Effect of Fermentation Time and Leavening Agent on the Quality of Laboratory Produced and Market Samples of Masa (A Local Cereal Based Puff Batter)

Evaluation of production techniques, quality of market samples and effects of fermentation times (6 and 8hrs), leavening agents (yeasts and baking powder) and shelf life (fresh and 24h) on the quality of masa were carried out through interviews, processing operations, laboratory analyses and sensory studies. Statistical analyses were carried out using the SPSS Statistical Package. Variations in processing techniques among masa producers were method of preparing the rice, soaking time for the rice (4 – 6h), the time paste was allowed to stay before baker’s yeast was added (3 – 4h), frying time (4 -5 minutes) and ratios of cooked rice to soaked rice (1: 2 and 1: 4). Uniform practices among masa producers were washing, wet-milling, fermentation time (overnight), addition of yeast, salts and sugars and dilution of fairly thick batter with trona (baking powder) before frying. Functional properties of rice were foam capacity (23.7%), foam stability (88.5%), water absorption capacity (0.02%), gelation capacity (20%), gelatinization temperature (82oC) and gelation time (20 minutes) Significant differences were observed between the masa samples for ash, moisture, protein, lipid and total bacterial counts (p ≤ 0.05). Their ranges for both laboratory-processed and market samples, respectively were; moisture (10.2 – 11.7% and 12.0 – 13.7%); protein (7.1 – 7.6% and 7.6 – 8.2%); lipid (1.9 – 2.4% and 2.4 – 2.6%); ash (0.4 – 0.7% and 0.6 – 0.8%) and total bacterial counts (1.2 x 101 – 1.6 x101 cfu/g). For the first day of their production, significant differences (p ≤ 0.05) were observed for all the sensory factors for both laboratory-processed and market samples of masa. Based on sensory scores, all the laboratory-produced masa samples were organoleptically acceptable without much significant difference (p ≥ 0.05) except for masa fermented for 8h without leavening agent. The mean sensory scores of all fresh market samples of masa were less than 4.0 on a 7-point Hedonic scale. Significant differences were observed between the market and laboratory processed samples of masa after the first day of production for all the sensory factors (P ≤ 0.05) and 50% of market and laboratory produced masa samples were not sensorially acceptable. Unlike freshly produced (for both market and laboratory) masa samples, it was found out that after the first day (24h) of production, the trend was not the same. This is because unlike market samples of masa, laboratory prepared masa samples without leavening agents, were as unacceptable as masa samples with leavening agents.Key words: Masa, quality, Fermentation, Leavening, processin

Bioreduction of Cr (VI) by potent novel chromate resistant alkaliphilic Bacillus sp. strain KSUCr5 isolated from hypersaline Soda lakes

Isolation of Cr (VI) resistant alkaliphilic bacteria from sediment and water samples collected from Wadi Natrun hypersaline Soda lakes (located in northern Egypt), resulted in isolation of several alkaliphilic bacterial strains that can tolerate up to 2.94 g/l of Cr (VI) in alkaline medium. However, with increasing Cr (VI) concentration up to 29.4 g/l, only one strain, KSUCr5, was able to tolerate up to 22 g/l (75 mM) and with MIC value of 23.5 g/l (80 mM) in alkaline medium (pH 10.5) containing 10% NaCl. Based on the 16S rRNA gene analysis, strain KSUCr5 was identified as Bacillus sp. with 99% similarity and was referred to as Bacillus sp. KSUCr5. In addition, Bacillus sp. strain KSUCr5 showed high tolerance to several other heavy metals including Cd2+ (50 mM), Mo2+ (75 mM), Mn2+ (100 mM), Cu2+ (2 mM), Ni2+ (100 mM), Pb (75 mM), Co2+ (5 mM) and Zn2+ (2 mM). Strain KSUCr5 was shown to be of a high efficiency in detoxifying chromate, as it could rapidly reduce up to 40 mg/l of Cr(VI) to a non detectable level over 24 h. In addition, at initial Cr(VI) concentration of 60 to 80 and 100 mg/l, 100% of the chromate reduction was achieved within 48 and 72 h, respectively. Strain KSUCr5 could reduce Cr(VI) efficiently  over a wide range of initial Cr(VI) concentrations (10 to 300 mg/l) in alkaline medium under aerobic conditions without significant effect on the bacterial growth. It was able to reduce Cr(VI) in a wide range of NaCl (0 to 20%) with a maximum reduction yield at concentration of 0 to 1.5%, indicating the halo tolerance nature of the bacterium. It was found that addition of glucose and Na2CO3 to the culture medium caused a dramatic increase in Cr(VI)-reduction by Bacillus sp. strain KSUCr5. The maximum chromate removal was exhibited in alkaline medium (pH 10) containing 1.2% Na2CO3, 1.5% glucose and 1% NaCl and at incubation temperature of 35°C and culture shaking of 150 rpm. Under optimum Cr (VI) reduction conditions, Cr(VI) concentration of 80 mg/l was completely reduced within 24 h, with reduction rate of 3.3 mg h-1 which is one of the highest Cr(VI) reduction rate under high alkaline conditions, compared with other microorganisms that has been reported so far. Furthermore, the presence of other metals such as Ni2+, Mo2+, Cu2+ and Mn2+ at concentration of 100 mg/l together with Cr(VI) in the culture medium slightly increased Cr(VI)-reduction by the strain KSUCr5. Moreover, the isolate, Bacillus sp.  strain KSUCr5, exhibited an ability to repeatedly reduce hexavalent chromium without any amendment of nutrients, suggesting its potential application in continuous bioremediation of Cr(VI). The results reveal the possible isolation of potent heavy metals resistant bacteria from extreme environment such as hypersaline Soda lakes and their application in bioremediation of heavy metals.Key words: Chromate reduction, bioremediation, heavy metals, Bacillus sp., Soda lakes

