ABSTRACT
The cathodic product Li2CO3, due to its high decomposition potential, has hindered the practical application of rechargeable Li-CO2/O2 batteries. To overcome this bottleneck, a Pt/FeNC cathodic catalyst is fabricated by dispersing Pt nanoparticles (NPs) with a uniform size of 2.4 nm and 8.3 wt % loading amount into a porous microcube FeNC support for high-performance rechargeable Li-CO2/O2 batteries. The FeNC matrix is composed of numerous two-dimensional (2D) carbon nanosheets, which is derived from an Fe-doping zinc metal-organic framework (Zn-MOF). Importantly, using Pt/FeNC as the cathodic catalyst, the Li-CO2/O2 (VCO2/VO2 = 4:1) battery displays the lowest overpotential of 0.54 V and a long-term stability of 142 cycles, which is superior to batteries with FeNC (1.67 V, 47 cycles) and NC (1.87 V, 23 cycles) catalysts. The FeNC matrix and Pt NPs can exert a synergetic effect to decrease the decomposition potential of Li2CO3 and thus enhance the battery performance. In situ Fourier transform infrared (FTIR) spectroscopy further confirms that Li2CO3 can be completely decomposed under a low potential of 3.3 V using the Pt/FeNC catalyst. Impressively, Li2CO3 exhibits a film structure on the surface of the Pt/FeNC catalysts by scanning electron microscopy (SEM), and its size can be limited by the confined space between the carbon sheets in Pt/FeNC, which enlarges the better contacting interface. In addition, density functional theory (DFT) calculations reveal that the Pt and FeNC catalysts show a higher adsorption energy for Li2CO3 and Li2CO4 intermediates compared to the NC catalyst, and the possible discharge pathways are deeply investigated. The synergetic effect between the FeNC support and Pt active sites makes the Li-CO2/O2 battery achieve optimal performance.
ABSTRACT
The construction of an efficient oxygen reduction reaction and oxygen evolution reaction (ORR/OER) bifunctional electrocatalyst is of great significance but still remains a giant challenge for high-performance metal-air batteries. In this study, uniform FeS/Fe3C nanoparticles embedded in a porous N,S-dual doped carbon honeycomb-like composite (abbr. FeS/Fe3C@NS-C-900) have been conveniently fabricated by pyrolysis of a single-crystal Fe-MOF, which has a low potential gap ΔE of ca. 0.72 V, a competitive power density of 90.9 mW/cm2, a specific capacity as high as 750 mAh/gZn, and excellent cycling stabilities over 865 h (1730 cycles) at 2 mA/cm2 when applied as a cathode material for rechargeable zinc-air batteries. In addition, the two series-linked Zn-air batteries successfully powered a 2.4 V LED light as a real power source. The efficient ORR/OER bifunctional electrocatalytic activity and long-term durability of the obtained composite might be attributed to the characteristic honeycomb-like porous structure with sufficient accessible active sites, the synergistic effect of FeS and Fe3C, and the N,S codoped porous carbon, which provides a promising application potential for portable electronic Zn-air battery related devices.
ABSTRACT
Dinuclear metal clusters as metalloenzymes execute efficient catalytic activities in biological systems. Enlightened by this, a dinuclear {CoII 2} cluster was selected to survey its ORR (Oxygen Reduction Reaction) catalytic activities. The crystalline {CoII 2} possesses defined structure and potential catalytic active centers of {CoN4O2} sites, which was identified by X-ray single crystal diffraction, Raman and XPS. The appropriate supramolecular porosity combining abundant pyridinic-N and triazole-N sites of {CoII 2} catalyst synergistically benefit the ORR performance. As a result, this non-noble metal catalyst presents a nice ORR electrocatalytic activity and abides by a nearly 4-electron reduction pathway. Thus, this unpyrolyzed crystalline catalyst clearly provide precise active sites and the whole defined structural information, which can help researcher to design and fabricate efficient ORR catalysts to improve their activities. Considering the visible crystal structure, a single cobalt center-mediated catalytic mechanism was also proposed to elucidate the ORR process.
ABSTRACT
In the present study, we determined the protective role of lutein against Aß 25-35 peptide-induced oxidative stress and apoptosis in bEND.3 cells. Cell viability was determined through MTT assay. Reactive oxygen species, lipid peroxides, and antioxidant enzyme activities were evaluated to analyze the oxidative stress status. NF-κB and Nrf-2 downstream target protein expressions were determined through western blot. Apoptosis was analyzed through caspase activities and subG1 accumulation. The results showed that Aß 25-35 significantly increased (p < 0.001) oxidative stress biomarkers. Aß 25-35 significantly up-regulated NF-κB nuclear expression and down-regulated Nrf-2 levels and HO-1 and, NQO-1 expressions. Aß 25-35 induced apoptosis through decreasing mitochondrial membrane potential and increasing caspase 9 and 3 activities. Lutein pre-treatment significantly (p < 0.001) improved cell viability and decreased ROS levels (p < 0.001) and lipid peroxidation (p < 0.01). Lutein prevented Aß 25-35-induced NF-κB nuclear expressions and up-regulated Nrf-2 expressions. Further, lutein also improved mitochondrial membrane potential and down-regulated caspase activities and subG1 accumulation. The present study shows the protective role of lutein against Aß 25-35-induced toxicity by modulating Nrf-2 and NF-κB expressions in cerebrovascular endothelial cells.
