TRAIL: A novel atheroprotective mechanism in the vasculature

The vasculature is critical for the maintenance of cardiovascular homeostasis. Cardiovascular disease (CVD) is characterised by endothelial cell (EC) and vascular smooth muscle cell (VSMC) dysfunction, in which vascular oxidative stress is a primary cause. The mechanisms and stimuli involved in vascular dysfunction are not fully characterised. Our lab showed that TNF-related apoptosis-inducing ligand (TRAIL) is a master regulator of vascular cell function, and its deletion in Apoe-/- mice accelerated atherosclerosis and CVD. TRAIL is increasingly recognised to play a protective role in CVD, however, how it may regulate vascular function is unclear. This thesis aimed to investigate TRAIL’s protective role against oxidative stress resulting in CVDs. It studied TRAIL’s role in clinical, pre-clinical and in-vitro models. This thesis also aimed to elucidate the mechanism of action of TRAIL in vascular cells in vivo using cell-specific TRAIL knockout mouse models under normal and pathological conditions. This thesis demonstrated that: i. Circulating plasma TRAIL and oxidative stress markers are negatively correlated in patients with coronary artery disease (CAD). ii. Following high fat diet (HFD), mice lacking TRAIL had endothelial dysfunction, vascular inflammation and increased vessel permeability. iii. TRAIL protected against angiotensin II (AngII)-induced oxidative stress in vitro in ECs. TRAIL also negated AngII-induced cell processes by reducing monocyte adhesion and improving permeability in-vitro in ECs. iv. EC-specific TRAIL deleted mice challenged with an HFD, experienced high plasma cholesterol, reduced blood pressure and altered gene expression profiles for inflammatory markers compared to wild type mice. v. VSMC-specific TRAIL deleted mice challenged with an HFD, displayed altered expression of genes regulating VSMC phenotype. These mice also had an enlarged liver compared to wild type mice in response to an HFD. This thesis provided novel insight into the protective role of TRAIL against endothelial dysfunction via its ability to modulate oxidative stress. This thesis studied the mechanism of action of TRAIL in vascular cells. Thus, understanding the role TRAIL plays in normal physiology and disease, may lead to potential new therapies to improve vascular functions and CVDs

Multiwavelength fiber laser based on bidirectional lyot filter in conjunction with intensity dependent loss mechanism

We experimentally demonstrate a multiwavelength fiber laser (MWFL) based on bidirectional Lyot filter. A semiconductor optical amplifier (SOA) is used as the gain medium, while its combination with polarization controllers (PCs) and polarization beam combiner (PBC) induces intensity dependent loss (IDL) mechanism. The IDL mechanism acts as an intensity equalizer to flatten the multiwavelength spectrum, which can be obtained at a certain polarization state. Using different ratio of optical splitter has affected to multiwavelength flatness degradation. Subsequently, when we removed a polarizer in the setup, the extinction ratio (ER) is decreased. Ultimately, with two segments of polarization maintaining fiber (PMF), two channel spacings can be achieved due to splicing shift of 0° and 90°

Improvement of optical signal-to-noise ratio of a high-power pump by stimulated Brillouin scattering in an optical fiber

We propose and demonstrate improvement of optical signal-to-noise ratio of a highpower pump by saturated stimulated Brillouin amplification of a backward seed in a fiber. A 27-dB improvement was obtained for a 1-W pump

Four-wave mixing cascades seeded by a multiwavelength Brillouin–erbium fiber laser

Four-wave mixing (FWM) cascades which are seeded by a multiwavelength Brillouin–erbium fiber laser (MBEFL) are experimentally demonstrated in this work. The MBEFL, which is based on virtual mirror feedback, is successful in providing the seed for the FWM cascades. The stimulated Brillouin scattering and parametric gain for the development of the MBEFL and FWM cascades, respectively, are provided by a 12 km dispersion-shifted fiber (DSF). By launching the MBEFL into the DSF, as many as 80 comb lines can be generated when the Brillouin pump (BP) wavelength is tuned at 1560 nm. Analysis of FWM cascades as a function of BP wavelength shows that the number of comb lines is greater at the anomalous-dispersion region of the DSF, suggesting that the phase mismatch is minimized in that regime

