Validation of a Sapphire Gas-Pressure Cell for Real-Time In Situ Neutron Diffraction Studies of Hydrogenation Reactions

A gas-pressure cell, based on a leuco-sapphire single-crystal, serving as a pressure vessel and sample holder, is presented for real time in situ studies of solid-gas hydrogenation reactions. A stainless steel corpus, coated with neutron absorbing varnish, allows alignment for the single-crystal sample holder for minimizing contributions to the diffraction pattern. Openings in the corpus enable neutron scattering as well as contactless temperature surveillance and laser heating. The gas-pressure cell is validated via the deuteration of palladium powder, giving reliable neutron diffraction data at the high-intensity diffractometer D20 at the Institut Laue-Langevin (ILL), Grenoble, France. It was tested up to 15.0 MPa of hydrogen pressure at room temperature, 718 K at ambient pressure and 584 K at 9.5 MPa of hydrogen pressure

Size Matters: New Zintl Phase Hydrides of REGa (RE = Y, La, Tm) and RESi (RE = Y, Er, Tm) with Large and Small Cations

Many Zintl phases exhibiting a CrB type structure form hydrides. Systematic studies of AeTtHx (Ae = Ca, Sr, Ba; Tt = Si, Ge, Sn), LnTtHx (Ln = La, Nd; Tt = Si, Ge, Sn), and LnGaHx (Ln = Nd, Gd) showed the vast structural diversity of these systems. Hydrogenation reactions on REGa (RE = Y, La, Tm) and RESi (RE = Y, Er, Tm) were performed in steel autoclaves under hydrogen pressure up to 5 MPa and temperatures up to 773 K. The products were analyzed by X-ray and neutron powder diffraction. RESi (RE = Y, Er, Tm) form hydrides in the C-LaGeD type. LaGaD1.66 is isostructural to NdGaD1.66 and shows similar electronic features. Ga-D distances (1.987(13) Å and 2.396(9) Å) are considerably longer than in polyanionic hydrides and not indicative of covalent bonding. In TmGaD0.93(2) with a distorted CrB type structure deuterium atoms exclusively occupy tetrahedral voids. Theoretical calculations on density functional theory (DFT) level confirm experimental results and suggest metallic properties for the hydrides

Endothelial function in normotensive and high-normal hypertensive subjects

To evaluate the impact of a mild increment in blood pressure level on endothelial function, we evaluated 61 healthy volunteers (24 women, 37 men, and aged 35-50 years). All subjects underwent a blood chemistry panel to exclude any metabolic abnormalities and were submitted to a Doppler ultrasound of the brachial artery to assess endothelial function. We assessed the endothelial response to reactive hyperaemia and exogenous nitric oxide administration considering an increase in systolic blood pressure (SBP) at each 10-mm Hg interval. Our study population was divided as follows: SBP = 115 mm Hg and = 125 mm Hg and = 135 mm Hg and <140 mm Hg (SG4, n = 15). We found a significant difference in flow-mediated dilation among SG2, SG3 and SG4, 16.2 +/- 5.6, 13.4 +/- 5.2 and 11.5 +/- 3.6%, P < 0.05, respectively). After nitrate administration, we observed a nonsignificant decrease in brachial artery dilation among groups, P = 0.217. Our data showed in a healthy normotensive population, without any risk factor for atherosclerotic disease that small increases in SBP but not in diastolic blood pressure may impair endothelial function even in subjects considered as high-normal, meaning that this population deserves more attention than usually ascribed to intervene and prevent complications, as endothelial dysfunction may represent an early change in those who develop hypertension later in life.Universidade Federal de São Paulo, Div Nephrol, Escola Paulista Med, BR-04025011 São Paulo, SP, BrazilUniversidade Federal de São Paulo, Hosp Rim & Hipertensao, Escola Paulista Med, BR-04025011 São Paulo, SP, BrazilUniversidade Federal de São Paulo, Dept Radiol, Escola Paulista Med, BR-04025011 São Paulo, SP, BrazilUniversidade Federal de São Paulo, Div Nephrol, Escola Paulista Med, BR-04025011 São Paulo, SP, BrazilUniversidade Federal de São Paulo, Hosp Rim & Hipertensao, Escola Paulista Med, BR-04025011 São Paulo, SP, BrazilUniversidade Federal de São Paulo, Dept Radiol, Escola Paulista Med, BR-04025011 São Paulo, SP, BrazilWeb of Scienc

