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Wang YD, Meyer Q, Tang K, McClure JE, White RT, Kelly ST, Crawford MM, Iacoviello F, Brett DJL, Shearing PR, Mostaghimi P, Zhao C, Armstrong RT. Large-scale physically accurate modelling of real proton exchange membrane fuel cell with deep learning. Nat Commun 2023; 14:745. [PMID: 36788206 PMCID: PMC9929041 DOI: 10.1038/s41467-023-35973-8] [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: 08/11/2022] [Accepted: 01/10/2023] [Indexed: 02/16/2023] Open
Abstract
Proton exchange membrane fuel cells, consuming hydrogen and oxygen to generate clean electricity and water, suffer acute liquid water challenges. Accurate liquid water modelling is inherently challenging due to the multi-phase, multi-component, reactive dynamics within multi-scale, multi-layered porous media. In addition, currently inadequate imaging and modelling capabilities are limiting simulations to small areas (<1 mm2) or simplified architectures. Herein, an advancement in water modelling is achieved using X-ray micro-computed tomography, deep learned super-resolution, multi-label segmentation, and direct multi-phase simulation. The resulting image is the most resolved domain (16 mm2 with 700 nm voxel resolution) and the largest direct multi-phase flow simulation of a fuel cell. This generalisable approach unveils multi-scale water clustering and transport mechanisms over large dry and flooded areas in the gas diffusion layer and flow fields, paving the way for next generation proton exchange membrane fuel cells with optimised structures and wettabilities.
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Affiliation(s)
- Ying Da Wang
- grid.1005.40000 0004 4902 0432School of Minerals and Energy Resources Engineering, University of New South Wales, Sydney, NSW 2052 Australia
| | - Quentin Meyer
- School of Chemistry, University of New South Wales, Sydney, NSW, 2052, Australia.
| | - Kunning Tang
- grid.1005.40000 0004 4902 0432School of Minerals and Energy Resources Engineering, University of New South Wales, Sydney, NSW 2052 Australia
| | - James E. McClure
- grid.438526.e0000 0001 0694 4940National Security Institute, Virginia Tech, Blacksburg, VA 24061 USA
| | - Robin T. White
- Carl Zeiss X-ray Microscopy, ZEISS Innovation Center California, Dublin, CA 94568 USA
| | - Stephen T. Kelly
- Carl Zeiss X-ray Microscopy, ZEISS Innovation Center California, Dublin, CA 94568 USA
| | | | - Francesco Iacoviello
- grid.83440.3b0000000121901201Electrochemical Innovation Lab, Department of Chemical Engineering, University College London, London, WC1E 7JE UK
| | - Dan J. L. Brett
- grid.83440.3b0000000121901201Electrochemical Innovation Lab, Department of Chemical Engineering, University College London, London, WC1E 7JE UK
| | - Paul R. Shearing
- grid.83440.3b0000000121901201Electrochemical Innovation Lab, Department of Chemical Engineering, University College London, London, WC1E 7JE UK
| | - Peyman Mostaghimi
- grid.1005.40000 0004 4902 0432School of Minerals and Energy Resources Engineering, University of New South Wales, Sydney, NSW 2052 Australia
| | - Chuan Zhao
- School of Chemistry, University of New South Wales, Sydney, NSW, 2052, Australia.
| | - Ryan T. Armstrong
- grid.1005.40000 0004 4902 0432School of Minerals and Energy Resources Engineering, University of New South Wales, Sydney, NSW 2052 Australia
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2
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Kang V, White RT, Chen S, Federle W. Extreme suction attachment performance from specialised insects living in mountain streams (Diptera: Blephariceridae). eLife 2021; 10:e63250. [PMID: 34731079 PMCID: PMC8565926 DOI: 10.7554/elife.63250] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 09/24/2021] [Indexed: 01/05/2023] Open
Abstract
Suction is widely used by animals for strong controllable underwater adhesion but is less well understood than adhesion of terrestrial climbing animals. Here we investigate the attachment of aquatic insect larvae (Blephariceridae), which cling to rocks in torrential streams using the only known muscle-actuated suction organs in insects. We measured their attachment forces on well-defined rough substrates and found that their adhesion was less reduced by micro-roughness than that of terrestrial climbing insects. In vivo visualisation of the suction organs in contact with microstructured substrates revealed that they can mould around large asperities to form a seal. We have shown that the ventral surface of the suction disc is covered by dense arrays of microtrichia, which are stiff spine-like cuticular structures that only make tip contact. Our results demonstrate the impressive performance and versatility of blepharicerid suction organs and highlight their potential as a study system to explore biological suction mechanisms.
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Affiliation(s)
- Victor Kang
- Department of Zoology, University of CambridgeCambridgeUnited Kingdom
| | - Robin T White
- Carl Zeiss Research Microscopy SolutionsPleasantonUnited Kingdom
| | - Simon Chen
- Department of Zoology, University of CambridgeCambridgeUnited Kingdom
| | - Walter Federle
- Department of Zoology, University of CambridgeCambridgeUnited Kingdom
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Grant T, McIntyre V, Vestfrid J, Raboui H, White RT, Lu ZH, Lessard BH, Bender TP. Straightforward and Relatively Safe Process for the Fluoride Exchange of Trivalent and Tetravalent Group 13 and 14 Phthalocyanines. ACS Omega 2019; 4:5317-5326. [PMID: 31459702 PMCID: PMC6649288 DOI: 10.1021/acsomega.8b03202] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 02/14/2019] [Indexed: 06/10/2023]
Abstract
To avoid the use of hydrofluoric acid, a series of fluorinated trivalent and tetravalent metal-containing phthalocyanines (MPcs) were synthesized using a straightforward one-step halide substitution process using cesium fluoride (CsF) as the fluoride source and by reflux in N,N-dimethylformamide for less than an hour. The resulting fluoro MPcs were characterized and compared to the parent chloro MPcs. In some cases, very little change in properties was observed between the fluoro MPcs and the chloro MPcs. In other cases, such as fluoro aluminum phthalocyanine, a blue shift in the absorbance characteristics and an increase in oxidation and reduction potential of as much as 0.22 V was observed compared to the chloro derivative. Thermo gravimetric analysis was performed on all halo-MPcs, indicating that the choice of halo substitution on the axial position can have an effect on the decomposition or sublimation temperature of the final compound. After initial establishment and characterization of the fluoro MPcs, the halide substitution reaction of difluoro silicon phthalocyanine (F2-SiPc) was further explored by scaling the reaction up to a gram scale as well as considering tetrabutylammonium fluoride (TBAF) as an additional safe fluoride source. The scaled-up reactions producing F2-SiPc using CsF and TBAF as fluoride exchange sources were successfully reproducible, resulting in reaction yields of 100 and 73%, respectively. Both processes led to pure final products but results indicate that CsF, as the fluoride exchange reagent, appears to be the superior reaction process as it has a much higher yield.
