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Microplastics (MPs, plastic items from 1 µm to 5 mm in size) are present in all environmental compartments. The evaluation of their concentration, fate, and spatial distribution is still a challenge for the scientific community. This concern is just debuting in developing countries, (i.e., Asia, South America, and Africa). This study deals with the MP contamination in the abiotic marine compartments of Northern Vietnam: seawater and intertidal sediments. Four sites located in the intertidal zone or near the coastline in Tonkin Bay, Vietnam were studied. A total of 16 samples (eight for each compartment) were collected in July 2020 (rainy season) and January 2021 (dry season). Anthropogenic particles (total observed fibers and fragments) were found at levels ranging from 3 to 303 particles/m3 in seawater and from 63 to 955 particles/kg dry weight in sediments. Most of these were fibers less than 300-µm long. Higher levels of seawater at the Nam Dinh site were found in the rainy season compared to the dry one. As the river flow was estimated six times higher during the rainy season than during the dry season, these results suggest the river discharge is a potential source of contamination for the coastal zone. The temporal variability was lower for the sediments than for the seawater, suggesting the long-term integration of the anthropogenic particles in this compartment. A small portion of sorted particles were analyzed by µFTIR (8.35%), and this sub-sample was only composed of fragments. Still, fragments were mostly composed of polypropylene (PP, 82%), polyethylene (PE, 9%), and polystyrene (PS, 9%). The fragment size was similar in the two studied compartments, but it was dependent on polymer types since PS fragments (140 ± 17 µm) were smaller than those made of PE (622 ± 123 µm) and PP (869 ± 905 µm). Future works should investigate the smallest fraction of MP (even nanoplastics) as well as find solutions in order to mitigate MP contamination in the marine environment. [ABSTRACT FROM AUTHOR]

Recent research on algebraic models of quasi-Nelson logic has brought new attention to a number of classes of algebras which result from enriching (subreducts of) Heyting algebras with a special modal operator, known in the literature as a nucleus. Among these various algebraic structures, for which we employ the umbrella term intuitionistic modal algebras, some have been studied since at least the 1970s, usually within the framework of topology and sheaf theory. Others may seem more exotic, for their primitive operations arise from algebraic terms of the intuitionistic modal language which have not been previously considered. We shall for instance investigate the variety of weak implicative semilattices, whose members are (non-necessarily distributive) meet semilattices endowed with a nucleus and an implication operation which is not a relative pseudo-complement but satisfies the postulates of Celani and Jansana's strict implication. For each of these new classes of algebras we establish a representation and a topological duality which generalize the known ones for Heyting algebras enriched with a nucleus. [ABSTRACT FROM AUTHOR]

In this paper, Protist algorithm (PA) and Otocyon megalotis optimization algorithm (OOA) are applied to solve the power loss lessening problem. Protist Algorithm (PA) is modelled based on the Protist's natural activities. Protist exists in moist places. The leading nutritious phase is Plasmodium, the energetic and vibrant phase of Protist. In this segment, the organic substance in Protist search for food in surroundings and conceals enzymes for digestion. Natural actions of Otocyon megalotis are emulated to design the OOA approach. In the projected OOA searching of regions in exploration, for foodstuff the Otocyon megalotis mark the prey in the space is indicated as a global exploration. Real power loss reduction and Voltage stability enhancement are the key objectives of the paper. To solve the problem, Protist algorithm (PA) and Otocyon megalotis optimization algorithm. In the course of the migration procedure, the anterior end outspreads and interconnected arterial system that authorize cytoplasm to stream inside. Then, mutation and cross-over probability are employed to augment the performance of the Protist algorithm (PA). With this integration engendering of the population is done. Mutation classes the population exploration agents (PN) in uphill order conferring to the agents appropriateness (fitness) cost. Consequently, the technique splits the organized agents into three fragments rendering to their fitness value. In which PN/3 denotes to the population possess pre-eminent (aptness) fitness values, subsequently with second pre-eminent and poorest aptness (fitness) values. Then, in this paper, Otocyon megalotis optimization algorithm (OOA) is applied for solving the Power loss lessening problem. In the subsequent segment, navigate during the haunt to seal prey previous to the hit was replicated as a local search. In exploration, the data obtained is shared to all the associates of the family unit for continued existence and growth. Examination of the nearby terrain is modelled with reference to the fitness of all entities. Most excellent entity has investigated the majority fascinating terrain and it will be shared with family unit of Otocyon megalotis. Primarily, Otocyon megalotis show that it not involved in hunting. Conversely, as soon as moving near to prey Otocyon megalotis will perform the attack in quick mode. This approach imitated and designed in the local search segment. Authenticity of the Protist algorithm (PA) and Otocyon megalotis optimization algorithm (OOA) is corroborated in 23 benchmark functions, IEEE 30, 57, 300 and 354 test systems. Power Loss reduction achieved with voltage stability enhancement. Real power loss reduction attained. Both the Protist algorithm (PA) and Otocyon megalotis optimization algorithm (OOA) performed well in solving the Power loss reduction problem. [ABSTRACT FROM AUTHOR]

In the present paper, we investigate (bo)-fragments in lattice normed spaces. After showing that every (bo)-fragment of a positive element is a fragment in the case of lattice normed vector lattices, we prove that the collection of all (bo)-fragments of a positive element forms an order complete Boolean algebra. Several examples and detailed discussions of various cases are presented. [ABSTRACT FROM AUTHOR]

As a direct result of laboratory sample manipulation required to identify microplastics (MPs) within a given matrix, some MPs are inevitably lost. The extent of this loss can be quite significant and varies greatly depending on the sample matrix, choice of protocol and target MPs in question. Defining analytical MP recovery is therefore a critical component in ensuring the quality of MP protocols. The potential relationship between particle size and recovery rate has been widely discussed but remains uncertain. To determine whether MP loss correlated with particle size, three aliquots of polyethylene fragments in the 5–50 µm size range and three aliquots of polypropylene fragments in the 50–500 µm size range, were consecutively transferred back and forth from filter to liquid. After each individual transfer the analytical recovery within specified size groups, was evaluated by applying high-resolution darkfield microscopy. Average recovery across the entire size range was estimated at 80% with a standard deviation (std. dev.) of 26%. Notably, particle coverage on filters (A%) showed a more significant impact on recovery than particle size. Maintaining A% below 5% on filters for microscopic analysis is advised to prevent excessive loss due to particle agglomeration. To determine whether the use of red polyethylene fragments in the 5–50 µm size range in combination with darkfield microscopy could potentially improve MP recovery evaluation in environmental samples, three aliquots of 0.5 g of dry brown trout muscle tissue were spiked and treated according to a relevant protocol. This size-discriminating approach accurately determined average recovery at 52% with a std. dev. of 4% and demonstrated the potential for correction of the concentration enhancement of smaller MPs resulting from particle breakup during sample pre-treatment, which would otherwise lead to overestimation of smaller size fractions. Highlights: • Recovery experiment shows no evidence of increasing microplastic loss with decreasing particle size, in the 5–500 µm range. • Investigating colored PE micro-fragments under darkfield illumination enables size-discriminating recovery estimations of microplastics ≥ 5 µm. • Particle area coverage should not exceed 5% of filters intended for microscopic analysis of microplastics (< 500 µm). • For increased relevance to environmental conditions, fragments should replace spheres or beads in microplastic recovery experiments. [ABSTRACT FROM AUTHOR]

