Search

China leads the world in freshwater pearl production, an industry in which the triangle sail mussel (Sinohyriopsis cumingii) plays a pivotal role. In this paper, we report a high-quality chromosome-level genome assembly of S. cumingii with a size of 2.90 Gb—the largest yet reported among bivalves—and 89.92% anchorage onto 19 linkage groups. The assembled genome has 37,696 protein-coding genes and 50.86% repeat elements. A comparative genomic analysis revealed expansions of 752 gene families, mostly associated with biomineralization, and 237 genes under strong positive selection. Notably, the fibrillin gene family exhibited gene family expansion and positive selection simultaneously, and it also exhibited multiple high expressions after mantle implantation by transcriptome analysis. Furthermore, RNA silencing and an in vitro calcium carbonate crystallization assay highlighted the pivotal role played by one fibrillin gene in calcium carbonate deposition and aragonite transformation. This study provides a valuable genomic resource and offers new insights into the mechanism of pearl biomineralization. [ABSTRACT FROM AUTHOR]

Introduction: Intrastromal lenticule implantation is a promising treatment option for corneal pathologies, from refractive error to ectasia. In this narrative review, we intend to feature up-to-date literature supporting the use of lenticular tissue, a compelling method that can be customized for a variety of applications, providing an additional source of donor tissue for treating corneal diseases. Methods: We searched databases PubMed, Mendeley, and Scopus last accessed 10 May 2023, for literature on stromal lenticules and narrowed based on relevance. Review articles, animal studies, ex vivo studies, and book chapters were excluded, while assessable and relevant articles published in English were included. Results: Storage methods from using fresh lenticules to dehydration have proven successful, with cryopreservation maintaining structure and cellular viability for up to 10 years. Successful use of lenticules for treatment of numerous pathologies including corneal ectasias, hyperopia, and presbyopia with additional insight into the treatment of corneal ulcers and perforations are highlighted in this narrative review. Conclusion: Lenticular implantation is an innovative and advantageous treatment for various ocular pathologies, offering increased bioavailability, flexibility, and customization for patients. They can treat previously untreatable diseases and serve as a replacement for synthetic implants, with promising outcomes worldwide. Lenticular implantation has the potential to become a leading approach in ophthalmologic surgery. Further studies should aim to provide evidentiary support for a standardization of lenticule banking. [ABSTRACT FROM AUTHOR]

Fluoride toxicity is a leading cause of environmental pollution and is particularly considered as a phytotoxic element for cereal crops. Accumulation of high amount of fluoride in the soil alters the metabolism of plants and reduces their growth. Therefore, an experiment was conducted to understand the effects of sodium fluoride (NaF) on the plant growth and the amelioration of its toxic effects by the application of citric acid on the two cultivars of maize, Pak Afgoi (salt tolerant) and Pearl (salt sensitive). NaF in a concentration of 100ppm and 200ppm was applied to one week old seedlings. Citric acid (100 mgL-1 and 150 mgL-1) was applied as a foliar spray after two weeks of application of NaF salinity stress. The data regarding shoot length, shoot, root fresh and dry weight, chlorophyll a, chlorophyll b, total chlorophyll, carotenoids, ions and ash contents were collected after fifteen days of citric acid application. Our results showed that citric acid 150 mgL-1had a positive effect on the growth of maize plants and had reduced the toxic effects of sodium fluoride. [ABSTRACT FROM AUTHOR]

Pearl is a Middle English dream-poem in London, British Library, MS Cotton Nero A.x, of about 1400. It is attributed to the same author as the scriptural poems Patience and Cleanness and the romance Sir Gawain and the Green Knight also found in this manuscript. The four texts provide abundant information on fourteenth-century social life, including religion, particularly for devotion to the Blessed Virgin. Analysis of Marian imagery in Pearl and its related poems thus tells us much on the attitudes to Christ's mother of a high-ranking provincial layman of about 1390, especially for her as 'Queen of Heaven' and 'Queen of Courtesy', the latter term denoting the values of court society. Such analysis also tends to confirm attribution on other grounds of the four poems to Sir John Stanley (d. 1414), a magnate and courtier who in the last thirty years of his life dominated the politics of the Lancashire- Cheshire region of north-west England. [ABSTRACT FROM AUTHOR]

Pearl powder is a famous traditional Chinese medicine that has a long history in treating palpitations, insomnia, convulsions, epilepsy, ulcers, and skin lightining. Recently, several studies have demonstrated the effects of pearl extracts on protection of ultraviolet A (UVA) induced irritation on human skin fibroblasts and inhibition of melanin genesis on B16F10 mouse melanoma cells. To further explore the effect we focused on the whitening efficacy of pearl hydrolyzed conchiolin protein (HCP) on human melanoma MNT-1 cells under the irritation of alpha-melanocyte-stimulating hormone (α-MSH) or endothelin 1 (ET-1) to evaluate the intracellular tyrosinase and melanin contents, as well as the expression levels of tyrosinase (TYR), tyrosinase related protein 1 (TRP-1), and dopachrome tautomerase (DCT) genes and related proteins. We found that HCP could decrease the intracellular melanin content by reducing the activity of intracellular tyrosinase and inhibiting the expression of TYR, TRP-1, DCT genes and proteins. At the same time, the effect of HCP on melanosome transfer effect was also investigated in the co-culture system of immortalized human keratinocyte HaCaT cells with MNT-1. The result indicated that HCP could promote the transfer of melanosomes in MNT-1 melanocytes to HaCaT cells, which might accelerate the skin whitening process by quickly transferring and metabolizing melanosomes during keratinocyte differentiation. Further study is needed to explore the mechanism of melanosome transfer with depigmentation. [ABSTRACT FROM AUTHOR]

In this study, we investigated the impact of water temperature on pearl formation and the molecular mechanisms underlying this biomineralization process in the mussel Hyriopsis cumingii. In the laboratory experiment, recipient mussels received saibo grafts from donor mussels and then were cultivated at five temperatures (16, 20, 24, 28, and 32 °C) for 1 month. We found that speed of pearl formation varied with water temperature: there was no visible pearl granules at 16 and 20 °C, tawny pearl granules were collected at 24 °C and lustrous pearl granules were collected at 28 and 32 °C. The expressions of several nacreous layer matrix protein genes (hic22, hic24, HcTyr Hc-upsalin and Hcperlucin) at 28 °C and 32 °C were peaked on day 28, and the expressions of other nacreous layer matrix protein genes (hic52 and hic74) on day 28 were significant higher than day 14. In the natural environment, pearl deposition rate also increased as water temperature rose, and the optimum range for pearl growth in H. cumingii was between 28.3 and 30.3 °C. Expression of the prismatic layer-related matrix protein genes hic31 and both prismatic and nacreous layer-related matrix protein gene silkmapin was significantly high in winter, and expressions of the nacreous layer-related matrix protein genes (hic24, hic74, HcTyr, Hc-upsalin and Hcperlucin) were always higher during higher temperature seasons compared with winter. These results indicate that high water temperature can speed up pearl formation and further regulate matrix protein secretion to accelerate pearl nacre deposition. [ABSTRACT FROM AUTHOR]

