• Energy Research

BACKGROUND Lead is still a major environmental and occupational health hazard, since it is extensively used in the production of paints, gasoline and cosmetics. This causes the metal to be ubiquitous in the environment, being found in the air, soil, and water, from which it can enter the human body by inhalation or ingestion. Absorbed lead is capable of altering the calcium levels in bone. The aim of this study was to demonstrate the effect of lead on bone calcium levels by measuring the reaction constant, Gibbs free energy, and enthalpy. METHODS This study was of pure experimental design using 100 male albino rats (Rattus norvegicus). The experimental animals were assigned by simple randomization to two groups, one group receiving lead acetate orally at a dosage of 100 mg/ kgBW, while the other group did not receive lead acetate. The intervention was given for 4 weeks and the rats were observed weekly for measurement of bone calcium levels by the permanganometric method. RESULTS This study found that k1 (hydroxyapatite dissociation rate constant) was 0.90 x 10-3 dt-1, and that k2 (hydroxyapatite association rate constant) was 6.16 x 10-3 dt-1 for the control group, whereas for the intervention group k1 = 26.20 x 10-3 dt-1 and k2 = 16.75 x 10-3 dt-1. Thermodynamically, the overall reaction was endergonic and endothermic (ΔG > 0 and ΔH > 0). CONCLUSIONS Lead exposure results in increased dissociation rate of bone in comparison with its association rate. Overall, the reaction was endergonic and endothermic (ΔG > 0 and ΔH > 0).

Biomolecules need long-lived far from equilibrium states to function. These states have a high Gibbs free energy that is used for biologically important functions such as catalysis and they need to live for a sufficiently long time, comparable to reactant diffusion times that vary from 100 ns on up, to enable the system to use this free energy. Many theories have been put forth to explain the longevity of these states, such as "Bose condensation", "spontaneous symmetry breakdown", "dissipative structures", solitons and so on. We have isolated such transient far-from equilibrium states in sperm whale myoglobin and measured the decays of these states as a function of time under vastly different conditions. Our studies have led us to a completely different mechanism for the longevity of these long-lived states, which is based on the idea that non-equilibrium states are examples of "broken ergodicity". Our experiments at low temperatures and high pressures prove the existence at short times are in broken ergodic states even at room temperature. These broken ergodic states give us a new mechanism for excited states to live long. The dynamics of these states in proteins involve structural hierarchies. The motions take so long because the system has to go through many levels of relaxation. This concept of "getting lost" in a hierarchy is quantified precisely through an unusual idea: we show that the number of proteins participating in the recombination reaction obeys a second order linear differential equation and use this to define and experimentally determine a frequency dependent friction coefficient The idea of using such a number as a generalized coordinate is consistent with modern ideas of friction. We can now make the following alternative statement: the motions are so slow because friction slows them down. There is no need for solitons. The idea that friction is the mechanism by which an excited state lives longer is a little startling because we are used to thinking of friction as a dissipative mechanism. Here, friction is used to stabilize excited states, an idea that is applicable to glasses and spin glasses as well.

A value for the free energy of activation, or G for the inversion of groups on the imino nitrogen of the title compounds was calculated from data obtained from variable temperature NMR. The coalescence temperature, Tc, is obtained as the temperature at which the non-equivalent methyl resonances of the title compounds collapse to a singlet. G is calculated from G =2.3RTc(10.32 + logTc/k) Eq.3 derived from the Eyring Equation. p-Methoxyphenylimino-2,2,4,4-tetramethyl 3-cyclobutanone (4) is found to possess an energy of activation equal to that of 18.55 kcal/mole with its temperature of coalescence at 118C. p-Nitrophenylimino-2,2,4,4-tetramethyl 3-cyclobutanone (5) is found to have an energy of activation for inversion to be 14.25 kcal/mole. The coalescence temperature found for the nitro derivative was found to be subsequently lower than that of the methoxy, 35C. The G value of N-(2,2,4,4-tetramethyl-3 -cyclobutanone)-p-toluenesulfonamide (16) was found to have a value no greater than 16.42 kcal/mole with a corresponding Tc value of 76C. Whereas, the N-(3,3-Dichloro-2,2,4,4-tetramethyl-3-cyclobutanone)- toluenesulfonamide (17) yielded a value of 15.32 kcal/mole for the inversion energy. The Tc was found to be 56C. The data support the hypothesis that lone pair orbital interaction in the transition state affect the free energy of inversion of groups attached to the imino nitrogen.

