An electrochemical liquid-liquid-solid process that produces unlimited amounts of crystalline semiconductor, such as Ge or Si, from aqueous or polar solutions with tunable nanostructured shapes without any physical or chemical templating agent is presented. The valve coil is directed to a bottom which is connected to the frame-shaped wall portion and protects the valve coil after assembly of the valve coil support on the pressure control device against the effects of moisture, and wherein the valve coil for installation in the valve coil support is inserted into the frame-shaped wall portion exclusively in the direction of the bottom. In particular, the apparatus involves a retractor apparatus having one or more opposing blades having a channel adapted to engage an incision in a patient. The second electrode includes an opening section and a step section receding toward the first surface from the second surface. A second check valve permits one-way passage of fluid from the pump chamber, when it is compressed, into the main chamber.