British Library MS Cotton Nero A.x contains the unique copies of four important alliterative Middle English poems including Sir Gawain and the Green Knight —the chief source of the book's fame and focus of scholarly attention over the last century. At one point, this composite codex also contained two Latin manuscripts, compiled with the Middle English poems by early modern antiquarian collector Sir Robert Cotton. More than three centuries after Cotton assembled the volume, however, the British Museum extracted the Latin material and bound it separately from Gawain and the other English poems. This essay discusses the unique form of codicological miscellaneity that characterizes composite manuscripts like Nero A.x. The story of its early modern assembly and modern disaggregation illustrates how material histories can determine how we access and interpret medieval texts today. [ABSTRACT FROM AUTHOR]

Structural Causal Modeling (SCM) is an approach to causal inference closely associated with Judea Pearl and given an accessible instroduction in [Pearl, J., & Mackenzie, D. (2018). The book of why: The new science of cause and effect. Basic Books]. It is highly popular outside of economics, but has seen relatively little application within it. This paper briefly introduces the main concepts of SCM through the lens of whether applied economists are likely to find marginal benefit in these methods beyond standard economic approaches to causal inference. The most promising areas are those where SCM's causal diagrams alone offer significant value: covariate selection, the development of placebo tests, causal discovery, and identification in complex models. [ABSTRACT FROM AUTHOR]

Presbyopia may represent the largest segment of refractive errors that is without an established and effective refractive surgery treatment. Corneal Inlays are materials (synthetic or allogenic) implanted in the stroma of patients' corneas to improve presbyopia. These inlays, introduced into the United States in 2015 via the small-aperture corneal inlay (KAMRATM, SightLife Surgical/CorneaGen, Seattle, Washington, United States), were met with an initial wave of enthusiasm. Subsequent models like the shape-changing corneal inlay (RAINDROPTM, Revision Optics, Lake Forest, California, United States) offered excellent results for patients, but longer-term research raised questions about patient safety. At the time of this article, no synthetic corneal inlays are available in the United States for the correction of presbyopia. Other options for presbyopia correction include allograft corneal inlays, trifocal synthetic corneal inlays, pharmacologic therapies, scleral incisions or additive techniques and PresbyLASIK. Presently, allograft inlays consist of corneal lenticules removed from patients undergoing Small Incision Lenticule Extraction (SMILE). We will review corneal inlays and other alternative procedures that may provide effective and predictable treatments for patients with presbyopia. [ABSTRACT FROM AUTHOR]

• The mechanical enhancement mechanism of "brick-mortar" microstructure in natural pearl is enriched by strengthening inter-layer packing between boron nitride nanosheets. • P-N synergistic flame retardation with the same phosphorus source. • Directional stacked "brick-mortar" structure makes the composite material robust, self-extinguishing, and highly thermally conductive. Fabricating thermoplastic polyurethanes (TPU) that exhibit self-extinguishing properties alongside strong mechanical characteristics and high thermal conductivity represents a challenging yet imperative endeavor within both scientific research and industrial applications. Enhancing the thermal conductivity of composites necessitates meticulous attention to surface treatment and the orientation of chemically inert hexagonal boron nitride nanosheets (BNNS). In this study, BNNS are treated by Strengthening inter-layer packing, which enriches the mechanical enhancement mechanism of the "brick-mortar" structure of natural pearl layers. The treatments use copper hydroxyethylidene diphosphonate and melamine hydroxyethylidene diphosphonate, which have a synergistic flame retardancy. Self-extinguishing TPU films with strong mechanical strength (57 MPa) and high thermal conductivity (9.12 W m−1 K−1) are produced when the functional particles are oriented to create multiple synergistic effects with the TPU simultaneously. Furthermore, when comparing CP0.02/MP@BNNS-TPU composite film to BNNS-TPU film, the limiting oxygen index of TPU composites increased to 30.2 %, and there was a significant decrease in both the peak and total heat releases (77.2 % and 80.6 %, respectively), meeting the UL-94 V-0 standard. This work offers a fresh method for creating self-extinguishing materials with high heat conductivity and robust mechanical characteristics. [ABSTRACT FROM AUTHOR]

A novel method, the Pareto Envelope Augmented with Reinforcement Learning (PEARL), has been developed to address the challenges posed by multi-objective problems, particularly in the field of engineering where the evaluation of candidate solutions can be time-consuming. PEARL distinguishes itself from traditional policy-based multi-objective Reinforcement Learning methods by learning a single policy, eliminating the need for multiple neural networks to independently solve simpler sub-problems. Several versions inspired from deep learning and evolutionary techniques have been crafted, catering to both unconstrained and constrained problem domains. Curriculum Learning (CL) is harnessed to effectively manage constraints in these versions. PEARL's performance is first evaluated on classical multi-objective benchmarks. Additionally, it is tested on two practical PWR core Loading Pattern (LP) optimization problems to showcase its real-world applicability. The first problem involves optimizing the Cycle length (L C) and the rod-integrated peaking factor (F Δ h) as the primary objectives, while the second problem incorporates the mean average enrichment as an additional objective. Furthermore, PEARL addresses three types of constraints related to boron concentration (C b), peak pin burnup (B u m a x ), and peak pin power (F q). The results are systematically compared against conventional approaches from stochastic optimization. Notably, PEARL, specifically the PEAL-NdS (▪) variant, efficiently uncovers a Pareto front without necessitating additional efforts from the algorithm designer, as opposed to a single optimization with scaled objectives. It also outperforms the classical approach across multiple performance metrics, including the Hyper-volume. Future works will encompass a sensitivity analysis of hyper-parameters with statistical analysis to optimize the application of PEARL and extend it to more intricate problems. [ABSTRACT FROM AUTHOR]

All systems must adapt in order to survive, this is as true for a business organisation as any other system. A business exists in a turbulent environment and in order to maintain its relationship with its environment its managers have to adapt it to the circumstances. The effect of the present pandemic is an example with some staff working from home, active blended learning in the education sector and social distancing have all created an urgency to accommodate the unprecedented consequence of the situation. To effect the necessary changes that these circumstances have generated means exercising some form of power to change operating procedures. Change creates uncertainty, the threat of the reallocation of resources, delegated power, redundancies and a change in group relationships. This produces a feeling of insecurity in those within the organisation often resulting in resistance to the proposals in an attempt to maintain the status quo. They are faced with adapting or resisting to these changes. Whilst systems models of organisational behavior provide ideas about organizing and managing an enterprise these are of limited value because of the unpredictability of change. The ubiquity of communication technologies and the rise of virtual methods of working add to the pressure for change creating a climate of anxiety. Organisational power can no longer be framed by the measures once taken for granted. To this end I adopt a soft systems perspective to explore the impact of change upon an organisation and how those within react as they attempt to cope with its impact. [ABSTRACT FROM AUTHOR]