Antibioticoterapia versus apendicetomía en apendicitis aguda no complicada: Una revisión sistemática y metaanálisis

Determinar si la antibioticoterapia tiene mayor eficacia que la apendicectomía en adultos con apendicitis aguda no complicada. Materiales y métodos: Se realizó una revisión sistemática y metaanálisis, se incluyó seis ensayos clínicos que comparan la antibioticoterapia versus apendicectomía en resolución definitiva de la clínica durante el periodo de hospitalización inicial. Asimismo, se evaluó los siguientes desenlaces: recurrencia de la apendicitis, complicaciones mayores y duración de la estancia hospitalaria. Resultados: La probabilidad de presentar una mejoría clínica definitiva en el grupo que recibió antibioticoterapia fue 5% menor con respecto al grupo que fue sometido a una apendicectomía (RR 0.5; IC95% 0.92-0.98; p= 0.004; IC2=44%). La probabilidad de presentar una recurrencia de la apendicitis en el grupo que recibió antibioticoterapia fue 99.86 veces la del grupo que fue sometido a una apendicectomía (RR 94.86; IC95% 30.73-292.81; p< 0.00001; IC2=0%). En lo que respecta a las complicaciones mayores, la probabilidad de presentar una en el grupo que recibió antibioticoterapia fue 45% menor con respecto al grupo que fue sometido a una apendicectomía (RR 0.55; IC95% 0.36-0.85; p=0.007; IC2=0%). Finalmente, la media de la duración de la estancia hospitalaria en aquellos que recibieron antibioticoterapia fue 0.34 desviaciones estándar más en comparación a aquellos pacientes que fueron sometidos a una apendicectomía (MD 0.34; IC95% 0.25-0.42; p<0.00001; IC2= 64%). Conclusiones: La antibioticoterapia presenta una menor eficacia que la apendicectomía en adultos con apendicitis aguda no complicada.To determine if antibiotic therapy is more effective than appendectomy in adults with uncomplicated acute appendicitis. Methods: A systematic review and meta-analysis were performed, including six clinical trials that compare antibiotic therapy versus appendectomy in definitive resolution of the symptoms during the initial hospitalization period. Likewise, the following outcomes were assessed: recurrence of appendicitis, major complications, and length of hospital stay. Results: The incidence of presenting a definitive clinical improvement in the group that received antibiotic therapy was 5% lower compared to the group that underwent an appendectomy (RR 0.5; 95%CI 0.92-0.98; p= 0.004; CI2=44%). The incidence of presenting a recurrence of appendicitis in the group that received antibiotic therapy was 94.86 times that of the group that underwent appendectomy (RR 94.86; 95%CI 30.73-292.81; p<0.00001; CI2=0%). Regarding major complications, the incidence of presenting one in the group that received antibiotic therapy was 45% lower compared to the group that underwent appendectomy (RR 0.55; 95%CI 0.36-0.85; p=0.007; CI2= 0%). Finally, the mean length of hospital stay in those who received antibiotic therapy was 0.34 standard deviations more compared to those patients who underwent appendectomy (MD 0.34; 95%CI 0.25-0.42; p<0.00001; CI2= 64% ). Conclusions: Antibiotic therapy is less effective than appendectomy in adults with uncomplicated acute appendicitisTesi

Dual-wavelength thulium fluoride fiber laser based on SMF-TMSIF-SMF interferometer as potential source for microwave generationin 100-GHz region

