608 research outputs found

    Sensitivity of freshwater periphytic diatoms to agricultural herbicides

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    The biomonitoring of pesticide pollution in streams and rivers using algae such as diatoms remains difficult. The responses of diatomcommunities to toxic stress in streamwater are disturbed by the variations of environmental parameters. In this study, periphytic algae collected in situwere exposed under controlled conditions to two major herbicides used in French agriculture (isoproturon and s-metolachlor). Three exposure regimes were tested: 5 and 30gL−1 for 6 days and 30gL−1 for 3 days followed by a recovery period of 3 days. The algal biomasses were assessed from pigment concentrations (chlorophyll a and c) and from live cell density. The highest concentration (30gL−1) of isoproturon inhibited the biomass increase statistically significantly. In periphyton exposed to 5 and 30gL−1 of s-metolachlor, chlorophyll c concentration and live cell densitywere also statistically significantly lower than in the control. Periphyton left to recover after reduced exposure duration (3 days) showed higher growth rates after treatment with s-metolachlor than with isoproturon. Taxonomic identifications showed that species like Melosira varians, Nitzschia dissipata and Cocconeis placentula were not affected by the herbicide exposure. Other species like Eolimna minima and Navicula reichardtiana were more sensitive. Studying diatoms according to their trophic mode showed that facultative heterotroph specieswere statistically significantly favoured by isoproturon exposure at the highest concentration. Results obtained with s-metolachlor exposure showed a disturbance of cell multiplication rather than that of photosynthesis. These results suggest that photosynthesis inhibitors like isoproturon favour species able to survive when the autotroph mode is inhibited

    The melanin pigmentation: cellular and biomolecular mechanisms

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    Several factors are determinant for the color of human skin: the thickness of the stratum corneum, the speed of blood flow, the degree of oxygenation of hemoglobin but the main role is played by the presence of pigments such as carotenoids and, above all, melanin. The amount and the type of melanin is genetically determined, but they are strongly influenced by the other conditions such as hormonal and environmental: age, presence of metal ions, and inflammatory processes, and specifically exposure to sunlight. In vertebrates, melanocytes cells, responsible for the production of melanin, have the main function, but not exclusively, to protect the skin from the genotoxic stress produced by ultraviolet rays (UV); melanin absorbs the UV and neutralizers reactive oxygen species (ROS) they produce. Some studies clarified, at least in part, enzymatic and non enzymatic factors involved in the biosynthesis of melanin and the molecular mechanisms underlying the different responses of skin pigmentation to external stimuli, particularly to solar radiation. In this review we want to revise the cellular and biochemical aspects of skin pigmentation

    Deformed Pleistocene marine terraces along the Ionian sea margin of southern Italy: unveiling blind fault-related folds contribution to coastal uplift

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    Morphotectonic analysis and fault numeric modeling of uplifted marine terraces along the Ionian Sea coast of the Southern Apennines allowed us to place quantitative constraints on middle Pleistocene-Holocene deformation. Ten terrace orders uplifted to as much as +660 m were mapped along ~80 km of the Taranto Gulf coastline. The shorelines document both a regional and a local, fault-induced contribution to uplift. The intermingling between the two deformation sources is attested by three 10 km scale undulations superimposed on a 100 km scale northeastward tilt. The undulations spatially coincide with the trace of NW-SE striking transpressional faults that affected the coastal range during the early Pleistocene. To test whether fault activity continued to the present, we modeled the differential uplift of marine terraces as progressive elastic displacement above blind oblique-thrust ramps seated beneath the coast. Through an iterative and mathematically based procedure, we defined the best geometric and kinematic fault parameters as well as the number and position of fault segments. Fault numerical models predict two fault-propagation folds cored by blind thrusts with slip rates ranging from 0.5 to 0.7 mm/yr and capable of generating an earthquake with a maximum moment magnitude of 5.9–6.3. Notably, we find that the locus of predominant activity has repeatedly shifted between the two fault systems during time and that slip rates on each fault have temporally changed. It is not clear if the active deformation is seismogenic or dominated by aseismic creep; however, the modeled faults are embedded in an offshore transpressional belt that may have sourced historical earthquakes

    Localizationof the 5S and 45S rDNA sites and CPDNA sequence analysis in species of the quadrifaria group of Paspalum (Poaceae, Panicae).

