| 1. |
- Larsson, D. G. Joakim, 1969, et al.
(författare)
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Critical knowledge gaps and research needs related to the environmental dimensions of antibiotic resistance
- 2018
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Ingår i: Environment International. - : Elsevier BV. - 0160-4120 .- 1873-6750. ; 117, s. 132-138
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Forskningsöversikt (refereegranskat)abstract
- There is growing understanding that the environment plays an important role both in the transmission of antibiotic resistant pathogens and in their evolution. Accordingly, researchers and stakeholders world-wide seek to further explore the mechanisms and drivers involved, quantify risks and identify suitable interventions. There is a clear value in establishing research needs and coordinating efforts within and across nations in order to best tackle this global challenge. At an international workshop in late September 2017, scientists from 14 countries with expertise on the environmental dimensions of antibiotic resistance gathered to define critical knowledge gaps. Four key areas were identified where research is urgently needed: 1) the relative contributions of different sources of antibiotics and antibiotic resistant bacteria into the environment; 2) the role of the environment, and particularly anthropogenic inputs, in the evolution of resistance; 3) the overall human and animal health impacts caused by exposure to environmental resistant bacteria; and 4) the efficacy and feasibility of different technological, social, economic and behavioral interventions to mitigate environmental antibiotic resistance.(1)
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| 2. |
- Vishnu, N., et al.
(författare)
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Mitochondrial clearance of calcium facilitated by MICU2 controls insulin secretion
- 2021
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Ingår i: Molecular Metabolism. - : Elsevier. - 2212-8778. ; 51
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Transport of Ca2+ into pancreatic 13 cell mitochondria facilitates nutrient-mediated insulin secretion. However, the underlying mechanism is unclear. Recent establishment of the molecular identity of the mitochondrial Ca2+ uniporter (MCU) and associated proteins allows modification of mitochondrial Ca2+ transport in intact cells. We examined the consequences of deficiency of the accessory protein MICU2 in rat and human insulin-secreting cells and mouse islets. Methods: siRNA silencing of Micu2 in the INS-1 832/13 and EndoC-13H1 cell lines was performed; Micu2-/- mice were also studied. Insulin secretion and mechanistic analyses utilizing live confocal imaging to assess mitochondrial function and intracellular Ca2+ dynamics were performed. Results: Silencing of Micu2 abrogated GSIS in the INS-1 832/13 and EndoC-13H1 cells. The Micu2-/- mice also displayed attenuated GSIS. Mitochondrial Ca2+ uptake declined in MICU2-deficient INS-1 832/13 and EndoC-13H1 cells in response to high glucose and high K+. MICU2 silencing in INS-1 832/13 cells, presumably through its effects on mitochondrial Ca2+ uptake, perturbed mitochondrial function illustrated by absent mitochondrial membrane hyperpolarization and lowering of the ATP/ADP ratio in response to elevated glucose. Despite the loss of mitochondrial Ca2+ uptake, cytosolic Ca2+ was lower in siMICU2-treated INS-1 832/13 cells in response to high K+. It was hypothesized that Ca2+ accumulated in the submembrane compartment in MICU2-deficient cells, resulting in desensitization of voltage-dependent Ca2+ channels, lowering total cytosolic Ca2+. Upon high K+ stimulation, MICU2-silenced cells showed higher and prolonged increases in submembrane Ca2+ levels. Conclusions: MICU2 plays a critical role in 13 cell mitochondrial Ca2+ uptake. 13 cell mitochondria sequestered Ca2+ from the submembrane compartment, preventing desensitization of voltage-dependent Ca2+ channels and facilitating GSIS.
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| 3. |
- Cherkaoui, K., et al.
