Search results
Results from the WOW.Com Content Network
The specimen is placed in a gel-like embedding medium, usually OCT which consists of polyethylene glycol and polyvinyl alcohol; this compound is known by many names and when frozen has the same density as frozen tissue. At this temperature, most tissues become rock-hard. Usually a lower temperature is required for fat or lipid rich tissue.
Damage from freezing cold injury occurs through direct freezing of tissue, disrupted blood flow to affected skin, and rewarming injury. [8] [11] [3] Freezing causes ice crystal formation in tissue that disrupts cell membranes and surrounding blood vessels. [11]
Similar to the frozen section procedure employed in medicine, cryosectioning is a method to rapidly freeze, cut, and mount sections of tissue for histology. The tissue is usually sectioned on a cryostat or freezing microtome. [12] The frozen sections are mounted on a glass slide and may be stained to enhance the contrast between different tissues.
The Eulerian specification of the flow field is a way of looking at fluid motion that focuses on specific locations in the space through which the fluid flows as time passes. [ 1 ] [ 2 ] This can be visualized by sitting on the bank of a river and watching the water pass the fixed location.
Controlled-rate and slow freezing, also known as slow programmable freezing (SPF), [18] is a technique where cells are cooled to around -196 °C over the course of several hours. Slow programmable freezing was developed during the early 1970s, and eventually resulted in the first human frozen embryo birth in 1984. Since then, machines that ...
Additionally, the shelf-fluid system works to provide specific temperatures to the shelves during drying by pumping a fluid (usually silicone oil) at low pressure. The downside to this type of freeze dryer is that the heat is only transferred from the heating element to the side of the sample immediately touching the heater.
Nitrogen is a liquid under −195.8 °C (77.3 K).. In physics, cryogenics is the production and behaviour of materials at very low temperatures.. The 13th International Institute of Refrigeration's (IIR) International Congress of Refrigeration (held in Washington DC in 1971) endorsed a universal definition of "cryogenics" and "cryogenic" by accepting a threshold of 120 K (−153 °C) to ...
A non-cartographic flow map showing the relative percentages of cardiac output delivered to major organ systems. Beside the flow maps in cartography there are several other methods for visualizing non-geographic flow: Baker flow map of fluid flows; Blood flow maps, see history of neuroimaging; Flow map or solution operator, see random dynamical ...