Background: Research into middle ear mechanics and the evaluation of active middle ear implants are generally performed on fresh human temporal bone specimens. A drawback of this method is the limited period during which the specimen can be used before tissue decay begins. Tissue conservation that preserves mechanical properties is desirable.
Methods: Using laser Doppler vibrometry, the movement of the tympanic membrane, stapes, and round window were measured in 23 ears from 15 human whole head specimens embalmed according to Thiel. The ears were acoustically stimulated through the intact external auditory canal. The measurement results
were compared with data from the literature.
Results: The results were similar to those measured in living subjects and from fresh temporal bones, after excluding measurements with nontypical shapes see more or low amplitudes, that is, 9% for tympanic membrane, 38% for stapes, and 67% for round window. The best agreement was found for the tympanic membrane (mean difference between 0 and 5.2 dB) and for the stapes measurements (mean difference between 0 and 7.4
dB). Larger differences were found for the round window measurements (mean difference between 3 and 19 dB). For the stimulation levels used, the Thiel specimens behaved linearly in amplitude. The results remained reproducible for more than 20 hours in ambient air, and when the specimen was put back into Thiel solution, the measurements were stable for up to several months between measurements.
Conclusion: Our results showed that the middle BKM120 in vitro ears of Thiel-embalmed human whole head specimens can be used to study human middle ear mechanics; however, significant differences in some frequencies, particularly at the round window, have to be considered.”
“Palm kernel oil can be fractionated into stearin and olein fractions. Traditionally, industrial players only fractionate the softer
stearin fraction and harden it through complete hydrogenation. One stage dry fractionation yielded 37% of softer or 24% of harder stearin fraction. check details Two stages dry fractionation yielded 24% harder and 11% softer stearin fractions. Even though two stages dry fractionation salvaged up to 14% of the softer stearin fraction from the normally discounted palm kernel olein fraction, the double fractionation process was not always commercially feasible. Deciphering actual price statistics revealed that on a per metric tonne basis, the refining premium ranged from MYR90 to 250. Palm kernel olein discount was as high as 9% but could command premium over crude PKO by up to 2.5%. Due to the intrinsic relationship, the corresponding palm kernel stearin breakeven value could range from discount of MYR90 to premium of MYR1260 over crude PKO. The actual 60 months average market premium for palm kernel stearin stood at MYR870, promising an average MYR430 returns to refiners and processors. By incorporating two stages dry fractionation when the PKL discount was greater than 2.