Autonomous microfluidic multi-channel chip for real-time PCR with integrated liquid handling

We report on a novel, polymer-based, multi-channel device for polymerase chain reaction that combines, for the first time, rapid sample processing in less than 5min with high throughput at low costs. This is achieved by sample shuttling, during which submicroliter sample plugs (∼100nl) are oscillated rapidly over three constant-temperature zones by pneumatic actuation with integrated system. The accuracy and the speed of the liquid handling have been significantly increased, while the design of the device can be kept very simple and allows for mass production using conventional low-cost polymer fabrication processes. Massive parallelization can lead to a throughput up to 100 samples in 10min including the preparation time. The amplification can be optically monitored by means of online fluorescence detection. Successful real-time PCR and the determination of the threshold cycle, C t, using the developed device were demonstrated with plasmid DNA in a fluorescent real-time forma

Fünf Jahre Bachelor FH in der Schweiz

Copyright ©Swiss Chemical Society: CHIMIA, 64(7/8), 617-620, 2010, https://doi.org/10.2533/chimia.2010.617Berufsbefähigung und Praxisorientierung, das sind die Merkmale der Chemiker und Chemikerinnen, die an den vier Fachhochschulen in der Schweiz zu Bachelors of Science ausgebildet werden. Die Ausbildung zum Chemiker ist an den Hochschulen unterschiedlich ausgeprägt und eingebettet. Gemeinsam ist den Programmen die Vermittlung einer soliden theoretischen und praktischen Ausbildung, die auf eine gute Arbeitsmarktfähigkeit der Studierenden abzielt. Die Leichtigkeit, mit der die Absolvierenden Stellen finden, weist darauf hin, dass die erworbenen Kompetenzen von der Industrie nachgefragt werden

Electrochemical comparison of IrO2 prepared by anodic oxidation of pure iridium and IrO2 prepared by thermal decomposition of H2IrCl6 precursor solution

Surface redox activities, oxygen evolution reaction (OER), oxidation of formic acid (FA), and anodic stability were investigated and compared for IrO2 electrodes prepared by two techniques: the thermal decomposition of H2IrCl6 precursor (TDIROF) and the anodic oxidation of metallic iridium (AIROF). Surface redox activities involved on the AIROF were found to be much faster than those involved on the TDIROF. Concerning the oxygen evolution reaction, both films show a similar mechanism and specific electrocatalytic activities. The situation seems to be different for FA oxidation. In fact, on TDIROF, the oxidation of FA and the OER compete involving the same surface redox couple Ir(VI)/Ir(IV) contrary to FA oxidation on AIROF, where the Ir(V)/Ir(IV) surface redox couple is involved. Finally, electrode stability measurements have shown that contrary to TDIROF, which are very stable under anodic polarization, the AIROF are rapidly corroded under anodic treatment. This corrosion is enhanced even further in the presence of formic aci

PTH and 1.25 vitamin D response to a low-calcium diet is associated with bone mineral density in renal stone formers

Background. Renal calcium stones and hypercalciuria are associated with a reduced bone mineral density (BMD). Therefore, the effect of changes in calcium homeostasis is of interest for both stones and bones. We hypothesized that the response of calciuria, parathyroid hormone (PTH) and 1.25 vitamin D to changes in dietary calcium might be related to BMD. Methods. A single-centre prospective interventional study of 94 hyper- and non-hypercalciuric calcium stone formers consecutively retrieved from our stone clinic. The patients were investigated on a free-choice diet, a low-calcium diet, while fasting and after an oral calcium load. Patient groups were defined according to lumbar BMD (z-score) obtained by dual X-ray absorptiometry (group 1: z-score 0.5, n = 28). The effect of the dietary interventions on calciuria, 1.25 vitamin D and PTH in relation to BMD was measured. Results. An inverse relationship between BMD and calciuria was observed on all four calcium intakes (P = 0.009). On a free-choice diet, 1.25 vitamin D and PTH levels were identical in the three patient groups. However, the relative responses of 1.25 vitamin D and PTH to the low-calcium diet were opposite in the three groups with the highest increase of 1.25 vitamin D in group 1 and the lowest in group 3, whereas PTH increase was most pronounced in group 3 and least in group 1. Conclusion. Calcium stone formers with a low lumbar BMD exhibit a blunted response of PTH release and an apparently overshooting production of 1.25 vitamin D following a low-calcium die

