Biophysical Surface Properties Research Articles

The Biophysical Properties of the Fruit Cuticles of Six Pear Cultivars during Postharvest Ripening

Pears are abundant in bioactive compounds, which exert favorable effects on human health. The biophysical attributes of fruit cuticles are pivotal in determining fruit quality, storability, and susceptibility to mold growth. This study aimed to elucidate the biophysical properties of six pear cultivars, ‘Conference’, ‘Celina’, ‘Abate Fetel’, ‘Packham’s Triumph’, ‘Sweet Sensation’, and ‘Williams’. Two maturity stages, unripe and fully ripened, were investigated. Furthermore, the efficacy of trimethyl-chitosan-coated pear surfaces in preventing Penicillium expansum (P. expansum) growth was assessed. Basic maturity indices (CIE color, ethylene evolution, firmness, soluble solids), cuticle contact angle, roughness, and zeta potential were analyzed. Surface roughness was measured using an optical profilometer, hydrophobicity was measured via profilometry, and zeta potential was quantified using an electrokinetic analyzer. The ‘Celina’ cultivar exhibited the highest roughness, whereas ‘Williams’ had the lowest roughness. All the cultivars’ cuticles demonstrated hydrophilic characteristics, with contact angles ranging between 65° and 90°. For pH values exceeding 3.5, all pear surfaces exhibited a negative zeta potential. P. expansum growth was the slowest on the ‘Packham’s Triumph’ and ‘Conference’ cultivars. Treatment with trimethyl chitosan effectively inhibited P. expansum growth in the initial hours of incubation. In conclusion, diverse pear cultivars manifest distinct biophysical surface properties and varying susceptibility to P. expansum growth. The growth of P. expansum correlates positively with roughness, contact angle, and zeta potential. These differences can significantly impact shelf life potential and the overall postharvest quality of pears.

Comparative study and effects of urban green scape on the land surface temperature of a large metropolis and green city

Previous studies have provided valuable insights into the impact of green space (GS) on land surface temperature (LST). However, there is a need for in-depth comparative research on changing landscape patterns in cities and their effects on the urban thermal environment. This study investigates the spatial arrangement of GS and the influence of impervious surfaces on LST in urban areas, examining their cooling and warming effects in the urban landscapes of Beijing and Islamabad. The study aims to assess the impact of the spatial arrangement of GS on LST using a moving window of 1 km2 to analyze the overall effect of landscape patterns on the urban environment. Using Gaofen (GF–2) and Landsat–8 satellite data, we examined the biophysical surface properties of core urban areas. The results indicate a significant difference in the mean LST of 5.44 °C and 3.31 °C between impervious surfaces and GS in Beijing and Islamabad, respectively. The barren land and GS in Islamabad experience a higher LST of 3.39 °C compared to Beijing, which accounts for 1.39 °C. In Beijing, configuration metrics show no significant effect on urban LST, while edge density (ED) exhibits a slightly negative trend. In contrast, in the city of Islamabad, the landscape shape index (LSI), patch density (PD), and number of patches (NP) metrics have a significant influence on LST. The cooling effect of GS patches (0.1–0.5 ha) is more pronounced, while that of GS patches of 15–20 ha shows no significant effect on LST. The temperature difference (TD) of 5.01 °C was observed from the edge of GS in Beijing and 3.3 °C in Islamabad. Considering Islamabad's lush green scape compared to Beijing, this study suggests that Islamabad may experience an increase in LST in the future due to urbanization. This study's findings may assist urban policy-makers in designing sustainable green city layouts that effectively address future planning considerations.

Biophysical Characterization of Autochthonous and New Apple Cultivar Surfaces

Apples have long been known for their beneficial effects on human health due to the presence of various bioactive compounds. It is therefore very important to understand the biophysical properties of apple cuticle that dictate apples’ storability and quality. The purpose of this work was to determine the roughness, hydrophobicity, surface potential, and color of various autochthonous and new apple cultivars. The surface roughness was measured by optical profilometer, hydrophobicity by tensiometer, zeta potential by electro kinetic analyser, and surface color by chroma meter. Measurements reveal that the new cultivar Elstar has the roughest surface while the autochthonous cultivar Crown Prince Rudolph has the lowest roughness. Under normal physiological conditions, all apple surfaces were negatively charged, with Wax apple having the lowest and Crown Prince Rudolph the highest values; most cultivars had an isoelectric point at around pH = 3. The surfaces of the new cultivars were slightly more hydrophobic than those of the autochthonous. We conclude that autochthonous and new apple cultivars differ in biophysical surface properties, which might impact transpiration, bacterial/fungi adhesion and, consequently, apple storage and shelf life potential.

