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Journal articles on the topic 'Jaws Jaws'

Author: Grafiati

Published: 4 June 2021

Last updated: 16 February 2022

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1

Bergman, C. F. "Reversal in some fossil polychaete jaws." Journal of Paleontology 72, no. 4 (July 1998): 632–38. http://dx.doi.org/10.1017/s002233600004035x.

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Scolecodonts, the jaws of polychaetes, are the fossil evidence of the rich and diverse fauna that prospered in shelf seas. Among eunicid polychaetes, the largest jaws in the jaw apparatus occur in pairs. Normally these pairs are not exact mirror images of each other. Rarely, left and right jaws are found to be reversed, the jaw in the left position having the morphology of a mirror image of the normal right jaw and vice-versa. This type of morphological reversal (reversed handedness) is recorded with a frequency that varies from one reversed jaw in 430 to one in 5,838 of normal jaws. Reversed jaws so far are documented in four species from the Upper Ordovician of Indiana, USA, and one species from the Silurian of Gotland, Sweden. The reversed morphology is thought to be a natural, genetically induced feature. The polychaetes with morphological reversal grew to normal size, but never became common.

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2

Greaves, Walter Stalker. "Modeling the distance between the molar tooth rows in mammals." Canadian Journal of Zoology 80, no. 2 (February 1, 2002): 388–93. http://dx.doi.org/10.1139/z02-008.

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The sum of all possible bite forces along a mammalian tooth row is related to the area under the curve when bite force is plotted from one end of the tooth row to the other. Integrating the equation of this plot and dividing by the length of the entire jaw, from joint to incisor, gives the average bite force along the entire jaw (as opposed to along the tooth row). Calculations indicate that for any jaw shape there is only one location for the tooth row relative to the midline of the skull, where the average bite force is maximized; the average force is lower when the tooth row is closer to, or farther from, the midline. In addition, for animals with long narrow jaws, the location where this maximum is realized is relatively closer to the midline than it is for animals with short wide jaws. In many mammals, the distance between the jaw joints (jaw width) often varies between 60 and 80% of the distance from the jaw joints to the incisor (jaw length) in narrow and wide jaws, respectively. Length is measured perpendicular to the resultant force of the jaw muscles. Accepting that average bite force will be maximized, the model predicts that in the longer, narrower jaws the distance between the two molar rows will be approximately half the width of the jaw (and will approach 60% in the shorter, wider jaws).

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3

Purnell, B. A. "Jaws." Science 330, no. 6002 (October 14, 2010): 297. http://dx.doi.org/10.1126/science.330.6002.297-a.

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4

Berry, C. "Jaws." QJM 97, no. 9 (August 18, 2004): 633–34. http://dx.doi.org/10.1093/qjmed/hch103.

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5

Larson, Neal L., and Neil H. Landman. "Description of the lower jaws of Baculites from the Upper Cretaceous U.S. Western Interior." Acta Geologica Polonica 67, no. 1 (March 1, 2017): 109–20. http://dx.doi.org/10.1515/agp-2017-0006.

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Abstract We report the discovery of lower jaws of Baculites (Ammonoidea) from the Upper Cretaceous U.S. Western Interior. In the lower Campanian Smoky Hill Chalk Member of the Niobrara Chalk of Kansas, most of the jaws occur as isolated elements. Based on their age, they probably belong to Baculites sp. (smooth). They conform to the description of rugaptychus, and are ornamented with coarse rugae on their ventral side. One specimen is preserved inside a small fecal pellet that was probably produced by a fish. Another specimen occurs inside in a crushed body chamber near the aperture and is probably in situ. Three small structures are present immediately behind the jaw and may represent the remains of the gills. In the lower Maastrichtian Pierre Shale of Wyoming, two specimens of Baculites grandis contain lower jaws inside their body chambers, and are probably in situ. In both specimens, the jaws are oriented at an acute angle to the long axis of the shell, with their anterior ends pointing toward the dorsum. One of the jaws is folded into a U-shape, which probably approximates the shape of the jaw during life. Based on the measurements of the jaws and the shape of the shell, the jaws could not have touched the sides of the shell even if they were splayed out, implying that they could not have effectively served as opercula. Instead, in combination with the upper jaws and radula, they constituted the buccal apparatus that collected and conveyed food to the esophagus.

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6

Ngeow, W. C. "Irradiated jaws." British Dental Journal 198, no. 11 (June 2005): 698–99. http://dx.doi.org/10.1038/sj.bdj.4812446.

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7

Kamboj, M. "Phossy jaws." British Dental Journal 203, no. 10 (November 2007): 559. http://dx.doi.org/10.1038/bdj.2007.1057.

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8

Martin, Jennifer A. "Seeing Jaws." Historical Studies in the Natural Sciences 46, no. 1 (February 1, 2016): 67–100. http://dx.doi.org/10.1525/hsns.2016.46.1.67.

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Few scientists played a greater role in constructing how Americans envisioned sharks than marine biologist Perry W. Gilbert. From the 1940s to the 1980s, he and a handful of other scientists linked earlier investigations of morphology with newer studies on populations and ecosystem dynamics to understand predation in marine environments. Investigators often abstracted sharks by privileging body parts, such as the jaws or eyes, in ways that made it difficult to see this group of animals within larger ecological or historical contexts. Starting in the 1960s, shark tagging studies helped convince a growing number of researchers that these creatures were vulnerable to overexploitation.

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9

Oravcova, Jarmila. "The Methodical Procedure for Designing of Clamping Jaws." Applied Mechanics and Materials 693 (December 2014): 44–49. http://dx.doi.org/10.4028/www.scientific.net/amm.693.44.

