The efficient separation of the orbital angular momentum (OAM) is essential to both the classical and quantum applications with twisted photons. Here we devise and demonstrate experimentally an ...efficient method of mimicking the Faraday rotation to sort the OAM based on the OAM-to-polarization coupling effect induced by a modified Mach-Zehnder interferometer. Our device is capable of sorting the OAM of positive and negative numbers, as well as their mixtures. Furthermore, we report the first experimental demonstration to sort optical vortices of noninteger charges. The possibility of working at the photon-count level is also shown using an electron-multiplying CCD camera. Our scheme holds promise for quantum information applications with single-photon entanglement and for high-capacity communication systems with polarization and OAM multiplexing.
•HRW attenuates learning and memory impairments in a rat model of VD.•HRW attenuates the neuronal apoptosis and autophagy levels in VD rats.•FoxO1-mediated autophagy is partially involved in the ...protective effects of HRW in VD rats.•Excessive autophagy and apoptosis are both activated 4 weeks after bilateral occlusion of the common carotid artery surgery in rats.
Vascular dementia (VD) is a heterogeneous group of brain disorders in which cognitive impairment is attributed to cerebrovascular pathologies. Autophagy, a self-cannibalization mechanism, has been demonstrated to be involved in VD progression. Molecular hydrogen is known for its powerful anti-oxidative, anti-apoptotic, and anti-inflammatory activities, and it is also involved in autophagy. However, the effects of hydrogen on VD remain unclear. The current study found that hydrogen-rich water (HRW) significantly alleviated spatial learning and memory impairments. Similar to donepezil treatment, HRW also inhibited neuron loss and shrinkage in the hippocampal CA1 region. In addition, we found that HRW significantly increased the Bcl-2/Bax expression ratio and decreased cleaved caspase-3 expression levels in the hippocampus of VD rats. Moreover, electron microscopy revealed that HRW decreased the number of autophagosomes. We also observed that HRW reduced the increased ratio of LC3-II/I and Beclin 1 expression and saliently upregulated p62 expression. Furthermore, FoxO1 (a major mediator of autophagy regulation) and Atg7 levels were apparently decreased in the hippocampus of HRW-treated bilateral common carotid artery occlusion (2VO) rats. Taken together, these data show that molecular hydrogen exerts beneficial effects on cognitive impairment induced by chronic cerebral hypoperfusion. FoxO1-mediated autophagy plays an important role in the neuroprotective effects of hydrogen in a rat model of VD. Furthermore, the present findings highlight that HRW should be further investigated as a new therapeutic strategy for VD treatment in the future.
Porcine epidemic diarrhea coronavirus (PEDV) has significantly damaged America's pork industry. Here we investigate the receptor usage and cell entry of PEDV. PEDV recognizes protein receptor ...aminopeptidase N from pig and human and sugar coreceptor N-acetylneuraminic acid. Moreover, PEDV infects cells from pig, human, monkey, and bat. These results support the idea of bats as an evolutionary origin for PEDV, implicate PEDV as a potential threat to other species, and suggest antiviral strategies to control its spread.
To address the inert behavior of cognitive users who do not sense to increase their throughput in the collaborative spectrum sensing process, a spectrum sensing model with a contribution reward and ...punishment mechanism is proposed to increase the motivation of spectrum sensing. The whole spectrum sensing process is normalized to the number of transmitted bits, and the energy consumption in the sensing phase is considered comprehensively and a reward and punishment function with a reward and punishment strength of 0.25 is introduced in the transmission phase to create an evolutionary game model for spectrum sensing, further select an evolutionarily stable strategy, and use a distributed algorithm to deal with the convergence problem for a given initial participation rate. The simulation results show that the stability of Dual-User cooperative spectrum sensing is the game strategy obtained by the fixed small penalty factor (perception, perception), and the game strategy obtained by the fixed large penalty factor (perception, nonperception) and (nonperception, perception). The superiority of the present reward mechanism is verified in the multi-user case, which can significantly improve the spectrum-aware participation rate and increase spectrum-aware motivation.
Natural biomolecules have been used extensively as chiral scaffolds that bind/surround metal complexes to achieve stereoselectivity in catalytic reactions. ATP is ubiquitously found in nature as an ...energy-storing molecule and can complex diverse metal cations. However, in biotic reactions ATP-metal complexes are thought to function mostly as co-substrates undergoing phosphoanhydride bond cleavage reactions rather than participating in catalytic mechanisms. Here, we report that a specific Cu(II)-ATP complex (Cu
·ATP) efficiently catalyses Diels-Alder reactions with high reactivity and enantioselectivity. We investigate the substrates and stereoselectivity of the reaction, characterise the catalyst by a range of physicochemical experiments and propose the reaction mechanism based on density functional theory (DFT) calculations. It is found that three key residues (N7, β-phosphate and γ-phosphate) in ATP are important for the efficient catalytic activity and stereocontrol via complexation of the Cu(II) ion. In addition to the potential technological uses, these findings could have general implications for the chemical selection of complex mixtures in prebiotic scenarios.
Although accumulating evidence has linked mesenchymal stem cells (MSCs) with tumor growth, the underlying mechanisms are poorly understood. Here, we demonstrated for the first time that human ...umbilical cord MSCs (hUCMSCs) dramatically increased the growth of lung adenocarcinoma (LUAD) cancer cells in a xenograft tumor model. Then, we observed that hUCMSC-derived extracellular vesicles (hUCMSC-EVs) contribute to the hUCMSC-promoted LUAD cell growth through a direct effect on LUAD cells. Furthermore, we showed that hUCMSC-EV-mediated LUAD growth is associated with increased proliferation and decreased apoptosis in LUAD cells, concomitant with reduced PTEN expression mediated by the hUCMSC-EV-transmitted miR-410. Our findings provide novel insights into the intercellular communications between cancer cells and MSCs through MSC-EV-miRNA and suggest that modification of hUCMSC-EVs might be an attractive therapeutic option for the clinical application of hUCMSC-EVs that would reduce unwanted side effects.
