Identification of lactic acid bacteria isolated from oat sourdoughs and investigation into their potential for the improvement of oat bread quality

The use of sourdough in wheat and rye breads has been extensively studied; however, little is known about its potential effect when baking oat bread. Consequently, the impact of sourdough on oat bread quality was investigated. Two different sourdoughs were prepared from wholegrain oat flour without the addition of starter cultures, by continuous propagation at 28 (SD 28) or 37 °C (SD 37) until the composition of the lactic acid bacteria remained stable. The dominant LAB were identified by sequence analysis of the 16S rDNA isolated from pure cultures. LAB from SD 28 belonged to the species Leuconostoc argentinum, Pedicoccus pentosaceus and Weissella cibaria, while Lactobacillus coryniformis dominated SD 37. The isolated LAB were further used as starter cultures for the production of oat sourdoughs. Fundamental rheology revealed softening of the sourdoughs compared to non-acidified and chemically acidified controls, which could not be attributed to proteolytic activity. Incorporation of oat sourdough into an oat bread recipe resulted in significantly increased loaf-specific volume as well as improved texture, independent of addition level or sourdough type. Overall, the results of this study show that sourdoughs containing lactic acid bacteria isolated from oats have the potential to enhance oat bread quality.     

Antifungal Activity of Lactic Acid Bacteria Isolated from Peanuts,Gari, and Orange Fruit Juice against Food Aflatoxigenic Molds

This study aims to evaluate the antifungal activity of lactic acid bacteria (LAB) from some Cameroonian food commodities against mycotoxigenic and spoilage molds. Following LAB isolation, the antifungal activity of the isolates was assessed. The organic acids were quantified using high-performance liquid chromatography and the ability of the LAB to reduce mold biomass and aflatoxin production was evaluated. The LAB were identified and the biopreservative potential of strain LO3 was evaluated on tomato paste. Nine percent of the strains isolated showed broad antifungal activity. The activity was due to the effect of organic acids comprising lactic, acetic, 4-hydroxy-3-phenyllactic and 3-phenyllactic acids. Lactobacillus plantarum LO3 exhibiting the highest and broadest antifungal activity was selected and showed the capacity to inhibit fungal growth and aflatoxin production in vitro. Moreover, this strain and its cell-free supernatant showed the ability to prevent aflatoxigenic mold growth in tomato paste without altering its physico-chemical and organoleptic properties.     

Gender differences relative to smoking behavior and emissions of toxins from mainstream cigarette smoke.

This study examined whether gender differences exist in the exposure to select mainstream cigarette smoke toxins as a result of differences in smoking behavior or type of cigarettes smoked among 129 female and 128 male smokers. Smoking topography data indicated that, compared with men, women took smaller puffs (37.6 ml/puff vs. 45.8 ml/puff; p = .0001) of shorter duration (1.33 s/puff vs. 1.48 s/puff; p = .002) but drew more puffs per cigarette (13.5 vs. 12.0; p = .001) and left longer butts (36.3 mm or 40.2% of cigarette length vs. 34.3 mm or 39.2% of cigarette length; p = .01). These trends were similar in both African Americans and European Americans. The emissions of select toxins per cigarette, as determined by mimicking human smoking behaviors were greater among the male smokers than the female smokers and correlated significantly with delivered smoke volume per cigarette. The geometric means of emissions of nicotine from cigarettes were 1.92 mg/cigarette (95% CI = 1.80-2.05) for women versus 2.20 (95% CI = 2.04-2.37) for men (p = .005). Cigarettes smoked by women yielded 139.5 ng/cigarette of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK; 95% CI = 128.8-151.0), compared with 170.3 ng/cigarette (95% CI = 156.3-185.6) for men (p = .0007); benzo(a)pyrene (BaP) emissions were 18.0 ng/cigarette (95% CI = 17.0-19.0) for women and 20.5 ng/cigarette (95% CI = 18.8-22.3) for men (p = .01). The gender differences with regard to cigarette smoke yields of toxins were more profound in European Americans than in African Americans. On average, African American men's smoking habits produced the highest emissions of select toxins from cigarettes, and European American female smokers had the lowest exposure to carcinogens and toxins. Several studies have suggested that women may be more susceptible than men to the ill effects of carcinogens in tobacco and tobacco smoke, whereas other studies have not found differences in lung cancer risk between men and women. The present study suggests that gender differences in exposure to tobacco smoke cannot account for a higher rate of lung cancer in female smokers compared with male smokers.     

