Dry Fractionation of Cupuassu (Theobroma grandiflorum) Fat: Physical–Chemical Properties and Polymorphic Behavior

Physical chemical properties of cupuassu fat were modified by dry fractionation. Stearin and olein fractions were obtained at 29, 26, and 24 °C. Polymorphic behavior of unfractionated cupuassu fat (UCF) and its fractions were studied in situ by small-angle (SAXS) and wide-angle (WAXS) X-ray scattering using synchrotron light. Polymorphic transitions were followed in real time tempering samples with a thermal cycle. For UCF, the main polymorphic form crystallized under selected conditions was the β’₂. α and β’₁-forms appeared in trace amounts. β₂-form was obtained after storage at 25 °C for 3 months. Stearins obtained at 26 (S-26) and 24 °C (S-24) showed a similar polymorphic behavior. However, S-26 with improved physical properties might be more suitable for chocolate production or as a trans-fat alternative than UCF. Stearin fraction obtained at 29 °C (S-29) had a complex polymorphic behavior. The α-form was the first polymorphic form detected followed by β’₂-form. There was a polymorphic transition from α to β’₁-form but no transition between β’-forms. They were independent to each other showing fractionation in two different solid solutions. Increased contents of the triacylglycerols (TAG) SOA and SOB together with lower contents of SOO compared to UCF led to co-crystallization because there was no complete compatibility among all TAG present in S-29. β₁-form crystallized after storage forming crystals with a double-layer arrangement and a characteristic morphology. This form could be useful for accelerating crystallization process in melted liquid systems.     

Carbazole‐based electroluminescent devices obtained by vacuum evaporation

Transparent conductive oxide (SnO₂)/organic layers/aluminum thin film sandwich structures were obtained by vacuum evaporation. The organic component was either a thin carbazole film or a bilayer. In that case, the carbazole film was deposited onto a thin insulating polymer film. The polymer used was the poly(tetrabromo‐p‐phenyleneselenide) (PBrPDSe). Photoluminescence measurements have shown that the carbazole thin films emit blue light. (I‐V) measurements have shown that the structures exhibit diode characteristics. The forward direction is obtained when the transparent conductive oxide (TCO) is positively biased. However, the reproducibility of the results obtained with a single carbazole layer is poor. It appears that the stability of the sample is improved when a thin PBrPDSe film (40 nm) is introduced between the carbazole and the SnO₂. The polymer film avoids the short circuit effect. In that case, the turn‐on voltage of the diode is about 3 V, when the thickness of the carbazole film is around 250 nm and the electroluminescence appears at a voltage of about 5 V. It is shown that the thermionic effect cannot be used to explain the I‐V characteristics, which are interpreted with the help of the Fowler–Nordheim tunnel effect. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2042–2055, 2001     

Orthogonal Translation Meets Electron Transfer: In Vivo Labeling of Cytochrome c for Probing Local Electric Fields

Cytochrome c (cyt c), a redox protein involved in diverse fundamental biological processes, is among the most traditional model proteins for analyzing biological electron transfer and protein dynamics both in solution and at membranes. Studying the role of electric fields in energy transduction mediated by cyt c relies upon appropriate reporter groups. Up to now these had to be introduced into cyt c by in vitro chemical modification. Here, we have overcome this restriction by incorporating the noncanonical amino acid p‐cyanophenylalanine (pCNF) into cyt c in vivo. UV and CD spectroscopy indicate preservation of the overall protein fold, stability, and heme coordination, whereas a small shift of the redox potential was observed by cyclic voltammetry. The C≡N stretching mode of the incorporated pCNF detected in the IR spectra reveals a surprising difference, which is related to the oxidation state of the heme iron, thus indicating high sensitivity to changes in the electrostatics of cyt c.     

Olive oil consumption and reduced incidence of hypertension: The SUN study

Olive oil, a major component of the Mediterranean diet, has been associated in some small clinical trials and cross-sectional studies with a reduction in blood pressure. The objective of this study was to assess the association of olive oil consumption with the incidence of hypertension in an epidemiologic cohort, the Seguimiento Universidad de Navarra (SUN) study. The SUN Project is a prospective cohort study whose members are all university graduates. The recruitment and follow-up of participants is made using mailed questionnaires. Diet was assessed using a semiquantitative food frequency questionnaire previously validated in Spain, with 136 items. Outcomes of interest were newly diagnosed cases of hypertension, as reported by participants in the follow-up questionnaires. Logistic regression models were fit to assess the risk of hypertension associated with olive oil consumption. For the present analysis, we have taken in consideration the first 6,863 participants, with at least 2 yr of follow-up. After a median follow-up time of 28.5 mon, the cumulative incidence of hypereension was 4.7% in men and 1.7% in women. A lower risk of hypertension was observed among participants with a higher olive oil consumption at baseline, but the results were not statistically significant (P=0.13 for the linear trend test in the multivariate model). However, among men, the adjusted odds ratios (OR) (95% confidence intervals) of hypertension for the second to fifth quintiles of olive oil consumption, compared with the first quintile, were 0.55 (0.28–1.10), 0.75 (0.39–1.43), 0.32 (0.15–0.70), and 0.46 (0.23–0.94), respectively (P=0.02 for linear trend). No association was found between olive oil consumption and the risk of hypertension among women. In conclusion, in a Mediterranean population, we found olive oil consumption to be associated with a reduced risk of hypertension only among men. The lack of association observed among women might be attributed to the overall lower incidence of hypertension found among females and the resulting lower statistical power.     

