Earth's Ozone Research Articles

Acid-catalyzed phenolation of lignin with tea polyphenol: Enhancing uv resistance and oxidation resistance for potential applications

The rapid development of the industry has led to the destruction of the earth's ozone layer, resulting in an increasingly serious problem of excessive ultraviolet radiation. Exploring effective measures to address these problems has become a hot topic. Lignin shows promise in the design and preparation of anti-ultraviolet products due to its inherent properties. However, it is important to investigate way to enhance the reactivity of lignin and determine its application form in related products. In this study, phenolic reactions with tea polyphenols were conducted through acid-catalyzed conversion, utilizing organic solvent lignin as the primary material. The phenolic hydroxyl content of the original lignin increased significantly by 218.8 %, resulting in notable improvements in UV resistance and oxidation resistance for phenolic lignin. Additionally, micro-nanocapsule emulsions were formed using phenolic lignin particles as surfactants through ultrasonic cavitation with small-molecule sunscreens. A bio-based sunscreen was prepared with phenolated lignin micro-nanocapsules as the active ingredient, achieving an SPF 100.2 and demonstrating excellent stability. The sunscreen also exhibited strong antioxidant properties and impermeability, ensuring user safety. This research offers a current solution for improving the application of lignin in sunscreens while also broadening the potential uses of plant-based materials in advanced functional products.

Design of Air Blast Freezing System Using Cascade Refrigeration R290/R32 System with Capacity 5kg

Indonesia is a maritime country that has an abundance of marine catches. In 2022, the production of marine catches reached 24.85 millions tons, while the export amount was 1.221 millions tons. This is due to the limited technology that can extend the freshness of marine catches. Based on this problem, a cooling system was designed in the form of an ABF that can freeze marine catch products. The Air Blast Freezing (ABF) system is designed at an air temperature of -40oC using a cascade refrigeration system. The working fluid used is R290/R32 hydrocarbon, which has very low GWP and ODP so it is safe for the environment and the earth's ozone layer. The results obtained show that the cooling load is 444.037 Watts, the LTC compressor power and HTC compressor power are 116.19 Watts and 205.98 watts. The designed air blast freezing system has a surface area of LTC evaporator of 2.670 m2 and HTC condenser of 4.780 m2. The calculated capillary pipe length is 1.94 m for HTC and 1.51 m for LTC, the COP of the ABF system is 2.774.

Catalytic hydrolysis of monochlorodifluoromethane over ZnO/ZrO2 catalysts at low temperatures.

Monochlorodifluoromethane (HCFC-22) has been identified as a significant contributor to the depletion of the Earth's ozone layer, garnering considerable attention within the scientific community. Consequently, the investigation of Freon degradation has become a central focus of current research efforts. In this study, we opted to employ catalytic hydrolysis as it offers numerous advantages for the degradation of HCFC-22. Specifically, we prepared ZnO/ZrO2 catalysts with hexahedral rod-like structures through citric acid complexation. We examined the impact of various preparation conditions (such as the molar ratio of ZnO to ZrO2, calcination temperature, and calcination time) as well as catalytic hydrolysis conditions (including the amount of catalyst, total flow rate, and catalytic hydrolysis temperature) on the hydrolysis rate of HCFC-22. Characterization of the catalysts was performed using techniques such as XRD, SEM, EDS, TG-DTG, FTIR, N2 adsorption-desorption, CO2-TPD, and NH3-TPD. Our experimental findings revealed the optimal preparation conditions: a catalytic hydrolysis temperature of 100°C, a molar ratio of ZnO to ZrO2 of 0.7, a water bath temperature of 90°C, a roasting temperature of 400°C, and a roasting time of 4h. At a catalytic hydrolysis temperature of 100°C, the hydrolysis rate of HCFC-22 reached 99.81%, with the main hydrolyzed products being HCl, HF, and CO2.

