Eggshell Structure Research Articles

On the Structure and Role of Avian Eggshells: A 31P, 1H, and 13C Solid-State NMR Study.

The eggshell is a composite and highly ordered structure formed by biomineralization. Besides other functions, it has a vital and intricate role in the protection of an embryo from various potentially harsh environmental conditions. Solid-state nuclear magnetic resonance (SSNMR) has been used for detailed structural investigations of the chicken, tinamou, and flamingo eggshell materials. 31P NMR spectra reveal that hydroxyapatite and β-tricalcium phosphate in the ratio 3:2 represent major constituents of phosphate species in the eggshells. All three eggshells exhibit similar spectra, except for the line widths, which implies different structural order of phosphate species in the chicken, tinamou, and flamingo eggshells. 1H NMR spectra for these materials are comparable, differentiating overlapped peaks in three spectral regions at around 7, 4-5, and 1-2 ppm. These spectral regions have been attributed to protons from NH or CaHCO3, water, and possibly isolated monomeric water molecules or hydroxyl groups in calcium-deficient hydroxyapatite. 1H-13C CP MAS NMR revealed the presence of organic matter in the form of lipids and proteins. Two overlapped resonances in the carbonyl region at around 173 and 169 ppm are assigned to the carbonyls of the peptide bonds and the bicarbonate unit in calcite, respectively. Fourier-transform infrared spectroscopy (FTIR) spectra confirmed the presence of structural units detected in the NMR spectra.

Further screening of SNP loci of eggshell translucency related genes and evaluation of genetic effects

Eggshell translucency is a widespread issue in the field of egg quality. Previous research has established that the heritability of eggshell translucency is relatively low or moderate. Scientists have also successfully identified SNP loci related to eggshell translucency on different chromosomes by using gene chips and single-variant GWAS. However, the specific impact of single or multiple genes on the trait of eggshell translucency remains unknown. In an effort to investigate this, we examined 170 SNPs associated with eggshell translucency obtained by our research group. We selected 966 half-sibling laying hens from 2 generations in 3 pure lines: Dwarf Layer-White, Rhode Island Red-White Strain, and Rhode Island Red. Eggs were collected from each hen over a period of 5 consecutive days, and eggshell translucency was measured using a grading method in which the hens were divided into 2 groups: an opaque group and a translucent group. We collected blood samples from the laying hens and extracted DNA. Time of flight mass spectrometry (TOF-MS) was used for genotyping to identify SNP loci that influence the trait of eggshell translucency. The results of our analysis revealed that using TOF-MS in 3 chicken strains, we were able to eliminate loci with low gene polymorphism, genetic effect contribution less than 1%, and deviation from Hardy-Weinberg equilibrium. Ultimately, 5 SNPs (Affx-50362599, rs15050262, rs312943734, rs316121113, and rs317389181) were identified on chromosomes 1, 5, and 19. Additionally, nine candidate genes (DCN, BTG1, ZFP92, POU2F1, NUCB2, FTL, GGNBP2, ACACA, and TADA2A) were found to be associated with these SNPs. No linkage disequilibrium relationship was observed between the 2 pairs of SNP loci on chromosomes 1 and 19. Based on previous studies on the formation mechanism of eggshell translucency, we hypothesize that NUCB2, FTL, and ACACA genes may be affecting the eggshell structure through different mechanisms, such as increase the water permeability or make thin of eggshell membrane, which promote moisture or part of other egg contents and ultimately lead to the formation of eggshell translucency. These findings validate and identify five SNP loci that regulate the translucency trait, and provide molecular markers for breeding non-translucent populations. Furthermore, this study serves as a reference for further investigation of the genetic regulatory mechanisms underlying eggshell translucency.

Eggshell-Like Carbon Microspheres with Curvature Scheme: Distorted Energy Band and Atomic Charge Waves-Driven High Performance for Zinc-Air Battery.