(författare)
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High-k/InGaAs interface defects at cryogenic temperature
- 2023
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Ingår i: Solid-State Electronics. - 0038-1101. ; 207
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Tidskriftsartikel (refereegranskat)abstract
- Oxide defects in the high-k/InGaAs MOS system are investigated. The behaviour of these traps is explored from room temperature down to 10 K. This study reveals that the exchange of free carriers between oxide states and either the conduction or the valence band is strongly temperature dependant. The capture and emission of electrons is strongly suppressed at 10 K as demonstrated by the collapse of the capacitance frequency dispersion in accumulation for n-InGaAs MOS devices, though hysteresis in the C-V sweeps is still present at 10 K. Phonon assisted tunnelling processes are considered in the simulation of electrical characteristics. The simulated data match very well the experimental characteristics and provide energy and spatial mapping of oxide defects. The multi phonon theory also help explain the impedance data temperature dependence. This study also reveals an asymmetry in the free carrier trapping between n and p type devices, where hole trapping is more significant at 10 K.
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| 4. |
- Floor, P. A., et al.
(författare)
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Power constrained channel optimized vector quantizers used for bandwidth expansion
- 2007
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Ingår i: Proceedings of 4th IEEE Internatilonal Symposium on Wireless Communication Systems 2007, ISWCS. - New York : IEEE. - 9781424409792 - 1424409799 ; , s. 667-671
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Konferensbidrag (refereegranskat)abstract
- This paper deals with algorithms for determining well performing bandwidth expanding joint source-channel coding (JSCC) systems. The JSCC systems are realized as direct source-channel mappings. The algorithms presented are "Power Constrained Channel Optimized Vector Quantizers" (PCCOVQ). The PCCOVQ algorithm is a modified generalized Lloyd algorithm. Theory on PCCOVQ is presented, with the emphasis on bandwidth expansion. Examples and results concerning bandwidth expansion by a factor of 2 and 3 are given.
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| 5. |
- Floor, P. A., et al.
(författare)
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Transmitting multiple correlated gaussian sources over a Gaussian MAC using delay-free mappings
- 2011
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Ingår i: ISABEL '11 Proceedings of the 4th International Symposium on Applied Sciences in Biomedical and Communication Technologies. - New York, NY, USA : ACM. - 9781450309134
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Konferensbidrag (refereegranskat)abstract
- In this paper, we study the problem of communicating multiple correlated Gaussian memoryless sources over a Gaussian Multiple Access Channel (GMAC). We focus on distributed delay-free, low complexity, joint source-channel coding (JSCC) solutions to the problem. Theoretical performance bounds are derived and linear and nonlinear JSCC schemes are evaluated. The main contribution is a nonlinear hybrid discrete-analog mapping based on distributed quantization and a linear continuous mapping named Distributed Quantizer Linear Coder (DQLC). The proposed scheme shows promising performance which improve with increasing correlation and is robust against variations in noise level.
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| 6. |
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| 7. |
- Passlack, M., et al.
(författare)
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Core-shell tfet developments and tfet limitations
- 2019
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Ingår i: 2019 International Symposium on VLSI Technology, Systems and Application, VLSI-TSA 2019. - 9781728109428
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Konferensbidrag (refereegranskat)abstract
- Tunneling field-effect transistors (TFET) based on a vertical gate-All-Around (VGAA) nanowire (NW) architecture with a core-shell (CS) structure have been explored for future CMOS applications. Performance predictions based on a tight-binding mode-space NEGF technique include a drive current \mathrm{I}-{\mathrm{o}\mathrm{n}} of 6.7\ \mu \mathrm{A} (NW diameter \mathrm{d}= 10.2\ \mathrm{nm}) at \mathrm{V}-{\mathrm{dd}}=0.3\ \mathrm{V} under low power (LP) conditions (\mathrm{I}-{\mathrm{off}}=1 \mathrm{pA}) for an InAs/GaSb CS TFET. This compares to Si nMOSFET \mathrm{I}-{\mathrm{on}} =2.3\ \mu \mathrm{A} at \mathrm{V}-{\mathrm{dd}}=0.55\ \mathrm{V}(\mathrm{d}=6\ \mathrm{nm}). On the experimental side, scaling of vertical CS NWs resulted in smallest dimensions of \mathrm{d}-{\mathrm{c}}= 17 nm (GaSb core) and \mathrm{t}-{\mathrm{sh}}=3 nm (InAs shell) for a total diameter of 23 nm. VGAA CS nFETs demonstrated drive current of up to 40\ \mu \mathrm{A} (\mathrm{V}-{\mathrm{d}}=0.3\ \mathrm{V}) and subthreshold swing \mathrm{SS}=40\mathrm{mV}/\mathrm{dec}(\mathrm{V}-{\mathrm{d}}=10\mathrm{mV}) for NW diameters between 35-50 nm. Although key TFET properties such as current drive and subthermal SS have been demonstrated using a VGAA CS architecture for the first time, experimental results still lag predictions. An intrinsic relationship between band-To band-Tunneling (BTBT) and \mathrm{D}-{\mathrm{it}} related trap assisted tunneling (TAT) was found which imposes challenging \mathrm{D}-{\mathrm{it}} requirements, in particular for LP \mathrm{I}-{\mathrm{off}} specifications. Complexity of fabrication and a material system foreign to CMOS manufacturing further impact prospects of TFET technology.
