1,282 research outputs found
Temperature dependence of absorption in photorefractive iron-doped lithium niobate crystals
We present experimental data showing a significant dependence of light absorption on temperature in photorefractive LiNbO3:Fe crystals. The results are successfully explained by assuming that the widths of the Fe2+ absorption bands in the visible and in the infrared spectral region depend on temperature. The findings are of relevance for thermal fixing of holograms. Furthermore, a temperature-induced increase of the infrared absorption is promising for improved infrared recording
Poling effect on distribution of quenched random fields in a uniaxial relaxor ferroelectric
The frequency dependence of the dielectric permitivity's maximum has been
studied for poled and unpoled doped relaxor strontium barium niobate
(SBN-61:Cr). In both cases the maximum
found is broad and the frequency dispersion is strong. The present view of
random fields compensation in the unpoled sample is not suitable for explaining
this experimental result. We propose a new mechanism where the dispersion of
quenched random electric fields, affecting the nanodomains, is minimized after
poling. We test our proposal by numerical simulations on a random field Ising
model. Results obtained are in agreement with the polarization's measurements
presented by Granzow et al. [Phys. Rev. Lett {\bf 92}, 065701 (2004)].Comment: 7 pages, 4 figure
Langzeitmedikation und perioperatives Management
Zusammenfassung: Anästhesisten und Operateure sehen sich zunehmend mit Patienten konfrontiert, die unter einer medikamentösen Dauertherapie stehen. Ein Teil dieser Medikamente können mit Anästhetika oder anästhesiologischen und/oder chirurgischen Interventionen interagieren. Als Folge können Komplikationen wie Blutungen, Ischämien, Infektionen oder schwere Kreislaufreaktionen auftreten. Andererseits birgt oft gerade das perioperative Absetzen von Medikamenten die größere Gefahr. Der Anteil ambulant durchgeführter Operationen hat in den letzten Jahren stark zugenommen und wird voraussichtlich auch in Zukunft zunehmen. Seit Einführung der Fallpauschalen (in der Schweiz bevorstehend) wird der Patient in der Regel erst am Vortag der Operation stationär aufgenommen. Somit sind sowohl zuweisende Ärzte als auch Anästhesisten und Operateure gezwungen, sich frühzeitig mit Fragen der perioperativen Pharmakotherapie auseinanderzusetzen. Dieser Übersichtsartikel behandelt das Management der wichtigsten Medikamentenklassen während der perioperativen Phase. Neben kardial und zentral wirksamen Medikamenten und Wirkstoffen, welche auf die Hämostase und das endokrine System wirken, werden Spezialfälle wie Immunsuppressiva und Phytopharmaka behandel
Выбор оптимальных технических решений для улавливания углеводородных паров от резервуарных парков нефти
San Francisco, CA - US
Administration of Endotoxin, Tumor Necrosis Factor, or Interleukin 1 to Rats Activates Skeletal Muscle Branched-Chain α-Keto Acid Dehydrogenase
Protein catabolic states (i.e., sepsis and trauma) are thought to be associated with accelerated oxidation of branched-chain amino acids (BCAA). Branched-chain α-keto acid dehydrogenase (BCKAD), the rate-limiting enzyme for BCAA oxidation by muscle, is regulated by phosphorylation/dephosphorylation. Skeletal muscle BCKAD was only 2-4% active in control rats. Intravenous injection of Salmonella enteritidis endotoxin (0.25-10 mg/kg) did not change total BCKAI) activity, but increased the percent active enzyme in muscle three- to four-fold in 4-6 h. Identical results were observed in adrenalectomized rats pretreated with one dose of α-methylprednisolone (2.5 mg/kg i.p.) 30-60 min before saline or endotoxin injection, indicating that endotoxin\u27s effect was not mediated by hypersecretion of adrenal hormones. Cortisone pretreatment of normal rats (100 mg/kg per d) for 2 d prevented endotoxin-induced activation of muscle BCKAD, suggesting that endogenous secretion products mediated BCKAD activation by endotoxin. Human recombinant tumor necrosis factor-α and/or IL-1β or α (50 μg/kg) increased muscle BCKAD activation two- to fourfold in normal rats 4-6 h after intravenous injection. We conclude that cytokine-mediated activation of muscle BCKAD may contribute to accelerated BCAA oxidation in septicemia
Remifentanil does not impair left ventricular systolic and diastolic function in young healthy patients
Background Experimental studies and investigations in patients with cardiac diseases suggest that opioids at clinical concentrations have no important direct effect on myocardial relaxation and contractility. In vivo data on the effect of remifentanil on myocardial function in humans are scarce. This study aimed to investigate the effects of remifentanil on left ventricular (LV) function in young healthy humans by transthoracic echocardiography (TTE). We hypothesized that remifentanil does not impair systolic, diastolic LV function, or both. Methods Twelve individuals (aged 18-48 yr) without any history or signs of cardiovascular disease and undergoing minor surgical procedures under general anaesthesia were studied. Echocardiographic examinations were performed in the spontaneously breathing subjects before (baseline) and during administration of remifentanil at a target effect-site concentration of 2 ng ml−1 by target-controlled infusion. Analysis of systolic function focused on fractional area change (FAC). Analysis of diastolic function focused on peak early diastolic velocity of the mitral annulus (e′) and on transmitral peak flow velocity (E). Results Remifentanil infusion at a target concentration of 2 ng ml−1 did not affect heart rate or arterial pressure. There was no evidence of systolic or diastolic dysfunction during remifentanil infusion, as the echocardiographic measure of systolic function (FAC) was similar to baseline, and measures of diastolic function remained unchanged (e′) or improved slightly (E). Conclusion Continuous infusion of remifentanil in a clinically relevant concentration did not affect systolic and diastolic LV function in young healthy subjects during spontaneous breathing as indicated by TT
