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In this work, we present a compact LIBS sensor developed for characterization of samples on a crime scene following requirements of law enforcement agencies involved in the project. The sensor operates both in a tabletop mode, for aside measurements of swabbed materials or taken fragments, and in handheld mode where the sensor head is pointed directly on targets at the scene. The sensor head is connected via an umbilical to an instrument box that could be battery-powered and contains also a color camera for sample visualization, illumination LEDs, and pointing system for placing the target in focus. Here we describe the sensor's architecture and functionalities, the optimization of the acquisition parameters, and the results of some LIBS measurements. On nano-plotted traces at silica wafer and in optimized conditions, for most of the elements the detection limits, in term of the absolute element masses, were found to be below 10 picograms. We also show results obtained on some representative materials, like fingerprints, swabbed soil and gunshot residue, varnishes on metal, and coated plastics. The last, solid samples were used to evaluate the depth profiling capabilities of the instrument, where the recognition of all four car paint layers was achieved.
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Stand-off detection of latent traces avoids the scene alteration that might occur during close inspection by handheld forensic lights. Here, we describe a novel sensor, named Crime Light Imaging (CLI), designed to perform high-resolution photography of targets at a distance of 2-10 m and to visualize some common latent traces. CLI is based on four high-power illumination LEDs and one color CMOS camera with a motorized objective plus frontal filters; the LEDs and camera could be synchronized to obtain short-exposure images weakly dependent on the ambient light. The sensor is integrated into a motorized platform, providing the target scanning and necessary information for 3D scene reconstruction. The whole system is portable and equipped with a user-friendly interface. The preliminary tests of CLI on fingerprints at distance of 7 m showed an excellent image resolution and drastic contrast enhancement under green LED light. At the same distance, a small (1 µL) blood droplet on black tissue was captured by CLI under NIR LED, while a trace from 15 µL semen on white cotton became visible under UV LED illumination. These results represent the first demonstration of true stand-off photography of latent traces, thus opening the way for a completely new approach in crime scene forensic examination.
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The spatial distribution of PM1 components in the Barcelona metropolitan area was investigated using on-road mobile measurements of atmospheric particle- and gas-phase compounds during the DAURE campaign in March 2009. Positive matrix factorization (PMF) applied to organic aerosol (OA) data yielded 5 factors: hydrocarbon-like OA (HOA), cooking OA (COA), biomass burning OA (BBOA), and low volatility and semivolatile oxygenated OA (LV-OOA and SV-OOA). The area under investigation (â¼500 km(2)) was divided into six zones (city center, harbor, industrial area, precoastal depression, 2 mountain ranges) for measurements and data analysis. Mean zonal OA concentrations are 4.9-9.5 µg m(-3). The area is heavily impacted by local primary emissions (HOA 14-38%, COA 10-18%, BBOA 10-12% of OA); concentrations of traffic-related components, especially black carbon, are biased high due to the on-road nature of the measurements. The formation of secondary OA adds more than half of the OA burden outside the city center (SV-OOA 14-40%, LV-OOA 17-42% of OA). A case study of one measurement drive from the shore to the precoastal mountain range furthest downwind of the city center indicates the importance of nonfossil over anthropogenic secondary OA based on OA/CO.
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Aerosoles/análisis , Contaminantes Atmosféricos/análisis , Modelos Teóricos , Compuestos Orgánicos/análisis , Biomasa , Ciudades , Culinaria , Geografía , Material Particulado/análisis , España , VolatilizaciónRESUMEN
A new Raman-based apparatus for proximal detection of energetic materials on people, was developed and tested for the first time. All the optical and optoelectronics components of the apparatus, as well as their optical matching, were carefully chosen and designed to respect international eye-safety regulations. In this way, the apparatus is suitable for civil applications on people in public areas such as airports and metro or railway stations. The acquisition software performs the data analysis in real-time to provide a fast response to the operator. Moreover, it allows for deployment of the apparatus either as a stand alone device or as part of a more sophisticated warning system architecture made up of several sensors. Using polyamide as substrate, the apparatus was able to detect surface densities of ammonium nitrate (AN), 2-methyl-1,3,5-trinitrobenzene (TNT), 3-nitrooxy-2,2-bis(nitrooxymethyl)propyl] nitrate (PETN) and urea nitrate (UN) in the range of 100-1000 µg/cm² at a distance of 6.4 m using each time a single laser pulse of 3 mJ/cm². The limit of detection calculated for AN is 289 µg/cm². AN and UN provided the highest percentages of true positives (>82% for surface densities of 100-400 µg/cm² and fingerprints) followed by TNT and PETN (17%-70% for surface densities of 400-1000 µg/cm² and fingerprints).
