57 research outputs found

    Genetic and phenotypic variability of yield components in wheat (Triticum aestivum L.)

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    Variability, heritability and components of variance for number of grains per spike and grain weight per spike have been studied in 10 winter wheat varieties from different selection centers (Arsenal, KG-56, Gruza, Mironovskaya 808, Norin 10, Rana Niska, Spartanka, Sterna, Osjecanka, and Szegedi 765). The experiment was performed in randomized block design in three replications on the experimental field of Small Grains Research Centre, Kragujevac in three years. Average estimated values for number of grains per spike and grain weight per spike differed significantly among years and among varieties. The highest average value for number of grains per spike had Szegedi 765 variety ( x = 75.1) and the lowest value was found in Spartanka ( x = 56.0). During investigated period the highest average value for grain weight per spike was determined in Gruza ( Norin 10 ( x = 2.9 g), and the lowest value in x = 2.0 g). The average variation coefficient for number of grains per spike was 17.4%, and for grain weight per spike was 21.4%. The lowest variability for number of grains per spike and grain weight per spike was established in Sterna variety (V = 13.0%; 16.2%, respectively) and the highest in Norin 10 variety (V = 21.6%; 25.1%, respectively). Obtained heritability value in broad sense for number of grains per spike was about 60%, and for grain weight per spike about 40%. Statistical analysis of variance established highly significant differences in mean values for number of grains per spike and grain weight per spike. Phenotypic analysis of variance indicated that ecological factors had higher impact on the expression of number of grains per spike and grain weight per spike than genetic factors

    Removal of the selected pesticides from a water solution applying hollow fiber liquid-liquid membrane extraction

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    A supported liquid membrane extraction of different pesticides (acetamiprid, dimethoate, imidacloprid, linuron, and tebufenozide) from an aqueous solution containing 20 mg dm–3 of each pesticide by 5% TOPO (tri-n-octylphosphine oxide) in DHE (di-n-hexyl ether) has been investigated in a hollow fiber contactor having an aqueous feed/organic interfacial area of 15.4 cm2. In a single-pass operation, the maximum removal efficiency of 95% was achieved for the most nonpolar (log P = 4.38) pesticide tebufenozide at the feed flow rate of 0.5 cm3 min–1. The diffusion through the boundary layer of the feed stream was a rate-controlling step in the extraction of nonpolar pesticides (linuron and tebufenozide) with a mass-transfer coefficient in the feed stream being proportional to the feed flow rate raised to the power of 0.51–0.57. The maximum overall mass-transfer coefficient based on the feed phase of KF = 0.18 cm min–1 was obtained for tebufenozide at the feed flow rate of 1.8 cm3 min–1. The organic phase entrapped in the membrane pores offered a major resistance to the mass transfer of polar pesticides (log P < 1) and accounted for 85% of the overall mass-transfer resistance for imidacloprid at 1.8 cm3 min–1. The pesticides removed from the feed solution were almost completely accumulated in the organic phase but were recovered from the membrane pores to a large extent (50–90%) by rinsing the membrane with methanol after extraction

    Liquid phase membrane extraction of targeted pesticides from manufacturing wastewaters in a hollow fiber contactor with feed-stream recycles

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    A two-phase membrane extraction in a hollow fibre contactor with feed-stream recycle was applied to remove selected pesticides (tebufenozide, linuron, imidacloprid, acetamiprid and dimethoate) from their mixed aqueous solutions. The contactor consisted of 50 polypropylene hollow fibers impregnated with 5% tri-n-octylphosphine oxide in di-n-hexyl ether. For low polar pesticides with log P ˃ 2 (tebufenozide and linuron), the maximum removal efficiency increased linearly from 85 to 96% with increasing the feed flow rate. The maximum removal efficiencies of more polar pesticides were significantly higher under feed recirculation (86%) than in a continuous single pass operation (30%). It was found from the Wilson's plot that the mass transfer resistance of the liquid membrane can be neglected for low polar pesticides. The pesticide removals from commercial formulations were similar to those from pure pesticide solutions, indicating that built-in adjuvants did not affect the extraction process

    Fate and removal of pharmaceuticals and illicit drugs in conventional and membrane bioreactor wastewater treatment plants and by riverbank filtration

