Body growth, hematological profile, and clinical biochemistry of heifer calves sired by a bull or its clone.

The aim of this paper was to compare body growth, hematological profile development, and clinical biochemistry in the female progeny of a sire with the female progeny of its clone. Sixteen Friesian female calves, 9 daughters from a tested bull (BULL) and 7 from its somatic cell nuclear transfer clone (CLONE) were monitored from birth to 60 wk of life. Body weight (BW), wither height (WH), hip height (HH), body length (BL), and hearth girth (HG) were measured at birth and 4, 8, 12, 16, 20, 24, 36, and 50 wk. Blood samples were taken from jugular vein at 12 to 48 h from birth and 1, 2, 3, 4, 8, 12, 16, 20, 24, and 36 wks of age, to be analyzed for hematological, serum protein, and metabolic profiles. At the same time, rectal temperature (RT) was recorded. Age at puberty was assessed on surviving heifers by measuring weekly plasma progesterone levels. Data were evaluated using a mixed model, taking into account the repeated measures in time on the calf. For each variable, different covariance structures were tested, choosing the best according to the Akaike's Information Criteria. Significant was set at P < 0.05, and a trend was considered for P < 0.10. At 24 wk of age, WH was lower in CLONE daughters than BULL daughters. Around 20 wk of age, there was a trend for lower BW in CLONE daughters than BULL daughters, confirmed from differences in HG. There was no difference in RT due to sire effect. Blood glucose concentration decreased in both groups during the first 4 wk of life; at birth, only a trend for higher blood glucose in CLONE daughters was recorded, whereas an opposite trend was observed for plasma creatinine. Total leukocyte count did not differ between progenies. Circulating lymphocytes tended to be lower in CLONE than BULL daughters. The neutrophil: lymphocyte ratio tended to be higher in CLONE than BULL calves. No difference was demonstrated for erythrocyte features, whereas mean platelet volume tended to be lower in CLONE than BULL progeny. From these results, there were no differences between progenies from BULL and its clone that suggest welfare problems in the first 6 mo of life.

Proton and iron ion observations from a solid-state microdosimeter.

The tissue equivalent proportional counter (TEPC) that utilises a gas cavity has been the standard to obtain microdosimetric observations. An alternative is the solid-state microdosimeter that replaces the gas with a solid-state detector with microscopic sensitive volumes. Here, we describe the development of two versions of a personal solid-state microdosimeter for space exploration applications and give test results for iron and proton beams with comparisons to TEPC measurements and Geant4 radiation transport code simulations. In addition, we describe and provide test results of an optical technique to carry out an end-to-end system test and calibration of a silicon solid-state microdosimeter. This technique eliminates the need for an ionising radiation source with its attendant issues on use and transportation and provides an advantage over the TEPC.

Microdosemeter instrument (MIDN) for assessing risk in space.

Radiation in space generally produces higher dose rates than that on the Earth's surface, and contributions from primary galactic and solar events increase with altitude within the magnetosphere. Presently, no personnel monitor is available to astronauts for real-time monitoring of dose, radiation quality and regulatory risk. This group is developing a prototypic instrument for use in an unknown, time-varying radiation field. This microdosemeter-dosemeter nucleon instrument is for use in a spacesuit, spacecraft, remote rover and other applications. It provides absorbed dose, dose rate and dose equivalent in real time so that action can be taken to reduce exposure. Such a system has applications in health physics, anti-terrorism and radiation-hardening of electronics as well. The space system is described and results of ground-based studies are presented and compared with predictions of transport codes. An early prototype in 2007 was successfully launched, the only solid-state microdosemeter to have flown in space.

End-to-end system test for solid-state microdosemeters.

The gold standard in microdosemeters has been the tissue equivalent proportional counter (TEPC) that utilises a gas cavity. An alternative is the solid-state microdosemeter that replaces the gas with a condensed phase (silicon) detector with microscopic sensitive volumes. Calibrations of gas and solid-state microdosemeters are generally carried out using radiation sources built into the detector that impose restrictions on their handling, transportation and licensing in accordance with the regulations from international, national and local nuclear regulatory bodies. Here a novel method is presented for carrying out a calibration and end-to-end system test of a microdosemeter using low-energy photons as the initiating energy source, thus obviating the need for a regulated ionising radiation source. This technique may be utilised to calibrate both a solid-state microdosemeter and, with modification, a TEPC with the higher average ionisation energy of a gas.

MIDN: a spacecraft microdosimeter mission.

MIDN (MIcroDosimetry iNstrument) is a payload on the MidSTAR-I spacecraft (Midshipman Space Technology Applications Research) under development at the United States Naval Academy. MIDN is a solid-state system being designed and constructed to measure microdosimetric spectra to determine radiation quality factors for space environments. Radiation is a critical threat to the health of astronauts and to the success of missions in low-Earth orbit and space exploration. The system will consist of three separate sensors, one external to the spacecraft, one internal and one embedded in polyethylene. Design goals are mass <3 kg and power <2 W. The MidSTAR-I mission in 2006 will provide an opportunity to evaluate a preliminary version of this system. Its low power and mass makes it useful for the International Space Station and manned and unmanned interplanetary missions as a real-time system to assess and alert astronauts to enhanced radiation environments.

Advances in space technology: the NSBRI Technology Development Team.

As evidenced from Mir and other long-duration space missions, the space environment can cause significant alterations in the human physiology that could prove dangerous for astronauts. The NASA programme to develop countermeasures for these deleterious human health effects is being carried out by the National Space Biomedical Research Institute (NSBRI). The NSBRI has 12 research teams, ten of which are primarily physiology based, one addresses on-board medical care, and the twelfth focuses on technology development in support of the other research teams. This Technology Development (TD) Team initially supported four instrumentation developments: (1) an advanced, multiple projection, dual energy X ray absorptiometry (AMPDXA) scanning system: (2) a portable neutron spectrometer; (3) a miniature time-of-flight mass spectrometer: and (4) a cardiovascular identification system. Technical highlights of the original projects are presented along with an introduction to the five new TD Team projects being funded by the NSBRI.

Precision bone and muscle loss measurements by advanced, multiple projection DEXA (AMPDXA) techniques for spaceflight applications.

An advanced, multiple projection, dual energy x-ray absorptiometry (AMPDXA) scanner system is under development. The AMPDXA is designed to make precision bone and muscle loss measurements necessary to determine the deleterious effects of microgravity on astronauts as well as develop countermeasures to stem their bone and muscle loss. To date, a full size test system has been developed to verify principles and the results of computer simulations. Results indicate that accurate predictions of bone mechanical properties can be determined from as few as three projections, while more projections are needed for a complete, three-dimensional reconstruction.