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81.
Wagner K Janousek J Delaubert V Zou H Harb C Treps N Morizur JF Lam PK Bachor HA 《Science (New York, N.Y.)》2008,321(5888):541-543
Position and momentum were the first pair of conjugate observables explicitly used to illustrate the intricacy of quantum mechanics. We have extended position and momentum entanglement to bright optical beams. Applications in optical metrology and interferometry require the continuous measurement of laser beams, with the accuracy fundamentally limited by the uncertainty principle. Techniques based on spatial entanglement of the beams could overcome this limit, and high-quality entanglement is required. We report a value of 0.51 for inseparability and 0.62 for the Einstein-Podolsky-Rosen criterion, both normalized to a classical limit of 1. These results are a conclusive optical demonstration of macroscopic position and momentum quantum entanglement and also confirm that the resources for spatial multimode protocols are available. 相似文献
82.
An oncogene-induced DNA damage model for cancer development 总被引:6,自引:0,他引:6
Of all types of DNA damage, DNA double-strand breaks (DSBs) pose the greatest challenge to cells. One might have, therefore, anticipated that a sizable number of DNA DSBs would be incompatible with cell proliferation. Yet recent experimental findings suggest that, in both precancerous lesions and cancers, activated oncogenes induce stalling and collapse of DNA replication forks, which in turn leads to formation of DNA DSBs. This continuous formation of DNA DSBs may contribute to the genomic instability that characterizes the vast majority of human cancers. In addition, in precancerous lesions, these DNA DSBs activate p53, which, by inducing apoptosis or senescence, raises a barrier to tumor progression. Breach of this barrier by various mechanisms, most notably by p53 mutations, that impair the DNA damage response pathway allows cancers to develop. Thus, oncogene-induced DNA damage may explain two key features of cancer: genomic instability and the high frequency of p53 mutations. 相似文献
83.
A.T. Stiller J.P. Lulich E. Furrow 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2014,28(2):324-330
Background
Crystalline‐matrix urethral plugs have not been previously reported in dogs.Hypothesis/Objectives
To report the composition of urethral plugs in dogs, describe clinical features of the disease, and identify overrepresented breeds.Methods
Retrospective case series. A Minnesota Urolith Center (MUC) record search was performed for urethral plugs in dogs submitted during a 6‐year period. The composition of the plugs and signalment of affected dogs were recorded. Breed risk analysis was performed using a control group without plugs from the Veterinary Medical Center, University of Minnesota (VMC UMN). Breed risk was also calculated for a group of dogs with struvite (plugs and uroliths). Medical records for the subset of plug cases from the VMC UMN were reviewed and described.Results
Between 2006 and 2011, 42 urethral plugs from dogs were submitted to the MUC. All came from male dogs, and the mineral component of the majority (83%) was struvite. Thirty (71%) samples were from Pugs. Pugs were overrepresented in plug submissions (OR 179; CI 88–389; P < .001), and for struvite in general (OR 14.3; CI 7.9–24.4; P < .001). Nine of the dogs were treated at VMC UMN; all were castrated male Pugs. None of these cases had bacteriuria or positive urine cultures, and no underlying cause of plug formation was identified.Conclusions and Clinical Importance
When evaluating dogs with urethral obstruction, plugs need to be considered, especially in male Pugs. Further investigation into the underlying cause of plug formation in dogs is warranted. 相似文献84.
Biologically produced surfactants (SACs) can mobilize and solubilize non-aqueous phase liquids (NAPL) adsorbed onto soil constituents. The interest in microbial surfactants has increased during recent years due to their lower toxicity, higher biodegradability, selectivity and specific activity under extreme conditions than synthetic SACs. Main output of the project represents preparation of this yeast biosurfactant intended for washing of matrices contaminated by NAPL. The influence of cultivation media composition on biosurfactant production was studied and basic properties (critical micelle concentration (CMC), minimum surface tension) of isolated biosurfactants were compared with properties of synthetic surfactant with surface tension measurement. The interracial tension of the systems containing aqueous solutions of different concentrations and non-polar substances was measured with petroleum compounds (kerosene Jet A-l), aromatic and aliphatic hydrocarbons (represented by toluene and hexane). The solution of biosurfactant Yarrowia lipolytica (YAR) in the concentration range of 0-500 mg/L reduced interracial tension by 80% in all representative systems with model contaminants; biosurfactant Candida bombicola (CAN) was less efficient. Solubilization properties were proved with toluene and hexachlorocyclohexane (HCH) isomers alpha and gamma, and effective concentration of biosurfactants was determined as 100 mg/L for toluene and HCH. SACs produced by lipophilic yeast with non-toxic and non-pathogenic status (Yarrowia lipolytica, Candida sp., etc.) seem to be very promising. The results obtained will be used for the application of biosurfactants in the clean-up technologies as agents for the mobilization of non-polar contaminants as well as for stimulation of bioremediation processes. 相似文献
85.
Constitutive expression of Cry proteins in roots and border cells of transgenic cotton 总被引:3,自引:0,他引:3
Oliver G. G. Knox Vadakattu V. S. R. Gupta David B. Nehl Warwick N. Stiller 《Euphytica》2007,154(1-2):83-90
Transgenic cotton plants expressing Cry1Ac and Cry2Ab, from the soil bacterium Bacillus thuringiensis (Bt), provide effective control of certain lepidopteran pests, however, little is known about the proteins below ground expression.
