Phenotypic plasticity rather than ecotypic differentiation explains the broad realized niche of a Neotropical orchid species.

Local adaptation is common in plant species, and knowing whether a population is locally adapted has fundamental and applied relevance. However, local adaptation in tropical plants remains largely less studied, and covering this gap is not simple since reciprocal transplantation - the gold standard for detecting local adaptation - is not feasible for most species. Here, we combined genetic, climatic and phenotypic data to investigate ecotypic differentiation, an important aspect of local adaptation, in coastal and inland populations of the orchid Epidendrum fulgens Brongn., a long-lived tropical plant for which reciprocal transplantation would not be feasible. We used nine microsatellite markers to estimate genetic divergence between inland and coastal populations. Moreover, occurrence data and climate data were used to test for differences in the realized niche of those populations. Finally, we assessed saturated water content, leaf specific area, height, and stomatal density in common garden and in situ to investigate the effects of ecotypic differentiation and plasticity on the phenotype. Coastal and inland groups' niches do not overlap, the former occupying a wetter and warmer area. However, this differentiation does not seem to be driven by ecotypic differentiation since there was no positive correlation between genetic structure and climate dissimilarity. Moreover, specific leaf area and leaf saturated water content, which are important phenotypic traits related to soil fertility and drought stress, were rather plastic. We conclude that ecotypic differentiation is absent, since phenotypic plasticity is an important mechanism explaining the niche broadness of this species.

The multiple actions of dipeptidyl peptidase 4 (DPP-4) and its pharmacological inhibition on bone metabolism: a review.

BACKGROUND: Dipeptidyl peptidase 4 (DPP-4) plays a crucial role in breaking down various substrates. It also has effects on the insulin signaling pathway, contributing to insulin resistance, and involvement in inflammatory processes like obesity and type 2 diabetes mellitus. Emerging effects of DPP-4 on bone metabolism include an inverse relationship between DPP-4 activity levels and bone mineral density, along with an increased risk of fractures. MAIN BODY: The influence of DPP-4 on bone metabolism occurs through two axes. The entero-endocrine-osseous axis involves gastrointestinal substrates for DPP-4, including glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptides 1 (GLP-1) and 2 (GLP-2). Studies suggest that supraphysiological doses of exogenous GLP-2 has a significant inhibitory effect on bone resorption, however the specific mechanism by which GLP-2 influences bone metabolism remains unknown. Of these, GIP stands out for its role in bone formation. Other gastrointestinal DPP-4 substrates are pancreatic peptide YY and neuropeptide Y-both bind to the same receptors and appear to increase bone resorption and decrease bone formation. Adipokines (e.g., leptin and adiponectin) are regulated by DPP-4 and may influence bone remodeling and energy metabolism in a paracrine manner. The pancreatic-endocrine-osseous axis involves a potential link between DPP-4, bone, and energy metabolism through the receptor activator of nuclear factor kappa B ligand (RANKL), which induces DPP-4 expression in osteoclasts, leading to decreased GLP-1 levels and increased blood glucose levels. Inhibitors of DPP-4 participate in the pancreatic-endocrine-osseous axis by increasing endogenous GLP-1. In addition to their glycemic effects, DPP-4 inhibitors have the potential to decrease bone resorption, increase bone formation, and reduce the incidence of osteoporosis and fractures. Still, many questions on the interactions between DPP-4 and bone remain unanswered, particularly regarding the effects of DPP-4 inhibition on the skeleton of older individuals. CONCLUSION: The elucidation of the intricate interactions and impact of DPP-4 on bone is paramount for a proper understanding of the body's mechanisms in regulating bone homeostasis and responses to internal stimuli. This understanding bears significant implications in the investigation of conditions like osteoporosis, in which disruptions to these signaling pathways occur. Further research is essential to uncover the full extent of DPP-4's effects on bone metabolism and energy regulation, paving the way for novel therapeutic interventions targeting these pathways, particularly in older individuals.

Wunderlich syndrome as a rare complication of polyarteritis nodosa: a case report.

