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Voltage and Current References
Published in John D. Cressler, H. Alan Mantooth, Extreme Environment Electronics, 2017
SiGe BGR circuits are proven to be tolerant to proton-induced TID levels of up to 3 Mrad(Si) [24,25]. Shown in Figure 47.5 are also changes in the output voltage of the compensated BGR after proton irradiation with TID level of 5040 krad(SiO2). Similar to x-ray exposure, a negative shift is observed after irradiation (due to increase in base excess current); however, with the same effective TID level, degradation due to x-ray appears to be significantly larger. This difference could be attributed to the fact that at the transistor level, the increase in the base leakage current is smaller for protons than for x-rays, potentially due to dose enhancement effects after x-ray, as discussed in [22,26].
Bipolar Junction Transistor Compact Models
Published in Samar K. Saha, Compact Models for Integrated Circuit Design, 2018
In order to evaluate qb, we first determine the components of QB. For the simplicity of QB analysis, we assume that npn-BJT is in saturation, that is, VBE > 0 and VBC > 0, then Minority carriers are injected into the base both from the emitter and from the collectorFrom the charge neutrality, the total increase in the majority carriers in the base = total increase in the minority carrier concentrationSuperposition of carriers in different regions holds, that is Total excess majority carrier density = sum of the excess majority carrier density due to each junction separatelyExcess majority carrier concentration in the base = excess carriers due to the forward voltage (VBE + VBC)Depletion approximation holds
Use of brown coal ash for the amelioration of dump soils
Published in Vladimir Litvinenko, Scientific and Practical Studies of Raw Material Issues, 2019
The long-term influence of the neutralization mediums could be determined in the ameliorated sinking area, i.e. the permanent acid regeneration was softened, and there is the base excess yet. The differences of the areas ameliorated only with lime or ash are not identifiable.
Quality assessment of Major Trauma Registry of Navarra: completeness and correctness
Published in International Journal of Injury Control and Safety Promotion, 2019
Bismil Ali Ali, Rolf Lefering, Tomas Belzunegui Otano
The results suggested that case-level MTR-N data were, to a large extent, correct and complete. This finding could be explained by the strict control of the database by the supervisor of the trauma registry system. However, a high rate of missing data for base excess (76.4%) was observed. Other trauma registries have also exhibited this issue in previous research (Lefering et al., 2014). As observed in the present study, arterial base excess was measured frequently in the emergency room but not documented in the MTR-N. Almost all measurements were performed using equipment available in emergency departments, and the results had to be recorded manually. Most doctors recorded these results in patients’ medical files but in the incorrect location. Possible solutions to this issue include automatic and direct transfer of values from measuring devices to patients’ files and increasing physicians’ awareness that this parameter is important. Completely missing values (i.e. not measured and/or recorded in medical files) were observed for arterial base excess. From one perspective, hectic situations contribute to the prevention of routine measurement. From another perspective, doctors do not consider it necessary in elderly patients with ‘normal’ physiological measurements and isolated head injuries following low-level falls. However, the proportion of elderly patients with ‘normal’ physiological measurements who experienced isolated head injuries following low-level falls was 20% in the current study.
Extracellular buffer choice influences acid-base responses and gastrointestinal symptoms
Published in Research in Sports Medicine, 2021
J. Peacock, S.A. Sparks, I. Middlebrook, N.P. Hilton, D. Tinnion, N. Leach, B. Saunders, L.R. McNaughton
The use of exogenous extracellular buffering agents has been widely investigated in the literature (Matson & Tran, 1993; McNaughton, 1992; McNaughton et al., 2016) and across a range of sporting activities (Kumstát et al., 2018; Saunders et al., 2014; Shave et al., 2001). Typically, these agents have been used for their potential ergogenic effects on short duration, high-intensity exercise (Grgic, 2020). The most commonly used extracellular buffers are sodium bicarbonate and sodium citrate (Carr et al., 2011), since they have the potential to increase base excess by increasing blood bicarbonate ion (HCO3−) concentration and increasing blood pH. Many studies seeking to investigate the effects of sodium citrate and sodium bicarbonate on subsequent performance measures, often commence exercise at a standardized time of around 60–90 min post-ingestion (Kumstát et al., 2018; Schabort et al., 2000; Shave et al., 2001). This comes despite individual-level data supporting a minimum of 100–180+ minutes (Potteiger et al., 1996; Requena et al., 2005; Urwin et al., 2016, 2019) or 30–180 minutes (Gough et al., 2019, 2017; Jones et al., 2016; L.F. De Oliveira et al., 2020) in order to achieve peak alkalotic responses with sodium citrate and sodium bicarbonate, respectively. Heibel et al. (2018) have previously suggested that this peak should result in blood HCO3− concentration increases of >5 mmol-L−1 for the greatest chance of an ergogenic effect. However, the different ingestion times for sodium bicarbonate and sodium citrate are due to the longer post-ingestion time for peak pH and bicarbonate (time-to-peak) changes to occur in the blood. This is likely to be a result of the higher molecular weight of sodium citrate compared to sodium bicarbonate (NaHCO3) and this too may influence total blood HCO3− changes.
The effect of β-alanine supplementation on high intensity cycling capacity in normoxia and hypoxia
Published in Journal of Sports Sciences, 2021
Kiran Akshay Patel, Luana Farias de Oliveira, Craig Sale, Ruth M James
Hypoxia resulted in a 9.1% decrease in cycling capacity compared to normoxia, as supported in the wider literature (Deb et al., 2018a). Interestingly, exercise in hypoxia led to a similar reduction in blood pH, bicarbonate and base excess, and increase in blood lactate, as following exercise in normoxia, despite the significantly shorter exercise duration. This demonstrates the greater requirement for energy supply from anaerobic sources in hypoxia, leading to an earlier attainment of critical levels of metabolites resulting in fatigue (Kent-Braun et al., 2012). Given that this was the basis for our hypothesis (that increases in the muscle carnosine content through BA supplementation would result in significantly improved cycling capacity in hypoxic conditions compared with normoxic conditions) it is somewhat surprising that our results showed no significant effects on cycling capacity or on blood responses. Similarly, B. Saunders et al. (2014a) showed no effect of BA supplementation on repeated sprints in hypoxia, while Wang et al. (2019) showed no additional benefits of BA to a repeated-sprint training protocol performed in hypoxia. In contrast to the current study however, those previous studies employed exercise tests that were unlikely to be significantly influenced by BA supplementation (Hobson et al., 2012; B. Saunders et al., 2017b). As it stands, there is little evidence to suggest that the benefits of BA supplementation shown by several authors under normal conditions (i.e., normoxia), are evident when exercise is performed in hypoxia. It should, however, be noted that a recent study has suggested the mechanism of fatigue when exercising in a hypoxic environment may not be due to impaired motor function as a result of peripheral or central fatigue, but could be related to the hypoxia affecting areas within the brain (Mira et al., 2020). More research is warranted to determine the mechanism of fatigue in hypoxia, and whether increased muscle carnosine content via BA supplementation can lead to improved exercise capacity in hypoxia and whether these changes are similar or greater than those shown in normoxia.