Physicomechanical Properties and Phase Composition of Unfired Periclase-Carbon Refractories Based on Modified Phenol-Formaldehyde Resin

Refractories and Industrial Ceramics - Possibilities for improving the physicomechanical properties of periclase-carbon materials by modifying phenol-formaldehyde resin (PFR) with organo-inorganic...     

The Effects of Sperm and Seminal Fluid of Immunized Male Mice on In Vitro Fertilization and Surrogate Mother–Embryo Interaction

The latest vaccination campaign has actualized the potential impact of antigenic stimuli on reproductive functions. To address this, we mimicked vaccination’s effects by administering keyhole limpet hemocyanin (KLH ) to CD1 male mice and used their sperm for in vitro fertilization (IVF). Two-cell embryos after IVF with spermatozoa from control (C) or KLH-treated (Im) male mice were transferred to surrogate mothers mated with vasectomized control (C) or KLH-treated (Im) male mice, resulting in four experimental groups: C–C, Im–C, C–Im, and Im–Im. The pre-implantation losses were significantly lower in the Im–C group than in the C–Im group. At the same time, the resorption rates reduced markedly in the C–Im compared to the Im–C group. Embryo and placenta weights were significantly higher in the Im–Im group. Although the GM-CSF levels were lower in the amniotic fluid of the gestating surrogate mothers in the Im–Im group, they were strongly correlated with embryo mass. The number–size trade-off was only significant in the Im–Im group. This suggests a positive, cooperative effect of spermatozoa and seminal fluid from immune-primed males on embryo growth and the optimal distribution of surrogate mother maternal resources despite the negative impact of males’ antigenic challenge on the IVF success rate.     

Structural Analysis of the Ancestral Haloalkane Dehalogenase AncLinB-DmbA

Haloalkane dehalogenases (EC 3.8.1.5) play an important role in hydrolytic degradation of halogenated compounds, resulting in a halide ion, a proton, and an alcohol. They are used in biocatalysis, bioremediation, and biosensing of environmental pollutants and also for molecular tagging in cell biology. The method of ancestral sequence reconstruction leads to prediction of sequences of ancestral enzymes allowing their experimental characterization. Based on the sequences of modern haloalkane dehalogenases from the subfamily II, the most common ancestor of thoroughly characterized enzymes LinB from Sphingobium japonicum UT26 and DmbA from Mycobacterium bovis 5033/66 was in silico predicted, recombinantly produced and structurally characterized. The ancestral enzyme AncLinB-DmbA was crystallized using the sitting-drop vapor-diffusion method, yielding rod-like crystals that diffracted X-rays to 1.5 Å resolution. Structural comparison of AncLinB-DmbA with their closely related descendants LinB and DmbA revealed some differences in overall structure and tunnel architecture. Newly prepared AncLinB-DmbA has the highest active site cavity volume and the biggest entrance radius on the main tunnel in comparison to descendant enzymes. Ancestral sequence reconstruction is a powerful technique to study molecular evolution and design robust proteins for enzyme technologies.     

Influential psychotherapy figures, authors, and books: An Internet survey of over 2,000 psychotherapists.

In a partial replication and extension of a survey conducted 25 years ago (Smith, 1982), over 2,400 North American psychotherapists completed a Web-based survey in which they identified prominent figures in the psychotherapy field who have most influenced their practice and the best psychotherapy books they had read in the past 3 years. There is a continued prominence to leaders of the field from 25 years ago but who are now deceased, notably the top-ranked Carl Rogers. Three books on the top-10 list represent empirically supported therapies (ESTs); two are treatment manuals for an EST, and one is a self-help book derived from an EST that has itself been shown to be efficacious bibliotherapy. Differences between psychologist and nonpsychologist therapists in the choice of influential figures, authors, and books are negligible. Implications are discussed in terms of the contemporary context into which therapeutic innovations are disseminated, as well as the conditions that may be necessary for successful dissemination. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Pathways of hydrogen photoproduction by immobilized Chlamydomonas reinhardtii cells deprived of sulfur

The green algae Сhlamydomonas reinhardtii entrapped in a thin alginate film have been shown to sustain elevated rates of hydrogen photoproduction under anaerobic incubation in sulfur/phosphorus depleted tris-acetate medium. In the present work we studied mechanisms, underlying hydrogen photoproduction by the immobilized culture, particularly, the roles of PSII and starch accumulation/breakdown. DCMU, a specific inhibitor of electron transport in PSII, is known to suppress hydrogen evolution by circa 80% in suspension cultures of S-deprived C. reinhardtii. In immobilized cells DCMU caused successive stimulatory and inhibitory effects on hydrogen photoproduction, both depending on the deprivation status of the algal cell. The inhibitory effect of DCMU was 25% at 70 h of S deficiency when maximal rates of hydrogen photoproduction were observed. Measurements of the light-induced prompt and delayed chlorophyll fluorescence transients and reflectance at 820 nm (P₇₀₀ redox transitions) revealed very rapid decline of PSII activity in the entrapped S-deprived cells as compared with the suspension culture, whereas PSI suffered less. The immobilized culture showed a high capacity to accumulate starch during early stages of S deprivation and relatively high rates of anaerobic starch degradation during the following hydrogen evolution period. DCMU partly inhibited starch breakdown. Results of the present work brought us to the conclusion that PSII-independent pathway of hydrogen evolution is elevated in the immobilized S-deprived cells rather due to the rapid inactivation of PSII, efficient starch catabolism and non-photochemical PQ reduction.     

Monomolecular enzyme films stabilized by amphiphilic polyelectrolytes for biosensor devices

This paper describes the use of new amphiphilic polyelectrolytes for protein immobilization. Monomolecular films of glucose oxidase (GO) and monoamine oxidase (MAO) stabilized by amphiphilic polyelectrolytes (polyethyleneimine and poly-4-vinylpyridine derivatives modified by lauryl chains) were formed on a water surface in a Langmuir-Blodgett trough. The compressed films containing the enzymes were transferred onto the surface of a polypropylene membrane of a Clark electrode according to the Langmuir-Schaefer method. The analytical responses of the resulting biosensors were linear over the range 1–10 mM of glucose and 8–100 μM of tyramine. Furthermore, direct functional coupling of GO and ferrocenecarboxylic acid in multilayer films stabilized by amphiphilic polyelectrolytes was demonstrated. The amperometric response of such a sensor was linear over the range 1–20 mM of glucose. The dependence of the kinetic parameters of the enzymes on the amphiphilic polyelectrolyte structures is discussed.