Confounding Effects of Tamoxifen: Cautionary and Practical Considerations for the Use of Tamoxifen-Inducible Mouse Models in Atherosclerosis Research-Brief Report.

BACKGROUND: In recent years, fate-mapping lineage studies in mouse models have led to major advances in vascular biology by allowing investigators to track specific cell populations in vivo. One of the most frequently used lineage tracing approaches involves tamoxifen-inducible CreERT-LoxP systems. However, tamoxifen treatment can also promote effects independent of Cre recombinase activation, many of which have not been fully explored. METHODS: To elucidate off-target effects of tamoxifen, male and female mice were either unmanipulated or injected with tamoxifen or corn oil. All mice received PCSK9 (proprotein convertase subtilisin/kexin type 9)-AAV (adeno-associated virus) injections and a modified Western diet to induce hypercholesterolemia. After 2 weeks, serum cholesterol and liver morphology were assessed. To determine the duration of any tamoxifen effects in long-term atherosclerosis experiments, mice received either 12 days of tamoxifen at baseline or 12 days plus 2 sets of 5-day tamoxifen boosters; all mice received PCSK9-AAV injections and a modified Western diet to induce hypercholesterolemia. After 24 weeks, serum cholesterol and aortic sinus plaque burden were measured. RESULTS: After 2 weeks of atherogenic treatment, mice injected with tamoxifen demonstrated significantly reduced serum cholesterol levels compared with uninjected- or corn oil-treated mice. However, there were no differences in PCSK9-mediated knockdown of LDL (low-density lipoprotein) receptors between the groups. Additionally, tamoxifen-treated mice exhibited significantly increased hepatic lipid accumulation compared with the other groups. Finally, the effects of tamoxifen remained for at least 8 weeks after completion of injections, with mice demonstrating persistent decreased serum cholesterol and impaired atherosclerotic plaque formation. CONCLUSIONS: In this study, we establish that tamoxifen administration results in decreased serum cholesterol, decreased plaque formation, and increased hepatic lipid accumulation. These alterations represent significant confounding variables in atherosclerosis research, and we urge future investigators to take these findings into consideration when planning and executing their own atherosclerosis experiments.

Characterization of Corn Oil Using Fluorescence Spectroscopy.

In these studies, Fluorescence spectroscopy has been utilized for the characterization of pure and commercially available corn oil. The best excitation wavelength of 380 nm has been investigated, where maximum spectral information can be assessed. The emission spectra from pure and commercial corn oil samples disclosed that pure corn oil contained oleic acid, beta-carotenes, chlorophylls, isomers of vitamin E and traces of oxidized products which exhibit fluorescence at 406, 525, 675, 440 and 435/475 nm respectively. Whereas, commercial corn oils lack these valuable ingredients and only contain fats along with their primary and secondary oxidized products that emit a broad emission band centred at 440 nm. The study has also depicted that Fluorescence spectroscopy can even be used to select best quality corn oil among pure corn oil samples with different varieties and seed origins. In addition, the effect of temperature on the composition of pure and commercial corn oil samples have also been investigated by heating them at 100, 120,140, 160, 180 and 200 °C each sample for 30 min. This was done because corn oil is being used for cooking where it is generally heated up to 120 °C and for deep frying up to 180 °C. On heating, in pure corn oil, deterioration of Vitamin-E and beta-carotenes occurred with an increase in the oxidation products, whereas, in commercial oil samples, only the concentration of oxidation products increased. However, it was found that up to 140 °C, pure corn oil can be used safely for cooking purpose where it does not lose much of its valuable ingredients while in commercial corn oils, fat composition does not alter much up to 180 °C and after that oxidized products start to increase rapidly.

In statin-treated patients at high CV risk, adding omega-3 fatty acids vs. corn oil to usual care did not reduce MACE.

SOURCE CITATION: Nicholls SJ, Lincoff AM, Garcia M, et al. Effect of high-dose omega-3 fatty acids vs corn oil on major adverse cardiovascular events in patients at high cardiovascular risk: the STRENGTH randomized clinical trial. JAMA. 2020;324:2268-80. 33190147.

