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Alnagar AM, Hakeem AR, Daradka K, Kyrana E, Methga M, Palaniswamy K, Rajwal S, Mulla J, O'meara M, Upasani V, Vijayanand D, Prasad R, Attia MS. Long-term outcomes of pediatric liver transplantation in acute liver failure vs end-stage chronic liver disease: A retrospective observational study. World J Transplant 2023; 13:96-106. [PMID: 36968135 PMCID: PMC10037232 DOI: 10.5500/wjt.v13.i3.96] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 12/22/2022] [Accepted: 03/06/2023] [Indexed: 03/16/2023] Open
Abstract
BACKGROUND Children with acute liver failure (ALF) who meet the criteria are eligible for super-urgent transplantation, whereas children with end-stage chronic liver disease (ESCLD) are usually transplanted electively. Pediatric liver transplantation (PLT) in ALF and ESCLD settings has been well described in the literature, but there are no studies comparing the outcomes in these two groups.
AIM To determine if there is a difference in post-operative complications and survival outcomes between ALF and ESCLD in PLT.
METHODS This was a retrospective observational study of all primary PLTs performed at a single center between 2000 and 2019. ALF and ESCLD groups were compared for pretransplant recipient, donor and operative parameters, and post-operative outcomes including graft and patient survival.
RESULTS Over a 20-year study period, 232 primary PLTs were performed at our center; 195 were transplanted for ESCLD and 37 were transplanted for ALF. The ALF recipients were significantly older (median 8 years vs 5.4 years; P = 0.031) and heavier (31 kg vs 21 kg; P = 0.011). Living donor grafts were used more in the ESCLD group (34 vs 0; P = 0.006). There was no difference between the two groups concerning vascular complications and rejection, but there were more bile leaks in the ESCLD group. Post-transplant patient survival was significantly higher in the ESCLD group: 1-, 5-, and 10-year survival rates were 97.9%, 93.9%, and 89.4%, respectively, compared to 78.3%, 78.3%, and 78.3% in the ALF group (P = 0.007). However, there was no difference in 1-, 5-, and 10-year graft survival between the ESCLD and ALF groups (90.7%, 82.9%, 77.3% vs 75.6%, 72.4%, and 66.9%; P = 0.119).
CONCLUSION Patient survival is inferior in ALF compared to ESCLD recipients; the main reason is death in the 1st year post-PLT in ALF group. Once the ALF children overcome the 1st year after transplant, their survival stabilizes, and they have good long-term outcomes.
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Affiliation(s)
- Amr M Alnagar
- Department of General Surgery, Faculty of Medicine, Alexandria University, Alexandria 21615, Egypt
- Liver and Transplant Surgery, The Leeds Teaching Hospitals, NHS Foundation Trust, Leeds LS9 7TF, United Kingdom
| | - Abdul R Hakeem
- Liver and Transplant Surgery, The Leeds Teaching Hospitals, NHS Foundation Trust, Leeds LS9 7TF, United Kingdom
| | - Khaled Daradka
- Liver and Transplant Surgery, The Leeds Teaching Hospitals, NHS Foundation Trust, Leeds LS9 7TF, United Kingdom
| | - Eirini Kyrana
- Liver and Transplant Surgery, The Leeds Teaching Hospitals, NHS Foundation Trust, Leeds LS9 7TF, United Kingdom
| | - Marumbo Methga
- Liver and Transplant Surgery, The Leeds Teaching Hospitals, NHS Foundation Trust, Leeds LS9 7TF, United Kingdom
| | - Karthikeyan Palaniswamy
- Liver and Transplant Surgery, The Leeds Teaching Hospitals, NHS Foundation Trust, Leeds LS9 7TF, United Kingdom
| | - Sanjay Rajwal
- Liver and Transplant Surgery, The Leeds Teaching Hospitals, NHS Foundation Trust, Leeds LS9 7TF, United Kingdom
| | - Jamila Mulla
- Liver and Transplant Surgery, The Leeds Teaching Hospitals, NHS Foundation Trust, Leeds LS9 7TF, United Kingdom
| | - Moira O'meara
- Liver and Transplant Surgery, The Leeds Teaching Hospitals, NHS Foundation Trust, Leeds LS9 7TF, United Kingdom
| | - Vivek Upasani
- Liver and Transplant Surgery, The Leeds Teaching Hospitals, NHS Foundation Trust, Leeds LS9 7TF, United Kingdom
| | - Dhakshinamoorthy Vijayanand
- Liver and Transplant Surgery, The Leeds Teaching Hospitals, NHS Foundation Trust, Leeds LS9 7TF, United Kingdom
| | - Raj Prasad
- Liver and Transplant Surgery, The Leeds Teaching Hospitals, NHS Foundation Trust, Leeds LS9 7TF, United Kingdom
