Size Sorting Research Articles

Retrieving Estimates of the Storm‐Relative Wind Profile From the Vertical Variation of Hydrometeor Size Sorting Signatures

AbstractRaindrop fall speed increases with raindrop size. Because larger raindrops fall through a given layer of the atmosphere more quickly compared to smaller raindrops, they spend less time in the layer and, therefore, have less time to be acted on and advected by the storm‐relative winds. This results in hydrometeor size sorting which impacts the polarimetric radar variables such as differential reflectivity and specific differential phase . Previous work has shown a strong correlation between the mean storm‐relative wind in the sorting layer and the separation between regions of enhanced and at the bottom of the sorting layer. This study leverages this finding, along with a simple size sorting model, to construct radar‐derived estimates of the storm‐relative wind profile. The radar‐derived “pseudo‐hodographs” are well‐correlated with the magnitude and direction of the corresponding storm‐relative wind profiles. Further, these radar‐derived estimates of the storm‐relative winds are used to calculate estimates of shear and storm‐relative helicity, which also exhibit a strong correlation.

Evolution process of chemical weathering and sediment sources in the Makran Continental margin since the Younger Dryas

The chemical weathering processes and sedimentary source evolution since the Younger Dryas (YD) in the low-latitude arid continental margin have been investigated. Two sediment cores, MK07G and MK09G, were retrieved from the Makran continental margin in the northern Arabian Sea and subjected to analyses of major and trace elements, along with AMS14C dating. The results show that since the YD, the weathered parent rocks of Makran sediments have remained relatively stable, predominantly consisting of felsic rocks, with some contributions from mafic rocks. The Makran sediments exhibit initial to moderate weathering, with no discernible effects from grain size sorting or disturbances from sediment recycling, indicating primary deposition. Significant contributions of terrigenous eolian dust from surrounding continents (e.g., the Indian subcontinent, Arabian Peninsula, and northeastern Africa) were identified, along with riverine inputs from the Dasht River and fine-grained components from the Late Pleistocene Indus delta sediment, as well as proximal basin sedimentation. The evolution of sediment sources in the study area is significantly influenced by the Indian Monsoon and westerly wind systems, with intensified monsoon phases and westerly conditions correlating with increased fluvial input. Furthermore, chemical weathering processes since the YD are closely linked to local precipitation patterns, where intensified rainfall enhances weathering intensity. Records from the Makran continental margin indicate a teleconnection between chemical weathering and sedimentary processes in the Arabian Sea and Bond events in the North Atlantic, highlighting the extensive influence of Northern Hemisphere climate fluctuations.

Label-Free Microfluidic Apheresis of Circulating Tumor Cell Clusters.

Screening liters of blood (i.e., apheresis) represents a generalized approach to promote the reliable access to circulating tumor cell clusters (CTCCs), which are known to be highly metastasis-competent, yet ultrarare. However, no existing CTCC sorting technology has demonstrated high throughput, high yield, low shear stress, and minimal blood dilution simultaneously as required in apheresis. Here, a label-free method is introduced termed Precision Apheresis for Non-invasive Debulking of cell Aggregates (PANDA) to continuously isolate CTCCs from undiluted blood to clean buffer through size sorting, processing 1.4 billion cells per second. The cell focusing is optimized within whole blood leveraging secondary transverse flow and margination. The PANDA chip recovers >90% of spiked ≈24 rare HeLa cell clusters from 100mL undiluted blood samples (equivalent to ≈500 billion blood cells) at 1 Lh-1 throughput, with ≤20s device residence time, ≤15Pa shear stress, and >99.9% return of blood components. The technology lays the groundwork for future routine isolation to increase the recovery of these ultrarare yet clinically significant tumor cell populations from large volumes of blood to advance cancer research, early detection, and treatment.

