1,440 research outputs found
5-3 FUTURE DIRECTION OF WELDING STRUCTURE PRODUCTION(Session 5 : Utilization of Computers,SIMAP'88 Proceedings of International Symposium on Strategy of Innovation in Materials Processing-New Challenge for the 21st Century-)
In vitro mutagenesis of Cymbidium La bell āAnna Belleā by Ī³-rays irradiation and oligochitosan interaction
The optimum media for multiplication of protocorm like bodies (PLBs) and shoot buds of Cymbidium La bell āAnna Belleā were studied in order to prepare the in vitro samples for irradiation. The values of LD50 (lethal dose of 50% samples) of PLBs, shoot buds and plantlets of tested Cymbidium after cultivation of 4 months were also determined about 35.0, 41.0 and 83.1 Gy, respectively. The addition of oligochitosan played as an very important trigger for promotion on the generation of shoot bud from PLBs after irradiation. The in vitro variations have been generated by Ī³-rays irradiation of PLBs with doses in range of 20 - 50 Gy. The highest mutant frequency (3.83ā°) of C. La bell was found by the irradiation of PLB samples at 30 Gy. The different properties of obtained in vitro variations compared to wild types were found to be chlorophyll, short leaves, long leaves, and violet pericardium variations. The genetic relationships among generated variant lines in M1V4 and wild type were analyzed using RAPD techniques
Method to extract multiple states in Fā-ATPase rotation experiments from jump distributions
A method is proposed for analyzing fast (10 Ī¼s) single-molecule rotation trajectories in Fā adenosinetriphosphatase (Fā-ATPase). This method is based on the distribution of jumps in the rotation angle that occur in the transitions during the steps between subsequent catalytic dwells. The method is complementary to the āstallingā technique devised by H. Noji et al. [Biophys. Rev. 9, 103ā118, 2017], and can reveal multiple states not directly detectable as steps. A bimodal distribution of jumps is observed at certain angles, due to the system being in either of 2 states at the same rotation angle. In this method, a multistate theory is used that takes into account a viscoelastic fluctuation of the imaging probe. Using an established sequence of 3 specific states, a theoretical profile of angular jumps is predicted, without adjustable parameters, that agrees with experiment for most of the angular range. Agreement can be achieved at all angles by assuming a fourth state with an ā¼10 Ī¼s lifetime and a dwell angle about 40Ā° after the adenosine 5ā²-triphosphate (ATP) binding dwell. The latter result suggests that the ATP binding in one Ī² subunit and the adenosine 5ā²-diphosphate (ADP) release from another Ī² subunit occur via a transient whose lifetime is ā¼10 Ī¼s and is about 6 orders of magnitude smaller than the lifetime for ADP release from a singly occupied Fā-ATPase. An internal consistency test is given by comparing 2 independent ways of obtaining the relaxation time of the probe. They agree and are ā¼15 Ī¼s
Hepatic cell mobilization for protection against ischemic myocardial injury
The heart is capable of activating protective mechanisms in response to ischemic injury to support myocardial survival and performance. These mechanisms have been recognized primarily in the ischemic heart, involving paracrine signaling processes. Here, we report a distant cardioprotective mechanism involving hepatic cell mobilization to the ischemic myocardium in response to experimental myocardial ischemiaāreperfusion (MI-R) injury. A parabiotic mouse model was generated by surgical skin-union of two mice and used to induce bilateral MI-R injury with unilateral hepatectomy, establishing concurrent gain- and loss-of-hepatic cell mobilization conditions. Hepatic cells, identified based on the cell-specific expression of enhanced YFP, were found in the ischemic myocardium of parabiotic mice with intact liver (0.2 Ā± 0.1%, 1.1 Ā± 0.3%, 2.7 Ā± 0.6, and 0.7 Ā± 0.4% at 1, 3, 5, and 10 days, respectively, in reference to the total cell nuclei), but not significantly in the ischemic myocardium of parabiotic mice with hepatectomy (0 Ā± 0%, 0.1 Ā± 0.1%, 0.3 Ā± 0.2%, and 0.08 Ā± 0.08% at the same time points). The mobilized hepatic cells were able to express and release trefoil factor 3 (TFF3), a protein mitigating MI-R injury as demonstrated in TFF3ā/ā mice (myocardium infarcts 17.6 Ā± 2.3%, 20.7 Ā± 2.6%, and 15.3 Ā± 3.8% at 1, 5, and 10 days, respectively) in reference to wildtype mice (11.7 Ā± 1.9%, 13.8 Ā± 2.3%, and 11.0 Ā± 1.8% at the same time points). These observations suggest that MI-R injury can induce hepatic cell mobilization to support myocardial survival by releasing TFF3
Interfacial Layers between Ion and Water Detected by Terahertz Spectroscopy
Dynamic fluctuations in hydrogen-bond network of water occur from femto- to
nano-second timescale and provides insights into structural/dynamical aspects
of water at ion-water interfaces. Employing terahertz spectroscopy assisted
with molecular dynamics simulations, we study aqueous chloride solutions of
five monovalent cations, namely, Li, Na, K, Rb and Cs. We show that ions modify
the behavior of surrounding water molecules and form interfacial layers of
water around them with physical properties distinct from that of bulk water.