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The paper deals with the clamping fixture jaws procedure design. The clamping jaw design methodology developed summarizes complex factors. These factors affect the clamping jaws design for the workpiece. Methodical design procedure consists of three stages. Namely, there are input date summary, clamping fixture design and the last design verification. The ANSYS simulation was used for the verification developing methodology. The components model simulation aim has been studied impact of clamping force position change to the cutting force reactions change. Research was conducted with different positions of jaws.

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10

Andrew, David. "Radiopacities of the Jaws: Interpretation and Diagnosis." Primary Dental Journal 7, no. 1 (March 2018): 31–37. http://dx.doi.org/10.1308/205016818822610299.

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General dental practitioners are less confident at diagnosing radiopaque lesions of the jaws than radiolucent ones, possibly because the incidence of jaw radiopacities is comparatively low. The current review covers the majority of radiopaque lesions that are referred for a specialist opinion, and focuses on those lesions that occur commonly or those that mimic other diagnoses. The majority of radiopaque jaw lesions represent normal anatomy/normal variants or superimposed soft tissue calcifications that are typically of no clinical significance. Common pathological radiopacities of the jaws include sclerosing (condensing) osteitis, a response to low-grade chronic apical infection, and odontomes, a form of odontogenic hamartoma. The typical imaging appearances of these and other jaw radiopacities are discussed.

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11

Arzhantsev, A. P. "X-RAY MANIFESTATIONS OF OSTEOMYELITIS JAWS." Russian Electronic Journal of Radiology 11, no. 1 (2021): 28–42. http://dx.doi.org/10.21569/2222-7415-2021-11-1-28-42.

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Among purulent-necrotic processes in the jaws, odontogenic osteomyelitis occurs in most cases in comparison with posttraumatic and hematogenic osteomyelitis. A separate group of jaw lesions consists of radiation, bisphosphonate and phosphoric necrosis, which at the stage of joining the inflammation have x-ray manifestations of the osteomyelitic process. X-ray semiotics of osteomyelitis of the jaws is diverse. X-ray features of osteomyelitis depend on the etiology, stage of course and form of the bone inflammatory process. X-ray diagnosis of osteomyelitis should be carried out taking into account the history of the disease and identifying factors that contribute to their development. Since orthopantomography does not provide comprehensive information about the state of the dental system, this technique can be considered as a method of primary detection of osteomyelitis of the jaws. At the next stage of diagnosis, it is advisable to use a CT scan, especially for lesions of the upper jaw with spread to other facial bones.

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12

Postic, Srdjan. "Surface area analysis in edentulous jaws of patients with skeletal class I." Serbian Dental Journal 58, no. 4 (2011): 209–15. http://dx.doi.org/10.2298/sgs1104209p.

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Introduction. The surface area of edentulous jaw has been considered as an important functional and anthropometric parameter. The aim of this study was to assess the surface area of supporting tissue in edentulous jaws of patients with the skeletal class I. Material and Methods. Thin aluminum foils (0.5 mm of thickness) were adapted on plaster surfaces of 139 pairs of edentulous jaws casts. Foils were positioned on a millimeter-paper in order to measure their areas. Additionally, surface areas were measured using a mechanic plan-meter (G. Coradi, Zurich, Switzerland, serial no. 49823). The measurement error was 1%. Skeletal class of edentulous jaws was determined by analysis of lateral cephalometric radiographs, and assessing the ANB (SNA, SNB) angle. Results. The average surface area of edentulous upper jaws was 4654?407 mm2 in males, and 4212?368 mm2 in females. Edentulous lower jaws had average surface area of 2843?339 mm2 in males, and 2334?295 mm2 in females. Statistically significant difference (p<0.001) was found in comparison of surface areas and dimensions of upper and lower edentulous jaws in male and female. ANB values ranged from 2 to 4 degrees. Conclusion. The surface area is an important parameter in the analysis of edentulous jaws. Edentulous jaws in males had greater surface areas and dimensions as compared to females. Edentulous areas on the right side were not absolutely symmetric to areas on the left side.

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13

Abbas Zaidi, Nayyer, and Shafaat Ahmed Bazaz. "Development of a reliable microgripper system based on failure analysis." Industrial Robot: An International Journal 41, no. 3 (May 13, 2014): 318–26. http://dx.doi.org/10.1108/ir-04-2014-0322.

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Purpose – The purpose of this paper is to present the design of a microgripper system that comprises a dual jaw actuation mechanism with contact sensing. Design/methodology/approach – Interdigitated lateral comb-drive-based electrostatic actuator is used to move the gripper arms. Simultaneous contact sensing of the gripper jaws has been achieved through transverse comb-based capacitive sensor. The fabricated microgripper produces a displacement of 16 μm at gripper jaws for an applied actuation voltage of 45 V. Findings – It is observed that the microgripper fails to operate for the maximum performance limits (70 μm jaws displacement) and produces uncontrolled force at the tip of the jaws > 45 V. Originality/value – A novel behavioral model of the microgripper system is proposed using the fabricated dimensions of the system to carry out a detailed analysis to understand the cause of this failure. The failure analysis shows that the microgripper system failed to operate in its designed limits due to the presence of side instability in the designed combs structure. Our proposed failure model helps in redesigning the actuator to ensure its operation above 45 V so that the gripper jaw can be displaced to its maximum limit of 70 μm and also result in the increase of the controlled force from 250 to 303 μN at the microgripper jaws.

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14

Currie, Philip J., Stephen J. Godfrey, and Lev Nessov. "New caenagnathid (Dinosauria: Theropoda) specimens from the Upper Cretaceous of North America and Asia." Canadian Journal of Earth Sciences 30, no. 10 (October 1, 1993): 2255–72. http://dx.doi.org/10.1139/e93-196.

