Using computer-assisted method to teach children with intellectual disabilities handwashing skills.

PURPOSE: To motivate children with intellectual disabilities (ID) to learn handwashing and improve their performance by using computer-assisted teaching method. METHOD: A teaching program was implemented using a computerized teaching station with faucet, soap dispenser and towel dispenser as user interface. In response to the children's actions, animations were shown on the computer screen of the teaching station. A controlled study was conducted to compare the effectiveness of the proposed method (study group) with that of the convention teaching method (control group). Both groups of subjects attended a 30-min handwashing lesson twice per week for 2 months. Their performance was evaluated using a handwashing task checklist and a learning motivation questionnaire, and by measuring the completion time and assessing their hand cleanliness. RESULTS: The computer-assisted teaching program improved the handwashing performance and learning motivation of the subjects. The study group appeared to outperform the control group. Observations reflected that the subjects were highly motivated to learn handwashing with the computerized teaching station. CONCLUSION: The proposed method has the potential to facilitate the teaching and learning of handwashing skills for children with ID.

On the roles of solid-bound ligand scavengers in the removal of palladium residues and in the distinction between homogeneous and heterogeneous catalysis.

We have studied the roles and behavior of typical resin- and silica-bound thiol scavengers in the removal of palladium (Pd) residues and in the determination of the true catalytic species in the Heck coupling of bromobenzene and styrene. The results of Pd scavenging and catalyst poisoning by elemental analysis (EA) and transmission electron microscopy (TEM) indicate that silica-bound thiols have an advantage over resin-bound thiols in residual Pd removal from a Heck reaction solution and that all of these scavengers poison effectively the catalytic species but hardly scavenge Pd clusters, even as small as 1 nm from solution presumably because of the steric barrier. Because of a smaller proportion of soluble Pd clusters, using a molecular Pd precatalyst results in a much higher Pd scavenging efficiency than using a supported Pd particle precatalyst. With the aid of catalyst poisoning by the scavengers, filtration testing and TEM studies further illustrate that Pd clusters are inactive for the Heck reaction over Pd(0)/SiO(2), with molecular Pd(0) being solely active. Studies through EA and thermogravimetric analysis suggest that the bound thiols are leached from the scavengers to a different extent at reaction temperatures of 90-135 °C, probably owing to base-catalyzed decomposition or based-promoted dissociation of functional groups from the surfaces, leading to interaction between leached thiols and a solid Pd precatalyst. Meanwhile, the effect of solid-bound thiol binding to soluble Pd on the efficiency of Pd scavenging and the impact of a scavenger on the Pd leaching from supported Pd particles are discussed.

The amido-bridged zirconocene's reactivity and catalytic behavior for ethylene polymerization.

Reaction of the amido-bridged zirconium complex (CpSiMe(2)NSiMe(2)Cp)ZrCH(3) (1) (Cp = C(5)H(4)) with half an equivalent of B(C(6)F(5))(3) or Ph(3)CB(C(6)F(5))(4) afforded the binuclear zirconium complexes [(CpSiMe(2)NSiMe(2)Cp)Zr)(2)(mu-CH(3))][RB(C(6)F(5))(3)] (2a, R = CH(3), 2b, R = C(6)F(5)) with a methyl group as the bridge between the two zirconium atoms. In the presence of one equivalent of B(C(6)F(5))(3) or Ph(3)C(C(6)F(5))(4), 1 was transformed to the zwitterionic complexes [(CpSiMe(2)NSiMe(2)Cp)Zr][RB(C(6)F(5))(3)] (3a, R = CH(3), 3b, R = C(6)F(5)) which are free of a metal-bound sigma-alkyl ligand. 2b is stable with Me(3)Al while 3b combined with Me(3)Al to form a hetero-binuclear complex [(CpSiMe(2)NSiMe(2)Cp)Zr(mu-CH(3))]Al(CH(3))(2)][B(C(6)F(5))(4)] (4) as shown by NMR spectroscopy at room temperature. Treatment of 2a or 3a with an excess of Me(3)Al led to (CpSiMe(2)NSiMe(2)Cp)Zr(C(6)F(5)) (5) through a group exchange process. 2b, 3a and 5 have been characterized by X-ray diffraction studies. 2b, 2b, 3a and 3b were highly active catalysts for ethylene polymerization and copolymerization with 1-octene in the presence of trialkylaluminium, but the binuclear zirconium complexes (2a and 2b) showed higher activities than their mononuclear counterparts 3a and 3b. Polymerization activities varied with the trialkylaluminiums and increased with the trialkylaluminium concentration applied in the system. The product existed mainly in the form of Al(PE)(3) with polymeric chains, and its molecular weight and distribution were greatly influenced by the type and amount of trialkylaluminium applied in the catalytic system.