Effects of rarefaction on cavity flow in the slip regime

The Navier-Stokes-Fourier equations, with boundary conditions that account for the effects of velocity-slip and temperature-jump, are compared to the direct simulation Monte Carlo method for the case of a lid-driven micro-cavity. Results are presented for Knudsen numbers within the slip-flow regime where the onset of nonequilibrium effects are usually observed. Good agreement is found in predicting the general features of the velocity field and the recirculating flow. However, although the steady-state pressure distributions along the walls of the driven cavity are generally in good agreement with the Monte Carlo data, there is some indication that the results are starting to show noticeable differences, particularly at the separation and reattachment points. The modified Navier-Stokes-Fourier equations consistently overpredict the maximum and minimum pressure values throughout the slip regime. This highlights the need for alternative boundary formulations or modeling techniques that can provide accurate and computationally economic solutions over a wider range of Knudsen numbers

Micro-scale cavities in the slip - and transition - flow regimes

Differences between Navier-Stokes-Fourier (NSF) slip/jump solutions and direct simulation Monte-Carlo (DSMC) computations are highlighted for a micro lid-driven cavity problem. The results indicate a need for better modelling techniques which at the same time retain low computational cost of NSF models. We also highlight the fact thatmany micro-flows that have been considered are simple planar flows and typical classification systems are defined on such flows. We show that for complex flows, such as thedriven cavity, non-equilibrium effects are more appreciable and their onset occurs at lower Knudsen numbers than expected

Epidermolysis Bullosa Acquisita Antigen, a Major Cutaneous Basement Membrane Component, Is Synthesized by Human Dermal Fibroblasts and Other Cutaneous Tissues

The epidermolysis bullosa acquisita (EBA) antigen is identified as 2 chains: a 290,000-dalton protein and a less prominent 145,000-dalton protein. The 290,000-dalton chain is synthesized by human keratinocytes in culture. In this study, we show that the 290,000-dalton chain is synthesized by human skin fibroblasts and cutaneous human tumors. In contrast, HT1080 cells, a human sarcoma cell line known to produce matrix molecules (such as laminin and type IV collagen), does not synthesize the EBA antigen. Further, the EBA antigen is absent from serum and blood components, placenta, amnion, lung, and the EHS tumor, a murine sarcoma that produces large amounts of laminin, type IV collagen, nidogen, entactin, and basement membrane proteoglycan but is present in cutaneous tumors of adnexal and epithelial origin. These data suggest that while the EBA antigen is synthesized by both human skin keratinocytes and fibroblasts and is therefore not specific for a primordial germ layer, it does appear to be specific for tissue containing a stratified squamous epithelium

Neonatal Foreskin Substrate Has Limitations for the Immunofluorescent Screening of Monoclonal Antibodies

Two monoclonal antibodies to type IV collagen showed a marked decrease in the labeling of the dermal-epidermal junction of neonatal foreskin while the basement membrane around dermal blood vessels was brightly stained. In contrast, these antibodies labeled the junction and dermal blood vessels with approximately equal intensity when adult skin of nonforeskin site was used as substrate. Other antibodies to matrix molecules (bullous pemphigoid antigen, epidermolysis bullosa acquisita antigen, and laminin) showed excellent staining of both the dermal-epidermal junction and dermal blood vessels in both neonatal foreskin and adult skin. Further, the ultrastructural appearance of the substrates appeared identical. The implication is that neonatal foreskin is not a good substrate to use for the routine screening of monoclonal antibodies to matrix components by indirect immunofluorescence since a "false negative" evaluation may occur

Confronting Persistent Challenges through Research-Based Programming for Experienced School Leaders

This paper’s thesis of human agency derived from the South Carolina Successful School Principalship Project’s (SCSSPP) findings. In these schools, principals had leveraged a variety of schoolwide initiatives to enact the vision that all students would be successful despite their rurality and poverty. These findings were the underlying design for two regional cross-district pilot programs. Known as Leadership 2.0 and Leadership 3.0, the development of agency was constructed through cognitive coaching and based on principals of adult learning. Initial evaluation of participants\u27 first year reactions show consistently high perceptions of all aspects of the principals used for their professional learning

Dilution of Dipolar Interactions in a Spin-labeled, Multimeric Metalloenzyme for DEER Studies

The metallo-β-lactamases (MβLs), which require one or two Zn(II) ions in their active sites for activity, hydrolyze the amide bond in β-lactam-containing antibiotics, and render the antibiotics inactive. All known MβLs contain a mobile element near their active sites, and these mobile elements have been implicated in the catalytic mechanisms of these enzymes. However little is known about the dynamics of these elements. In this study, we prepared a site-specific, double spin-labeled analog of homotetrameric MβL L1 with spin labels at positions 163 and 286 and analyzed the sample with DEER (double electron electron resonance) spectroscopy. Four unique distances were observed in the DEER distance distribution, and these distances were assigned to the desired intramolecular dipolar coupling (between spin labels at positions 163 and 286 in one subunit) and to intermolecular dipolar couplings. To rid the spin-labeled analog of L1 of the intermolecular couplings, spin-labeled L1 was “diluted” by unfolding/refolding the spin-labeled enzyme in the presence of excess wild-type L1. DEER spectra of the resulting, spin-diluted enzyme revealed a single distance corresponding to the desire intramolecular dipolar coupling

Atrazine and Water Quality: An Evaluation of Restricting Atrazine Use on Corn and Sorghum to Postemergent Applications

Atrazine is the most widely used herbicide for corn and sorghum and the most commonly encountered in ground and surface water. In addition to water quality problems, atrazine poses hazards through atmospheric transport, food residues, and exposure of applications and wildlife. If atrazine use is restricted, substitute herbicides will come into wider use, increasing the likelihood of occurrence of their own sets of potentially undesirable side effects and imposing cost or efficacy penalties