265 research outputs found

    A course on Climate Change and Sustainable Building Design

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    We present an intermediate-level course on sustainable physics, which combines lectures and student projects. Sustainable physics concepts are progressively introduced through both a global and a specialized perspective: climate change and building design. The lectures and hands-on activities on both topics show how they share common concepts and provide complementary points of view. Climate change mitigation and adaptation are touched on via student group projects, where they are asked to tackle a specific question of their choosing via reviews of the literature, modeling or experiments.Comment: 11 pages + Supp Matt 20 page

    BRCA1 Expression is an Important Biomarker for Chemosensitivity: Suppression of BRCA1 Increases the Apoptosis via Up-regulation of p53 and p21 During Cisplatin Treatment in Ovarian Cancer Cells

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    BRCA1 is a tumor suppressor which plays a crucial role in the repair of DNA double-strand breaks, and its abnormality is responsible for hereditary ovarian cancer syndrome. It has recently been reported that reduced expression of BRCA1 is also common in sporadic ovarian carcinoma via its promoter hypermethylation, and that ovarian carcinoma patients negative for BRCA1 expression showed favorable prognosis. To address if BRCA1 expression plays a role in the chemotherapeutic response, we analyzed the effect of BRCA1 suppression on the sensitivity to cisplatin and paclitaxel in ovarian cancer cells. Specific siRNA for BRCA1 gene was transfected into 3 ovarian cancer cell lines with various p53 status. Reduced expression of BRCA1 by transfection of BRCA1-siRNA resulted in a 5.3-fold increase in sensitivity to cisplatin in p53-wild A2780 cells, but not in p53-mutated A2780/CDDP and p53-deleted SKOV3 cells. Regarding the sensitivity to paclitaxel, BRCA1 suppression caused no significant changes in all the 3 cell lines. For ionizing radiation sensitivity, BRCA1 suppression also showed a significant higher sensitivity in A2780 cells. Growth curve and cell cycle analyses showed no significant differences between BRCA1-siRNA-transfected A2780 cells and control cells. However, cisplatin treatment under suppression of BRCA1 showed a significantly increased apoptosis along with up-regulation of p53 and p21 in A2780 cells. Accordingly, reduced expression of BRCA1 enhances the cisplatin sensitivity and apoptosis via up-regulation of p53 and p21, but does not affect the paclitaxel sensitivity. Expression of BRCA1 might be an important biomarker for cisplatin resistance in ovarian carcinoma

    Role of Plasma Protein and Low-Molecular Weight Substances in the Change of Hydroxyl Radical Scavenging Activity in Hemodialysis Patients

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    While it is well known that hemodialysis (HD) patients with end stage renal failure are exposed to high oxidative stress, there is not a general opinion regarding whether antioxidant activity is high or low in these patients. We evaluated the variation of plasma hydroxyl radical scavenging activity (p-HRSA) by a single-session of HD in 69 patients by using a new system, reactive flow-injection electron spin resonance. And then comparing p-HRSA with their biochemical parameters, we tried to elucidate what components affected p-HRSA in the HD patients. The average of p-HRSA significantly increased after HD and the variation of p-HRSA by HD was correlated with that of plasma total protein (TP). In 5 patients however, their p-HRSA decreased after HD, in spite of increasing TP. In pre-HD, the p-HRSA values and hydroxyl radical scavenging activity of low-molecular weight fraction of plasma were significantly higher in these 5 patients than in patients whose p-HRSA increased after HD. These 5 patients were in an inflammatory state. These findings suggest that p-HRSA is mainly affected by TP, but caution should be exercised in patients who have high p-HRSA before HD and whose p-HRSA does not increase after HD