Chemical cues identify gender and individuality in Giant pandas (Ailuropoda melanoleuca)

The Giant panda communicates with conspecifics by depositing a mixture of volatile compounds (called scent marks) on trees and rocks. Using mass spectrometry, we identified 951 chemical components from scent glands, urine, vaginal secretions, and scent marks made by pandas. The scent marks of the two genders contained a similar array of chemicals but varied in concentration; specifically, males possessed a significantly greater amount of short chain fatty acids (F(1, 29) = 18.4, P = 0.002). Using stepwise discriminate analysis on the relative proportions of a subset of these chemicals, it was possible to classify gender (94% for males and females) and individuality (81% for males and 91% for females) from scent marks. The power to identify individual males was reduced due to the relatedness of two subjects. By cracking the identity code of Giant panda communication, we show insights into how these animals can match individuals with unique chemical profiles. Since radiocollaring is currently banned in China, the techniques described in this paper give field biologists a new means to identify and track pandas in the wild.     

IR spectroscopy: Suitable method for determination of curing degree and crosslinking type in melamine–formaldehyde resins

Melamine–formaldehyde (MF) resins are widely used as adhesives and finishing materials in the wood industry. During resin cure, either methylene ether or methylene bridges are formed, leading to the formation of a three-dimensional resin network. Not only the curing degree, but also the chemical species present in the cured resin determine the quality of the final product. Analytical methods allowing a detailed investigation of network formation are of great benefit to manufacturers. In the present work, resin cure of an MF precondensate is studied at different temperatures (100–200 °C) without considering the initial pH as a factor. Isoconversional kinetic analysis based on exothermal curing enthalpies enables calculation of the crosslinking degree at a given time/temperature regime. A semiquantitative determination of the chemical groups present is performed based on solid-state nuclear magnetic resonance data. Fourier transform infrared spectroscopy has shown to be a fast and reliable analytical tool with high sensitivity toward functional groups and with great potential for at-line process control. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47691.     

Isomorphic Implication

We study the isomorphic implication problem for Boolean constraints. We show that this is a natural analog of the subgraph isomorphism problem. We prove that, depending on the set of constraints, this problem is in P, or is NP-complete, or is NP-hard, coNP-hard, and in P_‖^NP. We show how to extend the NP-hardness and coNP-hardness to P_‖^NP-hardness for some cases, and conjecture that this can be done in all cases. Supported in part by grants NSF-CCR-0311021 and DFG VO 630/5-1 and VO 630/5-2. An extended abstract of this paper appears in Proceedings of the 30th International Symposium on Mathematical Foundations of Computer Science (MFCS 2005), pp. 119–130, Springer-Verlag Lecture Notes in Computer Science #3618, August 2005. Work of M. Bauland done in part while visiting CASCI’s Laboratory for Complexity at Rochester Institute of Technology. Work of E. Hemaspaandra done in part while on sabbatical at the University of Rochester.     

Generalized modal satisfiability

It is well known that modal satisfiability is PSPACE-complete (Ladner (1977) [21]). However, the complexity may decrease if we restrict the set of propositional operators used. Note that there exist an infinite number of propositional operators, since a propositional operator is simply a Boolean function. We completely classify the complexity of modal satisfiability for every finite set of propositional operators, i.e., in contrast to previous work, we classify an infinite number of problems. We show that, depending on the set of propositional operators, modal satisfiability is PSPACE-complete, coNP-complete, or in P. We obtain this trichotomy not only for modal formulas, but also for their more succinct representation using modal circuits. We consider both the uni-modal and the multi-modal cases, and study the dual problem of validity as well.