Three experiments for the simulation of typhoon Sinlaku （2002） over the western North Pacific are performed in this study by using the Canadian Mesoscale Compressible Community （MC2） atmospheric model. The objecti...Three experiments for the simulation of typhoon Sinlaku （2002） over the western North Pacific are performed in this study by using the Canadian Mesoscale Compressible Community （MC2） atmospheric model. The objective of these simulations is to investigate the air-sea interaction during extreme weather conditions, and to determine the sensitivity of the typhoon evolution to the sea surface temperature （SST） cooling induced by the typhoon. It is shown from the three experiments that the surface heat fluxes have a substantial influence on the slow-moving cyclone over its lifetime. When the SST in the East China coastal ocean becomes 1℃ cooler in the simulation, less latent heat and sensible heat fluxes from the underlying ocean to the cyclone tend to reduce the typhoon intensity. The cyclone is weakened by 7 hPa at the time of its peak intensity. The SST cooling also has impacts on the vertical structure of the typhoon by weakening the warm core and drying the eye wall. With a finer horizontal resolution of （1/6）° × （1/6）°, the model produces higher surface wind, and therefore more surface heat fluxes are emitted from the ocean surface to the cyclone, in the finer-resolution MC2 grid compared with the relatively lower resolution of 0.25° × 0.25° MC2 grid.展开更多
This paper describes the set up and application of a non hydrostatic Canadian meteorological numerical model (MC2) for mesoscale simulations of wind field and other meteorological parameters over the complex terrain...This paper describes the set up and application of a non hydrostatic Canadian meteorological numerical model (MC2) for mesoscale simulations of wind field and other meteorological parameters over the complex terrain of Hong Kong. Results of the simulations of one case are presented and compared with the results of radiosonde and aircraft measurements. The model is proved capable of predicting high resolution, three dimensional fields of wind and other meteorological parameters within the Hong Kong territory, using reasonable computer time and memory resources.展开更多
Adrenocorticotropin hormone (ACTH), which is secreted in response to psychological stress, plays an important role in the hair cycle. This study examined the mechanism by which ACTH affects the hair cycle using mice d...Adrenocorticotropin hormone (ACTH), which is secreted in response to psychological stress, plays an important role in the hair cycle. This study examined the mechanism by which ACTH affects the hair cycle using mice deficient in melanocortin receptor-2(MC2R<sup>-/-</sup>), which is a main receptor for ACTH. We observed the hair cycle using female MC2R<sup>-/-</sup> mice at 15 weeks old and five days old to determine whether there were any age-dependent differences. The 15-week-old MC2R<sup>-/-</sup> mice showed the anagen phase for all mice. On the other hand, all of the MC2R<sup>+/+</sup> mice showed the telogen phase at the same age. Moreover, in the five-day-old mice, the hair growth of the MC2R<sup>-/-</sup> mice occurred earlier than in the MC2R<sup>+/+</sup> mice. Both the 15-week-old and five-day-old MC2R<sup>-/-</sup> mice had higher levels of ACTH and alpha-melanocyte stimulating hormone in the blood than did the MC2R<sup>+/+</sup> mice. In addition, in the 15-week-old MC2R<sup>-/-</sup> mice, the hair cycle shifted to the telogen phase following the administration of a cyclic guanosine monophosphate (cGMP) inhibitor and MC1R/MC5R inhibitor. In the five-day-old MC2R<sup>-/-</sup> mice, the hair growth was slowed by the administration of corticosterone. These results suggest that the ACTH/MC2R system has an important role in the hair cycle.展开更多
Background Infantile spasms is a severe epileptic encephalopathy, which is refractory to conventional antiepileptic drugs. Adrenocorticotropic hormone （ACTH） has been the major therapy for infantile spasms; however,...Background Infantile spasms is a severe epileptic encephalopathy, which is refractory to conventional antiepileptic drugs. Adrenocorticotropic hormone （ACTH） has been the major therapy for infantile spasms; however, ACTH therapy is ineffective for some patients. The variations in the receptor genes can contribute to antiepileptic drug resistance. This study was to elucidate the possible associations between the variations of the MC2R gene and ACTH responsiveness in patients with infantile spasms. Methods We screened for variations in the promoter and coding region of the MC2R gene in 91 Chinese patients with infantile spasms and 94 controls, using PCR and a direct sequencing method. The frequencies of the genotypes, alleles and reconstructed haplotypes were analyzed in the cases and controls. The association between ACTH responsiveness and genetic variations of the MC2R gene was also assessed. Results Four single nucleotide polymorphisms （SNPs） were identified in the MC2R promoter, one of which was a novel specimen at position-2 from the transcription start site ATT, -2T〉C. Three SNPs （rs1893220, rs2186944 and -2T〉C） showed a significant difference between the cases and controls （P 〈0.05 for all）. The frequency of the common TCCT haplotype carrying four-SNP major alleles was significantly lower in the cases （39%） than in the controls （60%） （P=-0.00003）. The homozygous carriers of the TCCT haplotype had a much lower relative risk than the non-carriers （RR=O.42, 95%C/ 0.26-0.70, P=-0.0001）. ACTH responsiveness was strongly associated with the TCCT haplotype （P=-0.000082）. Compared with non-carriers of the TCCT haplotype, the homozygous and heterozygous carriers were more responsive to ACTH therapy （P=0.0002; P=-0.0003, respectively）. Conclusions Our results indicated that the TCCT haplotype in the MC2R promoter is strongly associated with the responsiveness of the ACTH therapy performed on patients with infantile spasms. The polymorphisms of the MC2R promoter might be one important factor that influences the efficacy of ACTH therapy on infantile spasms.展开更多
文摘Three experiments for the simulation of typhoon Sinlaku （2002） over the western North Pacific are performed in this study by using the Canadian Mesoscale Compressible Community （MC2） atmospheric model. The objective of these simulations is to investigate the air-sea interaction during extreme weather conditions, and to determine the sensitivity of the typhoon evolution to the sea surface temperature （SST） cooling induced by the typhoon. It is shown from the three experiments that the surface heat fluxes have a substantial influence on the slow-moving cyclone over its lifetime. When the SST in the East China coastal ocean becomes 1℃ cooler in the simulation, less latent heat and sensible heat fluxes from the underlying ocean to the cyclone tend to reduce the typhoon intensity. The cyclone is weakened by 7 hPa at the time of its peak intensity. The SST cooling also has impacts on the vertical structure of the typhoon by weakening the warm core and drying the eye wall. With a finer horizontal resolution of （1/6）° × （1/6）°, the model produces higher surface wind, and therefore more surface heat fluxes are emitted from the ocean surface to the cyclone, in the finer-resolution MC2 grid compared with the relatively lower resolution of 0.25° × 0.25° MC2 grid.
