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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

Determinants of mammographic parenchymal patterns and implications for breast cancer aetiology : a study in northern Greece (Ormylia Mammography Screening Programme)

Riza, Eleni January 2000 (has links)
No description available.
2

Mätdatainsamling för solceller : Uppbyggnad av en mätnings krets för solceller / Collection of measurement data for solar cells : Construction of a measuring circuit for solar cells

Karlsson, Johan January 2021 (has links)
Glava Energy Center har gett mig i uppdrag att skapa ett system som kan hantera mätdatainsamling för solceller. Projektet går ut på att mäta ström och spänning från solceller och sedan skicka denna mätdata till en metrum instrumentlåda som sedan laddar upp datan till deras databas. Med hjälp av ett mikrokontrollerkort och en IC skapas detta system för att hämta data. Datan kollas sedan via python kod för att se så att den stämmer väl med vad som förväntas. Systemet som utvecklats hittar solcellens MPP inom 20 sekunder. Dock tack vare tidsbrist kan inte systemet skapa den analoga signalen på 4-20mA som krävs för att skicka datan till metrum instrumentlådan. Den teoretiska kretsen är färdig men har inte hunnit implementeras. / <p></p><p></p>
3

Ripple Current Effect on Output Power of Solar Cell

Lin, Shin-Li 25 July 2012 (has links)
This thesis investigates the effect of the ripple current on the output power of solar cells. A solar panel with several metal halide lamps is set up to emulate the photovoltaic power system, which is cascaded by a boost converter and a buck-boost converter to extract triangular and trapezoidal currents, respectively. All experiments are operated under the room temperature with different current ripples and frequencies. The measured current and voltage waveforms at the output powers indicate that the dynamic characteristics are very different from static ones obtained from the dc loads. It is found that the output voltage lags the current when the peak of the rippled current goes beyond the maximum power point (MPP), leading to a declination in the average output power. This phenomenon becomes more severe for a higher peak, lower frequency, and larger charge of the rippled current exceeding the MPP. In addition, the declination in the average power may cause a shift of the MPP.
4

The Mechanisms of Protective Function of DJ-1 in Parkinson’s Models of Neuronal Loss: VHL and PON2

Parsanejad, Mohammad 23 April 2013 (has links)
Parkinson's disease (PD) is the most common neurodegenerative motor disorder, whose clinical features are rest tremor, bradykinesia, muscular rigidity and postural instability. Although most reported cases are sporadic, a handful of familial cases and their causative genes have been identified. Loss-of-function mutations in DJ-1, one of these genes, are responsible for 1% of familial PD cases. Our laboratory has previously reported that DJ-1- lacking neurons are sensitive to oxidative stress, induced by hydrogen peroxide or the neurotoxin MPTP. To investigate the possible mechanisms through which DJ-1 protects against oxidative stress, we performed a proteomic screen and identified Von Hippel Lindau (VHL) and Paraoxonase2 (PON2) as potential DJ-1 interacting partners. VHL is an E3 ubiquitin ligase which, in normal conditions, poly-ubiquitinates HIF-1 , a subunit of a master hypoxic/oxidative stress transcription factor, whose function is protective in oxidative and hypoxic stresses. In the present study, we provided further evidence of interaction of DJ-1 with VHL. We also demonstrated that HIF-1 protein level, as an indicator of VHL activity, is lower in cells lacking DJ-1, suggesting the inhibitory role of DJ-1 on VHL. Our in vitro studies also showed that DJ-1 inhibits ubiquitin ligase activity of VHL on HIF-1 by reducing the VHL-HIF-1 interaction. Importantly, accumulation of HIF-1 protects embryonic cortical neurons against MPP+ induced neuronal death. Finally, we confirmed the impairment of HIF-1 response to oxidative stress in human lymphoblastoids of DJ-1-linked PD cases. In the second part of this study, we demonstrated the interaction of DJ-1 and PON2. Interestingly, PON2 lactonase activity is reduced in DJ-1 deficient cells which could be rescued by re-introduction of DJ-1, suggesting a modulating role of DJ-1 on PON2 activity. In addition, PON2 deficiency, like DJ-1 deficiency, hypersensitizes neurons to MPP+, which could be rescued by over-expression of PON2 in both cases. Taken together, our data provide evidence that DJ-1 exerts its protective role by inhibiting VHL activity, enhancing HIF-1 stability, and increasing PON2 pro-survival function in PD models.
5

