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In recent years, technological development in analytical instrumentation has progressed vigorously, which has allowed the evolution of analytical techniques that play an indispensable role within society, highlighting mass spectrometry. Parallel to the technological advance of this technique, the development of new ionization methods that are simpler, faster, and allow direct analysis without the need for prior treatment or sample processing is underway. The methods of ambient ionization derived from paper spray have been developing rapidly in current days, mainly in the forensic field, due to the chemical modifications made in the paper substrate and the introduction of new types of organic materials that function as a probe/substrate to collect, store, and ionize the sample, then enabling more efficient and selective analyzes. This review highlights direct analyzes by applying paper spray ionization in the forensic field and some variations of this technique, including Thread Spray Ionization (TSI) when a fabric thread is used; Touch Spray Ionization (TSI), which uses materials such as metallic needles, medical swabs, and wooden sticks; Fiber Spray Ionization (FSI), which applies polymeric fibers as substrates.

In the criminal sphere, it is extremely important to identify perpetrators of crimes based on latent fingerprints (invisible to the naked eye) revealed at crime scenes and their corresponding objects. The present work aimed to evaluate four synthetic analogues of curcumin as possible IDL developers, and to compare their results with those of carbon black developer, as well as to reach the most adequate parameters in the use of the LTQ and FT-ICR mass spectrometers with the paper spray ionization (PS) source to study the chemical composition of the endogenous substances contained in the IDL. For this, a 24-1 factorial design was developed, where it was verified that the distance and voltage factors were the most influential for the increase in the response of signals, in the analysis of latent fingerprints by PS. Among the detected substances we can mention around 20 fatty acids, and squalene. Finally, four potential developers, synthetic analogues of curcumin, were compared with carbon black developer. The revelation of latent fingerprints occurred efficiently, allowing the visualization of minutiae, such as bifurcation and end of line, making it possible to classify them, according to the Vucetich Fingerprint Classification System.

This paper discusses 286 proposals and reports of Green Chemistry (GC) teaching experiences, in papers of the Journal of Chemical Education (JCEd) until 2019. The analysis was based on previous categories: source-problem, paper focus, subjects/area of knowledge, target groups, GC contents, type of approach and purpose(s) of the proposal. A list of possible characteristics of each category served as an example to compare with the information resulting from the analyses, and thus improve the discussions. In 127 papers, GC and its teaching were associated, albeit generally, with the theme of sustainability/sustainable development, which points to its potential to face environment-related aspects of chemistry in teaching. A systemic vision in the interconnection between GC and sustainability/sustainable development appeared more explicitly in 39 papers up to 2019. So far, the analysis highlights a certain reproduction of traditional chemistry teaching, and little evidence of the particularities of GC teaching. Despite the intention of inserting GC into chemistry teaching, proposals for its incorporation are often made superficially, more as an addendum or an extra quality than a specific goal. More methodological detail of the experiments carried out is needed to help in the dissemination of GC in the training curriculum of chemists. The discussions and reports on teaching approaches based on Systems Thinking showed the opening of a promising new methodological challenge within this theoretical paradigm.

In this work, the peels of ripe banana (Musa sp.), variety “Prata”, were used to prepare a flour, which was evaluated for its physicochemical characteristics and antioxidant activity. The characterization of its chemical profile was performed by a fast and simple method: paper spray-mass spectrometry. This flour had high carbohydrate content and total dietary fiber, and significant amount of total phenolic compounds with antioxidant activity. In addition, this flour exhibited higher water-holding, oil-holding and swelling capacities than those of fruit by-products reported in the literature. Fourier-transform infrared spectroscopy confirmed the presence of functional groups of cellulose, hemicellulose, and lignin, constituents of insoluble dietary fiber. By the paper spray-mass spectrometry technique, it was possible to suggest the presence of 26 substances such as organic acids, phenolic acids, flavonoids, sugars, quinones, and terpenoids. Thus, this study demonstrated that the ripe banana peel flour has potential application as an ingredient for functional foods.

The main objective of the present work is represented by the characterization of the physical properties of industrial kraft paper (i.e. transversal and longitudinal tear resistance, transversal traction resistance, bursting or crack resistance, longitudinal and transversal compression resistance (SCT (Compressive Strength Tester) and compression resistance (RCT-Ring Crush Test)) by near infrared spectroscopy associated to partial least squares regression. Several multivariate models were developed, many of them with high prevision capacity. In general, low prevision errors were observed and regression coefficients that are comparable with those provided by conventional standard methodologies.

The contribution of the industrial activities to the environmental contamination phenomena is evident. Great efforts are dedicated to the establishment of methodologies which permits an adequate treatment of the produced effluents, as a manner of minimizing the environmental impact of these wastes. The methodologies based on photocatalytic processes are very promise alternatives, because permits degradation of a great number of chemical substances of high toxic potential, without the use of other chemicals. The present work is an overview about the principal environmental aspects related with the paper and cellulose industry and the main alternatives employed for the reduction of environmental impact produced for its residues. The principal results of the photocatalytic treatment of this kind of effluents using metallic semiconductors is also showed.

