Prediction of band edge potentials and reaction products in photocatalytic copper and iron sulfides.

The prediction of band edge potentials in photocatalytic materials is an important but challenging task. In contrast, bandgaps can be easily determined through absorption spectra. Here, we present two simple theoretical approaches for the determination of band edge potentials which are based on the electron negativity and work function of each constituent atom. We use these approaches to determine band edge potentials in semiconducting metallic oxides and sulfides, such as titanium dioxide (TiO2), chalcopyrite (CuFeS2), pyrite (FeS2), covellite (CuS), and chalcocite (Cu2S) with respect to an absolute scale (eV) and an electrochemical scale (V). Until now, there is little information on iron and copper sulfides referring to these thermodynamic parameters. TiO2 (Titania p25) was used as reference semiconductor to validate the calculation procedures using experimental values by X-ray diffraction analysis (XRD), diffuse reflectance spectrometry (DRS), and electron paramagnetic resonance spectroscopy (EPR). The production of key chemical species such as reactive oxygen species (ROS) and reactive sulfur species (RSS) has been theoretically and experimentally determined by EPR.

Clinical Manifestations, Mutational Analysis, and Immunological Phenotype in Patients with RAG1/2 Mutations: First Cases Series from Mexico and Description of Two Novel Mutations.

Mutations in recombinase activating genes 1 and 2 (RAG1/2) result in human severe combined immunodeficiency (SCID). The products of these genes are essential for V(D)J rearrangement of the antigen receptors during lymphocyte development. Mutations resulting in null-recombination activity in RAG1 or RAG2 are associated with the most severe clinical and immunological phenotypes, whereas patients with hypomorphic mutations may develop leaky SCID, including Omenn syndrome (OS). A group of previously unrecognized clinical phenotypes associated with granulomata and/or autoimmunity have been described as a consequence of hypomorphic mutations. Here, we present six patients from unrelated families with missense variants in RAG1 or RAG2. Phenotypes observed in these patients ranged from OS to severe mycobacterial infections and granulomatous disease. Moreover, we report the first evidence of two variants that had not been associated with immunodeficiency. This study represents the first case series of RAG1- or RAG2-deficient patients from Mexico and Latin America.

CiPerGenesis, A Mutagenesis Approach that Produces Small Libraries of Circularly Permuted Proteins Randomly Opened at a Focused Region: Testing on the Green Fluorescent Protein.

Circularly permuted proteins (cpPs) represent a novel type of mutant proteins with original termini that are covalently linked through a peptide connector and opened at any other place of the polypeptide backbone to create new ends. cpPs are finding wide applications in biotechnology because their properties may be quite different from those of the parental protein. However, the actual challenge for the creation of successful cpPs is to identify those peptide bonds that can be broken to create new termini and ensure functional and well-folded cpPs. Herein, we describe CiPerGenesis, a combinatorial mutagenesis approach that uses two oligonucleotide libraries to amplify a circularized gene by PCR, starting and ending from a focused target region. This approach creates small libraries of circularly permuted genes that are easily cloned in the correct direction and frame using two different restriction sites encoded in the oligonucleotides. Once expressed, the protein libraries exhibit a unique sequence diversity, comprising cpPs that exhibit ordinary breakpoints between adjacent amino acids localized at the target region as well as cpPs with new termini containing user-defined truncations and repeats of some amino acids. CiPerGenesis was tested at the lid region G134-H148 of green fluorescent protein (GFP), revealing that the most fluorescent variants were those starting at Leu141 and ending at amino acids Tyr145, Tyr143, Glu142, Leu141, Lys140, and H139. Purification and biochemical characterization of some variants suggested a differential expression, solubility and maturation extent of the mutant proteins as the likely cause for the variability in fluorescence intensity observed in colonies.

Simultaneous determination of albendazole and praziquantel by second derivative spectrophotometry and multivariated calibration methods in veterinary pharmaceutical formulation.

The simultaneous determination of albendazole (ABZ) and praziquantel (PZQ) was performed by different mathematical approaches: second derivative spectrophotometry (SDS), classical least squares, regression of partial least squares and principal components regression based on spectral data of drugs dissolved in methanol-hydrochloric acid solution. The detection limits for multivariate calibrations were determined by creating a surrogate variable signal. SDS presented the best analytical features. The recoveries of ABZ and PZQ from the synthetic samples were near to 100 +/- 5%. The methods were applied in veterinary pharmaceutical formulation whose mass ratio ABZ:PZQ is 10:1; the results obtained were according to nominal content.

