Compressive three-dimensional super-resolution microscopy with speckle-saturated fluorescence excitation.

Nonlinear structured illumination microscopy (nSIM) is an effective approach for super-resolution wide-field fluorescence microscopy with a theoretically unlimited resolution. In nSIM, carefully designed, highly-contrasted illumination patterns are combined with the saturation of an optical transition to enable sub-diffraction imaging. While the technique proved useful for two-dimensional imaging, extending it to three-dimensions is challenging due to the fading of organic fluorophores under intense cycling conditions. Here, we present a compressed sensing approach that allows 3D sub-diffraction nSIM of cultured cells by saturating fluorescence excitation. Exploiting the natural orthogonality of speckles at different axial planes, 3D probing of the sample is achieved by a single two-dimensional scan. Fluorescence contrast under saturated excitation is ensured by the inherent high density of intensity minima associated with optical vortices in polarized speckle patterns. Compressed speckle microscopy is thus a simple approach that enables 3D super-resolved nSIM imaging with potentially considerably reduced acquisition time and photobleaching.

Recovery of deambulation after cardiothoracic surgery: a single center experience.

BACKGROUND: Surgical procedure and postoperative bed rest lead to musculoskeletal system alterations with a possibility of new walking dependence of patients who undergo cardiothoracic surgery, which is sometimes associated with prolonged hospitalization and increased health expenditure. AIM: The aim of this study was to assess the postoperative motor disability in inpatients admitted to the cardiothoracic surgical ward, and the results of customized rehabilitation in terms of recovery of postural changes and walking capacity with respect to the preoperative condition and destination after discharge. DESIGN: A prospective observational study was conducted. SETTING AND POPULATION: Four hundred seventeen inpatients, who had undergone cardiothoracic surgery, were enrolled between March 2011 and January 2012 in a Hospital Unit of Cardiothoracic Surgery. METHODS: A computerized system was used to collect data about ambulation at home, type and number of rehabilitation sessions proposed, ambulation at discharge, destination after discharge from ward of origin. All patients, who give their consent, undergone rehabilitative treatment on the ward of origin with an expert physiotherapist. RESULTS: Three hundred seventy-five inpatients were examined in Cardiac Surgery. One patient (0.26%) refused rehabilitative treatment. Two patients (0.53%) died. At the time of discharge 236 (74.45%) patients had recovered the ability to walk independently. After discharge 87.64% of patients was transferred to a specialist ward for intensive rehabilitation. Forty-two inpatients were enrolled in thoracic surgery. Two patients died whilst in hospital. At the time of discharge, 36 patients (94.73%) were able to walk independently. After discharge 80% of patients returned home. CONCLUSION: In our study, the application of an early and simple rehabilitation program on the ward of origin after surgery has made possible the recovery of ambulation of most inpatients who referred independence at home in a few days, limiting hospitalization and health expenditure. CLINICAL REHABILITATION IMPACT: Data about recovery of ambulation with respect to the preoperative condition and destination after discharge resume the importance of identifying motor impairment after surgery, in order to apply an adequate, early and feasible rehabilitation protocol to inpatients, limiting hospitalization and health expenditure.

When can temporally focused excitation be axially shifted by dispersion?

Temporal focusing (TF) allows for axially confined wide-field multi-photon excitation at the temporal focal plane. For temporally focused Gaussian beams, it was shown both theoretically and experimentally that the temporal focus plane can be shifted by applying a quadratic spectral phase to the incident beam. However, the case for more complex wave-fronts is quite different. Here we study the temporal focus plane shift (TFS) for a broader class of excitation profiles, with particular emphasis on the case of temporally focused computer generated holography (CGH) which allows for generation of arbitrary, yet speckled, 2D patterns. We present an analytical, numerical and experimental study of this phenomenon. The TFS is found to depend mainly on the autocorrelation of the CGH pattern in the direction of the beam dispersion after the grating in the TF setup. This provides a pathway for 3D control of multi-photon excitation patterns.

Near-field short range correlation in optical waves transmitted through random media.

Two-dimensional near-field images of light transmitted through a disordered dielectric structure have been measured for two probe wavelengths. From these data, the 2D spatial dependence of the intensity correlation function, C(deltaR-->), has been extracted. We observe that the spatial dependence of C is dominated by a rapidly varying feature determined by the wavelength of the probe light and the average refractive index of the material, as expected by theory. Finally, we deduce the absolute value of the effective refractive index by fitting the theoretical spatial dependence of C to our experimental results.

Near-field measurement of short-range correlation in optical waves transmitted through random media.

