Background Extracorporeal membrane oxygenators (ECMO) are currently utilized to mechanically ventilate blood when lung or lung and heart function are impaired, like in cases of acute respiratory distress syndrome (ARDS). ARDS can be caused by severe cases of carbon monoxide (CO) inhalation, which is the leading cause of poison‐related deaths in the United States. ECMOs can be further optimized for severe CO inhalation using visible light to photo‐dissociate CO from hemoglobin (Hb). In previous studies, we combined phototherapy with an ECMO to design a photo‐ECMO device, which significantly increased CO elimination and improved survival in CO‐poisoned animal models using light at 460, 523, and 620 nm wavelengths. Light at 620 nm was the most effective in removing CO. Objective The aim of this study is to analyze the light propagation at 460, 523, and 620 nm wavelengths and the 3D blood flow and heating distribution within the photo‐ECMO device that increased CO elimination in CO‐poisoned animal models. Methods Light propagation, blood flow dynamics, and heat diffusion were modeled using the Monte Carlo method and the laminar Navier‐Stokes and heat diffusion equations, respectively. Results Light at 620 nm propagated through the device blood compartment (4 mm), while light at 460 and 523 nm only penetrated 48% to 50% (~2 mm). The blood flow velocity in the blood compartment varied with regions of high (5 mm/s) and low (1 mm/s) velocity, including stagnant flow. The blood temperatures at the device outlet for 460, 523, and 620 nm wavelengths were approximately 26.7°C, 27.4°C, and 20°C, respectively. However, the maximum temperatures within the blood treatment compartment rose to approximately 71°C, 77°C, and 21°C, respectively. Conclusions As the extent of light propagation correlates with efficiency in photodissociation, the light at 620 nm is the optimal wavelength for removing CO from Hb while maintaining blood temperatures below thermal damage. Measuring the inlet and outlet blood temperatures is not enough to avoid unintentional thermal damage by light irradiation. Computational models can help eliminate risks of excessive heating and improve device development by analyzing design modifications that improve blood flow, like suppressing stagnant flow, further increasing the rate of CO elimination.
The contribution of women in artisanal crayfish harvesting and other related fishery products (seafood) cannot be overemphasized, yet they are being un-noticed economically. This study examined empirically gender differentials in poverty among crayfish harvesting households in Niger Delta Region of Nigeria. A multi-stage and stratified random sampling techniques was employed in selecting a total of 409 (300 males and 109 females) headed crayfish harvesting households. A structured questionnaire and interview schedule survey was used for the study. FGT model was used to analyse gender differences in poverty status of the respondents while Oaxaca–Blinder (O-B) Decomposition Technique was used to decomposed poverty. The result revealed that, female harvesters are more vulnerable to poverty than their male counterparts in the region with their poverty incidence (0.59), poverty depth (0.33) and poverty severity (0.18) being higher than 0.33, 0.32 and 0.17 for males. The aggregate decomposition revealed that gender differentials gap was mostly being accounted for by coefficient component (structural or discrimination effect) than endowment component (characteristics or composition effect) and interaction effect. The detailed decomposition that explained the gender differential gap indicates that marital status, household size and income of crayfish harvesting are the major factors that explained the endowment effect while marital status, labour, income of crayfish harvesting and access to crayfish harvesting net are the factors that explained the structural effect. Additionally, the result of the analysis of poverty coping strategy use index (PCSUI) revealed that spending of saved income (8.16%), children eating first (8.15%), intensifying of the amount of work done on the crayfish fishing to increase output (8.03%), purchasing items on credit (7.98%), diversify off-fishing activities to increase income (7.50%), borrowing money for household upkeep (7.20%), reduction in food consumption (7.20%) among others were the major poverty coping strategies used in the area. The study recommended that gender equality and equity be ensure in the provision, allocation and distribution of productive (harvesting) resources/services. More so, bias and discriminatory laws, norms, belief and traditional restrictions against women should be review and repeal while hidden ones be eliminated among others.
We designed a photo-ECMO device to speed up the rate of carbon monoxide (CO) removal by using visible light to dissociate CO from hemoglobin (Hb). Using computational fluid dynamics, fillets of different radii (5 cm and 10 cm) were applied to the square shape of a photo-ECMO device to reduce stagnant blood flow regions and increase the treated blood volume while being constrained by full light penetration. The blood flow at different flow rates and the thermal load imposed by forty external light sources at 623 nm were modeled using the Navier-Stokes and convection–diffusion equations. The particle residence times were also analyzed to determine the time the blood remained in the device. There was a reduction in the blood flow stagnation as the fillet radii increased. The maximum temperature change for all the geometries was below 4 °C. The optimized device with a fillet radius of 5 cm and a blood priming volume of up to 208 cm3 should decrease the time needed to treat CO poisoning without exceeding the critical threshold for protein denaturation. This technology has the potential to decrease the time for CO removal when treating patients with CO poisoning and pulmonary gas exchange inhibition.
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