Cofinement, entropy, and single-particle dynamics of equilibrium hard-sphere mixtures

We use discontinuous molecular dynamics and grand-canonical transition-matrix Monte Carlo simulations to explore how confinement between parallel hard walls modifies the relationships between packing fraction, self-diffusivity, partial molar excess entropy, and total excess entropy for binary hard-sphere mixtures. To accomplish this, we introduce an efficient algorithm to calculate partial molar excess entropies from the transition-matrix Monte Carlo simulation data. We find that the species-dependent self-diffusivities of confined fluids are very similar to those of the bulk mixture if compared at the same, appropriately defined, packing fraction up to intermediate values, but then deviate negatively from the bulk behavior at higher packing fractions. On the other hand, the relationships between self-diffusivity and partial molar excess entropy (or total excess entropy) observed in the bulk fluid are preserved under confinement even at relatively high packing fractions and for different mixture compositions. This suggests that the partial molar excess entropy, calculable from classical density functional theories of inhomogeneous fluids, can be used to predict some of the nontrivial dynamical behaviors of fluid mixtures in confined environments.Comment: submitted to JC

Structure Of 18'-Epivinblastine

Methyl {3aR-[3a-alpha,4-beta,5-beta,5a-beta,9(3R*,-5S*,7R*,9R*),10bR,13a-alpha]}-4-(acetyloxy)-3a-ethyl-9-[5-ethyl-1,4,5,6,7,8,9,10-octahydro-5-hydroxy-9-(methoxycarbonyl)-2H-3,7-methanoazacycloundecino[5,4-b]indol-9-yl]-3a,4,5,5a,6,11,12,13a-octahydro-5-hydroxy-8-methoxy-6-methyl-lH-indolizino-[8,1-c,d]carbazole-5-carboxy?? late methanol solvate, C46H58N4O9.2CH3OH (1), M(r) = 875.07, monoclinic, P2(1), a = 10.2759 (12), b = 22.353 (3), c = 10.4051 (12) angstrom, beta = 106.502 (9)-degrees, V = 2291.6 (5) angstrom 3, Z = 2, D(x) = 1.27 g cm-3, Mo K-alpha radiation, lambda = 0.7107 angstrom, mu = 0.8397 cm-1, F(000) = 940, T = 198 K, R = 0.0470 for 2751 reflections, F(o) greater-than-or-equal-to 4-sigma-(F(o)). The C ring of the vindoline moiety is in the boat conformation with the hydroxy group and the tertiary N in the bowsprit positions resulting in a fairly short intramolecular hydrogen-bonding interaction. The relevant parameters for O3-H3...N9 are O...N 2.651 (6), H...N 1.94 (5) angstrom and O-H...N 147 (5)-degrees. The D and E rings are in the sofa and envelope conformations, respectively. The piperidine ring of the catharanthine portion of the molecule assumes the chair conformation while the conformation of the azacyclononene ring is a boat-chair. An intramolecular hydrogen bond between the indolino NH of the catharanthine moiety and methoxy O (O25) of the vindoline moiety is also observed. The relevant parameters for N16'-H16'...O25 are N...O 2.827 (6), H...N2.14 (6) angstrom and O-H...N 136 (5)-degrees.National Institutes of Health (GM 29801)ChemistryBiochemistr

The Structure At 198 K Of (1R,5R,15R,16R)-5-Isopropenyl-2-Methyl-1(N-(Trans-2-Phenylcyclohexyloxyc Arbonyl)Amino)-2-Cyclohexene

trans-2-Phenylcyclohexyl N-(5-isopropenyl-2-methyl-2-cyclohexan-1-yl)carbamate, C23H31NO2, M(r) = 353.50, orthorhombic, P2(1)2(1)2(1), a = 8.813 (2), b = 9.043 (2), c = 25.643 (5) angstrom, V = 2043.6 (8) angstrom 3, Z = 4, D(x) = 1.15 g cm-3 (198 K), Mo K-alpha radiation, lambda = 0.7107 angstrom, mu = 0.6734 cm-1, F(000) = 768, T = 198 K, R = 0.0547 for 1772 reflections [F(o) greater-than-or-equal-to 4-sigma-(F(o))]. Molecules are H-bonded into infinite columns parallel to a. The H bond involves the NH group and the carbonyl O atom of the carbamate moiety with relevant parameters: N11-H11...O13 (related by 1/2 + x, 1/2 - y, - z); N...O 2.910 (5), H...O 2.11 (5) angstrom, N-H...O 159 (4)-degrees.Robert A. Welch Foundation (F-626)National Institutes of Health (GM 31750)ChemistryBiochemistr

Cosmological Evolution of Global Monopoles

We investigate the cosmological evolution of global monopoles in the radiation dominated (RD) and matter dominated (MD) universes by numerically solving field equations of scalar fields. It is shown that the global monopole network relaxes into the scaling regime, unlike the gauge monopole network. The number density of global monopoles is given by $n(t) \simeq (0.43\pm0.07) / t^{3}$ during the RD era and $n(t) \simeq (0.25\pm0.05) / t^{3}$ during the MD era. Thus, we have confirmed that density fluctuations produced by global monopoles become scale invariant and are given by $\delta \rho \sim 7.2(5.0) \sigma^{2} / t^{2}$ during the RD (MD) era, where $\sigma$ is the breaking scale of the symmetry.Comment: 6 pages, 2 figures, to appear in Phys. Rev. D (R

