The Belousov-Zhabotinsky (BZ) reaction is a classical oscillatory reaction that is the subject of many studies. One of its applications is to model other oscillatory processes, such as circadian rhythm. More often than not, experiments done on people are impractical, thus requiring simulations or modeling to enlighten the world on the unknown. A study of the effects of magnetic fields on the BZ reaction is presented. Magnetic fields create a huge impact on our lives, so much so that without them we may not function properly. It is not practical to expose people to diverse magnetic environments, such as outer-space, since an assay that assesses this requires multiple readings as well as the ability to allow another person to do it. Therefore, the Belousov-Zhabotinsky reaction, a Helmholtz coil, petri dishes, and a timer were used to provide clues as to how magnetic fields affect oscillating reactions. Our results indicate that the BZ reaction is a good model to replicate oscillatory biological reactions. Furthermore, the experimental conclusion is that reactions exposed to strong magnetic fields will oscillate slower than those exposed to weak magnetic fields.

The Briggs-Rauscher (BR) oscillatory reaction is one of the more interesting and colorful oscillatory reactions. It has surpassed the demonstration realm, as it has found use as a method to assess antioxidant capacity. However, this application as an antioxidant assay is limited to water-soluble samples. In the constant search for different, novel applications, we report the effects of various sample solvents on the behavior of the BR reaction. Our investigation looked at how changes in the solvent used to dissolve samples altered the time intervals of BR reaction’s oscillations. The solvents used were ethanol, isopropanol, 1-propanol, acetone, and acetonitrile. Addition of ethanol had no effect on the BR oscillations. Isopropanol, 1-propanol, and acetone shorten the oscillation time. A test using acetonitrile discarded solvent polarity effects. Our results suggest that solvents that accelerate the enol pathway rate affect the oscillations of the BR reaction. Finally, samples can be safely dissolved in ethanol and used in the BR reaction.

Mighty Fruits: Antioxidant Performance of Various Fruits

Jason Alvarodiaz, Jennifer Cerda, Christine Curiac, and Luis C. Fernandez-Torres

School of Science Technology, and Engineering Management, St. Thomas University, Miami Gardens, FL 33054

Antioxidants help fight free-radicals, which are produced by stress and later can induce many health problems. L-Ascorbic acid (Vitamin C) is a great antioxidant, and it can be found in a vast variety of fruits. Additionally, vitamin C is marketed as an over-the-counter remedy for the common cold. This motivates our desire to understand vitamin C’s antioxidant properties. This investigation presents the antioxidant capacity of various fruits that are known to be sources of vitamin C, and their comparison to pure vitamin C using the Briggs-Rauscher (BR) oscillatory reaction. The antioxidant species scavenge free radicals formed in the BR reaction, lengthening the time intervals of the reaction’s oscillations; the higher the antioxidant capacity, the longer the oscillation delays. The samples that were tested were: L- Ascorbic acid, Sunny-D^®, red grape juice, white grape juice, pineapple juice with pulp, pineapple juice without pulp, mango juice, and kiwi juice. Pure vitamin C could only be tested at low concentrations, as high concentrations completely interrupt the BR reaction. Kiwi exhibited the best antioxidant capacity of the tested samples, followed by mango juice. The antioxidant performance of orange juice resembled that of vitamin C the most. This result suggests that vitamin C is the main antioxidant present in orange juice. The other fruits exhibited antioxidant performances different to pure vitamin C. We ascribe these observations to the presence of other molecules, such as flavonoids and tannins, which also show antioxidant capacity.

Structure – Activity Relationships (SARs) of Antioxidant Molecules

Luis E. Castellar, Langeda Bontemps, Leslie Robinson, and Luis C. Fernandez-Torres

School of Science, Technology, and Engineering Management, St. Thomas University, Miami Gardens, FL 33054

The public’s demand for antioxidant supplements has increased recently. As more of these supplements hit the market, an understanding of what makes a molecule a good antioxidant is paramount. The aim of this research project is to evaluate the antioxidant capacity of several phenols and related derivatives using the Briggs-Rauscher (BR) oscillatory reaction. The antioxidant species scavenge free radicals formed in the BR reaction, lengthening the time intervals of the reaction’s oscillations; the higher the antioxidant capacity, the longer the oscillation delays. In phenol structures, the amount of hydroxyl (OH) withdrawing groups affects the antioxidant capacity. By adding a hydroxyl group in a specific ring position, such as ortho or para, an increase of antioxidant capacity was observed. Previous research supports that ortho substitution of an electron donor increases the stability of the phenol radicals. Our results showed that meta substituted phenols were the most active antioxidants. We rationalize this observation by considering the low pH (~2) of the Briggs-Rauscher reaction. It was also noticed that a monophenol showed less antioxidant capacity than a polyphenol structure. Finally, we observed that the number of OH substituent does affect the antioxidant capacity.

