293 research outputs found
Charcoal-containing building materials for electromagnetic radiation shielding
he aim of the study presented in the current article was to experimentally substantiate the possibility of obtaining the cost effective building materials for electromagnetic radiation shielding by using powdered charcoal as a filler. Such charcoal properties as low cost and high carbon content (up to 90.0 wt.%) were the prerequisites for the study. To achieve the goal, a method for obtaining composite materials based on powdered charcoal and building gypsum was developed and experimentally substantiated by the authors. Further, the samples of charcoal-containing building materials were made according to the developed method and the electromagnetic radiation reflection and transmission coefficients values of the samples were measured in the frequency range of 0.7–17.0 GHz using scalar network analyzer. According to the measurements results, it was found that the average value of the electromagnetic radiation reflection coefficient in the specified frequency range of the materials produced in accordance with the presented method (when these materials thickness was equal to 1.0 cm) was –3.0 dB, and the average value of the electromagnetic radiation transmission coefficient was –25.0 dB. The studied materials are recommended for use in electromagnetic shielding of the rooms housing the electronic devices
Numerical simulation of synthesis gas incineration
The authors have analysed the expediency of the suggested low-grade fuels application method. Thermal processing of solid raw materials in the gaseous fuel, called synthesis gas, is investigated. The technical challenges concerning the applicability of the existing gas equipment developed and extensively tested exclusively for natural gas were considered. For this purpose computer simulation of three-dimensional syngas-incinerating flame dynamics was performed by means of the ANSYS Multiphysics engineering software. The subjects of studying were: a three-dimensional aerodynamic flame structure, heat-release and temperature fields, a set of combustion properties: a flare range and the concentration distribution of burnout reagents. The obtained results were presented in the form of a time-averaged pathlines with color indexing. The obtained results can be used for qualitative and quantitative evaluation of complex multicomponent gas incineration singularities
Dependence of the diffusion wear of the hard alloy surface on its fractal dimension
The paper presents the research results in the synergies between the wear resistance of carbide cutting tools of P-group applicability and fractal dimension of the wear surface occurring on the rake face of the tool when processing the material, which causes intensive diffusion wear. It was found that the resistance of carbide cutting tools increases as the fractal dimension of their wear surface reduces
Features of empathy among students of the direction "Ecology and nature management" with different mathematical abilities and strategies for conveying meaning
Today, the entire education of the Russian Federation is being reformed, high requirements for the quality of education have been set. The restructuring and integration of the world educational process expects high efficiency of all educational activities, therefore, the problem of the study of mathematical abilities and the ability to convey meaning of students is particularly relevant today. Equally important is the problem of educating socially approved personality traits in the younger generation, including empathy. The study allowed us to establish that students with an average level of development of mathematical abilities have significantly less formed empathy, and vice versa, with the development of communicative properties, there is an increase in empathy abilities. It has been established that empathy is best formed in students of the direction "Ecology and nature management" with an active, emotionally dominant and cognitively dominant strategy for conveying meaning
Closed-system behaviour of the Re-Os isotope system recorded in primary and secondary platinum-group mineral assemblages : evidence from a mantle chromitite at Harold's Grave (Shetland ophiolite complex, Scotland)
This study evaluates in detail the mineral chemistry, wholerock and mineral separate Os-isotope compositions of distinct platinumgroup mineral (PGM) assemblages in an isolated chromitite pod at Harold's Grave which occurs in mantle tectonite in the Shetland Ophiolite Complex (SOC), Scotland. This was the first ophiolite sequence worldwide that was shown to contain ppm levels of all six platinum-group elements (PGE) in podiform chromitite, including the contrasting type localities found here and at Cliff. At Harold's Grave the primary PGM assemblage is composed mainly of laurite and/or Os-rich iridium and formed early together with chromite, whereas the secondary PGM assemblage dominated by laurite, Osrich laurite, irarsite, native osmium and Ru-bearing pentlandite is likely to reflect processes including in-situ serpentinization, alteration during emplacement and regional greenschist metamorphism. The osmium isotope data define a restricted range of 'unradiogenic' 