The color of horticultural shade nets is known to influence crop growth and quality because of variations in the amount and quality of light. Four ornamental plant species (celosia, begonia, gerbera, and fountain grass) were grown under aluminet, pearl, and red shade nets plus black as the control at 50% shade intensity for 8 weeks. Black had the least transmittance (~10% to 30% of ambient) within the red spectrum (620-750 nm), whereas red had the greatest at ~70% to 80%. Aluminet and pearl resulted in a similar reduction in photosynthetic photon flux at ~50% to 55% and ~55% to 65% of ambient, respectively. Aluminet increased the shoot dry weight for begonia and celosia, whereas no differences among shade nets were seen for gerbera or fountain grass. The chlorophyll concentration was greatest under aluminet for each species except begonia. Shade net color did not affect flower number. [ABSTRACT FROM AUTHOR]

The attractiveness of natural and cultured pearls is related, in part, to their colour. Raman spectroscopy was applied to natural and cultured pearls and the shells from 23 species of pearl producing molluscs, thus covering the majority of the natural and cultured pearls and their host animals found in the market today, in order to better understand their colouration and eventually to be able to identify the host animal. Pigments with a polyenic chain were identified in samples from 18 species. The vast majority were found to be a mixture of partially methylated polyenes, similar to those observed in octocorals. Samples with a similar colour but from different animal species can be sometimes related to a significantly different mixtures of such pigments. Only natural pearls from Pinna nobilis were found to be coloured by carotenoids. Raman spectra of other pigments were also observed on samples from four species, possibly linked with pigments from the porphyrin group. [ABSTRACT FROM AUTHOR]

BACKGROUND: To retain more biological activity of organic matter and materials, it is necressary to grind and refine the pearl powder by physical method. The ball grinding method can retain the organic matter in the pearl powder and its activity to the greatest extent. The nanomaterials prepared by ball milling in different dispersion media exhibit different effects. OBJECTIVE: To compare nano-pearl powder milled with distilled water and anhydrous ethanol. METHODS: Nano-pearl powder was prepared by grinding with anhydrous ethanol and water as dispersion medium respectively.The prepared nano-pearl powder was compared by scanning electron microscope, transmission electron microscope, X-ray diffraction, Kjeldahl method and by determining amino acid content in foods. RESULTS AND CONCLUSION: (1) The nano-pearl powder prepared with anhydrous ethanol as dispersion medium was mainly round particles of different sizes (range, 30-50 nm), with the average grain size of 20 nm. The relative percentege of calcite calcium carbonate increased to 7%. The contents of protein and amino acid did not change obviously. (2) The nano-pearl powder prepared with distilled water as dispersion medium was mainly round particles of different sizes with the average grain size of 30 nm. There were irregular grain-like or block-like particles. The relative percentage of calcite calcium carbonate increased to 10%. The contents of protein and amino acid decreased. (3) These results showed that there was a significant difference in the particle size of the pearl powder ground with distilled water and anhydrous ethanol. The pearl powder prepared with anhydrous ethanol as the dispersion medium had a finer more uniform particle size. [ABSTRACT FROM AUTHOR]

Purpose: This paper aims to present ball bearings with a composite structure based on the bionics principle and shows the comparison between five types of different structures. Design/methodology/approach: By means of the finite element method, the stress and other parameters between different structures are compared and verified. Finally, the comprehensive parameters of different structures are evaluated by the analytic hierarchy process method. Findings: The evaluation of the comprehensive parameters of five types of structures is shown here. Originality/value: The value of this paper is calculated and compared to the parameters of five types of different structures, and the parameter score evaluation of each structure is given. Different structures can be selected according to different parameter requirements, which to provide a theoretical basis for the design of ball bearings. Peer review: The peer review history for this article is available at: https://publons.com/publon10.1108/ILT-10-2019-0413 [ABSTRACT FROM AUTHOR]

We present the accurate terahertz spectra of between imitation and cultured pearls using continuous-wave terahertz (CW-THz) spectroscopy. Using Fourier transform infrared (FT-IR) spectroscopy and optical coherence tomography (OCT) measurements, cultured pearls can be distinguished from imitation pearls by observing distinct absorption peaks and discriminative boundaries. The THz absorption spectra up to 0.3 THz obtained from CW-THz spectroscopy show several absorption peaks at specific frequencies with the cultured pearls but no peaks with the imitation pearls, which results from the existence of the nacre polymorph of cultured pearls. Hence, it is expected that the CW-THz system proposed herein will be applicable to fast, nondestructive spectrum analysis including pearl identification. [ABSTRACT FROM AUTHOR]

The main objective of the study is to highlight the role of pendants in the general context of the jewelry art of the Northern Renaissance and Mannerism, the reasons for the popularization of this type of jewelry and offer a version of their classification. The methodological basis of the study is the application of iconological method of art history analysis to characterize the array of jewelry in the general context of artistic culture of the Renaissance and Mannerism of the countries, located north of the Alps; the historical method -- to characterize the jewelry works in a certain chronological sequence, mainly -- created in the second half of 16th and beginning of 17th centuries; comparative method -- to compare the stylistic features of jewelry of different countries of Europe and track their transformation over time. The scientific novelty of the study is in the fact that pendants of Northern Renaissance and Mannerism as the most popular type of personal jewelry have never been considered as an object of serious scientific interest, they were characterized previously in general context of arts and crafts of this period. Therefore, this essay attempts to show pendants as an independent phenomenon, a segment of jewelry fashion of the 16th and early 17th centuries in the Ukrainian science of art. The article makes an excursion into the European jewelry of the 16th century, outlines the types of jewelry in demand during this period, shows their main stylistic features. The materials and techniques preferred by the experts of Northern Europe in the 16th and early 17th centuries, the main subjects and ornamental motifs which existed in the decoration of jewelry, the reasons for their popularization are highlighted. A variant of the classification of pendants of this epoch is proposed, in which the dominant motif of the décor is chosen as the main criterion. The characteristics of individual pendants created during the Renaissance and Mannerism in Spain, the Netherlands, England, Germany, France. Data is collected from the collections of the State Hermitage in St. Petersburg, the Art Institute of Chicago, Victoria and Albert Museum and British Museum in London. [ABSTRACT FROM AUTHOR]

