Strong coupling between mechanical modes in a nanotube resonator.

We report on the nonlinear coupling between the mechanical modes of a nanotube resonator. The coupling is revealed in a pump-probe experiment where a mode driven by a pump force is shown to modify the motion of a second mode measured with a probe force. In a second series of experiments, we actuate the resonator with only one oscillating force. Mechanical resonances feature exotic line shapes with reproducible dips, peaks, and jumps when the measured mode is commensurate with another mode with a frequency ratio of either 2 or 3. Conventional line shapes are recovered by detuning the frequency ratio using the voltage on a nearby gate electrode. The exotic line shapes are attributed to strong coupling between the mechanical modes. The possibility to control the strength of the coupling with the gate voltage holds promise for various experiments, such as quantum manipulation, mechanical signal processing, and the study of the quantum-to-classical transition.

Chemical functionalization of polysilicon microparticles for single-cell studies.

In this work, two types of polycrystalline silicon (polysilicon) microparticles were modified with specific ligands in order to be selectively attached to chemical residues located at the plasma membrane and thus to be applied to study individual cells in culture. Two different functionalization approaches based on adsorption and covalent attachment were assayed. A comparative study of the efficiency of the ligand immobilization and stability of the modified particle in the culture medium was carried out using the selected ligands labeled with a fluorophore. Cylindrical microparticles (nonencoded microparticles) and shape-encoded microparticles (bar codes) were used with the aim of demonstrating the nondependence of the particle size and shape on the efficiency of the immobilization protocol. Fluorescence imaging and statistical analysis of the recorded fluorescence intensity showed that the covalent attachment of the ligand to the surface of the microparticle, previously modified with an aldehyde-terminated silane, gave the best results. As a proof of concept, Vero cells in culture were labeled with the covalently modified bar codes and successfully tracked for up to 1 week without observing any alteration in the viability of the cells. Bar code numbers could be easily read by eye using a bright-field optical microscope. It is anticipated that such modified microparticles could be feasible platforms for the introduction of other analytical functions of interest in single-cell monitoring and cell sorting in automatic analysis systems.

Nanomagnets with high shape anisotropy and strong crystalline anisotropy: perspectives on magnetic force microscopy.

We report on a new approach for magnetic imaging, highly sensitive even in the presence of external, strong magnetic fields. Based on FIB-assisted fabricated high-aspect-ratio rare-earth nanomagnets, we produce groundbreaking magnetic force tips with hard magnetic character where we combine a high aspect ratio (shape anisotropy) together with strong crystalline anisotropy (rare-earth-based alloys). Rare-earth hard nanomagnets are then FIB-integrated to silicon microcantilevers as highly sharpened tips for high-field magnetic imaging applications. Force resolution and domain reversing and recovery capabilities are at least one order of magnitude better than for conventional magnetic tips. This work opens new, pioneering research fields on the surface magnetization process of nanostructures based either on relatively hard magnetic materials-used in magnetic storage media-or on materials like superparamagnetic particles, ferro/antiferromagnetic structures or paramagnetic materials.

3-D modulable PDMS-based microlens system.

The design, simulation, fabrication and characterization of 3-D modulable micro-optical system based on poly-dimethilsiloxane (PDMS) are presented in this paper. This system consists on two uncoupled PDMS lenses with different diameter (2 and 10 microm). Under stretching conditions, the dimensions of the small lens are not modified, whereas the geometry of the bigger lens is shifted from spherical to elliptical. A combination of different technologies is used to fabricate this microsystem: silicon, polymer and soft-lithography microfabrication techniques. This combination allows obtaining structures with a simple and mass production technology. Experimental results confirm the predicted numerical simulations, showing that, when the structure is under stretching conditions, the first focus is virtually invariable whereas the second focus becomes a Sturm zone.

Silicon-nanowire based attachment of silicon chips for mouse embryo labelling.

