RESUMO

Maleic acid was studied by Raman spectroscopy and powder synchrotron X-ray diffraction (XRD) under high pressure conditions by using a diamond anvil cell. The Raman spectroscopy measurements were performed from ambient pressure up to 9.2 GPa in the 100-3200 cm-1 spectral range. While the XRD measurements were performed up to 10.1 GPa. Here we present the pressure-dependence behavior from both the Raman modes and cell parameters. Maleic acid lattice parameters decrease anisotropically as a function of pressure and a reduction of 27% in the volume of the unit cell was observed. Modifications in the material's compressibility were observed at around 2 and 6 GPa.

RESUMO

L-histidinium hydrogen oxalate (L-HisH)(HC2O4) crystal is formed from amino acid. L-histidine with oxalic acid whose vibrational high pressures behavior have not yet been investigated in the literature. Here we synthesized (L-HisH)(HC2O4) crystal by slow solvent evaporation method in a 1:1 ratio of L-histidine and oxalic acid. In addition, a vibrational study of (L-HisH)(HC2O4) crystal as a function of pressure was performed via Raman spectroscopy in the pressure range of 0.0-7.3 GPa. From analysis of the behavior of the bands within 1.5-2.8 GPa, characterized by the disappearance of lattice modes, the occurrence of a conformational phase transition was noted. A second phase transition, now from structural type, close to 5.1 GPa was observed due to the incidence of considerable changes in lattice and internal modes, mainly in vibrational modes related to imidazole ring motions.

RESUMO

Crystals of dipeptide α-L-aspartyl-L-alanine (α-Asp-Ala), C7H12N2O5, were studied under high-temperature conditions through vibrational spectroscopy (IR and Raman) and thermal analysis (Differential Scanning Calorimetry - DSC). From the analysis of the results, it is possible to conclude that: (i) the studied material undergoes a reversible order-disorder phase transition at 373 K on heating, where several changes were observed in the vibrational spectra, especially with vibrational modes of the units that participate directly of the hydrogen bonds; (ii) the phase transition undergone by the α-Asp-Ala crystal (about 373 K) involves changes in hydrogen bonds, possibly the rupture of at least one of them, and change in the conformation of the molecules in the unit cell.

RESUMO

In this work, we present a temperature-dependent behavior of monoclinic silver dimolybdate (m-Ag2Mo2O7) microrods using in situ Raman scattering. The m-Ag2Mo2O7 microrods were obtained by the conventional hydrothermal method at 423 K for 24 h. The structural and morphological characterization of the sample has been done by powder X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. Temperature-dependent Raman scattering measurements were performed on m-Ag2Mo2O7 microrods, and the results show an irreversible first-order structural phase transition at 698 K-723 K and the melting process at 773 K. Changes in the Raman spectra confirm the phase transition from the P21/c monoclinic structure to the P-1 triclinic structure. No morphological changes were observed during the structural phase transition of the sample at 723 K. Time-dependent optical microscopy at 773 K showed the growth of nanowires on the Ag2Mo2O7 microrods in the triclinic structure.

RESUMO

Lung cancer patients with COVID-19 present an increased risk of developing severe disease and, consequently, have poor outcomes. Determining SARS-CoV-2-host interactome in lung cancer cells and tissues, infected or uninfected with SARS-CoV-2, may reveal molecular mechanisms associated with COVID-19 development and severity in lung cancer patients. Here, we integrated transcriptome data of lung tumors from patients with small- or non-small cell lung cancer (SCLC and NSCLC) and normal lung and lung cancer cells infected with SARS-CoV-2. We aimed to characterize molecular mechanisms potentially associated with COVID-19 development and severity in lung cancer patients and to predict the SARS-CoV-2-host cell interactome. We found that the gene expression profiles of lung cell lines infected with SARS-CoV-2 resemble more primary lung tumors than non-malignant lung tissues. In addition, the transcriptomic-based interactome analysis of SCLC and NSCLC revealed increased expression of cancer genes BRCA1 and CENPF, whose proteins are known or predicted to interact with the SARS-CoV-2 spike glycoprotein and helicase, respectively. We also found that TRIB3, a gene coding a putative host-SARS-CoV-2 interacting protein associated with COVID-19 infection, is co-expressed with the up-regulated genes MTHFD2, ADM2, and GPT2 in all tested conditions. Our analysis identified biological processes such as amino acid metabolism and angiogenesis and 22 host mediators of SARS-CoV-2 infection and replication that may contribute to the development and severity of COVID-19 in lung cancers.

