A multi-anode proportional counter for measuring (11C) carbon dioxide in exhaled air

The field of pediatric surgery has undergone numerous changes throughout the past few years. First of all the laparoscopic surgery, introduced with reluctance because many of the instruments were not appropriate for their tiny patients. Finally, the often quoted benefits of smaller scars, less pain, and shorter hospital stays had not been shown to be true in the pediatric patient. However, in the mid 1990s, surgeons began to publish their laparoscopic pediatric cases, showing laparoscopy to be a potential alternative for these patients. When pediatric surgeons began to perform laparoscopic procedures on small children and neonates, they were often forced to use instruments designed for adult patients. In the mid 1990s, 2- and 3-mm instruments were developed, which allowed surgeons to work with greater ease in confined spaces. Around the same time, a neonatal insufflator was also developed. In contrast to adult insufflators, neonatal insufflators deliver CO2 in small, controlled puffs. This technology reduced the risk of over-insufflation that was often associated with using the oversized adult insufflators in small children. Over-insufflation can often be accompanied by a significant increase in end-tidal carbon dioxide, or the measurement of the amount of carbon dioxide in the expired air. If this is not adjusted for by the anesthesiologist, overinsufflation can lead to significant pulmonary complications in already fragile neonates. With these advances, more pediatric surgeons are expanding their repertoire of minimally invasive operations. Not only are they increasing the number of cases that can be performed laparoscopically, but they are also showing that they can be safely performed on neonates weighing 5 kg and less. In parallel the regenerative medicine was a relatively new field. This combining tissue engineering and cell transplantation, with the aim of replacing damaged tissues and organs using living cells. The regenerative medicine could lead to new ways of repairing or replacing injured organs, even during fetal development and therefore even children could benefit from this exciting field. Moreover, particularly in the field of tissue engineering, there has been a remarkable contribution from academic pediatric surgeons such as Anthony Atala and Joseph Vacanti. Congenital malformations are major causes of disease and death during the first years of life and most of the time functional replacement of the missing or damaged organ (or tissue) remains an unmet clinical need. Tissue engineering led by advances in two specific fields, cell biology and materials science, has combined to create the perfect biological substitution, while materials science and polymer generation, both of natural and synthetic origin, have had constant evolution. This thesis reports the results obtained during my PhD course in “Human, Reproduction, Development and Growth” (XXV Cycle) from 2009 to 2012. During the past 3 years I have been focused my research in these main fields following 3 lines of research: - Evaluation of changes of intestinal adaptation in animal model of short bowel syndrome and the possibility to increase the intestinal surface used a 3D scaffold as guide for the lengthening of the intestinal wall until complete absorption of the same scaffold - Study of the possibility of increase of the bladder and urethral surface used an animal model and a 3D scaffold as guide until complete absorption of the same scaffold in bladder - The standardization of laparoscopic techniques in pediatric patients by multicentric study.

BACKGROUND: Elevated levels of carbon dioxide in gym air can diminish the benefits of physical activity and pose health risks for children.. AIM: to access carbon dioxide concentration in the air of school gyms during physical education classes. MATERIAL AND METHODS: A total of 612 measurements were taken to estimate the concentration of carbon dioxide in the air. These measurements were conducted in two separate gymnasiums: in Gym 1, designated for primary classes with an area of 77 m2, and Gym 2, used by middle and high school students with an area of 293 m2. Measurements were taken at 12 different points, both around the perimeter and in the central part of each gym. The height when measuremenmts were taken ranged from 0 to 230 cm. To assess the carbon dioxide concentration in the gym air, the background level was calculated based on GOST 30494-2011 standards (761.5 ppm). Student’s t-tests for independent samples were used to compare the data. Additionally, a regression analysis was utilized to estimate the spatial distribution of carbon dioxide within the gymnasiums. RESULTS: In Gym 1, the initial concentrations ranged from 845 to 1267 ppm, slightly exceeding the expected throughput. Throughout the training session, the carbon dioxide content increased by 1.6 to 2.3 times. By the end of the session, the carbon dioxide content reached 1934 to 1948 ppm at an estimated respiration level of 1.0 to 1.9 m. In Gym 2, the carbon dioxide content increased by 1.1 to 1.2 times by the end of the class. At a height of 0.0 to 1.7 m, the concentration of carbon dioxide was measured at 1016 to 1023 ppm. CONCLUSION: After 20 minutes of training at the expected intensity, carbon dioxide levels in the air exceed not only the background level of 761.5 ppm, but also the permissible level of 1000 ppm. This study highlights the importance of daily monitoring of carbon dioxide levels in school gymnasiums during training sessions and sporting events. Such monitoring is crucial for ensuring the health and safety of students and athletes.

