1,163 research outputs found

    A power efficient 2Gb/s transceiver in 90nm CMOS for 10mm On-Chip interconnect

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    Global on-chip data communication is becoming a concern as the gap between transistor speed and interconnect bandwidth increases with CMOS process scaling. In this paper a low-swing transceiver for 10mm long 0.54μm wide on-chip interconnect is presented, which achieves a similar data rate as previous designs (a few Gb/s), but at much lower power than recently published work. Both low static power and low dynamic power (low energy per bit) is aimed for. A capacitive pre-emphasis transmitter lowers the voltage swing and increases the bandwidth using a simple inverter based transceiver and capacitive coupling to the interconnect. The receiver uses Decision Feedback Equalization with a power-efficient continuous-time feedback filter. A low power latch-type voltage sense amplifier is used. The transceiver, fabricated in a 1.2V 90nm CMOS process, achieves 2Gb/s. It consumes only 0.28pJ/b, which is 7 times lower than earlier work

    Low-Power, High-Speed Transceivers for Network-on-Chip Communication

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    Networks on chips (NoCs) are becoming popular as they provide a solution for the interconnection problems on large integrated circuits (ICs). But even in a NoC, link-power can become unacceptably high and data rates are limited when conventional data transceivers are used. In this paper, we present a low-power, high-speed source-synchronous link transceiver which enables a factor 3.3 reduction in link power together with an 80% increase in data-rate. A low-swing capacitive pre-emphasis transmitter in combination with a double-tail sense-amplifier enable speeds in excess of 9 Gb/s over a 2 mm twisted differential interconnect, while consuming only 130 fJ/transition without the need for an additional supply. Multiple transceivers can be connected back-to-back to create a source-synchronous transceiver-chain with a wave-pipelined clock, operating with 6sigma offset reliability at 5 Gb/s

    Type 2 diabetes mellitus and skeletal muscle metabolic function.

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    AB - Type 2 diabetic patients are characterized by a decreased fat oxidative capacity and high levels of circulating free fatty acids (FFAs). The latter is known to cause insulin resistance, in particularly in skeletal muscle, by reducing insulin stimulated glucose uptake, most likely via accumulation of lipid inside the muscle cell. A reduced skeletal muscle oxidative capacity can exaggerate this. Furthermore, type 2 diabetes is associated with impaired metabolic flexibility, i.e. an impaired switching from fatty acid to glucose oxidation in response to insulin. Thus, a reduced fat oxidative capacity and metabolic inflexibility are important components of skeletal muscle insulin resistance. The cause of these derangements in skeletal muscle of type 2 diabetic patients remains to be elucidated. An impaired mitochondrial function is a likely candidate. Evidence from both in vivo and ex vivo studies supports the idea that an impaired skeletal muscle mitochondrial function is related to the development of insulin resistance and type 2 diabetes mellitus. A decreased mitochondrial oxidative capacity in skeletal muscle was revealed in diabetic patients, using in vivo 31-Phosphorus Magnetic Resonance Spectroscopy (31P-MRS). However, quantification of mitochondrial function using ex vivo high-resolution respirometry revealed opposite results. Future (human) studies should challenge this concept of impaired mitochondrial function underlying metabolic defects and prove if mitochondria are truly functional impaired in insulin resistance, or low in number, and whether it represents the primary starting point of pathogenesis of insulin resistance, or is just an other feature of the insulin resistant stat

    Determination of antioxidant activity of polyphenol extract from grape seeds

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    The significance of carbohydrates for endurance training has been well established, whereas the role of protein and the adaptive response with endurance training is unclear. Therefore, the aim of this perspective is to discuss the current evidence on the role of dietary protein and the adaptive response with endurance training. On a metabolic level, a single bout of endurance training stimulates the oxidation of several amino acids. Although the amount of amino acids as part of total energy expenditure during exercise is relatively low compared to other substrates (e.g., carbohydrates and fat), it may depress the rates of skeletal muscle protein synthesis, and thereby have a negative effect on training adaptation. A low supply of amino acids relative to that of carbohydrates may also have negative effects on the synthesis of capillaries, synthesis and turn-over of mitochondrial proteins and proteins involved in oxygen transport including hamoglobin and myoglobin. Thus far, the scientific evidence demonstrating the significance of dietary protein is mainly derived from research with resistance exercise training regimes. This is not surprising since the general paradigm states that endurance training has insignificant effects on skeletal muscle growth. This could have resulted in an underappreciation of the role of dietary protein for the endurance athlete. To conclude, evidence of the role of protein on endurance training adaptations and performance remains scarce and is mainly derived from acute exercise studies. Therefore, future human intervention studies must unravel whether dietary protein is truly capable of augmenting endurance training adaptations and ultimately performance

