Melting of genomic DNA: predictive modeling by nonlinear lattice dynamics

The melting behavior of long, heterogeneous DNA chains is examined within the framework of the nonlinear lattice dynamics based Peyrard-Bishop-Dauxois (PBD) model. Data for the pBR322 plasmid and the complete T7 phage have been used to obtain model fits and determine parameter dependence on salt content. Melting curves predicted for the complete fd phage and the Y1 and Y2 fragments of the $\phi$X174 phage without any adjustable parameters are in good agreement with experiment. The calculated probabilities for single base-pair opening are consistent with values obtained from imino proton exchange experiments.Comment: 5 pages, 4 figures, to appear in Phys. Rev.

Required precision of mass and half-life measurements for r-process nuclei planned at future RI-beam facilities

In order to understand the r-process nucleosynthesis, we suggest precision required for mass and beta-decay half-life measurements planned at future RI-beam facilities. To satisfy a simple requirement that we put on nuclear model predictions, it is concluded that the detectors for the mass measurements must have a precision of 1sigma ~< 250 keV, and that the detectors for the half-life measurements demand a precision of 1sigma ~< 0.15 ms. Both the above precisions are required at the neutron richness of A/Z = 3.0 at the N=82 shell closure and A/Z = 2.9 at the N=50 shell closure. For the doubly magic nuclide 78Ni, a precision of 1sigma ~< 300 keV and 1sigma ~< 5 ms are required, respectively, for mass and half-life measurements. This analysis aims to provide a first rough guide for ongoing detector developments.Comment: 8 pages, 2 figures. in Proceedings of Int. conf. The Future Astronuclear Physics, From microscopic puzzles to macroscopic nightmares, Eds. H.M.J. Boffin et al., EAS Publication Series, EDP Sciences, in press (2004

`Hidden' Symmetries of Higher Dimensional Rotating Black Holes

We demonstrate that the rotating black holes in an arbitrary number of dimensions and without any restrictions on their rotation parameters possess the same `hidden' symmetry as the 4-dimensional Kerr metric. Namely, besides the spacetime symmetries generated by the Killing vectors they also admit the (antisymmetric) Killing-Yano and symmetric Killing tensors.Comment: 4 pages, slightly extended introductio

Oncologic outcomes following surgical management of clinical stage II sex cord stromal tumors

Objective To investigate the clinical history of patients with clinical stage II sex cord stromal tumors who underwent RPLND at our institution. Methods Our prospectively maintained testicular cancer database was queried to identify patients who presented with or developed clinical stage II sex cord stromal tumors and underwent RPLND at our institution between 1980 and 2018. Demographic, clinical and pathological characteristics were reviewed. Kaplan-Meier curves were graphed to assess recurrence-free and overall survival. Results Fourteen patients were included in the study with a median age of 44.2 years. Four patients presented with clinical stage II disease and 10 patients developed metastatic disease during follow-up of initial clinical stage I disease with a median time to metastasis of 2.7 years (range: 0.4-19.5 years). Of the 10 patients with orchiectomy pathology data available, all patients had at least 1 risk factor on testis pathology (mean: 2.9 risk factors). Nine patients received treatment prior to referral to our institution. All patients recurred post-RPLND at Indiana University. Median recurrence-free survival was 9.8 months. Twelve patients died of disease with a median overall survival of 14.4 months. Conclusions Metastatic sex cord stromal tumors are rare and are more resistant to standard treatment modalities than metastatic germ cell tumors. Patients presenting with sex cord stromal tumors should consider prophylactic primary RPLND in the setting of one or more pathological predictor of malignancy

Short-lived radioisotopes in meteorites from Galactic-scale correlated star formation