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Affiliation(s)
- Trevor
M. Grant
- Department
of Chemical & Biological Engineering, University of Ottawa, 161 Louis Pasteur, Ottawa, Ontario K1N 6N5, Canada
| | - Victoria McIntyre
- Department
of Chemical & Biological Engineering, University of Ottawa, 161 Louis Pasteur, Ottawa, Ontario K1N 6N5, Canada
- Department
of Chemical Engineering & Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada
| | - Jenya Vestfrid
- Department
of Chemical Engineering & Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada
| | - Hasan Raboui
- Department
of Chemical Engineering & Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada
| | - Robin T. White
- Department
of Materials Science and Engineering, University
of Toronto, 180 College Street, Toronto, Ontario M5S 3E5, Canada
| | - Zheng-Hong Lu
- Department
of Materials Science and Engineering, University
of Toronto, 180 College Street, Toronto, Ontario M5S 3E5, Canada
| | - Benoît H. Lessard
- Department
of Chemical & Biological Engineering, University of Ottawa, 161 Louis Pasteur, Ottawa, Ontario K1N 6N5, Canada
| | - Timothy P. Bender
- Department
of Chemical Engineering & Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada
- Department
of Materials Science and Engineering, University
of Toronto, 180 College Street, Toronto, Ontario M5S 3E5, Canada
- Department
of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
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White RT, Eberhardt SH, Singh Y, Haddow T, Dutta M, Orfino FP, Kjeang E. Four-dimensional joint visualization of electrode degradation and liquid water distribution inside operating polymer electrolyte fuel cells. Sci Rep 2019; 9:1843. [PMID: 30755635 PMCID: PMC6372714 DOI: 10.1038/s41598-018-38464-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [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] [Received: 07/13/2018] [Accepted: 12/20/2018] [Indexed: 11/08/2022] Open
Abstract
Understanding of degradation mechanisms present in polymer electrolyte fuel cells (PEFCs) is important to continue the integration of this clean energy technology into everyday life. Further comprehension of the interaction between various components during fuel cell operation is also critical in this context. In this work, a four-dimensional operando X-ray computed tomography method is developed for combined visualization of all PEFC components as well as transient water distribution residing in the cell, which results as a by-product of the electrochemical reaction. Time resolved, identical-location visualization through degradation stages is uniquely enabled by the non-invasive and non-destructive qualities of this method. By applying an accelerated stress test that targets cathode catalyst layer (CCL) corrosion, novel observations resulting from morphological changes of the CCL such as reduction in the water volume in the adjacent gas diffusion layer, CCL crack formation and propagation, membrane swelling, as well as quantification of local carbon loss is achieved. Additionally, insight into features that contribute to reduced fuel cell performance is enabled by the use of this specialized imaging technique, such as increased membrane undulation causing delamination and separation of the CCL from the microporous layer, which greatly affects liquid water pathways and overall device performance.
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Affiliation(s)
- Robin T White
- Fuel Cell Research Laboratory (FCReL), School of Mechatronic Systems Engineering, Simon Fraser University, 250-13450 102 Avenue, Surrey, BC, V3T 0A3, Canada
| | - Sebastian H Eberhardt
- Fuel Cell Research Laboratory (FCReL), School of Mechatronic Systems Engineering, Simon Fraser University, 250-13450 102 Avenue, Surrey, BC, V3T 0A3, Canada
| | - Yadvinder Singh
- Fuel Cell Research Laboratory (FCReL), School of Mechatronic Systems Engineering, Simon Fraser University, 250-13450 102 Avenue, Surrey, BC, V3T 0A3, Canada
| | - Tylynn Haddow
- Fuel Cell Research Laboratory (FCReL), School of Mechatronic Systems Engineering, Simon Fraser University, 250-13450 102 Avenue, Surrey, BC, V3T 0A3, Canada
| | - Monica Dutta
- Ballard Power Systems, 9000 Glenlyon Parkway, Burnaby, BC, V5J 5J8, Canada
| | - Francesco P Orfino
- Fuel Cell Research Laboratory (FCReL), School of Mechatronic Systems Engineering, Simon Fraser University, 250-13450 102 Avenue, Surrey, BC, V3T 0A3, Canada
| | - Erik Kjeang
- Fuel Cell Research Laboratory (FCReL), School of Mechatronic Systems Engineering, Simon Fraser University, 250-13450 102 Avenue, Surrey, BC, V3T 0A3, Canada.
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Lessard BH, White RT, Al-Amar M, Plint T, Castrucci JS, Josey DS, Lu ZH, Bender TP. Assessing the potential roles of silicon and germanium phthalocyanines in planar heterojunction organic photovoltaic devices and how pentafluoro phenoxylation can enhance π-π interactions and device performance. ACS Appl Mater Interfaces 2015; 7:5076-5088. [PMID: 25665015 DOI: 10.1021/am508491v] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In this study, we have assessed the potential application of dichloro silicon phthalocyanine (Cl2-SiPc) and dichloro germanium phthalocyanine (Cl2-GePc) in modern planar heterojunction organic photovoltaic (PHJ OPV) devices. We have determined that Cl2-SiPc can act as an electron donating material when paired with C60 and that Cl2-SiPc or Cl2-GePc can also act as an electron acceptor material when paired with pentacene. These two materials enabled the harvesting of triplet energy resulting from the singlet fission process in pentacene. However, contributions to the generation of photocurrent were observed for Cl2-SiPc with no evidence of photocurrent contribution from Cl2-GePc. The result of our initial assessment established the potential for the application of SiPc and GePc in PHJ OPV devices. Thereafter, bis(pentafluoro phenoxy) silicon phthalocyanine (F10-SiPc) and bis(pentafluoro phenoxy) germanium phthalocyanine (F10-GePc) were synthesized and characterized. During thermal processing, it was discovered that F10-SiPc and F10-GePc underwent a reaction forming small amounts of difluoro SiPc (F2-SiPc) and difluoro GePc (F2-GePc). This undesirable reaction could be circumvented for F10-SiPc but not for F10-GePc. Using single crystal X-ray diffraction, it was determined that F10-SiPc has significantly enhanced π-π interactions compared with that of Cl2-SiPc, which had little to none. Unoptimized PHJ OPV devices based on F10-SiPc were fabricated and directly compared to those constructed from Cl2-SiPc, and in all cases, PHJ OPV devices based on F10-SiPc had significantly improved device characteristics compared to Cl2-SiPc.
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Affiliation(s)
- Benoît H Lessard
- Department of Chemical Engineering and Applied Chemistry, University of Toronto , 200 College Street, Toronto, Ontario M5S 3E5, Canada
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Stanton LW, Garrard LJ, Damm D, Garrick BL, Lam A, Kapoun AM, Zheng Q, Protter AA, Schreiner GF, White RT. Altered patterns of gene expression in response to myocardial infarction. Circ Res 2000; 86:939-45. [PMID: 10807865 DOI: 10.1161/01.res.86.9.939] [Citation(s) in RCA: 257] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The use of cDNA microarrays has made it possible to simultaneously analyze gene expression for thousands of genes. Microarray technology was used to evaluate the expression of >4000 genes in a rat model of myocardial infarction. More than 200 genes were identified that showed differential expression in response to myocardial infarction. Gene expression changes were monitored from 2 to 16 weeks after infarction in 2 regions of the heart, the left ventricle free wall and interventricular septum. A novel clustering program was used to identify patterns of expression within this large set of data. Unique patterns were revealed within the transcriptional responses that illuminate changes in biological processes associated with myocardial infarction.
