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

Decreased mortality of abdominal aortic aneurysms in a peripheral county

Objectives:To analyse the effect on the mortality associated with abdominal aortic aneurysms, due to the establishment of a decentralised vascular surgical unit in the county of Viborg.Methods:Death after aneurysm repair and from rupture without repair were analysed retrospectively for the 3 year period before (1986–88), and after (1989–91), the unit was established.Results:Between 1986 and 1988, one patient (5%) died after 19 elective and three emergency non-ruptured aneurysm repairs. Only three ruptures were repaired with two deaths. In the county, 41 deaths due to ruptured aneurysm were recorded. Between 1989 and 1991 two patients (4%) died after 26 elective and 27 emergency non-ruptured aneurysm repairs. Nineteen ruptures were repaired with six deaths (32%). In the county, 28 deaths due to rupture were recorded during this period.Conclusions:The establishment of a decentralised vascular surgical unit has increased the proportion of ruptured aneurysms reaching surgery with a resultant decrease in mortality from this condition

Greater family size is associated with less cancer risk: an ecological analysis of 178 countries

Background: Greater family size measured with total fertility rate (TFR) and with household size, may offer more life satisfaction to the family members. Positive psychological well-being has been postulated to decrease cancer initiation risk. This ecological study aims to examine the worldwide correlation between family size, used as the measure of positive psychological well-being, and total cancer incidence rates. Methods: Country specific estimates obtained from United Nations agencies on total cancer incidence rates (total, female and male rates in age range 0–49 years and all ages respectively), all ages site cancer incidence (bladder, breast, cervix uteri, colorectum, corpus uteri, lung, ovary and stomach), TFR, household size, life expectancy, urbanization, per capita GDP PPP and self-calculated Biological State Index (Ibs) were matched for data analysis. Pearson’s, non-parametric Spearman’s, partial correlations, independent T-test and multivariate regressions were conducted in SPSS. Results: Worldwide, TFR and household size were significantly and negatively correlated to all the cancer incidence variables. These correlations remained significant in partial correlation analysis when GDP, life expectancy, Ibs and urbanization were controlled for. TFR correlated to male cancer incidence rate (all ages) significantly stronger than it did to female cancer incidence rate (all ages) in both Pearson’s and partial correlations. Multivariate stepwise regression analysis indicated that TFR and household size were consistently significant predictors of all cancer incidence variables. Conclusions: Countries with greater family size have lower cancer risk in both females, and especially males. Our results seem to suggest that it may be worthwhile further examining correlations between family size and cancer risk in males and females through the cohort and case-control studies based on large samples.Wenpeng You, Frank J Rühli, Renata J Henneberg and Maciej Henneber

Genghis Khan's death (AD 1227): An unsolvable riddle or simply a pandemic disease?

The article examines Genghis Khan's death from the historico-medical perspective. Although several etiologies have been proposed over the years, most of these at a closer look appear to be later inventions by historians. A reassessment of the available evidence suggests instead bubonic plague as the most likely clinical scenario. Genghis Khan's death is also a reflection on the impact of pandemic diseases on leadership in ancient times as well as nowadays

Completeness and positive predictive value of registration of upper limb embolectomy in the Danish National Vascular Registry

Ljubica V Andersen1, Leif S Mortensen2, Jes S Lindholt3, Ole Faergeman4, Eskild W Henneberg3, Lars Frost51Department of Pharmacology, Odense University Hospital, Denmark; 2UNI-C, The Danish IT Centre for Education and Research, Aarhus, Denmark; 3Vascular Research Unit, Department of Vascular Surgery, Viborg Hospital, Denmark; 4Department of Cardiology and Internal Medicine, Aarhus University Hospital, Denmark; 5Department of Medicine, Silkeborg Hospital, DenmarkObjective: To evaluate completeness and positive predictive value of the Danish National Vascular Registry regarding registration of the surgical procedures: embolectomy of brachial, ulnar, or radial artery. Study design and settings: The study was based on first-time embolectomies in the brachial, ulnar, or radial artery performed in Denmark from January 1, 1990 to December 31, 2002. The data were primarily retrieved from the Danish National Vascular Registry and secondarily from the Danish National Registry of Patients. Medical records were retrieved using a standardized form.Results: In total, 1433 incident cases of first-time embolectomy were found in both registries. The positive predictive value of the registration was 97.5% (95% confidence interval [CI]; 96.4–98.4). The degree of completeness was 86.5% (95% CI; 84.3–88.5). For the registration period from 1990 till 1996 the degree of completeness was 78.2% (95% CI; 74.4–81.7), and from 1997 till 2002 it was 93.8% (95% CI; 91.6–95.7). Conclusion: The completeness and positive predictive value of registration of embolectomy in the upper limb in the Danish National Vascular Registry was 86.5% and 97.5%, respectively. This registry can be a valuable tool for epidemiological research and quality-monitoring. Keywords: positive predictive value, completeness, capture-recapture method, validity, embolectomy, registration

