I will give a briefly review of just two projects of the one hundred or more projects presented that day.

Plasma Electrolytic Oxidation Used for Hidroxyapatite Thin Film Formation on Ti-6Al-4V and γ-TiAl Alloys

Poster Presenter: Ana Mosquera

Nowadays biomaterials have attracted the attention of many scientists because their applications are broad and seem to be promising. Bone healing is one of those applications. Among the materials used for this purpose are:  silica mesoporous materials specially, SBA-15 and MCM-48, Si films, among others. According to Ana, in this specific project they used Ti-6Al-4V and γ-TiAl alloys to study the growth of hydroxyapatite  (Ca₁₀(PO₄)₆(OH)₂)  on the surface of the alloys. Why Hydroxiapatite? As far as I understood, it is because it promotes bone regeneration and accelerates the bone healing process. Moreover, hydroxapatite chemical composition resembles part of that found in bones tissue. The idea of coating the surface of the alloy with hydroxiapatite comes because the properties provided by titanium oxide itself (material used for bone healing applications) such as: surface area, thickness and adherence preferable in such materials, were poor in comparison with other materials used for bone healing applications.   The research project is really interesting and I hope that it could be implemented in a near future. Ana was very secure while presenting.

Functional Analysis of Rhesus Macaca Mulatta Collagenase(MMP1) and Gelatinase (MMP2) Domains, Important for Eye Development, Vision and Ocular Diseases

Poster Presenter: Angiemar Maldonado

The principal objective of Angimar’s research work was to study matrix metalloproteases (MMPs) , extracellular enzymes  with the ability to degrade structural proteins in the extracellular matrix, with the aim to inhibit its function as an effort to develop therapeutic treatments for some ocular diseases. According to Angimar , they study the Maccaca Mulatta animal to see which MMPs sequences are conserved , and based on that results they developed primers to detect the MMP genes using electronic PCR, which is a computational procedure to identify sequence tagged sites.  As far as I understand they have to perform future research on the MMP functionality by detecting the enzymatic activity of the metalloprotease and use aptamers to investigate the inhibition of the MMP. Angimar’s poster fulfilled with all the requirements, and she was very aware of what she was exposing and explaining. It is very important to highlight again, that this project intends to design drugs for treat ocular disease such as Glaucoma.

Please feel free to make suggestions

Abstract

Pollution of waters and soils due to 2,4,6-trinitrotolune (TNT) residues, and the generation of  a large quantity of used tires are two environmental problems that threaten the world. The aim of this work was to evaluate the use of a rubber-based activated carbon (RAC) obtained from shredded waste tire rubber and a silica based mesoporous material known as MCM-41 for the adsorption of TNT from aqueous solutions. The RAC was prepared by pyrolysis of shredded tire rubber and subsequent CO2 activation, while the MCM-41 was synthesized by the templating technique using tetraethyl orthosilicate (TEOS) as silica source and cetyltrimethylammonium chloride (CTAC) as template. Basic characterization of RAC and MCM-41 was performed by Scanning Electron Microscopy (SEM), Thermal Gravimetric Analysis (TGA), Fourier Transform Infrared FT-IR spectroscopy and N2-BET (Brunauer, Emmet & Teller) analysis. Adsorptions tests were performed on both materials using 3 to 100 mg/L TNT aqueous solutions. TNT was measured by UV spectrophotometry. The adsorption of TNT using RAC as adsorbent was superior to that of the adsorption using MCM-41 which shown a lower interacation whith TNT. The adsorption isotherms obtained were compared with Freundlich and Langmuir models. The interaction energy value (29.3 ±0.3 kJ/mol) obtained for RAC and TNT, shows that a physisorption process is favored. Our results suggest that the waste tire rubber based AC could be used for the adsorption of TNT as a good alternative in environmental cleaning applications. Future work will be focused on the degradation of the TNT adsorbed. In addition, the use of MCM-41 prepared with a different template will be evaluated looking for a better  MCM-41-TNT interaction.

As an overview, I will describe some of the work done last semester. The research was focused on the synthesis and characterization of a mesoporous material called MCM-41. The material was synthesized for the study of its adsorption efficiency on TNT. I have done few trials regarding to the adsorption of TNT on MCM-41 . Consequently I have set as the following goals for this semester: finishing the experiments regarding to the adsorption efficiency of MCM-41, to prepare more activated carbon in order to enhance its surface area, to evaluate other compounds such as the explosive RDX and some chemicals warfare agents’ simulants in terms of its removal from aqueous solution using our rubber-based activated carbon as adsorbent. These compounds are described to be dangerous to human health and nature. Finally, another project in mind is to study the interaction adsorbate-adsorbent energy by means of Thermo Gravimetric Analysis.

The work I will be doing this semester is similar to that of the last semester, in the sense that we still concern in environmental issues, as it is in the removal of threat materials from water.

Here is something new.

