Mastication - Science topic

Dear Dr. Pablo Orosa ,

This topic is extremely broad but also critical for the macroscopic behaviour of asphalt. Professors Yiqiu Tan and Meng Guo have a high-quality set of articles on the bitumen–filler interaction including the theoretical background. You might also find the following one useful (especially see the discussion section): .

Of course, it is extremely meaningful to talk about the optimisation of mastic composition, and thus the optimum content of filler (whereby for various reasons of interpretation and comparability, it is the best to express it as volume fraction).

On the one hand, by increasing the filler content in the domain of low contents, mastic becomes stiffer and consequentially more resistant to permanent deformation at high temperatures. On the other hand, by increasing it in the domain of high contents (as you mentioned about e.g. 40 % or more), the bitumen film becomes thinner and thinner with increased particle-to-particle contact, which ultimately makes it much less resistant to fatigue (or analogous damage effects) at intermediate temperatures. While permanent deformation in mastic can, to a certain extent, be compensate by its volume fraction and the coarse aggregate skeleton, poor fatigue resistance caused by mastic cannot and is therefore much more dangerous. You should also think about the ability of filler (though depending on its mineralogy, porosity, and specific surface) to absorb less polar fractions from bitumen and reduce its ductility further impairing the fatigue behaviour (similar to the effect of ageing). Finally, the stress relaxation ability at low temperatures should not be forgotten and is also highly dependent on the above-mentioned mastic composition.

Nevertheless, the behaviour of mastic (as only a single phase in the hierarchically organised asphalt system) is not related to the overall behaviour of in-service pavement layer as directly as bulk asphalt specimens. Therefore, it is harder to establish robust and unified criteria for optimising its composition.

I would suggest the work of Paulo Freire in Brazil and latinamerica. Perhaps this approach to education is what you are looking for. "The education as the practice of freedom" is one my favorites books written by him. He worked in many countries sharing a different approach to education than can be useful to empower students and to make them more commited with their social and political reality. Here you have a link.

Dear K L A V Harnadh

These links might be an asset, have a look:

1. https://www.mathworks.com/matlabcentral/fileexchange/54555-linear-viscoelastic-design-optimization

2. https://www.mathworks.com/matlabcentral/fileexchange/68710-dma2prony_opt

Kind Regards

Hi, everything is right, you just confuse a little bit. The contact angle is the angle between the cement matrix surface and water/air border (see https://en.wikipedia.org/wiki/Contact_angle#/media/File:Contact_angle.svg). That is why, the larger the contact angle is - the more hydrophobic material is and vice versa. In your case, if the angle is small it means that the material is hydrophilic. The contact angle depends on different parameters like the composition of the cement mastic or roughness (it can be because of the surface irregularities). In general, cement-based materials are porous (7% in the case of ordinary concretes) so, even if they are not hygroscopic, they absorb some quantity of water.

The use of fetal bovine serum in cell culture is to provide growth factors that support the cells' ability to grow and divide. These proteins must be in their native conformation in order to interact with receptors on the surface of the cells and have their effect.

The problem with using a microwave oven to warm the medium before use is that it does not heat the solution evenly, resulting in hot spots at which protein denaturation can occur. The medium also contains a lot of bovine serum albumin, which could coagulate if overheated.

People don't normally consume uncooked fetal bovine serum, so we are not exposed, even briefly, to the growth factors in it. Even if people did do that, the exposure would be so brief before the proteins were destroyed in the digestive tract, that it is unlikely that they would have any effect.

For human cells in culture, it is likely that human growth factors would be more effective than bovine ones, but fetal bovine serum is readily available. If desired, cell cultures can be transitioned from fetal bovine serum to serum-free medium, which contains purified growth factors. I'm not sure whether such media can be obtained with specifically human growth factors.

I feel the selection of material model is very important in your problem, which model did you use in simulating your problem..i recommend you to use soft soil or cam clay model to predict your problem..all the best..

I agree with dr Mohammed Nasser Alhajj that "Occlusal Vertical Dimension" depends on the occlusal surfaces of the teeth, and since edentulous patients have no teeth so there is no definite occlusal stop, and in that case, vertical dimension of occlusion can only be assumed by variable methods, most commonly, subtracting (2-4 mm) freeway space from RVD.

However, I think dr Faheemuddin Muhammad is assuming that if the vertical dimension of edentulous patients can be measured with the jaws closed, then the difference between estimated VDO and the vertical dimension with jaws closed can give an idea about the available inter-ridge space to detect suitability of the planned prosthesis.

For me in my research work, I use tentative jaw relation to detect suitability of available inter-arch space with the planned prosthesis, however your idea dr Faheemuddin Muhammad can be a good research point that may discover a new technique that would save clinicians effort and time.

Good Luck in that !

Best wishes.

I can recomend you to read about oral cryotherapy during infusion of chemotherapy. Oral cryotherapy is one of the recomended preventive treatment in guidelines for oral mucositis by Suportive Care in Cancer and ASCO. My research on cryotherapy showed significant lower duration and grade of oral mucositis (WHO grading) om patinets receiving high dose chemotherapy in connection with stem cell transplantation.

Measuring bite force magnitude is fairly straightforward (different transducers are used in the citations below, and there are undoubtedly several other designs). Measuring force at the TMJ is much more difficult, because introduction of a transducer into the joint is going to be invasive and will certainly compromise the system in some way. Other options would be to use bite force data to infer joint force via a simple static analysis or a more sophisticated approach such as FEA. In either case, you will have to know the magnitude and direction of bite force. Even more challenging will be estimating the adductor resultant. There is not currently a reliable way to do this. So the best option would be to come up with a range of estimates for these values and see how TMJ force changes over different iterations.

Dechow PC, Carlson DS. (1983). A method of bite force measurement in primates. J Biomechanics, 16(10), 797-802.

Waltimo A, Könönen M. (1993), A novel bite force recorder and maximal isometric bite force values for healthy young adults. European Journal of Oral Sciences, 101: 171–175.

Ferrario V F, Sforza C, Serrao G, Dellavia C, Tartaglia GM (2004), Single tooth bite forces in healthy young adults. Journal of Oral Rehabilitation, 31: 18–22.