Thermo-electric energy storage using co2 transcritical cycles and ground heat storage

Multi-megawatt thermo-electric energy storage based on thermodynamic cycles is a promising alternative to PSH (Pumped-Storage Hydroelectricity) and CAES (Compressed Air Energy Storage) systems. The size and cost of the heat storage are the main drawbacks of this technology but using the ground as a heat reservoir could be an interesting and cheap solution. In that context, the aim of this work is i) to assess the performance of a massive electricity storage concept based on CO2 transcritical cycles and ground heat exchangers, and ii) to carry out the preliminary design of the whole system. This later includes a heat pump transcritical cycle as the charging process and a transcritical Rankine cycle of 1 – 10 MWe as the discharging process. A steady-state thermodynamic model is realized and several options, including regenerative or multi-stage cycles, are investigated. In addition, a one-dimensional design model of the geothermal heat exchanger network is used to optimize the number of wells for the ground heat storage. The results show the strong dependency between the charging and discharging cycles, and how the use of regenerative heat exchangers and a two-phase expander (in the charging cycle) could increase the system efficiency and lower the investment cost.Papers presented to the 12th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Costa de Sol, Spain on 11-13 July 2016

Enhancement of flow boiling heat transfer in microchannels by nano- and micro-surface treatments

This work investigates the flow boiling heat transfer in microchannels with the aim of developing compact cooling systems which can be adapted to miniaturized power components. Nano and micro-surface treatments were used as innovative techniques to improve the heat transfer performance as well as to delay the intermittent dryout. It was observed that the micro-structured surfaces show significant enhancements (up to 85%) in heat transfer compared to the smooth surfaces. Especially, using the highly-wetted structured surface, the intermittent dryout is improved

Remote electrochemical modulation of pKa in a rotaxane by co-conformational allostery

Allosteric control, one of Nature’s most effective ways to regulate functions in biomolecular machinery, involves the transfer of information between distant sites. The mechanistic details of such a transfer are still object of intensive investigation and debate, and the idea that the intramolecular communication could be enabled by dynamic processes is gaining attention as a complement to traditional explanations. Mechanically interlocked molecules, owing to the particular kind of connection between their components and the resulting dynamic behavior, are attractive systems to investigate allosteric mechanisms and exploit them to develop functionalities with artificial species. We show that the pKa of an ammonium site located on the axle component of a [2]rotaxane can be reversibly modulated by changing the affinity of a remote recognition site for the interlocked crown ether ring through electrochemical stimulation. The use of a reversible ternary redox switch enables us to set the pKa to three different values, encompassing more than 7 units. Our results demonstrate that in the axle the two sites do not communicate, and that in the rotaxane the transfer of information between them is made possible by the shuttling of the ring, that is, by a dynamic intramolecular process. The investigated coupling of electron- and proton-transfer reactions is reminiscent of the operation of the protein complex I of the respiratory chain

Adaptable Overhanging Carboxylic Acid Porphyrins Towards Molecular Assemblies through Unusual Coordination Modes

International audienceA new family of strap porphyrins exhibiting out/in overhanging carboxylic acid stereoisomerism, has been synthesized and investigated for its coordination properties. Their 5,10 linkage allows a significant flexibility of the strap which exhibits various degrees of angulation relatively to the mean porphyrin plane, making the ligand adjustable to the metal it binds. Notably, in the case of Bi(III), a second sphere of coordination plays a crucial role for the side selective insertion of the large metal ion. As a result, inward and outward orientation of the overhanging carboxylic acid function can be tuned, which is of interest for supramolecular coordination assemblies

Inherently Chiral Calixarenes: Synthesis, Optical Resolution, Chiral Recognition and Asymmetric Catalysis