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New specimens of caenagnathid theropods are described from the Judith River Formation (Campanian) of southern Alberta, the Hell Creek Formation (Maastrichtian) of South Dakota, and the Bissekty Formation (Turonian) of Uzbekistan. With the exception of the Hell Creek specimen, and a vertebra from Alberta, all are from the symphysial regions of the lower jaws. Caenagnathids are rare and poorly known animals, and the described fossils preserve heretofore unknown features, including vascular grooves and foramina in the symphysial region, and the pattern of overlapping sutures between jaw elements. Most of the new specimens are different from the holotype of Caenagnathus collinsi Sternberg and may represent the second described species, Caenagnathus sternbergi. The two jaws from the Bissekty Formation are the first oviraptorosaurian jaws described from Uzbekistan and represent a new genus and species anatomically closer to Caenagnathus than to central Asian forms like Oviraptor, Conchoraptor and Ingenia. There are at least five characters that distinguish caenagnathid and oviraptorid jaws, but it is concluded that the length of the symphysial region must be used with caution. Jaw anatomy supports the idea that oviraptorids were well adapted for eating eggs, although their diet was probably not restricted to one food type.

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15

Pămîntaş, Eugen, and Felicia Veronica Banciu. "Looking for a Mathematical Solution for a Self-Centering Device." Applied Mechanics and Materials 657 (October 2014): 509–13. http://dx.doi.org/10.4028/www.scientific.net/amm.657.509.

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Proper centering problem is common to processing by cutting the metal or nonmetallic cylindrical parts. This paper proposes a solution useful in self-centering devices with mobile jaws, both in terms of cinematic jaw movement - rotation instead of translation - as well as the active profile of the jaw - curvilinear instead of straight. The method of problem solving is mathematical deduction, on the one hand by establishing the geometrical calculus schemes that describes the graphic curves for the envelope of a single-sided curvilinear profile for jaw, and on the other by the generalization of the solution for the case the active surfaces of the jaws are both curvilinear profile.

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16

Ko, Daisy (Jihyung), Tess Kelly, Lacey Thompson, Jasmene K. Uppal, Nasim Rostampour, Mark Adam Webb, Ning Zhu, et al. "Timing of Mouse Molar Formation Is Independent of Jaw Length Including Retromolar Space." Journal of Developmental Biology 9, no. 1 (March 12, 2021): 8. http://dx.doi.org/10.3390/jdb9010008.

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For humans and other mammals to eat effectively, teeth must develop properly inside the jaw. Deciphering craniodental integration is central to explaining the timely formation of permanent molars, including third molars which are often impacted in humans, and to clarifying how teeth and jaws fit, function and evolve together. A factor long-posited to influence molar onset time is the jaw space available for each molar organ to form within. Here, we tested whether each successive molar initiates only after a minimum threshold of space is created via jaw growth. We used synchrotron-based micro-CT scanning to assess developing molars in situ within jaws of C57BL/6J mice aged E10 to P32, encompassing molar onset to emergence. We compared total jaw, retromolar and molar lengths, and molar onset times, between upper and lower jaws. Initiation time and developmental duration were comparable between molar upper and lower counterparts despite shorter, slower-growing retromolar space in the upper jaw, and despite size differences between upper and lower molars. Timing of molar formation appears unmoved by jaw length including space. Conditions within the dental lamina likely influence molar onset much more than surrounding jaw tissues. We theorize that molar initiation is contingent on sufficient surface area for the physical reorganization of dental epithelium and its invagination of underlying mesenchyme.

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17

Tanabe, Kazushige, Yasuyuki Tsujino, Kosuke Okuhira, and Akihiro Misaki. "The jaw apparatus of the Late Cretaceous heteromorph ammonoid Pravitoceras." Journal of Paleontology 89, no. 4 (July 2015): 611–16. http://dx.doi.org/10.1017/jpa.2015.27.

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AbstractWell-preserved upper and lower jaws of the aptychus-type found inside the body chambers of two specimens of the heteromorph ammonoid Pravitoceras sigmoidale Yabe, 1902 (Nostoceratidae, Ancyloceratina) are described from the Upper Cretaceous Izumi Group in Southwest Japan. They are similar in overall morphology to those of other nostoceratid and diplomoceratid ammonoids currently known, suggesting the morphological stability of the jaw features among these taxa. The equal size of the upper and lower jaws with beak-like rostral projection suggests that the jaw apparatus of this species might function to bite and cut up prey.

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18

Zhang, Mike Tao, and Ken Goldberg. "Designing robot grippers: optimal edge contacts for part alignment." Robotica 25, no. 3 (May 2006): 341–49. http://dx.doi.org/10.1017/s0263574706003134.

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SUMMARYAlthough parallel-jaw grippers play a vital role in automated manufacturing, gripper surfaces are still designed by trial-and-error. This paper presents an algorithmic approach to designing gripper jaws that mechanically align parts in the vertical (gravitational) plane. We consider optimal edge contacts, based on modular trapezoidal segments that maximize contact between the gripper and the part at its desired final orientation. Given then-sided 2D projection of an extruded convex polygonal part, mechanical properties such as friction and center of mass, and initial and desired final orientations, we present anO(n3logn) numerical algorithm to design optimal gripper jaws. We also present anO(nlogn) algorithm to compute tolerance classes for these jaws, and report on an online implemented version of the algorithm and physical experiments with the jaws it designed. This paper extends earlier results that generated optimal point contacts [M. T. Zhang and K. Goldberg, “Gripper point contacts for part alignment,”IEEE Trans. Robot. Autom.18(6), 902–910 (2002)].

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19

O'Luanaigh, Cian. "Jaws, Cretaceous-style: how jaw bones became tiny earbones." New Scientist 210, no. 2808 (April 2011): 16. http://dx.doi.org/10.1016/s0262-4079(11)60839-7.

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20

Fransen, J. A. M., K. V. Kardong, and P. Dullemeijer. "Feeding Mechanism in the Rattlesnake Crotalus durissus." Amphibia-Reptilia 7, no. 3 (1986): 271–302. http://dx.doi.org/10.1163/156853886x00055.

