Secondary Organic Material Produced by the Dark Ozonolysis of α-Pinene Minimally Affects the Deliquescence and Efflorescence of Ammonium Sulfate

The hygroscopic phase transitions and growth factors of mixed particles having as components ammonium sulfate and secondary organic material (SOM) were measured. The SOM was generated by the dark ozonolysis of α-pinene, and organic particle mass concentrations of 1.63 and 12.2 μg m^?3 were studied. The hygroscopic properties were investigated using a 1×3 tandem differential mobility analyzer (1×3-TDMA). The 1×3-TDMA takes advantage of the hysteresis between solid-to-aqueous and aqueous-to-solid phase transitions to determine the efflorescence and deliquescence relative humidities (ERH and DRH, respectively) of materials. Overall, the influence of the SOM produced by the dark ozonolysis of α-pinene on the ERH and DRH of ammonium sulfate was small, shifting for example the DRH from 80% for pure ammonium sulfate to 77% for organic volume fractions of 0.96. The ERH likewise shifted by only a small amount across this composition range, specifically from 31 to 29%. The SOM produced at the lower organic particle mass concentrations shifted ERH and DRH even less, indicating an influence of SOM chemical composition on phase transitions. The hygroscopic growth factors of the mixed particles were adequately modeled across the range of studied RH (50 to 83%) using volume-averaged growth factors of the pure materials. The results for ERH, DRH, and the growth factors were all consistent with a model of phase separation between the inorganic and organic phases in individual particles, at least for the studied RH values (<83%) and for SOM prepared by α-pinene ozonolysis.     

Effect of the OH Radical Scavenger Hydrogen Peroxide on Secondary Organic Aerosol Formation from α-Pinene Ozonolysis

Hydrogen peroxide (HOOH) is a potentially valuable hydroxyl radical (OH) scavenger in secondary organic aerosol experiments focused on ozonolysis yields. Here, we present results for α-pinene ozonolysis. The OH scavenging produces solely HO₂ radicals and the resulting high [HO₂]/[RO₂] ratio causes an increase in aerosol formation from α-pinene ozonolysis, compared to experiments performed with butanol OH scavengers. The majority of the increase comes in the 100 μg m^?3 volatility range, suggesting that instead of more volatile products formed under higher RO₂ conditions, less volatile, multifunctional hydroperoxides form under the high-HO₂ conditions here. This dependence on the [HO₂]/[RO₂] ratio can be parameterized in a similar fashion to the way high- and low-NO _x yields are currently treated in models.     

Dependence of Real Refractive Indices on O:C,H:C and Mass Fragments of Secondary Organic Aerosol Generated from Ozonolysis and Photooxidation of Limonene and α-Pinene

The refractive index is a fundamental property controlling aerosol optical properties. Secondary organic aerosols have variable refractive indices, presumably reflecting variations in their chemical composition. Here, we investigate the real refractive indices (m_r) and chemical composition of secondary organic aerosols (SOA) generated from the oxidation of α-pinene and limonene with ozone and NO_x/sunlight at different HC/NO_x ratios. Refractive indices were retrieved from polar nephelometer measurements using parallel and perpendicular polarized 532-nm light. Particle chemical composition was monitored with a high-resolution time-of-flight aerosol mass spectrometer (HR-Tof-AMS). For photochemically generated SOA, the values of refractive indices are consistent with prior results, and ranged from about 1.34 to 1.55 for limonene and from 1.44 to 1.47 for α-pinene, generally increasing as the particles grew. While AMS fragments are strongly correlated to the refractive index for each type of SOA, the relationships are in most cases quite different for different SOA types. Consistent with its wide range of refractive index, limonene SOA shows larger variations compared to α-pinene SOA for most parameters measured with the AMS, including H:C, O:C, f₄₃ (m/z 43/organic), f_C4H7 ⁺, and others. Refractive indices for α-pinene ozonolysis SOA also fell in narrow ranges; 1.43–1.45 and 1.46–1.53 for particles generated at 19–22 and 23–29°C, respectively, with corresponding small changes of f₄₃ and H:C ratio and other parameters. Overall, H:C ratio, m/z 43 and 55 (C₂H₃O⁺, C₄H₇ ⁺) were the best correlated with refractive index for all aerosol types investigated. The relationships between m_r and most fragments support the notion that increasing condensation of less oxygenated semivolatile species (with a possible role for a concomitant decrease in low refractive index water) is responsible for the increasing m_rs observed as the experiments progress. However, the possibility that oligomerization reactions play a role cannot be ruled out.     

