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61.
The morphological development and N uptake patterns of spring barley (Hordeum vulgare L.) genotypes of Northern European (Nordic) and Pacific Northwest US (PNW) origin were compared under two diurnally fluctuating root temperature regimes in solution culture. The two regimes, 15/5°C and 9/5°C day maximum/night minimum temperatures, simulated soil temperature differences between tilled vs. heavy-residue, no-till conditions, respectively, observed during early spring in eastern Washington. Previous field experiments indicated that some of the Nordic genotypes accumulated more N and dry matter than the PNW cultivars during early spring under no-till conditions. The objective of this experiment was to determined whether these differences 1) are dependent on the temperature of the rooting environment, and 2) are correlated with genotypic differences in NH4 + and NO3 uptake. Overall, shoot N and dry matter accumulation was reduced by 40% due to lower root temperatures during illumination. Leaf emergence was slowed by 14 to 22%, and tiller production was also inhibited. All genotypes absorbed more ammonium than nitrate from equimolar solutions, and the proportion of total N absorbed as NH4 + was slightly higher in the 9/5°C than the 15/5°C regime. A Finnish genotype, HJA80201, accumulated significantly more shoot N than the PNW cultivars, Clark and Steptoe, and also more than a Swedish cultivar, Pernilla, in the 9/5°C regime. In the 15/5°C regime Steptoe did not differ in shoot N from the Nordic genotypes, while Clark remained significantly lower. These differences were not correlated to relative propensity for N form. Root lengths of the Nordic genotypes were significantly greater than the PNW genotypes grown under the 9/5°C regime, while the root lengths in the warmer root temperture regime were not significantly different among genotypes. Higher root elongation rates under low soil temperature conditions may be an inherent adaptive mechanism of the Nordic genotypes. Overall, the data indicate that lower maximum daytime temperatures of the soil surface layer likely account for a significant portion of the growth reductions and lower N uptake observed in no-till systems.  相似文献   
62.
63.
Protein purification of recombinant proteins constitutes a significant cost of biomanufacturing and various efforts have been directed at developing more efficient purification methods. We describe a protein purification scheme wherein Ralstonia eutropha is used to produce its own “affinity matrix,” thereby eliminating the need for external chromatographic purification steps. This approach is based on the specific interaction of phasin proteins with granules of the intracellular polymer polyhydroxybutyrate (PHB). By creating in-frame fusions of phasins and green fluorescent protein (GFP) as a model protein, we demonstrated that GFP can be efficiently sequestered to the surface of PHB granules. In a second step, we generated a phasin-intein-GFP fusion, wherein the self-cleaving intein can be activated by the addition of thiols. This construct allowed for the controlled binding and release of essentially pure GFP in a single separation step. Finally, pure, active β-galactosidase was obtained in a single step using the above described method.  相似文献   
64.