Comparison of two size-differentiating air samplers for detecting airborne swine viruses under experimental conditions

Detection and quantification of dilute viral aerosols, as encountered outside animal housing facilities, requires methods that are able to detect small numbers of viruses in large volumes of air. This study compared the performance of two size-differentiating cascade impactors; an Andersen 8-stage (ACI; 28.3 L/min) and a high volume Tisch (TCI; 1,133 L/min) to assess sampling efficiency for detecting porcine reproductive and respiratory syndrome virus (PRRSV) and influenza A virus (IAV). Samples of particles sorted by aerodynamic diameter were analyzed by quantitative polymerase chain reaction (qPCR) and collection efficiency was assessed by particle size. Collection media (minimum essential medium [MEM] and beef extract [BE]), elution technique (active versus passive), and sampling times (10, 20, and 30 min) were variables assessed for the TCI sampler. Extraction efficiency was 35% higher with BE as compared to that of MEM (p = 0.0007); active extraction technique was 19% more efficient than the passive technique (p = 0.03); time of sampling did not significantly affect the amount of virus recovered. The ACI sampler was more efficient in detecting both viruses from small and medium sized airborne particles (≤3 μm) as compared to the TCI sampler (p < 0.001). The latter sampler, however, was more efficient at IAV detection from large airborne particles (>3 μm) (p = 0.0025) indicating the potential of this sampler in detecting the presence of small amounts of viruses in aerosols under field conditions.

© 2017 American Association for Aerosol Research     

Thermo‐hydraulic analysis of refinery heat exchangers undergoing fouling

A complete, systematic approach is presented for the analysis and characterization of fouling and cleaning in refinery heat exchangers. Bringing together advanced thermo‐hydraulic dynamic models, some new formulations, and a method for dynamic analysis of plant data, it allows: extracting significant information from the data; evaluating the fouling state of the units based on thermal measurements and pressure drops, if available; identifying the range of deposit conductivity leading to realistic pressure drops, if pressure measurements are unavailable; estimating key fouling and ageing parameters; estimating the effectiveness of cleaning and surface conditions after a clean; and predicting thermal and hydraulic performance with good accuracy for other periods/exchangers operating in similar conditions. An industrial case study demonstrates the performance prediction in seamless simulations that include partial and total cleanings for over 1000 days operation. The risks of using thermal effects alone and the significant advantages of including pressure drop measurements are highlighted. © 2016 American Institute of Chemical Engineers AIChE J, 63: 984–1001, 2017     

Influence of ionic liquid composition on the stability of polyvinyl chloride‐based ionic liquid inclusion membranes in aqueous solution

Membrane technology has gained significant importance with the incorporation of ionic liquids into their structure. This work shows the influence of ionic liquid composition on the stability of PVC‐based polymer ionic liquid inclusion membranes (PILIMs) in aqueous solution. Among the ILs investigated, those membranes which contain between 20 and 30%_w/w of the least soluble, [OMIM⁺][PF₆^?] and [OMIM⁺][Ntf₂^?], exhibit losses of IL lower than 10%. For both ILs, the amount immobilized was maximum for the membranes with 30%_w/w of IL (0.0838 and 0.0832 g, respectively). On the contrary, the ionic liquid loss increases as its solubility in water increase, reaching 99.52% when PILIMs are prepared with 70%_w/w of [OMIM⁺][BF₄^?]. The results demonstrate that the stability of PILIMs depends on the solubility of the IL in the surrounding phase and the specific interaction between the IL and the polymeric support for PVC‐to‐IL ratios higher than 30%_w/w. © 2016 American Institute of Chemical Engineers AIChE J, 63: 770–780, 2017     

Creation of a functional polysiloxane layer on the surface of magnetic nanoparticles using the sol-gel method

The developed methods using tetraethoxysilane and trifunctional silanes were applied to obtain Fe₃O₄ magnetic particles that contain amino groups with compositions of ≡Si(CH₂)₃NH₂, ≡Si(CH₂)₃NH(CH₂)₂NH₂, and [≡Si(CH₂)₃]₂NH. The XRD data show that the nuclei of nanoparticles in the obtained materials preserve the structure of the primary carrier, namely, that of Fe₃O₄ magnetite. The thermograms show a high thermal stability of the applied surface layers, i.e., their destruction was found to start at temperature above 250°C. The DRIFT spectra indicate the formation of the silica bond framework in the surface layers of nanoparticles and also the existence of hydrogen bonds between amino groups and silanol groups with the participation of water molecules aided. All of the obtained materials exhibit magnetic properties and offer promising application in medicine.