Modeling the Magnetic-Hyperthermia Response of Linear Chains of Nanoparticles with Low Anisotropy: A Key to Improving Specific Power Absorption

The effect of magnetic interactions is a key issue for the performance of nanoparticles in magnetic fluid hyperthermia. There are reports informing on beneficial or detrimental effects in terms of the specific power absorption depending on the intrinsic magnetic properties and the spatial arrangement of the nanoparticles. To understand this effect, our model treats a simple system: an ensemble of identical nanoparticles arranged in an ideal chain with the easy axis of the effective uniaxial anisotropy of each particle aligned parallel to the chain. We study the magnetic relaxation of linear chains with low anisotropy in magnetic-fluid-hyperthermia experiments, a system that yields a larger hysteresis area than the noninteracting case (i.e., improved specific power absorption) for all orientations of the chain (even in the perpendicular configuration and the randomly oriented case). The most-favorable case is the chain parallel to the external field; however, we show that the incorporation of a dipolar-field component perpendicular to the external field is necessary for the correct modeling of chains nearly in the perpendicular configuration, which is not always done. The mechanism involved in the hysteresis-area increase can be interpreted as a shift between the local field and the applied field.Fil: Valdés, Daniela Paola. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia - Nodo Bariloche | Comision Nacional de Energia Atomica. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia - Nodo Bariloche.; ArgentinaFil: Lima, Enio Junior. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología - Nodo Bariloche | Comisión Nacional de Energía Atómica. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología - Nodo Bariloche; ArgentinaFil: Zysler, Roberto Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología - Nodo Bariloche | Comisión Nacional de Energía Atómica. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología - Nodo Bariloche; ArgentinaFil: de Biasi, Emilio. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia - Nodo Bariloche | Comision Nacional de Energia Atomica. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia - Nodo Bariloche.; Argentin

Resistance of endodontically treated roots restored with different fibre post systems with or without post space preparation: in vitro analysis and SEM investigation.

Aim: To compare the mechanical resistance to fracture of two conical post systems placed with no preparation of the root canal with that of double taper fibre posts seated in endodontically treated single roots after standard post space preparation using dedicated drills. Methodology: Thirty fibre posts with double (G1, n = 10, DT Light Post) and single taper (G2, n = 10, SurgiPost Multiconical; G3, n = 10, Tech ES Endoshape) were luted with self-adhesive cement in endodontically treated single roots using different post space preparation techniques. The bonded posts were experimentally loaded until failure and the maximum load to fracture was registered. Fracture patterns were qualitatively evaluated and SEM analysis was performed to assess the quality of endodontic treatments and cementation. Data were statistically analysed by means of one-way ANOVA. Results: The mean maximum load to fracture was 165.05 23.46 N in G1, 151.52 16.23 N in G2 and 129.09 15.25 N in G3. Statistically significant differences were pointed out between G1 and G3 (p < 0.01) and G2 and G3 (p < 0.05). No root fractures were evidenced. SEM analyses showed slightly thicker cement ayers at the apical and middle thirds of single taper posts (G2 and G3). Conclusions: DT Light Post and SurgiPost Multiconical fibre posts showed similar properties in terms of mechanical resistance to fracture and higher than those of Tech ES Endoshape. Unrestorable root fractures did not occur with any of the tested posts

Superficial loss of reactive phosphorus potentially contaminant by intense rainfall simulation

O fósforo naturalmente presente ou adicionado ao solo, dependendo da conjunção de fatores, pode desencadear uma situação de alto risco ambiental para os recursos hídricos de bacias hidrográficas. O objetivo deste trabalho foi quantificar a transferência na superfície do solo de algumas formas de fósforo reativo, originário da adubação fosfatada em solo sem cultivo e descoberto, transportado pelo escoamento superficial da água de chuvas. O experimento foi executado em Lages, SC, com duas repetições de campo, sob regime de chuvas intensas simuladas (64 mm h−1 durante 50 minutos). Os resultados apontam que o fósforo pode representar sério risco ambiental aos recursos hídricos das bacias, em diferentes escalas no tempo e no espaço, através das formas reativas de fósforo e suas diferentes maneiras de transporte.Phosphorus is naturally present or added to the soil and, depending on the mix of factors, may trigger a high environmental risk to water resources in river basins. The aim of this study was to quantify the transfer for soil surface of some forms of reactive phosphorus originating from phosphorus fertilization on bare soil, carried by the runoff. The experiment was carried out in Lages, SC, Brazil, with two replications in the field under intense simulated rainfall (64 mm h−1 for 50 minutes). The results indicate that phosphorus may represent a serious environmental risk to water resources of basins at different scales in time and space, through the reactive forms of phosphorus and their different ways of transportation

Novel genetic association of TNF-α-238 and PDCD1-7209 polymorphisms with long-term non-progressive HIV-1 infection.

