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排序方式: 共有240条查询结果,搜索用时 414 毫秒
31.
Maria Carmen Collado Jussi Meriluoto Seppo Salminen 《European Food Research and Technology》2008,226(5):1065-1073
Autoaggregation has been correlated with adhesion, which is known to be a prerequisite for colonization and infection of the
gastrointestinal tract by many pathogens. The coaggregation properties of probiotic strains with pathogens as well as their
ability to displace pathogens are of importance for therapeutic manipulation of the aberrant intestinal microbiota. Consequently,
the ability to aggregate and coaggregate are desirable properties for probiotics in health-promoting foods. Aggregation assays
and bacterial adhesion to hydrocarbons (BATH test) demonstrated significant differences in cell surface properties among the
tested commercial probiotic strains. Hydrophobicity increased when the cells were heat-inactivated. All probiotic strains
tested showed aggregation abilities with the pathogen strains tested, but the results were strain-specific and dependent on
time and incubation conditions. Our results indicate that the ability to autoaggregate, together with cell-surface hydrophobicity
and coaggregation abilities with pathogen strains can be used for preliminary screening in order to identify potentially probiotic
bacteria suitable for human or animal use. 相似文献
32.
Hagren V von Lode P Syrjälä A Korpimäki T Tuomola M Kauko O Nurmi J 《International journal of food microbiology》2008,125(2):158-161
We describe a system consisting of rapid sample enrichment and homogeneous end-point PCR analysis that enables the detection of Salmonella in various food matrices in 8 h. Sample preparation starts with 6 h enrichment step in supplemented broth, after which Salmonella cells are collected with immunomagnetic particles. The particles are washed and dispensed to ready-to-use PCR reaction vessels, which contain dried assay-specific reagents and an internal amplification control. PCR is performed with a novel instrument platform utilising the sensitive label technology of time-resolved fluorometry. Qualitative assay results are automatically interpreted and available in 45 min after sample addition. The overall accuracy, sensitivity and specificity of the Magda CA Salmonella system were 99.1%, 98.4% and 100.0%, respectively, based on the evaluation of 107 samples (beef, pork, poultry and ready-to-eat meals) artificially contaminated with sub-lethally injured Salmonella cells. 相似文献
33.
According to decision by the rector of University of Tampere, a version of the paper was submitted and published due to negligence. 相似文献
34.
Yuanjing Lin Mallika Bariya Hnin Yin Yin Nyein Liisa Kivimki Sanna Uusitalo Elina Jansson Wenbo Ji Zhen Yuan Tuomas Happonen Christina Liedert Jussi Hiltunen Zhiyong Fan Ali Javey 《Advanced functional materials》2019,29(33)
Development of reliable glucose sensors for noninvasive monitoring without interruption or limiting users' mobility is highly desirable, especially for diabetes diagnostics, which requires routine/long‐term monitoring. However, their applications are largely limited by the relatively poor stability. Herein, a porous membrane is synthesized for effective enzyme immobilization and it is robustly anchored to the modified nanotextured electrode solid contacts, so as to realize glucose sensors with significantly enhanced sensing stability and mechanical robustness. To the best of our knowledge, this is the first report of utilizing such nanoporous membranes for electrochemical sensor applications, which eliminates enzyme escape and provides a sufficient surface area for molecular/ion diffusion and interactions, thus ensuring the sustainable catalytic activities of the sensors and generating reliable measureable signals during noninvasive monitoring. The as‐assembled nanostructured glucose sensors demonstrate reliable long‐term stable monitoring with a minimal response drift for up to 20 h, which delivers a remarkable enhancement. Moreover, they can be integrated into a microfluidic sensing patch for noninvasive sweat glucose monitoring. The as‐synthesized nanostructured glucose sensors with remarkable stability can inspire developments of various enzymatic biosensors for reliable noninvasive composition analysis and their ultimate applications in predictive clinical diagnostics, personalized health‐care monitoring, and chronic diseases management. 相似文献
35.
Knutas Antti van Roy Rob Hynninen Timo Granato Marco Kasurinen Jussi Ikonen Jouni 《Multimedia Tools and Applications》2019,78(10):13593-13612
Multimedia Tools and Applications - Personalization is an upcoming trend in gamification research, with several researchers proposing that gamified systems should take personal characteristics into... 相似文献
36.
