115 research outputs found
Djelovanje karboksilnih kiselina na crveno obojenje cvjetova žutinice
Eight carboxylic acids were fed at 1-10000 pM to the flower pastes from fresh dyer’s saffron (Carthamus tinctorius L.) capitula and their effects on the red colouration investigated. Glyoxyllic acid, glycolic acid, oxaloacetic acid, 2-oxoglutaric acid and gluconic acid were found to be positive stimulators for the reaction, while succinic acid, malic acid and citric acid inhibited the colour change.Svojim ranijim istraživanjima autori su pokazali da usitnjeni cvjetovi žutinice (Carthamus tinctorius L.) poprime crvenu boju ako na njih djeluju otopine aminokiselina. Učinkovitost pojedine aminokiseline ovisi o tipu: kisele amino- kiseline bile su najučinkovitije, neutralne nešto manje, one s aromatičnim skupinama ili skupinama sa sumporom još manje, dok su bazične aminokiseline bile najmanje učinkovite. Za objašnjenje ovih rezultata bilo je potrebno da se ustanove još drugi metaboliti koji biokatalitički utječu na promjenu boje cvjetova. U ovom prilogu autori objavljuju podatke o promjenama boje nakon primjene karboksilnih kiselina.
U tu svrhu istražili su djelovanje osam karboksilnih kiselina u koncentracijama od 1 - 10000 pM na kašu od zdrobljenih cvjetova žutinice (Carthamus tinctorius L.). Postignuti rezultati su pokazali da glioksilna, glikolna, oksalooc- tena, 2-oksoglutarna i glukonska kiselina pospješuju reakciju stvaranja crvenog bojila, dok jantarna, jabučna i limunska kiselina tu reakciju inhibiraju. U radu se navode točni podaci o materijalu, metodama rada i rezultatima koji su prikazani u preglednoj tabeli. Rezultate autori kratko komentiraju uz razmišljanja da bi kemijske strukture karboksilnih kiselina mogle biti uže povezane s procesima promjene bojila, iako je sam mehanizam reakcije zasad još nepoznat
2012 Activity Report of the Regional Research Programme on Hadrontherapy for the ETOILE Center
2012 is the penultimate year of financial support by the CPER 2007-2013 for ETOILE's research program, sustained by the PRRH at the University Claude Bernard. As with each edition we make the annual review of the research in this group, so active for over 12 years now. Over the difficulties in the decision-making process for the implementation of the ETOILE Center, towards which all our efforts are focussed, some "themes" (work packages) were strengthened, others have progressed, or have been dropped. This is the case of the eighth theme (technological developments), centered around the technology for rotative beam distribution heads (gantries) and, after being synchronized with the developments of ULICE's WP6, remained so by ceasing its activities, coinciding also with the retirement of its historic leader at IPNL, Marcel Bajard. Topic number 5 ("In silico simulations") has suffered the departure of its leader, Benjamin Ribba, although the work has still been provided by Branka Bernard, a former postdoctoral fellow in Lyon Sud, and now back home in Croatia, still in contract with UCBL for the ULICE project. Aside from these two issues (and the fact that the theme "Medico-economical simulations" is now directly linked to the first one ("Medical Project"), the rest of the teams are growing, as evidenced by the publication statistics at the beginning of this report. This is obviously due to the financial support of our always faithful regional institutions, but also to the synergy that the previous years, the European projects, the arrival of the PRIMES LabEx, and the national France Hadron infrastructure have managed to impulse. The Rhone-Alpes hadron team, which naturally includes the researchers of LPC at Clermont, should also see its influence result in a strong presence in France Hadron's regional node, which is being organized. The future of this regional research is not yet fully guaranteed, especially in the still uncertain context of ETOILE, but the tracks are beginning to emerge to allow past and present efforts translate into a long future that we all want to see established. Each of the researchers in PRRH is aware that 2013 will be (and already is) the year of great challenge : for ETOILE, for the PRRH, for hadron therapy in France, for French hadrontherapy in Europe (after the opening and beginning of treatments in the German [HIT Heidelberg, Marburg], Italian [CNAO, Pavia] and Austrian [MedAustron, Wien Neuerstadt]) centers. Let us meet again in early 2014 for a comprehensive review of the past and a perspective for the future ..