Effect of α-, β-, γ-, and δ-Tocotrienol on the Oxidative Stability of Lard

Despite the structural similarity of tocopherols, the antioxidative activities of tocotrienol homologues have not been studied often. In this study, the antioxidant activities of α-, β-, γ-, and δ-tocotrienols at various concentrations from 100 to 1,000 ppm in lard were evaluated. Headspace oxygen content of the lard without tocotrienol decreased from 21.1 to 10.7 % and the peroxide value increased from 0.4 to 33.4 mequiv/kg after 7 days of storage at 55 °C in the dark. α-Tocotrienol at 100 ppm and β-tocotrienol at 100 and 200 ppm effectively improved the oxidative stability of lard; however, the antioxidative activities of α- and β-tocotrienol reduced as the concentration increased to 1,000 ppm. The γ- and δ-tocotrienols improved the oxidation stability of lard and the effectiveness was essentially same at all concentrations (p > 0.05). The antioxidative activities of tocotrienols in the autoxidation of lard increased in the order of α-, β-, γ-, and δ-tocotrienols. The activities of tocotrienols in lard were different depending on the type of homologues and concentrations.     

An Appreciation of Organic Solid-State Chemistry and Challenges in the Field of “Molecules,Materials, Medicines”

Over many years, much of what has motivated a considerable amount of research in the general area of organic solid-state chemistry concerns an understanding of how molecular packing within an organic solid affects its physical and chemical properties. Whilst the motivation for this understanding may have changed over time, the fundamental issues remain the same. An understanding of the effect of crystal attributes (e.g., polymorph, habit and particle size) on chemical, physical, photophysical and electronic properties is still vital to the development of organic solids with optimised properties. While progress has been made in analytical skills (including sophisticated developments in instrumentation), along with major developments in computational techniques, there are still many challenges. This paper, with a primary focus on pharmaceuticals, provides a brief, and not comprehensive, personal overview of the progress that has been made and has yet to be made. Amongst the chemists and crystallographers who have contributed significantly to the subject is Jack Dunitz and some of his seminal papers appear in several of the issues discussed.     

Effect of α-, β-, γ-, and δ-Tocotrienol on the Singlet Oxygen Oxidation of Lard

The impacts of four different types of tocotrienol homologues on the singlet oxygen oxidation of lard were evaluated by measuring the headspace oxygen content and the peroxide value. Singlet oxygen oxidation of lard was induced by chlorophyll photosensitization. Samples of 0.100, 0.250, and 0.400 M lard in methylene chloride containing chlorophyll and α‐, β‐, γ‐, or δ‐tocotrienol were prepared and stored under light at 3,000 lux for 4 h. All tocotrienol homologues at 1.20 mM significantly prevented the singlet oxygen oxidation of lard. Chlorophyll under light produced singlet oxygen at 1.09 μmol oxygen/mL headspace/h. A steady state kinetic study showed that tocotrienols reduced the singlet oxygen oxidation of lard by quenching the singlet oxygen. Singlet oxygen reacted with lard at 6.50 × 10⁴M^?1 s^?1. α‐, β‐, γ‐, and δ‐tocotrienol quenched singlet oxygen with the rate of 2.16, 1.99, 2.05, and 0.800 × 10⁷M^?1 s^?1, respectively. Among them, α‐tocotrienol significantly prevented singlet oxygen oxidation of lard.     