Antioxidant Capacity of Selected Teas and Cocoa

James Hankemeyer, Kasey Rivera, Kelnisha Lightbourne, Sara Salamah, and Luis C. Fernandez-Torres

School of Science, Technology, and Engineering Management, St. Thomas University, Miami Gardens, FL 33054

Diverse teas are consumed around the world for their calming, soothing effects. Many people attribute curative properties to tea. The same can be said for cocoa, and its processed form chocolate. Furthermore, these attributed health-giving properties are suggested to come from their antioxidant properties. This study presents the determination of the antioxidant capacity of selected teas (Camellia sinensis) and cocoa (Theobroma cacao), and comparing those results to a caffeine standard. The Briggs-Rauscher (BR) oscillating reaction was used to determine the antioxidant capacity of the samples. The antioxidant species scavenge free radicals formed in the BR reaction, lengthening the time intervals of the reaction’s oscillations; the higher the antioxidant capacity, the longer the oscillation delays. The samples consisted of aqueous preparations of Green tea, Black tea, Cocoa (pure powder), and Dark chocolate. To analyze the results we used the Relative Antioxidant Performance (RAP), where the slopes of the samples were compared to the caffeine standard. We hypothesized that the aqueous preparations of the samples would exhibit antioxidant capacity. Our hypothesis was proven correct, with green tea showing consistently higher RAP than decaffeinated green tea, and dark chocolate exhibiting slightly more antioxidant capacity than pure cocoa powder. Black tea proved to be less antioxidant than green tea. These observations suggest that antioxidant properties are present, and could be a plausible pathway to their attributed health-giving properties. Finally, these preparations are complex mixtures of natural ingredients; therefore, we should not dismiss any potential synergistic effects between different ingredients.

Powerful Plants: Antioxidant Capacity of Selected Plants

Christine Curiac, Jason Alvarodiaz, Langeda Bontemps, Luis Castellar, Jennifer Cerda, Ana Figuereo, Chelsea Trost, and Luis C. Fernandez-Torres

School of Science, Technology, and Engineering Management, St. Thomas University, Miami Gardens, FL 33054

Different cultures from around the world have used plants from their natural surroundings to treat different ailments. The action mechanisms of these natural remedies are diverse, yet many studies suggest their antioxidant properties bring about their effectiveness. This project presents the determination of the antioxidant capacity of selected plants, and comparing those results to a Trolox standard. The Briggs-Rauscher (BR) oscillating reaction was used to determine the antioxidant capacity of the samples. The antioxidant species scavenge free radicals formed in the BR reaction, lengthening the time intervals of the reaction’s oscillations; the higher the antioxidant capacity, the longer the oscillation delays. The samples consisted of aqueous and ethanolic extracts from the leaves of Annona muricata, Moringa oleifera, Petiveria alliacea, Hamelia patens, and Gynura bicolor. To analyze the results we used the Relative Antioxidant Performance (RAP), where the slopes of the samples were compared to the Trolox standard. Since most of these leaves are traditionally used in teas, we hypothesized that the aqueous extracts would exhibit the highest antioxidant capacity. Except for the aqueous extracts of Moringa oleifera and Petiveria alliacea, our hypothesis was proven correct, with Hamelia patens showing the highest RAP. These results were attributed to the solubility in water of the active antioxidant molecules versus their solubility in ethanol. These observations suggest that antioxidant properties are present, and could be a plausible pathway to their therapeutic properties. Furthermore, these extracts are complex mixtures of natural ingredients; therefore, we should not dismiss any potential synergistic effects between different ingredients.

Antioxidant Capacity of Common Dietary Supplements

Ana Figuereo, Marie Roche, Leonardo Albertini, Chelsea Trost, and Luis C. Fernandez-Torres

School of Science, Technology, and Engineering Management, St. Thomas University, Miami Gardens, FL 33054

Today’s health-conscious society consumes a wide variety of dietary supplements in order to improve quality of life. An increasing number of these supplements are marketed as antioxidants. Therefore, it is of great importance to understand the performance of these supplements as antioxidants. This investigation presents the antioxidant capacity of several common dietary supplements using the Briggs-Rauscher (BR) oscillatory reaction. The antioxidant species scavenge free radicals formed in the BR reaction, lengthening the time intervals of the reaction’s oscillations; the higher the antioxidant capacity, the longer the oscillation delays. The samples experimented, Beta carotene, Lutein, Quercetin, Folic Acid, and L-Glutathione, all exhibit antioxidant activity. Trolox, a water-soluble form of vitamin E, was established as the standard to assess each supplement’s antioxidant capacity. It was noted that the time delay within the BR reaction oscillations was significantly affected with increasing concentrations of each substance. Also, sodium iodate proved to be better than potassium iodate in the BR reaction, as precipitation was not a factor that altered results in the BR reaction. In addition the antioxidant capacity was quantified by the calculation of the Relative Antioxidant Performance (RAP), which measures the sample slope over the standard slope or the slope of Trolox. Finally, we observed that exposure to light can affect the antioxidant capacity.

