Creep in oak material from the Vasa ship: verification of linear viscoelasticity and identification of stress thresholds

Creep deformation is a general problem for large wooden structures, and in particular for shipwrecks in museums. In this study, experimental creep data on the wooden cubic samples from the Vasa ship have been analysed to confirm the linearity of the viscoelastic response in the directions where creep was detectable (T and R directions). Isochronous stress-strain curves were derived for relevant uniaxial compressive stresses within reasonable time spans. These curves and the associated creep compliance values justify that it is reasonable to assume a linear viscoelastic behaviour within the tested ranges, given the high degree of general variability. Furthermore, the creep curves were fitted with a one-dimensional standard linear solid model, and although the rheological parameters show a fair amount of scatter, they are candidates as input parameters in a numerical model to predict creep deformations. The isochronous stress-strain relationships were used to define a creep threshold stress below which only negligible creep is expected. These thresholds ranges were 0.3-0.5 MPa in the R direction and 0.05-0.2 MPa in the T direction

25 Years of Self-organized Criticality: Concepts and Controversies

Introduced by the late Per Bak and his colleagues, self-organized criticality (SOC) has been one of the most stimulating concepts to come out of statistical mechanics and condensed matter theory in the last few decades, and has played a significant role in the development of complexity science. SOC, and more generally fractals and power laws, have attracted much comment, ranging from the very positive to the polemical. The other papers (Aschwanden et al. in Space Sci. Rev., 2014, this issue; McAteer et al. in Space Sci. Rev., 2015, this issue; Sharma et al. in Space Sci. Rev. 2015, in preparation) in this special issue showcase the considerable body of observations in solar, magnetospheric and fusion plasma inspired by the SOC idea, and expose the fertile role the new paradigm has played in approaches to modeling and understanding multiscale plasma instabilities. This very broad impact, and the necessary process of adapting a scientific hypothesis to the conditions of a given physical system, has meant that SOC as studied in these fields has sometimes differed significantly from the definition originally given by its creators. In Bak’s own field of theoretical physics there are significant observational and theoretical open questions, even 25 years on (Pruessner 2012). One aim of the present review is to address the dichotomy between the great reception SOC has received in some areas, and its shortcomings, as they became manifest in the controversies it triggered. Our article tries to clear up what we think are misunderstandings of SOC in fields more remote from its origins in statistical mechanics, condensed matter and dynamical systems by revisiting Bak, Tang and Wiesenfeld’s original papers

Impaired Secretory Function of the Prostate in Men With Oligo‐Asthenozoospermia

ABSTRACT: The secretory function of the human prostate and the seminal vesicles is a prerequisite for gel formation and liquefaction of semen, but the relation to poor sperm motility and low sperm count in infertile men remains to be clarifyed. Our aim was to evaluate the secretory function of the prostate and the seminal vesicles in normozoospermic men (n=35) and in asthenozoospermic men, who were all also oligozoospermic (n=27). All 62 subjects belonged to couples undergoing routine infertility evaluation. In liquefied seminal fluid we measured the concentrations of fructose and protein C inhibitor (PCI) contributed by the seminal vesicles, PCI complexed to prostate‐specific antigen (PSA), and the prostatic contribution of zinc, PSA, acid phosphatase (PAP), β‐microseminoprotein (β‐MSP), and Znα2‐glycoprotein (Znα2‐GP). The concentration of each prostatic secretory protein correlated significantly with that of zinc (P < 0.01) in both the normozoospermic (NZS) and oligo‐astheno‐zoospermic (OAZS) subgroups, but the PCI concentration did not correlate significantly with that of fructose. There was no significant difference between the NZS and OAZS subgroups in ejaculate volume or secretory contribution from the seminal vesicles, whereas the OAZS subgroup was characterized by significantly lower secretory contributions of Znα2‐GP (P = 0.001), Zn, PSA, PAP (P < 0.01), and β‐MSP (P < 0.05). The two subgroups did not differ significantly in the serum concentration of luteinizing hormone (LH), testosterone, or sex hormone‐binding globulin (SHBG). The results thus suggest the secretory contribution of major prostatic proteins and zinc per ejaculate to be significantly decreased in oligo‐asthenozoospermic men. The importance of this finding in relation to poor sperm count and motility as indicators of impaired gonadal function requires further investigation. 1995 American Society of Androlog

