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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Omgivningspåverkan vid sänkhammarborrning / Environment impact when drilling with DTH

Algmark, Carl, Eskilsson, Mattias January 2014 (has links)
Sänkhammarborrning är en metod som används för att utföra grundläggning med stålpålar. Metoden blir allt vanligare i Svenska tätbebyggda miljöer där krav ställs på låg omgivningspåverkan. Vid sänkhammarborrning borras ett foderrör av stål ner genom jordlagren till avsett djup, oftast till bärkraftigt berg. Foderröret lämnas sedan kvar, armeras, gjuts och utgör sedan själva pålen. Borrmaskinen består bland annat av en hammare som arbetar nere i hålet och drivs av antingen vatten eller luft. Borrföretagen har ofta tillgång till flera olika borrsystem men det saknas ibland underlag och forskning för hur olika borrsystem och metoder påverkar mark och omgivning vilket kan skapa en osäkerhet i projekteringsfasen och oförutsedda problem i utförandestadiet. Sänkhammarborrning anses ha en mindre massförträngande effekt men ger ändå en viss omgivningspåverkan både ovan och under mark. I den här studien har omgivningspåverkan under mark behandlats. Tre störningskällor har undersökts; vibrationer, uppspolning och trycksättning. Syftet har varit att teoretiskt undersöka hur vattendrivet- och luftdrivet sänkhammarborrsystem påverkar undergrunden i samband med att stålrörspålar installeras. För att nå syftet har en litteraturstudie och en intervjustudie genomförts. Även två fältbesök har gjorts. Litteratur och intervjuer har sedan analyserats med utgångspunkt i de tre nämnda fenomenen. Resultatet visar att de viktigaste faktorerna som påverkar hur stor omgivningspåverkan blir är markförutsättningar, maskinutrustning och utförandet. Vattendriven borrning visar sig löpa mindre risk att påverka omgivningen när det gäller uppspolning och trycksättning men om borrningen utförs på rätt sätt kan omgivningspåverkan undvikas även vid luftdriven borrning. De två borrsystemen har olika slagenergier och slagfrekvenser dock kan inga slutsatser dras av hur detta påverkar vibrationsnivåerna. Ett antal åtgärder finns för att minimera omgivningspåverkan, det handlar framförallt om att välja rätt borrsystem samt att borrningen utförs på rätt sätt.
2

Efeito da melatonina no desenvolvimento da resposta imune mediada por linfócitos T CD4. / Effect of melatonin on the development of CD4 T lymphocytemediated immune response.

Zenteno, Maria Emilia 12 November 2015 (has links)
Linfócitos T CD4+ (LTCD4) sofrem morte pelo reestímulo do TCR em um processo chamado de AICD (activation-induced cell death) no fim de uma resposta imune. Resultados prévios de nosso grupo de pesquisa mostraram que melatonina foi capaz de inibir o processo de AICD em LTCD4 em experimentos in vitro. Portanto, o objetivo deste trabalho é verificar se a melatonina é capaz de agir como estimulador, aumentando a resposta imune mediada pelos LTCD4 in vivo. Nós observamos que 3 e 9mg/Kg de melatonina aumentaram a resposta de DTH (Delayed-type Hypersensitivity), de forma diretamente proporcional à dose utilizada. O tratamento com melatonina estimulou um aumento da proliferação e do numero absoluto de LTCD4 específicos de antígeno. Em experimentos de diferenciação linfocitária in vitro, nós observamos que o tratamento com melatonina estimulou a produção de LTCD4 do perfil Th1 e Th2, no entanto inibiu a produção de linfócitos Th17. Em conclusão, nossos resultados sugerem um efeito estimulador da melatonina sobre a função de linfócitos T CD4+. / CD4+ T lymphocytes (LTCD4+) suffer cell death by a process known as activation-induced cell death (AICD) at the end of immune response. Previous results from our group showed that melatonin can inhibits AICD process in LTCD4 at in vitro experiments. Therefore, the aim of this work is verify if a melatonin can act as immune stimulator increasing a LTCD4-mediated immune response in vivo. We showed that 3 and 9 mg/Kg of exogenous melatonin added during immunization resulted in potentiation dose-dependent of Delayed-type hypersensitivity (DTH) response. The treatment with melatonin increased the absolute number LTCD4 antigen-specific, probably by increment of its proliferation. In experiment of T cell differentiation, we observed that the treatment with melatonin stimulated LTCD4 production of Th1 and Th2 profile however blocked the Th17 lymphocytes production. In conclusion, our results support the idea about a regulator role of melatonin on LTCD4 lymphocytes function for development of an immune response.
3

Efeito da melatonina no desenvolvimento da resposta imune mediada por linfócitos T CD4. / Effect of melatonin on the development of CD4 T lymphocytemediated immune response.

