质子传导陶瓷膜在催化脱氢反应中的应用

有机化合物催化脱氢是一种吸热、体积增大的可逆反应过程,通过特定的膜将反应过程中生成的氢气不断地移出反应区,可促使反应向产物方向移动,从而提高反应转化率、减少副反应并最终达到降低反应温度、提高产率的目的。质子传导陶瓷膜可以以质子传递方式选择性透过氢,具有成本低、选择高,耐高温、热稳定及化学稳定性能好、不易中毒等特点,非常适合于脱氢膜反应器。本文对质子传导陶瓷膜材料、透氢机理、膜制备、膜反应器及其用于脱氢反应的研究现状与进展情况进行了综述。     

In vitro comparison of antigraft protection mechanisms in 2 genera of lumbricians: Eisenia and Lumbricus]

We sum up our in vitro experiments on allograft reactions in 2 genera of Lumbricians: Eisenia and Lumbricus. In Eisenia, first this reaction is a non-specific humoral one, then it becomes a specific cellular reaction. In Lumbricus the allograft reaction is a specific, mostly cellular one. Nevertheless it interferes with an acquired, specific humoral reaction.     

Effects of plant lectins on cellular defense reactions of ascidian hemocytes

The effects of plant lectins on the three cellular defense reactions of hemocytes of the solitary ascidian,Halocynthia roretzi (hemocyte aggregation, phagocytosis, and an allogenic reaction), were investigated. Concanavalin A inhibited aggregation, while wheat germ agglutinin and ricin inhibited the allogenic reaction. Neither of the lectins showed inhibitory effects on phagocytosis, but ricin promoted phagocytosis. These effects of the lectins were diminished by the addition of sugars specific for the respective lectins. These results strongly suggest that different surface carbohydrates are involved in the recognition mechanisms of threeH. roretzi cellular defense reactions.     

Zur Reaktionsweise eines Zeisigs (Carduelis spinus (L.)) auf gefilterte Kontaktrufe

Summary The acoustic reactions of siskins (Carduelis spinus L.) were demonstrated by stimulation with their own close-contact call. The calls were modified by low-pass or high-pass filter. Within determinated filter ranges the acoustic reaction rate increases up to 146 respectively 128%. It is suggested that the modified signals act as super-normal stimuli in the acoustic behaviour of the examined species.     

Reversible umsteuerung lichtempfindlicher systeme bei pflanzen und tieren

Summary The reversible red, far-red reaction which controls germination of seeds or spores, and a large number of light-dependent reactions in algae, mosses and ferns, is compared with the reversible ultraviolet-bluegreen reaction, i.e. the chromatic response, of the terminal vesicle of the frog's pineal body (Stieda's organ).     

Gibt es peptisch-tryptische Abbaustufen des Gliadins mit Antigencharakter?

Summary Peptic and tryptic digestion of gluten and gliadin leaves a part of the substrates unaltered after precipitation at pH 4.5. Complement fixation test of the soluble part remains positive even after autoclaving of this part at pH 4.5, but not so after autoclaving at alkaline reaction. Positive reactions are also given by the components which are not ultrafiltrable while the ultrafiltrates give negative reactions. This means that positive reactions originate from residues of gluten or gliadin respectively. The question posed in the title must be answered in the negative. Products of peptic-tryptic digestion of gliadin do not have antigenic properties.     

Zur Spezifität des durch Bradykinin,Kallidin und Met-Kallidin ausgelösten Blutdruckreflexes an der Katze

Summary Synthetic kinins (bradykinin, kallidin and met-kallidin) administered via the femoral artery in the isolated hindlimb of the cat elicits vasoconstriction, a reflex on the systemic blood pressure, a stimulation of respiration, and contraction of nictitating membrane. Acetylcholine elicits these reflex reactions in the body too. Atropine blocks this reflex, but not the reactions of kinins. Phenylbutazone administered via the femoral artery blocks the reflex reactions of acetylcholine and kinins as well as the vasoconstriction of histamine and the kinins in the isolated hindlimb. Phenylbutazone elicits by itself a reflex reaction. Of all the synthetic substances, the kinins are the most specific drugs inducing reflex reactions.     

