Quantitative Size Measurements Research Articles

Quantitative analysis of microplastics in beach sand via low-temperature solvent extraction and thermal degradation: Effects of particle size and sample depth

Quantifying trace levels of microplastics in complex environmental media remains a challenge. In this study, an approach combining field collection of samples from different depths, sample size fractionation, and plastic quantification via pyrolysis-gas chromatography–mass spectrometry (Py-GC–MS) was employed to identify and quantify microplastics at two public beaches along the northeast coast of the U.S. (Salisbury beach, MA and Hampton beach, NH). A simple sampling tool was used to collect beach sand from depth intervals of 0–5 cm and 5–10 cm, respectively. The samples were sieved to give three size fractions: coarse (>1.2 mm), intermediate (100 μm–1.2 mm), and fine (1.2 μm–100 μm) particles. Following density separation and wet peroxide oxidation, a low-temperature solvent extraction protocol involving 2-chlorophenol was used to extract polyester (PET), polystyrene (PS), polyamide (PA), and polyvinyl chloride (PVC). The extract was analyzed using Py-GC–MS for the respective polymers, while the solid residue was pyrolyzed separately for polyethylene (PE) and polypropylene (PP). The one-step solvent extraction method significantly simplified the sample matrix and improved the sensitivity of analysis. Among the samples, PET was detected in greater quantities in the fine fraction than in the intermediate size fraction, and PET fine particles were located predominantly in the surface sand. Similar to PET, PS was detected at higher mass concentrations in the fine particles in most samples. These results underscore the importance of beach environment for plastic fragmentation, where a combination of factors including UV irradiation, mechanical abrasion, and water exposure promote plastic breakdown. Surface accumulation of fine plastic particles may also be attributed to transport of microplastics through wind and tides. The proposed sample treatment and analysis methods may allow sensitive and quantitative measurements of size or depth-related distribution patterns of microplastics in complex environmental media.

Quantitative photography for rapid, reliable measurement of marine macro‐plastic pollution

Abstract Plastics are now ubiquitous in the environment and have been studied in wildlife and in ecosystems for more than 50 years. Measurement of size, shape and colour data for individual fragments of plastic is labour‐intensive, unreliable and prone to observer bias, particularly when it comes to assessment of colour, which relies on arbitrary and inconsistently defined colour categorisations. There is a clear need for a standard method for data collection on plastic pollution, particularly one that can be readily automated given the number of samples involved. This study describes a new method for standardised photography of marine plastics in the 1–100 mm size range (meso‐ and macro‐plastics), including colour correction to account for any image‐to‐image variation in lighting that may impact colour reproduction or apparent brightness. Automated image analysis is then applied to detect individual fragments of plastic for quantitative measurement of size, shape, and colour. The method was tested on 3793 fragments of debris ingested by Flesh‐footed Shearwaters (Ardenna carneipes) on Lord Howe Island, Australia, and compare results from photos taken in two separate locations using different equipment. Photos were acquired of up to 250 fragments at a time with a spatial resolution of 70 μm/pixel and were colour‐corrected using a reference chart to ensure accurate reproduction of colour. The automated image analysis pipeline was found to have a 98% success rate at detecting fragments, and the different size and shape parameters that can be outputted by the pipeline were compared in terms of usefulness. The evidence shown in this study should strongly encourage the uptake of this method for cataloguing macro‐scale plastic pollution, as it provides substantially higher quality data with accurate, reliable measurements of size, shape and colour for individual plastics that can be readily compared between disparate datasets.

Measurement Reliability and Diagnostic Accuracy of Virtual Monoenergetic Dual-Energy CT in Patients with Colorectal Liver Metastases

To compare dual-energy CT virtual monoenergetic images (VMI) and standard reconstructions for reliability of quantitative size measurements and diagnostic accuracy for the detection of colorectal liver metastases (CRLM). We retrospectively included 98 patients (mean age, 61.1±11.5 years) with colorectal cancer, of whom 49 subjects had CRLM. All patients underwent a portal-venous phase dual-energy CT examination. Standard linearly-blended reformats and 40-keV VMI were reconstructed. For both reconstruction techniques, two blinded readers performed measurements of CRLM twice in a preset sequence. Three additional radiologists independently assessed all liver lesions in terms of dignity (benign vs. malignant). Sensitivity, specificity and diagnostic accuracy were calculated on a per-patient basis using MRI as reference standard. Readers scored the suitability for metric measurements and their diagnostic confidence using 5-point Likert scales. Inter-rater agreement was evaluated using intraclass correlation coefficient (ICC). Inter-rater agreement for lesion size measurements was higher for 40-keV VMI (ICC, 0.88) compared to standard linearly-blended series (ICC, 0.80). Sensitivity and diagnostic accuracy for the detection of CRLM were significantly higher for VMI at 40-keV compared to standard reconstructions (90.6% vs. 80.6%, and 89.1% vs. 81.3%; p < 0.001). Reader scores indicated that 40-keV VMI were more suitable for metric lesion measurements and provided greater diagnostic confidence compared to standard reformats (median, 5 vs. 3, and 5 vs. 4; both p < 0.001). Low-keV VMI reconstructions improve reliability of quantitative size measurements and diagnostic accuracy for the assessment of CRLM compared to standard linearly-blended images.

