Effect of Nonionic Surfactants on the Crystallinity and Thermal Stability of Poly(vinyl alcohol) Film

In this study, poly(vinyl alcohol) (PVA)/surfactant films were prepared by casting technique. Two nonionic surfactants with different alkyl chain lenghts (Tween 20 and Tween 40) were used. PVA/Tween 20 and PVA/Tween 40 films were characterized by means of Fourier Transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). FTIR spectra of PVA/Tween films indicated the presence of hydrogen bond interactions between the Tween surfactants and PVA. XRD results showed that the incorporation of Tween 20 and 40 into the PVA film decreased the crystallinity of PVA.TGA curves revealed an increase in the thermal stability of PVA film in the presence of the surfactants. DOI: http://dx.doi.org/10.17807/orbital.v12i4.151

Effect of Nonionic Surfactants on the Crystallinity and Thermal Stability of Poly(vinyl alcohol) Film

In this study, poly(vinyl alcohol) (PVA)/surfactant films were prepared by casting technique. Two nonionic surfactants with different alkyl chain lenghts (Tween 20 and Tween 40) were used. PVA/Tween 20 and PVA/Tween 40 films were characterized by means of Fourier Transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). FTIR spectra of PVA/Tween films indicated the presence of hydrogen bond interactions between the Tween surfactants and PVA. XRD results showed that the incorporation of Tween 20 and 40 into the PVA film decreased the crystallinity of PVA.TGA curves revealed an increase in the thermal stability of PVA film in the presence of the surfactants. DOI: http://dx.doi.org/10.17807/orbital.v12i4.151

Unrevealing the interactive effects of climate change and oil contamination on lab-simulated estuarine benthic communities

There is growing concern that modifications to the global environment such as ocean acidification and increased ultraviolet radiation may interact with anthropogenic pollutants to adversely affect the future marine environment. Despite this, little is known about the nature of the potential risks posed by such interactions. Here, we performed a multifactorial microcosm experiment to assess the impact of ocean acidification, ultraviolet radiation B (UV-B) and oil hydrocarbon contamination on sediment chemistry, the microbial community (composition and function) and biochemical marker response of selected indicator species. We found that increased ocean acidification and oil contamination in the absence of UV-B will significantly alter bacterial composition by, among other changes, greatly reducing the relative abundance of Desulfobacterales, known to be important oil hydrocarbon degraders. Along with changes in bacterial composition, we identified concomitant shifts in the composition of aromatic hydrocarbons in the sediment and an increase in oxidative stress effects on our indicator species. Interestingly, our study identifies UV-B as a critical component in the interaction between these factors, since its presence alleviates harmful effects caused by the combination of reduced pH and oil pollution. The model system used here shows that the interactive effect of reduced pH and oil contamination can adversely affect the structure and functioning of sediment benthic communities, with the potential to exacerbate the toxicity of oil hydrocarbons in marine ecosystems

Serovar-dependent differences in Hfq-regulated phenotypes in actinobacillus pleuropneumoniae

The RNA chaperone Hfq regulates diverse processes in numerous bacteria. In this study, we compared phenotypes (growth rate, adherence, response to different stress conditions, and virulence in Galleria mellonella) of wild-type (WT) and isogenic hfq mutants of three serovars (1, 8 and 15) of the porcine pathogen A. pleuropneumoniae. Similar growth in rich broth was seen for all strains except Ap1∆hfq, which showed slightly reduced growth throughout the 24 hour time course, and the complemented Ap8∆hfqC mutant had a prolonged lag phase. Differences were seen between the three serovar WT strains regarding adherence, stress response and virulence in G. mellonella, and deletion of hfq affected some, but not all of these phenotypes, depending on serovar. Complementation by expression of cloned hfq from an endogenous promoter only restored some WT phenotypes, indicating that complex regulatory networks may be involved, and that levels of Hfq may be as important as presence/absence of the protein regarding its contribution to gene regulation. Our results support that Hfq is a pleiotropic global regulator in A. pleuropneumoniae, but serovar-related differences exist. These results highlight the importance of testing multiple strains/serovars within a given species when determining contributions of global regulators, such as Hfq, to expression of complex phenotypes

