Establishing reaction networks in the 16-electron sulfur reduction reaction.

The sulfur reduction reaction (SRR) plays a central role in high-capacity lithium sulfur (Li-S) batteries. The SRR involves an intricate, 16-electron conversion process featuring multiple lithium polysulfide intermediates and reaction branches1-3. Establishing the complex reaction network is essential for rational tailoring of the SRR for improved Li-S batteries, but represents a daunting challenge4-6. Herein we systematically investigate the electrocatalytic SRR to decipher its network using the nitrogen, sulfur, dual-doped holey graphene framework as a model electrode to understand the role of electrocatalysts in acceleration of conversion kinetics. Combining cyclic voltammetry, in situ Raman spectroscopy and density functional theory calculations, we identify and directly profile the key intermediates (S8, Li2S8, Li2S6, Li2S4 and Li2S) at varying potentials and elucidate their conversion pathways. Li2S4 and Li2S6 were predominantly observed, in which Li2S4 represents the key electrochemical intermediate dictating the overall SRR kinetics. Li2S6, generated (consumed) through a comproportionation (disproportionation) reaction, does not directly participate in electrochemical reactions but significantly contributes to the polysulfide shuttling process. We found that the nitrogen, sulfur dual-doped holey graphene framework catalyst could help accelerate polysulfide conversion kinetics, leading to faster depletion of soluble lithium polysulfides at higher potential and hence mitigating the polysulfide shuttling effect and boosting output potential. These results highlight the electrocatalytic approach as a promising strategy for tackling the fundamental challenges regarding Li-S batteries.

Discovery and Development of Macrolides as Anticancer Agents.

Cancer is a life-threatening destructive disease. In the past several decades, the incidence of cancer has been dramatically increased mostly due to lifestyle changes. Chemotherapy plays an important role in the treatment of cancer, but the development of resistance against chemotherapeutic agents, the side effects, and non-specific toxicity threatens the efficiency of anticancer agents. Accordingly, it is important to develop novel anticancer drugs. Beyond the classical antibacterial activity, macrolides also demonstrated potential effects against both drug-sensitive and drug-resistant cancers through modulating diverse targets and signaling pathways, so rational design of macrolides may generate valuable therapeutic interventions for the treatment of cancers. The purpose of the present review article is to outline the current developments in macrolides with an emphasis on anticancer activity, structure-activity relationships, and mechanisms of action to lay the path for the development of novel macrolide anticancer candidates.

Outcome of multimodal MRI-guided intravenous thrombolysis in patients with stroke with unknown time of onset.

OBJECTIVE: Intravenous tissue plasminogen activator (tPA) is the standard therapy for patients with acute ischaemic stroke (AIS) within 4.5 hours of onset. Recent trials have expanded the endovascular treatment window to 24 hours. We investigated the efficacy and safety of using multimodal MRI to guide intravenous tPA treatment for patients with AIS of unknown time of onset (UTO). METHODS: Data on patients with AIS with UTO and within 4.5 hours of onset were reviewed. Data elements collected and analysed included: demographics, National Institutes of Health Stroke Scale (NIHSS) score at baseline and 2 hours, 24 hours, 7 days after thrombolysis and before discharge, the modified Rankin Scale (mRS) score at 3 months after discharge, imaging findings and any adverse event. RESULTS: Forty-two patients with UTO and 62 in control group treated within 4.5 hours of onset were treated with intravenous tPA. The NIHSS scores after thrombolysis and/or before discharge in UTO group were significantly improved compared with the baseline (p<0.05). Between the two groups, no significant differences in NIHSS score were observed (p>0.05). Utilising the non-inferiority test, to compare mRS scores (0-2) at 3 months between the two groups, the difference was 5.2% (92% CI, OR 0.196). Patients in the UTO group had mRS scores of 0-2, which were non-inferior to the control group. Their incidence of adverse events was similar. CONCLUSIONS: Utilising multimodal MRI to guide intravenous only thrombolysis for patients with AIS with UTO was safe and effective. In those patients with AIS between 6 and 24 hours of time of onset but without large arterial occlusion, intravenous thrombolysis could be considered an option.