The presence of illicit drugs such as cocaine and marijuana in US paper currency is very well demonstrated. However, there is no published study describing the presence of cocaine and/or other illicit drugs in Brazilian paper currency. In this study, Brazilian banknotes were collected from nine cities, extracted and analyzed by capillary gas chromatography/mass spectrometry, in order to investigate the presence of cocaine. Bills were extracted with deionized water followed by ethyl acetate. Results showed that 93% of the bills presented cocaine in a concentration range of 2.38-275.10 µg/bill.

The incorporation of Cerrado fruits in food products such as ice cream has many advantages because it represents a source of nutrients and bioactive compounds. Given the demand for less laborious methods to analyze food, the paper spray ionization mass spectrometry technique was applied for the first time for a rapid characterization of the chemical components found cagaita ice cream. PS-MS in positive and negative ionization modes were used. The profile of volatile compounds was determined by headspace solid-phase microextraction combined with gas chromatography-mass spectrometry. Fingerprints obtained through PS-MS identified various classes of compounds, such as flavones, anthocyanins, sugars, organic acids, hydroxybenzoic acids, fatty acids, hydroxycinnamic acids, lignin, and phenylpropanoid. The use of both fibers enabled the extraction and identification of 18 volatile compounds in cagaita, and 16 of them were also identified in cagaita ice cream. The most common volatile compound found in both cagaita and ice cream was 3-carene monoterpene. Considering the effect of processing on cagaita constituents, 89% of the volatile compounds remained in the ice cream. Also, 78% of the fruit chemical compounds analyzed by PS-MS were found in the product. Thus, the results indicate that most of the fruit compounds remained in the ice cream after processing.

This work describes the fundamentals and evolution of two current solid-liquid separation methods found in the chemical laboratory: the filter paper and the centrifuge. Both methods were developed in the 19th century and are recognized as valuable techniques for industrial and laboratory purposes. However, significant improvements were introduced only from the end of the 19th century. The classical manual centrifuge was replaced by electric models: safety, maximum speed and number of samples that can be centrifuged at a time were greatly increased. The manufacture of filter paper was initially done by hand, but later benefited from papermaking industrial technologies. Many pretreatments of the wooden fibers were developed, particularly after 1880, thus resulting in many filter paper types for qualitative and quantitative applications. These two separation techniques are also found in various procedures in our everyday life.

Recycling of paper in industrial scale has become an established practice worldwide. In this work, organic compositions of three different kinds of sludge generated in recycle paper industry were studied, and the incorporation of one of those sludge in briket was also investigated. The characterization of organic compounds in sludge samples and briket was performed using Gas Chromatography coupled with Mass Spectrometry after a Soxhlet extraction. Different chemical classes were identified in each type of sludge, but just the sludge composed by cellulose residue did not presented polyaromatic hydrocarbons. Four formulations of sludge incorporated with charcoal for briket production were evaluated.

Laccase from Aspergillus sp was immobilized on glutaraldehyde-activated chitosan beads. A comparative study between free and immobilized laccase was conducted and the potential of the resulting immobilized derivative in the biodegradation of pulp and paper mill effluent was evaluated. The immobilized laccase is more resistant to various denaturing conditions, which allows for the reduction of 65% of the phenols (total and low molecular weight) and loss of 60% of total color in the effluent. These results show the potential of the immobilized laccase in the biodegradation of phenols, the chemical agents responsible for the high toxicity of the effluent generated in cellulose pulp industries.

A method for determining Cd, Cr, Cu, and Fe in biodiesel samples is proposed using energy dispersive X-ray fluorescence spectrometry (EDXRF) after extraction induced by emulsion breaking (EIEB). A volume of 7.0 mL of biodiesel and an aliquot of 500 µL of Triton X-100 solution (2%, v v-1) prepared in nitric acid were used to prepare the emulsion. After 5 min of manual agitation, phase separation was performed by centrifugation for 5 min at 2000 rpm. A 100 µL aliquot of the enriched aqueous phase was collected and applied to the center of a filter paper. After drying, the analysis was performed directly on the paper using EDXRF. The detection limits were 60, 20, 30, and 60 μg kg-1 for Cd, Cr, Cu, and Fe, respectively. Recovery tests were performed by adding 450 μg kg-1 of the analytes in biodiesel samples, and the results varied between 87 and 113%. The procedure was applied to biodiesel samples, and the concentrations obtained for the four analytes were compared with those obtained by inductively coupled plasma optical emission spectrometry (ICP OES) after sample digestion.

CHEMICAL ETHICS AND ITS TEACHING TO CHEMISTRY STUDENTS. This paper aims at broadening the understanding of scientific ethics by addressing chemical ethics, which deals with the benefits, risks and uncertainties associated with or arising from chemical activities. Chemical ethics is a theme of the Philosophy of Chemistry and its discussion has been recommended in Chemical Education. The purpose of its teaching is to recognize and analyze ethical problems, as well as to evaluate the possible paths that can be followed to make better decisions. In this paper, the implementation of a didactic intervention based on a historical case and on a hypothetical case in an undergraduate course is described. The aim of the intervention was to promote the development of ethical reasoning, instead of prescribing a specific ethical path, solution, or behavior. The historical case allowed students to understand the risks and uncertainties associated with the use of chemical substances. The hypothetical case made it possible to make ethical decisions by dealing with a problem situation, in which the characters’ possible decisions and their consequences were analyzed. Results show that the different approaches enable complementary understandings, which favor the development of students’ ethical reasoning.

