A Tool for the Automatic Generation and Analysis of Regular Analog Layout Modules

This paper describes the characteristics of a new CAD tool that enables the creation of layout libraries of selected analog modules. This Analog Modules Generator (AMG) automatically creates multiple layout versions of two commonly used analog structures: the differential pair and arrays of series-connected or stacked devices, for the subsequent generation of layout libraries. Based on the number of devices and rows defined by the user for the layout implementation, the tool validates all possible implementations, which are later saved in a database with their corresponding characteristics, such as area and parasitics information. Additionally, an extraction process can be optionally executed over all the layout views saved in the database. The AMG generates several reports with all the characteristics of the implemented layouts, including area and parasitic components, facilitating further statistical processing. We describe the features and capabilities of the proposed AMG tool, and several test cases are presented. Results show that optimal layout implementations can be achieved by layout and circuit designers in a reduced amount of time

Analysis of the Implications of Stacked Devices in Nano-Scale Technologies for Analog Applications

In this work, a methodology to assess the implications on the performance of analog circuits due to the use of stacked devices in current nano-scale technologies is presented. To evaluate the usage of stacked devices, the characteristic curves of transistors implemented with a different amount of transistors in stack are obtained and compared to those of a single device. The effects of using stacked devices are further studied with the implementation of a current mirror and the implementation of two different layout topologies, discussing their tradeoffs, advantages and drawbacks. Our methodology facilitates designers to develop a good understanding of the characteristics and limitations of a particular physical design before silicon is back for laboratory testing

Confirmation of symmetrical distributions of clinical attachment loss and tooth loss in a homogeneous Mexican adult male population

Background/purpose To ascertain whether or not clinical attachment loss and tooth loss are present with similar severity and prevalence across the two sides of the mouth in a homogeneous sample of urban male adults. Materials and methods A cross-sectional study was carried out on 161 policemen (a largely homogeneous group in terms of ethnic background, socioeconomic status, sex, occupation, and medical/dental insurance) in Campeche, Mexico. Periodontal examinations were undertaken using the Florida Probe System in a dental chair by one trained and standardized examiner (kappa ≥ 0.60) to determine clinical attachment loss and tooth loss. We examined six sites in all teeth present in the mouth (a maximum of 168 sites, no third molars). Because of correlated data between observations, McNemar (for tooth loss) and Wilcoxon (for attachment loss) signed-rank tests were used to compare right and left sites within the same patient. Results The mean age was 38.4 ± 11.0 years. The mean number of teeth present was 24.4 ± 4.6; the mean number of periodontal sites/person was 146.7 ± 27.8. All P values were ≥ 0.05 (except for attachment loss in the upper first premolars), suggesting that there were no statistically significant differences between the right and left sides for the frequency of presentation of these two conditions. Conclusion Tooth loss and attachment loss measurements largely resemble each other on both sides of the mouth

Analysis of the power balance In the cells of a multilevel cascaded H-Bridge converter

Multilevel cascaded H-Bridge converters (CHB) have been presented as a good solution for high power applications. In this way, several control and modulation techniques have been proposed for this power converter topology. In this paper the steady state power balance in the cells of the single phase two cell CHB is studied. The capability to be supplied with active power from the grid or to deliver active power to the grid in each cell is analyzed according to the dc-link voltages and the desired ac output voltage value. Limits of the maximum and minimum input active power for stable operation of the CHB are addressed. Simulation results are shown to validate the presented analysis

Comparative Study of Contact Repulsion in Control and Mutant Macrophages Using a Novel Interaction Detection

In this paper, a novel method for interaction detection is presented to compare the contact dynamics of macrophages in the Drosophila embryo. The study is carried out by a framework called macrosight, which analyses the movement and interaction of migrating macrophages. The framework incorporates a segmentation and tracking algorithm into analysing the motion characteristics of cells after contact. In this particular study, the interactions between cells is characterised in the case of control embryos and Shot mutants, a candidate protein that is hypothesised to regulate contact dynamics between migrating cells. Statistical significance between control and mutant cells was found when comparing the direction of motion after contact in specific conditions. Such discoveries provide insights for future developments in combining biological experiments with computational analysis

Encapsulación de la piperine presente en la especie Piper tuberculatum utilizando vesículas multilamelares y determinación de su poder antioxidante

