A Continuation Method of Parameter Inversion for Non-Equilibrium Convection-Dispersion Equation

Based on the homotopy mapping, a globally convergent method of parameter inversion for non-equilibrium convection-dispersion equations （CDEs） is developed. Moreover, in order to further improve the computational efficiency of the algorithm, a properly smooth function, which is derived from the sigmoid function, is employed to update the homotopy parameter during iteration. Numerical results show the feature of global convergence and high performance of this method. In addition, even the measurement quantities are heavily contaminated by noises, and a good solution can be found.     

Dynamic equilibrium of ion exchange in the system lead-cation exchanger at different temperatures

Summary The relationship between the ion-exchange reaction in a column and temperature was examined in the system lead-ion exchanger resin Lewatit S 1080. Lead binding was performed with 0.01 mol/l HNO₃ and elution with 4.0 mol/l HCl. The working temperature was gradually increased from 273 to 333 K. Thermostat columns were of own construction. The results were statistically analysed and graphically presented and the parameters obtained for elution curves were related to temperature. The elution curves were found to be temperature specific. The parameters such as elution band width, distribution factor, maximal volume of the eluate, maximal lead concentration in the eluate, confirmed this fact. At higher temperatures, larger volumes of elution solution were required for the elution of the same quantity of lead.

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Ionenaustausch im System Blei-Kationischer Austauscher bei verschiedenen Temperaturen

     

A Construction of Partial Difference Sets in {\mathbb{Z}}_{p^{2 \times } } {\mathbb{Z}}_{p^{2 \times \cdot \cdot \cdot \times } } {\mathbb{Z}}_{p^2 }

In this paper, we give a construction of partial difference sets in _p ² x _p ² x ... x _p ²using some finite local rings.Dedicated to Hanfried Lenz on the occasion of his 80th birthdayThe work of this paper was done when the authors visited the University of Hong Kong.     

Convenient synthesis of arylpropargyl aldehydes and 4-aryl-3-butyn-2-ones from arylacetylenes and amide acetals

The reaction of arylacetylenes 1 and N,N-dimethylformamide dimethylacetal (2a, DMF-DMA) afforded the corresponding arylpropargyl aldehydes 3 in moderate yields. Similarly, the reaction of 1 and N,N-dimethylacetamide dimethylacetal (2b, DMA-DMA) gave 4-aryl-3-butyn-2-ones 4.     

Separation of silver from waste waters by ion-exchange resins and concentration by microbial cells

Summary Waste waters of film processing plants are rich with silver. Part of the silver is regenerated electrochemically, but the rest (0.5 g) remains in waste waters and is sent to sewers. This is a bad politic from both the environmental (toxic waste waters) and the economical point of view (a waste of silver). In this work, the silver was isolated by ion-exchange resins and then concentrated by microorganisms. For exchange of silver, Ionenaustauscher I, II and IV were used. The batch method was used to obtain a static equilibrium. Silver elution from exchangers is based on silver transformation to a stable cation or anion complex. By varying the ligands, pH and eluent concentrations, optimum elution is found at 1 mol/l Na₂S₂O₃, 1 mol/l NH₃, 2 mol/l HNO₃ and 1 mol/l (NH₂)₂CO. The concentration of silver in the eluent is about 50 mg/l. The silver ion uptake from solutions after ion exchange by mixed bacterial culture isolated from photographic waste water drain and pure bacterial cultures Escherichia coli 3009 and Bacillus subtilis 3053. was studied. Experiments were carried out in submerse culture at pH 7 with different Ag⁺ concentrations (4, 8 and 40 mg/l) on a rotary shaker (100 rpm) at 37°C. At the lower Ag⁺ concentrations a good growth and simultaneous removal of Ag⁺ from the solutions was achieved. At Ag⁺ concentration of 40 mg/l growth and removal of Ag⁺ by mixed and pure culture differed significantly. Thus mixed bacterial culture grew well and at the same time removed efficiently Ag⁺ (approximately 90%) from medium. Pure bacterial cultures on the contrary were unable to grow at 40 mg/l Ag⁺, though their biomass showed to be an effective biosorbent for Ag⁺ (approximately 80% of Ag⁺ removal).     