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    26 pages, 3 tables, 3 figures.Pharmaceutically active compounds (PhACs) and drugs of abuse (DAs) are two important groups of emerging environmental contaminants that have raised an increasing interest in the scientific community. A number of studies revealed their presence in the environment. This is mainly due to the fact that some compounds are not efficiently removed during wastewater treatment processes, being able to reach surface and groundwater and subsequently, drinking waters. This paper reviews the data regarding the levels of pharmaceuticals and illicit drugs detected in wastewaters and gives an overview of their removal by conventional treatment technologies (applying activated sludge) as well as advanced treatments such as membrane bioreactor. The paper also gives an overview of bank filtration practices at managed aquifer recharge sites and discusses the potential of this approach to mitigate the contamination by PhACs and DAs.This work has been supported by the EU project INNOVA-MED (INCO-CT-2006-517728) and by the Spanish Ministry of Science and Innovation Projects CTM2007-30524-E and CEMAGUA (CGL2007-64551).Peer reviewe

    The subchronic effects of 3,4-methylendioxymethamphetamine on oxidative stress in rat brain

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    The aim of the present study was to evaluate the subchronic effects of 3,4-methylenedioxymethamphetamine on several oxidative stress markers: index of lipid peroxidation (ILP), superoxide dismutase (SOD) activity, superoxide radical (O2.-) levels, and reduced glutathione (GSH) levels in the frontal cortex, striatum and hippocampus of the rat. The study included 64 male Wistar rats (200-250 g). The animals were treated per os with of 5, 10, or 20 mg/kg of 3,4-methylenedioxymethamphetamine (MDMA) every day for 15 days. The subchronic administration of MDMA resulted in an increase in ILP, SOD and O2.-, and a decrease in GSH, from which we conclude that oxidative stress was induced in rat brain

    Liquid-phase microextraction in a single hollow fibre: determination of mass transfer coefficient

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    In this study, the mass transfer coefficient of two local anesthetics in liquidphase microextraction (LPME), which is performed in a single hollow fibre, was investigated. Previously developed mathematical model has been applied for the determination of the overall mass transfer coefficient based on the acceptor phase, KA, in an unsteady-state LPME

    Voltammetric Detection of 5-Hydroxytryptamine Release in the Rat Brain

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    5-HT is an important molecule in the brain that is implicated in mood and emotional processes. In vivo, its dynamic release and uptake kinetics are poorly understood due to a lack of analytical techniques for its rapid measurement. Whereas fast-scan cyclic voltammetry with carbon fiber microelectrodes is used frequently to monitor sub-second dopamine release in freely-moving and anesthetized rats, the electrooxidation of 5-HT forms products that quickly polymerize and irreversibly coat the carbon electrode surface. Previously described modifications of the electrochemical waveform allow stable and sensitive 5-HT measurements in mammalian tissue slice preparations and in the brain of fruit fly larvae. For in vivo applications in mammals, however, the problem of electrode deterioration persists. We identify the root of this problem to be fouling by extracellular metabolites such as 5-HIAA, which is present in 200-1000 times the concentration of 5-HT and displays similar electrochemical properties, including filming of the electrode surface. To impede access of the 5-HIAA to the electrode surface, a thin layer of Nafion®, a cation exchange polymer, has been electrodeposited onto cylindrical carbon-fiber microelectrodes. The presence of the Nafion® film was confirmed with environmental scanning electron microscopy and was demonstrated by the diminution of the voltammetric signals for 5-HIAA as well as other common anionic species. The modified microelectrodes also display increased sensitivity to 5-HT, yielding a characteristic cyclic voltammogram that is easily distinguishable from other common electroactive brain species. The thickness of the Nafion® coating and a diffusion coefficient (D) in the film for 5-HT were evaluated by measuring permeation through Nafion®. In vivo, we used physiological, anatomical and pharmacological evidence to validate the signal as 5-HT. Using Nafion®-modified microelectrodes, we present the first endogenous recording of 5-HT in the mammalian brain

    HEADSPACE VOLATILES OF CHAEROPHYLLUM AUREUM L.

