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51.
52.
Saeed Noee Nasim Salimraftar Majid Abdouss Gholamhossein Riazi 《Polymer International》2013,62(12):1711-1716
To achieve suitable properties for specific applications, we synthesized diclofenac sodium (Ds) imprinted polymer beads with controllable size in the range of around 145 nm to 3 µm in diameter by the precipitation polymerization method using methacrylic acid as functional monomer, trimethylolpropane trimethacrylate as crosslinker and azobisisobutyronitrile as initiator. We analyzed the effect of the porogenic solvent on the morphology and recognition of particles. SEM analysis showed some dissimilarity in appearance of the imprinted polymers. The specific surface areas were 246 m2 g–1 and 260 m2 g–1 for imprinted polymers prepared in a mixture of tetrahydrofuran/acetonitrile (MIP1) and tetrahydrofuran/toluene (MIP2) respectively, which were in good agreement with the binding capacities of 150.4 mg g–1 for MIP1 and 280.4 mg g–1 for MIP2, but the imprinted nanoparticles with a specific selectivity factor of 1.5 had a better recognition property to Ds than the analog template meclofenamate sodium monohydrate (Ms) and also faster rebinding kinetics or greater accessibility of Ds. Finally the imprinted microspheres were successfully applied as a solid phase extraction sorbent for the extraction of Ds from human urine with limits of detection and quantification of 0.085 mg L–1 and 0.227 mg L–1, respectively. © 2013 Society of Chemical Industry 相似文献
53.
In vitro evaluation of biopolymer networks based on crosslinked cellulose with various diamines 下载免费PDF全文
In this study, we investigated some hydrogels based on natural, biodegradable, and biocompatible polysaccharides and cellulose, as sustained release carriers and evaluated their controlled drug release. The crosslinking of bromoacetylated cellulose with various aliphatic and aromatic diamines, such as ethylene diamine, hexamethylene diamine, and paraphenylene diamine, were carried out in N,N‐dimethylformamide in the presence of triethylamine as a base. On the other hand, the synthesized hydrogels were characterized with Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, and CHN elemental analysis. Also, the equilibrium swelling behavior of the hydrogels in water was calculated, and this indicated their sustained expansion. The loading of ceftizoxime antibiotic was carried out on the prepared hydrogels, and the in vitro and drug‐release behaviors were investigated in three different media (HCl solution at pH 3 and bicarbonate buffer solutions at pH 6 and 8). Finally, the release profiles of ceftizoxime from the hydrogels and their loading capacities were determined by ultraviolet–visible absorption measurements at λmax 295 nm. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42568. 相似文献
54.
Nasim Bagvand Shahram Sharifnia Elham Karamian 《Korean Journal of Chemical Engineering》2018,35(8):1735-1740
Given the changes in environmental conditions in the world, photocatalytic conversion of greenhouse gases is of great interest today. Our aim was to increase the photocatalytic efficiency of BiFeO3/ZnS (p-n heterojunction photocatalyst) by varying the molar ratio of ZnS to perovskite structure of BiFeO3 using hydrothermal synthesis. The results of X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), FT-IR spectroscopy showed the small crystal size and suitable distribution of ZnS particles on the BiFeO3 structure. The results of UV-visible, and photoluminescence (PL) spectroscopy analyses showed the good behavior of p-n heterostructure in absorption of visible light and lowering electron-hole recombination. The best visible light photocatalytic efficiency of CO2 reduction, 24.8%, was obtained by an equimolar ratio of BiFeO3/ZnS. 相似文献
55.
Razieh Mohebat Afshin Yazdani-Elah-Abadi Nasim Simin 《Polycyclic Aromatic Compounds》2018,38(2):180-188
1,4-Diazabicyclo[2.2.2]octane (DABCO) has been used as an efficient and reusable solid base catalyst for the rapid and green synthesis of pyran annulated heterocyclic ring systems by the condensation reaction of various activated CH-acids and tetracyanoethylene under conventional heating and microwave irradiation in solvent-free conditions. Excellent yield, very short reaction time (2–5 min), operatinal simplity, easy work-up procedure, avoidance of hazardous or toxic catalysts, and organic solvents are the main advantages of this green methodology which makes it more economic than the other conventional methods. 相似文献
56.
Nasim K. Shattarat Michael D. Symans David I. McLean William F. Cofer 《Engineering Structures》2008,30(5):1335-1345
The response of bridges when subjected to seismic excitation can be evaluated by a number of analysis methods. The traditional approach is to employ linear static or dynamic analyses coupled with appropriate modifiers to account for inelastic response while current design practice is moving towards an increased emphasis on nonlinear static analysis methods. In this study, a preliminary seismic response analysis of a two-span highway bridge was performed using linear dynamic analysis procedures to identify the potential for inelastic response. The bridge was subsequently analyzed in accordance with two nonlinear static analysis methods (capacity spectrum and inelastic demand spectrum methods) in an effort to evaluate the difference in global response predicted by the two methods and the effectiveness of various software programs for performing nonlinear static analysis. The results demonstrated that, for the two nonlinear static analysis methods used in this study, different predictions of nonlinear response occurred with neither method being regarded as producing correct results due to a number of simplifications inherent in the methods. Furthermore, the analysis revealed that some software programs are well suited to performing nonlinear static analysis, both from the point-of-view of performing comprehensive analyses and providing a graphical depiction of the evolution of damage (i.e. the behaviour of plastic hinges). 相似文献
57.
