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Non-linear excitation microscopy offers several advantages for in-vivo imaging compared to conventional confocal techniques. However, tissue penetration can still be an issue due to scattering and spherical aberrations induced on focused beams by the tissue. The use of low numerical aperture objectives to pass through the outer layers of the skin, together with high dioptric power microlenses implanted in-vivo close to the observation volume, can be beneficial to the reduction of optical aberrations. Here, we develop and test on fibroblast cell culture plano-convex microlenses to be used for non-linear imaging of biological tissue. The microlenses can be used as single lenses or multiplexed in an array. A thorough test of the lenses wavefront is reported together with the modulation transfer function and wavefront profile. We could retrieve magnified fluorescence images through the microlenses coupled to commercial confocal and two-photon excitation scanning microscopes. The signal-to-noise ratio of the images is not substantially affected by the use of the microlenses and the magnification can be adjusted by changing the relative position of the microlens array to the microscope objective and the immersion medium. These results are opening the way to the application of implanted micro-optics for optical in-vivo inspection of biological processes.

Raman microscopy is a powerful analytical technique for materials and life sciences that enables mapping the spatial distribution of the chemical composition of a sample. State-of-the-art Raman microscopes, based on point-scanning frequency-domain detection, have long (∼1s) pixel dwell times, making it challenging to acquire images of a significant area (e.g., 100×100µm). Here we present a compact wide-field Raman microscope based on a time-domain Fourier-transform approach, which enables parallel acquisition of the Raman spectra on all pixels of a 2D detector. A common-path birefringent interferometer with exceptional delay stability and reproducibility can rapidly acquire Raman maps (∼30min for a 250000pixel image) with high spatial (−1) resolutions. Time-domain detection allows us to disentangle fluorescence and Raman signals, which can both be measured separately. We validate the system by Raman imaging plastic microbeads and demonstrate its multimodal operation by capturing fluorescence and Raman maps of a multilayer-WSe2 sample, providing complementary information on the strain and number of layers of the material.

Monolayer transition metal dichalcogenides bear great potential for photodetection and light harvesting due to high absorption coefficients. However, these applications require dissociation of strongly bound photogenerated excitons. The dissociation can be achieved by vertically stacking different monolayers to realize band alignment that favors interlayer charge transfer. In such heterostructures, the reported recombination times vary strongly, and the charge separation and recombination mechanisms remain elusive. We use two color pump-probe microscopy to demonstrate that the charge separation in a MoSe2/WSe2 heterostructure is ultrafast (∼200 fs) and virtually temperature independent, whereas the recombination accelerates strongly with temperature. Ab initio quantum dynamics simulations rationalize the experiments, indicating that the charge separation is temperature-independent because it is barrierless, involves dense acceptor states, and is promoted by higher-frequency out-of-plane vibrations. The strong temperature dependence of the recombination, on the other hand, arises from a transient indirect-to-direct bandgap modulation by low-frequency shear and layer breathing motions.

We demonstrate quantum control of ^{9}Be^{+} ions directly implemented by an optical frequency comb. Based on numerical simulations of the relevant processes in ^{9}Be^{+} for different magnetic field regimes, we demonstrate a wide applicability when controlling the comb's spectral properties. We introduce a novel technique for the selective and efficient generation of a spectrally tailored narrow-bandwidth optical frequency comb near 313 nm. We experimentally demonstrate internal state control and internal-motional state coupling of ^{9}Be^{+} ions implemented by stimulated-Raman manipulation using a spectrally optimized optical frequency comb. Our pulsed laser approach is a key enabling step for the implementation of quantum logic and quantum information experiments in Penning traps.

