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مرکز اطلاعات علمی SID1
اسکوپوس
دانشگاه غیر انتفاعی مهر اروند
ریسرچگیت
strs
Issue Info: 
  • Year: 

    2017
  • Volume: 

    7
  • Issue: 

    2
  • Pages: 

    103-109
Measures: 
  • Citations: 

    0
  • Views: 

    129455
  • Downloads: 

    53259
Abstract: 

An efficient four-component synthesis of benzopyranopyridines is described by one-pot condensation of salicylaldehydes, thiols and 2 equiv of malononitrile with nano-PbWO4 as a robust and reusable heterogeneous catalyst under ULTRASONIC IRRADIATION. Lead tungstate (PbWO4) nanostructures have been synthesized via a sonochemical method based on the reaction between lead (II) nitrate and sodium tungstate dihydrate in an aqueous solution. Some advantages of this protocol include use of simple and readily available starting materials, rapid assembly of medicinally privileged heterocyclic molecules, reusability of the catalyst, low amount of the catalyst and application of the sonochemical methodology as an efficient technique and innocuous means of activation in synthetic chemistry.

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Issue Info: 
  • Year: 

    2019
  • Volume: 

    13
  • Issue: 

    2
  • Pages: 

    81-88
Measures: 
  • Citations: 

    0
  • Views: 

    73648
  • Downloads: 

    45999
Abstract: 

A highly efficient and convenient procedure for the enantioselective synthesis of (S)-Rivastigmine tartrate, a cholinergic agent for the treatment of mild to moderate dementia of the Alzheimer’ s disease, is accomplished by the treatment of versatile, readily accessible N-Ethyl-N-methyl carbamoyl chloride with 3-hydroxyacetophenone under ULTRASONIC IRRADIATION in presence of nano-K2CO3were reported. This protocol provided a high yielding stereoselective and short synthesis of (S)-Rivastigmine tartrate with an overall isolated yield of 83%. All the starting reagents and catalyst are inexpensive and commercially available. Compared to conventional heating which provides thermal energy in the macro system, ultra sonification reduces reaction times, improves yields and minimizes side product formation by providing the activation energy in micro environment. As this technology involves energy conservation and minimal waste generation, it is widely accepted as a green chemistry approach. The reported strategy afforded under ULTRASONIC IRRADIATION and in presence of Nano-K2CO3 via four steps, which (to the best of our knowledge) depicts the shortest and the most rapid method to enantiopure Rivastigmine tartrate reported to date.

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Author(s): 

RANJBAR KARIMI R. | AZIZI H.

Issue Info: 
  • Year: 

    2017
  • Volume: 

    3
  • Issue: 

    2
  • Pages: 

    132-138
Measures: 
  • Citations: 

    0
  • Views: 

    61203
  • Downloads: 

    30405
Abstract: 

Some aryl and heteroaryl azido compounds were synthesized from the reaction of the corresponding fluoro and chloro compounds with sodium azide in DMF as solvent and under various reaction conditions especially ULTRASONIC IRRADIATION. Reaction of aromatic and heteroaromatic azido compound with thioacetic acid in the presence of sodium hydrogen carbonate and in methanol as solvent led to the different products. Further intermolecular nucleophilic aromatic substitution reaction ofN - (perfluoropyridin4-yl) acetamid allow the regioselective synthesis of 2, 6, 7-trifluoro-2-methyloxazolo [4, 5-c] pyridine. The structures of all compounds were confirmed by IR, 1H NMR and 13C NMR spectroscopy as well as elemental analysis.

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گارگاه ها آموزشی
Issue Info: 
  • Year: 

    2019
  • Volume: 

    9
  • Issue: 

    4
  • Pages: 

    768-775
Measures: 
  • Citations: 

    0
  • Views: 

    40086
  • Downloads: 

    17472
Abstract: 

Synthesis and characterization of Cd-TiO2/PEG/FA nanocomposite as a biomaterial is the main aim of this research. Cd-doped TiO2 nanoparticles (NPs) were synthesized by solvothermal assisted sol-gel method. Then, polyethylene glycol (PEG) was added to the as-synthesized NPs to modify their surface and to prevent agglomeration. In the next step, folic acid (FA) was conjugated to Cd-TiO2/PEG nanocomposite. Optimization of FA concentration and infl uence of ultraviolet (UV) radiation, visible light, or ULTRASONIC IRRADIATION on antibacterial activity of the synthesized nanocomposite were assessed. Results showed that the influence of FA on the antibacterial performance of the as-synthesized compounds is positive and dose-dependent. FA was used as bait for bacteria and led them to accumulate around the Cd-TiO2 NPs. The bactericidal response under UV or visible light IRRADIATION was maximized at 0. 6 weight ratio of FA to CdTiO2, whereas, this parameter under ULTRASONIC IRRADIATION was improved and then became approximately constant.

