Synthetic phenolic antioxidants(SPAs)and parabens,particularly the high-molecularweight(HMW)SPAs and long alkyl chain(LAC)parabens with higher environmental persistence and toxicities,are widely produced and applied w...Synthetic phenolic antioxidants(SPAs)and parabens,particularly the high-molecularweight(HMW)SPAs and long alkyl chain(LAC)parabens with higher environmental persistence and toxicities,are widely produced and applied worldwide.However,their occurrence and potential risks in aquatic environments remain largely unknown.This work investigated 11 HMW SPAs and 3 LAC parabens in the river and treated industrial wastewater samples along the Yangtze River,the largest river and most important source water in China.For convenience of comparison,6 short alkyl chain(SAC)parabens were also included.In 15 industrial wastewater treatment plant effluents(effluent-IWTPs)and 34 surface water monitoring sections along the river,19 out of 20 target compounds were detected with total concentrations(TCs)from 152.5 to 1955.5 ng/L and 141.3 to 1364.9 ng/L in effluent-IWTPs and surface water,respectively.HMW SPAs 1,3,5-tris-[(3,5-di–tert–butyl–4-hydroxyphenyl)methyl]-1,3,5-triazinane-2,4,6-trione(AO3114)and octadecyl 3-(3,5-di–tert–butyl–4-hydroxyphenyl)propionate(AO1076)were the dominant ones.HMWSPAs bis(3–tert–butyl–4–hydroxy-5-methylphenyl)propionate(AO245)and 4,4'-sulfanediylbis(2–tert–butyl–5-methylphenol)(AO-TBM6)and SAC parabens propylparaben(PrP)and butylparaben(BuP)posed medium to high potential ecological risks in 27 surface water monitoring sections.Additionally,AO-TBM6 also exhibited potential health risks in 2 out of 11 drinking water sources.Though the ecotoxicity data are very limited,the ubiquitous presence of the LAC parabens including hexylparaben(HeP)and octylparaben(OcP)in surface water should be of concern since these compounds usually exhibit stronger estrogen potencies than the SAC ones.Finally,kernel density analysis revealed that regulation of industrial discharges is necessary to mitigate the HMW SPA and paraben contamination.展开更多
BACKGROUND The objective of this study was to evaluate the use of combined parallax-free panoramic X-ray imaging during surgery by enabling the mobile C-arm with minimally invasive plate osteosynthesis(MIPO)in the man...BACKGROUND The objective of this study was to evaluate the use of combined parallax-free panoramic X-ray imaging during surgery by enabling the mobile C-arm with minimally invasive plate osteosynthesis(MIPO)in the management of proximal humeral shaft fractures.AIM To evaluate parallax-free panoramic X-ray images during surgery.METHODS A retrospective series of 17 proximal humeral shaft fractures were treated using combined parallax-free panoramic X-ray imaging during surgery by enabling the mobile C-arm with MIPO.The operating time and radiation exposure time were recorded,and early postoperative physical therapy and partial weight bearing were encouraged.Patients were followed at regular intervals and evaluated radiographically and clinically.RESULTS The mean operating time and radiation time were 73(range,49-95)minutes and 57(range:36-98)seconds,respectively.No complications occurred during the operation.All fractures healed at an average of 16.9(range:15-23)weeks.The average Constant-Murley score for all the patients was 89.5(range:75-100)points.None of the patients showed symptoms of vascular or nerve damage or wound infection.Three months after the operation,none of the patients developed subacromial impingement syndrome.No loosening or fracture of the implants occurred.The frontal and lateral radiographs showed good alignment.CONCLUSION We consider that MIPO with combined parallax-free panoramic X-ray imaging during surgery is an efficient method for treating proximal humeral shaft fractures,and could significantly reduce operative morbidity as well as lower the rate of intra-and postoperative complications.展开更多
AIM: To investigate the antifibrotic effects of bone morphogenetic protein-7 (BMP-7) on Schistosoma japonicum (S. japonicum )-induced hepatic fibrosis in BALB/C mice. METHODS: Sixty BALB/C mice were randomly divided i...AIM: To investigate the antifibrotic effects of bone morphogenetic protein-7 (BMP-7) on Schistosoma japonicum (S. japonicum )-induced hepatic fibrosis in BALB/C mice. METHODS: Sixty BALB/C mice were randomly divided into three groups, including a control group (group A, n = 20), model group (group B, n = 20) and BMP-7 treated group (group C, n = 20). The mice in group B and group C were abdominally infected with S. japonicum cercariae to induce a schistosomal hepatic fibrosis model. The mice in group C were administered human recombinant BMP-7. Liver samples were extracted from mice sacrificed at 9 and 15 wk after modeling. Hepatic histopathological changes were assessed using Masson's staining. Transforming growth factor-beta 1 (TGF-β1), alpha-smooth muscle actin (α-SMA), phosphorylated Smad2/3 (pSmad2/3) and Smad7 protein levels and localization were measured by Western blotting and immunohistochemistry, respectively, and their mRNA expressions were detected by reverse transcriptionpolymerase chain reaction (RT-PCR). RESULTS: The schistosomal hepatic fibrosis mouse model was successfully established, as the livers of mice in group B and group C showed varying degrees of typical schistosomal hepatopathologic changes such as egg granuloma and collagen deposition. The degree of collagen deposition in group C was higher than that in group A (week 9: 22.95±6.66vs 2.02±0.76; week 15: 12.84±4.36 vs 1.74±0.80; P<0.05), but significantly lower than that in group B (week 9: 22.95±6.66 vs 34.43±6.96; week 15: 12.84±4.36 vs 18.90±5.07;P<0.05) at both time points. According to immunohistochemistry data, the expressions of α-SMA, TGF-β1 and pSmad2/3 protein in group C were higher than those in group A (α-SMA: week 9: 21.24±5.73 vs 0.33±0.20; week 15: 12.42±4.88 vs 0.34±0.27; TGF-β1: week 9: 37.00±13.74 vs 3.73±2.14; week 15: 16.71±9.80 vs 3.08±2.35; pSmad2/3: week 9: 12.92±4.81 vs 0.83±0.48; week 15: 7.87±4.09 vs 0.90±0.45; P<0.05), but significantly lower than those in group B (α-SMA: week 9: 21.24±5.73 vs 34.39±5.74; week 15: 12.42±4.88 vs 25.90±7.01; TGF-β1: week 9: 37.00±13.74 vs 55.66±14.88; week 15: 16.71±9.80 vs 37.10±12.51; pSmad2/3: week 9: 12.92±4.81 vs 19.41±6.87; week 15: 7.87±4.09vs 13.00±4.98;P<0.05) at both time points; the expression of Smad7 protein in group B was higher than that in group A and group C at week 9 (8.46±3.95 vs 1.00±0.40 and 8.46±3.95 vs 0.77±0.42; P<0.05), while there were no differences in Smad7 expression between the three groups at week 15 (1.09±0.38 vs 0.97±0.42 vs 0.89±0.39; P>0.05). Although minor discrepancies were observed, the results of RT-PCR and Western blotting were mainly consistentwith the immunohistochemical results. CONCLUSION: Exogenous BMP-7 significantly decreased the degree of hepatic fibrosis in both the acute and chronic stages of hepato-schistosomiasis, and the regulatory mechanism may involve the TGF-β/Smad signaling pathway.展开更多
The large volume expansion and rapid capacity attenuation of tin-based electrodes are the main factors limiting their commercial application.The reasonable design of electrode material structure is particularly import...The large volume expansion and rapid capacity attenuation of tin-based electrodes are the main factors limiting their commercial application.The reasonable design of electrode material structure is particularly important for improving its electrochemical performance.Herein,phosphorus-modified graphene encapsulated Sn_(6)O_(4)(OH)_(4)nanoparticles composite(P-Sn_(6)O_(4)(OH)_(4)@RGO)with crystalline-amorphous heterostructure has been successfully designed and prepared.The design of crystalline-amorphous structure has largely enhanced the active sites,and the construction of a graphene encapsulation structure has greatly alleviated volume expansion.Notably,P-Sn_(6)O_(4)(OH)_(4)@RGO obtained an excellent high-rate longterm cycling performance for lithium-ion batteries anode,reaching a high specific capacity of 970 m Ah/g at 1.0 A/g after 1450 cycles.This work demonstrates that restructuring the electrode material's structure and phase through phosphorus modification can effectively improve the electrochemical performance of tin-based electrode materials.展开更多
