A Fibers
These myelinated fibers have a relatively large diameter and conduct impulses rapidly, mediating the sense of touch and proprioception.
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Most cited protocols related to «A Fibers»
Step one, fiber tractography (
Step two, fiber tract segmentation (
Step three, fiber tract refinement (
Diffusion properties are calculated at each node of each fiber using spline interpolation of the diffusion properties: fractional anisotropy FA, mean diffusivity (MD), radial diffusivity (RD) and axial diffusivity (AD). Properties are summarized at each node by taking a weighted average of the diffusion properties at that node on each fiber (
We chose one of the diffusion-weighted data sets included in the Q3 data release of the HCP39 (link), subject 100307, to perform whole-brain global fiber tractography52 , 68 (link). Among other customizations, the HCP scanners are equipped with a set of high-end gradient coils, enabling diffusion encoding gradient strengths of 100 mT m−1. By comparison, most standard magnetic resonance scanners feature gradient strengths of about 30 to 40 mT m−1. This hardware setup allows the acquisition of data sets featuring exceptionally high resolutions (1.25 mm isotropic, 270 gradient directions) while maintaining an excellent SNR. All data sets were corrected for head motion, eddy currents and susceptibility distortions and are, in general, of very high quality69 –73 (link). Detailed information regarding the employed imaging protocols as well as the data sets themselves may be found on
Global fiber tractography was performed using MITK Diffusion74 (link) with the following parameters: 900,000,000 iterations, a particle length of 1 mm, a particle width of 0.1 mm, and a particle weight of 0.002. Furthermore, we repeated the tractography six times and combined the resulting whole-brain tractograms into one large data set consisting of over five million streamlines. The selected parameters provided for a very high sensitivity of the tractography method. The specificity of the resulting tractogram was of lesser concern since the tracts of interest were extracted manually in the second step.
Bundle segmentation was performed by an expert radiologist using manually placed inclusion and exclusion regions of interest (ROI). We followed the concepts introduced in ref. 40 for the ROI placement and fiber extraction. Twenty-five bundles were extracted, covering association, projection, and commissural fibers across the whole brain (Fig.
After manual extraction, the individual long-range bundles were further refined to serve as ground truth for the image simulation as also shown in Fig.
Most recents protocols related to «A Fibers»
Example 2
In some applications, an infrasonic sensor is desired, with a frequency response fl that extends to an arbitrarily low frequency, such as a tenth of hundredth of a Hertz. Such a sensor might be useful for detecting fluid flows associated with movement of objects, acoustic impulses, and the like. Such an application works according to the same principles as the sonic sensor applications, though the length of individual runs of fibers might have to be greater.
In addition, the voltage response of the electrode output to movements is proportional to the velocity of the fiber, and therefore one would typically expect that the velocity of movement of fluid particles at infrasonic frequencies would low, leading to low output voltages. However, in some applications, the fluid movement is macroscopic, and therefore velocities may be appreciable. For example, in wake detection applications, the amplitude may be quite robust.
Generally, low frequency sound is detected by sensors which are sensitive to pressure such as infrasound microphones and microbarometers. As pressure is a scaler, multiple sensors should be used to identify the source location. Meanwhile, due to the long wave length of low frequency sound, multiple sensors have to be aligned far away to distinguish the pressure difference so as to identify the source location. As velocity is a vector, sensing sound flow can be beneficial to source localization. There is no available flow sensor that can detect infrasound flow in a broad frequency range with a flat frequency response currently. However, as discussed above, thin fibers can follow the medium (air, water) movement with high velocity transfer ratio (approximate to 1 when the fiber diameter is in the range of nanoscale), from zero Hertz to tens of thousands Hertz. If a fiber is thin enough, it can follow the medium (air, water) movement nearly exactly. This provides an approach to detect low frequency sound flow directly and effectively, with flat frequency response in a broad frequency range. This provides an approach to detect low frequency sound flow directly. The fiber motion due to the medium flow can be transduced by various principles such as electrodynamic sensing of the movement of a conductive fiber within a magnetic field, capacitive sensing, optical sensing and so on. Application example based on electromagnetic transduction is given. It can detect sound flow with flat frequency response in a broad frequency range.
For the infrasound detection, this can be used to detect manmade and natural events such as nuclear explosion, volcanic explosion, severe storm, chemical explosion. For the source localization and identification, the fiber flow sensor can be applied to form a ranging system and noise control to find and identify the low frequency source. For the low frequency flow sensing, this can also be used to detect air flow distribution in buildings and transportations such as airplanes, land vehicles, and seafaring vessels.
The infrasound pressure sensors are sensitive to various environmental parameters such as pressure, temperature, moisture. Limited by the diaphragm of the pressure sensor, there is resonance. The fiber flow sensor avoids the key mentioned disadvantages above. The advantages include, for example: Sensing sound flow has inherent benefit to applications which require direction information, such as source localization. The fiber flow sensor is much cheaper to manufacture than the sound pressure sensor. Mechanically, the fiber can follow the medium movement exactly in a broad frequency range, from infrasound to ultrasound. If the fiber movement is transduced to the electric signal proportionally, for example using electromagnetic transduction, the flow sensor will have a flat frequency response in a broad frequency range. As the flow sensor is not sensitive to the pressure, it has a large dynamic range. As the fiber motion is not sensitive to temperature, the sensor is robust to temperature variation. The fiber flow sensor is not sensitive to moisture. The size of the flow sensor is small (though parallel arrays of fibers may consume volume). The fiber flow sensor can respond to the infrasound instantly.
