scholarly journals Evaluation of the Submicron Particles Distribution Between Mountain and Urban Site: Contribution of the Transportation for Defining Environmental and Human Health Issues

2019 ◽  
Vol 16 (8) ◽  
pp. 1339 ◽  
Author(s):  
Maurizio Manigrasso ◽  
Carmela Protano ◽  
Stefano Martellucci ◽  
Vincenzo Mattei ◽  
Matteo Vitali ◽  
...  
Keyword(s):  
Respiratory Tract ◽  
Ultrafine Particle ◽  
Submicron Particles ◽  
Aerosol Size Distribution ◽  
Urban Site ◽  
Cumulative Number ◽  
Human Respiratory Tract ◽  
Mountain Site ◽  
The Difference

Transportation is one of the main causes of atmospheric pollution, especially in downtown big cities. Researchers usually point their attention to gaseous and/or particulate matter pollutants. This paper investigated the role of submicron particles, particularly the fraction ranging between 5–560 nm, in aerosol chemistry for identifying the contribution of autovehicular traffic and investigating the doses deposited in the human respiratory tract. Measurements carried out by two Fast Mobility Particle Sizer (FMPS, TSI) analyzers were simultaneously performed at two different sampling sites (an urban and a mountain site) during workdays and weekends in July. The total particle number (2–2.5 times higher in the urban site), the aerosol size distribution (different modes during the day), and the ultrafine/non-ultrafine particle ratios (ranging between 2–4 times between two sites) were investigated and discussed in relationship to the high autovehicular traffic in Rome and the almost null anthropogenic emissions at the mountain site, as well as the differing contributions of both to the “fresh nucleation” and to “aged aerosol”. Furthermore, the regional cumulative number doses deposited in the human respiratory tract were studied for both sites: The difference between the urban/mountain site was very high (up to 15 fold), confirming the pollutant role of transportation.

scholarly journals Population Bottlenecks and Intra-host Evolution During Human-to-Human Transmission of SARS-CoV-2

2021 ◽  
Vol 8 ◽  
Author(s):  
Daxi Wang ◽  
Yanqun Wang ◽  
Wanying Sun ◽  
Lu Zhang ◽  
Jingkai Ji ◽  
...  
Keyword(s):  
Respiratory Tract ◽  
Stochastic Dynamics ◽  
The Novel ◽  
Population Bottlenecks ◽  
Human Respiratory Tract ◽  
Human Coronavirus ◽  
Active Viral Replication ◽  
Host Evolution ◽  
Replication Activity

The emergence of the novel human coronavirus, SARS-CoV-2, causes a global COVID-19 (coronavirus disease 2019) pandemic. Here, we have characterized and compared viral populations of SARS-CoV-2 among COVID-19 patients within and across households. Our work showed an active viral replication activity in the human respiratory tract and the co-existence of genetically distinct viruses within the same host. The inter-host comparison among viral populations further revealed a narrow transmission bottleneck between patients from the same households, suggesting a dominated role of stochastic dynamics in both inter-host and intra-host evolutions.

Quantitative deposition of ultrafine stable particles in the human respiratory tract

1985 ◽  
Vol 58 (1) ◽  
pp. 223-229 ◽  
Author(s):  
F. J. Wilson ◽  
F. C. Hiller ◽  
J. D. Wilson ◽  
R. C. Bone
Keyword(s):  
Respiratory Tract ◽  
Particle Deposition ◽  
Theoretical Models ◽  
Respiratory Pattern ◽  
Normal Male ◽  
Human Respiratory Tract ◽  
Size Fractions ◽  
Inhaled Particles ◽  
The Difference ◽  
Stable Particles

Theoretical models of particle deposition in the respiratory tract predict high fractional deposition for particles of less than 0.1 micron, but there are few confirming experimental data for those predictions. We have measured the deposition fraction of a nonhygroscopic aerosol in the human respiratory tract. The aerosol had a count mean diameter of 0.044 micron SD of 1.93, as measured with an electrical aerosol analyzer, and was produced from a 0.01% solution of bis(2-ethylhexyl) sebacate using a condensation generator. Subjects inhaled the aerosol using a controlled respiratory pattern of 1 liter tidal volume, 12/min. Deposition was calculated as the difference in concentration between inhaled and exhaled aerosol of five size fractions corrected for system deposition and dead-space constants. Three deposition studies were done on each of five normal male volunteers. Means (+/- SE) for the five size fractions were 0.024 micron, 0.71 +/- 0.06; 0.043 micron, 0.62 +/- 0.06; 0.075 micron, 0.53 +/- 0.05; 0.13 micron, 0.44 +/- 0.04; and 0.24 micron, 0.37 +/- 0.06. These data demonstrate that deposition of inhaled particles in the 0.024- to 0.24-micron size range is high and increases with decreasing size. These observations agree with and validate predictions of mathematical models.

scholarly journals A Computer Model for the Simulation of Nonspherical Particle Dynamics in the Human Respiratory Tract

