A pesticide monitoring study covering the main rivers and lakes of Northern Greece (Macedonia, Thrace and Thessaly) was undertaken. A total of 416 samples were collected over a 1.5-year sampling ...period (September 1999– February 2001) from six rivers and ten lakes. The water samples were analyzed with an off-line solid phase extraction technique coupled with a gas chromatography ion trap mass spectrometer using an analytical method for 147 pesticides and their metabolites, including organochlorines, organophosphates, triazines, chloroacetanilides, pyrethroids, carbamates, phthalimides and other pesticides (herbicides, insecticides and fungicides). Based on the pesticide survey results, a human health carcinogenic and non-carcinogenic risk assessment was conducted for adults and children. Ecotoxicological risk assessment was also conducted using default endpoint values and the risk quotient method. Results showed that the herbicides metolachlor, prometryn, alachlor and molinate, were the most frequently detected pesticides (29%, 12.5%, 12.5% and 10%, respectively). They also exhibited the highest concentration values, often exceeding 1μg/L. Chlorpyrifos ethyl was the most frequently detected insecticide (7%). Seasonal variations in measured pesticide concentrations were observed in all rivers and lakes. The highest concentrations were recorded during May–June period, right after pesticide application. Concentrations of six pesticides were above the maximum allowable limit of 0.1μg/L set for drinking water. Alachlor, atrazine and a-HCH showed unacceptable carcinogenic risk estimates (4.5E-06, 4.6E-06 and 1.3E-04, respectively). Annual average concentrations of chlorpyriphos ethyl (0.031μgL), dicofol (0.01μg/L), dieldrin (0.02μg/L) and endosulfan a (0.065μg/L) exceeded the EU environmental quality standards. The risk quotient estimates for the insecticides chorpyrifos ethyl, diazinon and parathion methyl and herbicide prometryn were above acceptable risk values. The coupling of monitoring data to probabilistic human and ecotoxicological risk estimates could find use by Greek regulatory authorities, proposing effective pollution management schemes.
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•Pesticides in rivers of north Greece posed low potential non-carcinogenic risk.•Carcinogenic risk caused by a metabolite was higher than the parametric value.•High ecotoxicological risk for four pesticides was observed (Risk Quotient approach)•Six pesticides were detected at concentrations higher than 0.1μgL−1.•Herbicides comprised the vast majority of the detected pesticides.
The occurrence and fate of carbonyl compounds as ozonation by-products at a full scale drinking water treatment plant (DWTP) were studied for one year. Raw water and samples after the main treatment ...processes (pre-ozonation, coagulation/flocculation, sand filtration, main ozonation, filtration through granular activated carbon and chlorination) were collected on a monthly basis. Pre-ozonation led to the formation of carbonyl compounds at concentrations of 67.3±43.3μg/l as sum of 14 carbonyl compounds whereas lower concentrations were determined after the main ozonation process, 32.8±22.3μg/l. The dominant compounds were formaldehyde, acetaldehyde, glyoxal and methyl glyoxal contributing to 65% of total carbonyl content. The DOC reactivity in formation of carbonyl compounds varied through the year exhibiting the higher values in spring. Coagulation/flocculation and sand filtration significantly removed (64–80%) the carbonyl compounds formed at the pre-ozonation step. The removal efficiency of filtration through granular activated carbon showed great variation ranging from 15 to 62%. Finally, the concentrations of carbonyl compounds in finished water were low, close to detection limits, revealing the efficiency of DWTP in the removal of this class of ozonation by-products.
