77 research outputs found

    RF Compact Modeling of High-voltage MOSFETs

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    The High-Voltage MOSFET is used in a wide variety of applications covering from power systems up to RF-IC. Compact models that describe the high-frequency behavior of the device are required to predict high-frequency operation and switching capabilities of these elements in HV state-of-the-art systems. In this paper, an RF model is presented and verified against extensive Y-parameter measurements, which were carried out on a long channel Lateral double-Diffusion MOS device. Assessment of the model with measurements confirms the validity of this approach

    Periodontal Ehlers-Danlos Syndrome Is Caused by Mutations in C1R and C1S, which Encode Subcomponents C1r and C1s of Complement

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    Periodontal Ehlers-Danlos syndrome (pEDS) is an autosomal-dominant disorder characterized by early-onset periodontitis leading to premature loss of teeth, joint hypermobility, and mild skin findings. A locus was mapped to an approximately 5.8 Mb region at 12p13.1 but no candidate gene was identified. In an international consortium we recruited 19 independent families comprising 107 individuals with pEDS to identify the locus, characterize the clinical details in those with defined genetic causes, and try to understand the physiological basis of the condition. In 17 of these families, we identified heterozygous missense or in-frame insertion/deletion mutations in C1R (15 families) or C1S (2 families), contiguous genes in the mapped locus that encode subunits C1r and C1s of the first component of the classical complement pathway. These two proteins form a heterotetramer that then combines with six C1q subunits. Pathogenic variants involve the subunit interfaces or inter-domain hinges of C1r and C1s and are associated with intracellular retention and mild endoplasmic reticulum enlargement. Clinical features of affected individuals in these families include rapidly progressing periodontitis with onset in the teens or childhood, a previously unrecognized lack of attached gingiva, pretibial hyperpigmentation, skin and vascular fragility, easy bruising, and variable musculoskeletal symptoms. Our findings open a connection between the inflammatory classical complement pathway and connective tissue homeostasis

    Thermal acclimation increases the stability of a predator-prey interaction in warmer environments.

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    Global warming over the next century is likely to alter the energy demands of consumers and thus the strengths of their interactions with their resources. The subsequent cascading effects on population biomasses could have profound effects on food web stability. One key mechanism by which organisms can cope with a changing environment is phenotypic plasticity, such as acclimation to warmer conditions through reversible changes in their physiology. Here, we measured metabolic rates and functional responses in laboratory experiments for a widespread predator-prey pair of freshwater invertebrates, sampled from across a natural stream temperature gradient in Iceland (4-18℃). This enabled us to parameterize a Rosenzweig-MacArthur population dynamical model to study the effect of thermal acclimation on the persistence of the predator-prey pairs in response to warming. Acclimation to higher temperatures either had neutral effects or reduced the thermal sensitivity of both metabolic and feeding rates for the predator, increasing its energetic efficiency. This resulted in greater stability of population dynamics, as acclimation to higher temperatures increased the biomass of both predator and prey populations with warming. These findings indicate that phenotypic plasticity can act as a buffer against the impacts of environmental warming. As a consequence, predator-prey interactions between ectotherms may be less sensitive to future warming than previously expected, but this requires further investigation across a broader range of interacting species

    Synthesis of New Thieno[2,3-b:5,4-c?]dipyridines

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    Formation of Orthoesters of Oleanolic Acid During Königs-Knorr Glycosidations

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    1,3-Diphenyl-3,4-dihydrobenzo[b][1,6]naphthyridine

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    The title compound, C24H18N2, is the first structural example containing the 3,4-dihydrobenzo[b][1,6]naphthyridine fragment. It was synthesized from 2,4,6,8-tetraphenyl-3,7-diazabicyclo[3.3.1]nonan-9-one and was crystallized from a methanol–ethanol solution over two years as a racemate. The C=N double bond [1.2868 (15) Å] is bent significantly out of the plane of the aromatic bicyclic ring system [N—C—C—C = −157.63 (12)°] and out of the plane of the phenyl ring bonded at the 1-position [N—C—C—C = 41.15 (16)°]

    Reduktion von Dienaddukten der Lävopimarsäsure

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    4-Aminobicyclo[2.2.2]octanone Derivatives with Antiprotozoal Activities

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    3β-Hydroxy-28-norolea-12,17-dien-11-one

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    The title compound, C29H44O2, was formed by treatment of 11-oxooleanolic acid under strong alkaline conditions. The absolute structure of the chiral molecules could not be determined reliably from the diffraction data, but is known from other triterpenes. The asymmetric unit consists of two molecules, 1 and 2. In both molecules, rings A and B show chair conformations. The other rings show mixed forms between envelope and half-chair conformations with atoms in positions 8, 15 and 21 forming the flaps in rings C, D and E, respectively. Rings D and E of molecule 2 are disordered over two orientations, with occupancies of 0.557 (4) and 0.443 (4), which differ in the direction of the flap in ring E. In the crystal, molecules 1, as well as the molecules 2, are linked by O—H...O hydrogen bonds, forming chains parallel to the b axis
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