Scanning thermal microscopy based on a quartz tuning fork and a micro-thermocouple in active mode (2ω method).

A novel probe for scanning thermal microscope using a micro-thermocouple probe placed on a Quartz Tuning Fork (QTF) is presented. Instead of using an external deflection with a cantilever beam for contact detection, an original combination of piezoelectric resonator and thermal probe is employed. Due to a non-contact photothermal excitation principle, the high quality factor of the QTF allows the probe-to-surface contact detection.

Development of a new generation of ammonia sensors on printed polymeric hotplates.

Conducting polyaniline-based chemiresistors on printed polymeric micro-hotplates were developed, showing sensitive and selective detection of ammonia vapor in air. The devices consist of a fully inkjet-printed silver heater and interdigitated electrodes on a polyethylene naphthalate substrate, separated by a thin dielectric film. The integrated heater allowed operation at elevated temperatures, enhancing the ammonia sensing performance.

Two omega method for active thermocouple microscopy.

We present a contribution to a new mode of scanning thermal microscopy (SThM) based on the use of thermoelectric junction operating in ac active mode. This is the first alternative to 3omega operating mode of a resistive SThM probe for measuring thermophysical parameters of materials at micro- and nanoscale. Whereas a current at omega frequency generates by Joule effect a 2omega thermal oscillation along the wires, the junction thermoelectric voltage can be measured by means of a differential bridge scheme associated to a lock-in amplifier.

Calcium signaling via phospholipase C is essential for proline accumulation upon ionic but not nonionic hyperosmotic stresses in Arabidopsis.

Proline (Pro) accumulation occurs in various plant organisms in response to environmental stresses. To identify the signaling components involved in the regulation of Pro metabolism upon water stress in Arabidopsis (Arabidopsis thaliana), a pharmacological approach was developed. The role of phosphoinositide-specific phospholipases C (PLCs) in Pro accumulation was assessed by the use of the aminosteroid U73122, a commonly employed specific inhibitor of receptor-mediated PLCs.

Transcriptional regulation of proline biosynthesis in Medicago truncatula reveals developmental and environmental specific features.

The model legume plant Medicago truncatula accumulates free proline in response to hyperosmotic stress as do many other organisms. In order to analyse the transcriptional regulation of proline biosynthesis in M. truncatula, three cDNAs encoding Delta(1)-pyrroline-5-carboxylate synthetase (P5CS1, P5CS2; EC not assigned) and ornithine delta-aminotransferase (OAT; EC 2.

Phospholipase D is a negative regulator of proline biosynthesis in Arabidopsis thaliana.

Accumulation of proline has been observed in a large number of plant species in response to drought and salt stresses, suggesting a key role of this amino acid in plant stress adaptation. Upstream components of the proline biosynthesis signal transduction pathways are still poorly defined. We provide experimental evidence that phospholipase D (PLD) is involved in the regulation of proline metabolism in Arabidopsis thaliana.