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11.
Yugal Kishore Mohanta Sameer Kumar Singdevsachan Umesh Kumar Parida Sujogya Kumar Panda Tapan Kumar Mohanta Hanhong Bae 《IET nanobiotechnology / IET》2016,10(4):184
In the present study, green synthesis and cost effective approach of silver nanoparticles using wild medicinal mushroom Ganoderma applanatum (Pers.) Pat. from Similipal Biosphere Reserve, Odisha, India is reported. The biosynthesised AgNPs were characterised using UV‐visible spectroscopy, particle analyser and scanning electron microscopy studies. It was found by dynamic light scattering analysis, that the average size and charges of the AgNPs were 133.0 ± 0.361 nm and −6.01 ± 5.30 mV, respectively. Moreover, the Fourier transform infrared study was also conducted to identify the biomolecules or functional groups responsible for the reduction of Ag and stabilisation of the AgNPs. The potential biomedical application with reference to antimicrobial activity of the synthesised AgNPs was investigated against some pathogenic microorganisms viz. Escherichia coli, Bacillus subtilis, Staphylococcus epidermidis, Vibrio cholerae, Staphylococcus aureus and Shigella flexneri.Inspec keywords: antibacterial activity, biomedical materials, nanomedicine, nanofabrication, materials preparation, ultraviolet spectra, visible spectra, scanning electron microscopy, Fourier transform infrared spectra, molecular biophysics, reduction (chemical), biochemistry, microorganisms, silver, nanoparticlesOther keywords: green synthesis, antimicrobial activity, silver nanoparticles, wild medicinal mushroom, Ganoderma applanatum Pat, Similipal Biosphere Reserve, Odisha, UV‐visible spectroscopy, particle analyser, scanning electron microscopy, dynamic light scattering analysis, Fourier transform infrared study, biomolecules, functional groups, silver reduction, AgNP stabilisation, biomedical application, pathogenic microorganisms, Escherichia coli, Bacillus subtilis, Staphylococcus epidermidis, Vibrio cholerae, Staphylococcus aureus, Shigella flexneri, Ag
Abbreviations
- AgNPs
- ‐ Silver Nanoparticles
- SPR
- ‐Surface plasmon resonance
- AgNO3
- ‐Silver nitrate
- nm
- ‐ Nanometer
- mm
- ‐Milimetre
12.
Antiaflatoxigenic and antioxidant activity of an essential oil from Ageratum conyzoides L. 总被引:1,自引:0,他引:1
Rajaram P Patil Mansingraj S Nimbalkar Umesh U Jadhav Vishal V Dawkar Sanjay P Govindwar 《Journal of the science of food and agriculture》2010,90(4):608-614
BACKGROUND: Aflatoxin contamination of various commodities can occur as a result of infection, mainly by Aspergillus flavus and Aspergillus parasiticus. Every year, almost 25% of the world's food supply is contaminated by mycotoxins. Aflatoxins B1, B2, G1 and G2, which occur naturally, are significant contaminants of a wide variety of commodities. A number of biological activities have been associated with Ageratum conyzoides. We have therefore investigated the antiaflatoxigenic, antioxidant and antimicrobial activity of essential oils of A. conyzoides. This could help to turn A. conyzoides, a nuisance weed, into a resource. RESULTS: The essential oil of Ageratum conyzoides L. shows the presence of 12 compounds when analyzed by gas chromatography–mass spectrometry. The growth and aflatoxin production of the toxigenic strain Aspergillus parasiticus was completely inhibited by essential oil. All the studied concentrations of the oil demonstrate a reduction in mycelia growth and decreased production of different aflatoxins in fungi, as revealed by liquid chomatographic–tandem mass spectrometric analysis. Volatiles from macerated green leaf tissue of A. conyzoides were also effective against A. parasiticus. The strongest antibacterial activity was observed against the bacteria Staphylococcus aureus and Bacillus subtilis in a disk diffusion bioassay. Essential oil and methanol extract of A. conyzoides L. were assayed for their antioxidant activity. Methanol extract showed the highest antioxidant activity in FRAP and DPPH assay, whereas essential oil showed greater lipid peroxidation inhibition than methanol extract. CONCLUSION: The plant's ethno‐medicinal importance, antioxidant potential, inhibitory activity against the Aspergillus group of fungi and production of aflatoxins may add a new dimension to its usefulness in the protection of stored product. Copyright © 2010 Society of Chemical Industry 相似文献
13.