Introduction: A few personnel feel more tired staying and working inside submarine, as compared to ashore/outdoor spaces, or even onboard afloat platforms (ships). The microclimate onboard underwater platforms play a vital role in determining the respiratory physiology parameters of personnel onboard. There exists a felt need for deeper evidence in this regard. Aims and Objectives: This study is an effort to analyze if there exists any relationship between concentrations of respiratory gases (such as oxygen and carbon dioxide) and other parameters of submarine microclimate, on the respiratory physiology parameters (such as respiratory rate [RR] and SpO2) of personnel onboard underwater platforms. The difference in concentrations of oxygen and carbon dioxide in exhaled air of personnel both inside and outside submarine was also studied. Any difference between smokers and nonsmokers regarding this parameter was also evaluated. Materials and Methods: The study was carried out on thirty healthy volunteers posted onboard a submarine. Concentrations of oxygen and carbon dioxide in the atmosphere, as also the exhaled air, were measured using a digital gas analyzer. Humidity, temperature, and oxygen saturation were measured using digital meters. The values both inside and outside were recorded and compared. Results: There was a statistically significant difference in the temperature, humidity, and level of CO2 inside and outside the submarine. There was no statistically significant difference in level of oxygen in atmosphere, oxygen and carbon dioxide in exhaled air, RR, and SPO2 level inside and outside the submarine. Conclusion: The corrected effective temperature inside a submarine is to be measured periodically and maintained in the comfort zone. The level of CO2 should be maintained close to environmental levels.

The CO2 cycle on earth in the last 400,000 years shows that CO2 in the atmosphere increased every 80,000 years and 100,000 years on average and then dropped back later. Although there is 0-0.03% (0-300 ppm) carbon dioxide (CO2) in the air, it has a vital importance because of its amount and variety. Plants reduce the amount of CO2 in the atmosphere with photosynthesis. But plants cannot do photosynthesis in winter or night. As a result, they might have a negative impact on the amount of CO2. In this study, the amounts of air carbon dioxide are measured in forests and urban areas and evaluated depending on season and day or night. Results of our study show that, despite the amount of carbon dioxide decreases in the summer depending on the sunlight, it can double its level at night. In addition to day and night, there is a big difference between the amount of carbon dioxide in terms of summer and winter seasons.

The use of anaerobic incubation for the culture of Streptococcus pneumoniae from sputum was compared with incubation in carbon dioxide in air. A coagglutination test for pneumococcal antigen was used as an index of the number of specimens containing pneumococci. A total of 334 specimens were examined. There was evidence of pneumococcal colonisation by culture or coagglutination, or both, in 48 (14.37%), of which 41 (12.27%) yielded S pneumoniae on culture. Anaerobic incubation was better than incubation in carbon dioxide in air for the primary culture of S pneumoniae from sputum. Primary isolation of S pneumoniae was achieved in 11 of the 41 strains (26.82%) by anaerobic incubation alone, by incubation only in carbon dioxide in air in one strain (2.43%), and by both anaerobic incubation and incubation in carbon dioxide in air in 29 strains (70.73%). Anaerobic incubation gave large moist or mucoid colonies that were easy to recognise, but it suppressed the typical draughtsman colony of S pneumoniae. The factor V supplement routinely used in our medium also inhibited the formation of draughtsman colonies. It is suggested that draughtsman colonies occur because of a relative lack of the coenzyme nicotinamide adenine dinucleotide (factor V), which is required as a reducing agent in aspartate and glutamate metabolism. This nutritional deficiency may lead to bacterial cell wall defect and hence to the autolysis which gives the typical draughtsman colony.

