Integrated optics for astronomical interferometry. I. Concept and astronomical applications

We propose a new instrumental concept for long-baseline optical single-mode interferometry using integrated optics which were developed for telecommunication. Visible and infrared multi-aperture interferometry requires many optical functions (spatial filtering, beam combination, photometric calibration, polarization control) to detect astronomical signals at very high angular resolution. Since the 80's, integrated optics on planar substrate have become available for telecommunication applications with multiple optical functions like power dividing, coupling, multiplexing, etc. We present the concept of an optical / infrared interferometric instrument based on this new technology. The main advantage is to provide an interferometric combination unit on a single optical chip. Integrated optics are compact, provide stability, low sensitivity to external constrains like temperature, pressure or mechanical stresses, no optical alignment except for coupling, simplicity and intrinsic polarization control. The integrated optics devices are inexpensive compared to devices that have the same functionalities in bulk optics. We think integrated optics will fundamentally change single-mode interferometry. Integrated optics devices are in particular well-suited for interferometric combination of numerous beams to achieve aperture synthesis imaging or for space-based interferometers where stability and a minimum of optical alignments are wished.Comment: 11 pages, 8 figures, accpeted by Astronomy and Astrophysics Supplement Serie

PROPOSAL OF A PRESURGICAL ALGORITHM FOR PATIENTS AFFECTED BY OBSTRUCTIVE SLEEP APNEA SYNDROME

PURPOSE: To propose an algorithm for the preoperative management of patients with obstructive sleep apnea syndrome (OSAS) and review the surgical outcomes in such patients. MATERIALS AND METHODS: This prospective cohort study involved 71 patients with OSAS who underwent presurgical upper airway endoscopy and cephalometry before being assigned to treatment categories based on the site(s) of obstruction, the pattern of collapse, the characteristics of the soft tissue, the air space between the base of the tongue and the posterior wall of the pharynx, and the severity of OSAS. Six months after surgery, they were followed up using polysomnography and the Epworth Sleepiness Scale. The pre- and postsurgical data were compared using a paired Student t test. RESULTS: The mean preoperative apnea/hypopnea index of the 71 patients (61 male and 10 female) was 40.98 events/hour (range, 14.7 to 87.6 events/hr), and the mean postoperative apnea/hypopnea index was 13.96 events/hour (range, 0 to 20 events/hr). The difference was statistically significant (P < .001). CONCLUSIONS: This algorithm was developed on the principle that every patient with OSAS should be considered individually. In the authors' opinion, taking into account the number, site(s), pattern, and degree of the collapse/obstruction is a reasonable means of ensuring the correct diagnosis and treatment

Intraoral transposition of pedicled temporalis muscle flap followed by zygomatic implant placement

Despite the recent advances of sophisticated reconstructive surgical techniques, management of maxillectomy defects continues to be challenging. For a selected group of patients, who cannot sustain a sophisticated microsurgical reconstructive procedure, a prosthetic obturator is indicated to separate the oral cavity from the sinonasal cavities. After the development of the osseointegration concept, dental implants have proven to be indicated for the rehabilitation of patients who underwent maxillectomy. Recently, surgeons can use a computer-assisted software package, which enables them to insert implants after a detailed analysis of the residual bone. For some patients with limited amount of residual maxillary bone, unusual surgical sites such as the zygomatic complex have been tested. We introduce a successful 2-step surgical procedure using a pedicled temporalis muscle flap and zygomatic implant placement to reconstruct a maxillary defect after oncological resection

Wavelength-scale stationary-wave integrated Fourier-transform spectrometry

Spectrometry is a general physical-analysis approach for investigating light-matter interactions. However, the complex designs of existing spectrometers render them resistant to simplification and miniaturization, both of which are vital for applications in micro- and nanotechnology and which are now undergoing intensive research. Stationary-wave integrated Fourier-transform spectrometry (SWIFTS)-an approach based on direct intensity detection of a standing wave resulting from either reflection (as in the principle of colour photography by Gabriel Lippmann) or counterpropagative interference phenomenon-is expected to be able to overcome this drawback. Here, we present a SWIFTS-based spectrometer relying on an original optical near-field detection method in which optical nanoprobes are used to sample directly the evanescent standing wave in the waveguide. Combined with integrated optics, we report a way of reducing the volume of the spectrometer to a few hundreds of cubic wavelengths. This is the first attempt, using SWIFTS, to produce a very small integrated one-dimensional spectrometer suitable for applications where microspectrometers are essential

Polymorphisms of Pyrimidine Pathway Enzymes Encoding Genes and HLA-B*40∶01 Carriage in Stavudine-Associated Lipodystrophy in HIV-Infected Patients

Altres ajuts: Fundación para la Investigación y Prevención del SIDA en España (FIPSE 36610, 36572/06); Red de Investigación en SIDA (RIS RD12/0017/0005, RD12/0017/0014).To assess in a cohort of Caucasian patients exposed to stavudine (d4T) the association of polymorphisms in pyrimidine pathway enzymes and HLA-B*40∶01 carriage with HIV/Highly active antiretroviral therapy (HAART)-associated lipodystrophy syndrome (HALS). Three-hundred and thirty-six patients, 187 with HALS and 149 without HALS, and 72 uninfected subjects were recruited. The diagnosis of HALS was performed following the criteria of the Lipodystrophy Severity Grading Scale. Polymorphisms in the thymidylate synthase (TS) and methylene-tetrahydrofolate reductase (MTHFR) genes were determined by direct sequencing, HLA-B genotyping by PCR-SSOr Luminex Technology, and intracellular levels of stavudine triphosphate (d4T-TP) by a LC-MS/MS assay method. HALS was associated with the presence of a low expression TS genotype polymorphism (64.7% vs. 42.9%, OR = 2.43; 95%CI: 1.53-3.88, P<0.0001). MTHFR gene polymorphisms and HLA-B*40∶01 carriage were not associated with HALS or d4T-TP intracellular levels. Low and high expression TS polymorphisms had different d4T-TP intracellular levels (25.60 vs. 13.60 fmol/10 6 cells, P<0.0001). Independent factors associated with HALS were(OR [95%CI]: (a) Combined TS and MTHFR genotypes (p = 0.006, reference category (ref.): 'A+A'; OR for 'A+B' vs. ref.: 1.39 [0.69-2.80]; OR for 'B+A' vs. ref.: 2.16 [1.22-3.83]; OR for 'B+B' vs. ref.: 3.13, 95%CI: 1.54-6.35), (b) maximum viral load ≥5 log10 (OR: 2.55, 95%CI: 1.56-4.14, P = 0.001), (c) use of EFV (1.10 [1.00-1.21], P = 0.008, per year of use). HALS is associated with combined low-expression TS and MTHFR associated with high activity polymorphisms but not with HLA-B*40∶01 carriage in Caucasian patients with long-term exposure to stavudine