13,790 research outputs found
Performance evaluation for high speed vehicle in VANET
Vehicular Ad hoc Networks (VANETs) is a high dynamic emerging technology for supporting wireless communication among vehicles. Communication via routing packets over the high-speed vehicles is a challenging task. Vehicles mobility speed can varies depending on the road specification. However in highways speed can be increased up to 120 â 200 Km/hr. moving in high speed can affect the efficiency of data delivery. In particular V2I traffic where moving car trying to deliver data to fixed space units which are designed to collected and process data from vehicles. In this paper, we investigated the consequences on increasing vehicle mobility speed in term of data delivery evaluation metrics including network throughput, delay and packet delivery ration. Results shows that in high speed mobility VANET, network throughput it decreased, and packet delivery ration is decreased as well
Forecast of Total Electron Content over Europe for disturbed ionospheric Conditions
A general picture of the occurrence of ionospheric storms as function of local time, season
and location is known from numerous studies over the past 50 years. Nevertheless, it is not
yet possible to say how the ionosphere will actually respond to a given space weather event
because the measurements of the onset time, location of maximum perturbation, amplitude
and type of storm (positive or negative) deviate much from the climatology. However, statistical
analyses of numerous storm events observed in the Total Electron Content (TEC) since 1995
enable to estimate and predict a most probable upcoming perturbed TEC over Europe based
on forecasts of geomagnetic activity. A first approach will be presented here. The forecast of
perturbed TEC is part of the Forecast System Ionosphere build under the umbrella of the FP7
project AFFECTSâ (Advanced Forecast For Ensuring Communication Through Space). It aims
to help users mitigating the impact on communication system
Nanotoxicity of polyelectrolyte-functionalized titania nanoparticles towards microalgae and yeast: Role of the particle concentration, size and surface charge
We studied the nanotoxicity of titania nanoparticles (TiOâNPs) of various hydrodynamic diameters and crystallite sizes towards C. reinhardtii microalgae and S. cerevisiae (yeast) upon illumination with UV and visible light. The cell viability was assessed for a range of nanoparticle concentrations and incubation times. We found that bare TiOâNPs affect the C. reinhardtii cell viability at much lower particle concentrations than for yeast. We observed an increase of the TiOâNPs toxicity upon illumination with UV light compared with that in dark conditions due to the oxidative stress of the produced reactive oxygen species. We also found an increased TiOâNPs nanotoxicity upon illumination with visible light which indicates that they may also interfere with the microalgae's photosynthetic system leading to decreased chlorophyll content upon exposure to TiOâNPs. The results indicate that the larger the hydrodynamic diameter of the TiOâNPs the lower is their nanotoxicity, with anatase TiOâNPs generally being more toxic than rutile TiOâNPs. We also prepared a range of polyelectrolyte-coated TiOâNPs using a layer by-layer method and studied their nanotoxicity towards yeast and microalgae. We found that the toxicity of the coated TiOâNPs changes with their surface charge. TiOâNPs coated with cationic polyelectrolyte as an outer layer exhibit much higher nanotoxicity than the ones with an outer layer of anionic polyelectrolyte. TEM images of sectioned microalgae and yeast cells exposed to different polyelectrolyte-coated TiOâNPs confirmed the formation of a significant build-up of nanoparticles on the cell surface for bare and cationic polyelectrolyte-coated TiOâNPs. The effect comes from the increased adhesion of cationic nanoparticles to the cell walls. Significantly, coating the TiOâNPs with anionic polyelectrolyte as an outer layer led to a reduced adhesion and much lower nanotoxicity due to electrostatic repulsion with the cell walls. This suggest a new way of making cationic TiOâNPs safer for use in different formulations by pre-coating them with anionic polyelectrolytes. The results of this study give important insights into the various factors controlling the nanotoxicity of TiOâNPs
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Matrix Metalloproteinases and Glaucoma Treatment.
