Revisiting alcohol dehydrogenases: Self-sufficient regio- and enantio- selective formation of bi- and tri-cyclic lactones

The field of biocatalysis has witnessed over the past few years a renewed interest in the design of synthetic routes with high atom-economy, particularly of those employing redox enzymes. For long, the implementation of efficient recycling systems for cofactors (typically nicotinamide) essential to these enzymes was considered attractive for economical reasons, since the use of co-substrate and co-enzyme approaches [1] usually implied co-conversion of a cheap auxiliary substrate (e.g., glucose, ethanol, acetone, formate). In line with growing awareness for sustainable technologies and the desire to reduce the environmental footprint of synthetic processes, strategies that bypass the need for stoichiometric amounts of co-subtrate or reagents are now being considered. For redox enzymes, this translates for instance into the enlargement of the scope of intramolecular hydride transfer, which allows biotransformations to run in closed loop. Exemplary are redox isomerization reactions applied to allylic alcohols or recently cyclic hydroxy-ketones [2]. In both cases, no new bond is created, and the hydride shift is responsible for a switch of functionality. Owing to the dual redox reactivity of aldehydes and complementary activity of alcohol dehydrogenases (ADHs) on the aldehyde functionality (oxidation/reduction), a formal intramolecular biocatalytic hydride shift can be considered with dialdehyde molecules. Following our work on the disproporationation of aldehydes and the establishment of a biocatalytic Cannizzaro-type reaction using ADHs [3], we are now disclosing a broadly applicable enzymatic platform for the synthesis of bi- and tri-cyclic lactones starting from dialdehydes (Scheme 1). An intramolecular bio-Tishchenko reaction was developed with particular attention to redox economy. High turn-over numbers for the nicotinamide cofactor (up to 1.6x103 half-reactions) along with efficient 1,4-, 1,5- and 1,6-hydride shift on dialdehydes (1:1 ratio enzyme/cofactor) could be demonstrated, following reduction-oxidation sequence through lactol intermediate. Noteworthy, regio- and enantioselectivity were observed with a range of wild-type and engineered ADHs and preparative scale synthesis allowed isolation of several lactone products, with no concomitant waste generation [4]. Application of these lactones in (cross-)polymerization reactions is currently being investigated. Please click Additional Files below to see the full abstract

Design and implementation of an attitude determination and control system for the AntelSat

This thesis describes the design, analysis and construction of the Attitude Determination and Control System (ADCS) for the first Uruguayan nanosatellite, the AntelSat. The AntelSat project is a joint venture between the Electrical Engineering Institute (IIE) of Faculty of Engineering, Universidad de la República (UdelaR University) and Antel, the Uruguayan national telecommunications company. The satellite consists of a two-unit (2U) CubeSat, which implies that the ADCS is designed under tight mass, size, and energy constraints. In addition, these kind of satellites usually have limited sensing, computational and communication capabilities, motivating the need for autonomous and computationally eficient algorithms. Under these strict restraints, developing an effective attitude control system poses a significant challenge. As presented in this thesis, for the attitude determination section of the ADCS, data available from sensors is taken as inputs for the computation of an optimal quaternion estimator. The use of a quaternion implementation of an unscented Kalman filter is also discussed. Additionally, attitude control is based on magnetic actuation with magnetorquers being commanded by pulse width modulation. It is shown that the control system is able to achieve the detumbling of the satellite after separation from the launch interface using the reliable B-dot control law. Nadirpointing control is achieved with the use of a simple Linear Quadratic Regulator. Also pertinent is the simulation environment that was implemented to develop the attitude determination and control algorithms and also to validate their performance. ADCS hardware prototypes and flight versions that were designed and constructed are introduced.Este documento de tesis describe el diseño, análisis y construcción de el Sistema de Determinación y Control de Actitud (ADCS por sus siglas en inglés) del primer satélite uruguayo, el AntelSat. El proyecto AntelSat es una actividad conjunta entre el Instituto de Ingeniería Eléctrica (IIE) de la Facultad de Ingeniería de la Universidad de la República y Antel, la empresa de telecomunicaciones nacional de Uruguay. El satélite consiste en un CubeSat de dos unidades (2U), lo que implica que el ADCS es diseñado bajo estrictas restricciones de masa, tamaño y energía. Además, este tipo de satélites posee una capacidad computacional, de comunicaciones y de medición limitada, lo que motiva la necesidad de lograr algoritmos computacionalmente eficientes. Bajo estas estrictas limitaciones, el desarrollo de un sistema de control de actitud efectivo se traduce en un reto importante. Como se presenta en esta tesis, para el segmento de determinación de actitud del ADCS, la información proveniente de los sensores es tomada como entrada para el cálculo de un estimador de cuaternión óptimo. Se discute también el uso de una implementación con cuaterniones de un filtro de Kalman "unscented". Por otro lado, el control de actitud está basado en actuación magnética con magnetorquers comandados con modulación de ancho de pulso. Se demuestra que el sistema de control es capaz de reducir el valor de velocidad angular del satélite en la fase previa a la separación con la interfaz de lanzamiento, mediante la utilización del algoritmo B-dot. La estabilización de la actitud en modo de apunte al nadir se logra con el uso de un simple regulador lineal cuadrático. Por otra parte, se presenta el entorno de simulación que fue implementado para el desarrollo de algoritmos de determinación y control de actitud, y también para validar el desempeño de los mismos. A su vez, se exhiben el hardware del ADCS que fue diseñado y construido, tanto prototipos como versiones de vuelo

