The Experts below are selected from a list of 63738 Experts worldwide ranked by ideXlab platform
Peder Wolkoff - One of the best experts on this subject based on the ideXlab platform.
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assessment of indoor air quality problems in office like environments role of occupational health services
International Journal of Environmental Research and Public Health, 2018Co-Authors: P Carrer, Peder WolkoffAbstract:There is an increasing concern about indoor air quality (IAQ) and its impact on health, comfort, and work-performance in office-like environments and their workers, which account for most of the labor force. The Scientific Committee on Indoor Air Quality and Health of the ICOH (Int. Comm. Occup. Health) has discussed the assessment and management of IAQ problems and proposed a stepwise approach to be conducted by a multidisciplinary team. It is recommended to integrate the building assessment, inspection by walk-through of the office workplace, questionnaire survey, and environmental measurements, in that order. The survey should cover perceived IAQ, symptoms, and psychosocial working aspects. The outcome can be used for mapping the IAQ and to prioritize the order in which problems should be dealt with. Individual health surveillance in relation to IAQ is proposed only when periodical health surveillance is already performed for other risks (e.g., video display units) or when specific clinical examination of workers is required due to the occurrence of diseases that may be linked to IAQ (e.g., Legionnaire’s disease), recurrent inflammation, infections of eyes, Respiratory Airway effects, and sensorial disturbances. Environmental and personal risk factors should also be compiled and assessed. Workplace health promotion should include programs for smoking cessation and stress and IAQ management.
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Assessment of Indoor Air Quality Problems in Office-Like Environments: Role of Occupational Health Services
MDPI AG, 2018Co-Authors: P Carrer, Peder WolkoffAbstract:There is an increasing concern about indoor air quality (IAQ) and its impact on health, comfort, and work-performance in office-like environments and their workers, which account for most of the labor force. The Scientific Committee on Indoor Air Quality and Health of the ICOH (Int. Comm. Occup. Health) has discussed the assessment and management of IAQ problems and proposed a stepwise approach to be conducted by a multidisciplinary team. It is recommended to integrate the building assessment, inspection by walk-through of the office workplace, questionnaire survey, and environmental measurements, in that order. The survey should cover perceived IAQ, symptoms, and psychosocial working aspects. The outcome can be used for mapping the IAQ and to prioritize the order in which problems should be dealt with. Individual health surveillance in relation to IAQ is proposed only when periodical health surveillance is already performed for other risks (e.g., video display units) or when specific clinical examination of workers is required due to the occurrence of diseases that may be linked to IAQ (e.g., Legionnaire’s disease), recurrent inflammation, infections of eyes, Respiratory Airway effects, and sensorial disturbances. Environmental and personal risk factors should also be compiled and assessed. Workplace health promotion should include programs for smoking cessation and stress and IAQ management
Eric Lauga - One of the best experts on this subject based on the ideXlab platform.
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propulsion in a viscoelastic fluid
Physics of Fluids, 2007Co-Authors: Eric LaugaAbstract:Flagella beating in complex fluids are significantly influenced by viscoelastic stresses. Relevant examples include the ciliary transport of Respiratory Airway mucus and the motion of spermatozoa in the mucus-filled female reproductive tract. We consider the simplest model of such propulsion and transport in a complex fluid, a waving sheet of small amplitude free to move in a polymeric fluid with a single relaxation time. We show that, compared to self-propulsion in a Newtonian fluid occurring at a velocity UN, the sheet swims (or transports fluid) with velocity U∕UN=(1+De2ηs∕η)∕(1+De2), where ηs is the viscosity of the Newtonian solvent, η is the zero-shear-rate viscosity of the polymeric fluid, and De is the Deborah number for the wave motion, product of the wave frequency by the fluid relaxation time. Similar expressions are derived for the rate of work of the sheet and the mechanical efficiency of the motion. These results are shown to be independent of the particular nonlinear constitutive equations ...
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Propulsion in a viscoelastic fluid
Physics of Fluids, 2007Co-Authors: Eric LaugaAbstract:Flagella beating in complex fluids are significantly influenced by viscoelastic stresses. Relevant examples include the ciliary transport of Respiratory Airway mucus and the motion of spermatozoa in the mucus-filled female reproductive tract. We consider the simplest model of such propulsion and transport in a complex fluid, a waving sheet of small amplitude free to move in a polymeric fluid with a single relaxation time. We show that, compared to self-propulsion in a Newtonian fluid occurring at a velocity U_N, the sheet swims (or transports fluid) with velocity U / U_N = [1+De^2 (eta_s)/(eta) ]/[1+De^2], where eta_s is the viscosity of the Newtonian solvent, eta is the zero-shear-rate viscosity of the polymeric fluid, and De is the Deborah number for the wave motion, product of the wave frequency by the fluid relaxation time. Similar expressions are derived for the rate of work of the sheet and the mechanical efficiency of the motion. These results are shown to be independent of the particular nonlinear constitutive equations chosen for the fluid, and are valid for both waves of tangential and normal motion. The generalization to more than one relaxation time is also provided. In stark contrast with the Newtonian case, these calculations suggest that transport and locomotion in a non-Newtonian fluid can be conveniently tuned without having to modify the waving gait of the sheet but instead by passively modulating the material properties of the liquid.
