O Estado da arte da cromatografia líquida bidimensional: conceitos fundamentais, instrumentação e aplicações

The constant evolution of science and the growing demand for new technologies have led to new techniques in instrumentation that can improve detection, separation, resolution, and peak capacity. Comprehensive two-dimensional liquid chromatography (LC×LC) is presented as a powerful tool in complex sample analyses. During an analysis, a sample is subjected to two independent separation mechanisms that are combined, resulting in increased resolving power. For appropriate application of LC×LC, understanding the influence of parameters that require optimization is necessary. The main purpose of optimization is to predict the combination of stationary phases, separation conditions, and instrumental requirements to obtain the best separation performance. This review discusses theoretical, intrumental, and chemometric aspects of LC×LC and focuses on its applications in foods. It aims to provide a clear understanding of the aspects that can be used as strategies in the optimization of this analytical method.

O ESTADO DA ARTE DA LIGAÇÃO DE HIDROGÊNIO

Along the historical background of science, the hydrogen bond became widely known as the universal interaction, thus playing a key role in many molecular processes. Through the available theoretical approaches, many of these processes can be unveiled on the basis of the molecular parameters of the subject intermolecular system, such as the variation of bond length and mainly the frequency shift observed in the proton donor. Supported by the natural bond analysis (NBO) with the quantification of the hybridization contributions, the structural deformations and vibrational effects cited above are also attributed to the outcome of the intermolecular interaction strength, which consequently can be estimated by means of the quantum theory of atoms in molecules (QTAIM) as well as evaluated by the symmetry-adapted perturbation theory (SAPT). Moreover, to identify the preferential interaction sites for proton donors and acceptors, the molecular electrostatic potential (MEP) is useful in this regard.

CROMATOGRAFIA POR INTERAÇÕES HIDROFILICAS (HILIC): ESTADO DA ARTE E APLICAÇÕES

Hydrophilic interaction liquid chromatography (HILIC) has been gaining increased attention for its effective separation of highly polar compounds, which include carbohydrates, amino acids, pharmaceutical compounds, proteins, glycoproteins, nucleosides, etc. Polar compounds are usually poorly retained on reverse-phase liquid chromatography (RP-HPLC) columns or have poor solubility in the apolar mobile phase of normal-phase high performance liquid chromatography (NP-HPLC). Since HILIC uses organic solvents such as ACN or MeOH ( > 70%), also used in RP-HPLC and polar stationary phases similar to NP-HPLC (bare silica, diol, amino, amide, saccharide, zwitterionic stationary phases, etc.), it represents a hybrid of the two separation modes. The high organic content in the MP leads to good compatibility with mass spectrometry (MS), increasing the detectivity. This review describes the fundamentals of HILIC and highlights some interesting applications.

O estado da arte da cirurgia do baço, no início do século XXI

In the last fifty years evolution of scientific knowledge on the spleen provoked an entirely new approach to splenic surgery. It was shown that virulence may emerge as a significant consequence of environmental and evolutionary changes of some microbial communities, and devastating pathogenetic results of these changes become visible in human hosts without the splenic function. In other words: the spleen plays a pivotal role in the dynamic balance between biodiversity, microorganisms and immunogenecity in human hosts. Therefore, to preserve the "splenic immunologic repertoire" became an increasing commitment among surgeons. Understanding the integration of these multiple information on spleen, seems central to understand the new splenic surgery. Partial splenectomies (Réglées) - based on anatomical, experimental and clinical studies, developed at the University of Minas Gerais since the fifties - were successfully applied initially to treat the traumatic injuries of the spleen; in a following step, partial splenectomy were used to control hematological diseases. "Réglées" techniques on the spleen have conquered "ethical support, consilience status and clinical governance" to give birth to surgical therapeutic decisions on the spleen, in order to spare the structural integrity of the immune system. Splenic réglées procedures became a seminal achievement of splenic surgical practice. Initial results of "Partial splenectomies" - with conventional surgical armamentaria and techniques - were confirmed and improved by the introduction of techniques based on laparoscopic and endovascular approaches. And current usage of surgical splenic saving procedures propitiated the emergence of an appropriate lexicon for medical communication and became an "end point" of a "long-standing surgical inhibition" over the spleen.

Videocirurgia na criança: estado da arte. Experiência com 1408 procedimentos no Instituto da Criança "Pedro de Alcântara"

A videocirurgia em Cirurgia Pediátrica encontra um imenso campo de aplicações ainda, infelizmente, pouco explorado. São poucos os serviços que utilizam rotineiramente essa via de acesso e são escassas as referências nacionais publicadas. O Instituto da Criança do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo (ICr) há uma década e meia a utiliza e hoje a videocirurgia é a via de primeira escolha para tratar, entre outras doenças, o refluxo gastresofagiano, a colecistopatia calculosa, o testículo não palpável e o megaesôfago. Neste artigo relataremos a experiência em videocirurgia pediátrica do ICr, adquirida com 1408 pacientes operados, para divulgar e popularizar esta via de acesso, útil e benéfica para um grande número de situações e ainda subutilizada em Cirurgia Pediátrica.

FGF-23: estado da arte

Há aproximadamente 10 anos descobriuse um hormônio denominado FGF-23 (fator de crescimento de fibroblastos 23), um membro da família dos fatores de crescimento de fibroblastos, cujas funções atualmente conhecidas envolvem o metabolismo do fósforo (P) e a inibição da 1α hidroxilase, enzima responsável pela síntese de calcitriol. Tal descoberta possibilitou um novo entendimento sobre os mecanismos de controle do P, um elemento associado com mortalidade, especialmente na doença renal crônica (DRC). Nesta revisão descreveremos diversos aspectos deste hormônio, desde a sua descoberta, função, produção, mecanismo de ação, até os últimos estudos clínicos envolvendo o mesmo. Posteriormente, abordaremos as possíveis repercussões destes estudos na prática clínica.

Juegos olímpicos y paralímpicos en Brasil: aprendiendo de Barcelona y Sidney

Entre 2014 y 2016, Brasil será sede de numerosos eventos, donde se destaca la celebración de las Olimpiadas en Rio de Janeiro. La industria del turismo será una de las grandes beneficiadas, teniendo como objetivo duplicar el número de turistas, 10 millones en 2016, y generar oportunidades de negocios. Esta investigación plantea el análisis de dicha meta a través de dos elementos vinculados a las Olimpíadas, el legado y la apertura a nuevos segmentos de turistas, concretamente el turismo sénior y el accesible. Se llevará a cabo un análisis de contenido de la bibliografía existente sobre Río 2016 para determinar el estado del arte, y posteriormente se realizará un estudio de caso de las Olimpíadas de Barcelona y Sídney, con el objetivo de obtener las claves del éxito de su legado y la repercusión a nivel turístico. Esto posibilitará identificar los pasos a seguir por Brasil para alcanzar su objetivo turístico.