Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 231
Filter
1.
Acta Neurochir (Wien) ; 166(1): 139, 2024 Mar 15.
Article in English | MEDLINE | ID: mdl-38488893

ABSTRACT

Neurovascular compression of the rostral ventrolateral medulla (RVLM) has been described as a possible cause of refractory essential hypertension. We present the case of a patient affected by episodes of severe paroxysmal hypertension, some episodes associated with vago-glossopharyngeal neuralgia. Classical secondary forms of hypertension were excluded. Imaging revealed a neurovascular conflict between the posterior inferior cerebellar artery (PICA) and the ventrolateral medulla at the level of the root entry zone of the ninth and tenth cranial nerves (CN IX-X REZ). A MVD of a conflict between the PICA and the RVLM and adjacent CN IX-X REZ was performed, resulting in reduction of the frequency and severity of the episodes. Brain MRI should be performed in cases of paroxysmal hypertension. MVD can be considered in selected patients.


Subject(s)
Glossopharyngeal Nerve Diseases , Hypertension , Humans , Medulla Oblongata/diagnostic imaging , Hypertension/complications , Vagus Nerve , Pressure
2.
Int Wound J ; 20(7): 2540-2550, 2023 Sep.
Article in English | MEDLINE | ID: mdl-37020423

ABSTRACT

Peristomal skin complications (PSCs) have a significant impact on quality of life and ostomy treatment costs. This study aimed to assess the healthcare resource use for patients with an ileostomy and PSCs symptoms. Two surveys were developed and, after validation by healthcare professionals and patients, data were collected on healthcare resource use while not experiencing any PSCs symptoms and while experiencing complications of various severities, as defined by the modified Ostomy Skin Tool. Costs applied to resource use were assigned from relevant United Kingdom sources. Additional healthcare resource use associated with PSCs, relative to no complications, was estimated to result in a total cost per instance of £258, £383, and £505 for mild, moderate, or severe PSC, respectively. The average estimated total cost per complication instance, weighted across mild, moderate, and severe PSCs, was £349. Severe-level PSCs were associated with the highest cost, because of the treatment-level required and the longer duration of symptoms. There is potential for clinical benefits and economising in stoma care if interventions are implemented that reduce the incidence and/or severity of PSCs.


Subject(s)
Ileostomy , Skin Diseases , Humans , Ileostomy/adverse effects , Quality of Life , Postoperative Complications/etiology , Skin Diseases/etiology , Health Care Costs , Skin Care
3.
Phys Rev Lett ; 129(9): 093603, 2022 Aug 26.
Article in English | MEDLINE | ID: mdl-36083685

ABSTRACT

Semiconductor microresonators embedding quantum wells can host tightly confined and mutually interacting excitonic, optical, and mechanical modes at once. We theoretically investigate the case where the system operates in the strong exciton-photon coupling regime, while the optical and excitonic resonances are parametrically modulated by the interaction with a mechanical mode. Owing to the large exciton-phonon coupling at play in semiconductors, we predict an enhancement of polariton-phonon interactions by 2 orders of magnitude with respect to mere optomechanical coupling: a near-unity single-polariton quantum cooperativity is within reach for current semiconductor resonator platforms. We further analyze how polariton nonlinearities affect dynamical backaction, modifying the capability to cool or amplify the mechanical motion.

4.
Phys Rev Lett ; 126(12): 127403, 2021 Mar 26.
Article in English | MEDLINE | ID: mdl-33834841

ABSTRACT

Topological materials rely on engineering global properties of their bulk energy bands called topological invariants. These invariants, usually defined over the entire Brillouin zone, are related to the existence of protected edge states. However, for an important class of Hamiltonians corresponding to 2D lattices with time-reversal and chiral symmetry (e.g., graphene), the existence of edge states is linked to invariants that are not defined over the full 2D Brillouin zone, but on reduced 1D subspaces. Here, we demonstrate a novel scheme based on a combined real- and momentum-space measurement to directly access these 1D topological invariants in lattices of semiconductor microcavities confining exciton polaritons. We extract these invariants in arrays emulating the physics of regular and critically compressed graphene where Dirac cones have merged. Our scheme provides a direct evidence of the bulk-edge correspondence in these systems and opens the door to the exploration of more complex topological effects, e.g., involving disorder and interactions.

