Tropical Fruit Pulps: Processing, Product Standardization and Main Control Parameters for Quality Assurance

ABSTRACT Fruit pulp is the most basic food product obtained from fresh fruit processing. Fruit pulps can be cold stored for long periods of time, but they also can be used to fabricate juices, ice creams, sweets, jellies and yogurts. The exploitation of tropical fruits has leveraged the entire Brazilian fruit pulp sector due mainly to the high acceptance of their organoleptic properties and remarkable nutritional facts. However, several works published in the last decades have pointed out unfavorable conditions regarding the consumption of tropical fruit pulps. This negative scenario has been associated with unsatisfactory physico-chemical and microbiological parameters of fruits pulps as outcomes of little knowledge and improper management within the fruit pulp industry. There are protocols for delineating specific identity and quality standards (IQSs) and standardized good manufacturing practices (GMP) for fruit pulps, which also embrace standard operating procedures (SOPs) and hazard analysis and critical control points (HACCP), although this latter is not considered mandatory by the Brazilian legislation. Unfortunately, the lack of skilled labor, along with failures in complying established protocols have impaired quality of fruit pulps. It has been necessary to collect all information available with the aim to identify the most important hazards within fruit pulp processing lines. Standardizing methods and practices within the Brazilian fruit pulp industry would assurance high quality status to tropical fruit pulps and the commercial growth of this vegetal product towards international markets

Outer Sphere Urea Hydrolysis by Bis-Nickel Complexes: Questioning the Urea Activation by the Urease Enzyme

Urease enzyme has a dinuclear nickel active centre that hydrolyze urea into carbon dioxide and ammonia. In this work, two bis-nickel urease models were synthesized, [Ni2L(OAc)] and [Ni2L(Cl)(Et3N)2], based on the Trost bis-Pro0Phenol ligand (L). Interestingly, both complexes produced ammonia from urea, in which the [Ni2L(OAc)] complex was ten times slower than urease, whereas the more labile complex [Ni2L(Cl)(Et3N)2],was only four times slower. The intermediates were evaluated both experimentally and theoretically, indicating that the [Ni2L(H2O)2]+ intermediate is the most important to activate urea via an outersphere mechanism. Isocyanate was produced in a self-elimination mechanism. The reaction performed with different substrates indicated that the biomimetic complexes were able to hydrolyze isocyanate. The outersphere activation of urea by these complexes reals an alternative activation mechanism to be considered for the urease enzyme, not yet reported in the literature. . <br /

Urea Decomposition Mechanism by Dinuclear Nickel Complexes

Urease is an enzyme containing a dinuclear nickel active center responsible for the hydrolysis of urea into carbon dioxide and ammonia. Interestingly, inorganic models of urease are unable to mimic its mechanism despite their similarities to the enzyme active site. The reason behind the discrepancy in urea decomposition mechanisms between inorganic models and urease is still unknown. To evaluate this factor, we synthesized two bis-nickel complexes, [Ni2L(OAc)] (1) and [Ni2L(Cl)(Et3N)2] (2), based on the Trost bis-Pro-Phenol ligand (L) and encompassing different ligand labilities with coordination geometries similar to the active site of jack bean urease. Both mimetic complexes produced ammonia from urea, (1) and (2), were ten- and four-fold slower than urease, respectively. The presence and importance of several reaction intermediates were evaluated both experimentally and theoretically, indicating the aquo intermediate as a key intermediate, coordinating urea in an outer-sphere manner. Both complexes produced isocyanate, revealing an activated water molecule acting as a base. In addition, the reaction with different substrates indicated the biomimetic complexes were able to hydrolyze isocyanate. Thus, our results indicate that the formation of an outer-sphere complex in the urease analogues might be the reason urease performs a different mechanism

