Have to carboxylation for PEG, how?

More Kyungsun Ha's questions See All

Is there a generalized method to derive current-mode model of any DC-DC converters?

Hi all, As new DC-DC converters are being proposed, associated control method should be proposed and based on the small-model signal analysis of the DC-DC converters. Using average space state...

06 January 2021 7,247 3 View

How to avoid protein precipitation during Ni-NTA binding step?

Hi everyone, I am purifying an 18 kDa protein (his-tag). The protein expresses very well and I am able to get a clean 18kDa band in SDS Page gel after purification (attached picture). However,...

11 October 2020 3,189 6 View

Whether analysis with CB-SEM by AMOS will have better results comparing with PLS-SEM?

With your experiences, which one will have better results, CB-SEM or PLS SEM?

15 September 2020 8,092 5 View

Is there In-plane anisotropy of Amorphous CoFeB thin film?

I made CoFeB thin film on PMMA. The film thickness is from 100 nm to 10 nm. To measure magnetic properties, an M-H loop according to the angle was obtained using a VSM. However, the graph by angle...

27 July 2020 1,480 3 View

How to determine intention to use a new technology?

Hello, I am doing a research on new technologies and I would like to know how to determine the percentage of people that intend to use a new technology. I know about models like TAM, UTAUT, UTAUT2...

26 February 2020 1,381 10 View

I'm looking for an antibody. can I know where to buy?

Hello, I'm looking for some antibody, CLB-CAg 69. it is a anti-factor VIII antibody whose epitope is A2 domain of FVIII. However, I cannot get this. Can I know where to buy?

15 January 2020 3,325 3 View

"Safe" value of Vgs in sub-threshold design (4.5nUT < Vgs - Vth < -2nUT)?

Hello, Usually, by biasing Vgs < Vthreshold of MOSFET, we can push MOS into sub-threshold region. My curious question is: How much value of Vgs is "good" as a "rule of thumb"? I have referenced...

29 December 2019 9,143 1 View

Can an associate editor become in charge of a submitted manuscript where 1/4 of the total references were associated with his/her own??

Is it appropriate to have Person A as an Associate Editor of a submitted manuscript - where 1/4 of the total references are his/her own and who has been a co-author with the corresponding author...

14 December 2019 7,092 3 View

Which paper/book is best to study sub-threshold operation and model of MOSs devices?

Dear all, There are lots of published work on sub-threshold operation and models of MOS devices (example: on Journal of Solid-State Circuits, IEEE). For a good and highly-credited one, could you...

08 December 2019 5,968 5 View

What is your recommendation for an English editing service?

As I am not a native English speaker, normally, I am advised to use English editing services before submitting my manuscript to the journal. Recently, I got some bad experiences with the service I...

28 November 2019 7,039 11 View

How to compare two groups with only two measurements?

Hiiiii everyone! I have an enquiry on statistical analysis. I was looking for many forum and it's still cannot solve my problem. I want to compare means of two groups of data but only with two...

03 March 2021 8,796 3 View

What's the best way to measure growth rates in House sparrow chicks from day 2 to day 10?

What's the best way to measure growth rates in House sparrow chicks from day 2 to day 10? Since, the growth curve from day 2 to 10 won't be like the "Logistic curve" it might not follow logistic...

03 March 2021 1,401 3 View

How to increase a model accuracy ?

dear community, my model is based feature extraction from non stationary signals using discrete Wavelet Transform and then using statistical features then machine learning classifiers in order to...

03 March 2021 6,994 5 View

Chlorinated organic formation in odor control scrubbers using hypochlorite?

I'm involved in a study of odor control technologies for municipal wastewater treatment plant. One of the control options involves a chemical 2-stage (acid/alkaline) packed bed scrubber. The...

03 March 2021 3,661 2 View

1. What is the impact of having different scales in a survey? and how can we solve this problem before and after data collection (Literature)?

1. What is the impact of having different scales in a survey? and how can we solve this problem before and after data collection (Literature-based reflection)? Thank you for your time and for...

03 March 2021 2,870 3 View

What degree of missing data in a particular case/participant results in Expectation-Maximisation no longer working?

I'm dealing with a mediation model and am using the PROCESS module in SPSS. Due to SPSS and PROCESS being limited in the imputation methods - being unable to handle multiple imputation - the other...

02 March 2021 4,362 1 View

What solvent can I used for Paal Knorr reaction between 6-amino hexanoic acid and 2.5 hexanedione?

I am try to make the Paal Knorr reaction between 2.5 hexnedione and 6-amino hexanoic acid, my problem is type of solvent to use, because 6-hexaminohexanoic acid is soluble in water but I am not...

02 March 2021 4,443 2 View

Can NFL theorem be valid in infinite search space in ML?

NFL theorem is valid for algorithms training in fixed training set. However, the general characteristic of algorithms in expanded or open dataset has not been proved yet. Could you show your...

01 March 2021 1,189 3 View

Ester cleavage conditions?

Hi all, I need to cleave the ester in Ethyl 2-amino-1H-imidazole-5-carboxylate to make the carboxylic acid and retrieve the product from solution to use in downstream applications of linking to...

01 March 2021 8,766 3 View

Does anyone know how to plot my station to a section plot on Ocean Data View (ODV)?

I made a vertical section plot with WOA .nc file on ODV, and now I want to plot my stations (csv. file) in it. Does anyone know how to import my points to the section? They are two different...

01 March 2021 3,610 1 View

Michael G. Weller

From my point of view, the best way would be to use a PEG-NHS ester, which can be obtained commercially from different companies.

http://www.rapp-polymere.com/#index.php?id=1202¤cy=asd

Laszlo Jicsinszky

Hi Kyungsun,

You can prepare peg-carboxylate using TEMPO, NaBr and Na-hypochlorite (hypo, chlorox).

Dissolve peg in hypo and and add NaBr and a couple of percent of tempo in a fridge.

doi:10.1021/la9609231; 10.1021/ma050290+

The last one was reproduced successfully by myself in the preparation of CD-rotaxanes.

Good luck,

Laszlo