Oxygen‐redox of layer‐structured metal‐oxide cathodes has drawn great attention as an effective approach to break through the bottleneck of their capacity limit. However, reversible oxygen‐redox can ...only be obtained in the high‐voltage region (usually over 3.5 V) in current metal‐oxide cathodes. Here, we realize reversible oxygen‐redox in a wide voltage range of 1.5–4.5 V in a P2‐layered Na0.7Mg0.2Fe0.2Mn0.6□0.2O2 cathode material, where intrinsic vacancies are located in transition‐metal (TM) sites and Mg‐ions are located in Na sites. Mg‐ions in the Na layer serve as “pillars” to stabilize the layered structure during electrochemical cycling, especially in the high‐voltage region. Intrinsic vacancies in the TM layer create the local configurations of “□–O–□”, “Na–O–□” and “Mg–O–□” to trigger oxygen‐redox in the whole voltage range of charge–discharge. Time‐resolved techniques demonstrate that the P2 phase is well maintained in a wide potential window range of 1.5–4.5 V even at 10 C. It is revealed that charge compensation from Mn‐ and O‐ions contributes to the whole voltage range of 1.5–4.5 V, while the redox of Fe‐ions only contributes to the high‐voltage region of 3.0–4.5 V. The orphaned electrons in the nonbonding 2p orbitals of O that point toward TM‐vacancy sites are responsible for reversible oxygen‐redox, and Mg‐ions in Na sites suppress oxygen release effectively.
Na0.7Mg0.2Fe0.2Mn0.6□0.2O2 with native transitional metal (TM) vacancies is designed as a novel cathode material for sodium‐ion batteries. The TM vacancies lead to nonbonding O 2p orbitals in this material, pointing toward these vacancies triggering reversible whole‐voltage‐range oxygen redox during charge and discharge processes. This work provides new ideals for design of cathode materials in anionic redox chemistry.
The ongoing new coronavirus pneumonia (Corona Virus Disease 2019, COVID-19) outbreak is spreading in China, but it has not yet reached its peak. Five million people emigrated from Wuhan before ...lockdown, potentially representing a source of virus infection. Determining case distribution and its correlation with population emigration from Wuhan in the early stage of the epidemic is of great importance for early warning and for the prevention of future outbreaks.
The official case report on the COVID-19 epidemic was collected as of January 30, 2020. Time and location information on COVID-19 cases was extracted and analyzed using ArcGIS and WinBUGS software. Data on population migration from Wuhan city and Hubei province were extracted from Baidu Qianxi, and their correlation with the number of cases was analyzed.
The COVID-19 confirmed and death cases in Hubei province accounted for 59.91% (5806/9692) and 95.77% (204/213) of the total cases in China, respectively. Hot spot provinces included Sichuan and Yunnan, which are adjacent to Hubei. The time risk of Hubei province on the following day was 1.960 times that on the previous day. The number of cases in some cities was relatively low, but the time risk appeared to be continuously rising. The correlation coefficient between the provincial number of cases and emigration from Wuhan was up to 0.943. The lockdown of 17 cities in Hubei province and the implementation of nationwide control measures efficiently prevented an exponential growth in the number of cases.
The population that emigrated from Wuhan was the main infection source in other cities and provinces. Some cities with a low number of cases showed a rapid increase in case load. Owing to the upcoming Spring Festival return wave, understanding the risk trends in different regions is crucial to ensure preparedness at both the individual and organization levels and to prevent new outbreaks.
Weyl points, as a signature of 3D topological states, have been extensively studied in condensed matter systems. Recently, the physics of Weyl points has also been explored in electromagnetic ...structures such as photonic crystals and metamaterials. These structures typically have complex three-dimensional geometries, which limits the potential for exploring Weyl point physics in on-chip integrated systems. Here we show that Weyl point physics emerges in a system of two-dimensional arrays of resonators undergoing dynamic modulation of refractive index. In addition, the phase of modulation can be controlled to explore Weyl points under different symmetries. Furthermore, unlike static structures, in this system the non-trivial topology of the Weyl point manifests in terms of surface state arcs in the synthetic space that exhibit one-way frequency conversion. Our system therefore provides a versatile platform to explore and exploit Weyl point physics on chip.
The development of high-resolution magnetic resonance imaging (HR-MRI) has enabled submillimeter-level evaluation of intracranial artery plaque and luminal thrombus. We sought to investigate the ...value of HR-MRI in assessing the pathogenesis of acute intracranial artery thrombus.
We examined the presence of intracranial thrombus on three-dimensional T1-weighted HR-MRI in acute ischemic stroke patients with intracranial artery occlusion on magnetic resonance angiography. We defined two thrombus-related HR-MRI features (peri-thrombus plaque and distal residual flow beyond the thrombus) and analyzed their association with potential embolic sources.
Luminal thrombus and a shrunken artery without luminal thrombus were detected in 162 (96.4%) and 6 (3.6%) of 168 patients with intracranial artery occlusion, respectively. Among 111 patients with culprit major artery thrombus, peri-thrombus plaques were observed in 46.8% and distal residual flow beyond the thrombus in 64.0%. Patients with peri-thrombus plaque had a higher prevalence of diabetes (44.2% vs. 25.4%, p=0.037), a lower prevalence of potential sources of cardioembolism (0% vs. 16.9%, p=0.002), and a non-significantly lower prevalence of potential embolic sources from extracranial arteries (9.6% vs. 20.3%, p=0.186) than those without. Patients with distal residual flow beyond the thrombus had a lower prevalence of potential sources of cardioembolism (1.4% vs. 22.5%, p<0.001) and smaller infarct volumes (5.01.4-12.7 ml vs. 16.62.4-94.6 ml, p=0.012) than those without.
