To evaluate the length and orientation of masseter in different types of malocclusions using Cone Beam Computed Tomography (CBCT).
Samples of 180 patients seeking orthodontic treatment at the ...University of Nevada, Las Vegas School of Dentistry, were included in the study. Pre-treatment multi-slice CBCT scans of these patients were divided into three anteroposterior groups: Class I subjects with ANB angle 0° to 5°; Class II subjects with ANB angle >5°; and Class III subjects with ANB angle <0°. CBCT scans were also divided into three vertical groups: normodivergent subjects with mandibular plane angle 22° to 30°; hyperdivergent subjects with mandibular plane angle >30°, hypodivergent subjects with mandibular plane angle <22°. The masseter was identified and landmarks were placed on the anterior border, at the origin and insertion of the muscle in 3-D mode of the Dolphin Imaging 10.5 Premium software. The Frankfort Horizontal Plane was used as a reference plane and an angular measurement was obtained by intersection of a line produced by the masseter landmarks to calculate the orientation of the muscles. The length of the masseter was measured and data were analyzed using ANOVA and matched pairs test.
ANOVA found significant differences in muscle length among the three vertical groups for both the left and right muscles. Paired t test showed significantly shorter muscle length for the hypodivergent group (43.3 ± 4.0 mm) compared to the normodivergent group (45.6 ± 4.5 mm, P < 0.05) and shorter muscle length for the hyperdivergent group (42.3 ± 4.7 mm) compared to the hypodivergent group, P < 0.05. No significant differences were found in muscle length among the three anteroposterior groups. However, significant differences in muscle orientation angle were found among the three anteroposterior groups (P < 0.05). Class II subjects were found to have the most acute orientation angle (67.2 ± 6.6°) and Class III had the most obtuse orientation angle (81.6 ± 6.8°).
These results suggest that certain types of malocclusion may have different masseter lengths and orientations and these differences may have implications for the mechanical advantage in bite force. For example, Class III individuals may have greater bite force than Class II individuals because the muscle fibers are oriented more along the arch of closure.
Signal shapes in multiwire proportional chamber-based TPCs Windelband, J. Alme T. Alt H. Appelshäuser M. Arslandok R. Averbeck E. Bartsch P. Becht L. Bratrud P. Braun-Munzinger H. Buesching H. Caines P. Christiansen F. Costa U. Frankenfeld J. J. Gaardhøje C. Garabatos P. Glässel T. Gunji H. Hamagaki J. W. Harris E. Hellbär H. Helstrup M. Ivanov J. Jung M. Jung A. Junique A. Kalweit R. Keidel S. Kirsch M. Kleiner M. Kowalski M. Krüger C. Lippmann M. Mager S. Masciocchi A. Matyja D. Miśkowiec R. H. Munzer L. Musa B. S. Nielsen J. Otwinowski M. Pikna A. Rehman R. Renfordt D. Röhrich H. S. Scheid C. Schmidt H. R. Schmidt K. Schweda Y. Sekiguchi D. Silvermyr B. Sitar J. Stachel K. Ullaland R. Veenhof V. Vislavicius J. Wiechula B
arXiv.org,
12/2023
Paper, Journal Article
Odprti dostop
A large-volume Time Projection Chamber (TPC) is the main tracking and particle identification (PID) detector of the ALICE experiment at the CERN LHC. PID in the TPC is performed via specific ...energy-loss measurements (dE/dx), which are derived from the average pulse-height distribution of ionization generated by charged-particle tracks traversing the TPC volume. During Runs 1 and 2, until 2018, the gas amplification stage was based on multiwire proportional chambers (MWPC). Signals from the MWPC show characteristic long negative tails after an initial positive peak due to the long ion drift times in the MWPC amplification region. This so-called ion tail can lead to a significant amplitude loss in subsequently measured signals, especially in the high-multiplicity environment of high-energy Pb-Pb collisions, which results in a degradation of the dE/dx resolution. A detailed study of the signal shapes measured with the ALICE TPC with the Ne-CO2 (90-10) and Ar-CO2 (90-10) gas mixtures is presented, and the results are compared with three-dimensional Garfield simulations. The impact of the ion tail on the PID performance is studied employing the ALICE simulation framework and the feasibility of an offline correction procedure to account for the ion tail is demonstrated.
This paper presents the design of a front-end circuit for monolithic active pixel sensors. The circuit operates with a sensor featuring a small, low-capacitance (< 2 fF) collection electrode and is ...integrated in the DPTS chip, a proof-of-principle prototype of 1.5 mm × 1.5 mm including a matrix of 32 × 32 pixels with a pitch of 15 μm. The chip is implemented in the 65 nm imaging technology from the Tower Partners Semiconductor Co. foundry and was developed in the framework of the EP-R&D program at CERN to explore this technology for particle detection. The front-end circuit has an area of 42 μm 2 and can operate with a power consumption as low as 12 nW. Measurements on the prototype relevant to the front-end will be shown to support its design.