Heteropolyacid-catalyzed dimerization of α-methylstyrene; on the efficiency and selectivity dependence

In the presence of catalytic amounts of a Keggin (H₃PW₁₂O₄₀), Wells–Dawson (H₆P₂W₁₈O₆₂) or Preyssler (H₁₄NaP₅W₃₀O₁₁₀) heteropolyacid, α-methylstyrene (1) leads to dimers. The efficiency and the selectivity toward 2,4-diphenyl-4-methyl-1-pentene (2), 2,4-diphenyl-4-methyl-2-pentene (3) and 1,1,3-trimethyl-3-phenylindan (4) depend on the reaction temperature and the nature of both the catalyst and the solvent. Thus, 2, 3 and 4 can be produced in 45%, 50% and 97% yields, respectively.     

Similarities in STXM-NEXAFS Spectra of Atmospheric Particles and Secondary Organic Aerosol Generated from Glyoxal, α-Pinene,Isoprene, 1,2,4-Trimethylbenzene,and d-Limonene

The organic functional group composition of particles produced in laboratory “smog” chambers were characterized by scanning transmission X-ray microscopy (STXM) with near-edge X-ray absorption fine structure (NEXAFS) spectroscopy and characteristic spectral signatures for secondary organic aerosol (SOA) were identified. The main objective of this study is to compare the single particle functional group composition of SOA formed from five precursors (glyoxal, α-pinene, isoprene, 1,2,4-trimethylbenzene, and d-limonene) to the composition of ambient particles from multiple field campaigns. This has implications for understanding the potential contributions of particles similar to those produced in SOA chambers to ambient compositions during those campaigns. Glyoxal uptake studies showed absorption from mainly alkyl, carbon-nitrogen (C-N), and carboxylic carbonyl groups. The SOA formed from the photooxidation of α-pinene (with and without isoprene) showed stronger absorptions for alkyl and carbonyl groups than the SOA formed from glyoxal. The mass ratio of carbonyl to acid group was larger in α-pinene-only experiments relative to the mixed α-pinene-isoprene experiments. Of 338 single-particle spectra available from aerosol sampling at six field campaigns, 114 particles had spectral features that were considered similar to the chamber-SOA particles: MILAGRO-2006 (9 particles), VOCALS-2008 (41 particles), Whistler-2008 (22 particles), Scripps Pier-2009 (8 particles), Bakersfield-2010 (24 particles), and Whistler-2010 (10 particles). These similarities with chamber-generated SOA provide spectroscopic evidence of chemically similar SOA products from these precursors in ambient particles.

Copyright 2013 American Association for Aerosol Research     

Influence of nitrogen overpressure on the nitridation,densification and formation of β-SiAlONs produced by silicothermal reduction

β-SiAlON materials (with z = 1) with 2 mol% DyAG have been synthesised by silicothermal reduction under different nitrogen pressures. The possibility of rapidly nitriding silicon and forming the SiAlON phase has been investigated through its reaction sequence of formation under different pressures. β-SiAlONs were fully nitrided (degree of nitridation greater than 93%) and formed after a 1-h hold at 1400 °C, or after a straight ramp to 1500 °C under 0.7 MPa of nitrogen. This was not achievable under static nitrogen at atmospheric pressure where the degree of nitridation was only 43% and β-SiAlON phase represented only about 60% of the crystalline phase assemblage at the same temperature. The formation of β-SiAlON depended on the formation of Si₃N₄ whose reaction rate was enhanced by nitrogen overpressures.     

