Synthesis of Gold Nanoparticles Using Amino Acids by Light Irradiation

The synthesis of nanoparticles is generally carried out by chemical reduction, which is effective but uses a number of toxic substances, making the process potentially harmful to the environment. Thus, as part of the search for environmentally friendly or green synthetic methods, this chapter aimed to present the synthesis of gold nanoparticles (AuNPs) using only HAuCl4, Milli-Q water, white light from a xenon lamp, and amino acids. A total of 21 amino acids were studied, and the shapes and sizes of the resultant nanoparticles were evaluated. The products were characterized by ultraviolet-visible (UV-Vis) and fluorescence spectroscopy, zeta potential measurements, and transmission electron microscopy. The synthesis of the AuNPs was successful with 18 amino acids, and the best results were obtained with aspartic acid, arginine, threonine, tryptophan, and valine. The nanoparticles were spherical and their sizes ranged from 5 to 100 nm. Changes in pH were required to improve the stability of the colloidal suspensions

O Desenvolvimento Econômico na Amazônia Legal: Seus Impactos Sociais, Ambientais e Climáticos e as Perspectivas para a Região

O DESENVOLVIMENTO ECONÔMICO NA AMAZÔNIA LEGAL: SEUS IMPACTOS SOCIAIS, AMBIENTAIS E CLIMÁTICOS E AS PERSPECTIVAS PARA A REGIÃO ECONOMIC DEVELOPMENT IN LEGAL AMAZON: ITS SOCIAL, ENVIRONMENTAL, AND CLIMATE IMPACTS AND THE PERSPECTIVES FOR THE REGION Marina Courrol Ramos RESUMO: O presente artigo tem por objetivo fazer uma análise dos impactos sociais, ambientais e climáticos decorrentes das várias tentativas de desenvolvimento econômico na Amazônia Legal e as perspectivas de desenvolvimento sustentável para a região a partir das políticas públicas ambientais existentes. Para tanto será feita uma análise histórica do desenvolvimento econômico da Amazônia, relacionando os ciclos econômicos com os fluxos migratórios, a questão fundiária e ambiental. Será dada ênfase à questão do desmatamento impulsionado a partir de 1970 decorrente das políticas de desenvolvimento econômico focadas em grandes obras de infraestrutura e assentamentos agrícolas, e sobre os efeitos sociais, ambientais e climáticos causados. Por fim serão analisadas as políticas públicas de combate ao desmatamento existentes e a utilização de mecanismos de incentivo como perspectiva para solucionar o problema. PALAVRAS-CHAVE: Amazônia; Desenvolvimento Econômico; Desmatamento; Direitos Sociais; Meio Ambiente; Mudanças Climáticas. ABSTRACT: This article aims to analyze the social, environmental, and climate impacts resulting of various attempts at economic development in the Legal Amazon and the perspectives of sustainable development for the region from the existing environmental public policies. In order to achieve this, a historical analysis of the economic development of the Amazon will be made, relating economic cycles with migration, and land and environmental issues. Emphasis will be given to the issue of deforestation driven since 1970 as a result of economic development policies focused on large infrastructure projects and agricultural settlements, and on the social, environmental, and climatic effects. Finally, public policies to combat deforestation and the use of incentive mechanisms will be analyzed as a perspective to solve the problem.KEYWORDS: Amazon; Economic Development; Deforestation; Social Rights; Environment; Climate Changes.SUMÁRIO: 1. As várias tentativas de desenvolvimento econômico na Amazônia legal. 2. A construção da rodovia transamazônica e o início do desmatamento. 3. Os efeitos ambientais e climáticos do desmatamento na Amazônia legal. 4. As políticas de combate ao desmatamento e as perspectivas de desenvolvimento econômico sustentável na região amazônica. Considerações finais. Referências

Hypocrellin B, a perylenequinonoid pigment, and its complexes with lanthanide ions: optical characterization and enhancements in its photodynamic properties