ORGANOMETALLIC COMPOUNDS OF TIN(II) - SOME MAIN GROUP METAL STANNYLS. This paper aims to summarise some chemical information about selected main group metal stannyl compounds. The number of these compounds in the literature are much fewer than those with transition metal cations. Most papers report details of stannyls containing Li(I), Na(I) and K(I), such as synthetic routes, spectroscopic results and their molecular structures. This review comprises not only information of stannyls containing these cations, but also some alkaline-earth species containing Mg(II), Ca(II), Sr(II), Ba(II), as well as Sn(II). In some compounds, the alkaline or alkaline earth cation is connected to the stannyl fragment through a Sn – M bond, evidenced by X-ray crystallographic data or by solution- or solid-state 119Sn NMR experiments. The introduction part of the paper summarizes the chemical aspects of these compounds and their importance in the organometallic chemistry of Sn(II) as a research area. The second part of this review is dedicated to a broad discussion of the syntheses and structural aspects of some Li(I), Na(I) and K(I) derivatives. The structure of some stannyl compounds of Mg(II), Ca(II), Sr(II), Ba(II) are displayed in the third part of this paper. Two rare examples of Sn(II)-based stannyl derivatives are shown in the final part of the review. This review also highlights how important it is to correlate X-ray crystallographic data with those obtained by solution- or solid-state 119Sn-NMR experiments in order to determine the degree of covalence in the Sn – M bond.

Efavirenz, an antiretroviral drug, is a class 2 according to the biopharmaceutics classification system. Many dissolution enhancement systems have been tried and our group had success using wet milling to decrease particle size and granules were obtained by spray and freeze drying. In this paper we present data related to the upgrade in the process, raising the solids concentration in the suspension from 10 to 50% (m/v) and changing the drying step for a fluid bed granulation. After that, tablets were obtained. Granules and tablets were fully evaluated and a pharmacokinetic study was also performed with the granules. By powder X-ray diffraction (PXRD) and Fourier transform infrared spectroscopy (FTIR) it was possible to prove that there was no phase transition in the sample after milling and drying. Dissolution efficiency of 4 from 5 granules was higher than 90%, considering 83% for the raw material. Tablets were technically approved but the dissolution was impacted and just 2 out of 11 showed results > 80%. A high enhancement in the bioavailability was also observed, around 172%. So, it is possible to conclude that efavirenz microcrystals with enhanced dissolution and bioavailability can be formulated into tablets and are a viable system to develop a new drug product.

In the present article, the scientific journey that led to the development of the Nernst equation, a cornerstone in modern electrochemistry, is discussed. The paper not only explores historical achievements but also traces the evolution of scientific ideas and highlights the key figures who laid the conceptual and experimental groundwork for the seminal contributions of Nernst to the understanding of electrochemical systems. In this exploration, particular attention is paid to the examination of the first three articles published by Nernst between 1888 and 1889. These essential works marked the inception of the engagement of Nernst with the Leipzig Physical Chemistry circle, comprising the distinguished quartet: van’t Hoff, Arrhenius, Ostwald, and Nernst himself. Furthermore, the present study examines the intricate relationship between the Nernst equation and the four basic laws of Thermodynamics, all in an approach accessible to undergraduate students. A concise review elucidates the interpretation and significance of these foundational thermodynamic principles and explain how they hold the formulation of the Nernst equation.

Carbon dioxide and the related species bicarbonate and carbonate are known for centuries and are deeply involved with modern chemistry knowledge from the beginning. Carbonic acid, by its turn, was intuited more than a century before being synthesized for the first time, which was not obtained, however, without stumbles and mistakes. The equilibrium between HCO3− and CO32− in aqueous medium is free of disputes. However, the interconversion of the other three species is rather controversial. Several papers starting in the beginning of the 19th century until the present days are critically reviewed in order to understand the controversial history of the CO2/H2O system. Finally, experimental evidence and theoretical calculations allow us to place HCO3− as the central species as the conjugate acid for CO32− and conjugate base for two different acids: H2CO3 and CO2.

INFLUENCE OF THE PROCEDURE FOR GRANULOMETRIC SAMPLE ADJUSTMENT OF RED CERAMIC AGGREGATED WITH DIMENSION STONE WASTES FOR CLASSIFICATION ACCORDING TO THE ABNT CRITERIA’S. In order to clarify questions about the granulometric preparation of samples for the classification of solid wastes according to the Brazilian technical standard (NBR 10004/04), solubilization tests were carried out on red ceramic specimens made with conventional clay aggregated with ornamental rock residues. Samples were prepared by fragmentation and milling to verify the effects on metals releasing to the extractor medium. The specimens were made with 80% clay, 20% residue and 10% (m/m) moisture and sintered at 1000 °C. The data show that ceramics made with conventional clay, when discarded, will produce non inert wastes, as well as the ceramics made with dimension stone wastes added to the conventional raw material, according to the granulometry of its particles. After all, the metals concentration in the solubilization test are influenced by the sample granulometry. This paper shows that the method of granulometric adjustment should be detailed in the technical standard for solubilization tests (NBR 10006/04), in order to ensure the reliability of the method for classification of solid wastes.

