Identification and characterization of the murine homologue of CD22, a B lymphocyte-restricted adhesion molecule

The human B lymphocyte-specific Ag, CD22, is a cell adhesion molecule expressed on the surface during a narrow window of B cell development, coincident with surface IgD. A ligand for CD22 has recently been identified on human T cells as the low molecular mass isoform of the leukocyte common Ag, CD45RO. CD22 has been reported to function in the regulation of both T and B cell activation in vitro. In this study, we report the isolation and expression of a molecular cDNA clone encoding the murine homologue of CD22, mCD22. Within their predicted protein sequences, murine and human sequences overall have 62% identity, which includes 18 of 20 extracellular cysteines and six of six cytoplasmic tyrosines. BHK cells transfected with mCD22 cDNA specifically adhere to resting and activated T lymphocytes and in addition bound activated, but not resting, B cells. Five Th clones were analyzed for their ability to adhere to mCD22; two Th0 clones and one Th1 clone bound CD22+ BHK transfectants, but not all T cell clones bound CD22+ cells: another Th1 clone and a Th2 clone did not. mCD22+ BHK transfectants were also specifically bound by the B cell-specific mAb, NIM-R6, demonstrating that this mAb is specific for murine CD22. Human cell lines expressing the counter-receptors for human CD22 were also examined for adhesion to the murine CD22 homologue; the epitope responsible for B cell adhesion to CD22 is conserved, whereas the T cell epitope binding to CD22 is not. The cDNA and mAb to murine CD22 will be useful for defining the in vivo function of CD22.     

The economics of energy efficiency for the poor—a South African case study

South Africa’s Reconstruction and Development Programme set ambitious goals for providing basic services to all, including housing and electrification. More efficient use of energy has the potential to socially and politically support these goals, particularly when it is targeted at low-income communities lacking adequate energy services. This paper examines the economics of energy efficiency for the urban poor from the perspective of society, utilities and poor consumers, using five example programmes. While the five energy efficiency programmes generally have significant economic and environmental benefits from a social perspective, they may not be as attractive to utilities and consumers. Also examined are the policy options for overcoming the significant barriers to energy efficiency, and ways government can bridge the gap between what is good for society and what is good for the electricity industry.     

The effect of additives on the thermal stability of poly(vinyl chloride)

The effect of a range of organic additives on the thermal stability of poly(vinyl chloride), both with and without a chloroparaffin extender, was studied using a number of experimental techniques. Of the additives used the best overall balance was provided by pentaerythritol, which increased stability when the extender was present and had no effect when it was absent. The congo red test emerged as the most suitable technique, being consistent and inexpensive and able to screen several additives simultaneously. Isothermal differential thermal analysis correlated with the congo red test but required more expensive equipment, was time-consuming and demanded good mixing of the poly(vinyl chloride) compound to give reproducible results. Thermogravimetry was not sufficiently sensitive and the heat stability test was the least useful of all.     

CAFTURE AND RECYCLE OF BYPASSING BUBBLE GAS IN A FLUIDIZED BED: THE “BUBBLE EATER”

The bubble eater is a device which can sense, capture, and recycle bubble gas in a bubbling fluidized bed. The theory describing the enhancement of reactant gas conversion are presented and illustrated by means of a numerical example.     

In vitro studies on the use of clay, clay minerals and charcoal to adsorb bovine rotavirus and bovine coronavirus

Rotaviruses are the leading cause and coronaviruses are the major contributors of acute gastroenteritis in the young of various mammalian and avian species. Despite numerous trials and decades of research, vaccines have limited efficacy particularly for calves. As an alternative method of controlling infection, we have investigated broad spectrum antiviral agents that are not discriminatory among various viruses. This report involves testing a variety of adsorbent agents including charcoal, clay, and clay minerals to adsorb rotavirus and coronavirus in vitro. Results revealed that all the adsorbent agents had good to excellent capability of adsorbing rotavirus and excellent capability of adsorbing coronavirus. Percent adsorptions ranged from 78.74% to 99.89% for rotavirus and 99.99% for coronavirus; while sand (negative control) was < 0.01%. A high affinity binding was present as determined by a low percent desorption (0.06-3.09%). However, the adsorbent bound virus complex retained, and may have actually enhanced, infectivity.     

The failure of an F/A-18 trailing edge flap hinge

During a flight over sea, the right-hand trailing-edge flap (TEF) from an RAAF F/A-18 separated. Although the flap was not recovered, the mode of failure suggested that the outboard hinge lug was first to fail. A fleet-wide inspection of the TEF outer hinge lugs disclosed two other cracked hinge lugs. Examination of these cracks revealed that they had propagated as the result of a combination of corrosion and fatigue, in that the corrosive environment appeared to have accelerated the fatigue crack growth rate. Laboratory experiments indicated that, in a salt solution, the 7050 aluminium alloy from which the lugs were manufactured is susceptible to corrosion fatigue and that the observed cracking matched that on the cracked lugs: corrosion fatigue was therefore suspected to have been a contributing factor in the unexpected failure. Quantitative fractography on the fatigue cracks, combined with several assumptions and deductions, including information about the failure size of the crack gained from witness marks found on the monoball bearing of the failed TEF, led to an estimate of the fatigue crack growth rate. This crack growth rate and the short service life clearly indicated the limitations of the then-current non-destructive inspection (NDI) technique, and a more sensitive inspection method was developed to assist in the maintenance of adequate RAAF flying hours between inspections. This failure investigation provided an excellent example of how fractography, laboratory experiments and NDI can be combined to determine a possible cause of failure and to establish remedial measures for the fleet.