Plum blossom low molecular weight polypeptide protects HaCaT cells against UVB-induced oxidative damage in vitro and underlying mechanism.

Increasing amounts of ultraviolet radiation occur as ozone depletion causes the earth's ozone layer to be destroyed, making antioxidant efficacy a research hotspot. Previous studies on plum blossom have mostly focused on Volatile Oils, Flavonoids, Phenylpropanoids, and other compounds, whereas few studies have focused on low molecular weight polypeptide (LMWP) of plum blossom. This research provides a reference for the deep processing and utilization of plum blossom. (a) Plum blossom low molecular weight polypeptides protect HaCaT cells against UVB-induced oxidative damage in vitro and the underlying mechanism. (b) Improve the theoretical basis for the intense processing and utilization of plum blossom. The safe concentration of LMWP and the survival rate of HaCaT cells were determined using the CCK-8 experiment. The fluorescence intensity of reactive oxygen species (ROS) was identified using the dichlorofluorescin diacetate (DCFH-DA) method; Superoxide dismutase (SOD) and malondialdehyde (MDA) concentrations were measured in ruptured cells; Western blot analysis was used to examine the expression levels of three proteins: nuclear factor E2-related factor 2 (Nrf2), heme oxygenase 1 (HO-1), and benzoquinone oxidoreductase 1 (NQO-1). It was noted that a certain concentration of LMWP could promote cell proliferation. In oxidatively damaged HaCaT cells, SOD levels and survival rates were markedly reduced, but ROS and MDA levels were elevated. However, after treatment with LMWP, the survival rate of the cells and SOD levels were markedly increased, and the levels of ROS and MDA were markedly decreased. As shown by Western blotting, the model group exhibited lower levels of Nrf2, HO-1, and NQO-1 expression than the control group, whereas LMWP-treated cells had significantly higher levels of Nrf2, HO-1, and NQO-1 expression than their model-treated counterparts. LMMP can effectively protect HaCaT cells against oxidative damage in vitro induced by UVB, and the underlying mechanism is linked to the activation of the transcription factor Nrf2.

PENGARUH PRETREATMENT BAHAN KIMA DAN BIOLOGI TERHADAP AKUMULASI VOLUME BIOGAS DARI LIMBAH MAKANAN

PENGARUH PRETREATMENT BAHAN KIMA DAN BIOLOGI TERHADAP AKUMULASI VOLUME BIOGAS DARI LIMBAH MAKANAN

DYNAMICS AND CAUSES OF ENDEMIC HUMAN DISEASES IN UKRAINE

The article describes the dynamics and causes of endemic human diseases in Ukraine. According to the results of statistical data on the dynamics of indicators of anthropogenic and technogenic load on the surrounding natural environment, the ecological situation in Ukraine is a crisis. This leads to environmental pollution with substances dangerous to human health, deterioration of the Earth's ozone layer, and also contributes to the appearance of new chemical compounds and changes the quantitative composition of existing ones.
 Endemic diseases are those that are observed in people for a long time in a certain limited territory and are caused by natural and social conditions. The occurrence and risk of development of endemic diseases is determined by the action of environmental elements, anthropotechnogenic and social factors.
 The purpose of the study was to establish the dynamics and causes of endemic diseases in the population of Ukraine during 2017-2021. It was established that endemic caries, endemic fluorosis, endemic goiter, and water-nitrate methemoglobinemia were the most common endemic diseases of the population of Ukraine during the studied years. Among all identified endemic diseases, endemic caries was recorded most often among the population, methemoglobinemia was less common. The dynamics of occurrence of the above-mentioned endemic diseases among the population during 2017-2021 increased. The causes of the development of endemic caries are the insufficient content of fluorine in the consumed water (up to 0.5 mg/l), endemic fluorosis, on the contrary, the intake of fluorine in excessive amounts (over 1.5 mg/l). Endemic goiter develops due to a lack of iodine in consumed products and water, water-nitrate methemoglobinemia – due to an excess of nitrates over 50 mg/l. Endemic fluorosis, for the most part, is characteristic of the inhabitants of the mountainous regions of Ukraine and Poltava region, endemic goiter – for the Carpathian, Carpathian and Transnistrian-Danubian regions, endemic caries and water-nitrate methemoglobinemia – for all regions of Ukraine.

