Dynamics of Excited Electrons in Copper and Ferromagnetic Transition Metals: Theory and Experiment

Both theoretical and experimental results for the dynamics of photoexcited electrons at surfaces of Cu and the ferromagnetic transition metals Fe, Co, and Ni are presented. A model for the dynamics of excited electrons is developed, which is based on the Boltzmann equation and includes effects of photoexcitation, electron-electron scattering, secondary electrons (cascade and Auger electrons), and transport of excited carriers out of the detection region. From this we determine the time-resolved two-photon photoemission (TR-2PPE). Thus a direct comparison of calculated relaxation times with experimental results by means of TR-2PPE becomes possible. The comparison indicates that the magnitudes of the spin-averaged relaxation time \tau and of the ratio \tau_\uparrow/\tau_\downarrow of majority and minority relaxation times for the different ferromagnetic transition metals result not only from density-of-states effects, but also from different Coulomb matrix elements M. Taking M_Fe > M_Cu > M_Ni = M_Co we get reasonable agreement with experiments.Comment: 23 pages, 11 figures, added a figure and an appendix, updated reference

Zanos et al. reply

Clinical data have demonstrated rapid and sustained antidepressant effects of ketamine, a noncompetitive NMDAR (N-methyl-daspartate receptor) antagonist. Recently, Zanos et al.2 claimed that the ketamine metabolite (2R,6R)-hydroxynorketamine (HNK) is essential for the antidepressant effects of ketamine in mice in an NMDAR-independent manner, although no alternative mechanism was proposed, beyond unspecific activation of AMPAR (α -amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor). Here we report that (2R,6R)-HNK blocks synaptic NMDARs in a similar manner to its parent compound, and we show that the effects of (2R,6R)-HNK on intracellular signalling are coupled to NMDAR inhibition. These data demonstrate that (2R,6R)-HNK inhibits synaptic NMDARs and subsequently elicits the same signal transduction pathway previously associated with NMDAR inhibition by ketamine

Comparación de distintas estrategias para la predicción de muerte a corto plazo en el paciente anciano infectado

Objective. The aim of this study was to determine the utility of a post hoc lactate added to SIRS and qSOFA score to predict 30-day mortality in older non-severely dependent patients attended for infection in the Emergency Department (ED). Methods. We performed an analytical, observational, prospective cohort study including patients of 75 years of age or older, without severe functional dependence, attended for an infectious disease in 69 Spanish ED for 2-day three seasonal periods. Demographic, clinical and analytical data were collected. The primary outcome was 30-day mortality after the index event. Results. We included 739 patients with a mean age of 84.9 (SD 6.0) years; 375 (50.7%) were women. Ninety-one (12.3%) died within 30 days. The AUC was 0.637 (IC 95% 0.587-0.688; p= 2 and 0.698 (IC 95% 0.635- 0.761; p= 2. Comparing receiver operating characteristic (ROC) there was a better accuracy of qSOFA vs SIRS (p=0.041). Both scales improve the prognosis accuracy with lactate inclusion. The AUC was 0.705 (IC95% 0.652-0.758; p<0.001) for SIRS plus lactate and 0.755 (IC95% 0.696-0.814; p<0.001) for qSOFA plus lactate, showing a trend to statistical significance for the second strategy (p=0.0727). Charlson index not added prognosis accuracy to SIRS (p=0.2269) or qSOFA (p=0.2573). Conclusions. Lactate added to SIRS and qSOFA score improve the accuracy of SIRS and qSOFA to predict short-term mortality in older non-severely dependent patients attended for infection. There is not effect in adding Charlson index

Sensitivity Techniques For The Fast Assessment Of Security Margins To Voltage Collapse

