Ferromagnetism and interlayer exchange coupling in short period (Ga,Mn)As/GaAs superlattices

Magnetic properties of (Ga,Mn)As/GaAs superlattices are investigated. The structures contain magnetic (Ga,Mn)As layers, separated by thin layers of non-magnetic GaAs spacer. The short period Ga$_{0.93}$Mn$_{0.07}$As/GaAs superlattices exhibit a paramagnetic-to-ferromagnetic phase transition close to 60K, for thicknesses of (Ga,Mn)As down to 23 \AA. For Ga$_{0.96}$Mn$_{0.04}$As/GaAs superlattices of similar dimensions, the Curie temperature associated with the ferromagnetic transition is found to oscillate with the thickness of non magnetic spacer. The observed oscillations are related to an interlayer exchange interaction mediated by the polarized holes of the (Ga,Mn)As layers.Comment: REVTeX 4 style; 4 pages, 2 figure

Mn induced modifications of Ga 3d photoemission from (Ga, Mn)As: evidence for long range effects

Using synchrotron based photoemission, we have investigated the Mn-induced changes in Ga 3d core level spectra from as-grown ${\rm Ga}_{1-x}{\rm Mn}_{x}{\rm As}$. Although Mn is located in Ga substitutional sites, and does therefore not have any Ga nearest neighbours, the impact of Mn on the Ga core level spectra is pronounced even at Mn concentrations in the range of 0.5%. The analysis shows that each Mn atom affects a volume corresponding to a sphere with around 1.4 nm diameter.Comment: Submitted to Physical Review B, Brief Repor

Post-growth annealing of GaMnAs under As capping - an alternative way to increase Tc

We demonstrate that in situ post-growth annealing of GaMnAs layers under As capping is adequate for achieving high Curie temperatures (Tc) in a similar way as ex situ annealing in air or in N2 atmosphere practiced earlier.Comment: 13 pages, 4 figure

Photoemission studies of Ga1−x_{1-x}Mnx_{x}As: Mn-concentration dependent properties

Using angle-resolved photoemission, we have investigated the development of the electronic structure and the Fermi level pinnning in Ga$_{1-x}$Mn$_{x}$As with Mn concentrations in the range 1--6%. We find that the Mn-induced changes in the valence-band spectra depend strongly on the Mn concentration, suggesting that the interaction between the Mn ions is more complex than assumed in earlier studies. The relative position of the Fermi level is also found to be concentration-dependent. In particular we find that for concentrations around 3.5--5% it is located very close to the valence-band maximum, which is in the range where metallic conductivity has been reported in earlier studies. For concentration outside this range, larger as well as smaller, the Fermi level is found to be pinned at about 0.15 eV higher energy.Comment: REVTeX style; 7 pages, 3 figure

Comparison of image analysis software packages in the assessment of adhesion of microorganisms to mucosal epithelium using confocal laser scanning microscopy

We have compared current image analysis software packages in order to find the most useful one for assessing microbial adhesion and inhibition of adhesion to tissue sections. We have used organisms of different sizes, the bacterium Helicobacter pylori and the yeast Candida albicans. Adhesion of FITC-labelled H. pylori and C. albicans was assessed by confocal microscopy. Four different Image analysis software packages, NIH-Image, IP Lab, Image Pro+, and Metamorph, were compared for their ability to quantify adhesion of the two organisms and several quantification methods were devised for each package. For both organisms, the dynamic range that could be detected by the software packages was 1×106?1×109 cells/ml. Of the four software packages tested, our results showed that Metamorph software, using our ?Region of Interest? method, with the software's ?Standard Area Method? of counting, was the most suitable for quantifying adhesion of both organisms because of its unique ability to separate clumps of microbial cells. Moreover, fewer steps were required. By pre-incubating H. pylori with the glycoconjugate Lewis b-HSA, an inhibition of binding of 48.8% was achieved using 250 ?g/ml Lewis b-HSA. The method we have devised using Metamorph software, provides a simple, quick and accurate way of quantifying adhesion and inhibition of adhesion of microbial cells to the epithelial surface of tissue sections. The method can be applied to organisms ranging in size from small bacteria to larger yeast cells

Proceso atención de enfermería en paciente de 26 años con abdomen agudo.

Acute abdomen is characterized by being a critical situation that causes a series of severe abdominal symptoms, some of the clinical manifestations are: acute abdominal pain, gastrointestinal alterations, repercussion on the general state, According to Martínez (2016), acute abdomen disease is closely related to related to the characteristics of abdominal pain. There are 3 types of pain that are related to the acute abdomen: visceral, somatic and referred. For adequate treatment, an immediate differential diagnosis must be established between pathologies that require medical treatment or emergency surgical resolution. The present clinical case study reflects the clinical symptoms of a 26-year-old female patient with a medical diagnosis of acute abdomen, during the physical evaluation and complementary examinations it is finished with a definitive diagnosis, appendicitis, the nursing staff applied the Care Process nursing, for the timely recovery of the patient.Acute abdomen is characterized by being a critical situation that causes a series of severe abdominal symptoms, some of the clinical manifestations are: acute abdominal pain, gastrointestinal alterations, repercussion on the general state, According to Martínez (2016), acute abdomen disease is closely related to related to the characteristics of abdominal pain. There are 3 types of pain that are related to the acute abdomen: visceral, somatic and referred. For adequate treatment, an immediate differential diagnosis must be established between pathologies that require medical treatment or emergency surgical resolution. The present clinical case study reflects the clinical symptoms of a 26-year-old female patient with a medical diagnosis of acute abdomen, during the physical evaluation and complementary examinations it is finished with a definitive diagnosis, appendicitis, the nursing staff applied the Care Process nursing, for the timely recovery of the patient.Abdomen agudo se caracteriza por ser una situación crítica que cursa una serie de síntomas abdominales graves, unas de las manifestaciones clínicas son: dolor abdominal agudo, alteraciones gastrointestinales, repercusión sobre el estado general, Según Martínez (2016), la enfermedad de abdomen agudo está estrechamente relacionado con las características de dolor abdominal. Hay 3 tipos de dolor que se relacionan con el abdomen agudo: Dolor visceral, Dolor somático y Dolor referido. Para un tratamiento adecuado se debe establecer un diagnóstico diferencial inmediato entre patologías que necesiten tratamiento médico o resolución quirúrgica de emergencia. El presente estudio de caso clínico refleja la sintomatología clínica de una paciente de sexo femenino de 26 años con diagnóstico médico de abdomen agudo, durante la valoración física y exámenes complementarios se termina con diagnóstico definitivo, apendicitis, la cual fue intervenida quirúrgicamente por apendicectomía convencional, el personal de enfermería aplicó el Proceso de atención de enfermería, para la recuperación oportuna de la paciente