Sharpness of teeth in man and other primates

Analyses of wear characteristics on the teeth of a young adult male baboon, a male native human from New Guinea and a male Caucasian from New Zealand are made, and their inseparable relationship to behavior emphasized. These characteristics provide evidence of the evolution of precise anatomical and innate behavioral tooth-grinding mechanisms specific to the production of sharp teeth. Although the teeth on eruption have some degree of morphological sharpness, the tooth-grinding behavior perfects this sharpness and subsequently maintains it throughout the functional life of the teeth. The male baboon, used here as broadly representative of man\u27s non-hominid relatives and ancestors, has a specialized, sickle-like, vertically oriented upper canine, sharpened specifically as a slashing weapon. The lower anterior premolars are the honing tools which grind against the upper canines in a motion opposite to that of the masticatory stroke. These premolars are noticeably specialized for this tooth-to-tooth grinding action by their enlarged buccal crown-faces, thickened enamel gingival extensions, and by paired roots placed perpendicular to the whetstone faces. In contrast, man\u27s short-canine condition has evolved to provide a specialized, horizontally sharp shearing device. The continuous rows of even, constantly sharpened teeth, vertically oriented and firmly anchored in jaws which provide greater force at the biting teeth, give man the capacity for powerful, lethal, segmentive biting. Thus man\u27s dentition is seen not as generalized , and certainly not as regressed or weakened , but as highly specialized. The significance of the short-canine condition (currently regarded as a diagnostic feature of hominids) is not that man has become biologically defenseless, but that the hominid dental mechanism has harnessed attritional wear to provide a more stable and durably functional weapon. It is concluded that tooth-sharpening and related phenomena are evidence of innate behavior related to a specialized, viable, biological weapon in Homo sapiens, and because this weapon — the teeth — is the primary one and has been overlooked it emphasizes a corollary: intraspecies use of the teeth is strictly controlled by genetical determinants, whereas such control of the secondary weapon —the hand — is slight

Use of angiotensin-converting enzyme inhibitors at discharge in patients with acute myocardial infarction in the United States: data from the National Registry of Myocardial Infarction 2

AbstractObjectives: This study was undertaken to examine recent trends in the use of angiotensin-converting enzyme (ACE) inhibitor therapy in patients discharged after acute myocardial infarction (AMI) and to identify clinical factors associated with ACE inhibitor prescribing patterns.Background: Clinical trials have demonstrated a significant mortality benefit in patients treated with ACE inhibitors after AMI. Numerous studies have demonstrated underuse of other beneficial treatments for patients with AMI, such as beta-adrenergic blocking agents, aspirin and immediate reperfusion therapy.Methods: Demographic, procedural and discharge medication data from 190,015 patients with AMI were collected at 1,470 U.S. hospitals participating in the National Registry of Myocardial Infarction 2.Results: Prescriptions for ACE inhibitor therapy at hospital discharge increased from 25.0% in 1994 to 30.7% in 1996. Patients with a left ventricular ejection fraction ≤40% or evidence of congestive heart failure while in the hospital were discharged with ACE inhibitor treatment 42.6% of the time. Of patients experiencing an anterior wall myocardial infarction and no evidence of heart failure, 26.1% of patients were discharged with this treatment. Of the remaining patients, 15.6% received ACE inhibitors at discharge. ACE inhibitors were prescribed more often to elderly and diabetic patients as well as those requiring intraaortic balloon pump placement. This therapy was given less often to patients who underwent revascularization with coronary angioplasty or coronary artery bypass graft surgery or were treated with calcium channel blocking agents.Conclusions: Physicians are prescribing ACE inhibitors in patients with myocardial infarction with increasing frequency. Those patients with the greatest expected benefit receive ACE inhibitor treatment most often. However, the majority of even these high risk patients were not discharged with this life-saving therapy

Early angiography versus conservative treatment in patients with non–ST elevation acute myocardial infarction

AbstractOBJECTIVESTo compare short- and long-term outcome after early invasive or conservative strategies in the treatment of non-ST segment elevation acute myocardial infarction (AMI).BACKGROUNDIt is uncertain whether or not there is benefit from emergent invasive diagnosis and treatment of AMI in patients without ST segment elevation on the admission electrocardiogram (ECG).METHODSIn a cohort of 1,635 consecutive patients with AMI who presented to hospitals without ST segment elevation on their admission ECG, we compared treatments, hospital course and outcome in 308 patients who presented to hospitals whose initial strategy favored early angiography and appropriate intervention when indicated versus 1,327 similar patients who presented to hospitals that favor a more conservative initial approach.RESULTSAt baseline, patients admitted to hospitals favoring an early invasive strategy were younger, more predominately Caucasian and had less comorbidity. Early coronary angiography occurred in 58.8% versus 8% (p < 0.001), and early angioplasty was performed in 44.8% versus 6.1% (p < 0.001) in the two different cohorts. Patients treated in hospitals favoring the early invasive strategy had a lower 30-day (5.5% vs. 9.5%, p = 0.026) and four-year mortality (20% vs. 37%, p < 0.001). Multivariate analysis showed a trend towards lower hospital mortality (OR = 0.56, 95% CI: 0.29 to 1.09) and a significant lower long-term mortality (hazard ratio = 0.61, 95% CI: 0.47 to 0.80) in patients admitted to hospitals favoring an early invasive strategy.CONCLUSIONSThese data suggested that an early invasive strategy in patients with AMI and nondiagnostic ECG changes is associated with lower long-term mortality

