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1.
J Neurosci Methods ; 398: 109958, 2023 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-37661056

RESUMO

BACKGROUND: Characterization of normal arousal states has been achieved by fitting predictions of corticothalamic neural field theory (NFT) to electroencephalographic (EEG) spectra to yield relevant physiological parameters. NEW METHOD: A prior fitting method is extended to distinguish conscious and unconscious states in healthy and brain injured subjects by identifying additional parameters and clusters in parameter space. RESULTS: Fits of NFT predictions to EEG spectra are used to estimate neurophysiological parameters in healthy and brain injured subjects. Spectra are used from healthy subjects in wake and sleep and from patients with unresponsive wakefulness syndrome, in a minimally conscious state (MCS), and emerged from MCS. Subjects cluster into three groups in parameter space: conscious healthy (wake and REM), sleep, and brain injured. These are distinguished by the difference X-Y between corticocortical (X) and corticothalamic (Y) feedbacks, and by mean neural response rates α and ß to incoming spikes. X-Y tracks consciousness in healthy individuals, with smaller values in wake/REM than sleep, but cannot distinguish between brain injuries. Parameters α and ß differentiate deep sleep from wake/REM and brain injury. COMPARISON WITH EXISTING METHODS: Other methods typically rely on laborious clinical assessment, manual EEG scoring, or evaluation of measures like Φ from integrated information theory, for which no efficient method exists. In contrast, the present method can be automated on a personal computer. CONCLUSION: The method provides a means to quantify consciousness and arousal in healthy and brain injured subjects, but does not distinguish subtypes of brain injury.


Assuntos
Lesões Encefálicas , Estado de Consciência , Humanos , Estado de Consciência/fisiologia , Nível de Alerta/fisiologia , Encéfalo/fisiologia , Vigília/fisiologia , Eletroencefalografia/métodos
2.
Sci Adv ; 8(47): eadc9430, 2022 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-36417531

RESUMO

During the Cryogenian (720 to 635 Ma ago) Snowball Earth glaciations, ice extended to sea level near the equator. The cause of this catastrophic failure of Earth's thermostat has been unclear, but previous geochronology has suggested a rough coincidence of glacial onset with one of the largest magmatic episodes in the geological record, the Franklin large igneous province. U-Pb geochronology on zircon and baddeleyite from sills associated with the paleo-equatorial Franklin large igneous province in Arctic Canada record rapid emplacement between 719.86 ± 0.21 and 718.61 ± 0.30 Ma ago, 0.9 to 1.6 Ma before the onset of widespread glaciation. Geologic observations and (U-Th)/He dates on Franklin sills are compatible with major post-Franklin exhumation, possibly due to development of mafic volcanic highlands on windward equatorial Laurentia and increased global weatherability. After a transient magmatic CO2 flux, long-term carbon sequestration associated with increased weatherability could have nudged Earth over the threshold for runaway ice-albedo feedback.

3.
Nat Commun ; 13(1): 6140, 2022 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-36253357

RESUMO

In antiferromagnets, the efficient transport of spin-waves has until now only been observed in the insulating antiferromagnet hematite, where circularly (or a superposition of pairs of linearly) polarized spin-waves diffuse over long distances. Here, we report long-distance spin-transport in the antiferromagnetic orthoferrite YFeO3, where a different transport mechanism is enabled by the combined presence of the Dzyaloshinskii-Moriya interaction and externally applied fields. The magnon decay length is shown to exceed hundreds of nanometers, in line with resonance measurements that highlight the low magnetic damping. We observe a strong anisotropy in the magnon decay lengths that we can attribute to the role of the magnon group velocity in the transport of spin-waves in antiferromagnets. This unique mode of transport identified in YFeO3 opens up the possibility of a large and technologically relevant class of materials, i.e., canted antiferromagnets, for long-distance spin transport.

