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Tzompa-Sosa ZA, Henderson BH, Keller CA, Travis K, Mahieu E, Franco B, Estes M, Helmig D, Fried A, Richter D, Weibring P, Walega J, Blake DR, Hannigan JW, Ortega I, Conway S, Strong K, Fischer EV. Atmospheric implications of large C 2-C 5 alkane emissions from the U.S. oil and gas industry. J Geophys Res Atmos 2019; 124:1148-1169. [PMID: 32832312 PMCID: PMC7433792 DOI: 10.1029/2018jd028955] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 12/18/2018] [Indexed: 06/10/2023]
Abstract
Emissions of C2-C5 alkanes from the U.S. oil and gas sector have changed rapidly over the last decade. We use a nested GEOS-Chem simulation driven by updated 2011NEI emissions with aircraft, surface and column observations to 1) examine spatial patterns in the emissions and observed atmospheric abundances of C2-C5 alkanes over the U.S., and 2) estimate the contribution of emissions from the U.S. oil and gas industry to these patterns. The oil and gas sector in the updated 2011NEI contributes over 80% of the total U.S. emissions of ethane (C2H6) and propane (C3H8), and emissions of these species are largest in the central U.S. Observed mixing ratios of C2-C5 alkanes show enhancements over the central U.S. below 2 km. A nested GEOS-Chem simulation underpredicts observed C3H8 mixing ratios in the boundary layer over several U.S. regions and the relative underprediction is not consistent, suggesting C3H8 emissions should receive more attention moving forward. Our decision to consider only C4-C5 alkane emissions as a single lumped species produces a geographic distribution similar to observations. Due to the increasing importance of oil and gas emissions in the U.S., we recommend continued support of existing long-term measurements of C2-C5 alkanes. We suggest additional monitoring of C2-C5 alkanes downwind of northeastern Colorado, Wyoming and western North Dakota to capture changes in these regions. The atmospheric chemistry modeling community should also evaluate whether chemical mechanisms that lump larger alkanes are sufficient to understand air quality issues in regions with large emissions of these species.
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Affiliation(s)
- Z A Tzompa-Sosa
- Department of Atmospheric Science, Colorado State University, Colorado, USA
| | - B H Henderson
- Air Quality Modeling Group, Office of Air Quality Planning and Standards, US Environmental Protection Agency, USA
| | - C A Keller
- Universities Space Research Association / GESTAR, National Aeronautics and Space Administration, Maryland, USA
- Global Modeling and Assimilation Office, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
| | - K Travis
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - E Mahieu
- Institut d'Astrophysique et de Géophysique, Université de Liège, Quartier Agora, Liège, Belgium
| | - B Franco
- Université libre de Bruxelles (ULB), Atmospheric Spectroscopy, Service de Chimie Quantique et Photophysique, Brussels, Belgium
| | - M Estes
- Air Modeling and Data Analysis Section, Texas Commission on Environmental Quality, Texas, USA
| | - D Helmig
- Institute of Arctic and Alpine Research, University of Colorado Boulder, Colorado, USA
| | - A Fried
- Institute of Arctic and Alpine Research, University of Colorado Boulder, Colorado, USA
| | - D Richter
- Institute of Arctic and Alpine Research, University of Colorado Boulder, Colorado, USA
| | - P Weibring
- Institute of Arctic and Alpine Research, University of Colorado Boulder, Colorado, USA
| | - J Walega
- Institute of Arctic and Alpine Research, University of Colorado Boulder, Colorado, USA
| | - D R Blake
- Department of Chemistry, University of California, Irvine, California, USA
| | - J W Hannigan
- National Center for Atmospheric Research, Boulder, Colorado, USA
| | - I Ortega
- National Center for Atmospheric Research, Boulder, Colorado, USA
| | - S Conway
- Department of Physics, University of Toronto, Toronto, Ontario, Canada
| | - K Strong
- Department of Physics, University of Toronto, Toronto, Ontario, Canada
| | - E V Fischer
- Department of Atmospheric Science, Colorado State University, Colorado, USA
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Predoi-Cross A, Hnatovsky C, Strong K, Drummond J, Chris Benner D. Corrigendum to “Temperature dependence of self- and N2-broadeningand pressure-induced shifts in the 3 ← 0 band of CO” [J. Mol. Struct. 695–696 (2004) 269–286]. J Mol Struct 2015. [DOI: 10.1016/j.molstruc.2015.07.009] [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]
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Douzgou S, Clayton-Smith J, Gardner S, Day R, Griffiths P, Strong K. Dysmorphology at a distance: results of a web-based diagnostic service. Eur J Hum Genet 2013; 22:327-32. [PMID: 23838594 DOI: 10.1038/ejhg.2013.137] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Revised: 04/17/2013] [Accepted: 05/27/2013] [Indexed: 02/01/2023] Open
