In situ fabrication of ultrathin porous alumina and its application for nanopatterning Au nanocrystals on the surface of ion-sensitive field-effect transistors.

In situ fabrication in a single step of thin films of alumina exhibiting a thickness of less than 100 nm and nanopores with a highly regular diameter distribution in order to pattern nanostructures over field-effect devices is a critical issue and has not previously been demonstrated. Here we report the fabrication in situ of 50 nm thick ultrathin nanoporous alumina membranes with a regular pore size directly over metal-free gate ion-sensitive field-effect transistors. Depositing thin films of aluminum by an electron beam at a relatively low rate of deposition on top of chips containing the transistors and using a conventional single-step anodization process permits the production of a well-adhering nanoporous ultrathin layer of alumina on the surface of the devices. The anodization process does not substantially affect the electrical properties of the transistors. The small thickness and pore size of ultrathin alumina membranes allow them to be sequentially employed as masks for patterning Au nanocrystals grown by an electroless approach directly on the top of the transistors. The patterning process using a wet chemical approach enables the size of the patterned crystals to be controlled not only by the dimensions of the pores of alumina, but also by the concentration of the reactants employed. Surface modification of these nanocrystals with alkanethiol molecules demonstrates that the electrostatic charge of the functional groups of the molecules can modulate the electrical characteristics of the transistors. These results represent substantial progress towards the development of novel nanostructured arrays on top of field-effect devices that can be applied for chemical sensing or non-volatile memories.

The effects of dimensionality on electrochemical sensors based on carbon nanotubes and metallic nanowires.

Electrochemistry based unidimensional nanoelectrodes, such as carbon nanotubes and metallic nanowires, is now a reality that is leaving the academy and reaching a broad range of high-tech companies around the world. The intrinsic properties of electron-electron interactions, sizes and geometries significantly differentiate those nanostructures from conventional macroelectrodes or electrodes with sizes in a millimetric range. The inherent properties as well as the configuration of carbon nanotubes and metallic nanowires as electrochemical sensors are the main focus of this review. Applications and some future trends on developing of a clear pathway for assembly and integration of these into functional materials, are summarized as well.

Microdermabrasion with chemical peel.

Microdermabrasion is a popular, noninvasive superficial skin treatment. The author describes the benefits of microdermabrasion combined with a trichloroacetic acid peel to improve the appearance of moderately deep rhytids, acne scars, and photodamaged skin.

Treatment of osteoradionecrosis by transoral hemimandibulectomy: report of case.

A case of progressive osteoradionecrosis after cobalt-60 radiation has been presented. A rational, but aggressive, treatment has been described. The morbidity of the procedure is minimal when proper instrumentation is available. The postoperative results are esthetically pleasing because, with radiation, there is so much fibrosis that facial contour is satisfactory even after a hemimandibulectomy.