A Maternal High Fat Diet Has Long‐Lasting Effects on Skeletal Muscle Lipid and PLIN Protein Content in Rat Offspring at Young Adulthood

A maternal high fat diet (HFD) can have adverse effects on skeletal muscle development. Skeletal muscle PLIN proteins (PLIN2, 3 and 5) are thought to play critical roles in lipid metabolism, however effects of HFD on PLIN and lipases (HSL, ATGL, CGI‐58) in mothers as well as their offspring have yet to be investigated. The primary objective of this study was to determine whether maternal HFD would influence skeletal muscle lipase and PLIN protein content in offspring at weaning (19d) and young adulthood (3mo). Female rats (28d old, n = 9/group) were fed control (CON, AIN93G, 7 % soybean oil) or HFD (AIN93G, 20 % lard) for 10 weeks prior to mating and throughout pregnancy and lactation. All offspring were weaned to CON [n = 18/group, 1 female and 1 male pup per litter were studied at weaning (19d) and 3mo of age]. There was no effect of sex for the main outcomes measured in plantaris, therefore male and female data was combined. Maternal HFD resulted in higher triacylglycerol content in pups at 3mo (p < 0.05), as well as in the dams (p = 0.015). Maternal HFD resulted in higher PLIN5 content in pups at weaning and 3mo (p = 0.05). PLIN2 and PLIN5 content decreased at 3mo versus weaning (p < 0.001). HFD dams had a higher PLIN3 content (p = 0.016). Diet had no effect on ATGL, CGI‐58, or HSL content. In conclusion, exposure to a maternal HFD resulted in higher skeletal muscle lipid and PLIN5 content in plantaris of offspring through to young adulthood.     

A crossover‐UNIQUAC model for critical and noncritical LLE calculations

A new model, named the crossover‐UNIQUAC model, has been proposed based on the crossover procedure for predicting constant‐pressure liquid–liquid equilibria (LLE). In this manner, critical fluctuations were incorporated into the classical UNIQUAC equation. Coexistence curves were estimated for systems having a diverse range of asymmetries. These systems included the LLE of five different mixtures, composed of nitrobenzene with one of the members of the alkane homologous family (either pentane, octane, decane, dodecane, or tetradecane), as well as an extra system having a different chemical nature, namely the mixture of n‐perfluorohexane and hexane, to further check the validity of the proposed approach. Using these nonideal mixtures, the validity of the new model was investigated within wide ranges, covering near‐critical to regions falling far away from the critical point. The graphical trends, as well as the quantitative comparison with experimental data indicated the good agreement of the proposed model results with the experimental data. A maximum AARD% value of 3.97% was obtained in calculating molar compositions by the proposed model for such challenging systems covering noncritical, as well as critical regions. In addition, to show the strength of the proposed crossover approach to describe properties other than LLE, molar heat capacities were investigated for the system of nitrobenzene + dodecane. © 2015 American Institute of Chemical Engineers AIChE J, 61: 3094–3103, 2015     

Quiescent crystallization of poly(lactic acid) studied by optical microscopy and light‐scattering techniques

The crystallization behavior of poly(lactic acid) (PLA) has been studied extensively, and this has resulted in different reported values for the nucleation densities (Ns) and crystal growth rates (Gs) for similar grades. These inconsistencies may be magnified when they are used in subsequent modeling studies. Therefore, the quiescent crystallization behaviors of three PLA grades were studied with polarized optical microscopy and small‐angle light‐scattering experiments. The Gs and Ns were determined at several isothermal crystallization temperatures with a device that provided near‐instantaneous cooling to the isothermal crystallization temperature. Two growth rate regimes, which were attributed to α and α′ crystallization with a transition around 120 °C, were observed. Avrami analysis revealed that the poly(l ‐lactic acid) homopolymer crystal growth was three‐dimensional and was unaffected by the presence of stereocomplex PLA. The PLA copolymer crystals had a transition from an initial sheaflike conformation to three‐dimensional growth. Furthermore, the lamellar twisting of the homopolymer was observed at the isothermal crystallization temperature around 144 °C. These findings can be used for future modeling studies to predict material behavior in various industrial processes. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44566.     

