Optimization and evaluation of variability in the programming window of a flash cell with molecular metal-oxide storage

We report a modeling study of a conceptual nonvolatile memory cell based on inorganic molecular metal-oxide clusters as a storage media embedded in the gate dielectric of a MOSFET. For the purpose of this paper, we developed a multiscale simulation framework that enables the evaluation of variability in the programming window of a flash cell with sub-20-nm gate length. Furthermore, we studied the threshold voltage variability due to random dopant fluctuations and fluctuations in the distribution of the molecular clusters in the cell. The simulation framework and the general conclusions of our work are transferrable to flash cells based on alternative molecules used for a storage media

Comparison between bulk and FDSOI POM flash cell: a multiscale simulation study

In this brief, we present a multiscale simulation study of a fully depleted silicon-on-insulator (FDSOI) nonvolatile memory cell based on polyoxometalates (POMs) inorganic molecular clusters used as a storage media embedded in the gate dielectric of flash cells. In particular, we focus our discussion on the threshold voltage variability introduced by random discrete dopants (random dopant fluctuation) and by fluctuations in the distribution of the POM molecules in the storage media (POM fluctuation). To highlight the advantages of the FDSOI POM flash cell, we provide a comparison with an equivalent cell based on conventional (BULK) transistors. The presented simulation framework and methodology is transferrable to flash cells based on alternative molecules used as a storage media

A 16 x 16 CMOS amperometric microelectrode array for simultaneous electrochemical measurements

There is a requirement for an electrochemical sensor technology capable of making multivariate measurements in environmental, healthcare, and manufacturing applications. Here, we present a new device that is highly parallelized with an excellent bandwidth. For the first time, electrochemical cross-talk for a chip-based sensor is defined and characterized. The new CMOS electrochemical sensor chip is capable of simultaneously taking multiple, independent electroanalytical measurements. The chip is structured as an electrochemical cell microarray, comprised of a microelectrode array connected to embedded self-contained potentiostats. Speed and sensitivity are essential in dynamic variable electrochemical systems. Owing to the parallel function of the system, rapid data collection is possible while maintaining an appropriately low-scan rate. By performing multiple, simultaneous cyclic voltammetry scans in each of the electrochemical cells on the chip surface, we are able to show (with a cell-to-cell pitch of 456 μm) that the signal cross-talk is only 12% between nearest neighbors in a ferrocene rich solution. The system opens up the possibility to use multiple independently controlled electrochemical sensors on a single chip for applications in DNA sensing, medical diagnostics, environmental sensing, the food industry, neuronal sensing, and drug discovery

Composite SUVR: a new method for boosting Alzheimer's disease monitoring and diagnostic performance, applied to tau PET

Background: Abnormal brain tau protein accumulation is strongly linked to multiple neurodegenerative disorders. Currently, brain tau pathology is quantified in vivo using tau PET by calculating the Standardized Uptake Value Ratio (SUVR) of target and reference regions of interest (ROIs). Recent work (Schwarz et al., 2021) in Alzheimer’s Disease (AD) explored various target and reference ROIs to report performance of SUVR as a biomarker for diagnosis, disease monitoring, and clinical trial efficacy/eligibility (sample size estimate, SSE). Here we introduce a new method and biomarker: Composite SUVR (CUVR). / Methods: We analyzed longitudinal SUV data from ADNI in the available 103 participants having three or more tau PET scans ([18F]AV-1451): 58 cognitively normal (CN); 21 mild cognitive impairment; 24 probable AD. In the spirit of SUVR and statistical ROIs (Chen, et al., NeuroImage 2010), we calculate CUVR as the SUV ratio of two composite regions. Our novel method is that the composite regions are determined by a genetic algorithm that searches the possible 3^96 combinations of regions from FreeSurfer’s default atlas. We compare performance of SUVR with CUVR. Performance metrics follow Schwarz et al.: a linear mixed-effects model quantifies longitudinal group separation by tau accumulation rate (t statistic between fixed effects for CN and AD) and longitudinal precision (model residuals’ standard deviation). CUVR and SUVR values were log-transformed before model fitting. We calculated SSE for a hypothetical clinical trial designed for 80% power to reduce tau PET accumulation by 20% (vs. placebo) in non-CN individuals. / Results: Our method identified a CUVR biomarker involving 60 regions. Figure-1 shows the vast performance improvement of CUVR versus the best-performing SUVR (inferior-temporal target; eroded subcortical white matter reference). Group separation improved by 2.9x (t = 9.57 vs 3.32); longitudinal precision by 6.5x (residual std = 0.331% vs 2.14%); and CUVR required a smaller sample size by 3.9x (83 vs 318). / Conclusions: Our simple data-driven approach discovered a new tau PET biomarker called CUVR. Experimental results show state-of-the-art longitudinal group separation, longitudinal precision, and clinical trial enrichment. The remarkable performance improvements provide compelling evidence for using CUVR for both eligibility and efficacy in Alzheimer’s disease clinical trials, particularly of anti-tau therapies

