λ噬菌体操纵基因和调控蛋白相互作用网络及溶原态/裂解态转变特性的动力学研究

根据大肠杆菌中λ噬菌体操纵基因与调控蛋白相互作用特点,提出操纵基因与调控蛋白相互作用模型.利用动力学方法,得到了两种调控蛋白浓度随时间变化的关系和在一定的时间范围内两种调控蛋白之间的关系,并且得到调控系统的稳态性质,进而分析调控系统溶原态/裂解态的转变特性.

Effect of Osmotic Pressure on Mycoplasma hyopneumoniae Strain 168

[Objective] This study aimed to investigate the effect of hypertonic solution on the morphology,size,incubation time and cell viability of Mycoplasma hyopneumoniae（Mhp）.[Method] Mhp was stimulated by using NaCl hypertonic solution with a final concentration of 1.8% for 1,2,4,6 and 8 min,respectively.After staining and microscopic examination,the particle size and CCU（color change unit） were determined,and PCR identification was conducted.[Result] After treated with hypertonic solution for different time,Mhp was shrunken and turned round,the particle size was reduced,and the cell number rapidly decreased or even disappeared after 2 min.CCU was reduced by a gradient,and the observation time was extended for 1 d.The target band of Mhp could be amplified from samples after treated with hypertonic solution for different time.After treated with 1.8% NaCl solution for 1-6 min,Mhp changed in the morphology and size but still had viability.[Conclusion] This study provided reference data for exploring the entrance of Mhp into blood circulation after intramuscular injection and a new immunization route of swine Mycoplasma pneumonia vaccine.

Effects of Aerosols on Fogs Observed in the North China Plain

Fog simulation and prediction are becoming increasingly important in China because of the great impact of fog on traffic and other human activities. More studies are needed to have a better understanding of the formation mechanisms and life cycles of fogs. This work uses data from two fog cases observed in Wuqing, Tianjin, in 2009. The data include aerosol size distribution, fog droplet size distribution, fog liquid water content, and meteorological properties. The results show that increasing aerosols can increase the number concentration of fog droplets and decrease fog droplet size, which is consistent with the first aerosol indirect effect found in clouds. It is also shown that increased aerosols can lead to lower visibility in fogs. This work demonstrates that the first aerosol indirect effect plays an important role in fogs.

Photoassociation of Atomic BEC within Mean-Field Approximation： Exact Solutions

We propose an exactly solvable method to study the coherent two-colour photoassociation of an atomic Bose- Einstein condensate, by linearizing the bilinear atom-molecule coupling, which allows us to conveniently probe the quantum dynamics and statistics of the system. By preparing different initial states of the atomic condensate, we can observe very different quantum statistical properties of the system by exactly calculating the quadrature- squeezed and mode-correlated functions.

Reactive protein, plasminogen activator inhibitor type-1 （PAI-1） levels, PAI-1 promoter 4G/5G polymorphism and acute myocardial infarction

Objective To investigate the relationship between CRP, plasminogen activator inhibitor type 1 （PAI-1） levels, PAI-1 gene promoter 4G/5G polymorphism and the type of acute myocardial infarction （ST elevation myocardial infarction, STEMI vs the non-ST elevation Myocardial infarction, NSTEMI）. Methods One hundred seventy-six consecutive patients with AMI were included for the study, of whom 60 had STEMI and 56 had NSTEMI, and 60 adults without cardiovascular and cerebrovascular disease were selected as controls. Blood samples were obtained from patients within 6 h of AMI and the plasma PAI-1, CRP, and the gene polymorphism were measured. Results Plasma levels of PAI- 1 and CRP were higher in AMI groups, compared those in the control group, and plasma levels of PAI-1 were significantly higher in patients with STEMI compared to those with NSTEMI （80.12ng/ml VS.73.01ng/ml, P 〈0.01）, while CRP levels were not significantly different between patient with STEMI and NSTEMI （3.87 ± 0.79 mg/ml VS.4.01 ±0.69mg/ml, P〉0.05）. PAI-1 levels presented a significant correlation with CRP levels in the NSTEMI subjects. However, PAI-1 and CRP levels could explain the lack of a significant relationship between them in control and STEMI subjects.The frequencies of 4G/4G genotype in the AMI group were higher than those in the control group and higher in patient with STEMI than in patient with NSTEMI. Plasma levels of PAI-1 in subjects with 4G/4G genotype were significantly increased as compared to those in subjects with 4G/5G and 5G/5G genotype. Conclusions Plasma PAI-1 levels were associated with different myocardial infarction type, and PAI-1 promoter 4G/5G polymorphisms and CRP may be related to plasma PAI-1 levels

Relationship between gene polymorphism of the PAI-1 promoter and myocardial infarction

abstractObjective To investigate the association between gene polymorphism of the plasminogen activator inhibitor 1 (PAI 1) and myocardial infarction (MI) in Chinese Methods PAI 1 genotyping with polymerase chain reaction restriction fragment length polymorphism (PCR RFLP) and allele specific polymerase chain reaction (ASPCR) was performed in 87 myocardial infarction patients and 92 unrelated healthy controls All subjects'clinical features and PAI 1 activity were tested Results There were two polymorphisms within the promoter, a G/A single base substitution polymorphism upstream at -844?bp, and a single guanosine deletion/insertion 4G/5G polymorphism -675?bp upstream from the start of transcription Significant differences between the patients and the controls were observed neither for the frequencies of the GG, GA and AA genotypes nor for the PAI 1 activities of these three types But for the 4G/5G polymorphism, there were significant differences between patients and controls for the frequencies of the 4G/4G, 4G/5G and 5G/5G genotypes ( P <0 05) In the MI group, the PAI 1 activity of the 4G/4G type was significantly higher than that of the 5G/5G type ( P <0 05) Further more, a positive correlation between the glucose level and PAI 1 activity was found ( r =0 34, P =0 02) Conclusion This study indicates that the 4G/5G gene polymorphism of PAI 1 is associated with myocardial infarction, that 4G/4G type is probably an important hereditary risk factor, and that glucose has functional importance in regulating PAI 1 activity

The influence of temperature on the PLC effect in Al-Mg alloy

An experimental investigation of the influence of temperature on the Portevin-Le Chatelier(PLC) effect in Al-Mg alloy is conducted.Under a certain strain rate,the PLC effect is present in the temperature range of 223-328 K.The serration amplitude increases monotonically with increasing temperature,whereas the behaviors of the serration period and the critical strain with temperature include a descending branch under corresponding low temperature range and an ascending branch under corresponding high temperature range.The analysis in relation with dynamic strain aging(DSA) indicates that the temperature plays an important role in the PLC effect by dictating the solubility and the diffusibility of solute atoms.Both the concentration and the diffusibility of solute atoms contribute to increasing the serration amplitude.Under the descending branch temperature range,the serration period mainly depends on the preparation phase and the dominant factor of critical strain is the velocity of dislocations.However,under the ascending branch temperature range,the serration period mainly depends on the pinning phase and the dominant factor of critical strain is the applied stress required for unpinning.