Pre-grafting conditioning is a crucial procedure before transplant surgery during pearl production. To investigate the molecular response of the pearl oyster Pinctada fucata martensii to conditioning, we constructed two hemocyte transcriptomes from pearl oysters with and without conditioning. A total of 134,222,686 raw reads were generated and assembled using the reference genome of the pearl oyster. Transcriptome analysis revealed 3,074 differentially expressed genes (DEGs). Gene ontology and pathway enrichment analyses revealed that these DEGs were mainly associated with "microtubule-based process", "regulation of actin cytoskeleton", and "cell cycle". All related genes were over-expressed in pearl oysters after conditioning. Some nucleotide-binding oligomerization domain-like receptors (NLR), toll-like receptor, myd88, proinflammatory cytokine interleukin-17 (IL-17), and apoptosis-related genes were highly expressed in pearl oysters after conditioning, indicating that conditioning induced the immune response of pearl oysters. "Fatty acid biosynthesis" (FA biosynthesis) was included in the enriched terms, and all eight FA synthase genes in this pathway were highly induced after conditioning. Four tandemly duplicated arginine kinase genes (PmAK) were found in the genome of P. f. martensii , gene structure and sequence analysis indicated PmAK genes were more diverse compared with that from human and zebra fish. The four tandemly duplicated PmAKs were highly up-regulated after conditioning. These findings will help to elucidate the responding molecular events after conditioning and explain the high pearl oyster survival rate with conditioning after transplantation, thereby providing useful information in perfecting the conditioning method to improve pearl oyster survival rate after transplantation. • Immune response was induced after pre-grafting conditioning. • Fatty acid biosynthesis were involved in the response to conditioning. • Four tandemly duplicated AK were found in the genome of P. f. martensii. • AK was functional in the energy production after conditioning. [ABSTRACT FROM AUTHOR]

Extrusion processing characteristics of whole grain flours of three major millets (finger, foxtail and pearl) were studied. Impacts of the extrusion processing conditions, including moisture (15, 17.5 and 20%), screw speed (300, 350 and 400 rpm) and barrel temperature (110, 120 and 130 °C), on the physicochemical properties of the millet extrudates was evaluated. Quality parameters of extrudates including, expansion ratio (ER), water solubility index (WSI), water absorption index (WAI) were measured. Variations in the structural properties were confirmed by macrostructural observation using scanning electron microscopy (SEM). Foxtail extrudates showed the highest expansion ratio (4.41) followed by pearl millet (3.78) and finger millet extrudates (3.18). WAI values for the foxtail millet, pearl millet and the finger millet extrudates were 4.18 g/g, 2.69 g/g and 3.54 g/g. respectively. Overall, the foxtail millet gave the best response, with the highest ER value achieved at 130C, with least SME input. The results highlight the potential use of whole millets flours in the development of direct expanded extruded foods. [ABSTRACT FROM AUTHOR]

This essay proposes that a number of the concerns expressed in Dracula can be read through Bram Stoker's employment of the imagery of precious metals and jewels. Focusing on the materiality of place - the treasure-laced landscape of Transylvania and the cliffs of Whitby famous for their reserves of jet - and the association between these materials and vampirism, I argue that analysing the symbolism of precious materials leads to a fuller understanding of many of the novel's key anxieties. Not only does this analysis demonstrate Stoker's elaborate use of jewel imagery in developing the notion of the female vampire as a hard, penetrative woman, it identifies the imperial implications of the trade in precious materials. In doing so, it claims that Stoker employs a 'language of jewels' in Dracula, through which he critiques the imperialistic plundering of Eastern lands, and demonstrates how these monsters - intimately entwined with these materials - attempt a rejection of Western appropriation. [ABSTRACT FROM AUTHOR]

Highlights • New method to extract lines from a point set. • Improvement regards to PEARL and RANSAC algorithms. • Application to an autonomous agricultural robot. • Proposal of a navigation algorithm based on the line detection. Abstract The purpose of the work presented in this paper is to develop a general and robust approach for autonomous robot navigation inside a crop using LiDAR (Light Detection And Ranging) data. To be as robust as possible, the robot navigation must not need any prior information about the crop (such as the size and width of the rows). The developed approach is based on line extractions from 2D point clouds using a PEARL based method. In this paper, additional filters and refinements of the PEARL algorithm are presented in the context of crop detection. A penalization of outliers, a model elimination step, a new model search and a geometric constraint are proposed to improve the crop detection. The approach has been tested over a simulator and compared with classical PEARL and RANSAC based approaches. It appears that adding those modification improved the crop detection and thus the robot navigation. Those results are presented and discussed in this paper. It can be noticed that even if this paper presents simulated results (to ease the comparison with other algorithms), the approach also has been successfully tested using an actual Oz weeding robot, developed by the French company Naio Technologies. [ABSTRACT FROM AUTHOR]

Shah Ismail Hatâyî (1487-1542) is also prominent figures of Turkish poetry in terms of literate person, as well as he is the emperor of the Safavid state which is founded in Iran and is an important character of XVI. Century political history. Therefore, the main roots of the three will arise as long as the actual history is solved forward. The Shah & Sultan novel is a name of the changeover from sheikdom to shaykh; the rulership that trying to create with sword, poetry, and love that Shah Ismail Hatâyî is a poet who has one of the shortest and most rooted pseudonyms of Islamic geography which came into being. The novel mirror to a public in front of Mistake which reflects contradictions and conflicts of having two different identities; at the same implying the time the anger of mankind, desperation, orisons, and courage. In this context, the basic power, which provides the existence of person and societies, is their loves that they carried today from ancestries, the concerns of existence and the concepts that they found themselves, the world of symbols/sign. Thus, societies comprehend true history by means of these concepts and symbols. The present-state-future of this hero moved to the reader with the world of symbols who presented as a consciousness/warden of a huge history and wants to flow away to the future by springing to life in pearls. The Shah & Sultan novel was shaped in the triangle of Mistake-Love- Rulership and presented as the manifestation of the self which finds itself in the line of the "love" that the protagonist can not come together in physical time and location. The main purpose of the study is to make sense of the seeking, finding himself and his society of an emperor who leads through the wind and fire under the love rulership in the light of the concepts and symbols that provides the transfer of values and the values that constitute the memory of the novel. [ABSTRACT FROM AUTHOR]

Recent rise of social attention towards ethical jewelry has led scientists to a challenge of how to construct analytical systems that can deliver in line with social and supply chain expectations. Of the various kinds of methods, "Proton/Particle-Induced X-ray Emission" (PIXE) seems to be robust and promising in characterizing gemstones because of its capability of trace element analysis without destruction. The authors established a non-standard method to analyze cultured pearls and applied it to test specimens from different places. The results showed that PIXE could detect important elements for pearl study with good accuracy and sensitivity and that pearl chemistry can be useful to differentiate freshwater and marine pearl products. [ABSTRACT FROM AUTHOR]

