Hybrid materials taking advantage of the different physical properties of materials are highly attractive for numerous applications in today's science and technology. Here, it is demonstrated that epitaxial bi-domain III-V/Si are hybrid structures, composed of bulk photo-active semiconductors with 2D topological semi-metallic vertical inclusions, endowed with ambipolar properties. By combining structural, transport, and photoelectrochemical characterizations with first-principle calculations, it is shown that the bi-domain III-V/Si materials are able within the same layer to absorb light efficiently, separate laterally the photo-generated carriers, transfer them to semimetal singularities, and ease extraction of both electrons and holes vertically, leading to efficient carrier collection.
View Article and Find Full Text PDFClass A shot-noise limited operation is achieved in an electrically pumped vertical external cavity surface emitting laser (VECSEL), opening the way for integration of such peculiar noiseless laser oscillation in applications where low power consumption and footprint are mandatory. The quantum well active medium is grown on an InP substrate to enable laser oscillation at telecom wavelengths. Single frequency class A operation is obtained by proper optimization of the cavity dimensions, ensuring at the same time a sufficiently long and high-finesse cavity without any intracavity filtering components.
View Article and Find Full Text PDFThe health check-up is an opportunity for the general practitioner to carry out preventive measures and screening. Like any other patient, adults with intellectual and developmental disabilities must have access to it without discrimination. The preventive recommendations for people with disabilities follow those of the general population with some specificities, in particular the prevention of sensory disability, attention to the underestimated health problems in this population and those associated with the handicap.
View Article and Find Full Text PDFHighly polar materials are usually preferred over weakly polar ones to study strong electron-phonon interactions and its fascinating properties. Here, we report on the achievement of simultaneous confinement of charge carriers and phonons at the vicinity of a 2D vertical homovalent singularity (antiphase boundary, APB) in an (In,Ga)P/SiGe/Si sample. The impact of the electron-phonon interaction on the photoluminescence processes is then clarified by combining transmission electron microscopy, X-ray diffraction, calculations, Raman spectroscopy, and photoluminescence experiments.
View Article and Find Full Text PDFThe etiologies of undifferentiated fever in pregnant women have not been studied thoroughly. Because of its non-specific presentation but severe prognosis, listeriosis is often suspected in this setting, but in most cases not confirmed. We studied the causes of undifferentiated fever in pregnant women who received preemptive listeriosis treatment.
View Article and Find Full Text PDFBackground: Automated medical history-taking devices (AMHTDs) are emerging tools with the potential to increase the quality of medical consultations by providing physicians with an exhaustive, high-quality, standardized anamnesis and differential diagnosis.
Objective: This study aimed to assess the effectiveness of an AMHTD to obtain an accurate differential diagnosis in an outpatient service.
Methods: We conducted a pilot randomized controlled trial involving 59 patients presenting to an emergency outpatient unit and suffering from various conditions affecting the limbs, the back, and the chest wall.
Spectral dependence of Lamb coupling constant C is experimentally investigated in an InGaAlAs Quantum Wells active medium. An Optically-Pumped Vertical-External-Cavity Surface-Emitting Laser is designed to sustain the oscillation of two orthogonally polarized modes sharing the same active region while separated in the rest of the cavity. This laser design enables to tune independently the two wavelengths and, at the same time, to apply differential losses in order to extract without any extrapolation the actual coupling constant.
View Article and Find Full Text PDFLiquid crystal (LC) microcells monolithically integrated on the surface of InGaAs based photodiodes (PDs) are demonstrated. These LC microcells acting as tunable Fabry-Perot filters exhibit a wavelength tunability of more than 100 nm around 1550 nm with less than 10V applied voltage. Using a tunable laser operating in the S and C bands, photocurrent measurements are performed.
View Article and Find Full Text PDFWe investigated deformation of InP that was introduced by thin, narrow, dielectric SiN stripes on the (100) surface of InP substrates. Quantitative optical measurements were performed using two different techniques based on luminescence from the InP: first, by degree of polarization of photoluminescence; and second, by cathodoluminescence spectroscopy. The two techniques provide complementary information on deformation of the InP and thus together provide a means to evaluate approaches to simulation of the deformation owing to dielectric stripes.
View Article and Find Full Text PDFJ Hist Biol
September 2018
This paper aims at bridging a gap between the history of American animal behavior studies and the history of sociobiology. In the post-war period, ecology, comparative psychology and ethology were all investigating animal societies, using different approaches ranging from fieldwork to laboratory studies. We argue that this disunity in "practices of place" (Kohler, Robert E.
View Article and Find Full Text PDFA continuous-wave 1.6 µm-emitting InAs Quantum Dash-based Optically-Pumped Vertical-External-Cavity Surface-Emitting Laser on InP is demonstrated. The laser emits in the L-band with a stable linear polarization.
View Article and Find Full Text PDFThe social and neural sciences share a common interest in understanding the mechanisms that underlie human behaviour. However, interactions between neuroscience and social science disciplines remain strikingly narrow and tenuous. We illustrate the scope and challenges for such interactions using the paradigmatic example of neuroeconomics.