Chlorophyll breakdown in higher plants and algae

Leaf senescence is accompanied by the metabolism of chlorophyll (Chl) to nonfluorescent catabolites (NCCs). The pathway of Chl degradation comprises several reactions and includes the occurrence of intermediary catabolites. After removal of phytol and the central Mg atom from Chl by chlorophyllase and Mg dechelatase, respectively, the porphyrin macrocycle of pheophorbide (Pheide) a is cleaved. This two-step reaction is catalyzed by Pheide a oxygenase and RCC reductase and yields a primary fluorescent catabolite (pFCC). After hydroxylation and additional species-specific modifications, FCCs are tautomerized nonenzymically to NCCs inside the vacuole. Different subcellular compartments participate in Chl catabolism and, thus, transport processes across membranes are required. This review focuses on the catabolites and the individual reactions of Chl breakdown in higher plants. In addition, the pathway is compared to Chl conversion to red catabolites in an alga, Chlorella protothecoides. Finally, the significance and regulation of Chl degradation are discussed.     

Die Wirkung von synthetischen Antihistaminkörpern auf die Senfölchemosis am Kaninchenauge

Summary Intravenous or subcutaneous administration of pyribenzamine and other antihistaminics is able to decrease, and to delay the appearance of chemosis produced by mustard oils in the eye of the rabbit. Simultaneously occurring vascular reactions, on the other hand, are but slightly affected by antihistaminics. Intravenous or subcutaneous administration of rutin has no clear-cut effect on chemosis; it is however able to inhibit the vascular reaction.     

Possible presence of autoantibodies to zone pellucida in infertile women.

Of 52 serum samples from infertile women tested against isolated porcine oocytes by immunofluorescence, 8 produced intense reactions in zonae pellucidae, while only one of 52 sera from control subjects showed the reaction. Autoantibodies to the zona may be present in these women.     

Shape change of blood platelets induced by myelin basic protein.

Myelin basic protein (MBP) isolated from bovine spinal cord caused a marked shape change reaction of human blood platelets which was not accompanied by the release reaction and not inhibited by methysergide and spiroperidol. Only those basic proteins, including MBP, which had previously shown to exert neuronal depolarisation also induced the shape change reactions. Therefore, these findings may extend the use of platelets as neuronal models.     

Immunologic blood-brain barrier in the polyoma virus--Syrian hamster system]

The authors report premilinary results of an experiment on permeability of the blood-brain barrier (BBB) to anti-tumor virus-induced immunological factors in the polyoma virus/Syrian Hamster system. The animals were protected by subcutaneous or intracranial injections with virus before challenge with polyoma virus transformed cells by both routes. BBB seemed to be permeable to the efferent part of the subcutaneously induced immune reaction. On the contrary, antigenic information introduced in the central nervous system was trapped inside the BBB. Thus the BBB might offer a "one-way" permeability in this system.     

Microbial energetics applied to waste repositories

Summary Through their catalytic abilities microbes can increase rates of chemical reactions which would take a very long time to reach equilibrium under abiotic conditions. Microbes also alter the concentration and composition of chemicals in the environment, thereby creating new conditions for further biological and chemical reactions. Rates of degradation and possible indirect consequences on leaching rates in waste repositories are a function of the presence or absence of microbes and of the conditions which allow them to become catalytically active.Microbially mediated reactions are no exception to the rule that all chemical processes are basically governed by thermodynamic laws. Naturally occurring processes proceed in the direction that leads to the minimal potential energy level attained when equilibrium is reached. A continuous supply of energy to an ecosystem in the form of biochemically unstable compounds maintains non-equilibrium conditions, a prerequisite for all chemotrophic life. Energy is released as a chemical reaction progresses towards equilibrium. Microbes scavenge that portion of the free energy of reaction (G_r) which can be converted into biochemically usable forms during the chemical oxidation processes. As electrontransfer catalysts, the microorganisms mediate reactions which are thermodynamically possible thereby stimulating reaction rates. Decomposition and mineralization in systems without a continuous supply of substrates and oxidants will lead to equilibria with minimal free energy levels at which point further microbial action would cease. The differences in the free energy levels of reactions (G_r), represent the maximal energy which is available to microorganisms for maintenance and growth. How much of the released free energy will be conserved in energy-rich bonds, compounds (e.g. ATP), and chemical potentials (e.g. emf) useful for biosynthesis and biological work is characteristic for the microbes involved and the processes and metabolic routes employed.Materials whose elements are not present in the most oxidized form attainable in the oxic environment of our planet are potentially reactive. Microbial activities are associated only with chemical reactions whose free energy changes are exergonic. This should be kept in mind for all investigations related to the role of microbes in repositories or in the layout of proper waste storage conditions. Rigorous application of thermodynamic concepts to environmental microbiology allows one to develop models and design experiments which are often difficult to conceive of in complex natural systems from physiological information alone. Thermodynamic considerations also aid in selecting proper deposition conditions and in carrying out thoughtful experiments in areas related to microbial ecology of waste repositories.     

