24 results on '"Sengupta, Deep"'
Search Results
2. Wildfire smoke impacts on indoor air quality assessed using crowdsourced data in California
- Author
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Liang, Yutong, Sengupta, Deep, Campmier, Mark J, Lunderberg, David M, Apte, Joshua S, and Goldstein, Allen H
- Subjects
Air Pollution ,Indoor ,California ,Crowdsourcing ,Environmental Exposure ,Environmental Monitoring ,Fires ,Humans ,Particulate Matter ,Smoke ,biomass burning ,PM2.5 ,indoor air ,exposure ,low-cost PM2.5 sensors - Abstract
Wildfires have become an important source of particulate matter (PM2.5 < 2.5-µm diameter), leading to unhealthy air quality index occurrences in the western United States. Since people mainly shelter indoors during wildfire smoke events, the infiltration of wildfire PM2.5 into indoor environments is a key determinant of human exposure and is potentially controllable with appropriate awareness, infrastructure investment, and public education. Using time-resolved observations outside and inside more than 1,400 buildings from the crowdsourced PurpleAir sensor network in California, we found that the geometric mean infiltration ratios (indoor PM2.5 of outdoor origin/outdoor PM2.5) were reduced from 0.4 during non-fire days to 0.2 during wildfire days. Even with reduced infiltration, the mean indoor concentration of PM2.5 nearly tripled during wildfire events, with a lower infiltration in newer buildings and those utilizing air conditioning or filtration.
- Published
- 2021
3. Multinational prospective cohort study over 18 years of the risk factors for ventilator-associated pneumonia in 9 Asian countries: INICC findings
- Author
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Rosenthal, Victor Daniel, Yin, Ruijie, Rodrigues, Camilla, Myatra, Sheila Nainan, Divatia, Jigeeshu Vasishth, Biswas, Sanjay K, Shrivastava, Anjana Mahesh, Kharbanda, Mohit, Nag, Bikas, Mehta, Yatin, Sarma, Smita, Todi, Subhash Kumar, Bhattacharyya, Mahuya, Bhakta, Arpita, Gan, Chin Seng, Low, Michelle Siu Yee, Kushairi, Marissa Bt Madzlan, Chuah, Soo Lin, Wang, Qi Yuee, Chawla, Rajesh, Jain, Aakanksha Chawla, Kansal, Sudha, Bali, Roseleen Kaur, Arjun, Rajalakshmi, Davaadagva, Narangarav, Bat-Erdene, Batsuren, Begzjav, Tsolmon, Basri, Mat Nor Mohd, Tai, Chian-Wern, Lee, Pei-Chuen, Tang, Swee-Fong, Sandhu, Kavita, Badyal, Binesh, Arora, Ankush, Sengupta, Deep, Tao, Lili, and Jin, Zhilin
- Published
- 2023
- Full Text
- View/download PDF
4. Emission factors for polycyclic aromatic hydrocarbons from laboratory biomass-burning and their chemical transformations during aging in an oxidation flow reactor
- Author
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Sengupta, Deep, Samburova, Vera, Bhattarai, Chiranjivi, Moosmüller, Hans, and Khlystov, Andrey
- Published
- 2023
- Full Text
- View/download PDF
5. Respiratory morbidity and mortality of traumatic cervical spinal cord injury at a level I trauma center in India
- Author
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Sengupta, Deep, Bindra, Ashish, Kumar, Niraj, Goyal, Keshav, Singh, Pankaj Kumar, Chaturvedi, Arvind, Malhotra, Rajesh, and Mishra, Ashwani Kumar
- Published
- 2021
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6. Comparison of Different Tidal Volumes for Ventilation in Patients with an Acute Traumatic Cervical Spine Injury
- Author
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Sengupta, Deep, Bindra, Ashish, Kapoor, Indu, Mathur, Purva, Gupta, Deepak, and Khan, Maroof
- Subjects
Neck -- Injuries ,Artificial respiration -- Methods -- Complications and side effects ,Spinal cord injuries -- Care and treatment ,Barotrauma -- Risk factors -- Prevention ,Pulmonary ventilation -- Health aspects -- Measurement ,Health - Abstract
Byline: Deep. Sengupta, Ashish. Bindra, Indu. Kapoor, Purva. Mathur, Deepak. Gupta, Maroof. Khan Background: There is scant literature comparing high tidal volume ventilation (HTV) over low tidal volume (LTV) ventilation [...]
- Published
- 2022
7. Brain Death Diagnosis for Potential Organ Donors During the Covid-19 Pandemic
- Author
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Chavali, Siddharth, Rath, Girija, Sengupta, Deep, and Dube, Surya
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Transplantation of organs, tissues, etc. -- Methods -- Complications and side effects ,Epidemics -- Statistics -- Control -- India ,Organ donors -- Health aspects ,Neurologic examination -- Methods ,Brain death -- Health aspects ,Health - Abstract
Byline: Siddharth. Chavali, Girija. Rath, Deep. Sengupta, Surya. Dube Formal brainstem reflex testing remains one of the most important procedures in identification and evaluation of patients who meet clinical criteria [...]