Microplastic pollution in aquatic environments has been a ubiquitous concern in recent years, owing to their rapid production combined with poor waste management practices. However, information on freshwater microplastics in the Global South is still scarce, despite growing research on freshwater microplastics in recent years, particularly within the Global North. To help address this knowledge gap, we studied water and sediment microplastic dynamics along a subtropical river system, i.e. Crocodile River around the Nelspruit City area (South Africa), across three different seasons (i.e. cool-dry, hot-dry, hot-wet) using a combination of diversity indices and multivariate analyses. Microplastics were more abundant during the cool-dry season in the surface water samples (mean 1058 particles m−3) and high during the hot-dry season (mean 568 particles kg−1 dwt) in the sediment samples. The hot-wet season had a low particle density in both surface water (mean 625 particles m−3) and sediments (mean 86 particles kg−1 dwt) samples. Microplastic shapes were dominated by fibres and fragments, with the colour scheme dominated by transparent, blue, and black. The abundance of microplastics was positively correlated with pH and resistivity, and negatively with river flow. Wastewater was attributed as a primary source of microplastics, particularly because of the observed dominant fibre microplastics, usually released during laundry. Our results suggest that Crocodile River and its tributaries are temporary sinks of microplastics during periods of low rainfall. Implications of this pollution are far-reaching, including effects on residents who are dependent on the Crocodile River as a source of drinking water and aquatic biota which may be exposed to these pollutants. [ABSTRACT FROM AUTHOR]

Microplastics (MPs) are pollutants of emerging concern that have been reported in terrestrial and aquatic ecosystems as well as in food items. The increasing production and use of plastic materials have led to a rise in MP pollution in aquatic ecosystems. This review aimed at providing an overview of the abundance and distribution of MPs in riverine ecosystems and the potential effects posed on macroinvertebrates. Microplastics in riverine ecosystems are reported in all regions, with less research in Africa, South America, and Oceania. The abundance and distribution of MPs in riverine ecosystems are mainly affected by population density, economic activities, seasons, and hydraulic regimes. Ingestion of MPs has also been reported in riverine macroinvertebrates and has been incorporated in caddisflies cases. Further, bivalves and chironomids have been reported as potential indicators of MPs in aquatic ecosystems due to their ability to ingest MPs relative to environmental concentration. Fiber and fragments are the most common types reported. Meanwhile, polyethylene, polypropylene, polystyrene, polyethylene terephthalate (polyester), polyamide, and polyvinyl chloride are the most common polymers. These MPs are from materials/polymers commonly used for packaging, shopping/carrier bags, fabrics/textiles, and construction. Ingestion of MPs by macroinvertebrates can physically harm and inhibit growth, reproduction, feeding, and moulting, thus threatening their survival. In addition, MP ingestion can trigger enzymatic changes and cause oxidative stress in the organisms. There is a need to regulate the production and use of plastic materials, as well as disposal of the wastes to reduce MP pollution in riverine ecosystems. [ABSTRACT FROM AUTHOR]

Medieval bindings fragments have become increasingly interesting to Humanities researchers as sources for the textual and material history of medieval Europeans. Later book binders used these discarded and repurposed pieces of earlier medieval manuscripts to reinforce the structures of other manuscripts and printed books. That many of these fragments are contained within and obscured by decorative bindings that cannot be dismantled ethically has limited their discovery and description. Although previous attempts to recover these texts using IRT and MA-XRF scanning have been successful, the extensive time required to scan a single book, and the need to modify or create specialized IRT or MA-XRF equipment for this method are drawbacks. Our research proposes and tests the capabilities of medical CT scanning technologies (commonly available at research university medical schools) for making visible and legible these fragments hidden under leather bindings. Our research team identified three sixteenth-century printed codices in our university libraries that were evidently bound in tawed leather by one workshop. The damaged cover of one of these three had revealed medieval manuscript fragments on the book spine; this codex served as a control for testing the other two volumes to see if they, too, contain fragments. The use of a medical CT scanner proved successful in visualizing interior book-spine structures and some letterforms, but not all of the text was made visible. The partial success of CT-scanning points to the value of further experimentation, given the relatively wide availability of medical imaging technologies, with their potential for short, non-destructive, 3D imaging times. [ABSTRACT FROM AUTHOR]

Pollen grains are released from plants and rupture, releasing pollen grain fragments referred to as subpollen particles (SPPs). This study is a laboratory evaluation of live oak, Quercus virginiana, to determine the environmental conditions needed to emit SPPs and measure the concentration of SPPs produced. To represent conventional SPP release, live oak branches were exposed to high relative humidity (> 95%), followed by reduced relative humidity (73.5%-76.3%) and wind (up to 1.8 m s−1). In contrast, wind-driven SPP release experiments were conducted by exposing branches to constant relative humidity while cycling fans used to simulate winds. Wind-driven experiments produced maximum SPP concentrations as high as 3.3 × 102 ± 2.7 × 102 SPPs per cm3. The maximum SPP emissions during conventional SPP release experiments were as high as 7.3 × 101 ± 3.4 × 101 SPPs per cm3. The total number of SPPs emitted during conventional SPP release experiments was not significantly different from the SPP emissions during wind-driven SPP release experiments at a 5% significance level. The concentration of SPPs generated from pollen grains was used to calculate SPP emission factors. SPP emission factors were determined to be between 1.6 × 104 and 9.0 × 104 SPPs per pollen grain and between 4.7 × 1012 and 2.2 × 1015 SPPs per m2. These results indicate that SPPs represent a significant source of cloud-forming aerosol and have the ability to impact respiratory health. [ABSTRACT FROM AUTHOR]

