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Maru Sandoval M.Sc. – Our First Graduate Thesis


It is with great pride that I’d like to announce that for the first time we have a Masters Student graduated from this Comp.Chem. lab: María Eugenia “Maru” Sandoval-Salinas has finished her graduate studies and just last Friday defended her thesis admirably earning not only the degree of Masters of Science in Chemistry but doing so with the highest honors given by the National Autonomous University of Mexico.

Maru’s thesis is for many reasons a landmark in this lab not only because it is the first graduate thesis published from our lab but also the first document on our work about the study of Photosynthesis, a long sought after endeavor now closer to publication. It must also be said that Maru came to this lab when she was an undergraduate student five years ago when I just recently joined UNAM as a researcher fresh out of a postdoc stay. After getting her B.Sc. degree and publishing an article in JCTC (DOI: 10.1021/ct4004178) she now is about to publish more papers that I’m sure will be as highly ranked as the previous one. Thus, Maru was a pioneer in our lab giving it a vote of confidence when we had little to nothing to show for; thanks to her hard work and confidence, along with that of the students who have followed her, we managed to succeed as a consolidated research group in the field of computational chemistry.

More specifically, her thesis centered around finding a mechanism for the excitonic transference between pigments (bacteriochlorophyl-a, BChl-a) in the Fenna-Matthews-Olson (FMO) complex, a protein trimer with seven BChl-a molecules in each monomer, located between the antenna complex and the reaction center in green sulfur bacteria. Among the possible mechanisms explored were Förster’s theory, a modification to Marcus’ theory and finally we explored the possibility of Singlet Fission occurring between adjacent molecules with the help of Dr. David Casanova from the Basque Country University where Maru took a short research stay last autumn. Since nature doesn’t conform to any specific mechanism -specially in a complex arrangement such as the FMO- then it could be possible that a combination of the above might also occur but lets just wait for the papers to be published to discuss it. Calculations were performed through the TD-DFT and the C-DFT formalisms using G09 and Q-Chem; comparing experimental data in CH3OH (SMD implicit calculations with the SVWN5 functional) were undertaken previously for selection of the level of theory.

Now, after two original theses written and successfully defended, an article published in JCTC and more in process, at least five posters, a couple of oral presentations and countless hours at her desk, Maru will go pursuit a PhD abroad where I’m sure she will exceed anyone’s expectations with her work, drive, dedication and scientific curiosity. Thank you, Maru, for all your hard work and trust when this lab needed it the most, we wish you the best for you earn it. You will surely be missed.

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A personal artistic impression of the CompChem Landscape 


In a nutshell, computational chemistry models are about depicting, reproducing and predicting the electronic-based molecular reality. I had this conversation with my students last week and at some point I drew a parallel between them and art in terms of how such reality is approached.

Semi empirical methods
Prehistoric wall paintings depict a coarse aspect of reality without any detail but nevertheless we can draw some conclusions from the images. In the most sophisticated of these images, the cave paintings in Altamira, we can discern a bison, or could it be a bull? but definitely not a giraffe nor a whale, most in the same way Hückel´s method provides an ad hoc picture of π electron density without any regard of the σ portion of the electron density or the conformational possibilities (s-cis and s-trans 1,3-butadiene have the same Hückel description).

More sophisticated semi-empirical Hamiltonians like PM3 or PM6 have better parametrizations and hence yield better results. We are still replacing a lot of information for experimental or adjusted parameters but we still cannot truly adopt it as truthful. Take this pre-medieval painting of one of the first Kings of England, Aelred the Unready. It is, by today standards, a good children´s drawing and not a royal portrait, we now see more detail and can discern many more features yielding a better description of a human figure than those found in Altamira or Egypt.

Ethelred_the_Unready

Æthelred the Unready King of England ca. 1000 BC

 

Hartree-Fock
HF is the simplest of ab initio methods, meaning that no experimental results or adjustable parameters are introduced. Even more so, from the HF equations for a multi-electron system that complies with Pauli’s exclusion principle the exchange operator arises as a new quantum feature of matter with no classical analogue. Still, there are some shortcomings. Correlation energy is disregarded and most results vary according to the basis set employed. Take the impressionist movement, specially in France: In Monet´s Lady with Umbrella we have a more complicated composition, we observe many more features and although we have a better description of color composition some details, like her face, remain obscure. The impressionists are characterized by their broad strokes, the thicker the strokes the harder it is to observe details similar to what happens in HF when we change from a small to a large basis set, respectively.

