In this paper,we consider a class of third-order nonlinear delay dynamic equations.First,we establish a Kiguradze-type lemma and some useful estimates.Second,we give a sufficient and necessary condition for the existe...In this paper,we consider a class of third-order nonlinear delay dynamic equations.First,we establish a Kiguradze-type lemma and some useful estimates.Second,we give a sufficient and necessary condition for the existence of eventually positive solutions having upper bounds and tending to zero.Third,we obtain new oscillation criteria by employing the Potzsche chain rule.Then,using the generalized Riccati transformation technique and averaging method,we establish the Philos-type oscillation criteria.Surprisingly,the integral value of the Philos-type oscillation criteria,which guarantees that all unbounded solutions oscillate,is greater than θ_(4)(t_(1),T).The results of Theorem 3.5 and Remark 3.6 are novel.Finally,we offer four examples to illustrate our results.展开更多
Dear Editor,Physical exercise has been shown to be associated with reduced cancer incidence and cancer-associated mortality[1,2],but the underlying mechanisms are obscure.Immunometabolic regulation has emerged as one ...Dear Editor,Physical exercise has been shown to be associated with reduced cancer incidence and cancer-associated mortality[1,2],but the underlying mechanisms are obscure.Immunometabolic regulation has emerged as one of the most prominent mechanisms explaining the effects of exercise on cancer[1,2].Physical exercise primarily lowers blood cholesterol and triglycerides,and protects against cardiovascular diseases[3].However,whether physical exercise can modulate cholesterol metabolism in tumor cells is currently unknown.展开更多
The alkaline hydrogen evolution reaction(HER) on Pt-based catalysts is largely limited by the slow water dissociation kinetics. Pt-based single atom alloy catalysts(SAAC) with water dissociation sites have been demons...The alkaline hydrogen evolution reaction(HER) on Pt-based catalysts is largely limited by the slow water dissociation kinetics. Pt-based single atom alloy catalysts(SAAC) with water dissociation sites have been demonstrated as excellent alkaline HER catalysts. However, the regulation of their activity and stability at the atomic scale is still a great challenge. Herein, the kinetic and stability issues are successfully resolved via engineering the electronic structure of Pt-Co SAAC by Au-induced tensile strain. The atomic dispersion of Co into the Pt shell was confirmed by extended X-ray absorption fine structure and the electronic structure and catalytic HER performance was modulated by the tensile strain induced by the Pt shell thickness. An inverse volcano-type relation between HER activity and surface strain was found.Density functional theory(DFT) calculations reveal that the Au-induced tensile strain on Pt-Co shell can not only boost the adsorption and dissociation kinetics of water at Co site by upshifting the dband and promoting the electron transfer, but also downshift the d-band center of Pt in Pt-Co shell, leading to optimized H* adsorption/desorption. The champion catalyst provides an overpotential of only 14 m V at the current density of 10 mA cm^(-2). This work not only provides an effective strategy for the construction of single-atom alloy electrocatalysts for high performance toward alkaline HER but also sheds light on the understanding of the reaction mechanism at the atomic level.展开更多
The effect of promoter Ce on the catalytic performance of Ni/Al2O3 catalyst for autothermal reforming of methane to hydrogen was investigated. The catalysts were characterized by X-ray diffraction （XRD）, temperature...The effect of promoter Ce on the catalytic performance of Ni/Al2O3 catalyst for autothermal reforming of methane to hydrogen was investigated. The catalysts were characterized by X-ray diffraction （XRD）, temperature-programmed reduction （TPR）, and X-ray photoelectron spectroscopy （XPS）. The results indicated that the catalytic performance of the catalysts was improved with the addition of Ce. Ni/Ce30Al70Oδ showed the highest CH4 conversion in operation temperatures ranging from 650 ℃ to 850 ℃. At the same time, the decrease in H2/CO ratio with increasing reaction temperature was consistent with the fact that water-gas shift reaction was thermodynamically unfavorable at higher temperatures. The XRD result indicated that adding Ce to Ni/Al2O3 catalyst prevented the formation of NiAl2O4 and facilitated the formation of NiO. The formation of NiO increased the number of active sites, resulting in higher activity. Comparing the TPR profiles of Ni/Ce30Al70Oδ with Ni/Al2O3, it could be clearly observed that with the addition of Ce, the total reduction peak areas in the middle and low temperatures increased. It was most probably that the addition of Ce inhibited the stronger interaction between Ni and Al2O3 to form the phase of NiAl2O4, and favored the formation of the strong interaction between NiO species and CeO2. Therefore, the addition of Ce to the Ni/Al2O3 catalyst increased the active surface that promoted the activity of the catalyst.展开更多
Ni catalysts supported on Al2O3, ZrO2-Al2O3, CeO2-Al2O3 and ZrO2-CeO2-Al2O3 were prepared by coprecipitation method, and their catalytic performances for autothermal reforming of methane to hydrogen were investigated....Ni catalysts supported on Al2O3, ZrO2-Al2O3, CeO2-Al2O3 and ZrO2-CeO2-Al2O3 were prepared by coprecipitation method, and their catalytic performances for autothermal reforming of methane to hydrogen were investigated. The Ni-supported catalysts were characterized by XRD, TPR and XPS. The relationship between the structures and catalytic activities of the catalysts was discussed. The results showed that the catalytic activity and stability of the Ni/ZrO2-CeO2-Al2O3 catalyst was better than those of other catalysts with the highest CH4 conversion, H2/CO and H2/COx ratio at 750 ℃. The catalyst showed a little deactivation along the reaction time during its 72 h on stream with the mean deactivation rate of 0.08%/h. The catalytic performance of the Ni/ZrO2-CeO2-Al2O3 catalyst was also affected by reaction temperature, no2 ： nCH4 molar ratio and nH2O ： nCH4 molar ratio. TPR, XRD and XPS measurements indicated that the formation of ZrO2-CeO2 solid solution could improve the dispersion of NiO, and inhibit the formation of NiAl2O3, and thus significantly promoted the catalytic activity of the Ni/ZrO2-CeO2-Al2O3 catalyst.展开更多