We identified and characterized microplastics (MPs) in the gastrointestinal tract (GT), gills (GI), and exoskeleton (EX) of Litopenaeus vannamei in a coastal lagoon from the SE Gulf of California. The most common MPs were fibers and fragments with an average size of 403 ± 296 μm, in which the transparent and blue colors predominated. The abundance (items/g as wet weight (ww)) in the GT, GI, and EX was 114.7 ± 33.2, 13.7 ± 5.3 and 3.0 ± 0.5, respectively. The abundance of MPs per shrimp was 13.3 ± 1.1, while the abundance per individual (ww) was 0.9 ± 0.2 MPs/g. Considering the consumption of shrimp in Mexico, MP abundance, and shrimp consumption (discarding GI and EX), we estimated MP ingestion as 280 items/person/year. The results from this study can be used as background information for future MP biomonitoring in shrimp species of ecological and commercial importance. [ABSTRACT FROM AUTHOR]

Solar filaments are distinct strip-like structures observed in chromospheric H α images. Filament eruptions, flares, and coronal mass ejections (CMEs) can be regarded as the same physical process of releasing magnetic energy at different times and solar atmosphere heights. It is very important to detect filaments for forecasting flares and CMEs. This article proposes a new solar-filament detection and classification method based on CondInst; a deep-learning model. A data set of solar filaments is built, including ten thousand filaments. To distinguish filaments that consist of only a single connected dark region and filaments that are broken into several fragments, the filaments are classified into isolated filaments and non-isolated filaments. The mean precision, recall, A P , and F1 obtained using the proposed method are 90.83 % , 83.88 % , 82.86 % , and 87.22 % , respectively. The results show that the method performs well in detecting and classifying isolated and non-isolated filaments, especially in solving the fragments problem of how to detect a filament that is broken into several fragments. The method also has good performance in handling various images, even with existing uneven brightness or low contrast. The precision of filament masks still needs to be improved in the future. [ABSTRACT FROM AUTHOR]

The red algal genus Asparagopsis produces secondary metabolites that when fed to ruminants reduce methane production by up to 98%. However, cultivation methods for Asparagopsis are nascent and fundamental information on reproduction, which is essential for large-scale cultivation, is lacking. In this study we examined asexual propagation in Asparagopsis armata, the regrowth of fragments and mechanisms of attachment to assess the potential for fragments to be used in sea-based cultivation. Asparagopsis armata gametophytes grow specialised structures, barbs, that hook fragments onto substrata. Surveys revealed barbs were abundant occurring at ~ 1 barb every 3–4 cm on gametophyte branches. Barbs did not regrow, but fronds did, either when attached to a barb or on their own. In contrast, fronds doubled in size with most developing barbs within 4 weeks. Barbs were, however, critical for the reattachment of fragments: barbs attached to substrata at four times the rate of frond fragments without barbs and they also attached in higher proportions to mussel rope than polypropylene rope, and two types of net. Utilising fragmentation for the propagation of A. armata gametophytes in sea-based cultivation requires that fragments can attach to a substratum and regrow once attached. We have shown that A. armata fragments in Tasmania require barbs for attachment and frond tissue for growth, which has implications for cultivation. Optimising fragmentation, attachment and out-planting methods are important future steps in establishing fragmentation as a method for sea-based cultivation in A. armata. [ABSTRACT FROM AUTHOR]

Microplastics are ubiquitous in marine systems, but their effects on coral physiology are still largely unknown. This study aimed to determine if exposure to a range of sizes of microplastic (10–100 µm) over a 4-week period affected selected physiological processes of healthy and moderately bleached corals. Two separate feeding experiments in which similar sized healthy and bleached Anomastraea irregularis and Pocillopora verrucosa nubbins from the south coast of KwaZulu-Natal, South Africa (30.3167° S, 30.7333° E) were fed either 0.8 mg of zooplankton only or a mix (a combination of 0.4 mg polypropylene fragments, 0.4 mg polyester fibres, and 0.8 mg zooplankton) were conducted in closed chambers for a period of 28 nights during May and June 2018. No significant differences in the physiology (ingestion, respiration, photosynthetic and growth rates) and tissue composition (Symbiodiniaceae, chlorophyll a and lipid contents) were found between corals fed the mix and those fed zooplankton only (p > 0.05). An egestion analysis revealed that both healthy and bleached A. irregularis and P. verrucosa egested the majority of the ingested microplastics after 18 h. This study shows that corals can ingest different types of microplastics but are also able to egest them over a few hours, preventing any detrimental effects. [ABSTRACT FROM AUTHOR]

Background: Structure-based drug repositioning has emerged as a promising alternative to conventional drug development. Regardless of the many success stories reported over the past years and the novel breakthroughs on the AI-based system AlphaFold for structure prediction, the availability of structural data for protein–drug complexes remains very limited. Whereas the chemical libraries contain millions of drug compounds, the vast majority of them do not have structures to crystallized targets,and it is, therefore, impossible to characterize their binding to targets from a structural view. However, the concept of building blocks offers a novel perspective on the structural problem. A drug compound is considered a complex of small chemical blocks or fragments, which confer the relevant properties to the drug and have a high proportion of functional groups involved in protein binding. Based on this, we propose a novel approach to expand the scope of structure-based repositioning approaches by transferring the structural knowledge from a fragment to a compound level. Results: We fragmented over 100,000 compounds in the Protein Data Bank (PDB) and characterized the structural binding mode of 153,000 fragments to their crystallized targets. Using the fragment's data, we were able to artificially reconstruct the binding mode of over 7,800 complexes between ChEMBL compounds and their known targets, for which no structural data is available. We proved that the conserved binding tendency of fragments, when binding to the same targets, highly influences the drug's binding specificity and carries the key information to reconstruct full drugs binding mode. Furthermore, our approach was able to reconstruct multiple compound-target pairs at optimal thresholds and high similarity to the actual binding mode. Conclusions: Such reconstructions are of great value and benefit structure-based drug repositioning since they automatically enlarge the technique's scope and allow exploring the so far 'unexplored compounds' from a structural perspective. In general, the transfer of structural information is a promising technique that could be applied to any chemical library, to any compound that has no crystal structure available in PDB, and even to transfer any other feature that may be relevant for the drug discovery process and that due to data limitations is not yet fully available. In that sense, the results of this work document the full potential of structure-based screening even beyond PDB. [ABSTRACT FROM AUTHOR]

