Understanding the steady mechanism of biomass smoldering plays a great role in the utilization of smoldering technology.In this study numerical analysis of steady smoldering of biomass rods was performed.A two-dimensi...Understanding the steady mechanism of biomass smoldering plays a great role in the utilization of smoldering technology.In this study numerical analysis of steady smoldering of biomass rods was performed.A two-dimensional(2D)steady model taking into account both char oxidation and pyrolysis was developed on the basis of a calculated propagation velocity according to empirical correlation.The model was validated against the smoldering experiment of biomass rods under natural conditions,and the maximum error was smaller than 31%.Parameter sensitivity analysis found that propagation velocity decreases significantly while oxidation area and pyrolysis zone increase significantly with the increasing diameter of rod fuel.展开更多
Five rice ( Oryza sativa L.) cultivars, widely planted in South China, were grown in greenhouse with or without supplemental UV_B radiation at level of 13.6 kJ·m -2 ·d -1 . After 15 day_UV_B treat...Five rice ( Oryza sativa L.) cultivars, widely planted in South China, were grown in greenhouse with or without supplemental UV_B radiation at level of 13.6 kJ·m -2 ·d -1 . After 15 day_UV_B treatment, significant intraspecific differences were observed in plant height, photosynthetic rate and total biomass. Based on the total biomass accumulation, cultivar “Tesanai” was found to be the most sensitive, and cultivar “Luhuangzhan” was the most tolerant species to UV_B radiation. UV_B induced cyclobutane pyrimidine dimer (CPD) in rice DNA were quantified by ELISA with specific monoclonal antibody. CPD accumulations in DNA extracted from 5 rice cultivars were remarkably increased by UV_B radiation, and it was confirmed that there was a strong positive correlation between CPD accumulation and the inhibition of total biomass. Photorepair was proved to be the predominant mode of CPD repair in UV_B irradiated rice. Light_dependent removal of CPD was very fast as compared with dark repair. Different levels of CPD accumulation among rice cultivars were related with different capacity of CPD photorepair. Capacity of light_dependent CPD removal may play an important role in UV_B resistance of rice.展开更多
[Objective] To predict the secondary structure and B cell epitopes of the rice major allergen RAG1. [Method] The amino acid sequence of rice allergen RAG1 was acquired from Expasy protein database. The secondary struc...[Objective] To predict the secondary structure and B cell epitopes of the rice major allergen RAG1. [Method] The amino acid sequence of rice allergen RAG1 was acquired from Expasy protein database. The secondary structure of RAG1 was predicted by DNAStar Protean software with Gamier-Robson program, Chou-Fasman program and Karplus-Schulz program; the B cell epitopes of RAG1 was predicted with the Kyte Doolittle hydrophilic program, Emini surface accessibility program and Jameson-Wolf antigenic index program. [Result] The predictions on secondary structure and B cell epitopes showed that the regions of 33-44, 119-129, 155-163 were the dominant B cell epitopes. [Conclusion] This study predicted the potential dominant B cell epitopes in rice allergen RAG1 by comprehensive use of multi-methods and multi-parameters, and provided a theoretical basis for further researches on identification, antigen modification and epitope vaccine design of RAG1 B cell epitopes.展开更多
Two organic dyes XSS1 and XS52 derivated from triarylamine and indoline are synthesized for dye-sensitized solar ceils (DSCs) employing cobalt and iodine redox shuttles. The effects of dye structure upon the photoph...Two organic dyes XSS1 and XS52 derivated from triarylamine and indoline are synthesized for dye-sensitized solar ceils (DSCs) employing cobalt and iodine redox shuttles. The effects of dye structure upon the photophysical, electro-chemical characteristics and cell perfor- mance are investigated. XS51 with four hexyloxyl groups on triarylamine performs better steric hindrance and an improvement of photovoltage. X852 provides higher short-circuit photocurrent density due to the strong electron-donating capability of indoline unit. The results from the redox electrolyte on cell performances indicate that the synthesized dyes are more suitable for tris(1,10-phenanthroline)cobalt(II/III) redox couple than I-/I3- redox couple in assembling DSCs. Application of X852 in the cobalt electrolyte yields a DSC with an overall power conversion efficiency of 6.58% under AM 1.5 (100 mW/cm2) irradiation.展开更多
