scholarly journals High-resolution 4-D acquisition of freely swimming human sperm cells without staining

2020 ◽  
Vol 6 (15) ◽  
pp. eaay7619 ◽  
Author(s):  
Gili Dardikman-Yoffe ◽  
Simcha K. Mirsky ◽  
Itay Barnea ◽  
Natan T. Shaked
Keyword(s):  
Refractive Index ◽  
High Resolution ◽  
Sperm Cell ◽  
High Speed ◽  
Three Dimensional ◽  
Human Sperm ◽  
Refractive Index Profile ◽  
Sperm Cells ◽  
Biological Assays ◽  
Natural Movement

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.

scholarly journals Expression and function of ras proto-oncogene proteins in human sperm cells

1992 ◽  
Vol 102 (3) ◽  
pp. 487-494 ◽  
Author(s):  
R.K. Naz ◽  
K. Ahmad ◽  
P. Kaplan
Keyword(s):  
Sperm Cell ◽  
Acrosome Reaction ◽  
Cell Function ◽  
Beat Frequency ◽  
Human Sperm ◽  
Sperm Cells ◽  
Ras Protein ◽  
Head Displacement ◽  
Sperm Penetration ◽  
And Function

The presence and role of c-ras proteins were investigated in mature human sperm cells. The v-H-ras monoclonal antibody (mAb) against the c-ras protein, p21, reacted specifically with the acrosomal region of methanol-fixed as well as unfixed-live capacitated and non-capacitated human sperm cell in the indirect immunofluorescence technique. The v-H-ras mAb predominantly recognized c-ras protein of 21 kDa on the Western blot of lithium diiodosalicylate (LIS)-solubilized human sperm preparation. The incubation of sperm cells with v-H-ras mAb affected the sperm cell function in the human sperm penetration assay. The antibody significantly reduced the acrosome reaction and release of acrosin activity from the sperm cells. There was no effect of the mAb on percentage motility, although the mAb significantly affected various motility characteristics such as linearity, amplitude of lateral head displacement (ALH) and beat frequency, the motility parameters involved in the hyperactivation phenomenon of sperm cells leading to capacitation and acrosome reaction. These results suggest that the c-ras or c-ras-like proteins are present in mature sperm cell and may have a role in capacitation and/or acrosome reaction of human sperm cell.

Microwave Photonic Interrogation of a High-Speed and High-Resolution Multipoint Refractive Index Sensor

2021 ◽  
pp. 1-1
Author(s):  
Guangying Wang ◽  
Baoliang Liao ◽  
Yuan Cao ◽  
Tuan Guo ◽  
Xinhuan Feng ◽  
...  
Keyword(s):  
Refractive Index ◽  
High Resolution ◽  
High Speed ◽  
Refractive Index Sensor ◽  
Microwave Photonic

"ON-AXIS" LINEAR FOCUSED SPOT SCANNING MICROSTEREOLITHOGRAPHY SYSTEM: OPTOMECHATRONIC DESIGN, ANALYSIS AND DEVELOPMENT

2013 ◽  
Vol 12 (01) ◽  
pp. 43-68 ◽  
Author(s):  
PRASANNA GANDHI ◽  
SUHAS DESHMUKH ◽  
RAHUL RAMTEKKAR ◽  
KIRAN BHOLE ◽  
ALEM BARAKI
Keyword(s):  
High Resolution ◽  
System Integration ◽  
High Speed ◽  
Mechanical Design ◽  
Three Dimensional ◽  
Layer By Layer ◽  
Optical Scanning ◽  
High Production Rate ◽  
High Production ◽  
Scanning Mechanism

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.

scholarly journals Human sperm uses asymmetric and anisotropic flagellar controls to regulate swimming symmetry and cell steering

2020 ◽  
Vol 6 (31) ◽  
pp. eaba5168 ◽  
Author(s):  
Hermes Gadêlha ◽  
Paul Hernández-Herrera ◽  
Fernando Montoya ◽  
Alberto Darszon ◽  
Gabriel Corkidi
Keyword(s):  
High Speed ◽  
Reproductive Tract ◽  
Three Dimensional ◽  
Human Sperm ◽  
Bilateral Symmetry ◽  
Female Reproductive Tract ◽  
Optical Illusion ◽  
3D Microscopy ◽  
Molecular Components ◽  
Molecular Asymmetries

