Development of a new quantum trajectory molecular dynamics framework.

An extension to the wave packet description of quantum plasmas is presented, where the wave packet can be elongated in arbitrary directions. A generalized Ewald summation is constructed for the wave packet models accounting for long-range Coulomb interactions and fermionic effects are approximated by purpose-built Pauli potentials, self-consistent with the wave packets used. We demonstrate its numerical implementation with good parallel support and close to linear scaling in particle number, used for comparisons with the more common wave packet employing isotropic states. Ground state and thermal properties are compared between the models with differences occurring primarily in the electronic subsystem. Especially, the electrical conductivity of dense hydrogen is investigated where a 15% increase in DC conductivity can be seen in our wave packet model compared with other models. This article is part of the theme issue 'Dynamic and transient processes in warm dense matter'.

Self-diffusion of a relativistic Lennard-Jones gas via semirelativistic molecular dynamics.

The capability for molecular dynamics simulations to treat relativistic dynamics is extended by the inclusion of relativistic kinetic energy. In particular, relativistic corrections to the diffusion coefficient are considered for an argon gas modeled with a Lennard-Jones interaction. Forces are transmitted instantaneously without being retarded, an approximation that is allowed due to the short-range nature of the Lennard-Jones interaction. At a mass density of 1.4g/cm^{3}, significant deviations from classical results are observed at temperatures above k_{B}T≈0.05mc^{2}, corresponding to an average thermal velocity of 32% of the speed of light. For temperatures approaching k_{B}T≈mc^{2}, the semirelativistic simulations agree with analytical results for hard spheres, which is seen to be a good approximation as far as diffusion effects are concerned.

Learning transport processes with machine intelligence.

Transport processes ruled by complex micro-physics and impractical to theoretical investigation may exhibit emergent behavior describable by mathematical expressions. Such information, while implicitly contained in the results of microscopic-scale numerical simulations close to first principles or experiments is not in a form suitable for macroscopic modelling. Here we present a machine learning approach that leverages such information to deploy micro-physics informed transport flux representations applicable to a continuum mechanics description. One issue with deep neural networks, arguably providing the most generic of such representations, is their noisiness which is shown to break the performance of numerical schemes. The matter is addressed and a methodology suitable for schemes characterised by second order convergence rate is presented. The capability of the methodology is demonstrated through an idealized study of the long standing problem of heat flux suppression relevant to fusion and cosmic plasmas. Symbolic representations, although potentially less generic, are straightforward to use in numerical schemes and theoretical analysis, and can be even more accurate as shown by the application to the same problem of an advanced symbolic regression tool. These results are a promising initial step to filling the gap between micro and macro in this important area of modeling.

Strong suppression of heat conduction in a laboratory replica of galaxy-cluster turbulent plasmas.

In conventional gases and plasmas, it is known that heat fluxes are proportional to temperature gradients, with collisions between particles mediating energy flow from hotter to colder regions and the coefficient of thermal conduction given by Spitzer's theory. However, this theory breaks down in magnetized, turbulent, weakly collisional plasmas, although modifications are difficult to predict from first principles due to the complex, multiscale nature of the problem. Understanding heat transport is important in astrophysical plasmas such as those in galaxy clusters, where observed temperature profiles are explicable only in the presence of a strong suppression of heat conduction compared to Spitzer's theory. To address this problem, we have created a replica of such a system in a laser laboratory experiment. Our data show a reduction of heat transport by two orders of magnitude or more, leading to large temperature variations on small spatial scales (as is seen in cluster plasmas).

Time-resolved turbulent dynamo in a laser plasma.

Understanding magnetic-field generation and amplification in turbulent plasma is essential to account for observations of magnetic fields in the universe. A theoretical framework attributing the origin and sustainment of these fields to the so-called fluctuation dynamo was recently validated by experiments on laser facilities in low-magnetic-Prandtl-number plasmas ([Formula: see text]). However, the same framework proposes that the fluctuation dynamo should operate differently when [Formula: see text], the regime relevant to many astrophysical environments such as the intracluster medium of galaxy clusters. This paper reports an experiment that creates a laboratory [Formula: see text] plasma dynamo. We provide a time-resolved characterization of the plasma's evolution, measuring temperatures, densities, flow velocities, and magnetic fields, which allows us to explore various stages of the fluctuation dynamo's operation on seed magnetic fields generated by the action of the Biermann-battery mechanism during the initial drive-laser target interaction. The magnetic energy in structures with characteristic scales close to the driving scale of the stochastic motions is found to increase by almost three orders of magnitude and saturate dynamically. It is shown that the initial growth of these fields occurs at a much greater rate than the turnover rate of the driving-scale stochastic motions. Our results point to the possibility that plasma turbulence produced by strong shear can generate fields more efficiently at the driving scale than anticipated by idealized magnetohydrodynamics (MHD) simulations of the nonhelical fluctuation dynamo; this finding could help explain the large-scale fields inferred from observations of astrophysical systems.

