benjamin guzman

espanolCuando se altera el cerebro humano en desarrollo y se produce una disfuncion cognitiva, neurologica o psiquiatrica, se originan los Trastornos del Neurodesarrollo, teniendo el Trastorno del Espectro Autista (TEA) un lugar destacado. La prevalencia del TEA es de 1 cada 68 ninos, aunque se discuten las variaciones dependiendo la region y la forma de medicion. Esta revision comprende, en parte, las principales caracteristicas y problematicas alrededor del desarrollo biologico del cerebro desde el punto de vista genetico. Sin embargo, es destacable el factor ambiental incidente de los genes, que tiene influencia pequena a moderada, aunque a la hora de marcar un desencadenante genetico o ambiental clave, existe una gran heterogeneidad etiologica del TEA. Por otra parte, en este trabajo se abarcaran cambios estructurales y funcionales en el sistema nervioso central, analizando las caracteristicas neurofisiologicas y morfologicas que intervienen en el trastorno. Asi mismo, se analiz...

Ticket vending machine (TVM) and automated fare collection system–Point of sale (AFCS-POS) are two new technologies in the Philippines’ train ticketing system. After a year of implementation for the newly deployed ticketing system in Metro Rail Transit (MRT), research shows that there have been no usability evaluation on the new system to evaluate for potential issues and user interface problems. Based on observation and interviews, about 17.5% of train passengers are still having difficulty with using the ticket vending machine and is repulsive to use it for buying ticket thereby increasing the workload for AFCS-POS machine specialists. The study focuses on three aspects of the TVM and AFCS-POS usability measures, (1) effectiveness, (2) efficiency and (3) satisfaction, as defined by ISO 9241-11. Usability analysis showed that effectiveness of the two systems was above average. Efficiency of AFCS-POS is significantly higher than TVM. Some of the first time TVM users were having a di...

Gemeinsames, asymmetrisches Kontrollverfahren fur die primare Frequenzregelung (PFR) in Kombikraftwerken (Gas- und Dampf-Kraftwerken) fur Stromerzeugung, mit wenigstens einer Gasturbine und einer Dampfturbine, wobei die Dampfturbine des kombinierten Arbeitsprozesses sich an der primaren Frequenzregelung beteiligt, und zwar uber Speicherung von Rotationsenergie durch Drosselung der Regelventile mit z. B. dem Verfahren des Patents USA 6.609.361, und wobei die Abhitz-Kessel und dementsprechend die Dampfturbine des kombinierten Prozesses mit drei verschiedenen Dampfdrucken arbeitet (Hochdruckdampf, Mitteldruckdampf und Niederdruckdampf) und einen Bypass mit einem Kontroll-Bypassventil vom Hochdruckkreislauf zum Mitteldruckkreislauf aufweist, wodurch die Gasturbinen die erzeugte Nutzleistung steigern und gleichzeitig ihre fur die PFR bestimmte Rotationsenergiereserve reduzieren. Die Dampfturbine verfugt aber uber eine zusatzliche Rotationsenergiereserve fur den PFR-Prozess, um das in den...

Genelba power plant has been offering primary frequency regulation (PFR) to the highly competitive Argentina electricity market without sacrificing gas turbine capacity. During two years of operation this innovative approach, entirely realised by plant staff, has proved effective and lucrative.

To gain insight into early reproductive processes we have prospectively designed ovum donation protocols to elucidate several phenomena relating to embryo implantation and pregnancy sustenance. Artificial endometrial cycles with variable follicular phases were induced in 60 recipients by sequential estrogen and progesterone. A total of 964 oocytes were retrieved throughout 43 ovum donation attempts, for an average of 22.4 (range, 16-41) eggs/retrieval. The overall delivery rate per egg retrieval (donors and recipients combined) was 72.1% (31 of 43). The shortest estrogen stimulation (short follicular phase) resulting in ongoing pregnancies was 5 days in duration, while the longest (long follicular phase) was 35 days in duration before progesterone initiation. Utilization of variable length follicular phases, artificially extended the stage of endometrial receptivity to over 4 weeks. To assess the window of implantation, same age embryos were transferred onto endometrium of different maturational stages. Pregnancies were documented with embryo transfers between luteal day 1 (day 15) to luteal day 6 (day 20), extending the window of implantation in the human to at least 6 consecutive days. To evaluate the relative contribution of oocyte quality and endometrial receptivity to pregnancy outcome, common source ova were transferred onto endometrium with variable hormonal exposure. Despite the drastically different follicular phase estradiol levels and periods of exposure, similar delivery rates were attained in donor cycles (29.4%) and recipient cycles during short follicular phases (29.6%). Slightly higher delivery rates (39.4%) were observed with long follicular phases. The comparable pregnancy rates in donors and recipients are attributed to the common source oocytes regardless of endometrial stimulation.