Abstract
In 2007, the DYSCERNE pilot project funded by the European Commission Public Health Executive Agency (EU DG Sanco) aimed at setting up a network of expertise for patients with rare dysmorphic disorders. As part of DYSCERNE, a Dysmorphology Diagnostic System (DDS) was set up to enable clinicians throughout the EU to submit cases electronically for diagnosis using a secure, web-based interface, hosted at specified access points (Submitting nodes), in 26 different European countries. We report the outcome of this service for 200 cases submitted consecutively between January 2010 and 2012. Each case was reviewed by an average of five expert reviewers. An average of three possible syndromic diagnoses was suggested per case. In 22.5% of the cases, a consensus clinical diagnosis was reached. Genetic testing was suggested in 70.5% of the cases, whereas other laboratory investigations and diagnostic imaging were recommended in 35.5 and 26% of the cases, respectively. Further specialized opinions were suggested in 23.5% of the cases. Overall, a total of 181 very rare or extremely rare genetic syndromes were considered in the differential diagnosis of the 200 cases. In two cases, the reviewers suggested that the findings represented a new syndrome, and in one of these syndromes the underlying genetic cause was subsequently identified. Other benefits of the submission process included the possibility of directing the case submitters to specific centres for diagnostic testing or participation in research and educational benefit derived for both case submitters and reviewers.
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Jones A, Qin G, Strong K, Walker KA, McLinden CA, Toohey M, Kerzenmacher T, Bernath PF, Boone CD. A global inventory of stratospheric NOyfrom ACE-FTS. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2010jd015465] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Toohey M, Strong K, Bernath PF, Boone CD, Walker KA, Jonsson AI, Shepherd TG. Validating the reported random errors of ACE-FTS measurements. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2010jd014185] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Matthews N, Kurosawa K, Strong K. Hastening orientation sensitivity. J Vis 2010. [DOI: 10.1167/6.6.157] [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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Hocking WK, Carey-Smith T, Tarasick DW, Argall PS, Strong K, Rochon Y, Zawadzki I, Taylor PA. Detection of stratospheric ozone intrusions by windprofiler radars. Nature 2007; 450:281-4. [DOI: 10.1038/nature06312] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2007] [Accepted: 09/24/2007] [Indexed: 11/09/2022]
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Farahani E, Fast H, Mittermeier RL, Makino Y, Strong K, McLandress C, Shepherd TG, Chipperfield MP, Hannigan JW, Coffey MT, Mikuteit S, Hase F, Blumenstock T, Raffalski U. Nitric acid measurements at Eureka obtained in winter 2001–2002 using solar and lunar Fourier transform infrared absorption spectroscopy: Comparisons with observations at Thule and Kiruna and with results from three-dimensional models. ACTA ACUST UNITED AC 2007. [DOI: 10.1029/2006jd007096] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Waterland R, Hurley M, Misner J, Wallington T, Melo S, Strong K, Dumoulin R, Castera L, Stock N, Mabury S. Gas phase UV and IR absorption spectra of CF3CH2CH2OH and F(CF2CF2)xCH2CH2OH (x=2, 3, 4). J Fluor Chem 2005. [DOI: 10.1016/j.jfluchem.2005.06.010] [Citation(s) in RCA: 15] [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: 11/26/2022]
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Strong K, Wald N, Miller A, Alwan A. Current concepts in screening for noncommunicable disease: World Health Organization Consultation Group Report on methodology of noncommunicable disease screening. J Med Screen 2005; 12:12-9. [PMID: 15825234 DOI: 10.1258/0969141053279086] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Screening people for serious diseases is receiving increasing attention as studies demonstrates the potential benefits of early detection and early intervention in preventing morbidity and mortality. Screening tests are available for some of the most important noncommunicable diseases, including cardiovascular disease, type 2 diabetes and several site-specific cancers. However, screening guidelines for cardiovascular disease, cancers and diabetes vary within and between countries because many national and international organizations are developing their own guidelines. There is a need to address the issue of screening for disease, with an emphasis on providing accurate and practical information relevant to all countries. This report arose from a Consultation Group meeting held at WHO headquarters in Geneva. It presents an examination of the principles of screening with an emphasis on noncommunicable disease prevention and control policy.
