question

I want to isolate DNA from the bacterias (both Gram positive and negative bacterias) in drinking water. Do you have any protocols which is good for this purpose? THank you very much!

I have made a correlation between group A and B and the pearsson coefficient constant, r, is at 0.97. The values are expression levels and hence they are non-parametric. I wonder how can i calculate the p-value of this correlation between group A and B? I know how to calculate the p-value for the difference between group A and B, but not for the correlation between group A and B.

Thanks for any inputs!

I am looking for any references talking about WESTERN BLOTTING, but i hardly find any in pubmed. Could it be that WESTERN BLOTTING is an old technique that is why old articles are deleted or not in use? Do you have any good ones that i can read?

I am not interested in some of the unknown websites talking about this topic, since i don't know if they are right about what they are saying. I need articles with references!

Thank you!

How can i make a histodiagram in Excel by using Microsoft Windows Version 2002? Or how can i make it, which softwares?

Thank you!

Dear all,

I have two independent and non normalized samples where one sample has n=30 and the other has n= 1. Due to both samples don't have a normality distribution so i have to use non-parametric methods. I plan using Mann-Whitney Test, but then it needs that both samples have to be larger than n=5 or both are lesser than n=5. In my case then i have n=30 and the other is n=1. What kind of statistical methods should i use to get a reliable answer?

I thank you alot!

Hope for a quick answer!

I have searched and searched till my eyes fall out, but can not find any recipes for making these solutions. Anyone can help me out?

1mM tributylphosphine

1%SDS

10 M Urea

These are the pituitary gland's proteins i need their sizes infos.

1. B actins

2. Folate receptor alpha subunits

do you have any ideas about them?

Where and how can i find sizes of pituitary glands' proteins? When i use Entrez or other bioinformatic sites, it only has human proteins and not specifically human pituitary glands' proteins.

Hope for ideas.

Thank you.

I am facing a problem where i am not sure if a specific protein like for example pituitary folate receptor alpha subunit has the same function, size and structure in any locations of a human body.

as i know a gene can have different start and end signal which means a transcript will end in different products then how come a specific pituitary protein will be identical to other places?

Any ideas are greatly appreciated.

I have planned to use 18S rRNA as the normalizer in RT-qPCR for validation of microarray results, do i have to use this same normalizer in my microarray assay?

Thank you.

Hi!

I already sent you my email address. It will be fine for me if you can put the links here or send me the mail.

Thanks!

Well' date=' what you are testing [i']for[/i] determines the test. If you are testing for a difference in means between samples, then you have to use a t-test.

 

The difference in sample sizes won't influence what test you need to use, but as it is such a large difference, it will weaken your experiment. The greatest power is achieved when the sample sizes are equal.

 

What are you measuring? i.e. are the data parametric or non-parametric?

Aww, someone adviced me to use U-test mann-Whitney, but i don't know if it is the best. What do you think about it? I am testing for the fold difference of some gene expressions between the treated samples (pituitary tumour samples) relative to the controll samples (pituitary normal samples). As i know the experiment must be non-parametric, since the populations don't have normal distributions. Or is it parametric?

You can consider my problem as this: I have two groups. Group A gets treatment while gropu B is the controll where it does not get treatment. In A i have 50 samples/observations (n=50) and in B i have 5 samples/observations (n=5). So what kind of tests should i use to compare group A versus group B?

Hope for your inputs and ideas!

Thank you.

I am stucked...

I would like to read these articles, but they need subscription. Is anyone out there that can give me a full text of them?

It will be of very great help for me.

http://www.eje-online.org/cgi/content/abstract/153/1/143

http://www.ncbi.nlm.nih.gov/entrez/query.f...864&query_hl=11

Thanks!

Okey, i am confused about this matter.

I have two different samples. One is 5 untreated/control samples (same kind) and the other is a 50 treated samples (same kind). I wonder what kind of statistic methods i can use to compare the results between them? I don't think that i can use ANOVA, since they need at least 3 different samples.

Besides i can not use T-test or Z-test either, since the former needs both samples to be at a small number n<30, while the latter needs both samples to be large n>30. My samples is n=5 (controll samples) and n=50 (treated samples).

Hope for inputs.

Thank you!

I need to make a solution of Glycerol (per liter) 150 g (1.26 g/ml), final conc 15 % w/v. And here comes the clue, the only thing we have is glycerin (and that's the same, I know that) but that's is liquid!

I have found that i should go this way: Glycerol/glycerin has a density of 1.25 gm/mL.

15 % (w/v) is equal to 150 gm/Liter = 12% (v/v).

(150 gm/L)/(1.25 gm/mL) = 120 mL of glycerol/L.

My question: Is gm the same as g? How do you get 15 % (w/v) Glycerol= 12% (v/v)glycerin ?

Hope for inputs.

Thank you.