Subject(s)
Amyloid beta-Peptides/toxicity , Endothelial Cells/pathology , Lutein/pharmacology , NF-E2-Related Factor 2/metabolism , NF-kappa B/metabolism , Neuroprotective Agents/pharmacology , Oxidative Stress/drug effects , Apoptosis/drug effects , Cell Nucleus/drug effects , Cell Nucleus/metabolism , Endothelial Cells/drug effects , Endothelial Cells/metabolism , Heme Oxygenase-1/metabolism , Humans , Models, Biological , NAD(P)H Dehydrogenase (Quinone)/metabolism , Protein Transport/drug effects , Up-Regulation/drug effectsABSTRACT
BACKGROUND: Chemotherapy is one of the major means for control of malignancies, with cisplatin (CDDP) as one of the main agents, widely used for the treatment of various malignant solid tumors. However, prevention of hepatotoxicity from cisplatin is one of the urgent issues in cancer chemotherapy. In this study, we aimed to investigate the effects of pu-erh tea on hepatotoxicity through body weight and tissue antioxidant parameters like, liver coefficient, serum alanine aminotransferase (ALT), serum aspartate aminotransferase (AST), superoxide dismutase (SOD), glutathione peroxidase (GSH-PX), malondialdehyde(MDA) and glutathione (GSH) levels, and light microscopic evaluation by histological findings. MATERIALS AND METHODS: The rats were randomly divided into five groups: Control (n=10), cisplatin (3 mg/kg p.i., n=10), cisplatin+pu-erh (0.32 g/kg/day i.g., n=10), cisplatin+pu-erh (0.8 g/kg/day i.g., n=10) and cisplatin+pu-erh (1.6 g/kg/day i.g., n=10). Pu-erh tea powder was administrated for 31 consecutive days. The rats were sacrificed at the end on the second day after a single dose of cisplatin treatment for measuring indices. RESULTS: Pu-erh tea powder exhibited a protective effect by decreasing MDA and GSH and increasing the SOD and GSH-PX levels and GSH-PX/MDA ratio in comparison with the control group. Besides, pu-erh tea was also able to alleviate the pathological damage to some extent. CONCLUSION: Pu-erh tea powder is protective against cisplatin-induced liver oxidative damages, especially at the medium dosage (0.8 g/kg/d).
Subject(s)
Antioxidants/pharmacology , Camellia sinensis , Chemical and Drug Induced Liver Injury/prevention & control , Cisplatin/adverse effects , Liver/drug effects , Oxidative Stress/drug effects , Plant Preparations/pharmacology , Alanine Transaminase/drug effects , Alanine Transaminase/metabolism , Animals , Aspartate Aminotransferases/drug effects , Aspartate Aminotransferases/metabolism , Chemical and Drug Induced Liver Injury/etiology , Glutathione/drug effects , Glutathione/metabolism , Glutathione Peroxidase/drug effects , Glutathione Peroxidase/metabolism , Liver/metabolism , Liver/pathology , Male , Malondialdehyde/metabolism , Phytotherapy , Rats , Rats, Wistar , Superoxide Dismutase/drug effects , Superoxide Dismutase/metabolism , TeaABSTRACT
OBJECTIVE: To study clinical effects of plaster combined with splint for the treatment of Gartland type 1I humeral fractures. METHODS: From March 2002 to May 2006, 24 children with humeral supracondylar fractures of Gartland type ill were reviewed. Among the patients, 14 patients were male and 10 patients were female, ranging in age from 4 to 12 years, averaged 6.6 years. Ten patients had injuries in the left and other 14 patients had injuries in the right limb. Firstly, the patients were treated with manipulative reduction to maintain the length of humerus without emphasis on anatomic reduction. Then, the patients were treated with external fixation using plaster for 5 to 7 days, and secondary manipulative reduction after swelling disappeared. Lastly, the patients were treated with external fixation using splint for 4 to 5 weeks until fracture union. RESULTS: All the patients were followed up, and the duration ranged from 5 months to 2 years, with an average of 1.2 years. All the patients had no complications such as neurovascular injury, myositis ossificans, forearm compartment syndrome and Volkmann contracture. According to ZHU Xiao-ting evaluation criteria for humeral supracondylar fractures in children, 12 patients got an excellent result, 8 good, 3 poor and 1 bad. CONCLUSION: Treatment of child humeral supracondylar fractures with plaster and splint has several advantages such as avoiding serious soft tissue injuries around fractures due to many times reduction, fracture dynamic correction to obtain satisfactory reduction, reducing complications, obtaining good reduction, and restoring elbow function in a relatively short period of time.