The concentration and isotopic abundances of carbon dioxide in rural and marine air

Combined effect of carbon monoxide mixed with carbon dioxide in air on the mortality of stored-grain insects

Electrical waterbath stunning is the most common method used to stun poultry under commercial conditions. The voltage supplied to a multiple bird waterbath stunner must be adequate to deliver the required minimum current to each bird. High frequency (> 300 Hz) electrical waterbath stunning needs further investigation to determine its efficiency. It should always be followed by a prompt neck cutting procedure where all the major blood vessels in the neck are severed. Irrespective of the waveform or frequency of the currents employed, constant current stunners should be installed under commercial conditions to ensure that the minimum currents are delivered to individual birds in waterbath stunners. Head only electrical stunning of poultry is being investigated in detail and there is scope for commercial development. Important features include (a) a constant current capable of delivering a preset current, (b) a bird restraining conveyor and head presentation devices enabling the stunning tongs to be accurately placed, (c) more effective electrical stunning tongs in terms of delivering necessary currents while using low voltages, and (d) induction of cardiac arrest immediately after stunning to eliminate wing flapping. Stunning/killing of poultry still in their transport containers using gas mixtures would appear to be the best future option as far as bird welfare is concerned. However, birds can also be stunned/killed on a conveyor using gas mixtures, thereby eliminating the stress associated with the shackling of live birds before electrical stunning. Under the conveyor system birds should be presented to the gas mixtures in a single layer. Within gas mixtures a minimum of 90% argon in air would appear to be the first choice. A mixture of 30% carbon dioxide and 60% argon in air is better than using a high concentration of carbon dioxide in air, and is therefore considered to be the second choice. A two stage system that involves firstly stunning broilers with a low concentration of carbon dioxide and then killing them with a high concentration of carbon dioxide can be used by those who wish to use this gas for economic reasons. The two stages should be distinctly separated so that the birds are stunned well before exposure to a high concentration of carbon dioxide in air. In comparison with carbon dioxide alone, a mixture of 30% oxygen and 40% carbon dioxide in air prolongs the induction of anaesthesia and the exposure time required to kill the birds. The addition of oxygen to carbon dioxide may therefore not have any benefit to bird welfare or the processors. Mechanical stunning of poultry using penetrating captive bolts or non-penetrating mushroom headed bolts has been developed. However, stunning with these devices results in very severe wing flapping and further research is necessary to find ways of alleviating this problem.

Gas chromatographic measurement of nitrous oxide and carbon dioxide in air using electron capture detection

The concentration of oxygen delivered by a Bird Mark 7 respirator with the air mixture control adjusted to full air dilution was evaluated under clinical circumstances. A mixture of carbon dioxide in air was substituted for oxygen to drive the respirator because the concentration of carbon dioxide in the inspired air could be measured by an analyzer with a short response time. One hundred and three single inspirations of 7 participants were analyzed for inspired concentration of carbon dioxide tracer gas; for peak and mean flows; and for pressure, volume, and cycling time. The concentration of delivered gas was found to be directly proportional to the pressure (P) and inversely related to the mean flow () with the following relationship: inspired concentration = 58.2757 − 0.4567 + 0. 520 P. The concentration of inspired driving gas varied from 31 per cent to 76 per cent. This is less than the inspired concentration predicted from lung—thorax analogs, probably indicating that performance of respirators nee...

Mixtures of carbon dioxide and oxygen are commonly used in the treatment of central retinal artery obstruction to improve retinal oxygenation. While oxygen alone causes retinal vasoconstriction, it is thought that the carbon dioxide balances this effect, even causing a net vasodilatation. To test this hypothesis, normal, healthy volunteers were given 100% oxygen, a mixture of 95% oxygen and 5% carbon dioxide, and a mixture of 5% carbon dioxide in air to breathe. The caliber of large, fluorescein-filled retinal arteries and veins was then measured using computer processing of digitized television images. The marked decrease in arterial and venous caliber caused by 100% oxygen was not reversed by the subsequent addition of 5% carbon dioxide. Moreover, 5% carbon dioxide in air did not cause substantial vasodilatation of the retinal vasculature. The efficacy of adding 5% carbon dioxide to oxygen to treat retinal vascular obstructive diseases is questioned.

