Compact discs as versatile cost-effective substrates for releasable nanopatterned aluminium films

We demonstrate that standard polycarbonate compact disk surfaces can provide unique adhesion to Al films that is both strong enough to permit Al film nanopatterning and weak enough to allow easy nanopatterned Al film detachment using Scotch tape. Transferred Al nanohole arrays on Scotch tape exhibit excellent optical and plasmonic performance

Optical Slot-Waveguide Based Biochemical Sensors

Slot-waveguides allow light to be guided and strongly confined inside a nanometer-scale region of low refractive index. Thus stronger light-analyte interaction can be obtained as compared to that achievable by a conventional waveguide, in which the propagating beam is confined to the high-refractive-index core of the waveguide. In addition, slot-waveguides can be fabricated by employing CMOS compatible materials and technology, enabling miniaturization, integration with electronic, photonic and fluidic components in a chip, and mass production. These advantages have made the use of slot-waveguides for highly sensitive biochemical optical integrated sensors an emerging field. In this paper, recent achievements in slot-waveguide based biochemical sensing will be reviewed. These include slot-waveguide ring resonator based refractometric label-free biosensors, label-based optical sensing, and nano-opto-mechanical sensors

A theoretical comparison of strip and vertical slot-waveguide

For biosensing applications where small refractive index variations of the surrounding medium are monitored, light needs to have a strong interaction with such a surrounding biological medium. This is not the case for classical rib and strip waveguides where light is predominantly guided in the high index material. However, in slot waveguides, light is confined in a low index slot region sandwiched between two high index rails and due to the discontinuity of the electric field at the interface between the rails and slot, a significant fraction of the electromagnetic field is localized in the slot. As such slot waveguides present an interesting alternative for biosensing applications especially when made using silicon nitride which permits slot widths of up to 200nm and as such reachable fabrication tolerances, and reduced propagation losses compared to silicon slot waveguides with its higher refractive index contrast. Furthermore, for biosensing, the wider slot facilitates sample transport and using a multiple-slot structure, further enhancement of the optical confinement in low index slot regions is possible. In this paper we present work in progress of theoretical modeling for strip, slot and multiple-slot waveguides and compare their characteristics for sensing purposes

Molecular recognition with nanostructures fabricated by photopolymerization within metallic subwavelength apertures

The first demonstration of fabrication of submicron lateral resolution molecularly imprinted polymer (MIP) patterns by photoinduced local polymerization within metal subwavelength apertures is reported. The size of the photopolymerized MIP features is finely tuned by the dose of 532 nm radiation. Rhodamine 123 (R123) has been selected as a fluorescent model template to prove the recognition capability of the MIP nanostructures, which has been evaluated by fluorescence lifetime imaging microscopy (FLIM) with single photon timing measurements. The binding selectivity provided by the imprinting effect has been confirmed in the presence of compounds structurally related to R123. These results pave the way to the development of nanomaterial architectures with biomimetic artificial recognition properties for environmental, clinical and food testing

Potencial Analítico de los Polímeros de Impronta Molecular (MIPs) como Elementos de Reconocimiento Biomimético

Los polímeros de impronta molecular (MIPs) son materiales sintéticos que presentan propiedades de reconocimiento molecular específico hacia determinados compuestos. Estos materiales con “memoria selectiva” presentan un elevado potencial analítico como sustitutos de elementos de reconocimiento de origen biológico para el desarrollo de sensores, como sorbentes en procesos de extracción en fase sólida (SPE) y como fases estacionarias para HPLC y CE. La síntesis de estos materiales se basa en la formación de una estructura polimérica, altamente entrecruzada, alrededor de una molécula que actúa como plantilla que se extrae después de la polimerización. De esta forma, el MIP contendrá sitios de unión que son complementarios a la molécula plantilla en forma, tamaño y distribución de grupos funcionales que permiten su reconocimiento posterior, de forma selectiva Los MIPs suelen presentar ventajas interesantes en comparación con los receptore

Definición de los costos ocultos del ausentismo laboral en “San Isidro Distribuciones S.A.S” y aplicación de la metodología de Heinrich