5.
Phys Rev Lett ; 125(18): 186601, 2020 Oct 30.
Article in English | MEDLINE | ID: mdl-33196264

ABSTRACT

Compression dramatically changes the transport and localization properties of graphene. This is intimately related to the change of symmetry of the Dirac cone when the particle hopping is different along different directions of the lattice. In particular, for a critical compression, a semi-Dirac cone is formed with massless and massive dispersions along perpendicular directions. Here we show direct evidence of the highly anisotropic transport of polaritons in a honeycomb lattice of coupled micropillars implementing a semi-Dirac cone. If we optically induce a vacancylike defect in the lattice, we observe an anisotropically localized polariton distribution in a single sublattice, a consequence of the semi-Dirac dispersion. Our work opens up new horizons for the study of transport and localization in lattices with chiral symmetry and exotic Dirac dispersions.

6.
Integr Org Biol ; 2(1): obaa020, 2020.
Article in English | MEDLINE | ID: mdl-33791561

ABSTRACT

Mammalian molar crowns form a module in which measurements of size for individual teeth within a tooth row covary with one another. Molar crown size covariation is proposed to fit the inhibitory cascade model (ICM) or its variant the molar module component (MMC) model, but the inability of the former model to fit across biological scales is a concern in the few cases where it has been tested in Primates. The ICM has thus far failed to explain patterns of intraspecific variation, an intermediate biological scale, even though it explains patterns at both smaller organ-level and larger between-species biological scales. Studies of this topic in a much broader range of taxa are needed, but the properties of a sample appropriate for testing the ICM at the intraspecific level are unclear. Here, we assess intraspecific variation in relative molar sizes of the cotton mouse, Peromyscus gossypinus, to further test the ICM and to develop recommendations for appropriate sampling protocols in future intraspecific studies of molar size variation across Mammalia. To develop these recommendations, we model the sensitivity of estimates of molar ratios to sample size and simulate the use of composite molar rows when complete ones are unavailable. Similar to past studies on primates, our results show that intraspecific variance structure of molar ratios within the rodent P. gossypinus does not meet predictions of the ICM or MMC. When we extend these analyses to include the MMC, one model does not fit observed patterns of variation better than the other. Standing variation in molar size ratios is relatively constant across mammalian samples containing all three molars. In future studies, analyzing average ratio values will require relatively small minimum sample sizes of two or more complete molar rows. Even composite-based estimates from four or more specimens per tooth position can accurately estimate mean molar ratios. Analyzing variance structure will require relatively large sample sizes of at least 40-50 complete specimens, and composite molar rows cannot accurately reconstruct variance structure of ratios in a sample. Based on these results, we propose guidelines for intraspecific studies of molar size covariation. In particular, we note that the suitability of composite specimens for averaging mean molar ratios is promising for the inclusion of isolated molars and incomplete molar rows from the fossil record in future studies of the evolution of molar modules, as long as variance structure is not a key component of such studies.

7.
Phys Rev Lett ; 123(11): 113901, 2019 Sep 13.
Article in English | MEDLINE | ID: mdl-31573264

ABSTRACT

Phase frustration in periodic lattices is responsible for the formation of dispersionless flatbands. The absence of any kinetic energy scale makes flatband physics critically sensitive to perturbations and interactions. We report on the experimental investigation of the nonlinear response of cavity polaritons in the gapped flatband of a one-dimensional Lieb lattice. We observe the formation of gap solitons with quantized size and abrupt edges, a signature of the frozen propagation of switching fronts. This type of gap soliton belongs to the class of truncated Bloch waves, and has only been observed in closed systems up to now. Here, the driven-dissipative character of the system gives rise to a complex multistability of the flatband nonlinear domains. These results open up an interesting perspective regarding more complex 2D lattices and the generation of correlated photon phases.

8.
Opt Lett ; 44(18): 4531-4534, 2019 Sep 15.
Article in English | MEDLINE | ID: mdl-31517923

ABSTRACT

Light's orbital angular momentum (OAM) is an unbounded degree of freedom emerging in helical beams that appears very advantageous technologically. Using chiral microlasers, i.e., integrated devices that allow generating an emission carrying a net OAM, we demonstrate a regime of bistability involving two modes presenting distinct OAM (ℓ=0 and ℓ=2). Furthermore, thanks to an engineered spin-orbit coupling of light in these devices, these modes also exhibit distinct polarization patterns, i.e., circular and azimuthal polarizations. Using a dynamical model of rate equations, we show that this bistability arises from polarization-dependent saturation of the gain medium. Such a bistable regime appears very promising for implementing ultrafast optical switches based on the OAM of light. As well, it paves the way for the exploration of dynamical processes involving phase and polarization vortices.