The adhesion of small silicon chips to cells has many potential applications as direct interconnection of the cells to the external world can be accomplished. Hence, although some typical applications of silicon nanowires integrated into microsystems are focused on achieving a cell-on-a-chip strategy, we are interested in obtaining chip-on-a-cell systems. This paper reports the design, technological development and characterization of polysilicon barcodes featuring silicon nanowires as nanoscale attachment to identify and track living mouse embryos during their in vitro development. The chips are attached to the outer surface of the Zona Pellucida, the cover that surrounds oocytes and embryos, to avoid the direct contact between the chip and the embryo cell membrane. Two attachment methodologies, rolling and pushpin, which allow two entirely different levels of applied forces to attach the chips to living embryos, are evaluated. The former consists of rolling the mouse embryos over one barcode with the silicon nanowires facing upwards, while in the latter, the barcode is pushed against the embryo with a micropipette. The effect on in vitro embryo development and the retention rate related to the calculated applied forces are stated. Field emission scanning electron microscopy inspection, which allowed high-resolution imaging, also confirms the physical attachment of the nanowires with some of them piercing or wrapped by the Zona Pellucida and revealed extraordinary bent silicon nanowires.

Cytologic, cytochemical, immunocytochemical and ultrastructural diagnosis of a sacrococcygeal chordoma in a fine needle aspiration biopsy specimen.

The cytologic, cytochemical, immunocytochemical and ultrastructural findings on the aspirated material are presented for the case of a 57-year-old man with sacrococcygeal chordoma diagnosed by fine needle aspiration biopsy. Cytologically, two types of cellular elements were differentiated: medium-sized cells with few cytoplasmic vacuoles and classic physaliferous cells. Both types showed marked cytoplasmic positivity for keratin and S-100 protein; the absence of nuclear positivity in the physaliferous cells was notable. Ultrastructural study demonstrated the existence of true intracytoplasmic vacuoles and frequent rough endoplasmic reticulum-mitochondria complexes. The cytologic differential diagnosis with chondrosarcoma, myxoid liposarcoma, ependymoma and metastases of mucosecretory carcinomas is reviewed.

Bullous solar elastosis.

Solar elastosis (SE) is a well-recognized manifestation of chronic sun exposure, mainly affecting white patients. Well-established clinical manifestations of SE include Favre-Racouchot syndrome, cutis rhomboidalis nuchae, actinic comedonal plaques, elastomas, elastotic nodules of the ears, elastotic bands, collagenous plaques of the hands and colloid millia. Bullous SE is a very unusual presentation of SE, which consists clinically of tense bullae on chronically sun-damaged skin and is characterized histopathologically by a dermal cleft within a dermis with severe SE. Bullous SE is a rare but characteristic clinical expression of SE.

Light coupling into an optical microcantilever by an embedded diffraction grating.

By measuring the excitation efficiency of an optical waveguide on a diffraction grating one can accurately register the changes in the incidence angle of the exciting light beam. This phenomenon was applied to detect ultrasmall deflections of silicon dioxide cantilevers of submicrometer thickness that were fabricated with corrugation on top to act as diffraction grating couplers. The power of light coupled into the cantilevers was monitored with a conventional photodetector and modulated using mechanical vibration of the cantilever, thus changing the spatial orientation of the coupler with respect to the incident light beam. The technique can be considered as an alternative to the methods known for detection of cantilever deflection.

Adnexal tumour of probable Wolffian origin. Report of a case.

An adnexal tumour of probable Wolffian origin occurring in a 36 year old woman is reported. The lesion was asymptomatic and incidentally discovered during laparotomy. No recurrences have been demonstrated to date. Its origin from Wolffian remnants is briefly.

Adenomyoepithelioma of the breast. Report of two cases.

The clinical and pathologic findings of two cases of adenomyoepithelioma of the breast are reported. Aspiration cytology was performed in one case and was interpreted as malignant. Conversely, histological features revealed their typical architectural arrangement and immunohistochemical profiles confirmed that myoepithelial (actin and S-100 protein +) and epithelial (keratin and epithelial membrane antigen +) cells were active components in both tumours.

Embarazo ectópico ovárico primario resuelto mediante laparoscopia / Primary ovarian pregnancy and laparoscopic therapy

El embarazo ectópico de localización en el ovario (EEO) es una forma poco frecuente de presentación, cuya incidencia oscila entre 1:7000-40000 embarazos y corresponde al 0.5 por ciento - 6 por ciento de las gestaciones extrauterinas. En la actualidad el diagnóstico precoz utiliza la laparoscopia quirúrgica con excelentes resultados: menor estancia hospitalaria, recuperación posoperatoria temprana, menor formación de adherencias y mejor pronóstico reproductivo. Se presenta el caso de mujer de 36 años con EEO de 5,1 semanas de gestación en la que mediante laparoscopia se extrajo el embarazo, lográndose una evolución satisfactoria (AU)