A dual-wavelength thulium-doped fluoride fiber (TDFF) laser is presented. The generation of the TDFF laser is achieved with the incorporation of a single modemultimode- single mode (SMS) interferometer in the laser cavity. The simple SMS interferometer is fabricated using the combination of two-mode step index fiber and single-mode fiber. With this proposed design, as many as eight stable laser lines are experimentally demonstrated. Moreover, when a tunable bandpass filter is inserted in the laser cavity, a dual-wavelength TDFF laser can be achieved in a 1.5-μm region. By heterodyning the dual-wavelength laser, simulation results suggest that the generated microwave signals can be tuned from 105.678 to 106.524 GHz with a constant step of �0.14 GHz. The presented photonics-based microwave generation method could provide alternative solution for 5G signal sources in 100-GHz region

Efecto del porcentaje de humedad y temperatura de tratamiento en las características físicas y propiedades térmicas de almidón de papa (solanum tuberosum L.) modificado (HMT) var. colparina

El objetivo de esta investigación fue evaluar el efecto del porcentaje de humedad y la temperatura de tratamiento en las características físicas (tamaño de los gránulos, poder de hinchamiento y solubilidad) y propiedades térmicas (temperatura y entalpía de gelatinización, porcentaje de gelatinización) de almidón de papa modificado. Para elaborar las muestras de almidón modificado (HMT) se ajustó el contenido de humedad del almidón nativo al nivel deseado (20%, 30% y 40%). Posteriormente, las muestras de almidón se colocaron en frascos de vidrio de 250 mL y se calentaron a 100, 110 y 120 ºC durante 8 h, luego se envasaron en frascos de vidrio de 250 mL y se almacenaron a temperatura ambiente para su posterior análisis. El almidón nativo se utilizó como un control. El análisis estadístico informó que el porcentaje de humedad (20, 30 y 40 % p/p) y la temperatura de tratamiento (100, 110 y 120 °C) tuvieron efecto significativo en el tamaño del gránulo, poder de hinchamiento y propiedades térmicas (temperatura, entalpía y porcentaje de gelatinización) de almidón de papa modificado (HMT) variedad Colparina. El tratamiento T9 de modificación de almidón HMT (40%; 120 ºC) presentó menor poder de hinchamiento y solubilidad, mayor valor de temperatura inicial, pico y final de gelatinización, menor entalpía y mayor grado de gelatinización, por lo que podría recomendarse su aplicación en la formulación de alimentos envasados, congelados, fideos y productos de panificación, como extensor de grasa, para aumentar el contenido de fibra dietética de los alimentos o para preparar películas biodegradables.The objective of this research was to evaluate the effect of moisture percentage and treatment temperature on the physical characteristics (granule size, swelling power and solubility) and thermal properties (gelatinization temperature and enthalpy, percentage of gelatinization) of modified potato starch. To prepare the modified starch samples (HMT), the moisture content of the native starch was adjusted to the desired level (20%, 30% and 40%). The starch samples were then placed in 250 mL glass vials and heated to 100, 110 and 120 ° C for 8 h, then packed in 250 mL glass vials and stored at room temperature for further analysis. Native starch was used as a control. Statistical analysis reported that the percentage of moisture (20, 30 and 40% w / w) and the treatment temperature (100, 110 and 120 ° C) had a significant effect on the size of the granule, swelling power and termic properties (temperature, enthalpy and percentage of gelatinization) of modified potato starch (HMT) Colparina variety. The T9 treatment of HMT starch modification (40%, 120 °C) showed lower swelling and solubility, higher initial , peak and final gelatinization temperature of , lower enthalpy and higher gelatinization grade, and therefore its application in the formulation of packaged, frozen, noodles and bakery products, such as fat extender, to increase the dietary fiber content of foods or to prepare biodegradable films

Estimación del espesor óptico de los aerosoles a partir de los datos Level 1B del sensor MODIS sobre Perú (2004 - 2005)