In nanofluid minimum quantity lubrication(NMQL)milling of aviation aluminum alloy,it is the bottleneck problem to adjust the position parameters(target distance,incidence angle,and elevation angle)of the nozzle to imp...In nanofluid minimum quantity lubrication(NMQL)milling of aviation aluminum alloy,it is the bottleneck problem to adjust the position parameters(target distance,incidence angle,and elevation angle)of the nozzle to improve the surface roughness of milling,which has large and uncontrollable errors.In this paper,the influence law of milling cutter speed,helical angle,and cavity shape on the flow field around the milling cutter was studied,and the optimal nozzle profile parameters were obtained.Using 7050 aluminum alloy as the workpiece material,the milling experiment of the NMQL cavity was conducted by utilizing cottonseed oil-based Al2 O3 nanofluid.Results show that the high velocity of the surrounding air flow field and the strong gas barrier could be attributed to high rotating velocities of the milling cutter.The incidence angle of the nozzle was consistent with the helical angle of the milling cutter,the target distance was appropriate at 25–30 mm,and the elevation angle was suitable at 60°–65°.The range and variance analyses of the signal-to-noise ratio of milling force and roughness were performed,and the chip morphology was observed and analyzed.The results show that the optimal combination of nozzle position parameters was the target distance of 30 mm,the incidence angle of 35°,and the elevation angle of 60°.Among these parameters,target distance had the largest impact on cutting performance with a contribution rate of more than 55%,followed by incidence angle and elevation contribution rate.Analysis by orthogonal experiment revealed that the nozzle position parameters were appropriate,and Ra(0.087 lm)was reduced by 30.4%from the maximum value(0.125 lm).Moreover,Rsm(0.05 mm)was minimum,which was 36%lower than that of the seventh group(Rsm=0.078 mm).展开更多
Aluminum alloy is the main structural material of aircraft,launch vehicle,spaceship,and space station and is processed by milling.However,tool wear and vibration are the bottlenecks in the milling process of aviation ...Aluminum alloy is the main structural material of aircraft,launch vehicle,spaceship,and space station and is processed by milling.However,tool wear and vibration are the bottlenecks in the milling process of aviation aluminum alloy.The machining accuracy and surface quality of aluminum alloy milling depend on the cutting parameters,material mechanical properties,machine tools,and other parameters.In particular,milling force is the crucial factor to determine material removal and workpiece surface integrity.However,establishing the prediction model of milling force is important and difficult because milling force is the result of multiparameter coupling of process system.The research progress of cutting force model is reviewed from three modeling methods:empirical model,finite element simulation,and instantaneous milling force model.The problems of cutting force modeling are also determined.In view of these problems,the future work direction is proposed in the following four aspects:(1)high-speed milling is adopted for the thin-walled structure of large aviation with large cutting depth,which easily produces high residual stress.The residual stress should be analyzed under this particular condition.(2)Multiple factors(e.g.,eccentric swing milling parameters,lubrication conditions,tools,tool and workpiece deformation,and size effect)should be considered comprehensively when modeling instantaneous milling forces,especially for micro milling and complex surface machining.(3)The database of milling force model,including the corresponding workpiece materials,working condition,cutting tools(geometric figures and coatings),and other parameters,should be established.(4)The effect of chatter on the prediction accuracy of milling force cannot be ignored in thin-walled workpiece milling.(5)The cutting force of aviation aluminum alloy milling under the condition of minimum quantity lubrication(mql)and nanofluid mql should be predicted.展开更多
The method for detecting N-nitrosodimethylamine （NDMA） in drinking water using ultra performance liquid chromatography （UPLC） coupled with tandem mass spectrometry （MS/MS） was improved by optimizing the clean-up...The method for detecting N-nitrosodimethylamine （NDMA） in drinking water using ultra performance liquid chromatography （UPLC） coupled with tandem mass spectrometry （MS/MS） was improved by optimizing the clean-up procedure to remove the matrix interference in pretreatment process, and was then applied to a survey of NDMA in both raw and finished water samples from five water treatment plants in South China. The NDMA concentrations ranged from 4.7 to 15.1 ng/L in raw water samples, and from 4.68 to 46.9 ng/L in finished water. The NDMA concentration in raw water was found to be related with nitrite concentration, and during the treatment, the NDMA concentration increased following ozonation but decreased after subsequent activated carbon treatment.展开更多
BACKGROUND Type 2 diabetes mellitus(T2DM)is significantly increasing worldwide,and the incidence of its complications is also on the rise.One of the main complications of T2DM is diabetic kidney disease(DKD).The glome...BACKGROUND Type 2 diabetes mellitus(T2DM)is significantly increasing worldwide,and the incidence of its complications is also on the rise.One of the main complications of T2DM is diabetic kidney disease(DKD).The glomerular filtration rate(GFR)and urinary albumin creatinine ratio(UACR)increase in the early stage.As the disease progresses,UACR continue to rise and GFR begins to decline until endstage renal disease appears.At the same time,DKD will also increase the incidence and mortality of cardiovascular and cerebrovascular diseases.At present,the pathogenesis of DKD is not very clear.Therefore,exploration of the pathogenesis of DKD to find a treatment approach,so as to delay the development of DKD,is essential to improve the prognosis of DKD.AIM To detect the expression of tenascin-C(TNC)in the serum of T2DM patients,observe the content of TNC in the glomerulus of DKD rats,and detect the expression of TNC on inflammatory and fibrotic factors in rat mesangial cells(RMCs)cultured under high glucose condition,in order to explore the specific molecular mechanism of TNC in DKD and bring a new direction for the treatment of DKD.METHODS The expression level of TNC in the serum of diabetic patients was detected by enzyme-linked immunosorbent assay(ELISA),the protein expression level of TNC in the glomerular area of DKD rats was detected by immunohistochemistry,and the expression level of TNC in the rat serum was detected by ELISA.Rat glomerular mesangial cells were cultured.Following high glucose stimulation,the expression levels of related proteins and mRNA were detected by Western blot and polymerase chain reaction,respectively.RESULTS ELISA results revealed an increase in the serum TNC level in patients with T2DM.Increasing UACR and hypertension significantly increased the expression of TNC(P<0.05).TNC expression was positively correlated with glycosylated haemoglobin(HbA1c)level,body mass index,systolic blood pressure,and