Tiangong space station | EPFL Graph Search

Tiangong (), officially the Tiangong space station (), is a permanently crewed space station constructed by China and operated by China Manned Space Agency in low Earth orbit between above the surface. It is China's first long-term space station, part of the Tiangong program and the core of the "Third Step" of the China Manned Space Program; it has a pressurised volume of 340 m3 (12,000 cu ft), slightly over one third the size of the International Space Station. The construction of the station is based on the experience gained from its precursors, Tiangong-1 and Tiangong-2. The first module, the Tianhe ("Harmony of the Heavens") core module, was launched on 29 April 2021, followed by multiple crewed and uncrewed missions and two more laboratory cabin modules Wentian ("Quest for the Heavens") launched on 24 July 2022 and Mengtian ("Dreaming of the Heavens") launched on 31 October 2022. The space station aims to provide opportunities for space-based experiments and a platform for building capacity for scientific and technological innovation. The names used in the space program, previously all chosen from the revolutionary history of the People's Republic, have been replaced with mystical-religious ones. Thus, the new Long March launch vehicles were renamed Divine Arrow (神箭), space capsule Divine Vessel (神舟), spaceplane Divine Dragon (神龙), land-based high-power laser Divine Light (神光), and supercomputer Divine Might (神威). These poetic names continue as the first, second, third, fourth, fifth and future probes of the Chinese Lunar Exploration Program are called Chang'e – after the Moon goddess. The name "Tiangong" means "heavenly palace". Across China, the launch of Tiangong-1 was reported to have inspired a variety of feelings, including love poetry. The rendezvous of the space vehicles has been compared to the reunion of the cowherd and the weaver girl. Wang Wenbao, director of the China Manned Space Agency (CMSA), told a news conference in 2011: "Considering past achievements and the bright future, we feel the manned space programme should have a more vivid symbol, and that the future space station should carry a resounding and encouraging name.

Towards patient-tailored interventions for stroke recovery: graph theoretical approaches and modeling of non-invasive brain stimulation

Giorgia Giulia Evangelista

Stroke is a disease that causes the death of precious brain cells that will never grow back and which will affect one in four humans at some point in their life. While therapies and treatments for this debilitating condition are fairly standard, their outcomes are highly heterogeneous, with deficits all too often leading to permanent disability. These unsatisfactory outcomes point to the need for a paradigm shift towards precision medicine, where therapies and treatments are tailored to individual patients. This in turn requires a better understanding of the mechanisms underlying post-stroke impairment and recovery. Recent technological innovations provide an unprecedented opportunity to acquire a detailed picture of the anatomy and electrophysiology of the human brain non-invasively. Therefore, we apply multimodal methodologies to investigate the inner workings of the stroke-affected brain with a view to establishing biomarkers and creating stratifications that maximize the effectiveness of stroke therapy by making it personalized.In the first part of this thesis, network-theoretic models of the brain known as connectomes are created, under the assumption that these provide sufficiently detailed information about the individual patient to inform personalized recommendations. In particular, we leverage existing knowledge about how brain networks are organized into specialized modules connected by a "rich-club" of hubs. In a novel contribution to the field of connectomics, we combine these connectomes with detailed images of the lesion to obtain a network-theoretic lesion profile and a map of the non-lesioned part of the network, which we expect to be a better reflection of true brain connectivity. Using this methodology, we establish that the rich-club, in addition to being a source of network robustness, is also a source of vulnerability in that attacks against it lead to poor behavioral outcomes disproportionate to the size of the attacks.The creation of in-silico simulation of individual patients presents a great opportunity to quickly experiment with treatments, making it a potential game-changer in medical research. However, current technology is not able to faithfully capture the complexity of a whole human brain. The complex brain abnormalities inherent to stroke only add to the difficulty of the challenge. Any models one might wish to create must strike a balance between technological feasibility and sensitivity to inter-patient variability across a large parameter space. In the second part of this thesis, we investigate whether one major source of inter-patient variability, namely the size and location of the lesion, induces substantial variability in the effects of non-invasive brain stimulation to be included as factors in the design of stimulation protocols. Based on our modeling of the stimulation, personalizing stimulation protocols by taking the lesion into account produces little added value, except possibly when one is targeting brain areas close to the lesion and the lesion is significantly large.The proposed studies represent a step of the march towards precision medicine, by examining sources of variability in stroke patients and by associating them with variability in some outcomes of interest. Each step of this march brings stroke therapy farther from the status quo of homogeneous treatments and heterogeneous outcomes and closer to the ideal of heterogeneous treatments and homogeneously positive outcomes.

EPFL2022

Towards patient-tailored interventions for stroke recovery: graph theoretical approaches and modeling of non-invasive brain stimulation

Giorgia Giulia Evangelista

EPFL2022