Reduced Serum Levels of Bone Formation Marker P1NP in Psoriasis

Psoriasis is a chronic inflammatory disease of the skin and joints. More recent data emphasize an association with dysregulated glucose and fatty acid metabolism, obesity, elevated blood pressure and cardiac disease, summarized as metabolic syndrome. TNF-a and IL-17, central players in the pathogenesis of psoriasis, are known to impair bone formation. Therefore, the relation between psoriasis and bone metabolism parameters was investigated. Two serum markers of either bone formation—N-terminal propeptide of type I procollagen (P1NP) or bone resorption—C-terminal telopeptide of type I collagen (CTX-I)—were analyzed in a cohort of patients with psoriasis vulgaris. In patients with psoriasis, P1NP serum levels were reduced compared to gender-, age-, and body mass index-matched healthy controls. CTX-I levels were indistinguishable between patients with psoriasis and controls. Consistently, induction of psoriasis-like skin inflammation in mice decreases bone volume and activity of osteoblasts. Moreover, efficient anti-psoriatic treatment improved psoriasis severity, but did not reverse decreased P1NP level suggesting that independent of efficient skin treatment psoriasis did affect bone metabolism and might favor the development of osteoporosis. Taken together, evidence is provided that bone metabolism might be affected by psoriatic inflammation, which may have consequences for future patient counseling and disease monitoring

Second Harmonic Generation from Grating-Coupled Hybrid Plasmon-Phonon Polaritons

Polaritons can provide strong optical field enhancement allowing to boost light-matter interaction. Here, we experimentally observe enhancement of mid-infrared second-harmonic generation (SHG) using grating-coupled surface phonon polaritons of the 6H-SiC surface. In our experiment, we measure the SHG along the polariton dispersion by changing the incidence angle of the excitation beam. We observe hybridization between the propagating surface phonon polaritons and localized plasmon resonances in the gold grating, evidenced by the modification of the polariton dispersion as we change the area ratio of grating and substrate. Design options for engineering the plasmon-phonon polariton hybridization are discussed. Overall, we find a rather low yield of polariton-enhanced SHG in this geometry compared to prism-coupling and nanostructures, and discuss possible origins

Health Care for Persistent Somatic Symptoms Across Europe: A Qualitative Evaluation of the EURONET-SOMA Expert Discussion

Background: Persistent somatic symptoms (PSS), referred to as somatoform disorders and lately somatic symptom disorders, are frequent but often remain under-recognized and under-treated. Although European guidelines overlap, presumably, there is large diversity in their practical use and in the actual health care situation. The aim of this qualitative evaluation was to compare health care for PSS across 9 European countries, to illustrate commonalities and differences, and to discuss challenges for a pan-European research agenda.Methods: A case vignette fulfilling ICD-10 criteria of undifferentiated somatization disorder was presented to 24 experts from 9 European countries, who completed a semi-structured assessment regarding the routine management including diagnostic procedures, treatment recommendations, and country-specific health care aspects. A qualitative evaluation was conducted using the video-transcripts of the presentations. Results were validated by additional expert interviews.Results: Across all countries, primary care physicians serve as the gate keeper for further diagnostic and treatment procedures. Apart from this commonality, there is a large variability in health care routines. Experts concluded that individuals with PSS appear to be a non-identified patient group within many European health care systems. To overcome the gap between evidence-based guidelines and clinical reality needs, three key challenges were identified: (1) Defining a clinically useful, acceptable, and non-stigmatizing diagnostic term, (2) implementing guideline recommendations into routine care, (3) developing effective dissemination strategies.Conclusions: The results advocate for more research on the actual European health care situation. A systematic European research agenda with unified goals and interdisciplinary collaboration that integrates all stakeholders could answer this challenge

The curvature of semidirect product groups associated with two-component Hunter-Saxton systems

In this paper, we study two-component versions of the periodic Hunter-Saxton equation and its $\mu$-variant. Considering both equations as a geodesic flow on the semidirect product of the circle diffeomorphism group \Diff(\S) with a space of scalar functions on $\S$ we show that both equations are locally well-posed. The main result of the paper is that the sectional curvature associated with the 2HS is constant and positive and that 2$\mu$HS allows for a large subspace of positive sectional curvature. The issues of this paper are related to some of the results for 2CH and 2DP presented in [J. Escher, M. Kohlmann, and J. Lenells, J. Geom. Phys. 61 (2011), 436-452].Comment: 19 page