In this paper, a Complex Wavelet Packet based Multi-Carrier Code Division Multiple Access (CWP-MC-CDMA) system uplink model is proposed, based on the analysis of the principle of MC-CDMA and the use of the optimized c...In this paper, a Complex Wavelet Packet based Multi-Carrier Code Division Multiple Access (CWP-MC-CDMA) system uplink model is proposed, based on the analysis of the principle of MC-CDMA and the use of the optimized complex wavelet packet. Considering that the base station can adopt multiple re-ceiver antennas in the uplink, we employ the Space Diversity Combining (SDC) technique to improve the sys-tem performance via multiple antennas. The uplink performance of proposed CWP-MC-CDMA system with SDC technique is investigated over Rayleigh fading channel, and corresponding bit error rate analysis is given in detail. The system can avoid the decrease of spectrum efficiency of conventional MC-CDMA due to insert-ing cyclic prefix. Theoretical analysis and simulation result show that the application of SDC technique can improve the CWP-MC-CDMA system ability to combat spatial fading and various interferences effectively. Moreover, the proposed system based on SDC technique has superior Bit Error Rate (BER) performance over the Discrete Fourier Transform (DFT) and SDC based MC-CDMA system and the real wavelet packet and SDC based MC-CDMA system.展开更多
This study focused on the development of thermophilic strain/s of a cowpea (Vigna unguiculata) compatible nitrogen fixing bacterium. A preliminary plant screening was carried out using some strains of tropical rhizobi...This study focused on the development of thermophilic strain/s of a cowpea (Vigna unguiculata) compatible nitrogen fixing bacterium. A preliminary plant screening was carried out using some strains of tropical rhizobia and cowpea. Rhizobium species CWP G34A that formed Fix+ nodules repeatedly was selected for further studies. First, it was tested for growth at high temperatures of 40 to 55oC at 5oC interval with 28oC as the control temperature. Mutagenesis was conducted on the bacterium with ethylmethane sulphonate (EMS). The wildtype and mutants generated were tested for high temperature tolerance by growing them individually in nutrient broth at 60oC for 24 hours. Optical density (670 nm) was read before and after incubation. The mutants were grouped into classes based on percentage difference in OD values obtained before and after exposure to 60oC. Rhizobium species CWP G34A produced functional pink nodules on the cowpea consistently in three different plant tests. There was no growth at all the temperatures tested except at 28oC and 40oC after 24 hours of incubation. It grew better at former (51 × 1010 Cfu/ml) than latter (11 Cfu/ml) temperature. Like the parental strain, all the mutants but one, did not grow after exposure to 60oC. Sixty degree centigrade caused various reductions in optical density (OD) values of the variants. Eleven classes of the mutants were formed with membership percentage ranging from 1 to 22%. Class 1 contains only one member while class 11 has the highest mutant population of 22% with OD difference of 0 to 10% and –90 to –100% respectively. The high percentage reduction in the OD of variants in class 11 is similar to that of the unmutated cells (–94.56%). The only mutant that survived the 60oC and grew was MU70. An increase of 1.67% in OD was obtained for MU70. Mutant MU70 therefore appeared a promising strain that can be further tested to inoculate cowpea in the dry and warm season for increased nitrogen fixation. This will provide encouraging information for farmers to grow the cowpea throughout the year particularly under high temperatures in summer in order to boost the yield of the legume.展开更多
Objectives Tumor necrosis factor-α （TNF-α） may play an important role in host＇s immune response to mycobacterium tuberculosis （M. tuberculosis） infection. This study was to investigate the association of TNF-α...Objectives Tumor necrosis factor-α （TNF-α） may play an important role in host＇s immune response to mycobacterium tuberculosis （M. tuberculosis） infection. This study was to investigate the association of TNF-α gene polymorphism with pulmonary tuberculosis （TB） among patients with coal worker＇s pneumoconiosis （CWP）. Methods A case-control study was conducted in 113 patients with confirmed CWP complicated with pulmonary TB and 113 non-TB controls with CWP. They were matched in gender, age, job, and stage of pneumoconiosis. All participants were interviewed with questionnaires and their blood specimens were collected for genetic determination with informed consent. The TNF-α gene polymorphism was determined with polymerase chain reaction of restriction fragment length polymorphism （PCR-RFLP）. Frequency of genotypes was assessed for Hardy-Weinberg equilibrium by chi-square test or Fisher＇s exact probability. Factors influencing the association of individual susceptibility with pulmonary TB were evaluated with logistic regression analysis. Gene-environment interaction was evaluated by a multiplieative model with combined OR. All data were analyzed using SAS version 8.2 software. Results No significant difference in frequency of the TNF-α-308 genotype was found between CWP complicated with pulmonary TB and non-TB controls （2,2=5.44, P=-0.07）. But difference in frequency of the TNF-α-308 A allele was identified between them （2,2-5.14, P=0.02）. No significant difference in frequencies of the TNF-α-238 genotype and allele （P=0.23 and P=0.09, respectively） was found between cases and controls either, with combined （GG and AA） OR of 3.96 （95% confidence interval of 1.30-12.09） at the -308 locus of the TNF-α gene, as compared to combination of the TNF-α-238 GG and TNF-α-308 GG genotypes. Multivariate-adjusted odds ratio of the TNF-α-238 GG and TNF-α-308 GA genotypes was 1.98 （95% CI of 1.06-3.71） for risk for pulmonary TB in patients with CWP. There was a synergic interaction between the TNF-a-308 GG genotype and body mass index （OR=4.92）, as well as an interaction between the TNF-α-308 GG genotype and history of BCG immunization or history of TB exposure. And, the interaction of the TNF-α-238 GG genotype and history of BCG immunization or TB exposure with risk for pulmonary TB in them was also indicated. Conclusions TNF-α-308 A allele is associated with an elevated risk for pulmonary TB, whereas TNF-α-238 A allele was otherwise.展开更多
基金Supported by China Postdoctoral Science Foundation, and Science Foundation of Jiangsu Province (BK2003089).
