Improving the productivity of the cutter-loader

The task of the conducted research is to determine the dependence of the productivity of the cutter-loader on the parameters of the engagement of the teeth of the wheel-rack mover of chainless haulage systems. To solve this problem, the dependence of the influence of the parameters of the toothed gearing of the wheel-rack mover of the chainless haulage system on the performance of the cutter-loader is found using the mathematical apparatus. The equation of the balance of the power of the cutter-loader is made, taking into account the mechanical energy input for the destruction of the formation, loading the destroyed mineral mass onto the face conveyor (relevant for cutter-loaders for excavating thin flat-lying seams) and moving the cutter-loader. The theoretical performance of the cutter-loader depends on the redistribution of the mechanical energy of the drive electric motor, aimed at the destruction of the mineral and the translational movement of the cutter-loader. The correlation of the productivity of the cutter-loader with the parameters of the engagement of the teeth of the wheel-rack mover of chainless haulage system systems is revealed. The obtained dependences of the performance of the cutter-loader allow assessing the degree of influence of the parameters of the toothed gearing of the mover of the chainless haulage system on the performance of the cutter-loader. The possibility of increasing the minute productivity of the cutter-loader by up to 20% when using a wheel-rack mover of a chainless haulage system with an optimal tooth profile is established.

Comparative effects of Venlafaxine and Alendronate on Biochemical, Bone mechanical and Anti-inflammatory properties in ovariectomized rats

The drug of choice in the treatment of postmenopausal osteoporosis is alendronate. Antidepressive agents are currently used in combination with alendronate to protect against depression and may affect the condition of osteoporosis. The aim is to study the comparative effects of venlafaxine and alendronate on biochemical, bone mechanical and anti-inflammatory properties in osteoporotic induced rats. 36 female Wistar albino rats were included (6 rats/group). Treated groups were ovariectomized bilaterally to induce osteoporosis. Rats were treated orally with alendronate (3mg/kg/day) and venlafaxine (20mg/kg/day) and combined alendronate and venlafaxine for 28 days. Body weight, serum alkaline phosphates, serum calcium, three point bending test, bone mineral mass and inflammatory cytokines The induction of osteoporosis showed significant elevated serum alkaline phosphatase, decreased serum calcium, body weight, bone mineral mass and inflammatory cytokines. Venlafaxine treatment did not ameliorate the changes in tested parameters, where at end of the experiment alendronate has significant improved with serum alkaline phosphatase, serum calcium, bone mineral mass, bone mineral density. The improvement was not affected by combining venlafaxine with alendronate whereas the venlafaxine treatment alone caused a significant deterioration of tested parameters. Venlafaxine is an anti-depressive agent that inhibits brain serotonin which leads to decrease in bone formation. Hence, from the above findings the combination of alendronate and venlafaxine showed worsen the condition of osteoporosis rats.

Effect of zoledronic acid on bone nanocomposites organization and prevention of bone mineral density loss in ovariectomized rats

Objectives Osteoporosis often occurs in individuals of different age groups, frequently during menopause and after ovariectomy. It increases the risk of pathological fractures almost twice. The aim of our research was to assess bone metabolism, nanocomposite structure of the tibia under conditions of ovariectomy and zoledronic acid treatment. Methods X-ray diffraction has been performed for nanostructure analysis of mineral crystallites and crystal lattice of hydroxyapatite in the tibia samples of ovariectomized rats with additional application of bisphosphonate zoledronic acid (0.025 mg/kg). Markers of remodeling – osteocalcin, alkaline phosphatase, tartrate resistant acid phosphatase 5b – were determined. Quantitative amount of calcium in the bones was detected by atomic absorption method. Results Zoledronic acid prevented loss of mineral mass after ovariectomy. Rats after ovariectomy, treated with zoledronic acid, showed statistically higher (р<0.05) values of crystalline phase and calcium content compared with the SHAM-surgery and ovariectomy groups (р<0.05). Zoledronic acid inhibited bone remodeling, which is proved by tartrate resistant acid phosphatase 5b reduction and inhibition of osteoclasts during the experiment. Conclusions These results enable to suggest that zoledronic acid can improve mineral mass of the bone during menopause in individuals of different age groups.