The piperine is an alkaloid present in the vegetal species pipilongo (Piper tuberculatum). Antioxidant properties are associated to this plant. It was encapsulated in multilamellar vesicles (MLV). For that, the validation of the extraction methodology through calibration curves of standard piperine by high resolution liquid chromatography (HPLC) was performed, using a column of C18, mobile phase MetOH: H2O (70:30) and detected by UV to 340nm with a fluency rate of 0.7 mL/ min. The lineal and non-lineal ranges were found between 1 and 300 ppm, with R2 of 0.995. During the extraction of the pipilongo fruit, the effect of two factors, solvents and ultrasound power, was studied, for the optimization of conditions and higher extraction of piperine in pipilongo. The maximum concentration of piperine (246.50 ppm) was found, using ethanol as extraction solvent. The piperine was isolated from its extract, using a solution of KOH with 10 % ethanol. It was purified and characterized by melting point, IR, GC-MS y RMN 1H. Once the extract was obtained, it was proceeded to the formation of liposomes. The phosphatidylcholine and cholesterol vesicles were prepared with extract and with piperine at different concentrations and hydrated with buffer pH 7.40. The average size of the particles formed, measured by dynamic light scattering (DLS), was in a range of 299.7–531.9 nm. For the study of antioxidant activity, a solution of DPPH 0.2 mM was prepared and a reaction was carried out with the extract and piperine liposomes and their corresponding free forms. The IC50 calculated for the extract and piperine were 2.8±0.2 and 21333±1499 ppm, respectively. These values of IC50 were compared against a standard of reference Quercetin, prepared under the same conditions. The test with DPPH showed that the released form possesses greater antioxidant activity while in encapsulation form, it attenuates and stabilizes this capacity.La piperina, alcaloide presente en la especie vegetal pipilongo (Piper tuberculatum) a la cual se le asocian propiedades antioxidantes, fue encapsulada en vesículas multilamelares (MLV). Para ello se realizó la validación de la metodología de extracción a través de curvas de calibración de piperina estándar por cromatografía líquida de alta resolución (HPLC) utilizando una columna C18, fase móvil MetOH:H2O (70:30) y detectada por UV a 340 nm con una tasa de flujo de 0.7 mL/min. El rango lineal y linealidad fueron halladas entre 1 a 300 ppm, con R2 de 0.995. En la extracción del fruto de pipilongo se estudió el efecto de dos factores, disolventes y potencia de ultrasonido, para la optimización de condiciones y mayor extracción de piperina en pipilongo. La máxima concentración de piperina (246.50 ppm) fue encontrada en las condiciones de ultrasonido (US 20 KHz a 175W, 40 min) utilizando etanol como disolvente de extracción. Del extracto, se aisló la piperina utilizando una solución de KOH 10% etanólico. Fue purificada y caracterizada mediante punto de fusión, IR, GC-MS y RMN 1H. Una vez obtenido el extracto, se procedió a la formación de liposomas. Las vesículas de fosfatidilcolina y colesterol fueron preparadas con extracto y con piperina a diferentes concentraciones e hidratadas con buffer PBS a pH 7.40. El tamaño promedio de las partículas formadas, medido por dispersión de luz dinámica (DLS), estuvo en un rango de 299.7–531.9 nm. Para el estudio de la actividad antioxidante, se preparó una solución de DPPH 0.2 mM y se llevó a reacción con los liposomas de extracto y de piperina y sus correspondientes formas libres durante 60 min, medidos a 520 nm. El IC50 calculado para el extracto y la piperina fueron 2.8±0.2 y 21333±1499 ppm, respectivamente. Estos valores de IC50 fueron comparados frente a un estándar de referencia preparado bajo las mismas condiciones, quercetina (IC50 2.5±0.1 ppm). El ensayo con DPPH mostró que la forma liberada posee mayor actividad antioxidante mientras que en la encapsulación atenúa y estabiliza esta capacidad

KNOWING THE ELECTORAL PREFERENCE THROUGH POPULARITY ON FACEBOOK (CONOCIENDO LA PREFERENCIA ELECTORAL A TRAVÉS DE LA POPULARIDAD EN FACEBOOK)

AbstractThis study examines the possibility of identifying the political-electoral trend of a presidential election based on the popularity of candidates on Facebook. We collected data from Facebook accounts of the four candidates to Mexico’s Presidential in 2012, and we analyzed the data against the election result of July 1, 2012. We found a positive relationship between the number of friends and votes, corroborating previous research. Moreover, we introduced the number of times the Facebook like button was clicked by friends as a variable to measure the voting trends, finding that it has a stronger correlation with votes.Keywords: elections, political-electoral trend, political participation, popularity, social network sites.ResumenEste estudio examina la posibilidad de identificar la tendencia político-electoral de una elección presidencial a partir de la popularidad de los candidatos en Facebook. Se recolectaron datos de las cuentas en Facebook de los cuatro candidatos a la Presidencial de México en 2012 y se analizaron contra los resultados electorales del primero de Julio del 2012. Se encontró una relación positiva entre el número de amigos y los votos conseguidos en la elección, corroborando investigaciones previas. Además, se introdujo la cantidad de veces que los amigos hicieron clic en el botón me gusta de Facebook como una variable para medir la tendencia electoral, obteniendo una mayor correlación con los votos.Palabras Claves: elecciones, participación política, popularidad, sitio de redes sociales, tendencia político-electoral

Recombination reduction on lead halide perovskite solar cells based on low temperature synthesized hierarchical TiO2 nanorods

Intensive research on the electron transport material (ETM) has been pursued to improve the efficiency of perovskite solar cells (PSCs) and decrease their cost. More importantly, the role of the ETM layer is not yet fully understood, and research on new device architectures is still needed. Here, we report the use of three-dimensional (3D) TiO2 with a hierarchical architecture based on rutile nanorods (NR) as photoanode material for PSCs. The proposed hierarchical nanorod (HNR) films were synthesized by a two-step low temperature (180 °C) hydrothermal method, and consist of TiO2 nanorod trunks with optimal lengths of 540 nm and TiO2 nanobranches with lengths of 45 nm. Different device configurations were fabricated with TiO2 structures (compact layer, NR and HNR) and CH3NH3PbI3, using different synthetic routes, as the active material. PSCs based on HNR-CH3NH3PbI3 achieved the highest power conversion efficiency compared to PSCs with other TiO2 structures. This result can be ascribed mainly to lower charge recombination as determined by impedance spectroscopy. Furthermore, we have observed that the CH3NH3PbI3 perovskite deposited by the two-step route shows higher efficiency, surface coverage and infiltration within the structure of 3D HNR than the one-step CH3NH3PbI3−xClx perovskite.This work was supported by the Universitat Jaume I (project 12I361.01/1), the Spanish MINECO (project MAT2013-47192- C3-1-R), CONACYT-México (project CB-2010/153270) and UNAM (PAPIIT-IN1030