RESEARCH LETTER Influence of respiratory variables on the on-line detection of exhaled trace gases by PTR-MS Background Modern gas analysis techniques permit real time and on-line quantification of multiple volatile trace gases within a single exhalation. However, the influence of various respi- ratory manoeuvres affecting exhalation flow and the kinetics of metabolite release to the gas- phase remain largely unknown. Methods We examined variation in the concentrations of selected trace gases over a range of expiratory flows (50; 100; 250 ml/s) and after 30 second periods of breathold and paced hyper- ventilation. On-line measurement of breath samples from healthy volunteers (n¼10) was performed by proton transfer mass spectrometry. Results Exhaled acetone increased with higher expiratory flow rate (805, 838, 898 ppb, p¼0.02). Levels of methanol (206 vs 179 ppb, p<0.01), acetaldehyde (26 vs 22 ppb, p<0.01), ethanol (410 vs 208 ppb, p¼0.01) and dimethyl sulphide (113 vs 103 ncps, p<0.01) fell significantly following 30s hyperventilation. After 30 second breathold levels of methanol (206 vs 217 ppb, p¼0.02), acetone (805 vs 869 ppb, p<0.01), isoprene (348 vs 390 ppb, p¼0.02) and dimethyl sulphide (113 vs 136 ncps, p¼0.02) increased significantly. Variation in respiratory parameters did not signifi- cantly alters the level of acetonitrile, propanol and butyric acid within the breath of healthy subjects. Conclusions These findings demonstrate that respiratory manoeuvres significantly influence the measured concentration of a number of exhaled VOCs that are of potential importance within the clinical setting. Our results support the adoption of standardised practices for breath gas analysis by on-line and real time mass spectrometry methods. Analysis of volatile trace gases within exhaled breath, for the purpose of non-invasive disease detection and monitoring, is a rapidly emerging field of research. 12 Recent techno- logical developments such as proton transfer reaction‑mass spectrometry (PTR-MS) have allowed on-line and real-time detection of multiple trace gases in breath, leading to novel discoveries in cancer, infectious disease and metabolism. 23 One of the greatest lessons on clinical applicability of breath analysis has been the recognition that multiple physiological vari- ables can influence the quantification of exhaled nitric oxide (NO), necessitating international consensus guidelines for its standardised measurement. 4 There remains however limited experimental evidence defining the impact of confounding factors which may influence the quantification of other exhaled volatile trace gases. 5 Herein we present the finding of a study investigating the influence of respiratory variables on the on-line detection and quantification of a judiciously selected and potentially clini- cally relevant panel of expiratory trace gases. We examined the variation in the concentrations of selected trace gases (methanol, acetaldehyde, ethanol, acetone, isoprene, acetonitrile, propanol, dimethyl sulphide and butyric acid) over a range of expiratory flows (50, 100, 250 ml/s) and after the 30-s periods of breath hold and paced hyperventilation. These volatiles were compared to exhaled NO and carbon dioxide. On-line measurement of breath samples from healthy volunteers (n¼10) was performed by combining PTR-MS (Ionimed Analytik GmbH, Innsbruck, Austria) with the LR2500 multiple-gas analyser (Logan Research Ltd, Rochester, UK). Quantification of trace gases by PTR-MS was achieved by calibration experiments using accurately known gas standards and a purpose built gas calibration unit (Ionimed). (Further details of methodology are provided as supplementary digital content). In contrast to NO, exhibiting an inverse relationship with expiratory flow rate, exhaled acetone increased with higher flows (805 vs 838, 898 ppb, p¼0.02) (figure 1). After a 30-s breath hold, levels of acetone (805 vs 869 ppb, p<0.01), methanol (206 vs 217 ppb, p¼0.02), isoprene (348 vs 390 ppb, p¼0.02) and dimethyl sulphide (113 vs 136 ncps, p¼0.02) increased significantly. Levels of methanol (206 vs 179 ppb, p<0.01), dimethyl sulphide (113 vs 103 ncps, p<0.01), acetaldehyde (26 vs 22 ppb, p<0.01) and ethanol (410 vs 208 ppb, p¼0.01) fell significantly following the 30-s hyperventi- lation (figure 1). Variation in respiratory parameters did not significantly alter the levels of acetonitrile, propanol and butyric acid (table 2 in online supplement). This work constitutes the first