Removal of luminal content protects the small intestine during hemorrhagic shock but is not sufficient to prevent lung injury.

The small intestine plays a key role in the pathogenesis of multiple organ failure following circulatory shock. Current results show that reduced perfusion of the small intestine compromises the mucosal epithelial barrier, and the intestinal contents (including pancreatic digestive enzymes and partially digested food) can enter the intestinal wall and transport through the circulation or mesenteric lymph to other organs such as the lung. The extent to which the luminal contents of the small intestine mediate tissue damage in the intestine and lung is poorly understood in shock. Therefore, rats were assigned to three groups: No-hemorrhagic shock (HS) control and HS with or without a flushed intestine. HS was induced by reducing the mean arterial pressure (30 mmHg; 90 min) followed by return of shed blood and observation (3 h). The small intestine and lung were analyzed for hemorrhage, neutrophil accumulation, and cellular membrane protein degradation. After HS, animals with luminal contents had increased neutrophil accumulation, bleeding, and destruction of E-cadherin in the intestine. Serine protease activity was elevated in mesenteric lymph fluid collected from a separate group of animals subjected to intestinal ischemia/reperfusion. Serine protease activity was elevated in the plasma after HS but was detected in lungs only in animals with nonflushed lumens. Despite removal of the luminal contents, lung injury occurred in both groups as determined by elevated neutrophil accumulation, permeability, and lung protein destruction. In conclusion, luminal contents significantly increase intestinal damage during experimental HS, suggesting transport of luminal contents across the intestinal wall should be minimized

A high-energy inelastic neutron scattering investigation of the Gd-Co exchange interactions in GdCo4B: Comparison with density-functional calculations

International audienceInelastic neutron scattering is used to quantify the Gd-Co exchange interaction in GdCo4B. A significant reduction is observed in comparison with the GdCo5 compound. A mean value of 130 T is obtained for the exchange field on the two Gd sites in GdCo4B. The experimental results are compared with density-functional calculations. The local atomic magnetic moments calculated using the LSDA+U approximation are reported for each atomic site of the GdCo4B crystal structure. These calculations demonstrate that the two nonequivalent Gd crystal sites experience a significantly different exchange interaction, a difference that is discussed in the light of the local atomic environment. The observed reduction of the exchange field occurring upon substituting B for Co in GdCo5 is mainly caused by the decrease of the Co magnetic moment, whereas the Gd-Co coupling constant is found to be almost the same in both GdCo5 and GdCo4B

Co dimers on hexagonal carbon rings proposed as subnanometer magnetic storage bits

It is demonstrated by means of density functional and ab-initio quantum chemical calculations, that transition metal - carbon systems have the potential to enhance the presently achievable area density of magnetic recording by three orders of magnitude. As a model system, Co_2-benzene with a diameter of 0.5 nm is investigated. It shows a magnetic anisotropy in the order of 0.1 eV per molecule, large enough to store permanently one bit of information at temperatures considerably larger than 4 K. A similar performance can be expected, if cobalt dimers are deposited on graphene or on graphite. It is suggested that the subnanometer bits can be written by simultaneous application of a moderate magnetic and a strong electric field.Comment: 13 pages, 4 figure

Individual differences in short-term social dynamics: Theoretical perspective and empirical development of the social dynamics scale

People have a need to form and maintain fulfilling social contact, yet they differ with respect to with whom they satisfy the need and how quickly this need is deprived or overly satiated. These social dynamics across relationships and across time are theoretically delineated in the current article. Furthermore, we developed a questionnaire to measure individual differences in three aspects of such social dynamics: (a) Family-friends interdependence, (b) Social deprivation, and (c) Social oversatiation. In a longitudinal study spanning 9 weeks in spring 2020, in total 471 participants (18–75 years, 47% women) answered the newly developed items on social dynamics, questionnaires on social dispositions (e.g., affiliation motive, need to be alone, social anxiety), and questions on personal and indirect contact with family and friends during nationwide contact restrictions related to COVID-19. The results showed that individual differences in Family-friends interdependence, Social deprivation, and Social oversatiation can be measured reliably, validly, and with predictive value for changes in daily contact as contact restrictions were loosened. We discuss potential applications of the Social Dynamics Scale (SDS) for studying social relationships in healthy and clinical populations, and conclude that the brief self-report questionnaire of social dynamics can be useful for situations and samples where direct behavioral observations are not feasible

Symmetry Classes in Graphene Quantum Dots: Universal Spectral Statistics, Weak Localization, and Conductance Fluctuations

We study the symmetry classes of graphene quantum dots, both open and closed, through the conductance and energy level statistics. For abrupt termination of the lattice, these properties are well described by the standard orthogonal and unitary ensembles. However, for smooth mass confinement, special time-reversal symmetries associated with the sublattice and valley degrees of freedom are critical: they lead to block diagonal Hamiltonians and scattering matrices with blocks belonging to the unitary symmetry class even at zero magnetic field. While the effect of this structure is clearly seen in the conductance of open dots, it is suppressed in the spectral statistics of closed dots, because the intervalley scattering time is shorter than the time required to resolve a level spacing in the closed systems but longer than the escape time of the open systems.Comment: 4 pages, 4 figures, RevTex, submitted to Phys. Rev. Let

Life events and life satisfaction: Estimating effects of multiple life events in combined models

How do life events affect life satisfaction? Previous studies focused on a single event or separate analyses of several events. However, life events are often grouped non-randomly over the lifespan, occur in close succession, and are causally linked, raising the question of how to best analyze them jointly. Here, we used representative German data (SOEP; N = 40,121 individuals; n = 41,402 event occurrences) to contrast three fixed-effects model specifications: First, individual event models in which other events were ignored, which are thus prone to undercontrol bias; second, combined event models which controlled for all events, including subsequent ones, which may induce overcontrol bias; and third, our favored combined models that only controlled for preceding events. In this preferred model, the events of new partner, cohabitation, marriage, and childbirth had positive effects on life satisfaction, while separation, unemployment, and death of partner or child had negative effects. Model specification made little difference for employment- and bereavement-related events. However, for events related to romantic relationships and childbearing, small but consistent differences arose between models. Thus, when estimating effects of new partners, separation, cohabitation, marriage, and childbirth, care should be taken to include appropriate controls (and omit inappropriate ones) to minimize bias