Stress analysis of a simplified compression plate fixation system for fractured bones

A three-dimensional finite element model was generated of a plexiglass tube with an attached six-hole stainless steel compression plate to study the mechanics of internal fixation of fractured long bones. To demonstrate the importance of the plate-bone interface, this interface was represented three different ways in the finite element model. A plated tube with a uniform transverse osteotomy gap was also examined to study the mechanics of plated fractured bones. To validate the model, the results for the intact plated tube were compared to composite beam theory and strain gauge data from an instrumented physical model. Applications of the finite element model data included the prediction of screw failure modes, plate-induced osteopenia, and multi-axial strains in an interfragmentary region. The addition of sliding motion between the plate and tube resulted in a deviation from composite beam theory and improved correspondence with strain gage data when compared to a model having the plate and tube securely bonded. Sliding motion resulted in a much smaller region of bone subjected to reduced axial stress levels, which may decrease the extent of plate-induced osteopenia. The complex nature of induced strains in an osteotomy gap was also demonstrated, along with the tendency for failure of the screws nearest the fracture site.     

ANALYSIS OF DIACETYL AND RELATED COMPOUNDS IN FERMENTATIONS

A number of British beers have been analysed for diacetyl, 2,3-pentanedione, and related compounds. Finished beers contained little or no α-acetohydroxyacids or diketone bisulphite addition compounds. Sources of error in measuring the diketones by g.l.c. or by the Institute of Brewing Recommended Methods are discussed, and a special study is made of methods of assaying for α-acetolactic acid. Even under oxidizing conditions some acetoin is formed from α-acetolactic acid.     

Wetting delay due to film and transition boiling on hot surfaces

The time to achieve wetting of hot rods in air by a hot water jet was found to be a very strong function of water subcooling, and a strong function of jet velocity, surface thermal conductivity, heat generation rate, jet impact angle and surface temperature. Surface finish and rod size had little effect. The results agree with a simple model considering forced convection film boiling, heat generation and heat conduction from the surrounding surface.     

Correlation Loss with Optimized Receiver Delay for Band-Limited Communication

The degradation in correlation receiver performance due to signal distortion at the transmitting antenna is computed as a function of processing delay for simple but representative models of the Sanguine antenna and input waveforms. The optimum delay and minimum distortion loss are given parametrically in terms of the ratio of the 3 dB bandwidth of the signal process to that of the antenna. For the more realistic model considered the degradation can be reduced significantly to just a fraction of a dB by optimizing the receiver delay.     

USE OF FORMALDEHYDE FOR THE REDUCTION OF THE ANTHOCYANOGEN CONTENT OF WORT*,†

Reduction in wort anthocyanogen content is achieved effectively when formaldehyde is introduced to the mash at the beginning of the mashing operation. Concentrations of 50 p.p.m. of formaldehyde with respect to the malt (equivalent to about 5 p.p.m. with respect to the final wort volume) are effective in reducing the anthocyanogen content by about 30%. Treatments four times as strong reduce the anthocyanogen content by 60–70%, and the effect is accompanied by a fall of up to 10% in the soluble nitrogen content of the wort. It seems likely that a condensation reaction occurs between anthocyanogens and a nitrogenous fraction of the wort. Under the conditions quoted, formaldehyde residues in the finished beers are less than 0·2 p.p.m. and are no greater than those observed in corresponding untreated control beers. Beers produced from treated mashes exhibit great non-biological stability, but are quite normal in other respects. The effect of formaldehyde on the anthocyanogen contents of worts and beers is of substantial theoretical interest and it is probable that it will also have a commercial application.     

Involuntarily committed patients' constitutional right to refuse treatment: A challenge to psychology.

Discusses the constitutional basis of a right to refuse psychological intervention and its impact on psychological intervention. Federal courts have recently addressed the question of whether the US Constitution protects individuals from receiving unwanted medication with psychotropic drugs. In concluding that it does, these cases may provide the 1st step in the development of a constitutional right of psychiatric patients to refuse a variety of psychological treatments. One result of such a development is likely to be an increased demand by patients for nonmedical treatments for psychological disorders and a concomitant greater role for the profession of psychology in providing care for committed individuals. (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)