First-principles analysis of spin-disorder resistivity of Fe and Ni

Spin-disorder resistivity of Fe and Ni and its temperature dependence are analyzed using noncollinear density functional calculations within the supercell method. Different models of thermal spin disorder are considered, including the mean-field approximation and the nearest-neighbor Heisenberg model. Spin-disorder resistivity is found to depend weakly on magnetic short-range order. If the local moments are kept frozen at their zero-temperature values, very good agreement with experiment is obtained for Fe, but for Ni the resistivity at elevated temperatures is significantly overestimated. Agreement with experiment for Fe is improved if the local moments are iterated to self-consistency. The overestimation of the resistivity for paramagnetic Ni is attributed to the reduction of the local moments down to 0.35 Bohr magnetons. Overall, the results suggest that low-energy spin fluctuations in Fe and Ni are better viewed as classical rotations of local moments rather than quantized spin fluctuations that would require an (S+1)/S correction.Comment: 10 pages (RevTeX), 6 eps figure

Simulation Supported Estimation of End-to-End Transmission Parameters in Non-Viral Gene Delivery

Communications, in general, involve delivery of information from a source to a sink. At nano-scale, an example of a man-made communications involving interfacing with biological systems at intra-cellular level is non-viral gene delivery. From a telecommunications engineering perspective, important end-to-end parameters of such a system are: the endto- end delay, system capacity, and packet loss rate. There are neither known methods to estimate those parameters theoretically nor they are ready available from standard measurements. The paper provides estimates for those parameters based on the simulation of non-viral gene delivery system based on the queuing theory. The simulator used has been validated through the series of in-vitro laboratory experiments

Morphological predictors of sleep apnoea severity

Background: Obstructive sleep apnoea (OSA) does not always depend on obesity but on a certain morphological configuration. The study objective was to verify a hypothesis about a relation between anthropometric features and OSA occurrence and severity. Materials and methods: The study involved 138 patients, who had reported in Department and Clinic of Otolaryngology, Warsaw Medical University, due to suspected OSA. Each patient underwent morphological evaluation according to visual analogue scales. The assessment involved nasal septum morphology evaluation according to a 4-grade scale, palate morphology evaluation according to the 4-grade Friedman scale, whereas the facial profile, oropharyngeal isthmus, and the shape of the nasopharynx were assessed according to our own 3-grade scale. Results: Statistical analysis confirmed the high concordance of the basic polysomnographic parameters with the Friedman scale and the shape of the oropharyngeal isthmus. Conclusions: 1. The modified Mallampati score as well as evaluation of the shape of the oropharyngeal isthmus demonstrated high concordance with the basic polysomnographic parameters. 2. The neck circumference is a significant predictor of the apnoea-hypopnoea index value in males suffering from the OSA syndrom

Management of metastases in regional lymph nodes in melanoma patients in 2019

For several years, the standard of management in case of melanoma metastases in regional lymph nodes was to remove an adequate node group. In 2016 and 2017, the results of two large, well-designed clinical trials with randomization and a control group were published, which changed the current management. The authors of DeCOG-STL study came to the conclusion that withdrawal from completion lymph node dissection in the case of a small melanoma metastasis in a sentinel lymph node (metastasis diameter ≤1 mm) is not associated with a worsening of the 3-years’ survival chance (both in terms of overall survival and survival time to the occurrence of distant metastases). The results of MSTL-II study were similar. Based on the results of both studies presented above, in 2018 the American Society of Clinical Oncology (ASCO) and the Society of Surgical Oncology (SSO) presented joint recommendations concerning, among others, current indications for completion lymph node dissection in SNB positive melanoma patients

Radiotherapy or axillary lymph node dissection in breast cancer patients with positive sentinel lymph nodes?

Over the years the surgical management of localized breast cancer has become less aggressive. Complete resection of the primary tumour with negative margins replaced mastectomy and is currently a standard of care in a vast ma­jority of women with early breast cancer. Also, an introduction of sentinel lymph node biopsy allowed for giving up axillary lymph node dissection in the patients with pathologically negative sentinel nodes. This development has led to a decrease of morbidity such as lymphedema. However, the standard management of axilla in the patients with positive sentinel lymph nodes remains controversial. Recent studies demonstrated that in the patients with 1 or 2 positive sentinel lymph nodes who undergo breast conserving surgery followed by conventionally fractionated whole-breast radiotherapy, a completion axillary lymph node dissection can be avoided. Furthermore, evidence from three two-phase non-inferiority studies comparing radiotherapy with complete lymph node dissection did not show any significant differences in either overall and disease-free survival, or local control and decrease of the percentage of patients with local adverse effects in radiotherapy arms. However, there are several methodological drawbacks and clinical limitations of these studies, which prevent from general omission of completion axillary lymph node dissection in breast cancer patients with positive sentinel lymph nodes. The debate held during V Annual Conference of Nowotwory Journal of Oncology and resulting article discusses the optimal management of axilla in this population

Calculations of spin-disorder resistivity from first principles

Spin-disorder resistivity of Fe and Ni is studied using the noncollinear density functional theory. The Landauer conductance is averaged over random disorder configurations and fitted to Ohm's law. The distribution function is approximated by the mean-field theory. The dependence of spin-disorder resistivity on magnetization in Fe is found to be in excellent agreement with the results for the isotropic s-d model. In the fully disordered state, spin-disorder resistivity for Fe is close to experiment, while for fcc Ni it exceeds the experimental value by a factor of 2.3. This result indicates strong magnetic short-range order in Ni at the Curie temperature.Comment: 3 pages, 3 figure

Measurements of Cold Nuclear Matter Effects on J/psi in the PHENIX Experiment via Deuteron-Gold Collisions

A new calculation of R_{dAu} has been performed using the 2003 d+Au data and the higher-statistics 2005 p+p data. These nuclear modification factors are compared to calculations using nuclear-modified PDFs and a J/psi breakup cross section is extracted. These values are then used to project the cold nuclear matter effects in Au+Au collisions. Additionally, a more data-driven projection is performed.Comment: 4 pages, 6 figures, proceedings for Quark Matter 200