Spontaneous subcapsular and perirenal hemorrhage, known as Wunderlich syndrome (WS), is a rare clinical manifestation of polyarteritis nodosa (PAN). We report a case of a 48-year-old male with a history of recurrent episodes of leg muscle tenderness and dysesthesia, bilateral flank pain, painful nodular skin lesions in the lower limbs, weight loss, and difficult-to-control arterial hypertension. The abdominopelvic computed tomography angiography showed a large left perirenal hematoma, leading to the patient's admission to the intensive care unit. After the exclusion of infectious or neoplastic foci, the patient was diagnosed with PAN and started intravenous methylprednisolone pulses with a good response. Since WS is a rare initial clinical manifestation of PAN, an early diagnosis and aggressive treatment will significantly improve clinical outcomes.

Uveitis in patients with oligoarticular juvenile idiopathic arthritis and juvenile spondyloarthritis/enthesitis related arthritis: is there any difference?

Juvenile idiopathic arthritis (JIA) is the most common systemic disease causing uveitis in childhood and adolescence.

Oxidative stress response system in Escherichia coli arising from diphenyl ditelluride (PhTe)2 exposure.

The toxicity of diphenyl ditelluride (PhTe)2 is associated with its ability to oxidize sulfhydryl groups from biological molecules. Therefore, we evaluated possible molecular mechanisms of toxicity induced by this organochalcogen in Escherichia coli (E. coli) by evaluating oxidative damage markers, relative expression of genes associated with the cellular redox state in bacteria, such as katG, sodA, sodB, soxS, and oxyR, as well as the activity of enzymes responsible for cellular redox balance. After exposure of (PhTe)2 (6, 12, and 24 µg/mL), there was a decrease in non-protein thiols (NPSH) levels, an increase in protein carbonylation and lipid peroxidation in E. coli. Intra- and extracellular reactive species (RS) was increased at concentrations of 6, 12, and 24 µg/mL. The superoxide dismutase (SOD) activity was increased at the three concentrations tested, while catalase (CAT) activity was higher at 12 and 24 µg/mL. The soxS gene showed lower expression at the three concentrations tested, while the oxyR gene was supressed at 24 µg/mL. The katG antioxidant response gene showed lower expression, and sodA and sodB were positively activated, except for sodB at 6 µg/mL. Our findings demonstrate that exposure to (PhTe)2 induced RS formation, NPSH depletion and changes in transcriptional factors regulation, characterizing it as a multi-target compound, causing disruption in cellular oxidative state, as well as molecular mechanisms associated in E. coli.

Spontaneous emission in inertial and dissipative nematic liquid crystals: the role of critical phenomena.

We develop a rigorous, field-theoretical approach to the study of spontaneous emission in inertial and dissipative nematic liquid crystals (LCs), disclosing an alternative application of the massive Stückelberg gauge theory to describe critical phenomena in these systems. This approach allows one not only to unveil the role of phase transitions in the spontaneous emission in LCs but also to make quantitative predictions for quantum emission in realistic nematics of current scientific and technological interest in the field of metamaterials. Specifically, we predict that one can switch on and off quantum emission in LCs by varying the temperature in the vicinities of the crystalline-to-nematic phase transition, for both the inertial and dissipative cases. We also predict from first principles the value of the critical exponent that characterizes such a transition, which we show not only to be independent of the inertial or dissipative dynamics, but also to be in good agreement with experiments. We determine the orientation of the dipole moment of the emitter relative to the nematic director that inhibits spontaneous emission, paving the way to achieve directionality of the emitted radiation, a result that could be applied in tuneable photonic devices such as metasurfaces and tuneable light sources.

Morbidity and mortality in Holstein calves from birth to 145 days of age on a large dairy farm in Brazil / Morbidade e mortalidade em bezerras da raça Holandesa do nascimento aos 145 dias de vida, em uma grande fazenda produtora de leite no Brasil

The present study aimed to investigate the morbidity and mortality associated with the most common diseases during the rearing period of Holstein calves in a high-production dairy farm. The calves (n = 600) were allocated to three groups based on age: G1 (1-7 days, n = 216), G2 (30-40 days, n = 188), and G3 (69-85 days, n = 196). They were evaluated over 60 days at eight different times. The morbidity rates were 47.67% (286/600) for diarrhea, 73.00% (438/600) for bovine respiratory disease (BRD), and 3.83% (23/600) for umbilical inflammation (UI). The mortality rate was 2.33% (14/600) for all the animals studied. The morbidity differed in the groups, with higher rates of diarrhea (78.85%, 166/216) and UI (6.94%, 15/216) in G1, and the highest rate of BRD in G3 (79.59%, 156/196). Diarrhea was associated with the occurrence of BRD in G1 and G2. Even in farms with good management practices, there is high morbidity associated with diarrhea and BRD, with the morbidity rate for diarrhea decreasing and that for BRD increasing as the animals get older. In addition, diarrhea is an important risk factor for BRD, especially in younger animals.(AU)

