565 research outputs found
Pressure-induced Colossal Magnetocaloric Effect In Mnas.
To present day, the maximum magnetocaloric effect (MCE) at room temperature for a magnetic field change of 5 T is 40 J/(kg K) for MnAs. In this Letter we present colossal MCE measurements on MnAs under pressure, reaching values up to 267 J/(kg K), far greater than the magnetic limit arising from the assumption of magnetic field independence of the lattice and electronic entropy contributions. The origin of the effect is the contribution to the entropy variation coming from the lattice through the magnetoelastic coupling.9323720
The Magnetic And Magnetocaloric Properties Of Gd 5ge 2si 2 Compound Under Hydrostatic Pressure
The Gd5 Ge2 Si2 compound presents a giant magnetocaloric effect with transition temperature at around 276 K and is a very good candidate for application as an active regenerator material in room temperature magnetic refrigerators. Recently it has been shown that pressure induces a colossal magnetocaloric effect in MnAs, a material that presents a giant magnetocaloric effect and a strong magnetoelastic coupling, as also happens with the Gd5 Ge2 Si2 compound. This motivated a search of the colossal effect in the Gd5 Ge2 Si2 compound. This work reports our measurements on the magnetic properties and the magnetocaloric effect of Gd5 Ge2 Si2 under hydrostatic pressures up to 9.2 kbar and as a function of temperature. Contrary to what happens with MnAs, pressure increases the Curie temperature of the compound, does not affect the saturation magnetization and decreases markedly its magnetocaloric effect. © 2005 American Institute of Physics.9710Pecharsky, V.K., Gschneidner Jr., K.A., (1977) Phys. Rev. Lett., 78, p. 4494Pecharsky, V.K., Gschneidner Jr., K.A., (2001) Adv. Mater. (Weinheim, Ger.), 13, p. 683Morellon, L., Algarabel, P.A., Ibarra, M.R., Blasco, J., García-Landa, B., Arnold, Z., Albertini, F., (1998) Phys. Rev. B, 58, p. 14721Del Moral, A., Algarabel, P.A., Arnaudas, J.I., Benito, L., Ciria, M., De La Fuente, C., García-Landa, B., De Teresa, J.M., (2002) J. Magn. Magn. Mater., 242-245, p. 788Pecharsky, A.O., Gschneidner Jr., K.A., Pecharsky, V.K., (2003) J. Magn. Magn. Mater., 267, p. 60Pecharsky, A.O., Gschneidner Jr., K.A., Pecharsky, V.K., (2003) J. Appl. Phys., 93, p. 4722Gama, S., De Campos, A., Carvalho Magnus, A.G., Coelho, A.A., Gandra, F.C.G., Von Ranke, P.J., De Oliveira, N.A., (2004) Phys. Rev. Lett., 93, p. 237202Von Ranke, P.J., De Oliveira, N.A., Gama, S., (2004) J. Magn. Magn. Mater., 277, p. 78Pecharsky, V.K., Gschneidner Jr., K.A., (1998) Adv. Cryog. Eng., 43, p. 1729Menyuk, N., Kafalas, J.A., Dwight, K., Goodenough, J.B., (1969) Phys. Rev., 177, p. 942Morellon, L., Arnold, Z., Algarabel, P.A., Magen, C., Ibarra, M.R., Skorodhod, Y., (2004) J. Phys.: Condens. Matter, 16, p. 162
Acoustic Detection Of The Magnetocaloric Effect: Application To Gd And Gd5.09 Ge2.03 Si1.88
In this paper we present a simple method for the determination of the total magnetocaloric effect based on the acoustic detection of the adiabatic temperature rise caused by the application of an ac magnetic field of small amplitude. The continuous scanning of a superimposed dc magnetic field allows, by numerical integration, the determination of large temperature variations caused by magnetic field steps from zero to tens of kOe. Absolute values of temperature rise are easily acquired after the calibration of the microphone signal using an appropriate reference sample. Once the calibration is done, no further information about the sample's thermal properties is necessary since the measured signal is directly proportional to the temperature variation. Measurements were made in Gd and Gd5.09 Ge2.03 Si1.88 samples in the temperature range from 240 to 320 K. The technique shows to be suitable for the investigation of materials undergoing both purely magnetic phase transitions, as