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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.

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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.

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.