Project description:Bats are the only mammals capable of powered flight. One of the oldest bats known from a complete skeleton is Onychonycteris finneyi from the Early Eocene (Green River Formation, Wyoming, 52.5 Ma). Estimated to weigh approximately 40 g, Onychonycteris exhibits the most primitive combination of characters thus far known for bats. Here, we reconstructed the aerofoil of the two known specimens, calculated basic aerodynamic variables and compared them with those of extant bats and gliding mammals. Onychonycteris appears in the edges of the morphospace for bats, underscoring the primitive conformation of its flight apparatus. Low aerodynamic efficiency is inferred for this extinct species as compared to any extant bat. When we estimated aerofoil variables in a model of Onychonycteris excluding the handwing, it closely approached the morphospace of extant gliding mammals. Addition of a handwing to the model lacking this structure results in a 2.3-fold increase in aspect ratio and a 28% decrease in wing loading, thus greatly enhancing aerodynamics. In the context of these models, the rapid evolution of the chiropteran handwing via genetically mediated developmental changes appears to have been a key transformation in the hypothesized transition from gliding to flapping in early bats.
Project description:Objective: Otitis media is known to alter expression of cytokine and other genes in the mouse middle ear and inner ear. However, whole mouse genome studies of gene expression in otitis media have not previously been undertaken. Ninety-nine percent of mouse genes are shared in the human, so these studies are relevant to the human condition. Methods: To assess inflammation-driven processes in the mouse ear, gene chip analyses were conducted on mice treated with trans-tympanic heat-killed Hemophilus influenza using untreated mice as controls. Middle and inner ear tissues were separately harvested at 6 hours, RNA extracted, and samples for each treatment processed on the Affymetrix 430 2.0 Gene Chip for expression of its 34,000 genes. Results: Statistical analysis of gene expression compared to control mice showed significant alteration of gene expression in 2,355 genes, 11% of the genes tested and 8% of the mouse genome. Significant middle and inner ear upregulation (fold change >1.5, p<0.05) was seen in 1,081 and 599 genes respectively. Significant middle and inner ear downregulation (fold change <0.67, p<0.05) was seen in 978 and 287 genes respectively. While otitis media is widely believed to be an exclusively middle ear process with little impact on the inner ear, the inner ear changes noted in this study were numerous and discrete from the middle ear responses. This suggests that the inner ear does indeed respond to otitis media and that its response is a distinctive process. Numerous new genes, previously not studied, are found to be affected by inflammation in the ear. Conclusion: Whole genome analysis via gene chip allows simultaneous examination of expression of hundreds of gene families influenced by inflammation in the middle ear. Discovery of new gene families affected by inflammation may lead to new approaches to the study and treatment of otitis media. There are 8 control samples and 9 samples trans-tympanically injected with H flu 10e9 for 6 hours. Each sample is from a single animal.
Project description:NTHi bacteria or saline were inoculated into the middle ears of mice. Mice were sacrificed at various times to monitor the course of infection. We used Mouse430_2 arrays to profile gene expression in response to bacterial infection RNA extracted at sacrifice
Project description:The transfer function H(V) between stapes velocity V(S) and sound pressure near the tympanic membrane P(TM) is a descriptor of sound transmission through the middle ear (ME). The ME power transmission efficiency (MEE), the ratio of sound power entering the cochlea to power entering the middle ear, was computed from H(V) measured in seven chinchilla ears and previously reported measurements of ME input admittance Y(TM) and ME pressure gain G(MEP) [Ravicz and Rosowski, J. Acoust. Soc. Am. 132, 2437-2454 (2012); J. Acoust. Soc. Am. 133, 2208-2223 (2013)] in the same ears. The ME was open, and a pressure sensor was inserted into the cochlear vestibule for most measurements. The cochlear input admittance Y(C) computed from H(V) and G(MEP) is controlled by a combination of mass and resistance and is consistent with a minimum-phase system up to 27 kHz. The real part Re{Y(C)}, which relates cochlear sound power to inner-ear sound pressure, decreased gradually with frequency up to 25 kHz and more rapidly above that. MEE was about 0.5 between 0.1 and 8 kHz, higher than previous estimates in this species, and decreased sharply at higher frequencies.
