Pushing the limits of ab-initio-NEGF transport using efficient dissipative Mode-Space algorithms for realistic simulations of low-dimensional semiconductors including their oxide interfaces

We investigate the trade-offs between accuracy and efficiency for several flavors of the dissipative mode-space NEGF algorithm with the self-consistent Born approximation for DFT Hamiltonians. Using these models, we then demonstrate the dissipative self-consistent DFT-NEGF simulations of realistic 2D-material devices including their oxide interfaces with large slab dimensions (up to 1000 atoms) and up to several 100,000 atoms in the full device, pushing the limit of ab-initio transport

Ab-initio Modeling of CBRAM Cells: from Ballistic Transport Properties to Electro-Thermal Effects

We present atomistic simulations of conductive bridging random access memory (CBRAM) cells from first-principles combining density-functional theory and the Non-equilibrium Green's Function formalism. Realistic device structures with an atomic-scale filament connecting two metallic contacts have been constructed. Their transport properties have been studied in the ballistic limit and in the presence of electron-phonon scattering, showing good agreement with experimental data. It has been found that the relocation of few atoms is sufficient to change the resistance of the CBRAM by 6 orders of magnitude, that the electron trajectories strongly depend on the filament morphology, and that self-heating does not affect the device performance at currents below 1 $\mu$A.Comment: 6 figures, conferenc

Hazardous cross-reaction in a thyroid fine needle aspiration.

Thyroid fine-needle aspiration cytology (FNAC) is one of the most performed medical procedures worldwide. <sup>1</sup> It is used as a diagnostic test to separate benign thyroid nodules (colloidal and hyperplastic nodules) from thyroid malignancies, either primary (papillary thyroid carcinoma (PTC), medullary thyroid carcinoma (MTC), poorly differentiated thyroid carcinoma (PDTC), anaplastic thyroid carcinoma (ATC)) or less often metastatic. <sup>2</sup> The negative and positive predictive values (NPV and PPV) of this procedure in The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) are respectively 97% and 98% for the benign and malignant categories. This article is protected by copyright. All rights reserved

Ultralow‐Power Atomic‐Scale Tin Transistor with Gate Potential in Millivolt

After decades of continuous scaling, further advancement of complementary metal-oxide-semiconductor (CMOS) technology across the entire spectrum of computing applications is today limited by power dissipation, which scales with the square of the supply voltage. Here, an atomic-scale tin transistor is demonstrated to perform conductive switching between bistable configurations with on/off potentials ≤2.5 mV in magnitude. In addition to the low operation voltage, the channel length of the transistor is determined experimentally and with density-functional theory to be ≤1 nm because the atoms instead of electrons are information carriers in this device. The conductance at on-states of the bistable configurations varies between 1.2 G$_{0}$ to 197 G$_{0}$ (G$_{0}$ = 2e$^{2}$ h$^{-1}$, e stands for the electron charge and h for Planck\u27s constant). Thus, the device can supply driving current from 1 to ≈375 µA in magnitude for logic circuits with the drain-source dc voltage at decades of millivolts. The switching frequency of the atomic-scale tin transistor has reached 2047 Hz. Furthermore, the on/off potentials in millivolts can reduce the energy consumption in the interconnects of integrated circuits at least by ≈400 times. Therefore, the atomic-scale tin transistor has prospects in digital circuits with ultralow-power dissipation and can contribute to the sustainability of modern society

Mid-gut ACTH-secreting neuroendocrine tumor unmasked with (18)F-dihydroxyphenylalanine-positron emission tomography.

Ectopic ACTH Cushing's syndrome (EAS) is often caused by neuroendocrine tumors (NETs) of lungs, pancreas, thymus, and other less frequent locations. Localizing the source of ACTH can be challenging. A 64-year-old man presented with rapidly progressing fatigue, muscular weakness, and dyspnea. He was in poor condition and showed facial redness, proximal amyotrophy, and bruises. Laboratory disclosed hypokalemia, metabolic alkalosis, and markedly elevated ACTH and cortisol levels. Pituitary was normal on magnetic resonance imaging (MRI), and bilateral inferior petrosal sinus blood sampling with corticotropin-releasing hormone stimulation showed no significant central-to-periphery gradient of ACTH. Head and neck, thoracic and abdominal computerized tomography (CT), MRI, somatostatin receptor scintigraphy (SSRS), and (18)F-deoxyglucose-positron emission tomography (FDG-PET) failed to identify the primary tumor. (18)F-dihydroxyphenylalanine (F-DOPA)-PET/CT unveiled a 20-mm nodule in the jejunum and a metastatic lymph node. Segmental jejunum resection showed two adjacent NETs, measuring 2.0 and 0.5 cm with a peritoneal metastasis. The largest tumor expressed ACTH in 30% of cells. Following surgery, after a transient adrenal insufficiency, ACTH and cortisol levels returned to normal values and remain normal over a follow-up of 26 months. Small mid-gut NETs are difficult to localize on CT or MRI, and require metabolic imaging. Owing to low mitotic activity, NETs are generally poor candidates for FDG-PET, whereas SSRS shows poor sensitivity in EAS due to intrinsically low tumor concentration of type-2 somatostatin receptors (SST2) or to receptor down regulation by excess cortisol. However, F-DOPA-PET, which is related to amine precursor uptake by NETs, has been reported to have high positive predictive value for occult EAS despite low sensitivity, and constitutes a useful alternative to more conventional methods of tumor localization. LEARNING POINTS: Uncontrolled high cortisol levels in EAS can be lethal if untreated.Surgical excision is the keystone of NETs treatment, thus tumor localization is crucial.Most cases of EAS are caused by NETs, which are located mainly in the lungs. However, small gut NETs are elusive to conventional imaging and require metabolic imaging for detection.FDG-PET, based on tumor high metabolic rate, may not detect NETs that have low mitotic activity. SSRS may also fail, due to absent or low concentration of SST2, which may be down regulated by excess cortisol.F-DOPA-PET, based on amine-precursor uptake, can be a useful method to localize the occult source of ACTH in EAS when other methods have failed

