105 research outputs found

    Cerebellar anaplastic astrocytoma in adult patients: 15 consecutive cases from a single institution and literature review

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    Adult cerebellar anaplastic astrocytomas (cAA) are rare entities and their clinical and genetic appearances are still ill defined. Previously, malignant gliomas of the cerebellum were combined and reviewed together (cAA and cerebellar glioblastomas (cGB), that could have possibly affected overall survival (OS) and progression-free survival (PFS). We present characteristics of 15 adult patients with cAA and compared them to a series of 45 patients with a supratentorial AA (sAA) in order to elicit the effect of tumor location on OS and PFS. The mean age at cAA diagnosis was 39.3 years (range 19–72). A history of neurofibromatosis type I was noted in 1 patient (6.7%). An IDH-1 mutation was identified in 6/15 cases and a methylated MGMT promoter in 5/15 cases. Patients in study and control groups were matched in age, sex and IDH-1 mutation status. Patients in a study group tended to present with longer overall survival (50 vs. 36.5 months), but the difference did not reach statistical significance. In both cAA and supratentorial AA groups presence of the IDH-1 mutation remains a positive predictor for the prolonged survival. The present study suggests that adult cAA constitute a group of gliomas with relatively higher rate of IDH-1 mutations and prognosis similar to supratentorial AA. The present study is the first to systematically compare cAA and supratentorial AA with respect to their genetic characteristics and suggests that both groups show a similar survival prognosis

    Effect of plant communities on aggregate composition and organic matter stabilisation in young soils

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    © 2014, Springer International Publishing Switzerland. Results: Deciduous forest soil accumulated the highest C content in the 0–5 cm layer (43 g C kg−1), whereas values in coniferous forest and arable soils were lower (30 and 12 g C kg−1, respectively). The highest portion of C in arable soil was accumulated in the mineral fraction (80 %), whereas 50–60 % of the C in forest soils were in POM. More C was associated with minerals in deciduous forest soil (16 g C kg−1 soil) than under coniferous forest and arable land (8–10 g C kg−1 soil). Conclusions: Particulate organic matter explains most of the differences in organic C accumulation in soils developed during 45 years under the three vegetation types on identical parent material. The C content of the mineral soil fraction was controlled by plant cover and contributed the most to differences in C accumulation in soils developed under similar vegetation type (forest). Objectives: Carbon (C) content in pools of very young soils that developed during 45 years from loess was analysed in relation to vegetation: deciduous and coniferous forests and cropland. We hypothesised that variations in the amount of particulate organic matter (POM) can explain the C accumulation and also affects the C bound to mineral surfaces in soil under various vegetation. Methods: Soil samples were collected under three vegetation types of a 45-year-old experiment focused on initial soil development. Aggregate and density fractionations were combined to analyse C accumulation in large and small macro- and microaggregates as well as in free and occluded POM and mineral factions

    The results of orthodontic treatment using computer design of structures

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    The article deals with the use of mathematical background and computer modeling in the process of treatment dental apparatus engineering. Drawing on mathematical calculations, veracity of which is validated by the results of experimental research, there in the clinic it has been used treatment appliance made of elastic polymer with set-up parameter

    Efficiency of antinocyceptive support of patients with endodontic interventions for acute periodontitis

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    It is known that periodontitis is an inflammatory disease ofthe connective tissue anatomical formation located in the space between the compact plate of the dental alveoli and the cement of the tooth root. It has been proven that endodontic treatment for complicated forms of carious lesions is based on invasive interventio

    On the elastic constants of the zeolite chlorosodalite

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    The use of force-field based molecular modeling to predict the elastic constants of the zeolite chlorosodalite is described. Theoretical predictions of the on-axis and off-axis elastic constants strongly suggest that an error exists in the published elastic constants of the material. When the previous experimental data are corrected by transposing the published directional ultrasound velocities, excellent agreement is observed between the off-axis plots of sodalite produced by experiment and modeling. Further confirmation of the prediction is supplied by considering the Zener ratios of other inorganic materials that possess cubic symmetry. ©2006 American Institute of Physics

    Comparative evaluation of the effectiveness of methods of alveolar bone preservation before dental implantation

