Exploring the destiny and distribution of thiocyanate in the water-soil-plant system and the potential impacts on human health.

Endocrine disruptors like thiocyanate are some of the principal causes of chronic disorders worldwide. Prenatal and postnatal exposure to thiocyanate can interfere with normal neurological development in both fetuses and newborns. Currently, little information regarding thiocyanate levels and potential sources of exposure is available. In this study, we evaluated thiocyanate uptake and accumulation in chard and spinach grown under greenhouse conditions. Both chard and spinach are commonly used to produce baby foods. Three thiocyanate concentrations were compared: Control, T1 (30 ng mL-1), and T2 (70 ng mL-1). Thiocyanate accumulation depended on the concentration and exposure time. Chard was found to accumulate more thiocyanate than spinach, with leaf accumulation > stem accumulation (p < 0.0194) and maximum concentrations of 76 ng g-1 (control), 112 ng g-1, (T1), and 134 ng g-1 (T2). The estimated daily intake (EDI) of thiocyanate for chard and spinach (fresh) exceeded the subchronic reference dose of 200 ng-1 kg-1 day-1 and the chronic reference dose of 600 ng-1 kg-1 day-1. In addition, the EDI of thiocyanate for spinach in baby food exceeded twice the chronic reference dose in the vulnerable newborn-1 year age group. However, all EDIs were lower than the lowest observed adverse effect level (LOAEL) of 1.9 × 105 ng kg-1 day-1. Further studies are needed that increase our knowledge of thiocyanate levels and potential environmental sources to reduce opportunities for exposure, especially in vulnerable groups.

Pliocene-Pleistocene ecological niche evolution shapes the phylogeography of a Mediterranean plant group.

Estimating species ability to adapt to environmental changes is crucial to understand their past and future response to climate change. The Mediterranean Basin has experienced remarkable climatic changes since the Miocene, which have greatly influenced the evolution of the Mediterranean flora. Here, we examine the evolutionary history and biogeographic patterns of two sedge sister species (Carex, Cyperaceae) restricted to the western Mediterranean Basin, but with Pliocene fossil record in central Europe. In particular, we estimated the evolution of climatic niches through time and its influence in lineage differentiation. We carried out a dated phylogenetic-phylogeographic study based on seven DNA regions (nDNA and ptDNA) and fingerprinting data (AFLPs), and modelled ecological niches and species distributions for the Pliocene, Pleistocene and present. Phylogenetic and divergence time analyses revealed that both species form a monophyletic lineage originated in the late Pliocene-early Pleistocene. We detected clear genetic differentiation between both species with distinct genetic clusters in disjunct areas, indicating the predominant role of geographic barriers limiting gene flow. We found a remarkable shift in the climatic requirements between Pliocene and extant populations, although the niche seems to have been relatively conserved since the Pleistocene split of both species. This study highlights how an integrative approach combining different data sources and analyses, including fossils, allows solid and robust inferences about the evolutionary history of a plant group since the Pliocene.

Narrow endemics on coastal plains: Miocene divergence of the critically endangered genus Avellara (Compositae).

Critically endangered species representing ancient, evolutionarily isolated lineages must be given priority when allocating resources for conservation projects. Sound phylogenetic analyses and divergence time estimations are required to detect them, and studies on their population genetics, ecological requirements and breeding system are needed to understand their evolutionary history and to design efficient conservation strategies. Here we present the paradigmatic case of Avellara, a critically endangered monotypic genus of Compositae inhabiting a few swamps in the west-southwest Iberian coastal plains. Our phylogenetic and dating analyses based on nuclear (ITS) and plastid (matK) DNA sequences support a Miocene (>8.6 Ma) divergence between Avellara and closely related genera, resulting in marked morphological and ecological differentiation. We found alarmingly low levels of genetic diversity, based on AFLPs and plastid DNA sequences, and confirmed the prevalence of clonal reproduction. Species distribution modelling suggested a large macroclimatically suitable area for Avellara in the western Iberian Peninsula, but its apparently narrow microecological requirements restrict its distribution to peatlands with low-mineralised waters. Although five populations have been recorded from Spain and Portugal in the past, its current distribution may be reduced to only one population, recurrently found in the last decade but threatened by herbivory and habitat degradation. All this confirms the consideration of Avellara as a threatened species with high phylogenetic singularity, and makes it a flagship species for plant conservation in both Spain and Portugal that should be given priority in the design of in situ and ex situ conservation programmes.

