365 research outputs found
Novel Polymeric Prodrugs of Valproic Acid as Anti- Epilepsy Drugs: Synthesis, Characterization and In-vitro Evaluation
Purpose: To synthesize and evaluate, in-vitro, novel polymeric prodrugs of valproic acid (VPA) for antiepileptic activity.Methods: Homopolymer of 4-chloromethyl styrene (CMS) and its copolymers with various acrylic-type monomers such as 2-hydroxyethyl methacrylate and methyl methacrylate were prepared by free radical polymerization method. VPA was then covalently linked to the obtained polymers by treating CMS polymers with sodium valproate. All the compounds were characterized by Fourier transform infrared (FT-IR), nuclear magnetic resonance (1H and 13C-NMR), elemental analyses, and gel permeation chromatography (GPC). The release of VPA from polymeric prodrugs was studied using cellophane membrane dialysis bags containing aqueous buffer solutions (pH 1, 7 and 10) at 37 oC. The quantity of released drug was detected by ultraviolet (UV) spectroscopy.Results: 1H-NMR and elemental analyses data for calculating mole composition of CMS polymers were relatively in good agreement. FT-IR and NMR data for the polymeric prodrugs showed attachment of drug substituents to phenyl rings of CMS units via methylene spacer. The drug-release profiles indicated that selective hydrolysis of ester bond between the drug and the polymer backbone is strongly dependent on polymer hydrophilicity and the pH of the hydrolysis solution.Conclusion: The synthesized VPA polymeric prodrugs may be cost-effective compounds for release of VPA in vivo when formulated as controlled release systems.Keywords: 4-Chloromethyl Styrene, Valproic Acid, Polymeric Prodrugs, Controlled Release, Hydrolysi
Study of electro-absorption effects in 1300nm In(Ga)As/GaAs quantum dot materials
No abstract available
GaAs-based Self-Aligned Stripe Superluminescent Diodes Processed Normal to the Cleaved Facet
We demonstrate GaAs-based superluminescent diodes (SLDs) incorporating a window-like back facet in a self-aligned stripe. SLDs are realised with low spectral modulation depth (SMD) at high power spectral density, without application of anti-reflection coatings. Such application of a window-like facet reduces effective facet reflectivity in a broadband manner. We demonstrate 30mW output power in a narrow bandwidth with only 5% SMD, outline the design criteria for high power and low SMD, and describe the deviation from a linear dependence of SMD on output power as a result of Joule heating in SLDs under continuous wave current injection. Furthermore, SLDs processed normal to the facet demonstrate output powers as high as 20mW, offering improvements in beam quality, ease of packaging and use of real estate. © (2016) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only
Assessing iranian adolescent girls' needs for sexual and reproductive health information
Purpose To explore the views and experiences of adolescent girls and key adults regarding the necessity of providing sexual and reproductive health (SRH) information and services for adolescent girls in Iran. Methods This was a qualitative study; the data were coded and categorized in content analysis by MAXQDA10 and were gathered through focus groups with adolescent girls and their mothers and semi-structured interviews with school counselors, sociologists, health providers, state and nongovernmental directors of health programs, clergy, and health policy makers in the Iranian cities of Mashhad, Tehran, Shahroud, and Qom. Results There were six main reasons for the need to provide SRH services for adolescent girls: a lack of adequate knowledge about SRH, easy access to inaccurate information sources, cultural and social changes, increasing risky sexual behaviors among adolescents, religion's emphasis on sex training of children and adolescents, and the existence of cultural taboos. Conclusions Most participants confirmed the necessity of providing SRH services for adolescent girls, so instead of talking about provision or non-provision of these services, it is important for policy makers to plan and provide SRH services that can be consistent with cultural and religious values for adolescent girls. © 2014 Society for Adolescent Health and Medicine. All rights reserved
Isolation of rapid growing mycobacteria from soil and water in Iran
A total of 350 soil samples were collected from different part of Uremia city and suburbs. We used 3% sodium lauryl sulfate and 1% NaOH for decontamination of soil samples. Of 350 samples, mycobacteria were isolated from 65 (18.3%) specimens. Mycobacterium fortuitum with 18(5.14) strains yielded the highest frequency of isolation. The other isolates were: Mycobacterium peregrinum 11(3.14%), Mycobacterium flvescens 10 (2.85%), Mycobacterium chelonae 6 (1.71%), Mycobacterium mucogenicum 6(1.71%), Mycobacterium thermoresistable 4(1.14%), Mycobacterium abscessus 3 (0.85%), Mycobacterium neoaurum 2(0.57%), Mycobacterium smegmatis 2 (0.57%) and M. fortuitum third biovalant complex 3 (0.85%). The mean pH of soil was 7.89 ± 0.379 (max 8.5, min 7.5). Our data showed an abundant occurrence of mycobacteria in low pH (P value = 0001). We also collected 120 water samples from rivers, brooks and drinking water. Water samples decontaminated were by adding cetylpyridinium chloride (CPC) to give final concentration of 0.05%. Mycobacteria isolated from 12 water samples. The predominant isolated species were M. fortuitum and Mycobacterium cheloni. The majorityisolates were from brooks and surface waters
