首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
P Resnitzky  D Danon 《Experientia》1976,32(2):257-259
A quick and simple method for the estimation of lysozyme activity using the Fragiligraph, was described. Diminution of turbidity in a suspension of Micrococcus lysodeikticus produced by the addition of standard lysozyme (hen egg white) or serum sample, was continuously recorded for 5 min by the Fragiligraph. The normal mean serum lysozyme activity value obtained by this method is 6,80 mug/ml +/- 1.85.  相似文献   

2.
Summary The euglobulin fraction necrosin, prepared according toMenkin from pleural exudates of dogs, strongly inhibitsin vitro bacterium phagocytosis by leucocytes obtained from the abdominal cavity of rats. Depending on the concentration, the average effect amounts to 18–35%. Necrosin has a similar effect (21–38%) on the circulating leucocytes of the dog. The euglobulin fraction prepared by the same method from the serum of untreated dogs has but a slight inhibitory effect on leucocyte activity.  相似文献   

3.
Summary Sera from guinea-pigs infected with the protozoan parasiteLeishmania enriettii showed higher hemagglutination (HA) titres for neuraminidase treated human erythrocytes than those of normal guinea-pig sera. This HA activity was associated mostly with the 19S fraction of the immune serum and could be absorbed out with an antigenic fraction of the parasite membrane. Antigenic determinants involved in this HA reaction consisted of, at least, -d-galactosyl or lactosyl residues.  相似文献   

4.
Summary Witelo's Perspectiva, which was printed three times in the sixteenth century, profoundly influenced the science of dioptrics until the Age of Newton. Above all, the optical authors were interested in the so-called Vitellian tables, which Witelo must have copied from the nearly forgotten optical Sermones of Claudius Ptolemy. Research work was often based on these tables. Thus Kepler relied on the Vitellian tables when he invented his law of refraction. Several later authors adopted Kepler's law, not always because they believed it to be true, but because they did not know of any better law. Also Harriot used the Vitellian tables until his own experiments convinced him that Witelo's angles were grossly inaccurate. Unfortunately Harriot kept his results and his sine law for himself and for a few friends. The sine law was not published until 1637, by Descartes, who gave an indirect proof of it. Although this proof consisted in the first correct calculation of both rainbows, accomplished by means of the sine law, the Jesuits Kircher (Ars Magna, 1646) and Schott (Magia Optica, 1656) did not mention the sine law. Marci (Thaumantias, 1648) did not know of it, and Fabri (Synopsis Opticæ, 1667) rejected it. It is true that the sine law was accepted by authors like Maignan (Perspectiva Horaria, 1648) and Grimaldi (Physico-Mathesis, 1665), but since they used the erroneous Vitellian angles for computing the refractive index, they discredited the sine law by inaccurate and even ludicrous results.That even experimental determinations might be unduly biased by the Vitellian angles is evident from the author's graphs of seventeenth century refractive angles. These graphs also show how difficult it was to measure such angles accurately, and how the Jesuit authors of the 1640's adapted their experimental angles to the traditional Vitellian ones. Witelo's famous angles, instead of furthering the progress of dioptrics, delayed it. Their disastrous influence may be traced for nearly thirty years after Descartes had published the correct law of refraction.

Vorgelegt von C. Truesdell  相似文献   

5.
Summary Lysozyme was isolated from the small intestine of mice by combined ion-exchange and molecular sieve chromatography. This lysozyme differs from that isolated from the urine of mice with monocytoma in amino acid composition, and migration rate in cellulose acetate electrophoresis. As intestinal lysozyme originates at least in part from the Paneth cell, our results point towards the existence of isozymes of lysozymes in mice.Acknowledgments. Supported by grant No. 20159 from the Fonds voor Wetenschappelijk Geneeskundig Onderzoek, Brussel, Belgium. We should like to thank Mrs.Parein for skillful technical assistance.  相似文献   