RLIP76, a Glutathione-Conjugate Transporter, Plays a Major Role in the Pathogenesis of Metabolic Syndrome
PURPOSE: Characteristic hypoglycemia, hypotriglyceridemia, hypocholesterolemia, lower body mass, and fat as well as pronounced insulin-sensitivity of RLIP76⁻/⁻ mice suggested to us the possibility that elevation of RLIP76 in response to stress could itself elicit metabolic syndrome (MSy). Indeed, if it were required for MSy, drugs used to treat MSy should have no effect on RLIP76⁻/⁻ mice. RESEARCH DESIGN AND METHODS: Blood glucose (BG) and lipid measurements were performed in RLIP76⁺/⁺ and RLIP76⁻/⁻ mice, using Ascensia Elite Glucometer® for glucose and ID Labs kits for cholesterol and triglycerides assays. The ultimate effectors of gluconeogenesis are the three enzymes: PEPCK, F-1,6-BPase, and G6Pase, and their expression is regulated by PPARγ and AMPK. The activity of these enzymes was tested by protocols standardized by us. Expressions of RLIP76, PPARα, PPARγ, HMGCR, pJNK, pAkt, and AMPK were performed by Western-blot and tissue staining. RESULTS: The concomitant activation of AMPK and PPARγ by inhibiting transport activity of RLIP76, despite inhibited activity of key glucocorticoid-regulated hepatic gluconeogenic enzymes like PEPCK, G6Pase and F-1,6-BP in RLIP76⁻/⁻ mice, is a salient finding of our studies. The decrease in RLIP76 protein expression by rosiglitazone and metformin is associated with an up-regulation of PPARγ and AMPK. CONCLUSIONS/SIGNIFICANCE: All four drugs, rosiglitazone, metformin, gemfibrozil and atorvastatin failed to affect glucose and lipid metabolism in RLIP76⁻/⁻ mice. Studies confirmed a model in which RLIP76 plays a central role in the pathogenesis of MSy and RLIP76 loss causes profound and global alterations of MSy signaling functions. RLIP76 is a novel target for single-molecule therapeutics for metabolic syndrome
Comparaison par simulation Monte-Carlo de l'imagerie X et de l'imagerie proton pour le calcul de dose en protonthérapie
National audienceDans la pratique clinique actuelle, l'estimation de la dose délivrée dans le plan de traitement en protonthérapie se base sur une carte des coefficients d'atténuation reconstruite à partir d'une image par rayons X puis convertie en carte de pouvoir d'arrêt relatif (RSP). Cependant, comme il n'y a pas de relation unique entre les unités Hounsfield et le RSP, cette étape d'étalonnage impose d'augmenter les marges d'incertitudes sur le parcours des protons de l'ordre de 2.5%+1mm à 3.5%+3mm selon le centre de protonthérapie. L'imagerie proton (pCT) peut permettre une meilleure estimation de la dose délivrée en protonthérapie via une reconstruction directe de la carte de pouvoir d'arrêt des tissus. L'autre avantage de cette technique est de permettre une réduction de la dose délivrée pour l'acquisition des images en comparaison de l'imagerie X. Plusieurs études ont déjà démontré les capacités de l'imagerie proton à estimer précisément la carte de pouvoir d'arrêt, mais il y a encore un manque d'études permettant de quantifier réellement l'avantage clinique de l'imagerie proton en comparaison de l'imagerie X. Nous avons pour cela développé une étude basée sur la simulation Monte-Carlo (Geant4) présentant un plan de traitement complet en protonthérapie dans le but de quantifier la précision des calculs de dose délivrée dans le cas de l'imagerie X et de l'imagerie proton. Cette étude est basée sur un fantôme numérique (ICRP 110) imagé à la fois avec une simulation d'un scanner X et d'un scanner proton. Les images proton sont reconstruites par un algorithme de rétroprojection filtrée développé récemment par l'équipe de CREATIS pour tenir compte du parcours complexe des protons dans les tissus [1]. Pour être le plus proche possible des pratiques cliniques, un fantôme permettant la caractérisation des tissus (Gammex 467) est également simulé pour produire la courbe d'étalonnage nécessaire à la conversion des unités Hounsfield en unité de pouvoir d'arrêt dans le cas de l'imagerie X. Les cartes de pouvoir d'arrêt des tissus obtenues à partir des images X et proton sont comparées à une carte de référence correspondant au fantôme ICRP. Une procédure unique permet ensuite de transformer ces cartes en équivalent tissus (densité, composition) afin de pouvoir simuler la dose délivrée dans le cas d'un traitement en protonthérapie. Les premiers résultats obtenus démontrent qu'à dose identique (quelques mGy), l'imagerie proton permet une estimation plus précise du parcours des protons que l'imagerie X. Cette étude innovante permet ainsi de quantifier à la fois la précision des cartes de pouvoir d'arrêt reconstruites et l'impact sur l'estimation de la dose délivrée dans le cas d'un traitement en protonthérapie utilisant l'imagerie proton. Reference : [1] S. Rit et al. (2013). 'Filtered backprojection proton CT reconstruction along most likely paths', Med Phys 40(3)