FastDVDnet: Towards Real-Time Video Denoising Without Explicit Motion Estimation

In this paper, we propose a state-of-the-art video denoising algorithm based on a convolutional neural network architecture. Until recently, video denoising with neural networks had been a largely under explored domain, and existing methods could not compete with the performance of the best patch-based methods. The approach we introduce in this paper, called FastDVDnet, shows similar or better performance than other state-of-the-art competitors with significantly lower computing times. In contrast to other existing neural network denoisers, our algorithm exhibits several desirable properties such as fast run-times, and the ability to handle a wide range of noise levels with a single network model. The characteristics of its architecture make it possible to avoid using a costly motion compensation stage while achieving excellent performance. The combination between its denoising performance and lower computational load makes this algorithm attractive for practical denoising applications. We compare our method with different state-of-art algorithms, both visually and with respect to objective quality metrics

Polyether Plant Design

In recent years, the global market for polyethers has seen rapid expansion due to the growth of the construction, automobile, and foam industries. Polyethers are principally sold to polyurethane plants to produce a wide range of flexible and rigid foams that are used in a wide range of applications from automotive upholstery to inks. Consequently, the process for manufacturing polyethers is extremely vital to the consumer goods market and for maintaining the quality of life to which many people have grown accustomed. In this report, a plant has been designed in the Asia-Pacific region to produce 100 million pounds of a 3,000 g/mol polyether polymer per year. The process consists of five main steps: reaction, initiation, addition of propylene oxide (PO), elongation of the growing polymer chain, purification of polyether, and stabilization of polyether. The key features in this process design include a pre-reactor for activating our glycerin initiator, two reactor vessels in series for the polymerization, and a continuous gravity decanter catalyst removal system. Multiple safety features were also implemented, including vessel purging and pressurized reactors to avoid leaks and keep PO in the liquid phase. Ultimately, our design produces three batches per day of 101,000 lbs of polyether for 330 operating days. Finally, using a three-pass water wash with 90% catalyst removal in each pass, the final purity of our polyether with respect to potassium is 0.9 ppm. The profitability analysis for the current design estimates an NPV of $30,378,100 and an IRR of 53.40%. The return on investment is 51.01%. Sensitivity analyses to operating cost and profit showed that the plant is robust even amidst market fluctuations, and the project is a profitable endeavor

DVDnet: A Fast Network for Deep Video Denoising

In this paper, we propose a state-of-the-art video denoising algorithm based on a convolutional neural network architecture. Previous neural network based approaches to video denoising have been unsuccessful as their performance cannot compete with the performance of patch-based methods. However, our approach outperforms other patch-based competitors with significantly lower computing times. In contrast to other existing neural network denoisers, our algorithm exhibits several desirable properties such as a small memory footprint, and the ability to handle a wide range of noise levels with a single network model. The combination between its denoising performance and lower computational load makes this algorithm attractive for practical denoising applications. We compare our method with different state-of-art algorithms, both visually and with respect to objective quality metrics. The experiments show that our algorithm compares favorably to other state-of-art methods. Video examples, code and models are publicly available at \url{https://github.com/m-tassano/dvdnet}

