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排序方式: 共有1310条查询结果,搜索用时 15 毫秒
61.
Vivek K. Bajpai Ajay Sharma Kwang‐Hyun Baek 《International Journal of Food Science & Technology》2013,48(11):2300-2305
This study investigated the antibacterial mechanism of action of the seed essential oil of Eleutherococcus senticosus (ESEO) against foodborne pathogenic bacteria. Preliminarily, the ESEO (1000 μg disc?1) showed potential antibacterial effect as diameter of inhibition zones (12.0 ± 0.2–37.0 ± 2.0 mm) against the tested foodborne pathogens. The MIC and MBC values of ESEO against the tested bacteria were found in the range of 125–500 and 500–1000 μg mL?1, respectively. At MIC concentration, the ESEO had potential inhibitory effect on the cell viability of the tested pathogens. In addition, SEM analysis showed the inhibitory effect of ESEO as confirmed by considerable morphological alterations on the cell wall of B. cereus ATCC 13061 and E. coli O157:H7 ATCC 43889. Moreover, the ESEO revealed its mode of action against foodborne pathogens on membrane integrity as confirmed by release of extracellular ATP, 260‐nm absorbing materials and leakage of potassium ions. These findings confirm that the ESEO can be used as a potential antibacterial agent in food industry to inhibit the growth of various foodborne pathogens. 相似文献
62.
A life cycle assessment (LCA) of one proposed method of hydrogen production – thermochemical water-splitting using the sulfur–iodine cycle couple with a very high-temperature nuclear reactor – is presented in this paper. Thermochemical water-splitting theoretically offers a higher overall efficiency than high-temperature electrolysis of water because heat from the nuclear reactor is provided directly to the hydrogen generation process, instead of using the intermediate step of generating electricity. The primary heat source for the S–I cycle is an advanced nuclear reactor operating at temperatures corresponding to those required by the sulfur–iodine process. This LCA examines the environmental impact of the combined advanced nuclear and hydrogen generation plants and focuses on quantifying the emissions of carbon dioxide per kilogram of hydrogen produced. The results are presented in terms of global warming potential (GWP). The GWP of the system is 2500 g carbon dioxide-equivalent (CO2-eq) per kilogram of hydrogen produced. The GWP of this process is approximately one-sixth of that for hydrogen production by steam reforming of natural gas, and is comparable to producing hydrogen from wind- or hydro-electric conventional electrolysis. 相似文献
63.
The problem of video classification can be viewed as discovering the signature patterns in the elemental features of a video
class. In order to solve this problem, a large and diverse set of video features is proposed in this paper. The contributions
of the paper further lie in dealing with high-dimensionality induced by the feature space and in presenting an algorithm based
on two-phase grid searching for automatic parameter selection for support vector machine (SVM). The framework thus is directed
to bridge the gap between low-level features and semantic video classes. The experimental results and comparison with state-of-the-art
learning tools on more than 5000 video segments show the effectiveness of our approach. 相似文献
64.
In field environments it is not usually possible to provide robots in advance with valid geometric models of its task and
environment. The robot or robot teams need to create these models by scanning the environment with its sensors. Here, an information-based
iterative algorithm to plan the robot's visual exploration strategy is proposed to enable it to most efficiently build 3D
models of its environment and task. The method assumes mobile robot (or vehicle) with vision sensors mounted at a manipulator
end-effector (eye-in-hand system). This algorithm efficiently repositions the systems' sensing agents using an information
theoretic approach and fuses sensory information using physical models to yield a geometrically consistent environment map.
This is achieved by utilizing a metric derived from Shannon's information theory to determine optimal sensing poses for the
agent(s) mapping a highly unstructured environment. This map is then distributed among the agents using an information-based
relevant data reduction scheme. This method is particularly well suited to unstructured environments, where sensor uncertainty
is significant. Issues addressed include model-based multiple sensor data fusion, and uncertainty and vehicle suspension motion
compensation. Simulation results show the effectiveness of this algorithm. 相似文献
65.
66.
A new technique for the modification of PAN fibers has evolved, in which the starting precursor material is impregnated with an aliphatic carboxylic acid, as well as KMnO4. The bimodification of PAN, attempted by us for the first time, is aimed at achieving dual advantages in plasticization effect, as well as in a catalytic effect in a single treatment. The unmodified, unimodified, and bimodified precursors have been characterized for their mechanical, thermal, and physical behavior during various stages of processing to carbon fibers. These results are discussed in detail. The study further shows an 18% improvement in the mechanical properties of carbon fibers, prepared from bimodified precursor, as compared to that of unmodified precursor. One of the reasons for such improvement is the lowering in diameter of PAN fibers and in the resulting carbon fibers. © 1993 John Wiley & Sons, Inc. 相似文献
67.
