159 research outputs found
Visible And Near Infrared Spectroscopy For PSE-Like Zones Classification At Different Post Mortem Times
International audienceâ The ability of visible and near infrared spectroscopy (VIS-NIRS) to predict PSE-like zone classification was examined on 150 deboned hams at 5 post mortem times (12, 16, 20, 24 and 36 h pm). Four probes were used to investigate the accuracy. Two of our probes were prototypes. Partial Least Squares Discriminant Analysis (PLSDA) was used to determine the prediction models from spectrums recorded on semimembranosus muscle. Surface probes gave better results than inserted probes. The best probe showed moreover a good accuracy whatever the pm times was when measuring (78 to 86 % good prediction in external validation as the 24 h pm model was used). Its false negative/false positive ratios were favorable at the early pm times (12 to 20 h pm). So an early PSE-like zones prediction is possible using VIS-NIRS. The prototype probe inserted showed good results (82,9% good prediction in external validation) and would deserve additional validation on bone-in hams, as industrials need. Key Words â VIS-NIR spectroscopy, prototype probes, pork meat, PSE-like zones, PLSDA
"La sensaciĂłn de la soledad" en las Rimas de BĂ©cquer (AproximaciĂłn a la poesĂa metafĂsica)
In our article we try to approximate to the topic of Spanish romanticism and the cosmovision of Gustavo Adolfo BĂ©cquer in particular. We evaluate the role of universal romantic symptom â the feeling of loneliness in BĂ©cquerâs Rimas and observe how his poetic world is linked to the existensial vision of Miguel de Unamuno.En nuestro artĂculo intentamos acercarnos al tema del romanticismo español, y a la visiĂłn romĂĄntica de Gustavo Adolfo BĂ©cquer en particular. Dentro de ello investigamos el papel del sĂntoma universal del romanticismo â la sensaciĂłn de la soledad en las Rimas de BĂ©cquer y observamos cĂłmo estĂĄ vinculado su mundo romĂĄntico con la visiĂłn existencialista de Miguel de Unamuno
Prédiction du rendement technologique des jambons par spectroscopie optique : mise en place et validation en contexte industriel
Session 7 - Green & Biophotonique (C7.2)International audiencePrĂ©diction du rendement technologique des jambons par spectroscopie optique : mise en place et validation en contexte industriel Le rendement de fabrication des jambons est un enjeu pour l'industrie agro-alimentaire : une valeur faible de ce rendement dit technologique se traduit par une dĂ©prĂ©ciation de valeur et de qualitĂ© des jambons [1]. Le tri des carcasses pour la rĂ©alisation des jambons cuits supĂ©rieurs s'appuie sur une mesure de pH mais n'est pas optimal en terme de rĂ©sultats, c'est pour cette raison que l'on essaie de lui substituer une mesure par spectromĂštrie. Dans ce but, un projet a Ă©tĂ© mis en place mettant en oeuvre une chaĂźne de mesure complĂšte. Il suppose le design de plusieurs sondes de surface et de pĂ©nĂ©tration (afin d'explorer un site de mesure optimisĂ© en profondeur et orientation), la mise en oeuvre d'un spectromĂštre (gamme visible et proche infra-rouge cf. Figure 1), puis du traitement de spectre par une mĂ©thode d'apprentissage automatique (Partial Least Square PLS cf. [2]), et l'affichage des rĂ©sultats et de leur communication au sein du rĂ©seau informatique de l'industriel abatteur. Figure 1: MatĂ©riel utilisĂ© : sonde de pĂ©nĂ©tration, spectromĂštre ASD Labspec, sonde de surface (connectique SMA) 2. Aspects historiques et objectifs L'utilisation, dans le cadre d'un projet de recherche, d'un spectromĂštre requiĂšre en gĂ©nĂ©ral une phase de collecte des donnĂ©es, suivi d'une phase d'analyse (calibration du modĂšle) de ces donnĂ©es afin de bĂątir un modĂšle de prĂ©diction Ă l'aide de descripteurs objectifs fournis par ailleurs. Le spectromĂštre est un appareil connectĂ© Ă un PC et comprenant un logiciel spĂ©cifique en charge de rĂ©aliser les opĂ©rations d'acquisition des spectres. Les spectres collectĂ©s sont en gĂ©nĂ©ral transfĂ©rĂ©s sur un autre ordinateur afin d'y ĂȘtre traitĂ©s par un logiciel dĂ©diĂ© Ă l'analyse statistique, une exportation des donnĂ©es dans un format exploitable par ce logiciel est souvent nĂ©cessaire. En routine, l'exploitation du modĂšle statistique issue de la calibration permet pour chaque spectre le calcul d'un ou plusieurs paramĂštres pertinents utilisable en tant que critĂšre de sĂ©lection et de tri des jambons analysĂ©s
