1,196 research outputs found
A review of aflatoxin M1 in liquid milk
Mycotoxins continue to pose a health concern via human exposure to contaminated food. Aflatoxin M1 (AFM1), the hydroxylated metabolite of aflatoxin B1 (AFB1), may be found in the milk of dairy cattle and other mammals. In humans, AFM1 is excreted through the feces, urine, and in the case of lactating mothers, also in breast milk after consumption of aflatoxin contaminated food. Concentration of AFM1 in milk is a function of several factors, namely: animal type, milking day, milk yield, season, feeding regime, geographic, and climatic conditions. A linear relationship has been established between the amount of AFM1 in milk and the amount of AFB1 in feed consumed by animals, emphasized at first on the reduction or removal of AFB1 from feedstuffs and then elimination of AFM1 from milk. This review aims to bring up to date the current global status of AFM1 contamination of liquid milk destined for human consumption and the effects of processing and reduction methods on the elimination of aflatoxins from liquid milk
Natural occurrence of ochratoxin A contamination in commercial black and white pepper products.
The concentration of ochratoxin A (OTA) in 120 commercial pepper (84 pre-packed and 36 bulk samples), which consist of local and imported white and black pepper in powder and seed form in Malaysia were determined. The objective of the study was to investigate and compare OTA concentration in black pepper and white pepper being commercialized in Malaysia. Determination method was based on HPLC with fluorescence detection coupled with immunoaffinity column clean-up step. Mobile phase consisted of acetonitrile-water-acetic acid (49.5:49.5:1.0, v/v/v), and flow rate was 1 ml/min. The LOD was 0.02 ng/g, and the average recovery values of OTA ranged from 79.5 to 92.0% in black pepper and 81.2-90.3% in white pepper. A total of 57 samples (47.5%) were contaminated with OTA ranging from 0.15 to 13.58 ng/g. The results showed that there was a significant difference between type of pepper and brands. OTA concentration in black pepper was significantly higher than white pepper (p < 0.05). The highest concentration of ochratoxin, 13.58 ng/g, was detected in a sample of black pepper seed followed by 12.64 ng/g in a sample of black pepper powder, both were bulk samples purchased from open market
Optimizing dynamical network structure for pinning control
Controlling dynamics of a network from any initial state to a final desired state has many applications in different disciplines from engineering to biology and social sciences. In this work, we optimize the network structure for pinning control. The problem is formulated as four optimization tasks: i) optimizing the locations of driver nodes, ii) optimizing the feedback gains, iii) optimizing simultaneously the locations of driver nodes and feedback gains, and iv) optimizing the connection weights. A newly developed population-based optimization technique (cat swarm optimization) is used as the optimization method. In order to verify the methods, we use both real-world networks, and model scale-free and small-world networks. Extensive simulation results show that the optimal placement of driver nodes significantly outperforms heuristic methods including placing drivers based on various centrality measures (degree, betweenness, closeness and clustering coefficient). The pinning controllability is further improved by optimizing the feedback gains. We also show that one can significantly improve the controllability by optimizing the connection weights
In vitro response of promising tomato genotypes for tolerance to osmotic stress
Drought is a major abiotic factor that limits plant growth and productivity. Tomato is an important vegetable crop and area under production is limited by irrigation water scarcity. Four cultivars of tomato were grown as callus cultures under conditions of water stress, which was induced by addition of polyethylene glycol (6000) in the medium. The presence of PEG in the medium decreased relative growth rate and increased dry matter content in all treatments compared with the control. In all cultivars, proline levels increased in response to water stress. Also, there was decreased shoot induction in all cultivars with increase PEG treatments. The number of shoot forming in PS-10 and Peto was higher then Roma and Nora cultivars. This result can be used for in vitro screening and manipulations of tomato cultivars for improvement of drought tolerance
Effect of gamma radiation on reduction of mycotoxins in black pepper.