Influence of Prolonged Deep-Frying Using Various Oils on Volatile Compounds Formation of French Fries Using GC–MS,GC-O,and Sensory Evaluation

Flavor is a decisive sensory characteristic to determine the popularity of French fries (FF). To investigate the effect of prolonged deep-frying using various oils on volatiles formation of FF, the FF were prepared in the palm oil (PO), soybean oil (SO), and high-oleic rapeseed oil (RO) for 24 hours intermittent frying. The effect of oil types was found to be more significant than the frying time on the volatiles of FF indicated from the clusters of the fried FF by chemometric analysis. A total of 26 key aroma-active compounds were identified by aroma extract dilution analysis, in which aldehydes were predominant. The FF fried in SO revealed higher desirable aroma compounds, i.e., (E, E)-2,4-decadienal and it increased to maximum value at 12 hours, and left the deep-fried odor in FF. Meanwhile, a significant increase in metallic off-flavor was observed in FF fried in SO and PO at 20 hours, indicating that oil quality reduction resulted in FF with unappealing flavor. The above results showed that frying process had an optimum frying window (approximately 4–16 hours with total polar compounds content below 22.2%), and the French fries prepared in this period obtained higher flavor scores. The study will provide insights into the effect of oil types and oxidation degree on obtaining the ideal flavors for fried food.     

Na(+), K(+)-ATPase Subunit Composition in a Human Chondrocyte Cell Line; Evidence for the Presence of α1, α3, β1, β2 and β3 Isoforms

Membrane transport systems participate in fundamental activities such as cell cycle control, proliferation, survival, volume regulation, pH maintenance and regulation of extracellular matrix synthesis. Multiple isoforms of Na(+), K(+)-ATPase are expressed in primary chondrocytes. Some of these isoforms have previously been reported to be expressed exclusively in electrically excitable cells (i.e., cardiomyocytes and neurons). Studying the distribution of Na(+), K(+)-ATPase isoforms in chondrocytes makes it possible to document the diversity of isozyme pairing and to clarify issues concerning Na(+), K(+)-ATPase isoform abundance and the physiological relevance of their expression. In this study, we investigated the expression of Na(+), K(+)-ATPase in a human chondrocyte cell line (C-20/A4) using a combination of immunological and biochemical techniques. A panel of well-characterized antibodies revealed abundant expression of the α1, β1 and β2 isoforms. Western blot analysis of plasma membranes confirmed the above findings. Na(+), K(+)-ATPase consists of multiple isozyme variants that endow chondrocytes with additional homeostatic control capabilities. In terms of Na(+), K(+)-ATPase expression, the C-20/A4 cell line is phenotypically similar to primary and in situ chondrocytes. However, unlike freshly isolated chondrocytes, C-20/A4 cells are an easily accessible and convenient in vitro model for the study of Na(+), K(+)-ATPase expression and regulation in chondrocytes.     

Study on the Expression and Clinical Significances of Lewis y Antigen and Integrin αv, β3 in Epithelial Ovarian Tumors

Objective

To detect the expression and clinical significances of Lewis y antigen and integrin αv, β3 in epithelial ovarian tumors, and to explore the expression correlation between Lewis y antigen and integrin αv, β3.

Methods

Immunohistochemical staining was performed in 95 cases of epithelial ovarian cancer, 37 cases of borderline tumors, 20 cases of benign tumors, and 20 cases of normal ovarian tissue, for the detection of Lewis y antigen and integrin αv, β3 expressions, and to analyze the relationship between Lewis y antigen and integrin, and the relationship between clinical and pathological parameters of ovarian cancer. In addition, immunofluorescence double labeling was utilized to detect the expression correlation between Lewis y antigen and integrin αv, β3 in ovarian cancer.

Results

In epithelial ovarian tumors, the expression rate of Lewis y antigen was 81.05%, significantly higher than that of borderline (51.53%) (P < 0.05) and benign (25%) (P < 0.01) tumors, and normal ovarian tissues (0) (P < 0.01). The expression rate of integrin αv, β3 in malignant epithelial ovarian tumors was 78.95% and 82.11%, respectively, significantly higher than that of the borderline (45.94%, 40.54%) (both P < 0.05), benign group (10.00%, 15.00%) (both P < 0.01) and normal ovary group (5%, 15%) (both P < 0.01).