concerted attempt to discern the effect of ventilatory variables on breath analysis by an on-line MS- based analytical technique. The principal findings of this study are (i) PTR-MS evidence for the flow dependency of exhaled acetone; (ii) changing minute ventilation can both increase and decrease the concentrations of selected exhaled trace gases; and (iii) concen- trations of certain volatiles were not Figure 1 Influence of respiratory physiological variables on the concentrations of selected trace gases measured within the exhaled breath of healthy volunteers. Trace gas level are presented as the ratio of the difference in breath manoeuvres versus their respective control breath measures at a flow rate of 50 ml/s. Boshier PR, Priest OH, Hanna GB, et al. Thorax (2011). doi:10.1136/thx.2011.161208 1 of 2 PostScript Thorax Online First, published on April 7, 2011 as 10.1136/thx.2011.161208 Copyright Article author (or their employer) 2011. Produced by BMJ Publishing Group Ltd (& BTS) under licence. on June 4, 2020 by guest. Protected by copyright. http://thorax.bmj.com/ Thorax: first published as 10.1136/thx.2011.161208 on 7 April 2011. Downloaded from
significantly altered by respiratory manoeu- vres in healthy volunteers. These preliminary observations may have important implications regarding the stand- ardisation requirement for measuring and reporting the concentrations of exhaled trace gases in the future. Further larger studies both in healthy and diseased subjects are necessary to expand on these observations and to provide mechanistic insights into exchange kinetics of affected volatiles. Such studies may help to further define the exact role of on-line MS technologies in non-inva- sive diagnosis and monitoring pulmonary and systemic diseases. Piers R Boshier, 1 Oliver H Priest, 1 George B Hanna, 1 Nandor Marczin 2,3 1 Department of Surgery and Cancer, Imperial College London, St Mary’s Hospital, London, UK; 2 Department of Surgery and Cancer, Section of Anaesthetics, Pain Medicine and Intensive Care, Imperial College London, Chelsea and Westminster Hospital, London, UK; 3 Department of Anaesthetics, Harefield Hospital, The Royal Brompton and Harefield NHS Foundation Trust, Harefield, Middlesex, UK Correspondence to Dr Nandor Marczin, Department of Surgery and Cancer, Section of Anaesthetics, Pain Medicine and Intensive Care, Imperial College London, Chelsea and Westminster Hospital, London SW10 9NH, UK; n.marczin@imperial.ac.uk < An additional table is published online only. To view this file please visit the journal online (http://thorax.bmj.com). Competing interests None. Ethics approval This study was conducted with the approval of the Riverside Research Ethics Committee (project reference number: 08/H0706/134). Provenance and peer review Not commissioned; externally peer reviewed. Accepted 9 February 2011 Thorax 2011;-:1e2. doi:10.1136/thx.2011.161208 REFERENCES 1. Kharitonov SA, Barnes PJ. Exhaled biomarkers. Chest 2006;130:1541e6. 2. Amann A, Smith D, eds. Breath Analysis for Clinical Diagnosis and Therapeutic Monitoring. Singapore: World Scientific, 2005. 3. Lindinger W, Hansel A, Jordan A. On-line monitoring of volatile organic compounds at pptv levels by means of proton-transfer-reaction mass spectrometry (PTR-MS)-medical applications, food control and environmental research. Int J Mass Spectrom 1998;173:191e241. 4. American Thoracic Society; European Respiratory Society. ATS/ERS recommendations for standardized procedures for the online and offline measurement of exhaled lower respiratory nitric oxide and nasal nitric oxide, 2005. Am J Respir Crit Care Med 2005;171:912e30. 5. Larstad MA, Toren K, Bake B, et al. Determination of ethane, pentane and isoprene in exhaled air: effects of breath-holding, flow rate and purified air. Acta Physiol (Oxf) 2007;189:87e98. 2 of 2 Boshier PR, Priest OH, Hanna GB, et al. Thorax (2011). doi:10.1136/thx.2011.161208 PostScript on June 4, 2020 by guest. Protected by copyright. http://thorax.bmj.com/ Thorax: first published as 10.1136/thx.2011.161208 on 7 April 2011. Downloaded from
Thorax Online First, published on April 7, 2011 as 10.1136/thx.2011.161208
PostScript
RESEARCH LETTER
Background Modern gas analysis techniques permit real time and on-line quantification of
multiple volatile trace gases within a single exhalation. However, the influence of various respiratory manoeuvres affecting exhalation flow and the kinetics of metabolite release to the gasphase remain largely unknown.