•Fate of ozonation by-products at DWTP•For, Ace Gly and MGly are the dominant compounds.•The post-ozonation filtration processes effectively remove ozonation DBPs.•Seasonal changes in DOC reactivity
Magnetic resonance (MR) guided high intensity focused ultrasound and external beam radiotherapy interventions, which we shall refer to as beam therapies/interventions, are promising techniques for ...the non-invasive ablation of tumours in abdominal organs. However, therapeutic energy delivery in these areas becomes challenging due to the continuous displacement of the organs with respiration. Previous studies have addressed this problem by coupling high-framerate MR-imaging with a tracking technique based on the algorithm proposed by Horn and Schunck (H and S), which was chosen due to its fast convergence rate and highly parallelisable numerical scheme. Such characteristics were shown to be indispensable for the real-time guidance of beam therapies. In its original form, however, the algorithm is sensitive to local grey-level intensity variations not attributed to motion such as those that occur, for example, in the proximity of pulsating arteries. In this study, an improved motion estimation strategy which reduces the impact of such effects is proposed. Displacements are estimated through the minimisation of a variation of the H and S functional for which the quadratic data fidelity term was replaced with a term based on the linear L1norm, resulting in what we have called an L2-L1 functional. The proposed method was tested in the livers and kidneys of two healthy volunteers under free-breathing conditions, on a data set comprising 3000 images equally divided between the volunteers. The results show that, compared to the existing approaches, our method demonstrates a greater robustness to local grey-level intensity variations introduced by arterial pulsations. Additionally, the computational time required by our implementation make it compatible with the work-flow of real-time MR-guided beam interventions. To the best of our knowledge this study was the first to analyse the behaviour of an L1-based optical flow functional in an applicative context: real-time MR-guidance of beam therapies in moving organs.
In this paper, we propose a variational formulation for histogram transfer of two or more color images. We study an energy functional composed by three terms: one tends to approach the cumulative ...histograms of the transformed images, the other two tend to maintain the colors and geometry of the original images. By minimizing this energy, we obtain an algorithm that balances equalization and the conservation of features of the original images. As a result, they evolve while approaching an intermediate histogram between them. This intermediate histogram does not need to be specified in advance, but it is a natural result of the model. Finally, we provide experiments showing that the proposed method compares well with the state of the art.
The phase, as well as the magnitude, of MRI images can carry useful information. It may be used to encode flow or temperature, or to map the magnetic field for the undistorting of EPIs and automated ...shimming. In all cases, we measure the extra spin given to nuclei. Unfortunately, we can only measure the final phase of the spins: the rotation is wrapped into the range −π, +π, and to obtain a measure of the parameter of interest the missing multiples of 2π must be replaced—a process known as phase unwrapping. While simple in principle, standard phase unwrapping algorithms fail catastrophically in the presence of even small amounts of noise. Here we present a new algorithm for robust three-dimensional phase unwrapping, in which unwrapping is guided, so that it initially works on less noisy regions. We test the algorithm on simulated phase data, and on maps of magnetic field, which were then used to successfully undistort EPI images. The unwrapping algorithm could be directly applied to other kinds of phase data.
The quantum mechanical motion of electrons and nuclei in systems spatially confined to the molecular dimensions occurs on the sub-femtosecond to the femtosecond timescales respectively. Consequently, ...the study of ultrafast electronic and, in specific cases, nuclear dynamics requires the availability of light pulses with attosecond (asec) duration and of sufficient intensity to induce two-photon processes, essential for probing the intrinsic system dynamics. The majority of atoms, molecules and solids absorb in the extreme-ultraviolet (XUV) spectral region, in which the synthesis of the required attosecond pulses is feasible. Therefore, the XUV spectral region optimally serves the study of such ultrafast phenomena. Here, we present a detailed review of the first 10-GW class XUV attosecond source based on laser driven high harmonic generation in rare gases. The pulse energy of this source largely exceeds other laser driven attosecond sources and is comparable to the pulse energy of femtosecond Free-Electron-Laser (FEL) XUV sources. The measured pulse duration in the attosecond pulse train is 650 ± 80 asec. The uniqueness of the combined high intensity and short pulse duration of the source is evidenced in non-linear XUV-optics experiments. It further advances the implementation of XUV-pump-XUV-probe experiments and enables the investigation of strong field effects in the XUV spectral region.