Study on the Effects of Landcover Changes on Surface Albedo and Surface Temperature in Bangladesh Using Remote Sensing and GIS

Dynamic changes in Earth’s land cover characteristics and associated temporally evolving biophysical surface properties, as well as their ultimate impacts on surface radiative (surface albedo) and climatic properties (land surface temperature), have been studied. The study area includes a part of southwestern Bangladesh covering a period of about twenty years from 1988 – 2011. The widely used Surface Energy Balance Algorithm for Land (SEBAL) has been applied in conjunction with satellite-derived radiative measurements. Relatively important land use types such as water, soil, sand, settlement, shrimp farm, forest and agricultural crop have been considered. Feature type conversion of parameters i.e Normalized Difference of Vegetation Index (NDVI), surface albedo and land surface temperature have been noticed over the area under the present study. The highest surface albedo as well as surface temperature value has been noticed over the sandy area. Analysis revealed increases of surface temperature by about 1 °C and 3 °C for land cover conversion from (i) crop to settlement and (ii) water to soil, respectively. All other categories of landcover conversion generally experience decreases in surface temperature. Spatial vegetation coverage and amount of soil moisture play a dominant role in the radiative as well as climatic properties.

The role of surface roughness, albedo, and Bowen ratio on ecosystem energy balance in the Eastern United States

Land cover and land use influence surface climate through differences in biophysical surface properties, including partitioning of sensible and latent heat (e.g., Bowen ratio), surface roughness, and albedo. Clusters of closely spaced eddy covariance towers (e.g., <10km) over a variety of land cover and land use types provide a unique opportunity to study the local effects of land cover and land use on surface temperature. We assess contributions albedo, energy redistribution due to differences in surface roughness and energy redistribution due to differences in the Bowen ratio using two eddy covariance tower clusters and the coupled (land-atmosphere) Variable-Resolution Community Earth System Model. Results suggest that surface roughness is the dominant biophysical factor contributing to differences in surface temperature between forested and deforested lands. Surface temperature of open land is cooler (−4.8°C to −0.05°C) than forest at night and warmer (+0.16°C to +8.2°C) during the day at northern and southern tower clusters throughout the year, consistent with modeled calculations. At annual timescales, the biophysical contributions of albedo and Bowen ratio have a negligible impact on surface temperature, however the higher albedo of snow-covered open land compared to forest leads to cooler winter surface temperatures over open lands (−0.4°C to −0.8°C). In both the models and observation, the difference in mid-day surface temperature calculated from the sum of the individual biophysical factors is greater than the difference in surface temperature calculated from radiative temperature and potential temperature. Differences in measured and modeled air temperature at the blending height, assumptions about independence of biophysical factors, and model biases in surface energy fluxes may contribute to daytime biases.

Vegetation, land surface brightness, and temperature dynamics after aspen forest die‐off

