Assessing the Novel Mixed Tutton Salts K2Mn0.03Ni0.97(SO4)2(H2O)6 and K2Mn0.18Cu0.82(SO4)2(H2O)6 for Thermochemical Heat Storage Applications: An Experimental-Theoretical Study.

In this paper, novel mixed Tutton salts with the chemical formulas K2Mn0.03Ni0.97(SO4)2(H2O)6 and K2Mn0.18Cu0.82(SO4)2(H2O)6 were synthesized and studied as compounds for thermochemical heat storage potential. The crystallographic structures of single crystals were determined by X-ray diffraction. Additionally, a comprehensive computational study, based on density functional theory (DFT) calculations and Hirshfeld surface analysis, was performed to calculate structural, electronic, and thermodynamic properties of the coordination complexes [MII(H2O)6]2+ (MII = Mn, Ni, and Cu), as well as to investigate intermolecular interactions and voids in the framework. The axial compressions relative to octahedral coordination geometry observed in the crystal structures were correlated and elucidated using DFT investigations regarding Jahn-Teller effects arising from complexes with different spin multiplicities. The spatial distributions of the frontier molecular orbital and spin densities, as well as energy gaps, provided further insights into the stability of these complexes. Thermogravimetry, differential thermal analysis, and differential scanning calorimetry techniques were also applied to identify the thermal stability and physicochemical properties of the mixed crystals. Values of dehydration enthalpy and storage energy density per volume were also estimated. The two mixed sulfate hydrates reported here have low dehydration temperatures and high energy densities. Both have promising thermal properties for residential heat storage systems, superior to the Tutton salts previously reported.

New polymorphic phase of arachidic acid crystal: structure, intermolecular interactions, low-temperature stability and Raman spectroscopy combined with DFT calculations.

Saturated monocarboxylic fatty acids with long carbon chains are organic compounds widely used in several applied fields, such as energy production, thermal energy storage, antibactericidal, antimicrobial, among others. In this research, a new polymorphic phase of arachidic acid (AA) crystal was synthesized and its structural and vibrational properties were studied by single-crystal X-ray diffraction (XRD) and polarized Raman scattering. The new structure of AA was solved at two different temperature conditions (100 and 300 K). XRD analysis indicated that this polymorph belongs to the monoclinic space group P21/c (C2h5), with four molecules per unit cell (Z = 4). All molecules in the crystal lattice adopt a gauche configuration, exhibiting a R22(8) hydrogen bond pattern. Consequently, this new polymorphic phase, labeled as B form, is a polytype belonging to the monoclinic symmetry, i.e., Bm form. Complementarily, Hirshfeld's surfaces were employed to analyze the intermolecular interactions within the crystal lattice of this polymorph at temperatures of 100 and 300 K. Additionally, density functional theory (DFT) calculations were performed to assign all intramolecular vibration modes related to experimental Raman-active bands, which were properly calculated using a dimer model, considering a pair of AA molecules in the gauche configuration, according to the solved-crystal structure.

Framework for data-driven polymer characterization from infrared spectra.

Automating infrared spectra interpretation in microplastic identification is of interest since most current methodologies are conducted manually or semi-automatically, which requires substantial processing time and presents a higher accuracy limited to single-polymer materials. Furthermore, when it comes to multicomponent or weathered polymeric materials commonly found in aquatic environments, identification usually becomes considerably depreciated as peaks shift and new signals are frequently observed, representing a significant deviation from reference spectral signatures. Therefore, this study aimed to develop a reference modeling framework for polymer identification through infrared spectra processing, addressing the limitations above. The case study selected for model development was polypropylene (PP) identification, as it is the second most abundant material in microplastics. Therefore, the database comprises 579 spectra with 52.3% containing PP to some degree. Different pretreatment and model parameters were evaluated for a more robust investigation, totaling 308 models, including multilayer perceptron and long-short-term memory architectures. The best model presented a test accuracy of 94.8% within the cross-validation standard deviation interval. Overall, the results achieved in this study indicate an opportunity to investigate the identification of other polymers following the same framework.

Crystal growth, crystal structure determination, and computational studies of a new mixed (NH4)2Mn1-xZnx(SO4)2(H2O)6 Tutton salt.

Tutton salts have been extensively explored in recent decades due to their attractive physical and chemical properties, which make them potential candidates for thermochemical heat storage systems and optical technologies. In this paper, a series of new mixed Tutton salts with the chemical formula (NH4)2Mn1-xZnx(SO4)2(H2O)6 is reported. Crystals are successfully grown by the solvent slow evaporation method and characterized by powder X-ray diffraction (PXRD) with Rietveld refinement. In particular, the crystal structure of the mixed (NH4)2Mn0.5Zn0.5(SO4)2(H2O)6 crystal is solved through PRXD data using the DICVOL06 algorithm for diffraction pattern indexing and the Le Bail method for lattice parameter and spatial group determination. The structure is refined using the Rietveld method implemented in TOPAS® and reported in the Cambridge Structural Database file number 2104098. Moreover, a computational study using Hirshfeld surface and crystal void analyses is conducted to identify and quantify the intermolecular interactions in the crystal structure as well as to determine the amount of free space in the unit cell. Furthermore, 2D-fingerprint plots are generated to evaluate the main intermolecular contacts that stabilize the crystal lattice. Density functional theory is employed to calculate the structural, thermodynamic, and electronic properties of the coordination [Zn(H2O)6]2+ and [Mn(H2O)6]2+ complexes present in the salts. Molecular orbitals, bond lengths, and the Jahn-Teller effect are also discussed. The findings suggest that in Mn-Zn salts several properties dependent on the electronic structure can be tuned up by modifying the chemical composition.

