3results about How to "Increase positive charge" patented technology

The invention discloses a targeted antibacterial peptide SWP aiming at escherichia coli and a preparation method and application thereof, and belongs to the technical field of biology, and the amino acid sequence of the targeted antibacterial peptide SWP is shown as SEQ ID No.1. A peptide fragment SGNLTKY which is obtained by screening through a phage display peptide library and has escherichia coli affinity is used as a targeting region of the targeted antibacterial peptide, an active peptide WKKIWKPGIKKWIK is used as a functional region, the peptide fragment and the active peptide are connected to construct the novel antibacterial peptide SWP with the targeted escherichia coli, the novel antibacterial peptide SWP shows a good targeting effect, and under the condition that the influence on other bacteria is small, the antibacterial peptide SGNLTKY and the active peptide WKKIPGIKKWIK can be used for preparing the antibacterial peptide SWP with the targeted escherichia coli affinity. The compound has efficient antibacterial activity on escherichia coli. In addition, the antibacterial peptide SWP has relatively low hemolytic activity and cytotoxicity.

The application discloses a salt-resistant water-non-dispersible material for oil well cement and a preparation method thereof. The salt-resistant water-non-dispersible material for oil well cement comprises the following components in the form of weight parts: 100 parts of N,N-dimethyl acrylamide, 3-6 parts of acrylic acid, 10-20 parts of 2-acrylamide-2-methylpropanesulfonic acid, 5-15 parts of a cyclic monomer, 0.1-0.4 parts of a branching agent, 5-15 parts of a cationic monomer, 0.3-3 parts of a crosslinking agent and 400-500 parts of water. The salt-resistant water-non-dispersible material prepared by the application has good salt resistance, can significantly improve the anti-dispersion performance of the cement slurry when used in a salt water and sea water cement slurry system with a NaCl content of 18 wt% or less, and has excellent rheological performance.

The invention provides a selenium-containing wastewater treatment method, and belongs to the technical field of wastewater treatment. The treatment method comprises the following steps: adjusting the pH value of the selenium-containing wastewater to 7-10, adding an organic-inorganic composite flocculant, carrying out stirring reaction, and carrying out solid-liquid separation to obtain primarily treated wastewater; introducing the primarily treated wastewater into a tower oxidation reactor for ozone oxidation reaction to oxidize tetravalent selenium into hexavalent selenium; the wastewater subjected to ozone oxidation is adjusted to be weakly acidic and then flows through a manganese sand filter, and selenium in the wastewater is adsorbed by manganese sand; wherein in the tower-type oxidation reactor, the wastewater and ozone gas are subjected to gas-liquid countercurrent contact reaction and then subjected to standing reaction. According to the method, three-stage processes are set, including flocculation and sedimentation of an organic and inorganic composite flocculant, step-by-step oxidation of ozone, filtration and adsorption of manganese sand under weak acidity, and efficient oxidation of selenite (tetravalent selenium) into selenate (tetravalent selenium), so that the selenium removal efficiency is improved, and the removal rate of selenium in selenium-containing wastewater reaches up to 99% or above.