Sur l'apogéotropisme du Phycomyces

Summary Under definite conditions of culture, growth of sporangiophore of Phycomyces has been investigated by Shadowgraphic method. During sporange formation, the rate of growth is the smallest (Fig. 1). The apogeotropic sensitivity of sporangiophores is the greatest before sporange formation; presentation and reaction times increase with age and strongly with light pre-treatment (Fig. 2, 3). Auxin could be responsible for apogeotropic reactions of Phycomyces.     

Heavy metal hydrolysis of polyisoprenoid-phosphate mono- and oligosaccarides

Summary Mono- and oligosaccharide derivatives of dolichol phosphate can be hydrolyzed by heavy metal, preferably Zn⁺⁺ at 100°C or 65°C. The reactions follow first order kinetics. The reaction proceeds through hydrolysis of the sugar phosphate bond.This work was supported by GB No. 38335.     

Stereochemistry of enzymic processes in the biosynthesis of pyrrolizidine alkaloids.

The harmonization of biosynthetic pathways with organic reaction mechanisms has relied heavily on stereochemical studies. The field of biosynthesis of pyrrolizidine alkaloids exemplifies these connections through a wide range of common organic reactions including oxidation condensation, and decarboxylation. Further, the applications of biogenetic concepts and enzyme-catalysed reactions to synthesis are illustrated. The results are exciting, not only for their intrinsic scientific interest, but because they point the way to using plant enzymes to recognise structurally modified biosynthetic intermediates and hence open routes to the synthesis of new compounds that would otherwise be difficult to obtain.     

Metabolic and redox signaling in the retina

Visual perception by photoreceptors relies on the interaction of incident photons from light with a derivative of vitamin A that is covalently linked to an opsin molecule located in a special subcellular structure, the photoreceptor outer segment. The photochemical reaction produced by the photon is optimal when the opsin molecule, a seven-transmembrane protein, is embedded in a lipid bilayer of optimal fluidity. This is achieved in vertebrate photoreceptors by a high proportion of lipids made with polyunsaturated fatty acids, which have the detrimental property of being oxidized and damaged by light. Photoreceptors cannot divide, but regenerate their outer segments. This is an enormous energetic challenge that explains why photoreceptors metabolize glucose through aerobic glycolysis, as cancer cells do. Uptaken glucose produces metabolites to renew that outer segment as well as reducing power through the pentose phosphate pathway to protect photoreceptors against oxidative damage.     

Possible presence of autoantibodies to zona pellucida in infertile women

Summary Of 52 serum samples from infertile women tested against isolated porcine oocytes by immunofluorescence, 8 produced intense reactions in zonae pellucidae, while only one of 52 sera from control subjects showed the reaction. Autoantibodies to the zona may be present in these women.This work was supported in part by a grant from WHO Task Force on Immunological Methods for Fertility Regulation Project No. 76464.     

Stereochemistry of enzymic processes in the biosynthesis of pyrrolizidine alkaloids

The harmonization of biosynthetic pathways with organic reaction mechanisms has relied heavily on stereochemical studies. The field of biosynthesis of pyrrolizidine alkaloids exemplifies these connections through a wide range of common organic reactions including oxidation, condensation, and decarboxylation. Further, the applications of biogenetic concepts and enzyme-catalysed reactions to synthesis are illustrated. The results are exciting, not only for their intrinsic scientific interest, but because they point the way to using plant enzymes to recognise structurally modified biosynthetic intermediates and hence open routes to the synthesis of new compounds that would otherwise be difficult to obtain.