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Monitoring mercury in two South African herbariaKataeva, M, Panichev, N, van Wyk, EA 02 December 2008 (has links)
Abstract
Mercury [Hg] emissions from old plant collections treated with mercuric chloride (HgCl2) may
present a high health risk for staff working in certain herbaria. The present study evaluated
Hg concentrations in ambient air, plant specimens and biological samples from staff working
in the Pretoria National Herbarium (PRE) and the H.G.W.J. Schweickerdt Herbarium (PRU),
University of Pretoria. Biological samples from a group of 15 people exposed to HgCl2 in
herbaria and a non-exposed control group of five people were studied. Additionally, plant
samples from herbarium specimens treated and non-treated with HgCl2 were analysed.
Plant materials treated with HgCl2 had persistent high concentrations of Hg in the range of
114–432 μg g−1, whereas untreated materials were in the range of 0.20–0.45 μg g−1. The HgCl2-
treated plant specimens induced elevated concentrations of Hg into the herbarium rooms
near storage cabinets, where up to 1 μg m−3 of Hg was measured in the air of both herbaria.
However, no significant difference in mean Hg concentrations in hair was found between
herbarium workers and members of the control group, 0.46 and 0.64 μg g−1 respectively
(p<0.05, Student's t-test). For both groups, Hg concentrations were lower than that indicated
by the World Health Organization [WHO] for non-exposed adults, namely 2 μg g−1. The mean
concentration of total Hg in urine from the mercury-exposed herbarium group, 2.28 μg g−1
creatinine, was significantly higher than in the control group, 1.05 μg g−1 of creatinine. For
both populations, the concentrations of Hg in their urine were below the threshold Hg values
set by the WHO, i.e., 5 μg g−1 creatinine. We concluded that there was no strong response by
individual herbarium staff from long-term exposure to Hg concentrations in the range of 0.28–1.1 μg m−3.
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Monitoring mercury in two South African herbariaKataeva, M, van Wyk, AE, Panichev, N 02 December 2008 (has links)
Abstract
Mercury [Hg] emissions from old plant collections treated with mercuric chloride (HgCl2) may
present a high health risk for staff working in certain herbaria. The present study evaluated
Hg concentrations in ambient air, plant specimens and biological samples from staff working
in the Pretoria National Herbarium (PRE) and the H.G.W.J. Schweickerdt Herbarium (PRU),
University of Pretoria. Biological samples from a group of 15 people exposed to HgCl2 in
herbaria and a non-exposed control group of five people were studied. Additionally, plant
samples from herbarium specimens treated and non-treated with HgCl2 were analysed.
Plant materials treated with HgCl2 had persistent high concentrations of Hg in the range of
114–432 μg g−1, whereas untreated materials were in the range of 0.20–0.45 μg g−1. The HgCl2-
treated plant specimens induced elevated concentrations of Hg into the herbarium rooms
near storage cabinets, where up to 1 μg m−3 of Hg was measured in the air of both herbaria.
However, no significant difference in mean Hg concentrations in hair was found between
herbarium workers and members of the control group, 0.46 and 0.64 μg g−1 respectively
(p<0.05, Student's t-test). For both groups, Hg concentrations were lower than that indicated
by the World Health Organization [WHO] for non-exposed adults, namely 2 μg g−1. The mean
concentration of total Hg in urine from the mercury-exposed herbarium group, 2.28 μg g−1
creatinine, was significantly higher than in the control group, 1.05 μg g−1 of creatinine. For
both populations, the concentrations of Hg in their urine were below the threshold Hg values
set by the WHO, i.e., 5 μg g−1 creatinine. We concluded that there was no strong response by
individual herbarium staff from long-term exposure to Hg concentrations in the range of
0.28–1.1 μg m−3.
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Plantarum novarum ex Herbario Sprengelii centuriamBiehler, Johann Friedrich Theodor. Sprengel, Kurt Polycarp Joachim, January 1900 (has links)
Thesis--1807. / Title from screen, viewed 8 April 2008. Creation of machine-readable version: Phil Garnock-Jones. Conversion to TEI.2-conformant markup: Jamie Norrish. Originally published in print: Halis Saxonum : F.A. Grunerti Patr., 1807.