Lowering n-6/n-3 Ratio as an Important Dietary Intervention to Prevent LPS-Inducible Dyslipidemia and Hepatic Abnormalities in ob/ob Mice.

Obesity is closely associated with low-grade chronic and systemic inflammation and dyslipidemia, and the consumption of omega-3 polyunsaturated fatty acids (n-3 PUFAs) may modulate obesity-related disorders, such as inflammation and dyslipidemia. An emerging research question is to understand the dietary intervention strategy that is more important regarding n-3 PUFA consumption: (1) a lower ratio of n-6/n-3 PUFAs or (2) a higher amount of n-3 PUFAs consumption. To understand the desirable dietary intervention method of n-3 PUFAs consumption, we replaced lard from the experimental diets with either perilla oil (PO) or corn oil (CO) to have identical n-3 amounts in the experimental diets. PO had a lower n-6/n-3 ratio, whereas CO contained higher amounts of PUFAs; it inherently contained relatively lower n-3 but higher n-6 PUFAs than PO. After the 12-week dietary intervention in ob/ob mice, dyslipidemia was observed in the normal chow and CO-fed ob/ob mice; however, PO feeding increased the high density lipoprotein-cholesterol (HDL-C) level; further, not only did the HDL-C level increase, the low density lipoprotein-cholesterol (LDL-C) and triglyceride (TG) levels also decreased significantly after lipopolysaccharide (LPS) injection. Consequently, extra TG accumulated in the liver and white adipose tissue (WAT) of normal chow- or CO-fed ob/ob mice after LPS injection; however, PO consumption decreased serum TG accumulation in the liver and WAT. PUFAs replacement attenuated systemic inflammation induced by LPS injection by increasing anti-inflammatory cytokines but inhibiting pro-inflammatory cytokine production in the serum and WAT. PO further decreased hepatic inflammation and fibrosis in comparison with the ND and CO. Hepatic functional biomarkers (aspartate aminotransferase (AST) and alanine transaminase (ALT) levels) were also remarkably decreased in the PO group. In LPS-challenged ob/ob mice, PO and CO decreased adipocyte size and adipokine secretion, with a reduction in phosphorylation of MAPKs compared to the ND group. In addition, LPS-inducible endoplasmic reticulum (ER) and oxidative stress decreased with consumption of PUFAs. Taken together, PUFAs from PO and CO play a role in regulating obesity-related disorders. Moreover, PO, which possesses a lower ratio of n-6/n-3 PUFAs, remarkably alleviated metabolic dysfunction in LPS-induced ob/ob mice. Therefore, an interventional trial considering the ratio of n-6/n-3 PUFAs may be desirable for modulating metabolic complications, such as inflammatory responses and ER stress in the circulation, liver, and/or WAT.

Atazanavir-Concentrate Loaded Soft Gelatin Capsule for Enhanced Concentration in Plasma, Brain, Spleen, and Lymphatics.

This study investigates the development of atazanavir-concentrate loaded soft gelatin capsule for achieving enhanced atazanavir (ATV) concentration in plasma, brain, spleen, and lymphatics beneficial in the significant reduction of viral load in HIV infection. For this purpose, ATV-concentrate in the presence and absence of Soluplus with corn oil, oleic acid, tween 80, and propylene glycol was developed. The developed ATV-concentrate was found to have enhanced dispersibility with no signs of precipitation after dilution with simulated G.I fluid as evident from particle size (16.49±0.32 nm) and PDI (0.217±0.02) analysis. The rheological and molecular docking studies explainedthe reduction of viscosity of SuATV-C due to the intermolecular H-bond between ATV and Soluplus that helps to retard crystallization. The shell of the soft gelatin capsule retains its integrity when subjected to a folding endurance test on a texture analyzer depicting that the concentrate did not affect the integrity of the soft gelatin capsule shell. An ex vivo and in vivo pharmacokinetic study in rats revealed that the SuATV-C soft gelatin capsule (SuATV-C SGC) indicated 2.9 fold improvement in rate and extent of permeation and absorption than that of ATV-suspension. The tissue distribution study also exhibited higher drug concentration in the brain (2.5 fold), lymph nodes (2.7 fold), and spleen (1.2 fold) administered with SuATV-C SGC, revealing the overwhelming influence of Soluplus and corn oil. In a nutshell, these studies demonstrated that SuATV-C SGC seems to have the potential to deliver an anti-retroviral drug to the viral sanctuaries for the better management of HIV.