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AbstractCineradiography and electromyography were used to study the strike and swallowing behaviour of the rattlesnake, Crotalus durissus. From the data gathered, we describe the kinetic events of the cranial bones correlated with both the activity of individual jaw muscles (electromyograms) and with the calculated relative forces produced by these same muscles. During the strike, the independently suspended jaws of left and right sides simultaneously protract to erect the folded fangs. This is accompanied by opening of the lower jaws. Some low level activity first appears in the depressor muscles, but immediately thereafter they and all other jaw muscles suddenly and nearly simultaneously reach peak output. From the calculated relative muscle forces, vector models of the jaws were determined for early and peak points in the strike. Swallowing is accomplished by reciprocating alternate motions of bones on the left and right sides of the skull. This produces a swallowing cycle of two phases, moving and fixing. In turn, each phase divides into three parts-opening, advance, close. On the ipsilateral side, opening is characterized by a relaxation of contact of bones and teeth they bear with the prey and the braincase begins rotation about three axes simultaneously. Motions begun in opening, contiue into advance, but now the ipsilateral jaw elements are protracted to progress them along the prey. As protraction ends, the jaws again come into contact with the prey to establish the close part of the moving phase of swallowing. After a pause, the fixing phase begins while opposite jaw elements now take their turn to progress through similar displacements. During this fixing phase ipsilateral elements arc often further retracted. Emphasis is given to the complicated rotations of the braincase which contribute first to disengagement of teeth and second to advancement of suspended jaw elements around and along the prey. Most muscles reached peak output during one of the two swallowing phases, although the timing and intensity of these peaks varied between muscles. The relative muscle forces were used to construct vector models of the jaws during stages of swallowing. Upon these vector models and from the overall patterns of activity, determination was made of the likely roles played by individual muscles in abduction, protraction, and adduction of jaw elements. Muscles, besides being basic movers of the jaw elements, apparently also play critical parts in stabilizing and regulating the controlled positioning of bones.

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21

Edwards, David. "Jaws of Life." Iowa Review 17, no. 2 (April 1987): 139–54. http://dx.doi.org/10.17077/0021-065x.3531.

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22

Chaudhary, Mayur, and ShwetaDixit Chaudhary. "Osteosarcoma of jaws." Journal of Oral and Maxillofacial Pathology 16, no. 2 (2012): 233. http://dx.doi.org/10.4103/0973-029x.99075.

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23

Mueck, Leonie. "Jaws up close." Nature Chemistry 6, no. 3 (February 20, 2014): 169. http://dx.doi.org/10.1038/nchem.1883.

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24

Long, John A. "The first jaws." Science 354, no. 6310 (October 20, 2016): 280–81. http://dx.doi.org/10.1126/science.aai8828.

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25

Mitchell, Alison. "Jaws of death." Nature Reviews Molecular Cell Biology 2, no. 8 (August 2001): 561. http://dx.doi.org/10.1038/35085047.

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26

Vignieri, Sacha. "Teeth and jaws." Science 369, no. 6500 (July 9, 2020): 154.1–154. http://dx.doi.org/10.1126/science.369.6500.154-a.

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27

Gee, Henry. "Jaws with claws." Nature 363, no. 6431 (June 1993): 681. http://dx.doi.org/10.1038/363681a0.

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28

Fudge, D. "JAWS OF LIFE." Journal of Experimental Biology 209, no. 5 (March 1, 2006): v—vi. http://dx.doi.org/10.1242/jeb.02098.

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29

Zhang, Hal Y. "Jurassic Jaws Jones." Nature 546, no. 7660 (June 2017): 696. http://dx.doi.org/10.1038/546696a.

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30

Santana, N., S. Mehazabin, K. Sangeetha, and M. Kumari. "Osteodystrophies of jaws." Journal of Oral and Maxillofacial Pathology 24, no. 2 (2020): 405. http://dx.doi.org/10.4103/jomfp.jomfp_225_19.

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31

Holzman, Roi, Steven W. Day, Rita S. Mehta, and Peter C. Wainwright. "Jaw protrusion enhances forces exerted on prey by suction feeding fishes." Journal of The Royal Society Interface 5, no. 29 (June 10, 2008): 1445–57. http://dx.doi.org/10.1098/rsif.2008.0159.

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The ability to protrude the jaws during prey capture is a hallmark of teleost fishes, widely recognized as one of the most significant innovations in their diverse and mechanically complex skull. An elaborated jaw protrusion mechanism has independently evolved multiple times in bony fishes, and is a conspicuous feature in several of their most spectacular radiations, ultimately being found in about half of the approximately 30 000 living species. Variation in jaw protrusion distance and speed is thought to have facilitated the remarkable trophic diversity found across fish groups, although the mechanical consequences of jaw protrusion for aquatic feeding performance remain unclear. Using a hydrodynamic approach, we show that rapid protrusion of the jaws towards the prey, coupled with the spatial pattern of the flow in front of the mouth, accelerates the water around the prey. Jaw protrusion provides an independent source of acceleration from that induced by the unsteady flow at the mouth aperture, increasing by up to 35% the total force exerted on attached, escaping and free-floating passive prey. Despite initiating the strike further away, fishes can increase peak force on their prey by protruding their jaws towards it, compared with a ‘non-protruding’ state, where the distance to prey remains constant throughout the strike. The force requirements for capturing aquatic prey might have served as a selective factor for the evolution of jaw protrusion in modern fishes.

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32

Tanabe, Kazushige, Pat Trask, Rick Ross, and Yoshinori Hikida. "Late Cretaceous octobrachiate coleoid lower jaws from the north Pacific regions." Journal of Paleontology 82, no. 2 (March 2008): 398–408. http://dx.doi.org/10.1666/07-029.1.