Assuntos

COVID-19 , Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Transcriptoma , Humanos , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/patologia , COVID-19/genética , COVID-19/patologia , Pulmão/metabolismo , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , SARS-CoV-2

RESUMO

The multicomponent glycinium maleate single crystal was grown by the slow evaporation method. The crystal was submitted to pressures ranging from 1 atm to 5.6 GPa and Raman spectroscopy was used as a spectroscopic probe. The modifications of relative intensity bands related to the lattice modes at 0.3 GPa were associated with rearrangements of hydrogen bonds. Moreover, between 1.7 and 4.8 GPa the Raman results indicate that the crystal experience a long structural phase transition, which was confirmed by PCA analysis. DFT calculations gave us more precision in the assignments of modes. The behavior of the internal modes under pressure showed that the maleic acid molecule undergoes greater modifications than glycine amino acid. All observed modifications were reversible when the pressure was released.

Assuntos

Maleatos , Análise Espectral Raman , Ligação de Hidrogênio , Transição de Fase

RESUMO

Background Carbapenem-resistant Pseudomonas aeruginosa (CRPA) infection after kidney transplantation (KT) is associated with high mortality. Methods We analysed an outbreak of infection/colonization with IMP-1-producing CRPA on a KT ward, conducting a case-control study. Cases were identified through routine surveillance culture and real-time polymerase chain reaction (PCR) for carbapenemase performed directly from rectal swab samples. Controls were randomly selected from patients hospitalized on the same ward during the same period, at a ratio of 3:1. Strain clonality was analysed through pulsed-field gel electrophoresis (PFGE), and whole-genome sequencing was performed for additional strain characterization. Results CRPA was identified in 37 patients, in 51.4% through surveillance cultures and in 49.6% through clinical cultures. The median persistence of culture positivity was 42.5 days. Thirteen patients (35.1%) presented a total of 15 infections, of which 7 (46.7%) were in the urinary tract, among those, 30-day mortality rate was 46.2%. PFGE analysis showed that all of the strains shared the same pulsotype. Multilocus sequence typing analysis identified the sequence type as ST446. Risk factors for CRPA acquisition were hospital stay > 10 days, re-transplantation, urological surgical re-intervention after KT, use of carbapenem or ciprofloxacin in the last three months and low median lymphocyte count in the last three months. Conclusions KT recipients remain colonised by CRPA for long periods and could be a source of nosocomial outbreaks. In addition, a high proportion of such patients develop infection. During an outbreak, urine culture should be added to the screening protocol for KT recipients.

Assuntos

Ciprofloxacina , Mortalidade , Cultura , Reação em Cadeia da Polimerase em Tempo Real

RESUMO

Raman spectra of Fe-doped L-asparagine monohydrate (LAM:Fe) crystal were studied under several temperatures varying from 17 to 490 K. The effect of Fe (III) ion on the stability of the crystal in changing temperature through the vibrational spectra was discussed. The behavior of inter and intra-molecular vibration modes has indicated two phase transitions and an amorphous transformation. These effects were also clarified by X-ray powder diffraction measurements which corroborate very well the Raman data. In addition, we have determinated the lattice parameters of all phases and verified that under low temperature conditions the crystal undergoes a conformational transition whereas under high temperatures its structure transforms from the orthorhombic (P212121-space group) to the monoclinic (P21-space group) symmetry and, after this process, it goes to an amorphous phase due to the start of the decomposition. Finally, differential scanning calorimetry analysis was utilized as complementary technique to investigate the structural stability of LAM:Fe and results are in a good agreement with the Raman and the X-ray diffraction data.

RESUMO

DL-glutamic acid monohydrate crystal was synthesized from an aqueous solution by slow evaporation technique. The crystal was submitted to high-pressure (1 atm-14.3 GPa) to investigate its vibrational behavior and the occurrence of phase transitions. We performed Raman spectroscopy as probe and through the analysis of the spectra we discovered three structural phase transitions. The first one occurs around 0.9 GPa. In this phase transition, glutamic acid molecules suffer modifications in their conformations while water molecules are less affected. The second phase transition at 4.8 GPa involves conformational changes related to CO2-, NH3+ units and the water molecules, while the third one, between 10.9 and 12.4 GPa, involves motions of several parts of the glutamic acid as well as the water molecules. Considering the dynamic of high pressure, the second phase of DL-glutamic acid monohydrate crystal presented a better stability compared with the second phase of its polymorphs α and ß L-glutamic acid. In addition, water molecules seem to play important role on this structural stability. All changes are reversible.