A comparative study on the effects of hemp seed oil versus four different UFA-rich seed oils' dietary supplementation on egg production performance, egg quality, and yolk fatty acids in laying hens.

This study compared the effects of hemp seed oil versus four different UFA-rich seed oils in the diet of laying hens on egg production, egg quality, and fatty acid profile of the yolk. Soybean oil (SBO), sunflower oil (SFO), corn oil (CO), canola oil (CAO), and hemp seed oil (HSO) were included in the hens' diets in equal proportions. A total of one hundred and twenty White Leghorn hens were allocated into five groups with 8 replicates, each with 3 hens. The trial lasted 84 days and data were collected on egg production, quality, and fatty acid profile of the yolk. The results showed that none of the incorporated seed oils affected egg production parameters and eggshell quality. However, hemp seed oil altered yolk colour values similarly to canola oil by increasing the L* value of the yolk whilst decreasing the a* value (P < 0.05). Hemp oil increased the PUFA content in the yolk, similar to soybean, corn, and sunflower oil, but unlike the latter, it also enriched the n-3 fatty acids in the yolk (P < 0.05). In conclusion, hemp seed oil can be safely used in the diet of chickens without negative effects on egg production and egg quality like other seed oils. Furthermore, hemp seed oil can improve the desirable fatty acid content in the yolk and has the potential to produce n-3-enriched eggs.

The effects of different high-fat (lard, soybean oil, corn oil or olive oil) diets supplemented with fructo-oligosaccharides on colonic alkaline phosphatase activity in rats.

PURPOSE: We recently reported that fermentable non-digestible carbohydrates including fructo-oligosaccharides (FOS) commonly elevate colonic alkaline phosphatase (ALP) activity and the expression of IAP-I, an ALP gene, in rats fed a high-fat (HF) diet, and also elevate gut mucins and modulate gut microbiota. This study aims to investigate whether dietary fat types influence the effect of FOS on colonic ALP activity and the luminal environment in HF-fed rats. METHODS: Male Sprague-Dawley rats were fed a diet containing 30% soybean oil, corn oil, olive oil or lard with or without 4% FOS for 2 weeks. Colon ALP activity, gene expression, and gut luminal variables including mucins and microbiota were measured. RESULTS: In the lard diet groups, dietary FOS significantly elevated colonic ALP activity and the expression of IAP-I. The elevating effect of FOS on colonic ALP activity was also observed in the olive oil diet groups, although here the IAP-I expression was not changed. However, the soybean oil and corn oil diet groups did not exhibit the elevating effect of FOS on colon ALP. Fecal ALP and mucins were significantly elevated by dietary FOS regardless of dietary fat types, and the effect of FOS was prominent in the lard diet groups. The number of Lactobacillus spp. observed in fecal matter was significantly increased by dietary FOS in the lard and olive oil diet groups, but not in the soybean oil and corn oil diets groups. CONCLUSION: This study suggests that dietary fat types may change the effect of FOS on the colonic luminal environment including the ALP activity in rats fed a high-fat diet.

Increased corn oil intake during an allergy sensitization period aggravates food allergy severity after oral allergen exposure.

Egg white (EW) allergy model mice underwent 15-day oral immunotherapy (OIT) using diets with different corn-oil content and 1% EW. After OIT, mortality following an oral food challenge in OIT groups was approximately 90%. However, in previous studies, mortality was 0%. This phenomenon is to be associated with increased corn-oil intake during allergy sensitization and allergen exposure for 2 weeks.

