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Joo H, Han SW, Lee CS, Jang HS, Kim ST, Han JS. Field application of cost-effective sensors for the monitoring of NH 3, H 2S, and TVOC in environmental treatment facilities and the estimation of odor intensity. J Air Waste Manag Assoc 2023; 73:50-64. [PMID: 36200828 DOI: 10.1080/10962247.2022.2131652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 08/19/2022] [Accepted: 09/22/2022] [Indexed: 06/16/2023]
Abstract
Odor is usually a complex mixture of various compounds. In many countries, odor complaints have been addressed using the air dilution olfactory method (ADOM) to reduce their malodor complaint. In this study, continuous monitoring of ammonia, hydrogen sulfide, and total volatile organic compounds (TVOC) using sensors was conducted in facilities for municipal and livestock wastewater treatment (LWT), and for food waste composting (FWC). Odor intensity was modeled by multivariate linear regression using sensor monitoring data with air dilution measured by the ADOM. In testing the performance of sensors in the lab, all three sensors showed acceptable values for linearity, accuracy, repeatability, lowest detection limit, and response time, so the sensors were acceptable for application in the field. In on-site real-time monitoring, the three sensors functioned well in the three environmental facilities during the testing period. Average ammonia and hydrogen sulfide concentrations were high in the LWT facility, while TVOC showed the highest concentration in the FWC facility. A longer sampling time is necessary for ammonia monitoring. Odor intensity from individual sensor data correlated well to complex odor measured by the ADOM. Finally, we suggest a protocol for field application of sensor monitoring and odor data reproduction.Implications: We suggest a protocol for the field application of sensor monitoring and odor data estimation in this study. This study can be useful to a policy maker and field operator to reduce odor emission through the determination of a more effective treatment technology and removal pathway for individual odorants.
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Affiliation(s)
- HungSoo Joo
- Department of Environmental Engineering, Anyang University, Anyang-si, Gyeonggi-do, Korea
| | - Sang-Woo Han
- Department of Environmental Engineering, Anyang University, Anyang-si, Gyeonggi-do, Korea
| | - Chun-Sang Lee
- Department of Environmental Engineering, Anyang University, Anyang-si, Gyeonggi-do, Korea
| | - Hyun-Seop Jang
- Zero Emission Center, Sungkyunkwan University, Suwon-si, Gyeonggi-do, Korea
| | - Sung-Tae Kim
- E2M3 Inc, Anyang University, Anyang-si, Gyeonggi-do, Korea
| | - Jin-Seok Han
- Department of Environmental Engineering, Anyang University, Anyang-si, Gyeonggi-do, Korea
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Kim H, Kim J, Joo H, Lee S, Lee S, Yoo K, Youn Y. The Predictive Scoring Systems for Outcomes of Heart Transplantation in Patients with Pre-Existing Liver Cirrhosis. J Heart Lung Transplant 2021. [DOI: 10.1016/j.healun.2021.01.623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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3
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Kim H, Kim J, Lee S, Joo H, Yoo K, Youn Y. Heart Transplantation Outcomes in Liver Cirrhosis: Influence of Ascites on Post-Transplantation Survival. J Heart Lung Transplant 2019. [DOI: 10.1016/j.healun.2019.01.726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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4
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Lee D, Joo H, Jung H, LIM D. Mediation analysis on the association between statin use and fasting glucose level. Atherosclerosis 2018. [DOI: 10.1016/j.atherosclerosis.2018.06.618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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5
