Peroxiredoxin-1 from the Human Hookworm Ancylostoma ceylanicum Forms a Stable Oxidized Decamer and Is Covalently Inhibited by Conoidin A

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Synthesis and properties of phosphinothricin derivatives

Abstract

The synthesis and properties of phosphinothricin derivatives which have different alkyl groups attached to phosphorus or bear a substituent on the nitrogen are described and their biological activities discussed.     

Entropy of isolated quantum systems after a quench

A diagonal entropy, which depends only on the diagonal elements of the system's density matrix in the energy representation, has been recently introduced as the proper definition of thermodynamic entropy in out-of-equilibrium quantum systems. We study this quantity after an interaction quench in lattice hard-core bosons and spinless fermions, and after a local chemical potential quench in a system of hard-core bosons in a superlattice potential. The former systems have a chaotic regime, where the diagonal entropy becomes equivalent to the equilibrium microcanonical entropy, coinciding with the onset of thermalization. The latter system is integrable. We show that its diagonal entropy is additive and different from the entropy of a generalized Gibbs ensemble, which has been introduced to account for the effects of conserved quantities at integrability.     

The Superacid HBr/AlBr3: Protonation of Benzene and Ordered Crystal Structure of [C6H7]+[Al2Br7]−

Crystalline and properly ordered protonated benzene as the [C₆H₇]⁺[Al₂Br₇]^??(C₆H₆) salt 1 are obtained by the combination of solid AlBr₃, benzene, and HBr gas. Compound 1 was characterized and verified by NMR, Raman and X‐Ray spectroscopy. This unexpected simple and straight forward access shows that HBr/AlBr₃ is an underestimated superacid that should be used more frequently.     

Programmed Self‐Assembly of a Quadruplex DNA Nanowire

The ability to produce, reproducibly and systematically, well‐defined quadruplex DNA nanowires through controlled rational design is poorly understood despite potential utility in structural nanotechnology. The programmed hierarchical self‐assembly of a long four‐stranded DNA nanowire through cohesive self‐assembly of GpC and CpG “sticky” ends is reported. The encoding of bases within the quadruplex stem allows for an uninterrupted π‐stacking system with rectilinear propagation for hundreds of nanometers in length. The wire is mechanically stable and features superior nuclease resistance to double‐stranded DNA. The study indicates the feasibility for programmed assembly of uninterrupted quadruplex DNA nanowires. This is fundamental to the systematic investigation of well‐defined DNA nanostructures for uses in optoelectronic and electronic devices as well as other structural nanotechnology applications.     

Comparison between experiment and computer modeling for simple MILOconfigurations

The MILO is a crossed-field HPM, high power microwave source which uses its self-generated magnetic field to cut off electron flow to the anode. A detailed comparison of experimental results and a computer simulation has been made for a number of simple axisymmetric MILO structures designed to operate at 1 GHz. The structures were built from demountable components which enabled the number of cavities and their dimensions to be rapidly altered. Measurements were made of the fluctuating magnetic fields at the end of each cavity. The amplitude and depth of RF modulation of the magnetic fields, although repeatable, changed drastically from one configuration to the next; these parameters were compared with predictions from VIPER, a 2-D electromagnetic PIC code. Good quantitative agreement was obtained between experiments and the simulation in most situations, although, late in the current pulse, after about 100 ns, the level of RF began to decay; a phenomenon which became more pronounced as the applied voltage was increased. The decay was attributed to plasma formation on the cavity vanes and subsequent electron emission; this explanation was verified by computer modeling electron emission and by using vanes make from polished stainless steel in place of aluminum vanes     

Eine Apparatur zur automatischen Bestimmung von Wasserdampf-Sorptions-Isothermen und -Isobaren

An apparatus for the automatic determination of water vapor sorption isotherm and isobares is described. Its main parts are a Cahn electrobalance and a gas circulating system. The gas can be held at constant dew points between – 85 and + 25 degree by an ultracryostal and an ultrathermostate and brings the sorbens to hygroscopic equilibrium.     

