Observability Robustness under Sensor Failures: Complexities and algorithms

The problem of determining the minimal number of sensors whose removal destroys observability of a linear time invariant system is studied. This problem is closely related to the ability of unique state reconstruction of a system under adversarial sensor attacks, and the dual of it is the inverse to the recently studied minimal controllability problems. It is proven that this problem is NP-hard both for a numerically specific system, and for a generic system whose nonzero entries of its system matrices are unknown but can take values freely (also called structured system). Two polynomial time algorithms are provided to solve this problem, respectively, on a numerical system with bounded maximum geometric multiplicities, and on a structured system with bounded matching deficiencies, which are often met by practical engineering systems. The proposed algorithms can be easily extended to the case where each sensor has a non-negative cost. Numerical experiments show that the structured system based algorithm could be alternative when the exact values of system matrices are not accessible.Comment: 8 pages, 2 figures, add some materials, fix some type error

Dexmedetomidine post-treatment attenuates cardiac ischaemia/reperfusion injury by inhibiting apoptosis through HIF-1α signalling.

Hypoxia-inducible factor 1α (HIF-1α) plays a critical role in the apoptotic process during cardiac ischaemia/reperfusion (I/R) injury. This study aimed to investigate whether post-treatment with dexmedetomidine (DEX) could protect against I/R-induced cardiac apoptosis in vivo and in vitro via regulating HIF-1α signalling pathway. Rat myocardial I/R was induced by occluding the left anterior descending artery for 30 minutes followed by 6-hours reperfusion, and cardiomyocyte hypoxia/reoxygenation (H/R) was induced by oxygen-glucose deprivation for 6 hours followed by 3-hours reoxygenation. Dexmedetomidine administration at the beginning of reperfusion or reoxygenation attenuated I/R-induced myocardial injury or H/R-induced cell death, alleviated mitochondrial dysfunction, reduced the number of apoptotic cardiomyocytes, inhibited the activation of HIF-1α and modulated the expressions of apoptosis-related proteins including BCL-2, BAX, BNIP3, cleaved caspase-3 and cleaved PARP. Conversely, the HIF-1α prolyl hydroxylase-2 inhibitor IOX2 partly blocked DEX-mediated cardioprotection both in vivo and in vitro. Mechanistically, DEX down-regulated HIF-1α expression at the post-transcriptional level and inhibited the transcriptional activation of the target gene BNIP3. Post-treatment with DEX protects against cardiac I/R injury in vivo and H/R injury in vitro. These effects are, at least in part, mediated via the inhibition of cell apoptosis by targeting HIF-1α signalling

Noncollinearity-modulated electronic properties of the monolayer CrI3_3

Introducing noncollinear magnetization into a monolayer CrI$_3$ is proposed to be an effective approach to modulate the local electronic properties of the two-dimensional (2D) magnetic material. Using first-principles calculation, we illustrate that both the conduction and valence bands in the monolayer CrI$_3$ are lowered down by spin spiral states. The distinct electronic structure of the monolayer noncollinear CrI$_3$ can be applied in nanoscale functional devices. As a proof of concept, we show that a magnetic domain wall can form a one-dimensional conducting channel in the 2D semiconductor via proper gating. Other possible applications such as electron-hole separation and identical quantum dots are also discussed

Azido­{2-[bis­(2-hy­droxy­eth­yl)amino]­ethano­lato-κ4 N,O,O′,O′′}cobalt(II)

In the title complex, [Co(C6H14NO3)(N3)] or [Co(teaH2)N3], the CoII atom resides in a trigonal–bipymidal O3N2 environment formed by three O atoms and one N atom from a simply deprotonated tetra­dentate triethano­lamine ligand, and one N atom from an azide ligand. The O atoms define the equatorial plane whereas both N atoms are in axial positions. The mononuclear units are linked through O—H⋯O hydrogen-bonding inter­actions between the ethanol OH groups and the ethano­late O atom of a neighbouring complex into chains running parallel to [010]

Electrochemical codeposition of nickel oxide and polyaniline

Nickel oxide (NiOx) and polyaniline (PAni) were electrocodeposited from NiSO4 and aniline through cyclic voltammetric scans to afford PAni–NiOx composite film at controlled pH environment. The electrochemical activities of the film were investigated by cyclic voltammetry in 0.1 M NaOH and 0.1 M H2SO4, respectively. Typical redox couples of PAni in 0.1 M H2SO4 appeared at approximately 0.2 and 0.4 V vs. saturated calomel electrode (SCE); Ni(II)/Ni(III) redox couple was observed at approximately 0.4 V vs. SCE in 0.1 M NaOH. The morphologies and elemental components of the films were inspected by scanning electron microscopy and energy dispersive X-ray diffraction. The stability of nickel oxide in the films was found to be enhanced against acidic environments. Electrochemical catalytic behavior of NiOx within the composite film was conserved and demonstrated by catalytic oxidation of methanol and ethanol