It is desirable to develop highly efficient and sustainable catalytic systems for CO_(2) photoreduction using efficient heterogeneous photosensitizers(PSs);however,this remains a great challenge.In this study,we doped...It is desirable to develop highly efficient and sustainable catalytic systems for CO_(2) photoreduction using efficient heterogeneous photosensitizers(PSs);however,this remains a great challenge.In this study,we doped[Ru(bpy)3]^(2+) into UiO-metal-organic frameworks(MOFs)to facilitate the separation and reuse of noble metal PS.By simply adjusting the loading amount,a series of heterogeneous photoactive MOFs,namely,UiO-Ru-1,UiO-Ru-2,and UiO-Ru-3,were constructed to act as heterogeneous PSs to drive the efficient CO_(2) photoreduction under visible-light irradiation.Remarkably,UiO-Ru-2 exhibited the best photosensitizing ability among the prepared MOFs in sensitizing the iron quarterpyridine catalyst(C-l),and the CO yield reached as high as 171 mmol/g with ca.100%selectivity,which is a record value among all the MOF-based photocatalysts.This photoactive MOF can be recycled and reused three times without any obvious activity loss,signifying its good photochemical stability.Experimental investigations confirmed that the strong visible absorption,long-lived excited state,appropriate redox potential,good photocatalytic stability,and excellent collaboration with C-l were attributable to the superior catalytic activity.This work highlights an avenue for constructing heterogeneous PSs with excellent recyclability using MOF as the platform for efficient CO_(2) reduction.展开更多
We investigated the influence of soaking time on the semi-conductivity and nonlinear electrical properties of TiO2- based varistor ceramic samples. We used a single sintering process and fabricated six disk samples of...We investigated the influence of soaking time on the semi-conductivity and nonlinear electrical properties of TiO2- based varistor ceramic samples. We used a single sintering process and fabricated six disk samples of (Sr, Bi, Si, Ta)-doped TiO2- based varistor ceramics sintered at 1 250℃ for 0.5 h, 1.0 h, 2.0 h, 3.0 h, 4.0 h, and 5.0 h, respectively. The samples were characterized by X-ray diffraction, breakdown voltage, and complex impedance. The results show that as the soaking time increases from 0.5 h to 5.0 h, the breakdown voltage drops before rising while the nonlinear coefficient increases and then decreases. We suggest that, considering both grain semi-conductivity and nonlinear electrical properties of the TiO2-based varistor ceramics, the optimal soaking time is between 2.0 h and 3.0 h.展开更多
Objective: To study whether the small-interference RNA (siRNA) targeting against Bcl-2 gene can enhance sensi-tivity of HL-60 cell to arsenic trioxide. Methods: SiRNA was transferred into the HL-60 cells. At 6 h after...Objective: To study whether the small-interference RNA (siRNA) targeting against Bcl-2 gene can enhance sensi-tivity of HL-60 cell to arsenic trioxide. Methods: SiRNA was transferred into the HL-60 cells. At 6 h after transfection, the cells were cultured with arsenic trioxide. The cell growth of the HL-60 cells was detected using MTT at 24, 48 and 72 h, respectively. The levels of the Bcl-2 protein and reactive oxygen species (ROS), as well as of the membrane potential of the mitochondrion were determined by flow cytometry. Results: The Bcl-2 siRNA significantly increased the inhibitory action of arsenic trioxide on growth of HL-60 cells. The combination of siRNA with arsenic trioxide resulted in decrease of the Bcl-2 protein level and increase of the ROS level, as well as significant descending of the membrane potential of mitochondrion of HL-60 (P < 0.05). Conclusion: The siRNA targeting Bcl-2 can increase the sensitivity of the HL-60 leukemia cells to arsenic trioxide by inhibiting the expression of Bcl-2 protein.展开更多
A high-bandwidth, high-sensitivity fully differential optoelectronic integrated receiver is implemented in a chartered 3.3 V standard 0.35μm analbg CMOS process. To convert the incident light into a pair of fully dif...A high-bandwidth, high-sensitivity fully differential optoelectronic integrated receiver is implemented in a chartered 3.3 V standard 0.35μm analbg CMOS process. To convert the incident light into a pair of fully differential photo-currents, a novel fully differential photodetector is proposed, which is composed of two completely identical photodiodes. The mea- surement results show that the receiver achieves a 1.11 GHz 3 dB bandwidth and a -13 dBm sensitivity for a 10-12 bit error at 1.5 Gb/s data rate under illumination by 850 nm incident lights.展开更多
An accurate photodiode circuit macro-model is proposed for SPICE simulation. The definition and implementation of the macro-model is based on carrier stationary continuity equation. In this macro-model, the photodiode...An accurate photodiode circuit macro-model is proposed for SPICE simulation. The definition and implementation of the macro-model is based on carrier stationary continuity equation. In this macro-model, the photodiode is a device of three pins, one for light intensity input and the other two for photocurrent output, which represent the relationship between photocurrent and incident light. The validity of the proposed macro-model is demonstrated with its PSPICE simulation result compared with reported experimental data.展开更多
