Nanoparticle size and 3D shape measurement by electron tomography: An Inter-Laboratory Comparison.

Electron tomography (ET) has been used for quantitative measurement of shape and size of objects in three dimensions (3D) for many years. However, systematic investigation of repeatability and reproducibility of ET has not been evaluated in detail. To assess the reproducibility and repeatability of a protocol for measuring size and three-dimensional (3D) shape parameters for nanoparticles (NPs) by ET, an inter-laboratory comparison (ILC) has been performed. The ILC included six laboratories and six instruments models from three instrument manufacturers following a standard measurement protocol. A technical specification describing the normative steps of the protocol is published by the International Standards Organization (ISO). Gold NPs with 30 nm nominal diameter contained within a rod-shaped carbon support were measured. The use of a rod-shaped sample support eliminated the missing wedge effect in the experimental tilt series of projected images for improved quantification. A total of 443 NPs were initially measured by NRC-NANO and then 115 out of the 443 NPs were measured by five other labs to compare measurands such as the Volume (V), maximum Feret diameter (Fmax), minimum Feret diameter (Fmin), volume-equivalent diameter (Deq) and aspect ratio (Frat) of the NPs. The results of the five labs were compared with the results obtained at NRC-NANO. The maximum disagreement in measurements of Fmin and Fmax obtained by the participating labs did not exceed 7 %. The measured Deq was between 27.5 nm and 30.3 nm in agreement with the NP manufacturer's specification (28 nm-32 nm). In addition to the above, the influence of the missing wedge effect and beam-induced NP movement was quantified based on the differences of the results between labs.

Valor da Ressonância Magnética Cardíaca no Diagnóstico e no Prognóstico de Pacientes com Infarto Agudo do Miocárdio sem Doença Arterial Coronariana Obstrutiva (MINOCA) / Value of Cardiac Magnetic Resonance in the Diagnosis and Prognosis of Patients with Acute Myocardial Infarction with Nonobstructive Coronary Artery Disease (MINOCA)

Fundamento: O infarto do miocárdio é uma das principais causas de morbimortalidade no mundo, e 13,2% dos pacientes com síndrome coronariana aguda apresentam coronárias sem obstrução significativa, denominada MINOCA (do inglês Myocardial Infarction with Non-Obstructive Coronary Artery, Infarto do Miocárdio sem Doença Coronariana Obstrutiva). Apesar do MINOCA ter evolução mais favorável que o infarto do miocárdio por obstrução coronariana, seu prognóstico não é benigno. A ressonância magnética cardíaca é o exame que apresenta importância no diagnóstico das diversas causas de MINOCA, e seu valor prognóstico não está completamente elucidado. Objetivo: Avaliar o valor prognóstico da ressonância magnética cardíaca na detecção de eventos adversos maiores em pacientes com MINOCA. Métodos: Coorte prospectiva por meio de coleta de dados de pacientes admitidos na urgência de pacientes com hospital terciário, diagnosticados com MINOCA, no período de 2012 a 2019. Resultados: Foram avaliados 179 pacientes com seguimento médio de 45 ± 21 meses, sendo 52% do sexo masculino, com idade média de 57,3 ± 15,5 anos. Observou-se incidência de eventos adversos maiores de 17,9%. A taxa de mortalidade ao final do acompanhamento foi de 3,8%. Na análise multivariada, apenas a ressonância magnética cardíaca com resultado normal se mostrou como preditor independente de bom prognóstico (hazard ratio: 0,09; intervalo de confiança de 95% 0,01- 0,88; p = 0,04), com curva de Kaplan-Meier apresentando diferença significativa (log-rank x2 = 9,83; p = 0,02) na predição de eventos adversos maiores. Conclusão: A ressonância magnética cardíaca normal mostrou-se como variável independente de bom prognóstico nessa população, podendo ser útil na estratificação de risco de pacientes com MINOCA.

Background: Myocardial infarction is one of the major causes of morbidity and mortality worldwide and 13.2% of patients with acute coronary syndrome have normal or unobstructed coronary arteries, called MINOCA (Myocardial Infarction with Non-Obstructive Coronary Artery). Cardiac magnetic resonance (CMR) is the gold standard for investigating the etiology of acute coronary syndrome. Although MINOCA has a more benign evolution than myocardial infarction due to coronary obstruction, its prognostic factors are not completely elucidated. Objective: To evaluate prognosis, predictive factors and describe the incidence of major adverse cardiovascular events in patients with MINOCA. Methods: Prospective cohort through data collection of patients admitted to the emergency department of a tertiary hospital, diagnosed with MINOCA from 2012 to 2019. The mean follow-up was 45 months, the outcomes considered were: death, rehospitalization due to cardiac causes, recurrence of chest pain, myocardial revascularization (MACE).

Tuning Magnetic Entropy Change and Relative Cooling Power in La0.7Ca0.23Sr0.07MnO3 Electrospun Nanofibers.

We present experimental evidence about the magnetocaloric tuning effect in one-dimensional nanostructure fibers mixed-valence manganite as synthesized by electrospinning techniques and under heat treatments of 973, 1073 and 1173 K. The stoichiometry obtained is La0.7Ca0.23Sr0.07MnO3 and Rietveld refinement indicates a single-phase with an orthorhombic (Pnma) crystal structure. Scanning and transmission electron microscopy observations indicate coalescence in granular colonies of La0.7Ca0.23Sr0.07MnO3 nanoparticles to conform nanofibers. Magnetic entropy change is tuned due to heat treatments at 1173 K with maximum values of 1, 1.82 and 2.51 J/kgK for applied external magnetic fields of µ0H = 1, 2 and 3T, respectively, with a maximum magnetic entropy difference at a Curie temperature of 293 K (furthermore, second-order magnetic phase transition was observed). Additionally, for a magnetic field, ~µ0H = 3 T values of 49, 95 and 143 J/kg for 973, 1073 and 1173 K heat-treated samples were obtained.