The three-dimensional topological insulator Bi

Van der Waals heterostructures have emerged as promising building blocks that offer access to new physics, novel device functionalities and superior electrical and optoelectronic properties 1-7 . Applications such as thermal management, photodetection, light emission, data communication, high-speed electronics and light harvesting 8-16 require a thorough understanding of (nanoscale) heat flow. Here, using time-resolved photocurrent measurements, we identify an efficient out-of-plane energy transfer channel, where charge carriers in graphene couple to hyperbolic phonon polaritons 17-19 in the encapsulating layered material. This hyperbolic cooling is particularly efficient, giving picosecond cooling times for hexagonal BN, where the high-momentum hyperbolic phonon polaritons enable efficient near-field energy transfer. We study this heat transfer mechanism using distinct control knobs to vary carrier density and lattice temperature, and find excellent agreement with theory without any adjustable parameters. These insights may lead to the ability to control heat flow in van der Waals heterostructures.

Aim Selected patients with haemorrhoidal prolapse undergoing double stapled anopexy with the procedure for prolapse and haemorrhoids (PPH03) were studied. Method Between March 2007 and March 2010, 235 patients referred with haemorrhoids were included in the study. Patients with obstructed defaecation were excluded. At surgery intraoperative evaluation for double stapled anopexy was carried out based on the criteria of prolapse occupying half or more of the anal circumference and redundant prolapsed tissue determined by the circular anal dilator. Patients fulfilling these criteria were submitted for double stapled anopexy with the PPH03 stapler. All clinical and operative data were recorded in a prospectively maintained database. Results Among the 142 patients with haemorrhoidal prolapse having surgery 91 had a single and 51 a double stapled technique. The mean operative time was 34.8 min with no major or minor intraoperative complications. Recurrence at 48 months was 1.9% and the mean satisfaction score was 8.9. Conclusion The double stapled PPH03 technique in selected cases was as safe and effective as a single stapling technique with a lower incidence of recurrence over a medium-term follow-up.

Frequency shifts of optical pulses can be achieved exploiting propagation in nonlinear crystals. Spectral blue-shifts and red-shifts, originating from a phase-mismatched second harmonic generation process under conditions of strong group-velocity mismatch, can be efficiently controlled by acting on pulse intensity and phase-mismatch. We show theoretically and experimentally that spectral blue-shifts and spectral red-shifts in a range of 100 nm are achieved by propagating 40 fs pulses with a 70 nm spectrum centered at 1450 nm in a 25-mm-long periodically poled stoichiometric lithium tantalate crystal. This crystal can be exploited for the realization of a single-pass device that tunes the carrier frequency output from a femtosecond fiber laser with continuity and over a broad range.

First described by A. Trillat, the double patella is an uncommon clinical feature following repetitive injuries of the extensor mechanism of the knee. The first injury is a tendo-periosteal avulsion of the suprapatellar or, less frequently, infrapatellar tendon from the corresponding patellar pole. Often these avulsions are misdiagnosed and therefore treated only with a cast or no immobilization at all. Subsequent giving-way episodes lead to extensive ossification which is adjacent to or separated from the patella. The peculiar shape of this ossification overriding or underlying the primary kneecap justifies the denomination of double patella. Surgical treatment consists of removal of the calcification and reattachment of the tendon to the patella by transosseous sutures.

Selected patients with haemorrhoidal prolapse undergoing double stapled anopexy with the procedure for prolapse and haemorrhoids (PPH03) were studied.Between March 2007 and March 2010, 235 patients referred with haemorrhoids were included in the study. Patients with obstructed defaecation were excluded. At surgery intraoperative evaluation for double stapled anopexy was carried out based on the criteria of prolapse occupying half or more of the anal circumference and redundant prolapsed tissue determined by the circular anal dilator. Patients fulfilling these criteria were submitted for double stapled anopexy with the PPH03 stapler. All clinical and operative data were recorded in a prospectively maintained database.Among the 142 patients with haemorrhoidal prolapse having surgery 91 had a single and 51 a double stapled technique. The mean operative time was 34.8 min with no major or minor intraoperative complications. Recurrence at 48 months was 1.9% and the mean satisfaction score was 8.9.The double stapled PPH03 technique in selected cases was as safe and effective as a single stapling technique with a lower incidence of recurrence over a medium-term follow-up.

