Size Distribution of Superparamagnetic Particles Determined by Magnetic Sedimentation

We report on the use of magnetic sedimentation as a means to determine the size distribution of dispersed magnetic particles. The particles investigated here are i) single anionic and cationic nanoparticles of diameter D = 7 nm and ii) nanoparticle clusters resulting from electrostatic complexation with polyelectrolytes and polyelectrolyte-neutral copolymers. A theoretical expression of the sedimentation concentration profiles at the steady state is proposed and it is found to describe accurately the experimental data. When compared to dynamic light scattering, vibrating sample magnetometry and cryogenic transmission electron microscopy, magnetic sedimentation exhibits a unique property : it provides the core size and core size distribution of nanoparticle aggregates.Comment: 9 pages - templated ACS - 7 figures - 1 tabl

Interactions between sub-10 nm iron and cerium oxide nanoparticles and 3T3 fibroblasts : the role of the coating and aggregation state

Recent nanotoxicity studies revealed that the physico-chemical characteristics of engineered nanomaterials play an important role in the interactions with living cells. Here, we report on the toxicity and uptake of the cerium and iron oxide sub-10 nm nanoparticles by NIH/3T3 mouse fibroblasts. Coating strategies include low-molecular weight ligands (citric acid) and polymers (poly(acrylic acid), MW = 2000 g mol-1). Electrostatically adsorbed on the surfaces, the organic moieties provide a negatively charged coating in physiological conditions. We find that most particles were biocompatible, as exposed cells remained 100% viable relative to controls. Only the bare and the citrate-coated nanoceria exhibit a slight decrease of the mitochondrial activity for cerium concentrations above 5 mM (equivalent to 0.8 g L-1). We also observe that the citrate-coated particles are internalized by the cells in large amounts, typically 250 pg per cell after a 24 h incubation for iron oxide. In contrast, the polymer-coated particles are taken up at much lower rates (< 30 pg per cell). The strong uptake shown by the citrate-coated particles is related to the destabilization of the dispersions in the cell culture medium and their sedimentation down to the cell membranes. In conclusion, we show that the uptake of nanomaterials by living cells depends on the coating of the particles and on its ability to preserve the colloidal nature of the dispersions.Comment: 9 figures, 2 table

In vitro exploration of the synergistic effect of alternating magnetic field mediated thermo-chemotherapy with doxorubicin loaded dual pH- and thermo-responsive magnetic nanocomposite carriers

Nanoparticle induced hyperthermia has been considered as a promising approach for cancer treatment for decades. The local heating ability and drug delivery potential highlight a diversified possibility in clinical application, therefore a variety of nanoparticles has been developed accordingly. However, currently, only a few of them are translated into the clinical stage indicating a 'medically underexplored nanoparticles' situation, which encourages their comprehensive biomedical exploration. This study presents a thorough biological evaluation of previous well-developed dual pH- and thermo-responsive magnetic doxorubicin-nanocarriers (MNC-DOX) in multiple cancer cell lines. The cytotoxicity of the nanocomposites has been determined by the MTT assay on primary cell lines. Histology and fluorescence microscopy imaging revealed the efficiency of cellular uptake of nanocarriers in different cell lines. The IC50 of MNC-DOX is significantly higher than that of free DOX without an alternating magnetic field (AMF), which implied the potential to lower the systemic cytotoxicity in clinical research. The concurrent thermo-chemotherapy generated by this platform has been successfully achieved under an AMF. Promising effective synergistic results have been demonstrated through in vitro study in multi-model cancer cell lines via both trypan blue exclusion and bioluminescence imaging methods. Furthermore, the two most used magnetic hyperthermia modalities, namely intracellular and extracellular treatments, have been compared on the same nanocarriers in all 3 cell lines, which showed that treatment after internalization is not required but preferable. These results lead to the conclusion that this dual responsive nanocarrier has extraordinary potential to serve as a novel broad-spectrum anticancer drug and worth pursuing for potential clinical applications