UACR(P<0.05).Immunohistochemical staining showed that TNC expression in the glomeruli of rats with streptozotocin-induced diabetes was significantly increased compared with normal controls(P<0.05).Compared with normal rats,serum level of TNC in diabetic rats was significantly increased(P<0.05),which was positively correlated with urea nitrogen and urinary creatinine(P<0.05).The levels of TNC,Toll-like receptor-4(TLR4),phosphorylated nuclear factor-κB p65 protein(Ser536)(p-NF-κB p65),and miR-155-5p were increased in RMCs treated with high glucose(P<0.05).The level of TNC protein peaked 24 h after high glucose stimulation(P<0.05).After TNC knockdown,the levels of TLR4,p-NF-κB p65,miR-155-5p,connective tissue growth factor(CTGF),and fibronectin(FN)were decreased,revealing that TNC regulated miR-155-5p expression through the TLR4/NF-κB p65 pathway,thereby regulating inflammation(NF-κB p65)and fibrosis(CTGF and FN)in individuals with DKD.In addition,metformin treatment may relive the processes of inflammation and fibrosis in individuals with DKD by reducing the levels of the TNC,p-NF-κB p65,CTGF,and FN proteins.CONCLUSION TNC can promote the occurrence and development of DKD.Interfering with the TNC/TLR4/NF-κB p65/miR-155-5p pathway may become a new target for DKD treatment.展开更多
Background:This study aimed to investigate the effects of oral administration of Enterococcus faecium NCIMB10415(E.faecium)on intestinal development,immunological parameters and gut microbiota of neonatal piglets chal...Background:This study aimed to investigate the effects of oral administration of Enterococcus faecium NCIMB10415(E.faecium)on intestinal development,immunological parameters and gut microbiota of neonatal piglets challenged with enterotoxigenic Escherichia coli K88(ETEC).A total of 961-day-old sow-reared piglets were randomly assigned to 2 groups,with 48 piglets in each group.The piglets were from 16 litters(6 piglets each litter),and 3 piglets each litter were allocated to the E.faecium-supplemented(PRO)group,while the other 3 piglets were allocated to the control(CON)group.After colostrum intake,piglets in the PRO group were orally administrated with 3×10~9 CFU E.faecium per day for a period of one week.On day 8,one piglet per litter from each group was challenged(CON+ETEC,PRO+ETEC)or not(CON-ETEC,PRO-ETEC)with ETEC in a 2×2 factorial arrangement of treatments.On day 10(2 days after challenge),blood and tissue samples were obtained from piglets.Results:Before ETEC challenge,there were no significant differences for the average daily gain(ADG)and fecal score between the two groups of piglets.After ETEC challenge,the challenged piglets had greater fecal score compared to the non-challenged piglets,whereas E.faecium administration was able to decrease the fecal score.Piglets challenged with ETEC had shorter villous height,deeper crypt depth,and reduced number of goblet cells in the jejunum and decreased m RNA abundance of claudin-1 in the ileum,whereas increased the percentage of lymphocytes,concentrations of IL-1βin the plasma and TNF-αin the ileal mucosa,as well as increased the m RNA abundances of innate immunity-related genes in the ileum tissue.These deleterious effects caused by ETEC were partly alleviated by feeding E.faecium.In addition,piglets in PRO-ETEC group had decreased the percentage of CD8^+T cells of the peripheral blood when compared to those in CON-ETEC group.Moreover,E.faecium administration increased Verrucomicrobia at phylum level and decreased Bilophila at genus level.Conclusions:These results suggest that oral administration of E.faecium alleviated the intestinal injury and diarrhea severity of neonatal piglets challenged by ETEC,partly through improving the intestinal microbiota and immune response.This offers a potential strategy of dietary intervention against intestinal impairment by ETEC in neonatal piglets.展开更多
Metal cutting fluids(MCFs)under flood conditions do not meet the urgent needs of reducing carbon emission.Biolubricant-based minimum quantity lubrication(MQL)is an effective alternative to flood lubrication.However,pn...Metal cutting fluids(MCFs)under flood conditions do not meet the urgent needs of reducing carbon emission.Biolubricant-based minimum quantity lubrication(MQL)is an effective alternative to flood lubrication.However,pneumatic atomization MQL has poor atomization properties,which is detrimental to occupational health.Therefore,electrostatic atomization MQL requires preliminary exploratory studies.However,systematic reviews are lacking in terms of capturing the current research status and development direction of this technology.This study aims to provide a comprehensive review and critical assessment of the existing understanding of electrostatic atomization MQL.This research can be used by scientists to gain insights into the action mechanism,theoretical basis,machining performance,and development direction of this technology.First,the critical equipment,eco-friendly atomization media(biolubricants),and empowering mechanisms of electrostatic atomization MQL are presented.Second,the advanced lubrication and heat transfer mechanisms of biolubricants are revealed by quantitatively comparing MQL with MCF-based wet machining.Third,the distinctive wetting and infiltration mechanisms of electrostatic atomization MQL,combined with its unique empowering mechanism and atomization method,are compared with those of pneumatic atomization MQL.Previous experiments have shown that electrostatic atomization MQL can reduce tool wear by 42.4%in metal cutting and improve the machined surface Ra by 47%compared with pneumatic atomization MQL.Finally,future development directions,including the improvement of the coordination parameters and equipment integration aspects,are proposed.展开更多
Minimum quantity Lubrication(MQL)is a sustainable lubrication system that is famous in many machining systems.It involve the spray of an infinitesimal amount of mist-like lubricants during machining processes.The MQL ...Minimum quantity Lubrication(MQL)is a sustainable lubrication system that is famous in many machining systems.It involve the spray of an infinitesimal amount of mist-like lubricants during machining processes.The MQL system is affirmed to exhibit an excellent machining performance,and it is highly economical.The nanofluids are understood to exhibit excellent lubricity and heat evacuation capability,compared to pure oil-based MQL system.Studies have shown that the surface quality and amount of energy expended in the grinding operations can be reduced considerably due to the positive effect of these nanofluids.This work presents an experimental study on the tribological performance of SiO_(2)nanofluid during grinding of Si_(3)N_(4)ceramic.The effect different grinding modes and lubrication systems during the grinding operation was also analyzed.Different concentrations of the SiO_(2)nanofluid was manufactured using canola,corn and sunflower oils.The quantitative evaluation of the grinding process was done based on the amount of grinding forces,specific grinding energy,frictional coefficient,and surface integrity.It was found that the canola oil exhibits optimal lubrication performance compared to corn oil,sunflower oil,and traditional lubrication systems.Additionally,the introduction of ultrasonic vibrations with the SiO_(2)nanofluid in MQL system was found to reduce the specific grinding energy,normal grinding forces,tangential grinding forces,and surface roughness by 65%,57%,65%,and 18%respectively.Finally,regression analysis was used to obtain an optimum parameter combinations.The observations from this work will aid the smooth transition towards ecofriendly and sustainable machining of engineering ceramics.展开更多
