search.noResults

search.searching

note.createNoteMessage

search.noResults

search.searching

orderForm.title

orderForm.productCode
orderForm.description
orderForm.quantity
orderForm.itemPrice
orderForm.price
orderForm.totalPrice
orderForm.deliveryDetails.billingAddress
orderForm.deliveryDetails.deliveryAddress
orderForm.noItems
Highlights from Instrumentation and Software


Optimization of T ree-Dimensional (3D) Chemical Imaging by Soſt X-Ray Spectro-Tomography Using a Compressed Sensing Algorithm by J Wu, M Lerotic, R Leary, S Collins, Z Saghi, P Midgley, V Berejnov, D Susac, J Stumper, G Singh, and AP Hitchcock, Microsc Microanal 23(5) (2017) 951–56


X-ray spectro-tomography provides 3D chemical mapping based on X-ray absorption properties. Radiation damage is intrinsic to X-ray absorption, so it is important to fi nd ways to maximize useful information within a given dose. For tomography, using the smallest number of tilt series images that gives a faithful reconstruction is one such method. We show that compressed sensing (CS) methods applied to tomographic reconstruction provides faithful 3D reconstructions with a much smaller number of 2D projection images than required for conventional simulta- neous iterative reconstruction technique (SIRT) reconstruction. We compare weighted back-projection, SIRT, and CS reconstruc- tions applied to high-angle annular dark fi eld scanning TEM (HAADF-STEM) and scanning transmission X-ray microscopy (STXM) tomography data sets. T e eff ects of varying tilt angle increment and angular range on the tomographic reconstructions are examined. Optimization of the regularization parameter in CS reconstruction is explored and discussed. T e comparisons show that CS provides improved reconstruction fi delity relative to SIRT, with increasing advantages as the number of tilt angles or the angular range is reduced.


Soſt


X-Y and X-Z slices from 3D distributions of polyacyrlate in polystyrene microspheres inside a carbon nanopipette in water, derived from 23-energy C 1s STXM spectro-tomograms with (left) full (±90°, 46 angles) and (right) reduced (±62°, 16 angles) tilt angle ranges, processed by SIRT and CS.


Techniques and Biological Applications


Quantitative Studies of Endothelial Cell Fibronectin and F-Actin Co-Alignment in Response to Shear Stress by X Gong, X Zhao, B Li, Y Sun, M Liu, Y Huang, X Jia, J Ji, and Y Fan, Microsc Microanal 23(5) (2017) 1013–23


Exploring the relationship between the fi bronectin (FN) and F-actin


fi ber alignment of endothelial cells (ECs) under mechanical stimuli is crucial to improve our understanding of the role that the extracellular matrix and cytoskeletal fi ber alignment play in EC function and vascular graſt development. Current studies are hampered by the lack of a reliable and sensitive quantifi - cation method of FN orientation. We have developed a feature enhancement method based on MATLAB to quantify FN and F-actin orientation. Our method divided the grayscale image converted from the original fl uorescence images into a set of nonoverlapping blocks. T e single local orientation in each block was defi ned by computing the orientation angle at the corresponding block center. T us we obtained the locally constant direction of the unclear, broken, and irregular FN fi bers. Our results demonstrated that FN and F-actin co-distributed and co-aligned parallel to the fl ow direction and that F-actin alignment played an essential role in regulating FN alignment in response to shear stress. T ese fi ndings may provide new insight in vascular tissue engineering.


The fl uorescence images were fi rstly divided into a set of non-overlapping blocks after grayscale transformation and normalization. The orientation vector (blue arrows) in each block was defi ned by computing the orientation angle at the corresponding block center with the least mean square estimation algorithm. A locally constant direction of fi bers was thus obtained to represent an intrinsic property of the FN fi bers, which is helpful to distinguish unclear, broken, and irregular fi bers correctly.


48 doi: 10.1017/S1551929517001171 www.microscopy-today.com • 2018 January


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60