The synthesis, characterization, acute toxicity, antitumor activity, and histopathological analysis of a novel dinuclear platinum(2+) complex - [Pt(DACH-κ2N)µ-(C4H2O6-κ4O)Pt(DACH-κ2N)] - is reported. Through acute toxicity tests, it was possible to place the platinum complexes into categories according to the OECD protocol. The dinuclear complex was classified in category 2 (cisplatin - category 1; and oxaliplatin - category 2). Analyzing the interaction between dsDNA and dinuclear complex was observed an Tm increase, suggesting that the dinuclear complex-dsDNA interact probably through of the interstrand form. Evaluations of tumor masses extracted from mice inoculated with Ehrlich carcinoma demonstrated a percent of tumor inhibition similar for cisplatin and oxaliplatin, but statistically different and superior for the case of the dinuclear complex. Cisplatin and oxaliplatin showed 41.4 and 40.8% inhibition, respectively, while the dinuclear complex presented 66.3%. The histopathological analysis demonstrated that the group treated with cisplatin showed more significant tissue damage, moderate hepatic steatosis, and nephritis. The livers, spleens, and kidneys of the animals treated with the dinuclear complex were within the normality range with no tissue lesions, and absence of metastasis.

Disposal of plastics into the environment has been one of the major problems for the environment. The accumulation of polystyrene (PS) occurs in an accelerated way and, therefore, its reuse is challenging. Polystyrene nanocomposites impregnated with Ag nanoparticles (PS/AgNP) are generated from polystyrene residues and can be applied in the catalytic and plasmonic photo-catalytic reduction of phenolic compounds such as p-nitrophenol (PNP) to p-aminophenol (PAP). The AgNP were synthesized by a reverse micelle method resulting in nanoparticles with sizes in a range of 31.1-34.0 nm. The organocolloid was characterized by UV Vis and dynamic light scattering (DLS), demonstrating the preparation of spherical nanoparticles. The preparation of the PS/AgNP, obtained using a thermally induced phase separation method (TIPS), was confirmed by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), laser-induced breakdown spectroscopy (LIBS), and Fourier transform visible infrared spectroscopy (FTIR). Nanocomposites showed impressive performance in the catalytic and plasmonic photocatalytic reduction under blue light irradiation, reaching up to 98% conversion, being a promising material for wastewater treatment as well as other various environmental issues. We used blue light to observe the plasmonic effect of silver nanoparticles, and no previous reports of this composite for PNP reduction using blue light photocatalysis were found.

Human population growth and development has been largely dependent on non-renewable natural resources, which cannot be indefinitely sustained. Beyond, coal and other abundant resources cannot continue to be used at current rates due to their impact on the environment and climate. It is thus important to replace as much as possible the fossil fuels and scarce minerals as sources of energy and industrial raw materials. Biomass plays a key role in this scenario, since its availability depends on abundant but often misused resources: air, water, sunlight and land. The “oil shocks”, the recognition of impending resource shortages, the global pollution and climate change led many governments and organizations to create roadmaps to Bioeconomy. This includes the growing use of plants and animals to produce energy and raw materials, but it cannot create food scarcity. Agriculture depends on the plant macronutrients N, P and K, and this article discusses their role in plant and animal growth, production and consumption, dependence on non-renewable minerals and energy and perspectives for increasing their efficiency. Special attention is given to Brazilian agriculture that is heavily dependent on imported NPK, requiring strategic action and research.

