663 research outputs found
Evaluation of remote sensing techniques on selected forest sites in Florida
There are no author-identified significant results in this report
Chiral Symmetry Breaking in QCD: A Variational Approach
We develop a "variational mass" expansion approach, recently introduced in
the Gross--Neveu model, to evaluate some of the order parameters of chiral
symmetry breakdown in QCD. The method relies on a reorganization of the usual
perturbation theory with the addition of an "arbitrary quark mass , whose
non-perturbative behaviour is inferred partly from renormalization group
properties, and from analytic continuation in properties. The resulting
ansatz can be optimized, and in the chiral limit we estimate the
dynamical contribution to the "constituent" masses of the light quarks
; the pion decay constant and the quark condensate .Comment: 10 pages, no figures, LaTe
Lewis J. Sundquist: Augustana Alum of 1886
Lewis J. Sundquist graduated from Augustana in 1886. We will discuss his career as a pastor, his family history, and his genealogy
Activity of Daptomycin or Linezolid in Combination with Rifampin or Gentamicin Against Biofilm-Forming Enterococcus faecalis or E. faecium in an In Vitro Pharmacodynamic Model Using Simulated Endocardial Vegetations and an In Vivo Survival Assay Using Galleria mellonella Larvae
Enterococci are the third most frequent cause of infective endocarditis. A high-inoculum stationary-phase in vitro pharmacodynamic model with simulated endocardial vegetations was used to simulate the human pharmacokinetics of daptomycin at 6 or 10 mg/kg of body weight/day or linezolid at 600 mg every 12 h (q12h), alone or in combination with gentamicin at 1.3 mg/kg q12h or rifampin at 300 mg q8h or 900 mg q24h. Biofilm-forming, vancomycin-susceptible Enterococcus faecalis and vancomycin-resistant Enterococcus faecium (vancomycin-resistant enterococcus [VRE]) strains were tested. At 24, 48, and 72 h, all daptomycin-containing regimens demonstrated significantly more activity (decline in CFU/g) than any linezolid-containing regimen against biofilm-forming E. faecalis. The addition of gentamicin to daptomycin (at 6 or 10 mg/kg) in the first 24 h significantly improved bactericidal activity. In contrast, the addition of rifampin delayed the bactericidal activity of daptomycin against E. faecalis, and the addition of rifampin antagonized the activities of all regimens against VRE at 24 h. Also, against VRE, the addition of gentamicin to linezolid at 72 h improved activity and was bactericidal. Rifampin significantly antagonized the activity of linezolid against VRE at 72 h. In in vivo Galleria mellonella survival assays, linezolid and daptomycin improved survival. Daptomycin at 10 mg/kg improved survival significantly over that with linezolid against E. faecalis. The addition of gentamicin improved the efficacy of daptomycin against E. faecalis and those of linezolid and daptomycin against VRE. We conclude that in enterococcal infection models, daptomycin has more activity than linezolid alone. Against biofilm-forming E. faecalis, the addition of gentamicin in the first 24 h causes the most rapid decline in CFU/g. Of interest, the addition of rifampin decreased the activity of daptomycin against both E. faecalis and VRE
Variational solution of the Gross-Neveu model; 2, finite-N and renormalization
We show how to perform systematically improvable variational calculations in the O(2N) Gross-Neveu model for generic N, in such a way that all infinities usually plaguing such calculations are accounted for in a way compatible with the renormalization group. The final point is a general framework for the calculation of non-perturbative quantities like condensates, masses, etc..., in an asymptotically free field theory. For the Gross-Neveu model, the numerical results obtained from a "two-loop" variational calculation are in very good agreement with exact quantities down to low values of N
Optimized Perturbation Theory for Wave Functions of Quantum Systems
The notion of the optimized perturbation, which has been successfully applied
to energy eigenvalues, is generalized to treat wave functions of quantum
systems. The key ingredient is to construct an envelope of a set of
perturbative wave functions. This leads to a condition similar to that obtained
from the principle of minimal sensitivity. Applications of the method to
quantum anharmonic oscillator and the double well potential show that uniformly
valid wave functions with correct asymptotic behavior are obtained in the
first-order optimized perturbation even for strong couplings.Comment: 11 pages, RevTeX, three ps figure
Cephalothin Analogs Inhibit GD3 Synthase and Target GD2+ Breast Cancer Stem-Like Cells in Triple Negative Breast Cancer
https://openworks.mdanderson.org/sumexp21/1117/thumbnail.jp
Increased unsaturation of lipids in cytoplasmic lipid droplets in DAOY cancer cells in response to cisplatin treatment.
Increases in 1H nuclear magnetic resonance spectroscopy (NMR) visible lipids are a well-documented sign of treatment response in cancers. Lipids in cytoplasmic lipid droplets (LDs) are the main contributors to the NMR lipid signals. Two human primitive neuroectodermal tumour cell lines with different sensitivities to cisplatin treatment were studied. Increases in NMR visible saturated and unsaturated lipids in cisplatin treated DAOY cells were associated with the accumulation of LDs prior to DNA fragmentation due to apoptosis. An increase in unsaturated fatty acids (UFAs) was detected in isolated LDs from DAOY cells, in contrast to a slight decrease in UFAs in lipid extracts from whole cells. Oleic acid and linoleic acid were identified as the accumulating UFAs in LDs by heteronuclear single quantum coherence spectroscopy (HSQC). 1H NMR lipids in non-responding PFSK-1 cells were unchanged by exposure to 10 μM cisplatin. These findings support the potential of NMR detectable UFAs to serve as a non-invasive marker of tumour cell response to treatment
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