The ferromagnet (FM)-normal metal (NM) interface plays an important role in spintronics devices. By the use of multilayers the details of interdiffusion and film quality (e.g. strain) can be studied ...by NMR utilizing nuclei in both the FM and NM. We have studied the interfaces of room temperature MBE grown Co-Al, Co-Ag, and Co-Cu multilayers. 59Co NMR reveals that Co-Ag and Co-Cu both have relatively sharp interfaces. Whereas Co-Al shows considerable surface roughness and interdiffusion at the interfaces. 27Al NMR spectra exhibit substantial quadrupolar broadening due to interfacial diffusion which decreases with Al layer thickness. For Cu-FM layers, 63Cu NMR satellite peaks and line broadening have been previously associated with RKKY-like interactions between FM and non-FM layers1,2. In this work, the 63Cu NMR line shape is studied as a function of temperature and magnetic field. The correlation between the line shape and the RKKY-like interaction is discussed. 1 Q.Y. Jin, Phys. Rev. Lett. B72, 768 (1994).
Recent work, both zero-field and high-field 59Co NMR, has confirmed nano-scale phase separation in La_1-xSr_xCoO_3 (LSCO) for x values( 0.1lexle0.5 ). However, 59Co provides limited information on ...the LSCO phase diagram since short relaxation times limit measurements to temperatures below 25 K. 139La spectra, x values 0.1 to 0.3, at fields 10 to 22 T, provide further detailed information on the evolution of the phases with temperature through the Curie point Tc ~240 K. The hyperfine couplings permit identification of the various phases as ferromagnetic ( FM), spin-glass (SG),and low-spin (LS). The data suggests that spin state conversions occur for increasing temperature changing the relative concentration of the different phases. The results show that the previously suggested phase diagram must be modified to capture the intricate changes in properties that occur as a function of temperature.
The structure of both quasi-real and highly virtual photons is investigated using the reaction \({\rm e^+e^-}\rightarrow{\rm e^+e^-}\mu^+\mu^-\), proceeding via the exchange of two photons. The ...results are based on the complete OPAL dataset taken at \({\rm e^+e^-}\) centre-of-mass energies close to the mass of the Z boson. The QED structure function \(F^\gamma _2\) and the differential cross-section \({\rm d}\sigma/{\rm d}x\) for quasi-real photons are obtained as functions of the fractional momentum x from the muon momentum which is carried by the struck muon in the quasi-real photon for values of \(Q^2\) ranging from 1.5 to 400 GeV\(^2\). The differential cross-section \({\rm d}\sigma/{\rm d}x\) for highly virtual photons is measured for \(1.5< Q^2 < 30\) GeV\(^2\) and \(1.5< P^2 < 20\) GeV\(^2\), where \(Q^2\) and \(P^2\) are the negative values of the four-momentum squared of the two photons such that \(Q^2>P^2\). Based on azimuthal correlations the QED structure functions \(F^\gamma _{\rm A}\) and \(F^\gamma _{\rm B}\) for quasi-real photons are determined for an average \(Q^2\) of 5.4 GeV\(^2\).
$Ni_{50-x}Co_{x}Mn_{40}Sn_{10}$ shape memory alloys in the approximate range
$5 \le x \le 10$ display desirable properties for applications as well as
intriguing magnetism. These off-stoichiometric ...Heusler alloys undergo a
martensitic phase transformation at a temperature $T_{M}$ of 300 - 400 K, from
ferromagnetic (F) to nonferromagnetic, with unusually low thermal hysteresis
and a large change in magnetization. The low temperature magnetic structures in
the martensitic phase of such alloys, which are distinctly inhomogeneous, are
of great interest but are not well understood. Our present use of spin echo
NMR, in the large hyperfine fields at $^{55}Mn$ sites, provides compelling
evidence that nanoscale magnetic phase separation into F and antiferromagnetic
(AF) regions occurs below $T_{M}$ in alloys with x in the range 0 to 7. At
finite Co substitution the F regions are found to be of two distinct types,
corresponding to high and low local concentrations of Co on Ni sites. Estimates
of the size distributions of both the F and AF nanoregions have been made. At x
= 7 the AF component is not long-range ordered, even below 4 K, and is quite
different to the AF component found at x = 0; by x = 14 the F phase is
completely dominant. Of particular interest, we find, for x = 7, that field
cooling leads to dramatic changes in the AF regions. These findings provide
insight into the origins of magnetic phase separation and superparamagnetism in
these complex alloys, particularly their intrinsic exchange bias, which is of
considerable current interest.
A radioimmunoassay technique using a double antibody procedure for human serum thyroglobulin (HTg) is described. Only antigen labeling with iodine-125 is performed extemporaneously, the other ...reagents being purchased commercially. Quality criteria were: sensitivity (2 microgram/l), interassay reproducibility (coefficient of variance, C.V. = 11%) and specificity are comparable with those of previously published techniques. Normal limits for serum HTg concentrations were established on the basis of 65 assays (33.0 +/- 21.20 microgram/l). In 69 subjects exhibiting goiters and cold nodules, the values observed were considerably higher and more dispersed (81 +/- 57 microgram/l); the same observation was made for the the cases of Basedow's disease studied. Patients who had undergone thyroid ablation for thyroid cancer exhibited a low or nondemonstrable HTg concentration, except for seven subjects showing osseous and/or pulmonary functionally active metastases of a differentiated cancer whose HTg levels were significantly higher (300-400 microgram/l). These results concur with several previous reports in emphasizing the interest of assaying serum HTg during the surveillance of differentiated cancers of the thyroid.
Consumer empowerment in dermatology Hoch, Heather E; Busse, Kristine L; Dellavalle, Robert P
Dermatologic clinics,
04/2009, Letnik:
27, Številka:
2
Journal Article
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Odprti dostop
Health care consumers increasingly confront and collaborate with medical providers. This article describes recent developments in health care consumer activism including dermatology disease advocacy ...and efforts to improve dermatologist-patient interactions.
With a background of 14 years of psychiatric activity in India, the author examines whether psychotherapy as ‘aid for development’ has significance not only for the individual, but also, in a ...collective sense, for a ‘developing country’. Though theoretically the question can be positively answered, any practical implementation comes up against numerous material, personal and ideological obstacles. Means of communication and therapeutic methods adequate for little-emancipated, often illiterate patients, and criteria for selection of suitable cases are discussed. Not only the developing country, but also the therapist himself is likely to gain through psychotherapeutic activity in a setting of this kind.
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