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      • A Survey of Application Layer Protocols of Internet of Things

        bibi, Nawab,Iqbal, Faiza,Akhtar, Salwa Muhammad,Anwar, Rabia,bibi, Shamshad International Journal of Computer ScienceNetwork S 2021 International journal of computer science and netw Vol.21 No.11

        The technological advancements of the last two decades directed the era of the Internet of Things (IoT). IoT enables billions of devices to connect through the internet and share their information and resources on a global level. These devices can be anything, from smartphones to embedded sensors. The main purpose of IoT is to make devices capable of achieving the desired goal with minimal to no human intervention. Although it hascome as a social and economic blessing, it still brought forward many security risks. This paper focuses on providing a survey of the most commonly used application layer protocols in the IoT domain, namely, Constrained Application Protocol (CoAP), Message Queuing Telemetry Transport (MQTT), Advanced Message Queuing Protocol (AMQP), and Extensible Messaging and Presence Protocol (XMPP). MQTT, AMQP, and XMPP use TCP for device-to-device communication, while CoAP utilizes UDP to achieve this purpose. MQTT and AMQP are based on a publish/subscribe model, CoAP uses the request/reply model for its structuring. In addition to this, the quality of service provision of MQTT, AMQP, and CoAP is not very high, especially when the deliverance of messages is concerned. The selection of protocols for each application is very a tedious task.This survey discusses the architectures, advantages, disadvantages, and applications of each of these protocols. The main contribution of this work is to describe each of the aforementioned application protocols in detail as well as providing their thorough comparative analysis. This survey will be helpful to the developers in selecting the protocol ideal for their system and/or application.

      • KCI등재

        Effects of Omeprazole and Caffeine Alone and in Combination with Gentamicin and Ciprofloxacin Against Antibiotic Resistant Staphylococcus Aureus and Escherichia Coli Strains

        Bibi Sedigheh Fazly Bazzaz,Mahmoud Fakori,Bahman Khameneh,Hossein Hosseinzadeh 대한약침학회 2019 Journal of pharmacopuncture Vol.22 No.1

        Objective: Antibiotic resistance is a global health problem and threatens health of societies. These problems have led to a search for alternative approaches such as combination therapy. The aim of the present study was to investigate the effect of caffeine and omeprazole in combination with gentamicin or ciprofloxacin against standard and clinically resistant isolates of Staphylococcus aureus and Escherichia coli. Methods: The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of different agents against bacterial strains were determined. The interaction of non- antibiotic drugs with gentamicin and ciprofloxacin was studied in vitro using a checkerboard method and calculating fraction inhibitory concentration index (FICI). Verapamil as ef-flux pump inhibitor was used to evaluate the possible mechanism of bacterial resistance to antibiotics. Results: The MIC and MBC values of gentamicin against bacterial strains were in the range of 20- 80 μg/ml and 40-200 μg/ml, respectively. Caffeine and omeprazole had no intrinsic inhibitory activity against tested microorganisms. However, upon combination of caffeine with antibiotics, the synergistic effects were observed. Verapamil was able to reduce the MIC values of gentamicin (4 folds) only in some bacterial strains. Conclusion: These findings indicated that caffeine was effective in removing bacterial infection caused by S. aureus and E. coli. The relevant mechanisms of antibiotic resistance were not related to the drug efflux.

      • <i>Labrenzia suaedae</i> sp. nov., a marine bacterium isolated from a halophyte, and emended description of the genus <i>Labrenzia</i>

        Bibi, Fehmida,Jeong, Jae Heon,Chung, Eu Jin,Jeon, Che Ok,Chung, Young Ryun International Union of Microbiological Societies 2014 International journal of systematic and evolutiona Vol.64 No.4

        <P>An endophytic, Gram-staining-negative bacterium was isolated from sterilized roots of a plant, <I>Suaeda maritima</I>, growing on tidal flats. Cells of the strain were motile by means of a single polar flagellum and colonies were pigmented light brown. Strain YC6927<SUP>T</SUP> was able to grow at 15–37 °C (optimum at 28–30 °C) and at pH 5.0–10.0 (optimum at pH 7.0–8.0). The strain was able to grow at NaCl concentrations of 0–9.0 % (w/v), with optimum growth at 0–5.0 % NaCl. Comparison of 16S rRNA gene sequences showed that the strain was a member of the genus <I>Labrenzia</I>, exhibiting the highest similarity to <I>Labrenzia marina</I> mano18<SUP>T</SUP> (97.6 % sequence similarity). Strain YC6927<SUP>T</SUP> produced light-brown carotenoid pigments. The major respiratory quinone was Q-10 and the DNA G+C content was 58.5 mol%. The DNA–DNA relatedness between strain YC6927<SUP>T</SUP> and closely related strains was between 8.2±1.8 and 20.3±1.5 %. Strain YC6927<SUP>T</SUP> contained summed feature 8 (C<SUB>18 : 1</SUB>ω7<I>c</I> and/or C<SUB>18 : 1</SUB>ω6<I>c</I>) and C<SUB>14 : 0</SUB> 3-OH as major fatty acids, confirming the affiliation of the strain with the genus <I>Labrenzia</I>. The polar lipids consisted of phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, phosphatidylmonomethylethanolamine, an unknown aminolipid, an unknown phospholipid and five unknown lipids. On the basis of phylogenetic analysis, physiological and biochemical characterization and DNA–DNA hybridization data, strain YC6927<SUP>T</SUP> should be assigned to a novel species of the genus <I>Labrenzia</I>, for which the name <I>Labrenzia suaedae</I> sp. nov. is proposed. The type strain is YC6927<SUP>T</SUP> ( = KACC 13772<SUP>T</SUP> = DSM 22153<SUP>T</SUP>). An emended description of the genus <I>Labrenzia</I> is also proposed.</P>

