Configurational Entropy and Newton's Law in Double Sine‐Gordon Braneworlds

The Shannon‐like entropic measure of spatially localized functions for a 5D braneworld generated by a double sine‐Gordon (DSG) potential is evaluated. The differential configurational entropy (DCE) has been shown in several recent works to be a configurational informational measure (CIM) that selects critical points and brings out phase transitions in confined energy models with arbitrary parameters. The DSG scenario is selected because it presents an energy‐degenerate spatially localized profile where the solutions to the scalar field demonstrate critical behavior that is only a result of geometrical effects. As is shown, the DCE evaluation provides a method for predicting the existence of a transition between the phases of the domain wall solutions. Moreover, the entropic measure reveals information about the model that is capable of describing the phase sector where resonance modes on the massive spectra of the graviton is obtained. The graviton resonance lifetimes are related to the existence of scales on which 4D gravity is recovered. Thus, the critical points defined by the CIMs with the existence of resonances and their lifetimes are correlated. To extend the research regarding this system, the corrections to Newton's law coming from the graviton modes are calculated.     

Testing the cosmic conservation of photon number with type Ia supernovae and ages of old objects

In this paper, we obtain luminosity distances by using ages of 32 old passive galaxies distributed over the redshift interval \(0.11< z < 1.84\) and test the cosmic conservation of photon number by comparing them with 580 distance moduli of type Ia supernovae (SNe Ia) from the so-called Union 2.1 compilation. Our analyses are based on the fact that the method of obtaining ages of galaxies relies on the detailed shape of galaxy spectra but not on galaxy luminosity. Possible departures from cosmic conservation of photon number is parametrized by \(\tau (z) = 2 \upvarepsilon z\) and \(\tau (z) = \upvarepsilon z/(1+z)\) (for \(\upvarepsilon =0\) the conservation of photon number is recovered). We find \(\upvarepsilon =0.016^{+0.078}_{-0.075}\) from the first parametrization and \(\upvarepsilon =-\,0.18^{+0.25}_{-0.24}\) from the second parametrization, both limits at 95% c.l. In this way, no significant departure from cosmic conservation of photon number is verified. In addition, by considering the total age as inferred from Planck (2015) analysis, we find the incubation time \(t_{inc}=1.66\pm 0.29\) Gyr and \(t_{inc}=1.23\pm 0.27\) Gyr at 68% c.l. for each parametrization, respectively.     

Raman investigation of ZnO and Zn1−xMnxO nanocrystals synthesized by precipitation method

Zn_1?xMn_xO nanocrystal samples have been successfully synthesized using the chemical precipitation method in aqueous solution. Comparing with pure ZnO NC, the Raman data recorded from the manganese-doped nanocrystals shows an enhancement of the peaks located at 334 and 439 cm^?1. Besides, a new feature at 659 cm^?1 emerges. X-ray diffraction (XRD) of the as-precipitated nanocrystal samples illustrates that Mn-doping only makes the XRD peaks of the as-precipitated Mn-doped nanocrystals shift towards lower angle values, but the crystal structure of bulk ZnO is still preserved in the Mn-doped samples. Hence, the high quality Zn_1?xMn_xO (x ? 0) nanocrystals are formed through the replacement of zinc ions by manganese ions.     

Searching Anti-Zika Virus Activity in 1H-1,2,3-Triazole Based Compounds

Zika virus (ZIKV) is a mosquito-borne virus belonging to the Flaviviridae family and is responsible for an exanthematous disease and severe neurological manifestations, such as microcephaly and Guillain-Barré syndrome. ZIKV has a single strand positive-sense RNA genome that is translated into structural and non-structural (NS) proteins. Although it has become endemic in most parts of the tropical world, Zika still does not have a specific treatment. Thus, in this work we evaluate the cytotoxicity and antiviral activities of 14 hybrid compounds formed by 1H-1,2,3-triazole, naphthoquinone and phthalimide groups. Most compounds showed low cytotoxicity to epithelial cells, specially the 3b compound. After screening with all compounds, 4b was the most active against ZIKV in the post-infection test, obtaining a 50% inhibition concentration (IC₅₀) of 146.0 µM and SI of 2.3. There were no significant results for the pre-treatment test. According to the molecular docking compound, 4b was suggested with significant binding affinity for the NS5 RdRp protein target, which was further corroborated by molecular dynamic simulation studies.     

