Infrastructure as a Service (IaaS) is a cloud computing service provided over the internet to facilitate the provisioning of various services such as storage, processes, etc. The provider in the IaaS market may offer some purchasing plans including: reservation, on-demand, and spot plans for its resources. As in real scenarios, demand volume for each plan is assumed to be a random variable with a given probability distribution. The provider maximizes its average revenue in the long run by optimal allocation of its resources among the plans. We formulate an Integer Linear Programming (ILP) model with a stochastic constraint, to determine the number of resources to be allocated for each plan in every time slot in the planning horizon. First, fixed prices are considered for each plan, then two mechanisms of Continuous Double Auction and Second Price Sealed Bid Auction are considered for reservations and spot plans, respectively, to obtain market-driven prices of the services. The Seasonal Weighted Moving Average method is used to predict the amount of demand in every slot. Finally, the proposed mechanisms are evaluated through simulations and the results confirm the effectiveness of the methods in maximizing the revenue and overall utilization of the available IaaS capacity.
The new pre-concentration technique, hollow fiber-solid phase microextraction based on carbon nanotube reinforced sol-gel and liquid chromatography-photodiode array detection was applied to determination of aflatoxins B(1), B(2) (AFB(1), AFB(2)) in rice, peanut and wheat samples. This research provides an overview of trends related to synthesis of solid phase microextraction (SPME) sorbnents that improves the assay of aflatoxins as the semi-polar compounds in several real samples. It mainly includes summary and a list of the results for a simple carbon nanotube reinforced sol-gel in-fiber device. This device was used for extraction, pre-concentration and determination of aflatoxins B1, B2 in real samples. In this technique carbon nanotube reinforced sol was prepared by the sol-gel method via the reaction of phenyl trimethoxysilane (PTMS) with a basic catalyst (tris hydroxymethyl aminomethan). The influences of microextraction parameters such as pH, ageing time, carbon nanotube contents, desorption conditions, desorption solvent and agitation speed were investigated. Optimal HPLC conditions were: C(18) reversed phase column for separation, water-acetonitril-methanol (35:10:55) as the mobile phase and maximum wavelength for detection was 370 nm. The method was evaluated statistically and under optimized conditions, the detection limits for the analytes were 0.074 and 0.061 ng/mL for B1 and B2 respectively. Limit of quantification for B1 and B2 was 0.1 ng/mL too (n=7). The precisions were in the range of 2.829-2.976% (n=3), and linear ranges were within 0.1 and 400 ng/mL. The method was successfully applied to the analysis of cereals (peanut, wheat, rice) with the relative recoveries from 47.43% to 106.83%. 相似文献
A 2 × 3 factorial experiment was conducted to evaluate the effect of partial substitution of dietary fish meal with soybean meal and citric acid (CA) supplementation on growth, food utilization, muscle composition and nutrient digestibility of Beluga, Huso huso. Three isonitrogenic and isoenergetic diets, as SBM1 (soybean meal protein (SBP):fishmeal protein (FP) = 1:3), SBM2 (SBP:FP = 2:3) and SBM3 (SBP:FP = 1:1) containing two levels of CA (0 and 30 g kg−1) were fed to triplicate groups of fish for 8 weeks. The results revealed that adding CA increased (P<0.05) the weight gain (WG), specific growth rate (SGR) and protein efficiency ratio (PER) and decreased (P<0.05) food conversion rate (FCR) whereas partial substitution of fishmeal with soybean meal decreased (P<0.05) growth performance. Partial replacement of fishmeal with SBM (P=0.021) as well as CA supplementation (P=0.019) and their interaction (P<0.001) affected hepatosomatic index (HSI). No differences (P>0.05) were observed for viscerosomatic index (VSI) among treatments (P>0.05). No differences (P>0.05) were detected in moisture, protein of muscle sample among treatments, but lipid content was reduced (P<0.05) while ash content increased (P=0.035) by CA. Soybean meal decreased (P<0.05) nutrient digestibility, whereas CA improved apparent protein and phosphorus (P) digestibility (P=0.011 and P<0.001 respectively). No interaction (P<0.05) between levels of SBM and CA was found on these parameters. Results of the present study indicate that Beluga has a limited ability to utilize SBM as a protein source in practical diets whereas CA can improve growth and nutrient utilization in Beluga. 相似文献
The effect of Bombyx mori nuclear polyhedrosis virus (BmNPV) on biochemical changes of TC-100 medium containing 10% fetal bovine serum (FBS) in embryonic
primary cultures of silkworm was investigated. The primary cultures that reached 60% confluence were infected by 0.5, 1, and
2-ml viral inoculums (diluted with TC-100 medium representing multiplicity of infection (MOI) of 0.25, 0.5, and 1). Glucose,
uric acid, urea, total protein, cholesterol, and alkaline phosphatase were measured in the medium of BmNPV-infected primary
cultures. All biochemical compounds showed significant changes. Glucose decreased considerably by about 55 mg/ml, while different
concentrations of the virus inoculums did not demonstrate significant differences among them. Total protein had only increased
in 2 ml concentration and there were no changes in other concentrations. Uric acid as a by-product accumulated dramatically
in all concentrations, while the amount of urea reduced in all treatments and this reduction was more evident in lower concentrations.