Removal of Malachite Green Dye from Aqueous Solution by Catalytic Wet Oxidation Technique Using Ni/Kaolin as Catalyst

In this study, natural Algerian kaolin was used as a support and impregnated with nickel at different loading amounts (2 wt.%, 5 wt.%, and 7 wt.%) in order to prepare a supported catalyst. The wet impregnation technique was used in this preparation; nickel oxide (NiO) was the active phase precursor of the catalyst, and the catalysts were designated as follows: 2%, 5%, and 7% Ni/kaolin. These catalysts were put to the test in catalytic wet peroxide oxidation (CWPO) for degrading the organic contaminant malachite green dye (MG). Analytical techniques such as FTIR spectroscopy, X-ray diffraction, BET, and X-fluorescence were used to examine the structure, morphology, and chemical composition of the support and the produced catalysts. Several parameters, including temperature, catalytic dose, metal loading, hydrogen peroxide volume, and kinetic model were systematically investigated. The combination of improved parameters resulted in a significant increase in the catalytic activity, achieving a high removal rate of MG dye of 98.87%.     

The Extracts of Polygonum cuspidatum Root and Rhizome Block the Entry of SARS-CoV-2 Wild-Type and Omicron Pseudotyped Viruses via Inhibition of the S-Protein and 3CL Protease

COVID-19, resulting from infection by the SARS-CoV-2 virus, caused a contagious pandemic. Even with the current vaccines, there is still an urgent need to develop effective pharmacological treatments against this deadly disease. Here, we show that the water and ethanol extracts of the root and rhizome of Polygonum cuspidatum (Polygoni Cuspidati Rhizoma et Radix), a common Chinese herbal medicine, blocked the entry of wild-type and the omicron variant of the SARS-CoV-2 pseudotyped virus into fibroblasts or zebrafish larvae, with IC₅₀ values ranging from 0.015 to 0.04 mg/mL. The extracts were shown to inhibit various aspects of the pseudovirus entry, including the interaction between the spike protein (S-protein) and the angiotensin-converting enzyme II (ACE2) receptor, and the 3CL protease activity. Out of the chemical compounds tested in this report, gallic acid, a phytochemical in P. cuspidatum, was shown to have a significant anti-viral effect. Therefore, this might be responsible, at least in part, for the anti-viral efficacy of the herbal extract. Together, our data suggest that the extracts of P. cuspidatum inhibit the entry of wild-type and the omicron variant of SARS-CoV-2, and so they could be considered as potent treatments against COVID-19.     

A new agent for sentinel lymph node detection: preliminary results

Sentinel lymph node detection is widely used to identify lymph nodes that receive lymphatic drainage from a primary tumor. ^99mTc labeled iron oxide nanoparticles were prepared to invent a new colorful radioactive agent for sentinel lymph node detection. Iron oxide nanoparticles were produced by co-precipitation of FeCl₃ and FeCl₂ in the presence of NaOH. Then iron oxide nanoparticles were labeled with ^99mTc. ^99mTc labeled nanoparticles (7.4 MBq/0.1 mL) were intradermally injected in the distal hind limb of 16 rabbits. Dynamic and static lymphoscintigraphic images were taken for 24 h. Labeling efficiencies of ^99mTc-iron oxide nanoparticles were over 99%. Their sizes are between 50 and 60 nm. ^99mTc-iron oxide nanoparticles were accumulated in the popliteal lymph node in 11 of 16 rabbits (69%). Retention of nanoparticles in the popliteal lymph node was obvious at from 2nd through 24th hours. The radioactive lymph node was identified easily by gamma probe. The popliteal lymph node was excised and established for radioactivity and black dye. These black and radioactive nanoparticles may be potential agent successfully used for sentinel lymph node detection.