About 2-5% of HIV-1-infected subjects, defined as long-term non-progressors (LTNPs), remain immunologically stable for a long time without treatment. The factors governing this condition are known only in part, and include genetic factors. Thus, we studied 20 polymorphisms of 15 genes encoding proinflammatory and immunoregulatory cytokines, chemokines and their receptors, genes involved in apoptosis, and the gene HCP5. METHODS: We analyzed 47 Caucasian LTNPs infected for &gt;9 years, compared with 131 HIV-1-infected Caucasian patients defined as 'usual progressors'. The genotypes were determined by methods based upon PCR, and the statistical analysis was performed by univariate logistic regression. RESULTS: The well-known CCR5Δ32 del32 allele, the cell death-related TNF-α-238 A and PDCD1-7209 T alleles, and HCP5 rs2395029 G, a non-coding protein associated with the HLA-B*5701, were found positively associated with the LTNP condition. No association was observed for other single nucleotide polymorphisms (SDF-1-801, IL-10-592, MCP-1-2518, CX3CR1 V249I, CCR2V64I, RANTES-403, IL-2-330, IL-1β-511, IL-4-590, FASL IVS3nt-169, FAS-670, FAS-1377, FASL IVS2nt-124, PDCD1-7146, MMP-7-181, and MMP7-153). CONCLUSIONS: The novel genetic associations between allelic variants of genes TNF-α-238 and PDCD1-7209 with the LTNP condition underline the importance of host genetic factors in the progression of HIV-1 infection and in immunological preservation

Monocytic population in chronic lymphocytic leukemia shows altered composition and deregulation of genes involved in phagocytosis and inflammation

Macrophages reside in tissues infiltrated by chronic lymphocytic leukemia B-cells and the extent of infiltration is associated with adverse prognostic factors. Blood monocyte population was studied by flow cytometry and whole-genome microarrays. A mixed lymphocyte reaction was performed to evaluate T cell proliferation in contact with monocytes from patients and normal donors. Migration and gene modulation in normal monocytes treated with leukemia were also evaluated. Chronic lymphocytic leukemia patients showed an increase in the absolute number of monocytes compared to normal controls (792+/-86 cells/mL vs. 485+/-46 cells/mL, p=0.003). Higher number of nonclassical CD14+CD16++ and Tie-2 expressing monocytes (TEMs) was also detected in patients. Furthermore, we performed a gene expression analysis of monocytes in chronic lymphocytic leukemia patients, showing up-regulation of RAP1GAP and down-regulation of tubulins and CDC42EP3, which would be expected to result in impairment in phagocytosis. We also detected gene alterations such as the down-regulation of PTGR2, a reductase able to inactivate the prostaglandin E2, indicating an immunosuppressive activity. Accordingly, T cell proliferation was inhibited in contact with monocytes from patients compared to normal controls. Finally, normal monocytes in vitro increased migration and up-regulated CD16, RAP1GAP, IL-10, IL-8, MMP9 and down-regulated PTGR2 in response to leukemic cells or conditioned media. In conclusion, altered composition and deregulation of genes involved in phagocytosis and inflammation were found in blood monocytes obtained from chronic lymphocytic leukemia patients, suggesting that leukemia-mediated 'education' of immune elements may also include the establishment of a skewed phenotype in monocyte/macrophage population

Whole-body low-dose CT recognizes two distinct patterns of lytic lesions in multiple myeloma patients with different disease metabolism at PET/MRI

We evaluated differences in density and 18F-FDG PET/MRI features of lytic bone lesions (LBLs) identified by whole-body low-dose CT (WB-LDCT) in patients affected by newly diagnosed multiple myeloma (MM). In 18 MM patients, 135 unequivocal LBLs identified by WB-LDCT were characterized for inner density (negative or positive Hounsfield unit (HU)), where negative density (HU\u2009<\u20090) characterizes normal yellow marrow whereas positive HU correlates with tissue-like infiltrative pattern. The same LBLs were analyzed by 18F-FDG PET/DWI-MRI, registering DWI signal with ADC and SUV max values. According to HU, 35 lesions had a negative density (-\u200956.94\u2009\ub1\u200931.87 HU) while 100 lesions presented positive density (44.87\u2009\ub1\u200923.89 HU). In seven patients, only positive HU LBLs were demonstrated whereas in eight patients, both positive and negative HU LBLs were detected. Intriguingly, in three patients (16%), only negative HU LBLs were shown. At 18F-FDG PET/DWI-MRI analysis, negative HU LBLs presented low ADC values (360.69\u2009\ub1\u2009154.38\u2009 7\u200910-6 mm2/s) and low SUV max values (1.69\u2009\ub1\u20090.56), consistent with fatty marrow, whereas positive HU LBLs showed an infiltrative pattern, characterized by higher ADC (mean 868.46\u2009\ub1\u2009207.67\u2009 7\u200910-6 mm2/s) and SUV max (mean 5.04\u2009\ub1\u20091.94) values. Surprisingly, histology of negative HU LBLs documented infiltration by neoplastic plasma cells scattered among adipocytes. In conclusion, two different patterns of LBLs were detected by WB-LDCT in MM patients. Both types of lesions were indicative for active disease, although only positive HU LBL were captured by 18F-FDG PET/DWI-MRI imaging, indicating that WB-LDCT adds specific information