A spectrophotometric method for the determination of ruthenium(III) is described, based on its catalytic effect on the oxidation reaction of dimethyl yellow (DMY) with potassium bromate in an acid solution medium and ...A spectrophotometric method for the determination of ruthenium(III) is described, based on its catalytic effect on the oxidation reaction of dimethyl yellow (DMY) with potassium bromate in an acid solution medium and in the presence of an OP emulsifier (p-iso-octyl phenoxy polyethoxy ethanol) at 100 °C. This reaction was followed spectrophotometrically by measuring the decrease in the absorbance at 530 nm of the catalytic reaction of DMY. The calibration curve for the recommended method was linear in the concentration range over 0.0–1.0 μg/L and the detection limit of the method for Ru(III) was 0.01 μg/L. The method is highly sensitive, selective and very stable and has been successfully applied for the determination of trace amounts of ruthenium in some ores and metallurgy products with the relative standard deviations (RSD) over 1.6%–2.8% and a recovery over 98.7%–104.0%.展开更多
The high-glucose tolerance of yeast is the main factor determining the efficiency of high-density alcohol fermentation.Zygosaccharomyces mellis LGL-1 isolated from honey could survive under 700 g/L high-glucose stress...The high-glucose tolerance of yeast is the main factor determining the efficiency of high-density alcohol fermentation.Zygosaccharomyces mellis LGL-1 isolated from honey could survive under 700 g/L high-glucose stress and its tolerant characteristics were identified in our previous study.This study was performed to explore and clarify the high-glucose tolerance mechanism of Z.mellis LGL-1.Comparative transcriptomic analysis was used to analyze the genes with differential expression in Z.mellis under high-glucose conditions of 300,500 and 700 g/L.With 300 g/L samples as reference,there were 937 and 2380 differentially expressed genes(DEGs)in the 500 and 700 g/L samples,respectively.Meanwhile,there was 825 significant DEGs in the 700 g/L samples compared with that of the 500 g/L samples.The result revealed that transcriptional changes in multiple metabolic pathways occur in response to high-glucose stress.q-RT PCR analysis further confirmed that several stress response pathways,such as the high osmolarity glycerol mitogen-activated protein kinase(HOG-MAPK)signal transduction pathway,trehalose synthesis pathway and oxidative stress response are closely related to high-glucose tolerance in Z.mellis.This study clarifies mechanisms of Z.mellis in response to high-glucose osmotic stress,providing theoretical basis for the process control of high-density alcohol fermentation.展开更多
Transition metal selenides have been widely studied as anode materials of sodium ion batteries(SIBs),however,the investigation of solid-electrolyte-interface(SEI)on these materials,which is critical to the electrochem...Transition metal selenides have been widely studied as anode materials of sodium ion batteries(SIBs),however,the investigation of solid-electrolyte-interface(SEI)on these materials,which is critical to the electrochemical performance of SIBs,remains at its infancy.Here in this paper,ZnSe@C nanoparticles were prepared from ZIF-8 and the SEI layers on these electrodes with and without reduced graphene oxide(rGO)layers were examined in details by X-ray photoelectron spectroscopies at varied charged/discharged states.It is observed that fast and complicated electrolyte decomposition reactions on ZnSe@C leads to quite thick SEI film and intercalation of solvated sodium ions through such thick SEI film results in slow ion diffusion kinetics and unstable electrode structure.However,the presence of rGO could efficiently suppress the decomposition of electrolyte,thus thin and stable SEI film was formed.ZnSe@C electrodes wrapped by rGO demonstrates enhanced interfacial charge transfer kinetics and high electrochemical performance,a capacity retention of 96.4%,after 1000 cycles at 5 A/g.This study might offer a simple avenue for the designing high performance anode materials through manipulation of SEI film.展开更多
Our previous study found that large-leaf yellow tea(LYT)had interesting hypoglycemic activity in high-fat diet-induced obese mice and highly safety in healthy mice. To study the anti-diabetic potential of LYT, the pre...Our previous study found that large-leaf yellow tea(LYT)had interesting hypoglycemic activity in high-fat diet-induced obese mice and highly safety in healthy mice. To study the anti-diabetic potential of LYT, the present study further investigated the preventive effects and mechanisms of action of LYT administration on diabetes and diabetic nephropathy in high-fat diet plus streptozotocin-induced diabetic mice. Results showed that LYT infusions(1/100 and 1/50, m/V)as drinking fluid for 4 weeks reduced diabetic polydipsia and polyuria, enhanced glucose tolerance and insulin sensitivity, and lowered fasting blood glucose level. The underlying mechanisms involve downregulation of gluconeogenesis(lower protein levels of TXNIP and FBP and enzyme activity of FBP), upregulation of lipid catabolism(higher protein levels of CPT-1α and PPARα), downregulation of lipogenesis(lower protein level of SREBP-1), and modification of the structure and abundance of gut microbiota to modulate metabolic homeostasis. Moreover, LYT administration prevented diabetic nephropathy, possibly due to reduced glucose-caused osmotic diuresis and lowered levels of renal PKC-β2, NLRP3 as well as membrane PKC-α, AQP2 and glycosylated AQP2 proteins. Taken together, LYT exhibits the activities in alleviating diabetic symptoms, ameliorating glucose and lipid dysmetabolism and fatty liver, and preventing diabetic nephropathy in diabetic mice. These activities may be explored for the prevention and treatment of diabetes in humans.展开更多
