High refractive index Fresnel lens on a fiber fabricated by nanoimprint lithography for immersion applications.

In this Letter, we present a Fresnel lens fabricated on the end of an optical fiber. The lens is fabricated using nanoimprint lithography of a functional high refractive index material, which is suitable for mass production. The main advantage of the presented Fresnel lens compared to a conventional fiber lens is its high refractive index (n=1.68), which enables efficient light focusing even inside other media, such as water or an adhesive. Measurement of the lens performance in an immersion liquid (n=1.51) shows a near diffraction limited focal spot of 810 nm in diameter at the 1/e2 intensity level for a wavelength of 660 nm. Applications of such fiber lenses include integrated optics, optical trapping, and fiber probes.

Printable photonic crystals with high refractive index for applications in visible light.

Nanoimprint lithography (NIL) of functional high-refractive index materials has proved to be a powerful candidate for the inexpensive manufacturing of high-resolution photonic devices. In this paper, we demonstrate the fabrication of printable photonic crystals (PhCs) with high refractive index working in the visible wavelengths. The PhCs are replicated on a titanium dioxide-based high-refractive index hybrid material by reverse NIL with almost zero shrinkage and high-fidelity reproducibility between mold and printed devices. The optical responses of the imprinted PhCs compare very well with those fabricated by conventional nanofabrication methods. This study opens the road for a low-cost manufacturing of PhCs and other nanophotonic devices for applications in visible light.

Printable planar lightwave circuits with a high refractive index.

We report a novel nanofabrication method to fabricate printable integrated circuits with a high refractive index working in the visible wavelength range. The printable planar ligthwave circuits are directly imprinted by ultra-violet nanoimprinting into functional TiO2-based resist on the top of planar waveguide core films. The printed photonic circuits are composed of several elementary components including ridge waveguides, light splitters and digital planar holograms. Multi-mode ridge waveguides with propagation losses around 40 dB cm(-1) at 660 nm wavelength, and, on-chip demultiplexers operated in the visible range with 100 channels and a spectral channel spacing around 0.35 nm are successfully demonstrated.

A route for fabricating printable photonic devices with sub-10 nm resolution.

A novel and robust route for high-throughput, high-performance nanophotonics-based direct imprint of high refractive index and low visible wavelength absorption materials is presented. Sub-10 nm TiO2 nanostructures are fabricated by low-pressure UV-imprinting of an organic-inorganic resist material. Post-imprint thermal annealing allows optical property tuning over a wide range of values. For instance, a refractive index higher than 2.0 and an extinction coefficient close to zero can be achieved in the visible wavelength range. Furthermore, the imprint resist material permits fabrication of crack-free nanopatterned films over large areas and is compatible for fabricating printable photonic structures.

Facile route of flexible wire grid polarizer fabrication by angled-evaporations of aluminum on two sidewalls of an imprinted nanograting.

In this study, we report a new method to fabricate a wire grid polarizer (WGP) that greatly relaxes the requirement on patterning and etching, and can be easily applied to produce flexible WGPs. The technique is to pattern a high aspect ratio and narrow linewidth grating by nanoimprint lithography followed by two angled aluminum depositions in opposite directions to produce the narrow spacing between the aluminum lines required for a visible band WGP. Anisotropic reactive ion etching is used to remove the aluminum deposited at the top of the grating but leave the aluminum layer on the grating sidewalls, thereby forming a metal wire grid with much smaller spacings than a lithographically defined grating. As a result, the fabricated WGP showed good performance in a wide range of visible wavelength.

Nanoimprinted High-Refractive Index Active Photonic Nanostructures Based on Quantum Dots for Visible Light.

A novel method to realizing printed active photonic devices was developed using nanoimprint lithography (NIL), combining a printable high-refractive index material and colloidal CdSe/CdS quantum dots (QDs) for applications in the visible region. Active media QDs were applied in two different ways: embedded inside a printable high-refractive index matrix to form an active printable hybrid nanocomposite, and used as a uniform coating on top of printed photonic devices. As a proof-of-demonstration for printed active photonic devices, two-dimensional (2-D) photonic crystals as well as 1D and 2D photonic nanocavities were successfully fabricated following a simple reverse-nanoimprint process. We observed enhanced photoluminescence from the 2D photonic crystal and the 1D nanocavities. Outstandingly, the process presented in this study is fully compatible with large-scale manufacturing where the patterning areas are only limited by the size of the corresponding mold. This work shows that the integration of active media and functional materials is a promising approach to the realization of integrated photonics for visible light using high throughput technologies. We believe that this work represents a powerful and cost-effective route for the development of numerous nanophotonic structures and devices that will lead to the emergence of new applications.