Solid tumors are frequently affected by the presence of hypoxic cells, originating anomalous and disordered cell growth. This subpopulation presents resistance to conventional chemotherapy agents and radiotherapy, due to the difficulties of reaching the target region, the permanence in the G0 phase of cell cycle and the low local concentration of oxygen. The use of hypoxia activated prodrugs becomes, in this scenario, an effective and selective alternative in cancer therapy, though not yet available for clinical use in solid tumor treatment. Twenty years after the publication of the paper intitled “Agentes Antineoplásicos Biorredutíveis: Uma Nova Alternativa para o Tratamento de Tumores Sólidos” in the Química Nova journal (2002), the current essay aims to identify the advances in the pre-clinical and clinical studies regarding the development of new hypoxia-directed drugs and the improvement of the molecules previously studied. Moreover, to clarify the main challenges for the implementation and success of this drug class, in order to identify the hindrances for the preparation of a bioavailable, safe and selective drug.

The unique fundamental force related to chemical bonds, hydrogen bonds, and van der Waals interactions is the electromagnetic force, where the electrostatic force plays the major role. But, to our knowledge, no paper so far has explored the use of the electrostatic force explicitly to account for any molecular property (boiling point, solubility, etc.), except for the book Introductory Organic Chemistry and Hydrocarbons.1 This work uses the electrostatic force applied to chemistry to explain some molecular properties in organic chemistry. It also evaluates the understanding of Brazilian undergraduate students with respect to some topics of organic chemistry based on the electrostatic force. One questionnaire was applied to chemistry undergraduate students about Coulomb’s law and its application to organic chemistry, and the results indicate that most undergraduate students understand the electrostatic force equation applied to chemical education.

A COMMENTED TRANSLATION OF ACIDS AND BASES BY GILBERT NEWTON LEWIS. Gilbert Newton Lewis was a distinguished scientist in 20th century History of Chemistry. His work remains relevant for physical chemistry, organic chemistry and coordination chemistry nowadays. Lewis is well known by his propose for chemical bond, based on electron sharing. In 1923 he published two theoretical explanations for acids and bases: the former collaborating with Bronsted and Lowry and the later in his book Valence and the Structure of Atoms and Molecules (1923). In this book, the role of electron pairs in acid base reactions was highlighted decentering explanations from detachment/transfer of hydrogen ion. As a result, more substances could be classified as acids and bases. Also, in the context of organic and coordination chemistry new interpretations for reaction mechanisms showed up. The paper translated here, Acids and Bases (1938), makes a strong empirical description of acids and bases behavior. Lewis designed phenomenological criteria as speed of neutralization reactions, strength of the species acid-base titrations, and its applications as catalysts. In this manuscript, we carried out a commented translation of Lewis Acids and Bases published in 1938, considering it an inspiring source for research and educational applications for Portuguese speaking countries.

Reducing non-specific adsorption of proteins on the surface of magnetic nanoparticles (MNPs) is becoming increasingly important. In this paper, we proposed a novel surface modification procedure by grafting hyperbranched polyglycerol (HPG) onto the surface of MNPs (Fe3O4@SiO2@MAA), in which lots of hydroxyl groups from HPG not only provide the hydrates sheath to prevent non-specific adsorption of proteins, but also react with succinic anhydride to generate carboxyl groups that serve as active sites to specifically bind proteins. The protein adsorption experiments showed that the non-specific adsorption (0.07 μg mg-1) was reduced to 4.58% of that before modification. It also showed that the antigen binding capacity was 9.7 times higher than the original when detecting cardiac troponin I (cTnI) in human plasma samples, which indicated that the final synthesized MNPs had great application prospects in bio-separation and bioanalysis.

In this paper, theoretical and experimental research on blackbody thermal radiation is discussed and historically ordered. The main thermal radiation equations following Planck’s revolutionary idea are obtained using the formalism of statistical mechanics. These equations, already well known, are deduced in a very detailed and didactic way in order to facilitate the reader’s understanding. The consequent results of Planck’s formula for blackbody radiation are analyzed: the limits of the average energy for frequencies tending to zero and infinity, Stefan’s law and Wien’s displacement law.

Instrumental advances have been employed in the study of archeological remains such as prehistoric rupestrians paintings with the objective of chemically characterizing them in order to reconstruct the cultural technologies of a prehistoric human group and/or to support conservation science studies. The analytical techniques most commonly used in archaeometric research are non-destructive or semi-destructive and preferably portable to preserve the integrity of the rupestrians paintings. They include X-ray Fluorescence Spectrometry (XRF), Scanning Electron Microscopy coupled with Energy Dispersive Spectroscopy (SEM/EDS), Raman spectroscopy, X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Laser-induced Breakdown Spectroscopy (LIBS), and the many techniques with emerging applications such as Mössbauer Spectroscopy, X-ray Absorption Near Edge Structures (XANES), Particle Induced X-ray Emission Spectrometry (PIXE) and Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA ICP-MS). Therefore, this paper presents a review of the literature on the development of chemical strategies employed in the study of rock art, focusing mainly on the critical evaluation of analytical techniques used, limitations, challenges and the perspectives within this area of study.