- Published
- 2021
8. Evaluation of the GCS-Pupils Score for PrOgnosis in trauMatic brAin injury- The COMA Study.
- Author
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Mahajan, Charu, Sengupta, Deep, Kapoor, Indu, Prabhakar, Hemanshu, Kumar, Vijay, Purohit, Shobha, Priya, Vansh, Srivastava, Shashi, Thakur, Deepali, Karnik, Hemangi, Sati, Hem Chandra, and Kalaivani, Mani
- Subjects
- *
RESEARCH , *INTENSIVE care units , *SCIENTIFIC observation , *CONFIDENCE intervals , *REFLEXES , *COMPARATIVE studies , *RISK assessment , *DESCRIPTIVE statistics , *GLASGOW Coma Scale , *BRAIN injuries , *ODDS ratio , *LOGISTIC regression analysis , *SENSITIVITY & specificity (Statistics) , *LONGITUDINAL method - Abstract
Glasgow Coma Scale-Pupils (GCS-P) score has been found to be strongly related to in-hospital mortality in retrospective studies. We hypothesized that GCS-P would be better prognosticator than Glasgow Coma Scale (GCS) in patients with traumatic brain injury (TBI). In this prospective, multicentric, observational study, GCS and GCS-P scores were noted in adult TBI patients at ICU admission. Demographic variables, relevant clinical history, clinical/radiological findings and ICU complications were also noted. Extended Glasgow Outcome scale was noted at hospital discharge and at 6 months post-injury. Logistic regression analysis was carried out to estimate the odds for poor outcome adjusted for covariates. Sensitivity, specificity, area under curve (AUC) and odds ratio are reported for poor outcome at estimated cutoff point. A total of 573 patients were included in this study. The predictive power for mortality, shown by the AUC, was 0.81 [95% CI: 0.77–0.85] for GCS and 0.81 [95% CI: 0.77–0.86] for GCS-P score, both being comparable. Similarly, the predictive ability for outcome at discharge and 6 months, the AUC-ROC for both GCS and GCS-P were comparable. GCS-P is a good predictor of mortality and poor outcome. However, the predictive performance of GCS and GCS-P for in-hospital mortality and functional outcome at discharge and at 6 months remains comparable. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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- View/download PDF
9. Customs Law
- Author
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Baisburd, Yohai, Boscariol, John, Cherniak, Cyndee B. Todgham, Forgue, David G., Fraedrich, Laura, Goodale, Geoffrey M., Hassan, Gwendolyn, Kanargelidis, Greg, Martinez, Christine H., Masse, Martin, McGrath, Matthew T., Morgan, Cortney O'Toole, Padierna-Peralta, Julia S., Salkeld, David, SenGupta, Deep, and Skinner, Christopher H.
- Published
- 2011
10. Customs Law
- Author
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Boscariol, John, Chen, Kelly, Cherniak, Cyndee B. Todgham, Fitzpatrick, Courtney, Fraedrich, Laura, Goodale, Geoffrey M., Kanargelidis, Greg, Martinez, Christine, Morgan, Cortney O'toole, Padierna-Peralta, Julia S., Salkeld, David, SenGupta, Deep, and Skinner, Christopher H.
- Published
- 2010
11. Optical Characterization of Fresh and Photochemically Aged Aerosols Emitted from Laboratory Siberian Peat Burning.
- Author
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Iaukea-Lum, Michealene, Bhattarai, Chiranjivi, Sengupta, Deep, Samburova, Vera, Khlystov, Andrey Y., Watts, Adam C., Arnott, William P., and Moosmüller, Hans
- Subjects
CARBONACEOUS aerosols ,ALBEDO ,AEROSOLS ,PEAT ,BIOMASS burning ,ABSORPTION coefficients ,RADIATIVE forcing - Abstract
Carbonaceous aerosols emitted from biomass burning influence radiative forcing and climate change. Of particular interest are emissions from high-latitude peat burning because amplified climate change makes the large carbon mass stored in these peatlands more susceptible to wildfires and their emission can affect cryosphere albedo and air quality after undergoing transport. We combusted Siberian peat in a laboratory biomass-burning facility and characterized the optical properties of freshly emitted combustion aerosols and those photochemically aged in an oxidation flow reactor (OFR) with a three-wavelength photoacoustic instrument. Total particle count increased with aging by a factor of 6 to 11 while the total particle volume either changed little (<8%) for 19 and 44 days of equivalent aging and increased by 88% for 61 days of equivalent aging. The aerosol single-scattering albedo (SSA) of both fresh and aged aerosol increased with the increasing wavelength. The largest changes in SSA due to OFR aging were observed at the shortest of the three wavelengths (i.e., at 405 nm) where SSA increased by less than ~2.4% for 19 and 44 days of aging. These changes were due to a decrease in the absorption coefficients by ~45%, with the effect on SSA somewhat reduced by a concurrent decrease in the scattering coefficients by 20 to 25%. For 61 days of aging, we observed very little change in SSA, namely an increase of 0.31% that was caused a ~56% increase in the absorption coefficients that was more than balanced by a somewhat larger (~71%) increase in the scattering coefficients. These large increases in the absorption and scattering coefficients for aging at 7 V are at least qualitatively consistent with the large increase in the particle volume (~88%). Overall, aging shifted the absorption toward longer wavelengths and decreased the absorption Ångström exponents, which ranged from ~5 to 9. Complex refractive index retrieval yielded real and imaginary parts that increased and decreased, respectively, with the increasing wavelength. The 405 nm real parts first increased and then decreased and imaginary parts decreased during aging, with little change at other wavelengths. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
