The Effect of Simulated Obstructive Apneas on Mechanical Characteristics of Lower Airways in Individuals with Asthma.

Increased negative intrathoracic pressure that occurs during pharyngeal obstruction can increase thoracic fluid volume that may contribute to lower airway narrowing in individuals with obstructive sleep apnea (OSA) and asthma. Our previous study showed that fluid accumulation in the thorax induced by simulated OSA can increase total respiratory resistance. However, the effect of fluid shift on lower airway narrowing has not been investigated. To examine the effect of fluid accumulation in the thorax on the resistance of the lower airway. Non-asthma participants and individuals with (un)controlled asthma were recruited and underwent a single-day experiment. A catheter with six pressure sensors was inserted through the nose to continuously measure pressure at different sites of the airway, while a pneumotachograph was attached to a mouthpiece to record airflow. To simulate obstructive apneas, participants performed 25 Mueller maneuvers (MMs) while lying supine. Using the recordings of pressure sensor and airflow, total respiratory (RT), lower respiratory components (RL), and upper airway (RUA) resistances were calculated before and after MMs. Generalized estimation equation method was used to find the predictors of RL among variables including age, sex, body mass index, and the effect of MMs and asthma. Eighteen participants were included. Performing MMs significantly increased RT (2.23 ± 2.08 cmH2O/L/s, p = 0.003) and RL (1.52 ± 2.00 cmH2O/L/s, p = 0.023) in participants with asthma, while only RL was increased in non-asthma group (1.96 ± 1.73 cmH2O/L/s, p = 0.039). We found the model with age, and the effect of MMs and asthma severity generated the highest correlation (R2 = 0.69, p < 0.001). We provide evidence that fluid accumulation in the thorax caused by excessive intrathoracic pressure increases RL in both non-asthma and asthma groups. The changes in RL were related to age, having asthma and the effect of simulated OSA. This can explain the interrelationship between OSA and asthma.

Designing and validating an experimental protocol to induce airway narrowing in older adults with and without asthma.

BACKGROUND: Persons with asthma may experience excessive airway narrowing due to exercise or exposure to cold air, worsening their daily functionality. Exercise has several benefits for asthma control, but it may induce airway narrowing in some persons with asthma. When combined with cold temperatures, it introduces another layer of challenges. Therefore, managing this interaction is crucial to increase the quality of life in individuals with asthma. The purpose of this study was to develop a reliable experimental protocol to assess the effects of exercise and cold air on airway narrowing in adults with asthma in a controlled and safe environment. METHODS: This study was a randomized cross-over study in adults with and without asthma. Participants underwent a protocol involving a 10-min seated rest, followed by a 10-min cycling on a stationary bike in different temperatures of 0, 10, or 20  ∘ C. The sequence of room temperatures was randomized, and there was a 30-min interval for recovery between each temperature transition. In each temperature, to measure lung function and respiratory symptoms, oscillometry and a questionnaire were used at 0 min (baseline), after 10 min of sitting and before starting biking (pre-exercise), and after 10 min of biking (post-exercise). At each room temperature, the changes in airway mechanics and asthma symptoms among baseline, pre-exercise, and post-exercise were compared with one-way repeated measures ANOVA or Friedman Rank Test. Within each arm, cardiac and thoraco-abdominal motion respiration signals were also measured continuously using electrodes and calibrated respiratory inductance plethysmographs, respectively. RESULTS: A total of 23 persons with asthma (11 females, age: 56.3 ± 10.9 years, BMI: 27.4 ± 5.7 kg/m2) and 6 healthy subjects (3 females, age: 61.8 ± 9.1 years, BMI: 28.5 ± 3.1 kg/m2) were enrolled in the study. Cold temperature of 0 ∘ C induced airway narrowing in those with and without asthma after 10 and 20 min, respectively. Exercise intervention had significant changes in airway narrowing in participants with asthma in the range of 10-20 ∘ C. Our results showed that in asthma, changes in subjective respiratory symptoms were due to both cold temperatures of 0 and 10 ∘ C and exercise in the 0-20 ∘ C range. Respiratory symptoms were not noticed among the healthy participants. CONCLUSION: In conclusion, our findings suggest that exposure to cold temperatures of 0 ∘ C could serve as a reliable method in the experimental protocol for inducing airway narrowing in asthma. The impact of exercise on airway narrowing was more variable among participants. Understanding these triggers in the experimental protocol is essential for the successful management of asthma in future studies.

