Toward Fully Multiferroic van der Waals SpinFETs: Basic Design and Quantum Calculations.

Manipulating spin transport enhances the functionality of electronic devices, allowing them to surpass physical constraints related to speed and power. For this reason, the use of van der Waals multiferroics at the interface of heterostructures offers promising prospects for developing high-performance devices, enabling the electrical control of spin information. Our work focuses primarily on a mechanism for multiferroicity in two-dimensional van der Waals materials that stems from an interplay between antiferromagnetism and the breaking of inversion symmetry in certain bilayers. We provide evidence for spin-electrical couplings that include manipulating van der Waals multiferroic edges via external voltages and the subsequent control of spin transport including for fully multiferroic spin field-effect transistors.

Model for Nonrelativistic Topological Multiferroic Matter.

We provide a model capable of accounting for the multiferroicity in certain materials. The model's base is on free electrons and spin moments coupled within nonrelativistic quantum mechanics. The synergistic interplay between the magnetic and electric degrees of freedom that turns into the multiferroic phenomena occurs at a profound quantum mechanical level, conjured by Berry's phases and the quantum theory of polarization. Our results highlight the geometrical nature of the multiferroic order parameter that naturally leads to magnetoelectric domain walls, with promising technological potential.

Hopfion-Driven Magnonic Hall Effect and Magnonic Focusing.

Hopfions are localized and topologically nontrivial magnetic configurations that have received considerable attention in recent years. In this Letter, we use a micromagnetic approach to analyze the scattering of spin waves (SWs) by magnetic hopfions. Our results evidence that SWs experience an electromagnetic field generated by the hopfion and sharing its topological properties. In addition, SWs propagating along the hopfion symmetry axis are deflected by the magnetic texture, which acts as a convergent or divergent lens, depending on the SWs' propagation direction. Assuming that SWs propagate along the plane perpendicular to the symmetry axis, the scattering is closely related to the Aharonov-Bohm effect, allowing us to identify the magnetic hopfion as a scattering center.

Magnetic Otto Engine for an Electron in a Quantum Dot: Classical and Quantum Approach.

We studied the performance of classical and quantum magnetic Otto cycle with a working substance composed of a single quantum dot using the Fock-Darwin model with the inclusion of the Zeeman interaction. Modulating an external/perpendicular magnetic field, in the classical approach, we found an oscillating behavior in the total work extracted that was not present in the quantum formulation.We found that, in the classical approach, the engine yielded a greater performance in terms of total work extracted and efficiency than when compared with the quantum approach. This is because, in the classical case, the working substance can be in thermal equilibrium at each point of the cycle, which maximizes the energy extracted in the adiabatic strokes.

Whole genome sequencing of the monomorphic pathogen Mycobacterium bovis reveals local differentiation of cattle clinical isolates.

BACKGROUND: Bovine tuberculosis (bTB) poses serious risks to animal welfare and economy, as well as to public health as a zoonosis. Its etiological agent, Mycobacterium bovis, belongs to the Mycobacterium tuberculosis complex (MTBC), a group of genetically monomorphic organisms featured by a remarkably high overall nucleotide identity (99.9%). Indeed, this characteristic is of major concern for correct typing and determination of strain-specific traits based on sequence diversity. Due to its historical economic dependence on cattle production, Uruguay is deeply affected by the prevailing incidence of Mycobacterium bovis. With the world's highest number of cattle per human, and its intensive cattle production, Uruguay represents a particularly suited setting to evaluate genomic variability among isolates, and the diversity traits associated to this pathogen. RESULTS: We compared 186 genomes from MTBC strains isolated worldwide, and found a highly structured population in M. bovis. The analysis of 23 new M. bovis genomes, belonging to strains isolated in Uruguay evidenced three groups present in the country. Despite presenting an expected highly conserved genomic structure and sequence, these strains segregate into a clustered manner within the worldwide phylogeny. Analysis of the non-pe/ppe differential areas against a reference genome defined four main sources of variability, namely: regions of difference (RD), variable genes, duplications and novel genes. RDs and variant analysis segregated the strains into clusters that are concordant with their spoligotype identities. Due to its high homoplasy rate, spoligotyping failed to reflect the true genomic diversity among worldwide representative strains, however, it remains a good indicator for closely related populations. CONCLUSIONS: This study introduces a comprehensive population structure analysis of worldwide M. bovis isolates. The incorporation and analysis of 23 novel Uruguayan M. bovis genomes, sheds light onto the genomic diversity of this pathogen, evidencing the existence of greater genetic variability among strains than previously contemplated.