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Journal: 

LASER IN MEDICINE

Issue Info: 
  • Year: 

    2011
  • Volume: 

    8
  • Issue: 

    3 (41)
  • Pages: 

    28-33
Measures: 
  • Citations: 

    0
  • Views: 

    541
  • Downloads: 

    257
Abstract: 

Background: Chemo mechanical debridement is an important part of endodontic treatment. Elimination of pulpal tissue, microbiota and their by-products, organic and inorganic debris removal by using instruments and intracanal irrigants are objectives of this important phase of treatment. The aim of this study was to ex-vivo evaluation of smear layer removal in conventional clinical methods, Passive ULTRASONIC Irrigation, Laser Activated Irrigation.Material and Methods: 54 anterior mandibular teeth was used in this study. After preparation of samples, they were divided in to 3 groups of Conventional Irrigation +Smear layer removal, Passive ULTRASONIC Irrigation, Laser Activated Irrigation. Then, the samples were cut longitudinally in mesiodistal direction for examination by SEM (1500X) for assessing smear layer removal.Results: In coronal, middle and apical one third, the best result was obtained from Conventional Irrigation + Smear layer removal group for smear layer removal.Conclusion: According to better smear layer removal in Conventional Irrigation + Smear layer, it is considered as gold standard protocol and other groups cannot be a suitable substitution for this method.

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Issue Info: 
  • Year: 

    2015
  • Volume: 

    6
  • Issue: 

    4
  • Pages: 

    363-369
Measures: 
  • Citations: 

    0
  • Views: 

    155791
  • Downloads: 

    44587
Abstract: 

This work reports a facile sonochemical route in the synthesis of nano particle of deferasirox for the first time. One application of nanotechnology is in improvement of available treatments for various diseases. Deferasirox (ICL670 or Exjade) is a tridentate chelating agent for removing transfusion overload iron in thalassemia patients. In the present work, deferasirox was prepared in nano size by using of ultrasound waves. The effects of amount and reaction time on the size of deferasirox were investigated. These parameters were optimized at various amounts and different reaction times. Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) studies show that the deferasirox in nature structure does not change during the reaction. The results show that the finest particle is related to the following conditions: 45min, time reaction and 0.1g, amount of deferasirox. Therefore, the ULTRASONIC bath method has a fundamental role in the preparation of deferasirox in nano scale. This method is simple, relatively fast and low cost.

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strs
Author(s): 

NIE MIN | XIA HESHENG | WU JINKUI

Issue Info: 
  • Year: 

    2013
  • Volume: 

    22
  • Issue: 

    6
  • Pages: 

    409-416
Measures: 
  • Citations: 

    0
  • Views: 

    76086
  • Downloads: 

    32495
Keywords: 
Abstract: 

Polymeric composite materials filled with single-walled carbon nanotubes (SWNTs) have attracted much attention, but successful applications of such composites require uniform dispersion of SWNTs in the polymeric matrix and the strong SWNTs-polymer interface interaction. In this paper, chemical modification combined with ULTRASONICally initiated in situ polymerization was successfully employed to prepare poly(styrene-co-butyl acrylate)/single-walled carbon nanotubes composites [P(St-BA)/SWNTs]. The whole procedure contained two steps: in the first step, 3-(trimethoxy)-propylmethacrylate-silane (silane-coupling agent, KH570), a kind of polymerizable vinyl monomer, was grafted onto the surface of SWNTs, forming KH570-g-SWNTs by reacting KH570 with hydroxyl groups on the surface of SWNTs, which was proved by combination of FTIR and XPS results. Due to the presence of polymerizable KH570 on the surface of SWNTs, this provides a basis for the next stage of polymerization to prepare polymer-encapsulated SWNTs composites. In the second step, an ULTRASONICally initiated in situ emulsion polymerization of monomer styrene (St) and n-butyl acrylate (BA) proceeded in the presence of KH570-g-SWNTs. Consequently, P(St-BA)/SWNTs composite emulsion was obtained. TEM confirmed that SWNTs were coated with the obtained polymer. FTIR and XPS further showed that even after 72 h of soxhlet extraction with boiling toluene, there were still unextracted polymers in P(St-BA)/SWNTs composite, indicating strong interaction between the polymer and carbon nanotubes. Finally, a mechanism for formation of polymer-encapsulated SWNTs through ULTRASONICally initiated in situ emulsion polymerization was proposed. This study could provide a new way to resolve the problems of the dispersion, stabilization, and compositing of SWNTs with polymer matrix and prepare polymer/SWNTs composites.

