Effects of site-directed PEGylation on L-asparaginase thermostability / Efeitos da PEGuilação sítio-dirigida na termoestabilidade da L-asparaginase

The enzyme L-asparaginase (ASNase) is broadly applied as a drug to treat acute lymphoblastic leukemia, as well as in the food industry to avoid acrylamide formation in baked and fried food. In the present work, ASNase was covalently attached to polyethylene glycol (PEG) of different molecular weights (ASNase-PEG-5, ASNase-PEG-10, ASNase-PEG-20, and ASNase-PEG-40) at the N-terminal portion (monoPEGylation). Native and PEGylated forms were analyzed regarding thermodynamics and thermostability based on enzyme activity measurements. ASNase (native and PEGylated) presented maximum activity at 40 °C and denaturation followed a first-order kinetics. Based on these results, the activation energy for denaturation (E*d) was estimated and higher values were observed for PEGylated forms compared to the native ASNase, highlighting the ASNase-PEG10 with a 4.24-fold increase (48.85 kJ.mol-1) in comparison to the native form (11.52 kJ.mol-1). The enzymes were evaluated by residual activity over time (21 days) under different storage temperatures (4 and 37 °C) and the PEGylated conjugates remained stable after the 21 days. Thermodynamic parameters like enthalpy (ΔH‡), entropy (ΔS‡) and Gibbs free energy (ΔG‡) of ASNase (native and PEGylated) irreversible denaturation were also investigated. Higher - and positive - values of Gibbs free energy were found for the PEGylated conjugates (61.21 a 63.45 kJ.mol-1), indicating that the process of denaturation was not spontaneous. Enthalpy also was higher for PEGylated conjugates (18.84 a 46.08 kJ.mol-1), demonstrating the protective role of PEGylation. As for entropy, the negative values were more elevated for native ASNase (-0.149 J/mol.K), pointing out that the denaturation process enhanced the randomness and aggregation of the system, which was observed by circular dichroism. Thus, PEGylation proved its potential to increase ASNase thermostability

A enzima L-asparaginase (ASNase) é amplamente usada como medicamento para tratamento da leucemia linfoblástica aguda, bem como na indústria de alimentos para evitar a formação de acrilamida em alimentos cozidos e fritos. No presente trabalho, ASNase foi covalentemente ligada ao polímero poli(etilenoglicol) (PEG) de diferentes massas moleculares (ASNase-PEG-5, ASNase-PEG- 10, ASNase-PEG-20, and ASNase-PEG-40) na região N-terminal (monoPEGuilação) a fim de se estudar os efeitos da PEGuilação na termoestabilidade da enzima. As formas PEGuiladas e nativa foram analisadas em relação à termodinâmica e termoestabilidade a partir de atividade enzimática. A ASNase (nativa e PEGuilada) apresentou atividade máxima a 40 °C e a desnaturação ocorreu por cinética de primeira ordem. Com base nesses resultados, a energia de ativação para desnaturação (E*d) foi estimada e maiores valores foram observados para as formas PEGuiladas em comparação à enzima nativa, destacando-se a ASNase-PEG10 com aumento de 4.24 vezes (48.85 kJ.mol-1) em comparação com a forma nativa in (11.52 kJ.mol mol-1). As enzimas foram avaliadas por sua atividade residual ao longo do tempo em diferentes temperaturas de armazenamento (4 e 37 °C) e os conjugados PEGuilados mostraram-se mais estáveis após os 21 dias de ensaio. Parâmetros termodinâmicos como entalpia (ΔH‡) de desnaturação irreversível foram analisados. Valores maiores - e ), entropia (ΔS‡) de desnaturação irreversível foram analisados. Valores maiores - e ) e energia livre de Gibbs (ΔG‡) de desnaturação irreversível foram analisados. Valores maiores - e positivos - da energia livre de Gibbs foram encontrados para os conjugados PEGuilados (61.21 a 63.45 kJ.mol-1), indicando que o processo de desnaturação não ocorreu de forma espontânea. A entalpia também foi maior para os conjugados PEGuilados (18.84 a 46.08 kJ.mol-1), demonstrando o efeito protetivo da PEGuilação. Já para a entropia, os valores negativos foram mais elevados para a ASNase nativa (-0.149 J/mol.K), apontando que o processo de desnaturação aumentou a aleatoriedade e agregação do sistema, o que foi confirmado pelo dicroísmo circular. Dessa forma, a PEGuilação revelou o seu potencial de aumento de termoestabilidade para a ASNase

Advances in the development of constraint-based genome-scale metabolic network models / 生物工程学报

Genome-scale metabolic network model (GSMM) is becoming an important tool for studying cellular metabolic characteristics, and remarkable advances in relevant theories and methods have been made. Recently, various constraint-based GSMMs that integrated genomic, transcriptomic, proteomic, and thermodynamic data have been developed. These developments, together with the theoretical breakthroughs, have greatly contributed to identification of target genes, systems metabolic engineering, drug discovery, understanding disease mechanism, and many others. This review summarizes how to incorporate transcriptomic, proteomic, and thermodynamic-constraints into GSMM, and illustrates the shortcomings and challenges of applying each of these methods. Finally, we illustrate how to develop and refine a fully integrated GSMM by incorporating transcriptomic, proteomic, and thermodynamic constraints, and discuss future perspectives of constraint-based GSMM.

