Academic literature on the topic 'BBB leakage'
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Journal articles on the topic "BBB leakage"
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Verheggen, Inge C. M., Joost J. A. de Jong, Martin P. J. van Boxtel, Alida A. Postma, Jacobus F. A. Jansen, Frans R. J. Verhey, and Walter H. Backes. "Imaging the role of blood–brain barrier disruption in normal cognitive ageing." GeroScience 42, no. 6 (October 6, 2020): 1751–64. http://dx.doi.org/10.1007/s11357-020-00282-1.
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AbstractTo investigate whether blood–brain barrier (BBB) disruption is a potential mechanism of usual age-related cognitive decline, we conducted dynamic contrast–enhanced (DCE) MRI to measure BBB leakage in a healthy sample, and investigated the association with longitudinal cognitive decline. In a sample of neurologically and cognitively healthy, older individuals, BBB leakage rate in the white and grey matter and hippocampus was measured using DCE MRI with pharmacokinetic modelling. Regression analysis was performed to investigate whether the leakage rate was associated with decline in cognitive performance (memory encoding, memory retrieval, executive functioning and processing speed) over 12 years. White and grey matter BBB leakages were significantly associated with decline in memory retrieval. No significant relations were found between hippocampal BBB leakage and cognitive performance. BBB disruption already being associated with usual cognitive ageing, supports that this neurovascular alteration is a possible explanation for the cognitive decline inherent to the ageing process. More insight into BBB leakage during the normal ageing process could improve estimation and interpretation of leakage rate in pathological conditions. The current results might also stimulate the search for strategies to maintain BBB integrity and help increase the proportion people experiencing successful ageing. Netherlands Trial Register number: NL6358, date of registration: 2017-03-24.
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Arba, Francesco, Richard Leigh, Domenico Inzitari, Steven J. Warach, Marie Luby, and Kennedy R. Lees. "Blood–brain barrier leakage increases with small vessel disease in acute ischemic stroke." Neurology 89, no. 21 (October 25, 2017): 2143–50. http://dx.doi.org/10.1212/wnl.0000000000004677.
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Objective:In patients with acute ischemic stroke, we aimed to investigate the relation between preexisting small vessel disease (SVD) and the amount of blood–brain barrier (BBB) leakage in ischemic and nonischemic area before IV thrombolysis.Methods:We retrospectively accessed anonymous patient-level data from the Stroke Imaging Repository and the Virtual International Stroke Trials Archive resources and included patients treated with IV thrombolysis with pretreatment MRI. We rated SVD features using validated qualitative magnetic resonance (MR) scales. Leakage of BBB was assessed with postprocessing of perfusion-weighted images. We evaluated associations between SVD features (individually and summed in a global SVD score) and BBB leakage using linear regression analysis, adjusting for major clinical confounders.Results:A total of 212 patients, mean age (±SD) 69.5 years (±16.1), 102 (48%) male, had available MR before IV thrombolysis. Evidence of BBB leakage was present in 175 (80%) and 205 (94%) patients in the ischemic and nonischemic area, respectively. Lacunar infarcts (β = 0.17, p = 0.042) were associated with BBB leakage in the ischemic area, and brain atrophy was associated with BBB leakage in both ischemic (β = 0.20, p = 0.026) and nonischemic (β = 0.27, p = 0.001) areas. Increasing SVD grade was independently associated with BBB leakage in both ischemic (β = 0.26, p = 0.007) and nonischemic (β = 0.27, p = 0.003) area.Conclusions:Global SVD burden is associated with increased BBB leakage in both acutely ischemic and nonischemic area. Our results support that SVD score has construct validity, and confirm a relation between SVD and BBB disruption also in patients with acute stroke.
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Hafezi-Moghadam, Ali, Kennard L. Thomas, and Denisa D. Wagner. "ApoE deficiency leads to a progressive age-dependent blood-brain barrier leakage." American Journal of Physiology-Cell Physiology 292, no. 4 (April 2007): C1256—C1262. http://dx.doi.org/10.1152/ajpcell.00563.2005.
