Jacob Staff
Jacob Staff - Related Videos
09:31
In Vitro Colony Assays for Characterizing Tri-potent Progenitor Cells Isolated from the Adult Murine Pancreas
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Cited by 8 •
2016
In vitro colony assays to detect self-renewal and differentiation of progenitor cells isolated from adult murine pancreas are devised. In these assays, pancreatic progenitors give rise to cell colonies in 3-dimensional space in methylcellulose-containing semi-solid medium. Protocols for handling single cells and characterization of individual colonies are described.
09:14
Enzymatic Cascade Reactions for the Synthesis of Chiral Amino Alcohols from L-lysine
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Cited by 7 •
2018
Chiral amino alcohols are versatile molecules for use as scaffolds in organic synthesis. Starting from L-lysine, we synthesize amino alcohols by an enzymatic cascade reaction combining diastereoselective C-H oxidation catalyzed by dioxygenase followed by cleavage of the carboxylic acid moiety of the corresponding hydroxyl amino acid by a decarboxylase.
09:36
Safety Precautions and Operating Procedures in an (A)BSL-4 Laboratory: 4. Medical Imaging Procedures
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Cited by 8 •
2016
Here, we present an overview of the preparation and animal handling procedures required to safely perform medical imaging in an animal biosafety level 4 laboratory. Computed tomography of a mock-infected guinea pig illustrates these procedures that may be used to evaluate the disease caused by a high consequence pathogen.
10:03
Isolation of CA1 Nuclear Enriched Fractions from Hippocampal Slices to Study Activity-dependent Nuclear Import of Synapto-nuclear Messenger Proteins
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Cited by 8 •
2014
We provide a detailed protocol for induction of long-term potentiation in the CA1 region of the hippocampus and the subsequent isolation of nuclear enriched fractions from the tetanized area of the slice. This approach can be used to determine activity dependent nuclear protein import in cellular models of learning and memory.
03:03
Amyloid Fibrils
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2020
Amyloid fibrils are aggregates of misfolded proteins. Under most circumstances, misfolded proteins are either refolded by chaperone proteins or degraded by the proteasome. However, in the case of a mutation or a disease, these proteins can accumulate to form large clusters and often further assemble to form elongated fibers, called fibrils. Amyloid deposits were observed as early as 1639 in the liver and the spleen. In 1854, Rudolph Virchow performed iodine staining, normally used to...
FAQs
The instrument relies on the geometric relationship between the position of the sliding crosspiece and the two lines of sight. One sighting edge is aligned with a reference point and another with the target, creating a measurable angular relationship. Reading the crosspiece position on the graduated rod then provides the basis for estimating relative direction, height, or distance.
The graduated rod provides a scale for recording the crosspiece position, while the crosspiece establishes the two sighting directions needed for comparison. Their interaction turns a visual alignment into a repeatable reading rather than an informal estimate. Consistent alignment of the sighting edges is therefore essential for obtaining a meaningful geometric result in field surveying.
Alignment determines whether the reference point and target correspond correctly to the instrument's geometric reading. If a sighting edge is not directed toward the intended point, the recorded crosspiece position represents a different angular relationship and can affect estimated distance, height, or relative position. Careful visual alignment is consequently central to reliable field measurements.
Jacob Staff uses direct visual alignment and geometric reading, so it demonstrates measurement principles without relying on electronic instrumentation. Modern electronic instruments provide greater precision, making them more suitable when highly accurate results are required. The older device remains useful where the goal is to understand basic surveying geometry, practice field observation, or illustrate how measurements relate to angles.
A user positions the staff, identifies a reference point and a target, and aligns the instrument's sighting edges with both points. The sliding crosspiece is then adjusted to establish the required visual relationship, and its position is read from the graduated rod. That reading is interpreted through geometric relationships to estimate the desired field quantity.
In engineering and surveying instruction, the instrument connects observable field alignments with geometric measurement. Students can use it to explore how angular relationships support estimates of distance, height, and relative position, while also examining the practical limits of non-electronic tools. It also provides historical context for topographic mapping, land measurement, and basic astronomical or navigational observations.