Size measurement of Daphnia pulex using low-coherence Gabor digital holography

We measured the size of Daphnia pulex (D. pulex), which is an indicator organism used for examining toxicity, under freely-swimming and stress-free conditions, made possible by the post-focusing ability of digital holography (DH). This environmental measurement is a new application of DH. This implementation, which is a key point of this research, should be applicable to real on-site use in non-sterile and unstable mechanical situations. Through trial and error, we arrived at the simplest interferometer configuration using a single beam line that can withstand vibrations, a low-coherence light source for reducing coherent noise, and single-shot image capturing. Automatic size measurement based on DH with image processing was performed. The originality of this research is the quantitative size measurement and performance estimation achieved by comparing the results with those from conventional manual eye measurement using ordinary optical microscope observation and image processing software. The estimation also allowed us to determine the proper parameters in the image processing for DH measurement.

Automated quality assessment of cocoons using a smart camera based system

In this paper, the development of a novel quality assessment system for Bombyx mori L. cocoons is presented, which offers significant advantages over the conventional manual method (subjective, tests only few sample cocoons, involves health hazards) in terms of labor friendliness, accuracy, speed and running cost. This system consisted of a conditioned illumination unit, image acquisition and processing unit realized with a smart camera. The camera acquired the images of cocoons and by image processing algorithms (morphological operation, image enhancement, and ellipse fitting), quantitative measurements of size, shape and stain color were accomplished and automatically classified each cocoon into four defective categories and good cocoons. The system not only highlighted each category on camera screen but also displayed statistical information such as counts of cocoons in each category and overall defect percentage. In addition to that, the system was programmed to alert the user when the defect percentage exceeded a particular threshold value. The results showed that the system was capable of assessing 96 cocoons per second acquired within a single frame. It showed 100% accuracy on a sample size of 137 cocoons. To expose whole cocoon surface, they were rolled over a slope at a speed of eight rotations per second, while the system captured and processed the video of the whole surface. This process enabled in meeting the same level of quality assessment standard and counting accuracy as that of manually exposing the defective areas to the field of view when acquired in a single image.

Sea spray aerosol chemical composition: elemental and molecular mimics for laboratory studies of heterogeneous and multiphase reactions.

Sea spray aerosol particles (SSA), formed through wave breaking at the ocean surface, contribute to natural aerosol particle concentrations in remote regions of Earth's atmosphere, and alter the direct and indirect effects of aerosol particles on Earth's radiation budget. In addition, sea spray aerosol serves as suspended surface area that can catalyze trace gas reactions. It has been shown repeatedly that sea spray aerosol is heavily enriched in organic material compared to the surface ocean. The selective enrichment of organic material complicates the selection of representative molecular mimics of SSA for laboratory or computational studies. In this review, we first provide a short introduction to SSA formation processes and discuss chemical transformations of SSA that occur in polluted coastal regions and remote pristine air. We then focus on existing literature of the chemical composition of nascent SSA generated in controlled laboratory experiments and field investigations. We combine the evidence on the chemical properties of nascent SSA with literature measurements of SSA water uptake to assess SSA molecular composition and liquid water content. Efforts to speciate SSA organic material into molecular classes and specific molecules have led to the identification of saccharides, alkanes, free fatty acids, anionic surfactants, dicarboxylic acids, amino acids, proteinaceous matter, and other large macromolecules. However to date, less than 25% of the organic mass of nascent SSA has been quantified at a molecular level. As discussed here, quantitative measurements of size resolved elemental ratios, combined with determinations of water uptake properties, provides unique insight on the concentration of ions within SSA as a function of particle size, pointing to a controlling role for relative humidity and the hygroscopicity of SSA organic material at small particle diameters.

