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1.
Marzieh Moosavi-Nasab Ali R. Taherian Maryam Bakhtiyari Asgar Farahnaky Hamed Askari 《Food and Bioprocess Technology》2012,5(2):638-647
This study examines and compares the structural and rheological properties of succinoglycan exopolysaccharide made by fermentation
of sucrose or date syrup at identical temperature, pH, and total soluble solid. Using thin-layer chromatography (TLC), Fourier
transform infrared (FTIR) spectroscopy, and rotational viscometery structural and rheological properties of prepared exopolysaccharides
were assessed. The variables under studies were biogum concentrations (0.5%, 1.0%, 1.5%, and 2.0% w/w), temperature (5, 25 and 40°C), and pH (2.5, 4.0, 7.0, and 10.0). Results revealed that the quantity of exopolysaccharide
produced in the date syrup (DSE) medium was three to five times greater than that of sucrose (SE) medium. The biogums exhibited
non-Newtonian, shear-thinning behavior, and the viscosity of DSE was higher than SE at all tested concentrations. The TLC
and FTIR spectroscopy assessments designated that the biogum is composed of glucose and galactose units, carrying a carboxylic
group and indicated the presence of succinoglycan. The outcomes of this study could be useful to food industries seeking low
cost biogum. 相似文献
2.
Rosiglitazone,but Not Epigallocatechin‐3‐Gallate,Attenuates the Decrease in PGC‐1α Protein Levels in Palmitate‐Induced Insulin‐Resistant C2C12 Cells
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Alteration of lipid metabolism is an important mechanism for the treatment of insulin resistance. PGC‐1α, a key regulator of mitochondrial biogenesis and function, plays an important role in the improvement of insulin sensitivity by increasing fatty acids β‐oxidation. In the present study, the effects of epigallocatechin‐3‐gallate (EGCG), an anti‐obesity agent and enhancer of lipid catabolism, on PGC‐1α protein expression was examined and compared with anti‐diabetic drug rosiglitazone (RGZ). After differentiation of C2C12 myoblasts to myotubes, insulin resistance was induced by palmitate treatment. Then the expression of the PGC‐1a gene and glucose uptake were evaluated before and after treatment with RGZ and EGCG. Palmitate treatment significantly decreased PGC‐1α protein expression in C2C12 cells (P < 0.05). RGZ could restore the expression of PGC‐1α in palmitate treated cells (P > 0.05), while EGCG had no significant effect on the expression of this gene (P < 0.05). RGZ and EGCG significantly improved glucose uptake (by 2‐ and 1.54‐fold, respectively) in myotubes treated with palmitate. These data suggest that RGZ and EGCG both exert their anti‐diabetic activity by increasing insulin sensitivity, but with different molecular mechanisms. This effect of RGZ, unlike EGCG, is mediated, at least partly, by increasing PGC‐1α protein expression. 相似文献
3.
An Adaptive Hybrid ARQ Scheme 总被引:1,自引:0,他引:1
A hybrid ARQ in which the transmitter adaptively selects an FEC code according to the channel condition is presented and analyzed. The code is selected according to the past transmissions and acknowledgements by an algorithm which is a generalization of that in [1]. The throughput is obtained as a function of the frame error rate for a general system employing the adaptive hybrid ARQ with acknowledgements that arrive instantly on an error-free return channel. The throughput is obtained as a function of the signal-to-noise ratio for an example quad rate system employing convolutional codes with non-coherent frequency shift keying over the uncorrelated Rayleigh fading channel. This allows the best choice for the parameters of the algorithm to be made. In the case that the channel bit errors are independent, the generalization offers performance improvement of less than 10% over that in [1]. But when the channel errors are bursty, as in the case of Rayleigh fading with finite bit interleaving, the generalization offers throughput improvement as high as 24%. We go on to consider incorporating code combining with the adaptive scheme to form an adaptive memory hybrid ARQ. Simulation of a system using complementary punctured convolutional codes with 4 code rates shows that 2-level code combining can extend the adaptive scheme's useful throughput into the low SNR region by approximately 4 dB. 相似文献
4.
The use of polymeric building materials has been grown in many countries of Middle East in recent years. However, there are only a few fire testing laboratories in this region. Therefore, development of a method for controlling the reaction to fire of materials with bench scale tests is necessary. Providing a framework for classification of thermal fire hazard of materials based on bench scale heat release rate results was attempted. The fire behavior of 10 polymeric building materials was tested with cone calorimeter. The relationship between reaction to fire variables and physical properties of tested samples was examined. The thermal fire hazards of materials were assessed using methods presented by different researchers and with Conetools software. The results revealed that time to ignition, peak rate of heat release, and total heat release are essential variables for determining the fire hazard of materials. A classification method is proposed, which can be used in building codes in countries where the full‐scale test facilities are not available. The method also can be used for quality control purpose and evaluation of fire behavior of materials in bench scale by manufacturers. An example of potential requirements for interior finishes for some occupancy types is also presented. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
5.