This paper describes the development of a timer based voltage to frequency converter(V FC).Timer LM555is used in astable multivibrator mode with two OPTO-LDRs(light dependent resistors)in the circuitry.The frequency o...This paper describes the development of a timer based voltage to frequency converter(V FC).Timer LM555is used in astable multivibrator mode with two OPTO-LDRs(light dependent resistors)in the circuitry.The frequency of timer output waveform which is measured using a digital storage oscillator(DSO)is almost linearly proportional to the applied input voltage.Hence we obtain a linear relationship between the frequency of timer output waveform and the input voltage.Because of its quasi-digital output,the main advantages of this developed converter are linear input-output relationship,small size,easy portabilityand high cost performance.In addition,the timer output waveform can be directly interfaced with personal computer or microprocessor/microcontroller for further processing of the input voltage signal without intervening any analog-to-digital converter(ADC).展开更多
A method for determination of lycopene concentration in dog plasma wasestablished. Methods RP-HPLC was used; the mobile phase consisted of methanol-acetonitrile-methylenechloride (40:30:30, V/V) , the wavelength of de...A method for determination of lycopene concentration in dog plasma wasestablished. Methods RP-HPLC was used; the mobile phase consisted of methanol-acetonitrile-methylenechloride (40:30:30, V/V) , the wavelength of detection was 472 nm, the column temperature wasambient temperature, and the flow rate was 1.0 mL·min^(-1). Results The standard curve was linearin the range from 0.012 4 to 0.496 μg·mL^(-1) with r=0.9992. The average extraction recovery was97.6% +-4.2%. The intra-day and inter-day RSD were 1.52% -4.95% and 2.31% -7.38%, respectively.Conclusion This method is sensitive, rapid, reproducible, and of good selectivity for the analysisof lycopene in dog plasma.展开更多
A new method based on UV photosensitivity is proposed to fabricate big scale two dimensional photonic crystal.The optical transmission properties of designed periodic structure are investigated by numerical analysis.T...A new method based on UV photosensitivity is proposed to fabricate big scale two dimensional photonic crystal.The optical transmission properties of designed periodic structure are investigated by numerical analysis.The results show that the 2D photonic crystal fabricated by the new method has a desirable photonic bandgap of TE mode.展开更多
The silicon PN junction photodiode with very small sensitive area has been investigated.The device gets superhigh light current density J LS counted by the sensitive area in the planar PN junction.The superhi...The silicon PN junction photodiode with very small sensitive area has been investigated.The device gets superhigh light current density J LS counted by the sensitive area in the planar PN junction.The superhigh light current density is due to the light current transferred by the photogenerated minority carriers in the area around edges of the dopant diffused region.Then,we can determine the diffusion length of the photogenerated minority carriers in the substance by measuring the light current of the PN junction photodiode with very small sensitive area.展开更多
The role of oxygen and the generation of active radicals in the photocatalitic degradation of phenol were investigated using the eosin sensitized TiO2 as photocatalyst under visible light irradiation. Diffuse reflecta...The role of oxygen and the generation of active radicals in the photocatalitic degradation of phenol were investigated using the eosin sensitized TiO2 as photocatalyst under visible light irradiation. Diffuse reflectance spectra show that the absorbancy range of eosin/TiO2 is expanded from 378 nm (TiO2 ) to about 600 nm. The photocatalitic degradation of phenol is almost stopped when the eosin/TiO2 system is saturated with N2 , which indicates the significance of O2 . The addition of NaN 3 (a quencher of single oxygen) causes about a 62% decrease in the phenol degradation. The phenol degradation ratio is dropped from 92% to 75% when the isopropanol (a quencher of hydroxyl radical) is present in the system. The experimental results show that there are singlet oxygen and hydroxyl radical generated in the eosin/TiO2 system under visible light irradiation. The changes of absorbancy indicate that the hydrogen peroxide might be produced. Through the analysis and comparison, it is found that the singlet oxygen is the predominant active radical for the degradation of phenol.展开更多
Objective To reduce the toxicity and side effects of arsenic trioxide(ATO)and provide a new approach for the treatment of primary liver cancer,a folic acid-modified calcium arsenite liposomal“target-controlled”drug ...Objective To reduce the toxicity and side effects of arsenic trioxide(ATO)and provide a new approach for the treatment of primary liver cancer,a folic acid-modified calcium arsenite liposomal“target-controlled”drug delivery system(FA-LP-CaAs)was fabricated using the reverse microemulsion method.Methods A Malvern particle size analyzer and a transmission electron microscope were employed to determine the particle size,distribution,zeta potential and morphology of FA-LP-CaAs.Further,inductively coupled plasma emission spectrometry was employed to determine the drug loading capacity,entrapment efficiency,and in vitro release behavior of FA-LP-CaAs.To determine its toxicity in human hepatoma cells(HepG2)and human normal hepatocytes(LO2)and its effect on HepG2 cell cycle and apoptosis,the MTT method was used.Laser confocal