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White RT, Walden MA. Obstacles to a randomised controlled trial of intensive dynamic psychotherapy: an account of the New South Wales Section of Psychotherapy outcomes project. Aust N Z J Psychiatry 2000; 34:271-8. [PMID: 10789532 DOI: 10.1080/j.1440-1614.2000.00717.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
OBJECTIVE This paper examines the obstacles to a randomised controlled trial (RCT) of intensive dynamic psychotherapy (IDP) by reference to the fate of the New South Wales Section of Psychotherapy outcomes project. METHOD Planning was complete and the final research protocol was about to be implemented when funding difficulties led to suspension of the project. The opinions of the research subcommittee regarding the main obstacles to the ultimate success of the project are now analysed in the expectation that better research strategies will follow. RESULTS With hindsight, six of the eight members of the research subcommittee reported that the project was not feasible. By choice of questionnaire items they identified the greatest threats to a successful trial as: standardisation of the procedures, termination at 24 months, the availability of funding and the choice of treatment procedures. The most frequently volunteered concerns related to the enlistment and cooperation of the trial therapists (5), standardisation of the experimental therapy (3), probable shortfall in trial subjects (3) and the availability of funding (2). CONCLUSIONS The most powerful general obstacles to success of the project related to the standardisation of procedures and the failure to maintain sufficient cooperation of trial therapists. The protocol required IDP therapists to terminate procedures at 24 months, which contradicted their usual practices and led to some alienation from the project. Amendments to the protocol might improve the possibility of a successful trial. However, one might also conclude that it is premature to attempt a naturalistic RCT of IDP.
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Affiliation(s)
- R T White
- Royal Prince Alfred Hospital, Camperdown, New South Wales, Australia.
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9
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White RT, Stedman T. Evidence-based medicine offers little support for psychosurgery. Aust N Z J Psychiatry 1998; 32:460-3. [PMID: 9672740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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10
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White RT. When the next influenza pandemic comes. BMJ 1997; 315:204. [PMID: 9253260 PMCID: PMC2127166 DOI: 10.1136/bmj.315.7102.204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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McKinnie IT, Gloster LA, King TA, White RT. Excitation of a Cr:forsterite laser to the (3)T(1) band. Appl Opt 1997; 36:4985-4988. [PMID: 18259304 DOI: 10.1364/ao.36.004985] [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] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Laser oscillation of Cr:forsterite was obtained with ruby laser pumping to the lowest-lying levels of the (3)T(1) band in Cr(4+). Pump polarization effects, temporal response, and broadband 220-nm tuning are reported. Frequency doubling in potassium titanyl phosphate generate tunable red-yellow light. This unconventional excitation scheme is of interest for potential high-energy output and for direct diode pumping.
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12
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White RT. Measurement of autobiographical recall. Percept Mot Skills 1997; 84:34. [PMID: 9132729 DOI: 10.2466/pms.1997.84.1.34] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The finding by Huffman and Weaver (1996) of no support for the hypothesis that personal episodic recall involves visual imagery may be a consequence of their method of assessment. Further research which employs more measures than simply number of events recalled and which gives subjects longer time to respond is needed.
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Affiliation(s)
- R T White
- Faculty of Education, Monash University, Clayton, Melbourne, Victoria, Australia
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13
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Abstract
Jumping is the most common reported means of suicide in general hospitals. There have been no published reviews of suicides of nonpsychiatric inpatients since 1980. We describe 12 subjects who, between January 1980 and January 1992, jumped from a large general teaching hospital. Eight of them succumbed, providing a rate of suicide of 1.7 per 100,000 admissions. There were three clinical subgroups: those admitted after suicide attempts, the acutely delirious, and the chronically medically ill. Factors appearing frequently in the third subgroup were pain, dyspnea, transient confusion, poor prognosis, and recent adverse news. When we compared the hospital jumpers with 30 nonfatal jumpers who attended our Emergency Department, the medical and psychiatric profiles differed in the frequency of medical illnesses, advancing age, male gender, and absence of preexisting psychiatric illness. Proximity and ease of access to balconies and windows appeared to be highly relevant to the prevention of hospital jumping.
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Affiliation(s)
- R T White
- Department of Psychiatry, Royal Prince Alfred Hospital, New South Wales, Australia
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14
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Venkatesh VC, Planer BC, Schwartz M, Vanderbilt JN, White RT, Ballard PL. Characterization of the promoter of human pulmonary surfactant protein B gene. Am J Physiol 1995; 268:L674-82. [PMID: 7733308 DOI: 10.1152/ajplung.1995.268.4.l674] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Pulmonary surfactant protein B (SP-B) is required for normal surfactant function and for survival at birth. To further study SP-B gene expression, we sequenced genomic clones and examined promoter activity of SP-B DNA fragments by transient transfection. A plasmid construct containing human SP-B fragment -1039/+431 linked to chloramphenicol acetyltransferase (CAT) reporter gene was readily expressed in H441 cells, which are derived from a human lung adenocarcinoma, but was < 4% as active in Hep G2, HeLa, and Calu 6 cell lines. SP-B promoter activity in H441 cells was orientation dependent and increased by linked Rous sarcoma virus (RSV) enhancer and was stronger than for thymidine kinase (tk) and RSV promoters. Deletional mapping of the 5' flanking region with exonuclease III suggested nonspecific negative (-811/-1039)- and positive (-453/-641)-control regions and a cell-specific enhancer region at -208 to -54. When a fragment from -403 to -35 base pairs (bp) was placed upstream or downstream of tkCAT, in either orientation, expression in H441 cells but not other cell lines was increased 4- to 28-fold relative to tkCAT. Deletional analysis of the 3' terminus indicated a requirement for at least 7 bp 3' of the transcription start site. Promoter activity was strongly inhibited in a dose-dependent fashion by phorbol ester, with responsiveness mapped to bp -208/-54, but was not responsive to glucocorticoid.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- V C Venkatesh
- Department of Pediatrics, University of Pennsylvania, Children's Hospital of Philadelphia 19104, USA
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Abstract
Cow stomach lysozyme genes have evolved in a mosaic pattern. The majority of the intronic and flanking sequences show an amount of sequence difference consistent with divergent evolution since duplication of the genes 40-50 million years ago. In contrast, exons 1, 2, and 4 and immediately adjacent intronic sequences differ little between genes and show evidence of recent concerted evolution. Exon 3 appears to be evolving divergently. The three characterized genes vary from 5.6 to 7.9 kilobases in length. Different distributions of repetitive DNA are found in each gene, which accounts for the majority of length differences between genes. The different distributions of repetitive DNA in each gene suggest the repetitive elements were inserted into each gene after the duplications that give rise to these three genes and provide additional support for divergent evolution for the majority of each gene. The observation that intronic and flanking sequences are evolving divergently suggests that the concerted evolution events involved in homogenizing the coding regions of lysozyme genes involve only one exon at a time. This model of concerted evolution would allow the shuffling of exon-sized pieces of information between genes, a phenomenon that may have aided in the early adaptive evolution of stomach lysozyme.
