5,741 research outputs found
On the theory of polarization transfer in inhomogeneous magnetized plasmas
Polarization transfer theory in inhomogeneous magnetized plasmas with mode couplin
Buckling of Low Arches or Curved Beams of Small Curvature
A general solution, based on the classical buckling criterion, is given for the problem of buckling of low arches under a lateral loading acting toward the center of curvature. For a sinusoidal arch under sinusoidal loading, the critical load can be expressed exactly as a simple function of the beam dimension parameters. For other arch shapes and load distributions, approximate values of the critical load can be obtained by summing a few terms of a rapidly converging Fourier series. The effects of initial end thrust and axial and lateral elastic support are discussed. The buckling load based on energy criterion of Karman and Tsien is also calculated. Results for both the classical and the energy criteria are compared with experimental results
Cyclin F Is Degraded during G2-M by Mechanisms Fundamentally Different from Other Cyclins
Cyclin F, a cyclin that can form SCF complexes and bind to cyclin B, oscillates in the cell cycle with a pattern similar to cyclin A and cyclin B. Ectopic expression of cyclin F arrests the cell cycle in G2/M. How the level of cyclin F is regulated during the cell cycle is completely obscure. Here we show that, similar to cyclin A, cyclin F is degraded when the spindle assembly checkpoint is activated and accumulates when the DNA damage checkpoint is activated. Cyclin F is a very unstable protein throughout much of the cell cycle. Unlike other cyclins, degradation of cyclin F is independent of ubiquitination and proteasome-mediated pathways. Interestingly, proteolysis of cyclin F is likely to involve metalloproteases. Rapid destruction of cyclin F does not require the N-terminal F-box motif but requires the COOH-terminal PEST sequences. The PEST region alone is sufficient to interfere with the degradation of cyclin F and confer instability when fused to cyclin A. These data show that although cyclin F is degraded at similar time as the mitotic cyclins, the underlying mechanisms are entirely distinct
A KINETIC ANALYSIS TO POWERISER (AN ENERGY STORAGE AND RETURN SPRING LEAF DEVICE)
The purpose of this study was to explore the efficiency of an Energy Storage and Return (ESAR) spring leaf walking device (Poweriser) during the walking. The result showed that the walking efficiency of poweriser was around 80% contrast to a normal walk during the mid-stance phase. In the meanwhile, the muscle activation mainly occurred in thigh muscle probably resulted from the ankle lock design of poweriser. On the other hand, the study also found that all the participants demonstrated a similar VGRF pattern and relative lower muscle loading on shank muscle during the continuous vertical jump with the poweriser. The present investigators doubted that the efficiency and performance of poweriser was influenced by the stiffness of leaf spring, the type of motion, and participant’s body mass
Dynamical regimes and hydrodynamic lift of viscous vesicles under shear
The dynamics of two-dimensional viscous vesicles in shear flow, with
different fluid viscosities and inside and
outside, respectively, is studied using mesoscale simulation techniques.
Besides the well-known tank-treading and tumbling motions, an oscillatory
swinging motion is observed in the simulations for large shear rate. The
existence of this swinging motion requires the excitation of higher-order
undulation modes (beyond elliptical deformations) in two dimensions.
Keller-Skalak theory is extended to deformable two-dimensional vesicles, such
that a dynamical phase diagram can be predicted for the reduced shear rate and
the viscosity contrast . The simulation results
are found to be in good agreement with the theoretical predictions, when
thermal fluctuations are incorporated in the theory. Moreover, the hydrodynamic
lift force, acting on vesicles under shear close to a wall, is determined from
simulations for various viscosity contrasts. For comparison, the lift force is
calculated numerically in the absence of thermal fluctuations using the
boundary-integral method for equal inside and outside viscosities. Both methods
show that the dependence of the lift force on the distance of
the vesicle center of mass from the wall is well described by an effective
power law for intermediate distances with vesicle radius .
The boundary-integral calculation indicates that the lift force decays
asymptotically as far from the wall.Comment: 13 pages, 13 figure
Measurement of teicoplanin by liquid chromatography-tandem mass spectrometry:development of a novel method
Teicoplanin is an antibiotic used for the treatment of endocarditis, osteomyelitis, septic arthritis and methicillin-resistant Staphylococcus aureus. Teicoplanin is emerging as a suitable alternative antibiotic to vancomycin, where their trough serum levels are monitored by immunoassay routinely. This is the first report detailing the development of a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for measuring teicoplanin in patients' serum
Dynamic Modes of Microcapsules in Steady Shear Flow: Effects of Bending and Shear Elasticities
The dynamics of microcapsules in steady shear flow was studied using a
theoretical approach based on three variables: The Taylor deformation parameter
, the inclination angle , and the phase angle of
the membrane rotation. It is found that the dynamic phase diagram shows a
remarkable change with an increase in the ratio of the membrane shear and
bending elasticities. A fluid vesicle (no shear elasticity) exhibits three
dynamic modes: (i) Tank-treading (TT) at low viscosity of
internal fluid ( and relaxes to constant values), (ii)
Tumbling (TB) at high ( rotates), and (iii) Swinging
(SW) at middle and high shear rate (
oscillates). All of three modes are accompanied by a membrane ()
rotation. For microcapsules with low shear elasticity, the TB phase with no
rotation and the coexistence phase of SW and TB motions are induced by
the energy barrier of rotation. Synchronization of rotation with
TB rotation or SW oscillation occurs with integer ratios of rotational
frequencies. At high shear elasticity, where a saddle point in the energy
potential disappears, intermediate phases vanish, and either or
rotation occurs. This phase behavior agrees with recent simulation results of
microcapsules with low bending elasticity.Comment: 11 pages, 14 figure
Exploring service climate and employee performance in multicultural service settings
Purpose: The purpose of this paper is to introduce a new conceptual model that incorporates internal service quality as a mediator between service climate and employee performance and two personal cultural orientations (independence and interdependence) as the moderators of these relationships. Design/methodology/approach: An online survey of 353 employees representing 19 different nationalities, working in 18 branches and offices of a multinational business-to-business (B2B) civil engineering services firm, spread across 14 countries. Findings: All the hypotheses are supported. Specifically, internal service quality mediates the influence of service climate on employee performance and these relationships are stronger for employees with interdependent (vs independent) cultural orientations. Research limitations/implications: This paper uses data collected from the employees in a single B2B firm in one industry (Civil Engineering Services) and focuses on a few key variables, which may restrict the generalizability of its findings. Practical implications: The findings of this paper highlight the importance of cultural factors in building a service climate in multinational service organizations to help their employees work more effectively and efficiently with their colleagues from diverse cultural backgrounds. Originality/value: This paper clarifies the relationships among service climate, internal service quality and employee performance, by showing that internal service quality mediates the influence of service climate on employee performance
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