187Os/188Os values for coexisting laurite and Os-rich alloy pairs from 'primary' PGM assemblage (0.12473-0.12488) and similar 'unradiogenic' 187Os/188Os values for both 'primary' and 'secondary' PGM assemblages (0.1242±0.0008 and 0.1245±0.0006, respectively), which closely match the bulk 187Os/188Os value of their host chromitite (0.1240±0.0006). The unprecedented isotopic similarity between primary or secondary PGM assemblages and chromitite we report suggests that the osmium isotope budget of chromitite is largely controlled by the contained laurite and Os-rich alloy. This demonstrates that closed system behaviour of the Re- Os isotope system is possible, even during complex postmagmatic hydrothermal and/or metamorphic events. The preserved mantle Os-isotope signatures provide further support for an Enstatite Chondrite Reservoir (ECR) model for the convective upper mantle and are consistent with origin of the complex as a Caledonian ophiolite formed in a suprasubduction zone setting shortly before obduction
Zircon U-Pb and Hf isotopic constraints on the genesis of a post-kinematic S-type Variscan tin granite: the Logrosán cupola (Central Iberian Zone)
The Variscan orogeny produced widespread granites along the European Variscan belt. In relation to crustal thickening, post-collisional multiple tin-bearing highly fractionated S-type leucogranites were emplaced. The Logrosán granite represents one of those granitic bodies and is a focus of this study. The Logrosán granite is located in the Central Extremadura Batholith (CEB), within the Central Iberian Zone (CIZ) and was emplaced during post kinematic stages of the Variscan orogeny at ca. 308 Ma, as determined by combined ID-TIMS U–Pb and LA-ICPMS geochronology. The granitic body intruded the metasedimentary Schist Greywacke Complex (SGC) of Neoproterozoic age. A moderately evolved medium- to coarse-grained two mica leucogranite (Main unit) and some highly evolved aplitic or microporphyritic units (evolved units) are distinguishable on the basis of their petrography and whole rock geochemistry. Initial 87Sr/86Sr ratios vary from 0.7134 to 0.7311, whereas initial εNd shows a restricted range from -4.3 to -4.0 and εHf(t) ranges from +2.0 to -4.6 for Variscan-age zircons. Inherited zircons exhibit mostly Neoproterozoic ages and juvenile Hf-isotope composition (eHf up to +14.6), analogous to that of zircons from the SGC metasediments. The available geological, geochronological, geochemical and isotopic data allow to propose the partial melting of heterogeneous Neoproterozoic metasedimentary material, similar to the outcropping SGC, for the genesis of the Logrosán granite.La orogenia Varisca produjo una gran cantidad de granitos a lo largo del Cinturón Varisco Europeo. En relación con el engrosamiento cortical se emplazaron tardíamente granitos de tipo-S, muy fraccionados y ricos en Sn. El presente estudio se centra en uno de esos cuerpos graníticos, el granito de Logrosán. El plutón de Logrosán forma parte del Batolito de Extremadura Central (BEC), en la Zona Centroibérica (ZCI), y se emplazó durante las etapas tardías de la orogenia Varisca, a los ca. 308 Ma, según los datos combinados de geocronología de U-Pb por ID-TIMS y por LA-ICPMS. El cuerpo granítico intruyó los metasedimentos del Complejo Esquisto Grauváquico (CEG) de edad fundamentalmente Neoproterozoica. En el plutón se distinguen, de acuerdo a la petrografía y a la geoquímica de roca total, un leucogranito de dos micas de tamaño de grano medio-grueso moderadamente evolucionado (Main Unit) y varias unidades aplíticas o microporfídicas altamente evolucionadas (Evolved Units). Las relaciones isotópicas iniciales de 87Sr/86Sr varían de 0.7125 a 0.7286, mientras que el εNd inicial muestra un rango restringido de -4.3 a -4.0 y el εHf(t) en circones variscos oscila de +5.7 a -10.5. Los circones heredados del granito de Logrosán muestran edades principalmente Neoproterozoicas y composiciones isotópicas de Hf juveniles (εHf > +14.7), análogas a las encontradas en los circones del CEG. Los datos geológicos, geoquímicos, geocronológicos e isotópicos de los que se dispone sugieren que el granito de Logrosán se originó por la fusión parcial de materiales metasedimentarios Neoproterozoicos similares a los del CEG
The discovery of kimberlites in antarctica extends the vast gondwanan cretaceous province
Kimberlites are a volumetrically minor component of the Earth's volcanic record, but are very important as the major commercial source of diamonds and as the deepest samples of the Earth's mantle. They were predominantly emplaced from ≈2,100 Ma to ≈1
Historical Patterns of Diagnosis, Treatments, and Outcome of Epilepsy Associated With Tuberous Sclerosis Complex: Results From TOSCA Registry
TOSCA; Epilepsia; RegistroTOSCA; Epilèpsia; RegistreTOSCA; Epilepsy; RegistryBackground: Epilepsy is the most common neurological manifestation in individuals with tuberous sclerosis complex (TSC). However, real-world evidence on diagnosis and treatment patterns is limited. Here, we present data from TuberOus Sclerosis registry to increase disease Awareness (TOSCA) on changes in patterns of epilepsy diagnosis, treatments, and outcomes over time, and detailed epilepsy characteristics from the epilepsy substudy.