This paper presents a simple, fast and efficient method for determining the security margin to voltage collapse (SMVC) of electric power systems. The computation procedure is based on the utilization of sensitivity techniques. The basic idea is that load increments influence the behavior of the reactive power injected by generators (slack and PV buses). Therefore, sensitivity analysis may be a very interesting tool for voltage stability analysis and applications. The proposed method, with a static approach, is based on solving a certain number of load flow calculations for different load levels. The path to reaching the maximum loading point, which allows the estimation of the SMVC consists of simple load increments or curtailments. The results are accurately obtained after a few load change steps.Kundur, P., (1994) Power system stability and control, , McGraw-HillDefinition and Classification of Power System Stability (2004) IEEE Transactions on Power Systems, 19 (2). , IEEE/CIGRE Joint Task Force on Stability Terms and DefinitionsPrada, R.B., Viera Filho, X., Voltage stability system critical area identification based on the existence of maximum power flow transmission (1993) Power Systems Computation Conference, 1Taylor, C.W., (1993) Power system voltage stability, , McGraw-HillVoltage stability of power systems: concepts, analytical tools, and industrial experience, IEEE 90TH0358-2-PWR, 1990Harmand, Y., Trotignon, M., Lesigne, J.F., Tesseron, J.M., Lemaitre, C., Bourgin, F., Analysis of a voltage collapse incident and proposal for a time-based hierarquical containment scheme CIGRÉ Report, , 38/39-02, 1990Calvaer, A.J., Van Geert, E., Quasi steady state synchronous machine linearization around an operating point and applications (1984) IEEE Transactions on Power Apparatus and Systems, PAS-103 (6)Walve, K., Modelling of power system components at severe disturbances CIGRÉ Report, , 38-18, 1986Prada, R.B., Souza, L.J., Voltage stability and thermal limit constraints on the maximum loading of electrical energy distribution feeders (1998) IEE Proceedings - Generation, Transmission and Distribution, 145 (5)States and Canada: Causes and recommendations (2004) Final report on the August, , http://www.nerc.com/filez/blackout.html, U.S.-Canada Power system outage task force, 14, 2003 Blackout in the United, April 5(2003) The anatomy of thursday's blackout, , http://www.electrotek.com/pressrel/blackout.htm, Electrotek concepts, IncWollenberg, B.F., From blackout to blackout (2004) IEEE Power & Energy MagazineA. Bose., Of squirrels and reliability, IEEE Power & Energy Magazine, 2004Van Cutsem, T., Moisse, C., Mailhot, R., Determination of secure operating limits with respect to voltage collapse (1999) IEEE Transactions on Power Systems, 14 (1)Young-Huei, H., Ching-Tsai, P., Wen-Wei, L., Fast Calculation of a Voltage Stability Index of Power Systems (1997) IEEE Transactions on Power Systems, 12 (4)Löf, P.-A., Andersson, G., Hill, D.J., Voltage Stability Indices for Stressed Power Systems (1993) IEEE Transactions on Power Systems, 8 (1)Cañizares, C., Souza, A.C.Z., Quintana, V., Comparison of Performance Indices for Detection of Proximity to Voltage Collapse (1996) IEEE Transactions on Power Systems, 11 (3)Mansour, Y. (Ed.), Suggested techniques for voltage stability analysis, 93TH0620-5PWR, IEEE, 1993Ajjarapu, V., Christy, C., The continuation power flow: A tool for steady state voltage stability analysis (1992) IEEE Transactions on Power Systems, 7 (1)Flatabø, N., Ognedal, R., Carlsen, T., Voltage stability condition in a power transmission system calculated by sensitivity methods (1990) IEEE Transactions on Power Systems, 5 (4)Flatabø, N., Fosso, O., Ognedal, R., Carlsen, T., A method for Calculation of Margins to Voltage Instability Applied on the Norwegian System for Maintaining Required Security Level (1993) IEEE Transactions on Power Systems, 8 (3)Ajjarapu, V., Lin, P., Battula, S., An Optimal Reactive Power Planning Strategy Against Voltage Collapse (1994) IEEE Transactions on Power Systems, 9 (2)Irissari, G.D., Wang, X., Mokhtari, S., Maximum loadability of power system using interior point nonlinear optimization method (1997) IEEE Transactions on Power Systems, 12 (1)Souza, A.C.Z., Honorio, L.M., Torres, G.L., Lambert-Torres, G., Increasing the Loadability of Power System Through Optimal-Local Control Actions (2004) IEEE Transactions on Power Systems, 19 (1)Souza, A.C.Z., Cañizares, C.A., Quintana, V.H., Critical bus and point of collapse determination using tangent vectors (1996) Proc. of the North American Power SymposiumZarate, L.A., Castro, C.A., Fast method for computing power systems security margins to voltage collapse (2004) IEE Proceedings - Generation, Transmission and Distribution, 151 (1)Overbye, T.J., A Power Flow Measure for Unsolvable Cases, IEEE Transactions on Power Systems, 9, n.3, 1994Braz, L.M., Castro, C.A., Murari, C.A.F., A Critical Evaluation of Step Size Optimization Based Load Flow Methods (2000) IEEE Transactions on Power Systems, 15 (1)Luenberger, D.G., (1984) Linear and Nonlinear Programming, , Addison-Wesleyhttp://www.ee.washington.edu/research/pstc

Ketamine for depression:Where do we go from here?

