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21.
A novel concept for performing stoichiometric and catalytic chemical transformations has been developed that is based on the limited miscibility of partially or fully fluorinated compounds with nonfluorinated compounds. A fluorous biphase system (FBS) consists of a fluorous phase containing a dissolved reagent or catalyst and another phase, which could be any common organic or nonorganic solvent with limited or no solubility in the fluorous phase. The fluorous phase is defined as the fluorocarbon (mostly perfluorinated alkanes, ethers, and tertiary amines)-rich phase of a biphase system. An FBS compatible reagent or catalyst contains enough fluorous moieties that it will be soluble only or preferentially in the fluorous phase. The most effective fluorous moieties are linear or branched perfluoroalkyl chains with high carbon number; they may also contain heteroatoms. The chemical transformation may occur either in the fluorous phase or at the interface of the two phases. The application of FBS has been demonstrated for the extraction of rhodium from toluene and for the hydroformylation of olefins. The ability to separate a catalyst or a reagent from the products completely at mild conditions could lead to industrial application of homogeneous catalysts or reagents and to the development of more environmentally benign processes. 相似文献
22.
23.
Z Zdárská 《Folia parasitologica》1979,26(3):259-263
The cercariae of Eurytrema pancreaticum (Janson, 1889) possess four types of gland cells - proper cystogenic, penetration, ventral and dorsal gland cells. The secretion of ventral and dorsal gland cells is released into the tegument. The proper cystogenic gland cells are the largest and their contents serve for the formation of the cyst wall of metacercariae in the second intermediate host. The secretion of proper cystogenic gland cells contains besides neutral mucosubstances also acid mucosubstances with both carboxyl- and sulphogroups digestible with beta-glucuronidase. The secretion of penetration gland cells contains neutral mucosubstances and proteins with tyrosine, tryptophan and SS groups. The ventral gland cells contain mostly acid mucosubstances with sulphogroups, which are digested with beta-glucuronidase, and proteins with tyrosine, tryptophan and SH groups. The rudimentary dorsal gland cells contain a small amount of acid mucosubstances. The whole tegument of cercariae and the two main collecting canals of the excretory system exhibit a high alkaline phosphatase activity. The nerve ring and the main nerve truncs contain proteins with SH groups and hydrophilic lipids and exhibit a cholinesterase activity. The suckers contain a larger amount of glycogen. 相似文献
24.
The tissue reaction to Cysticercus bovis in the lung of cattle with an experimental infection was an inflammatory rim originating in the immediate vicinity of the cysts. The cysts recovered at days 83 and 102 p.i. contained living cysticerci. The rim was composed either of a layer of high histiocytes organized in palisades (at day 83 p.i.), or a lyer of flat histiocytes (at day 102 p.i.). The outer layer of the rim consisted of fibroblasts, reticular cells and a different number of eosinophil- and neutrophil luekocytes. On the periphery, the rim was formed by granulation tissue infiltrated with lymphoplasmocytes. At the border between the layers of the inflammatory rim there were conspicuous foci of a necrotic appearance typical of a tissue reaction to C. bovis. 相似文献
25.
The effect of a decrease (and/or fermentation) in the lactose content during milk storage under different conditions was investigated on the accuracy of the results obtained on a Milko-Scan apparatus to contribute to the present knowledge of this problem. The results were in agreement with some results cited in the literature. These wavelengths are used for infrared spectrophotometry on the above apparatus: for fat 3.48 microns, for proteins 6.46 microns and for lactose 9.60 microns. Bulk milk samples used for the tests were untreated or treated with potassium dichromate, bronopol, sodium azide and Milkofix at the temperatures of storage in darkness 20 degrees C and 4 degrees C. The differences against the reference values (measured on the first day) were determined and evaluated in milk composition and characteristics as arising during milk storage. These differences were used in form of either cumulative means of differences (Figs. 1 to 5) or individual differences (Fig. 8). In the first part significant correlation coefficients (P less than 0.001) were calculated for the relationship between the variations of lactose content and the fat and protein contents: r = -0.59 and/or -0.73 (Figs. 6 and 7). This suggests that the decrease in the lactose content by 0.10% recorded by the infrared analysis and caused by lactose decomposition is accompanied by a "seeming" increase in the fat and protein content by about 0.04%. In the second part the correlation coefficients for the fat and protein contents r = -0.96 and -0.96 (P less than 0.001; Figs. 9 and 10; Tab. II) were calculated on the basis of an observation of the lactose decrease in an untreated milk sample (20 degrees C for 28 hours). These coefficients are somewhat different from the preceding ones; this is due to the lower homogeneity of the first set where the milk samples were treated in a different way, but the coefficients confirm the same conclusions. The values of the correlation coefficients for the dependence between the development of the acquired titratable acidity (SH) and the variations of fat (F), protein (P) and lactose (L) contents were as follows: r = 0.95; 0.95; -0.99 (P less than 0.001; Figs. 12, 13; Tab. II). Thus the above-mentioned "seeming" increase in the F and P contents can be explained to the extent of 92.2% from the decrease in the L content, which also causes the increase in titratable acidity to the extent of 98.0%.(ABSTRACT TRUNCATED AT 400 WORDS) 相似文献
26.