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    This article presents comparative results of the developed concept with the use of a direct immediate prosthetics and a group where the postoperative period was managed without it. The concept of bone preservation before implantation allows not only to preserve the volume of its own tissues, but also prevents the development of complications characteristic of traditional methods of bone augmentatio

    Active medulloblastoma enhancers reveal subgroup-specific cellular origins

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    Medulloblastoma is a highly malignant paediatric brain tumour, often inflicting devastating consequences on the developing child. Genomic studies have revealed four distinct molecular subgroups with divergent biology and clinical behaviour. An understanding of the regulatory circuitry governing the transcriptional landscapes of medulloblastoma subgroups, and how this relates to their respective developmental origins, is lacking. Here, using H3K27ac and BRD4 chromatin immunoprecipitation followed by sequencing (ChIP-seq) coupled with tissue-matched DNA methylation and transcriptome data, we describe the active cis-regulatory landscape across 28 primary medulloblastoma specimens. Analysis of differentially regulated enhancers and super-enhancers reinforced inter-subgroup heterogeneity and revealed novel, clinically relevant insights into medulloblastoma biology. Computational reconstruction of core regulatory circuitry identified a master set of transcription factors, validated by ChIP-seq, that is responsible for subgroup divergence, and implicates candidate cells of origin for Group 4. Our integrated analysis of enhancer elements in a large series of primary tumour samples reveals insights into cis-regulatory architecture, unrecognized dependencies, and cellular origins

    Строение приповерхностной части ледника в районе бухты Тала (Восточная Антарктида) по результатам георадарных работ сезона 2018/19 г.

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    The paper discusses the results of the ground-penetrating radar (GPR) survey carried out in February 2019 in the area of Thala Bay (Larsemann Hills, East Antarctica). Thala Bay is one of the strategic facilities of the Russian Antarctic Expedition (RAE) in the Progress station area as since 2019 heavy cargo has been unloaded here intended for the construction of new facilities at the Vostok station. Transportation of goods to the point of formation of logistic traverses takes place on ice tracks, whose safety must be evaluated taking into account the expanded system of crevasses. In addition, the current track is characterized by a significant slope of the terrain, which also complicates the relocation of heavy equipment.In February 2019, a GPR survey was carried out within the Thala Bay area to assess the possibility of organizing an alternative section of the route within it. According to the visual observations, this area was characterized by an extensive system of crevasses, the width of which at the surface reached 20-30 cm, and the prevailing longitudinal direction coincided with the direction of the route. The task of the geophysical survey was to map the crevasses not identified by visual inspection and to determine their morphology. According to the GPR data, it was shown that the crevasses within the site are located to the firn layer and are characterized by an irregular shape, significantly expanding at the deeper levels and reaching a width of 6 m. The results of the survey are illustrated with the scheme of the firn thickness which shows location of the crevasses. According to the recommendations of the authors, the section of the glacier is suitable for operation provided the glaciological situation using the GPR method is monitored annualy.В настоящей работе обсуждаются результаты георадиолокационных исследований, выполненных в районе российской антарктической станции Прогресс (оазис Холмы Ларсеманн, Восточная Антарктида) в сезон 64-й Российской антарктической экспедиции (РАЭ) в 2018/19 г. Изыскания проводились с целью оценки безопасности участка ледника в районе пункта разгрузки судов в бухте Тала для проложения в его пределах трассы передвижения тяжелой санно-гусеничной техники. По итогам георадарного профилирования в пределах исследуемого района выявлена сеть трещин, развитых в снежно-фирновой толще и достигающих максимальной ширины 6 м. Результаты работ проиллюстрированы схемой мощности снежно-фирновой толщи по участку работ и их распространения по состоянию на февраль 2019 г

    Анализ эффективности использования различных типов рекуператоров в нагревательных печах металлургического производства

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    The paper considers an operation of a metallic recuperator under conditions of heat exchange surface drift with scale and soot deposits. It has been shown that after one-year of its operation heat transfer factor decreases by 100–200 %. The paper contains recommendations for selection of a metallic recuperator.Рассмотрена реальная картина работы металлического рекуператора в условиях заноса поверхности теплообмена окалиной и сажестными отложениями. Показано, что по истечении первого года его работы коэффициент теплопередачи снижается на 100–200 %.Даны рекомендации по выбору металлического рекуператора
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