in the case of Gd, and magnetic-crystallographic first-order ones, as observed for Gd5.09 Ge2.03 Si1.88. Besides the ability to determine the temperature variation due to a large magnetic field step through the continuous scanning of the magnetic field, the technique is also very suitable for measuring the magnetocaloric effect under very small magnetic field steps since it has sensitivity below millikelvin. Moreover, it is able to detect temperature variations in very small amount of sample, leading to its potential application in magnetocaloric thin films. © 2009 The American Physical Society.8013Foldeaki, M., Schnelle, W., Gmelin, E., Benard, P., Koszegi, B., Giguere, A., Chahine, R., Bose, T.K., (1997) J. Appl. Phys., 82, p. 309. , 10.1063/1.365813Pecharsky, V.K., Gschneidner, Jr.K.A., (1999) J. Appl. Phys., 86, p. 565. , 10.1063/1.370767Gopal, B.R., Chahine, R., Bose, T.K., (1997) Rev. Sci. Instrum., 68, p. 1818. , 10.1063/1.1147999Pecharsky, V.K., Gschneidner, Jr.K.A., (1999) J. Magn. Magn. Mater., 200, p. 44. , 10.1016/S0304-8853(99)00397-2Pecharsky, V.K., Gschneidner, Jr.K.A., (1997) Phys. Rev. Lett., 78, p. 4494. , 10.1103/PhysRevLett.78.4494Otowski, W., Glorieux, C., Hofman, R., Thoen, J., (1993) Thermochim. Acta, 218, p. 123. , 10.1016/0040-6031(93)80416-8Gopal, B.R., Chahine, R., Földeàki, M., Bose, T.K., (1995) Rev. Sci. Instrum., 66, p. 232. , 10.1063/1.1145264Rosencwaig, A., Gersho, A., (1976) J. Appl. Phys., 47, p. 64. , 10.1063/1.322296Pecharsky, V.K., Gschneidner, Jr.K.A., (2001) Adv. Mater., 13, p. 683. , 10.1002/1521-4095(200105)13:93.0.CO;2-OVon Ranke, P.J., De Oliveira, N.A., Gama, S., (2004) J. Magn. Magn. Mater., 277, p. 78. , 10.1016/j.jmmm.2003.10.013Carvalho, A.M.G., Alves, C.S., Campos, A., Coelho, A.A., Gama, S., Gandra, F.C.G., Von Ranke, P.J., Oliveira, N.A., (2005) J. Appl. Phys., 97, pp. 10M320. , 10.1063/1.1860932Pecharsky, A.O., Gschneidner, Jr.K.A., Pecharsky, V.K., (2003) J. Magn. Magn. Mater., 267, p. 60. , 10.1016/S0304-8853(03)00305-6Gama, S., Alves, C.S., Coelho, A.A., Ribeiro, C.A., Persiano, A.I.C., Silva, D., (2004) J. Magn. Magn. Mater., 272-276, p. 848. , 10.1016/j.jmmm.2003.12.1260Pires, M.J.M., Carvalho, A.M.G., Gama, S., Da Silva, E.C., Coelho, A.A., Mansanares, A.M., (2005) Phys. Rev. B, 72, p. 224435. , 10.1103/PhysRevB.72.224435Glorieux, C., Thoen, J., Bednarz, G., White, M.A., Geldart, D.J.W., (1995) Phys. Rev. B, 52, p. 12770. , 10.1103/PhysRevB.52.12770Bednarz, G., Geldart, D.J.W., White, M.A., (1993) Phys. Rev. B, 47, p. 14247. , 10.1103/PhysRevB.47.14247Yu. Dan'Kov, S., Tishin, A.M., Pecharsky, V.K., Gschneidner, Jr.K.A., (1998) Phys. Rev. B, 57, p. 3478. , 10.1103/PhysRevB.57.3478Glorieux, C., Caerels, J., Thoen, J., (1996) J. Appl. Phys., 80, p. 3412. , 10.1063/1.363208Pecharsky, V.K., Gschneidner, Jr.K.A., (1999) J. Appl. Phys., 86, p. 6315. , 10.1063/1.371734Giguere, A., Foldeaki, M., Ravi Gopal, B., Chahine, R., Bose, T.K., Frydman, A., Barclay, J.A., (1999) Phys. Rev. Lett., 83, p. 2262. , 10.1103/PhysRevLett.83.2262Yue, M., Zhang, J., Zeng, H., Chen, H., Liu, X.B., (2006) J. Appl. Phys., 99, pp. 08Q104. , 10.1063/1.2158971Tocado, L., Palacios, E., Burriel, R., (2006) J. Therm Anal. Calorim., 84, p. 213. , 10.1007/s10973-005-7180-zGschneidner, Jr.K.A., Pecharsky, V.K., Brück, E., Duijn, H.G.M., Levin, E.M., (2000) Phys. Rev. Lett., 85, p. 4190. , 10.1103/PhysRevLett.85.419
New Multicomponent Forms of the Antiretroviral Nevirapine with Improved Dissolution Performance
