Let G = （V, E） be a graph without isolated vertices. A set S lohtain in V is a domination set of G if every vertex in V - S is adjacent to a vertex in S, that is N[S] = V. The domination number of G, denoted by γ（...Let G = （V, E） be a graph without isolated vertices. A set S lohtain in V is a domination set of G if every vertex in V - S is adjacent to a vertex in S, that is N[S] = V. The domination number of G, denoted by γ（G）, is the minimum cardinality of a domination set of G. A set S lohtain in V is a paired-domination set of G if S is a domination set of G and the induced subgraph G[S] has a perfect matching. The paired-domination number, denoted by γpr（G）, is defined to be the minimum cardinality of a paired-domination set S in G. A subset S lohtain in V is a power domination set of G if all vertices of V can be observed recursively by the following rules： （i） all vertices in N[S] are observed initially, and （ii） if an observed vertex u has all neighbors observed except one neighbor v, then v is observed （by u）. The power domination number, denoted by γp（G）, is the minimum cardinality of a power domination set of G. In this paper, the constructive characterizations for trees with γp=γ and γpr = γp are provided respectively.展开更多
Objective: To observe the effect of statins on preventing paroxysmal atrial fibrillation (PAF) after pacemaker imlantation in patients with sick sinus syndrome. Materials and Methods: 68 patients were selected in whic...Objective: To observe the effect of statins on preventing paroxysmal atrial fibrillation (PAF) after pacemaker imlantation in patients with sick sinus syndrome. Materials and Methods: 68 patients were selected in which the pacemakers had been implanted due to sick sinus syndrome,and were randomly divided into a statin treatment group and a control group. After the pacemaker implantation, only the patients in treatment group were given 20 mg atorvastatin once per night,with other conditions basically similar to those in the control group. At the 3rd, 9th, 15th, and 21st months after the implantation, the pacemakers were programmed, and the PAF-related information stored in the pacemaker were recalled and analyzed statistically. Results: After the administration of statins for 9 months since the imlantation, the occurrence rates of PAF in the treatment group was relatively lower than those in the control group. After further administration of statins for 15 months, both the occurrence rate of PAF and the burden of atrial fibrillation in the treatment group had significantly declined. After continuous administration of statins for 21 months, both the occurrence rate of PAF and the burden of atrial fibrillation in the treatment group were significantly lower than those in the control group. Conclusion: Long-term administration of statins can reduce the risk of PAF after the implantation of a pacemaker in patients with sick sinus syndrome.展开更多
基金Supported in part by National Natural Science Foundation of China (60673048 10471044)+1 种基金National Basic Research Program (2003CB318003)Shanghai Leading Academic Discipline Project (B407)
文摘Let G = （V, E） be a graph without isolated vertices. A set S lohtain in V is a domination set of G if every vertex in V - S is adjacent to a vertex in S, that is N[S] = V. The domination number of G, denoted by γ（G）, is the minimum cardinality of a domination set of G. A set S lohtain in V is a paired-domination set of G if S is a domination set of G and the induced subgraph G[S] has a perfect matching. The paired-domination number, denoted by γpr（G）, is defined to be the minimum cardinality of a paired-domination set S in G. A subset S lohtain in V is a power domination set of G if all vertices of V can be observed recursively by the following rules： （i） all vertices in N[S] are observed initially, and （ii） if an observed vertex u has all neighbors observed except one neighbor v, then v is observed （by u）. The power domination number, denoted by γp（G）, is the minimum cardinality of a power domination set of G. In this paper, the constructive characterizations for trees with γp=γ and γpr = γp are provided respectively.
文摘Objective: To observe the effect of statins on preventing paroxysmal atrial fibrillation (PAF) after pacemaker imlantation in patients with sick sinus syndrome. Materials and Methods: 68 patients were selected in which the pacemakers had been implanted due to sick sinus syndrome,and were randomly divided into a statin treatment group and a control group. After the pacemaker implantation, only the patients in treatment group were given 20 mg atorvastatin once per night,with other conditions basically similar to those in the control group. At the 3rd, 9th, 15th, and 21st months after the implantation, the pacemakers were programmed, and the PAF-related information stored in the pacemaker were recalled and analyzed statistically. Results: After the administration of statins for 9 months since the imlantation, the occurrence rates of PAF in the treatment group was relatively lower than those in the control group. After further administration of statins for 15 months, both the occurrence rate of PAF and the burden of atrial fibrillation in the treatment group had significantly declined. After continuous administration of statins for 21 months, both the occurrence rate of PAF and the burden of atrial fibrillation in the treatment group were significantly lower than those in the control group. Conclusion: Long-term administration of statins can reduce the risk of PAF after the implantation of a pacemaker in patients with sick sinus syndrome.