4.
Braz J Med Biol Res ; 55: e11735, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35170683

RESUMO

Oral tolerance blocks the development of specific immune responses to proteins ingested by the oral route. One of the first registries of oral tolerance showed that guinea pigs fed corn became refractory to hypersensitivity to corn proteins. Mice fed with chow containing corn are tolerant to zein, and parenteral injection of zein plus adjuvant blocks immunization to unrelated proteins injected concomitantly and reduces unspecific inflammation. Extensive and prolonged inflammatory infiltrate in the wound bed is one of the causes of pathological wound healing. Previous research shows that intraperitoneal injection of zein concomitant with skin injuries reduces the inflammatory infiltrate in the wound bed and improves wound healing. Herein, we tested if one subcutaneous injection of zein before skin injury improves wound healing. We also investigated how long the effects triggered by zein could improve skin wound healing. Mice fed zein received two excisional wounds on the interscapular skin under anesthesia. Zein plus Al(OH)3 was injected at the tail base at 10 min, or 3, 5, or 7 days before skin injuries. Wound healing was analyzed at days 7 and 40 after injury. Our results showed that a zein injection up to 5 days before skin injury reduced the inflammatory infiltrate, increased the number of T-cells in the wound bed, and improved the pattern of collagen deposition in the neodermis. These findings could promote the development of new strategies for the treatment and prevention of pathological healing using proteins normally found in the common diet.


Assuntos
Pele , Cicatrização , Animais , Colágeno , Cobaias , Injeções Intraperitoneais , Injeções Subcutâneas , Camundongos
5.
Braz. j. med. biol. res ; 55: e11735, 2022. graf
Artigo em Inglês | LILACS-Express | LILACS | ID: biblio-1355914

RESUMO

Oral tolerance blocks the development of specific immune responses to proteins ingested by the oral route. One of the first registries of oral tolerance showed that guinea pigs fed corn became refractory to hypersensitivity to corn proteins. Mice fed with chow containing corn are tolerant to zein, and parenteral injection of zein plus adjuvant blocks immunization to unrelated proteins injected concomitantly and reduces unspecific inflammation. Extensive and prolonged inflammatory infiltrate in the wound bed is one of the causes of pathological wound healing. Previous research shows that intraperitoneal injection of zein concomitant with skin injuries reduces the inflammatory infiltrate in the wound bed and improves wound healing. Herein, we tested if one subcutaneous injection of zein before skin injury improves wound healing. We also investigated how long the effects triggered by zein could improve skin wound healing. Mice fed zein received two excisional wounds on the interscapular skin under anesthesia. Zein plus Al(OH)3 was injected at the tail base at 10 min, or 3, 5, or 7 days before skin injuries. Wound healing was analyzed at days 7 and 40 after injury. Our results showed that a zein injection up to 5 days before skin injury reduced the inflammatory infiltrate, increased the number of T-cells in the wound bed, and improved the pattern of collagen deposition in the neodermis. These findings could promote the development of new strategies for the treatment and prevention of pathological healing using proteins normally found in the common diet.

6.
Naunyn Schmiedebergs Arch Pharmacol ; 394(5): 853-862, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33159803

RESUMO

The role of protease-activated receptor (PAR)4 in thrombin-induced platelet aggregation has been studied, and PAR4 blockade is thought to be useful as a new and promising approach in antiplatelet therapy in humans. In recent years, studies have been conducted to clarify the role of PAR4 in the host defense against invading microorganisms and pathogen-induced inflammation; however, to date, the role of PAR4 in mediating the LPS-induced inflammatory repertoire in macrophages remains to be elucidated. Here, we investigated the effects of the synthetic PAR4 agonist peptide (PAR4-AP) AYPGKF-NH2 on the phagocytosis of zymosan-FITC particles; NO, ROS, and iNOS expression; and cytokine production in C57/BL6 macrophages cocultured with PAR4-AP/LPS. The PAR4-AP impaired LPS-induced and basal phagocytosis, which was restored by pharmacological PAR4 blockade. Coincubation with the PAR4-AP/LPS enhanced NO and ROS production and iNOS expression; decreased IL-10, but not TNF-α, in the culture supernatant; and increased translocation of the p65 subunit of the proinflammatory gene transcription factor NF-κ-B. Our results provide evidence for a complex mechanism and new approach by which PAR4 mediates the macrophage response triggered by LPS through counter-regulating the phagocytic activity of macrophages and innate response mechanisms implicated in the killing of invading pathogens.