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Affiliation(s)
- D M Irwin
- Division of Biochemistry and Molecular Biology, University of California, Berkeley 94720
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Endemann G, Stanton LW, Madden KS, Bryant CM, White RT, Protter AA. CD36 is a receptor for oxidized low density lipoprotein. J Biol Chem 1993; 268:11811-6. [PMID: 7685021] [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] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The oxidation of low density lipoprotein (LDL) in the arterial wall is thought to contribute to human atherosclerotic lesion formation, in part by the high affinity uptake of oxidized LDL (OxLDL) by macrophages, resulting in foam cell formation. We have utilized cloning by expression to identify CD36 as a macrophage receptor for OxLDL. Transfection of a CD36 clone into 293 cells results in the specific and high affinity binding of OxLDL, followed by its internalization and degradation. An anti-CD36 antibody blocks 50% of the binding of OxLDL to platelets and to human macrophage-like THP cells. Furthermore, like mouse macrophages, 293 cells expressing CD36 recognize LDL which has been oxidized only 4 h, whereas more extensive oxidation of the LDL is required for recognition by the other known OxLDL receptors, the acetylated LDL (AcLDL) receptor and Fc gamma RII-B2. CD36 may play a role in scavenging LDL modified by oxidation and may mediate effects of OxLDL on monocytes and platelets in atherosclerotic lesions.
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Affiliation(s)
- G Endemann
- Scios Nova Inc., Mountain View, California 94043
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Stanton LW, White RT, Bryant CM, Protter AA, Endemann G. A macrophage Fc receptor for IgG is also a receptor for oxidized low density lipoprotein. J Biol Chem 1992; 267:22446-51. [PMID: 1429595] [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] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The internalization of oxidized low density lipoprotein (OxLDL) by macrophages is hypothesized to contribute to foam cell formation and eventually to atherosclerotic lesion formation. OxLDL is a ligand for the acetylated low density lipoprotein (AcLDL) receptor, however, our data show that this receptor accounts for less than half of OxLDL uptake by mouse macrophages, suggesting additional receptors for OxLDL. We have developed a novel expression cloning strategy in order to isolate clones encoding OxLDL receptors. In addition to the AcLDL receptor, we isolated a molecular clone for a structurally unrelated receptor capable of mediating the high affinity uptake of OxLDL following transfection into cells. This receptor has been identified as the mouse Fc gamma RII-B2, a member of a family of receptors known to mediate immune complex uptake through recognition of the Fc region of IgG. The uptake of OxLDL by cells transfected with the Fc gamma RII-B2 clone is not blocked by AcLDL but is blocked by the anti-Fc gamma RII monoclonal antibody, 2.4G2.
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Affiliation(s)
- L W Stanton
- Scios Incorporated, Mountain View, California 94043
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18
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White RT, Damm D, Hancock N, Rosen BS, Lowell BB, Usher P, Flier JS, Spiegelman BM. Human adipsin is identical to complement factor D and is expressed at high levels in adipose tissue. J Biol Chem 1992; 267:9210-3. [PMID: 1374388] [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] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
A cDNA for human adipsin was isolated and shown to encode a protein sharing 98% amino acid sequence similarity with the protein sequence previously determined for purified natural human complement factor D. Like mouse adipsin, recombinant human adipsin displays the enzymatic activity of human complement factor D, cleaving complement factor B only when B is complexed with activated complement component C3. We conclude that human adipsin is equivalent to complement factor D and that adipsin is the homologue of factor D in rodents. Adipose tissue is a major site of synthesis of human adipsin/complement factor D mRNA, but unlike the case in rodents, human adipsin mRNA is also expressed in monocytes/macrophages. The data presented here, demonstrating the equivalence of human adipsin to complement factor D and its high level of expression in fat, suggest a previously unsuspected role for adipose tissue in immune system biology.
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Affiliation(s)
- R T White
- California Biotechnology Inc., Mountain View 94043
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19
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Ballard PL, Liley HG, Gonzales LW, Odom MW, Ammann AJ, Benson B, White RT, Williams MC. Interferon-gamma and synthesis of surfactant components by cultured human fetal lung. Am J Respir Cell Mol Biol 1990; 2:137-43. [PMID: 2106332 DOI: 10.1165/ajrcmb/2.2.137] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
We examined the effects of interferon-gamma (IFN-gamma) on development of the surfactant system in alveolar epithelial cells of fetal lung. Explants of second-trimester human fetal lung were cultured for 1 to 6 days in serum-free medium containing recombinant human IFN-gamma (0.03 to 30 ng/ml) and/or dexamethasone (10 or 100 nM). Treatment for 3 days with IFN-gamma alone, dexamethasone alone, and IFN plus dexamethasone increased the content of surfactant protein A (SP-A, 28 to 36 kD) by approximately 3-, 2.5-, and 10-fold, respectively. The biphasic response pattern of SP-A to dexamethasone (stimulation initially and inhibition with continued culture) was not altered by the presence of IFN-gamma. IFN-gamma also stimulated accumulation of SP-A mRNA (2.7-fold at 24 h) but did not affect the levels of mRNAs for surfactant protein B (18 kD) and surfactant protein C (5 kD). To assess the effect of IFN-gamma on synthesis of surfactant lipids, we determined the content of phosphatidylcholine, the rate of labeled choline incorporation into phosphatidylcholine, saturation of newly synthesized phosphatidylcholine, and the activity of fatty acid synthetase, a glucocorticoid-inducible enzyme. Treatment of explants for 5 days with IFN-gamma had no effect on these parameters. Studies by light and electron microscopy revealed little difference between control and IFN-treated explants with regard to cell viability and epithelial cell differentiation. We conclude that IFN-gamma has a selective stimulatory effect on SP-A among surfactant components.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- P L Ballard
- Department of Pediatrics and Anatomy, University of California, San Francisco 94143
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20
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Haagsman HP, White RT, Schilling J, Lau K, Benson BJ, Golden J, Hawgood S, Clements JA. Studies of the structure of lung surfactant protein SP-A. Am J Physiol 1989; 257:L421-9. [PMID: 2610270 DOI: 10.1152/ajplung.1989.257.6.l421] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
SP-A, a glycoprotein of pulmonary surfactant, consists of an NH2-terminal domain containing a collagen-like sequence and a COOH-terminal domain with sequence homology to several Ca2(+)-dependent lectins. We have compared the size, thermal stability, and secondary structure of recombinant SP-A, the product of a fibroblast line transfected with a single human gene encoding SP-A, with natural SP-A isolated from canine and human lungs. Our results suggest both recombinant and natural SP-A are assembled as large oligomers. More variability in the degree of oligomerization was observed with recombinant human SP-A than with natural canine SP-A. As shown by collagenase digestion, the full assembly of protein subunits was dependent on an intact collagen-like domain. The cysteines in the noncollagen domain of SP-A form intrachain bonds between residues 135-226 and 204-218. The circular dichroism spectra of both recombinant and natural SP-A were consistent with the presence of a collagen-like triple helix. As determined by the change in ellipticity at 205 nm, the thermal transition temperatures of canine, natural human, and recombinant SP-A were 51.5, 52.3, and 42.0 degrees C, respectively. These results suggest differences in the assembly and stability of the natural and recombinant proteins.