Intoxicación familiar por mercurio elemental: caso clínico / Family poisoned by elemental mercury: a case report

Introduction: mercury is a heavy metal widely dispersed in nature, occurring in three chemical forms. Exposure to mercury at work sites and even at home may be clinically significant. Objective: to update the knowledge about the risks of this toxic element. Case report: the case of a teenager and his family poisoned by elemental mercury is reported. The diagnostic process was difficult, mainly due to an initial presumption of probable infectious etiology, unavailability of key anamnestic data and unusual clinical behavior, with signs and symptoms of multisystem compromise (neurological, hepatic, renal and dermatological compromise). Discussion: the study was based on literature review of various clinical presentations regarding this poisoning and its management, emphasizing the need for dimercaptosuccinic acid chelator. As a major public health problem, the importance of education and implementation of public policies to have a mercury-free environment is discussed.

Introducción: el mercurio es un metal pesado ampliamente distribuido en el medio ambiente, en sus tres formas químicas. La exposición a dicho metal en recintos laborales e incluso en el hogar, puede llegar a ser clínicamente significativa. Objetivo: actualizar el conocimiento acerca de los riesgos de este tóxico. Caso clínico: se presenta el caso clínico de un adolescente y su familia intoxicados por mercurio elemental, cuyo proceso diagnóstico fue difícil, principalmente por la presunción inicial de una probable etiología infecciosa, falta de disponibilidad de datos anamnésticos claves y el inusual comportamiento clínico, con signos y síntomas de compromiso multisistémico (neurológico, hepático, renal y dermatológico). Discusión: se revisa la literatura en relación a las diversas formas de presentación clínica de esta intoxicación y su manejo, destacando la utilidad del quelante ácido dimercaptosuccínico. Por ser un importante problema de salud pública, se destaca la trascendencia de la educación e implementación de políticas públicas por un ambiente libre de mercurio.

Beam width of highly-focused radially-polarized fields.

On the basis of a formal analogy with the irradiance moments, analytical definitions are proposed for the width of both the transverse and the longitudinal component of rotationally-symmetric radially-polarized fields at the focal plane of a high-focusing optical system. The beam width of the whole field is also introduced. The transverse beam size is thus associated with the overall spatial structure of the field. The beam-width definitions are applied to an illustrative example, which enables us to show that, at the focal plane, the power contained within a circle whose radius is given by the proposed beam widths represents the main part of the total power.

Angular momentum decomposition of nonparaxial light beams.

The total angular momentum per unit length of a general non-paraxial beam is decomposed into an orbital component associated with the spiral spectrum at the far field and a component concerning the balance between right- and left-handed circular-polarization content of the angular spectrum. Expressions for the linear momentum and energy per unit length are also provided. The well-known division into orbital and spin components is shown to be recovered in the paraxial limit.

Cross-correlation between spiral modesand its influence on the overall spatial characteristics of partially coherent beams.

The overall spatial structure of a general partially coherent field is shown to be connected with the cross-correlation between the so-called spiral modes, understood as the terms of the spiral-harmonics series expansion of the field. The formalism based on the beam irradiance-moments is used, and the light field is globally described by the beam width, the far-field divergence, the beam quality factor, the orientation of the beam profile and the angular orbital momentum, given as the sum of its asymmetrical and vortex parts. This overall spatial description is expressed in terms of the intermodal coherence features (cross-correlation between spiral modes). The above analytical results are also illustrated by means of an example.

Genuine cross-spectral densities and pseudo-modal expansions.

A necessary and sufficient non-negative definiteness condition for the cross-spectral density (CSD) is provided. It is also shown that any genuine CSD can be expanded in terms of the so-called pseudo-modes of the source, understood as coherent contributions, not orthogonal to one another, that, superposed in an uncorrelated way, give rise to the CSD. Their evaluation is analyzed by means of an illustrative example.

Maximizing Young's fringe visibility under unitary transformations for mean-square coherent light.

Given the values of the degree of polarization of the fields at the pinholes in a Young interferometer, the maximum attainable visibility under unitary transformations is determined when the illuminating beam is mean-square light. Analytical expressions are also obtained for both the field vector (in the mean-square sense) and the cross-spectral density matrix associated with this kind of beams. A comparative summary is also provided of the main characteristics of well-known types of random electromagnetic fields frequently handled in the literature.

Propagation of light fields with radial or azimuthal polarization distribution at a transverse plane.

In terms of the angular spectrum representation, general expressions are given to describe the free-space propagation of electromagnetic fields with radial or azimuthal polarization structure at a transverse plane. The transverse distributions of the radial, azimuthal and longitudinal components of these fields are also analysed. In particular, the on-axis behavior upon free propagation is studied. Furthermore, the special but important case of those fields that retain their polarization character (radial or azimuthal) under propagation is also considered. The analytical results are illustrated by application to some examples.

Evanescent field of vectorial highly non-paraxial beams.

In terms of the Fourier spectrum, a simple but general analytical expression is given for the evanescent field associated to a certain kind of non-paraxial exact solutions of the Maxwell equations. This expression enables one to compare the relative weight of the evanescent wave with regard to the propagating field. In addition, in those cases in which the evanescent term is significant, the magnitude of the field components across the transverse profile (including the evanescent features) can be determined. These results are applied to some illustrative examples.