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Abstract
OBJECTIVE The overriding objective of this paper is to outline the steps involved in refining a structural model to explain differences in dieting status. METHODS Cross-sectional data (representing the responses of 1,644 teenage girls) derive from the preliminary testing in a 3-year longitudinal study. A battery of measures assessed social influence, vulnerability (to conformity) disposition, protective (social coping) skills, and aspects of positive familial context as core components in a model proposed to account for the initiation of dieting. Path analyses were used to establish the predictive ability of those separate components and their interrelationships in accounting for differences in dieting status. RESULTS Several components of the model were found to be important predictors of dieting status. The model incorporates significant direct, indirect (or mediated), and moderating relationships. Taking all variables into account, the strongest prediction of dieting status was from peer competitiveness, using a new scale developed specifically for this study. CONCLUSION Systematic analyses are crucial for the refinement of models to be used in large-scale multivariate studies. In the short term, the model investigated in this study has been shown to be useful in accounting for cross-sectional differences in dieting status. The refined model will be most powerfully employed in large-scale time-extended studies of the initiation of dieting to lose weight.
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Affiliation(s)
- G Huon
- School of Psychology, University of New South Wales, Sydney, Australia
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Affiliation(s)
- K Strong
- Australian Institute of Health and Welfare, Canberra, Australian Capital Territory, Australia.
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O'Riordan JM, Conroy A, Nourse C, Yap PL, McDonald GS, Kaminski G, Leong K, Lawlor E, Davoren A, Strong K, Davidson F, Lloyd A, Power J. Risk of hepatitis C infection in neonates transfused with blood from donors infected with hepatitis C. Transfus Med 1998; 8:303-8. [PMID: 9881424 DOI: 10.1046/j.1365-3148.1998.00172.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [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: 11/20/2022]
Abstract
This look-back study was undertaken to identify newborn infants who had been infected with the hepatitis C virus (HCV) as a result of transfusions received before the introduction of routine screening in 1991 and to determine the transmission rates and persistence of transfusion-transmitted HCV infection acquired in the neonatal period. A total of 24 infants, transfused between 1980 and 1991, were identified as having received potentially infected blood from 11 blood donors. Ten of the donors had been administered batches of anti-D in 1977 known to have transmitted HCV genotype 1b infection. HCV RNA was detected in five of these donors when tested in 1994-95; the past donations of five of the donors, who had received anti-D immunoglobulin and had serological evidence of previous HCV infection but who were PCR negative when tested in 1994-95, were considered of lower risk. The source and time of acquisition of HCV infection for the one remaining donor in the study was not determined. Twenty-one (88%) of the 24 children were living at time of lookback. The median age at transfusion was 12 days. The median age at time of testing was 6.3 years. One child, who tested negative, was excluded from further analysis of HCV transmission, due to incomplete transfusion records. Overall, 12 of 20 (60%) children tested were positive for anti-HCV and seven (35%) were HCV RNA positive. Twelve (71%) of the 17 recipients of viraemic blood were ELISA positive and seven (41%) were PCR positive. Resolved HCV infection, as determined by ELISA pos, RIBA pos or indeterminate and PCR negativity, occurred in five of 12 (42%). In many instances there was more than one recipient per HCV infected donation. All of the reported children are clinically asymptomatic. However, the duration of HCV infection is relatively short and there is evidence of a degree of hepatitis in five of the seven children who are HCV RNA positive as judged by mildly elevated transaminase levels. The three who have undergone liver biopsy show mild hepatitis. The lower rates of persistence of HCV infection in this study may be due to the young age at exposure or to the source of infection which for all but one of the children was linked to one HCV genotype from female donors. Sharing of units of blood among multiple infants should be discouraged.
