A 12b 50MS/s 2.1mW SAR ADC with redundancy and digital background calibration

A 12-bit 50MS/s SAR ADC implemented in 65nm CMOS technology is presented. The design employs redundancy to relax the DAC settling requirement and to provide sufficient room for errors such that the static nonlinearity caused by capacitor mismatches can be digitally removed. The redundancy is incorporated into the design using a tri-level switching scheme and our modified split-capacitor array to achieve the highest switching efficiency while still preserving the symmetry in error tolerance. A new code-density based digital background calibration algorithm that requires no special calibration signals or additional analog hardware is also developed. The calibration is performed by using the input signal as stimulus and the effectiveness is verified both in simulation and through measured data. The prototype achieves a 67.4dB SNDR at 50MS/s, while dissipating 2.1mW from a 1.2V supply, leading to FoM of 21.9fJ/conv.-step at Nyquist frequency.MIT Masdar Progra

Investigation of CTA 1 with Suzaku Observation

We report on an 105 ks Suzaku observation of the supernova remnant CTA 1 (G119.5+10.2). The Suzaku soft X-ray observation was carried out with both timing mode and imaging mode. A ~ 10' extended feature, which is interpreted as a bow-shock component of the pulsar wind nebula (PWN), is revealed in this deep observation for the first time. The nebular spectrum can be modelled by a power-law with a photon index of ~ 1.8 which suggests a slow synchrotron cooling scenario. The photon index is approximately constant across this extended feature. We compare and discuss our observations of this complex nebula with previous X-ray investigations. We do not obtain any significant pulsation from the central pulsar in the soft (0.2-12 keV) and hard (10-60 keV) X-ray data. The non-detection is mainly due to the loss of the precise imaging ability to accurately determine the source contribution. The spectra of XIS and HXD can be directly connected without a significant spectral break according to our analysis. Future observations of NuSTAR and Astro-H would be able to resolve the contamination and provide an accurate hard X-ray measurement of CTA 1.Comment: 9 pages, 7 figures, accepted by MNRA

Test structure, circuits and extraction methods to determine the radius of infuence of STI and polysilicon pattern density

Advanced CMOS processes need new methodologies to extract, characterize and model process variations and their sources. Most prior studies have focused on understanding the effect of local layout features on transistor performance; limited work has been done to characterize medium-range (≈ 10μm to 2mm) pattern density effects. We propose a new methodology to extract the radius of influence, or the range of neighboring layout that should be taken into account in determining transistor characteristics, for shallow trench isolation (STI) and polysilicon pattern density. A test chip, with 130k devices under test (DUTs) and step-like pattern density layout changes, is designed in 65nm bulk CMOS technology as a case study. The extraction result of the measured data suggests that the local layout geometry, within the DUT cell size of 6μm × 8μm, is the dominant contributor to systematic device variation. Across-die medium-range layout pattern densities are found to have a statistically significant and detectable effect, but this effect is small and contributes only 2-5% of the total variation in this technology

Genomic regions associated with chocolate spot (Botrytis fabae Sard.) resistance in faba bean (Vicia faba L.)

Chocolate spot (CS), caused by Botrytis fabae Sard., is an important threat to global faba bean production. Growing resistant faba bean cultivars is, therefore, paramount to preventing yield loss. To date, there have been no reported quantitative trait loci (QTL) associated with CS resistance in faba bean. The objective of this study was to identify genomic regions associated with CS resistance using a recombinant inbred line (RIL) population derived from resistant accession ILB 938. A total of 165 RILs from the cross Melodie/2 x ILB 938/2 were genotyped and evaluated for CS reactions under replicated controlled climate conditions. The RIL population showed significant variation in response to CS resistance. QTL analysis identified five loci contributing to CS resistance on faba bean chromosomes 1 and 6, accounting for 28.4% and 12.5%, respectively, of the total phenotypic variance. The results of this study not only provide insight into disease-resistance QTL, but also can be used as potential targets for marker-assisted breeding in faba bean genetic improvement for CS resistance.Peer reviewe