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Affiliation(s)
- H P Haagsman
- Department of Pediatrics, University of California, San Francisco 94143
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21
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Gribble R, White RT, Wicks G, Reed J, Kurt J. The psychiatric nurse in liaison psychiatry. Aust N Z J Psychiatry 1989; 23:309-11. [PMID: 2803139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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22
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Liley HG, White RT, Warr RG, Benson BJ, Hawgood S, Ballard PL. Regulation of messenger RNAs for the hydrophobic surfactant proteins in human lung. J Clin Invest 1989; 83:1191-7. [PMID: 2539393 PMCID: PMC303806 DOI: 10.1172/jci114000] [Citation(s) in RCA: 135] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The pulmonary surfactant proteins SP-B (8,000 D) and SP-C (4,000 D) accelerate surface film formation by surfactant phospholipids. We used cDNA probes to examine regulation of these proteins in human fetal lung. The mRNAs were detectable at 13 wk gestation and increased to approximately 50% (SP-B) and approximately 15% (SP-C) of adult levels at 24 wk. The mRNAs were detected only in lung of 11 dog tissues examined. When human fetal lung was cultured as explants without hormones, SP-B mRNA increased and SP-C mRNA decreased. Exposure for 48 h to glucocorticoids, but not other steroids, increased both SP-B mRNA (approximately 4-fold) and SP-C mRNA (approximately 30-fold) vs. controls. Half-maximal stimulation occurred with 1 nM dexamethasone and 300 nM cortisol for SP-B mRNA and at three- to fivefold higher concentrations for SP-C mRNA. Both stimulation and its reversal on removal of hormone were more rapid for SP-B than for SP-C. Terbutaline and forskolin increased SP-B mRNA but not SP-C mRNA. Levels of both mRNAs were much higher in type II cells than fibroblasts prepared from explants. Thus, the genes for SP-B and SP-C are expressed in vivo before synthesis of both SP-A (28,000-36,000 D) and surfactant lipids. Glucocorticoid induction of SP-B and SP-C mRNAs in type II cells appears to be receptor mediated but may involve different mechanisms.
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Affiliation(s)
- H G Liley
- Department of Pediatrics, University of California, San Francisco 94143
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23
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Horowitz AL, Kaplan RD, Grewe G, White RT, Salberg LM. The ovoid lesion: a new MR observation in patients with multiple sclerosis. AJNR Am J Neuroradiol 1989; 10:303-5. [PMID: 2494849 PMCID: PMC8331393] [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] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
We investigated the frequency of oval-shaped, high-signal-intensity lesions oriented perpendicular to the anteroposterior axis of the brain on abnormal, axial T2-weighted MR brain scans in 59 patients with clinically documented multiple sclerosis. This finding, not heretofore described in patients with multiple sclerosis, was observed in 86% of patients, and correlates with the neuropathologic description of demyelination in multiple sclerosis.
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Affiliation(s)
- A L Horowitz
- Department of Magnetic Resonance Imaging, Resurrection Hospital, Chicago, IL
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24
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Liley HG, White RT, Benson BJ, Ballard PL. Glucocorticoids both stimulate and inhibit production of pulmonary surfactant protein A in fetal human lung. Proc Natl Acad Sci U S A 1988; 85:9096-100. [PMID: 3194412 PMCID: PMC282670 DOI: 10.1073/pnas.85.23.9096] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Pulmonary surfactant is a mixture of phospholipids and proteins which stabilizes lung alveoli and prevents respiratory failure. The surfactant-associated protein of Mr = 28,000-36,000 (SP-A) influences the structure, function (film formation), and metabolism of surfactant. We have characterized glucocorticoid regulation of SP-A and SP-A mRNA in explants of fetal human lung. The time course of response to dexamethasone was biphasic, with early stimulation and later inhibition of SP-A accumulation. Maximal induction of SP-A occurred with 3-10 nM dexamethasone and approximately 300 nM cortisol for 72 hr, and stimulation diminished at higher concentrations. SP-A mRNA accumulation was maximally stimulated at 24-48 hr of exposure to dexamethasone (10 nM) and was generally inhibited by 4-6 days. Stimulation was also observed with cortisone and corticosterone but not with sex steroids, suggesting a receptor-mediated process. When explants were exposed to cortisol for only 24 hr, SP-A content was transiently increased above the level in continuously treated tissue and subsequently was similar to control. The content of SP-A and its mRNA was also increased by dibromo-cAMP, terbutaline, and forskolin, and effects were approximately additive with those of dexamethasone. However, elevated in tracellular cAMP did not alter the biphasic time course or dose-response patterns of dexamethasone. We propose that glucocorticoids have both stimulatory and inhibitory effects on SP-A gene expression. This biphasic regulation is not consistent with generalized toxic effects, product-feedback inhibition, or receptor down-regulation, and it appears to be specific for SP-A among the various surfactant components.
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Affiliation(s)
- H G Liley
- Department of Pediatrics, University of California, San Francisco 94143
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25
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Affiliation(s)
- R T White
- District Department of Community Medicine, Oxford
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26
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Warr RG, Hawgood S, Buckley DI, Crisp TM, Schilling J, Benson BJ, Ballard PL, Clements JA, White RT. Low molecular weight human pulmonary surfactant protein (SP5): isolation, characterization, and cDNA and amino acid sequences. Proc Natl Acad Sci U S A 1987; 84:7915-9. [PMID: 3479771 PMCID: PMC299446 DOI: 10.1073/pnas.84.22.7915] [Citation(s) in RCA: 126] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Pulmonary surfactant is a lipid-protein complex that promotes alveolar stability by lowering the surface tension at the air-fluid interface in the peripheral air spaces. A group of hydrophobic surfactant-associated proteins has been shown to be essential for rapid surface film formation by surfactant phospholipids. We have purified a hydrophobic surfactant protein of approximately 5 kDa that we term SP5 from bronchopulmonary lavage fluid from a patient with alveolar proteinosis and shown that it promotes rapid surface film formation by simple mixtures of phospholipids. We have derived the full amino acid sequence of human SP5 from the nucleotide sequence of cDNAs identified with oligonucleotide probes based on the NH2-terminal sequence of SP5. SP5 isolated from surfactant is a fragment of a much larger precursor protein (21 kDa). The precursor contains an extremely hydrophobic region of 34 amino acids that comprises most of the mature SP5. This hydrophobicity explains the unusual solubility characteristics of SP5 and the fact that it is lipid-associated when isolated from lung.