In my last blog entry I was talking about the importance of using pyrolyzed tire rubber (TGP) for the removal of TNT ( 2,4,6-trinitrotoluene) from aqueous solutions.  However we took a break of using TGP, and started to evaluate another mesoporous material,   with great potential of use. The material created approximately in the 90’s, MCM-41  by  Mobil Corporation of Matter  was evaluated in this work  in terms of synthesis complexity and characterization. The synthesis of this material requires almost five days for completely processing, for me that amount of days means a lot. A short view of the synthesis process can be appreciated in the Figure above. The mechanism shown above resembles the famous Liquid Crystal tinplating (LCT) mechanism.  Characterization of the material was based on TGA analysis to see if the template was successfully removed and for evaluate thermal stability of the material. BET analysis were also carried out, this assay provides a lot of information regarding to; the pore size of the material , the N₂ adsorption-desorption properties and also pore distribution of the MCM-41. For structure identity and elucidation, XRD will be made on January at the Chemical Engineer laboratories facilities.  The application of MCM-41 as adsorbent for TNT, was preliminary evaluated and adsorption was successfully. For those interested in materials wit Bio- applications, I recommend this dissertation:

-            Katiyar. A.  Development of novel mesoporous silicates for bioseparations and biocatalysis. Dissertation submitted for Chemical and Materials Engineering Department .Cincinnati , USA. 2008. P 45-49

-          Principal Focused in the SBA-15 (Santa Barbara Amorphous )Material characterization and applications  as sorbent  for chromatography analysis.

RANKING: 4.0 /5

TGA- Thermal gravimetry Anlaysis

BET- Braunner, Emmet  and Teller. Scientists that invented the BET Model for surface area determination of materials.

XRD- X-ray diffraction assay

  Among other things ….

This semester has been the worst semester ever, principally due to those days we missed because of the strike carried out at my Collage. Therefore all the dates scheduled in the academic agenda were moved ahead.   However, everything was possible until the last day, as today. I passed the deadline for the last blog entry, but here I am posting this thoughts for you , to know that  there is a huge amount of things that  I have learned this semester, not only  in research skills , but life. We people, especially me need to learn to distribute the time for everything; Studies, Family, Research, Organizations, and Friends.

 I spend more time with academic issues than family, at the extent that this four years of study has passed away without noticing how supportive was to have my family around me.  Hopefully I’m still having one semester left to enjoy and give all my efforts and dedication to my research and family. My principal expectation for next semester is to fulfill the duties with Biominds blog. My apologies for not submit this on time.

The disposal of waste tires is one of the many environmental problems affecting our Bioplanet. Millions of scrap tires are stored in stockpiles in USA and other countries and due to their properties particularly durability and no biodegradability at all, make the dumping process difficult. In addition to the fire risk involved with the stockpiling practices, It is known that scrap tires can be breeding ground for transmitting disease pests such as mosquitoes and rodents. In order to face the problem, some research efforts have been focused in the use of shredded tires as raw material for the preparation of activate char. This char could be used as an adsorbent for remediation processes of waste waters containing organic pollutants. In our project, the shredded tire rubber is pyrolyzed and the carbonaceous residue (the char) is then employed as adsorbent. We are studying the adsorption of TNT from aqueous solutions to evaluate the char performance compared with a commercial activated carbon. Since TNT and waste tires pollution are two huge environmental problems in USA and other countries, to face these two environmental problems at the same time is our sound approach. Furthermore, our research efforts are also focused in the study of the degradation process of TNT so that encompass its conversion in less dangerous derivative compounds.

Note: TNT is in the EPA list of priority pollutants.

My progress: 3 in the 1-5 scale

Since the main topic of my project has not been changed, I’m still using the same technique for the quantification of TNT adsorbed on the adsorbent, such as UV-VIS spectroscopy.  The difference in the  project for this semster is that the material being used is not derived form shredded tire rubber, but made by means of a synthesis. The product of the synthesis results to be a white solid which is then carbonized in order to make it a mesoporous material for adsorption purposes.

Characterization of the material is in progress. But adsorption tests seem to be not so promising which means that the synthesis of the material called (MCM41) has to be repeated   hoping to get some new results.  According to my objectives   I have achieved at least a 10 % of the main goals.

“If your research project is not working does not mean that you’re losing your time, means that it is more challenging and interesting, otherwise other people has been done it already”

Sorry for the delay.

My research during the Summer.

This summer was one of the best summers I have ever had, since I had the opportunity to participate in an undergraduate research program at the University of Minnesota, Twin Cities. This was my first time doing an internship and I can tell that the experience was very enlightening.  From my point of view the first two weeks were tough, because everything was new. But once you get used to the people and your laboratory everything is just so great! 

My work was about in the developing of fluorous sensing membrane solid contact Ion Selective electrodes ( SC-ISEs) with three dimensionally ordered macroporous (3DOM) carbon as the solid contact. The intention of the electrode is to detect perlfuorualkyl acids in aqueous solutions reaching low detection limits.  The reason we were focused on these compounds was because they are distributed world-wide; they do not degrade easily and are bio-accumulative.