Based on weak bond chemistry, the interaction mechanism between glycyrrhiza protein and berberine in water decocting process of Rhizoma Coptidis and Liquorice was investigated / 药学学报

The purpose of this study was to explore the interaction mechanism between glycyrrhiza protein and berberine in the decocting process of Rhizoma Coptidis and Liquorice and its effect on the pharmacodynamic effect. In this experiment, licorice crude protein was obtained from licorice decoction pieces, and it was found that licorice crude protein and berberine could form spherical supramolecular particles after decocting together. Morphological characterization was carried out by using Malvin particle size analyzer and emission scanning electron microscopy, and the supramolecular particles were observed to be nanoscale, which was significantly different from the morphology of licorice protein and berberine. The results of ultraviolet, infrared and fluorescence spectroscopy showed that the mechanism of molecular interaction was induced by weak bonds such as electrostatic attraction and hydrophobic interaction. Furthermore, the antimicrobial activity of berberine was significantly affected by the supramolecular particles of licorice protein-berberine, which were significantly different from the mechanical mixture. This study reveals the pharmacological value of macromolecular substances such as proteins in the decoction of licorice and Coptis chinensis from a new perspective, which is helpful to promote the secondary development of clinical effective prescriptions, especially the research on the pharmacological substance basis of classic famous prescriptions.

Investigation of Adsorption Properties of Five Macroporous Resins for Total Flavonoids in Epimedii Folium / 中国实验方剂学杂志

Objective::To compare the adsorption characteristics of different macroporous adsorption resins for the total flavonoids in Epimedii Folium, clarify the adsorption mechanism, and screen the optimal resin for the purification of total flavonoids in Epimedii Folium. Method::Taking the adsorption and desorption capacities of the total flavonoids in Epimedii Folium and five representative flavonoids (epimedin A, epimendin B, epimendin C, icariin, baohuoside Ⅰ) as indexes, static adsorption and dynamic adsorption experiments were conducted to compare the adsorption characteristics of five macroporous including HPD100, HPD600, AB-8, X-5 and D101.The adsorption kinetics of the selected resin was studied by using the pseudo-first-order, pseudo-second-order kinetic models and intraparticle diffusion model, and the thermodynamic process was analyzed by using the Langmuir and Freundlich isothermal adsorption models, which explored the adsorption mechanism of resin from the perspective of physical chemistry. Result::HPD100 macroporous resin had a better adsorption and desorption properties than the others. The adsorption process of HPD100 macroporous resin for total flavonoids in Epimedii Folium and five representative flavonoids conformed to the pseudo-second-order kinetic model. The adsorption thermodynamic process of HPD100 resin for total flavonoids of Epimedii Folium conformed to the Freundlich model, and for the sum of five representative flavonoids conformed to the Langmuir model. The adsorption process of HPD100 resin for total flavonoids in Epimedii Folium was the exothermic process dominated by physical adsorption, and the optimal adsorption temperature was 25 ℃. Conclusion::HPD100 macroporous resin has large adsorption capacity, easy desorption and clear adsorption mechanism, it is suitable for isolation and purification of total flavonoids in Epimedii Folium.

Meridian tropism of Scutellaria baicalensis based on molecular thermodynamic characteristics / 药学学报

The property of medicine is the "identity card" of traditional Chinese medicine (TCM), and the key to crack the theory of property of TCM. Based on molecular thermodynamics, the effects of interaction between TCM and organs in vitro were studied from the perspective of micro-energy release and absorption in order to construct a new idea of characterizing meridian theory. Scutellaria baicalensis, for example, application of isothermal titration calorimetry (ITC) were used to determine the energy changes during the interaction of Scutellaria baicalensis and its main active ingredient baicalin with brain, heart, lung, spleen and kidney in vitro, comparison including the association constant (Ka) and disassociation constant (Kd), combined with thermodynamic parameters, such as stoichiometry ratio (n), enthalpy change (ΔH), entropy change (ΔS), Gibbs free energy (ΔG), it is found that the interaction intensity between Scutellaria baicalensis and lung is significantly stronger than that of other organs, which is consistent with the theory of the return of Scutellaria baicalensis in ancient books. In addition, baicalin, the main active ingredient, showed the same action pattern as Scutellaria baicalensis. The thermodynamic parameters analysis showed that the action was a weak bond-induced spontaneous chemical binding reaction driven by both entropy and enthalpy. The results of specific curl measurement further proved the interaction between baicalin and lung, and were consistent with the results of ITC titration, indicating that ITC could be used to characterize the meridian tropism of TCM. Therefore, based on ITC, it is scientific and feasible to characterize the meridian of TCM by the energy change of the interaction between the decoction of TCM and its active components and the in vitro tissues respectively. This experiment provides a new idea for the discussion of meridian of TCM.

