Small Shell Research Articles

New taxonomical, distributional, and ecological data on the Helicodontidae (Gastropoda, Eupulmonata) of Crete (Greece)

Until now, the family Helicodontidae has been represented in Crete by two genera, Lindholmiola Hesse, 1931 and Helicodonta A. Férussac, 1821, with one species each, H. wilhelminae Maassen, 1991 and L. barbata (A. Férussac, 1821). We studied for the first time the reproductive system of H. wilhelminae and reclassify this species as Lindholmiola wilhelminae comb. nov. We present further details on its distribution and ecology and discuss the observed differences between recent and old shells. Based on the rich alcohol and shell materials in the Natural History Museum of Crete, we observed an impressive inter- and intra-population variability within L. barbata. The shells vary in form and size; small shells are associated with ecological factors and large shells with the northern part of Lefka Ori, the high mountains in western Crete. The reproductive system variation exceeds the limits of L. barbata species and confuses the species-specific characters of the genus, indicating the need for a new revision.

Costs of induced defenses dissipate by maturity for diploid and triploid oysters

Oyster reef restoration efforts and on-bottom aquaculture are frequently plagued with high predation rates. Oysters are phenotypically plastic, and rearing juvenile oysters, Crassostrea virginica, with predator cues causes them to grow stronger shells that increases survivorship in the field. However, induced defenses (e.g., shell hardening in oysters) are often associated with cost-benefit trade-offs, and the extent the increased shell strength persists into adulthood and alters the growth of somatic and reproductive tissues remains unknown. We raised diploid oysters (used in reef restoration) and triploid oysters (used in aquaculture) with and without predator cues for one month before placing individuals on an oyster farm to grow to market size. Oyster shell characteristics, soft tissue mass, and reproductive investment were measured periodically over one year of culture and compared across treatments. Both diploid and triploid oysters had significantly stronger and smaller shells than controls at the end of their nursery period. However, while diploid shells became 15 % stronger and 17 % smaller than controls, triploid shells became 28 % stronger and 23 % smaller. Additionally, triploid oysters exposed to predator cues returned to the size of controls faster and maintained their shell strength differences longer than diploids. Differences in soft tissue mass between treatments mirrored the patterns exhibited in shell size and weight with greater initial physiological costs and faster recovery for triploid individuals. There was no significant difference in somatic or reproductive tissue mass between induced and control oysters of the same ploidy after seven months in the field. Triploid oysters were 15–110 % larger than diploids depending on the characteristic measured at maturity. Additionally, there was a significant interaction between treatment and ploidy because induced triploids had marginally greater growth than their control counterparts while induced diploids had marginally less growth than controls. These findings demonstrate that physiological costs of oysters reacting to predators in early life stages are minimal by the time individuals reach maturity. Early exposure to predator cues is a promising tool for improving oyster survivorship in restoration and aquaculture operations, especially in regions with high predation pressure.

Discovery of Perun (G329.9-0.5): A New, Young, Galactic SNR

Abstract We present the discovery of possibly the youngest Galactic supernova remnant (SNR) with associated pulsar-wind nebula (PWN), which we name Perun (G329.9-0.5). Perun was serendipitously discovered in the Australian Square Kilometre Array Pathfinder (ASKAP) Evolutionary Map of the Universe (EMU) survey at 943 MHz, and subsequent follow up observations were conducted with the Australia Telescope Compact Array (ATCA) observatory at 5500 and 9000 MHz. We combine these with additional radio observations from the MeerKAT, Molonglo Observatory Synthesis Telescope (MOST) and MurchisonWidefield Array (MWA) telescopes, infrared (IR) observations from the Spitzer Space Telescope, and X-ray observations from the Chandra X-ray observatory to perform a multi-frequency analysis. The radio morphology shows a small angular size shell (D=70 arcsec) with a luminous, central PWN. We measure a total spectral index of α = −0.49 ± 0.05, which should be typical for a young, composite SNR. Crucial evidence for Perun’s SNR classification comes from the detection of linear fractional polarisation at radio frequencies of ∼7–10 per cent with both radial and tangential orientations, similar to the young SNR G1.9+0.3. We use data from the Southern Galactic Plane Survey (SGPS) to perform an H i analysis and estimate a favoured distance range of 6–9 kpc, and thus a favoured age range of ∼70–500 years. We find no high-energy emission in Fermi-LAT data. We detect Perun’s outer shell in 24 μm indicating the possible presence of [O iv] and [Fe iii] emission, also typical for young SNRs. Overall, these observations and analysis confirm Perun as a young, Galactic SNR with a prominent PWN.