AbstractForest dynamics following drought‐induced tree mortality can affect regional climate through biophysical surface properties. These dynamics have not been well quantified, particularly at the regional scale, and are a large uncertainty in ecosystem‐climate feedback. We investigated regional biophysical characteristics through time (1995–2011) in drought‐impacted (2001–2003), trembling aspen (Populus tremuloides Michx.) forests by utilizing Landsat time series green and brown vegetation cover, surface brightness (total shortwave albedo), and daytime land surface temperature. We quantified the temporal dynamics and postdrought recovery of these characteristics for aspen forests experiencing severe drought‐induced mortality in the San Juan National Forest in southwestern Colorado, USA. We partitioned forests into three categories from healthy to severe mortality (Healthy, Intermediate, and Die‐off) by referring to field observations of aspen canopy mortality and live aboveground biomass losses. The vegetation cover of die‐off areas in 2011 (26.9% of the aspen forest) was significantly different compared to predrought conditions (decrease of 7.4% of the green vegetation cover and increase of 12.1% of the brown vegetation cover compared to 1999). The surface brightness of the study region 9 years after drought however was comparable to predrought estimates (12.7–13.7%). Postdrought brightness was potentially influenced by understory shrubs, since they became the top layer green canopies in disturbed sites from a satellite's point of view. Satellite evidence also showed that the differences of land surface temperature among the three groups increased substantially (≥45%) after drought, possibly due to the reduction of plant evapotranspiration in the Intermediate and Die‐off sites. Our results suggest that the mortality‐affected systems have not recovered in terms of the surface biophysical properties. We also find that the temporal dynamics of vegetation cover holds great potential for assessing propensity of subsequent mortality during drought itself, which could provide effective monitoring and potentially a much needed “early warning” of drought‐induced tree mortality.

A High-resolution Precipitation 2-step mapping Procedure (HiP2P): Development and application to a tropical mountainous area

Understanding the spatial and temporal variability of precipitation in tropical high mountain areas remains a key challenge. Point measurements are often not sufficient to capture the strong spatial variability particularly in mountain regions. Satellite remote sensing allows capturing the spatial heterogeneity of precipitation, yet it is generally characterized by significant bias. Rainfall satellite products such as those coming from the Tropical Rainfall Measuring Mission (TRMM) are being continuously improved and an increasing amount of high- and medium-resolution remote sensing data on biophysical surface properties is becoming available. Here we present a methodology that blends two TRMM products with remote sensing data on vegetation and topography to quantify the spatial distribution of precipitation in areas where direct observations are lacking. The approach assumes that vegetation cover, the topography and satellite-derived estimates of rainfall are reasonable indirect measures of ground-based precipitation. The methodology is evaluated for an area in the Andes of Ecuador. The results show that around 40% of the variance in weekly precipitation is explained by these proxies. During the drier periods of the year, vegetation is the strongest proxy. In the very wet areas and during the wet periods vegetation is usually in a climax development phase with no development trends to correlate with rain, and the other proxies dominate precipitation estimation. A cross-validation procedure in which each one of the weather stations is sequentially excluded from the analysis, was applied to test the performance of the methodology. The performance was satisfactory, and as expected it is related to the density of the weather station network and temporal rainfall variability. Overall we conclude that the methodology is useful for areas with very high variable conditions, where sufficient ground-data is available to establish the relationships with the different remote sensing datasets.

An Overview of Terra Mission Results Related to the Carbon Cycle

AbstractLaunched in December 1999 as the Earth Observing System's flagship observatory, the Terra Mission (formerly EOS AM‐1) carries a suite of five instruments that collect comprehensive global measurements of earth's atmosphere, cryosphere, lands, and oceans. One of the mission's science goals is the collection of data that will enable a better quantitative understanding of earth's carbon cycle through direct observation of atmospheric constituents and the provision of spatially explicit information about biophysical surface properties useful for modeling. In this article, highlights of the mission's use of five main instruments (ASTER, CERES, MISR, MODIS, and MOPITT) to address various aspects of the carbon cycle are reviewed, using examples of earth's photosynthetic production on land, vegetation structure and ecosystem response, and the extent and frequency of fires and their contribution of aerosols and carbon emissions to the atmosphere.

Pulmonary delivery of anti-contagion aerosol to diminish exhaled bioaerosols and airborne infectious disease