Maria Emilia Zenteno 12 November 2015 (has links)
Linfócitos T CD4+ (LTCD4) sofrem morte pelo reestímulo do TCR em um processo chamado de AICD (activation-induced cell death) no fim de uma resposta imune. Resultados prévios de nosso grupo de pesquisa mostraram que melatonina foi capaz de inibir o processo de AICD em LTCD4 em experimentos in vitro. Portanto, o objetivo deste trabalho é verificar se a melatonina é capaz de agir como estimulador, aumentando a resposta imune mediada pelos LTCD4 in vivo. Nós observamos que 3 e 9mg/Kg de melatonina aumentaram a resposta de DTH (Delayed-type Hypersensitivity), de forma diretamente proporcional à dose utilizada. O tratamento com melatonina estimulou um aumento da proliferação e do numero absoluto de LTCD4 específicos de antígeno. Em experimentos de diferenciação linfocitária in vitro, nós observamos que o tratamento com melatonina estimulou a produção de LTCD4 do perfil Th1 e Th2, no entanto inibiu a produção de linfócitos Th17. Em conclusão, nossos resultados sugerem um efeito estimulador da melatonina sobre a função de linfócitos T CD4+. / CD4+ T lymphocytes (LTCD4+) suffer cell death by a process known as activation-induced cell death (AICD) at the end of immune response. Previous results from our group showed that melatonin can inhibits AICD process in LTCD4 at in vitro experiments. Therefore, the aim of this work is verify if a melatonin can act as immune stimulator increasing a LTCD4-mediated immune response in vivo. We showed that 3 and 9 mg/Kg of exogenous melatonin added during immunization resulted in potentiation dose-dependent of Delayed-type hypersensitivity (DTH) response. The treatment with melatonin increased the absolute number LTCD4 antigen-specific, probably by increment of its proliferation. In experiment of T cell differentiation, we observed that the treatment with melatonin stimulated LTCD4 production of Th1 and Th2 profile however blocked the Th17 lymphocytes production. In conclusion, our results support the idea about a regulator role of melatonin on LTCD4 lymphocytes function for development of an immune response.
4

Diseño e implementación de un Sistema UP LINK DTH

Amorós Tirado, Jorge Félix Iván January 2013 (has links)
Hasta el 2012, con la digitalización de las señales de televisión por satélite, por cable y últimamente también de la televisión terrestre, se vienen presentando en el país requerimientos técnicos similares a los de países denominados desarrollados, con un dinamismo cada vez mayor que ha obligado la creación de empresas locales altamente especializadas en la implementación de Up Links para DTH, transmisiones deportivas con tecnología digital de última generación, inserción de nuevos canales en las grandes cabeceras CATV, la centralización de canales en las mismas, etc. El día a día de éste tipo de empresas es la configuración en planta y la instalación de complejos sistemas que incluyen encoders, multiplexers, amplificadores, decoders, módems, routers, antenas parabólicas con diámetros que van desde 1.2m hasta 9m. Los cálculos de enlace (link budget) son realizados ahora localmente sin depender ya de los cálculos de los operadores satelitales, para lo cual se emplean programas de computador avanzados y precisos.
5