Development of novel prototype of orange sorting machine

Orange is one of the most popular fruits in the world. Oranges originate from Southeast Asia, India, and southern China. Nowadays, they are grown in warm regions around the world. Oranges are consumed either fresh or in the form of fruit juice. Depending on the type of orange, when ripe, its surface is orange or green, with a sweet or slightly sour taste. In Vietnam, oranges have significant export value. Therefore, ensuring consistent quality of oranges before export is an important requirement. Currently in Vietnam, this process is done manually or semi-automatically, resulting in low productivity and inadequate output for export purposes. This article introduces a new design of an automatic orange sorting machine. The proposed machine is equipped with functions to classify the size and defects on the orange surface through image processing technique. The experiment results show that the proposed machine works effectively. The size sorting module worked perfectly with absolute accuracy while the image processing module ensures the confidence level of 95%. The proposed machine could replace the manual sorting process with high accuracy.

Photometric Properties within the Reiner Gamma Swirl: Constraining Formation Mechanisms

The area in the Reiner Gamma swirl studied by Weirich et al. for topographic correlations also displays correlations with the Hapke-model-derived single-scattering albedo, surface roughness, and particle scattering properties with swirl unit. The correlations with single-scattering albedo associate compositional variations in plagioclase and FeO content with swirl unit. The correlations with photometric surface roughness show a rougher surface on-swirl, implying a potentially more porous surface on-swirl compared to off-swirl. This suggests the variations in single-scattering albedo are dominated by the compositional differences and not structural differences, such as compaction. Grain-size differences could still contribute to the albedo variations. Differences in particle scattering properties between on-swirl and off-swirl are counter-indicative of the trend expected from variations in space weathering, unless there is a process to initiate either size sorting or compositional differences. The photometric properties point to a complex interaction of multiple processes to form the swirl units, not a singular dominant process. Variations in weathering, dust mobilization and entrapment, and impact modification may all play a key role.

ZDR Backwards Arc: Evidence of Multi‐Directional Size Sorting in the Storm Producing 201.9 mm Hourly Rainfall

AbstractIn this study, we present radar polarimetric characterizations of the storm producing 201.9 mm hourly rainfall on 20 July 2021 in Zhengzhou, China. We employed the separation signatures of enhanced polarimetric observations to investigate hydrometeor size sorting processes, and developed an algorithm to quantify the size sorting directions. Analysis of coupled polarimetric observations unraveled multi‐directional size sorting (MSS) occurred as a low‐level differential reflectivity ZDR backwards arc signature encompassing the rainfall center during the most intensive rainfall period. The rainfall intensification is in step with the increase of size sorting directions. Model simulations with two‐moment microphysics scheme suggest that the presence of arc‐shaped updrafts is conducive to MSS and increased rain rates around the rainfall center. This work sheds novel insights into the kinematics‐driven microphysics in extreme rainfall storms, warranting the potential of using coupled polarimetric signatures for warning catastrophic extreme rainfall events.

Higher water content observed in smaller size fraction of Chang'e-5 lunar regolith samples

Water has been detected in lunar regolith, with multiple sources identified through the analysis of individual grains. However, the primary origin of water in the bulk lunar regolith remains uncertain. This study presents spectroscopic analyses of water content in sealed Chang'e-5 samples. These samples were sieved into various size fractions (bulk, <45 μm, and 45–355 μm) inside a glovebox filled with high-purity nitrogen. Results indicate a higher water content in the fine fractions (∼87 ± 11.9 ppm) than in bulk soil (∼37 ± 4.8 ppm) and coarse fractions (∼11 ± 1.5 ppm). This suggests that water is predominantly concentrated in the outermost rims of the regolith grains, and thus exhibits dependence on the surface volume ratio (also known as surface correlation), indicating solar wind is a primary source of lunar surface water. Laboratory, in-situ, and orbital results bridge sample analysis and remote sensing, offering a cohesive understanding of lunar surface water characteristics as represented by Chang'e-5. The discovery provides statistical evidence for the origin of water in lunar soil and can be considered representative of the lunar surface conditions. The water enrichment of the finest fraction suggests the feasibility of employing size sorting of lunar soils as a potential technological approach for water resource extraction in future lunar research stations.

Granular Hydrogels Improve Myogenic Invasion and Repair after Volumetric Muscle Loss.