Sensibilidad antimicrobiana y mortalidad intrahospitalaria de infecciones comunitarias y nosocomiales en la Unidad de Cuidados Intensivos del Hospital Ángeles del Carmen / Antimicrobial susceptibility and mortality of community and nosocomial acquired infections in the Intensive Care Unit at Hospital Ángeles del Carmen / Susceptibilidade antimicrobiana e mortalidade hospital por infecções comunitárias e nosocomiais na Unidade de Terapia Intensiva do Hospital Ángeles del Carmen

Resumen: Introducción: el manejo de antibióticos en las unidades de cuidados intensivos (UCI) es un tema prioritario. Conocer la epidemiología bacteriana y su sensibilidad es fundamental para aumentar la sobrevida de nuestros pacientes. Material y métodos: se realizó un estudio tipo cohorte retrospectiva en la Unidad de Cuidados Intensivos del Hospital Ángeles del Carmen durante el periodo de 2018 a 2020 en pacientes con infección documentada y con cultivo positivo. Se obtuvo el patrón de sensibilidad antimicrobiana y se analizó de acuerdo al origen Gram, tipo de infección, reactantes de fase aguda y mortalidad. Se realizó comparación de medias y proporciones con χ2, t de Student y ANOVA. Se obtuvieron razones de desventajas (OR) para identificar variables asociadas a resolución. Se consideró un valor de p < 0.05 para significancia estadística. Resultados: se analizaron 308 cultivos bacterianos obtenidos de 188 pacientes, principalmente de origen respiratorio, urinario y torrente sanguíneo (76.7%), de origen nosocomial (65.3%), con predominio de gram-negativos (65%) multidrogorresistentes. La procedencia comunitaria se asoció más a infección que la nosocomial (85 versus 61.7%, OR 3.5, IC 95% 1.93-6.45, p < 0.001). El porcentaje de infección fue mayor en gram-negativos (71.8 versus 66%, OR 1.10, IC 95% de 0.91-1.32, p = 0.297). Las infecciones por gram-positivos tuvieron menor porcentaje de mortalidad que aquéllas por gram-negativos (17.9 versus 30.7%, OR 0.49, IC 95% de 0.27-0.88, p = 0.016) así como las infecciones comunitarias en comparación con nosocomiales (17.8 versus 30.8%, OR 0.48, IC 95% de 0.27-0.86, p = 0.013). Conclusión: las bacterias predominantes en nuestra unidad de cuidados críticos son bacilos gram-negativos multidrogorresistentes, provenientes de infecciones respiratorias, urinarias y de torrente sanguíneo. Las infecciones por gram-positivos y adquiridas en la comunidad se asociaron a menor riesgo de mortalidad.

Abstract: Introduction: local identification of antimicrobial susceptibility and resistance patterns must be a priority in intensive care units. Material and methods: a cohort study was conducted in the intensive care unit from 2018 to 2020, identifying patients with an infectious diagnosis and a positive culture, with prospective clinical and laboratory follow-up. Antimicrobial resistance patterns were analyzed according to source, gram, type of infection, acute phase reactants and outcome, comparing means and proportions with χ2, Student t and ANOVA. OR were obtained to identify resolution-associated variables. A p < 0.05 value was considered as statistically significant. Results: 308 cultures were analyzed, obtained from 188 patients. Primary souces were respiratory, urinary and bloodstream (76.7%), 65.3% were from in-hospital infections, and 65% were caused by gram-negative multi-drug resistant bacteria. Community cultures were more associated with infection compares with in-hospital cultures (85 vs 61.7%, OR 3.5, 95% CI 1.93-6.45, p < 0.001). Gram-negative bacteria had a greater association with infection compared with gram-positive (71.8 vs 66%, OR 1.10, 95% CI 0.91-1.32, p = 0.297), but infections caused by gram-positive bacteria had a greater association with resolution (82.1 vs 68.8%, OR 2.07, 95% CI 1.16-3.70, p = 0.019), as well as community infections (82.2 vs 68.7%, OR 2.11, 95% CI 1.18-3.77, p = 0.016). Conclusion: multi-drug resistant gram-negative bacteria were the principal isolates found in respiratory, urine and bloodstream infections in our intensive care unit. Community infections and gram-positive isolates were associated with greater resolution rates.