Hypocrellins, perylenequinonoid pigments isolated from Hypocrella bambusae, are known photodynamic agents. They exhibit several advantages over the other photosensitizers, such as ready preparation, easy purification, low aggregation tendency, high singlet oxygen generation quantum yield and rapid metabolism in vivo. However, hypocrellins do not exhibit absorption at wavelengths longer than 600 nm, which limits their application for PDT. To solve this problem our efforts were focused towards modifying the properties of hypocrellin B. in this study, hypocrellin B complexes formed with the lanthanide ions lanthanum (La(3+)), terbium (Tb(3+)) and europium (Eu(3+)), using ethanol as solvent, had their optical properties characterized through spectroscopic methods. We observed that all the lanthanide ions change the HB molecular structure, since displacements in the bands were noted in both absorption and emission spectra. Different molar ratios between the HB and the lanthanide ions were tested, and it was verified that the complexes with 1 mol of HB for 2 mol of lanthanide ions present the larger red-shift comparatively to pure HB. We also determined the dimerization constants for these complexes. Under excitation at 532 nm the singlet oxygen generation quantum yields were estimated by the emission at 1270 nm, where singlet oxygen has a well known emission peak. It can be affirmed that such complexations were responsible for an improvement in the optical properties of the HB molecule, which suggests that these complexes may find a good application at in vivo studies.IPEN CNEN SP, Ctr Laser & Aplicacoes, São Paulo, BrazilUniv Fed Sao Paulo, ICAQF, Departamento de Ciências Exatas e da Terra, Diadema, BrazilWeb of Scienc

Optical redox ratio and endogenous porphyrins in the detection of urinary bladder cancer:a patient based biopsy analysis

© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Bladder cancer is among the most common cancers in the UK and conventional detection techniques suffer from low sensitivity, low specificity, or both. Recent attempts to address the disparity have led to progress in the field of autofluorescence as a means to diagnose the disease with high efficiency, however there is still a lot not known about autofluorescence profiles in the disease. The multi-functional diagnostic system “LAKK-M” was used to assess autofluorescence profiles of healthy and cancerous bladder tissue to identify novel biomarkers of the disease. Statistically significant differences were observed in the optical redox ratio (a measure of tissue metabolic activity), the amplitude of endogenous porphyrins and the NADH/porphyrin ratio between tissue types. These findings could advance understanding of bladder cancer and aid in the development of new techniques for detection and surveillance. (Figure presented.)

Recent advances in lanthanide spectroscopy in Brazil

This review discusses recent advances in lanthanide spectroscopy involving luminescence applications Q2 carried out in Brazil. The revised topics include glasses, sol–gel, light-emitting diodes, nanoparticles, metal–organic frameworks, coordination polymers, thin films, energy transfer processes, upconversion and development of new theoretical tools. The important role played by Prof. Oscar L. Malta on this subject is evidenced by his many contributions to the broad range of investigations reported here and this review is dedicated to him, on the occasion of his 60th birthday

Políticas públicas de adaptação às mudanças climáticas em face das populações vulneráveis e da justiça climática