A pilot study to assess the effects of preventing fluid retention in the legs by wearing compression stockings on overnight airway narrowing in mild asthma.

PURPOSE: Nocturnal asthma is a sign of asthma worsening and could be partially due to more fluid drawn into the thorax during sleep by gravitational force and/or pharyngeal collapse in those with obstructive sleep apnea. Wearing compression stockings during the day reduces fluid shift from the legs to the neck overnight. However, the potential effect of wearing compression stockings to reduce fluid accumulation in the leg and to improve nocturnal small airway narrowing in patients with asthma has not been investigated. This study investigates whether reducing leg fluid volume by wearing compression stockings during the day would attenuate small airway narrowing in patients with asthma before and after sleep. METHODS: We enrolled 11 participants with asthma. All participants underwent overnight polysomnography with or without wearing compression stockings for 2 weeks. Before and after sleep, leg fluid volume (LFV) was measured by bioelectrical impedance, and airway narrowing was primarily assessed by respiratory system resistance and reactance at 5 Hz (R5 and X5 respectively) using oscillometry. RESULTS: After 2 weeks of wearing compression stockings, the LFV measured in the evening was reduced (∆ = - 192.6 ± 248.3 ml, p = 0.02), and R5 and X5 improved (∆ = - 0.7 ± 0.9 cmH2O/L/s, p = 0.03 and 0.2 ± 1.4 cmH2O/L/s, p = 0.05 respectively). No changes were observed in the morning. CONCLUSIONS: Preventing fluid retention in the legs by wearing compression stockings for 2 weeks during the day, reduced LFV and airway narrowing in the evening in all participants with asthma, but not in the morning after sleep.

Ecological risk assessment and restoration area identification of Pengyang County on the basis of the landscape pattern and function.

The joint landscape ecological risk as well as ecological corridors for ecological restoration area identification is of great significance to the past evolution and future development of landscapes. Ecological risks were assessed based on the landscape pattern and functional changes in Pengyang County in 2000, 2010, and 2020; ecological restoration areas were divided based on ecological risks and security pattern. Results showed that the ecological risk types in Pengyang County were mainly low risk from 2000 to 2010 and distributed in the central region, while the high-risk areas increased from 2010 to 2020 and were concentrated in the southern residential area. According to a comprehensive assessment of the landscape ecological risks, an ecological security pattern consisting of 17 ecological source points and 34 potential ecological corridors with an average length of 6.57 km was identified. Three ecological restoration areas were eventually identified: mining restoration areas, mountain restoration area, and urban restoration area. Our results would provide an important perspective for the sustainable development of regional natural landscape resources.

Sleep Apnea Detection by Tracheal Motion and Sound, and Oximetry via Application of Deep Neural Networks.

Purpose: Sleep apnea (SA) is highly prevalent, but under diagnosed due to inaccessibility of sleep testing. To address this issue, portable devices for home sleep testing have been developed to provide convenience with reasonable accuracy in diagnosing SA. The objective of this study was to test the validity a novel portable sleep apnea testing device, BresoDX1, in SA diagnosis, via recording of trachea-sternal motion, tracheal sound and oximetry. Patients and Methods: Adults with a suspected sleep disorder were recruited to undergo in-laboratory polysomnography (PSG) and a simultaneous BresoDX1 recording. Data from BresoDX1 were collected and features related to breathing sounds, body motions and oximetry were extracted. A deep neural network (DNN) model was trained with 61-second epochs of the extracted features to detect apneas and hypopneas from which an apnea-hypopnea index (AHI) was calculated. The AHI estimated by BresoDX1 (AHIbreso) was compared to the AHI determined from PSG (AHIPSG) and the sensitivity and specificity of SA diagnosis were assessed at an AHIPSG ≥ 15. Results: Two-hundred thirty-three participants (mean ± SD) 50 ± 16 years of age, with BMI of 29.8 ± 6.6 and AHI of 19.5 ± 22.7, were included. There was a strong relationship between AHIbreso and AHIPSG (r = 0.91, p < 0.001). SA detection for an AHIPSG ≥ 15 was highly sensitive (90.0%) and specific (85.9%). Conclusion: We conclude that the DNN model we developed via recording and analyses of trachea-sternal motion and sound along with oximetry provides an accurate estimate of the AHIPSG with high sensitivity and specificity. Therefore, BresoDX1 is a simple, convenient and accurate portable SA monitoring device that could be employed for home SA testing in the future.

