Coupling of light and mechanics in a photonic crystal waveguide.

Observations of thermally driven transverse vibration of a photonic crystal waveguide (PCW) are reported. The PCW consists of two parallel nanobeams whose width is modulated symmetrically with a spatial period of 370 nm about a 240-nm vacuum gap between the beams. The resulting dielectric structure has a band gap (i.e., a photonic crystal stop band) with band edges in the near infrared that provide a regime for transduction of nanobeam motion to phase and amplitude modulation of an optical guided mode. This regime is in contrast to more conventional optomechanical coupling by way of moving end mirrors in resonant optical cavities. Models are developed and validated for this optomechanical mechanism in a PCW for probe frequencies far from and near to the dielectric band edge (i.e., stop band edge). The large optomechanical coupling strength predicted should make possible measurements with an imprecision below that at the standard quantum limit and well into the backaction-dominated regime. Since our PCW has been designed for near-field atom trapping, this research provides a foundation for evaluating possible deleterious effects of thermal motion on optical atomic traps near the surfaces of PCWs. Longer-term goals are to achieve strong atom-mediated links between individual phonons of vibration and single photons propagating in the guided modes (GMs) of the PCW, thereby enabling optomechanics at the quantum level with atoms, photons, and phonons. The experiments and models reported here provide a basis for assessing such goals.

Reduced volume and reflection for bright optical tweezers with radial Laguerre-Gauss beams.

Spatially structured light has opened a wide range of opportunities for enhanced imaging as well as optical manipulation and particle confinement. Here, we show that phase-coherent illumination with superpositions of radial Laguerre-Gauss (LG) beams provides improved localization for bright optical tweezer traps, with narrowed radial and axial intensity distributions. Further, the Gouy phase shifts for sums of tightly focused radial LG fields can be exploited for phase-contrast strategies at the wavelength scale. One example developed here is the suppression of interference fringes from reflection near nanodielectric surfaces, with the promise of improved cold-atom delivery and manipulation.

Coherent Backscattering of Light Off One-Dimensional Atomic Strings.

We present the first experimental realization of coherent Bragg scattering off a one-dimensional system-two strings of atoms strongly coupled to a single photonic mode-realized by trapping atoms in the evanescent field of a tapered optical fiber, which also guides the probe light. We report nearly 12% power reflection from strings containing only about 1000 cesium atoms, an enhancement of 2 orders of magnitude compared to reflection from randomly positioned atoms. This result paves the road towards collective strong coupling in 1D atom-photon systems. Our approach also allows for a straightforward fiber connection between several distant 1D atomic crystals.

Generation and detection of a sub-Poissonian atom number distribution in a one-dimensional optical lattice.

We demonstrate preparation and detection of an atom number distribution in a one-dimensional atomic lattice with the variance -14 dB below the Poissonian noise level. A mesoscopic ensemble containing a few thousand atoms is trapped in the evanescent field of a nanofiber. The atom number is measured through dual-color homodyne interferometry with a pW-power shot noise limited probe. Strong coupling of the evanescent probe guided by the nanofiber allows for a real-time measurement with a precision of ±8 atoms on an ensemble of some 10(3) atoms in a one-dimensional trap. The method is very well suited for generating collective atomic entangled or spin-squeezed states via a quantum nondemolition measurement as well as for tomography of exotic atomic states in a one-dimensional lattice.

Outcome of dogs and cats with benign oesophageal strictures after balloon dilatation or stenting: 27 cases (2002-2019).

OBJECTIVES: Acquired oesophageal strictures remain challenging to manage in canine and feline patients. The aims of this study were to describe the treatment, complications, short-term outcome and long-term follow-up of benign oesophageal strictures treated by balloon dilatation or stenting in dogs and cats and to describe adjunctive techniques to minimise the complication rate of stent placement. MATERIALS AND METHODS: Retrospective analysis of medical records of dogs and cats with benign oesophageal stricture diagnosed under endoscopy between 2002 and 2019. RESULTS: Eighteen dogs and nine cats were included, representing 39 strictures. Balloon dilatation was used as first-line therapy, with a good outcome in 59% of cases. Stents were placed in eight cases due to stricture recurrence; 88% had a long-term satisfactory outcome. Short-term complications occurred in six of eight cases; migration and aberrant mucosal reaction were uncommon. In three cases, progressive mesh cutting during follow-up reduced discomfort and trichobezoars formation and improved long-term stent tolerance. Overall median survival time was 730 days. CLINICAL SIGNIFICANCE: Long-term prognosis of balloon dilatation as a first-line therapy for esophageal strictures and of stenting as a rescue therapy was considered satisfactory. Although discomfort associated with stenting was frequent, tolerability might be improved by per-endoscopic adjunctive techniques.