and flow cytometry were also employed to determine the uptake of FA-LP-CaAs by cells.After establishing a mouse liver cancer model,the in vivo distribution of the drug included in the formulation was investigated using in vivo fluorescence.To evaluate the liver cancer targeting and anti-tumor effects of FALP-CaAs in vivo,the distribution of ATO in tissues and changes in tumor volume and body weight after liposomal administration were investigated using hematoxylin-eosin(HE)-stained tumor sections.Results The particle size,zeta potential and PDI of FA-LP-CaAs were(122.67±2.18)nm,(12.81±0.75)mV and 0.22±0.01,respectively,while its drug loading capacity was 18.49%±1.14%.In vitro experimental results revealed that FA-LP-CaAs had a strong killing effect on HepG2 cells.Further,the cell uptake capacity of this formulation was found to improve.Based on in vivo assessments,FA-LP-CaAs could significantly increase the distribution of ATO in tumor sites and inhibit tumor growth.Conclusions Herein,an FA-LP-CaAs formulation was successfully fabricated.This liposomal drug delivery system had a round appearance,uniform particle size,good polydispersity coefficient,evident“core-shell”structure,high drug loading capacity and pH response,tumor targeted drug delivery and sustained drug release.These findings support further research and the application of ATO as an anti-liver cancer prodrug and provide a new method for the treatment of liver cancer.展开更多
The influence of soaking time on the nonlinear electrical behavior and dielectric properties of TiO2-based varistor ceramics was investigated. Based on single sintering process, six disk samples of (Sr, Bi, Si, Ta)-...The influence of soaking time on the nonlinear electrical behavior and dielectric properties of TiO2-based varistor ceramics was investigated. Based on single sintering process, six disk samples of (Sr, Bi, Si, Ta)-doped TiO2-based varistor ceramics were fabricated by sintering at 1 250 ℃ for 0.5-5.0 h. The samples were characterized by X-ray diffraction, voltage-current characteristics, energy spectra, metallographs, breakdown voltages, and apparent dielectric constant. It is found that the breakdown electrical field intensity at a current density of 10 mA/cma decreases from 5.5 to 4.1 V/mm first and then increases to 7.0 V/mm, the nonlinear coefficient increases from 2.39 to 2.62 first and then decreases to 2.42, and the apparent dielectric constant increases from 98 200 to 1l5 049 first and then decreases to 73 865 with the soaking time increasing from 0.5 to 5.0 h. These indicate that the optimal soaking time is 2.0-3.0 h considering both nonlinear electrical behavior and dielectric properties.展开更多
Objective: The aim of our study was to investigate the effect of diallyl trisulfide (DATS) combining radiation on DNA injury-repair of Esophageal cancer EC109 cells. Methods: Using 10 and 20 μg/mL DATS on EC109 cells...Objective: The aim of our study was to investigate the effect of diallyl trisulfide (DATS) combining radiation on DNA injury-repair of Esophageal cancer EC109 cells. Methods: Using 10 and 20 μg/mL DATS on EC109 cells, and taking X-ray radiation 24 h later. Investigate the radiosensitization effect of DATS on EC109 cells by clone formation, and the mechanism of DNA injury-repair by Comet Assay. Results: The clone formation resulted that DATS had radiosensitization effect on EC109 cells. Radiosensitization enhancement ratios of 10 and 20 μg/mL DATS in combination with radiation were 1.55, 1.64 (Do) and 1.43, 1.75 (Dq) respectively. In the comet assay, the TM (tail moments) of 20 μg/mL DATS combining radiation group lines at 0 h, 2 h, 6 h and 24 h were 7.16 ± 2.61, 3.65 ± 2.06, 2.09 ± 0.83, 1.45 ± 1.37 respectively. They were slightly increased than radiation group (0.95 ± 0.65, 0.11 ± 0.07, 0.1 ± 0.05, 0.11 ± 0.08) and DATS group (1.81 ± 1.23, 1.58 ± 1.40, 0.45 ± 0.25, 0.60 ± 0.40) (P < 0.01). The result showed that DATS combining radiation had the effect of increasing DNA damage and inhibiting DNA repair on EC109 cells. Conclusion: DATS has radiosensitization effect on Esophageal cancer EC109 cells. And the effect is probably related with DNA injury-repair.展开更多
Phenol composition of two carnation (Dianthus caryophyllus) cvs "Gloriana" and "Roland", partially and highly resistant to F. oxysporum f. sp. dianthi, respectively, has been investigated with the aim of assessi...Phenol composition of two carnation (Dianthus caryophyllus) cvs "Gloriana" and "Roland", partially and highly resistant to F. oxysporum f. sp. dianthi, respectively, has been investigated with the aim of assessing the possible role of phenolic constituents both as biochemical markers of resistance and antifungal molecules. Analyses were performed through chromatography, NMR and MS methods. The results indicate that protocatechuic and vanillic acids are present in healthy and infected tissues of both cvs; the flavonol glycoside peltatoside. 2,6-Dimethoxybenzoic acid was detected in small amounts only in infected "Gloriana" cv while the highly resistant "Roland" cv contained the flavone datiscetin. This latter compound, due to its noticeable antifungal activity evidenced in in vitro trials, could be conceived both as a biochemical marker of resistance towards this pathogen and as a phytoanticipin.展开更多