A metal-free nanocarbon with an eggshell structure is synthesized from chitosan (CS) and natural spherical graphite (NSG) as a cathode electrocatalyst for clean zinc-air batteries and fuel cells. It is developed using CS-derived carbons as an eggshell, covering NSG cores. The synthesis involves the in situ growth of CS on NSG, followed by ammonia-assisted pyrolysis for carbonization. The resulting catalyst displays a curved structure and completely coated NSG, showing superior oxygen reduction reaction (ORR) performance. In 1 M NaOH, the ORR half-wave potential reached 0.93 V, surpassing the commercial Pt/C catalyst by 50 mV. Furthermore, a zinc-air battery featuring the catalyst achieves a peak power density of 167 mW cm-2 with excellent stability, outperforming the Pt/C. The improved performance of the eggshell carbons can be attributed to the distorted energy band of the active sites in the form of N-C moieties. More importantly, the curved thin eggshells induce built-in electric fields that can promote electron redistribution to generate atomic charge waves around the N-C moieties on the carbon shells. As a result, the high positively charged and stable C+ sites adjacent to N atoms optimize the adsorption strength of oxygen molecules, thereby facilitating performance.

Synergistic structural and electronic influences of Pt bead catalysts on dehydrogenation activity for liquid organic hydrogen carriers

Alumina-supported Pt bead catalysts with uniform (PtU/θ-Al2O3) or egg-shell (PtE/θ-Al2O3) structure and their corresponding potassium-doped counterparts (K-PtU/θ-Al2O3, K-PtE/θ-Al2O3) were synthesized to elucidate the influence of structure-induced active metal distribution and promotor on the dehydrogenation of liquid organic hydrogen carriers (LOHCs). Characterizations of the catalysts confirmed that different synthetic methods led to distinct Pt distributions on the Al2O3 surface. PtE/θ-Al2O3 and K-PtE/θ-Al2O3 had an average size of 1 nm with narrow Pt distributions while PtU/θ-Al2O3 and K-PtU/θ-Al2O3 exhibited bimodal distributions in Pt particle size (<0.2 nm and <0.8 nm), which also influenced the oxidation states. Introducing the promotor (K) facilitated electron transfer into Pt, which resulted in a more metallic state. When applied to the dehydrogenation of two different LOHCs, including methylcyclohexane and perhydro-monobenzyltoluene, K-PtE/θ-Al2O3 exhibited superior catalytic activity and durability compared to other catalysts. The improved activity of K-PtE/θ-Al2O3 was primarily attributed to the combined electronic influences of the catalyst bulk structure and promotor.

Eggshell microstructure, shell quality indices, mineralogy, and UV–Vis absorbance of domestic eggs of Iran

The structure and quality of eggshells (ES) vary around a mean value depending on different items, and these variations are important in their many industrial and technological applications as will be mentioned (vide infra). Five commercial egg brands of different laying hens are examined and their quality indices, morphological microstructure, elemental composition, and light absorbance at 200–700 nm UV/Vis spectra were compared. The ES layers include a limiting membrane, inner and outer shell membranes, a mammillary layer, a palisade layer, a surface vertical crystal layer, and a bilayer cuticle. The elemental composition of each layer reflects the proteinous or calcified nature of the layers, and various elements, C, O, N, Ca, Fe, Mg, Mn, Pb, Sr, Sc, Hf, Co, and La, were found. The weight difference between egg brands was significant, as well as the difference in ES percentage between white and colored eggs. ES weight possessed a positive relationship with the thickness of the calcified layer. So, the ES is heavier and the egg is larger and heavier when the calcified layer is thicker. The calculated average ES index was 7.99% ± 0.16 SE. In all ES samples, the absorbance in UV wavelength spectra (300–350 nm) was slightly higher than in Vis spectra (400 - 700 nm) and their difference was significant. The difference in absorbance of various treatments was significant and mean absorbance was the highest in the after-furnace (ash) samples and was the lowest for acid-treated ones. It seems that turning the ES into ash can improve the absorbance capability, especially in white ESs.