Effect of Feeding Kiwifruit (Actinidia deliciosa) Extract on Survival Rate and Reproductive Organ Morphology of Fruit Fly (Drosophila melanogaster Meigen, 1830) Ultraviolet Light Irradiation

UV (ultraviolet) radiation is one of the radiations that are naturally emitted by the sun. As the result of climate changes, the earth's ozone layer changes and the UV light radiation to the earth's surface increases. The negative effect of UV radiation is increase due to the production of ROS (Reactive Oxygen Species) or free radicals in the body. UV radiation protection can be done by increasing the intake of antioxidant-rich foods as free radical inhibitors. Actinidia deliciosa or kiwifruit is a antioxidants-rich fruit including vitamin C. This research was carried out with Drosophila melanogaster as a animal model because it is easy to breed in the laboratory, has a short life cycle, and produces large numbers of eggs. Drosophila melanogaster or fruit flies are the most commonly used of animal models in the biomedical and pharmacological fields. This study aims to determine the effect of UV radiation on fruit fly survival at the larval, pupa, and imago stages and the morphology changes of male and female reproductive organs, as well as to determine the effect of feeding kiwi fruit extract on survival rate and morphology changes of male and female reproductive organs of UV irradiated fruit fly. This research was conducted by providing UV exposure treatment and without UV radiation treatment to fruit flies for 2 hours on banana and kiwi feed medium. Data analysis was carried out with the One Way Anova test followed by the Duncan test. The results showed that UV radiation could affect the survival and morphology of the reproductive organs of fruit flies. The survival rate in the control treatment was 58%, PK treatment 81%, PPUV treatment 45%, and PKUV treatment 47%.

GAUGING GREENHOUSE EMISSION THROUGH CBA, TRADE, FDI, AND POPULATION GROWTH

Introduction: Greenhouse gas emissions have a massive effect on the thinning of the earth's ozone layer, nowadays the industry is obligated to be as responsible for the process and output as possible in order to reduce carbon dioxide emissions (CO2). This study examines the implications of consumption-based accounting, trade, and foreign direct investment on greenhouse gas emissions from the least five emitters of different fuel types, according to the World Research Institute Indonesia, which are Japan, Brazil, Indonesia, Iran, and Canada from 2000 until 2020. Methods: The study employs a panel data regression using Random Effect Model-Hausman Test. Results: The findings show that foreign direct investment has a strong negative association with lowering greenhouse gas emissions. The greater the investment, the cleaner the air and atmosphere. Trade has a negative correlation with greenhouse gas emissions, this reflects increasing environmental consciousness among producers and/or increasing pressure for environmentally friendly operations from oversea. Since natural assets could convey their full economic potential on a sustainable ground. The population had a role in lowering carbon emissions as well. The results of the consumption-based emission regression show a significant positive relationship, which can clearly exacerbate climate change conditions. It is not astounding, given that CBA accounts for emissions throughout a product's or service's complete lifecycle. Conclusion and suggestion: This study advances the grasp of greenhouse gas emissions and the factors that influence others in the five lowest emitters. It is the first study towards using greenhouse gas emission data as the dependent variable, rather than consumption-based accounting data, which has been used in most previous studies.

