Improved performance of a chitosan-based adsorbent for the sequestration of some transition metals

2001 ◽  
Vol 43 (11) ◽  
pp. 9-16 ◽  
Author(s):  
R. R. Navarro ◽  
K. Tatsumi
Keyword(s):  
Graft Polymerization ◽  
Physical Stability ◽  
Three Dimensional ◽  
Batch Adsorption ◽  
Capacity Enhancement ◽  
Modified Chitosan ◽  
Coordination Requirements ◽  
Acidic Conditions ◽  
Improved Performance ◽  
Chitosan Resin

Polyethyleneimine (PEI) was chemically introduced onto chitosan by its reaction with epoxide groups of grafted poly(glycidyl methacrylate) (poly(GMA)) chains for enhanced metal chelating properties and improved physical stability in acidic conditions. Graft polymerization of poly(GMA) onto chitosan was initiated by Ce(IV) ammonium nitrate (CAN). Infrared spectroscopy revealed the presence of significant epoxide groups to confirm the success of both grafting and amination stages. Batch adsorption experiments showed the higher affinity of the modified chitosan resin for Cu2+, Zn2+ and Pb2+. The capacity enhancement was even more pronounced in the case of Zn2+ and Pb2+, which exhibits more complicated three dimensional coordination requirements. Optimum metal adsorption occurs at above pH 4. Regeneration of the resin with sulphuric acid-ammonium sulphate was also found to be feasible.

Au-modified three-dimensional In2O3 inverse opals: synthesis and improved performance for acetone sensing toward diagnosis of diabetes

Nanoscale ◽  
2015 ◽  
Vol 7 (30) ◽  
pp. 13051-13060 ◽  
Author(s):  
Ruiqing Xing ◽  
Qingling Li ◽  
Lei Xia ◽  
Jian Song ◽  
Lin Xu ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Exhaled Breath ◽  
Au Nps ◽  
Inverse Opals ◽  
Improved Performance

3DIO macroporous In2O3 films with additional via-hole architectures were fabricated and Au NPs were loaded, which were applied for detecting of acetone gas in exhaled breath.

scholarly journals Visual perception of the physical stability of asymmetric three-dimensional objects

2013 ◽  
Vol 13 (4) ◽  
pp. 12-12 ◽  
Author(s):  
S. A. Cholewiak ◽  
R. W. Fleming ◽  
M. Singh
Keyword(s):  
Visual Perception ◽  
Physical Stability ◽  
Three Dimensional ◽  
Three Dimensional Objects

scholarly journals Perception of Physical Stability of Asymmetrical Three-Dimensional Objects

2011 ◽  
Vol 11 (11) ◽  
pp. 44-44
Author(s):  
S. A. Cholewiak ◽  
M. Singh ◽  
R. Fleming
Keyword(s):  
Physical Stability ◽  
Three Dimensional ◽  
Three Dimensional Objects

scholarly journals Untargeted Metabolomic Profile for the Detection of Prostate Carcinoma—Preliminary Results from PARAFAC2 and PLS–DA Models

Molecules ◽  
2019 ◽  
Vol 24 (17) ◽  
pp. 3063 ◽  
Author(s):  
Amante ◽  
Salomone ◽  
Alladio ◽  
Vincenti ◽  
Porpiglia ◽  
...  
Keyword(s):  
Specific Antigen ◽  
Three Dimensional ◽  
Classification Model ◽  
Variables Selection ◽  
Electron Impact Mass ◽  
Full Scan ◽  
Acidic Conditions ◽  
New Biomarkers ◽  
Targeted Approach ◽  
Impact Mass

Prostate-specific antigen (PSA) is the main biomarker for the screening of prostate cancer (PCa), which has a high sensibility (higher than 80%) that is negatively offset by its poor specificity (only 30%, with the European cut-off of 4 ng/mL). This generates a large number of useless biopsies, involving both risks for the patients and costs for the national healthcare systems. Consequently, efforts were recently made to discover new biomarkers useful for PCa screening, including our proposal of interpreting a multi-parametric urinary steroidal profile with multivariate statistics. This approach has been expanded to investigate new alleged biomarkers by the application of untargeted urinary metabolomics. Urine samples from 91 patients (43 affected by PCa; 48 by benign hyperplasia) were deconjugated, extracted in both basic and acidic conditions, derivatized with different reagents, and analyzed with different gas chromatographic columns. Three-dimensional data were obtained from full-scan electron impact mass spectra. The PARADISe software, coupled with NIST libraries, was employed for the computation of PARAFAC2 models, the extraction of the significative components (alleged biomarkers), and the generation of a semiquantitative dataset. After variables selection, a partial least squares–discriminant analysis classification model was built, yielding promising performances. The selected biomarkers need further validation, possibly involving, yet again, a targeted approach.