Deep Model-Based Super-Resolution with Non-uniform Blur

We propose a state-of-the-art method for super-resolution with non-uniform blur. Single-image super-resolution methods seek to restore a high-resolution image from blurred, subsampled, and noisy measurements. Despite their impressive performance, existing techniques usually assume a uniform blur kernel. Hence, these techniques do not generalize well to the more general case of non-uniform blur. Instead, in this paper, we address the more realistic and computationally challenging case of spatially-varying blur. To this end, we first propose a fast deep plug-and-play algorithm, based on linearized ADMM splitting techniques, which can solve the super-resolution problem with spatially-varying blur. Second, we unfold our iterative algorithm into a single network and train it end-to-end. In this way, we overcome the intricacy of manually tuning the parameters involved in the optimization scheme. Our algorithm presents remarkable performance and generalizes well after a single training to a large family of spatially-varying blur kernels, noise levels and scale factors

Confronto tra parecoxib e robenacoxib per il trattamento del dolore postoperatorio nel cane

Premessa: l’obiettivo di questo studio è stato quello di valutare l’efficacia e la tollerabilità del parecoxib (Dynastat®), un inibitore altamente selettivo della COX-2 (per uso umano), per il trattamento del dolore postoperatorio nei cani. Materiali e metodi: il parecoxib è stato comparato al robenacoxib (Onsior®), un COXIB per uso veterinario, in uno studio clinico prospettivo, randomizzato e in doppio cieco. Sono stati inclusi nello studio 21 cani sottoposti ad ovariectomia laparoscopica suddivisi in 3 gruppi, in modo casuale, per ricevere rispettivamente singole dosi di parecoxib (2 mg/kg, n=7) GPX, robenacoxib (2 mg/kg, n=7) GRX o morfina (0,3 mg/kg, n=7) GMORF (gruppo di controllo positivo), per via intramuscolare, 5 minuti prima dell’induzione dell’anestesia. Il dolore post-operatorio è stato valutato ogni ora fino alle 24h successive al risveglio mediante l’uso della Glasgow short form pain scale. In caso di punteggio superiore a 6 era prevista una rescue analgesia con morfina ad un dosaggio di 0,3 mg/kg. Risultati: il valore medio massimo registrato nel punteggio del dolore è stato di 3 nel GPX, di 5 nel GRX e di 3 nel GMORF. Nel GMORF il dosaggio medio di morfina nel periodo postoperatorio è stato di 0,9 mg/kg nelle 24h. Nessuno dei cani del GPX e del GRX ha richiesto una rescue analgesia nel postoperatorio. In tutti i gruppi è stato osservato un 25-50% di nausea e scialorrea. Conclusioni: nel postoperatorio sia il robenacoxib che il parecoxib hanno assicurato una buona efficacia analgesica nelle 24h. Gli effetti collaterali registrati hanno avuto un’incidenza simile nei tre gruppi; infatti la nausea e il vomito sono riportati come effetti collaterali della chirurgia laparoscopic

Abogados conversando con docentes sobre <i>bullying</i>, cortito y al pie

Reseña del libro Bullying: responsabilidades y aspectos legales en la convivencia escolar compilado por Juan Antonio Seda, Noveduc, 2014. Plantea qué es el bullying, cómo se reconoce legalmente y luego empieza a recorrer aspectos del tema en el contexto escolar.Facultad de Ciencias Jurídicas y Sociale

Abogados conversando con docentes sobre <i>bullying</i>, cortito y al pie

Reseña del libro Bullying: responsabilidades y aspectos legales en la convivencia escolar compilado por Juan Antonio Seda, Noveduc, 2014. Plantea qué es el bullying, cómo se reconoce legalmente y luego empieza a recorrer aspectos del tema en el contexto escolar.Facultad de Ciencias Jurídicas y Sociale