Objective To determine whether testosterone modulates markers of cardiomyocytes aging via its classic androgen receptor （AR）-dependent pathway or conversion to estradiol. Methods Male littermates and testicular fem...Objective To determine whether testosterone modulates markers of cardiomyocytes aging via its classic androgen receptor （AR）-dependent pathway or conversion to estradiol. Methods Male littermates and testicular feminized （Tfm） mice were randomly separated into 4 experimental groups： littermate controls （n=8）, Tfm mice （n=7）, testosterone-treated Tfm mice （n=8） and Tfm mice treated with testosterone in combination with the aromatase inhibitor anastrazole （n=7）. Cardiomyocytes were isolated from mouse left ventricles, the activity of superoxide dismutase （SOD） and glutathione peroxidase （GSH-Px）, and the amount of malondialdehyde （MDA） were measured us- ing colorimetry method, and expression of p l 6~NKga and retinoblastoma （Rb） proteins were detected by Western blotting. Results The SOD and GSH-Px enzyme activities of cardiomyocytes were decreased, and the MDA levels and the expression of p l 6INK＊a and Rb proteins were increased in Tfm mice compared with control mice. An increase was observed in the activities of SOD and GSH-Px enzyme as well as a decrease in MDA levels and the expression of p 16~NK4a and Rb proteins in the testosterone-treated Tfm mice. After co-treatment with anastrazole in Tfm mice, these improvement were partly inhib- ited. Conclusion Physiological testosterone replacement can delay cardiomyocyte aging in Tfm mice, an effect that is independent of the AR pathway and in part conversion to estradiol.展开更多
The catalysts Ni/Al2O3, Ni/ZrO2-CeO2-Al2O3 and Ni/CuO-ZrO2-CeO2-Al2O3 were prepared by the co-precipitation method at a pH of 9 using Na2CO3 as the precipitant. The Ni loading(mass fraction) of the catalysts was 10%. ...The catalysts Ni/Al2O3, Ni/ZrO2-CeO2-Al2O3 and Ni/CuO-ZrO2-CeO2-Al2O3 were prepared by the co-precipitation method at a pH of 9 using Na2CO3 as the precipitant. The Ni loading(mass fraction) of the catalysts was 10%. The ignition process on the catalysts for the autothermal reforming of methane to hydrogen was investigated and the surface properties of the catalysts were characterized by XPS. The results showed that the Ni/Al2O3 catalyst could not ignite the process of autothermal reforming of methane to hydrogen. However, the Ni/CuO-ZrO2-CeO2-Al2O3 catalyst could ignite the process of autothermal reforming of methane to hydrogen at lower reaction temperature(650 ℃) with the conversion of methane reaching 76%. The result of XPS analysis indicated that the promoters could change the binding energy(BE) of Ni2p3/2 obviously. The species of Cu in the Ni/CuO-ZrO2-CeO2-Al2O3 catalyst comprised Cu2 O and Cu2+. The formation of ZrO2-CeO2 solid solution and a large amount of Cu2 O might be the reason leading to good oxygen storage capacity and mobility of lattice oxygen of the Ni/CuO-ZrO2-CeO2-Al2O3 catalyst, which could ignite the process of autothermal reforming of methane to hydrogen at lower reaction temperature.展开更多
Prevalence of dislipidemia is increasing rapidly in China and there has been a growing interest in Chinese herbal medicine for the treatment of hyperlipidemia both inside and outside China. In this article, lipids reg...Prevalence of dislipidemia is increasing rapidly in China and there has been a growing interest in Chinese herbal medicine for the treatment of hyperlipidemia both inside and outside China. In this article, lipids regulating effects of 9 herbs or their extracts and 5 herbal formulae which have been published in English-language literature are reviewed. Although evidence from animals and humans consistently supports the therapeutic activities of these Chinese herbal medicines, few multi-center large-scale clinical trials have been conducted to confirm the efficacy and evaluate their safety.展开更多
Developing Earth-abundant,highly efficient,and anticorrosion electrocatalysts to boost the oxygen evolution reaction(OER),oxygen reduction reaction(ORR),and hydrogen evolution reaction(HER) for the Zn–air battery(ZAB...Developing Earth-abundant,highly efficient,and anticorrosion electrocatalysts to boost the oxygen evolution reaction(OER),oxygen reduction reaction(ORR),and hydrogen evolution reaction(HER) for the Zn–air battery(ZAB) and for overall water splitting is imperative.In this study,a novel process starting with Cu2O cubes was developed to fabricate hollow NixCo1-xSe nanocages as trifunctional electrocatalysts for the OER,ORR,and HER and a reasonable formation mechanism was proposed.The Ni0.2Co0.8Se nanocages exhibited higher OER activity than its counterparts with the low overpotential of 280 mV at 10 mA cm-2.It also outperformed the other samples in the HER test with a low overpotential of 73 mV at 10 mA cm-2.As an air–cathode of a self-assembled rechargeable ZAB,it exhibited good performance,such as an ultralong cycling lifetime of > 50 h,a high round-trip efficiency of 60.86%,and a high power density of 223.5 mW cm-2.For the application in self-made all-solid-state ZAB,it also demonstrated excellent performance with a power density of 41.03 mW cm-2 and an open-circuit voltage of 1.428 V.In addition,Ni0.2Co0.8Se nanocages had superior performance in a practical overall water splitting,in which only 1.592 V was needed to achieve a current density of 10 mA cm-2.These results show that hollow NixCo1-xSe nanocages with an optimized Ni-to-Co ratio are a promising cost-effective and high-efficiency electrocatalyst for ZABs and overall water splitting in alkaline solutions.展开更多
O’Neill’s tragedy deeply rooted in his own life experience and his family heredity.He is an offspring of Irish immi grants,his homelessness as a child,his early education in the catholic school and his later break w...O’Neill’s tragedy deeply rooted in his own life experience and his family heredity.He is an offspring of Irish immi grants,his homelessness as a child,his early education in the catholic school and his later break with religion,his foreign expedi tion,life on the sea and his three marriages all influenced his life and his career and his theme decisively.展开更多
