No abstract

Endoscopic resection is a safe and effective modality for treating well-differentiated rectal carcinoids smaller than 10 mm in diameter. Discrepancies were observed between CR-E and CR-P. The risk factors for metastasis were tumor size, increased mitotic rate, and lymphovascular invasion.

Electroosmotic pumps are arguably the simplest of all pumps, consisting merely of two flow-through electrodes separated by a porous membrane. Most use platinum electrodes and operate at high voltages, electrolyzing water. Because evolved gas bubbles adhere and block parts of the electrodes and the membrane, steady pumping rates are difficult to sustain. Here we show that when the platinum electrodes are replaced by consumed Ag/Ag(2)O electrodes, the pumps operate well below 1.23 V, the thermodynamic threshold for electrolysis of water at 25 °C, where neither H(2) nor O(2) is produced. The pumping of water is efficient: 13 000 water molecules are pumped per reacted electron and 4.8 mL of water are pumped per joule at a flow rate of 0.13 mL min(-1) V(-1) cm(-2), and a flow rate per unit of power is 290 mL min(-1) W(-1). The water is driven by protons produced in the anode reaction 2Ag(s) + H(2)O → Ag(2)O(s) + 2H(+) + 2e(-), traveling through the porous membrane, consumed by hydroxide ions generated in the cathode reaction Ag(2)O(s) + 2 H(2)O + 2e(-) → 2Ag(s) + 2 OH(-). A pump of 2 mm thickness and 0.3 cm(2) cross-sectional area produces flow of 5-30 μL min(-1) when operating at 0.2-0.8 V and 0.04-0.2 mA. Its flow rate can be either voltage or current controlled. The flow rate suffices for the delivery of drugs, such as a meal-associated boli of insulin.

Although greater technical refinement is required for a minor resection in the superior part of the right side of the liver, laparoscopic right-sided liver resection is feasible and safe.

When a current or a voltage is applied across the ceramic membrane of the nongassing Ag/Ag(2)O-SiO(2)-Ag/Ag(2)O pump, protons produced in the anodic reaction 2Ag(s) + H(2)O → Ag(2)O(s) + 2H(+) + 2e(-) are driven to the cathode, where they are consumed by the reaction Ag(2)O(s) + H(2)O + 2e(-) → 2Ag(s) + 2 OH(-). The flow of water is induced by momentum transfer from the electric field-driven proton-sheet at the surface of the ceramic membrane. About 10(4) water molecules flowed per reacted electron. Because dissolved ions decrease the field at the membrane surface, the flow decreases upon increasing the ionic strength. For this reason Ag(+) ions introduced through the anodic reaction and by dissolution of Ag(2)O decrease the flow. Their accumulation is reduced by applying Nafion-films to the electrodes. The 20 μL min(-1) flow rate of 6 mm i.d. pumps with Nafion coated electrodes operate daily for 5 min at 1 V for 1 month, for 70 h when the pump is pulsed for 30 s every 30 min, and for 2 h when operating continuously.