Determination of the Antioxidant Capacity of Coffee

Kelnisha Lightbourne, Sara Salamah, James Hankemeyer, Kasey Rivera and Luis C. Fernandez-Torres

School of Science, Technology, and Engineering Management, St. Thomas University, Miami Gardens, FL 33054

Coffee (Coffea arabica) is one of the most consumed drinks in our society. It is grown in many regions around the world, developing different flavors and aromas. Its active ingredient, caffeine, is sought after for its stimulating properties, and purported therapeutic effects. This study presents the determination of the antioxidant capacity of coffee, and the assessment of those results using a caffeine standard. The Briggs-Rauscher (BR) oscillating reaction was used to determine the antioxidant capacity of the different coffee samples. The antioxidant species scavenge free radicals formed in the BR reaction, lengthening the time intervals of the reaction’s oscillations; the higher the antioxidant capacity, the longer the oscillation delays. The samples consisted of caffeine (5%), and freshly brewed samples of espresso coffee (1%), decaf (1%), Costa Rican coffee (5%), Cuban Split Pea Blend (1%) and Jamaican Blue Mountain Coffee (5%). All samples show antioxidant capacity. To analyze the results we used the Relative Antioxidant Performance (RAP), where the slopes of the samples were compared to the caffeine standard. Jamaican Blue Mountain Coffee exhibited the highest RAP at the 5% dilution; Cuban blend was the highest RAP at the 1% dilution. To further examine the Cuban blend, we tested roasted split peas (10%), and they showed no antioxidant capacity. These observations suggest that antioxidant properties are present in coffee, and could be an explanation to its attributed health-giving properties. Finally, brewed coffee is a complex mixture of natural ingredients; therefore, we should not dismiss any potential synergistic effects between different ingredients.

In reinforcement learning, the exploration/exploitation dilemma is a very crucial issue, which can be described as searching between the exploration of the environment to find more profitable actions, and the exploitation of the best empirical actions for the current state. We focus on the single trajectory reinforcement learning problem where an agent is interacting with a partially unknown MDP over single trajectories, and try to deal with the exploration/exploitation in this setting. Given the reward function, we try to find a good E/E strategy to address the MDPs under some MDP distribution. This is achieved by selecting the best strategy in mean over a potential MDP distribution from a large set of candidate strategies, which is done by exploiting single trajectories drawn from plenty of MDPs. In this paper, we mainly make the following contributions: 1) we discuss the strategy-selector algorithm based on formula set and polynomial function.2) we provide the theoretical and experimental regret analysis of the learned strategy under an given MDP distribution. 3) we compare these methods with the ``state-of-the-art" Bayesian RL method experimentally.

The development of vaccines against Chagas disease during the past years have provided a partial control of Trypanosoma cruzi infection. GPI-anchored T. cruzi genes are conserved in all T. cruzi life cycle stages and were tested as vaccine candidates in previous studies, they elicited humoral and cellular mediated immune responses and controlled parasitemia in mice. Herein we tested multi-component DNA-prime/DNA-boost vaccine (TcVac1) which comprises two plasmids encoding GPI-anchored genes (TcG2 and TcG4) from Trypanosoma cruzi; two plasmids encoding adjuvant cytokines (IL12 and GM-CSF). To identify the best route of vaccine application in BALB/c mouse model, two vaccination protocols were compared; a) intradermal injection/electroporation (IDE), b) intramuscular injection (IM). Humoral immune response was evaluated through assessing titers of anti-TcG2 and TcG4 IgG and IgG subtypes (IgG1, IgG2a and IgG2b) antibodies through ELISA assay, using recombinant TcG2 and TcG4 as sensitizing antigens. Evaluation of immune cellular response was assessed through a lymphocyte proliferation assay, after exposure of vaccinated mice splenocytes to the studied antigens. Finally, histopathological and common clinical signs were carried on for vaccinated and infected mice groups. Results demonstrated higher antibody titers for IDE mice groups with a switch from a Th1 (IgG2b/IgG1>1) to Th2 (IgG2b/IgG1<1) immune profile from pre- to post-infection experimental periods, as well as a higher lymphocyte proliferation favoring IDE> IM mice groups. Histopathological evaluation of experimental mice hearts showed areas of myocardial necrosis and degenerative changes associated with severe inflammatory cell infiltrates for control infected mice groups to slight or moderate infiltrates for vaccinated-infected groups. In conclusion electroporation technique enhances the TcVac1 vaccine uptake leading to high specific immune response in both pre- and post-infection periods compared to the intramuscular technique.