Mechanical design principles of avian eggshells for survivability

Biological materials exhibit complex structure-property relationships which are designed by nature's evolution over millions of years. Unlocking the fundamental physical principles behind these relationships is crucial for creating bioinspired materials and structures with advanced functionalities. The eggshell is a remarkable example with a well-designed structure to balance the trade-off as it provides mechanical protection while still being easy for hatching. In this study, we investigate the underlying mechanical design principles of chicken eggshells under various loading conditions through a combination of experiments and simulations. The unique geometry and structure of the eggshell play a critical role in achieving an excellent balance between mechanical toughness and ease of hatching. The effects of eggshell membranes are elucidated to tune the mechanical properties of the eggshell to further enhance this balance. Moreover, a mechanics-based three-index model is proposed based on these design principles, suggesting the optimal eggshell thickness design to improve survivability across a broad range of avian species with varying egg sizes. The survivability-design relationships hold great potential for the development of improved structural materials for applications in sports safety equipment and the packaging industry. Statement of significanceThe fundamental physical principles underlying the complex structure-property relationships in biological materials are uncovered in this study, with a particular focus on chicken eggshells as a prime example. Through the investigation of their mechanical design, we reveal the critical role of eggshell geometry and structure in achieving a balance between toughness and ease of hatching. Specifically, the crack resting effect is observed, making the eggshell easier to break from the inside than from the outside. Additionally, we explore the influence of eggshell membranes on this balance, contributing to the enhancement of the eggshell's mechanical properties. For the first time, we propose a three-index model that uncovers the underlying principles governing the evolution of eggshell thickness. This model suggests optimal thickness designs for diverse avian species, with the goal of enhancing egg survivability. These findings can guide the development of improved structural materials with advanced functionalities, enabling greater safety and efficiency in a wide range of applications.

Ultrastructural diversity in the shell of Artemia resting eggs.

The shell of Artemia resting egg, which is a delicate multilayered envelope surrounding the inside diapause embryo, plays an important role in the survival strategy of Artemia. To date, the ultrastructure of resting eggshell has been studied for only handful populations, and knowledge about the diversity of shell structure is still limited. In this paper, resting eggs from 13 Artemia populations were studied by transmission electron microscopy. Results show that the basic configuration of resting eggshell is quite conservative, but variations are not uncommon in the fine ultrastructure of each main layer of the shell (e.g., the shape and distribution of the radially oriented pores in the cortical layer; the size, number and arrangement of chambers in the alveolar layer; and the development state of outer cuticular membrane [OCM]). The ultrastructural variation of eggshell seems not to be linked with species and reproductive mode of Artemia. Resting eggs from very high habitats (4300+ m above sea level [a.s.l.]) on Qinghai-Tibet Plateau and certain tropical salterns have a hypoplastic OCM, which may be related to the adaptation to habitat conditions such as low oxygen concentration. RESEARCH HIGHLIGHTS: Comparative study on resting eggs from 13 Artemia populations reveals high diversity in the fine structure of eggshell. Resting eggs from very high (4300+ m a.s.l.) habitats commonly have a hypoplastic OCM.

Impact of biotechnological transgenesis procedures on duck productivity

The use of poultry as a unique model of biological research was characterised by a high level of efficiency, however, methods for creating transgenic ducks, complicated by the structure of waterfowl eggshells, are of low efficiency. The purpose of the study was to determine the influence of various biotechnological procedures for creating transgenic ducks on their productive qualities and reproductive ability to identify the optimal method for creating transgenic poultry for further use in scientific, research, or economic purposes. Weighting, morphometric and statistical analysis of productive traits were used during the study. 40 ducks (4 experimental groups of animals and about 3,000 of their eggs) were studied. The lowest value of the egg productivity index was obtained in the group created by busulfan injection (79.5±11.8%), the highest – in the group created by sperm-mediated gene transfer (91.8±2.3%), the group of direct injection of transgenic construct – 89.0±2.0%, which indicates that this biotechnological method of introducing transgenic construct did not have a clear effect on this indicator. The weight of ducks in different experimental groups ranged from 1,323.50±65.36 g (using the sperm-mediated gene transfer) to 1,608.08±94.76 g (in the group created using busulfan). Ducks that received direct injections had an average weight of 1,480.42±35.01 g. In the control group, the average weight at sexual maturity was 139.5±9.67 g, in the busulfan group – 148.2±13.13 g, in the direct injection group – 143.16±7.25 g, and in the spermmediated gene transfer group – 140.67±13.13 g. It was found that the method of injection into the embryo of a recipient sterilised with busulfan and the introduction of donor blastodermal cells negatively affect the reproductive qualities of ducks. The practical significance of the study lies in the fact that as a result of the analysis of the productivity of ducks obtained by various methods of transgenesis, it was determined that the most effective of the evaluated methods is the transfection of DNA of the transgenic construct with sperm (Sperm-mediated gene transfer, SMGT)

Enabling High-Performance Pressure and Proximity Dual-Mode Sensing with EGaIn/Ag/ZnO Egg-Shell Ternary Composite Particles.