Small cations with high charge densities influence the kinetics of water well
beyond the first solvation shell. At terahertz frequencies, we observe an
emergence of fast relaxation processes of water with their magnitude following
the ionic order Cs>Rb>K>Na>Li, revealing an enhanced population density of
weakly coordinated water at ion-water interface. The results shed light on the
structure breaking tendency of monovalent cations and provide insights into the
properties of ionic solutions at the molecular level
An integrated method for net-shape manufacturing components combining 3D additive manufacturing and compressive forming processes
Additive manufactured (AM) or 3D printed metallic components suffer poor and inconsistent mechanical properties due to the presence of a large number of micro-voids, residual stress and microstructure inhomogeneity. To overcome these problems, a new forming process has been proposed, which effectively combines AM and compressive forming. The aim of this study is to prove the feasibility of this newly proposed method by providing preliminary results. Thus, we compared the tensile performance of hot-forged additive manufactured stainless steel 316L samples to none-hot-forged additive manufactured ones. Significant improvement in mechanical properties has been found in the tensile tests as well hardness test. In addition, our EBSD characterized grain orientation maps at each stage of the process revealed the corresponding microstructure revolution which provides insights into underlying mechanistic
Screening of external magnetic perturbation fields due to sheared plasma flow
Within the single fluid resistive magnetohydrodynamic model, systematic toroidal modelling efforts are devoted to investigate the plasma response induced screening of the applied external 3D magnetic field perturbations in the presence of sheared toroidal flow. One particular issue of interest is addressed, when the local flow speed approaches zero at the perturbation rational surface inside the plasma. Subtle screening physics, associated with the favourable averaged toroidal curvature effect (the GGJ effect (Glasser et al 1975 Phys. Fluids 7 875)), is found to play an essential role during slow flow near the rational surface by enhancing the screening at reduced flow. A strong cancellation effect between different terms of Ohm's law is discovered, leading to different screening physics in the GGJ regime, as compared to that of conventional screening of the typical resistive-inertial regime occurring at faster flow. These modelling results may be applicable to interpret certain mode locking experiments, as well as type-I edge localized mode suppression experiments, with resonant magnetic field perturbations being applied to tokamak plasmas at low input toroidal torque
Collaborative Trolley Transportation System with Autonomous Nonholonomic Robots
Cooperative object transportation using multiple robots has been intensively
studied in the control and robotics literature, but most approaches are either
only applicable to omnidirectional robots or lack a complete navigation and
decision-making framework that operates in real time. This paper presents an
autonomous nonholonomic multi-robot system and an end-to-end hierarchical
autonomy framework for collaborative luggage trolley transportation. This
framework finds kinematic-feasible paths, computes online motion plans, and
provides feedback that enables the multi-robot system to handle long lines of
luggage trolleys and navigate obstacles and pedestrians while dealing with
multiple inherently complex and coupled constraints. We demonstrate the
designed collaborative trolley transportation system through practical
transportation tasks, and the experiment results reveal their effectiveness and
reliability in complex and dynamic environments
Characterization of high-resolution aerosol mass spectra of primary organic aerosol emissions from Chinese cooking and biomass burning
Aerosol mass spectrometry has proved to be a powerful tool to measure
submicron particulate composition with high time resolution. Factor analysis
of mass spectra (MS) collected worldwide by aerosol mass spectrometer (AMS)
demonstrates that submicron organic aerosol (OA) is usually composed of
several major components, such as oxygenated (OOA), hydrocarbon-like (HOA),
biomass burning (BBOA), and other primary OA. In order to help
interpretation of component MS from factor analysis of ambient OA datasets,
AMS measurements of different primary sources is required for comparison.
Such work, however, has been very scarce in the literature, especially for
high resolution MS (HR-MS) measurements, which performs improved
characterization by separating the ions of different elemental composition
at each <i>m</i>/<i>z</i> in comparison with unit mass resolution MS (UMR-MS)
measurements. In this study, primary emissions from four types of Chinese
cooking (CC) and six types of biomass burning (BB) were simulated
systematically and measured using an Aerodyne High-Resolution Time-of-Flight
AMS (HR-ToF-AMS). The MS of the CC emissions show high similarity, with <i>m</i>/<i>z</i>
41 and <i>m</i>/<i>z</i> 55 being the highest signals; the MS of the BB emissions also
show high similarity, with <i>m</i>/<i>z</i> 29 and <i>m</i>/<i>z</i> 43 being the highest signals. The
MS difference between the CC and BB emissions is much bigger than that
between different CC (or BB) types, especially for the HR-MS. The O/C ratio
of OA ranges from 0.08 to 0.13 for the CC emissions and from 0.18 to 0.26
for the BB emissions. The UMR ions of <i>m</i>/<i>z</i> 43, <i>m</i>/<i>z</i> 44, <i>m</i>/<i>z</i> 57, and <i>m</i>/<i>z</i> 60,
usually used as tracers in AMS measurements, were examined for their HR-MS
characteristics in the CC and BB emissions. In addition, the MS of the CC
and BB emissions are also compared with component MS from factor analysis of
ambient OA datasets observed in China, as well as with other AMS
measurements of primary sources in the literature. The MS signatures of
cooking and biomass burning emissions revealed in this study can be used as
important reference for factor analysis of ambient OA datasets, especially
for the relevant studies in East Asia
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