Industrial scale isolation, structural and spectroscopic characterization of epiisopiloturine from Pilocarpus microphyllus stapf leaves: a promising alkaloid against schistosomiasis

This paper presents an industrial scale process for extraction, purification, and isolation of epiisopiloturine (EPI) (2(3H)- Furanone,dihydro-3-(hydroxyphenylmethyl)-4-[(1-methyl-1H-imidazol-4-yl)methyl]-, [3S-[3a(R*),4b]]), which is an alkaloid from jaborandi leaves (Pilocarpus microphyllus Stapf). Additionally for the first time a set of structural and spectroscopic techniques were used to characterize this alkaloid. EPI has shown schistomicidal activity against adults and young forms, as well as the reduction of the egg laying adult worms and low toxicity to mammalian cells (in vitro). At first, the extraction of EPI was done with toluene and methylene chloride to obtain a solution that was alkalinized with ammonium carbonate. The remaining solution was treated in sequence by acidification, filtration and alkalinization. These industrial procedures are necessary in order to remove impurities and subsequent application of the high performance liquid chromatography (HPLC). The HPLC was employed also to remove other alkaloids, to obtain EPI purity higher than 98%. The viability of the method was confirmed through HPLC and electrospray mass spectrometry, that yielded a pseudo molecular ion of m/z equal to 287.1 Da. EPI structure was characterized by single crystal X-ray diffraction (XRD), 1H and 13C nuclear magnetic resonance (NMR) in deuterated methanol/chloroform solution, vibrational spectroscopy and mass coupled thermal analyses. EPI molecule presents a parallel alignment of the benzene and the methyl imidazol ring separated by an interplanar spacing of 3.758 Å indicating a π-π bond interaction. The imidazole alkaloid melts at 225°C and decomposes above 230°C under air. EPI structure was used in theoretical Density Functional Theory calculations, considering the single crystal XRD data in order to simulate the NMR, infrared and Raman spectra of the molecule, and performs the signals attribution

Química na Hora do Recreio

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Baropodometry on women suffering from chronic pelvic pain - a cross-sectional study

<p>Abstract</p> <p>Background</p> <p>Previous studies have associated chronic pelvic pain with a stereotyped pattern of movement and posture, lack of normal body sensations, a characteristic pain distribution. We aimed at evaluating if these postural changes are detectable in baropodometry results in patients with chronic pelvic pain.</p> <p>Methods</p> <p>We performed a prospective study in a university hospital. We selected 32 patients suffering from chronic pelvic pain (study group) and 30 women without this pathology (regular gynecological work out - control group). Pain scores and baropodometric analysis were performed.</p> <p>Results</p> <p>As expected, study group presented higher pain scores than control group. Study and control groups presented similar averages for the maximum pressures to the left and right soles as well as soles supports in the forefeet and hind feet. Women suffering from chronic pelvic pain did not present differences in baropodometric analysis when compared to healthy controls.</p> <p>Conclusions</p> <p>This data demonstrates that postural abnormalities resulting from CPP could not be demonstrated by baropodometric evaluation. Other postural measures should be addressed to evaluate pelvic pain patients.</p

Áudios para aulas de Química: uma análise do Portal Dia a Dia Educação

A utilização de áudios em sala de aula não tem sido muito utilizada nos últimos anos, entretanto existem portais que disponibilizam esse recurso como material didático. Um destes portais é o Dia a Dia Educação da Secretaria do Estado do Paraná-SEED. Assim este artigo apresenta uma análise realizada a partir de áudios que estão disponibilizados nesse portal. Nossa intenção foi verificar a funcionalidade e a recepção dos estudantes para este tipo de recurso. As avaliações demonstram que é possível utilizar esse recurso em sala de aula, entretanto é preciso superar algumas dificuldades técnicas impostas pelos recursos tecnológicos oferecidos à professores e estudantes nas escolas do Paraná