The long-non-coding RNA NEAT1 is a novel target for Alzheimer's disease progression via miR-124/BACE1 axis.

OBJECTIVES: Long-non-coding RNAs (lncRNAs) have been involved in central nervous system recently. A number of studies have reported that lncRNA NEAT1 exerts critical roles in neurodegenerative disorder. Beta-site amyloid precursor protein cleaving enzyme 1 (BACE1) has been reported to exert function in the accumulation of amyloid-ß (Aß). Moreover, BACE1 acts as a target of miR-124 in the progression of AD. So far, the biological role and underlying mechanisms of NEAT1 and miR-124 in AD remains elusive. METHODS: The relative NEAT1 and miR-124 expression was examined by qRT-PCR in the tissues and cells line of AD. Cell apoptosis was examined by FACS. Luciferase reporter assay was performed to verify that miR-124 is a direct target of NEAT1, and BACE1 is a downstream target of miR-124. qRT-PCR and western blot analysis were also performed to determinate the BACE1 and the phosphorylation of tau protein. RESULTS: NEAT1 was notably up-regulated and miR-124 was remarkably down-regulated in AD mouse model. Knockdown of NEAT1 or overexpression of miR-124 showed the protective effects on cellular AD model induced by Aß. Moreover, miR-124 expression could be up- and down-regulated by suppression or overexpression of NEAT1, respectively. In addition, the expression of BACE1 was the potential functional target of miR-124. These findings suggested that NEAT1 might play a vital role in the development of AD by regulating miR-124/BACE1 axis. DISCUSSION: The present study showed that NEAT1 worked as a regulating factor to promote the development of AD via modulating miR-124/BACE1 axis, which might be considered as a novel target in AD treatment.

Elucidation of correlated disorder in zeolite IM-18.

Classical crystallography is based on the translational periodicity of crystals and the analysis of discrete Bragg reflections. However, it is inadequate for determining disordered structures, of which the diffuse scattering is vital to evaluate the disorder level. The correlated disorder of IM-18 presents as zigzag chains arranged in translational periodicity and the double four-ring units randomly distributed along two dimensions. Supercell models regulated by multiple probabilities were systematically built to simulate the single-crystal and powder X-ray diffraction patterns in order to ascertain the specific disorder configuration in the single-crystal or polycrystalline samples of IM-18. The presence of defects in the polycrystalline sample was proved by combining 29Si magic angle spinning (MAS) NMR and 1H-1H double quantum MAS NMR spectra, and was quantitatively explored by the simulation method. The method could also elucidate other disordered structures in polycrystalline or single-crystal samples, despite the presence of defects or multidimensional disorder.

Investigation of pyrolysis behavior of carbofuran by pyrolysis-gas chromatography-mass spectrometry.

Carbofuran is a kind of carbamate pesticide commonly used on major crops. For understanding of the composition variation versus temperature and pyrolysis mechanism, its pyrolysis behavior was simulated and investigated by pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS). The pyrolysates were directly injected for GC-MS analysis. Totally 86 components were determined based on mass spectra library matching with the aid of the correlation of boiling point (bp) and retention time. It was found that carbofuran was obviously decomposed with the temperature increase. A large number of mono aromatics and polycyclic aromatic hydrocarbons (PAHs) were formed when the temperature was higher than 750 degrees C, and the higher was the temperature, the more was the content of the corresponding aromatic hydrocarbon. Besides the aromatic hydrocarbons, there were oxygenous and/or nitrogenous compounds produced in the pyrolysis process. Furthermore, the pyrolysis mechanism of carbofuran was proposed based on the determined pyrolysates and their contents variation versus the temperature. The investigation results can provide the useful information for understanding of the thermal behavior of carbofuran and evaluation of the potential influence of the pyrolysates to living thing and the environment.