Faecal Calprotectin and a Twenty-Four-Parameter Questionnaire in Autistic Children with Gastrointestinal Symptoms

This study investigated potential correlation between the inflammatory marker, Calprotectin, and a S.O.S questionnaire from forty-nine Autistic children. Symptom and behavioral questionnaires were completed contemporaneously with stool sample collection. Mixed Model data analysis showed strong correlation between some questionnaire parameters and Calprotectin. ‘Need for a fixed routine’ was highly significantly correlated with Calprotectin (\u1d45d<0.00009) with Multivariate Coefficient of 3.227, whilst paradoxically ‘constipation’ indicated significant change (\u1d45d<0.02) with negative Multivariate Coefficient (-1.584). The negative ‘constipation’ appears to associate with the positive ‘need for a fixed routine’ indicating possibility of reciprocal, independent prediction of gastrointestinal inflammation. Results suggest that ‘need for a fixed routine’ and ‘constipation’ be included in a screening questionnaire as independent predictors of bowel dysfunction in these children

Effectiveness of visceral osteopathic treatment on gastrointestinal indicators and behaviour patterns in autistic children: using questionnaire and biochemical markers to measure outcomes

Introduction. The precise aetiology of autism is unclear, however recent studies link autism with gastrointestinal (GI) dysfunction. Although there is no specific treatment, the potential to ameliorate the behavioural and GI problems of autistic children is of interest. This study aimed to evaluate inflammatory markers in faecal samples taken from autistic children with GI dysfunction before, during and after visceral osteopathic techniques (VOT), and to link these findings with contemporaneous questionnaires. These data assessed whether GI status could be reliably determined from a single sample, whether VOT affected behaviour and clinical signs, and whether there was any association between biochemical markers and the questionnaire. Methods. Faecal samples were analysed for three biochemical markers, calprotectin, M2-pyruvate kinase and lactoferrin. Forty nine children, between 3½ and 8 years old, and independently diagnosed as autistic by specialist professionals were recruited. Questionnaires using a 10 point Likert scale assessed behavioural parameters and clinical signs throughout the 18 week study period, before, during and after VOT. Results. Due to intra-individual biological variability, analysis of single faecal samples over time did not give a consistent readout of marker levels. The questionnaire showed significant improvement in symptoms and behaviour during treatment, specifically, reduction in vomiting (p<0.001), and poor appetite (p<0.05), and an increase in eye contact (p<0.05). Analysis of an inflammatory marker, together with the questionnaire, showed a highly significant association of ‘need for a fixed routine’ (p<0.0001) and ‘constipation’ (p<0.02) parameters with calprotectin, and showing multivariate coefficients of 3.227 and -1.584 respectively. Discussion and Conclusion. VOT ameliorates GI symptoms in these autistic children and a standardised questionnaire could include ‘need for a fixed routine’ and ‘constipation’ as independent predictors of their bowel dysfunction. This study uniquely used biochemical markers to assess symptomatic changes before, during and after VOT

Comment on "Linear wave dynamics explains observations attributed to dark-solitons in a polariton quantum fluid"

In a recent preprint (arXiv:1401.1128v1) Cilibrizzi and co-workers report experiments and simulations showing the scattering of polaritons against a localised obstacle in a semiconductor microcavity. The authors observe in the linear excitation regime the formation of density and phase patterns reminiscent of those expected in the non-linear regime from the nucleation of dark solitons. Based on this observation, they conclude that previous theoretical and experimental reports on dark solitons in a polariton system should be revised. Here we comment why the results from Cilibrizzi et al. take place in a very different regime than previous investigations on dark soliton nucleation and do not reproduce all the signatures of its rich nonlinear phenomenology. First of all, Cilibrizzi et al. consider a particular type of radial excitation that strongly determines the observed patterns, while in previous reports the excitation has a plane-wave profile. Most importantly, the nonlinear relation between phase jump, soliton width and fluid velocity, and the existence of a critical velocity with the time-dependent formation of vortex-antivortex pairs are absent in the linear regime. In previous reports about dark soliton and half-dark soliton nucleation in a polariton fluid, the distinctive dark soliton physics is supported both by theory (analytical and numerical) and experiments (both continuous wave and pulsed excitation).Comment: 4 pages, 2 figure

