164 research outputs found
Efficient Instruction and Data Caching for High Performance Embedded Processors
In the last years, embedded systems have evolved so that they offer capabilities we could only find before in high performance systems. Portable devices already have multiprocessors on-chip (such as PowerPC 476FP or ARM Cortex A9 MP), usually multi-threaded, and a powerful multi-level cache memory hierarchy on-chip. As most of these systems are battery-powered, the power consumption becomes a critical issue. Achieving high performance and low power consumption is a high complexity challenge where some proposals have been already made. Suarez et al. proposed a new cache hierarchy on-chip, the LP-NUCA (Low Power NUCA), which is able to reduce the access latency taking advantage of NUCA (Non-Uniform Cache Architectures) properties. The key points are decoupling the functionality, and utilizing three specialized networks on-chip. This structure has been proved to be efficient for data hierarchies, achieving a good performance and reducing the energy consumption. On the other hand, instruction caches have different requirements and characteristics than data caches, contradicting the low-power embedded systems requirements, especially in SMT (simultaneous multi-threading) environments. We want to study the benefits of utilizing small tiled caches for the instruction hierarchy, so we propose a new design, ID-LP-NUCAs. Thus, we need to re-evaluate completely our previous design in terms of structure design, interconnection networks (including topologies, flow control and routing), content management (with special interest in hardware/software content allocation policies), and structure sharing. In CMP environments (chip multiprocessors) with parallel workloads, coherence plays an important role, and must be taken into consideration
Monolithic integration of Giant Magnetoresistance (GMR) devices onto standard processed CMOS dies
Giant Magnetoresistance (GMR) based technology is nowadays the preferred option for low magnetic fields sensing in disciplines such as biotechnology or microelectronics. Their compatibility with standard CMOS processes is currently investigated as a key point for the development of novel applications, requiring compact electronic readout. In this paper, such compatibility has been experimentally studied with two particular non-dedicated CMOS standards: 0.35 μm from AMS (Austria MicroSystems) and 2.5 μm from CNM (Centre Nacional de Microelectrònica, Barcelona) as representative examples. GMR test devices have been designed and fabricated onto processed chips from both technologies. In order to evaluate so obtained devices, an extended characterization has been carried out including DC magnetic measurements and noise analysis. Moreover, a 2D-FEM (Finite Element Method) model, including the dependence of the GMR device resistance with the magnetic field, has been also developed and simulated. Its potential use as electric current sensors at the integrated circuit level has also been demonstrated
Practical Characterization of Cell-Electrode Electrical Models in Bio-Impedance Assays
This paper presents the fitting process followed to adjust the parameters of the electrical model associated to a cell-electrode system in Electrical Cell-substrate Impedance Spectroscopy (ECIS) technique, to the experimental results from cell-culture assays. A new parameter matching procedure is proposed, under the basis of both, mismatching between electrodes and time-evolution observed in the system response, as consequence of electrode fabrication processes and electrochemical performance of electrode-solution interface, respectively. The obtained results agree with experimental performance, and enable the evaluation of the cell number in a culture, by using the electrical measurements observed at the oscillation parameters in the test circuits employed.Ministerio de EconomÃa y Competitividad TEC2013-46242-C3-1-
Antioxidant activity of isolated compounds in non-volatile residue from orange essential oil
6 páginas, 3 figuras.[ES] Existe un creciente interés en la industria alimentaria y en la medicina
preventiva por la búsqueda de «antioxidantes naturales», por
lo que nos planteamos evaluar la actividad antioxidante del residuo
no volátil del aceite esencial de naranja contra la oxidación del aceite
de oliva sin retinar y de reciente extracción. Mediante destilación
del aceite esencial de naranja se obtuvo el residuo no-volátil, el cual
se fraccionó en columna de silica gel 60. La actividad antioxidante
fue medida por el valor de peróxidos producidos por el aceite de oliva
al provocar la oxidación por calentamiento a 70 °C durante 48 h.
Se aislaron seis compuestos mediante H PLC preparativo de
los cuales cuatro tuvieron actividad antioxidante. Usando métodos
espectroscópicos se identificaron a-tocoferol y tres flavonas
metoxiladas. Con este estudio se confirmó que la fracción no volátil
del aceite esencial de naranja contiene antioxidantes naturales
diferentes al a-tocoferol.[EN] There has been a growing interest in the food industry and in
preventive medicine to search for «natural antioxidants». Therefore
the objetive of this study was to evaluate the antioxidant activity of
the non-volatile residue of essential orange oil in the oxidation of
unrefined and freshly extracted olive oil. Essential orange oil was
distilled to obtain a non-volatile residue and fracctionated on a Silica
Gel 60 column. The antioxidant activity was determined by measuring
peroxide value obtained after heating olive oil at 70 °C for 48 h.