[Display omitted] • Parvatrema sp. is reported in Mediterranean mussels associated with pearl formation on the Northwestern Adriatic coast. • Pearls and metacercariae are found in the mantle of mussels at variable prevalence and intensity in the area. • All mussel size classes are infected and display pearl formation. Gymnophallids of the genus Parvatrema are small trematodes infecting waterbirds in their adult stage. Several species of clams and mussels have been found to act as first and second intermediate hosts, in which the trematode larval stages induce the formation of pearls. In this study, a wild population of Mytilus galloprovincialis was sampled along the Northwestern coast of the Adriatic Sea to evaluate the origin and extent of visible pearls. Parasitological investigations, including morphological and molecular analyses, and histopathology were carried out on a representative sample of mussels (n = 158) from June to September 2021. The overall prevalence of infection reached 75.3 %, and the intensity of infection ranged from a few trematodes to thousands per mussel, mostly occurring in the mantle and surrounded by variable numbers of conchiolin layers. Morphological studies allowed classification of the metacercariae as belonging to the genus Parvatrema , and the pairwise comparison of the obtained sequences, encompassing the internal transcribed spacer (ITS) region, revealed a genetic similarity (96.8 %) to Parvatrema duboisi. However, the phylogenetic analysis demonstrated the independent clustering of the obtained ITS sequences compared to other available Parvatrema species. For the relevant commercial impact that pearl formation may have on farmed mussels, ecological and epidemiological aspects of this infection would deserve further investigation in the area. [ABSTRACT FROM AUTHOR]

Agricultural use of plant protection products can result in exposure of bystanders, residents, operators and workers. Within the European Union (EU) FP7 project BROWSE, a tool based on a set of models and scenarios has been developed, aiming to assess the risk of exposure of humans to these products. In the present version of the tool only a first conservative tier is available for outdoor vapour exposure assessment. In the vapour exposure evaluation, the target concentrations in air at 10 m distance from the edge of a treated field are calculated for specific scenarios for each EU regulatory zone. These scenarios have been selected to represent reasonable worst case volatilisation conditions. The exposure assessment is based on a series of weekly applications in a five year period to cover a wide range of meteorological conditions. The volatilisation from the crop is calculated using the PEARL model and this PEARL output provides the emission strength used as input for the short term version of the atmospheric transport model OPS. The combined PEARL-OPS model is tested against measurements from a field experiment. First results of this test show that the mean concentration level was predicted fairly well. However, sometimes the differences between observations and simulations were found to be substantial. Improvements are suggested for the vapour exposure scenarios as well as for further model development. In the current version of the BROWSE tool a simplified procedure is used to assess single and multiple applications. The actual period of application and the time of application during the day are fixed, and the growth stage of the crop cannot be taken into account. Moreover, competing processes such as penetration of the substance into the plant tissue are not considered. The effect of these factors on the target exposure concentrations is discussed. [ABSTRACT FROM AUTHOR]

Laminated structure reduces the common inverse relationship of strength and toughness in many biological materials. Here the mechanical behavior of pearl and nacre with spherical and flat laminations was investigated and compared with the geological aragonite counterpart. The biological ceramics demonstrate higher strength, better reliability, and improved damage resistance owing to their laminated arrangement. Kinking and delamination occur in pearl to resist damage in addition to the crack-tip shielding mechanisms as in nacre, such as crack deflection, bridging, and platelet pull-out. The fracture mechanisms were interpreted in terms of the stress state using finite element simulation. This study may help clarify the compressive mechanics of laminated sphere between platens and advance the understanding on the mechanical behavior of biological and bio-inspired laminated materials. [ABSTRACT FROM AUTHOR]

Aulacomya atra populations of the San Jose gulf, Northern Patagonia, Southwestern Atlantic Ocean, are infested by two polydorin species, Polydora rickettsi and Dipolydora cf. giardi . The infestation by these boring polychaetes causes the formation of pearls which is evidenced by the presence of capsules containing polydorin tissue debris and the elemental composition of organic material inside the pearls. Moreover, a positive relationship between the abundance of perforations of polydorin polychaetes and abundance of pearls was found by applying generalized lineal model analysis. These results constitute the first evidence of pearls formation due to infestation by polychaete. [ABSTRACT FROM AUTHOR]

Appropriate development of the pearl-sac in pearl oysters is an important factor influencing the quality of cultured pearls. In this study, a total of 110 black-lip pearl oysters ( Pinctada margaritifera) with a mean (± SE) antero-posterior measurement of 110.82 ± 0.41 mm and dorso-ventral measurement of 112.06 ± 0.45 mm were grafted to allow histological examination and chronological description of pearl-sac development in this species. Beginning 2 days after grafting, oysters were sacrificed regularly until the 48th day and the pearl-sacs of sampled oysters were sectioned and examined. Graft tissue proliferated and developed into a complete pearl-sac within 14 days of grafting when the epithelial cells responsible for nacre secretion were fully developed. However, first nacre secretion onto the nucleus was not observed until 32 days after grafting. The presence and accumulation of haemocytes in the pearl pouch initially and in the pearl-sac thereafter is one of the primary factors potentially affecting pearl quality. Clumps of haemocytes present between the pearl-sac and nucleus caused distension of the pearl-sac from an ideally spherical shape. Furthermore, the presence of byssus in close proximity to the developing pearl-sac was demonstrated in this study. This has the potential to impact pearl-sac formation and resulting pearl quality. The findings reported in this paper provide a more detailed understanding of pearl-sac development in P. margaritifera and a basis for future research towards developing improved pearl culture practices and pearl quality. [ABSTRACT FROM AUTHOR]

Shell acidic matrix proteins are widely considered to be essential for shell formation given their low affinity and high loading for calcium ion. In the present study, a novel matrix protein, hic12, was isolated from the mantle of Hyriopsis cumingii. High expression in tissue and positive signals with in situ hybridization were detected in the mantle center and mantle pallium, indicating that hic12 mainly participated in the biomineralization of the shell nacreous layer. The expression pattern of hic12 in the pearl sac during early pearl formation indicated that it was involved in pearl biomineralization. Moreover, the recombinant protein, rGST-Hic12, was successfully expressed and purified. The addition of rGST-Hic12 could accelerate the calcium carbonate deposition rate, change the morphology of crystals, and promote the conversion of calcite to vaterite. These results may provide new insights into the molecular mechanisms of aragonite mollusk shell formation. rGST-Hic12 could promote the conversion of calcite to vaterite. [Display omitted] • A novel acidic matrix protein hic12 is discovered in Hyriopsis cumingii. • Hic12 could promote the conversion of calcite to vaterite. • The recombinant protein rGST-Hic12 could accelerate the calcium carbonate deposition rate, change the morphology of crystals and promote the conversion of calcite to vaterite. [ABSTRACT FROM AUTHOR]