Potential Zoning of Construction Land Consolidation in the Loess Plateau Based on the Evolution of Human-Land Relationship.

Towns serve as the basic unit of implementation for comprehensive land consolidation and rehabilitation. The utilization of scaling law can provide a new perspective for construction land consolidation. From two perspectives of the town hierarchic system and the growth of a single town, this research applies the Rank-Size Rule and Allometric Scaling Law to analyze the scale structure, hierarchy and allometric scaling evolution relationship of population and construction land in the Loess Plateau at the town scale in 2000, 2010, and 2017. Furthermore, the consolidation potential of construction land is divided into five zones and puts forward recommendations for the comprehensive consolidation of the construction land. The results indicate: (1) The majority of towns have small or medium populations and 62% of the towns in the study show negative population growth. Geographically, the northern part has a smaller population size compared with the southern part. 96% of the towns show an increasing trend in the quantity of construction land, and the south and north parts of the study area have more construction land compared with the center part. The zone of the Valley Plain has the largest population size, and the zone of the Sandy and Desert Area has the largest quantity of construction land. (2) The rank-size distributions of both population and construction land comply with the power-law relation. The population hierarchy has changed from equilibrium to concentration, while the hierarchy of construction land shows an opposite pattern. So, the whole town hierarchic system of the Loess Plateau is gradually tending to the optimal distribution, which is the town hierarchic system gradually forming an ideal sequence structure. (3) The population-construction land relationship obeys the allometric scaling law, and the major allometric type is positive allometry. The human-land relationship tends to be coordinated, and the town system tends to be reasonable. The allometric scaling coefficient is not robust in different geographical areas, especially in Irrigated Agricultural Areas. Furthermore, 90% of the towns have weak coordination of human-land relationships, and 60% of the towns have a relatively faster growth rate of construction land than the relative growth (decline) rate of population. (4) The consolidation potential of construction land is divided into five types. High Consolidation Potential Area concentrates in the Eastern Loess Plateau, while Medium and Low Consolidation Potential Area concentrically distribute in the Western Loess Plateau. The Human-land Coordination Area has a small number and scattered spatial distribution. The land use of towns that are concentrated around prefecture-level cities or with unique resources is not intensive enough. The zoning of construction land consolidation potential based on the results of the allometric scale is in line with reality, and local governments should make use of the characteristics and trends of the town system to formulate planning schemes to promote the integrated development of urban and rural areas.

Association of Obstructive Apnea with Thoracic Fluid Shift and Small Airways Narrowing in Asthma During Sleep.

Rationale: Obstructive sleep apnea (OSA) is highly prevalent among patients with asthma, suggesting a pathophysiological link between the two, but a mechanism for this has not been identified. Hypothesis: Among patients with asthma, those with OSA will have greater overnight increases in thoracic fluid volume and small airways narrowing than those without OSA. Methods: We enrolled 19 participants with asthma: 9 with OSA (apnea-hypopnea index (AHI) ≥10) and 10 without OSA (AHI <10). All participants underwent overnight polysomnography. Before and after sleep, thoracic fluid volume was measured by bioelectrical impedance and small airways narrowing was primarily assessed by respiratory system reactance at 5Hz using oscillometry. Results: Patients with asthma and OSA (OSA group) had a greater overnight increase in thoracic fluid volume by 120.5 mL than patients without OSA (non-OSA group) (164.4 ± 44.0 vs 43.9 ± 47.3 mL, p=0.006). Compared to the non-OSA group, the OSA group had greater overnight decrease in reactance at 5Hz (-1.08 ± 0.75 vs 0.21 ± 0.27 cmH2O/L/s, p=0.02), and overnight increase in reactance area (14.81 ± 11.09 vs -1.20 ± 2.46 cmH2O/L, p=0.04), frequency dependence of resistance (1.02 ± 0.68 vs 0.05 ± 0.18 cmH2O/L/s, p=0.04), and resonance frequency (2.80 ± 4.14 vs -1.42 ± 2.13 cmH2O/L/s, p=0.04). Conclusion: Patients with asthma and co-existing OSA had greater overnight accumulation of fluid in the thorax in association with greater small airways narrowing than those without OSA. This suggests OSA could contribute to worsening of asthma at night by increasing fluid accumulation in the thorax.

