7,004 research outputs found
Observation of magnetization reversal in epitaxial Gd0.67Ca0.33MnO3 thin films
High quality epitaxial thin films of Gd0.67Ca0.33MnO3 have been deposited
onto (100) SrTiO3 substrates by pulsed-laser deposition. Enhanced properties in
comparison with bulk samples were observed. The magnetic transition temperature
(Tc) of the as-grown films is much higher than the corresponding bulk values.
Most interestingly, magnetization measurements performed under small applied
fields, exhibit magnetization reversals below Tc, no matter whether the film is
field-cooled (FC) or zero-field-cooled (ZFC). A rapid magnetization reversal
occurs at 7 K when field cooled, while as for the ZFC process the magnetization
decreases gradually with increasing temperatures, taking negative values above
7 K and changing to positive values again, above 83 K. In higher magnetic
fields the magnetization does not change sign. The reversal mechanism is
discussed in terms of a negative exchange f-d interaction and magnetic
anisotropy, this later enhanced by strain effects induced by the lattice
mismatch between the film and the substrate.Comment: 16 pages, 4 figure
Anorectal malformations
Anorectal malformations comprise a wide spectrum of diseases, which can affect boys and girls, and involve the distal anus and rectum as well as the urinary and genital tracts. They occur in approximately 1 in 5000 live births. Defects range from the very minor and easily treated with an excellent functional prognosis, to those that are complex, difficult to manage, are often associated with other anomalies, and have a poor functional prognosis. The surgical approach to repairing these defects changed dramatically in 1980 with the introduction of the posterior sagittal approach, which allowed surgeons to view the anatomy of these defects clearly, to repair them under direct vision, and to learn about the complex anatomic arrangement of the junction of rectum and genitourinary tract. Better imaging techniques, and a better knowledge of the anatomy and physiology of the pelvic structures at birth have refined diagnosis and initial management, and the analysis of large series of patients allows better prediction of associated anomalies and functional prognosis. The main concerns for the surgeon in correcting these anomalies are bowel control, urinary control, and sexual function. With early diagnosis, management of associated anomalies and efficient meticulous surgical repair, patients have the best chance for a good functional outcome. Fecal and urinary incontinence can occur even with an excellent anatomic repair, due mainly to associated problems such as a poorly developed sacrum, deficient nerve supply, and spinal cord anomalies. For these patients, an effective bowel management program, including enema and dietary restrictions has been devised to improve their quality of life
Instructional methods in emergency online teaching: The case of a Latin American business school
Instructional methods have an impact on the learning process and the quality of educational services aimed at accomplishing learning objectives. The purpose of this paper is to examine the most preferred instructional methods during emergency online teaching used by instructors. The data was collected through semi-structured interviews with 36 full-time and part-time faculty members belonging to an accredited Hispanic business school. The results showed that faculty used many different instructional methods during synchronous and asynchronous sessions. Similarly, there is a relationship between the professors’ academic areas and the instructional methods used. Based on these results, this study proposes a reference model of instructional methods for higher education based on professors’ experiences during emergency online teaching that includes five categories: group methods, active methods to contribute to the development of competencies, methods to ascertain prior knowledge, methods that promote understanding through the organization of information and methods that use digital tools. The originality of the study lies in the fact that it analyzes the migration experience from in-person to online teaching at an accredited Hispanic business institution
Functional characterization of 8-oxoguanine DNA glycosylase of Trypanosoma cruzi
The oxidative lesion 8-oxoguanine (8-oxoG) is removed during base excision repair by the 8-oxoguanine DNA glycosylase 1 (Ogg1). This lesion can erroneously pair with adenine, and the excision of this damaged base by Ogg1 enables the insertion of a guanine and prevents DNA mutation. In this report, we identified and characterized Ogg1 from the protozoan parasite Trypanosoma cruzi (TcOgg1), the causative agent of Chagas disease. Like most living organisms, T. cruzi is susceptible to oxidative stress, hence DNA repair is essential for its survival and improvement of infection. We verified that the TcOGG1 gene encodes an 8-oxoG DNA glycosylase by complementing an Ogg1-defective Saccharomyces cerevisiae strain. Heterologous expression of TcOGG1 reestablished the mutation frequency of the yeast mutant ogg1-/- (CD138) to wild type levels. We also demonstrate that the overexpression of TcOGG1 increases T. cruzi sensitivity to hydrogen peroxide (H2O2). Analysis of DNA lesions using quantitative PCR suggests that the increased susceptibility to H2O2 of TcOGG1-overexpressor could be a consequence of uncoupled BER in abasic sites and/or strand breaks generated after TcOgg1 removes 8-oxoG, which are not rapidly repaired by the subsequent BER enzymes. This hypothesis is supported by the observation that TcOGG1-overexpressors have reduced levels of 8-oxoG both in the nucleus and in the parasite mitochondrion. The localization of TcOgg1 was examined in parasite transfected with a TcOgg1-GFP fusion, which confirmed that this enzyme is in both organelles. Taken together, our data indicate that T. cruzi has a functional Ogg1 ortholog that participates in nuclear and mitochondrial BER. © 2012 Furtado et al