Gamma ray was applied to reduce mycotoxins, i.e. ochratoxin A (OTA) and aflatoxins B1, B2, G1 and G2 (AFB1, AFB2, AFG1 and AFG2) in black pepper. Response surface methodology (RSM) was applied to evaluate the effect of dose of gamma ray ranging from 0 to 60 kGy and mycotoxin concentration ranging from 10 to 100 ng g−1 on the mycotoxin reduction. The maximum reduction was found at 60 kGy which was 52%, 43%, 24%, 40% and 36% for OTA, AFB1, AFB2, AFG1 and AFG2, respectively. Results showed the gamma rays even at 60 kGy were not effective in completely destroying of ochratoxin and aflatoxins
Wet-spinning of PEDOT:PSS/functionalized-SWNTs composite: A facile route toward production of strong and highly conducting multifunctional fibers
With the aim of fabricating multifunctional fibers with enhanced mechanical properties, electrical conductivity and electrochemical performance, we develop wet-spinning of composite formulation based on functionalized PEG-SWNT and PEDOT:PSS. The method of addition and loading are directly correlated to the quality and the ease of spinnability of the formulation and to the mechanical and electrical properties of the resultant fibers. Both the fiber modulus (Y) and strength (σ) scaled linearly with PEG-SWNT volume fraction (Vf). A remarkable reinforcement rate of dY/dVf = 417 GPa and dσ/dVf = 4 GPa were obtained when PEG-SWNTs at Vf ≤ 0.02. Further increase of PEG-SWNTs loading (i.e. up to Vf 0.12) resulted in further enhancements up to 22.8 GPa and 254 MPa in Modulus and ultimate stress, respectively. We also show the enhancement of electrochemical supercapacitor performance of composite fibers. These outstanding mechanical, electrical and electrochemical performances place these fibers among the best performing multifunctional composite fibers
TOWARDS CHANGE VALIDATION IN DYNAMIC SYSTEM UPDATING FRAMEWORKS
Dynamic Software Updating (DSU) provides mechanisms to update a program without stopping its execution. An indiscriminate update that does not consider the current state of the computation, potentially undermines the stability of the running application. Determining automatically a safe moment, the time that the updating process could be started, is still an open crux that usually neglected from the existing DSU systems. The program developer is the best one who knows the program semantics and the logical relations between two successive versions as well as the constraints which should be respected in order to proceed with the update. Therefore, a set of meta-data has been introduced that could be exploited to explain the constraints of the update. These constraints should be considered at the dynamic update time. Thus, a runtime validator has been designed and implemented to verify these constraints before starting the update process. The validator is independent of existing DSU systems and can be plugged into DSUs as a pre-update component. An architecture for validation has been proposed that includes the DSU, the running program, the validator, and their communications.
Along with the ability to describe the restrictions by using meta-data, a method has been presented to extract some constraints automatically. The gradual transition from the old version to the new version requires that the running application frequently switches between executing old and new code for a transient period. Although this swinging execution phenomenon is inevitable, its beginning can be selected. Considering this issue, an automatic method has been proposed to determine which part of the code is unsafe to participate in the swinging execution. The method has been implemented as a static analyzer which can annotate the unsafe part of the code as constraints. This approach is demonstrated in the evolution of the various versions of three different long-running software systems and compared to other approaches.
Although the approach has been evaluated by evolving various programs, the impact of different changes in the dynamic update is not entirely clear. In addition, the study of the effect of these changes can identify code smells on the program, regarding the dynamic update issue. For the first time, the code smells have been introduced that may cause a run-time or syntax error on the dynamic update process. A set of candidate error-prone patterns has been developed based on programming language features and possible changes for each item. This set of 75 patterns is inspected by three distinct DSUs to identify problematic cases as code smells. Additionally, error- prone patterns set can be exploited as a reference set by other DSUs to measure own flexibility
Study of Cultivation and Domestication \u3ci\u3eAllium hirtifolium\u3c/i\u3e in Hamadan Provinces Rangeland, Iran
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