Project description:A comparative study of ossicular reconstrution using four different graft material was carried out on 40 patients as a second stage procedure from July 1989 to June 1991. The graft materials used were : aulologus ossicular bone graft, allogeneic ossicular bone graft, autologus cartilage and bio-compatible materials. All patients were observed for a period ranging from one to two years. Extrusion of ossicular graft was prevented by use of a lace of cartilage between the ossicular graft and neotympanic membrance. Satisfactory results were obtained with cartilage graft in 6%, allogeneic ossicles 70%, autologus ossicular graft 80% and bio-compatible materials 33.3%.
Project description:IntroductionMiddle ear barotrauma (MEBt) is the most common medical complication in diving, posing a serious risk to dive safety. Given this prevalence and the continuing growth of the diving industry, a comprehensive overview of the condition is warranted.MethodsThis was a survey study. An anonymous, electronic questionnaire was distributed to 7,060 recipients: professional divers of the Finnish Border Guard, the Finnish Rescue Services, and the Finnish Heritage agency; and recreational divers registered as members of the Finnish Divers' Association reachable by e-mail (roughly two-thirds of all members and recreational divers in Finland). Primary outcomes were self-reported prevalence, clinical characteristics, and health effects of MEBt while diving. Secondary outcomes were adjusted odds ratios (OR) for frequency of MEBt with respect to possible risk factors.ResultsA total of 1,881 respondents participated in the study (response rate 27%). In total, 81% of the respondents had experienced MEBt while diving. Of those affected, 38% had used medications and 1% had undergone otorhinolaryngology-related surgical procedures due to MEBt. Factors most associated with MEBt were poor subjective success in Valsalva ('occasionally' versus 'always' successful: OR 11.56; 95% CI 7.24-18.47) and Toynbee ('occasionally' versus 'always' successful: OR 3.51; 95% CI 1.95-6.30) manoeuvres.ConclusionsMEBt is common in both recreational and professional divers, having affected 81% of the respondents. The main possible risk factors include poor success in pressure equalisation manoeuvres.
Project description:We present a very rare case of tophaceous gout of the middle ear causing conductive hearing loss, with special emphasis on Computed Tomography presentation.
Project description:Middle ear diseases in childhood play an important role in daily ENT practice due to their high incidence. Some of these like acute otitis media or otitis media with effusion have been studied extensively within the last decades. In this article, we present a selection of important childhood middle ear diseases and discuss the actual literature concerning their treatment, management of complications and outcome. Another main topic of this paper deals with the possibilities of surgical hearing rehabilitation in childhood. The bone-anchored hearing aid BAHA(®) and the active partially implantable device Vibrant Soundbridge(®) could successfully be applied for children. In this manuscript, we discuss the actual literature concerning clinical outcomes of these implantable hearing aids.
Project description:This paper deals with the control of a redundant cobot arm to accomplish peg-in-hole insertion tasks in the context of middle ear surgery. It mainly focuses on the development of two shared control laws that combine local measurements provided by position or force sensors with the globally observed visual information. We first investigate the two classical and well-established control modes, i.e., a position-based end-frame tele-operation controller and a comanipulation controller. Based on these two control architectures, we then propose a combination of visual feedback and position/force-based inputs in the same control scheme. In contrast to the conventional control designs where all degrees of freedom (DoF) are equally controlled, the proposed shared controllers allow teleoperation of linear/translational DoFs while the rotational ones are simultaneously handled by a vision-based controller. Such controllers reduce the task complexity, e.g., a complex peg-in-hole task is simplified for the operator to basic translations in the space where tool orientations are automatically controlled. Various experiments are conducted, using a 7-DoF robot arm equipped with a force/torque sensor and a camera, validating the proposed controllers in the context of simulating a minimally invasive surgical procedure. The obtained results in terms of accuracy, ergonomics and rapidity are discussed in this paper.