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نویسندگان: 

ALIKHANI S. | IRANMANESH M.A. | TAHERI H.

اطلاعات دوره: 
  • سال: 

    2014
  • دوره: 

    71
  • شماره: 

    -
  • صفحات: 

    383-394
تعامل: 
  • استنادات: 

    1
  • بازدید: 

    158
  • دانلود: 

    0
کلیدواژه: 
چکیده: 

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اطلاعات دوره: 
  • سال: 

    1398
  • دوره: 

    4
  • شماره: 

    2
  • صفحات: 

    224-234
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    321
  • دانلود: 

    178
چکیده: 

امروزه شبکه های حسگر بی سیم به یکی از عناصر مهم و کلیدی در علم و صنعت تبدیل شده اند که استفاده از آنها باعث رشد کیفی و کمی در مدیریت هوشمند فرآیندها گشته است. در این میان مانند هر تکنولوژی نوپای دیگری که به عرصه علم و فناوری وارد می گردد موانعی ناخواسته بر سر راه رشد و تکامل آن قرار می گیرد که هدف پژوهشگران و محققان کاهش هرچه بیشتر و یا حتی رفع آن می باشد. یکی از اصلی ترین موانع بر سرراه توسعه و بهره برداری هرچه وسیع تر از این شبکه ها تأمین انرژی الکتریکی مورد نیاز برای گره های شبکه می باشد. در این خصوص پژوهشگران مسیرهای مختلفی را برای عبور از این مانع بکار گرفته اندکه از موفق ترین این راه کارها می توان به استفاده از پروتکل های مسیریابی هوشمند و روشهای خواب-بیداری بهینه اشاره نمود که هدف نهایی این روشها غالباً کاهش حداکثری مصرف انرژی و بالابردن راندمان شبکه می باشد. ما در این مقاله برآنیم تا با مقایسه دو پروتکلSMAC و Zigbee که در این زمینه مورد استفاده قرار می گیرند و شبیه سازی عملکرد این دو پروتکل مسیریابی در ذیل پروتکل خواب انتشار مستقیم در فضای نرم افزار NS2 راندمان این دو پروتکل مسیریابی را در یک شبکه حسگر بی سیم مدل سازی شده با یکدیگر مقایسه نماییم.

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نویسندگان: 

محمدی فرید | قرایی حسین

اطلاعات دوره: 
  • سال: 

    1396
  • دوره: 

    13
  • شماره: 

    4 (پیاپی 30)
  • صفحات: 

    109-120
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    1005
  • دانلود: 

    268
چکیده: 

حمله کرم چاله یک نوع حمله فعال می باشد که در لایه سوم شبکه از شبکه های اقتضایی رخ می دهد. در این حمله مهاجمین با متقاعد کردن گره فرستنده برای ارسال اطلاعات از یک مسیر جعلی که کوتاه تر و سریع تر از مسیر عادی به نظر می رسد، سعی دارند ارسال بسته ها از تونل ایجاد شده انجام شود تا بتوانند، حملات آنالیز ترافیک، انکار سرویس، رها کردن بسته ها و یا جلورانی انتخابی را انجام دهند. هر پروتکلی که از مقیاس کم ترین تاخیر و کم-ترین تعداد گام برای مسیریابی استفاده کند، در برابر این حمله آسیب پذیر است. در این مقاله یک راه کار جدید برای مقابله با حملات کرم چاله ارائه می-دهیم. در راه حل پیشنهادی هر گره دارای یک وزن است و مجموع وزن ها در شبکه برابر صد خواهد بود. هرگاه گره ای قصد ارسال ترافیک به گره دیگر را داشته باشد، در بسته RREQ حداقل وزن درخواستی برای ایجاد ارتباط را بیان می کند. گره فرستنده با توجه به اهمیت داده هایی که ارسال خواهد کرد مشخص می کند که مجموع وزن گره های شرکت کننده، در فرایند کشف مسیر باید چقدر باشد. روش پیشنهادی را MAODV نامگذاری می کنیم. روش فوق به صورت نرم افزاری بوده و با توجه به این که از تکنیک رمزنگاری استفاده نخواهیم کرد، پیش بینی می کنیم سربار کمتری نسبت به سایر تکنیک ها داشته باشیم، و همچنین به علت عدم استفاده از الگوریتم های سخت، توان گره ها که اتفاقا محدود است، کمتر صرف محاسبات خواهد شد. کارایی الگوریتم پیشنهادی را در محیط ns-2 نشان خواهیم داد.