Microplastics are now found throughout the world's oceans, and although many organisms ingest microplastics, less is known about how plastics in seawater may affect key processes such as feeding rate, growth, and survival. We used a series of laboratory experiments to test whether microplastics in seawater affected the feeding rates of larvae of the California Grunion, Leuresthes tenuis. In addition, we tested whether trophic transfer of microplastics from zooplankton to larval fish can occur and affect growth and survival of fish. We measured feeding rates of grunion larvae at various concentrations of 75–90 µm and 125–250 µm polyethylene microplastics and under both still water and turbulent conditions. In these experiments, exposure to microplastics had modest effects on feeding rates, though responses may be somewhat complex. Low concentrations of microplastics increased feeding rates compared to the control, but at higher concentrations, feeding rates were indistinguishable from those in the control group, though effects were small compared to natural variation in feeding rates among individual fish. Experiments to test for trophic transfer of microplastics revealed that grunion larvae that were fed brine shrimp exposed to high concentrations of microplastics had lower growth rates and elevated mortality rates. Overall, our results suggest that the direct effects of microplastics on feeding rates of California Grunion during the early larval phase are minor, while the trophic transfer of microplastics from zooplankton to larval fish may have significant effects on their growth and survival. [ABSTRACT FROM AUTHOR]

Detailed particle breakage adjacent to a pile has great influence on the settlement and bearing capacity of a pile foundation. Before the pile test, coral sand was divided into different grain-size groups and dyed in different colors, then mixed as the ground soil. After pile penetration, the sand around the pile was divided into many zones and sampled. Grains in different colors in each size range of each sample were discerned quantitatively. Results show that the settlement curve dropped fast and the skin friction of pile was small due to the obvious particle breakage. In each zone, the actual particle breakage in each size range was different from the change in relative mass percentage, and the lost of angular edges is the dominant type of particle breakage under the bottom pressure of pile. The index Bag, excluding the interference effect of size overlap between fragments and unbroken grains in each size range, was slightly larger than Bg for most zones around the pile. The breakage-zone was limited to 1.5 times of the pile diameter at the radial direction and 2.5 times at the depth direction, which is much deeper than that in silica sand. Particle breakage at some distance from pile bottom is larger than that at the very bottom of the pile due to the shearing effect in the sand. Detailed particle breakage around the pile is useful in studying the interaction between the pile and crushable granular soil. [ABSTRACT FROM AUTHOR]

The paper contains a systematic study of the lateral partial order ⊑ in a Riesz space (the relation x ⊑ y means that x is a fragment of y) with applications to nonlinear analysis of Riesz spaces. We introduce and study lateral fields, lateral ideals, lateral bands and consistent subsets and show the importance of these notions to the theory of orthogonally additive operators, like ideals and bands are important for linear operators. We prove the existence of a lateral band projection, provide an elegant formula for it and prove some properties of this orthogonally additive operator. One of our main results (Theorem 7.5) asserts that, if D is a lateral field in a Riesz space E with the intersection property, X a vector space and T 0 : D → X an orthogonally additive operator, then there exists an orthogonally additive extension T : E → X of T 0 . The intersection property of E means that every two-point subset of E has an infimum with respect to the lateral order. In particular, the principal projection property implies the intersection property. [ABSTRACT FROM AUTHOR]

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Background. Tropical dry deciduous forests are the most vulnerable ecosystems for fragmentation. Satellite remote sensing data (of various resolutions and temporal availability) helps to study the forest fragmentation at local, regional and global scale. Spatial distribution of fragments at regional scale would provide insight into restoration and connectivity among the fragments, such that wildlife habitat can be protected. Results.: In the present study the forests of Mirzapur district, Uttar Pradesh were studied using LANDSAT- OLI (2017) satellite data and the forest fragmentation was quantified using the fragmentation metrics. The forest cover of the district (17.27% of the total geographic area) was delineated into four classes, very dense forest, dense forest, medium dense forest and open forest. Various fragments of size class were also defined in each forest cover. Fragments of size <2, 2–10, 10–50, 50–100, 100–500, and >600 ha were analysed. Presence of Sloth Bear and wildlife was noted in the fragmented forest based on pieces of evidence like scats, termite mounds, and dens. Conclusion.: In this study, it was observed that the number of fragments in category <2 ha are more in each forest cover class. The suitable wildlife habitat was found to be very dense and dense forest. Thus the need of the hour is to protect these fragmented forests and connect these fragments to allow better movement of large mammals such that their population can thrive. The study also acts as a bench mark in using geospatial technology to define fragmentation. The focus should be on medium dense and open forests. Very dense and dense forests act as refugia which should be protected from further destruction. [ABSTRACT FROM AUTHOR]

In this study, rectangular prismatic coarse-grain granites were analyzed through an application of a modified true-triaxial rockburst testing system. Various loading rates were considered in a process in which one face was kept free and loading conducted on the other five faces. Using a proposed surface energy per unit area measurement method, the energy dissipation due to the formation of rock fragments during the rockburst process was quantitatively analyzed. The experimental results show that rockburst occurrence depends on several conditions, including — specifically the tangential loading rate exceeding a certain threshold, the presence of considerable amounts of stored strain energy, the dissipation of energy through rock splitting on the free face, and the shear failure in the potential rockburst pit. With increases in the loading rate from 0.5 to 4.0 MPa/s, the fragmentation and energy dissipation of fragments decline linearly. Lamellar coarse fragments are found to be primarily induced by tension failure from the rockburst pit surface. Blocky medium, fine fragments and white powdery tiny particles are mainly induced by shear failure from the rockburst pit interior. Under various loading rates, the dissipated energy of fragments induced by shear is more than 90% of the total dissipated energy. [ABSTRACT FROM AUTHOR]

