516 research outputs found
Hierarchical TiO2 spheres assisted with graphene for a high performance lithium–sulfur battery
In this study, we report hierarchical TiO2 sphere–sulfur frameworks assisted with graphene as a cathode material for high performance lithium–sulfur batteries. With this strategy, the volume expansion and aggregation of sulfur nanoparticles can be effectively mitigated, thus enabling high sulfur utilization and improving the specific capacity and cycling stability of the electrode. Modification of the TiO2–S nanocomposites with graphene can trap the polysulfides via chemisorption and increase the electronic connection among various components. The graphene-assisted TiO2–S composite electrodes exhibit high specific capacity of 660 mA h g−1 at 5C with a capacity loss of only 0.04% per cycle in the prolonged charge–discharge processes at 1C
Intracellular DNA Damage by Lysine-Acetylene Conjugates
Previously, we reported the design and properties of alkyne C-lysine conjugates, a powerful and tunable family of DNA cleaving reagents. We also reported that, upon photoactivation, these molecules are capable of inducing cancer cells death. To prove that the cell death stems from DNA cleavage by the conjugates, we investigated intracellular DNA damage induced by these molecules in LNCap cancer cells using single cell gel electrophoresis (SCGE) assays. The observation of highly efficient DNA damage confirmed that lysine acetylene conjugate is capable of cleaving the densely compacted intracellular DNA. This result provides a key mechanistic link between efficient DNA cleavage and cytotoxicity towards cancer cells for this family of light-activated anticancer agents
Hydrometeorological Applications: Severe Weather Precipitation Detection, Estimation, and Forecast
Surface modification of NiCo2Te4 nanoclusters: a highly efficient electrocatalyst for overall water-splitting in neutral solution
In this paper, we for the first time report the catalytic activity and durability of nickel cobaltite telluride (NiCo2Te4) nanocluster bifunctional catalysts can be significantly boosted by surface modification with perylene-tetracarboxylic-dianhydride for overall water-splitting in neutral solution. We reveal that tuning energy distribution of nanoclusters via a simple surface ligand can drastically increase the catalytic activity towards efficient hydrogen and oxygen evolution reaction simultaneously. A two-electrode based water electrolysis cell using this newly developed nanocluster catalyst operates at a low bias voltage of 1.55 V to achieve a current density of 10 mA·cm-2 in near-neutral pH solution for overall water-splitting. This, to the best of our knowledge, represents the most efficient mixed-transition-metal-based electrode that has so far been reported for electrochemical water splitting
GPS Scintillations and TEC Variations in Association With a Polar Cap Arc
A unique example of a polar cap arc producing clear amplitude and phase scintillations in GPS L-band signals is presented using observations from an all-sky imager and a GPS receiver and a digital ionosonde at Resolute Bay and the SuperDARN Inuvik radar. During the southward interplanetary magnetic field (IMF) condition, the polar cap arc moved quickly from the dusk-side to the midnight auroral oval at a speed of ∼700 m/s, as revealed by all-sky 557.7 and 630.0 nm images. When it intersected the raypath of GPS signals, both amplitude and phase scintillations appeared, which is very different from previous results. Moreover, the scintillations were precisely determined through power spectral analysis. We propose that the strong total electron content (TEC) enhancement (∼6 TECU) and flow shears in association with the polar cap arc under the southward IMF condition were creating the scintillations. It provides evidence for the existence of polar cap arc scintillations that may be harmful for satellite applications even through L-band signals.publishedVersio
Risk factors of amyotrophic lateral sclerosis: a global meta-summary
BackgroundThe etiology of amyotrophic lateral sclerosis (ALS) remains largely unknown. This study aimed to summarize the relationship between ALS and its genetic and non-genetic risk factors.MethodA search of relevant literature from PubMed, Embase, and Cochrane Database from inception to December 2022 was performed. Random-effects or fixed-effects models were performed by Stata MP 15.0 to pool multivariate or adjusted ratios (OR). PROSPERO registration number: CRD42022301549.Results230 eligible studies were included, of which 67 involved 22 non-genetic factors, and 163 involved genetic factors. Four aspects of non-genetic factors, including lifestyle, environmental and occupational exposures, pre-existing diseases/comorbidity and medical exposures, and others, were