Solid-Density Ion Temperature from Redshifted and Double-Peaked Stark Line Shapes.

Heß spectral line shapes are important for diagnosing temperature and density in many dense plasmas. This work presents Heß line shapes measured with high spectral resolution from solid-density plasmas with minimized gradients. The line shapes show hallmark features of Stark broadening, including quantifiable redshifts and double-peaked structure with a significant dip between the peaks; these features are compared to models through a Markov chain Monte Carlo framework. Line shape theory using the dipole approximation can fit the width and peak separation of measured line shapes, but it cannot resolve an ambiguity between electron density n_{e} and ion temperature T_{i}, since both parameters influence the strength of quasistatic ion microfields. Here a line shape model employing a full Coulomb interaction for the electron broadening computes self-consistent line widths and redshifts through the monopole term; redshifts have different dependence on plasma parameters and thus resolve the n_{e}-T_{i} ambiguity. The measured line shapes indicate densities that are 80-100% of solid, identifying a regime of highly ionized but well-tamped plasma. This analysis also provides the first strong evidence that dense ions and electrons are not in thermal equilibrium, despite equilibration times much shorter than the duration of x-ray emission; cooler ions may arise from nonclassical thermalization rates or anomalous energy transport. The experimental platform and diagnostic technique constitute a promising new approach for studying ion-electron equilibration in dense plasmas.

All-Order Full-Coulomb Quantum Spectral Line-Shape Calculations.

Understanding how atoms interact with hot dense matter is essential for astrophysical and laboratory plasmas. Interactions in high-density plasmas broaden spectral lines, providing a rare window into interactions that govern, for example, radiation transport in stars. However, up to now, spectral line-shape theories employed at least one of three common approximations: second-order Taylor treatment of broadening operator, dipole-only interactions between atom and plasma, and classical treatment of perturbing electrons. In this Letter, we remove all three approximations simultaneously for the first time and test the importance for two applications: neutral hydrogen and highly ionized magnesium and oxygen. We found 15%-50% change in the spectral line widths, which are sufficient to impact applications including white-dwarf mass determination, stellar-opacity research, and laboratory plasma diagnostics.

Effect of Electron Capture on Spectral Line Broadening in Hot Dense Plasmas.

Accurate calculation of spectral line broadening is important for many hot, dense plasma applications. However, calculated line widths have significantly underestimated measured widths for Δn=0 lines of Li-like ions, which is known as the isolated-line problem. In this Letter, scrutinization of the line-width derivation reveals that the commonly used expression neglects a potentially important contribution from electron-capture. Line-width calculations including this process are performed with two independent codes, both of which removed the discrepancies at temperatures below 10 eV. The revised calculations also suggest the remaining discrepancy scales more strongly with electron temperature than the atomic number as was previously suggested.

Usefulness of a circumferential wound retractor in emergency colorectal surgery as a preventive measure for surgical site infection. Alexis O-Ring® and emergency surgery. / Utilidad del separador circunferencial para herida en cirugía colorrectal de urgencia como medida preventiva para infección del sitio quirúrgico. El Alexis O-Ring® y la cirugía de urgencia.

INTRODUCTION AND AIMS: More than 20% of healthcare-associated infections correspond to those at surgical sites, and there is a higher incidence of infections in colorectal surgery due to the associated bacterial load. Surgical wound protectors are designed to prevent contamination and mechanical trauma. Our aim was to demonstrate the usefulness of a circumferential wound retractor/protector for the prevention of surgical site infections (SSIs) in emergency colorectal surgery. METHODS: Forty-one patients that underwent emergency open surgery at a tertiary care hospital were randomized into 2 groups: 20 cases without the retractor (group A) and 21 cases with the retractor (group B). Subjects were assigned to a group in a 1:1 randomization allocation ratio. The chi-square and Fisher's exact tests were employed for the quantitative variables, and the statistical analysis was performed using the IBM Statistical Package for the Social Sciences software for Mac, version 16.0 (IBM SPSS Inc., Chicago, IL, USA). RESULTS: The SSI rate was 17%. Six group A patients developed SSI versus one group B patient. The use of a circumferential wound retractor/protector was statistically significant for the prevention of surgical wound infections, with a P=.031 and an OR of 8.5. In addition, preoperative blood glucose levels below 200mg/dl provided a 3.2-times higher protective effect, compared with glucose levels above 200mg/dl. CONCLUSIONS: In the present prospective randomized pilot study, the use of the circumferential wound retractor/protector significantly decreased the likelihood of SSI in emergency colorectal surgery.

[Trichobezoar: unusual diagnosis. Report of 3 cases]. / Tricobezoar: diagnostico inusual. Reporte de 3 casos.

We report 3 cases of gastric trichobezoar, recorded in the last 10 years in our Hospital. All the cases presented abdominal pain and tumor, as well as upper obstructive symptoms. The 3 cases were surgically treated with satisfactory evolution. The clinical has to consider this diagnosis taking into account the data summarized here. Surgery is a successful treatment for these cases. The literature on bezoars is reviewed.