RESUMEN
Owing to their remarkable physical properties, cellular structures, such as triply periodic minimal surfaces (TPMS), have multidisciplinary and multifunctional applications. Although these structures are observed in nature, examples of TPMS with large length scales in living organisms are exceedingly rare. Recently, microstructure reminiscent of the diamond-type TPMS was documented in the skeleton of the modern knobby starfish Protoreaster nodosus. Here we report a similar microlattice in a 385 Myr old crinoid Haplocrinites, which pushes back the origins of this highly ordered microstructure in echinoderms into the Devonian. Despite the low Mg2+/Ca2+ ratio of the 'calcite' Devonian sea, the skeleton of these crinoids has high-Mg content, which indicates strong biological control over biomineralogy. We suggest that such an optimization of trabecular arrangement additionally enriched in magnesium, which enhances the mechanical properties, might have evolved in these crinoids in response to increased predation pressure during the Middle Palaeozoic Marine Revolution. This discovery illustrates the remarkable ability of echinoderms, through the process of evolutionary optimization, to form a lightweight, stiff and damage-tolerant skeleton, which serves as an inspiration for biomimetic materials.
Asunto(s)
Evolución Biológica , Equinodermos , Animales , Equinodermos/fisiología , Estrellas de MarRESUMEN
Fibre optic sensors with integrated Bragg gratings are widely used in the diagnostics of machinery and equipment. They achieved their popularity thanks to their relatively simple operating principles. In addition, they allow the continuous monitoring of several variable physical parameters of objects, such as strain or temperature change, which directly translates into immediate feedback regarding potential damage. However, despite the easy-to-understand operating principle, selecting a specific type for a particular application can be problematic. This article aims to present the process of selecting the optimal set of fibre-optic sensors with integrated Bragg grating, which can be used in the process of monitoring the stress state of hanger rods of an engineering object such as an industrial boiler. The hanger rods of such boilers require constant technical supervision; however, the current measurement methods do not provide an effective and non-invasive diagnostic method. Therefore, the authors have undertaken the task of developing a universal diagnostic strategy for hanger rods. To this end, they will present the results of an analysis of the applicability of FBGs, examples of the use of different types of sensors, their installation methods, and the technical capabilities of the equipment necessary to handle the signals recorded with these sensors. Exemplary results of strain measurements of a selected hanger rod performed by the traditional method used now and with a selected FBG fibre optic sensor will be presented. In conclusion, concrete technical suggestions will be presented to be implemented in the existing industrial facility during the next part of the study.
RESUMEN
Aluminium (Al) is the most ubiquitous metal in the Earth's crust. Even though its toxicity is well-documented, the role of Al in the pathogenesis of several neurological diseases remains debatable. To establish the basic framework for future studies, we review literature reports on Al toxicokinetics and its role in Alzheimer's disease (AD), autism spectrum disorder (ASD), alcohol use disorder (AUD), multiple sclerosis (MS), Parkinson's disease (PD), and dialysis encephalopathy (DE) from 1976 to 2022. Despite poor absorption via mucosa, the biggest amount of Al comes with food, drinking water, and inhalation. Vaccines introduce negligible amounts of Al, while the data on skin absorption (which might be linked with carcinogenesis) is limited and requires further investigation. In the above-mentioned diseases, the literature shows excessive Al accumulation in the central nervous system (AD, AUD, MS, PD, DE) and epidemiological links between greater Al exposition and their increased prevalence (AD, PD, DE). Moreover, the literature suggests that Al has the potential as a marker of disease (AD, PD) and beneficial results of Al chelator use (such as cognitive improvement in AD, AUD, MS, and DE cases).