Inherently chiral calixarenes, whose chirality is based on the absence of a planar symmetry or an inversion center in the molecules as a whole through the asymmetric array of several achiral groups upon the three-dimensional calix-skeletons, are challenging and attractive chiral molecules, because of their potential in supramolecular chemistry. The synthesis and optical resolution of all varieties of inherently chiral calixarenes are systematically discussed and classified, and their applications in chiral recognition and asymmetric catalysis are thoroughly illustrated in this review

8p22 MTUS1 Gene Product ATIP3 Is a Novel Anti-Mitotic Protein Underexpressed in Invasive Breast Carcinoma of Poor Prognosis

BACKGROUND: Breast cancer is a heterogeneous disease that is not totally eradicated by current therapies. The classification of breast tumors into distinct molecular subtypes by gene profiling and immunodetection of surrogate markers has proven useful for tumor prognosis and prediction of effective targeted treatments. The challenge now is to identify molecular biomarkers that may be of functional relevance for personalized therapy of breast tumors with poor outcome that do not respond to available treatments. The Mitochondrial Tumor Suppressor (MTUS1) gene is an interesting candidate whose expression is reduced in colon, pancreas, ovary and oral cancers. The present study investigates the expression and functional effects of MTUS1 gene products in breast cancer. METHODS AND FINDINGS: By means of gene array analysis, real-time RT-PCR and immunohistochemistry, we show here that MTUS1/ATIP3 is significantly down-regulated in a series of 151 infiltrating breast cancer carcinomas as compared to normal breast tissue. Low levels of ATIP3 correlate with high grade of the tumor and the occurrence of distant metastasis. ATIP3 levels are also significantly reduced in triple negative (ER- PR- HER2-) breast carcinomas, a subgroup of highly proliferative tumors with poor outcome and no available targeted therapy. Functional studies indicate that silencing ATIP3 expression by siRNA increases breast cancer cell proliferation. Conversely, restoring endogenous levels of ATIP3 expression leads to reduced cancer cell proliferation, clonogenicity, anchorage-independent growth, and reduces the incidence and size of xenografts grown in vivo. We provide evidence that ATIP3 associates with the microtubule cytoskeleton and localizes at the centrosomes, mitotic spindle and intercellular bridge during cell division. Accordingly, live cell imaging indicates that ATIP3 expression alters the progression of cell division by promoting prolonged metaphase, thereby leading to a reduced number of cells ungergoing active mitosis. CONCLUSIONS: Our results identify for the first time ATIP3 as a novel microtubule-associated protein whose expression is significantly reduced in highly proliferative breast carcinomas of poor clinical outcome. ATIP3 re-expression limits tumor cell proliferation in vitro and in vivo, suggesting that this protein may represent a novel useful biomarker and an interesting candidate for future targeted therapies of aggressive breast cancer

Investigation expérimentale du comportement transitoire de machines frigorifiques : Cas des échangeurs à plaques et des échangeurs à tubes et calandre