Eutectic gallium-indium alloy (EGaIn) is a biocompatible liquid metal, promising for wearable electronics. Through functionalization and formation of composites, EGaIn-based materials have shown potential in multifunctional sensing devices. Here, egg-shell EGaIn/Ag/ZnO ternary composite particles were prepared through an ultrasound-assisted displacement reaction combined with room-temperature hydrolysis. The composite was further constructed as a wearable sensor capable of both pressure and proximity detection. For pressure sensing, due to the decrease in the Young's modulus of the egg-shell structure and the presence of the electrical double layers between Ag and ZnO, which enriched surface charges, the sensor showed excellent sensitivity at low pressures (2.17 KPa-1, <0.4 KPa) and thus the ability to sense body movements. For proximity sensing, the composite sensor was able to detect approaching objects that were up to 20 cm away. By combining and fitting the sensing curves for both the touchless and touching modes, the extracted parameters were used to create fingerprints for different objects, demonstrating the great potential of our sensor in the differentiation and identification of unknown objects for future robotics and artificial intelligence.

Integrative microscopy to explore physical and nanomechanical properties of eggshells of diapausing embryos in Rotifera: a proof-of-concept study

ABSTRACTDiapausing embryos of invertebrates represent investments in future populations. Thus, they must be capable of withstanding a variety of environmental assaults. Consequently, their eggshells should be adapted to resist injuries from predators, sediments, or excessive shrinkage if desiccated. To date, there have been no direct nanomechanical measurements of the eggshells of most invertebrates that produce diapausing eggs. Here, we used three approaches to understand how the eggshells of two rotifers, a freshwater species (Brachionus calyciflorus) and a brackish-water species (B. plicatilis), tolerate harsh conditions: (1) atomic force microscopy to measure elasticity and hardness; (2) transmission electron microscopy to study ultrastructure; (3) scanning electron microscopy to examine surface features. We compared these values to measurements of brine shrimp (Artemia salina) cysts and mosquito (Aedes aegypti) overwintering eggs. Our results revealed that rotifer eggshells are structurally similar and have comparable nanomechanical values. While rotifer eggshells had lower Young’s moduli (ca 13–16 MPa) and hardness values (1.84–1.85 × 10−2 GPa) than eggshells of Artemia and Aedes, eggshells of all species were relatively elastic and not particularly resistant to deformation. Pliancy of shells that form egg banks (ie Artemia, Brachionus) may be an adaptation to resist cracking under the physical forces associated with burial in sediments. Although there are no obvious relationships among eggshell thickness, ultrastructure, ornamentation, or nanomechanical values in rotifer eggshells, we hypothesise that eggshell composition may play an important role in determining elasticity and hardness. Future studies should consider an integrative approach to understand the importance of eggshell structure, chemistry, and mechanics in protecting diapausing embryos.

First ultrastructural description of an apomictic opsiblastic egg in freshwater Gastrotricha.

Freshwater gastrotrichs have a biphasic lifecycle that reputedly involves the production of three types of eggs: apomictic and fast hatching (tachyblastic ova), apomictic and delayed hatching (opsiblastic ova), and plaque-bearing eggs (potentially derived from mixis). While some details of oogenesis and eggshell structure are known for tachyblastic ova, there are few details on other egg types. Here, we provide the first ultrastructural description of the oviposited opsiblastic eggs of the freshwater gastrotrich, Lepidodermella squamata. Scanning electron microscopy revealed the eggshell surface to be ornamented with long flattened pillar-like structures centered on polygonal plates that are pitted along their periphery. Transmission electron microscopy showed the pits to lead to a vast labyrinth of tubular spaces and larger cavities throughout the thick apical layer of the shell. The basal layer of the shell is amorphous and connected to a network of fine fibers that traverse an extra-oocyte space and forms a protective sheet around the uncleaved oocyte. The uncleaved oocyte has a dense layer of peripheral ooplasm surrounding a core of organelles including mitochondria, membrane-bound secretion granules, endoplasmic reticulum, and a single nucleus in a granular, ribosome-rich cytoplasm. Secretion granules are the most abundant organelles and presumably contain lipid-rich yolk that will be used as energy for delayed cleavage, thus functioning in temporal dispersal. These data are compared to the fine structure of invertebrate resting eggs across the phylogenetic spectrum to determine the novelty of opsiblastic egg structure in L. squamata.