In the pharmaceutical area, some drugs exhibit physicochemical properties that adversely affect the formulation processes for bioavailability and effectiveness. Nevirapine (NVP) is an antiretroviral drug that presents low aqueous solubility, which directly impacts its bioavailability. Among all possible modifications, multicomponent crystals, such as cocrystals and eutectic compositions, have been successfully used to improve the solubility of drugs. In this work, the propensity of the formation of multicomponent systems of NVP with seven possible coformers were predicted and tested: salicylic acid (SA), 3-hydroxybenzoic acid (3HBZC), 4-hydroxybenzoic acid (4HBZC), saccharin (SAC), theophylline (THEO), caffeine (CAF), and urea (URE). Results indicate that NVP-SA, NVP-SAC, NVP-3HBZC, and NVP-4HBZC are cocrystals, whereas NVP-THEO and NVP-CAF are eutectic materials, and NVP-URE is a solid physical mixture. A temperature-dependent disorder behavior was identified for NVP-SA cocrystal. Dissolution studies for the eutectic materials are reported, evidencing that these materials exhibit a significant increase in NVP dissolution kinetics.Fil: Costa, Rogeria Nunes. Universidade Federal de Sao Paulo; BrasilFil: Reviglio, Ana Lucía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; ArgentinaFil: Siedler, Sana. Universidade Federal de Santa Catarina; BrasilFil: Cardoso, Simone G.. Universidade Federal de Santa Catarina; BrasilFil: Garro Linck, Yamila. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; ArgentinaFil: Monti, Gustavo Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; ArgentinaFil: Carvalho, Alexandre Magnus G.. Centro Nacional de Pesquisa em Energia e Materiais; BrasilFil: Resende, Jackson A. L. C.. Universidade Federal do Mato Grosso do Sul; BrasilFil: Chaves, Marcelo H. C.. Fundación Oswaldo Cruz; BrasilFil: Rocha, Helvético Vinícius Antunes. Fundación Oswaldo Cruz; BrasilFil: Choquesillo Lazarte, Duane. Consejo Superior de Investigaciones Científicas; España. Universidad de Granada; EspañaFil: Infantes, Lourdes. Consejo Superior de Investigaciones Científicas; España. Instituto de Química Física Rocasolano; EspañaFil: Cuffini, Silvia Lucia. Universidade de Sao Paulo; Brasi
Genotype and phenotype landscape of MEN2 in 554 medullary thyroid cancer patients: the BrasMEN study
Multiple endocrine neoplasia type 2 (MEN2) is an autosomal dominant genetic disease caused by RET gene germline mutations that is characterized by medullary thyroid carcinoma (MTC) associated with other endocrine tumors. Several reports have demonstrated that the RET mutation profile may vary according to the geographical area. In this study, we collected clinical and molecular data from 554 patients with surgically confirmed MTC from 176 families with MEN2 in 18 different Brazili an centers to compare the type and prevalence of RET mutations with those from other countries. The most frequent mutations, classified by the number of families affected, occur in codon 634, exon 11 (76 families), followed by codon 918, exon 16 (34 families: 26 with M918T and 8 with M918V) and codon 804, exon 14 (22 families: 15 with V804M and 7 with V804L). When compared with other major published series from Europe, there are several similarities and some differences. While the mutations in codons C618, C620, C630, E768 and S891 present a similar prevalence, some mutations have a lower prevalence in Brazil, and others are found mainly in Brazil (G533C and M918V). These results reflect the singular proportion of European, Amerindian and African ancestries in the Brazilian mosaic genome83289298CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DO RIO GRANDE DO SUL - FAPERGSSem informaçãoSem informação2006/60402-1; 2010/51547-1; 2013/01476-9; 2014/06570-6; 2009/50575-4; 2010/51546-5; 2012/21942-116/2551-0000482-
Use of anticoagulants and antiplatelet agents in stable outpatients with coronary artery disease and atrial fibrillation. International CLARIFY registry
Adherence to treatment in allergic rhinitis using mobile technology. The MASK Study
