprehension of speed
simulation than visual worked-example simulation group, regardless of
learners prior knowledge level, so that less cognitive load led to higher
level of comprehension
Phase Current Measurement Method of Dual Inverter-Motor Drive System Using a Single DC Link Current Sensor
In recent years, electric propulsion systems have become widely, used and these systems have strict limits in volume and weight. Therefore, it is necessary to reduce the weight of the inverter-motor drive system. In a typical n inverter-motor drive system, at least 2n phase current sensors are required. In order to reduce the number of phase current sensors, this paper proposes a method for measuring phase current using n DC link current sensors in a 2n inverter-motor drive system. Two phase currents per inverter-motor system are measured during one period of the switching frequency using the pulse width modulation (PWM) shift method. However, since the measured phase current contains an error component in the average current, the error component was compensated for in order to obtain a current similar to the actual phase current by using the slope and dwell time of the phase current. The effectiveness of the proposed method is verified through experiments
Genome-Based Construction of the Metabolic Pathways of Orientia tsutsugamushi and Comparative Analysis within the Rickettsiales Order
Orientia tsutsugamushi, the causative agent of
scrub typhus, is an obligate intracellular
bacterium that belongs to the order of
Rickettsiales. Recently, we have reported that
O. tsutsugamushi has a unique
genomic structure, consisting of highly
repetitive sequences, and suggested that it may
provide valuable insight into the evolution of
intracellular bacteria. Here, we have used
genomic information to construct the major
metabolic pathways of
O. tsutsugamushi and performed a
comparative analysis of the metabolic genes and
pathways of O. tsutsugamushi
with other members of the Rickettsiales order.
While O. tsutsugamushi has the
largest genome among the members of this order,
mainly due to the presence of repeated
sequences, its metabolic pathways have been
highly streamlined. Overall, the metabolic
pathways of O. tsutsugamushi
were similar to Rickettsia but
there were notable differences in several
pathways including carbohydrate metabolism, the
TCA cycle, and the synthesis of cell wall
components as well as in the transport systems.
Our results will provide a useful guide to the
postgenomic analysis of
O. tsutsugamushi and lead
to a better understanding of the virulence and
physiology of this intracellular pathogen
Wearable, Ultrawide-Range, and Bending-Insensitive Pressure Sensor Based on Carbon Nanotube Network-Coated Porous Elastomer Sponges for Human Interface and Healthcare Devices
Flexible and wearable pressure sensors have attracted a tremendous amount of attention due to their wider applications in human interfaces and healthcare monitoring. However, achieving accurate pressure detection and stability against external stimuli (in particular, bending deformation) over a wide range of pressures from tactile to body weight levels is a great challenge. Here, we introduce an ultrawide-range, bending-insensitive, and flexible pressure sensor based on a carbon nanotube (CNT) network-coated thin porous elastomer sponge for use in human interface devices. The integration of the CNT networks into three-dimensional microporous elastomers provides high deformability and a large change in contact between the conductive CNT networks due to the presence of micropores, thereby improving the sensitivity compared with that obtained using CNT-embedded solid elastomers. As electrical pathways are continuously generated up to high compressive strain (∼80%), the pressure sensor shows an ultrawide pressure sensing range (10 Pa to 1.2 MPa) while maintaining favorable sensitivity (0.01–0.02 kPa–1) and linearity (R2 ∼ 0.98). Also, the pressure sensor exhibits excellent electromechanical stability and insensitivity to bending-induced deformations. Finally, we demonstrate that the pressure sensor can be applied in a flexible piano pad as an entertainment human interface device and a flexible foot insole as a wearable healthcare and gait monitoring device
Specific Radius Change of Quantum Dot inside the Lipid Bilayer by Charge Effect of Lipid Head-Group