Meteoritic evidence shows that the Solar system at birth contained significant quantities of short-lived radioisotopes (SLRs) such as 60Fe and 26Al (with half-lives of 2.6 and 0.7 Myr, respectively) produced in supernova (SN) explosions and in the Wolf–Rayet winds that precede them. Proposed explanations for the high SLR abundance include formation of the Sun in an SN-triggered collapse or in a giant molecular cloud (GMC) that was massive enough to survive multiple SNe and confine their ejecta. However, the former scenario is possible only if the Sun is a rare outlier among massive stars, while the latter appears to be inconsistent with the observation that 26Al is distributed with a scale height significantly larger than GMCs. In this paper, we present a high-resolution chemohydrodynamical simulation of the entire Milky-Way Galaxy, including stochastic star formation, H II regions, SNe, and element injection, that allows us to measure for the distribution of 60Fe/56Fe and 26Al/27Al ratios over all stars in the Galaxy. We show that the Solar system’s abundance ratios are well within the normal range, but that SLRs originate neither from triggering nor from confinement in long-lived clouds as previously conjectured. Instead, we find that SLRs are abundant in newborn stars because star formation is correlated on galactic scales, so that ejecta preferentially enrich atomic gas that will subsequently be accreted onto existing GMCs or will form new ones. Thus, new generations of stars preferentially form in patches of the Galaxy contaminated by previous generations of stellar winds and SNe.YF and MRK acknowledge support from the Australian Government through the Australian Research Council’s Discovery Projects funding scheme (project DP160100695)

Intrinsic electric field effects on few-particle interactions in coupled GaN quantum dots

We study the multi-exciton optical spectrum of vertically coupled GaN/AlN quantum dots with a realistic three-dimensional direct-diagonalization approach for the description of few-particle Coulomb-correlated states. We present a detailed analysis of the fundamental properties of few-particle/exciton interactions peculiar of nitride materials. The giant intrinsic electric fields and the high electron/hole effective masses give rise to different effects compared to GaAs-based quantum dots: intrinsic exciton-exciton coupling, non-molecular character of coupled dot exciton wavefunction, strong dependence of the oscillator strength on the dot height, large ground state energy shift for dots separated by different barriers. Some of these effects make GaN/AlN quantum dots interesting candidates in quantum information processing.Comment: 23 pages, 8 figures, 1 tabl

Electronic stress tensor analysis of hydrogenated palladium clusters

We study the chemical bonds of small palladium clusters Pd_n (n=2-9) saturated by hydrogen atoms using electronic stress tensor. Our calculation includes bond orders which are recently proposed based on the stress tensor. It is shown that our bond orders can classify the different types of chemical bonds in those clusters. In particular, we discuss Pd-H bonds associated with the H atoms with high coordination numbers and the difference of H-H bonds in the different Pd clusters from viewpoint of the electronic stress tensor. The notion of "pseudo-spindle structure" is proposed as the region between two atoms where the largest eigenvalue of the electronic stress tensor is negative and corresponding eigenvectors forming a pattern which connects them.Comment: 22 pages, 13 figures, published online, Theoretical Chemistry Account

Chemical Compositions of Pine Resin, Rosin and Turpentine Oil From West Java

This study was conducted to identify chemical composition of merkus pine resin, rosin and turpentine oil. Initially, pine resin was separated into neutral and acidic fractions with an aqueous 4% sodium hydroxide solution. After methylation, the fraction containing turpentine oil and rosin were analyzed by gas chromatography (GC), and gas chromatograph mass spectrometry (GC-MS), respectively. The neutral fraction of pine resin and turpentine oil mainly consisted of a-pinene, D-3-carene and b-pinene. Based on mass spectral comparison, the major constituents of the acidic fraction and rosin were identified as sandaracopimaric acid, isopimaric acid, palustric acid, dehydroabietic acid, abietic acid, neoabietic acid, and merkusic acid. The major component of the acidic fractions was palustric acid, while that of rosin was abietic acid. Using TC (tough column) 1 and TC 5 columns, levopimaric acid could not be separated from rosin or acidic fraction of pine resin of Indonesian Pinus merkusii