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Eight well-preserved cephalopod jaw fossils were discovered from the Upper Cretaceous (Santonian and Campanian) deposits of Vancouver Island, Canada, and Hokkaido, Japan. They occur individually in calcareous concretions and retain their three-dimensional architecture. Seven of them consist of a widely open outer lamella and a posteriorly projected inner lamella with a pointed rostrum. Both lamellae are made of fluorapatite, which may represent diagenetically altered chitin, and lack a calcareous element. Based on these diagnostic features, the seven jaw fossils are identified as lower jaws of the Coleoidea. Comparison with the lower jaws of modern coleoids allows us to distinguish the following new genera and species among them;Nanaimoteuthis jeletzkyiof the Order Vampyromorphida, andPaleocirroteuthis haggartiandP. pacificaof the Order Cirroctopodida. The lower jaws of these new taxa are clearly distinguished by having a much less projected inner lamella from those of modern and extinct species of the Superorder Decabrachia and the Order Octopodida. The maximum lengths of their outer lamellae (35.0-67.1 mm) are much larger than those of most modern vampyromorph and cirroctopodid species, indicating the large body size and weight of their owners. One of the other three lower jaws examined, characterized by a posteriorly extended outer lamella, may be assigned to the Octopodida. This study clearly demonstrates that large octobrachiate coleoids existed in the Late Cretaceous North Pacific.

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33

Vandewalle, P., M. Havard, G. Claes, and F. De Vree. "Mouvements des mâchoires pharyngiennes pendant la prise de nourriture chez le Serranus scriba (Linné, 1758) (Pisces, Serranidae)." Canadian Journal of Zoology 70, no. 1 (January 1, 1992): 145–60. http://dx.doi.org/10.1139/z92-022.

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According to the morphology of its pharyngeal jaw apparatus, Serranus scriba can be considered as an intermediate type within the Acanthopterygians. The lower jaws are united only at their fore end. The upper pharyngeal jaws do not articulate with the skull base. Each of them consists of pharyngobranchials 2 and 3 (the latter being well developed), bearing a tooth plate, and of one posterior tooth plate, associated with two smaller tooth plates supported by epibranchials 2 and 3. The branchial musculature is of a generalized perciform type. Muscle activity generates variable cyclic movements of the pharyngeal jaws for transporting prey from the buccal cavity to the oesophagus, in cases where the prey is provided with a shell or a cuticle. Masticatory movements are not stereotyped as in more specialized fishes such as Labridae. Prey transport is more efficient when the upper and lower pharyngeal jaws retract together, either in complete synchrony or with a phase shift. This is often accompanied by downward movements of the upper jaws. The amplitude of movements of the components of the upper pharyngeal jaw may vary within one cycle. For instance, pharyngobranchial 2 could be drawn more forward, while pharyngobranchial 3 could be drawn more backward and the posterior tooth plate could move up and down independently. These movements can be induced passively by the interactions with the prey and (or) eventually by specific muscular activity as well. Stereotyped movements of other species probably allow them to meet only the requirements of a specialized diet. In contrast, the flexibility of this movement pattern allows S. scriba to explore a wider range of food types.

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34

Mazur, Marcin. "Determination of crushing energy during vibratory crushing." New Trends in Production Engineering 2, no. 1 (October 1, 2019): 287–94. http://dx.doi.org/10.2478/ntpe-2019-0030.

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Abstract The paper presents a new method of determining the energy consumption for vibratory crushing. Using the laboratory vibratory jaw crusher with kinematic actuation of the jaws, the study of determining power consumption while crushing limestone and diabase was conducted. During the study, electrical energy used on the crushing process was measured as a function of changing design and kinematic parameters of the vibratory crusher, i.e.: jaws stroke, the outlet gap size and frequency of jaws vibration. The article presents program of the research, the laboratory test stand of the vibratory jaw crusher KW 40/1 and the test results. Comparing the theoretical crushing energy requirements, determined by the Bond hypothesis, with the values measured during tests a large differences were observed. Using the Bond hypothesis the Vibratory Work Indexes were determined for the tested materials. Their values are higher than limestone and diabase Work Indexes available in the known literatures. The explanation may be greater amount of energy transferred to the material during vibratory crushing, which results in much higher efficiency of the crushing process.

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35

Pham, D. T., and M. J. Nategh. "Optimum design of gripper jaws for tapered components." Robotica 8, no. 3 (July 1990): 223–30. http://dx.doi.org/10.1017/s0263574700000084.

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SUMMARYFor ease of manufacture, axisymmetric components produced by processes such as forging, casting and moulding are often designed with a taper angle. This paper presents a family of devices for handling such components by their tapered portion. The devices are essentially finger tips, or jaws, to be fitted to standard scissor-type robot grippers. The jaws possess a three-dimensional profile constructed as a stack of v-shaped planar curves. The special jaw profile enables components of different diameters and taper angles to be gripped concentrically without calling for complex movements to reposition the gripper. The equations describing two categories of profile are derived and the optimum selection of profile parameters to yield compact jaws to grip components of a wide range of dimensions is discussed in the paper.

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Lugassy, Gilles, and Anatoly Nemets. "Severe Osteomyelitis of the Jaws in Long Term Survivorsmultiple Myeloma Patients Treated with Biphosphonates.A New Clinical Entity." Blood 104, no. 11 (November 16, 2004): 4900. http://dx.doi.org/10.1182/blood.v104.11.4900.4900.