Recently, the rarely reported tet(31) tetracycline resistance determinant was commonly found in Aeromonas salmonicida, Gallibacterium anatis, and Oblitimonas alkaliphila isolated from farming animals and related envir...Recently, the rarely reported tet(31) tetracycline resistance determinant was commonly found in Aeromonas salmonicida, Gallibacterium anatis, and Oblitimonas alkaliphila isolated from farming animals and related environment. However, its distribution in other bacteria and potential molecular dissemination mechanism in environment are still unknown. The purpose of this study was to investigate the potential mechanism underlying dissemination of tet(31) by analysing the tet(31)-carrying fragments in A. caviae strains isolated from an aerobic biofilm reactor treating oxytetracycline bearing wastewater. Twenty-three A. caviae strains were screened for the tet(31) gene by polymerase chain reaction(PCR). Three strains(two harbouring tet(31), one not) were subjected to whole genome sequencing using the PacBio RSII platform. Seventeen A. caviae strains carried the tet(31) gene and exhibited high resistance levels to oxytetracycline with minimum inhibitory concentrations(MICs)ranging from 256 to 512 mg/L. tet(31) was comprised of the transposon Tn6432 on the chromosome of A. caviae, and Tn6432 was also found in 15 additional tet(31)-positive A. caviae isolates by PCR. More important, Tn6432 was located on an integrative conjugative element(ICE)-like element, which could mediate the dissemination of the tet(31)-carrying transposon Tn6432 between bacteria. Comparative analysis demonstrated that Tn6432 homologs with the structure ISCR2-ΔphzF-tetR(31)-tet(31)-ΔglmM-sul2 were also carried by A. salmonicida, G. anatis, and O. alkaliphila, suggesting that this transposon can be transferred between species and even genera. This work provides the first report on the identification of the tet(31) gene in A. caviae, and will be helpful in exploring the dissemination mechanisms of tet(31) in water environment.展开更多
The formation of toxic nitrogenous disinfection byproducts （N-DBPs）, such as nitrosamines, halonitromethanes and haloacetonitriles, from reactions between chlorine/chloramine and dissolved organic nitrogen in drinki...The formation of toxic nitrogenous disinfection byproducts （N-DBPs）, such as nitrosamines, halonitromethanes and haloacetonitriles, from reactions between chlorine/chloramine and dissolved organic nitrogen in drinking water has caused great concern with regarding public health. This study revealed the occurrence of 17 aliphatic amines, some of which have been confirmed to be the precursors of N-DBPs, in source water across China. A sensitive method based on benzenesulfonyl chloride derivatization and liquid-liquid extraction followed by GC-MS analysis was established for the simultaneous analysis of the selected amines in aqueous samples. In total, 37 source water samples from the capital cities of 20 provinces were collected for the survey. Among the 17 amines, 14 were detected with an average frequency of detection of 36%. The most relevant amines in terms of frequency and maximum concentrations detected were dimethylamine （100%, 24.82 μg/L）, methylamine （78%, 0.92 μg/L）, N-methylethylamine （70%, 8.84 μg/L）, propylamine （59%, 10.69 μg/L）, diethylamine （54%, 3.76μg/L）, N-methylbutylamine （35%, 3.07 μg/L）, N-ethylpropylamine （35%, 0.52μg/L）, and piperidine （32%, 2.35 μg/L）. This is the first large scale survey of the aliphatic amines occurrence in source water in the world. The wide presence of nitrosamine precursors like dimethylamine, N-methylethylamine and diethylamine, and the precursors of haloacetonitriles and halonitromethanes like methylamine and propylamine suggests that better source water management is required to ensure the safety of drinking water.展开更多
The double minimum creep,characterized by two creep rate minima,in Co-based superalloy is investigated using a phase-field model coupled with a crystal plasticity model.The constitutive modeling,based on the dislocati...The double minimum creep,characterized by two creep rate minima,in Co-based superalloy is investigated using a phase-field model coupled with a crystal plasticity model.The constitutive modeling,based on the dislocation slip theory considering dislocation interaction,is applied to simulate microstructural evolution and deformation behavior.Rafting process commences at the beginning of creep until the global minimum of creep rate is reached,demonstrating a strengthening effect from N-type rafts under compressive creep.The high shear strain rate of(111)[011]slip system in the intersections of horizontal and verticalγchannels leads to a slight increase of creep rate after the first local minimum.The evolution of stress field shows that the softening effect is the combined effect of the increase of resolved shear stress and the decrease of hardening stress in the intersections.Further,these changes in stress are primarily caused by the dislocation annihilation and the inhomogeneous plastic deformation.This study indicates that the intermediate local softening stage during creep may be eliminated if the initial inter-distance betweenγ’precipitates is decreased.展开更多
In order to promote the thermostability of a-diimine nickel complex by ligand backbone structure,a series of α-diimine nickel complexes with substituents on acenaphthequinone backbone were synthesized and used as cat...In order to promote the thermostability of a-diimine nickel complex by ligand backbone structure,a series of α-diimine nickel complexes with substituents on acenaphthequinone backbone were synthesized and used as catalysts for ethylene polymerization.When the hydroxyethyl phenoxyl group was introduced to the acenaphthequinone-backbone,the thermal stability and activity of the catalyst could be significantly improved.The catalytic activity of complex C2[5-(4-(2-hydroxyethyl)phenoxyl)-N,N-bis(2,6-diisopropyl)acenaphthylene-1,2-diimine]nickel(Ⅱ)dibromide with isopropyl substituents on N-aryl reached 8.2×10^6g/(molNi·h)at 70℃and 2 MPa.The activity of[5-(4-(2-hydroxyethyl)phenoxyl)-N,N-bis(2,6-dibenzhydryl-4-menthylphenyl)acenaphthylene-1,2-diimine]nickel(Ⅱ)dibromide(C3)still maintained at 6.7×10^5 g/(molNi·h)at 120℃.Compared with C3 containing bulky dibenzhydryl substituents,the activity of C2 was sensitive to the change of the polymerization pressure.However,the polyethylenes obtained from complex C3 had lower branching density.Meanwhile,the molecular weight could reach 971 kg/mol,which is almost 5 times as much as that of the polyethylene obtained from complex C2.展开更多
The influence of the tool profiles on the thermo-mechanical interaction between AA6061-T6 workpiece and tool during friction stir welding was investigated. A customized experimental setup was employed to measure the f...The influence of the tool profiles on the thermo-mechanical interaction between AA6061-T6 workpiece and tool during friction stir welding was investigated. A customized experimental setup was employed to measure the feature points temperature and tool spindle torque in the process of FSW. Microstructure and tensile properties of stir zone (SZ) were characterized. Results indicate that the shoulder and pin geometries were responsible for the heat generation, tool torque variation at the plunging stage as well as the cross section contour of SZ, respectively. Finer grains in SZ resulted from flutes on shoulder and grooves on pin. Flat faces on the pin resulted in inhomogeneous grain size. Weld with higher 0.2% yield strength of 173 MPa was obtained by using the cylindrical pin tool while higher elongation weld of 32.0% was produced with triflat threaded pin tool.展开更多
