Compartmentalized Connexin 43 S-Nitrosylation/Denitrosylation Regulates Heterocellular Communication in the Vessel Wall

Objective-To determine whether S-nitrosylation of connexins (Cxs) modulates gap junction communication between endothelium and smooth muscle. Methods and Results-Heterocellular communication is essential for endothelium control of smooth muscle constriction; however, the exact mechanism governing this action remains unknown. Cxs and NO have been implicated in regulating heterocellular communication in the vessel wall. The myoendothelial junction serves as a conduit to facilitate gap junction communication between endothelial cells and vascular smooth muscle cells within the resistance vasculature. By using isolated vessels and a vascular cell coculture, we found that Cx43 is constitutively S-nitrosylated on cysteine 271 because of active endothelial NO synthase compartmentalized at the myoendothelial junction. Conversely, we found that stimulation of smooth muscle cells with the constrictor phenylephrine caused Cx43 to become denitrosylated because of compartmentalized S-nitrosoglutathione reductase, which attenuated channel permeability. We measured S-nitrosoglutathione breakdown and NOx concentrations at the myoendothelial junction and found S-nitrosoglutathione reductase activity to precede NO release. Conclusion-This study provides evidence for compartmentalized S-nitrosylation/denitrosylation in the regulation of smooth muscle cell to endothelial cell communication. (Arterioscler Thromb Vasc Biol. 2011;31:399-407.

Acetabular fracture: Long-term follow-up and factors associated with secondary implantation of total hip arthroplasty

SummaryHypothesisThe present study sought to determine long-term outcome in acetabular fracture and the factors associated with secondary implantation of a total hip arthroplasty and/or with poor functional results.Material and methodsSeventy-two patients admitted between 2000 and 2005 were followed up for a maximum 11years (mean, 6.8years): 16 females, 56 males; mean age at injury, 41.6years (median, 40years). There were 45 simple acetabular fractures, 27 complex fractures and 27 dislocations. Late complications were: osteoarthritis (n=29), osteonecrosis of the femoral head (ONFH: n=8) and heterotopic ossification (n=2).Results and discussionTwenty-five total hip arthroplasties (THA) were performed, with a mean time to surgery of 3.7years. Associated factors for THA were: VAS (P<0.0001), PMA (P<0.0001), osteoarthritis (P<0.0001), ONFH (P<0.0002), initial dislocation (P=0.0002), no functional treatment (P=0.0014), surgical treatment (P=0.0065), initial traction (P=0.0068), anterior and posterior congruency defect (P=0.0072 and P<0.0001), and initial intra-articular foreign body (P=0.045). Factors associated with poor or bad functional results were the same, plus: etiology (P=0.0021), BMI (P=0.03) and posterior wall fracture (P=0.0325).Level of evidence4; retrospective study

Observer pour comprendre les interactions de la biodiversité avec les pratiques agricoles : premiers résultats de l’Observatoire Agricole de la Biodiversité

Ce numéro est constitué d’articles issus du colloque « Biodiversité et durabilité des agricultures » qui s’est tenu à Paris le 11 avril 2019Alors que l’agriculture et la biodiversité sont en interrelation forte, il n’existait pas jusque récemment desuivi de biodiversité ciblant les espaces agricoles. L’Observatoire Agricole de la Biodiversité (OAB) a étélancé en 2011 à l’initiative du ministère de l’agriculture. L’OAB est le premier projet national impliquantdes agriculteurs dans l'observation de la biodiversité, grâce à des protocoles simples mais standardisésde suivi de quatre groupes importants pour l’agriculture. L’OAB a un double objectif : (1) scientifique,pour mieux comprendre les relations entre pratiques et biodiversité, et documenter des tendancestemporelles de la biodiversité et (2) de sensibilisation, comme outil de recherche de réponsestechniques pour les agriculteurs. Entre 2011 et 2018, les agriculteurs participants ont effectué desobservations dans 2770 parcelles. Les premiers résultats permettent de retrouver des effets bienconnus des pratiques sur la biodiversité, mais surtout de détecter des premières tendances temporellesaprès seulement huit années de suivi. Par exemple les abeilles solitaires déclinent en général, saufdans les parcelles avec des pratiques peu intensives. L’OAB doit désormais monter en puissance, avecdavantage d’observateurs et de protocoles, afin de confirmer ces tendances et d’identifier des pratiquesvertueuses pour la conservation de la biodiversité dans les espaces agricoles