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Lee S, Youn Y, Joo H, Kim J. Impact of Preoperative Extracorporeal Membrane Oxygenation Apply on Heart Transplantation. J Heart Lung Transplant 2017. [DOI: 10.1016/j.healun.2017.01.554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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6
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Wang X, Ndegwa PM, Joo H, Neerackal GM, Harrison JH, Stöckle CO, Liu H. Reliable low-cost devices for monitoring ammonia concentrations and emissions in naturally ventilated dairy barns. Environ Pollut 2016; 208:571-579. [PMID: 26552517 DOI: 10.1016/j.envpol.2015.10.031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Revised: 10/17/2015] [Accepted: 10/19/2015] [Indexed: 06/05/2023]
Abstract
This research investigated the use of two relatively cost-effective devices for determining NH3 concentrations in naturally ventilated (NV) dairy barns including an Ogawa passive sampler (Ogawa) and a passive flux sampler (PFS). These samplers were deployed adjacent to sampling ports of a photoacoustic infrared multigas spectroscope (INNOVA), in a NV dairy barn. A 3-day deployment period was deemed suitable for both passive samplers. The correlations between concentrations determined with the passive samplers and the INNOVA were statistically significant (r = 0.93 for Ogawa and 0.88 for PFS). Compared with reference measurements, Ogawa overestimated NH3 concentrations in the barn by ∼ 14%, while PFS underestimated NH3 concentrations by ∼ 41%. Barn NH3 emission factors per animal unit (20.6-21.2 g d(-1) AU(-1)) based on the two passive samplers, after calibration, were similar to those obtained with the reference method and were within the range of values reported in literature.
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Affiliation(s)
- Xiang Wang
- Biological Systems Engineering, Washington State University, PO Box 646120, Pullman, WA 99164, USA
| | - Pius M Ndegwa
- Biological Systems Engineering, Washington State University, PO Box 646120, Pullman, WA 99164, USA.
| | - HungSoo Joo
- Biological Systems Engineering, Washington State University, PO Box 646120, Pullman, WA 99164, USA
| | - George M Neerackal
- Biological Systems Engineering, Washington State University, PO Box 646120, Pullman, WA 99164, USA
| | - Joseph H Harrison
- Animal Science, Washington State University, Puyallup Research and Extension Center, 2606 West Pioneer, Puyallup, WA 98371, USA
| | - Claudio O Stöckle
- Biological Systems Engineering, Washington State University, PO Box 646120, Pullman, WA 99164, USA
| | - Heping Liu
- Civil & Environmental Engineering, Washington State University, PO Box 642910, Pullman, WA 99164, USA
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Joo H, Park K, Lee K, Ndegwa PM. Mass concentration coupled with mass loading rate for evaluating PM(2.5) pollution status in the atmosphere: A case study based on dairy barns. Environ Pollut 2015; 207:374-380. [PMID: 26452004 DOI: 10.1016/j.envpol.2015.09.048] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Revised: 09/23/2015] [Accepted: 09/24/2015] [Indexed: 06/05/2023]
Abstract
This study investigated particulate matter (PM) loading rates and concentrations in ambient air from naturally ventilated dairy barns and also the influences of pertinent meteorological factors, traffic, and animal activities on mass loading rates and mass concentrations. Generally, relationships between PM2.5 concentration and these parameters were significantly poorer than those between the PM loading rate and the same parameters. Although ambient air PM2.5 loading rates correlated well with PM2.5 emission rates, ambient air PM2.5 concentrations correlated poorly with PM2.5 concentrations in the barns. A comprehensive assessment of PM2.5 pollution in ambient air, therefore, requires both mass concentrations and mass loading rates. Emissions of PM2.5 correlated strongly and positively with wind speed, temperature, and solar radiation (R(2) = 0.84 to 0.99) and strongly but negatively with relative humidity (R(2) = 0.93). Animal activity exhibited only moderate effect on PM2.5 emissions, while traffic activity did not significantly affect PM2.5 emissions.