Due to important consideration of protection against lightning surge on electrical, electronic and telecommunication equipment, it was necessary to carry out a special study to look at the performance of protective de...Due to important consideration of protection against lightning surge on electrical, electronic and telecommunication equipment, it was necessary to carry out a special study to look at the performance of protective devices. The study was testing performance of arresters on low voltage system. The activity was testing of arresters using steady state and impulse voltages. The arresters consisted of gas tube, zener diode, varistor and spark gap arresters, then it was made a cascade circuit between the varistor and spark gap arresters with a decoupling element. The decoupling elements were used air, iron and ferrite. The test yielded data of current and voltage on the tables and oscilloscope waveforms. The arresters had cut voltages early different from each other, namely the gas tube, zener diode, spark gap and varistor arresters were at the voltages of 500 V, 250 V, 1,000 V and 565 V respectively. The iron core decoupling element cascade circuit had the least oscillation among remaining cores.展开更多
文摘Understanding the steady mechanism of biomass smoldering plays a great role in the utilization of smoldering technology.In this study numerical analysis of steady smoldering of biomass rods was performed.A two-dimensional(2D)steady model taking into account both char oxidation and pyrolysis was developed on the basis of a calculated propagation velocity according to empirical correlation.The model was validated against the smoldering experiment of biomass rods under natural conditions,and the maximum error was smaller than 31%.Parameter sensitivity analysis found that propagation velocity decreases significantly while oxidation area and pyrolysis zone increase significantly with the increasing diameter of rod fuel.
文摘Five rice ( Oryza sativa L.) cultivars, widely planted in South China, were grown in greenhouse with or without supplemental UV_B radiation at level of 13.6 kJ·m -2 ·d -1 . After 15 day_UV_B treatment, significant intraspecific differences were observed in plant height, photosynthetic rate and total biomass. Based on the total biomass accumulation, cultivar “Tesanai” was found to be the most sensitive, and cultivar “Luhuangzhan” was the most tolerant species to UV_B radiation. UV_B induced cyclobutane pyrimidine dimer (CPD) in rice DNA were quantified by ELISA with specific monoclonal antibody. CPD accumulations in DNA extracted from 5 rice cultivars were remarkably increased by UV_B radiation, and it was confirmed that there was a strong positive correlation between CPD accumulation and the inhibition of total biomass. Photorepair was proved to be the predominant mode of CPD repair in UV_B irradiated rice. Light_dependent removal of CPD was very fast as compared with dark repair. Different levels of CPD accumulation among rice cultivars were related with different capacity of CPD photorepair. Capacity of light_dependent CPD removal may play an important role in UV_B resistance of rice.
基金Supported by the National Natural Science Foundation of China(30771240)the Academic Team for Scientific Research Innovation of Guangzhou Education System(B94118)~~
文摘[Objective] To predict the secondary structure and B cell epitopes of the rice major allergen RAG1. [Method] The amino acid sequence of rice allergen RAG1 was acquired from Expasy protein database. The secondary structure of RAG1 was predicted by DNAStar Protean software with Gamier-Robson program, Chou-Fasman program and Karplus-Schulz program; the B cell epitopes of RAG1 was predicted with the Kyte Doolittle hydrophilic program, Emini surface accessibility program and Jameson-Wolf antigenic index program. [Result] The predictions on secondary structure and B cell epitopes showed that the regions of 33-44, 119-129, 155-163 were the dominant B cell epitopes. [Conclusion] This study predicted the potential dominant B cell epitopes in rice allergen RAG1 by comprehensive use of multi-methods and multi-parameters, and provided a theoretical basis for further researches on identification, antigen modification and epitope vaccine design of RAG1 B cell epitopes.
文摘Two organic dyes XSS1 and XS52 derivated from triarylamine and indoline are synthesized for dye-sensitized solar ceils (DSCs) employing cobalt and iodine redox shuttles. The effects of dye structure upon the photophysical, electro-chemical characteristics and cell perfor- mance are investigated. XS51 with four hexyloxyl groups on triarylamine performs better steric hindrance and an improvement of photovoltage. X852 provides higher short-circuit photocurrent density due to the strong electron-donating capability of indoline unit. The results from the redox electrolyte on cell performances indicate that the synthesized dyes are more suitable for tris(1,10-phenanthroline)cobalt(II/III) redox couple than I-/I3- redox couple in assembling DSCs. Application of X852 in the cobalt electrolyte yields a DSC with an overall power conversion efficiency of 6.58% under AM 1.5 (100 mW/cm2) irradiation.