Die Rolle von IFN Gamma in der Immunregulation

Eulenburg, Katharina zu 14 March 2007 (has links)
In der vorliegenden Arbeit wurde die Rolle des Zytokins IFN-gamma in einer Th1-vermittelten Entzündungsreaktion untersucht. Ausgangspunkt war die Beobachtung, dass die Blockade des als proinflammatorisch beschriebenen Zytokins IFN-gamma zu einer chronischen Entzündung führte. Ziel war also das Erkennen und Verstehen der Regulationsmechanismen, sowie die Identifizierung beteiligter Zelltypen und beteiligter Moleküle. Mit Hilfe von Knochenmarkschimären konnte gezeigt werden, dass die Zelle, die von Th1-Zellen sekrektiertes IFN-gamma erkannte, haematopoietischen Ursprungs war. Zum weiteren Verständnis der Regulationsmechanismen wurden Tiere unter IFN-gamma-Blockade mit Tieren, die einen Kontrollantikörper erhielten, verglichen. Mittels Immunhistochemie konnte in Kontrolltieren eine starke Expression von iNOS am Ort der Entzündung nachgewiesen werden, während in Tieren, in denen IFN-gamma blockiert wurde, keine iNOS Expression nachzuweisen war. Mit Hilfe von iNOS-defizienten Mäusen konnte gezeigt werden, dass NO tatsächlich funktionell essentiell in der IFN-gamma abhängigen Selbstlimitation der Th1-vermittelten Entzündungsreaktion war. Weitere Charakterisierung der iNOS-exprimierenden Zellen mittels FACS-Analyse ergab, dass iNOS-produzierende Zellen den Oberflächenmarker CD11b exprimierten. Diese iNOS-produzierenden Zellen waren fast ausschließlich am Ort der Entzündung zu finden. Die funktionelle in vitro Charakterisierung dieser Zellen nach ex vivo Isolierung ergab, dass diese Zellen die Proliferation von CD4+ T-Zellen supprimierten und deshalb als Myeloide-Suppressor-Zellen bezeichnet werden können. Der hier untersuchte IFN-gamma vermittelte Regulationsmechanismus scheint auf andere T-Zell-Systeme übertragbar zu sein, da IFN-gamma Blockade in einer durch CD8+ Effektor-T-Zellen vermittelten Entzündung auch zu einer Verlängerung der Entzündung führte. Zusammenfassend konnte gezeigt werden, dass das Zytokin IFN-gamma während der Effektorphase einer Immunreaktion wichtig für die Selbstlimitation ist. / The aim of the work was to understand the role of the cytokine IFN-gamma in a Th1 dependent inflammation. Starting point was the observation that the blockade of IFN-gamma, which is generally regarded as a proinflammatory cytokine, led to a more severe inflammation. We were therefore aiming at a better understanding of the mechanism of regulation, the identification of important cell types and downstream effector molecules. With the help of bone marrow chimeras we could show that the host cell which recognises IFN-gamma is of haematopoietic origin. For further understanding we compared animals under IFN-gamma neutralisation with control animals. Immunohistochemical staining revealed a strong expression of the enzyme iNOS in control animals whereas iNOS was merely detectable under IFN-gamma neutralisation. With the help of iNOS deficient animals we could show, that NO is indeed essential as downstream effector molecule. Further characterisation via FACS analysis showed that iNOS production was only observed among CD11b+ cells, roughly half of the iNOS expressing cells were also positive for GR-1. iNOS expression could only be detected at the site of inflammation. Functional in vitro characterisation of these cells after ex vivo isolation revealed that they suppressed the proliferation of CD4+ T cells. They can therefore be regarded as myeloid suppressor cells. To study whether the observed mechanisms of regulation are of any general importance, we looked at a DTH response mediated by CD8+ effector T cells and indeed we could observe a more severe inflammation under IFN-gamma neutralisation, although the effect was not quite as strong as in the Th1 mediated inflammation. In summary we could show, that the cytokine IFN-gamma is important in the limitation of the effector phase of an ongoing immune response.
6

Aspectos ambientais e sociais envolvidos na transmiss?o da L. chagasi no munic?pio de Parnamirim/RN

