Evaluation of sound absorption capacity of asphalt mixtures

Noise generation is an environmental problem that affects human beings, animals and even plants. Several serious diseases have their development associated to the exposure of human beings to high levels of noise pressure, such as arterial hypertension, gastrointestinal changes, alterations in blood glucose and high heart rate, among others. Vehicle traffic is part of a group of noise-generating factors. Various mechanisms govern the generation and propagation of vehicle noises, which are produced mainly by motor vibration at speeds below 50 km/h and by the tire-pavement contact at speeds above 50 km/h. The noise generated by tire-pavement contact is the result of two components: aerodynamic noise (mainly related to the coating porosity), and mechanical noise (related to the coating texture). The noise generation according to these two components may be mitigated by using special asphalt mixtures. This work evaluates the sound absorption of four different types of asphalt mixtures (common dense-graded asphalt mixture, dense-graded rubberized asphalt mixture, rubberized porous coat with void volumes varying from 22% to 27%, and rubberized open-graded friction course) and the effect of granulometry and void volume of each mixture on the sound absorption coefficient. Mixture slabs were molded in a slab compactor developed by LCPC (Laboratoire Central des Ponts et Chaussées) and specimens were extracted from each one for assessing the sound absorption capacity in the laboratory. The acoustic behavior was evaluated according to standard ISO 10534-2, using impedance tubes. Results showed that sound absorption is strongly influenced by void percentage, interconnected void percentage and layer thickness.     

Reactions with Weakly Bound Nuclei,at near Barrier Energies,and the Breakup and Transfer Influences on the Fusion and Elastic Scattering

We present a brief review of the reaction mechanisms involved in collisions of weakly bound projectiles with tightly bound targets, at near-barrier energies. We discuss systematic behaviors of the data, with emphasis in fusion, breakup, nucleon transfer and elastic scattering. The dependence of the breakup cross section on the charge and mass of the target is discussed, and the influence of the breakup channel on complete fusion is investigated. For this purpose, we compare reduced fusion cross sections with a benchmark universal curve. The behaviors observed in the comparisons are explained in terms of polarization potentials and of nucleon transfer followed by breakup. The influence of the breakup process on elastic scattering is also discussed. Some apparent contradictions between results of different authors are explained and some perspectives of the field are presented.     

Physicochemical characterization of dipeptidyl peptidase-4 inhibitor alogliptin in physical mixtures with excipients

Alogliptin (ALG) is a hypoglycemic drug used in diabetes which inhibits the enzyme dipeptidyl peptidase-4 (DPP-4), preventing the degradation of incretins, stimulating insulin secretion. The physicochemical characteristics of ALG were evaluated by differential scanning calorimetry (DSC), thermogravimetry (TG) and scanning electron microscopy equipped with energy-dispersive X-ray spectrometer (SEM/EDS). The compatibility studies were carried out between ALG and excipients (physical mixtures, 1:1) using DSC, TG, diffuse reflectance Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRPD) and hot-stage microscopy. ALG presented purity near to 99%, melted in the range of 179.4–187.2 °C, followed by decomposition which started in 198.0 °C. SEM/EMS analysis of ALG presented irregular crystals and traces of impurities as copper and lead. DSC investigations obtained by physical mixtures showed minor alterations in the melting ranges of ALG with mannitol, magnesium stearate and commercial tablets. Solubilization of ALG in the fused excipient was observed by hot-stage microscopy between mannitol and ALG, and in tablets. The interaction observed in the mixture with magnesium stearate is due to the melting of the excipient and drug separately, first the excipient and then the drug. FTIR showed additional bands related to the excipients. XRPD proved that ALG has a crystal form and no alterations in the ALG profile were observed after the mixtures. ALG was compatible with all excipients tested. These results were important to understand the characteristics, stability and compatibility of the drug, and proved to be useful in preformulation studies.

     

Hologram QSAR Models of 4-[(Diethylamino)methyl]-phenol Inhibitors of Acetyl/Butyrylcholinesterase Enzymes as Potential Anti-Alzheimer Agents

Hologram QSAR models were developed for a series of 36 inhibitors (29 training set and seven test set compounds) of acetyl/butyrylcholinesterase (AChE/BChE) enzymes, an attractive molecular target for Alzheimer's disease (AD) treatment. The HQSAR models (N = 29) exhibited significant cross-validated (AChE, q² = 0.787; BChE, q² = 0. 904) and non-cross-validated (AChE, r² = 0.965; BChE, r² = 0.952) correlation coefficients. The models were used to predict the inhibitory potencies of the test set compounds, and agreement between the experimental and predicted values was verified, exhibiting a powerful predictive capability. Contribution maps show that structural fragments containing aromatic moieties and long side chains increase potency. Both the HQSAR models and the contribution maps should be useful for the further design of novel, structurally related cholinesterase inhibitors.     

