The present work reports the antitumor activity and a comprehensive study of the Cu(II) complex with 1,10-phenanthroline and
l
-tyrosine, synthesized by slow solvent evaporation method. X-ray powder ...diffraction (XRPD) showed that the complex crystallizes in a monoclinic structure with
P
2
1
/c
-space group. All IR- and Raman-active bands were assigned and vibrational properties were evaluated under solvation effects from quantum chemical calculations using density functional theory (DFT). Additionally, optimized geometry, electrostatic potential surface, spatial distribution, and energies of molecular orbitals HOMO and LUMO, as well as chemical reactivity indexes, were obtained using PBE1PBE theoretical level. Antitumor activity of the complex was evaluated through cytotoxic tests in vitro in tumor cell lines PC3 and SNB-19, presenting IC
50
equal to 1.5 μM and 2.9 μM, respectively. Additionally, ADME parameters were evaluated to study the drug-like properties of the synthesized complex. Therefore, our findings suggest that the complex presents a promising antitumor activity, with the potential to be used in cancer chemotherapy treatment.
Neural Network Model to Predict a Storm Surge de Oliveira, Marilia M. F.; Ebecken, Nelson Francisco F.; de Oliveira, Jorge Luiz Fernandes ...
Journal of applied meteorology and climatology,
01/2009, Letnik:
48, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The southeastern coast of Brazil is frequently affected by meteorological disturbances such as cold fronts, which are sometimes associated with intense extratropical cyclones. These disturbances ...cause oscillations on the sea surface, generating low-frequency motions. The relationship of these meteorologically driven forces in low frequency to the storm-surge event is investigated in this work. A method to predict coastal sea level variations related to meteorological events that use a neural network model (NNM) is presented here. Pressure and wind values from NCEP–NCAR reanalysis data and tide gauge time series from the Cananéia reference station in São Paulo State, Brazil, were used to analyze the relationship between these variables and to use them as input to the model. Meteorological influences in the sea level fluctuations can be verified by filtering the astronomical tide frequencies for periods lower than tidal cycles (periods higher than 24 h). Thus, a low-pass filter was applied in the tide gauge and meteorological time series for periods lower than tides to identify more readily the interactions between coastal sea level response and atmospheric-driven forces. Statistical analyses on time and frequency domain were used. Maxima correlations and coherence between the low-frequency sea level and meteorological series could be defined using the time lag of the NNM input variables. The model was tested for 6-, 12-, 18-, and 24-hourly forecasts, and the results were compared with filtered sea level values. The results show that this model is able to capture the effects of atmospheric and oceanic interactions. It can be considered to be an efficient model for predicting the nontidal residuals and can effectively complement the standard constant harmonic analysis model. A case study of a storm that impacted coastal areas of southeastern Brazil in March 1998 was analyzed and indicates that the neural network model can be effectively utilized in the Cananéia region.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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•5-methyluridine hemihydrate (5 mU) crystals were obtained by slow evaporation method.•Properties and vibrational spectra calculated by DFT presented good results in comparison with ...experimental data.•5 mU crystal suffers a change from orthorhombic to triclinic system due to the exit of water from the crystalline structure.•Anhydrous system undergoes a phase change from triclinic to monoclinic system.
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.
Nanostructured Ni-containing spinel oxide catalysts were obtained using a nanocasting method. Analyses by XRD, TEM, TPD-CO2 and TPR showed that Nio and/or Coo entities with high accessibility to CH4 ...and CO2 were responsible for high catalytic performance in the dry reforming of methane. The NiCo (Coo and Nio dispersed on NiAl2O4) and NiAl (Nio dispersed on NiAl2O4) species were highly active for CH4 conversion, whereas Nio dispersed on either Fe3O4–Co3O4 or CeO2–NiAl2O4 provided a lower catalytic performance due to active phase degradation. The higher activity exhibited by NiAl compared to NiCo was related to the higher activity of nickel for CO2 decomposition, while its remarkable stability seemed to be due to the presence of well dispersed nanoparticles involved in long-term conversion because they produced non-deactivating carbon deposits, as suggested by Raman analyses.