Dual fluorescence from aqueous 1-naphthylamine solutions of high pH - Excited-state acidic dissociation of naphthylamine

Dual fluorescence at ca. 447 nm and 545 nm was observed from the aqueous 1-naphthylamine (NA) solutions at pH higher than 13.6. Similar dual fluorescence was also found with sodium 1-naphthylaminoacetate(NAA), but not with N, N-disubstituted 1-aminonaphthalenes such as sodium 1-naphthylaminodiacetate (NADA) and 1-dimethylaminonaphthalene (DMAN). No change in absorption spectra of NA and NAA was observed in this pH region. It was proposed that the dual fluorescence observed with NA and NAA was due to the excited state dissociation of the primary and secondary amines at high pH. From the dual fluorescence intensity ratio pH titration curve, the pK(a)(.)'s of NA and NAA were estimated to be between 14 and 15 which are much lower than the ground state pK(a). The novel approach is such a simple, convenient and frequent analysis technique that it can be widely used in detecting the substitutional derivatives of aminonaphthalene

A Clash of Old and New Scientific Concepts in Toxicity, with Important Implications for Public Health

Background A core assumption of current toxicologic procedures used to establish health standards for chemical exposures is that testing the safety of chemicals at high doses can be used to predict the effects of low-dose exposures, such as those common in the general population. This assumption is based on the precept that “the dose makes the poison”: higher doses will cause greater effects. Objectives We challenge the validity of assuming that high-dose testing can be used to predict low-dose effects for contaminants that behave like hormones. We review data from endocrinology and toxicology that falsify this assumption and summarize current mechanistic understanding of how low doses can lead to effects unpredictable from high-dose experiments. Discussion Falsification of this assumption raises profound issues for regulatory toxicology. Many exposure standards are based on this assumption. Rejecting the assumption will require that these standards be reevaluated and that procedures employed to set health standards be changed. The consequences of these changes may be significant for public health because of the range of health conditions now plausibly linked to exposure to endocrine-disrupting contaminants. Conclusions We recommend that procedures to establish acceptable exposure levels for endocrine-disrupting compounds incorporate the inability for high-dose tests to predict low-dose results. Setting acceptable levels of exposure must include testing for health consequences at prevalent levels of human exposure, not extrapolations from the effects observed in high-dose experiments. Scientists trained in endocrinology must be engaged systematically in standard setting for endocrine-disrupting compounds

Imaging Oxygen Defects and their Motion at a Manganite Surface

Manganites are technologically important materials, used widely as solid oxide fuel cell cathodes: they have also been shown to exhibit electroresistance. Oxygen bulk diffusion and surface exchange processes are critical for catalytic action, and numerous studies of manganites have linked electroresistance to electrochemical oxygen migration. Direct imaging of individual oxygen defects is needed to underpin understanding of these important processes. It is not currently possible to collect the required images in the bulk, but scanning tunnelling microscopy could provide such data for surfaces. Here we show the first atomic resolution images of oxygen defects at a manganite surface. Our experiments also reveal defect dynamics, including oxygen adatom migration, vacancy-adatom recombination and adatom bistability. Beyond providing an experimental basis for testing models describing the microscopics of oxygen migration at transition metal oxide interfaces, our work resolves the long-standing puzzle of why scanning tunnelling microscopy is more challenging for layered manganites than for cuprates.Comment: 7 figure

Decreased Serum Free Testosterone in Workers Exposed to High Levels of Di-n-butyl Phthalate (DBP) and Di-2-ethylhexyl Phthalate (DEHP): A Cross-Sectional Study in China