Assuntos
Inflamação/patologia , Macrófagos/efeitos dos fármacos , Oligopeptídeos/farmacologia , Receptores de Trombina/metabolismo , Animais , Feminino , Fluoresceína-5-Isotiocianato/química , Lipopolissacarídeos , Macrófagos/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Óxido Nítrico/metabolismo , Fagocitose/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Zimosan/metabolismo
7.
Nat Commun ; 11(1): 6332, 2020 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-33303758

RESUMO

Antiferromagnetic materials can host spin-waves with polarizations ranging from circular to linear depending on their magnetic anisotropies. Until now, only easy-axis anisotropy antiferromagnets with circularly polarized spin-waves were reported to carry spin-information over long distances of micrometers. In this article, we report long-distance spin-transport in the easy-plane canted antiferromagnetic phase of hematite and at room temperature, where the linearly polarized magnons are not intuitively expected to carry spin. We demonstrate that the spin-transport signal decreases continuously through the easy-axis to easy-plane Morin transition, and persists in the easy-plane phase through current induced pairs of linearly polarized magnons with dephasing lengths in the micrometer range. We explain the long transport distance as a result of the low magnetic damping, which we measure to be ≤ 10-5 as in the best ferromagnets. All of this together demonstrates that long-distance transport can be achieved across a range of anisotropies and temperatures, up to room temperature, highlighting the promising potential of this insulating antiferromagnet for magnon-based devices.

8.
Fish Shellfish Immunol ; 101: 234-243, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32240748

RESUMO

Establishing new animal models for the study of inflammation is very important in the process of discovering new drugs, since the inflammatory event is the basis of many pathological processes. Whereas rodent models have been the primary focus of inflammation research, we defend the zebrafish (Danio rerio) test as a feasible alternative for preclinical studies. Moreover, despite all the technological development already achieved by humanity, nature can still be considered a relevant source of new medicines. In this context, the aim of this work was to evaluate the anti-inflammatory effect of a substance isolated from the medicinal plant Annona crassilfora Mart, the peltatoside, in an inflammatory model of zebrafish. It was determined: (i) total leukocyte count in the coelomate exudate; (ii) N-acetyl-ß-d-glucuronidase (NAG); (iii) myeloperoxidase (MPO); (iv) and the histology of liver, intestine and mesentery. Peltotoside (25, 50 and 100 µg) and dexamethasone (25 µg) were administered intracelomatically (i.c.) 30 min before carrageenan (i.c.). Pretreatment with peltatoside at three doses significantly inhibited leukocyte recruitment in the coelomic cavity, and inhibited NAG and MPO activity against the action of Cg, in a similar manner as dexamethasone. However, some microlesions in the evaluated organs were detected. The dose of 25 µg showed an anti-inflammatory effect with lower undesirable effects in the tissues. Our results suggest that the zebrafish test was satisfactory in performing our analyzes and that the peltotoside has a modulatory action in reducing leukocyte migration.


Assuntos
Annona/química , Anti-Inflamatórios/farmacologia , Modelos Animais de Doenças , Glicosídeos/farmacologia , Inflamação/tratamento farmacológico , Extratos Vegetais/farmacologia , Quercetina/análogos & derivados , Peixe-Zebra , Animais , Anti-Inflamatórios/administração & dosagem , Anti-Inflamatórios/química , Glicosídeos/administração & dosagem , Glicosídeos/química , Extratos Vegetais/administração & dosagem , Extratos Vegetais/química , Folhas de Planta/química , Plantas Medicinais/química , Quercetina/administração & dosagem , Quercetina/química , Quercetina/farmacologia
9.
ACS Appl Mater Interfaces ; 12(5): 6752-6760, 2020 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-31927947

RESUMO

The magnetoelectric properties of exchange-coupled Ni/CoFeB-based composite multiferroic microstructures are investigated. The strength and sign of the magnetoelastic effect are found to be strongly correlated with the ratio between the thicknesses of two magnetostrictive materials. In cases where the thickness ratio deviates significantly from one, the magnetoelastic behavior of the multiferroic microstructures is dominated by the thicker layer, which contributes more strongly to the observed magnetoelastic effect. More symmetric structures with a thickness ratio equal to one show an emergent interfacial behavior which cannot be accounted for simply by summing up the magnetoelastic effects occurring in the two constituent layers. This aspect is clearly visible in the case of ultrathin bilayers, where the exchange coupling drastically affects the magnetic behavior of the Ni layer, making the Ni/CoFeB bilayer a promising next-generation synthetic magnetic system entirely. This study demonstrates the richness and high tunability of composite multiferroic systems based on coupled magnetic bilayers compared to their single magnetic layer counterparts. Furthermore, because of the compatibility of CoFeB with present magnetic tunnel junction-based spintronic technologies, the reported findings are expected to be of great interest for the development of ultralow-power magnetoelectric memory devices.