Skeletal muscle injuries including volumetric muscle loss (VML) lead to excessive tissue scarring and permanent functional disability. Despite its high prevalence, there is currently no effective treatment for VML. Bioengineering interventions such as biomaterials that fill the VML defect to support cell and tissue growth are a promising therapeutic strategy. However, traditional biomaterials developed for this purpose lack the pore features needed to support cell infiltration. The present study investigates for the first time, the impact of granular hydrogels on muscle repair - hypothesizing that their flowability will permit conformable filling of the defect site and their inherent porosity will support the invasion of native myogenic cells, leading to effective muscle repair. Small and large microparticle fragments are prepared from photocurable hyaluronic acid polymer via extrusion fragmentation and facile size sorting. In assembled granular hydrogels, particle size and degree of packing significantly influence pore features, rheological behavior, and injectability. Using a mouse model of VML, it is demonstrated that, in contrast to bulk hydrogels, granular hydrogels support early-stage (satellite cell invasion) and late-stage (myofiber regeneration) muscle repair processes. Together, these results highlight the promising potential of injectable and porous granular hydrogels in supporting endogenous repair after severe muscle injury.

Study of Microphysical Signatures Based on Spectral Polarimetry during the RELAMPAGO Field Experiment in Argentina

Abstract Weather radars with dual-polarization capabilities enable the study of various characteristics of hydrometeors, including their size, shape, and orientation. Radar polarimetric measurements, coupled with Doppler information, allow for analysis in the spectral domain. This analysis can be leveraged to reveal valuable insight into the microphysics and kinematics of hydrometeors in precipitation systems. This paper uses spectral polarimetry to investigate precipitation microphysics and kinematics in storm environments observed during the Remote Sensing of Electrification, Lightning, and Mesoscale/Microscale Processes with Adaptive Ground Observations (RELAMPAGO) field experiment in Argentina. This study uses range–height indicator scan measurements from a C-band polarimetric Doppler weather radar deployed during the field campaign. In this work, the impact of storm dynamics on hydrometeors is studied, including the size sorting of hydrometeors due to vertical wind shear. In addition, particle microphysical processes because of aggregation and growth of ice crystals in anvil clouds, as well as graupel formation resulting from the riming of ice crystals and dendrites, are also analyzed here. The presence of different particle size distributions because of the mixing of hydrometeors in a sheared environment and resulting size sorting has been reported using spectral differential reflectivity (sZdr) slope. Spectral reflectivity sZh and sZdr have also been used to understand the signature of ice crystal aggregation in an anvil cloud. The regions of pristine ice crystals are identified from vertical profiles of spectral polarimetric variables in anvil cloud because of sZh &lt; 0 dB and sZdr values around 2 dB. It is also found that the growth process of these ice crystals causes a skewed bimodal sZh spectrum due to the presence of both pristine ice crystals and dry snow. Next, graupel formation due to riming has been studied, and it is found that the riming process produces sZh values of about 10 dB and corresponding sZdr values of 1 dB. This positive sZdr indicates the presence of needle/columnar secondary ice particles formed by ice multiplication processes in the riming zones. Last, the temporal evolution of a storm is investigated by analyzing changes in hydrometeor types with time and their influence on the spectral polarimetric variables.

A microparticle manipulation method facilitated via microfluidic chip based on swirling flow topology design and its application in sorting

Microfluidics technology is trustworthy for microparticle operation as it doesn't involve destructive contact. Our research endeavors have encompassed microparticles manipulation by generating swirling flow region (SFR). Now we try to utilize swirl and flow topology to promote microfluidic chip design because serial operation is still not well enabled. Herein, a new model is proposed for a 6-microchannel microfluidic chip, which has realized active control of microparticles. The chip is capable of trapping, transferring, and enriching microparticles, and is applied for microparticles sorting. Simulation is performed to substantiate the viability of generating SFRs, and experiments are conducted on 3D-printed chips to validate the envisioned functions of the proposed microfluidic chip. Encouragingly, our experiments yield convincing outcomes, wherein microparticles are successfully trapped, transferred, and enriched in separated SFRs. With the help of a self-developed vision algorithm, the size sorting of microparticles is facilitated. Significantly, the manipulation of different microparticles can be achieved by tuning the microchannel velocities and tailoring the flow topology. This work presents a pioneering flow field structure and provides a feasible scheme for sorting microparticles, which is a noteworthy advance in swirl-based microfluidic chip applications. It is a potential mean for bio-/chemical analysis and fluidic-directed assembly of multiple microparticles.