Dual antiplatelet therapy(DAPT)with aspirin and clopidogrel has been widely used after percutaneous coronary intervention(PCI).The bleeding complications caused by it cannot be ignored and the incidence is as high as ...Dual antiplatelet therapy(DAPT)with aspirin and clopidogrel has been widely used after percutaneous coronary intervention(PCI).The bleeding complications caused by it cannot be ignored and the incidence is as high as 32.4%.[1]Among them,spinal cord hemorrhage is rare,acute and life-threatening.We herein report a case of spinal cord hemorrhage caused by DAPT with aspirin and clopidogrel used after PCI for non-ST elevation myocardial infarction(NSTEMI).展开更多
The allelopathic potential of Rhus chinensis Mill on seedling growth of radish（Raphanus sativus L.）,semen cassiae（seed of Cassia obtusifolia L.） and black soyabean [Glycine max（L.） Merr.] was investigated under ...The allelopathic potential of Rhus chinensis Mill on seedling growth of radish（Raphanus sativus L.）,semen cassiae（seed of Cassia obtusifolia L.） and black soyabean [Glycine max（L.） Merr.] was investigated under laboratory conditions.The water extracts of seed,leaf and bark of R.chinensis inhibited the germination and the growth of roots and shoots of radish,semen cassiae,and black soyabean.Significant increasing reductions in the germination and growth of roots and shoots were observed as the concentration of water extract increased in all bioassays.The order of allelopathic potentials of the three parts from R.chinensis plant on seed germination of these receptors was leaf [ seed [ bark.However,the inhibition of water extracts from R.chinensis seed on root activity of semen cassiae was more severe than from the other two parts.The allelopathic potential on the germination of radish was higher than that of black soyabean and semen cassiae.The integrated effect index for allelopathic potential of water extracts of leaf of R.chinensis on radish,semen cassiae and black soyabean seedling growth were-0.88,-0.93 and-0.98 respectively.The results suggested that it is important to minimize the negative allelopathic potential of R.chinensis in agroforestry systems,and to exploit this traditional Chinese medicinal tree for the production of natural bio-pesticides.展开更多
In this study,lipases of CALB(Candida antarctica lipase B),TLL(Thermomyces lanuginosa lipase),RML(Rhizomucor miehei lipase),CALA(Candida antarctica lipase A)and LU(Lecitase?Ultra)were encapsulated into the nucleotideh...In this study,lipases of CALB(Candida antarctica lipase B),TLL(Thermomyces lanuginosa lipase),RML(Rhizomucor miehei lipase),CALA(Candida antarctica lipase A)and LU(Lecitase?Ultra)were encapsulated into the nucleotidehybrid metal coordination polymers(CPs)for diacylglyerols(DAG)preparation.Guanosine 5'-monophosphate(GMP)and adenosine 5'-monophosphate(AMP)were used as coordinating molecules,and metal ions of Fe^(3+),Ba^(2+),Mn^(2+),Ni^(2+)and Cr^(3+)were applied to prepare matrix.Results indicated that,besides Ba^(2+)with AMP,all other metal ions can coordinate with AMP and GMP to generate CPs.In addition,the AMP/Ni was amorphous when standing temperature was 4℃,while it was crystalline when standing temperature was from 30 to 180℃.DAG content from 47.55%to 64.99%was obtained from glycerolysis by CALB@GMP/Ba,RML@GMP/Ba,TLL@GMP/Ba,RML@GMP/Mn and TLL@GMP/Mn.Additionally,CALB@GMP/Fe showed selectivity towards DAG formation in the esterification and DAG content up to 61.88%was obtained.展开更多
In this paper,an eco-epidemiological model with time delay is studied.The local stability of the four equilibria,the existence of stability switches about the predationfree equilibrium and the coexistence equilibrium ...In this paper,an eco-epidemiological model with time delay is studied.The local stability of the four equilibria,the existence of stability switches about the predationfree equilibrium and the coexistence equilibrium are discussed.It is found that Hopf bifurcations occur when the delay passes through some critical values.Formulae are obtained to determine the direction of bifurcations and the stability of bifurcating periodic solutions by using the normal form theory and center manifold theorem.Some numerical simulations are carried out to illustrate the theoretical results.展开更多
Leprosy is characterized by skin lesions and peripheral nerve damage. It may take a long time before the diagnosis can be confirmed if the patients have no typical skin involvements. Here we report an unusual case. A ...Leprosy is characterized by skin lesions and peripheral nerve damage. It may take a long time before the diagnosis can be confirmed if the patients have no typical skin involvements. Here we report an unusual case. A 40-year-old male with lepromatous leprosy showed a gradual onset of bilateral symmetrical neuropathies without characteristic skin manifestations seven years after onset and with pulmonary tuberculosis simultaneously. He was misdiagnosed as having Guillani-Barr6 syndrome and systemic necrotizing vasculitis for 10 years until the skin biopsy was performed. This case indicates that the risk of leprosy exists, though new cases being detected have significantly declined over the last 50 years; neurologists need to pay more attention to leprosy with various manifestations .展开更多
基金supported by the National Natural Science Foundation of China(12071491,12001113)。
文摘In this paper,we consider a class of third-order nonlinear delay dynamic equations.First,we establish a Kiguradze-type lemma and some useful estimates.Second,we give a sufficient and necessary condition for the existence of eventually positive solutions having upper bounds and tending to zero.Third,we obtain new oscillation criteria by employing the Potzsche chain rule.Then,using the generalized Riccati transformation technique and averaging method,we establish the Philos-type oscillation criteria.Surprisingly,the integral value of the Philos-type oscillation criteria,which guarantees that all unbounded solutions oscillate,is greater than θ_(4)(t_(1),T).The results of Theorem 3.5 and Remark 3.6 are novel.Finally,we offer four examples to illustrate our results.