Assuntos

Ácido Glutâmico/química , Conformação Molecular , Transição de Fase , Pressão , Cristalografia por Raios X , Ligação de Hidrogênio , Modelos Moleculares , Análise Espectral Raman

RESUMO

BACKGROUND: Alopecia areata (AA) is a complex immune and polygenic inflammatory disease that causes hair loss on some or all areas of the body; extent, severity and progression vary widely among individuals. Alopecia areata, considered one of the most frequently occurring immune diseases, affects 0.2% of the world population at any given time. Uncertainty prevails about the most appropriate intervention for AA. The aim is to evaluate the effectiveness and safety of over 80 interventions for AA, including minoxidil - one of the most promising interventions for patchy AA in children and adults of both sexes. MATERIAL AND METHODS: An extensive search was conducted of international medical literature involving randomized clinical trials (RCTs) of AA interventions. RCTs were evaluated qualitatively and quantitatively according to the previously published protocol and for seven specific outcomes. RESULTS: The meta-analysis involving 5% minoxidil vs. placebo presented a significant difference in favor of 5% minoxidil with the moderate quality of evidence in children and adults with patchy AA (RR 8.37 [3.16-22.14], 95% CI). No severe adverse event was reported. CONCLUSIONS: Treatment of patchy AA with 5% minoxidil proved effective, and clinically and statistically safe in studies with limited sample size; quality of evidence was moderate. Further studies with sound methodological quality, more participants and outcome observations lasting longer than 6 months are needed to address remaining uncertainties.

Assuntos

Alopecia em Áreas/tratamento farmacológico , Minoxidil/uso terapêutico , Vasodilatadores/uso terapêutico , Humanos , Ensaios Clínicos Controlados Aleatórios como Assunto

RESUMO

DL­isoleucine single crystals were grown by the slow evaporation method at ambient temperature. Their vibrational properties were studied at ambient temperature as a function of pressure by Raman scattering. At ambient conditions the mode assignment was done in terms of the Potential Energy Distribution (PED) through density functional theory calculations. Both nitrogen and neon were used as pressure transmitting media. The pressure-dependent investigation shows modifications in the Raman spectra recorded between 30 and 3200 cm-1 that were interpreted as phase transitions undergone by the crystal between 1.3 and 1.9 GPa and between 3.6 and 5.1 GPa. Finally, stress was simulated on the unit cell of the crystal from ambient up to 5.0 GPa.

Assuntos

Isoleucina/química , Modelos Moleculares , Teoria da Densidade Funcional , Pressão , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Análise Espectral Raman/métodos

RESUMO

In this study, the vibrational frequencies of myristic acid (CH3(CH2)12COOH) were obtained using density functional theory calculations, and the results were compared with experimental Raman and infrared data. Additionally, Raman spectra of crystalline myristic acid were recorded in the 300-20 K range. Raman spectroscopy gives important insights into the effect of low temperatures on its monoclinic phase. X-ray diffraction was performed from 298 to 133 K to provide additional information about the cryogenic behavior of the crystals. These undergo a phase transformation, which was confirmed by differential scanning calorimetry through an enthalpy anomaly observed at low temperatures. Raman spectra and X-ray diffraction refinement of the cell parameters in combination with differential scanning calorimetry at low temperatures revealed slight modifications, confirming a conformational change in the myristic acid molecules involving rearrangement of dimers within the unit cell.

RESUMO

In this study, we report the antibacterial activity and modulation of antibiotic activity by Fe2(MoO4)3 microstructures obtained by the hydrothermal route without use of surfactants or organic additives. This material was characterized by X-ray diffraction (XRD), Raman spectroscopy and scanning electron microscopy (SEM) images. The XRD pattern showed that the Fe2(MoO4)3 crystallize in a monoclinic structure without secondary phases. Raman spectroscopy confirms the formation of Fe2(MoO4)3. SEM images show that the Fe2(MoO4)3 obtained have ball-of-yarn shaped morphology. In the antibacterial assays, strains of Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus were assayed by microdilution method to evaluate the antibacterial and modulatory-antibiotic activity with antibiotics as gentamicin, norfloxacin and imipenem. Against all bacteria, the Minimum Inhibitory Concentration (MIC) was Fe2(MoO4)3 ≥ 1024 µg/mL. This high MIC result must be associated with the fact of the iron be an essential microelement to the bacterial growth. However, when the Fe2(MoO4)3 was assayed in association with the antibiotics was observed an antagonistic effect demonstrated by an enhance of the MIC. This fact is associated directly with the pro-oxidative properties of metallic oxides. These compounds enhance the production of free radicals, as H2O2 and superoxide ions that can affect the cell structures as cell membrane and cell wall. Other effect is associated with the possible coordination of the metal, performing bonds with the chemical structure of the antibiotics, reducing their activity. Our results indicated that nanocompounds as Fe2(MoO4)3 can not be used as antimicrobial products for clinical usage, neither directly and neither in association with antibiotics.