Claude_Monet_023

Woman with a parasol – Her face or the identity of the flowers at her feet are indistinguishable yet we might be safe to say its springtime.

CI (Configurations Interaction)
Extension of HF to a multi-reference method yields better results. In CI we take the original guess wavefunction -as expressed through a Slater Determinant- and extend it with one or many more wavefunctions; thus a linear combination of Slater Determinants gives rise to a broader description of the ground state because other electronic configurations are involved to include more details like the ionic and covalent pictures (configurations). The more terms we include the more real the results feel. If we take classical figurative paintings we have a similar result; most of these paintings are constituted of many elements and the more realistically each element is captured the more real the whole composition looks even if some are just merely indicated.

Flaming_June,_by_Frederic_Lord_Leighton_(1830-1896)

Flaming June by Lord Leighton – Extreme details on the fabrics and the sea in the background makes us oblivious to the less detailed foot

CCSD(T) full-CI, CASPT2

In Edwards Much’s the scream, we might think we have lost some information again and went back to impressionism but we know this is actually an expressionist painting; we can now not only observe details of the figurative portion of the image but Munch has captured his subject´s fear in the form of distorsions on the subjective reality. In this way, CCSD(T), full-CI and CASPT2 methods provide a description of the ground as well as the excited states which -in experimental reality- are only accessed through a perturbation of the elecron density by electromagnetic radiation. Something resembling radiation has perturbated the subject in The Scream rendering him frightened and wondering how to return to his ground state or if such thing will be even possible.

The_Scream

The Scream by Edward Munch – what sort of perturbation got this guy’s fears out?

 

Density Functional Methods

At least due to its widespread use, DFT has risen as the preferred method. One of the reasons behind its success is the reduced computing time when compared to previous ab initio methods. So DFT is pretty much like photography, in which reality is captured in full but only apparently after selecting a given lens, an exposition, a filter, shutter speed and the occasional Photoshop for correcting issues such as aliasing. In photography, as in DFT, all details concerning the procedure or method for capturing an uncanny reproduction of reality must be stated in every case for reproduction purposes.

Now, in the end it all comes down to Magritte’s Pipe. Ceci n’est pas une pipe -or, ‘this is not a pipe’- reminds us that painting as with modeling we don’t get reality but rather a depiction of it. In this famous painting we look at an image that in our heads resembles that of a pipe but we cannot grab it, fill it with tobacco and smoke it.

MagrittePipe

This isn’t even Magritte’s painting! Let alone a pipe

The image above is a digital file, which translated becomes a scaled reproduction of an image painted by Magritte in which we see the 2D projection of the image of an object that reminds us of a pipe. In fact, the real name of this work is The Treachery of Images, definitely quite an epistemology problem on perception and knowledge but before I get too metaphysical I should finish this post.

Can you find where cubism or surrealism should be placed? with MPn methods, perhaps?

More interns!


I’ve been neglecting this blog a lot lately! It would seem as little or nothing is going on in our lab but it’s quite the opposite, a lot of good stuff is going on and most of the excitement comes from the results obtained by a few more interns.

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Eduardo Cruz

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Alberto Olmedo

Alberto and Eduardo came just as the previous group of interns left. They’re both undergrad students in Pharmaceutical Sciences at Universidad de la Cañada in southern Mexico. My good friend, Dr. María del Carmen Hernández, referred them to me to do a stay during their summer vacations. They are taking where the previous interns (Paulina, Eliana, Javier and Daniel) left and have now obtained the interaction energies for five different host-guest aducts for 3-phenyl-1H-[1]bezofuro[3,2-x]pyrazole, a tyrosine III kinase inhibitor, currently under research for the treatment of leukemia, better known to us as GTP. As before, our molecular carriers are a wide selection of functionalized-calix[n]arenes. These calculations turned out to be rather lengthy; they were all performed at the B97D/6-31+G(d,p) level of theory in order to account for dispersion forces in pi-pi interactions between the aromatic rings in both species.

