FREQUENCY-DOMAIN THERMO-MAGNET MEMORY EFFECT IN THE CO75-XFEXSI15B10 ALLOYS

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Magnetic couplings in CoFe2O4/FeCo-FeO core-shell nanoparticles

CoFe2O4/FeCo-FeO core-shell nanoparticles with an average particle size of about 4.3 nm were prepared by reducing nanoparticles of superparamagnetic cobalt-ferrite under hydrogen and oxygen atmospheres. The low temperature magnetic hysteresis showed an interesting behavior which has only been observed in thin film multilayer systems. At low magnetic fields H (< 0.2 kOe) the behavior is dominated by the magnetic structure of the magnetically soft shell while for higher values of 11 the exchange-spring core-shell coupling plays a major role. A particle model which is coherent with the observed magnetic behavior has been also proposed. (C) 2014 Elsevier B.V. All rights reserve

Study of lipid profile in adult women with acne

Marisa Gonzaga da Cunha,1 Anna Luiza Fonseca Batista,1 Marzia Silva Macedo,1 Carlos D&rsquo;Aparecida Santos Machado Filho,1 Fernando Luiz Affonso Fonseca2 1Dermatology Department, Faculdade de Medicina do ABC (FMABC), Santo Andr&eacute;, S&atilde;o Paulo, Brazil; 2Biological Sciences Department, Universidade Federal de S&atilde;o Paulo (UNIFESP), Diadema, S&atilde;o Paulo, Brazil Objective: The aim of this study was to establish the lipid profile of female patients with acne in the Acne-in-Adult-Women Ambulatory Care Clinic in order to observe the prevalence of dyslipidemia in those patients. Methods: This is a retrospective transversal study that evaluated the medical records of 416 patients who attended at the Acne-in-Adult-Women Ambulatory Care Clinic, at the Dermatology Department, Faculdade de Medicina do ABC, Santo Andr&eacute;, S&atilde;o Paulo, Brazil, in the year 2012. Relevant data included age and clinical classification of acne. The lipid profile was analyzed according to the results of laboratory tests ordered during outpatient visits, which included total and fractionated cholesterol levels and triglycerides. Results: The epidemiological study sample was of 219 patients, with ages ranging from 21 to 61 years (mean of 32.23 years). The predominant clinical grade was papule-pustule acne (grade II) with 156 patients (71%). Regarding the lipid profile of the patients, there was a high increase in total cholesterol levels in 17.35% of the cases. High-density lipoprotein levels were low in 11.42% of the patients, with normal prevalence in 194 subjects. Low-density lipoprotein levels were normal in most patients (60.27%). Very-low-density lipoprotein values were normal in almost all patients (94.06%) and increased in only 13 patients (5.94%). Only 18 patients presented high levels of triglycerides (8.22%). Conclusion: The conclusion was that patients with grades II and III acne are more likely to have total cholesterol and low-density lipoprotein altered. A correct and early diagnosis can be an important measure for the prevention of the metabolic syndrome in these patients. Keywords: acne, hyperandrogenism, dyslipidemia, cholesterol, triglyceride

Effects of Ru doping on the transport and magnetic properties of a La1.32Sr1.68Mn2-yRuyO7 layered manganite system

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)The low temperature magnetization, specific heat, electrical resistance and magnetoresistance have been studied for the Ru-doped La1.32Sr1.68Mn2-yRuyO7 (y = 0.0, 0.04, 0.08 and 0.15) layered manganite system. The undoped compound (y = 0.0) shows a sharp ferromagnetic transition (T-C) accompanied by a metal-insulator transition (T-MI) at 118 K. The Ru substitution decreases the T-C and T-MI temperatures significantly. The temperature dependence of specific heat measurement confirms the decrease in T-C by observing the anomaly corresponding to T-C. The decreased effective moments from 3.48 mu(B) for the undoped compound to 1.82 mu(B) for the highly doped compound at 5 K indicates the Ru substitution weakens the ferromagnetic order in the low temperature regime and reduces the number of Mn pairs in the highly doped sample. The field dependence of magnetization measurements exhibits an enhancement of the coercive field with increased Ru concentration and gives evidence for the mixed magnetic phase for the highly doped compound. For the undoped sample, a large negative magnetoresistance of 300% at T-C and 128% at 4.2 K in a 5 T field were observed. The magnetoresistance ratio decreases gradually with increasing Ru substitution. We find that the doped Ru in the Mn site drives the layered manganite system towards a magnetically mixed state. The effects of Ru doping in the transport and magnetic properties will be explained by the antiferromagnetically coupled Ru and Mn sublattices.2223Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Third World Academy of Sciences (TWAS), ItalyFundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)CNPq [470940/2007-7]APQ1-FAPERJ [E26/170.717/2007]Pronex-FAPERJ [E-26/171.165/2003]Cientistas do Estado-FAPERJ [E-26/102.700/2008