In recent years, the occurrence of microplastics in the aquatic environment has gathered increasing scientific interest. Several studies have shown that the ingestion of microplastics may negatively influence the physiology of marine organisms having different feeding strategies, particularly in those species which cannot discriminate between food sources. Recent studies highlighted the potential for such particles to accumulate in the food web, posing risks to human health via the consumption of seafood. Furthermore, early findings also indicated the role of microplastics as vectors of chemical pollutants either used as additives during synthesis of the plastics or adsorbed directly from seawater, i.e., PAHs, PCB, and surfactants. Despite the importance of microplastics in adsorption and transport of hydrophobic pollutants, little is known about their distribution and accumulation in marine food webs, or their direct and indirect harmful effects. The Adriatic Sea represents a semi-enclosed basin with a low water recirculation rate and high anthropogenic pressures associated with unsustainable fishing and inputs of contaminants. The body burden, accumulation rates, polymer composition, and recurring morphotypes of microplastics in native blue mussels (M. galloprovincialis) were examined. Organisms collected offshore were compared to those collected in coastal areas. Microplastics were recovered from the soft tissues of all analyzed mussels. Coastal organisms showed a load of 1.06–1.33 fragments g−1 (wet weight) and 0.62–0.63 fibers g−1 (wet weight) while offshore organisms showed an accumulation of 0.65–0.66 fragments g−1 (wet weight) and 0.24–0.35 fibers g−1 (wet weight). The size class distribution revealed a marked prevalence of smaller particles (20 μm to 40 μm range) and the most recurring polymer type in analyzed organisms was PE followed by PP, PET, and equal amounts of PS, PLY, and PVC. A significant site-, time-, and oceanographic-related distribution trend was observed. Based on the findings presented here, there is a clear need to implement a seafood safety monitoring program to better understand actual human health–related risks. [ABSTRACT FROM AUTHOR]

Waterpipes have been used to smoke tobacco and other substances by the indigenous people of Africa and Asia for at least four centuries. Waterpipe smoking causes different genotoxic effects. The evaluation of chromosome aberrations (CAs) is one of the standard methods used for assessing the DNA damage in human subjects. The aim of this study was to determine whether waterpipe smoking increases the frequency of different types of CAs in the peripheral blood lymphocytes of young waterpipe smokers ( n = 25 ) compared with non-smokers ( n = 25 ) in Jordan. Twenty-five metaphases were scored and evaluated for chromosome breakage, fragment and gap for each individual. Chromosomal breakage ratios were detected to be 2.53 ± 1 and 0.576 ± 0.64 in the waterpipe smokers and non-smokers groups, respectively. The fragments ratios were 2.19 ± 0.9 and 0.72 ± 0.05 , and the gaps ratios were 2.15 ± 0.67 and 0.6 ± 0.5 in the waterpipe smokers and non-smokers groups ( p < 0.0001 ), respectively. The results of the study revealed a significant increase in the frequencies of different types of CAs in waterpipe smokers compered to non-smokers, suggesting that smoking a waterpipe may cause genotoxic effects. [ABSTRACT FROM AUTHOR]

Wee1 is cell cycle protein comprising a kinase domain and is a validated cancer target. We have designed molecules with variable tricyclic core scaffolds [6-6-5] system and extended them based on the chemical space available in the active site of Wee1 kinase using de novo drug design. The core scaffolds and linking fragments were extracted from pharmacophore-based virtual screening of ZINC and PubChem databases and Ludi library. These molecules bind the hinge region of kinase active site and form hydrogen bonds as confirmed from molecular docking, molecular dynamics simulations, and MM_PBSA calculations. When compared with reference inhibitors, AZD1775 and PHA-848125, the de novo designed molecules also show good docking scores and stability, retained non-covalent interactions, and high binding free energies contributed from active site residues. [ABSTRACT FROM AUTHOR]

The group composition of hydrocarbons (HC) and hetero compounds in the products of stepwise thermolysis of asphaltenes from crude oil of the Usa oilfield at temperatures of 120, 230, 370, 500 and 750°C has been studied. The volatile thermolysis products formed at each step of the process have been studied by gas chromatography-mass spectrometry. It has been found that the main products of stepwise thermolysis of asphaltene molecules are alkylbenzenes (AB) and saturated aliphatic hydrocarbons (SAH), aromatic fragments obtained at 370°C are mainly separate structural blocks of asphaltene molecules, and benzothiophenes (BT) predominate over dibenzothiophenes (DBT) as structural units of asphaltene molecules. It has been shown that with an increase in the process temperature, the alkylbenzenes/saturated aliphatic hydrocarbons ratio (AB/SAH + Alkenes) increases by a factor of 6 to 7; the phenanthrene/alkylbenzenes (PN/AB) ratio and the polycyclic aromatic hydrocarbons/alkylbenzenes (PAH/AB) ratio decrease by ten- and twofold, respectively; and the naphthalenes/alkylbenzenes (NP/AB) ratio increases by two times. [ABSTRACT FROM AUTHOR]

Operative fracture treatment has become established worldwide with four principles: anatomical reduction, stable internal fixation, preservation of blood supply and early active pain-free mobilization. The paramount importance of preservation of the blood supply to the bone fragments was recognized from the very beginning and is still just as valid as early and pain-free mobilization. Also still valid is striving for the best possible anatomical reduction in joints but in diaphyseal fractures it was recognized that anatomical reduction, especially in multifragmentary fractures, is not possible without considerable impairment of the bood supply. In multifragmentary fractures the correct positioning of the main proximal fragment to the main distal fragment is decisive, where bone wedges and comminuted fracture areas should be bridged and not fixed. The aim of absolute stability, which was previously strived for, is nowadays only valid for joints and diaphyseal fractures are currently treated by osteosynthesis with relative stability, which results in healing via calluses. The failure rates for diaphyseal fractures could be considerably reduced by changing the target from absolute to relative stability and preservation of the blood supply to the fragments. [ABSTRACT FROM AUTHOR]

A graphene nanoflake (GNF) is a polycyclic aromatic hydrocarbon (PAH) with a huge two-dimensional π-conjugated carbon material in which a central benzene ring is surrounded by identical benzene-type rings through infinite alternant method. In this paper, we explore the structure-aromaticity relationship of the GNFs and the GNFs with hollow sites (GNFHs) by combining the nucleus-independent chemical shifts (NICS) with the anisotropy of the current induced density (ACID). Firstly, the benzene is a typical aromatic molecule (NICS = −9.671 ppm), GNFs 1- 6 is darned with benzene and the corresponding GNFHs 1′- 6′. Secondly, the NICS values of GNFs 1- 6 alternately vary: −1.214 ( 1) > −13.847 ( 2) < −2.662 ( 3) > −14.530 ( 4) < −3.932 ( 5) > −13.978 ( 6) ppm, the GNFs ( 2, 4, 6) with even fragments of annulene have larger aromaticity than that of GNFs ( 1, 3, 5) with odd fragments of annulene. Significantly, the NICS values of GNFs 1- 6 can also be fragment analyzed by the NICS values and ACID of benzene and corresponding GNFHs 1′- 6′. The NICS values for GNFs ( 2, 4, 6) can be roughly estimated by the NICS value of benzene minus the NICS value of the GNFHs ( 2′, 4′, 6′), respectively. The NICS values for GNFs ( 1, 3, 5) can be roughly estimated by the NICS value of the GNFHs ( 1′, 3′, 5′) minus the NICS value of benzene, respectively. We hope that the present work can provide a simple and reliable method for the rational design of the GNF with aromaticity, which may be used to understand the origin of the graphene nanoflake aromatic properties. [ABSTRACT FROM AUTHOR]