[Liver biopsy in patients with chronic hepatitis C virus infection: experience in a district hospital]. / Biopsia hepática en pacientes con infección crónica por el VHC: experiencia de un hospital comarcal.

INTRODUCTION: Liver biopsy is a highly useful tool in the evaluation of patients with chronic hepatitis C. However, the technique is not free of complications and presents a series of limitations (lack of representativity and interobserver variability in sample interpretation). Due to these limitations and the development of new noninvasive techniques, the role of liver biopsy is currently being reevaluated. MATERIAL AND METHOD: We performed a descriptive retrospective study of liver biopsies performed in patients with chronic hepatitis C virus (HCV) infection from January 2002 to January 2005. Age, gender, genotype, histology of the hepatic cylinder, and the percentage of patients who received treatment after liver biopsy was analyzed. The indications for biopsy in our patients and the reasons for nontreatment after biopsy were identified. We also analyzed whether the decision to start treatment was influenced by the histological grade of the lesion and whether there is any association between histological grade and transaminase levels. RESULTS: A total of 156 patients were included and 72% received treatment after biopsy. Transaminase levels were elevated in 86%. Alanine aminotransferase (ALT) levels were elevated in 92.30% of treated patients and in 66% of untreated patients. The most frequent cause of nontreatment after biopsy was fibrosis stage < 2. The histological results were as follows: G0 in 2%, G1 in 26.8%, G2 in 47.7%, G3 in 22.2% and G4 in 1.3%; stage of fibrosis was F0 in 7.2%, F1 in 30.1%, F2 in 37.9%, F3 in 19.6%, and F4 in 5.2%. Fibrosis was advanced (F >= 2) in 41% of the patients with normal ALT levels and was mild (< F2) in 33% of those with elevated ALT levels. CONCLUSION: Liver biopsy could be useful in patients with indication for treatment but a high risk of treatment-related adverse effects, as well as in those with normal transaminase levels, in whom the degree of fibrosis observed could influence the therapeutic approach.

[Crohn's disease and pregnancy. A descriptive and retrospective study]. / Enfermedad de Crohn y embarazo: un estudio descriptivo y retrospectivo.

OBJECTIVES: To determine the behavior of Crohn's disease during pregnancy, as well as the influence of this disease on the presence of low birthweight neonates. MATERIAL AND METHODS: A descriptive and retrospective study of all patients with Crohn's disease followed-up in the Hospital Costa del Sol was performed. A total of 124 pregnant women were included, classified in two groups: women who became pregnant before and those who became pregnant after Crohn's disease was diagnosed. In all patients, clinical and epidemiological data, disease activity during pregnancy and in the immediate postpartum period, type of assisted delivery, and neonatal birthweight were recorded. RESULTS: A total of 66.1% of pregnancies occurred before Crohn's disease was diagnosed, 31.5% occurred after diagnosis and 2.4% coincided with disease onset. No significant differences were found between women with and without a diagnosis of Crohn's disease in type of assisted delivery or low birthweight (p = 0.064; p = 0.643). All non-smoking patients remained in the quiescent phase and did not present disease recurrences during pregnancy. Among smokers, the disease remained inactive in 61.1%, while chronic activity or recurrences were observed in 38.9% (p = 0.003). CONCLUSIONS: The course of inflammatory bowel disease does not adversely affect pregnancy or the immediate postpartum period, nor does it increase the presence of low birthweight neonates or the number of cesarean deliveries performed.

On the control of the spatial orientation of the transverse profile of a light beam.

A first-order optical system (represented by its 4x4 ABCD matrix) is given in order to obtain a beam that preserves its spatial orientation of the transverse profile under free propagation from a beam with rotating irradiance distribution in free space. Within the formalism of the second-order irradiance moments, this transverse orientation is analyzed in terms of the evolution of the principal axes of the field irradiance distribution. It is shown that the spatial profile of the beam emerging from the proposed optical system does not rotate when light freely propagates. The improvement of the joint near-field and far-field beam spread product at the output of this optical system is also studied.

On the spatial orientation of the transverse irradiance profile of partially coherent beams.

On the basis of the irradiance-moments formalism, four matrices are proposed whose elements, defined for any partially coherent field, are closely related with the second-order measurable parameters handled in the ISO standard 11146. These matrices are shown to exhibit a number of properties concerning the orientation of the transverse profile of a partially coherent beam. This behavior is described by the rotation of the principal axes of the field around its propagation axis. In addition, these matrices provide information about the spatial structure of the field (beam spread product and orbital part of the angular momentum). A new overall parameter is introduced in terms of the above matrices, which remains invariant under rotation of the Cartesian coordinate axes and upon propagation through rotationally-symmetric first-order optical systems.