Doctor of Philosophy

dissertationSeveral studies have demonstrated an association between prediabetes (preDM) and the incidence of Type II Diabetes Mellitus (T2DM). Many preventable factors can contribute to this association, namely behavioral and environmental conditions that lead to physiological changes and symptomology. Earlier identification of disease through combining common laboratory studies that demonstrate an elevated fasting glucose may be one mechanism to identify the vast majority of patients who are unaware of their preDM condition. Also, it has been widely demonstrated that T2DM can be effectively prevented or delayed with interventions geared towards weight management, physical activity, goal setting, and stress management. However, it is not entirely known whether education provided within a healthcare delivery system is effective in supporting patients to reach a 5% weight loss while reducing their overall incidence of T2DM disease. Furthermore, study is needed to evaluate such health interventions beyond effectiveness, to better identify effect and transferability through measuring the reach, adoption, and implementation. The objective of this dissertation was to determine: (a) the risk of T2DM among patients with confirmed and unconfirmed preDM relative to an at-risk group; (b) the association of a 5% weight loss with participation in the Intermountain Healthcare (IH) Diabetes Prevention Program (DPP); and, subsequently, (c) the reach, effectiveness, adoption, and implementation of the IH DPP intervention. The IH Enterprise Data Warehouse was utilized to evaluate these objectives. Patients with unconfirmed preDM iv (HR 1.74; CI 1.59, 1.91; p<0.0001) and confirmed preDM (HR 2.77; CI 2.38, 3.23; p<0.0001) were more likely to develop T2DM when compared to at-risk patients. DPP participants were more likely to achieve a 5% weight loss within 6 months (OR 1.72; 95% CI 1.29, 2.34; p<0.001) and less likely to have incident T2DM (OR 0.45; 95% CI 0.24, 0.84; p=0.012) when compared to the no-DPP group. Lastly, DPP-based lifestyle interventions deployed within IH's delivery system demonstrated moderate effectiveness in the short term, yet the proportion of patients (8%) who enrolled was low. Broad adoption across regions by providers and leadership revealed organizational buy-in (194 providers at 53 clinics referred patients), while demonstrating that much of the clinical effect was seen when patients participated in interventions that were far less resource intensive (only 2.3 DPP counseling encounters on average). In conclusion, confirmed and unconfirmed preDM was associated with T2DM, however when patients participated in a DPP-based intervention, there was significant weight loss and reduction in T2DM incidence. Finally, the IH DPP demonstrated encouraging potential when evaluating organizational adoption and short-term effectiveness, yet may benefit from leveraging technology to scale these established interventions for those at risk for disease

The Gain of Network Coding in Wireless Sensor Networking

Wireless Sensor Networks have some well known features such as low battery consumption, changing topology awareness, open environment, non reliable radio links, etc.In this paper, we investigate the benefits of Network Coding Wireless Sensor networking, especially resiliency.One of our main concern is the resiliency in Wireless Sensor Networks.We have seen that resiliency could be described as a multi dimensional metric \cite{5478822,erdene2011enhancing,6423640} taking parameters such as Average Delivery Ratio, Delay Efficiency, Energy Efficiency, Average Throughput and Delivery Fairness into account.Resiliency can then be graphically represented as a kiviat diagram created by the previous weighted parameters.In order to introduce these metrics, previous works have been leaded on the Random Gradient Based Routing, which proved good resiliency in malicious environment.We look for seeing the improvements in term of resiliency, when adding network coding in the Random Gradient Based Routing with malicious nodes

Selective solubilization of chlorosome proteins in Chloroflexus aurantiacus

AbstractProteins were solubilized selectively from chlorosomes of Chloroflexus aurantiacus by electrophoretic gel filtration according to Griebenow et al. Whereas the 11 kDa and 18 kDa proteins were extracted almost completely, the remaining modified chlorosomes contained high amounts of pigment and c-protein. It was concluded that the c-protein in contradiction to the publication by Griebenow et al. is indeed localized in the interior of Chloroflexus chlorosomes

The complete amino acid sequence of the antenna polypeptide B806-866-β from the cytoplasmic membrane of the green bacterium Chloroflexus auranliacus

AbstractThe bacteriochlorophyll a-binding polypeptide B806–866-β was extracted from membranes of the green thermophilic bacterium Chloroflexus aurantiacus with chloroform/methanol/ammonium acetate. Purification of the antenna polypeptide (6.3 kDa) was achieved by chromatography on Sephadex LH-60, Whatman DE-32 and by FPLC. The complete amino acid sequence (53 amino acid residues) was determined. The B806–866-β polypeptide is sequence homologous to the antenna β-polypeptides of purple bacteria (27–40%) and exhibits the characteristic three domain structure of the B870, B800–850 and B800–820 antenna complexes. The two typical His residues, conserved in all antenna β-polypeptides of purple bacteria, were found: His-24 lies within the N-terminal hydrophilic domain and His-42 within the central hydrophobic domain. This polypeptide together with the previously described α-polypeptide form the basic structural unit of the B806–866 antenna complex from C. aurantiacus