Several types of HIV-related oral mucosal conditions have been reported to occur during the course of HIV disease progression. Of these, few may be manifested as 'white' lesions and many are noticeable to the patient. This paper examines the relationships between social, behavioral and medical aspects of HIV infection and reporting an occurrence of oral white patches (OWP) by HIV-infected patients. The subjects are participants in all three interviews in the HIV Cost and Services Utilization Study (HCSUS). The subjects were selected using a three-stage probability sampling design. The multivariate analysis is based on 2109 subjects with nonmissing binary outcome variable for all three waves representing a national sample of 214 000 individuals. The multivariate model was fitted using generalized estimating equations (GEE) by implementing the XTGEE command in STATA. We estimate that 75 000 persons (35%) reported at least one incident of OWP, of these 14 000 reported having OWP during all three interviews, and that the rate of reporting declined over the three HCSUS waves. The multivariate analysis showed seven variables that were significant predictors of at least one report of OWP. Compared with persons on HAART therapy, patients on other regimens or taking no antiviral medications were 23-46% more likely to report an incident of OWP. Compared with whites, African Americans were 32% less likely to report OWP, while current smokers were 62% more likely than nonsmokers. Being diagnosed with AIDS and having CD4 counts less than 500 significantly increased the likelihood of reporting OWP.

O6-Methylguanine-DNA methyltransferase (O6-MT) is a DNA repair protein that reverses alkylation damage at the O6 position of guanine. In the process, O6-MT undergoes suicide inactivation. To determine if this enzyme might be regulated by pregnancy-associated hormones we measured changes in the level of O6-MT in isolated mouse mammary epithelial cell homogenates during different reproductive states. These were pregnancy, ectopic pituitary transplantation, proestrus/estrus and diestrus. O6-MT levels were found to be similar in mice in proestrus/estrus (0.95 fmol/micrograms DNA) as compared to diestrus (0.94 fmol/micrograms DNA) and also mixed populations of virgin mice (1.09 fmol/micrograms DNA). A mean for all virgin mice (0.97 fmol/micrograms DNA) was used as a comparative index. O6-MT decreased 2-fold during pregnancy in mammary epithelial cells to a mean value of 0.45 fmol/micrograms DNA (P less than 0.05). A smaller decrease (0.65 fmol/micrograms DNA; P less than 0.01) in mammary epithelial cells was found at 3 weeks following pituitary isograft. The repair capacity of mammary epithelial cells to liver was compared by measurements made in liver homogenates from the same mice and are approximately 3-fold higher in liver from virgin mice (3.2 fmol/micrograms DNA) than mammary gland. Liver levels of O6-MT increased in pregnant (5.3 fmol/micrograms DNA) and pituitary transplanted (3.9 fmol/micrograms DNA) mice, and were 5- and 4-fold higher than the concentration in virgin mammary epithelial cells respectively.

Technetium-99m-mercaptoacetyltriglycine (99mTc-MAG3) is a radiopharmaceutical for tubular function and can be prepared with 99m-technetium and the ligand Bz-MAG3 (Instituto Nacional de Investigaciones Nucleares, Mexico City). No radiopharmacokinetic parameters have been found for the healthy adult Mexican population with 99mTc-MAG3, prepared with the nationally produced or imported Bz-MAG3 kit. The radiopharmacokinetic parameters and the clearance of 99mTc-MAG3 in seven healthy Mexican volunteers were determined by the single- and multi-sample methods. Computer programs were used for the calculations. Using several plasma samples from 0-43 min and the BIEXP program, it was shown that 99mTc-MAG3 follows a two-compartment model of distribution, with an apparent volume in the central compartment Vdcc = 3.8 + 0.7 l, a volume of distribution at steady state Vdss = 6.7 + 1.0 l, T1/2 alpha = 0.07 + 0.02 h-1, T1/2 beta = 0.49 + 0.15 h-1, mean residence time MRT = 0.60 + 0.17 h and clearance = 208 + 57 (ml/min)/1.73 m2. In comparison, the clearance value with a single sample drawn 43 min post-injection and calculated with Tauxe's formula was 193 +/- 59 (ml/min)/m2. The 15 ml difference between the two methods is neither statistically different (p = 0.11) nor important for routine clinical studies. The single-sample method is recommended because it is reliable and can be done at the same time that the dynamic renal scan is acquired. Estimated absorbed radiation dose was calculated for several organs.