| | - Magdy S Attia
- Liver and Transplant Surgery, The Leeds Teaching Hospitals, NHS Foundation Trust, Leeds LS9 7TF, United Kingdom
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Chandran M, Palaniswamy K, Karthik Babu NB, Das O. A study of the influence of current ramp rate on the performance of polymer electrolyte membrane fuel cell. Sci Rep 2022; 12:21888. [PMID: 36535964 PMCID: PMC9763490 DOI: 10.1038/s41598-022-25037-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Accepted: 11/23/2022] [Indexed: 12/23/2022] Open
Abstract
Durability and reliability are the key factors that prevent fuel cells from successful implementation in automotive sector. Dynamic load change is a common and frequent condition that the fuel cell has to undergo in automotive applications. Fuel cells are more sensitive to changes in load conditions and degrade based on load variation representing idling, rated power, and high power operating conditions. To examine the influence of dynamic load step on the fuel cell performance, two similar cells of active 25 cm2 was tested under two different load step for the same dynamic load cycle. The main difference in dynamic load cycle 2 was the ramp rate which was fixed as 0.1, 0.3, and 0.25 A/cm2/s for 0.2, 0.6, and 1.0 A/cm2 respectively. To investigate the degradative effects, polarization curves, electrochemical impedance spectroscopy, and field emission scanning electron microscopy were used. The results indicated that the degradation rate increased in both dynamic load cycles but however the impact of load change was comparatively minimal in dynamic load cycle 2. The total degradation in performance was 20.67% and 10.72% in dynamic load cycles 1 and 2 respectively. Fuel cell performance degraded in a manner that was consistent with the electrochemical impedance spectroscopy and cross-sectional analysis of field emission scanning electron microscopy. The results prove that the degradation rate is dependent on the load step and the number of load cycles. Severe catalyst degradation and delamination were observed in fuel cells operated under dynamic load cycle 1.
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Affiliation(s)
- Mathan Chandran
- grid.252262.30000 0001 0613 6919Fuel Cell Energy System Lab, Department of Automobile Engineering, PSG College of Technology, Coimbatore, Tamilnadu India
| | - Karthikeyan Palaniswamy
- grid.252262.30000 0001 0613 6919Department of Automobile Engineering, PSG College of Technology, Coimbatore, Tamilnadu India
| | - N. B. Karthik Babu
- grid.464657.20000 0004 0478 3209Department of Mechanical Engineering, Assam Energy Institute, Centre of Rajiv Gandhi Institute of Petroleum Technology, Sivasagar, Assam 785697 India
| | - Oisik Das
- grid.6926.b0000 0001 1014 8699Structural and Fire Engineering Division, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, 97187 Luleå, Sweden
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Schmidt J, Pisarczyk K, Leff R, Palaniswamy K, Park E, Long L. AB1279 POOR QUALITY OF LIFE AND REDUCED WORK PRODUCTIVITY IN EUROPEAN PATIENTS WITH DERMATOMYOSITIS AND POLYMYOSITIS: FINDINGS FROM A SYSTEMATIC LITERATURE REVIEW. Ann Rheum Dis 2022. [DOI: 10.1136/annrheumdis-2022-eular.1056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BackgroundDermatomyositis (DM) and polymyositis (PM) are rare heterogenous systemic autoimmune disorders of the skin, muscles, and other organs with few effective treatment options available. They are described as devastating diseases but the full impact on patients’ lives in Europe is not well understood.ObjectivesTo systematically review and summarize evidence on humanistic burden of disease in patients with DM and PM in Europe to better understand patient-relevant aspects of disease and key domains of life impacted by DM and PM in the European setting.MethodsA systematic literature review (SLR) was conducted in MEDLINE and Embase databases to identify studies in children and adults with DM and PM, published in the English language between Jan 1, 2011, and Apr 28, 2021. Only primary studies enrolling 10 or more patients were included, irrespective of country or region. Each eligible article was independently reviewed by two reviewers. The title and study abstracts were