文摘In this paper, a Complex Wavelet Packet based Multi-Carrier Code Division Multiple Access (CWP-MC-CDMA) system uplink model is proposed, based on the analysis of the principle of MC-CDMA and the use of the optimized complex wavelet packet. Considering that the base station can adopt multiple re-ceiver antennas in the uplink, we employ the Space Diversity Combining (SDC) technique to improve the sys-tem performance via multiple antennas. The uplink performance of proposed CWP-MC-CDMA system with SDC technique is investigated over Rayleigh fading channel, and corresponding bit error rate analysis is given in detail. The system can avoid the decrease of spectrum efficiency of conventional MC-CDMA due to insert-ing cyclic prefix. Theoretical analysis and simulation result show that the application of SDC technique can improve the CWP-MC-CDMA system ability to combat spatial fading and various interferences effectively. Moreover, the proposed system based on SDC technique has superior Bit Error Rate (BER) performance over the Discrete Fourier Transform (DFT) and SDC based MC-CDMA system and the real wavelet packet and SDC based MC-CDMA system.
文摘This study focused on the development of thermophilic strain/s of a cowpea (Vigna unguiculata) compatible nitrogen fixing bacterium. A preliminary plant screening was carried out using some strains of tropical rhizobia and cowpea. Rhizobium species CWP G34A that formed Fix+ nodules repeatedly was selected for further studies. First, it was tested for growth at high temperatures of 40 to 55oC at 5oC interval with 28oC as the control temperature. Mutagenesis was conducted on the bacterium with ethylmethane sulphonate (EMS). The wildtype and mutants generated were tested for high temperature tolerance by growing them individually in nutrient broth at 60oC for 24 hours. Optical density (670 nm) was read before and after incubation. The mutants were grouped into classes based on percentage difference in OD values obtained before and after exposure to 60oC. Rhizobium species CWP G34A produced functional pink nodules on the cowpea consistently in three different plant tests. There was no growth at all the temperatures tested except at 28oC and 40oC after 24 hours of incubation. It grew better at former (51 × 1010 Cfu/ml) than latter (11 Cfu/ml) temperature. Like the parental strain, all the mutants but one, did not grow after exposure to 60oC. Sixty degree centigrade caused various reductions in optical density (OD) values of the variants. Eleven classes of the mutants were formed with membership percentage ranging from 1 to 22%. Class 1 contains only one member while class 11 has the highest mutant population of 22% with OD difference of 0 to 10% and –90 to –100% respectively. The high percentage reduction in the OD of variants in class 11 is similar to that of the unmutated cells (–94.56%). The only mutant that survived the 60oC and grew was MU70. An increase of 1.67% in OD was obtained for MU70. Mutant MU70 therefore appeared a promising strain that can be further tested to inoculate cowpea in the dry and warm season for increased nitrogen fixation. This will provide encouraging information for farmers to grow the cowpea throughout the year particularly under high temperatures in summer in order to boost the yield of the legume.
基金supported by grants from China National Programs for Science and Technology Development (Grant No. 2003BA712A11-24)Scientific Research Fund of North China Coal Medical College (Grant No. 2005-14)
文摘Objectives Tumor necrosis factor-α （TNF-α） may play an important role in host＇s immune response to mycobacterium tuberculosis （M. tuberculosis） infection. This study was to investigate the association of TNF-α gene polymorphism with pulmonary tuberculosis （TB） among patients with coal worker＇s pneumoconiosis （CWP）. Methods A case-control study was conducted in 113 patients with confirmed CWP complicated with pulmonary TB and 113 non-TB controls with CWP. They were matched in gender, age, job, and stage of pneumoconiosis. All participants were interviewed with questionnaires and their blood specimens were collected for genetic determination with informed consent. The TNF-α gene polymorphism was determined with polymerase chain reaction of restriction fragment length polymorphism （PCR-RFLP）. Frequency of genotypes was assessed for Hardy-Weinberg equilibrium by chi-square test or Fisher＇s exact probability. Factors influencing the association of individual susceptibility with pulmonary TB were evaluated with logistic regression analysis. Gene-environment interaction was evaluated by a multiplieative model with combined OR. All data were analyzed using SAS version 8.2 software. Results No significant difference in frequency of the TNF-α-308 genotype was found between CWP complicated with pulmonary TB and non-TB controls （2,2=5.44, P=-0.07）. But difference in frequency of the TNF-α-308 A allele was identified between them （2,2-5.14, P=0.02）. No significant difference in frequencies of the TNF-α-238 genotype and allele （P=0.23 and P=0.09, respectively） was found between cases and controls either, with combined （GG and AA） OR of 3.96 （95% confidence interval of 1.30-12.09） at the -308 locus of the TNF-α gene, as compared to combination of the TNF-α-238 GG and TNF-α-308 GG genotypes. Multivariate-adjusted odds ratio of the TNF-α-238 GG and TNF-α-308 GA genotypes was 1.98 （95% CI of 1.06-3.71） for risk for pulmonary TB in patients with CWP. There was a synergic interaction between the TNF-a-308 GG genotype and body mass index （OR=4.92）, as well as an interaction between the TNF-α-308 GG genotype and history of BCG immunization or history of TB exposure. And, the interaction of the TNF-α-238 GG genotype and history of BCG immunization or TB exposure with risk for pulmonary TB in them was also indicated. Conclusions TNF-α-308 A allele is associated with an elevated risk for pulmonary TB, whereas TNF-α-238 A allele was otherwise.