Free-Radical Formation by the Peroxidase-Like Catalytic Activity of MFe2O4 (M = Fe, Ni, and Mn) Nanoparticles

Ferrite magnetic nanoparticles (MNPs) have peroxidase-like activity and thus catalyze the decomposition of H2O2-producing reactive oxygen species (ROS). Increasingly important applications of these ferrite MNPs in biology and medicine require that their morphological, physicochemical, and magnetic properties need to be strictly controlled. Usually, the tuning of their magnetic properties is achieved by the replacement of Fe by other 3d metals, such as Mn or Ni. Here, we studied the catalytic activity of ferrite MNPs (MFe2O4, M = Fe2+/Fe3+, Ni, and Mn) with the mean diameter ranging from 10 to 12 nm. Peroxidase-like activity was studied by electron paramagnetic resonance (EPR) using the spin-trap 5,5-dimethyl-1-pyrroline N-oxide at different pHs (4.8 and 7.4) and temperatures (25 and 40 °C). We identified an enhanced amount of hydroxyl (•OH) and perhydroxyl (•OOH) radicals for all samples, compared to a blank solution. Quantitative studies show that [•OH] is the dominant radical formed for Fe3O4, which is strongly reduced with the concomitant oxidation of Fe2+ or its substitution (Ni or Mn). A comparative analysis of the EPR data against in vitro production of ROS in microglial BV2 cell culture provided additional insights regarding the catalytic activity of ferrite MNPs, which should be considered if biomedical uses are intended. Our results contribute to a better understanding of the role played by different divalent ions in the catalytic activity of ferrite nanoparticles, which is very important because of their use in biomedical applications.Fil: Moreno Maldonado, Ana Carolina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; ArgentinaFil: Winkler, Elin Lilian. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología - Nodo Bariloche | Comisión Nacional de Energía Atómica. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología - Nodo Bariloche; ArgentinaFil: Raineri Andersen, Mariana. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia - Nodo Bariloche | Comision Nacional de Energia Atomica. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia - Nodo Bariloche.; ArgentinaFil: Toro Córdova, Alfonso. Universidad de Zaragoza; EspañaFil: Rodriguez, Luis Miguel. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia - Nodo Bariloche | Comision Nacional de Energia Atomica. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia - Nodo Bariloche.; ArgentinaFil: Troiani, Horacio Esteban. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Mojica Pisciotti, Mary Luz. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia - Nodo Bariloche | Comision Nacional de Energia Atomica. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia - Nodo Bariloche.; ArgentinaFil: Vasquez Mansilla, Marcelo. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia - Nodo Bariloche | Comision Nacional de Energia Atomica. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia - Nodo Bariloche.; ArgentinaFil: Tobia, Dina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia - Nodo Bariloche | Comision Nacional de Energia Atomica. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia - Nodo Bariloche.; ArgentinaFil: Nadal, Marcela. Comisión Nacional de Energía Atómica. Gerencia del Área de Investigación y Aplicaciones No Nucleares. Gerencia de Física. Laboratorio de Resonancias Magnéticas; Argentina. Comisión Nacional de Energía Atómica. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología; ArgentinaFil: Torres Molina, Teobaldo Enrique. Comisión Nacional de Energía Atómica. Gerencia del Área de Investigación y Aplicaciones No Nucleares. Gerencia de Física. Laboratorio de Resonancias Magnéticas; Argentina. Comisión Nacional de Energía Atómica. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología; ArgentinaFil: de Biasi, Emilio. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia - Nodo Bariloche | Comision Nacional de Energia Atomica. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia - Nodo Bariloche.; ArgentinaFil: Ramos, Carlos A.. Comisión Nacional de Energía Atómica. Gerencia del Área de Investigación y Aplicaciones No Nucleares. Gerencia de Física. Laboratorio de Resonancias Magnéticas; ArgentinaFil: Goya, Gerardo Fabian. Universidad de Zaragoza; EspañaFil: Zysler, Roberto Daniel. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia - Nodo Bariloche | Comision Nacional de Energia Atomica. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia - Nodo Bariloche.; ArgentinaFil: Lima, Enio Junior. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia - Nodo Bariloche | Comision Nacional de Energia Atomica. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia - Nodo Bariloche.; Argentin