• Comprehensive reflooding model has been developed in ASTEC V2.1. • Model is validated against PEARL experiments data on degraded core reflooding. • Wide range of thermalhydraulic and geometrical parameters has been considered. • ASTEC V2.1 can predict experiments involving both 1D/2D quench front progression. • Capillarity may be playing an important role in tests with 2 mm particle diameters. The injection of water into the reactor vessel at a late stage of a severe accident (core reflooding) is one of the key Severe Accident Management measure to stop the progression of the accident in Light Water Reactors. Therefore, an appropriate modelling of the physical phenomena involved in this process is of paramount importance for the enhancement of safety of these nuclear power plants. This article presents the improvements performed in the ASTEC V2.1 integral severe accident code in order to obtain a comprehensive reflooding model, which is valid regardless the core damage state. The main development consists in replacing, in presence of debris, the single momentum conservation equation (plus the drift flux relation) by two momentum conservation equations (one for each phase) with specific porous friction terms. Moreover, the calculation of the quench front position and the heat transfers downstream of the quench front have been harmonized. The physical models are validated against experimental data from the PEARL facility where a large heated debris bed is quenched. A wide range of thermal–hydraulic (pressure, injection velocity) and geometrical parameters (bed particle diameter and bypass thickness) is investigated. Generally, ASTEC V2.1 provides a good agreement for tests involving either a one or two-dimensional quench front progression. However, conversion ratios of produced steam to injected water seem to be overestimated in two-dimensional tests with fine particle diameters, which raises questions about the modelling of capillarity in those situations. The validated version of the code is then used to gain further insights on degraded core reflooding: radial steam redistribution is mainly driven by the large pressure gradients generated within the bed, whereas water entrainment is driven by the interfacial drag between the redistributed steam and the liquid, both contributing to hinder the coolability of the debris bed. [ABSTRACT FROM AUTHOR]

Pinctada fucata martensii is an ideal animal for study of biomineralization. Although dozens of genes have been identified, the molecular mechanism of biomineralization remains still unclear. The purpose here was to discover the expression profiles of nine biomineralization genes in related tissues: mantle edge ( ME), mantle centre ( MC) and pearl sac ( PS), and to explore the relationships between expression level and nacre thickness. The expression levels of seven genes ( ACCBP, aspein, CaM, EFCBP, KRMP, nacrein and prismalin-14) showed no significant difference between ME and MC, but were significantly higher than those in PS. The expression level of N19 was the same in ME and PS, significantly higher than that in MC. However, msi60 in ME, MC and PS showed no significant differences in expression level. In addition, the correlations of expression levels between ME, MC and PS were highly significant, indicating that there are some similar function and mechanism among the three tissues. Also the nine genes had significant correlation of expression levels between one another. Furthermore, no other genes from oysters which produced pearls of different grades showed significant difference in the expression level, except CaM in MC, which had significantly higher expression level in the medium pearl grade than in the plain nucleus grade. Moreover, the expression level of msi60 in MC of host oyster was significantly correlated with produced pearl layer thickness, suggesting that msi60 might play an important role in pearl formation and host oyster may also participate in the development of pearl. [ABSTRACT FROM AUTHOR]

Ethnopharmacological relevance Pearl and nacre are valuable traditional medicines to treat palpitations, convulsions or epilepsy in China for thousands of years. However, the active ingredients are not clear till now. Aim of the study The main purpose of the current investigation was to assess the anticonvulsant and sedative–hypnotic activity of pearl powder and nacre powder, including their corresponding 6 protein extracts. Material and methods Determination of the amino acid composition of the obtained protein was carried out by ultra-performance liquid chromatography (UPLC) combined with 6-aminoquinolyl- N -hydroxysuccinimidyl carbamate (AQC) pre-column derivatisation. The influence of the tested drugs on locomotor activity and convulsions latency was recorded. The contents of 5-Hydroxytryptamine (5-HT) and γ -aminobutyric acid (GABA) in brain were detected by enzyme-linked immunesorbent assay (ELISA) kits. In addition, immunohistochemistry was carried out to evaluate the changes of 5-HT3 and GABA B . In parallel, the expressions of them were demonstrated by western blot. Results The obtained data suggested that pearl original powder (1.1 g/kg), pearl water-soluble protein (0.2 g/kg), pearl acid-soluble protein (0.275 g/kg), pearl conchiolin protein (1.1 g/kg), nacre original powder (1.1 g/kg), nacre water-soluble protein (0.2 g/kg), nacre acid-soluble protein (0.7 g/kg) and nacre conchiolin protein (1.1 g/kg) could down-regulate the expression of 5-HT3 and up-regulate the level of GABA B to varying degrees compared with the control group. Besides, drug administration also reduced the locomotor activity and increased convulsions latency with a certain mortality. Conclusions These findings correlated with the traditional use of pearl and nacre as sedation and tranquilization agents, thus making them interesting sources for further drug development and also providing critical important evidence for the selection of quality control markers. [ABSTRACT FROM AUTHOR]

The value of a pearl depends upon five major traits — pearl size, colour, lustre, shape, and surface. To determine host and donor oyster contributions to these traits, a large-scale mantle seeding experiment was conducted in which grafts from 56 donors were used to induce pearl production in 1099 hosts of the silver-lip pearl oyster, Pinctada maxima . Pearls were harvested two years after seeding and individually graded. The amount of nacre deposition, lustre, and two types of defects were associated with host traits, whereas all traits were significantly associated with the donor oyster. A number of correlations between pearl quality traits were also found. These results suggest that potential exists to increase pearl quality via the selective breeding of host and donor oysters, but reveals that careful attention must be paid to potential trade-offs in the design of such breeding programmes. [ABSTRACT FROM AUTHOR]

An aragonite phase was present in the prismatic layer of high-quality freshwater-cultured pearls, whereas a vaterite phase was present in low-quality pearls. The Ca K-edge XANES spectra of high-luster freshwater-cultured pearl samples indicate the aragonite phase at 4040 eV, with binding energy around 4045 eV, a shoulder on the trailing edge at 4054 eV, and hump peaks at 4061 and 4065 eV. The XANES spectra of lusterless or low-luster pearls show the broader absorption of combined aragonite and vaterite phases at 4050 eV, and a specific vaterite peak at 4058 eV. [ABSTRACT FROM AUTHOR]

Electrospun fiber has highly structural similarity with natural bone extracelluar matrix (ECM). Many researches about fabricating organic–inorganic composite materials have been carried out in order to mimic the natural composition of bone and enhance the biocompatibility of materials. In this work, pearl powder was added to the poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and the composite nanofiber scaffold was prepared by electrospinning. Mineralization ability of the composite scaffolds can be evaluated by analyzing hydroxyapatite (HA) formation on the surface of nanofiber scaffolds. The obtained composite nanofiber scaffolds showed an enhanced mineralization capacity due to incorporation of pearl powder. The HA formed amount of the composite scaffolds was raised as the increase of pearl powder in composite scaffolds. Therefore, the prepared PHBV/pearl composite nanofiber scaffolds would be a promising candidate as an osteoconductive composite material for bone repairing. [ABSTRACT FROM AUTHOR]