Late Ediacaran to Early Cambrian stratigraphic correlation and its geological implications in the northwestern Sichuan Basin: insights from phosphorus, isotopes, and small shelly fossils

The characteristics of elements, isotopes, and small shelly fossils were investigated for Late Ediacaran to Early Cambrian stratigraphy division and to discuss their geological implications in the northwestern Sichuan Basin. The results reveal that small shelly fossils can be detected in the high-phosphorous section, with the concentration of phosphorus mainly ranging from 2% to 8%, suggesting that this interval belongs to the Early Cambrian, which is also consistent with the carbon isotopic composition results. In addition, the Early Cambrian is denudated in the Sichuan Basin due to tectonic movement, and the characteristics of some isotopes and small shell fossils are different from those in other basins. It can be proposed that P content can support the recognition of lithological boundaries, and the high phosphorus content can be used as a reference to identify the top and bottom boundaries of the Maidiping Formation in the study area. According to the elemental compositions in the Ediacaran Dengying Formation, the variations in Si, Al, Fe, and K contents are similar in the platform area and rift area, suggesting that the third and fourth member of the Dengying Formation are also developed in the Deyang–Anyue Rift. The results suggest that both the Deng-4 member and Maidiping Formation feature contemporaneous deposition of different facies in the northwestern Sichuan Basin. The strata consist of shale intercalated with thin carbonate rock deposits in the Deyang–Anyue Rift, while carbonate rock deposits in the platform. The Deyang–Anyue Rift expanded gradually in the Late Ediacaran and eventually filled in the Early Cambrian. The data in this study illustrate that elemental compositions, isotopes, and small shelly fossils can be combined to correlate the Late Ediacaran to Early Cambrian strata and provide new evidence for Deyang–Anyue Rift evolution. The results offer some new insights for deep oil and gas exploration in the Sichuan Basin and for the tectonic–depositional–environmental–biological synergistic evolution in the Late Ediacaran to Early Cambrian transition.

Two new species of Landouria Godwin-Austen, 1918 (Gastropoda, Camaenidae) from Thailand, with a key to Thai species.

The present work contains descriptions of two new species of Landouria and a key to Thai species of this genus. Landouriabella sp. nov. is described from isolated limestone hills in Ratchaburi and Phetchaburi provinces, western Thailand. This new species is characterized by its small depressed-globose shell without a peripheral keel, the presence of a small, thin lamella on the columellar side of the inner aperture, a long, cylindrical distally bent flagellum, a short penis with a rounded verge, and a short, thick free oviduct and vagina. The second new species, Landouriamonodon sp. nov. is described from sandstone hills in Kalasin Province, northeastern Thailand. This species has a depressed-conic shell with a blunt peripheral keel, a thick prominent lamella on the columellar side of the inner aperture, a short, finger-shaped, distally bent flagellum, and a long penis with a small, short verge.

Houses Speak Volumes About Their Inhabitants

The small shells of juvenile snails are highly important for paleontological research.

