Applications of Frontal Affinity Chromatography to the Study of Interactions between Metal Ions and a Complex Biomaterial

The use of frontal affinity chromatography for the study of metal-biomaterial interactions is described. Both normal frontal affinity chromatography and a modification of this methodology were used to generate metal binding isotherms to a biomaterial. This modification enabled the acquisition of binding isotherms with extended concentration ranges at the expense of time-dependent binding information. Comparison between normal and modified mode was made by using a well-defined commercial resin. Similar performance of these two modes was obtained. The biomaterial investigated was composed of cell fragments from the plant Datura innoxia which were immobilized within a polysilicate matrix. The application of a regularized least-squares method indicated the existence of two classes of sites on this biosorbent involved in the binding of Ag(+). A total metal-ion binding affinity order at solution pH 3-5 was determined to be Cu(2+) > Cd(2+) ≈ Ag(+) > Ca(2+).     

Artefacts as designed, artefacts as used: resources for uncovering activity dynamics

This paper addresses the use of artefacts as a powerful resource for analysis, focusing on the artefact as designed as a means of eliciting the designers explicit and implicit knowledge and artefacts as used as a means of uncovering the trail left by currently inactive processes. Artefact analysis is particularly suitable in situations where direct observation is ineffective, especially in activities that occur infrequently. We demonstrate the usefulness of our technique through the analysis of artefacts within both the office and the meeting environment. This is part of a wider study aimed at understanding the nature of decisions in meetings with the view of producing a tool to aid decision management and hence reduce rework. We conclude by drawing out some general lessons from our analysis, which reaffirms the intricate role that artefacts play in maintaining activity dynamics.

Resistance training and the enhancement of the gains in material-handling ability and physical fitness of British Army recruits during basic training

The aim was to evaluate the efficacy of a modified British Army basic training that included resistance training in improving material-handling performance and physical fitness, and to compare the modified training directly with the normal basic training. Forty-three males [19.2 (2.6) years of age, 1764 (72) mm in height, 73.0 (10.6) kg in mass] and nine females [19.1 (2.2) years, 1641 (67) mm, 62.0 (7.2) kg] performed the modified basic training. Testing occurred in the week before and in the final week of the 11-week basic training. Improvements with the modified training were observed for all six material-handling tests, including 8-12% for maximal box lifting, 15-19% for repetitive lifting and carrying and 9-17% for loaded marching (all p < 0.01), and other established measures of aerobic fitness, strength and kinanthropometric characteristics. Significantly greater improvements were observed for the modified training compared with the normal training in maximal box lift to 1.45 m (12.4 versus 1.7%, p < 0.01), 3.2 km loaded march performance with 15 kg (8.9 versus 3.6%, p < 0.05), estimated fat-free mass (4.2 versus 1.5%, p < 0.001), predicted VO(2max) (1 min(-1)) (9.3 versus 4.1%, p < 0.01) and dynamic lift to 1.45 m (15.5 versus 0.2%, p < 0.001). It was concluded that the improvements in material-handling ability and other aspects of physical fitness brought about in recruits by British Army basic training can be enhanced by the use of a physical training programme that includes a carefully designed resistance training element. Of particular note are the improvements shown in performance on material-handling tasks that require muscular strength, as these represent many of the tasks that soldiers encounter in their military careers.     

Competitive metal binding to a silicate-immobilized humic material

The investigation of the competitive binding of metal ions to a biogenic material comprised of organic peat immobilized in a polysilicate matrix was undertaken. This material was packed into 5.0mL bed-volume columns using 40-60mesh size particles. Two separate mixtures of metal ions were studied by monitoring the solution pH and the concentration of each metal in the effluent as a function of the volume of influent introduced to the material. These mixtures contained either the metal ions Ca(2+), Mg(2+), and Cu(2+) or the ions Cu(2+), Hg(2+), and Pb(2+). A general order of binding affinities was determined to be Mg(2+)相似文献   

Small-Scale Test Protocol for Firefighting Foams DEF(AUST)5706: Effect of Bubble Size Distribution and Expansion Ratio

The experimental program described in this paper sought to assess the suitability of the small scale DEF(AUST)5706 standard for measuring the suppression and burnback performance of Class B foams on pool fires. DEF(AUST)5706 is an Australian Defence standard mandatory for use by the Australian Navy, Army and Air Force. The test protocol required the measurement of the 3/4 control, extinguishment and 1/3 burnback times for a circular pan of aviation gasoline (AVGAS 100/130), 0.28 m² in surface area. The test program involved compressed-air foams (CAF) and aspirated foams of two expansion ratios, and employed two AFFF formulations: a 6% telomer concentrate and, to obtain base-line measurements, 3% PFOS FC-600 concentrate which was manufactured by the 3 M company prior to the PFOS phase out. At lower expansion (7:1), the aspirated and compressed-air foams demonstrated similar fire control performance, whilst more expanded (9:1) CAF was generally more efficient at extinguishing, but less efficient in controlling the fire. CAF formed a better seal over the fuel surface and at the hot pan walls, and these foams performed noticeably better than aspirated foam against fuel re-ignition. The paper links these observations with the underlying distributions of bubble sizes, which were measured and fitted to modified Rosin/Rammler cumulative volume distribution functions. We propose that a modified version of DEF(AUST)5706 be adopted as a universal small-scale test protocol.