      • SCIEKCI등재

        Diversity and Characterization of Endophytic Bacteria Associated with Tidal Flat Plants and their Antagonistic Effects on Oomycetous Plant Pathogens

        Bibi, Fehmida,Yasir, Muhammad,Song, Geun-Cheol,Lee, Sang-Yeol,Chung, Young-Ryun The Korean Society of Plant Pathology 2012 Plant Pathology Journal Vol.28 No.1

        Endophytic bacterial communities of tidal flat plants antagonistic to oomycete plant pathogens were studied by the isolation of 256 root colonizing endophytic bacteria from surface-disinfected root tissues of six plants ($Rosa$ $rugosa$, $Suaeda$ $maritima$, $Vitex$ $rotundifolia$, $Carex$ $scabrifolia$, $Glehnia$ $littoralis$ and $Elymus$ $mollis$) growing in a tidal flat area of Namhae Island, Korea. To understand the antagonistic potential, an $in$ $vitro$ antagonistic assay was performed to characterize and identify strains that were antagonistic to the oomycete plant pathogens $Phytophthora$ $capsici$ and $Pythium$ $ultimum$ from the total population. Nine percent of the total number of isolated bacteria exhibited in vitro inhibitory activity against target plant pathogenic oomycetes. Taxonomic and phylogenetic placement of the antagonistic bacteria was investigated by analysis of the 16S rRNA gene sequences. The sequence analysis classified the antagonistic strains into four major classes of the domain bacteria ($Firmicutes$, ${\alpha}-Proteobacteria$, ${\gamma}-Proteobacteria$ and $Actinomycetes$) and 10 different genera. Further production of secondary metabolites, hydrolytic enzymes and plant growth promoting traits were determined for the putative new species of antagonistic endophytic bacteria. These new strains could not be identified as known species of ${\alpha}-Proteobacteria$, and so may represent novel bacterial taxa. The unexpected high antagonistic bacterial diversity associated with the tidal flat plants may be indicative of their importance in tidal flat plants as a promising source of novel antimicrobial compounds and biocontrol agents.

      • KCI등재

        Effect of Catechins, Green tea Extract and Methylxanthines in Combination with Gentamicin Against Staphylococcus aureus and Pseudomonas aeruginosa - Combination therapy against resistant bacteria -

        Bibi Sedigheh Fazly Bazzaz,Sahar Sarabandi,Bahman Khameneh,Hossein Hosseinzadeh 대한약침학회 2016 Journal of pharmacopuncture Vol.19 No.4

        Objectives: Bacterial resistant infections have become a global health challenge and threaten the society’s health. Thus, an urgent need exists to find ways to combat resistant pathogens. One promising approach to overcoming bacterial resistance is the use of herbal products. Green tea catechins, the major green tea polyphenols, show antimicrobial activity against resistant pathogens. The present study aimed to investigate the effect of catechins, green tea extract, and methylxanthines in combination with gentamicin against standard and clinical isolates of Staphylococcus aureus (S. aureus) and the standard strain of Pseudomonas aeruginosa (P. aeruginosa). Methods: The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) values of different agents against bacterial strains were determined. The interactions of green tea extract, epigallate catechin, epigallocatechin gallate, two types of methylxanthine, caffeine, and theophylline with gentamicin were studied in vitro by using a checkerboard method and calculating the fraction inhibitory concentration index (FICI). Results: The MICs of gentamicin against bacterial strains were in the range of 0.312 - 320 μg/mL. The MIC values of both types of catechins were 62.5 - 250 μg/ mL. Green tea extract showed insufficient antibacterial activity when used alone. Methylxanthines had no intrinsic inhibitory activity against any of the bacterial strains tested. When green tea extract and catechins were combined with gentamicin, the MIC values of gentamicin against the standard strains and a clinical isolate were reduced, and synergistic activities were observed (FICI < 1). A combination of caffeine with gentamicin did not alter the MIC values of gentamicin. Conclusion: The results of the present study revealed that green tea extract and catechins potentiated the antimicrobial action of gentamicin against some clinical isolates of S. aureus and standard P. aeruginosa strains. Therefore, combinations of gentamicin with these natural compounds might be a promising approach to combat microbial resistance.