Recent advances in genome editing and metabolic engineering enabled a precise construction of de novo biosynthesis pathways for high-value natural products. One important design decision to make for the engineering of heterologous biosynthesis systems is concerned with which foreign metabolic genes to introduce into a given host organism. Although this decision must be made based on multifaceted factors, a major one is the suitability of pathways for the endogenous metabolism of a host organism, in part because the efficacy of heterologous biosynthesis is affected by competing endogenous pathways. To address this point, we developed an open-access web server called MRE (metabolic route explorer) that systematically searches for promising heterologous pathways by considering competing endogenous reactions in a given host organism. MRE utilizes reaction Gibbs free energy information. However, 25% of the reactions do not have accurate estimations or cannot be estimated. To address this issue, we developed a method called FC (fingerprint contribution) to provide a more accurate and complete estimation of the reaction free energy. To rationally design a productive heterologous biosynthesis system, it is essential to consider the suitability of foreign reactions for the specific endogenous metabolic infrastructure of a host. For a given pair of starting and desired compounds in a given chassis organism, MRE ranks biosynthesis routes from the perspective of the integration of new reactions into the endogenous metabolic system. For each promising heterologous biosynthesis pathway, MRE suggests actual enzymes for foreign metabolic reactions and generates information on competing endogenous reactions for the consumption of metabolites. The URL of MRE is http://www.cbrc.kaust.edu.sa/mre/. Accurate and wide-ranging prediction of thermodynamic parameters for biochemical reactions can facilitate deeper insights into the workings and the design of metabolic systems. Here, we introduce a machine learning method, referred to as fingerprint contribution (FC), with chemical fingerprint-based features for the prediction of the Gibbs free energy of biochemical reactions. From a large pool of 2D fingerprint-based features, this method systematically selects a small number of relevant ones and uses them to construct a regularized linear model. FC is freely available for download at http://sfb.kaust.edu.sa/Pages/Software.aspx.

June 1968. ; Sponsored by the National Science Foundation GA930.

Based on density functional theory and classical transition state theory, the reaction mechanism of NO reduction by H2 catalyzed by coke in hydrogen rich blast furnace was investigated. The results showed that the presence of active sites on the coke surface promoted the NO reduction reaction. Reactive oxygen species remaining on the coke edge inhibited the NO reaction after NO reduction. Both coke and H2 can release edge sites by reducing reactive oxygen species, but reactive oxygen species reduction by H2 requires a high barrier value of 634,3 kJ/mol, which is higher than that by coke.

Undergraduate honors thesis / Open Access ; According to the three laws of thermodynamics, energy cannot be created nor destroyed, only transformed into a different energy form; entropy, or disorder, of an isolated system is always increasing, thus making many reactions more spontaneous by containing a lower Gibbs Free Energy; and as the temperature approaches absolute zero, the entropy becomes constant and no change occurs. If the entropy of the universe, an isolated system, is supposed to always be increasing, how can evolution occur where these simple molecules join together to create complex molecules, cells, tissues, and organisms if all these seem to be very organized and ordered, thus demonstrating a decrease in disorder, or entropy, in the system? Through the conduction of literature research and various real-life biochemical examples, the explanation of how the cells and other ordered structures were able to be created as well as the analysis of evolution and creation of life will both be able to explain how despite being seemingly unlikely to be created, the life that emerged approximately 3.7 billion years ago not only occurred spontaneously but will continue to grow and evolve. Depending on how one defines the system and its surroundings, different understandings and explanations of this apparent improbable development will be reached and expounded upon in this paper. ; S. Daniel Abraham Honors Program