The Mechanisms of Protective Function of DJ-1 in Parkinson’s Models of Neuronal Loss: VHL and PON2

Parsanejad, Mohammad January 2013 (has links)
Parkinson's disease (PD) is the most common neurodegenerative motor disorder, whose clinical features are rest tremor, bradykinesia, muscular rigidity and postural instability. Although most reported cases are sporadic, a handful of familial cases and their causative genes have been identified. Loss-of-function mutations in DJ-1, one of these genes, are responsible for 1% of familial PD cases. Our laboratory has previously reported that DJ-1- lacking neurons are sensitive to oxidative stress, induced by hydrogen peroxide or the neurotoxin MPTP. To investigate the possible mechanisms through which DJ-1 protects against oxidative stress, we performed a proteomic screen and identified Von Hippel Lindau (VHL) and Paraoxonase2 (PON2) as potential DJ-1 interacting partners. VHL is an E3 ubiquitin ligase which, in normal conditions, poly-ubiquitinates HIF-1 , a subunit of a master hypoxic/oxidative stress transcription factor, whose function is protective in oxidative and hypoxic stresses. In the present study, we provided further evidence of interaction of DJ-1 with VHL. We also demonstrated that HIF-1 protein level, as an indicator of VHL activity, is lower in cells lacking DJ-1, suggesting the inhibitory role of DJ-1 on VHL. Our in vitro studies also showed that DJ-1 inhibits ubiquitin ligase activity of VHL on HIF-1 by reducing the VHL-HIF-1 interaction. Importantly, accumulation of HIF-1 protects embryonic cortical neurons against MPP+ induced neuronal death. Finally, we confirmed the impairment of HIF-1 response to oxidative stress in human lymphoblastoids of DJ-1-linked PD cases. In the second part of this study, we demonstrated the interaction of DJ-1 and PON2. Interestingly, PON2 lactonase activity is reduced in DJ-1 deficient cells which could be rescued by re-introduction of DJ-1, suggesting a modulating role of DJ-1 on PON2 activity. In addition, PON2 deficiency, like DJ-1 deficiency, hypersensitizes neurons to MPP+, which could be rescued by over-expression of PON2 in both cases. Taken together, our data provide evidence that DJ-1 exerts its protective role by inhibiting VHL activity, enhancing HIF-1 stability, and increasing PON2 pro-survival function in PD models.
6

THE MARGIN PROTECTION PROGRAM FOR DAIRY: A FORECAST & AD HOC REGIONAL ANALYSIS

Richard, Jessica A. G. 01 January 2017 (has links)
This study examined The Margin Protection Program for Dairy’s impact on the “effective margins” or margins realized by dairy producers in various regions. Each selected margin and percentage of production history offered by the national policy was analyzed in a forecasting, national and regional manner. Couplet margins were simulated for fifteen regions from 2017 through 2020. Five scenarios were analyzed for the change in MPP’s effects under a 15%, 10%, and 5% drop in the price of milk as well as a 50% increase in the price of corn and a scenario where milk decreases 15% while corn prices simultaneously increases 25%. The results demonstrate that more than half of the regions have higher probabilities of triggering indemnities at every coverage level when compared to the US, MPP margin. Margins change in response to the policy effects, where lower coverage levels experience margin increase, and higher coverage levels experience margin decrease. In the US, MPP margin, risk reduction is observed at every coverage level. The program was found to decrease risk at most coverage levels, where higher shocks to the margin increased the protection offered by the program’s effects.
7

Mecanismes de neurodegeneració i neuroprotecció en models de parkinsonisme en rata

Cutillas Arroyo, Blanca 08 March 2012 (has links)
Per a modelar alguns aspectes bioquímics i anatomopatològics de la malaltia de Parkinson en la rata, en aquesta tesi hem començant utilitzant la neurotoxina MPP+, de relativament recent aparició i la més veterana 6-OHDA i hem acabat emprant el propi neurotransmissor de les neurones que degeneren, la dopamina, intentant esbrinar els seus mecanismes de lesió. L’estudi s’ha iniciat en el animal in vivo, ha continuat en talls gruixuts de teixit ex vivo i ha acabat en mitocondris in vitro. Hem volgut reproduir resultats d’altres grups però amb abordat¬ges experimentals més senzills i econòmics, al nostre abast. Hem volgut aplicar el nostre model animal per a estudis comparatius amb la malaltia humana Per a la introducció he partit d’uns 50 articles de revisió actualitzats, amb la voluntat d’adquirir una visió panoràmica de la malaltia de Parkinson: les hipòtesis etiopatogèniques, les manifestacions clíniques, els trets anatomopatològics i bioquímics, així com dels models animals que s’utilitzen per a reproduir-la. En aquests articles he trobat les referències biblogràfiques per aprofundir en els aspectes més directament relacionats amb els experiments realitzats. Per als resultats, que s’han de contemplar dins el marc de la participació en projectes dels nostre grup i d’altres que utilitzaven aquests models animals d’experimentació, hem triat aquells en els que he participat directament, treballs que en alguns casos han estat els preliminars per altres treballs de doctorat del grup. Pràcticament tots els resultats que presentem han estat publicats, com article, en revistes internacionals, aquí queden recollits en l’apartat d’annexes, raó per la qual en la introducció general no consten alguns conceptes introductoris que apareixen en cadascun d’ells.
8