Cytotoxic gold compounds: synthesis, biological characterization and investigation of their inhibition properties of the zinc finger protein PARP-1

The new gold(III) complexes: [Au{2-(2'-pyridyl)imidazolate}Cl(2)] and [Au{2,6-bis(2'-benzimidazolate)pyridine}(OCOCH(3))] and the mono- and binuclear gold(I) complexes: [Au{2-(2'-pyridyl)imidazole}(PPh(3))](PF(6)), [Au(2-phenylimidazolate)(DAPTA)] (DAPTA = 3,7-diacetyl-1,3,7-triaza-5-phosphabicyclo[3.3.1]nonane), [(PPh(3)Au)(2)(2-R-imidazolate)](PF(6)) (R = 2-C(5)H(4)N, Ph) have been synthesized and characterized. The structure of the [(PPh(3)Au)(2){2-(2'-pyridyl)imidazolate)](PF(6)) complex was also characterized by X-ray crystallography. The antiproliferative properties of the complexes were assayed against human ovarian carcinoma cell lines, either sensitive (A2780) or resistant to cisplatin (A2780cisR), human mammary carcinoma cells (MCF7) and non-tumorigenic human kidney (HEK293) cells. Most of the studied compounds showed important cytotoxic effects. Interestingly, the compounds containing the 2-(2'-pyridyl)imidazolate ligand showed selectivity towards cancer cells with respect to the non-tumorigenic ones, with the dinuclear compound [(PPh(3)Au)(2){2-(2'-pyridyl)imidazolate)](PF(6)) being the most active. Some compounds were also screened for their inhibitory effect of the zinc-finger protein PARP-1, essential for DNA repair and relevant to the mechanisms of cancer cell resistance to cisplatin. Interaction studies of the compounds with the model protein ubiquitin were undertaken by electrospray ionization mass spectrometry (ESI MS). The results are discussed in relation to the putative mechanisms of action of the cytotoxic gold compounds.     

Planar Integrated Optical Waveguide Sensor for Isopropyl Alcohol in Aqueous Media

An attenuated total reflection (ATR) sensor for water-miscible organic solvents was constructed using a combination of sol-gel processing and integrated optical waveguide (IOW) technologies. The sensor consisted of single-mode, sol-gel based planar waveguide coated with a 40 nm thick, porous sol-gel indicator layer prepared from methyltriethoxysilane and doped with methyl red. The response of the senor to aqueous isopropyl alcohol (IPA) was investigated. Solvation of the indicator dye by IPA causes the absorbance spectrum to undergo a blue shift coupled with an increase in molar absorptivity. IPA was detected by measuring changes in ATR of the guided mode at 488 nm. A response curve extending from 1 to 100% (v/v) IPA in water was constructed for the sensor, from which a detection limit of 0.7% (v/v) IPA/water was estimated. Response and reversal times were typically less than one minute, making this sensor potentially attractive for on-line monitoring applications. The rapid response characteristics are attributable to relatively weak, reversible interactions between the indicator and analyte.     

New crystals in the lithium sulfate family

The preparation and structures of caesium lithium sulfate, Cs_1.15Li_2.85(SO₄)₂, and caesium lithium rubidium sulfate, Cs_0.90Li_2.88Rb_0.22(SO₄)₂, are described and discussed in the context of simple and double sulfate polymorphism. The latter structure is related to the former through the substitution of Rb for Cs. In both crystals, the sulfate ions occupy two non‐equivalent sites, but the ions are disordered in Cs_1.15Li_2.85(SO₄)₂.     

Platinum(II) complexes of 2-, 3-, and 4-formyl-pyridine thiosemicarbazone and 2-, 3- and 4-acetyl-pyridine thiosemicarbazone

Seven platinum(II) complexes isolated from thiosemicarbazones derived from 2-, 3- and 4-formylpyridine and 2-, 3-, and 4-acetylpyridine have been characterised by microanalyses, molar conductivities and by their i.r. and ¹H-n.m.r. spectra.