HR-MRI helps clarify the pathogenesis of acute intracranial artery thrombus. The presence of peri-thrombus plaque and distal residual flow beyond the thrombus favor the stroke mechanism of atherosclerosis rather than cardioembolism.
We report the existence of Weyl points in a class of noncentral symmetric metamaterials, which has time reversal symmetry, but does not have inversion symmetry due to chiral coupling between electric ...and magnetic fields. This class of metamaterial exhibits either type-I or type-II Weyl points depending on its nonlocal response. We also provide a physical realization of such metamaterial consisting of an array of metal wires in the shape of elliptical helices which exhibits type-II Weyl points.
Asthma is a complex disease. The heterogeneity of airway inflammation during asthma indicates there are different mechanisms involved. In order to further study the mechanisms of asthma, different ...mouse models were established to mimic corresponding subtypes of asthma in clinic. Eosinophilic asthma was established by intraperitoneal injections of ovalbumin (OVA) on day 0 and day 7, followed by inhalation of aerosolized OVA on days 14-17. Neutrophilic asthma was established by transtracheal administration of a high dose of lipopolysaccharide (LPS; 10 µg) on days 15 and 17 in combination with OVA sensitization and challenge as described previously. Mix-granulocytic asthma was established by transtracheal administration of a low dose of LPS (1 µg) on day 15, in combination with OVA sensitization and challenge as described previously. Compared with healthy controls, increased numbers of eosinophils, elevated levels of T helper (Th)2 cytokines in bronchoalveolar lavage fluid (BALF), and moderated inflammation of lung tissues was observed in eosinophilic asthma. Increased numbers of neutrophils, elevated levels of Th1 and Th17 cytokines in BALF and severe inflammation of lung tissues was observed in neutrophilic asthma. Increased numbers of both eosinophils and neutrophils, elevated levels of Th1, Th2 and Th17 cytokines in BALF and severe inflammation of lung tissues was observed in mix-granulocytic asthma. Airway hyperresponsiveness, increased bronchial mucus secretion, and elevated serum levels of immunoglobin (Ig)E and OVA-IgE were detected in all three asthma models. Dexamethasone reduced the pathogenic symptoms of the mice in eosinophilic asthma, however had no effect on neutrophilic asthma or mix-granulocytic asthma. Each model of asthma established in the present study represents corresponding subtypes of asthma in clinic.
This study explored the feasibility of using EEG gamma-band (30-49 Hz) power as an index of cue-elicited craving in METH-dependent individuals.
Twenty-nine participants dependent on methamphetamine ...(METH) and 30 healthy participants were instructed to experience a METH-related virtual reality (VR) social environment.
Individuals with METH dependence showed significantly stronger self-reported craving and higher gamma power in a VR environment than healthy individuals. In the METH group, the VR environment elicited a significant increase in gamma power compared with the resting state. The METH group then received a VR counterconditioning procedure (VRCP), which was deemed useful in suppressing cue-induced reactivity. After VRCP, participants showed significantly lower self-reported craving scores and gamma power when exposed to drug-related cues than the first time.
These findings suggest that the EEG gamma-band power may be a marker of cue-induced reactivity in patients with METH dependence.
We propose a waveguiding mechanism based on the effective gauge potential for photons. The waveguide geometry consists of core and cladding regions with the same underlying dispersion relation, but ...subject to different gauge potentials. This geometry can be realized in a dynamically modulated resonator lattice and provides a conceptually straightforward and dynamically reconfigurable mechanism for generating a one-way waveguide.
In recent years, berberine has become widely used as an effective alternative to treat dyslipidaemias; much clinical evidence has emerged. It is important to systematically and critically evaluate ...the existing evidence.
This study aims to evaluate the efficacy and safety of berberine in patients with dyslipidaemias.
A systematic review and meta-analysis of randomized clinical trials.
Five electronic databases were searched up to Apr 15, 2018 to identify randomized controlled trials (RCTs) of berberine in treatment of dyslipidaemias. The outcomes were lipid profile parameters and adverse events. Study selection, data collection, risk of bias assessment, data analyses and interpretations were conducted according to the Cochrane handbook.
Sixteen trials with total of 2147 participants were judged to be eligible and were included in the meta-analysis. The included trials were assessed to be of high clinical heterogeneity. The methodological quality of the majority of the trials was generally low in terms of random sequence generation, allocation concealment, blinding and incomplete outcome data. Thus, selection bias, performance bias, detection bias, attrition bias and confounding bias might exist. Meta-analysis showed that berberine significantly reduced levels of total cholesterol (TC) (MD = -0.47 mmol/l 95% CI -0.64, -0.31, p < 0.00001), low-density lipoprotein cholesterol (LDL-C) (MD =-0.38 mmol/l 95% CI -0.53, -0.22, p < 0.00001) and triglycerides (TG) (MD = -0.28 mmol/l 95% CI -0.46, -0.10, p = 0.002). Berberine also increased the level of high-density lipoprotein cholesterol (HDL-C) when used alone (MD = 0.08 mmol/l 95% CI 0.03, 0.12, p = 0.001). No significant differences were found between groups in terms of incidence of adverse events (RR = 0.64 95% CI 0.31, 1.30, p = 0.22). No severe adverse effects were reported in either group.
Berberine improves lipid profiles in dyslipidaemias with satisfactory safety. Nevertheless, these findings should be interpreted with caution because of the high clinical heterogeneity and high risk of bias in the included trials. Rigorous clinical trials should be carried out to provide more reliable evidence.
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