264 research outputs found

    Improving the room-temperature ferromagnetism in ZnO and low-doped ZnO:Ag films using GLAD sputtering

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    ZnO and doped ZnO films with non-ferromagnetic metal have been widely used as biosensor elements. In these studies, the electrochemical measurements are explored, though the electrical impedance of the system. In this sense, the ferromagnetic properties of the material can be used for multifunctionalization of the sensor element using external magnetic fields during the measurements. Within this context, we investigate the room-temperature ferromagnetism in pure ZnO and Ag-doped ZnO films presenting zigzag-like columnar geometry. Specifically, we focus on the films’ structural and quasi-static magnetic properties and disclose that they evolve with the doping of low-Ag concentrations and the columnar geometry employed during the deposition. The magnetic characterization reveals ferromagnetic behavior at room temperature for all studied samples, including the pure ZnO one. By considering computational simulations, we address the origin of ferromagnetism in ZnO and Ag-doped ZnO and interpret our results in terms of the Zn vacancy dynamics, its substitution by an Ag atom in the site, and the influence of the columnar geometry on the magnetic properties of the films. Our findings bring to light an exciting way to induce/explore the room-temperature ferromagnetism of a non-ferromagnetic metal-doped semiconductor as a promising candidate for biosensor applications.This works was partially supported by the Brazilian agencies CNPq and CAPES. Furthermore, this work was also supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2019 and project PTDC/BTMMAT/28237/2017. A. Ferreira thanks FCT for the contract under the Stimulus of Scientific Employment (CTTI-31/18–CF (2) junior researcher contract). RMT thanks the Center for Computational Engineering & Sciences (CCES) at Unicamp for financial support through the FAPESP/CEPID Grant 2013/08293-7. LDM would also like to thank the support of the High-Performance Computing Center at UFRN (NPAD/UFRN). The work reported in this paper was supported by On-Surf Mobilizar Competencias Tecnologicas em Engenharia de Superficies, Project POCI-01-0247-FEDER-024521

    Characteristics of Community-Associated Methicillin-Resistant Staphylococcus aureus (CA-MRSA) Strains Isolated from Skin and Soft-Tissue Infections in Uruguay

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    We analyzed 90 nonduplicates community-associated methicillin-resistant S. aureus (CA-MRSA) strains isolated from skin and soft-tissue infections. All strains were mecA positive. Twenty-four of the 90 strains showed inducible macrolide-lincosamide-streptogramin B resistance. All strains produced α-toxin; 96% and 100% of them displayed positive results for lukS-F and cna genes, respectively. Eigthy-five strains expressed capsular polysaccharide serotype 8. Six different pulsotypes were discriminated by pulsed-field gel electrophoresis (PFGE) and three predominant groups of CA-MRSA strains (1, 2, and 4) were identified, in agreement with phenotypic and genotypic characteristics. Strains of group 1 (pulsotype A, CP8+, and Panton-Valentine leukocidin (PVL)+) were the most frequently recovered and exhibited a PFGE band pattern identical to other CA-MRSA strains previously isolated in Uruguay and Brazil. Three years after the first local CA-MRSA report, these strains are still producing skin and soft-tissue infections demonstrating the stability over time of this community-associated emerging pathogen

    On the bioactivity of Echinacea purpurea extracts to modulate the production of inflammatory mediators