analyzed. Exposure to heavy metals (OR = 1.79), pesticides (OR = 1.46), solvents (OR = 1.37), previous head trauma (OR = 1.37), military service (OR = 1.29), stroke (OR = 1.26), magnetic field (OR = 1.22) and hypertension (OR = 1.04) are significant risk factors, but use of antidiabetics (OR = 0.52), high BMI (OR = 0.60 for obese and overweight vs. normal and underweight), living in urban (OR = 0.70), diabetes mellitus (OR = 0.83), and kidney disease (OR = 0.84) decrease the risk for ALS. In addition, eight common ALS-related genes were evaluated, the mutation frequencies of these genes were ranked from highest to lowest as SOD1 (2.2%), C9orf72 (2.1%), ATXN2 (1.7%), FUS (1.7%), TARDBP (0.8%), VCP (0.6%), UBQLN2(0.6%) and SQSTM1 (0.6%) in all the ALS patients.ConclusionsOur findings suggested that effective intervention for risk exposure and timely modification of lifestyle might prevent the occurrence of ALS. Genetic mutations are important risk factors for ALS and it is essential to detect genetic mutations correctly and scientifically.Systematic review registrationhttps://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=301549, identifier: CRD42022301549
Biofeedback Therapy Combined with Traditional Chinese Medicine Prescription Improves the Symptoms, Surface Myoelectricity, and Anal Canal Pressure of the Patients with Spleen Deficiency Constipation
In order to observe the clinical therapeutic effects of Yiqi Kaimi Prescription and biofeedback therapy on treating constipation with deficiency of spleen qi, the 30 cases in the control group were given oral administration of Yiqi Kaimi Prescription, in combination with anus-lifting exercise; the 30 cases in the treatment group were given biofeedback therapy on the basis of the afore mentioned methods for the control group. The TCM symptom scores and anorectal pressures before and after treatment were observed and evaluated. There were significant differences in TCM symptom scores, anorectal pressure, and clinical recovery rate before and after treatment. In the treatment group, the total recovery rate was 86.66%, while in the control group it was 50%; there were significant differences between the two groups (P<0.01). Yiqi Kaimi Prescription coupled with biofeedback therapy is clinically effective for treating constipation with deficiency of spleen qi, and thus this method is applicable for functional constipation with deficiency of spleen qi
Tuning electrochemical catalytic activity of defective 2D terrace MoSe2 heterogeneous catalyst via Co doping
This study presents successful growth of defective 2D terrace MoSe2/CoMoSe lateral heterostructures (LH), bilayer and multilayer MoSe2/CoMoSe LH, and vertical heterostructures (VH) nanolayers by doping metal Co (cobalt) element into MoSe2 atomic layers to form a CoMoSe alloy at the high temperature (~900 °C). After the successful introduction of metal Co heterogeneity in the MoSe2 thin layers, more active sites can be created to enhance hydrogen evolution reaction (HER) activities combining with metal Co catalysis, through the mechanisms including (1) atomic arrangement distortion in CoMoSe alloy nanolayers, (2) atomic level coarsening in LH interfaces and terrace edge layer architecture in VH, (3) formation of defective 2D terrace MoSe2 nanolayers heterogeneous catalyst via metal Co doping. The HER investigations indicated that the obtained products with LH and VH exhibited an improved HER activity in comparison with those from the pristine 2D MoSe2 electrocatalyst and LH type MoSe2/CoMoSe. The present work shows a facile yet reliable route to introduce metal ions into ultrathin 2D transition metal dichalcogenides (TMDCS) and produce defective 2D alloy atomic layers for exposing active sites, and thus eventually improve their electrocatalytic performance
Phosphor coated NiO-based planar inverted organometallic halide perovskite solar cells with enhanced efficiency and stability
This work investigates non-rare-earth phosphor (Sr4Al14O25:Mn4+, 0.5%Mg) with intensively red luminescence as a luminescent down-shifting layer for perovskite solar cells. The power conversion efficiency of the fabricated device with a structure of NiO/CH3NH3PbI3/[6,6]-phenyl C61-butyric acid methyl ester/Au coated with phosphor layer shows a 10% increase as compared with that of the control devices. Importantly, the phosphor layer coating can realize UV-protection as well as waterproof capability, achieving a reduced moisture-degradation of CH3NH3PbI3 perovskite upon applying an UV irradiation. Therefore, perovskite devices using this luminescent coating show a combined enhancement in both UV down-shifting conversion and long term stability. This can be expanded as a promising encapsulation technique in the perovskite solar cell community
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