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Lattice defects may work as a kind of apparatus for catching topological excitations, preventing their escape. So, the problem of removing skyrmions from eventual local defects in magnetic materials must be closely related to new technologies such as skyrmionic. Here, we examine the conditions for drawing a skyrmion from a magnetic impurity in a two-dimensional antiferromagnetic system by applying spin-polarized currents (SPC). Two types of impurities are investigated (local easy-axis and easy-plane anisotropy defects). Also, two methods to release the skyrmion with SPC are explored. In principle, our results could be qualitatively relevant to any other type of lattice defect.
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Magnetic skyrmions are quasiparticle-like textures that are topologically different from a single domain magnetization state. Their topological protection, combined with the low current density needed to move them, make these objects relevant to be used as information storage structures. In such a context, the analysis of the interactions between skyrmions is interesting and relevant for future applications. In this work, through micromagnetic simulations and numerical calculations, we studied the interaction between two skyrmions living on different parallel ferromagnetic racetracks connected by an exchange-like interaction. The upper and lower racetracks are separated by a height offset and the interaction between the upper and the lower skyrmion is analyzed in terms of the magnetic and geometrical parameters. Three states are predicted, as a function of these parameters: scattered or free skyrmions, bound skymions, and annihilated skyrmions. Our results, presented in a phase diagram, demonstrate that even in the case here called free skyrmions, there is a small and brief interaction when both are close enough, but the skyrmion in the top layer does not drag the skyrmion in the bottom layer. For bound skyrmions, both keep linked during larger times. In the latter case, there are strong changes in the velocity of the skyrmions induced by the effect of a higher effective mass when both are coupled.
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In this paper we investigate a magnetic racetrack consisting of a junction of three materials with different properties. Indeed, this magnetic system is composed by two distinct regions (racetracks) connected by a thin interface: the first region (termed sector 1) has isotropic in-plane magnetic chirality and supports skyrmion (S) excitations while the second (sector 3) has anisotropic chirality and consequently supports antiskyrmions (A). The interface, which would be a third region (sector 2, connecting sectors 1 and 3) located in the central part of the racetrack, is an easy-axis Heisenberg ferromagnetic material. The topological structures S and A are put in motion by applying a spin-polarized current. Under certain conditions, we show that the skyrmion and the antiskyrmion created in their respective sectors are simultaneously impelled to the interface (due to the Magnus force) to apparently become a unique object (a skyrmion-antiskyrmion pair or SAP). After glued by sector 2, the skyrmion and the antiskyrmion move together (as a SAP) along the direction of the applied current. It is also shown that such an engineered racetrack can support a sequence of several SAP structures in motion, forming a current.
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In this paper we perform nanofabrication of square artificial spin ices with different lattice parameters, in order to investigate the roles of vertex excitation on the features of the system. In particular, the character of magnetic charge distribution asymmetry on the vertices are observed under magnetic hysteresis loop experiments. We then compare our results with simulation using an emergent Hamiltonian containing objects such as magnetic monopoles and dipoles in the vertices of the array (instead of the usual Hamiltonian based on the dipolar interactions among the magnetic nanoislands). All possible interactions between these objects are considered (monopole-monopole, monopole-dipole and dipole-dipole). Using realistic parameters we observe very good match between experiments and theory, which allow us to better understand the system dynamics in function of monopole charge intensity.
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Topological objects interacting with lattice defects is an important topic in condensed matter physics. In this paper, we would like to explore the ballistic trajectory of an antiferromagnetic skyrmion in a racetrack to study processes such as collisions of skyrmions and holes in the magnetic sample. The skyrmion is impelled against the hole-obstacle by means of a spin polarized current. Depending on the skyrmion velocity (associated to the strength of the applied current) and the type of collision (frontal or lateral), it will be captured, scattered or completely destroyed by the hole. In some cases, this obstacle can shift the skyrmion center from a straight line to another one, and it appears as an effective way of manipulating skyrmion trajectories and dynamics.