Quantitative Measurements of the Size Scaling of Linear and Circular DNA in Nanofluidic Slitlike Confinement

Quantitative size measurements of single linear and circular DNA molecules in nanofluidic slitlike confinement are reported. A novel experimental method using DNA entropophoresis down a nanofluidic staircase implemented comprehensive variation of slitlike confinement around d ≈ 2p, where d is the slit depth and p is the persistence length, throughout the transition from strong to moderate confinement. A new numerical analysis approximated and corrected systematic imaging errors. Together, these advances enabled the first measurement of an experimental scaling relation between the in-plane radius of gyration, R∥, and d, yielding R∥ ∼ d–1/6 for all DNA samples investigated. This differs from the theoretical scaling relation, Re ∼ d–1/4, for the root-mean-square end-to-end size, Re. The use of different labeling ratios also allowed a new test of the influence of fluorescent labels on DNA persistence length. These results improve understanding of the basic physical behavior of polymers confined to nanofluidic slits and inform the design of nanofluidic technology for practical applications.

Morphology and state of mixture of atmospheric soot aggregates during the winter season over Southern Asia-a quantitative approach

The atmospheric brown cloud phenomena characterized by a high content of soot and a large impact on the solar radiative heating especially affects the tropical Indian Ocean during the winter season. The present study focuses on morphological characteristics and state of mixture of soot aggregates during the winter season over India. Given are quantitative measures of size, morphology and texture on aggregates collected in air at two different sites: Sinhagad near Pune in India and Hanimaadhoo in Maldives. For the latter site two different synoptic patterns prevailed: advection of air from the Arabian region and from the Indian subcontinent, respectively.Aggregates collected at Sinhagad, were associated with open branched structures, characteristic of fresh emission and diameters between 220 and 460 nm. The Hanimaadhoo aggregates were associated with aged closed structures, smaller sizes (130-360 nm) and frequently contained inorganic inclusions. Those arriving from the Indian subcontinent were characterized by the presence of an additional organic layer that covered the aggregate structure. These organic coatings might be a reasonable explanation of the low average wash-out ratios of soot two to seven times lower than that of nss-SO42- that have been reported for air flow arriving at Hanimaadhoo from the Indian subcontinent in winter.

Quantitative measurement of size and three-dimensional position of fast-moving bubbles in air-water mixture flows using digital holography

We present a digital in-line holographic imaging system for measuring the size and three-dimensional position of fast-moving bubbles in air-water mixture flows. The captured holograms are numerically processed by performing a two-dimensional projection followed by local depth estimation to quickly and efficiently obtain the size and position information of multiple bubbles simultaneously. Statistical analysis on measured bubble size distributions shows that they follow lognormal or gamma distributions.

Brief communication: Methods of sequence heterochrony for describing modular developmental changes in human evolution

Interest in the developmental changes leading to apomorphic features of human anatomy is longstanding. Although most research has focused on quantitative measures of size and shape, additional information may be available in the sequence of events in development, including aspects of phenotypic integration. I apply two recently proposed techniques for analyzing developmental sequences to literature data on human and chimpanzee age of limb element ossification center appearance in radiographs. The event-pair cracking method of Jeffery et al. (Syst Biol 51 [2002] 478-491) offers little additional insight on sequence differences in this data set than a simpler difference of ranks. Both reveal shifts in timing that are likely related to locomotor differences between the two species. Poe's (Evolution 58 [2004] 1852-1855) test for modularity in a sequence identifies the ankle, wrist, and hind limb as developmental modules, which may correspond to localized combinations of developmental genes. Ossification patterns of the rays of the hand and foot show little modularity. Integrating these and other methods of sequence analysis with traditional metrics of size and shape remains an underdeveloped area of inquiry.

2834 熱応答スペクトロスコピー逆問題解析手法を用いた減肉欠陥同定法の開発(S37-3 非破壊評価とモニタリング(3),S37 非破壊評価とモニタリング)

An inverse analysis method for the thermal response spectroscopy is proposed for quantitative measurement of size and depth of the defects. Sequential thermal response data observed on the surface of objective body under active step heating were processed by lock-in analysis scheme based on the Fourier series expansion. Fourier coefficients synchronizing with sine and cosine waves were calculated, and they are represented in spectroscopic diagram. Fourier coefficients data of certain defect depth and size obtained for various thermal fluctuation periods showed characteristic curves in the spectroscopic diagram. In this study, least residual inverse analysis scheme was applied to the defect parameter determination based on the Fourier coefficient values in the spectroscopic diagram.