Lima, Iraci Duarte de 07 August 2009 (has links)
Made available in DSpace on 2014-12-17T14:13:44Z (GMT). No. of bitstreams: 1 IraciDL_Dissert.pdf: 1259983 bytes, checksum: 9fb9c026a74636e1c8e0d88ea967084d (MD5) Previous issue date: 2009-08-07 / Visceral leishmaniasis h?s adapted in the past 20 years to periurban and urban areas, and in Natal, Rio Grande do Norte, it became endemic. Thid study aimed to evaluate the environmental and social aspectsof Leishmania chagasi infection and its epidemiologic transmission chain in an urban, periurban and rural area of Parnamirim-RN. A study with three sections was conducted: Section 1: Sectional study of the human and canine infection by L. chagasi and its environmental and social determinants. Section 2: Observational longitudinal cohort to evaluate the dynamics of the canine infection. Section 3: Longitudinal study to evaluate the behavior of Lu. Longipalpis vector and the seasonal factors related to its dynamics. To include in the study the hauses were randomly selected and georreferenciated. Montenegro skin test was done in the human population and blood samples were collected for anti-Leishmania antibody detection. The canine population was examinated for L. chagasi infection by RIFI, ELISA and ELISA for rK39. An entomologic surveillance was monthly done with CDC light trapsin 10 houses of each locality. Quantitative and qualitative analyses was done using STATISC 6.0. Probality and prediction maps were done using ArcGis 9.0 model. In the human population L. chagasi infection was associated with the area of the hause, age, sex, population densyti, vegetation, kind of the floor of thr hause, water and resides destiny. In the canine population L. chagasi infection was associated with the breed, size, time of living in the hause, presence of dogs in the neighborhood, presence of horses and donkeys in the neighborhood, vegetation, kind of the floor and walls of the hause. The human infection was associated with canine infction only when analyzed taking into account the locality. In the prospective study, serum conversion and antibody lost observed in 30,8% and 22% of the animals examined, respectively. The human infection rate by L. chagasi was 24,6%, by the presence of anti-Leishmania antibody and 38,6% by the Montenegro skin test. The canine infection rate 32,5% by the presence of anti-Leishmania antibody. The vector Lu longipalpis showed an atypical behavior. These results indicate that environmental and social factors are important variables associated with L. chagasi infection in humans and canines, with punctual association of thr last two. Control measures of the infection on the studied points are necessary, in the aim to reduce the endemic focus of the disease in the study area. This research was carried out in a multidisciplinary involving the categories of: doctor, biologist, veterinarian, statistical, pharmaceutical and biochemical / A leishmaniose visceral ? uma doen?a que nos ?ltimos 20 anos adaptou-se ?s ?reas periurbanas e urbanas, tornando-se end?mica na regi?o metropolitana de Natal, Rio Grande do Norte. Este estudo teve como objetivo avaliar os aspectos ambientais, sociais e a cadeia epidemiol?gica de transmiss?o por Leishmania chagasi em ?rea urbana, periurbana e rural do Munic?pio de Parnamirim-RN. Realizou-se um estudo com tr?s subestudos: Subestudo 1: Estudo Transversal da infec??o humana e seus determinantes socioambientais no ano de 2005. Subestudo 2: Estudo observacional longitudinal com coorte fixa para avaliar a din?mica da infec??o canina por L. chagasi no per?odo de 2005/2006. Subestudo 3: Estudo longitudinal para avaliar a fauna de flebotom?neos e a densidade de L. longipalpis associando aos fatores clim?ticos. Para inclus?o no estudo, os im?veis foram selecionados aleatoriamente e georreferenciados. Na popula??o humana desses im?veis, foi realizado teste de Montenegro e coleta de sangue para detec??o de anticorpos antileishmania. A popula??o canina foi examinada quanto ? infec??o por L. chagasi pelo m?todo de RIFI, ELISA EB e ELISA para rK39. Foi realizado monitoramento entomol?gico mensal com armadilhas CDC em 10 im?veis de cada localidade. Foi realizado an?lise quantitativa e qualitativa atrav?s do STATISC 6.0 e constru??o de mapas de predi??o e probabilidade atrav?s do modelo do ArcGis 9.0. Foi encontrada associa??o da infec??o humana por L. chagasi com a ?rea de resid?ncia, idade, sexo, densidade populacional, vegeta??o, tipo de piso do im?vel e destino de ?gua e dejetos. Na popula??o canina, foi observada associa??o da infec??o por L. chagasi quanto ? ra?a, ao porte, sintomas, tempo de moradia no im?vel, presen?a de c?es na vizinhan?a, presen?a de cavalos e jumentos na vizinhan?a, tipo de vegeta??o da ?rea. A infec??o humana estava relacionada com a infec??o canina apenas quando analisada considerando-se a localidade. No estudo prospectivo, foi observada soroconvers?o e perda de anticorpos em 30,8% e 22% dos animais examinados, respectivamente. A taxa de infec??o humana por Leishmania chagasi foi de 24,6%, quando avaliada pela presen?a de anticorpos antileishmania e de 38,6% quando avaliada pelo teste de Montenegro. A taxa de infec??o canina foi 32,5% quando avaliada pela presen?a de anticorpos antileishmania. O vetor Lu. longipalpis apresentou um comportamento at?pico. Os resultados indicam que fatores ambientais e sociais s?o importantes vari?veis associadas ? infec??o por L. chagasi em humanos e caninos, sendo as ?ltimas pontualmente associadas. Desta forma, s?o necess?rias medidas de controle da infec??o que enfoquem os pontos estudados, visando a n?o manuten??o da endemicidade na ?rea estudada. Esta pesquisa foi realizada de forma multidisciplinar envolvendo as categorias de: m?dico, bi?logo, veterin?rio, estat?stico, nutricionista e farmac?utico bioqu?mico
7

Avaliação comparativa das proteinas de fusão cmx e ecmx no teste de mantoux para o diagnóstico de tuberculose / Comparative evaluation of fusion proteins cmx and ecmx by mantoux technique for tuberculosis diagnosis

