Platinum implantation

Ion implantation has also been used for the creation of novel catalyticaHy active materials. Ruthenium oxide is used as an electrode for chlorine production because of its superior corrosion resistance. Platinum was implanted in mthenium oxide and the performance of the catalyst tested with respect to the oxidation of formic acid and methanol (fuel ceU reactions) (131). The implantation of platinum produced of which a catalyticaHy active electrode, the performance of which is superior to both pure and smooth platinum. It also has good long-term stabiHty. The most interesting finding, however, is the complete inactivity of the electrode for the methanol oxidation. 

MOSFETT s, and silicon oxide is deposited. The source/drain positions where electrical contact is to be made to the MOSFETs are defined, using the oxide-removal mask and an etch process. For shallow trench isolation, anisotropic silicon etch, thermal oxidation, oxide fill and chemical mechanical leveling are the processes employed. For shallow source/drains formation, ion implantation techniques are still be used. For raised source/drains (as shown in the above diagram) cobalt silicide is being used instead of Ti/TLN silicides. Cobalt metal is deposited and reacted by a rapid thermal treatment to form the silicide. Capacitors were made in 1997 from various oxides and nitrides. The use of tantalmn pentoxide in 1999 has proven superior. Platinum is used as the plate material. 

In the work of Cabrales and coworkers73 (Cuba), sixty male BALBC mice were used and Ehrlich tumors were implanted in them. When the tumor volumes reached 850 mm,3 four platinum electrodes were inserted into each tumor ECT was carried out at 4 mA for 21 minutes, total charge thus passed through each tumor was around 5 coulombs. Tumor volume decrease and necrosis percentage increase were significant in mice treated with ECT, in comparison with the control group without ECT. 

Electrochemical Behavior of Titanium Implanted with Platinum (RBS)... 

Helix-electrodes contact peripheral nerves on a small area due to their open structure. They consist of a silicone rubber substrate with one or two embedded platinum wire electrodes (Fig. 1). They were developed at the Huntington Medical Research Institute (HMRI) in a monopolar and a bipolar version [17]. The latest versions have been applied in paralyzed people at the sacral spinal roots for micturition control and incontinence. Their advantage can be seen in the self-sizing properties due to the spiral structures when the nerve is affected by edematous swelling after the implantation trauma. 

The acute recording of evoked potentials and the stimulation at the spinal cord has been a well-established method for more than 20 years. The procedures require electrodes that are similar to pacemaker electrodes. Applications can be found in the field of skoliosis correction [38, 39] and the repair of aorta aneurysms [40]. An intraoperative stimulation of fibers of the sacral spinal cord was performed during dissection of unilateral testicle tumors to preserve ejaculation [41]. The main application of implants for chronic stimulation of the spinal cord is the handling of chronic pain [42]. There are two types of electrodes the percutaneous electrodes resemble the pacemaker electrodes. They consist of a mandrel with up to four ring electrodes of a platinum iridium alloy (Fig. 6). They have a length of 3 mm with an interelectrode distance of 6 mm or a length of 6 mm with an interelectrode distance of 12 mm. 

The electrodes are manufactured and distributed by MEDTRONIC (Minneapolis, USA). The epidural implantation is performed under local anesthesia. The second electrode type consists of four platinum disks that are embedded in a silicone rubber carrier. They have a diameter up to 6 mm (Fig. 7). They are implanted close to the spinal cord under complete ane sthesia. Surgical procedures have been developed from the early 1970s up to the present [43]. Current designs offer the possibility of externally correcting small dislocation of electrodes [44]. Meanwhile more than 300 patients have benefitted from this therapy. 

Dead Sarcoma-180 cells injected into mice do not cause tumors, neither do they induce an immune reaction to reimplanted live tumor cells. Here one must be cautious since only small numbers of live implanted cells ( 40) can eventually lead to large tumors and death. But cells treated with the platinum drug at low concentrations, 100 times less than the concentration required to produce extensive cell kill, implanted in the mice do not produce tumors, but do induce an immunologic rejection of pristine tumor cells implanted two weeks later. This experiment is difficult to interpret without invoking the immune system of the host in causing tumor cell death. 

Titaiuum is a silvery ductile metal with important industrial uses because it is less dense than iron, much stronger than aluminum, and almost as corrosion resistant as platinum. This rare combination of properties makes it ideal for a variety of uses, particularly in engines, aircraft frames, marine equipment, and industrial plants. Titanium metal and alloys also replace bone and serve in dental implants. At normal... 

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