基金This work was supported by the National Natural Science Foundation of China(82172511)the Natural Science Foundation of Jiangsu Province(BK20210068)+4 种基金the Sanming Project of Medicine in Shenzhen(SZSM201612078)the Health Shanghai Initiative Special Fund[Medical-Sports Integration(JKSHZX-2022-02)]the Top Talent Support Program for Young-and Middle-aged People of Wuxi Municipal Health Commission(HB2020003)the Mega-project of Wuxi Commission of Health(Z202216)the High-end Medical Expert Team of the 2019 Taihu Talent Plan(2019-THRCTD-1)
文摘Dear Editor,Physical exercise has been shown to be associated with reduced cancer incidence and cancer-associated mortality[1,2],but the underlying mechanisms are obscure.Immunometabolic regulation has emerged as one of the most prominent mechanisms explaining the effects of exercise on cancer[1,2].Physical exercise primarily lowers blood cholesterol and triglycerides,and protects against cardiovascular diseases[3].However,whether physical exercise can modulate cholesterol metabolism in tumor cells is currently unknown.
基金supported by the National Natural Science Foundation of China (U2032151)the National Key R&D Program of China (2018YFB1502600)+1 种基金the Basic Research and Applied Basic Research Foundation of Guangzhou (B3210580)the Natural Science Foundation of Guangdong Province (B6211050)。
文摘The alkaline hydrogen evolution reaction(HER) on Pt-based catalysts is largely limited by the slow water dissociation kinetics. Pt-based single atom alloy catalysts(SAAC) with water dissociation sites have been demonstrated as excellent alkaline HER catalysts. However, the regulation of their activity and stability at the atomic scale is still a great challenge. Herein, the kinetic and stability issues are successfully resolved via engineering the electronic structure of Pt-Co SAAC by Au-induced tensile strain. The atomic dispersion of Co into the Pt shell was confirmed by extended X-ray absorption fine structure and the electronic structure and catalytic HER performance was modulated by the tensile strain induced by the Pt shell thickness. An inverse volcano-type relation between HER activity and surface strain was found.Density functional theory(DFT) calculations reveal that the Au-induced tensile strain on Pt-Co shell can not only boost the adsorption and dissociation kinetics of water at Co site by upshifting the dband and promoting the electron transfer, but also downshift the d-band center of Pt in Pt-Co shell, leading to optimized H* adsorption/desorption. The champion catalyst provides an overpotential of only 14 m V at the current density of 10 mA cm^(-2). This work not only provides an effective strategy for the construction of single-atom alloy electrocatalysts for high performance toward alkaline HER but also sheds light on the understanding of the reaction mechanism at the atomic level.
基金supported by the Natural Science Foundation of Guangdong Province(030514)the Science and Technology Plan of Guangdong Province(2004B33401006).
文摘The effect of promoter Ce on the catalytic performance of Ni/Al2O3 catalyst for autothermal reforming of methane to hydrogen was investigated. The catalysts were characterized by X-ray diffraction （XRD）, temperature-programmed reduction （TPR）, and X-ray photoelectron spectroscopy （XPS）. The results indicated that the catalytic performance of the catalysts was improved with the addition of Ce. Ni/Ce30Al70Oδ showed the highest CH4 conversion in operation temperatures ranging from 650 ℃ to 850 ℃. At the same time, the decrease in H2/CO ratio with increasing reaction temperature was consistent with the fact that water-gas shift reaction was thermodynamically unfavorable at higher temperatures. The XRD result indicated that adding Ce to Ni/Al2O3 catalyst prevented the formation of NiAl2O4 and facilitated the formation of NiO. The formation of NiO increased the number of active sites, resulting in higher activity. Comparing the TPR profiles of Ni/Ce30Al70Oδ with Ni/Al2O3, it could be clearly observed that with the addition of Ce, the total reduction peak areas in the middle and low temperatures increased. It was most probably that the addition of Ce inhibited the stronger interaction between Ni and Al2O3 to form the phase of NiAl2O4, and favored the formation of the strong interaction between NiO species and CeO2. Therefore, the addition of Ce to the Ni/Al2O3 catalyst increased the active surface that promoted the activity of the catalyst.
基金supported by Guangdong Provincial Natural Science Foundation of China(030514)Science and Technology Plan of Guangdong Province of China(2004B33401006)Doctoral Startup Foundation of Guang Dong Pharmaceutical University.