On Conditional Decomposability
The requirement of a language to be conditionally decomposable is imposed on
a specification language in the coordination supervisory control framework of
discrete-event systems. In this paper, we present a polynomial-time algorithm
for the verification whether a language is conditionally decomposable with
respect to given alphabets. Moreover, we also present a polynomial-time
algorithm to extend the common alphabet so that the language becomes
conditionally decomposable. A relationship of conditional decomposability to
nonblockingness of modular discrete-event systems is also discussed in this
paper in the general settings. It is shown that conditional decomposability is
a weaker condition than nonblockingness.Comment: A few minor correction
Miositis eosinofílica en el perro : caso clínico
Se presentó en la consulta de la Facultad un perro Pastor Alemán, con una sintomatologia de intensa atrofia muscular que afectaba a los músculos maseteros y temporales, e imposibilidad de apertura de boca. Se realizó un protocolo habitual de diagnóstico, completando la historia clínica. examen delpaciente y la analítica histopatológica y hematológica. Los resultados obtenidos contrastados con la bibliografía disponible, nos hizo llegar finalmente al diagnóstico de Miositis Canina.A German sheperd dog arrived to the Veterinary Hospital of our University with an intensive muscular atrophy of the masticatory muscles. As it is usual, the protocol of diagnostic was made; the anamnesis, clinical history, and animal examination was reviewied, to follow with the haemathologic and histopathologic studies. Finally we obtained a diagnostic of Canine Miositis
Brownian Entanglement
We show that for two classical brownian particles there exists an analog of
continuous-variable quantum entanglement: The common probability distribution
of the two coordinates and the corresponding coarse-grained velocities cannot
be prepared via mixing of any factorized distributions referring to the two
particles in separate. This is possible for particles which interacted in the
past, but do not interact in the present. Three factors are crucial for the
effect: 1) separation of time-scales of coordinate and momentum which motivates
the definition of coarse-grained velocities; 2) the resulting uncertainty
relations between the coordinate of the brownian particle and the change of its
coarse-grained velocity; 3) the fact that the coarse-grained velocity, though
pertaining to a single brownian particle, is defined on a common context of two
particles. The brownian entanglement is a consequence of a coarse-grained
description and disappears for a finer resolution of the brownian motion. We
discuss possibilities of its experimental realizations in examples of
macroscopic brownian motion.Comment: 18 pages, no figure
Mapas de distribución de algas marinas de la península Ibérica y las islas Baleares. XXVIII. Dasya (Ceramiales, Rhodophyta)
[spa] Se presentan los mapas de distribución en la Península Ibérica y las islas Baleares de las especies del género Dasya, correspondientes a D. baillouviana, D. corymbifera, D. hutchinsiae, D. ocellata, D. rigescens, D. rigidula y D. sessilis. [eng] The distribution maps of the species of Dasya found along the coasts of the Iberian Peninsula and the Balearic Islands, D. baillouviana, D. corymbifera, D. hutchinsiae, D. ocellata, D. rigescens, D. rigidulaand D. sessilis, are shown
Repurposing Disulfiram as an Antimicrobial Agent in Topical Infections
Antimicrobial drugs applied topically offer several advantages. However, the widespread use of antibiotics has led to increasing antimicrobial resistance. One interesting approach in the drug discovery process is drug repurposing. Disulfiram, which was originally approved as an anti-alcoholism drug, offers an attractive alternative to treat topical multidrug resistance bacteria in skin human infections. This study aimed to evaluate the biopharmaceutical characteristics of the drug and the effects arising from its topical application in detail. Microdilution susceptibility testing showed antibacterial activity against Gram-positive bacteria Staphylococcus aureus and Streptococcus pyogenes. Dermal absorption revealed no permeation in pig skin. The quantification of the drug retained in pig skin demonstrated concentrations in the stratum corneum and epidermis, enough to treat skin infections. Moreover, in vitro cytotoxicity and micro-array analyses were performed to better understand the mechanism of action and revealed the importance of the drug as a metal ion chelator. Together, our findings suggest that disulfiram has the potential to be repurposed as an effective antibiotic to treat superficial human skin infections
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