Vacuum intraoperative specimen mammography: A novel technique.

OBJECTIVE: Intraoperative specimen mammography (ISM) is a diffuse technique that allows surgeons to check specimens immediately after lumpectomy. Although the specimen is slightly compressed, the radiological image can be distorted by tissue overlap, and this may affect the evaluation of tumour borders, resulting in extension of the lumpectomy. As ISM may be less precise due to inadequate compression, a vacuum effect was applied to the specimen to increase the precision of margin detection. STUDY DESIGN: This study was conducted at St. Anna Hospital Breast Unit, Turin, Italy. Women who underwent lumpectomy for cancer were eligible for inclusion. Both standard ISM (sISM) and vacuum ISM (vISM) were performed. Eighteen specimens obtained after lumpectomy from 1 April 2018 to 31 April 2018 were scanned. sISM (two orthogonal projections) was performed. Next, the specimen was placed in a vacuum, and vISM was performed. The examination was completed with a second orthogonal projection after removal of the vacuum, replacement of the specimen and repositioning of the vacuum. Additional tissue was removed if the surgeon considered that excision was inadequate. Finally, the specimen was sent for definitive histopathological analysis, which is the gold standard for the assessment of surgical margins. Intraoperative histological margin assessment was not performed. The sISM and vISM images and final histopathology reports were compared. RESULTS: For sISM, specificity was 47 % [95 % confidence interval (CI) 25-70], sensitivity was 67 % (95 % CI 21-94), positive predictive value (PPV) was 20 % (95 % CI 6-51) and negative predictive value (NPV) was 88 % (95 % CI 53-98). For vISM, specificity was 100 % (95 % CI 80-100), sensitivity was 67 % (95 % CI 21-94), PPV was 100 % (95 % CI 34-100) and NPV was 94 % (95 % CI 72-99). CONCLUSION: These data suggest that the vacuum technique is feasible, cost-saving and yields results that are similar to those from frozen sections but without the limitations, such as prolonged operating time, high variability in sensitivity due to pathologists' abilities, risk of compromising the histological report, and unreliability for small lumps and ductal carcinoma in situ.

Dynamic X-ray diffraction observation of shocked solid iron up to 170 GPa.

Investigation of the iron phase diagram under high pressure and temperature is crucial for the determination of the composition of the cores of rocky planets and for better understanding the generation of planetary magnetic fields. Here we present X-ray diffraction results from laser-driven shock-compressed single-crystal and polycrystalline iron, indicating the presence of solid hexagonal close-packed iron up to pressure of at least 170 GPa along the principal Hugoniot, corresponding to a temperature of 4,150 K. This is confirmed by the agreement between the pressure obtained from the measurement of the iron volume in the sample and the inferred shock strength from velocimetry deductions. Results presented in this study are of the first importance regarding pure Fe phase diagram probed under dynamic compression and can be applied to study conditions that are relevant to Earth and super-Earth cores.

ß-thalassemia patients and gynecological approach: review and clinical experience.

Significant improvements in therapy and life expectancy of ß-thalassemia patients in last decades result in the need of commitment for gynecologists and obstetricians as the complexity of organ impairment needs a specific multidisciplinary approach. After a review of clinical manifestations of ß-thalassemia from a gynecologic point of view, we present the experience of a gynecologic center in treating ß-thalassemia patients from more than 20 years.

Developed turbulence and nonlinear amplification of magnetic fields in laboratory and astrophysical plasmas.

The visible matter in the universe is turbulent and magnetized. Turbulence in galaxy clusters is produced by mergers and by jets of the central galaxies and believed responsible for the amplification of magnetic fields. We report on experiments looking at the collision of two laser-produced plasma clouds, mimicking, in the laboratory, a cluster merger event. By measuring the spectrum of the density fluctuations, we infer developed, Kolmogorov-like turbulence. From spectral line broadening, we estimate a level of turbulence consistent with turbulent heating balancing radiative cooling, as it likely does in galaxy clusters. We show that the magnetic field is amplified by turbulent motions, reaching a nonlinear regime that is a precursor to turbulent dynamo. Thus, our experiment provides a promising platform for understanding the structure of turbulence and the amplification of magnetic fields in the universe.

Surgical scar endometriosis.