Long term outcomes following hospital admission for sepsis using relative survival analysis: a prospective Cohort study of 1,092 patients with 5 year follow up

Background: Sepsis is a leading cause of death in intensive care units and is increasing in incidence. Current trials of novel therapeutic approaches for sepsis focus on 28-day mortality as the primary outcome measure, but excess mortality may extend well beyond this time period.Methods: We used relative survival analysis to examine excess mortality in a cohort of 1,028 patients admitted to a tertiary referral hospital with sepsis during 2007–2008, over the first 5 years of follow up. Expected survival was estimated using the Ederer II method, using Australian life tables as the reference population. Cumulative and interval specific relative survival were estimated by age group, sex, sepsis severity and Indigenous status.Results: Patients were followed for a median of 4.5 years (range 0–5.2). Of the 1028 patients, the mean age was 46.9 years, 52% were male, 228 (22.2%) had severe sepsis and 218 (21%) died during the follow up period. Mortality based on cumulative relative survival exceeded that of the reference population for the first 2 years post admission in the whole cohort and for the first 3 years in the subgroup with severe sepsis. Independent predictors of mortality over the whole follow up period were male sex, Indigenous Australian ethnicity, older age, higher Charlson Comorbidity Index, and sepsis-related organ dysfunction at presentation.Conclusions: The mortality rate of patients hospitalised with sepsis exceeds that of the general population until 2 years post admission. Efforts to improve outcomes from sepsis should examine longer term outcomes than the traditional primary endpoints of 28-day and 90-day mortality

Optimizing Fresh Specimen Staining for Rapid Identification of Tumor Biomarkers During Surgery.

Rationale: Positive margin status due to incomplete removal of tumor tissue during breast conserving surgery (BCS) is a prevalent diagnosis usually requiring a second surgical procedure. These follow-up procedures increase the risk of morbidity and delay the use of adjuvant therapy; thus, significant efforts are underway to develop new intraoperative strategies for margin assessment to eliminate re-excision procedures. One strategy under development uses topical application of dual probe staining and a fluorescence imaging strategy termed dual probe difference specimen imaging (DDSI). DDSI uses a receptor-targeted fluorescent probe and an untargeted, spectrally-distinct fluorescent companion imaging agent topically applied to fresh resected specimens, where the fluorescence from each probe is imaged and a normalized difference image is computed to identify tumor-target distribution in the specimen margins. While previous reports suggested this approach is a promising new tool for surgical guidance, advancing the approach into the clinic requires methodical protocol optimization and further validation. Methods: In the present study, we used breast cancer xenografts and receiver operator characteristic (ROC) curve analysis to evaluate a wide range of staining and imaging parameters, and completed a prospective validation study on multiple tumor phenotypes with different target expression. Imaging fluorophore-probe pair, concentration, and incubation times were systematically optimized using n=6 tissue specimen replicates per staining condition. Resulting tumor vs. normal adipose tissue diagnostic performance were reported and staining patterns were validated via receptor specific immunohistochemistry colocalization. Optimal staining conditions were tested in receptor positive and receptor negative cohorts to confirm specificity. Results: The optimal staining conditions were found to be a one minute stain in a 200 nM probe solution (area under the curve (AUC) = 0.97), where the choice of fluorescent label combination did not significantly affect the diagnostic performance. Using an optimal threshold value determined from ROC curve analysis on a training data set, a prospective study on xenografts resulted in an AUC=0.95 for receptor positive tumors and an AUC = 0.50 for receptor negative (control) tumors, confirming the diagnostic performance of this novel imaging technique. Conclusions: DDSI provides a robust, molecularly specific imaging methodology for identifying tumor tissue over benign mammary adipose tissue. Using a dual probe imaging strategy, nonspecific accumulation of targeted probe was corrected for and tumor vs. normal tissue diagnostic potential was improved, circumventing difficulties with ex vivotissue specimen staining and allowing for rapid clinical translation of this promising technology for tumor margin detection during BCS procedures

Evolution of a global string network in a matter dominated universe

We evolve the network of global strings in the matter-dominated universe by means of numerical simulations. The existence of the scaling solution is confirmed as in the radiation-dominated universe but the scaling parameter $\xi$ takes a slightly smaller value, $\xi \simeq 0.6 \pm 0.1$, which is defined as $\xi = \rho_{s} t^{2} / \mu$ with $\rho_{s}$ the energy density of global strings and $\mu$ the string tension per unit length. The change of $\xi$ from the radiation to the matter-dominated universe is consistent with that obtained by Albrecht and Turok by use of the one-scale model. We also study the loop distribution function and find that it can be well fitted with that predicted by the one-scale model, where the number density $n_{l}(t)$ of the loop with the length $l$ is given by $n_{l}(t) = \nu/[t^2 (l + \kappa t)^2]$ with $\nu \sim 0.040$ and $\kappa \sim 0.48$. Thus, the evolution of the global string network in the matter-dominated universe can be well described by the one-scale model as in the radiation-dominated universe.Comment: 10 pages, 5 figure

Coastal Bermudagrass Response to Limestone and Phosphorus

Last updated: 6/9/200

Annual Ryegrass Response to Limestone and Phosphorus

Last updated: 6/9/200