Ac

Este libro brinda una introducción a la electrónica en semiconductores -también llamada de estado
sólido- para carreras de ingeniería en electrónica, electricidad, computadoras, comunicaciones, control y sistemas. Provee una explicación de los mecanismos de conducción eléctrica en Silicio,
que luego se utiliza para el desarrollo de cuatro dispositivos fundamentales de la electrónica actual: el diodo de juntura, el capacitor Metal-Oxido-Semiconductor (MOS), el transistor MOS, y el transistor bipolar de juntura. El libro conduce al estudiante a que entienda el funcionamiento de cada dispositivo, partiendo de sus principios fundamentales, y que a partir de allí, comprenda en profundidad los diferentes modelos eléctricos que puede utilizar para representarlo, sus alcances y limitaciones. El objetivo último es que el estudiante conozca y sepa utilizar los distintos modelos de los dispositivos electrónicos, de acuerdo al rango de amplitud y frecuencia, para su utilización futura en el diseño y análisis de circuitos.

Polymer hydrogels have been widely explored as therapeutic delivery matrices because of their ability to present sustained, localized and controlled release of bioactive factors. Bioactive factor delivery from injectable biopolymer hydrogels provides a versatile approach to treat a wide variety of diseases, to direct cell function and to enhance tissue regeneration. The innovative development and modification of both natural-(e.g., alginate (ALG), chitosan, hyaluronic acid (HA), gelatin, heparin (HEP), etc.) and synthetic-(e.g., polyesters, polyethyleneimine (PEI), etc.) based polymers has resulted in a variety of approaches to design drug delivery hydrogel systems from which loaded therapeutics are released. This review presents the state-of-the-art in a wide range of hydrogels that are formed though self-assembly of polymers and peptides, chemical crosslinking, ionic crosslinking and biomolecule recognition. Hydrogel design for bioactive factor delivery is the focus of the first s...

The "days of omnipotence". Luigi Gedda at the electoral appointment of 1952

This article draws on the documents, almost entirely unedited, from the personal archive of Luigi Gedda, the founder of the Civic Committees (CC) and champion of the catholic Activism during the WW2 postwar. In this paper is examined in particular the Gedda's thought and role in preparation for the administrative elections of 1951-1952, which formed a fundamental preview of the political consultations of 1953. The declines in support for the DC, accompanied with the rise of socialist-communist forces constituted a source of great concern for the Holy See, which devised the famous "Operation Sturzo", trying to force De Gasperi to make an alliance with the right parties, like the Monarchist National Party (PNM) and the neo-fascist Italian Social Movement (MSI), to which, however, the Christian Democracy Party (DC) had a strong reserve because of their unconstitutional nature. The new documents presented in this paper help to better delineate the "political project" of Luigi Gedda, his personal evaluation of DC and of the role of catholics in italian policy, the network of contacts between the CC and the Italian Social Movement and the opposition encountered within the national leadership of Catholic Action (AC).

keywords: Luigi Gedda - Civic Committees, Catholic Action - Holy See and italian elections.

The Piedmont Zone of the Indo-Gangetic Plain contains numerous, laterally coalescing small alluvial fans. The Latest Pleistocene–Holocene 30 km long Gaula Fan can be divided into gravelly proximal fan (0–14 km down-stream), gravel-sand rich mid fan (14–22 km) and sand–mud dominated distal fan (22–30 km). The fan succession is composed of two fan expansion cycles A and B. Separated by an undulatory erosional contact of regional extent, cycle A is characterized by river borne clast-supported gravelly deposits, and the overlying fan expansion cycle B by matrix-supported gravely debris flows. The main process behind fan development has been lateral migration of channels over the fan surface probably due to rapid sedimentation caused by increased sediment supply, and the fluctuating water budget in response to changing climate. The water laid expansion cycle A represents a humid phase. The debris flow deposits of expansion cycle B suggest a dry phase. Approximately between 8 and 3 Ka, cycle B also indicates a phase of tectonic instability in the Siwalik Hills forming the mountain front. The tectonic activity caused incision of rivers into the fan surface, and in turn resulted in reduced fan-building activity. At present the fan surface is accreting by sheet flow processes.

Redox-active self-assembled monolayers (SAMs) provide an excellent platform for investigating electron transfer kinetics. Using a well-defined bridge, a redox center can be positioned at a fixed distance from the electrode and electron transfer kinetics probed using a variety of electrochemical techniques. Cyclic voltammetry, AC voltammetry, electrochemical impedance spectroscopy, and chronoamperometry are most commonly used to determine the rate of electron transfer of redox-activated SAMs. A variety of redox species have been attached to SAMs, and include transition metal complexes (e.g., ferrocene, ruthenium pentaammine, osmium bisbipyridine, metal clusters) and organic molecules (e.g., galvinol, C(60)). SAMs offer an ideal environment to study the outer-sphere interactions of redox species. The composition and integrity of the monolayer and the electrode material influence the electron transfer kinetics and can be investigated using electrochemical methods. Theoretical models ha...

OBJECTIVES:

A cross-sectional study was conducted to determine the level of agreement between the Dental Aesthetic Index (DAI) and the Aesthetic Component (AC) of the Index of Orthodontic Treatment Need (IOTN).
METHODS:

DAI and AC scores were recorded in 728 subjects (340 females and 388 males, aged 11-20 years). The percentage of subjects needing treatment and the different treatment categories for the DAI and AC were gender compared. Spearman's rank correlation coefficient (rho) was used to explore the relationship between the DAI and AC scores. Observer determined and Kappa statistics were used to analyse the diagnostic level of agreement between the DAI and AC, sorted into 'yes' or 'no' categories of orthodontic treatment need.
RESULTS:

According to the DAI and AC, 21.8 and 10.9% of subjects were in need of treatment, respectively. Significant positive correlations existed between the DAI and AC scores (rho = 0.795). The DAI had a lower treatment need threshold compared with the AC. The Kappa statistics and percentage agreement between the DAI and AC was 0.55 (95% CI: 0.46-0.63) and 87.6%, respectively.
CONCLUSION:

The DAI and AC showed strong association. However, only a moderate level of diagnostic agreement was identified (12.4% difference in observed percentage agreement) which highlights the need for a unified and universal orthodontic index for consideration when interpreting, comparing, or quantifying treatment needs.