Background: Color polymorphism in the nacre of pteriomorphian bivalves is of great interest for the pearl culture industry. The nacreous layer of the Polynesian black-lipped pearl oyster Pinctada margaritifera exhibits a large array of color variation among individuals including reflections of blue, green, yellow and pink in all possible gradients. Although the heritability of nacre color variation patterns has been demonstrated by experimental crossing, little is known about the genes involved in these patterns. In this study, we identify a set of genes differentially expressed among extreme color phenotypes of P. margaritifera using a suppressive and subtractive hybridization (SSH) method comparing black phenotypes with full and half albino individuals. Results: Out of the 358 and 346 expressed sequence tags (ESTs) obtained by conducting two SSH libraries respectively, the expression patterns of 37 genes were tested with a real-time quantitative PCR (RT-qPCR) approach by pooling five individuals of each phenotype. The expression of 11 genes was subsequently estimated for each individual in order to detect inter-individual variation. Our results suggest that the color of the nacre is partially under the influence of genes involved in the biomineralization of the calcitic layer. A few genes involved in the formation of the aragonite tablets of the nacre layer and in the biosynthesis chain of melanin also showed differential expression patterns. Finally, high variability in gene expression levels were observed within the black phenotypes. Conclusions: Our results revealed that three main genetic processes were involved in color polymorphisms: the biomineralization of the nacreous and calcitic layers and the synthesis of pigments such as melanin, suggesting that color polymorphism takes place at different levels in the shell structure. The high variability of gene expression found within black phenotypes suggests that the present work should serve as a basis for future studies exploring more thoroughly the expression patterns of candidate genes within black phenotypes with different dominant iridescent colors. [ABSTRACT FROM AUTHOR]

A sensitivity study was performed to assess the impact that uncertainties in the spectroscopic parameters of atmospheric species have on the retrieval of gas concentrations using the 265–280 GHz region of the electromagnetic spectrum. Errors in the retrieval of O 3 , N 2 O, HNO 3 , and ClO from spectra measured by ground-based radiometers were investigated. The goal of the study was to identify the spectroscopic parameters of these target species, and other interfering species, available in the JPL and HITRAN 2008 catalogues, which contribute the largest error to retrieved atmospheric concentration profiles in order to provide recommendations for new laboratory measurements. The parameters investigated were the line position, line strength, broadening coefficients and their temperature dependence, and pressure shift. Uncertainties in the air broadening coefficients of gases tend to contribute the largest error to retrieved atmospheric concentration profiles. For O 3 and N 2 O, gases with relatively strong spectral signatures, the retrieval is sensitive to uncertainties in the parameters of the main spectral line that is observed. For HNO 3 , the uncertainties in many closely spaced HNO 3 lines can cause large errors in the retrieved profile, and for ClO, the error in the profile is dominated by uncertainties in nearby, stronger O 3 lines. Fourteen spectroscopic parameters are identified, for which updated measurements would have the most impact on the accuracy of ground-based remote sensing of the target species at 265–280 GHz. [ABSTRACT FROM AUTHOR]

Chest photodamage is a common cosmetic complaint. Laser treatment of the chest may be higher risk than other areas. The objective of this study was to assess the safety and efficacy of 2,790-nm chest resurfacing for photodamage. Twelve patients with Fitzpatrick skin types I-III were enrolled in this university IRB-approved study. Photo documentation was obtained at baseline and each visit. A test spot with the 2,790-nm resurfacing laser was performed on the chest. Patients who did not have adverse effects from the test spot went on to have a full chest resurfacing procedure. Patients were instructed on standardized aftercare, including sunscreen. A 5-point healing and photodamage improvement scale was used to rate improvement by both investigators and the patients and was obtained at 2 weeks, 1 month, 2 months, and 3 months. One pass chest treatment with the 2,790-nm resurfacing laser at fluences greater than or equal to 3.0 mJ with 10 % overlap leads to unacceptable rates of hyperpigmentation. Double pass chest treatment at fluences less than or equal to 2.5 mJ with 10 % overlap leads to mild improvement in chest photodamage parameters without significant or persistent adverse effects. Laser treatment of aging/photodamaged chest skin remains a challenge due to the delicacy of chest skin. Mild improvement may be obtained with double pass resurfacing with the 2,790-nm wavelength. [ABSTRACT FROM AUTHOR]

The relationship between optical behaviour and microstructure of pearl was studied by laser scanning confocal microscopy, high resolution scanning electron microscopy and atomic force microscopy. There are three optical effects in pearls, namely, the reflection-diffraction effect, a chromatic diffusion halo and the whispering gallery effect. From the structure observation for pearls, we proposed that the first optical effect exhibited by pearls is dominated by the surface diffuse reflection. In addition, the multilayer interference and diffraction have little contribution. With delicate observation for the structure of pearl by an atomic force microscope, it is revealed that the polygon platelets of pearl are not single crystals but nanograins of aragonite in the network of organic matrix, which is responsible for the chromatic diffusion halo. As for the third optical effect, it originates from the stratification structure, which is composed of aragonite platelets. When the light falls on the surface of the pearl, it will travel along the laminations of its structure rather than through the whole pearl, so the rim of the pearl is bright even if no light falls on the surface directly. [ABSTRACT FROM AUTHOR]

The paper concerns some crucial issues of theology and cosmogony of the Yezidis, which have distinct parallels in the writings of the ancient Greeks. A startling coincidence of certain topics and the manner of approach can lead to the conclusion that the Yezidi theology and mythology seem to have a distant genetic relationship with the Greek theology, or--which is also possible--we are dealing with distinct independent inscriptions of the same ideas, meaning here the highest factors governing the world. The paper also contains references to similar topics in the literature of Early Christianity and Gnosticism. [ABSTRACT FROM AUTHOR]

Abstract: The initial formation stage and succedent biomineralization of pearls were studied using scanning electron microscopy, Raman spectroscopy, transmission electron microscopy and atomic force microscopy. A new initial formation phase with needle-like structure which is found to be nanocrystallites of aragonite was discovered. As a result, two possible formation modes are proposed to describe the initial formation stage of pearls. As for the succedent mineralization of “brick and mortar” structure, nanostripes were first discovered inside the “brick” (aragonite platelet), compared with the foregoing finding of nanograins. The various nanostructures of aragonite platelet allow us to reconsider the role of the inter- and intracrystalline organic material surrounding CaCO3, and a possible biomineralization mechanism was proposed. [Copyright &y& Elsevier]

Quality evaluation of pearls has been traditionally performed by well-trained experts with the naked eye. Among several characteristics, interference color is a key factor for determining pearl quality. The interference color largely stems from the structure of the pearl's nacre. In the present study, a method for the optical measurement of the interference color and the determination of its relation to the subjective quality of pearl from the spectral characteristics of light transmitted through the pearl is proposed. The spectral characteristics of the interference colors showed a clear dependence on the subjective quality. To quantify and visualize pearl quality, the wavelength of the interference color that shows a high correlation with subjective quality was selected. A validation test with another set of pearls confirmed that the results of the proposed method were highly correlated with those of expert visual evaluation. [ABSTRACT FROM AUTHOR]