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Abstract Multiple Myeloma is a frequent and usually fatal lymphoproliferative disorder with a median survival of around 30 months.Supportive therapy includes monthly intravenous injections of biphosphonates as prevention, or therapy,of lytic bone disease. We report three cases of Multiple Myeloma patients who developed severe osteomyelitis of the jaws while receiving prolonged biphosphonate therapy.All three patients are very long survivors of Myeloma,being alive 6 to 12 years after diagnosis.They have been treated with biphosphonates for more than 4 years, receiving large doses of Pamidronate(3420 to 4680 mg) and lesser doses of Zoledronate(16 to 72 mg).Jaw infection was unprovoked in wo parients and was cused by dental extraction in the third.Diagnosis of osteomyelitis was confirmed by histology in all three patients, while in two we could demonstrate the presence of Actinomyces.Therapy with hyperbaric oxygen of osteomyelitis refractory to prolonged antibiotherapy, was curative in one patient. To the best of our knowledge, these are the first cases of osteomyelitis of the jaw reported in the literature in Myeloma patients treated with chronic administration of intravenous biphosphonates.Recent reports have alerted physicians of a ’’ growing epidemics’’ of Pamidronate and Zoledronate induced avascular necrosis of the jaw, most of them provoked by teeth removal.Both of these biphosphonates have strong antiosteoclastic activity, and Zoledronate is antiangeogenic, all properties which contribute to the development of bone necrosis.Since the jaws are the only bones in the skeleton exposed to the external environment, the association of bone necrosis with secondary chronic infections may lead to osteomyelitis.Even though it is not possible to prove beyond doubt an etiological link between biphosphonate therapy and the occurrence of osteomyelitis of the jaws, the association of Myeloma with severe immunosupression, the very prolonged biphosphonate therapy in our three patients, and the localization to the jaw, are in favor of a clear relationship between therapy with Zolandronate, Pamidronate and osteomyelitis of the jaws. With the expected life prolongation of Myeloma patients due to recent therapeutic breakthroughs and the increasing use of antiangeogenic agents, it is crucial to be aware of the possibility of a rise in the number of osteomyelitis of the jaws in Myeloma patients.

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Muthuraman, Varun, and Soundarya Srinivasan. "Familial Case of Cherubism from South India: Differential Diagnosis and Report of 2 Cases." Case Reports in Dentistry 2014 (2014): 1–3. http://dx.doi.org/10.1155/2014/869783.

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Cherubism is a rare familial multilocular cystic lesion of the jaws. The condition clinically appears as a bilateral symmetric swelling of the cheeks in children and is the primary reason for referral. It is a rare lesion of the jaws that has a dominant pattern of inheritance. We report two cases of cherubism, that of a boy and his mother suggestive of a strong familial incidence. A variety of lesions of the jaw mimic this condition and hence the differential diagnosis has been emphasised.

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Goyens, Jana, Joris Dirckx, Maxim Piessen, and Peter Aerts. "Role of stag beetle jaw bending and torsion in grip on rivals." Journal of The Royal Society Interface 13, no. 114 (January 2016): 20150768. http://dx.doi.org/10.1098/rsif.2015.0768.

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In aggressive battles, the extremely large male stag beetle jaws have to withstand strongly elevated bite forces. We found several adaptations of the male Cyclommatus metallifer jaw morphology for enhanced robustness that conspecific females lack. As a result, males improve their grip on opponents and they maintain their safety factor (5.2–7.2) at the same level as that of females (6.8), despite their strongly elevated bite muscle force (3.9 times stronger). Males have a higher second moment of area and torsion constant than females, owing to an enhanced cross-sectional area and shape. These parameters also increase faster with increasing bending moment towards the jaw base in males than in females. Male jaws are more bending resistant against the bite reaction force than against perpendicular forces (which remain lower in battles). Because of the triangular cross section of the male jaw base, it twists more easily than it bends. This torsional flexibility creates a safety system against overload that, at the same time, secures a firm grip on rivals. We found no structural mechanical function of the large teeth halfway along the male jaws. Therefore, it appears that the main purpose of these teeth is a further improvement of grip on rivals.

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Tanabe, Kazushige, and Royal H. Mapes. "Jaws and radula of the Carboniferous ammonoid Cravenoceras." Journal of Paleontology 69, no. 4 (July 1995): 703–7. http://dx.doi.org/10.1017/s0022336000035228.

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A well-preserved mouth apparatus consisting of jaws and a radula was found in situ within the body chamber of the goniatite Cravenoceras fayettevillae Gordon, 1965 (Neoglyphiocerataceae: Cravenoceratidae), from the middle Chesterian (Upper Mississippian) of Arkansas. Both upper and lower jaws consist of a black material. The lower jaw is characterized by a widely opened larger outer lamella and a shorter inner lamella. The upper jaw is fragmental. The radula is preserved in the anterior portion of the buccal space and comprises a series of tooth elements. Each transverse tooth row consists of seven teeth (a rhachidian and pairs of two lateral and one marginal teeth), with a pair of marginal plates. This arrangement is typical of radulae of other ammonoids of Carboniferous to Cretaceous age, coleoids, and the orthoconic “nautiloid” Michelinoceras (Silurian, Michelinocerida), suggesting a phylogenetic affinity among them.

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Alemzadeh, K., and D. Raabe. "Prototyping artificial jaws for the robotic dental testing simulator." Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine 222, no. 8 (November 1, 2008): 1209–20. http://dx.doi.org/10.1243/09544119jeim402.

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This paper presents a robot periphery prototyped for the six-degrees-of-freedom robotic dental testing simulator, simulating the wear of materials on dental components, such as individual teeth, crowns, bridges, or a full set of teeth. The robot periphery consists of the artificial jaws and compliance module. The jaws have been reverse engineered and represent a human-like mandible and maxilla with artificial teeth. Each clinically fabricated tooth consists of a crown and glass ceramic roots which are connected using resin cement. Normal clinical occlusion of the artificial jaws assembly was emulated by a dental articulator based on ‘Andrew's six keys to occlusion’. The radii of the von Spee curve, the Monson curve, and the Wilson curve were also measured as important jaw characteristic indicators to aid normal occlusion. A compliance module had to be built between the lower jaw and the robot platform to sustain the fluctuating forces that occur during normal chewing in the occlusal contact areas, where these high bite forces are major causes of dental component failure. A strain gauge force transducer has been integrated into the machined lower jaw, underneath the second molars, to measure axial biting forces applied to the posterior teeth. The experiments conducted have shown that the sensor is able to sense small changes in the compression force satisfactorily, when applied perpendicular to the occlusal surfaces of the teeth.