文摘Ni catalysts supported on Al2O3, ZrO2-Al2O3, CeO2-Al2O3 and ZrO2-CeO2-Al2O3 were prepared by coprecipitation method, and their catalytic performances for autothermal reforming of methane to hydrogen were investigated. The Ni-supported catalysts were characterized by XRD, TPR and XPS. The relationship between the structures and catalytic activities of the catalysts was discussed. The results showed that the catalytic activity and stability of the Ni/ZrO2-CeO2-Al2O3 catalyst was better than those of other catalysts with the highest CH4 conversion, H2/CO and H2/COx ratio at 750 ℃. The catalyst showed a little deactivation along the reaction time during its 72 h on stream with the mean deactivation rate of 0.08%/h. The catalytic performance of the Ni/ZrO2-CeO2-Al2O3 catalyst was also affected by reaction temperature, no2 ： nCH4 molar ratio and nH2O ： nCH4 molar ratio. TPR, XRD and XPS measurements indicated that the formation of ZrO2-CeO2 solid solution could improve the dispersion of NiO, and inhibit the formation of NiAl2O3, and thus significantly promoted the catalytic activity of the Ni/ZrO2-CeO2-Al2O3 catalyst.
基金Project 2007GGW03 supported by the Science Research Foundation of Guangdong Pharmaceutical University
文摘A spectrophotometric method for the determination of ruthenium(III) is described, based on its catalytic effect on the oxidation reaction of dimethyl yellow (DMY) with potassium bromate in an acid solution medium and in the presence of an OP emulsifier (p-iso-octyl phenoxy polyethoxy ethanol) at 100 °C. This reaction was followed spectrophotometrically by measuring the decrease in the absorbance at 530 nm of the catalytic reaction of DMY. The calibration curve for the recommended method was linear in the concentration range over 0.0–1.0 μg/L and the detection limit of the method for Ru(III) was 0.01 μg/L. The method is highly sensitive, selective and very stable and has been successfully applied for the determination of trace amounts of ruthenium in some ores and metallurgy products with the relative standard deviations (RSD) over 1.6%–2.8% and a recovery over 98.7%–104.0%.
基金Key-Area Research and Development Program of Guangdong Province(2018B020206001)Guangdong Provincial Agricultural Science and Technology Innovation and Extension Project in 2019(2019KJ101)+1 种基金National key research and development plan(2018YFC1604105)National Natural Science Foundation of China(81703053).
文摘The high-glucose tolerance of yeast is the main factor determining the efficiency of high-density alcohol fermentation.Zygosaccharomyces mellis LGL-1 isolated from honey could survive under 700 g/L high-glucose stress and its tolerant characteristics were identified in our previous study.This study was performed to explore and clarify the high-glucose tolerance mechanism of Z.mellis LGL-1.Comparative transcriptomic analysis was used to analyze the genes with differential expression in Z.mellis under high-glucose conditions of 300,500 and 700 g/L.With 300 g/L samples as reference,there were 937 and 2380 differentially expressed genes(DEGs)in the 500 and 700 g/L samples,respectively.Meanwhile,there was 825 significant DEGs in the 700 g/L samples compared with that of the 500 g/L samples.The result revealed that transcriptional changes in multiple metabolic pathways occur in response to high-glucose stress.q-RT PCR analysis further confirmed that several stress response pathways,such as the high osmolarity glycerol mitogen-activated protein kinase(HOG-MAPK)signal transduction pathway,trehalose synthesis pathway and oxidative stress response are closely related to high-glucose tolerance in Z.mellis.This study clarifies mechanisms of Z.mellis in response to high-glucose osmotic stress,providing theoretical basis for the process control of high-density alcohol fermentation.
基金supported by the Fundamental Research Funds for Central Universities(SCUT Grant No.2019ZD22)the Guangdong Innovative and Entrepreneurial Research Team Program(No.2016ZT06N569)。
文摘Transition metal selenides have been widely studied as anode materials of sodium ion batteries(SIBs),however,the investigation of solid-electrolyte-interface(SEI)on these materials,which is critical to the electrochemical performance of SIBs,remains at its infancy.Here in this paper,ZnSe@C nanoparticles were prepared from ZIF-8 and the SEI layers on these electrodes with and without reduced graphene oxide(rGO)layers were examined in details by X-ray photoelectron spectroscopies at varied charged/discharged states.It is observed that fast and complicated electrolyte decomposition reactions on ZnSe@C leads to quite thick SEI film and intercalation of solvated sodium ions through such thick SEI film results in slow ion diffusion kinetics and unstable electrode structure.However,the presence of rGO could efficiently suppress the decomposition of electrolyte,thus thin and stable SEI film was formed.ZnSe@C electrodes wrapped by rGO demonstrates enhanced interfacial charge transfer kinetics and high electrochemical performance,a capacity retention of 96.4%,after 1000 cycles at 5 A/g.This study might offer a simple avenue for the designing high performance anode materials through manipulation of SEI film.
