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General Thermography
Published in James Stewart Campbell, M. Nathaniel Mead, Human Medical Thermography, 2023
James Stewart Campbell, M. Nathaniel Mead
Sunburn involves a different damage mechanism, quite distinct from thermal burns. Thermal burns are caused by excess infrared (IR) exposure, which can penetrate deeply by conduction. Sunburn is caused by excess ultraviolet (UV) exposure, which does not penetrate the skin deeply or create much heat. UV exposure damages dermal cellular organelles and DNA, causing inflammation. Strong ultraviolet sources other than sunlight can also cause skin damage. Overexposure to a welding arc results in a type of UV burn that appears similar to sunburn, though the distribution over the skin is different. Like welder's burns, overexposure to UV reflecting off snow causes corneal photokeratitis (“snow blindness”) and can damage anatomy not usually affected by sunburn, such as the roof of the mouth or the interior of the nostrils.11
Geography
Published in Andrew M. Luks, Philip N. Ainslie, Justin S. Lawley, Robert C. Roach, Tatum S. Simonson, Ward, Milledge and West's High Altitude Medicine and Physiology, 2021
Andrew M. Luks, Philip N. Ainslie, Justin S. Lawley, Robert C. Roach, Tatum S. Simonson
In the high Himalayan valleys and Tibet, traditional clothing assemblies have had similar features. The main garment was a thick sheepskin “chupa” with long, wide sleeves that, when extended, keep the hands warm; gloves are never used. Normally the garment was gathered around the waist by a belt and hitched up to the knees so that there is a pocket for loose objects in front of the chest. When the belt was loosened, the garment extended to the ground and thus could be used as a sleeping robe; often in warm conditions one or both shoulders are left bare. Under this is a woolen shirt and often long woolen, cotton, or sheepskin trousers. Soft leather boots with decorative wool leggings extending to the knees were packed with grass, straw, or leaves, but a Tibetan often may walk in bare feet in the snow or through streams. Some wear a felt hat or balaclava and, to prevent snow blindness, yak hair would be put in front of the eyes if goggles were not available (Desideri 1712–27; Moorcroft and Trebeck 1841). Other traditional methods used by Tibetans included blackening the eyelids and wearing masks with tiny eye holes, the rims of which are blackened (MacDonald 1929). Cotton clothing is favored at high temperatures and low altitudes, but nomads wear wool or sheepskin. Many now wear wool sweaters and leather boots. Tibetan nomads sleep resting on their elbows and knees with all their clothes piled on their backs (Duff 1999; Holditch 1907). This “fetal position” diminishes surface area and therefore heat loss; contact with the ground is also minimal.
UV Reflectance Photography
Published in Adrian Davies, Digital Ultraviolet and Infrared Photography, 2017
UV radiation increases rapidly with altitude, and at a height of 5,000 metres there is 40 per cent more UV than at sea level. Snow and ice reflect up to 80 per cent of UV radiation, which is why skiers and mountaineers need to wear UV-protective goggles to prevent snow blindness.
Did hypervitaminosis A have a role in Mawson’s ill-fated Antarctic exploration?
Published in Clinical Toxicology, 2022
December is the midsummer season in Antarctica, however in the year 1912 events set in motion would claim two lives. December 14 would be remembered as a day of both triumph and tragedy. Exactly a year earlier in 1911 far across the continent a small celebration was taking place. Roald Amundsen and his Norwegian team had become the first to reach the South Pole [4]. Through strategic planning, Amundsen’s team survived the trip back from the pole, by planning ahead calculating when to consume their means of transportation and source of vitamins, their sled dogs, in order to survive [4]. However, on that same date, exactly a year later, on 14 December 1912 in Adelieland, the Mawson party had to deal with the first of several tragedies [5,6]. Ninnis stepped off his sledge onto an ice bridge crossing a deep crevasse and disappeared through the snow, along with the six strongest dogs [5,6]. Along with him plummeted the sledge that contained the bulk of the food supply, and the sturdier of the two tents they were carrying [5,6]. Previously they had lost six dogs as runaways, and now Ninnis and six more dogs were dead at the bottom of an inaccessibly deep crevasse [6]. They had one remaining sledge, six dogs weakened by the excruciating trip so far, only one week of food rations left, along with only a thin tent cover, cooking supplies, and a rifle [5]. Mawson and Mertz reassessed their situation, and they concluded that dogs would need to be consumed in order to survive. The first night after the accident they shot one of the dogs, butchered him, and fed some as food to the remaining dogs [5,6]. This was their first meal of dog liver, and the journal entry of Mawson notes, “It was a happy relief when the liver appeared…. it was easily chewed [5].” They recalculated their rations and decided to reduce what had been a planned 34 oz per day ration of food down to 8 oz per day [5]. They were 315 miles (507 km) from their base camp (Figure 2) [5]. Even though they marched 12 h a day, making 20 miles (32 km) on the first day, they only made 15 miles (24 km) per day on a good day [6]. Hunger, thirst, snow blindness, and exhaustion were their constant afflictions. The skin of their face, ears, and the soles of their feet peeled off in full thickness [5,6,8]. Mawson coated the raw surfaces of his denuded soles with lanolin and bandaged the desquamated dermis back onto his feet as a protection from deeper damage. They were able to treat their snow blindness with zinc sulphate and cocaine, which they still had [5].