104 research outputs found
Electric field sensing with a scanning fiber-coupled quantum dot
We demonstrate the application of a fiber-coupled quantum-dot-in-a-tip as a
probe for scanning electric field microscopy. We map the out-of-plane component
of the electric field induced by a pair of electrodes by measurement of the
quantum-confined Stark effect induced on a quantum dot spectral line. Our
results are in agreement with finite element simulations of the experiment.
Furthermore, we present results from analytic calculations and simulations
which are relevant to any electric field sensor embedded in a dielectric tip.
In particular, we highlight the impact of the tip geometry on both the
resolution and sensitivity.Comment: 10 pages, 4 figure
Anapole nanolasers for mode-locking and ultrafast pulse generation
Nanophotonics is a rapidly developing field of research with many suggestions for a design of nanoantennas, sensors and miniature metadevices. Despite many proposals for passive nanophotonic devices, the efficient coupling of light to nanoscale optical structures remains a major challenge. In this article, we propose a nanoscale laser based on a tightly confined anapole mode. By harnessing the non-radiating nature of the anapole state, we show how to engineer nanolasers based on InGaAs nanodisks as on-chip sources with unique optical properties. Leveraging on the near-field character of anapole modes, we demonstrate a spontaneously polarized nanolaser able to couple light into waveguide channels with four orders of magnitude intensity than classical nanolasers, as well as the generation of ultrafast (of 100 fs) pulses via spontaneous mode locking of several anapoles. Anapole nanolasers offer an attractive platform for monolithically integrated, silicon photonics sources for advanced and efficient nanoscale circuitry
Neuropeptide S-Mediated Facilitation of Synaptic Transmission Enforces Subthreshold Theta Oscillations within the Lateral Amygdala
The neuropeptide S (NPS) receptor system modulates neuronal circuit activity in
the amygdala in conjunction with fear, anxiety and the expression and extinction
of previously acquired fear memories. Using in vitro brain
slice preparations of transgenic GAD67-GFP (Δneo) mice, we investigated the
effects of NPS on neural activity in the lateral amygdala as a key region for
the formation and extinction of fear memories. We are able to demonstrate that
NPS augments excitatory glutamatergic synaptic input onto both projection
neurons and interneurons of the lateral amygdala, resulting in enhanced spike
activity of both types of cells. These effects were at least in part mediated by
presynaptic mechanisms. In turn, inhibition of projection neurons by local
interneurons was augmented by NPS, and subthreshold oscillations were
strengthened, leading to their shift into the theta frequency range. These data
suggest that the multifaceted effects of NPS on amygdaloid circuitry may shape
behavior-related network activity patterns in the amygdala and reflect the
peptide's potent activity in various forms of affective behavior and
emotional memory
The STRATOB study: design of a randomized controlled clinical trial of Cognitive Behavioral Therapy and Brief Strategic Therapy with telecare in patients with obesity and binge-eating disorder referred to residential nutritional rehabilitation
bstract
BACKGROUND:
Overweight and obesity are linked with binge eating disorder (BED). Effective interventions to significantly reduce weight, maintain weight loss and manage associated pathologies like BED are typically combined treatment options (dietetic, nutritional, physical, behavioral, cognitive-behavioral, pharmacological, surgical). Significant difficulties with regard to availability, costs, treatment adherence and long-term efficacy are present. Particularly Cognitive Behavioral Therapy (CBT) is the therapeutic approach indicated both in in-patient and in out-patient settings for BED. In recent years systemic and systemic-strategic psychotherapies have been implemented to treat patients with obesity and BED involved in familiar problems. Particularly a brief protocol for the systemic-strategic treatment of BED, using overall the strategic dialogue, has been recently developed. Moreover telemedicine, a new promising low cost method, has been used for obesity with BED in out-patient settings in order to avoid relapse after the in-patient step of treatment and to keep on a continuity of care with the involvement of the same clinical in-patient team.
