Assessment of mental workload and its association with work ability in control room operators

Background:Modern technology has reduced physical workload and imposed high mental workload on the control room operators in industrial settings. The present study was conducted among control room operators to assess their mental workload, investigate their workability, examine the relationship between mental workload and workability, and determine the factors associated with workability.Methods:This cross-sectional study was carried out among 213 control room operators in six Iranian process industries. Task Load Index (NASA-TLX) was used to assess the mental workload, and Work Ability Index (WAI) was used to determine workability. The relationships between demographic characteristics and dimensions of mental workload and workability were examined by univariate tests. Logistic regression analysis was also used to determine the factors associated with the operators’ workability.Results:The results showed a high mental workload in the study population (82.38±8.8). Yet, the operators showed a good and excellent level of workability (56.4%). Pearson’s correlation coefficient revealed a significant inverse linear relationship between the mean score of mental workload and workability (r=-0.581). Besides, regression modeling demonstrated that mental demand (OR=0.90), temporal demand (OR=0.90), effort (OR=0.91), frustration (OR=0.92), from NASA-TLX subscales were significantly associated with workability. Moreover, mental and temporal demands were important factors associated with reduced workability.Conclusion:Monitoring tasks imposes high mental workload on the control room operators, which may result in adverse effects on their workability as well as on the safety of the system.Key words: Mental workload, NASA-TLX, work ability, control room     

SDH-deficient renal cell carcinoma – clinical,pathologic and genetic correlates: a case report

Background

Succinate dehydrogenase (SDH)- deficient renal cell carcinoma (RCC) is a newly identified rare subtype of RCC, having only gained acceptance from the World Health Organization in 2016. To the best of our knowledge, there are only 55 reported cases worldwide. Here, we report a new case of SDH-deficient RCC.

Case presentation

A 49-year-old male patient was incidentally found to have a large right renal mass. He had no personal or family history of paragangliomas (PGL), pheochromocytomas (PC), or gastrointestinal stromal tumors (GIST). The neoplasm was unilateral and unifocal. He underwent an open partial nephrectomy. Detailed pathological analysis was conducted to confirm the diagnosis. Genetic testing revealed a pathogenic mutation in the SDHB gene. He has been followed for 24?months now and has remained well without any evidence of local or distant recurrence. In this report we describe our experience with this diagnosis and review the relevant clinical, pathological, and genetic features.

Conclusions

Without the identification of SDHB deficiency, this patient’s personal and familial predisposition to PC, PGL, GIST and metachronous RCCs may have gone undetected despite his RCC diagnosis. When faced with an eosinophilic RCC, pathologists should routinely search for vacuoles or flocculent cytoplasmic inclusions. When these are present, or in cases of difficult eosinophilic renal tumors, staining for SDHB is recommended. For tumours without adverse pathologic features (i.e. high nuclear grade, coagulative necrosis, or sarcomatoid differentiation) excision alone may be a reasonable option, with the addition of regular surveillance for PC and PGLs in those found to harbor germline SDH mutations.

     

Engineering Analysis of Tricuspid Annular Dynamics in the Beating Ovine Heart

Functional tricuspid regurgitation is a significant source of morbidity and mortality in the US. Furthermore, treatment of functional tricuspid regurgitation is suboptimal with significant recurrence rates, which may, at least in part, be due to our limited knowledge of the relationship between valvular shape and function. Here we study the dynamics of the healthy in vivo ovine tricuspid annulus to improve our understanding of normal annular deformations throughout the cardiac cycle. To this end, we determine both clinical as well as engineering metrics of in vivo annular dynamics based on sonomicrometry crystals surgically attached to the annulus. We confirm that the tricuspid annulus undergoes large dynamic changes in area, perimeter, height, and eccentricity throughout the cardiac cycle. This deformation may be described as asymmetric in-plane motion of the annulus with minor out-of-plane motion. In addition, we employ strain and curvature to provide mechanistic insight into the origin of this deformation. Specifically, we find that strain and curvature vary considerable across the annulus with highly localized minima and maxima resulting in aforementioned configurational changes throughout the cardiac cycle. It is our hope that these data provide valuable information for clinicians and engineers alike and ultimately help us improve treatment of functional tricuspid regurgitation.     

Femoral Strength Changes Faster With Age Than BMD in Both Women and Men: A Biomechanical Study

Although a large number of studies have addressed the age‐related changes in bone mineral density (BMD), there is a paucity of data for the assessment of femoral strength loss with age in both genders. We determined the variation of strength with age in femurs of women and men by mechanical tests on a cohort of 100 cadaveric femurs. In addition, the age‐related neck BMD loss in our cadaveric cohort was found to be similar with BMD loss of four published population‐based studies. Given the strong correlation found in our cadaveric study between BMD and femoral strength, we also estimated the femoral strength of the four populations based on their reported neck BMDs. Our study showed that men's femurs in our cadaveric cohort were stronger than women's femurs by about 800 N at the same BMD level, and by 1750 N at the same age. The strength differences were not explained satisfactorily by the size difference between men's and women's bones. Similar to the findings of clinical studies, the BMD values of men at all ages were larger than that of women. The age‐related loss rates in BMD and strength were not statistically different between the two genders of our cadaveric cohort. After normalization, strength decreased more than 40% faster than BMD. On average, men reached a certain BMD value about 16 years later than women, and for strength about 23 years later, which may explain the higher rate of hip fracture in postmenopausal women. In patient population cohorts men reached a similar BMD value about 16 to 25 years later than women, whereas for estimated strength, sometimes more than 40 years later. © 2015 American Society for Bone and Mineral Research.     

Impact of silymarin on cadmium-induced apoptosis in human spermatozoa

Oxidative stress-induced apoptosis in spermatozoa may lead to male infertility. Environmental pollutants and heavy metals such as cadmium cause harmful effects on the reproductive system and sperm parameters through the induction of oxidative stress. Silymarin, as a potent antioxidant, is able to inhibit oxidative stress. This study was performed to investigate the protective effects of silymarin on cadmium-induced toxicity in human spermatozoa. Sperm samples were divided into the following five groups: (a) spermatozoa at 0 min, (b) spermatozoa in the control group, (c) spermatozoa treated with cadmium chloride (20 μM), (d) spermatozoa treated with silymarin (2 μM)+ cadmium chloride (20 μM) and (e) spermatozoa treated with silymarin (2 μM). Sperm parameters related to apoptosis, such as DNA fragmentation, nucleus diameter, mitochondrial membrane potential (MMP) and expression of caspase-3, were evaluated in all groups. After 180 min, spermatozoa treated with cadmium chloride showed a significant decrease in nucleus diameter and MMP but a significant increase in DNA fragmentation; however, caspase-3 expression remained unchanged. At this time point, silymarin in the silymarin + cadmium chloride group could significantly reverse the adverse effects of cadmium chloride on these parameters.Silymarn could partly compensate for the caspase-independent apoptosis in the spermatozoa. Therefore, oxidative stress could be a consequence for cadmium toxicity.