Síndrome de Peutz-Jeghers: novos dados e bases moleculares sobre uma doença rara / The Peutz-Jeghers syndrome: new data and molecular bases on a rare disease

A síndrome de Peutz-Jeghers é uma associação de polipose no trato gastrointestinal do tipo familiar e pigmentação melânica mucocutânea, particularmente nos lábios, mucosa bucal e polpa digital. Há poucas décadas, algumas centenas de casos haviam sido descritos na literatura, o que torna a doença não tão rara. O objetivo deste trabalho foi relatar casos clínicos em que os pacientes eram portadores da síndrome. Em um dos casos, tia e sobrinha evidenciaram a implicação genética da doença. Dados clínicos, bases moleculares e resultados histopatológicos, com a utilização de anticorpos (Ac) monoclonais, mostram a relevância do trabalho. Portadores crônicos da síndrome após décadas, ainda não diagnosticados, procuram o cirurgião-dentista para tratamentos diversos, dando-lhe oportunidade e responsabilidade na detecção da doença, devido ao risco de desenvolvimento de tumores malignos no trato gastrointestinal.

The Peutz-Jeghers syndrome is a familiar association of polyposis in the gastrointestinal tract and melanic mucocutaneous pigmentation, particularly in the lips, oral mucosa and fi ngertips. A few decades few hundred cases had been described in the literature wich makes the disease not so rare. The objective of this study is to report clinical cases where patients were carriers of the syndrome. In one of the cases the aunt and nice showed the genetic implication of the disease. Clinical data, molecular basis and histopathological results with monoclonal antibodies (Ac), show the relevance of this work. Chronic carriers of the syndrome after decades, still undiagnosed, seek the dentist for various treatments giving him the opportunity and responsibility to detect the disease due to the risk of development of malignant tumors in the gastrointestinal tract.

Valor do Strain Bidimensional no Diagnóstico da Miocardite Aguda: Comparação com a Ressonância Cardíaca / The Value of Two-dimensional Strain in the Diagnosis of Acute Myocarditis: Comparison with Cardiac Magnetic Resonance Imaging

Fundamento: A miocardite aguda é uma das principais causas de morte súbita em pacientes jovens. A ressonância magnética cardíaca (RMC) é um método sensível e não invasivo para detecção de miocardite, mas de alto custo e indisponível na maioria dos centros médicos. O strain bidimensional representa uma nova técnica ecocardiográfica que possibilita a avaliação da deformação miocárdica permitindo a análise da função miocárdica global e regional. Objetivo: Avaliar o valor do strain bidimensional em pacientes com diagnóstico de miocardite. Materiais e métodos: Foram estudados prospectivamente pacientes com quadro de miocardite aguda e contratilidade cardíaca normal pela RMC e submetidos à ecocardiografia convencional e strain bidimensional. O miocárdio ventricular foi dividido em 16 segmentos e esses segmentos divididos em dois grupos. Grupo 0: segmento miocárdico normal pela RMC. Grupo 1: segmento miocárdico compatível com miocardite pela RMC. Resultados: Foram avaliados 28 pacientes sendo 82,1% do sexo masculino, com idade de 35,6 ± 8,9 anos. Dos 448 segmentos miocárdicos avaliados, 316 segmentos foram normais (grupo 0) e 132 segmentos (grupo 1) apresentaram diagnóstico de miocardite pela técnica de realce tardio à RMC. A análise do strain bidimensional mostrou diferença significativa entre os grupos (19,6 ± 2,9 versus 15,4 ± 2,8 p = 0,001), com sensibilidade 75% e especificidade 79% e AUC de 0,86 (IC 95% 0,82 a 0,89). Conclusão: O strain bidimensional pode ser útil na avaliação propedêutica de pacientes com miocardite e contratilidade normal pela RMC e ecocardiografia convencional

Background: Acute myocarditis is one of the most important causes of sudden death in young people. Cardiac magnetic resonance (CMR) is a sensitive and non-invasive method in myocarditis diagnosis, but it is expensive and unavailable in most medical centers. Speckle tracking strain echocardiography is a new echocardiographic technique that enables the evaluation of myocardial deformation allowing analysis of global and regional myocardial function. Objective: To evaluate the value of speckle tracking strain echocardiography in patients with acute myocarditis and normal wall motion contraction. Materials and Methods: We prospectively studied patients with acute myocarditis and normal cardiac contractility by CMR and underwent conventional echocardiography and speckle tracking strain echocardiography. The ventricular myocardium was divided into 16 segments by CMR and echocardiography and separated into two groups: Normal myocardial segment (group 1) myocardial segment compatible with myocarditis (group 1). Results: We evaluated 28 patients (82.1% male), aged 35.6 ± 8.9 years. Of the 448 myocardial segments evaluated, 316 segments were normal (group 0) and 132 segments (group 1) were diagnosed with myocarditis by RMC. Speckle tracking strain echocardiography showed a significant difference between groups (-19.6 ± 2.9 versus -15.4 ± 2.8 p = 0.001), with sensitivity of 75% and specificity of 79% with AUC of 0.86 (95% CI 0.82 to 0.89). Conclusion: Speckle tracking strain echocardiography can be useful in the diagnosis evaluation of patients with myocarditis and normal contractility by CMR and conventional echocardiography