Circular dichrosim in photoionization of H2 and D2

ABSTRACT: In this work, circular dichroism in H2 (D2) photoionization is studied in detail. We have selected several photon energies for a case study: 19 eV for which only direct ionization to the 1s_g ionization channel is present, 27 eV where autoionization of Q1 doubly excited states takes place, and 32.5 eV for which autoionization from Q1 and doubly excited states and direct ionization to 1s_g and 2p_u channels strongly interfere. The latter case shows clear evidence of different behavior of the photoionization against radiation helicity

Circular dichroism in photoionization of H2

ABSTRACT: Circular dichroism is a consequence of chirality. However, nonchiral molecules can also exhibit it when the measurement itself introduces chirality, e.g., when measuring molecular-frame photoelectron angular distributions. The few such experiments performed on homonuclear diatomic molecules show that, as expected, circular dichroism vanishes when the molecular-frame photoelectron angular distributions are integrated over the polar electron emission angle. Here we show that this is not the case in resonant dissociative ionization of H2 for photons of 30–35 eV, which is the consequence of the delayed ionization from molecular doubly excited states into ionic states of different inversion symmetry

Between learning and schooling: the politics of human rights monitoring at the Universal Periodic Review

This paper explores the politics of monitoring at the Universal Periodic Review (UPR), a new United Nations human rights monitoring mechanism which aims to promote a universal approach and equal treatment when reviewing each country’s human rights situation. To what extent are these laudable aims realised, and realisable, given entrenched representations of the West and the Rest as well as geopolitical and economic inequalities both historically and in the present? Based on ethnographic fieldwork at the UN in 2010–11, the final year of the UPR’s first cycle, we explore how these aims were both pursued and subverted, paying attention to two distinct ways of talking about the UPR: first, as a learning culture in which UN member states ‘share best practice’ and engage in constructive criticism; and second, as an exam which UN member states face as students with vastly differing attitudes and competences. Accounts and experiences of diplomats from states that are not placed in the ‘good students’ category offer valuable insights into the inherent contradictions of de-historicised and de-contextualised approaches to human rights

Stark Effect of Interactive Electron-hole pairs in Spherical Semiconductor Quantum Dots

We present a theoretical variational approach, based on the effective mass approximation (EMA), to study the quantum-confinement Stark effects for spherical semiconducting quantum dots in the strong confinement regime of interactive electron-hole pair and limiting weak electric field. The respective roles of the Coulomb potential and the polarization energy are investigated in details. Under reasonable physical assumptions, analytical calculations can be performed. They clearly indicate that the Stark shift is a quadratic function of the electric field amplitude in the regime of study. The resulting numerical values are found to be in good agreement with experimental data over a significant domain of validity

Rate Dependent Performance Related to Crystal Structure Evolution of Na0.67Mn0.8Mg0.2O2 in a Sodium-Ion Battery

Sodium-ion batteries are considered as a favorable alternative to the widely used lithium-ion batteries for applications such as grid-scale energy storage. However, to meet the energy density and reliability that is necessary, electrodes that are structurally stable and well characterized during electrochemical cycling need to be developed. Here, we report on how the applied discharge current rate influences the structural evolution of Na0.67Mn0.8Mg0.2O2 electrode materials. A combination of ex situ and in situ X-ray diffraction (XRD) data were used to probe the structural transitions at the discharged state and during charge/discharge. Ex situ data shows a two-phase electrode at the discharged state comprised of phases that adopt Cmcm and P63/mmc symmetries at the 100 mA/g rate but a predominantly P63/mmc electrode at 200 and 400 mA/g rates. In situ synchrotron XRD data at 100 mA/g shows a solely P63/mmc electrode when 12 mA/g charge and 100 mA/g discharge is used even though ex situ XRD data shows the p..

Classification and Functional Characterization of Vasa Vasorum-Associated Perivascular Progenitor Cells in Human Aorta

In the microcirculation, pericytes are believed to function as mesenchymal stromal cells (MSCs). We hypothesized that the vasa vasorum harbor progenitor cells within the adventitia of human aorta. Pericytes, endothelial progenitor cells, and other cell subpopulations were detected among freshly isolated adventitial cells using flow cytometry. Purified cultured pericytes were enriched for the MSC markers CD105 and CD73 and depleted of the endothelial markers von Willebrand factor and CD31. Cultured pericytes were capable of smooth muscle lineage progression including inducible expression of smooth muscle myosin heavy chain, calponin, and α-smooth muscle actin, and adopted a spindle shape. Pericytes formed spheroids when cultured on Matrigel substrates and peripherally localized with branching endothelial cells in vitro. Our results indicate that the vasa vasorum form a progenitor cell niche distinct from other previously described progenitor populations in human adventitia. These findings could have important implications for understanding the complex pathophysiology of human aortic disease