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排序方式: 共有217条查询结果,搜索用时 15 毫秒
111.
Van Thuan Le Thi Kieu Ngan Tran Dai Lam Tran Hoang Sinh Le Van Dat Doan Quang Dung Bui 《Journal of Dispersion Science and Technology》2013,34(12):1761-1776
AbstractIn the present work, a novel composite consisting of magnetite, activated carbon from spent coffee grounds and natural clay (MACCC) was prepared by a one-pot synthesis method via a simultaneous activation and magnetization processes. Various techniques (XRD, FTIR, SEM, TEM, EDX, BET) were utilized to characterize the synthesized composite before utilizing it as an adsorbent for removal of Cu(II), Ni(II) and Pb(II) ions from aqueous solutions. Conditions for removal of heavy metals were thoroughly optimized as 25?°C, pH of 5.5, adsorbent dosage of 2?g L?1, and a contact time of 60?min. Three models of pseudo first-, second-order and intraparticle diffusion as well as three models of Langmuir, Freundlich, and Temkin were used to analyze kinetics and isotherms of the adsorption process. Thermodynamics was discussed completely. Regeneration and recyclability of the adsorbent were also evaluated. Based on the analysis of experimental results, a possible adsorption mechanism of heavy metals onto the synthesized composite was proposed. The maximum capacities caculated from Langmuir model followed the order of Pb(II) > Cu(II) > Ni(II) as 143.56, 96.16 and 84.86?mg·g?1, respectively. The overall results indicated that MACCC is a potential adsorbent for removal of toxic Pb(II), Cu(II) and Ni(II) ions from wastewater due to simple preparation, high removal efficiency and good recyclability. 相似文献
112.
Uyen Tu Thi Doan Duy Khanh Le Truong Lam Huynh Tung Thanh Ngo Trieu Quang Vo Dr. Minh Thu Tran Thi Anh Tuan Thanh Pham Vinh Cao Tran Phuong Tuyet Nguyen Ngoc Kim Pham 《Chemphyschem》2023,24(18):e202300210
In this study, the features of resistive random access memory (RRAM) employing a straightforward Cr/MAPbI3/FTO three-layer structure have been examined and clarified. The device displays various resistance switching (RS) behavior at various sweep voltages between 0.5 and 5 V. The RS effect has a conversion in the direction of the SET and RESET processes during sweeping for a number of cycles at a specific voltage. The directional change of the RS processes corresponds to the dominant transition between the generation/recombination of iodide ion and vacancy in the MAPbI3 perovskite layer and the electrochemical metallization of the Cr electrode under the influence of an electric field, which results in the conductive filament (CF) formation/rupture. At each stage, these processes are controlled by specific charge conduction mechanisms, including Ohmic conduction, space-charge-limited conduction (SCLC), and variable-range hopping (VRH). By identifying the biased voltage and the quantity of voltage sweep cycles, one can take a new approach to control or modulate the pathways for effective charge transport. This new approach is made possible by an understanding of the RS characteristics and the corresponding mechanisms causing the variation of RS behavior in the structure. 相似文献
113.
Thi-Hanh Nguyen San-Lang Wang Dai-Nam Nguyen Anh-Dzung Nguyen Thi-Huyen Nguyen Manh-Dung Doan Van-Anh Ngo Chien-Thang Doan Yao-Haur Kuo Van-Bon Nguyen 《Molecules (Basel, Switzerland)》2021,26(11)
Recently, microbial prodigiosin (PG) has received much attention due to its numerous beneficial applications. The aim of this study was to establish the bioprocessing of marine chitinous wastes (MCWs) for the cost-effective preparation of PG. Of the MCWs, demineralized shrimp shell powders (de-SSP) were found to be a potential source of carbon/nitrogen (C/N) for PG production by bacterial fermentation using Serratia marcescens strains. Further, PG scale-up production was investigated in a 15 L bioreactor system, and the highest yield (6200 mg/L) was achieved during fermentation using 5 L of a novel-designed culture broth that included 1.60% C/N sources (a de-SSP/casein ratio of 7/3), 0.02% K2SO4, and 0.05% K2HPO4, with an initial pH of 6–7. Fermentation was conducted in the dark at 27.5 °C for 8.0 h. This study was the first to report on the utilization of shrimp wastes for cost-effective, large-scale (5 L/pilot) PG production with high productivity (6200 mg/L) in a short cultivation time. The combination of 0.02% K2SO4 and 0.05% K2HPO4 was also found to be a novel salt composition that significantly enhanced PG yield. The red compound was purified and confirmed as PG after analyzing its HPLC profile, mass, and UV/vis spectra. The purified PG was then tested for its bioactivities and showed effective anticancer activities, moderated antioxidant activities, and novel anti-NO effects. 相似文献
114.
115.
Micro-electrodialysis (μED) and CE were combined for rapid pretreatment and subsequent determination of inorganic cations in biological samples. Combination of μED with CE greatly improved the analytical performance of the latter as the adsorption of high molecular weight compounds present in real samples on the inner capillary wall was eliminated. Fifty microliter of 80-fold diluted human body fluids such as plasma, serum and whole blood was used in the donor compartment of the μED system requiring less than 1?μL of the original body fluid per analysis. Inorganic cations that migrated through a cellulose acetate dialysis membrane with molecular weight cut-off value of 500?Da were collected in the acceptor solution and were then analyzed using CE-C?D. Baseline separation of inorganic cations was achieved in a BGE solution consisting of 12.5?mM maleic acid, 15?mM L-arginine and 3?mM 18-crown-6 at pH 5.5. Repeatability of the CE-C?D method was better than 0.5% and 2.5% for migration times and peak areas, respectively; limits of detection of all inorganic cations in the presence of 2?mM excess of Na(+) were around 1?μM and calibration curves were linear with correlation coefficients better than 0.998. Repeatability of the sample pretreatment procedure was calculated for six independent electrodialysis runs of artificial and real samples and was better than 11.8%. Recovery values between 96.3 and 110% were achieved for optimized electrodialysis conditions of standard solutions and real samples; lifetime of the dialysis membranes for pretreatment of real samples was estimated to 100 runs. 相似文献
116.
