802 research outputs found
Magnetization Losses in Multifilament Coated Superconductors
We report the results of a study of the magnetization losses in experimental
multifilament, as well as control (uniform), coated superconductors exposed to
time-varying magnetic field of various frequencies. Both the hysteresis loss,
proportional to the sweep rate of the applied magnetic field, and the coupling
loss, proportional to the square of the sweep rate, have been observed. A
scaling is found that allows us to quantify each of these contributions and
extrapolate the results of the experiment beyond the envelope of accessible
field amplitude and frequency. The combined loss in the multifilament conductor
is reduced by about 90% in comparison with the uniform conductor at full field
penetration at sweep rate as high as 3T/s
Bone morphological effects on post-implantation remodeling of maxillary anterior buccal bone: A clinical and biomechanical study
This is the final version of the article. Available from Elsevier via the DOI in this record.Purpose
This study combines clinical investigation with finite element (FE) analysis to explore the effects of buccal bone thickness (BBT) on the morphological changes of buccal bone induced by the loaded implant.
Methods
One specific patient who had undergone an implant treatment in the anterior maxilla and experienced the buccal bone resorption on the implant was studied. Morphological changes of the bone were measured through a series of cone-beam computed tomography (CT) scans. A three-dimensional heterogeneous nonlinear FE model was constructed based on the CT images of this patient, and the in-vivo BBT changes are correlated to the FE in-silico mechanobiological stimuli; namely, von Mises equivalent stress, equivalent strain, and strain energy density. The anterior incisory bone region of this model was then varied systematically to simulate five different BBTs (0.5, 1.0, 1.5, 2.0, and 2.5 mm), and the optimal BBT was inversely determined to minimize the risk of resorption.
Results
Significant changes in BBTs were observed clinically after 6 month loading on the implant. The pattern of bone resorption fell into a strong correlation with the distribution of mechanobiological stimuli onsite. The initial BBT appeared to play a critical role in distributing mechanobiological stimuli, thereby determining subsequent variation in BBT. A minimum initial thickness of 1.5 mm might be suggested to reduce bone resorption.
Conclusions
This study revealed that the initial BBT can significantly affect mechanobiological responses, which consequentially determines the bone remodeling process. A sufficient initial BBT is considered essential to assure a long-term stability of implant treatment.This study was supported by Australian Research Council (ARC) through Discovery and Future Fellowship Schemes (DP1095140 and FT120100947), and for Scientific Research (C) (15K11147) from the Ministry of Education, Culture, Sports, Science and Technology of Japan
Secondary-Structure Design of Proteins by a Backbone Torsion Energy
We propose a new backbone-torsion-energy term in the force field for protein
systems. This torsion-energy term is represented by a double Fourier series in
two variables, the backbone dihedral angles phi and psi. It gives a natural
representation of the torsion energy in the Ramachandran space in the sense
that any two-dimensional energy surface periodic in both phi and psi can be
expanded by the double Fourier series. We can then easily control
secondary-structure-forming tendencies by modifying the torsion-energy surface.
