470 research outputs found
Effect of acute caffeine administration on PTZ-induced seizure threshold in mice: Involvement of adenosine receptors and NO-cGMP signaling pathway
Abstract
Purpose:
Caffeine is a non-selective antagonist of A1 and A2A adenosine receptors (ARs). In this regard, nitric oxide (NO) is partly involved in the central effects of caffeine. In this study, we examined the effect of acute caffeine administration on pentylenetetrazole (PTZ)-induced seizure threshold by focusing on A1Rs, A2ARs, and NO-cGMP signaling pathway.
Methods:
NMRI male mice (25–30 g) received caffeine (5, 50, and 100 mg/kg) alone, whereas 8-CPT (1 and 5 mg/kg, a selective A1Rs antagonist), SCH-442416 (5 and 10 mg/kg, a selective A2ARs antagonist) or sildenafil (5 and 10 mg/kg, a phosphodiesterase 5 inhibitor) were administrated alone or as pre-treatment before caffeine. Seizure threshold was assessed by intravenous infusion of PTZ. Nitric oxide metabolites (NOx) were measured with the Griess method.
Results:
When administrated alone, caffeine (5 and 50 mg/kg) and 8-CPT (1 and 5 mg/kg) significantly decreased seizure threshold, while 100 mg/kg of caffeine, SCH-442416 or sildenafil did not change it. Only pre-treatment with SCH-442416 (5 and 10 mg/kg) or sildenafil (5 and 10 mg/kg) before 100 mg/kg of caffeine significantly decreased seizure threshold. Moreover, NOx levels significantly decreased following alone administration of caffeine (100 mg/kg) or 8-CPT (5 mg/kg).
Conclusion:
The results of present study showed that 5 and 50 mg/kg of caffeine had a proconvulsant effect but caffeine at a dose of 100 mg/kg had no effect on seizure threshold. In addition, it seems that the effect caffeine on seizure threshold is partly mediated through ARs or modulation of the NO-cGMP signaling pathway.
Keywords: Seizure Caffeine Nitric oxide Adenosine receptors
Pentylenetetrazol
Dynamic Windows Scheduling with Reallocation
We consider the Windows Scheduling problem. The problem is a restricted
version of Unit-Fractions Bin Packing, and it is also called Inventory
Replenishment in the context of Supply Chain. In brief, the problem is to
schedule the use of communication channels to clients. Each client ci is
characterized by an active cycle and a window wi. During the period of time
that any given client ci is active, there must be at least one transmission
from ci scheduled in any wi consecutive time slots, but at most one
transmission can be carried out in each channel per time slot. The goal is to
minimize the number of channels used. We extend previous online models, where
decisions are permanent, assuming that clients may be reallocated at some cost.
We assume that such cost is a constant amount paid per reallocation. That is,
we aim to minimize also the number of reallocations. We present three online
reallocation algorithms for Windows Scheduling. We evaluate experimentally
these protocols showing that, in practice, all three achieve constant amortized
reallocations with close to optimal channel usage. Our simulations also expose
interesting trade-offs between reallocations and channel usage. We introduce a
new objective function for WS with reallocations, that can be also applied to
models where reallocations are not possible. We analyze this metric for one of
the algorithms which, to the best of our knowledge, is the first online WS
protocol with theoretical guarantees that applies to scenarios where clients
may leave and the analysis is against current load rather than peak load. Using
previous results, we also observe bounds on channel usage for one of the
algorithms.Comment: 6 figure
Evaluation of SIP Signalling and QoS for VoIP over OLSR MANET Routing Protocol
Abstract:
This paper evaluates the SIP based VoIP applications over the Optimized Link State Routing protocol (OLSR) as a proactive routing protocol for Mobile Ad Hoc Networks (MANET) using Static, Uniform, and Random mobility models. The evaluation considered PCM, LQS, IPTelephony, and GSM voice codecs to study the SIP signaling performance and the voice Quality of Service (QoS) for VoIP calls over OLSR MANET. The simulation efforts performed in OPNET Modeler 17.1. The results show that VoIP over OLSR MANET has good performance over Static and Uniform mobility models while it has variable performance with Random models. SIP signaling has large delays compared with the voice signaling which reduce the VoIP performance and increases the call's duration. In addition, GSM and LQS based VoIP calls have an acceptable level of QoS while PCM and IP-Telephony based VoIP calls have a low level of QoS over different types of mobility models. Furthermore, the location and the mobility of SIP server affect the number of hops and the SIP signaling performance between the different parties of the VoIP call
Self-sustained oscillations in whiskers without vortex shedding
Sensing the flow of water or air disturbance is critical for the survival of
many animals: flow information helps them localize food, mates, and prey and to
