Nessys:A new set of tools for the automated detection of nuclei within intact tissues and dense 3D cultures

Methods for measuring the properties of individual cells within their native 3D environment will enable a deeper understanding of embryonic development, tissue regeneration, and tumorigenesis. However, current methods for segmenting nuclei in 3D tissues are not designed for situations in which nuclei are densely packed, nonspherical, or heterogeneous in shape, size, or texture, all of which are true of many embryonic and adult tissue types as well as in many cases for cells differentiating in culture. Here, we overcome this bottleneck by devising a novel method based on labelling the nuclear envelope (NE) and automatically distinguishing individual nuclei using a tree-structured ridge-tracing method followed by shape ranking according to a trained classifier. The method is fast and makes it possible to process images that are larger than the computer's memory. We consistently obtain accurate segmentation rates of >90%, even for challenging images such as mid-gestation embryos or 3D cultures. We provide a 3D editor and inspector for the manual curation of the segmentation results as well as a program to assess the accuracy of the segmentation. We have also generated a live reporter of the NE that can be used to track live cells in 3 dimensions over time. We use this to monitor the history of cell interactions and occurrences of neighbour exchange within cultures of pluripotent cells during differentiation. We provide these tools in an open-access user-friendly format

Nuclear organisation and replication timing are coupled through RIF1-PP1 interaction

Three-dimensional genome organisation and replication timing are known to be correlated, however, it remains unknown whether nuclear architecture overall plays an instructive role in the replication-timing programme and, if so, how. Here we demonstrate that RIF1 is a molecular hub that co-regulates both processes. Both nuclear organisation and replication timing depend upon the interaction between RIF1 and PP1. However, whereas nuclear architecture requires the full complement of RIF1 and its interaction with PP1, replication timing is not sensitive to RIF1 dosage. The role of RIF1 in replication timing also extends beyond its interaction with PP1. Availing of this separation-of-function approach, we have therefore identified in RIF1 dual function the molecular bases of the co-dependency of the replication-timing programme and nuclear architecture

Research on Index System for Disabled Elders Evaluation and Grey Clustering Model Based on End-point Mixed Possibility Functions

The file attached to this record is the Publisher's final version.An operational ability assessment system for older adults is of great help to address health and social challenges for ageing. In this paper, the main problems in currently available ADL and ability evaluation systems have been analyzed. The basic principles to build an index system for disability elders evaluation have been put forwarded. Then，an improved Barthel index system for ADL evaluation and a new older adults ability evaluation system consisted of 4 first-level indexes and 14 secondary indexes based on experts’ opinion and the ability assessment system for older adults by Ministry of Civil Affairs of China have been built. The grey clustering model based on end-point mixed triangular possibility function has been introduced. And three living examples of adults’ disability evaluation have been conducted. It is confirmed clearly that the three older adults belong to different categories of "severe disability", "mild disability", and "ability passable" respectively. The research results can be used as reference for government to formulate the elderly-care policies, to run and allocate the elderly-care resources, as well as reference for various nursing or elderly-care institutions

Investigating how RIF1 coordinates the timing of replication and the spatial distribution of late-replicating genomic regions

In eukaryotes, the genome is organised into domains which are replicated at different times during S-phase. The order of replication of these domains, known as the “replication-timing (RT) program”, is transmitted from one cell cycle to the next. It is cell-type specific and changes during cell fate transition. The RT program is closely related to the 3-dimensional (3D) nuclear organisation. The co-variation of the RT program and nuclear architecture during cell fate commitment and the coincidence of their re-establishment in early G1 phase have promoted the hypothesis that nuclear organisation might contribute to the establishment of the RT program, or vice versa. During my PhD, I have contributed to our recent published work showing that RIF1 serves as a hub to regulate both the RT program and nuclear architecture via, at least partially, RIF1-PP1 interaction. I have then focused on a particular aspect of RIF1-dependent nuclear organisation, namely understanding how and why RIF1, assembled in large domains called RIF1-associated domains (RADs), ensures the peripheral localisation of late-replicating genomic regions. We have identified two different types of RADs: RADs with strong association to LAMIN-B1(RADs-LBhigh) and RADs less frequently associated with LAMIN-B1(RADs-LBlow). While the former are more resistant to the loss of RIF1, the RADs-LBlow are more sensitive to RIF1 depletion, indicated by both advanced RT and internalisation within the nucleus. This suggests that RIF1 is involved in anchoring RADs-LBlow to the nuclear periphery. To test whether peripheral localisation could determine late RT, here, I present the establishment of tethering platforms to manipulate nuclear localisation, followed by the investigation of RT. The preliminary result suggests that forced nuclear peripheral position is capable of dictating late RT. Moreover, my work also provides preliminary data suggesting that RIF1 is also involved in regulating cell cycle dynamics of H3S10ph, dependent on RIF1-PP1 interaction, and that RIF1 depletion also causes reduction of HP1g association to some of the RADs. This leads to the hypothesis that both H3S10ph and HP1g could contribute to RIF1’s function in regulating nuclear organisation. Thus, this study provides further molecular understanding of the mechanisms that underly the connection between the RT program and nuclear organisation through RIF1

Pose measurement model of space cooperative target capture based on zoom vision system

In view of the mission of the cooperative target capture with the space manipulator, this article proposes to establish pose measurement model of the space cooperative target capture based on thick lens model for the first time. First, a ground simulation system is established for the cooperative target capture with the space manipulator based on the zoom vision system, coordinate system is defined, and pose calculation process is given. Then, space coordinate measurement model and pose calculation model are established for the system. Finally, the simulation experiments are conducted and the results validate the algorithm model and the high accuracy of measurement

Research on Vegetation Cover Changes in Arid and Semi-Arid Region Based on a Spatio-Temporal Fusion Model

Vegetation dynamics in arid and semi-arid regions have an important impact on carbon cycle, water cycle, and energy exchange at local, regional, and global scales. Therefore, it is of great significance for scientists to grasp the changes of vegetation cover in arid and semi-arid regions timely and accurately. Based on this, the applicability of ESTARFM model in the complex terrain area of arid and semi-arid Xinjiang was explored using Landsat and MODIS data fusion, and the overall change characteristics of vegetation cover (FVC) and the distribution and change patterns of different terrains in the study area in the past 15 years were analyzed by combining the dimidiate pixel model, unary linear regression and digital elevation model. The results show that: (1) the NDVI data fused by ESTARFM Model has high consistency with the real NDVI data, and it can be used for subsequent FVC estimation. (2) From 2006 to 2020, the inter FVC was at a high level as a whole, and the average annual FVC showed a weak increasing trend in fluctuation; there are obvious differences in spatial distribution, which is characterized by high distribution in the north and low in the south. (3) The improved area of vegetation cover in the study area is greater than the degraded area, accounting for 52.3% and 47.7% respectively; (4) In the elevation range of 2000 to 3500 m, the FVC showed a slight degradation trend on 25° to 45° slopes and south and southeast slopes, and the rest showed a slight improvement trend. ESTARFM-based model enables monitoring of vegetation cover changes in complex terrain areas of the arid and semi-arid regions in Xinjiang over a long time series. The overall FVC level in the study area is high, and there both are serious degradation and improvement phenomena