Experimental and theoretical investigations of the photoelectrochemical and photo-Fenton properties of Co-doped FeOCl

For the first time,two-dimensional FeOCl(Fe_(1-x)Co_(x)OCl)doped with Co was successfully applied to the photocatalytic and photo-Fenton degradation of Rhodamine B(RhB).The photocatalytic and photo-Fenton experiments showed that the degradation rates of RhB by Fe0.94Co0.06OCl are 82.6%and 98.2%within 50 min under neutral solution,room temperature and visible light.The inclusion of Co resulted in lattice imperfections on the surface of Fe OCl,which was advantageous for the photogenerated electron-hole pair separation efficiency(consistent with the density functional theory calculation).Moreover,the RhB removal rate decreased from 98%to 82%during five successive cycles,showing good structural stability.Finally,based on the radical capture experiment,a potential mechanism for RhB degradation by Fe_(1-x)Co_(x)OCl catalyst was proposed.The idea of a synergistic mechanism for Fe_(1-x)Co_(x)OCl also offers a fresh concept for catalysts used in doping modification.

Curcumin inhibits hepatitis B virus infection by downregulating ccc DNA-bound histone acetylation

AIM To investigate the potential effect of curcumin on hepatitis B virus(HBV) covalently closed circular DNA(ccc DNA) and the underlying mechanism.METHODS A Hep G2.2.15 cell line stably transfected with HBV was treated with curcumin, and HBV surface antigen(HBs Ag) and e antigen(HBe Ag) expression levels were assessed by ELISA. Intracellular HBV DNA replication intermediates and ccc DNA were detected by Southern blot and real-time PCR, respectively. The acetylation levels of histones H3 and H4 were measured by Western blot. H3/H4-bound ccc DNA was detected by chromatin immunoprecipitation(Ch IP) assays. The deacetylase inhibitors trichostatin A and sodium butyrate were used to study the mechanism of action for curcumin. Additionally, short interfering RNAs(si RNAs) targeting HBV were tested along with curcumin.RESULTS Curcumin treatment led to time-and dose-dependent reductions in HBs Ag and HBe Ag expression and significant reductions in intracellular HBV DNA replication intermediates and HBV ccc DNA. After treatment with 20 μmol/L curcumin for 2 d, HBs Ag and ccc DNA levels in Hep G2.2.15 cells were reduced by up to 57.7%(P < 0.01) and 75.5%(P < 0.01), respectively, compared with levels in non-treated cells. Meanwhile, time-and dose-dependent reductions in the histone H3 acetylation levels were also detected upon treatment with curcumin, accompanied by reductions in H3-and H4-bound ccc DNA. Furthermore, the deacetylase inhibitors trichostatin A and sodium butyrate could block the effects of curcumin. Additionally, transfection of si RNAs targeting HBV enhanced the inhibitory effects of curcumin.CONCLUSION Curcumin inhibits HBV gene replication via downregulation of ccc DNA-bound histone acetylation and has the potential to be developed as a ccc DNA-targeting antiviral agent for hepatitis B.

Microstructure and photocatalytic activity of Ni-doped ZnS nanorods prepared by hydrothermal method

Pure ZnS and Ni^2+-doped ZnS nanorods (Zn1-xNixS, x=0, 0.01, 0.03, 0.05 and 0.07, mole fraction,%) were synthesized by hydrothermal method. The effects of Ni2+ doping on the phase-structure, morphology, elemental composition and optical properties of the samples were investigated by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), X-ray energy dispersive spectrometry (EDS) and ultraviolet–visible spectroscopy (UV-Vis), respectively. The photocatalytic activity of Zn1-xNixS nanorods was evaluated by the photodegradation of organic dyes Rhodamine B (RhB) in aqueous solution under UV light irradiation. The results show that all samples exhibit wurtzite structure with good crystallization. The morphologies are one-dimensional nanorods with good dispersion, and the distortion of the lattice constant occurs. The band gap of Zn1-xNixS samples is smaller than that of pure ZnS, thus red shift occurs. Ni^2+-doped ZnS nanocrystals can enhance photocatalytic activities for the photodegradation of RhB. Especially, Zn0.97Ni0.03S sample exhibits better photocatalytic performance and photocatalytic stability for the decomposition of RhB.

