Roles of the Bloom's syndrome helicase in the maintenance of genome stability

The RecQ family of DNA helicases is highly conserved in evolution from bacteria to humans. Of the five known human RecQ family members, three (BLM, WRN and RECQ4, which cause Bloom's syndrome, Werner's syndrome and Rothmund-Thomson syndrome respectively) are mutated in distinct clinical disorders associated with cancer predisposition and/or premature aging. BLM forms part of a multienzyme complex including topoisomerase IIIalpha, replication protein A and a newly identified factor called BLAP75. Together, these proteins play a role in the resolution of DNA structures that arise during the process of homologous recombination repair. In the absence of BLM, cells show genomic instability and a high incidence of sister-chromatid exchanges. In addition to a DNA structure-specific helicase activity, BLM also catalyses Holliday-junction branch migration and the annealing of complementary single-stranded DNA molecules

Seismic Effect of the Offshore Structure Under Different Earthquake Loadings

Peninsular Malaysia is most affected by the distant Sumatra subduction zone earthquake. Meanwhile, Eastern Malaysia was subjected to major Philippine and Indonesian earthquake. Most of the offshore platform is at Terengganu, Sabah, and Sarawak. More than 65% of the offshore platform structure exceed the range of design between 20-30 years. This research aims to determine the vulnerability and risk analysis for the existing 3-legged offshore platform under earthquake load, study the behaviors of an offshore platform under major or minor earth-quake loading, and study the dynamic characteristic of an offshore platform. SAP 2000 is use to analyses and modelling the 3-legged offshore platform. In SAP 2000, the response spectrum, time history, and free vibration will be performed. The mixed load of the platform consists of dead load, imposed load, environment loads, and earthquake load. The position of the offshore platform has referred to American Petroleum Institute (API) standard. The major earthquake under off-shore platform is El-Centro and the minor is Aceh compared to time history. Based on this study, Malaysia can withstand this low seismic activity, overall joint acceleration, velocity and displacement

Seismic Effect of the Offshore Structure Under Different Earthquake Loadings

Peninsular Malaysia is most affected by the distant Sumatra subduction zone earthquake. Meanwhile, Eastern Malaysia was subjected to major Philippine and Indonesian earthquake. Most of the offshore platform is at Terengganu, Sabah, and Sarawak. More than 65% of the offshore platform structure exceed the range of design between 20-30 years. This research aims to determine the vulnerability and risk analysis for the existing 3-legged offshore platform under earthquake load, study the behaviors of an offshore platform under major or minor earth-quake loading, and study the dynamic characteristic of an offshore platform. SAP 2000 is use to analyses and modelling the 3-legged offshore platform. In SAP 2000, the response spectrum, time history, and free vibration will be performed. The mixed load of the platform consists of dead load, imposed load, environment loads, and earthquake load. The position of the offshore platform has referred to American Petroleum Institute (API) standard. The major earthquake under off-shore platform is El-Centro and the minor is Aceh compared to time history. Based on this study, Malaysia can withstand this low seismic activity, overall joint acceleration, velocity and displacement

Modeling and identification of a class of servomechanism systems with stick-slip friction

This paper describes a technique for modeling and identifying a class of nonlinear servomechanism systems with stick-slip friction. The physics of the stick-slip friction is considered in modeling the process. Identification of the system parameters is formulated as a nonlinear optimization problem. A modified simplex algorithm is pro- I Introduction When operating with small amplitude and low frequency signal input, the presence of stick-slip friction in a servomechanism cannot be ignored. To accurately predict or simulate the performance of the system, the effects of friction on the motor behavior should be taken into consideration by appropriate modeling of the friction. This paper describes a modeling and identification technique for a class of servomechanism systems with stick-slip friction. In the paper [1], Karnopp presented a novel model for describing the effect of stick-slip friction in mechanical dynamic systems. The model proposed by Karnopp takes the physics of the stick-slip friction process into account by considering the rate of change of momentum in the mechanical system. The main parameters in the model include the inertia of the system, the slip coefficient, the threshold for the momentum rate and the saturation stick force. The stick-slip friction model of Karnopp is adapted to a class of servomechanism in this paper. For the present discussion, the dc servomotor is considered. The proposed adaptation can be extended to other classes of servomechanisms. This paper next addresses an identification technique and the choice of input signals for estimating the parameters associated with the nonlinear stick-slip model. The identification problem is posed as an optimization problem to be solved using nonlinear programming methods II Modeling A typical armature-controlled dc motor is shown in 324/Vol. 110, SEPTEMBER 1988 The schematic block diagram for the system is given in The friction torque T f consists of two components, r s i ip and r stick . In the slip region where \6 m \>Dj, the switching Rm Lrr Transactions of the AS M