A Dynamic Model of Calcium Metabolism for Predicting the Effects of Treatments on Bone Mineral Mass in Young Growing Rats (P24-046-19)

Objectives Quantifying the long-term effects of nutritional or drug treatments on bone is challenging due to the delay in time between treatment and changes in bone mass. The objective of this study was to develop a dynamic (non-steady state) mathematical model of calcium metabolism in young growing rats as an analogue for human adolescents and to use that model to predict the effects of treatments on calcium mass in bone. Methods A dynamic model of calcium metabolism was developed using kinetic data collected from Sprague-Dawley male rats (n = 54) dosed intraperitoneally with 50 μCi of 45Ca at 4 wk of age. Total calcium and 45Ca levels measured in serum and 24-h urine samples collected periodically for 45 d after treatment were analyzed by compartmental modeling using WinSAAM software. Concurrently, tracer (45Ca) and tracee (total calcium) models, together called the ‘dynamic model’, were developed. Growth of the rats was modeled using a formula based on body weight. Calcium absorption was decreased by about 50% at wk 6 to account for the reduction in bone mineral accretion in late puberty. During the first 40 d after weaning, the model included a 4-fold decrease in bone resorption and a 20-fold decrease in bone formation, consistent with previous findings of studies conducted in growing rats. Data were fitted by iterative least squares regression analysis. To mimic the effects of dietary and drug interventions during adolescence, the absorption efficiency was manipulated in terms of degree, timing, and duration and the subsequent changes in bone mass were quantified. Results The dynamic model predicted that, if absorption decreased by 25% instead of 50% during growth, the rate of bone accretion would be 32% higher and the bone mineral mass at d 50 would be 24% larger, suggesting that a dietary or drug intervention that minimizes the drop in absorption, would result in a higher bone mineral mass. Conclusions A dynamic model of calcium metabolism during growth was developed and used to predict the effect of interventions on bone mass. These predictions would be tested in future studies. Funding Sources Purdue University Graduate School and Amgen, Inc., Thousand Oaks, CA.

Validation of rapid 4-component body composition assessment with the use of dual-energy X-ray absorptiometry and bioelectrical impedance analysis

Background The 4-component (4C) model is a criterion method for human body composition that separates the body into fat, water, mineral, and protein, but requires 4 measurements with significant cost and time requirements that preclude wide clinical use. A simplified model integrating only 2 measurements—dual-energy X-ray absorptiometry (DXA) and bioelectrical impedance analysis (BIA)—and 10 min of patient time has been proposed. Objective We aimed to validate a rapid, simplified 4C DXA + BIA body composition model in a clinical population. Design This was a cross-sectional observational study of 31 healthy adults. Participants underwent whole-body DXA, segmental BIA, air displacement plethysmography (ADP), and total body water (TBW) measurement by deuterium (D2O) dilution. 4C composition was calculated through the use of the Lohman model [DXA mineral mass, D2O TBW, ADP body volume (BV), scale weight] and the simplified model (DXA mineral mass and BV, BIA TBW, scale weight). Accuracy of percentage of fat (%Fat) and protein measurements was assessed via linear regression. Test-retest precision was calculated with the use of duplicate DXA and BIA measurements. Results Of 31 participants, 23 were included in the analysis. TBWBIA showed good test-retest precision (%CV = 5.2 raw; 1.1 after outlier removal) and high accuracy to TBWD2O [TBWD2O = 0.956*TBWBIA, R2= 0.92, root mean squared error (RMSE) = 2.2 kg]. %Fat estimates from DXA, ADP, D2O, and BIA all showed high correlation with the Lohman model. However, only the 4C simplified model provides high accuracy for both %Fat (R2 = 0.96, RMSE = 2.33) and protein mass (R2= 0.76, RMSE = 1.8 kg). %Fat precision from 4C DXA + BIA was comparable with DXA (root mean square-SD = 0.8 and 0.6 percentage units, respectively). Conclusions This work validates a simplified 4C method that measures fat, water, mineral, and protein in a 10-min clinic visit. This model has broad clinical application to monitor many conditions including over/dehydration, malnutrition, obesity, sarcopenia, and cachexia.

METHOD OF PAINT COAT DURABILITY ASSESSMENT EXPOSED TO MINERAL MASS

This study analyses issues concerning defects of passive paint coats. Four reasons of their occurrence have been identified: constructional, technological, operational, and caused by wear and tear. Standardized methods of paint coat assessment are discussed based on the impact of mechanical factors (PN-EN ISO 2409:2013-06, ASTM D3359-17, PN-EN ISO 1522:2008, PN-EN ISO 4624:2016-05, PN-EN ISO 1518-1:2011, PN-EN ISO 16276-2:2008, PN-EN ISO 6272:2011, PN-EN ISO 6860:2006, PN-EN ISO 2815:2004, PN-EN ISO 1519:2000). The original method of paint coat durability evaluation is presented with the consideration of synergetic impact of mechanical forces. This method permits carrying out testing in conditions close to those during normal service. The testing stand equipped with a rotating drum filled with mineral mass has been described as well as the optical method of assessing paint coat quality using original software developed by authors. Tests for three coating systems were carried out in order to present the possibilities of the developed method. In summary, the conclusions relating to the presented testing method are presented.