Separation of Azeotropic Refrigerant Mixtures Using Ionic Liquids

Refrigeration and air-conditioning systems are widespread throughout modern society, from the refrigerated cold chain that provides fresh foods and storage of medicines to the air conditioning of homes and buildings. Refrigeration is viewed as one of the most transformative engineering achievements of the 20th century and the demand for cooling will continue to increase as economic conditions improve and the climate continues to warm; however, refrigerants do come with an environmental cost.In 1987, the Montreal Protocol phased out chlorofluorocarbon (CFC) refrigerants because of their high ozone depletion potential (ODP). The replacements, typically mixtures of hydrofluorocarbons (HFCs), are safe for the Earth's ozone layer, but most have high global warming potentials (GWPs). HFCs account for 7.8% of total global greenhouse gas emissions, with 63% of that from “indirect” emissions (i.e., energy for running the system). As a result, 197 countries signed the Kigali agreement in 2016 to phase out high-GWP HFCs, with the goal of reducing emissions by 80% in the next 20 years. Millions of metric tons (mts) of high-GWP refrigerants will need to be reclaimed, but there are no good methods for separating and recycling the individual components, given that many are azeotropic mixtures.Currently, there is no means of separating azeotropic HFC mixtures, and the refrigerants will ultimately have to be incinerated. The commercial HFC mixture R-410A containing 50 wt.% HFC-32 (GWP = 675) and 50 wt.% HFC-125 (GWP = 3500) is a prime example. The HFC-32 can be reused when separated in new low-GWP products such as R-454B (69 wt% HFC-32 and 31 wt% HFO-1234yf) with a 75% lower GWP than R-410A.Ionic liquids are being developed that can separate azeotropic HFC mixtures based on differences in solubility and used as entrainers in extractive distillation. This presentation will provide experimental data on the solubility of HFCs in ionic liquids that have been measured using gravimetric microbalances and modeling using the Peng-Robinson equation of state. ASPEN Plus simulations will show how a pilot process has been designed that can continuously separate azeotropic refrigerant mixtures such as R-410A.

The Role of Ultraviolet Radiation in Human Race

Ultraviolet (UV) radiation is a form of non-ionizing radiation emitted by artificial sources such as the sun and tanning beds. Although vitamin B1 in foods has some benefits for humans, including formation of D, it can also pose health risks. Beneficial effects of UV radiation include the production of vitamin D, which is essential for human health. Vitamin D helps in bone growth by absorbing calcium and phosphorus from food. Most UVC and UVB radiation is absorbed by the Earth's ozone layer, so all UV radiation received on Earth is UVA. UVA and UVB radiation affects health. Although UVA radiation is weaker than UVB, it penetrates deeper into the skin and the penetration lasts throughout the year. Because UVC radiation is absorbed by the Earth's ozone layer, it does not emit much danger. Different types of UV rays and how powerful they are. High energy UV rays are a form of ionizing radiation. They have enough energy to remove an electron (ionization) from an atom or molecule. Ionizing radiation can damage DNA in cells.

Current status and prospects of the development of hydrogen energy

Purpose. Analysis of problems and prospects for the development of methods of hydrogen extraction, review of literature and study of methods of its transportation and use of hydrogen fuel in Ukraine and the world. Methodology. To achieve the goal, the work uses an empirical method of scientific research, taking into account theoretical provisions. Findigs. Expanded and systematized methods of obtaining hydrogen using various technologies (such as extraction of green hydrogen from excess electricity from renewable sources, gasification of coking coal at high temperature, electrolysis), which allowed to create a laboratory installation, the starting material of which is distillate from mine water, for obtaining hydrogen by electrolysis. Originality. consists in the analysis and systematization of energy and environmental aspects of the use of hydrogen fuel based on general information about hydrogen energy in Ukraine and the world. The regularities of the impact of various methods of obtaining hydrogen on the environment have been established. Although hydrogen is considered ecologically clean, in the future it is necessary to consider such a problem as the strengthening of the global greenhouse effect as a result of anthropogenic activity during the mass production and use of hydrogen and the impact of this activity on the protection of the Earth's ozone layer. Practical implication. The expediency of the transition to hydrogen energy with the production of green hydrogen by electrolysis has been confirmed. Ukraine has a high potential in the field of production of ecologically clean green hydrogen using innovative technologies. The advantage of molecular hydrogen as a synthetic fuel is its high energy density, where hydrogen exceeds natural gas by 2.6 times, oil by 3.3 times, and cellulose by 8.3 times. The topical issue of the use of wind, solar and other types of energy has led to an increase in the share of alternative sources since 2007. By 2020 According to the Ministry of Energy and international partners, the potential of production and use of "green hydrogen" is a universal tool for decarbonization. The European Commission has developed a holistic strategy to support hydrogen, placing it at the heart of the EU Green Deal. Hydrogen is produced using electricity produced from renewable sources, which currently accounts for about 1% of its total production.