Salud y Enfermedad Mental: Del Corpus Hippocraticum a una aproximación termodinámica / Health and Mental Illness: From Corpus Hippocraticum to a thermodynamic approach

Se establece una relación entre conceptos básicos acerca de salud y enfermedad mental en los Tratados Hipocráticos y los elementos actuales de la termodinámica y de la cibernética, enlace que se formula a través de los aportes de autores como Maturana y Valera (autopoiesis y teleonomía) o Bergson (regularidades vs indeterminsmos). Se definen y caracterizan los fenómenos anancásticos y los estocásticos, destacándose su relación complementaria. Con un enfoque termodinámico se define a la enfermedad mental como una estructura que se impone hegemónicamente sobre el resto de las actividades mentales y consume la energía que regula el metabolismo restante de la persona afectada. Se aportan evidencias clínicas de las bondades de esta óptica, presentándose, por ejemplo, la ansiedad como una crisis entrópica y la depresión como interferencia de la teleonomía , al tiempo que los trastornos obsesivo-compulsivos son descritos desde una perspectiva cibernética. A lo largo del texto se le confiere mayor relevancia a la noción de la enfermedad mental como pathos hegemónico que absorbe recursos energéticos y disminuye las posibilidades de adaptación del afectado a su medio externo y de éxito en el afrontamiento de sus propias tensiones.

A link is traced between the basic concepts on health and mental illness in the Hippocratic Treaties and the current elements of thermodynamics and cybernetics, through the contributions of authors such as Maturana and Valera (autopoiesis and teleonomy) or Bergson (regularities vs. indeterminism). Anankastic and stochastic phenomena are defined and characterized, highlighting their complementary connection. Following a thermodynamic approach, a mental illness is defined as a structure that imposes itself on the rest of the mental activities and consumes the energy that regulates the remnants of the affected person s metabolism. Clinical evidences of the benefits of this perspective are given, presenting, for instance, anxiety as entropic crisis and depression as an interference of teleonomy , while obsessive-compulsive disorders are described from the cybernetic perspective. Throughout the text, the greatest relevance is conferred to the notion of mental illness as a hegemonic pathos that absorbs energy resources and diminishes the affected individuals possibilities of adaptation to their external environment, and of successfully coping with their own tensions.

Nucleação na formação de estruvita: estado da arte / Nucleation in the formation of struvite: state of art

RESUMO Estimativas recentes indicam que a duração de toda a reserva de rochas fosfatadas do planeta não ultrapassa 400 anos e que a produção de fertilizantes nitrogenados é insustentável energeticamente. Atualmente, o tratamento de esgoto está sendo visto como uma unidade de recuperação de recursos (água, energia e nutrientes) em vez de uma de final de tubo. Portanto, as tecnologias de recuperação devem ser priorizadas em relação às de remoção. Estruvita (fosfato de amônio e magnésio) é um cristal que pode ser produzido a partir do esgoto doméstico e tem maior eficiência agrícola do que os fertilizantes convencionais. Apesar de a cristalização ser um tema bastante estudado em todo o mundo e extremamente desenvolvido tecnologicamente, sua utilização na engenharia sanitária ainda não é comum, especialmente no Brasil. Um dos assuntos menos pesquisados na formação da estruvita é a nucleação. Portanto, o presente artigo traz uma revisão bibliográfica crítica e atual e mostra as lacunas no conhecimento sobre esse assunto.

ABSTRACT Recent estimation for the duration of global phosphate reserves does not exceed 400 years and the production of nitrogen fertilizers is energetically unsustainable. Nowadays, wastewater treatment plants have been seen as resource recovery facilities (water, energy and nutrients) instead of "end-of-pipe" utilities. Thus, nutrient-recovery technologies should be prioritized over the removal ones. Struvite (phosphate of ammonium and magnesium) is a crystal, produced from sewage, with a higher agricultural efficiency when compared to conventional fertilizers. Despite the crystallization is a topic extensively studied worldwide and highly technologically developed, its use in sanitary engineering is still not common, especially in Brazil. As the aspects related to struvite nucleation have been insufficiently studied, this paper presents a critical and updated literature review, and shows the gaps in the current knowledge about this topic.

Progress and application of metabolic network model based on enzyme constraints / 生物工程学报

Genome-scale metabolic network models have been successfully applied to guide metabolic engineering. However, the conventional flux balance analysis only considers stoichiometry and reaction direction constraints, and the simulation results cannot accurately describe certain phenomena such as overflow metabolism and diauxie growth on two substrates. Recently, researchers proposed new constraint-based methods to simulate the cellular behavior under different conditions more precisely by introducing new constraints such as limited enzyme content and thermodynamics feasibility. Here we review several enzyme-constrained models, giving a comprehensive introduction on the biological basis and mathematical representation for the enzyme constraint, the optimization function, the impact on the calculated flux distribution and their application in identification of metabolic engineering targets. The main problems in these existing methods and the perspectives on this emerging research field are also discussed. By introducing new constraints, metabolic network models can simulate and predict cellular behavior under various environmental and genetic perturbations more accurately, and thus can provide more reliable guidance to strain engineering.

