Absolute Equation-of-State Measurement for Polystyrene from 25 to 60 Mbar Using a Spherically Converging Shock Wave.

We have developed an experimental platform for the National Ignition Facility that uses spherically converging shock waves for absolute equation-of-state (EOS) measurements along the principal Hugoniot. In this Letter, we present one indirect-drive implosion experiment with a polystyrene sample that employs radiographic compression measurements over a range of shock pressures reaching up to 60 Mbar (6 TPa). This significantly exceeds previously published results obtained on the Nova laser [R. Cauble et al., Phys. Rev. Lett. 80, 1248 (1998)PRLTAO0031-900710.1103/PhysRevLett.80.1248] at a strongly improved precision, allowing us to discriminate between different EOS models. We find excellent agreement with Kohn-Sham density-functional-theory-based molecular dynamics simulations.

Effect of V/III ratio on the structural and optical properties of self-catalysed GaAs nanowires.

The performance of GaAs nanowire (NW) devices depends critically on the presence of crystallographic defects in the NWs such as twinning planes and stacking faults, and considerable effort has been devoted to understanding and preventing the occurrence of these. For self-catalysed GaAs NWs grown by molecular beam epitaxy (MBE) in particular, there are in addition other types of defects that may be just as important for NW-based optoelectronic devices. These are the point defects such as the As vacancy and the Ga antisite occurring due to the inherently Ga-rich conditions of the self-catalysed growth. Here we demonstrate experimentally the effects of these point defects on the optical properties of GaAs/AlGaAs core-shell NWs grown by self-catalysed MBE. The present results enable insight into the role of the point defects both on their own and in conjunction with crystallographic planar defects.

Bursts of Terahertz Radiation from Large-Scale Plasmas Irradiated by Relativistic Picosecond Laser Pulses.

Powerful terahertz (THz) radiation is observed from large-scale underdense preplasmas in front of a solid target irradiated obliquely with picosecond relativistic intense laser pulses. The radiation covers an extremely broad spectrum with about 70% of its energy located in the high frequency regime over 10 THz. The pulse energy of the radiation is found to be above 100 µJ per steradian in the laser specular direction at an optimal preplasma scale length around 40-50 µm. Particle-in-cell simulations indicate that the radiation is mainly produced by linear mode conversion from electron plasma waves, which are excited successively via stimulated Raman scattering instability and self-modulated laser wakefields during the laser propagation in the preplasma. This radiation can be used not only as a powerful source for applications, but also as a unique diagnostic of parametric instabilities of laser propagation in plasmas.

Patient perspectives on infection prevention and control in cancer care: a survey of knowledge and attitudes among persons with cancer and their next of kin.

BACKGROUND: With the growing prevalence of antimicrobial resistance, there may be a need to strengthen infection prevention and control (IPC) measures in cancer care. When developing clinical guidelines, it is important to incorporate patient perspectives. AIM: To determine the knowledge of, and attitudes towards, IPC among persons with cancer and their next of kin in Norway. METHODS: Through discussions in expert panels and a pilot study, a survey was developed consisting of 13 knowledge statements to be judged true/false and 40 attitude items to be judged using a Likert scale and was sent to a panel of people with cancer experience on August 22nd, 2023. The mean correct responses and attitude scores were reported. FINDINGS: Of 551 respondents, the mean correct response to IPC-related knowledge questions was 79% (95% confidence interval: 78-80). Respondents were most knowledgeable about hand hygiene (99%, 546/551), but least knowledgeable about its role in preventing antibiotic resistance (41%, 225/551). Strong support was noted for IPC, especially within the patient responsibilities theme, with a mean score of 4.83. However, there was a notable reluctance towards some selected intrusive IPC measures, such as reducing contact with close relations. CONCLUSION: This survey revealed a high level of knowledge and attitudes that support the importance of IPC among persons with cancer in Norway and their next of kin. We recommend including patient perspectives in future development of IPC guidelines.

Quantifying electron temperature distributions from time-integrated x-ray emission spectra.

K-shell x-ray emission spectroscopy is a standard tool used to diagnose the plasma conditions created in high-energy-density physics experiments. In the simplest approach, the emissivity-weighted average temperature of the plasma can be extracted by fitting an emission spectrum to a single temperature condition. It is known, however, that a range of plasma conditions can contribute to the measured spectra due to a combination of the evolution of the sample and spatial gradients. In this work, we define a parameterized model of the temperature distribution and use Markov Chain Monte Carlo sampling of the input parameters, yielding uncertainties in the fit parameters to assess the uniqueness of the inferred temperature distribution. We present the analysis of time-integrated S and Fe x-ray spectroscopic data from the Orion laser facility and demonstrate that while fitting each spectral region to a single temperature yields two different temperatures, both spectra can be fit simultaneously with a single temperature distribution. We find that fitting both spectral regions together requires a maximum temperature of 1310-70 +90 eV with significant contributions from temperatures down to 200 eV.