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    The Quadrifaria group of Paspalum (Poaceae, Paniceae) comprises species native to the subtropical and temperate regions of South America. The purpose of this research was to characterize the I genomes in five species of this group and to establish phylogenetic relationships among them. Prometaphase chromatin condensation patterns, the physical location of 5S and 45S rDNA sites by fluorescence in situ hybridization (FISH), and sequences of five chloroplast non-coding regions were analysed. The condensation patterns observed were highly conserved among diploid and tetraploid accessions studied and not influenced by the dyes used or by the FISH procedure, allowing the identification of almost all the chromosome pairs that carried the rDNA signals. The FISH analysis of 5S rDNA sites showed the same localization and a correspondence between the number of sites and ploidy level. In contrast, the distribution of 45S rDNA sites was variable. Two general patterns were observed with respect to the location of the 45S rDNA. The species and cytotypes Paspalum haumanii 2x, P. intermedium 2x, P. quadrifarium 4x and P. exaltatum 4x showed proximal sites on chromosome 8 and two to four distal sites in other chromosomes, while P. quarinii 4x and P. quadrifarium 2x showed only distal sites located on a variable number of small chromosomes and on the long arm of chromosome 1. The single most-parsimonious tree found from the phylogenetic analysis showed the Quadrifaria species partitioned in two clades, one of them includes P. haumanii 2x and P. intermedium 2x together with P. quadrifarium 4x and P. exaltatum 4x, while the other contains P. quadrifarium 2x and P. quarinii 4x. The subdivision found with FISH is consistent with the clades recovered with cpDNA data and both analyses suggest that the Quadrifaria group, as presently defined, is not monophyletic and its species belong in at least two clades

    Acne radar: A new intuitive graphic visualization of quality of life in acne patients

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    Background: There are many instruments available in literature to evaluate the influence of acne on Qualify of Life (QoL), but many of these questionnaires rarely are performed in daily clinical practice. Many of these instruments require a long time for the compilation, and often they are not self completed. There are no simple and intuitive instrument that can be completed by patients alone, with a graphical representation of the results. Objective: To develop a new, rapid and intuitive graphic instrument to a questionnaire allowing both a quick assessment of the impact of acne on patients and, at the same time, increase patient's compliance and self-esteem. Methods: In our study 50 patients were recruited and questionnaire was administered following the main items evaluated in the validated index of QoL from previous studies for acne patients. We have applied an intuitive graph representation, the "Radar Graph", and other statistical methods like the Decisional Map and the Principal Component Analysis, to this questionnaire allowing a quick assessment of the impact of acne on patients. Results: The questionnaire evaluated have 10 items regarding 3 different area: the objective symptoms such as negative perception of their image (imperfection), sting and insomnia; the subjective symptoms such as depression, perception of illness, lack of serenity and shame; and the relational difficulties such as social relationships, working relationships, and intimate relations. The answers are given on a 10-point visual analogue scale. Conclusion: Our survey can be a new, rapid and intuitive graphic instrument to use in clinical practice

    A new classification and clinical predictivity for some naevus variants

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    Background. The incidence of cutaneous melanoma is rapidly increasing in Europe. Active research is directed toward the identification of naevi as a risk factor. Objective. The aim of our case-control study was to observe different numbers of moles and different mole typology associations in order to evaluate clinical predictivity and to establish a new classification for some naevus variants. Methods. A case-control study was carried out, enrolling 64 cases affected by melanoma and 183 controls, between October 2009 and February 2011. Each patient was interviewed and subjected to clinical examination. The resulting data were analysed using the statistical elaboration program SPSS 16.0. Results. The association of target naevus with other variants increases the degree of risk (target + small brown Odds Ratio 5.25; confidence interval 1.8-15.4); (target + small brown + small black + large brown odds ratio 5.0; confidence interval 1.1-22.4). Therefore, other variants and/or other variant combinations do not significantly increase risk. Conclusion. People presenting two naevus variants in association with other naevus variants seem to run a major risk. The general nonuniformity of the whole naevus panorama should be carefully considered

    Teledermatology: From Prevention to Diagnosis of Nonmelanoma and Melanoma Skin Cancer