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Strong K, de Looper M, Magnus P. Asthma mortality in Australia, 1980-1996. AUST HEALTH REV 1997; 21:255-63. [PMID: 10185690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Affiliation(s)
- K Strong
- Population Health Unit, Australian Institute of Health and Welfare, Canberra ACT
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Abstract
Analysis of mortality, hospital separations and self-reported health indicators by country of birth group has confirmed that overseas-born populations are generally in better health than their Australian-born contemporaries. The better health of the overseas-born may be reflected in both the willingness and eligibility of individuals to emigrate. Overseas-born individuals were placed into one of four groups according to place of birth. These included the United Kingdom and Ireland, Other Europe, Asia and Other. All population groups reported lower mortality and hospitalisation rates for all causes of disease combined. The Asian-born population had the lowest mortality rates with 38% less mortality for males and 30% less for females. Hospitalisation rates were also lower for the Asian-born, with males and females having 46% and 37% fewer hospital separations compared to the Australian-born population. However, diabetes mortality was greater for males and females from Other Europe, Asia and Other regions. Both males and females from the United Kingdom and Ireland group showed increased mortality from lung cancer. Mortality and hospitalisation for cervical cancer was also significantly higher for Asian-born and Other females. The mortality and hospitalisation data corresponded well with self-reported prevalence of health-related risk factors. For example, self-reported diabetes prevalence was higher for the Other Europe, Asia and Other groups. Asian and Other females reported significantly less use of regular Pap smear tests, reflecting their increased mortality and hospitalisation for cervical cancer. These results support the finding of past studies that the health of migrants is generally better than that of the Australian-born population and reflects a 'healthy migrant' effect.
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Strong K, Johnson TJ, Harris GW. Visible intracavity laser spectroscopy with a step-scan Fourier-transform interferometer. Appl Opt 1997; 36:8533-8540. [PMID: 18264398 DOI: 10.1364/ao.36.008533] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
A Fourier-transform spectrometer has been used in a step-scan mode to make time-resolved measurements of the evolving laser pulse in intracavity laser spectroscopy (ILS) experiments. Spectra of broadband dye laser pulses at approximately 615 nm were recorded at relatively high spectral (0.5-cm(-1)) and temporal (as high as 5-mus) resolution. In the absence of an absorber, the height of the pulse is shown to be proportional to t(g)(0.57) (where t(g) is the generation time) for generation times as high as 500 mus. The system was constructed for feasibility studies of future use at infrared and near-infrared wavelengths where conventional ILS that uses diode arrays would be either expensive or simply not possible. The CH(4) overtone transition at 619.68 nm was used to test the linearity and sensitivity of the system. Comparable performance to conventional ILS systems was demonstrated, as were the advantages of the present system for studies of laser and absorption dynamics.
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Strong K, Westenskow DR, Fine PG, Orr JA. A preliminary laboratory investigation of air embolus detection and grading using an artificial neural network. Int J Clin Monit Comput 1997; 14:103-7. [PMID: 9336735 DOI: 10.1007/bf03356584] [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] [Indexed: 02/05/2023]
Abstract
SUMMARY STATEMENT Processed digitized Doppler signals abstracted from recordings during continuous air infusion in dogs were used to train a neural network to estimate air embolism infusion rates. BACKGROUND Precordial Doppler is a sensitive technique for detecting venous air embolism during anesthesia, but it requires constant attentive listening. Since neural networks are particularly well suited to the task of pattern recognition, we sought to investigate this technology for detection and grading of air embolism. METHODS Air was infused into peripheral veins of four anesthetized dogs at rates of 0.025, 0.05, 0.10, 0.25, 0.50 and 1.0 ml-1.kg-1.min-1 while digital recordings of the precordial Doppler ultrasound signal were collected. The frequency content of the recordings was determined by Fourier analysis. The output of the Fourier transform was the input to a neural network. The network was then trained to estimate the air infusion rate. RESULTS The correlation coefficient between the size of the air embolism and the air infusion rate was greater than r2 = 0.93 for each of the four animals in the study when the network was trained using the data for all four dogs. When the data from a dog was withheld from the training set and used only for testing the correlation coefficients ranged from r2 = 0.75 to r2 = 0.27. For frequencies below 250 Hz, the acoustic energy tended to fall as the air infusion rate increased. The opposite occurred at frequencies above 325 Hz. CONCLUSIONS Neural network processing of the precordial Doppler signal provides a quantitative estimate of the size of an air embolism.