[Long-term follow-up of a multimodally managed pulmonary mucoepidermoid carcinoma in a cat]. / Langzeitstudie einer multimodalen Behandlung eines mukoepidermoiden Lungenkarzinoms bei einer Katze.

INTRODUCTION: The present case describes the treatment of a mucoepidermoid carcinoma in a 13-year-old female sterilized European domestic cat, using lung lobectomy and -accompanying mitoxantrone chemotherapy. Six, 14, 19 and 27 months after the initial treatment tomodensitometric and radiographic examinations showed no abnormalities. However, the cat had to be euthanized 27 months after the lung lobectomy due to a soft tissue sarcoma in the interscapular area.

INTRODUCTION: Ce cas décrit un carcinome mucoépidermoïde chez un chat européen femelle stérilisée de 13 ans, entité non rapportée jusqu'alors chez cette espèce, pris en charge par lobectomie pulmonaire et chimiothérapie adjuvante avec de la mitoxantrone. L'examen tomodensitométrique et les clichés radiographiques, réalisés respectivement 6 mois, 14, 19 mois, et 27 mois après la chirurgie, ne mettaient en évidence aucune anomalie. Cependant, vingt-sept mois après l'intervention chirurgicale, une euthanasie est réalisée suite à l'aggravation en quelques mois d'un sarcome des tissus mous en région inter-scapulaire.

Primary hypoaldosteronism in a dog with pituitary and adrenal T-cell lymphoma.

A 7-year-old mixed breed dog was presented with a 2-week history of vomiting, diarrhoea, weakness and loss of appetite. Initial laboratory tests revealed hyponatraemia and hyperkalaemia consistent with hypoadrenocorticism. Basal plasma cortisol and adrenocorticotropic hormone concentrations were not suggestive of primary hypoadrenocorticism but the aldosterone concentration was undetectable. Abdominal ultrasound scan showed a mass within the left kidney and a nodular enlargement of the left adrenal gland. Cytological analysis revealed a large granular lymphoma. The dog died 17 days later. Post mortem histological and immunohistochemical examinations revealed a diffuse large granular T-cell lymphoma involving the mediastinal lymph node, kidneys, pancreas, adrenal and pituitary glands.

Prilocaine in arthroscopy: clinical pharmacokinetics and rational use.

Prilocaine pharmacokinetics were determined in 60 patients receiving the drug by two different routes of administration (intra-articular and subcutaneous) during arthroscopy under local anesthesia with controlled pressure irrigation. Resorption of prilocaine by subcutaneous tissues was slow and did not lead to high serum levels. On the contrary, prilocaine resorption by the synovium was fast and induced a sharp serum peak (265.8 +/- 163.5 ng/ml) in the hour after the end of the examination. The drug was completely eliminated from the blood after 24 hours, as the prilocaine t1/2 is about 5 hours. The first procedure was perfected to reduce the risk of methemoglobinemia, which occurred in four of 105 patients. Applied pressure was lowered to 100 mm Hg to prevent the escape of anesthetic solution into the soft tissue of the leg, the prilocaine concentration was reduced to 1 gm/L, and the arthroscope was only set up after a delay to allow the intra-articular anesthetic effect of prilocaine to become established. So far, 200 arthroscopies have been performed with this improved protocol without any problem.

[The value of electromagnetic waves in delayed union. Apropos of 21 cases]. / Intérêt des ondes électromagnétiques dans les retards de consolidation. A propos de 21 cas.

Healing was obtained in 21 fractures with delayed union or pseudarthrosis by stimulation of the bone with electromagnetic waves. The interest of this method lies in a number of factors: the apparatus Centicure is miniaturized and very easy to handle; the daily treatment is performed by the patient himself; and application may be split, allowing normal and even professional activity. The method requires no immobilization nor surgical electrode implantation, the cost of the treatment is low and the apparatus can be used for several patients. Bone healing was seen in 15 cases of the 19 reviewed after a brief treatment period. Stimulation by means of magnetic fields, on the other hand, has obvious drawbacks, including high costs.

[Considerations concerning the treatment of pseudarthrosis of the humerus]. / Considérations à propos du traitement des pseudarthroses de l'humérus.

