A novel predict-then-optimize method for sustainable bike-sharing management: a data-driven study in China.

Sustainable operations management will appeal to the post-pandemic world. As the economy recovers, the surging demand for low-carbon bike-sharing has led to exacerbated mismatch in urban transportation. It is a serious challenge to optimize the reallocation schedule of sharing bikes among multiple positions in a network. To address the problem, we develop a novel predict-then-optimize method consisting of a data-driven robust optimization model and a branch-and-price algorithm. The optimization model derives the predicted demand surplus of each position based on historical data, enabling the optimal reallocation schedule in the network at minimum operational costs. Based on the prediction, the branch-and-price algorithm can find out the best routes of assigning bikes to specific positions that further improves transportation efficiency. Finally, we deploy the predict-then-optimize method to a realistic bike-sharing network in one major city of China. The computational results demonstrate that our method can significantly save the cost of operations and reduce the waste of resources. Therefore, the novel predict-then-optimize method has a great potential to facilitate the sustainable development of bike-sharing systems in urban transportation.

Electroconvulsive therapy changes temporal dynamics of intrinsic brain activity in depressed patients.

Electroconvulsive therapy (ECT) has been demonstrated to be effective in treating depressed patients. Previous neuroimaging studies have focused mainly on alterations in static brain activity and connectivity to study the effects of ECT in depressed patients. However, it remains unclear whether the temporal dynamics of brain activity are associated with mechanisms of ECT in depressed patients. We measured the dynamics of spontaneous brain activity using dynamic amplitude of low-frequency fluctuation (dALFF) in healthy controls (n = 40) and patients diagnosed with unipolar depression (UD, n = 36) or bipolar disorder (BD, n = 9) before and after ECT. Furthermore, the temporal variability of intrinsic brain activity (iBA) was quantified as the variance of dALFF across sliding window. In addition, correlation analysis was performed to investigate the relationships among dALFF, depressive symptoms, and cognitive function in depressed patients. We lack second resting-state functional magnetic resonance imaging (rs-fMRI) data for healthy controls. After ECT, patients showed decreased brain dynamics (less temporal variability) in the right dorsal anterior cingulate cortex (dACC) and the right precuneus, whereas they showed increased brain dynamics in the bilateral superior medial frontal cortex (mSFC). No significant correlation was found between the dALFF and clinical variables in depressed patients. Our findings suggest that right dACC, right precuneus, and bilateral mSFC play an important role in response to ECT depressed patients from the perspective of dynamic local brain activity, indicating that the dALFF variability may be useful in further understanding the mechanisms of ECT's antidepressant effects.

Decline in executive function in patients with white matter hyperintensities from the static and dynamic perspectives of amplitude of low-frequency fluctuations.

Cognitive impairments are characteristics of patients with white matter hyperintensities (WMHs), and hypoperfusion is currently a relatively recognized mechanism of WMHs. Brain activity is closely coupled to the regulation of local blood flow. This study aimed to investigate the abnormal local brain activity of patients with WMHs from the viewpoint of the static amplitude of low-frequency fluctuations (sALFF) and dynamic amplitude of low-frequency fluctuations (dALFF). Seventy-four patients with WMHs and 35 healthy controls (HCs) were included. Based on the Fazekas scale, patients with WMHs were further divided into a mild WMH group (n = 33, Fazekas score 1-2) and moderate-severe WMH group (n = 41, Fazekas score 3-6). The sALFF and dALFF values were calculated separately and neuropsychological tests including the Montreal Cognitive Assessment (MoCA), Auditory Verbal Learning Test (AVLT), Trail Making Test (TMT), and Boston Naming Test (BNT) were completed by all participants. Patients with WMHs showed increased sALFF and dALFF values in the bilateral thalamus and decreased performance in the MoCA test, AVLT-immediate, AVLT-delay, AVLT-recognition, TMT-A, and BNT. The dALFF values in the bilateral thalamus was correlated with the MoCA in HCs. The sALFF values in the bilateral thalamus correlated with TMT-B in patients with WMHs. Patients with WMHs showed abnormal brain activity and decreased functional stability of the bilateral thalamus, which may be a potential mechanism of decreased executive function.

The Cerebellum Is Related to Cognitive Dysfunction in White Matter Hyperintensities.

OBJECTIVE: White matter hyperintensities (WMHs) on magnetic resonance imaging (MRI) is frequently presumed to be secondary to cerebral small vessel disease (CSVD) and associated with cognitive decline. The cerebellum plays a key role in cognition and has dense connections with other brain regions. Thus, the aim of this study was to investigate if cerebellar abnormalities could occur in CSVD patients with WMHs and the possible association with cognitive performances. METHODS: A total of 104 right-handed patients with WMHs were divided into the mild WMHs group (n = 39), moderate WMHs group (n = 37), and severe WMHs group (n = 28) according to the Fazekas scale, and 36 healthy controls were matched for sex ratio, age, education years, and acquired resting-state functional MRI. Analysis of voxel-based morphometry of gray matter volume (GMV) and seed-to-whole-brain functional connectivity (FC) was performed from the perspective of the cerebellum, and their correlations with neuropsychological variables were explored. RESULTS: The analysis revealed a lower GMV in the bilateral cerebellum lobule VI and decreased FC between the left- and right-sided cerebellar lobule VI with the left anterior cingulate gyri in CSVD patients with WMHs. Both changes in structure and function were correlated with cognitive impairment in patients with WMHs. CONCLUSION: Our study revealed damaged GMV and FC in the cerebellum associated with cognitive impairment. This indicates that the cerebellum may play a key role in the modulation of cognitive function in CSVD patients with WMHs.