Abstract 411: Carvone contact allergy in southern Sweden : a 15-year retrospective study

Background: Carvone (L-carvone) is naturally found in spearmint oil and is considered a mild skin sensitizer. It commonly serves as a flavoring agent in toothpaste and other mint tasting products. There is recent evidence that carvone may have a relationship with oral lichenoid lesions (OLL). Objectives: The aim was to study the frequency of carvone contact allergy in a Swedish patch test population at the Malmö clinic and to investigate the characteristics of the group with special reference to OLL. Methods: A 15-year retrospective study including all consecutive patients tested positive for carvone with different series containing carvone. The patients’ records were reviewed in regard to symptoms, previous diagnoses, type of referrer and contact allergy. Results: Three thousand eight hundred and twelve patients were patch tested to different series containing l-carvone, the most common being the Swedish dental series. One hundred and forty-three patients (3.7%) were positive to carvone whereof 138 patients had records available for review. Of the carvone-sensitized patients, 46.9% had suspected or previously diagnosed OLL and 8.0% had dermal or genital lichen planus. The majority of the carvone-sensitized patients had also positive reactions to several other allergens. The most common allergens were spearmint oil (39.9%), gold (35.5%) fragrance-mix (17.4%) and nickel (15.5%). The majority of the carvone-sensitized patients with allergy to gold (30/49) or allergy to mercury (16/18) also had OLL. The male-to-female ratio was 1:4.75 among the carvone-sensitized patients compared to 1:2.55 in the overall test groups. Conclusions: The frequency of patients sensitized to carvone seems to correspond with previous findings. Concomitant contact allergy to gold or mercury was often associated with OLL and these patients were often referred for suspected allergy from d ental restorations. The data together with conclusions in recent reports suggests a relationship between OLL and l-carvone contact allergy. The relationship is yet unknown and needs further investigation

Revue critique des méthodes de dosage de dioxyde de soufre et des oxydes d'azote en pollution de fond

Carvone (l-carvone), a mint flavour in spearmint oil, is considered a mild skin sensitizer. Carvone-sensitization may be linked to oral/perioral signs and oral lichen planus, but studies are sparse. The prevalence of patch test reactions to carvone and relevant findings from the positive group were investigated. Records for patch-tested patients at the Malmö clinic, for the period 1996 to 2016, were studied. Carvone-positive and carvone-negative patients were compared regarding patch test data from baseline series and dental series. Dental series-tested carvone-positive patients were also compared with a matched group. A total of 147 out of 4,221 referred patients had a positive patch test to carvone. Sensitized patients had higher mean age and were primarily women; 73% had oral signs and 57% had oral lichen. Concomitant patch test reactions to gold, nickel and mercury were common. In the matched group-comparison carvone-positive patients had a higher frequency of oral lichen, but no difference was found in sensitization to gold and mercury

Increased stiffness of the abdominal aorta in women with rheumatoid arthritis.

Objective. To study the distensibility and the diameter of the abdominal aorta and the common carotid artery (CCA) in patients with rheumatoid arthritis (RA), and investigate the relation between mechanical properties of these arteries and disease severity. Methods. One hundred and one patients with RA (33 consecutive cases with extra-articular manifestations, and 68 subjects with non-extra-articular disease, matched for age, sex and disease duration) were investigated. Echo-tracking ultrasonography was used to measure stiffness and mean diameter of the abdominal aorta and the CCA. The patients were compared with healthy individuals from the corresponding age group (n=74 for measurements of the aorta, n=64 for the CCA). Predicted values for stiffness and mean diameter, based on age and sex, were calculated. Results. Stiffness of the abdominal aorta was increased in women with RA [mean percentage of predicted value (% predicted) 180; 95% confidence interval (95% CI) 150–211] but not in men (% predicted 99; 95% CI 75–122). CCA stiffness was less markedly increased, and mean diameters of the aorta and the CCA were not different from the expected. In the RA cohort, patients with extra-articular manifestations tended to have greater stiffness of the aorta (P=0.11), and disability, as indicated by a higher Health Assessment Questionnaire score, was associated with increased aortic stiffness (P=0.04). Conclusion. RA is associated with decreased distensibility of the abdominal aorta in females, and such changes seem to correlate with disease severity. We suggest that arterial stiffness is an important factor in cardiovascular co-morbidity in RA