O presente estudo objetivou investigar a morbidade e a mortalidade associadas às doenças mais comuns no período de criação de bezerras da raça Holandesa, em uma fazenda leiteira de alta produção. As bezerras (n = 600) foram alocadas em três grupos de acordo com a idade: G1 (1-7 dias, n = 216); G2 (30-40 dias, n = 188); G3 (69-85 dias, n = 196). Os animais foram avaliados durante 60 dias, em oito momentos diferentes. A morbidade foi de 47,67% (286/600) para diarreia, 73,00% (438/600) para doença respiratória bovina (DRB) e 3,83% (23/600) para inflamação umbilical (IU). A taxa de mortalidade foi de 2,33% (14/600), para o total de animais avaliados. A morbidade foi diferente entre os grupos, com maior frequência de diarreia (78,85%, 166/216) e IU (6,94%, 15/216) no G1, sendo a maior ocorrência de DRB no G3 (79,59%, 156/196). A diarreia foi associada à DRB no G1 e no G2. Mesmo em fazendas com boas práticas de manejo, há alta morbidade por diarreia e DRB, com a taxa de morbidade por diarreia diminuindo e a de DRB aumentando à medida que os animais envelhecem. Além disso, a diarreia é um importante fator de risco para DRB, especialmente em animais mais jovens.(AU)

Enantioselection and chiral sorting of single microspheres using optical pulling forces.

We put forward a novel, twofold scheme that enables, at the same time, all-optical enantioselection and sorting of single multipolar chiral microspheres based on optical pulling forces exerted by two non-collinear, non-structured, circularly polarized light sources. Our chiral resolution method can be externally controlled by varying the angle between their incident wavevectors, allowing for fine-tuning of the range of chiral indices for enantioselection. Enantioselectivity is achieved by choosing angles such that only particles with the same handedness of the light sources are pulled. This proposal allows one to achieve all-optical sorting of chiral microspheres with arbitrarily small chiral parameters, thus outperforming current optical methods.

Improvement of pure sensory mononeuritis multiplex and IgG1 deficiency with sitagliptin plus Vitamin D3.

INTRODUCTION: Mononeuritis multiplex (MM) is an unusual form of peripheral neuropathy involving at least two noncontiguous peripheral nerve trunks. The pure sensory form of MM occurs rarely. Immunoglobulin (Ig)G subclass deficiency is a clinically and genetically heterogeneous disorder. Up to 50% of adults with selective subnormal IgG1 levels or selective IgG1 deficiency have a concomitant autoimmune disorder. Herein, we report the case of a patient with MM and selective IgG1 deficiency who showed remarkable clinical improvement after 2-year combination therapy with the DPP-4 inhibitor sitagliptin plus vitamin D3. CASE REPORT: A 49-year-old man developed numbness in right hand and forearm. After 6 months, the patient developed left forefoot numbness. Approximately 8 years later, the patient started to develop numbness also in the right forefoot, along with symptoms of evening fatigue and occasional orthostatic hypotension. The patient also reported recurrent candidiasis in glans and intergluteal areas since adolescence. Electromyoneurography of lower and upper limbs revealed the presence of multiple mononeuropathies. Protein electrophoresis showed hypogammaglobulinemia and low serum IgG1 levels. Sural nerve biopsy showed the presence of perineuritis. The patient was diagnosed with MM due to perineuritis probably secondary to IgG1 deficiency. We, then, proposed combination therapy with sitagliptin and vitamin D3 in the attempt to achieve immunomodulation. At the last follow-up visit (2 years), the patient showed persistent clinical improvement, increase in IgG1 levels and normalization of protein electrophoresis. CONCLUSIONS: To the best of our knowledge, this is the first case showing a remarkable clinical improvement of MM and selective IgG1 deficiency achieved through a combination therapy with sitagliptin and vitamin D3.

Synthesis of benzoylthiourea derivatives and analysis of their antibacterial performance against planktonic Staphylococcus aureus and its biofilms.