Characterization of the metal particles fraction in ceramic matrix composites fabricated under high pressure

This paper presents preliminary results concerning Al 2O 3–Ni composites fabricated by sintering under a high pressure of 7.7 GPa, at a temperature below the melting temperature of nickel. The microstructure of composites was characterized by scanning and transmission electron microscopy. Quantitative measurements of size, shape and distribution of metal particles were based on image analysis. A correlation between the size of the Ni particles and their location has been found. Small Ni particles, with a grain size in the range of 50–500 nm, are mostly located inside the ceramic grains. Some Ni particles are also situated at the grain boundaries, and large particles are surrounded by ceramic grains. The shape of the ceramic grains suggests that the ceramic powder particles underwent deformation during the process of consolidation under high pressure.

Quantitative measures for shape and size of particles

Previous efforts to define these terms are reviewed and their deficiencies noted. New quantitative measures of size and shape are proposed, based upon measurements made possible by image analysis techniques. These may be applied to both single particle and to assemblages of particles. Laboratory test results are presented to demonstrate the application of one of the new measures. Suggestions are made for further research.

Application of size exclusion chromatography with surfactant eluent to the study of polymer–surfactant interactions: oligomeric and micellar chromatographic effects

Complexation of sodium dodecyl sulphate (SDS) with a wide range of molecular weights of poly(ethylene glycol) (PEG) and poly(ethylene oxide) (PEO) has been studied by size exclusion chromatography using aqueous SDS eluent. A multi-angle laser light scattering detector and a differential refractometer were applied to give direct measurement of the molecular weight of complexes without reference to elution volume, since the latter is not a reliable indicator of the complex size. Background light scattering from micellar eluents hampered quantitative size measurements, but was minimal in sub-micellar eluent, where saturated binding was observed for polymers larger than 1000 g mol −1. Multiple peaks and voids were observed in the elution profiles of low molecular weight polymers (up to a mass of 600 g mol −1) in eluent at micellar concentrations. Several sources contribute to this behavior, including micellar chromatographic separation of the PEG oligomers due to their different distribution coefficients between the micellar and water phases. Preliminary results are reported for distribution coefficients of individual oligomers in a 600 g mol −1 PEG sample. Three distinct binding behaviors are observed with increasing degree of polymerization of PEG: no interaction for small glycols, equilibrium partitioning of intermediate oligomers in and out of micelles, and binding of micelles to the larger polymers.

Body form and skeletal morphometrics during larval development of the sea urchin Lytechinus variegatus Lamarck

Development of the echinopluteus of the subtropical/tropical sea urchin Lytechinus variegatus Lamarck, was studied using quantitative measures of size, shape, and the growth of the larval body and skeleton. Larvae of L. variegatus developed rapidly, attaining metamorphic competence in 9–10 days (depending on diet) at a culture temperature of 26°C. Larvae grew substantially from the initial 2-arm pluteus stage to the fully developed eight-arm pluteus with a juvenile rudiment. Larval length increased 2.8-fold, total arm length (summed over all larval arm pairs) increased 7.3-fold. Ciliated band length (an index of feeding capability) increased 6.8-fold, 76% of the increase was allometric, i.e., due to shape change. An index of shape, the ratio of ciliated band length: body length increased 2.8-fold during development to a maximum value of 13.87. Allometric growth occurred both during the period of arm formation and later during rudiment formation by disproportionate growth of the larval arms. The echinopluteus skeleton of Lytechinus variegatus consists of six separate elements: 2 sets of paired (left and right) elements, the body-postoral-anterolateral rod complex and the posterodorsal rods; and 2 unpaired elements, the dorsal arch and the posterior transverse rod. The skeleton of the main body region (body rods) did not grow after the formation of the initial 2-arm larval stage. Body length and arm length increases were due entirely to elongation of the arm skeleton. Increases in larval circumference and development of various lobes were supported by elongation of the dorsal and ventral transverse rods. Pedicellariae (1–3) developed around day 7 at the posterior of the larva. Juvenile skeletal plates developed in association with the proximal tips of several larval skeletal rods, such as the base of the dorsal arch and the bases of the posterodorsal rods. There are several common features of pluteus larval growth that are shared among species, with different egg sizes, from different orders, and from different geographic regions. The most important similarity is the scaling of feeding structures (ciliated band length) relative to larval body size. Elaboration of the ciliated band is by growth of the larval arms with 60–70% of the band located on the arms. However, there are differences in which arm pairs contribute most to form change and feeding capability. These descriptions and comparisons suggest both similarities and differences in larval growth and form that are functionally important and deserve greater attention from larval ecologists.