The Human Lung Adenocarcinoma Cell Line EKVX Produces an Infectious Xenotropic Murine Leukemia Virus
The cell lines of the NCI-60 panel represent different cancer types and have been widely utilized for drug screening and molecular target identification. Screening these cell lines for envelope proteins or gene sequences related to xenotropic murine leukemia viruses (X-MLVs) revealed that one cell line, EKVX, was a candidate for production of an infectious gammaretrovirus. The presence of a retrovirus infectious to human cells was confirmed by the cell-free transmission of infection to the human prostate cancer cell line LNCaP. Amplification and sequencing of additional proviral sequences from EKVX confirmed a high degree of similarity to X-MLV. The cell line EKVX was established following passage of the original tumor cells through nude mice, providing a possible source of the X-MLV found in the EKVX cells
Reticular dysgenesis-associated AK2 protects hematopoietic stem and progenitor cell development from oxidative stress.
Adenylate kinases (AKs) are phosphotransferases that regulate the cellular adenine nucleotide composition and play a critical role in the energy homeostasis of all tissues. The AK2 isoenzyme is expressed in the mitochondrial intermembrane space and is mutated in reticular dysgenesis (RD), a rare form of severe combined immunodeficiency (SCID) in humans. RD is characterized by a maturation arrest in the myeloid and lymphoid lineages, leading to early onset, recurrent, and overwhelming infections. To gain insight into the pathophysiology of RD, we studied the effects of AK2 deficiency using the zebrafish model and induced pluripotent stem cells (iPSCs) derived from fibroblasts of an RD patient. In zebrafish, Ak2 deficiency affected hematopoietic stem and progenitor cell (HSPC) development with increased oxidative stress and apoptosis. AK2-deficient iPSCs recapitulated the characteristic myeloid maturation arrest at the promyelocyte stage and demonstrated an increased AMP/ADP ratio, indicative of an energy-depleted adenine nucleotide profile. Antioxidant treatment rescued the hematopoietic phenotypes in vivo in ak2 mutant zebrafish and restored differentiation of AK2-deficient iPSCs into mature granulocytes. Our results link hematopoietic cell fate in AK2 deficiency to cellular energy depletion and increased oxidative stress. This points to the potential use of antioxidants as a supportive therapeutic modality for patients with RD
Blocking TGF-ÎČ signaling pathway preserves mitochondrial proteostasis and reduces early activation of PDGFRÎČ+ pericytes in aristolochic acid induced acute kidney injury in wistar male rats
The platelet-derived growth factor receptor ÎČ (PDGFRÎČ)+ perivascular cell activation becomes increasingly recognized as a main source of scar-associated kidney myofibroblasts and recently emerged as a new cellular therapeutic target.In this regard, we first confirmed the presence of PDGFRÎČ+ perivascular cells in a human case of end-stage aristolochic acid nephropathy (AAN) and thereafter we focused on the early fibrosis events of transforming growth factor ÎČ (TGFÎČ) inhibition in a rat model of AAN.Neutralizing anti-TGFÎČ antibody (1D11) and its control isotype (13C4) were administered (5 mg/kg, i.p.) at Days -1, 0, 2 and 4; AA (15 mg/kg, sc) was injected daily.At Day 5, 1D11 significantly suppressed p-Smad2/3 signaling pathway improving renal function impairment, reduced the score of acute tubular necrosis, peritubular capillaritis, interstitial inflammation and neoangiogenesis. 