reviewed to assess eligibility for full-text review. The topics of interest were clinical, humanistic, and economic burden of disease, as well as current management and unmet needs in DM and PM. Information on geographic scope was extracted from the papers of included studies. The current abstract summarizes SLR results on humanistic burden of DM and PM in European patients.ResultsA total of 2,967 non-duplicated publications were retrieved from medical databases and analyzed against pre-defined study selection criteria. There were 2,574 records excluded at title and abstract screening. Remaining 393 records were analyzed in the full text with 208 papers considered relevant. Additional 21 papers were identified from searching reference list of relevant studies and conference proceedings. In total, 222 studies described in 229 publications were included in data abstraction. Among 43 studies conducted across 14 European countries, 12 studies evaluated health-related quality of life (HRQoL) and work productivity in patients with DM and PM. In 6 studies, patients received standard of care therapy. Six studies enrolled adults with DM and PM and 6 were conducted in patients with juvenile onset of DM. There were 6 cross-sectional analyses, 4 longitudinal cohort studies, 2 case-control studies, with sample size ranging from 11 to 246 patients. Adults with DM and PM had significantly worse HRQoL across multiple domains of 36-Item Short Form Survey (SF-36) compared to controls from general population, with a strong negative impact of muscle weakness on physical functioning. Patients reported high difficulties in performing leisure time activities, moving around and work as indicated by median scores of 4-5 points in a 7-point Myositis Activity Profile (MAP). Reduced grip force in DM and PM adults was significantly associated with worse performance in domestic activities in the MAP assessment (p<0.05). In women with DM and PM, poor grip force additionally impacted vitality and mental health as measured by SF-36 (p<0.05). There were no associations between grip force and any SF-36 domain in men. Approximately 60% of adult patients rated their ability to work as “poor” or “less good” according to the Work Ability Index, 68% of patients had more than one week of sick leave in the past year, and 20.8% of them were permanently not able to work for at least 2 years. Children and adolescents with DM had impaired physical and psychosocial functioning compared to healthy norms with 40% of individuals showing increased emotional distress requiring in-depth psychological assessment.ConclusionEuropean patients with DM and PM experience a muscle weakness that has a detrimental impact on HRQoL, daily activities and ability to work. Similar disease impact on HRQoL was reported in patients in North America. These findings suggest a need for a novel therapy that will restore physical functioning in patients with DM and PM.Disclosure of InterestsJens Schmidt Speakers bureau: Euroimmun, CSL Behring, Consultant of: Alnylam, Argenx, Biotest, CSL Behring, Kezar Life Sciences, LFB, Novartis, Octapharma, UCB, Grant/research support from: CSL Behring, Novartis, Konrad Pisarczyk Consultant of: Kezar Life Sciences, Richard Leff Shareholder of: Kezar Life Sciences, Consultant of: Kezar Life Sciences, Kiruthi Palaniswamy Shareholder of: Kezar Life Sciences, Employee of: Kezar Life Sciences, Eunmi Park Shareholder of: Kezar Life Sciences, Employee of: Kezar Life Sciences, Li Long Shareholder of: Kezar Life Sciences, Employee of: Kezar Life Sciences
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Vencovský J, Pisarczyk K, Leff R, Park E, Palaniswamy K, Long L. AB1277 POOR LONG-TERM OUTCOMES AND SUBSTANTIAL BURDEN OF COMORBIDITIES IN EUROPEAN PATIENTS WITH DERMATOMYOSITIS/POLYMYOSITIS: RESULTS FROM A SYSTEMATIC LITERATURE REVIEW. Ann Rheum Dis 2022. [DOI: 10.1136/annrheumdis-2022-eular.756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BackgroundDermatomyositis (DM) and polymyositis (PM) are rare heterogenous systemic autoimmune disorders of the skin, muscles and other organs that may have a devastating impact on patients’ lives. Despite various therapies used in clinical practice, a notable proportion of patients seem not to achieve sustainable remission. There is