As we discussed in a previous post, liquid nitrogen is not only difficult to order online, but also has some unbelievably cool science behind it. We discussed how the cooling effect of liquid nitrogen is due to its very low boiling point (−196 °C), and for this reason it can quickly freeze human skin upon contact. This application is referred to in the scientific community as ‘cryotherapy’. The origin of the term comes from the Greek words for ‘cold’ and ‘cure’, and is essentially the use of low temperatures to help heal or cure certain conditions, such as removing benign lesions from the surface of the skin or preserving live tissue. As one can imagine, this means that cryotherapy likely has many applications, but today we will specifically discuss the use of liquid nitrogen sprayers in removing lesions and freezing tissue.
Cryosurgery is a type of cryotherapy that specifically applies to the delivery of liquid nitrogen to living or benign tissue via a liquid nitrogen sprayer in order to freeze and destroy the tissue. Often, cryosurgery is used for small cosmetic growths, such as skin tags, warts, moles, and more seriously, skin cancers. By rapidly cooling the tissue, the liquid nitrogen actually freezes the cytosol of the cells, causing them to fracture and rupture internally. Think of the cytosol as the plush, cozy swimming pool that all of the cellular machinery responsible for maintaining our cells swims around in. This is mostly made of water, and when water freezes, it expands. That’s the same reason you make sure to drain external plumbing on the outside of your house before the winter—just like the pipes will crack if the water inside them freezes, so too do your cells if they are rapidly frozen. For this reason, liquid nitrogen sprayers see most of their use in external application.
However, liquid nitrogen cryosurgery can also be performed internally in the case of many cancers, such as liver, lung, and prostate. Liquid nitrogen has also seen internal application in the treatment of hemorrhoids, although this can be painful for the patient due to the fact that other local damage may occur. For this reason, liquid nitrogen sprayers are often preferred due to their high precision, ability to be manipulated, and dependability. Although cryosurgery is often painless, since damage to healthy surrounding tissue can sometimes occur it is not uncommon for doctors to provide a little bit of analgesia with most procedures, such as a Tylenol or Aleve.
When was the last time you had to roll up your sleeves, soap up a rag, and wash a nice sink-load of dirty dishes? I’m guessing last night, unless you’re a bachelor. In that case, it’s better if you don’t answer. Well, in the 1950s folks got pretty sick of washing dishes and laboratory equipment the same old way it had always been done. And no, I’m not referring to the advent of the automatic dishwasher. I’m referring to ultrasonic cleaners! Although they didn’t see home use until around the 1970s, ultrasonic cleaning was used extensively in industrial application after its discovery. Utilizing sound waves, the device emits variable, oscillating frequencies of ultrasonic waves into fluid within a container. By emitting the sound waves into liquid, they can travel throughout the container and disperse their energy to any particles submerged within. In the case of a dirty beaker, these sonic waves will bounce off of the beaker and the contaminants on top of it, effectively loosening and removing them in the process. This is thanks to a phenomenon known as ‘cavitation’, in which the ultrasonic waves exert pressure within the liquid and create bubbles, or voids, transferring their force onto any contaminants they come into contact with. Through this action, ultrasonic waves ‘clean’ the contents of the device.
Since sound waves bounce, or refract, off of surfaces, ultrasonic cleaners are perfect for applications requiring detailed and impeccable cleaning. Ideal materials that are easily cleaned ultrasonically include glass, aluminum, ceramic, and rubber. Essentially, most non-volatile solids are perfect candidates. Due to the fine, deep cleaning of ultrasonic waves, often they are used in laboratory environments requiring clean materials and contaminant-free tools. One such brand that sees widespread use in the medical field are Branson ultrasonic cleaners, which work the same way as the larger, industrial models. Much smaller, they usually are sized to fit on any standard lab bench and can either use tap water, deionized water, or specialized cleaning solutions as the liquid medium. However, as is important to remember, ultrasonic cleaners do not sterilize the instruments placed within—they only remove debris and contaminants, so sterilization is still a necessary step after ultrasonic cleaning.
Branson ultrasonic cleaners offer a slew of special features that were previously unavailable or prohibitively expensive, such as sweep frequency oscillation to prevent vibration from moving the machine around the lab bench and a number of fitted accessories that fit within the tank during cleaning. For different applications, different cleaning solutions may be more suitable.
Mixing two things together is pretty easy, right? Well, in most cases it is—the difficult part is separating the components out of a mixture. As dairy farmers of the 19th century discovered, there had to be a better way to quickly separate the cream from milk without having to wait for the cream to slowly rise to the top. This was not only time consuming, but it also risked having the entire batch of milk turn sour before the cream could be skimmed away. To solve this problem, the first and most primitive centrifuges were created. These early versions of the centrifuge were hand cranked and essentially spun a container around a central pivot point at high speeds, applying centrifugal force to the contents and causing them to separate based on density. This is called the principle of sedimentation. Thus, the denser material would end up on the bottom of the container and the lighter, less dense material would form a surface layer. In the case of milk, the much-desired and valuable cream would rise to the surface for collection.
