216 research outputs found

    Linear Protection Schemes Analysis in Scattered Placement Fiber-To-The Home-Passive Optical Network Using Customer Access Protection Unit Solution

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    <STRONG>Problem statement:</STRONG> This study highlights on restoration scheme proposed against failure in working line at the drop region for Fiber-To-The Home (FTTH) with a Passive Optical Network (PON). Whereas PON is a system that brings optical fiber cable and signals all or most of the way to the end user.<STRONG> Approach:</STRONG> Survivability scheme against failure is focused on scattered residence architectures and it is applied in the ring and tree topology respectively by means of Customer Access Protection Unit (CAPU). CAPU will be installed before the ONU and ensure the signal will find the alternative path when failure occurs at the specific line. Our proposal scheme is low cost and applicable to any residence architecture. The advantage of this scheme is the failure at fiber line can be recovered until three levels to make sure the optic signal flow continuously to avoid any application disturbance. Two type of restoration scheme is proposed by means of linear protection (tree) and migrated protection (ring). FTTH based network design is simulated by using Opti System 7.0 in order to investigate the power output and BER performance at each node in the tree and ring protection scheme in scattered placement. This study we perform an analysis on linear protection scheme that consisting of two model a) Line to Line (L2L) protection and CAPU to CAPU (C2C) or Shared protection. However the migration of tree to ring topology to enable the signal flow continuously in the case of failure occurs specifically in random or scattered placement topology has been highlighted in our previous publication. <STRONG>Results:</STRONG> The signal will be divided into section; drop and pass through and the ratio is significant to determine the number of user allowed and achievable distance. Output power for optical nodes could be slightly improved by varying the pass through and drop signal ratio. <STRONG>Conclusion:</STRONG> Our proposal is the first reported up to this time in which the upstream signal flows in anticlockwise in ring topology when the restoration scheme activated

    Photodynamic therapy and tumor imaging of hypericin-treated squamous cell carcinoma

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    BACKGROUND: Conventional cancer therapy including surgery, radiation, and chemotherapy often are physically debilitating and largely ineffective in previously treated patients with recurrent head and neck squamous cell carcinoma (SCC). A natural photochemical, hypericin, could be a less invasive method for laser photodynamic therapy (PDT) of these recurrent head and neck malignancies. Hypericin has powerful photo-oxidizing ability, tumor localization properties, and fluorescent imaging capabilities as well as minimal dark toxicity. The current study defined hypericin PDT in vitro with human SCC cells before the cells were grown as tumor transplants in nude mice and tested as a model for hypericin induced tumor fluorescence and PDT via laser fiberoptics. METHODS: SNU squamous carcinoma cells were grown in tissue culture, detached from monolayers with trypsin, and incubated with 0.1 μg to 10 μg/ml of hypericin before exposure to laser light at 514, 550, or 593 nm to define optimal dose, time, and wavelength for PDT of tumor cells. The SCC cells also were injected subcutaneously in nude mice and grown for 6–8 weeks to form tumors before hypericin injection and insertion of fiberoptics from a KTP532 surgical laser to assess the feasibility of this operating room instrument in stimulating fluorescence and PDT of tumors. RESULTS: In vitro testing revealed a hypericin dose of 0.2–0.5 μg/ml was needed for PDT of the SCC cells with an optimal tumoricidal response seen at the 593 nm light absorption maximum. In vivo tumor retention of injected hypericin was seen for 7 to10 days using KTP532 laser induced fluorescence and biweekly PDT via laser fiberoptics led to regression of SCC tumor transplants under 0.4 cm(2 )diameter, but resulted in progression of larger size tumors in the nude mice. CONCLUSION: In this preclinical study, hypericin was tested for 514–593 nm dye laser PDT of human SCC cells in vitro and for KTP532 surgical laser targeting of SCC tumors in mice. The results suggest hypericin is a potent tumor imaging agent using this surgical laser that may prove useful in defining tumor margins and possibly in sterilizing post-resection margins. Deeply penetrating pulsed infrared laser emissions will be needed for PDT of larger and more inaccessible tumors

    Anti-Malaria Drug Mefloquine Induces Motor Learning Deficits in Humans

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    Mefloquine (a marketed anti-malaria drug) prophylaxis has a high risk of causing adverse events. Interestingly, animal studies have shown that mefloquine imposes a major deficit in motor learning skills by affecting the connexin 36 gap junctions of the inferior olive. We were therefore interested in assessing whether mefloquine might induce similar effects in humans. The main aim of this study was to investigate the effect of mefloquine on olivary-related motor performance and motor learning tasks in humans. We subjected nine participants to voluntary motor timing (dart throwing task), perceptual timing (rhythm perceptual task) and reflex timing tasks (eye-blink task) before and 24 h after the intake of mefloquine. The influence of mefloquine on motor learning was assessed by subjecting participants with and without mefloquine intake (controls: n = 11 vs mefloquine: n = 8) to an eye-blink conditioning task. Voluntary motor performance, perceptual timing, and reflex blinking were not affected by mefloquine use. However, the influence of mefloquine on motor learning was substantial; both learning speed as well as learning capacity was impaired by mefloquine use. Our data suggest that mefloquine disturbs motor learning skills. This adverse effect can have clinical as well as social clinical implications for mefloquine users. Therefore, this side-effect of mefloquine should be further investigated and recognized by clinicians