Matrix metalloproteinases (MMPs) are a family of proteolytic enzymes that degrade extracellular matrix (ECM) components such as collagen and have important roles in multiple biological processes, including development and tissue remodeling, both in health and disease. The activity of MMPs is influenced by the expression of MMPs and tissue inhibitors of metalloproteinase (TIMPs). In the eye, MMP-mediated ECM turnover in the juxtacanalicular region of the trabecular meshwork (TM) reduces outflow resistance in the conventional outflow pathway and helps maintain intraocular pressure (IOP) homeostasis. An imbalance in the MMP/TIMP ratio may be involved in the elevated IOP often associated with glaucoma. The prostaglandin analog/prostamide (PGA) class of topical ocular hypotensive medications used in glaucoma treatment reduces IOP by increasing outflow through both conventional and unconventional (uveoscleral) outflow pathways. Evidence from in vivo and in vitro studies using animal models and anterior segment explant and cell cultures indicates that the mechanism of IOP lowering by PGAs involves increased MMP expression in the TM and ciliary body, leading to tissue remodeling that enhances conventional and unconventional outflow. PGA effects on MMP expression are dependent on the identity and concentration of the PGA. An intracameral sustained-release PGA implant (Bimatoprost SR) in development for glaucoma treatment can reduce IOP for many months after expected intraocular drug bioavailability. We hypothesize that the higher concentrations of bimatoprost achieved in ocular outflow tissues with the implant produce greater MMP upregulation and more extensive, sustained MMP-mediated target tissue remodeling, providing an extended duration of effect
Community Knowledge, Perceptions, and Practices Associated with Urogenital Schistosomiasis among School-Aged Children in Zanzibar, United Republic of Tanzania
Background: On the Zanzibar islands, United Republic of Tanzania, elimination of urogenital schistosomiasis is strived for in the coming years. This qualitative study aimed to better understand community knowledge, perceptions, and practices associated with schistosomiasis among school-aged children on Unguja and Pemba islands, in order to inform the development of behavior change interventions contributing to eliminate urogenital schistosomiasis.
Methodology: In 2011, we conducted 35 childrenâs discussion groups, 41 in-depth interviews with parents and teachers, and 5 focus group discussions with community members in Zanzibar. Using a modified-grounded theory approach, we transcribed and coded the narrative data followed by thematic analysis of the emergent themes.
Principal Findings: Urogenital schistosomiasis is a common experience among children in Zanzibar and typically considered a boysâ disease. Children engage in multiple high-risk behaviors for acquiring schistosomiasis because of poor knowledge on disease transmission, lack of understanding on severity of disease-associated consequences, and lack of alternative options for water related activities of daily living and recreational play. Local primary school teachers had little to no training about the disease and no teaching tools or materials for students.
Conclusions/Significance: Conducting activities in open natural freshwater contaminated by S. haematobium larvae compromises the health of school-aged children in Zanzibar. The perception of urogenital schistosomiasis as a minor illness rather than a serious threat to a childâs well-being contributes to the spread of disease. Understanding community perceptions of disease along with the barriers and facilitators to risk reduction behaviors among children can inform health promotion activities, campaigns, and programs for the prevention, control, and elimination of urogenital schistosomiasis in Zanzibar
SERUM PROLACTIN LEVELS IN TYPE-II DIABETES MELLITUS WITH RETINOPATHY PATIENTS IN AND AROUND HYDERABAD
Background & Objectives: Diabetes is a disease of metabolic dysregulation. Hyperglycemia and oxidative stress play a role in the development of late diabetic complications. Increased retinal vasopermeability occurs early in diabetes and is crucial for the development of sight-threatening diabetic retinopathy. Serum prolactin is proteolytically processed to vasoinhibins that inhibit the excessive retinal vasopermeability related to diabetic retinopathy. The aim is to study the role of serum prolactin and lipid profile in the pathogenesis of retinopathy in type 2 diabetics and to correlate the changes in serum prolactin levels. Methods: A case control study was done with 90 patients divided into 3 groups (healthy controls, Type 2 Diabetes without retinopathy and Type 2 Diabetes with retinopathy) with inclusion and exclusion criteria. Fasting blood samples were collected and fasting plasma glucose, serum Prolactin were measured. Multiple comparisons between different groups were done using ANOVA test. Results: In the present study decreased serum prolactin levels were observed in patients of Type 2 Diabetes with retinopathy compared to Type 2 Diabetes without retinopathy and controls. Mean ± S.D of Fasting plasma glucose, was highest in Group 3. Mean ± S.D of serum prolactin (7.737 ± 2.63) was low in Group 3. Interpretations & Conclusion: The circulating levels of prolactin were decreased in patients with diabetic retinopathy due to glycosylation and were higher in diabetic patients without retinopathy and healthy controls. Increased prolactin levels influence the progression of retinopathy after its intraocular conversion to vasoinhibins which can reduce the pathological retinal vasopermeability in diabetes and increase in prolactin can be considered to have protective role in pathogenesis of diabetic retinopathy and also may be considered as a treatment option for retinopathy.