基金supported by the Open Fund of State Key Laboratory of Tea Plant Biology and Utilization (SKLTOF20200127 and SKLT0F20200108)the Open Fund of Key Laboratory of Tea Plant Resources Comprehensive Development in South Henan Province (HNKLTOF2020005)the Zhejiang Provincial Basic Public Welfare Research Program Project (LGF20H280007)。
文摘Our previous study found that large-leaf yellow tea(LYT)had interesting hypoglycemic activity in high-fat diet-induced obese mice and highly safety in healthy mice. To study the anti-diabetic potential of LYT, the present study further investigated the preventive effects and mechanisms of action of LYT administration on diabetes and diabetic nephropathy in high-fat diet plus streptozotocin-induced diabetic mice. Results showed that LYT infusions(1/100 and 1/50, m/V)as drinking fluid for 4 weeks reduced diabetic polydipsia and polyuria, enhanced glucose tolerance and insulin sensitivity, and lowered fasting blood glucose level. The underlying mechanisms involve downregulation of gluconeogenesis(lower protein levels of TXNIP and FBP and enzyme activity of FBP), upregulation of lipid catabolism(higher protein levels of CPT-1α and PPARα), downregulation of lipogenesis(lower protein level of SREBP-1), and modification of the structure and abundance of gut microbiota to modulate metabolic homeostasis. Moreover, LYT administration prevented diabetic nephropathy, possibly due to reduced glucose-caused osmotic diuresis and lowered levels of renal PKC-β2, NLRP3 as well as membrane PKC-α, AQP2 and glycosylated AQP2 proteins. Taken together, LYT exhibits the activities in alleviating diabetic symptoms, ameliorating glucose and lipid dysmetabolism and fatty liver, and preventing diabetic nephropathy in diabetic mice. These activities may be explored for the prevention and treatment of diabetes in humans.
基金Supported by National Basic Research Program of China(973 Program,2007CB507404)
文摘Objective To determine whether testosterone modulates markers of cardiomyocytes aging via its classic androgen receptor （AR）-dependent pathway or conversion to estradiol. Methods Male littermates and testicular feminized （Tfm） mice were randomly separated into 4 experimental groups： littermate controls （n=8）, Tfm mice （n=7）, testosterone-treated Tfm mice （n=8） and Tfm mice treated with testosterone in combination with the aromatase inhibitor anastrazole （n=7）. Cardiomyocytes were isolated from mouse left ventricles, the activity of superoxide dismutase （SOD） and glutathione peroxidase （GSH-Px）, and the amount of malondialdehyde （MDA） were measured us- ing colorimetry method, and expression of p l 6~NKga and retinoblastoma （Rb） proteins were detected by Western blotting. Results The SOD and GSH-Px enzyme activities of cardiomyocytes were decreased, and the MDA levels and the expression of p l 6INK＊a and Rb proteins were increased in Tfm mice compared with control mice. An increase was observed in the activities of SOD and GSH-Px enzyme as well as a decrease in MDA levels and the expression of p 16~NK4a and Rb proteins in the testosterone-treated Tfm mice. After co-treatment with anastrazole in Tfm mice, these improvement were partly inhib- ited. Conclusion Physiological testosterone replacement can delay cardiomyocyte aging in Tfm mice, an effect that is independent of the AR pathway and in part conversion to estradiol.
基金supported by the Guangdong Provincial Natural Science Foundation (030514)the Science and Technology Plan of Guangdong Province of China (2004B33401006)the Doctoral Startup Foundation of Guangdong Pharmaceutical University
文摘The catalysts Ni/Al2O3, Ni/ZrO2-CeO2-Al2O3 and Ni/CuO-ZrO2-CeO2-Al2O3 were prepared by the co-precipitation method at a pH of 9 using Na2CO3 as the precipitant. The Ni loading(mass fraction) of the catalysts was 10%. The ignition process on the catalysts for the autothermal reforming of methane to hydrogen was investigated and the surface properties of the catalysts were characterized by XPS. The results showed that the Ni/Al2O3 catalyst could not ignite the process of autothermal reforming of methane to hydrogen. However, the Ni/CuO-ZrO2-CeO2-Al2O3 catalyst could ignite the process of autothermal reforming of methane to hydrogen at lower reaction temperature(650 ℃) with the conversion of methane reaching 76%. The result of XPS analysis indicated that the promoters could change the binding energy(BE) of Ni2p3/2 obviously. The species of Cu in the Ni/CuO-ZrO2-CeO2-Al2O3 catalyst comprised Cu2 O and Cu2+. The formation of ZrO2-CeO2 solid solution and a large amount of Cu2 O might be the reason leading to good oxygen storage capacity and mobility of lattice oxygen of the Ni/CuO-ZrO2-CeO2-Al2O3 catalyst, which could ignite the process of autothermal reforming of methane to hydrogen at lower reaction temperature.
文摘Prevalence of dislipidemia is increasing rapidly in China and there has been a growing interest in Chinese herbal medicine for the treatment of hyperlipidemia both inside and outside China. In this article, lipids regulating effects of 9 herbs or their extracts and 5 herbal formulae which have been published in English-language literature are reviewed. Although evidence from animals and humans consistently supports the therapeutic activities of these Chinese herbal medicines, few multi-center large-scale clinical trials have been conducted to confirm the efficacy and evaluate their safety.
