A relative of the catalytic subunit of cyclic AMP-dependent protein kinase in Aplysia spermatozoa.

Transcripts encoding CAPL-B, an apparent member of the cyclic-nucleotide-regulated kinase subfamily in Aplysia californica, are found exclusively in the ovotestis and are concentrated in meiotic and postmeiotic spermatogenic cells. The CAPL-B polypeptide is present in mature spermatozoa, suggesting that the kinase plays a part in regulating events associated with fertilization

A practical carbonation model for service life design of reinforced concrete structures

The “Durability Index” (DI) performance-based approach, developed in South Africa, involves the application of early-age concrete test methods together with service life prediction models, and links material properties directly with the expected service life of reinforced concrete (RC) structures under various environmental conditions. The Oxygen Permeability Index (OPI) DI test is based on permeation and relates to carbonation of concrete. As practised in South Africa (e.g. Committee of Transport Officials (COTO)), this approach requires durability considerations to be introduced in the design of the concrete mixture, and provides a quantification of the expected service life duration. This paper presents a design tool based on existing models for use in practical applications for service life design, assuming application of carbonation models and the OPI test method, and representing a probabilistic approach to performance-based durability design. The design tool can be applied for predicting the long-term performance of new RC structures as well as improving the basis for quality assessment of existing, newly built RC structures. This probabilistic approach to performance-based durability assessment is exemplified using actual data reported in the literature

Towards slender, innovative concrete structures for replacement of existing viaducts

A majority of the bridges and viaducts in the Netherlands were built in the sixties and seventies of the last century and many of them will need to be replaced in the near future due to technical or functional reasons. This is a replacement issue, faced by many countries worldwide. But what about the concrete structures? Should we replace them with the same structural systems and by using the same conventional concrete as used before? Or do we apply the newly developed concrete types, such as Ultra High Performance Concrete (UHPC) and Strain Hardening Cementitious Composites (SHCC) and install them with structural health monitoring techniques? In the paper the findings of several exploratory studies, performed at Delft University of Technology, are presented. In general, but especially for the replacement of existing structures, there is a tendency for increasing the slenderness of the concrete structures. In tenders it is even seen that contractors can get an increased bonus when building with reduced heights. A driving force is the fact that piers in roads are highly undesirable (freedom in space), while, in order to reduce additional costs, the new bridge should stay aligned with the existing roads. Most of the existing viaducts in the Netherlands are three or four span plate bridges with a total span between 20 and 60 m. Is it feasible to replace these by single span bridges with slenderness as high as 60? In a feasibility study, the possibilities for this are investigated and steps to be made are addressed. The exploratory study focuses on long, slender concrete structures, which can be obtained by applying Advanced Cementitious Materials (ACMs) while furthermore new building methods are explored. In general, the idea is to make steps towards our future SMART bridges for which structural health monitoring, sustainability, no hinder, zeroenergy, no maintenance and aesthetics are keywords

Catalytic subunits of Aplysia neuronal cAMP-dependent protein kinase with two different N termini.

Previously, two forms of cAMP-dependent protein kinase catalytic subunit generated by mutually exclusive use of two internal exon cassettes (A1 and A2) were demonstrated in Aplysia neurons. Here, it is shown that there also exist catalytic subunits with alternative N termini derived from two exons, N1 and N2, expressed in combination with either of the internal cassettes. Processed transcripts including N1 or N2 sequences are of about equal abundance in the nervous system, arise through alternative promoter use, and encode catalytically active polypeptides. The N2 amino acid sequence is 21 residues longer than the N1 sequence and is homologous to the nonmyristoylated N terminus of the TPK1 gene product, a yeast catalytic subunit homolog. These data support the view that cAMP-dependent protein kinase activity in Aplysia neurons is produced by a complex array of regulatory and catalytic subunits that generate multiple holoenzymes with a spectrum of properties

Chloride penetration resistance of fine recycled aggregate concrete

This study investigates the chloride penetration resistance of fine recycled aggregate concrete (FRAC). Six concrete mixes comprising 0.45 and 0.55 w/b were prepared using fine recycled aggregates (FRA) at 0, 25 and 50% by volume replacement of natural sand. The chloride penetration resistance of the concrete was tested using the surface electrical resistivity (SER), chloride conductivity index (CCI), and the bulk diffusion tests. The SER and CCI tests were conducted after 28 days and 180 days of wet curing, while the bulk diffusion test was carried out after 28 days of wet curing and 180 days of exposure to chloride solution. Results show that the SER of FRA concrete was comparable to the control concrete, at all ages tested. The 28-day CCI of the concrete was impacted as FRA replacement levels increased, whereas at 180 days of testing, the FRA concrete mixes showed more significant improvement in CCI than the control natural aggregate concrete (NAC). The bulk diffusion results indicate that, for each w/b, the chloride diffusion profiles of the control and FRA concrete are comparable