Nanostructures are becoming increasingly important for technology and basic science. 1 Fabrication techniques currently employed for material deposition include low-pressure chemical vapor deposition (LPCVD), 2 laser-assisted chemical vapor deposition (LCVD), 3 plasma-enhanced chemical vapor deposition (PECVD), 4,5 ultraviolet stereo lithography, 6 spinning, 7 dipping, 8 spraying, 9 and electrodeposition. [10][11][12][13][14][15] Electrodeposition methods have many advantages over the other stated techniques and are attractive, as they are simple, inexpensive, reproducible, and damage-free. In addition, many materials can be deposited using electrodeposition, including metals, metal alloys, conducting polymers, and semiconductors with essentially no limitations on the size of the substrate or on the thickness of the deposited material. 16 Scanning probe microscopy (SPM) such as scanning tunneling microscopy (STM), 17 atomic force microscopy (AFM), 18 and scanning electrochemical microscopy (SECM) 19 has been widely used as a tool for surface imaging with atomic resolution. Furthermore, creation of structures using SPM has lately attracted considerable attention. 20-23 Using SPM for surface modification has advantages in that the modification process can be followed in real time and submicrometer resolution can be achieved. 24-25 SPM-based nanofabrication has potential uses in applications such as high-density information storage, high-resolution lithography, and production of nanoscale integrated chemical systems and electronic devices.Several groups have employed SPM to deposit metal and polymer microstructures. [28][29][30][31] Bard et al. 32 used the SECM to deposit different metals (e.g., Cu, Ag, Au, Pd) on polymer-coated substrates, whereas Shahat and Mandler et al. used the same technique to deposit Ni(OH) 2 structures 33 from aqueous solutions by changing the pH locally on the substrate and gold patterns by the controlled dissolution of a gold ultramicroelectrode (UME) tip. 34 Wipf and Zhou 35 used the "microreagent" SECM mode to deposit conducting polyaniline patterns on different substrates. Lagraff and Gewirth 36 employed the tip of an AFM to direct the growth of nanoscopic copper protrusions, whereas Madden and Hunter used a tip-directed scheme to deposit several micrometer-scale nickel structures. 25 In tip-directed localized deposition, 32 a faradaic current flows through the solution between a UME tip and a metal substrate electrode all immersed in an ionically conducting electrolyte when a bias voltage is applied between these two electrodes. If reducible metal ions are present in the electrolyte (e.g., Cu 2ϩ ions) and the substrate electrode potential is negative with respect to the tip electrode, then the passage of the faradaic current results in the deposition of metal on the substrate and an oxidation process at the tip. The magnitude of the faradaic current is kept constant by means of a conventional feedback control that monitors the current and adjusts the interelectrode spacing according...

This work demonstrates the electrodeposition of micrometer scale copper structures including columns and interconnectors. Copper interconnectors of 25 pm width were grown within an integrated circuit package using a simple instrument based on the scanning electrochemical microscope. In the present instrument electrodeposition is localized by applying a voltage between a closely spaced glass insulated Pt disk tip (diameter ca. 25 pm) and a substrate, all immersed in a plating solution of acidified Cu SO,. The parameters that affect the deposition process are also addressed.

High dielectric constant BaTiO 3 /ethyl cellulose (BT/EC) nanocomposites having BT loadings of up to 13 vol% were fabricated through a simple casting technique. The BT filler powder, synthesized through an ultrasonicassisted solid-state route, was revealed by X-ray powder diffractometry (XRD) and Raman spectroscopy to be dominantly tetragonal. Scanning electron microscopy (SEM) showed good dispersion of the BT nanoparticles in the EC polymer matrix at lower BT concentrations. However, at higher concentrations, the BT particles form a continuous phase or a "filler network" leading to weak BT/EC interactions. This finding is well supported by the results of the tensile strength and storage modulus. The dielectric properties of the BT/EC nanocomposites were investigated over wide ranges of frequency and temperature. The addition of BT significantly increased the permittivity (e 0 ) and dielectric loss (e 00 ) and improved the ionic conductivity of the EC. The electric modulus (M 00 ) results were analyzed in terms of the Havriliak-Negami function through three distinct relaxation mechanisms (namely a, b*, and b relaxations) in the temperature range 30-1508C. The dc conductivity (r dc ) results suggest that the BT/EC nanocomposites formed at low BT loading (up to 7.0 vol%) and a temperature of £ 608C are good candidates for antistatic applications while those formed at higher concentrations and temperatures are recommended for use in electrostatic dissipation applications.

The two major Nicotiana tabacum tobacco cembranoids, (1 S,2 E,4 R,6 R,7 E,11 E)-2,7,11-cembratriene-4,6-diol (1) and its C-4 epimer, exhibit a wide range of interesting biological activities. Although the tumorigenesis inhibition activity of tobacco cembranoids have been known since the mid 1980's, only a limited number of investigations have targeted their optimization and structure-activity relationship. This study reports the isolation of the new (1 S,2 E,4 S,6 E,8 S,11 E)-2,6,11-cembratriene-8- O-methyl-4,8-diol (3) and the known (1 S,2 E,4 R,6 R,7 E,11 E)-2,7,11-cembratriene-4- O-methyl-4,6-diol (2) from fresh N. tabacum leaves. Cembranoid 2 showed good anti-migratory activity against prostate cancer cell lines, and was therefore subjected to microbial transformation and semisynthetic optimization studies. Biotransformation of 2 using the fungal strains Cunninghamella NRRL 5695 and Mucor ramannianus ATCC 9628 afforded new ( 4 and 5) and known ( 6 and 7) metabolites. Semisynthetic esterification, oxidation, epoxidation, and reaction with Lawesson's reagent afforded the new products 8- 14. Cembranoid 2 and its epoxidation product 9 showed potent anti-migratory activities against the highly metastatic human prostate cancer cell lines PC-3M-CT+ (spheroid disaggregation assay) and PC-3 (wound-healing assay).

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