Methods We examined variation in the concentrations of selected trace gases over a range of
expiratory flows (50; 100; 250 ml/s) and after 30 second periods of breathold and paced hyperventilation. On-line measurement of breath samples from healthy volunteers (n¼10) was
performed by proton transfer mass spectrometry.
Results Exhaled acetone increased with higher expiratory flow rate (805, 838, 898 ppb, p¼0.02).
Levels of methanol (206 vs 179 ppb, p<0.01), acetaldehyde (26 vs 22 ppb, p<0.01), ethanol (410
vs 208 ppb, p¼0.01) and dimethyl sulphide (113 vs 103 ncps, p<0.01) fell significantly following
30s hyperventilation. After 30 second breathold levels of methanol (206 vs 217 ppb, p¼0.02),
acetone (805 vs 869 ppb, p<0.01), isoprene (348 vs 390 ppb, p¼0.02) and dimethyl sulphide (113
vs 136 ncps, p¼0.02) increased significantly. Variation in respiratory parameters did not significantly alters the level of acetonitrile, propanol and butyric acid within the breath of healthy subjects.
Conclusions These findings demonstrate that respiratory manoeuvres significantly influence the
measured concentration of a number of exhaled VOCs that are of potential importance within the
clinical setting. Our results support the adoption of standardised practices for breath gas analysis
by on-line and real time mass spectrometry methods.
Analysis of volatile trace gases within exhaled
breath, for the purpose of non-invasive
disease detection and monitoring, is a rapidly
emerging field of research.1 2 Recent technological developments such as proton transfer
reaction‑mass spectrometry (PTR-MS) have
allowed on-line and real-time detection of
multiple trace gases in breath, leading to
novel discoveries in cancer, infectious disease
and metabolism.2 3
One of the greatest lessons on clinical
applicability of breath analysis has been the
recognition that multiple physiological variables can influence the quantification of
exhaled nitric oxide (NO), necessitating
international consensus guidelines for its
standardised measurement.4 There remains
however limited experimental evidence
defining the impact of confounding factors
which may influence the quantification of
other exhaled volatile trace gases.5 Herein we
present the finding of a study investigating
the influence of respiratory variables on the
on-line detection and quantification of
a judiciously selected and potentially clinically relevant panel of expiratory trace gases.
We examined the variation in the
concentrations of selected trace gases
(methanol, acetaldehyde, ethanol, acetone,
isoprene, acetonitrile, propanol, dimethyl
sulphide and butyric acid) over a range of
expiratory flows (50, 100, 250 ml/s) and after
the 30-s periods of breath hold and paced
hyperventilation. These volatiles were
compared to exhaled NO and carbon dioxide.
On-line measurement of breath samples
from healthy volunteers (n¼10) was
performed by combining PTR-MS (Ionimed
Analytik GmbH, Innsbruck, Austria) with
the LR2500 multiple-gas analyser (Logan
Research Ltd, Rochester, UK). Quantification
of trace gases by PTR-MS was achieved by
calibration experiments using accurately
known gas standards and a purpose built gas
Figure 1 Influence of respiratory physiological variables on the concentrations of selected trace gases
measured within the exhaled breath of healthy volunteers. Trace gas level are presented as the ratio of the
difference in breath manoeuvres versus their respective control breath measures at a flow rate of 50 ml/s.
Boshier PR, Priest
OH, Hanna
GB, et(or
al. Thorax
doi:10.1136/thx.2011.161208
1 of 2
Copyright
Article
author
their(2011).
employer)
2011. Produced by BMJ Publishing Group Ltd (& BTS) under licence.
Thorax: first published as 10.1136/thx.2011.161208 on 7 April 2011. Downloaded from http://thorax.bmj.com/ on June 4, 2020 by guest. Protected by copyright.
Influence of respiratory variables on the on-line detection of exhaled
trace gases by PTR-MS
calibration unit (Ionimed). (Further details of
methodology are provided as supplementary
digital content).
In contrast to NO, exhibiting an inverse
relationship with expiratory flow rate,
exhaled acetone increased with higher flows
(805 vs 838, 898 ppb, p¼0.02) (figure 1).
