Vibrational spectroscopy studies of the role of water in metal ion extraction into room temperature ionic liquids

In efforts to evaluate the suitability of ionic liquids (ILs) as solvents for the extraction of fission products, two series of room temperature ILs, one comprising a diakylimidazolium cation and the other containing an analogous (1-hydroxyalkyl)-functionalized imidazolium cation, have been prepared as their bis[(trifluoromethyl)sulfonyl]imide salts. The extraction of Sr(II) from aqueous nitric acid solutions by dicyclohexano-18-crown-6 into these ILs has been measured. A linear correlation has been observed between the extent of Sr(II) extraction and the equilibrium water content of the IL phases. Although a precedence has been established similarly with n-alcohol diluents, the relationship in extraction systems employing IL diluents has yet to be adequately studied.To investigate how water may be functioning in these biphasic systems, vibrational spectroscopy has been employed. A challenge to this analysis has been to differentiate between the vibrational modes of water and those of the of IL diluents. Raman spectroscopy offers the possibility to distinguish between -OH vibrational modes from solvent moieties and those in a different state, such as molecular water. Along with the near-IR and mid-IR ranges, Raman spectroscopy is being utilized the interrogate states of molecular water and other species that may be involved in metal ion partitioning. With the ultimate goal of elucidating the interactions between IL constituent ions, metal ion-crown ether complexes, co-extracted ions (e.g., nitrate) and water, these studies represent a principal step in gaining a better understanding of partitioning mechanisms in IL-based separation media

The data vortex, an all optical path multicomputer interconnection network

Abstract—All optical path interconnection networks employing dense wavelength division multiplexing can provide vast improvements in supercomputer performance. However, the lack of efficient optical buffering requires investigation of new topologies and routing techniques. This paper introduces and evaluates the Data Vortex optical switching architecture which uses cylindrical routing paths as a packet buffering alternative. In addition, the impact of the number of angles on the overall network performance is studied through simulation. Using optimal topology configurations, the Data Vortex is compared to two existing switching architectures—butterfly and omega networks. The three networks are compared in terms of throughput, accepted traffic ratio, and average packet latency. The Data Vortex is shown to exhibit comparable latency and a higher acceptance rate (2x at 50 percent load) than the butterfly and omega topologies. Index Terms—Optical switch fabrics, optical switching, photonic packet switch, data vortex switch architecture, packet switching. Ç

Computational Study of Molecular Structure and Self-Association of Tri‑<i>n</i>‑butyl Phosphates in <i>n</i>‑Dodecane

Tri-<i>n</i>-butyl phosphate (TBP) is an important extractant used in the solvent extraction process for recovering uranium and plutonium from used nuclear fuel. An atomistic molecular dynamics study was used to understand the fundamental molecular-level behavior of extracting agents in solution. Atomistic parametrization was carried out using the AMBER force field to model the TBP molecule and <i>n</i>-dodecane molecule, a commonly used organic solvent. Validation of the optimized force field was accomplished through various thermophysical properties of pure TBP and pure <i>n</i>-dodecane in the bulk liquid phase. The mass density, dipole moment, self-diffusion coefficient, and heat of vaporization were calculated from our simulations and compared favorably with experimental values. The molecular structure of TBPs in <i>n</i>-dodecane at a dilute TBP concentration was examined based on radial distribution functions. 1D and 2D potential mean force studies were carried out to establish the criteria for identifying TBP aggregates. The dimerization constant of TBP in the TBP/<i>n</i>-dodecane mixture was also obtained and matched the experimental value

Validity of age estimates from muskellunge (Esox masquinongy) fin rays and associated effects on estimates of growth

Accurate age estimates are critical for understanding life histories of fishes and developing management strategies for fish populations. However, validation of age estimates requires known-age fish, which are often lacking. We used known-age (ages 1â 25) muskellunge (Esox masquinongy) to determine the precision and accuracy of age estimates from fin rays. We also determined if fin location (anal or pelvic), fin ray number, and preparation methods affected accuracy and precision. Lastly, we determined if von Bertalanffy growth parameters estimated from fin ray ages were similar to parameters estimated from known ages. Precision and accuracy of age estimates from anal and pelvic rays were similar and estimates were relatively precise (coefficient of variation = 8.5%) and accurate (mean absolute difference from known age = 0.85 y) for ages 4â 15, but ages were overestimated for younger fish and underestimated for older fish. Growth models based on estimated age were similar to models based on known age. Anal and pelvic rays offer a non-lethal alternative for age estimation of muskellunge ages 4â 15, and for producing reliable estimates of growth.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Profiling the Specificity of Neutralizing Antibodies in a Large Panel of Plasmas from Patients Chronically Infected with Human Immunodeficiency Virus Type 1 Subtypes B and C▿ †

Identifying the viral epitopes targeted by broad neutralizing antibodies (NAbs) that sometimes develop in human immunodeficiency virus type 1 (HIV-1)-infected subjects should assist in the design of vaccines to elicit similar responses. Here, we investigated the activities of a panel of 24 broadly neutralizing plasmas from subtype B- and C-infected donors using a series of complementary mapping methods, focusing mostly on JR-FL as a prototype subtype B primary isolate. Adsorption with gp120 immobilized on beads revealed that an often large but variable fraction of plasma neutralization was directed to gp120 and that in some cases, neutralization was largely mediated by CD4 binding site (CD4bs) Abs. The results of a native polyacrylamide gel electrophoresis assay using JR-FL trimers further suggested that half of the subtype B and a smaller fraction of subtype C plasmas contained a significant proportion of NAbs directed to the CD4bs. Anti-gp41 neutralizing activity was detected in several plasmas of both subtypes, but in all but one case, constituted only a minor fraction of the overall neutralization activity. Assessment of the activities of the subtype B plasmas against chimeric HIV-2 viruses bearing various fragments of the membrane proximal external region (MPER) of HIV-1 gp41 revealed mixed patterns, implying that MPER neutralization was not dominated by any single specificity akin to known MPER-specific monoclonal Abs. V3 and 2G12-like NAbs appeared to make little or no contribution to JR-FL neutralization titers. Overall, we observed significant titers of anti-CD4bs NAbs in several plasmas, but approximately two-thirds of the neutralizing activity remained undefined, suggesting the existence of NAbs with specificities unlike any characterized to date