In the present study, we treated the cartilages with collagenase prior to the extraction of total RNA, because it is difficult to extract the total RNA from hard and ECM-rich tissues such as bone and cartilage [ 8, 34, 35].
Because it is difficult to extract and replace a worn-out or defective artificial hip, doctors routinely advise patients to put off hip replacement as long as possible.
Although total reserves (proven, probable and possible) amount to 42bn barrels, 83% of total reserves are located in regions where it is difficult to extract the oil.
An additional problem is that when everything tumbles into a giant heap it is difficult to extract material for recycling, now an important way of defraying demolition costs.Apart from dust, explosive charges can throw out fragments called "flyrock".
Petroleum Development Oman is also using polymer flooding in its Marmul field, identified from its discovery in 1956 as an area with heavy oil that is difficult to extract using traditional methods.
It is difficult to extract any general principles of biological design from among life's messy details or to distinguish what is fundamental to life as a general phenomenon from what is merely an accident of how life evolved on Earth.
Second: I have always thought that it is difficult to extract from my books, each of which is so different from the others, a unitary discourse, an overall definition, maybe even just the outline of an author that is not also split up.
At high temperature, it is difficult to extract the inserted lithium.
It is difficult to extract quantitative information of pore space from thin section.
DNA of Begonia species is difficult to extract, especially for those collected from limestone substrates.
However, this feature is difficult to extract due to the strong return from the truck geometry.