The covalent bond is a classical topic in science education because it is fundamental to a considerable number of other concepts and by its ability to interpret several chemical phenomena. However, the process of learning this concept presents some difficulties discussed here. This article brings together the conceptions related to the covalent bond, identified, and reported from other studies, to find similarities and to organize what is known about the topic in epistemological themes. In this paper, it was conducted a systematic review using 3 databases, reaching more than 200 reports, and classified 253 sentences of misconceptions in 7 epistemological themes. The main contribution of this article is the classification of misconceptions into themes, which enables teachers and researchers to easily identify a topic considering its complexity. This review shows different misconceptions over the same topic, how misinterpretations can appear over all the models and theories related to the covalent bond, heterogeneity of school levels with the same misconception and mixing of theoretical foundations. Finally, we claim that the knowledge of this wide sight can be especially important to further lesson/unity planning, studies, and understanding of how to make a better transition between one topic to another.

Bleached eucalypt kraft pulps are widely used in print and writing (P&W) and tissue paper manufacture. Among the quality requirements of pulp for these papers, xylan content has been controversial. The objective of this study was to evaluate the influence of xylan content on bleachability, hygroscopic, physic-mechanical and optical properties of the pulp. In this study industrial unbleached eucalyptus kraft pulp (15.6% xylans) treated with different NaOH loads to change its xylan content was used. Subsequently, pulps were bleached by the ODHT(EP)D sequence to achieve 90% ISO of brightness, then refined and submitted to hygroscopic, physicomechanical and optical tests. NaOH treatments decreased the xylan content to 14.5-5.9% using NaOH loads of 10-70 g L-1. Pulp bleachability was not significantly affected by xylan content decrease. The decrease in xylan content negatively affected the water retention value and Klemm capillarity of the pulp, while water absorption capacity was positively affected. Tensile and tear index were negatively influenced by the reduction in xylan content, whereas bulk and light scattering coefficient increased.

Bicyclo[2.2.1]hepta-2,5-diene or norbornadiene (NBD) is a bicyclic hydrocarbon molecule used in many fields of chemistry since its first synthesis in 1950. NBD is the precursor of Aldrin, an agrochemical that was commonly used as an insecticide until the end of the XX century. Norbornadiene is capable of interconverting into its isomer, quadricyclane (QC), by the incidence of ultraviolet light. After that, the QC can release heat to return to the initial stage of NBD. To increase the energy efficiency and to enable the reaction to occur at the solar light, chemists have synthesized a wide variety of NBD derivatives. Papers in more than seventy years have studied and reported the physical and chemical properties of those compounds and their applications as rocket fuel, solar energy cell, homogeneous catalysis, and agrochemicals published between 1950 and 2021. Even computational chemistry has been used to investigate the NBD derivatives synthetic routes, elucidation, and application. In addition, this review describes other applications of norbornadiene.

The Lattes Platform, an information system maintained by the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), is the main source of information on Brazilian researchers. This paper presents a scientific output profile of the CNPq Productivity Research Fellows in the Chemistry area based on the information extracted automatically from Lattes curricula in the 2002-2011 period using the language "LattesMiner". This paper also provides a comparison with the results of Santos et al. (2010). The findings confirmed that the majority of the researchers are male (67.9%), classified as category 2 (63.2%) and working in the Southeast region (60.7%).

The aim of this paper was to present a simple and fast way of simulating Nuclear Magnetic Resonance signals using the Bloch equations. These phenomenological equations describe the classical behavior of macroscopic magnetization and are easily simulated using rotation matrices. Many NMR pulse sequences can be simulated with this formalism, allowing a quantitative description of the influence of many experimental parameters. Finally, the paper presents simulations of conventional sequences such as Single Pulse, Inversion Recovery, Spin Echo and CPMG.

An inert atmosphere is, in some cases, important for the performing of experiments where substances are toxic and/or sensitive to oxygen. However, the high cost and accessibility of an equipment to work under these conditions, results in the fact that most laboratories do not have this kind of equipment. In this paper, we present a simple and efficient project to build a cheap glove box for processes that require an inert atmosphere. The proposed glove box is made using medium density fiberboard (MDF), an acrylic lid, hinges, air valves, PVC gloves and other materials that can be found easily in local stores or on the internet. Tests to verify the quality of the nitrogen atmosphere were performed using the lighter test and niobium pentachloride (NbCl5), which is a moisture/ oxygen sensitive material. The results demonstrated that the equipment is able to maintain an inert atmosphere for several hours, does not permit lighter to function and maintains the NbCl5 stable.