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Affiliation(s)
- K Strong
- Department of Bioengineering, University of Utah Health Science Center, Salt Lake City 84132, USA
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Strong K, Jones RL. Remote measurements of vertical profiles of atmospheric constituents with a UV-visible ranging spectrometer. Appl Opt 1995; 34:6223-6235. [PMID: 21060465 DOI: 10.1364/ao.34.006223] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A study of the feasibility of retrieving vertical profiles of atmospheric constituents with a new UV-visible ranging spectrometer recently described by R. L. Jones [Optical Methods in Atmospheric Chemistry, U. Platt and H. I. Schiff, eds., Proc. Soc. Photo-Opt. Instrum. Eng. 1715, 393 (1992)] is presented. This instrument resembles a lidar, in that pulses of UV-visible radiation are transmitted vertically upward and backscattered to receiving optics. However, the pulse is a broadband source, and the receiving optics includes a two-dimensional CCD array that allows a series of absorption spectra to be recorded, each corresponding to a different altitude. This allows the simultaneous measurement of the vertical profiles of such atmospheric constituents as O(3), H(2)O, and NO(2) in the troposphere and lower stratosphere. Formal retrieval theory has been used to model the retrieval of vertical profiles with this instrument, demonstrating that it should be possible to obtain profiles at accuracies better than 30% and resolution better than 3 km up to altitudes of 12-15 km. The way in which the measurement error, flash-lamp pulse length, CCD recording interval, and mixing-ratio profile each affect the accuracy and the vertical resolution of the retrieved profile has also been investigated.
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Allen LR, Fleming PJS, Thompson JA, Strong K. Effect of Presentation on the Attractiveness and Palatability to Wild Dogs and Other Wildlife of 2 Unpoisoned Wild-Dog Bait Types. Wildl Res 1989. [DOI: 10.1071/wr9890593] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Factory-prepared beef crackle cubes and fresh meat baits are routinely used with the poison 1080 to
prevent or reduce predation by wild dogs, Canis familiaris. Four field trials totalling 674 bait nights
per bait type were conducted in southern Queensland to assess the relative attractiveness and palatability
of the two baits to wild dogs and non-target animals. Buried meat and surface-laid meat baits were also
compared to assess the effect that bait presentation can have on control programme efficiency and
non-target hazard. Fresh meat was found to be significantly more palatable to wild dogs than factory
baits. Factory baits, despite being equally attractive to wild dogs as fresh meat, had significantly more
visits by wild dogs where baits were not eaten. Fresh meat was significantly more attractive and
palatable to non-target species than factory baits. Buried baits were equally attractive and palatable
to wild dogs compared with surface-laid meat baits, yet had greatly reduced non-target bait take.
The significance of the results is discussed with regard to the potential 1080 hazard to birds and reptiles
(which removed 28% and 10% of baits, respectively) and the influence that non-target removal of
baits may have on the efficiency and design of wild-dog control programmes.
Extra keywords: Compound 1080, poison, SEA, sodium fluoroacetate.
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Needleman DH, Strong K, Stemke KA, Brabson JS, Kisic A, Schroepfer GJ. Inhibitors of sterol synthesis. Effect of dietary 5 alpha-cholest-8(14)-en-3 beta-ol-15-one on ACAT activity of jejunal microsomes of the rat. Biochem Biophys Res Commun 1987; 148:920-5. [PMID: 3689403 DOI: 10.1016/s0006-291x(87)80220-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.9] [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: 01/06/2023]
Abstract
Dietary administration (0.1% in a chow diet for 8 days) of 5 alpha-cholest-8(14)-en-3 beta-ol-15-one, a potent inhibitor of sterol biosynthesis with marked hypocholesterolemic action, to rats caused a 77% reduction in the levels of acyl co-enzyme A:cholesterol acyl transferase activity of jejunal microsomes relative to those observed in pair-fed control animals. No differences were observed in mean levels of cholesterol concentration in jejunal microsomes of experimental and pair-fed control animals.
