Characterization of the dynamic viscoelastic response of the ascending aorta imposed via pulsatile flow.

This study characterizes the material properties of a viscoelastic, ex vivo porcine ascending aorta under dynamic-loading conditions via pulsatile flow. The deformation of the opaque vessel wall and the pulsatile flow field inside the vessel were recorded using ultrasound imaging. The internal pressure was extracted from the pulsatile flow results and, when coupled with the vessel-wall expansion, was used to calculate the instantaneous elastic modulus from a novel, time-resolved two-dimensional (i.e. axial and circumferential) stress model. The circumferential instantaneous elasticity obtained from the two-dimensional stress model was found to match the uniaxial tensile test for strains below 50%. The agreement in elasticity between the two stress states reveals that the two-dimensional stress model accurately resolves the circumferential stress of the viscoelastic aorta at physiological strains (8%-30%). At higher strains, results from pulsatile flow generated a more compliant response than the uniaxial measurements. Viscoelastic properties (storage modulus and loss factor) were also calculated using the two-dimensional stress model and compared to those obtained from uniaxial tests. While instantaneous elasticity matched between the cylindrical and uniaxial loading, the viscoelastic behaviour significantly diverged between stress states. The storage modulus obtained from the pulsatile flow data was dependent on mean Reynolds number, while the uniaxial storage modulus results exhibited a strong inverse dependency on the frequency. The loss factor for the pulsatile flow data increased alongside the frequency, while the uniaxial data indicated a constant loss factor over the entire frequency range. The results of the current study show that the two-dimensional stress model can accurately extract the material properties of the ex vivo porcine aorta.

Prevalence and economic impact of cystic echinococcosis and liver fluke infections in slaughtered sheep and goat in north-central Iran, 2008-2018.

Cystic echinococcosis (CE) and liver fluke infections as important zoonotic infections impose a large socioeconomic impact on societies. As an endemic region for these infections, slaughterhouse inspections should be more considered in Iran. This study aimed to analyze the 11-year record of offal condemnation due to CE, fascioliasis, dicrocoeliasis infections in sheep and goat and its economic impact at Alborz slaughterhouse, north-central Iran. The prevalence rate was calculated as the infected organs (as nominator) divided by the slaughtered cases (as the denominator) in each year and month. The annual percent changes was used to determine trends of parasitic diseases over time. The relationship between metrological indexes and the prevalence of parasitic diseases was determined by the linear regression model. Statistical analyses were done using STATA software 14. For an estimate, the economic impact, the total numbers of offal condemnation were calculated. The overall prevalence rate of fascioliasis, dicrocoeliasis, and CE was 0.95%, 2.17%, and 12.74%, respectively. There was a declining trend in the prevalence of fascioliasis and dicrocoeliasis, whereas, the prevalence of CE increased from 7.57% in 2008 to 9.53% in 2018, representing an annual change of + 0.02%. The direct economic impact was estimated at US$ 1,670,977 and US$ 25,148 for liver and lung, respectively. The number of condemned organs due to these infections is noticeable in Alborz Province, north-central, Iran. The high economic impact of these infections showed the necessity of implementing a continuously infected animal's trace-back and disease control in the site of infection.

Prevalence and time-trend analysis of intestinal parasitic infections in north-central Iran, 2012-2016.

Intestinal parasitic infections are still considered as health challenges, predominately in the areas with low sanitation and socioeconomic conditions. Owing to the socioeconomic impact, these infections are considered as important Neglected Tropical Diseases in developing countries, including Iran. This study aimed to evaluate the prevalence and time-trend of intestinal parasitic infections in Nazarabad, Alborz Province north-central Iran. In a cross-sectional study, medical records of 4427 suspected cases of intestinal parasites, referred to the Nazarabad health network, from 2012 to 2016 were reviewed. Bio-data, as well as laboratory data, were extracted after obtaining ethics approval. The descriptive and time-trend analyses were applied to the data. Linear regression analysis was used for the time-trend analysis. The results indicated that 18.0% of the cases to have at least one parasite in their intestine. A total of 4.5% (36/798) of positive cases has mixed infection. The median age was 31 with a range from 4 to 84 years. There are 12 different parasites detected. Blastocystis (9.2%) and Giardia (7.4%) were more prevalent parasites in the cases. Time-trend analysis showed a decreasing trend of the infection from 2012 to 2016. The most prevalent infection was found in the spring months. These infections are still among the health challenges in north-central Iran. More investigations are needed to determinate the main sources of these parasites in this area. More effective control programs are needed to combat these infections, especially in the spring and summer months.

Prevalence and time-trend analysis of intestinal parasitic infections in north-central Iran, 2012-2016

@#Intestinal parasitic infections are still considered as health challenges, predominately in the areas with low sanitation and socioeconomic conditions. Owing to the socioeconomic impact, these infections are considered as important Neglected Tropical Diseases in developing countries, including Iran. This study aimed to evaluate the prevalence and time-trend of intestinal parasitic infections in Nazarabad, Alborz Province north-central Iran. In a cross-sectional study, medical records of 4427 suspected cases of intestinal parasites, referred to the Nazarabad health network, from 2012 to 2016 were reviewed. Bio-data, as well as laboratory data, were extracted after obtaining ethics approval. The descriptive and time-trend analyses were applied to the data. Linear regression analysis was used for the time-trend analysis. The results indicated that 18.0% of the cases to have at least one parasite in their intestine. A total of 4.5% (36/798) of positive cases has mixed infection. The median age was 31 with a range from 4 to 84 years. There are 12 different parasites detected. Blastocystis (9.2%) and Giardia (7.4%) were more prevalent parasites in the cases. Time-trend analysis showed a decreasing trend of the infection from 2012 to 2016. The most prevalent infection was found in the spring months. These infections are still among the health challenges in north-central Iran. More investigations are needed to determinate the main sources of these parasites in this area. More effective control programs are needed to combat these infections, especially in the spring and summer months.

Macracanthorhynchus hirudinaceus: the most common helminthic infection of wild boars in southwestern Iran.

A pathological and epidemiological study on Macracanthorhynchus hirudinaceus infection on 25 wild boars Sus scrofa in southwestern Iran was done. Overall 24 helminthes (18 female and 6 male) were collected from the intestine of 13 infected wild boars. Thus, the prevalence of acanthocephalans among the 25 examined boars was 52 %. Pathological evaluation revealed damages caused by the acanthocephalans penetrated in the small intestine tissue. Helminthes caused severe necrosis with ulcer and inflammation in tunica sub mucosa layer. High prevalence of this helminthic infection may cause severe hazard for farmers, residents and also wild life animals.