Impact of particle size separation on the stabilisation efficiency of heavy-metal-contaminated soil: a meta-analysis.

The separation of heavy-metal-contaminated soil by particle size is crucial for minimising the volume of contaminated soil because of the pronounced variability in the heavy-metal distribution among different soil particle sizes. However, relevant analyses on the effect of soil particle size sorting on stabilisation are limited. Therefore, we screened 2766 peer-reviewed papers published from January 2010 to April 2022 in the Web of Science database, of which 117 met the screening requirements, and conducted a meta-analysis to explore how soil particle size sorting and the interaction between sorting particle size and soil properties affect the stabilisation of heavy metals. The results showed that: (1) For fractionations ≤0.15 mm and from 0.15-2 mm, the materials demonstrating the highest average unit stabilisation efficiency were phosphate (45.0%/%) and organic matter (59.5%/%), respectively. (2) The smaller the size of soil particles, the greater the effect of the initial pH on stabilisation efficiency. (3) Similarly, for soil organic matter, smaller particle sizes (≤0.15 mm) combined with a lower initial content (≤1%) significantly increased the heavy metal stabilisation efficiency. (4) The impact of soil particle size fractionation on unit stabilisation efficiency was observed to be similar for typical heavy metals, specifically Cd and Pb. The relationship between particle size and unit stabilisation efficiency shows an inverted U shape. Particle size sorting can affect the distribution of heavy metals, but the type of stabilisation agent should also be considered in combination with the soil properties and heavy metal types.

Sub-wavelength focused light and optical trapping application based on two-mode interference from an optical micro-/nanofiber

The ability to focus light on a subwavelength scale is essential in modern photonics. Optical microfiber-based sub-wavelength focusing will allow a miniaturized, flexible and versatile tool for many applications such as biomedical imaging and optomechanics. For a separate mode exited from an optical micro-/nanofiber endface, the photons will experience significant diffraction into the free space. This situation can be changed by incorporating two-mode interference along with the specific spatial distributions of both &lt;i&gt; &lt;b&gt;E&lt;/b&gt; &lt;/i&gt;-field amplitude and phase. Herein we report a novel approach to realizing sub-wavelength focusing based on the two-mode interference exited from an optical microfiber endface. By utilizing specific distributions of &lt;b&gt;&lt;i&gt;E&lt;/i&gt;&lt;/b&gt; -field amplitude and phase of two interacting optical modes, interference field patterns with a single focus (e.g., via a two-mode set of HE&lt;sub&gt;11&lt;/sub&gt; and HE&lt;sub&gt;12&lt;/sub&gt;) or multiple foci (e.g., via a two-mode set of HE&lt;sub&gt;11&lt;/sub&gt; and HE&lt;sub&gt;31&lt;/sub&gt;) can be obtained. Then, it is proved that the constructed foci will readily facilitate and selective trapping of nanoparticles. Circular polarization of optical mode is utilized in order to bring in angular symmetry of sub-wavelength focusing patterns compared with linear polarized optical modes. Our simulation results show that the smallest focal spot produced from the EH&lt;sub&gt;11&lt;/sub&gt; and HE&lt;sub&gt;12&lt;/sub&gt; mode interference has a full width at half-maximum (FWHM) of ~ 348 nm (i.e. 0.65&lt;i&gt;λ&lt;/i&gt;). Such a subwavelength focusing field is applied to the optical trapping of an 85 nm-diameter polystyrene nanosphere. Further calculation reveals that the stable trapping can be fulfilled with axial and transverse trap stiffness of 11.48 pN/(μm·W) and 64.98 pN/(μm·W), as well as axial and transverse potential well of 101 &lt;i&gt;k&lt;/i&gt;&lt;sub&gt;B&lt;/sub&gt;T/W and 641 &lt;i&gt;k&lt;/i&gt;&lt;sub&gt;B&lt;/sub&gt;T/W via two-mode interference of HE&lt;sub&gt;11&lt;/sub&gt; and HE&lt;sub&gt;12&lt;/sub&gt;. These values demonstrate the great improvement over conventional tapered fibers. Further investigations show that different foci, via a two-mode set of HE&lt;sub&gt;11&lt;/sub&gt; and HE&lt;sub&gt;31&lt;/sub&gt;, exhibit unlike trap stiffness and potential wells, justifying the potential for nanoparticle size sorting. Based on the flexible all-fiber device, this subwavelength focusing strategy by two-mode interference may find promising applications in optical manipulation, superresolution optical imaging, data storage and nanolithography.