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Affiliation(s)
- R G Warr
- California Biotechnology, Mountain View 94043
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27
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Haagsman HP, Hawgood S, Sargeant T, Buckley D, White RT, Drickamer K, Benson BJ. The major lung surfactant protein, SP 28-36, is a calcium-dependent, carbohydrate-binding protein. J Biol Chem 1987; 262:13877-80. [PMID: 2820982] [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] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
SP 28-36, a major protein of pulmonary surfactant, has striking amino acid sequence homology with soluble mannose-binding proteins isolated from rat liver and contains residues common to the carbohydrate-binding domains of other mammalian lectins. We have used carbohydrate-affinity chromatography to investigate carbohydrate-binding properties of SP 28-36 isolated from canine and human (alveolar proteinosis patients) lung lavage. SP 28-36 binds to immobilized D-mannose, L-fucose, D-galactose, and D-glucose. The protein binds only weakly to N-acetyl-D-galactosamine and N acetyl-D-glucosamine. Binding is Ca2+-dependent. The threshold Ca2+ concentration is 0.6 mM and maximal binding occurs with 1 mM Ca2+. Bound protein is quantitatively recovered by elution with 2 mM EDTA. Ba2+, Sr2+, and Mn2+, but not Mg2+, can substitute for Ca2+. Unlike some other mammalian lectins, SP 28-36 binds to carbohydrate at pH 5.0. Recombinant human SP 28-36 isolated from the media of Chinese hamster ovary cells, transfected with a DNA construct encoding SP 28-36, has similar carbohydrate-binding activity to the native proteins. Mannose affinity chromatography of the culture medium of Chinese hamster ovary cells results in an efficient purification of the secreted recombinant human SP 28-36.
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Affiliation(s)
- H P Haagsman
- Cardiovascular Research Institute, University of California, San Francisco 94143
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28
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Fisher JH, Kao FT, Jones C, White RT, Benson BJ, Mason RJ. The coding sequence for the 32,000-dalton pulmonary surfactant-associated protein A is located on chromosome 10 and identifies two separate restriction-fragment-length polymorphisms. Am J Hum Genet 1987; 40:503-11. [PMID: 2884868 PMCID: PMC1684155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The primary protein component of human pulmonary surfactant is a 32,000-dalton glycoprotein called surfactant-associated protein A. This protein is important for normal lung function, and its expression is developmentally regulated. Using a mapping panel of somatic-cell hybrids, we have localized the coding sequence for pulmonary surfactant-associated protein A to chromosome 10. Additionally, this sequence identifies two separate MspI restriction-fragment-length polymorphisms. Since there is a relative lack of polymorphic markers for chromosome 10, this sequence may be useful in linkage analysis.
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29
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Liley HG, Hawgood S, Wellenstein GA, Benson B, White RT, Ballard PL. Surfactant protein of molecular weight 28,000-36,000 in cultured human fetal lung: cellular localization and effect of dexamethasone. Mol Endocrinol 1987; 1:205-15. [PMID: 3331167 DOI: 10.1210/mend-1-3-205] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
We have examined the effect of explant culture and hormones on the major surfactant associated protein of Mr 28,000-36,000 (SP 28-36) in human fetal lung. Explants of 16- to 23-week gestation lung were maintained for up to 5 days in culture. Polyclonal antibodies raised to SP 28-36 purified from alveolar proteinosis lung lavage were used in immunofluorescence experiments (n = 11). There was no specific fluorescence seen in frozen sections of preculture tissue. In explants cultured without serum or hormones, fluorescence was seen in most epithelial cells lining potential airspaces. In cultures treated with 10 nM dexamethasone and 2 nM T3 much brighter fluorescence was seen in virtually all epithelial cells. Immunofluorescence studies on cell monolayers prepared from explants confirmed that SP 28-36 is found in the cytoplasm of type II cells but not in fibroblasts. The pattern of fluorescence was consistent with the presence of SP 28-36 on rough endoplasmic reticulum. SP 28-36 mRNA was measured in isolated cell populations using a 32P-labeled cDNA probe. mRNA levels were manyfold higher in type II cell preparations (purity 78-92%) than in fibroblasts (purity 81-97%). A competitive enzyme linked assay was developed to quantify SP 28-36. The SP 28-36 content of five lungs before culture (17-23 weeks) was less than 0.02 microgram/mg DNA. During explant culture without hormones the SP 28-36 content increased exponentially. Exposure to dexamethasone accelerated the increase in SP 28-36 content. T3, alone or in the presence of dexamethasone, did not influence SP 28-36 content. We conclude that SP 28-36 content is very low in human fetal lung before 24 weeks gestation. Explant culture and treatment with dexamethasone synchronize development of type II cells from epithelial precursors, and induce synthesis of SP 28-36 in type II cells. These findings provide evidence of concomitant regulation by glucocorticoids of the phospholipid synthetic enzymes and the major protein of pulmonary surfactant.
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Affiliation(s)
- H G Liley
- Department of Pediatrics, University of California, San Francisco 94143
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30
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Hawgood S, Benson BJ, Schilling J, Damm D, Clements JA, White RT. Nucleotide and amino acid sequences of pulmonary surfactant protein SP 18 and evidence for cooperation between SP 18 and SP 28-36 in surfactant lipid adsorption. Proc Natl Acad Sci U S A 1987; 84:66-70. [PMID: 3467361 PMCID: PMC304142 DOI: 10.1073/pnas.84.1.66] [Citation(s) in RCA: 291] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Pulmonary surfactant is a lipid-rich material that promotes alveolar stability by lowering the surface tension at the air-fluid interface in the peripheral air spaces. The turnover of surfactant phospholipids in the alveolar space is fast, and several lines of evidence suggest there is rapid formation and replenishment of the phospholipid surface film during normal respiration. Specific proteins may regulate these dynamic surface properties. The predominant surfactant protein is a well-characterized, lipid-associated glycoprotein, SP 28-36 (28-36 kDa). A second group of very hydrophobic proteins has recently been shown to affect the surface activity of surfactant phospholipids. We have isolated this group of hydrophobic proteins, herein called SP 5-18 (5-18 kDa), from canine surfactant and have shown by NH2-terminal sequence analysis that at least two proteins, SP 5-8 and SP 18, are present in this group. We have derived the full amino acid sequence of SP 18 from the nucleotide sequence of the cDNAs identified with oligonucleotide probes that were based on the NH2-terminal amino acids of SP 18. The protein isolated from extracellular surfactant appears to be a fragment of a much larger precursor protein (40 kDa). The amino acid sequence of SP 18 is markedly hydrophobic and contains two possible bilayer-spanning domains. We have shown that SP 18 and the glycoprotein SP 28-36 have a cooperative, calcium-dependent action in promoting the formation of phospholipid surface films.