Following the appearance of several antimicrobial agents to control the spread of infections, two major challenges have emerged: (i) the occurrence and blowout of multiresistant bacteria and the increase of chronic diseases and (ii) difficult-to-eradicate infections. In this study, we tested five benzoylthiourea derivatives for their ability to inhibit and stop bacterial growth and evaluated the possible influence of 1,2,4-triazolyl-benzoylthiourea derivative 4 on the formation and eradication of Staphylococcus aureus biofilms. Benzoylthiourea derivatives 4, 6, 10, 11 and 13 were obtained in one or two steps with low cost and subjected to tests to identify their minimum inhibitory concentration (MIC) and minimum bactericidal concentration. In vitro tests were also performed to assess their effects on biofilm formation and in preformed biofilms and scanning electron microscopy was used to visualize the effects on biofilm formation. The 1,2,4-triazolyl-benzoylthiourea derivative 4 showed bacteriostatic activity against the S. aureus HU25 clinical strain with an MIC of 16 µg ml-1 , which is below the toxic concentration (at 2500 µg ml-1 , 62·25% of the cells remained viable). Compound 4 also effectively prevented biofilm formation at the three subinhibitory concentrations tested (1/2 MIC, 1/4 MIC and 1/8 MIC) as confirmed by scanning electron microscopy. For breakdown of formed biofilms, the main influence was at a subinhibitory concentration (1/2 MIC). These findings make compound 4 a strong candidate for studies on the development of new antimicrobial and antibiofilm agents.

The use of an Allonais inaequalis reproduction test as an ecotoxicological bioassay.

Ecotoxicological bioassays have been widely utilized to evaluate the toxicity of substances to organisms. However, the main challenge for researchers is finding native species to assess the effects of pollutants on aquatic biota. The tropical Oligochaeta, Allonais inaequalis, can be used as a test organism in bioassays to understand the effects of toxicants on aquatic ecosystems and their impact on native aquatic biota. In this study, we tested four methodological designs to validate the use of our "Allonais inaequalis reproduction test" as an ecotoxicological bioassay. For each sample, the assay consisted of a bottle containing 10 mg of sterilized fine sand, 60 mL of dechlorinated tap water and 6 organisms, fed at the beginning of the test and again after 5 days. The assay was first established in a controlled environment and then used to evaluate a stressed environment containing one of the following three toxicants suggested by the OECD (2008) and Corbi et al. (2015): zinc chloride, copper sulfate, or potassium chloride. Our results showed that the best experimental design for reproduction analysis was a static, long-term bioassay, which lasted 10 days without aeration and allowed for the reproduction of multiple generations (10 ± 5 new organisms). The observed inhibition reproduction by toxicants (EC50 ranging between 0.2 mg L-1 and 1.36 g L-1) validated the methods used in this paper. The use of a reproduction endpoint is a new contribution to the ecotoxicological toolbox, examining responses from a native organism to predict the effects of pollutants in an aquatic environment.

The role of hybridization and introgression in maintaining species integrity and cohesion in naturally isolated inselberg bromeliad populations.

Hybridization is a widespread phenomenon present in numerous lineages across the tree of life. Its evolutionary consequences range from effects on the origin and maintenance, to the loss of biodiversity. We studied genetic diversity and intra- and interspecific gene flow between two sympatric populations of closely-related species, Pitcairnia flammea and P. corcovadensis (Bromeliaceae), which are adapted to naturally fragmented Neotropical inselbergs, based on nuclear and plastidial DNA. Our main results indicate a strong reproductive isolation barrier, although low levels of interspecific gene flow were observed in both sympatric populations. The low rates of intraspecific gene flow observed for both P. corcovadensis and P. flammea populations corroborate the increasing body of evidence that inselberg bromeliad species are maintained as discrete evolutionary units despite the presence of low genetic connectivity. Nuclear patterns of genetic diversity and gene flow revealed that hybridization and introgression might not cause species extinction via genetic assimilation of the rare P. corcovadensis. In the face of reduced intraspecific gene exchange, hybridization and introgression may be important aspects of the Pitcairnia diversification process, with a positive evolutionary impact at the bromeliad community level, and thus contribute to increasing and maintaining genetic diversity in local isolated inselberg populations.

Modeling anisotropic magnetoresistance in layered antiferromagnets.

