PubMed Health⌕ Search

Biomedical subjects

B Janzon

Publications and source records attributed to B Janzon.

At least 19 recordsLinked to original sources
PubMed1988

Terminal behaviour of deforming bullets.

Some types of deforming bullets, including soft-point hunting ammunition and so-called shotgun slugs, were fired against blocks of soft soap and against the muscular parts of the hind legs of live, anesthetised pigs. The deformation, breakup, and retardation of the bullets within the targets were recorded by means of a multi-flash X-ray setup. The extent of the soft-tissue damage was evaluated by means of debridement performed by a highly skilled surgeon. The excised tissue was then accurately weighed. The potential to transfer energy of these bullets was, as could be anticipated, extremely high, and the injuries caused were very large. The relations between bullet velocity, construction, deformation, breakup, and the resulting injuries are discussed.

Animals↗
PubMed1988

Wound ballistics of Swedish 5.56-mm assault rifle AK 5.

The recently adopted Swedish standard 5.56-mm assault rifle Ak 5, with ammunition 5.56-mm sk ptr 5 stkprj, closely similar to the Belgian weapon FNC, with corresponding ammunition SS 109, was fired against blocks of soft soap and against the muscular parts of the hind legs of live, anesthetised pigs. The behaviour and retardation of the bullets within the targets were recorded by means of a stereo, multiflash X-ray setup. The extent of the soft-tissue damage was evaluated in sections by means of debridement performed by a highly skilled surgeon. The excised tissue was then accurately weighed. The energy transfer characteristics and the wounding potential of the weapon are discussed.

Animals↗
PubMed1988

Some observations relating to behind-body armour blunt trauma effects caused by ballistic impact.

Live, anesthetised pigs were used to assess behind-armour blunt trauma effects. The thoraco-abdominal body region was covered with varying thicknesses of Kevlar fabric packets. This soft body armour was applied, either in direct contact with the thoracic wall of the animals, or with different plastic foam sheets, so-called trauma packs, between the armour and the skin. The live animals were surgically evaluated, and then sacrificed. Blocks of soft soap were subjected to equal tests and the behind-armour indentations were measured. The results indicate that serious injury to the body armour-protected chest may be caused by the impact of nonpenetrating bullets and shotgun pellets. Severe pulmonary contusions and lacerations were found when the energy transferred through the body armour was estimated to be high.

Abdominal Injuries↗
PubMed1985

Muscle devitalization in high-energy missile wounds, and its dependence on energy transfer.

Relations between the energy transferred by a high-velocity missile along a wound channel and the ensuing tissue destruction were studied in 25 live, anesthetized pigs. They were wounded in the muscular parts of the hind legs by an assault rifle bullet or by a spherical steel ball at about 1,000 m/s. The penetration of the assault rifle bullets was recorded by a stereo, multichannel flash X-ray arrangement. The energy transfer in the wound was evaluated from the X-rays. The wounds were surgically debrided in sections by a skilled surgeon. The energy transfer of the spherical steel bullets was measured. These animals had the thigh surrounded with a plaster of Paris cast, in order to suppress, as far as possible, the formation of the temporary cavity. The wounds were debrided. The amounts of tissue debrided were weighed and utilized as a measure of the extent of the injury. Good and consistent correlations between energy transfer and tissue debridement were obtained for the wound types studied. The amount of tissue debrided diminished by about 40% for the plaster-covered animals. Influence of boundary effects could be studied, and the results give indications of the mechanisms of missile wounding.

Animals↗
PubMed1982

Edge, size and temperature effects in soft soap block simulant targets used for wound ballistic studies.

In order to investigate the influence of various parameters on the outcome of wound ballistic tests using soft soap tissue simulant targets, an experiment study was performed. 6 mm spherical steel-balls were fired from a 6 mm smooth-bore rifle, giving a maximum velocity of about 1500 m/s. Such factors as the geometry of the target (square or cylindrical), location of the hit (eccentricity), size, temperature (0-20 degrees C) and method of evaluation were varied in a systematical manner. The results of the study indicate the accuracy to be expected in performing such tests, the limits within which variation may be allowed to ensure valid results. Finally a model for calculating the retardation force on the projectile as a function of penetration depth (energy transfer characteristics) from measurements of the diameter of the permanent cavity in the block is described, with block size and temperature as parameters. It must be emphasized that the results are valid only for the specific material studied. The results, however, make it likely that there exists a relatively simple method of calibration that can be applied to determine the specific values of parameters for other similar materials.

Biophysical Phenomena↗
PubMed1982

A proposed standard methodology for estimating the wounding capacity of small calibre projectiles or other missiles.

A standard methodology for estimating the energy transfer characteristics of small calibre bullets and other fast missiles is proposed, consisting of firings against targets made of soft soap. The target is evaluated by measuring the size of the permanent cavity remaining in it after the shot. The method is very simple to use and does not require access to any sophisticated measuring equipment. It can be applied under all circumstances, even under field conditions. Adequate methods of calibration to ensure good accuracy are suggested. The precision and limitations of the method are discussed.

