Radionuclide Transport Processes and Modeling
Michael Pöschl, Leo M. L. Nollet in Radionuclide Concentrations in Food and the Environment, 2006
Estuaries are complex transition zones between rivers and seas. They present various morphological types which reflect their genesis (e.g., deltas, fjords …) and are characterized by two-way water flow: (1) a one-way freshwater flow and (2) a reversing two-way tidal circulation. The changing pattern of water circulation in the estuary and its morphology define the water mixing patterns between freshwater and seawater. Based on their mixing patterns, estuaries are classified into three categories: Poorly mixed: saltwater flows upstream below the downstream freshwater flow, creating a steep vertical salt gradient with practically no horizontal salinity gradient.Partially mixed: stronger tidal currents cause mixing between fresh- and saltwater, giving rise to both marked vertical and horizontal gradients.Well mixed: strong tidal currents induce enough turbulence to achieve complete mixing between fresh- and saltwater, resulting in the absence of a vertical gradient and leaving only a horizontal salinity gradient increasing toward the open sea.
An Outbreak of Cryptosporidium sp. Associated with a Public Swimming Pool
Meera Chand, John Holton in Case Studies in Infection Control, 2018
Most water disinfection processes do not kill Cryptosporidium. It is resistant to normal chlorine levels used for swimming pool disinfection. Therefore, filtering is required to remove the parasite. Swimming pool outbreaks are often associated with mismanagement and inadequate pool water filtration. Swimming pool operators should ensure that filters are operating well and with coagulant, that there is sufficient water replacement (particularly in periods of high bather load), that they conduct filter backwashing appropriately and after the pool has closed at night, and that they encourage preswim showering, and that babies and toddlers wear special swim nappies (diapers). UV light, which inactivates Cryptosporidium oocysts, plays an adjuvant role in Cryptosporidium disinfection in a minority of newer pools. Risks to public health can be minimized by ensuring swimming pool construction, engineering, management, procedures and pool water circulation, and treatment and disinfection are optimal and in accordance with current guidelines.
Disaster Concepts and Trends
Emily Ying Yang Chan in Public Health Humanitarian Responses to Natural Disasters, 2017
CRED classifies natural disasters into six major subcategories (see Figure 2.2): Geophysical: Events originating from solid earthMeteorological: Events caused by short-lived/micro-scale atmospheric processesHydrological: Events caused by deviations in the normal water cycle and/or overflow of bodies of water caused by windClimatological: Events caused by long-lived/meso-to macro-scale processesBiological: Disasters caused by the exposure of living organisms to germs and toxic substancesExtraterrestrial: A hazard caused by asteroids, meteoroids and comets as they pass near earth or strike earth, or any changes in interplanetary conditions that affect earth’s magnetosphere Climatological, hydrological and meteorological disasters may be grouped together as hydro-meteorological disasters. Together with biological disasters, they are natural disasters with direct associations with the climate system; their occurrence and intensity are affected by global climate change.
Temperature control and intermittent time-set protocol optimization for minimizing tissue carbonization in microwave ablation
Published in International Journal of Hyperthermia, 2022
Xiaofei Jin, Yu Feng, Roujun Zhu, Lu Qian, Yamin Yang, Qindong Yu, Zhihan Zou, Weitao Li, Yangyang Liu, Zhiyu Qian
The output power of the microwave generator ranges from 1 to 150 W. The microwave antenna (KY-2450-B1) is 150 mm in length and 1.9 mm in diameter. The microwave antenna has a built-in water-cooling circulation pipe. The normal saline is pumped into the circulation pipeline through a water pump and can flow to a position 1 cm away from the connection between the needle rod and the puncture needle (microwave radiation point). The water circulation flow rate is 30 ml/min, and the average water temperature before and after the circulation is about 25 °C and 28 °C, respectively. The thermoprobe is 130 mm in length and 1.2 mm in diameter, which can measure temperature changes between 0 and 200 °C. The temperature sensor of the thermoprobe is a packaged NTC (negative temperature coefficient) thermistor with a resistance value of 10 K, which is insulated and waterproof. The thermoprobe monitors the temperature of the microwave radiation point, the normal saline cannot flow to this position, so it does not affect the authenticity of the temperature. The main control board accompanying with the software interface allows the setting of heating parameters of microwave ablation and real-time temperature recording.
Estimates of environmental loading from copper alloy materials
Published in Biofouling, 2020
Patrick J. Earley, Brandon L. Swope, Marienne A. Colvin, Gunther Rosen, Pei-Fang Wang, Jessica Carilli, Ignacio Rivera-Duarte
The Dome-system is considered the most accurate method for estimating passive leach rates in situ from AF coatings on ships’ hulls and similar surfaces (Finnie 2006), and was expected to be the most accurate method for making similar release rate measurements from copper alloy mesh and other aquaculture materials for this study. Laboratory standard methods for release rate determination of paint systems (ASTM International (ASTM)) 2006, ASTM 2007; International Standards Organization (ISO) 2007a, ISO 2007b) are useful for understanding relative leach rates; however, it is widely recognized that these methods do not produce data representative of release rates in a natural environment for AF products, and are not suitable for deriving environmental loading estimates (Schiff et al. 2004; ASTM International (ASTM)) 2006, ASTM 2007; Finnie 2006). The Dome-system and method, in contrast, allow for testing to occur in a natural seawater environment and produce realistic environmental loading values compared to laboratory methods. This system isolates a volume of ambient water over a surface, and provides water circulation in a closed loop, thus allowing for a confined volume of ambient seawater to be exposed to leaching effects from a given surface. The system allows small aliquots of the confined seawater to be withdrawn at regular intervals, from which leachate release rates are then determined.
Splenectomy in zebrafish: a new model for immune thrombocytopenia
Published in Platelets, 2022
Uvaraj P Radhakrishnan, Ayah Al Qaryoute, Revathi Raman, Pudur Jagadeeswaran
We used the VWR Vista Vision stereo microscope with halogen and fluorescence light combination as a stage to perform the surgery for splenectomy. Adult zebrafish of 0.5 gm weight was anesthetized by placing them in 50 ml of 1 mM Tricaine until zebrafish flips sideways. It was then placed on a soft sponge that had a groove cut to accommodate the zebrafish. Water was pumped by a peristaltic pump (Cole Parmer, Chicago IL) from a beaker of water through the Tygon tubing that had the diameter slightly larger than the fish head. At the exit end of Tygon tubing, the fish head was gently inserted, such that the ventral side of the body is exposed, and there is a continuous flow of water to allow for proper ventilation. Laparotomy was performed by making about 1 cm incision in the midline of the zebrafish ventral side using a scalpel blade. By using a pair of closed forceps, the abdomen’s internal organs are gently pushed to the right side of the body, so that spleen on the left side is exposed. Using another pair of forceps that have blunt ends, the spleen was captured and gently pulled. The incision was sealed by approximating the skin and muscle followed by the addition of Vetbond (3 M Animal Care Products, St. Paul, MN) delivered by pipette tip to the area of the incision. The fish was returned to the water circulation system.
Related Knowledge Centers
- Nitrate
- Salinity
- Sedimentation
- Sublimation
- Biogeochemical Cycle
- Residence Time
- Phosphorus
- Hydrogen