Magnonic Black Holes.

We show that the interaction between the spin-polarized current and the magnetization dynamics can be used to implement black-hole and white-hole horizons for magnons-the quanta of oscillations in the magnetization direction in magnets. We consider three different systems: easy-plane ferromagnetic metals, isotropic antiferromagnetic metals, and easy-plane magnetic insulators. Based on available experimental data, we estimate that the Hawking temperature can be as large as 1 K. We comment on the implications of magnonic horizons for spin-wave scattering and transport experiments, and for magnon entanglement.

Magnetostatic interaction between Bloch point nanospheres.

Three-dimensional topological textures have become a topic of intense interest in recent years. This work uses analytical and numerical calculations to determine the magnetostatic field produced by a Bloch point (BP) singularity confined in a magnetic nanosphere. It is observed that BPs hosted in a nanosphere generate magnetic fields with quadrupolar nature. This finding is interesting because it shows the possibility of obtaining quadrupole magnetic fields with just one magnetic particle, unlike other propositions considering arrays of magnetic elements to generate this kind of field. The obtained magnetostatic field allows us to determine the interaction between two BPs as a function of the relative orientation of their polarities and the distance between them. It is shown that depending on the rotation of one BP related to the other, the magnetostatic interaction varies in strength and character, being attractive or repulsive. The obtained results reveal that the BP interaction has a complex behavior beyond topological charge-mediated interaction.

Quality of life in the older adults: The protective role of self-efficacy in adequate coping in patients with chronic diseases.

The purpose of the present study was to establish the association between self-efficacy, perception of disease, emotional regulation, and fatigue and the health-related quality of life in older adults living in the departments of Cesar and Atlántico in Colombia and who have been diagnosed with a chronic disease. The participants were 325 older adults of both sexes, with literacy and no presence of cognitive impairment in the Mini-Mental State Examination (MMSE); A non-probabilistic sampling was carried out. We used the MOS-SF-36 questionnaire, the Brief Illness Perception Questionnaire scale for measuring the perception of disease, the Stanford Patient Education Research Center's Chronic Disease Self self-efficacy questionnaire for chronic patients, the Difficulties in Emotional Regulation Scale, and the Fatigue Severity Questionnaire as measurement instruments. The design was non-experimental cross-sectional with a correlational scope. The results indicate that self-efficacy, disease perception, emotional regulation and severity of fatigue are variables that could impact the physical function of quality of life, confirming that self-efficacy would work as a factor that decreases the probability that a participant score low on this dimension of quality of life. On the other hand, both the perception of the disease and the severity of fatigue were identified as factors that probably negatively influence quality of life.

Psychometric properties of the self-efficacy scale for chronic disease management (SEMCD-S) in older Colombian adults.

BACKGROUND: Self-efficacy alludes to personal competence in an individual's effectiveness when facing stressful situations. This construct has been related to different domains of the health field, finding that high levels of self-efficacy benefit human functioning and enhance well-being. METHODS: The present study aimed to determine the psychometric properties of the self-efficacy scale for managing chronic diseases (SEMCD-S) by assessing factorial, convergent and divergent validity, reliability, and measurement invariance. Likewise, the comparison of self-efficacy according to socio-demographic characteristics was proposed by contrasting latent factors. An instrumental, transactional, descriptive, and non-experimental design study was carried out with the participation of 325 Colombian senior citizens. RESULTS: The findings suggest that the scale has appropriate psychometric properties. The one-factor structure exhibited a satisfactory fit, the mean-variance extracted reported acceptable figures and the correlation analysis with other constructs supported this instrument's convergent and discriminant validity. Likewise, it was invariant to the different socio-demographic aspects examined, while the internal consistency figures were high. Differences in the means of the latent factors were only detected in the academic grade. In this case, older adults with a primary school level attained higher self-efficacy values than those who had completed high school or university studies. CONCLUSIONS: It is concluded that the self-efficacy scale for chronic disease management is a valid and reliable instrument that can be used in the Colombian context to measure and compare this construct.