    Pest categorisation of Crisicoccus seruratus

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    Following the commodity risk assessments of Acer palmatum plants grafted on A. davidii from China, in which Crisicoccus matsumotoi (Hemiptera: Pseudococcidae) was identified as a pest of possible concern, the European Commission requested the EFSA Panel on Plant Health to conduct a pest categorisation of C. matsumotoi for the territory of the European Union. Recent taxonomic revision of the genus Crisisoccus concluded that C. matsumotoi is a synonym of C. seruratus; therefore, the categorisation will use the current valid name C. seruratus. It is an insect pest native to Japan, feeding on species in 13 plant families. There are reports of its presence also in China and the Republic of Korea, but there is great uncertainty about the identity of the species for these records. Therefore, there is uncertainty about the species referred to as C. matsumotoi in the commodity risk assessments of A. palmatum. C. seruratus is a multivoltine species. It has three generations per year and overwinters as a nymph. The most important crops that may be affected by C. seruratus are figs (Ficus carica), grapes (Vitis spp.), nashi pears (Pyrus pyrifolia var. culta), persimmons (Diospyros kaki) and walnuts (Juglans regia). Plants for planting and fruits provide potential pathways for entry into the EU. Host availability and climate suitability suggest that the central, northern and some areas of southern EU countries would be suitable for the establishment of C. seruratus. The introduction of this mealybug would likely have an economic impact in the EU through yield reduction and fruit downgrading because of honeydew deposition and the consequent growth of sooty moulds. This insect is not listed in Annex II of Commission Implementing Regulation (EU) 2019/2072. Phytosanitary measures are available to reduce the likelihood of entry and spread of this species into the EU. C. seruratus satisfies the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest

    Pest categorisation of Pestalotiopsis microspora

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    Following an EFSA commodity risk assessment of bonsai plants (Pinus parviflora grafted on Pinus thunbergii) imported from China, the EFSA Plant Health Panel performed a pest categorisation of Pestalotiopsis microspora, a clearly defined plant pathogenic fungus of the family Pestalotiopsidaceae. The pathogen was reported on a wide range of monocotyledonous, dicotyledonous and gymnosperms, either cultivated or wild plant species, causing various symptoms such as leaf spot, leaf blight, scabby canker, fruit spot, pre- and post-harvest fruit rot and root rot. In addition, the fungus was reported as an endophyte on a wide range of asymptomatic plant species. This pest categorisation focuses on the hosts that are relevant for the EU and for which there is robust evidence that the pathogen was formally identified by a combination of morphology, pathogenicity and multilocus sequencing analyses. Pestalotiopsis microspora was reported in Africa, North, Central and South America, Asia and Oceania. In the EU, it was reported in the Netherlands. There is a key uncertainty on the geographical distribution of P. microspora worldwide and in the EU, because of the endophytic nature of the fungus, the lack of surveys, and because in the past, when molecular tools were not fully developed, the pathogen might have been misidentified as other Pestalotiopsis species or other members of the Pestalodiopsidaceae family based on morphology and pathogenicity tests. Pestalotiopsis microspora is not included in Commission Implementing Regulation (EU) 2019/2072. Plants for planting, fresh fruits, bark and wood of host plants as well as soil and other growing media associated with plant debris are the main pathways for the entry of the pathogen into the EU. Host availability and climate suitability in parts of the EU are favourable for the establishment and spread of the pathogen. The introduction and spread of the pathogen into the EU are expected to have an economic and environmental impact where susceptible hosts are grown. Phytosanitary measures are available to prevent the introduction and spread of the pathogen into the EU. Unless the restricted distribution in the EU is disproven, Pestalotiopsis microspora satisfies all the criteria that are within the remit of EFSA to assess for this species to be regarded as potential Union quarantine pest

    Two-Component Elements Mediate Interactions between Cytokinin and Salicylic Acid in Plant Immunity

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    Recent studies have revealed an important role for hormones in plant immunity. We are now beginning to understand the contribution of crosstalk among different hormone signaling networks to the outcome of plant–pathogen interactions. Cytokinins are plant hormones that regulate development and responses to the environment. Cytokinin signaling involves a phosphorelay circuitry similar to two-component systems used by bacteria and fungi to perceive and react to various environmental stimuli. In this study, we asked whether cytokinin and components of cytokinin signaling contribute to plant immunity. We demonstrate that cytokinin levels in Arabidopsis are important in determining the amplitude of immune responses, ultimately influencing the outcome of plant–pathogen interactions. We show that high concentrations of cytokinin lead to increased defense responses to a virulent oomycete pathogen, through a process that is dependent on salicylic acid (SA) accumulation and activation of defense gene expression. Surprisingly, treatment with lower concentrations of cytokinin results in increased susceptibility. These functions for cytokinin in plant immunity require a host phosphorelay system and are mediated in part by type-A response regulators, which act as negative regulators of basal and pathogen-induced SA–dependent gene expression. Our results support a model in which cytokinin up-regulates plant immunity via an elevation of SA–dependent defense responses and in which SA in turn feedback-inhibits cytokinin signaling. The crosstalk between cytokinin and SA signaling networks may help plants fine-tune defense responses against pathogens
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