10.
Rev Med Interne ; 41(1): 3-7, 2020 Jan.
Artigo em Francês | MEDLINE | ID: mdl-31722837

RESUMO

INTRODUCTION: Immune thrombocytopenia (ITP) is an acquired hemorrhagic disease due to antiplatelet antibodies, that will become a chronic disease in 70% of adults. Most of chronic ITP patients display clonal restriction of antiplatelet antibodies. To date, there is no biomarker able to predict the evolution of the disease. The objective of the study is to determine whether Hevylite® and/or Freelite® assays are prognostic factors for progression to chronic ITP. METHODS: This is a retrospective, monocentric, prognostic study of a biomarker, performed using frozen samples stored in a serum library. Freelite® and a Hevylite® assays were performed on the samples collected at diagnosis for adult patients with newly diagnosed ITP at the University Hospital of Poitiers between 2014/01/01 and 2017/05/01. To predict the evolution into a chronic disease, a ROC curve analysis was performed on four variables: IgGκ, IgGκ/IgGλ ratio, IgGκ - IgGλ, and κ/λ ratio. RESULTS: Thirty-two patients were included and analyzed. No patient had an abnormal κ/λ ratio. Three patients had an abnormal IgGκ/IgGλ ratio. The following variables IgGκ, IgGκ/IgGλ, IgGκ - IgGλ, and κ/λ ratio were not able to predict progression to chronic ITP in our study. CONCLUSION: This study did not reveal any prognostic value of the Freelite® and Hevylite® tests on the evolution of ITP into a chronic disease.


Assuntos
Imunoensaio , Imunoglobulina G/sangue , Cadeias Pesadas de Imunoglobulinas/sangue , Cadeias Leves de Imunoglobulina/sangue , Púrpura Trombocitopênica Idiopática/sangue , Biomarcadores/sangue , Progressão da Doença , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Retrospectivos
12.
Scand J Med Sci Sports ; 26(9): 1109-16, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26369504

RESUMO

The pelvic floor (PF) provides support to all pelvic organs, as well as appropriately closure/opening mechanism of the urethra, vagina, and anus. Therefore, it is likely that female athletes involved in high-impact and in strong-effort activities are at risk for the occurrence of urinary incontinence (UI). This study aimed to investigate the occurrence of UI and other PF dysfunctions (PFD) [anal incontinence (AI), symptoms of constipation, dyspareunia, vaginal laxity, and pelvic organ prolapse] in 67 amateur athletes (AT) compared with a group 96 of nonathletes (NAT). An ad hoc survey based on questions from reliable and valid instruments was developed to investigate the occurrence of PFD symptoms. The risk of UI was higher in AT group (odds ratio: 2.90; 95% CI: 1.50-5.61), mostly among artistic gymnastics and trampoline, followed by swimming and judo athletes. Whereas, AT group reported less straining to evacuate (OR: 0.46; 95% CI: 0.22-0.96), manual assistance to defecate (OR: 0.24; 95% CI: 0.05-1.12), and a higher stool frequency (OR: 0.29; 95% CI: 0.13-0.64) than NAT group. The occurrence of loss of gas and sexual symptoms was high for both groups when compared with literature, although with no statistical difference between them. Pelvic organ prolapse was only reported by nonathletes. Athletes are at higher risk to develop UI, loss of gas, and sexual dysfunctions, either practicing high-impact or strong-effort activities. Thus, pelvic floor must be considered as an entity and addressed as well. Also, women involved in long-term high-impact and strengthening sports should be advised of the impact of such activities on pelvic floor function and offered preventive PFD strategies as well.


