Femtosecond laser writing of photonic devices in borate glasses compositionally designed to be laser writable.

The design and performance of borate glass samples compositionally pre-designed to be femtosecond laser writable via laser-induced ion migration is reported in this Letter. It is demonstrated that borate glasses modified on purpose with small amounts of La2O3 and Na2O can be straightforwardly used to produce high-index contrast (Δn) waveguides by femtosecond-laser-assisted ion migration. The positive Δn of the waveguides is caused by the local enrichment of La2O3 in the guiding region with a slope of 8·10-3(mol.%)-1. The value of this is consistent with numerical aperture measurements of the waveguides and local compositional measurements at the guiding region performed by energy-dispersive x-ray micro-analysis. The maximum achievable Δn values can be controlled through the initial La2O3 content of the glass. Maximum Δn values >10-2 for samples with just 5.5 mol. % of La2O3 have been produced. This compositional design approach could be potentially used to produce highly efficient femtosecond laser writeable glasses in other glass families.

Colgajo submental para reconstrucción de defectos oncológicos en cabeza y cuello / Submental flap to reconstruct oncologic head and neck defects

El colgajo submental es un procedimiento eficaz para lareconstrucción en el territorio maxilofacial. Caracterizado por su delgadez,versatilidad, excelente color y textura y mínima morbilidad enla zona donante, su utilización en lesiones malignas es controvertida,por el riesgo de trasladar enfermedad metastásica cervical a la zonareceptora. Material y métodos: Se presentan 3 casos clínicos en los quese ha aplicado en pacientes afectos de un carcinoma epidermoide decabeza y cuello. Describimos las particularidades anatómicas, y serealiza una revisión de la técnica quirúrgica. Resultados: Fueron óptimosen cuanto a cobertura del defecto, estética y función salvo por unanecrosis parcial en uno de ellos. En todos los casos la morbilidad en lazona donante fue mínima. Conclusiones: El colgajo submental es unaopción a considerar incluso en pacientes oncológicos sobre todo en losque, por edad avanzada o presentar patología asociada no están indicadosprocedimientos más agresivos(AU)

The submental flap is an effective option forthe reconstruction in the maxillofacial territory.Characterized by its thinness, versatility, excellent colourand texture and minimum morbidity in the donor zone,its use in malignant injuries is controverted by the riskof transferring cervical metastasic disease to the receivingzone. Material and methods: we present 3 clinical casesin which it has been used in patients affected by ansquamous cell carcinoma of head and neck. In addition,the anatomical particularities are described, and a revisionof the surgical technique is made. Results: They wereoptimal in relation to covering of the defect, aestheticsand function except for a partial necrosis in one of them.In all the cases the morbidity in the donor zone wasminimum. Conclusions: The submental flap is an optionto consider in oncologic patients, mainly in those whomby advanced age or by the existence of comorbidity adviceagainst the use of more aggressive procedures(AU)

Electron transport via local polarons at interface atoms.

Electronic transport is profoundly modified in the presence of strong electron-vibration coupling. We show that in certain situations, the electron flow takes place only when vibrations are excited. By controlling the segregation of boron in semiconducting Si(111)-square root 3 x square root 3 R 30 degrees surfaces, we create a type of adatom with a dangling-bond state that is electronically decoupled from any other electronic state. However, probing this state with scanning tunnelling microscopy at 5 K yields high currents. These findings are rationalized by ab-initio calculations that show the formation of a local polaron in the transport process.

Plasma membrane-bound carbonic anhydrase activity in the regenerating rat liver.

Part of the carbonic anhydrase activity of hepatocytes has been reported to be located in the plasma membrane. This strategic location suggests a physiological role other than that located within the cell and probably related to the specific secretory function of these cells. Furthermore, after two-thirds hepatectomy an enzymatic retrodifferentiation has been reported. We reasoned that liver regeneration probably affects the carbonic anhydrase activity in different ways depending upon its location and hence presumably physiological role. We measured, therefore, carbonic anhydrase activity in a soluble fraction or in a plasma membrane-enriched fraction obtained from liver homogenate from rats undergoing hepatectomy (two-thirds) one, three or seven days before liver resection and homogenation. No changes in carbonic anhydrase activity were found as far as soluble fraction was concerned. However, the carbonic anhydrase activity in plasma membrane was reduced (by 55%) soon after hepatectomy, there after it increased, returning to near control value at seven days. Lactate dehydrogenase activities in soluble and plasma membrane fractions were not modified by the regenerative process. Neither was 5'-nucleotidase activity determined in plasma membrane affected by liver regeneration. In summary, these results indicate a higher sensitivity of plasma membrane carbonic anhydrase activity to the regenerative process than soluble carbonic anhydrase activity. This suggests a different control of the turnover of these isoenzymes during rat liver regeneration. The phenomenon is consistent with a different physiological role for these activities; i.e., one (plasma membrane-bound carbonic anhydrase activity) may be involved in specific functions of differentiated hepatocytes, and another (soluble carbonic anhydrase activity) may be involved in general functions shared by both differentiated and undifferentiated cells.