A lo largo de la historia en las organizaciones de nuestro país el ausentismo laboral se ha definido, analizado y descrito a través de diversos factores determinados en función de indicadores. Sin embargo, la estimación de costos ocultos como, cuanto le cuesta a la organización reemplazar el trabajador ausente, o el valor económico que representa asumir esas horas /días de ausentismo, el estimar que valía tienen los conocimientos del trabajador que se encuentra ausente, el coste del tiempo de los profesionales de seguridad y salud en el trabajo que hicieron sus actividades pero que no fueron efectivas en la totalidad de los trabajadores, el costo beneficio del trabajador ausente versus el nuevo trabajador; ha sido un reto organizacional para el departamento de gestión humana. Es por esto que las empresas al realizar el análisis del costo del ausentismo, regularmente se define un valor estimado que engloba los costos ocultos. Sin embargo, sería de gran valor para las organizaciones definir una herramienta que permite valorizar los costos ocultos del ausentismo laboral, pero al mismo tiempo dejar literatura sobre cuáles son esos costos ocultos que se identificaron con el desarrollo de este trabajo, adicionalmente se realizó la validación de la Metodología de Heinrich, mediante la aplicación de la fórmula propuesta, facilitando de alguna manera poder replicar los resultados de esta investigación en otras organizaciones, diferentes a distribuciones San Isidro y así robustecer el inventario de costos ocultos el cual será alimentado con nuevos descubrimientos en futuros estudios.Throughout history in organizations of our country, absenteeism has been defined, analyzed and described through various factors determined based on indicators; however, the estimate of hidden costs, such as how much it costs to the organization to replace the absent worker, or the economic value of assuming those hours/days of absenteeism, estimating the value of the knowledge of the absent worker, the time cost of occupational health and safety professionals who carried out their activities, but were not effective in all workers, the cost - benefit of the absent worker versus a new worker; It has been an organizational challenge for the human management department. This is why companies, when analyzing the cost of absenteeism, regularly define an estimated value that includes hidden costs; however, it would be of great value for organizations to define a tool that allows valuing the hidden costs of work absenteeism, but at the same time leaving some literature on what are those hidden costs that were identified with the development of this research, additionally the validation was carried out of the Heinrich Methodology, through the application of the proposed formula, facilitating in some way to replicate the results of this research in other organizations, different from San Isidro distributions and thus, strengthening the inventory of hidden costs which will be fed with new discoveries in future studies

Biosensado con redes de nanoagujeros en oxido de aluminio

Se presenta la explotación analítica de redes de nanoagujeros de óxido de aluminio fabricados sobre sustratos de policarbonato.1 Este novedoso dispositivo se basa en la resonancia de plasmón superficial para monitorizar procesos de bioreconocimiento sin marcaje. El bajo coste de los materiales empleados (policarbonato y aluminio) y la compatibilidad de este dispositivo con las tecnologías de disco compacto encierra un gran potencial para el desarrollo de biosensores

Integrated slot-waveguide microresonator for biochemical sensing

A novel integrated biochemical sensor based on a slot-waveguide [1] microring resonator is demonstrated. The microresonator is fabricated on a Si3N4/SiO2 material platform [2] by using conventional microfabrication techniques, such as Si thermal oxidation, chemical vapour deposition, electron-beam lithography and reactive ion etching. The sensor consists of a 70-μm-radius ring resonator formed by a slot-waveguide [1] having a slot-width of 200 nm. The operation wavelength is 1.3 μm. The device is exposed to different water-ethanol solutions and its transmission spectrum is measured. A linear shift of the resonant wavelength with increasing ambient refractive index of 212 nm/refractive index units (RIU) is observed. This value is more than twice larger than those of strip-waveguide ring resonator biochemical sensors, indicating that higher analyte-probe light interaction occurs in our slot-waveguide sensor as compared to those based on conventional strip waveguides. The sensor detects a minimal refractive index variation of 2x10-4 RIU, limited by the wavelength resolution of the light source (50 pm). Simulations indicate that the slot region is partially filled when the sensor is exposed to an aqueous solution. We also demonstrate the capability of our sensor to measure higher index fluids such as isopropanol (n=1.37) and cyclohexane (n=1.42)