The third recent addition to our lab is Monserrat Enriquez, who is a PhD student under the supervision of my good friend Dr. Eddie López-Honorato (if you haven’t checked his blog on nuclear energy and materials for nuclear reactions containment go now and follow it; encourage him to post more often!). Monserrat will be co-advised by me. Her project lies within the scope of molecular recognition, materials recovery and bioremediation; calculations and simulations will help the experimental team to point the synthesis of sequestrating agents in the right direction, or, at the very least, to have a better understanding of the forces and interactions lying beneath the formation of such complex structures.

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Monserrat Enriquez

Last but not least, Luis Enrique is back with a vengeance! He is determined to finish his study on other tyrosine kinase inhibitor drugs. Luis Enrique is an undergrad Chemistry student here in Toluca at the Autonomous Mexico State University, so he will come on his spare time and work from home every now and then; who knows! maybe he’ll end up with a dissertation by the time he finishes his undergrad studies!

But I’m to be left alone pretty soon, as Alberto and Eduardo will stay for a couple of weeks more and Luis Enrique will be here on his spare time. Monserrat will leave on Friday back to Saltillo in Northern Mexico to continue working on the experimental part of her research while working on her calculations from a distance.

Thanks to them for their invaluable help in the development of our research group, for their enthusiasm and hard work. You are now a part of this lab and its doors will always welcome you back!

Summer internships are Over


For the last five weeks we had guests in our lab coming from different places of the country: Tepic (west), León (Center) and Mexico City (Right in the middle!). During those five weeks they worked in the field of computational chemistry helping our research efforts with a couple of drug carrying molecules. They learned about computational chemistry and drug design; about wavefunctions and density functionals; about population analysis and vibrational frequency analysis. Dead hours were a bit complicated to handle because the convergence of each calculation takes some time and, as opposed to a wet-chemistry lab, I couldn’t just ask them to purify starting materials or distillate solvents. A question to other theoretical/computational chemists: What could I have asked young undergrad students (with backgrounds ranging from engineering to pharmacy) to do during those dead hours? What did I do wrong? Anyway, they manage to spend a good time since they all got along quite well.

Now they are back to their hometowns getting ready for the congress, hosted by the same organization that awarded them the stipend to come and spend their summer with us (The Dolphin Program / Programa Delfín) as well as to going back to school in a few more weeks. I asked* them to write a guest post for the blog telling their experience, which is presented below. Thanks to you all for choosing our lab to get your internship this summer!

Javier Camacho (Mexico City)

Javier_Delfin_2013Hi, I’m Javier from ESIQIE-IPN
The dolphin program has given me the opportunity to experience how is to be in a high-level scientific research. Login to CCIQS next to the imminent Dr. Joaquin Barroso Flores, left me a pleasant experience. The great contribution that gives this line of research has allowed me to meet new horizons, beyond the area of engineering, to which I belong.
The theoretical chemistry and computational chemistry together, are a great weapon to develop virtual optimizations that allow us to find drug transport agents, without making the vast amount of laboratory tests that are required. Explaining that this is one of the many applications that can be used.
To undertake this experience has left me very satisfied, be guiding a person who likes his work and want to show what he knows, it makes me very happy. After these long weeks of work and perseverance, with certainty affirm the interesting and productive it is to be part of the investigation in Mexico.
I thank the Dolphin Program, gives CCIQS the UAEM-UNAM and Dr. Joaquin for opening the doors to this great opportunity to start my story as a researcher.

 

Paulina Pintado (Tepic, Nayarit)

la fotoHi my name’s Paulina and I came as part of Dolphin Research Program that gives the opportunity of participates in a real work of investigation with a professional at the topic. In this occasion I came to work with Ph.D. Joaquin Barroso in a small project of his line of research; namely theoretical drug carriers design. In this six weeks besides to learn more aspects about my career, in this case Theoretical Chemistry applied to pharmaceutical industry; I tested the experience of travel to another town just by myself, live with people from different parts of the country with distinct customs and visit few places of the town.
This summer will always be memorable ‘cause this internship is an important event for my professional experience and also for my personal development and I hope many others students have the courage to try get into the world of scientific research.
So just remains for me to thank to Ph.D. Joaquin Barroso for giving me the chance to do this internship in his lab I hope you continue having success in your work, I feel pretty glad to met him and my others research’s mates.