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| 8. |
- Rosca, T., et al.
(författare)
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An Experimental Study of Heterostructure Tunnel FET Nanowire Arrays : Digital and Analog Figures of Merit from 300K to 10K
- 2019
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Ingår i: 2018 IEEE International Electron Devices Meeting, IEDM 2018. - 9781728119878 ; 2018, s. 1-13
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Konferensbidrag (refereegranskat)abstract
- In this work, we experimentally report the figures of merit of state-of-the-art heterostructure Tunnel Field-Effect-Transistor (TFET) arrays from room (300K) down to cryogenic temperature (10K) at supply voltages below 400mV. We demonstrate here, for the first time, that InAs/InGaAsSb/GaSb Nanowire (NW) TFETs are robust enough to maintain excellent figures of merit over a large temperature range even in devices with a large number arrayed nanowires (here, from 4 to 184 nanowires per device), accounting for technological variability. The investigated Tunnel FETs have temperature-independent min and average subthreshold swings of 45mV/dec/67mV/dec in large NW arrays, versus ∼36/45mV/dec in smaller arrays, once the trap-assisted tunneling is removed (from 150K down to 10K). In all NW arrays we observe improvement of the on-current and of maximum transconductance, gmax, at cryogenic temperatures, with very little dependence of temperature, from 150K to 10K. The paper reports that in the range 150K to 10K only band-to-band-tunneling dominates the analog figures of merit of Tunnel FETs; we measured transconductance efficiencincies higher than 60V -1 for small arrays (breaking the limit of CMOS at RT) and close to 42V -1 for large arrays, for supply volrages smaller than 100mV, offering the possibility to design future energy efficient readouts and analog-to-digital converters. In contrast with cryogenic MOSFETs, Tunnel FETs show almost no hysteresis (<24mV), steep transfer characteristics, are free of kinks in output characteristics, with a unique stability of the swing drift with T, and negligible threshold voltage drift in all arrays configurations.
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| 9. |
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| 10. |
- Vasen, T., et al.
(författare)
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InAs nanowire GAA n-MOSFETs with 12-15 nm diameter
- 2016
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Ingår i: 2016 IEEE Symposium on VLSI Technology, VLSI Technology 2016. - 9781509006373 ; 2016-September
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Konferensbidrag (refereegranskat)abstract
- InAs nanowires (NW) grown by MOCVD with diameter d as small as 10 nm and gate-All-Around (GAA) MOSFETs with d = 12-15 nm are demonstrated. Ion = 314 μA/μm, and Ssat =68 mV/dec was achieved at Vdd = 0.5 V (Ioff = 0.1 μA/μm). Highest gm measured is 2693 μS/μm. Device performance is enabled by small diameter and optimized high-k/InAs gate stack process. Device performance tradeoffs between gm, Ron, and Imin are discussed.
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