12. Wildfire smoke impacts on indoor air quality assessed using crowdsourced data in California.
- Author
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Yutong Liang, Sengupta, Deep, Campmier, Mark J., Lunderberg, David M., Apte, Joshua S., and Goldstein, Allen H.
- Subjects
- *
INDOOR air quality , *WILDFIRE prevention , *AIR quality indexes , *WILDFIRES , *TOBACCO products , *PARTICULATE matter , *CIGARETTES , *SMOKE - Abstract
Wildfires have become an important source of particulate matter (PM2.5 < 2.5-µm diameter), leading to unhealthy air quality index occurrences in the western United States. Since people mainly shelter indoors during wildfire smoke events, the infiltration of wildfire PM2.5 into indoor environments is a key determinant of human exposure and is potentially controllable with appropriate awareness, infrastructure investment, and public education. Using time-resolved observations outside and inside more than 1,400 buildings from the crowdsourced PurpleAir sensor network in California, we found that the geometric mean infiltration ratios (indoor PM2.5 of outdoor origin/outdoor PM2.5) were reduced from 0.4 during non-fire days to 0.2 during wildfire days. Even with reduced infiltration, the mean indoor concentration of PM2.5 nearly tripled during wildfire events, with a lower infiltration in newer buildings and those utilizing air conditioning or filtration. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
13. Polar semivolatile organic compounds in biomass-burning emissions and their chemical transformations during aging in an oxidation flow reactor.
- Author
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Sengupta, Deep, Samburova, Vera, Bhattarai, Chiranjivi, Watts, Adam C., Moosmüller, Hans, and Khlystov, Andrey Y.
- Abstract
Semivolatile organic compounds (SVOCs) emitted from open biomass burning (BB) can contribute to chemical and physical properties of atmospheric aerosols and also may cause adverse health effects. The polar fraction of SVOCs is a prominent part of BB organic aerosols, and thus it is important to characterize the chemical composition and reactivity of this fraction. In this study, globally and regionally important representative fuels (Alaskan peat, Moscow peat, Pskov peat, eucalyptus, Malaysian peat, and Malaysian agricultural peat) were burned under controlled conditions using the combustion chamber facility at the Desert Research Institute (DRI). Gas- and particle-phase biomass-burning emissions were aged in an oxidation flow reactor (OFR) to mimic 5–7 d of atmospheric aging. Fresh and OFR-aged biomass-burning aerosols were collected on Teflon-impregnated glass fiber filters (TIGF) in tandem with XAD resin media for organic carbon speciation. The polar fraction extracted with dichloromethane and acetone was analyzed with gas chromatography mass spectrometry (GC-MS) for 84 polar organic compounds – including mono- and dicarboxylic acids, methoxylated phenols, aromatic acids, anhydrosugars, resin acids, and sterols. For all these compounds, fuel-based emission factors (EFs) were calculated for fresh and OFR-aged samples. The carbon mass of the quantified polar compounds was found to constitute 5 % to 7 % of the total organic compound mass. A high abundance of methoxyphenols (239 mg kg
−1 for Pskov peat; 22.6 % of total GC-MS characterized mass) and resin acids (118 mg kg−1 for Alaskan peat; 14.5 % of total GC-MS characterized mass) was found in peat-burning emissions (smoldering combustion). The concentration of some organic compounds (e.g., tetracosanoic acid) with a molecular weight (MW) above 350 g mol−1 decreased after OFR aging, while abundances of low-MW compounds (e.g., hexanoic acid) increased. This indicated a significant extent of fragmentation reactions in the OFR. Methoxyphenols decreased after OFR aging, while a significant increase (3.7 to 8.6 times) in the abundance of dicarboxylic acids emission factors (EFs), especially maleic acid (10 to 60 times), was observed. EFs for fresh and ratios from fresh-to-aged BB samples reported in this study can be used to perform source apportionment and predict processes occurring during atmospheric transport. [ABSTRACT FROM AUTHOR]- Published