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Affiliation(s)
- HungSoo Joo
- Department of Biological Systems Engineering, Washington State University, PO Box 646120, Pullman, WA 99164, USA; Aerosol Technology and Monitoring Laboratory, School of Environmental Science and Engineering, Gwangju Institute of Science and Technology (GIST), 123 Cheomdan-Gwagiro, Buk-gu, Gwangju 500-712, Republic of Korea
| | - Kihong Park
- Aerosol Technology and Monitoring Laboratory, School of Environmental Science and Engineering, Gwangju Institute of Science and Technology (GIST), 123 Cheomdan-Gwagiro, Buk-gu, Gwangju 500-712, Republic of Korea
| | - Kwangyul Lee
- Aerosol Technology and Monitoring Laboratory, School of Environmental Science and Engineering, Gwangju Institute of Science and Technology (GIST), 123 Cheomdan-Gwagiro, Buk-gu, Gwangju 500-712, Republic of Korea
| | - Pius M Ndegwa
- Department of Biological Systems Engineering, Washington State University, PO Box 646120, Pullman, WA 99164, USA.
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Griesheimer D, Gill D, Nease B, Sutton T, Stedry M, Dobreff P, Carpenter D, Trumbull T, Caro E, Joo H, Millman D. MC21 v.6.0 – A continuous-energy Monte Carlo particle transport code with integrated reactor feedback capabilities. ANN NUCL ENERGY 2015. [DOI: 10.1016/j.anucene.2014.08.020] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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9
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Tseveendee S, Joo H, Park J, Yu C, Hong S, Lim D. Clinical impact of neutrophil gelatinase-associated lipocalin and matrix metallopeptidase-9 level according to plaque morphological characteristics assessed by optical coherence tomography in acute coronary syndrome patients. Atherosclerosis 2015. [DOI: 10.1016/j.atherosclerosis.2015.04.832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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10
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Joo H, Cho J, Park J, Yu C, Hong S, Lim D. Relationship between metabolic syndrome and physical activity and arterial stiffness in obese population. Atherosclerosis 2015. [DOI: 10.1016/j.atherosclerosis.2015.04.880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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11
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Choi S, Choi J, Cui L, Seo H, Kim J, Park C, Joo H, Park J, Hong S, Yu C, Lim D. Mixl1 and Flk1 are key downstream players of activated Wnt/TGF-BETA signaling pathway during dimethyl sulfoxide-induced mesodermal specification in P19 cells. Atherosclerosis 2015. [DOI: 10.1016/j.atherosclerosis.2015.04.338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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12
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Hong S, Joo H, Lim D. Brachial ankle pulse wave velocity is an independent risk factor for coronary artery disease. Atherosclerosis 2014. [DOI: 10.1016/j.atherosclerosis.2014.05.866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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13
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Song JY, Lim SI, Jeoung HY, Choi EJ, Hyun BH, Kim B, Kim J, Shin YK, dela Pena RC, Kim JB, Joo H, An DJ. Prevalence of Classical Swine Fever Virus in Domestic Pigs in South Korea: 1999-2011. Transbound Emerg Dis 2012; 60:546-51. [DOI: 10.1111/j.1865-1682.2012.01371.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Indexed: 11/26/2022]
Affiliation(s)
- J. -Y. Song
- Virus Disease Division; Animal, Plant and Fisheries Quarantine and Inspection Agency; Anyang Gyeonggi-do Korea
| | - S. I. Lim
- Virus Disease Division; Animal, Plant and Fisheries Quarantine and Inspection Agency; Anyang Gyeonggi-do Korea
| | - H. Y. Jeoung
- Virus Disease Division; Animal, Plant and Fisheries Quarantine and Inspection Agency; Anyang Gyeonggi-do Korea
