Chopper
Chopper - Related Videos
05:45
Cultivating Ex Vivo Patient-Derived Glioma Organoids Using a Tissue Chopper
0 Views •
Cited by 2 •
2024
This study introduces an automated method to generate patient-derived glioblastoma 3-dimensional organoids utilizing a tissue chopper. The method provides a suitable and effective approach to obtain such organoids for therapeutical testing.
05:02
Cerebellum Dissection and Slice Preparation: A Method to Generate Tissue Slices from Mouse Cerebellum
0 Views •
2025
This video describes a method to generate tissue slices from the mouse cerebellum. The cerebellar slices can be used for organotypic culturing that provides insights into neurodevelopmental mechanisms, including myelination dynamics.
10:06
Non-Laser Capture Microscopy Approach for the Microdissection of Discrete Mouse Brain Regions for Total RNA Isolation and Downstream Next-Generation Sequencing and Gene Expression Profiling
0 Views •
Cited by 11 •
2011
RNA expression profiling of discrete mouse brain regions requires a precise and repeatable tissue collection strategy. A protocol that uses both coronal brain sectioning and tissue corer-assisted microdissection is described here. The yield and quality of total RNA obtained from the resulting samples confirms the utility of the outlined method.
05:18
A Rapid and Chemical-free Hemoglobin Assay with Photothermal Angular Light Scattering
0 Views •
Cited by 1 •
2016
A photo-thermal angular light scattering (PT-AS) sensor enables the rapid and chemical-free hemoglobin assay of nanoliter-scale blood samples. Here, details of the PT-AS setup and a measurement protocol for the hemoglobin concentration in blood are provided. Representative results for anemic blood samples are also presented.
05:54
Rapid Culturing of Primary Murine Melanocytes and Fibroblasts: Isolating Melanocytes and Fibroblasts from Whole Murine Skin Sample
0 Views •
2023
This video describes the rapid method to isolate and culture the melanocytes and fibroblast simultaneously from the postnatal mouse pup’s skin. These cells can be maintained and manipulated in vitro to study skin cell biology, wound healing, and melanoma.
FAQs
A Chopper creates a time-varying analytical signal at a controlled frequency, while steady background radiation does not receive that same modulation. The lock-in amplifier can therefore select the detector response associated with the chopping frequency instead of treating all detected radiation equally. This frequency-based separation helps reveal weak chemical signals that would otherwise be obscured.
The chopping frequency supplies a controlled timing pattern that the detector and lock-in amplifier can recognize. Matching the signal analysis to this pattern helps separate the desired response from steady background radiation, electronic noise, and instrument drift. Consequently, frequency-controlled modulation improves the reliability of measurements in which the analyte signal is small.
An unmodulated measurement presents the detector with the analytical signal together with background radiation and changes caused by instrument drift. Periodic interruption gives the analytical response a distinguishable time pattern, allowing the detection system to discriminate it from steady contributions. This approach is especially valuable when environmental or instrumental effects could conceal a weak chemical signal.
A rotating disk containing slots or alternating open and closed sections is positioned so that it periodically interrupts the light beam. The detector then records the resulting modulated response, while a lock-in amplifier analyzes the component associated with the controlled interruption frequency. This arrangement connects mechanical beam modulation with selective electronic signal detection.
Choppers support measurements in infrared, fluorescence, and photothermal spectroscopy. In each case, the device modulates the beam so the detection system can distinguish the analytical response from steady background radiation and other unwanted contributions. Their use is therefore relevant across several chemical spectroscopy methods, particularly when the measured signal is weak or environmental interference is significant.
By separating a modulated analytical response from background radiation, electronic noise, and instrument drift, a Chopper can improve the signal-to-noise ratio and measurement reliability. The controlled modulation also supports quantitative analysis when analyte signals are small. These benefits help analytical instruments produce more dependable results under conditions where direct detection would be difficult.