Thai Doan Chuong 《Nonlinear Analysis: Theory, Methods & Applications》2011,74(17):6256-6264
The aim of this work is twofold. First, we use the advanced tools of modern variational analysis and generalized differentiation to study the Lipschitz-like property of an implicit multifunction. More explicitly, new sufficient conditions in terms of the Fréchet coderivative and the normal/Mordukhovich coderivative of parametric multifunctions for this implicit multifunction to have the Lipschitz-like property at a given point are established. Then we derive sufficient conditions ensuring the Lipschitz-like property of an efficient solution map in parametric vector optimization problems by employing the above implicit multifunction results. 相似文献
117.
Knehans T Schüller A Doan DN Nacro K Hill J Güntert P Madhusudhan MS Weil T Vasudevan SG 《Journal of computer-aided molecular design》2011,25(3):263-274
An in silico fragment-based drug design approach was devised and applied towards the identification of small molecule inhibitors of the
dengue virus (DENV) NS2B-NS3 protease. Currently, no DENV protease co-crystal structure with bound inhibitor and fully formed
substrate binding site is available. Therefore a homology model of DENV NS2B-NS3 protease was generated employing a multiple
template spatial restraints method and used for structure-based design. A library of molecular fragments was derived from
the ZINC screening database with help of the retrosynthetic combinatorial analysis procedure (RECAP). 150,000 molecular fragments
were docked to the DENV protease homology model and the docking poses were rescored using a target-specific scoring function.
High scoring fragments were assembled to small molecule candidates by an implicit linking cascade. The cascade included substructure
searching and structural filters focusing on interactions with the S1 and S2 pockets of the protease. The chemical space adjacent
to the promising candidates was further explored by neighborhood searching. A total of 23 compounds were tested experimentally
and two compounds were discovered to inhibit dengue protease (IC50 = 7.7 μM and 37.9 μM, respectively) and the related West Nile virus protease (IC50 = 6.3 μM and 39.0 μM, respectively). This study demonstrates the successful application of a structure-guided fragment-based
in silico drug design approach for dengue protease inhibitors providing straightforward hit generation using a combination of homology
modeling, fragment docking, chemical similarity and structural filters. 相似文献
118.
Nguyen SD Yeon J Kim SH Halasyamani PS 《Journal of the American Chemical Society》2011,133(32):12422-12425
A new noncentrosymmetric (NCS) and polar material containing two lone-pair cations, Bi(3+) and I(5+), and exhibiting an Aurivillius-type (Bi(2)O(2))(2+) layer has been synthesized and structurally characterized. The material, BiO(IO(3)), exhibits strong second-harmonic generation (SHG), ~12.5 × KDP (or ~500 × α-SiO(2)), using 1064 nm radiation, and is found in the NCS polar orthorhombic space group Pca2(1) (No. 29). The structure consists of (Bi(2)O(2))(2+) cationic layers that are connected to (IO(3))(-) anions. The macroscopic polarity, observed along the c-axis direction, may be attributed to the alignment of the IO(3) polyhedra. In addition to the crystal structure and SHG measurements, polarization and piezoelectric measurements were performed, as well as electronic structure analysis. 相似文献
119.
120.
Pham Van Toi Khanh V. Doan Ngo Ngọc Quang Minh Pham Nguyen Phuong Menno D. de Jong H. Rogier van Doorn Thomas Pouplin 《Biomedical chromatography : BMC》2020,34(1):e4699
In this study, we developed and validated two reliable high-performance liquid chromatography (HPLC) methods for the qualitative detection of six oral β-lactams, which are commonly used in pediatric patients with acute respiratory infections (ARIs). Two distinct reverse-phase chromatographic separations of six β-lactams were obtained. Four β-lactams (cefadroxil, cephalexin, cefaclor and cefixime) in urine were separated using a gradient program with a mobile phase consisting of K2HPO4 buffer (20 mm , pH 2.8) and acetonitrile on a LichroCART 250 × 4.6 mm, Purospher STAR C18 end-capped (5 μm) column. Two remained β-lactams (amoxicillin and cefuroxime) were analyzed using a gradient elution with the mobile phase containing K2HPO4 buffer (20 mm , pH 3.0) and acetonitrile on a LichroCart® Purospher Star C8 end-capped column (5 μm, 125 × 4.6 mm). Good linearity within the range of 0.3–30 μg/ml for cefadroxil, cephalexin, cefaclor and cefixime, and 0.2–20 μg/ml for amoxicillin and cefuroxime, was attained. The precisions were <14%. The accuracies ranged from 85.87 to 102.8%. The two validated methods were then applied to determine these six antibiotics in 553 urine samples of pediatric patients with ARIs. As a result, 32.2% were positive with one or more of six tested β-lactams. Cefixime was the most commonly detected agent, accounting for 9.8% of enrolled patients. 相似文献