9.
Clin Toxicol (Phila) ; 56(8): 790-794, 2018 08.
Article in English | MEDLINE | ID: mdl-29323540

ABSTRACT

CONTEXT: Among the numerous varieties of squash that exist, some are edible while other bitter-tasting ones are not fit for human consumption. Cases of confusion seem to be multiplying and are characterized by digestive problems (diarrhea, vomiting, and abdominal pain). METHODS: This is a descriptive retrospective study of cases of exposure reported to French Poison Control Centers between 1 January 2012 and 12 December 2016. RESULTS: 353 patients were included, with 71.7% belonging to collective cases of poisoning. The male to female sex ratio was 0.75 for an average age of 38.2 ± 23.6 years. The circumstances of exposure were dietary for 337 patients (95.5%). The majority of the squash consumed was purchased at a store (55.8%) but some also came from the garden (25.5%). 204 patients (57.8%) mostly presented with diarrhea, vomiting, abdominal pain, sometimes with the consequent dehydration, hypotension, tachycardia, headaches, or vertigo. There were no deaths or severe (Poisoning Severity Score (PSS) 3) cases, but there were 14 patients (4.0%) of moderate severity, 190 patients (53.8%) of minor severity (PSS 1), and 149 patients (42.2%) without severity (PSS 0) but among which we include the bitter taste of the squash. The average age of PSS 2 patients was significantly (p = .003) older than that of the PSS <2 patients. CONCLUSION: As the first consequential series in Europe, our study shows that exposure to non-edible squash is frequent. Usually benign, poisoning could be the consequence of the irritating effect of certain cucurbits, the molecules responsible for the taste and toxicity of the fruits. In terms of prevention therefore, we recommend disposing of any squash with a bitter taste.


Subject(s)
Cucurbita/poisoning , Fruit/poisoning , Poison Control Centers/statistics & numerical data , Poisoning/epidemiology , Adolescent , Adult , Aged , Aged, 80 and over , Child , Child, Preschool , Female , France/epidemiology , Humans , Infant , Male , Middle Aged , Retrospective Studies , Young Adult
10.
Biomicrofluidics ; 11(1): 014104, 2017 Jan.
Article in English | MEDLINE | ID: mdl-28798839

ABSTRACT

We report a simple, efficient, one-step, affordable method to produce open-channel paper-based microfluidic channels. One surface of a sheet of paper is selectively calendared, with concomitant hydrophobization, to create the microfluidic channel. Our method involves asymmetric mechanical modification of a paper surface using a rolling ball (ball-point pen) under a controlled amount of applied stress (σz) to ascertain that only one side is modified. A lubricating solvent (hexane) aids in the selective deformation. The lubricant also serves as a carrier for a perfluoroalkyl trichlorosilane allowing the channel to be made hydrophobic as it is formed. For brevity and clarity, we abbreviated this method as TACH (Targeted Asymmetric Calendaring and Hydrophobization). We demonstrate that TACH can be used to reliably produce channels of variable widths (size of the ball) and depths (number of passes), without affecting the nonworking surface of the paper. Using tomography, we demonstrate that these channels can vary from 10s to 100s of microns in diameter. The created hydrophobic barrier extends around the channel through wicking to ensure no leakages. We demonstrate, through modeling and fabrication, that flow properties of the resulting channels are analogous to conventional devices and are tunable based on associated dimensionless numbers.

11.
Phys Rev Lett ; 118(24): 247402, 2017 Jun 16.
Article in English | MEDLINE | ID: mdl-28665653

ABSTRACT

We experimentally explore the dynamical optical hysteresis of a semiconductor microcavity as a function of the sweep time. The hysteresis area exhibits a double power law decay due to the influence of fluctuations, which trigger switching between metastable states. Upon increasing the average photon number and approaching the thermodynamic limit, the double power law evolves into a single power law. This algebraic behavior characterizes a dissipative phase transition. Our findings are in good agreement with theoretical predictions for a single mode resonator influenced by quantum fluctuations, and the present experimental approach is promising for exploring critical phenomena in photonic lattices.