Relationship between sKL, BSP and HD abdominal aortic calcification and prognosis

Objective: To investigate the relationship between the expression levels of sKL and BSP and the calcification and prognosis of abdominal aorta in patients with HD. Methods: 130 patients with HD admitted to our hospital between January 2015 and June 2017 were selected as the research subjects;all patients were treated with Fresenius hemodialysis machine for intervention treatment;the expression levels of sKL and BSP in the patients' blood were monitored, and 30 mmonths were followed up The extent of calcification of the abdominal aorta and the quality of the prognosis of the patients were evaluated and the relationship between the expression levels of sKL and BSP and the calcification and prognosis of the abdominal aorta were analyzed. Results: The levels of sKL and BSP in the blood of patients with different degrees of abdominal aortic calcification were significantly different, and the differences were statistically significant (P <0.05). Among the patients with mild or no calcification, the levels of sKL and BSP were the highest in the blood and those in the death group were the lowest. The sKL level was significantly lower than the survival group, and the BSP level was significantly higher than the survival group, and the differences were statistically significant (P <0.05);the survival rate of patients with high sKL expression was significantly better than that of patients with low sKL expression, and the survival rate of low BSP expression was significantly better High expression in BSP;high sKL and low BSP are independent protective factors affecting abdominal aortic calcification and prognostic quality in HD patients (P <0.05);combined use of sKL and BSP in predicting the prognostic quality of HD patients is sensitive and specific Both are greater than 90%, and AUC> 0.90. Conclusions:High sKL and low BSP in the blood of HD patients are independent protective factors affecting abdominal aortic calcification and prognostic quality. The combined application of sKL and BSP can effectively predict the prognostic quality value of patients.

Do abrupt cryosphere events in High Mountain Asia indicate earlier tipping point than expected?

Tipping points of about 16 elements have been identified in Earth system,yet cryospheric tipping point of specific Alpine region has not been studied.Here we analyzed three tipping elements(mountain glacier,snow cover,and permafrost)identified in recent years,evidenced by the facts of frequent occurrence of abrupt massive collapse of glacier mass and the widespread thermakarst of permafrost.Since 2015,strikingly abrupt cryosphere events(ACEs)have been consistently observed over a large range of High Mountain Asia(HMA).Those events were un-precedentedly significant in history,leading to collapses of glaciers following by disconnection of glacier tongue from accumulation basin and recession of thermakarst towards higher elevation.Strong decreasing of snow depth in 2022 was also observed since 2021/2022 winter,coinciding with extreme warming of the year.The widespread high warming rates in the last two decades over HMA might have triggered above ACEs.The dynamic thresholds of ACEs depend largely on high temperature,especially extreme heat wave,for both glaciers and permafrost,closely related to meltwater as a key factor for reaching initial conditions of abrupt changes,suggesting HMA cryosphere is a tipping element under the global warming level of 1.1℃.The ACEs can cause tremendous damage to local ecosystem and socioeconomy,measures to mitigate risks should be taken when the tipping points are reached.

nfluences of superheat and cooling intensity on macrostructure and macrosegregation of duplex stainless steel studied by thermal simulation

The influences of superheat and cooling intensity on macrostructure and macrosegregation of one new kind duplex stainless steel(DSS)were studied.Thermal simulation equipment was applied to prepare samples,which could reproduce the industrial processes of DSS manufactured by a vertical continuous slab caster.Macrostructure and macrosegregation were analyzed using the digital single lens reflex and laser-induced breakdown spectroscope(LIBSOPA-200),respectively.The percentage of both chill zone and center equiaxed zone increases with the superheat decreasing,while that of the columnar zone decreases.There is only equiaxed grain existing as the superheat is 10 and 20℃.The lower the superheat is,the coarser the gain size is.High cooling intensity in mold could remarkably decrease the chill zone length and refine the grains in chill zone and center equiaxed zone.The influences of cooling intensity on macrosegregation are greater than those of superheat.The macrosegregation of Si,Mn and Cr is slightly dependent on superheat,while that of Cu,Mo and Ni changes greatly with superheat increasing.

