The Conditions Needed for a Buffer to Set the pH in a System

It is a known fact that buffer systems are widely used in industry and in diverse laboratories to maintain the pH of a system within desired limits, occasionally narrow. Hence, the aim of the present work is to study the buffer capacity and buffer efficacy in order to determine the useful conditions to impose the pH on a given system. This study is based on the electroneutrality and component balance equations for a mixture of protons polyreceptors. The added volume equations were established, V, for strong acids or bases, as well as the buffer capacity equations with dilution effect, β dil, and the buffer efficacy, ε, considering that the analyte contains a mixture of the species of the same polyacid system or of various polyacid systems. The ε index is introduced to define the performance of a buffer solution and to find out for certain, whether the buffer is adequate or not to set the pH of a system, given the proper conditions and characteristics

Transmission of Beauveria bassiana from male to female Aedes aegypti mosquitoes

<p>Abstract</p> <p>Background</p> <p>Resistance to chemical insecticides plus high morbidity rates have lead to rising interest in fungi as candidates for biocontrol agents of mosquito vectors. In most studies fungal infections have been induced by exposure of mosquitoes to various surfaces treated with conidia. In the present study eight Mexican strains of <it>Beauveria bassiana </it>were assessed against <it>Aedes aegypti </it>by direct exposure of females to 6 × 10⁸conidia ml ^-1on a filter paper, afterwards, the transmission of the least and most virulent isolates was evaluated by mating behavior from virgin, fungus-contaminated male to females, to examine this ethological pattern as a new approach to deliver conidia against the dengue vector.</p> <p>Methods</p> <p>In an exposure chamber with a filter paper impregnated with 6 × 10⁸conidia ml ^-1of the least and most virulent strains of <it>B. bassiana</it>, 6-8 day old males of <it>A. aegypti </it>were exposed for 48 hours, and then transferred individually (each one was a replicate) to another chamber and confined with twenty healthy females of the same age. Clean males were used in controls. Survival, infection by true mating (insemination) or by mating attempts (no insemination) and fecundity were daily registered until the death of last female. Data analysis was conducted with proc glm for unbalanced experiments and means were separated with the Ryan test with SAS.</p> <p>Results</p> <p>All strains were highly virulent with LT₅₀ranging from 2.70 (± 0.29) to 5.33 (± 0.53) days. However the most (Bb-CBG2) and least virulent (Bb-CBG4) isolates were also transmitted by mating behavior; both killed 78-90% of females in 15 days after being confined with males that had previously been exposed for 48 hours to fungi. Of these mortality rates, 23 and 38% respectively, were infections acquired by copulations where insemination occurred. The LT₅₀for sexually-infected females were 7.92 (± 0.46) and 8.82 (± 0.45) days for both strains, while the one in control was 13.92 (± 0.58). Likewise, fecundity decreased by 95% and 60% for both Bb-CBG2 and Bb-CBG4 isolates in comparison with control. The role of mating attempts in this delivery procedure of <it>B. bassiana </it>is discussed.</p> <p>Conclusions</p> <p>This is the first report about transmission of <it>B. bassiana </it>by mating behavior from virgin, fungus-contaminated males to females in <it>A. aegypti</it>. Fungal infections acquired by this route (autodissemination) infringed high mortality rates (90%) in mated or approached females. However, prior to releasing virgin, fungus-contaminated males to spread <it>B. basasiana </it>among females of <it>A. aegypti</it>, this novel alternative needs further investigations.</p

Alkaline pretreatment of Mexican pine residues for bioethanol production

The locally sourced residue samples of Pinus arizonica, Pinus cooperi, and Pinus durangensis from the state of Durango in Mexico were analyzed for optimal yield of ethanol production. The samples were mixed at an equal proportion using a particle size of 0.59 mm. Each individual mixture was pretreated with either NaOH or Ca (OH)2 (at 0.5, 1.0 and 1.5% w/v) for periods of 30, 60, and 90 min at 60, 90, and 120°C. The pretreated blending was subjected to enzymatic hydrolysis for 130 h at 80 rpm and 50°C with an enzymatic load of 25 filter paper units (FPU) and 50 IU β-glucosidase per gramme of cellulose to obtain a maximum yield of reducing sugars (RS) with NaOH subject at 120°C for 90 min. The results show that the hydrolysis yield depends on temperature and alkali concentration particularly (NaOH), which increased from 2.0 to 3.5% w/v. The best yield of glucose (41.33% w/w) was obtained using a pretreatment of 2.5% NaOH for 90 min, 120°C, and a hydrolysis residence time of 130 h. The removal of lignin and hemicellulose acetylation was observed to have influence on the enzymatic digestibility of cellulose. This process could theoretically produce a maximum yield of 90.19% of ethanol / substrate (glucose) and about 80 L of bioethanol per dry ton of woody biomass from pine residues.Keywords: Lignocellulosic biomass, alkaline pretreatment, enzymatic hydrolysis, fermentable sugars, fermentationAfrican Journal of Biotechnology Vol. 12(31), pp. 4956-496

