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Adjuncts in Vitreoretinal Surgery
Published in Pradeep Venkatesh, Handbook of Vitreoretinal Surgery, 2023
Specific gravity is the density of a substance relative to the density of a reference substance [usually water for liquids and solids and air for gases]. The lower the specific gravity, the higher the tendency of a substance to float above water, and vice versa. This is the reason that silicone oil with a specific gravity of 0.97 tends to float above water while PFCL with a specific gravity of 1.7–1.9 sinks under the irrigating fluid, within the vitreous cavity. [Note that specific gravity has no units of measurement because it is the relative density of one substance against the relative density of another substance.]
Nutrition and Metabolic Factors
Published in Michael H. Stone, Timothy J. Suchomel, W. Guy Hornsby, John P. Wagle, Aaron J. Cunanan, Strength and Conditioning in Sports, 2023
Michael H. Stone, Timothy J. Suchomel, W. Guy Hornsby, John P. Wagle, Aaron J. Cunanan
The relationship between hydration state and thermoregulation is an important consideration considering that dehydration can promote feelings of fatigue, heat exhaustion, and heatstroke. During exercise, factors such as temperature, humidity, and type of clothing may all impact sweating rates. In fact, it is not uncommon to lose 2–3% of body mass, mostly water, during a typical exercise session, especially in hot environments. Researchers have reported losses of up to 8% of body mass during very long-term exercise, such as marathon running, or repeated high-intensity exercise such as fall football training when fluid replacement is inadequate (28, 175). In light of these findings, it is important to note that thirst may often lag behind the actual need for water (64). Therefore, it is important that athletes ingest fluid regularly even if they had not yet recognized their thirst as a symptom. Typically, consuming 450–600 ml (15–20 fl oz) every 30 min should provide adequate fluid replacement for both long-term exercise and prolonged intermittent high-intensity exercise such as football training. Sport scientists should note the importance of monitoring hydration to ensure proper practices. While blood measures of hydration may provide the most accurate information, they are invasive and quite expensive. Thus, additional practices such as urinary specific gravity measured by refractometry or something as simple as weighing the athlete before and after practice may provide valuable information regarding the hydration status of athletes.
Nephrology, including fluid and electrolytes
Published in Jagdish M. Gupta, John Beveridge, MCQs in Paediatrics, 2020
Jagdish M. Gupta, John Beveridge
Chronic renal failure is characterized by growth failure and anaemia. The latter is due to marrow hypoplasia. Most cases of chronic renal failure in children are due to reflux nephropathy, followed as a close second by congenital malformations. Urine analysis may show no albumin or red blood cells but specific gravity may be low in end-stage renal disease. Rejection of renal transplant is no more frequent in children than in adults. Inability to concentrate urine causes polyuritis.
Simultaneous assessment of motor and cognitive tasks reveals reductions in working memory performance following exercise in the heat
Published in Temperature, 2022
Zachary J. Schlader, Jacqueline Schwob, David Hostler, Lora Cavuoto
Height and weight were measured with a stadiometer and scale (Satorius Corp., Bohemia, NY, USA). Urine-specific gravity was measured using a handheld refractometer (Atago, Bellevue, WA). Nude body weight was measured pre- and post-exercise after towel drying. Heart rate was measured using a standard heart rate monitor (Polar Electro, Bethpage, NY, USA). Approximately 90 minutes prior to experimental testing, each subject swallowed a telemetry pill (HQ Inc., Palmetto, FL, USA) for the measurement of core temperature. This approach provides a valid measure of core temperature, particularly when drinking is prohibited [29]. Mean skin temperature was measured as the weighted average of four thermochron iButtons (Maxim Integrated, San Jose, CA, USA) using the following equation: 0.3 · (chest + triceps) + 0.2 · (quadriceps + calf) [30].
Heat acclimation does not negatively affect salivary immunoglobulin-A and self-reported illness symptoms and wellness in recreational athletes
Published in Temperature, 2022
Puck Alkemade, Nicola Gerrett, Hein A. M. Daanen, Thijs M. H. Eijsvogels, Thomas W. J. Janssen, Lauren C. Keaney
HA sessions lasted for 97 ± 4 min. Cycling during HA was performed at an average power output of 94 ± 17 W, heart rate of 132 ± 14 bpm (72 ± 7% of peak heart rate), and whole-body sweat rate of 1261 ± 433 g·h−1. Average urine-specific gravity was 1.012 ± 0.006. Resting rectal temperature was not significantly different between HST1 (37.54 ± 0.30°C) and HST2 (37.39 ± 0.38°C; t(16) = 1.90, P = 0.08), while end-exercise rectal temperature after 35 min of steady state cycling was lower in HST2 (38.08 ± 0.35°C) than in HST1 (38.24 ± 0.32°C; t(16) = 2.9, P = 0.01). End-exercise heart rate after 35 min of steady state cycling was lower in HST2 (139 ± 17 bpm) than in HST1 (147 ± 19 bpm; t(16) = 4.7, P < 0.001). Whole-body sweat rate during HST2 (1338 ± 549 g·h−1) was higher than during HST1 (1072 ± 370 g·h−1; t(16) = −4.9, P < 0.001). For more detailed heat acclimation data, the reader is referred to our previous work [36,41].
Prognostic value of baculoviral IAP repeat containing 5 expression as a new biomarker in lung adenocarcinoma: a meta-analysis
Published in Expert Review of Molecular Diagnostics, 2021
Dingxiu He, Kaisen Huang, Zongan Liang
The results of the meta-analysis are represented by forest plots. The effect size and CI of each included study are described by multiple line segments parallel to the horizontal axis, where the square represents the point estimate of the effect size, and the straight line extending on both sides of the square represents the CI of the effect response. The volume of the square represents the specific gravity of each study. The combined effect size in the forest map is represented by a diamond-shaped square, and the center is the point estimate of the combined effect size. The size of the credible interval range of the combined effect size is represented by the length of the line. The longer the line segment is, the wider the confidence interval, and the rougher the result [14].