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Previously, we reported a defect in the blood-brain barrier (BBB) of apolipoprotein E-deficient (apoE−/−) mice ( 24 ). Here, we investigate BBB permeability in wild-type (WT) and apoE−/− mice as a function of age. Both WT and apoE−/− mice showed significantly increased cortical BBB leakage with age. However, in apoE−/− mice, the leakage increased at a 3.7× higher rate compared with WT mice. Surprisingly, the cerebellum showed significantly more leakage than other brain regions across age, while there was no difference between the two hemispheres. To determine the contribution of tissue- vs. blood-borne apoE to vascular permeability, we generated chimeric mice by bone marrow transplantation and measured their BBB leakage. These experiments suggest that both blood- and tissue-derived apoE are equally important for BBB function. In sum, we find an age-dependent defect in the BBB that is exacerbated in apoE−/− mice. Since vascular defects are found in patients with age-related neurodegenerative diseases, such as Alzheimer's, age-related BBB leakage could underlie these defects and may thus be an important contributor to the cumulative neuronal damage of these diseases.
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Kamintsky, Lyna, Steven D. Beyea, John D. Fisk, Javeria A. Hashmi, Antonina Omisade, Cynthia Calkin, Tim Bardouille, et al. "Blood-brain barrier leakage in systemic lupus erythematosus is associated with gray matter loss and cognitive impairment." Annals of the Rheumatic Diseases 79, no. 12 (October 1, 2020): 1580–87. http://dx.doi.org/10.1136/annrheumdis-2020-218004.
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ObjectivesTo examine the association between blood-brain barrier (BBB) integrity, brain volume and cognitive dysfunction in adult patients with systemic lupus erythematosus (SLE).MethodsA total of 65 ambulatory patients with SLE and 9 healthy controls underwent dynamic contrast-enhanced MRI scanning, for quantitative assessment of BBB permeability. Volumetric data were extracted using the VolBrain pipeline. Global cognitive function was evaluated using a screening battery consisting of tasks falling into five broad cognitive domains, and was compared between patients with normal versus extensive BBB leakage.ResultsPatients with SLE had significantly higher levels of BBB leakage compared with controls (p=0.04). Extensive BBB leakage (affecting over >9% of brain volume) was identified only in patients with SLE (16/65; 24.6%), who also had smaller right and left cerebral grey matter volumes compared with controls (p=0.04). Extensive BBB leakage was associated with lower global cognitive scores (p=0.02), and with the presence of impairment on one or more cognitive tasks (p=0.01).ConclusionOur findings provide evidence for a link between extensive BBB leakage and changes in both brain structure and cognitive function in patients with SLE. Future studies should investigate the mechanisms underlying BBB-mediated cognitive impairment, validate the diagnostic utility of BBB imaging, and determine the potential of targeting the BBB as a therapeutic strategy in patients with SLE.
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Hanly, John G., Alexandra Legge, Lyna Kamintsky, Alon Friedman, Javeria A. Hashmi, Steven D. Beyea, John Fisk, et al. "Role of autoantibodies and blood–brain barrier leakage in cognitive impairment in systemic lupus erythematosus." Lupus Science & Medicine 9, no. 1 (June 2022): e000668. http://dx.doi.org/10.1136/lupus-2022-000668.
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ObjectiveCognitive impairment is common in patients with SLE but the cause is unknown. The current cross-sectional study examined the association between select SLE-related autoantibodies, other serological biomarkers and extensive blood–brain barrier (BBB) leakage in patients with SLE with and without cognitive impairment. In addition, we determined whether the relationship between SLE autoantibodies, other biomarkers and cognitive impairment differed depending on the presence or absence of concurrent extensive BBB leakage.MethodsConsecutive patients with SLE, recruited from a single academic medical centre, underwent formal neuropsychological testing for assessment of cognitive function. On the same day, BBB permeability was determined using dynamic contrast-enhanced MRI scanning. SLE autoantibodies and other serological biomarkers were measured. Regression modelling was used to determine the association between cognitive impairment, extensive BBB leakage and autoantibodies/biomarkers.ResultsThere were 102 patients with SLE; 90% were female and 88% were Caucasian, with a mean±SD age of 48.9±13.8 years. The mean±SD SLE disease duration was 14.8±11.0 years. Impairment in one or more cognitive tests was present in 47 of 101 (47%) patients and included deficits in information processing speed (9%), attention span (21%), new learning (8%), delayed recall (15%) and executive abilities (21%). Extensive BBB leakage was present in 20 of 79 (25%) patients and was associated with cognitive impairment (15 of 20 (75%) vs 24 of 59 (41%); p=0.01) and shorter disease duration (median (IQR): 7 (8–24 years) vs 15 (2–16 years); p=0.02). No serological parameters were associated with extensive BBB leakage and there was no statistically significant association between cognitive impairment and circulating autoantibodies even after adjusting for BBB leakage.ConclusionsExtensive BBB leakage alone was associated with cognitive impairment. These findings suggest that BBB leakage is an important contributor to cognitive impairment, regardless of circulating SLE-related autoantibodies.
