电能细胞的合成生物学设计构建

电能细胞具有与外界环境进行双向电子交换的能力,包括向外界环境释放电子的产电细胞,以及从外界环境获取电子的噬电细胞,在微生物电化学系统中发挥微生物电催化剂的核心作用。以电能细胞为核心的微生物电化学系统在生态环境治理、绿色能源开发、化学品高效合成等方面有着广泛应用。但是野生电能细胞因其摄取底物能力弱、胞内电子通量小、双向跨膜电子传递效率低、生物膜形成能力差等原因,化学能到电能的双向转化效率受到极大限制,是实现微生物电化学系统大规模产业化应用的核心瓶颈。本综述聚焦近5年电能细胞合成生物学改造的最新研究进展,通过分析双向电子传递的分子机制,分类汇总产电细胞和噬电细胞的合成生物学改造策略:(1)工程产电细胞(强化产电细胞的胞内电子生成、胞外传递效率,具体为拓宽底物谱、增强还原力转化,提高胞外传递能力、促进电极生物膜形成);(2)工程噬电细胞(强化噬电细胞胞外电子摄取、还原力转化、产物合成效率,包括提高噬电细胞电子摄取和还原力转化,调控细胞代谢路径电合成化学品和生物燃料)。最后,展望了未来高效电能细胞和微生物电化学系统的设计与构建。

Laser processing effects on Ti−45Nb alloy surface,corrosive and biocompatible properties

The Ti−45Nb(wt.%)alloy properties were investigated in relation to its potential biomedical use.Laser surface modification was utilized to improve its performance in biological systems.As a result of the laser treatment,(Ti,Nb)O scale was formed and various morphological features appeared on the alloy surface.The electrochemical behavior of Ti−45Nb alloy in simulated body conditions was evaluated and showed that the alloy was highly resistant to corrosion deterioration regardless of additional laser surface modification treatment.Nevertheless,the improved corrosion resistance after laser treatment was evident(the corrosion current density of the alloy before laser irradiation was 2.84×10^(−8)A/cm^(2),while that after laser treatment with 5 mJ was 0.65×10^(−8)A/cm^(2))and ascribed to the rapid formation of a complex and passivating bi-modal surface oxide layer.Alloy cytotoxicity and effects of the Ti−45Nb alloy laser surface modification on the MRC-5 cell viability,morphology,and proliferation were also investigated.The Ti−45Nb alloy showed no cytotoxic effect.Moreover,cells showed improved viability and adherence to the alloy surface after the laser irradiation treatment.The highest average cell viability of 115.37%was attained for the alloy laser-irradiated with 15 mJ.Results showed that the laser surface modification can be successfully utilized to significantly improve alloy performance in a biological environment.

Reduction Bending of Thin Crystalline Silicon Solar Cells

Reported are the results of reduction the bending of thin crystalline silicon solar cells after printing and sintering of back electrode by changing the back electrode paste and adjusting the screen printing parameters without effecting the electrical properties of the cell.Theory and experiments showed that the bending of the cell is changed with its thickness of substrate,the thinner cell,the more serious bending.The bending of the cell is decreased with the thickness decrease of the back contact paste.The substrate with the thickness of 190 μm printing with sheet aluminum paste shows a relatively lower bend compared with that of the substrate printing with ordinary aluminum paste,and the minimum bend is 0.55 mm which is reduced by 52%.

Effects of Various Pulsed Electric Field Conditions on Cell Disintegration and Mass Transfer of Sugar Beet

Pulsed electric field is an innovative method for non-thermal food processing. The effects of pulsed electric field on cell disintegration and mass transfer in sugar beet were studied. Sugar beet slices were treated by various Field strengths （0.5-6 kV cm^-1）, capacity of capacitors （0.5, 8 and 32 μF） and pulse numbers （1-100 pulses）. The cell disintegration index and energy input for each treated sample was evaluated. The results showed that the cell membrane of PEF （Pulsed Electric Field） treated samples using 2 kV cm^-1, 8 μF after 20 pulses, and 3 kV cm1, 8 μF after 10 pulses were rapidly disintegrated in less than 1 min. Most important parameters during cell permeabilization were the total energy input followed by field strength. Energy efficiency index was defined as cell disintegration index per energy input unit. The maximum efficiency index was achieved using 2 kV cm^-1, 8 μF after 5 pulses. Comparison between PEF pretreatment and thermal method showed that large amount of sugar may be extracted after PEF pretreatment using field strength of 2 Kv cm^-1, 8μF in less than 10 min at ambient temperature. In.addition, the consumed energy for thermal treatment was approximately 20 to 50 times more than PEF pretreatment. Optimizing the field conditions in PEF treatment is an important factor to achieve high amount of sugar extraction from sugar beet.

Electrochemical Properties of Electrodes with Different Shapes and Diffusion Kinetic Analysis of Microbial Fuel Cells on Ocean Floor

Microbial fuel cell(MFC) on the ocean floor is a kind of novel energy-harvesting device that can be developed to drive small instruments to work continuously.The shape of electrode has a great effect on the performance of the MFC.In this paper,several shapes of electrode and cell structure were designed,and their performance in MFC were compared in pairs:Mesh(cell-1) vs.flat plate(cell-2),branch(cell-3) vs.cylinder(cell-4),and forest(cell-5) vs.disk(cell-6) FC.Our results showed that the maximum power densities were 16.50,14.20,19.30,15.00,14.64,and 9.95 mWm-2 for cell-1,2,3,4,5 and 6 respectively.And the corre-sponding diffusion-limited currents were 7.16,2.80,18.86,10.50,18.00,and 6.900 mA.The mesh and branch anodes showed higher power densities and much higher diffusion-limited currents than the flat plate and the cylinder anodes respectively due to the low diffusion hindrance with the former anodes.The forest cathode improved by 47% of the power density and by 161% of diffusion-limited current than the disk cathode due to the former's extended solid/liquid/gas three-phase boundary.These results indicated that the shape of electrode is a major parameter that determining the diffusion-limited current of an MFC,and the differences in the elec-trode shape lead to the differences in cell performance.These results would be useful for MFC structure design in practical applica-tions.