Breast cancer is the most frequent cancer reported in women, being responsible for hundreds of thousands of deaths. Chemotherapy has proven to be effective against this malignant neoplasm depending on different biological factors such as the histopathology, grade, and stage, among others. However, breast cancer cells have become resistant to current chemotherapeutic regimens, urging the discovery of new anti-breast cancer drugs. Computational approaches have the potential to offer promising alternatives to accelerate the search for potent and versatile anti-breast cancer agents. In the present work, we introduce the first multitasking (mtk) computational model devoted to the in silico fragment-based design of new molecules with high inhibitory activity against 19 different proteins involved in breast cancer. The mtk-computational model was created from a dataset formed by 24,285 cases, and it exhibited accuracy around 93% in both training and prediction (test) sets. Several molecular fragments were extracted from the molecules present in the dataset, and their quantitative contributions to the inhibitory activities against all the proteins under study were calculated. The combined use of the fragment contributions and the physicochemical interpretations of the different molecular descriptors in the mtk-computational model allowed the design of eight new molecular entities not reported in our dataset. These molecules were predicted as potent multi-target inhibitors against all the proteins, and they exhibited a desirable druglikeness according to the Lipinski's rule of five and its variants. [ABSTRACT FROM AUTHOR]

The Īśvarapratyabhijñā treatise-an important philosophical text composed in Kashmir in the 10th century CE by the Śaiva nondualist Utpaladeva-remains partly unavailable to date: a crucial component of this work, namely the detailed commentary ( Vivṛti or Ṭīkā) in which Utpaladeva explained his own verses, is considered as almost entirely lost, since only a small part of it has been preserved in a single, very incomplete manuscript remarkably edited and translated by Raffaele Torella. However, our knowledge of the Vivṛti is quickly expanding: many additional fragments have recently come to light. The article gives an overview of these new findings while highlighting the most interesting of them, i.e. the discovery of the lengthiest Vivṛti fragment known to date in the margins of a manuscript containing Abhinavagupta's Vivṛtivimarśinī. It also provides an edition and translation of the beginning of this fragment. [ABSTRACT FROM AUTHOR]

The 'Up-and-down' theorem which describes the structure of the Boolean algebra of fragments of a linear positive operator is the well known result in operator theory. We prove an analog of this theorem for a positive abstract Uryson operator defined on a vector lattice and taking values in a Dedekind complete vector lattice. This result is used to prove a theorem of domination for order narrow positive abstract Uryson operators from a vector lattice E to a Banach lattice F with an order continuous norm. [ABSTRACT FROM AUTHOR]

This experiment demonstrates the large potential of macro-XRF imaging for the visualization of fragments of medieval manuscripts hidden in early-modern bookbindings. The invention of the printing press in the fifteenth century made manuscripts obsolete and bookbinders started recycling their strong parchment leaves to reinforce bindings of printed books. One in roughly every five early-modern books contains a fragment of a medieval manuscript hidden underneath the bookbinding. Systematically investigating these fragments will provide scholars with valuable information about transmission and variant readings of medieval texts. Four case studies were scanned with a Bruker M6 Jetstream mobile XRF scanner. We were able to visualize hidden texts underneath black paint, paper and parchment at such a high resolution that they could be read and dated. One of the findings was an early twelfth-century excerpt of a text by the Venerable Bede in a sixteenth-century bookbinding. In addition, we were able to separately visualize the lower and upper text of a famous palimpsest. The main limitation of the current set-up is the scanning time, which took anywhere between 6 and 66 h. In order to systematically employ macro-XRF for researching medieval fragments, the scanning time needs to be decreased. Nonetheless, this experiment shows that the macro-XRF technique is extremely suitable for visualizing fragments of medieval manuscripts in a non-destructive way in order to read, date and localize them. [ABSTRACT FROM AUTHOR]

The efficiency of methods of the spectral-spatial classification of similarly looking types of vegetation on the basis of hyperspectral data of remote sensing of the Earth, which take into account local neighborhoods of analyzed image pixels, is experimentally studied. Algorithms that involve spatial pre-processing of the raw data and post-processing of pixel-based spectral classification maps are considered. Results obtained both for a large-size hyperspectral image and for its test fragment with different methods of training set construction are reported. The classification accuracy in all cases is estimated through comparisons of ground-truth data and classification maps formed by using the compared methods. The reasons for the differences in these estimates are discussed. [ABSTRACT FROM AUTHOR]

The Boolean algebra of fragments of a positive abstract Uryson operator recently was described in M. Pliev (Positivity, doi:, 2016). Using this result, we prove a theorem of domination for AM-compact positive abstract Uryson operators from a Dedekind complete vector lattice E to a Banach lattice F with an order continuous norm. [ABSTRACT FROM AUTHOR]

Abstract: The aim of this study was to calculate the total length of the humerus and identify the sex from its fragments in Egyptians. One hundred and fifty dry adult right humeri (75 male and 75 female) were studied. The humeri were divided into seven fragments according to specific anatomical landmarks. Data obtained was subjected to descriptive statistical analysis. The longest fragmentary portion revealed a good result with closest proximity to the total length of humerus. All fragments showed significant sexual differences ( P < 0.001) between males and females except H2. Total length of humerus revealed the highest percentage of accuracy (93.3%) followed by H4 (86.7%) and H7 (83.3%) for sex identification. Finally, from measurements of different humeral fragments in Egyptian population; the length of the humerus can be estimated and the sex can be identified. [ABSTRACT FROM AUTHOR]