New Imatinib Derivatives with Antiproliferative Activity against A549 and K562 Cancer Cells

Tyrosine kinase enzymes are among the primary molecular targets for the treatment of some human neoplasms, such as those in lung cancer and chronic myeloid leukemia. Mutations in the enzyme domain can cause resistance and new inhibitors capable of circumventing these mutations are highly desired. The objective of this work was to synthesize and evaluate the antiproliferative ability of ten new analogs that contain isatins and the phenylamino-pyrimidine pyridine (PAPP) skeleton, the main pharmacophore group of imatinib. The 1,2,3-triazole core was used as a spacer in the derivatives through a click chemistry reaction and gave good yields. All the analogs were tested against A549 and K562 cells, lung cancer and chronic myeloid leukemia (CML) cell lines, respectively. In A549 cells, the 3,3-difluorinated compound (3a), the 5-chloro-3,3-difluorinated compound (3c) and the 5-bromo-3,3-difluorinated compound (3d) showed IC₅₀ values of 7.2, 6.4, and 7.3 μM, respectively, and were all more potent than imatinib (IC₅₀ of 65.4 μM). In K562 cells, the 3,3-difluoro-5-methylated compound (3b) decreased cell viability to 57.5% and, at 10 µM, showed an IC₅₀ value of 35.8 μM (imatinib, IC₅₀ = 0.08 μM). The results suggest that 3a, 3c, and 3d can be used as prototypes for the development of more potent and selective derivatives against lung cancer.     

Comparative study of specific heat capacities of some vegetable oils obtained by DSC and microwave oven

Summary TG and DSC analyses were carried out in this work to evaluate the changes in the denaturation of human hair keratin submitted to different chemical effects. Hair bleaching and chlorinating treatments caused changes in the denaturation temperatures and denaturation enthalpies of hair keratin. Bleached hair and hair kept in a chlorinated solution presented a lower denaturation enthalpy and a higher denaturation temperature compared to the control hair sample. The TG and DSC analyses allowed to quantify the degradation level of hair fibers after the chemical treatments. AFM was also utilized to characterize the morphological alterations in the hair fiber surfaces caused by the chlorinating and bleaching treatments.     

Application of a dipping procedure to construct a241Am skull phantom

The construction of reliable bone phantoms to calibrate whole body counting facilities for bone-seeking radionuclides has been a challenge for several research institutes. Different techniques have been applied to get uniform distribution of those nuclides in bone tissue. A²⁴¹Am skull phantom was developed at the Institute of Radiation Protection and Dosimetry/Brazilian Nuclear Energy Commission's (IRD/CNEN) Whole Body Counting facility, using a dipping procedure. Preliminary tests were performed using non-radioactive ink solution. The first step was to choose the appropriate solvent to be used, since it was observed that acid solutions attack bone tissue. At the second step, pieces of skull were dipped into those solutions to check the extent and homogeneity of the penetration. The third step consisted of verifying the dipping time using a²⁴¹Am standard solution. The homogeneity was checked with a high-purity germanium detector. Tissue-equivalent material was used to cover the skull surface and to simulate the low energy X and gamma radiation attenuation. The calibration factor and the detection limit were calculated for two phoswich detectors positioned at each side of the head, which is the standard geometry for this kind of measurement.     

Determination of formaldehyde in Brazilian alcohol fuels by flow-injection solid phase spectrophotometry

In this work, a solid phase spectrophotometric method in association with flow injection analysis for formaldehyde determination has been developed with direct measurement of light-absorption in C₁₈ material. The 3,5-diacetyl-1,4-dihydrolutidine produced from the reaction between formaldehyde and fluoral P was quantitatively retained on C₁₈ support and the spectrophotometric detection was performed simultaneously at 412 nm. The retained complex was quickly eluted from C₁₈ material with the eluent stream consisting of a 50% (v/v) ethanol solution. The results showed that the proposed method is simple, rapid and the analytical response is linear in the concentration range of 0.050-1.5 mg L⁻¹. The limit of detection was estimated as 30 μg L⁻¹ and the R.S.D. 2.2% using a sample volume of 625 μL. The system presented an analytical throughput of 20 determinations per hour. The method was successfully applied in the determination of formaldehyde in ethanol fuel.