Rosette-forming glioneuronal tumours: two case reports and a review of the literature

Rosette-forming glioneuronal tumour (RGNT) is a rare central nervous system (CNS) neoplasm that typically arises in the fourth ventricle. It is even more uncommon to arise outside the midline. In this paper, we report 2 cases of RGNT: one located in the fourth ventricle (a typical site), and the other in the right cerebellar hemisphere (a rare site). Both cases were misdiagnosed on imaging, and the results were inconsistent with the pathological diagnosis. The aim of the article is to deepen medical practitioners’ understanding of RGNT by learning from these 2 cases, summarizing cases located in the cerebellar hemispheres and systematically reviewing RGNT.

Study on Diversity and Protection Countermeasures of Zhongshan Park in Wuhan City

Park green space is an important part of garden green space, concentrated expression of the diversity of urban plants. In order to explore the diversity of plants in the park, a typical site in Zhongshan Park in Wuhan was selected for this survey. The species importance, richness index, diversity index and evenness index were used to analyze the characteristics of plant diversity.There are a total of 184 plants of 114 genera and 64 families in Wuhan Zhongshan Park. Among them, there are 86 species of plants of 40 families and 64 genera, 60 species of plants of 26 families and 38 genera, and 26 species of herbs, 11 families and 15 genera.The richness was herb layer > tree layer > shrub layer.Pielou uniformity was herb layer > tree layer > shrub layer;Shannon-wiener diversity was herb layer > tree layer > shrub layer.Simpson diversity was herb layer > tree layer > shrub layer.The diversity of herbaceous plants in the park is high, and the index of shrub layer is generally low, with few species. Plants in the park grow well, some plants are not evenly distributed.

Concentrations and sources of persistent organochlorine residues in the sediments and soils from an industrially impacted area in Anhui, China

In this study, a typical site that had been contaminated by the chemical industry in the past was selected for investigation. To reveal the pollution status, 18 organochlorine pesticides (OCPs) and seven polychlorinated biphenyls (PCBs) in the surface soil and sediment samples were analysed by gas chromatography-mass spectrometry (GC-MS). The levels of the persistent organochlorine residues in the sediment ranged from 44.59–143.29 ng/g, whereas they were 13.94–97.91 ng/g in the soil. A principal component analysis identified that PCBs and dichlorodiphenyltrichloroethanes (DDTs) were the primary sources of the organochlorine residues in the study area. The p,p'-DDT/(p,p'-DDE + p,p'-DDD) values were all below 1, which indicated that the historical inputs of the technical DDT and dicofol were the major sources of DDTs rather than recent inputs. The composition diversity of the hexachlorocyclohexane (HCH) isomers showed that the main sources in the soil were the past use of pesticides, whereas the sediment sources might be due to the historical use of technical HCHs and recent lindane inputs. The ecological risk assessment showed that γ-HCH could pose the highest risks for benthic organisms, followed by DDTs and heptachlor epoxide. These compounds are known to bio-accumulate in fatty tissues. Therefore, routine monitoring of the persistent organochlorine residues in the area is needed and the health risks to local residents should be assessed.

Assessment of the efficiency of aircraft control data preparation by the method of technological sites

Nowadays methods for solving the problem of estimating the temporal characteristics of data processing are well studied and based on the timing performed operations, the use of the network graph, the construction of the spanning tree, etc. However, in solving some problems of automating controls, there may be difficulties associated with modeling the information processing and obtaining adequate input data for calculating the indicator of the timeliness of the system function implementation. The article considers general issues of assessing the properties determining the quality of aircraft flight data, its feasibility and timeliness. A new approach associated with the model "the presence of exactly one error in the generated data volume" is proposed for assessing the feasibility of aircraft flight data. This model is applicable only in the case when the control of feasibility is carried out for the entire set of necessary data. For timeliness index assessment, it is proposed to present the structure of the automated data preparation system in the form of a sequence of technological sites. Having determined the execution time of functional tasks by elements of a typical site and probabilities of data distortion, it is possible to calculate similar indicators for each elementary process included in the data preparation process and the system as a whole. An elementary data preparation process, the essence of which is to update the system database is considered as an example. This stage is the most representative, since all elements of the technological site are involved in its implementation.

The study of stress state and nechanism of rock massif deformation upon the formation of technonatural karst collapses

The paper deals with the assessment of stress-strain state variation in rock massifs upon the formation of displacement moulds and surface sinkholes in the undermined areas of Verkhnekamskoe potassium salt deposit in Perm krai, Russia. Engineering geological conditions, as well as natural and technogenic factors influencing the development of hazardous geological processes are described by the example of one typical site of the deposit. Methodical issues of the development of geomechanical model for this site and compilation of finite-element calculation scheme with selecting calculation parameters of rock properties and boundary conditions of the calculation area are considered. Regularities in the variation of stress fields and rock massif deformations upon cutting mines at one depth are considered. The possible mechanisms of deformation and destruction of karstified rock massifs upon the formation of technonatural sinkholes on the earth surface are described. The results of the study are significant for predicting hazardous processes and undertaking protective measures.