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    Telemedicine is a rapidly developing application of clinical medicine where medical information is transferred through interactive audiovisual media for the purpose of consulting remote medical procedures or examinations, reducing the time of consultation for patients. Teledermatology as an application of telemedicine was developed in 1995: it turns out to be a gradually more ordinary mean of delivering dermatologic healthcare worldwide and will almost certainly have a greater medical function in the future. In particular, teledermatology can aid in the prevention and diagnosis of nonmelanoma and melanoma skin cancer; telemedicine and teledermatology offer the opportunity to make available consultations with experts also by long distance. Overall, patients seem to accept teledermatology, considering it as an excellent mean to obtain healthcare, particularly in those areas with no expert dermatologists available. Clinicians have also generally reported affirmative experiences with teledermatology in the skin cancer field. Further studies focusing on cost effectiveness, patient outcomes, and patient and clinician satisfaction will facilitate to delineate the potential of teledermatology as a mean of prevention and diagnosis of nonmelanoma and melanoma skin cancer

    Discussion on how to implement a verbal scale in a forensic laboratory: benefits, pitfalls and suggestions to avoid misunderstandings

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    In a recently published guideline for evaluative reporting in forensic science, the European Network of Forensic Science Institutes (ENFSI) recommended the use of the likelihood ratio for the measurement of the value of forensic results. As a device to communicate the probative value of the results, the ENFSI guideline mentions the possibility to define and use a verbal scale, which should be unified within a forensic institution. This paper summarizes discussions held between scientists of our institution to develop and implement such a verbal scale. It intends to contribute to general discussions likely to be faced by any forensic institution that engages in continuous monitoring and improving of their evaluation and reporting format. We first present published arguments in favour of the use of such verbal qualifiers. We emphasize that verbal qualifiers do not replace the use of numbers to evaluate forensic findings, but are useful to communicate the probative value, since the weight of evidence in terms of likelihood ratio are still apprehended with difficulty by both the forensic scientists, especially in absence of hard data, and the recipient of information. We further present arguments that support the development of the verbal scale we propose. Recognising the limits of the use of such a verbal scale, we then discuss its disadvantages: it may lead to the spurious view according to which the value of the observations made in a given case is relative to other cases. Verbal qualifiers are also prone to misunderstandings and cannot be coherently combined with other evidence. We therefore recommend not using the verbal qualifier alone in a written statement. While scientists should only report on the probability of the findings - and not on the probability of the propositions, which are the duty of the Court - we suggest showing examples to let the recipient of information understand how the scientific evidence affects the probabilities of the propositions. To avoid misunderstandings, we also advise to mention in the statement what the results do not mean. Finally, we are of the opinion that if experts were able to coherently articulate numbers, and if recipients of information could properly handle such numbers, then verbal qualifiers could be abandoned completely. At that time, numerical expressions of probative value will be appropriately understood, as other numerical measures that most of us understand without the need of any further explanation, such as expressions for length or temperature

    A New Classification and Clinical Predictivity for Some Naevus Variants

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    Background. The incidence of cutaneous melanoma is rapidly increasing in Europe. Active research is directed toward the identification of naevi as a risk factor. Objective. The aim of our case-control study was to observe different numbers of moles and different mole typology associations in order to evaluate clinical predictivity and to establish a new classification for some naevus variants. Methods. A case-control study was carried out, enrolling 64 cases affected by melanoma and 183 controls, between October 2009 and February 2011. Each patient was interviewed and subjected to clinical examination. The resulting data were analysed using the statistical elaboration program SPSS 16.0. Results. The association of target naevus with other variants increases the degree of risk (target + small brown Odds Ratio 5.25; confidence interval 1.8–15.4); (target + small brown + small black + large brown odds ratio 5.0; confidence interval 1.1–22.4). Therefore, other variants and/or other variant combinations do not significantly increase risk. Conclusion. People presenting two naevus variants in association with other naevus variants seem to run a major risk. The general nonuniformity of the whole naevus panorama should be carefully considered

    “Il Corpo Ritrovato”: Dermocosmetological Skin Care Project for the Oncologic Patient

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    Neoplastic disease and its therapeutic options have a huge impact on the patient's quality of life from both the emotional and the working point of view. The project “Il Corpo Ritrovato” aims at creating an interdisciplinary network of physicians to improve the quality of life of the oncologic patient, focusing on such important aspects as dermocosmetological skin care but also on the evaluation of new therapeutic and diagnostic algorithms in order to make further progress in the field of prevention
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