Search results for "Microscopy"

Microfabricated high temperature sensing platform dedicated to scanning thermal microscopy (SThM)

2018

Abstract The monitoring of heat flux is becoming more and more critical for many materials and structures approaching nanometric dimensions. Scanning Thermal Microscopy (SThM) is one of the tools available for thermal measurement at the nanoscale and requires calibration. Here we report on a micro-hotplate device made of a platinum heater suspended on thin silicon nitride (SiN) membranes integrating specific features for SThM calibration. These heated reference samples can include a localized resistive temperature sensors (RTD) or standalone platinum membranes (typically 10 × 10 μm2) on which the temperature can be measured precisely. This functional area is dedicated to (1) estimate the th…

Effect of surface disorder on the domain structure of PLZT ceramics

2017

ABSTRACTPb1-xLax(Zr0.65Ti0.35)1-x/4O3 (PLZT x/65/35) ceramics were studied by Piezoresponse Force Microscopy in order to understand the origin of domain structure as a function of La content. We show that the domain topology is mainly determined by the composition and grain size. The characteristic correlation length decreases with increasing La content, being sensitive also to the synthesis method. The behavior of the correlation length is linked to the macroscopic properties, showing a strong increase of disorder with La doping. The roughness exponent for the domain wall in PLZT 9/65/35 is close to 2/3 indicating 1D character of domain walls in relaxors.

Hybrid GMP–polyamine hydrogels as new biocompatible materials for drug encapsulation

2020

Here we present the preparation and characterization of new biocompatible materials for drug encapsulation. These new gels are based on positively charged [1+1] 1H-pyrazole-based azamacrocycles which minimise the electrostatic repulsions between the negatively charged GMP molecules. Rheological measurements confirm the electroneutral hydrogel structure as the most stable for all the GMP-polyamine systems. Nuclear magnetic resonance (NMR) was employed to investigate the kinetics of the hydrogel formation and cryo-scanning electron microscopy (cryo-SEM) was used to obtain information about the hydrogel morphology, which exhibited a non-homogeneous structure with a high degree of cross-linking…

Ceramic raw materials: how to recognize them and locate the supply basins—mineralogy, petrography

2020

This tutorial paper is focused on the mineralogical-petrographic characterization of clayey raw materials with the purpose of sourcing supply basins and answering questions about the provenance of the corresponding archaeological ceramic artefacts. The first part gives general indications of how to profitably study archaeological ceramic thin sections through the polarizing microscope. Brief notes are provided on the theoretical basis of optical microscopy. A scheme is then provided for the petrographic description of ceramic samples, concerning the textural and compositional characteristics of aplastic inclusions and groundmass. Suggestions are also given for identifying any minero-petrogr…

Why should traceology learn from dental microwear, and vice-versa?

2019

Dental and artifact microwear analyses have a lot in common regarding the questions they address, their developmental history and their issues. However, few paleontologists and archeologists are aware of this, and even those who are, do not take into account most of the methodological insights from the other field. In this focus article, we briefly review the main developmental steps of both methods, highlight how similar their histories are and how combining methodological developments can improve both research fields. In both cases, the traditional analyses have been strongly criticized mainly because of their subjectivity and their lack of repeatability and reproducibility. Quantitative …

Evolutionary convergence in conodonts revealed by Synchrotron-based Tomographic Microscopy

2016

Biochemical characterization of the skeletal matrix of the massive coral, Porites australiensis - The saccharide moieties and their localization.

2018

11 pages; International audience; To construct calcium carbonate skeletons of sophisticated architecture, scleractinian corals secrete an extracellular skeletal organic matrix (SOM) from aboral ectodermal cells. The SOM, which is composed of proteins, saccharides, and lipids, performs functions critical for skeleton formation. Even though polysaccharides constitute the major component of the SOM, its contribution to coral skeleton formation is poorly understood. To this end, we analyzed the SOM of the massive colonial coral, Porites australiensis, the skeleton of which has drawn great research interest because it records environmental conditions throughout the life of the colony. The coral …

Gibberellin reactivates and maintains ovary-wall cell division causing fruit set in parthenocarpic Citrus species

2016

[EN] Citrus is a wide genus in which most of the cultivated species and cultivars are natural parthenocarpic mutants or hybrids (i.e. orange, mandarin, tangerine, grapefruit). The autonomous increase in GA(1) ovary concentration during anthesis was suggested as being the stimulus responsible for parthenocarpy in Citrus regardless of the species. To determine the exact GA-role in parthenocarpic fruit set, the following hypothesis was tested: GA triggers and maintains cell division in ovary walls causing fruit set. Obligate and facultative parthenocarpic Citrus species were used as a model system because obligate parthenocarpic Citrus sp (i.e. Citrus unshiu) have higher GA levels and better n…

From the roots to the stem: unveiling pear root colonization and infection pathways by Erwinia amylovora

2020

ABSTRACT Fire blight caused by Erwinia amylovora affects pome fruit worldwide, generating serious economic losses. Despite the abundant literature on E. amylovora infection mechanisms of aerial plant organs, root infection routes remain virtually unexplored. Assessing these infection pathways is necessary for a full understanding of the pathogen's ecology. Using the pathosystem Pyrus communis–E. amylovora and different experimental approaches including a green fluorescent protein transformant (GFP1) and epifluorescence microscopy (EFM) and laser confocal scanning microscopy (LCSM), we demonstrated the pathogen's ability to infect, colonize and invade pear roots and cause characteristic fire…

Open data and digital morphology

2017

International audience; Over the past two decades, the development of methods for visualizing and analysing specimens digitally, in three and even four dimensions, has transformed the study of living and fossil organisms. However, the initial promise that the widespread application of such methods would facilitate access to the underlying digital data has not been fully achieved. The underlying datasets for many published studies are not readily or freely available, introducing a barrier to verification and reproducibility, and the reuse of data. There is no current agreement or policy on the amount and type of data that should be made available alongside studies that use, and in some cases…