6.
The lysozyme of the marine bilave Tapes japonica (13.8 kDa) is a novel protein. The protein has 46% homology with the destabilase from medicinal leech that has isopeptidase activity. Based on these data, we confirmed hydrolysis activity of T. japonica lysozyme against three substrates: L--Glu-pNA, D--Glu-pNA, and -(-Glu)-L-Lys. The optimal pH of chitinase and isopeptidase activity was 5.0 and 7.0, respectively. The isopeptidase activity was inhibited with serine protease inhibitor, but the lytic and chitinase activities were not. Moreover, only isopeptidase activity is decreased by lyophilization, but lytic and chitinase activities were not. We conclude that T. japonica lysozyme expresses isopeptidase and chitinase activity at different active sites.Received 25 February 2003; received after revision 29 May 2003; accepted 12 June 2003  相似文献   

7.
Summary Plasma dopamine -hydroxylase activity of Japanese monkeys (Macaca fuscata fuscata) increased with age, and the developmental changes were similar to those of human beings. However, the adult level plasma DBH activity of various monkey species was much lower than that of human beings.We thank Dr.K. Nozawa, Dr.O. Takenaka and Mr.T. Shotake (Primate Research Institute, Kyoto University) for their help in collecting monkey blood samples.  相似文献   

8.
Summary Before examining de Moivre's contributions to the science of mathematics, this article reviews the source materials, consisting of the printed works and the correspondence of de Moivre, and constructs his biography from them.The analytical part examines de Moivre's contributions and achievements in the study of equations, series, and the calculus of probability. De Moivre contributed to the continuing development from Viète to Abel and Galois of the theory of solving equations by means of constructing particular equations, the roots of which can be written in the form . He also discovered the reciprocal equations. In the course of this work de Moivre discovered an expression equivalent to (cos +i sin ) n =cos n +i sin n and, following Cotes, he succeeded in expressing the nth roots of unity in trigonometric form.In the theory of series, de Moivre developed a polynomial theorem encom-passing Newton's binomial theorem and, in particular, a theorem of recurrent series useful in the calculus of probability.The demands of the calculus of probability led de Moivre to an approximation for the binomial coefficients for large values of n. The interaction between de Moivre and James Stirling, particularly in regard to the asymptotic series for log (n!), is treated at length. This work supplied the foundation for de Moivre's limit theorem for the binomial distribution.The calculus of probability, which occupied him from 1708 onward, became in time ever more the center of de Moivre's inquiries. Proceeding from contemporary collections of gambling exercises, de Moivre, by introducing an explicit measure of probability for the so-called Laplace experiments, found the beginnings of a theory of probability. De Moivre expanded the classic application of probability calculus to games of chance by addressing himself to the problem of annuities and by adopting Halley's work with its conception of Probability of life. De Moivre was the first to publish a mathematically formulated law for the decrements of life derived from mortality tables.
Abkürzungen a.a.O. am angegebenen Ort = Verweis auf das nach Verfassern alphabetisch geordnete Literaturverzeichnis. Eine vor a.a.O. in runden Klammern angegebene Zahl kennzeichnet die entsprechende Nummer der im Literaturverzeichnis aufgeführten Arbeiten eines Autors. - AC Ars conjectandi = Jakob Bernoulli (4) a.a.O. - AE Acta Eruditorum - a.S. alter Stil47 - BM Bibliotheca Mathematica - DMV Deutsche Mathematiker-Vereinigung - JL Journal Literaire - MA Miscellanea Analytica, London 1730 - n.S. neuer Stil47 - PT Philosophical Transactions of the Royal Society of London - r.F. rekurrente Folge - r.R. rekurrente Reihe - SMA Miscellaneis Analyticis Supplementum, London 1730 - v. veröffentlicht (nur im Briefverzeichnis verwendet) Prof. Dr. Kurt Vogel zum 80. Geburtstag Vorgelegt von J. E. Hofmann  相似文献   

