The Néel IRAM KID Arrays (NIKA)

We are developing an instrument based on Kinetic Inductance Detectors (KID) known as the Néel IRAM KID Array (NIKA). Leveraging the experience gained from the first generation NIKA in 2009, an improved, dual-band (150?GHz and 240?GHz) instrument has been designed and tested at the Institut of RadioAstronomie Millimetrique (IRAM) 30-meter telescope in October 2010. The performances, in terms of sensitivity on-the-sky at 150?GHz, are already comparable to existing state-of-the-art bolometer-based instruments. NIKA represents thus the first real proof that KID are a viable technology for ground-based Astronomy. We will describe the instrument, the most recent results and the future plans for building a large resident mm-wave camera.     

Prevention of hypothermia by cutaneous warming with new electric blankets during abdominal surgery

We have evaluated the efficacy of new electric warming blankets, which meet the requirements of the international standard for perioperative electrical and thermal safety, in preventing intraoperative hypothermia. We studied 18 patients undergoing abdominal surgery, allocated to one of two groups: in the control group, there was no prevention of intraoperative hypothermia (n = 8) and in the electric blanket group, two electric blankets covered the legs and upper body (n = 10). Anaesthesia duration was similar in the two groups (mean 201 (SEM 11) min), as was ambient temperature (20.5 (0.1) degrees C). Core temperature decreased during operation by 1.5 (0.1) degrees C in the control group, but only by 0.3 (0.2) degree C in the electric blanket group (P < 0.01). Five patients shivered in the control group compared with one in the electric blanket group (P < 0.05). We conclude that cutaneous warming with electric blankets was an effective means of preventing intraoperative hypothermia during prolonged abdominal surgery.     

Inhibition of lymphocyte proliferation by factor(s) produced by Schistosoma mansoni

Normal spleen cells of CBA mice or Fischer rats were cultured with mitogens or allogeneic cells, together with various substances of Schistosoma mansoni origin, and thymidine uptake was measured. The proliferation (DNA synthesis) of normal lymphocytes was inhibited by the incubation product of the parasite as well as by cell-free supernatant of schistosome culture. Inhibition was obtained only when active materials were added at the beginning of the culture. Both T and B cell proliferation were inhibited. The inhibitory activity found in cell-free supernatant suggested the release by the parasite of some factor(s) interfering with lymphocyte proliferation. Moreover, serum from rats infected by S. mansoni inhibited lymphocyte proliferation also. The inhibitor(s) appeared heat resistant, dialyzable and of low molecular weight (500-1000). Incubation of normal spleen cells with S. mansoni inhibitor(s) did not enhance the release of nonspecific suppressor cell factor. The inhibition of product(s) released by the parasite could explain part of the immunosuppression status found in schistosomiasis.     

Volatile tritiated organic acids in stack effluents and in air surrounding contaminated materials

A small fraction of the tritium released into the atmosphere from tritium-handling or solid waste storage facilities was shown to be in the form of volatile organic acids. The same compounds were also found, but at a much higher proportion, in the tritium evolved at room temperature from highly contaminated materials placed under air atmospheres. This might be due to the oxidation and labeling of hydrocarbon(s) by mechanisms that are presumably of a radiolytic nature. The new forms could have an impact on operational requirements and waste management strategies within a tritium facility and a fusion reactor hall. Further data are needed to assess the related doses.     

Mechanical Characterization of Si–C(O) Fiber/SiC (CVI) Matrix Composites witrTa BN–Interphase

The mechanical behavior of three CVT-processed 2D woven SiC/BN/SiC composite materials with different initial BN interphase thicknesses has been investigated by means of tensile and impact tests. The results have established the efficiency of a BN interphase in promoting a nonlinear/non–catastrophic tensile behavior and high impact resistance. The effect of the initial BN interphase thickness on the resulting mechanical behavior has also been demonstrated. Characterization of the fiber/matrix interfacial zones by AES and TEM has revealed the presence of a SiO₂/C double layer at the BN/fiber interface, which might result from a decomposition undergone by the Si–C(O) Nicalon fiber during processing. It has been suggested that the influence of the initial BN interphase thickness on the mechanical properties of the composites results from both changes occurring in the composition and morphology of the interfacial zones and modifications of the interfacial forces due to accommodation of the radial residual clamping stress.     

A 5.4 mW/0.07 mm$^{2}$ 2.4 GHz Front-End Receiver in 90 nm CMOS for IEEE 802.15.4 WPAN Standard

An integrated 2.4 GHz CMOS receiver front-end according to the IEEE 802.15.4 standard is presented in this paper. It integrates the overall RF part, from the balun up to the first stage of the channel filter, as well as the cells for the LO signal conditioning. The proposed architecture is based on a 6 MHz low-IF topology, which uses an inductorless LNA and a new clocking scheme for driving a passive mixer. When integrated in a 90 nm CMOS technology, the receiver front-end exhibits an area of only 0.07 mm², or 0.23 mm² when including an input integrated balun. The overall chip consumes 4 mA from a single 1.35 V supply voltage and it achieves a 35 dB conversion gain from input power in dBm to output voltage in dBvpk, a 7.5 dB NF value, -10 dBm of IIP3 and more than 32 dB of image rejection.     

A closed cycle He-He dilution refrigerator insensitive to gravity

The cooling power and the lifetime of an open cycle dilution refrigerator as developed for the Planck mission (100 nW at 100 mK during 30 months) are limited by the quantity of the helium isotopes carried on the satellite at launch, because the helium mixture obtained after the dilution process is rejected into space. Future space missions require to increase the cooling power and lifetime significantly (1 μW at 50 mK during 5 years).Therefore we are extending the open cycle dilution refrigerator with a helium isotope separator operating at 1 K to close the cycle. A first prototype to demonstrate the principle of the closed cycle dilution refrigerator has been tested and a cooling power of 1 μW at temperatures below 60 mK has been obtained. We present the apparatus and the experimental results and give some elements for its integration in a complete cooling chain. The advantages (continuous operation, absence of magnetic field, less weight) of a closed cycle dilution refrigerator with respect to an adiabatic demagnetization refrigerator are also discussed.     

Synthesis of ferroquine enantiomers: first investigation of effects of metallocenic chirality upon antimalarial activity and cytotoxicity

Ferroquine (FQ) is a new antimalarial agent with a high blood schizotoncidal activity. Previous studies on this compound were done with racemate mixtures. As FQ possesses planar chirality, pure enantiomers were obtained by enzymatic resolution in order to compare their antimalarial activities and cytotoxicities. (+)-FQ and (-)-FQ were equally active in vitro, at nanomolar concentrations. Both enantiomers were slightly less active than the racemate in vivo; cytotoxicities were similar. Actually, the racemate represents the optimal formulation. To the best of our knowledge, this is the first investigation of biological activities of compounds with metallocenic chirality.