186 research outputs found

    A measurement of the 4He(g,n) reaction from 23 < Eg < 70 MeV

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    A comprehensive set of 4He(g,n) absolute cross-section measurements has been performed at MAX-lab in Lund, Sweden. Tagged photons from 23 < Eg < 70 MeV were directed toward a liquid 4He target, and neutrons were identified using pulse-shape discrimination and the Time-of-flight Technique in two liquid-scintillator detector arrays. Seven-point angular distributions have been measured for fourteen photon energies. The results have been subjected to complementary Transition-coefficient and Legendre-coefficient analyses. The results are also compared to experimental data measured at comparable photon energies as well as Recoil-Corrected Continuum Shell Model, Resonating Group Method, and Effective Interaction Hyperspherical-Harmonic Expansion calculations. For photon energies below 29 MeV, the angle-integrated data are significantly larger than the values recommended by Calarco, Berman, and Donnelly in 1983.Comment: 16 pages, 14 figures, some more revisions, submitted to Physical Review

    Thiol-Functionalized Mesoporous Silica for Effective Trap of Mercury in Rats

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    The chance of exposure to heavy metal for human being rises severely today due to the increasing water contamination and air pollution. Here, we prepared a series of thiol-functionalized mesoporous silica as oral formulation for the prevention and treatment of heavy metal poisoning. The successful incorporation of thiol was verified by the FTIR spectra. SBA15-SH-10 was used for the study as it is of uniform mesopores and fine water dispersibility. In simulated gastrointestinal fluid, the thiol-functionalized mesoporous silica can selectively capture heavy metal, showing a very high affinity for inorganic mercury (II). The blood and urine mercury levels of rats fed with a diet containing Hg (II) and material were significantly lower than those of rats fed with the metal-rich diet only. On the contrary, the mercury content in fecal excretion of the treatment group increased more than twice as much as that of the control group. This result indicated that SBA15-SH-10 could effectively remove mercury (II) in vivo and the mercury loaded on SBA15-SH-10 would be excreted out. Hence, SBA15-SH-10 has potential application in preventing and treating heavy metal poisoning via digestive system

    Mechano-Electric Feedback in the Fish Heart

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    Mechanoelectric feedback (MEF) describes the modulation of electrical activity by mechanical activity. This may occur via the activation of mechanosensitive ion channels (MSCs). MEF has not previously been investigated in fish ventricular tissue even though fish can greatly increase ventricular end diastolic volume during exercise which should therefore provide a powerful mechanical stimulus for MEF.When the ventricles of extrinsically paced, isolated working trout hearts were dilated by increasing afterload, monophasic action potential (MAP) duration was significantly shortened at 25% repolarisation, unaltered at 50% repolarisation and significantly lengthened at 90% repolarisation. This observation is consistent with the activation of cationic non-selective MSCs (MSC(NS)s). We then cloned the trout ortholog of TRPC1, a candidate MSC(NS) and confirmed its presence in the trout heart.Our results have validated the use of MAP technology for the fish heart and suggest that, in common with amphibians and mammals, MEF operates in fish ventricular myocardium, possibly via the activation of mechanosensitive TRPC1 ion channels

    A prática da enfermeira em auditoria em saúde

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    O objetivo da investigação foi conhecer a prática da enfermeira em auditoria em saúde. A concepção de análise adotada foi a da hermenêutica-dialética, e foi desenvolvida em três lócus: a auditoria interna de uma organização hospitalar; a auditoria externa de um comprador privado de serviços de saúde, e o sistema de auditoria do âmbito estadual do Sistema Único de Saúde (SUS), na Bahia. Foram entrevistadas nove enfermeiras auditoras. Na auditoria do SUS, as enfermeiras expressaram satisfação no exercício desta prática e valorização de seu papel profissional. Na auditoria privada - interna e externa às organizações de saúde - as ações das enfermeiras se direcionam para atender aos interesses de seus contratantes, e pouco se relacionam com a assistência prestada pela equipe de enfermagem e com as necessidades dos usuários dos serviços.El objetivo de la investigación es conocer la práctica de la enfermera en la auditoría de salud. La concepción de análisis adoptada fue la de la hermenéutica-dialéctica, y se desarrolló en tres locales: la auditoría interna de una organización hospitalaria, la auditoría externa de un comprador privado de servicios de salud y el sistema de auditoría del ámbito estatal del Sistema Único de Salud (SUS) en Bahía, Brasil. Fueron entrevistadas nueve enfermeras auditoras. En la auditoría del SUS, las enfermeras expresaron satisfacción en el ejercicio de esta práctica y en la valorización de su papel profesional. En la auditoría privada - interna y externa a las organizaciones de salud - las acciones de las enfermeras están dirigidas a atender los intereses de sus contratantes, y poco se relacionan con la asistencia prestada por el equipo de enfermería y con las necesidades de los usuarios de los servicios.The objective of this investigation was to identify nurses' practice in heath audit. The hermeneutic-dialectic method was used for the analysis. The study was performed in three loci: the internal audit service of a hospital; the external audit service of a private health service buyer, and the state audit service of the public health system (SUS, acronym in Portuguese for Sistema Único de Saúde - Unique Health System), in Bahia. Nine audit nurses were interviewed. In the SUS audit, the nurses report being fulfilled with their practice and with the valorization of their professional role. In the private audit - both inside and outside of health organizations - the nurses' activities are focused on meeting the interests of their contractors, and do not get much involved with the care delivered by the nursing team and with the needs of service users

    Restitution analysis of alternans and its relationship to arrhythmogenicity in hypokalaemic Langendorff-perfused murine hearts

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    Alternans and arrhythmogenicity were studied in hypokalaemic (3.0 mM K+) Langendorff-perfused murine hearts paced at high rates. Epicardial and endocardial monophasic action potentials were recorded and durations quantified at 90% repolarization. Alternans and arrhythmia occurred in hypokalaemic, but not normokalaemic (5.2 mM K+) hearts (P < 0.01): this was prevented by treatment with lidocaine (10 μM, P < 0.01). Fourier analysis then confirmed transition from monomorphic to polymorphic waveforms for the first time in the murine heart. Alternans and arrhythmia were associated with increases in the slopes of restitution curves, obtained for the first time in the murine heart, while the anti-arrhythmic effect of lidocaine was associated with decreased slopes. Thus, hypokalaemia significantly increased (P < 0.05) maximal gradients (from 0.55 ± 0.14 to 2.35 ± 0.67 in the epicardium and from 0.67 ± 0.13 to 1.87 ± 0.28 in the endocardium) and critical diastolic intervals (DIs) at which gradients equalled unity (from −2.14 ± 0.52 ms to 50.93 ± 14.45 ms in the epicardium and from 8.14 ± 1.49 ms to 44.64 ± 5 ms in the endocardium). While treatment of normokalaemic hearts with lidocaine had no significant effect (P > 0.05) on either maximal gradients (0.78 ± 0.27 in the epicardium and 0.83 ± 0.45 in the endocardium) or critical DIs (6.06 ± 2.10 ms and 7.04 ± 3.82 ms in the endocardium), treatment of hypokalaemic hearts with lidocaine reduced (P < 0.05) both these parameters (1.05 ± 0.30 in the epicardium and 0.89 ± 0.36 in the endocardium and 30.38 ± 8.88 ms in the epicardium and 31.65 ± 4.78 ms in the endocardium, respectively). We thus demonstrate that alternans contributes a dynamic component to arrhythmic substrate during hypokalaemia, that restitution may furnish an underlying mechanism and that these phenomena are abolished by lidocaine, both recapitulating and clarifying clinical findings
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