9.
A major cytokinin found in coconut milk was isolted by using the tobacco callus growth-promoting assay as a guide during purification. The structure of the factor was determined to be 14-O-{3-O-[-d-galactopyranosyl-(12)--d--galactopyranosyl-(13)--L-arabinofuranosyl]-4-O-(-L-arabinofuranosyl)--d-galactopyranosyl}-trans-zeatin riboside [G3A2-ZR] by various NMR techniques, including heteronuclear multiple bond connectivity by 2D multiple quantum NMR (HMBC), as well as mass spectroscopy and sugar analysis. The optimum concentration of G3A2-ZR for cytokinin activity in the tobacco callus assay was estimated to be 5×10–6 M, so that G3A2-ZR is one order of magnitude more potent than 1,3-diphenylurea and one order less potent than zeatin riboside. At least 20% of the cytokinin activity of coconut milk could be attributed to G3A2-ZR.  相似文献   

10.
Summary Newton solved what was called afterwards for a short time the directKepler problem (le problème direct): given a curve (e.g. an ellipse) and the center of attraction (e.g. the focus), what is the law of this attraction ifKepler's second law holds?The problème inverse (today: the problème direct) was attacked system-atically only later, first byJacob Hermann, then solved completely byJohann Bernoulli in 1710 and followingBernoulli byPierre Varignon. How didBernoulli solve the problem? What method did he use for this purpose and which of his accomplishments do we still follow today?In the second part various questions connected to the first part are dealt with from the point of view, Conflict and Cooperation, suggested byJ. van Maanen to the participants of the Groningen conference.  相似文献   

11.
Summary The rate of turnover of individual P-compounds, related to the metabolic cycle of some phosphatides, was followedin vivo in the brain of rats a few days old after32P administration. The phosphorylcholine is the precursor of the cytidinediphosphatecholine; this in turn may be the precursor of lecithin. Thel--glyceryl-phosphorylcholine represents the degredation product of lecithin. The specific activity curves of the phosphorylethanolamine and phosphorylse rine are similar to that of the phosphorylcholine; likewise thel--glycerylphos-phorylethanolamine is similar to the activity curve of thel--glycerylphosphorylcholine.  相似文献   

12.
Summary The-d-fucosidase and -l-fucosidase activities of digestive juice ofHelix pomatia have been studied.-d-fucosidase can be separated from-d-galactosidase by heat inactivation.  相似文献   

13.
Summary An i.v. injection of 548 g of killedCorynebacterium parvum into C57B1 mice leads to significant changes in serum lysozyme (muramidase) levels. After an initial fall at 24 h, the activity of the enzyme increased progressively, reached a peak on the 9th day and returned to control range after the 15th day.  相似文献   

14.
Summary Anastácio da Cunha's definition of convergent series (Principios Mathematicos, Lisboa 1790, p. 106) was analysed by the Portuguese mathematician J. Vicente Gonçalves (Análise do Livro VIII dos Principios Mathematicos de José Anastácio da Cunha, Congresso do Mundo Português Vol. XII, Tomo I, Lisboa 1940, 123–140) and more recently by the historian A. P. Youschkevitch (J. A. da Cunha et les fondements de l'analyse infinitésimale Revue d'Histoire des Sciences Tomme XXVI, N. 1, 1973, 9–22). This latter author contests Gonçalves' claim to the effect that Cunha anticipated in his definition the well known criteria of convergence commonly attributed to A. Cauchy. However, Youschkevitch's otherwise deeper analysis is based primarily on a French translation of Principios published in Bordeaux in 1811. In this paper, that translation is shown to be misleading at crucial places. Cunha's definition is further analysed, and an interpretation in terms of the potential infinity is proposed which results in a redress of Cunha's originality in this matter.  相似文献   

15.
Summary Specific antiserum againstRana esculenta lens pre- crystallin was prepared in a rabbit by injecting antigen-antibody precipitate of this crystallin obtained from immunoelectrophoresis ofesculenta total soluble lens proteins against homologous antiserum.Acknowledgments. We thank Mr.A. Wachter for the excellent technical help, Mr.Th. Hulskes and Mr.A. M. v. Egeraat for the illustrations and finally Dr.W. E. Hawkins for valuable discussion.  相似文献   

