Characterization of femtosecond laser written waveguides for integrated biochemical sensing

Fluorescence detection is known to be one of the most sensitive among the different optical sensing techniques. This work focuses on excitation and detection of fluorescence emitted by DNA strands labeled with fluorescent dye molecules that can be excited at a specific wavelength. Excitation occurs via optical channel waveguides written with femtosecond laser pulses applied coplanar with a microfluidic channel on a glass chip. The waveguides are optically characterized in order to facilitate the design of sensing structures which can be applied for monitoring the spatial separation of biochemical\ud species as a result of capillary electrophoresis

Effects of native plants extracts from Córdoba Argentina over foraging activity of the cutting ant Acromyrmex lundi (Guérin)

In the search for new alternatives for insect pest management, natural products from plants are an option currently studied for being substances of low toxicity and biodegradable. The leaf-cutting ant Acromyrmex lundi is a very important herbivorous species in the Argentine Chaco phytogeographic region as it can cut various parts of plants and attack almost all cultivated species. The objectives of this study were: 1. determine the effect of plant extracts native of Córdoba-Argentina on the foraging activity of A. lundi in an artificial nest. 2. evaluate the crude extract with highest activity in foraging activity field tests. Extracts were prepares with aerial parts of plants belonging to 28 botanical families. In the laboratory, an artificial nest was installed, which consisted of a main chamber where the queen, the immature and the fungus remained, and smaller chambers that operated as dump and foraging areas. The work was carried out under controlled conditions (27°C, 12:12 hs light/darkness and Hº 25± 3). In free-choice tests, 8 discs of rose leaves of 1 cm of diameter were impregnated with 10μl per cm2 of a 1% solution (10 ug / ul) of each extract or solvent (control). The Inhibitory Dose 50 (ID50) was determined for all the extracts that showed 100% repellency. Aristolochia argentina Griseb. showed the lowest DI50 values, for what it was chosen for field trials. Rose leaves treated with A. argentina extract (1% and 5%) and others with acetone (control) were placed on either side of an actively foraging path of six active nests of A. lundi, 50cm from the nest opening. The percentage of removed material was registered within two hours of observation and on two consecutive days, ending the trial when removed 50% of the total substrate provided. Also, foraging activity was determined by counting at a fixed point and for a period of three minutes, the number of workers who went towards the mound charged. In field trials, the 1% extract of A. argentina (n = 6) did not affect foraging activity (P> 0.05), whereas the 5% dose (n = 5) showed significant differences between treatments (P <0.05). From these preliminary results, future studies arise to deepen different effects of the compound oriented to leaf-cutting ants management.Fil: Nolli, L.C. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Cátedra de Entomología; Argentina.Fil: Nolli, L.C. Centro de Investigaciones Entomológicas de Córdoba; Argentina.Fil: Buffa, L.M. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Cátedra de Entomología; Argentina.Fil: Buffa, L.M. Centro de Investigaciones Entomológicas de Córdoba; Argentina.Fil: Defagó, M. T. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Cátedra de Entomología; Argentina.Fil: Defagó, M. T. Centro de Investigaciones Entomológicas de Córdoba; Argentina.Fil: Diaz Napal, G. Universidad Católica de Córdoba. Facultad de Ciencias Químicas. Laboratorio de Química Fina y Productos Naturales; Argentina.Fil: Palacios, S. M. Universidad Católica de Córdoba. Facultad de Ciencias Químicas. Laboratorio de Química Fina y Productos Naturales; Argentina.Zoología, Ornitología, Entomología, Etologí

Integration of femtosecond laser written waveguides for optical detection in microfluidic chips

Optical waveguides have been fabricated focusing femtosecond laser pulses into a commercial microfluidic chip. The waveguides intersect the channels and are used to optically excite their content. Fluorescence from the optically addressed volume is efficiently collected by a fiber, resulting in an highly compact and portable setup

Postite lichenoide mastocitaria

A 59 years-old man presented a single erythematous patch, with a cord-like infiltrated upper margin for one year localized to the coronal sulcus and prepuce mucosa of his penis. The patient was in good general health and had not used any kind of systemic or topical drugs for the past three months. Microbiologic laboratory study of the lesion excluded presence of Candida species. The histopathologic findings from a 4 mm punch biopsy were characterized by a band-like infiltrate, obscuring the dermo-epidermal junction. The infiltrate was made of a prevalence of mastocytes (toluidine blue and Giemsa stains) and lymphocytes. The case was provisionally defined «Lichenoid posthitis with mast cell». Histopathologically, there are only a few lichenoid dermatitides which involve the penis, i.e. lichen planus, lichen planus-like drug eruption, lichenoid lupus erithematosus. The prevalence of mastocytes is unusual and excludes a diagnosis of lichen planus, lichen planus-like drug eruption and lichenoid lupus erithematosus. Although the infiltrate in our case was lichenoid and some necrotic keratinocytes were present, like in true lichen planus, the infiltrate contained several mastocytes. The absence of plasma cells and of eosinophils excluded both a diagnosis of balanitis circumscripta plasmacellularis and a lichen planus-like drug eruption. The tentative explanation for the massive presence of mastocytes in this lichenoid infiltrate remains a matter of speculation