511 research outputs found
Direct Fragmentation of Quarkonia Including Fermi Motion Using Light-cone Wave Function
We investigate the effect of Fermi motion on the direct fragmentation of the
and states employing a light-cone wave function. Consistent
with such a wave function we set up the kinematics of a heavy quark fragmenting
into a quarkonia such that the Fermi motion of the constituents split into
longitudinal as well as transverse direction and thus calculate the
fragmentation functions for these states. In the framework of our
investigation, we estimate that the fragmentation probabilities of and
may increase at least up to 14 percent when including this degree of
freedom.Comment: 7 pages 5 figures Appeared in EPJC; Fig 1 and Appendix revise
CopyRNeRF: Protecting the CopyRight of Neural Radiance Fields
Neural Radiance Fields (NeRF) have the potential to be a major representation
of media. Since training a NeRF has never been an easy task, the protection of
its model copyright should be a priority. In this paper, by analyzing the pros
and cons of possible copyright protection solutions, we propose to protect the
copyright of NeRF models by replacing the original color representation in NeRF
with a watermarked color representation. Then, a distortion-resistant rendering
scheme is designed to guarantee robust message extraction in 2D renderings of
NeRF. Our proposed method can directly protect the copyright of NeRF models
while maintaining high rendering quality and bit accuracy when compared among
optional solutions.Comment: 11 pages, 6 figures, accepted by iccv 2023 non-camera-ready versio
Polymer translocation through a nanopore under an applied external field
We investigate the dynamics of polymer translocation through a nanopore under
an externally applied field using the 2D fluctuating bond model with
single-segment Monte Carlo moves. We concentrate on the influence of the field
strength , length of the chain , and length of the pore on forced
translocation. As our main result, we find a crossover scaling for the
translocation time with the chain length from for
relatively short polymers to for longer chains, where
is the Flory exponent. We demonstrate that this crossover is due to the
change in the dependence of the translocation velocity v on the chain length.
For relatively short chains , which crosses over to for long polymers. The reason for this is that with increasing
there is a high density of segments near the exit of the pore, which slows down
the translocation process due to slow relaxation of the chain. For the case of
a long nanopore for which , the radius of gyration along
the pore, is smaller than the pore length, we find no clear scaling of the
translocation time with the chain length. For large , however, the
asymptotic scaling is recovered. In this regime, is almost independent of . We have previously found that for a polymer,
which is initially placed in the middle of the pore, there is a minimum in the
escape time for . We show here that this minimum
persists for a weak fields such that is less than some critical value,
but vanishes for large values of .Comment: 25 Pages, 10 figures. Submitted to J. Chem. Phys. J. Chem. Phys. 124,
in press (2006
Hamiltonian Formalism of the de-Sitter Invariant Special Relativity
Lagrangian of the Einstein's special relativity with universal parameter
() is invariant under Poincar\'e transformation which preserves
Lorentz metric . The has been extended to be
one which is invariant under de Sitter transformation that preserves so called
Beltrami metric . There are two universal parameters and in
this Special Relativity (denote it as ). The
Lagrangian-Hamiltonian formulism of is formulated in this
paper. The canonic energy, canonic momenta, and 10 Noether charges
corresponding to the space-time's de Sitter symmetry are derived. The canonical
quantization of the mechanics for -free particle is
performed. The physics related to it is discussed.Comment: 24 pages, no figur
Gait analysis for designing a new assistive knee brace
Assistive knee brace is a species of wearable lower extremity exoskeletons. In this research, an assistive knee brace was developed by integrating a multifunctional actuator with a custom-made knee-ankle-foot orthosis. In the study, the location of the actuator is moved up to the lateral side of the hip, instead of knee joint. Waist belt and shoulder belt are appended on the knee brace. This paper aimed to improve the design of the assistive knee braces through gait analysis. By walking with the knee braces, the spatial and temporal gait parameters, joint kinematics and joint kinetics parameters were evaluated, and the changes from normal walking were compared as well. The experimental results showed that walking with the developed knee brace provided minimal hindrance to the wearer. © 2011 IEEE
Experimental studies on kinematics and kinetics of walking with an assistive knee brace
Assistive knee brace is a species of wearable lower extremity exoskeletons. Such assistive equipment can enhance people's strength and provide desired locomotion to have advantages over wheelchairs, which are commonly used for patients with mobility disorders. However, the integration between the assistive knee brace and the user is challenging as inaccurate alignments may adversely affect the biomechanics of the knee joint. The goal of this study is to evaluate the changes between normal walking and walking with an assistive knee brace in "off" mode. The assistive knee brace was developed by integrating a multifunctional actuator with a custom-made knee-ankle-foot orthosis in order to minimize excessive shifting and to improve alignment to the knee joint. Spatial and temporal gait parameters, joint kinematics and joint kinetics parameters were compared. In general, the observed results showed that most of the gait parameters were not affected when walking with the knee brace. The only significant differences were found in knee flexion and knee rotational motions. These results indicated that walking with the developed knee brace provided minimal hindrance to the user and assured that assistive torque can be applied to the knee joint
Microparticle-mediated transfer of the viral receptors CAR and CD46, and the CFTR channel in a CHO cell model confers new functions to target cells
Cell microparticles (MPs) released in the extracellular milieu can embark plasma membrane and intracellular components which are specific of their cellular origin, and transfer them to target cells. The MP-mediated, cell-to-cell transfer of three human membrane glycoproteins of different degrees of complexity was investigated in the present study, using a CHO cell model system. We first tested the delivery of CAR and CD46, two monospanins which act as adenovirus receptors, to target CHO cells. CHO cells lack CAR and CD46, high affinity receptors for human adenovirus serotype 5 (HAdV5), and serotype 35 (HAdV35), respectively. We found that MPs derived from CHO cells (MP-donor cells) constitutively expressing CAR (MP-CAR) or CD46 (MP-CD46) were able to transfer CAR and CD46 to target CHO cells, and conferred selective permissiveness to HAdV5 and HAdV35. In addition, target CHO cells incubated with MP-CD46 acquired the CD46-associated function in complement regulation. We also explored the MP-mediated delivery of a dodecaspanin membrane glycoprotein, the CFTR to target CHO cells. CFTR functions as a chloride channel in human cells and is implicated in the genetic disease cystic fibrosis. Target CHO cells incubated with MPs produced by CHO cells constitutively expressing GFP-tagged CFTR (MP-GFP-CFTR) were found to gain a new cellular function, the chloride channel activity associated to CFTR. Time-course analysis of the appearance of GFP-CFTR in target cells suggested that MPs could achieve the delivery of CFTR to target cells via two mechanisms: the transfer of mature, membrane-inserted CFTR glycoprotein, and the transfer of CFTR-encoding mRNA. These results confirmed that cell-derived MPs represent a new class of promising therapeutic vehicles for the delivery of bioactive macromolecules, proteins or mRNAs, the latter exerting the desired therapeutic effect in target cells via de novo synthesis of their encoded proteins
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