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    Differences in the headspace volatile profiles (HS) of fresh and air-dried fruits, stems and aerial parts of Chaerophyllum aureum L. (Apiaceae) were studied here for the first time using HS-GC-MS (head space – gas chromatography – mass spectrometry). This was done in order to probe to which level HS volatiles of different plant organs were susceptible to air drying. The most dominant headspace volatiles of all samples were monoterpene hydrocarbons. Sabinene was the major volatile of the fresh aerial parts, air-dried fruits, fresh and air-dried stems, representing 47.8%, 31.4%, 67.7% and 73.0% of the total volatiles, respectively. The most abundant headspace volatiles of the fresh fruits were terpinolene (45.3%), γ-terpinene (13.1%) and β-pinene (10.2%). The air-dried aerial parts were characterized by a high amount of limonene (69.0%). The results of HS-GC-MS were subjected to multivariate statistical analysis in order to get a better insight into the similarities/dissimilarities existing between the investigated samples. According to the results of multivariate analysis, the drying process significantly influenced HS volatiles. ISPARLJIVI SASTOJCI BILJNE VRSTE CHAEROPHYLLUM AUREUM L.U ovom radu su, po prvi put, ispitane razlike u headspace profilima (HS) svežih i na vazduhu sušenih plodova, stabljika i nadzemnih delova biljne vrste Chaerophyllum aureum L (Apiaceae) pomoću metode HS-GC-MS (headspace – gasna hromatografija – masena spektrometrija). Na osnovu ovih rezultata moglo bi se utvrditi do koliko intenzivnih promena u HS profilima različitih delova biljke može doći usled sušenja biljnog materijala. U svim uzorcima su dominantni headspace isparljivi sastojci bili monoterpeni. Utvrđeno je da je sabinen bio glavni isparljivi sastojak svežeg nadzemnog dela (47,8%), suvog ploda (31,4%), svežeg (67,7%) i suvog stabla (73,0%). Kao glavni isparljivi sastojci svežeg ploda nađeni su terpinolen (45,3%), γ-terpinen (13,1%) i β-pinen (10,2%), dok je suvi nadzemni deo bio okarakterisan značajno većom zastupljenošću limonena (69,0%). Rezultati HS-GC-MS analize su podvrgnuti multivarijantnoj statističkoj analizi kako bi se dobio bolji uvid u sličnosti/razlike među razmatranim uzorcima. Na osnovu rezultata multivarijantne analize sledi da sušenje u velikoj meri utiče na HS profil. HIGHLIGHTSHeadspace (HS) profiles (percentage compositions) of different parts of Chaerophyllum aureum L. were subjected to multivariate statistical analysis.In all samples, fresh and dry, the most dominant headspace volatiles were monoterpene hydrocarbons.Sabinene was the most abundant volatile of the fresh aerial parts, air-dried fruits, fresh and air-dried stems.The main headspace volatile compound of the fresh fruits was terpinolene while limonene was the major volatile of the air-dried aerial parts

    Analysis of pharmaceuticals in wastewater and removal using a membrane bioreactor

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    Much attention has recently been devoted to the life and behaviour of pharmaceuticals in the water cycle. In this study the behaviour of several pharmaceutical products in different therapeutic categories (analgesics and anti-inflammatory drugs, lipid regulators, antibiotics, etc.) was monitored during treatment of wastewater in a laboratory-scale membrane bioreactor (MBR). The results were compared with removal in a conventional activated-sludge (CAS) process in a wastewater-treatment facility. The performance of an MBR was monitored for approximately two months to investigate the long-term operational stability of the system and possible effects of solids retention time on the efficiency of removal of target compounds. Pharmaceuticals were, in general, removed to a greater extent by the MBR integrated system than during the CAS process. For most of the compounds investigated the performance of MBR treatment was better (removal rates >80%) and effluent concentrations of, e.g., diclofenac, ketoprofen, ranitidine, gemfibrozil, bezafibrate, pravastatin, and ofloxacin were steadier than for the conventional system. Occasionally removal efficiency was very similar, and high, for both treatments (e.g. for ibuprofen, naproxen, acetaminophen, paroxetine, and hydrochlorothiazide). The antiepileptic drug carbamazepine was the most persistent pharmaceutical and it passed through both the MBR and CAS systems untransformed. Because there was no washout of biomass from the reactor, high-quality effluent in terms of chemical oxygen demand (COD), ammonium content (N-NH(4)), total suspended solids (TSS), and total organic carbon (TOC) was obtained
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