Taste and odor （T/O） in drinking water often cause consumer complaints and are thus regulated in many countries. However, people in different regions may exhibit different sensitivities toward WO. This study propose...Taste and odor （T/O） in drinking water often cause consumer complaints and are thus regulated in many countries. However, people in different regions may exhibit different sensitivities toward WO. This study proposed a method to determine the regional drinking water odorant regulation goals （ORGs） based on the odor sensitivity distribution of the local population. The distribution of odor sensitivity to 2-methylisobomeol （2-MIB） by the local population in Beijing, China was revealed by using a normal distribution function/model to describe the odor complaint response to a 2-MIB episode in 2005, and a 2-MIB concentration of 12.9 ng/L and FPA （flavor profile analysis） intensity of 2.5 was found to be the critical point to cause odor complaints. Thus the Beijing ORG for 2-MIB was determined to be 12.9 ng/L. Based on the assumption that the local FPA panel can represent the local population in terms of sensitivity to odor, and that the critical FPA intensity causing odor complaints was 2.5, this study tried to determine the ORGs for seven other cities of China by performing FPA tests using an FPA panel from the corresponding city. ORG values between 12.9 and 31.6 ng/L were determined, showing that a unified ORG may not be suitable for drinking water odor regulations. This study presents a novel approach for setting drinking water odor regulations.展开更多
The tet C gene has been found to be one of the most widely distributed tetracycline resistance( tet) genes in various environmental niches, but the detailed dissemination mechanisms are still largely unknown. In the p...The tet C gene has been found to be one of the most widely distributed tetracycline resistance( tet) genes in various environmental niches, but the detailed dissemination mechanisms are still largely unknown. In the present study, 11 tet C-containing Aeromonas media strains were isolated from an aerobic biofilm reactor under oxytetracycline stresses, and the genome of one strain was sequenced using the Pac Bio RSII sequencing approach to reveal the genetic environment of tet C. The tet C gene was carried by an IS 26 composite transposon, named Tn 6434. The tet C-carrying Tn 6434 structure was detected in all of the A. media strains either in a novel plasmid p Aeme2( n = 9) or other DNA molecules( n = 2) by PCR screening. The NCBI database searching result shows that this structure was also present in the plasmids or chromosomes of other 13 genera, indicating the transferability of Tn 6434. Inverse PCR and sequencing confirmed that Tn 6434 can form a circular intermediate and is able to incorporate into a preexisting IS 26 element, suggesting that Tn 6434 might be responsible for the dissemination of tet C between different DNA molecules. This study will be helpful in uncovering the spread mechanism of tet genes in water environments.展开更多
A novel amine-modified pillar[5]arene bonded porous silica adsorbent(DETA-P5S)was designed to be applied to dynamic CO_(2)adsorption and selective separation of CO_(2)over N_(2)and CH_(4)gases mixture.The results demo...A novel amine-modified pillar[5]arene bonded porous silica adsorbent(DETA-P5S)was designed to be applied to dynamic CO_(2)adsorption and selective separation of CO_(2)over N_(2)and CH_(4)gases mixture.The results demonstrated that reasonable introduction of DETA into the BE-P5 bonded silica support has sig nificantly increased the adsorption capacity of CO_(2).The DETA-P5S has the optimal adsorption capacity of 9.1 mmol/g with 5 vol%CO_(2)at 40℃.The main reason of this increased capacity could be attributed to the enhanced CO_(2)diffusion into porous adsorbent for its better dispersion in the pores of amine pillar[5]arene cavity and active site of DETA.Furthermore,the dynamic saturation adsorption capacitie of DETA-P5S were 7.11(0.37)and 6.18(0.44)mmol/g for CO_(2)/N_(2)and CO_(2)/CH_(4),respectively,both the ga mixtures showed high separation selectivity.Simultaneously,the DETA-P5S can maintain outstanding CO_(2)adsorption capacity after fifteen regeneration cycles.Consequently,the designed DETA-P5S could serve a a promising adsorbent for CO_(2)capture and storage.展开更多
基金supported by the National Key Research and Development Program of China(Nos.2021YFC3200801 and 2021YFC3200804).
文摘Synthetic phenolic antioxidants(SPAs)and parabens,particularly the high-molecularweight(HMW)SPAs and long alkyl chain(LAC)parabens with higher environmental persistence and toxicities,are widely produced and applied worldwide.However,their occurrence and potential risks in aquatic environments remain largely unknown.This work investigated 11 HMW SPAs and 3 LAC parabens in the river and treated industrial wastewater samples along the Yangtze River,the largest river and most important source water in China.For convenience of comparison,6 short alkyl chain(SAC)parabens were also included.In 15 industrial wastewater treatment plant effluents(effluent-IWTPs)and 34 surface water monitoring sections along the river,19 out of 20 target compounds were detected with total concentrations(TCs)from 152.5 to 1955.5 ng/L and 141.3 to 1364.9 ng/L in effluent-IWTPs and surface water,respectively.HMW SPAs 1,3,5-tris-[(3,5-di–tert–butyl–4-hydroxyphenyl)methyl]-1,3,5-triazinane-2,4,6-trione(AO3114)and octadecyl 3-(3,5-di–tert–butyl–4-hydroxyphenyl)propionate(AO1076)were the dominant ones.HMWSPAs bis(3–tert–butyl–4–hydroxy-5-methylphenyl)propionate(AO245)and 4,4'-sulfanediylbis(2–tert–butyl–5-methylphenol)(AO-TBM6)and SAC parabens propylparaben(PrP)and butylparaben(BuP)posed medium to high potential ecological risks in 27 surface water monitoring sections.Additionally,AO-TBM6 also exhibited potential health risks in 2 out of 11 drinking water sources.Though the ecotoxicity data are very limited,the ubiquitous presence of the LAC parabens including hexylparaben(HeP)and octylparaben(OcP)in surface water should be of concern since these compounds usually exhibit stronger estrogen potencies than the SAC ones.Finally,kernel density analysis revealed that regulation of industrial discharges is necessary to mitigate the HMW SPA and paraben contamination.
基金Supported by Wuhu Municipal Science and Technology Bureau of Anhui Province,No.2022cg43.
文摘BACKGROUND The objective of this study was to evaluate the use of combined parallax-free panoramic X-ray imaging during surgery by enabling the mobile C-arm with minimally invasive plate osteosynthesis(MIPO)in the management of proximal humeral shaft fractures.AIM To evaluate parallax-free panoramic X-ray images during surgery.METHODS A retrospective series of 17 proximal humeral shaft fractures were treated using combined parallax-free panoramic X-ray imaging during surgery by enabling the mobile C-arm with MIPO.The operating time and radiation exposure time were recorded,and early postoperative physical therapy and partial weight bearing were encouraged.Patients were followed at regular intervals and evaluated radiographically and clinically.RESULTS The mean operating time and radiation time were 73(range,49-95)minutes and 57(range:36-98)seconds,respectively.No complications occurred during the operation.All fractures healed at an average of 16.9(range:15-23)weeks.The average Constant-Murley score for all the patients was 89.5(range:75-100)points.None of the patients showed symptoms of vascular or nerve damage or wound infection.Three months after the operation,none of the patients developed subacromial impingement syndrome.No loosening or fracture of the implants occurred.The frontal and lateral radiographs showed good alignment.CONCLUSION We consider that MIPO with combined parallax-free panoramic X-ray imaging during surgery is an efficient method for treating proximal humeral shaft fractures,and could significantly reduce operative morbidity as well as lower the rate of intra-and postoperative complications.