Synthesis of Modified Chitosan with Thiamine Hydrochloride as the Adsorbent for Calcium (II) Ion Removal

2019 ◽  
Vol 798 ◽  
pp. 397-403
Author(s):  
Ratana Sananmuang
Keyword(s):  
Calcium Ions ◽  
Water Hardness ◽  
Batch Adsorption ◽  
Thiamine Hydrochloride ◽  
Modified Chitosan ◽  
Ion Removal ◽  
Effective Removal ◽  
Optimum Ph ◽  
Langmuir Isotherm Model ◽  
Nmr Techniques

Water quality is very important to food processing industry. Water hardness caused by calcium ions in water can affect the properties of food including aroma, texture, flavor and appearance. Chitosan has amino functional groups that can remove metal ions from aqueous solution. However, chitosan can give more effective removal of calcium ions if it is modified with functionalized substance such as thiamine hydrochloride. therefore, the objectives of this study were to synthesize the modified chitosan with thiamine hydrochloride (MCTH) and to determine its efficiency for removal of calcium ion in solution. Chitosan was prepared from crab shells and modified with thiamine hydrochloride at 30 °C. The morphology of both crab-shell chitosan (CSC) and MCTH was characterized by SEM, FTIR and NMR techniques. Batch adsorption experiments were conducted as a function of pH, contacted time and initial concentration of calcium (II) ions. The desorption of calcium(II) ion from both adsorbents was also investigated. The concentration of calcium in solution was measured by FAAS technique. The results indicated that the optimum pH for adsorption was 6.0 for both CSC and MCTH. The adsorption capacity for MCTH (48.31 mg g-1) was greater than that of CSC (1.52 mg g-1). The isotherm showed that the adsorption process of calcium (II) ions onto MCTH was fitted to Langmuir isotherm model. Calcium desorption from MCTH was lower than that of CSC.

scholarly journals TransformerCPI: improving compound–protein interaction prediction by sequence-based deep learning with self-attention mechanism and label reversal experiments

2020 ◽  
Vol 36 (16) ◽  
pp. 4406-4414 ◽  
Author(s):  
Lifan Chen ◽  
Xiaoqin Tan ◽  
Dingyan Wang ◽  
Feisheng Zhong ◽  
Xiaohong Liu ◽  
...  
Keyword(s):  
Protein Interaction ◽  
Three Dimensional ◽  
Prediction Performance ◽  
Dimensional Structure ◽  
Sequence Information ◽  
Biological Targets ◽  
Interaction Prediction ◽  
Protein Interaction Prediction ◽  
Improved Performance ◽  
Ligand Bias

Abstract Motivation Identifying compound–protein interaction (CPI) is a crucial task in drug discovery and chemogenomics studies, and proteins without three-dimensional structure account for a large part of potential biological targets, which requires developing methods using only protein sequence information to predict CPI. However, sequence-based CPI models may face some specific pitfalls, including using inappropriate datasets, hidden ligand bias and splitting datasets inappropriately, resulting in overestimation of their prediction performance. Results To address these issues, we here constructed new datasets specific for CPI prediction, proposed a novel transformer neural network named TransformerCPI, and introduced a more rigorous label reversal experiment to test whether a model learns true interaction features. TransformerCPI achieved much improved performance on the new experiments, and it can be deconvolved to highlight important interacting regions of protein sequences and compound atoms, which may contribute chemical biology studies with useful guidance for further ligand structural optimization. Availability and implementation https://github.com/lifanchen-simm/transformerCPI.

scholarly journals Improved performance of stellarator coil design optimization

2020 ◽  
Vol 86 (2) ◽  
Author(s):  
Jim-Felix Lobsien ◽  
Michael Drevlak ◽  
Thomas Kruger ◽  
Samuel Lazerson ◽  
Caoxiang Zhu ◽  
...  
Keyword(s):  
Stochastic Optimization ◽  
Design Optimization ◽  
Three Dimensional ◽  
Local Maximum ◽  
Average Field ◽  
Test Case ◽  
Coil Design ◽  
Applied Optimization ◽  
Improved Performance ◽  
Coil Shape