Squalus acanthias, spiny dogfish

While there are reported subpopulations of Squalus acanthias (Linnaeus, 1758) elsewhere in the world, the North Pacific subpopulation is now considered a separate species, Squalus suckleyi (Girard, 1854) (see Ebert et al. 2010). Further taxonomic studies on this genus are required, including in relation to Mediterranean and Black Sea subpopulations. In Europe, three subpopulations are inferred to occur.Fil: Finucci, B.. National Institute of Water and Atmospheric Research; Nueva ZelandaFil: Cheok, J.. University Fraser Simon; CanadáFil: Chiaramonte, Gustavo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia". Estación Hidrobiológica de Puerto Quequén (sede Quequén); ArgentinaFil: Cotton, C. F.. Florida State University; Estados UnidosFil: Dulvy, N. K.. University Fraser Simon; CanadáFil: Kulka, D. W.. No especifíca; ArgentinaFil: Neat, F. C.. No especifíca; ArgentinaFil: Pacoureau, N.. University Fraser Simon; CanadáFil: Rigby, C. L.. James Cook University; AustraliaFil: Tanaka, S.. No especifíca; ArgentinaFil: Walker, T. I.. University of Melbourne; Australi

Structure vulnerability and risk analysis of 3-legged offshore structure

Peninsular Malaysia is most affected by the distant Sumatra subduction zone earthquake. Meanwhile, Eastern Malaysia was subjected to major Philippine and Indonesian earthquake. Most of the offshore platform is at Terengganu, Sabah, and Sarawak. More than 65% of the offshore platform structure exceed the range of design between 20-30 years. This research aims to determine the vulnerability and risk analysis for the existing 3-legged offshore platform under earthquake load, study the behaviors of an offshore platform under major or minor earthquake loading, and study the dynamic characteristic of an offshore platform. SAP 2000 is use to analyses and modelling the 3-legged offshore platform. In SAP 2000, the response spectrum, time history, and free vibration will be performed. The mixed load of the platform consists of dead load, imposed load, environment loads, and earthquake load. The position of the offshore platform has referred to American Petroleum Institute (API) standard. The major earthquake under off-shore platform is El-Centro and the minor is Aceh compared to time history. Based on this study, Malaysia can withstand this low seismic activity, overall joint acceleration, velocity and displacement

Structure vulnerability and risk analysis of 4-legged offshore structure

Offshore structures are commonly used in oil and gas collecting sector. This industry is one of the major economic sector in Malaysia. Since distant earthquakes from neighbour countries (Indonesia and Philippines) had caused significant structural damages in the past few years, the perfomance level of offshore due to seismic effect need to be undergone detailed investigation. Therefore, this research aims to investigate the vulnerability and analyze the risk of 4-legged fixed offshore structure under different excitations. In order to achieve the objectives, SAP 2000 was chosen to analyze the offshore structure modelling by referring to the API (American Petroleum Institute) criteria. Time history, response spectrum and free vibration analysis have been performed. The behaviour of the offshore structure was observed and evaluated through the natural frequencies and periods. Meanwhile, results outcome of the joint displacement, velocity, and acceleration represented the dynamic characteristic of the structure. The 4-legged fixed offshore structure categorized as Immediate Occupancy (IO) based on FEMA 356 guidelines. From the results, it showed that existing 4-legged offshore structures in Malaysia are capable to resist seismic loads and in stable condition

Seismic Effect of the Offshore Structure Under Different Earthquake Loadings

Peninsular Malaysia is most affected by the distant Sumatra subduction zone earthquake. Meanwhile, Eastern Malaysia was subjected to major Philippine and Indonesian earthquake. Most of the offshore platform is at Terengganu, Sabah, and Sarawak. More than 65% of the offshore platform structure exceed the range of design between 20-30 years. This research aims to determine the vulnerability and risk analysis for the existing 3-legged offshore platform under earthquake load, study the behaviors of an offshore platform under major or minor earth-quake loading, and study the dynamic characteristic of an offshore platform. SAP 2000 is use to analyses and modelling the 3-legged offshore platform. In SAP 2000, the response spectrum, time history, and free vibration will be performed. The mixed load of the platform consists of dead load, imposed load, environment loads, and earthquake load. The position of the offshore platform has referred to American Petroleum Institute (API) standard. The major earthquake under off-shore platform is El-Centro and the minor is Aceh compared to time history. Based on this study, Malaysia can withstand this low seismic activity, overall joint acceleration, velocity and displacement

DNA resection in eukaryotes: deciding how to fix the break

DNA double-strand breaks are repaired by different mechanisms, including homologous recombination and nonhomologous end-joining. DNA-end resection, the first step in recombination, is a key step that contributes to the choice of DSB repair. Resection, an evolutionarily conserved process that generates single-stranded DNA, is linked to checkpoint activation and is critical for survival. Failure to regulate and execute this process results in defective recombination and can contribute to human disease. Here, I review recent findings on the mechanisms of resection in eukaryotes, from yeast to vertebrates, provide insights into the regulatory strategies that control it, and highlight the consequences of both its impairment and its deregulation