A humeral shaft fracture results in a nonunion in less than 10% of cases, regardless of the technique used. The treatment of such cases must be different from the initial treatment. In a pseudarthrosis of the medial shaft of the humerus with a transverse or short oblique line, a suitable procedure is medullary filling with Hackethal nails or a Küntscher nail. If the fracture line is long and oblique, spiral, fragmented or distant from the narrow part of the humeral shaft, a modified interlocking intramedullary nail is recommended.

[Lateral meniscal cyst. Retrospective study of 105 cysts treated with arthroscopy with 5 year follow-up]. / Les kystes du ménisque latéral. Etude rétrospective de 105 kystes traités par arthroscopie avec 5 ans de recul.

UNLABELLED: A retrospective study was performed on 122 patients with 124 lateral meniscal cysts, selected from a series of 8100 knee arthroscopies (1.5 per cent). Eight of the patients were lost for follow up, 11 patients had chronic anterior cruciate ligament deficiency or previous medial meniscectomy. Therefore 105 of 124 patients were included in this study. Average follow-up was 5 years (range of 1 to 12.5 years). MATERIAL AND METHODS: Mean age was 33 years (range of 12 to 69 years). All patients had pain over the joint line with a palpable mass. All were noted to have a meniscal tear at the time of surgery and 60 (57 per cent) had a horizontal cleavage component. They were all arthroscopically treated. RESULTS: Meniscal tears were treated by arthroscopic partial meniscectomy in 104 cases and meniscal repair in one case. Cysts were treated by intra-articular debridement in 91 cases and open cystremoval in 14 cases. Eleven cysts recurred and a second arthroscopy was required. The clinical results, including cysts recurrence, were excellent or good in 87 per cent of cases. Osteoarthritis following treatment of these meniscal cysts occurred in 9 per cent of cases. CONCLUSION: When there is a cyst and no other intra-articular damage, the prognosis was excellent at 5 year follow-up. For lateral meniscal cysts; arthroscopic partial meniscectomy with intra-articular debridement yields predictable results.

[Villonodular synovitis of the knee. Analysis of a series of 17 cases and review of the literature]. / La synovite villonodulaire du genou. Analyse d'une série de 17 cas et revue de la littérature.

PURPOSE OF THE STUDY: Pigmented villonodular synovitis is a rare pathology found predominantly in the knee. We report management and treatment of 17 cases of pigmented villonodular synovitis of the knee. MATERIAL AND METHODS: The mean follow-up was 9 years (maximum: 17 years). The diagnosis was always confirmed at histopathology. There were 12 women and 5 men. The average age at the initial symptoms was 28 years. Six cases were diffuse, 7 localized and 4 cases were mixed. RESULTS: First treatment was only arthroscopic in 8 cases, and open synovectomy in 6 cases and mixed in 2 cases. Six patients had a recurrence, one had more than one recurrence. The mean delay for recurrence was 2 years and 5 months. Loss of range of motion was noted in 6 cases. For these 6 cases, flexion was always greater than 90 degrees and flessum always inferior to 10 degrees. DISCUSSION: Ethiopathogeny of this disease is unclear and no etiopathogenic theory is defined. Magnetic resonance imaging is useful for diagnosis, and absolutely necessary for preoperative tumor localization, and also for survey. In localized types, arthroscopic synovectomy can be performed with success but in diffuse or mixed form an open synovectomy must be performed according to the high rate or recurrence observed after incomplete synovectomy. Synoviorthesis with Yttrium 90 seems to be a good adjuvant for the treatment of recurrent pigmented villonodular synovitis. CONCLUSION: Arthroscopy is the treatment of choice for localized forms. We propose a mixed concept with an anterior and parameniscal arthroscopic synovectomy (without meniscectomy), an open synovectomy for the posterior localization, and an open anterior synovectomy when the tumor mass is too voluminous.

[Study of femoro-tibial cartilage diseases with MRI]. / Exploration des chondropathies fémoro-tibiales en IRM.

Magnetic resonance imaging provides excellent tissue contrast resolution and can therefore be used to visualize joint cartilage. The goal of this study was to evaluate the value of magnetic resonance imaging for the diagnosis of femorotibial cartilage lesions. Spin-echo magnetic resonance imaging was performed in 37 patients. As compared with arthroscopy, the accuracy, sensitivity, and specificity of magnetic resonance imaging were 72.5%, 47%, and 95.5%, respectively. Only advanced cartilage lesions with exposure of subchondral bone were clearly seen on magnetic resonance sections. Limiting factors included insufficient spatial resolution and the chemical shift phenomenon. Spin-echo sequences used in everyday practice are not appropriate for detecting small cartilage lesions. Controlled studies are needed to determine whether gradient echo sequences are more satisfactory.