Fiber‐draw‐induced elongation and break‐up of particles inside the core of a silica‐based optical fiber

Particles in the core of optical fibers are widely studied to tailor or to improve optical properties. The analysis of nanoparticles embedded in silica‐based optical fiber allowed new observations of the evolution of amorphous particles during fiber drawing. Even at the nanoscale, competition between viscous stresses and surface tension on the particles induces elongation and even break‐up of particles during the process. Indeed, particles between 140 and 200 nm diameter inside the preform can break up in fragments with diameters down to 60 nm inside the drawn fiber. Break‐up of particles appears as a new “top‐down” strategy to produce small particles. These observations are promising for micro/nanostructured and multiphasic optical fibers.     

A Shelter to Protect a Passive Sampler for Coarse Particulate Matter,PM10 − 2.5

This work designed and tested a shelter to protect a passive sampler for measuring coarse particulate matter, PM _{10 ? 2.5} . The shelter protects the sampler from precipitation and reduces the effects of wind on the deposition of particles to its collection surface. Six shelters were tested in a wind tunnel at three wind speeds: 2, 8, and 24 km hr ^?1 . Shelter performance was expressed as the ratio of PM _{10 ? 2.5} measured with the passive samplers to that measured with a filter-based dichotomous sampler. For most shelters, the PM _{10 ? 2.5} ratio averaged across wind speeds was well above one (2.4 to 8.5) and was generally dependent on wind speed. However, the PM _{10 ? 2.5} ratio for one shelter, the Flat Plates shelter, was 1.04 with substantially less effect on particle deposition from wind speed. Eight week-long field tests were conducted to compare PM _{10 ? 2.5} measured with a passive sampler installed in a Flat Plates shelter to that measured with a collocated filter-based dichotomous sampler. In these tests, the mean PM _{10 ? 2.5} ratio was 1.29. The linear relationship between PM _{10 ? 2.5} measured passively to that measured with the filter-based sampler had a Pearson correlation coefficient of 0.97 and was not significantly affected by the addition of weekly mean wind speed (p = 0.35). Although temperature was significant in this regression model (p = 0.02), it only improved the relationship marginally. The passive sampler in a Flat Plates shelter offers an inexpensive means to assess ambient PM _{10 ? 2.5} without on-site measurement of wind speed.     

Evaluation of the Loading Characteristics of the EPA WINS PM2.5 Separator

The loading characteristics of the USEPA Well Impactor Ninety Six (WINS) PM_2.5 separator was an important design consideration during the separator's development. In recognition that all inertial separators eventually overload, the loading surface of the WINS was designed to be easily accessible, replaceable, and cleanable. Prior to promulgation of the method, the loading capacity of the WINS separator was evaluated by measuring its performance after repeated loading with laboratory-generated, high concentration, coarse-mode aerosol. For this purpose, a low flow rate loading wind tunnel was designed and constructed to artificially create coarse mode aerosols composed of Arizona Test Dust. This controlled test atmosphere was sampled by the PM_2.5 reference method sampling train, as specified in 40 CFR Part 50, Appendix L, at total aerosol mass concentrations averaging 332     

An improved accelerated weathering protocol to anticipate Florida exposure behavior of coatings

A new accelerated weathering protocol has been developed which closely replicates the performance of automotive and aerospace coating systems exposed in South Florida. IR spectroscopy was used to verify that the chemical composition changes that occurred during accelerated weathering in devices with a glass filter that produced a high fidelity reproduction of sunlight’s UV spectrum matched those that occurred during natural weathering. Gravimetric water absorption measurements were used to tune the volume of water absorption during accelerated weathering to match that which occurred during natural weathering in South Florida. The frequency of water exposure was then scaled to the appropriate UV dose. A variety of coating systems were used to verify the correlation between the physical failures observed in the accelerated weathering protocol and natural weathering in South Florida. The new accelerated weathering protocol correctly reproduced gloss loss, delamination, cracking, blistering, and good performance in a variety of diverse coating systems. For automotive basecoat/clearcoat paint systems, the new weathering protocol shows significant acceleration over both Florida and previous accelerated weathering tests. For monocoat aerospace systems, the new weathering protocol showed less acceleration than for automotive coatings, but was still an improvement over previous accelerated tests and was faster than Florida exposure.     