文摘It is desirable to develop highly efficient and sustainable catalytic systems for CO_(2) photoreduction using efficient heterogeneous photosensitizers(PSs);however,this remains a great challenge.In this study,we doped[Ru(bpy)3]^(2+) into UiO-metal-organic frameworks(MOFs)to facilitate the separation and reuse of noble metal PS.By simply adjusting the loading amount,a series of heterogeneous photoactive MOFs,namely,UiO-Ru-1,UiO-Ru-2,and UiO-Ru-3,were constructed to act as heterogeneous PSs to drive the efficient CO_(2) photoreduction under visible-light irradiation.Remarkably,UiO-Ru-2 exhibited the best photosensitizing ability among the prepared MOFs in sensitizing the iron quarterpyridine catalyst(C-l),and the CO yield reached as high as 171 mmol/g with ca.100%selectivity,which is a record value among all the MOF-based photocatalysts.This photoactive MOF can be recycled and reused three times without any obvious activity loss,signifying its good photochemical stability.Experimental investigations confirmed that the strong visible absorption,long-lived excited state,appropriate redox potential,good photocatalytic stability,and excellent collaboration with C-l were attributable to the superior catalytic activity.This work highlights an avenue for constructing heterogeneous PSs with excellent recyclability using MOF as the platform for efficient CO_(2) reduction.
基金Funded by the Natural Science Foundation of China (No. 50872001 and No. 50642038)the Scientific Research Foundation of Education Ministry of Anhui Province (No. 2005KJ224 and No. KJ2007B132)the Graduate Student Innovation Programs of Anhui University (No. 20072006)
文摘We investigated the influence of soaking time on the semi-conductivity and nonlinear electrical properties of TiO2- based varistor ceramic samples. We used a single sintering process and fabricated six disk samples of (Sr, Bi, Si, Ta)-doped TiO2- based varistor ceramics sintered at 1 250℃ for 0.5 h, 1.0 h, 2.0 h, 3.0 h, 4.0 h, and 5.0 h, respectively. The samples were characterized by X-ray diffraction, breakdown voltage, and complex impedance. The results show that as the soaking time increases from 0.5 h to 5.0 h, the breakdown voltage drops before rising while the nonlinear coefficient increases and then decreases. We suggest that, considering both grain semi-conductivity and nonlinear electrical properties of the TiO2-based varistor ceramics, the optimal soaking time is between 2.0 h and 3.0 h.
基金Supported by the key Subject Foundation of Overseas Chinese Affairs Office of the State Council (No. 2005).
文摘Objective: To study whether the small-interference RNA (siRNA) targeting against Bcl-2 gene can enhance sensi-tivity of HL-60 cell to arsenic trioxide. Methods: SiRNA was transferred into the HL-60 cells. At 6 h after transfection, the cells were cultured with arsenic trioxide. The cell growth of the HL-60 cells was detected using MTT at 24, 48 and 72 h, respectively. The levels of the Bcl-2 protein and reactive oxygen species (ROS), as well as of the membrane potential of the mitochondrion were determined by flow cytometry. Results: The Bcl-2 siRNA significantly increased the inhibitory action of arsenic trioxide on growth of HL-60 cells. The combination of siRNA with arsenic trioxide resulted in decrease of the Bcl-2 protein level and increase of the ROS level, as well as significant descending of the membrane potential of mitochondrion of HL-60 (P < 0.05). Conclusion: The siRNA targeting Bcl-2 can increase the sensitivity of the HL-60 leukemia cells to arsenic trioxide by inhibiting the expression of Bcl-2 protein.
基金the National Natural Science Foundation of China (grant numbers:60536030 and 60676038)the Tianjin Natural Science Foundation (No.06YFJZJC00200)
文摘A high-bandwidth, high-sensitivity fully differential optoelectronic integrated receiver is implemented in a chartered 3.3 V standard 0.35μm analbg CMOS process. To convert the incident light into a pair of fully differential photo-currents, a novel fully differential photodetector is proposed, which is composed of two completely identical photodiodes. The mea- surement results show that the receiver achieves a 1.11 GHz 3 dB bandwidth and a -13 dBm sensitivity for a 10-12 bit error at 1.5 Gb/s data rate under illumination by 850 nm incident lights.
基金National Natural Science Foundation of China(30470469)
文摘An accurate photodiode circuit macro-model is proposed for SPICE simulation. The definition and implementation of the macro-model is based on carrier stationary continuity equation. In this macro-model, the photodiode is a device of three pins, one for light intensity input and the other two for photocurrent output, which represent the relationship between photocurrent and incident light. The validity of the proposed macro-model is demonstrated with its PSPICE simulation result compared with reported experimental data.
