One of very basic idea why we need to study biosensing is as follows. It is very crucial to routine determination of bacterial species inside foodstuff and water resource. Thus, methods are being developed. There various methods, one such classical methods is nucleic acid hybridization assay, but this method is time consuming. So, this is why biosensors are developed to produce such reversible, sensitive, reusable, reliable and simple enough to use. Read the rest of this entry »

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After being away for almost one month due to graduation of my degree and my tight schedule in my home institute, now I have been able to sit behind my laptop again to continue what I have discussed in previous post about finite dose of toxic chemical in this case, barium, Ba. In the last post, finite dose for barium part 1, I have given the example how to measure a simple problem. Fatal dose in known, blood volume is known as well, so we can measure the Ba concentration in the blood associated with the fatal effect.

What I am going to explain in this post is more complex than the previous one. I will give the case of Ba, if entering the body at a time and if Ba is trapped inside the salt, dissolve in the blood stream for a certain period, and how we can measure the concentration of Ba for acute effect and for a certain period of time. Read the rest of this entry »

After being busy with my theses now I am able to back to here again. Previous posts have explained the single time dose of a toxic chemical entering the ingestion tract. So this time, I would like to explain about the finite dose of barium that enters the body. As we know on the previous post, the single dose is described and the dose, and now the dose is continously enters the body or digestion organs. Read the rest of this entry »

This post relates to previous post about biotransfer factor in previous post. If you haven’t visited that post yet, I suggest you do so. I would like to provide an example on how to calculate the concentration of chemical A if not 100% is removed in the liver organ.

The keyproblem to this matter is whether BTF is dependent or independent for chemical removal in the liver or not. Depends or independent is determined by toxicology study. We can know only if the figure is confirmed as a linear function between concentration of chemical in the body with the dose as follows: Read the rest of this entry »

We have talked the principle idea of risk assessment. In this post, I would like to again remind, that no one in this entire planet is risk-free for health problem. That is because we are actually get exposed with so many toxic chemicals present ambient within our surrounding. The inside process on how these toxic chemicals enter the body and get absorbed by our digestive tract is explained by toxicology science. Risk assessment only try to predict the estimation of people get an observable effect. Read the rest of this entry »

Bio Transfer Factor (BTF) is a constant to describe the relationship between chemical substance in a tissue and the rate of ingestion to body of particular toxic agent (chemical substance). Often, the concentration forms a linear or straight line as the rate of chemical ingestion inreases as well. Thus at this case, the BTF is constant. I will make this simpler, BTF is a ratio between the amount of chemical per amount of body weight (mg A/kg_tissue) and the rate of ingestion of chemical entering the body (mg A/day. If you do not follow previous post, you are probably unfamiliar with A, A is representing toxic chemicals. I suggest you read the example about physiologically based pharmacokinetics, part 1, part 2 and part 3, especially this example is related to those examples as well. Read the rest of this entry »

Last post we have already talked about physiologically based pharmacokinetics example part 1 and part 2. These two posts give example on how to calculate the concentration of a suspected toxic chemicals within our digestive tract inside our body. They include the scheme starting from stomach and flow blood and kidneys. Just to refresh memory, this chemical enters the body, goes passing stomach before actually absorbed by blood for metabolism and the rest is sent to kidneys to be urinated. Read the rest of this entry »

After simple calculation on previous post physiologicaly based pharmacokinetics part 1, we now try to compute the concentration of a chemical substance A in blood and in the kidney. Assume that 0.5 mg A is at equillibrium and distributed between the blood and the kidneys. Let us assume to total blood volume in rats is equal 500 ml. Under assumption that blood and water have approximately the same density (1 g/ml), 500 ml of blood is the same with 50 mg blood. Read the rest of this entry »