Isolation of Extracellular Vesicles from Cell Culture and Blood Through Nano-Targeted DLD Microfluidic Device.

Extracellular vesicles (EVs) are secreted by cells and found in biological fluids such as blood, with concentration correlated with oncogenic signals, making them attractive biomarkers for liquid biopsy. The current gold-standard method for EVs isolation requires an ultracentrifugation (UC) step among others. The cost and complexity of this technique are forbiddingly high for many researchers, as well as for routine use in biological laboratories and hospitals. This chapter reports on a simple microfluidic method for EVs isolation, based on a microfluidic size sorting technique named Deterministic Lateral Displacement (DLD). With the design of micrometric DLD array, we demonstrated the potential of our DLD devices for the isolation of nano-biological objects such as EVs, with main population size distribution consistent with UC technique.

Dairy sheep and goats sort for particle size and protein in mixed rations

Sorting for specific parts or nutrients in feed is a natural behavior of ruminants, but for intensive dairy systems it is disadvantageous if it leads to nutritional imbalances for the individual or the herd. To prevent feed sorting in cattle, mixed rations (MR) are fed and forage components are cut as short as possible. In small ruminants, feed sorting is well documented but not well studied in relation to MR. The aim of this study was to investigate the ability of dairy sheep and goats to feed sort in MR. Experiments were conducted with each of 12 pairs of female adult dairy sheep and goats. In the first experiment, three MR composed of different forages (hay, grass silage, maize silage) were tested consecutively, each in a long and short cutting length variant. In the second experiment, two short cut variants of a grass silage-hay MR were investigated that differed in nutritional value. For all experiments, animals received each variant of MR for five consecutive days. The composition of feed rests at 11:00, 15:00 and the next day were compared to the ration fed at 09:00. Both species sorted all of the offered MR for large particles, and sheep but not goats sorted for protein. In the short cut MR variants, particle size sorting was reduced in the first two hours after feed delivery (09:00–11:00), but cutting length had no relevant effect thereafter, or on protein sorting. The nutritional value of the MR had no detectable influence on feed sorting. Both species sorted for larger particles in both variants, and goats sorted against protein in the first two hours after feed delivery, whereas sheep sorted for protein thereafter. These results show that sheep and goats are able to change the composition of MR within two hours after feed delivery. A short cutting length delayed feed sorting to a limited extent. Maintaining the feed quality of a mixed ration throughout the day is important for the health and welfare of dairy sheep and goats but seems to be a major challenge for feeding management.

Passive Focusing of Single Cells Using Microwell Arrays for High-Accuracy Image-Activated Sorting.

Sorting single cells from a population was of critical importance in areas such as cell line development and cell therapy. Image-based sorting is becoming a promising technique for the nonlabeling isolation of cells due to the capability of providing the details of cell morphology. This study reported the focusing of cells using microwell arrays and the following automatic size sorting based on the real-time recognition of cells. The simulation first demonstrated the converged streamlines to the symmetrical plane contributed to the focusing effect. Then, the influence of connecting microchannel, flowing length, particle size, and the sample flow rate on the focusing effect was experimentally analyzed. Both microspheres and cells could be aligned in a straight line at the Reynolds number (Re) of 0.027-0.187 and 0.027-0.08, respectively. The connecting channel was proved to drastically improve the focusing performance. Afterward, a tapered microwell array was utilized to focus sphere/cell spreading in a wide channel to a straight line. Finally, a custom algorithm was employed to identify and sort the size of microspheres/K562 cells with a throughput of 1 event/s and an accuracy of 97.8/97.1%. The proposed technique aligned cells to a straight line at low Reynolds numbers and greatly facilitated the image-activated sorting without the need for a high-speed camera or flow control components with high frequency. Therefore, it is of enormous application potential in the field of nonlabeled separation of single cells.

