2,162 research outputs found
Nanophotonic boost of intermolecular energy transfer
We propose a scheme for efficient long-range energy transfer between two
distant light emitters separated by more than one wavelength of light, i.e.
much beyond the classical Forster radius. A hybrid nanoantenna-waveguide system
mediates the transmission of energy, showing enhancements up to 10^8 as
compared to vacuum. Our model shows how energy transfer in nanostructured media
can be boosted, beyond the simple donor Purcell enhancement, and in particular
for large donor-acceptor separations. The scheme we propose connects realistic
emitters and could lead to practical on-chip implementations.Comment: 9 pages, 4 figure
Optical amplification enhancement in photonic crystals
Improving and controlling the efficiency of a gain medium is one of the most
challenging problems of laser research. By measuring the gain length in an opal
based photonic crystal doped with laser dye, we demonstrate that optical
amplification is more than twenty-fold enhanced along the Gamma-K symmetry
directions of the face centered cubic photonic crystal. These results are
theoretically explained by directional variations of the density of states,
providing a quantitative connection between density of the states and light
amplification
Electrically injected cavity polaritons
We have realised a semiconductor quantum structure that produces
electroluminescence while operating in the light-matter strong coupling regime.
The mid-infrared light emitting device is composed of a quantum cascade
structure embedded in a planar microcavity, based on the GaAs/AlGaAs material
system. At zero bias, the structure is characterised using reflectivity
measurements which show, up to room temperature, a wide polariton anticrossing
between an intersubband transition and the resonant cavity photon mode. Under
electrical injection the spectral features of the emitted light change
drastically, as electrons are resonantly injected in a reduced part of the
polariton branches. Our experiment demonstrates that electrons can be
selectively injected into polariton states up to room temperature.Comment: 10 pages, 4 figure
Sensitivity and spectral control of network lasers
Recently, random lasing in complex networks has shown efficient lasing over more than 50 localised modes, promoted by multiple scattering over the underlying graph. If controlled, these network lasers can lead to fast-switching multifunctional light sources with synthesised spectrum. Here, we observe both in experiment and theory high sensitivity of the network laser spectrum to the spatial shape of the pump profile, with some modes for example increasing in intensity by 280% when switching off 7% of the pump beam. We solve the nonlinear equations within the steady state ab-initio laser theory (SALT) approximation over a graph and we show selective lasing of around 90% of the strongest intensity modes, effectively programming the spectrum of the lasing networks. In our experiments with polymer networks, this high sensitivity enables control of the lasing spectrum through non-uniform pump patterns. We propose the underlying complexity of the network modes as the key element behind efficient spectral control opening the way for the development of optical devices with wide impact for on-chip photonics for communication, sensing, and computation
The impact of trust on private equity contracts
This paper adresses the impact of trust on private equity contracts. Trust between investor and entrepreneur is essential to help overcome control problems, especially in an environment with severe agency risks and incomplete contracts. In this study, information about the effects of trust is collected using a simulation with 144 entrepreneurs and investors. We find that trust has an impact on the desired contracts of entrepreneurs, but not on that of investors. Our findings suggest that for parties, faced with potentially large agency problems (investors), trust and control seem to play complementary roles. On the other hand, for parties faced with smaller agency problems (entrepreneurs), trust seems to be a substitute for control
Strong enhancement of extremely energetic proton production in central heavy ion collisions at intermediate energy
The energetic proton emission has been investigated as a function of the
reaction centrality for the system 58Ni + 58Ni at 30A MeV. Extremely energetic
protons (EpNN > 130 MeV) were measured and their multiplicity is found to
increase almost quadratically with the number of participant nucleons thus
indicating the onset of a mechanism beyond one and two-body dynamics.Comment: 5 pages, 2 figures, submitted to Physical Review Letter
Psychopharmacology
Psychopharmacology is the scientific study of the effects drugs have on mood, sensation, thinking, and behavior. Particularly it concerns the use of medications in the treatment of mental disorders.
