Regional variation in the microhardness and mineral content of porcine long bones

Pig carcasses are frequently used as models for the human cadaver in the study of trauma and wound patterns. Limited availability and ethical concerns over the use of human tissue has meant that porcine bone is often used as a substitute for human bone in such studies. However, there is a lack of comprehensive mechanical data to make informed decisions on the choice of model to account for variations in the age, sex and body mass. In this study, variation in the properties of cortical bone along the length of the porcine humerus and ulna, from five female pigs aged over 36 months, was investigated by using Vickers microhardness tests. Transverse sections were taken from the proximal, mid and distal regions of the diaphyses, and tests were carried out in the anterior, medial, posterior, and lateral quadrants. Microhardness was also measured across the cortex from the periosteal to endosteal surfaces. Regional variation in mineral content was explored by analysing samples, taken immediately adjacent to the hardness tests, using Atomic Absorption Spectroscopy. Mechanical data are discussed in relation to mineral content, morphology and loading of the limbs, within a forensic context

Tentative basis for proposing final settlements under section 209 of the Transportation Act, 1920; Tentative basis for proposing settlements under section 209 of the Transportation Act, 1920

First, our rule is that in fixing the maximum amounts to be included in operating expenses for maintenance under the guaranty of section 209 of the Transportation Act, 1920, we will, as far as practicable, under the accounting test established by the proviso of section 5 of the standard contract, fix such amounts as would have resulted during the guaranty period in the same amount, character and durability of physical reparation as was applied to the respective carrier properties, during an average six months of the test period, three years ending June 30, 1917, making due allowance for differences in the amount and use of the properties involved. Second, in making the adjustments for changes in cost of labor consideration will be given to all changes of any character which affect in any way the labor cost of material in place, and will include not only changes in price of labor per payroll hour or other unit paid for, but also the relation of time paid for to effective time of work, differences in the efficiency and cost of labor due to changed personnel, and any other elements affecting the aggregate cost of labor necessary to effect the standard of maintenance observed by the carriers respectively during the test period. Third, in fixing the maximum maintenance allowance for the properties during the guaranty period, all charges representing depreciation and repairs will be computed upon the same bases for the guaranty period as were used in the test period. Fourth, and this fourth item now has reference to the accounting test; as I stated to the Committee on General Accounts about a year ago, and as was indicated by Commissioner Meyer yesterday, the adjustments provided in Section 209 are adjustments of limitation. It is as though we had a tunnel gauge, and you passed the load through the tunnel gauge. If the load is too small, or smaller than may go through, we don\u27t expand it, but if it does not pass through the gauge we must bring it down. If the adjustments were not provided for, it is obvious to all of us that what appears on the books of the carriers under the accounting rules of the Commission would determine what is the railway operating income. When the adjustment is put through this tunnel gauge these accounts must pass, and therefore we can not allow and we can not consider, or we should not attempt to think of adjustments or settlements of the guaranty except in relation to the books of the carrier. The adjustment is made of the accounts as they stand upon the books of the carrier. The settlement is made upon those accounts with the limitations which Congress has prescribed. If the limitations had not been prescribed those accounts would stand as written. With the limitations which Congress has prescribed, they stand as the maximum, and there is another maximum prescribed, which is this tunnel gauge of adjustment

Cost of maintenance and depreciation of cotton mills

In cotton mill accounting, as in practically all accounting which has to do with manufacturing processes, the division of the bookkeeping most difficult to handle successfully is that pertaining to maintenance. This term being used in its broadest sense as covering all costs of wear and tear of plant, including buildings, machinery, tools, etc. Maintenance, rightfully used in this broad sense, includes repairs, renewals, reconstruction, deterioration (or deferred maintenance) and obsolescence. We will, in this paper, view it under three primary aspects

Bringing Space Science Down to Earth for Preservice Elementary Teachers

This article reports on a collaborative enterprise between Oklahoma State University’s (OSU) NASA Education Projects and OSU’s College of Education preservice elementary teachers (PSTs) to engage approximately 400 middle school students for a 20-minute live downlink with Commander Kevin Ford from the International Space Station (ISS). NASA supports this opportunity through a competitive proposal process (National Aeronautics and Space Administration, 2014). The project’s theme, Pioneers in Space: STEM Careers on the Space Frontier, engaged both PSTs and middle school students in discussing the benefits of space research, while drawing on themes relevant to students’ regional history. PSTs prepared Pioneers in Space instructional units and led classroom activities linking 6th grade state science standards. The desired outcome was to promote a greater understanding of how space exploration benefits society and contributes to STEM innovations. This paper reports on how curriculum design and leadership experiences in space education and outreach impacted the PST participants

