A new elongation reaction of three carbon units

A new modification of Peterson reaction leading to elongation of three carbon units by treatment of aldehydes with titanium ate complex, prepared from 1-lithio-1-(1-alkoxy)allyltrimethylsilane and titanium(IV) isopropoxide, is described.     

Synthesis of [Glu34]human splenin (hSP) and examination of its immunological effect on the reduced B-lymphocytes of uremic patients

[Glu34]human splenin (hSP) was synthesized in a conventional manner by assembling ten peptide fragments followed by deprotection with 1 M trifluoromethanesulfonic acid-thioanisole (molar ratio, 1:1) in trifluoroacetic acid in the presence of m-cresol and dimethylselenide. Finally, the deprotected peptide was incubated with dithiothreitol to reduce sulfoxide on the methionine side chain. Incubation of peripheral lymphocytes isolated from uremic patients with the synthetic [Glu34]hSP showed an enhancing effect on the reduced B-lymphocytes, but synthetic human thymopoietin (hTP) had no effect under the same conditions.     

Synthesis of a thymosin beta 4-like peptide, thymosin beta Met9, and its effect on low E-rosette-forming lymphocytes of lupus nephritis patients

A thymosin beta 4-like peptide, thymosin beta Met9 isolated from pork spleen, was synthesized using a conventional solution method. The deprotection of the protected thymosin beta Met9 was achieved by treatment with Zn-90% AcOH to remove C-terminal p-nitrobenzyl ester and then with 1 M trifluoromethanesulfonic acid-thioanisole (molar ratio, 1:1) in trifluoroacetic acid in the presence of dimethylselenium. Finally, the deprotected peptide was incubated with dithiothreitol to reduce sulfoxide on the methionine side chain. The increase of the E-rosette-forming lymphocytes was obtained after incubation of peripheral blood from lupus nephritis patients with the synthetic thymosin beta Met9. The synthetic thymosin beta Met9 was approximately equal in potency to that of our synthetic calf thymosin beta 9.     

铸造铝青铜合金Cu-14Al-4Fe-Mn的摩擦磨损性能

用往复式摩擦磨损试验机考察了新型高强度、高耐磨性铸造铝青铜合金Cu-14Al-4Fe-Mn(代号HSWAB)的摩擦磨损性能,利用形貌扫描电子显微镜观察分析了合金磨损表面形貌,探讨了其磨损机理.结果表明,HSWAB合金在干摩擦和油润滑条件下的摩擦磨损性能及磨损机理存在明显差异.在干摩擦条件下,合金中脱落的硬质点及氧化物等磨粒导致较为严重的磨粒磨损,摩擦系数高、磨损率大,主要磨损机理为磨粒磨损、粘着磨损、氧化磨损及疲劳磨损.在油润滑条件下,摩擦系数和磨损率均显著降低,疲劳磨损和氧化磨损受到抑制,主要磨损机理为磨粒磨损和粘着磨损.Cu-14Al-4Fe-Mn合金在油润滑条件下的摩擦系数低达0.08,磨损率低达3.7×10-6g/m,是一种优良的耐磨材料.