Resolvin D1 Prevents the Impairment in the Retention Memory and Hippocampal Damage in Rats Fed a Corn Oil-Based High Fat Diet by Upregulation of Nrf2 and Downregulation and Inactivation of p66Shc.

This study investigated the effect of a high-fat diet rich in corn oil (CO-HFD) on the memory retention and hippocampal oxidative stress, inflammation, and apoptosis in rats, and examined if the underlying mechanisms involve modulating Resolvin D1 (RvD1) levels and activation of p66Shc. Also, we tested if co-administration of RvD1 could prevent these neural adverse effects induced by CO-HFD. Adult male Wistar rats were divided into 4 groups (n = 18/each) as control fed standard diet (STD) (3.82 kcal/g), STD + RvD1 (0.2 µg/Kg, i.p/twice/week), CO-HFD (5.4 kcal/g), and CO-HFD + RvD1. All treatments were conducted for 8 weeks. With normal fasting glucose levels, CO-HFD induced hyperlipidemia, hyperinsulinemia, increased HOMA-IRI and reduced the rats' memory retention. In parallel, CO-HFD increased levels of reactive oxygen species (ROS), malondialdehyde (MDA), cytoplasmic cytochrome-c, and cleaved caspase-3 and significantly decreased levels of glutathione (GSH), Bcl-2, and manganese superoxide dismutase (MnSOD) in rats' hippocampi. Besides, CO-HFD significantly reduced hippocampal levels of docosahexaenoic acid (DHA) and RvD1, as well as total protein levels of Nrf2 and significantly increased nuclear protein levels of p-NF-κB. Concomitantly, CO-HFD increased hippocampal protein levels of p-JNK, p53, p66Shc, p-p66Shc, and NADPH oxidase. However, without altering plasma and serum levels of glucose, insulin, and lipids, co-administration of RvD1 to CO-HFD completely reversed all these events. It also resulted in similar effects in the STD fed-rats. In conclusion, CO-HFD impairs memory function and induces hippocampal damage by reducing levels of RvD1 and activation of JNK/p53/p66Shc/NADPH oxidase, effects that are prevented by co-administration of RvD1.

Towards a Valorization of Corn Bioethanol Side Streams: Chemical Characterization of Post Fermentation Corn Oil and Thin Stillage.

First-generation biofuel biorefineries may be a starting point for the development of new value chains, as their by-products and side streams retain nutrients and valuable molecules that may be recovered and valorized for high-value applications. This study provides a chemical characterization of post-fermentation corn oil and thin stillage, side streams of dry-grind corn bioethanol production, in view of their valorization. An overall long-term study was conducted on the two co-products collected over 1 year from a bioethanol plant. Water content, acid value, sedimentation, mineral composition, and fatty acid profiles were analyzed on post-fermentation corn oil. Results highlighted that its acid value was high (19.72-24.29 mg KOH/g), indicating high levels of free fatty acids, but stable over the year due to standardized operating conditions. The fatty acid profile was that typical of corn oil, with a prevalence of linoleic (54-59% of total fatty acids) over oleic (23-27%) and palmitic (12-17%) acids. Macronutrients, fatty acid, and mineral profiles were investigated in thin stillage. Results revealed the acidic pH (4.05-4.68) and high dilution (90-93% water) of this side stream. The dry mass was composed of fats (19-30%), proteins (8.8-12.8%), ash (8.7-9.5%), and fiber (7.3-9.8%). The concomitant presence of a variegate complex of molecules of nutritional interest in corn bioethanol co-products, with several potential high-value market applications, make the perspective of their recovery a promising strategy to create new cross-sector interconnections according to circular economy principles.

Experimental Model of Cirrhosis of the Liver.

A new model of cirrhosis of the liver was created in experiment on 30 rats. Over 3 weeks, experimental animals in addition to the standard diet daily intragastrically received corn oil in combination with intragastric administration of acetaminophen in a dose of 500 mg/day. High-fat load in combination with acetaminophen over 3 weeks led to the development of focal biliary cirrhosis.