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In this work, we explore a kind of geometrical effect in the thermodynamics of artificial spin ices (ASI). In general, such artificial materials are athermal. Here, We demonstrate that geometrically driven dynamics in ASI can open up the panorama of exploring distinct ground states and thermally magnetic monopole excitations. It is shown that a particular ASI lattice will provide a richer thermodynamics with nanomagnet spins experiencing less restriction to flip precisely in a kind of rhombic lattice. This can be observed by analysis of only three types of rectangular artificial spin ices (RASI). Denoting the horizontal and vertical lattice spacings by [Formula: see text] and [Formula: see text], respectively, then, a RASI material can be described by its aspect ratio [Formula: see text]. The rhombic lattice emerges when [Formula: see text]. So, by comparing the impact of thermal effects on the spin flips in these three appropriate different RASI arrays, it is possible to find a system very close to the ice regime.
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BACKGROUND: Renal transplant recipients (RTR), which are an increasing population, frequently suffer from post-transplant dermatological complications. Despite the well-established role of dermatologists in the outpatient care of these patients, no previous studies were found concerning dermatology consultations for hospitalized RTR. OBJECTIVES: To investigate the epidemiology of dermatological conditions presented by RTR during hospitalization and assess the impact of dermatology consultations performed in the hospital setting. METHODS: Dermatology consultations requested for RTR admitted at a kidney transplantation referral hospital in Brazil over 36 consecutive months were retrospectively included. RESULTS: 176 consultations were included. Infectious dermatoses prevailed (52.3%), followed by inflammatory diseases (14.2%), neoplasms (12.5%) and drug reactions (8.5%). Diagnostic agreement between requesting and consulting teams was 38.1%. Most consultations were motivated by common dermatological conditions, unrelated to admission diagnosis. There were some differences in comparison to previous studies including general inpatients, such as: larger proportion of infectious dermatoses and neoplasms, smaller proportion of inflammatory diseases, higher percentage of patients submitted to skin biopsy, smaller proportion of consultations managed with a single visit and higher probability of a systemic treatment being recommended in this population. CONCLUSION: Hospitalized RTR present distinct dermatological epidemiology and higher level of complexity, when compared to studies including general inpatients. Dermatology interventions during hospitalization may be beneficial in the multidisciplinary care of these patients, either contributing to the investigation of systemic conditions or providing relief for cutaneous comorbidities.
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Pacientes Internos/estadística & datos numéricos , Trasplante de Riñón , Complicaciones Posoperatorias/epidemiología , Derivación y Consulta , Enfermedades de la Piel/epidemiología , Adulto , Anciano , Brasil/epidemiología , Erupciones por Medicamentos/epidemiología , Femenino , Hospitales Universitarios , Humanos , Masculino , Persona de Mediana Edad , Complicaciones Posoperatorias/etiología , Derivación y Consulta/estadística & datos numéricos , Estudios Retrospectivos , Enfermedades de la Piel/etiología , Enfermedades Cutáneas Infecciosas/epidemiología , Neoplasias Cutáneas/epidemiologíaRESUMEN
In this work, we have constructed and experimentally investigated frustrated arrays of dipoles forming two-dimensional artificial spin ices with different lattice parameters (rectangular arrays with horizontal and vertical lattice spacings denoted by a and b respectively). Arrays with three different aspect ratios γ = a/b = [Formula: see text], [Formula: see text] and [Formula: see text] are studied. Theoretical calculations of low-energy demagnetized configurations for these same parameters are also presented. Experimental data for demagnetized samples confirm most of the theoretical results. However, the highest energy topology (doubly-charged monopoles) does not emerge in our theoretical model, while they are seen in experiments for large enough γ. Our results also insinuate that the string tension connecting two magnetic monopoles in a pair vanishes in rectangular lattices with a critical ratio γ = γ c = [Formula: see text], supporting previous theoretical predictions.
