MSRP-FT: reliable resource sharing on multiprocessor mixed-criticality systems

Driven by applications such as autonomous vehicles, spacecrafts, robotics, and industrial automation, real-time systems are required to implement ever more complex functionalities with high performance, while maintaining conventional timing predictability, reliability, and cost efficiency. Necessarily, large-scale resource sharing on multiprocessor architectures has to be deployed. Unfortunately, existing protocols that manage shared resources and bound blocking delay have not considered reliability, i.e. how to handle faults. Contention over shared resources may be seriously aggravated by re-executions that are essential to satisfy a system's reliability requirements. Hence, there exists a significant barrier to applying resource sharing in the mission-critical sector. This paper fills that gap between reliability and resource sharing. Focusing on mixed-criticality systems (MCS), which widely exist in practice and make the problem more challenging, we propose a fault-tolerance solution which includes the first fault-tolerance multiprocessor resource sharing protocol (namely MSRP-FT) and a system execution model that supports the application of MSRP-FT in MCS. Our aim is to minimize blocking time while satisfying reliability requirements. A schedulability analysis is reported which can guarantee that timing constraints are respected. Compared to the state-of-the-art method, developed for fault-tolerant MCS without resource sharing, we improve the system schedulability by an average of 1.28× in stable modes and 1.1× during the mode switch

Quantification of extracellular matrix components in samples stored with the SCM protocol.

<p>Quantification of extracellular matrix components in samples stored with the SCM protocol.</p

Functional analysis of decellularised scaffolds.

<p>(A,B) Synchrotron analysis after 2 DET cycles confirmed extracellular matrix preservation in the lamina propria, submucosa and muscularis. (C) An intact basement membrane was detected across the entire scaffold segment. (D) Blood vessels were seen converging towards the scaffold in a spoked wheel manner after 10 days from placement on the CAM as confirmed by blinded quantification of the vessels compared to the negative control (**p< 0.01). (E) The maximum tensile stress at which the samples broke and the elasticity modulus remained comparable to fresh after decellularisation. (F) Characteristic stress-strain curves showing that by increasing the number of DET cycles the tensile stress at which the samples break remains the same as seen in E. DET = Detergent-Enzymatic Treatment, CAM = Chicken chorioallantoic membrane assay.</p

Composition and mechanical properties of decellularised scaffolds after storage.

<p>(A) Masson’s Trichrome staining demonstrated a progressive loss of architecture in 4°C-treated scaffolds. (B) Elastin staining showed maintenance of this protein in SCM scaffolds. Elastin was progressively lost in 4°C scaffolds. (C) Alcian Blue staining showed glycosaminoglycan maintenance in both storage methods. (D) Samples stored for 6 months with SCM maintained comparable ultimate tensile stress with 2 week-stored scaffolds despite a decreased Young's modulus with no impact on the maximum stress that the material could withstand. While 4°C samples at 2 weeks showed similar values to SCM, prolonged 4°C storage had a profound impact on the scaffold with a reduction of both values. *p<0.05 (bar = 100μm). SCM = slow cooling medium, 4°C = 4°C in PBS.</p

Decellularisation efficiency and scaffolds characterization.

<p>(A) Efficient cell removal after 2 DET cycles was evident by macroscopic appearance, H&E staining and DNA quantification. (B) Immunohistochemistry for extracellular matrix composition. Masson’s Trichrome and Picrosirius Red staining demonstrated collagen preservation in both submucosa and among muscle fibers (inset). Elastin Van Gieson staining showed elastic fibers in the submucosa, around blood vessels and surrounding muscle fascicles both in the fresh and DET tissues. Muscular elastin staining was reduced after 3 DET cycles (inset). Alcian Blue staining indicated glycosaminoglycan preservation (bar = 100μm). (C) Extracellular component quantification demonstrated a gradual decrease in collagen after the first and second DET cycle. Elastin decreased after 3 DET cycles. glycosaminoglycan were partially reduced by the first DET cycle. DET = Detergent-Enzymatic Treatment, MT = Masson’s Trichrome, PR = Picrosirius Red, EVG = Elastin Van Gieson, AB = Alcian Blue. *p<0.05; **p<0.01.</p

Macro- and microscopic appearance of stored decellularised scaffolds at 6 months.

<p>(A) Macroscopic appearances varied in the two protocols. (B) Scanning electron microscopy analysis. While SCM scaffolds demonstrated a good preservation of all oesophageal layers, in 4°C samples extracellular matrix was falling apart with signs of degradation. SCM = slow cooling medium, 4°C = 4°C in PBS.</p

Additional file 9: Table S8. of Whole exome sequencing coupled with unbiased functional analysis reveals new Hirschsprung disease genes

Characteristics of 116 ENS-related HSCR candidate genes. (XLSX 32 kb

Additional file 7: Table S6. of Whole exome sequencing coupled with unbiased functional analysis reveals new Hirschsprung disease genes

Gene recurrence and burden test. (XLSX 14 kb