Application of affinity chromatography and its mathematical model in study of active components of traditional Chinese medicine / 中国中药杂志

Affinity chromatography is characterized by its high specificity,high recovery rate and sensitivity,and it has been widely used in the selection of active ingredients of traditional Chinese medicine,separation and enrichment of low molecular weight sugars and protein peptides,research on mechanism of action and discovery of targets.This paper reviewed the application of affinity chromatography and its adsorption isotherm model,kinetic model and adsorption thermodynamic mechanism in the field of traditional Chinese medicine.This summarizes and provides thinking for comprehensive applications of affinity chromatography theory in the field of active ingredient screening,purification and medicine interaction.

Adsorption kinetics and thermodynamics of phenylethanoid glycosides on macroporous resins in the leaves of Callicarpa nudiflora

Objective: To investigate the adsorption kinetics and thermodynamic characteristics of phenylethanoid glycosides (PGs) in the leaves of Callicarpa nudiflora on macroporous resins and provide a reference for the separation and purification of these compounds. Methods: With adsorption and desorption ratio as indexes, optimum types of macroporous resin for purification of PGs were selected from 8 kinds of macroporous resins by static adsorption and desorption tests, and then adsorption kinetics model and adsorption isotherm model of PGs were established to investigate their adsorption processes. Results: SP-825 and SP-207 resin were selected and they have similar adsorption process for PGs. Both of them showed a fast adsorption in 0-60 min, a slow adsorption in 60-360 min, and an equilibrium adsorption stage after 360 min. Adsorption dynamic behavior was well described by quasi-second-order equation of both SP-825 and SP-207 macroporous resins, and adsorption rate was mainly controlled by liquid film diffusion and intraparticle diffusion. Equilibrium adsorption data fitted Langmuir and Freundlich isotherm equations well. Both of the two kinds of resins showed good adsorption properties for PGs, and the adsorption process belongs to favorable adsorption. Conclusions: Both of the kinetic model and thermodynamic model can well describe the adsorption process of SP-825 and SP-207 macroporous resins and the two resins were regarded as excellent adsorption resins for the purification of PGs from the leaves of Callicarpa nudiflora.

Thermal Inactivation of Crude Polyphenol Oxidases and Peroxidase from Three Tissues of Yellow-fleshed Cassava (Manihot esculenta Crantz) Root cv. Bocou 2

Aims: The objective of this work was to study the thermal inactivation of the polyphenol oxidase (PPO) and peroxidase (POD) activities of cassava (Manihot esculentaCrantz) root cv. Bocou 2 in order to preventenzymatic browning.Study Design: Crude PPO and POD from yellow-fleshed cassava root were subjected to heat treatment and their thermal inactivation characteristics were examined.Place and Duration of the Study: The study was conducted at Biocatalysisand Bioprocesses Laboratory, Food Science and Technology Unit, Nangui Abrogoua University Abidjan, Côte d’Ivoire, between January and December 2015.Methodology: The crude PPO and POD were extracted from three tissues (cortex, cambium and central pith) ofyellow-fleshed cassava root cv. Bocou 2. The thermal inactivation of these enzymatic activities was evaluated between 50 and 70 °C. The kinetic data of thermal inactivation and thermodynamics were analysed. Results: The t1/2-and D-values decreased with increasing temperature, indicating a faster inactivation of PPO and POD at higher temperatures. Z-values ranged from 16.10 to 27.70 °C and activation energy (Ea) from 73.37 to 129.66 kJ mol-1. Thermodynamic investigations indicated that the oxidation reactions involving these enzyme activities were: not spontaneous (?G > 0), slightly endothermic (?H > 0) and reversible (?S < 0).Conclusion: The PPO and POD activities from yellow-fleshed cassava root decreased due to heat denaturation with increasing temperature from 60 to 70 °C. These kinetic data can be used to prevent enzymatic browning in cassava roots.

Clinical application of thermography for energy balance in athletes - state of the art and new paradigms / Aplicação clínica da termografia para equilibrio energético em atletas - estado da arte e novos paradigmas / Aplicación clínica de la termografia para equilibrio energético en atletas - estado del arte y nuevos paradigmas

This article aims to describe the evolution of techniques that have enabled the proper application of the Laws of Thermodynamics for physical activity and athletes. The objective is to propose performance indicators to help add information to the current indices used in medicine and sports, such as the lactate threshold and maximum oxygen consumption. A number of analyses of the results obtained by the group were carried out for this purpose. Moreover, a discussion regarding which techniques would provide a better response to the measurements was analyzed. Some examples are the substitution of the treadmill running test with the stationary bicycle (known performed work), and a literature search in order to measure internal temperature more accurately. Level of Evidence V; Expert opinion.

