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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.
171

Modelo de análise de populações de plantas daninhas resistentes a herbicidas / Model analysis of weed populations resistant to herbicides

Kajino, Henrique Sadao 30 September 2011 (has links)
Este trabalho propõe um modelo dinâmico para análise de populações de plantas daninhas resistentes a herbicidas. O modelo representa a dinâmica populacional causada por um aumento na proporção de plantas resistentes a herbicidas, resultante da recombinação genética modificada pela pressão seletiva causada pelo herbicida. O aumento da resistência causa uma diminuição na eficácia da dose aplicada do herbicida sobre toda população e, eventualmente, compromete o controle desta população. São apresentados resultados de simulação da planta daninha Bidens subalternans, resistente ao herbicida nicosulfuron e tolerante ao herbicida atrazine, e da planta daninha Bidens pilosa, resistente ao herbicida chlorimuron-ethyl e tolerante ao herbicida imazetaphyr para diferentes doses de herbicidas. / This paper proposes a dynamic model for analysis of herbicide resistance in weed populations. The model represents population dynamic caused by an increase in the proportion of plants resistant to herbicides, resulting from genetic recombination modified by selective pressure caused by herbicide. The increase of resistance decreases the efficacy of the applied dose of herbicide over the entire population and, eventually compromises the population control. Results of simulation for different doses are presented for the weed Bidens subalternans, resistant to nicosulfuron and tolerant to atrazine, and for the weed Bidens pilosa, resistant to herbicide chlorimuron-ethyl and tolerant to imazetaphyr.
172

Anti-stressträning : En kvantitativ tvärsnittsstudie / Anti-stress exercise : A quantitative cross-sectional study

Lindberg, Felicia, Fex Rytterborg, Julia January 2019 (has links)
Syfte och frågeställningar: Syftet är att studera om träning på olika intensitetsnivåer påverkar upplevd stress hos kvinnor i Sverige. Denna studie kommer svara på dessa frågeställningar:  <ol type="1">Finns det någon skillnad i upplevd stress hos kvinnor som deltar på lågintensiv träning i form av promenader jämfört med kvinnor som deltar på högintensiv träning i form av löpning? Finns det någon skillnad i upplevd stress hos kvinnor som deltar på högintensiv träning i form av löpning jämfört med kvinnor som inte tränar alls? Finns det någon skillnad i upplevd stress hos kvinnor som deltar på lågintensiv träning i form av promenader jämfört med kvinnor som inte tränar alls?           Metod: Studien är en tvärsnittsstudie, genom enkätundersökningar har skillnader i upplevd stress jämförts på kvinnor med medelålder 39,03 år ( ± 14,44), som antingen tränat högintensivt eller lågintensivt. Resultaten har jämförts med en referensgrupp bestående av kvinnor som inte tränar alls. Perceived Stress Scale-10 (PSS10) inklusive tio stycken intensitets-frågor för inklusion i studien skickades ut via sociala medier, Facebook. Resultat: En signifikant skillnad sågs vid jämförandet av kvinnor som tränar högintensivt och referensgrupp, (p=0,001), poängmässig skillnad i PSS10; 7,67 poäng. Ingen signifikant skillnad redovisades mellan högintensiv och lågintensiv grupp (p=0,737), detsamma gällde lågintensiv och referensgrupp (p=0,081). Slutsats: Högintensiva kvinnor hade reducerad upplevd stress jämfört med kvinnor som inte tränade alls. Ingen skillnad i upplevd stress kunde urskiljas mellan kvinnor som tränar lågintensivt och kvinnor som tränade högintensivt. Samma gällde kvinnor som tränade på låg intensitet jämfört med kvinnor som inte tränade alls, ingen skillnad i upplevd stress. / Purpose and aims: The aim is to study if different exercise-intensities affects perceived stress in Swedish women. This study will answer the following questions: <ol type="1">Is there a difference in perceived stress in women who participate in low-intensity exercise in the form of walking compared to women who participate in high-intensity exercise in the form of running? Is there a difference in perceived stress in women who participate in high-intensity exercise in the form of running compared to women who do not exercise at all? Is there a difference in perceived stress in women who participate in low-intensity exercise in the form walking compared to women who do not exercise at all?           Method: The study is a cross-sectional study, through questionnaires, differences in perceived stress have been compared in women with a mean age of 39,03 years (± 14,44), who either exercised with high intensity or with low intensity. The results have been compared to a reference group consisting of non-training women. Perceived Stress Scale-10 (PSS10) together with ten intensity-questions for inclusion in the study was sent out via social media, Facebook. Results: A significant difference was detected in the comparison of the high intensity group and the reference group, (p=0.001), score difference in PSS10; 7,67 points. No significant difference between the high-intensity group and the low-intensity group (p=0.737), the same applied to the low-intensity group and the reference group (p=0,081). Conclusions: Women who participated in high intensity exercise had reduced percieved stress compared to women who did not exercise at all. No difference in percieved stress was observed between women who participated in low intensity exercise and women who participated in high intensity exercise. Similarly, no difference in percieved stress in women who participated in low intensity exercise and women who did not exercise at all.
173