escape predators. Across species, many flow sensors take the form of long,
flexible cantilevers. These cantilevers are known to exhibit sustained
oscillations when interacting with fluid flow. In the presence of vortex
shedding, the oscillations occur through mechanisms such as wake- or
vortex-induced vibrations. There is, however, no clear explanation for the
mechanisms governing the sustained oscillation of flexible cantilevers without
vortex shedding. In recent work, we showed that a flexible cylindrical
cantilever could experience sustained oscillations in its first natural
vibration mode in water at Reynolds numbers below the critical Reynolds number
of vortex shedding. The oscillations were shown to be driven by a frequency
match (synchronization) between the flow frequency and the cantilever's
first-mode natural frequency. Here, we use a body-fitted fluid-structure solver
based on the Navier-Stokes and nonlinear structural equations to simulate the
dynamics of a cantilevered whisker in the air at a subcritical value of
Reynolds number. Results show that second-mode synchronization governs the
whisker's sustained oscillation. Wavy patterns in the shear layer dominate the
whisker's wake during the vibrations, indicating that parallel shear layers
synchronize with the whisker's motion. As a result of this synchronization,
oval-shaped motion trajectories, with matching streamwise and cross-flow
vibration frequencies, are observed along the whisker. The outcomes of this
study suggest possible directions for designing artificial bio-inspired flow
sensors
Smoking Knowledge, Attitude and Behavior of Child Labor Who Live in Tehran during 2013-2014
Background: Children and adolescent smoking is one of the most important health problems in the world. There is a major concern that child labor may generate a pseudo maturity syndrome, including smoking.The current survey focus on smoking behavior, knowledge and attitude of child labor are working in Tehran.Materials and Methods: The study adopted a cross-sectional design, based on a primary pilot descriptive cross sectional study, using GYTS self-administered questionnaire. 816 child labor, which were student of work labor schools or worked as child labor on Tehran parks and crossing roads, were randomly selected using multi stage cluster sampling. DATA analyzed using SPSS v.22 (IBM statistic) software and chi square test to compare the frequency of variables in different groups.Results: 50.6% of our participants were boy and child laboring age varied from 11 to 17 years old. 18.6% of child labor had smoking experience (Confident Interval 95%=17.3-20.1). 9.8% of them were current smoker (CI 95%=8.6-10.9) and 1.2% were current regular smoker (CI 95%=0.9-2.1). Child labor smoking hazard knowledge was evaluated by considering the minimum and maximum score of 10 to 30. Results demonstrated that the mean score of knowledge, attitude and behavior were 17.1±6.2, 36.5±16.1 (range 15-45) and 46.1±3.0 (range 25-75), respectively.Conclusion: Considering to our findings, planning tobacco control program for these specific groups is required, aiming at preventing cigarette smoking by increasing the knowledge and correcting their attitude
Chebyshev cardinal functions for solving volterra-fredholm integro- differential equations using operational matrices
Abstract In this paper, an effective direct method to determine the numerical solution of linear and nonlinear Fredholm and Volterra integral and integro-differential equations is proposed. The method is based on expanding the required approximate solution as the elements of Chebyshev cardinal functions. The operational matrices for the integration and product of the Chebyshev cardinal functions are described in detail. These matrices play the important role of reducing an integral equation to a system of algebraic equations. Illustrative examples are shown, which confirms the validity and applicability of the presented technique
The effects of coenzyme Q10 supplementation on lipid profiles among patients with coronary artery disease: A systematic review and meta-analysis of randomized controlled trials
Background
Chronic inflammation and increased oxidative stress significantly contribute in developing coronary artery disease (CAD). Hence, antioxidant supplementation might be an appropriate approach to decrease the incidence of CAD. This systematic review and meta-analysis was aimed to determine the effects of coenzyme Q10 (CoQ10) supplementation on lipid profile, as one of the major triggers for CAD, among patients diagnosed with coronary artery disease.
Methods
EMBASE, Scopus, PubMed, Cochrane Library, and Web of Science were searched for studies prior to May 20th, 2018. Cochrane Collaboration risk of bias tool was applied to assess the methodological quality of included trials. I-square and Q-tests were used to measure the existing heterogeneity across included studies. Considering heterogeneity among studies, fixed- or random-effect models were applied to pool standardized mean differences (SMD) as overall effect size.