Este artigo descreve a evolução de técnicas que possibilitaram a aplicação adequada das Leis da Termodinâmica às atividades físicas e aos atletas. O objetivo é propor indicadores de desempenho que ajudem a acrescentar informações aos índices atuais usados em medicina e nos esportes, como o limiar de lactato e o consumo máximo de oxigênio. Diversas análises dos resultados obtidos pelo grupo foram realizadas com essa finalidade. Além disso, procedeu-se à análise da discussão sobre quais técnicas proporcionariam resposta melhor às medições. Alguns exemplos são a substituição do teste de corrida em esteira pela bicicleta ergométrica (que sabidamente, pode ser usada para o trabalho), e a pesquisa da literatura para medir a temperatura interna com maior precisão. Nível de Evidência V; Opinião de especialista.

Este artículo describe la evolución de técnicas que posibilitaron la aplicación adecuada de las Leyes de la Termodinámica a las actividades físicas y a los atletas. El objetivo es proponer indicadores de desempeño que ayuden a acrecentar informaciones a los índices actuales usados en medicina y en los deportes, como el umbral de lactato y el consumo máximo de oxígeno. Fueron realizados diversos análisis de los resultados obtenidos por el grupo con esa finalidad. Además, se procedió al análisis de la discusión sobre qué técnicas proporcionarían respuesta mejor a las mediciones. Algunos ejemplos son la sustitución del test de carrera en cinta por la bicicleta ergométrica (que sabidamente, puede ser usada para el trabajo), y la investigación de la literatura para medir la temperatura interna con mayor precisión. Nivel de Evidencia V; Opinión de especialista.

In vitro rumen biohydrogenation kinetics of mixed linoleic and alfa-linolenic acids / Cinética de biohidrogenación ruminal in vitro de los ácidos linoleico y alfa-linolénico mezclados / Cinética de biohidrogenação ruminal in vitro dos ácidos linoleico e alfa-linolênico misturados

Abstract Background: Dietary linoleic (LA) and alpha-linolenic (LN) acids are extensively isomerized and hydrogenated by rumen microbes, and this activity can further contribute to the fatty acid profile of ruminant- derived food products. Objective: To evaluate the effects of LA:LN ratio in lipid supplements on the rumen biohydrogenation kinetics of LA and LN, as well as on the trans-vaccenic acid (VA) production, using an in vitro system. Methods: Rumen fluid was collected from a fistulated steer, diluted with incubation buffer, and then incubated with 500 mg of kikuyu grass (Cenchrus clandestinus) supplemented with 16.3 mg of different LA:LN mixtures (100:0, 75:25, 50:50, 25:75 or 0:100). Incubations were performed in triplicate for a period of 0, 2, 4, 6, 8 or 16 hours. Differences between treatments were evaluated in a completely randomized design. Alternatively, computational chemistry was used to determine the changes in the Gibbs free energy (ΔGrxn) at 39 °C for the principal steps of LA and LN ruminal biohydrogenation. Results: Partial replacement of LA by LN decreased the VA concentration and its accumulation rate; it also increased the stearic acid concentration and the rates of transfer from LA to conjugated linoleic acid (CLA), and from CLA to VA. The conversion from CLA to VA (ΔGrxn = -2.65 kJ/mol) was more spontaneous than that from trans-11, cis-15 octadecadienoic acid (TA) to VA (ΔGrxn = -0.29 kJ/mol). Conclusion: The LA:LN ratio in lipids can modulate LA and LN biohydrogenation (BH) kinetics, as well as the VA production in the rumen.

Resumen Antecedentes: los ácidos linoleico (LA) y alfa-linolénico (LN) de la dieta son extensivamente isomerizados y biohidrogenados por los microorganismos ruminales, lo cual puede contribuir al perfil de ácidos grasos de los productos derivados de rumiantes. Objetivo: evaluar el efecto de la relación LA:LN en suplementos lipídicos sobre la cinética de biohidrogenación ruminal del LA y LN, como también sobre la producción del ácido trans-vaccénico (VA), usando un sistema in vitro. Métodos: se colectó fluido ruminal de un toro fistulado, el cual fue diluido con buffer de incubación y posteriormente incubado con 500 mg de pasto kikuyo (Cenchrus clandestinus) suplementado con 16,3 mg de diferentes mezclas de LA:LN (100:0, 75:25, 50:50, 25:75, o 0:100). Las incubaciones fueron desarrolladas en triplicado durante 0, 2, 4, 6, 8 o 16 horas. Diferencias entre tratamientos fueron evaluadas mediante un modelo completamente al azar. Alternativamente, se determinaron los cambios en energía libre de Gibbs ( Δ Grxn) a 39 °C para los pasos principales de la biohidrogenación del LA y LN, usando química computacional. Resultados: la sustitución parcial de LA por LN disminuyó la concentración de VA y su tasa de acumulación, como también incrementó la concentración de ácido esteárico y las tasas de transferencia de LA para ácido linoleico conjugado (CLA) y de CLA para VA. La conversión de CLA para VA ( Δ Grxn = -2,65 kJ/mol) fue más espontánea que la conversión del ácido trans-11, cis-15 octadecadienóico (TA) para VA ( Δ Grxn = -0,29 kJ/mol). Conclusiones: la relación LA:LN en lípidos puede modular la cinética de biohidrogenación (BH) del LA y LN y la producción de VA en el rumen.