Subject(s)
Casts, Surgical , Humeral Fractures/surgery , Splints , Child , Child, Preschool , Female , Humans , Humeral Fractures/diagnostic imaging , Male , RadiographyABSTRACT
In the title compound, [FePt(C(5)H(5))(C(24)H(19)NP)Cl(2)]·0.5CH(2)Cl(2), the Pt(II) atom adopts a distorted square-planar geometry defined by one P atom and one N atom from the bidentate [2-(diphenyl-phosphino)phenyl-imino-meth-yl]ferro-cene ligand and two Cl atoms. Two disordered dichloro-methane solvent mol-ecules are each 0.25-occupied on a twofold rotation axis.
ABSTRACT
Polysaccharide sulfate (PSS) is a new type of antiatherosclerotic medicine for its effects of anticoagulation, anti-thrombosis and modulation of dyslipidemia. However, it is still uncertain whether PSS could modulate the diabetic dyslipidemia or not. Here, the rat model of diabetic dyslipidemia was developed and the effects of PSS on glucose and lipid levels were investigated in this animal model. Wistar rats were iv injected with streptozotocin 20 mg x kg(-1) after feeding with high fat diet for one and a half month. Then, rats received orally PSS (30, 90, and 180 mg x kg(-1)) for 1 month. After oral treatment with PSS (90 and 180 mg x kg(-1)) for 1 month, the levels of triglyceride (TG), total cholesterol (TC), low density lipoprotein-cholesterol (LDL-C) were significantly reduced and the level of high density lipoprotein-cholesterol (HDL-C) increased, compared with diabetic control rats. Moreover, PSS (30, 90, and 180 mg x kg(-1)) had a tendency to reduce glucose and insulin levels, and significantly increased insulin sensitivity index. Our results suggest that PSS could improve insulin sensitivity and relieve dyslipidemia in diabetic dyslipidemic rats.
Subject(s)
Diabetes Mellitus, Experimental/blood , Dyslipidemias/blood , Hypolipidemic Agents/pharmacology , Insulin Resistance , Polysaccharides/pharmacology , Administration, Oral , Animals , Blood Glucose/metabolism , Cholesterol, HDL/blood , Cholesterol, LDL/blood , Diabetes Mellitus, Experimental/chemically induced , Diabetes Mellitus, Experimental/complications , Dyslipidemias/etiology , Hypolipidemic Agents/administration & dosage , Insulin/blood , Male , Polysaccharides/administration & dosage , Random Allocation , Rats , Rats, Wistar , Streptozocin , Sulfates/administration & dosage , Sulfates/pharmacology , Triglycerides/bloodABSTRACT
OBJECTIVE: To study the effect of methylprednisolone (MP) and cyclophosphamide (CPA) intermittent intravenous pulse therapy and the clinical prognosis in children with severe juvenile onset systemic lupus erythematosus (JOSLE). METHODS: Thirty patients with JOSLE, diagnosed by clinical, laboratory or renal histological examinations, were enrolled in this study. Of the 30 patients, 27 were females and 3 were males, the mean age was (12 +/- 3) years, and 20 of the 22 patients who had undergone initial therapy had LN, and the clinical courses before being involved in the study were 3 to 12 months in nine patients. Twenty-three of the 30 patients had clinical manifestations of renal damages, of whom 4 patients were proven by initial renal biopsy to have WHO type IV, 2 had type II,1 had type V and 1 had type III, and 7 patients had one or more manifestations of central nervous system, including chorea, seizures, cerebrovascular accident (CVA) and organic brain syndrome (OBS), simultaneously, 9 patients had nervous system symptoms without the clinical manifestations of renal damages, 3 patients had lupus crisis, 7 patients did not have any manifestations of renal or neurological damages. According to the protocol of the therapy, the patients were divided into 3 groups: group A (n = 18) patients were treated with MP plus CPA intermittent intravenous pulse for children with lupus nephritis, and with or without neuropsychiatric lupus erythematosus (NPLE), group B (n = 7) with pulsed doses of MP, followed by prednisone and tripterygium wilfordii hook f(T(whf)) for patients without renal or central nerves system damage, and group C (n = 5) with prednisone alone for patients with LN determined by clinical and laboratory features. The effects of those regimes and the clinical prognosis were observed. RESULTS: On short-term follow-up, the SLEDAI-2K (by weight of the renal damage) showed significant difference between group A and group B, but there was no significant difference at the 9th months of the therapy. The long-term follow-up lasted in average for (37.2 +/- 24.8) months. Nineteen patients were followed up for more than 18 months. At the end of follow-up, the mean age was 14 to 19 years. There was no difference on the effect of both group A and group B, and no frequent infections were seen, ANAs were negative and SLEDAI-2K = 0-point in two patients of each group 12 months after discontinuation of the therapy. Four patients in group C died within 18 months. CONCLUSION: The immunosuppressive regimen MP + CPA in patients with severe JOSLE and MP + prednisone + T(whf) in patients without major organs damage were superior to the regimen of prednisone alone.