Sánchez, Tatiana Marlene Galvez 20 February 2017 (has links)
Submitted by Cássia Santos (cassia.bcufg@gmail.com) on 2017-03-24T11:22:47Z No. of bitstreams: 2 Dissertação - Tatiana Marlene Galvez Sánchez - 2017.pdf: 3124839 bytes, checksum: 942aa6d4fa9aa30babb4eb0d7e04a805 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2017-03-24T12:39:25Z (GMT) No. of bitstreams: 2 Dissertação - Tatiana Marlene Galvez Sánchez - 2017.pdf: 3124839 bytes, checksum: 942aa6d4fa9aa30babb4eb0d7e04a805 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-03-24T12:39:25Z (GMT). No. of bitstreams: 2 Dissertação - Tatiana Marlene Galvez Sánchez - 2017.pdf: 3124839 bytes, checksum: 942aa6d4fa9aa30babb4eb0d7e04a805 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-02-20 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Outro / Tuberculin skin test (TST) identifies a previous exposed to M. tuberculosis (Mtb) using an intradermal inoculation of purified protein derivates (PPD) that result in a delayed hypersensitivity reaction (DTH). Interferon-gamma release assay (IGRA) was suggested to replace TST. The IGRA uses antigens, ESAT-6 and CFP-10, absent in all BCG strains and some non tuberculous mycobacteria (NTM). However, reproducibility and high cost were limitations for endemic countries. For this reason, the development of new diagnose test for latent TB is necessary. Fusion proteins developed by our group has been recognized by the immune response generated by the infection with Mycobacterium tuberculosis. Thus the aim of this work was to evaluate the capacity of CMX or ECMX to be used in a Skin test for tuberculosis. BALB/c mice infected with Mtb were euthanized forty-five days after infection. Spleens, lungs and draining lymph nodes of infected mice were processed and evaluated by flow cytometry Both CD4 and CD8 IFN+ cells were able to recognize rCMX and rECMX. The skin test followed an evaluation of thickness/swelling ≥ PPD 2UT (positive control) to consider positive DTH. Based on thickness, at 24 h, rCMX 25μg (0.37±0.02) and rECMX 15-25μg (0.38±0.03/0,62±0,12) induced a positive DTH response. At 48h, rCMX 25μg (0.28±0.03) and rECMX 25μg (0.5±0.04) induced also a positive DTH reaction. In conclusion, fusion proteins rCMX and rECMX are recognized by infected mice with Mtb and skin test using rECMX 25μg induced better DTH response that of conventional PPD. / A prova tuberculínica (PT) é um teste cutâneo que identifica a exposição prévia ao M. tuberculosis (Mtb), mediante a inoculação via intradérmica do derivado protéico purificado (PPD) de Mtb, o que resulta em uma reação de hipersensibilidade do tipo tardia (DTH). O ensaio de liberação de IFN-γ (IGRA) foi indicado para substituir a PT. O IGRA usa os antígenos ausentes na BCG e algumas micobactérias não causadoras de TB (MNT), ESAT-6 e CFP-10. Porém, apresenta falta de reprodutibilidade e alto custo quando usado em populações endêmicas para TB. Diante disso, o desenvolvimento de novos testes de diagnóstico é necessário. Nosso grupo desenvolveu proteínas de fusão que são reconhecidas por linfócitos gerados pela infecção com Mtb. Assim, o trabalho propõe avaliar a utilização das proteínas rCMX e rECMX no desenvolvimento de um teste cutâneo de diagnóstico para tuberculose. Camundongos BALB/c foram infectados com Mtb H37Rv. Após 45 dias, a infecção induziu linfócitos T CD4+ e CD8+ produtores de IFN-γ específicos para rCMX e rECMX no baço, pulmões e linfonodos drenantes. Enquanto ao teste cutâneo realizado 45 dias após a infecção, a leitura de espessura/inchaço ≥ PPD 2UT (controle positivo) indicou uma reação de DTH positiva. Avaliando a espessura 24h após o inóculo, rCMX 25μg (0.37±0.02) e rECMX 15-25μg (0.38±0.03/0,62±0,12) induziram reação de DTH positiva. As 48h, rCMX 25μg (0.28±0.03) e rECMX 25μg (0.5±0.04) também apresentaram reação positiva. Enquanto o inchaço as 24h, só a rECMX apresentou DTH positiva. Em conclusão, este trabalho mostra que as proteínas rCMX e rECMX são reconhecidas pela resposta celular de camundongos infectados com Mtb, e quando usadas no teste cutâneo induziram reação de DTH positiva comparável e até superior ao PPD convencional. Dessa forma, é recomendada a avaliação das proteínas de fusão em outros modelos animais e posteriormente em humanos.
8

Effects of <i>in ovo</i> herbicide exposure in newly hatched domestic chickens (<i>Gallus gallus</i>) and ducks (<i>Anas platyrhynchos</i>)