Resumo O objetivo do presente estudo foi avaliar as propriedades antimicrobianas de uma nova formulação composta por nanopartículas de prata, denominada nano silver fluoride (NSF), na inibição de biofilme de Streptococcus mutans sobre a superfície do esmalte dentário de crianças. Variações no pH do biofilme dental e nos valores do índice de Higiene Oral Simplificada (IHO-S) também foram avaliadas após o tratamento com NSF. Trata-se de um estudo piloto, randomizado, duplo cego, cruzado e prospectivo. A amostra foi composta por 12 crianças, de ambos os gêneros, com idades entre 7 e 8 anos, as quais utilizaram as duas soluções testes, S1- NSF e S2- controle negativo (solução salina). O biofilme dental tratado com NSF apresentou menores valores de viabilidade de S. mutans (absorbância) e de unidades formadoras de colônias (UFC) do que o biofilme baseline e o biofilme tratado com S2. Houve diferença estatisticamente significativa entre os valores médios de IHO-S dos grupos baseline e S1, com uma redução dos valores. Não houve qualquer variação nos valores de pH do biofilme dental, antes e depois do tratamento com S1 e S2 e entre os diferentes grupos. Estas propriedades sugerem que NSF possui efeito bactericida sobre o biofilme de S. mutans, podendo ser utilizado clinicamente para o controle e prevenção da formação do biofilme dentário.

Abstract: The purpose of this study was to evaluate the antimicrobial properties of a new formulation containing silver nanoparticles, named Nano Silver Fluoride (NSF), to inhibit Streptococcus mutans biofilm formation on children’s dental enamel. The variations in dental biofilm pH and in the Simplified-Oral-Hygiene-Index (OHI-S) also were evaluated after the treatment with NSF. This was a randomized, double-blind, crossover and prospective pilot clinical trial study in which 12 schoolchildren, aged between 7-8 years, had their dental enamel treated with two solutions: S1 - Nano Silver Fluoride and S2 - negative control (saline solution), in different experimental moments. The dental biofilm adhered to enamel treated with NSF had lower values of S. mutans viability (absorbance) and colony forming units (CFU) than the S0 (baseline) and S2. There was a statistically significant difference between the OHI-S mean values of S0 and S1. There were no differences between the biofilm pH (both before and after the use of the test substances) and among the different groups. These properties suggest that NSF has bactericidal effect against S. mutans biofilm and it may be used for clinical control and prevention of dental biofilm formation.

No presente artigo são apresentados e discutidos, resultados obtidos pelo uso de quantum dots de semicondutores altamente luminescentes, obtidos por métodos de síntese coloidal. Os quantum dots apresentam superfície hidrofílica e pH fisiológico. Foram sintetizados em meio aquoso e funcionalizados com compostos orgânicos para utilização em diagnótico preciso de câncer de mama (carcinoma ductal infiltrante), câncer de cérebro (glioblastoma) e câncer cervical (colo de útero).

In this work we show and discuss the results obtained by using highly luminescent colloidal hydrophilic semiconductor Quantum Dots, synthesized in aqueous medium, physiological pH and functionalized with organic compounds for precise diagnostic of breast (ductal filling carcinoma), brain (glioblastoma) and cervical cancer.

Neste trabalho é apresentada a evolução estrutural de géis de polifosfato de alumínio, desde a associação das espécies que leva à gelatinização, e prosseguindo pelas etapas de envelhecimento e secagem. As alterações nas espécies formadoras da rede foram acompanhadas por RMN de 31P e 27Al, tanto em solução quanto no estado sólido. Verificou-se que as cadeias de polifosfato maiores é que dão a contribuição preponderante para a formação do gel e que as unidades de ortofosfato e os oligômeros menores são expulsos da rede durante a sinérese. Durante a formação e o envelhecimento dos géis ocorre hidrólise, que leva à quebra das cadeias e diminuição no seu tamanho médio. Amostras envelhecidas em ambientes com alta umidade relativa tendem a absorver água e isso contribui para que as reações de hidrólise ocorram de forma pronunciada, tornando-se líquidos viscosos. Por outro lado, as amostras expostas a umidades relativas da ordem de 20% tornam-se sólidos quebradiços em que as cadeias maiores tendem a se manter estáveis. Amostras secas a vácuo apresentam ainda aproximadamente 30% de água em sua estrutura.