BACKGROUND: Observations of adverse developmental and reproductive effects in laboratory animals and wildlife have fueled increasing public concern regarding the potential for various chemicals to impair human fertility. OBJECTIVE: Our objective in this study was to assess the effect of occupational exposure to high levels of phthalate esters on the balance of gonadotropin and gonadal hormones including luteinizing hormone, follicle-stimulating hormone, free testosterone (fT), and estradiol. METHODS: We examined urine and blood samples of 74 male workers at a factory producing unfoamed polyvinyl chloride flooring exposed to di-n-butyl phthalate (DBP) and di-2-ethylhexyl phthalate (DEHP) and compared them with samples from 63 male workers from a construction company, group matched for age and smoking status. RESULTS: Compared to the unexposed workers, the exposed workers had substantially and significantly elevated concentrations of mono-n-butyl phthalate (MBP; 644.3 vs. 129.6 μg/g creatinine, p < 0.001) and mono-2-ethylhexyl phthalate (MEHP; 565.7 vs. 5.7 μg/g creatinine, p < 0.001). fT was significantly lower (8.4 vs. 9.7 μg/g creatinine, p = 0.019) in exposed workers than in unexposed workers. fT was negatively correlated to MBP (r = −0.25, p = 0.03) and MEHP (r = −0.19, p = 0.095) in the exposed worker group. Regression analyses revealed that fT decreases significantly with increasing total phthalate ester score (the sum of quartiles of MBP and MEHP; r = −0.26, p = 0.002). CONCLUSION: We observed a modest and significant reduction of serum fT in workers with higher levels of urinary MBP and MEHP compared with unexposed workers

Characterizations of ordered semigroups in terms of (∈, ∈ ∨q)-fuzzy interior ideals

In this paper, we give characterizations of ordered semigroups in terms of (∈, ∈ ∨q)-fuzzy interior ideals. We characterize different classes regular (resp. intra-regular, simple and semisimple) ordered semigroups in terms of (∈, ∈ ∨q)-fuzzy interior ideals (resp. (∈, ∈ ∨q)-fuzzy ideals). In this regard, we prove that in regular (resp. intra-regular and semisimple) ordered semigroups the concept of (∈, ∈ ∨q)-fuzzy ideals and (∈, ∈ ∨q)-fuzzy interior ideals coincide. We prove that an ordered semigroup S is simple if and only if it is (∈, ∈ ∨q)-fuzzy simple. We characterize intra-regular (resp. semisimple) ordered semigroups in terms of (∈, ∈ ∨q)-fuzzy ideals (resp. (∈, ∈ ∨q)-fuzzy interior ideals). Finally, we consider the concept of implication-based fuzzy interior ideals in an ordered semigroup, in particular, the implication operators in Lukasiewicz system of continuous-valued logic are discussed

Post-Lie Algebras, Factorization Theorems and Isospectral-Flows

In these notes we review and further explore the Lie enveloping algebra of a post-Lie algebra. From a Hopf algebra point of view, one of the central results, which will be recalled in detail, is the existence of a second Hopf algebra structure. By comparing group-like elements in suitable completions of these two Hopf algebras, we derive a particular map which we dub post-Lie Magnus expansion. These results are then considered in the case of Semenov-Tian-Shansky's double Lie algebra, where a post-Lie algebra is defined in terms of solutions of modified classical Yang-Baxter equation. In this context, we prove a factorization theorem for group-like elements. An explicit exponential solution of the corresponding Lie bracket flow is presented, which is based on the aforementioned post-Lie Magnus expansion.Comment: 49 pages, no-figures, review articl

Rapid generation of endogenously driven transcriptional reporters in cells through CRISPR/Cas9

CRISPR/Cas9 technologies have been employed for genome editing to achieve gene knockouts and knock-ins in somatic cells. Similarly, certain endogenous genes have been tagged with fluorescent proteins. Often, the detection of tagged proteins requires high expression and sophisticated tools such as confocal microscopy and flow cytometry. Therefore, a simple, sensitive and robust transcriptional reporter system driven by endogenous promoter for studies into transcriptional regulation is desirable. We report a CRISPR/Cas9-based methodology for rapidly integrating a firefly luciferase gene in somatic cells under the control of endogenous promoter, using the TGFβ-responsive gene PAI-1. Our strategy employed a polycistronic cassette containing a non-fused GFP protein to ensure the detection of transgene delivery and rapid isolation of positive clones. We demonstrate that firefly luciferase cDNA can be efficiently delivered downstream of the promoter of the TGFβ-responsive gene PAI-1. Using chemical and genetic regulators of TGFβ signalling, we show that it mimics the transcriptional regulation of endogenous PAI-1 expression. Our unique approach has the potential to expedite studies on transcription of any gene in the context of its native chromatin landscape in somatic cells, allowing for robust high-throughput chemical and genetic screens