My electrode shows response with a detection limit of 6.11×10^-7 M . This is very interesting because this detection limit could be further improved since 3DOM carbon-contacted ISEs provide very stable potentials and low detection limits, on the level of ppt for Ag⁺.  

Based on my experience and the new knowledge about this subject I have some goals in mind for this semester.

1. Keep working with  The removal of TNT in aqueous solutions using shredded r tire rubber as the adsorbent.
2. Use a new adsorbent material for absorbance capacity comparison with the commercial activated carbon.
3. Explore the use of PVC membrane ISEs for the detection of the Meisenheimer anion from TNT. 

As a synopsis my research last semester involved the preparation of an adsorbent based on shredded tire rubber. The resulting material was a carbonized tire which showed an adsorption capacity of the 88% which is not bad for a 99% compare with commercial activated carbon.  The material was characterized and adsorption isotherms and kinetics experiments were carried out.  During the summer my mentor took advantage on the project and synthesized a new material in order to be used this semester for comparison purposes.

Muy buena pregunta. Resulta que después de que el TNT se adhiere en el adsorbente se puede hidrolizar con NaOH, transformando el TNT.

En fin la experiencia fue bien enriquecedora.

Hay veces que no todo nos sale como queremos y tenemos que repetir el experimento. Me he dado cuenta que en los laboratorios de investigación debemos tener mucha paciencia y tratar de hacer las cosas bien, no queremos desperdiciar reactivo, algunos son caros o prepararlos cuesta trabajo. Así que una de las cosas que he tenido que afrontar es el estrés. Solo me paso una vez, que llegue al laboratorio queriendo hacer las cosas bien y rápido y fue peor, lo hice mal y pues perdí el tiempo. Mi mentor me dijo, toma un descanso y regresa más tarde. Eso fue lo que hice  y funciona, me relaje y cuando regrese todo salio nítido. 

Así que como consejo general, nuestra visión como investigadores a nivel sub-graduado es trazarnos metas cortas para lograr las grades. Poco a poco llegaremos al resultado final y coger las cosas con su debida calma.

Para el semestre que viene espero poder comenzar con la segunda parte del proyecto estudiando la Hidrólisis del TNT en medio básico.

http://es.geocities.com/fisicas/historia/citas_cientificos.htm

http://es.wikipedia.org/wiki/Trinitrotolueno

¿Qué hago en el curso de investigación… ?

Comencemos por saber la definición de Explosivo,

Un explosivo es una sustancia que se puede transformar a gas mediante alteraciones externas tales como fricción y calor liberando radiación, calor, o presión en un tiempo corto. Los explosivos se clasifican de acuerdo a su composición química. Están los explosivos de alto orden y bajo orden. En nuestro laboratorio trabajamos con un explosivo de alto orden muy fácil de identificar, por sus siglas de TNT, (2,4,6-trinitrotolueno) o en notación IUPAC 2,4,6-trinitrometilbenceno y como dice mi profesor de química orgánica “para fines culturales” posee una simetría de C_2v y momento dipolar 1.37 D (Larson et. al, 2008).

Trazas de este contaminante están presentes en aguas y en suelos debido a su gran uso como explosivo en diferentes aplicaciones como lo fue en la segunda guerra mundial.

Nuestro objetivo es buscar la manera de remover el TNT de aguas contaminadas usando un adsorbente barato y efectivo.

Cuando nos referimos a adsorbente estamos hablando del material capaz de retener las moléculas de TNT en su superficie mediante el proceso de adsorción.

Como adsorbente usamos carbón activado obtenido de la pirólisis de la goma triturada.

El trabajo en equipo…

Nuestro grupo de investigación es bastante grande, consta del profesor, luego le siguen los estudiantes graduados los cuales cada uno tiene aproximadamente 3 estudiantes sub-graduados y claro no olvido a la secretaria administrativa que nos ha ayudado un montón.

Actualmente trabajo con un estudiante graduado y otra estudiante sub-graduada para un total de 3 personas trabajando bajo el mismo proyecto.

Para que todo funcione bien cada uno debe poner de su parte y colaborar con lo que le corresponde. A esto me refiero con comunicarse con el mentor graduado y hacer cita de cuando nos reuniremos para hacer los experimentos y el análisis de resultados. Colaborar, comunicarse, entenderse, y tener mucha paciencia el uno con los otros es lo que un equipo debe lograr y trabajar por tener. Esto es fundamental en todo trabajo en grupo no tan solo a este nivel.

Como estudiante mi mayor obstáculo ha sido el manejo del tiempo. Hay que sacar tiempo para correr el experimento, para escribir en el “blog”, para el “ poster” (si aplica), para trabajar, para las tareas de las calases y para estudiar. Así que aunque tratemos de no dejar las cosas para lo último sé que se nos hace difícil pero de esto es que aprendemos. Considero que para poder colaborar eficientemente debemos aprender a ajustar nuestro tiempo y rendirlo al máximo.

La carrera es larga… pero no imposible.