Results
A total of eight trials (267 participants in the intervention group and 259 in placebo group) were included in the current meta-analysis. The findings showed that taking CoQ10 by patients with CAD significantly decreased total-cholesterol (SMD -1.07; 95% CI, − 1.94, − 0.21, P = 0.01) and increased HDL-cholesterol levels (SMD 1.30; 95% CI, 0.20, 2.41, P = 0.02). We found no significant effects of CoQ10 supplementation on LDL-cholesterol (SMD -0.37; 95% CI, − 0.87, 0.13, P = 0.14), lipoprotein (a) [Lp(a)] levels (SMD -1.12; 95% CI, − 2.84, 0.61, P = 0.20) and triglycerides levels (SMD 0.01; 95% CI, − 0.22, 0.24, P = 0.94).
Conclusions
This meta-analysis demonstrated the promising effects of CoQ10 supplementation on lowering lipid levels among patients with CAD, though it did not affect triglycerides, LDL-cholesterol and Lp(a) levels.
Keywords:
Coenzyme Q10
Lipid profiles
Coronary artery disease
Meta-analysi
The effects of quercetin supplementation on lipid profiles and inflammatory markers among patients with metabolic syndrome and related disorders: A systematic review and meta-analysis of randomized controlled trials
Aims: This systematic review and meta-analysis of randomized controlled trials (RCTs) was performed to determine the effect of quercetin administration on lipid profiles and inflammatory markers among patients with metabolic syndrome (MetS) and related disorders. Methods: We searched systematically online databases including Cochrane Library, EMBASE, MEDLINE, and Web of Science to identify the relevant RCTs until November 2018. Q-test and I2 statistics were applied to assess heterogeneity among included studies. Data were combined using fixed- or random-effects model and presented as standardized mean difference (SMD) with 95 confidence interval (CI). Results: Out of 591 citations, 16 RCTs were included in the meta-analysis. The pooled findings showed that quercetin consumption significantly decreased total-cholesterol (SMD = �0.98; 95 CI, �1.48, �0.49; p < 0.001; I2: 94.0), LDL-cholesterol (SMD = �0.88; 95 CI, �1.35, �0.41; p < 0.001; I2: 92.7) and C-reactive protein (CRP) levels (�0.64; 95 CI, �1.03, �0.25; p = 0.001; I2: 90.2). While, quercetin supplementation did not significantly affect triglycerides (TG) (SMD = �0.32; 95 CI, �0.68, 0.04; p = 0.08; I2: 84.8), HDL-cholesterol (SMD = 0.20; 95 CI, �0.20, 0.24; p = 0.84; I2: 70.6), interleukin 6 (IL-6) (SMD = �0.69; 95 CI, �1.69, 0.31; p = 0.17; I2: 94.5) and tumor necrosis factor-alpha (TNF-α) levels (SMD = �0.06; 95 CI, �0.25, 0.14; p = 0.58; I2: 35.6) Conclusions: In summary, the current meta-analysis demonstrated that quercetin supplementation significantly reduced total-cholesterol, LDL-cholesterol, and CRP levels, yet did not affect triglycerides, HDL-cholesterol, IL-6 and TNF-α among patients with MetS and related disorders. © 2019, © 2019 Taylor & Francis Group, LLC
Regulation of ctla-4 and pd-l1 expression in relapsing-remitting multiple sclerosis patients after treatment with fingolimod, ifnβ-1α, glatiramer acetate, and dimethyl fumarate drugs
Multiple sclerosis (MS) is a chronic demyelinating disease of the central nervous system (CNS) that is characterized by inflammation which typically results in significant impairment in most patients. Immune checkpoints act as co-stimulatory and co-inhibitory molecules and play a fundamental role in keeping the equilibrium of the immune system. Cytotoxic T-lymphocyte antigen-4 (CTLA-4) and Programmed death-ligand 1 (PD-L1), as inhibitory immune checkpoints, participate in terminating the development of numerous autoimmune diseases, including MS. We assessed the CTLA-4 and PD-L1 gene expression in the different cell types of peripheral blood mononuclear cells of MS patients using single-cell RNA-seq data. Additionally, this study outlines how CTLA-4 and PD-L1 expression was altered in the PBMC samples of relapsing-remitting multiple sclerosis (RRMS) patients compared to the healthy group. Finally, it investigates the impact of various MS-related treatments in the CTLA-4 and PD-L1 expression to restrain autoreactive T cells and stop the development of MS autoimmunity
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