- 2020
- Full Text
- View/download PDF
14. Deposition of brown carbon onto snow: changes in snow optical and radiative properties.
- Author
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Beres, Nicholas D., Sengupta, Deep, Samburova, Vera, Khlystov, Andrey Y., and Moosmüller, Hans
- Subjects
ALBEDO ,OPTICAL properties ,SNOW ,ATMOSPHERIC aerosols ,RADIATIVE forcing ,WILDFIRES ,MICROWAVE remote sensing ,MIE scattering - Abstract
Light-absorbing organic carbon aerosol – colloquially known as brown carbon (BrC) – is emitted from combustion processes and has a brownish or yellowish visual appearance, caused by enhanced light absorption at shorter visible and ultraviolet wavelengths (0.3µm≲λ≲0.5µm). Recently, optical properties of atmospheric BrC aerosols have become the topic of intense research, but little is known about how BrC deposition onto snow surfaces affects the spectral snow albedo, which can alter the resulting radiative forcing and in-snow photochemistry. Wildland fires in close proximity to the cryosphere, such as peatland fires that emit large quantities of BrC, are becoming more common at high latitudes, potentially affecting nearby snow and ice surfaces. In this study, we describe the artificial deposition of BrC aerosol with known optical, chemical, and physical properties onto the snow surface, and we monitor its spectral radiative impact and compare it directly to modeled values. First, using small-scale combustion of Alaskan peat, BrC aerosols were artificially deposited onto the snow surface. UV–Vis absorbance and total organic carbon (TOC) concentration of snow samples were measured for samples with and without artificial BrC deposition. These measurements were used to first derive a BrC (mass) specific absorption (m 2 g -1) across the UV–Vis spectral range. We then estimate the imaginary part of the refractive index of deposited BrC aerosol using a volume mixing rule. Single-particle optical properties were calculated using Mie theory, and these values were used to show that the measured spectral snow albedo of snow with deposited BrC was in general agreement with modeled spectral snow albedo using calculated BrC optical properties. The instantaneous radiative forcing per unit mass of total organic carbon deposited to the ambient snowpack was found to be 1.23 (+0.14/-0.11) W m -2 per part per million (ppm). We estimate the same deposition onto a pure snowpack without light-absorbing impurities would have resulted in an instantaneous radiative forcing per unit mass of 2.68 (+0.27/-0.22) W m -2 per ppm of BrC deposited. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
15. Polar semi-volatile organic compounds in biomass burning emissions and their chemical transformations during aging in an oxidation flow reactor.
- Author
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Sengupta, Deep, Samburova, Vera, Bhattarai, Chiranjivi, Watts, Adam C., Moosmüller, Hans, and Khlystov, Andrey Y.
- Abstract
Semi-volatile organic compounds (SVOCs) emitted from open biomass-burning (BB) can contribute to chemical and physical properties of atmospheric aerosols and also may cause adverse health effects. The polar fraction of SVOCs constitutes a significant part of BB organic aerosols, and thus it is important to characterize the chemical composition and reactivity of this fraction. In this study, globally and regionally important representative fuels (Alaskan peat, Moscow peat, Pskov peat, Eucalyptus, Malaysian peat, and Malaysian agricultural peat) were burned under controlled conditions using the combustion chamber facility at the Desert Research Institute (DRI). Gas- and particulate-phase biomass-burning emissions were aged in an oxidation flow reactor (OFR) to mimic 5-7 days of atmospheric aging. Fresh and OFR-aged biomass-burning aerosols were collected on Teflon impregnated glass fiber filters (TIGF) in tandem with XAD resin media for organic compound (OC) speciation. The polar fraction extracted with dichloromethane and acetone was analyzed with gas chromatography mass spectrometry (GC-MS) for 84 polar organic compounds - including mono and dicarboxylic acids, methoxylated phenols, aromatic acids, anhydrosugars, resin acids, and sterols. For all these compounds, fuel-based emission factors (EFs) were calculated for fresh and OFR-aged samples. The carbon mass of the quantified polar compounds was found to constitute 5 % to 7 % of the total OC mass. High abundance of methoxyphenols (239 mg kg
-1 for Pskov peat; 22.6 % of total GC-MS characterized mass) and resin acids (118 mg kg-1 for Pskov peat; 14.5 % of total GC-MS characterized mass) was found in peat burning emissions (smoldering combustion). Concentration of some organic compounds (e.g., tetracosanoic acid) with molecular weight (MW) above 350 g mol-1 decreased after the OFR aging, while abundances of low MW compounds (e.g., hexanoic acid) increased. This indicated a significant extent of fragmentation reactions in the OFR. Methoxyphenols decreased after OFR aging, while a significant increase (3.7 to 8.6 times) in abundance of dicarboxylic acids emission factors (EFs), especially maleic acid (10 to 60 times), was observed. EFs for fresh and ratios from fresh-to-aged BB samples reported in this study can be used to perform source apportionment and predict processes occurring during atmospheric transport. [ABSTRACT FROM AUTHOR]- Published
