Central chemoreceptor stimulus in the terrestrial,pulmonate snail,Helix aspersa

We studied the effect of hypercapnic and fixed acid central chemoreceptor stimulation on the pneumostone in the pulmonate snail, Helix aspersa. We found that focal stimulation of the central chemoreceptor area of the pulmonate snail brain with hypercapnic solutions more effectively increased the pneumostonal area than did fixed acid stimulation at the same extracellular pH. Disrupting intracellular pH regulation by inhibiting Cl⁻ transport, either pharmacologically (DIDS) or by ion substitution (Cl⁻-free perfusate), enhanced pneumostomal responses to CO₂. While maintaining a constant perfusate pH, addition of NH₄Cl to the perfusate resulted in pneumostomal closure; whereas removal of NH₄Cl from the bath resulted in pneumostomal opening. In conclusion, the ventilatory response to CO₂ in H. aspersa does not require Cl⁻ transport or conductance. Furthermore, changing pH_i alone is an adequate stimulus for the central chemoreceptors in the snail.     

Syntheses of Nα-(β-naphthylsulfonylaminoglycyl)-argininamides as potential selective synthetic thrombin inhibitors

This paper deals with the synthesis of N^α-(β-naphthylsulfonylaminoglycyl)-argininamide compounds and the results of a pharmacological study (in vitro and in vivo). No thrombin inhibition was obtained with N^α-arylsulfonyl-aminoalkyl-(4-amidinophenyl)-alaninamide compounds in which the 4-amidinophenylalanyl residue was substituted by an arginyl residue.     

从高校形象塑造谈地方高校门户网站建设

高校门户网站集中展现了各种校内资源,反映高校的校园文化特色,能及时反映学校的重大事件,对内起到凝聚人心、团结一致的作用。对外它是高校宣传的窗口,是学校在网络交流中的名片,是高校形象塑造的重要网络载体。     

The absolute stereochemistry of protoxylogranatin A – a new protolimonoid from the seeds of Chinese mangrove Xylocarpus granatum

A new protolimonoid, named protoxylogranatin A, has been isolated from the seeds of a Chinese mangrove Xylocarpus granatum. Its structure was elucidated on the basis of modern spectroscopic data. The absolute configuration was determined by the application of the modified Mosher MTPA ester method. The first complete assignments of ¹H and ¹³C NMR spectral data for this protolimonoid were achieved by means of 2D NMR techniques, including ¹H–¹H COSY, HSQC, HMBC and NOESY spectra.     

一次性医疗用品处理与管理的现状和对策

一次性医疗废物较之于普通垃圾危害性更加严重，对其管理和处理直接关系到医患者的安全。因此，加强对一次性医疗用品的处理和管理非常重要。本文综述分析一次性医疗用品存在的问题，提出“从摇篮到坟墓”（cradle to grave）的管理对策，并指出高温热解法更适合于一次性医疗用品的处理。