We have used conical electron tomography in order to reconstruct neuronal organelles in thin sections of plastic embedded rat somato-sensory cortical tissue. The conical tilt series were collected at a 55 degrees tilt and at 5 degrees rotations, aligned using gold particles as fiduciary markers, and reconstructed using the weighted back projection algorithm. After a refinement process based on projection matching, the 3D maps showed the "unit membrane pattern" along the entire reconstructed volume. This pattern is indicative of the bilayer arrangement of phospholipids in biological membranes. Based on Fourier correlation methods as well as the visualization of the "unit membrane" pattern, we estimated resolutions of approximately 4 nm. To illustrate the prospective advantages of conical tomography, we segmented "coated" vesicles in the reconstructed volumes. These vesicles were comprised of a central core enclosing a small lumen, and a protein "coating" extending into the cytoplasm. The "coated" vesicle was attached to the plasma membrane through a complex structure shaped as an arch where the ends are attached to the membrane and the crook is connected to the vesicle. We concluded that conical electron tomography of thin-sectioned specimens provides a powerful experimental approach for studying thin-sectioned neuronal organelles at resolution levels of approximately 4 nm.
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http://dx.doi.org/10.1016/j.jsb.2005.05.008 | DOI Listing |
BMC Oral Health
January 2025
Department of Prosthodontics, Faculty of Dentistry, Hacettepe University, 06230, Sıhhiye/Altındağ, Ankara, Turkey.
Background: The mechanical properties of framework materials significantly influence stress distribution and the long-term success of implant-supported prostheses. Although titanium, cobalt-chromium, zirconia, and polyether ether ketone (PEEK) are widely used, their biomechanical performance under dynamic loading conditions remains insufficiently investigated. This study aimed to evaluate the biomechanical behavior of four framework materials with different Young's modulus using dynamic finite element stress analysis.
View Article and Find Full Text PDFBMC Oral Health
January 2025
Department of Dental Implantology, Jinan Stomatological Hospital, Jinan, 250002, Shandong, People's Republic of China.
Objective: To study the biomechanical changes induced by differences in perioral force in patients with missing anterior maxillary teeth at rest via finite element analysis (FEA).
Methods: Using conical beam CT (CBCT) images of a healthy person, models of the complete maxillary anterior dental region (Model A) and maxillary anterior dental region with a missing left maxillary central incisor (Model B) were constructed. The labial and palatine alveolar bone and tooth surface of the bilateral incisor and cusp regions were selected as the application sites, the resting perioral force was applied perpendicular to the tissue surface, and the changes in maxillary stress and displacement after the perioral force was simulated were analyzed.
Am J Sports Med
January 2025
Department of Sports Medicine, Peking University Third Hospital, Institute of Sports Medicine of Peking University, Beijing, China.
Retina
January 2025
State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, China.
Purpose: To determine the impact of eye shape using three-dimensional magnetic resonance imaging on myopic maculopathy (MM) progression.
Methods: At baseline, 67 participants with high myopia were selected. Eye shape was classified into spheroidal, ellipsoidal, temporally distorted, nasally distorted, conical, and barrel-shape identified from three-dimensional magnetic resonance imaging.
Otol Neurotol
January 2025
Department of Otolaryngology-Head and Neck Surgery, Mayo Clinic, Jacksonville, Florida.
Objective: To analyze cases of medial migration of vestibular schwannomas to propose an underlying mechanism.
Study Design: Retrospective chart review.
Patients: Ten patients from one institution with sporadic vestibular schwannomas that demonstrated medial migration toward the cerebellopontine angle on serial imaging were reviewed.
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