Biophysical Phenomena↗
PubMed1982

Soft soap as a tissue simulant medium for wound ballistic studies investigated by comparative firings with assault rifles Ak 4 and M16A1 into live, anesthetized animals.

For the purpose of comparing the properties of a particular soft soap with those of live muscle tissue, a comparative study was carried out, involving firings into live, anesthetized pigs and into blocks of soft soap. The weapon - ammunition combinations utilized were Ak 4 - sk ptr 10 prj - the Swedish version of 7.62 mm NATO assault rifle M16A1- M. 193 - the U.S. standard weapon, calibre 5.56 mm. The registrations were done by flash X-ray units of 105 and 150 kilovolts, mounted in an orthogonal stereo set-up with 8-11 units, making it possible to obtain 4 to 6 measurements of bullet position, yaw angle etc. during the penetration of the target in one shot. By evaluation of these firings, and by "pooling" of the data for each series it was possible to calculate retardation force on the bullet as a function of penetration depth for the soap targets, and for the live targets. The results show that no significant difference can be discerned between the soft soap and animal tissue as regards their influence on the behaviour of the bullet.

Animals↗
PubMed1981

Optical properties of damaged and undamaged muscle tissue studied in high-energy missile wounds.

Modern surgical treatment of wounds caused by high-energy traumata includes the excision of all non-viable muscle tissue. To judge the transition zone between viable and non-viable tissue correctly, however, it takes a highly qualified surgeon, experienced in high-energy trauma surgery. Less skilled surgeons are tending to leave some non-viable tissue behind in the wound, which often leads to infection and re-operation and causes, among other things, extended suffering and hospitalization for the patient. Among the visible and palpable properties serving as criteria for the surgeon is that the non-viable tissue is dark purple, whereas the viable tissue is of lighter red colours. The perception of colour is depending on the optical properties of a surface and on the composition of the light illuminating it. A pilot study has shown that the colour contrast between viable and non-viable muscle tissue can be enhanced by using colour filters. In this investigation optical properties for muscle tissue in different degrees of viability have been scrutinized. It seems to be possible to find a clinically applicable method to help the surgeon in his work.

Animals↗
PubMed1979

The extent of muscle tissue damage following missile trauma one, six and twelve hours after the infliction of trauma, studied by the current method of debridement.

Spherical missiles with velocities around 1000 m/s were used to inflict missile trauma to one thigh of pigs. The determination of the impact and exit velocities made it possible to calculate the extent of energy transferred to the tissue. About one third of the pigs were treated surgically within one hour after the trauma, one third after a delay of 6 hours and one third after 12 hours. The surgical procedure consisted of debriding muscle tissue which showed impaired contractility and/or consistency and discoloration and/or lack of capillary bleeding - the current criteria of non-viability. The amount of debrided muscle tissue from each wound was weighed and the amount of debrided muscle tissue per joule transferred to the tissue was calculated. As compared to operations performed within one hour the average of the debrided muscle tissue per joule was greater after 6 hours delay and even still greater after 12 hours. However, the difference between the averages after 6 and 12 hours were not statistically significant.

Animals↗
PubMed1979

Break-up behaviour of some small calibre projectiles when penetrating a dense medium.

A study of the break-up patterns of two types of standard ball small calibre bullets fired from a range of 100 meters against targets made of soft soap was performed. A flash X-ray set-up was used to study the behaviour of the bullets while penetrating the soap. A simplified calculation of the stresses affecting the bullets was performed. It turns out that one predominant factor in the break-up process is the tumbling of the projectile. The longitudinal rotation velocity of the bullets is often so great that this is sufficient to cause-centrifugal stresses of high enough magnitude to cause rupture of the bullet lead core. This in combination with the high retardation forces acting on a bullet penetrating a dense medium at large angles of yaw is sufficient to cause an almost inevitable break-up for fast-tumbling bullets.

Biophysical Phenomena↗
PubMed1978

The extent of tissue damage in missile wounds one and six hours after the infliction of trauma studied by the current method of debridement.

Spherical missiles with velocities around 1000 m/s were used to inflict simultaneously missile trauma to both thighs of pigs. The determination of the impact and exit velocity enabled the extent of energy transferred to the tissues to be calculated. One thigh of each pig was treated surgically within one hour and the other one after a delay of 6 hours after trauma. The surgical procedure consisted of debriding muscle tissue which showed impaired contractility, consistency, discoloration or lack of capillary bleeding--current criteria of non-viability. The amount of debrided muscle tissue at the first operation showed a linear regression versus the extent of energy transfer, whereas after 6 hours no relation could be found between the amount of debrided tissue and energy transfer. There was no significant difference between the amount of debrided tissue per joule of transferred energy when the results of the two operations on each pig were compared.

Animals↗