Temperature dependence of absorption in photorefractive iron-doped lithium niobate crystals
We present experimental data showing a significant dependence of light absorption on temperature in photorefractive LiNbO3:Fe crystals. The results are successfully explained by assuming that the widths of the Fe2+ absorption bands in the visible and in the infrared spectral region depend on temperature. The findings are of relevance for thermal fixing of holograms. Furthermore, a temperature-induced increase of the infrared absorption is promising for improved infrared recording. (C) 2002 American Institute of Physics
Incorporating a gender lens into nutrition and health-related policies in Fiji: analysis of policies and stakeholder perspectives
Background: Gender equality, zero hunger and healthy lives and well-being for all, are three of the Sustainable Development Goals (SDGs) that underpin Fiji’s National Development Plan. Work towards each of these goals contributes to the reduction of non-communicable diseases (NCDs). There are gender differences in NCD burden in Fiji. It is, however, unclear whether a gender lens could be more effectively included in nutrition and health-related policies. Methods: This study consisted of three components: (i) a policy content analysis of gender inclusion in nutrition and health-related policies (n = 11); (ii) policy analysis using the WHO Gender Analysis tool to identify opportunities for strengthening future policy; and (iii) informant interviews (n = 18), to understand perceptions of the prospects for gender considerations in future policies. Results: Gender equality was a goal in seven policies (64%); however, most focused on women of reproductive age. One of the policies was ranked as gender responsive. Main themes from key informant interviews were: 1) a needs-based approach for the focus on specific population groups in policies; 2) gender-related roles and responsibilities around nutrition and health; 3) what is considered “equitable” when it comes to gender, nutrition, and health; 4) current considerations of gender in policies and ideas for further gender inclusion; and 5) barriers and enablers to the inclusion of gender considerations in policies. Informants acknowledged gender differences in the burden of nutrition-related NCDs, yet most did not identify a need for stronger inclusion of gender considerations within policies. Conclusions: There is considerable scope for greater inclusion of gender in nutrition and health-related policies in Fiji. This could be done by: 1) framing gender considerations in ways that are actionable and inclusive of a range of gender identities; 2) undertaking advocacy through actor networks to highlight the need for gender-responsive nutrition and health-related policies for key stakeholder groups; 3) ensuring that data collected to monitor policy implementation is disaggregated by sex and genders; and 4) promoting equitable participation in nutrition related issues in communities and governance processes. Action on these four areas are likely critical enablers to more gender equitable NCD reduction in Fiji
Perioperative administration of fibrinogen does not increase adverse cardiac and thromboembolic events after cardiac surgery
Background Although infusion of fibrinogen concentrate is increasingly used in bleeding patients after cardiac surgery, safety data are scarce. We aimed to evaluate the effect of perioperative administration of fibrinogen concentrate on postoperative morbidity and mortality in patients undergoing cardiac surgery. Methods During a 2 yr study period, 991 patients underwent cardiac surgery at a single university centre and were eligible for propensity score (PS) matching. We matched 190 patients with perioperative infusion of fibrinogen concentrate (median dose 2 g) with 190 controls without fibrinogen administration. After PS matching, crude outcome was analysed. Further, a multivariate logistic regression including additional risk factors for adverse outcome was performed. The primary endpoint was a composite of mortality and the occurrence of major cardiac and thromboembolic events within 1 yr. Secondary outcomes included mortality after 30 days and 1 yr and the composite of mortality and adverse events after 30 days. Results The administration of fibrinogen concentrate was not associated with an increased risk for mortality and thromboembolic or cardiac events within 1 yr after cardiac surgery [unadjusted hazard ratio (HR) 0.91; 95% confidence interval (CI) 0.55-1.49; P=0.697]. When using multivariate logistic regression model, the HR for adverse outcome in patients with administration of fibrinogen concentrate was 0.57 (95% CI 0.25-1.17; P=0.101). Similarly, the administration of fibrinogen concentrate did not adversely affect the secondary outcomes when applying unadjusted and multivariate regression analyses. Conclusions Our study strongly suggests that the administration of fibrinogen concentrates at low dose is not associated with thromboembolic complications or adverse outcomes after cardiac surger
Regulation of branched-chain amino acid oxidation in isolated muscles, nerves and aortas of rats
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