Teratogenic Potential of Atrazine and 2,4-D Using Fetax

Morgan, M. K., Scheuerman, Phillip R., Bishop, C. S., Pyles, Rebecca A. 07 June 1996 (has links)
The teratogenic potential of commercial formulations of atrazine (40.8%) and 2,4-D was evaluated using FETAX (frog embryo teratogenic assay--Xenopus). Because these herbicides have been detected in ground and surface water, this study was designed to determine the adverse effects in buffer and natural water for both herbicides. All treatments showed a significant concentration-response effect on exposed embryos, except for the 2,4-D natural water sample. Atrazine (solubility of the commercial formula used 70 mg/L at 20 degrees C), compared to 2,4-D (solubility = 311 mg/L at pH = 1 and 25 degrees C), had a significantly greater teratogenic effect in both the buffer (atrazine EC50 = 33 mg/L, LC50 = 100 mg/L, TI = 3.03; 2,4-D EC50 = 245 mg/L, LC50 = 254 mg/L, TI = 1.04) and natural water samples (atrazine EC50 < 8 mg/L, LC50 = 126 mg/L; 2,4-D EC50 and LC50 > 270 mg/L). The 2,4-D EC50 and LC50 values for the buffer were similar at 245 mg/L and 254 mg/L. These similar values and the teratogenic index (TI) of 1.04 suggested that 2,4-D was more embryotoxic than teratogenic to frog embryos at high concentrations. Atrazine in natural water demonstrated a significantly greater EC50 (100% abnormality at 8 mg/L, the lowest test concentration) to frog embryos than the buffer experiment (EC50 = 33 mg/L). The extrapolated lowest observable adverse effect concentration (LOAEC) for the natural water experiment was 1.1 mg/L. These results suggest that atrazine toxicity is enhanced by the synergistic or additive effects of some component of the water or atrazine was already present in the sample. In contrast to atrazine, 2,4-D was less toxic in natural water than buffer. These results suggest that both atrazine and 2,4-D pose little threat, since their embryotoxicity and teratogenicity to frog embryos occur at high concentrations approaching their maximum solubility levels in water.
174

臨床實驗藥量特性之研究 / Characterizing dose response curve in clincal trials

方廷企 Unknown Date (has links)
在製藥工業中,藥量特性之研究常被應用於藥理學、毒物學及臨床試驗中。藥量特性之研究同時在臨床試驗中的第一階段的藥物安全性及第二階段的藥物有效性中扮演著重要的角色。透過藥量特性的研究,使我們對於藥物的開發有著更深一層的認識,並可藉此縮短藥物核准上市的時間。 在多數的情況下,我們對於藥物動力學之參數與藥物劑量間的線性關係,有著特別的興趣。基於這個目的,一些典型的方法即是由一般線性模式發展而成的。然而,這些典型的統計方法常遇到下列的難題而違反其假設:(一)不同藥物劑量間的異質變異性。(二)不滿足常態性的假設。針對這些問題,我們藉由比較不同劑量間的斜率關係的無母數檢定程序來評估其線性關係並刻劃出藥物的反應曲線,文中並藉此方法舉出交叉實驗之實例。 / The problem of characterizing dose response curve for a pharmacokinetic parameter over a specific dose range is considered. In many cases, it is of interest to determine dose linearity (or dose proportionality) between the pharmacokinetic parameters and dose levels. For this purpose, several classical methods based on a general linear model procedure are available. However, two difficulties commonly encountered, namely (i) heterogeneity of the varibility at different dose levels and (ii) violation of the normality assumptions, often make the classical methods not applicable. To account for these problems, we propose a general nonparametric test procedure by comparing the slopes at different dose level to asses dose linearity and to characterize dose response curve. An example concerning the study of dose response of a compound based on a four-way crossover experiment is presented.
175

Quantification of Radiation Induced DNA Damage Response in Normal Skin Exposed in Clinical Settings