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31
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Dale B, Brown R, Miller J, White RT, Air GM, Cordell B. Nucleotide and deduced amino acid sequence of the influenza neuraminidase genes of two equine serotypes. Virology 1986; 155:460-8. [PMID: 3788060 DOI: 10.1016/0042-6822(86)90207-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Equine influenza is caused by two serotypes of type A influenza virus, EIV-A1 and EIV-A2. The complete nucleotide sequence of the neuraminidase (NA) genes of both the A1 (N7 subtype) and A2 (N8 subtype) serotype has been determined following cloning of full-length viral NA cDNAs into pBR322. Analysis of the deduced amino acid sequences reveals that the N7 and N8 genes share expected extensive homologies with the previously sequenced N1, N2, and N9 NA subtypes. These homologies include conservation of basic NA gene and protein structure, cysteine residues, potential glycosylation sites, and residues known to reside in the enzyme active site of the NA molecule. Additionally, the N1 and N8 molecules and the N7 and N9 molecules are more related by total amino acid homology than any other combination of two subtypes. The area of homology in both cases is particularly strong in the region of residues 100-205, an area roughly corresponding to the amino terminal one-third of the "head" of the NA protein.
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32
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Ballard PL, Hawgood S, Liley H, Wellenstein G, Gonzales LW, Benson B, Cordell B, White RT. Regulation of pulmonary surfactant apoprotein SP 28-36 gene in fetal human lung. Proc Natl Acad Sci U S A 1986; 83:9527-31. [PMID: 3467323 PMCID: PMC387173 DOI: 10.1073/pnas.83.24.9527] [Citation(s) in RCA: 74] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Pulmonary surfactant stabilizes lung alveoli, preventing respiratory failure and hyaline membrane disease in premature infants. In addition to lipids, surfactant contains apoproteins that are thought to be critical for normal surfactant function. We have examined the ontogeny and regulation of the major surfactant-associated protein of molecular mass 28-36 kDa (SP 28-36) in human fetal lung. SP 28-36 was not detected in tissue from second trimester abortuses by either immunoblot analysis or enzyme-linked immunosorbent assay (less than 0.02 microgram per mg of DNA). Levels of mRNA for SP 28-36, assayed by cDNA hybridization, were low or undetectable in all preculture specimens. The concentration of saturated phosphatidylcholine in lung tissue was 30% of the adult value with no apparent increase between 15 and 24 weeks gestation. SP 28-36 content increased during explant culture in the absence of serum and hormones, exceeding adult levels (3.2 +/- 1.0 micrograms per mg of DNA) after 5 days. In cultures treated with triiodothyronine (2 nM) and dexamethasone (10 nM), hormones that regulate phosphatidylcholine synthesis, the increase in SP 28-36 was accelerated (treated/control ratio was 7.1 and 3.4 at 3 and 5 days, respectively). Levels of mRNA for SP 28-36 also increased during culture and were stimulated by hormones (treated/control = 8.6 and 1.9 at 3 and 5 days, respectively). SP 28-36 and its mRNA increased similarly in the presence of dexamethasone alone, whereas triiodothyronine alone had no apparent effect. The molecular weight and charge pattern was similar for SP 28-36 of adult and cultured fetal tissue. These findings indicate that expression of the SP 28-36 gene is low during the second trimester, increases during explant culture, and is accelerated by glucocorticoid treatment.
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33
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Benson B, Hawgood S, Schilling J, Clements J, Damm D, Cordell B, White RT. Structure of canine pulmonary surfactant apoprotein: cDNA and complete amino acid sequence. Proc Natl Acad Sci U S A 1985; 82:6379-83. [PMID: 3863100 PMCID: PMC390719 DOI: 10.1073/pnas.82.19.6379] [Citation(s) in RCA: 123] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The apoproteins of pulmonary surfactant (PSAP) are thought to be critical for normal surfactant function. They bind to surfactant phospholipids and enhance their ability to form surface films in vitro. These acidic glycoproteins have monomeric molecular weights of 36,000, 32,000, and 28,000 (PSAP-36, -32, and -28). Each member of this family of proteins has a similar amino acid composition and their differences in electrophoretic mobility are due in part to glycosylation. We have derived the full amino acid sequence of PSAP-32 from the nucleotide sequence of PSAP cDNA. A cDNA library was prepared from canine lung poly(A)+ RNA and screened with oligonucleotide probes that were based on the NH2-terminal amino acids of PSAP-32 determined by Edman degradation. This protein has the striking feature of collagen-like and non-collagen-like sequences in the same polypeptide chain. There are 24 Gly-Xaa-Yaa triplets, where Yaa is often hydroxyproline. These repeats comprise one-third of PSAP near the NH2 terminus. The remaining two-thirds of PSAP is resistant to bacterial collagenase digestion and contains a possible N-glycosylation site near the carboxyl terminus. The NH2-terminal one-third of PSAP-32 probably contains the cysteine involved in interchain disulfide bonds.
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34
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White RT, Damm D, Miller J, Spratt K, Schilling J, Hawgood S, Benson B, Cordell B. Isolation and characterization of the human pulmonary surfactant apoprotein gene. Nature 1985; 317:361-3. [PMID: 2995821 DOI: 10.1038/317361a0] [Citation(s) in RCA: 320] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Pulmonary surfactant is a phospholipid-protein complex which serves to lower the surface tension at the air-liquid interface in the alveoli of the mammalian lung and is essential for normal respiration. Inadequate levels of surfactant at birth, a frequent situation in premature infants, results in respiratory failure. In all species examined, surfactant is composed primarily of dipalmitoylphosphatidylcholine and two major protein species of relative molecular mass (Mr) 32,000 (32K) and 10K (refs 2-5). Reconstitution in vitro of purified 32K pulmonary surfactant apoprotein (PSAP) with synthetic lipids forms a lipoprotein complex that lowers surface tension by spreading to create a thin interfacial film. Here we describe the cloning of the human PSAP gene and complementary DNA, and discuss features of the unusual encoded protein.
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35
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Abstract
A late region deletion mutant of simian virus 40 (dl5) was previously shown to be deficient in the transport of nuclear RNA. This is a splice junction deletion that has lost the 3' end of an RNA leader, an intervening sequence, and the 5' end of the splice acceptor site on the body of the mRNA. In this report, we analyzed the steady-state structure of the untransported nuclear RNA. The 5' ends of this RNA are heterogeneous but contain a prominent 5' end at the normal position (nucleotide 325) in addition to several other prominent 5' ends not seen in wild-type RNA. The 3' end of this RNA does not occur at the usual position (nucleotide 2674) of polyadenylation; instead, this RNA is non-polyadenylated, with the 3' end occurring either downstream or upstream of the normal position.