12.
Phys Rev Lett ; 118(10): 107403, 2017 Mar 10.
Article in English | MEDLINE | ID: mdl-28339267

ABSTRACT

We experimentally reveal the emergence of edge states in a photonic lattice with orbital bands. We use a two-dimensional honeycomb lattice of coupled micropillars whose bulk spectrum shows four gapless bands arising from the coupling of p-like photonic orbitals. We observe zero-energy edge states whose topological origin is similar to that of conventional edge states in graphene. Additionally, we report novel dispersive edge states in zigzag and armchair edges. The observations are reproduced by tight-binding and analytical calculations, which we extend to bearded edges. Our work shows the potentiality of coupled micropillars in elucidating some of the electronic properties of emergent two-dimensional materials with orbital bands.

13.
Brain Struct Funct ; 222(3): 1193-1206, 2017 04.
Article in English | MEDLINE | ID: mdl-27394722

ABSTRACT

In the context of an autologous adult neural cell ecosystem (ANCE) transplantation study, four intact adult female macaque monkeys underwent a unilateral biopsy of the dorsolateral prefrontal cortex (dlPFC) to provide the cellular material needed to obtain the ANCE. Monkeys were previously trained to perform quantitative motor (manual dexterity) tasks, namely, the "modified-Brinkman board" task and the "reach and grasp drawer" task. The aim of the present study was to extend preliminary data on the role of the prefrontal cortex in motor habit and test the hypothesis that dlPFC contributes to predict the grip force required when a precise level of force to be generated is known beforehand. As expected for a small dlPFC biopsy, neither the motor performance (score) nor the spatiotemporal motor sequences were affected in the "modified-Brinkman board" task, whereas significant changes (mainly decreases) in the maximal grip force (force applied on the drawer knob) were observed in the "reach and grasp drawer" task. The present data in the macaque monkey related to the prediction of grip force are well in line with the previous fMRI data reported for human subjects. Moreover, the ANCE transplantation strategy (in the case of stroke or Parkinson's disease) based on biopsy in dlPFC does not generate unwanted motor consequences, at least as far as motor habit and motor performance are concerned in the context of a sequential grasping a small objects, which does not require the development of significant force levels.


Subject(s)
Habituation, Psychophysiologic/physiology , Hand Strength/physiology , Motor Activity/physiology , Prefrontal Cortex/physiology , Psychomotor Performance/physiology , Animals , Female , Functional Laterality , Image Processing, Computer-Assisted , Macaca fascicularis , Magnetic Resonance Imaging , Prefrontal Cortex/diagnostic imaging , Range of Motion, Articular/physiology
14.
Phys Rev Lett ; 117(21): 217401, 2016 Nov 18.
Article in English | MEDLINE | ID: mdl-27911548

ABSTRACT

We use a one-dimensional polariton fluid in a semiconductor microcavity to explore the nonlinear dynamics of counterpropagating interacting Bose fluids. The intrinsically driven-dissipative nature of the polariton fluid allows us to use resonant pumping to impose a phase twist across the fluid. When the polariton-polariton interaction energy becomes comparable to the kinetic energy, linear interference fringes transform into a train of solitons. A novel type of bistable behavior controlled by the phase twist across the fluid is experimentally evidenced.

15.
Nat Commun ; 7: 11887, 2016 06 16.
Article in English | MEDLINE | ID: mdl-27307038

ABSTRACT

The Bose-Hubbard model (BHM) describes bosons hopping across sites and interacting on-site. Inspired by the success of BHM simulators with atoms in optical lattices, proposals for implementing the BHM with photons in coupled nonlinear cavities have recently emerged. Two coupled semiconductor microcavities constitute a model system where the hopping, interaction and decay of exciton polaritons-mixed light-matter quasiparticles-can be engineered in combination with site-selective coherent driving to implement the driven-dissipative two-site optical BHM. Here we explore the interplay of interference and nonlinearity in this system, in a regime where three distinct density profiles can be observed under identical driving conditions. We demonstrate how the phase acquired by polaritons hopping between cavities can be controlled through polariton-polariton interactions. Our results open new perspectives for synthesizing density-dependent gauge fields using polaritons in two-dimensional multicavity systems.