This study designs a robust closed‐loop control algorithm for elevated blood glucose level stabilisation in type 1 diabetic patients. The control algorithm is based on a novel control action resulting from integrating algebraic meal disturbance estimator with back‐stepping integral sliding mode control (BISMC) technique. The estimator shows finite time convergence leading to accurate and fast estimation of meal disturbance. Moreover, compensation of the estimated disturbance in controller provides significant reduction in chattering phenomenon, which is inherent drawback of sliding mode control (SMC). The controller is applied to one of the most reliable models of type 1 diabetic patients, named Bergman''s minimal model. The effectiveness and superiority of the designed controller is shown by comparing it to classical SMC and super‐twisting sliding mode control. The designed controller is subject to three different cases for detailed analysis of the controller''s robustness against meal disturbance. The three cases considered are hyperglycaemia, hyperglycaemia combined with meal disturbance and three meal disturbance. The simulation results confirm superior performance of algebraic disturbance estimator based BISMC controller for all the cases mentioned above.Inspec keywords: closed loop systems, robust control, sugar, medical control systems, variable structure systems, control system synthesis, blood, nonlinear control systems, adaptive control, diseasesOther keywords: adaptive robust control design, blood glucose regulation, type 1 diabetes patients, closed‐loop control algorithm, elevated blood glucose level stabilisation, type 1 diabetic patients, novel control action, algebraic meal disturbance estimator, mode control technique, accurate estimation, estimated disturbance, super‐twisting sliding mode control, algebraic disturbance estimator, BISMC controller, algebraic meal disturbance estimation, back‐stepping integral sliding mode control technique 相似文献
58.
Muhammad Awais Shahid Bashir Awais Khan Muhammad Asif Nasim Ullah Hend I. Alkhammash 《计算机、材料和连续体(英文)》2023,75(1):669-681
This paper presents a compact Multiple Input Multiple Output
(MIMO) antenna with WLAN band notch for Ultra-Wideband (UWB)
applications. The antenna is designed on 0.8 mm thick low-cost FR-4 substrate
having a compact size of 22 mm × 30 mm. The proposed antenna comprises
of two monopole patches on the top layer of substrate while having a shared
ground on its bottom layer. The mutual coupling between adjacent patches
has been reduced by using a novel stub with shared ground structure. The stub
consists of complementary rectangular slots that disturb the surface current
direction and thus result in reducing mutual coupling between two ports. A
slot is etched in the radiating patch for WLAN band notch. The slot is used
to suppress frequencies ranging from 5.1 to 5.9 GHz. The results show that the
proposed antenna has a very good impedance bandwidth of |S11| < −10 dB
within the frequency band from 3.1–14 GHz. A low mutual coupling of less
than −23 dB is achieved within the entire UWB band. Furthermore, the
antenna has a peak gain of 5.8 dB, low ECC < 0.002 and high Diversity Gain
(DG > 9.98). 相似文献
59.
A series of silatrane based imide resins having different end-caps were prepared by reacting 1-(3-aminopropyl)silatrane with 5-norbornene-endo-2,3-dicarboxylic anhydride (nadic anhydride), 5-methyl-5-norbornene-2,3-dicarboxylic anhydride (methyl nadic anhydride), hexachloronadic anhydride, maleic anhydride, benzophenone-3,3′,4,4′-tetracarboxylic dianhydride or pyromellitic dianhydride in dimethylacetamide. Structural characterisation of the resins was done by elemental analysis and IR. In DSC traces of these resins, an exothermic transition associated with crosslinking was observed above 230°C. Thermogravimetric studies revealed a multistep decomposition reaction. Residual weight at 800°C in nitrogen was found to depend on the backbone structure and ranged from 32–60%. 相似文献
60.
CT Garrett DS Liscia S Nasim A Ferreira-Gonzalez 《Canadian Metallurgical Quarterly》1995,15(4):957-971
Colorectal and breast cancers account for a significant number of deaths due to malignant neoplasia. Laboratory medicine plays an important role in the diagnosis and management of these tumors through the application of histopathology, immunohistochemistry, and serologic identification of tumor markers. Approximately 5% to 10% of colorectal and breast cancers result from an inherited predisposition. The genes responsible for most genetically transmitted cancers have been identified, and the application of findings from molecular pathology are being evaluated. This article reviews the genetic changes that occur as a result of somatic mutation and inherited or germline mutations. 相似文献