The aim of this work was to investigate how the structure of aluminum polyphosphate gels change upon aging and drying. This is essential if one is interested in using a gel as a matrix to synthesize organic-inorganic hybrid materials. The liquid and solid samples were characterized by 27Al and 31P NMR spectroscopy. Larger polyphosphate chains make the main contribution to gel formation and the smaller units are expelled into the supernatant solution. Polyphosphate chains undergo hydrolysis and chain scission upon gelation. Samples aged in a moisture-rich environment turn into viscous liquids as a consequence of water uptake, followed by extensive hydrolysis. Samples exposed to low relative humidity environments dry yielding brittle samples in which larger chains are stable. Vacuum-dried samples still contain ca. 30%-weight water.

In this work we described theoretical calculations on the electronic structure and optical properties of the dyes crystal violet and malachite green based in semiempirical methods (Parametric Method 3 and Intermediate Neglect of Differential Overlap / Spectroscopic - Configuration Interaction) and the synthesis of a new hybrid material based upon the incorporation of these dyes in an aluminum polyphosphate gel network. The samples are nearly transparent, free-standing thick films. The optical properties of the entrapped dyes are sensitive to chemical changes within the matrix caused either by gel aging or external stimulli such as exposition to acidic and basic vapors that can percolate within the matrix. Our theoretical modeling is in good agreement with the experimental results for the dyes.

This review focus the more relevant foundations and applications of the Metallo-Organic Decomposition (MOD) technique, mainly within the last decade. The technique has grown significantly, mainly due to the good results concerning the preparation of multicomponent oxide systems with composition, structural and morphologic control, in a relatively simple way. This opened new opportunities to obtain materials with well-defined electrical and optical properties.

A eletrificação de sólidos é conhecida há quatro séculos, mas há muitas questões importantes sobre este assunto, ainda não respondidas: por exemplo, quais são as espécies portadoras de cargas em um polímero isolante eletrificado, como estas cargas estão espacialmente distribuídas e qual é a contribuição destas cargas para as propriedades do polímero? Técnicas microscópicas introduzidas recentemente são apropriadas para o mapeamento de potenciais elétricos ao longo de uma superfície sólida, portanto podem responder a uma destas questões, contribuindo para a resolução das outras. Este trabalho resenha resultados obtidos combinando-se as microscopias de varredura de potencial elétrico (SEPM) e de força elétrica (EFM) com a microscopia eletrônica analítica baseada na espectroscopia de perda de energia de elétrons (ESI-TEM). Os materiais examinados são colóides poliméricos (látexes), polímeros termoplásticos, nanopartículas e híbridos. Nos materiais particulados foram observados domínios com excesso de cargas elétricas, estendendo-se por dezenas e centenas de nanômetros, formados por grandes acúmulos de cátions ou ânions atingindo dimensões supramoleculares. No caso dos termoplásticos, a formação dos domínios elétricos ainda não está bem compreendida, sendo tentativamente atribuída a efeitos triboquímicos no processamento do plástico, à formação de domínios oxidados, à ação de radiação de alta energia no ambiente ou aos efeitos Mawell-Wagner-Sillars e Costa Ribeiro.

Electrostatic phenomena in insulators have been known for the past four centuries, but many related questions are still unanswered, for instance: which are the charge-bearing species in an electrified organic polymer, how are the charges spatially distributed and which is the contribution of the electrically charged domains to the overall polymer properties? New scanning probe microscopies were recently introduced, and these are suitable for the mapping of electric potentials across a solid sample thus providing some answers for the previous questions. In this work, we report results obtained with two of these techniques: scanning electric potential (SEPM) and electric force microscopy (EFM). These results were associated to images acquired by using analytical electron microscopy (energy-loss spectroscopy imaging in the transmission electron microscope, ESI-TEM) for colloid polymer samples. Together, they show domains with excess electric charges (and potentials) extending up to hundreds of nanometers and formed by large clusters of cations or anions, reaching supramolecular dimensions. Domains with excess electric charge were also observed in thermoplastics as well as in silica, polyphosphate and titanium oxide particles. In the case of thermoplastics, the origin of the charges is tentatively assigned to their tribochemistry, oxidation followed by segregation or the Mawell-Wagner-Sillars and Costa Ribeiro effects.