Two-dimensional near-field images of speckle patterns formed by optical waves transmitted through a disordered porous silica glass sample are measured. The corresponding 2D intensity correlation function, C, is extracted. The subwavelength spatial resolution of near-field microscopy allows us to resolve in the spatial distribution of C the expected subwavelength oscillations and to follow their dependence on the excitation wavelength. Finally, we deduce the effective refractive index of the material by fitting the theoretical spatial dependence of C to our experimental results.

Quantum mechanical repulsion of exciton levels in a disordered quantum well.

Spatially resolved photoluminescence spectra of a single quantum well are recorded by near-field spectroscopy. A set of over four hundred spectra displaying sharp emission lines from localized excitons is subject to a statistical analysis of the two-energy autocorrelation function. An accurate comparison with a quantum theory of the exciton center-of-mass motion in a two-dimensional spatially correlated disordered potential reveals clear signatures of quantum mechanical energy level repulsion, giving the spatial and energetic correlations of excitons in disordered quantum systems.

Low temperature near-field luminescence studies of localized and delocalized excitons in quantum wires.

Excitons in a GaAs quantum wire were studied in high-resolution photoluminescence experiments performed at a temperature of about 10 K with a spatial resolution of 160 nm and a spectral resolution of 100 microeV. We report the observation of quasi-one-dimensional excitons which are delocalized over a length of up to several micrometres along the quantum wire. Such excitons give rise to a 10 meV broad luminescence band, representing a superposition of transitions between different delocalized states. In addition, we find a set of sharp luminescence peaks from excitons localized on a sub150 nm length scale. Theoretical calculations of exciton states in a disordered quasi-one-dimensional potential reproduce the experimental results.

Femtosecond near-field spectroscopy: carrier relaxation and transport in single quantum wires.

Quasi-two-colour femtosecond pump and probe spectroscopy and near-field scanning optical microscopy are combined to study the carrier dynamics in single semiconductor nanostructures. In temporally, spectrally and spatially resolved measurements with a time resolution of 200 fs and a spatial resolution of 200 nm, the non-linear change in reflectivity of a single quantum wire is mapped in real space and time. The experiments show that carrier relaxation into a single quantum wire occurs on a 100 fs time scale at room temperature. Evidence is given for a transient unipolar electron transport along the wire axis on a picosecond time and 100 nm length scale.

Formation of supernumerary euchromatic short arm isochromosomes: parent and cell stage of origin in new cases and review of the literature.

In order to get insight in the formation of isochromosomes we analysed different supernumerary euchromatic short arm isochromosomes for the parent and cell stage of origin. After cytogenetic detection and confirmation by fluorescence-in-situ hybridization we performed short tandem repeat typing in a child with i(9p), three with i(12p) and three with i(18p). The extra chromosomes were monocentric in each case, the i(9p) and i(12p) constitutions were found in mosaic with normal cell lines. Our results and those of other groups indicate a strong role of maternal meiosis in isochromosome formation: in one i(8p), 4 out of 5 i(9p), 7 out of 12 i(12p) and 18 out of 23 i(18p) families a maternal meiotic nondisjunction had occurred prior to the centromere misdivision. For chromosome 18, the majority of isochromosomes originated from a maternal meiosis II error (16/18). For the other tetrasomic constitutions the isochromosomes could be delineated from paternal as well as from maternal origin, the short tandem repeat typing patterns being consistent with meiotic or mitotic cell stages of formation. Thus, independently of the chromosomal origin, in the majority of cases with additional euchromatic isochromosomes maternal meiosis nondisjunction is the initial step followed by centromeric misdivision. Postzygotic nondisjunction as suggested previously due to mosaics observed in tetrasomies 9p and 12p seems to be of minor importance. The observed origin of isochromosomes 18 corresponds to that of trisomy 18, where the majority of cases can be delineated from maternal meiosis II errors.

Streptococcus bovis brain abscess associated with an occult colonic villous adenoma.

Streptococcus bovis is now recognized as a common cause of bacterial endocarditis. However, infection of the central nervous system by this organism is very rare. Recent studies have demonstrated the association between Streptococcus bovis infections and colonic neoplasms.

Dilated cardiomyopathy associated with chylous ascites.

Chylous ascites is a well-documented sequelae of traumatic rupture of the thoracic duct and mechanical obstruction of the lymphatic system due to neoplastic, inflammatory, or congenital anomalies. Less commonly, chylous ascites results from altered hemodynamics and lymphatic flow, as seen in cirrhosis and constrictive pericarditis. Rarely, severe right-sided heart failure from a variety of causes has also resulted in chylous ascites or a protein-losing enteropathy. We report a case of chylous ascites due to dilated cardiomyopathy with autopsy findings. The pathophysiology of chylous ascites formation in right heart failure will be discussed, with a review of the literature.