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Robert Sturm
Keyword(s):  
Respiratory Tract ◽  
Particle Deposition ◽  
Submicron Particles ◽  
Nonspherical Particles ◽  
Aerodynamic Diameter ◽  
Human Respiratory Tract ◽  
Nonspherical Particle ◽  
Total Deposition ◽  
Aspect Ratios ◽  
Walk Algorithm

In the study presented here deposition of spheres and nonspherical particles with various aspect ratios (0.01–100) in the human respiratory tract was theoretically modeled. Shape of the nonspherical particles was considered by the application of the latest aerodynamic diameter concepts. Particle deposition was predicted by using a stochastic model of the lung geometry and simulating particle transport trajectories according to the random-walk algorithm. Concerning fibers total deposition is significantly enhanced with respect to that of spheres for μm-sized particles, whereby at normal breathing conditions peripheral lung compartments serve as primary deposition targets. In the case of oblate disks, total deposition becomes mostly remarkable for submicron particles, with the bronchioli and alveoli being targeted to a high extent. Enhancement of the aerodynamic diameter and/or flow rate generally causes a displacement of deposition maxima from peripheral to more proximal lung regions. From these findings, it can be concluded that these particle classes may represent tremendous occupational hazards, especially if they are attached with radioactive elements or heavy metals.

scholarly journals RELATIONSHIP BETWEEN GROWTH RATE AND DIFFERENT TYPES OF INFECTION IN CHILDREN UNDER 5 YEARS ON WEST PAPUA

2017 ◽  
Vol 6 (5) ◽  
pp. 109
Author(s):  
Fransiskus Aryo Pratomo
Keyword(s):  
Weight Gain ◽  
Tract Infection ◽  
Respiratory Tract ◽  
Upper Respiratory Tract ◽  
West Papua ◽  
Negative Effect ◽  
Weight Gain Data ◽  
Upper Respiratory ◽  
The Difference

Malnutrition is still a significant problem in the world and in Indonesia. Among the factors underlying it, the role of growth faltering is often underestimated. Considering infection as a factor that affects growth and that Indonesia is endemic to various different infectious diseases, to understand its role, a study on infants is conducted using using longitudinal study design in the Sumuri District, Bintuni Bay Regency, West Papua Province. A total of 138 children aged 6 months to 5 years is followed for 6 months in February to August 2014. Weight gain data and frequency of infection is collected, with the infections divided into four category of disease: upper respiratory tract infection, skin infection, gastroenteritis, and malaria. These data are gathered by Puskesmas daily and monthly records followed by home visit. This study found that the prevalence of malnutrition for the area covered by Puskesmas Tanah Merah is 15.9% for moderate malnutrition and 2.9% for severe malnutrition, with the mean SD value in the beginning of the study -1.15 and at the end of study -1.12, with the difference of SD value calculated as weight gain. Total incidence of infections and mean duration of each infection is then compiled and calculated with weight gain data using linear regression method statistical test to understand the difference of role of each infection to weight gain. The result of the study shows that gastroenteritis has a significant negative effect to weight gain and upper respiratory tract infection has a negative effect to weight gain on children in the villages handled by Puskesmas Tanah Merah West Papua.

scholarly journals The Effect of Inhalation Volume and Breath-Hold Duration on the Retention of Nicotine and Solanesol in the Human Respiratory Tract and on Subsequent Plasma Nicotine Concentrations During Cigarette Smoking

2004 ◽  
Vol 21 (4) ◽  
pp. 240-249 ◽  
Author(s):  
AK Armitage ◽  
M Dixon ◽  
BE Frost ◽  
DC Mariner ◽  
NM Sinclair
Keyword(s):  
Respiratory Tract ◽  
Systemic Circulation ◽  
Breath Hold ◽  
Human Respiratory Tract ◽  
Nicotine Concentration ◽  
Plasma Nicotine ◽  
Series Of Experiments ◽  
The Difference ◽  
Inhalation Volume ◽  
Breath Hold Duration