- 2020
- Full Text
- View/download PDF
16. Deposition of brown carbon onto snow: changes of snow optical and radiative properties.
- Author
-
Beres, Nicholas D., Sengupta, Deep, Samburova, Vera, Khlystov, Andrey Y., and Moosmüller, Hans
- Abstract
Light-absorbing organic carbon aerosol – colloquially known as brown carbon (BrC) – is emitted from combustion processes and has a brownish or yellowish visual appearance, caused by enhanced light absorption at shorter visible and ultraviolet wavelengths (0.3 μm ≲ λ ≲ 0.5 μm). Recently, optical properties of atmospheric BrC aerosols have become the topic of intense research, but little is known about how BrC deposition onto snow surfaces affects the spectral snow albedo, which can alter the resulting radiative forcing and in-snow photochemistry. Wildland fires in close proximity to the cryosphere, such as peatland fires that emit large quantities of BrC, are becoming more common at high latitudes, potentially affecting nearby snow and ice surfaces. In this study, we describe the artificial deposition of BrC aerosol with known optical, chemical, and physical properties onto the snow surface and we monitor its spectral radiative impact and compare it directly to modeled values. First, using small-scale combustion of Alaskan peat, BrC aerosols were artificially deposited onto the snow surface. UV-vis absorbance and total organic carbon (TOC) concentration of snow samples were measured for samples with and without artificial BrC deposition. These measurements were used to estimate the imaginary part of the refractive index of deposited BrC aerosol with a volume mixing rule. Single particle optical properties were calculated using Mie theory, and these values were used to show that the measured spectral snow albedo of snow with deposited BrC was in general agreement with modeled spectral snow albedo using calculated BrC optical properties. The instantaneous radiative forcing by impurities present in the snow before the deposition experiments was found to increase the instantaneous radiative forcing at the surface of the natural snow at our site by 1.23 (+0.14/−0.11) W m
−2 per ppm of BrC deposited. However, we estimate that deposition onto a clean snowpack without light-absorbing impurities would have resulted in a more than twice as large instantaneous radiative forcing of 2.68 (+0.27/−0.22) W m−2 per ppm of BrC deposited. [ABSTRACT FROM AUTHOR]- Published
- 2019
- Full Text
- View/download PDF
17. Modified Prone Positioning during Neurosurgery: Sphinx and Concorde Positions Revisited.
- Author
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Sengupta, Deep, Dube, Surya K., Rajagopalan, Vanitha, and Rath, Girija P.
- Published
- 2021
- Full Text
- View/download PDF
18. Baclofen for neurogenic fever in a patient with cerebral contusion
- Author
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Sengupta, Deep, Kapoor, Indu, Mahajan, Charu, and Prabhakar, Hemanshu
- Published
- 2019
- Full Text
- View/download PDF
19. Physical and chemical characterization of aerosol in fresh and aged emissions from open combustion of biomass fuels.
- Author
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Bhattarai, Chiranjivi, Samburova, Vera, Sengupta, Deep, Iaukea-Lum, Michealene, Watts, Adam C., Moosmüller, Hans, and Khlystov, Andrey Y.
- Subjects
BIOMASS burning ,AEROSOLS ,COMBUSTION ,CARBON monoxide ,OXIDATION - Abstract
Biomass burning (BB) emissions and their atmospheric oxidation products can contribute significantly to direct aerosol radiative forcing of climate. Limited knowledge of BB organic aerosol chemical and optical properties leads to large uncertainties in climate models. In this article, we describe the experimental setup and the main findings of a laboratory BB study aimed at comprehensive optical, physical, and chemical characterization of fresh and aged BB emissions. An oxidation flow reactor (OFR) was used to mimic atmospheric oxidation processes. The OFR was characterized in terms of OH⋅ production rate, particle transmission efficiency, and characteristic lifetimes of condensible compounds. Emission factors (EFs) of main air pollutants (particulate matter, organic carbon [OC], elemental carbon [EC], carbon monoxide [CO], and nitrogen oxides [NO
x ]) were determined for five globally and regionally important biomass fuels: Siberian (Russia), Florida (USA), and Malaysian peats; mixed conifer and aspen fuel from Fishlake National Forest, Utah, USA; and mixed grass and brush fuel representative of the Great Basin, Nevada, USA. Measured fuel-based EFs for OC ranged from 0.85 ± 0.24 to 6.56 ± 1.40 mg g−1 . Measured EFs for EC ranged from 0.02 ± 0.01 to 0.16 ± 0.01 mg g−1 . The ratio of organic mass to total carbon mass for fresh emissions from these fuels ranged from 1.04 ± 0.04 to 1.34 ± 0.24. The effect of OFR aging on aerosol optical properties, size distribution, and concentration is also discussed. Copyright © 2018 American Association for Aerosol Research [ABSTRACT FROM AUTHOR]- Published