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Bender, Benjamin, Kai Herz, Anagha Deshmane, Vivien Richter, Ghazaleh Tabatabai, Jens Schittenhelm, Marco Skardelly, et al. "GLINT: GlucoCEST in neoplastic tumors at 3 T—clinical results of GlucoCEST in gliomas." Magnetic Resonance Materials in Physics, Biology and Medicine 35, no. 1 (December 10, 2021): 77–85. http://dx.doi.org/10.1007/s10334-021-00982-5.
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Abstract Objective Clinical relevance of dynamic glucose enhanced (DGE) chemical exchange saturation transfer (CEST) imaging has mostly been demonstrated at ultra-high field (UHF) due to low effect size. Results of a cohort study at clinical field strength are shown herein. Materials and methods Motion and field inhomogeneity corrected T1ρ‐based DGE (DGE⍴) images were acquired before, during and after a d-glucose injection with 6.3 s temporal resolution to detect accumulation in the brain. Six glioma patients with clear blood–brain barrier (BBB) leakage, two glioma patients with suspected BBB leakage, and three glioma patients without BBB leakage were scanned at 3 T. Results In high-grade gliomas with BBB leakage, d-glucose uptake could be detected in the gadolinium (Gd) enhancing region as well as in the tumor necrosis with a maximum increase of ∆DGE⍴ around 0.25%, whereas unaffected white matter did not show any significant DGE⍴ increase. Glioma patients without Gd enhancement showed no detectable DGE⍴ effect within the tumor. Conclusion First application of DGE⍴ in a patient cohort shows an association between BBB leakage and DGE signal irrespective of the tumor grade. This indicates that glucoCEST corresponds more to the disruptions of BBB with Gd uptake than to the molecular tumor profile or tumor grading.
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Zhang, C. Eleana, Sau May Wong, Harm J. van de Haar, Julie Staals, Jacobus F. A. Jansen, Cécile R. L. P. N. Jeukens, Paul A. M. Hofman, Robert J. van Oostenbrugge, and Walter H. Backes. "Blood–brain barrier leakage is more widespread in patients with cerebral small vessel disease." Neurology 88, no. 5 (December 28, 2016): 426–32. http://dx.doi.org/10.1212/wnl.0000000000003556.
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Objective:As blood–brain barrier (BBB) dysfunction may occur in normal aging but may also play a pivotal role in the pathophysiology of cerebral small vessel disease (cSVD), we used dynamic contrast-enhanced (DCE)–MRI to quantify the rate and the spatial extent of BBB leakage in patients with cSVD and age- and sex-matched controls to discern cSVD-related BBB leakage from aging-related leakage.Methods:We performed structural brain MRI and DCE-MRI in 80 patients with clinically overt cSVD and 40 age- and sex-matched controls. Using the Patlak pharmacokinetic model, we calculated the leakage rate. The mean leakage rate and relative leakage volume were calculated using noise-corrected histogram analysis. Leakage rate and leakage volume were compared between patients with cSVD and controls for the normal-appearing white matter (NAWM), white matter hyperintensities (WMH), cortical gray matter (CGM), and deep gray matter.Results:Multivariable linear regression analyses adjusting for age, sex, and cardiovascular risk factors showed that the leakage volume of the NAWM, WMH, and CGM was significantly larger in patients with cSVD compared with controls. No significant difference was found for leakage rate in any of the tissue regions.Conclusion:We demonstrated a larger tissue volume with subtle BBB leakage in patients with cSVD than in controls. This was shown in the NAWM, WMH, and CGM, supporting the generalized nature of cSVD.
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Cho, Eunice E., Jelena Drazic, Milan Ganguly, Bojana Stefanovic, and Kullervo Hynynen. "Two-Photon Fluorescence Microscopy Study of Cerebrovascular Dynamics in Ultrasound-Induced Blood—Brain Barrier Opening." Journal of Cerebral Blood Flow & Metabolism 31, no. 9 (April 20, 2011): 1852–62. http://dx.doi.org/10.1038/jcbfm.2011.59.