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    Inflammatory diseases are the focus of several clinical studies, due to limitations and serious side effects of available therapies. Plant-based drugs (e.g., salicylic acid, morphine) have become landmarks in the pharmaceutical field. Therefore, we investigated the immunomodulatory effects of flowers, leaves, and roots from Echinacea purpurea. Ethanolic (EE) and dichloromethanolic extracts (DE) were obtained using the Accelerated Solvent Extractor and aqueous extracts (AE) were prepared under stirring. Their chemical fingerprint was evaluated by liquid chromatography–high resolution mass spectrometry (LC-HRMS). The pro- and anti-inflammatory effects, as well as the reduction in intracellular reactive oxygen and nitrogen species (ROS/RNS), of the different extracts were evaluated using non-stimulated and lipopolysaccharide-stimulated macrophages. Interestingly, AE were able to stimulate macrophages to produce pro-inflammatory cytokines (tumor necrosis factor -TNF-α, interleukin -IL-1β, and IL-6), and to generate ROS/RNS. Conversely, under an inflammatory scenario, all extracts reduced the amount of pro-inflammatory mediators. DE, alkylamides-enriched extracts, showed the strongest anti-inflammatory activity. Moreover, E. purpurea extracts demonstrated generally a more robust anti-inflammatory activity than clinically used anti-inflammatory drugs (dexamethasone, diclofenac, salicylic acid, and celecoxib). Therefore, E. purpurea extracts may be used to develop new effective therapeutic formulations for disorders in which the immune system is either overactive or impaired.This research was funded by the Fundação para a Ciência e a Tecnologia (FCT) to the PhD grant of SFV (PD/BD/135246/2017 and COVID/BD/152012/2021) and the projects PATH (PD/00169/2013), FROnTHERA (NORTE-01-0145-FEDER-000023), Cells4_IDs (PTDC/BTM-SAL/28882/2017), and the NORTE 2020 Structured Project, co-funded by Norte2020 (NORTE-01-0145-FEDER-000021). This research was also partially supported by national funds by FCT through the projects UIDB/04423/2020 and UIDP/04423/2020 (Group of Natural Products and Medicinal Chemistry-CIIMAR) and ERDF, through the COMPETE—POFC program in the framework of the program PT2020

    Radiomic analysis of MRI to Predict Sustained Complete Response after Radiofrequency Ablation in Patients with Hepatocellular Carcinoma - A Pilot Study

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    OBJECTIVES: To investigate whether quantitative textural features, extracted from pretreatment MRI, can predict sustained complete response to radiofrequency ablation (RFA) in patients with hepatocellular carcinoma (HCC). METHODS: In this IRB-approved study, patients were selected from a maintained six-year database of consecutive patients who underwent both pretreatment MRI imaging with a probable or definitive imaging diagnosis of HCC (LI-RADS 4 or 5) and loco-regional treatment with RFA. An experienced radiologist manually segmented the hepatic nodules in MRI arterial and equilibrium phases to obtain the volume of interest (VOI) for extraction of 107 quantitative textural features, including shape and first- and second-order features. Statistical analysis was performed to evaluate associations between textural features and complete response. RESULTS: The study consisted of 34 patients with 51 treated hepatic nodules. Sustained complete response was achieved by 6 patients (4 with single nodule and 2 with multiple nodules). Of the 107 features from the arterial and equilibrium phases, 20 (18%) and 25 (23%) achieved AUC >0.7, respectively. The three best performing features were found in the equilibrium phase: Dependence Non-Uniformity Normalized and Dependence Variance (both GLDM class, with AUC of 0.78 and 0.76, respectively) and Maximum Probability (GLCM class, AUC of 0.76). CONCLUSIONS: This pilot study demonstrates that a radiomic analysis of pre-treatment MRI might be useful in identifying patients with HCC who are most likely to have a sustained complete response to RFA. Second-order features (GLDM and GLCM) extracted from equilibrium phase obtained highest discriminatory performance

    The influence of behavioral enrichment on dry food consumption by the black tufted-ear marmoset, Callithrix penicillata (Mammalia: Callithricidae): a pilot study

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    Stereotyped behaviors in captive primates are often caused by unsuitable conditions. Environmental enrichment has been used to reduce these behaviors, and also to increase the frequency of behaviors appropriate to the species. In this pilot study we evaluated whether behavioral enrichment influences food intake by the black tufted-ear marmoset, Callithrix penicillata (É. Geoffroy Saint-Hilaire, 1812), by calculating energy maintenance requirements. We evaluated 16 individually housed, healthy adult black tufted-ear marmosets, randomly divided into two treatment groups, one with behavioral enrichment and one without. The enrichment techniques included structural aspects, such as placing fixed and mobile objects in the cage and supplying dry foods in an enriched form, in order to stimulate cognition. Based on the metabolic weight of the animals, we calculated the energy requirements for their maintenance. The animals that received behavioral enrichment consumed more food than those that did not. We also observed that the animals that did not receive enrichment consumed 9.85% less food than had been calculated for energy maintenance requirements, while the animals that received enrichment consumed 24.97% more food than had been calculated. Results indicate that the use of behavioral enrichment items raised the energy requirements of the black tufted-ear marmoset and, therefore, the consumption of dry food, suggesting that environmental enrichment plays a role in stimulating food consumption. This conclusion should alert scientists, technicians and primatologists to the importance of controlling body weight of marmosets when introducing environmental enrichment to avoid overfeeding and obesity. To verify this conclusion, a study is needed with a longer time frame and more parameters, such as behavior observation and body weight