| | - E. -J. Choi
- Virus Disease Division; Animal, Plant and Fisheries Quarantine and Inspection Agency; Anyang Gyeonggi-do Korea
| | - B. -H. Hyun
- Virus Disease Division; Animal, Plant and Fisheries Quarantine and Inspection Agency; Anyang Gyeonggi-do Korea
| | - B. Kim
- Virus Disease Division; Animal, Plant and Fisheries Quarantine and Inspection Agency; Anyang Gyeonggi-do Korea
| | - J. Kim
- Virus Disease Division; Animal, Plant and Fisheries Quarantine and Inspection Agency; Anyang Gyeonggi-do Korea
| | - Y. -K. Shin
- Virus Disease Division; Animal, Plant and Fisheries Quarantine and Inspection Agency; Anyang Gyeonggi-do Korea
| | - R. C. dela Pena
- Virus Disease Division; Animal, Plant and Fisheries Quarantine and Inspection Agency; Anyang Gyeonggi-do Korea
| | - J. B. Kim
- MEDIAN Diagnostic Inc; Chuncheon Gangwon-do Korea
| | - H. Joo
- MEDIAN Diagnostic Inc; Chuncheon Gangwon-do Korea
| | - D. J. An
- Virus Disease Division; Animal, Plant and Fisheries Quarantine and Inspection Agency; Anyang Gyeonggi-do Korea
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Park S, Yoon Y, Kang S, Kim T, Kim Y, Joo H, Kim H, Jeong K, Lee D, Lee S, Chung J, Kim Y. Impact of IL2 and IL2RB Genetic Polymorphisms in Kidney Transplantation. Transplant Proc 2011; 43:2383-7. [DOI: 10.1016/j.transproceed.2011.06.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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15
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Dacey D, Joo H, Peterson B, Haun T. Morphology, mosaics and central projections of diverse ganglion cell populations in macaque retina: Approaching a complete account. J Vis 2009. [DOI: 10.1167/9.14.35] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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16
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Kang SW, Park SJ, Kim YW, Kim YH, Sohn HS, Yoon YC, Joo H, Jeong KH, Lee SH, Lee TW, Ihm CG. Association of MCP-1 and CCR2 polymorphisms with the risk of late acute rejection after renal transplantation in Korean patients. Int J Immunogenet 2008; 35:25-31. [PMID: 18186797 PMCID: PMC2228509 DOI: 10.1111/j.1744-313x.2007.00725.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Among the factors modulating transplant rejection, chemokines and their respective receptors deserve special attention. Increased expression of monocyte chemoattractant protein-1 (MCP-1) and its corresponding receptor (chemokine receptor-2, CCR2) has been implicated in renal transplant rejection. To determine the impact of the MCP-1-2518G and CCR2-64I genotypes on renal allograft function, 167 Korean patients who underwent transplantation over a 25-year period were evaluated. Genomic DNA was genotyped using polymerase chain reaction followed by restriction fragment length polymorphism analysis. Fifty-five (32.9%) patients were homozygous for the MCP-1-2518G polymorphism. Nine (5.4%) patients were homozygous for the CCR2-64I polymorphism. None of the investigated polymorphism showed a significant shift in long-term allograft survival. However, a significant increase was noted for the risk of late acute rejection in recipients who were homozygous for the MCP-1-2518G polymorphism (OR, 2.600; 95% CI, 1.125–6.012; P = 0.022). There was also an association between the MCP-1-2518G/G genotype and the number of late acute rejection episodes (P = 0.024). Although there was no difference in the incidence of rejection among recipients stratified by the CCR2-V64I genotype, recipients with the CCR2-V64I GG genotype in combination with the MCP-1-2518G/G genotype had a significantly higher risk of acute or late acute rejection among the receptor-ligand combinations (P = 0.006, P = 0.008, respectively). The MCP-1 variant may be a marker for risk of late acute rejection in Korean patients.
