Redox and ion-exchange properties in surface-tethered DNA-conducting polymers

A poly(cyclopentadithiophene) matrix modified by DNA covalently fixed to the surface has been designed to study the redox and ion-exchange properties in surface-tethered DNA-conducting polymers. Voltammetric investigations show an improvement in conductivity, originating from DNA modification, probably due to changes in charged-density and size of dopant species. Cyclic voltammetry with concomitant QCM measurements indicate that the mass changes are consistent with an ejection of Na+ cations associated to the anionic phosphate groups, attesting a DNA contribution to the p-doping process. So, in contrast to the classic doping patterns, the p-doping process of surface-tethered DNA-copolymer exhibits a cation-controlled transport mechanism. Impedimetric investigations indicate that for long enough DNA target sequence, nucleic acid preserves certain flexibility and is involved in the p-doping process through a diffusion-like motion. These results give new opportunities for genesensors development and for a better understanding of bioactive conducting surfaces

Hybridization-induced interfacial changes detected by non-Faradaic impedimetric measurements compared to Faradaic approach

A biosensor for direct label-free DNA detection based on a polythiophene matrix is investigated by electrochemical impedance spectroscopy (EIS). Impedimetric experiments are performed with and without redox probe in solution. The non-Faradaic impedance measurements reveal two relaxation processes located at 50 Hz and 5 kHz, respectively. The first relaxation process, located at low frequencies, allows to detect biorecognition events by measuring the phase angle decrease, in accordance with a hindrance of the polaronic conduction. The second relaxation process, located at 5 kHz and originating from DNA modification, seems to increase with the length of the target sequence. These results suggest that this loaded support provides a platform for impedimetric detection of hybridization at high frequencies, leading to less time-consuming detection procedure. For a better understanding, results obtained in non-Faradaic mode are compared with Faradaic approach

Jung and Deleuze: Enchanted Openings to the Other: A Philosophical Contribution

This paper draws from resources in the work of Deleuze to critically examine the notion of organicism and holistic relations that appear in historical forerunners that Jung identifies in his work on synchronicity. I interpret evidence in Jung's comments on synchronicity that resonate with Deleuze's interpretation of repetition and time and which challenge any straightforward foundationalist critique of Jung's thought. A contention of the paper is that Jung and Deleuze envisage enchanted openings onto relations which are not constrained by the presupposition of a bounded whole, whether at the level of the macrocosm or the microcosm. Openings to these relations entail the potential for experimental transformation beyond sedentary habits of thought which are blocked by a disenchanting ‘image of thought’ that stands in need of critique. Other examples of enchanted openings in Jung's work are signposted in an effort to counter their marginalisation in some post-Jungian critiques and to signal their potential value from a Deleuzian perspective

Adaptive responses of animals to climate change are most likely insufficient

Biological responses to climate change have been widely documented across taxa and regions, but it remains unclear whether species are maintaining a good match between phenotype and environment, i.e. whether observed trait changes are adaptive. Here we reviewed 10,090 abstracts and extracted data from 71 studies reported in 58 relevant publications, to assess quantitatively whether phenotypic trait changes associated with climate change are adaptive in animals. A meta-analysis focussing on birds, the taxon best represented in our dataset, suggests that global warming has not systematically affected morphological traits, but has advanced phenological traits. We demonstrate that these advances are adaptive for some species, but imperfect as evidenced by the observed consistent selection for earlier timing. Application of a theoretical model indicates that the evolutionary load imposed by incomplete adaptive responses to ongoing climate change may already be threatening the persistence of species

Kinetic analysis of the interaction of Mos1 transposase with its inverted terminal repeats reveals new insight into the protein-DNA complex assembly.

International audienceTransposases are specific DNA-binding proteins that promote the mobility of discrete DNA segments. We used a combination of physicochemical approaches to describe the association of MOS1 (an eukaryotic transposase) with its specific target DNA, an event corresponding to the first steps of the transposition cycle. Because the kinetic constants of the reaction are still unknown, we aimed to determine them by using quartz crystal microbalance on two sources of recombinant MOS1: one produced in insect cells and the other produced in bacteria. The prokaryotic-expressed MOS1 showed no cooperativity and displayed a Kd of about 300 nM. In contrast, the eukaryotic-expressed MOS1 generated a cooperative system, with a lower Kd (∼ 2 nm). The origins of these differences were investigated by IR spectroscopy and AFM imaging. Both support the conclusion that prokaryotic- and eukaryotic-expressed MOS1 are not similarly folded, thereby resulting in differences in the early steps of transposition

A 60 GHz UWB impulse radio transmitter with integrated antenna in CMOS 65nm SOI technology

This work describes an UWB impulse transmitter with integrated antenna in the 60 GHz band implemented in CMOS65nm SOI technology. The transmitter aims low-power short-range high data-rate communication systems for fast-downloading applications. It consists of an oscillator that is switched on-and-off by the digital data to be transmitted and a medium power amplifier. The transmitter is fabricated on two chips: one for direct on-chip measurements and another one implementing an integrated antenna. The transmitter measurements are performed on-chip and in free space in both continuous wave and impulse operating modes. The circuit achieves an equivalent isotropic radiated power of 2 dBm at 56 GHz and a maximum measured data rate of 2.222 Gbit/sec. The overall power consumption is 28 mW under 1.2 V voltage supply

Cyclodextrins as templates for the presentation of protease inhibitors

Schaschke N, Musiol HJ, AssfalgMachleidt I, Machleidt W, RudolphBohner S, Moroder L. Cyclodextrins as templates for the presentation of protease inhibitors. FEBS LETTERS. 1996;391(3):297-301

Molecular markers of dietary essential amino-acid deficiency

Molecular markers of dietary essential amino-acid deficiency. Nutrition 201