The Influence of Cooling Rate on the Specific Volume of Isotactic Poly(propylene) at Elevated Pressures

Summary: We used a custom designed dilatometer to measure quantitatively the time evolution of the specific volume of (semi‐crystalline) polymers for an unusual combined wide range of cooling rates and elevated pressures, covering processing conditions. For an isotactic poly(propylene), applying the Schneider rate equations for quiescent crystallization, experimental results are compared to numerical predictions. Average cooling rates imposed during crystallization of the material vary from 0.1 to 35 °C · s^?1 while pressures range from 20 to 60 MPa. The results show the well‐known profound influence of pressure and cooling rate on the specific volume. An increasing cooling rate shifts the crystallization temperature T_c towards lower temperatures, increases the final specific volume, and the transition due to crystallization is more gradual and widespread. For the highest cooling rate applied, the shift in T_c is as much as 30 °C, while the final specific volume increases up to 1.4%. Increasing pressure has an opposite effect on the shift in T_c, while the final specific volume, after pressure release, also increases. Finally, a comparison of numerical predictions with experimental data shows that the crystallization temperature T_c is consistently predicted too low, and that the predictions at high cooling rate are sensitive to (small) variations in model parameters.

Influence of cooling rate on the specific volume of iPP.     

Phase morphology of as-molded and annealed blends of polyarylate/copolyester

The phase morphology of injection molded blends of polyarylate (PAR) and a copolyester (PCTG-5445) was studied by transmission electron microscopy (TEM) and X-ray diffraction (XRD). The use of ultramicrotomy to prepare ? 50 nm thin section TEM specimens and solvent etching to dissolve the PAR phase revealed PCTG as the matrix phase in the as-molded state which crystallized into PCTG spherulites upon annealing. The most consistent morphological information vs. concentration of PCTG and the highest structural integrity of the PCTG spherulites was obtained from thin sections treated with a mixture of 75% methylene chloride as the solvent for the PAR and 25% 2-propanol as the nonreactive diluent. XRD results from the annealed PCTG/PAR blends show crystalline reflections of 0.59, 0.53, 0.46, 0.38, and 0.35 nm, which disappear into the amorphous background below 50% PCTG.     

Ozone Degradation Study of Novel Chain Extended Energetic Polymers Containing Carbon‐Carbon Double Bonds

A range of chemically modified energetic polymers has been synthesized. The structural modification involves the incorporation of a double bond into the polymeric binder which allows subsequent degradation of the material by ozonolysis thus providing an environmentally safe method for the disposal of munitions. This was achieved by reacting the energetic prepolymer, poly‐NIMMO, with a range of unsaturated diisocyanates where the double bond was incorporated into the cross‐linking i.e. “curing” agent. Firstly, poly‐NIMMO and cis‐1,4‐but‐2‐ene diol were reacted with hexamethylene diisocyanate. Secondly, three unsaturated diisocyanates (two novel) were prepared in situ from their corresponding diacyl azides and reacted with poly‐NIMMO. The three diisocyanates prepared were 1,4‐diphenoxy‐trans‐2‐butene‐diisocyanate, phenylene diacrylic di‐isocyanate, and trans‐2‐butene‐1,4‐diisocyanate. The latter has been reported previously^(1,2) although never isolated and characterized; however, this has been achieved successfully in this study. GPC of the chain extended polymers prepared by both methods showed the expected increase in molecular weight distribution. A corresponding decrease following ozonolysis occurred particularly with the polymers prepared from 1,4‐diphenoxy‐trans‐2‐butene‐diisocyanate and phenylene diacrylic diisocyanate.