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Blood-brain barrier (BBB) disruption can be achieved with ultrasound (US) and circulating microbubble (MB) contrast agent. Using dorsal US sonication and Definity, an MB contrast agent, responses of the cortical cerebral vasculature to BBB opening were observed with varying acoustic peak negative pressure (0.071 to 0.25 MPa) under two-photon microscope. Wistar rats with a craniotomy were sonicated with a single piezoelectric transducer following the intravenous injection of Texas Red for visualization of vasculature and leakage from BBB opening. Based on time-dependent intensity change in the extravascular area, the leakage was classified into three types: fast, sustained, and slow. Fast leakage was characterized by a rapid increase to peak intensity during sonication, but a decrease afterwards, occurring at all pressures and vessels sizes analyzed in our study. Sustained leakage was indicated by a similar, immediate increase to peak intensity but one that remained elevated for the duration of imaging, occurring at low-to-intermediate pressures. Slow leakage began 5 to 15 minutes after sonication, dominating at low pressures, and was more prevalent among smaller vessels than fast and sustained leakage. Our study showed the possibility of controlling leakage type and vessel size in US-induced BBB opening through varying acoustic pressure.
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Li, Xiaolong, Yan Cai, Zuo Zhang, and Jiyin Zhou. "Glial and Vascular Cell Regulation of the Blood-Brain Barrier in Diabetes." Diabetes & Metabolism Journal 46, no. 2 (March 31, 2022): 222–38. http://dx.doi.org/10.4093/dmj.2021.0146.
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As a structural barrier, the blood-brain barrier (BBB) is located at the interface between the brain parenchyma and blood, and modulates communication between the brain and blood microenvironment to maintain homeostasis. The BBB is composed of endothelial cells, basement membrane, pericytes, and astrocytic end feet. BBB impairment is a distinguishing and pathogenic factor in diabetic encephalopathy. Diabetes causes leakage of the BBB through downregulation of tight junction proteins, resulting in impaired functioning of endothelial cells, pericytes, astrocytes, microglia, nerve/glial antigen 2-glia, and oligodendrocytes. However, the temporal regulation, mechanisms of molecular and signaling pathways, and consequences of BBB impairment in diabetes are not well understood. Consequently, the efficacy of therapies diabetes targeting BBB leakage still lags behind the requirements. This review summarizes the recent research on the effects of diabetes on BBB composition and the potential roles of glial and vascular cells as therapeutic targets for BBB disruption in diabetic encephalopathy.
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Kerkhofs, Danielle, Sau May Wong, Eleana Zhang, Julie Staals, Jacobus F. A. Jansen, Robert J. van Oostenbrugge, and Walter H. Backes. "Baseline Blood-Brain Barrier Leakage and Longitudinal Microstructural Tissue Damage in the Periphery of White Matter Hyperintensities." Neurology 96, no. 17 (March 24, 2021): e2192-e2200. http://dx.doi.org/10.1212/wnl.0000000000011783.
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ObjectiveTo investigate the 2-year change in parenchymal diffusivity, a quantitative marker of microstructural tissue condition, and the relationship with baseline blood-brain barrier (BBB) permeability, in tissue at risk, i.e., the perilesional zone surrounding white matter hyperintensities (WMH) in patients with cerebral small vessel disease (cSVD).MethodsPatients with sporadic cSVD (lacunar stroke or mild vascular cognitive impairment) underwent 3T MRI at baseline, including dynamic contrast-enhanced MRI to quantify BBB permeability (i.e., leakage volume and rate) and intravoxel incoherent motion imaging (IVIM), a diffusion technique that provides parenchymal diffusivity D. After 2 years, IVIM was repeated. We assessed the relation between BBB leakage measures at baseline and change in parenchymal diffusivity (∆D) over 2 years in the perilesional zones (divided in 2-mm contours) surrounding WMH.ResultsWe analyzed 43 patients (age 68 ± 12 years, 58% male). In the perilesional zones, ∆D increased 0.10% (confidence interval [CI] 0.07–0.013%) (p < 0.01) per 2 mm closer to the WMH. Furthermore, ∆D over 2 years showed a positive correlation with both baseline BBB leakage volume (r = 0.29 [CI 0.06–0.52], p = 0.013) and leakage rate (r = 0.24 [CI 0.02–0.47], p = 0.034).ConclusionBBB leakage at baseline is related to the 2-year change in parenchymal diffusivity in the perilesional zone of WMH. These results support the hypothesis that BBB impairment might play an early role in subsequent microstructural white matter degeneration as part of the pathophysiology of cSVD.
Dissertations / Theses on the topic "BBB leakage"
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Gomez, Adrian. "Identification and evaluation of internal leakages of a BFB Boiler integrated within a pulp and paper mill." Thesis, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-27110.