We have investigated the electronic transport and the anisotropic magnetoresistance in systems consisting of pairs of antiferromagnetically aligned layers separated by a non-magnetic layer, across which an antiferromagnetic coupling between the double layers is established. Calculations have been performed within the framework of the tight-binding model, taking into account the exchange coupling within the ferromagnetic layers and the Rashba spin-orbit interaction. Conductivities have been evaluated in the ballistic regime, based on Kubo formula. We have systematically studied the dependence of the conductivity and of the anisotropic magnetoresistance on several material and structural parameters, such as the orientation of the magnetic moments relative to the crystalline axis, band filling, out-of-plane hopping and spin-orbit parameter.

Consumo aparente de frutas, hortalizas y alimentos ultraprocesados en la población chilena / Apparent intake of fruit, vegetables, and ultra-processed foods by the Chilean population

Objetive: The objective of this study was to characterize the apparent intake of fruit, vegetables, and ultra-processed foods in the Chilean population according to the income quintiles. Methods: A descriptive cross-sectional study was conducted using the 7th Family Budget Survey database of the Instituto Nacional de Estadística (National Statistics Institute, INE), which includes 10,528 households from different zones of the country. Average monthly household expenses were evaluated according to income quintile for all food groups, especially fruit, vegetables, and ultra-processed foods. Results: Food intake is determined by socioeconomic level. Healthier intake patterns were observed in the higher quintiles where monthly spending was proportionately higher for fish, dairy products, cheese, eggs, fruit, and vegetables, and proportionately lower for bread and cereals, meat, oils, and fats. Conclusions: It is necessary to implement structural measures under the concept of "health in all policies", which support change in the population's dietary pattern toward natural and healthier food.

El objetivo de este estudio fue caracterizar el consumo aparente de frutas, verduras y alimentos ultraprocesados, según quintiles de ingreso en la población chilena. Metodología: Se realizó un estudio transversal descriptivo, con la base de datos de la VII Encuesta de Presupuestos Familiares realizada por el Instituto Nacional de Estadística (INE), con una muestra total de 10.528 hogares de diferentes zonas del país. Se evaluó la estructura de gasto promedio mensual efectuado por los hogares, según quintil de ingreso en todos los grupos de alimentos con especial énfasis en frutas, hortalizas y alimentos ultraprocesados. Resultados: El nivel socioeconómico determina el consumo de alimentos, observándose patrones de consumo más saludables en los quintiles superiores, con mayor proporción mensual de gasto en pescado, productos lácteos, queso, huevos, frutas y hortalizas y menor proporción de gasto en pan y cereales, carnes, aceites y grasas. Conclusión: Es necesario implementar medidas estructurales bajo el concepto de "salud en todas las políticas", que apoyen el cambio de patrón alimentario de la población hacia alimentos naturales y más saludables.

Efecto de edulcorantes no calóricos en la calidad sensorial de jugo de naranja / Effect of non caloric sweeteners in sensory quality of orange juice

The consumption of non-caloric sweeteners is increasing in Chile being present in a wide variety of foods. The objective of this study was to evaluate the effect of distinct non-caloric sweeteners in the sensory qualities of orange juice as compared to sugar. The sweeteners selected were stevia, sucralose, saccharin and aspartame. These were added to natural juices in amounts equivalent to sugar in sweetness. Sensory analysis was performed with a group of youths of both sexes. An acceptability test was applied with an hedonic scale of 5 points evaluating aroma and flavor. The results indicate that the juice aroma is not affected by the use of sugar or sweeteners rated 3.5 to 3.7 (corresponding to "I like"). However, in the evaluation of flavor, significant differences were found, the best results corresponding to juice sweetened with sugar and sucralose (3,5 y 3,6 respectively).

El consumo de edulcorantes no calóricos es cada vez más masivo en nuestro país y están presentes en una gran variedad de alimentos. El objetivo de este estudio fue evaluar el efecto de edulcorantes no calóricos en la calidad sensorial de jugo de naranja, en comparación con el azúcar. Los edulcorantes seleccionados fueron estevia, sucralosa, sacarina y aspartamo. Se adicionaron a jugos naturales en cantidades equivalentes de dulzor respecto al azúcar. El análisis sensorial se realizó con un grupo de jóvenes de ambos sexos. Se aplicó una prueba de aceptabilidad con escala hedónica de 5 puntos, evaluando los parámetros de aroma y sabor. Los resultados indican que el aroma de los jugos no se ve afectado por la utilización de azúcar o edulcorantes, con calificación entre 3,5 a 3,7 (que corresponde a "me gusta"). Sin embargo, en la evaluación de sabor las muestras significativamente mejor evaluadas corresponden a jugos endulzados con azúcar y sucralosa (3,5 y 3,6 respectivamente).