BACKGROUND/OBJECTIVES: Many contagious diseases are transmitted by exhalation of infectious droplets. Airborne infectious disease (AID) spread via exhaled bioaerosols (EBs) is a significant public health risk. Altering biophysical surface properties of airway lining fluid (ALF) through an inhaled, safe anticontagion aerosol (ACA) of isotonic saline provides a novel mechanism to diminish EB. In a recent study in normal volunteers (Edwards et al., PNAS 101:17383-388, 2004), half the study population was found to expire many more bioaerosol particles during quiet breathing and therefore bear the burden of production of EB. Administering nebulized isotonic saline (6 minutes) to these high producers diminished EB expired by 72.1 ± 8.2% for up to 6 hours. A subsequent study in Holstein bulls (a relevant animal model of AID) investigated the role of ACA dose on EB over time. METHODS: Seven Holstein bull calves (75-140 kg) were anesthetized, intubated, and maintained under general anesthesia following Defense Department and university-approved protocols on a custom-designed closed circle anesthesia system modified to evaluate pulmonary function and sample the number and size of EB using an Optical Particle Counter (Climet Instrument Company, Redlands, California). Every animal received four different ACA (0.9% isotonic saline) doses by nebulization (sham, 1.8, 6, or 12 minutes; Pari Respiratory Equipment, Starnberg, Germany) through the intubation tube; a minimum of 1week separated dosing in individual animals and doses were randomized throughout the study. EB were measured pre-ACA treatment and at 5, 15, 30, 60, 90, 120, and 180 minutes post-ACA treatment. RESULTS: Substantial inter-subject variability was found in baseline values, which revealed two distinct populations, low producers and high producers similar to the human trial. Delivery of ACA showed a dose-responsive effect on EB; 6 minutes of ACA treatment resulted in >50% decrement in EB for at least 120 minutes compared to pre-treatment. CONCLUSIONS: These results suggest individual variability in EB production may contribute to infectivity and ACA offers a dose-sensitive, ubiquitous measure to limit EB. A clinical trial assessing the role of AID (influenza) on EB production with a follow-up study evaluating the role of ACA in limiting EB is ongoing. These studies provide the foundation for a strategy to mitigate transmission of AID. This work was partially funded by the Technical Support Working Group (TSWG).

In vitro inhibition of biophysical surface properties and change in ultrastructures of exogenous pulmonary surfactant by albumin or fibrinogen.

In order to observe the effects of serum albumin and fibrinogen on biophysical surface properties and the morphology of pulmonary surfactant in vitro, we measured the surface adsorption rate, dynamic minimum and maximum surface tension (min-, max-ST) by Pulsating Bubble Surfactometer, and demonstrated ultrastructures on a series of mixtures with varying concentrations of albumin or fibrinogen and Surfactant-TA. The albumin and fibrinogen significantly inhibited the adsorption rate and ST-lowering properties of surfactant through increasing STs of adsorption rate, min-ST, and max-ST. The characteristic morphology of the Surfactant-TA changed from lamellar rod-like structure with open ends into spherical structures with loss of their open ends by mixing with albumin or fibrinogen. These inhibitory effects of albumin and fibrinogen on surface properties of surfactant were dependent upon the increasing concentration of albumin or fibrinogen. We concluded that albumin and fibrinogen significantly altered surfactant function and its ultrastructural morphology in vitro. These findings support the concept that albumin and fibrinogen-induced surfactant dysfunction may play an important role in the pathophysiology of adult respiratory distress syndrome, and this adverse effect of albumin and fibrinogen on surfactant might be overcome by administration of large doses of exogenous surfactant.

Pulmonary surfactant: an interdisciplinary approach.

Pulmonary surfactant research is considered from the perspective of interdisciplinary correlations based on information acquired from biophysics and physical chemistry, biochemistry, cell biology, physiology, and medicine. Current views of the important molecular constituents of the pulmonary surfactant system are described and related to the biophysical surface properties necessary to generate appropriate effects on respiratory physiology. The fundamental importance of multidisciplinary characterizations of lung surfactant, together with correlations between these descriptions, is stressed throughout. The primary advantage of such an approach is that it provides broad but coordinated principles and data with which to test hypotheses of lung surfactant function and roles in respiratory physiology and pathophysiology. This perspective is used to examine available information about the functional composition of lung surfactant, its surface tension-lowering properties at physiological temperature and humidity, and considerations relevant to the formulation of effective exogenous surface-active mixtures in the treatment of surfactant-deficient states. Also discussed is the biophysical state in vivo of pulmonary surfactant at the alveolar level, including current knowledge of the alveolar hypophase as well as the concept of functional surfactant acting in predominantly dry alveoli in the normal lung.