Dynamic study of three-dimensional peroxynitrite flux in epileptic brain using high-speed and high-resolution photoacoustic imaging

Author(s):  
Yaguang Ren ◽  
Chengbo Liu
2013 ◽  
Vol 12 (01) ◽  
pp. 43-68 ◽  
Author(s):  
PRASANNA GANDHI ◽  
SUHAS DESHMUKH ◽  
RAHUL RAMTEKKAR ◽  
KIRAN BHOLE ◽  
ALEM BARAKI

Microstereolithography (MSL) is technology of fabrication of three-dimensional (3D) components by using layer-by-layer photopolymerization. Typical design goals of MSL system are: small features, high resolution, high speed of fabrication, and large overall size of component. This paper focuses on design and development of such a system to meet these optomechatronic requirements. We first analyze various optical scanning schemes used for MSL systems along with the proposed scheme via optical simulations and experiments. Next, selection criteria for various subsystems are laid down and appropriate design decisions for the proposed system are made. Further, mechanical design of the scanning mechanism is carried out to meet requirements of high speed and resolution. Finally, system integration and investigation in process parameters is carried out and fabrication of large microcomponent with high resolution is demonstrated. The proposed system would be useful for fabrication of multiple/large microcomponents with high production rate in various applications.


2020 ◽  
Vol 6 (15) ◽  
pp. eaay7619 ◽  
Author(s):  
Gili Dardikman-Yoffe ◽  
Simcha K. Mirsky ◽  
Itay Barnea ◽  
Natan T. Shaked

We present a new acquisition method that enables high-resolution, fine-detail full reconstruction of the three-dimensional movement and structure of individual human sperm cells swimming freely. We achieve both retrieval of the three-dimensional refractive-index profile of the sperm head, revealing its fine internal organelles and time-varying orientation, and the detailed four-dimensional localization of the thin, highly-dynamic flagellum of the sperm cell. Live human sperm cells were acquired during free swim using a high-speed off-axis holographic system that does not require any moving elements or cell staining. The reconstruction is based solely on the natural movement of the sperm cell and a novel set of algorithms, enabling the detailed four-dimensional recovery. Using this refractive-index imaging approach, we believe that we have detected an area in the cell that is attributed to the centriole. This method has great potential for both biological assays and clinical use of intact sperm cells.


Author(s):  
John K. Stevens ◽  
Judy Trogadis

The cytoskeleton plays a direct role in controlling neurite shape. To quantitatively study both the three dimensional shape and the sub-micron structure of the cytoskeleton requires complete serial reconstruction at the Electron Microscopic level. We have devised a computer reconstruction system specifically for this purpose.The system uses a 35mm film copy of 3.25 x 4.00 inch EM negative as the data source. The film is placed into a high speed film transport (15 frames/second), which is mounted on a X,Y and rotation stage controlled by stepping motors. The 35mm film is viewed through a stepping motor controlled zoom lens mounted on a high resolution (1119 x 1024) video camera. A high resolution frame grabber controlled by the computer can store one complete frame. Thus, the live image and a stored image may be displayed alternately on a high resolution monitor. Finally, a graphics overlay and mouse connected to the computer can be used to align successive sections via the stepping motors, as well as to trace the outlines of a profile, or of a microtubule.


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