文摘This paper describes the development of a timer based voltage to frequency converter(V FC).Timer LM555is used in astable multivibrator mode with two OPTO-LDRs(light dependent resistors)in the circuitry.The frequency of timer output waveform which is measured using a digital storage oscillator(DSO)is almost linearly proportional to the applied input voltage.Hence we obtain a linear relationship between the frequency of timer output waveform and the input voltage.Because of its quasi-digital output,the main advantages of this developed converter are linear input-output relationship,small size,easy portabilityand high cost performance.In addition,the timer output waveform can be directly interfaced with personal computer or microprocessor/microcontroller for further processing of the input voltage signal without intervening any analog-to-digital converter(ADC).
文摘A method for determination of lycopene concentration in dog plasma wasestablished. Methods RP-HPLC was used; the mobile phase consisted of methanol-acetonitrile-methylenechloride (40:30:30, V/V) , the wavelength of detection was 472 nm, the column temperature wasambient temperature, and the flow rate was 1.0 mL·min^(-1). Results The standard curve was linearin the range from 0.012 4 to 0.496 μg·mL^(-1) with r=0.9992. The average extraction recovery was97.6% +-4.2%. The intra-day and inter-day RSD were 1.52% -4.95% and 2.31% -7.38%, respectively.Conclusion This method is sensitive, rapid, reproducible, and of good selectivity for the analysisof lycopene in dog plasma.
文摘A new method based on UV photosensitivity is proposed to fabricate big scale two dimensional photonic crystal.The optical transmission properties of designed periodic structure are investigated by numerical analysis.The results show that the 2D photonic crystal fabricated by the new method has a desirable photonic bandgap of TE mode.
文摘The silicon PN junction photodiode with very small sensitive area has been investigated.The device gets superhigh light current density J LS counted by the sensitive area in the planar PN junction.The superhigh light current density is due to the light current transferred by the photogenerated minority carriers in the area around edges of the dopant diffused region.Then,we can determine the diffusion length of the photogenerated minority carriers in the substance by measuring the light current of the PN junction photodiode with very small sensitive area.
基金Project(8451063201001261) supported by the Guangdong Natural Science Fund Committee,ChinaProject(LYM08022) supported by the Foundation for Distinguished Young Talents in Higher Education of Guangdong,China+1 种基金Project (2007A032400001, 2008A030202010) supported by the Scientific and Technological Planning of Guangdong Province,ChinaProject(216113132) supported by the Scientific Research Cultivation and Innovation Fund, Jinan University,China
文摘The role of oxygen and the generation of active radicals in the photocatalitic degradation of phenol were investigated using the eosin sensitized TiO2 as photocatalyst under visible light irradiation. Diffuse reflectance spectra show that the absorbancy range of eosin/TiO2 is expanded from 378 nm (TiO2 ) to about 600 nm. The photocatalitic degradation of phenol is almost stopped when the eosin/TiO2 system is saturated with N2 , which indicates the significance of O2 . The addition of NaN 3 (a quencher of single oxygen) causes about a 62% decrease in the phenol degradation. The phenol degradation ratio is dropped from 92% to 75% when the isopropanol (a quencher of hydroxyl radical) is present in the system. The experimental results show that there are singlet oxygen and hydroxyl radical generated in the eosin/TiO2 system under visible light irradiation. The changes of absorbancy indicate that the hydrogen peroxide might be produced. Through the analysis and comparison, it is found that the singlet oxygen is the predominant active radical for the degradation of phenol.
基金funding support from the National Natural Science Foundation of China (No. 81873014)。
文摘Objective To reduce the toxicity and side effects of arsenic trioxide(ATO)and provide a new approach for the treatment of primary liver cancer,a folic acid-modified calcium arsenite liposomal“target-controlled”drug delivery system(FA-LP-CaAs)was fabricated using the reverse microemulsion method.Methods A Malvern particle size analyzer and a transmission electron microscope were employed to determine the particle size,distribution,zeta potential and morphology of FA-LP-CaAs.Further,inductively coupled plasma emission spectrometry was employed to determine the drug loading capacity,entrapment efficiency,and in vitro release behavior of FA-LP-CaAs.To determine its toxicity in human hepatoma cells(HepG2)and human normal hepatocytes(LO2)and its effect on HepG2 cell cycle and apoptosis,the MTT method was used.Laser confocal and flow cytometry were also employed to determine the uptake of FA-LP-CaAs by cells.After establishing a mouse liver cancer model,the in vivo distribution of the drug included in the formulation was investigated using in vivo fluorescence.To evaluate the liver cancer targeting and anti-tumor effects of FALP-CaAs in vivo,the distribution of ATO in tissues and changes in tumor volume and body weight after liposomal administration were investigated using hematoxylin-eosin(HE)-stained tumor sections.Results The particle size,zeta potential and PDI of FA-LP-CaAs were(122.67±2.18)nm,(12.81±0.75)mV and 0.22±0.01,respectively,while its drug loading capacity was 18.49%±1.14%.In vitro experimental results revealed that FA-LP-CaAs had a strong killing effect on HepG2 cells.Further,the cell uptake capacity of this formulation was found to improve.Based on in vivo assessments,FA-LP-CaAs could significantly increase the distribution of ATO in tumor sites and inhibit tumor growth.Conclusions Herein,an FA-LP-CaAs formulation was successfully fabricated.This liposomal drug delivery system had a round appearance,uniform particle size,good polydispersity coefficient,evident“core-shell”structure,high drug loading capacity and pH response,tumor targeted drug delivery and sustained drug release.These findings support further research and the application of ATO as an anti-liver cancer prodrug and provide a new method for the treatment of liver cancer.