Capacidad antioxidante total de la dieta vs. balance redox

&nbsp; La asociación inversa que existe entre las dietas ricas en frutas y hortalizas y la aparición de enfermedades crónicas no transmisibles sigue acaparando importancia a nivel mundial en las líneas de investigación de la nutrición y la dietética. Es por eso que incluir en las estimaciones dietéticas, los aspectos relacionados con la capacidad antioxidante que aportan los alimentos y evaluar la alimentación ya no solo desde la óptica de los indicadores clásicos de calidad, constituye un enfoque novedoso y que resulta importante por su implicación en el estrés oxidativo en la etiología de disímiles enfermedades. Este trabajo presenta los principales aspectos sobre la relación entre la dieta y el balance de las reacciones redox en el organismo, sin pretender abordarlos de forma absoluta e integral. &nbsp; Palabras clave: Capacidad antioxidante, dieta, balance redox, estrés oxidativo. &nbsp; Abstract The inverse association that exists between diets rich in fruits and vegetables and the appearance of chronic non-communicable diseases continues to gain importance worldwide in the research lines of nutrition and dietetics. That is why including in the dietary estimates, the aspects related to the antioxidant capacity provided by foods and evaluating the diet not only from the point of view of the classic quality indicators, constitutes a novel approach that is important due to its involvement in oxidative stress in the etiology of dissimilar diseases. This work presents the main aspects of the relationship between diet and the balance of redox reactions in the body, without attempting to address them in an absolute and comprehensive way. &nbsp; Keywords: Antioxidant capacity, diet, redox balance, oxidative stress

The orosomucoid 1 protein (α1 acid glycoprotein) is overexpressed in odontogenic myxoma

Odontogenic myxoma (OM) is a benign, but locally invasive, neoplasm occurring in the jaws. However, the molecules implicated in its development are unknown. OM as well as Dental Follicle (DF), an odontogenic tissue surrounding the enamel organ, is derived from ectomesenchymal/mesencyhmal elements. To identify some protein that could participate in the development of this neoplasm, total proteins from OM were separated by two-dimensional electrophoresis and the profiles were compared with those obtained from DF, used as a control

Virucidal and Synergistic Activity of Polyphenol-Rich Extracts of Seaweeds against Measles Virus

Although preventable by vaccination, Measles still causes thousands of deaths among young children worldwide. The discovery of new antivirals is a good approach to control new outbreaks that cause such death. In this study, we tested the antiviral activity against Measles virus (MeV) of Polyphenol-rich extracts (PPs) coming from five seaweeds collected and cultivated in Mexico. An MTT assay was performed to determine cytotoxicity effect, and antiviral activity was measured by syncytia reduction assay and confirmed by qPCR. PPs from Ecklonia arborea (formerly Eisenia arborea, Phaeophyceae) and Solieria filiformis (Rhodophyta) showed the highest Selectivity Index (SI), \u3e3750 and \u3e576.9 respectively. Both PPs extracts were selected to the subsequent experiments owing to their high efficacy and low cytotoxicity compared with ribavirin (SI of 11.57). The combinational effect of PPs with sulphated polysaccharides (SPs) and ribavirin were calculated by using Compusyn software. Synergistic activity was observed by combining both PPs with low concentrations of Solieria filiformis SPs (0.01 µg/mL). The antiviral activity of the best combinations was confirmed by qPCR. Virucidal assay, time of addition, and viral penetration evaluations suggested that PPs act mainly by inactivating the viral particle. To our knowledge, this is the first report of the virucidal effect of Polyphenol-rich extracts of seaweeds

Extractos de neem en el comportamiento de Aphis nerii y la transmisión del virus de la mancha anular del papayo

The effect of neem extracts on feeding behavior of Aphis nerii, as well as Papaya Ringspot Virus (PRSV-p) transmission, was determined. We evaluated papaya seedlings sprayed under laboratory conditions with a 10% aqueous extract of unpeeled neem seed and with a water control. Two time periods, exploratory (0 to 3 min) and feeding (&gt;3 to 20 min), were used to evaluate aphid feeding behavior. Aphid mortality was determined 24 h after spraying. Viral transmission was measured by ELISA tests. No significant differences (p &gt; 0.05) were obtained in the exploratory feeding behavior. However, significantly more aphids (p &lt; 0.05) stopped feeding on neemsprayed plants from the &gt;3 to 20 min period. Also, higher (p &lt; 0.05) aphid mortality (37% vs. 10%) was found in neem-sprayed plants. However, no significant differences (p &gt; 0.05) were found in PRSV-p transmission, thus indicating that neem seed aqueous extracts did not prevent viral transmission.Se determinó el efecto de extractos de neem en el comportamiento de alimentación y la transmisión del Virus de la Mancha Anular del Papayo (PRSV-p) por Aphis nerii. Se evaluó un extracto acuoso al 10% de semillas de neem sin escarificar, y un testigo con agua, asperjados en plantas de papayo en el laboratorio. El comportamiento de alimentación del áfido se estudió en dos fases: exploratoria (0 hasta 3 min) y de alimentación (&gt;3 hasta 20 min). Se determinó la mortalidad de áfidos a las 24 h. El análisis de la transmisión del virus se realizó con base en pruebas de ELISA. No se detectaron diferencias significativas (p &gt; 0.05) en cuanto al comportamiento de alimentación para la fase exploratoria, lo que indica que el neem no afecta la búsqueda y el probado inicial del áfido sobre la planta. En cambio, un número significativamente mayor de áfidos (p &lt; 0.05) dejó de alimentarse en la fase &gt;3 hasta 20 min. Además, la mortalidad de áfidos es mayor (p &lt; 0.05) en el tratamiento con plantas asperjadas con neem (37% vs. 10%). No se encontraron diferencias significativas (p &gt; 0.05) en la transmisión del PRSV-p por Aphis nerii, lo que indica que los extractos acuosos de semillas de neem no impiden la transmisión del virus

