The mechanisms behind the propensity of chiral constrained Cα-tetrasubstituted amino acids (cCTAAs) to induce one particular helical screw sense, when included in the Ac-Aib2-cCTAA-Aib2-NHMe peptide model, were studied through replica exchange molecular dynamics, potential of mean force, and quantum theory of atoms in molecules calculations. We observed that cCTAAs exert their effect on helical screw sense selectivity through the positioning of the side chain to generate steric hindrance in either the (-x, +y, +z) or (+x, +y, -z) sectors of a right-handed 3D Cartesian space, where the z axis corresponds to the axis of the helix and the Cα lies on the +y semiaxis (0, +y, 0). The different strengthening of the noncovalent interactions, also comprising C-H···O interactions, exerted by the cCTAA in the right-handed or left-handed helix was also found important to define the preference of a cCTAA for a particular helix screw sense.
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http://dx.doi.org/10.1021/acs.jpcb.5b07050 | DOI Listing |
J Orthop Surg Res
February 2025
Department of Orthopaedics, Peking University Third Hospital, 49 Huayuan N Rd, 100191, Bei Jing Shi, Hai Dian Qu, China.
Background: This study aimed to evaluate and compare the clinical effects and complications of cannulated compression headless screws (CHS) and anatomical locking compression hook plates (LCP) for fractures of the displaced fifth metatarsal base zone I in athletes and young adults.
Methods: Between May 2021 and June 2023, 50 patients were retrospectively evaluated. The patients were divided into two groups according to the fixation method: screw (CHS group, n = 20) or plate (LCP group, n = 30).
Sci Rep
February 2025
Chair for Electrical Measurements and Sensor Technology, Technische Universität Chemnitz, Reichenhainer Str. 70, 09126, Chemnitz, Germany.
Bolted connections are extensively used in construction and machine design, playing critical roles in various industrial applications. Bolts and screws are, however, prone to loosening or separating due to factors such as shock, vibration, and temperature fluctuations. This self-loosening phenomenon poses a considerable challenge to the reliability of bolted connections, necessitating regular inspections to ensure their safety.
View Article and Find Full Text PDFBMC Geriatr
January 2025
Department of Neurosurgery, Yonsei University College of Medicine, 50, Yonsei-Ro, Seodaemun-Gu, Seoul, 03722, Republic of Korea.
Background: Comparative studies of posterior lumbar interbody fusion with cortical bone trajectory and pedicle screw in older patients, particularly in those aged ≥ 80 years, are rare. This study aimed to retrospectively analyze the clinical and surgical outcomes following posterior lumbar interbody fusion with pedicle screw fixation compared to cortical bone trajectory in patients aged ≥ 80 years with degenerative lumbar spine disease.
Methods: We included 68 patients aged ≥ 80 years who underwent degenerative lumbar spinal surgery at our spine center between January 2011 and December 2020.
Neuromodulation
January 2025
Division of Gastroenterology and Hepatology, University of Michigan School of Medicine, Ann Arbor, MI, USA. Electronic address:
Objectives: Gastrointestinal (GI) disturbance is a frequent complication in patients with thoracolumbar vertebral fracture (TVF). Transcutaneous electrical acustimulation (TEA) has been reported to effectively accelerate postoperative GI function recovery after abdominal surgery. This study aimed to investigate the effects of TEA on postoperative recovery and the associated mechanisms.
View Article and Find Full Text PDFJ Int Soc Respir Prot
August 2024
Georgia Institute of Technology, School of Materials Science and Engineering, Atlanta GA USA.
Filtering facepiece respirators (FFRs) are manufactured in discrete sizes, with some models being limited in relation to accommodating the fit of some sex and race combinations. This study presents the development of a custom-fit respiratory protective device (RPD) which conforms to a user's facial features and flexes and moves with facial movements during use. Our design also integrates a pressure-sensing network, which continuously monitors fit and will alert the user when the fit is compromised.
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