Background  

A prospective observational study was done to describe nonbacterial pulmonary complications in hospitalized patients with human immunodeficiency virus (HIV) infection.  相似文献   
65.
Differentiation of endocarditic from nonendocarditic Staphylococcus aureus (SA) septicemia is prognostically and therapeutically important. A study of 68 cases of either SA or streptococcal sepsis, including 50 cases of SA sepsis of both cardiac and noncardiac origin, was done to determine the presence and titer of serum teichoic acid antibodies (TAA''s) by double immunodiffusion. Thirty-seven uninfected controls were also examined. There was no statistical difference in either incidence or peak TAA titers in endocardial versus deepseated, extracardiac SA sepsis. However, in both of these groups, incidence and peak titers were significantly higher than in intravascular catheter-related SA sepsis, streptococcal endocarditis and controls (P<0.05). Peak TAA titers in SA sepsis develop on admission or shortly thereafter (6 to 11 days) and permit early decisions on degree of tissue infection, likelihood of metastatic seeding and necessity for higher-dose, longer-term antibiotic therapy.Cases of catheter-related SA sepsis with no clinical evidence of metastatic SA seeding and with negative or low-titered (1:1) TAA''s were classified as superficial sepsis. Treatment consisted of short-term, low-dose antistaphylococcal regimens and catheter removal. In posttherapy follow-up after 6 to 12 weeks, all of the patients were cured and no signs of endocarditis or deepseated SA infection developed.  相似文献   
66.
Summary Morphological alterations induced by dehydroepiandrosterone (DHA) were studied in polycystic mouse ovaries (PCO). Treated mice showed ovulatory failure and cystic changes; cysts and follicles in various stages of growth and atresia were present although corpora lutea were absent. The levels of testosterone, dihydrotestosterone, 3- and 3-androstanediol, estrone and androstenedione increased, whereas estradiol was not detectable.The ultrastructure of granulosa cells in healthy and atretic follicles was similar to that of control animals, although the membrana granulosa in cysts was reduced to a monolayer of flattened cells. The theca interna of healthy and atretic follicles and ovarian cysts showed ultrastructural signs of abnormal steroidogenic stimulation.No significant differences (0.7<P<0.8) were found between the extensive surface area of gap junctions of healthy follicles of control and DHA-treated animals. On the P-face of granulosa cells of large healthy follicles, meandering strands of tight junctional particles were observed; their average length was significantly longer than those in healthy follicles of control animals (P<0.001). This increase was probably related to the large amounts of androgens present in the treated animals.Theca interna cells possessed small gap junctions; no significant differences (P>0.9) in gap-junction surface area were observed between DHA-treated and control animals. These results suggest that the size of gap junctions is probably unrelated to the steroidogenic activities of theca cells.The following trivial names have been used: Dihydrotestosterone: 5-androstan 17 ol-13 one; 3-androstanediol: 5-androstan 3,17 diol; 3-androstanediol: 5-androstan 3,17 diol  相似文献   
67.
1) The activities of 16 enzymes of glycolysis and of glutathione metabolism were determined in intact human red cell membranes (ghosts) which were prepared by hypotonic hemolysis. 2) Enzymes and hemoglobin of the ghosts were resolved by two toluene extractions. Only the four enzymes hexokinase, fructose-bisphosphate aldolase, glyceraldehyde-phosphate dehydrogenase and pyruvate kinase could not be released completely from the ghosts. 3) The residual membrane fraction, which was obtained after the toluene extraction of ghosts prepared at 30 imOsM, contained 0.02% of the original hemoglobin content of the red cell. Between 6.5 and 23% of the hemolysate activities of glyceraldehyde-phosphate dehydrogenase, phosphoglycerate kinase, pyruvate kinase and fructose-bisphosphate aldolase were detected in this fraction after mechanical disruption. 4) Sonication of intact ghosts increased the activities of fructose-bisphosphate aldolase, pyruvate kinase and phosphoglycerate kinase. 5) In "white" ghosts prepared at 5 imOsM phosphate buffer which contained 0.5% of the original hemoglobin the activities of fructose-bisphosphate aldolase and glyceraldehyde-phosphate dehydrogenase were detected at high levels. The activities of pyruvate kinase and phosphoglycerate kinase were low in these preparations. 6) The results indicate that one part of all enzymes is loosely attached to the inner surface of the membrane as is hemoglobin. A second part, the "cryptic enzyme activity", is available after resolving by toluene. A residual part of four enzymes is firmly bound to the membrane. Two of them (fructose-bisphosphate aldolase and glyceraldehyde-phosphate dehydrogenase) are oriented toward the inner surface of the membrane, whereas pyruvate kinase and phosphoglycerate kinase are hidden in the lipid core of the membrane.  相似文献   
68.
Doxorubicin (DOX) is a broad-spectrum anthracycline antibiotic that has cardiotoxicity as a major side effect. One mechanism of this toxicity is believed to involve the reactive oxygen radical species (ROS); these agents likely account for the pathophysiology of DOX-induced cardiomyopathy. Aminoguanidine (AG) is an effective antioxidant and free radical scavenger which has long been known to protect against ROS formation. We investigated the effects of AG on DOX-induced changes in thiobarbituric acid reactive substances (TBARS) and reduced glutathione (GSH) content. The rats were divided into four groups:1) Control; 2) DOX group; injected intraperitoneally (i.p.) with DOX 20 mg/kg in a single dose 3) AG-treated group; injected i.p. in single dose of 20 mg/kg DOX plus 100 mg/kg AG 1 h before the DOX for 3 days, 4) AG group; injected i.p. with AG 100 mg/kg for 3 days. DOX administration to control rats increased TBARS and decreased GSH levels. AG administration before DOX injection caused significant decrease in TBARS and increase in GSH levels in the heart tissue when compared with DOX only. Morphological changes, including severe myocardial fibrosis and inflammatory cell infiltration were clearly observed in the DOX-treated heart. AG reversed the DOX-induced heart damage. Therefore AG could protect the heart tissue against free radical injury. The application of AG during cancer chemotherapy may attenuate tissue damage and improve the therapeutic index of DOX.  相似文献   
69.
Experimental vaccine strategies for cancer immunotherapy   总被引:10,自引:0,他引:10  
Recently, cancer immunotherapy has emerged as a therapeutic option for the management of cancer patients. This is based on the fact that our immune system, once activated, is capable of developing specific immunity against neoplastic but not normal cells. Increasing evidence suggests that cell-mediated immunity, particularly T-cell-mediated immunity, is important for the control of tumor cells. Several experimental vaccine strategies have been developed to enhance cell-mediated immunity against tumors. Some of these tumor vaccines have generated promising results in murine tumor systems. In addition, several phase I/II clinical trials using these vaccine strategies have shown extremely encouraging results in patients. In this review, we will discuss many of these promising cancer vaccine strategies. We will pay particular attention to the strategies employing dendritic cells, the central player for tumor vaccine development.  相似文献   
70.