The evolution of dislocation substructures formed in polycrystalline Cu−Al and Cu−Mn alloys undergoing large plastic deformations is studied, using transmission electron microscopy. Microband and fragmented substructures are examined. The Al and Mn alloying element concentrations for which the substructures are formed have been found. The mechanisms involved in the formation of the substructures during the substructural evolution in the alloys subjected to deformation have been revealed. Parameters describing the substructures under study have been measured. The dependence of the parameters on the flow stress has been established. [ABSTRACT FROM AUTHOR]

Dynorphin A 1-17 (DYN A) is an endogenous neuropeptide that is of interest due to its diverse roles in analgesia, inflammation and addiction. Upon release, DYN A is subject to metabolism by a range of enzymes and its biotransformation is dependent on the site and environment into which it is released. In this study, we investigated the biotransformation of DYN A in rat inflamed tissue at pH 7.4 and 5.5, in rat serum and in trypsin solution. DYN A-porcine was incubated at 37 °C in each matrix over a range of incubation periods. The resultant fragments were separated using a C4 column and detected by mass spectrometry using total ion current mode. Incubation of DYN A in trypsin solution and in rat serum resulted in 6 and 14 fragments, respectively. Incubation in inflamed rat paw tissue occasioned 21 fragments at pH 7.4 and 31 fragments at pH 5.5. Secondary breakdown of some larger primary fragments was also observed in this study. [ABSTRACT FROM AUTHOR]

Beta endorphin (β-END) is recognised as one of the most significant endogenous neuropeptides, responsible for a wide range of biological activities in the body. However, within the body β-END is exposed to hydrolysis by a variety of enzymes. In this study, we investigated the metabolism and fragmentation pattern of β-END in rat inflamed tissue, in rat serum and in trypsin solution. β-END (1-31)-rat was incubated at 37 °C in each matrix for different incubation times. The resultant fragments were separated using a C4 column and detected by mass spectrometry using total ion current mode. Structural information for the fragments was elucidated using tandem mass spectrometry. Incubation of β-END (1-31)-rat in trypsin solution and in rat serum resulted in 8 and 13 fragments, respectively. Incubation in inflamed rat paw tissue resulted in 22 fragments at pH 7.4 and 26 fragments at pH 5.5. Some of these fragments were common to both pH values. The degradation of β-END (1-31)-rat in inflamed tissue at pH 5.5 was faster than that at pH 7.4. Secondary fragmentation of some larger primary fragments was also observed in this study. [ABSTRACT FROM AUTHOR]

The increasing resistance of several phytopathogenic fungal species to the existing agrochemical fungicides has alarmed to the worldwide scientific community. There is no available methodology to predict in an efficient way if a new fungicide will have resistance risk due to fungal species which cause considerable crop losses. In an attempt to overcome this problem, a multi-resistance risk QSAR model, based on substructural descriptors was developed from a heterogeneous database of compounds. The purpose of this model is the classification, design, and prediction of agrochemical fungicides according to resistance risk categories. The QSAR model classified correctly 85.11% of the fungicides and the 85.07% of the inactive compounds in the training series, for an accuracy of 85.08%. In the prediction series, the percentages of correct classification were 85.71 and 86.55% for fungicides and inactive compounds, respectively, with an accuracy of 86.39%. Some fragments were extracted and their quantitative contributions to the fungicidal activity were calculated taking into consideration the different resistance risk categories for agrochemical fungicides. In the same way, some fragments present in molecules with fungicidal activity and with negative contributions were analyzed like structural alerts responsible of resistance risk. [ABSTRACT FROM AUTHOR]

Diabetic cardiomyopathy (DCM) is a clinical condition, diagnosed when ventricular dysfunction develops in diabetic patients without coronary atherosclerosis and hypertension. Intensive studies on pathogenesis of DCM show PKCβII as one of the mediators, responsible for developing DCM. 2D-QSAR (HQSAR) and 3D-QSAR (CoMSIA) studies were performed on a dataset of 42 anilino-monoindolylmaleimides acting as PKCβII selective inhibitors. Among the different alignment strategies used for CoMSIA study FlexS was found to be the best alignment method. Conformational search was performed for a few molecules to obtain the best model. CoMSIA analysis gave information about sites of favorable substitutions and steered us to assume that alkyl amine substitution on the pharmacophore would be a favorable substituent for improving the biological activity. From HQSAR studies we could extrapolate the presence of tertiary acceptor group may probably be responsible for increase in the activity whereas occurrence of cyclic ring structures would lead to decrease in the activity. [ABSTRACT FROM AUTHOR]

The chemical universe database GDB-13, which enumerates 977 million organic molecules up to 13 atoms of C, N, O, S and Cl following simple chemical stability and synthetic feasibility rules, represents a vast reservoir for new fragments. GDB-13 was classified using the MQN-system discussed in the preceding paper for the analysis of PubChem fragments. Two hundred and fifty-five subsets of GDB-13 were generated by the combinatorial use of eight restrictive criteria, including fragment-like ('rule of three') and scaffold-like (no acyclic carbon atoms) filters. Virtual screening for analogs of 15 commercial drugs of 13 non-hydrogen atoms or less shows that retrieving MQN-neighbors of a query molecule from GDB-13 or its subsets provides on average a 38-fold enrichment in structural analogs (Daylight-type substructure fingerprint Tanimoto T > 0.7), and a 75-fold enrichment in shape-similar analogs (ROCS TanimotoCombo score > 1.4). An MQN-searchable version of GDB-13 is provided at . Graphical Abstract: [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

The 4.5 million organic molecules with up to 20 non-hydrogen atoms in PubChem were analyzed using the MQN-system, which consists in 42 integer value descriptors of molecular structure. The 42-dimensional MQN-space was visualised by principal component analysis and representation of the (PC1, PC2), (PC1, PC3) and (PC2, PC3) planes. The molecules were organized according to ring count (PC1, 38% of variance), the molecular size (PC2, 25% of variance), and the H-bond acceptor count (PC3, 12% of variance). Compounds following Lipinski's bioavailability, Oprea's lead-likeness and Congreve's fragment-likeness criteria formed separated groups in MQN-space visible in the (PC2, PC3) plane. MQN-similarity searches of the 4.5 million molecules (see the browser available at ) gave significant enrichment factors for recovering groups of fragment-sized bioactive compounds related to ten different biological targets taken from Chembl, allowing lead-hopping relationships not seen with substructure fingerprint similarity searches. The diversity of different compound series was analyzed by MQN-distance histograms. Graphical Abstract: [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

This is an overview of the present-day versions of monadology with some applications to vector lattices and linear inequalities. Two approaches to combining nonstandard set-theoretic models are sketched and illustrated by order convergence, principal projection, and polyhedrality. [ABSTRACT FROM AUTHOR]