基金the Guangzhou Science and Technology Plan Projects(No.201804010323)the Guangdong Natural Science Funds for Distinguished Young Scholars(No.2015A030306006)+3 种基金the Guangdong Innovative and Entrepreneurial Research Team Program(No.2014ZT05N200)the Fundamental Research Funds for the Central Universities(SCUT Grant No.2018ZD022)the Project for Natural Science Foundation of Guangdong Province(No.2018A030313178)the funding support from the Natural Science Foundation of Guangdong Province(No.2015A030310176)
文摘Developing Earth-abundant,highly efficient,and anticorrosion electrocatalysts to boost the oxygen evolution reaction(OER),oxygen reduction reaction(ORR),and hydrogen evolution reaction(HER) for the Zn–air battery(ZAB) and for overall water splitting is imperative.In this study,a novel process starting with Cu2O cubes was developed to fabricate hollow NixCo1-xSe nanocages as trifunctional electrocatalysts for the OER,ORR,and HER and a reasonable formation mechanism was proposed.The Ni0.2Co0.8Se nanocages exhibited higher OER activity than its counterparts with the low overpotential of 280 mV at 10 mA cm-2.It also outperformed the other samples in the HER test with a low overpotential of 73 mV at 10 mA cm-2.As an air–cathode of a self-assembled rechargeable ZAB,it exhibited good performance,such as an ultralong cycling lifetime of > 50 h,a high round-trip efficiency of 60.86%,and a high power density of 223.5 mW cm-2.For the application in self-made all-solid-state ZAB,it also demonstrated excellent performance with a power density of 41.03 mW cm-2 and an open-circuit voltage of 1.428 V.In addition,Ni0.2Co0.8Se nanocages had superior performance in a practical overall water splitting,in which only 1.592 V was needed to achieve a current density of 10 mA cm-2.These results show that hollow NixCo1-xSe nanocages with an optimized Ni-to-Co ratio are a promising cost-effective and high-efficiency electrocatalyst for ZABs and overall water splitting in alkaline solutions.
文摘O’Neill’s tragedy deeply rooted in his own life experience and his family heredity.He is an offspring of Irish immi grants,his homelessness as a child,his early education in the catholic school and his later break with religion,his foreign expedi tion,life on the sea and his three marriages all influenced his life and his career and his theme decisively.
文摘Dual antiplatelet therapy(DAPT)with aspirin and clopidogrel has been widely used after percutaneous coronary intervention(PCI).The bleeding complications caused by it cannot be ignored and the incidence is as high as 32.4%.[1]Among them,spinal cord hemorrhage is rare,acute and life-threatening.We herein report a case of spinal cord hemorrhage caused by DAPT with aspirin and clopidogrel used after PCI for non-ST elevation myocardial infarction(NSTEMI).
基金supported by the Major State Basic Research Development Program(973)of China(No.2011CB100400)Sci-technology Program of Guangdong Province(No.0203-E12147)
文摘The allelopathic potential of Rhus chinensis Mill on seedling growth of radish（Raphanus sativus L.）,semen cassiae（seed of Cassia obtusifolia L.） and black soyabean [Glycine max（L.） Merr.] was investigated under laboratory conditions.The water extracts of seed,leaf and bark of R.chinensis inhibited the germination and the growth of roots and shoots of radish,semen cassiae,and black soyabean.Significant increasing reductions in the germination and growth of roots and shoots were observed as the concentration of water extract increased in all bioassays.The order of allelopathic potentials of the three parts from R.chinensis plant on seed germination of these receptors was leaf [ seed [ bark.However,the inhibition of water extracts from R.chinensis seed on root activity of semen cassiae was more severe than from the other two parts.The allelopathic potential on the germination of radish was higher than that of black soyabean and semen cassiae.The integrated effect index for allelopathic potential of water extracts of leaf of R.chinensis on radish,semen cassiae and black soyabean seedling growth were-0.88,-0.93 and-0.98 respectively.The results suggested that it is important to minimize the negative allelopathic potential of R.chinensis in agroforestry systems,and to exploit this traditional Chinese medicinal tree for the production of natural bio-pesticides.
基金the National Natural Science Foundation of China(31772000)。
文摘In this study,lipases of CALB(Candida antarctica lipase B),TLL(Thermomyces lanuginosa lipase),RML(Rhizomucor miehei lipase),CALA(Candida antarctica lipase A)and LU(Lecitase?Ultra)were encapsulated into the nucleotidehybrid metal coordination polymers(CPs)for diacylglyerols(DAG)preparation.Guanosine 5'-monophosphate(GMP)and adenosine 5'-monophosphate(AMP)were used as coordinating molecules,and metal ions of Fe^(3+),Ba^(2+),Mn^(2+),Ni^(2+)and Cr^(3+)were applied to prepare matrix.Results indicated that,besides Ba^(2+)with AMP,all other metal ions can coordinate with AMP and GMP to generate CPs.In addition,the AMP/Ni was amorphous when standing temperature was 4℃,while it was crystalline when standing temperature was from 30 to 180℃.DAG content from 47.55%to 64.99%was obtained from glycerolysis by CALB@GMP/Ba,RML@GMP/Ba,TLL@GMP/Ba,RML@GMP/Mn and TLL@GMP/Mn.Additionally,CALB@GMP/Fe showed selectivity towards DAG formation in the esterification and DAG content up to 61.88%was obtained.
文摘In this paper,an eco-epidemiological model with time delay is studied.The local stability of the four equilibria,the existence of stability switches about the predationfree equilibrium and the coexistence equilibrium are discussed.It is found that Hopf bifurcations occur when the delay passes through some critical values.Formulae are obtained to determine the direction of bifurcations and the stability of bifurcating periodic solutions by using the normal form theory and center manifold theorem.Some numerical simulations are carried out to illustrate the theoretical results.
文摘Leprosy is characterized by skin lesions and peripheral nerve damage. It may take a long time before the diagnosis can be confirmed if the patients have no typical skin involvements. Here we report an unusual case. A 40-year-old male with lepromatous leprosy showed a gradual onset of bilateral symmetrical neuropathies without characteristic skin manifestations seven years after onset and with pulmonary tuberculosis simultaneously. He was misdiagnosed as having Guillani-Barr6 syndrome and systemic necrotizing vasculitis for 10 years until the skin biopsy was performed. This case indicates that the risk of leprosy exists, though new cases being detected have significantly declined over the last 50 years; neurologists need to pay more attention to leprosy with various manifestations .