V Danielová D Málková J Minár B Rehse-Küpper Z Hájková J Halgos L Jedlicka 《Folia parasitologica》1978,25(2):187-190
In the years 1973 and 1975 mosquitoes and some other Diptera (Tabanidae, Simuliidae, Hippoboscidae) were tested for virus. 13,924 mosquitoes, 75 horseflies and 60 blackflies were processed in 1973. Five strains of Tahyna virus were isolated from mosquito species Aedes vexans. 3,378 mosquitoes and 12 sheep keds were tested for virus in 1975. Twelve strains of Calovo virus were isolated from Anopheles maculipennis and one strain of Tahyna virus was obtained from Aedes vexans mosquitoes. 相似文献
27.
Bacillary rickettsia-like organisms (BRLO) were found in the tick Dermacentor marginatus. They are gram-negative and differ from common bacteria and reckettsiae both in the cultivation conditions and morphology. BRLO are non-pathogenic for ticks and guinea pigs. In our studies they were isolated on half-engorged females of D. marginatus, on which they are still maintained. 相似文献
28.
Of 62 strains of Staphylococcus aureus, isolated from milk samples of dairy-cows with staphylococcic mastitis from five agricultural enterprises, 68 p. c. could be typified as bacteriophages. In 42 typified strains, altogether 17 different phage pictures were found, in which case, in the different agricultural enterprises, the number of phage picture fluctuated between 1 and 8. Phage picture 42 D was found and dominated in all the agricultural enterprises. Of the typified strains, 76% could be ranked only into one phage group and 24% in the "M" group (= miscellaneous). Of 32 typified strains, 56.3% belonged to phage group IV, 25% to group III, 12.5% to group I, and 6.2% to group II. 相似文献
29.
Z Hubálek 《Folia parasitologica》1975,22(1):73-79
Samples of pigeon droppings were taken from 7 sites in a church tower contaminated with C. neoformans, and the distribution patterns of the fungus were studied. From various sites, 0 to 3 x 10(5) viable C. neoformans particles were recovered per one gram of dry excreta. The factors causing the different density of C. neoformans population in the habitat were: uric acid share of the total nitrogen, creatinine content, sunlight and probably pH. Chemical composition of the substrate is the primary factor in the distribution of C. neoformans in droppings. 相似文献
30.
The effect of true milk use in the diet of Spanish Brown Swiss male calves on animal performance, carcass and meat quality, and fatty acids composition was studied. In experiment 1, the effect of milk intake [ad libitum continuous (ADLIB) feed vs. restricted 0.7 during 75 days followed by ad libitum feed (RESTR)] and slaughter endpoint (225 kg vs. 5 month) were studied. In experiment 2, ad libitum concentrate feeding [grain-fed (GF)] was compared with milk supplementation until slaughter [milk-fed (MF)] in calves slaughtered at 345 kg. As regards to milk intake, carcass weight and degree of fatness were higher in the ADLIB group (P<0.05). The RESTR group revealed a higher percentage of saturated fatty acids (P<0.05). In experiment 2, the MF group exhibited a higher fat percentage (P<0.05), lower press and cooking losses (P<0.05), and higher scores for tenderness and juiciness (P<0.05) than the GF group. The percentage of saturated fatty acids was higher in the MF group (P<0.05). The results suggest that true milk use in veal production could be an advantageous alternative in terms on production costs, animal performance, and carcass and meat quality. 相似文献