Functional study of Treponema pallidum genes using Borrelia burgdorferi as a surrogate system / 中华微生物学和免疫学杂志

Objective To employ Borrelia burgdorferi( B. burgdorferi) , a culturable and genetical-ly transformable spirochete, as a surrogate system to study Treponema pallidum ( T. pallidum) gene function. Methods Bioinformatic analysis revealed that the T. pallidum gene tp0111 encodes the putative sigma factor RpoN. We constructed a B. burgdorferi shuttle vector harboring tp0111. The shuttle vector was then trans-formed into the B. burgdorferi rpoN mutant strain. The phenotype of the resulting B. burgdorferi strain was then determined. Results We successfully constructed the B. burgdorferi rpoN mutant carrying the T. palli-dum gene tp0111. We found that tp0111 could partially complement the B. burgdorferi rpoN mutant. Con-clusion This work provides the first experimental evidence showing that tp0111 is the rpoN gene of T. palli-dum. It also demonstrates that B. burgdorferi can be used as a surrogate system for studying T. pallidum gene function.

Modeling and analysis of volume conduction based on field-circuit coupling / 生物医学工程学杂志

Numerical simulations of volume conduction can be used to analyze the process of energy transfer and explore the effects of some physical factors on energy transfer efficiency. We analyzed the 3D quasi-static electric field by the finite element method, and developed A 3D coupled field-circuit model of volume conduction basing on the coupling between the circuit and the electric field. The model includes a circuit simulation of the volume conduction to provide direct theoretical guidance for energy transfer optimization design. A field-circuit coupling model with circular cylinder electrodes was established on the platform of the software FEM3.5. Based on this, the effects of electrode cross section area, electrode distance and circuit parameters on the performance of volume conduction system were obtained, which provided a basis for optimized design of energy transfer efficiency.

A novel voltage multiplier for X-ray power supply / 生物医学工程学杂志

In this paper, a seriesly connected three phase bipolar symmetrical voltage multiplier (VM) is proposed, which is a novel VM for X-ray power supply. It consists of three single phase bipolar symmetrical VM, which are connected in series at their smoothing columns. The charging and discharging process occurs six times in a cycle and the frequency of the output voltage ripple is six times as large as the drive signal frequency. The proposed VM has three times larger output voltage and three times smaller ripple factor as compared to single phase bipolar symmetrical VM, and smaller voltage drop and faster dynamic response than those of the series connected three phase symmetrical VM. The simulation is provided to show the feasibility of proposed VM.

Mini-thoracotomy focus cleaning for cavitary pulmonary tuberculosis or pulmonary tuberculoma: A report of 18 cases / 中国微创外科杂志

Objective To investigate the effects and feasibility of mini-thoracotomy focus cleaning in the management of cavitary pulmonary tuberculosis or pulmonary tuberculoma. Methods The mini-thoracotomy approach was adopted in patients with cavitary pulmonary tuberculosis or pulmonary tuberculoma who had undergone long-term anti-tuberculosis therapy or needed a re-treatment.Eight patients with chronic fibro-cavitative pulmonary tuberculosis and 10 patients with pulmonary tuberculoma underwent focus cleaning, irrigation, and folding suture. Results All the 18 patients were cured clinically, with their sputum findings turning negative for bacteria and pulmonary shadows subsiding. No operative complications occurred. Follow-up for 1～4 years found no recurrence. Conclusions Focus cleaning is an effective surgical alternative for pulmonary tuberculosis after proper selection of cases. The procedure is minimally invasive and patient's pulmonary function can be protected to the greatest possible advantage.