Six compounds were isolated and purified, four of these had
antioxidant activity, a-tocopherol and three methoxylated flavones
were identified using spectroscopic methods. This study confirmed
that non-volatile fractions of essential orange oil contain natural
antioxidants diferent from a-tocopherol.Peer reviewe
Monitoring Muscle Stem Cell Cultures with Impedance Spectroscopy
The aim of this work is to present a new circuit for the real-time monitoring the processes of cellular growth
and differentiation of skeletal myoblast cell cultures. An impedance spectroscopy Oscillation-Based
technique is proposed for the test circuit, converting the biological system into a voltage oscillator, and
avoiding the use of very high performance circuitry or equipment. This technique proved to be successful in
the monitoring of cell cultures growth levels and could be useful for determining the degree of
differentiation achieved, of practical implications in tissue engineering.Ministerio de EconomÃa y Competitividad TEC2013-46242-C3-1-
Software para el aprendizaje de convertidores digitales-analógicos.
Se presenta un paquete de software didáctico que facilita el proceso de enseñanza/
aprendizaje de la electrónica, en concreto, de convertidores digital-analógicos.
Consta de una sección expositiva, en la que se describen los contenidos de la
materia, más un conjunto de simulaciones que permiten al alumno conocer el
funcionamiento interno del convertidor, la evolución de sus parámetros y los
valores intermedios de sus variables durante la ejecución del algoritmo de
conversión D/A. AsÃmismo, se incluye un conjunto tutoriales basados en
animaciones que muestran como se ejecutan las simulaciones, y el funcionamiento
del Convertidor Digital-Analógico (CDA) seleccionado
Characterization of Implanted Stents through Neointimal Tissue Bioimpedance Simulations
This work describes how is possible the definition
of the light hole or lumen in implanted stents affected by
restenosis processes using the BioImpedance (BI) as biomarker.
The main approach is based on the fact that neointimal tissues
implied in restenosis can be detected and measured thanks to
their respective conductivity and dielectric properties. For this
goal, it is proposed a four-electrode setup for bioimpedance
measurement. The influence of the several involved tissues in
restenosis: fat, muscle, fiber, endothelium and blood, have been
studied at several frequencies, validating the setup and
illustrating the sensitivity of each one. Finally, a real example
using a standard stent, has been analyzed for stable and
vulnerable plaques in restenosis test cases, demonstrating that
the proposed method is useful for the stent obstruction test.
Bioimpedance simulation test has been performed using the
electric physics module in COMSOL Multiphysics®.Junta de AndalucÃa 2017/TIC-17
Elevated sea temperature combined with dietary methionine levels affect feed intake and appetite-related neuropeptide expression in the brains of juvenile cobia (Rachycentron canadum)
This study aimed to determine the impact of elevated temperature combined with different levels of dietary methionine concentrations on feed intake (FI) and brain expression of selected neuropeptides and one receptor involved in appetite control in juvenile cobia (approximately 3.7 g body weight). The genes studies were neuropeptide y, npy; agouti-related protein, agrp; cocaine- and amphetamine-regulated transcript, cart; cholecystokinin, cck and melanocortin 4 receptor; mc4r. The cobia were reared at typical sea water temperature in Vietnam (30 degrees C) and elevated temperature (34 degrees C; selected as one of the predicted scenarios of climate change). The fish were fed diets with different levels of methionine: deficient (M9; 9.1 g/kg), sufficient (M12; 12.8 g/kg) and surplus (M16, 16.8 g/kg) for 6 weeks (triplicate tanks per treatment). Both dietary methionine concentration and temperature affected FI in cobia. Dietary methionine deficiency (i.e., M9) and elevated temperature reduced FI in cobia. Temperature significantly influenced the mRNA expression of agrp, cart, cck and mc4r. Expression of the orexigenic neuropeptide npy was consistently higher before the meal than after the meal for all diets and at both temperatures. At 30 degrees C, prefeeding levels of npy correlated with both increased methionine levels and FI. The interaction between dietary methionine and temperature on the levels of brain npy expression was significant (P<0.05). There was higher brain expression of agrp, cart and cck in cobia at 34 degrees C than in fish at 30 degrees C, which was correlated with a lower FI. In conclusion, both feeding, temperature and/or dietary methionine levels affected the brain expression of npy and agrp, cart, cck and mc4r. This suggests that these neuropeptides as well as the mc4r receptor are actively involved in adjusting feed intake to compensate for changing energetic demands, as well as metabolic adjustments due to the variable availability of methionine at elevated temperature.LA/P/0101/2020; QZA-0485 SRV-13/0010info:eu-repo/semantics/publishedVersio
