1,646 research outputs found

    Phytotoxicity to and uptake of flumequine used in intensive aquaculture on the aquatic weed, Lythrum salicaria L.

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    Phytotoxicity of Flumequine on the aquatic weed Lythrum salicaria L. was determined by two laboratory models: a single concentration test, by which the effects of 100 mg l(-1) were evaluated after 10, 20, 30 days and a multiple concentration test, by which the effects of 5000-1000-500-100-50 mu g l(-1) were evaluated after 35-day exposure. 100 mg l(-1) are highly toxic and significantly decrease the growth of plants; this effect increases with time. Concentrations between 5000 and 50 mu g l(-1) induced hormesis in plants, by significantly increasing mean number and dimension of leaves and secondary roots. The effect is the highest at 50 mu g l(-1) and decreases with increase in concentration. Both toxic effect and hormesis can be related to plant drug uptake, quite high, in the order of mu g g(-1). The ecological implication of Flumequine contamination in aquatic environments and the possible use of Lythrum salicaria for bioremediation and/ or monitoring technique are discussed. (C) 2000 Elsevier Science Ltd. All rights reserved

    An epistatic mini-circuitry between the transcription factors Snail and HNF4a controls liver stem cell and hepatocyte features exhorting opposite regulation on stemness-inhibiting microRNAs

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    Preservation of the epithelial state involves the stable repression of EMT program while maintenance of the stem compartment requires the inhibition of differentiation processes. A simple and direct molecular mini-circuitry between master elements of these biological processes, may provide the best device to keep balanced such complex phenomena. In this work, we show that in hepatic stem cell Snail, a transcriptional repressor of the hepatocyte differentiation master gene HNF4, directly represses the expression of the epithelial microRNAs-200c and -34a, which in turn target several stem cell genes. Notably, in differentiated hepatocytes HNF4, previously identified as a transcriptional repressor of Snail, induces the microRNAs-34a and -200a, b, c that, when silenced, causes epithelial dedifferentiation and reacquisition of stem traits. Altogether these data unveiled Snail, HNF4 and microRNAs -200a, b, c and -34a as epistatic elements controlling hepatic stem cell maintenance/differentiation

    Preliminary Results of the Use of Sowing Time and Variety Choice as Techniques of Adaptability of Durum Wheat (Triticum durum Desf.) to Temperature Increases

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    In the 21st century, global climate change is a key concern for countries all over the world as, in the future, crops will face several extreme events, including an increase of 2–4◦C in the mean temperature with a possible consequent reduction in yield. Wheat (Triticum durum Desf) is one of the most important foods as it provides 20% of the protein for the world population. Since temperature is one of the most limiting factors of crop development, the aim of this trial was to verify the agronomic response of durum wheat to a temperature increase of about 1.5–2.0◦C through the use of short-time adjustment techniques, such as sowing time and variety choice. The experiment foresaw the comparison between two different temperature conditions (ordinary, OT—in the open field, and high, HT—under a polyethylene tunnel), two sowing times (ordinary—OS, and delayed—DS), and three varieties (Ofanto, modern variety; Cappelli, traditional variety; and a mix of the two). HT conditions caused a decline in the wheat yield (−52.5%), but without differences between the two sowing times. The grain quality resulted positively when affected by late sowing times with an increase in 1000 seeds weight and protein percentages and a decrease in shrunken grains. Therefore, it seems that in areas characterized by high temperatures, delayed sowing can improve grain quality without reducing yield quantity compared to ordinary sowing times

    Effects of a medium cut-off (Theranova®) dialyser on haemodialysis patients: a prospective, cross-over study

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    Background. Despite significant advances in haemodialysis (HD) in recent decades, current dialysis techniques are limited by inadequate removal of uraemic solutes such as middle molecules and protein-bound uraemic toxins. Novel medium cut-off (MCO) membrane or \u2018expanded haemodialysis\u2019 (HDx) provides diffusive removal of conventional and large middle molecular weight uraemic toxins, with marginal albumin leak. Methods. This prospective, open-label, controlled, cross-over pilot study compared HDx (novel MCO membrane TheranovaVR 400) and conventional HD in 20 prevalent HD patients. Biochemical, dialysis adequacy and safety measures (adverse events, infections and hospitalization frequency) were recorded. Ten patients underwent conventional HD high-flux dialyser and 10 patients underwent HDx for 3 months, and the patients then switched and received the other treatment for a further 3 months. Results. Treatment with HDx was associated with a significant reduction in serum albumin concentration [median (interquartile range) reduction 0.45 g/dL (0.575 to 0.05); P \ubc 0.025]. However, median albumin levels were 3.5 g/dL and no patients had clinical symptoms of hypoalbuminaemia or needed intravenous albumin administration. The number of infections was lower in patients treated with HDx (n \ubc 7/19) compared with patients treated with HD (n \ubc 14/20; P \ubc 0.03). Patients treated with HDx had reduced levels of interleukin (IL)-1b (from 0.06 6 0.02 pg/mL versus 0.28 6 0.18 pg/mL with HD) and IL-6 (6.45 6 1.57 pg/mL versus 9.48 6 2.15 pg/mL), while tumour necrosis factor-a levels remain unchanged. Conclusions. This study demonstrates that the chronic use of the novel MCO dialyser TheranovaVR appears to be safe and well-tolerated, without serious side effects or hypoalbuminaemia, as well as fewer infections. These results need to be confirmed in larger randomized clinical trials

