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641.
The magnetic behavior of a binary salt of tricaprylylmethylammonium tetrachloroferrate and tricaprylylmethylammonium chloride, [A336][FeCl4]0.73[Cl]0.27, was evaluated. With a magnetic susceptibility of 0.011 emu mol? 1 this binary salt exhibited a remarkable response to an external magnetic field. Dynamic light scattering (DLS) measurements allowed to study the aggregation behavior of [A336][FeCl4]0.73[Cl]0.27 as well as of further magnetic ionic liquids [PR6,6,6,14][FeCl4] and (BMIM)[FeCl4] in ethylacetate and ethanol.  相似文献   
642.
The activity of rosemary phenolic extracts against Listeria monocytogenes and Escherichia coli was evaluated in 50% food models of meat, vegetable and dairy products in relation to some factors that can affect MIC (minimal inhibitory concentration) values (inoculum level, proportion of food, temperature) using a new food microdilution method. It was shown that the interactions of meat and milk components with plant extracts reduced the antibacterial effectiveness of rosemary extracts. MIC values for L. monocytogenes were lower than for E. coli in all tested conditions. A lower inoculation level caused a decrease in MIC values for E. coli but an increase in MIC values for L. monocytogenes in control media. In food models, MIC values were higher or equal to MIC values in control media regardless of bacterial type. We showed that the food microdilution method represents a simple, rapid, reproducible and inexpensive method for testing the antimicrobial efficiency of plant extracts in food systems.  相似文献   
643.
Victim of its own success, the current Internet is facing scalability issues that lead the research community to explore alternative architectures. In particular, the Locator/ID Split paradigm, based on the idea of separating the identity from the location of end-systems, is gaining momentum and seems to be the most promising candidate for the future Internet architecture. A critical component of any Locator/ID Split approach, from a performance and resources consumption perspective, as well as from a security point of view, is the cache. The cache is meant to temporarily store mappings, i.e., the bindings between identifiers and locations, in order to provide routers with the knowledge of where to forward packets.Taking as reference protocol LISP (Locator/ID Separation Protocol), the most successful proposal currently under discussion at the IETF, this paper presents a thorough analysis of such a component, including the implications of policies to increase the level of security, based on real packet-level traces. Our results prove that even a timeout as short as 60 s provides a high hit ratio and that the impact of using security policies is small. Furthermore, a thorough analysis of the scalability of such a component is provided along with the analysis of which class of applications contributes the major fraction of cache-misses.  相似文献   
644.
The antioxidant activity of Trolox was investigated in emulsions containing different emulsifiers, and decreased in the order Brij 58 > CTAB > SDS. Two degradation products were isolated and identified as Trolox quinone and a keto-derivative. In addition to the stability of Trolox, the effects of the degradation products on lipid oxidation were investigated. In emulsions with SDS, the quinone and the keto-derivative contributed to the overall pro-oxidant effect of Trolox, whereas they had no effect in emulsions containing CTAB or Brij 58. It was concluded that the microenvironment at the o/w interface has a marked influence on the antioxidant and pro-oxidant effects of Trolox and its degradation products via molecular interactions and by affecting its molecular mobility.  相似文献   
645.
Direct inkjet printing (DIP) allows the production of small ceramic specimens with special geometries starting from high solids content suspensions. In this work, thin (300 μm thickness) 3Y-TZP specimens were produced with the DIP technique as model materials for microelectronic applications. The mechanical strength of the printed specimens was evaluated under biaxial loading, and the results were interpreted within the framework of the Weibull theory. Hot-pressed 3Y-TZP specimens with the same geometry and dimensions were tested for comparison. The fracture surfaces were subsequently examined using scanning electron microscopy (SEM). The inkjet printed materials revealed high mechanical reliability (m  10 for σ0  1400 MPa), which was ascribed to the uniform and defect free microstructure generated by the DIP technique.  相似文献   
646.
Das Social Web er?ffnet zahlreiche Chancen für die pers?nliche Entwicklung. Es birgt aber auch Risiken, deren Relevanz von jedem m?glichst früh erkannt werden muss. Erfahrungen in der universit?ren Lehre zeigen, dass Awareness nur durch partizipative und permanente Auseinandersetzung mit der Thematik erreicht werden kann.  相似文献   
647.