Conclusions

Lewis y and integrins αv, β3 are relevant to pelvic and abdominal diffusion and metastasis of ovarian cancer cells, suggesting that these two molecules mediate a boosting function for tumor metastasis.     

Synthesis and Characterisation of PrMn<Subscript>1−X</Subscript>B<Subscript>X</Subscript>O<Subscript>3</Subscript> (B = Fe,Ni) as Catalysts for Oxidation of Volatile Organic Compounds

PrMn_1?XB_XO₃ (B?=?Fe, Ni, x?=?0.2, 0.4, 0.6, 0.8) perovskites were synthesised by co-precipitation and citrate precursor sol–gel method (CPSG). X-ray diffraction patterns indicate improved crystalline nature of materials synthesised by CPSG method. BET surface area values were highest for PrMn_0.4Fe_0.6O₃ (14.25 m²/g) and PrMn_0.6Ni_0.4O₃ (26.61 m²/g) and morphological analysis by scanning electron microscopy revealed porous nature of materials when synthesised by sol gel method. Particle size derived from transmission electron microscopy was smallest for PrMn_1?XNi_XO₃ (CPSG) series (20–120nm). X-ray photoelectron spectroscopy spectra suggest surface enrichment of Pr³⁺ ions in PrMn_0.4Fe_0.6O₃ and PrMn_0.6Ni_0.4O₃ for perovskites prepared by citrate precursor method. Catalytic oxidation of volatile organic compound (VOC) was carried out over PrMn_0.4Fe_0.6O₃ and PrMn_0.6Ni_0.4O₃. Under the reaction conditions (VOC concentration?=?1 vol%, flow rate 150 ml/min) the catalysts gave a conversion efficiency of 82% and 94% for PrMn_0.4Fe_0.6O₃ and PrMn_0.6Ni_0.4O₃ respectively. The perovskite materials are therefore potential catalysts for the oxidation of VOC.     

Effects of solid content on the phase assemblages,mechanical and dielectric properties of porous α-SiAlON ceramics fabricated by freeze casting

Porous Y-α-SiAlON ceramics were prepared by freezing camphene-based suspensions at 0 °C and subsequently sintering at 1900 °C for 1 h. The effects of solid loading content in the suspensions on porosities and formation of α-SiAlON as well as mechanical and dielectric properties of the porous ceramics were investigated. An XRD analysis performed on sintered samples indicated that the α-SiAlON did not fully form in the sample with initial solid loading content of 10 vol%, due to the high porosity of 90 vol% and interconnected pore of the green body. With the increase of initial solid loading content from 10 vol% to 30 vol%, the porosity decreased from 62.3% to 23.1% and the average pore size decreased from 19 μm to 8 μm. As a result, the flexural strength increased significantly from 72.4 MPa to 190.2 MPa, fracture toughness increased from 1.20 MPa m^1/2 to 3.48 MPa m^1/2, as well as the dielectric constant increased from 3.3 to 6.3. The dielectric loss (tan δ) of obtained material varied between 1.4×10^?2 and 2.8×10^?2, which did not depend on the porosity of samples.     

Effects of the initial α-SiC content on the microstructure, mechanical properties, and permeability of macroporous silicon carbide ceramics

By using α- and/or β-SiC staring powders, the effects of the initial α-phase content on the microstructure, mechanical properties, and permeability of macroporous SiC ceramics were investigated. When β-SiC powder or a mixture of α/β powders containing a small amount (≤10%) of α-SiC powder was used, the microstructure consisted of large platelet grains. In contrast, when using α-SiC powder or α/β powders containing a large amount (>10%) of α powders, the microstructure consisted of small equiaxed grains. The development of large α-SiC platelet grains in the microstructure did not result in any improvement of the flexural strength of the macroporous SiC ceramics because of the accompanying pore growth and grain growth. The growth of the platelet-SiC grains was beneficial in increasing the gas permeability of the macroporous SiC ceramics from 4.12 × 10⁻¹³ m² for macroporous SiC with an equiaxed microstructure to 1.89 × 10⁻¹² m² for macroporous SiC ceramics with large platelet grains.     

