Search results for "Microfibril"
showing 8 items of 8 documents
Extracellular Assembly of the Elastin Cable Line Element in the Developing Lung
2017
In the normal lung, a dominant structural element is an elastic "line element" that originates in the central bronchi and inserts into the distal airspaces. Despite its structural importance, the process that leads to development of the cable line element is unknown. To investigate the morphologic events contributing to its development, we used optical clearing methods to examine the postnatal rat lung. An unexpected finding was numerous spheres, with a median diameter of 1-2 µm, within the primary septa of the rat lung. The spheres demonstrated green autofluorescence, selective fluorescent eosin staining, reactivity with carboxyfluorescein succinimidyl ester, and specific labeling with ant…
Improved Bone Regeneration Using Biodegradable Polybutylene Succinate Artificial Scaffold in a Rabbit Model
2022
The treatment of extensive bone loss represents a great challenge for orthopaedic and reconstructive surgery. Most of the time, those treatments consist of multiple-stage surgeries over a prolonged period, pose significant infectious risks and carry the possibility of rejection. In this study, we investigated if the use of a polybutylene succinate (PBS) micro-fibrillar scaffold may improve bone regeneration in these procedures. In an in vivo rabbit model, the healing of two calvarial bone defects was studied. One defect was left to heal spontaneously while the other was treated with a PBS scaffold. Computed tomography (CT) scans, histological and immunohistochemical analyses were performed …
Microtubules and the Establishment of Apparent Cell Wall Invaginations in Mesophyll Cells of Pinus silvestris L.
1995
Summary Ridges of cell wall material protruding into the cellular lumen are characteristic of Pinus silvestris mesophyll cells. These ridges, e.g., appear to increase the inner surface for optimal dispersal of organelles, especially of chloroplasts. We show that the ridges are the result of local, brace-like wall reinforcements deposited during early turgor-driven expansion growth of postmitotic cells. The reinforced sites resist expansion and become the base of deep, narrow folds representing the ridges, while the intervening thin-walled areas evaginate as the cell volume increases. Cell wall material is deposited uniformly after expansion to stabilize the protrusions. There is a distinct …
Online measurement of floc size, viscosity, and consistency of cellulose microfibril suspensions with optical coherence tomography
2021
AbstractIn this study, cellulose microfibril (CMF) suspensions were imaged during pipe flow at consistencies of 0.4%, 1.0%, and 1.6% with optical coherence tomography (OCT) to obtain images of the structure and the local velocity of the suspension. The viscosities obtained by combining pressure loss measurement with the OCT velocity data showed typical shear thinning behavior and were in excellent agreement with viscosities obtained with ultrasound velocity profiling. The structural OCT images were used to calculate the radial and the axial floc sizes of the suspension. A fit of power law to the geometrical floc size–shear stress data gave the same power law index for all consistencies, sug…
Characterization of micro-fibrillated cellulose fiber suspension flow using multi scale velocity profile measurements
2017
Rheological properties and boundary layer flow behavior of Micro Fibrillated Cellulose (MFC) suspended in water was studied using a novel velocity profiling rheometric technique. The method is based on measuring stationary velocity profiles of fluid flow in a straight tube simultaneously by Doppler Optical Coherence Tomography (DOCT) and by Ultrasound Velocity Profiling (UVP). The high resolution DOCT provides velocity profiles near the transparent tube wall, while UVP yields corresponding information in the interior parts of the flow. The data from the two instruments is combined into a comprehensive velocity profile including both the thin boundary layer near the wall and the interior par…
Rheological and Flocculation Analysis of Microfibrillated Cellulose Suspension Using Optical Coherence Tomography
2018
A sub-micron resolution optical coherence tomography device was used together with a pipe rheometer to analyze the rheology and flocculation dynamics of a 0.5% microfibrillated cellulose (MFC) suspension. The bulk behavior of the MFC suspension showed typical shear thinning (power-law) behavior. This was reflected in a monotonously decreasing floc size when the shear stress exceeded the yield stress of the suspension. The quantitative viscous behavior of the MFC suspension changed abruptly at the wall shear stress of 10 Pa, which was reflected in a simultaneous abrupt drop of the floc size. The flocs were strongly elongated with low shear stresses. With the highest shear stresses, the flocs…
Nanoporous kaolin – cellulose nanofibril composites for printed electronics
2017
Cellulose nano- and microfibrils (CNF/CMF) grades vary significantly based on the raw materials and process treatments used. In this study four different CNF/CMF grades were combined with kaolin clay pigment particles to form nanoporous composites. The attained composite properties like porosity, surface smoothness, mechanical properties and density properties depended strongly on the raw materials used. In general, higher kaolin content (~80 wt%) led to controllable shrinkage during drying, which resulted in improved dimensional stability of composites, compared to a lower kaolin content (~50 wt%). On the other hand, the use of a plasticizer and a high amount of CNF/CMF was essential to pr…
The role of hemostatic devices in neurosurgery. A systematic review.
2021
Hemostasis represents a fundamental step in every surgical procedure. During neurosurgical procedures, proper and robust hemostasis into confined spaces can significantly reduce the odds of perioperative complications. Over the decades, multiple methods have been applied, and several medical devices have been developed to promote and guarantee proper hemostasis. This study presents a systematic review of the most used intraoperative hemostatic methods and devices in neurosurgery. Insightful research was performed on the PubMed database according to the PRISMA guidelines. This comprehensive review of scientific literature represents a synoptic panel where the most used intraoperative hemosta…