Search results for "PreP"
showing 10 items of 1334 documents
Determination of the mineral composition of foods by infrared spectroscopy: a review of a green alternative.
2014
The determination of mineral composition of foods involves, in most cases, the use of long and tedious sample preparation, which consumes acids and reagents and sometimes requires the use of expensive instrumentation. This is the main reason for the search for direct analytical procedures, based on the use of infrared sample spectra and chemometrics, to model the signals in order to determine the presence of essential and trace toxic elements in foods. The state-of-the-art of the research in this field has been established in the present review article from the critical evaluation of articles available in the literature. Chemometric methods employed and their validation, together with a dis…
A Novel Iris Recognition System based on Micro-Features
2007
In this paper a novel approach for iris recognition system based on iris micro-features is proposed. The proposed system follows the minutiae based approach developed for fingerprint recognition systems. The proposed system uses four iris microfeatures, considered as minutiae, for identification. The individualized characteristics are nucleus, collarette, valleys and radius. Iris recognition is divided in three main phases: image preprocessing, micro-features extraction and matching. The algorithm has been tested on CASIA v1.0 iris image database obtaining an high accuracy. The obtained experimental results have been analyzed and compared with the Daugman based approach.
Image enhancement in simple fingerprint minutiae extraction algorithm using crossing number on valley structure
2007
In fingerprint recognition system, fingerprint feature extraction algorithm requires good quality fingerprint images to produce good results. Therefore, one step in the preprocessing stage is image enhancement to improve the quality of poor fingerprint image, so the minutiae points can be detected with good results. In this paper, we present how this enhancement process in simple minutiae detection algorithm using crossing number on valley structure improves detection of true minutiae.
A statistical calibration model for Affymetrix probe level data
2009
Gene expression microarrays allow a researcher to measure the simultaneous response of thousands of genes to external conditions. Affymetrix GeneChip{ $Ⓡ$} expression array technology has become a standard tool in medical research. Anyway, a preprocessing step is usually necessary in order to obtain a gene expression measure. Aim of this paper is to propose a calibration method to estimate the nominal concentration based on a nonlinear mixed model. This method is an enhancement of a method proposed in Mineo et al. (2006). The relationship between raw intensities and concentration is obtained by using the Langmuir isotherm theory.
An anti-zipping preparation system (method and instrument) for curved root canals: A preliminary report
1996
A new instrument and method of preparation of curved canals, with which preparation effects such as "zips" and "elbowing" at the apical third can be easily eliminated, is described. The new system was designed to incorporate requirements previously established during clinical and laboratory experiments.
Influence of Operator's Experience on Root Canal Shaping Ability with a Rotary Nickel-Titanium Single-File Reciprocating Motion System
2013
The aim of this study was to evaluate the influence of the operator's experience on the shaping of double-curvature simulated root canals with a nickel-titanium single-file reciprocating motion system.Sixty double-curvature root canals simulated in methacrylate blocks were prepared by 10 students without any experience in endodontics and by 10 professionals who had studied endodontics at the postgraduate level. The Reciproc-VDW system's R25 file was used in the root canal preparation. The blocks were photographed before and after the instrumentation, and the time of instrumentation was also evaluated. Changes in root canal dimensions were analyzed in 6 positions.Significant differences (P.0…
Controlled release using mesoporous materials containing gate-like scaffoldings.
2009
The use of gated mesoporous silica solids as suitable systems for controlled-release protocols is reviewed. These materials are based on mesoporous silica supports that can be prepared with tailor-made pores of around 2 - 10 nm and that show a very large specific surface area (up to 1200 m(2)/g), thus having a large load capacity. The solids can be additionally functionalised in the external surface with gate-like systems that can be opened on command to allow cargo release. Light, redox reactions, pH, temperature, polarity and enzyme-driven protocols are shown. The possible application in drug delivery protocols is discussed.
Molecular topology as novel strategy for discovery of drugs with aβ lowering and anti-aggregation dual activities for Alzheimer's disease.
2014
Background and Purpose: In this study, we demonstrate the use of Molecular topology (MT) in an Alzheimer's disease (AD) drug discovery program. MT uses and expands upon the principles governing the molecular connectivity theory of numerically characterizing molecular structures, in the present case, active anti-AD drugs/agents, using topological descriptors to build models. Topological characterization has been shown to embody sufficient molecular information to provide strong correlation to therapeutic efficacy. Experimental Approach: We used MT to include multiple bioactive properties that allows for the identification of multifunctional single agent compounds, in this case, the dual func…
Finely Tuned Temperature-Controlled Cargo Release Using Paraffin-Capped Mesoporous Silica Nanoparticles
2011
[EN] Trapped: Mesoporous silica nanoparticles were loaded with a fluorescent guest and functionalized with octadecyltrimethoxysilane. The alkyl chains interact with paraffins, which build a hydrophobic layer around the particle (see picture). Upon melting of the paraffin, the guest molecule is released, as demonstrated in cells for the guest doxorubicin. The release temperature can be tuned by choosing an appropriate paraffin. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Polymorphism control of an active pharmaceutical ingredient beneath calixarene-based Langmuir monolayers.
2014
This communication demonstrates the possibility to nucleate and grow different crystalline polymorphic forms of gabapentin (GBP) using, as nucleation templates, Langmuir monolayers of an amphiphilic calixarene at different packing densities.