Assuntos
Constipação Intestinal/epidemiologia , Dispareunia/epidemiologia , Incontinência Fecal/epidemiologia , Prolapso de Órgão Pélvico/epidemiologia , Esportes/estatística & dados numéricos , Incontinência Urinária/epidemiologia , Adolescente , Adulto , Brasil/epidemiologia , Estudos Transversais , Feminino , Ginástica/estatística & dados numéricos , Inquéritos Epidemiológicos , Humanos , Artes Marciais/estatística & dados numéricos , Natação/estatística & dados numéricos , Voleibol/estatística & dados numéricos , Adulto Jovem
13.
Gac. méd. boliv ; 36(1): 6-10, jun. 2013. ilus
Artigo em Espanhol | LILACS | ID: lil-737888

RESUMO

Objetivos: el objetivo de la investigación fue aislar protozoarios kinetoplástidos a partir de mamíferos silvestres en tres departamentos de Bolivia, con la finalidad de identificar reservorios de tripanosomátidos que podrían causar infección en diferentes reservorios y enfermedades en el humano. Métodos: Los mamíferos silvestres fueron capturados en el Chaco, valles interandinos y la zona tropical de Bolivia, utilizando trampas Sherman, Havahard y Tomahawk. Los animales capturados fueron anestesiados para realizar el xenodiagnóstico y la extracción de sangre por punción cardiaca; el aislamiento de tripanosomátidos se realizó por hemocultivo utilizando medios de cultivo NNN y su respectiva identificación por las técnicas de PCR-RFLP en el laboratorio de Biología molecular IIBISMED. Resultados: fueron capturados 236 mamíferos silvestres pertenecientes a 30 especies, de las cuales 7 especies presentaron infección por hemoflagelados. Trypanosoma cruzi fue aislado de Didelphis marsupialis, D. albiventris, Galea musteloides, Graomys domorum y Andalgalomis pearsoni; T.c marinkellei y T. dionisii fueron aislados de Carolia perspicillata (murciélagos) y otros kinetoplástidos no identificados por herramientas moleculares disponibles fueron aislados de mamíferos del género Graomys y Andalgalomys, capturados en las provincias Campero de Cochabamba y Cordillera del departamento de Santa Cruz. Conclusiones: El T. cruzi, T.c. marinkellei, T. dionisii y otros tripanosomátidos se encuentran infectando a marsupiales (Didelphis), roedores (Graomys y Andalgalomys) y cobayos silvestres (Galea) los cuales se encuentran en su ciclo silvestre en las zonas estudiadas.


Objectives: The aim of this research was isolate kinetoplastid protozoan from wild mammals in three departments of Bolivia, to identify Trypanosomatids reservoirs that could cause infection in different reservoirs and disease in humans. Methods: The wild mammals were caught in the Chaco, valleys and the tropical zone of Bolivia, using Sherman, Havahard and Tomahawk traps. Captured animals were anesthetized and xenodiagnosis and blood cardiac puncture was performed; trypanosomatides isolation using blood culture was done in NNN culture media and the respective identification was performed by PCR-RFLP techniques in the molecular biology laboratory of IIBISMED. Results: 236 wild mammals belonging to 30 species were captured, of which 7 species showed infection by hemoflagellates. Trypanosoma cruzi was isolated from Didelphis marsupialis, D. albiventris, Galea musteloides, Graomys domorum and Andalgalomis pearsoni; T.c. marinkellei and T. dionisii were isolated from Carolia perspicillata (bats) and other kinetoplastid not identified by available molecular tools were also isolated from Andalgalomys and Graomys mammals genus, from Campero and Cordillera provinces of Cochabamba and Santa Cruz. Conclusions: The T. cruzi, T.c. marinkellei, T. dionisii and other trypanosomatids are infecting marsupials (Didelphis), rodents (Graomys and Andalgalomys) and wild guinea pigs (Galea) which are found in a sylvatic cycle in the studied areas.