Role of outer shell electron-nuclear distant of transition metal atoms (TMA) on band gap reduction and optical properties of TiO2 semiconductor

The reduction of the band gap of titanium dioxide (TiO2) via transition metal atoms (TMAs) is the focus of many research groups to increase its absorption to visible region of electromagnetic (EM) radiation. In this modeling it was shown that atoms having near outer electron shells affect strongly on the band gap of TiO2. The TiO2 has exceptional photoactivity, high stability, and cost-effectiveness. The results of the current study emphasized that adjustable TiO2 photocatalyst material can be produced through band gap reduction by Pt, Pd, and Ni dopants. The electronic configurations and optical properties of both undoped and (Ni, Pd and Pt)-doped TiO2 have been studied using first-principles calculations within the framework of Density Functional Theory (DFT) with the aid of the Vienna Ab initio Simulation Package (VASP). The role of electronegativity of TMAs on band gap drop was discussed for the first time. The band gap of clean TiO2 was found to be 3.2 eV using the band structure (BS) and Tauq model. The results indicate that Ni TMA with lowest electronegativity reduces the band gap of TiO2 to the lowest value (0.86 eV). The results of BS and density of state revealed the fact that small outer shell electron-nuclear distant TMA more affected the band gap of TiO2. The band gap determined from the imaginary part of the optical dielectric function closely aligns with those determined from the BS diagram. The increase in the refractive index (n) was observed with the increase of Ni, Pd, and Pt into the TiO2 structure, which indicates an increase in charge density within the TiO2 structure. The reflectance, absorbance, and transmittance results suggest that Pd and Pt-doped TiO2 are responsive to the visible region of electromagnetic radiation, whereas Ni-doped TiO2 exhibits responsiveness in the IR region. In its pure state; TiO2 was found almost transparent in the visible and IR regions of EM radiation.

The construction of iron-based catalysts encapsulated by graphite for CO2 hydrogenation to light olefins

Developing efficient catalytic materials and unveiling the active factors are significant for selective hydrogenation of CO2 to light olefins (C2–4=). Herein, Fe3O4-FeCx nanoparticles coated by graphite without other doped elements were synthesized successfully. The optimal catalyst exhibited CO2 conversion of 48.0%, C2–4= space–time yield of 29.0 mmol·g−1·h−1, and a stability of 100 h (3.0 MPa, 320 °C, and GHSV = 12000 mL·g−1·h−1). The core–shell structure derived from the strong interaction between the phenolic hydroxyl group of resin and iron ions, as well as the encapsulation of the copolymer P123. The characterization results revealed that the size of core–shell particles and thickness of graphite layers could be regulated by P123, which affected the conversion of CO2 and products distribution significantly. Moreover, the combined results of quasi in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTs) and Raman spectra suggested small particle size and thin graphite shell strengthen the adsorption and conversion of CO2, playing an important role in the formation of light olefins. This work proposes a simple and feasible synthesis strategy to construct Fe3O4-FeCx particles encapsulated by graphite shell, which provides insights into catalysts design and the reaction mechanism of CO2 conversion to light olefins.

Microbubble-enhanced transcranial MR-guided focused ultrasound brain hyperthermia: heating mechanism investigation using finite element method

Recently, our group developed a synergistic brain drug delivery method to achieve simultaneous transcranial hyperthermia and localized blood–brain barrier opening via MR-guided focused ultrasound (MRgFUS). In a rodent model, we demonstrated that the ultrasound power required for transcranial MRgFUS hyperthermia was significantly reduced by injecting microbubbles (MBs). However, the specific mechanisms underlying the power reduction caused by MBs remain unclear. The present study aims to elucidate the mechanisms of MB-enhanced transcranial MRgFUS hyperthermia through numerical studies using the finite element method. The microbubble acoustic emission (MAE) and the viscous dissipation (VD) were hypothesized to be the specific mechanisms. Acoustic wave propagation was used to model the FUS propagation in the brain tissue, and a bubble dynamics equation for describing the dynamics of MBs with small shell thickness was used to model the MB oscillation under FUS exposures. A modified bioheat transfer equation was used to model the temperature in the rodent brain with different heat sources. A theoretical model was used to estimate the bubble shell’s surface tension, elasticity, and viscosity losses. The simulation reveals that MAE and VD caused a 40.5% and 52.3% additional temperature rise, respectively. Compared with FUS only, MBs caused a 64.0% temperature increase, which is consistent with our previous animal experiments. Our investigation showed that MAE and VD are the main mechanisms of MB-enhanced transcranial MRgFUS hyperthermia.

