Inhibitoren der Korrosion (8) Über die Abhängigkeit der Korrosionsinhibierung des Eisens in Salzsäure von der Struktur quartärer Phosphoniumsalze

Inhibition of the corrosion of iron in hydrochlorid acid as a function of the structure of quaternary phosphonium salts In the case of quaternary phospho-nium salts there is no direct relation between their inhibiting power in deaer-ated acid media and the polarographi-cally determined reduction potentials. The inhibiting effect can in a first line be attributed to sterical factors con-nected with the fragments formed after incorporation of two electrons and be-coming fixed to the iron surface. Biphosphonium salts having saturated or unsaturated bridges are excellent in-hibitors under the conditions mentioned. Most efficient are biphosphonium salts having chaines of 4 to 10 methylene groups between the phosphonium cen-tres. The rigid p-phenylene radikal is less suitable as a linking principle. Phe-nyl phosphine and diphenyl phosphine in low concentrations accelerate corro-sion and exhibit a protective effect only in higher concentrations. Polymers having incorporated phos-phonium centres are only moderate inhibitors when compared to biphospho-nium salts. The synthesis is outlined and some physical and chemical properties are given.     

Inhibitoren der Korrosion 10 (1). Nachweis der Sekundärinhibition durch Allyl-triphenyl-phosphonium- bzw. arsoniumbromid und N-Allyl-chinaldiniumbromid

Corrosion inhibitors (10) Demonstration of the secondary inhibition by allyl triphenyl phosphonium and arsonium bromides and N-ally1 quinaldinium bromide Triphenyl allyl phosphonium (1) and arsonium (2) salts as well as allyl quinaldinium bromide (4) are corrosion inhibitors of moderate efficiency. In acid media they are reduced by carfinyl iron powder to yield triphenyl phosphine and triphenyl arsine respectively and quinaldine. The two products mentioned the first form a layer on carbonyl iron and, after extraction, may be identified by gas chromatography. The allyl group is eliminated by iron from 1, 2 and 4, yielding Pro-pene, propane and, probably, cyclopropane. The hydrocarbon quantities determined by gas chromatography are in good agreement with the values found in the gravimetric determination of allyl-onium salts after the reaction. Ally triphenyl phosphonium bromide ( I ) and allyl diphenyl sulfonium tetraborate (3) yield propene and propane in a 1:1 ratio. In the case of (2) and (4) this ratio is shifted to 14:l and 7:l respectively. The hydrocarbon proportion in the gas mix-ture is higher at the beginning of the reaction than toward its end; at the beginning, the Propane:propene ratio is also displaced, the formation of propane having priority.     

Effects of roscovitine on maintenance of the germinal vesicle in horse oocytes,subsequent nuclear maturation,and cleavage rates after intracytoplasmic sperm injection

This study was conducted to evaluate the effects of roscovitine on suppression of meiosis, subsequent meiotic maturation, and cleavage rates after intracytoplasmic sperm injection of horse oocytes. Oocytes were classified as having compact or expanded cumuli (Com or Exp oocytes) and were divided into three culture groups: 30 h culture in maturation medium (30 h Mat); 54 h culture in maturation medium (54 h Mat), or 24 h culture in medium containing 66 micro mol roscovitine l(-1) and then 30 h culture in maturation medium (Ros+M). After maturation, oocytes were subjected to intracytoplasmic sperm injection and cultured in G1.2 medium for 96 h. Among oocytes fixed immediately after roscovitine culture, 26 of 31 (84%) Com oocytes and 16 of 28 (57%) Exp oocytes were at the germinal vesicle stage (P<0.05). After maturation culture, there were no differences in maturation rates or morphological cleavage rates among treatments. Among Com oocytes, significantly more embryos in the Ros+M treatment than in the 54 h Mat treatment had cleaved with > or = two normal nuclei (63 versus 36%; P<0.05); whereas among Exp oocytes, significantly more embryos in the 30 h Mat treatment than in the Ros+M treatment (63 versus 42%; P<0.05) had cleaved with > or = two normal nuclei. The average number of nuclei in embryos at 96 h was significantly higher (P<0.05) in Ros+M Com oocytes (13.5) than in any other Com or Exp group. These results demonstrate that roscovitine can reversibly maintain equine oocytes in the germinal vesicle stage for up to 24 h, and that such suppression may increase the developmental potential of Com, but not Exp, oocytes.     