O aquecimento global é inquestionável, contudo os impactos resultantes das mudanças climáticas afetarão populações e lugares de forma desigual, já que populações que apresentam condições socioambientais desfavoráveis perceberão estes impactos de forma desproporcional. Neste contexto, a presente dissertação de mestrado teve por objetivo a análise das políticas públicas de adaptação em face das populações vulneráveis e da justiça climática no âmbito nacional. Partindo-se da análise de conceitos de adaptação, vulnerabilidade e impactos climáticos, identificou-se que no Brasil as populações pobres das zonas rurais do semiárido do Nordeste e as populações pobres das periferias dos centros urbanos, em razão das vulnerabilidades preexistentes, estão mais expostas aos riscos e impactos negativos das mudanças climáticas. Para estas populações, é dever do Estado garantir a realização dos direitos fundamentais por meio de políticas públicas de adaptação, principalmente preventivas, como forma de atenuar as desigualdades sociais, aumentando sua capacidade adaptativa e as tornando mais resilientes. Para tanto, foram analisadas políticas públicas relacionadas à questão climática em nível federal e estadual, verificando aquelas com potencial de promover adaptação destas populações vulneráveis e da justiça climática, a partir de uma abordagem de proteção aos direitos humanos e da dignidade humana. Conclui-se que apesar de haver no Brasil um regime jurídico climático que possibilite ações de adaptação, a preocupação com estratégias de adaptação no país ainda é muito recente. Como resultado disso, é evidente que o regime existente demonstra-se insatisfatório, com políticas que privilegiam mais ações de alívio do que a adaptação de longo prazo.Global warming is unquestionable, but the resulting impacts of climate change will affect people and places unevenly, since populations with unfavorable socio-environmental conditions experience these impacts disproportionately. In this context, this master thesis aims the analysis of adaptation public policies to vulnerable populations and climate justice at the national level. Starting from the analysis of the concepts of adaptation, vulnerability and climate impacts, we identified that in Brazil the poor people in rural areas of the Northeast semi-arid and poor people of urban peripheries, due to pre-existing vulnerabilities, are more exposed to risks and negative impacts of climate change. For these people, it is the State's duty to ensure the fundamental rights through public adaptation policies, especially preventive, in order to mitigate social inequalities, increase their adaptive capacity and become more resilient. Therefore, were analyzed public policies related to the climate issue at the federal and state level, checking those with potential to promote adaptation and climate justice for these people, through a human rights and human dignity protection approach. We conclude that although there is a climate legal regime in Brazil that enables adaptation actions, the concern about adaptation strategies is still very new. As a result, it is clear that the existing regime is unsatisfactory, with policies that privilege more relief actions than longterm adaptation actions

Production and characterization of the protease pappalysin from Leptospira interrogans