Theory of density waves and organization of proteins in icosahedral virus capsids.

Understanding the physical principles underlying the structural organization of the proteinaceous viral shells is of major importance to advance antiviral strategies. Here, we develop a phenomenological thermodynamic theory, which considers structures of small and middle-size icosahedral viral shells as a result of condensation of a minimum number of protein density waves on a spherical surface. Each of these irreducible critical waves has icosahedral symmetry and can be expressed as a specific series of the spherical harmonics Ylm with the same wave number l. As we demonstrate, in small viral shells self-assembled from individual proteins, the maxima of one critical density wave determine the positions of proteins, while the spatial derivatives of the second one control the protein orientations on the shell surface. In contrast to the small shells, the middle-size ones are always formed from pentamers and hexamers (referred to as capsomers). Considering all such structures deposited in the Protein Data Bank, we unexpectedly found that the positions of capsomeres in these shells correspond to the maxima of interference patterns produced by no more than two critical waves with close wave numbers. This fact allows us to explain the observed limit size of the icosahedral shells assembled from pentamers and hexamers. We also construct nonequilibrium thermodynamic potentials describing the protein crystallization and discuss the reasons behind the specific handedness of the viral shells.

Two new species of enid land snail from Sichuan, China (Stylommatophora: Enidae)

Two new species of enid land snail, Dolichena wenchuanensis n. sp. and Holcauchen multicostatus n. sp., are described from the dry-hot environment of Wenchuan, Sichuan, China based on conchological morphology. Dolichena wenchuanensis n. sp. can be easily distinguished from congeneric species by its smaller shell with fewer whorls, and H. multicostatus n. sp. can be easily distinguished from congeneric species by a ribbed post-nuclear shell. The two new species were found in a biological hotspot of the family Enidae. This discovery further enhances our understanding of the species diversity of Enidae in the dry-hot environment of China.

Small molecule-based core and shell cross-linked nanoassemblies: from self-assembly and programmed disassembly to biological applications.

Supramolecular assemblies of stimuli-responsive amphiphilic molecules have been of utmost interest in targeted drug delivery applications, owing to their capability of sequestering drug molecules in one set of conditions and releasing them in another. To minimize undesired disassembly and stabilize noncovalently encapsulated drug molecules, the strategy of core or shell cross-linking has become a fascinating approach to constructing cross-linked polymeric or small molecule-based nanoassemblies. In this article, we discuss the design and synthetic strategies for cross-linked nanoassemblies from small molecule-based amphiphiles, with robust stability and enhanced drug encapsulation capability. We highlight their potential biomedical applications, particularly in drug or gene delivery, and cell imaging. This feature article offers a comprehensive overview of the recent developments in the application of small molecule-based covalently cross-linked nanocarriers for materials and biomedical applications, which may inspire the use of these materials as a potential drug delivery system for future chemotherapeutic applications.

Proximate Analysis of the Paste of Three Varieties of Peanuts (Arachis Hypogaea) Consumed in Côte D’ivoire

Peanuts (Arachis hypogaea) since colonization have been an obligatory crop in Ivory Coast. It is currently the culture of women par excellence in the North of Côte d'Ivoire and especially in Korhogo. Almost the entire production is consumed on site and mainly in the form of peanut paste. The objective of this study is to determine the nutritional composition of peanut pastes of three varieties produced in Côte d'Ivoire. To achieve this, three varieties of peanut were studied and named according to their morphological characteristics (large striated shell (Gcs), medium striated shell (Mcs) and small smooth shell (Pcl). These grains were transformed into paste then subjected to analyzes to know their physicochemical characteristics. The results of statistical analysis showed significant differences at P  0.05. The variety that contains the least water is (Pcl), it will better resist microbial proliferation. Gcs peanut paste was much richer in fat with a value of 45.088  0.19% and also contained myristic acid (2.976  0.008%) and linolenic acid (0.263  0.002%). As for the Pcl variety, the linoleic and oleic acid contents were dominant compared to the other varieties respectively with values of 1.139  0.006 and 0.412  0.002%. Furthermore, regarding proteins, the Pcl variety presented a high level of proteins (29.00  1.75%), however, arginine, methionine, cysteine and glutamic acid are absent.