Stoddart, Reagen A 04 January 2007
Agriculture is a valuable economic resource in western Canada, but for decades farmers have focused on intensive production practices while ignoring the long-term health and maintenance of the land. In recent years, the use of conservation agricultural techniques has been encouraged in an effort to conserve prairie landscape while sustaining cropland productivity. Sustainable agricultural practices that promote soil and water conservation and benefit wildlife and prairie biodiversity include conservation tillage and planting of winter cereal crops. Many species of wild birds nest in the ground cover provided by minimum tillage and fall seeded cropland in the spring. Although habitat quality in conservation areas is superior for birds, there is potential for eggs of ground nesting birds to be exposed to herbicides during spring weed control operations. Herbicides commonly used on the prairies to control weed growth in conservational systems include 2,4-D and Buctril-M®. Since the subtlethal effects of exposure to these herbicides may include DNA damage and immunomodulation, the overall goal of this study was to assess whether <i>in ovo</i> exposure to the herbicides 2,4-D and Buctril-M® adversely affects genetic material and/or immune system function in newly hatched domestic chickens (<i>Gallus gallus</i>) and ducks (<i>Anas platyrhynchos</i>), as surrogates for wild bird species.<p>Study design attempted to reproduce actual field exposures by use of an agricultural field spray simulator to apply formulated herbicides (as opposed to pure active ingredients) at recommended crop application rates. In three separate experiments, fertile chicken eggs were sprayed with 2,4-D ester formulation or with Buctril-M® formulation, and fertile duck eggs were sprayed with 2,4-D ester formulation, during either an early (embryonic day 6) or late (embryonic day 15 for chickens or embryonic day 21 for ducks) stage of incubation. Genotoxicity and immune system function were evaluated in the hatchlings as the main toxicological endpoints to assess potential subtle effects from herbicide exposure, but additional measures of general health and development were also evaluated. Two endpoints were used to assess subtle changes to genetic integrity. The comet assay was used to detect structural damage (strand breaks) in avian lymphocyte DNA, as an index of acute genotoxic effects. Flow cytometry was used to examine potential clastogenic effects of the herbicides, by determining if chromosomal changes resulted in variability in the DNA content of avian erythrocytes. Several endpoints were examined to evaluate potential exposure-induced effects on the immune system. Immunopathological assessment of chicks and ducklings included differential lymphocyte counts, as well as immune organ weights and histopathology. The cell-mediated and humoral immune responses in hatchlings were assessed using the delayed-type hypersensitivity test and measurement of systemic antibody production in response to immunization, respectively. Exposure of fertile chicken and duck eggs to Buctril-M® or 2,4-D had no effects on the biomarkers of genetic integrity in this study. Differences in herbicide treatment (high and low concentrations) and times of exposure (early and late incubation stages) did not translate into noticeable factor effects in final model analyses for any of the genotoxicity assay variables evaluated in newly hatched chickens exposed in ovo to 2,4-D. Similarly, comet assay outcomes in chicks exposed to Buctril-M® were not significantly associated with either herbicide treatment or time of exposure as fixed effect factors. Results of the comet assay using peripheral lymphocytes from ducklings provided evidence of potential primary genetic damage associated with the time of spray exposure in ovo. Comet tail DNA content was significantly associated (P = 0.0269) with exposure times, suggesting that ducks may be increasingly sensitive to spray exposure conditions at an early stage of embryological development. Effects of exposure timing were not attributable to herbicide treatment. Although 2,4-D exposure time was associated with DNA strand breakage in ducklings, there was no evidence of chromosomal damage. However, an association between the HPCV values (a measure of DNA content variability) and time of spray exposure was observed in the experiment where 21-day-old chickens were treated in ovo with Buctril-M®. The mean HPCV value for the early exposure group (E6) was significantly greater (P = 0.0210) than that of the group treated later in incubation (E15). However, Buctril-M® the concentration of herbicide did not have any influence on this outcome, and the reason for the difference between exposure times is uncertain, but may be attributed to stress associated with manipulations during spraying. An increase in HPCV, reflecting greater intercellular DNA variability, is indicative of increased incidence of chromosomal damage, which may be an effect of disturbance during early periods of incubation as a result of exposure conditions.<p>Among the panel of immunotoxicity tests conducted to evaluate the effects of <i>in ovo</i> exposure to 2,4-D and Buctril-M® on the developing avian immune system, only heterophil/ lymphocyte (H/L) ratios and relative immune organ weights were significantly associated with either herbicide treatment or time of spray exposure in all three experiments. In 21-day-old chicks exposed in ovo to 2,4-D, relative bursa weight was associated with the different herbicide treatments (P = 0.0006). Relative bursa weights were significantly lower in chicks in the low dose group, while the opposite effect was observed in the high dose chicks, compared with the controls. It is unlikely that the observed decrease in bursa weight in the low dose group is causally related to herbicide exposure because a consistent dose-response effect was not observed, but this outcome may be explained by a compensatory immune response. The relative spleen weights of newly hatched chickens exposed in ovo to Buctril-M® exhibited a significant association with herbicide treatment (P = 0.0137). Relative spleen weights for birds in the low dose treatment groups were significantly different than both the control (P = 0.0179) and high dose groups (P = 0.0125). However, there was no significant difference between high dose and control groups, and this outcome reduces the likelihood of a causal relationship between spleen weight and herbicide exposure. In the parallel experiment involving in ovo exposure to 2,4-D to ducklings, relative bursa weight was associated with time of spray exposure (P = 0.0434). Ducklings that hatched from eggs exposed to spray on day 6 of incubation exhibited greater mean relative bursa weights than the birds exposed to spray at a later incubation stage (E21). This result implies that spray exposure during earlier stages of development may result in conditions which affect the humoral immune response, if increased bursal weight is associated with increased B lymphocyte and antibody production. In the same experiment, mean H/L ratios in peripheral blood samples from 21-day-old ducklings were significantly different between the groups treated with the high concentration of 2,4-D and water (control) (P = 0.0395). Although ratios from the birds in the low dose groups were not significantly different from the control groups, changes in H/L ratio values demonstrate a dose dependent relationship with increasing herbicide exposure.<p>Residue analysis of chicken and duck eggs in this study measured transfer of herbicide through the shell and into the embryo 24 hours and up to 5 days (chickens only) after spraying. Mean 2,4-D residue concentrations were higher in both chicken and duck eggs from the high dose (10X) groups than in eggs exposed to the recommended field rate of herbicide application (1X). Embryo residue concentrations in the chicken eggs increased from the day following exposure to 5 days after spraying, in both low and high dose groups. This observation indicates that the risk of contaminant-induced adverse effects may continue to increase for at least several days after exposure, thereby influencing the concentration of herbicide to which the developing embryo is exposed.<p>On the Canadian prairies, wild bird eggs are potentially to be exposed to 2,4-D and Buctril-M® during various stages of embryonic development. The present study examined effects of herbicide exposure at two distinct times during incubation, and demonstrated the potential for subtle impacts on genetic integrity and the immune system. Results indicate that spray exposure during earlier stages of organogenesis may cause more significant adverse effects. Given the possible harmful consequences of the observed changes on the long-term health of wild birds, further research is needed in order to better characterize the risks of in ovo agrochemical exposure in prairie ecosystems.
9