Flagellar beating drives sperm through the female reproductive tract and is vital for reproduction. Flagellar waves are generated by thousands of asymmetric molecular components; yet, paradoxically, forward swimming arises via symmetric side-to-side flagellar movement. This led to the preponderance of symmetric flagellar control hypotheses. However, molecular asymmetries must still dictate the flagellum and be manifested in the beat. Here, we reconcile molecular and microscopic observations, reconnecting structure to function, by showing that human sperm uses asymmetric and anisotropic controls to swim. High-speed three-dimensional (3D) microscopy revealed two coactive transversal controls: An asymmetric traveling wave creates a one-sided stroke, and a pulsating standing wave rotates the sperm to move equally on all sides. Symmetry is thus achieved through asymmetry, creating the optical illusion of bilateral symmetry in 2D microscopy. This shows that the sperm flagellum is asymmetrically controlled and anisotropically regularized by fast-signal transduction. This enables the sperm to swim forward.

Correct ray-tracing analysis for interference microscopy of fibres

1995 ◽  
Vol 450 (1938) ◽  
pp. 23-36 ◽  
Keyword(s):  
Refractive Index ◽  
Ray Tracing ◽  
High Speed ◽  
Nonlinear Least Squares ◽  
Fibre Surface ◽  
Refractive Index Profile ◽  
Initial Result ◽  
Interference Microscopy ◽  
Radial Density ◽  
Round Cross Section

A ray-tracing analysis for calculating, by means of interference microscope data, the radial distribution of refractive index, n ( r ), for fibres of round cross section has been formulated, solved, tested and used to determine n ( r ) for high-speed direct-spun polyethylene terephthalate (PET) fibres. The formulation was based on work by Kahl & Mylin (1965) originally performed to explore the radial density profiles in cylindrically symmetrical explosions. The equations were formulated with proper boundary conditions at the fibre surface, correcting a fundamental error that has caused problems for 20 years. This correct boundary condition unfortunately made it impossible to invert, as had been done in all previous work, the resulting integral equations, which consequently were solved by a nonlinear least-squares approximation. The analysis corrected a serious problem noted in the literature: namely, that the refractive index profile obtained for a particular fibre depended on the refractive index of the immersion liquid used to make the measurement. Refractive index profiles observed for PET fibres produced by high-speed direct spinning had concave-down curvature, the opposite of expectations based on previous work. This initial result suggests that when direct-spun, under crystallizing conditions, PET fibres develop a mainly radial density or quench profile, whereas fibres spun under conditions that give little crystallinity have a mainly radial orientation gradient. Experiments to test this suggestion further have not been done yet.

scholarly journals Validating marker-less pose estimation with 3D x-ray radiography

2021 ◽  
Author(s):  
Dalton D Moore ◽  
Jeffrey D Walker ◽  
Jason N MacLean ◽  
Nicholas G Hatsopoulos
Keyword(s):  
Pose Estimation ◽  
High Speed ◽  
Full Range ◽  
Three Dimensional ◽  
Small Degree ◽  
X Ray ◽  
Neural Recordings ◽  
Radiography System ◽  
Median Error ◽  
Natural Movement

To reveal the neurophysiological underpinnings of natural movement, neural recordings must be paired with accurate tracking of limbs and postures. Here we validate the accuracy of DeepLabCut (DLC) by comparing it to a 3D x-ray video radiography system that tracks markers placed under the skin (XROMM). We record behavioral data simultaneously with XROMM and high-speed video for DLC as marmosets engage in naturalistic foraging and reconstruct three-dimensional kinematics in a shared coordinate system. We find that DLC tracks position and velocity of 12 markers on the forelimb and torso with low median error (0.272 cm and 1.76 cm/s, respectively) corresponding to 2.9% of the full range of marker positions and 5.9% of the range of speeds. For studies that can accept this relatively small degree of error, DLC and similar marker-less pose estimation tools enable the study of more naturalistic, unconstrained behaviors in many fields including non-human primate motor control.

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