The purpose of this work is to evaluate the transient behaviour of refrgerators during various operating transients. A experimental stydy is realized on two different machines : the first one is a 60 kW liquid chiller with shell-and-tubes heat exchangers. The second one is a 10 kW liquid chiller with plate heat exchangers. Both of the machines work with refrigerant R-407C. The study of chiller equipped with shell-and -tubes exchangers points out that the transcients are sensitive to the shut down period and to the static superheat of the themostatic expansion valve. Moreover the transcients due to any variations (start-up, power change, mass flow rate change) lead to a disturbed and violent transients in the lower pressure side. Finally, concerning the use of the refrigerant R407C, a important composition glide is observed during start-up and shutdown transcients. The study of the lower power chiller deals with the global behaviour in the first time. Then the plate evaporator is locally studied by measuring the wall temperature, the water temperature and the refrigerant temperature. The behaviour of this chiller is rather different than the first one. Superheat instabilities appear for a range of refrigerant mass flow rate of 195 kg/h to 205 kg/h. Moreover the fiow distributionat the inlet of the evaporator should influence the transient. Finally, the measured beat transfer coefficient of the refrigerant points out thatusual correlations underestimate strongly the heat transfer in the post-dryout zone. This result is explained by the liquid droplets in thevapour core, which increase the heat transfer.L'objectif de ce travail de thèse est la caractérisatiorn du comportement dymamique de machines frigorifiques lors des différentes phases transitoires intervenant durant leur utilisation. Une étude expérimentale a été réalisée sur deux machines : la première d'une puissance utile de 60 kW est dotée d'échangeurs à tubes et calandre ; la seconde, ayant une puissance utile de 10 kW, est équipée d'échangeurs àplaques à chevrons. Les deux installations utilisent le réfrigérant R-407C. L'étude du groupe froid de puissance moyenne équipé d'échangeurs à tubes et calandre a souligné la sensibilité du comportementtransitoire à la durée de l'arrêt avant le démarrage et à la valeur de la consigne de surchauffe imposée au détendeur thermostatique. De plus, il est apparu que la réponse transitoire à une sollicitation quelconque (démarrage, variation de puissance ou variation de débit de réfrigérant) entraîne un comportement transitoire plus marqué et perturbé dans la zone à basse pression. Enfin, concernant l'emploi du réfrigérant R-407C, un changement de composition significatif a été mesuré lors des phases de démarrage et d'arrêt de la machine.L'étude du groupe froid de petite puissance, dotée d'échangeurs à plaques, a d'abord été axée sur le comportement général del'instauration. Puis l'étude locale de l'évaporateur a été menée grâce à une instrumentation fine des canaux. Le comportement de ce groupe froid diffère fortement du premier étudié. Les instabilités de surchauffe apparaissent entre deux valeurs de débit, et un effet prépondérant de la distribution du fluide diphasique dans l'évaporateur influence le comportement transitoire. En outre, la mesure du coefficient d'échange local en évaporation indique que les corrélations usuelles sous estiment fortement les échanges thermiques, notamment dans la zone de post assèchement, à cause d'un effet de primage de liquide important

Admission directe des patients âgés de plus de 70 ans en services hospitaliers : évaluation de l'utilisation par les médecins généralistes d'une ligne téléphonique directe (l'outil Allo Gériatrie) pour l'hospitalisation des sujets âgés en MCO de Gériatrie

