Six methods were compared for detection of three strains of Escherichia coli O157:H7 in enrichments of inoculated apple juice. Juice was inoculated at levels varying from 0.1 to 100 CFU/ml and centrifuged after overnight storage at 4 degrees C, and pellets were incubated at 37 degrees C in nonselective enrichment broth. At hourly intervals between 5 and 10 h and at 24 h, the enrichments were tested for E. coli O157:H7 by direct fluorescent antibody (DFA), antibody-direct epifluorescent filter technique (Ab-DEFT), direct selective plating on sorbitol MacConkey agar (SMA), immunomagnetic separation coupled to either selective plating (IMS-SMA) or the polymerase chain reaction (IMS-PCR), and flow cytometry (FC). The most consistent detection of 0.1 CFU/ml of the slowest growing strain of the pathogen was provided by the IMS-SMA and IMS-PCR after 8 h of enrichment. The time required for detection at the level of 0.1 CFU/ml for each assay was Ab-DEFT, 11 h; IMS-PCR, 16 h; FC, 24 h; IMS-SMA, 32 h; and SMA, 48 h. Absolute detection limits (without enrichment) were: IMS-PCR, 10(3) CFU/ml; Ab-DEFT and IMS-SMA, 10(4) CFU/ml; SMA, 10(5) CFU/ml; and DFA, 10(6) CFU/ml. Recovery of the pathogen (10 CFU/ml) in apple juice after 28 days of 4 degrees C storage was possible by means of an 8-h enrichment and Ab-DEFT, IMS-PCR, or IMS-SMA. 相似文献
The growth of the Internet of Things (IoTs) and the number of connected devices is driven by emerging applications and business models. One common aim is to provide systems able to synchronize these devices, handle the big amount of daily generated data and meet business demands. This paper proposes a cost-effective cloud-based architecture using an event-driven backbone to process many applications’ data in real-time, called REDA. It supports the Amazon Web Service (AWS) IoT core, and it opens the door as a free software-based implementation. Measured data from several wireless sensor nodes are transmitted to the cloud running application through the lightweight publisher/subscriber messaging transport protocol, MQTT. The real-time stream processing platform, Apache Kafka, is used as a message broker to receive data from the producer and forward it to the correspondent consumer. Micro-services design patterns, as an event consumer, are implemented with Java spring and managed with Apache Maven to avoid the monolithic applications’ problem. The Apache Kafka cluster co-located with Zookeeper is deployed over three availability zones and optimized for high throughput and low latency. To guarantee no message loss and to simulate the system performances, different load tests are carried out. The proposed architecture is reliable in stress cases and can handle records goes to 8000 messages in a second with low latency in a cheap hosted and configured architecture.
Titanium alloy is well known for its difficulty to machine, owing to the important “tool wear” phenomenon. Machining assistance is an interesting solution to lengthen the tool lifetime. In this study, we focused on the effect of cryogenic assistance—during machining of Ti17—on the tool wear and cutting forces for different combinations of cutting speed, feed rate and depth of cut. Compared to conventional lubrication, cryogenic support lengthens the tool life for all tested conditions and has no significant influence on cutting force. A comparison of the cryogenic effect and high-pressure water jet assistance is also presented. 相似文献
The effect of highly purified sardine proteins was compared with that of casein on serum and lipoproteins lipid peroxidation and reverse cholesterol transport. Lecithin:cholesterol acyltransferase (LCAT) activity, high density lipoproteins (HDL2 and HDL3) composition and serum lipid and lipoproteins peroxidation were determined in rats fed a cholesterol-rich diet. Hypercholesterolemic rats were divided into two groups fed diets enriched with cholesterol and containing 20% of highly purified sardine proteins (SPc) or casein (CASc) for 28 days. A control group was fed a standard diet (CAS). Compared with CAS and CASc, the thiobarbituric acid reactive substances (TBARS) concentrations of low density lipoprotein (LDL)–HDL1 in SPc were 3.5- and 1.7-fold higher compared with casein diets. TBARS in HDL2 and HDL3 were, respectively, 2.3- and 1.6-fold lower in SPc compared with CASc. In SPc group, LCAT activity was higher compared to CASc and CAS (P < 0.05). Purified sardine proteins had no beneficial effects on LDL-cholesterol and lipid peroxidation. However, they reduced HDL oxidation and improved reverse cholesterol transport, in the hypercholesterolemic rat. 相似文献
Color matching and recipe prediction is one of the most important aspects of color science. In this article, a new method using ant colony algorithm is developed to optimize the color formulation step. Four direct dyes, namely CI Direct Red 227, CI Direct Orange 34, CI Direct Blue 85, and CI Direct Black 22 were used and mixed to dye cotton fabrics. The aim is to reproduce the desired shades by determining the dyes and their respective concentrations to add in the dye bath. The criterion of optimization is to minimize the CMC color differences between the target color and the color obtained by the proposed recipes. The developed algorithm showed good performances with small color differences all lower than the unit. 相似文献
AbstractThis article models and optimizes the effect of dyeing parameters on obtained color of fabric samples dyed with three cold bifunctional reactive dyes, namely, C.I. Reactive Yellow 145, C.I. Reactive Red 238 and C.I. Reactive Blue 235, in order to use them in color formulation. The studied dyeing parameters are electrolyte concentration, alkali concentration, liquor-to-fiber ratio and temperature of dyeing process. The influence of these parameters was analyzed for four different shades: 0.1%, 1%, 2% and 4%. Two criteria of evaluation are studied and optimized: the exhaustion and the fixation yields. Linear modeling of optimal concentrations of electrolyte and alkali according to the dye concentration was developed, allowing the calculation of optimal quantities which should be added to the dye bath for any dye concentration. Color coordinates and fastness (washing, rubbing and light fastness) of samples dyed with optimal conditions are also evaluated and discussed. 相似文献
The possibility to reuse residual dye baths for wool dyeing with acid and reactive dyestuffs (Blue Marine Irganol 2RLS and Blue Lanasyn BLS, respectively) was investigated in this study. The residual dye baths were reconstituted and reused 20 consecutive times for dye concentration of 1%. A series of colorimetric measurements were carried out for the obtained samples in order to evaluate the conformity and the uniformity of their color as well as their dyeing fastness. In particular, we were interested in wash, rubbing, and light fastness. The obtained results for these three criteria of evaluation were very satisfactory: (1) color conformity (expressed in Colour Measurement Committee (2:1) and CIEDE2000 color differences) lower than the textile threshold of 1, (2) good evenness, and (3) color fastness not deteriorated in spite of the multiple reuses of dye baths. In this paper, the feasibility and efficiency of this technique was proved to considerably reduce water, dyes, and auxiliary quantities without disturbing the quality of the dyeing behavior. 相似文献
Summary Novel furanic polyureas were synthesised by solution polycondensation reactions between difuranic diamines and aliphatic diisocyanates
and then converted to the corresponding poly(parabanic acid)s by heterocyclisation with oxalyl chloride. These condensation
reactions and chemical modifications were first studied with model compounds. The polymers were characterised by FTIR and
1H-NMR spectroscopy and inherent viscosity. 相似文献