16.
Phys Rev Lett ; 116(6): 066402, 2016 Feb 12.
Article in English | MEDLINE | ID: mdl-26919002

ABSTRACT

We report on the engineering of a nondispersive (flat) energy band in a geometrically frustrated lattice of micropillar optical cavities. By taking advantage of the non-Hermitian nature of our system, we achieve bosonic condensation of exciton polaritons into the flat band. Because of the infinite effective mass in such a band, the condensate is highly sensitive to disorder and fragments into localized modes reflecting the elementary eigenstates produced by geometric frustration. This realization offers a novel approach to studying coherent phases of light and matter under the controlled interplay of frustration, interactions, and dissipation.

18.
Curr Treat Options Neurol ; 17(9): 373, 2015 Sep.
Article in English | MEDLINE | ID: mdl-26257150

ABSTRACT

OPINION STATEMENT: The diagnosis and appropriate treatment of hyperkinetic movement disorders require a work up of potentially reversible metabolic, infectious and structural disorders as well as side effects of current medication. In pharmacoresistant movement disorders with a disabling impact on quality of life, deep brain stimulation (DBS) should be considered. At different targets, DBS has become an established therapy for Parkinson's disease (GPi-STN), tremor (VIM) and primary dystonia (GPi) with reasonable perioperative risks and side effects, established guidelines and some clinical and radiological predictive factors. In contrast, for other hyperkinetic movement disorders, including secondary dystonia, Gilles de la Tourette, chorea and ballism, only few data are available. Definite targets are not well defined, and reported results are of less magnitude than those of the recognized indications. In this expanding therapeutical field without worked out recommendations, an individual approach is needed with DBS indication assessment only after rigorous multidisciplinary scrutiny, restricted to expert centres.

19.
Arch Pediatr ; 22(3): 223-34, 2015 Mar.
Article in French | MEDLINE | ID: mdl-25656456

ABSTRACT

Studies on mild intellectual disability (MID) are scarce. The aim of this study was to describe the educational and medical care trajectories and their determinants in children with MID. The study population concerned children born in 1997 and resident in a French county (Isère) in 2008. MID was defined as an overall IQ score between 50 and 69. For the present study, this definition was adjusted by integrating the IQ confidence intervals so that the risk of IQ measurement relativity and possible score discrepancy could be taken into account. Of the 267 children included, 180 (67%) were identified through an institute that decides upon special education and allowances (MDPH) and 87 (33%) through the educational system. The parents of 181 children (68%) accepted to answer a telephone questionnaire, describing their child's educational and medical history. Children with MID frequently presented clinical signs and comorbidities. Educational trajectories were quite varied: a majority of the children (52.9%) were oriented toward sections with adapted general and professional education (SEGPA) after finishing primary school, a minority (41.3%) were oriented towards specialized schools, such as medical-educational institutions, and a small proportion of children (5.8%) stayed in ordinary school. Children followed the SEGPA orientation more frequently when a relative written language disorder was present, and autism-spectrum disorders or other clinical signs were absent. Concerning follow-up care and rehabilitation, children mostly took part in speech therapy (76.2%) and psychotherapy (55.8%). The French law dating from 2005, ensuring equal opportunity for people with disabilities, has borne fruit in the diversification of educational trajectories.


Subject(s)
Education of Intellectually Disabled , Intellectual Disability , Adolescent , Child , Female , France , Humans , Intellectual Disability/therapy , Male , Severity of Illness Index
20.
Phys Rev Lett ; 114(3): 036402, 2015 Jan 23.
Article in English | MEDLINE | ID: mdl-25659010

ABSTRACT

We report an experimental study of superfluid hydrodynamic effects in a one-dimensional polariton fluid flowing along a laterally patterned semiconductor microcavity and hitting a micron-sized engineered defect. At high excitation power, superfluid propagation effects are observed in the polariton dynamics; in particular, a sharp acoustic horizon is formed at the defect position, separating regions of sub- and supersonic flow. Our experimental findings are quantitatively reproduced by theoretical calculations based on a generalized Gross-Pitaevskii equation. Promising perspectives to observe Hawking radiation via photon correlation measurements are illustrated.

SELECTION OF CITATIONS
SEARCH DETAIL
...