47 research outputs found
Effects of Gas Cross-over through the Membrane on Water Management in the Cathode and Anode Sides of PEM Fuel Cell
Water management in a proton exchange membrane fuel cell (PEMFC) is numerically modeled by considering the 2D, non-isothermal steady flow assumptions. Governing equations are solved in all cell layers including cathode and anode electrodes by finite volume method using a single-region approach. The effect of gas cross-over through the membrane is studied on cell performance. This consideration, not only improves the general accuracy of modeling but also makes it possible to model energy losses due to direct reaction of reactant gases. The effect of some key variables such as liquid water diffusivity, current density, membrane thickness, etc. on PEMFC conditions such as the amount of saturated liquid water, power density, cell temperature, cross-over efficiency and so on are examined. It was observed that the amount of saturated liquid water on the anode side is considerably important. This observation addresses needs for further investigation of liquid water behavior in the anode electrode. The amount of liquid water saturation in both the cathode and anode electrodes is increased with increasing the current density. The results showed that at the current density of 0.2 A/cm2, cross-over effect causes about 10% reduction in cell efficiency and by decreasing the current density this effect is enhanced
Safety and discontinuation rate of dimethyl fumarate (Zadiva®) in patients with multiple sclerosis: an observational retrospective study
BACKGROUND: This study evaluates the real-world safety and discontinuation rate of Zadiva® (generic product of dimethyl fumarate (DMF)) in Iranian patients with relapsing-remitting multiple sclerosis (RRMS), supplementing existing clinical evidence from randomized controlled trials. METHODS: This retrospective observational study evaluated the real-world safety and discontinuation rate of DMF in RRMS patients from Amir A'lam referral hospital's neurology clinic. Data on safety, discontinuation rate, and clinical disease activity were collected retrospectively. The study aimed to assess the discontinuation rate, safety, and reasons for discontinuation, as well as the number of patients experiencing a relapse, MRI activity, and EDSS scores. RESULTS: In total, 142 RRMS patients receiving DMF were included in the study, with 15 discontinuing treatment due to adverse events, lack of efficacy, or pregnancy. Notably, a significant reduction in relapse rates was observed, with 90.8% of patients remaining relapse-free throughout the study period. After 1 year of treatment with Zadiva®, only 17.6% of patients experienced MRI activity, whereas the EDSS score remained stable. CONCLUSIONS: This study provides important real-world data on the safety and tolerability of Zadiva® in RRMS patients. The results indicate that Zadiva® is generally well tolerated and safe, with a low discontinuation rate due to adverse events or lack of efficacy. These findings suggest that Zadiva® is an effective and safe treatment option for RRMS patients in real-world practice
Safety and Efficacy of MLC601 in Iranian Patients after Stroke: A Double-Blind, Placebo-Controlled Clinical Trial
Objective. To investigate the safety and efficacy of MLC601 (NeuroAid) as a traditional Chinese medicine on motor recovery after ischemic stroke. Methods. This study was a double-blind, placebo-controlled clinical trial on 150 patients with a recent (less than 3 month) ischemic stroke. All patients were given either MLC601 (100 patients) or placebo (50 patients), 4 capsules 3 times a day, as an add-on to standard stroke treatment for 3 months. Results. Sex, age, elapsed time from stroke onset, and risk factors in the treatment group were not significantly different from placebo group at baseline (P > .05). Repeated measures analysis showed that Fugl-Meyer assessment was significantly higher in the treatment group during 12 weeks after stroke (P < .001). Good tolerability to treatment was shown, and adverse events were mild and transient. Conclusion. MLC601 showed better motor recovery than placebo and was safe on top of standard ischemic stroke medications especially in the severe and moderate cases
Energy-Efficient Service-Oriented Architecture for Mobile Cloud Handover
Mobile cloud computing uses features to deliver outsourcing data to remotely available mobile devices. However, the flexible nature of the mobile device is a critical challenge for the mobile cloud computing environment. The mobile phone significantly degrades the data transfer performance when initiating the handover process. Thus, an energy-efficient handover process could improve the quality of service (QoS). Here, we introduce a secure energy-efficient and quality-of-service architecture (EEQoSA) for the handover process in the mobile cloud computing environment. The proposed architecture involves four layers: application, the Internet protocol multimedia subsystem (IPMS), communication, and media with connectivity layers. These four layers collectively handle the energy-efficiency, security