ABSTRACT
In recent years, plant extracts have been widely developed and used, but the pollution of heavy metals has threatened the safe application of plant extracts. Therefore, effective removal of heavy metal pollution in plant extracts has become an urgent problem to be solved and a research hotspot at home and abroad. At present, the widely used heavy metals removal technologies include flocculent precipitation, adsorption, molecular sieve and so on. Other new technologies and materials are also being applied to the removal of heavy metals from plant extracts, such as microbiological methods, nanotechnology, ion/molecular imprinting techniques, biomimetic materials, etc. This paper reviews the related literature about the principle and application of removal of heavy metals in plant extracts in recent years, summarizes the characteristics of each method, and prospects the development trends and prospects for the future.
ABSTRACT
This paper is to explore the feasibility of molecular sieve oxygen generator in the supply of oxygen in hospital. By introducing the different principles of oxygenation technology of pressure swing adsorption and oxygenation technology of heavy cooling, this article compared the merits of two ways in national regulations, safety, convenience, and economical efficiency. Oxygenation technology of pressure swing adsorption was more advanced, more automated and life-longer compared with cylinder oxygen supply and central oxygen supply. Molecular sieve oxygen generator is a new generation of oxygen generating equipment with a good application prospect, and can provide a better choice for hospital oxygen supply.
ABSTRACT
OBJECTIVE:To prepare mesopocous molecular sieve SBA-15 surface molecularly imprinted polymer (SBA-15@MIP),and analyze the application of SBA-15@MIP in the determination of active micro-component. METHODS:Using baica-lein as the template molecule,acrylamide(AM)as the function monomer,tetrahydrofuran/ethanol(3∶2,V/V)as the polymeriza-tion solvent,ethylene glycol dimethacrylate(EGDMA)as the cross-linker,and 2,2-azobisisobutyronitrile(AIBN)as the initiator, SBA-15@MIP was synthesized on the surface of mesopocous molecular sieve SBA-15. The surface morphology and structure of the obtained polymer were characterized by TEM and FT-IR. Finally,the imprinted polymer was used as an adsorbent for solid-phase extraction (SPE) to detect baicalein in plasma samples by HPLC. RESULTS:It revealed that the well-ordered one-dimensional pore structure of SBA-15 was still preserved in the successful synthesized SBA-15@MIP,and baicalein molecule was imprinted suc-cessfully. The limit of detection(LOD)and limit of quantification(LOQ)for baicalein in plasma were 3.5 ng/ml and 11.6 ng/ml, respectively;the average recovery was 94.4%(RSD=2.9%). CONCLUSIONS:SBA-15@MIP is prepared successfully,and can be applied for the determination of active micro-component.
ABSTRACT
The purpose of this study was to estimate internal motion using molecular sieve for quantitative improvement of lung tumor and to localize lung tumor in the small animal PET image by evaluated data. Internal motion has been demonstrated in small animal lung region by molecular sieve contained radioactive substance. Molecular sieve for internal lung motion target was contained approximately 37 kBq Cu-64. The small animal PET images were obtained from Siemens Inveon scanner using external trigger system (BioVet). SD-Rat PET images were obtained at 60 min post injection of FDG 37 MBq/0.2 mL via tail vein for 20 min. Each line of response in the list-mode data was converted to sinogram gated frames (2~16 bin) by trigger signal obtained from BioVet. The sinogram data was reconstructed using OSEM 2D with 4 iterations. PET images were evaluated with count, SNR, FWHM from ROI drawn in the target region for quantitative tumor analysis. The size of molecular sieve motion target was 1.59x2.50 mm. The reference motion target FWHM of vertical and horizontal was 2.91 mm and 1.43 mm, respectively. The vertical FWHM of static, 4 bin and 8 bin was 3.90 mm, 3.74 mm, and 3.16 mm, respectively. The horizontal FWHM of static, 4 bin and 8 bin was 2.21 mm, 2.06 mm, and 1.60 mm, respectively. Count of static, 4 bin, 8 bin, 12 bin and 16 bin was 4.10, 4.83, 5.59, 5.38, and 5.31, respectively. The SNR of static, 4 bin, 8 bin, 12 bin and 16 bin was 4.18, 4.05, 4.22, 3.89, and 3.58, respectively. The FWHM were improved in accordance with gate number increase. The count and SNR were not proportionately improve with gate number, but shown the highest value in specific bin number. We measured the optimal gate number what minimize the SNR loss and gain improved count when imaging lung tumor in small animal. The internal motion estimation provide localized tumor image and will be a useful method for organ motion prediction modeling without external motion monitoring system.
Subject(s)
Animals , Lung , VeinsABSTRACT
Objective To analyze the performance of adsorbing CO2 with zeolite 5A molecular sieve in crew module. Methods Fitting analysis was based on experimental data of adsorbing CO2,O2 and N2 with zeolite 5A molecular sieve and the suitability of isotherm adsorbing equation of Langmuir,Freundlich and BET models to be conducted with Origin software. Then using obtained equations and competitive adsorbing theory,the adsorbed amounts of these three kinds of gas under competitive condition were calculated. Results The constants in equations for adsorbing CO2,O2 and N2 with zeolite 5A molecular sieve were determined,and adsorbed amounts for above three kinds of gases under competitive condition were calculated. Conclusion The adsorbed CO2 amount is affected by high fraction of N2. Therefore zeolite 5A molecular sieve should be modified technically so that its adsorption in N2 might be reduced to an ignored amount.
ABSTRACT
Objective To establish a numerical model of adsorption and desorption of CO_2 and to study the influencing factors on the removal system. Method A physical model was expressed by mathematical method, then an isothermal adsorption model for simulating molecular sieve was established. Result The working process of a CO_2 removed device was simulated and its result was analized with the established model.The characteristics of the adsorption and desorption was obtained. Conclusion The model describes the processes correctly, the influencing factors like humidity dimension of the bed are considered simultaneously.It remains to be improved by further experimental corrections.