One of the common questions we get from our customers is, “Which chip do I use to test my fluid?” RheoSense has a variety of different chips and you may wonder which chip would be the best for your application. The m-VROC® has four different designations of chips: A, B, C, and E. These letter values reference the max pressure capability of the MEMS pressure sensors inside the microfluidic flow cell. With the A-series being able to measure the lowest pressures for low viscosity fluids, the E-series are able to measure the highest pressures for higher viscosities and higher shear rates.
We frequently get the question, "how do I know that my equipment is working, or that these tests are accurate?" The best way to determine this and be sure of your results is to run a system suitability test.
A couple weeks ago, our technical specialists Rick Paulino and Gordon Stack measured different brands and types of olive oil. The two technical specialists tested to see if there was a difference between 100% pure olive oil compared to olive oil that has been blended with 10% canola oils. Their study concluded there was a ~10 cP difference between the oils, with olive oil boasting a higher viscous characteristic.
We've heard your requests and are ecstatic to announce the launch of our newly crafted program that guarantees end-users complete data analysis versatility (and much more)...: RheoSense Clariti.
We are all familiar with maintaining our lab instruments, but how often do we perform maintenance on our lab methods or SOPs?
In the upcoming weeks, we are proud to announce the release of our latest application note regarding concentration dependence in protein viscosity. In this app note, Dr. Stacey Elliott gathered viscosity data for Bovine Gamma Globulin (BgG) formulations over the full concentration range, including therapeutic levels ≥ 100 mg/mL, using the VROC®Initium. The solution buffer included sucrose which is a common additive to enhance stabilization during freeze-drying and storage. Relative viscosity versus concentration curves were fit with the Ross-Minton equation which is a frequently used analysis tool for protein formulations.
To view application note, click below!
According to Cell Press, "Royal jelly is produced in [two different] glands of worker bees, one that produces the protein in a neutral pH and one that produces fatty acids that can reduce said pH when the two secretions" come together (Cell Press).
For a honeybee, royal jelly is a crucial diet for the first couple days for all bees. And for honeybee larvae to become queen, the larvae must be fed and be surrounded by royal jelly for it to morph successfully. However, because queen larvae, "are too big to fit into the cells of the hive's honeycomb," they are able to hang upside down in the queen's cell anchored with the royal jelly (Cell Press). So, what allows this royal jelly to acquire these properties?
Turns out, royal jelly is not always thick and sticky. In a recent study, researchers proposed that the viscosity of a royal jelly were dependent the particle size of a protein found in royal jelly (known as royalactin, or MRJP1) was directly correlated to the pH level found inside. The study conveyed that there was a noticeable size difference within the MRJP1 jelly when exposed to a purifier at pH 4 and at neutral (pH 7). For instance, "Most purification protocols are standardized at pH 7, [which yielded] a strange, runny consistency [within the jelly]" whereas when maintained between pH 4 and pH 5, the viscosity of the jelly seemed gelatinous and almost adherent (Cell Press). The precise pH affects the overall viscosity of royal jelly, which is an essential component in providing the optimal environment for the queen bee to develop in her early stages. If the pH levels were outside 4~5, the royal jelly would lose its heavy, sticky properties and would not be able to hold the queen larvae.
Measuring viscosity dates back to as early as the 19th century. French physicist Jean Poiseuille discovered the concept of measuring viscosity by formulating the "mathematical expression for the flow rate for the laminar flow of fluids in circular tubes." Later on, this formulation was discovered by a German hydraulic engineer Gotthilf Hagen, which came to be known as the Hagen-Poiseuille equation (Britannica). Early measurements of viscosity focused primarily on the flow of blood. Measurements were conducted using the hemodynamometer that incorporated narrow tubes & glass capillaries in effort to measure the pressures in the arteries of horses and dogs (Sutera).
As a lubricant begins to breakdown it undergoes significant viscosity changes. These viscosity changes can play a critical role in the life and performance of moving parts. For example, knowing when to change the engine oil in a car is straightforward, every 3,000 to 5,000 miles is a good rule of thumb. Going beyond the recommended scheduled oil change runs the risk of critical component failure leading to engine damage. However, what if you don’t have a convenient method, like miles driven, to gauge the health of your lubricant? How will you know when the lubricant begins to breakdown? The solution to this is knowing your viscosity!