Growth response of greenhouse-produced muskmelon and tomato to sub-surface drip irrigation and soil aeration management factors.

BACKGROUND: Hypoxia causes injury and yield loss. Soil aeration has been reported to accelerate the growth of plants and increase crop yield. The aim of this study was to examine growth response of greenhouse-produced muskmelon to 3 levels of sub-surface drip irrigation (I), 3 different installation depths of drip laterals in the soil (D), and 4 levels of supplemental soil aeration frequency (A). A fractional factorial experiment was designed to examine these treatment effects on marketable fresh fruit yield, leaf area index during 3 growth stages, and dry matter partitioning at harvest. In addition, we studied the response of fruit yield and dry matter of tomato to 2 levels of burial depths of subsurface tubing in combination with 3 frequency levels of soil aeration. RESULTS: Results showed that soil aeration can positively influence the yield, leaf area index, dry matter and irrigation use efficiency of the muskmelon (p < 0.05). The fruit yield of muskmelon and tomato were increased by 21.5 and 30.8% respectively with 1-d and 2-d aeration intervals compared with the no aeration treatment. CONCLUSIONS: The results suggest that soil aeration can positively impact the plant root zone environment and more benefits can be obtained with aeration for both muskmelon and tomato plants.

Identifying Driving Forces of Built-Up Land Expansion Based on the Geographical Detector: A Case Study of Pearl River Delta Urban Agglomeration.

Understanding the driving forces behind built-up land expansion is crucial in urban planning and management. Using the Pearl River Delta urban agglomeration as research area, four landscape metrics were used to analyze landscape characteristics of urban expansion from 1990 to 2015. Spatial autocorrelation analysis was used to study the characteristics of built-up land expansion, while geographical detector was employed to identify the driving forces of urban land growth and their interactions. The results show the extent of built-up land has been increasing, the structure has become more complex, the level of fragmentation has been increasing, and the aggregation degree is in decline. The built-up landscape index shows spatial heterogeneity occurring in the core and peripheral towns of cities, as well as in the core and peripheral areas of the entire region. Also, changes in the built-up landscape index indicate increased spatial aggregation occurring in the past 25 years. Results from the geographical detector show natural, socio-economic, and transportation-related factors have substantial influence on built-up land expansion. Elevation, slope, population density, change in population density, and road network density were shown to have high influencing power. The influencing powers of slope and change in population density were also found to be different from other factors, highlighting their important role in urban development. Also, there were two types of interactions found, enhance nonlinear and enhance bivariate interactions, indicating the compounding influence of interactions between significant determinants. This study provides a new perspective and methodological approach in evaluating the driving forces behind built-up land expansion and their interactions.

Influence of traffic accessibility on land use based on Landsat imagery and internet map: A case study of the Pearl River Delta urban agglomeration.

Taking the Pearl River Delta urban agglomeration, with its rapid economic and social development and dramatic changes in land use, as an example with which to conduct this research, this paper analyzes the influence of traffic accessibility on land use and socioeconomic development by using Internet maps, points of interest (POI), and data about land use and socioeconomic development. The results of this study are as follows: (1) the calculation results of traffic accessibility can reflect the real situation because spatial distribution has an obvious feature of circle-like structure, and the development level of each township has high consistency; (2) major change characteristics in land use are that cultivated and forest lands are decreasing, and construction land is increasing, and it is obvious that the increase of construction land is featured by spatial autocorrelation and clusters of construction areas along the city borders; (3) traffic accessibility has a significant impact on land use status and changes and socioeconomic development, while the number of facilities has weak impact on land use, which is a reflection of advanced infrastructure in the urban agglomeration; and (4) the construction of transport infrastructure promotes the transformation of land use from water to construction land, therefore, more emphasis should be placed on protecting the river system in future infrastructure construction so as to improve the ecological benefits in the river basin.

Spatio-temporal evolution of port opening in China's 40 years of reform and opening-up period.