16.
Summary The method used previously for determination of the structure of native poly-d-glutamic acid was extended in modified form (paper chromatography) to thep-aminobenzoyl polypeptide of yeast. It was found that this polypeptide is built up of-glutamyl bonds.  相似文献   

17.
Summary The reduction of the myelin sheath during the Wallerian degeneration is not delayed in C3H/An mice with reduced activity of-d-glucuronidase. After section of the sciatic nerve, an increase of glucuronidase activity in Schwann's cells and macrophages can be shown here too.  相似文献   

18.
Summary The air stores carried by a number of aquatic insects have: a) a hydrostatic function (Brocher, Oortwijn-Botjes, Thorpe, andCrisp); b) the function of an oxygen store (Ege, de Ruiter et al.) and c) the function of a physical gill (Strauss-Durckheim, Ege, etc.). The fact that oxygen is taken up from water with the aid of an air bubble was demonstrated forNotonecta by comparing the life time of insects with and without physical gill (while replenishing the oxygen store from the air was prevented) byEge, and forCorixa byPopham, whileVlasblom determined the oxygen uptake from water with and without air bubble forNotonecta, Naucoris, Corixa, Sigara andNepa. Nepa andSigara can take up considerable quantities of oxygen by cutaneous respiration.During the summer, the gill function of the air store ofNotonecta andNaucoris is of importance only when a water current passes along the animal, caused by ventilation movements of the legs (de Ruiter et al.). At low temperatures, however, the metabolic rate is so low that in many instances the physical gill provides the oxygen required without ventilation movements.An apparatus for the simultaneous determination of oxygen uptake from air and water (Wolvekamp andVlasblom) gave results that provided a means of evaluating the importance of the physical gill function.In some cases, the air store, although in direct contact with the water, does not need to be replenished. InAphelocheirus andElmis, the negative pressure in the bubble, caused by oxygen consumption and the diffusing out of part of the nitrogen, is compensated for by the mechanical resistance of a feltwork of thin hairs and the surface tension of the boundary layer of the water (Thorpe andCrisp). In the African beetle,Potamodytes, the unprotected air bubble is permanent because the strong river currents produce a lowered pressure around the animal according toBernoulli's principle (Stride).  相似文献   

19.
Summary A new synthesis is described of a crystalline 7-methyl-doisynolic acid showing a strong estrogenic activity. This acid is probably identical with the stereoisomer C ofAnner andMiescher. Demethylation of this methoxyacid yields a new doisynolic acid of mp. 113–117° (hemihydrate).

XIII. MitteilungSynthetische Versuche in der Gruppe der östrogenen Hormone; XII. Mitteilung siehe Chem. listy50, 2004 (1956).  相似文献   

20.
Summary Many historians of science recognize that the outcome of the celebrated debate on Boltzmann's H-Theorem, which took place in the weekly scientific journal Nature, beginning at the end of 1894 and continuing throughout most of 1895, was the recognition of the statistical hypothesis in the proof of the theorem. This hypothesis is the Stosszahlansatz or hypothesis about the number of collisions. During the debate, the Stosszahlansatz was identified with another statistical hypothesis, which appeared in Proposition II of Maxwell's 1860 paper; Burbury called it Condition A. Later in the debate, Bryan gave a clear formulation of the Stosszahlansatz. However, the two hypotheses are prima facie different. Burbury interchanged them without justification or even warning his readers. This point deserves clarification, since it touches upon subtle questions related to the foundation of the theory of heat. A careful reading of the arguments presented by Burbury and Bryan in their various invocations of both hypotheses can clarify this technical point. The Stosszahlansatz can be understood in terms of geometrical invariances of the problem of a collision between two spheres. A byproduct of my analysis is a clarification of the debate itself, which is apparently obscure.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号