Effects of <i>in ovo</i> herbicide exposure in newly hatched domestic chickens (<i>Gallus gallus</i>) and ducks (<i>Anas platyrhynchos</i>)

Stoddart, Reagen A 04 January 2007 (has links)
Agriculture is a valuable economic resource in western Canada, but for decades farmers have focused on intensive production practices while ignoring the long-term health and maintenance of the land. In recent years, the use of conservation agricultural techniques has been encouraged in an effort to conserve prairie landscape while sustaining cropland productivity. Sustainable agricultural practices that promote soil and water conservation and benefit wildlife and prairie biodiversity include conservation tillage and planting of winter cereal crops. Many species of wild birds nest in the ground cover provided by minimum tillage and fall seeded cropland in the spring. Although habitat quality in conservation areas is superior for birds, there is potential for eggs of ground nesting birds to be exposed to herbicides during spring weed control operations. Herbicides commonly used on the prairies to control weed growth in conservational systems include 2,4-D and Buctril-M®. Since the subtlethal effects of exposure to these herbicides may include DNA damage and immunomodulation, the overall goal of this study was to assess whether <i>in ovo</i> exposure to the herbicides 2,4-D and Buctril-M® adversely affects genetic material and/or immune system function in newly hatched domestic chickens (<i>Gallus gallus</i>) and ducks (<i>Anas platyrhynchos</i>), as surrogates for wild bird species.<p>Study design attempted to reproduce actual field exposures by use of an agricultural field spray simulator to apply formulated herbicides (as opposed to pure active ingredients) at recommended crop application rates. In three separate experiments, fertile chicken eggs were sprayed with 2,4-D ester formulation or with Buctril-M® formulation, and fertile duck eggs were sprayed with 2,4-D ester formulation, during either an early (embryonic day 6) or late (embryonic day 15 for chickens or embryonic day 21 for ducks) stage of incubation. Genotoxicity and immune system function were evaluated in the hatchlings as the main toxicological endpoints to assess potential subtle effects from herbicide exposure, but additional measures of general health and development were also evaluated. Two endpoints were used to assess subtle changes to genetic integrity. The comet assay was used to detect structural damage (strand breaks) in avian lymphocyte DNA, as an index of acute genotoxic effects. Flow cytometry was used to examine potential clastogenic effects of the herbicides, by determining if chromosomal changes resulted in variability in the DNA content of avian erythrocytes. Several endpoints were examined to evaluate potential exposure-induced effects on the immune system. Immunopathological assessment of chicks and ducklings included differential lymphocyte counts, as well as immune organ weights and histopathology. The cell-mediated and humoral immune responses in hatchlings were assessed using the delayed-type hypersensitivity test and measurement of systemic antibody production in response to immunization, respectively. Exposure of fertile chicken and duck eggs to Buctril-M® or 2,4-D had no effects on the biomarkers of genetic integrity in this study. Differences in herbicide treatment (high and low concentrations) and times of exposure (early and late incubation stages) did not translate into noticeable factor effects in final model analyses for any of the genotoxicity assay variables evaluated in newly hatched chickens exposed in ovo to 2,4-D. Similarly, comet assay outcomes in chicks exposed to Buctril-M® were not significantly associated with either herbicide treatment or time of exposure as fixed effect factors. Results of the comet assay using peripheral lymphocytes from ducklings provided evidence of potential primary genetic damage associated with the time of spray exposure in ovo. Comet tail DNA content was significantly associated (P = 0.0269) with exposure times, suggesting that ducks may be increasingly sensitive to spray exposure conditions at an early stage of embryological development. Effects of exposure timing were not attributable to herbicide treatment. Although 2,4-D exposure time was associated with DNA strand breakage in ducklings, there was no evidence of chromosomal damage. However, an association between the HPCV values (a measure of DNA content variability) and time of spray exposure was observed in the experiment where 21-day-old chickens were treated in ovo with Buctril-M®. The mean HPCV value for the early exposure group (E6) was significantly greater (P = 0.0210) than that of the group treated later in incubation (E15). However, Buctril-M® the concentration of herbicide did not have any influence on this outcome, and the reason for the difference between exposure times is uncertain, but may be attributed to stress associated with manipulations during spraying. An increase in HPCV, reflecting greater intercellular DNA variability, is indicative of increased incidence of chromosomal damage, which may be an effect of disturbance during early periods of incubation as a result of exposure conditions.<p>Among the panel of immunotoxicity tests conducted to evaluate the effects of <i>in ovo</i> exposure to 2,4-D and Buctril-M® on the developing avian immune system, only heterophil/ lymphocyte (H/L) ratios and relative immune organ weights were significantly associated with either herbicide treatment or time of spray exposure in all three experiments. In 21-day-old chicks exposed in ovo to 2,4-D, relative bursa weight was associated with the different herbicide treatments (P = 0.0006). Relative bursa weights were significantly lower in chicks in the low dose group, while the opposite effect was observed in the high dose chicks, compared with the controls. It is unlikely that the observed decrease in bursa weight in the low dose group is causally related to herbicide exposure because a consistent dose-response effect was not observed, but this outcome may be explained by a compensatory immune response. The relative spleen weights of newly hatched chickens exposed in ovo to Buctril-M® exhibited a significant association with herbicide treatment (P = 0.0137). Relative spleen weights for birds in the low dose treatment groups were significantly different than both the control (P = 0.0179) and high dose groups (P = 0.0125). However, there was no significant difference between high dose and control groups, and this outcome reduces the likelihood of a causal relationship between spleen weight and herbicide exposure. In the parallel experiment involving in ovo exposure to 2,4-D to ducklings, relative bursa weight was associated with time of spray exposure (P = 0.0434). Ducklings that hatched from eggs exposed to spray on day 6 of incubation exhibited greater mean relative bursa weights than the birds exposed to spray at a later incubation stage (E21). This result implies that spray exposure during earlier stages of development may result in conditions which affect the humoral immune response, if increased bursal weight is associated with increased B lymphocyte and antibody production. In the same experiment, mean H/L ratios in peripheral blood samples from 21-day-old ducklings were significantly different between the groups treated with the high concentration of 2,4-D and water (control) (P = 0.0395). Although ratios from the birds in the low dose groups were not significantly different from the control groups, changes in H/L ratio values demonstrate a dose dependent relationship with increasing herbicide exposure.<p>Residue analysis of chicken and duck eggs in this study measured transfer of herbicide through the shell and into the embryo 24 hours and up to 5 days (chickens only) after spraying. Mean 2,4-D residue concentrations were higher in both chicken and duck eggs from the high dose (10X) groups than in eggs exposed to the recommended field rate of herbicide application (1X). Embryo residue concentrations in the chicken eggs increased from the day following exposure to 5 days after spraying, in both low and high dose groups. This observation indicates that the risk of contaminant-induced adverse effects may continue to increase for at least several days after exposure, thereby influencing the concentration of herbicide to which the developing embryo is exposed.<p>On the Canadian prairies, wild bird eggs are potentially to be exposed to 2,4-D and Buctril-M® during various stages of embryonic development. The present study examined effects of herbicide exposure at two distinct times during incubation, and demonstrated the potential for subtle impacts on genetic integrity and the immune system. Results indicate that spray exposure during earlier stages of organogenesis may cause more significant adverse effects. Given the possible harmful consequences of the observed changes on the long-term health of wild birds, further research is needed in order to better characterize the risks of in ovo agrochemical exposure in prairie ecosystems.
10