Resumo Antecedêntes: o ácido linoleico (LA) e alfa-linolênico (LN) da dieta, são extensivamente isomerizados e biohidrogenados pelos microorganismos do rúmen, o que pode contribuir ao perfil de ácidos graxos dos produtos derivados de ruminantes. Objetivo: avaliar o efeito da relação LA:LN em suplementos lipídicos sobre a cinética de biohidrogenação ruminal do LA e LN como também sobre a produção do ácido trans- vaccênico (VA), utilizando um sistema in vitro. Métodos: coletou-se fluido ruminal de um novilho fistulado, o qual foi diluído com tampão de incubação e, em seguida, incubado com 500 mg de pasto kikuyu (Cenchrus clandestinus) suplementado com 16,3 mg de diferentes misturas LA:LN (100:0, 75:25 , 50:50, 25:75 ou 0:100). As incubações foram desenvolvidas em triplicata, durante 0, 2, 4, 6, 8 ou 16 horas. Diferenças entre tratamentos foram avaliadas utilizando-se um delineamento inteiramente casualizado. Alternativamente, foram determinadas as mudanças em energia livre de Gibbs ( Δ Grxn) a 39 °C para as principais etapas da biohidrogenação do LA e LN, utilizando-se química computacional. Resultados: a substituição parcial de LA por LN diminuiu a concentração de VA e sua taxa de acumulação, como também aumentou a concentração de ácido esteárico e as taxas de transferência do LA para o ácido linoleico conjugado (CLA) e do CLA para VA. A conversão do CLA para VA ( Δ Grxn = -2,65 kJ/ mol) foi mais espontânea que a conversão do ácido trans-11, cis-15 octadecadienóico (TA) para VA ( Δ Grxn = -0,29 kJ/mol). Conclusões: a relação LA:LN em lipídeos pode modular a cinética de biohidrogenação (BH) do LA e LN e a produção de VA no rúmen.

El Freud cognitivo: Los conceptos de la Física en El Proyecto / Cognitive Freud: The concepts of Physics in The project

El Proyecto de Psicología para Neurólogos constituye el más enérgico intento de Freud de formular un modelo de funcionamiento psíquico en el marco de las Ciencias Naturales. Así, estudia la composición del sistema mental llegando a diferenciar la existencia de tres subsistemas neuronales y analiza los avatares de la cantidad Q, esencia de la dinámica psíquica y fundamento de la organización Yoica. El propósito de este trabajo es explicitar el uso de los conceptos provenientes de la Física de su época y la forma que tomaron en el Proyecto. Se presentan cuatro ejes: (1) La noción de sistema, estado y cambio de estado, para analizar las proposiciones metateóricas. (2) La sustentación dela dinámica psíquica en el primer y segundo principio de la Termodinámica. (3) El símil de las nociones electrodinámicas en el funcionamiento del aparato psíquico. (4) El estudio de las características ondulatorias como sustento del tercer subsistema neuronal del modelo.

The Project for a Scientific Psychology is Freud's most forceful attempt to formulate a model of psychic functioning within the framework of the natural sciences. In order to do this he defines the psychism as a system constituted by specifiable material particles, the neurons, particles subject to changes of state according to an operator of change of state conceived as an amount (Q) and on which the laws of Newton validly operate. In this way, he studies the composition of the mental system, differentiating the existence of three neuronal subsystems (Fi, Psi and Omega) and analyzing the avatars of the quantity Q as a state change operator, which is essentially the motor of the Psychicdynamics and foundation of the Ego organization organization, taking this organization as a particular state of the distribution of Q in the system. The purpose of this work is to make explicit the use of the concepts coming from the physics of that time and the form they took in the Project. This paper presents four axes: 1) The notion of system, state and change of state. Freud advocates for a Psychology defined as natural science as capable of representing phenomena as quantitatively determined states of specifiable material particles. The system is subject to state changes according toa physical and measurable change of state operator, which corresponds to the notion of quantity (Q). 2) The support of psychic dynamics in the first and second principles of thermodynamics. The tendency described in the Project as an impulse tothe discharge of the neuronal tension to zero, is heiress of a model constructed according to the first two principles of the thermodynamics. The notion of the general irreversibility of the psychic process, despite the mechanisms that retard, and even partially reverse the direction of the process, is an implicit idea on which all repetitive phenomena are based. The concept of facilitation itself involves the irreversibility of the process since it does not contemplate the possibility that mechanisms exist that may allow the reverse operation, except in the exceptional situation in which, for different reasons, the expected spontaneous sense is reversed, generating the process of regression. 3) The analogy of electrodynamics notions in the functioning of the psychic apparatus. Neurons, as conductors charged by a current flowing in a given direction, are also capable of storing a quantity of excitation, cathexis, neologism derived from the word cathode, used in physics. The idea of gradual local differences in potential is the only possible justification within the model for explaining psychic work as a product of the interrelationship between energy and work. Thus, it is difficult to say that when Freud developed his project he was not thinking of an electrodynamics model, it is difficult to imagine that he did not think of current (electron flow) when he spoke of current, or tha the did not think of physical resistances when he spoke of resistances, or that he did not think about tension when he described the storage of potential excitation, or else that he did not seek, finally, to formulate an Ohm law of neural function, when he spoke of their relations. 4) The study of the wave characteristics as the basis of the third neuronal subsystem of the model. The Project solves the problem of the quality by assigning to the currents in flow another property, the periodicity, independent of the quantity. This periodicity refers to frequency and frequency changes, which only in the Omega system become significant, because in the Psi system they do not exist, neither in Fi. These are, in Freud's words, monotonous, that is to say of uniform and constant frequency so as to give a unique tone.