a need to better understand long-term outcomes and comorbidities in patients with DM/PM in Europe.ObjectivesTo systematically review and summarize evidence on clinical burden of disease in patients with DM/PM in Europe.MethodsA systematic literature review (SLR) was conducted in MEDLINE and Embase databases to identify studies in children and adults with DM/PM, published in the English language between 2011 and 2021. Primary studies enrolling 10 or more patients were included, irrespective of country or region. Each eligible article was independently reviewed by two reviewers. The title and study abstracts were reviewed to assess eligibility for full-text review. The current abstract summarizes SLR results on the long-term outcomes and comorbidities in patients with DM/PM in Europe.ResultsA total of 2,967 non-duplicated publications were retrieved from medical databases and analyzed against pre-defined study selection criteria. There were 2,574 records excluded at title and abstract screening. Remaining 393 records were analyzed in the full text with 208 papers considered relevant. Additional 21 papers were identified from searching reference list of relevant studies and conference proceedings. In total, 222 studies (229 publications) were included in data abstraction. Among 43 studies conducted across 14 European countries, 23 studies evaluated long-term outcomes of disease and burden of comorbidities. There were 14 longitudinal cohort studies, 7 cross-sectional analyses and 2 case-control studies. Only 29-44% of DM/PM adults achieved remission. Between 38% and 62% of adults with DM/PM required at least 3 different medications, suggesting inadequate response to initial and subsequent regimens. During a mean follow-up of 13.9 years, 69% patients with JDM had polycyclic or chronic disease characterized by periods of remission and recurrence or by permanently active disease for more than 2 years after diagnosis. A notable proportion of children (60.4%) showed evidence of damage in at least one body organ and 13-20% of patients had complications such as calcinosis, lipodystrophy, or muscle atrophy. Adults with DM/PM often suffered from interstitial lung disease (16-66%), serious infections leading to hospitalization or death (21-26.7%), and cardiovascular disorders (CVDs) (19-71%). Compared to age and gender matched controls without DM, patients with DM had 16-times higher risk of venous thromboembolism (HR=16.44, 95% CI: 7.54-35.86). Incidence of coronary heart disease, hemorrhagic stroke, or ischemic stroke during 10-year follow-up was approximately 1.5- to 2-times higher in DM/PM adults relative to general population. Multiple studies reported high rates of any malignancy in DM adults (7.5-33%) and in PM adults (8-11.7%). During approximately 24,000 patient-years of follow-up, adults with DM/PM had more than 4-times higher incidence of lung cancer compared to general population that also was one of the highest incidences among multiple other autoimmune diseases. Long-term prognosis in DM/PM was poor with 20-year survival below 70%. The most common causes of deaths were pulmonary-related, malignancies, and cardiac complications. Mortality due to lung cancer was more than 4-times higher than in general population (standardized mortality ratio=4.17, 95% CI: 3.03-5.60).ConclusionEuropean patients with DM/PM suffer from substantial burden of comorbidities including serious infections, malignancies and CVDs that lead to poor long-term outcomes. A notable proportion of adult and juvenile patients do not achieve sustainable remission or experience relapse indicating high unmet need.Disclosure of InterestsJiří Vencovský Speakers bureau: Abbvie, Biogen, Boehringer, Eli Lilly, Gilead, MSD, Novartis, Pfizer, Roche, Sanofi, UCB, Werfen, Consultant of: Abbvie, Argenx, Boehringer, Eli Lilly, Gilead, Octapharma, Pfizer, UCB, Grant/research support from: Abbvie, Konrad Pisarczyk Consultant of: Kezar Life Sciences, Richard Leff Shareholder of: Kezar Life Sciences, Consultant of: Kezar Life Sciences, Eunmi Park Shareholder of: Kezar Life Sciences, Employee of: Kezar Life Sciences, Kiruthi Palaniswamy Shareholder of: Kezar Life Sciences, Employee of: Kezar Life Sciences, Li Long Shareholder of: Kezar Life Sciences, Employee of: Kezar Life Sciences.