P Carrer - One of the best experts on this subject based on the ideXlab platform.
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assessment of indoor air quality problems in office like environments role of occupational health services
International Journal of Environmental Research and Public Health, 2018Co-Authors: P Carrer, Peder WolkoffAbstract:There is an increasing concern about indoor air quality (IAQ) and its impact on health, comfort, and work-performance in office-like environments and their workers, which account for most of the labor force. The Scientific Committee on Indoor Air Quality and Health of the ICOH (Int. Comm. Occup. Health) has discussed the assessment and management of IAQ problems and proposed a stepwise approach to be conducted by a multidisciplinary team. It is recommended to integrate the building assessment, inspection by walk-through of the office workplace, questionnaire survey, and environmental measurements, in that order. The survey should cover perceived IAQ, symptoms, and psychosocial working aspects. The outcome can be used for mapping the IAQ and to prioritize the order in which problems should be dealt with. Individual health surveillance in relation to IAQ is proposed only when periodical health surveillance is already performed for other risks (e.g., video display units) or when specific clinical examination of workers is required due to the occurrence of diseases that may be linked to IAQ (e.g., Legionnaire’s disease), recurrent inflammation, infections of eyes, Respiratory Airway effects, and sensorial disturbances. Environmental and personal risk factors should also be compiled and assessed. Workplace health promotion should include programs for smoking cessation and stress and IAQ management.
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Assessment of Indoor Air Quality Problems in Office-Like Environments: Role of Occupational Health Services
MDPI AG, 2018Co-Authors: P Carrer, Peder WolkoffAbstract:There is an increasing concern about indoor air quality (IAQ) and its impact on health, comfort, and work-performance in office-like environments and their workers, which account for most of the labor force. The Scientific Committee on Indoor Air Quality and Health of the ICOH (Int. Comm. Occup. Health) has discussed the assessment and management of IAQ problems and proposed a stepwise approach to be conducted by a multidisciplinary team. It is recommended to integrate the building assessment, inspection by walk-through of the office workplace, questionnaire survey, and environmental measurements, in that order. The survey should cover perceived IAQ, symptoms, and psychosocial working aspects. The outcome can be used for mapping the IAQ and to prioritize the order in which problems should be dealt with. Individual health surveillance in relation to IAQ is proposed only when periodical health surveillance is already performed for other risks (e.g., video display units) or when specific clinical examination of workers is required due to the occurrence of diseases that may be linked to IAQ (e.g., Legionnaire’s disease), recurrent inflammation, infections of eyes, Respiratory Airway effects, and sensorial disturbances. Environmental and personal risk factors should also be compiled and assessed. Workplace health promotion should include programs for smoking cessation and stress and IAQ management
Jatinder K Juss - One of the best experts on this subject based on the ideXlab platform.
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hypoxia upregulates neutrophil degranulation and potential for tissue injury
Thorax, 2016Co-Authors: Kim Hoenderdos, Katharine M Lodge, Robert A Hirst, Cheng Chen, Stefano Gc Palazzo, Annette Emerenciana, Charlotte Summers, Adri Angyal, Linsey Porter, Jatinder K JussAbstract:Background The inflamed bronchial mucosal surface is a profoundly hypoxic environment. Neutrophilic Airway inflammation and neutrophil-derived proteases have been linked to disease progression in conditions such as COPD and cystic fibrosis, but the effects of hypoxia on potentially harmful neutrophil functional responses such as degranulation are unknown. Methods and results Following exposure to hypoxia (0.8% oxygen, 3 kPa for 4 h), neutrophils stimulated with inflammatory agonists (granulocyte-macrophage colony stimulating factor or platelet-activating factor and formylated peptide) displayed a markedly augmented (twofold to sixfold) release of azurophilic (neutrophil elastase, myeloperoxidase), specific (lactoferrin) and gelatinase (matrix metalloproteinase-9) granule contents. Neutrophil supernatants derived under hypoxic but not normoxic conditions induced extensive Airway epithelial cell detachment and death, which was prevented by coincubation with the antiprotease α-1 antitrypsin; both normoxic and hypoxic supernatants impaired ciliary function. Surprisingly, the hypoxic upregulation of neutrophil degranulation was not dependent on hypoxia-inducible factor (HIF), nor was it fully reversed by inhibition of phospholipase C signalling. Hypoxia augmented the resting and cytokine-stimulated phosphorylation of AKT, and inhibition of phosphoinositide 3-kinase (PI3K)γ (but not other PI3K isoforms) prevented the hypoxic upregulation of neutrophil elastase release. Conclusion Hypoxia augments neutrophil degranulation and confers enhanced potential for damage to Respiratory Airway epithelial cells in a HIF-independent but PI3Kγ-dependent fashion.