The effects of using UV light instead of formaldehyde in disinfection of hatching eggs on shell microbial load, embryo development, hatchability, and chick characteristics

ABSTRACT In this study, it was aimed to determine the effects of using UV light instead of formaldehyde in disinfection of hatching eggs on the microbial load, shell and yolk compositions, embryo development, hatching results and chick characteristics. 552 hatching eggs were divided into formaldehyde fumigation and disinfection with UV groups. After disinfection, bacteriological growth was not observed in groups. While the difference between the groups in terms of hatching results was insignificant, it was determined that the incubation period in the UV group was shorter than that of formaldehyde group. On the hatching day, relative chick weight and weight of bursa Fabricus were found to be higher in the UV group . UV light can be used as an alternative to formaldehyde as disinfection of hatching eggs because it is easy to use and does not cause any negative effects on egg shell structure, embryo development, hatching results and chick characteristics.

The Structure and Microbial Contamination Routes of Eggshell

Tavuk (Gallus gallus domesticus) yumurtası dış ve iç olmak üzere iki ana yapıdan meydana gelmektedir. Yumurtanın dış yapısını oluşturan kütikül, kalsifiye kabuk ve kabuk zarları mikrobiyal kontaminasyona karşı fiziksel ve kimyasal doğal bir bariyer oluşturmaktadır. Bu katmanların kalitesi özellikle mikroorganizmaların kontaminasyonunu ve yumurta içine penetrasyonunu belirlemektedir. Beslenme, kümes yapısı, çevre koşulları ve bulaşıcı hastalıklar kabuğun kalitesini doğrudan etkilemekte ve kirli, kırık veya şekli bozuk yumurta kabuğu oluşumuna neden olmaktadırlar. Düşük kabuk kalitesi ise tüketici tercihini olumsuz etkilerken aynı zamanda mikrobiyal kontaminasyon riskini artırmakta, gıda güvenliğini ve halk sağlığını tehdit etmektedir. Yumurtanın mikrobiyal kontaminasyonu endojen ve eksojen olmak üzere iki yolla gerçekleşmektedir. Yumurtlamadan hemen sonra yumurta kabuğu özellikle eksojen yolla kontamine olmaktadır. Tek sağlık konsepti içerisinde çiftlikten çatala gıda güvenliğinin ve halk sağlığının korunabilmesi için dekontaminasyon ve sanitasyon metotları ile biyogüvenlik kurallarına ve yasal düzenlemelere uyularak mikrobiyal kontaminasyon riski azaltılabilmektedir.

Do ontogenetic changes during incubation interfere with the interpretation of incubation mode in dinosaur eggs?

ABSTRACT Dinosaurs are oviparous reptiles that belong to Archosauria and whose closest modern relatives are crocodiles and birds. This is why, to shed light on the study of dinosaur reproduction, we conducted a test with the species Caiman latirostris (Crocodylia), a living archosaur. This paper focuses on the study of the embryos’ effect on the eggshells of Caiman latirostris during incubation. A total of 30 eggs from four nests including both embryonated and non-embryonated eggs were artificially incubated under the same conditions (incubation medium and temperature) to observe changes in eggshell structure throughout embryonic development. We found significant differences between eggs, in the embryonated eggshells we observed that the continuous calcium layer, became thinner, while at the same time we recorded an increase in the porosity of the eggshells both in the polar and equatorial regions. These changes could explain the variability recorded in fossil deposits with broods, where shells of the same oospecies were found at different levels and with differences in porosity and thickness. The results of this study will contribute to the methodology behind the inference of nesting environment and nesting strategies (buried, semi-buried or exposed) for fossil eggs, which typically utilises calculations of water vapour conductance.