Adsorption Isotherm and Thermodynamic Profile of Hexavalent Chromium onto Lumbang (Aleurites moluccana) Activated Carbon Chitosan Composite Crosslinked with Epichlorohydrin

Adsorption isotherm and thermodynamic profile of hexavalent chromium onto lumbang (Aleurites moluccana) activated carbon chitosan composite crosslinked with epichlorohydrin were studied. The optimum conditions were identified at pH 3, contact time of 75 min, adsorbent dose of 3 g/L, initial concentration of 60 ppm, and 30ºC temperature resulted to a removal efficiency of 93%. The composite has a round and elliptical adsorption sites, contains –OH and –NH2 functional groups, and has increased stability with epichlorohydrin crosslinking. The adsorption process is best characterized by the Langmuir isotherm suggesting a monolayer adsorption nature of Cr(VI). The adsorption kinetics obeyed the pseudo-second order model and the adsorption process is exothermic. The investigated adsorption phenomenon described a chemisorption process, with 21.32 kJ mol-1 mean free energy, due to the functional groups identified and the high porosity of the adsorbent surfaces.

Adsorption Property of Avilamycin on Silica Gel-based Absorbent / 中国药学杂志

OBJECTIVE: To investigate the kinetic and thermodynamic characteristics of adsorption of avilamycin on silica gel. METHODS: By measuring the adsorption of avilamycin on silica gel at different temperatures, the adsorption kinetics curves and adsorption isotherm were drawn, and the kinetics and thermodynamic parameters were studied. RESULTS: The adsorption of avilamycin on silica gel could be described well by Pseudo-second-order model. The adsorption process had feature of shrinking nonreactive core model, and the internal diffusion was the main rate-limiting step. The equilibrium adsorption data of avilamycin on silica gel fit the Langmuir isotherms well. The thermodynamic parameters were as follows:change in entropy (ΔS) was 108.115 2 J·mol-1·K-1, change in enthalpy (ΔH) was 24.654 6 J·mol-1, and changes in free energy (ΔG) were -8.752 9, -8.104 3, and -7.455 6 J·mol-1 at 309, 303 and 297 K, respectively. CONCLUSION: The RESULTS: of this study provide a theoretical basis for further study on the isolation and purification of high purity avilamycin by silica gel.

Thermodynamic studies of naringenin-isonicotinamide cocrystals / 药学学报

The purpose of this study was to investigate the thermodynamics of naringenin (NAR)-isonicotinamide (INT) cocrystal (stoichiometric ratio, 1∶2) formed in different solvents. The dissolution behavior of cocrystal was explored in the water. Solubility of NAR-INT cocrystals under various temperatures were measured, followed by fitting the complexation model to calculate the thermodynamic parameters solubility products (Ksp), complexation constants (K12) and Gibbs energy change (ΔG) of cocrystal during formation progress. Ternary phase diagrams (TPDs) of the NAR-INT-solvent systems under various temperatures were plotted. Based on the non-linear simulation, 1∶2 complexation model was well fitted to the NAR-INT cocrystal formation in ethanol, isopropanol and ethyl acetate, while no complexation model was more suitable for that in methanol. The cocrystallization reaction was exothermic and spontaneous (ΔG H S Ksp increased while K12 decreased when increasing temperature, suggesting that the two components could cocrystallize more easily at the lower temperature. In comparison to TPDs in other solvents, the area of homogeneous liquid phase in ethyl acetate was the smallest, indicating the easiest formation of NAR-INT cocrystal in ethyl acetate. The current study provides a theoretical foundation for preparation and optimization of scale-up NAR-INT cocrystals.