Cholesterol consumption was high in cultures postinfection, while alkaline phosphatase (ALP) activity decreased in infected
cells. 相似文献
Biotechnology Letters - Tumor suppressor miRNAs, miR-15a and miR-16–1, with high-specificity and oncogenic targeting of Bcl-2, can target tumor tissues. Disadvantages of the clinical... 相似文献
Nonenzymatic glycation of biomacromolecules occurs due to the diabetes mellitus and ageing. A number of small molecules, known
as chemical chaperones, stabilize protein conformation against thermal and chemically induced denaturation. These compounds
are including: polyamines (e.g. spermine and spermidine), amino acids (e.g. lysine) and polyols (e.g. glycerol). In this study
the effect of spermidine (Spd), spermine (Spm), and glycerol on glycation, structure and function of lysozyme (LZ), as an
extra-cellular protein, by different techniques is investigated. LZ is incubated with or without glucose (50 or 100 mM) in
the absence or presence of Spd/Spm/glycerol at 37 °C up to 16 weeks. All the observed changes of glycated-LZ in comparison
with the native protein, including: increased fluorescence emission, alteration in the secondary and tertiary structure, and
reduced electrophoretic mobility- indicate its structural changes that are accompanied with its reduced activity. Glucose
in the presence or absence of Spd induces the protein dimerization, but glucose plus Spm induces its trimmerization. In contrast,
glycerol inhibits the LZ glycation and prevents the large changes on its structure and function. Glucose binds lysine residues,
decreases the protein positive charges and induces some alterations in its structure and activity. Polyamines also directly
bind to LZ, increase its positive charges and hence induce more glycation; more conformational changes, oligomerization and
its inactivation in the presence of glucose, but glycerol affect the protein environment and preserve protein from these harmful
effects. 相似文献
Ailanthusaltissima or Ailanthusglandulosa (Simaroubaceae) is known as tree of heaven. It is a dioecious plant with staminate and pistillate flowers that grow on separate trees. In recent years, A.altissima has been frequently planted in numerous areas, especially in arid and semiarid lands of Iran and also used as an ornamental tree in several Iran cities including Kerman. The aim of this research was to identify IgE-binding proteins responsible for type I hypersensitivities of A. altissima pollen extract. In this study, pollen’s proteins were extracted and analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Total protein content of pollen extracts was measured by Bradford assay. Allergenicity of pollen extract was evaluated by skin test and immunoblotting. Results showed that total protein concentration of A.altissima pollen was found to be 1.34 μg μl?1. In A. altissima pollen extract, different protein fractions were identified by SDS-PAGE mostly at 42, 53.7, 63, 87.7, 100 and 120 kDa. Skin tests showed a delayed hypersensitivity. Immunoblotting of A. altissima pollen extract with pooled subject’s sera detected a major IgE-binding component of 42 kDa. Moreover, these results will provide a platform for cloning cDNA encoding allergenic protein from A.altissima pollen. 相似文献