and QoS parameters. Existing service-oriented architectures designed for mobile cloud computing are based on the symmetric encryption cryptography to support different media services. However, this approach easily allows an adversary to expose the symmetric key and gain access to private data. Thus, our proposed architecture uses the secure and strong authentication (SSA) process at the IPMS layer by protecting the media services from unauthorized users, as the IPMS is the central layer that could be the entry point for an adversary. Furthermore, to extend the mobile lifetime during the handover process, an energy detection (ED) model is deployed at the communication layer to detect the energy level of the mobile device prior to the handover initialization process. The media with the connectivity layer supports the secure handover process using a priority enforcement module that allows only legitimate users to complete the re-registration process after initiating the handover. Finally, the architecture is tested using the CloudSim simulation environment and validated by a comparison with other known service-oriented architectures.https://doi.org/10.1186/s13677-017-0079-
Towards Efficient and Scalable Data-Intensive Content Delivery: State-of-the-Art, Issues and Challenges
This chapter presents the authors’ work for the Case Study entitled “Delivering Social Media with Scalability” within the framework of High-Performance Modelling and Simulation for Big Data Applications (cHiPSet) COST Action 1406. We identify some core research areas and give an outline of the publications we came up within the framework of the aforementioned action. The ease of user content generation within social media platforms, e.g. check-in information, multimedia data, etc., along with the proliferation of Global Positioning System (GPS)-enabled, always-connected capture devices lead to data streams of unprecedented amount and a radical change in information sharing. Social data streams raise a variety of practical challenges: derivation of real-time meaningful insights from effectively gathered social information, a paradigm shift for content distribution with the leverage of contextual data associated with user preferences, geographical characteristics and devices in general, etc. In this article we present the methodology we followed, the results of our work and the outline of a comprehensive survey, that depicts the state-of-the-art situation and organizes challenges concerning social media streams and the infrastructure of the data centers supporting the efficient access to data streams in terms of content distribution, data diffusion, data replication, energy efficiency and network infrastructure. The challenges of enabling better provisioning of social media data have been identified and they were based on the context of users accessing these resources. The existing literature has been systematized and the main research points and industrial efforts in the area were identified and analyzed. In our works, in the framework of the Action, we came up with potential solutions addressing the problems of the area and described how these fit in the general ecosystem
The effects of polarity of click stimulation on auditory brainstem responses (ABR) in patients with cochlear and retro-cochlear disorders in Amiralam and Resalat Hospitals 1995-97
Background: Auditory brainstem response (A.B.R) is one of the most important electrophysiological tests in evaluating of auditory system, especially for diagnosing of auditory nerve and brainstem disorders. It is a non-invasive test and has reliability and validity characteristic. There is no contra-indication for this test. One of the most important of stimulation parameters of A.B.R is click polarity (rarefaction, condensation and alternative). Some of the investigators believed that different polarities have no effects on A.B.R are affected by different polarities. Materials and Methods: In this study, the results of ABR of 148 patients (296 ears) were compared with three different polarities of rarefaction, condensation and alternative half click stimuli. The cases were categorized in three groups of normal (60 cases), cochlear (62 cases) and retro-cochlear (17 cases). This classification were done according to the hearing level in pure tone audiometry results in three frequencies of 1000, 2000, 4000 Hz and to the site of the their disorders. The mean absolute latencies of waves I, III and V were obtained for each polarity. Inter-peak latency (I.P.L) of wave also measured in three groups (normal, cochlear and retro-cochlear). Results: The results were showed a significant difference between absolute latency of wave I among different polarities on three above mentioned groups (P0.05). Conclusion: It was concluded that rarefaction polarity has better and more stable results of ABR tests
A Study On The Results Of Competing Sentence Test In Patients With Cerebrovascucular Accident