Evidence that the GOE was a prolonged event with a peak around 1900 Ma

The great oxygenation event (GOE), the first of two major rises in atmospheric oxygen in Earth history, was initially placed near the Archean-Proterozoic boundary (∼2500 Ma). More recently, the position of the GOE has been moved to between 2500 and 2300 Ma so as to coincide with the loss of the MIF sulfur isotope signal due to the creation of the Earth's ozone layer at that time. Here we present a revised interpretation of the history of atmospheric oxygen in the Archean and Proterozoic, based on a multi-geochemical proxy approach. Integration of a large database of analyses of redox sensitive elements in sedimentary pyrite (Se, Co, Mo), the matrix of black shales (U, Mo), and the temporal evolution of redox sensitive minerals, suggest Earth's first oxygenation was prolonged, reaching a peak between 2000 and 1700 Ma. Rather than a relatively short-lived event from 2500 to 2300 Ma, we suggest an alternative profile for Earth's atmospheric O2, i.e., an unsteady start to the rise in oxygen around 2700 Ma that undulated for approximately a billion years, reaching a peak around 1900 Ma before a plunge in the Proterozoic Eon after 1700 Ma.

Evaluating Search Methods for Identifying Candidates for Novel Biologically Inspired Sunscreens

As the Earth's ozone layer, which blocks harmful UV radiation from reaching Earth's surface, becomes thinner, sunscreens have become one the most used and most important cosmetic products in recent decades. However, UV filters (both organic and inorganic) in the current synthetic sunscreen are found to affect the marine ecosystem negatively. They pollute the marine environment and cause damage to organisms’ reproductive and digestive systems (from microorganisms to mammals). Here, we use biologically inspired design with a problem and sustainability-driven approach to identify a possible plant or animal-inspired ingredients that could be extracted and used to obtain high protection from the sun while minimizing toxicity to human skin and pollution of the marine environment. We used Google, Google Scholar, and AskNature to identify solutions and evaluate their effectiveness. While the three search methods did not differ statistically in the number of initial solutions found, Google was perhaps surprisingly the one that generated the most hits. However, in terms of the most promising solutions, AskNature generated the most. We identified nine solutions with a particularly high potential based on their UV absorption and potential for mass production for further development: raspberry seed oil, nanoparticles of ivy rootlets, cuticular wax of dwarf mountain pine, lichen extract, MAAs from cyanobacteria, MAAs from dinoflagellates, red sweat of hippopotamus, mucus from mushroom coral, and gadusol compound from marine organisms of which we found that nanoparticles of ivy rootlets, lichen extracts, and gadusol to be especially promising.

Growth rate-dependent synthesis of halomethanes in marine heterotrophic bacteria and its implications for the ozone layer recovery.

