Based on fuzzy mathematics theory, this paper proposes a fuzzy multi-objective optimization model with related constraints to minimize the total economic cost and network loss of microgrid. Uncontrollable microsources are considered as negative load, and stochastic net load scenarios are generated for taking the uncertainty of their output power and load into account. Cooperating with storage devices of the optimal capacity controllable microsources are treated as variables in the optimization process with the consideration of their start and stop strategy. Chaos optimization algorithm is introduced into binary particle swarm optimization (BPSO) to propose chaotic BPSO (CBPSO). Search capability of BPSO is improved via the chaotic search approach of chaos optimization algorithm. Tests of four benchmark functions show that the proposed CBPSO has better convergence performance than BPSO. Simulation results validate the correctness of the proposed model and the effectiveness of CBPSO.

Although π–π interactions have been studied for several decades, the quantification of the strength of π–π interactions in a macromolecule remains a big challenge. Herein, we utilize single-molecule atomic force microscopy and steered molecular dynamics simulations to study the π–π interactions in polystyrene (PS). It is found that in high vacuum, the single-chain mechanics of PS differs largely from that of polyethylene (PE). Accordingly, the strength of intrachain π–π interactions in PS is estimated to be 0.7 kcal/(mol stack), which is much lower than that in a small-molecule system (benzene dimer, 2–3 kcal/(mol stack)). Further study shows that in high vacuum, there are two types of π–π stacking in the single PS chain, i.e., the every-other-moiety (E) type and the adjacent-moiety (A) type. Upon force stretching, a transition from E-type to A-type π–π stacking can be observed.

It is generally accepted that water is deeply involved in the structures and functions of DNA and proteins. For polysaccharides, however, the role of water remains poorly understood. Amylose and natural cellulose (NC) are two polysaccharides with similar molecular structures but different linkages (α or β) between the pyranose rings. In this study, the effects of H-bonds on the single-molecule mechanics and affinity for water of amylose and NC are explored by single-molecule atomic force microscopy (AFM) and molecular dynamics (MD) simulations, respectively. The experimental results show that the single-molecule mechanics of both amylose and NC are dependent on the solvent polarity. Accordingly, the status of H-bonds of each polysaccharide can be inferred. We find that the two polysaccharides present the same status of H-bonds in a given organic solvent: the intrachain H-bonds can be formed in a nonpolar solvent (nonane), while they are completely prohibited in a highly polar solvent (dimethyl sulfoxide, DMSO). However, the statuses of H-bonds differ largely in water, where NC can form more intrachain H-bonds than amylose. This finding, which is supported by MD simulations, indicates that NC is more hydrophobic than amylose at the single-molecule level. These results reveal that water is a special solvent for these two polysaccharides: Both mechanics and affinity for water of them can be effectively affected by water through regulation of the H-bonds. The present study provides new insight into the role of water (the key environment of organisms) in the structures and functions of polysaccharides.

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Sleep disturbance frequently occurs in patients with mild cognitive impairment (MCI) and appears to be involved in the cellular and molecular mechanisms of cognitive decline. The aim of this systematic review is to clarify whether patients with MCI demonstrate alterations in certain sleep parameters: total sleep time (TST), sleep efficiency (SE), sleep latency (SL), rapid eye movement latency (REML), percent of rapid eye movement (REM%), arousal index (AI), wake after sleep onset (WASO), slow-wave sleep (SWS), periodic leg movement in sleep (PLMS), and cyclic alternating pattern (CAP) through polysomnography (PSG) and actigraphy. Databases including PubMed, Web of Science, Embase, ScienceDirect, Cochrane, CBM, CNKI, Wanfang Data, and VIP were searched up to January 2016 to collect literature on the correlation between sleep disturbance and MCI as assessed by objective measures. Meta-analysis was conducted using the Review Manager 5.3 software. A total of ten case-control studies involving 225 MCI patients and 235 healthy elders (HE) were deemed eligible and included in our meta-analysis. Every type of sleep disturbance was present in our studies with significant differences in the MCI subtypes. Compared with HE, overall MCI patients as a group expressed more SL and less SE; MCI patients showed less TST and SE and more SL and CAP; patients with amnestic mild cognitive impairment (aMCI) had less AI; patients with non-amnestic mild cognitive impairment (naMCI) had more TST and less AI. Patients with naMCI expressed more AI than those with aMCI. The results indicate that MCI patients might experience more serious sleep disturbance and that different MCI subtypes have different patterns of sleep disturbance.