After a 30-s breath hold, levels of acetone
(805 vs 869 ppb, p<0.01), methanol (206 vs
217 ppb, p¼0.02), isoprene (348 vs 390 ppb,
p¼0.02) and dimethyl sulphide (113 vs 136
ncps, p¼0.02) increased significantly. Levels
of methanol (206 vs 179 ppb, p<0.01),
dimethyl sulphide (113 vs 103 ncps, p<0.01),
acetaldehyde (26 vs 22 ppb, p<0.01) and
ethanol (410 vs 208 ppb, p¼0.01) fell
significantly following the 30-s hyperventilation (figure 1). Variation in respiratory
parameters did not significantly alter the
levels of acetonitrile, propanol and butyric
acid (table 2 in online supplement).
This work constitutes the first concerted
attempt to discern the effect of ventilatory
variables on breath analysis by an on-line MSbased analytical technique. The principal
findings of this study are (i) PTR-MS evidence
for the flow dependency of exhaled acetone;
(ii) changing minute ventilation can both
increase and decrease the concentrations of
selected exhaled trace gases; and (iii) concentrations of certain volatiles were not
PostScript
Piers R Boshier,1 Oliver H Priest,1
George B Hanna,1 Nandor Marczin2,3
Medicine and Intensive Care, Imperial College London,
Chelsea and Westminster Hospital, London, UK;
3
Department of Anaesthetics, Harefield Hospital, The
Royal Brompton and Harefield NHS Foundation Trust,
Harefield, Middlesex, UK
Correspondence to Dr Nandor Marczin, Department of
Surgery and Cancer, Section of Anaesthetics, Pain
Medicine and Intensive Care, Imperial College London,
Chelsea and Westminster Hospital, London SW10 9NH,
UK; n.marczin@imperial.ac.uk
2 of 2
1.
2.
3.
< An additional table is published online only. To view this
file please visit the journal online (http://thorax.bmj.com).
4.
Competing interests None.
Ethics approval This study was conducted with the
approval of the Riverside Research Ethics Committee
(project reference number: 08/H0706/134).
Provenance and peer review Not commissioned;
externally peer reviewed.
1
Department of Surgery and Cancer, Imperial College
London, St Mary’s Hospital, London, UK; 2Department of
Surgery and Cancer, Section of Anaesthetics, Pain
REFERENCES
Accepted 9 February 2011
5.
Kharitonov SA, Barnes PJ. Exhaled biomarkers. Chest
2006;130:1541e6.
Amann A, Smith D, eds. Breath Analysis for Clinical
Diagnosis and Therapeutic Monitoring. Singapore:
World Scientific, 2005.
Lindinger W, Hansel A, Jordan A. On-line monitoring
of volatile organic compounds at pptv levels by means
of proton-transfer-reaction mass spectrometry
(PTR-MS)-medical applications, food control and
environmental research. Int J Mass Spectrom
1998;173:191e241.
American Thoracic Society; European
Respiratory Society. ATS/ERS recommendations for
standardized procedures for the online and offline
measurement of exhaled lower respiratory nitric oxide
and nasal nitric oxide, 2005. Am J Respir Crit Care
Med 2005;171:912e30.
Larstad MA, Toren K, Bake B, et al. Determination of
ethane, pentane and isoprene in exhaled air: effects of
breath-holding, flow rate and purified air. Acta Physiol
(Oxf) 2007;189:87e98.
Thorax 2011;-:1e2. doi:10.1136/thx.2011.161208
Boshier PR, Priest OH, Hanna GB, et al. Thorax (2011). doi:10.1136/thx.2011.161208
Thorax: first published as 10.1136/thx.2011.161208 on 7 April 2011. Downloaded from http://thorax.bmj.com/ on June 4, 2020 by guest. Protected by copyright.
significantly altered by respiratory manoeuvres in healthy volunteers.
These preliminary observations may have
important implications regarding the standardisation requirement for measuring and
reporting the concentrations of exhaled trace
gases in the future. Further larger studies
both in healthy and diseased subjects are
necessary to expand on these observations
and to provide mechanistic insights into
exchange kinetics of affected volatiles. Such
studies may help to further define the exact
role of on-line MS technologies in non-invasive diagnosis and monitoring pulmonary
and systemic diseases.