Karakterisasi Precipitated Calcium Carbonate (PCC) dari Cangkang Rajungan dengan Metode Karbonasi sebagai Biomaterial

Precipitated Calcium Carbonat (PCC) merupakan produk pengolahan material alam yang mengandung kalsium karbonat melalui serangkaian reaksi kimia. Karbonasi menjadi salah satu proses yang paling banyak digunakan untuk membuat PCC. Penelitian ini bertujuan untuk dapat mengetahui karakterisasi dari PCC yang dapat diaplikasikan menjadi biomaterial dari cangkang rajungan berdasarkan jenis kristal yang dihasilkan. Bahan baku utama cangkang rajungan yang digunakan diambil dari Pulau Madura, kandungan kalsium karbonat dalam cangkang dapat menjadi PCC dengan adanya reaksi kimia. Cangkang rajungan yang sudah dihaluskan dan diayak ukuran 100 mesh dibakar di dalam furnace pada suhu 900˚C selama 1 jam, kemudian dilarutkan dalam HCL 2N. Pelaksanaan penelitian dengan melakukan proses karbonasi melalui mengontakkan gas CO2 dengan larutan HCl dengan temperatur pengontakan sesuai dengan variabel. Pengujian yang dilakukan adalah analisa kadar cangkang rajungan menggunakan XRF (X-ray Fluorescence), XRD (X-rayDifraksi) untuk mengetahui jenis kristal dan SEM (Scanning Elec-tron Microscopy) untuk melihat bentuk kristal.

Shell size distributions, land use, and water quality relationships of a freshwater apple snail Pomacea canaliculata (Lamarck, 1822) in Maninjau Lake, West Sumatra, Indonesia

Abstract. Takarina ND, Soeprobowati TR, Komala PS, Subehi L, Wojewódka-Przyby? M, Nurdin D. 2023. Shell size distributions, land use, and water quality relationships of a freshwater apple snail Pomacea canaliculata (Lamarck, 1822) in Maninjau Lake, West Sumatra, Indonesia. Biodiversitas 24: 5478-5484. The freshwater apple snail, Pomacea canaliculata (Lamarck, 1822), is a common mollusk in lake ecosystems, including Maninjau Lake, West Sumatra. Despite its presence in Maninjau Lake, the information about its shell size, land use, and water quality variable relationships is very limited. This paper aims to study how the land use surrounding the lake and water quality variables can affect the shell size distributions of P. canaliculata. The samples were collected from several locations representing the varieties of land uses, including settlements, paddy fields, forest covers, and river mouths, along with water quality variables. Statistical analysis was done using ANOVA and validated by Tukey's post hoc test to analyze differences among locations. Pearson’s correlation test was used to analyze the relationship between shell size and water quality variables. The results show that the differences in land use and water quality variables affected the variations of shell length (P < 0.05, F = 4.925) and width (P< 0.05, F = 12.369) of P. canaliculata. The average shell length was 2.709 cm and 2.022 cm for the width. The large shell size was observed in settlement land uses (P< 0.05), and the small shell was observed in forest and paddy field land uses (P< 0.05). The water near settlement land uses was characterized by high temperatures, while colder water was observed in forest and paddy field land uses. Pearson’s test confirms that increases in shell length and width were correlated with increases in temperature and dissolved oxygen.