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Hypoxia upregulates neutrophil degranulation and potential for tissue injury.
Thorax, 2016Co-Authors: Hoenderdos K, Summers Charlotte, Lodge Katharine, Ra Hirst, Chen C, Palazzo Sgc, Emerenciana A, Angyal A, Porter L, Jatinder K JussAbstract:BACKGROUND: The inflamed bronchial mucosal surface is a profoundly hypoxic environment. Neutrophilic Airway inflammation and neutrophil-derived proteases have been linked to disease progression in conditions such as COPD and cystic fibrosis, but the effects of hypoxia on potentially harmful neutrophil functional responses such as degranulation are unknown. METHODS AND RESULTS: Following exposure to hypoxia (0.8% oxygen, 3 kPa for 4 h), neutrophils stimulated with inflammatory agonists (granulocyte-macrophage colony stimulating factor or platelet-activating factor and formylated peptide) displayed a markedly augmented (twofold to sixfold) release of azurophilic (neutrophil elastase, myeloperoxidase), specific (lactoferrin) and gelatinase (matrix metalloproteinase-9) granule contents. Neutrophil supernatants derived under hypoxic but not normoxic conditions induced extensive Airway epithelial cell detachment and death, which was prevented by coincubation with the antiprotease α-1 antitrypsin; both normoxic and hypoxic supernatants impaired ciliary function. Surprisingly, the hypoxic upregulation of neutrophil degranulation was not dependent on hypoxia-inducible factor (HIF), nor was it fully reversed by inhibition of phospholipase C signalling. Hypoxia augmented the resting and cytokine-stimulated phosphorylation of AKT, and inhibition of phosphoinositide 3-kinase (PI3K)γ (but not other PI3K isoforms) prevented the hypoxic upregulation of neutrophil elastase release. CONCLUSION: Hypoxia augments neutrophil degranulation and confers enhanced potential for damage to Respiratory Airway epithelial cells in a HIF-independent but PI3Kγ-dependent fashion.Supported by the British Lung Foundation, Papworth Hospital NHS Foundation Trust, BBSRC and the Cambridge NIHR-Biomedical Research Centre. CS was funded by Wellcome Trust Early Postdoctoral Research Fellowship for Clinician Scientists (WT101692MA)
Siamak Khorramymehr - One of the best experts on this subject based on the ideXlab platform.
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in silico investigation of sneezing in a full real human upper Airway using computational fluid dynamics method
Computer Methods and Programs in Biomedicine, 2019Co-Authors: Hamidreza Mortazavy Beni, Kamran Hassani, Siamak KhorramymehrAbstract:Abstract Background and objective Sneezing is one of the most critical conditions that can occur in the human upper Airway. As some reports confirm the injury to the human upper Respiratory Airway while sneezing. Therefore, the accurate study of the distribution of pressure and velocity in this case is of great importance. Methods In the present study, using a real human upper Airway model, the pressure and velocity of the airflow generated in the tract during the sneezing have been investigated. Also, considering the results from a spirometer device as a boundary condition in the simulation process, the calculations have become reliable. Results According to the results, during sneezing, taking into account that the average outlet flow rate from the mouth is 4.79 L/s, the velocity of outlet airflow from the mouth and nose reaches 5.3 and 8.4 m/s, respectively. These values were 11.5 and 19, respectively, when the desired maximum flow rate was 10.58 L/s. It can be concluded that the increasing of trachea flow rate, leads to higher percentage of the outlet flow rate from the nose . The highest average pressure and velocity have been occurred in the trachea. Among other salient results of this report, increased average static pressure of larynx to approximately 10 kPa can be pointed which indicates that this area is critical so that the thyroid cartilage defect is likely to occur. It is also noteworthy that the increase of speed at nasopharynx is up to 125 m/s so that the cross-section changing in this area leads the fluid acts as a jet flow. Due to the specific geometry of the nasal cavity, some streams similar to poor shocks are formed, these shocks get stronger by increasing of the flow rate. The thyroid cartilage and nasal cavity are exposed to maximum static pressure extremums, respectively. Conclusions We introduced a model simulating a normal sneezing for two cases using a healthy 30-year-old male person. We believe that the model should be applied for different persons and an atlas of data could be obtained from different cases. This may help the medical system to have more data about the sneezing process.