Radiation Toxicity
Frank A. Barile in Barile’s Clinical Toxicology, 2019
The extent of solar injury depends on the type of UV radiation, the duration and intensity of exposure, clothing, season, altitude and latitude, and the amount of melanin pigment present in the skin. In fact, individuals differ greatly in their response to sun. Fair-skinned persons have fewer melanin-producing cells. Consequently, they are more sensitive to UV rays than people of dark-skinned races, although the skin of the latter is still reactive and can become sunburned with prolonged exposure. Also, the harmful effects of UV rays are filtered out by glass, smog, and smoke but enhanced by reflecting off snow and sand. The indiscriminate use of chlorofluorocarbons in aerosol propellants depletes the UV-blocking properties of ozone in the stratosphere, thus allowing a greater intensity of UV rays to penetrate through the protective upper atmospheric layers.
International public health
Siân Griffiths, Davide J Hunter, Sir Kenneth Calman in New Perspectives in Public Health, 2017
One of the ways that it can act is by facilitating agreement on international treaties. The 1987 Montreal Protocol began the process of phasing out the use of chlorofluorocarbons. Although it will be several decades before the benefits are fully apparent, this has at least arrested the process of damage to the earth’s ozone layer. Fifty years after the end of the conflict, Second World War landmines continue to maim and kill people in North Africa and South-East Asia. Consequently, the benefits that will arise from agreement on a Landmine Treaty will also take decades to have their full effect but at least it will prevent the situation in many parts of the world from getting worse. Most recently, governments came together within the World Health Organization to agree the Framework Convention on Tobacco Control, the first ever treaty where the primary aim was the improvement of health. It requires governments to enact a package of measures that include imposition of restrictions on tobacco advertising, sponsorship and promotion, strengthening health warnings, reducing exposure to second-hand smoke, and clamping down on tobacco smuggling (www.fctc.org/). In these ways it will, over time, save millions of lives.
Environment and health
Liam J. Donaldson, Paul D. Rutter in Donaldsons' Essential Public Health, 2017
The ozone layer constantly passes through natural cycles. At some periods, it thins only then to replenish itself. In the last 30 years, much scientific attention has focused on so-called ozone-depleting substances that destroy the ozone layer to the extent that natural processes cannot heal it. Chief among these are chlorofluorocarbons (CFCs), but there are many others. They had become firmly established in products that were highly successful adjuncts to modern living, such as refrigerator coolants, aerosols and some other solvents. Ultraviolet light interacts with these products and chlorine atoms are released. There is then no natural process to break them down as they drive up into the stratosphere. One chlorine atom destroys 100,000 molecules of ozone. Most concern has been concentrated on the Antarctic, where a so-called ‘hole’ in the ozone layer developed. The low temperatures in this region speed up the conversion of chlorofluorocarbons to chlorine atoms. The hole is not a true gap in the ozone layer, but rather a substantial reduction in its thickness. International agreements, such as the Montreal Protocol, have sought to phase out chlorofluorocarbon-based products. This has been a successful demonstration of collaborative international action – so much so that scientists monitoring the ozone layer report some recovery of the previous damage, but estimate a further 50 years for it to be made good, provided that there is no reversal.
Detrimental effect of UV-B radiation on growth, photosynthetic pigments, metabolites and ultrastructure of some cyanobacteria and freshwater chlorophyta
Published in International Journal of Radiation Biology, 2021
Mostafa M. El-Sheekh, Eman A. Alwaleed, Aml Ibrahim, Hani Saber
Ultraviet radiation (UV) is emitted from the sun and divided to three wavebands; UV-A has wavelengths between 320–400 nm and is not screened out by the molecular oxygen (O2) and the ozone layer, UV-B has wavelengths between 280–320 nm and is usually reflected by ozone layer, and the most harmful, UV-C is entirely screened out by a combination of molecular oxygen and ozone layer (Yongji et al. 2018). So, the ozone layer is vital to natural life in the globe because of their function in absorption of UV radiation. Additional UV radiation has been entered to the earth biosphere due to depletion in this protective layer. The depletion of ozone layer induced by substances such as chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) (the United States Environmental Protection Agency 2008). Increased UV levels resulted in climate change and is portend to alteration in weather and growth patterns on the earth (Bi and Zhang 2007). Atmosphere pollution as a result of rapid industarlization is the main reason for depletion in this protective ozone layer (Björn 2007). The Antractic ozone hole is the most spectacular example for this depletion (Björn 2007). During 1997 to 2000, at northern multitudes, ozone level depletion was around 6% in relation to 1980 levels, which could cause an increase in UV-B up to 12% (McKenzie et al. 2003; Arróniz-Crespo et al. 2008). So, the influence of UV radiation on life form became a critical affair over the past three decades and could also be vital in the years to come.
A technology evaluation of CVT-301 (Inbrija): an inhalable therapy for treatment of Parkinson’s disease
Published in Expert Opinion on Drug Delivery, 2021
Michael M. Lipp, Anthony J. Hickey, Robert Langer, Peter A. LeWitt
Nebulizers have been available since the beginning of the twentieth century for pulmonary drug delivery. Most inhaled proteins for clinical development have been developed as liquids for use in nebulizers. Modern inhaler therapy has its origins in treating asthma with pressurized metered-dose inhalers (pMDIs) [15,16]. The commercial dominance of pMDIs was first challenged when chlorofluorocarbon (CFC) propellants were subject to international control and ultimately phase-out through the Montreal Protocol in 1987 [17]. The difficulty of reformulation of inhaled drugs for alternative propellants and the concurrent demand for alternative delivery systems for the products of biotechnology prompted development and use of dry powder inhalers (DPIs) [16].
Long-term safety and efficacy studies of epinephrine HFA metered-dose inhaler (Primatene® Mist): a two-stage randomized controlled trial
Published in Journal of Asthma, 2021
Edward M. Kerwin, Donald P. Tashkin, Phillip E. Korenblat, Leon S. Greos, David S. Pearlman, George W. Bensch, S. David Miller, Tony Marrs, Mary Z. Luo, Jack Y. Zhang
Epinephrine metered dose inhaler (MDI) has been used effectively as an over-the-counter (OTC) asthma medication for over 50 years with a well-established safety profile. Traditionally, these inhalers utilized chlorofluorocarbon (CFC) as its propellant. However, due to the ozone-depletion by CFC substances (1), epinephrine CFC MDIs were withdrawn from the market in December 2011.
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