Chronic consumption of a high-fat diet rich in corn oil activates intrinsic cell death pathway and induces several ultrastructural changes in the atria of healthy and type 1 diabetic rat.

This study investigates the effect of chronic consumption of a high-fat diet rich in corn oil (CO-HFD) on atrial cells ultrastructure, antioxidant levels and markers of intrinsic cell death of both control and type 1 diabetes mellitus (T1DM)-induced rats. Adult male rats (10 rats/group) were divided into four groups: control fed standard diet (STD) (3.82 kcal/g, 9.4% fat), CO-HFD (5.4 kcal/g, 40% fat), T1DM fed STD, and T1DM + CO-HFD. CO-HFD and T1DM alone or in combination impaired systolic and diastolic functions of rats and significantly reduced levels of GSH and the activity of SOD, enhanced lipid peroxidation, increased protein levels of P53, Bax, cleaved caspase-3, and ANF and decreased levels of Bcl-2 in their atria. Concomitantly, atrial cells exhibited fragmentation of the myofibrils, disorganized mitochondria, decreased number of atrionatriuretic factor (ANF) granules, and loss of gap junctions accompanied by changes in capillary walls. Among all treatments, the severity of all these findings was more severe in T1DM and most profound in the atria of T1DM + CO-HFD. In conclusion, chronic consumption of CO-HFD by T1DM-induced rats elicits significant biochemical and ultrastructural damage to rat atrial cells accompanied by elevated oxidative stress and mitochondria-mediated cell death.

Recovery of acid corn oil from the bioalcohol industry by molecular distillation.

BACKGROUND: The objective of this work was to reduce the acidity of acid corn oil for its subsequent use as edible oil. Also, its tocopherols composition was determined. This oil is obtained as a by-product of corn alcohol production on an industrial scale and is currently used as a raw material in the biodiesel industry. RESULTS: The tocopherols and fatty acids composition of acid corn oil was determined by gas chromatography, and molecular distillation experiments were carried out at different temperatures between 110 °C and 190 °C with a volumetric flow rate of 0.5 to 2 mL min-1 and a pressure of 5 × 10-5  atm. It was possible to reduce its acidity from 9.44% (as oleic acid) to values less than 0.3% in the residue, with distillation temperatures higher than 180 °C; also, in the distillate, the tocopherols were recovered with concentrations up to 13 360 ppm. CONCLUSION: It was possible to decrease the acidity and purify tocopherols from acid corn oil by molecular distillation, obtaining a residue with an acidity acceptable for human consumption and a distillate with a high tocopherols content. Therefore, using molecular distillation, added value was given to a by-product of the bioalcohol industry. © 2019 Society of Chemical Industry.

Stabilizing corn oil using the lemon balm (Melissa officinalis) antioxidants extracted by subcritical water.

This research was set up to identify the impact of the antioxidant compounds present in lemon balm extract (LBE) as obtained by the subcritical water (SBCW) method on the oxidative stability of corn oil. An extraction yield of 28.52% was obtained for the SBCW and rosmarinic acid was identified to be the predominant phenolic compound present in the LBE. The total phenolic content of the LBE was found to be 212.74 mg gallic acid/g extract. Subsequently, 200, 400, 800, 1600 and 3200 ppm of the LBE were added to corn oil and its peroxide value (PV), acid value (AV), conjugated diene (CD), carbonyl value (CV), oxidative stability index (OSI), total polar compound and total phenolic compounds were compared to control and the sample containing 200 ppm of the BHA throughout the 16-day Schaal oven test at 70 °C. Our findings indicated that the corn oil containing greater LBE concentration had lower PV, AV, CD, and CV but greater OSI than the control sample. Evaluation of total polar compounds confirmed lower extent of the compounds with high polarity in the greater levels of the LBE. Finally, the LBE was able to slow down the rancidity of corn oil and the samples with higher LBE exhibited gentle oxidation rate.

Role of lipolysis in postoral and oral fat preferences in mice.

