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Accumulation of heavy metals in tilapia fish species and related histopathological changes in muscles, gills and liver of Oreochromis niloticus occurring in the area of Qahr El-Bahr, Lake Al-Manzalah, Egypt

Yacoub Amal M., Mahmoud Soaad A., Abdel-Satar Amaal M.

Oceanological and Hydrobiological Studies

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2021

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Vol. 50, No. 1

1--15

EN

Accumulation of metals (Fe, Zn, Cu, Mn, Pb, Cd and Ni) in the muscles and gills of Oreochromis niloticus, Oreochromis aureus and Tilapia zillii was assessed based on seven locations in the Qahr El-Bahr area in Lake Al-Manzalah. The average accumulation of metals was in the following order: Tilapia zillii > Oreochromis aureus > Oreochromis niloticus. To determine the risk of fish consumption, the estimated daily intake, carcinogenic, non-carcinogenic and relative risk indices were calculated. The results indicate that the intake of individual metals through the consumption of fish is almost safe for human health, whereas the intake of combined metals poses a high potential health risk to consumers. Assessment of carcinogenic risk of Cd and Ni from the consumption of tilapia species indicates that consumers are at risk of cancer. The contribution of Pb and Cd to the overall relative risk index ranged from 34% to 41%. Of the three species studied, Oreochromis niloticus is relatively safe for consumption as it poses the least health hazard, while Tilapia zillii is more predisposed to accumulate metals in its tissues. Histopathological changes were observed in the muscles, gills and liver of Oreochromis niloticus as a result of heavy metal accumulation in these organs.

2

Which of the five classical ballet positions is the most demanding for the dancer’s body? An electromyography-based study to determine muscular activity

Gorwa Joanna, Kabaciński Jarosław, Murawa Michał, Fryzowicz Anna

Acta of Bioengineering and Biomechanics

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2020

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Vol. 22, no. 4

3--14

EN

The study aimed to determine which of the five classical ballet positions is the most demanding regarding muscular activity, values of external rotation in the hip joints, angular values of foot progression as well as the inclination (tilt) of the pelvis in the sagittal plane. Methods: In this cross-sectional study, 14 female pre-professional ballet dancers (aged 11–16) participated. Participants were tasked with the sequential adoption of five classical ballet positions (CP1–CP5). The electromyographic activity of the muscles of the trunk and the lower limb was recorded with surface electrodes. Kinematic data including hip and knee external rotation, foot progression angle and pelvic tilt were collected using a motion capture system. Results: Symmetric positions CP1 and CP2 were not as demanding as asymmetric CP3–CP5. Higher values of hip and foot external rotation without greater muscular effort in CP2 than CP1 was noticed. Considering asymmetric positions, CP3 did not trigger a greater activity of hip or foot muscular groups than CP4 and CP5. CP4 was characterised by the greatest pelvic anterior tilt and the lowest activity of GM in the forward lower limb. In CP5, forward lower limb entailed a higher activity of muscles supporting the foot than in the remaining positions. Conclusion: In terms of biomechanics, the most demanding classical ballet position in pre-professional dancers is CP4, followed by CP5, CP3, CP1 and CP2. This finding can be applied in educational methodology of dancers, figure skaters, synchronized swimmers, acrobatic gymnasts, rhythmic gymnasts or cheerleaders.

3

Measurement of maximal isometric torque and muscle fatigue index of the knee muscles in male athletes

Danek Janusz, Wojtasik Wojciech, Szulc Adam

Acta of Bioengineering and Biomechanics

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2019

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Vol. 21, no. 3

31--37

EN

The aim of the paper was to analyse variables related to the force and fatigue of knee muscles in the right and left lower limbs among 17 male athletes. Methods: For both muscle groups, maximal isometric torque (Fmax) was determined with the use of Biodex System 4 Pro and the values of muscle fatigue index (FATI1–3) were calculated. Results: A significant difference was observed between the groups of short- and long-distance runners in the values of all fatigue indices of knee joint extensor muscles in the right limb. In turn, between the groups of athletes who had trained for 2–4 years or for 4.5–7 years and the group who had trained for 7.5–13 years, significant differences were observed in the values of all fatigue indices of knee joint flexor muscles in the right limb. The group training for 3–12 hours per week and the group training for 12.5–18.0 hours per week in the sports club differed significantly in the value of the maximal isometric torque of knee joint flexor muscles in the right limb and in the values of some fatigue indices (FAT1, FAT3) for knee joint flexor muscles in the right limb. The study reported numerous positive correlations between the assumed characteristics and the investigated variables of knee joint extensor and flexor muscles in the right and left lower limbs. Conclusions: Athletes present certain changes in variable values and positive correlations between some characteristics and investigated variables of selected knee muscles.

4

Mercury in immature and adults Herring Gulls (Larus argentatus) wintering on the Gulf of Gdańsk area

Szumiło E., Szubska M., Meissner W., Bełdowska M., Falkowska L.

Oceanological and Hydrobiological Studies

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2013

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Vol. 42, No. 3

260--267

EN

This study presents total mercury concentrations (HgT) in selected tissues and organs (blood, muscles, liver, kidneys, feathers and claws) of the herring gull (Larus argentatus) in order to assess the environmental pollution in the coastal zone of the southern Baltic. Dead, frozen birds were collected in the vicinity of Wladysławowo between December 2009 and March 2010, an exceptionally severe winter — a total of 13 specimens; 6 adults (>4 years old) and 7 immature birds (≤4 years old). Mercury concentrations in all analyzed samples exceeded the detection limit. The lowest average concentration, at a level of 0.4 μg Hg g−1 (d.w.) was observed in the muscles of adult and immature gulls while the highest, at a level of 3.3 μg Hg g−1 (d.w), was determined in the contour of immature gulls. A significant linear correlation was found between mercury concentration in the blood and the concentration in the kidneys and liver, with the coefficients of determination at R2 = 0.87 and 0.86, respectively. This indicates that blood of birds, as a mercury carrier, may reflects the concentration of mercury in tissues and internal organs of birds and, in the case of kidneys and liver, may express long-term exposure to mercury in nourishment.

5

Fatigue independent amplitude-frequency correlations in EMG signals

Siemieński A., Kebel A., Klajner P.

Zeszyty Naukowe Katedry Mechaniki Stosowanej / Politechnika Śląska

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2006

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z. 26

315-320

EN

In order to assess fatigue independent amplitude-frequency correlations in EMG signals we asked nineteen male subjects to perform a series of isometric muscular contractions by extensors of the knee joint. Different amplitudes of the signal were due to randomly varying both the joint moment and the overall amplification factor of the EMG apparatus. Mean and median frequency, RMS and mean absolute value were calculated for every combination of joint moment and amplification at the original sampling rate of 5 kHz and at several simulated lower sampling rates. Negative Spearman and Kendall amplitude-frequency correlation coefficients were found, and they were more pronounced at high sampling rates.

6

Muskuły - nowe elementu pneumatyki w systemach montażowych.

Węsierski Ł.N.

Technologia i Automatyzacja Montażu

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2003

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nr 4

16-18

7

Finite element analysis of mandible equilibrium depending on the way of its loading and supporting

Chladek W., Żmudzki J, Lipski T.

Acta of Bioengineering and Biomechanics

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2000

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Vol. 2, nr 1

63-69

EN

Results of FEA of mandible equilibrium and mandible without one-sided support at temporoman-ibular joint were presented. Models were loaded with occlusal forces whose values were experimentally itablished. Forces of muscles were simulated by elastic supports with an assumption that reactions ould lead to active forces generated by the system of muscles.