Agathisflavone is a natural biflavone with restricted occurrence in plants. This biflavone presents several biological activities and can be important to developing new drugs. Obtaining such a molecule on a large scale for in vivo tests is a challenge. To date, there are no reports regarding its synthesis; thus, it is important to improve and develop methods for the purification of this bioactive compound from natural sources. Previous studies indicated that the leaves of Poincianella pyramidalis (Leguminosae) had agathisflavone predominantly. However, obtaining this compound requires some steps of chromatographic procedures and extraction with organic solvents. This paper compares four procedures for the purification of agathisflavone from its leaves, two by traditional chromatographic techniques and by complexation with inorganic bases. The purification in the automatic flash chromatography in two steps provides a high-yield extraction; the two procedures using alkaline extraction and the traditional method reduced to three steps provided the compound with similar yields. The biflavone was identified by TLC, and HPLC analysis showed that it was isolated with > 99% of purity. Thus, the applied methodologies provided the purification of this compound employing less volume of solvents, the number of chromatographic column procedures, and time-consuming, with increased yields.

Recently, graphene and modified graphene as one of the most suitable and the most important carbon nanomaterials have been introduced for drug delivery. In this paper, we have studied the binding characteristics of the EDC-NHS cross-linking process of graphene-phenyl-NH2 and 5-aminolevulinic acid (ALA) drug in both gas and solvent phases by density functional theory calculations. For describing binding properties and reaction nature between graphene-ghenyl-NH2 and ALA drug, quantum molecular descriptors, topological analysis, natural bond orbital analysis, analysis of the bond order, the density of states, and analysis bond length was investigated in solvent and gas phases. Due to the results, the complex of the graphene-phenyl-NH2 @ALA turns to absorb more electrons in water solvent than gas phase. Furthermore, the binding of graphene-phenyl-NH2 and ALA is mainly based on covalent interactions, and bond order of graphene-phenyl-NH2 @ALA complex is one in solvent and gas phases. The praphene-phenyl- NH2 @ALA complex has displayed a meaningful improvement of electronic and structural properties. Therefore, it represented that praphene-phenyl-NH2 being combined with the ALA drug is appropriate for use in drug delivery.

In an article recently published in Química Nova, entitled "Chemistry Without Borders" ("Química Sem Fronteiras") [Pinto, A. C.; Zucco, C.; Galembeck, F.; Andrade, J. B.; Vieira, P. C. Quim. Nova 2012, 35, 2092], the authors highlighted the important aspects of science and technology with special emphasis on the field of Chemistry and its contributions toward a more prosperous Brazil of future. As a second step in that direction, this article extends the discussion of a key issue for the country in the framework of the chemistry community through the so called position papers in strategic areas. This document is a part of the contribution of the Brazilian Chemical Society to the World Science Forum to be held in Rio de Janeiro in November 2013. In this context, the present paper provides a brief discussion on neglected tropical diseases (NTDs) with emphasis on the current challenges and opportunities towards the development and evolution of the field. NTDs leads to illness, long-term disability or death, and has severe social, economic and psychological consequences for millions of men, women, and children worldwide. In most cases, the available treatments are inadequate and extremely limited in terms of efficacy and safety, leading to an urgent demand for new drugs. In addition to the traditional challenges involved in any drug discovery process, it is widely recognized that there is an innovation gap and a lack of investment for research and development (R&D) in the area of NTDs. In the last few decades, methods toward combating, eradication, prevention, and treatment of NTDs have been repeatedly emphasized in the major international agendas. Developments in these strategies and alliances have continued to have an essential impact, particularly in the area of drug discovery, both in Brazil and globally and should be encouraged and supported. Several examples of international activities dedicated to the reduction of the devastating global impact of NTDs can be provided. Despite the beneficial developments in the past 30 years, NTDs continue to devastate poor communities in remote and vulnerable areas, in large part, due to market failures and public policies. Recent studies have shown that among 756 new drugs approved between 2000 and 2011, only four new chemical entities (NCEs) were identified for the treatment of malaria, while none were developed against NTDs or tuberculosis. Furthermore, only 1.4% of approximately 150,000 clinical trials were registered for neglected diseases, with a smaller number of trials for NCEs. Establishment and strengthening of global strategies involving the triad "government-academia-industry" is fundamental to the success in R&D of new drugs for NTDs. National and international public-private initiatives that aim to create, encourage, and invest in R&D projects have been implemented and therefore are of utmost importance to successfully integrate Brazil into this new paradigm. It is essential to lay the foundation for mechanisms that will intensify investments in infrastructure, training, and qualification of personnel with an ultimate strategic vision that foresees continuity. Our research group has made significant contributions to the development of this field with the goal of forging new frontiers while tackling both current and future challenges that include indispensable elements such as innovation and integration.

ABSTRACT The main aim of this paper was to contribute to reflections in Brazil on the need to transfer knowledge held at universities and R&D institutions over to companies, i.e. to transfer scientific knowledge of chemistry to technology. It discusses how the competitiveness of countries is increasingly dependent on their technological capacity. The chemicals industry is a fundamental driver of social, environmental, economic and industrial indicators of sustainable development. In Brazil, the chemicals industry's deficit has grown over the last three decades. Patents are important sources of information because patent documents contain 75% of all technological information available. The National Institute of Industrial Property in Brazil has created a Technology Observatory with the purpose of identifying and analyzing technological information contained in patent documents within the ambit of partnerships with government entities or business associations, in order to support their technology-related decision-making processes. The paper gives examples of ethanol and biotechnology patent documents, including pharmaceuticals, of which there are very few in Brazil. However, a few of the patent applications identified are filed in Brazil, giving the country the opportunity to transform this scientific knowledge into technology by means of partnership agreements with companies. Finally, the paper presents information on the patent applications filed by the world's leading chemicals companies as measured by their revenues, and the respective numbers of patent applications in the last five years in organic chemistry and polymers, sectors in which Brazil is currently dependent on imports for over 50% of its needs. The patent assignees in these sectors in Brazil are also identified, and the paper concludes that Brazil needs to invest in the development of professionals, providing clearly-defined career paths in technology innovation teams at R&D institutions, and to foster more initiatives such as the creation of a new research and innovation entity, EMBRAPII, since investing in science and technology is a prerequisite for knowledge production, industrial property, economic development and, consequently, the competitiveness of the country.