Ultrasonic inspection and self-healing of Ge and 3C-SiC semiconductor membranes

Knowledge of the mechanical properties and stability of thin film structures is important for device operation. Potential failures related to crack initiation and growth must be identified early, to enable healing through e.g. annealing. Here, three square suspended membranes, formed from a thin layer of cubic silicon carbide (3C-SiC) or germanium (Ge) on a silicon substrate, were characterised by their response to ultrasonic excitation. The resonant frequencies and mode shapes were measured during thermal cycling over a temperature range of 20--100~$^\circ$C. The influence of temperature on the stress was explored by comparison with predictions from a model of thermal expansion of the combined membrane and substrate. For an ideal, non-cracked sample the stress and Q-factor behaved as predicted. In contrast, for a 3C-SiC and a Ge membrane that had undergone vibration and thermal cycling to simulate extended use, measurements of the stress and Q-factor showed the presence of damage, with the 3C-SiC membrane subsequently breaking. However, the damaged Ge sample showed an improvement to the resonant behaviour on subsequent heating. Scanning electron microscopy showed that this was due to a self-healing of sub-micrometer cracks, caused by expansion of the germanium layer to form bridges over the cracked regions, with the effect also observable in the ultrasonic inspection

Identification of the promoter of amidase gene for expression of useful mycobacterial genes

The genetics of mycobacteria has lagged behind because of several reasons. Mycobacteria grow very slowly. their generation time ranging anywhere between 12-24 hrs. Mycobacteria are rather hydrophobic and tend to grow in clusters and there is difficulty in purifying individual cells for genetic analysis. Very few genetic markers have been found in mycobacteria because there is no known naturally occurring genetic exchange in mycobacteria. With the creation of genomic libraries of M. tuberculosis more than 50 genes have been characterised. Many of them are not expressed efficiently in Escherichia coli (E.coli) under the control of their own promoters, since very few mycobacterial promoters are recognised by the E. coli transcription machinery. This clearly shows that mycobacteria use a different system of gene regulation. Understanding the gene regulation of mycobacteria might throw light on the slow growth rate, about their persistence in a resting phase and also about their intracellular survival. Besides this if inducible or strong promoters are identified they can be used in over expression of genes coding for proteins useful in diagnosis and protection

Non-HLA gene polymorphism in pulmonary tuberculosis

BCG vaccination has been shown to give protection against tuberculosis. However, South Indian (Chingleput) Trial of BCG vaccination did not give any protection against bacillary forms of tuberculosis. A number of hypotheses and possibilities were put forward for this failure (1). One of the possibilities suggested was the genetics of the people (Host genetics) living in that region. Pulmonary tuberculosis is a granulomatous lung disease caused by Mycobactrium tuberculosis. Susceptibility to tuberculosis has been suggested to be multifactorial. Though environmental and socio-economic factors are primarily related, numerous studies have emphasised the importance of host resistance and hereditary susceptibility (2,3)

Determination of Arsenic, Mercury and Barium in herbarium mount paper using dynamic ultrasound-assisted extraction prior to atomic fluorescence and absorption spectrometry

A dynamic ultrasound-assisted extraction method using Atomic Absorption and Atomic Flourescence spectrometers as detectors was developed to analyse mercury, arsenic and barium from herbarium mount paper originating from the herbarium collection of the National Museum of Wales. The variables influencing extraction were optimised by a multivariate approach. The optimal conditions were found to be 1% HNO3 extractant solution used at a flow rate of 1 mL min-1. The duty cycle and amplitude of the ultrasonic probe was found to be 50% in both cases with an ultrasound power of 400 W. The optimal distance between the probe and the top face of the extraction chamber was found to be 0 cm. Under these conditions the time required for complete extraction of the three analytes was 25 min. Cold vapour and hydride generation coupled to atomic fluorescence spectrometry was utilized to determine mercury and arsenic, respectively. The chemical and instrumental conditions were optimized to provide detection limits of 0.01ng g-1 and 1.25 ng g-1 for mercury and arsenic, respectively. Barium was determined by graphite-furnace atomic absorption spectrometry, with a detection limit of 25 ng g-1. By using 0.5 g of sample, the concentrations of the target analytes varied for the different types of paper and ranged between 0.4–2.55 µg g-1 for Ba, 0.035–10.47 µg g-1 for As and 0.0046–2.37 µg g-1 for Hg