Vivienda Emergente

El trabajo que se desarrolló durante este PAP está enfocado en la vivienda emergente, específicamente en el caso del señor Maximiliano, quien habita en la comunidad de Santa Maria Tequepexpan y quien vive en una situación precaria. Por lo cual se tomó como modelo y usuario principal, para generar un prototipo de vivienda emergente que sea funcional y responda a las necesidades básicas que requiere nuestro usuario, así como gran parte de la población en condiciones similares o peores. Los objetivos previstos fueron la planificación e implementación con acompañamiento en la construcción de la vivienda del usuario, sirviendonos de este modelo como taller paracompartir los conocimientos en conjunto con la comunidad de los alrededores, la intención es mejorar o replicar el modelo de la vivienda emergente

Esquemas de contratos agrícolas para la producción de Agave Tequilana Weber en la región de Tequila, Jalisco.

The production of Agave tequilana Weber var. azul suffers cyclical crises derived from the fluctuations of agave prices and periods of oversupply and scarcity of the product in the market. The establishment of production and buying and selling contracts between agaveros (agave producers) and tequila industries has been one of the alternatives proposed to reduce the effects of these cyclic crises and stabilize the agave market. The objective of this study was to identify the types of contracting for the production and commercialization of Agave tequilana in the productive chain of agave-tequila in the municipality of Tequila, Jalisco. A sample of 50 agave producers selected randomly were surveyed, who produced agave under three types of contracts: a) Leasing; b) Share-cropping; and c) Tenant farming (métayage). Contract by leasing is the most frequent plan and has displaced the informal plans of share-cropping and tenant farming. The lessors carry out agave cultivation mainly as monoculture, and the sharecroppers and tenant farmers (metayer) in polyculture. The common factor between share-cropping and tenant farming is that the owners have access to their plots, and the main difference lies in the form of appropriation of the agave harvest.La producción de Agave tequilana Weber var. azul sufre de crisis cíclicas derivadas de las fluctuaciones de los precios de agave y períodos de sobreoferta y escasez del producto en el mercado. El establecimiento de contratos de producción y compraventa entre agaveros e industrias tequileras ha sido una de las alternativas propuestas para reducir los efectos de estas crisis cíclicas y estabilizar el mercado del agave. El objetivo del presente estudio fue identificar los tipos de contratación para la producción y comercialización de Agave tequilana en la cadena productiva de agave-tequila del municipio de Tequila, Jalisco. Se encuestó a una muestra de 50 productores de agave seleccionados al azar, quienes producen agave bajo tres tipos de contratos: a)Arrendamiento; b) Aparcería; y c) Mediería. El contrato por arrendamiento es el más frecuente y ha desplazado a los esquemas informales de aparcería y mediería. Los arrendadores realizan las labores del agave principalmente en monocultivo y los aparceros y medieros en policultivo. El factor común entre la aparcería y la mediería es que los propietarios tienen acceso a sus predios y la diferencia principal radica en la forma de apropiación de la cosecha de agave

Analysis of the pathogenic potential of nosocomial Pseudomonas putida strains

The Supplementary Material for this article can be found online at: http://journal.frontiersin.org/article/10.3389/fmicb.2015.00871Pseudomonas putida strains are ubiquitous in soil and water but have also been reported as opportunistic human pathogens capable of causing nosocomial infections. In this study we describe the multilocus sequence typing of four P. putida strains (HB13667, HB8234, HB4184, and HB3267) isolated from in-patients at the Besançon Hospital (France). The four isolates (in particular HB3267) were resistant to a number of antibiotics. The pathogenicity and virulence potential of the strains was tested ex vivo and in vivo using different biological models: human tissue culture, mammalian tissues, and insect larvae. Our results showed a significant variability in the ability of the four strains to damage the host; HB13667 did not exhibit any pathogenic traits, HB4184 caused damage only ex vivo in human tissue cultures, and HB8234 had a deleterious effect in tissue culture and in vivo on rat skin, but not in insect larvae. Interestingly, strain HB3267 caused damage in all the model systems studied. The putative evolution of these strains in medical environments is discussed.Work in this study was supported by the ERANET Pathogenomics Program through the ADHERS-Signature Project (reference: BIO2008-04419-E)Peer reviewe