Real Time Hotspot Detection System Using Scan-Method for PV Generation System

This paper presents a real time hotspot detection system using scan-method about PV （photo voltaic） solar panel I-V characteristic based on the periodic inspection of the I-V curve of the PV panel in real time. The I-V tracking is performed by the means of periodic current sweeps during the normal operation of the panel. The current variation in a specific voltage range allows to distinguish hotspot cells from normal cells. In case if partial shadowing occurs to the PV panel, the PCS （power conditioning system） gives an immediate judgment whether hot-spot arises from one of the cells or not by applying the scan-method. The PCS is programed to calculate the current rate depending on the difference in the current divided by the short circuit current. From the experimental results, it is clarified that the hot-spot cells can be determined regardless of the solar intensity radiation.

Effect of electroacupuncture on expression of TNF-α and IL-1β in substantia nigra in rats with Parkinson's disease

Objective To observe mechanisms of electroacupuncture （EA） on treating Parkinson＇ s disease （PD）. Methods Fifty SD rats were randomly divided into 4 groups： a normal control group （Norm）, a sham operation group （Sham）, a model group （Mod） and an electroacupuncture （EA） group. EA at ＂Fengfu＂ （风府 GV16） and ＂Taichong＂ （太冲 LR 3） was applied once daily for 2 weeks in Group EA, and no treatment was given to the animals in the other three groups. PD model was established by using 6-hydroxydopamine. Numbers of tyrosine hydroxylase （TH）, tumor necrosis factor-alpha （TNF-α）and interleukin-1 beta （IL-1β） positive reactive cells in substantia nigra （SN） were counted by using immunohistochemical methods. Results The total TH positive neurons in Group Mod were obviously less than those in Group Norm and Group Sham （P〈0.01）, and the numbers of TNF-α and IL-1β positive cells in Group Mod increased more significantly than those in Group Norm, and Group Sham （P〈0.01）. The total TH positive neurons in Group EA were obviously more than those in Group Mod （P〈0.01）, and the numbers of TNF-α and IL-1β positive cells in Group EA were obviously less than those in Group Mod （P〈0.01）, indicating that EA could markedly lower the contents of such pre-inflammatory factors like TNF-α and IL-1β in SN of experimental rats with PD. Conclusion EA may provide its protective functions on dopaminergic neurons by way of alleviating inflammatory reactions in SN of rats with PD.

Microbial Reduction of Graphene Oxide by Shewanella

Graphene oxide （GO） can be reduced to graphene in a normal aerobic setup under ambient conditions as mediated by microbial respiration of Shewanella cells. The microbially-reduced graphene （MRG） exhibited excellent electrochemical properties. Extracellular electron transfer pathways at the cell/GO interface were systematically investigated, suggesting both direct electron transfer and electron mediators are involved in the GO reduction.

Targeted inductive heating of nanomagnets by a com- bination of alternating current （AC） and static magnetic fields

The conversion of electromagnetic energy into heat by nanomagnets has the potential to be a powerful, non-invasive technique for cancer therapy by hyperthermia and hyperthermia-based drug release, while temperature controllability and targeted heating are challenges to developing applications of such magnetic inductive hyperthermia. This study was designed to control the hyperthermia position and area using a combination of alternating current （AC） and a static magnetic field. MnZn ferrite （MZF） nanoparticles which exhibited excellent hyperthermia properties were first prepared and characterized as an inductive heating mediator. We built model static magnetic fields simply using a pair of permanent magnets and studied the static magnetic field distributions by measurements and numerical simulations. The influence of the transverse static magnetic fields on hyperthermia properties was then investigated on MZF magnetic fluid, gel phantoms and SMMC-7721 cells in vitro. The results showed a static magnetic field can inhibit the temperature rise of MZF nanoparticles in an AC magnetic field. But in the uneven static magnetic field formed by a magnet pair with repelling poles face-to-face, the heating area can be restricted in a central low static field; meanwhile the side effects of hyperthermia can be reduced by a surrounding high static field. As a result we can position the hyperthermia area, protect the non-therapeutic area, and reduce the side effects lust by using a well-designed combination of AC and static field.

Effect of Exposing Low-Frequency Electric Fields on the Proliferative Capacity and Morphological Features of Olfactory Ensheathing Cells in vitro

Olfactory ensheathing cells(OECs) transplanted into the damaged spinal cord may be considered as a valuable remedy explorations for spinal cord repair. The proliferation of transplanted olfactory ensheathing cells depends on various environmental factors and effective cues, which may include electrical fields(EFs). In this study, we investigated the proliferative capacity, morphologic alterations of olfactory ensheathing cells derived from neonate rat that occurd when exposed to two EFs of 20 Hz, 50 mV and20 Hz, 100 mV for 6 h. For both EF treatments, the MTT results revealed that the cellular proliferation of exposed group during the last 6 h of the experiment was statistically higher than that of control group. Then, we investigated morphological structure changes in the cells stained by Coomassie brilliant blue. Compared with control group, most of cells were present at intensively proliferating appearance including the microfilaments were long and thick and the accumulated appearance of cells. It is conceivable that electrical fields as a new approach may promote the growth and proliferation of OECs and may be engineered to control the survival of transplanted OECs in injured spinal cord.Although our results have been suggesting that EFs may be non-chemical strategies for cell proliferation, the fundamental mechanisms remain to be elucidated.