文摘AIM: To investigate the antifibrotic effects of bone morphogenetic protein-7 (BMP-7) on Schistosoma japonicum (S. japonicum )-induced hepatic fibrosis in BALB/C mice. METHODS: Sixty BALB/C mice were randomly divided into three groups, including a control group (group A, n = 20), model group (group B, n = 20) and BMP-7 treated group (group C, n = 20). The mice in group B and group C were abdominally infected with S. japonicum cercariae to induce a schistosomal hepatic fibrosis model. The mice in group C were administered human recombinant BMP-7. Liver samples were extracted from mice sacrificed at 9 and 15 wk after modeling. Hepatic histopathological changes were assessed using Masson's staining. Transforming growth factor-beta 1 (TGF-β1), alpha-smooth muscle actin (α-SMA), phosphorylated Smad2/3 (pSmad2/3) and Smad7 protein levels and localization were measured by Western blotting and immunohistochemistry, respectively, and their mRNA expressions were detected by reverse transcriptionpolymerase chain reaction (RT-PCR). RESULTS: The schistosomal hepatic fibrosis mouse model was successfully established, as the livers of mice in group B and group C showed varying degrees of typical schistosomal hepatopathologic changes such as egg granuloma and collagen deposition. The degree of collagen deposition in group C was higher than that in group A (week 9: 22.95±6.66vs 2.02±0.76; week 15: 12.84±4.36 vs 1.74±0.80; P<0.05), but significantly lower than that in group B (week 9: 22.95±6.66 vs 34.43±6.96; week 15: 12.84±4.36 vs 18.90±5.07;P<0.05) at both time points. According to immunohistochemistry data, the expressions of α-SMA, TGF-β1 and pSmad2/3 protein in group C were higher than those in group A (α-SMA: week 9: 21.24±5.73 vs 0.33±0.20; week 15: 12.42±4.88 vs 0.34±0.27; TGF-β1: week 9: 37.00±13.74 vs 3.73±2.14; week 15: 16.71±9.80 vs 3.08±2.35; pSmad2/3: week 9: 12.92±4.81 vs 0.83±0.48; week 15: 7.87±4.09 vs 0.90±0.45; P<0.05), but significantly lower than those in group B (α-SMA: week 9: 21.24±5.73 vs 34.39±5.74; week 15: 12.42±4.88 vs 25.90±7.01; TGF-β1: week 9: 37.00±13.74 vs 55.66±14.88; week 15: 16.71±9.80 vs 37.10±12.51; pSmad2/3: week 9: 12.92±4.81 vs 19.41±6.87; week 15: 7.87±4.09vs 13.00±4.98;P<0.05) at both time points; the expression of Smad7 protein in group B was higher than that in group A and group C at week 9 (8.46±3.95 vs 1.00±0.40 and 8.46±3.95 vs 0.77±0.42; P<0.05), while there were no differences in Smad7 expression between the three groups at week 15 (1.09±0.38 vs 0.97±0.42 vs 0.89±0.39; P>0.05). Although minor discrepancies were observed, the results of RT-PCR and Western blotting were mainly consistentwith the immunohistochemical results. CONCLUSION: Exogenous BMP-7 significantly decreased the degree of hepatic fibrosis in both the acute and chronic stages of hepato-schistosomiasis, and the regulatory mechanism may involve the TGF-β/Smad signaling pathway.
基金supported by the Natural Science Foundation of Shandong Province(Nos.ZR2024QE450,ZR2024QB302 and ZR2024QB004)the Taishan Scholars and Young Experts Program of Shandong Province(No.tsqn202211249)Research Program of Qilu Institute of Technology(Nos.QIT 23TP019,QIT23TP010 and QIT24NN007)。
文摘The large volume expansion and rapid capacity attenuation of tin-based electrodes are the main factors limiting their commercial application.The reasonable design of electrode material structure is particularly important for improving its electrochemical performance.Herein,phosphorus-modified graphene encapsulated Sn_(6)O_(4)(OH)_(4)nanoparticles composite(P-Sn_(6)O_(4)(OH)_(4)@RGO)with crystalline-amorphous heterostructure has been successfully designed and prepared.The design of crystalline-amorphous structure has largely enhanced the active sites,and the construction of a graphene encapsulation structure has greatly alleviated volume expansion.Notably,P-Sn_(6)O_(4)(OH)_(4)@RGO obtained an excellent high-rate longterm cycling performance for lithium-ion batteries anode,reaching a high specific capacity of 970 m Ah/g at 1.0 A/g after 1450 cycles.This work demonstrates that restructuring the electrode material's structure and phase through phosphorus modification can effectively improve the electrochemical performance of tin-based electrode materials.
基金the National Natural Science Foundation of China(Nos.51975305,51806112and 51905289)the Major Research Project of Shandong Province of China(Nos.2019GGX104040 and 2019GSF108236)+2 种基金the Shandong Provincial Natural Science Foundation of China(No.ZR2019PEE008)Major Science and Technology Innovation Engineering Projects of Shandong Province of China(No.2019JZZY020111)Applied Basic Research Youth Project of Qingdao Science and Technology Plan of China(No.19-6-2-63-cg)。
文摘In nanofluid minimum quantity lubrication(NMQL)milling of aviation aluminum alloy,it is the bottleneck problem to adjust the position parameters(target distance,incidence angle,and elevation angle)of the nozzle to improve the surface roughness of milling,which has large and uncontrollable errors.In this paper,the influence law of milling cutter speed,helical angle,and cavity shape on the flow field around the milling cutter was studied,and the optimal nozzle profile parameters were obtained.Using 7050 aluminum alloy as the workpiece material,the milling experiment of the NMQL cavity was conducted by utilizing cottonseed oil-based Al2 O3 nanofluid.Results show that the high velocity of the surrounding air flow field and the strong gas barrier could be attributed to high rotating velocities of the milling cutter.The incidence angle of the nozzle was consistent with the helical angle of the milling cutter,the target distance was appropriate at 25–30 mm,and the elevation angle was suitable at 60°–65°.The range and variance analyses of the signal-to-noise ratio of milling force and roughness were performed,and the chip morphology was observed and analyzed.The results show that the optimal combination of nozzle position parameters was the target distance of 30 mm,the incidence angle of 35°,and the elevation angle of 60°.Among these parameters,target distance had the largest impact on cutting performance with a contribution rate of more than 55%,followed by incidence angle and elevation contribution rate.Analysis by orthogonal experiment revealed that the nozzle position parameters were appropriate,and Ra(0.087 lm)was reduced by 30.4%from the maximum value(0.125 lm).Moreover,Rsm(0.05 mm)was minimum,which was 36%lower than that of the seventh group(Rsm=0.078 mm).
基金Suppo rted by National Natural Science Foundation of China(Grant Nos.51975305,51905289)Major Research Project of Shandong Province of China(Grant Nos.2019GGX104040,2019GSF108236)+2 种基金Major Science and Technology Innovation Engineering Projects of Shandong Province of China(Grant No.2019JZZY020111)the Natural Scie nce Foundation of Shandong Province(Grant Nos.ZR2020KE027 and ZR2020ME158)Applied Basic Research Youth Project of Qingdao Science and Technology Plan of China(Grant No.19-6-2-63-cg).
文摘Aluminum alloy is the main structural material of aircraft,launch vehicle,spaceship,and space station and is processed by milling.However,tool wear and vibration are the bottlenecks in the milling process of aviation aluminum alloy.The machining accuracy and surface quality of aluminum alloy milling depend on the cutting parameters,material mechanical properties,machine tools,and other parameters.In particular,milling force is the crucial factor to determine material removal and workpiece surface integrity.However,establishing the prediction model of milling force is important and difficult because milling force is the result of multiparameter coupling of process system.The research progress of cutting force model is reviewed from three modeling methods:empirical model,finite element simulation,and instantaneous milling force model.The problems of cutting force modeling are also determined.In view of these problems,the future work direction is proposed in the following four aspects:(1)high-speed milling is adopted for the thin-walled structure of large aviation with large cutting depth,which easily produces high residual stress.The residual stress should be analyzed under this particular condition.(2)Multiple factors(e.g.,eccentric swing milling parameters,lubrication conditions,tools,tool and workpiece deformation,and size effect)should be considered comprehensively when modeling instantaneous milling forces,especially for micro milling and complex surface machining.(3)The database of milling force model,including the corresponding workpiece materials,working condition,cutting tools(geometric figures and coatings),and other parameters,should be established.(4)The effect of chatter on the prediction accuracy of milling force cannot be ignored in thin-walled workpiece milling.(5)The cutting force of aviation aluminum alloy milling under the condition of minimum quantity lubrication(mql)and nanofluid mql should be predicted.