Assuntos

Antibacterianos/farmacologia , Compostos Férricos/farmacologia , Molibdênio/farmacologia , Nanopartículas , Antibacterianos/química , Antibacterianos/toxicidade , Química Farmacêutica/métodos , Cristalização , Composição de Medicamentos , Farmacorresistência Bacteriana Múltipla , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Compostos Férricos/química , Compostos Férricos/toxicidade , Testes de Sensibilidade Microbiana , Estrutura Molecular , Molibdênio/química , Molibdênio/toxicidade , Oxirredução , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/crescimento & desenvolvimento , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento , Relação Estrutura-Atividade

RESUMO

Boric acid (H3BO3) is being used effectively nowadays in traps/baits for the management of Aedes aegypti L. and Aedes albopictus Skuse species of mosquitoes, which are the main spreading vectors worldwide for diseases such as malaria, dengue, and zika. Previously, we published results on the structural, electronic, and optical properties of its molecular triclinic H3BO3-2A and trigonal H3BO3-3T polymorphs within the framework of density functional theory (DFT). Because of the renewed importance of these materials, the focus of this work is on the vibrational properties of the bulk boric acid 2A and 3T polymorphs. We measured the infrared and Raman spectra of the former, which was accompanied and interpreted through state-of-the-art DFT calculations, supplemented by computations regarding the H3BO3 molecule and two-dimensional layers based on the bulk structures. We identify/assign their normal modes and find vibrational signatures for each polymorph as well as in- and out-of-plane motions and molecular vibrations, unveiling a nice agreement between the DFT level of theory employed and our improved spectroscopic measurements in the wavenumber ranges of 400-2000 cm-1 (infrared) and 0-1500 cm-1 (Raman). We show that a dispersion-corrected DFT functional within the generalized gradient approximation (GGA) can be very accurate in describing the vibrational properties of the boric acid polymorphs. Besides, several issues left open/not clearly resolved in previously published works on the vibrational mode assignments of the bulk and 2D sheets of boric acid are explained satisfactorily. Finally, phonon dispersions and associated densities of states were also evaluated for each polymorph along with their temperature-dependent DFT-calculated entropy, enthalpy, free energy, heat capacity, and Debye temperature. In particular, our DFT calculations suggest a possible way to differentiate the 2A and 3T boric acid polymorphs through Raman spectroscopy and heat capacity measurements.

RESUMO

In this paper we performed the study of two coprolites (fossilized feces) collected from the exposed levels of the Pedra de Fogo Formation, Parnaiba Sedimentary Basin, and Rio do Rasto Formation, Paraná Sedimentary Basin, both of the Palaeozoic era (Permian age). They were characterized using X-ray diffractometry, infrared, Raman and energy dispersive spectroscopy techniques in order to aid our understanding of the processes of fossilization and to discuss issues related to the feeding habits of the animals which generated those coprolites, probably cartilaginous fishes. The results obtained using a multitechnique approach showed that although these coprolites are from different geological formations, 3000km away from each other, they show the same major crystalline phases and elemental composition. The main phases found were hydroxyapatite, silica, calcite and hematite, which lead to infer that those coprolites were formed under similar conditions and produced by a similar group of carnivore or omnivore fishes.

Assuntos

Fenômenos Químicos , Fezes/química , Fósseis , Animais , Brasil , Imagem Óptica , Espectroscopia de Infravermelho com Transformada de Fourier , Análise Espectral Raman , Difração de Raios X

RESUMO

Raman spectra of bis(l-histidinate)nickel(II) monohydrate crystal were obtained for pressures up to 9.5GPa. Our results show the disappearance of some of the Raman modes and the appearance of other modes. These modifications evidence that the sample undergoes phase transitions at around 0.8 and 3.2GPa. The role played by the Ni ions and hydrogen bonds in the dynamics of the phase transitions is discussed. Under decompression, down to atmospheric pressure, the original Raman spectra are recovered, showing that both phase transitions are fully reversible.