Tammy Ben-Yaacov Tommy Ive Chris G. Van de Walle Umesh K. Mishra James S. Speck Steven P. Denbaars 《Journal of Electronic Materials》2010,39(5):608-611
We investigated the properties of indium-doped zinc oxide layers grown by metalorganic chemical vapor deposition on semi-insulating
GaN(0001) templates. Specular and transparent films were grown with n-type carrier concentrations up to 1.82 × 1019 cm−3 as determined by Hall measurements, and all In-doped films had carrier concentrations significantly higher than that of a
comparable undoped film. For low In flows, the carrier concentration increased accordingly with trimethyl-indium (TMIn) flow
until a maximum carrier concentration of 1.82 × 1019 cm−3 was realized. For higher In flows, the carrier concentration decreased with increasing TMIn flow rate. Sheet resistance as
low as 185 Ω/sq was achieved for the In-doped films, which is a significant decrease from that of a comparable undoped ZnO
film. Our n-type doping studies show that In is an effective dopant for controlling the n-type conductivity of ZnO. 相似文献
14.
Necessary and sufficient condition for admissibility of a test procedure based on preliminary test of significance for life data has been obtained. 相似文献
15.
16.
Vinod Upadhyay Umesh D. Harkal Dean C. Webster Gordon P. Bierwagen 《Journal of Coatings Technology and Research》2013,10(6):865-878
The influence of structural and systematic compositional variations in glycidyl carbamate (GC) functional polymers on the electrochemical properties of their coatings was studied. There are few reports which focus on the correlation of structural and compositional variations in polymer films with their electrochemical barrier properties, diffusion properties with regards to water and aqueous electrolytes, and corrosion performance. To begin to fill this knowledge gap, two sets of GC functional polymers were studied. The polymer compositions were designed to vary the extent of polar hydrophilic groups, non-polar hydrophobic groups, and reactive epoxy groups in the final coatings. Impedance responses of the coatings were found to be closely related to the structural and compositional variations of these GC polymer films. In addition, single frequency EIS experiments were used in an attempt to understand the water uptake behavior of these polymer films using NaCl solution and ionic liquid under immersed condition. The resulting transport property data of the films was correlated to their polymer structure and composition. Moreover, a novel attempt at ranking the stability of coating using capacitance measurement during a cyclic wetting–drying condition was also attempted. The information obtained from this work can potentially be used to optimize the polymer for the specific performance properties needed in the protective coating applications, saving significant time and effort in the research and development stage. 相似文献
17.
Virginia E. Pitzer C��cile Viboud Ben A. Lopman Manish M. Patel Umesh D. Parashar Bryan T. Grenfell 《Journal of the Royal Society Interface》2011,8(64):1584-1593
Rotavirus is a major cause of mortality in developing countries, and yet the dynamics of rotavirus in such settings are poorly understood. Rotavirus is typically less seasonal in the tropics, although recent observational studies have challenged the universality of this pattern. While numerous studies have examined the association between environmental factors and rotavirus incidence, here we explore the role of intrinsic factors. By fitting a mathematical model of rotavirus transmission dynamics to published age distributions of cases from 15 countries, we obtain estimates of local transmission rates. Model-predicted patterns of seasonal incidence based solely on differences in birth rates and transmission rates are significantly correlated with those observed (Spearman''s ρ = 0.65, p < 0.05). We then examine seasonal patterns of rotavirus predicted across a range of different birth rates and transmission rates and explore how vaccination may impact these patterns. Our results suggest that the relative lack of rotavirus seasonality observed in many tropical countries may be due to the high birth rates and transmission rates typical of developing countries rather than being driven primarily by environmental conditions. While vaccination is expected to decrease the overall burden of disease, it may increase the degree of seasonal variation in the incidence of rotavirus in some settings. 相似文献
18.
Repeatability of many genetic analysis experiments can be improved by the application of signal processing and image-processing tools. Most of the experiments in genetics result in some sort of digital signal or image patterns that are subjectively analyzed by the geneticists. This paper presents an example project where image-processing techniques are applied for automation of most of the routine processes of agarose gel image analysis. Result of applying this program has shown that the time taken for the analysis has been reduced by about 70% and the result is reproducible. 相似文献
19.
1. Introduction The requirement of minimal bottom coverageand thick sidewall coverage for PVD-based films forlow via resistance and improved stress migration isnot easy to achieve with traditional depositionmethods. Modern I-PVD techniques give high bot-tom coverage, due to the ionized component of thedeposition flux. Sidewall coverage tends to be low,which is mainly due to off-normal deposition fluxand a less than unity sticking coefficient. 相似文献
20.
Umesh Deshpande Arobinda Gupta Anupam Basu 《IEEE transactions on systems, man, and cybernetics. Part B, Cybernetics》2005,35(2):345-358
The contract net protocol (CNP) is a widely used coordination mechanism in multiagent systems. It has a lot of communication overhead due to the broadcast of the task announcements. The performance of the CNP degrades drastically when the number of communicating agents and the number of tasks announced increases. Hence, it has problems of scalability. In order to overcome this limitation, an instance-based learning (IBL) mechanism is designed that uses previously stored instances in order to select a target agent. This avoids the expensive bidding process. The scheme is implemented in a simulated distributed hospital system where the CNP is used for resource sharing across hospitals. Experimental results demonstrate that with the incorporation of the IBL, the system performance improves significantly. The system is better scalable with respect to the number of tasks. 相似文献