Asbestos in lung tissue

Asbestos is a potent carcinogen associated with malignant mesothelioma and lung cancer but its carcinogenic mechanisms are still poorly understood. Asbestos toxicity is ascribed to its particular physico-chemical characteristics, and one of them is the presence of and ability to adsorb iron, which may cause an alteration of iron homeostasis in the tissue. 


L. Pascolo et al., Scientific Reports 3, 1123, (2013)

Read More

Sealed Electrochemical Microcell

 

Dynamic studies in the realm of electrochemical materials science, able to follow morphochemical couplings under growth and operation conditions, are crucial to several technologies, among which are the following: electrochemical energetics (fuel cells, batteries, and supercapacitors), energy harvesting, catalysis, biosensing, and nanofabrication.
 
B. Bozzini et al., Anal. Chem. 2014, 86, 664−670.





In this paper we report on the fabrication and testing of a novel concept of sealed electrochemical microcell for in situ soft X-ray microspectroscopy in transmission, dedicated for nonvacuum compatible electrolytes. The microcell, fabricated using ultraviolet lithography, at variance with previous versions of electrochemical wet cells, that featured an optical window glued on top of the electrode system and a very limited electrolyte volume, the device presented here is a single solid block based around a microfabricated channel with fixed optical windows and apt for microfluidic work.
The first electrochemical experiments with this new cell explore the electrochemical growth of a Co-polypyrrole, a composite electrocatalyst material with promising performance to replace the expensive Pt catalyst in fuel-cell oxygen electrodes. 
  Morphological and chemical-state distributions of Co codeposited with polypyrrole has been followed as a function of time and position, yielding unprecedented information on the processes relevant to the synthesis of this catalyst.

Retrieve article

Fabrication of  a Sealed Electrochemical Microcell for in Situ X-ray Miscospectroscopy and Testing with in Situ Co-Polypyrrole Composite Electrodeposition for Pt-Free Oxygen Electrocatalysis; B. Bozzini, A. Gianoncelli, P. Bocchetta, S. Dal Zilio, G. Kourousias;
Analitycal Chemistry 2014 , 86, 664-670;
doi.org/10.1021/ac403004v  

Read More

Spectromicroscopy using Ptychography

Ptychography is a form of scanning diffractive imaging that can successfully retrieve the modulus and phase of both the sample transmission function and the illuminating probe. An experimental difficulty commonly encountered in diffractive imaging is the large dynamic range of the diffraction data.

A. M. Maiden et al., Nature Communications 4, 1669 (2013).


In our work we report a novel ptychographic experiment using a randomly phased X-ray probe to considerably reduce the dynamic range of the recorded diffraction patterns. Images can be reconstructed reliably and robustly from this setup, even when scatter from the specimen is weak. A series of ptychographic reconstructions at X-ray energies around the L absorption edge of iron demonstrates the advantages of this method for soft X-ray 
spectromicroscopy, which can readily provide chemical sensitivity without the need for optical refocusing. In particular, the phase signal is in perfect registration with  the modulus signal and provides complementary information that can be more sensitive to changes in the local chemical environment.

Retrieve article

Soft X-ray spectromicroscopy using ptychography with randomly phased illumination
A. M. Maiden, G. R. Morrison, B. Kaulich, A. Gianoncelli, J. Rodenburg, Nature Communications 4, 1669 (2013)
doi:10.1038/ncomms2640.

Read More

Phase-diverse Fresnel CDI

Phase-diverse Fresnel CDI has been shown to reveal the structure and composition of biological specimens with high sensitivity at nanoscale resolution. However, the method has yet to be applied in the ‘water-window’ that lies between the carbon and oxygen K edges. This is a proof-of-principle application of FCDI in the water-window to dehydrated red blood cells infected with the trophozoite stage of the malaria parasite. 


M. Jones et al., Optics Express 2013 21, 32151-32159.








This study demonstrates the application of phase-diverse FCDI on both a fabricated test sample and cellular specimens in the water-window. The general shape of the host red blood cells and parasite can easily be recognised from the X-ray images and correlate well with the information provided by the other imaging modalities. Because of the ability to acquire the X-ray images with relatively low dose, the method can be used as a correlative microscopy tool to inform the interpretation of images obtained using electron and optical methods. In particular, internal features of the whole cell such as the exomembrane system of the parasite, which cannot be resolved at high resolution using light microscopy and which are inaccessible to scanning electron microscopy, can be distinguished in the X-ray images.

Retrieve article

Phase-diverse Fresnel coherent diffractive imaging of malaria parasite-infected red blood cells in the water window
M. W.M. Jones, B. Abbey, A. Gianoncelli, E. Balaur, C. Millet, M. B Luu, H. D. Couglan, A. J. Carroll, A. G. Peele, L. Tilley, G. A. van Riessen, Optics Express 21, 32151-32159, (2013) doi.org/10.1364/OE.21.032151  

 

Read More

Al toxicity in soybean roots

Aluminum is one of the major causes for soil degradation, in particular in acidic soils, where soil minerals release soluble Al that limits the growth of plants. Unfortunately, acidic soils comprise ca. 40% of the world’s arable land and are typically present in the areas that are more favorable for intensive agriculture. Our LEXRF show that the AL accumulation is rather rapid process and Al remains concentrated in cell walls with exposure time.