In field arsenic removal from natural water by zero-valent iron assisted by solar radiation.

An in situ arsenic removal method applicable to highly contaminated water is presented. The method is based in the use of steel wool, lemon juice and solar radiation. The method was evaluated using water from the Camarones River, Atacama Desert in northern Chile, in which the arsenic concentration ranges between 1000 and 1300 microg L(-1). Response surface method analysis was used to optimize the amount of zero-valent iron (steel wool) and the citrate concentration (lemon juice) to be used. The optimal conditions when using solar radiation to remove arsenic from natural water from the Camarones river are: 1.3 g L(-1) of steel wool and one drop (ca. 0.04 mL) of lemon juice. Under these conditions, removal percentages are higher than 99.5% and the final arsenic concentration is below 10 microg L(-1). This highly effective arsenic removal method is easy to use and inexpensive to implement.

[Community-acquired pneumonia caused by Streptococcus pyogenes: report of one case]. / Neumonía grave por Streptococcus pyogenes: Reporte de un caso.

During the past two decades there has been a resurgence of invasive group A streptococcal (GAS) infection, specially pneumonia and bacteremia. We report a 35 year-old female previously subjected to a thyroidectomy for a thyroid cancer, that five days after operation, presented with a severe community-acquired pneumonia caused by Streptococcus pyogenes (Lancefield Group A Streptococcus) that was complicated by acute respiratory failure and septic shock. She was treated with a combination of 3 g/day of cefotaxime and 1.8 g/day of clindamycin with a good clinical response and discharged from the hospital in good conditions. Although this microorganism is an uncommon cause of community-acquired pneumonia, previously healthy individuals may be infected and the clinical course may be fulminant. Patients with invasive GAS infection admitted to ICU have a high mortality rate. Treatment of choice of Group A streptococcal infection is penicillin. However, clindamycin should be added in severe infections .

The genome project of Taenia solium.

We have constituted a consortium of key laboratories at the National Autonomous University of Mexico to carry out a genomic project for Taenia solium. This project will provide powerful resources for the study of taeniasis/cysticercosis, and, in conjunction with the Echinococcus granulosus and Echinococcus multilocularis genome project of expressed sequence tags (ESTs), will mark the advent of genomics for cestode parasites. Our project is planned in two consecutive stages. The first stage is being carried out to determine some basic parameters of the T. solium genome. Afterwards, we will evaluate the best strategy for the second stage, a full blown genome project. We have estimated the T. solium genome size by two different approaches: cytofluorometry on isolated cyton nuclei, as well as a probabilistic calculation based on approximately 2000 sequenced genomic clones, approximately 3000 ESTs, resulting in size estimates of 270 and 251 Mb, respectively. In terms of sequencing, our goal for the first stage is to characterize several thousand EST's (from adult worm and cysticerci cDNA libraries) and genomic clones. Results obtained so far from about 16,000 sequenced ESTs from the adult stage, show that only about 40% of the T. solium coding sequences have a previously sequenced homologue. Many of the best hits are found with mammalian genes, especially with humans. However, 1.5% of the hits lack homologues in humans, making these genes immediate candidates for investigation on pharmaco-therapy, diagnostics and vaccination. Most T. solium ESTs are related to gene regulation, and signal transduction. Other important functions are housekeeping, metabolism, cell division, cytoskeleton, proteases, vacuolar transport, hormone response, and extracellular matrix activities. Preliminary results also suggest that the genome of T. solium is not highly repetitive.

Ileal amino acid digestibility and performance of pigs fed grain sorghum-based diets supplemented with phytase