In the past 40 years of reform and opening-up, China has developed from an economically closed country to a country that is highly dependent on foreign trade. From the perspective of spatiotemporal evolution, we analyze how port opening promoted China's reform and opening-up process. First, the port development process is divided into four periods. In the start-up period, the pilot open port policy created a platform for foreign cooperation and exchange. During the expansion period, port openings promoted the continuous optimization of the trade structure. In the cooperation period, port openings corresponded with the adjustment of China's overall industrial structure. During the optimization period, port openings provided guarantees for the implementation of a national development strategy. Second, we analyze the distribution of ports and their relationship with cross-border logistics and passenger flow. Based on data of foreign trade and passenger flow, a port openness degree measurement model includes port logistics intensity, passenger flow intensity and port city foreign-trade volume is constructed. There are significant types, geographical differences and grade differences of ports' openness.

Effect of soil aeration on root morphology and photosynthetic characteristics of potted tomato plants (Solanum lycopersicum) at different NaCl salinity levels.

BACKGROUND: Salt stress is one of the environmental factors that greatly limits crop production worldwide because high salt concentrations in the soil affect morphological responses and physiological and metabolic processes, including root morphology and photosynthetic characteristics. Soil aeration has been reported to accelerate the growth of plants and increase crop yield. The objective of this study was to examine the effects of 3 NaCl salinity levels (28, 74 and 120 mM) and 3 aeration volume levels (2.3, 4.6 and 7.0 L/pot) versus non-aeration and salinity treatments on the root morphology, photosynthetic characteristics and chlorophyll content of potted tomato plants. RESULTS: The results showed that both aeration volume and salinity level affected the root parameters, photosynthetic characteristics and chlorophyll content of potted tomato plants. The total length, surface area and volume of roots increased with the increase in aeration volume under each NaCl stress level. The effect was more marked in the fine roots (especially in ≤1 mm diameter roots). Under each NaCl stress level, the photosynthetic rate and chlorophyll content of tomato significantly increased in response to the aeration treatments. The net photosynthetic rate and chlorophyll a and t content increased by 39.6, 26.9, and 17.9%, respectively, at 7.0 L/pot aeration volume compared with no aeration in the 28 mM NaCl treatment. We also found that aeration could reduce the death rate of potted tomato plants under high salinity stress conditions (120 mM NaCl). CONCLUSIONS: The results suggest that the negative effect of NaCl stress can be offset by soil aeration. Soil aeration can promote root growth and increase the photosynthetic rate and chlorophyll content, thus promoting plant growth and reducing the plant death rate under NaCl stress conditions.

Analysis of Spatial Pattern Evolution and Influencing Factors of Regional Land Use Efficiency in China Based on ESDA-GWR.

In order to give an in-depth understanding of the contradictions arising from the land resource supply and demand, this study selected 30 provinces (some are autonomous regions or municipalities) in China to be the research unit, used the carbon emission as an undesirable output, and adopted the Super-SBM DEA model and ESDA-GWR method to research the evolution characteristics and influencing factors of land use efficiency in China in 2003-2013. The results indicated that: (1) The land use efficiency in China overall was moderately ineffective and the overall utilization level was low; (2) The Global Spatial Autocorrelation was instable and had maintained a high level; (3) The "hot spots" mainly being distributed in the southeast coastal regions and "cold spots" being found in the central and western regions, so that as time goes on, the pattern of "high in the east and low in the west" has been gradually formed and stabilized. (4) The GWR model analysis showed that the natural factors such as NDVI, DMSP/OLS and DEM have a significant impact on land use efficiency, thereby providing an important contribution to this study. For the eastern coastal areas, the emphasis should be improving their OT, PF and PGDP, for the western region, should focus on improving its comprehensive economic development level to improve the DMSP/OLS, while strengthening the ecological environment to improve the level of NDVI.

Comparing winter-time herbicide behavior and exports in urban, rural, and mixed-use watersheds.