P. Kopittke et al., Plant Physiology (2015)




The results obtained in this study have revealed that toxic effects of aluminum are already exerted within the first 5-30 min of exposure in specific cells located in a region approximately 5-10 mm behind the root tip. Since traditional techniques are not sensitive to access accumulation of aluminum in these initial stages we used a combination of synchrotron-based low-energy X-ray fluorescence spectromicroscopy (LEXRF) at the TwinMic beamline (Elettra Sincrotrone Trieste) and high-resolution secondary ion mass spectroscopy (NanoSIMS) to examine the spatial distribution of Al on a cellular and subcellular level. This integrated approach allowed us to identify the sequence of processes whereby Al reduces the growth of roots in rather short term. The obtained results demonstrate that the majority of Al starts to accumulate within the walls of cells in the outer root tissues (as shown in Figure 1) and this preferential storage in the walls of the outer tissues continues even after exposures of 24 h (Figure 2). This observation is particularly important since the cells located in the region 5-10 mm behind the root tip are the ones responsible for the root growth via walls loosening.
Our findings clearly show that the accumulation of Al is rather rapid process and Al remains concentrated in the cell walls with exposure time. The binding of Al to the cell walls exerts toxic effects, leading to inhibition of cell elongation and growth. The results clearly indicate that for overcoming the deleterious effects of Al it is important to focus on traits related to cell wall composition as well as traits involved in wall loosening. 
 

Retrieve article

Identification of the primary lesion of toxic aluminum (Al) in plant roots
Peter M. Kopittke, Katie L. Moore, Enzo Lombi, Alessandra Gianoncelli, Brett J. Ferguson, F. Pax C. Blamey, Neal W. Menzies, Timothy M. Nicholson, Brigid A. McKenna, Peng Wang, Peter M. Gresshoff, George Kourousias, Richard I. Webb, Kathryn Green, Alina Tollenaere , Plant Physiology  (2015) doi: 10.1104/pp.114.253229.

Read More

Electrochemistry: Oxigen Reduction Reaction Electrocatalyst

Electrodeposition of manganese/polypyrrole (Mn/PPy) nanocomposites has been recently shown to be a technologically relevant synthesis method for the fabrication of Oxygen Reduction Reaction (ORR) electrocatalysts.



Bozzini et al., J. Mater. Chem. A (2015).






Novel non-noble metal/polypyrole composites have properties promising to be considered as substitutes of expensive platinum catalysts for the Oxygen Reduction Reaction (ORR) in energy devices, in particular in alkaline fuel cells. Following revelation the catalytic activity of cobalt phthalocyanine and the beneficial effect of pyrolysis at 400–800 °C on its stability and catalytic properties, considerable efforts have been made to explore the chemo-morphological transformations of non-precious metal-nitrogen–carbon composites (M/N/C, M¼Co, Fe, Mn, etc.) during pyrolysis in order to shed light on the modifications leading to the increased electrocatalytic activity. Up to date the majority of the results indicate the formation of MeN_x-type moieties as active catalytic sites. Among the different strategies to include nitrogen in the catalyst, electrochemistry offers the possibility of using polypyrrole (PPy) with its dual function as a N-source and an electronically conducting catalyst support for the electrodeposition of metal-containing composite materials.
We used a new approach for the fabrication of MnO₂/carbon and metal/PPy electrocatalysts that has allowed creation of more Mn/N/C catalytic active sites during the electrodeposition process. The work, coordinated by Prof. Benedetto Bozzini, is collaboration between the Department of Engineering and Innovation of Salento University, The Institute for Microelectronics and Microsystems, IMM-CNR and Elettra Iaboratory. The investigation combined material fabrication and characterization using clasical electrochemistry methods complemented with imaging and microspectroscopy methods available at the scanning microscopes operated at the TwinMic and ESCAMicroscopy beamlines at Elettra laboratory. In particular, at Elettra by using chemical mapping and X-ray absorption (XAS), fluorescence (XRF) and photoelectron XPS) microspectroscopy we were able to shed light on the evolution of both morphology and chemical composition of synthesized materials following in-situ their evolution under different fabrication conditions.
The representative calibrated Mn XRF images in Fig.1 clearly show the laterally inhomogeneous distribution at mesoscopic and submicrometric scales, achieved under low current densities, while the rationed Mn/O pinpoints the variations in the Mn oxidation state. Comparing the contrast levels of the two maps it is clear that the local concentration and chemical state of Mn are not fully correlated.

Read More

Soft X-ray Radiation Damage

Soft X-ray radiation damaged has been studed by combining 3 different and independent miscoscopy techniques: X-ray Microsocpy, AFM microscopy and FTIR spectromicroscopy. XRM has been used to cause the damage while AFM and FTIR, both non destructive methods, have been emplyed for investigating the effect of soft X-rays on fixed cells.

Gianoncelli et al. Scientific Reports (2015)

Read More