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نویسندگان: 

Akbari Abed | Moghri Moazen Tahere

نشریه: 

PETROLEUM BUSINESS REVIEW

اطلاعات دوره: 
  • سال: 

    2020
  • دوره: 

    4
  • شماره: 

    1
  • صفحات: 

    1-11
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    131
  • دانلود: 

    0
چکیده: 

The pipeline project, Nord Stream 2 (NS2), has been an issue of controversies. Russia and Germany consider the project an economic contract, but the United-States and Eastern European countries have concerns about its geopolitical effects. These disputes have created a divide in Europe and have posed a threat to trans-Atlantic relations. The current research suggests NS2 can influence the strategic balance between great powers in the international system, giving energy leverage to Russia against United-States, and consequently to China by strengthening projects like the Belt and Road Initiative (BRI). Our findings put forward that not only NS2, in case of realization, is a source of American decline, but also the debates on the issue are a sign of American struggling for protecting its precarious international position. By placing Europe in front of the United-States, NS2 could be one component of European strategic autonomy (ESA); meanwhile, it may jeopardize ESA by depending on Europe on Russia. Europe’ s solution to gain ESA is to use its leverages such as normative one to manage the situation for outcomes like protecting Europe’ s unity and economic interests.

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اطلاعات دوره: 
  • سال: 

    2014
  • دوره: 

    18
  • شماره: 

    1
  • صفحات: 

    1-7
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    311
  • دانلود: 

    0
چکیده: 

Backgrounds: Most of the hepatitis C virus (HCV) infections elicit poor immune responses and 75% to 85% of cases become chronic; therefore, the development of an effective vaccine against HCV is of paramount importance. In this study, we aimed to evaluate co-administration of HCV non-Structural Protein 2 and IL-12 DNA vaccines in C57BL/6 mice.Methods: A plasmid encoding full-length HCV NS2 protein (non-structural protein 2) was generated and used to vaccinate mice. Negative control (an empty expression vector) was also employed to evaluate the background response. To investigate immune responses against vaccine, C57BL/6 mice received three doses of the vaccine with a two-week interval. Cellular immunity was assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay for lymphocyte proliferation, lactate dehydrogenase release for cytotoxic T lymphocyte (CTL) activity and cytokine assay.Results: The findings demonstrated that immunization of mice with plasmid expressing HCV NS2 induced CTL response, interferon gamma production, and lymphocyte proliferation compared to negative control. The results also demonstrated that co-administration of IL-12 with the HCV NS2 plasmid induced significantly better immune response in C57BL/6 mice.Conclusion: DNA vaccine encoding HCV NS2 is an effective candidate that can trigger CTL-based immune response against HCV. In addition, the results suggested that combining the DNA vaccine approach with immune stimulatory cytokines may significantly enhance antigen-specific immune responses.

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اطلاعات دوره: 
  • سال: 

    2020
  • دوره: 

    9
  • شماره: 

    4
  • صفحات: 

    366-373
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    194
  • دانلود: 

    0
چکیده: 

Introduction: Dengue infection is one of the worldwide problems with an increasing rate. Dengue virus (DENV) belonging to Flaviviridae family carries a positive single strand RNA, consists of four serotypes, gives rise to dengue shock syndrome, undifferentiated fever (DF), and dengue hemorrhagic fever. Unfortunately, there is no licensed drug available for various serotypes and the vaccine candidates are still under investigation. Flavonoids are a group of important phytochemicals of many plants used against various viruses. Therefore, the present study was designed to screen the subset of plant flavonoids against the DENV NS2/NS3 protease of 3L6P and 2VBC of serotype 1 and serotype 4 respectively by in silico docking. Methods: Flavonoids were subjected to docking study using AutoDock Vina. The lead molecule was further investigated for its dengue viral protease inhibition. Further the cytotoxicity of lead molecule was tested by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. Absorption, distribution, metabolism, excretion and toxicity (ADMET) study was performed using OSIRIS software. Results: The flavonoids amentoflavone, quercetin-3-O-β-D-glucopyranoside, avicularin, reynoutrin, silymarin and scutallarein showed potential interactions in both serotype 1 and serotype 4 and hence these flavonoids can be served as potential lead candidates to stop viral replication. Amentoflavone, the lead molecule, showed potential in-vitro protease inhibition activity and also the concentration was below the minimal effective level for the in-vitro cytotoxicity test conducted. Conclusion: This finding has laid the groundwork for eventual identification of these flavonoids in developing potential inhibitor candidates for further development by in-vitro extraction and chemical modification methods.

