Cas Costa

Possibility of reducing the luteolytic dose of cloprostenol in cyclic dairy cows

The administration of cloprostenol by intravulvosubmucous (i.v.s.m.) injection at 1 2 and 1 4 of the dose usually given by intramuscular (i.m.) injection, was tested in dairy cows for luteolysis and estrus synchronization. The i.m. injection was used in ten adult cows at the usual dose of 500 mug/animal. Eleven adult cows and 11 heifers were treated i.v.s.m. with a dose equivalent to 250 mug/animal and 125 mug/animal, respectively. Two injections of cloprostenol were administered 11 days apart to the cows not detected in oestrus after a single injection. Forty-three out of the total 46 animals were detected to be in dioestrus at the time of at least one of the injections, as reflected by the plasma progesterone concentrations at the time of treatments. Three out of the 43 animals injected during dioestrus were refractory to the luteolytic effect of cloprostenol; this appeared to be independent of the dosage and the route of administration (refractory cows were: one adult cow treated i.m. and two treated i.v.s.m. with 125 mug of cloprostenol). The mean time interval from injection to the onset of heat was 82.8 hours with a confidence limit for 95% of probability between 67.9 hours and 92.7 hours. The difference between treatments is not significant. The results suggest that in heifers and adult cows cloprostenol can be given i.v.s.m. route at a reduced dose of 1 4 of the usual 500 mug i.m. dosage without affecting the luteolytic effect of the drug or fertility.

A 45° saw-dicing process applied to a glass substrate for wafer-level optical splitter fabrication for optical coherence tomography

This paper reports on the development of a technology for the wafer-level fabrication of an optical Michelson interferometer, which is an essential component in a micro opto-electromechanical system (MOEMS) for a miniaturized optical coherence tomography (OCT) system. The MOEMS consists on a titanium dioxide/silicon dioxide dielectric beam splitter and chromium/gold micro-mirrors. These optical components are deposited on 45° tilted surfaces to allow the horizontal/vertical separation of the incident beam in the final micro-integrated system. The fabrication process consists of 45° saw dicing of a glass substrate and the subsequent deposition of dielectric multilayers and metal layers. The 45° saw dicing is fully characterized in this paper, which also includes an analysis of the roughness. The optimum process results in surfaces with a roughness of 19.76 nm (rms). The actual saw dicing process for a high-quality final surface results as a compromise between the dicing blades grit size (#1200) and the cutting speed (0.3 mm s−1). The proposed wafer-level fabrication allows rapid and low-cost processing, high compactness and the possibility of wafer-level alignment/assembly with other optical micro components for OCT integrated imaging.

Design and fabrication of an endomicroscopic imaging module for minimally invasive medical devices

Medical imaging is an important part of diagnosis. The procedure should provide valuable information for diagnosis and, at the same time, should be minimally invasive for the patient. Therefore, when performing endoscopic imaging a system with reduced dimensions is crucial. The performance of imaging systems, used in several diagnosis endoscopic procedures, would highly benefit from the integration of an endomicroscopic imaging module (ENIM) able to perform in-vivo and real-time tissue microscopy. This paper proposes a miniaturized ENIM: its total length is 12.164 mm and has a lateral lens assembly of 3.894 mm. A microfabricated PDMS lens was included in the system, obtained by a hanging droplet approach, a very-low cost and effective method. A paraxial magnification of 14 times was achieved with a Modulation Transfer Function (MTF) around 38% at 50 lp/mm and maximum distortion about 1.8%.