    Transitions de phase quantiques dans les systèmes désordonnés de basse dimension

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    La supraconductivité s établit par une organisation collective des électrons, décrite dans le cadre de la théorie BCS par une même fonction d onde macroscopique. En présence de fort désordre, la situation est plus complexe : le désordre induit un renforcement des interactions coulombiennes et une localisation des électrons, s opposant à l établissement de la supraconductivité. Pour un désordre critique, la supraconductivité est détruite et le système devient métallique ou isolant. A 2D, en l absence de fortes interactions coulombiennes, la théorie de la localisation d Anderson interdit l existence d un état métallique : le désordre induit une Transition Supraconducteur-Isolant (TSI). Durant cette thèse, nous avons étudié les propriétés de transport à très basse température de films minces amorphes de NbxSi1-x. Nous avons effectué des mesures de résistance à basse fréquence à travers la TSI et initié des mesures d impédance complexe à hautes fréquences (quelques GHz), afin de sonder la dynamique du système à travers la TSI. L étude du transport statique s est focalisée sur l évolution du NbxSi1-x avec le recuit. Ce paramètre induit une variation progressive du désordre microscopique de notre système, ce qui nous a permis d étudier finement la TSI. Nous avons ainsi mis en évidence deux états dissipatifs, séparant les états supraconducteurs et isolants, et non-prédits par les théories actuelles. Par ailleurs, nous avons mis au point un dispositif de mesure de réflectométrie micro-onde large bande. Nous avons en particulier développé une méthode de calibration, utilisant non pas la mesure de références externes comme il est usuel, mais un ensemble d hypothèses sur la réponse électrodynamique des échantillons. Cette méthode permet de s affranchir de l environnement micro-onde de ceux-ci. Les résultats obtenus permettent une première validation de cette démarche et constituent donc un premier pas vers la détermination de la réponse dynamique absolue du système à travers la TSI.Superconductivity is established by the collective organization of electrons, then described within the BCS theory through a single macroscopic wave function. In the presence of strong disorder, the situation becomes more complex: disorder enhances Coulomb interactions and induces the localization of electrons. These two phenomena act against superconductivity. For a critical disorder, the superconducting state is destroyed and the system becomes either metallic or insulating. In 2D, in the absence of strong Coulomb interactions, the theory of Anderson localization prevents the existence of a metallic state. Disorder thus induces a Superconductor-Insulator Transition (SIT). We have studied the transport properties of amorphous NbxSi1-x thin films at very low temperature. We have performed resistance measurements at low frequencies through the SIT and initiated measurements of the complex impedance at higher frequencies (a few GHz) in order to probe the dynamics of the system through this quantum phase transition. The study of the static properties of NbxSi1-x films have focused on the effect of annealing. This parameter induces a gradual variation of the microscopic disorder of this system, which allowed us a very fine tuning of the SIT. We have thus evidenced two dissipative states, non-predicted by the current theories of the SIT, which separate the superconducting and insulating ground states. In parallel, we have set up a broadband microwave reflectometry experiment. In particular, we have developed a calibration procedure based on hypotheses on the electrodynamic response of the samples and not on the measure of external references as it is usual. This method allows us to measure the sample s response independently from the experimental setup. The results we have obtained provide a first validation of this approach and therefore constitute a first step towards the determination of the absolute dynamical response of the system through the SIT.PARIS11-SCD-Bib. électronique (914719901) / SudocSudocFranceF

    Placental Mesenchymal Dysplasia: Chronological Observation of Placental Images during Gestation and Review of the Literature

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    Placental mesenchymal dysplasia (PMD) is characterized by multiple hypoechoic vesicles which are similar to molar changes in the placenta; however, the process of such morphological changes of PMD during pregnancy has not been fully understood. We performed a review of all PMD cases published in English and identified 49 articles including 110 cases. With regard to the gestational age at which the multicystic pattern was seen, approximately 70% of cases were diagnosed at 13-20 weeks of gestation. Another characteristic feature of PMD is varicose dilation of fetal chorionic vessels. As many as 90% of cases were diagnosed as placenta with dilated fetal chorionic vessels in the third trimester. We also report a case of PMD which was found at 10 weeks of gestation according to ultrasonic molar patterns. Serial observations of the placenta using ultrasound and magnetic resonance imaging revealed that multicystic lesions became smaller after 23 weeks. In contrast, dilated placental vessels on the fetal side became apparent at 38 weeks. The present review highlights that placental vesicular lesions of PMD may precede dilation of fetal chorionic vessels during pregnancy. It also indicates the potential of a gradual reduction in size of PMD's placental vesicular lesions by serial study of placental images.ArticleGYNECOLOGIC AND OBSTETRIC INVESTIGATION. 75(4):217-223 (2013)journal articl

    Rate of red blood cell destruction varies in different strains of mice infected with Plasmodium berghei-ANKA after chronic exposure

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    <p>Abstract</p> <p>Background</p> <p>Severe malaria anaemia in the semi-immune individuals in the holo-endemic area has been observed to occur at low parasite density with individual variation in the responses. Thus the following has been thought to be involved: auto-immune-mediated mechanisms of uninfected red blood cell destruction, and host genetic factors to explain the differences in individual responses under the same malaria transmission. In this study, the extent of red blood cell (RBC) destruction in different strains of semi-immune mice model at relatively low parasitaemia was studied.</p> <p>Methodology</p> <p>To generate semi-immunity, four strains of mice were taken through several cycles of infection and treatment. By means of immunofluorescent assay and ELISA, sera were screened for anti-erythrocyte auto-antibodies, and their relationship with haematological parameters and parasitaemia in the strains of semi-immune mice was investigated.</p> <p>Results</p> <p>Upon challenge with <it>Plasmodium berghei </it>ANKA after generating semi-immune status, different mean percentage haemoglobin (Hb) drop was observed in the mice strains (Balb/c = 47.1%; NZW = 30.05%; C57BL/6 = 28.44%; CBA = 25.1%), which occurred on different days for each strain (for Balb/c, mean period = 13.6 days; for C57BL/6, NZW, and CBA mean period = 10.6, 10.8, 10.9 days respectively). Binding of antibody to white ghost RBCs was observed in sera of the four strains of semi-immune mice by immunofluorescence. Mean percentage Hb drop per parasitaemia was highest in Balb/c (73.6), followed by C57BL/6 (8.6), CBA (6.9) and NZW (4.0), p = 0.0005. Consequently, auto-antibodies level to ghost RBC were correlated with degree of anaemia and were highest in Balb/c, when compared with the other strains, p < 0.001.</p> <p>Conclusion</p> <p>The results presented in this study seem to indicate that anti-RBC auto-antibodies may be involved in the destruction of uninfected RBC in semi-immune mice at relatively low parasite burden. Host genetic factors may also influence the outcome of auto-immune mediated destruction of RBC due to the variation in Hb loss per % parasitaemia and differences in antibody titer for each semi-immune mice strain. However, further studies at the molecular level ought to be carried out to confirm this.</p
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