1D11 markedly decreased interstitial edema, disruption of tubular basement membrane loss of brush border, cytoplasmic edema and organelle ultrastructure alterations (mitochondrial disruption and endoplasmic reticulum edema) in proximal tubular epithelial cells. Moreover, 1D11 significantly inhibited p-PERK activation and attenuated dysregulation of unfolded protein response (UPR) pathways, endoplasmic reticulum and mitochondrial proteostasis in vivo and in vitro.The early inhibition of p-Smad2/3 signaling pathway improved acute renal function impairment, partially prevented epithelial-endothelial axis activation by maintaining PTEC proteostasis and reduced early PDGFRÎČ+ pericytes-derived myofibroblasts accumulation
Amplification macroscopique de mouvements nanométriques induits par des machines moléculaires
The last twenty years have seen tremendous progresses in the design and synthesis of complex molecular machines, often inspired by the beauty of the machinery found in biological systems. However, amplification of the molecular machines motion over several orders of magnitude above their typical length scale is still an ambitious challenge. This work describes how self-organization of molecular machines or motors allows for the synthesis of materials translating the motions of their components into a macroscopic response. The three first chapters describe the use of a [c2]daisy chains architecture, a molecule able to perform contraction/extension motions similarly to the sarcomere units of muscles, into systems such as supramolecular polymers and covalent networks. Their inclusion into hydrogen bonding supramolecular polymers based on the uracil:2,6-diacetylaminopyridine recognition motifs combined with lateral interactions such as Ï-stacking provided micrometric muscle-like fibers contracting and extending upon deprotonation and protonation.The incorporation of ureidopyrimidone moieties as supramolecular connectors yielded highly organized gels, which evolved to a liquidstate upon contraction of the polymer chains. Finally, covalent poly[c2]daisy chains were synthesized and investigated, notably the formation of a 3D network swelling into a gel. This material could contract and extend at the macroscopic scale upon contraction and extension of the molecular machines used as monomers. Finally, a fourth chapter is dedicated to the improvement of contractile chemical gels made by using a molecular motor as reticulating nodes. A modulating unit, able to be switched between a âclosedâ and an âopenedâ state, was introduced into the polymer network along with the motor. The locked structure in the âclosedâ state allowed contraction of the gel upon rotation of the molecular motors, while the âopenedâ state allowed unwinding of the entangled polymer chains and extension of the gel when the motor is off. Overall, the work presented in this manuscript demonstrates that carefully designed molecular machines can be incorporated into large supramolecular or covalent assemblies, providing materials which collective motions alter their macroscopic properties. These results provide valuable insights for the elaboration of a new class of muscle-like materials based on molecular machines.Ces vingt derniĂšres annĂ©es, le domaine du design et de la synthĂšse de machines molĂ©culaires complexes a fait dâĂ©normes progrĂšs,souvent inspirĂ© par la beautĂ© de la machinerie prĂ©sente dans les systĂšmes vivants. Cependant, lâamplification des mouvements dâun grand nombre de machines molĂ©culaires Ă des Ă©chelles de tailles largement supĂ©rieures Ă leurs dimensions restent un dĂ©fi thĂ©orique et expĂ©rimental ambitieux et ardu. Ce travail dĂ©crit comment lâorganisation de machines et moteurs molĂ©culaires dans des rĂ©seaux polymĂšres supramolĂ©culaires ou covalents permet de synthĂ©tiser des matĂ©riaux dans lesquels leurs mouvements individuels nanomĂ©triques sont amplifiĂ©s jusquâĂ lâĂ©chelle macroscopique. Les trois premiers chapitres dĂ©crivent lâutilisation dâune architecture de type [c2]daisy chains, une molĂ©cule capable dâeffectuer des contraction/extensions similaires aux mouvements des sarcomĂšres prĂ©sents dans les muscles, dans des rĂ©seaux polymĂšres supramolĂ©culaires et covalents. Leur introduction dans des polymĂšres supramolĂ©culaires Ă liaisons hydrogĂšne basĂ©es sur le motif de reconnaissance uracil:2,6-diacetylaminopyridine associĂ© Ă des interactions latĂ©rales tel que les interactions Ï rĂ©sulta en la formation de fibre supramolĂ©culaires contractiles dont la taille et la morphologie a pu ĂȘtre commutĂ© entre deux Ă©tats Ă©tendus et contractĂ©s. Lâincorporation de motifs urĂ©idopyrimidinone comme connecteur supramolĂ©culaire en revanche donna accĂšs Ă des gels supramolĂ©culaires, Ă©voluant vers un Ă©tat liquide lors de la contraction des chaines polymĂšres. Finalement, lâinclusion de daisy chains dans un rĂ©seau polymĂšre 3D a donnĂ© accĂšs Ă un gel chimique. Ce matĂ©riau a pu ĂȘtre contractĂ© et Ă©tendu Ă lâĂ©chelle macroscopique grĂące Ă lâaction combinĂ©e des machines molĂ©culaires le constituant.Le quatriĂšme chapitre est dĂ©diĂ© Ă lâamĂ©lioration dâun gel contractile basĂ© sur lâutilisation de moteurs molĂ©culaires rotatif comme noeud de rĂ©ticulation dâun rĂ©seau polymĂšre. Une unitĂ© modulatrice, capable dâĂȘtre commutĂ© entre un Ă©tat âouvertâ et âfermĂ©â, a Ă©tĂ© introduite dans le rĂ©seau aux cĂŽtĂ©s du moteur. Le modulateur dans son Ă©tat âfermĂ©â permet aux moteurs molĂ©culaires de contracter efficacement le rĂ©seau, tandis que dans son Ă©tat ouvert il permet aux chaines de se dĂ©rouler alors que le moteur ne tourne pas, ce qui provoque lâextension du rĂ©seau qui retourne Ă sa taille initiale. En rĂ©sumĂ©, le travail dĂ©crit dans ce manuscrit illustre que des machines molĂ©culaires soigneusement conçue peuvent ĂȘtre introduites dans des rĂ©seaux polymĂšres, fournissant des matĂ©riaux dont les propriĂ©tĂ©s macroscopiques sont affectĂ©es par les mouvements nanoscopiques de ses constituants. Ces rĂ©sultats fournissent des pistes et une base fondamentale pour lâĂ©laboration dâune nouvelle classe de matĂ©riaux contractiles basĂ©s sur des machines molĂ©culaires
Amplification macroscopique de mouvements nanométriques induits par des machines moléculaires
Ces vingt derniĂšres annĂ©es, le domaine du design et de la synthĂšse de machines molĂ©culaires complexes a fait dâĂ©normes progrĂšs,souvent inspirĂ© par la beautĂ© de la machinerie prĂ©sente dans les systĂšmes vivants. Cependant, lâamplification des mouvements dâun grand nombre de machines molĂ©culaires Ă des Ă©chelles de tailles largement supĂ©rieures Ă leurs dimensions restent un dĂ©fi thĂ©orique et expĂ©rimental ambitieux et ardu. Ce travail dĂ©crit comment lâorganisation de machines et moteurs molĂ©culaires dans des rĂ©seaux polymĂšres supramolĂ©culaires ou covalents permet de synthĂ©tiser des matĂ©riaux dans lesquels leurs mouvements individuels nanomĂ©triques sont amplifiĂ©s jusquâĂ lâĂ©chelle macroscopique. Les trois premiers chapitres dĂ©crivent lâutilisation dâune architecture de type [c2]daisy chains, une molĂ©cule capable dâeffectuer des contraction/extensions similaires aux mouvements des sarcomĂšres prĂ©sents dans les muscles, dans des rĂ©seaux polymĂšres supramolĂ©culaires et covalents. Leur introduction dans des polymĂšres supramolĂ©culaires Ă liaisons hydrogĂšne basĂ©es sur le motif de reconnaissance uracil:2,6-diacetylaminopyridine associĂ© Ă des interactions latĂ©rales tel que les interactions Ï rĂ©sulta en la formation de fibre supramolĂ©culaires contractiles dont la taille et la morphologie a pu ĂȘtre commutĂ© entre deux Ă©tats Ă©tendus et contractĂ©s. Lâincorporation de motifs urĂ©idopyrimidinone comme connecteur supramolĂ©culaire en revanche donna accĂšs Ă des gels supramolĂ©culaires, Ă©voluant vers un Ă©tat liquide lors de la contraction des chaines polymĂšres. Finalement, lâinclusion de