Insights into the mechanism of an S(N)2 reaction from the reaction force and the reaction electronic flux.

The mechanism of a simple S(N)2 reaction, viz; OH(-) + CH(3)F = CH(3)OH + F(-) has been studied within the framework of reaction force and reaction electronic flux. We have computationally investigated three different types of reaction mechanisms with two different types of transition states, leading to two different products. The electronic transfer contribution of the reaction electronic flux was found to play a crucial role in this reaction. Natural bond order analysis and dual descriptor provide additional support for elucidating the mechanism of this reaction.

Machine-learning-accelerated multimodal characterization and multiobjective design optimization of natural porous materials.

Natural porous materials such as nanoporous clays are used as green and low-cost adsorbents and catalysts. The key factors determining their performance in these applications are the pore morphology and surface activity, which are typically represented by properties such as specific surface area, pore volume, micropore content and pH. The latter may be modified and tuned to specific applications through material processing and/or chemical treatment. Characterization of the material, raw or processed, is typically performed experimentally, which can become costly especially in the context of tuning of the properties towards specific application requirements and needing numerous experiments. In this work, we present an application of tree-based machine learning methods trained on experimental datasets to accelerate the characterization of natural porous materials. The resulting models allow reliable prediction of the outcomes of experimental characterization of processed materials (R 2 from 0.78 to 0.99) as well as identification of key factors contributing to those properties through feature importance analysis. Furthermore, the high throughput of the models enables exploration of processing parameter-property correlations and multiobjective optimization of prototype materials towards specific applications. We have applied these methodologies to pinpoint and rationalize optimal processing conditions for clays exploitable in acid catalysis. One of such identified materials was synthesized and tested revealing appreciable acid character improvement with respect to the pristine material. Specifically, it achieved 79% removal of chlorophyll-a in acid catalyzed degradation.

Separate MRI quantification of dispersed (ferritin-like) and aggregated (hemosiderin-like) storage iron.

A new MRI method is proposed for separately quantifying the two principal forms of tissue storage (nonheme) iron: ferritin iron, a dispersed, soluble fraction that can be rapidly mobilized, and hemosiderin iron, an aggregated, insoluble fraction that serves as a long-term reserve. The method utilizes multiple spin echo sequences, exploiting the fact that aggregated iron can induce nonmonoexponential signal decay for multiple spin echo sequences. The method is validated in vitro for agarose phantoms, simulating dispersed iron with manganese chloride, and aggregated iron with iron oxide microspheres. To demonstrate feasibility for human studies, preliminary in vivo data from two healthy controls and six patients with transfusional iron overload are presented. For both phantoms and human subjects, conventional R(2) and R(2)* relaxation rates are also measured in order to contrast the proposed method with established MRI iron quantification techniques. Quantification of dispersed (ferritin-like) iron may provide a new means of monitoring the risk of iron-induced toxicity in patients with iron overload and, together with quantification of aggregated (hemosiderin-like) iron, improve the accuracy of estimates for total storage iron.

Quantum tunneling in nanomagnetic systems with different uniaxial anisotropy order.

A study of macroscopic quantum tunneling (MQT) of the magnetic moment in systems with quadratic and higher order uniaxial anisotropy and Zeeman interaction is presented. By using the instanton technique, under the giant spin approximation, the escape rate or probability per unit of time Gamma that the system undergoes a transition between coherent or metastable states is calculated. Using an effective particle potential we also determine the escape temperature T(e)(T), which marks the transition from quantum tunneling to thermal activation. A discussion is presented about the different models and the behavior of the magnetic system under the tunneling regime.

Modeling the Accuracy of Two in-vitro Bovine Tuberculosis Tests Using a Bayesian Approach.