However, as with most cutting edge technology, centrifuges quickly found use in a wide variety of vastly different applications. From laboratory use analyzing blood samples, to food production and quality control, to industrial chemical purification, and even drying clothes, centrifuges are a crucial piece of technology in the modern world. Arguably the most popular modern brand of medical-grade centrifuge, Unico centrifuges represent the pinnacle of the original design. Spinning their contents at 3400 to 4000 revolutions per minute (that is VERY fast), these multipurpose designs allow for a number of different applications from laboratory assay of blood cells to separation of cellular DNA and proteins. Due to their new-and-improved designs, many modern tabletop centrifuges also have much smaller footprints than their bulki
Unico centrifuges also feature variable speed settings for applications requiring the separation of liquids of varying densities and extremely quiet operation. They also feature automatically locking lids, digital readouts, and shock absorbing rubber feet to prevent noise and vibration from moving the unit while it is in operation. However, as with all centrifuge technology, they must be loaded evenly to avoid damage to the machine and the risk of personal harm. Also, much unlike the hand-cranked milk centrifuges of the past, one can now set a digital timer on the centrifuge, leave the room, and return 30 minutes later to a perfectly separated test tube.
If you’ve ever been to the doctor and had blood drawn, chances are they utilized a handy little device known as a diff counter to quickly estimate the proportions of different types of blood cells in your body. This proportion is very important because it often tells much about the health of the patient, especially if they have a compromised immune system making them vulnerable to opportunistic infection. By taking a sample of your blood and observing it in a diff counter, the health professional can physically count the number of each type of blood cell to extrapolate whether a particular type of blood cell is either low or high in the patient. This is called a ‘differential count’, the namesake of the device used to help estimate blood cell count. This is such a good indication of general health that blood tests are one of the most common laboratory tests performed to this day.
Basically, the body has three types of blood cells—erythrocytes (red blood cells), leukocytes (white blood cells), and platelets (the elements that help your blood clot when you are cut). If any one of these three pieces of our body’s puzzle is out of the normal range, chances are you may be at risk for infection, bleeding, drug toxicity, or a number of other serious medical problems. To help discover this early, your doctor may suggest having a full blood panel run, which involves calculating the patient’s blood count. As I mentioned earlier, this is where a diff counter would be employed. Then, after generating a rough percentage based on the blood sample that a phlebotomist would have already drawn, prepped, and sent off to the lab, this sample number would be extrapolated to generate a full blood count. This number would represent the absolute number of each type of blood cell within the patient’s body, and some devices can even recognize more specialized blood cells based on their shape!
To generate the differential count, there are both automated and manual methods of counting the blood sample. A diff counter can be either—LW Scientific's 10 Key Digital Diff Counter with LED display is new for 2013 and uses modern computerized technology for simple and accurate blood cell counts, alongside the older, manual LW Scientific 5 or 8 Key Differential Counter . The manual diff counter requires that the physician actually count each individual cell under a microscope, utilizing proportions to generate a rough total blood cell count, while the automated variety often do this on their own to a high degree of accuracy. As you can imagine, in the hectic, modern world, most laboratories prefer the automated, digital units for both their ease of use and accuracy.
As far back as the Egyptians (and probably much earlier), civilizations have always needed to compare quantities of goods when trading commodities. One of the earliest records of this surrounds the trade of salt. Specifically, ancient civilizations relied upon displacement of water to calculate volumes of salt being traded. By submerging the commodity in water, they could note exactly how far it caused the water level to rise. Next, once they had estimated the difference in the two water levels, they could approximate the volume of the commodity. However, if there is one thing we know about salt, it’s that it doesn’t handle being submerged in water very well. To circumvent this obvious issue, balances were invented. Although this technology did not initially allow for the calculation of an object’s absolute weight, it did allow for traders to compare the relative weight of two goods. Eventually, this evolved to the point where standard weights and measures could be placed on one side of the scale, to estimate absolute weight, and now to current-day technology that affords us extreme precision and accuracy when measuring weights via advances in digital technology.
Now that the technology behind the common scale has advanced so far, so have its uses. In any laboratory setting, there is one piece of equipment that is absolutely essential to everyday operation. Without a solid, reliable precision balance, no laboratory can operate effectively. Carefully calibrated, precision analytical balances allow for incredibly small amounts of material to be accurately measured to within 0.01 of a gram or less over and over again. The worldwide leader in precision balance technology is Ohaus, which has Ohaus distributors across the nation selling their brand of electronic scales. These come with a manufacturer’s warranty, customer support, and a stellar reputation spanning decades.
The benefits of using an electronic analytical balance over the older, mechanical balances are dazzling. To start with, analytical balances often have digital interfaces, removing human error and the need to interpret the scale’s readout. Additionally, many of the new models sold by Ohaus distributors are very quick and easy for professionals to calibrate, along with providing step-by-step walkthroughs explaining to the user how to balance and zero the device before taking a measurement. Many models also feature transparent windows that surround the scale, called draft guards, to prevent turbulence in the air from affecting the readout of the device. The final benefit of this new generation of analytical balances is that they have few moving parts, largely avoiding the danger of mechanical failure that conventional balances are prone to.