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Monitoreo del Ambiente/métodos , Sustancias Explosivas/análisis , Rayos Láser , Espectrometría Raman/métodos , Defensa Civil , Monitoreo del Ambiente/instrumentación , Humanos , Terrorismo/prevención & controlRESUMEN
We report the results of proximal Raman investigations at a distance of 7 m, to detect traces of explosives (from 0.1 to 0.8 mg/cm(2)) on common clothes with a new eye-safe apparatus. The instrument excites the target with a single laser shot of few ns (10(-9)s) in the UV range (laser wavelength 266 nm) detecting energetic materials like Pentaerythritol tetranitrate (PETN), Trinitrotoluene (TNT), Urea Nitrate (UN) and Ammonium Nitrate (AN). Samples were prepared using a piezoelectric-controlled plotter device to realize well-calibrated amounts of explosives on several cm(2). Common fabrics and tissues such as polyester, polyamide and leather were used as substrates, representative of base-materials used in the production of jackets or coats. Other samples were prepared by touching the substrate with a silicon finger contaminated with explosives, to simulate a spot left by contaminated hands on a jacket or bag during the preparation of an improvised explosive device (IED) by a terrorist. The observed Raman signals showed some peculiar molecular bands of the analyzed compounds, allowing us to identify and discriminate them with high sensitivity and selectivity, also in presence of the interfering signal from the underlying fabric. A dedicated algorithm was developed to remove noise and fluorescence background from the single laser shot spectra and an automatic spectral recognition procedure was also implemented, evaluating the intensity of the characteristic Raman bands of each explosive and allowing their automatic classification. Principal component analysis (PCA) was used to show the discrimination potentialities of the apparatus on different sets of explosives and to highlight possible criticalities in the detection. Receiver operating characteristic (ROC) curves were used to discuss and quantify the sensitivity and the selectivity of the proposed recognition procedure. To our knowledge the developed device is at the highest sensitivity nowadays achievable in the field of eye-safe, Raman devices for proximal detection.
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Sustancias Explosivas/análisis , Ojo , Análisis de Componente Principal , Curva ROC , Seguridad , Espectrometría Raman/instrumentación , Rayos Ultravioleta , Límite de DetecciónRESUMEN
Introducción: el estudio de la historia de la salud pública forma parte de las memorias de la medicina, y abarca cuándo, cómo y el porqué el hombre se agrupó en instituciones y organizaciones que le permitieran hacer frente a las enfermedades en su propio medio social. Los locales usados para el desarrollo de los servicios médicos, su ubicación y nivel de confort, juegan en papel preponderante en la calidad de dichos servicios. Objetivo: describir la evolución histórica del local que ocupa el actual Policlínico Universitario "Luis Augusto Turcios Lima" de la ciudad de Pinar del Río y el por qué de su nombre. Material y método: esta investigación cualitativa tributa conocimientos sobre el desarrollo histórico y local del inmueble de referencia y que hoy cumple el rol de sede de una institución de salud. Como método general se tuvo en cuenta el dialéctico-materialista y se usaron métodos empíricos como la entrevista. Los métodos teóricos usados fueron: histórico-lógico y análisis-síntesis así como el análisis de documentos históricos. Resultados: la confección de una reseña histórica del local y su nombre. Conclusiones: precisar la historia de este inmueble y la del hombre que lleva su nombre constituye una fuente de conocimientos históricos para sus trabajadores, estudiantes y la comunidad.
Introduction: the study of the history of public health is part of the memories of medicine, and covers how and why the mankind was grouped into institutions and organizations to be allowed to address the disease in their own social environment. Local used for the development of medical services, location and comfort level, play in important role in the quality of those services. Objective: to describe the historical evolution of the current premises of "Luis Augusto Turcios Lima" University Clinic from the city of Pinar del Rio and the reason for its name. Methods: This qualitative research is taxed knowledge about the historical development and Local Property reference and now plays the role of host to a health facility. As a general method took into account the dialectical-materialist, empirical methods were used as the interview. The theoretical methods used were: logical and historical analysis-synthesis and analysis of historical documents. Results: the making of a historical overview of the local and name. Conclusions: we have clarified the history of this building and the man that bears his name is a source of historical knowledge for its employees, students and the community.