Assuntos
Tripanossomíase
14.
Vet Immunol Immunopathol ; 149(3-4): 272-9, 2012 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-22939274

RESUMO

The pig is a relevant preclinical model for numerous pathologies used to validate therapeutic strategies for translation to human. Although invariant natural killer T (iNKT) lymphocytes are a component of innate immunity implicated in many pathological processes, little is known on their characterization in swine. By addressing this issue using mouse α-galactosylceramide-loaded CD1d tetramers (α-GC-CD1dTT), which are commonly used to track iNKT cells, we were able to unequivocally identify CD3(+)α-GC-CD1dTT(+) cells in porcine peripheral blood, hereafter referred to as swine iNKT cells. These lymphocytes are enriched in CD4(-)CD8(+) and CD4(-)CD8(-) cells, harbor an activated-memory phenotype (SLA-DR(+)CD45RA(-)), express the intracellular promyelocytic-leukemia-zinc-finger (PLZF) transcription factor and are significantly enriched in IFN-γ-producing cells after in vitro activation in comparison with conventional T cells. Importantly, in presence of IL-2 and IL-15, the iNKT cell ligand α-GC induces selective expansion of CD3(+)α-GC-CD1dTT(+) cells, confirming the reactivity of swine iNKT cells against α-GC. When associated with α-GC, IL-33, an alarmin of IL-1 family recently described to target iNKT cells, leads to a greater expansion of CD3(+)α-GC-CD1dTT(+) cells than IL-2 and IL-15. Altogether, our results provide the first phenotypic and functional description of swine iNKT cells allowing to further study the critical role of iNKT cells in porcine models of organ injury.


Assuntos
Antígenos CD1d/imunologia , Galactosilceramidas/imunologia , Imunidade Inata/imunologia , Células T Matadoras Naturais/imunologia , Suínos/imunologia , Animais , Citocinas/sangue , Citocinas/imunologia , Citometria de Fluxo/veterinária , Imunofenotipagem/métodos , Imunofenotipagem/veterinária , Leucócitos Mononucleares/citologia , Leucócitos Mononucleares/imunologia , Masculino , Células T Matadoras Naturais/citologia , Estatísticas não Paramétricas , Suínos/sangue
15.
Phys Rev Lett ; 108(1): 017602, 2012 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-22304291

RESUMO

Graphite, a model (semi)metal with trigonally warped bands, is investigated with a magnetoabsorption experiment and viewed as an electronic system in the vicinity of the Lifshitz transition. A characteristic pattern of up to 20 cyclotron resonance harmonics has been observed. This large number of resonances, their relative strengths and characteristic shapes trace the universal properties of the electronic states near a separatrix in momentum space. Quantum-mechanical perturbative methods with respect to the trigonal warping term hardly describe the data which are, on the other hand, fairly well reproduced within a quasiclassical approach and conventional band structure model. Trigonal symmetry is preserved in graphite in contrast to a similar system, bilayer graphene.

16.
Rev Med Chil ; 138(4): 444-51, 2010 Apr.
Artigo em Espanhol | MEDLINE | ID: mdl-20668792

RESUMO

BACKGROUND: The effects of aging on people must be evaluated to adequate sanitary actions. AIM: To assess the characteristics of older subjects living in Antofagasta, Chile. MATERIAL AND METHODS: Cross sectional assessment of 602 subjects without dementia, aged more than 60 years (55% females). A socioeconomic and medical history was obtained and Barthel, Lawton, Yesavage depression, Tromp fall risk and Folstein Mini mental scales were applied. RESULTS: Sixty eight percent of subjects had more than six years of studies. Forty six percent had hypertension, 28% had osteoarticular problems, 20% had hypercholesterolemia and 17% diabetes mellitus. Four percent had depression and falls were reported by 35%. Seventy four percent were independent in basic and instrumental activities. Ninety four percent had normal cognitive functions. Age was an important determinant of functional capacity. CONCLUSIONS: The main problems detected in this sample were the risk of falls and the presence of chronic diseases.