View Article and Find Full Text PDFWe present a quantitative study on the fabrication of microlenses using a low-cost polymer dispending technique. Our method is based on the use of a silicon micro-cantilever robotized spotter system. We first give a detailed description of the technique.
View Article and Find Full Text PDFWe demonstrate what we believe is the first nonmechanical tunable vertical-cavity surface-emitting laser operating in the C band. This was achieved as a result of the combination of an InGaAs quantum well structure with a 6lambda thickness tunable index nano-polymer-dispersed liquid-crystal material. Experimental results exhibited a potential tunable range close to 10 nm, in the preliminary version, and excellent single mode locking due to the side-mode suppression ratio (more than 20 dB) over the whole spectral range.
View Article and Find Full Text PDFMixed glial neuronal cultures prepared from rat embryonic cortical cells were either treated with aracytosine or infected with an adenovirus encoding the Lac-Z gene according to two protocols of infection. In each experiment, 24 h before the end of the incubation period, [35S]methionine was added to one set of cultures which were performed in plastic chamber slides. At 10-13 days in vitro, control and treated cultures were processed either for immunocytochemical detection of neuron-specific enolase (NSE)-stained cells or for measurement of [35S]methionine incorporation.
View Article and Find Full Text PDFThe adenovirus carrying a reporter gene--the Lac Z gene--is known to infect central nervous system (CNS) cells in primary cell cultures. The percentage of infected neurons with respect to the total number of neurons was studied in primary dissociated cultures as a function of the day of inoculation and the age of three rat CNS cultures: spinal cord, mesencephalon and cortex. Two methods of viral inoculation were compared: the first inoculation was performed on the cultured cell at 2, 3 or 6 days in vitro (DIV) whereas the second inoculation was performed on the cell suspensions before seeding.
View Article and Find Full Text PDFJ Chem Neuroanat
March 1998
Here, functional AMPA/kainate receptors in human embryonic (5.5-7.5 gestational weeks) and foetal (8-10 gestational weeks) central nervous system tissue, shown by the cobalt labeling method, are reported.
View Article and Find Full Text PDFPrimary dissociated cultures of rhombencephalon were prepared from 5-9-week-old human fetuses. Half of some cultures were treated by two non-competitive N-methyl-D-aspartate antagonists, namely 1-(2-thienyl)cyclohexylpiperidine (TCP) and cis-Pip/Mel-[1-(2-thienyl)-2-methyl-cyclohexyl]piperidine (GK11) in negative enantiomeric form, which enhance the survival of human fetal central nervous system cells in culture. At different days in vitro, the treated and the control cultures were processed for immunocytochemical detection of serotonin-containing neurons which were studied by morphological and morphometric analysis.
View Article and Find Full Text PDFAn adenovirus encoding tyrosine hydroxylase (TH) activity was inserted in neuronal and glial cultured cells obtained from human fetal central nervous system (CNS) tissue. Using a double fluorescence immunostaining, we characterized inoculated CNS cells, with a TH antiserum and one of the following antibodies: microtubule-associated protein (MAP2) and GABA for neuronal cells, vimentin (Vim) for glial cells and glial fibrillary acidic protein (GFAP) for astrocytes. The characterization of inoculated neuronal cells was established by the detection of TH-MAP2-stained neurons in cultures obtained from the thoracic and lumbar parts of the spinal cord where no intrinsic TH cells are described.
View Article and Find Full Text PDFDissociated cell cultures were prepared from brainstems of 5- to 10-week-old human fetuses. Catecholamine- as well as indolamine-containing cells were visualized using respectively dopamine (DA), noradrenaline (NA) and serotonin (5HT) as immunocytochemical markers. NA-, DA-, and 5HT-stained cells were characterized in the rhombencephalic cultures, representing respectively the fetal localization of the locus coeruleus and raphe nuclei.
View Article and Find Full Text PDFThe non-competitive N-methyl-D-aspartate antagonist cis-Pip/Me 1-[1-(2-thienyl)-2-methyl-cyclohexyl] piperidine (GK11) either in racemic(+/-) or (-) enantiomeric form has been investigated on survival of human fetal spinal cord cells in culture. The treated cultured cells were processed for immunocytochemical detection of GABA at different time intervals ranging from 3 to 27 weeks. The number of GABA-stained cells was found to be greater in the treated cultures than in the control ones.
View Article and Find Full Text PDFPrimary dissociated cultures of human fetal central nervous system cells were prepared and inoculated at different days in vitro with adenovirus that contained a reporter gene encoding beta-galactosidase. At various time intervals, the cultures were processed for characterization with X-gal histochemistry and additional immunostaining with neurofilament (NF), GABA and glial fibrillary acidic protein (GFA-P). We observed that NF (+) and GABA (+) neuronal as well as GFA-P (+) glial cells could express beta-galactosidase activity after inoculation.
View Article and Find Full Text PDFCD4 is a member of the Ig gene super family expressed on the surface of many thymocytes and of a subset of T lymphocytes. Human CD4 is the receptor for HIV envelope glycoprotein gp120. Human and mouse CD4 transcripts are expressed in human and mouse central nervous system (CNS), but no corresponding proteins have been reported yet.
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