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In this paper we investigate the influences of the second neighbor interactions on a skyrmion lattice in two-dimensional chiral magnets. Such a system contains the exchange and the Dzyaloshinskii-Moriya for the spin interactions and therefore, we analyse three situations: firstly, the second neighbor interaction is present only in the exchange coupling; secondly, it is present only in the Dzyaloshinskii-Moriya coupling. Finally, the second neighbor interactions are present in both exchange and Dzyaloshinskii-Moriya couplings. We show that such effects cause important modifications to the helical and skyrmion phases when an external magnetic field is applied.
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Introduction The process of returning to work, especially for individuals with labor restrictions, impacts work teams and interferes with the labor reinsertion process. In this study, we aimed to understand the impact of these situations on a nursing team from both organizational and relational perspectives. Methods We conducted a qualitative research study at a university hospital in the municipality of São Paulo using three strategies: documentary analysis; semi-structured interviews with pairs of workers returning to a labor situation; and a focus group with nursing managers. Results Medical leaves of absence overburden the employees who remain working. Regarding the return to work, the participants reported both positive and negative aspects. One positive aspect reported was that those who return to work contribute to the division of labor, generating solidarity and cooperation. The negative aspects reported were related to the return of workers with labor restrictions who do not fully resume their activities, consequently generating conflicts within the work teams that interfere with the reintegration processes. The supervisors reported difficulties reorganizing work on a broad scale and assessing the workers' diagnoses and symptoms and the workers themselves in terms of the necessity of their leaves and the validity of their labor restrictions. Conclusion The organization of labor and social relationships among peers and supervisors is a significant contributor to the success or failure of the work reintegration process and therefore should be considered. We aimed to address this issue by highlighting the complexity of the return-to-work process among health workers.
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Hospitales de Enseñanza/organización & administración , Personal de Enfermería en Hospital/organización & administración , Reinserción al Trabajo/psicología , Ausencia por Enfermedad , Lugar de Trabajo/organización & administración , Brasil , Humanos , Enfermeras y Enfermeros/psicología , Lugar de Trabajo/psicologíaRESUMEN
In this work, we report experimental and theoretical investigations performed in anti-spin ice structures, composed by square lattice of elongated antidots, patterned in nickel thin film. The magnetic vortex crystal state was obtained by micromagnetic simulation as the ground state magnetization, which arises due to the magnetic stray field at the antidot edges inducing chirality in the magnetization of platters among antidots. Ferromagnetic resonance (FMR) and magnetoresistance (MR) measurements were utilized to investigate the vortex crystal magnetization dynamics and magnetoelectric response. By using FMR, it was possible to detect the spin wave modes and vortex crystal resonance, in good agreement with dynamic micromagnetic simulation results. The vortex crystal magnetization configuration and its response to the external magnetic field, were used to explain the isotropic MR behaviour observed.
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Magnetricity, the magnetic equivalent of electricity, was recently verified experimentally for the first time. Indeed, like the stream of electric charges that produces electric current, emergent magnetic monopoles have been observed to roam freely in geometrically frustrated magnets known as spin ice. However, such phenomena demand extreme physical conditions, say, a single spin ice crystal has to be cooled to very low temperature, around 0.36 K. Candidates to overcome this difficulty are their artificial analogues, the so-called artificial spin ices. Here, we demonstrate that a specific unidirectional arrangement of nanoislands yields a peculiar system where magnetic monopoles emerge and are constrained to move along aligned dipoles, providing an ordered flow of magnetic charges at room temperature.