This chapter will study the effectiveness of discreet, secure, hands-free, wireless communications methods for enhancing coordination during security incidents among cabin crewmembers, between the cabin and flight compartment, ground support personnel. It will identify breakthrough technologies to mitigate the likelihood of individual radical and/or violent behavior, resulting in catastrophic airline casualties, to improve communications and overall safety in-flight.

Sorting and sizing of DNA molecules within the human genome project has enabled the genetic mapping of various illnesses. Furthermore by employing tiny lab-on-a-chip device, integrated DNA sequencing and genetic diagnostics have become feasible. We present the combination of capillary electrophoresis with laser-induced fluorescence for optofluidic integration toward an on-chip bio-analysis tool. Integrated optical fluorescence excitation allows for a high spatial resolution (12 μm) in the electrophoretic separation channel, and can lead to a further 20-fold enhancement as soon as improved microfluidic protocols become available. We demonstrate accurate sizing (with > 99% sizing accuracy) and highly sensitive (LOD = 220 femtomolar, corresponding to merely 6 molecules in the excitation volume) fluorescence detection of double-stranded DNA molecules by integrated waveguide laser excitation. Subsequently, we introduced a principle of parallel optical processing to this optofluidic lab on a chip. In this approach, different sets of exclusively color-labeled DNA fragments - otherwise rendered indistinguishable by their spatial (in the microchip CE separation channel) and temporal (in the consequent electropherogram) coincidence - are traced back to their origin by modulation-frequency-encoded multi-wavelength laser excitation, fluorescence detection with a color-blind photomultiplier, and Fourier-analytical decoding. As a proof of principle, fragments obtained by multiplex ligation-dependent probe amplification from independent human genomic segments, associated with genetic predispositions to breast cancer and anemia, are simultaneously analyzed. The techniques described in this thesis for multiple, yet unambiguous optical identification of biomolecules will potentially open new horizons for “enlightened‿ lab-on-a-chip devices in the future.

The objective of this study was to evaluate the mid-term results of a new technique for the arthroscopic repair of MPFL after an acute patellar dislocation (APD).The series included 17 patients (11 men and 6 women) with a first episode of acute patellar dislocation; treated over a period of 6 years. Re-dislocation, subjective symptoms and functional limitations were evaluated at an average follow-up of 2.2 years (1-5.5). The patients were evaluated with the Lysholm and the Kujala scoring systems.At follow-up, no re-dislocation was reported. Only one patient referred an episode of patellar instability, without a distinct dislocation. The postoperative median Lysholm score was 90 (72-100). The median Kujala score was 92 (75-100). Fourteen out of 17 patients were able to return to sports at the same level as before.When the MPFL is avulsed from the patella, the proposed technique has the advantage of restoring tension of the ligament through reattachment at the patellar border with two trans-patellar sutures. The full-arthroscopic approach has the advantage of being less invasive and having a shorter recovery time.

Osteoarthrosis of the valgus knee has many causative factors. Degenerative changes of the articular cartilage can occur through tension, compression or shear. They are highly related to the forces exerted on the bearing surfaces. The overload caused by congenital valgus deformity or secondary to articular or metaphyseal fractures and lateral meniscectomy are aetiologically important. In essence biophysical cause for osteoarthrosis is an overload or a concentration of forces beyond the ability of the cartilage and subchondral bone to cope.

We generate 8.5 fs pulses at 1.6 mm from an 800-nm-pumped optical parametric amplifier working at degeneracy, employing a deformable mirror compressor. These are the shortest light pulses in this wavelength range.

We generate ultrabroadband pulses, spanning the 1200-2100 nm wavelength range, from an 800 nm pumped optical parametric amplifier (OPA) working at degeneracy. We compress the microjoule-level energy pulses to nearly transform-limited 8.5 fs duration by an adaptive system employing a deformable mirror. To our knowledge, these are the shortest light pulses generated at 1.6 mu m. (C) 2008 Optical Society of America.