Urea Decomposition Mechanism by Dinuclear Nickel Complexes

Urease is an enzyme containing a dinuclear nickel active center responsible for the hydrolysis of urea into carbon dioxide and ammonia. Interestingly, inorganic models of urease are unable to mimic its mechanism despite their similarities to the enzyme active site. The reason behind the discrepancy in urea decomposition mechanisms between inorganic models and urease is still unknown. To evaluate this factor, we synthesized two bis-nickel complexes, [Ni2L(OAc)] (1) and [Ni2L(Cl)(Et3N)2] (2), based on the Trost bis-Pro-Phenol ligand (L) and encompassing different ligand labilities with coordination geometries similar to the active site of jack bean urease. Both mimetic complexes produced ammonia from urea, (1) and (2), were ten- and four-fold slower than urease, respectively. The presence and importance of several reaction intermediates were evaluated both experimentally and theoretically, indicating the aquo intermediate as a key intermediate, coordinating urea in an outer-sphere manner. Both complexes produced isocyanate, revealing an activated water molecule acting as a base. In addition, the reaction with different substrates indicated the biomimetic complexes were able to hydrolyze isocyanate. Thus, our results indicate that the formation of an outer-sphere complex in the urease analogues might be the reason urease performs a different mechanism

Avaliação neuropsicológica na esquizofrenia: revisão sistemática Neuropsychological evaluation in schizophrenia: a systematic review

O presente artigo tem como objetivo sintetizar estudos sobre os testes neuropsicológicos que estão sendo mais utilizados em esquizofrenia. Foi realizada uma revisão sistemática da literatura, consultando-se: PubMed, MEDLINE (via PubMed) e LILACS, no período entre 1995 e 2006. As palavras-chave foram: cognition and schizophrenia; evaluation and cognition and schizophrenia; functioning and cognition and schizophrenia. Foi feita uma pesquisa manual de referências dos artigos mais citados, incluindo estudos de metanálise, revisão teórica e da Measurement and Treatment Research to Improve Cognition in Schizophrenia. Critérios de inclusão: estudos com pacientes com esquizofrenia que mencionaram a utilização de testes neuropsicológicos. Foi feita uma revisão sobre os testes mais citados, para verificação de nomenclatura, indicações e quais estavam validados para o Brasil. Foram identificados 98 estudos: 77 empíricos, oito metanálises, seis revisões teóricas e sete da Measurement and Treatment Research to Improve Cognition in Schizophrenia. Foram encontrados 102 diferentes nomes de testes neuropsicológicos, com citação de 10 baterias de testes, na maioria compostas por subtestes já padronizados. Entre os 77 estudos empíricos, 22 (28,57%) foram sobre validação de instrumentos ou baterias de testes. Entre os 10 testes mais citados, apenas três possuem validação para o Brasil (WCST; Wechsler Adult Intelligence Scale; Mini-Mental Status Examination). Esses achados evidenciam uma ampla heterogeneidade nos critérios de seleção dos testes neuropsicológicos, divergências na nomenclatura e certa tendência para a criação de novos testes e baterias para avaliação de funções cognitivas. A relevância e características dos prejuízos cognitivos na esquizofrenia revelam a urgente necessidade de identificação específica e padronizada de métodos de avaliação neuropsicológica para pacientes brasileiros.<br>This article aims at summarizing studies on the most commonly used neuropsychological tests in schizophrenia. A systematic literature review was performed on PubMed, MEDLINE (via PubMed) and LILACS, from 1995 through 2006. The keywords were cognition and schizophrenia; evaluation and cognition and schizophrenia; functioning and cognition and schizophrenia. A manual research of references in most frequently cited articles was performed, including meta-analysis studies, theoretical reviews, and the Measurement and Treatment Research to Improve Cognition in Schizophrenia. Inclusion criteria were studies on schizophrenia patients that reported use of neuropsychological tests. A review of the most frequently cited tests was performed to check nomenclature, indications, and which were validated for Brazil. A total of 98 studies were identified: 77 empirical studies, eight meta-analyses, six theoretical reviews and seven from the Measurement and Treatment Research to Improve Cognition in Schizophrenia. There were 102 different names of neuropsychological tests; 10 batteries of tests were cited, most of them composed by previously standardized subtests. Of the 77 empirical studies, 22 (28.57%) were about validation of instruments or batteries of tests. Of the 10 most frequently cited tests, only three had been validated for Brazil (WCST; Wechsler Adult Intelligence Scale; Mini-Mental Status Examination). These findings show a wide heterogeneity in the selection criteria of neuropsychological tests, disagreement as to the nomenclature, and a certain trend toward creation of new tests and batteries for evaluating cognitive functions. The relevance and characteristics of cognitive impairments in schizophrenia confirm the urgent necessity of specific and standardized identification of neuropsychological evaluation methods for Brazilian patients