Background and Aim: Captivity alters the locomotor behavior of wild artiodactyls and affects the mechanical loading of the calcaneus; however, the resulting adaptive changes in calcaneus morphology have not been sufficiently studied to date. This study aimed to investigate the morphological and mechanical adaptive variations in the calcaneus of Saiga tatarica to understand further the functional adaptation of the calcaneus in wild artiodactyl to captivity.
Materials and Methods: Paired calcanei from autopsy samples of six captive wild artiodactyls (S. tatarica) and six domesticated artiodactyls (Ovis aries) were divided into skeletally immature and mature groups using X-ray evaluation of growth plate closure. High-resolution microcomputed tomography revealed a calcaneal diaphyseal cross-section. The mechanical and nanomorphological characteristics of the trabecular bone were determined by atomic force microscopy.
Results: The percent cortical bone area (%CA), cortical thickness ratio (CTR), and Young’s modulus (E) differed between species in the immature groups but not in the mature groups. S. tatarica had significantly higher growth rates for %CA, CTR, and E in the mid-shaft than O. aries (p < 0.05).
Conclusion: The calcaneus morphology of S. tatarica converges with that of domesticated O. aries during ontogeny. These results indicate that the calcaneus of wild artiodactyls can undergo potentially transitional changes during the short-term adaptation to captivity. The above parameters can be preliminarily identified as morphological signs of functional bone adaptation in artiodactyls.
Keywords: artiodactyl, bone functional adaptation, calcaneus, captivity, morphological variation, Saiga tatarica.
During excavations in 2021 and 2022 at the Gunthenen/Privоlnoe-1 settlement (Zelenogradsky district, Kaliningrad region), finds unusual for the land of the Prussians were made. The discovery here of a lead seal of the Drogichin type, act seals of the Novgorod / Pskov and Kyiv princes directly testify to the high degree of qualification of the local inhabitants. It is obvious that among them were merchants who understood the high importance of trade seals and were able to read the letters received from the Russian princes. One can only speculate about the content of this historically significant correspondence, possibly concerning both trade issues (deliveries of amber, for example) and other forms of intertribal contacts. The finds in the layer of the settlement of Curonian brooches speak in favor of the presence among the inhabitants of the settlement of Gunthenen/Privolnoye-1 of the northeastern neighbors of the Prussians - the Curonians, who participated in the protection of caravans going to Russia along the Neman trade route.
worked Example for Design and check a suitable beam column for a non sway pinned in a building frame with a flexible joint is 5.5m high, subjected to axial load of 650 KN and major axis moment of 50 KN.m at (top and bottom) and minor axis moment of 25 KN.m (top and bottom) in India PDF.
Bài báo tập trung nghiên cứu hiện trạng công tác quản lý rừng trên địa bàn huyện Sơn Dương, tỉnh Tuyên Quang. Các phương pháp nghiên cứu được sử dụng gồm: thu thập tổng hợp số liệu, điều tra, khảo sát thực tế, thống kê. Kết quả nghiên cứu cho thấy, trong thời gian qua, diện tích rừng trên địa bàn huyện có xu hướng tăng lên (tỷ lệ che phủ tăng từ 48,95% năm 2017 lên 51,5% năm 2019), tuy nhiên chỉ tập trung vào rừng trồng (tăng hơn 2 nghìn ha), còn rừng tự nhiên có xu hướng giảm nhẹ (gần 1 ha). Diện tích rừng được chia nhỏ để quản lý (trong đó hơn 55% diện tích rừng và đất lâm nghiệp do Ủy ban nhân dân các xã quản lý, 19,24% do các hộ gia đình – cá nhân quản lý, 14,09% do Ban quản lý rừng đặc dụng quản lý, còn lại do các tổ chức kinh tế và các tổ chức khác quản lý). Nghiên cứu cũng chỉ ra những hạn chế trong công tác quản lý rừng của địa phương (như: địa bàn quản lý rộng, thiếu nguồn nhân lực quản lý, cơ sở vật chất còn thiếu thốn…) từ đó đưa ra hệ thống các giải pháp đối với chính qu...
This concise review has made a discussion on different thermal and non-thermal techniques associated with novel food processing technologies. Further a focus has been made on 3D food printing for mass customized diet and personalized nutrition.
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