Molding the flow of light with a magnetic field: plasmonic cloaking and directional scattering.

We investigate electromagnetic (EM) scattering and plasmonic cloaking in a system composed of a dielectric cylinder coated with a magneto-optical shell. In the long-wavelength limit we demonstrate that the application of an external magnetic field can not only switch on and off the cloaking mechanism but also mitigate losses, as the absorption cross section is shown to drop sharply precisely at the cloaking operation frequency band. We also show that the angular distribution of the scattered radiation can be effectively controlled by applying an external magnetic field, allowing for a swift change in the scattering pattern. By demonstrating that these results are feasible with realistic, existing magneto-optical materials, such as graphene epitaxially grown on SiC, we suggest that magnetic fields could be used as effective, versatile external agents to tune plasmonic cloaks and to dynamically control EM scattering in an unprecedented way. We hope that these results may find use in disruptive photonic technologies.

Development and characterization of microsatellite loci for Tabebuia cassinoides (Bignoniaceae).

Tabebuia cassinoides (Lam.) DC., popularly known as caxeta, is a tree species that belongs to the plant family Bignoniaceae. This species is endemic to the Brazilian Atlantic Forest and is widely exploited commercially. To date, little is known about its genetic structure, preventing the establishment of adequate management plans for this taxon. The objective of this study was to construct a microsatellite-enriched genomic library for T. cassinoides to select polymorphic loci, and standardize polymerase chain reaction amplification conditions. Of the 15 loci examined, 5 were polymorphic. The number of alleles per locus ranged from 2 to 8, with a mean of 4.4. The microsatellite loci described here represent the basis for detailed population genetic studies of this species, which will greatly contribute for the development of better conservation strategies for this taxon.

Post-transplantation weight gain: prevalence and the impact of steroid-free therapy.

INTRODUCTION: Weight gain after renal transplantation has a multifactorial etiology, which can be associated with complications such as hypertension, dyslipidemia and diabetes, with a probable impact on cardiovascular morbidity and mortality post-transplantation. OBJECTIVE: The objectives of this study were to investigate the prevalence of weight gain and obesity post-transplantation among renal recipients of a hospital and to evaluate the impact of immunosuppressive therapy without steroids. MATERIALS AND METHODS: We have evaluated all patients who had kidney transplantations performed between January 2005 and December 2009 at General Hospital of Fortaleza, who were older than 18 years of age and had at least 12 months of follow-up post-transplantation. Overweight was defined as body mass index (BMI) between 25 and 30 kg/m(2) and obesity >30 kg/m(2). The association between weight gain and the following variables was investigated: age and gender of the recipient and the donor, donor type, steroid use, presence of systemic arterial hypertension (SAH) and diabetes mellitus, creatinine, glucose, cholesterol, and triglycerides. RESULTS: The study population included 203 recipients; 59.5% were males, their mean age systemic arterial hypertension (SAH) was 37 years, and 64.2% had deceased donors. In regard to immunosuppression, 41.3% made use of steroids. After 36 months of follow-up, the average weight gain was 6.6 kg in relation to the first month post-transplantation. Among the variables studied, the recipient's younger age and female gender, the younger donor, and the creatinine level were associated with greater weight gain after 36 months of transplantation. CONCLUSION: The percentage of weight gain was on average 9% after 36 months post-transplantation, although the prevalence of overweight and obesity increased significantly in the same period. The use of steroid therapy had no impact on the percentage of weight gain post-transplantation, and association was observed only between the younger age and the female gender of the recipient, the younger donor age, and the creatinine level with the highest weight gain post-transplantation.

Tuning plasmonic cloaks with an external magnetic field.

We propose a mechanism to actively tune the operation of plasmonic cloaks with an external magnetic field by investigating electromagnetic scattering by a dielectric cylinder coated with a magneto-optical shell. In the long wavelength limit, we show that the presence of a magnetic field may drastically reduce the scattering cross section at all observation angles. We demonstrate that the application of magnetic fields can modify the operation wavelength without the need of changing material and/or geometrical parameters. We also show that applied magnetic fields can reversibly switch on and off the cloak operation. These results, which could be achieved for existing magneto-optical materials, are shown to be robust to material losses, so that they may pave the way for developing actively tunable, versatile plasmonic cloaks.