STEM-based mass spectroscopy of supported Re clusters

Annular dark-field imaging in a scanning transmission electron microscope (STEM) is known to enhance contrast of small supported particles of heavy elements. At high scattering angles (∼ 100 mrad), this imaging technique can be used quantitatively to measure absolute particle size by comparing measured and theoretical elastic scattering cross-sections. Here, we report quantitative size measurement of small rhenium particles supported on thin graphite films. Statistical measurement of absolute cross-sections of prepared Re-6 clusters show good agreement with theoretical cross-sections, within a ±2 atom random experimental error. This is the first report of such measurements using angles sufficiently high that coherent effects can be neglected. Our experiments confirm the exceptional stability of the Re-6 organometallic compound relative to other compounds with 7, and 8-Re atoms. Details of the high angle annular dark-field STEM experiments are presented including image processing/analysis, annular dark-field detector calibration, and sources of error in the absolute intensity measurements. We discuss the future possibility of individual atomic sensititity.

Snow crystal imaging using scanning electron microscopy: I. Precipitated snow

Abstract Low-temperature scanning electron microscopy (SEM) was used to observe precipitated snow crystals. The newly-fallen snow crystals were obtained in storms at Beltsville, Maryland, and at Bearden Mountain near Davis, West Virginia, USA. The snow samples were mounted on modified SEM stubs, frozen in liquid nitrogen, sputter coated with platinum, and imaged with an electron beam. Many types of precipitated snow crystals were observed including hexagonal plates, columns, needles, stellar dendrites, bullets, graupel, and rimed crystals. The SEM techniques that were developed can be used for quantitative measurements of size, shape and structure of crystals. SEM of precipitated snow appears to have direct application for the inference of atmospheric and cloud conditions where the snow crystals formed and travelled to the ground and for the development of a relationship between snow crystal type and snowfall intensity and amount. The SEM technique provides a new procedure to record permanently snow cryst...

G7 - New 3-dimensional (3-D) ultrasound method for the quantitative measurement of size and volume of soft plaques in superficial large arteries

G7 - New 3-dimensional (3-D) ultrasound method for the quantitative measurement of size and volume of soft plaques in superficial large arteries

Acoustic Quantification of Left Ventricular Volumes and Function in Children With Congenital and Acquired Heart Disease

Automated acoustic quantification (AQ) technique for left ventricular (LV) volume and function has been validated in vitro and in adults. Its reliability and applicability in children has not been validated. Therefore, 30 children with different forms of congenital and acquired heart disease underwent cineangiography followed by AQ for LV volumes and ejection fraction measurements. Their median age was 3.6 years and median weight was 14 kg. In all patients, AQ was obtained without difficulty; the quality was adequate in all but the largest patient. The mean LV end‐diastolic volume by cineangiography was 66 mL compared with 47 mL by AQ; there was good correlation between the two techniques with an r = 0.92, P &lt; 0.001. The mean LV end‐systolic volume was 24 mL by cineangiography compared to 19 mL by AQ, with good correlation, r = 0.94, P &lt; 0.001. The median ejection fraction by cineangiography was 63% compared to 63.5% by AQ. However, the correlation was not strong, r = 0.52, most likely due to lack of wide range of ejection fractions. In conclusion, AQ yielded quantitative measurements of size and function in normal and abnormal shaped ventricles as reliable as cineangiography and could be used to follow LV quantitatively in patients in whom accurate assessment is essential.

Size distributions in two porous chondritic micrometeorites

Quantitative size measurements of granular units [GUs], and nanometer-sized minerals in these units, in two porous chondritic micrometeorites are investigated for the information that they carry on the processes in the early solar system. The matrix of these micrometeorites consist of loosely packed, 0.1 μm-sized, GUs. These objects were a major component of the solar nebula dust that accreted into protoplanets. The matrix in micrometeorite W7010 *A2 has a fractal dimension with a small coefficient, D = 0.83, that supports efficient sticking of carbon-rich GUs during accretion. The fractal nature of the matrix provides a way to calculate the density using the aggregate size. The resulting very low density for porous chondritic micrometeorites is 0.08–0.14 g cm −3, which supports the view that they are the solid debris from unconsolidated solar system bodies (e.g., comet nuclei, or regolith deposits on carbon-rich asteroids). Chondritic GUs contain ultrafine olivines, pyroxenes, and sulfides, embedded in hydrocarbons and amorphous carbons. Nanocrystals in the micrometeorites W7010 *A2 and U2015 *B show log normal size distributions. The high incidence of disk-shaped grains, a changeover from disk-shaped to euhedral grains, the unevolved nature of the size distributions, and multiple populations for grains < 127 nm in size, are consistent with continuous post-accretion nucleation and growth in amorphous GUs, including coarsening via Ostwald ripening.