RESUMO

A complete experimental study on the vibrational properties of palmitic and stearic acids crystallized in the Bm and C forms, both belonging to the monoclinic system with the P21/a (C2h5) space group, through polarized Raman and infrared spectroscopy, is reported in this paper. Density functional theory calculations were also performed to assign the normal modes and to help in the interpretation of the experimental data. The different polarizations were compared and their influence on the spectral profiles, in both the lattice and the internal mode regions, was discussed. In general, the Raman and infrared spectra exhibit accentuated differences among the polymorphic forms, which are associated with the different molecular modifications, defined as gauche and all-trans conformations. Insights about interaction among different groups are also furnished.

RESUMO

Cardiac remodeling is defined as changes in shape and function of the heart in response to aggression (pressure overload). The sarcoplasmic reticulum calcium ATPase cardiac isoform 2a (SERCA2a) is a known factor that influences function. A wide spectrum of studies report a decrease in SERCA2a in heart failure, but none evaluate it's the role in early isolated diastolic dysfunction in supravalvular aortic stenosis (AoS). Our hypothesis was that SERCA2a participates in such dysfunction. Thirty-day-old male Wistar rats (60-80 g) were divided into AoS and Sham groups, which were submitted to surgery with or without aorta clipping, respectively. After 6 weeks, the animals were submitted to echocardiogram and functional analysis by isolated papillary muscle (IPM) in basal condition, hypoxia, and SERCA2a blockage with cyclopiazonic acid at calcium concentrations of 0.5, 1.5, and 2.5 mM. Western-blot analyses were used for SERCA2a and phospholamban detection. Data analysis was carried out with Student's t-test and ANOVA. AoS enhanced left atrium and E and A wave ratio, with preserved ejection fraction. Basal condition in IPM showed similar increases in developed tension (DT) and resting tension (RT) in AoS, and hypoxia was similar between groups. After cyclopiazonic acid blockage, final DT was equally decreased and RT was similar between groups, but the speed of relaxation was decreased in the AoS group. Western-blot was uniform in all evaluations. The hypothesis was confirmed, since functional parameters regarding SERCA2a were changed in the AoS group.

Assuntos

Estenose Aórtica Supravalvular/complicações , Hipertrofia Ventricular Esquerda/fisiopatologia , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático/fisiologia , Disfunção Ventricular Esquerda/fisiopatologia , Animais , Estenose Aórtica Supravalvular/metabolismo , Proteínas de Ligação ao Cálcio/análise , Colágeno/análise , Diástole/fisiologia , Modelos Animais de Doenças , Ecocardiografia , Ventrículos do Coração/patologia , Ventrículos do Coração/fisiopatologia , Hipertrofia Ventricular Esquerda/etiologia , Hipertrofia Ventricular Esquerda/metabolismo , Hipóxia/metabolismo , Hipóxia/fisiopatologia , Indóis , Masculino , Contração Miocárdica/fisiologia , Ratos Wistar , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático/análise , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático/metabolismo , Fatores de Tempo , Disfunção Ventricular Esquerda/etiologia , Disfunção Ventricular Esquerda/metabolismo , Remodelação Ventricular/fisiologia

RESUMO

High-pressure Raman experiments were performed on Sm2Mo4O15 system up to 7.9GPa. We show that this system exhibits an irreversible structural amorphization at 5.0GPa. In contrast to any other molybdates and tungstates experiencing pressure-induced amorphization, this structural change in Sm2Mo4O15 has strongly first-order character. This amorphous phase can be originated from the hindrance of a crystalline structural phase transition from the P1¯ to P2/m structure. Additionally, the assignment of Raman modes of the ambient-pressure phase of Sm2Mo4O15 was proposed based on lattice dynamics calculations.

RESUMO

Single crystal of monoglycine nitrate has been studied by Raman spectroscopy under high pressures up to 5.5 GPa. The results show changes in lattice modes in the pressure ranges of 1.1-1.6 GPa and 4.0-4.6 GPa. The first change occurs with appearance of bands related to the lattice modes as well as discontinuity in the slope of dΩ/dP of these modes. Moreover, bands associated with the skeleton of glycine suggest that the molecule undergoes conformational modifications. The appearance of a strong band at 55 cm(-1) point to a second phase transition associated with the lattice modes, while the internal modes remain unchanged. These anomalies are probably due to rearrangement of hydrogen bonds. Additionally, decompression to ambient pressure shows that the phase transitions are reversible. Finally, the results show that the nitrate anions play an important role on the stability of the monoglycine nitrate crystal.