Background: Cerebrovasular diseases (CVD) are one of the most common anomalies which may affect on auditory cortex. In this research we have tried to evaluate the function of CANS in a group of 50-70 years old cerebrovascular accident (CVA) patients without hearing problem by using Persian version of C.S.T. Materials and Methods: This cross-sectional analytic study was established at Loghman-e-Hakim Hospital on a group of 30 normal subject (15 male, 14 female) and a group of 40 patients with CVA including 30 patients (16 male, 14 female) with abnormal CT scan and 10 patients with normal CT scan. Results: Routine audiologic test including: Pure tone audiometry, Immitance audiometry and speech audiometry were nearly normal in all cases. There were significant differences between mean scores of CST in the patients with CVA and control group (P 0.05). In spite of nearly normal hearing and high scores in the simple speech tests such as SDS, there were significant differences in mean scores of CST in both ears of CVA patients (P< 0.05). Another important point is that in some of patients with CVA. Conclusion: Although common radiologic evaluations such as CT scan showed no anatomic or structural anomaly but central auditory assessments such as CST can show dysfunctions of CANS. Therefore, CST might be a valuable test in CANS batteries for the cerebrovascular diseases
EFFECTS OF 6-MONTHS TREATMENT WITH DONEPEZIL AND RIVASTIGMIN ON RESULTS OF NEUROPSYCHOLOGICAL TESTS OF MMSE, NPI, CLOCK AND BENDER IN PATIENTS WITH ALZHEIMER'S DISEASE
Alzheimer's disease is the most common degenerative disease of brain. Nowadays, the most common treatment being used to slow down disease progression, include Donepezil , Rivastigmine and Galantamine, which all of them act as inhibitors of acetyl cholinesterase. General purpose of our study was to show effects of treatment with Donepezil and Rivastigmine, as two drugs that commonly used for treatment of AD in Iran and to compare these effects between two drugs. Samples selected from patients who had Alzheimer` disease with DSM IV criteria and were candidate of receiving Donepezil or Rivastigmine, as treatment of AD, for the first time. We used four neuropsychological tests including MMSE, NPI, Clock and Bender to assess patient's cognitive and behavioral changes during treatment with two drugs. Patients divided to two groups (each group 35 cases); Patients with plan of taking Donepezil entered into one of the groups and patients with plan of taking Rivastigmine entered into another. The four tests were completed once before starting treatment and then, 1 month, 3 months and 6 months after treatment with Donepezil and Rivastigmine. MMSE, 6 months after treatment with Donepezil, improved from 20.63 before treatment to 21.83, which is statistically significant (P = 0.04). Also, MMSE, 6 months after treatment with Rivastigmine, improved from 20.03 before treatment to 22.71, which was statistically significant (P = 0.007). About Clock test, there was a significant improvement from 5.74 before treatment to 6.4 after 6 months of treatment with Rivastigmine; while this significant improvement was not seen in patients receiving Donepezil. In two other tests, no significant differences were seen before and after treatment. Also, No significant difference was detected between two groups and so no different effects on these tests between Donepezil and Rivastigmine in 6 months period of treatment
"THE EFFECTS OF ANODAL IONTOPHORESIS OF EPINEPHRINE ON NEUROMUSCULAR RESPONSES IN HEALTHY MEN AND PATIENTS WITH MYASTHENIA GRAVIS "
Iontophoresis of epinephrine for assessment of neuromuscular junction response is a new technique that can improve diagnose of neuromuscular dysfunction. The purpose of this study was to investigate the effects of iontophoresis of epinephrine on neuromuscular junction response. Iontophoresis of epinephrine solution (1mg/ml), sodium chloride, calcium gluconate, epinephrine with sodium chloride and distilled water was applied in five groups of healthy men and 7 patients with myasthenia gravis (MG). Amplitude, depolarization, repolarization and recovery times and slops of compound muscle action potential (CMAP) were measured. Also low repetition stimulus tests were applied before and after iontophoresis of epinephrine. Following results were obtained: 1) iontophoresis of sodium ion increased depolarization time, and iontophoresis of sodium and calcium ions increased recovery and duration times of CMAP, 2) slope of depolarization and recovery were reduced by iontophoresis of active ions, 3) iontophoresis of epinephrine increased slope of recovery or Na-K transport at 10 and 15 minutes after iontophoresis, 4) iontophoresis of epinephrine in patients with MG reduced amplitudes of all CMAPs and percentage of decrement between first and fifth signal increased at low frequency stimulus test, and 5) iontophoresis of epinephrine in normal group increased percentage of amplitude increment between first and fifth signal in low frequency stimulation test. Neuromuscular responses in patients with MG in comparison to normal men are sensitive to iontophoresis of epinephrine and demonstrate significant decrement findings to low repetition stimulus tests. Iontophoresis of epinephrine with RNS tests can be useful in assessments of these patients