We present the results of experimental studies of the process of fission of Bi nuclei into three mass-comparable fragments by bremsstrahlung photons with maximum energies of 2 GeV and 4.5 GeV with use of nuclear photoemulsion implanted with bismuth nuclei. We compare the results with those obtained with proton beams. [ABSTRACT FROM AUTHOR]

Human-induced habitat fragmentation might seriously affect behavioural patterns and the survival of species whose ecological requirements strongly depend on specific environmental conditions. We compared the genetic structure and dispersal patterns of 2 populations of Alouatta caraya (Plathyrrhini, Atelidae) to understand how habitat reduction and fragmentation affect gene flow in this species. We sampled individuals from 7 groups living in continuous forest (CF, n = 46, 22 males and 24 females), and 11 groups that inhabit a fragmented forest (FF, n = 50, 24 males and 26 females). FST values based on 11 microsatellite loci showed a recent genetic differentiation among groups in the FF. In contrast, the CF showed no differentiation among groups. Further, FST values between sexes, as well as kinship relationships, also exhibited differences between habitats. In the CF, both males and females disperse, leading to nondifferentiated groups composed of adults that are not close relatives. Conversely, in the FF, some groups are differentiated, males disperse more than females, and groups are composed of closely related adult females. Our results suggest that habitat fragmentation modifies the dispersal patterns of black-and-gold howlers. These differences between habitats may reflect a reduced gene flow, providing genetic evidence that suggests that habitat fragmentation severely limits the howler's ability to disperse. An increasing level of isolation due to uncontrolled deforestation may cause similar loss of genetic diversity on other arboreal primates, and nonprimates that depend on forest continuity to disperse, reducing their abilities to cope with environmental changes. [ABSTRACT FROM AUTHOR]

Split questions such as What tree did John plant, an oak? contain a wh-question part and a tag. Drawing on Spanish, Basque and English data, this article argues that these two parts of a split question are independent clauses. The tag is in fact an elliptical non- wh-question, where ellipsis is licensed in the same way as in other sentence fragments. I provide detailed argumentation that the tag involves movement of a correlate of the wh-phrase, followed by ellipsis of the remnant, thus contributing to the growing body of evidence that sentence fragments (sluicing, fragment answers, etc.) are syntactically full clauses. The syntax proposed provides a simple account of the intonation patterns found in split questions and of their semantics. Furthermore, it is argued that the only existing alternative analysis of split questions cannot account for many of the properties of this construction. [ABSTRACT FROM AUTHOR]

We have developed a method that uses energetic analysis of structure-based fragment docking to elucidate key features for molecular recognition. This hybrid ligand- and structure-based methodology uses an atomic breakdown of the energy terms from the Glide XP scoring function to locate key pharmacophoric features from the docked fragments. First, we show that Glide accurately docks fragments, producing a root mean squared deviation (RMSD) of <1.0 Å for the top scoring pose to the native crystal structure. We then describe fragment-specific docking settings developed to generate poses that explore every pocket of a binding site while maintaining the docking accuracy of the top scoring pose. Next, we describe how the energy terms from the Glide XP scoring function are mapped onto pharmacophore sites from the docked fragments in order to rank their importance for binding. Using this energetic analysis we show that the most energetically favorable pharmacophore sites are consistent with features from known tight binding compounds. Finally, we describe a method to use the energetically selected sites from fragment docking to develop a pharmacophore hypothesis that can be used in virtual database screening to retrieve diverse compounds. We find that this method produces viable hypotheses that are consistent with known active compounds. In addition to retrieving diverse compounds that are not biased by the co-crystallized ligand, the method is able to recover known active compounds from a database screen, with an average enrichment of 8.1 in the top 1% of the database. [ABSTRACT FROM AUTHOR]

The affinity toward the PAC1 receptor, the biological activity, and the α-helical content of several truncated PACAP27 analogs were measured. We first evaluated the pharmacological and structural parameters of C-terminal shortened PACAP fragments, from PACAP(1–23) to PACAP(1–19). All carboxy-truncated derivatives demonstrated circular dichroism spectra typical of a helical conformation. On the other hand, progressive shortening of the C-terminal domain gradually decreases the potency of PACAP to bind and to activate the PAC1 receptor. This decrease in biological activity was mainly attributed to the removal of residues that seem to interact directly with the receptor rather than to a destabilization of the C-terminal helical conformation. We also investigated the pharmacological and conformational characteristics of several hybrid PACAP27 derivatives containing an aliphatic molecular spacer connecting the N-terminal domain to the C-terminal region. However, this strategy revealed that none of these discontinuous analogs showed any significant affinity toward the PAC1 receptor, even if some of them exhibited circular dichroism spectra corresponding to an α-helical structure. This study suggests that several domains of PACAP27 are involved in the interaction with the PAC1 receptor and that the presence of the helical conformation is not a sufficient feature for receptor activation. [ABSTRACT FROM AUTHOR]

We present a component-based framework for face detection and identification. The face detection and identification modules share the same hierarchical architecture. They both consist of two layers of classifiers, a layer with a set of component classifiers and a layer with a single combination classifier. The component classifiers independently detect/identify facial parts in the image. Their outputs are passed the combination classifier which performs the final detection/identification of the face. We describe an algorithm which automatically learns two separate sets of facial components for the detection and identification tasks. In experiments we compare the detection and identification systems to standard global approaches. The experimental results clearly show that our component-based approach is superior to global approaches. [ABSTRACT FROM AUTHOR]

The breakage of a tiny tail on a head of solid glass just removed from a glass bath and treated by fluoric acid (a “Batavian tear") makes the tear explode into a cloud of dust with the sound like that of a shot. This explosion reminds that of TNT but TNT disintegrates into molecules of the order of 10−9 m while the glass particles of dust are of the order of 10−6 m and have the same chemical composition as the solid glass. Rock bursts in deep mines of South Africa and Russia represent another example of the sudden, explosive self-destruction. To explain this phenomenon the theory of self-sustaining fracture waves was suggested earlier by Galin and Cherepanov (1966). This theory was based on the analogy with detonation waves later criticized as insufficiently substantiated. The approach presented below is based only on the conservation laws and does not use any analogies. It proves that the self-sustaining fracture wave can propagate only in compressed structures at the speed of longitudinal elastic waves. [ABSTRACT FROM AUTHOR]