We used ELISA to quantify in vitro expression of the Cry1Ac and Cry2Ab proteins in mucilage, root border cells and root tips in five transgenic cultivars of cotton compared to conventional
cultivar Sicot 189. Expression of Cry proteins in roots and border cells of the transgenic cotton cultivars was constitutive
and at detectable levels, with Cry1Ac and Cry2Ab protein expression ranging from <20 ppb to >100 pbb. To determine if genetically modified cotton demonstrated simple differences
in properties of the root, when compared to an elite parental line (cv. Sicot 189), we enumerated border cells on seedling
radicles. Border cell counts of 14 cultivars ranged from 0.2 to 1.1 × 104 cells per root tip with an average of 5 × 103 border cells. Border cell production in the transgenic cultivars was generally similar to that of both donor and elite parents,
the exception being the cultivar Sicot 189, which had substantially more border cells than all of its transgenic derivatives.
Comparison of border cell number with varietal disease resistance ranking found a limited relationship (r
2 = 0.65, n = 7) between border cell numbers and the commercial resistance rank against Fusarium wilt of cotton. The implications of
differences in cotton cultivar border cell number and root tip expression of Cry proteins for plant–microbe interactions in
the rhizosphere and the soil ecosystem are yet to be resolved. 相似文献
86.
Two IgG1 fragments were isolated from bovine colostral whey. Based on gel diffusion analysis, both fragments originated from the Fc portion of the molecule but were not identical to IgG1 Fc prepared by papain cleavage. The molecular weights were determined to be 66,000 and 14,000 daltons and it was hypothesized that the larger fragment could be a polymer of the smaller. No IgG1 Fab or IgG2 fragments could be demonstrated. 相似文献
87.
88.
Does closure of traditionally managed open woodlands threaten epigeic invertebrates? Effects of coppicing and high deer densities 总被引:1,自引:0,他引:1
The demise of traditional woodland management techniques, such as coppicing or woodland pasture, is causing a gradual closure of formerly sparse lowland woods across Central Europe. It is established that these processes threaten such organisms as butterflies and higher plants. Effects on other groups, such as epigeic invertebrates, are little known, hindering rational conservation decisions. We investigated the effects of stand openness on three epigeic groups, carabids (Carabidae), arachnids (Araneae + Opiliones) and myriapods-isopods (Chilopoda + Diplopoda + Oniscidea), in a lowland deciduous wood in the Czech Republic. Situating some of the traps in an intensive deer park allowed a simultaneous assessment of effects of high vs. low ungulate densities. Carabids reached the highest species richness in either sparse stands with low game or dense stands, high game. More arachnids occurred under low game and in sparse stands than under high game density and in dense stands. The highest richness of myriapods-isopods was in sparse stands with low game. Ordinations revealed that species of conservation concern (‘relic species’ according to C. European authors) tended to be associated with sparse stands and low game. A considerable proportion of epigeic woodland invertebrates, including many species of conservation concern, depends on preserving highly heterogeneous sparse canopy conditions. Restoring such conditions in selected areas will benefit these sensitive open woodland specialists while causing minimum harm to specialists of dense stands, that likely prosper in commercially managed high forests. 相似文献
89.
Bram Flahou Kim Van Deun Frank Pasmans Annemieke Smet Jiri Volf Ivan Rychlik Richard Ducatelle Freddy Haesebrouck 《Veterinary research》2012,43(1):75
Helicobacter (H.) suis colonizes the stomach of pigs and is the most prevalent gastric non-H. pylori Helicobacter species in humans. Limited information is available on host immune responses after infection with this agent and it is unknown if variation in virulence exists between different H. suis strains. Therefore, BALB/c and C57BL/6 mice were used to compare colonization ability and gene expression of various inflammatory cytokines, as determined by real-time PCR, after experimental infection with 9 different H. suis strains. All strains were able to persist in the stomach of mice, but the number of colonizing bacteria at 59 days post inoculation was higher in stomachs of C57BL/6 mice compared to BALB/c mice. All H. suis strains caused an upregulation of interleukin (IL)-17, which was more pronounced in BALB/c mice. This upregulation was inversely correlated with the number of colonizing bacteria. Most strains also caused an upregulation of regulatory IL-10, positively correlating with colonization in BALB/c mice. Only in C57BL/6 mice, upregulation of IL-1β was observed. Increased levels of IFN-γ mRNA were never detected, whereas most H. suis strains caused an upregulation of the Th2 signature cytokine IL-4, mainly in BALB/c mice. In conclusion, the genetic background of the murine strain has a clear impact on the colonization ability of different H. suis strains and the immune response they evoke. A predominant Th17 response was observed, accompanied by a mild Th2 response, which is different from the Th17/Th1 response evoked by H. pylori infection. 相似文献
90.
Crayfish in central and southern Ukraine with special focus on populations of indigenous crayfish Astacus pachypus (Rathke, 1837) and their conservation needs 下载免费PDF全文
Tomas Policar Volodymyr Bondarenko Oles Bezusyj Vlastimil Stejskal Jiri Kristan Oleksandr Malinovskyi Aiman Imentai Miroslav Blecha Yuriy Pylypenko 《水产资源保护:海洋与淡水生态系统》2018,28(1):6-16
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