Asunto(s)
Enfermedad de Alzheimer , Trastorno del Espectro Autista , Esclerosis Múltiple , Enfermedad de Parkinson , Humanos , Aluminio/toxicidad , Trastorno del Espectro Autista/patología , Encéfalo/patología , Enfermedad de Alzheimer/patología , Sistema Nervioso Central/patología , Enfermedad de Parkinson/patología , Esclerosis Múltiple/patologíaRESUMEN
Burrowed discontinuity surfaces associated with condensed fossil concentrations demarcate breaks (hiatuses) in the Phanerozoic marine sedimentary record. Such intervals may be difficult to interpret in view of complex anatomy and varied fossil signatures. Transformation of a discontinuity surface into a heavily burrowed 'pseudobreccia' may further complicate the record, but this issue has remained unexploited to date. The richly fossiliferous Cretaceous-Paleogene (Maastrichtian-Danian) boundary interval exposed in Poland provides opportunities to test the influence of burrow-generated pseudobreccia on the preservation of associated hiatal fossil concentrations. Here, we document pseudobreccia anatomy and fossil-sediment relationships by three-dimensional X-ray computed tomography imaging. In the pseudobreccia zone, we identify a distinctive assemblage of late Maastrichtian fossils, which underwent subsurface preparation by burrowers in a hitherto unreported ichno-taphonomic process. Recognition of pseudobreccia is a prerequisite for the interpretation of the stratigraphy, sedimentology and fossil record of such intervals, which is of special interest for periods of major biotic turnovers, like the end-Cretaceous mass extinction.
RESUMEN
While the occurrence of skeletal pathologies in Middle Triassic marine reptiles has been poorly documented until now, massive accumulations of bone remains from the Germanic Basin provide the opportunities for documentation. Herein, we describe skeletal abnormalities in the Middle Triassic bone material from the Vossenveld Formation of Winterswijk, the Netherlands. The aim of the study is to distinguish in the studied bones pathologies resulting from malady or trauma and taphonomic alterations. Furthermore, an attempt was made to assess on how the pathologies also represent paleoecological data. Our survey led to the identification of one broken and healed bone, one case of abnormal coossification, and one case of posttraumatic fibro-osseous dysplasia. While the latter two pathologies give little insight into the ecology and function of the affected animals, the fractured dentary is attributed to Nothosaurus marchicus, a common sauropterygian macropredator. It proves that the individual survived long enough to heal, despite the injury hampering its hunting potential. One abnormally shaped humerus is interpreted as postmortem taphonomic deformation, emphasizing the necessity of utilization of detailed diagnostics to distinguish actual paleopathologies from nonbiological distortion.
Asunto(s)
Fósiles , Reptiles , Animales , Reptiles/anatomía & histología , HúmeroRESUMEN
Aim: The study aimed to analyze the weight and homogeneity of the parts of tablets containing carbamazepine and tablets with trazodone hydrochloride, obtained after subdivision with a kitchen knife. X-ray microtomography was used for homogeneity analysis. Methods: 30 tablets with carbamazepine and 30 tablets with trazodone hydrochloride were analyzed in terms of weight uniformity after subdivision. Then, seven tablets of each type were analyzed using an X-ray microtomography (Phoenix vÇtomeÇx, General Electric). The absorption of X-rays by an object is proportional to its density. In turn, measurement of the density of the analyzed object in a microtomographic image is the grayscale level. Based on the correlation between the grayscale value and the reference density, from the calibration phantom, we were able to determine the density of any area of the tablet's scan. Results: During the subdivision, the weight loss exceeded 3% for two carbamazepine tablets, while for trazodone tablets, none lost more than 3%, which is the limit recommended by Food and Drug Administration (FDA). As to the density of the tablets resulting from the microtomographic analysis, two of the whole tablets containing trazodone hydrochloride had a significantly higher density than the remainder (p < 0.001). Similarly, some differences in density were observed in the analysis of the density of tablets of carbamazepine (p = 0.008). Parts of one of the analyzed tablets with trazodone obtained after subdivision differed in terms of pixel brightness, thus density. On the other hand, the uniform density was observed for parts of the split tablets containing carbamazepine. Conclusions: Parts of the trazodone hydrochloride tablets obtained after subdivision differed in terms of homogeneity and weight. Microtomographic methods may be an interesting and useful method for evaluating the uniformity of compounds in solid dosage forms.