A method for the determination of the interfacial bond strength in well-aligned short glass fibre-reinforced polypropylene samples is discussed. The method takes into account the variation of the interfacial shear stress during the deformation process; consequently, it yields very consistent results at all values of the composite strain. The influence of the fibre orientation with respect to the load axis is appropriately considered using macro-mechanical analyses for stiffness and strength of the composite. The method is compared with two other methods reported in the literature. 相似文献
68.
The effectiveness of purines and purine analogues as inducers of erythroid differentiation in cultured murine erythroleukemia cells has been investigated. These cell lines have previously been shown to differentiate in vitro in response to dimethylsulfoxide (DMSO) and a number of other polar solvents. Two purine analogues, 6-thioguanine and 6-mercaptopurine, as well as the naturally occuring purine, purine, hypoxanthine, are shown to be extremely potent inducers. 6-Thioguanine is effective at a concentration of 0.06 mM, 750 fold lower than the DMSO concentration required for equivalent induction. 6-Mercaptopurine and hypoxanthine are effective inducers at a concentration of approximately 2 mM. Accumulation of globin mRNA was monitored during induction with purine inducers and shown to be similar in amount to globin mRNA levels reached in DMSO-induced cultures. Induction of differentiation by all three compounds follows a similar time course to induction with DMSO. All three compounds are potent inducers of HGPRT (hypoxanthine-guanine phosphoribosyltransferase)-negative cell lines; hence incorporation of purines into DNA is not required for induction of differentiation. Comparison of these compounds with other purines and purine analogues suggests a high degree of specificity in their interaction with a cellular target. 相似文献
69.
The effect of radio frequency (RF) cooking, on the quality (colour, water holding capacity, texture), heating rate, and temperature history of three types of meat products (ground, comminuted and muscle), was investigated after heating to centre temperature of 72?°C in a 1.5 kW RF heater operating at 27.12 MHz. The results were compared with that obtained from heating in a water bath. RF cooking of processed meat products resulted in a decreased cooking time (5.83, 13.5, and 13.25 min for ground beef, comminuted meat, and muscle, respectively compared to 151, 130, and 109 min in water bath), lower juice losses, acceptable colour, water holding capacity and texture. The results indicate that when using RF, ground beef has the highest power efficiency (60.17%) followed by comminuted meat (44.41%), and muscle (43.38%). However, the texture of ground beef was too chewy and elastic. The muscle's colour was inferior. The comminuted and muscle meat products exhibited average energy efficiency with improved texture. The comminuted meat displayed a large cross-sectional temperature differential, possible due to uneven salt distribution. The well mixed comminuted and ground meat products appeared to be most promising for RF cooking. 相似文献
70.
Mittal Vijay A.; Tessner Kevin D.; Trottman Hanan D.; Esterberg Michelle; Dhruv Shivali H.; Simeonova Diana I.; McMillan Amanda L.; Murphy Erin; Saczawa Mary E.; Walker Elaine F. 《Canadian Metallurgical Quarterly》2007,116(2):260
The link between movement abnormalities and psychotic disorders is presumed to reflect common neural mechanisms that influence both motor functions and vulnerability to psychosis. The prodromal period leading to psychotic disorders represents both a viable point for intervention and a developmental period that, if studied, could shed light on etiology; however, no published studies have examined the temporal progression of this link. A group with high levels of prodromal symptomatology (i.e., adolescents with schizotypal personality disorder [SPD]; n = 42) and both psychiatric controls (with other personality disorders or conduct disorder [OD]; n = 30) and nonpsychiatric controls ([NC]; n = 49) were recruited. Videotapes of structured psychiatric interviews were coded for movement abnormalities by raters blind to participants' diagnostic status, and follow-up assessments were conducted 1 year later. Controlling for psychotropic medications, the authors found that adolescents with SPD exhibited significantly more motor abnormalities in the face and upper body than did OD and NC controls. At baseline, movement abnormalities were positively correlated with the severity of positive, negative, and total prodromal symptoms. Within the SPD group, baseline movement abnormalities predicted symptom severity 1 year later. Movement abnormalities represent an early risk indicator that may be predictive of later symptom severity and potentially of psychosis onset. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献