Halomethanes (e.g., CH3 Cl, CH3 Br, CH3 I and CHBr3 ) are ozone-depleting compounds that, in contrast to the human-made chlorofluorocarbons, marine organisms synthesize naturally. Therefore, their production cannot be totally controlled by human action. However, identifying all their natural sources and understanding their synthesis regulation can help to predict their production rates and their impact on the future recovery of the Earth's ozone layer. Here we show that the synthesis of mono-halogenated halocarbons CH3 Cl, CH3 Br, and CH3 I is a generalized process in representatives of the major marine heterotrophic bacteria groups. Furthermore, halomethane production was growth rate dependent in all the strains we studied, implying uniform synthesis regulation patterns among bacterioplankton. Using these experimental observations and in situ halomethane concentrations, we further evaluated the potential production rates associated with higher bacterial growth rates in response to global warming in a coastal environment within the Southern California Bight. Our estimates show that a 3°C temperature rise would translate into a 35%-84% increase in halomethane production rate by 2100. Overall, these data suggest that marine heterotrophic bacteria are significant producers of these climate-relevant gases and that their contribution to the atmospheric halogen budget could increase in the future, impacting the ozone layer recovery.

Risks to the stratospheric ozone shield in the Anthropocene : This article belongs to Ambio's 50th Anniversary Collection. Theme: Ozone Layer.

Crutzen (1974) and Crutzen and Ehhalt (1977) presented two key papers in Ambio that in Ambioexemplify how science first revealed to humankind the potential for damage to our ozone shield in the Anthropocene. Crutzen's (1974) review is a sweeping summary of the risks to the ozone layer from supersonic aircraft, chlorofluorocarbons, as well as nuclear weapons testing and nuclear war. Crutzen and Ehhalt (1977) described how the nitrous oxide produced from fertilizers could pose another threat to the stability of the stratospheric ozone layer. The two papers are part of a body of influential scientific work that led to the pioneering Montreal Protocol to Protect the Earth's Ozone Layer to phase out production of chlorofluorocarbons (in 1987), as well as national decisions that slowed or stopped production of supersonic planes (in the 1970s). They remain guideposts today for ongoing international negotiations regarding reducing emissions from fertilizer and limiting nuclear testing.

Parametrical study of the dispersion of an alternative fire suppression agent through a real-size extinguisher system nozzle under realistic aircraft cargo cabin conditions

Nearly all active fire extinguishing systems consist of injecting an agent into the space set on fire. For aircraft cargo cabins, the agent widely used up to date is Halon 1301. The FAA provides a level of safety for this fire suppression agent that needs to be used in a volumetric concentration of 6% and needs to be acting for a duration of 0.5s. On the other hand, Halon 1301 is known to contribute to the retrenchment of Earth's atmospheric ozone layer, therefore it is going to be prohibited in the incoming years. The FAA has defined an equivalent level of safety in terms of the performance of the alternative agents. In this research, two different alternative fire suppression agents and two nozzles were tested at two vessel back-pressure conditions using a new design in purpose facility and an injection system able to control the injection pressure and the injection duration (the agent injected mass) in order to satisfy the FAA performance conditions. The discharge volume is a rectangular constant volume constant pressure vessel of approximately 0.85m3 and 1.5m of length that is provided with two transparent windows of 0.75m×1.5m to ensure an optical access to study the whole agent injection and it mixing process. Liquid phase distribution of the agent injected inside the vessel is measured by means of Diffuse Back-Light Illumination (DBI) technique. Vapor phase distribution, when present, is measured through the single-pass Schlieren technique. Results show a poor performance in terms of spatial distribution (narrow jet with little atomization) of the two alternative agents injected through the nozzle actually used in the aircraft cargo cabin fire suppression systems. However, simply replacing the nozzle and using one with a swirler showed excellent performance in terms of spray penetration and spreading angle. This results ratify that the nozzles of the fire extinguisher system currently used in the aircraft cargo cabin does not work for the alternative agents tested.

Solar ultraviolet-induced DNA damage response: Melanocytes story in transformation to environmental melanomagenesis.