 

 

Daniel Carteño (Mexico City)

Ey my name’s  Daniel and this summer of  2013  i had been the opportunity to do a research  internship in Toluca under P.H.D. Joaquin Barroso, and during this period of time I´ve learnt a bit about His research work, not only this is  an important experience for my educational history, but it also is for my personal life. Learnt about theoretical chemistry open my vision of this discipline, because when I thought about chemistry I´ve never imagine a computational laboratory, this the most important part, nowadays the researches have been removed due to  they are so expensive and finally the conclusion  is not expected, when you use a super computer like me and my work team used, it doesn’t matter if you have a mistake  or do something wrong, only you have to write again the keywords and the only thing you spend is time. Even in Mexico theoretical chemistry is not famous in my opinion is a useful work tool. This research internship was highly satisfactory and hope do it again i´m glad

*Their contributions were completely voluntary and no editing of their original texts has been made.

Summer Internships


This week has been a happy one since four new additions to our staff have been made, at least for the summer, that is. Paulina, Eliana, Javier and Daniel have come to our lab from various different towns across the nation to spend six weeks working hard in small projects related to our lines of research; namely theoretical drug carriers design. This time the drug under study is known as GTP or 3-phenyl(1H-[1]benzofuro[3,2]pyrazole and calixarenes will once again act as the potential carriers.

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Left to Right: Daniel, Javier, Paulina and Eliana
(Summer Interns – 2013)

They all came as part of the Dolphin Research Summer Program (link in Spanish only) in which college students spend a few weeks doing research in the lab of their choosing. This is the first time I participate as a tutor and I find it a great opportunity for young students to get familiar with certain aspects of science they wont learn inside school.

So far these past three days have been quite intense with them learning how to edit and submit a Gaussian calculation in a Linux environment. I’ve already taught them about geometry optimizations, frequency analysis, (natural) population analysis and Fukui reactivity indices calculation. There is much more to learn still, of course, but so far so good. I believe the major drawback so far has been their own eagerness since they’d like to have all the data imediately! Unfortunately they’ll have to wait for their initial calculations to converge. We started this week by doing some simple analysis of all the properties described above for the Cytosine-Guanine base pair at the B97D/6-31+G(d,p) level of theory. Luckily their calculation crashed promptly, and I find that lucky because that gave me the opportunity to teach them how to relaunch a failed calculation, which, unfortunatelly will happen more often than not.

So, welcome guys! Thanks for choosing this lab for doing your internships. I hope you find our research interesting and motivating, may this be the first step into a full time research career. Also, kudos to the Dolphin Staff for helping promote science in young Mexican students. Stay tuned for a guest post from all of them once they finish their time here.

First graduated student!


Today is truly a landmark in our lab because on this day, María Eugenia “Maru” Sandoval-Salinas has defended her thesis and has thus obtained her B. Sc. in Chemistry. She is the first student under my supervision to achieve this goal, and I hope it won’t be long until we get some more, although now the bar has been set quite high. For the time being, Maru is pursuing a career in the pharmaceutical industry but has every intention of coming back to the lab for her Masters degree; she has a reserved spot here with us at CCIQS.

Hard work pays off - We wait for you to come back for your Masters Degree!

Hard work pays off – We wait for you to come back for your Masters Degree!

Maru’s thesis deals mainly, but not exclusively, with calculating the interaction energies of calix- and thia-calix[n]arenes with the tyrosine kinase inhibitor Imatinib, which is widely used in the treatment of Chronic Myeloid Leukemia (CML), in order to rationally design a drug delivery agent for this drug. Her work is (a huge) part of an article currently under revision that I only wish had been published before her defense. Still, we await for that paper to be published in the next few weeks.

Throughout her stay at our lab, Maru was a dedicated student willing to learn new skills every time. As she replied today to one of the questions: “it’s not so much how many calculations I got right, but how many I got wrong!“. I find deep meaning in this sentence, perhaps deep enough as to consider it an aphorism, because indeed the more we try the more we fail, and the more we fail the more we learn and the closer we get to success.

Congratulations, Maru! I personally thank you for all the hard work invested in your thesis, all the long hours in front of the computer and your disposition to learn and work during the last 1.5 years. I’m certain you’ll find success in any venture you undertake; and I’m certain of it because you never stop trying.

Taking the Oath after being unanimously approved

Taking the Oath after being unanimously approved

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