    Actividad de acetilcolinesterasa y niveles totales de antioxidantes en perros con tumores de mama antes y después de la extirpación quirúrgica

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    Objective. The aim of this study was to evaluate AChE activity in total blood and the FRAP levels in samples from dogs with mammary tumors before and after surgery, as well as the relationship between these variables with immunohistochemical markers of tumor (E-caderina, ki-67, COX-2). Materials and methods. In this study, 13 dogs with mammary tumors were divided into two groups (A and B). The group A was formed by dogs with tumors smaller than 3 cm of diameter, and the group B was formed by dogs with tumor of 3 cm of diameter or larger. The AChE activity and FRAP levels were evaluated before and after surgery and the immunohistochemistry were performed at the tumors. Results. The AChE activity was significantly increased (p<0.05) in dogs with mammary cancer compared to control animals, and neither surgery or tumor size affected the AChE activity (p>0.05). FRAP levels before surgery were significantly lower (p<0.05) compared to control animals. Also, FRAP levels increased significantly after surgery in animals of the group A compared to data before surgery, a fact not observed in dogs from the group B. E-cadherin showed low significant positive correlation with FRAP levels (r=0.37, P-value=0.05); COX-2 showed a moderate significant positive correlation to FRAP (r=0.55, P-value<0.05); and COX-2 showed a low significant positive correlation to AChE (r=0.32, P-value=0.01). Conclusions. AChE and antioxidant levels are modified in dogs with mammary cancer. These variables are involved in various physiological functions, and thus, they might be related to disease pathogenesis.Objetivo. El objetivo de este estudio fue evaluar la actividad de la AChE en sangre total y los niveles de FRAP en muestras de perros con tumores mamarios antes y después de la cirugía, así como la relación entre estas variables con marcadores inmunohistoquímicos de tumores (E-caderina, ki-67 , COX - 2). Materiales y métodos. En este estudio, 13 perros con tumores mamarios se dividieron en dos grupos (A y B). El grupo A estaba formado por perros con tumores menores de 3 cm de diámetro y el grupo B estaba formado por perros con tumor de 3 cm de diámetro o más. La actividad de AChE y los niveles de FRAP se evaluaron antes y después de la cirugía y la inmunohistoquímica se realizó en los tumores. Resultados. La actividad de la AChE aumentó significativamente (p <0,05) en perros con cáncer mamario en comparación con los animales control, y ni la cirugía ni el tamaño tumoral afectaron la actividad de la AChE (p> 0,05). Los niveles de FRAP antes de la cirugía fueron significativamente más bajos (p <0,05) en comparación con los animales control. Además, los niveles de FRAP aumentaron significativamente después de la cirugía en animales del grupo A en comparación con los datos antes de la cirugía, hecho que no se observó en perros del grupo B. La E-cadherina mostró correlación positiva baja con los niveles de FRAP (r = 0,37, valor P = 0,05); COX-2 mostró una moderada correlación positiva significativa con FRAP (r = 0,55, P-valor <0,05); Y la COX-2 mostró una correlación positiva de baja significación con la AChE (r = 0.32, P-valor = 0.01). Conclusiones. AChE y los niveles de antioxidantes se modifican en perros con cáncer de mama. Estas variables están implicadas en diversas funciones fisiológicas, y por lo tanto, pueden estar relacionadas con la patogénesis de la enfermedad
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