Ventilator-induced Lung Injury

According to United Nations Intergovernmental Panel on Climate Change, aviation accounts for 2% of the total global greenhouse gas emissions, with international aviation accounting for 1.3% and by 2050, aviation will account for 3% of total global greenhouse gas emissions. Over the next two decades passenger traffic and air cargo is expected to increase at up to 6% per annum. International flights generate both visible (e.g. con trails) and invisible (e.g. carbon dioxide, nitrogen oxide) emissions across many countries and legal jurisdictions. International emissions were excluded from the Kyoto Protocol and article 2.2 directed The Parties in Annex I of the Protocol to work through United Nations International Civil Aviation Organisation in limiting and reducing greenhouse gas emissions. In this thesis the focus is on carbon dioxide emissions since it is the largest greenhouse gas component in aviation emissions. Members of International Civil Aviation Organisation have adopted global aspirational goals for international aviation of limiting carbon emissions growth to neutral from 2020, including a yearly 2% fuel efficiency improvement. Members agreed to reduce emissions through non-market based measures such as improvements in airline operations, acquiring and updating to new technology, refuelling with sustainable fuel and implementing a global Market Based Measure scheme. At the 39th International Civil Aviation Organisation Assembly, a global carbon offsetting and reduction scheme for international aviation was presented that will be implemented from 2021. This thesis seeks to determine what combination of policies can be used to manage and reduce emissions from Australian international aviation. This thesis commences by estimating the total amount of carbon dioxide and carbon dioxide efficiency of airlines that were serving the Australian international market in 2012. Carbon dioxide efficiency is defined as the amount of carbon dioxide generated for each kilogram of payload flown over a kilometre where payload is the combined weight of passengers, luggage and freight. Qantas, Emirates and Singapore airlines were the top three emitters and AirAsia X and Cathay Pacific achieved the same carbon efficiency of 0.60 grams of carbon dioxide for each kilogram of payload flown over a kilometre and were the two most carbon efficient airlines. AirAsia X and Cathay Pacific utilised the same aircraft type but AirAsia X carried a higher number of passengers in their aircraft that is configured with more seats whereas Cathay Pacific configured the same aircraft with fewer seats but carried a higher amount of freight since Hong Kong is one the busiest airports for freight traffic. Emirates airline had the most carbon dioxide efficient long haul flights but was also the least carbon dioxide efficient on short flights to New Zealand due to low passenger numbers. Qantas and United flew some of the oldest and least efficient aircraft on long haul and this is reflected in their poor carbon dioxide efficiency and higher emissions. The thesis then estimates the growth in emissions over the next 20 years and estimates the likely reductions in emissions growth assuming airlines adopt planned or soon to be implemented abatement options (such as changing their operations, retrofitting their existing fleet or purchasing new aircraft). Marginal abatement cost curves are presented wherein new aircraft acquisitions were financed at 2% to 6% per annum and repaid over 12 and 15 years. Analysis reveals that implementing all the abatement options with negative or zero marginal abatement cost where new aircraft are financed at 6% per annum repaid over 12 years will result in 17.1Mt and 33.6Mt of carbon dioxide emissions but if interest rate was reduced to 2% per annum, emissions are likely to be reduced to 16.9Mt and 31.7Mt in 2020 and 2033 respectively. Increasing the load factor on each flight by 10% and combining flights together would further reduce carbon dioxide emissions to 15.4Mt and 28.8Mt in 2020 and 2033 respectively. The results presented in this thesis have a number of implications for policy makers. Due to Australia’s geographical isolation Australia has some of the longest international flights and airlines serving these routes have widely varying carbon dioxide efficiencies. Providing low cost finance at favourable terms will encourage airlines to upgrade to newer more fuel saving aircraft. Defining the carbon dioxide efficiency metric as the amount of carbon dioxide emitted for transporting the combine weight of passenger, luggage and freight adjusted for flight distance, gives a fairer assessment of an airline’s fuel/ carbon dioxide efficiency regardless of the airline’s business model. Setting a performance standard-based carbon dioxide efficiency metric allows airlines to pick and choose the appropriate means of meeting their commitments. Finally, incorporating target carbon dioxide efficiency into the carbon offsetting and reduction scheme for international aviation provides an additional incentive for airlines not only to reduce emissions but also to improve carbon dioxide efficiency.

The ventilation systems are inadequate, the increase in the amount of carbon dioxide and carbon monoxide in the inner environment can damage human health. In addition, obtaining the level of external environment with excessive ventilation can lead to unnecessary energy consumption. In this study, a system that absorbs air from the environment using carbon dioxide, oxygen and carbon monoxide values in ambient air and controls the operation of the ventilation system that gives fresh air to the environment is designed with fuzzy logic method. The overall purpose of the system is to achieve the ideal ventilation level. Two separate ventilation valves were controlled at the same time with the fuzzy control system designed in the study. The fuzzy control system was created with MATLAB Fuzzy Logic Toolbox and the operating structure of the control system had analyzed.

Changes in the somatosensory evoked potentials and spontaneous electroencephalogram of hens during stunning with a carbon dioxide and argon mixture