LOWER BODY KINEMATICS AND MUSCLE ACTIVITY DURING EXERCICES IN 3D MOTORIZED ROTATING PLATFORM. IN-VIVO STUDY AND MODEL

The purpose of this study was to characterize muscle solicitations implied by the movement of a motorized rotating platform (MRP). Subjects performed five classical exercises on a MRP as part of lower limbs rehabilitation programs. EMG signals were recorded to quantify level and duration of activation of seven lower limbs muscles. Subject-specific musculoskeletal models were built and animated from kinematic recordings to estimate muscle lengths evolution. Results show that unipodal stance exercise was more demanding compared to bipodal ones. The characterization of solicitations imposed by MRP exercises could be useful for physiotherapists in order to help them to better select and configure exercises regarding to subject specificities, pathology and rehabilitation evolution

Packaging 3D pour MOSFET en carbure de silicium

International audienceLe développement d'un packaging dédié aux transistors à grand gap (SiC et GaN) est un point clef pour tirer pleinement profit de leurs caractéristiques remarquables. Un packaging en trois dimensions, basé sur un procédé de fabrication des circuits imprimés, est présenté dans cet article. Une cellule de commutation à base de MOSFET SiC est développé avec une inductance parasite de seulement 0.25nH. De plus, les interconnexions électriques du module sont réalisées sans brasures ni fil de bonding. Un module 3D est fabriqué puis validé expérimentalement. Des caractérisations électriques statiques et dynamiques sont réalisées et valident électriquement le concept « Power Chip On Chip » avec un procédé de fabrication de circuit imprimé

Gain-of-function haplotype in the epithelial calcium channel TRPV6 is a risk factor for renal calcium stone formation

The rate-limiting step of dietary calcium absorption in the intestine requires the brush border calcium entry channel TRPV6. The TRPV6 gene was completely sequenced in 170 renal calcium stone patients. The frequency of an ancestral TRPV6 haplotype consisting of three non-synonymous polymorphisms (C157R, M378V, M681T) was significantly higher (P = 0.039) in calcium stone formers (8.4%; derived = 502, ancestral = 46) compared to non-stone-forming individuals (5.4%; derived = 645, ancestral = 37). Mineral metabolism was investigated on four different calcium regimens: (i) free-choice diet, (ii) low calcium diet, (iii) fasting and (iv) after a 1 g oral calcium load. When patients homozygous for the derived haplotype were compared with heterozygous patients, no differences were found with respect to the plasma concentrations of 1,25-vitamin D, PTH and calcium, and the urinary excretion of calcium. In one stone-forming patient, the ancestral haplotype was found to be homozygous. This patient had absorptive hypercalciuria. We therefore expressed the ancestral protein (157R+378V+681T) in Xenopus oocytes and found a significantly enhanced calcium permeability when tested by a 45Ca2+ uptake assay (7.11 ± 1.93 versus 3.61 ± 1.01 pmol/min/oocyte for ancestral versus derived haplotype, P < 0.01). These results suggest that the ancestral gain-of-function haplotype in TRPV6 plays a role in calcium stone formation in certain forms of absorptive hypercalciuri

Multisite monitoring of choline using biosensor microprobe arrays in combination with CMOS circuitry

A miniature device enabling parallel in vivo detection of the neurotransmitter choline in multiple brain regions of freely behaving rodents is presented. This is achieved by combining a biosensor microprobe array with a custom-developed CMOS chip. Each silicon microprobe comprises multiple platinum electrodes that are coated with an enzymatic membrane and a permselective layer for selective detection of choline. The biosensors, based on the principle of amperometric detection, exhibit a sensitivity of 157±35 µA mM-1 cm-2, a limit of detection of below 1 µM, and a response time in the range of 1 s. With on-chip digitalization and multiplexing, parallel recordings can be performed at a high signal-to-noise ratio with minimal space requirements and with substantial reduction of external signal interference. The layout of the integrated circuitry allows for versatile configuration of the current range and can, therefore, also be used for functionalization of the electrodes before use. The result is a compact, highly integrated system, very convenient for on-site measurement

Understanding the spatial organization of agricultural co-operative groups (In French)

The processes of localization/delocalization of activities attest that space is important in firm’s strategies. Merger and acquisition contributes too modify the spatial organization of firms. This paper aims at analyzing the spatial organization at the level of groups of firms. The conceptual framework combines an analysis in terms of proximity and theories of the firm. We study the co-operative agricultural groups, which are relevant to question the territorial anchoring of the firm. Spatial indicators are proposed and mobilized at different levels of organization of the groups. Results show the importance of territorial anchoring in the strategies of co-operatives heads of the group. However, the development of big co-operative groups could lead to changes in the spatial logics facing a context of globalization.NAAgricultural cooperatives, Mutualist control, Territorial anchoring