    MOBILITY AND BIOAVAILABILITY OF HEAVY METALS AND METALLOIDS IN SOIL ENVIRONMENTS

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    In soil environments, sorption/desorption reactions as well as chemical complexation with inorganic and organic ligands and redox reactions, both biotic and abiotic, are of great importance in controlling their bioavailability, leaching and toxicity. These reactions are affected by many factors such as pH, nature of the sorbents, presence and concentration of organic and inorganic ligands, including humic and fulvic acid, root exudates, microbial metabolites and nutrients. In this review, we highlight the impact of physical, chemical, and biological interfacial interactions on bioavailability and mobility of metals and metalloids in soil. Special attention is devoted to: i) the sorption/desorption processes of metals and metalloids on/from soil components and soils; ii) their precipitation and reduction-oxidation reactions in solution and onto surfaces of soil components; iii) their chemical speciation, fractionation and bioavailability

    Yield performance and physiological response of a maize early hybrid grown in tunnel and open air under different water regimes

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    Climate change is one of the most important and studied phenomena of our age and it can have a deep impact on agriculture. Mediterranean countries are and will continue to be strongly affected by changing environmental factors, including lack of precipitation and prolonged heatwaves. The current study aimed to assess the adaptability of an early maize hybrid grown in two temperature conditions and subjected to different irrigation water regimes. The experimen-tal design was a randomized complete-block design with two different temperature conditions: (i) ordinary temperature in open field (OF) and (ii) high temperature (about 3◦ C higher than the current condition) under a poly-ethylene tunnel (PE). In both environments, five irrigation level treatments were applied: 100% (DI100), 75% (DI75), 50% (DI50), 25% (DI25), and 0% restoration of water lost by evapotranspiration (DI0). The responses of maize plants were assessed in terms of yield, nitrogen content determination, nitrogen use efficiency, leaf gas exchanges, and leaf water potential measurements. In both conditions, yield and its components linearly decreased as the irrigation water amount reduced, and even the DI0 plants did not produce. Notably, the PE-DI100 treatment had a significantly higher yield than the corresponding treatment in the open air (9.9 vs. 8.5 t ha−1 ), due mainly to the increased number of ears per square meter (13 vs. 11 m2, respectively). Though, as far as it concerns physiological parameters, a significant effect of environmental conditions was found, with values significantly lower under the protected environment, compared to the plants in the open field. Considering our results, it can be assumed that correct management of amount and time intervals of irrigation could adapt the maize to future climate change

    A performance prediction model for pumps as turbines (PATs)

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    In recent years, the interest towards the use of pumps operating as turbines (PATs) for the generation of electrical energy has increased, due to the low cost of implementation and maintenance. The main issue that inhibits a wider use of PATs is the lack of corresponding characteristic curves, because manufacturers usually provide only the pump-mode performance characteristics. In the PAT selection phase, the lack of turbine-mode characteristic curves forces users to expend expensive and time-consuming efforts in laboratory testing. In the technical literature, numerous methods are available for the prediction of PAT turbine-mode performance based on the pump-mode characteristics, but these models are usually calibrated making use of few devices. To overcome this limit, a performance database called Redawn is presented and the data collected are used to calibrate novel PAT performance models

    Identification of Flavescence dorée-related phytoplasma infecting grapevines on the isle of Ischia (southern Italy)

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    Among the grapevine diseases, Flavescence dorée (FD) is considered to be one of the greatest threats for grapevine cultivation throughout Europe. In Italy, where several major outbreaks of FD have occurred in the past, the disease is still mainly restricted to the northern regions and is under mandatory regulation. In 2011 the disease was recorded for the first time in southern Italy, in several vineyards located on the isle of Ischia (Campania). In order to determine the FD-related phytoplasma infecting these grapevines, molecular investigations were carried out on grapevine samples collected from several FD infected vineyards. The 16S rDNA/spacer region and the FD9 non-ribosomal fragment (secY gene) were investigated using a PCR/RFLP based method; a nucleotide sequence analysis of the FD9 amplified fragments was also carried out. The RFLP profiles obtained from all the analyzed samples showed the presence of FD-D phytoplasma type, on both 16S and secY genomic regions. Sequencing of the FD9 fragments showed a 99 % nucleotide sequence identity among the tested isolates and the various FD-D strains retrieved from the NCBI database.

    Uptake and distribution of lead in tobacco (Nicotiana tabacum L.)

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    Six Nicotiana tabacum varieties were in vitro cultured and experimentally exposed to lead in order to estimate lead uptake and distribution in tobacco plantlets and to observe possible differences depending on variety. Fifty-day-old plantlets were exposed to four Pb rates ranging from 0 to 200 mg dm-3. No statistically significant effect of lead on dry matter weight was observed for any variety or plant part. Tissue lead concentration was determined on upper leaves, lower leaves, stems and roots. Lead accumulation in the plant positively correlated with lead exposure level. Lead concentration in the different plant parts decreased as follows: root, lower leaves, stem and upper leaves. All tobacco varieties showed similar behaviour with respect to lead treatment level and revealed the same distribution pattern of lead concentration in the different plant part. The highest values of tissue lead concentration were found in tobacco variety Pr61, while the lowest in G94-2

    Native Hypovitaminosis D in CKD Patients : From Experimental Evidence to Clinical Practice

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    Native hypovitaminosis D (n-hVITD) is frequently found from the early stages of chronic kidney disease (CKD) and its prevalence increases with CKD progression. Even if the implications of n-hVITD in chronic kidney disease-mineral bone disorder (CKD-MBD) have been extensively characterized in the literature, there is a lot of debate nowadays about the so called "unconventional effects" of native vitamin D (25(OH)VitD) supplementation in CKD patients. In this review, highlights of the dimension of the problem of n-hVITD in CKD stages 2-5 ND patients will be presented. In addition, it will focus on the "unconventional effects" of 25(OH)VitD supplementation, the clinical impact of n-hVITD and the most significant interventional studies regarding 25(OH)VitD supplementation in CKD stages 2-5 ND
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