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BACKGROUND/AIMS: Preeclampsia (PE) is a cause of glomerulopathy worldwide. Urinary retinol-binding protein (RBP) is a marker of proximal tubular dysfunction, albuminuria is an endothelial injury marker, urine protein:creatinine ratio (PCR) may have a predictive value for renal disease later in life, and, recently, podocyturia has been proposed as a sensitive tool in pregnancy, but it needs to be tested. The aim of this study was to evaluate renal involvement in PE and healthy pregnancy. METHODS: Case-control study with 39 pregnant women assessed after 20 weeks of gestation (25 in the control group, CG, and 14 in the PE group) by performing urinary tests. RESULTS: Mean (±SD) age and gestational age of the CG were 26.9 ± 6.4 years and 37.1 ± 5.0 weeks, and of the PE group 26.4 ± 6.9 years and 30.6 ± 5.6 weeks, respectively (p = 0.001). Mean (±SD) urinary RBP (p = 0.017), albuminuria (p = 0.002), and urinary albumin concentration (UAC) ratio (p = 0.006) of the CG were 0.4 ± 0.7 mg/l, 7.3 ± 6.9 mg/l, and 8.2 ± 6.7 mg/g and of the PE group 2.0 ± 4.4 mg/l, 2,267.4 ± 2,130.8 mg/l (p = 0.002), and 3,778.9 ± 4,296.6 mg/g (p = 0.006), respectively. Mean (±SD) urine PCR in the PE group was 6.7 ± 6.1 g/g (p < 0.001). No statistical differences were found between podocyturia in the CG and PE group (p = 0.258). CONCLUSIONS: Urinary RBP, PCR, albuminuria, and UAC ratio were elevated in the PE group in comparison to the CG. Podocyturia did not predict PE.
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INTRODUCTION: Preeclampsia (PE) is an important cause of glomerulopathy. Assessment of renal markers during pregnancy may have a predictive value for glomerular disease later in life. The early detection of PE may prevent the complications of this syndrome. OBJECTIVES: Assess the glomerular involvement in PE and in normal pregnancy by evaluating renal markers such as podocyturia and proteinuria. METHODS: Case-control study with 39 pregnant women after 20 weeks of gestation (control group - CG with n=25 and PE with n=14), we assessed podocyturia (cytospin method) and proteinuria (albuminuria, urine protein:creatinine - PCR, urinary retinol protein - RBP and albumin/creatinine ratio - ACR). (Grant FAPESP 08/56338-1) RESULTS: Mean±standard deviation of age and mean gestational age of CG were 26.9±6.4years and 37.1±5.0weeks and of PE, 26.4±6.9 and 30.6±5.6, respectively (p=0.001). No statistical differences were found between podocyturia in CG and PE although it was more frequent in this last group (p=0.258). Podocyte cells and parietal epithelial cells were detected in the slides. Mean±standard deviation of urinary RBP (p=0.017), albuminuria (p=0.002) and UAC ratio (p=0.006) of CG were 0.4±0.7mg/L, 7.3±6.9mg/L and 8.2±6.7mg/g and of PE, 2.0±4.4mg/L, 2267.4±2130.8mg/L (p=0.002) and 3778.9±4296.6mg/g (p=0.006), respectively. Mean value±standard deviation of urine PCR in PE was 6.7±6.1g/g (p=< 0.001). CONCLUSION: Urinary RBP, PCR, albuminuria and UAC ratio were elevated in PE in comparison to CG indicating its glomerular involvement but there was no correlation between those renal parameters and podocyturia. RPC and UAC ratios were good predictors of PE, but not podocyturia. Either podocyte cells as parietal epithelial cells were detected in the urine, these findings may indicate a non-invasive marker for renal disease activity but more studies are required to determine its role in PE.