基金supported by the National Special Funding Project for Water Pollution Control and Management of China(No.2009ZX07419-001,2008ZX07421-004)the Chinese Academy of Sciences Major Projects of Knowledge Innovation Program(No.kzcx-yw-06-02)the Special Co-construction Project of Beijing Municipal Commission of Education
文摘The method for detecting N-nitrosodimethylamine （NDMA） in drinking water using ultra performance liquid chromatography （UPLC） coupled with tandem mass spectrometry （MS/MS） was improved by optimizing the clean-up procedure to remove the matrix interference in pretreatment process, and was then applied to a survey of NDMA in both raw and finished water samples from five water treatment plants in South China. The NDMA concentrations ranged from 4.7 to 15.1 ng/L in raw water samples, and from 4.68 to 46.9 ng/L in finished water. The NDMA concentration in raw water was found to be related with nitrite concentration, and during the treatment, the NDMA concentration increased following ozonation but decreased after subsequent activated carbon treatment.
基金Supported by National Key Research and Development Program of China,No.2018YFC1313900 and No.2018YFC1313901The Higher School High-end Talent Team Construction of Liaoning Province,No.[2014]187.
文摘BACKGROUND Type 2 diabetes mellitus(T2DM)is significantly increasing worldwide,and the incidence of its complications is also on the rise.One of the main complications of T2DM is diabetic kidney disease(DKD).The glomerular filtration rate(GFR)and urinary albumin creatinine ratio(UACR)increase in the early stage.As the disease progresses,UACR continue to rise and GFR begins to decline until endstage renal disease appears.At the same time,DKD will also increase the incidence and mortality of cardiovascular and cerebrovascular diseases.At present,the pathogenesis of DKD is not very clear.Therefore,exploration of the pathogenesis of DKD to find a treatment approach,so as to delay the development of DKD,is essential to improve the prognosis of DKD.AIM To detect the expression of tenascin-C(TNC)in the serum of T2DM patients,observe the content of TNC in the glomerulus of DKD rats,and detect the expression of TNC on inflammatory and fibrotic factors in rat mesangial cells(RMCs)cultured under high glucose condition,in order to explore the specific molecular mechanism of TNC in DKD and bring a new direction for the treatment of DKD.METHODS The expression level of TNC in the serum of diabetic patients was detected by enzyme-linked immunosorbent assay(ELISA),the protein expression level of TNC in the glomerular area of DKD rats was detected by immunohistochemistry,and the expression level of TNC in the rat serum was detected by ELISA.Rat glomerular mesangial cells were cultured.Following high glucose stimulation,the expression levels of related proteins and mRNA were detected by Western blot and polymerase chain reaction,respectively.RESULTS ELISA results revealed an increase in the serum TNC level in patients with T2DM.Increasing UACR and hypertension significantly increased the expression of TNC(P<0.05).TNC expression was positively correlated with glycosylated haemoglobin(HbA1c)level,body mass index,systolic blood pressure,and UACR(P<0.05).Immunohistochemical staining showed that TNC expression in the glomeruli of rats with streptozotocin-induced diabetes was significantly increased compared with normal controls(P<0.05).Compared with normal rats,serum level of TNC in diabetic rats was significantly increased(P<0.05),which was positively correlated with urea nitrogen and urinary creatinine(P<0.05).The levels of TNC,Toll-like receptor-4(TLR4),phosphorylated nuclear factor-κB p65 protein(Ser536)(p-NF-κB p65),and miR-155-5p were increased in RMCs treated with high glucose(P<0.05).The level of TNC protein peaked 24 h after high glucose stimulation(P<0.05).After TNC knockdown,the levels of TLR4,p-NF-κB p65,miR-155-5p,connective tissue growth factor(CTGF),and fibronectin(FN)were decreased,revealing that TNC regulated miR-155-5p expression through the TLR4/NF-κB p65 pathway,thereby regulating inflammation(NF-κB p65)and fibrosis(CTGF and FN)in individuals with DKD.In addition,metformin treatment may relive the processes of inflammation and fibrosis in individuals with DKD by reducing the levels of the TNC,p-NF-κB p65,CTGF,and FN proteins.CONCLUSION TNC can promote the occurrence and development of DKD.Interfering with the TNC/TLR4/NF-κB p65/miR-155-5p pathway may become a new target for DKD treatment.
基金supported by the Projects of The National Key Research and Development Program of China(grant number 2016YFD0501204)Sichuan provincial project on S&T application and demonstration(grant number2016CC0070)the project on commercialization of research findings under funding of government of Sichuan province(grant number16ZHSF0385).
文摘Background:This study aimed to investigate the effects of oral administration of Enterococcus faecium NCIMB10415(E.faecium)on intestinal development,immunological parameters and gut microbiota of neonatal piglets challenged with enterotoxigenic Escherichia coli K88(ETEC).A total of 961-day-old sow-reared piglets were randomly assigned to 2 groups,with 48 piglets in each group.The piglets were from 16 litters(6 piglets each litter),and 3 piglets each litter were allocated to the E.faecium-supplemented(PRO)group,while the other 3 piglets were allocated to the control(CON)group.After colostrum intake,piglets in the PRO group were orally administrated with 3×10~9 CFU E.faecium per day for a period of one week.On day 8,one piglet per litter from each group was challenged(CON+ETEC,PRO+ETEC)or not(CON-ETEC,PRO-ETEC)with ETEC in a 2×2 factorial arrangement of treatments.On day 10(2 days after challenge),blood and tissue samples were obtained from piglets.Results:Before ETEC challenge,there were no significant differences for the average daily gain(ADG)and fecal score between the two groups of piglets.After ETEC challenge,the challenged piglets had greater fecal score compared to the non-challenged piglets,whereas E.faecium administration was able to decrease the fecal score.Piglets challenged with ETEC had shorter villous height,deeper crypt depth,and reduced number of goblet cells in the jejunum and decreased m RNA abundance of claudin-1 in the ileum,whereas increased the percentage of lymphocytes,concentrations of IL-1βin the plasma and TNF-αin the ileal mucosa,as well as increased the m RNA abundances of innate immunity-related genes in the ileum tissue.These deleterious effects caused by ETEC were partly alleviated by feeding E.faecium.In addition,piglets in PRO-ETEC group had decreased the percentage of CD8^+T cells of the peripheral blood when compared to those in CON-ETEC group.Moreover,E.faecium administration increased Verrucomicrobia at phylum level and decreased Bilophila at genus level.Conclusions:These results suggest that oral administration of E.faecium alleviated the intestinal injury and diarrhea severity of neonatal piglets challenged by ETEC,partly through improving the intestinal microbiota and immune response.This offers a potential strategy of dietary intervention against intestinal impairment by ETEC in neonatal piglets.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.51975305,51905289,52105457 and 52105264)National key Research and Development plan(2020YFB2010500)+2 种基金Key projects of Shandong Natural Science Foundation of China(Grant Nos.ZR2020KE027,ZR2020ME158 and ZR2021QE116)Major Science and technology innovation engineering projects of Shandong Province(Grant No.2019JZZY020111)Source Innovation Project of Qingdao West Coast New Area(Grant Nos.2020-97 and 2020-98).