For instance, we can increase/decrease the alpha-helix-forming-tendencies by
lowering/raising the torsion-energy surface in the alpha-helix region and
likewise increase/decrease the beta-sheet-forming tendencies by
lowering/raising the surface in the beta-sheet region in the Ramachandran
space. We applied our approach to AMBER parm94 and AMBER parm96 force fields
and demonstrated that our modifications of the torsion-energy terms resulted in
the expected changes of secondary-structure-forming-tendencies by performing
folding simulations of alpha-helical and beta-hairpin peptides.Comment: 13 pages, (Revtex4), 5 figure
The Effect of Aerobic and Anaerobic Physical Training on the Absorptive Cells, Absorption of Carbohydrate and Protein in Small Intestine
The purpose of this study is to investigate the morphofunctional response of a total number of absorptive cells, and carbohydrate and protein absorption capability in the small intestine of Rattus norvegicus strain Wistar (RNSW) that has been subjected to aerobic and anaerobic physical training based on the morphofunctional physiological paradigm. This study was based on the separate sample pretest-posttest control group design, using a t-test, and multivariate SPSS ten program, with five percent level of significance. The sample consisted of one hundred and twenty, male RNSW, with average age of five months, and body weight of 246-278 grams. They were divided into twelve groups at random, i.e. four pretest groups, two control groups, and six treated groups where different diets were given thirty minutes before undergoing posttest. The experimental animals underwent four weeks physical training (twelve times), three groups were given aerobic physical training by swimming with a burden of three percent fasting body weight, the others three groups received anaerobic physical training by swimming with a burden of nine percent fasting body weight. The experiment was conducted at night, between 7.30 PM to 10.30 PM, in a water with a temperature of 28°C to 30°C. Result of the study revealed: (1) Aerobic and anaerobic physical training, increased the number of absorptive cells (t = -73,281, p = 0,000), and increased the absorptive capacity of carbohydrate and protein (Hotelling's Trace = 0,244, p = 0,000). (2) There was a difference in the increased absorptive capacity of carbohydrate and protein among groups (Hotelling's Trace = 0,404a, p = 0,000). Aerobic physical training had less influence than anaerobic physical training on the increased number of absorptive cells, and the absorptive capacity of carbohydrate and protein in the small intestine. In conclusion: (1) Aerobic physical training of swimming with a burden of three percent fasting body weight, and anaerobic physical training of swimming with a burden nine percent fasting body weight correlate with the increase the number of absorptive cells, and carbohydrate and protein absorptive capacity of the small intestine. (2) Anaerobic physical training of swimming with a burden nine percent fasting body weight has better correlation than aerobic physical training of swimming with a burden of three percent fasting body weight with the increased number of absorptive cells, and the absorptive capacity of carbohydrate and protein in the small intestine
The Effect of Aerobic and Anaerobic Physical Training on the Absorptive Cells, Absorption of Carbohydrate and Protein in Small Intestine
The purpose of this study is to investigate the morphofunctional response of a total number of absorptive cells, and carbohydrate and protein absorption capability in the small intestine of Rattus norvegicus strain Wistar (RNSW) that has been subjected to aerobic and anaerobic physical training based on the morphofunctional physiological paradigm. This study was based on the separate sample pretest-posttest control group design, using a t-test, and multivariate SPSS ten program, with five percent level of significance. The sample consisted of one hundred and twenty, male RNSW, with average age of five months, and body weight of 246-278 grams. They were divided into twelve groups at random, i.e. four pretest groups, two control groups, and six treated groups where different diets were given thirty minutes before undergoing posttest. The experimental animals underwent four weeks physical training (twelve times), three groups were given aerobic physical training by swimming with a burden of three percent fasting body weight, the others three groups received anaerobic physical training by swimming with a burden of nine percent fasting body weight. The experiment was conducted at night, between 7.30 PM to 10.30 PM, in a water with a temperature of 28°C to 30°C. Result of the study revealed: (1) Aerobic and anaerobic physical training, increased the number of absorptive cells (t = -73,281, p = 0,000), and increased the absorptive capacity of carbohydrate and protein (Hotelling\u27s Trace = 0,244, p = 0,000). (2) There was a difference in the increased absorptive capacity of carbohydrate and protein among groups (Hotelling\u27s Trace = 0,404a, p = 0,000). Aerobic physical training had less influence than anaerobic physical training on the increased number of absorptive cells, and the absorptive capacity of carbohydrate and protein in the small intestine. In conclusion: (1) Aerobic physical training of swimming with a burden of three percent fasting body weight, and anaerobic physical training of swimming with a burden nine percent fasting body weight correlate with the increase the number of absorptive cells, and carbohydrate and protein absorptive capacity of the small intestine. (2) Anaerobic physical training of swimming with a burden nine percent fasting body weight has better correlation than aerobic physical training of swimming with a burden of three percent fasting body weight with the increased number of absorptive cells, and the absorptive capacity of carbohydrate and protein in the small intestine
Self-Consistent Second Order Perturbation Theory for the Hubbard Model in Two Dimensions
We apply self-consistent second order perturbation theory (SCSOPT) with
respect to the on-site repulsive interaction U to study the Hubbard model in
two dimensions. We investigate single particle properties of the model over the
entire doping range at zero temperature. It is shown that as doping decreases
toward half-filling -mass enhancement factor increases, while k-mass
enhancement factor decreases. The increase in -mass enhancement factor
is larger than the decrease in k-mass enhancement factor, so that total-mass is
larger than that in the non-interacting case. When particle number density per
unit cell n is given by 0.64<n<1.0 interaction enhances anisotropy of the Fermi
surface, whereas at lower densities n<0.64 interaction suppresses anisotropy of
it. Due to the decrease in k-mass enhancement factor the density of states
(DOS) at the Fermi level is suppressed. It is possible to understand the
results within the framework of the weak coupling Fermi liquid theory.Comment: 8 pages, 12 embedded EPS figures, to appear in J. Phys. Soc. Jpn.
