Quantitative structure-activity study of herbicidal N-aryl-3,4,5,6-tetrahydrophthalimides and related cyclic imides

The quantitative relationship between structure and inhibitory activity against the root growth of sawa millet of 30 N-aryl-3,4,5,6-tetrahydrophthalimides and 88 related N-aryl cyclic imide compounds (3-aryl-1,5-tetramethylenehydantoins, 4-aryl-1,2-tetramethylenetriazolidine-3,5-diones, and their thiocarbonyl analogs) was analyzed by means of physicochemical parameters of the aryl substituents and regression analysis. The results showed that, in each series of these classes of compounds, the position-specific steric effects of aromatic substituents, as represented by Verloop's STERIMOL values, are highly important in determining the inhibitory potency of the compound.     

西红柿黄顶病的初步研究

黄頂病在广州地区发生已有30—40年,过去只是零星发生,为害不大。但自1959年开始則发生普遍,1959年发病率为5—7％,1960年为9—17％,1961年为30—50％,1962年减少至2—3％,1963年又較严重发生,大面积的番茄也几乎全部感染,而且发病早,損失很大。本病在各种品种上的病状特点是:感病后植株顶叶叶色褪綠乃至黄化,叶片变小,叶面皺縮,中部稍凸起,边緣多向下或向上卷曲;严重时,整个叶片呈“棒状”,病株矮化,不定枝丛生。但在薯叶型的品种如“Karlik”上的病状特点則是:顶部     

Antioxidant properties and composition of aqueous extracts from Mentha species, hybrids, varieties, and cultivars

Water-soluble extracts from the Mentha species M. aquatica L. and M. haplocalyx Briq., the hybrids M. x dalmatica L. and M. x verticillata L., the varieties M. arvensis var. japanensis [M. arvensis L. var. piperascens Holmes ex Christ] and M. spicata L. var. crispa Benth, and M. x piperita L. "Frantsila", M. "Morocco", and M. "Native Wilmet" cultivars were screened for potential antioxidative properties. These properties included iron(III) reduction, iron(II) chelation, 1,1-diphenyl-2-picrylhydrazyl radical scavenging, and the ability to inhibit iron(III)-ascorbate-catalyzed hydroxyl radical-mediated brain phospholipid peroxidation. Total phenol content and qualitative and quantitative compositional analyses of each extract were also made. The extracts demonstrated varying degrees of efficacy in each assay, with the M. x piperita "Frantsila" extract being better than the other extracts, except for ferrous iron chelation. With the exception of iron chelation, it appeared that the level of activity identified was strongly associated with the phenolic content.     

Isolation of lignin from spruce by acidolysis in dioxane

Summary Acidolysis of spruce wood (Picea abies) corresponded to a pseudo-first order reaction mechanism. While anhydrous methanolis a better medium for wood acidolysis than anhydrous dioxane, after addition of 10% water dioxane became about twice as effective as methanol. The results are discussed in terms of acidity functions (H), solubility parameters and condensation effects. Infrared spectra of dioxane lignins showed a similar re-arrangement of side chain carboxyl groups from to position, as was observed previously during acidolysis in methanol.     

Characterization of Barley Leaf Tolerance to Drought Stress by Chlorophyll Fluorescence and Electron Paramagnetic Resonance Studies

Two kinds of barley genotypes with various water‐stress tolerances, tolerant Cam/B1 and sensitive Maresi, were subjected to 10‐day soil‐drought stress in seedling and flag leaf developmental phases. After this time, both genotypes regardless of the growth stage showed a decrease in quantum yield of PSII photochemistry (Φ_PSII) upon stress treatment; however, this effect was stronger in the sensitive plants than in the tolerant ones. The drought stress in the flag leaf stage was associated with an increase in superoxide dismutase (SOD) level in both genotypes, whereas in seedlings, this effect was observed only for Maresi. The activity of other enzymes (catalase and peroxidase) was changed only in small degree. An increase in proline levels and activities of Δ¹‐pyrroline‐5‐carboxylate synthetase (P5CS) and ornithine delta‐aminotransferase (OAT) were observed independently of genotype and the phase of plant development, whereas the activity pyruvate dehydrogenase (PDH) decreased in tolerant genotype. Moreover, changes in the concentration of monocarbohydrates (glucose and fructose) and dicarbohydrates (saccharose, raffinose and maltose) were found: in seedlings, the amount of all soluble sugars increased, while in flag leaves decreased. The drought treatment resulted in a drop in starch level in the tolerant genotype, but in the sensitive one, the content of this substance increased in both developmental stages. EPR studies allowed the determination of the amount and character of organic radicals present in leaves. In control conditions, the content of these radical species was higher in the sensitive genotype than in tolerant one and decreased upon water stress, with the exception of flag leaves of the sensitive plant. Simulation procedure revealed four types of signals in the EPR spectra. One of them was attributed to a chlorophyll a cation and decreased upon drought. The second, ascribed to semiquinone radicals, reflected the redox balance disturbed by water deficit. The two remaining signals were connected with carbon‐centred radicals situated in the carbohydrate matrix. Their number was correlated with starch concentration.     