Influence of the suspension media on the thermal treatment of mesophilic lactococcal bacteriophages

The thermal resistances of the Lactococcus lactis phages P008 (a heat-sensitive wide-spread phage) and P680 (a heat-resistant phage) suspended in milk and in solutions supplemented with milk components were studied to elucidate the protective role of milk on phage inactivation. For both phages a decrease of inactivation was observed in casein solution. Furthermore, the inactivation kinetics of the phages in whey, in whey cream (3.5%, 20%, 30% fat) and in whey protein concentrate (0.7%, 5%, 10% protein) were tested. The inactivation experiments in whey cream and in whey protein concentrate having different concentrations of fat and protein revealed that fat had no influence on the inactivation, while, in contrast, the presence of protein had a protective effect.     

Structure and electrical conductivity of TCNQ-2,3,7,8-tetramethoxychalcogenanthrene complexes

Charge-transfer complexes formed by reaction of 2,3,7,8-tetramethoxychalcogenanthrenes(5,10-dichalcogenacyclo-diveratrylenes, ‘Vn₂E₂’) with 7,7,8,8-tetracyanoquinodimethane (TCNQ) are prepared and their structures determined. Spin concentration, mobilities and gap energies of the polycrystalline samples are evaluated from e.s.r. intensities and electrical conductivity measurements. The influence of the different chalcogen atoms on physical properties is discussed.     

Cleanability of Surfaces from Active Pharmaceutical Ingredient Surrogate Riboflavin by Falling Film

Falling films in wash down process are of major interest for pharmaceutical isolators, which are used for processing of highly potent pharmaceutical products. In this study multiple process parameters were examined with common materials of isolator systems. The importance of material and surface finish in respect of cleanability and complete wetting as well as a combination of process parameters are presented and discussed. For cleaning validation an effect of high interest was discovered: swab sampling areas changed their properties over many repeated cycles and showed decreased cleanability.     

Comparison of different methods for the recovery of horse oocytes

The object of this study was to compare 4 different methods of oocyte recovery from mares; 1) transvaginal follicle aspiration in vivo; 2) follicle aspiration in vitro; 3) oocyte recovery by isolation of follicles in vitro and 4) follicle scraping in vitro. Oocyte recovery was highest after follicle scraping (71.1%) and follicle isolation and rupture (61.3%). Follicle aspiration in vitro and in vivo yielded oocytes on 31.2% and 19.3% of occasions, respectively. The output of different types of cumulus-oocyte-complexes was different among the methods; the portion of compact cumulus-oocyte-complexes was significantly higher with follicle scraping (50.7%) and follicle isolation (44.5%) than with aspiration in vivo (31.9%) and in vitro (23.7%). The recovery rate of oocytes from small follicles (<15 mm) was significantly higher than from larger follicles (P<0.05) using transvaginal follicle aspiration. The proportion of oocytes that were degenerate (exhibited shrunken, dense or visibly damaged ooplasm) ranged from 1.2% after follicle scraping, to 17.2% after aspiration in vivo. These results indicate that, for the recovery of horse oocytes in vitro, follicle scraping and follicle isolation give the highest recoveries of cumulus-intact oocytes.     