Following up on earlier work which demonstrated an improved numerical stellarator coil design optimization performance by the use of stochastic optimization (Lobsien et al., Nucl. Fusion, vol. 58 (10), 2018, 106013), it is demonstrated here that significant further improvements can be made – lower field errors and improved robustness – for a Wendelstein 7-X test case. This is done by increasing the sample size and applying fully three-dimensional perturbations, but most importantly, by changing the design sequence in which the optimization targets are applied: optimization for field error is conducted first, with coil shape penalties only added to the objective function at a later step in the design process. A robust, feasible coil configuration with a local maximum field error of 3.66 % and an average field error of 0.95 % is achieved here, as compared to a maximum local field error of 6.08 % and average field error of 1.56 % found in our earlier work. These new results are compared to those found without stochastic optimization using the FOCUS and ONSET suites. The relationship between local minima in the optimization space and coil shape penalties is also discussed.

Identification of Wake Convection and Flow Outline in the Interface Region of Blade Rows With Axial Gap in a Counter Rotating Turbine

2019 ◽  
Author(s):  
Rayapati Subbarao ◽  
M. Govardhan
Keyword(s):  
Flow Pattern ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Three Dimensional ◽  
Interface Region ◽  
Turbine Stage ◽  
Deviation Angle ◽  
Flow Rates ◽  
Improved Performance

Abstract In a Counter Rotating Turbine (CRT), the stationary nozzle is trailed by two rotors that rotate in the opposite direction to each other. Flow in a CRT stage is multifaceted and more three dimensional, especially, in the gap between nozzle and rotor 1 as well as rotor 1 and rotor 2. By varying this gap between the blade rows, the flow and wake pattern can be changed favorably and may lead to improved performance. Present work analyzes the aspect of change in flow field through the interface, especially the wake pattern and deviation in flow with change in spacing. The components of turbine stage are modeled for different gaps between the components using ANSYS® ICEM CFD 14.0. Normalized flow rates ranging from 0.091 to 0.137 are used. The 15, 30, 50 and 70% of the average axial chords are taken as axial gaps in the present analysis. CFX 14.0 is used for simulation. At nozzle inlet, stagnation pressure boundary condition is used. At the turbine stage or rotor 2 outlet, mass flow rate is specified. Pressure distribution contours at the outlets of the blade rows describe the flow pattern clearly in the interface region. Wake strength at nozzle outlet is more for the lowest gap. At rotor 1 outlet, it is less for x/a = 0.3 and increases with gap. Incidence angles at the inlets of rotors are less for the smaller gaps. Deviation angle at the outlet of rotor 1 is also considered, as rotor 1-rotor 2 interaction is more significant in CRT. Deviation angle at rotor 1 outlet is minimum for this gap. Also, for the intermediate mass flow rate of 0.108, x/a = 0.3 is giving more stage performance. This suggests that at certain axial gap, there is better wake convection and flow outline, when compared to other gap cases. Further, it is identified that for the axial gap of x/a = 0.3 and the mean mass flow rate of 0.108, the performance of CRT is maximum. It is clear that the flow pattern at the interface is changing the incidence and deviation with change in axial gap and flow rate. This study is useful for the gas turbine community to identify the flow rates and gaps at which any CRT stage would perform better.

Three-Dimensional Flowfields Inside a Transonic Compressor With Swept Blades

1991 ◽  
Vol 113 (2) ◽  
pp. 241-250 ◽  
Author(s):  
C. Hah ◽  
A. J. Wennerstrom
Keyword(s):  
Turbulence Modeling ◽  
Three Dimensional ◽  
Secondary Flows ◽  
Operating Conditions ◽  
Tip Clearance ◽  
Navier Stokes ◽  
Navier Stokes Equation ◽  
Tip Clearance Flow ◽  
Transonic Compressor ◽  
Improved Performance

The concept of swept blades for a transonic or supersonic compressor was reconsidered by Wennerstrom in the early 1980s. Several transonic rotors designed with swept blades have shown very good aerodynamic efficiency. The improved performance of the rotor is believed to be due to reduced shock strength near the shroud and better distribution of secondary flows. A three-dimensional flowfield inside a transonic rotor with swept blades is analyzed in detail experimentally and numerically. A Reynolds-averaged Navier–Stokes equation is solved for the flow inside the rotor. The numerical solution is based on a high-order upwinding relaxation scheme, and a two-equation turbulence model with a low Reynolds number modification is used for the turbulence modeling. To predict flows near the shroud properly, the tip-clearance flow also must be properly calculated. The numerical results at three different operating conditions agree well with the available experimental data and reveal various interesting aspects of shock structure inside the rotor.

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