A hundred years ago, a twenty-eight year old Danish scientist published a series of three papers in which electron motion was quantized. The Bohr atomic model is surely known by every chemistry student. Nevertheless in this same 1913 trilogy, Bohr studied atoms with several electrons as well as molecules. Chemistry students, in general, are not aware of the Bohr molecule. The present paper aims at rescuing this important classical model. A review of the Bohr atomic model for both one and several electrons is discussed, together with a theoretical presentation of the Bohr molecule.

In this paper we built three co-authorship networks displaying the acquaintances between countries, universities and authors that have published papers in Quimica Nova from 1995 to 2008. Our research was conducted applying a bibliometric approach to 1782 papers and over 4200 authors. Centrality measures were used and the most significant actors of each network were pointed out. The results using the centrality metrics and the network structures indicated that Quimica Nova resembles a typical scientific community.

This paper presents a historical of the Biosilicate®, a bioactive glass-ceramic developed at the Vitreous Materials Laboratory of the Federal University of São Carlos, Brazil. After decades of study accomplished with bioactive glasses and glass-ceramics, Biosilicate® results from a natural evolution and has similar bioactivity index, but far superior mechanical properties than of all bioactive glasses. Biosilicate® is almost fully crystalline and also exhibits much higher bioactivity than all the currently commercially available bioactive glass-ceramics. Due to its special characteristics, Biosilicate® has been successfully tested for several medical and dental applications as we thoroughly discuss in this review paper.

The year 2011 has been chosen as the International Year of Chemistry and it will focus on the importance of sustainability in the field of chemistry. The program "Alternative Synthetic Routes for the Prevention of Pollution", implemented 20 years ago in the USA marked the official start of Green Chemistry. Currently, many lines of research in chemistry observe and comply with the concepts of green chemistry contributing significantly to the advancement of science. Hence, the objective of this paper is to present an overview of published papers on Green Chemistry in national and international journals from the "CAPES Portal Database", from 1997 to May 2010.

This paper presents a technology roadmap applied to renewable raw materials as a basis for public policy and strategies in Brazil. The roadmap, developed by Braskem professionals and academic experts, intends to be a basis of discussion and common language creation regarding the possible utilization of renewable raw materials for biofuel and chemical production in Brazil. Following this perspective, the roadmap is presented to public debate and contribution from the stakeholders. The paper describes the roadmap construction and presents the main implications for policy and strategy goals. An analysis of the innovation dynamics in renewable raw materials is developed as an outcome of the roadmap.

In this paper it is presented a thermodynamic analysis that aims to find the mathematical expression of the variation of extent of reaction with the infinitesimal variation in the temperature at constant volume of a chemical equilibrium mixture. The goal of this paper is to establish an alternative approach to avoid both the Le Chatelier's principle and the problems that emerge when trying to apply its qualitative statements. This attempt is based on the laws of thermodynamics.

Global environmental issues have gained strength since the 1960 decade and the relationship between the chemical industry and the environment has become increasingly tight since then. In this sense, environmental management has gained more space making organizations think strategically about their business and the possible impacts that they can promote on the environment. The present paper shows two brief timelines: the history of the chemical industry and the important events for environmental issues. In addition, it reports an investigation into the insertion of the discipline of environmental management in curricular matrices of institutions in Paraná and didactic experiments carried out at the State University of Ponta Grossa: simulation of environmental audit and analysis of the environmental management of the chemistry teaching laboratories of that institution a from the survey of environmental aspects and impacts and the elaboration of the environmental risk index. Finally, a questionnaire is shown with the graduates who took the discipline and how they perceive the importance of it in professional life. The reflection on social and environmental responsibility is extremely important for sustainable development and the chemist has a leading role in this path.

This paper is focused on a review of the design features and the electrochemistry characterization of anode-supported planar SOFC. Studies and results of metallic alloy interconnectors and recovery for protection against corrosion and for contact layer are showed. Moreover a discussion of examples of measurements of impedance spectrometry, according to the literature and our experimental results are made. For the anode supported fuel cells the power density varies from 0.1 to 0.5 Wcm², according to results in the literature (showed in this paper). For electrolyte supported fuel cell the power density can be 10 Wcm-2 for high temperatures. An English-Portuguese glossary of most used terms in SOFC stack is given for greater clarity and to introduce new terms to the reader.

