The effect of Hus1 on ionizing radiation sensitivity is associated with homologous recombination repair but is independent of non-homologous end-joining

Mammalian Hus1 plays an important role in maintaining genomic integrity. Cells lacking mouse Hus1 are hypersensitive to DNA damage inducers including UV and camptothecin (CPT). By using clonogenic assay, we show here that Hus1 deficient mouse cells are hypersensitive to ionizing radiation (IR) compared with their Hus1-positive counterparts. However, these cells show similar induction levels and similar rejoining rates of DNA double strand breaks (DSBs) following IR, indicating that the effect of Hus1 on cell radiosensitivity is independent of non-homologous end-joining (NHEJ). By combining an I-SceI-induced-DNA DSBs system and a siRNA approach, we also show that knocking down Hus1 decreases the efficiency of homologous recombination repair (HRR), which is associated with the cellular sensitivity to IR-induced killing. Together, these results indicate that the role of Hus1 affecting the sensitivity of cells to IR-induced killing is independent of NHEJ but might be linked to HRR

Numerical simulation of long wave runup for breaking and nonbreaking waves

Tsunamis produce a wealth of quantitative data that can be used to improve tsunami hazard awareness and to increase the preparedness of the population at risk. These data also allow for a performance evaluation of the coastal infrastructure and observations of sediment transport, erosion, and deposition. The interaction of the tsunami with coastal infrastructures and with the movable sediment bed is a three-dimensional process. Therefore, for runup and inundation prediction, three-dimensional numerical models must be employed. In this study, we have employed Smoothed Particle Hydrodynamics (SPH) to simulate tsunami runup on idealized geometries for the validation and exploration of three-dimensional flow structures in tsunamis. We make use of the canonical experiments for long-wave runup for breaking and nonbreaking waves. The results of our study prove that SPH is able to reproduce the runup of long waves for different initial and geometric conditions. We have also investigated the applicability and the effectiveness of different viscous terms that are available in the SPH literature. Additionally, a new breaking criterion based on numerical experiments is introduced, and its similarities and differences with existing criteria are discussed

Need telomere maintenance? Call 911

"Natura non facit saltum" (nature makes no leap) the Latins used to say, meaning that nature does not like discontinuities. Cells make no exception and indeed any discontinuity in the DNA double helix is promptly detected, triggering an alteration of cell proliferation and an attempt to repair. Yet, linear chromosomes bear DNA ends that are compatible with normal cell proliferation and they escape, under normal conditions, any repair. How telomeres, the chromosomes tips, achieve that is not fully understood. We recently observed that the Rad9/Hus1/Rad1 (911) complex, previously known for its functions in DNA metabolism and DNA damage responses, is constitutively associated with telomeres and plays an important role in their maintenance. Here, we summarize the available data and discuss the potential mechanisms of 911 action at telomeres

Exact solution of a model of qubit dephasing due to telegraph noise

We present a general and exact formalism for finding the evolution of a quantum system subject to external telegraph noise. The various qubit decoherence rates are determined by the eigenvalues of a transfer matrix. The formalism can be applied to a qubit subject to an arbitrary combination of dephasing and relaxational telegraph noise, in contrast to existing non-perturbative methods that treat only one or the other of these limits. We present 3 applications: 1) We obtain the full qubit dynamics on time scales short compared with the enviromental correlation times. In the strong coupling cases this reveals unexpected oscillations and induced magnetization components; 2) We find in strong coupling case strong violations of the widely used relation 1/T$_2$ = 1/2T$_1$ + 1/T$_{\phi}$, which is a result of perturbation theory; 3) We discuss the effects of bang-bang and spin-echo controls of the qubit dynamics in general settings of the telegraph noises. %The result shows that these methods are not very effective in %reducing decoherence arising from a single telegraph noise. Finally, we discuss the extension of the method to the cases of many telegraph noise sources and multiple qubits. The method still works when white noise is also present.Comment: 7 pages, 6 figures, revised and extende

Quantum Friction in Nanomechanical Oscillators at Millikelvin Temperatures

We report low-temperature measurements of dissipation in megahertz-range, suspended, single-crystal nanomechanical oscillators. At millikelvin temperatures, both dissipation (inverse quality factor) and shift in the resonance frequency display reproducible features, similar to those observed in sound attenuation experiments in disordered glasses and consistent with measurements in larger micromechanical oscillators fabricated from single-crystal silicon. Dissipation in our single-crystal nanomechanical structures is dominated by internal quantum friction due to an estimated number of roughly 50 two-level systems, which represent both dangling bonds on the surface and bulk defects.Comment: 5 pages, two-column format. Related papers available at http://nano.bu.ed

Eye of the Beholder: The individual and dyadic contributions of empathic accuracy and perceived empathic effort to relationship satisfaction

This study examined links between two distinct facets of empathy – empathic accuracy and perceived empathic effort – and one’s own and one’s partner’s relationship satisfaction. Using a video recall procedure, participants (N = 156 couples in committed relationships) reported on their own emotions and their perceptions of partners’ emotions and partners’ empathic intentions during moments of high affect in laboratory-based discussions of upsetting events. Partners’ data were correlated as a measure of how accurately they were able to read what the other was feeling and to what degree they felt the other was trying to be empathic at those moments. The perception of empathic effort by one’s partner was more strongly linked with both men’s and women’s relationship satisfaction than empathic accuracy. Men’s relationship satisfaction was related to the ability to read their partners’ positive emotions accurately, whereas women’s relationship satisfaction was related to their partners’ ability to read women’s negative emotions accurately. Women’s ability to read their husbands’ negative emotions was positively linked to both men’s and women’s relationship satisfaction. Findings suggest that the perception of a partner’s empathic effort – as distinct from empathic accuracy – is uniquely informative in understanding how partners may derive relationship satisfaction from empathic processes. When working with couples in treatment, heightening partners’ perceptions of each other’s empathic effort, and helping partners learn to demonstrate effort, may represent particularly powerful opportunities for improving satisfaction in relationships

Eye of the Beholder: The individual and dyadic contributions of empathic accuracy and perceived empathic effort to relationship satisfaction

This study examined links between two distinct facets of empathy – empathic accuracy and perceived empathic effort – and one’s own and one’s partner’s relationship satisfaction. Using a video recall procedure, participants (N = 156 couples in committed relationships) reported on their own emotions and their perceptions of partners’ emotions and partners’ empathic intentions during moments of high affect in laboratory-based discussions of upsetting events. Partners’ data were correlated as a measure of how accurately they were able to read what the other was feeling and to what degree they felt the other was trying to be empathic at those moments. The perception of empathic effort by one’s partner was more strongly linked with both men’s and women’s relationship satisfaction than empathic accuracy. Men’s relationship satisfaction was related to the ability to read their partners’ positive emotions accurately, whereas women’s relationship satisfaction was related to their partners’ ability to read women’s negative emotions accurately. Women’s ability to read their husbands’ negative emotions was positively linked to both men’s and women’s relationship satisfaction. Findings suggest that the perception of a partner’s empathic effort – as distinct from empathic accuracy – is uniquely informative in understanding how partners may derive relationship satisfaction from empathic processes. When working with couples in treatment, heightening partners’ perceptions of each other’s empathic effort, and helping partners learn to demonstrate effort, may represent particularly powerful opportunities for improving satisfaction in relationships