Endometriosis is a common disorder in females of reproductive age. Surgical scar endometrioma after cesarean section develops in 1-2% of patients, and usually presents as a tender and painful abdominal wall mass. The diagnosis is suggested by pre or perimenstrual pelvic pain and is often established only by histology. In this retrospective observational cohort study, we reviewed the medical records of five patients with a histopathological diagnosis of scar endometriosis. A scar mass was found on a previous Pfannenstiel incision in four patients and in a median cesarean section in one patient. The mean age at diagnosis (38.6 years, median 38) was older than reported elsewhere. A histological examination of the surgical specimen confirmed the diagnosis of endometriosis in all cases. During the follow-up period (mean 34.6 months), local recurrence (n = 1) and pelvic recurrence (n = 1) were treated surgically. Surgery is the treatment of choice for surgical scar endometriosis. Excision with histologically proven free surgical margins of 1 cm is mandatory to prevent recurrence. As scar endometriosis may be associated with pelvic localization, explorative abdominal laparoscopy may be indicated to exclude the intraperitoneal spread of the disease in symptomatic patients.

Association of large noncoding RNA HOTAIR expression and its downstream intergenic CpG island methylation with survival in breast cancer.

Large noncoding RNA HOTAIR, transcribed from the antisense strand of HOXC12, interacts with Polycomb Repressive Complex 2 (PRC2) in the regulation of gene activities. Recent work suggests that it may have effects on breast cancer progression and survival. We evaluated HOTAIR expression and the methylation status of its downstream intergenic CpG island in primary breast cancers, and examined associations of these factors with clinical and pathologic features and patient survival. HOTAIR expression and DNA methylation were analyzed in tissue from 348 primary breast cancers with quantitative RT-PCR and methylation-specific PCR, respectively. HOTAIR expression and methylation varied widely in the tissues. A positive correlation was found between DNA methylation and HOTAIR expression. Methylation was associated with unfavorable disease characteristics, whereas no significant associations were found between HOTAIR expression and clinical or pathologic features. In multivariate, but not in univariate, Cox proportional hazard regression models, patients with high HOTAIR expression had lower risks of relapse and mortality than those with low HOTAIR expression. These findings suggest that the intergenic DNA methylation may have important biologic relevance in regulating HOTAIR expression, and that HOTAIR expression may not be an independent prognostic marker in breast cancer, but needs further validation in independent studies.

Comparative merits of the memory function and dynamic local-field correction of the classical one-component plasma.

The complementarity of the liquid and plasma descriptions of the classical one-component plasma is explored by studying wave number and frequency dependent dynamical quantities: the dynamical structure factor (DSF) and the dynamic local field correction (LFC). Accurate molecular dynamics (MD) simulations are used to validate and test models of the DSF and LFC. Our simulations, which span the entire fluid regime (Γ=0.1-175), show that the DSF is very well represented by a simple and well known memory function model of generalized hydrodynamics. On the other hand, the LFC, which we have computed using MD for the first time, is not well described by existing models.

Density fluctuations in the Yukawa one-component plasma: an accurate model for the dynamical structure factor.

Using numerical simulations, we investigate the equilibrium dynamics of a single-component fluid with Yukawa interaction potential. We show that, for a wide range of densities and temperatures, the dynamics of the system are in striking agreement with a simple model of generalized hydrodynamics. Since the Yukawa potential can describe the ion-ion interactions in a plasma, our results have significant applicability for both analyzing and interpreting the results of x-ray scattering data from high-power lasers and fourth-generation light sources.

Extent of validity of the hydrodynamic description of ions in dense plasmas.

We show that the hydrodynamic description can be applied to modeling the ionic response in dense plasmas for a wide range of length scales that are experimentally accessible. Using numerical simulations for the Yukawa model, we find that the maximum wave number k(max) at which the hydrodynamic description applies is independent of the coupling strength, given by k(max)λ(s)≃0.43, where λ(s) is the ionic screening length. Our results show that the hydrodynamic description can be used for interpreting x-ray scattering data from fourth generation light sources and high power lasers. In addition, our investigation sheds new light on how the domain of validity of the hydrodynamic description depends on both the microscopic properties and the thermodynamic state of fluids in general.

A case of leiomyoadenomatoid tumour of uterine serosa: speculations about differential diagnosis.

Adenomatoid tumour is a benign rare lesion of the female genital tract, localised in the wall of fallopian tubes or beneath the uterine serosa. It is often accompanied by smooth muscle proliferation, obscuring the presence of adenomatoid tumour, resulting in misdiagnosis of cellular leiomyoma.Here, a case of uterine serosal adenomatoid tumour associated with multiple leiomyomas and pelvic endometriosis in a 44-year-old woman who underwent surgical removal for uterine bleeding and abdominal pain is presented.