Physical and chemical quality, biodiversity, and thermodynamic prediction of adhesion of bacterial isolates from a water purification system: a case study

ABSTRACT The objective of this study was to evaluate the quality of water purification system and identify the bacteria this system, predict bacterial adherence according to the hydrophobicity of these microorganisms and of the polypropylene distribution loop for purified water. The assessment of drinking water that supplies the purification system allowed good-quality physical, chemical, and microbiological specifications. The physicochemical specifications of the distributed purified water were approved, but the heterotrophic bacteria count was higher than allowed (>2 log CFU mL-1).The sanitation of the storage tank with chlorine decreased the number of bacteria adhered to the surface (4.34 cycles log). By sequencing of the 16SrDNA genes, six species of bacteria were identified. The contact angle was determined and polypropylene surface and all bacteria were considered to be hydrophilic, and adhesion was thermodynamically unfavorable. This case study showed the importance of monitoring the water quality in the purified water systems and the importance of sanitization with chemical agents. The count of heterotrophic bacteria on the polypropylene surface was consistent with the predicted thermodynamics results because the number of adhered cells reached approximate values of 5 log CFU cm-2.

Formation mechanism of precipitation in Huanglian Jiedu Decoction based on molecular thermodynamic characteristics / 中草药

Objective To explore all sources of precipitation, parameters of interaction and binding abilities of different Chinese materia medica (CMM) combinations during the formation process of the precipitation in Huanglian Jiedu Decoction (HJD) using the thermodynamic method. The study was aim to reveal the mechanism of the formation of precipitation in CMM decoction. Methods First, the possible CMM combinations which had obvious precipitation phenomenon when combined were determined by the research on decomposed recipes. Then isothermal titration calorimetry (ITC) was used to determine the binding heat and thermodynamic parameters of binding reactions, thermodynamic parameters contents binding constant (Ka), dissociation constant (Kd), estimate of stoichiometric ratio (n), enthalpy change (ΔH), entropy change (ΔS), Gibbs free energy change (ΔG), these data were used to explain the differences in binding abilities between different CMM combinations. Results The original decomposed recipes experiment indicated the CMM combinations that could produce obvious precipitate when they were mixed were Scutellariae Radix-Coptidis Rhizoma and Scutellariae Radix-Phellodendri Chinensis Cortex. Precipitation amount of Scutellariae Radix-Coptidis Rhizoma was the most. There was no precipitate in Scutellariae Radix-Gardeniae Fructus, Coptidis Rhizoma-Phellodendri Chinensis Cortex, Coptidis Rhizoma-Gardeniae Fructus or Phellodendri Chinensis Cortex-Gardeniae Fructus. In ITC, the thermodynamic parameters of the three experience groups were the same, ΔH 0, ΔG |-TΔS|, indicating the three reactions were all enthalpy-driving reactions. The Ka of Scutellariae Radix decoction titrated Coptidis Rhizoma decoction was 1.283 × 104, Scutellariae Radix decoction titrated Phellodendri Chinensis Cortex deccotion was 4.680 × 103, Scutellariae Radix decoction titrated Gardeniae Fructus decoction was 1.973 × 103. The value decreased gradually. The binding heat of Scutellariae Radix and Gardeniae Fructus was much smaller than the binding heats of Scutellariae Radix and Coptidis Rhizoma, Scutellariae Radix and Phellodendri Chinensis Cortex. Conclusion During the formation process of the precipitation in HJD, the main source of acid-base complex-precipitation were Scutellariae Radix-Coptidis Rhizoma and Scutellariae Radix-Phellodendri Chinensis Cortex; Analysis of molecular thermodynamic indicates the binding energy of Scutellariae Radix and Coptidis Rhizoma was larger than that of Scutellariae Radix and Phellodendri Chinensis Cortex, compared with them, the binding energy of Scutellariae Radix and Gardeniae Fructus is tiny.

Adsorption Thermodynamics and Kinetics of Enramycin on XAD-16 Macroporous Resin / 中国药学杂志

OBJECTIVE: To investigate the adsorption thermodynamics and kinetics of enramycin on XAD-16 macroporous resin. METHODS: Series of static adsorption experiments were carried out. The adsorption equilibrium data were fitted to Langmuir and Freundlich isotherm equations, which could describe the adsorption behavior of enramycin on XAD-16 macroporous resin. The thermodynamic properties were described by thermodynamic parameters. Then, pseudo-first-order model and pseudo-second-order model were applied to describe the kinetics of adsorption process. RESULTS: The adsorption equilibrium data were agreed with Langmuir isotherm well. Thermodynamic analysis suggested ΔH<0, and ΔG<0, which indicated the adsortion procedure was a spontaneously exothermic reaction with entropy decrease. The adsorption of enramycin on XAD-16 macroporous resin could be described well by Pseudo-second-order model. CONCLUSION: The adsorption thermodynamics and kinetics of enramycin on XAD-16 macroporous resin can supply the theory for the separation and purification of enramycin on XAD-16 macroporous resin.