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Affiliation(s)
- D H Needleman
- Department of Biochemistry, Rice University, Houston, TX 77251
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Ponsin G, Strong K, Gotto AM, Sparrow JT, Pownall HJ. In vitro binding of synthetic acylated lipid-associating peptides to high-density lipoproteins: effect of hydrophobicity. Biochemistry 1984; 23:5337-42. [PMID: 6439239 DOI: 10.1021/bi00317a036] [Citation(s) in RCA: 26] [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: 01/20/2023]
Abstract
To measure the effect of hydrophobicity on the binding of model apoproteins to lipoproteins, we synthesized a 15 amino acid lipid-associating peptide (LAP) with acyl chains of various lengths (0-18 carbons) bound to the N-terminal amino acid through a peptide bond. The acylated LAPs preferentially bound to high-density lipoprotein (HDL) and were activators of lecithin:cholesterol acyltransferase. Circular dichroic spectra indicated that the LAP association with phospholipid was accompanied by increased alpha-helical structure. The LAPs self-associated in solution as judged from tryptophan fluorescence analysis. These characteristics, which are comparable to those of apolipoprotein A-I, were strongly dependent upon the acyl chain length of the LAPs. The equilibrium constants (Keq) for the association of LAPs to reassembled HDL were measured by equilibrium dialysis at several temperatures. At 37 degrees C, Keq increased by 3 orders of magnitude as the number of carbon units was increased from 0 to 16; there was a log-linear relationship between Keq and the acyl chain length. The free energy of association (delta Ga) decreased by a constant value for each methylene unit added to the acyl chain (0.35 kcal mol-1), clearly demonstrating a strict hydrophobic effect. This change of delta Ga was enthalpy rather than entropy driven. Our data show that, with all other parameters including putative alpha-helicity, sequence, and molecular weight being constant, the binding of a lipid-associating peptide to lipoprotein is governed by its hydrophobicity.
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Sinden RE, Strong K. An ultrastructural study of the sporogonic development of Plasmodium falciparum in Anopheles gambiae. Trans R Soc Trop Med Hyg 1978; 72:477-91. [PMID: 364785 DOI: 10.1016/0035-9203(78)90167-0] [Citation(s) in RCA: 69] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
This paper describes the fine structure of the sporogonic development of Plasmodium falciparum in its natural vector Anopheles gambiae (Species A) as seen by scanning and transmission electron microscopy. The parasite was derived from naturally infected volunteers and the vector maintained under natural conditions at the MRC Laboratories, Fajara, The Gambia. Sporogonic development of P. falciparum is similar to that described for other Plasmodium spp. There are however greater similarities between P. falciparum and the avian malaria parasites, than those mammalian (primarily rodent) species described to date--particularly with respect to mitochondrial development, crystalloid morphology and nucleolar organization. Nuclear development is similar to that of the murine malaria parasites, but reconstruction of complete mitotic spindles from serial sections suggest the haploid genome of P. falciparum contains 14 chromosomes compared to eight to ten in the murine plasmodia. Sporoblast formation involves a unique process of cleft formation based on the expansion of the cisternal space of the endoplasmic reticulum. Sporozoite budding is almost exclusively confined to these inner membrane surfaces and results in a characteristic sporozoite distribution in the oocyst. High resolution scanning electron microscopy of free sporozoites provides the first surface view of the micropore of Plasmodium.
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Sinden RE, Strong K. An ultrastructural study of the sporogonic development of Plasmodium falciparum in Anopheles gambiae. Trans R Soc Trop Med Hyg 1978. [PMID: 364785 DOI: 10.1016/0035-9203(78)90167-90160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/08/2023] Open
Abstract
This paper describes the fine structure of the sporogonic development of Plasmodium falciparum in its natural vector Anopheles gambiae (Species A) as seen by scanning and transmission electron microscopy. The parasite was derived from naturally infected volunteers and the vector maintained under natural conditions at the MRC Laboratories, Fajara, The Gambia. Sporogonic development of P. falciparum is similar to that described for other Plasmodium spp. There are however greater similarities between P. falciparum and the avian malaria parasites, than those mammalian (primarily rodent) species described to date--particularly with respect to mitochondrial development, crystalloid morphology and nucleolar organization. Nuclear development is similar to that of the murine malaria parasites, but reconstruction of complete mitotic spindles from serial sections suggest the haploid genome of P. falciparum contains 14 chromosomes compared to eight to ten in the murine plasmodia. Sporoblast formation involves a unique process of cleft formation based on the expansion of the cisternal space of the endoplasmic reticulum. Sporozoite budding is almost exclusively confined to these inner membrane surfaces and results in a characteristic sporozoite distribution in the oocyst. High resolution scanning electron microscopy of free sporozoites provides the first surface view of the micropore of Plasmodium.
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