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Alnagar A, Daradka K, Kyrana E, Mtegha M, Palaniswamy K, Rajwal S, Mulla J, O'meara M, Karam M, Shawky A, Hakeem AR, Upasani V, Dhakshinamoorthy V, Prasad R, Attia M. Predictors of patient and graft survival following pediatric liver transplantation: Long-term analysis of more than 300 cases from single centre. Pediatr Transplant 2022; 26:e14139. [PMID: 34545678 DOI: 10.1111/petr.14139] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Revised: 08/04/2021] [Accepted: 08/28/2021] [Indexed: 11/30/2022]
Abstract
BACKGROUND Pediatric liver transplant (PLT) activity has flourished over time although with limited expansion in the graft pool. The study aims to identify pre-transplant factors that predict post-transplant patient and graft survival in the PLT population. METHODS Retrospective review of PLTs at a single tertiary transplant unit from 2000 to 2019. Univariate and multivariate analyses of pre-transplant factors were performed to identify predictors of patient and graft survival. RESULTS Two hundred and seventy-six patients received 320 PLTs. The most common cause of graft loss was hepatic artery thrombosis (n = 13, 29.6%). The most common cause of mortality was sepsis (n = 11, 29.7%). Univariate analysis showed that the following variables had a significant (p < .05) impact on patient survival: recipient age, weight, height, graft type (technical variant graft), transplant category (acute liver failure), the era of transplant, and invasive ventilation. The following variables had a significant (p < .05) impact on graft survival: recipient age, weight, height, transplant category (acute liver failure), and the era of transplant. Multivariate analysis precluded the era of transplant as the only significant factor for patient survival; patients transplanted after 2005 had significantly higher patient survival. No independent factor predicting graft survival was identified. For children transplanted after 2005, the only factor that predicted patient survival was pre-transplant invasive ventilation. CONCLUSIONS Our study suggests that the learning curve and pre-transplant invasive ventilation in the recipient have a significant impact on patient survival. The traditional view of worse outcomes of smaller PLT candidates should be changed.
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Affiliation(s)
- Amr Alnagar
- The Leeds Teaching Hospitals, NHS Foundation Trust, Leeds, UK.,General Surgery Department, Faculty of Medicine, Alexandria University, Alexandria, Egypt
| | - Khaled Daradka
- The Leeds Teaching Hospitals, NHS Foundation Trust, Leeds, UK.,Department of General Surgery, Jordan University Hospital, The University of Jordan- Queen Rania Street, Amman, Jordan
| | - Eirini Kyrana
- The Leeds Teaching Hospitals, NHS Foundation Trust, Leeds, UK
| | - Marumbo Mtegha
- The Leeds Teaching Hospitals, NHS Foundation Trust, Leeds, UK
| | | | - Sanjay Rajwal
- The Leeds Teaching Hospitals, NHS Foundation Trust, Leeds, UK
| | - Jamila Mulla
- The Leeds Teaching Hospitals, NHS Foundation Trust, Leeds, UK
| | - Moira O'meara
- The Leeds Teaching Hospitals, NHS Foundation Trust, Leeds, UK
| | - Mohamed Karam
- General Surgery Department, Faculty of Medicine, Alexandria University, Alexandria, Egypt
| | - Ahmed Shawky
- General Surgery Department, Faculty of Medicine, Alexandria University, Alexandria, Egypt
| | | | - Vivek Upasani
- The Leeds Teaching Hospitals, NHS Foundation Trust, Leeds, UK
| | | | - Raj Prasad
- The Leeds Teaching Hospitals, NHS Foundation Trust, Leeds, UK
| | - Magdy Attia
- The Leeds Teaching Hospitals, NHS Foundation Trust, Leeds, UK
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Marappan M, Palaniswamy K, Velumani T, Chul KB, Velayutham R, Shivakumar P, Sundaram S. Performance Studies of Proton Exchange Membrane Fuel Cells with Different Flow Field Designs - Review. CHEM REC 2021; 21:663-714. [PMID: 33543591 DOI: 10.1002/tcr.202000138] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 12/21/2020] [Accepted: 01/13/2021] [Indexed: 01/10/2023]
Abstract
Proton Exchange Membrane Fuel Cell (PEMFC) is majorly used for power generation without producing any emission. In PEMFC, the water generated in the cathode heavily affects the performance of fuel cell which needs better water management. The flow channel designs, dimensions, shape and size of the rib/channel, effective area of the flow channel and material properties are considered for better water management and performance enhancement of the PEMFC in addition to the inlet reactant's mass flow rate, flow directions, relative humidity, pressure and temperature. With the purpose of increasing the output energy of the fuel cell, many flow field designs are being developed continuously. In this paper, the performance of various conventional, modified, hybrid and new flow field designs of the PEMFC is studied in detail. Further the effects of channel tapering, channel bending, landing to channels width ratios, channel cross-sections and insertion of baffles/blockages/pin-fins/inserts are reviewed. The power density of the flow field designs, the physical parameters like active area, dimensions of channel/rib, number of channels; and the operating parameters like temperature and pressure are also tabulated.