Assuntos
Acidentes por Quedas/estatística & dados numéricos , Envelhecimento/fisiologia , Avaliação Geriátrica/estatística & dados numéricos , Atividades Cotidianas , Distribuição por Idade , Idoso , Idoso de 80 Anos ou mais , Análise de Variância , Chile/epidemiologia , Estudos Transversais , Escolaridade , Feminino , Nível de Saúde , Humanos , Masculino , Pessoa de Meia-Idade , Medição de Risco , Estatísticas não Paramétricas
17.
Rev. méd. Chile ; 138(4): 444-451, abr. 2010. tab
Artigo em Espanhol | LILACS | ID: lil-553215

RESUMO

Background: The effects of aging on people must be evaluated to adequate sanitary actions. Aim: To assess the characteristics of older subjects living in Antofagasta, Chile. Material and Methods: Cross sectional assessment of 602 subjects without dementia, aged more than 60 years (55 percent females). A socioeconomic and medical history was obtained and Barthel, Lawton, Yesavage depression, Tromp fall risk and Folstein Mini mental scales were applied. Results: Sixty eight percent of subjects had more than six years of studies. Forty six percent had hypertension, 28 percent had osteoarticular problems, 20 percent had hypercholesterolemia and 17 percent diabetes mellitus. Four percent had depression and falls were reported by 35 percent. Seventy four percent were independent in basic and instrumental activities. Ninety four percent had normal cognitive functions. Age was an important determinant of functional capacity. Conclusions: The main problems detected in this sample were the risk of falls and the presence of chronic diseases.


Assuntos
Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Acidentes por Quedas/estatística & dados numéricos , Envelhecimento/fisiologia , Avaliação Geriátrica/estatística & dados numéricos , Atividades Cotidianas , Distribuição por Idade , Análise de Variância , Chile/epidemiologia , Estudos Transversais , Escolaridade , Nível de Saúde , Medição de Risco , Estatísticas não Paramétricas
18.
Inorg Chem ; 49(4): 1932-41, 2010 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-20078096

RESUMO

High-frequency electron paramagnetic resonance (HF-EPR) spectroscopy was employed to examine the oxidation state and local structure of Ni and Mn ions in Ni,Mn-codoped LiCoO(2). The assignment of EPR signals was based on Mg,Mn-codoped LiCoO(2) and Ni-doped LiCoO(2) used as Mn(4+) and low-spin Ni(3+) EPR references. Complementary information on the oxidation state of transition-metal ions was obtained by solid-state (6,7)Li NMR spectroscopy. For slightly doped oxides (LiCo(1-x)Ni(x)Mn(x)O(2) with x < 0.05), nickel and manganese substitute for cobalt in the CoO(2) layers and are stabilized as Ni(3+) and Mn(4+) ions. The local structure of Mn(4+) ions was determined by modeling of the axial zero-field-splitting parameter in the framework of the Newman superposition model. It has been found that the local trigonal distortion around Mn(4+) is smaller in comparison with that of the host site. To achieve a local compensation of Mn(4+) charge, several defect models are discussed. With an increase in the total dopant content (LiCo(1-x)Ni(x)Mn(x)O(2) and 0.05

19.
Phys Rev Lett ; 103(13): 136403, 2009 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-19905531

RESUMO

We have identified the cyclotron resonance response of the purest graphene ever investigated, which can be found in nature on the surface of bulk graphite, in the form of decoupled layers from the substrate material. Probing such flakes with Landau level spectroscopy in the THz range at very low magnetic fields, we demonstrate a superior electronic quality of these ultralow density layers (n_{0} approximately 3 x 10;{9} cm;{-2}) expressed by the carrier mobility in excess of 10;{7} cm;{2}/(V * s) or scattering time of tau approximately 20 ps. These parameters set new and surprisingly high limits for intrinsic properties of graphene and represent an important challenge for further developments of current graphene technologies.

20.
Phys Chem Chem Phys ; 11(31): 6555-68, 2009 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-19639130

RESUMO

The current status and future developments of the use of electron magnetic resonance (EMR) for the investigation of magnetic nano-systems is here reviewed. The aim is to stimulate efforts to provide a unified view of the properties of magnetic nanoparticles (MNP) comprising a few hundred magnetic centres, and molecular nanomagnets which contain up to ca. one hundred magnetic centres (MNM). The size of the systems is becoming the same but the approaches to the interpretation of their properties are still different, being bottom up for the latter and top down for the former. We make the point here of the need for a common viewpoint, highlighting the status of the two fields and giving some hints for the future developments. EMR has been a powerful tool for the investigation of magnetic nano-objects and it can provide a tool of fundamental importance for the development of a unified view.

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