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► Nanocasting Ni, Co-containing catalysts were synthesized. ► Characterisation by thermal analysis techniques, XRD, TEM and TPR indicated that Coo and Nio entities with high accessibility to CH4 and CO2. ► Analyses of the spent catalysts by TEM, Raman and TPO demonstrated that coking was the main cause of catalyst deactivation. ► Graphitic and filaments of carbon.
Adsorption isotherms for nitrate ions. Display omitted
► Removal of inorganic anions from aqueous solution through batch process. ► Characterizations by full factorial design, FTIR, elemental ...analysis, SEM and XRD. ► Kinetics of adsorption and Freundlich, SIPS, Redlich–Peterson and Temkin models. ► Modified coconut powder was efficient to remove nitrate, sulfate and phosphate.
The powder of green coconut shell (Coco nuscifera L.) was chemically modified and used to remove inorganic anions from aqueous solution through batch process. The solid was modified with ammonium quaternary salt (2-hidroxypropyltrimethyl ammonium chloride) and characterized by a full factorial design. The FTIR, elemental analysis, SEM and X-ray measurements were performed. FTIR analysis indicated that the coconut bagasse interacted with NH2 groups of the surfactant. Initial anion concentration, pH and adsorbent dosage were investigated in this study, as well as the kinetics of adsorption and isotherms for the modified coconut bagasse. Kinetics of adsorption was examined by means of three kinetic models, i.e., pseudo-first-order, pseudo-second-order and intraparticle diffusion models. Pseudo-second-order kinetic model showed good agreement with the experimental data. Data on equilibrium were evaluated by using Langmuir, Freundlich, SIPS, Redlich–Peterson, Temkin models. It was observed that the experimental data fits well to Langmuir, SIPS, and Redlich–Peterson equations. The results indicated that the modified coconut powder exhibited potential application for removal of nitrate, sulfate and phosphate from aqueous solutions.
Statistical analysis of extreme values is applied to wind data from National Centers for Environmental Prediction and National Center for Atmospheric Research reanalysis grid points over the ocean ...region bounded at 23°S and 40°W and 42°W towards the south and southeastern Brazilian coast. The period of analysis goes from 1975 to 2006. The generalized extreme value and generalized Pareto distributions are employed for annual and daily maxima, respectively. The Pareto–Poisson point process characterization is also used to analyze peaks over threshold. Return levels for 10, 25, 50, and 100 years are calculated at each grid point. However, most of the reanalysis data fall within 1–10-year return periods, suggesting that hazardous wind speed with low probability (return periods of 50–100) have rarely measured in this period. Wide confidence intervals on these levels show that there is not enough information to make predictions with any degree of certainty to return periods over 100 years. Low extremal index (
θ
) values are found for excess wind speeds over a high threshold, indicating the occurrence of consecutively high peaks. In order to obtain realistic uncertainty information concerning inferences associated with threshold excesses, a declustering method is performed, which separates the excesses into clusters, thereby rendering the extreme values more independent.
•Selective catalytic reduction of NOx by CO.•Mo helping the dispersion of the Co, Ni or Pt active sites.•Pto and Mo6+ redox pair and low interaction PtMo with the support.•High CO and NOx adsorption ...to form CO2 and N2.•Inhibition of sulfatation and coking over PtMo/Al2O3-La2O3.