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Alternative fuels like biomass have become really popular in the last decades as a substitute to fossil fuels. One of the most used technologies in Sweden for the obtention of the energy from the biomass is its direct combustion in a boiler. Bomhus Energi is a company with the purpose of creating steam and district heating for Billerudkorsnäs pulp and paper mill in Gävle and district heating for the city by operating a biomass BFB boiler. Despite being a quite new boiler, there are many sources of errors, losses and unnecessary costs. Between huge number of different losses that can happen in this kind of industrial boilers, the concern about internal leakages is not usually popular among plant designers and operators. This often leads to forget about them or not giving the importance that they could have.This study consists on, firstly, an analysis of different boiler equipment that have potential possibilities of internal leakages by mass and energy balances and by the tracking of possible mass losses. The second point of this thesis is to evaluate the cost of internal leakages that could have happen before, in order to be aware of how important they are. Additionally, measures are proposed in order to avoid or reduce the duration of the internal leakages, where the most common problem is the ignorance of their existence. This study focuses partially on the valve condition and maintenance. It is highly important to carry out valve maintenance procedures at least once per year during the general stop of the plant. Checking and verifying valve perfect conditions, can avoid a waste of a huge quantity of money just by replacing some internal elements that are possibly damaged due to the extreme working conditions. This small damages in valve can lead to a non-proper water tightening, which will be increasing its leakage over time. In the present paper, possible internal leakages through the valves belonging to the feedwater, steam drum, preheater and pressure vessel in general have been the principal aim. The key of this study was to take into account that biggest part of the draining system and valves that are supposed to be closed end in the Bottom blowdown tank. By then a deep study was done regarding this tank. The results show that there is a clear relationship between mass that is getting loss from feedwater tank and pressure vessel and the necessary cooling flow in the bottom blowdown tank. This means that if the cooling flow increases at the same rate as a possible leakage in mass and energy balance, there is an internal leakage somewhere in the system. The author proposes add an alarm to the DCS system in order to alert the plant operations of possible internal leakages. On the other hand, this paper also recommends to carry out a general valve maintenance per year and check which of them could be leaking, a general stop is the perfect time for carrying it out.In conclusion, the study finds that internal leakages can be even automatically detected if the system is provided with the necessary tools for it. The study concludes that internal leakages are not impossible to detect and their cost is non-negligible: the latest two internal leakages in the boiler, happened in the last two years, were from the feedwater draining system and from the steam drum heating loop with a total cost of 200,000 SEK (4240 SEK/day during 47 days) and 263,000 SEK (2120 SEK/day during 124 days) respectively. Additionally, days after the study, the plant general stop was carried out, finding that 12 valves were leaking due to internal damage. The cost of repairing the broken or damaged elements were almost negligible compared with the expected savings estimated in 2 Million SEK per year.
Book chapters on the topic "BBB leakage"
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Badyal, Priya, Jaspreet Kaur, and Anurag Kuhad. "Role of 5-HT in Cerebral Edema after Traumatic Brain Injury." In Serotonin and the CNS - New Developments in Pharmacology and Therapeutics [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.96460.
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The pathogenesis of edema after traumatic brain injury is complex including the destruction of micro-vessels and alterations in microcirculation around the primary injury and leakage of plasma constituents into the tissue, due to permeability changes of the vessel walls. Many functional molecules like histamine, serotonin, arachidonic acid, prostaglandins and thromboxane have been shown to induce blood–brain barrier (BBB) disruption or cell swelling. It is believed that released 5-HT binds to 5-HT2 receptors stimulating cAMP and prostaglandins in vessels that cause more vesicular transport in endothelial cells leading to serum component’s extravasation. The additional amount of serotonin into the tissue due to injury maintains the state of increased vascular permeability that ultimately causes edema. Serotonin is clearly involved in early cytotoxic edema after TBI. Reduction of serotonin in the nervous tissue reduces swelling and the milder cell changes in the brain or spinal cord of traumatized rats. Inhibition of serotonin synthesis before closed head injury (CHI) in rat models or administration of serotonin antiserum after injury attenuates BBB disruption and brain edema volume swelling, and brain pathology. Maintaining low serotonin levels immediately after injury may show neuroprotection and combat various secondary outcomes that occur after traumatic brain injury.