Grundförstärkning med pålar i berg : I befintlig konstruktion med begränsat utrymme

Höglund, Madicken, Larsson, Marcus January 2020 (has links)
This study has been done in order to examine which type of pile, pile driving- and waterproofing methodsare most suited for an existing building. A building that will undergo an extensive reinforcement of itsfoundation.The study has been made in regard to the following conditions:● Different types of clay soil (Cohesion soil)● Underlying rock structure with heavy incline (8° slope)● Sensitive environment for vibrations and ground displacements● Limited accessibility (Room and maximum weight)● Compressive and tensile forces● Pool (Water environment)To answer the questions of statement a scientific literature study, interview with a foundation expert,calculations in sizing, but also time and cost analysis has been conducted. A site visit to an object ofreference, Nya Krav Himmerfjärdsverket, occurred where a reconstruction of an existing building withextensive work of reinforcement to its’ foundation was in progress.The steel pipe pile with anchor and steel core pile are the best pile types in such conditions as compressiveand tensile forces, clay soil with underlying inclined rock bed, limited accessibility and sensitivesurrounding environment. Which pile type, pile driving- and waterproofing methods that are most suited forsuch conditions is different for each project. The steel core pile is more suitable for higher loads, rockstructures in incline and when verification of load capacity is not needed. At the same time the steel pipepile is more suited when the underlying rock bed is far below ground level, where you would need manypile elements and joints. In addition, the steel pipe pile is suitable for buildings with a complex loaddistribution, where a greater number of piles with lower load capacities is needed in order to satisfy this.The best pile driving method for drilling in sensitive environment is the water equipped down-the-hole(DTH) drill. This drilling method is gentle to surrounding piles in existing building.In order to minimise the risk of water penetration and then expand the life span of the construction, use ofa combination of different waterproofing systems is to prefer when waterproofing pile heads or pilefoundations.

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