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36
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Abstract
Eight young men (group A) underwent 5 h of quiet sitting, preceded by 30 min of recumbency, 20 min of standing, and 20 s of walking, and five other young men (group B) underwent 70 min of sitting, preceded by recumbency only, to determine the effects of prolonged sitting and previous posture on hemodynamic responses (measured by impedance plethysmography). Group A showed more calf blood pooling and a decrease in thigh blood flow during sitting in comparison with the control group, but after 1 h of sitting hemodynamic responses of the two groups were similar. Sitting for 5 h (1st vs. 5th h) resulted in an increase in calf venous pooling (17%) and a decrease in calf BF (13%), a reduction in gravitational pooling in the thigh (corresponding to increased pooling in the calf), increases in diastolic and mean arterial pressures (6 and 7.3 mmHg, respectively), and minor changes in heart rate, stroke volume, and cardiac output. The results show that it is necessary to sit for 1 h before hemodynamic responses can be assessed in this position, regardless of the posture maintained previously. The main effect of prolonged sitting is pooling in the calf, which is compensated for by an increase in peripheral resistance.
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37
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Shvartz E, Gaume JG, Reibold RC, Glassford EJ, White RT. Effect of the circutone seat on hemodynamic, subjective, and thermal responses to prolonged sitting. Aviat Space Environ Med 1982; 53:795-802. [PMID: 7181812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Eight young men were twice administered--on two different days--a series of hemodynamic (using an impedance plethysmograph), subjective, and skin temperature measurements during 5 h of quite sitting. On one day, a Circutone seat (massage-type seat cushion) was activated for 14 min/h, and on the other day it was not. During the "Circutone off" day, 5 h of sitting resulted in a continuous decrease in calf blood flow and an increase in venous blood pooling in the calf; an increase in blood pressure and a stable cardiac output (4.6 l/min); very low urine output; large increases in skin temperatures at the body areas in contact with the seat (thigh and lower back); and increases in various subjective responses of discomfort. The Curcutone activation resulted in a substantial exchange of the stagnant blood in the calf and thigh; a tendency to increase thigh and calf blood flow; a decrease in venous pooling in the thigh; and less subjective discomfort. The Circutone activation had no effect on skin temperature. The results indicate that the Circutone seat improved seat comfort by improving local circulation, especially in the thigh, which probably accounted for the improved subjective reactions.
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38
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White RT, Berg P, Villarreal LP. Simian virus 40-rabbit beta-globin recombinants lacking late mRNA splice sites express cytoplasmic RNAs with altered structures. J Virol 1982; 42:262-74. [PMID: 6283144 PMCID: PMC256067 DOI: 10.1128/jvi.42.1.262-274.1982] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Deletions were introduced at exon-intron boundaries in the late region of a simian virus 40-beta-globin cDNA recombinant to study the role of splicing in the formation of simian virus 40 late cytoplasmic RNAs. The recombinant was used as a wild type because it allowed characterization of mutant RNAs expressed from defective genomes in the presence of comparable RNAs contributed by the coinfecting helper virus. Removal of a 17-base pair segment at map position 0.76, which included a portion of the leader sequence implicated in the splicing of the major 16S mRNA, prevented expression of 16S-type mRNA. The same mutant accumulated cytoplasmic 19S-type mRNA, but the assortment of the 5' ends of these mRNAs differed from the assortment of the wild-type counterparts. Another mutant that lacks nucleotide sequences implicated in the splicing of the major 16S mRNA and one of the principal 19S-type RNAs accumulated a 16S-type mRNA with a previously undetected leader splice, and assortment of 19S mRNAs with new or normally underrepresented splices, and even a species of unspliced cytoplasmic 19S mRNA.
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Shvartz E, Reibold RC, White RT, Gaume JG. Hemodynamic responses in orthostasis following 5 hours of sitting. Aviat Space Environ Med 1982; 53:226-31. [PMID: 7187215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Six young men were administered an orthostatic test, 20 min of quiet standing before and after 5 h of quiet sitting, to determine the effect of sitting fatigue on orthostatic responses. Hemodynamic responses were recorded with an impedance plethysmograph. During the 5 h sitting period, there was a 15.6% decrease in calf blood flow, a 19.4% increase in venous pooling in the calf, and an increase in blood pressure. A comparison between the two standing tests showed increases in blood pressure and in total peripheral resistance, decreases in heart rate (7 beats/min), cardiac output (12.7%) and calf blood flow (18.5%), and 70% increase in calf venous pooling after sitting. The results show that prolonged sitting constitutes a mild orthostatic stress where an increase in venous pooling is compensated by an increase in blood pressure. When this is followed by standing, insufficient compensations are made to the large amounts of pooling resulting from both postures. Despite the maintenance of a stable blood pressure (same as at the end of the sitting period) there is an insufficient increase in total peripheral resistance and heart rate resulting in a relatively low cardiac output. Thus, prolonged sitting constitutes a liability for subsequent performance in an upright position unless methods to minimize venous pooling are employed.
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Girling PD, White RT. The use of official sub-national population projections in England: Phase I, central government departments and public utilities. Social Science Information Studies 1981; 1:297-306. [PMID: 12265273 DOI: 10.1016/0143-6236(81)90042-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
"The use made of the official population projections and the derivative household and labour supply projections has been investigated recently in England through a survey of user and potential user organizations. In view of the rather complex arrangements for producing the official projections, the paper begins by providing a summary of what projections are prepared and by whom.... The main part...presents an analysis of the results of the survey...concerned with who uses the projections, the factors influencing the use and value of projections and the demands for an extension of the current service."
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Abstract
We have analyzed the structure of the late cytoplasmic RNAs made after infection with wild-type simian virus 40 and a set of viable mutants, four of which have deletions and one an insertion within the nucleotide sequence specifying the leader segment of the 16S and 19S mRNA's. The principal findings are: (i) simian virus 40 16S and 19S mRNA's made during infections with wild-type virnds and possibly in the nucleotide sequence comprising the "leader" segments. (II) "Spliced" 16S and 19S mRNA's are made during infections with each of the mutants although, in some cases, the ratio of 19S to 16S mRNA species is reduced. (iii) The deletion or insertion of nucleotides within the DNA segment defined by map position 0.70 to 0.75 causes striking alterations in the types of leader structures in the late mRNAs. (iv) Many of the late RNA leader segments produced after infection with the mutants appear to be multiply spliced, i.e., instead of the major 200- to 205-nucleotide-long leader segment present in wild-type 16S mRNA, the RNAs produced by several of the deletion mutants have leaders with whort discontiguous segments.
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White RT. Development of surgery for obesity/mechanism of action. Med J Aust 1976; 2:698. [PMID: 1012119 DOI: 10.5694/j.1326-5377.1976.tb130443.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Williams S, White RT. Letter: Psychosurgery and society. Med J Aust 1975; 1:577. [PMID: 1143150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Abstract
Amygdaloidotomy was performed bilaterally on 15 and unilaterally on three patients exhibiting severe aggressive or self-mutilating behaviour. Nine subjects (50%) were improved a year after operation; improvement was maintained in seven (39%) for periods ranging from 27 months to nearly six years. Four non-epileptic cases had convulsions during the period of review; one of them has a persistent mild hemiparesis dating from the postoperative period. There was a tendency for epileptics to respond better than non-epileptics and for mentally retarded patients to respond poorly, but none of the differences was statistically significant.
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White RT. Psychosurgery reconsidered: comment 1. Med J Aust 1974; 1:70. [PMID: 4816058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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