The relationship between the efficiency of orthopedic wards and the socio-economic status of their patients

The purpose of this paper is to study the effect of the socio-economic status of patients on the efficiency of orthopedic wards in acute hospitals in Israel (20 hospitals), from the viewpoint of the regulator—Israel Ministry of Health. At the first stage, data envelopment analysis is used with two inputs, and three outputs, where one output is undesirable—“number of deaths”—which also reflects the quality of the health services. At the second stage, various nonparametric tests are utilized to test the relationship between the socio-economic status of patients and the efficiency. As by-product DEA provides benchmark analysis, which indicates the peers of each inefficient ward, and the I/O improvements are needed for achieving efficiency. Two versions of DEA were used: the output oriented version (variable returns to scale), and the non-oriented version (Additive). Further analysis provides comparison of the results with other simple efficiency measures. We also compare between the efficiency from the regulator viewpoint and the hospitals’ viewpoint.     

Methionine ligand lability of type I cytochromes c: detection of ligand loss using protein film voltammetry

Protein film voltammetry (PFV) is used to interrogate the behavior of a variety of bacterial and mitochondrial His/Met-ligated cytochromes c. While analogous studies upon alkanethiol-modified gold electrodes reveal the anticipated Fe(II/III) couple only, PFV using pyrolytic graphite edge (PGE) electrodes demonstrates the presence of a lower-potential form of each of the cyts c studied, with a potential of approximately -100 mV (vs hydrogen). The generation of the novel, lower-potential state is shown to arise specifically from the interaction with the PGE electrode. Simultaneously, the typical Fe(II/III) couple can be observed. PFV of a series of wild-type cytochromes and mutants in the Met-donating loop show that the lower-potential state is highly similar between proteins from Pseudomonas aeruginosa (PA), Hydrogenobacter thermophilus (HT), and horse heart. The generation of the lower-potential form correlates inversely with the stability of the Met-Fe interaction for each of the cytochromes. Comparison with chemically unfolded cyts c indicates that the lower-potential forms detected here are unique, and this distinct state is ascribed to the loss of the Met ligand. Thus, PGE is demonstrated to be a non-innocent electrode surface in PFV studies of His/Met-ligated cytochromes c.     

Rationally designed pincer-type heck catalysts bearing aminophosphine substituents: Pd IV intermediates and palladium nanoparticles

The aminophosphine-based pincer complexes [C6H3-2,6-(XP(piperidinyl)2)2Pd(Cl)] (X=NH 1; X=O 2) are readily prepared from cheap starting materials by sequential addition of 1,1',1'-phosphinetriyltripiperidine and 1,3-diaminobenzene or resorcinol to solutions of [Pd(cod)(Cl)2] (cod=cyclooctadiene) in toluene under N2 in "one pot". Compounds 1 and 2 proved to be excellent Heck catalysts and allow the quantitative coupling of several electronically deactivated and sterically hindered aryl bromides with various olefins as coupling partners at 140 degrees C within very short reaction times and low catalyst loadings. Increased reaction temperatures also enable the efficient coupling of olefins with electronically deactivated and sterically hindered aryl chlorides in the presence of only 0.01 mol % of catalyst. The mechanistic studies performed rule out that homogeneous Pd 0 complexes are the catalytically active forms of 1 and 2. On the other hand, the involvement of palladium nanoparticles in the catalytic cycle received strong experimental support. Even though pincer-type Pd IV intermediates derived from 1 (and 2) are not involved in the catalytic cycle of the Heck reaction, their general existence as reactive intermediates (for example, in other reactions) cannot be excluded. On the contrary, they were shown to be thermally accessible. Compounds 1 and 2 show a smooth halide exchange with bromobenzene to yield their bromo derivatives in DMF at 100 degrees C. Experimental observations revealed that the halide exchange most probably proceeded via pincer-type Pd IV intermediates. DFT calculations support this hypothesis and indicated that aminophosphine-based pincer-type Pd IV intermediates are generally to be considered as reactive intermediates in reactions with aryl halides performed at elevated temperatures.