Interactive Volume Rendering with Dynamic Ambient Occlusion and Color Bleeding

We propose a method for rendering volumetric data sets at interactive frame rates while supporting dynamic ambient occlusion as well as an approximation to color bleeding. In contrast to ambient occlusion approaches for polygonal data, techniques for volumetric data sets have to face additional challenges, since by changing rendering parameters, such as the transfer function or the thresholding, the structure of the data set and thus the light interactions may vary drastically. Therefore, during a preprocessing step which is independent of the rendering parameters we capture light interactions for all combinations of structures extractable from a volumetric data set. In order to compute the light interactions between the different structures, we combine this preprocessed information during rendering based on the rendering parameters defined interactively by the user. Thus our method supports interactive exploration of a volumetric data set but still gives the user control over the most important rendering parameters. For instance, if the user alters the transfer function to extract different structures from a volumetric data set the light interactions between the extracted structures are captured in the rendering while still allowing interactive frame rates. Compared to known local illumination models for volume rendering our method does not introduce any substantial rendering overhead and can be integrated easily into existing volume rendering applications. In this paper we will explain our approach, discuss the implications for interactive volume rendering and present the achieved results.     

Relationships among oocyte-cumulus morphology, follicular atresia, initial chromatin configuration, and oocyte meiotic competence in the horse

Horse oocytes with expanded (EX) cumuli appear to have greater meiotic competence than do horse oocytes with compact (CP) cumuli but are thought to come from atretic follicles. We evaluated the relationships among cumulus expansion, follicle viability, initial chromatin configuration, and meiotic competence of horse oocytes. Follicle walls were sectioned for histological examination, and the follicles were scraped to obtain the oocytes. Half of the oocytes were evaluated immediately and half were matured for 24 h in vitro. Cumulus expansion was significantly associated with follicle atresia. Initially, significantly more EX than CP oocytes had chromatin condensed into one mass within the germinal vesicle (CC configuration; 61% vs. 32%). After culture, significantly more EX than CP oocytes had matured (74% vs. 30%). The proportion of oocytes with the CC configuration was lowest in viable follicles and increased in follicles with slight to moderate atresia. The maturation rate of oocytes from viable follicles was significantly lower than for oocytes from follicles with slight or moderate atresia. The CC chromatin configuration appears to be associated with meiotic competence in horse oocytes. The association of follicle atresia with increased meiotic competence suggests that acquisition of meiotic competence is related to a loss of suppressive activity by the degenerating follicle.     

MHC class Ib-restricted cells contribute to antilisterial immunity: evidence for Qa-1b as a key restricting element for Listeria-specific CTLs

Subclinical infection of BALB/c mice with the intracellular pathogen Listeria monocytogenes results in the development of MHC class Ia- and Ib-restricted CTLs. L. monocytogenes-infected TAP-/- bone marrow macrophage targets are not lysed by MHC class Ia- or Ib-restricted CTLs, showing a requirement for transport of peptides into the endoplasmic reticulum for development of the MHC class Ib-peptide target. L. monocytogenes-infected B6.Tla(a)-derived bone marrow macrophages (Kb Qa-1a) are not lysed by BALB/c (Kd Qa-1b)-derived antilisterial CTLs, confirming an earlier finding that the Ib-restricting element is T region encoded. We have further determined that Qa-1b is a restricting element for antilisterial CTLs using L. monocytogenes-infected Qa-1b-transformed mouse L cells as well as human-derived HeLa cells as target populations. These L. monocytogenes-infected Qa-1b-transformed cell lines are lysed by BALB/c (Qa-1b)- or C57BL/6 (Qa-1b)-derived antilisterial CTLs, but are not lysed by B6.AKM (Qa-1a)-derived antilisterial CTLs. Using L. monocytogenes-infected targets, we found that MHC class Ia- and Ib-restricted CTLs are evident within 4 days following infection, peak on day 5 following infection, and although Ib-restricted CTLs disappear by day 6 postinfection, la-restricted antilisterial CTL activity can still be detected. These results demonstrate that Qa-1b is a restricting element for antilisterial CTLs, and expression of the MHC class Ib-presented target at the cell surface is TAP dependent. In addition, these results show that following L. monocytogenes infection, MHC class Ib-restricted CTLs are evident in vivo.