Espécies patogênicas de Leptospira são extremamente eficientes quanto à disseminação e propagação no hospedeiro, fato atribuído à capacidade que possuem de escapar da ação do sistema complemento, primeira linha de defesa da resposta imune inata, e também à capacidade de degradar componentes da matriz extracelular e do plasma humano. A secreção de proteases que inativam proteínas do hospedeiro é uma importante ferramenta utilizada por diversos microrganismos durante o processo de colonização. Os mecanismos subjacentes ao dano tecidual causado por leptospiras patogênicas ainda são pouco conhecidos. Assim como outras bactérias, leptospiras atravessam barreiras epiteliais e endoteliais para ter acesso aos órgãos. Adesão e degradação de componentes da matriz extracelular, principalmente da membrana basal, são certamente necessárias para invasão. Recentemente, nosso grupo avaliou a atividade proteolítica de proteínas secretadas por leptospiras, e uma análise do exoproteoma dessas bactérias permitiu a identificação de algumas proteases, dentre as quais a metaloprotease pappalysin-1 domain protein, à qual denominamos leptolisina. Neste projeto produzimos e caracterizamos funcionalmente a leptolisina de L. interrogans visando ampliar o conhecimento sobre essa metaloprotease de Leptospira nos processos de invasão e evasão imune. Análises in silico mostraram que esta protease pertence à categoria das short pappalysins, também encontradas em outras bactérias. A leptolisina está presente em todas as espécies de Leptospira analisadas, mas é mais conservada entre as espécies patogênicas do subclado P1. Uma caracterização bioquímica preliminar da atividade proteolítica desta protease foi realizada usando peptídeos FRET (Free Ressonance Energy Transfer). A enzima exibiu atividade máxima em pH 8,0 e 37oC, foi ativa na presença de diferentes sais e fortemente inibida por EDTA e 1,10-fenantrolina. Apresentou acentuada preferência por resíduos de arginina na posição P1. A ação proteolítica da leptolisina recombinante sobre moléculas do hospedeiro foi também avaliada in vitro e in vivo. A metaloprotease apresentou atividade sobre proteínas da matriz extracelular (proteoglicanas e fibronectina), moléculas da cascata de coagulação (fibrinogênio e trombina) e proteínas efetoras do sistema complemento humano (C2 a C9). Em um modelo de inoculação da proteína em pele dorsal de camundongos, observaram-se hemorragias e degradação de fibronectina extraída da pele. No que diz respeito aos impactos produzidos pela protease na coagulação, plasma humano tratado com doses elevadas da proteína deixou de coagular. Análises da microcirculação por microscopia intravital (modelo do músculo cremaster) apontaram um aumento no número de leucócitos rolantes na presença de leptolisina, e observou-se agregação leucocitária dependente de tempo. Uma cepa nocaute de leptolisina (&#916lic13434) foi produzida e caracterizada. Esta cepa apresentou menor sobrevivência em soro humano normal (SHN), comparada à cepa selvagem. No entanto, em um modelo de infecção epicutânea em hamsters, não se observou atenuação da virulência com a cepa nocaute, embora a carga bacteriana nos rins destes animais tenha sido inferior àquela observada nos animais inoculados com a cepa selvagem. Por fim, dados com soros de pacientes com leptospirose são sugestivos de que há produção de leptolisina durante infecções naturais por leptospiras patogênicas. A caracterização de toxinas, seus alvos e mecanismos de ação podem auxiliar no desenvolvimento de estratégias para combater a leptospirose.Pathogenic Leptospira species are extremely efficient in disseminating in the host, a fact attributed to their ability to escape complement system activation - the first line of defense of the innate immune response - and also to the ability to degrade extracellular matrix and other components of the human plasma. The secretion of proteases that inactivate host proteins is an important tool used by various microorganisms during the colonization process. The mechanisms underlying tissue damage caused by pathogenic leptospires are still poorly understood. Like other bacteria, leptospires cross epithelial and endothelial barriers to gain access to organs. Adhesion to and degradation of extracellular matrix components, especially the basement membrane, are certainly required for invasion. Recently, our group evaluated the proteolytic activity of secreted proteins by leptospires, and exoproteome analyzes of these bacteria allowed the identification of some proteases, including the metalloprotease pappalysin-1 domain protein, which we named leptolysin. In this work we produced and functionally characterized leptolysin from L. interrogans in order to expand our knowledge on this metalloprotease from Leptospira in the processes of invasion and immune evasion. According toin silico analyzes this protease belongs to the category of short pappalysins, also found in other bacteria. Leptolysin is present in all Leptospira species, but is more conserved among pathogenic species of the P1 subclade. A preliminary biochemical characterization of its proteolytic activity was performed using FRET (Free Resonance Energy Transfer) peptides. The enzyme exhibited maximum activity at pH 8.0 and 37oC, was active in the presence of different salts and was strongly inhibited by EDTA and 1,10-phenanthroline. It showed a marked preference for arginine residues in the P1 position. The proteolytic activity of recombinant leptolysin on host molecules was also evaluated in vitro and in vivo. The metalloprotease was active against extracellular matrix proteins (proteoglycans and fibronectin), coagulation cascade molecules (fibrinogen and thrombin) and effector proteins of the human complement system (C2 to C9). In mice dorsal skin leptolysin caused hemorrhages and degradation of skin fibronectin. With regard to the impacts produced by the protease on coagulation, human plasma treated with high doses of the protein failed to clot. Analyzes of the microcirculation by intravital microscopy (cremaster muscle model) showed an increase in the number of rolling leukocytes in the presence of leptolysin, and time-dependent leukocyte aggregation was observed. A leptolysin knockout strain (&#916lic13434) was produced and characterized. This strain showed lower survival in normal human serum (SHN) compared to the wild-type strain. However, in a model of epicutaneous infection in hamsters, no attenuation of virulence was observed with the knockout strain, although the bacterial load in the kidneys of these animals was lower than that observed in animals inoculated with the wild-type strain. Finally, data with sera from leptospirosis patients suggest that leptolysin is produced during natural infections by pathogenic leptospires. The characterization of toxins, their targets and mechanisms of action can help in the development of strategies to combat leptospirosis