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INTRODUCTION: Progressive proteinuria and glomerulosclerosis characterize chronic allograft nephropathy. However, the causes are not fully elucidated. Injury of parietal epithelial cells in glomeruli, the podocytes, is the initiating cause of many renal diseases, leading to proteinuria with possible progression to glomerulosclerosis. Podocytes are highly specialized cells, with an important role in maintaining the glomerular filtration barrier and producing growth factor for mesangial cells and endothelial cells. With their foot processes they cover the glomerular basement membrane, and form slit diaphragms with neighboring podocytes. The potential role of podocytes in the failing transplanted kidney is unknown. OBJECTIVES: To evaluate podocyturia as a functional marker in pregnant women with kidney grafts. METHODS: Twenty pregnant women with kidney grafts had their urine samples cytocentrifugated and evaluated by indirect immunofluorescence. The slide was incubated for 45' at room temperature with fluorescein (FITC) anti-rabbit IgG secondary antibody (Sigma-Aldrich, EUA). Then Vectashield (mounting medium for fluorescence) with DAPI (4'6-diamino-2-fenilindol dihidrocloreto) were applied H-1200 (Vector laboratories, inc, USA). The podocytes and the total number of cells were counted in 15 fields photographed under 400x magnification with a digital camera coupled to an epifluorescence microscope DM1000 (Leica, Germany) connected to a computer. The results were expressed as podocyte/total cells (%) per area of higher cell concentration (hot spots) in the field of 400x detected by staining of nuclei and cytoplasm. (Grant FAPESP 08/56338-1). RESULTS: The mean age of the women was 26years. The urinalysis was performed at the third trimester of gestation; 11 did not exhibit urinary podocytes and 9 had podocyturia. There was also a relationship between blood pressure levels, proteinuria and the excretion of podocytes. CONCLUSION: Urinary podocyte number, blood pressure and proteinuria were associated. We observed that urinary podocyte excretion occurs in pregnant women with kidney transplant almost synchronously with higher systolic and diastolic blood pressure and higher mean levels of proteinuria. The detection of podocyturia in these women could be useful for early diagnosis and follow-up of glomerular injury, eventually preeclampsia. It may be also associated to its severity or activity, although additional studies are necessary to confirm these aspects.
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PURPOSE: To establish a correlation between pH vaginal and the microflora associated in carriers of vulvovaginites. METHODS: In the present study, the cytopathological examination and the vaginal flow in a group of 65 sexually active women had been carried through, 20 and 72 years, taken care of in the Laboratório de Citologia Clínica do Departamento de Análises Clínicas e Toxicológicas da Universidade Federal do Rio Grande do Norte, for determination of microorganisms in cervicovaginal sample and of pH in the vaginal flow. RESULTS: Associating pH vaginal with the presence of vulvovaginitis, it was evidenced that the Candida sp. occurred more frequently in pH 4.0, Trichomonas vaginalis in pH 6.0, Gardnerella vaginalis in pH 5.0, coconuts in pH 5.0, bacilli in pH 4.0 and cocos/bacilos in pH 6.0. It was observed that all the patients had presented at least one type of ethiological agent of vulvovaginiti and an associated microflora. CONCLUSION: The joint accomplishment of the cytological examinations and the determination of pH revealed important for directing the microflora associated with the vulvovaginiti, suggesting, of this form, that pH vaginal plays preponderant role how much to the presence of the infectious agents in the vaginal ecosystem.
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Adulto , Anciano , Animales , Femenino , Humanos , Persona de Mediana Edad , Frotis Vaginal , Vulvovaginitis , Vagina/microbiología , Candida/aislamiento & purificación , Candidiasis Vulvovaginal/complicaciones , Gardnerella vaginalis/aislamiento & purificación , Concentración de Iones de Hidrógeno , Trichomonas vaginalis/aislamiento & purificación , Vagina/química , Vaginitis por Trichomonas/complicaciones , Vaginosis Bacteriana/complicaciones , Vulvovaginitis/metabolismo , Vulvovaginitis/microbiologíaRESUMEN
The objective of this work was to compare the values of milk somatic cell counts (SCC) using the Somacount 300, and two detergents for sample preparation. the equipment was calibrated using the detergent RBS 35. Forty independent milk samples were analyzed. Each sample was randomly divided into two subsamples, and each subsample was analyzed after preparation with either RBS 35 or Extram MA 01 Alkaline detergents. the correlation coefficient between the two methods was high (0.998). This finding suggests the possibility of substitution of RBS 35 for an economical alternative
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Recuento de Células , LecheRESUMEN
The objective of this work was to compare the values of milk somatic cell counts (SCC) using the Somacount 300, and two detergents for sample preparation. The equipment was calibrated using the detergent RBS 35. Forty independent milk samples were analyzed. Each sample was randomly divided into two subsamples, and each subsample was analyzed after preparation with either RBS 35 or Extram MA 01 Alkaline detergents. The correlation coefficient between the two methods was high (0.998). This finding suggests the possibility of substitution of RBS 35 for an economical alternative.