Assessing the financial performance of water user associations: a case study at Great Menderes basin,Turkey

Management, operation and maintenance services of about 1.7 million ha irrigation areas, constructed the scheme by State Hydraulic Works (DSI) were turned over to Water User Association (WUA) in Turkey. The number of the WUAs is 330 in Turkey for 2005. There is therefore an urgent need to study methods of measurement and evaluation of financial performance of WUA in order to improve the financial performance and raise the management level of WUA. This paper proposes 12 financial indicators in order to measure and evaluate the financial performance of WUAs. Based on the results in four irrigation schemes and WUAs in Great Menderes basin, Turkey, the methods of measurement and calculation of financial performance indicators selected, and difference factor value related to each indicator are presented. Several financial performance indicators and difference factor values varied widely 1999 to 2004. Therefore, these financial performance indicators should be carefully evaluated and monitored for financial sustainability of WUAs.     

A new two-stage sampling design for estimating the maximum average time to flower

A horticulturist was considering the number of days (X) each variety took from planting seeds to reach the stage when the first bud appeared for three local marigold varieties. The data X could be recorded with accuracy of one-half day. The primary interest was to estimate the maximum waiting time between “seeding” and “first budding” among three varieties under consideration. It was thought that a 99% confidence interval with width one day would suffice. The horticulturist felt comfortable to assume a normal distribution for the response variable. He provided positive lower bounds for the variances which forced pilot sample sizes to become unequal. We are not aware of any existing methodology with unequal pilot sample sizes that would readily apply here. Accordingly, a new two-stage sampling design was developed and implemented. The gathered data validated all assumptions made during the course of this investigation. Important exact as well as large-sample properties of the proposed methodology are highlighted (Theorem 1). This methodology is proven to be theoretically superior (Theorem 2) to the existing methodology for large sample sizes provided that the pilot sizes could be “chosen” equal. For the experimental data on hand, the superiority of the new methodology has also been indicated (Section 4.3). The solution to the primary estimation problem ultimately led to a natural and yet nontraditional selection problem involving identification of the “worst” marigold variety. For this selection problem, a practical approach is developed (Section 4.4) for evaluating the associated probability of correctly selecting the worst marigold variety.     

Removal of 17α-Ethinylestradiol by Biogenic Manganese Oxides Produced by the Pseudomonas putida strain MnB1

Synthetic and persistent endocrine disrupting chemicals (EDCs) such as 17α-ethinylestradiol (EE2) have been frequently detected in the effluent of wastewater treatment plants and induce hazards to humans and wildlife. In this study, biogenic Mn oxides were tested for the removal of EE2, and factors affecting the reaction were also investigated. The biogenic Mn oxides produced by Pseudomonas putida strain MnB1 were nano-sized and poorly crystallized particles. A concentration of 7.9 mg l⁻¹ biogenic Mn oxides showed 87% EE2 (1 mg l⁻¹) removal efficiency in 2 h, which confirms the excellent potential of biogenic Mn oxides for removal of estrogens. EE2 removal was enhanced at high Mn oxide doses and at low pH. Co-existing heavy metals significantly inhibit EE2 removal, due to their competition for the reactive sites of biogenic Mn oxides. Humic acid (HA) also obstructed EE2 removal, but the adverse effect was alleviated as HA concentration increased, possibly due to the formation of soluble complexes with the released Mn²⁺, of which adsorption onto Mn oxides reduces surface reactive sites.     

Effect of maturation on the composition and biological activity of the essential oil of a commercially important Satureja species from Turkey: Satureja cuneifolia Ten. (Lamiaceae)

The essential oil obtained by hydrodistillation from aerial parts of Satureja cuneifolia Ten., collected in three different maturation stages such as preflowering, flowering, and postflowering, were analyzed simultaneously by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). Thymol (42.5-45.2%), p-cymene (19.4-24.3%), and carvacrol (8.5-13.2%) were identified as the main constituent in all stages. At the same time, the essential oils and main components were evaluated for their antimicrobial activity using a microdilution assay resulting in the inhibition of a number of common human pathogenic bacteria including methicillin-resistant Staphylococcus aureus (MRSA) and the yeasts Candida albicans and Candida tropicalis. The minimum inhibitory concentrations (MIC) varied between 62.5 and 250 microg/mL within a moderate antimicrobial activity range. Furthermore, the antioxidant capacity of the essential oils and major components thymol and carvacrol were examined in vitro. The essential oils obtained from S. cuneifolia in three different stages and its main components were interacted with 1,1-diphenyl-2-picrylhydrazyl (DPPH (*)) as a nitrogen-centered stable radical, resulting in IC 50 = 1.6-2.1 mg/mL. In addition, the effects on inhibition of lipid peroxidation of the essential oils were assayed using the beta-carotene bleaching method. All of the tested oils inhibited the linoleic acid peroxidation at almost the same level as butylated hydroxytoluene (BHT) (93.54-94.65%). BHT and ascorbic acid were used as positive controls in the antioxidant assays.