Riaz Uddin Mondal Tapani Ristaniemi Jussi Turkka 《International Journal of Wireless Information Networks》2017,24(4):413-423
Wireless Local Area Network (WLAN) positioning has become a popular localization system due to its low-cost installation and widespread availability of WLAN access points. Traditional grid-based radio frequency (RF) fingerprinting (GRFF) suffers from two drawbacks. First it requires costly and non-efficient data collection and updating procedure; secondly the method goes through time-consuming data pre-processing before it outputs user position. This paper proposes Cluster-based RF Fingerprinting (CRFF) to overcome these limitations by using modified Minimization of Drive Tests data which can be autonomously collected by cellular operators from their subscribers. The effect of environmental changes and device variation on positioning accuracy has been carried out. Experimental results show that even under these variations CRFF can improve positioning accuracy by 15.46 and 22.30% in 95 percentile of positioning error as compared to that of GRFF and K-nearest neighbour methods respectively. 相似文献
37.
Oxidation of MC-LR and -RR with chlorine and potassium permanganate: toxicity of the reaction products 总被引:3,自引:0,他引:3
Toxin-producing cyanobacteria are abundant in surface waters used as drinking water resources. Microcystins (MC) produced by certain cyanobacteria present acute and chronic toxicity, and their removal in drinking water treatment processes is of increasing concern. Previous studies have demonstrated that chlorine and potassium permanganate are feasible oxidants for the removal of MCs present in drinking water resources, although the oxidation might lead to toxic oxidation products. In this paper, the toxicity of the oxidation products of MC-LR and -RR has been studied using protein phosphatase 1 inhibition assay (PPIA). The HPLC and ELISA analyses correlated with the PPIA results for both toxins. The samples containing the oxidation products were fractionated by HPLC and the toxicity of the fractions was tested with PPIA. The results revealed that protein phosphatase 1 inhibition emerged only from intact MC, while the oxidation products were non-toxic. Similar results were obtained in experiments performed in natural waters: no reaction products or interactions exhibiting protein phosphatase 1 inhibition were detected. 相似文献
38.
Heikkinen V Lenz R Jetsu T Parkkinen J Hauta-Kasari M Jääskeläinen T 《Journal of the Optical Society of America. A, Optics, image science, and vision》2008,25(10):2444-2458
The problem of estimating spectral reflectances from the responses of a digital camera has received considerable attention recently. This problem can be cast as a regularized regression problem or as a statistical inversion problem. We discuss some previously suggested estimation methods based on critically undersampled RGB measurements and describe some relations between them. We concentrate mainly on those models that are using a priori information in the form of high-resolution measurements. We use the "kernel machine" framework in our evaluations and concentrate on the use of multiple illuminations and on the investigation of the performance of global and locally adapted estimation methods. We also introduce a nonlinear transformation of reflectance values to ensure that the estimated reflection spectra fulfill physically motivated boundary conditions. The reported experimental results are derived from measured and simulated camera responses from the Munsell Matte, NCS, and Pantone data sets. 相似文献
39.
Friction between ice-Ih and hexagonal boron nitride (h-BN) has been determined by periodic ab initio calculations. Surfaces
of ice-Ih and h-BN were brought into sliding contact, and the interaction energies were calculated as a function of interplanar
distance and lateral displacement of the surfaces. The friction between the surfaces was calculated from the interaction energies,
producing a friction coefficient of 0.140. Friction is further influenced at high loads by a tribochemical reaction between
ice-Ih and h-BN. 相似文献
40.
We consider the problem of dynamically hedging a fixed portfolio of assets in the presence of non-linear instruments and transaction costs, as well as constraints on feasible hedging positions. We assume an investor maximizing the expected utility of his terminal wealth over a finite holding period, and analyse the dynamic portfolio optimization problem when the trading interval is fixed. An approximate solution is obtained from a two-stage numerical procedure. The problem is first transformed into a nonlinear programming problem which utilizes simulated coefficient matrices. The nonlinear programming problem is then solved numerically using standard constrained optimization techniques. 相似文献