AbstractThe influence of inhalation depth and breath-hold duration on the retention of nicotine and solanesol in the human respiratory tract and on nicotine uptake was studied in ten cigarette smokers. In a first series of experiments, the subjects took seven puffs from a 10 mg ‘tar’ yield, test cigarette and a fixed volume of air (0, 75, 250, 500 or 1000 mL, as required by the protocol) was inhaled after each puff in order to give a controlled ‘depth’ of inhalation. The inhalation was drawn from a bag containing the required volume of air. Following a 2 s breath-hold, subjects exhaled normally, with the first exhalation after each puff passing through a single acidified filter pad for collection of the non-retained nicotine and solanesol. Blood samples were taken before and at intervals during and after smoking for the sessions with 0, 75 and 500 mL inhalation volumes for determination of plasma nicotine and carboxyhaemoglobin levels. Another series of experiments was conducted with a fixed inhalation volume (500 mL) and two further breath-hold durations (0 and 10 s) in addition to 2 s from above. Nicotine and solanesol retentions were measured for each breath-hold condition. The amounts of nicotine retained within the respiratory system, expressed as a percentage of the amount taken into the mouth, were consistently higher than the corresponding values for solanesol in all five inhalation conditions (0-1000 mL, 2 s breath-hold). Nicotine retention increased from 46.5% at zero inhalation to 99.5% at 1000 mL inhalation (2 s breath-hold) and from 98.0% at zero breath-hold to 99.9% at 10 s breath-hold (500 mL inhalation). Solanesol retention increased from 34.2% at zero inhalation volume to 71.9% at 1000 mL inhalation (2 s breath-hold) and from 51.8% at zero breath-hold to 87.6% at 10 s breath-hold (500 mL inhalation). Plasma nicotine decreased from pre-smoking levels after zero inhalation indicating that the nicotine retained within the mouth was poorly absorbed into the systemic circulation. After 75 mL inhalation, plasma nicotine levels were significantly greater than for zero inhalation but not significantly less than after 500 mL inhalation except at the time of maximum nicotine concentration. As in every experimental condition, a higher percentage of nicotine than solanesol was retained within the respiratory tract, it was concluded that the difference in retention of the moderately volatile nicotine and the non-volatile solanesol is consistent with the concept of nicotine evaporation from smoke particles and the subsequent efficient retention in the airways of gaseous nicotine. The retention of solanesol followed the expected pattern of particulate deposition i.e., an increase with both increasing depth of inhalation and breath-hold duration. However, nicotine retention was almost complete even at shallow inhalations and short breath-hold durations.

The role of differential phase contrast in electron microscopy

1978 ◽  
Vol 36 (1) ◽  
pp. 176-177
Author(s):  
E.M. Waddell ◽  
J.N. Chapman ◽  
R.P. Ferrier
Keyword(s):  
Phase Contrast ◽  
Practical Method ◽  
Position Vector ◽  
Differential Phase ◽  
Pure Phase ◽  
Differential Phase Contrast ◽  
The Difference ◽  
Image Position ◽  
First Moment

Dekkers and de Lang (1977) have discussed a practical method of realising differential phase contrast in a STEM. The method involves taking the difference signal from two semi-circular detectors placed symmetrically about the optic axis and subtending the same angle (2α) at the specimen as that of the cone of illumination. Such a system, or an obvious generalisation of it, namely a quadrant detector, has the characteristic of responding to the gradient of the phase of the specimen transmittance. In this paper we shall compare the performance of this type of system with that of a first moment detector (Waddell et al.1977).For a first moment detector the response function R(k) is of the form R(k) = ck where c is a constant, k is a position vector in the detector plane and the vector nature of R(k)indicates that two signals are produced. This type of system would produce an image signal given bywhere the specimen transmittance is given by a (r) exp (iϕ (r), r is a position vector in object space, ro the position of the probe, ⊛ represents a convolution integral and it has been assumed that we have a coherent probe, with a complex disturbance of the form b(r-ro) exp (iζ (r-ro)). Thus the image signal for a pure phase object imaged in a STEM using a first moment detector is b2 ⊛ ▽ø. Note that this puts no restrictions on the magnitude of the variation of the phase function, but does assume an infinite detector.

On the Role of Transferrin in 67Ga Uptake by Tumor Cells

1988 ◽  
Vol 27 (04) ◽  
pp. 151-153
Author(s):  
P. Thouvenot ◽  
F. Brunotte ◽  
J. Robert ◽  
L. J. Anghileri
Keyword(s):  
Specific Binding ◽  
Subcellular Fractionation ◽  
Animal Blood ◽  
Tumor Bearing ◽  
Cell Structures ◽  
The Difference ◽  
Sarcoma Cells ◽  
In Vitro Uptake

In vitro uptake of 67Ga-citrate and 59Fe-citrate by DS sarcoma cells in the presence of tumor-bearing animal blood plasma showed a dramatic inhibition of both 67Ga and 59Fe uptakes: about ii/io of 67Ga and 1/5o of the 59Fe are taken up by the cells. Subcellular fractionation appears to indicate no specific binding to cell structures, and the difference of binding seems to be related to the transferrin chelation and transmembrane transport differences

REFLECTION COEFFICIENT OF AN ELECTROMAGNETIC WAVE IN CONDUCTIVE MEDIA

2018 ◽  
pp. 100-106
Author(s):  
M. S. Sudakova ◽  
M. L. Vladov ◽  
M. R. Sadurtdinov
Keyword(s):  
Reflection Coefficient ◽  
Ground Penetrating Radar ◽  
Electromagnetic Waves ◽  
Water Contamination ◽  
Survey Design ◽  
Direct And Inverse Problems ◽  
The Difference ◽  
Ground Penetrating ◽  
Ideal Dielectric

Within the ground penetrating radar bandwidth the medium is considered to be an ideal dielectric, which is not always true. Electromagnetic waves reflection coefficient conductivity dependence showed a significant role of the difference in conductivity in reflection strength. It was confirmed by physical modeling. Conductivity of geological media should be taken into account when solving direct and inverse problems, survey design planning, etc. Ground penetrating radar can be used to solve the problem of mapping of halocline or determine water contamination.

Sign in / Sign up

Export Citation Format

Share Document