Concentration-dependent 4I13/2 lifetimes inEr3+-doped fibers and Er3+-doped planar waveguides

We report on the concentration- and pump-dependent lifetimes of the spontaneous emission in Er³⁺-doped fibers and Er³⁺ -doped waveguides. In addition, we measure the concentration dependence of the 550-nm fluorescence due to excited state absorption (ESA)     

The modified beta-ketoadipate pathway in Rhodococcus rhodochrous N75: enzymology of 3-methylmuconolactone metabolism

Rhodococcus rhodochrous N75 is able to metabolize 4-methylcatechol via a modified beta-ketoadipate pathway. This organism has been shown to activate 3-methylmuconolactone by the addition of coenzyme A (CoA) prior to hydrolysis of the butenolide ring. A lactone-CoA synthetase is induced by growth of R. rhodochrous N75 on p-toluate as a sole source of carbon. The enzyme has been purified 221-fold by ammonium sulfate fractionation, hydrophobic chromatography, gel filtration, and anion-exchange chromatography. The enzyme, termed 3-methylmuconolactone-CoA synthetase, has a pH optimum of 8.0, a native Mr of 128,000, and a subunit Mr of 62,000, suggesting that the enzyme is homodimeric. The enzyme is very specific for its 3-methylmuconolactone substrate and displays little or no activity with other monoene and diene lactone analogues. Equimolar amounts of these lactone analogues brought about less than 30% (most brought about less than 15%) inhibition of the CoA synthetase reaction with its natural substrate.     

Crystal morphology of mixtures of tripalmitin and butterfat

Blends of butterfat and tripalmitin are of interest for use as moisture barriers in edible films. Tripalmitin was blended with butterfat in the ratios 100:0, 90:10, 80:20, and so on through to 10:90 and 0:100. Crystal morphologies of squash and smear preparations were determined by polarizing light microscopy. Samples were stored at 19–22°C and re-examined after 6 d and after 30 d. Morphology was strongly dependent on composition and the presence of a coverslip. Morphology was less dependent on polymorphic form and age. Barrier properties depend more strongly on morphology than on polymorphic form.     

Modeling the adversary and success in competition.

Competition has been studied as something to be averted, yet rarely has it been asked what processes may be involved in successful competition. The authors tested whether more accurate modeling of an adversary can assist competitive success. Pairs played a zero-sum game with no specific skill component over 40 trials. The authors measured the relative accuracy of the players' second-order model (i.e., what I think about my opponent: R2MA) and third-order model (i.e., what I think my opponent thinks of me: R3MA), using responses to adjectives indicating personality traits. Performance correlated with both R3MA and having a better strategy (i.e., a better distribution of responses), but these variables contributed separately to performance variance. However, R2MA did not correlate with performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Home care aide retention: building team spirit to avoid employee walkouts

While home care agencies work to increase productivity and decrease costs, it is easy to lose sight of the value of employees. Because home care aides are seldom in the office, their value to the organization may get overlooked. In this article, one home care agency shares ways to build team spirit among the home care aides and empower them to be better employees. The result has been increased productivity, improved morale, and a more stable workforce.     

Proteolytic fragments of the Alzheimer's disease associated presenilins-1 and -2 are phosphorylated in vivo by distinct cellular mechanisms

The majority of familial Alzheimer's disease mutations are linked to the recently cloned presenilin (PS) genes, which encode two highly homologous proteins (PS-1 and PS-2). Full-length PS proteins undergo endoproteolytic cleavage within their hydrophilic loop domain resulting in the formation of C-terminal (CTF) and N-terminal fragments (NTF). PS-2 was found to be phosphorylated as a full-length protein within its N-terminal domain. In contrast, PS-1 is phosphorylated selectively after proteolytic processing within its approximately 20 kDa CTF involving protein kinase C (PKC) and/or protein kinase A (PKA). We now have found that the CTF of the highly homologous PS-2 is also phosphorylated. Surprisingly, the PS-2 CTF is not phosphorylated by PKC or PKA. Instead, the PS-2 CTF is constitutively phosphorylated in vivo by serine/threonine protein kinases, which are independent of phorbol ester and intracellular cAMP. In vitro the large hydrophilic loop of PS-2 between transmembrane domains 6 and 7 can be phosphorylated by casein kinase-1 (CK-1) and CK-2, but not by PKA or PKC. Quantitative analysis of in vitro phosphorylation demonstrates the presence of two phosphorylation sites for CK-1 and a single site for CK-2. A deletion analysis revealed that the CTF of PS-2 is phosphorylated in vivo within an acidic sequence containing three potential phosphorylation sites for CKs (serines 327, 330, and 335). These data suggest that CK type protein kinases phosphorylate the CTF of PS-2 within its hydrophilic loop domain in vivo. Interestingly, the potential phosphorylation sites are located directly adjacent to the recently identified caspase cleavage sites.     

Processing and Properties of Alumina-Graphite Platelet Composites

Fine-grain Al₂O₃-graphite platelet composites have been fabricated by both filter pressing and tape casting with up to 50 vol% of fine or coarse graphite flakes. Filter pressing behavior remains unchanged with coarse graphite flake additions. Strength of hot-pressed specimens decreases from about 350 to about 50 MPa with 50 vol% graphite. Preliminary experiments indicate that platelet orientation has a significant effect on strength: Platelets oriented perpendicular to the fracture plane and face-on to the crack front are about 20% weaker than composites with platelets oriented both perpendicular to the fracture plane and edge-on to the crack front. This suggests that the flakes behave as oriented voids in the microstructure.     

Investigations concerning the semihydrostatic emplacement of waste packages in vertical boreholes

The semihydrostatic emplacement of waste packages in unlined vertical boreholes in salt domes involves the uncontrolled deposition of the packages in the borehole and their complete enclosure in crushed salt. In order to calculate the pressure distribution in the backfilled borehole section, the borehole filling composed of packages and crushed salt is treated by approximation as a homogeneous medium in the theoretical model. The eigenvalues of the pressure tensor depend on the radial distance r from the borehole centre and on the depth z in the borehole and are thus directionally dependent. Emplacement-typical crushed-salt parameters such as lateral pressure coefficient and friction coefficients were experimentally determined. The calculations show that, according to the semihydrostatic model, the maximum pressure in the borehole does not exceed 107 kPa for a 4001 waste package, that this maximum pressure is already reached at a depth of 9.26 m on the borehole wall and that there is an optimum borehole radius for which stressing of the emplaced packages is minimized.