SINGLE-ATOM ALLOY Pd&lt;sub&gt;1&lt;/sub&gt;Ag&lt;sub&gt;6&lt;/sub&gt;/Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; EGG-SHELL CATALYST FOR SELECTIVE ACETYLENE HYDROGENATION

In this work, a single-atom alloy Pd1Ag6/Al2O3 catalyst for the selective hydrogenation of acetylene was obtained with an egg-shell distribution of the active phase over the catalyst granules. The formation of an egg-shell structure was confirmed by electron probe microanalysis. It was found that metals are predominantly localized at a depth of 130–160 µm from the surface of the granules. Transmission electron microscopy and X-ray photoelectron spectroscopy have revealed the formation of a substitutional PdAg solid solution with electron density transfer from Ag to Pd. The formation of Pd1 single sites was confirmed by FTIR spectro-scopy of adsorbed CO. In the selective hydrogenation of acetylene the synthesized single-atom alloy Pd1Ag6/Al2O3 with egg-shell distribution showed high selectivity, which radically exceeds the selectivity of the palladium counterpart.

Surface texture heterogeneity in maculated bird eggshells.

Many of the world's 10 000 bird species lay coloured or patterned eggs. The large diversity of eggshell patterning among birds, achieved through pigment, has been attributed to a few selective agents such as crypsis, thermoregulation, egg recognition, mate signalling, egg strength and protecting the embryo from UV. Pigmentation may influence the texture of eggshells, which in turn may be important for dealing with water and microbes. We measured surface roughness (Sa, nm), surface skewness (Ssk) and surface kurtosis (Sku), which describe different aspects of surface texture, across 204 bird species with maculated (patterned) eggs and 166 species with immaculate (non-patterned) eggs. Using phylogenetically controlled analyses, we tested whether maculated eggshells have different surface topography between the foreground colour and background colour, and between the background colour of maculated eggshells and the surface of immaculate eggshells. Secondly, we determined to what extent variation in eggshell pigmentation of the foreground and background colour is determined by phylogenetic relatedness, and whether certain life-history traits are important predictors of eggshell surface structure. We show that the surface of maculated eggs consists of a rougher foreground pigment compared to the background pigment across 71% of the 204 bird species (54 families) investigated. Species that lay immaculate eggs showed no difference in surface roughness, kurtosis or skewness compared to background pigment of maculated eggs. The difference in eggshell surface roughness between foreground and background pigmentation was greater among species that occupied dense habitats, such as forests with closed canopies, compared to those that nest in open and semi-open habitats (e.g. cities, deserts, grasslands, open shrubland and seashores). Among maculated eggs, foreground texture was correlated with habitat, parental care, diet, nest location, avian group and nest type, while background texture was correlated with clutch size, annual temperature, development mode and annual precipitation. Surface roughness among immaculate eggs was greatest for herbivores, and species that have larger clutch sizes. Together, this suggests that multiple life-history traits have influenced the evolution of eggshell surface textures in modern birds.

Improvement of Redox Kinetics of Dendrite-Free Lithium–Sulfur Battery by Bidirectional Catalysis of Cationic Dual-Active Sites

The practical application of lithium–sulfur batteries (LSBs) is hampered by the slow lithium polysulfide (LIPS) conversion kinetics and the uncontrollable anode-metal lithium dendrites. Herein, a three-dimensional cation dual-active-site eggshell structure compound (3DCS-FMO@C) was synthesized by soft template, ion exchange, and pyrolysis to modify the commercial separator. Experimental and theoretical analysis results showed that Mn2+ and Fe2+ sites in 3DCS-FMO@C can synergistically adsorb LIPSs, effectively regulate the bidirectional conversion dynamics of intermediate liquid-phase LIPSs and solid-phase lithium sulfide, and reduce the energy barrier of the reaction. The 3DCS-FMO@C-modified separator with high mechanical stability and no reduction in ion diffusion also had a lithiophilic central core that can homogenize the lithium-ion flow, thereby inhibiting the dendrite growth of lithium. Based on the above advantages, 3DCS-FMO@C-modified separator LSBs had better electrochemical performance, including an initial capacity of 1530 mAh g–1 at 0.1C and an ultralow decay rate of 0.029% for 1000 cycles at 0.5C. A high area capacity of 8.7 mAh cm–2 was achieved even with high sulfur loading and poor electrolyte. This work provided a basis for understanding the bidirectional catalysis for practical application in LSBs and simultaneously solved the problem of lithium dendrites.

