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Maintenance of health and physiological homeostasis is a synergistic process involving tight regulation of proteins, transcription factors and other molecular processes. The immune system consists of innate and adaptive immune cells that are required to sustain immunity. The presence of pathogens and tumour cells activates innate immune cells, in particular Natural Killer (NK) cells. Stochastic expression of NK receptors activates either inhibitory or activating signals and results in cytokine production and activation of pathways that result in apoptosis of target cells. Thus, NK cells are a necessary component of the immunological process and aberrations in their functional processes, including equivocal levels of NK cells and cytotoxic activity pre-empts recurrent viral infections, autoimmune diseases and altered inflammatory responses. NK cells are implicated in a number of diseases including chronic fatigue syndrome (CFS). The purpose of this review is to highlight the different profiles of NK cells reported in CFS patients and to determine the extent of NK immune dysfunction in subtypes of CFS patients based on severity in symptoms.

Room temperature X-ray photoelectron spectroscopy (XPS or ESCA) has been employed to investigate pure single crystals of yttrium aluminum perovskite (YAlO3 (YAP)) and YAlO3 doped with several rare earth elements, Y1-xLnxAlO3 (Ln = Pr, Er, Ho). XPS peak shapes of the main elements forming the YAP structure, in structures that have been doped with ions of varying oxidation states, are rationalized as a function of structural environment and the oxidation state of doping ions. The significant changes in chemical shifts and full widths at half-maximum of the signals are caused by doping and the presence of color centers. The most distinctive change in chemical shifts is observed for the O(1s) peaks. Annealing in H2/N2 atmosphere (1200 °C) changes the color of the sample, removing color centers due to relocation of oxygen ions in the structure. Although the total amount of oxygen in the samples does not change, the relative ratio of oxygen ions occupying two independent positions in the structure changes on annealing. Only in the case of YAlO3 without color centers is the composition of crystal close to the stoichiometric one. Also the Y(3d) and Al(2p) signals are shifted to higher binding energies for doped YAP crystals.

WE present the first comparative study of the uptake of metal ions by neurones, performed for Zn, Cr, Co, Mo, Al, Ni, Mn and Cd. The study reveals substantial differences in the uptake of different metals, under similar exposure procedures. In particular, we found very large uptakes for aluminium and molybdenum. We also found significant effects of excitatory substances, in particular kainate, as stimulants of uptake of some of the metals.

A self-induced wet dust collector operating at 8.7 m3/sec was evaluated at a crushing station in an underground hard rock mine. The new dust collector replaced a baghouse dust collector. The unit was evaluated for dust removal efficiency as a function of particle size. Performance also was assessed by comparing airborne respirable dust in the general area prior to and after installation of the new collector system. The use of cascade impactors and optical particle counters at the intake and the exhaust of the dust collector revealed a high efficiency (>90%) for particles greater than 2.0 µm in size. The efficiency dropped to approximately 70% and 25% for 1.0 µm and 0.5 µm particles, respectively. The overall respirable dust reduction in the immediate crusher vicinity was measured with 10-mm nylon cyclones and another type of personal dust sampler designed by the Mining Research Laboratory in Elliot Lake, Ontario. The results showed an average respirable dust reduction of 51% with a maximum of 64% in some areas. For respirable silica dust, the average reduction was higher at 70% with maxima of up to 79%.

The effect of a wet scrubber in controlling long-lived and short-lived radionuclides associated with airborne particulate matter in the submicron and respirable ranges was investigated during hard-rock crushing operations at a crusher plant located in an underground uranium mine. Dust-loaded air from crushing operations was fed to the wet scrubber via an intake plenum and ducting system. Measurements were made of long-lived radioactive dust concentration and radon progeny and thoron progeny concentrations. Mineral dust and radioactive dust-size distributions also were determined by means of eight-stage cascade impactors. Measurements were conducted preferentially at the crusher platform, the scrubber, and in an area adjacent to the crusher. The data show the wet scrubber was very efficient in reducing the concentration of long-lived radioactive dust and in removing radioactive particulate matter of size greater than about 2 µm. A modest reduction in radon progeny and thoron progeny concentration also was noticed during the operation of the wet scrubber. The data indicate the wet scrubber tested was very efficient in controlling long-lived radioactive dust concentrations in underground uranium mine operations.

Thermogravimetric and differential thermal analyses of mesoporous zirconias obtained from anionic surfactants by a scaffolding mechanism reveal interesting differences between the samples prepared from long-chain sulfates or sulfonates, which lose their hydration water in two steps, and those obtained from long-chain phosphates for which dehydration occurs in one step. From the temperature of the tetragonal to monoclinic transition the molar volume of ZrO2 undergoing this transformation can be calculated. From the density and from the mesoporous volume (N2 adsorption), the thickness of the wall separating the elemental volumes of the mesoporous structure can be calculated as well as the pseudo-length of the pores. The calculated surface area of the mesopore fits nicely with the measured T-plot surface area for the sample calcined at 500 °C. For the sample dried at 140 °C, the agreement is not as good, probably because of a more disordered organization. The alkyl chain is tilted by about 57±10° with respect to the normal to the wall. Upon calcination the thickness of the wall increases to a point where crystallization in monoclinic zirconia occurs. At this point the mesoporous character is lost.