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Kotova, I. V., M. E. Beloshitsky, and V. G. Ignatuk. "BONE CHANGES IN JAWS AS A RESULT OF PRIMARY HYPERPARATHYROIDISM." Tavricheskiy Mediko-Biologicheskiy Vestnik 23, no. 2 (2020): 80–84. http://dx.doi.org/10.37279/2070-8092-2020-23-2-80-84.

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An analysis of bone changes in the jaws caused by primary hyperparathyroidism (PHPT) was performed based on the research and our own studies. Presented are the modern principles for the diagnosis of PHPT in patients undergoing treatment in maxillofacial clinics with recurrent epulids and jaw cysts. Variously expressed tumor jaw lesions were observed in 23 of 751 patients. 19 of them have the lower jaw, and 4 have the upper jaw tumors. Tumorous masses in 15 patients were caused by parathyroid adenoma, in 7 – by hyperplasia, in 1 – by cancer. The only clinical manifestation of hyperparathyroidism in 5 patients was a tumor-like mass of the upper jaw, in 1 – the lower one. Changes in the bone structure of jaws were found in PHPT patients who underwent orthopantomography, x-ray or computed tomography of the skull. In 26 of them, grainy and coarse-grained bone reconstruction was determined, in 9 – diffuse rarefaction of facial bones, in 10 – focal osteoclasia, in 21 – resorption of the closing plates of the dental alveoli, in 19 – subperiosteal resorption of the cortical layer of lower jaw. It was found that almost impossible to differentiate osteoblastoclastoma and hyperparathyroid osteodystrophy on a pathomorphological basis. In case of detected PHPT, first of all, the operation is performed on the parathyroid glands, and then the treatment strategy for jaw epulids is determined.

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Kotova, I. V., M. E. Beloshitsky, and V. G. Ignatuk. "BONE CHANGES IN JAWS AS A RESULT OF PRIMARY HYPERPARATHYROIDISM." Tavricheskiy Mediko-Biologicheskiy Vestnik 23, no. 2 (2020): 80–84. http://dx.doi.org/10.37279/2070-8092-2020-23-2-80-84.

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An analysis of bone changes in the jaws caused by primary hyperparathyroidism (PHPT) was performed based on the research and our own studies. Presented are the modern principles for the diagnosis of PHPT in patients undergoing treatment in maxillofacial clinics with recurrent epulids and jaw cysts. Variously expressed tumor jaw lesions were observed in 23 of 751 patients. 19 of them have the lower jaw, and 4 have the upper jaw tumors. Tumorous masses in 15 patients were caused by parathyroid adenoma, in 7 – by hyperplasia, in 1 – by cancer. The only clinical manifestation of hyperparathyroidism in 5 patients was a tumor-like mass of the upper jaw, in 1 – the lower one. Changes in the bone structure of jaws were found in PHPT patients who underwent orthopantomography, x-ray or computed tomography of the skull. In 26 of them, grainy and coarse-grained bone reconstruction was determined, in 9 – diffuse rarefaction of facial bones, in 10 – focal osteoclasia, in 21 – resorption of the closing plates of the dental alveoli, in 19 – subperiosteal resorption of the cortical layer of lower jaw. It was found that almost impossible to differentiate osteoblastoclastoma and hyperparathyroid osteodystrophy on a pathomorphological basis. In case of detected PHPT, first of all, the operation is performed on the parathyroid glands, and then the treatment strategy for jaw epulids is determined.

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Gaivoronsky, Ivan V., Maria G. Gaivoronskaya, Oksana M. Fandeeva, and Vladimir A. Shashkov. "Typical features of morphometric parameters of the mandible in adults." Курский научно-практический вестник «Человек и его здоровье», no. 2 (June 2020): 34–41. http://dx.doi.org/10.21626/vestnik/2020-2/05.

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Objective: to develop a classification of mandibular forms and to study typical features of the morphometric characteristics of this bone in adults. Materials and methods. The study was conducted on 150 lower jaws of adults. To determine the shape of the lower jaw, four morphometric parameters were measured: angular width, projection length from the corners, branch height, smallest branch width, and three morphometric indexes were introduced: 1 - the long-length longitudinal index of the lower jaw; 2 - longitude latitudinal index of the body of the lower jaw; 3 - latitudinal-altitude index of the branches of the lower jaw. According to these indices, 9 groups of jaws with different shapes were identified. In these groups, the values of 35 morphometric parameters of the body and branches of the lower jaw were studied. Results. It was found that statistically significant differences (p <0.05) between the groups of jaws, determined by the value of the altitude-longitude index of the lower jaw and the longitude-latitude index of the body of the lower jaw, exist between the same morphometric parameters: angular width, projection length from the corners and chin angle , and most of the morphometric parameters of the body and branches of the lower jaw do not statistically significantly differ between the extreme forms (dolicho- and brachi, lepto- and eurimandibular). There are statistically significant differences between the jaw groups, systematized by the latitude-altitude index of the branch of the lower jaw (p <0.05) for most of the studied indicators of the branch of the lower jaw: branch height, smallest branch width, notch width, notch angle, base of the coronoid process , the base of the condylar process, the distance from the front edge of the lower jaw branch to the opening of the lower jaw, the distance from the notch of the lower jaw to the opening of the lower jaw, the distance from the angle of the lower jaw to the opening of the lower jaw. It has been proved that in the lower jaws with a hypsiramimandibular form, the values of the smallest branch width, the base length of the coronoid and condylar processes, as well as the distance from the front edge of the branch to the opening of the lower jaw are significantly smaller, however, the values of the branch height, notch angle, notch width, notch distance the angle of the lower jaw to its opening is larger compared to the platyramimandibular form (p˂0.05). Conclusion. The greatest number of differences in the value of morphometric parameters is observed during the systematization of the lower jaw according to the shape of its branch. This can be explained by the fact that it is under the direct influence of the masticatory muscles, performing not only supporting, protective, but also motor function.