The goal of this chapter is to define the major classes of psychotropic drugs, introducing general pharmacological concepts, explaining the different mechanisms of action and the main clinical applications of the drugs used to treat psychiatric disorders.
Psychotropic drugs are commonly categorized according to their major clinical applications: antidepressants, anxiolytics, antipsychotics, and mood stabilizers. However, almost every drug used in psychiatry has multiple therapeutic roles and many clinical applications. For example, SSRIs are considered the first-line pharmacological treatment for several disorders, such as depressive disorders, anxiety disorders, and OCD. Similarly, antipsychotics are indicated as first-choice drugs for psychotic disorders, but many guidelines recommend their use, in combination with mood stabilizers, also in the treatment of acute mania
Contemporary presence of dynamical and statistical production of intermediate mass fragments in midperipheral Ni+Ni collisions at 30 MeV/nucleon
The reaction at 30 MeV/nucleon has been experimentally
investigated at the Superconducting Cyclotron of the INFN Laboratori Nazionali
del Sud. In midperipheral collisions the production of massive fragments
(4Z12), consistent with the statistical fragmentation of the
projectile-like residue and the dynamical formation of a neck, joining
projectile-like and target-like residues, has been observed. The fragments
coming from these different processes differ both in charge distribution and
isotopic composition. In particular it is shown that these mechanisms leading
to fragment production act contemporarily inside the same event.Comment: 9 pages, minor correction
Blastic plasmacytoid dendritic cell neoplasm: Genomics mark epigenetic dysregulation as a primary therapeutic target
Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare and aggressive hematologic malignancy for which there is still no effective B therapy. In order to identify genetic alterations useful for a new treatment design, we used whole-exome sequencing to analyze 14 BPDCN patients and the patient-derived CAL-1 cell line. The functional enrichment analysis of mutational data reported the epigenetic regulatory program to be the most significantly undermined (P<0.0001). In particular, twenty-five epigenetic modifiers were found mutated (e.g. ASXL1, TET2, SUZ12, ARID1A, PHF2, CHD8); ASXL1 was the most frequently affected (28.6% of cases). To evaluate the impact of the identified epigenetic mutations at the gene-expression and Histone H3 lysine 27 trimethylation/acetylation levels, we performed additional RNA and pathology tissue-chromatin immunoprecipitation sequencing experiments. The patients displayed enrichment in gene signatures regulated by methylation and modifiable by decitabine administration, shared common H3K27-acetylated regions, and had a set of cell-cycle genes aberrantly up-regulated and marked by promoter acetylation. Collectively, the integration of sequencing data showed the potential of a therapy based on epigenetic agents. Through the adoption of a preclinical BPDCN mouse model, established by CAL-1 cell line xenografting, we demonstrated the efficacy of the combination of the epigenetic drugs 5’-azacytidine and decitabine in controlling disease progression in vivo
Dye Stabilization and Wavelength Tunability in Lasing Fibers Based on DNA
Lasers based on biological materials are attracting an increasing interest in view of their use in integrated and transient photonics. Deoxyribonucleic acid (DNA) as optical biopolymer in combination with highly emissive dyes has been reported to have excellent potential in this respect. However, achieving miniaturized lasing systems based on solid-state DNA shaped in different geometries to confine and enhance emission is still a challenge, and the physicochemical mechanisms originating fluorescence enhancement are not fully understood. Herein, a class of wavelength-tunable lasers based on DNA nanofibers is demonstrated, for which optical properties are highly controlled through the system morphology. A synergistic effect is highlighted at the basis of lasing action. Through a quantum chemical investigation, it is shown that the interaction of DNA with the encapsulated dye leads to hindered twisting and suppressed channels for the nonradiative decay. This is combined with effective waveguiding, optical gain, and tailored mode confinement to promote morphologically controlled lasing in DNA-based nanofibers. The results establish design rules for the development of bright and tunable nanolasers and optical networks based on DNA nanostructures
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