Localized electrochemical deposition of copper monitored using real-time X-ray microradiography

We have developed a novel strategy for localized electrochemical deposition (LECD) to improve both the lateral resolution of the process and the porosity of the fabricated high-aspect-ratio microstructures. The strategy is based on accurately controlling the motion of the anode. Its implementation is made possible by the use of coherent, synchrotron X-ray microradiography with high time and lateral resolution, enabling the observation of the copper LECD process in real time. Microradiography reveals a deposition mechanism that differs as a function of the distance between the electrode (anode) and the growing structure (cathode). Specifically, the interplay of migration and diffusion of the metal ions in the baths affects the deposition rate and the characteristics of the fabricated structure. This enables us to optimize the anode motion control and greatly improve the quality of the structure grown.X1130sciescopu

Synchrotron X-ray microtomography for 3D imaging of polymer blends

Despite sufficient spatial resolution and routine operation, traditional electron microscopy (SEM and TEM) of polymer blend morphologies is limited to two dimensions (2D) and often requires tedious sample preparation. We have used a powerful X-ray imaging technique to visualize the morphology of polymer blends in three dimensions (3D). Images of polystyrene/high-density polyethylene (PS/HDPE) blend samples were constructed with microtomography using coherent synchrotron X-rays. Good contrast for blends with and without the PS phase removed (no other sample preparation was needed) was accomplished, and image quality is compared in the paper. High resolution (1 mu m) images of relatively thick (similar to 1 mm) blend samples were possible by adapting a sample stage equipped with high precision motor controls, by enhancing phase contrast through optimization of sample-scintillator distance, and by taking a large number of projection images (up to 1000) along different angles. Reconstructed slices were used to create 3D volume-rendered images of the blends. Coarsening of the cocontinuous morphology during annealing was monitored using extraction-free microtomography. Measurements of interfacial area per volume at varying annealing times agree with experimental results obtained using mercury porosimetry. It was also shown that SEM quantitative annealing results are limited at long annealing times due to the limitations of two-dimensional images of a three-dimensional morphology.X114442sciescopu

Imaging of renal and prostate carcinoma with refractive index radiology

Aim: Having better edge enhancement and penetrating power, refractive index radiology is suitable for the imaging of weakly absorbing objects such as tissue specimens. In this study the potential of refractive index radiology was evaluated for the imaging of renal cell carcinoma (RCC) and prostate cancer (PCA). Methods: Specimens were cut in 3 mm and 4 mu m thickness for X-ray radiology and hematoxylin and eosin (HE) staining, respectively. Radiographic images of RCC and PCA were obtained using the synchrotron hard X-rays from the 7B2 beam-line of the Pohang Light Source (PLS). The imaging technique applied was phase-contrast radiology based on the refraction enhancement mechanism. The resulting radiographic images were analyzed in correlation with those of optical microscopy. Results: Using unmonochromatized hard X-rays, it was possible to obtain images with clear edge enhancement and relatively large field of view (6 cm x 6 cm). Even with overlapping signals from thick samples (more than 700-fold thicker than microscopic images), radiographic images clearly showed histological information of organelles in normal kidney such as glomeruli, tubules, and collecting ducts. Histological information of RCC including tumor subtypes and minute changes such as cystic degeneration could be identified without difficulty. The radiographic images of the prostate were comparable with those of low magnification optical microscopy, providing good visualization of normal microstructures such as adenoma, smooth muscle, and normal glands, or differentiation of tiny tumors from surrounding normal tissues. Conclusions: These results suggest the potential of refractive index radiology to provide a new way of imaging biological tissues with low absorption contrast such as RCC and PCA.X1110sciescopu

Phase contrast radiography of Lewy bodies in Parkinson disease

Parkinson's disease (PD), defined as a neurodegenerative disorder, is characterized by the loss of dopaminergic neurons and the presence of Lewy bodies in neurons. Morphological study of Lewy bodies is important to identify the causes and the processes of PD. Here, we investigate a possibility of phase contrast radiography using coherent synchrotron X-rays to explore the microscopic details of Lewy bodies in thick (similar to 3 mm) midbrain tissues. Autopsied midbrain tissues of a PD patient were sliced in 3 mm thickness and then examined using synchrotron X-rays from the 7B2 beamline of the Pohang Light Source. Refraction-enhanced phase contrast radiography and microtomography were adopted to identify dark core and dim edge of Lewy bodies in neurons. The morphology of Lewy bodies was clearly revealed by the phase contrast radiography in very thick (3 mm) midbrain tissues without any staining treatment. Three-dimensional volume rendered microtomography of the autopsied midbrain tissues demonstrates striking evidence that several Lewy bodies are agglomerated by dim edges in a neuron. We suggest that the phase contrast radiography could be a useful tool to morphologically investigate the causes or the processes in PD. (c) 2006 Elsevier Inc. All rights reserved.X1111sciescopu

An Important Role of alpha-Hemolysin in Extracellular Vesicles on the Development of Atopic Dermatitis Induced by Staphylococcus aureus

Skin barrier disruption and dermal inflammation are key phenotypes of atopic dermatitis (AD). Staphylococcus aureus secretes extracellular vesicles (EVs), which are involved in AD pathogenesis. Here, we evaluated the role of EVs-associated alpha-hemolysin derived from S. aureus in AD pathogenesis. alpha-hemolysin production from S. aureus was detected using western blot analyses. The cytotoxic activity of alpha-hemolysin on HaCaT keratinocytes was evaluated by measuring cell viability after treating cells with soluble and EVs-associated alpha-hemolysin. To determine the type of cell death, HaCaT keratinocytes were stained with annexin V and 7-AAD. The in vivo effects of alpha-hemolysin were evaluated by application of soluble and EV-associated alpha-hemolysin on the mouse skin. The present study showed that increased alpha-hemolysin was produced by S. aureus colonized on AD patients compared to healthy subjects. alpha-hemolysin production was also related to AD severity. In addition, EV-associated alpha-hemolysin was more cytotoxic to HaCaT keratinocytes than soluble alpha-hemolysin, and alpha-hemolysin-negative EVs did not induce keratinocyte death. EV-associated alpha-hemolysin induced necrosis, but soluble alpha-hemolysin induced apoptosis of keratinocytes. In vivo, skin barrier disruption and epidermal hyperplasia were induced by soluble and EV-associated alpha-hemolysin. However, AD-like dermal inflammation was only caused by EV-associated alpha-hemolysin. Moreover, neither skin barrier disruption nor AD-like skin inflammation was induced by alpha-hemolysin-negative EVs. Taken together, alpha-Hemolysin secreted from S. aureus, particularly the EV-associated form, induces both skin barrier disruption and AD-like skin inflammation, suggesting that EV-associated alpha-hemolysin is a novel diagnostic and therapeutic target for the control of AD.open111618sciescopu