Circular dichroism in hard X-ray photoelectron diffraction observed by time-of-flight momentum microscopy.

X-ray photoelectron diffraction (XPD) is a powerful technique that yields detailed structural information of solids and thin films that complements electronic structure measurements. Among the strongholds of XPD we can identify dopant sites, track structural phase transitions, and perform holographic reconstruction. High-resolution imaging of kll-distributions (momentum microscopy) presents a new approach to core-level photoemission. It yields full-field kx-ky XPD patterns with unprecedented acquisition speed and richness in details. Here, we show that beyond the pure diffraction information, XPD patterns exhibit pronounced circular dichroism in the angular distribution (CDAD) with asymmetries up to 80%, alongside with rapid variations on a small kll-scale (0.1 Å-1). Measurements with circularly-polarized hard X-rays (hν = 6 keV) for a number of core levels, including Si, Ge, Mo and W, prove that core-level CDAD is a general phenomenon that is independent of atomic number. The fine structure in CDAD is more pronounced compared to the corresponding intensity patterns. Additionally, they obey the same symmetry rules as found for atomic and molecular species, and valence bands. The CD is antisymmetric with respect to the mirror planes of the crystal, whose signatures are sharp zero lines. Calculations using both the Bloch-wave approach and one-step photoemission reveal the origin of the fine structure that represents the signature of Kikuchi diffraction. To disentangle the roles of photoexcitation and diffraction, XPD has been implemented into the Munich SPRKKR package to unify the one-step model of photoemission and multiple scattering theory.

Behavior problems reduce academic outcomes among primary students: A moderated mediation of parental burnout and parents' self-compassion.

The present study examines the mediating role of parental burnout in the relationship between students' behavior problems and academic outcomes and whether this mediating process is moderated by parents' self-compassion (PSC). This study was designed according to a cross-sectional study model, and includes 821 Vietnamese primary students (Mage = 9.98, SD = 0.889) completing behavior problems questionnaires. The parents completed parental burnout and the PSC questionnaires. The school office reported academic outcomes. Main findings include: (1) Student's behavior problems have a direct negative influence on academic outcomes; (2) the mediating role of parental burnout was significant; (3) the moderating role of PSC was also significant. This study suggests that students' behavior problems increase parental burnout, reducing academic outcomes. Next, higher self-compassion protected parents from the negative effect of children's behavior problems. The results of this study are meaningful for developing interventions, which help improve parents' mental health and children's positive outcomes.

Multicriteria assessment of advanced treatment technologies for micropollutants removal at large-scale applications.

With the introduction and discharge of thousands of new micropollutants (MPs) every year, traditional water and wastewater treatment plants may be incapable of tackling them all. With their low concentrations and diversity in nature, MP removal encounters numerous challenges. Although some MPs are effectively eliminated via conventional treatment methods, most of them can easily escape and are retained in the discharged effluent. Therefore, advanced methods such as (i) adsorption, (ii) oxidation and advanced oxidation processes (O3 and O3-based advanced oxidation processes, UV/H2O2), (iii) membrane processes, and (iv) membrane bioreactors, become an inevitable approach. Despite the unsurprisingly vast number of papers on MP treatment available at present, most of these studies were carried out at a laboratory scale while only a few pilot- and full-scale studies have experimented. Nevertheless, an in-depth assessment of real-world MP treatment methods is extremely crucial for practitioners. To date, no paper has been dedicated to look at this issue. Therefore, this paper aims to review these large-scale treatment methods. First, the paper goes through the regulations and standards which deal with MPs in water courses. It will then assess these methods in various case-studies with reference to different criteria towards serving as a reference for further practical applications.

Near-field probing of slow Bloch modes on photonic crystals with a nanoantenna.

We study the near-field probing of the slow Bloch laser mode of a photonic crystal by a bowtie nano-aperture (BNA) positioned at the end of a metal-coated fiber probe. We show that the BNA acts as a polarizing nanoprobe allowing us to extract information about the polarization of the near-field of the slow-light mode, without causing any significant perturbation of the lasing process. Near-field experiments reveal a spatial resolution better than λ/20 and a polarization ratio as strong as 110. We also demonstrate that the collection efficiency is two orders of magnitude larger for the BNA than for a 200 nm large circular aperture opened at the apex of the same metal-coated fiber tip. The BNA allows for overcoming one of the main limitations of SNOM linked to the well-known trade off between resolution and signal-to-noise ratio.

NF-κB mediates the 12(S)-HETE-induced endothelial to mesenchymal transition of lymphendothelial cells during the intravasation of breast carcinoma cells.