Hot tearing susceptibility of Fe-20.96Cr-2.13Ni-0.15N-4.76Mn-0.01Mo duplex stainless steel

The hot tearing susceptibility of a Fe-20.96Cr-2.13Ni-0.15N-4.76Mn-0.01 Mo duplex stainless steel was investigated using method of constrained solidification shrinkage in one dimension.An apparatus for realtime measuring the contraction stress and temperature during solidification was developed,which can achieve the in-situ observation of melting and solidification and avoid the large temperature gradient of casting under the condition of pouring.The results show that the contraction stress increases significantly when the core temperature of casting reaches the liquidus temperature.The contraction stress is released when the core temperature of casting reaches 1456°C.At this temperature,the hot tearing susceptibility of duplex stainless steel is the largest.With decreasing the core temperature to 1363°C,the slope of contraction stress increases,which is related to the ferrite-to-austenite transformation.

In-situ measurement on air-water flux of CH_(4),CO_(2) and their carbon stable isotope in lakes of northeast Tibetan Plateau

Inland waters are important sources of greenhouse gases(GHGs)to the atmosphere that may partially offset the terrestrial carbon sink.However,GHG emissions from high altitude saline lakes on the Tibetan Plateau are currently poorly constrained.In this study,we measured methane(CH_(4))and carbon dioxide(CO_(2))concentrations and their carbon stable isotope(δ13C),and calculated diffusive water-to-air fluxes from two saline high-altitude lakes,Qinghai Lake and Hala Lake,located in northeast Tibetan Plateau in October 2020.The two lakes were mostly supersaturated in CH_(4)(89.8%-4623.9%sat)and acted as sources of CH_(4) to the atmosphere.Conversely,more than 96%investigated area of Qinghai Lake and all investigated area of Hala Lake was a sink of CO_(2).The average diffusive fluxes of CH_(4) and CO_(2) in the surface waters of Qinghai Lake were 34.51μmol m−2 d−1 and−1.29 mmol m−2 d−1,while diffusive fluxes of CH_(4) and CO_(2) in Hala Lake averaged 5.48μmol m−2 d−1 and−5.24 mmol m−2 d−1,respectively.Salinity(Sal),fluorescent dissolved organic matter(fDOM),temperature(Temp)and dissolved oxygen(DO)are key factors for diffusive CH_(4) and CO_(2) flux in Qinghai Lake and Hala Lake.CH_(4) diffusive fluxes across water-air interface from Qinghai Lake and Hala Lake were found to be significantly lower than other freshwater lakes,likely due to their saline nature.A simple isotope mixing model(Miller-Tans plots)revealed a distinctly different isotopic source values of CO_(2) and CH_(4) in Qinghai Lake and Hala Lake.The CH_(4) production pathway of Qinghai Lake was mainly by the acetate fermentation,while that of Hala Lake was mainly by the CO_(2) reduction.The results show that the continuous measurement can help capture the spatial variability of GHGs fluxes in saline lakes.

CH_(4) and C0_(2) observations from a melting high mountain glacier,Laohugou Glacier No.12

With global warming,glaciers in the high mountains of China are retreating rapidly.However,few data have been reported on whether greenhouse gases from these glaciers are released into the atmosphere or absorbed by glacial meltwater.In this study,we collected meltwater and ice samples from Laohugou Glacier No.12 in western China and measured CH_(4)and CO_(2)concentrations.Meltwater from the glacier terminus was continually sampled between 3 and 5 August 2020 to measure CH_(4)and CO_(2)concentrations.The results demonstrated that meltwater is a source of CH_(4)because the average saturations are over 100%.It could be con eluded that CH_(4)in the atmosphere can be released by glacial meltwater.However,the CO_(2)saturations are various,and CO_(2)fluxes exhibit positive(released CO_(2))or negative(absorbed CO_(2))values because the water and atmospheric conditions are variable.More importantly,the CH_(4)and CO_(2)concentrations were higher in meltwater samples from the glacier terminus than in samples from the surface ice(including an ice core)and a surface stream.Although the meltwater effect from the upper part of the glacier cannot be excluded,we speculated that subglacial drainage systems with an anaerobic environment may represent the CH_(4)source,but it needs to be further investigated in the future.However,high mountain glaciers are currently ignored in global carbon budgets,and the increased melting of glaciers with global warming may accelerate the absorption of much more CO_(2)and lead to the release of CH_(4).