The aldehyde inhibitor Z-Ala-Ala-Phe-CHO has been synthesized and shown by (13)C-NMR to react with the active site serine hydroxyl group of alpha-chymotrypsin to form two diastereomeric hemiacetals. For both hemiacetals oxyanion formation occurs with a pKa value of ~7 showing that chymotrypsin reduces the oxyanion pKa values by ~5.6 pKa units and stabilizes the oxyanions of both diastereoisomer...

BACKGROUND Amyloid fibril formation is the hallmark of many human diseases, including Alzheimer's disease, type II diabetes and amyloidosis. Amyloid fibrils deposit in the extracellular space and generally co-localize with the glycosaminoglycans (GAGs) of the basement membrane. GAGs have been shown to accelerate the formation of amyloid fibrils in vitro for a number of protein systems. The high...

Avian frugivores have been somewhat poorly studied with regards to the effects that different fruit sugar types and concentrations have on their digestive efficiencies. Therefore, two relatively large South African frugivores, the Knysna turaco (Tauraco corythaix) and the purple-crested turaco (Gallirex porphyreolophus), were fed artificial fruit that contained equicaloric and equimolar concent...

Hydrothermal zinc oxide (ZnO) thick films were successfully grown on the chemical vapor deposition (CVD)-grown thick ZnO seed layers on a-plane sapphire substrates using the aqueous solution of zinc nitrate dehydrate (Zn(NO3)2). The use of the CVD ZnO seed layers with the flat surfaces seems to be a key technique for obtaining thick films instead of vertically aligned nanostructures as reported...

This paper describes the characterization and leaching behaviour of precious metal present from electronics scrap to obtain liquor which can be treated through hydrometallurgical techniques to purify the metals. The results of this study points out the technical feasibility of the recovery of the metals. The blank sample was characterized by X-ray florescence. This paper will also present the r...

This paper evaluates the effect of mix design parameters on mechanical, hydraulic, and durability properties pervious geopolymer concrete (PGC) made with a 3:1 blend granulated blast furnace slag (GBFS) fly ash (FA). A total nine PGC mixtures were designed using Taguchi method, considering four factors, each at three levels, namely, binder content, dune sand addition, alkaline-activator solutio...

Soil water repellency (SWR) was studied in 64 surface soil samples from Tenerife (Canary Islands, Spain), distributed over three different plant communities (natural and afforested Canarian pine forest, and high mountain legume scrub) and three types of soil parent materials (basaltic and salic rocks and basaltic tephra). Soils were studied for physicochemical properties (soil pH and salinity, ...

We recorded from lobster and leech neurons with two sharp electrodes filled with solutions often used with these preparations (lobster: 0.6 M K2SO4 or 2.5 M KAc; leech: 4 M KAc), with solutions approximately matching neuron cytoplasm ion concentrations, and with 6.5 M KAc (lobster, leech) and 0.6 M KAc (lobster). We measured membrane potential, input resistance, and transient and sustained depo...

The ability to understand and implement calculations required for molarity and dilution computations that are routinely undertaken in the laboratory are essential skills that should be possessed by all students entering an undergraduate Life Sciences degree. However, it is increasingly recognized that the majority of these students are ill equipped to reliably carry out such calculations. There...