In vitro exploration of the synergistic effect of alternating magnetic field mediated thermo-chemotherapy with doxorubicin loaded dual pH- and thermo-responsive magnetic nanocomposite carriers

Nanoparticle induced hyperthermia has been considered as a promising approach for cancer treatment for decades. The local heating ability and drug delivery potential highlight a diversified possibility in clinical application, therefore a variety of nanoparticles has been developed accordingly. However, currently, only a few of them are translated into the clinical stage indicating a 'medically underexplored nanoparticles' situation, which encourages their comprehensive biomedical exploration. This study presents a thorough biological evaluation of previous well-developed dual pH- and thermo-responsive magnetic doxorubicin-nanocarriers (MNC-DOX) in multiple cancer cell lines. The cytotoxicity of the nanocomposites has been determined by the MTT assay on primary cell lines. Histology and fluorescence microscopy imaging revealed the efficiency of cellular uptake of nanocarriers in different cell lines. The IC50 of MNC-DOX is significantly higher than that of free DOX without an alternating magnetic field (AMF), which implied the potential to lower the systemic cytotoxicity in clinical research. The concurrent thermo-chemotherapy generated by this platform has been successfully achieved under an AMF. Promising effective synergistic results have been demonstrated through in vitro study in multi-model cancer cell lines via both trypan blue exclusion and bioluminescence imaging methods. Furthermore, the two most used magnetic hyperthermia modalities, namely intracellular and extracellular treatments, have been compared on the same nanocarriers in all 3 cell lines, which showed that treatment after internalization is not required but preferable. These results lead to the conclusion that this dual responsive nanocarrier has extraordinary potential to serve as a novel broad-spectrum anticancer drug and worth pursuing for potential clinical applications

Motion of a deformable drop of magnetic fluid on a solid surface in a rotating magnetic field

The behavior of a magnetic fluid drop lying on a solid horizontal surface and surrounded by a nonmagnetic liquid under the action of a uniform magnetic field which is rotating in a vertical plane with low frequency (of the order of 1 Hz) has been investigated experimentally. Shape deformation and translatory motion of the drop were observed and studied. The drop translation velocity for different field amplitudes and field frequencies has been measured.Comment: 9 pages, 4 figure

Soliton ratchets

The mechanism underlying the soliton ratchet, both in absence and in presence of noise, is investigated. We show the existence of an asymmetric internal mode on the soliton profile which couples, trough the damping in the system, to the soliton translational mode. Effective soliton transport is achieved when the internal mode and the external force are phase locked. We use as working model a generalized double sine-Gordon equation. The phenomenon is expected to be valid for generic soliton systems.Comment: 4 pages, 4 figure

Porta-enxertos da série G (Geneva®) em área de replantio com 'MaxiGala'.

A necessidade de replantar áreas anteriormente cultivadas com macieiras vem se tomando frequente em toda a região Sul do Brasil, em função da elevada valorização que as áreas tiveram devido a expansão do cultivo da soja e da criação intensiva de gado. No município de Vacaria isso não é diferente, é muito comum um produtor de macieira erradicar um pomar velho, preparar o solo, cultivar uma gramínea por uma safra e retomar a plantar macieiras naquele mesmo local.bitstream/item/164129/1/Rufao-Agapomi-V279-P4-2017.pd