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Affiliation(s)
- S W Kang
- Department of Nephrology, College of Medicine, Inje University, Busan, South Korea
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Kim S, Won Y, Joo H, Kim S, Ahn H, Kim Y. MP-20.18. Urology 2006. [DOI: 10.1016/j.urology.2006.08.599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Abstract
Porcine organs, cells and tissues provide a viable source of transplants in humans, though there is some concern of public health risk from adaptation of swine infectious agents in humans. Limited information is available on the public health risk of many exogenous swine viruses, and reliable and rapid diagnostic tests are available for only a few of these. The ability of several porcine viruses to cause transplacental fetal infection (parvoviruses, circoviruses, and arteriviruses), emergence or recognition of several new porcine viruses during the last two decades (porcine circovirus, arterivirus, paramyxoviruses, herpesviruses, and porcine respiratory coronavirus) and the immunosuppressed state of the transplant recipients increases the xenozoonoses risk of humans to porcine viruses through transplantation. Much of this risk can be eliminated with vigilance and sustained monitoring along with a better understanding of pathogenesis and development of better diagnostic tests. In this review we present information on selected exogenous viruses, highlighting their characteristics, pathogenesis of viral infections in swine, methods for their detection, and the potential xenozoonoses risk they present. Emphasis has been given in this review to swine influenza virus, paramyxovirus (Nipah virus, Menagle virus, LaPiedad paramyxovirus, porcine paramyxovirus), arterivirus (porcine reproductive and respiratory syndrome virus) and circovirus as either they represent new swine viruses or present the greatest risk. We have also presented information on porcine parvovirus, Japanese encephalitis virus, encephalomyocarditis virus, herpesviruses (pseudorabies virus, porcine lymphotropic herpesvirus, porcine cytomegalovirus), coronaviruses (TGEV, PRCV, HEV, PEDV) and adenovirus. The potential of swine viruses to infect humans needs to be assessed in vitro and in vivo and rapid and more reliable diagnostic methods need to be developed to assure safe supply of porcine tissues and cells for xenotransplantation.
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Affiliation(s)
- P S Paul
- Department of Veterinary and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68588, USA.
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Lee S, Lee S, Hwang S, Joo H, Cha K, Kim H. Application of DNA chip technology for Y chromosome microdeletion test. Fertil Steril 2001. [DOI: 10.1016/s0015-0282(01)02213-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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20
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Chae HJ, Joo H, In MJ. Utilization of brewer's yeast cells for the production of food-grade yeast extract. Part 1: Effects of different enzymatic treatments on solid and protein recovery and flavor characteristics. Bioresour Technol 2001; 76:253-258. [PMID: 11198178 DOI: 10.1016/s0960-8524(00)00102-4] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Yeast extract was produced from brewer's yeast of a beer factory by combined enzymatic treatments using endoprotease, exoprotease, 5'-phosphodiesterase, and adenosine monophosphate (AMP)-deaminase. Effects of enzyme combination, enzyme dosages and treatment sequence on the recovery of solid and protein, flavor and compositional characteristics were investigated. Exoprotease dosage strongly affected the recovery of protein and degree of hydrolysis (DH) and sensory characteristics. When the yeast cells were treated using optimal combination of endoprotease and exoprotease (0.6% Protamex and 0.6% Flavourzyme), high solid recovery (48.3-53.1%) and the best flavor profile were obtained. Among various treatment sequences using multiple enzymes, treatment with protease followed by nuclease resulted in the highest 5'-guanosine monophosphate (5'-GMP) content. The optimal concentrations of both 5'-phosphodiesterase and AMP-deaminase were found to be 0.03%. After treatments using optimal combination of enzyme, enzyme dosages and treatment sequence for four enzymes, a high solid yield of 55.1% and 5'-nucleotides content of 3.67% were obtained.
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Affiliation(s)
- H J Chae
- Department of Food Technology, Hoseo University, Asan 336-795, South Korea.