      • SCIESCOPUSKCI등재

        CONSISTENT AND ASYMPTOTICALLY NORMAL ESTIMATORS FOR PERIODIC BILINEAR MODELS

        Bibi, Abdelouahab,Gautier, Antony Korean Mathematical Society 2010 대한수학회보 Vol.47 No.5

        In this paper, a distribution free approach to the parameter estimation of a simple bilinear model with periodic coefficients is presented. The proposed method relies on minimum distance estimator based on the autocovariances of the squared process. Consistency and asymptotic normality of the estimator, as well as hypotheses testing, are derived. Numerical experiments on simulated data sets are presented to highlight the theoretical results.

      • KCI등재

        The Relaxant Activity of Safranal in Isolated Rat Aortas is Mediated Predominantly via an Endothelium-Independent Mechanism - Vasodilatory mechanism of safranal -

        Bibi Marjan Razavi,Mojtaba Alipoor Amanloo,Mohsen Imenshahidi,Hossein Hosseinzadeh 대한약침학회 2016 Journal of pharmacopuncture Vol.19 No.4

        Objectives: Safranal is a pharmacologically active component of saffron and is responsible for the unique aroma of saffron. The hypotensive effect of safranal has been shown in previous studies. This study evaluates the mechanism for the vasodilatory effects induced by safranal on isolated rat aortas. Methods: To study the vasodilatory effects of safranal (0.2, 0.4 and 0.8 mM), we contracted isolated rat thoracic aorta rings by using 10-6-M phenylephrine (PE) or 80-mM KCl. Dimethyl sulfoxide (DMSO) was used as a control. The vasodilatory effect of safranal was also evaluated both on intact and denuded endothelium aortic rings. Furthermore, to study the role of nitric oxide and prostacyclin in the relaxation induced by safranal, we incubated the aortic rings by using L-NAME (10-6 M) or indomethacin (10-5 M), each for 20 minutes. Results: Safranal induced relaxation in endothelium- intact aortic rings precontracted by using PE or KCl in a concentration-dependent manner, with a maximum relaxation of more than 100%. The relaxant activity of safranal was not eliminated by incubating the aortic rings with L-NAME (EC50 = 0.29 vs. EC50 = 0.43) or with indomethacin (EC50 = 0.29 vs. EC50 = 0.35), where EC50 is the half maximal effective concentration. Also, the vasodilatory activity of safranal was not modified by endothelial removal. Conclusion: This study indicated that relaxant activity of safranal is mediated predominantly through an endothelium- independent mechanism.

      • KCI등재
      • KCI등재

        Fumigant toxicity of essential oil from Vitex pseudo-negundo against Tribolium castaneum (Herbst) and Sitophilus oryzae (L.)

        Bibi Zahra Sahaf,Saeid Moharramipour,Mohammad Hadi Meshkatalsadat 한국응용곤충학회 2008 Journal of Asia-Pacific Entomology Vol.11 No.4

        The objective of the current study was to determine the chemical constituents and fumigant toxicity of an essential oil that was isolated via hydrodistillation from dry leaves of Vitex pseudo-negundo (Hausskn.) Hand.-Mzz. The chemical composition of the essential oil was assessed via GC and GC-MS. 1, 8-Cineol (18.23%), α-Pinene (16.20%) and Sabinene (5.67%) were determined to be the major constituents of the oil. The fumigant toxicity of the essential oil was tested against 1–7 day-old adults of Tribolium castaneum (Herbst) and Sitophilus oryzae (L.) at 27±1 °C and 60±5% r.h. in darkness. The mortality of adults was tested at different concentrations ranging from 37.0 to 925.9 μL/L air and different exposure times (1–30 h). The results demonstrated that the mortality increased with increases in concentration and exposure time. At concentrations higher than 185.2 μL/L air, the mortality was recorded at more than 50% after 10 h, and reached 100% after 12–16 h. Data probit analysis demonstrated that S. oryzae (LC50=31.96 μL/L air) was more susceptible than T. castaneum (LC50= 47.27 μL/L air). These results showed that the essential oil from V. pseudo-negundo could be applicable to the management of populations of stored-product insects. The objective of the current study was to determine the chemical constituents and fumigant toxicity of an essential oil that was isolated via hydrodistillation from dry leaves of Vitex pseudo-negundo (Hausskn.) Hand.-Mzz. The chemical composition of the essential oil was assessed via GC and GC-MS. 1, 8-Cineol (18.23%), α-Pinene (16.20%) and Sabinene (5.67%) were determined to be the major constituents of the oil. The fumigant toxicity of the essential oil was tested against 1–7 day-old adults of Tribolium castaneum (Herbst) and Sitophilus oryzae (L.) at 27±1 °C and 60±5% r.h. in darkness. The mortality of adults was tested at different concentrations ranging from 37.0 to 925.9 μL/L air and different exposure times (1–30 h). The results demonstrated that the mortality increased with increases in concentration and exposure time. At concentrations higher than 185.2 μL/L air, the mortality was recorded at more than 50% after 10 h, and reached 100% after 12–16 h. Data probit analysis demonstrated that S. oryzae (LC50=31.96 μL/L air) was more susceptible than T. castaneum (LC50= 47.27 μL/L air). These results showed that the essential oil from V. pseudo-negundo could be applicable to the management of populations of stored-product insects.

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