Simonsson, Martin January 2011 (has links)
The structure, function and accessibility of epidermal skin provide aunique opportunity to study the DNA damage response (DDR) of a normaltissue. The in vivo response can be examined in detail, at a molecularlevel, and further associated to the structural changes, observed at atissue level. We collected an extensive skin biopsy material frompatients undergoing fractionated radiotherapy for 5 to 7 weeks. Several end-points inthe DDR pathways were examined before, during and after the treatment. Quantification of DNA double strand break (DSB) signalling focirevealed a hypersensitivity to doses below 0.3Gy. Furthermore, aconsiderable amount of foci persisted between fractions. The low dosehypersensitivity was observed throughout the treatment and was alsoobserved for several key parameters further downstream in the DDR-pathway, such as p21-associated checkpoint activation, apoptosisinduction and reduction in basal keratinocyte density (BKD).Furthermore, for dose fractions above 1.0 Gy, a distinct acceleration inDDR was observed half way into treatment. This was manifested as anaccelerated loss of basal keratinocytes, mirrored by a simultaneousincrease in DSBs and p21 expression. Quantifications of mitotic events revealed a pronounced suppression ofmitosis throughout the treatment which was clearly low dosehypersensitive. Thus, no evidence of accelerated repopulation could beobserved for fraction doses ranging from 0.05 to 2Gy. Our results suggest that the keratinocyte response primarily isdetermined by checkpoints, which leads to pre-mitotic cell elimination by permanent growth arrest and apoptosis. A comparison between the epidermal and dermal sub-compartments revealsa consistent up-regulation of the DDR response during treatment. Adifference was however observed in the recovery phase after treatment,where miR-34a and p21 remain up-regulated in dermis more persistentlythan in epidermis. Our observations suggest that the recovery phaseafter treatment can provide important clues to understand clinicalobservations such as the early and late effects observed in normaltissues during fractionated radiotherapy.
176

Dopaminergic Impact on External Brain Stimulation-Induced Neuroplasticity in Human Motor Cortex / Dopaminerge Modulation von Hirnstimulations-induzierter Neuroplastizität im motorischen Kortex des Menschen

Do Monte Silva Machado, Katia Karina 11 June 2009 (has links)
No description available.
177

Corneal injury to ex-vivo eyes exposed to a 3.8 micron laser /

Fyffe, James G. January 2005 (has links) (PDF)
Thesis (M.S.)--Uniformed Services University of the Health Sciences, 2005. / Typescript (photocopy).
178

Verification of Caregraph® peak skin dose data using radiochromic film /

Ozeroglu, Muhammed A. January 2005 (has links) (PDF)
Thesis (M.S.)--Uniformed Services University of the Health Sciences, 2005. / Typescript (photocopy).
179

Effects of clozapine and alprazolam on cognitive deficits and anxiety-like behaviors in a ketamine-induced rat model of schizophrenia /

Phillips, Jennifer M. January 2005 (has links)
Thesis (Ph. D.)--Uniformed Services University of the Health Sciences, 2005. / Typescript (photocopy).
180

Modelo de análise de populações de plantas daninhas resistentes a herbicidas / Model analysis of weed populations resistant to herbicides

Henrique Sadao Kajino 30 September 2011 (has links)
Este trabalho propõe um modelo dinâmico para análise de populações de plantas daninhas resistentes a herbicidas. O modelo representa a dinâmica populacional causada por um aumento na proporção de plantas resistentes a herbicidas, resultante da recombinação genética modificada pela pressão seletiva causada pelo herbicida. O aumento da resistência causa uma diminuição na eficácia da dose aplicada do herbicida sobre toda população e, eventualmente, compromete o controle desta população. São apresentados resultados de simulação da planta daninha Bidens subalternans, resistente ao herbicida nicosulfuron e tolerante ao herbicida atrazine, e da planta daninha Bidens pilosa, resistente ao herbicida chlorimuron-ethyl e tolerante ao herbicida imazetaphyr para diferentes doses de herbicidas. / This paper proposes a dynamic model for analysis of herbicide resistance in weed populations. The model represents population dynamic caused by an increase in the proportion of plants resistant to herbicides, resulting from genetic recombination modified by selective pressure caused by herbicide. The increase of resistance decreases the efficacy of the applied dose of herbicide over the entire population and, eventually compromises the population control. Results of simulation for different doses are presented for the weed Bidens subalternans, resistant to nicosulfuron and tolerant to atrazine, and for the weed Bidens pilosa, resistant to herbicide chlorimuron-ethyl and tolerant to imazetaphyr.

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