3,425 research outputs found
Influence of fluorescent antibody probe specificity on flow cytometric analysis of antibody-producing cells
No full textIn the flow cytometric analysis of the stability of antibody-producing cells, fluorescent antibody probes specific for immunoglobulin heavy chains have been widely utilized to quantify intracellular antibodies. To investigate the effect of the specificity of antibody probes on flow cytometric analysis, non-producing subclones of the 6-31 transfectoma were stained with fluorescein isothiocyanate (FITC)-conjugated anti-human IgGs specific for heavy chain and light chain, respectively. The use of heavy chain-specific probe identified heavy chain-only producers as producers, whereas the use of light chain-specific probe identified light chain-only producers as producers. Thus, both heavy chain-specific and light chain-specific antibody probes should be used for the accurate evaluation of a heterogeneous non-producing population. Furthermore, the results of the flow cytometric analysis were confirmed by immunoblotting, suggesting that flow cytometry is a useful technique for the rapid evaluation of the stability of transfectomas producing chimeric antibody
Intracellular responses of antibody-producing H69K-NGD transfectoma subjected to hyperosmotic pressure
No full textWhen subjected to hyperosmotic pressure by NaCl addition, H69K-NGD transfectoma, like KR12H-2 transfectoma, displayed decreased specific growth rate (p) and increased specific antibody productivity (q(Ab)): Elevation of medium osmolality from 280 mOsm/kg to 415 mOsm/kg decreased P by 79% in batch cultures of H69K-NGD transfectoma, while it increased q(Ab) 103%. However, unlike KR12H-2 tranfectoma, enhanced q(Ab) of H69K-NGD transfectoma at hyperosmolalities was not due to elevated levels of Ig mRNAs. In hyperosmotic cultures of H69K-NGD transfectoma, heavy-chain mRNA per cell was not enhanced with increasing osmolality. Hyperosmotic pressure was found to preferentially enhance immunoglobulin (Ig) translation rates of H69K-NGD transfectoma. However, under hyperosmotic pressure, the translation rate of Ig polypeptides was not enhanced as much as q(Ab). This result suggests that hyperosmotic pressure also influences the post-translational process. Taken together, the results obtained show that intracellular response of transfectomas to hyperosmotic pressure, in regard to the main intracellular steps of the antibody secretory pathway, is cell-fine dependent
Stability of Transfectomas Producing Chimeric Antibody against Pre-S2 Surface Antigen of HBV during a Long-term Culture
No full text
Influence of the Specificity of FITC-conjugated Antibody Probe on Flow Cytometric Analysis of the Stability of Antibody Producing Cells
No full textOxygen reduction mechanism at Sm0.5Sr0.5CoO 3-δ/Sm0.2Ce0.8O1.9 composite cathode for solid oxide fuel cell
No full textDirect numerical simulation of stagnation region flow and heat transfer with free-stream turbulence
No full textA direct numerical simulation is performed for stagnation- region flow with free- stream turbulence. A fully implicit second- order time- advancement scheme with fourth- order finite differences and an optimized scheme are employed. The optimized scheme is developed to save computational cost. The free- stream turbulence is a precomputed field of isotropic turbulence. The present DNS results in the " damping'' and " attached amplifying'' regimes are found to be similar to those of the organized inflow disturbances. Emphasis is placed on the flow and temperature fields in the " detached amplifying'' regime. The contours of instantaneous flow field illustrate that streamwise vortices are stretched in the streamwise direction by mean strain rate. The temperature field is also stretched in the streamwise direction near the wall. The surface contours reveal that the temperature field is influenced significantly by streamwise vorticity. Due to the dominance of the mean strain, the log- law region is not observed for (u) over bar and (T) over tilde, the inner scaling fails, but the outer scaling works. The single- point turbulence statistics and the turbulent statistics budgets are obtained. The flow statistics reflect the typical characteristics of stagnation- region flow which are generically different from those of other canonical shear flows. One of the typical features of the budgets is that the velocity pressure correlation and the turbulent transport play significant roles in the stagnation- region flow. Finally, the present simulation data are compared with experimental results. It is found that the effect of large- scale eddies on the enhancement of wall heat transfer is substantial in the turbulent stagnation- region heat transfer. (C) 2003 American Institute of Physics
Frictional modes of barrel shaped piston rings under flooded lubrication
No full textA friction force measurement system using the floating liner method was developed to study the frictional behavior of piston rings. The measurement system was designed to control the effect of the secondary piston motion and to control temperatures of the cylinder wall and oil. The friction force between the barrel shaped piston ring and the cylinder liner was measured under flooded oil supply conditions. The measured friction forces were classified into five frictional modes with regard to the combination of predominant lubrication regimes (boundary, mixed and hydrodynamic lubrication) and stroke regions (mid-stroke and dead centers). The modes were identified on a Stribeck diagram, where the friction coefficients were evaluated both at mid-stroke and at the dead centers. (C) 2000 Published by Elsevier Science Ltd
Measurement devices for piston assembly friction and oil film thickness
No full textA technique for estimating the instantaneous frictional force between the piston assembly and the cylinder wall has been developed by improving the moveable bore technique. The technique can be easily applied to small multi-cylinder engines since its structure is simple and stable so that the measuring range could be extended. The reliability of the friction data can be improved by a newly proposed compensation method. The technique was applied to a four cylinder SI engine under various engine speeds. engine loads. and oil viscosity. An instrument for measuring the oil film thickness on the piston rings was also developed by using the commercially available gap sensors. It as possible to measure the oil film thickness,, on thin oil ring rails as well as on the compression rings. The frictional characteristics were established as a relationship between frictional mean effective pressure and a parameter which is the product of the piston mean speed and the oil viscosity.Korean Ministry of Industry and Energy under the scheme of the Enterprise of the Next Generation Vehicle Technolog
Estimation of operational strains from vibration measurements: An application to lead wires of chips on printed circuit board
No full textDynamic strain in structures is normally measured using strain gauges. When direct strain measurement is not possible, vibration measurement can be an indirect practical alternative. That is, vibrations are measured, typically using acceleration pick-ups, on the underlying system under operational conditions and a certain relationship between strains and accelerations is imposed on the measured accelerations to estimate the strains. Therefore, this relationship or transformation matrix between the strain and vibration is very critical for the indirect estimation to be successful. The transformation matrix is often inevitably derived not under the real operational conditions, but under the idealized laboratory conditions or using computer simulations. This means that boundary conditions under which this transformation matrix is obtained are extremely important. In this study, this problem is discussed in detail and an application to the estimation of strains in lead wires connecting chips to a printed circuit board subject to loading by a cooling fan is illustrated. (C) 1998 Academic Press Limited
- …