RESUMEN
Epilepsy is an important medical problem with approximately 50 million patients globally. No more than 70% of epileptic patients will achieve seizure control after antiepileptic drugs, and several epileptic syndromes, including Lennox-Gastaut syndrome (LGS), are predisposed to more frequent pharmacoresistance. Ketogenic dietary therapies (KDTs) are a form of non-pharmacological treatments used in attempts to provide seizure control for LGS patients who experience pharmacoresistance. Our review aimed to evaluate the efficacy and practicalities concerning the use of KDTs in LGS. In general, KDTs are diets rich in fat and low in carbohydrates that put the organism into the state of ketosis. A classic ketogenic diet (cKD) is the best-evaluated KDT, while alternative KDTs, such as the medium-chain triglyceride diet (MCT), modified Atkins diet (MAD), and low glycemic index treatment (LGIT) present several advantages due to their better tolerability and easier administration. The literature reports regarding LGS suggest that KDTs can provide ≥50% seizure reduction and seizure-free status in a considerable percentage of the patients. The most commonly reported adverse effects are constipation, diarrhea, and vomiting, while severe adverse effects such as nephrolithiasis or osteopenia are rarely reported. The literature review suggests that KDTs can be applied safely and are effective in LGS treatment.
Asunto(s)
Dieta Cetogénica , Epilepsia , Síndrome de Lennox-Gastaut , Humanos , Síndrome de Lennox-Gastaut/tratamiento farmacológico , Dieta Cetogénica/efectos adversos , Estudios Retrospectivos , Convulsiones , Anticonvulsivantes/uso terapéutico , Resultado del TratamientoRESUMEN
Fossil comatulids, referred to as feather stars, are mostly known from highly disarticulated specimens. A single isolated element (centrodorsal) has been the basis for taxonomic description of a vast majority of fossil comatulids. Here, we report a nearly complete, and thus extremely rare, comatulid from the Upper Jurassic (Tithonian) of the Blue Nile Basin in central western Ethiopia that provides a unique insight into the morphology of comatulid arms and cirri. It is assigned to Ausichicrinites zelenskyyi gen. et sp. nov. and is the first Jurassic comatulid from the African continent. The new taxon shows some similarities with representatives of the Mesozoic Solanocrinitidae but also has close resemblance with the modern family Zygometridae, exclusively known from the Holocene of western Pacific and eastern Indian Oceans. This morphologic similarity is considered to be due to convergence. The first example of pinnule regeneration in a fossil feather star is reported, which reinforces the hypothesis about the importance of predation in the evolution of these crinoids.
RESUMEN
Excrement-shaped ferruginous masses have been recovered from the Miocene of Turów mine in south-western Poland. These siderite masses have been the subject of much controversy, having been interpreted either as being coprolites, cololithes or pseudofossils created by mechanical deformation of plastic sediment. Here we present the results of mineralogical, geochemical, petrographic and microtomographical analyses. Our data indicate that these masses consist of siderite and iron oxide rather than phosphate, and rarely contain recognizable food residues, which may suggest abiotic origins of these structures. On the other hand, evidence in support of a fecal origin include: (i) the presence of two distinct morphotypes differing in size and shape, (ii) the presence of rare hair-like structures or coalified inclusions and (iii) the presence of rare fine striations on the surface. Importantly, comparative actualistic study of recent vertebrate feces shows overall resemblance of the first morphotype (sausage-shaped with rare coalified debris) to excrements of testudinoid turtles (Testudinoidea), whose shell fragment was found in the investigated locality. The second morphotype (rounded to oval-shaped with hair-like structures), in turn, is similar to the feces of some snakes (Serpentes), the remains of which were noted in the Miocene of the neighborhood areas. Other potential producers (such as lizards and crocodiles) and even abiotic origins cannot be fully excluded but are less likely.
Asunto(s)
Fósiles , Lagartos , Animales , Polonia , Lagartos/anatomía & histología , SerpientesRESUMEN
Hepatocellular carcinoma (HCC) is the most common primary liver cancer with an increasing worldwide mortality rate. Cholangiocarcinoma (CCA) is the second most common primary liver cancer. In both types of cancers, early detection is very important. Biomarkers are a relevant part of diagnosis, enabling non-invasive detection and control of cancer recurrence, as well as in the application of screening tests in high-risk groups. Furthermore, some of these biomarkers are useful in controlling therapy and treatment selection. Detection of some markers presents higher sensitivity and specificity in combination with other markers when compared with a single detection. Some gene aberrations are also prognostic markers in the two types of cancers. In the following review, we discuss the most common biomarkers and genetic markers currently being used in the diagnosis of hepatocellular carcinoma and cholangiocarcinoma.