Note that a flow sensor is, or would be, sensitive to wind. The sensor may also respond to inertial perturbances. For example, the pressure in the space will be responsive to acceleration of the frame. This will cause bulk fluid flows of a compressible fluid (e.g., a gas), resulting in signal output due to motion of the sensor, even without external waves. This can be advantages and disadvantages depends on the detailed applications. For example, it can be used to detect flow distribution in the buildings. If used to detect infrasound, the wind influence be overcome by using an effective wind noise reduction approach.
Example 1
In this example, calcium carbonate crystallization (CaCO3) is used to deposit calcium carbonate on synthetic fibers. Calcium carbonate crystals were formed by mixing a CaCl2) solution and a NaCO3 solution and adding the mixture to a suspension of BAROLIFT® fibers. The resulting precipitated calcium carbonate on the fibers was in the form of discrete calcite crystals that were sparsely distributed about the outer surface of the fibers.
The shear thinning behavior of the resulting fiber additives was tested against that of untreated BAROLIFT® fibers. Both types of fibers were added to BARAZAN® D PLUS™ (viscosifier/suspension agent, available from Halliburton Energy Services, Inc.) in a concentration of 1.2 wt. %, and the shear viscosity for each solution was tested at different shear rates. The viscosity profile was obtained using a coaxial cylinder geometry (bob-cup) on an MCR501 rheometer (available from Anton Paar).
Example 2
In this example, calcium carbonate crystallization (CaCO3) is used to deposit calcium carbonate on synthetic fibers after an acid treatment is performed on the fibers. The acid treatment increases the population of calcium carbonate crystals formed on the outer surface of the fibers. A suspension of BAROLIFT® fibers was treated with 1M NaOH solution for 2 hours. Then, calcium carbonate crystals were formed on the fiber surface by mixing a CaCl2 solution and a NaCO3 solution and adding the mixture to the fibers. The resulting precipitated calcium carbonate on the fibers was in the form of discrete calcite crystals that were more concentrated on the outer surface of the fibers, as compared to the fiber additives of Example 1.
Example 4
A verification study for dry content levels of the fibre composition of the invention is presented herein.
The physical-mechanical properties of the body, also referred to as volume-to-mass ratio, (cm3/g), tensile index (Nm/g), bursting index (KPam2/g) and tear index (mNm2/g) for different dry content (%) were analyzed.
The results obtained in this study are portrayed in
Through the results, it was concluded that there was a significant body, also referred to as volume-to-mass ratio, gain after 30% dry content and a loss of tensile strength after 30% dry content. Additionally, it was observed that the dry content did not significantly affect the tear strength. Regarding the bursting rate, no significant changes were observed between the dry content levels of 10, 20, 30, and 50%. Therefore, it is clear that redispersibility was achieved up to a maximum of 50% dry content.
pulp was oxidized at 1 wt % consistency, at pH 10, with 5 mmol of
NaClO as the spent oxidizer, and with 0.1 g of NaBr and 0.016 g of
TEMPO per gram of fiber as co-catalysts, as described in previous
works.30 (link),31 (link) The carboxyl content of the oxidized pulp,
once thoroughly washed with distilled water, accounted for 0.73 ±
0.01 mmol −COOH g–1, as estimated by Davidson’s
methylene blue adsorption method.32 (link) Its
intrinsic viscosity, measured by the capillary viscometer procedure
(TAPPI T 230 om-08),33 was 2.37 dL g–1. From the Mark–Houwink parameters for cellulose
in copper(II) ethylenediamine, as reported elsewhere,34 (link),35 (link) this corresponds to a degree of polymerization of 390.
Fibrillation
was carried out in a high-pressure homogenizer, NS1001L PANDA 2 K-GEA
(GEA Niro Soavi, Parma, Italy). A suspension of oxidized fibers was
passed three times at 300 bar, three times at 600 bar, and three times
at 900 bar. A 0.1 wt %, suspension of the resulting CNFs exhibited
transmittance at 600 nm of 68%.
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More about "A Fibers"
These fibers have a relatively large diameter and are myelinated, enabling them to conduct impulses rapidly.
They are responsible for mediating the sense of touch and proprioception, providing us with the ability to feel and perceive the position and movement of our body parts.
Researchers can utilize a variety of tools and techniques to study A Fibers, including MATLAB for data analysis, USB2000 and USB4000 for spectroscopic measurements, Fiber Analyzers for fiber characterization, QE65000 for low-light detection, and LabVIEW for instrument control and automation.
Additionally, the Rose Bengal stain can be used to visualize A Fibers, while the Eclipse Ti microscope and PM100D power meter can aid in detailed observation and measurement.
To enhance the reproducibility and accuracy of A Fibers research, researchers can leverage the cutting-edge protocol comparison tool offered by PubCompare.ai.
This AI-driven platform empowers users to effortlessly locate the best protocols from literature, preprints, and patents, ensuring that their investigations are based on the most reliable and up-to-date methodologies.
By utilizing PubCompare.ai's protocol comparison tool, researchers can make informed decisions and drive scientific breakthroughs in the study of A Fibers.
The S-4800 scanning electron microscope can also be employed to examine the intricate structure and morphology of A Fibers, providing valuable insights into their anatomy and function.
By combining these advanced tools and techniques, researchers can gain a deeper understanding of the role of A Fibers in the sensory and proprioceptive systems, and unlock new avenues for therapeutic interventions and scientific discoveries.