Effects of increasing cold exposure on the oxygen uptake of walking unloaded and loaded.

Introduction: Cold exposure and load carriage is an understudied area. Most research shows that VO2max is generally unaffected by cold exposure, however the majority of research suggests that sub-maximal O2 consumption increases for a given workload [1]. This pilot study assessed the effects of cold on load carriage. Methods: 4 male participants (age: 21.8 ± 3.4 years, height: 182.5 ±5.0 cm, weight: 77.8 ± 13.5 kg) completed a walking protocol of ~1 hour in a range of different ambient temperatures within an environmental chamber (20 °C, 10 °C, 5 °C, 0 °C, -5 °C and -10 °C). Humidity was controlled at ~50% while altitude was 0 m (20.95% FiO2). Participants wore shorts and t-shirt for all trials. The protocol included a 15 minute rest period, unloaded walking at 4 km.hr-1 for 4 minutes at 0% and 10% gradient. The same workloads were repeated loaded (18 kg) after a 5 minute rest. Heart rate returned to resting levels before each exercise section to ensure prior activity did not influence findings. Unloaded walking was then repeated. Expired air was collected and analysed using a Cortex 3B Metalyzer (Germany). Statistical analysis was performed using SPSS version 22, with significance denoted by p < 0.05. Results: Table ​Table1 shows a significant increase in VO2 with load (p = 0.019). At all workloads, significant increases in VO2 were associated with decreasing temperature (p = 0.048). ΔVO2 values suggest that the effect of loading was consistent, regardless of ambient temperature (p = 0.997). When comparing the first unloaded exercise bout with the second, VO2 for 20 °C, 10 °C and 5 °C was similar, whereas at 0 °C and below, VO2 was higher in the second unloaded bout, but this interaction was not significant (p = 0.158)

HVOF and laser cladded Fe-Cr-B coating in simulated biomass combustion: microstructure and fireside corrosion

Biomass is often considered as a low carbon alternative to fossil fuels in the power industry. However the heat exchangers in biomass plants can suffer from chloride based aggressive fireside corrosion. A commercially available amorphous Fe-Cr-B alloy was deposited onto a stainless steel substrate by HVOF thermal spray and laser cladding. The controlled environment corrosion tests were conducted in a HCl rich environment at 700°C for 250 h with and without KCl deposits. The samples were examined with XRD, SEM and EDX mapping to understand the corrosion mechanisms. In the absence of any deposits, the amorphous HVOF coating performed very well with a thin oxide growth whereas the crystalline laser cladding suffered from ~350 μm metal loss. The scales were composed of MnWO₄, Fe₂O₃, Fe₃O₄ and Cr₂O₃. When a KCl deposit was present, the HVOF sprayed coating delaminated from the substrate and MnCl₂ was found in the scale

The Humanistic Approach to Upbringing and Education in the Creative Legacy of the Ukrainian Pedagogues of the Second Half of the 19th Century

The article is dedicated to the study of the humanistic approach to upbringing an d education in the creative legacy of the Ukrainian pedagogues of the second half of the 19 th century. Through the analysis of S. Myropolskiy’s and Kh. Alchevska’s pedagogical legacy, a world outlook position of scholars concerning humanisation of the educational process is shown. In the co urse of the research, it is found out that basis of S. Myropolskiy’s and Kh. Alchevska’s conception was formed by the principles, confirmed by humanistic pedagogy. They revealed the humane approach essence to realizing the educational process in the national school. It is established that the pedagogues considered the teacher’s personality as an important figure of the human upbringing process

Controlling rectal and muscle temperatures: Can we offset diurnal variation in repeated sprint performance?

The present study investigated whether increasing morning rectal temperatures (Trec) to resting.evening levels, or decreasing evening Trec or muscle (Tm) temperatures to morning values, would influence repeated sprint (RS) performance in a causal manner. Twelve trained males underwent five sessions [age (mean ± SD) 21.8 ± 2.6 yr, peak oxygen uptake ( peak) 60.6 ± 4.6 mL kg min−1, stature 1.78 ± 0.07 m and body mass 76.0 ± 6.3 kg]. These included a control morning (M, 07:30 h) and evening (E, 17:30 h) session (5-min warm-up), and three further sessions consisting of a warm-up morning trial (ME, on a motorised treadmill) until Trec reached evening levels; and two cool-down evening trials (in 16–17°C water) until Trec (EMrec) or Tm (EMmuscle) values reached morning temperatures, respectively. All sessions included a 3 × 3-s task-specific warm-up followed by 10 × 3-s RS with 30-s recoveries performed on a non-motorised treadmill. Trec and Tm measurements were taken at the start of the protocol and following the warm-up or cool-down period. Values for Trec and Tm were higher in the evening compared to morning values (0.45°C and 0.57°C, P < 0.05). RS performance was lower in the M for distance covered (DC), average power (AP) and average velocity (AV) (9–10%, P < 0.05). Pre-cooling Trec and Tm in the evening reduced RS performance to levels observed in the morning (P < 0.05). However, an active warm-up resulted in no changes in morning RS performance. Diurnal variation in Trec and Tm is not wholly accountable for time-of-day oscillations in RS performance on a non-motorised treadmill; the exact mechanism(s) for a causal link between central temperature and human performance are still unclear and require more research