Fatty acid receptors in the mouth and gut are implicated in the appetite for fat-rich foods. The role of lipolysis in oral- and postoral-based fat preferences of C57BL/6J mice was investigated by inhibiting lipase enzymes with orlistat. Experiment 1 showed that postoral lipolysis is required: mice learned to prefer (by 70%) a flavored solution paired with intragastric infusions of 5% soybean oil but not a flavor paired with soybean oil + orlistat (4 mg/g fat) infusions. Experiments 2-4 tested the oral attraction to oil in mice given brief choice tests that minimize postoral effects. In experiment 2, the same low orlistat dose did not reduce the strong (83-94%) preference for 2.5 or 5% soybean oil relative to fat-free vehicle in 3-min tests. Mice in experiment 3 given choice tests between two fat emulsions (2% triolein, corn oil, or soybean oil) with or without orlistat at a high dose (250 mg/g fat) preferred triolein (72%) and soybean oil (67%) without orlistat to the oil with orlistat but were indifferent to corn oil with and without orlistat. In experiment 4, mice preferred 2% triolein (62%) or soybean oil (89%) to vehicle when both choices contained orlistat (250 mg/g fat). Fatty acid receptors are thus essential for postoral but not oral-based preferences. Both triglyceride and fatty acid taste receptors may mediate oral fat preferences.

Potential Interference of Oil Vehicles on Genital Tubercle Development during the Fetal Period in ICR Mice.

Corn oil, sesame oil, and 10% ethanol in corn oil are commonly used as dosing vehicles in toxicology studies. Since these vegetable oils contain bioactive compounds, it is important for toxicology studies to characterize the toxicities of the dosing vehicles themselves. It has been recently proposed that the width of the genital tubercle (GT), the dorsal-ventral length (D-V length) of the GT, and urethral tube closure in mouse fetuses can be used as novel markers for monitoring sexual development in mice. However, how these parameters are influenced by the dosing vehicles themselves remains unclear. Therefore, we evaluated the effects of corn oil, sesame oil, and 10% ethanol in corn oil on GT width, D-V length, and GT morphology in ICR mice. Our results showed that all three vehicles influenced GT width and D-V length, but not GT morphology, suggesting that the effects of dosing vehicles themselves might need to be considered when GT width or D-V length is used as a parameter to evaluate the effects of chemicals on GT development.

Low-frequency ESR studies on permeable and impermeable deuterated nitroxyl radicals in corn oil solution.

Low-frequency electron spin resonance studies were performed for 2 mM concentration of deuterated permeable and impermeable nitroxyl spin probes, 3-methoxycarbonyl-2,2,5,5-tetramethyl-pyrrolidine-1-oxyl and 3-carboxy-2,2,5,5,-tetramethyl-1-pyrrolidinyloxy in pure water and various concentrations of corn oil solution. The electron spin resonance parameters such as the line width, hyperfine coupling constant, g factor, rotational correlation time, permeability, and partition parameter were estimated. The broadening of line width was observed for nitroxyl radicals in corn oil mixture. The rotational correlation time increases with increasing concentration of corn oil, which indicates the less mobile nature of spin probe in corn oil mixture. The membrane permeability and partition parameter values were estimated as a function of corn oil concentration, which reveals that the nitroxyl radicals permeate equally into the aqueous phase and oil phase at the corn oil concentration of 50%. The electron spin resonance spectra demonstrate the permeable and impermeable nature of nitroxyl spin probes. From these results, the corn oil concentration was optimized as 50% for phantom studies. In this work, the corn oil and pure water mixture phantom models with various viscosities correspond to plasma membrane, and whole blood membrane with different hematocrit levels was studied for monitoring the biological characteristics and their interactions with permeable nitroxyl spin probe. These results will be useful for the development of electron spin resonance and Overhauser-enhanced magnetic resonance imaging modalities in biomedical applications.

Kinetic modeling, recovery, and molecular characterization of poly-beta-hydroxybutyrate polymer in Acinetobacter baumannii isolate P39.