Cardiovascular complications related to cocaine use: case report

BACKGROUND AND OBJECTIVES: Cocaine is the most commonly used illicit drug and its acute and chronic effects are related to a variety of physiological changes, mainly in the cardiovascular system. This study is a case report of a patient with cardiomyopathy related to cocaine use. CASE REPORT: A 19 year old men, who has been using cocaine and crack since 15 years old, was admitted to the emergency department (ED) in February 2006 with progressive dyspnea during minimal efforts and bloody expectoration. During the physical exam it was observed legs edema, jugular stasis and dyspnea at rest. The echocardiogram demonstrated left ventricular hypocinesia, a 17 mm ventricular thrombus and a 12% ejection fraction. A bleeding from the left upper lobe was identified during a pulmonary bronchoscopy which was treated with arterial embolization. After 48h of the procedure, the patient was asymptomatic and an antithrombotic treatment with warfarin and enoxaparin was started. No obstruction was found at the cineangiography and the patient was discharged after clinical improvement. The patient was admitted again to the intensive care unit in July with intense chest pain and dyspnea at rest. A new cineangiography was performed and it was observed occlusion in the anterior descendent coronary artery. CONCLUSIONS: The cocaine acute effects are commonly seen at the ED but the chronic effects, as the cardiovascular manifestations, can take longer to be correlated as a side effect of cocaine use. Its prolonged use is related to left ventricular systolic dysfunction due to hypertrophy or myocardial dilation, atherosclerosis, arrhythmias, myocyte apoptosis and sympathetic damage.JUSTIFICATIVA E OBJETIVOS: A cocaína é uma droga ilícita amplamente utilizada e o seu uso tem sido associado a efeitos decorrentes da toxicidade aguda e crônica em praticamente todos os órgãos, particularmente no sistema cardiovascular. Este artigo visou descrever um caso de cardiomiopatia em paciente jovem usuário crônico de cocaína. RELATO DO CASO: Paciente do sexo masculino, 19 anos, usuário de cocaína por inalação e crack desde os 15 anos de idade. Foi internado em fevereiro de 2006 devido a dispnéia progressiva aos mínimos esforços e expectoração sanguinolenta. Ao exame físico apresentava edema nos membros inferiores, estase jugular e dispnéia em repouso. Foram observados no ecocardiograma: dilatação das quatro câmaras cardíacas, com hipocinesia difusa de ventrículo esquerdo (VE), trombo mural em VE de 17 mm e fração de ejeção de 12%. Realizada broncoscopia pulmonar que identificou sangramento em língula ativo, tratado com embolização. Após 48h do procedimento, o paciente manteve-se assintomático e sem expectoração sanguinolenta. Iniciado tratamento antitrombótico com warfarina e enoxaparina. A cineangiocoronariografia não evidenciou lesões obstrutivas e o paciente recebeu alta após melhora clínica. Re-internado em julho de 2006 com dor precordial de forte intensidade e dispnéia de repouso. Nova cineangiocoronariografia evidenciou oclusão de terço médio da artéria descendente anterior. CONCLUSÕES: Os efeitos agudos da cocaína freqüentemente motivam atendimento de emergência. Já as suas manifestações crônicas, como as doenças cardiovasculares, podem produzir alterações de difícil correlação futura ao seu consumo prévio. O uso prolongado da cocaína está relacionado à alteração da função sistólica ventricular esquerda por hipertrofia ou dilatação miocárdica, aterosclerose, disritmias cardíacas, apoptose de cardiomiócitos e lesão simpática.UNIFESPUniversidade São FranciscoUNIFESPSciEL

Lamin A/C truncation in dilated cardiomyopathy with conduction disease

BACKGROUND: Mutations in the gene encoding the nuclear membrane protein lamin A/C have been associated with at least 7 distinct diseases including autosomal dominant dilated cardiomyopathy with conduction system disease, autosomal dominant and recessive Emery Dreifuss Muscular Dystrophy, limb girdle muscular dystrophy type 1B, autosomal recessive type 2 Charcot Marie Tooth, mandibuloacral dysplasia, familial partial lipodystrophy and Hutchinson-Gilford progeria. METHODS: We used mutation detection to evaluate the lamin A/C gene in a 45 year-old woman with familial dilated cardiomyopathy and conduction system disease whose family has been well characterized for this phenotype [1]. RESULTS: DNA from the proband was analyzed, and a novel 2 base-pair deletion c.908_909delCT in LMNA was identified. CONCLUSIONS: Mutations in the gene encoding lamin A/C can lead to significant cardiac conduction system disease that can be successfully treated with pacemakers and/or defibrillators. Genetic screening can help assess risk for arrhythmia and need for device implantation