- 2018
- Full Text
- View/download PDF
20. Light absorption by polar and non-polar aerosol compounds from laboratory biomass combustion.
- Author
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Sengupta, Deep, Samburova, Vera, Bhattarai, Chiranjivi, Kirillova, Elena, Mazzoleni, Lynn, Iaukea-Lum, Michealene, Watts, Adam, Moosmüller, Hans, and Khlystov, Andrey
- Subjects
ATMOSPHERIC aerosols ,SOOT ,LIGHT absorption ,BIOMASS burning ,COMBUSTION ,ORGANIC compounds ,CHEMICAL properties ,HEXANE - Abstract
Fresh and atmospherically aged biomass-burning (BB) aerosol mass is mostly comprised of strongly light-absorbing black carbon (BC) and of organic carbon (OC) with its light-absorbing fraction - brown carbon (BrC). There is a lack of data on the physical and chemical properties of atmospheric BB aerosols, leading to high uncertainties in estimates of the BB impact on air quality and climate, especially for BrC. The polarity of chemical compounds influences their fate in the atmosphere including wet/dry deposition and chemical and physical processing. So far, most of the attention has been given to the water-soluble (polar) fraction of BrC, while the non-polar BrC fraction has been largely ignored. In the present study, the light absorption properties of polar and non-polar fractions of fresh and aged BB emissions were examined to estimate the contribution of different-polarity organic compounds to the light absorption properties of BB aerosols. In our experiments, four globally and regionally important fuels were burned under flaming and smoldering conditions in the Desert Research Institute (DRI) combustion chamber. To mimic atmospheric oxidation processes (5-7 days), BB emissions were aged using an oxidation flow reactor (OFR). Fresh and OFR-aged BB aerosols were collected on filters and extracted with water and hexane to study absorption properties of polar and non-polar organic species. Results of spectrophotometric measurements (absorption weighted by the solar spectrum and normalized to mass of fuel consumed) over the 190 to 900 nm wavelength range showed that the non-polar (hexane-soluble) fraction is 2-3 times more absorbing than the polar (water-soluble) fraction. However, for emissions from fuels that undergo flaming combustion, an increased absorbance was observed for the water extracts of oxidized/aged emissions while the absorption of the hexane extracts was lower for the aged emissions for the same type of fuels. Absorption Ångström exponent (AAE) values, computed based on absorbance values from spectrophotometer measurements, were changed with aging and the nature of this change was fuel dependent. The light absorption by humic-like substances (HULIS) was found to be higher in fuels characteristic of the southwestern USA. The absorption of the HULIS fraction was lower for OFR-aged BB emissions. Comparison of the light absorption properties of different-polarity extracts (water, hexane, HULIS) provides insight into the chemical nature of BB BrC and its transformation during oxidation processes. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
21. Emissions from the Open Laboratory Combustion of Cheatgrass (Bromus Tectorum).
- Author
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Rennie, Megan, Samburova, Vera, Sengupta, Deep, Bhattarai, Chiranjivi, Arnott, W. Patrick, Khlystov, Andrey, and Moosmüller, Hans
- Subjects
CHEATGRASS brome ,COMBUSTION efficiency ,COMBUSTION ,ANALYTICAL chemistry ,FIRE ecology ,CHEMICAL models - Abstract
Cheatgrass (Bromus Tectorum) is a highly invasive species in the Great Basin of the Western USA that is increasing the frequency and intensity of wildland fires. Though cheatgrass plays a significant role in the fire ecology of the Great Basin, very little is known about its combustion emissions. The fresh smoke from 16 open laboratory burns of cheatgrass was analyzed using real-time measurements and filter analysis. We presented measured intensive optical properties of the emitted smoke, including absorption Ångström exponent (AAE), scattering Ångström exponent (SAE), single scattering albedo (SSA), and other combustion properties, such as modified combustion efficiency (MCE) and fuel-based emission factors (EFs). In addition, we gave a detailed chemical analysis of polar organic species in cheatgrass combustion emissions. We presented EFs that showed a large variation between fuels and demonstrated that analysis of combustion emissions for specific fuels was important for studying and modeling the chemistry of biomass-burning emissions. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
22. Multinational prospective cohort study of incidence and risk factors for central line-associated bloodstream infections over 18 years in 281 ICUs of 9 Asian countries.