Exposure to sunlight is both beneficial, as it heats the planet to a comfortable temperature, and potentially harmful, since sunlight contains ultraviolet radiation (UVR), which is deemed detrimental for living organisms. Earth's ozone layer plays a vital role in blocking most of the extremely dangerous UVC; however, low frequency/energy UVR (i.e., UVB and UVA) seeps through in minute amount and reaches the Earth's surface. Both UVB and UVA are physiologically responsible for a plethora of skin ailments, including skin cancers. The UVR is readily absorbed by the genomic DNA of skin cells, causing DNA bond distortion and UV-induced DNA damage. As a defense mechanism, the DNA damage response (DDR) signaling in skin cells activates nucleotide excision repair (NER), which is responsible for the removal of UVR-induced DNA photolesions and helps maintain the genomic integrity of the cells. Failure of proper NER function leads to mutagenesis and development of skin cancers. One of the deadliest form of skin cancers is melanoma which originates upon the genetic transformation of melanocytes, melanin producing skin cells. NER is a well-studied DNA repair system in the whole skin, as a tissue, but not much is known about it in melanocytes. Therefore, this review encapsulates NER in melanocytes, with a specific focus on its functional regulators and their cross talks due to skin heterogeneity and divulging the potential knowledge gap in the field.

Miniature ultraviolet polarimeter for early deposition of the ozone layer of the Earth

The objective of the project is to create structural and functional schemes of the device, create a ground model for testing in laboratory conditions. The following methods are used: algorithmic processing of measurement results. Structural diagrams of a UV polarimeter and a functional scheme of a UV polarimeter have been developed. An operability of the device was analyzed. The developed algorithm for processing the measurement results will determine the degree of stratospheric ozone polarization. The obtained results will assess the state of Earth's ozone layer.

Vacuum Steam Treatment Eradicates Viable Bretziella fagacearum from Logs Cut from Wilted Quercus rubra.

Methyl bromide (MB) fumigation is required for U.S. Quercus log exports due to concern over unintentional spread of Bretziella fagacearum. MB alternatives are needed due to the chemical's ability to damage the earth's ozone layer. Vacuum steam (VS) is an environmentally friendly method that was evaluated for its ability to eradicate B. fagacearum in logs (24 to 61 cm diameter; 1.7 to 1.9 m long) obtained from Q. rubra that had wilted following natural infection (NI) or artificial inoculation (AI). Five replicate loads of two NI and one AI logs were VS-treated at 56°C for 30 min and 60°C for 60 min (at 5.0 cm sapwood depth). Mean frequencies of pretreatment fungus colonization ranged from 12.5 to 24.4% in NI and 29.4 to 45.6% in AI logs based on isolation from wood chips of inner and outer sapwood, respectively, of two disks per log. Frequencies of pathogen DNA detection were similar to those for isolation. No viable pathogen or its DNA were detected in posttreatment logs. Treatment times ranged from 5 to 9 h for the 56°C/30 min schedule and from 8 to 10 h for the 60°C/60 min schedule. Based on these results, VS is worthy of further development as a MB alternative.

Two decades of polar ozone research via airborne science investigations: Addressing a NASA mandate in atmospheric composition

The comprehensive investigation of polar ozone photochemistry and dynamics has required data obtained from as full a complement of available platforms as possible (ground-based, balloon, aircraft, and satellites). Perhaps the most detailed process studies have been conducted using measurements from aircraft, taking advantage of their targeting capabilities coupled with the potential for enabling measurements at high spatial and temporal resolution. The US National Aeronautics and Space Administration (NASA) conducted the first airborne science investigation of polar ozone in an effort to establish the causes of the recurring seasonal depletion of the Earth's stratospheric ozone layer over Antarctica that was identified in the mid-1980s. Subsequent airborne studies in the polar regions of both hemispheres benefitted from extensive successful collaborations among international scientists and the integration of the aircraft measurements with those obtained using ground-based, balloon-borne, and satellite instruments. This article provides an historical perspective of NASA's utilization of its airborne assets to advance our understanding of the chemical and physical processes that control the abundance of stratospheric ozone in both the Antarctic and Arctic.