非洲经济特区发展及中国特区经验启示

非洲各国致力于复制和学习东亚和中国的发展模式,力图通过建立各种形式和职能的经济特区、出台各种优惠政策和提供便利服务来吸引外资、鼓励外商投资。相对而言,非洲发展出口产业和世界贸易的区位条件均较好,经济特区起步亦较早。经过多年发展,非洲经济特区总体发展形势越来越好,已拥有为数众多的出口加工区、自由港、工业园、自由贸易区以及旨在实现非洲经济一体化的各种区域一体化组织,非洲大陆自由贸易区建设亦渐趋渐进。我国一直保持与非洲国家的友好关系,随着我国经济特区发展模式的成功,对非关系逐渐开始由援助向合作转变,并通过建立中非经贸合作区,实现中国经济特区发展模式的输出,最终实现中非互赢互惠。

A role for Retinoblastoma 1 in hindbrain morphogenesis by regulating GBX family

The hindbrain,which develops from the anterior end of the neural tube expansion,can differentiate into the metencephalon and myelencephalon,with varying sizes and functions.The midbrain–hindbrain boundary(MHB)and hindbrain myelencephalon/ventral midline(HMVM)are known to be the source of the progenitors for the anterior hindbrain and myelencephalon,respectively.However,the molecular networks regulating hindbrain morphogenesis in these structures remain unclear.In this study,we show that retinoblastoma 1(rb1)is highly expressed at the MHB and HMVM in zebrafish.Knocking out rb1 in mice and zebrafish results in an enlarged hindbrain due to hindbrain neuronal hyperproliferation.Further study reveals that Rb1 controls the hindbrain morphogenesis by suppressing the expression of Gbx1/Gbx2,essential transcription factors for hindbrain development,through its binding to E2f3/Hdac1,respectively.Interestingly,we find that Gbx1 and Gbx2 are expressed in different types of hindbrain neurons,suggesting distinct roles in hindbrain morphogenesis.In summary,our study clarifies the specific role of RB1 in hindbrain neural cell proliferation and morphogenesis by regulating the E2f3–Gbx1 axis and the Hdac1–Gbx2 axis.These findings provide a research paradigm for exploring the differential proliferation of neurons in various brain regions.

Degradation of antipyrine in the Fenton-like process with a La-doped heterogeneous catalyst

The aim of this study was to synthesize a novel lanthanum(La)doped catalyst and to investigate antipyrine removal in wastewater using the Fenton-like process with the catalyst.The La-doped Co-Cu-Fe catalyst was synthesized using the modified hydrothermal method.Results showed that the Ladoped catalyst had higher specific surface area and lower particle size than the catalyst without La doping(i.e.,the control)(267 vs.163 m2/g and 14 vs.32 nm,respectively).Under the conditions of catalyst dosage 0.5 g/L,H2O2 concentration 1.70 g/L,and NaHCO3 0.1g/L,the antipyrine removal within 60 min using the Fenton-like process with the La-doped catalyst was much higher than that with the control(95%vs.54%).The hydroxyl radical concentration with the La-doped catalyst within 60 min was two times higher than that with the control(49.2 vs.22.1 gg/L).The high catalytic activity of La-doped catalyst was mainly attributed to its high specific surface area based on the X-ray photoelectron spectroscopy result.Our La-doped catalyst should have great potential to remove antipyrine in wastewater using the heterogeneous Fenton-like process.

A pulsed switching peroxi-coagulation process to control hydroxyl radical production and to enhance 2,4-Dichlorophenoxyacetic acid degradation

The aim of this study was to develop a new pulsed switching peroxi-coagulation system to control hydroxyl radical(∙OH)production and to enhance 2,4-Dichlorophenoxyacetic acid(2,4-D)degradation.The system was constructed with a sacrifice iron anode,a Pt anode,and a gas diffusion cathode.Production of H_(2)O_(2) and Fe^(2+)was controlled separately by time delayers with different pulsed switching frequencies.Under current densities of 5.0 mA/cm^(2)(H_(2)O_(2))and 0.5 mA/cm^(2)(Fe^(2+)),the∙OH production was optimized with the pulsed switching frequency of 1.0 s(H_(2)O_(2)):0.3 s(Fe^(2+))and the ratio of H_(2)O_(2) to Fe^(2+)molar concentrations of 6.6.Under the optimal condition,2,4-D with an initial concentration of 500 mg/L was completely removed in the system within 240 min.The energy consumption for the 2,4-D removal in the system was much lower than that in the electro-Fenton process(686 vs.13610 kWh/kg TOC).The iron consumption in the system was~20 times as low as that in the peroxi-coagulation process(19620 vs.3940400 mg/L)within 240 min.The system should be a promising peroxi-coagulation method for organic pollutants removal in wastewater.

Pesticide wastewater treatment using the combination of the microbial electrolysis desalination and chemical-production cell and Fenton process

The combination of the microbial electrolysis desalination and chemical-production cell(MEDCC)and Fenton process for the pesticide wastewater treatment was investigate in this study.Real wastewater with several toxic pesticides,1633 mg/L COD,and 200 in chromaticity was used for the investigation.Results showed that desalination in the desalination chamber of MEDCC reached 78%.Organics with low molecular weights in the desalination chamber could be removed from the desalination chamber,resulting in 28%and 23%of the total COD in the acid-production and cathode chambers,respectively.The desalination in the desalination chamber and organic transfer contributed to removal of pesticides(e.g.,triadimefon),which could not be removed with other methods,and of the organics with low molecular weights.The COD in the effluent of the MEDCC combined the Fenton process was much lower than that in the perixo-coagulaiton process(<150 vs.555 mg/L).The combined method consumed much less energy and acid for the pH adjustment than that the Fenton.

Using crosslinked polyvinyl alcohol polymer membrane as a separator in the microbial fuel cell

Separator between anode and cathode is an essential part of the microbial fuel cell （MFC） and its property could significantly influence the system perfor- mance. In this study we used polyvinyl alcohol （PVA） polymer membrane crosslinked with sulfosuccinic acid （SSA） as a new separator for the MFC. The highest power density of 7594-4 mW-m-2 was obtained when MFC using the PVA membrane crosslinked with 15% of SSA due to its desirable proton conductivity （5.16 x 10-2 S.cml）. The power density significantly increased to 11064- 30 mW.m-2 with a separator-electrode-assembly config- uration, which was comparable with glass fiber （11704- 46 mW.m-2）. The coulombic efficiencies of the MFCs with crosslinked PVA membranes ranged from 36.3% to 45.7% at a fix external resistance of lO00f2. The crosslinked PVA membrane could be a promising alter- native to separator materials for constructing practical MFC system.