The Decomposed Body and the Unascertained Autopsy
Julian L Burton, Guy Rutty in The Hospital Autopsy, 2010
The author has seen several cases where death was due to the deliberate inhalation of an irrespirable atmosphere, typically helium. In such cases the deceased may have constructed an elaborate device to allow inhalation of the gas. If the pathologist receives no information regarding the presence of this equipment and the associated helium gas canisters, determination of the true cause of death may be impossible. Helium is a light inert gas and not all toxicology departments are able to test samples for its presence although it is technically possible to do so (Auwaerter et al., 2007). Determination of the cause of death in such cases may rest purely on the circumstantial evidence of the scene of death. It is notable that a number of publications are readily available to the public on the Internet describing helium inhalation as a method of suicide.
The intra-aortic balloon pump: Principles and use
John Edward Boland, David W. M. Muller in Interventional Cardiology and Cardiac Catheterisation, 2019
Originally, carbon dioxide was used as the shuttle gas but now helium is used exclusively. Helium has a lower molecular weight and density, which together with a much higher viscosity to density ratio result in faster balloon inflation and deflation.7,9 The significantly lower density of helium contributes greatly to its ability to maintain a laminar flow at higher flow rates than carbon dioxide, which more readily becomes turbulent. Helium, however, has a very low solubility in blood, which creates greater problems when balloons rupture as it tends to form large bubbles that are poorly absorbed and act as large emboli. Any bubbles that do form tend to remain stable and cause prolonged vessel obstruction.32 The low molecular weight of helium also results in diffusion of very small amounts of gas through the balloon membrane. This slow gas leakage is not of clinical significance but means that the balloon needs to be refilled; most balloon pumps automatically refill the balloon to compensate for this, in some cases as frequently as every 2 hours. Just as helium leaks out of the balloon, water vapour tends to leak into the balloon and accumulate in the delivery tubing. Significant accumulation of condensate can impair gas shuttling, and for this reason most pumps have a collection and purging system to deal with this problem.11,31
Paper 4 Answers
James Day, Amy Thomson, Tamsin McAllister, Nawal Bahal in Get Through, 2014
The magnetic field is generated by a superconducting electromagnet that produces a field more than 10 000 times stronger than the earth’s magnetic field. When a magnetic field power is increased above 0.5 Tesla, power is dissipated in the windings of the magnet, resistance builds in the conducting elements and heat is produced. Superconductivity is the process of cooling metals to reduce electrical resistance. The superconducting magnet is cooled to near absolute zero by immersion in liquid helium (which has a boiling point of below 4.3 kelvin). As liquid helium is expensive, in practice liquid nitrogen is added to reduce the temperature of gaseous helium to below its boiling point. The magnet can be easily ramped down in emergency situations, rather than switched off. In a life-threatening emergency, the magnet can also be ‘quenched’, in which the coolant is vented off and the magnet may be damaged. The vent reaches extremely low temperatures and in the event of vent failure the coolant will expand, causing hypothermia and asphyxiation to anyone in the room. Note that a residual magnetic field may still be present after a quench. The cost of reactivating a magnet after a quench is considerable.
Helium inhalation injuries managed at emergency departments
Published in Clinical Toxicology, 2021
Mathias B. Forrester
Helium is a colorless, odorless, and tasteless inert gas [1]. It has a variety of uses, such as a coolant for superconducting magnets, a protective atmosphere in welding and manufacturing processes, and a buoyant gas for airships and balloons, including smaller party balloons. Helium is less dense than air. As a consequence, inhaling helium, such as from a party balloon or tank, temporarily changes the timber and tone of the human voice, resulting in a high-pitched, squeaky voice [1]. The gas also is an asphyxiant, displacing oxygen from the lungs and depriving the body of oxygen when inhaled, resulting in dizziness, loss of consciousness, headache, nausea, seizures, and coma [1–3]. Because of some of its effects, individuals may inhale helium to become intoxicated [4,5]. Deaths due to lack of oxygen, some accidental and others the result of suicide, have been reported after inhalation of helium [1,6–18].
Chemical composition, anti-toxoplasma, cytotoxicity, antioxidant, and anti-inflammatory potentials of Cola gigantea seed oil
Published in Pharmaceutical Biology, 2019
O. Atolani, H. Oguntoye, E. T. Areh, O. S. Adeyemi, L. Kambizi
The FAMEs obtained from the seed oil of C. gigantea were analyzed on gas chromatograph GC QP2010SE SHIMADZU, Japan, equipped with a silica capillary HP-5MS column (30 m by 0.32, 0.5 µm) coupled directly to a mass detector (Agilent Technology MSD). Helium served as the carrier gas. The injector was operated at 250 °C and while the detector was operated at 380 °C. The oven temperature was programmed to rise from 40 to 250 °C at a heating rate of 5 °C/min. The analyses were performed using a split mode (1:10). Scan start time-end time; 3.77–29.31 min. The instrument was calibrated using authentic samples of n-alkanes for the reliability of characterization of compounds. The mass range of the mass spectrometer was set to 45–650 m/z. The FAMEs were identified on the basis of the authentic samples previously injected in combination with the examination with individual molecular weight, mass spectra and comparison of fragmentation pattern in the mass spectrum with that of the National Institute of Science and Technology, NIST library.
Screening of analgesic activity of Tunisian Urtica dioica and analysis of its major bioactive compounds by GCMS
Published in Archives of Physiology and Biochemistry, 2018
Raouia Dhouibi, Dorsaf Moalla, Kamilia Ksouda, Maryem Ben Salem, Serria Hammami, Zouheir Sahnoun, Khaled Mounir Zeghal, Hanen Affes
Quantitative and qualitative data were determined by GC–MS. The fraction was injected onto a Shimadzu GC-17A system (Kyoto, Japan), equipped with an AOC-20i autosampler and a split/splitless injector. The column used was a DB-5 (Optima-5), 30 m, 0.25 mm i.d., 0.25 lm df, coated with 5% diphenyl–95% polydimethylsiloxane. The oven temperature operated was programed as follows: 50 °C, held for 1 min, rising at 3 °C/min to 250 °C, held for 5 min, rising at 2 °C/min to 280 °C, held for 3 min. The injection temperature and volume were 250 °C and 1.0 l, respectively. Injection mode, split; split ratio was 30:1. Carrier gas was nitrogen set at 30 cm/s linear velocity and inlet pressure of 99.8 kPa. Other operating parameters used included: detector temperature, 280 °C; hydrogen flow rate, 50 ml/min; air flow rate, 400 ml/min; make-up (H2/air), flow rate, 50 ml/min and sampling rate, 40 ms. Data were acquired by means of GC solution software (Shimadzu, Kyoto, Japan). Agilent 6890N GC was interfaced with a VG Analytical 70–250 s double-focus mass spectrometer. Helium was used as a carrier gas. The operating conditions of MS were: ionisation voltage 70 eV, ion source 250 °C. The GC was equipped with a capillary silica column with a condensed bottom of 30 cm, 0.32 mm covered with DB-5.
Related Knowledge Centers
- Inert Gas
- Radioactive Decay
- Magnetic Resonance Imaging
- Hydrogen
- Helium Cryogenics
- Cryocooler
- Lifting Gas
- Superfluidity
- Absolute Zero
- Parts-Per Notation