A novel lapping method for ultraprecision cylindrical rollers based on precision evolution

The geometrical precision of cylindrical rollers is a crucial factor influencing the rotation accuracy of the cylindrical roller bearing and limits of the rotation speed, load bearing capacity and serving life of the bearings. A novel lapping method with a circulating system for batch machining of ultraprecision cylindrical rollers is presented based on the principle of precision evolution. The variations of roller diameter and roundness are improved due to the effect of selective material removal. That is, more material is removed at the convex position for a single roller, and also for the balls with larger diameters, because higher stress concentrated in these areas will lead to plastic deformation and failure. Self-rotation of the rollers was realized by the application of electromagnetic force. Batch lapping of cylindrical rollers was carried out on a newly developed lapping system for approximately 500 rollers. After lapping 90 cycles, the variation of roller diameter for the randomly selected ten rollers, roundness and surface roughness were 0.76 µm, 0.4 µm and 14.93 nm, respectively. Additionally, the variation of roller diameter of 100 randomly selected rollers was 0.97 µm. This geometrical accuracy is higher than that of the highest standard class G1. This method realized the machining of ultraprecision rollers without size sorting and provided a solution for machining rollers with higher diameter consistency than that of the normal industrial manufacturing method. Based on the principle of precision evolution, this work provides a novel machining approach for batch machining of high precision cylindrical rollers.

Ontogenetic mechanisms of size change: implications for the Lilliput effect and beyond

AbstractBody size has a long history of study in paleobiology and underlies many important phenomena in macroevolution. Body-size patterns in the fossil record are often examined by utilizing size data alone, which hinders our ability to describe the biological meaning behind size change on macroevolutionary timescales. Without data reflecting the biological and geologic factors that drive size change, we cannot assess its mechanistic underpinnings.Existing frameworks for studying ontogeny and phylogeny can remedy this problem, particularly the classic age–size–“shape” space originally developed for studies of heterochrony. When evaluated based on metrics for age, size, and phenotype in populations, proposed mechanisms for size change can be outlined theoretically and tested empirically in the record. Using this framework, we can compare ontogenetic trajectories within and between species and determine how changes in size emerge. Here, we outline ontogenetic mechanisms for evolutionary size change, such as heterochrony, as well as how geologic factors can drive apparent, non-biological size change (e.g., taphonomic size sorting).To demonstrate the utility of this framework in actual paleobiological problems, we apply it to the Lilliput effect, a compelling and widely documented pattern of size decrease during extinction events. However, little is known about the mechanisms underlying this pattern. We provide a brief history of the Lilliput effect and refine its definition in a framework that can be mechanistically tested. Processes that likely produce Lilliput effects include allometric and sequence repatterning (including heterochrony) and evolutionary size-selective sorting. We describe these mechanisms and highlight relevant examples of the Lilliput effect for which feasible empirical tests are possible.

A new method proposed for realizing human gait pattern recognition: Inspirations for the application of sports and clinical gait analysis

BackgroundFinding the best subset of gait features among biomechanical variables is considered very important because of its ability to identify relevant sports and clinical gait pattern differences to be explored under specific study conditions. This study proposes a new method of metaheuristic optimization-based selection of optimal gait features, and then investigates how much contribution the selected gait features can achieve in gait pattern recognition. MethodsFirstly, 800 group gait datasets performed feature extraction to initially eliminate redundant variables. Then, the metaheuristic optimization algorithm model was performed to select the optimal gait feature, and four classification algorithm models were used to recognize the selected gait feature. Meanwhile, the accuracy results were compared with two widely used feature selection methods and previous studies to verify the validity of the new method. Finally, the final selected features were used to reconstruct the data waveform to interpret the biomechanical meaning of the gait feature. ResultsThe new method finalized 10 optimal gait features (6 ankle-related and 4-related knee features) based on the extracted 36 gait features (85 % variable explanation) by feature extraction. The accuracy in gait pattern recognition among the optimal gait features selected by the new method (99.81 % ± 0.53 %) was significantly higher than that of the feature-based sorting of effect size (94.69 % ± 2.68 %), the sequential forward selection (95.59 % ± 2.38 %), and the results of previous study. The interval between reconstructed waveform-high and reconstructed waveform-low curves based on the selected feature was larger during the whole stance phase. SignificanceThe selected gait feature based on the proposed new method (metaheuristic optimization-based selection) has a great contribution to gait pattern recognition. Sports and clinical gait pattern recognition can benefit from population-based metaheuristic optimization techniques. The metaheuristic optimization algorithms are expected to provide a practical and elegant solution for sports and clinical biomechanical feature selection with better economy and accuracy.