The effect of temperature, gradient and load carriage on oxygen consumption, posture and gait characteristics

Purpose The purpose of this experiment was to evaluate the effect of load carriage in a range of temperatures to establish the interaction between cold exposure, the magnitude of change from unloaded to loaded walking and gradient. Methods Eleven participants (19-27 years) provided written informed consent before performing six randomly ordered walking trials in six temperatures (20°C, 10°C, 5°C, 0°C, -5°C and -10°C). Trials involved two unloaded walking bouts before and after loaded walking (18.2 kg) at 4 km.hr⁻¹, on 0% and 10% gradients in 4 minute bouts. Results The change in absolute oxygen consumption (V̇O₂) from the first unloaded bout to loaded walking was similar across all six temperatures. When repeating the second unloaded bout, V̇O₂ at both -5°C and-10°C was greater compared to the first. At -10°C, V̇O₂ was increased from 1.60 ± 0.30 L.min⁻¹ to 1.89 ± 0.51 L.min⁻¹. Regardless of temperature, gradient had a greater effect on V̇O₂ and heart rate (HR) than backpack load. HR was unaffected by temperature. Stride length (SL) decreased with decreasing temperature but trunk forward lean was greater during cold exposure. Conclusion Decreased ambient temperature did not influence the magnitude of change in V̇O₂ from unloaded to loaded walking. However, in cold temperatures, V̇O₂ was significantly higher than in warm conditions. The increased V̇O₂ in colder temperatures at the same exercise intensity is predicted to ultimately lead to earlier onset of fatigue and cessation of exercise. These results highlight the need to consider both appropriate clothing and fitness during cold exposure

Asbestos-related pleural and lung fibrosis in patients with retroperitoneal fibrosis

<p>Abstract</p> <p>Background</p> <p>Retroperitoneal fibrosis (RPF) is a rare fibroinflammatory disease that leads to hydronephrosis and renal failure. In a case-control study, we have recently shown that asbestos exposure was the most important risk factor for RPF in the Finnish population. The aim of this study was to evaluate the relation of asbestos exposure to radiologically confirmed lung and pleural fibrosis among patients with RPF.</p> <p>Methods</p> <p>Chest high-resolution computed tomography (HRCT) was performed on 16 unexposed and 22 asbestos-exposed RPF patients and 18 asbestos-exposed controls. Parietal pleural plaques (PPP), diffuse pleural thickening (DPT) and parenchymal fibrosis were scored separately.</p> <p>Results</p> <p>Most of the asbestos-exposed RPF patients and half of the asbestos-exposed controls had bilateral PPP, but only a few had lung fibrosis. Minor bilateral plaques were detected in two of the unexposed RPF patients, and none had lung fibrosis. DPT was most frequent and thickest in the asbestos-exposed RPF-patients. In three asbestos-exposed patients with RPF we observed exceptionally large pleural masses that were located anteriorly in the pleural space and continued into the anterior mediastinum.</p> <p>Asbestos exposure was associated with DPT in comparisons between RPF patients and controls (case-control analysis) as well as among RPF patients (case-case analysis).</p> <p>Conclusion</p> <p>The most distinctive feature of the asbestos-exposed RPF patients was a thick DPT. An asbestos-related pleural finding was common in the asbestos-exposed RPF patients, but only a few of these patients had parenchymal lung fibrosis. RPF without asbestos exposure was not associated with pleural or lung fibrosis. The findings suggest a shared etiology for RPF and pleural fibrosis and furthermore possibly a similar pathogenetic mechanisms.</p

Iatrogenic damage to the mandibular nerves as assessed by the masseter inhibitory reflex

Iatrogenic injury of the inferior alveolar or lingual nerves frequently leads to legal actions for damage and compensation for personal suffering. The masseter inhibitory reflex (MIR) is the most used neurophysiological tool for the functional assessment of the trigeminal mandibular division. Aiming at measuring the MIR sensitivity and specificity, we recorded this reflex after mental and tongue stimulations in a controlled, blinded study in 160 consecutive patients with sensory disturbances following dental procedures. The MIR latency was longer on the affected than the contralateral side (P < 0.0001). The overall specificity and sensitivity were 99 and 51%. Our findings indicate that MIR testing, showing an almost absolute specificity, reliably demonstrates nerve damage beyond doubt, whereas the relatively low sensitivity makes the finding of a normal MIR by no means sufficient to exclude nerve damage. Probably, the dysfunction of a small number of nerve fibres, insufficient to produce a MIR abnormality, may still engender important sensory disturbances. We propose that MIR testing, when used for legal purposes, be considered reliable in one direction only, i.e. abnormality does prove nerve damage, normality does not disprove it