Promotional effect of molybdenum on bimetallic Al2O3-La2O3-based catalysts was investigated in the selective catalytic reduction (CO-SCR) reaction. The physicochemical properties of the solids were evaluated through X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), Scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), nitrogen physisorption analyses, Temperature programmed reduction (TPR), NH3-temperature programmed desorption (NH3-TPD) and Transmission electron microscopy (TEM). Structural characterizations confirmed the formation of porous nanostructured solids with molybdenum helping the dispersion of the Ni or Pt active sites close to the molybdenum particles. The catalysts have acid sites of medium to low strengths effectively enhancing the catalytic activity of the solids. Investigation of the various active sites revealed PtMo supported on Al2O3-La2O3 as the best catalyst using distinct temperatures and poisoning conditions in the CO-SCR reaction, rather than NiMo and CoMo counterparts. The oxidation of the species and phase transformation were more significant on the CoMo than NiMo catalyst, with the latter having a modest performance. The low interaction of the PtMo with the support provided the formation of a Pto and Mo6+ redox pair, which resulted in high CO and NOx adsorption to form CO2 and N2. This was due to the synergistic effect of valence-rich Mo transition oxides with Pt species, resulting in the inhibition of irreversible sulfatation and coking over PtMo/Al2O3-La2O3 catalyst.
In this study, X‐ray diffraction confirms the crystallization of aqua(1,10‐phenanthroline)(L‐serinato)copper(II) nitrate in the triclinic system (P‐1). Density functional theory calculations are used ...to assign the vibration bands of Cu2+ ion and phenanthroline (phen) and L‐serine (L‐ser) ligands obtained by Raman and Fourier‐transform infrared spectroscopy. Physical and analytical properties, evaluated by computational study utilizing CrystalExplorer software, show the prevalence of H···O/O···H interaction. Thermal analyses show that the complex is stable in the temperature interval of 300–390 K. For temperatures above 390 K, the elimination of coordinated water molecules (380–430 K), mass loss of serine (440–660 K), and material decomposition process above 660 K. The solubility of the complex in water reaches 21.4 mg mL−1 at 35 °C. Parameters of drug‐likeness and assessment of absorption, distribution, metabolism, and excretion (ADME) properties are calculated. The in vitro cytotoxic assays against the cancer cell line of the HCT‐116 type (human colorectal carcinoma) exhibits toxicity (IC50 = 1.88 µm and selectivity index of 2.17) for the complex. The results highlight the potential of ternary copper complexes such as Cu(phen)(L‐ser)(H2O)NO3 for anticancer drug development as attractive, efficient, and low‐cost materials.
Structural, spectroscopy, physical, and analytical properties of aqua(1,10‐phenanthroline)(L‐serinato)copper(II) nitrate complex are investigated by full Density Functional Theory‐based calculation. Vibration modes indicate the complexation of material with the prevalence of H···O/O···H interaction. The complex remains stable from 300 to 390 K. In vitro, cytotoxicity against HCT‐116 cancer cells shows an IC50 of 1.88 µm and a selectivity index of 2.17.
Low-molecular-weight heparin represent a significant advancement in anticoagulant therapy with enoxaparin being a prominent example obtained exclusively through the fragmentation of porcine ...intestinal heparin. However, escalating demand and limited resources have raised concerns about enoxaparin supplementation. The current challenge involves exploring alternative heparin sources for large-scale enoxaparin production with bovine intestinal heparin emerging as a promising option. Our study demonstrates that enoxaparin derived from the available bovine heparin preparation differs significantly from the reference compound. Yet, the implementation of a straightforward purification step yields a preparation termed “high-anticoagulant bovine heparin”. Fragmentation of this purified product through β-elimination produces enoxaparin akin to the standard from a porcine origin. To ensure physicochemical similarity, we employed various spectroscopic, enzymatic, and chromatographic tests to compare the new bovine-derived enoxaparin with the original porcine compound. Biological activity was confirmed through in vitro coagulation assays and assessments using an animal model of venous thrombosis. Our study affirms that the β-elimination reaction cleaves the bovine heparin chain without preferential breaks in regions with different sulfation patterns. Additionally, we scrutinized decasaccharides purified from enoxaparin preparations, providing a comprehensive demonstration of the similarity between products obtained from porcine and bovine heparin. In summary, our findings indicate that an enoxaparin equivalent to the original porcine-derived product can be derived from bovine heparin, given that the starting material undergoes a simple purification step.
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