Effectiveness of complementary sorting methods in reducing aflatoxin contamination in groundnuts

Abstract Aflatoxin contamination of staple foods remains a public health concern in many tropical and sub-tropical countries. In sub-Saharan Africa, groundnuts are a significant source of aflatoxin (AF) in vulnerable populations such as infants and young children. However, there are limited scalable and affordable technological interventions to reduce the risk of aflatoxin ingestion in low and middle-income contexts. This study compared the effectiveness of complementary sorting methods in reducing AF contamination, time taken, and percentage loss of groundnuts. The study also evaluated bulk density and kernel weight as proxies for AF. Groundnuts were sampled from 19 bags at a medium-scale enterprise in Tanzania (Halisi) that processes cereal-based blended flours for complementary feeding. The samples were subjected to six sorting methods: (1) size (S) sorting, which yielded large and small fractions (n = 38); (2) density (D) sorting, which yielded heavy and light fractions (n = 38), (3) visual (V) sorting, (4) the combination of size and visual (SV), (5) the combination of density and visual (DV), and (6) the combination of size, density, and visual (SDV) which yielded grades 1, 2, 3, and 4 (n = 76). Samples of unsorted groundnuts and grades from all six sorting regimes (n = 418) were analysed for total aflatoxin by enzyme-linked immunosorbent assay. Analysis of variance (ANOVA) at a 5% significance level was used to compare AF reduction efficiency. Aflatoxin levels were reduced by 99% for the highest grade (G1) by the SDV sorting method. The SDV sorting method was the most effective in reducing AF contamination by removing 14% outsort (Grade 4) from 1 kg groundnut within 22 min. Bulk density and 100 kernels weight were inversely associated with AF, indicating their value as AF proxies. Scaling up such low-cost sorting methods can significantly reduce AF along the value chain and improve food safety.

Comparing Polarimetric Signatures of Proximate Pretornadic and Nontornadic Supercells in Similar Environments

Abstract While prior research has shown that characteristics of the supercell environment can indicate the likelihood of tornadogenesis, it is common for tornadic and nontornadic supercells to coexist in seemingly similar environments. Thus, some small-scale factors must support tornadogenesis in some supercells and not in others. In this study we examined polarimetric radar signatures of proximate pretornadic and nontornadic supercells in seemingly similar environments to determine if these radar signatures can indicate which proximate supercells are pretornadic and which are nontornadic. We gathered a collection of proximity supercell groups and developed a method to quantify environmental similarity between storms. Using this method, we selected pretornadic–nontornadic supercell pairs in close proximity in space and time having the most similar environments. These pairs were run through an automated tracking algorithm that quantifies polarimetric signatures in each supercell. Supercells with larger differential reflectivity (ZDR) column areas were more likely to become tornadic within the next 30 min compared to neighboring supercells with smaller ZDR column areas. In about two-thirds of pairs, the pretornadic supercell had a larger ZDR column area than the nontornadic supercell prior to its maximum low-level rotation, which is consistent with much prior work. The ZDR arcs could not discriminate between pretornadic and nontornadic supercells, and hailfall area was larger in pretornadic supercells. The separation distance between the specific differential phase (KDP) foot and the ZDR arc was larger in pretornadic supercells, yet was a limited result due to the small sample size used for comparison. Significance Statement Atmospheric conditions often indicate whether certain thunderstorms will produce tornadoes. However, sometimes multiple thunderstorms exist in a similar environment, and some produce tornadoes while others do not. Weather radar can identify signatures within thunderstorms that may give some indication of vertical motion, size sorting, and precipitation distributions. When multiple thunderstorms exist in a similar environment, there may be differences in these radar signatures that may indicate which thunderstorms are most likely to become tornadic. The key finding from this study is that pretornadic storms have larger radar-inferred updraft areas than neighboring nontornadic storms.