文摘This paper describes the set up and application of a non hydrostatic Canadian meteorological numerical model (MC2) for mesoscale simulations of wind field and other meteorological parameters over the complex terrain of Hong Kong. Results of the simulations of one case are presented and compared with the results of radiosonde and aircraft measurements. The model is proved capable of predicting high resolution, three dimensional fields of wind and other meteorological parameters within the Hong Kong territory, using reasonable computer time and memory resources.
文摘Adrenocorticotropin hormone (ACTH), which is secreted in response to psychological stress, plays an important role in the hair cycle. This study examined the mechanism by which ACTH affects the hair cycle using mice deficient in melanocortin receptor-2(MC2R<sup>-/-</sup>), which is a main receptor for ACTH. We observed the hair cycle using female MC2R<sup>-/-</sup> mice at 15 weeks old and five days old to determine whether there were any age-dependent differences. The 15-week-old MC2R<sup>-/-</sup> mice showed the anagen phase for all mice. On the other hand, all of the MC2R<sup>+/+</sup> mice showed the telogen phase at the same age. Moreover, in the five-day-old mice, the hair growth of the MC2R<sup>-/-</sup> mice occurred earlier than in the MC2R<sup>+/+</sup> mice. Both the 15-week-old and five-day-old MC2R<sup>-/-</sup> mice had higher levels of ACTH and alpha-melanocyte stimulating hormone in the blood than did the MC2R<sup>+/+</sup> mice. In addition, in the 15-week-old MC2R<sup>-/-</sup> mice, the hair cycle shifted to the telogen phase following the administration of a cyclic guanosine monophosphate (cGMP) inhibitor and MC1R/MC5R inhibitor. In the five-day-old MC2R<sup>-/-</sup> mice, the hair growth was slowed by the administration of corticosterone. These results suggest that the ACTH/MC2R system has an important role in the hair cycle.
基金This study was supported by the grants from the National Natural Science Foundation of China （No. 30770747）, the Beijing Municipal Natural Science Foundation （No. 7081002, No. 7042024） and the Capital Development Foundation of Beijing （No. 2003-2007）.
文摘Background Infantile spasms is a severe epileptic encephalopathy, which is refractory to conventional antiepileptic drugs. Adrenocorticotropic hormone （ACTH） has been the major therapy for infantile spasms; however, ACTH therapy is ineffective for some patients. The variations in the receptor genes can contribute to antiepileptic drug resistance. This study was to elucidate the possible associations between the variations of the MC2R gene and ACTH responsiveness in patients with infantile spasms. Methods We screened for variations in the promoter and coding region of the MC2R gene in 91 Chinese patients with infantile spasms and 94 controls, using PCR and a direct sequencing method. The frequencies of the genotypes, alleles and reconstructed haplotypes were analyzed in the cases and controls. The association between ACTH responsiveness and genetic variations of the MC2R gene was also assessed. Results Four single nucleotide polymorphisms （SNPs） were identified in the MC2R promoter, one of which was a novel specimen at position-2 from the transcription start site ATT, -2T〉C. Three SNPs （rs1893220, rs2186944 and -2T〉C） showed a significant difference between the cases and controls （P 〈0.05 for all）. The frequency of the common TCCT haplotype carrying four-SNP major alleles was significantly lower in the cases （39%） than in the controls （60%） （P=-0.00003）. The homozygous carriers of the TCCT haplotype had a much lower relative risk than the non-carriers （RR=O.42, 95%C/ 0.26-0.70, P=-0.0001）. ACTH responsiveness was strongly associated with the TCCT haplotype （P=-0.000082）. Compared with non-carriers of the TCCT haplotype, the homozygous and heterozygous carriers were more responsive to ACTH therapy （P=0.0002; P=-0.0003, respectively）. Conclusions Our results indicated that the TCCT haplotype in the MC2R promoter is strongly associated with the responsiveness of the ACTH therapy performed on patients with infantile spasms. The polymorphisms of the MC2R promoter might be one important factor that influences the efficacy of ACTH therapy on infantile spasms.
