The reaction specificities of the pea and a cyanobacterial thylakoid processing peptidase are similar but not identical

AbstractThe thylakoid processing peptidase from the cyanobacterium Phormidium laminosum has been extracted from thylakoid membranes by solubilization with Triton X-100. Its reaction specificity has been compared with the analogous pea peptidase by processing in vitro of radiolabelled wheat and P. laminosum thylakoid lumenal precursor polypeptides. The cyanobacterial polypeptide is processed to the mature size through an intermediate by the P. laminosum peptidase, but to a polypeptide that has a slightly greater apparent molecular weight than the intermediate by the pea peptidase. Both peptidases correctly process the wheat polypeptide. This suggests that the reaction specificities of the two peptidases are similar, but not identical

On the capture width of wave energy converters

This paper extends the theory on capture width, a commonly used performance indicator for a wave energy converter (WEC). The capture width of a linear WEC is shown to depend on two properties: the spectral power fraction (a property introduced in this paper), which depends entirely on the sea state, and the monochromatic capture width, which is determined by the geometry of the WEC and the chosen power take off (PTO) coefficients. Each of these properties is examined in detail. Capture width is shown to be a measure of how well these two properties coincide. A study of the effects of PTO control on the capture width suggests that geometry control, a form of control that has not been the focus of much academic research, despite its use in the wave energy industry, deserves more attention. The distinction between geometry control and PTO control is outlined. While capture width is a valuable design tool, its limitations must be recognised. The assumptions made in the formulation of capture width are listed, and its limitations as a tool for estimating annual power capture of a WEC are discussed

Shrinkage and microstructural development during drying of organically modified silica xerogels

We have studied the different driving forces behind syneresis in MTES/TEOS gels by aging them in different H{sub 2}O/EtOH pore fluids. We show using shrinkage, density, contact angle, and N{sub 2} sorption measurements, the influence of gel/solvent interactions on the microstructural evolution during drying. Competing effects of syneresis (that occurs during aging) and drying shrinkage resulted in the overall linear shrinkage of the organically modified gels to be constant at {approximately}50%. Increasing the hydrophobicity of the gels caused the driving force for syneresis to change from primarily condensation reactions to a combination of condensation and solid/liquid interfacial energy. In addition the condensation driven shrinkage was observed to be irreversible, whereas the interfacial free energy driven shrinkage was observed to be partially reversible. Nitrogen sorption experiments show that xerogels with the same overall extent of shrinkage can have vastly different microstructures due to the effects of microphase separation

Isolated pores dissected from human two-pore channel 2 are functional

Multi-domain voltage-gated ion channels appear to have evolved through sequential rounds of intragenic duplication from a primordial one-domain precursor. Whereas modularity within one-domain symmetrical channels is established, little is known about the roles of individual regions within more complex asymmetrical channels where the domains have undergone substantial divergence. Here we isolated and characterised both of the divergent pore regions from human TPC2, a two-domain channel that holds a key intermediate position in the evolution of voltage-gated ion channels. In HeLa cells, each pore localised to the ER and caused Ca2+ depletion, whereas an ER-targeted pore mutated at a residue that inactivates full-length TPC2 did not. Additionally, one of the pores expressed at high levels in E. coli. When purified, it formed a stable, folded tetramer. Liposomes reconstituted with the pore supported Ca2+ and Na+ uptake that was inhibited by known blockers of full-length channels. Computational modelling of the pore corroborated cationic permeability and drug interaction. Therefore, despite divergence, both pores are constitutively active in the absence of their partners and retain several properties of the wild-type pore. Such symmetrical ‘pore-only’ proteins derived from divergent channel domains may therefore provide tractable tools for probing the functional architecture of complex ion channels

Induction and Amplification of Non-Newtonian Gravitational Fields

One obtains a Maxwell-like structure of gravitation by applying the weak-field approximation to the well accepted theory of general relativity or by extending Newton's laws to time-dependent systems. This splits gravity in two parts, namely a gravitoelectric and gravitomagnetic (or cogravitational) one. Due to the obtained similar structure between gravitation and electromagnetism, one can express one field by the other one using a coupling constant depending on the mass to charge ratio of the field source. Calculations of induced gravitational fields using state-of-the-art fusion plasmas reach only accelerator threshold values for laboratory testing. Possible amplification mechanisms are mentioned in the literature and need to be explored. The possibility of using the principle of equivalence in the weak field approximation to induce non-Newtonian gravitational fields and the influence of electric charge on the free fall of bodies are also investigated, leading to some additional experimental recommendations

Intelligent graphite core condition monitoring

Condition monitoring of graphite cores has increased significantly in recent years, as the safety cases required to continue operation of Advanced Gas Cooled Reactors (AGR) have evolved. This paper describes the development and implementation of intelligent systems designed to automate and formalise the CM analyses and tasks performed within the remit of the Monitoring Assessment Panels, which are currently being rolled out across the AGR fleet. The implementation of such systems is found to depend crucially on the involvement of station staff at each step of design and implementation, which is highlighted by the successful deployment of second iterations of the IMAPS system for managing reactor observations and the BETA system for automatically analysing refuelling data. Though each system was initially based on an individual analysis or tasks, this paper describes more recent work to allow closer integration of the systems as they are developed, in order to maximise the use of the available data while minimising duplication of effort and required operator time

Relativistic Coulomb Sum Rules for (e,e′)(e,e^\prime)

A Coulomb sum rule is derived for the response of nuclei to $(e,e^\prime)$ scattering with large three-momentum transfers. Unlike the nonrelativistic formulation, the relativistic Coulomb sum is restricted to spacelike four-momenta for the most direct connection with experiments; an immediate consequence is that excitations involving antinucleons, e.g., $N{\bar N}$ pair production, are approximately eliminated from the sum rule. Relativistic recoil and Fermi motion of target nucleons are correctly incorporated. The sum rule decomposes into one- and two-body parts, with correlation information in the second. The one-body part requires information on the nucleon momentum distribution function, which is incorporated by a moment expansion method. The sum rule given through the second moment (RCSR-II) is tested in the Fermi gas model, and is shown to be sufficiently accurate for applications to data.Comment: 32 pages (LaTeX), 4 postscript figures available from the author

Effects of acute cannabidiol on behavior and the endocannabinoid system in HIV-1 Tat transgenic female and male mice

Background: Some evidence suggests that cannabidiol (CBD) has potential to help alleviate HIV symptoms due to its antioxidant and anti-inflammatory properties. Here we examined acute CBD effects on various behaviors and the endocannabinoid system in HIV Tat transgenic mice. Methods: Tat transgenic mice (female/male) were injected with CBD (3, 10, 30 mg/kg) and assessed for antinociception, activity, coordination, anxiety-like behavior, and recognition memory. Brains were taken to quantify endocannabinoids, cannabinoid receptors, and cannabinoid catabolic enzymes. Additionally, CBD and metabolite 7-hydroxy-CBD were quantified in the plasma and cortex. Results: Tat decreased supraspinal-related nociception and locomotion. CBD and sex had little to no effects on any of the behavioral measures. For the endocannabinoid system male sex was associated with elevated concentration of the proinflammatory metabolite arachidonic acid in various CNS regions, including the cerebellum that also showed higher FAAH expression levels for Tat(+) males. GPR55 expression levels in the striatum and cerebellum were higher for females compared to males. CBD metabolism was altered by sex and Tat expression. Conclusion: Findings indicate that acute CBD effects are not altered by HIV Tat, and acute CBD has no to minimal effects on behavior and the endocannabinoid system