Accuracy of new or alternative diagnostic tests is typically estimated in relation to a well-standardized reference test referred to as a gold standard. However, for bovine tuberculosis (bTB), a chronic disease of cattle, affecting animal and public health, no reliable gold standard is available. In this context, latent-class models implemented using a Bayesian approach can help to assess the accuracy of diagnostic tests incorporating previous knowledge on test performance and disease prevalence. In Uruguay, bTB-prevalence has increased in the past decades partially because of the limited accuracy of the diagnostic strategy in place, based on intradermal testing (caudal fold test, CFT, for screening and comparative cervical test, CCT, for confirmation) and slaughter of reactors. Here, we evaluated the performance of two alternative bTB-diagnostic tools, the interferon-gamma assay, IGRA, and the enzyme-linked immunosorbent assay (ELISA), which had never been used in Uruguay in the absence of a gold standard. In order to do so animals from two heavily infected dairy herds and tested with CFT-CCT were also analyzed with the IGRA using two antigens (study 1) and the ELISA (study 2). The accuracy of the IGRA and ELISA was assessed fitting two latent-class models: a two test-one population model (LCA-a) based on the analysis of CFT/CFT-CCT test results and one in-vitro test (IGRA/ELISA), and a one test-one population model (LCA-b) using the IGRA or ELISA information in which the prevalence was modeled using information from the skin tests. Posterior estimates for model LCA-a suggested that IGRA was as sensitive (75-78%) as the CFT and more sensitive than the serial use of CFT-CCT. Its specificity (90-96%) was superior to the one for the CFT and equivalent to the use of CFT-CCT. Estimates from LCA-b models consistently yielded lower posterior Se estimates for the IGRA but similar results for its Sp. Estimates for the Se (52% 95%PPI:44.41-71.28) and the Sp (92% 95%PPI:78.63-98.76) of the ELISA were however similar regardless of the model used. These results suggest that the incorporation of IGRA for detection of bTB in highly infected herds could be a useful tool to improve the sensitivity of the bTB-control in Uruguay.

Treatment of acetabular chondral lesions with microfracture technique.

INTRODUCTION: Acetabular cartilage lesions are frequently found during hip arthroscopy. In the hip joint they mostly occur secondary to a mechanical overload resulting from a pre-existing deformity as hip dysplasia or femoroacetabular impingement (FAI). Lesions identified during arthroscopy can vary greatly from the earliest stages to the most advanced (full-thickness lesions). These lesions occur in the acetabulum in the early stages of joint damage. Microfractures are indicated in full-thickness chondral defects. Ideally, these lesions must be focal and contained. METHODS: The procedure begins debriding all the unstable chondral tissue of the lesion. The edges should have a net cut towards stable and healthy cartilage. It is recommended to make as many perforations as possible using arthroscopic awls. They should be ideally 4 mm deep and must have a vertical orientation to the surface. The suggested distance between perforations is of 3-4 mm. Once the treatment of the chondral lesion with the microfractures is complete, the labrum must be repaired. The repair of the labrum transforms in most of the cases the defect in a contained lesion containing better the clot in the lesion after the microfractures have been performed. It is also important to correct the bone deformity that has caused this lesion, which mostly corresponds to a "cam" deformity. CONCLUSION: Clinical studies confirm good short- and medium-term results in full-thickness chondral lesions treated with microfractures in the absence of osteoarthritis. However, it is difficult to determine if these results are only due to the microfractures, as this treatment is always complemented with several other factors and surgical procedures, such as labrum repair, correction of underlying bone deformity or change in postoperative activity of operated patients.

Hip arthroscopy and osteoarthritis: Where are the limits and indications?

The use of hip arthroscopy, as a surgical technique, has increased significantly over the past ten years. The procedure has shown good and excellent results in symptom relief and function improvement for patients with femoro-acetabular impingement (FAI) and concurrent chondro-labral lesions. It is also a reliable method to correct the characteristic pathomorphologic alteration of FAI. However, surgical results are less successful among patients with advanced articular damage and secondary hip osteoarthritis. The aim of this article is to present some clinical and imagenological tools to discriminate the good candidates for arthroscopic FAI treatment from those who are not, due to extensive articular damage.

The mechanism of Menshutkin reaction in gas and solvent phases from the perspective of reaction electronic flux.