The presence of pesticides in streams in winter, five to six years following bans on their municipal use suggests that complicated transport behaviour, such as subsurface retention and/or accumulation of pesticides and its release during storms, could be important for understanding recovery time frames following bans or legislation that aim to reduce chemical inputs. We investigated late fall and winter dynamics of four herbicides in paired urban and rural watersheds in Toronto, Canada during rainfall and snowmelt. The range of average concentrations and loads of the sum of atrazine, metolachlor, 2,4-D and mecoprop overlapped in the two types of watersheds, with slightly higher average concentrations in the rural watershed. Relatively consistent herbicide concentration-discharge patterns (i.e. dilution) were observed in the urban sub-watersheds during rainfall, while concentration-discharge patterns were much more variable in the rural watershed. This suggests relatively uniform transport pathways across the urban sub-watersheds, compared to the rural watershed. Concentration-discharge patterns of the neutral herbicides atrazine and metolachlor were similar in both watersheds during snowmelt, though varying discharge patterns resulted in divergent timings of peak concentrations. In contrast, the acidic pesticides 2,4-D and mecoprop, which are primarily associated with urban uses, showed much more variable behavior across both watersheds and merit further investigation. Overall, this work highlights the need to consider pesticide dynamics throughout the year in order to more thoroughly assess the long-term efficacy of legislation governing their use.

Assessing the Source-to-Stream Transport of Benzotriazoles during Rainfall and Snowmelt in Urban and Agricultural Watersheds.

While benzotriazoles (BTs) are ubiquitous in urban waters, their sources and transport remain poorly characterized. We aimed to elucidate the origin and hydrological pathways of BTs in Toronto, Canada, by quantifying three BTs, electrical conductivity, and δ18O in high-frequency streamwater samples taken during two rainfall and one snowmelt event in two watersheds with contrasting levels of urbanization. Average concentrations of total BTs (∑BT) were 1.3 to 110 times higher in the more urbanized Mimico Creek watershed relative to the primarily agricultural and suburban Little Rouge Creek. Strong correlations between upstream density of major roads and total BT concentrations or BT composition within all events implicate vehicle fluids as the key source of BTs in both watersheds. Sustained historical releases of BTs within the Mimico Creek watershed have likely led to elevated ∑BT in groundwater, with elevated concentrations observed during baseflow that are diluted by rainfall and surface runoff. In contrast, relatively constant concentrations, caused by mixing of equally contaminated baseflow and rainfall/surface runoff, are observed in the Little Rouge Creek throughout storm hydrographs, with an occasional first flush occurring at a subsite draining suburban land. During snowmelt, buildup of BTs in roadside snowpiles and preferential partitioning of BTs to the liquid phase of a melting snowpack leads to early peaks in ∑BT in both streams, except the sites in the Little Rouge Creek with low levels of vehicle traffic. Overall, a history of BT release and land use associated with urbanization have led to higher levels of BTs in urban areas and provide a glimpse into future BT dynamics in mixed use, (sub)urbanizing areas.

Spatial and temporal pattern of pesticides in the global atmosphere.

As part of the Global Atmospheric Passive Sampling (GAPS) study, XAD-resin based passive samplers are being deployed for consecutive one-year periods at numerous sites on all seven continents to determine annually averaged concentrations of persistent organic pollutants. Concentrations of banned organochlorine pesticides as well as a number of current-use pesticides in samples from the first four years, roughly coinciding with 2005, 2006, 2007 and 2008, show distinct spatial and temporal patterns. Whereas organochlorine pesticides such as alpha- and gamma-hexachlorocyclohexane, endosulfans, DDT and its metabolites, and chlordane-related compounds tend to be more prevalent in developing countries, especially in Asia, concentrations of current use pesticides such as trifluralin and chlorothalonil are often higher in Europe and North America. Based on 15 stations with four years of data, levels of hexachlorobenzene, hexachlorocyclohexanes and chlordanes decline in most world regions, which may reflect decreased usage in response to global restrictions. Levels of organochlorine pesticides in India, however, remain exceptionally high. Concentrations of alpha-endosulfan, chlorothalonil and trifluralin decrease in the European atmosphere during the sampling periods, indicating reduced usage. Consistently high alpha/gamma-HCH ratios in air samples from high Northern latitudes confirm that re-volatilization from the Arctic Ocean is a significant source of alpha-HCH. The highest levels of alpha-HCH, however, occur in conjunction with high gamma-HCH levels, suggesting that lindane use is now the major source of alpha-HCH to the global atmosphere. Although a wide variety of sampling site types aids in characterizing the entire global concentration variability of a pesticide, it also increases greatly the number of sites required for a robust regional differentiation.