Dynamic structure factor of Luttinger liquids with quadratic energy dispersion and long-range interactions

We calculate the dynamic structure factor S (omega, q) of spinless fermions in one dimension with quadratic energy dispersion k^2/2m and long range density-density interaction whose Fourier transform f_q is dominated by small momentum-transfers q << q_0 << k_F. Here q_0 is a momentum-transfer cutoff and k_F is the Fermi momentum. Using functional bosonization and the known properties of symmetrized closed fermion loops, we obtain an expansion of the inverse irreducible polarization to second order in the small parameter q_0 / k_F. In contrast to perturbation theory based on conventional bosonization, our functional bosonization approach is not plagued by mass-shell singularities. For interactions which can be expanded as f_q = f_0 + f_0^{2} q^2/2 + O (q^4) with finite f_0^{2} we show that the momentum scale q_c = 1/ | m f_0^{2} | separates two regimes characterized by a different q-dependence of the width gamma_q of the collective zero sound mode and other features of S (omega, q). For q_c << q << k_F we find that the line-shape in this regime is non-Lorentzian with an overall width gamma_q of order q^3/(m q_c) and a threshold singularity at the lower edge.Comment: 33 Revtex pages, 17 figure

Functional renormalization group in the broken symmetry phase: momentum dependence and two-parameter scaling of the self-energy

We include spontaneous symmetry breaking into the functional renormalization group (RG) equations for the irreducible vertices of Ginzburg-Landau theories by augmenting these equations by a flow equation for the order parameter, which is determined from the requirement that at each RG step the vertex with one external leg vanishes identically. Using this strategy, we propose a simple truncation of the coupled RG flow equations for the vertices in the broken symmetry phase of the Ising universality class in D dimensions. Our truncation yields the full momentum dependence of the self-energy Sigma (k) and interpolates between lowest order perturbation theory at large momenta k and the critical scaling regime for small k. Close to the critical point, our method yields the self-energy in the scaling form Sigma (k) = k_c^2 sigma^{-} (k | xi, k / k_c), where xi is the order parameter correlation length, k_c is the Ginzburg scale, and sigma^{-} (x, y) is a dimensionless two-parameter scaling function for the broken symmetry phase which we explicitly calculate within our truncation.Comment: 9 pages, 4 figures, puplished versio

Radiative Transfer in Obliquely Illuminated Accretion Disks

The illumination of an accretion disk around a black hole or neutron star by the central compact object or the disk itself often determines its spectrum, stability, and dynamics. The transport of radiation within the disk is in general a multi-dimensional, non-axisymmetric problem, which is challenging to solve. Here, I present a method of decomposing the radiative transfer equation that describes absorption, emission, and Compton scattering in an obliquely illuminated disk into a set of four one-dimensional transfer equations. I show that the exact calculation of the ionization balance and radiation heating of the accretion disk requires the solution of only one of the one-dimensional equations, which can be solved using existing numerical methods. I present a variant of the Feautrier method for solving the full set of equations, which accounts for the fact that the scattering kernels in the individual transfer equations are not forward-backward symmetric. I then apply this method in calculating the albedo of a cold, geometrically thin accretion disk.Comment: 16 pages, 3 figures; to appear in The Astrophysical Journa

Aktualisierung der Empfehlungen zur standardisierten Diagnostik und Klassifikation von Kaumuskel- und Kiefergelenkschmerzen

Zusammenfassung: Hintergrund: Im Jahre 2000 veröffentlichte der Interdisziplinäre Arbeitskreis für Mund- und Gesichtsschmerzen in der Deutschen Gesellschaft zum Studium des Schmerzes Empfehlungen zur Diagnostik und Klassifikation von Patienten mit Schmerzen im Bereich der Kaumuskulatur und/oder Kiefergelenke. Ziele der vorliegenden Publikation sind eine Bestandsaufnahme und Aktualisierung der damals gemachten Vorschläge. Ergebnisse: Sichtung und Bewertung der nach Veröffentlichung der Empfehlungen erschienenen Fachliteratur (bis Dezember 2005) zeigen, dass sich das zweiachsige Stufenkonzept zur Erfassung somatischer und psychosozialer Parameter orofazialer Schmerzen bewährt hat. Einzelne Aspekte der Empfehlungen wurden in Form wissenschaftlicher Belege weiter konkretisiert. Schlussfolgerungen: Die vorgeschlagenen Empfehlungen spiegeln die aktuellen Entwicklungen in der Schmerzmedizin wider. Insbesondere in der Zahnärzteschaft sollten sie daher eine noch breitere Verankerung finden als bishe