Vol. 68-3 (1999
Biomechanical analysis of bone remodeling following mandibular reconstruction using fibula free flap
This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.Whilst the newly established biomechanical conditions following mandibular reconstruction using fibula free flap can be a critical determinant for achieving favorable bone union, little has been known about their association in a time-dependent fashion. This study evaluated the bone healing/remodeling activity in reconstructed mandible and its influence on jaw biomechanics using CT data, and further quantified their correlation with mechanobiological responses through an in-silico approach. A 66-year-old male pa- tient received mandibular reconstruction was studied. Post-operative CT scans were taken at 0, 4, 16 and 28 months. Longitudinal change of bone morphologies and mineral densities were measured at three bone union interfaces (two between the fibula and mandibular bones and one between the osteotomized fibulas) to investigate bone healing/remodeling events. Three-dimensional finite element models were created to quantify mechanobiological responses in the bone at these different time points. Bone mineral density increased rapidly along the bone interfaces over the first four months. Cortical bridging formed at the osteotomized interface earlier than the other two interfaces with larger shape discrepancy between fibula and mandibular bones. Bone morphology significantly affected mechanobiological responses in the osteotomized region ( R 2 > 0.77). The anatomic position and shape discrepancy at bone union affected the bone healing/remodeling process.This work was supported by the Australian Research Council (ARC) through the Discovery and Fellowship schemes ( DP160104602 and FT120100947 )
Development of Time- and Energy-Resolved Synchrotron-Radiation-Based Mössbauer Spectroscopy
14th International Conference on Synchrotron Radiation Instrumentation (SRI 2021) 28.03.2022 - 01.04.2022 OnlineSynchrotron-radiation based Mössbauer spectroscopy has become a useful technique capable for investigating various Mössbauer isotopes. For a typical experimental setup, the information associated with the pulse height (that is, energy) in an avalanche photodiode (APD) detector has not been used effectively. By using a system for simultaneous measurement system of time and energy associated with the APD signal, a system for the time- and energy-resolved Mössbauer spectroscopy has been developed. In this system, the pulse height information was converted to the time information through an amplitude-to-time converter applied to one of the divided signals from the APD. The corresponding time information was processed separately from another one of the divided signals. Both signals are recorded by a multi-channel scaler in an event-by-event data acquisition process. The velocity information from the Mössbauer transducer was also recorded as a tag for each signal event. Thus, the Mössbauer spectra with any time- and energy-window can be reconstructed after the data collection process. This system can be used for many purposes in time- and energy-resolved Mössbauer spectroscopy, and shows significant promise for use with other fast detectors and for various types of experiments
Magnetization Losses in Multiply Connected YBa2Cu3O6+x Coated Conductors
We report the results of a magnetization losses study in experimental
multifilament, multiply connected coated superconductors exposed to
time-varying magnetic field. In these samples, the superconducting layer is
divided into parallel stripes segregated by non-superconducting grooves. In
order to facilitate the current sharing between the stripes and thus increase
the reliability of the striated conductors, a sparse network of superconducting
bridges is superimposed on the striated film. We find that the presence of the
bridges does not substantially increase the magnetization losses, both
hysteresis and coupling, as long as the number of bridges per length of the
sample is not large. These results indicate that it is possible to find a
reasonable compromise between the competing requirements of connectivity and
loss reduction in an ac-tolerant version of the high temperature coated
conductors specifically designed for ac power applications.Comment: 19 pages, 12 figures to be published in J. Appl. Phy
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