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Affiliation(s)
- Muthukumar Marappan
- Fuel Cell Research Lab, Department of Mechanical Engineering, Nandha Engineering College (Autonomous Institution, Affiliated to Anna University), Erode, 638052, India
| | - Karthikeyan Palaniswamy
- Fuel Cell Energy System Lab, Department of Automobile Engineering, PSG College of Technology, Coimbatore, 641004, India
| | - Thiagarajan Velumani
- Fuel Cell Energy System Lab, Department of Automobile Engineering, PSG College of Technology, Coimbatore, 641004, India
| | - Kim Byung Chul
- Electromaterials Science Lab, Department of Printed Electronics Engineering, Sunchon National University, Jungang-Ro 255, SunCheon-Shi, JeollaNam-Do, South Korea
| | - Rajavel Velayutham
- Electromaterials Science Lab, Department of Printed Electronics Engineering, Sunchon National University, Jungang-Ro 255, SunCheon-Shi, JeollaNam-Do, South Korea
| | | | - Senthilarasu Sundaram
- Environment and Sustainability Institute (ESI), University of Exeter Penryn Campus, Penryn, Cornwall, TR10 9FE, UK
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Marappan M, Narayanan R, Manoharan K, Vijayakrishnan MK, Palaniswamy K, Karazhanov S, Sundaram S. Scaling Up Studies on PEMFC Using a Modified Serpentine Flow Field Incorporating Porous Sponge Inserts to Observe Water Molecules. Molecules 2021; 26:molecules26020286. [PMID: 33430043 PMCID: PMC7827057 DOI: 10.3390/molecules26020286] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 01/03/2021] [Accepted: 01/05/2021] [Indexed: 11/16/2022] Open
Abstract
Flooding of the cathode flow channel is a major hindrance in achieving maximum performance from Proton Exchange Membrane Fuel Cells (PEMFC) during the scaling up process. Water accumulated between the interface region of Gas Diffusion Layer (GDL) and rib of the cathode flow field can be removed by the use of Porous Sponge Inserts (PSI) on the ribs. In the present work, the experimental investigations are carried out on PEMFC for the various reaction areas, namely 25, 50 and 100 cm2. Stoichiometry value of 2 is maintained for all experiments to avoid variations in power density obtained due to differences in fuel utilization. The experiments include two flow fields, namely Serpentine Flow Field (SFF) and Modified Serpentine with Staggered provisions of 4 mm PSI (4 mm × 2 mm × 2 mm) Flow Field (MSSFF). The peak power densities obtained on MSSFF are 0.420 W/cm2, 0.298 W/cm2 and 0.232 W/cm2 compared to SFF which yields 0.242 W/cm2, 0.213 W/cm2 and 0.171 W/cm2 for reaction areas of 25, 50 and 100 cm2 respectively. Further, the reliability of experimental results is verified for SFF and MSSFF on 25 cm2 PEMFC by using Electrochemical Impedance Spectroscopy (EIS). The use of 4 mm PSI is found to improve the performance of PEMFC through the better water management.
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Affiliation(s)
- Muthukumar Marappan
- Fuel Cell Research Lab & Department of Mechanical Engineering, Nandha Engineering College, Erode 638052, India;
| | - Rengarajan Narayanan
- Fuel Cell Research Lab & Department of Electrical and Electronics Engineering, Nandha Engineering College, Erode 638052, India;
| | - Karthikeyan Manoharan
- Fuel Cell Energy System Laboratory, Department of Automobile Engineering, PSG College of Technology, Coimbatore 641004, India; (K.M.); (M.K.V.)
| | - Magesh Kannan Vijayakrishnan
- Fuel Cell Energy System Laboratory, Department of Automobile Engineering, PSG College of Technology, Coimbatore 641004, India; (K.M.); (M.K.V.)
| | - Karthikeyan Palaniswamy
- Fuel Cell Energy System Laboratory, Department of Automobile Engineering, PSG College of Technology, Coimbatore 641004, India; (K.M.); (M.K.V.)