- Author
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Rosenthal VD, Yin R, Rodrigues C, Myatra SN, Divatia JV, Biswas SK, Shrivastava AM, Kharbanda M, Nag B, Mehta Y, Sarma S, Todi SK, Bhattacharyya M, Bhakta A, Gan CS, Low MSY, Bt Madzlan Kushairi M, Chuah SL, Wang QY, Chawla R, Jain AC, Kansal S, Bali RK, Arjun R, Davaadagva N, Bat-Erdene I, Begzjav T, Mohd Basri MN, Tai CW, Lee PC, Tang SF, Sandhu K, Badyal B, Arora A, Sengupta D, Tao L, and Jin Z
- Subjects
- Humans, Risk Factors, Prospective Studies, Male, Female, Middle Aged, Asia epidemiology, Time Factors, Incidence, Aged, Risk Assessment, Adult, Cross Infection epidemiology, Cross Infection diagnosis, Catheter-Related Infections epidemiology, Catheter-Related Infections microbiology, Catheter-Related Infections diagnosis, Catheterization, Central Venous adverse effects, Intensive Care Units, Central Venous Catheters adverse effects
- Abstract
Background: Our objective was to identify central line (CL)-associated bloodstream infections (CLABSI) rates and risk factors (RF) in Asia., Methods: From 03/27/2004 to 02/11/2022, we conducted a multinational multicenter prospective cohort study in 281 ICUs of 95 hospitals in 44 cities in 9 Asian countries (China, India, Malaysia, Mongolia, Nepal, Pakistan, Philippines, Sri Lanka, Thailand, and Vietnam). For estimation of CLABSI rate we used CL-days as denominator and number of CLABSI as numerator. To estimate CLABSI RF for we analyzed the data using multiple logistic regression, and outcomes are shown as adjusted odds ratios (aOR)., Results: A total of 150,142 patients, hospitalized 853,604 days, acquired 1514 CLABSIs. Pooled CLABSI rate per 1000 CL-days was 5.08; per type of catheter were: femoral: 6.23; temporary hemodialysis: 4.08; jugular: 4.01; arterial: 3.14; PICC: 2.47; subclavian: 2.02. The highest rates were femoral, temporary for hemodialysis, and jugular, and the lowest PICC and subclavian. We analyzed following variables: Gender, age, length of stay (LOS) before CLABSI acquisition, CL-days before CLABSI acquisition, CL-device utilization ratio, CL-type, tracheostomy use, hospitalization type, ICU type, facility ownership and World Bank classifications by income level. Following were independently associated with CLABSI: LOS before CLABSI acquisition, rising risk 4% daily (aOR = 1.04; 95% CI = 1.03-1.04; p < 0.0001); number of CL-days before CLABSI acquisition, rising risk 5% per CL-day (aOR = 1.05; 95% CI 1.05-1.06; p < 0.0001); medical hospitalization (aOR = 1.21; 95% CI 1.04-1.39; p = 0.01); tracheostomy use (aOR = 2.02;95% CI 1.43-2.86; p < 0.0001); publicly-owned facility (aOR = 3.63; 95% CI 2.54-5.18; p < 0.0001); lower-middle-income country (aOR = 1.87; 95% CI 1.41-2.47; p < 0.0001). ICU with highest risk was pediatric (aOR = 2.86; 95% CI 1.71-4.82; p < 0.0001), followed by medical-surgical (aOR = 2.46; 95% CI 1.62-3.75; p < 0.0001). CL with the highest risk were internal-jugular (aOR = 3.32; 95% CI 2.84-3.88; p < 0.0001), and femoral (aOR = 3.13; 95% CI 2.48-3.95; p < 0.0001), and subclavian (aOR = 1.78; 95% CI 1.47-2.15; p < 0.0001) showed the lowest risk., Conclusions: The following CLABSI RFs are unlikely to change: country income level, facility-ownership, hospitalization type, and ICU type. Based on these findings it is suggested to focus on reducing LOS, CL-days, and tracheostomy; using subclavian or PICC instead of internal-jugular or femoral; and implementing evidence-based CLABSI prevention recommendations., Competing Interests: Declaration of conflicting interestsThe author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: All authors declare that don’t have any financial and personal relationships with other people or organizations that could inappropriately influence (bias) their work. All authors declare that don’t have potential competing interests, such as employment, consultancies, stock ownership, honoraria, paid expert testimony, patent applications/registrations, and grants or other funding. Submission of this article implies that the work described has not been published previously, that it is not under consideration for publication elsewhere, that its publication is approved by all authors and tacitly or explicitly by the responsible authorities where the work was carried out, and that, if accepted, it will not be published elsewhere in the same form, in English or in any other language, including electronically without the written consent of the copyright-holder.
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- 2024
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23. Evaluating the outcome of a bundle with 11 components and the INICC multidimensional approach in decreasing rates of central line-associated bloodstream infections across nine Asian countries.