The factorial-additive optimality of primes, i.e., that the sum of prime factors is always minimum, implies that prime numbers are a solution to an integer linear programming (ILP) encoding ...optimization problem. The summative optimality of primes follows from Goldbach’s conjecture, and is viewed as an upper efficiency limit for encoding any integer with the fewest possible additions. A consequence of the above is that primes optimally encode—multiplicatively and additively—all integers. Thus, the set P of primes is the unique, irreducible subset of ℤ—in cardinality and values—that optimally encodes all numbers in ℤ, in a factorial and summative sense. Based on these dual irreducibility/optimality properties of P, we conclude that primes are characterized by a universal “quantum type” encoding optimality that also extends to non-integers.
Depression prevalence increases significantly during adolescence/early adulthood. Depression in youth may present suicidal ideation, while suicide represents the leading cause of death in this age ...group. Moreover, adolescents/young adults frequently report sleep complaints that may partially be due to depressive symptoms. Studies on the associations between depression, sleep complaints and suicidality in this age group are limited. We aimed to examine associations between depressive symptoms, sleep complaints and suicidal ideation in a large (n = 2771), representative sample of adolescents (age: 15-17 years, n = 512) and young adults (age: 18-24 years, n = 2259) from the general population in Greece. A telephone structured questionnaire was administered. Depressive symptoms were assessed using the modified Patient Health-7 questionnaire score, while presence of suicidal ideation and sleep complaints were assessed using the ninth and third question of Patient Health-9 questionnaire, respectively. Mediation logistic regression analysis revealed significant direct paths from depressive symptoms to sleep complaints (odds ratio OR 1.22, 95% confidence interval CI 1.19-1.24; OR 1.21, 95% CI 1.18-1.24) and suicidal ideation (OR 1.18, 95% CI 1.14-1.22; OR 1.18, 95% CI 1.14-1.22), as well as sleep complaints and suicidal ideation (OR 1.82, 95% CI 1.32-2.50; OR 1.91, 95% CI 1.33-2.76) in the total group and in young adults, respectively, but not among adolescents. Moreover, we detected a significant indirect effect of depressive symptoms on suicidal ideation mediated by sleep complaints (18.8%) in young adults. These findings support the hypothesis that treatment of sleep disturbances among youth with depression may independently further reduce suicidal risk.
Galactosemia is an inherited disorder caused by mutations in the three genes that encode enzymes implicated in galactose catabolism. Currently, the only available treatment for galactosemia is ...life-long dietary restriction of galactose/lactose, and despite treatment, it might result in long-term complications.
Here, we present five cases of newborn patients with elevated galactose levels, identified in the context of the newborn screening program. Genetic analysis concerned a next generation sequencing (NGS) methodology covering the exons and adjacent splice regions of the
,
, and
genes.
Our approach led to the identification of eight rare nonsynonymous DNA variants. Four of these variants, namely, p.Arg204Gln and p.Met298Ile in
, p.Arg68Leu in
, and p.Ala180Thr in
, were already recorded in relevant databases, yet their clinical significance is uncertain. The other four variants, namely, p.Phe245Leu in
, p.Gly193Glu in
, and p.Ile266Leu and p.Ala216Thr in the
gene, were novel.
analysis of the possible effect of these variants in terms of protein function and stability was performed using a series of bioinformatics tools, followed by visualization of the substituted amino acids within the protein molecule. The analysis revealed a deleterious and/or destabilizing effect for all the variants, supported by multiple tools in each case.
These results, given the extreme rarity of the variants and the specific phenotype of the respective cases, support a pathogenic effect for each individual variant. Altogether, our study shows that targeted NGS methodologies may offer a time- and cost-effective approach for the genetic investigation of galactosemia and can assist in elucidating the complex genetic background of this disorder.
Tensile test were carried out on glass/polypropylene specimens made in-home, and acoustic emissions were recorded from these tests. Fibre orientation of each specimen was different in order to obtain ...preferred failure modes. The hypothesis is that each micro mechanical event will have one distinctive waveform as fingerprint. In order to differentiate the waveforms the primarily frequency is plotted on a power spectrum graph by means of a Fast Fourier Transformation. The primarily frequency from each power spectrum is then plotted against progress of test. The resulting graph showed clusters around well-defined frequencies. From the results it can be observed the existence of a relation between micro mechanical events and specific frequencies.
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