The mechanism of Menshutkin reaction, NH(3) + CH(3)Cl = [CH(3)-NH(3)]+ + Cl-, has been thoroughly studied in both gas and solvent (H(2)O and cyclohexane) phase. It has been found that solvents favor the reaction, both thermodynamically and kinetically. The electronic activity that drives the mechanism of the reaction was identified, fully characterized, and associated to specific chemical events, bond forming/breaking processes, by means of the reaction electronic flux. This led to a complete picture of the reaction mechanism that was independently confirmed by natural bond-order analysis and the dual descriptor for chemical reactivity and selectivity along the reaction path.

Measurement and correction of stimulated echo contamination in T2-based iron quantification.

The purpose of this study was to characterize the effects of stimulated echo contamination on MR-based iron measurement derived from quantitative T2 images and develop a method for retrospective correction. Two multiple spin-echo (MSE) pulse sequences were implemented with different amounts of stimulated echo contamination. Agarose-based phantoms were constructed that simulate the relaxation and susceptibility properties of tissue with different concentrations of dispersed (ferritin-like) and aggregated (hemosiderin-like) iron. Additionally, myocardial iron was assessed in nine human subjects with transfusion iron overload. These data were used to determine the influence of stimulated echoes on iron measurements made by an MR-based iron quantification model that can separately measure dispersed and aggregated iron. The study found that stimulated echo contamination caused an underestimation of dispersed (ferritin-like) iron and an overestimation of aggregated (hemosiderin-like) iron when applying this model. The relationship between the measurements made with and without stimulated echo appears to be linear. The findings suggest that while it is important to use MSE sequences with minimal stimulated echo in T2-based iron quantification, it appears that data acquired with sub-optimal sequences can be retrospectively corrected using the methodology described here.

Actualización en manejo del status convulsivo en niños / Status epilepticus in childhood. An Update

El estatus epiléptico (SE) en pediatría es una emergencia neurológica ya que presenta morbimortalidad. Existen diferencias con los adultos y su reconocimiento puede ser más difícil especialmente a edades tempranas. Se han precisado distintas etapas en el SE y se ha acortado el tiempo en su definición, lo anterior con el objetivo de dar opciones terapéuticas más precoces. Existen diversos protocolos terapéuticos y en todos ellos las benzodiazepinas constituyen la primera etapa, incluyendo la terapia pre-hospitalaria que si es bien realizada puede evitar la progresión al SE en un paciente con una crisis epiléptica. En estatus refractario y super refractario la evidencia es menor y el rol de los anestésicos es protagónico con la necesidad de un manejo integral en una unidad de cuidados intensivos pediátricos (UCIP) y con un monitoreo electroencefalográfico continuo (cEEG), este último resulta ser un recurso limitado especialmente en el sistema público. Palabras Claves: estado epiléptico, monitoreo EEG continuo, pacientes pediátricos, anticonvulsivantes.

Status epilepticus (SE) in pediatric patients is a neurological emergency because it is associated to morbidity and mortality. There are differences between children and adults, making its recognition harder, especially in early ages. Different stages have been defined in SE and the time has been shortened in its definition, with the aim to give earlier therapeutic options. There are several protocols and in all of them benzodiazepines are the first option, even in the pre-hospital scenario, which, if managed well, can avoid progression to SE in a patient with an epileptic seizure. In refractory SE the evidence is poor and the role of anesthetics is more important with the need for an comprehensive management in a pediatric intensive care unit (PICU) and with continuous electroencephalographic monitoring (eEEG), the latter being a limited resource especially in our public health system. Key words: Status epilepticus, pediatric patients, continuous EEG monitoring, antiepileptic drugs.

Current-induced exchange interactions and effective temperature in localized moment systems.

We study theoretically the spin dynamics of a magnetic dimer serving as a contact between two electrodes. We find that the spin-spin coupling in the dimer can be dramatically modified from its equilibrium value. We show that the interaction can be tuned in such a way that it effectively changes its sign. The calculations show that, for large enough bias, the exchange interaction can even be changed from antiferromagnetic to ferromagnetic. The physical principles behind this result can be used as a new tool to achieve magneto-electric effects in molecular magnet systems.