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21
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Morawski B, Lin Z, Cirino P, Joo H, Bandara G, Arnold FH. Functional expression of horseradish peroxidase in Saccharomyces cerevisiae and Pichia pastoris. Protein Eng 2000; 13:377-84. [PMID: 10835112 DOI: 10.1093/protein/13.5.377] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The ability to engineer proteins by directed evolution requires functional expression of the target polypeptide in a recombinant host suitable for construction and screening libraries of enzyme variants. Bacteria and yeast are preferred, but eukaryotic proteins often fail to express in active form in these cells. We have attempted to resolve this problem by identifying mutations in the target gene that facilitate its functional expression in a given recombinant host. Here we examined expression of HRP in Saccharomyces cerevisiae. Through three rounds of directed evolution by random point mutagenesis and screening, we obtained a 40-fold increase in total HRP activity in the S.cerevisiae culture supernatant compared with wild-type, as measured on ABTS ¿2, 2'-azinobis(3-ethylbenzthiazoline-6-sulfonic acid) (260 units/l/OD(600)). Genes from wild-type and two high-activity clones were expressed in Pichia pastoris, where the total ABTS activity reached 600 units/l/OD(600) in shake flasks. The mutants show up to 5.4-fold higher specific activity towards ABTS and 2.3-fold higher specific activity towards guaiacol.
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Affiliation(s)
- B Morawski
- Division of Chemistry and Chemical Engineering 210-41, California Institute of Technology, Pasadena, CA 91125, USA
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22
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Abstract
BACKGROUND Oxygenases catalyze the hydroxylation of a wide variety of organic substrates. An ability to alter oxygenase substrate specificities and improve their activities and stabilities using recombinant DNA techniques would expand their use in processes such as chemical synthesis and bioremediation. Discovery and directed evolution of oxygenases require efficient screens that are sensitive to the activities of interest and can be applied to large numbers of crude enzyme samples. RESULTS Horseradish peroxidase (HRP) couples the phenolic products of hydroxylation of aromatic substrates to generate colored and/or fluorescent compounds that are easily detected spectroscopically in high-throughput screening. Coexpression of the coupling enzyme with a functional mono- or dioxygenase creates a pathway for the conversion of aromatic substrates into fluorescent compounds in vivo. We used this approach for detecting the products of the toluene-dioxygenase-catalyzed hydroxylation of chlorobenzene and to screen large mutant libraries of Pseudomonas putida cytochrome P450cam by fluorescence digital imaging. Colors generated by the HRP coupling reaction are sensitive to the site of oxygenase-catalyzed hydroxylation, allowing the screen to be used to identify catalysts with new or altered regiospecificities. CONCLUSIONS The coupled oxygenase-peroxidase reaction system is well suited for screening oxygenase libraries to identify mutants with desired features, including higher activity or stability and altered reaction specificity. This approach should also be useful for screening expressed DNA libraries and combinatorial chemical libraries for hydroxylation catalysts and for optimizing oxygenase reaction conditions.
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Affiliation(s)
- H Joo
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
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Abstract
Enzyme-based chemical transformations typically proceed with high selectivity under mild conditions, and are becoming increasingly important in the pharmaceutical and chemical industries. Cytochrome P450 monooxygenases (P450s) constitute a large family of enzymes of particular interest in this regard. Their biological functions, such as detoxification of xenobiotics and steroidogenesis, are based on the ability to catalyse the insertion of oxygen into a wide variety of compounds. Such a catalytic transformation might find technological applications in areas ranging from gene therapy and environmental remediation to the selective synthesis of pharmaceuticals and chemicals. But relatively low turnover rates (particularly towards non-natural substrates), low stability and the need for electron-donating cofactors prohibit the practical use of P450s as isolated enzymes. Here we report the directed evolution of the P450 from Pseudomonas putida to create mutants that hydroxylate naphthalene in the absence of cofactors through the 'peroxide shunt' pathway with more than 20-fold higher activity than the native enzyme. We are able to screen efficiently for improved mutants by coexpressing them with horseradish peroxidase, which converts the products of the P450 reaction into fluorescent compounds amenable to digital imaging screening. This system should allow us to select and develop mono- and di-oxygenases into practically useful biocatalysts for the hydroxylation of a wide range of aromatic compounds.