A systematic study of structure and E-H bond activation chemistry by sterically encumbered germylene complexes
A series of new germylene compounds has been synthesized offering systematic variation in the σ- and π- capabilities of the α-substituent, and differing levels of reactivity towards E-H bond activation (E = H, B, C, N, Si, Ge). Chloride metathesis utilizing (terphenyl)GeCl proves to be an effective synthetic route to complexes of the type (terphenyl)Ge(ERn) [1-6: ERn = NHDipp, CH(SiMe3)2, P(SiMe3)2, Si(SiMe3)3 or B(NDippCH)2; terphenyl = C6H3Mes2-2,6 = ArMes or C6H3Dipp2-2,6 = ArDipp], while the related complex {(Me3Si)2N}Ge{B(NDippCH)2} (8) can be accessed via an amide/boryl exchange route. Metrical parameters have been probed by X-ray crystallography, and are consistent with widening angles at the metal centre as more bulky and/or more electropositive substituents are employed. Thus, the widest germylene units (θ > 110o ) are found to be associated with strongly σ-donating boryl or silyl ancillary donors. HOMO-LUMO gaps for the new germylene complexes have been appraised by DFT calculations. The aryl(boryl) -germylene system ArMesGe{B(NDippCH)2} (6-Mes), which features a wide C-Ge-B angle [110.4(1)°] and (albeit relatively weak) ancillary π-acceptor capabilities, has the smallest HOMO-LUMO gap (119 kJ mol-1 ). These features result in 6-Mes being remarkably reactive, undergoing facile intramolecular C-H activation involving one of the mesityl ortho-methyl groups. The related aryl(silyl)- germylene system, ArMesGe{Si(SiMe3)3} (5-Mes) has a marginally wider HOMO-LUMO gap (134 kJ mol-1 ), rendering it less labile towards decomposition, yet reactive enough to oxidatively cleave H2 and NH3 to give the corresponding dihydride and (amido)hydride. Mixed aryl/alkyl, aryl/amido and aryl/phosphido complexes are unreactive, but amido/boryl complex 8 is competent for the activation of E-H bonds (E = H, B, Si) to give hydrido, boryl and silyl products. The results of these reactivity studies imply that the use of the very strongly σ-donating boryl or silyl substituents is an effective strategy for rendering metallylene complexes competent for E-H bond activation. </p
EP-2013 Lung tumor motion based on 4D-CBCT: baseline shift, interfraction amplitude and volume variation
International audienc
In-room breathing motion estimation from limited projection views using a sliding deformation model
In-silico comparison of X-ray and proton computed tomography for proton therapy dose simulation with a full Monte Carlo treatment planning
International audienceProton therapy treatment efficiency directly relies on the proton range derived from tissue-relative stopping power (RSP) maps. In clinical practice, RSP is obtained from the conversion of X-ray CT Hounsfield units. This calibration step introduces uncertainties on the dose distribution. Proton computed tomography (pCT) has the potential to improve the accuracy of the proton therapy treatment by a direct derivation of RSP maps. This study aims to quantify the dosimetric accuracy of pCT. A full Monte Carlo proton therapy treatment planning has been developed. Both X-ray and proton CT images of a human computional phantom are simulated with an equivalent 2mGy dose. RSP maps are derived from both images and used to estimate the dose distribution. RSP maps derived from pCT are significantly more accurate and less sensitive to common X-ray artefacts. Proton CT based treatment enables a more precise proton range estimate of about 3-4%. This Monte Carlo method can be applied to any clinical case in order to estimate the expected margins reduction of a proton therapy treatment planning based on pCT
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