This paper reports an analytical method for the determination of ambroxol in micellar medium by spot test-diffuse reflectance spectroscopy. The reflectance measurements were performed analyzing the colored compound (λ= 520 nm) produced from the reaction between ambroxol and p-dimethylaminocinnamaldehyde on the surface filter paper. The linear range was from 1.21 × 10"3 to 9.65 × 10"3 mol L-1 (500 - 4000 μg mL-1). The limit of detection and quantification were 3.50 x 10-4 mol L-1 (145 μg mL-1) and 1.16 x 10-3 mol L-1 (481 μg mL-1), respectively. Five commercial samples were analysed and the results obtained by the proposed method were in good agreement with those obtained by the literature method at 95% confidence level.

The Brazilian Chemical Society - SBQ has made substantial contributions to the formation of qualified human resources at all levels since its foundation in 1977. Several papers addressing this subject have been published in Quimica Nova by different authors over the last years. In this paper, we discuss the present need for "Curriculum Guidelines" for undergraduate education in Chemistry with actions to be taken in accord with the Principles of Green Chemistry and Sustainability.

Basic concepts that play an important role in some organic reactions are revisited in this paper, which reports a pedagogical experience involving undergraduate and graduate students. A systematic procedure has been applied in order to use widespread available computational tools. This paper aims to discuss the use of computers in teaching electrophilic addition reactions to alkenes. Two classical examples have been investigated: addition to non-conjugated alkenes and addition to conjugated dienes. The results were compared with those normally discussed in organic textbooks. Several important concepts, such as conformational analysis and energy control (kinetic and thermodynamic) involved in reaction mechanisms can be taught more efficiently if one connects theoretical and practical tools.

This paper discusses the Brazilian academic production on Chemical Education. The main source of information is the annual meeting of the Brazilian Chemical Society (RASBQ) covering the period 1999-2006. All the papers presented by the Division of Chemical Education of the RASBQ were reviewed to permit a discussion about the development of the area in Brazil. This bibliographical revision comprises the following aspects: year of presentation, Brazilian region and institution of production, scholastic level encompassed by the study, the kind of academic work (or research type) and thematic focus of the study.

Poor standards in schools and the increase in the number of institutions of higher education - frequently without the due control - have adversely affected the quality of university level education in Brazil. On the other hand, evaluation of undergraduate courses, which has been carried out regularly since the min 1990's allow, within certain limits, a description of the quality Brazilian higher education courses in general, and Chemistry courses in specific. This paper evaluates the results of the national examinations (2000 and 2003's ENC, and 2005's ENADE), attrition rates for the 1990's and for the 2000-2005 period, as well as the perceptions of students and instructors that took part in those exams. Furthermore, the paper also analyzes the opinions of academics and of private sector professionals about the educational system's capacity to meet the job market's demand for skilled labor force. The actual profile of Chemistry graduates is then compared to what is demanded from them by the market, revealing deficiencies in the educational system. The expected essential curricula changes that would introduce an innovative and advanced approach in the undergraduate courses have become great challenges. In this sense, the paper seeks to reflect on questions such as: How to give informative courses a formative emphasis? Which programs should be included in the curricula to involve students in activities that require initiative and decision-making, thus fostering both learning and interest in Chemistry? How to prepare instructors for schools and for higher education? How to increase instruction in related areas without expanding the curricula excessively? How to introduce entrepreneurship in the curricula and further awareness of the professional non-academic careers in the area?

This paper shows different aspects related to the application of different thermal analysis techniques in the study of energetic materials. The criteria used to choose the best technique and an exact approach to adjust the experimental data with a proper model are here discussed. The paper shows how to use the different thermal analysis results to help develop new compounds, to study the stability of some energetic materials and their compatibility, and the conditions necessary for a secure storing environment.

In this work commercial filters papers were organomodified with tetraethylorthosilicate (TEOS) and 3-aminopropyltriethoxysilane (3-APTS), aiming at the development of a new analytical procedure for in-situ speciation of labile and inert metal species in aquatic systems. Parameters that exert influence on the metal lability such as pH, chelating time, concentration and characteristics of the organic matter were studied in the laboratory using tests for metal recuperation. The results showed slower kinetics for Cu ion than for Ni, Mn and Cd in the absence of aquatic humic substances (AHS). The relative lability observed for complexed metals in aquatic humic substances using organomodified filter papers was Cu>>Cd>Ni>Mn. The pH values, structural characteristics and concentration of AHS exert strong influence on the lability of the metals. The results obtained showed that the utilization of organomodified filter papers can be an interesting and promising alternative for in situ characterization of metal lability in aquatic systems.

Nanomaterials make up an emerging area in Chemistry and in the science of materials. This area constitutes the development of methods for synthesizing nanoscopic particles of a given material used for scientific investigation. Nanomaterials have a wide range of commercial possibilities and technological applications, including their use in analytical chemistry, as well as in electronics, optics, engineering, medicine, devices for liberation of drugs, bioencapsulation, among others. This paper presents a summary about nanoelectrodes, devices built from nanoparticles, which show great potential as electrochemical tools in many different types of analysis. The purpose of this paper is to review the construction methodologies of nanoelectrodes, and to point out their successful applicability in the various fields of immune assays and other analytical procedures with quantitative purposes.