RESUMEN
BACKGROUND: Neoplasms are common across the animal kingdom and seem to be a feature plesiomorphic for metazoans, related with an increase in somatic complexity. The fossil record of cancer complements our knowledge of the origin of neoplasms and vulnerability of various vertebrate taxa. Here, we document the first undoubted record of primary malignant bone tumour in a Mesozoic non-amniote. The diagnosed osteosarcoma developed in the vertebral intercentrum of a temnospondyl amphibian, Metoposaurus krasiejowensis from the Krasiejów locality, southern Poland. RESULTS: A wide array of data collected from gross anatomy, histology, and microstructure of the affected intercentrum reveals the tumour growth dynamics and pathophysiological aspects of the neoplasm formation on the histological level. The pathological process almost exclusively pertains to the periosteal part of the bone composed from a highly vascularised tissue with lamellar matrix. The unorganised arrangement of osteocyte lacunae observed in the tissue is characteristic for bone tissue types connected with static osteogenesis, and not for lamellar bone. The neoplastic bone mimics on the structural level the fast growing fibrolamellar bone, but on the histological level develops through a novel ossification type. The physiological process of bone remodelling inside the endochondral domain continued uninterrupted across the pathology of the periosteal part. CONCLUSIONS: Based on the results, we discuss our case study's consistence with the Tissue Organization Field Theory of tumorigenesis, which locates the causes of neoplastic transformations in disorders of tissue architecture.
Asunto(s)
Neoplasias , Osteogénesis , Animales , Osteogénesis/fisiología , Fósiles , Huesos , CarcinogénesisRESUMEN
The main aim of this study was to analyze microtomographic data to determine the geometric dimensions of a ceramic porous material's internal structure. Samples of a porous corundum biomaterial were the research material. The samples were prepared by chemical foaming and were measured using an X-ray scanner. In the next stage, 3D images of the samples were generated and analyzed using Thermo Scientific Avizo software. The analysis enabled the isolation of individual pores. Then, the parameters characterizing the pore geometry and the porosity of the samples were calculated. The last part of the research consisted of verifying the developed method by comparing the obtained results with the parameters obtained from the microscopic examinations of the biomaterial. The comparison of the results confirmed the correctness of the developed method. The developed methodology can be used to analyze biomaterial samples to assess the geometric dimensions of biomaterial pores.
RESUMEN
In view of the aging population and various diseases worldwide, the demand for implants has been rapidly increasing. Despite the efforts of doctors, engineers, and medical companies, the fabrication of and procedures associated with implants have not yet been perfected. Therefore, a high percentage of premature implantations has been observed. The main problem with metal implants is the mechanical mismatch between human bone and the implant material. Zirconium/titanium-based materials with graded porosity and composition were prepared by powder metallurgy. The whole samples are comprised of three zones, with a radial gradient in the phase composition, microstructure, and pore structure. The samples were prepared by a three-step powder metallurgy method. The microstructure and properties were observed to change gradually with the distance from the center of the sample. The x-ray diffraction analysis and microstructure observation confirmed the formation of diffusive connections between the particular areas. Additionally, the mechanical properties of the obtained materials were checked, with respect to the distance from the center of the sample. An analysis of the corrosion properties of the obtained materials was also carried out.
RESUMEN
The coexistence of sessile, tube-dwelling polychaetes (serpulids) and hydroids, has been investigated. Serpulid tubes bearing traces after hydroids are derived from different stratigraphic intervals spanning the Middle and Upper Jurassic, the rocks of which represent the diverse paleoenvironments of the Polish Basin. Although fossil colonial hydroids classified under the species Protulophila gestroi are a commonly occurring symbiont of these polychaetes during the Late Cretaceous and Cenozoic, they seem to be significantly less frequent during the Jurassic and limited to specific paleoenvironments. The hydroids described here are represented by traces after a thin stolonal network with elongated polyp chambers that open to the outer polychaete tube's surface with small, more or less subcircular apertures. Small chimney-like bulges around openings are an effect of the incorporation of the organism by in vivo embedment (bioclaustration) within the outer layers of the calcareous tube of the serpulid host. Considering the rich collection of well-preserved serpulid tubes (>3000 specimens), the frequency of bioclaustrated hydroids is very low, with an infestation percentage of only 0.6% (20 cases). It has been noticed that only specimens of the genus Propomatoceros from the Upper Bajocian, Lower Bathonian, Middle Bathonian, and Callovian have been found infested. However, the majority of bioclaustrated hydroids (17 cases) have been recorded in the Middle Bathonian serpulid species Propomatoceros lumbricalis coming from a single sampled site. Representatives of other genera are not affected, which is congruent with previous reports indicating that Protulophila gestroi was strongly selective in the choice of its host. A presumably commensal relationship is compared with the recent symbiosis between the hydroids of the genus Proboscidactyla and certain genera of sabellid polychaetes.
