1,824 research outputs found
Intrinsic Metastabilities in the Charge Configuration of a Double Quantum Dot
We report a thermally activated metastability in a GaAs double quantum dot
exhibiting real-time charge switching in diamond shaped regions of the charge
stability diagram. Accidental charge traps and sensor back action are excluded
as the origin of the switching. We present an extension of the canonical double
dot theory based on an intrinsic, thermal electron exchange process through the
reservoirs, giving excellent agreement with the experiment. The electron spin
is randomized by the exchange process, thus facilitating fast, gate-controlled
spin initialization. At the same time, this process sets an intrinsic upper
limit to the spin relaxation time.Comment: 4 pages, 5 figures (color
Photosystem I lacking the PSI-G subunit has a higher affinity for plastocyanin and is sensitive to photodamage
GaAs Quantum Dot Thermometry Using Direct Transport and Charge Sensing
We present measurements of the electron temperature using gate defined
quantum dots formed in a GaAs 2D electron gas in both direct transport and
charge sensing mode. Decent agreement with the refrigerator temperature was
observed over a broad range of temperatures down to 10 mK. Upon cooling nuclear
demagnetization stages integrated into the sample wires below 1 mK, the device
electron temperature saturates, remaining close to 10 mK. The extreme
sensitivity of the thermometer to its environment as well as electronic noise
complicates temperature measurements but could potentially provide further
insight into the device characteristics. We discuss thermal coupling
mechanisms, address possible reasons for the temperature saturation and
delineate the prospects of further reducing the device electron temperature.Comment: 8 pages, 3 (color) figure
Transcriptional alterations under continuous or pulsatile dopaminergic treatment in dyskinetic rats
Continuous dopaminergic treatment is considered to prevent or delay the occurrence of dyskinesia in patients with Parkinson's disease (PD). Rotigotine is a non-ergolinic D3>D2>D1 dopamine-receptor agonist for the treatment of PD using a transdermal delivery system providing stable plasma levels. We aimed to investigate the differential influence on gene expression of pulsatile l-DOPA or rotigotine versus a continuous rotigotine treatment. The gene expression profile within the nigro-striatal system of unilateral 6-hydroxydopamine-lesioned rats was assessed in order to differentiate potential changes in gene expression following the various treatment using Affymetrix microarrays and quantitative RT-PCR. The expression of 15 genes in the substantia nigra and of 11 genes in the striatum was altered under pulsatile treatments inducing dyskinetic motor response, but was unchanged under continuous rotigotine treatment that did not cause dyskinetic motor response. The route of administration of a dopaminergic drug is important for the induction or prevention of motor abnormalities and adaptive gene expressions. The decline of neurotrophin-3 expression under pulsatile administration was considered of particular importanc
The Trofobiose Theory and organic agriculture: the active mobilization of nutrients and the use of rock powder as a tool for sustainability
Saccharomyces cerevisiae: a versatile eukaryotic system in virology
The yeast Saccharomyces cerevisiae is a well-established model system for understanding fundamental cellular processes relevant to higher eukaryotic organisms. Less known is its value for virus research, an area in which Saccharomyces cerevisiae has proven to be very fruitful as well. The present review will discuss the main achievements of yeast-based studies in basic and applied virus research. These include the analysis of the function of individual proteins from important pathogenic viruses, the elucidation of key processes in viral replication through the development of systems that allow the replication of higher eukayotic viruses in yeast, and the use of yeast in antiviral drug development and vaccine production
Development, Disease, and Regeneration of Tissues in the Dental-Craniofacial Complex
This article has no abstract
Versatile Surface Electrodes for Combined Electrophysiology and Two-Photon Imaging of the Mouse Central Nervous System
Understanding and modulating CNS function in physiological as well as
pathophysiological contexts remains a significant ambition in research and clinical
applications. The investigation of the multifaceted CNS cell types including their
interactions and contributions to neural function requires a combination of the state-ofthe-art in vivo electrophysiology and imaging techniques. We developed a novel type of
liquid crystal polymer (LCP) surface micro-electrode manufactured in three customized
designs with up to 16 channels for recording and stimulation of brain activity. All designs
include spare central spaces for simultaneous 2P-imaging. Nanoporous platinumplated contact sites ensure a low impedance and high current transfer. The epidural
implantation of the LCP micro-electrodes could be combined with standard cranial
window surgery. The epidurally positioned electrodes did not only display long-term
biocompatibility, but we also observed an additional stabilization of the underlying CNS
tissue. We demonstrate the electrode’s versatility in combination with in vivo 2P-imaging
by monitoring anesthesia-awake cycles of transgenic mice with GCaMP3 expression
in neurons or astrocytes. Cortical stimulation and simultaneous 2P Ca2+ imaging in
neurons or astrocytes highlighted the astrocytes’ integrative character in neuronal activity
processing. Furthermore, we confirmed that spontaneous astroglial Ca2+ signals are
dampened under anesthesia, while evoked signals in neurons and astrocytes showed
stronger dependency on stimulation intensity rather than on various levels of anesthesia.
Finally, we show that the electrodes provide recordings of the electrocorticogram (ECoG) with a high signal-to noise ratio and spatial signal differences which help to decipher brain
activity states during experimental procedures. Summarizing, the novel LCP surface
micro-electrode is a versatile, convenient, and reliable tool to investigate brain function
in vivo
VARIABILITÉ GÉNÉTIQUE DU RENDEMENT A L'ABATTAGE ET DE LA COMPOSITION ANATOMIQUE DE LAPINS DE TROIS RACES
Variabilité génétique du rendement a l'abattage et de la composition anatomique de lapins de trois races
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