In this essay I provide a brief exegesis of the parable of the 'pearl of great price' (Matthew 13:45-46) as an introduction to an examination of Elphaba's character in the Broadway musical Wicked [as distinguished from her character in Gregory Maguire's novel, Wicked ()] and the potential value this character has for pastoral care with adolescent girls who struggle with the need to belong as well as the need to be themselves. I argue that Wicked may be understood as a twenty-first century parable that appeals to many, adults and adolescents alike, but it is especially appealing to teenage girls because it 'taps into a certain teenage angst' () that relates to the quest for popularity, a first true love, and beauty makeovers. Elphaba's seriousness has a certain kind of spiritual nature which may be related to her green skin (James , p. 160) that may encourage adolescent girls to adopt their own spiritual natures and enable them to claim their own voices even as Elphaba finally 'defies gravity' and learns to fly. [ABSTRACT FROM AUTHOR]

Abstract: The silver-lip pearl oyster, Pinctada maxima, produces the largest and most valuable pearls in the world. Despite the importance of this species very little is known about genetic parameters of commercially important pearl traits. As an initial step towards developing a selective breeding program, site selection effects, donor oyster derived genetic parameters and genotype by environment (G×E)interactions were estimated for pearl quality traits of P. maxima, originating from three populations (Aru, Bali, West Papua), reared at two commercial grow-out locations in Indonesia (Bali and Lombok). Microsatellite-based DNA parentage analyses were used to assign oysters to families and population of origin. Six pearl traits that are together the major determinants of pearl value (pearl weight (g), size (mm), shape, colour, complexion and lustre) were recorded at harvest. Pearls produced at the Lombok site were bigger and more valuable compared to pearls produced at the Bali site (P <0.05). G×E interactions were present for size (rg =−0.22), colour (rg =0.28), weight (rg =0.38), shape (rg =0.56) and lustre (rg =0.59) due to re-ranking of relative family performances at the two sites, although there were large standard errors associated with these estimates. Complexion was the only trait that showed little evidence for re-ranking (rg =0.85). Donor related-heritability estimates for size (h2 =0.13), lustre (h2 =0.14), weight (h2 =0.15), colour (h2 =0.15) and shape (h2 =0.06) were low, while for complexion estimates were moderate (h2 =0.25). A positive and high genetic correlation was found between pearl size and weight (rg =0.99), shape and complexion (rg =0.65) and shape and colour (rg =0.62); however, interestingly pearl weight was negatively genetically correlated with shape (rg =−0.46), complexion (rg =−0.11), colour (rg =−0.03) and lustre (rg =−0.15). Given the complex relationship amongst pearl quality traits and the likelihood for G×E interaction effects care should be executed when designing breeding objectives for the genetic improvement of these traits in P. maxima. [Copyright &y& Elsevier]

Abstract: Marine mollusc shell growth has been widely measured using fluorochrome marking. In order to test the efficiency and reliability of calcein staining on Pinctada margaritifera shells and pearls, the present study examined two administration methods, different concentrations and several immersion times. Immersion in a 150mgL−1 calcein solution for 12h to 24h appeared to be the best method for marking P. margaritifera shells. For pearl marking, injection of a 200mgL−1 calcein solution into the pearl pouch was the optimal method. Calcein marking was then used to measure the influence of food resource levels on the shell growth. Groups of 23-month-old P. margaritifera were fed at three trophic levels for two months. The two highest food levels tested (6000cellmL−1 and 15000cellmL−1) induced uniform growth between the dorsal and ventral sides of shell, whereas the lowest food level (800cellmL−1) induced greater growth on the dorsal side. Shell deposits from the ventral side were observed using a scanning electron microscope, revealing that the difference of the trophic level over two months had modified the thickness of the aragonite tablets formed. These results showed that the trophic level is a major factor conditioning P. margaritifera development. [Copyright &y& Elsevier]

Introduction: To mimic the impressive mechanical behavior of natural ceramics for technical or biomedical applications, interest has been focused on nacre, a natural composite consisting of imbricated aragonite platelets embedded in a protein matrix. Nacre is an ideal model material for implants, since it possesses favorable strength and toughness properties compared to the component materials of which it is composed. The focus of the present study was to test standardized parameters which are good indicators of the material's suitability as an implant material. Materials and methods: A three-point bending test was performed on polished nacre samples according to international standards for Young's modulus, bending strength and fracture toughness. A total of 60 nacre samples were tested, with 5 samples each in 4 states of hydration (dry, distilled water, 0.9% NaCl and sea water). As a basis for comparison, 10 samples of a newly developed bioceramic material were tested for fracture toughness. Results: The fracture toughness of nacre tended to be higher for specimens conditioned in 0.9% NaCl than for dry specimens (5.3 ± 0.6 vs. 4.3 ± 0.7 MPam, p = 0.061). The fracture toughness of the bioceramic investigated was observed to be somewhat higher than nacre (5.8 ± 0.4 vs. 4.3 ± 0.7 MPam, p ≤ 0.001). Discussion and conclusion: The increase in fracture toughness of hydrated nacre was not as large as would be expected based on the difference in stiffness of the matrix material after hydration that has been reported. Modulus and toughness were similar to published values and the fracture toughness observed was somewhat higher than reported for alumina implant ceramics, which are in use in total hip arthroplasty. In a direct comparison, we found that a newly developed alumina bioceramic material can in fact match nature in terms of fracture toughness. [ABSTRACT FROM AUTHOR]

According to the EU directive 91/414/EEC potential environmental concentrations of pesticides have to be assessed with environmental fate models. For the calculation of pesticide concentrations it is necessary to provide an application date which has to match the specific Biologische Bundesanstalt, Bundesamt, Chemische Industrie (BBCH) stage at which the pesticide shall be applied. If these application dates are not available for a specific stage, crop and country they must be estimated, which adds an additional uncertainty to the predicted concentrations. In the present study, we therefore evaluate to which extent application dates can be derived from phenological data. For this analysis phenological data, converted to BBCH stages, of two field crops provided by the German Weather Service (DWD) were analyzed. We found a linear correlation between BBCH stages and the respective appearance dates, which can be used for interpolation of appearance dates of specific BBCH stages. Remarkably, when comparing BBCH stages from Germany and the Czech Republic almost identical correlations of appearance dates and BBCH stages were found. In the next step, soil and climate data from Joint Research Centre (JRC) were analyzed together with phenological data in order to evaluate if BBCH stages can be estimated for countries with other climate or soil conditions. This analysis revealed that temperature, global radiation and evaporation were the parameters with the strongest impact. These parameters were used for estimating appearance dates of BBCH stages for other countries. Exemplarily, appearance dates for maize BBCH were calculated for Italy. Estimated and observed appearance dates showed a high concordance (on average six days difference). Finally, the political of impact a variation of a few days on calculated pesticide concentration was analyzed. Exemplarily, the pesticide fate model FOCUS PEARL was used to estimate pesticide groundwater concentrations. When calculating concentrations for application dates varying by ± two weeks, concentrations in groundwater usually varied very little. The highest variation was found for application at BBCH 30 in maize (6.6 % variation over all scenarios). These results showed that the uncertainty included in the estimation of appearance dates of BBCH stages for other countries has a relatively small effect on the results of PEARL and consequentially on the decision of the pesticide risk assessment by changing only the application date. [ABSTRACT FROM AUTHOR]