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Affiliation(s)
- H Joo
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena 91125, USA
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Abstract
PURPOSE The Laryngeal Mask Airway-Fastrach (Fastrach) is a new modified laryngeal mask with the capability for guided tracheal intubation while maintaining ventilation. We report the use of this device in patients with proven difficult airways, following induction of general anaesthesia. CLINICAL FEATURES After induction of general anaesthesia, having failed tracheal intubation with conventional laryngoscopy, the first patient's trachea was intubated via the Fastrach with fibreoptic guidance. In the second and third patients, who had documented histories of difficult tracheal intubation, tracheal intubation was performed electively with the Fastrach following induction of inhalational anaesthesia with spontaneous respiration. CONCLUSION The Fastrach is an option in the management of the airway following failed tracheal intubation or for elective tracheal intubation in patients with anatomically difficult airways.
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Affiliation(s)
- H Joo
- Department of Anaesthesia, St. Michael's Hospital, University of Toronto, Ontario
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Abstract
Various methods for the control of PRRS virus have been published. The technology of nursery depopulation (ND) appears to effectively control the spread of virus between members of endemically infected populations. ND consists of a strategic adjustment in pigflow based on the presence of specific serologic patterns as detected by the indirect fluorescent antibody test. This pattern indicates a low seroprevalence of antibodies detected in the breeding herd and recently weaned piglets (< or = 10%), in contrast to a high (> 50%) seroprevalence in 8 to 10 week old piglets. ND has been carried out on swine farms in the US and results indicate improvements in nursery piglet growth rate and mortality levels. Three examples are provided in the following text. Recently a modified live virus vaccine (RespPRRS, NOBL Laboratories/Boerhinger Ingleheim) has become commercially available. It is currently approved for use in piglets from 3 to 18 weeks of age; however, potential for the use in adult animals is currently under investigation.
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Affiliation(s)
- S A Dee
- Swine Health Center, Morris, MN 56267, USA
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Goldstein KP, Philipson TJ, Joo H, Daum RS. The effect of epidemic measles on immunization rates. JAMA 1996; 276:56-8. [PMID: 8667540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
OBJECTIVE To evaluate whether immunization against a vaccine-preventable disease is sought to avoid the naturally occurring disease itself, we hypothesized that the rate of "on-time" measles immunization would increase during an epidemic of that disease. If such an effect occurred, we wondered whether it would have an impact on on-time administration of other recommended immunizations. DESIGN Retrospective evaluation of immunization rates of children at their second birthday with the use of computerized health records of children entering kindergarten in an 8-year interval spanning the onset of epidemic measles in Chicago, Ill, in 1989 and 1990. SETTING Children entering Chicago public schools. MAIN OUTCOME MEASURES Rates of receipt of measles-containing vaccine (MCV), 1 to 4 doses of a diptheria toxoid-tetanus toxoid-pertussis (DTP) or diphtheria toxoid-tetanus toxoid (DT) vaccine, 1 to 3 doses of oral or inactivated polio vaccine (OPV/IPV), and the full series of these vaccines (4:3:1) that are required to be "up-to-date" by the second birthday. RESULTS The rate of on-time MCV receipt increased from 56% to 58% in the years prior to 70% during the epidemic (1989 and 1990). A similar increase did not occur to DTP/DT 4 or OPV/IPV 3. Moreover, among older children delayed in MCV receipt, evidence of catch-up immunization also occurred during the epidemic years; similar catch-up for delayed DTP/DT 4 or OPV/IPV 3 immunization did not occur. CONCLUSIONS Dramatic increases in one-time and catch-up MCV receipt occurred during the Chicago measles epidemic of 1989 and 1990. The lack of similar increases in DTP/DT 4 and OPV/IPV 3 suggests MCV receipt was not associated with receipt of other recommended immunizations during that time.
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Affiliation(s)
- K P Goldstein
- Department of Pediatrics, University of Chicago, IL, USA
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