Conference papers on the topic "BBB leakage"
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Chiu, Wei-Yu, Fan-Hsiu Huang, Yen-Shian Wu, Don-Ming Lin, Shu-Han Chen, Jin-Wei Shi, Jen-Inn Chyi, and Yi-Jen Chan. "Reduced Mesa-Sidewall Leakage Current in InGaAs/InP MSM Photodetector by BCB Sidewall Process." In 2004 International Conference on Solid State Devices and Materials. The Japan Society of Applied Physics, 2004. http://dx.doi.org/10.7567/ssdm.2004.h-10-4.
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Kim, Sang U., Taiheui Cho, and Paul Ho. "Thermal and Bias-Temperature Stress Induced Leakage Current Failure of Cu/BCB Single Damascene Integration." In 1998 International Conference on Solid State Devices and Materials. The Japan Society of Applied Physics, 1998. http://dx.doi.org/10.7567/ssdm.1998.a-6-6.
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Zhang, Chaowei, Xuezhi Dong, Xiyang Liu, and Hualiang Zhang. "Numerical Investigations on Slip Characteristics and Slip Onset Position in High-Loaded Backswept Centrifugal Impellers." In GPPS Xi'an21. GPPS, 2022. http://dx.doi.org/10.33737/gpps21-tc-87.
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This paper mainly investigates the effect of mass flow, blade turning and tip clearance size on the slip characteristics in the high-loaded backswept centrifugal impeller by numerical simulation. The numerical results show that the slip onset position mainly depends on the blade loading and the intensity of tip leakage flow. The mass-averaged slip onset position moves upstream but changes little with increased mass flow. The mass-averaged slip onset position is very close to the position of the peak value in the B2B blade loadings at the design condition. With increased exit blade angle, the mass-averaged slip onset position moves downstream and the mass-averaged slip factor increases. With increased tip clearance size, the mass-averaged slip onset position moves downstream first and then upstream. This study can supply some guidance to develop the slip onset position prediction model for high-loaded backswept centrifugal impellers.
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Hsieh, C. C., Yousef Alyousef, and S. C. Yao. "Development of a Silicon-Based Passive Gas-Liquid Separation System for Microscale Direct Methanol Fuel Cells." In ASME 4th International Conference on Nanochannels, Microchannels, and Minichannels. ASMEDC, 2006. http://dx.doi.org/10.1115/icnmm2006-96084.
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The design, fabrication, and performance characterization of a passive gas-liquid separation system is presented in this paper. The gas-liquid separation system is silicon-based and its fabrication is compatible with the existing CMU design of the microscale direct methanol fuel cell (DMFC). Both gas and liquid separators consist of staggered arrays of etched-through holes fabricated by deep reactive ion etching (DRIE). The gas separator is coated with a thin layer of hydrophobic polymer to substantiate the gas-liquid separation. To visually characterize the system performance, the gas-liquid separation system is made on a single wafer with a glass plate bonded on the top to form a separation chamber with a narrow gap in between. Benzocyclobutene (BCB) is applied for the low-temperature bonding. The maximum pressure for the liquid leakage of the gas separators is experimentally determined and compared with the values predicted theoretically. Several successful gas-liquid separations are observed at liquid pressures between 14.2 and 22.7 cmH2O, liquid flow rates between 0.705 and 1.786 cc/min, and CO2 flow rates between 0.15160 to 0.20435 cc/min.
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Hsieh, C. C., S. C. Yao, and Yousef Alyousef. "Development of a Silicon-Based Passive Gas-Liquid Separation System for Microscale Direct Methanol Fuel Cells." In ASME 2003 International Mechanical Engineering Congress and Exposition. ASMEDC, 2003. http://dx.doi.org/10.1115/imece2003-42135.
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The design, fabrication, and performance characterization of a passive gas-liquid separation system is presented in this paper. The gas-liquid separation system is silicon-based and its fabrication is compatible with the existing CMU design of the microscale direct methanol fuel cell (DMFC). Both gas and liquid separators consist of staggered arrays of etched-through holes fabricated by deep reactive ion etching (DRIE). The gas separator is coated with a thin layer of hydrophobic polymer to substantiate the gas-liquid separation. To visually characterize the system performance, the gas-liquid separation system is made on a single wafer with a glass plate bonded on the top to form a separation chamber with a narrow gap in between. Benzocyclobutene (BCB) is applied for the low-temperature bonding. The maximum pressure for the liquid leakage of the gas separators is experimentally determined and compared with the values predicted theoretically. Several successful gas-liquid separations are observed at liquid pressures between 14.2 and 22.7 cmH2O, liquid flow rates between 0.705 and 1.786 cc/min, and CO2 flow rates between 0.15160 to 0.20435 cc/min.