Hello Everybody,

I am going to subgroup GH (Growth hormone releasing) pituitary adenomas according to their expression profiles by microarray and RT-qPCR. I do have 50 GH pituitary adenomas to subgroup and i wonder should i run all these 50 adenomas in the microarray to check their expression profiles or should i only take for example 5 of them to run in the microarray since they probably must have almost the same expression profiles? You know if i run all the 50 adenomas then it would take alot of time. What do you usually do when you have to subgroup a group of related things like in this case GH (Growth hormone releasing) pituitary adenomas?

Thanks for any input.

For a solution It says; VAPOR DENSITY: 1.3

Is VAPOR DENSITY the same as Density of that solution? And what is the unit of 1.3?

Hope for inputs.

Thanks.

anyone with good links of Microarrays?

thanks.

....

dear everybody!

i am very confused about this area and hope that you can help me out of this. for example this protocol:

1. Add sufficient bovine gamma globulin to each of eight test tubes to give you a calibration curve. Suggested values are 0, 10, 20, 30, 60, 90, 120 and 150 µg/ul protein.

2. Prepare 1:10 and 1:100 dilutions of the crude TDH prior to assay.Place 20, 40 and 60 µL of each TDH solution in separate test tubes.

3. Add water to a total volume of 150 µL in all tubes.

4. Add 5 mL of diluted dye reagent to each tube and vortex (carefully).

5. Incubate at room temperature for 5 minutes.

6. Transfer 200 µL from each sample and calibrator to duplicate wells on a microplate.

and from this we read the OD and make the calibration curve. my questions are:

1. both the standard and sample solutions are diluted when we add water and dye reagent. this means that the standard solutions do change from their standard concentrations ( 0, 10, 20, 30, 60, 90, 120 and 150 µg/ul ). how come i use this calibration curve to measure the sample concentrations when the standard solutions are further diluted than suggested? and should i take the dilution factor from water and dye reagent into account when i find the real sample protein concentrations or are the values i get from the curve my real sample concentrations?

2. how can i make a standard curve using excel? does the computer automatically make it for us or should we do it ourselves? if so, then i hope that you can help me with it.

thank you very much.

my book gives an example of how to find the concentration of OH- for transforming 99% benzoic acid to benzoate anion. it is difficult to understand how they get the answer, since there are no specified concentrations for the benzoic acid and benzoate anion, besides the way they write it is also difficult to understand. this is how they write:

the ability to separate a strong from weak acids depends on the acidity constants of the acids and the basicity constants of the bases as folllows. in the first equation, consider the ionization of benzoic acid, which has an equilibrium constant Ka of 6.8x10-5. the conversion of benzoic acid to the benzoate anion in the fourth equation is governed by the equilibrium constant K (Eq.5), obtained by the combining the third and fourth equations.

C6H5COOH + H2O -> <- C6H5COO- + H3O+ (Eq. 1)

Ka= [C6H5COO-][H3O+]/[C6H5COOH]=6.8x10-5, pKa=4.17 (Eq. 2)

Kw=[H3O+][OH- ]=10-14 (Eq. 3)

C6H5COOH + OH- -> <- C6H5COO- + H2O (Eq. 4)

K=[C6H5COO-]/[C6H5COOH][OH- ]=Ka/Kw=6.8x10-5/10-14=6.8x109 (Eq. 5)

if 99% of the benzoic acid is converted to C6H5COO- :

[C6H5COO-]/[C6H5COOH]=99/1 (Eq. 6)

then from Eq. 5 the hydroxide ion concentration would need to be 6.8x10-7M.

my question, how do they get [OH- ]= 6.8x10-7M ????

hope for any ideas and guidance!

thanks for helping!

...and yes i have tried, but can not figure out how do they think.

hello everybody!

i wonder what can i do to get my nucleotide sequence and aa of a gene being translated under each other so i can have a whole picture of which nucleotide belongs to the aa and which aa belongs to the nucleotide in a paper?

for example:

atg ttt tta ........

M P L ...........

this would be of great help, since the aa and protein sequence of a gene are in different places (databanks and even in the same databank) and i waste my time on translate every code into its aa.

hope you get my point!

thanks alot!

by the way here is the link; http://itsa.ucsf.edu/%7Ehdeacon/Stokesradius.html

the protocol:

Vg = volume not accessable to solvent (volume of the gel matrix)

Vg cannot be measured directly. However, it should apparant that:

Vg = Vt - volume accessable to solvent

We can measure the volume accessable to the solvent, using a small molecule such as acetone which can be easily visualized by a UV detector.

example:

Pharmacia Superose 6 column - volume accessable to solvent = 19.5 mL (measured with acetone)

Vg = Vt - 19.5 mL = 24.4 - 19.5 mL = 4.9 mL

---------------------------------------------------------------------------------------

hi guys!

i just find this calculation very unreasonable, since as we know Vt=Vi+Vg+Vo,

where Vt =total column volum, Vo= void volum due to EXTREMELY huge substances, Vg= volum of matrix and Vi=volum inside the beads due to EXTREMELY small substances.

my question is, how come we use acetone (small molecule) to determine both Vo and Vi, since Vg= Vt- (Vo+Vi)?

hopes for replies!

thanks!