METHODS:
The comparison between CBT and Brief Strategic Therapy (BST) will be assessed in a two-arm randomized controlled clinical trial. Due to the novelty of the application of BST in BED treatment (no other RCTs including BST have been carried out), a pilot study will be carried out before conducting a large scale randomized controlled clinical trial (RCT). Both CBT and BST group will follow an in-hospital treatment (diet, physical activity, dietitian counseling, 8 psychological sessions) plus 8 out-patient telephone-based sessions of psychological support and monitoring with the same in-patient psychotherapists. Primary outcome measure of the randomized trial will be the change in the Global Index of the Outcome Questionnaire (OQ-45.2). Secondary outcome measures will be the percentage of BED patients remitted considering the number of weekly binge episodes and the weight loss. Data will be collected at baseline, at discharge from the hospital (c.a. 1 month after) and after 6-12-24 months from the end of the in-hospital treatment. Data at follow-up time points will be collected through tele-sessions.
DISCUSSION:
The STRATOB (Systemic and STRATegic psychotherapy for OBesity), a comprehensive two-phase stepped down program enhanced by telepsychology for the medium-term treatment of obese people with BED seeking intervention for weight loss, will shed light about the comparison of the effectiveness of the BST with the gold standard CBT and about the continuity of care at home using a low-level of telecare (mobile phones).
TRIAL REGISTRATION:
ClinicalTrials.gov Identifier: NCT0109625
Linearly Polarized Emission from an Embedded Quantum Dot Using Nanowire Morphology Control
GaAs nanowires with elongated cross sections are formed using a catalyst-free growth technique. This is achieved by patterning elongated nanoscale openings within a silicon dioxide growth mask on a (111)B GaAs substrate. It is observed that MOVPE-grown vertical nanowires with cross section elongated in the [21̅1̅] and [1̅12] directions remain faithful to the geometry of the openings. An InGaAs quantum dot with weak radial confinement is realized within each nanowire by briefly introducing indium into the reactor during nanowire growth. Photoluminescence emission from an embedded nanowire quantum dot is strongly linearly polarized (typically >90%) with the polarization direction coincident with the axis of elongation. Linearly polarized PL emission is a result of embedding the quantum dot in an anisotropic nanowire structure that supports a single strongly confined, linearly polarized optical mode. This research provides a route to the bottom-up growth of linearly polarized single photon sources of interest for quantum information applications
Effects of elevated seawater pCO2 on gene expression patterns in the gills of the green crab, Carcinus maenas
Background: The green crab Carcinus maenas is known for its high acclimation potential to varying environmental
abiotic conditions. A high ability for ion and acid-base regulation is mainly based on an efficient regulation
apparatus located in gill epithelia. However, at present it is neither known which ion transport proteins play a key
role in the acid-base compensation response nor how gill epithelia respond to elevated seawater pCO2 as
predicted for the future. In order to promote our understanding of the responses of green crab acid-base
regulatory epithelia to high pCO2, Baltic Sea green crabs were exposed to a pCO2 of 400 Pa. Gills were screened
for differentially expressed gene transcripts using a 4,462-feature microarray and quantitative real-time PCR.
Results: Crabs responded mainly through fine scale adjustment of gene expression to elevated pCO2. However, 2%
of all investigated transcripts were significantly regulated 1.3 to 2.2-fold upon one-week exposure to CO2 stress.
Most of the genes known to code for proteins involved in osmo- and acid-base regulation, as well as cellular stress
response, were were not impacted by elevated pCO2. However, after one week of exposure, significant changes
were detected in a calcium-activated chloride channel, a hyperpolarization activated nucleotide-gated potassium
channel, a tetraspanin, and an integrin. Furthermore, a putative syntaxin-binding protein, a protein of the
transmembrane 9 superfamily, and a Cl-/HCO3
- exchanger of the SLC 4 family were differentially regulated. These
genes were also affected in a previously published hypoosmotic acclimation response study.
Conclusions: The moderate, but specific response of C. maenas gill gene expression indicates that (1) seawater
acidification does not act as a strong stressor on the cellular level in gill epithelia; (2) the response to hypercapnia
is to some degree comparable to a hypoosmotic acclimation response; (3) the specialization of each of the
posterior gill arches might go beyond what has been demonstrated up to date; and (4) a re-configuration of gill
epithelia might occur in response to hypercapnia
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