•Bifurcation and stability is simulated in two kinds of stochastic model.•In the bistability region, the additive disturbance could induce a transition.•Multiplicative noise could reduce the bistable ...region, even make it vanish.•Both nutrient loading and noise intensity affect multiplicative stochastic ecosystem.
In the reality, the lake system will be disturbed by stochastic factors including the external and internal factors. By adding the additive noise and the multiplicative noise to the right-hand sides of the model equation, the additive stochastic model and the multiplicative stochastic model are established respectively in order to reduce model errors induced by the absence of some physical processes. For both the two kinds of stochastic ecosystems, the authors studied the bifurcation characteristics with the FPK equation and the Lyapunov exponent method based on the Stratonovich–Khasminiskii stochastic average principle. Results show that, for the additive stochastic model, when control parameter (i.e., nutrient loading rate) falls into the interval 0.388644, 0.66003825, there exists bistability for the ecosystem and the additive noise intensities cannot make the bifurcation point drift. In the region of the bistability, the external stochastic disturbance which is one of the main triggers causing the lake eutrophication, may make the ecosystem unstable and induce a transition. When control parameter (nutrient loading rate) falls into the interval (0, 0.388644) and (0.66003825, 1.0), there only exists a stable equilibrium state and the additive noise intensity could not change it. For the multiplicative stochastic model, there exists more complex bifurcation performance and the multiplicative ecosystem will be broken by the multiplicative noise. Also, the multiplicative noise could reduce the extent of the bistable region, ultimately, the bistable region vanishes for sufficiently large noise. What's more, both the nutrient loading rate and the multiplicative noise will make the ecosystem have a regime shift. On the other hand, for the two kinds of stochastic ecosystems, the authors also discussed the evolution of the ecological variable in detail by using the Four-stage Runge–Kutta method of strong order γ=1.5. The numerical method was found to be capable of effectively explaining the regime shift theory and agreed with the realistic analyze. These conclusions also confirms the two paths for the system to move from one stable state to another proposed by Beisner et al. 3, which may help understand the occurrence mechanism related to the lake eutrophication from the view point of the stochastic model and mathematical analysis.
The potential protective effects and mechanisms of edaravone have not been well elucidated in vascular dementia (VaD) induced by chronic cerebral hypoperfusion (CCH). The aim of this study was to ...investigate whether edaravone could improve cognitive damage in rats induced by CCH, and whether the effects of edaravone were associated with ERK/Nrf2/HO-1 signaling pathway.
CCH was induced by bilateral common carotid arteries occlusion (BCCAO). Sprague-Dawley (SD) rats were randomly divided into four groups: sham (sham-operated) group, vehicle (BCCAO + normal saline) group, edaravone3.0 group and edaravone6.0 group. The edaravone3.0 and edaravone6.0 group rats were provided 3.0 mg/kg and 6.0 mg/kg of edaravone, respectively, intraperitoneal (i.p.) injection twice daily following the first day after BCCAO. In this experiment, the spatial learning and memory were assessed using the Morris water maze. The malondialdehyde (MDA) contents and superoxide dismutase (SOD) activities in the hippocampus were measured biochemically. And, the levels of total ERK1/2 (t-ERK1/2), Phospho-ERK1/2 (p-ERK1/2), total Nrf2 (t-Nrf2), nuclear Nrf2 (n-Nrf2), and HO-1 were assessed by western blot.
The results showed that the treatment with edaravone significantly improved CCH-induced cognitive damage, and boosted endogenous antioxidants SOD activity and HO-1 level, decreased MDA contents in the hippocampus by activating Nrf2 signaling pathway which was related to ERK1/2. We also found that the neuronal morphology of the hippocampal CA1 area significantly improved and the number of Nrf2 positive cells markedly increased in the edaravone treatment groups.
Our results demonstrated a neuroprotective effect of edaravone on hippocampus against oxidative stress and cognitive deficit induced by CCH. The mechanism may be related to the enhancement of antioxidant defense system by activating ERK/Nrf2/HO-1 signaling pathway.
Medical data have unique specificity and professionalism, requiring substantial domain expertise for their annotation. Precise data annotation is essential for anomaly-detection tasks, making the ...training process complex. Domain generalization (DG) is an important approach to enhancing medical image anomaly detection (AD). This paper introduces a novel multimodal anomaly-detection framework called MedicalCLIP. MedicalCLIP utilizes multimodal data in anomaly-detection tasks and establishes irregular constraints within modalities for images and text. The key to MedicalCLIP lies in learning intramodal detailed representations, which are combined with text semantic-guided cross-modal contrastive learning, allowing the model to focus on semantic information while capturing more detailed information, thus achieving more fine-grained anomaly detection. MedicalCLIP relies on GPT prompts to generate text, reducing the demand for professional descriptions of medical data. Text construction for medical data helps to improve the generalization ability of multimodal models for anomaly-detection tasks. Additionally, during the text-image contrast-enhancement process, the model's ability to select and extract information from image data is improved. Through hierarchical contrastive loss, fine-grained representations are achieved in the image-representation process. MedicalCLIP has been validated on various medical datasets, showing commendable domain generalization performance in medical-data anomaly detection. Improvements were observed in both anomaly classification and segmentation metrics. In the anomaly classification (AC) task involving brain data, the method demonstrated a 2.81 enhancement in performance over the best existing approach.
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