Ahmed Patel Mona Taghavi Kaveh Bakhtiyari Joaquim Celestino Júnior 《Journal of Network and Computer Applications》2013,36(1):25-41
The distributed and open structure of cloud computing and services becomes an attractive target for potential cyber-attacks by intruders. The traditional Intrusion Detection and Prevention Systems (IDPS) are largely inefficient to be deployed in cloud computing environments due to their openness and specific essence. This paper surveys, explores and informs researchers about the latest developed IDPSs and alarm management techniques by providing a comprehensive taxonomy and investigating possible solutions to detect and prevent intrusions in cloud computing systems. Considering the desired characteristics of IDPS and cloud computing systems, a list of germane requirements is identified and four concepts of autonomic computing self-management, ontology, risk management, and fuzzy theory are leveraged to satisfy these requirements. 相似文献
6.
Throughput performance of memory ARQ schemes 总被引:2,自引:0,他引:2
We present a throughput analysis for the memory automatic repeat request (ARQ) schemes with self-decodable frame retransmissions, taking into account frame header and frame acknowledgment failure probability. A lower bound on the throughput is obtained for a very general class of schemes which encompasses many of those proposed in the literature. Numerical results are given for several example systems, and suitable header and acknowledgment forward error correction (FEC) encodings are determined 相似文献
7.
Majid Azarang Arezo Bakhtiyari Reza Rakhshani Abdol Mahmood Davarpanah Mousa Aliahmad Maryam Farifteh Jahantigh 《Advanced Powder Technology》2021,32(2):504-514
GO and Co(NO3)2 were respectively used as rGO and Co3O4 precursors for preparing magnetically separable Co3O4NPs attached Co3O4NPs@rGO nanocomposites by a straightforward sol–gel technique. To characterize the nanocomposite materials, FESEM, EDX, elemental mapping, XRD, FTIR, Raman spectroscopy, UV–vis, VSM and BET were employed. When exposed to UV rays, the nanocomposite showed extraordinary photocatalytic degradation of MO dye. According to the measurements of photocatalytic activity, the highly efficient photocatalytic efficiency of the nanocomposite could be attributed to preventing electron-hole recombination by highly effective electron transfer between rGO and semiconductor NPs. The nanocomposite succeeded in the efficient degradation of MO dye, even after five photocatalytic cycles. 相似文献
8.
9.
Salar Bakhtiyari Reza Meshkani Mohammad Taghikhani Bagher Larijani Khosrow Adeli 《Lipids》2010,45(3):237-244
Insulin resistance is the central defect in type 2 diabetes and obesity. During the development of insulin resistance a lipid
accumulation is accompanied by increased PTP-1B expression in the muscle. The aim of this study was to examine the effects
of PTP-1B knockdown on insulin signaling and insulin resistance in the presence or absence of palmitate in C2C12 skeletal
muscle cells. A stable C2C12 cell line was established using short hairpin RNA (shRNA) to knockdown protein expression of
PTP1B. Analysis of PTP-1B protein expression and phosphorylation and protein levels of IRS-1 and Akt were detected by western
blot. The effects of PTP-1B knockdown on the glucose uptake was also measured in C2C12 cells. The stable C2C12 cell line harboring
the PTP-1B shRNA showed 62% decrease in the PTP-1B protein levels. 0.5 mM palmitate significantly induced insulin resistance
in both control (26%) and PTP-1B knockdown cells (16.5%) compared to the untreated cells. Under treatment with palmitate,
insulin stimulated phosphorylation of IRS-1 (Tyr632) and Akt (Ser473) in knockdown cells was significantly 1.55- and 1.86-fold,
respectively, greater than the controls. In the presence of palmitate, insulin dependent glucose uptake was significantly
about 3-fold higher in PTP-1B knockdown stable C2C12 cells compared to the control cells. Our data showed that decreasing
the PTP-1B protein level by shRNA can enhance the activity of important elements of insulin signaling. The improvement in
insulin action persisted even in palmitate treated insulin resistant myotubes. 相似文献
10.
Salar Bakhtiyari Motahareh Zaherara Karimeh Haghani Mehrdad Khatami Ali Rashidinejad 《Lipids》2019,54(2-3):141-148
In the current investigation, the effect of epigallocatechin gallate (EGCG) on the phosphorylation of IRS1S307 and AktS473 molecules in insulin-resistant C2C12 muscle cells induced with palmitate was studied and compared with the effect of the antidiabetic drug, rosiglitazone. C2C12 myoblasts were cultured in Dulbecco's modified Eagle's medium and differentiated into myotubes using horse serum and the creatine kinase test was used to confirm their differentiation. The treatment of C2C12 myotubes was carried out with palmitate, where albumin was used as the conjugator. The Western blot technique was used to check the useful phosphorylation of IRS1S307 and AktS473 in C2C12 myotubes, in the presence or absence of palmitate. There was a significant (p < 0.00) and linear increase in the activity of creatine kinase over time (0 to 96 h after differentiation) with everyday myoblast formation. While neither EGCG nor rosiglitazone showed a significant (p > 0.05) effect on palmitate content during 96 h of incubation of IRS1S307, EGCG alone or combined with rosiglitazone increased the phosphorylation of AktS473, leading to the increase of glucose uptake into C2C12 cells. Thus, it can be concluded that EGCG alone or in combination with rosiglitazone may show some therapeutic effects for the prevention or treatment of Type 2 diabetes owing to its substantial effect on increasing the phosphorylation of AktS473 and the subsequent glucose uptake into the cells. 相似文献