Should all Small Shell Posterior Malleolar Fractures be Considered for Fixation? Results from a 3D Fracture Mapping Study

Category: Ankle; Trauma Introduction/Purpose: Approximately 10-15% of posterior malleolar fractures (PMFs) are "small shell," extra-articular fragments. Current classification systems present difficulties to perform a uniform typification of PMFs and contain no consensus on whether they should be fixed. Anatomical studies have identified two distinct components of the posterior inferior tibiofibular ligament (PITFL); the superficial band is thought to be more important than its deep counterpart in imparting syndesmotic stability. However, the involvement of one or both bands of the PITFL by small shell PMFs has not been evaluated so far. Hence, we conducted this study to perform 3D mapping of small shell PMFs and to determine whether surgeons should fix these routinely. Methods: Ankle fracture patients with a ‘small shell’ PMF (Haraguchi 3/Mason 1/Bartoníček 1 or 2) were included. Demographics, radiological features, treatment, and outcomes were recorded. 3D models of the fractured tibiae were generated from CT scans and superimposed on a statistical shape model of the right tibia, which served as a template. Fracture lines along with footprints of superficial and deep PITFL were marked on the template. 3D fracture heat maps were generated. Size of the fracture fragments and involvement of the superficial and deep PITFL footprints were quantified using a custom MATLAB script (Figure 1). Sparing of the footprint was defined as an overlap of < 1% between the fracture line and the footprint areas. Odds ratios (OR) with 95% confidence intervals (CI) were determined to determine which variables correlated with sparing of the PITFL footprint; P-values of < 0.05 were considered significant. Results: Thirty-nine patients were included. The superficial PITFL footprint was spared in 15 (38%), deep PITFL in 10 (26%), and both in 4 cases (10%). Males and Weber C fractures had a higher likelihood of sparing the superficial and deep PITFL footprints, respectively (P = 0.04). Supination external rotation (SER) patterns were less likely to demonstrate syndesmotic widening if either PITFL footprint was spared. Direct fixation of the PMF was done in 1 case; syndesmotic fixation in 25 cases and in 14 cases, no syndesmotic fixation was done. Of these, 11 were SER injuries where stability was achieved after fixation of medial and lateral malleoli. In 1 SER and pronation external rotation (PER) injury case, the syndesmosis was stable after fixation of a large Chaput fragment. Conclusion: This study demonstrated that 48% of small shell PMFs spare either the superficial or deep footprint of the PITFL; in 10% both PITFL footprints were spared. Hence, 58 % of small-shell PMFs may not benefit from direct fixation. Additionally, SER injuries with small shell PMFs that spare either PITFL footprint may not demonstrate radiographic instability and may not need direct or indirect fixation after addressing other components of the ankle fracture. However, given the fact that syndesmotic stability is not dictated by the PITFL alone, it remains prudent to stress the syndesmosis per-operatively to determine if syndesmotic fixation is needed.

The first healed injury in a hyolith operculum.

The Palaeozoic sediments of the Barrandian area are globally well-known as a classic example of rocks characterised by an abundant skeletal marine fauna, including well-preserved remains of hyoliths. Several tens specimens of malformed invertebrates such as trilobites, cephalopods and gastropods have been collected and documented from Cambrian to Devonian clastic sediments and carbonates in this area. However, no malformed hyolith specimen has yet been recorded. Hyoliths are Palaeozoic animals with small calcium carbonate shells composed of the conch (= oblong, conical and bilaterally symmetrical shell of diverse cross section and aperture at its wide end) and the operculum (= cap closing the conch aperture). Here we describe an operculum showing regeneration after non-lethal predatory attack in the Ordovician hyolith Elegantilites custos. This is the first record of regeneration in a hyolith operculum that has been repaired after a failed durophagous attack. Epibenthic/infaunal predatory echinoderms, such as ophiuroids, are considered as potential culprits.

The stratigraphy and formation of Middle Stone Age deposits in Cave 1B, Klasies River Main site, South Africa, with implications for the context, age, and cultural association of the KRM 41815/SAM-AP 6222 human mandible