Estima el espesor óptico de los aerosoles (⅄c =0,55 µm) a una resolución espacial de 1 km x 1 km, usando el modelo de transferencia radiativa Santa Barbara DISORT Atmospheric Radiative Transfer (SBDART) (Ricchiazzi y Yang, 1998). Este modelo simula la transferencia radiativa en la atmósfera (scattering, absorción, emisión, etc), la interacción de la radiación tanto solar como terrestre con los componentes atmosféricos como el vapor de agua, dióxido de carbono, metano, etc. El modelo SBDART, genera un archivo de salida ASCII, que contiene la irradiancia en el tope de la atmosfera y en la superficie terrestre, obtenido mediante la aproximación de dos flujos y la aproximación de Eddington para resolver la ecuación de transferencia radiativa, considerando una atmosfera plano paralela. Para luego generar las ecuaciones definidas por el espesor óptico de los aerosoles (⅄c =0,55 µm) en función de la reflectancia en el tope de la atmosfera, mediante una regresión polinomial de grado 3, para la banda 1 (⅄c =0,66 µm) del sensor MODIS, con diferentes valores de espesor óptico de los aerosoles (⅄c =0,55 µm) y otras condiciones (geometría del Sol y del Sensor, un modelo de aerosoles y la reflectancia de la superficie (⅄c =0,66 µm). El área de estudio es el espacio aéreo de Perú, que se encuentra entre las latitudes 0002′00"S a 18021′03"S y las longitudes de 68039′00"O a 81019′35"O. Para el tratamiento de las imágenes MODIS Level 1B, se usa el lenguaje de programación IDL versión 7.8. Luego, usando los resultados del Modelo SBDART se calcula el promedio anual del espesor óptico de los aerosoles (⅄c =0,55 µm) a una resolución espacial de 1 km x 1 km en todo el área de estudio, para los años 2004 y 2005, con valores que oscilan entre 0,1 y 1,0, así como para la región amazónica tanto para el año 2004 y 2005, coincidiendo los valores máximos del espesor óptico de los aerosoles con el tiempo de inicio de los incendios forestales en Brasil.Tesi

Two-pump parametric amplification in the presence of fiber dispersion fluctuations: a comparative study

Fiber optical parametric amplifiers (FOPAs) operating based on four-wave mixing (FWM) are versatile devices with increasing applications in optical communication systems. In this paper, the effects of dispersion fluctu�ations on the performance of bandwidth, ripple, parametric gain, and saturation power of a two-pump FOPA based on four-wave and six-wave models are studied and compared. Coupled-amplitude equations representing the non-degenerate FWM process in optical fiber are solved numerically to compute the parametric gain over the communication wavelengths. The behaviors of the performance parameters are critically analyzed and compared with different types of fluctuation strengths (or amplitudes) specified by the combinations of correlation length (Lc) and fluctuation amplitude (σ). Based on the results, it was found that the flat gain bandwidth for the four-wave model remains unchanged and is insensitive to the strengths of fluctuations. The gain ripples, however, get higher as the fluctuation strengths increase. On the other hand, the flat gain bandwidths of the six-wave model are hardly identified due to the tremendous and continuous ripples within the pump wavelengths. In addition, the minimum parametric gain values for both four-wave and six-wave models reduce as the fluctuation strengths increase. Also, the lowest value of parametric gain leads to the highest saturation power and vice versa. The dispersion fluctuations affect the FWM process’s efficiency and deteriorate the overall amplifier performance, particularly for the six-wave model. The numerical analysis obtained via the six-wave model is especially useful since this model closely matches with practical circumstances

Stable multiwavelength erbium-doped random fiber laser

A stable multiwavelength erbium-doped fiber laser (EDFL) based on random distributed feedback (RDFB) is presented. The random EDFL consists of a half-opened linear cavity in which a mirror forms one end, while the other end is connected to RDFB of a 25-km-long single mode fiber. In the laser cavity, the instability caused by the RDFB and cascaded stimulated Brillouin scattering is successfully mitigated by four wave mixing effect in a 2-km-long highly nonlinear fiber. Experimental results indicate the generation of 24 stable laser lines at the pump power of 350 mW. The recorded peak power fluctuation for the laser is less than 0.7 dB in a 60-min duration, illustrating the stability of the multiwavelength random fiber laser