Se realizaron dos experimentos para determinar el efecto de la adición de fitasa a dietas sorgo-pasta de soya en la digestibilidad ileal aparente (DIA) de aminoácidos (AA) y el comportamiento de cerdos en crecimiento. En un experimento, seis cerdos (peso promedio inicial 86,1kg) adaptados con una cánula simple tipo T en íleon terminal, fueron alimentados con tres dietas de acuerdo con un cuadro Latino repetido 3x3. La Dieta 1 fue la dieta base sorgo-pasta de soya; las Dietas 2 y 3 fueron la Dieta 1 adicionada con 500 y 1000 unidades de actividad de fitasa (FTU)/kg alimento, respectivamente. No se encontró efecto de la adición de fitasa en la DIA de AA (P>0,10). La DIA de arginina fue la más elevada y la de treonina la más baja. En otro experimento se distribuyeron aleatoriamente 28 cerdos (peso promedio inicial 22,9kg) en cuatro dietas (siete repeticiones/tratamiento) de acuerdo con un diseño de bloques completos al azar. Las dietas fueron: 1) dieta base sorgo-pasta de soya y 0,67% lisina digestible en íleon; 2) dieta base +350FTU/kg de alimento; 3) dieta base +700FTU; 4) dieta base +1050FTU. La dieta base cubría 100% el requerimiento de P disponible para cerdos de 20-50kg. Los análisis de regresión no mostraron efecto de la adición de fitasa en la ganancia diaria de peso (P=0,93); consumo de alimento, lisina y treonina (P=0,37); ni en la conversión alimenticia (P=0,54). Los cerdos alimentados con dieta base tendieron a tener una mayor ganancia de peso que los que recibieron la dieta 2 (P=0,09) o la dieta 3 (P=0,11). Los resultados indican que la fitasa no afecta el suministro de AA digestibles o, como consecuencia, el comportamiento de cerdos alimentados con dietas sorgo-pasta de soya.

Two experiments were conducted to determine the effect of phytase supplementation to sorghum-soybean meal diets on the apparent ileal digestibility (AID) of amino acids (AA) and performance of growing pigs. In one experiment, six pigs (average initial BW 86.1kg) fitted with a simple T-cannula at the distal ileum, were fed three diets in a repeated 3x3 Latin square design. Diet 1 was the basal sorghum-soybean meal diet. Diets 2 and 3 were the basal diet supplemented with phytase at 500 and 1000 units of phytase activity (FTU/kg diet), respectively. There was no effect of phytase supplementation on the AID of AA (P>0.10). Arginine AID was highest and threonine AID was lowest. In the second experiment, 28 pigs (average initial BW 22.9kg) were allotted to four diets (seven replicates/treatment) in a randomized complete block design. Diets were: 1) sorghum-soybean meal, basal diet, 0.67% apparent ileal digestible lysine; 2) basal diet +350FTU/kg diet; 3) basal +700FTU; 4) basal +1050FTU. The basal diet contained 100% of the available P requirement for pigs 20-50kg. Linear regression analyses showed no effect of phytase supplementation on average daily gain (ADG; P=0.93), feed (P=0.37), lysine (P=0.37) and threonine (P=0.37) intakes, or feed conversion (P=0.54). Pigs fed the basal diet tended to have higher ADG than those fed diet 2 (P=0.09) or diet 3 (P=0.11). Results indicate that phytase supplementation does not affect the supply of digestible AA or, as a consequence, the performance of pigs fed sorghum-soybean meal diets.

Realizaram-se dois experimentos para determinar o efeito da adição de fitasa a dietas sorgo-pasta de soja na digestibilidade ileal aparente (DIA) de aminoácidos (AA) e o comportamento de cerdos em crescimento. Em um experimento, seis cerdos (peso médio inicial 86,1kg) adaptados com uma cânula simples tipo T em íleon terminal, foram alimentados com três dietas de acordo com um quadro Latino repetido 3x3. A Dieta 1 foi a dieta base sorgo-pasta de soja; as Dietas 2 e 3 foram a Dieta 1 adicionada com 500 e 1000 unidades de atividade de fitasa (FTU)/kg alimento, respectivamente. Não encontrou-se efeito da adição de fitasa na DIA de AA (P>0,10). A DIA de arginina foi a mais elevada e a de treonina a mais baixa. Em outro experimento se distribuiram aleatoriamente 28 cerdos (peso médio inicial 22,9kg) em quatro dietas (sete repetições/tratamento) de acordo com um desenho de blocos completos ao azar. As dietas foram: 1) dieta base sorgo-pasta de soja e 0,67% lisina digestiva em íleon; 2) dieta base +350FTU/kg de alimento; 3) dieta base +700FTU; 4) dieta base +1050FTU. A dieta base cobria 100% o requerimento de P disponível para cerdos de 20-50kg. As análises de regressão não mostraram efeito da adição de fitasa na ganância diária de peso (P=0,93); consumo de alimento, lisina e treonina (P=0,37); nem na conversão alimentícia (P=0,54). Os cerdos alimentados com dieta base tenderam a ter uma maior ganância de peso que os que receberam a dieta 2 (P=0,09) ou a dieta 3 (P=0,11). Os resultados indicam que a fitasa não afeta o subministro de AA digestivos ou, como conseqüência, o comportamento de cerdos alimentados com dietas sorgo-pasta de soja.