To control the poly-ß-hydroxybutyrate (PHB) biopolymer production by Acinetobacter baumannii isolate P39 kinetic modeling of the fermentation process, polymer downstream processing, enzymological analysis, and molecular characterization of PHA synthase, key biosynthetic enzyme, should be addressed. A. baumannii isolate P39 produced 0.15 g/L PHB after 24 h of incubation with a polymer content of 28% per dry weight. Logistic and Leudeking-Piret models were used for describing cell growth and PHB production, respectively. They showed good agreement with the experimental data describing both cell growth and PHB production (average regression coefficient r2:0.999). The growth-associated production of PHB biopolymer as an electron acceptor was confirmed using Leudeking-Piret model and victim substrate experiment. The best method of recovery of PHB biopolymer was chemical digestion using sodium hypochlorite, since it produced the largest amount of polymer and highest molecular weight (16,000 g/mole) in comparison to other recovery methods. DTNB assay showed high activity of PHA synthase enzyme, 600 U activity, and 153.8 U/mg specific activity. Molecular analysis of PHA synthase enzyme confirmed class III identity. Taken together, micelle model was proposed for polyhydroxybutyrate formation in A. baumannii isolate P39.

A comparison of total inward leakage measured using sodium chloride (NaCl) and corn oil aerosol methods for air-purifying respirators.

The International Organization for Standardization (ISO) standard 16900-1:2014 specifies the use of sodium chloride (NaCl) and corn oil aerosols, and sulfur hexafluoride gas for measuring total inward leakage (TIL). However, a comparison of TIL between different agents is lacking. The objective of this study was to measure and compare TIL for respirators using corn oil and NaCl aerosols. TIL was measured with 10 subjects donning two models of filtering facepiece respirators (FFRs) including FFP1, N95, P100, and elastomeric half-mask respirators (ERs) in NaCl and corn oil aerosol test chambers, using continuous sampling methods. After fit testing with a PortaCount (TSI, Inc., St. Paul, MN) using the Occupational Safety and Health Administration (OSHA) protocol, five subjects were tested in the NaCl chamber first and then in the corn oil chamber, while other subjects tested in the reverse order. TIL was measured as a ratio of mass-based aerosol concentrations in-mask to the test chamber, while the subjects performed ISO 16900-1-defined exercises. The concentration of NaCl aerosol was measured using two flame photometers, and corn oil aerosol was measured with one light scattering photometer. The same instruments were used to measure filter penetration in both chambers using a Plexiglas setup. The size distribution of aerosols was determined using a scanning mobility particle sizer and charge was measured with an electrometer. Filter efficiency was measured using an 8130 Automated Filter Tester (TSI). Results showed the geometric mean TIL for corn oil aerosol for one model each of all respirator categories, except P100, were significantly (p < 0.05) greater than for NaCl aerosol. Filter penetration in the two test chambers showed a trend similar to TIL. The count median diameter was ∼82 nm for NaCl and ∼200 nm for corn oil aerosols. The net positive charge for NaCl aerosol was relatively larger. Both fit factor and filter efficiency influence TIL measurement. Overall, TIL determination with aerosols of different size distributions and charges using different methodologies may produce dissimilar results.

Size segregated PM and its chemical composition emitted from heated corn oil.

Characterization of the airborne particulate matter (PM) emitted from cooking components including cooking oil, and additives like salt has not been carefully investigated. This study provides new data on the concentration, composition, and emission rates/fluxes of PM (less than 3.3µm) generated during heating corn oil and corn oil with added table salt. The concept of emission flux was employed to estimate the emission rates in this study. A statistically significant reduction of 47.6% (P<0.05) in the total PM emission rate and emission flux were observed when salt was added to the heated corn oil (5.15×101mgmin-1) compared to the pure oil (9.83×101mgmin-1). The OC emission rate decreased 61.3% (P<0.05) when salt was added to the corn oil (2.35×101mgmin-1) compared to the pure corn oil (5.83×101mgmin-1). With the salt, the total EC emission rate was 6.99×10-1mgmin-1, a 62.7% reduction in EC emission compared to pure corn oil (1.88mgmin-1). These results suggest that table salt can be added to the corn oil prior to frying to reduce exposure to cooking generated PM.