- Author
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Rosenthal VD, Yin R, Myatra SN, Divatia JV, Biswas SK, Shrivastava AM, Perez V, Wang QY, Todi SK, Tang SF, Tai CW, Lee PC, Sengupta D, Sarma S, Sandhu K, Rodrigues C, Nag B, Mohd-Basri MN, Mehta Y, Kharbanda M, Kansal S, Jain AC, Davaadagva N, Chuah SL, Low MSY, Gan CS, Bt Madzlan Kushairi M, Bhattacharyya M, Bhakta A, Begzjav T, Bat-Erdene B, Bali RK, Badyal B, Arora A, Arjun R, Tao L, Jin Z, and Chawla R
- Abstract
Background: Central line-associated bloodstream infection (CLABSI) rates in intensive care units (ICUs) across Latin America exceed those in high-income countries significantly., Methods: We implemented the INICC multidimensional approach, incorporating an 11-component bundle, in 122 ICUs spanning nine Asian countries. We computed the CLABSI rate using the CDC/NSHN definition and criteria. The CLABSI rate per 1000 CL-days was calculated at baseline and throughout different phases of the intervention, including the 2nd month, 3rd month, 4-16 month, and 17-29 month periods. A two-sample t -test was employed to compare baseline CLABSI rates with intervention rates. Additionally, we utilized a generalized linear mixed model with a Poisson distribution to analyze the association between exposure and outcome., Results: A total of 124,946 patients were hospitalized over 717,270 patient-days, with 238,595 central line (CL)-days recorded. The rates of CLABSI per 1000 CL-days significantly decreased from 16.64 during the baseline period to 6.51 in the 2nd month (RR = 0.39; 95% CI = 0.36-0.42; p < 0.001), 3.71 in the 3rd month (RR = 0.22; 95% CI = 0.21-0.25; p < 0.001), 2.80 in the 4-16 month (RR = 0.17; 95% CI = 0.15-0.19; p < 0.001), and 2.18 in the 17-29 month (RR = 0.13; 95% CI = 0.11-0.15; p < 0.001) intervals. A multilevel Poisson regression model demonstrated a sustained, continuous, and statistically significant decrease in ratios of incidence rates, reaching 0.35 ( p < 0.0001) during the 17-29 month period. Moreover, the all-cause in-ICU mortality rate significantly decreased from 13.23% to 10.96% ( p = 0.0001) during the 17-29 month period., Conclusions: Our intervention led to an 87% reduction in CLABSI rates, with a 29-month follow-up., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
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- 2024
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24. Risk factors for mortality over 18 years in 317 ICUs in 9 Asian countries: The impact of healthcare-associated infections.
- Author
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Rosenthal VD, Jin Z, Rodrigues C, Myatra SN, Divatia JV, Biswas SK, Shrivastava AM, Kharbanda M, Nag B, Mehta Y, Sarma S, Todi SK, Bhattacharyya M, Bhakta A, Gan CS, Low MSY, Bt Madzlan Kushairi M, Chuah SL, Wang QY, Chawla R, Jain AC, Kansal S, Bali RK, Arjun R, Davaadagva N, Bat-Erdene B, Begzjav T, Mohd Basri MN, Tai CW, Lee PC, Tang SF, Sandhu K, Badyal B, Arora A, Sengupta D, and Yin R
- Subjects
- Adult, Child, Humans, Female, Prospective Studies, Intensive Care Units, Risk Factors, Hospitals, University, Delivery of Health Care, Pakistan epidemiology, Catheter-Related Infections epidemiology, Pneumonia, Ventilator-Associated, Cross Infection epidemiology, Urinary Tract Infections
- Abstract
Objective: To identify risk factors for mortality in intensive care units (ICUs) in Asia., Design: Prospective cohort study., Setting: The study included 317 ICUs of 96 hospitals in 44 cities in 9 countries of Asia: China, India, Malaysia, Mongolia, Nepal, Pakistan, Philippines, Sri Lanka, Thailand, and Vietnam., Participants: Patients aged >18 years admitted to ICUs., Results: In total, 157,667 patients were followed during 957,517 patient days, and 8,157 HAIs occurred. In multiple logistic regression, the following variables were associated with an increased mortality risk: central-line-associated bloodstream infection (CLABSI; aOR, 2.36; P < .0001), ventilator-associated event (VAE; aOR, 1.51; P < .0001), catheter-associated urinary tract infection (CAUTI; aOR, 1.04; P < .0001), and female sex (aOR, 1.06; P < .0001). Older age increased mortality risk by 1% per year (aOR, 1.01; P < .0001). Length of stay (LOS) increased mortality risk by 1% per bed day (aOR, 1.01; P < .0001). Central-line days increased mortality risk by 2% per central-line day (aOR, 1.02; P < .0001). Urinary catheter days increased mortality risk by 4% per urinary catheter day (aOR, 1.04; P < .0001). The highest mortality risks were associated with mechanical ventilation utilization ratio (aOR, 12.48; P < .0001), upper middle-income country (aOR, 1.09; P = .033), surgical hospitalization (aOR, 2.17; P < .0001), pediatric oncology ICU (aOR, 9.90; P < .0001), and adult oncology ICU (aOR, 4.52; P < .0001). Patients at university hospitals had the lowest mortality risk (aOR, 0.61; P < .0001)., Conclusions: Some variables associated with an increased mortality risk are unlikely to change, such as age, sex, national economy, hospitalization type, and ICU type. Some other variables can be modified, such as LOS, central-line use, urinary catheter use, and mechanical ventilation as well as and acquisition of CLABSI, VAE, or CAUTI. To reduce mortality risk, we shall focus on strategies to reduce LOS; strategies to reduce central-line, urinary catheter, and mechanical ventilation use; and HAI prevention recommendations.
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- 2023
- Full Text
- View/download PDF
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