The French population is getting older, and the attendance of the emergency department by the elderly is becoming more important. Many patients are sent there to be hospitalized although it is not always indicated by the clinical context, because general practitioners have difficulty in sending their patients in direct hospitalization. In May 2017, the geriatric pole GeST14 within the Assistance Publique-Hôpitaux de Marseille set up a hotline called « Allo Gériatrie » which allows the general practitioners to contact a geriatrician directly.The main objective of this study is to assess the satisfaction of the general practitioners who used the hotline to have one of their patients hospitalized. The secondary objectives are to compare the characteristics of patients whether they were hospitalized from the emergency or directly from home, and to estimate the impact the hotline may have had on the number of elderly patients attending the emergency department of La Timone Hospital.A satisfaction survey consisting in a questionnaire was sent to the general practitioners who had used the hotline in the first 6 months to hospitalize patients aged 70 and more. A retrospective observational study was conducted to compare the patients aged 70 and more hospitalized from the emergency department or from home between May 3rd and November 3rd, 2017.Twenty-nine doctors (72.4%) answered the questionnaire, 66.7% were « very satisfied » and 28.6% were « rather satisfied » with the use of the hotline.Besides, 601 patients were included in the observational study: 55 in the group « Allo Gériatrie », 418 in the group « Emergency » and 128 in the group « Other ». Patients were 86 years old on average [IC 95%, 86.23-87.29; p = 0.146]. The clinical severity was comparable between the groups according to two criteria: the length of the stay, 13 days on average [IC 95%, 1.41-13.73; p = 0.651], and the cost of the stay, 5470 euros on average [IC 95%, 5301.646-5638.531; p = 0.693]. The diagnoses were significantly different between the groups (p < 0.05): the patients hospitalized from the emergency department seemed to have more infectious pathologies, strokes and other cardiovascular diseases, whereas those hospitalized from home seemed to have more dementia or onco-haematological pathologies decompensations. The patients hospitalized via the hotline tended to return home more often than the others (p = 0.069). Finally, we did not notice any decrease in the number of elderly people attending the emergency department of La Timone Hospital after the first 6 months the hotline had been set up.The geriatric hotline satisfies the general practitioners and helps improve the city-hospital link. The diagnoses differ from one patient to another whether they come from home or from the emergency department. Therefore, the development of geriatric hotlines for specific profiles of patients is justified.La population française vieillit, et la fréquentation des services d’urgences par les personnes âgées est de plus en plus importante. De nombreux patients y sont adressés en vue d’une hospitalisation, bien que cela ne soit pas toujours indiqué par le contexte clinique, car les médecins généralistes peinent à adresser leurs patients en hospitalisation directe. En mai 2017, le pôle de gériatrie GeST14 de l’Assistance Publique-Hôpitaux de Marseille a mis en place une ligne téléphonique nommée « Allo Gériatrie », qui permet aux médecins généralistes de contacter directement un médecin gériatre.L’objectif principal de l’étude est d’évaluer la satisfaction des médecins généralistes ayant fait hospitaliser un patient par le biais de cet outil. Les objectifs secondaires sont de comparer les caractéristiques des patients admis en entrée directe ou par les urgences, et d’évaluer l’impact qu’a eu la permanence téléphonique sur le nombre de passages de patients âgés aux urgences de l’hôpital La Timone.Une enquête de satisfaction composée d’un questionnaire a été adressée aux médecins traitants ayant fait hospitaliser un patient de plus de 70 ans par le biais de la ligne téléphonique dans les 6 premiers mois de sa mise en service. Une étude observationnelle rétrospective comparant les patients de plus de 70 ans hospitalisés entre le 3 mai et le 3 novembre 2017 depuis le SAU ou en entrée directe a été réalisée.Vingt-neuf médecins (72,4%) ont répondu au questionnaire, 66,7% se sont déclarés « très satisfaits » et 28,6% « plutôt satisfaits » de l’utilisation de la ligne téléphonique. Par ailleurs, 601 patients ont été inclus dans l’étude observationnelle : 55 dans le groupe « Allo Gériatrie », 418 dans le groupe « Urgences » et 128 dans le groupe « Autre ». Les patients étaient âgés en moyenne de 86 ans [IC 95%, 86.23-87.29 ; p = 0,146]. La sévérité clinique était comparable entre les groupes selon les critères de durée de séjour, en moyenne de 13 jours [IC 95%, 1.41-13.73 ; p = 0,651] et de valorisation du séjour, en moyenne de 5470 euros [IC 95%, 5301.646-5638.531 ; p = 0,693]. Les profils diagnostiques des patients étaient significativement différents (p < 0,05) : ceux admis depuis les urgences semblaient l’être plus pour des pathologies infectieuses, des AVC ou d’autres maladies cardiovasculaires, et ceux admis depuis le domicile plus pour des décompensations de démences ou de pathologies onco-hématologiques. Les patients hospitalisés via l’outil Allo Gériatrie avaient tendance à retourner plus souvent à leur lieu de vie antérieur que les autres (p = 0,069). Enfin, on ne notait pas de diminution du nombre de passages de patients âgés aux urgences de la Timone dans les 6 mois suivant la mise en place de la ligne téléphonique.La permanence téléphonique gériatrique satisfait aux attentes des médecins généralistes, et permet d’améliorer le lien ville-hôpital. Les profils diagnostiques des patients hospitalisés diffèrent selon leur provenance, et cela justifie le développement de permanences téléphoniques gériatriques pour des profils ciblés