Abnormal Degree Centrality in White Matter Hyperintensities: A Resting-State Functional Magnetic Resonance Imaging Study.

Background: White matter hyperintensities (WMHs) are a common occurrence with aging and are associated with cognitive impairment. However, the neurobiological mechanisms of WMHs remain poorly understood. Functional magnetic resonance imaging (fMRI) is a prominent tool that helps in non-invasive examinations and is increasingly used to diagnose neuropsychiatric diseases. Degree centrality (DC) is a common and reliable index in fMRI, which counts the number of direct connections for a given voxel in a network and reflects the functional connectivity within brain networks. We explored the underlying mechanism of cognitive impairment in WMHs from the perspective of DC. Methods: A total of 104 patients with WMHs and 37 matched healthy controls (HCs) were enrolled in the current study. All participants underwent individual and overall cognitive function tests and resting-state fMRI (rs-fMRI). WMHs were divided into three groups (39 mild WMHs, 37 moderate WMHs, and 28 severe WMHs) according to their Fazekas scores, and the abnormal DC values in the WMHs and HCs groups were analyzed. Results: There was a significant difference in the right inferior frontal orbital gyrus and left superior parietal gyrus between the WMHs and HCs groups. The functional connectivity between the right inferior frontal orbital gyrus and left inferior temporal gyrus, left superior parietal gyrus, and left parietal inferior gyrus was also different in the WMHs group. Conclusion: The change in DC value may be one of the underlying mechanisms of cognitive impairment in individuals with WMHs, which provides us with a new approach to delaying cognitive impairment in WMHs.

Enhanced Flexible Poly(vinylidene fluoride-trifluorethylene) Piezoelectric Nanogenerators by SnSe Nanosheet Doping and Solvent Treatment.

Organic piezoelectric nanogenerators (PENGs) with light weight, good flexibility, and simple processing are promising in mechanical energy conversion. Here, a high-output polymer PENG composed of a poly(vinylidene fluoride-trifluorethylene)/SnSe nanosheet (NS) nanocomposite film has been fabricated and tested. After a treatment with mixed solvents of N,N-dimethylformamide and 1,1,2,2-tetrachloroethane (TCE), the optimal nanocomposite PENG exhibits high piezoelectric properties with a piezoelectric coefficient (d33) of 25.06 pC·N-1, a prominent open-circuit voltage (Voc) of 15.36 V·cm-2, and a short-circuit current (Isc) of 1.02 µA·cm-2. Moreover, the PENG can generate an output power density of up to 10.72 µW·cm-2 under a vertical force of 50 N. The attractive piezoelectric performance results from the doping of SnSe NSs with a high piezoelectric coefficient and also the increased ß-phase ascribed to the introduction of nucleating agent NSs and the TCE solvent. The PENGs reveal great application potentials in consumer electronics.

Altered neural activity in the reward-related circuit and executive control network associated with amelioration of anhedonia in major depressive disorder by electroconvulsive therapy.

Anhedonia is a core characteristic of depression, the amelioration of which accounts for depressive symptom improvement. Electroconvulsive therapy (ECT) has been shown remarkable antidepressive effect, however, less is known about the effect of ECT on anhedonia and its underlying neural mechanism. Herein, we investigated local and global intrinsic brain functional alterations during the resting state in 46 patients with pre- and post-ECT major depressive disorder using the amplitude of low-frequency fluctuations (ALFF) and degree centrality (DC) approach. Functional connectivity (FC) was also calculated between nodes with significant local and global intrinsic brain functional alterations. The severity of anhedonia and depression was assessed with the Temporal Experience of Pleasure Scale and Hamilton Depression Rating Scale, respectively. The relationship between the change in anhedonia and depressive symptoms and brain functional alterations was determined. Increased ALFF and DC were observed in the bilateral dorsal medial prefrontal cortex (dmPFC), right dorsal lateral prefrontal cortex (dlPFC), left orbitofrontal cortex, and right orbitofrontal cortex (ROFC) after ECT. Correlational analysis between the change in anhedonia and ALFF had positive results in the dmPFC. Similarly, there was a positive correlation between the change in anhedonia and change in DC in the dmPFC, right dlPFC, ROFC, and middle frontal gyrus. Furthermore, there was a significant relationship between the change in anhedonia and altered dmPFC-dlPFC FC. These results revealed that amelioration of anhedonia may be associated with intrinsic neural activity alteration in the reward-related circuit and executive control network following ECT.

The RNA chaperone Hfq regulates expression of fimbrial-related genes and virulence of Salmonella enterica serovar Enteritidis.

Salmonella Enteritidis is an intracellular pathogen that causes enteritis and systemic disease in humans and other animals. The RNA chaperone protein Hfq mediates the binding of small noncoding RNAs to target mRNA and assists in post-transcriptional gene regulation in bacteria. In this study, we constructed an hfq deletion mutant in S. Enteritidis SE50336 and analyzed the expression of major fimbrial subunits sefA, bcfA, fimA, safA, stbA, sthA, csgA, csgD, and pegA using quantitative real-time PCR. The gene expression of sefA increased about 14-fold in the hfq mutant, as compared with its expression in the wild-type strain. The expression of fimA and pegA did not change significantly, while the expression of the other fimbrial genes was significantly down-regulated in the hfq mutant. The ability of SE50336Δhfq adhering to Caco-2 cells was also reduced as compared with wild-type adherence. The virulence of the hfq mutant was significantly reduced in a 1-day-old chicken model of S. Enteritidis disease, as determined by quantifying the lethal dose 50% of the bacterial strains. We conclude that Hfq critically contributes to S. Enteritidis virulence, likely partially affected by regulating fimbrial gene expression.