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Evaluación de los efectos de dos extractos estandarizados de Serenoa repens, sobre la hiperplasia prostática benigna en el perroGarcía Cabrera, Renato Orlando January 2004 (has links)
Memoria para optar al Título
Profesional de Médico Veterinario / Con el propósito de estudiar la eficacia clínica y el efecto histopatológico de dos extractos lipoesterólicos de Serenoa repens (ELSR) y acetato de megestrol (AM) sobre la hiperplasia prostática benigna canina (HPB), se utilizaron 21 perros de raza ovejero alemán, con un rango de edad entre los 3 y 11 años, divididos en tres grupos de 7 animales cada uno, los cuales recibieron dos dosis distintas de ELSR y AM respectivamente. El criterio de selección incluyó un examen clínico mediante la palpación rectal, examen ecotomográfico y evaluación histopatológica del tejido prostático biopsiado mediante guía ecográfica
Una vez finalizado el tratamiento de ocho semanas para los grupos que recibieron el ELSR y de 30 días para el AM, todos los grupos mostraron diferencias significativas en relación a las mediciones previas al tratamiento, tales como, morfometría prostática ecotomográfica, altura acinar prostática y evidencia de la reducción de la sintomatología asociada a la HPB
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Atividade antiulcerogenica de alcaloides pirrolizidinicos obtidos a partir do extrato etanolico de senecio brasiliensis : perspectivas de uma nova terapeutica preventiva e curativa das ulceras gastricas e duodenaisToma, Walber 12 December 2003 (has links)
Orientador: Alba Regina Monteiro Souza Brito / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-03T21:51:03Z (GMT). No. of bitstreams: 1
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Previous issue date: 2003 / Resumo: Senecio brasiliensis é uma planta nativa da América do Sul e comumente encontrada no Brasil. Populannente é conhecida como Margaridinha, Flor-das-Almas, Tasneirinha e é muito utilizada pela medicina popular para o tratamento de dores estomacais. Estudos fitoquímicos relatam a presença de Alcalóides PiITolizidinicos (P As) em Senecio brasiliensis. Este estudo tem portanto como objetivo isolar e avaliar a atividade antiulcerogênica doS" P As em modelos tradicionais de indução de úlceras gástricas e duodenais em roedores. Além disso, enfatiza também o(s) provável(eis) mecanismo(s) de ação antiulcerogênico dos PAs. Os resultados obtidos demonstram que os PAs apresentam eficácia antiulcerogênica gástrica e duodenal, bem como demonstra mecaniSmos farmacológicos que evidenciam mna cicatrização das lesões com caráter não apenas quantitativo, mas também qualitativo, sendo portanto provável protótipo de droga com grandes perspectivas futuras no combate aos males das lesões gástricas e duodenais / Abstract: Senecio brasiliensis is a native plant from South América and is found mainly in Brazil. Popularly Senecio is knowed as Margaridinha, Flor-das-Almas, Tasneirinha and is very utilized by foIk medicine to the treatment of gastrointestinal diseases. Phytochemical analysis showed the presence of Pyrrolizidine AIkaloids (P As) from Senecio brasiliensis. This study have a objective the obtained of P As extract and evaluated the antiulcerogenic activity of the P As on standard rodent models. Furthermore this study also evaluated the probably pharmacological mechanism(s) ofthe PAs. The results showed the antiulcerogenic activity on gastric and duodenal induced ulcerogenic lesions. The pharmacological mechanisms showed that P As can be a quantitative and probably qualitative antiulcerogenic activity. P As, therefore is a probably therapy alterna tive in the future. News assays are necessary to determina te the efficacy and safety of this drug / Doutorado / Doutor em Farmacologia
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Salud y enfermedad en un contexto Intercultural. — Un acercamiento a partir del caso mapuche en el consultorio poniente de PudahuelWinkler Sotomayor, Lisette January 2010 (has links)
No description available.
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Effects of climate change and other anthropogenic impacts on plant phenology and wildlife health in North AmericaMiller, Tara King 19 September 2023 (has links)
Plants and wildlife are being affected by climate change and human activities. We need to understand the patterns in these impacts to develop management strategies and policy solutions that will help us conserve ecosystems. Climate change is shifting the timing of key life stages in plants, but we do not fully understand the extent and implications of phenological shifts – or changes in the timing of seasonal events – for understudied stages like fruiting or for potential mismatches between plants in different canopy levels. Human activities and climate change impact and harm wildlife in many ways, from wildlife-vehicle collisions and lead poisoning to hurricanes and infectious diseases, but it has been difficult to form a comprehensive picture of these threats across many species and regions, and to discern which factors pose the greatest threat to at-risk species. Here, I collected and curated data from herbarium specimens and wildlife rehabilitation records to advance our understanding of the effects of climate change and human activities on plants and wildlife in North America. First, I found that metrics of first, peak, and last fruiting dates were strongly correlated between two historical datasets, suggesting that field observations and herbarium collections capture similar orders of fruiting times among plant species in New England. However, I found differences in the exact timing of first and last fruiting dates, indicating that researchers should match methodology when selecting historical records of phenology for present-day comparisons, especially when the exact timing is important. Next, I found that native trees, native shrubs, and non-native shrubs advanced their leaf-out or flowering times faster than native wildflowers advanced their flowering times with warming temperatures. As climate warming progresses, some native wildflower species, especially in warmer regions, are likely to be affected by phenological mismatch and lose access to early-season sunlight. Last, I found that human disturbances accounted for the largest proportion of wildlife injury and sickness in animals admitted to wildlife rehabilitation centers, and I identified the predominant reason for admittance for many species; these reasons included vehicle collisions, fishing incidents, and window or building collisions. I recommended possible interventions to help conserve wildlife, including using or changing wildlife road crossings, fishing and hunting regulations, lead and pesticide regulations, and disaster management plans. In this research, I compiled and analyzed innovative, newly-digitized data sources to provide new insights into the effects of climate change and human activities on plants and wildlife in North America. / 2024-09-18T00:00:00Z
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A Historical Floristic Inventory of Pine Rockland Fabaceae (Leguminosae)Pena, Adel L 15 November 2017 (has links)
The objectives of this study were to investigate temporal changes in the diversity of pine rockland Fabaceae, induced by anthropogenic factors. Herbarium collections spanning 170 years were used to analyze species frequency and richness. The results indicated temporal fluctuations in diversity with frequency of native species highest previous to the year 1920, and exotic-invasive species richness peaking after the 1960s. The accompanying species list resulting from the inventory included 122 Fabaceae species, in 56 genera, with an additional 19 species not previously listed for pine rocklands. The results emphasize the damage caused by early and deliberate introductions of exotic species, and reinforces previous knowledge that exotic-invasives seem to be increasingly harmful to local biodiversity. The results also provide evidence of the historical distribution of species, helpful to conservation and restoration efforts. This study provides a needed review and status update for the Fabaceae taxa of the pine rocklands.
