Stochastic Dynamics of Gene Switching and Energy Dissipation for Gene Expression.

Stochastic dynamics of gene switching and energy dissipation for gene expression are largely unknown, mainly due to the complexity of non-equilibrium mechanisms. Here, based on an important double-deck loop model, the stochastic mechanisms of gene switching and energy dissipation are studied. First, the probability distributions of steady states are calculated theoretically. It is found that the signal can strengthen the choice of gene switching between the "off" and "on" states. Our analysis of energy consumption illustrates that, compared with the synthesis and degradation of proteins, the process of gene switching costs little energy. Our theoretical analysis reveals some interesting insights into the determination of cell state and energy dissipation for gene expression.

Oligo(ethylene glycol)-Functionalized Ratiometric Fluorescent Probe for the Detection of Hydrazine in Vitro and in Vivo.

Hydrazine induced toxicity causes serious harm to the health of humans. The detection of N2H4 in vitro and in vivo has attracted a great deal of attention, especially in the context of fluorescent probes. Although some fluorescent N2H4 probes have been reported, only a few operate in purely aqueous media and, as a result, require the use of organic cosolvents which hinders their use in analysis of real samples. In addition, most of the current N2H4 probes are either "off-on" or "on-off" types, in which it is difficult to eliminate interference from background fluorescence commonly occurring in in vitro and in vivo systems. Furthermore, some probes are unable to differentiate hydrazine from other organic amines. To address the above problems, we developed a novel oligo(ethylene glycol)-functionalized fluorescent probe for the detection of N2H4. The probe, which has a donor-π-acceptor (D-π-A)-type structure, is water-soluble, and it can be utilized to selectively detect N2H4 in both colorimetric and ratiometric mode. Furthermore, the probe is able to differentiate hydrazine from other organic amines and can be used to detect hydrazine vapor and for imaging A549 cells and zebrafish.

[Treatment of developmental dislocation of the hip with improved Pemberton method].

OBJECTIVE: To find a more perfect method of treating developmental dislocation of the hip(DDH). METHODS: From March 1994 to December 2002, on the basis of the ordinary operative method, Pemberton method was improved for 48 cases of DDH 49 articulatio coxae which had superficial and small acetabula but big heads of femur. Osteotomy points were moved higher to enlarge area of bone flap turned over. A piece of full thickness ilium including periosteum was removed as a free bony graft. Capsula articularis growing thicker was made into 2 layers, of which the inner layer was used to tighten articularis and the outer layer was used to stabilize bone flap. RESULTS: All patients were followed up for 18 months to 5 years, the function of articulatio coxae and degree of bony union, inclusion area to head of femur and ischemic necrosis of femoral head were observed through X-ray. According to Zhou Yongde's criteria for the curative effect of congenital dislocation of the hip, there were 18 cases of 26-30 scores(3 hips), 27 cases of 21-25 scores, 2 cases of 16-20 scores(3 hips), and 1 case under 15 scores, and the total superior rate was 93.8%. CONCLUSION: Improved Pemberton method can enlarge inclusion area to head of femur, avoid decreasing acetabular volume, and stabilize articulatio well, which made operative indication bigger than original Pemberton method.