We studied the quantum dot-liposome complex (QLC), which is the giant unilamellar vesicle with quantum dots (QDs) incorporated in its lipid bilayer. A spin coating method in conjunction with the electroformation technique yielded vesicles with highly homogeneous unilamellar structure. We observed QD size dependence of the QLC formation: QLCs form with blue, green and yellow-emission QD (core radius ~1.05 nm, 1.25 nm and 1.65 nm) but not with red-emission QD (core radius ~2.5 nm). In order to explain this size dependence, we made a simple model explaining the QD size effect on QLC formation in terms of the molecular packing parameter and the lipid conformational change. This model predicts that QDs below a certain critical size (radius ≈ 1.8 nm) can stably reside in a lipid bilayer of 4 - 5 nm in thickness for Egg-PC lipids. This is consistent with our previous experimental results. In the case of red-emission QD, QD-aggregations are only observed on the fluorescent microscopy instead of QLC. We expected that the reduction of packing parameter (P) would lead to the change of specific QD radius. This prediction could be verified by our experimental observation of the shift of the specific QD size by mixing DOPG
Toll-Like Receptor 4 Decoy, TOY, Attenuates Gram-Negative Bacterial Sepsis
Lipopolysaccharide (LPS), the Gram-negative bacterial outer membrane glycolipid, induces sepsis through its interaction with myeloid differentiation protein-2 (MD-2) and Toll-like receptor 4 (TLR4). To block interaction between LPS/MD-2 complex and TLR4, we designed and generated soluble fusion proteins capable of binding MD-2, dubbed TLR4 decoy receptor (TOY) using ‘the Hybrid leucine-rich repeats (LRR) technique’. TOY contains the MD-2 binding ectodomain of TLR4, the LRR motif of hagfish variable lymphocyte receptor (VLR), and the Fc domain of IgG1 to make it soluble, productive, and functional. TOY exhibited strong binding to MD-2, but not to the extracellular matrix (ECM), resulting in a favorable pharmacokinetic profile in vivo. TOY significantly extended the lifespan, when administered in either preventive or therapeutic manners, in both the LPS- and cecal ligation/puncture-induced sepsis models in mice. TOY markedly attenuated LPS-triggered NF-κB activation, secretion of proinflammatory cytokines, and thrombus formation in multiple organs. Taken together, the targeting strategy for sequestration of LPS/MD-2 complex using the decoy receptor TOY is effective in treating LPS- and bacteria-induced sepsis; furthermore, the strategy used in TOY development can be applied to the generation of other novel decoy receptor proteins
Role of Amphipathic Helix of a Herpesviral Protein in Membrane Deformation and T Cell Receptor Downregulation
Lipid rafts are membrane microdomains that function as platforms for signal transduction and membrane trafficking. Tyrosine kinase interacting protein (Tip) of T lymphotropic Herpesvirus saimiri (HVS) is targeted to lipid rafts in T cells and downregulates TCR and CD4 surface expression. Here, we report that the membrane-proximal amphipathic helix preceding Tip's transmembrane (TM) domain mediates lipid raft localization and membrane deformation. In turn, this motif directs Tip's lysosomal trafficking and selective TCR downregulation. The amphipathic helix binds to the negatively charged lipids and induces liposome tubulation, the TM domain mediates oligomerization, and cooperation of the membrane-proximal helix with the TM domain is sufficient for localization to lipid rafts and lysosomal compartments, especially the mutivesicular bodies. These findings suggest that the membrane-proximal amphipathic helix and TM domain provide HVS Tip with the unique ability to deform the cellular membranes in lipid rafts and to downregulate TCRs potentially through MVB formation
Orientia tsutsugamushi and Comparative Analysis within the Rickettsiales Order
Orientia tsutsugamushi, the causative agent of scrub typhus, is an obligate intracellular bacterium that belongs to the order of Rickettsiales. Recently, we have reported that O. tsutsugamushi has a unique genomic structure, consisting of highly repetitive sequences, and suggested that it may provide valuable insight into the evolution of intracellular bacteria. Here, we have used genomic information to construct the major metabolic pathways of O. tsutsugamushi and performed a comparative analysis of the metabolic genes and pathways of O. tsutsugamushi with other members of the Rickettsiales order. While O. tsutsugamushi has the largest genome among the members of this order, mainly due to the presence of repeated sequences, its metabolic pathways have been highly streamlined. Overall, the metabolic pathways of O. tsutsugamushi were similar to Rickettsia but there were notable differences in several pathways including carbohydrate metabolism, the TCA cycle, and the synthesis of cell wall components as well as in the transport systems. Our results will provide a useful guide to the postgenomic analysis of O. tsutsugamushi and lead to a better understanding of the virulence and physiology of this intracellular pathogen
- …