Key words: Prolactin; Diabetic retinopathy; Vasoinhibins; Retinal vasopermeability
Advanced logic gates for ultrafast network interchanges
By overcoming speed bottlenecks from electronic switching as well as optical/electronic conversions, allâoptical logic gates can permit further exploitation of the nearly 40 THz of bandwidth available from optical fibers. We focus on the use of optical solitons and allâoptical logic gates to implement ultrafast ââinterchangesââ or switching nodes on packet networks with speeds of 100 Gbit/s or greater. For example, allâoptical logic gates have been demonstrated with speeds up to 200 Gbit/s, and they may be used to decide whether to add or drop a data packet. The overall goal of our effort is to demonstrate the key enabling technologies and their combination for header processing in 100 Gbit/s, timeâdivisionâmultiplexed, packed switched networks. Solitonâbased fiber logic gates are studied with the goal of combining attractive features of solitonâdragging logic gates, nonlinear loop mirrors, and erbiumâdoped fiber amplifiers to design logic gates with optimum switching energy, contrast ratio, and timing sensitivity. First, the experimental and numerical work studies lowâlatency soliton logic gates based on frequency shifts associated with crossâphase modulation. In preliminary experiments, switching in 15 m long lowâbirefringent fibers has been demonstrated with a contrast ratio of 2.73:1. Using dispersionâshifted fiber in the gate should lower the switching energy and improve the contrast ratio. Next, the lowâbirefringent fiber can be crossâspliced and wrapped into a nonlinear optical loop mirror to take advantage of mechanisms from both soliton dragging and loop mirrors. The resulting device can have low switching energy and a timing window that results from a combination of soliton dragging and the loop mirror mechanisms.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87474/2/605_1.pd
Compactness Ratio as an Indicator for the Efficiency of Road Transportation Network in Postmodern Iraqi Cities
The location of the city affects the composition and distribution of land uses, where topography and terrain works to influence the forms taken by cities and regions and the modes of transport used. Thus, the proportion of solidarity greatly affect the roads and streets, which take multiple forms vary depending on the modes of transport used in them. Since the distribution of road networks is efficient and achieves the mobility of thepopulation in the city the more efficient the activities and events distributed in the area of the city, so it was necessary to rely on two main factors, the area and the population in measuring the degree of availability of the road network in the city to evaluate the efficiency of Connected. As the greater the proportion of the compactness of the city, the more concentrated uses of the ground at a higher density and less transportdistance, which is the city of Iraq pre-modernity to give greater efficiency of the transport network and vice versa when the proportion of solidarity to the city scattered uses of the earth less intensity and a greater transport distance, Post-modernity to give less efficiency to the transport network. Therefore, it was necessary to assess the efficiency of the network in the urban area by measuring the proportion of solidarity. Therefore, the index of the ratio of the integration of the transport network as an indicator of the integration of the city through its application to the urban centers of the provinces of Iraq to measure the efficiency of the transport network
SERUM PROLACTIN LEVELS IN TYPE-II DIABETES MELLITUS WITH RETINOPATHY PATIENTS IN AND AROUND HYDERABAD
Background & Objectives: Diabetes is a disease of metabolic dysregulation. Hyperglycemia and oxidative stress play a role in the development of late diabetic complications. Increased retinal vasopermeability occurs early in diabetes and is crucial for the development of sight-threatening diabetic retinopathy. Serum prolactin is proteolytically processed to vasoinhibins that inhibit the excessive retinal vasopermeability related to diabetic retinopathy. The aim is to study the role of serum prolactin and lipid profile in the pathogenesis of retinopathy in type 2 diabetics and to correlate the changes in serum prolactin levels. Methods: A case control study was done with 90 patients divided into 3 groups (healthy controls, Type 2 Diabetes without retinopathy and Type 2 Diabetes with retinopathy) with inclusion and exclusion criteria. Fasting blood samples were collected and fasting plasma glucose, serum Prolactin were measured. Multiple comparisons between different groups were done using ANOVA test. Results: In the present study decreased serum prolactin levels were observed in patients of Type 2 Diabetes with retinopathy compared to Type 2 Diabetes without retinopathy and controls. Mean ± S.D of Fasting plasma glucose, was highest in Group 3. Mean ± S.D of serum prolactin (7.737 ± 2.63) was low in Group 3. Interpretations & Conclusion: The circulating levels of prolactin were decreased in patients with diabetic retinopathy due to glycosylation and were higher in diabetic patients without retinopathy and healthy controls. Increased prolactin levels influence the progression of retinopathy after its intraocular conversion to vasoinhibins which can reduce the pathological retinal vasopermeability in diabetes and increase in prolactin can be considered to have protective role in pathogenesis of diabetic retinopathy and also may be considered as a treatment option for retinopathy.
Key words: Prolactin; Diabetic retinopathy; Vasoinhibins; Retinal vasopermeability
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