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(Tsi)chlorosilylenoid [Tsi = C(SiMe3)3] reacted with acetaldehyde and benzaldehyde to give 2,4-dioxasilolane and 2,5-dioxasilolane, respectively. The direct addition of an aldehyde to a silaoxirane intermediate is proposed as a plausible mechanism based on a theoretical study. These results show a new synthetic application of the chlorosilylenoid and a new route for the synthesis of silaheterocycles.

The Cd1-x/Znx/Te film was produced by thermal evaporation for the flat-panel X-ray detector. The crystal structure and the surface morphology of poly crystalline Cd1-x/Znx/Te film were examined using XRD and SEM, respectively. The leakage current and X-ray sensitivity of the fabricated films were measured to analyze the X-ray response characteristic of Zn in a polycrystalline CdZnTe thin film. The leakage current and the output charge density of Cd0.7/Zn0.3/Te thin film were measured to 0.3 1nA/ and 260 pC/ at an applied voltage of 2.5 V/, respectively. Experimental results showed that the increase of Zn doping rates in Cd1-x/Znx/Te detectors reduced the leakage current and improved the X-ray sensitivity significantly. The leakage current was drastically diminished by the formation of thin parylene layer in the Cd0.7/Zn0.3/Te detector.

To overcome problems derived from the shaft within conventional centrifugal pumps, we have developed a new centrifugal pump, the magnetically suspended centrifugal pump (MSCP), which has no shaft and operates as a bearingless centrifugal pump. The impeller is suspended freely and centrally by magnetic force within the pump. Hemolysis tests were performed in comparison with the Biopump. Index of hemolysis and destruction of platelets were significantly lower in the MSCP than in the Biopump. Animal studies were designed to evaluate the durability and antithrombogenicity of the MSCP. Short-term animal studies were performed using two mongrel dogs. Left heart bypass was established with the MSCP. After 3 hr, the layer of thrombus adherent to the surface of the polycarbonate impeller impaired pumping efficiency. However, using the impeller coated with silicone, no thrombus was observed on the impeller after continuous pumping for 24 hr. In addition, long-term animal studies were performed using two sheep. Left heart bypass was established with the MSCP containing an impeller coated with silicone. In one sheep, the MSCP ran for 14 days without problems in pumping performance and showed no thrombus within the pump. In the other sheep, the MSCP ran for 15 days, and showed no thrombus on the impeller. During each experiment, plasma free hemoglobin levels were less than 15 mg/dl. The MSCP induced less hemolysis than did the Biopump, and the MSCP containing an impeller coated with silicone demonstrated the potential to run for 14 days without thrombus formation within the pump.

Functionalization of the [1 n ]orthocyclophanes ([1 n ]OCPs) has been accomplished by introducing groups on the aromatic rings of the cycles. Dilithiation of dibromoaromatic 10 followed by condensation with various aromatic dialdehydes, such-as 14, 20, and 30, gave rise to [1 n ]OCP cycles bearing methoxy groups on the aromatic rings. Several polymetho- xy[1 n ]OCPs have been prepared that are reasonably soluble in organic solvents, in contrast to their parent hydrocarbons. Since methoxy func- tions can be converted to phenolic hydroxy groups and then to other fu- nctionalities, the methoxy derivatives may have broad applications to the modification of [1 n ]OCPs for the preparation of a variety of supra- molecules

Synthetic studies of a new family of novel ketonic macrocycles are reported. Exhaustive oxidation of all of the methylenes in odd-numbered [1 n ]orthocyclophanes ([I n ]OCPs) resulted in the polyoxo derivatives of a cyclopolyorthobenzoyl or polyoxo[I n ]orthocyclophane constitution. This new class of ketonic crowns is referred to as [1 n ] orthocyclopha- nepolyones and includes [1 5 ]orthocyclophanepentaone, [1 7 ]orthocyclo- phaneheptaone, and [1 9 ]orthocyclophanenonaone. We suggest the generic name «ketonands» for these ketonic crowns. Structures of ketonands were confirmed by spectral and X-ray crystallographic analyses

Synthesis and functionalization of higher members of the [1 n ]orthocyclophanes, or [1 n ]OCPs, have been investigated. Oxidation of the benzylic methylenes in [1 n ]OCPs gave the polyoxo derivatives. Exhaustive oxidation of all methylenes in even-numbered [1 n ]OCPs gave rearranged isomers of the cyclopolyketal structure instead of the corresponding polyoxo derivatives. We propose the class name «starands» for this new family of crown compounds for their star-shaped crown ether structure. Detailed synthesis and characterization of two starands are described

[1 4 ]- and [1 5 ]orthocyclophanes have been designed, synthesized and characterized. Dimetalation of bis(2-bromophenyl)methane (14) to the corresponding dilithio reagent 21, followed by reaction with aromatic dialdehydes bis(2-formylphenyl)methane (20) and 1,2-bis(2-formylbenzyl)benzene (27), gave cyclic diols 22 and 28, respectively. Oxidation of the diols with PCC to the corresponding cyclic diketones 23 and 29, followed by palladium-catalyzed reduction, afforded [1 4 ]- and [1 5 ]orthocyclophanes, 4 and 5

Halosilylenoids, stable at room temperature (Tsi)X(2)SiLi (Tsi=C(SiMe(3))(3), X=Br, Cl), were synthesized from the reaction of TsiSiX(3) with lithium naphthalenide. Bromosilylenoid reacted with tBuOH and MeI both at -78 degrees C and at room temperature to give (Tsi)HSiBr(2) and (Tsi)MeSiBr(2), respectively, in high yields; this clearly shows its nucleophilicity. In the reaction of bromosilylenoid with methanol, 2-propanol, and 2,3-dimethyl-1,3-butadiene, the corresponding products, (Tsi)HSi(OMe)(2), (Tsi)HSi(OiPr)Br, and bromo(Tsi)silacyclopent-3-ene, were obtained in high yields; this demonstrates its amphiphilic property, as if bromosilylene would be trapped. Chlorosilylenoid also exhibited both nucleophilic and amphiphilic properties. The (29)Si chemical shifts for (Tsi)Br(2)SiLi, (Tsi)Br(2)SiK, and (Tsi)Cl(2)SiLi were 106, 70, and 87 ppm, respectively.

To overcome problems derived from the shaft within the conventional centrifugal pump, we have been developing a new centrifugal pump, namely a magnetically suspended centrifugal pump (MSCP), which has no shaft and operates as a noncontacting and bearingless pump. The impeller is suspended magnetically between the magnetic bearing and the driving motor. Hemolysis tests were performed in comparison with the Biopump (BP80, BioMedicus). The index of hemolysis (IH) was significantly lower in the MSCP than in the Biopump. In addition, a smaller gap in the MSCP induced lower hemolysis. In preliminary studies using mongrel dogs, the layer of thrombus adherent to the impeller was observed in a few hours, which impaired the pumping efficiency. However, by using an impeller coated with silicone, no aggregations of platelets or fibrin on the impeller were observed in 24 h of continuous pumping. In conclusion, the MSCP had a gentler influence on blood cells than the Biopump, and the impeller coated with silicone may contribute to the long-term pumping of the MSCP.