Since publication of the first randomized controlled trial describing rapid antidepressant effects of ketamine, several reports have confirmed the potential utility of this dissociative anesthetic medication for treatment of major depressive episodes, including those associated with bipolar disorder and resistant to other medications and electroconvulsive therapy. These reports have generated several questions with respect to who might respond to ketamine, how, and for how long. To start answering these questions. We used PubMed.gov and ClinicalTrials.gov to perform a systematic review of all available published data on the antidepressant effects of ketamine and of all recently completed, ongoing, and planned studies. To date, 163 patients, primarily with treatment-resistant depression, have participated in case studies, open-label investigations, or controlled trials. All controlled trials have used a within-subject, crossover design with an inactive placebo as the control. Ketamine administration has usually involved an anaesthesiologist infusing a single, subanesthetic, intravenous dose, and required hospitalization for at least 24 hours postinfusion. Response rates in the open-label investigations and controlled trials have ranged from 25% to 85% at 24 hours postinfusion and from 14% to 70% at 72 hours postinfusion. Although adverse effects have generally been mild, some patients have experienced brief changes in blood pressure, heart rate, or respiratory rate. Risk-benefit analyses support further research of ketamine for individuals with severe mood disorders. However, given the paucity of randomized controlled trials, lack of an active placebo, limited data on long-term outcomes, and potential risks, ketamine administration is not recommended outside of the hospital setting

Ketamine regulates the presynaptic release machinery in the hippocampus

In the search for new drug targets, that may help point the way to develop fast-acting treatments for mood disorders, we have explored molecular pathways regulated by ketamine, an NMDA receptor antagonist, which has consistently shown antidepressant response within a few hours of administration. Using Sprague-Dawley rats we investigated the effects of ketamine on the presynaptic release machinery responsible for neurotransmitter release at 1, 2 and 4h as well as 7 days after administration of a single subanesthetic dose of ketamine (15mg/kg). A large reduction in the accumulation of SNARE complexes was observed in hippocampal synaptic membranes after 1, 2 and 4h of ketamine administration. In parallel, we found a selective reduction in the expression of the synaptic vesicle protein synaptotagmin I and an increase in the levels of synapsin I in hippocampal synaptosomes suggesting a mechanism by which ketamine reduces SNARE complex formation, in part, by regulating the number of synaptic vesicles in the nerve terminals. Moreover, ketamine reduced Thr286-phosphorylated \u3b1CaMKII and its interaction with syntaxin 1A, which identifies CaMKII as a potential target for second messenger-mediated actions of ketamine. In addition, despite previous reports of ketamine-induced inhibition of GSK-3, we were unable to detect regulation of its activity after ketamine administration. Our findings demonstrate that ketamine rapidly induces changes in the hippocampal presynaptic machinery similar to those that are obtained only with chronic treatments with traditional antidepressants. This suggests that reduction of neurotransmitter release in the hippocampus has possible relevance for the rapid antidepressant effect of ketamine

Familial Aggregation and Coaggregation of Suicide Attempts and Comorbid Mental Disorders in Adults.

Clarification of the joint influence of familial patterns of suicide attempts and comorbid mental disorders can enhance the understanding and prevention of suicide attempts. To investigate the familial patterns of suicide attempts and comorbid mental disorders and their associations in a 2-site family study of mood and anxiety disorders. Data were obtained from 2 parallel community-based family studies conducted in the United States (National Institute of Mental Health [NIMH] study) and in Lausanne, Switzerland (PsyCoLaus study), on the comorbidity of mood and anxiety disorders. The study sample comprised 1119 adult probands and 5355 first-degree relatives. Data were collected and analyzed from October 2004 to December 2016. Lifetime suicide attempt and mental disorders in first-degree relatives, obtained through direct interviews or family history reports. The study included 1119 adult probands (675 female [60.3%] and a mean [SD] age of 50 [12.0] years) and 5355 first-degree relatives (2752 female [51.4%] and a mean [SD] age of 52 [1.5] years). Of these participants, 90 (8.0%) of 1119 probands and 199 (3.7%) of 5355 relatives had a lifetime history of suicide attempt. Those with such a history had higher rates of all mental disorders, a greater number of disorders, and statistically significantly poorer current and lifetime global functioning. After adjustment for age and sex, a statistically significant association between suicide attempts in probands and in relatives was found at the NIMH site (OR, 2.6; 95% CI, 1.5-4.7), at the Lausanne site (OR, 3.1; 95% CI, 1.6-6.0), and in the combined data (OR, 2.9; 95% CI, 1.9-4.5). All mood disorder subtypes and substance use disorders were statistically significantly associated with suicide attempts. The familial association between lifetime suicide attempts in probands and relatives was not statistically significant for the combined sample (OR, 1.6; 95% CI, 1.0-2.7) after adjustment for comorbid conditions in probands and relatives. Social anxiety disorder in probands was associated with suicide attempts in relatives (OR, 2.4; 95% CI, 1.7-3.5) after controlling for comorbid mood, anxiety, and substance use disorders. Familiality of suicide attempts appears to be explained by a history of mental disorders among those with suicide attempts; the novel finding of a common familial diathesis for suicide attempts and social anxiety, particularly in combination with mood disorders, has heuristic value for future research and may be a risk marker that can inform prevention efforts