Organotin compounds (OTCs) leaching from the antifouling paints used in boats and ships have contaminated many water areas worldwide. The purpose of this study was to obtain a general view of the organotin contamination in fish in Finnish lake areas and Finnish coast of the Baltic Sea using perch as the main indicator species. Perch sampling covered areas presumed as less contaminated and areas suspected as more contaminated. Besides perch, 12 other species were sampled from sites presumed as less contaminated. OTCs measured were mono-, di- and tributyltin, mono-, di-, and triphenyltin and dioctyltin. The sum concentration of OTCs (ΣOTCs) in perch in the least contaminated areas of the Baltic Sea were around 20 ng/g fresh weight (fw) and less than 10 ng/g fw in lake areas. In heavily contaminated areas of the Baltic Sea 150-500 ng/g fw in perch were detected. In lake areas the maximum ΣOTCs in perch was only 30 ng/g fw. With regard to the other species in the Baltic Sea, salmon, sprat, flounder, whitefish, vendace and lamprey contained low concentrations (ΣOTCs mainly less than 20 ng/g fw), whereas in pike, pike-perch, burbot and bream concentrations were higher. ΣOTCs in lake fish were generally lower than in the Baltic Sea. In a distance gradient study, ΣOTCs in perch decreased quickly from nearly 200 ng/g fw at a contaminated harbor area to 35 ng/g fw during a distance of 5 km. Further decrease was slower and reached 15 ng/g fw at 100 km. In a size dependence study triphenyltin showed better correlation with the fish length than tributyltin for all species studied, i.e. for perch (0.16 vs 0.26), pike-perch (0.13 vs 0.24) and roach (0.46 vs 0.80). High correlation for roach may be partly explained by smaller number of samples collected and small length range.  相似文献   
648.
Impact of ambient conditions on SMP elimination and rejection in MBRs   总被引:4,自引:0,他引:4  
The widespread application of the membrane-assisted activated sludge process is restricted by membrane fouling, which increases investment and operating costs. Soluble microbial products (SMPs) are currently considered as the major cause of membrane fouling in membrane bioreactors (MBRs). This study aims at elucidating and quantifying the effects of varying environmental conditions on SMP elimination and rejection based on findings in a pilot MBR and in well-defined lab trials. Several factors are thought to influence the concentration of SMP and their fouling propensity in one way or the other, but findings are often inconsistent or even contradictory. Here, SMP loading rate was found to have the greatest effect on SMP elimination and thus on concentration in the MBR. The degree of elimination decreased at very low DO and low nitrate concentrations. On average, 75% of influent SMP were eliminated in both pilot and lab trials, with the elimination of polysaccharides (PS) mostly above 80%. Rejection of SMP components by the used membrane (PAN, 37nm) ranged mainly from 20% to 70% for proteins and from 75% to 100% for PS. Especially protein rejection decreased at higher temperatures and higher nitrification activity. The increased fouling rates at lower temperatures might therefore partly be explained by this increased rejection. Apparently, mainly the nitrite-oxidising community is responsible for the formation for smaller SMP molecules that can pass the membrane.  相似文献   
649.
Calcium-dependent protein kinases(CDPKs)comprise a family of plant serine/threonine protein kinases in which the calcium sensing domain and the kinase effector domain are combined within one molecule.So far,a biological function in abiotic stress signaling has only been reported for few CDPK isoforms,whereas the underlying biochemical mechanism for these CDPKs is still mainly unknown.Here,we show that CPK21 from Arabidopsis thaliana is biochemically activated in vivo in response to hyperosmotic stress.Loss-of-function seedlings of cpk21 are more tolerant to hyperosmotic stress and mutant plants show increased stress responses with respect to marker gene expression and metabolite accumulation.In transgenic Arabidopsis complementation lines in the cpk21 mutant background,in which either CPK21 wildtype,or a full-length enzyme variant carrying an amino-acid substitution were stably expressed,stress responsitivity was restored by CPK21 but not with the kinase inactive variant.The biochemical characterization of in planta synthesized and purified CPK21 protein revealed that within the calcium-binding domain,N-terminal EF1- and EF2-motifs compared to C-terminal EF3- and EF4-motifs differ in their contribution to calcium-regulated kinase activity,suggesting a crucial role for the N-terminal EF-hand pair.Our data provide evidence for CPK21 contributing in abiotic stress signaling and suggest that the N-terminal EF-hand pair is a calcium-sensing determinant controlling specificity of CPK21 function.  相似文献   
650.
In vivo optical Imaging is an inexpensive and highly sensitive modality to investigate and follow up diseases like breast cancer. However, fluorescence labels and specific tracers are still works in progress to bring this promising modality into the clinical day-to-day use. In this study an anti-MUC-1 binding single-chain antibody fragment was screened, produced and afterwards labeled with newly designed and surface modified NaYF(4):Yb,Er upconversion nanoparticles as fluorescence reporter constructs. The MUC-1 binding of the conjugate was examined in vitro and in vivo using modified state-of-the-art small animal Imaging equipment. Binding of the newly generated upconversion nanoparticle based probe to MUC-1 positive cells was clearly shown via laser scanning microscopy and in an initial proof of principal small animal optical imaging approach.  相似文献   
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