Asunto(s)
Fósiles , Hidrozoos/fisiología , Poliquetos/fisiología , Animales , Polonia , SimbiosisRESUMEN
Current zoological research may benefit in many ways from the study of old collections of shells. These collections may provide materials for the verification of broad zoogeographical and ecological hypotheses on the reproduction of molluscs, as they include records from many areas where sampling is currently impossible or very difficult due to political circumstances. In the present paper we present data on viviparous and embryo-retention reproductive modes in clausiliid land snails (subfamily Phaedusinae) acquired from specimens collected since the nineteenth century in the Pontic, Hyrcanian, and East and Southeast Asian regions. X-ray imaging (micro-CT) enabled relatively quick screening of more than 1,000 individuals classified within 141 taxa, among which we discovered 205 shells containing embryos or eggs. Gravid individuals were found to belong to 55 species, representing, for some of these species, the first indication of brooding reproductive strategy.
Asunto(s)
Exoesqueleto/fisiología , Caracoles/clasificación , Microtomografía por Rayos X , Exoesqueleto/diagnóstico por imagen , Animales , Biodiversidad , Evolución Biológica , Huevos/análisis , Huevos/historia , Embrión no Mamífero/diagnóstico por imagen , Embrión no Mamífero/fisiología , Historia del Siglo XIX , Caracoles/crecimiento & desarrolloRESUMEN
In this paper, we propose a recursive variant of the Parzen kernel density estimator (KDE) to track changes of dynamic density over data streams in a nonstationary environment. In stationary environments, well-established traditional KDE techniques have nice asymptotic properties. Their existing extensions to deal with stream data are mostly based on various heuristic concepts (losing convergence properties). In this paper, we study recursive KDEs, called recursive concept drift tracking KDEs, and prove their weak (in probability) and strong (with probability one) convergence, resulting in perfect tracking properties as the sample size approaches infinity. In three theorems and subsequent examples, we show how to choose the bandwidth and learning rate of a recursive KDE in order to ensure weak and strong convergence. The simulation results illustrate the effectiveness of our algorithm both for density estimation and classification over time-varying stream data.
RESUMEN
The practice of drug counterfeiting is an important challenge due to the extremely rapid growth rate of this disturbing trend and its immense potential harmfulness. According to WHO even 10% of counterfeit medicines can be exact copies of genuine medicines: they have exactly the same quantitative and qualitative composition in terms of both API and excipients. Thus, the identification of such drugs using chemical analysis methods can be very difficult or even impossible. The aim of this study was to verify the effectiveness of using computed microtomography in the identification of counterfeit medicines. The General Electric v|tome|x s microtomography system was used in the study. The recorded microtomographic scans were subjected to analysis and image processing. The following parameters of image analysis and processing were identified: mean brightness, homogeneity, contrast, quadratic tree decomposition. The original and falsified 100-mg Viagra® tablets (Pfizer) were compared. 8 original Viagra® tablets (hereinafter referred to as T) and 8 falsified tablets (hereinafter referred to as F1-F8) were tested. The range of variation for the genuine medicines against fake products was: brightness: 90.9-117.1 vs 33.8, 50.1, homogeneity: 0.84-0.92 vs 0.94-1.01 and quadratic tree decomposition for the 1â¯×â¯1 mask: 55768-58792 vs 0-439. The proposed method of microtomographic image analysis and processing enables to identify solid dosage forms, including those that are an accurate chemical copy, with high sensitivity and specificity, 94.5% and 97%, respectively. The advantage of the µCT method is its high efficiency and speed, whereas the disadvantages include the possibility of using only solid dosage forms and high equipment costs.