    Evidence for multiple steps in the pre-steady-state electron transfer reaction of nitrogenase from Azotobacter vinelandii

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    AbstractThe effect of the NaCl concentration and the reaction temperature on the MgATP-dependent pre-steady-state electron transfer reaction (from the Fe protein to the MoFe protein) of nitrogenase from Azotobacter vinelandii was studied by stopped-flow spectrophotometry and rapid-freeze EPR spectroscopy. Besides lowering the reaction temperature, also the addition of NaCl decreased the observed rate constant and the amplitude of the absorbance increase (at 430 nm) which accompanies pre-steady-state electron transfer. The diminished absorbance increase observed at 5°C (without NaCl) can be explained by assuming reversible electron transfer, which was revealed by rapid-freeze EPR experiments that indicated an incomplete reduction of the FeMo cofactor. This was not the case with the salt-induced decrease of the amplitude of the stopped-flow signal: the observed absorbance amplitude of the electron transfer reaction predicted only 35% reduction of the MoFe protein, whereas rapid-freeze EPR showed 80% reduction of the FeMo cofactor. In the presence of salt, the kinetics of the reduction of the FeMo cofactor showed a lag period which was not observed in the absorbance changes. It is proposed that the pre-steady-state electron transfer reaction is not a single reaction but consists of two steps: electron transfer from the Fe protein to a still unidentified site on the MoFe protein, followed by the reduction of the FeMo cofactor. The consequences of our finding that the pre-steady-state FeMo cofactor reduction does not correlate with the amplitude and kinetics of the pre-steady-state absorbance increase will be discussed with respect to the present model of the kinetic cycle of nitrogenase

    A High-Efficiency 4x45W Car Audio Power Amplifier using Load Current Sharing

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    A 4x45W (EIAJ) monolithic car audio power amplifier is presented that achieves a power dissipation decrease of nearly 2x over standard class AB operation by sharing load currents between loudspeakers. Output signals are conditioned using a common-mode control loop to allow switch placement between loads with minimal THD increase. A prototype is realized in a SOI bipolar-CMOS-DMOS process with 0.5μm feature size. Die area is 7.5x4.6mm2. THD+N @(1kHz,10W) is 0.05%

    Optimal Positions of Twists in Global On-Chip Differential Interconnects

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    Abstract—Crosstalk limits the achievable data rate of global on-chip interconnects on large CMOS ICs. This is especially the case, if low-swing signaling is used to reduce power consumption. Differential interconnects provide a solution for most crosstalk and noise sources, but not for neighbor-to-neighbor crosstalk in a data bus. This neighbor-to-neighbor crosstalk can be reduced with twists in the differential interconnect-pairs. To reduce via resistance and metal layer use, we use as few twists as possible by placing only one twist in every even interconnect-pair and only two twists in every odd interconnect-pair. Analysis shows that there are optimal positions for the twists, which depend on the termination impedances of the interconnects. Theory and measurements on a 10 mm long bus in 0.13 μm CMOS show that only one twist at 50% of the even interconnect-pairs, two twists at 30% and 70% of the odd interconnect-pairs and both a low-ohmic source and a low-ohmic load impedance are very effective in mitigating the crosstalk

    COSTA: Co-Occurrence Statistics for Zero-Shot Classification

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    In this paper we aim for zero-shot classification, that is visual recognition of an unseen class by using knowledge transfer from known classes. Our main contribution is COSTA, which exploits co-occurrences of visual concepts in images for knowledge transfer. These inter-dependencies arise naturally between concepts, and are easy to obtain from existing annotations or web-search hit counts. We estimate a classifier for a new label, as a weighted combination of related classes, using the co-occurrences to define the weight. We propose various metrics to leverage these co-occurrences, and a regression model for learning a weight for each related class. We also show that our zero-shot classifiers can serve as priors for few-shot learning. Experiments on three multi-labeled datasets reveal that our proposed zero-shot methods, are approaching and occasionally outperforming fully supervised SVMs. We conclude that co-occurrence statistics suffice for zero-shot classification
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