The Fusarium mycotoxin, 2-Amino-14,16-dimethyloctadecan-3-ol (AOD) induces vacuolization in HepG2 cells.

The mycotoxin 2-Amino-14,16-dimethyloctadecan-3-ol (AOD) has been isolated from cultures of the fungus Fusarium avenaceum, one of the most prevalent Fusarium species. AOD is an analogue of sphinganine and 1-deoxysphinganine, important intermediates in the de novo biosynthesis of cellular sphingolipids. Here we studied cellular effects of AOD using the human liver cell line HepG2 as a model system. AOD (10 µM) induced a transient accumulation of vacuoles in the cells. The effect was observed at non-cytotoxic concentrations and was not linked to cell death processes. Proteomic analyses indicated that protein degradation and/or vesicular transport may be a target for AOD. Further studies revealed that AOD had only minor effects on the initiation rate of macropinocytosis and autophagy. However, the AOD-induced vacuoles were lysosomal-associated membrane protein-1 (LAMP-1) positive, suggesting that they most likely originate from lysosomes or late endosomes. Accordingly, both endosomal and autophagic protein degradation were inhibited. Further studies revealed that treatment with concanamycin A or chloroquine completely blocked the AOD-induced vacuolization, suggesting that the vacuolization is dependent of acidic lysosomes. Overall, the results strongly suggest that the increased vacuolization is due to an accumulation of AOD in lysosomes or late endosomes thereby disturbing the later stages of the endolysosomal process.

Mountain birch under multiple stressors--heavy metal-resistant populations co-resistant to biotic stress but maladapted to abiotic stress.

Stress adaptations often include a trade-off of weakened performance in nonlocal conditions, resulting in divergent selection, and potentially, genetic differentiation and evolutionary adaptation. Results of a two-phase (greenhouse and field) common garden experiment demonstrated adaptation of mountain birch (Betula pubescens subsp. czerepanovii) populations from industrially polluted areas of the Kola Peninsula, north-western Russia, to heavy metals (HM), whereas no adaptations to wind or drought stress were detected in populations from wind-exposed sites. HM-adapted seedlings were maladapted to drought but less palatable (co-resistant) to insect herbivores, even under background HM concentrations. The absence of adaptations to harsh microclimate and the generally high adaptive potential of mountain birch, a critical forest forming tree in subarctic Europe, need to be accounted for in models predicting consequences of human-driven environmental changes, including the projected climate change.

Changes in cerebral cortex size are governed by fibroblast growth factor during embryogenesis.

We show that fibroblast growth factor 2 (FGF2) and FGF receptors are transiently expressed by cells of the pseudostratified ventricular epithelium (PVE) during early neurogenesis. A single microinjection of FGF2 into cerebral ventricles of rat embryos at E15.5 increased the volume and total number of neurons in the adult cerebral cortex by 18% and 87%, respectively. Microinjection of FGF2 by the end of neurogenesis, at E20.5, selectively increased the number of glia. Mice lacking the FGF2 gene had fewer cortical neurons and glia at maturity. BrdU studies in FGF2-microinjected and FGF2-null animals suggested that FGF2 increases the proportion of dividing cells in the PVE without affecting the cell-cycle length. Thus, FGF2 increases the number of rounds of division of cortical progenitors.

Roles of Fas and Fas ligand during mammary gland remodeling.

Mammary involution is associated with degeneration of the alveolar structure and programmed cell death of mammary epithelial cells. In this study, we evaluated the expression of Fas and Fas ligand (FasL) in the mammary gland tissue and their possible role in the induction of apoptosis of mammary cells. FasL-positive cells were observed in normal mammary epithelium from pregnant and lactating mice, but not in nonpregnant/virgin mouse mammary tissue. Fas expression was observed in epithelial and stromal cells in nonpregnant mice but was absent during pregnancy. At day 1 after weaning, high levels of both Fas and FasL proteins and caspase 3 were observed and coincided with the appearance of apoptotic cells in ducts and glands. During the same period, no apoptotic cells were found in the Fas-deficient (MRL/lpr) and FasL-deficient (C3H/gld) mice. Increase in Fas and FasL protein was demonstrated in human (MCF10A) and mouse (HC-11) mammary epithelial cells after incubation in hormone-deprived media, before apoptosis was detected. These results suggest that the Fas-FasL interaction plays an important role in the normal remodeling of mammary tissue. Furthermore, this autocrine induction of apoptosis may prevent accumulation of cells with mutations and subsequent neoplastic development. Failure of the Fas/FasL signal could contribute to tumor development.

