Identification of Photoproducts of Hexahydroquinoline Derivatives by GC-EI-MS and HPLC-ESI-MS

Photoproducts of hexahydroquinoline derivatives have been analyzed with gas chromatography electro ionization-mass spectrometry (GC-EI-MS) and high performance chromatography electrospray ionization-mass spectrometry (HPLC-ESI-MS). The study was performed on four HHQ derivatives: 2,6,6-trimethyl-3-carbomethoxy-5-oxo-4-(R-phenyl)-1,4,5,6,7,8-hexahydroquinoline; R=2′-Me, 3′-Me, 2′-MeO, and 3′-MeO. The photochemical degradation of each of the HHQ derivatives led to the appearance of one product. The photoproducts were identified as the corresponding tetrahydroquinoline analogues, which were formed by dehydrogenation of dihydropyridine moiety. In GC-mass spectra, the most frequent way of fragmentation was elimination of CH₃* or CH₃O* radical of the ester group. In the photoproducts substituted at 2′-position of the phenyl ring, elimination of isobutene (C₄H₈) was observed. In the photoproducts with 3′-position substituents, elimination of COOCH₃* radical was noted.     

The effect of high pressure treatment and cryotexturization on odorant mixture binding by corn,sorghum and amaranth starch

The binding extent of odorant mixtures from aqueous suspensions by native, high pressure-treated starches and starch cryotexturizates was studied using capillary gas chromatography. The materials were corn, sorghum and amaranth starches. The native and high pressure-treated (650 MPa/9 min) starches were mixed with odorants and incubated (24 h) at room temperature. To obtain the cryotexturizate-odorant product, starch gels were frozen with odorants (−24 °C), stored (48 h) and thawed. Terpene hydrocarbons were strongly bound from the mixture by all the starches analyzed. The nonpolar molecules of terpene hydrocarbons modified the nature of hydrophobic binding sites in starch which in turn affected binding affinity of alcohols, ketones and phenols to the preparations. The competition effect between odorants for the binding sites was found. The varied ability of starch preparations to bind odorants was also related to the granule morphology and alteration in their structure upon treatment used.     

5-HT Receptors and the Development of New Antidepressants

Serotonin modulates several physiological and cognitive pathways throughout the human body that affect emotions, memory, sleep, and thermal regulation. The complex nature of the serotonergic system and interactions with other neurochemical systems indicate that the development of depression may be mediated by various pathomechanisms, the common denominator of which is undoubtedly the disturbed transmission in central 5-HT synapses. Therefore, the deliberate pharmacological modulation of serotonergic transmission in the brain seems to be one of the most appropriate strategies for the search for new antidepressants. As discussed in this review, the serotonergic system offers great potential for the development of new antidepressant therapies based on the combination of SERT inhibition with different pharmacological activity towards the 5-HT system. The aim of this article is to summarize the search for new antidepressants in recent years, focusing primarily on the possibility of benefiting from interactions with various 5-HT receptors in the pharmacotherapy of depression.     

Importance of weather monitoring for agricultural decision‐making – an exploratory behavioral study for Oklahoma Mesonet

BACKGROUND

The Oklahoma Mesonet (the statewide environmental and weather monitoring network) has monitored changes in weather patterns since 1994 to provide accurate and timely mesoscale weather information to farmers and other groups. Studies are still scarce that would quantitatively assess farmers' perceptions about the value of the Oklahoma Mesonet contributions to agricultural operations, profitability of land management, and decision making. This paper aims to analyze those questions by means of an exploratory empirical study in Oklahoma for two groups of Mesonet users and non‐users.

RESULTS

Familiarity with and application of Mesonet information determines farmers' profitability assessments and decision making. Farmers' perceptions are also influenced by the degree of previous exposure to weather‐related losses. The median estimate of the economic value of Mesonet information is $1000 per year. Mesonet users perceive higher profitability from the application of Mesonet data at 7.6/10, whereas Mesonet non‐users provided an average assessment of 2.6/10.

CONCLUSIONS

Consistent use of Mesonet information results in a higher assessment of the importance of Mesonet. This research provides some initial insights into farmers' perceptions about the value of Oklahoma Mesonet information, which could guide stakeholders in developing measures to better serve farmers with environmental monitoring data for improved farm decisions. © 2018 Society of Chemical Industry     

Detection of B<Subscript>6</Subscript> Vitamers in Grain Products: Experimental and Computational Studies

A reversed phase high-performance liquid chromatography method (HPLC) with coulometric electrochemical detection has been applied and validated for the simultaneous analysis of pyridoxamine (PM), pyridoxal (PL), and pyridoxine (PN) in cereal products. Isocratic separation was achieved using a C₁₈ column with a mobile phase consisting of methanol-phosphate buffer (10:90) and 0.018 M trimethylamine adjusted to pH 3.55 with 85% orthophosphoric acid. The limits of detection for PM, PL, and PN were 0.28, 0.36, and 0.43 ng mL^?1, respectively, with vitamins recoveries ranging from 90.4 to 98.1%. The applied method for the analysis of B₆ vitamins naturally present in grain products, offers a simple and fast sample preparation without derivatization. To understand vitamer separation further, methods of computational chemistry were employed. Specifically, density functional theory (DFT) was used to determine electrostatic potentials, as well as the charges of each vitamer. A number of correlations were established between these properties and elution order.     

The influence of chloroacetamide /AC/ and N-bromoacetamide /AB/ on the dielectric properties of TGS crystals

Dielectric hysteresis loops for TGS crystals admixtured with AC or AB were observed not to be symmetric in the case of aged crystals. By this asymmetry WP man that one of the branches of the hysteresis loop is symmetric and the other is distorted. The influence of AC or AB admixture on the domain structure and aping process of TGS crystals was studied as well.     

Effect of deuteration on the phase transition of pure and Cr3 -doped triglycine selenate TGSe

Results of dielectric studies are reported in triglycine selenate crystals DTGSe, pure and admixtured with chromium ion DTGSe+ Cr³⁺. From these results and observations double hysteresis loops above the Curie temperature, the DTGSe and DTGSe + Cr³⁺ crystals are found to undergo a phase transition of the I-st kind.