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Anatomically based modelling of the human skull and jaw   总被引:3,自引:0,他引:3  
We present here an anatomically based model of the human masticatory system that provides a framework for simulating the complex chewing process. The initial motivation for creating this model was the desire to have a computational model of the human jaw that can be used to simulate the action of simple bites, and to calculate the stresses and forces on the teeth that are involved. The model created also provides a platform that can be used to investigate other features of the masticatory system. To construct this global model, individual models of the bones of the skull and jaw were created from generic data sets. Geometric models of the muscles of mastication were also created and attached to the appropriate bones. To complete this initial model, representations of the crowns of the teeth were created and a basic model of the temporomandibular joint (TMJ) was included. The finite element method was used to solve for the stresses and strains created by the loading conditions during a clenching simulation involving the mandible bone. The model presented here is also discussed in relation to a model of the entire musculo-skeletal system being developed as part of the Physiome Project.  相似文献   
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Essen SD 《Today's FDA》2011,23(6):62-68
Information technology is vital to operations, marketing, accounting, finance and administration. One of the most exciting and quickly evolving technologies in the modern dental office is digital applications. The dentist is often the business manager, information technology officer and strategic planning chief for his small business. The information systems triangle applies directly to this critical manager supported by properly trained ancillary staff and good equipment. With emerging technology driving all medical disciplines and the rapid pace at which it emerges, it is vital for the contemporary practitioner to keep abreast of the newest information technology developments. This article compares the strategic and operational advantages of digital applications, specifically imaging. The focus of this paper will be on digital radiography (DR), 3D computerized tomography, digital photography and digitally-driven CAD/CAM to what are now considered obsolescing modalities and contemplates what may arrive in the future. It is the purpose of this essay to succinctly evaluate the decisions involved in the role, application and implications of employing this tool in the dental environment  相似文献   
107.
We compared aspects of shape representation in extrastriate visual areas V2 and V4, which are both implicated in shape processing and belong to different hierarchical levels. We recorded responses of cells in awake, fixating monkeys to matched sets of contour and grating stimuli of low or intermediate complexity. These included simple stimuli (bars and sinusoids) and more complex stimuli (angles, intersections, arcs, and non-Cartesian gratings), all scaled to receptive field size. The responses of cells within each area were substantially modulated by each shape characteristic tested, with substantial overlap between areas by many response measures. Our analyses revealed many clear and reliable differences between areas in terms of the effectiveness of, and response modulation by, various shape characteristics. Grating stimuli were on average more effective than contour stimuli in V2 and V4, but the difference was more pronounced in V4. As a population, V4 showed greater response modulation by some shape characteristics (including simple shape characteristics) and V2 showed greater response modulation by many others (including complex shape characteristics). Recordings from area V1 demonstrated complex shape selectivity in some cells and relatively modest population differences in comparison with V2. Altogether, the representation of 2-dimensional shape characteristics revealed by this analysis varies substantially among the 3 areas. But surprisingly, the differences revealed by our analyses, individually or collectively, do not parallel the stepwise organization of the anatomical hierarchy. Commonalities of visual shape representation across hierarchical levels may reflect the replication of neural circuits used in generating complex shape representations at multiple spatial scales.  相似文献   
108.
Imbalances of 3p telomeric sequences cause 3p- and trisomy 3p syndrome, respectively, showing distinct, but also shared clinical features. No causative genes have been identified in trisomy 3p patients, but for the 3p- syndrome, there is growing evidence that monosomy for one or more of four genes at 3pter, CHL1, CNTN4, CRBN, and MEGAP/srGAP3, may play a causative role. We describe here an analysis of a complex chromosome 3p aberration in a severely mentally retarded patient that revealed two adjacent segments with different copy number gains and a distal deletion. The deletion in this patient included the loci for CHL1, CNTN4, and CRBN, and narrowed the critical segment associated with the 3p- syndrome to 1.5 Mb, including the loci for CNTN4 and CRBN. We speculate that the deletion contributes more to this patient's phenotype than the gains that were observed. We suggest that 3p- syndrome associated features are primarily caused by loss of CNTN4 and CRBN, with loss of CHL1 probably having an additional detrimental effect on the cognitive functioning of the present patient.  相似文献   
109.
Questions mark ears are an easily recognisable but uncommon malformation of the external ear. They can be found as an isolated malformation and are a pathognomonic sign of the auriculo-condylar syndrome. An additional unique sign in this syndrome may be present in the form of post-auricular tags. Such malformations should prompt further investigation for other signs of the auriculo-condylar syndrome.  相似文献   
110.

Background:

The Myocardial Infarction Network Essen was initiated in order to establish a standardized procedure with immediate reopening of the infarcted vessel for patients with ST‐elevation myocardial infarction (STEMI) in the city of Essen, Germany. The present study aims to evaluate gender‐related differences in presentation of disease and clinical outcome.

Hypothesis:

Gender is associated with differences in presentation and outcome of STEMI.

Methods:

All patients with STEMI were included without exception. Parameters such as risk profile, mortality, and relevant time intervals were documented. The follow‐up period was 1 year.

Results:

For this study, 1365 patients (72.1% male) were recruited. Women were significantly older, with higher prevalence of diabetes (28.1% vs 20.3%, P = 0.004) and hypertension (76.5% vs 64.8%, P<0.0005). Analysis of time intervals between symptoms to actions showed no significant differences. However, women tended to wait longer before calling for medical assistance (358 vs 331 min, P = 0.091). In‐hospital mortality was comparable with respect to gender, whereas women had higher 1‐year mortality (18.6% vs 13.2%). Age and diabetes were associated with a higher mortality. Adjusted for age, gender is no longer an independent risk factor. In the follow‐up period, significantly more women were readmitted to the hospital without a difference in the frequency of reangiography, surgery, or target‐vessel revascularization.

Conclusions:

The present data display a successful implementation of a standardized procedure in patients with STEMI. Although differences between genders are not as obvious as expected, efforts should be taken to perform a gender‐specific risk analysis as well as to promote education about proper behavior in case of new onset of angina. © 2011 Wiley Periodicals, Inc. The authors have no funding, financial relationships, or conflicts of interest to disclose.  相似文献   
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