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Author(s): 

Journal: 

PROCEDIA ENGINEERING

Issue Info: 
  • Year: 

    2017
  • Volume: 

    170
  • Issue: 

    -
  • Pages: 

    55-59
Measures: 
  • Citations: 

    422
  • Views: 

    9914
  • Downloads: 

    21919
Keywords: 
Abstract: 

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Author(s): 

NAZARZADEH ZAREH E.

Issue Info: 
  • Year: 

    2010
  • Volume: 

    4
  • Issue: 

    13
  • Pages: 

    83-91
Measures: 
  • Citations: 

    0
  • Views: 

    1116
  • Downloads: 

    752
Abstract: 

The aim of this work is to synthesis a polyaniline with high conductivity by chemical oxidative polymerization under ULTRASONIC IRRADIATION. The aniline chemical polymerization carried out by addition of initiator such an ammonium peroxydisulfate (APS) in aqueous medium under ULTRASONIC IRRADIATION in inert atmosphere. The influence of synthesis conditions such as the duration of reaction time, concentration of the oxidant, concentration of HCl and presence of air atmospher or inert gas in the obtained polyaniline were investigated.The optimum conditions for the synthesis of polyaniline with better conductivity were determined. Our results demonstrate that polyaniline conductivity depends on the conditions such as, concentration of HCl, presence of oxygen in the reaction medium and monomer molar ration of the initiator. The optimum molar ration of the initiator to the monomer aniline is 2.5:2 .The electrical conductivity of polyaniline synthesis by optimized condition was 23.46 S/cm measured at -5 - 0°C. The obtained polyaniline characterized by FT-IR, UV-Vis, XRD, DSC and SEM.

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Issue Info: 
  • Year: 

    2020
  • Volume: 

    33
  • Issue: 

    6 (TRANSACTIONS C: Aspects)
  • Pages: 

    1060-1069
Measures: 
  • Citations: 

    0
  • Views: 

    48322
  • Downloads: 

    19832
Abstract: 

In this study, nanoscale zero-valent copper (nZVC) as catalyst activated persulfate (PS) was used for the degradation of p-chlorophenol (p-CP) under ULTRASONIC (US) IRRADIATION in aqueous solution. The effect of different operational parameters such as solution pH (3. 5-10. 5), PS concentration (1-7. 5 mm/L), nZVC dosage (5-35 mg/L) and initial p-CP concentration (10-100 mg/L) were evaluated at different contact time. Results indicated that US/PS/nZVC system achieve higher efficiency in p-CP degradation than US/PS, US/nZVC and PS/nZVC systems. The optimal p-CP removal efficiency (98%) was achieved within 40 min with 5 mm/L PS and 30mg/L nanocatalyst at 25 mg/L initial p-CP concentration. It was also observed that the p-CP degradation rate depends on initial p-CP concentrations. To clarify the mineralization of p-CP, TOC and COD were analyzed at optimum conditions. COD and TOC removal rate obtained from the US/PS/nZVC system with contact time of 60 min were 61and 75%, respectively. Through the use of methanol (MA) and tert-butyl alcohol (TBA) as radical scavengers, SO4° − was identified as the main radical species that are generated during processes. The removal process of p-CP could be described by the pseudo-first-order kinetics. The apparent degradation rate constant (k) was 0. 076 min-1 in US/PS/nZVC system at optimal conditions.

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