Effect of increased rearing temperature on digestive function in cobia early juvenile
The present study is focused to elucidate the main characteristics of the digestive function of this carnivorous fast-growing fish living at high temperatures. With this aim, we have examined the effects of an increased temperature from 30 to 34 °C on the daily pattern of gastrointestinal pH, enzymatic proteolytic digestive activity and the feed transit time in early juveniles of cobia (Rachycentron canadum), a species living in tropical and subtropical waters with an increasing aquaculture production. Fish were fed two meals a day. Gastric luminal pH was permanently acidic (mean pH values: 2.76-4.74) while the intestinal pH increased from neutral/slightly acidic to slightly alkaline when the digesta was present, with an increasing alkalinity from proximal to distal intestine (mean pH values: 6.05 to 7.69). The temperature did not affect the gastric pH but a slightly higher acidity was induced in the intestine at 34 °C. Pepsin activity showed a daily rhythm at 30 °C with maximum in the middle of the light period, while at 34 °C some hourly changes coinciding with feed adding without a clear daily trend during the 24-h period were observed. The trypsin activity exhibited a daily rhythm at both temperatures with an increase after morning feeding to reach a maximum several hours later. Average pepsin activity during the daily cycle was slightly higher at 34 °C (6.1 and 7.3 U mg-1 BW at 30 and 34 °C respectively), but values were significantly different only at 8 and 24 h after the morning meal. Similarly, the trypsin activity was significantly affected by the temperature only at 8 and 16 h after the morning meal, but daily activity averages were similar (1.20 and 1.29 U g-1 BW at 30 and 34 °C respectively). The partial transit rates of the first meal in the stomach for each period inter-samplings were higher during the first 4-h period and decreased progressively along the rest of the 24-h cycle at both temperatures, but no significant differences were detected at 30 °C. In addition, the transit was notably faster at 34 °C particularly during the first 8 h after feeding, with rates between 100 and 65% of total volume displaced (intake or released) during each 4-h period. In the intestine the transit rate was relatively constant and similar at both temperatures during 12 h after feeding. Then the rates remained very low during the following 12 h. Residence time of the first meal was longer at 30 than at 34 °C, particularly in the stomach (12 h:02 min vs 4 h:54 min respectively). In the intestine the difference was not so large (8 h:18 min vs 6 h:24 min respectively). In a parallel study under same conditions, cobia reared at 30 °C grew faster and showed a more favorable feed conversion ratio than those at elevated temperature (34 °C). The present results indicate that at 34 °C, a subtle increase of proteolytic activity cannot compensate for the faster gut transit rate. Therefore, 30 °C is more appropriate temperature for the early on-growing of cobia because at higher temperatures the digestion efficiency decrease being one of the causes for a lower growth.Agência financiadora
European Union (EU)
691150
MINECO, Spain + FEDER/ERDF contribution
EFISHDIGESTAGL2014-52888
European Social Fund, the Operational Programme Human Potential
IF/00482/2014/CP1217/CT0005
Portuguese Foundation for Science and Technology
Portuguese Foundation for Science and Technology
UDI/Multi/04326/2013
Norwegian Agency for Development Cooperation NORHED
QZA-0485 SRV-13/0010info:eu-repo/semantics/publishedVersio
Oscillation-Based Spectroscopy for Cell-Culture Monitorization
Biological Impedance is a physical property related to the state and inherent evolution of biological samples. Among the existing impedance measurement methods, Oscillation-Based (OB) tests are a simple and smart solution to indirectly measure impedance correlated with the amplitude and frequency of the generated oscillation which are proportional to the sample under test. An OB test requires tuning of the system blocks to specifications derived from every measurement problem. The OB setup must be done to obtain the optimum measurement sensitivity for the specific constraints imposed by the system under test, electronic interfaces, and electrodes employed for test. This work proposes the extension of OB measurement systems to spectroscopy test, enabling a completely new range of applications for this technology without the restrictions imposed by setting a fixed frequency on the electrical oscillator. Some examples will be presented to the measurement of cell cultures samples, considering the corresponding circuit interfaces and electric models for the electrode-cell system. The proposed analysis method allows the selection of the best oscillator elements for optimum sensitivity range in amplitude and frequency oscillation values, when a specific cell culture is monitored for the OB system
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