Accompagner le monde agricole dans la préservation des messicoles : bilan de trois années d’inventaire et de sensibilisation en Poitou-Charentes

Les messicoles, plantes sauvages des espaces cultivés, sont souvent considérées comme des adventices indésirables par le monde agricole. Ce constat, ainsi que l’intensification des modes de production, ont conduit à une régression généralisée de ces espèces. En Poitou-Charentes, des actions d’inventaire et de conservation des messicoles ont été menées pendant trois ans, accompagnées par une sensibilisation des acteurs du monde agricole à l’importance de leur préservation. Financé par la DREAL Nouvelle-Aquitaine, la région Nouvelle-Aquitaine et une partie en autofinancement, le programme associatif Messicoles en Poitou-Charentes, successeur d’un premier programme similaire réalisé entre 2005 et 2009, se décline en trois volets : inventaire des messicoles à l’échelle de l’ex-région, communication avec outils pédagogiques et actions de conservation en partenariat avec le monde agricole et les gestionnaires d’espaces naturels. Les associations Charente Nature, Deux-Sèvres Nature Environnement, Nature Environnement 17, Vienne Nature et la Ligue pour la protection des oiseaux ont ainsi travaillé conjointement dans la préservation des messicoles en sensibilisant les exploitants et les propriétaires de parcelles hébergeant des espèces à fort enjeu

Site-selective C-C modification of proteins at neutral pH using organocatalyst-mediated cross aldol ligations

The bioconjugation of proteins with small molecules has proved an invaluable strategy for probing and perturbing biological mechanisms. The general use of chemical methods for protein functionalisation can be limited however by the requirement for complicated reaction partners to be present in large excess, and harsh conditions which are incompatible with many protein scaffolds. Herein we describe a site-selective organocatalyst-mediated protein aldol ligation (OPAL) that affords stable carbon-carbon linked bioconjugates at neutral pH. OPAL enables rapid modification of proteins using simple aldehyde probes in minimal excess, and is utilised here in the affinity tagging of proteins in cell lysate. Furthermore we demonstrate that the β-hydroxy aldehyde OPAL product can be functionalised again at neutral pH in a tandem organocatalyst-mediated oxime ligation. This tandem strategy is showcased in the ‘chemical mimicry’ of a previously inaccessible natural dual post-translationally modified protein integral to the pathogenesis of the neglected tropical disease Leishmaniasis

Supramolecular agent–simulant correlations for the luminescence based detection of V-series chemical warfare agents with trivalent lanthanide complexes

Solution spectroscopic investigations into the interactions of eight potential bidentate V-series organophosphorus chemical warfare agent (OP CWA) simulants with [Eu(phen)₂(NO₃)₃]·2H₂O demonstrated that the chemical and structural composition of the secondary binding site within the simulant was of paramount importance. Only simulants containing both phosphoryl/phosphonyl and amine moieties generated analogous spectroscopic behaviours to V-series OP CWAs seen in previous studies. The results demonstrated that the bidentate chelation mechanism was driven by the phosphoryl/phosphonyl moieties and that the presence of the amine moieties induced a significant secondary dynamic luminescence quenching mechanism. The binding modes of the simulants VO and TEEP to trivalent lanthanides (Eu and La) were further investigated using ¹H and ³¹P NMR spectroscopic titrations and kinetic IR experiments. VO, with both the phosphonyl and amine binding sites was found to be the most appropriate simulant for V-series OP CWAs in supramolecular studies with trivalent lanthanide ions and we recommend VO for use in supramolecular studies of this type

Immunotoxins and Anticancer Drug Conjugate Assemblies: The Role of the Linkage between Components

Immunotoxins and antibody-drug conjugates are protein-based drugs combining a target-specific binding domain with a cytotoxic domain. Such compounds are potentially therapeutic against diseases including cancer, and several clinical trials have shown encouraging results. Although the targeted elimination of malignant cells is an elegant concept, there are numerous practical challenges that limit conjugates’ therapeutic use, including inefficient cellular uptake, low cytotoxicity, and off-target effects. During the preparation of immunoconjugates by chemical synthesis, the choice of the hinge component joining the two building blocks is of paramount importance: the conjugate must remain stable in vivo but must afford efficient release of the toxic moiety when the target is reached. Vast efforts have been made, and the present article reviews strategies employed in developing immunoconjugates, focusing on the evolution of chemical linkers