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Bioaccumulation et bioindication par les lichens de la pollution atmosphérique actuelle et passée en métaux et en azote en France : sources, mécanismes et facteurs d'influence / Bioaccumulation and bioindication by lichens of the current and historical atmospheric pollution of metals and nitrogen in France : sources, mechanisms and influencing factorsAgnan, Yannick 29 November 2013 (has links)
La contamination atmosphérique par les métaux/métalloïdes (As, Cd, Cu, Pb, Sb, Zn…) et par les composés azotés impacte durablement les écosystèmes. L’évaluation des dépôts atmosphériques responsables de ces effets néfastes reste éparse car complexe, en particulier dans les environnements éloignés des sources de contamination comme les massifs forestiers. La prospection et l’estimation des éléments traces et de l’azote apportés dans ces dépôts ont été réalisées à l’échelle nationale à travers deux approches de biosurveillance par les lichens et les mousses : la bioaccumulation et la bioindication. L’enregistrement des éléments traces par les organismes indique une forte pression lithogénique dans ces milieux éloignés des sources directes, qui s’inclut dans le bruit de fond géochimique (e. g. Al, As, Co, Cr, Fe, Ni et Ti). Des sources additionnelles issues des activités anthropiques plus locales complètent régionalement les cortèges des éléments chimiques enregistrés (Cd, Cu, Sb ou Zn). La comparaison des échantillons de lichens et de mousses avec des spécimens historiques d’herbiers nous permet de retrouver ce contexte régional durant les siècles passés, et notamment de conforter les signatures lithologiques à travers le temps grâce aux terres rares. Ainsi, l’utilisation du charbon fossile apparaît être la source de contamination métallique dominante durant la fin du XIX e siècle et le début du XX e siècle, et plus récemment, une source additionnelle comme le transport routier (cas de Pb) a pu être notée. En parallèle, des facteurs influençant la bioaccumulation des métaux ont été testés : l’espèce considérée joue sur la capture des particules atmosphériques à travers la morphologie du thalle, et l’écorce support ne présente que peu d’influence. En considérant les signatures des dépôts atmosphériques, la végétation au travers des pluviolessivats apparaît influencer davantage les mousses terricoles que les lichens corticoles, ces derniers étant plus représentatifs des dépôts totaux. Des expérimentations de sorption/désorption montrent un processus rapide d’accumulation (une semaine) pour Pb et Cd, mais ne montrent ni compétition entre les métaux bioaccumulés, ni influence du lessivage sur la bioaccumulation. De nouvelles données concernant la sensibilité des espèces lichéniques face aux polluants métalliques ont pu être obtenues à partir de relevés de bioindication couplés à des analyses statistiques multivariées. / The atmospheric contamination by metals/metalloids (As, Cd, Cu, Pb, Sb, Zn…) and by nitrogen compounds impact the ecosystems. The atmospheric deposition is responsible of these harmful effects and its evaluation is complex and missing, particularly in remote environments like forest areas. The monitoring of trace element and nitrogen deposition at the national scale is carried out through two different approaches of biomonitoring by lichens and mosses: bioaccumulation and bioindication. The metal bioaccumulation points out a strong lithogenic pressure in these remote areas that is included in the geochemical background (e. g. Al, As, Co, Cr, Fe, Ni and Ti). Additional sources from more local anthropogenic activities are responsible for the regional context by the accumulation of other chemical elements (Cd, Cu, Sb or Zn). The comparison of current samples with herbarium specimens allows us getting back to historical regional influence one and half century ago, including consolidating the lithological influence over the time by rare earth elements. The use of fossil coal appears as a dominant source of metallic contamination in the late 19th century and the beginning 20th century. In parallel, the factors influencing the bioaccumulation of metals were evaluated: the entrapment of atmospheric particles is influenced by the morphology of the thallus but not by the bark. Considering the atmospheric deposition signature, vegetation via throughfall was found to be more influent for terricolous mosses than for corticolous lichens. Additional experiments of sorption/desorption showed a quick accumulation process (one week) for Pb and Cd, but neither metal competition, nor leaching influence on bioaccumulation were highlighted. New data on lichen species sensitivity to metal pollutants have been compiled through multivariate statistical analysis
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