The measurement of the production of charm jets, identified by the presence of a D$^{0}$ meson in the jet constituents, is presented in proton–proton collisions at centre-of-mass energies of $ ...\sqrt{s} $ = 5.02 and 13 TeV with the ALICE detector at the CERN LHC. The D$^{0}$ mesons were reconstructed from their hadronic decay D$^{0}$ → K$^{−}$π$^{+}$ and the respective charge conjugate. Jets were reconstructed from D$^{0}$-meson candidates and charged particles using the anti-k$_{T}$ algorithm, in the jet transverse momentum range 5 < p$_{T,chjet}$< 50 GeV/c, pseudorapidity |η$_{jet}$| < 0.9 − R, and with the jet resolution parameters R = 0.2, 0.4, 0.6. The distribution of the jet momentum fraction carried by a D$^{0}$ meson along the jet axis $ \left({z}_{\Big\Vert}^{\textrm{ch}}\right) $ was measured in the range 0.4 <$ {z}_{\Big\Vert}^{\textrm{ch}} $< 1.0 in four ranges of the jet transverse momentum. Comparisons of results for different collision energies and jet resolution parameters are also presented. The measurements are compared to predictions from Monte Carlo event generators based on leading-order and next-to-leading-order perturbative quantum chromodynamics calculations. A generally good description of the main features of the data is obtained in spite of a few discrepancies at low p$_{T,chjet}$. Measurements were also done for R = 0.3 at $ \sqrt{s} $ = 5.02 and are shown along with their comparisons to theoretical predictions in an appendix to this paper.graphic not available: see fulltext
Landscape perspective on energy forests Skärbäck, Erik; Becht, Peter
Biomass & bioenergy,
02/2005, Letnik:
28, Številka:
2
Journal Article, Conference Proceeding
Recenzirano
In 1982–1983, a 70
ha energy forest project was established in an arable landscape in southern Sweden. Many aspects of the energy forest system were investigated. This paper reports mainly on the ...aesthetic impacts of the project at a landscape level. One effect is an increasing variation in the views and the aesthetic values of the arable land. The Salix crops introduce new colours into the arable landscape. The green colour of the Salix fields lasts longer in the autumn. Also, from year to year a spatial variation appears. The increasing wildlife shelter seems to make the fauna richer. Viewed as an energy crop only, the commercial competitiveness of energy forests is often low. However, if the benefits of energy crops as elements of the landscape are added, the socio–economic value could be substantial. Such landscape benefits include increasing biodiversity in the arable landscape, wind-shelter against soil erosion and snow, shelter for wildlife, the reduction of nitrogen leaching, views of the landscape and aesthetic considerations, and recovery of the organic soil component of arable land. An interesting question is whether or not energy forests grown on arable land are profitable from a socio–economic point of view when considering a more holistic evaluation of all the largely beneficial impacts of energy forests.
Objectives. To evaluate the masseter muscle, in both orientation and length, in the anterior-posterior and vertical dimension using 3D Cone Beam Computed Tomography. Methods. One hundred and eighty ...two DICOM files were analyzed using Dolphin imaging 10.5 Premium licensed to West Virginia School of Dentistry Department of Orthodontics. These DICOM file were divided into anterior-posterior groups using ANB angle. The groups were Group I determined to be subjects with normal skeletal growth pattern, Class I ANB angle range 0°–5°, Class II ANB angle > 5°, and Class III ANB angle < 0°. Overjet will be recorded for all subjects groups. The DICOM files were also divided into vertical groups consisting of normodivergent with mandibular plane angle (FH/MP 22° to 30°), and hyperdivergent with mandibular plane angle > 30°, hypodivergent with mandibular plane angle < 22°. The masseter muscle was identified and landmarks placed on the anterior border, at the origin and insertion of the muscle, in 3D mode of the Dolphin software. The Frankfort Horizontal Plane was used as a reference plane and an angular measurement was obtained with intersection of a line produced by the masseter muscle landmarks, thus calculating the orientation of the masseter muscle. The length of the masseter muscle was also calculated in millimeters using the landmarks. Results. The right and left masseter muscle length and orientation was compared for all subjects in this study (n=182) using ANOVA and matched pairs test and no significance was found. The masseter muscle length was determined to be not significant in the anterior-posterior dimension but statistical significance was seen in the vertical dimension between hyperdivergent and hypodivergent groups and hypodivergent and normodivergent groups. The masseter muscle orientation angle was determined to be not significant in the vertical dimension but significant in the anterior-posterior dimension between the Class I, Class II, and Class III groups. Conclusions. The masseter muscle orientation angle is statistically significant in the anterior-posterior dimension with Class II having the most acute orientation angle and Class III having the most obtuse orientation angle. This shows that there is a mechanical advantage in bite force for Class III individuals versus Class II individuals mainly because muscle fibers are oriented more along the arch of closure enabling these individual to produce more force in biting. Other studies should be done to determine if the orientation of the masseter muscle changes after orthognathic surgery is completed and if this effects stability.
Thesis (M.S.)--West Virginia University, 2009.
Title from document title page. Document formatted into pages; contains viii, 88 p. : ill. (some col.). Vita. Includes abstract. Includes ...bibliographical references (p. 62-66).
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