| 1. |
- Abdalla, Munir A, et al.
(author)
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A CMOS APS for dental X-ray imaging using scintillating sensors
- 2001
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In: Nuclear Instruments and Methods in Physics Research Section A. - 0168-9002 .- 1872-9576. ; 460:1, s. 197-203
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Journal article (peer-reviewed)abstract
- In this paper we present an integrating CMOS Active Pixel Sensor (APS) circuit to be used with scintillator type X-ray sensors for intra oral dental X-ray imaging systems. Different pixel architectures were constructed to explore their performance characteristics and to study the feasibility of the development of such systems using the CMOS technology. A prototype 64 x 80 pixel array has been implemented in a CMOS 0.8 mum double poly n-well process with a pixel pitch of 50 mum. A spectral sensitivity measurement for the different pixels topologies, as well as measured X-ray direct absorption in the different APSs are presented. A measurement of the output signal showed a good linearity over a wide dynamic range. This chip showed that the very low sensitivity of the CMOS APSs to direct X-ray exposure adds a great advantage to the various CMOS advantages over CCD-based imaging systems,
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| 2. |
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| 3. |
- Abdalla, Munir A, et al.
(author)
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An integrating CMOS APS for X-ray imaging with an in-pixel preamplifier
- 2001
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In: Nuclear Instruments and Methods in Physics Research Section A. - 0168-9002 .- 1872-9576. ; 466:1, s. 232-236
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Journal article (peer-reviewed)abstract
- We present in this paper an integrating CMOS Active Pixel Sensor (APS) circuit coated with scintillator type sensors for intra-oral dental X-ray imaging systems. The photosensing element in the pixel is formed by the p-diffusion on the n-well diode. The advantage of this photosensor is its very low direct absorption of X-rays compared to the other available photosensing elements in the CMOS pixel. The pixel features an integrating capacitor in the feedback loop of a preamplifier of a finite gain in order to increase the optical sensitivity. To verify the effectiveness of this in-pixel preamplification, a prototype 32 x 80 element CMOS active pixel array was implemented in a 0.8 mum CMOS double poly, n-well process with a pixel pitch of 50 mum. Measured results confirmed the improved optical sensitivity performance of the APS. Various measurements on device performance are presented.
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| 6. |
- Klionsky, Daniel J., et al.
(author)
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Guidelines for the use and interpretation of assays for monitoring autophagy
- 2012
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In: Autophagy. - : Informa UK Limited. - 1554-8635 .- 1554-8627. ; 8:4, s. 445-544
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Research review (peer-reviewed)abstract
- In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
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| 7. |
- Lundgren, Jan, et al.
(author)
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A power-line noise coupling estimation methodology for architectural exploration of mixed-signal systems
- 2003
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In: Proceedings of the Southwest Symposium on Mixed-Signa Design. - : IEEE Press. - 0780377788 ; , s. 133-137
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Conference paper (peer-reviewed)abstract
- This paper presents methods for early estimation of digital to analog noise coupling over the power distribution network in mixed-signal systems. The methods allow both behavioral verification of mixed-signal architectures and their sensitivity to noise coupling of the power distribution network. The behavioral level noise coupling simulation models are implemented as extensions to the SystemC system design language. To illustrate the effectiveness of the proposed methods, we have estimated the power distribution network noise for a photon-counting X-ray pixel array and compared this with SPICE simulations.
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| 8. |
- Lundgren, Jan, 1977-, et al.
(author)
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Behavioral Simulation of Power Line Noise Coupling in Mixed-Signal Systems using SystemC
- 2003
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In: ISVLSI 2003: IEEE COMPUTER SOCIETY ANNUAL SYMPOSIUM ON VLSI, PROCEEDINGS - NEW TRENDS AND TECHNOLOGIES FOR VLSI SYSTEMS DESIGN. - : IEEE. - 0769519040 ; , s. 275-277
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Conference paper (peer-reviewed)abstract
- This paper presents methods for early quantification of digital to analog noise coupling at behavioral level. The methods enable designers to both verify the behavior of their mixed-signal architecture and its sensitivity to noise coupling. The high-level noise coupling simulation models are implemented as extensions to SystemC.
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| 9. |
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| 10. |
- Marchal, J, et al.
(author)
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Active pixel detector for ion beam profiling
- 2002
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In: Nuclear Instruments and Methods in Physics Research Section A. - 0168-9002 .- 1872-9576. ; 487:1-2, s. 224-231
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Journal article (peer-reviewed)
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| 11. |
- Oelmann, Bengt, et al.
(author)
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Robust window discriminator for photon-counting pixel detectors
- 2002
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In: IEE Proceedings - Optoelectronics. - : Institution of Engineering and Technology (IET). - 1350-2433 .- 1359-7078. ; 149:2, s. 65-69
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Journal article (peer-reviewed)abstract
- The paper proposes a robust and area-efficient way of designing window discriminators for photon-counting pixel detectors. For that, an all-digital window discriminator is proposed. It is event-driven and does not rely on any external or internal timing references, which makes it possible to use it over a wide range of specifications. In addition, it provides an overall area efficient implementation of the digital electronics in photon-counting pixel detectors. The transistor-level implementation of the circuit is presented with its circuit area and timing performance.
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| 12. |
- O'Nils, Mattias, et al.
(author)
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Low Digital Interference Counter for Photon Counting Pixel Detectors
- 2002
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In: Nuclear Instruments and Methods in Physics Research, Section A. - 0168-9002. ; 487:3, s. 323-330
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Journal article (peer-reviewed)abstract
- Single photon-counting pixel sensors are widely used in radiation imaging because of their energy resolving capability and high dynamic range. However, the close integration of the analog and digital circuits in the small pixel area puts critical constraints on the mixed mode circuit design. This includes the design considerations regarding the noise injection from the digital circuits into the analog part due to the digital switching. In addition, the large number of components requires a pixel circuit with low power consumption. In this paper, we address these two design constraints. An event counter architecture that decreases the digital switching and power consumption in a pixel is presented. The counter has the same dynamic range for capturing events and hardware cost as the conventionally used counters. We present design rules for adopting the counter architecture to a certain application. These rules enable the trade-off between readout accuracy from the pixel vs. the current in the digital parts of the pixel. Simulation of a case study circuit shows a reduction of digital activity by a factor seven, and a significant reduction of power consumption.
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| 13. |
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