Reduction of freezing of gait in Parkinson's disease by repetitive robot-assisted treadmill training: a pilot study

<p>Abstract</p> <p>Background</p> <p>Parkinson's disease is a chronic, neurodegenerative disease characterized by gait abnormalities. Freezing of gait (FOG), an episodic inability to generate effective stepping, is reported as one of the most disabling and distressing parkinsonian symptoms. While there are no specific therapies to treat FOG, some external physical cues may alleviate these types of motor disruptions. The purpose of this study was to examine the potential effect of continuous physical cueing using robot-assisted sensorimotor gait training on reducing FOG episodes and improving gait.</p> <p>Methods</p> <p>Four individuals with Parkinson's disease and FOG symptoms received ten 30-minute sessions of robot-assisted gait training (Lokomat) to facilitate repetitive, rhythmic, and alternating bilateral lower extremity movements. Outcomes included the FOG-Questionnaire, a clinician-rated video FOG score, spatiotemporal measures of gait, and the Parkinson's Disease Questionnaire-39 quality of life measure.</p> <p>Results</p> <p>All participants showed a reduction in FOG both by self-report and clinician-rated scoring upon completion of training. Improvements were also observed in gait velocity, stride length, rhythmicity, and coordination.</p> <p>Conclusions</p> <p>This pilot study suggests that robot-assisted gait training may be a feasible and effective method of reducing FOG and improving gait. Videotaped scoring of FOG has the potential advantage of providing additional data to complement FOG self-report.</p

Prospective Electrocardiogram-Gated Delayed Enhanced Multidetector Computed Tomography Accurately Quantifies Infarct Size and Reduces Radiation Exposure

ObjectivesThis study sought to determine whether low-dose, prospective electrocardiogram (ECG)-gated delayed contrast-enhanced multidetector computed tomography (DCE-MDCT) can accurately delineate the extent of myocardial infarction (MI) compared with retrospective ECG-gated DCE-MDCT.BackgroundFor defining the location and extent of MI, DCE-MDCT compares well with delayed enhanced cardiac magnetic resonance. However, the addition of a delayed scan requires additional radiation exposure to patients. MDCT protocols using prospective ECG gating can substantially reduce effective radiation dose exposure, but these protocols have not yet been applied to infarct imaging.MethodsTen porcine models of acute MI were imaged 10 days after MI using prospective and retrospective ECG-gated DCE-MDCT (64-slice) 10 min after a 90-ml contrast bolus. The MDCT images were analyzed using a semiautomated computed tomography density (CTD) threshold technique. Infarct size, signal-to-noise (SNR) ratios, contrast-to-noise (CNR) ratios, and image quality metrics were compared between the 2 ECG-gating techniques.ResultsInfarct volume measurements obtained by both methods were strongly correlated (R = 0.93, p < 0.001) and in good agreement (mean difference: −0.46 ml ± 4.00%). Compared with retrospective ECG gating, estimated radiation dosages were markedly reduced with prospective ECG gating (930.1 ± 62.2 mGy×cm vs. 42.4 ± 2.3 mGy×cm, p < 0.001). The SNR and CNR of infarcted myocardium were somewhat lower for prospective gated images (22.0 ± 11.0 vs. 16.3 ± 7.8 and 8.8 ± 5.3 vs. 7.0 ± 3.9, respectively; p < 0.001). However, all examinations using prospective gating protocol achieved sufficient diagnostic image quality for the assessment of MI.ConclusionsProspective ECG-gated DCE-MDCT accurately assesses infarct size compared with retrospective ECG-gated DCE-MDCT imaging. Although infarct SNR and CNR were significantly higher for the retrospective gated protocol, prospective ECG-gated DCE-MDCT provides high-resolution imaging of MI, while substantially lowering the radiation dose