Purpose

A scalable life cycle inventory (LCI) model of a permanent magnet electrical machine, containing both design and production data, has been established. The purpose is to contribute with new and easy-to-use data for LCA of electric vehicles by providing a scalable mass estimation and manufacturing inventory for a typical electrical automotive traction machine. The aim of this article (part I of two publications) is to present the machine design, the model structure, and an evaluation of the models’ mass estimations.

Methods

Data for design and production of electrical machines has been compiled from books, scientific papers, benchmarking literature, expert interviews, various specifications, factory records, and a factory site visit. For the design part, one small and one large reference machine were constructed in a software tool, which linked the machines’ maximum ability to deliver torque to the mass of its electromagnetically active parts. Additional data for remaining parts was then gathered separately to make the design complete. The two datasets were combined into one model, which calculates the mass of all motor subparts from an input of maximum power and torque. The range of the model is 20–200 kW and 48–477 Nm. The validity of the model was evaluated through comparison with seven permanent magnet electrical traction machines from established brands.

Results and discussion

The LCI model was successfully implemented to calculate the mass content of 20 different materials in the motor. The models’ mass estimations deviate up to 21% from the examples of real motors, which still falls within expectations for a good result, considering a noticeable variability in design, even for the same machine type and similar requirements. The model results form a rough and reasonable median in comparison to the pattern created by all data points. Also, the reference motors were assessed for performance, showing that the electromagnetic efficiency reaches 96–97%.

Conclusions

The LCI model relies on thorough design data collection and fundamental electromagnetic theory. The selected design has a high efficiency, and the motor is suitable for electric propulsion of vehicles. Furthermore, the LCI model generates representative mass estimations when compared with recently published data for electrical traction machines. Hence, for permanent magnet-type machines, the LCI model may be used as a generic component estimation for LCA of electric vehicles, when specific data is lacking.
  相似文献   
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