- Correspondence: (K.P.); (S.K.); Tel.: +91-944-368-2803 (K.P.)
| | - Smagul Karazhanov
- Department for Solar Energy, Institute for Energy Technology (IFE), 2027 Kjeller, Norway
- Correspondence: (K.P.); (S.K.); Tel.: +91-944-368-2803 (K.P.)
| | - Senthilarasu Sundaram
- Environment and Sustainability Institute (ESI), University of Exeter, Penryn TR10 9EZ, UK;
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Verma A, Palaniswamy K, Cremonini G, Heaton N, Dhawan A. Late cytomegalovirus infection in children: High incidence of allograft rejection and hepatitis in donor negative and seropositive liver transplant recipients. Pediatr Transplant 2017; 21. [PMID: 28134467 DOI: 10.1111/petr.12879] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/13/2016] [Indexed: 12/18/2022]
Abstract
The complications and outcome associated with late CMV infection and disease on the graft are poorly characterized in PLT recipients. We studied the overall incidence, risk factors, and outcome of late CMV infection and disease (infection 6 months after transplant) in 180 PLT recipients admitted between 2008 and 2011 at the King's College Hospital. Antiviral prophylaxis of intravenous ganciclovir was given only to the D+R- group starting at day 7 post-transplant. The remaining groups (D-R+, D+R+, and D-R-) received pre-emptive therapy when they have CMV viremia above cut-off value and treatment for symptomatic CMV infection. The overall incidence of late CMV infection and disease was 9.4% (19/180) and 14.5% (19/130) in D+R-, D-R+, D+R- groups. The D-R+ group had the highest incidence of hepatitis (37.5%) and significantly increased incidence of CMV disease, and single and multiple acute rejection episodes when compared to the D+R- group, which received prophylaxis. The late CMV infection and disease in pediatric LT recipients was comparable to adult LT recipients despite variable duration of antiviral prophylaxis. Our results show that D-R+ group had highest rate of hepatitis and rejection episodes, associated with high morbidity, and should be considered for antiviral prophylaxis.
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Affiliation(s)
- A Verma
- Institute of Liver Studies, King's College Hospital, London, UK
| | - K Palaniswamy
- Pediatric Liver, GI and Nutrition and Institute of Liver Studies, King's College Hospital, London, UK
| | - G Cremonini
- Pediatric Liver, GI and Nutrition and Institute of Liver Studies, King's College Hospital, London, UK
| | - N Heaton
- Institute of Liver Studies, King's College Hospital, London, UK
| | - A Dhawan
- Pediatric Liver, GI and Nutrition and Institute of Liver Studies, King's College Hospital, London, UK
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Arumugam S, Selvaraj SV, Velayutham S, Natesan SK, Palaniswamy K. Evaluation of anti-ulcer activity of Samanea saman (Jacq) merr bark on ethanol and stress induced gastric lesions in albino rats. Indian J Pharmacol 2011; 43:586-90. [PMID: 22022006 PMCID: PMC3195133 DOI: 10.4103/0253-7613.84978] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2010] [Revised: 12/28/2010] [Accepted: 07/01/2011] [Indexed: 12/02/2022] Open
Abstract
Objective: To evaluate the antiulcer activity of Samanea saman (Jacq) Merr bark on ethanol and stress induced gastric lesions in albino rats. Materials and Methods: Gastric lesions were induced in rats by oral administration of absolute ethanol (5 ml/kg) and stress induced by water immersion. The antiulcer activity of methanolic extract of Samanea saman (Jacq) Merr bark (100 mg/kg, 200 mg/kg, 400 mg/kg) was compared with standard drugs. The parameters studied were ulcer index, gastric juice volume, pH, free acidity and total acidity. Result: Samanea saman (Jacq) Merr showed a dose dependent curative ratio compared to ulcer control groups. The extract at 400 mg/kg showed significant anti ulcer activity which is almost equal to that of the standard drug in both models. The volume of acid secretion, total and free acidity was decreased and pH of the gastric juice was increased compared to ulcer control group. Conclusions: The present study indicates that Samanea saman (Jacq) Merr bark extracts have potential anti ulcer activity.
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Affiliation(s)
- Suresh Arumugam
- Department of Pharmacology, JKK Munirajah Medical Research Fountation College of Pharmacy, B. Komarapalayam, Namakkal (dt), Tamil Nadu, India
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