Resumo: Introdução: a gestão de antibióticos em Unidades de Cuidados Intensivos é uma questão prioritária. Conhecer a epidemiologia bacteriana e sua suscetibilidade é essencial para aumentar a sobrevida de nossos pacientes. Material e métodos: foi realizado um estudo de coorte retrospectivo na Unidade de Terapia Intensiva do Hospital Ángeles del Carmen durante o período de 2018 a 2020, em pacientes com infecção documentada e com cultura positiva. O padrão de sensibilidade antimicrobiana foi obtido e analisado segundo origem, grama, tipo de infecção, reagentes de fase aguda e mortalidade. A comparação de médias e proporções foi feita com χ2, teste t de Student e ANOVA. Razões de desvantagem (OR) foram obtidas para identificar variáveis ​​associadas à resolução. Um valor de p < 0.05 foi considerado para significância estatística. Resultados: foram analisadas 308 culturas bacterianas obtidas de 188 pacientes, principalmente de origem respiratória, urinária e sanguínea (76.7%), de origem nosocomial (65.3%), com predominância de gram-negativos (65%) multirresistentes. A origem comunitária foi mais associada à infecção do que a nosocomial (85 vs 61.7%, OR 3.5, IC 95% 1.93-6.45, p < 0.001). A porcentagem de infecção foi maior para gram-negativos (71.8 vs 66%, OR 1.10, IC 95% 0.91-1.32, p = 0.297). As infecções Gram-positivas tiveram uma taxa de mortalidade menor do que as infecções Gram-negativas (17.9 vs 30.7%, OR 0.49, IC 95% de 0.27-0.88, p = 0.016), bem como infecções comunitárias em comparação com as nosocomiais (17.8 vs 30.8%, OR 0.48, IC 95% de 0.27-0.86, p = 0.013). Conclusão: as bactérias predominantes em nossa unidade de terapia intensiva são bacilos gram-negativos multirresistentes, originários de infecções respiratórias, urinárias e de corrente sanguínea. As infecções gram-positivas e adquiridas na comunidade foram associadas a um menor risco de mortalidade.

Ultrasmall structure fabrication via a facile size modification of nanoimprinted functional silsesquioxane features.

We propose a simple and robust scheme for a precise and controlled fabrication of ultrasmall structures through the direct size modification (either reduction or increment) of functional nanoimprinted silsesquioxane (SSQ) patterns. The size modification of nanopatterned SSQ polymer features was achieved according to two different independent approaches. In the first approach, feature size was reduced by a simple heat-induced mass loss mechanism; in the second approach structure size increment was achieved by building multiple polymeric layers on top of imprinted patterns. The fabricated arrays follow the shape contour of the patterned structures so the original imprinted profile is preserved. The engineered capabilities were applied to produce high resolution stamps for nanoimprinting. These approaches free the need for sophisticated nanofabrication techniques and expensive facilities required for nanopatterning.

High-resolution functional epoxysilsesquioxane-based patterning layers for large-area nanoimprinting.

Epoxysilsesquioxane (SSQ)-based materials have been developed as patterning layers for large-area and high-resolution nanoimprinting. The SSQ polymers, poly(methyl-co-3-glycidoxypropyl) silsesquioxanes (T(Me)T(Ep)), poly(phenyl-co-3-glycidoxypropyl) silsesquioxanes (T(Ph)T(Ep)), and poly(phenyl-co-3-glycidoxypropyl-co-perfluorooctyl) silsesquioxanes (T(Ph)T(Ep)T(Fluo)), were precisely designed and synthesized by incorporating the necessary functional groups onto the SSQ backbone. The materials possess a variety of characteristics desirable for NIL, such as great coatability, high modulus, good mold release, and excellent dry etch resistance. In particular, the presence of epoxy functional groups allows the resists to be solidified within seconds under UV exposure at room temperature, and the presence of the fluoroalkyl groups in the SSQ resins greatly facilitate mold release after the imprint process. In addition, the absence of metal in the resins makes the materials highly compatible with applications involving Si CMOS integrated circuits fabrication.