Background: Mobile technology may help to better understand the adherence to treatment. MASK-rhinitis (Mobile Airways Sentinel NetworK for allergic rhinitis) is a patient-centred ICT system. A mobile phone app (the Allergy Diary) central to MASK is available in 22 countries. Objectives: To assess the adherence to treatment in allergic rhinitis patients using the Allergy Diary App. Methods: An observational cross-sectional study was carried out on all users who filled in the Allergy Diary from 1 January 2016 to 1 August 2017. Secondary adherence was assessed by using the modified Medication Possession Ratio (MPR) and the Proportion of days covered (PDC) approach. Results: A total of 12143 users were registered. A total of 6949 users reported at least one VAS data recording. Among them, 1887 users reported >= 7 VAS data. About 1195 subjects were included in the analysis of adherence. One hundred and thirty-six (11.28%) users were adherent (MPR >= 70% and PDC = 70% and PDC = 1.50) and 176 (14.60%) were switchers. On the other hand, 832 (69.05%) users were non-adherent to medications (MPR Conclusion and clinical relevance: Adherence to treatment is low. The relative efficacy of continuous vs on-demand treatment for allergic rhinitis symptoms is still a matter of debate. This study shows an approach for measuring retrospective adherence based on a mobile app. This also represents a novel approach for analysing medication-taking behaviour in a real-world setting.Peer reviewe
Allergic Rhinitis and its Impact on Asthma (ARIA) Phase 4 (2018) : Change management in allergic rhinitis and asthma multimorbidity using mobile technology
Allergic Rhinitis and its Impact on Asthma (ARIA) has evolved from a guideline by using the best approach to integrated care pathways using mobile technology in patients with allergic rhinitis (AR) and asthma multimorbidity. The proposed next phase of ARIA is change management, with the aim of providing an active and healthy life to patients with rhinitis and to those with asthma multimorbidity across the lifecycle irrespective of their sex or socioeconomic status to reduce health and social inequities incurred by the disease. ARIA has followed the 8-step model of Kotter to assess and implement the effect of rhinitis on asthma multimorbidity and to propose multimorbid guidelines. A second change management strategy is proposed by ARIA Phase 4 to increase self-medication and shared decision making in rhinitis and asthma multimorbidity. An innovation of ARIA has been the development and validation of information technology evidence-based tools (Mobile Airways Sentinel Network [MASK]) that can inform patient decisions on the basis of a self-care plan proposed by the health care professional.Peer reviewe
Genotype and phenotype landscape of MEN2 in 554 medullary thyroid cancer patients: the BrasMEN study
Multiple endocrine neoplasia type 2 (MEN2) is an autosomal dominant genetic disease caused by RET gene germline mutations that is characterized by medullary thyroid carcinoma (MTC) associated with other endocrine tumors. Several reports have demonstrated that the RET mutation profile may vary according to the geographical area. In this study, we collected clinical and molecular data from 554 patients with surgically confirmed MTC from 176 families with MEN2 in 18 different Brazilian centers to compare the type and prevalence of RET mutations with those from other countries. The most frequent mutations, classified by the number of families affected, occur in codon 634, exon 11 (76 families), followed by codon 918, exon 16 (34 families: 26 with M918T and 8 with M918V) and codon 804, exon 14 (22 families: 15 with V804M and 7 with V804L). When compared with other major published series from Europe, there are several similarities and some differences. While the mutations in codons C618, C620, C630, E768 and S891 present a similar prevalence, some mutations have a lower prevalence in Brazil, and others are found mainly in Brazil (G533C and M918V). These results reflect the singular proportion of European, Amerindian and African ancestries in the Brazilian mosaic genome
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