Asunto(s)
Medicamentos Falsificados/análisis , Inhibidores de Fosfodiesterasa 5/análisis , Citrato de Sildenafil/análisis , Microtomografía por Rayos XRESUMEN
The most popular tools for stream data mining are based on decision trees. In previous 15 years, all designed methods, headed by the very fast decision tree algorithm, relayed on Hoeffding's inequality and hundreds of researchers followed this scheme. Recently, we have demonstrated that although the Hoeffding decision trees are an effective tool for dealing with stream data, they are a purely heuristic procedure; for example, classical decision trees such as ID3 or CART cannot be adopted to data stream mining using Hoeffding's inequality. Therefore, there is an urgent need to develop new algorithms, which are both mathematically justified and characterized by good performance. In this paper, we address this problem by developing a family of new splitting criteria for classification in stationary data streams and investigating their probabilistic properties. The new criteria, derived using appropriate statistical tools, are based on the misclassification error and the Gini index impurity measures. The general division of splitting criteria into two types is proposed. Attributes chosen based on type- splitting criteria guarantee, with high probability, the highest expected value of split measure. Type- criteria ensure that the chosen attribute is the same, with high probability, as it would be chosen based on the whole infinite data stream. Moreover, in this paper, two hybrid splitting criteria are proposed, which are the combinations of single criteria based on the misclassification error and Gini index.
RESUMEN
One of the greatest challenges in data mining is related to processing and analysis of massive data streams. Contrary to traditional static data mining problems, data streams require that each element is processed only once, the amount of allocated memory is constant and the models incorporate changes of investigated streams. A vast majority of available methods have been developed for data stream classification and only a few of them attempted to solve regression problems, using various heuristic approaches. In this paper, we develop mathematically justified regression models working in a time-varying environment. More specifically, we study incremental versions of generalized regression neural networks, called IGRNNs, and we prove their tracking properties - weak (in probability) and strong (with probability one) convergence assuming various concept drift scenarios. First, we present the IGRNNs, based on the Parzen kernels, for modeling stationary systems under nonstationary noise. Next, we extend our approach to modeling time-varying systems under nonstationary noise. We present several types of concept drifts to be handled by our approach in such a way that weak and strong convergence holds under certain conditions. Finally, in the series of simulations, we compare our method with commonly used heuristic approaches, based on forgetting mechanism or sliding windows, to deal with concept drift. Finally, we apply our concept in a real life scenario solving the problem of currency exchange rates prediction.
Asunto(s)
Algoritmos , Minería de Datos , Aprendizaje , Modelos Neurológicos , Redes Neurales de la Computación , Análisis de Regresión , Simulación por Computador , Humanos , Factores de TiempoRESUMEN
The uniformity of dosage units within a certain batch is ensured when each unit contains the active pharmaceutical ingredient (API) within a narrow range around the label claim. For tablets containing a score-line authorised for dose reductions, the European Pharmacopoeia (Ph. Eur.) considers that the uniformity of the tablet parts may be based on weight measurements regardless of the tablet type (immediate or modified release). This is because it is up to the regulatory authorities first to assess whether the tablet may contain a score-line for such use. X-ray microtomography was applied to assess the symmetry of 36 modified release tablets, containing 300mg of theophylline. The sum of the volume and surface area of the pellets in the subdivided tablets were compared. Simulations were carried out to identify the optimal amount of pellets in the tablet mass. The maximum difference in the API content between two subdivided halves was 165.18mg vs 133.83mg. If the amount of pellets in the tablet mass would drop below 13% on the basis of the pellet surface area, then the Ph. Eur. requirements would be exceeded. The amount of pellets in the tablet halves resulting in the greatest variability in API content was 38%. The results of this study indicate that the pellets were not distributed uniformly in the tablet mass. Thus, the uniformity of the dose in both halves of a tablet containing pellets cannot be based on the weight measurements i.e. it is necessary to develop further standards for tablet subdivision. Microtomographic methods are a very interesting alternative to expensive and time-consuming pharmacokinetic studies.