Harnessing cathodic hydrogen atom generation, metals such as Pt, Pd, Cu, Au and Ni are directly electrodeposited on functionalized dielectric layers of 6 nm thick silicon oxide formed by thermal oxidation of c-Si substrate. Modifying the oxide layer with functional molecules and Au nanoparticles by simple wet chemistry, we can enhance electrodeposition efficiently and thereby electroplate nanoparticles of Pd and Pt to obtain such thin metal films. In particular, Au nanoparticles on amine-modified silicon oxides remarkably enhance electrodeposition of metal nanoparticles to create sturdy metal films on the dielectric layer, n + -Si/SiO 2 -NH 2 . Such enhancement is ascribed to good affinity of Au nanoparticles with electrodeposited metal as well as enhanced current density across the silicon oxide. For an example of potential applications, we show one-step electrodeposition Pd film on dielectric layers to fabricate conductometric hydrogen gas sensor without transferring Pd film. 8 and so on. Electrochemical methods 9,10 allow the solution process under fine and easy control without reducing agents by directly delivering electrons to precursors. Importantly, it can create stabilizer-free NPs or films with pristine surfaces that potentially serve as catalytically active sites for sensors and chemical reactions.11 Therefore, electroplating method has been widely considered as a cost-effective alternative. Especially, electro-synthesis of nanoparticles on conducting surfaces 12,13 has been attracting steady attention as highlighted by shape-control of nanoparticles using the programmed electrochemical methods on glassy carbon electrode. 14 Despite its valuable merits, programmed electro-synthesis can produce nanoparticles on the conducting electrode, while need to be transferred to other substrates, mostly dielectric materials, for practical applications in many cases. Recently reported strategy gives an inspiration of direct electrodeposition on dielectric layer; Pd NPs deposited on n + -Si/thermal SiO 2 . 15 It appears to be counterintuitive to electroplate on insulating substrates but it works owing to electrogenerated hydrogen (H) atoms in the thermal SiO 2 layer. H atom-mediated electro-reduction on thermal SiO 2 layers can be finely controlled by not only the applied bias but also pH in the solution, producing pristine Pd NPs deposited without any stabilizer or additive. H atoms, which are created by reduction of protons migrating across thermal SiO 2 layers, are expected to make precursors reduced at the interface between SiO 2 and solution. Indeed, this suggests a new breakthrough toward direct electroplating technology for thin metal films on dielectric layer.There are a few critical issues to overcome. Low density of current carried by H atoms and poor affinity of metal onto pristine SiO 2 are likely to make the metal grow too slow to be a film. Furthermore, there is a limitation in uniformity of particles in terms of both size and shape. For fine and steady control of electroplating process, it is undesir...

A programmable, skin-attached, 36 × 30 × 8 mm system for subcutaneous infusion of 1.2 mL of a drug solution is described. The system is intended to be replaced daily. It comprises a 20 × 14 × 8 mm electronic controller and power source, an 8 mm diameter 2 mm thick electroosmotic pump, a two-compartment reservoir for a pumped water and a drug solution, an adhesive tape for attachment to the skin, and a 6 mm long 27 gauge needle. Its removable electronic controller programs the dose rate and dose and is re-used. The electroosmotic pump consists of a porous ceramic membrane sandwiched between a pair of Ag/Ag2O plated carbon paper electrodes. It operates below 1.23 V, the thermodynamic threshold for water electrolysis without gassing. The flow rate can be adjusted between 4 and 30 μL min(-1) by setting either by the voltage (0.2-0.8 V) or the current (30-200 μA). For average flow rates below 4 μL min(-1), the pump is turned on and off intermittently. For example, a flow rate of 160 μL day(-1), i.e., 0.13 μL min(-1) for basal insulin infusion in type 1 diabetes management, is obtained when 10 s pulses of 75 μA is applied every 15 min. High flow rates of 10-30 μL min(-1), required for prandial insulin administration, are obtained when the pump operates at 50-200 μA. To prevent fouling by the drug, only pure water passes the pump; the water pushes a drop of oil, which, in turn, pushes the drug solution.

The faradaic reaction at the insulator is counterintuitive. For this reason, electroorganic reactions at the dielectric layer have been scarcely investigated despite their interesting aspects and opportunities. In particular, the cathodic reaction at a silicon oxide surface under a negative potential bias remains unexplored. In this study, we utilize defective 200-nm-thick n+-Si/SiO2 as a dielectric electrode for electrolysis in an H-type divided cell to demonstrate the cathodic electroorganic reaction of anthracene and its derivatives. Intriguingly, the oxidized products are generated at the cathode. The experiments under various conditions provide consistent evidence supporting that the electrochemically generated hydrogen species, supposedly the hydrogen atom, is responsible for this phenomenon. The electrogenerated hydrogen species at the dielectric layer suggests a synthetic strategy for organic molecules.