基金Project(50872001) supported by the National Natural Science Foundation of ChinaProjects(KJ2007B132, KJ2009A006Z) supported by the Scientific Research Foundation of Education Department of Anhui Province, ChinaProject(XJ200907) supported by the Foundation of Construction of Quality Project of Anhui University, China
文摘The influence of soaking time on the nonlinear electrical behavior and dielectric properties of TiO2-based varistor ceramics was investigated. Based on single sintering process, six disk samples of (Sr, Bi, Si, Ta)-doped TiO2-based varistor ceramics were fabricated by sintering at 1 250 ℃ for 0.5-5.0 h. The samples were characterized by X-ray diffraction, voltage-current characteristics, energy spectra, metallographs, breakdown voltages, and apparent dielectric constant. It is found that the breakdown electrical field intensity at a current density of 10 mA/cma decreases from 5.5 to 4.1 V/mm first and then increases to 7.0 V/mm, the nonlinear coefficient increases from 2.39 to 2.62 first and then decreases to 2.42, and the apparent dielectric constant increases from 98 200 to 1l5 049 first and then decreases to 73 865 with the soaking time increasing from 0.5 to 5.0 h. These indicate that the optimal soaking time is 2.0-3.0 h considering both nonlinear electrical behavior and dielectric properties.
文摘Objective: The aim of our study was to investigate the effect of diallyl trisulfide (DATS) combining radiation on DNA injury-repair of Esophageal cancer EC109 cells. Methods: Using 10 and 20 μg/mL DATS on EC109 cells, and taking X-ray radiation 24 h later. Investigate the radiosensitization effect of DATS on EC109 cells by clone formation, and the mechanism of DNA injury-repair by Comet Assay. Results: The clone formation resulted that DATS had radiosensitization effect on EC109 cells. Radiosensitization enhancement ratios of 10 and 20 μg/mL DATS in combination with radiation were 1.55, 1.64 (Do) and 1.43, 1.75 (Dq) respectively. In the comet assay, the TM (tail moments) of 20 μg/mL DATS combining radiation group lines at 0 h, 2 h, 6 h and 24 h were 7.16 ± 2.61, 3.65 ± 2.06, 2.09 ± 0.83, 1.45 ± 1.37 respectively. They were slightly increased than radiation group (0.95 ± 0.65, 0.11 ± 0.07, 0.1 ± 0.05, 0.11 ± 0.08) and DATS group (1.81 ± 1.23, 1.58 ± 1.40, 0.45 ± 0.25, 0.60 ± 0.40) (P < 0.01). The result showed that DATS combining radiation had the effect of increasing DNA damage and inhibiting DNA repair on EC109 cells. Conclusion: DATS has radiosensitization effect on Esophageal cancer EC109 cells. And the effect is probably related with DNA injury-repair.
文摘Phenol composition of two carnation (Dianthus caryophyllus) cvs "Gloriana" and "Roland", partially and highly resistant to F. oxysporum f. sp. dianthi, respectively, has been investigated with the aim of assessing the possible role of phenolic constituents both as biochemical markers of resistance and antifungal molecules. Analyses were performed through chromatography, NMR and MS methods. The results indicate that protocatechuic and vanillic acids are present in healthy and infected tissues of both cvs; the flavonol glycoside peltatoside. 2,6-Dimethoxybenzoic acid was detected in small amounts only in infected "Gloriana" cv while the highly resistant "Roland" cv contained the flavone datiscetin. This latter compound, due to its noticeable antifungal activity evidenced in in vitro trials, could be conceived both as a biochemical marker of resistance towards this pathogen and as a phytoanticipin.
文摘Due to important consideration of protection against lightning surge on electrical, electronic and telecommunication equipment, it was necessary to carry out a special study to look at the performance of protective devices. The study was testing performance of arresters on low voltage system. The activity was testing of arresters using steady state and impulse voltages. The arresters consisted of gas tube, zener diode, varistor and spark gap arresters, then it was made a cascade circuit between the varistor and spark gap arresters with a decoupling element. The decoupling elements were used air, iron and ferrite. The test yielded data of current and voltage on the tables and oscilloscope waveforms. The arresters had cut voltages early different from each other, namely the gas tube, zener diode, spark gap and varistor arresters were at the voltages of 500 V, 250 V, 1,000 V and 565 V respectively. The iron core decoupling element cascade circuit had the least oscillation among remaining cores.