BACKGROUND: The intravasation of breast cancer into the lymphendothelium is an early step of metastasis. Little is known about the mechanisms of bulky cancer invasion into lymph ducts. METHODS: To particularly address this issue, we developed a 3-dimensional co-culture model involving MCF-7 breast cancer cell spheroids and telomerase-immortalised human lymphendothelial cell (LEC) monolayers, which resembles intravasation in vivo and correlated the malignant phenotype with specific protein expression of LECs. RESULTS: We show that tumour spheroids generate 'circular chemorepellent-induced defects' (CCID) in LEC monolayers through retraction of LECs, which was induced by 12(S)-hydroxyeicosatetraenoic acid (HETE) secreted by MCF-7 spheroids. This 12(S)-HETE-regulated retraction of LECs during intravasation particularly allowed us to investigate the key regulators involved in the motility and plasticity of LECs. In all, 12(S)-HETE induced pro-metastatic protein expression patterns and showed NF-κB-dependent up-regulation of the mesenchymal marker protein S100A4 and of transcriptional repressor ZEB1 concomittant with down-regulation of the endothelial adherence junction component VE-cadherin. This was in accordance with ∼50% attenuation of CCID formation by treatment of cells with 10 µM Bay11-7082. Notably, 12(S)-HETE-induced VE-cadherin repression was regulated by either NF-κB or by ZEB1 since ZEB1 siRNA knockdown abrogated not only 12(S)-HETE-mediated VE-cadherin repression but inhibited VE-cadherin expression in general. INTERPRETATION: These data suggest an endothelial to mesenchymal transition-like process of LECs, which induces single cell motility during endothelial transmigration of breast carcinoma cells. In conclusion, this study demonstrates that the 12(S)-HETE-induced intravasation of MCF-7 spheroids through LECs require an NF-κB-dependent process of LECs triggering the disintegration of cell-cell contacts, migration, and the generation of CCID.

Cellular senescence involves stochastic processes causing loss of expression of differentiated function genes: transfection with SV40 as a means for dissociating effects of senescence on growth and on differentiated function gene expression.

In the accompanying work we demonstrated that the decline in expression of steroid 17 alpha-hydroxylase in mass cultures and clones of adrenocortical cells is the result of a stochastic switching process which yields mixtures of expressing and nonexpressing cells. There is an apparent positive correlation between the replicative potential of adrenocortical cell cultures and the number of cells in the culture that can express 17 alpha-hydroxylase. We investigated this by extending the cells' replicative potential by transfecting them with cloned SV40 virus. Cells from a senescent subclone, with very limited remaining replicative potential, were transfected. The cell population showed a progressive increase in growth rate and gave rise to a line of cells that expressed T antigen and which was apparently immortalized. Induction of mRNA for 17 alpha-hydroxylase by cyclic AMP was absent in this line of cells, as it was in the senescent cells prior to transfection. The cells remained responsive to gene induction by cyclic AMP as evidenced by increases in mRNA and activity for cholesterol side-chain cleavage. The absence of 17 alpha-hydroxylase expression in this line was not the result of interference by SV40 T antigen. When early passage cells were transfected with pSV3neo, which contains the early region of SV40 and neo, and were selected with G418, SV40 T antigen-expressing lines were derived which showed high levels of expression of 17 alpha-hydroxylase after induction with cyclic AMP. These cells maintained high levels of expression of 17 alpha-hydroxylase through four successive recloning events, over a period of replication much longer than that achievable by nontransfected cells. Thus, transfection by SV40 can be used to dissociate effects of senescence on growth and differentiated gene expression. T antigen expression selectively affects growth, but preserves the state of expression of a differentiated function gene as it was prior to transfection.

Loss of expression of a differentiated function gene, steroid 17 alpha-hydroxylase, as adrenocortical cells senescence in culture.

Senescence in cultured adrenocortical cells involves changes in expression of differentiated functions as well as changes in responses to mitogenic stimulation. Steroid 17 alpha-hydroxylase (steroid 17 alpha-monooxygenase, EC 1.14.99.9) is an adrenal-specific enzyme, the expression of which is dependent on the presence of stimulators of cyclic AMP production, such as cholera toxin. Dot-blot hybridization of RNA from bovine adrenocortical cells that had been incubated with cholera toxin showed a marked decline in 17 alpha-hydroxylase mRNA levels as a function of population doubling level, closely paralleling the decline in induction of 17 alpha-hydroxylase enzyme activity. The lower levels of 17 alpha-hydroxylase induction did not result from a requirement for a longer time period for induction or from a specific defect in response to cholera toxin and were not caused by a general failure of enzyme induction in response to cyclic AMP. The decreased growth rate in older cells results from a general decline in response to several growth factors. However, the decline in 17 alpha-hydroxylase induction did not result from a loss of response of the cells to mitogens, since quiescent cells at a low population doubling level showed stimulation of 17 alpha-hydroxylase mRNA by cholera toxin to levels similar to those in nonquiescent cultures and added mitogens either had no effect on 17 alpha-hydroxylase mRNA levels or decreased them. There was, however, a specific posttranscriptional effect of insulin on 17 alpha-hydroxylase. The loss of 17 alpha-hydroxylase induction is unlikely to result from overgrowth of a minority cell type lacking the ability to induce 17 alpha-hydroxylase, because adrenocortical cell clones that had high levels of 17 alpha-hydroxylase induction gave rise to cells with lower levels of induction on subcloning. Thus, loss of 17 alpha-hydroxylase activity in adrenocortical cellular senescence results from a primary failure of accumulation of 17 alpha-hydroxylase mRNA after incubation with the inducing agent.