pH dependence of the multiline, manganese EPR signal for the ‘S2’ state in PS II particles Absence of proton release during the S1 → S2 electron transfer step of the oxygen evolving system

AbstractThe pH dependence of oxygen evolution rates, 2,6-dichlorophenolindophenol (DCIP) reduction rates and the intensity of the multiline manganese EPR signal associated with the S2 Kok state has been studied using oxygen-evolving spinach (PS) II particles. The oxygen evolution and DCIP reduction rates are found to be very sensitive to pH, with the maximal rates occuring at pH 6.5–7.0. Both the rate and yield of the S1 multiline manganese EPR signal intensity, produced by single flash excitation at room temperature or by continuous illumination at 200 K, are found to be independent of pH, indicating that no proton is released from this manganese site during the S1 → S1 electron transfer. These results agree with those from other laboratories showing no proton release on this transition, but using techniques monitoring other species

Physico-chemical Studies of Ternary Chelates in Solution: Part I -Potentiometric Study of Ni(II)-Glycine-Phenylacetohydroxamic Acid System

899-90

Nanoparticle Solar Cell Final Technical Report

The purpose of this work was to demonstrate all-inorganic nanoparticle-based solar cells with photovoltaic performance extending into the near-IR region of the solar spectrum as a pathway towards improving power conversion efficiencies. The field of all-inorganic nanoparticle-based solar cells is very new, with only one literature publication in the prior to our project. Very little is understood regarding how these devices function. Inorganic solar cells with IR performance have previously been fabricated using traditional methods such as physical vapor deposition and sputtering, and solution-processed devices utilizing IR-absorbing organic polymers have been investigated. The solution-based deposition of nanoparticles offers the potential of a low-cost manufacturing process combined with the ability to tune the chemical synthesis and material properties to control the device properties. This work, in collaboration with the Sue Carter research group at the University of California, Santa Cruz, has greatly expanded the knowledge base in this field, exploring multiple material systems and several key areas of device physics including temperature, bandgap and electrode device behavior dependence, material morphological behavior, and the role of buffer layers. One publication has been accepted to Solar Energy Materials and Solar Cells pending minor revision and another two papers are being written now. While device performance in the near-IR did not reach the level anticipated at the beginning of this grant, we did observe one of the highest near-IR efficiencies for a nanoparticle-based solar cell device to date. We also identified several key parameters of importance for improving both near-IR performance and nanoparticle solar cells in general, and demonstrated multiple pathways which showed promise for future commercialization with further research

A novel ciprofloxacin-resistant subclade of H58 Salmonella Typhi is associated with fluoroquinolone treatment failure.

The interplay between bacterial antimicrobial susceptibility, phylogenetics and patient outcome is poorly understood. During a typhoid clinical treatment trial in Nepal, we observed several treatment failures and isolated highly fluoroquinolone-resistant Salmonella Typhi (S. Typhi). Seventy-eight S. Typhi isolates were genome sequenced and clinical observations, treatment failures and fever clearance times (FCTs) were stratified by lineage. Most fluoroquinolone-resistant S. Typhi belonged to a specific H58 subclade. Treatment failure with S. Typhi-H58 was significantly less frequent with ceftriaxone (3/31; 9.7%) than gatifloxacin (15/34; 44.1%)(Hazard Ratio 0.19, p=0.002). Further, for gatifloxacin-treated patients, those infected with fluoroquinolone-resistant organisms had significantly higher median FCTs (8.2 days) than those infected with susceptible (2.96) or intermediately resistant organisms (4.01)(pS. Typhi clade internationally, but there are no data regarding disease outcome with this organism. We report an emergent new subclade of S. Typhi-H58 that is associated with fluoroquinolone treatment failure

Hexacoordinated Ternary Chelates of Cu(II) with Amino Acids

1038-104

Stress Waves in Nonhomogeneous Elastic Rods

Longitudinal wave propagation in a nonhomogeneous semi infinite elastic rod is considered. The non homogeneity may be due to the axial variation of Young\u27s modulus or of density or of both. An arbitrary time dependent stress is applied at the end, x = 0, of the rod. The normal stress as a function of position and time is obtained using the theory of the propagating surfaces of discontinuity by expanding the stress as a Taylor series about the time of arrival of the wavefront. The coefficients of the Taylor expansion are obtained as solutions of linear ordinary differential equations with variable coefficients. For the case where the Young\u27s modulus E(x) varies as (1 + ax)2a, it is shown that the stress at the wavefront varies as (1 + ax)⋔±, where a and ⋔± are constants. © 1966, Acoustical Society of America. All rights reserved