The rigidity of periodic body-bar frameworks on the three-dimensional fixed torus

We present necessary and sufficient conditions for the generic rigidity of body-bar frameworks on the three-dimensional fixed torus. These frameworks correspond to infinite periodic body-bar frameworks in $\mathbb{R}^3$ with a fixed periodic lattice.Comment: 31 pages, 12 figure

Five-year Results of Elastin and Collagen Markers as Predictive Tools in the Management of Small Abdominal Aortic Aneurysms

AbstractObjective small abdominal aortic aneurysms (AAAs) do rupture and only half of AAAs above 5 cm would have ruptured unoperated. Furthermore, conservative treatment of AAAs may cause psychological side effects and impaired quality of life. To optimise the indication and time for operation for AAAs, we analysed whether serum elastin peptides (EP), procollagen-IIIN-terminal propeptide (PIIINP), and the initial AAA size could predict operation for AAAs in initially conservatively treated AAA. Material and methods in 1994, 4404 65–73 year old males were invited to hospital-based screening for AAAs by ultrasonography. Seventy-six percent attended. One hundred and forty-one (4.2%) had AAAs (def: +30 mm). Nineteen were offered operation (AAA +50 mm), and 112 were followed with annual control scans for 1–5 years (mean 2.5 years). Of these, 99 had their EP (ng/ml) and PIIINP (ng/ml) determined using ELISA and RIA techniques. Two observers and one scanner were used. Results the mean expansion rate was 2.7 mm/year. The initial AAA size (r=0.46; 0.26–0.61), EP ( r =0.31; 0.11–0.49), and NPIIIP ( r =0.24; 0.02–0.44) was independently significant associated to expansion rate in a multiple linear regression analysis including the three mentioned variables. The multivariate formula could by ROC curve analysis predict cases reaching 5 cm in diameter within 5 years with a sensitivity and specificity of 91% and 87%, respectively, increasing to 91% and 94%, respectively, by accepting a 2 mm variation in those measurements. Twenty-three were lost to follow up, 21 of these due to death or severe illness. Of these, seven would have been predicted to reach an AAA size recommendable for surgery. If all 23 were included in the analysis, the sensitivity and specificity would have been 87% and 85%, respectively. Conclusion a predictive model using EP, PIIINP, and initial AAA size seems capable of predicting nine out of 10 AAAs that will be operated on within 5 years. However, a larger sample size is needed for clinical recommendations

The Plasma Level of Matrix Metalloproteinase 9 may Predict the Natural History of Small Abdominal Aortic Aneurysms. A Preliminary Study

AbstractObjectives: increased levels of various proteinases have been detected in abdominal aortic aneurysms (AAA) and are assumed to cause the degradation of the aortic wall. To determine whether systemic measurement of these proteinases and their inhibitors may predict the natural cause of AAA. Methods and material: serum (S) and plasma (P) samples were obtained from 121 men following the diagnosis of a small AAA (3–5 cm) at population screening. Annual control scans were performed to check for expansion. Circulating levels of elastase-alpha 1 antitrypsin-complexes, alpha 1antitrypsin, matrix metalloproteinase (MMP) 2 & 9, tissue-inhibitor-matrixproteinase 1 & 2, procollagen III-N-terminal-propeptide, and elastin-peptides were measured in a random group of 36 men. Results: alpha 1 antitrypsin was significantly and positively associated with expansion. Similarly, P-MMP9 levels were significantly associated with size and expansion. There was a difference between median serum and plasma values, probably because of secretion from platelets. Conclusion: P-MMP9 and P-alpha 1 antitrypsin may predict the natural history of AAA

Heredity, Environment, and Cranial Form: A Reanalysis of Boas's Immigrant Data

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65137/1/aa.2003.105.1.125.pd

Lessons from history of socioeconomic improvements: a new approach to treating multi-drug-resistant tuberculosis