Average-atom treatment of relaxation time in x-ray Thomson scattering from warm dense matter.

The influence of finite relaxation times on Thomson scattering from warm dense plasmas is examined within the framework of the average-atom approximation. Presently most calculations use the collision-free Lindhard dielectric function to evaluate the free-electron contribution to the Thomson cross section. In this work, we use the Mermin dielectric function, which includes relaxation time explicitly. The relaxation time is evaluated by treating the average atom as an impurity in a uniform electron gas and depends critically on the transport cross section. The calculated relaxation rates agree well with values inferred from the Ziman formula for the static conductivity and also with rates inferred from a fit to the frequency-dependent conductivity. Transport cross sections determined by the phase-shift analysis in the average-atom potential are compared with those evaluated in the commonly used Born approximation. The Born approximation converges to the exact cross sections at high energies; however, differences that occur at low energies lead to corresponding differences in relaxation rates. The relative importance of including relaxation time when modeling x-ray Thomson scattering spectra is examined by comparing calculations of the free-electron dynamic structure function for Thomson scattering using Lindhard and Mermin dielectric functions. Applications are given to warm dense Be plasmas, with temperatures ranging from 2 to 32 eV and densities ranging from 2 to 64 g/cc.

X-ray Thomson scattering measurements from hohlraum-driven spheres on the OMEGA laser.

X-ray Thomson scattering (XRTS) is a powerful diagnostic for probing warm and hot dense matter. We present the design and results of the first XRTS experiments with hohlraum-driven CH2 targets on the OMEGA laser facility at the Laboratory for Laser Energetics in Rochester, NY. X-rays seen directly from the XRTS x-ray source overshadow the elastic scattering signal from the target capsule but can be controlled in future experiments. From the inelastic scattering signal, an average plasma temperature is inferred that is in reasonable agreement with the temperatures predicted by simulations. Knowledge gained in this experiment shows a promising future for further XRTS measurements on indirectly driven OMEGA targets.

X-ray scattering measurements on imploding CH spheres at the National Ignition Facility.

We have performed spectrally resolved x-ray scattering measurements on highly compressed polystyrene at pressures of several tens of TPa (100 Mbar) created by spherically convergent shocks at the National Ignition Facility. Scattering data of line radiation at 9.0 keV were recorded from the dense plasma shortly after shock coalescence. Accounting for spatial gradients, opacity effects, and source broadening, we demonstrate the sensitivity of the elastic scattering component to carbon K-shell ionization while at the same time constraining the temperature of the dense plasma. For six times compressed polystyrene, we find an average temperature of 86 eV and carbon ionization state of 4.9, indicating that widely used ionization models need revision in order to be suitable for the extreme states of matter tested in our experiment.

Plasma conditions for improved energy coupling into the gain region of the Ni-like Pd transient collisional x-ray laser.

We have directly probed the conditions in which the Ni-like Pd transient collisional x-ray laser is generated and propagates by measuring the near-field image and by utilizing picosecond resolution soft x-ray laser interferometry of the preformed Pd plasma gain medium. The electron density and gain region of the plasma have been determined experimentally and are found to be in good agreement with simulations. We observe a strong dependence of the laser pump-gain medium coupling on the laser pump parameters. The most efficient coupling occurs with the formation of lower density gradients in the preformed plasma and when the duration of the main heating pulse is comparable to the gain lifetime (approximately 10 ps for mid- Z Ni-like schemes). This increases the output intensity by more than an order of magnitude relative to the commonly utilized case where the same pumping energy is delivered within a shorter heating pulse duration (<3 ps) . In contrast, the higher intensity heating pulses are observed to be absorbed at higher electron densities and in regions where steep density gradients limit the effective length of the gain medium.

Raloxifene induces neurite outgrowth in estrogen receptor positive PC12 cells.