All -optical control of the quantum flow of a polariton condensate

Although photons in vacuum are massless particles that do not appreciably interact with each other, significant interactions appear in suitable nonlinear media, leading to hydrodynamic behaviours typical of quantum fluids(1-6). Here, we show the generation and manipulation of vortex-antivortex pairs in a coherent gas of strongly dressed photons (polaritons) flowing against an artificial potential barrier created and controlled by a light beam in a semiconductor microcavity. The optical control of the polariton flow allows us to reveal new quantum hydrodynamical phenomenologies such as the formation of vortex pairs upstream from the optical barrier, a case of ultra-short time excitation of the quantum flow, and the generation of vortices with counterflow trajectories. Additionally, we demonstrate how to permanently trap and store quantum vortices hydrodynamically generated in the wake of a defect. These observations are supported by time-dependent simulations based on the non-equilibrium Gross-Pitaevskii equation(7)

Stable one-dimensional periodic waves in Kerr-type saturable and quadratic nonlinear media

We review the latest progress and properties of the families of bright and dark one-dimensional periodic waves propagating in saturable Kerr-type and quadratic nonlinear media. We show how saturation of the nonlinear response results in appearance of stability (instability) bands in focusing (defocusing) medium, which is in sharp contrast with the properties of periodic waves in Kerr media. One of the key results discovered is the stabilization of multicolor periodic waves in quadratic media. In particular, dark-type waves are shown to be metastable, while bright-type waves are completely stable in a broad range of energy flows and material parameters. This yields the first known example of completely stable periodic wave patterns propagating in conservative uniform media supporting bright solitons. Such results open the way to the experimental observation of the corresponding self-sustained periodic wave patterns.Comment: 29 pages, 10 figure

Polariton superfluids reveal quantum hydrodynamic solitons

A quantum fluid passing an obstacle behaves differently from a classical one. When the flow is slow enough, the quantum gas enters a superfluid regime and neither whirlpools nor waves form around the obstacle. For higher flow velocities, it has been predicted that the perturbation induced by the defect gives rise to the turbulent emission of quantised vortices and to the nucleation of solitons. Using an interacting Bose gas of exciton-polaritons in a semiconductor microcavity, we report the transition from superfluidity to the hydrodynamic formation of oblique dark solitons and vortex streets in the wake of a potential barrier. The direct observation of these topological excitations provides key information on the mechanisms of superflow and shows the potential of polariton condensates for quantum turbulence studies.Comment: Published version with corrected colorbar scale for Fig. 3. Raw data available as ancillary file

Stable multicolor periodic-wave arrays

We study the existence and stability of cnoidal periodic wave arrays propagating in uniform quadratic nonlinear media and discover that they become completely stable above a threshold light intensity. To the best of our knowledge, this is the first example in physics of completely stable periodic wave patterns propagating in conservative uniform media supporting bright solitons.Comment: 12 pages, 3 figure

Observation of Superfluidity of Polaritons in Semiconductor Microcavities

One of the most striking manifestations of quantum coherence in interacting boson systems is superfluidity. Exciton-polaritons in semiconductor microcavities are two-dimensional composite bosons predicted to behave as particular quantum fluids. We report the observation of superfluid motion of polaritons created by a laser in a semiconductor microcavity. Superfluidity is investigated in terms of the Landau criterion and manifests itself as the suppression of scattering from defects when the flow velocity is slower than the speed of sound in the fluid. On the other hand, a Cerenkov-like wake pattern is clearly observed when the flow velocity exceeds the speed of sound. The experimental findings are in excellent quantitative agreement with the predictions based on a generalized Gross-Pitaevskii theory, showing that polaritons in microcavities constitute a very rich system for exploring the physics of non-equilibrium quantum fluids.Comment: 14 pages, 3 figure