Summary This study investigated the trends in tuberculosis mortality through time in Switzerland. Information on the decline in mortality before chemotherapies were introduced may be useful in developing countries where drug-resistant tuberculosis is now becoming a major problem. Swiss data were collected from historical records and comparative data were obtained from the literature for England and Wales, New York, Japan, Brazil and Sierra Leone. Logistic curves were fitted to examine the rate of decline before introduction of pharmacotherapies and these show that the decline would have continued without the introduction of chemical therapies, including antibiotics. In Switzerland, England and Wales and New York, the decline had occurred long before the introduction of specific anti-tuberculosis agents. In Brazil and Japan, chemical therapy was co-incident with the decline in tuberculosis mortality rates. Overall, it is suggested that the effective control of tuberculosis can be achieved through a combination of chemical interventions, conservative therapy (rest, good nutrition, ventilation, etc.) as well as public health interventions addressing hygiene, nutrition, reducing exposure to infections and educating the population about tuberculosis

Imaging ancient and mummified specimens: dual-energy CT with effective atomic number imaging of two ancient Egyptian cat mummies

In mummified animals and humans, soft tissues like skin and muscle become more dense over time due to dehydration. At the same time, bone becomes less dense as marrow is replaced by air. This is a problem for the radiological examination of ancient specimens, as currently used methods such as single-energy CT and MRI rely on density and water content to produce tissue contrast in an image. Dual energy CT with effective atomic number imaging overcomes this problem, as the elemental constituents and consequently effective atomic number of a specimen remain relatively constant over time. This case study of two ancient Egyptian cat mummies demonstrates that effective atomic number imaging can differentiate desiccated soft tissues from low-density bone in ancient remains. Effective atomic number imaging has the potential for superior tissue contrast resolution when compared to single energy CT and can be used to provide new paleoradiological perspectives.James M. Bewes, Antony Morphett, F. Donald Pate, Maciej Henneberg, Andrew J. Low, Lars Kruse, Barry Craig, Aphrodite Hindson, Eleanor Adam

LESSONS FROM HISTORY OF SOCIOECONOMIC IMPROVEMENTS: A NEW APPROACH TO TREATING MULTI-DRUG-RESISTANT TUBERCULOSIS

This study investigated the trends in tuberculosis mortality through time in Switzerland. Information on the decline in mortality before chemotherapies were introduced may be useful in developing countries where drug-resistant tuberculosis is now becoming a major problem. Swiss data were collected from historical records and comparative data were obtained from the literature for England and Wales, New York, Japan, Brazil and Sierra Leone. Logistic curves were fitted to examine the rate of decline before introduction of pharmacotherapies and these show that the decline would have continued without the introduction of chemical therapies, including antibiotics. In Switzerland, England and Wales and New York, the decline had occurred long before the introduction of specific anti-tuberculosis agents. In Brazil and Japan, chemical therapy was co-incident with the decline in tuberculosis mortality rates. Overall, it is suggested that the effective control of tuberculosis can be achieved through a combination of chemical interventions, conservative therapy (rest, good nutrition, ventilation, etc.) as well as public health interventions addressing hygiene, nutrition, reducing exposure to infections and educating the population about tuberculosi

New interpretation of arterial stiffening due to cigarette smoking using a structurally motivated constitutive model

Cigarette smoking is the leading self-inflicted risk factor for cardiovascular diseases; it causes arterial stiffening with serious sequelea including atherosclerosis and abdominal aortic aneurysms. This work presents a new interpretation of arterial stiffening caused by smoking based on data published for rat pulmonary arteries. A structurally motivated “four fiber family” constitutive relation was used to fit the available biaxial data and associated best-fit values of material parameters were estimated using multivariate nonlinear regression. Results suggested that arterial stiffening caused by smoking was reflected by consistent increase in an elastin-associated parameter and moreover by marked increase in the collagen-associated parameters. That is, we suggest that arterial stiffening due to cigarette smoking appears to be isotropic, which may allow simpler phenomenological models to capture these effects using a single stiffening parameter similar to the approach in isotropic continuum damage mechanics. There is a pressing need, however, for more detailed histological information coupled with more complete biaxial mechanical data for a broader range of systemic arteries