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Ryerson, William G., and Tate Van Valkenburg. "Linking Tooth Shape to Strike Mechanics in the Boa constrictor." Integrative and Comparative Biology 61, no. 2 (March 22, 2021): 759–71. http://dx.doi.org/10.1093/icb/icab009.

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Synopsis Snakes, with the obvious exception of the fangs, are considered to lack the regional specialization of tooth shape and function which are exemplified by mammals. Recent work in fishes has suggested that the definition of homodont and heterodont are incomplete without a full understanding of the morphology, mechanics, and behavior of feeding. We investigated this idea further by examining changes in tooth shape along the jaw of Boa constrictor and integrating these data with the strike kinematics of boas feeding on rodent prey. We analyzed the shape of every tooth in the skull, from a combination of anesthetized individuals and CT scanned museum specimens. For strike kinematics, we filmed eight adult boas striking at previously killed rats. We determined the regions of the jaws that made first contact with the prey, and extrapolated the relative positions of those teeth at that moment. We further determined the roles of all the teeth throughout the prey capture process, from the initiation of the strike until constriction began. We found that the teeth in the anterior third of the mandible are the most upright, and that teeth become progressively more curved posteriorly. Teeth on the maxilla are more curved than on the mandible, and the anterior teeth are more linear or recurved than the posterior teeth. In a majority of strikes, boas primarily made contact with the anterior third of the mandible first. The momentum from the strike caused the upper jaws and skull to rotate over the rat. The more curved teeth of the upper jaw slid over the rat unimpeded until the snake began to close its jaws. In the remaining strikes, boas made contact with the posterior third of both jaws simultaneously, driving through the prey and quickly retracting, ensnaring the prey on the curved posterior teeth of both jaws. The curved teeth of the palatine and pterygoid bones assist in the process of swallowing.

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Terva, Juuso, Kati Valtonen, Pekka Siitonen, and Veli-Tapani Kuokkala. "Correlation of wear and work in dual pivoted jaw crusher tests." Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 234, no. 3 (September 15, 2018): 334–49. http://dx.doi.org/10.1177/1350650118795566.

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A laboratory sized jaw crusher with uniform movement of the jaws, the dual pivoted jaw crusher, was used to determine the relationship between wear and work. Wear was concentrated on the jaw plates opposing each other and was measured as mass loss of the specimens. Work was measured directly from the force and displacement of the instrumented jaw, which allowed work to accumulate only from the actual crushing events. The tests were conducted with several jaw geometries and with two motional settings, where the relation of compressive and sliding motion between the jaws was varied. The tests showed that the relation between wear and work was constant in many of the tested cases. In certain tests with larger lateral and faster contact speed, wear occurred at relatively lower amounts of work. This behavior was more definite when the relation of wear and work was investigated using modified Archards wear equation. The results indicate that the lower amount of needed work could stem from the material reaching a dynamic situation, where the flow stress becomes increasingly strain-rate dependent.

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Neenan, James M., Marcello Ruta, Jennifer A. Clack, and Emily J. Rayfield. "Feeding biomechanics in Acanthostega and across the fish–tetrapod transition." Proceedings of the Royal Society B: Biological Sciences 281, no. 1781 (April 22, 2014): 20132689. http://dx.doi.org/10.1098/rspb.2013.2689.

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Acanthostega is one of the earliest and most primitive limbed vertebrates. Its numerous fish-like features indicate a primarily aquatic lifestyle, yet cranial suture morphology suggests that its skull is more similar to those of terrestrial taxa. Here, we apply geometric morphometrics and two-dimensional finite-element analysis to the lower jaws of Acanthostega and 22 other tetrapodomorph taxa in order to quantify morphological and functional changes across the fish–tetrapod transition. The jaw of Acanthostega is similar to that of certain tetrapodomorph fish and transitional Devonian taxa both morphologically (as indicated by its proximity to those taxa in morphospace) and functionally (as indicated by the distribution of stress values and relative magnitude of bite force). Our results suggest a slow tempo of morphological and biomechanical changes in the transition from Devonian tetrapod jaws to aquatic/semi-aquatic Carboniferous tetrapod jaws. We conclude that Acanthostega retained a primitively aquatic lifestyle and did not possess cranial adaptations for terrestrial feeding.

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Gorman, Jessica. "Worm's Jaws Show Mettle." Science News 164, no. 5 (August 2, 2003): 69. http://dx.doi.org/10.2307/3982186.

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Andrejs, J. "Dentigerous Cysts of Jaws." Česká stomatologie/Praktické zubní lékařství 116, no. 2 (June 1, 2016): 25–32. http://dx.doi.org/10.51479/cspzl.2016.017.

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Benedetti, A., S. Naumovski, V. Popovski, and B. Ilievski. "Controversy about jaws adamantinoma." International Journal of Oral and Maxillofacial Surgery 34 (January 2005): 70. http://dx.doi.org/10.1016/s0901-5027(05)81150-6.

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Widmark, Göran, Sören Sagne, and Pablo Heikel. "Osteoradionecrosis of the jaws." International Journal of Oral and Maxillofacial Surgery 18, no. 5 (October 1989): 302–6. http://dx.doi.org/10.1016/s0901-5027(89)80100-6.

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