Methods: TuberOus Sclerosis registry to increase disease Awareness (TOSCA) was a multicentre, international disease registry, consisting of a main study that collected data on overall diagnostic characteristics and associated clinical features, and six substudies focusing on specific TSC manifestations. The epilepsy substudy investigated detailed epilepsy characteristics and their correlation to genotype and intelligence quotient (IQ).
Results: Epilepsy was reported in 85% of participants, more commonly in younger individuals (67.8% in 1970s to 91.8% in last decade), while rate of treatments was similar across ages (>93% for both infantile spasms and focal seizures, except prior to 1960). Vigabatrin (VGB) was the most commonly used antiepileptic drugs (AEDs). Individuals with infantile spasms showed a higher treatment response over time with lower usage of steroids. Individuals with focal seizures reported similar rates of drug resistance (32.5–43.3%). Use of vagus nerve stimulation (VNS), ketogenic diet, and surgery remained low.
Discussion: The epilepsy substudy included 162 individuals from nine countries. At epilepsy onset, most individuals with infantile spasms (73.2%) and focal seizures (74.5%) received monotherapies. Vigabatrin was first-line treatment in 45% of individuals with infantile spasms. Changes in initial AEDs were commonly reported due to inadequate efficacy. TSC1 mutations were associated with less severe epilepsy phenotypes and more individuals with normal IQ. In individuals with TSC diagnosis before seizure onset, electroencephalogram (EEG) was performed prior to seizures in only 12.5 and 25% of subsequent infantile spasms and focal seizures, respectively.
Conclusions: Our study confirms the high prevalence of epilepsy in TSC individuals and less severe phenotypes with TSC1 mutations. Vigabatrin improved the outcome of infantile spasms and should be used as first-line treatment. There is, however, still a need for improving therapies in focal seizures. Electroencephalogram follow-up prior to seizure-onset should be promoted for all infants with TSC in order to facilitate preventive or early treatment.The study was funded by Novartis Pharma AG. Novartis has contributed to study design, data analysis and the decision to publish. Novartis authors reviewed the draft for submission
Rare manifestations and malignancies in tuberous sclerosis complex: findings from the TuberOus SClerosis registry to increAse disease awareness (TOSCA)
Manifestación rara; Tosca; Complejo de esclerosis tuberosaManifestació rara; Tosca; Complex d'esclerosi tuberosaRare manifestation; Tosca; Tuberous sclerosis complexBackground
Tuberous sclerosis complex (TSC) is a rare multisystem autosomal dominant disorder caused by pathogenic variants in either the TSC1 or TSC2 gene. Common manifestations of TSC have been grouped into major and minor clinical diagnostic criteria and assessed in clinical routine workup. However, case studies point towards the existence of rare disease manifestations and to the potential association of TSC with malignant tumors. In this study we sought to characterize rare manifestations and malignancies using a large cohort of patients.
Methods
TuberOus SClerosis registry to increAse disease awareness (TOSCA) is a multicenter, international disease registry collecting clinical manifestations and characteristics of patients with TSC, both retrospectively and prospectively. We report rates and characteristics of rare manifestations and malignancies in patients with TSC who had enrolled in the TOSCA registry. We also examined these manifestations by age, sex, and genotype (TSC1 or TSC2).
Results
Overall, 2211 patients with TSC were enrolled in the study. Rare manifestations were reported in 382 (17.3%) study participants and malignancies in 65 (2.9%). Of these rare manifestations, the most frequent were bone sclerotic foci (39.5%), scoliosis (23%), thyroid adenoma (5.5%), adrenal angiomyolipoma (4.5%), hemihypertrophy and pancreatic neuroendocrine tumors (pNET; both 3.1%). These rare manifestations were more commonly observed in adults than children (66.2% vs. 22.7%), in females versus males (58.4% vs. 41.6%; except for scoliosis: 48.9% vs. 51.1%), and in those with TSC2 versus TSC1 (67.0% vs. 21.1%; except for thyroid adenoma: 42.9% vs. 57.1%). In the 65 individuals with reported malignancies, the most common were renal cell carcinoma (47.7%), followed by breast (10.8%) and thyroid cancer (9.2%). Although malignancies were more common in adult patients, 26.1% were reported in children and 63.1% in individuals < 40 years. TSC1 mutations were over-represented in individuals with malignancies compared to the overall TOSCA cohort (32.1% vs. 18.5%).
Conclusion
Rare manifestations were observed in a significant proportion of individuals with TSC. We recommend further examination of rare manifestations in TSC. Collectively, malignancies were infrequent findings in our cohort. However, compared to the general population, malignant tumors occurred earlier in age and some tumor types were more common.The study was funded by Novartis Pharma AG. Novartis has contributed to the study design, data analysis, and the decision to publish. Novartis authors reviewed the draft for submission
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