Eggshell composition and surface properties of avian brood-parasitic species compared with non-parasitic species.

The eggs of avian obligate brood-parasitic species have multiple adaptations to deceive hosts and optimize development in host nests. While the structure and composition of the eggshell in all birds is essential for embryo growth and protection from external threats, parasitic eggs may face specific challenges such as high microbial loads, rapid laying and ejection by the host parents. We set out to assess whether eggshells of avian brood-parasitic species have either (i) specialized structural properties, to meet the demands of a brood-parasitic strategy or (ii) similar structural properties to eggs of their hosts, due to the similar nest environment. We measured the surface topography (roughness), wettability (how well surfaces repel water) and calcium content of eggshells of a phylogenetically and geographically diverse range of brood-parasitic species (representing four of the seven independent lineages of avian brood-parasitic species), their hosts and close relatives of the parasites. These components of the eggshell structure have been demonstrated previously to influence such factors as the risk of microbial infection and overall shell strength. Within a phylogenetically controlled framework, we found no overall significant differences in eggshell roughness, wettability and calcium content between (i) parasitic and non-parasitic species, or (ii) parasitic species and their hosts. Both the wettability and calcium content of the eggs from brood-parasitic species were not more similar to those of their hosts' eggs than expected by chance. By contrast, the mean surface roughness of the eggs of brood-parasitic species was more similar to that of their hosts' eggs than expected by chance, suggesting brood-parasitic species may have evolved to lay eggs that match the host nest environment for this trait. The lack of significant overall differences between parasitic and non-parasitic species, including hosts, in the traits we measured, suggests that phylogenetic signal, as well as general adaptations to the nest environment and for embryo development, outweigh any influence of a parasitic lifestyle on these eggshell properties.

Engineering an egg-shell structure for the Ag/SiO2 pellet catalyst for selective hydrogenation of dimethyl oxalate to methyl glycolate

An egg-shell-type Ag/SiO2 pellet catalyst with an optimized thickness of the Ag-shell exhibits both enhanced activity and selectivity for DMO hydrogenation to MG.

Nematode eggshells: A new anatomical and terminological framework, with a critical review of relevant literature and suggested guidelines for the interpretation and reporting of eggshell imagery.

A literature review for a recent ultrastructural study of a trichinelloid eggshell revealed consistently occurring errors in the literature on nematode eggshell anatomy. Examples included nematodes of medical, veterinary, and agricultural importance in several orders. Previous researchers had warned of some of these errors decades ago, but a comprehensive solution was not offered until 2012 when a clarifying new anatomical and developmental interpretation of nematode eggshells was proposed by members of the Caenorhabditis elegans Research Community. However, their findings were explained using arcane acronyms and technical jargon intended for an audience of experimental molecular geneticists, and so their papers have rarely been cited outside the C. elegans community. Herein we (1) provide a critical review of nematode eggshell literature in which we correct errors and relabel imagery in important historical reports; (2) describe common reporting errors and their causes using language familiar to researchers having a basic understanding of microscopy and nematode eggs; (3) recommend a new hexalaminar anatomical and terminological framework for nematode eggshells based on the 2012 C. elegans framework; and (4) recommend new unambiguous terms appropriate for the embryonated/larvated eggs regularly encountered by practicing nematodologists to replace ambiguous or ontogenetically restricted terms in the 2012 C. elegans framework. We also (5) propose a resolution to conflicting claims made by the C. elegans team versus classical literature regarding Layer #3, (6) extend the C. elegans hexalaminar framework to include the polar plugs of trichinelloids, and (7) report new findings regarding trichinelloid eggshell structure.