The Effects of a “Palm Oil” Faiiy Acid Additive and a Silane Coupling Agent on the Curing Characteristics and Vulcanizate Properties of Silica-Filled Natural Rubber Compounds

Comparison study on effects of a “palm oil” fatty acid additive (POFA) and a silane coupling agent on the curing characteristics and vulcan-izates properties of silica-filled natural rubber were studied. Compared to the control compound, the incorporation of both ingredients enhances the cure rate and cure state of the rubber compounds. Both ingredients were found to be effective in reducing the viscosity of the rubber compounds. Swelling measurement and scanning electron microscopy studies indicate that both ingredients increase the cross-link density, improve filler dispersion, and, consequently, enhance the vulcanizate properties.     

The Influence of pH on the Hydrolysis Process of γ-Methacryloxypropyltrimethoxysilane,Analyzed by FT-IR,and the Silanization of Electrogalvanized Steel

Silanes are commonly used as coupling agents to enhance the adhesion between polymeric and inorganic materials. Once silane hydrolysis has taken place, the condensation of the silane on the substrate surface should follow. Optimum hydrolysis conditions will depend on the type of silane and the process conditions of the solution. The pH is particularly important as it has a significant effect on the hydrolysis process. This paper deals with the hydrolysis process of 1 vol% γ-methacryloxypropyltrimethoxysilane (MPS) in aqueous solution at different pHs (2, 4, 6, 8 and 10). Because the hydrolysis rate is a function of pH, hydrolysis times, ranging from 2 min to 48 h, were studied. Fourier transform infrared spectroscopy was used to evaluate the chemical modifications produced by changing the hydrolysis time. The disappearance of the infrared band due to the Si–O–C groups and the appearance of the bands due to the Si–OH bonds were studied. It was shown that longer times were necessary for complete hydrolysis, under almost neutral pH conditions. On the other hand, the Zn-electrocoated steel was silanized with MPS under an optimum pH and the hydrolysis time conditions and the resulting surfaces were analysed by Reflection–Absorption Infrared Reflectance Spectroscopy.     

Dose effect of α-linolenic acid on PUFA conversion,bioavailability, and storage in the hamster

If an increased consumption of α-linolenic acid (ALA) is to be promoted in parallel with that of n−3 long-chain-rich food, it is necessary to consider to what extent dietary ALA can be absorbed, transported, stored, and converted into long-chain derivatives. We investigated these processes in male hamsters, over a broad range of supply as linseed oil (0.37, 3.5, 6.9, and 14.6% energy). Linoleic acid (LA) was kept constant (8.5% energy), and the LA/ALA ratio was varied from 22.5 to 0.6. The apparent absorption of individual FA was very high (>96%), and that of ALA remained almost maximum even at the largest supply (99.5%). The capacity for ALA transport and storage had no limitation over the chosen range of dietary intake. Indeed, ALA intake was significantly correlated with ALA level not only in cholesteryl esters (from 0.3 to 9.7% of total FA) but also in plasma phospholipids and red blood cells (RBC), which makes blood components extremely reliable as biomarkers of ALA consumption. Similarly, ALA storage in adipose tissue increased from 0.85 to 14% of total FA and was highly correlated with ALA intake. As for bioconversion, dietary ALA failed to increase 22∶6n−3, decreased 20∶4n−6, and efficiently increased 20∶5n−3 (EPA) in RBC and cardiomyocytes. EPA accumulation did not tend to plateau, in accordance with identical activities of Δ5- and Δ6-desaturases in all groups. Dietary supply of ALA was therefore a very efficient means of improving the 20∶4n−6 to 20∶5n−3 balance.