Numerical modelling for nanoparticle thermal migration with effects of shape of particles and magnetic field inside a porous enclosure
Computational modelling for nanoparticle migration inside a permeable space has been reported. Impacts of shape factor and radiation were included in the mathematical model. CVFEM was employed to analyse magnetic force impact. Impacts of magnetic radiative parameters, buoyancy forces and nanoparticle shape on nanomaterial behaviour were demonstrated. Utilizing the Darcy model helps us to predict the behaviour of porous media. Outputs revealed higher convective mode can be achieved with augmenting buoyancy force while opposite outcome appears when magnetic field is imposed. Thermal plume vanishes with the rise of conductive mode which is gained as Hartmann increases
Higher-order approximation of cubic–quintic duffing model
We apply an Artificial Parameter Lindstedt-Poincaré Method (APL-PM) to find improved approximate solutions for strongly nonlinear Duffing oscillators with cubic–quintic nonlinear restoring force. This approach yields simple linear algebraic equations instead of nonlinear algebraic equations without analytical solution which makes it a unique solution. It is demonstrated that this method works very well for the whole range of parameters in the case of the cubic-quintic oscillator, and excellent agreement of the approximate frequencies with the exact one has been observed and discussed. Moreover, it is not limited to the small parameter such as in the classical perturbation method. Interestingly, This study revealed that the relative error percentage in the second-order approximate analytical period is less than 0.042% for the whole parameter values. In addition, we compared this analytical solution with the Newton– Harmonic Balancing Approach. Results indicate that this technique is very effective and convenient for solving conservative truly nonlinear oscillatory systems. Utter simplicity of the solution procedure confirms that this method can be easily extended to other kinds of nonlinear evolution equations
Influence of upstream strut on hydrogen fuel distribution inside the supersonic combustion chamber
© 2020 Hydrogen Energy Publications LLC The efficient fuel mixing in the combustion tank enhances the overall performance of scramjet. Current attempt examines the existence of the strut on the fuel mixing of the multi hydrogen jets at supersonic flow. The numerical approach was employed to visualize the 3D flow behind the strut with multi fuel-jets. The free-stream Mach is 2.2, and four multi jets released hydrogen inside the combustor with the sonic condition. The impact of jet arrangements and the total pressure ratio on the mixing effect of the strut is fully described. Our results indicate that fuel mixing and penetration improved due to the formation of the large subsonic region behind the strut. According to achieved results, the increasing jet space from 1Dj to 5Dj raises the overall mixing to 15% in our proposed model
Clinical presentation of coronary arteriovenous fistula according to age and anatomic orientation
Background: Coronary arteriovenous fistulas (CAVFs) are direct connections from one or more coronary arteries to cardiac chambers or a large vessel. They are mostly of congenital origin. The aim of this study was to describe clinical presentation and also delineate the course and management of CAVF. Methods: Clinical data, chest x-rays, echocardiographic and angiographic evaluation of 40 patients with congenital CAVF during 1990 to 2008 were reviewed retrospectively. Results: Seventeen patients were �20 years old (42.5) were mostly asymptomatic, and twenty tree cases were older than 20 years old (57.5), mostly symptomatic (P < 0.05). Twenty one (52.5) patients had pure CAVF and nineteen (47.5) patients with associated intarcardiac congenital heart disease (15) or acquired valvular and coronary arteries diseases (32.5). CAVFs mostly originated from left anterior descending artery (LAD) (42.5) and mostly drained into the main pulmonary artery (MPA) (35 ). Twenty-four patients underwent CAVF surgical ligation. From twenty-one patients with pure CAVF, eight (38) patients were complicated by congestive heart failure and aneurism formation of fistula. Conclusion: Unlike some previous reports, in our study, the most prevalent origin site for CAVFs was the left anterior descending (LAD). Most patients with CAVFs especially those who went first diagnosed before 20 years old were asymptomatic. On the other hand, as the continuous murmur is not always detected in children or infants, consequently, cases of spontaneous closure may remain undetected. All symptomatic and asymptomatic patients with moderate to severe shunting should be operated on and minimal morbidity and good surgical results could be expected
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