Cave 1B, in the Klasies River Main site complex (KRM), is best known for the recovery of the KRM 41815/SAM-AP 6222 human mandible. After initial skepticism over the modernity of this specimen, it is accepted that the mix of archaic and modern traits it displays is characteristic of early Homo sapiens individuals. Different authors have associated this specimen with the Middle Stone Age (MSA) I and II/Mossel Bay cultural phases, but the published data do not allow an unambiguous attribution. KRM 41815's frequent use in studies of the evolution of the human mandible, and its well-developed chin, makes clarifying its age and context important objectives. The field and micromorphology observations presented here provide greater insight into the stratigraphy and formation of the sequence exposed in the PP38 excavation. There are three major divisions: the basal Light Brown Sand (LBS) Member (not excavated), the Rubble Sand (RS) Member (MSA I), and the Shell and Sand Dark Carbonized (SASDC) Submember (MSA II). Cultural stratigraphy based on lithic artifacts remains the only way to make secure (but broad) temporal correlations with the rest of the site complex. This investigation shows that a range of anthropogenic, geogenic, and biogenic processes contributed to the deposition and post-depositional alteration of the identified microfacies. Short depositional hiatuses are reasonably common, and a significant hiatus was identified between the RS and SASDC. The impact of post-depositional processes on the RS is significant, with anthropogenic deposits poorly preserved. In comparison, the SASDC is dominated by hearths contained within deposits rich in reworked anthropogenic materials known as carbonized partings. Small shell disposal features are also present. The distribution of these anthropogenic features suggests continuity in the management of space throughout the MSA II occupations, from before 110 ka. New stratigraphic correlations indicate that KRM 41815 is unambiguously associated with the MSA I. Therefore, it predates 110 ka, with a lower age limit potentially in Marine Isotope Stage 6.

Microplastics in coastal farmed oyster (Crassostrea angulata) shells: Abundance, characteristics, and diversity

One of the most concerning emerging pollutants is microplastics (MPs), which can infiltrate soft tissues of organisms by ingestion, adhesion, and fusing and may even become embedded in biominerals. However, very little evidence is available about MPs in biominerals found in the wild. This study detected the abundance and characteristics of MPs in the shells of farmed oysters (Crassostrea angulata) off the coast of Taiwan and discussed the distribution, accumulation, and diversity in the oyster shells. The results showed that MPs were ubiquitous in oyster shells, with an average abundance of 0.70 ± 0.40 MPs/g. MPs abundance was significantly (p < 0.01) higher in small oyster shells (shell length < 6.5 cm, weight 5–10 g) and inorganic (CaCO3) fraction (HCl digestion) than in large oyster shells (>6.5 cm, 10–25 g) and an organic fraction (H2O2 digestion), respectively. However, there was no significant difference in MPs abundance between the top and bottom shells (p > 0.05). MPs with a size <2 mm accounted for 78.5 %, fibrous MPs for 93.7 %, and rayon for 89.5 %. The MPs diversity integrated index (MPDII) in oyster shells was low (0.27), and the small and fibrous MPs seemed more easily embedded in biominerals. The findings confirm the presence of MPs in oyster shells in coastal environments. In addition, oyster shells may contain higher amounts of MPs than soft tissues 4–5 times, which needs to be confirmed. Further revealing the distribution and accumulation of MPs in water/terrestrial biominerals will help to understand the fate of MPs in the environment.

Exploring the 3D Conformation of Hard-Core Soft-Shell Particles Adsorbed at a Fluid Interface.

The encapsulation of a rigid core within a soft polymeric shell allows obtaining composite colloidal particles that retain functional properties, e.g., optical or mechanical. At the same time, it favors their adsorption at fluid interfaces with a tunable interaction potential to realize tailored two-dimensional (2D) materials. Although they have already been employed for 2D assembly, the conformation of single particles, which is essential to define the monolayer properties, has been largely inferred via indirect or ex situ techniques. Here, by means of in situ atomic force microscopy experiments, the authors uncover the interfacial morphology of hard-core soft-shell microgels, integrating the data with numerical simulations to elucidate the role of the core properties, of the shell thicknesses, and that of the grafting density. They identify that the hard core can influence the conformation of the polymer shells. In particular, for the case of small shell thickness, low grafting density, or poor core affinity for water, the core protrudes more into the organic phase, and the authors observe a decrease in-plane stretching of the network at the interface. By rationalizing their general wetting behavior, such composite particles can be designed to exhibit specific inter-particle interactions of importance both for the stabilization of interfaces and for the fabrication of 2D materials with tailored functional properties.