Estimate the molecular/formula weight of DNA based on its length in base pair (bp)

This is just an estimation, i.e. 650.
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How to calculate Molarity and Number of DNA molecules

• Calculate the molecular weight of DNA molecule

A double stranded DNA of 100 bp will have an estimated molecular/formula weight = 100 bp x 650/bp = 65,000. Note that 650 is the molecular weight of one base pair.
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• Calculate the Molarity of DNA solution

To calculate molarity of DNA, e.g. 100 µg/ml (equivalent to 0.1 g/l) of 100 bp DNA will corresponds to 0.1/65000 Molar = 1.5 µM DNA (equivalent to 1.5 µmol/l).
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• Calculate the number of DNA molecules in a volume of DNA solution

To calculate the numbers of DNA molecules in 1 µl (equivalent to 1 x 10^-6 l) of 1.5 µM DNA, use the Avagadro number to convert mol to the number of molecules. First, determine the mol of DNA in 1 µl of 1.5 µmol/l DNA solution, e.g. 1.5 x 10^-6 x 10^-6 = 1.5 x 10^-12 mol. Next, determine number of DNA molecules, e.g. 1.5 x 10^-12 x 6.023 x 10^23 = 9.03 x 10^11 DNA molecules. That is equivalent to 0.9 trillion DNA molecules.
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• Calculate the number of DNA molecules based on mass

If I have a mass of DNA molecule, e.g. 135 pg of 500 bp dsDNA, how many DNA molecules is there? First, determine the molecular weight, i.e. 500 bp x 650/bp = 325,000. Note that 135 pg is equivalent to 135 x 10^-12 g. Next, determine the mol of DNA, i.e. 135 x 10^-12 / 325,000 = 4.15 x 10^-16 mol. In a mole, there is 6.023 x 10^23 molecules, thus the amount of DNA molecules is 4.15 x 10^-16 x 6.023 x 10^23 = 250 million DNA molecules.
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This is for my own reference.

Inspiring story about Robert Langer

This is a story about Robert Langer,  "Engineer of Change" by TheScientist. 

At times, it's so challenging to stay in Science. If you don't publish, it's difficult to stay on to do research, as you might get penalized during job application or interview (for not having enough publications). I'm struggling with that now and it's demoralizing to get no rejection (no news).

I have to remind myself that it's all about having the right attitude (to get through the day). If indeed there is genuine love and passion for Science and the believe that our contribution will benefit mankind, environment and future, I guess going at different callings (opportunity that came knocking during the downs) will eventually lead us back to Science. For now, I'm applying for more options than just relying on research.

This article helped

Regret is when you don't do anything about your regrets

We have our regrets, but as long as we are alive. Regrets are transient. There is never a too-late for anything, even when time is running out. 

Just don't give up...

Biology is akin to History, but worst...

Thought you hated History? What's with events and sequence of events and the numbering in years etc.? Drives you crazy, no? 

Biology is worst. If you are into genes and its function in signaling pathways, you will need to pull your hair. Let me explain.. 

In history, a historical person such as Napoleon is none other than Napoleon. In Biology, a gene can have shitty lot of aliases and these names were amended several times in history. Try searching in the archive for a gene and it will kill you prematurely because you will "vomit blood" (due to extreme trauma to the heart). Also, you have Napoleon 1, 2, 3, 4 and a hell lot more that is involved in different aspect of event. They are cousins that are expressed in different spatiotemporal fashion and they might co-mingle at a niche. Confused?

It doesn't end. A gene in an event interacts with other genes, and each of the latter genes has its own aliases, cousins, twins etc.. Worst, each of the above genes has a function (or functional classification) and these too are historically amended. Imagine calling Napoleon as a Commander (analogy to function) in a period and then calling him again as Napoleon the "killer". In Biology, you also cluster genes together and then de-cluster them or overhaul the entire classification. The list is so long....

The ultimate worst scenario of all is that, there are gazillion historians (biologists) writing accounts of their studies. Your head will explode going through all these accounts, or venturing into unfamiliar territory...

Bioinformatics helped, but not enough. Google helped but not good enough. That's because gene acronyms sometimes clashes and bring hell to the reader. 

So, Biology is fun if you are into history and have the knack and liking in decoding...

Feeling nauseated while writing thesis

Symptoms include hair pulling, cursing, jumping up and down for no apparent reason, palpitation, increased myopia, rocketing astigmatism, migraine and the associated paracetamol addiction, sleeplessness, cold sweat, head banging rage, severe denial syndrome, panic attack, extremely claustrophobic (after being cooped up and fixated in front of computer), giddiness, obese (such irony, the more you are stressed, the faster you gain fat especial when food is not a problem), uncontrolled deterioration of body odor (shower can't help, it's the hormone), bad breath (that can kill vermin), susceptible to procrastination, bored, hungry, and etc.

Prognosis is not good... 

The only treatment is to get over with it before permanent head damage progresses to being a veggie..

Oh heaven, please have some mercy...

Don't pent up negative energy from lab..

And blow it up on loved ones at home (who are clueless and innocent).

Show of hand, how many are guilty?

I am.

Just because they love you don't give you the right to misuse their love to vent out your frustrations and all other negative energy onto them...

You should (or I should) be giving it directly to the person who are making you feel down in the office (or lab)... except to your boss of course (unless you have found a new job)...

Give it straight to the person making you feeling down by telling him/her off. Give a piece of your mind rather than swallow it hard and blow up later. Don't be the implosive type.

You can be nice but firm in your stand and protect yourself from being led downward. Say "no" more often and mean it when you say "yes".

Good luck..

There is a reason for not labeling properly in the lab

The first time I encountered such example would be in the common cold room. A stretch of LB antibiotic plates were placed nicely on a rack. At the bottom pasted a note reading, "use at your own risk, plates not labeled as it was meant to".

I scratched my head seeking for a reason. It never took long to figure out that the note was meant for other "unauthorized" users. It is also very likely that this person had been victim of pilfer for a long time and it reached the threshold of being calm to irritation for him/her.

Rule: "Use and let use" means to replace what you took from others and don't be a parasite.

I have adopted this approach (mislabel or unlabel) not long after. That started when I realized that the solutions I prepared not long ago were pilfered and I was left with insufficient amount at the most crucial time of the experiment. It is upsetting, no?

When someone says give me 5 mins, it means

they will need a minimum of 5 mins of your time.

It would be impolite to start a timer to count down a five; and it would be impractical for the person asking (seeking) for the time to start timing you (because it would be disadvantageous to the seeker).

If you are busy, politely say no. No time for now.

If you are the seeker, be polite as not to place a number on the time you are asking the person. Five min? Who are you kidding, because most of the time, it is more than 5 min of that person's time?

I would take you seriously if you start your timer and say, "now, may i ask 5 min of your time?" That is practical but still inappropriate because the person you are asking will feel bad about it.

Ever get irked by telemarketers asking for 5 min of your time? They always waste 2 mins before getting to the point, e.g. insurance, stock, investment, marketing, etc...

Last, a polite way to ask for someone's time would be, "are you free to talk?", if yes, then go right to the point especially if you notice that the "yes" was given out of courtesy.

New Year Resolution in 2013

Finish my PhD dissertation and submission by July.

De-cluttered some posts

De-cluttered some posts today. Wish I could say the same with the stuff that bulking in the fridge...