The cardiac cycle
Neil Herring, David J. Paterson in Levick's Introduction to Cardiovascular Physiology, 2018
The volume of blood in a ventricle at the end of its filling phase is called the end-diastolic volume (EDV). The EDV is typically ~120 mL in a standing man (Figure 2.5), and ~150 mL supine. The corresponding end-diastolic pressure (EDP) is just a few mmHg. EDP is a little higher on the left side than on the right (Table 2.1), because the thicker left ventricle wall requires a higher pressure to distend it. Since pressures are higher in the left atrium than right atrium, congenital defects in the atrial septum in neonates usually result in a left-to-right flow of blood. Such defects do not, therefore, deoxygenate the arterial blood or cause ‘blue baby syndrome’.
Pollution assessment and estimation of the percentages of toxic elements to be removed to make polluted drinking water safe: a case from Nigeria
Published in Toxin Reviews, 2023
Johnbosco C. Egbueri, Daniel A. Ayejoto, Johnson C. Agbasi
The NO3− concentrations in the water resources were found to be below the standard limit (10–15 mg/L) set by NIS (2007) and the WHO (2017), ranging from 0 to 18.481 mg/L, with an average of 1.962 mg/L. This is likely due to the excessive use of nitrate fertilizer or other agricultural practices in the surrounding agricultural lands, as well as significant surface runoff from agricultural fields to wetlands. Anthropogenic sources such as poor management of organic wastes, sewage, and nitrogen-rich fertilizers are frequently blamed for NO3 pollution, which usually results in an outbreak of methemoglobinemia (blue-baby syndrome), goiter, and gastric cancer (Karanth 1987, Fewtrell 2004, BIS (Bureau of Indian Standards) 2012, Wagh et al.2017, 2019, Egbueri 2019, Latif et al.2020, Sahoo and Khaoash 2020). As a result, it is recommended that the hygiene of the environment in these areas be improved. In general, because of their high concentrations, several PTAs have been found to represent a substantial health concern to water users around the world. The PTAs chosen for this investigation, however, were determined to be moderate in general. All of the PTAs were found to be below their respective criteria, according to the data (Table 1).
The rumen microbiome: a crucial consideration when optimising milk and meat production and nitrogen utilisation efficiency
Published in Gut Microbes, 2019
Chloe Matthews, Fiona Crispie, Eva Lewis, Michael Reid, Paul W. O’Toole, Paul D. Cotter
The rumen has the ability to reduce nitrate to nitrite and nitrite to ammonia. Conversion of nitrate to ammonia leads to an increase of nitrogen available for use by the rumen microbes.103 It is thought that feeding nitrate to dairy cows may be an alternative method of reducing methane emissions by suppressing methanogenesis in the rumen. This is because, thermodynamically, nitrate and nitrite reduction to ammonia is a preferred reaction compared to the formation of methane with CO2 as an electron acceptor, consuming electrons at the expense of methanogenesis. Recent studies have investigated the use of 3-Nitrooxypropanol (3NOP) to inhibit methane production.104,105 In a study carried out by,105 rumen methane emissions were decreased linearly by 30% through the use of 3NOP, while increasing milk protein and lactose yields. Animal performance also increased, suggesting that energy previously wasted through the production of methane was instead used by the host to increase body weight. It is also important to note that the inhibitory effect continued over the 12 week period of the trial, thus suggesting this is a means of effective methane mitigation which can be applied to the livestock industry. Although evidently an exceptional means of reducing methane emissions, the safety of 3NOP is questionable in terms of milk processing due to fears that excess nitrate passing from the rumen to the host could result in trace amounts of nitrate being found in the milk. Trace amounts are often not a concern but, with most milk being processed for use as milk powders, nitrate may become concentrated after drying stages, and even more cause for concern is the use of these powders for baby formulas where nitrate can cause methemoglobinemia or “Blue Baby Syndrome”. Therefore, a need for more comprehensive studies on milk produced by animals on 3NOP will need to be carried out in order to certify the safety of end products.
Hydrogeochemical characterization, multi-exposure deterministic and probabilistic health hazard evaluation in groundwater in parts of Northern India
Published in Toxin Reviews, 2023
Herojeet Rajkumar, Pradeep K. Naik, Gagandeep Singh, Madhuri Rishi
NO3- contaminant in groundwater is a worldwide environmental concern due to its unique properties, such as high movability and solubility rate, stable oxidative state in water and associated health risks (WHO 2008, Zhai et al.2017, He et al. 2022a). Groundwater pollution due to NO3- is widely reported in various countries, namely in Loess plateau, Northwest China (Li et al.2019b), Matanza-Riachuelo River Basin, Argentina (Ceballos et al.2021), Weining plain and Yinchuan plain, Northwest China (He et al.2022a, 2022b), Donsheng district, Inner Mongolia (Feng et al.2020), Gorveh-Dehgelan, Western Iran (Rahmati et al.2015), Catalan Region, Spain (Carrey et al.2021) and Guanzhong plain, China (Wang and Li 2022). In India, ∼118 million people consume water with NO3- content 45–100 mg/L, and ∼108 million people drink water containing NO3- level >100 mg/L (Rai 2003, Sangwan et al.2021). Anthropogenic activities, such as application of N-chemical fertilizers (Huang et al.2011), excreta from animals farm (Minet et al.2017, Zhang et al.2018), urban runoff (Lapworth et al.2017), landfill leachate (Rao et al.2021), wastewater irrigation (Elisante and Muzuka 2017) and discharge of untreated municipal, sewage and industrial effluents (Herojeet et al.2016, He et al. 2022a), are the leading causes for NO3- loads. The acute toxicity of NO3- is often encountered even though the concentration level for drinking water is below 45 mg/L in infants (<1 year) and children by “blue baby syndrome” (Skold et al. 2011, BIS 2012). Long-term exposure to NO3- has chronic effects on human health, such as non-Hodgkin lymphoma, nitrosamines, and multiple sclerosis (Fabro et al.2015, Wongsanit et al.2015). Therefore, the health hazard risks of such ions are still concerns to infants and children even at low concentration due to exposure dose, sensitivity and weak tolerance limit (Adimalla and Qian 2019).
Related Knowledge Centers
- Acute Respiratory Distress Syndrome
- Chest Radiograph
- Congenital Heart Defect
- Nitrate
- Methemoglobinemia
- Cyanosis
- Cyanotic Heart Defect
- Methemoglobin
- Pit Latrine
- Tachypnea