Physicochemical properties calculated using DFT method and changes of 5-methyluridine hemihydrate crystals at high temperatures.

5-methyluridine hemihydrate (5 mU) single crystals were synthesized by the slow solvent evaporation method. The physicochemical properties, such as frontier molecular orbitals, global reactivity indices and vibrational were computationally studied through density functional theory (DFT). In addition, structural, vibrational, and thermal properties were obtained by powder X-ray diffraction (PXRD), Raman spectroscopy, thermogravimetric (TG) analysis and differential scanning calorimetry (DSC). PXRD evaluated the structural behavior of 5 mU crystal in the temperature range of 300-460 K. The high-temperature PXRD results suggested that the crystal undergoes two dehydration processes, being a first occurring from the orthorhombic structure (P21212) to triclinic (P1), in which the water losses occurred around 380 K. A second dehydration triggers the change from the triclinic structure to monoclinic (P21) within the 420-435 K temperature range. Furthermore, after this temperature, the anhydrous 5 mU suffers a melting process near 460 K, which is remarkably characterized as an irreversible process. Raman spectroscopy was carried out to identify the vibrational modes linked to the water molecule and the noticeable changes in these bands due to high-temperature effects around 380 K and 410 K. Indeed, changes on Raman bands, such as intensity inversion, the disappearance of bands associated with the hydrogen bonds formed from the water molecules and uracil group, and the ribose group were observed. Finally, this study provided details on the structural and vibrational changes caused by the dehydration of 5 mU crystals and the importance of hydrogen bonds for understanding the intermolecular interactions of the 5 mU, a methylated nucleoside with important biological functions.

Massive nasal bleeding and hemodynamic instability associated with clopidogrel.

A 58-year-old woman was brought to our emergency department with massive nasal bleeding and hemodynamic instability. The patient had been on clopidogrel treatment (75 mg/day) for 2 years, which was started after an episode of transitory ischemic attack. Blood pressure normalized following the administration of intravenous fluids, and the bleeding stopped after nasal tamponade and desmopressin therapy.

Síndrome de Down-análise clínica, citogenética e epidemiológica de 165 casos / Down Syndrome-A clinical, cytogenetic and epidemiologic analysis of 165 patients

Foram revisados 165 casos de crianças portadoras de Síndrome de Down(SD), acompanhados no Ambulatório de Genética Médica do Instituto Fernandes Figueira-Fundaçäo Oswaldo Cruz, segundo um protocolo clínico-laboratorial que englobava avaliaçäo clínica, análise citogenética, controle hematológico, dosagem de hormônios tireoidianos, ultrasonografia abdominal e RX de coluna cervical quando indicado. O diagnóstico clínico de SD foi estabelecido, na maioria dos casos, no primeiro ano de vida, sendo que 70 por cento dos pacientes encontrava-se abaixo de 4 anos de idade, com predomínio do sexo masculino. A trissomia livre do cromossomo 21 foi encontrada em 85 por cento dos exames citogenéticos realizados. A malformaçäo congênita mais comum foi cardiopatia (37,5 por cento) e, dentre as complicaçöes clínicas, observamos pneumonia de repetiçäo em cerca de 30 por cento dos casos, a maioria no primeiro ano de vida. Leucopenia foi observada em 14 pro cento dos pacientes, e a ultrasonografia abdominal permitiu a detecçäo precoce de litíase biliar em 4,3 por cento dos exames realizados, achado muito significativo na populaçäo pediátrica. Um programa clínico preventivo e prospectivo para detectar complicaçöes na SD mostrar-se-á eficaz no seu objetivo implicando, possivelmente, na reduçäo da mortalidade neste grupo de risco .

Non-ketotic hyperglycinemia- A typical case detected in a screening program for inborn errors of metabolism

Apresentamos um caso típico de hiperglicinemia näo-cetótica neonatal (McKusick 23830) detectado em um programa de triagem para erros inatos do metabolismo realizado no Rio de Janeiro e confirmado por análises que caracterizam os sintomas específicos desse distúrbio. Dados clínicos e características bioquímicas säo descritos e comparados com casos previamente relatados

Propylthiouracil and peripheral neuropathy

Os autores descrevem o caso de uma paciente de 38 anos de idade, com doença de Graves, que desenvolveu sinais e sintomas compatíveis a polineuropatia sensitivo-motora durante o tratamento com propiltiouracil. Após a retirada gradual da referida droga, o quadro neurológico desapareceu por completo. Sendo extremamente incomum o surgimento de neuropatia periférica secundária ao hipertiroidismo e em vista do uso corriqueiro do propiltiouracil no tratamento dessa enfermidade endócrina, os autores chamam a atençäo para a possível participaçäo do fármaco como agente etiológico de neuropatia periférica em enfêrmos usuários do propiltiouracil