New perspectives on evolutionary medicine: the relevance of microevolution for human health and disease

Evolutionary medicine (EM) is a growing field focusing on the evolutionary basis of human diseases and their changes through time. To date, the majority of EM studies have used pure theories of hominin macroevolution to explain the present-day state of human health. Here, we propose a different approach by addressing more empirical and health-oriented research concerning past, current and future microevolutionary changes of human structure, functions and pathologies. Studying generation-to-generation changes of human morphology that occurred in historical times, and still occur in present-day populations under the forces of evolution, helps to explain medical conditions and warns clinicians that their current practices may influence future humans. Also, analyzing historic tissue specimens such as mummies is crucial in order to address the molecular evolution of pathogens, of the human genome, and their coadaptations.Frank Jakobus Rühli and Maciej Henneber

Two interpretations of human evolution: Essentialism and Darwinism

Despite intensive studies of a large number of fossils discovered during the 20th century there is no consensus as to the interpretation of the process of hominin evolution. Some authors see as many as six genera and some 17 species, while others argue for a single lineage from Plio/Pleistocene until today. Such diversity of interpretations of the same facts indicates lack of a uniform theoretical basis underlying studies of human evolution. Debates can be resolved using basic principles of scientific inquiry - parsimony and falsification of null hypotheses. Hypothesis testing is now possible with respect to the evolution of basic hominin characteristics such as brain size, body size and the size of the dentition that have sample sizes of a few hundred individual data points each. These characters display a continuous change with time. Analyses of variance do not falsify the null hypothesis of the existence of only one species at any time - variances around regression lines on time do not differ from the variance observed in the single species of Homo sapiens - distributions of residuals are normal. Thus, splitting of the hominin lineage into coeval species can only be based on descriptive characteristics that are liable to errors of subjective judgment.Maciej Henneber

Perforated Meckel's diverticulum presenting with combined bowel and urinary obstruction and mimicking Crohn's disease: a case report

<p>Abstract</p> <p>Introduction</p> <p>Meckel's diverticulum is a common congenital anomaly of the gastrointestinal tract, but is an uncommon cause of serious complications in adults. Although cases of patients with hemorrhage, bowel obstruction or perforation associated with Meckel's diverticulum have been reported, there have been no prior reports of patients with combined urinary and bowel obstruction due to abscess formation.</p> <p>Case presentation</p> <p>We describe the case of a 21-year-old man with a history of recurrent papillary thyroid cancer, but no prior abdominal surgeries, who presented with a one-month history of rectal pain and new-onset obstipation with urinary retention. He reported night sweats and weight loss, and had a second-degree relative with known Crohn's disease. A digital rectal examination was notable and revealed marked tenderness with proximal induration. A computed tomography scan of the patient's abdomen revealed a large, complex, circumferential perirectal abscess compressing the rectal lumen and base of the urinary bladder, associated with terminal ileal thickening and an ileocecal fistula. A flexible sigmoidoscopy with an endorectal ultrasound scan displayed a complex abscess with extensive mucosal and surrounding inflammation. An exploratory laparotomy revealed a Meckel's diverticulum with a large perforation at its base, positioned near the ileocecal fistula and immediately superior to the perirectal abscess. The section of small bowel containing the Meckel's diverticulum, the terminal ileum, and the cecum, were all resected, and the abscess was debrided.</p> <p>Conclusions</p> <p>Pre-operative diagnosis of Meckel's diverticulum can be difficult. If the nature of the complication makes ultimate surgical management likely, an early laparoscopic or open exploration should be performed to prevent the morbidity and mortality associated with late complications.</p