Larch bark procyanidins (LBPCs) have not only antioxidant and antitumor properties, but also strong bacteriostatic effects. However, it is not clear about the antibacterial mechanisms of LBPC. In this work, the antibacterial effects and mechanisms of LBPC on Staphylococcus aureus were studied in the aspects of morphological structure, cell wall and membrane, essential proteins, and genetic material. The results showed that LBPC effectively inhibited bacterial growth at a minimum inhibitory concentration of 1.75 mg/ml. Bacterial morphology was significantly altered by LBPC treatment, with the cell walls and membranes being destroyed. Extracellular alkaline phosphatase content, bacterial fluid conductivity, and Na+/K+-ATPase and Ca2+-ATPase activities in the membrane system were all increased. In the energy metabolic systems, the activities of succinate dehydrogenase, malate dehydrogenase, and adenosine triphosphatase (ATPase) were all decreased, resulting in a slowdown of metabolism and bacterial growth inhibition. Changes of protein content and composition in the bacteria suggested that the protein expression system was affected. In addition, LBPC was found to bind to DNA grooves to form complexes. Thus, LBPC has a very strong inhibitory effect on S. aureus and can kill S. aureus by destroying the integrity and permeability of the cell wall and cell membrane, affecting protein synthesis, and binding to DNA.
This paper focuses on an analysis of technical requirements for the design of a permanent magnet type electric variable transmission (PM-EVT), which is a novel series-parallel hybrid electric vehicle (HEV) powertrain concept. Similar to the planetary gear train used in the Toyota Prius II, the EVT also realizes the power split function. However, it is implemented in an electromagnetic way rather than in a mechanical way, as is the case for the Prius II with a planetary gear. In this paper, a procedure to define the technical requirements of an EVT is presented. Since the Toyota Prius II is a well-known series-parallel HEV, this vehicle is chosen as a reference. The engine, the battery and other necessary components are kept as input data. A dynamic simulation was performed in order to take into account different driving cycles. Then, based on an analysis of the simulation results (torque, speed and power) the technical requirements of the PM-EVT are defined. Finally, the PMEVT machine is designed. The PM-EVT design results are presented and validated using the finite element method. Author Keywords: Electric variable transmission , Permanent magnet machine , Planetary gear , Series-parallel HEV
Theoretical analysis and experimental tests indicate that single-phase full-bridge Z-Source inverter, compared to its three-phase counterpart, suffers greatly from low-frequency output harmonic distortion due to the 2nd harmonic component of the current drawn by the inverter bridge from the DC side.
Analytic relationship between low-frequency capacitor voltage and inductor current ripple factors and ZSource network parameters of single-phase Z-Source inverter under Simple Boost Control is derived in this paper. In addition, one novel Low-frequency Harmonics EliminationPulse Width Modulation technique is presented, which could greatly reduce low-frequency capacitor voltage ripple for given Z-Source network. The theoretical analyses and proposed modified pulse width modulation technique have been confirmed by computer simulation and laboratoryimplemented prototype.
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