CIRCULAR DICHROISM OF LIGHT-HARVESTING COMPLEXES FROM PURPLE PHOTOSYNTHETIC BACTERIA

The CD spectra of a range of antenna complexes from several different species of purple photosynthetic bacteria were recorded in the wavelength range of 190 to 930 nm. Analysis of the far UV CD (190 to 250 nm) showed that in each case except for the B800-850 from Chr. vinosum the secondary structure of the light-harvesting complexes contains a large amount of α-helix (50%) and very little 0-pleated sheet. This confirms the predictions of the group of Zuber of a high a-helical content based upon consideration of the primary structures of several antenna apoproteins. The CD spectra from the carotenoids and the bacteriochlorophylls show considerable variations depending upon the type of antenna complex. The different amplitude ratios in the CD spectrum for the bacteriochlorophyll Qy, Qx and Soret bands indicate not only different degrees of exciton coupling, but also a strong and variable hyperchromism (Scherz and Parson, 1984a, b)

A new possible binding site for bacteriochlorophyll b in a light-harvesting polypeptide of the bacterium Ectothiorhodospira halochloris

AbstractWhole cells from Ectothiorhodospira halochloris were extracted with an organic solvent mixture. At least five small hydrophobic polypeptides representing most probably the light harvesting polypeptides were purified by gel filtration and consecutive FPLC-RP chromatography. The complete amino acid sequence of a 7.4 kDa polypeptide was determined. The polypeptide shows a three domain structure, indicative of an integral membrane protein, similar to the structure of the light-harvesting polypeptides from purple non-sulfur bacteria. Sequence homologies to the β-LHPs of purple bacteria range from 23. 1° to 36.4°. The conserved intramembrane located histidine residue of the antenna polypeptides of purple non-sulfur bacteria, assigned as the possible binding site for bacteriochlorophyll, was found to be replaced by asparagine

Tumor suppressor fumarate hydratase is phosphorylated and regulated by AMP-activated protein kinase

International audienc

Anatomie des retransmissions dans les implémentations de 802.11

National audienceNous analysons les retransmissions pour plusieurs modèles de carte Wi-Fi. Pour cela, nous avons mis en place un protocole expérimental permettant de collecter des données, qui sont ensuite analysées et comparées au comportement idéal spécifié par le standard IEEE 802.11. Nous constatons des comportements tous différents, qui peuvent en partie expliquer les pertes de connectivité lors des phases de mobilité

Metabolic Cleavage and Translocation Efficiency of Selected Cell Penetrating Peptides: A Comparative Study with Epithelial Cell Cultures

We investigated the metabolic stability of four cell penetrating peptides (CPPs), namely SAP, hCT(9-32)-br, [Pα] and [Pβ], when in contact with either subconfluent HeLa, confluent MDCK or Calu-3 epithelial cell cultures. Additionally, through analysis of their cellular translocation efficiency, we evaluated possible relations between metabolic stability and translocation efficiency. Metabolic degradation kinetics and resulting metabolites were assessed using RP-HPLC and MALDI-TOF mass spectrometry. Translocation efficiencies were determined using fluorescence-activated cell sorting (FACS) and confocal laser scanning microscopy (CLSM). Between HeLa, MDCK and Calu-3 we found the levels of proteolytic activities to be highly variable. However, for each peptide, the individual degradation patterns were quite similar. The metabolic stability of the investigated CPPs was in the order of CF-SAP = CF-hCT(9-32)-br > [Pβ]−IAF > [Pα] and we identified specific cleavage sites for each of the four peptides. Throughout, we observed higher translocation efficiencies into HeLa cells as compared to MDCK and Calu-3, corresponding to the lower state of differentiation of HeLa cell cultures. No direct relation between metabolic stability and translocation efficiency was found, indicating that metabolic stability in general is not a main limiting factor for efficient cellular translocation. Nevertheless, translocation of individual CPPs may be improved by structural modifications aiming at increased metabolic stabilit

Coagulation at the blood-electrode interface: the role of electrochemical desorption and degradation of fibrinogen

The influence of electrochemistry on the coagulation of blood on metal surfaces was demonstrated several decades ago. In particular, the application of cathodic currents resulted in reduced surface thrombogenicity, but no molecular mechanism has been so far proposed to explain this observation. In this article we used for the first time the quartz crystal microbalance with dissipation monitoring technique coupled with an electrochemical setup (EQCM-D) to study thrombosis at the blood-electrode interface. We confirmed the reduced thrombus deposition at the cathode, and we subsequently studied the effect of cathodic currents on adsorbed fibrinogen (Fg). Using EQCM and mass spectrometry, we found that upon applying currents Fg desorbed from the electrode and was electrochemically degraded. In particular, we show that the flexible N-terminus of the α-chain, containing an important polymerization site, was cleaved from the protein, thus affecting its clottability. Our work proposes a molecular mechanism that at least partially explains how cathodic currents reduce thrombosis at the blood-electrode interface and is a relevant contribution to the rational development of medical devices with reduced thrombus formation on their surface