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اطلاعات دوره: 
  • سال: 

    2019
  • دوره: 

    7
  • شماره: 

    2
  • صفحات: 

    1-8
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    93
  • دانلود: 

    0
چکیده: 

Background: The Non-Structural (NS) genomic segment of influenza A virus expresses two proteins (NS1 and NS2) responsible for virulence and pathogenicity. Here, we characterize the NS gene of H1N1 influenza viruses isolated from Iranian patients during the 2015 and 2017 outbreaks. Materials and Methods: Influenza A positive specimens with high viral load were selected for virus amplification on MDCK (Madin-Darby Canine Kidney) cells to obtain sufficient viral RNA for RT-PCR. The NS segments were amplified and sequenced from randomly selected samples. Genetic characterization, phylogenetic, and protein modeling analyses were carried out using Bioedit, MEGA7 software, and Muster, Modweb, Modfold, Tm-align web servers. Reference sequences from other geographic regions were available on GenBank. Results: Phylogenetic analysis on the NS gene of A/H1N1 isolates revealed that all Iranian isolates, except the A/Tehran/SMO08/2015, were close to strains from Continental countries of Asia and North America, with 99% identity. Meanwhile the mentioned exception was clustered with some strains from Iran, Kazakhstan, Myanmar, Turkmenistan, and Jordan. Overall six substitutions were observed through the deduced Iranian NS1 and NS2 amino acid sequences. One of the mutations (the E96D mutation from the isolate A/Tehran/A7106/2017) was first observed in the present project. Prediction of three-dimensional structure of the Iranian NS1 and NS2 proteins in comparison with counterpart references available in PDB showed a slight deviation in the functional domains. However, the high similarity of the Iranian NS gene with those from other countries indicate no significant changes in the molecular features of the NS genes. Conclusion: The severity of the symptoms does not seem to be caused by the observed mutations. Molecular analysis of other alleles is needed to explain the high pathogenic feature of the 2015 isolates.

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نویسندگان: 

Khaleghi H. | Sattari A. | Azizi S. | Sharifpour I.

اطلاعات دوره: 
  • سال: 

    621
  • دوره: 

    21
  • شماره: 

    6
  • صفحات: 

    1461-1471
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    18
  • دانلود: 

    0
چکیده: 

This study evaluated the healing effect of black seed essential oil (Nigella sativa,NS) dietary supplementation on skin wound in goldfish (Carassius auratus). Some 48 goldfish were divided into 4 groups, including the control and 3 treatment groups in three replications and kept for study period of 7 days. NS essential oil was added to the basal diet of treatment groups at the concentration of 2% for the NS2 group, 4% for the NS4 group, and 6% for the NS6 group. The control group was fed the basal diet without NS during the experimental period. The 5 mm incision made by scalpel on the right flank of all fishes below the dorsal fin above the lateral line. The fish fed three times a day with assigned diet for a week. Histological investigations approved the effects of NS essential oil on skin wound healing. Diet with 6% concentration of NS6 revealed the improved healing outcomes such as re-epithelialization, muscle regeneration and scale formation rather than NS2 and NS4 groups.

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اطلاعات دوره: 
  • سال: 

    2014
  • دوره: 

    5
  • شماره: 

    1 (15)
  • صفحات: 

    13-18
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    402
  • دانلود: 

    0
چکیده: 

Wireless ad hoc networks are composed of independent nodes, managing the network without any infrastructure. The connection between nodes is provided by sending packages and by trusting to each other. Therefore, using efficient and certain protocols is the essential requirement of these networks. Due to special characteristics of wireless ad hoc networks such as lack of a fixed infrastructure, these protocols are exposed to many attacks. One of these attacks is black hole attack. In this attack, the node running this attack attracts data packages by sending a false response to source node and destroys them. In this paper, the effect of black hole attack on DSR and AODV routing protocol in wireless ad hoc network has been studied. The results simulated with NS2 simulator software show the weaknesses and advantages of these protocols when there are black hole nodes in the network.

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اطلاعات دوره: 
  • سال: 

    2014
  • دوره: 

    6
  • شماره: 

    4
  • صفحات: 

    214-227
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    315
  • دانلود: 

    0
چکیده: 

BACKGROUND Recent studies suggest that rare codon clusters are functionally important for protein activity.METHODS: Here, for the first time we analyzed and reported rare codon clusters in Hepatitis C Virus (HCV) genome and then identified the location of these rare codon clusters in the structure of HCV protein. This analysis was performed using the Sherlocc program that detects statistically relevant conserved rare codon clusters.RESULTS: By this program, we identified the rare codon cluster in three regions of HCV genome; NS2, NS3, and NS5A coding sequence of HCV genome. For further understanding of the role of these rare codon clusters, we studied the location of these rare codon clusters and critical residues in the structure of NS2, NS3 and NS5A proteins. We identified some critical residues near or within rare codon clusters. It should be mentioned that characteristics of these critical residues such as location and situation of side chains are important in assurance of the HCV life cycle.CONCLUSION: The characteristics of these residues and their relative status showed that these rare codon clusters play an important role in proper folding of these proteins.Thus, it is likely that these rare codon clusters may have an important role in the function of HCV proteins. This information is helpful in development of new avenues for vaccine and treatment protocols.

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