Negative linear compressibility in common materials

© 2015 AIP Publishing LLC. Negative linear compressibility (NLC) is still considered an exotic property, only observed in a few obscure crystals. The vast majority of materials compress axially in all directions when loaded in hydrostatic compression. However, a few materials have been observed which expand in one or two directions under hydrostatic compression. At present, the list of materials demonstrating this unusual behaviour is confined to a small number of relatively rare crystal phases, biological materials, and designed structures, and the lack of widespread availability hinders promising technological applications. Using improved representations of elastic properties, this study revisits existing databases of elastic constants and identifies several crystals missed by previous reviews. More importantly, several common materials - drawn polymers, certain types of paper and wood, and carbon fibre laminates - are found to display NLC. We show that NLC in these materials originates from the misalignment of polymers/fibres. Using a beam model, we propose that maximum NLC is obtained for misalignment of 26°. The existence of such widely available materials increases significantly the prospects for applications of NLC

Wear of human teeth: a tribological perspective

The four main types of wear in teeth are attrition (enamel-on-enamel contact), abrasion (wear due to abrasive particles in food or toothpaste), abfraction (cracking in enamel and subsequent material loss), and erosion (chemical decomposition of the tooth). They occur as a result of a number of mechanisms including thegosis (sliding of teeth into their lateral position), bruxism (tooth grinding), mastication (chewing), toothbrushing, tooth flexure, and chemical effects. In this paper the current understanding of wear of enamel and dentine in teeth is reviewed in terms of these mechanisms and the major influencing factors are examined. In vitro tooth wear simulation and in vivo wear measurement and ranking are also discussed

Using coloured filters to reduce the symptoms of visual stress in children with reading delay

Background: Meares Irlen Syndrome (MIS), otherwise known as “visual stress”, is one condition that can cause difficulties with reading. Aim: This study aimed to compare the effect of two coloured-filter systems on the symptoms of visual stress in children with reading delay. Methods: The study design was a pre-test, post-test, randomized head-to-head comparison of two filter systems on the symptoms of visual stress in school children. A total of 68 UK mainstream schoolchildren with significant impairment in reading ability completed the study. Results: The filter systems appeared to have a large effect on the reported symptoms between pre and post three-month time points (d = 2.5, r = 0.78). Both filter types appeared to have large effects (Harris d = 1.79, r = 0.69 and DRT d = 3.22, r = 0.85). Importantly, 35% of participants’ reported that their symptoms had resolved completely; 72% of the 68 children appeared to gain improvements in three or more visual stress symptoms. Conclusion and significance: The reduction in symptoms, which appeared to be brought about by the use of coloured filters, eased the visual discomfort experienced by these children when reading. This type of intervention therefore has the potential to facilitate occupational engagement

Dampwood termite control

Published January 1973. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalo

Insect pests of home-stored foods

Published November 1962. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalo

Evaluating a multi-component intervention to reduce and break up office workers' sitting with sit-stand desks using the APEASE criteria

Objective: Sedentary workplace interventions have had success in reducing excessive sitting time in office workers, but barriers to implementation and uptake remain. This study formally assessed a theory-derived, sit-stand desk intervention using the APEASE (Acceptability, Practicability, Effectiveness, Affordability, Side-effects, Equity) criteria. / Methods: Thirteen adults (eight female, mean age 38 ± 10 years) from the treatment arm of a sedentary behaviour intervention participated in semi-structured interviews. Thematic codes were inductively assigned to data items followed by deductive charting using the APEASE criteria. / Results: The intervention was highly acceptable, practicable, safe to deploy, and helped workers reduce workplace sitting time, though individual preferences and workload mediated engagement. Affordability of sit-stand desks and Equity of access were potential barriers to uptake. / Conclusions: Through the lens of the APEASE criteria, this theory-derived, multi-component sit-stand desk intervention showed acceptability, practicability and effectiveness in reducing and breaking up sedentary time at work with minimal side effects. Using this approach with further tailoring and personalisation may help workers achieve greater reductions in workplace sitting, though affordability and equity should be considered further