daisy chains dans un rĂ©seau polymĂšre 3D a donnĂ© accĂšs Ă un gel chimique. Ce matĂ©riau a pu ĂȘtre contractĂ© et Ă©tendu Ă lâĂ©chelle macroscopique grĂące Ă lâaction combinĂ©e des machines molĂ©culaires le constituant.Le quatriĂšme chapitre est dĂ©diĂ© Ă lâamĂ©lioration dâun gel contractile basĂ© sur lâutilisation de moteurs molĂ©culaires rotatif comme noeud de rĂ©ticulation dâun rĂ©seau polymĂšre. Une unitĂ© modulatrice, capable dâĂȘtre commutĂ© entre un Ă©tat âouvertâ et âfermĂ©â, a Ă©tĂ© introduite dans le rĂ©seau aux cĂŽtĂ©s du moteur. Le modulateur dans son Ă©tat âfermĂ©â permet aux moteurs molĂ©culaires de contracter efficacement le rĂ©seau, tandis que dans son Ă©tat ouvert il permet aux chaines de se dĂ©rouler alors que le moteur ne tourne pas, ce qui provoque lâextension du rĂ©seau qui retourne Ă sa taille initiale. En rĂ©sumĂ©, le travail dĂ©crit dans ce manuscrit illustre que des machines molĂ©culaires soigneusement conçue peuvent ĂȘtre introduites dans des rĂ©seaux polymĂšres, fournissant des matĂ©riaux dont les propriĂ©tĂ©s macroscopiques sont affectĂ©es par les mouvements nanoscopiques de ses constituants. Ces rĂ©sultats fournissent des pistes et une base fondamentale pour lâĂ©laboration dâune nouvelle classe de matĂ©riaux contractiles basĂ©s sur des machines molĂ©culaires.The last twenty years have seen tremendous progresses in the design and synthesis of complex molecular machines, often inspired by the beauty of the machinery found in biological systems. However, amplification of the molecular machines motion over several orders of magnitude above their typical length scale is still an ambitious challenge. This work describes how self-organization of molecular machines or motors allows for the synthesis of materials translating the motions of their components into a macroscopic response. The three first chapters describe the use of a [c2]daisy chains architecture, a molecule able to perform contraction/extension motions similarly to the sarcomere units of muscles, into systems such as supramolecular polymers and covalent networks. Their inclusion into hydrogen bonding supramolecular polymers based on the uracil:2,6-diacetylaminopyridine recognition motifs combined with lateral interactions such as Ï-stacking provided micrometric muscle-like fibers contracting and extending upon deprotonation and protonation.The incorporation of ureidopyrimidone moieties as supramolecular connectors yielded highly organized gels, which evolved to a liquidstate upon contraction of the polymer chains. Finally, covalent poly[c2]daisy chains were synthesized and investigated, notably the formation of a 3D network swelling into a gel. This material could contract and extend at the macroscopic scale upon contraction and extension of the molecular machines used as monomers. Finally, a fourth chapter is dedicated to the improvement of contractile chemical gels made by using a molecular motor as reticulating nodes. A modulating unit, able to be switched between a âclosedâ and an âopenedâ state, was introduced into the polymer network along with the motor. The locked structure in the âclosedâ state allowed contraction of the gel upon rotation of the molecular motors, while the âopenedâ state allowed unwinding of the entangled polymer chains and extension of the gel when the motor is off. Overall, the work presented in this manuscript demonstrates that carefully designed molecular machines can be incorporated into large supramolecular or covalent assemblies, providing materials which collective motions alter their macroscopic properties. These results provide valuable insights for the elaboration of a new class of muscle-like materials based on molecular machines
Photo-excitation et structure magnétique photo-induite dans les analogues photo-magnétiques du bleu de Prusse
PARIS-BIUSJ-ThĂšses (751052125) / SudocCentre Technique Livre Ens. Sup. (774682301) / SudocPARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF
- âŠ