Effect of 15(R)-15-methyl-prostaglandin E2 on iron absorption in the rat

Summary The administration of 15(R)-15-methyl prostaglandin E₂ (15(R)-15-M-PGE₂) in vivo significantly diminished the uptake of⁵⁹Fe into blood, spleen, liver, femur and dried intestine of rats, whereas acetylsalicylic acid (ASA) increased the counts significantly. This effect of ASA was counteracted by 15(R)-15-M-PGE₂. It is suggested that prostaglandins (PGs) might play an important role in inhibiting iron absorption at the intestinal level.This work was supported by grant No.6638 from CONICET (Argentina). The technical assistance of Mrs María E. Castro and Norma Rizzo is gratefully acknowleged.     

砜基碳负离子的选择性环合反应

比较1，1－双（2－叔丁基砜乙基）十二烷基苯基砜（1）双碳负离子在不同条件下的环合反应结果，控制反应条件，在铁催化下可以生成偶联糁烯化的环烯产物（2）为主要产物；不加催化剂，加热回流反应得到分子内亲核取代反应产物环丙烷化合物（3）。     

The Study of the Grit-blasting Parameters and Their Effects on the Adhesive Strength of the Plasma Sprayed Coatings

Surface Preparation is very important in adhesive b on ding of spray coatings to the surface of a work piece. The common practice is gr it-blasting of the surface before subjecting it to the spray coating process. In this study, grit-blasting of an AISI 4130 steel (of different heat treatmen ts) with Al 2O 3 particles was studied. Various grit-blasting parameters such as blasting particle size, the distance between blasting nozzle and the work pi ece (25, 30 and 40 cm.), blasting pressure (3,4,5,6 and ...     

Pragmatism in Economic Methodology: The Duhem-Quine Thesis Revisited

Contemporary developments in economicmethodology have produced a vibrant agenda ofcompeting positions. These include, amongothers, constructivism, critical realism andrhetoric, with each contributing to the Realistvs. Pragmatism debate in the philosophies of thesocial sciences. A major development in theneo-pragmatist contribution to economicmethodology has been Quine's pragmatic assaulton the dogmas of empiricism, which are nowclearly acknowledged within contemporaryeconomic methodology. This assault isencapsulated in the celebrated Duhem-Quinethesis, which according to a number ofcontemporary leading philosophers of economics,poses a particularly serious methodologicalproblem for economics. This problem, asreflected in Hausman's analysis, consists ofthe inability of economics to learn fromexperience, thereby subverting the capacity totest economic theories. In this paper wedispute this position. Our argument is basedon a combination of Quine's holism with VanFraassen's constructive empiricism, especiallythe latter's analysis of empirical adequacy andhis pragmatic approach to explanation. Theresulting reorientation of economic methodologyrestores the capacity of economics to learnfrom experience and reinstates the imperativeof developing alternatives to orthodoxtheorizing in economics.     

Sound communication inNezara viridula (L.) (Heteroptera: Pentatomidae): Further evidence that signal transmission is substrate-borne

We investigated the sound communication associated with mating inNezara viridula (L.) to clarify conflicting reports on the medium through which acoustic signals are borne. Recordings made from virgin pairs ofN. viridula during precopulatory and compulatory behaviour have revealed that signals transmitted as vibrations through the substrate are a more likely means of communication than signals transmitted by a radiation of sound pressure waves through the air (at least in Australian populations). We present evidence (additional to that already in the literature) that air-borne acoustics are an unlikely mechanism of sexual communication in this species. Specifically, the recorded pulse train patterns showed no consistency or repeatability in relation to different stages of mating behaviour. In contrast, frequency spectrograms of substrate-borne signals reveal repeatable patterns that do correspond with the stage of mating behaviour.     

MeV Pb离子在非晶Si中的射程离散──离子束混合和增强扩散的影响

１．０ＭｅＶ２０８Ｐｂ离子在非晶Ｓｉ中的投影射程ＲＰ和射程偏差ΔＲＰ作为注量和温度二者的函数用背散射法进行测定．注量的变化范围为５×１０１３～７×１０１４ｃｍ－２．注入是在室温和ｔ＝－１２０℃下完成的．由由实验所确定的投影射程，射程偏差与注量或温度无关，并且分别等于２９５和７２．２ｎｍ．与ＴＲＩＭ８６的计算结果相比较，发现ＲＰ的偏离为１８％，而ΔＲＰ的偏离为３６％．ＲＰ和ΔＲＰ二者与注量及温度的无关性，排除了所观察到的与ＴＲＩＭ的矛盾是由于注入期间辐射增强扩散或离子束混合效应而引起的解释。     

Aspirin-like drugs may block pain independently of prostaglandin synthesis inhibition

Summary Using flurbiprofen, a chiral anti-inflammatory and analgesic 2-arylpropionic acid derivative, the enantiomers of which are not converted to each other (less than 5%) in rats or man, we obtained evidence that prostaglandin synthesis inhibition is primarily mediating the anti-inflammatory activity but prostaglandin synthesis independent mechanisms contribute to the analgesic effects. Thus, the S-form inhibited prostaglandin synthesis, inflammation and nociception in rats. The R-form had much less effect on prostaglandin synthesis and did not affect inflammation. It did, however, block nociception in rats almost as potently as the S-form. S-flurbiprofen, in contrast to the R-form, was clearly ulcerogenic in the gastrointestinal mucosa. These results indicate additional molecular mechanisms of analgesia and suggest the use of R-arylpropionic acids as analgesics.