Weak lasing in one-dimensional polariton superlattices

Bosons with finite lifetime exhibit condensation and lasing when their influx exceeds the lasing threshold determined by the dissipative losses. In general, different one-particle states decay differently, and the bosons are usually assumed to condense in the state with the longest lifetime. Interaction between the bosons partially neglected by such an assumption can smear the lasing threshold into a threshold domain—a stable lasing many-body state exists within certain intervals of the bosonic influxes. This recently described weak lasing regime is formed by the spontaneously symmetry breaking and phase-locking self-organization of bosonic modes, which results in an essentially many-body state with a stable balance between gains and losses. Here we report, to our knowledge, the first observation of the weak lasing phase in a one-dimensional condensate of exciton–polaritons subject to a periodic potential. Real and reciprocal space photoluminescence images demonstrate that the spatial period of the condensate is twice as large as the period of the underlying periodic potential. These experiments are realized at room temperature in a ZnO microwire deposited on a silicon grating. The period doubling takes place at a critical pumping power, whereas at a lower power polariton emission images have the same periodicity as the grating

Consensus for Multiple Unmanned Surface Vehicle (Musv) Systems with Markov Switching Topologies

This paper is concerned with sampled-data leader following consensus of multiple unmanned surface vehicle (MUSV) systems with random switching network topologies and wave-induced disturbance. By modelling the switching of network topologies with the use of a Markov process and considering the effect of wave-induced disturbance, a new sampleddata consensus control protocol is proposed. By employing an appropriate Lyapunov-Krosovskii function method and the weak infinitesimal operation, a novel stability criterion is derived, which ensures that the MUSV system can reach robustly leader-following consensus with H∞ performance satisfied. Based on this criterion, the Markov dependent switching consensus controller gains are obtained by solving a set of linear matrix inequalities. Finally, an illustrative example is given to verify the effectiveness of the proposed control scheme for MUSV systems

Consensus for Multiple Unmanned Surface Vehicle (Musv) Systems with Markov Switching Topologies

This paper is concerned with sampled-data leader following consensus of multiple unmanned surface vehicle (MUSV) systems with random switching network topologies and wave-induced disturbance. By modelling the switching of network topologies with the use of a Markov process and considering the effect of wave-induced disturbance, a new sampled-data consensus control protocol is proposed. By employing an appropriate Lyapunov-Krosovskii function method and the weak infinitesimal operation, a novel stability criterion is derived, which ensures that the MUSV system can reach robustly leader-following consensus with H∞ performance satisfied. Based on this criterion, the Markov dependent switching consensus controller gains are obtained by solving a set of linear matrix inequalities. Finally, an illustrative example is given to verify the effectiveness of the proposed control scheme for MUSV systems

Multilevel omics for the discovery of biomarkers in pediatric sepsis

ABSTRACT Severe sepsis causes organ dysfunction and continues to be the leading reason for pediatric death worldwide. Early recognition of sepsis could substantially promote precision treatment and reduce the risk of pediatric death. The host cellular response to infection during sepsis between adults and pediatrics could be significantly different. A growing body of studies focused on finding markers in pediatric sepsis in recent years using multi‐omics approaches. This narrative review summarized the progress in studying pediatric sepsis biomarkers from genome, transcript, protein, and metabolite levels according to the omics technique that has been applied for biomarker screening. It is most likely not a single biomarker could work for precision diagnosis of sepsis, but a panel of markers and probably a combination of markers detected at multi‐levels. Importantly, we emphasize the importance of group distinction of infectious agents in sepsis patients for biomarker identification, because the host response to infection of bacteria, virus, or fungus could be substantially different and thus the results of biomarker screening. Further studies on the investigation of sepsis biomarkers that were caused by a specific group of infectious agents should be encouraged in the future, which will better improve the clinical execution of personalized medicine for pediatric sepsis

Aligned carbon nanofibers-guided bone regeneration and orthopedic applications: A pilot study

In the present study, we fabricated electroconductive aligned carbon nanofibers (CNFs) as the nanofibers-guided bone regeneration scaffold. The CNFs were obtained from electrospun polyacrylonitrile nanofibers through two steps heat treatment. Aligned nanofibers were fabricated at high drum speed (2400 rpm). The fabricated CNFs were characterized regarding the morphology, crystallinity, carbon structure, wettability, electrical conductivity, hemocompatibility, cytocompatibility, and cell morphology. The results showed that the nanofibers obtained at 2400 rpm drum speed were aligned and electrical conductivity was dependent on the direction of conductivity measurement. The highest electrical conductivity (3.92 0.09 S.cm−1) was obtained at the measuring direction of that parallel to the axis of CNFs. The in vitro studies confirmed that the CNFs induced negligible hemolysis, indicating the hemocompatibility of CNFs. The cell viability assessment showed the biocompatibility of CNFs. The cell SEM images showed that MG-63 cells (an osteoblast-like cell line) were grown at a direction that parallels the axis of aligned CNFs, while the growth on the random CNFs was without a specific pattern. In conclusion, this study indicates that the fabricated aligned CNFs can be considered and the nanofibers-guided bone regeneration scaffold

Simultaneous Control over both Molecular Order and Long-Range Alignment in Films of the Donor–Acceptor Copolymer

Control over both molecular order and long-range alignment order in films of the donor–acceptor copolymer of 3,6-bis­(thiophen-2-yl)-<i>N</i>,<i>N</i>′-bis­(2-octyl-1-dodecyl)-1,4-dioxo-pyrrolo­[3,4-<i>c</i>]­pyrrole and thieno­[3,2-<i>b</i>]­thiophene (PDBT-TT) was demonstrated via off-center spin-coating (OCSC) from its blend solution with polystyrene (PS). It was found that the dichroic ratio (DR) of OCSC blend films was dependent on both the physical process of spin-coating and the effect of PS chains. The highest DR of 2.75 was obtained via OCSC from the blend solution in oDCB at 1500 rpm. Meanwhile, both the intrachain and interchain molecular order were improved in blend films compared with neat ones, which were indicated by the red-shift of the max absorption, enhanced J-aggregation absorption, and smaller π–π stacking distance (from 3.77 to 3.70 Å). According to the results of the investigation into the macro anisotropy, micro morphology, solution rheology properties, and photophysics features of films, an overall mechanism of simultaneous control over molecular and long-range order of D–A copolymer films was proposed. On the one hand, a larger viscosity and the pseudoplastic nature of the solution tuned by choosing good solvents with high boiling points and adding PS resulted in a better chain disentanglement, better shear transfer, and a slower contact line receding velocity to induce an enhanced alignment of chains and thus fibrillar aggregates. Also, the critical contact line receding velocity for alignment dominated by the solvent evaporation rate accounted for the variation of DR with OCSC rates. A vertical phase separation accompanying the formation of aligned fibrils during OCSC was also confirmed due to the friction shear between air and solution surface. On the other hand, the negligible dependence of the blend OCSC film’s photophysical and morphological features on the solvent suggested the critical role of PS in determining the better intrachain conjugation in blend films, which was attributed to multiple reasons, like limited phase separation room, a coil-toward conformation promotion, and a high surface energy. Furthermore, the enhanced π-attraction and smaller steric hindrance induced by improved intrachain conjugation accounted for the smaller π–π stacking distance in the blend films than that in the neat ones