Studium mitochondriálních procesovacích peptidáz u procyklických stádií \kur{Trypanosoma brucei} / Study of mitochondrial processing peptidases in procyclic \kur{Trypanosoma brucei}

POLIAK, Pavel January 2010 (has links)
Aim of this work was to find out how mitochondrial processing peptidases are working in the mitochondrion of Trypanosoma brucei. I have shown by RNA interference that mitochondrial processing peptidase (MPP) and mitochondrial intermediate peptidase (MIP) are essential for procyclic stages. Moreover, processing of human frataxin in T. brucei has a similar pattern as in human cells.
9

Vliv inhibice SIRT1 na morfologii a chování Dánia pruhovaného / The impact of SIRT1 inhibition on zebrafish morphology and behavior

Faustová, Zuzana January 2013 (has links)
Charles University in Prague Faculty of Pharmacy in Hradec Králové Department of Pharmacology & Toxicology Student: Zuzana Faustová Supervisor: Prof. Doutor Jorge Miguel de Ascenção Oliveira PharmDr. Lukáš Červený, Ph.D. Title of diploma thesis: The impact of SIRT1 inhibition on zebrafish morphology and behavior After discovery of connection between yeast Silent Information Regulator 2 (Sir2) and its ability to alter lifespan, Sir2 and its seven mammalian orthologs became very attractive therapeutic target. These so called sirtuins are members of a histone deacetylase family. They possess unique catalytic activity having nicotinamide adenine dinucleotide as a cofactor and their function can be influenced by environmental factors. The aim of this diploma thesis was to extend knowledge of Sirtuin 1 (SIRT1), which is from all mammalian sirtuins considered to have the closest relation to yeast Sir2. At first we tested the impact of SIRT1 inhibition on early developmental stages of zebrafish (Danio rerio) embryos and larvae, finding out that SIRT1 is important for normal development and SIRT1 inhibition or malfunction result in cardiovascular defects, delayed development, and death. Additionally, we tried to learn more about SIRT1 and its connection with Parkinson's disease by combining nontoxic doses...
10

Neurotoxin Mechanisms and Processes Relevant to Parkinson’s Disease: An Update

Segura-Aguilar, Juan, Kostrzewa, Richard M. 01 April 2015 (has links)
The molecular mechanism responsible for degenerative process in the nigrostriatal dopaminergic system in Parkinson’s disease (PD) remains unknown. One major advance in this field has been the discovery of several genes associated to familial PD, including alpha synuclein, parkin, LRRK2, etc., thereby providing important insight toward basic research approaches. There is an consensus in neurodegenerative research that mitochondria dysfunction, protein degradation dysfunction, aggregation of alpha synuclein to neurotoxic oligomers, oxidative and endoplasmic reticulum stress, and neuroinflammation are involved in degeneration of the neuromelanin-containing dopaminergic neurons that are lost in the disease. An update of the mechanisms relating to neurotoxins that are used to produce preclinical models of Parkinson´s disease is presented. 6-Hydroxydopamine, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, and rotenone have been the most wisely used neurotoxins to delve into mechanisms involved in the loss of dopaminergic neurons containing neuromelanin. Neurotoxins generated from dopamine oxidation during neuromelanin formation are likewise reviewed, as this pathway replicates neurotoxin-induced cellular oxidative stress, inactivation of key proteins related to mitochondria and protein degradation dysfunction, and formation of neurotoxic aggregates of alpha synuclein. This survey of neurotoxin modeling—highlighting newer technologies and implicating a variety of processes and pathways related to mechanisms attending PD—is focused on research studies from 2012 to 2014.

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