Novel concept for visible and near infrared spectro-interferometry: laser-written layered arrayed waveguide gratings.

With the growing complexity of astronomical instruments devoted to interferometry, such as MATISSE (a 4 telescope beam combiner) or FIRST (a 9 sub-apertures beam combiner), and the rebirth of space projects such as LIFE (a mid-infrared interferometer), integrated optics devices can be an interesting and complementary approach for beam combination of a large number of apertures. Moreover, one of the approaches for beam combination is pairwise combination of the inputs (either from individual telescopes or from aperture masking on a single telescope), which scales as N(N-1)/2 for an N input system. Astrophotonics devices are attractive to reduce mass and system complexity, while achieving all the beam combination in a single chip, even for a high number of inputs. The aim of this work is to develop a compact photonic device for astronomical applications and demonstrate a proof-of-concept of a spectro-interferometer. In this paper ultrafast laser inscription is used to fabricate three arrayed waveguide gratings (AWGs) stacked vertically. This arrangement enables spectral dispersion and interferometry to be measured simultaneously. Individual AWGs were designed for operation at 633 nm, and demonstrated at 633nm and 830nm. A scan between 790 and 830nm was also achieved to study the wavelength behavior of the AWG. Using a segmented mirror, light at 633nm or 830nm was injected simultaneously into three AWGs layered 40 µm apart, showing analogous behavior for all three layers and no unexpected crosstalk. Finally the three outputs were vertically combined to obtain interference fringes, showing the feasibility of spectro-interferometry and opening the way for compact astrophotonic devices devoted to phase closure studies, used in astronomy to reduce the effect of atmospheric turbulence.

Are hepatocellular carcinoma surveillance programs effective at improving the therapeutic options.

AIM: to evaluate whether the current surveillance programs (ultrasonography and alpha-fetoprotein testing every six months) are successful in detecting patients in the early stages. MATERIAL AND METHODS: the health records of all patients diagnosed with hepatocellular carcinoma in Donostia Hospital between 2003 and 2005 were reviewed retrospectively. Eighty-five patients (11 women and 74 men) were included in the study and demographic data, risk factors and clinical data were obtained. Patients were split into two groups according to whether or not they had been included in a surveillance program. RESULTS: seventy per cent of patients of the surveillance group is diagnosed in early stage opposite to 26.7% of patients in no surveillance group (p < 0.05). Thirteen patients cannot receive curative treatment in spite of the diagnosis in early stage (9 in the surveillance group and 4 in the no surveillance group. The global sensibility of the surveillance program in our series is 95%. CONCLUSIONS: current hepatocellular carcinoma surveillance programs, which comprise six-monthly ultrasonography and alpha-fetoprotein tests, are highly sensitive and effective. These programs result in the detection of hepatocellular carcinoma in its early-stages, when potentially curative treatment may be offered.

[Gastrointestinal hemorrhage secondary to heterotopic jejunal pancreas]. / Hemorragia digestiva secundaria a páncreas heterotópico yeyunal.

A case of heterotopic pancreas located in the small intestine is herewith presented. The 19-years male patient had been admitted three times since 1991 for an anemic syndrome secondary to melena. The origin of the hemorrhage was not determined with the studies performed (intestinal transit, opaque enema, esophagogastroscopy, colonoscopy and gammagraphy with technetium 99). On the last admission a vascular lesion low flow was observed on arteriography of the upper mesenteric artery on the mesenteric edge of the proximal jejunum. Following laparotomy a small tumor was found in the jejunum and 5 cm of the intestine including the tumor was resected. The anatomic pathologic results demonstrated a heterotopic pancreas.