A Tutorial Program: Collaboration Between Preservice and Inservice Teachers

Many elementary school teachers face severe time constraints working individually with students who need extra help or attention in mathematics. Sometimes, children who need this attention do not receive it. At the same time, critics of teacher education programs contend that preservice teachers do not receive enough hands-on experience teaching children. The Mathematics Tutorial Program is one attempt to address both of these issues. In this program, elementary grade children are identified by their classroom teachers as needing extra help in mathematics. They are paired with preservice elementary school teachers. Each preservice teacher tutors one or more elementary children for two 30-minute sessions each week for 6 to 24 weeks. They use manipulatives and a hands-on approach. The tutors reported professional gains from their contacts with classroom teachers, mathematics educators, and elementary children. Classroom teachers involved with the program commented on the children's improved selfesteem and confidence in mathematics. The children eagerly looked forward to the time with their tutors.     

Application of weakly ionized plasmas for materials sampling andanalysis

The use of weakly ionized plasmas as spectroscopic sources for materials sampling and analysis is reviewed. Plasma sources currently used for this purpose include direct-current and alternating-current plasmas, inductively coupled plasmas, microwave-induced plasmas, surface-wave plasmas, capacitively coupled plasmas, capacitive microwave plasmas, glow discharges, flowing afterglows, theta pinch discharges, exploding films and wires, and laser-produced plasmas. The authors give a summary of relevant characteristics of some of the plasma sources. Included are the source, common method of application, approximate detection limit for that method, applicability for solid sampling, susceptibility to matrix effects, approximate cost, and the most common usage for the method     

Efficient synthesis of an adenosine A2a agonist: glycosylation of 2-haloadenines and an N2-alkyl-6-chloroguanine

A convergent synthesis of adenosine A2a agonist 1 in the form of its maleate salt 2 was achieved. The key step in this approach was the highly selective 9beta-glycosylation reaction between 2-haloadenines or an N(2)-alkyl-6-chloroguanine and a D-ribose derivative containing a 2-ethyltetrazolyl moiety. Glycosylations of other purine derivatives were also examined, and the methods developed provide efficient access to a variety of adenosine analogues such as 2-alkylaminoadenosines, an attractive class of compounds with antiinflammatory activity.     

Studies of the biosynthesis of DTX-5a and DTX-5b by the dinoflagellate Prorocentrum maculosum: regiospecificity of the putative Baeyer-Villigerase and insertion of a single amino acid in a polyketide chain

The biosynthetic origins of the diarrhetic shellfish poisoning toxins DTX-5a and DTX-5b have been elucidated by supplementing cultures of the producing organism Prorocentrum maculosum with stable isotope labeled precursors and determining the incorporation patterns by 13C NMR spectroscopy. The amino acid residue in the sulfated side chain is found to originate from glycine, and oxygen insertion in the chain is shown to occur after polyketide formation.