OBJECTIVE: It is well established that gonadal steroids have direct in vivo and in vitro effects on neurons. To further study these effects, we used rat PC 12 cells to examine the effects of estrogen receptor (ER) ligands on neuronal morphology. DESIGN: PC 12 cells constitutively express ER beta, but only strongly express ER alpha after long-term priming with nerve growth factor (NGF). We therefore primed PC12 cells with NGF for 14 days before testing them for estradiol (10(-9)M)- and/or raloxifene (10(-7) M)-induced neurite growth. Neurite growth was assessed by quantitative light microscopy. As control, ER status of the PC12 cells was assessed by reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: In this study, both estradiol and raloxifene induced the outgrowth of neurites in NGF-treated PC 12 cells (p < 0.05). The combination of estradiol- and raloxifene-induced neurite growth was statistically greater than the effects of either agent alone. RT-PCR confirms that NGF-treated PC 12 cells express both ERalpha and ERbeta. CONCLUSIONS: This report is the first on the neurotrophic effect of raloxifene. At 10(-7) M, raloxifene's effect equaled that of estradiol; moreover, raloxifene did not block the neurite growth of simultaneously estradiol-treated PC 12 cells, despite its functional antiestrogenic effects in vivo. We conclude that raloxifene is estrogen agonistic in this animal model and therefore studies are warranted to delineate the relationship between steroidal estrogen and raloxifene.

Gain saturation regime for laser-driven tabletop, transient Ni-like ion X-Ray lasers

We have demonstrated small signal gain saturation on several transient-gain Ni-like ion x-ray lasers by using a high-power, chirped-pulse amplification, tabletop laser. These results have been achieved at wavelengths from 139-203 A using a total of 5-7 J energy in a traveling-wave excitation scheme. Strong amplification is also observed for Ni-like Sn at 119 A. Gain of 62 cm(-1) and gL product of 18 are determined on the 4d-->4p transition for Ni-like Pd at 147 A with an output energy of 12 &mgr;J. A systematic evaluation of the laser driver parameters yields optimum beam divergence and small deflection angles of 2-5 mrads, in good agreement with simulations.

Regulation of fas ligand expression in breast cancer cells by estrogen: functional differences between estradiol and tamoxifen.

During neoplastic growth and metastasis, the immune system responds to the tumor by developing both cellular and humoral immune responses. In spite of this active response, tumor cells escape immune surveillance. We previously showed that FasL expression by breast tumor plays a central role in the induction of apoptosis of infiltrating Fas-immune cells providing the mechanism for tumor immune privilege. In the present study, we showed that FasL in breast tissue is functionally active, and estrogen and tamoxifen regulate its expression. We identified an estrogen recognizing element like-motif in the promoter region of the FasL gene, suggesting direct estrogen effects on FasL expression. This was confirmed by an increase in FasL expression in both RNA and protein levels in hormone sensitive breast cancer cells treated with estradiol. This effect is receptor mediated since tamoxifen blocked the estrogenic effect. Interestingly, tamoxifen also inhibited FasL expression in estrogen-depleted conditions. Moreover, an increase in FasL in breast cancer cells induces apoptosis in Fas bearing T cells and, tamoxifen blocks the induction of apoptosis. These studies provide evidence that tamoxifen inhibits FasL expression, allowing the killing of cancer cells by activated lymphocytes. This partially explains the protective effect of tamoxifen against breast cancer.

Thomson scattering from a three-component plasma.

A model for a three-component plasma consisting of two distinct ionic species and electrons is developed and applied to study x-ray Thomson scattering. Ions of a specific type are assumed to be identical and are treated in the average-atom approximation. Given the plasma temperature and density, the model predicts mass densities, effective ionic charges, and cell volumes for each ionic type, together with the plasma chemical potential and free-electron density. Additionally, the average-atom treatment of individual ions provides a quantum-mechanical description of bound and continuum electrons. The model is used to obtain parameters needed to determine the dynamic structure factors for x-ray Thomson scattering from a three-component plasma. The contribution from inelastic scattering by free electrons is evaluated in the random-phase approximation. The contribution from inelastic scattering by bound electrons is evaluated using the bound-state and scattering wave functions obtained from the average-atom calculations. Finally, the partial static structure factors for elastic scattering by ions are evaluated using a two-component version of the Ornstein-Zernike equations with hypernetted chain closure, in which electron-ion interactions are accounted for using screened ion-ion interaction potentials. The model is used to predict the x-ray Thomson scattering spectrum from a CH plasma and the resulting spectrum is compared with experimental results obtained by Feltcher et al. [Phys. Plasmas 20, 056316 (2013)].

Thomson scattering in the average-atom approximation.

The average-atom model is applied to study Thomson scattering of x-rays from warm dense matter with emphasis on scattering by bound electrons. Parameters needed to evaluate the dynamic structure function (chemical potential, average ionic charge, free electron density, bound and continuum wave functions, and occupation numbers) are obtained from the average-atom model. The resulting analysis provides a relatively simple diagnostic for use in connection with x-ray scattering measurements. Applications are given to dense hydrogen, beryllium, aluminum, and titanium plasmas. In the case of titanium, bound states are predicted to modify the spectrum significantly.