文摘Metal cutting fluids(MCFs)under flood conditions do not meet the urgent needs of reducing carbon emission.Biolubricant-based minimum quantity lubrication(MQL)is an effective alternative to flood lubrication.However,pneumatic atomization MQL has poor atomization properties,which is detrimental to occupational health.Therefore,electrostatic atomization MQL requires preliminary exploratory studies.However,systematic reviews are lacking in terms of capturing the current research status and development direction of this technology.This study aims to provide a comprehensive review and critical assessment of the existing understanding of electrostatic atomization MQL.This research can be used by scientists to gain insights into the action mechanism,theoretical basis,machining performance,and development direction of this technology.First,the critical equipment,eco-friendly atomization media(biolubricants),and empowering mechanisms of electrostatic atomization MQL are presented.Second,the advanced lubrication and heat transfer mechanisms of biolubricants are revealed by quantitatively comparing MQL with MCF-based wet machining.Third,the distinctive wetting and infiltration mechanisms of electrostatic atomization MQL,combined with its unique empowering mechanism and atomization method,are compared with those of pneumatic atomization MQL.Previous experiments have shown that electrostatic atomization MQL can reduce tool wear by 42.4%in metal cutting and improve the machined surface Ra by 47%compared with pneumatic atomization MQL.Finally,future development directions,including the improvement of the coordination parameters and equipment integration aspects,are proposed.
文摘Minimum quantity Lubrication(MQL)is a sustainable lubrication system that is famous in many machining systems.It involve the spray of an infinitesimal amount of mist-like lubricants during machining processes.The MQL system is affirmed to exhibit an excellent machining performance,and it is highly economical.The nanofluids are understood to exhibit excellent lubricity and heat evacuation capability,compared to pure oil-based MQL system.Studies have shown that the surface quality and amount of energy expended in the grinding operations can be reduced considerably due to the positive effect of these nanofluids.This work presents an experimental study on the tribological performance of SiO_(2)nanofluid during grinding of Si_(3)N_(4)ceramic.The effect different grinding modes and lubrication systems during the grinding operation was also analyzed.Different concentrations of the SiO_(2)nanofluid was manufactured using canola,corn and sunflower oils.The quantitative evaluation of the grinding process was done based on the amount of grinding forces,specific grinding energy,frictional coefficient,and surface integrity.It was found that the canola oil exhibits optimal lubrication performance compared to corn oil,sunflower oil,and traditional lubrication systems.Additionally,the introduction of ultrasonic vibrations with the SiO_(2)nanofluid in MQL system was found to reduce the specific grinding energy,normal grinding forces,tangential grinding forces,and surface roughness by 65%,57%,65%,and 18%respectively.Finally,regression analysis was used to obtain an optimum parameter combinations.The observations from this work will aid the smooth transition towards ecofriendly and sustainable machining of engineering ceramics.
基金supported by the National Natural Scientific Foundation of China (No.21437005)
文摘Recently, the rarely reported tet(31) tetracycline resistance determinant was commonly found in Aeromonas salmonicida, Gallibacterium anatis, and Oblitimonas alkaliphila isolated from farming animals and related environment. However, its distribution in other bacteria and potential molecular dissemination mechanism in environment are still unknown. The purpose of this study was to investigate the potential mechanism underlying dissemination of tet(31) by analysing the tet(31)-carrying fragments in A. caviae strains isolated from an aerobic biofilm reactor treating oxytetracycline bearing wastewater. Twenty-three A. caviae strains were screened for the tet(31) gene by polymerase chain reaction(PCR). Three strains(two harbouring tet(31), one not) were subjected to whole genome sequencing using the PacBio RSII platform. Seventeen A. caviae strains carried the tet(31) gene and exhibited high resistance levels to oxytetracycline with minimum inhibitory concentrations(MICs)ranging from 256 to 512 mg/L. tet(31) was comprised of the transposon Tn6432 on the chromosome of A. caviae, and Tn6432 was also found in 15 additional tet(31)-positive A. caviae isolates by PCR. More important, Tn6432 was located on an integrative conjugative element(ICE)-like element, which could mediate the dissemination of the tet(31)-carrying transposon Tn6432 between bacteria. Comparative analysis demonstrated that Tn6432 homologs with the structure ISCR2-ΔphzF-tetR(31)-tet(31)-ΔglmM-sul2 were also carried by A. salmonicida, G. anatis, and O. alkaliphila, suggesting that this transposon can be transferred between species and even genera. This work provides the first report on the identification of the tet(31) gene in A. caviae, and will be helpful in exploring the dissemination mechanisms of tet(31) in water environment.
基金supported by the National Natural Science Foundation of China (No.21077118)the National Special Funding Project for Water Pollution Control and Management of China (No.2009ZX07419-001)
文摘The formation of toxic nitrogenous disinfection byproducts （N-DBPs）, such as nitrosamines, halonitromethanes and haloacetonitriles, from reactions between chlorine/chloramine and dissolved organic nitrogen in drinking water has caused great concern with regarding public health. This study revealed the occurrence of 17 aliphatic amines, some of which have been confirmed to be the precursors of N-DBPs, in source water across China. A sensitive method based on benzenesulfonyl chloride derivatization and liquid-liquid extraction followed by GC-MS analysis was established for the simultaneous analysis of the selected amines in aqueous samples. In total, 37 source water samples from the capital cities of 20 provinces were collected for the survey. Among the 17 amines, 14 were detected with an average frequency of detection of 36%. The most relevant amines in terms of frequency and maximum concentrations detected were dimethylamine （100%, 24.82 μg/L）, methylamine （78%, 0.92 μg/L）, N-methylethylamine （70%, 8.84 μg/L）, propylamine （59%, 10.69 μg/L）, diethylamine （54%, 3.76μg/L）, N-methylbutylamine （35%, 3.07 μg/L）, N-ethylpropylamine （35%, 0.52μg/L）, and piperidine （32%, 2.35 μg/L）. This is the first large scale survey of the aliphatic amines occurrence in source water in the world. The wide presence of nitrosamine precursors like dimethylamine, N-methylethylamine and diethylamine, and the precursors of haloacetonitriles and halonitromethanes like methylamine and propylamine suggests that better source water management is required to ensure the safety of drinking water.
基金the supports provided by the National Key Research and Development Program of China(Nos.2017YFB0702902 and 2016YFB0701405)the National Science and Technology Major Project(Nos.2017-VI-0001-0070 and 2017-Ⅵ-0002-0072)+1 种基金the National Natural Science Foundation of China(Nos.51971174 and 51771148)the Natural Science Basic Research Plan in Shaanxi Province of China(No.2020JM-121)。
文摘The double minimum creep,characterized by two creep rate minima,in Co-based superalloy is investigated using a phase-field model coupled with a crystal plasticity model.The constitutive modeling,based on the dislocation slip theory considering dislocation interaction,is applied to simulate microstructural evolution and deformation behavior.Rafting process commences at the beginning of creep until the global minimum of creep rate is reached,demonstrating a strengthening effect from N-type rafts under compressive creep.The high shear strain rate of(111)[011]slip system in the intersections of horizontal and verticalγchannels leads to a slight increase of creep rate after the first local minimum.The evolution of stress field shows that the softening effect is the combined effect of the increase of resolved shear stress and the decrease of hardening stress in the intersections.Further,these changes in stress are primarily caused by the dislocation annihilation and the inhomogeneous plastic deformation.This study indicates that the intermediate local softening stage during creep may be eliminated if the initial inter-distance betweenγ’precipitates is decreased.
基金the National Natural Science Foundation of China(Nos.21004017 and 21004043)the Natural Science Foundation of Hebei Provinee(No.B2015202049).
文摘In order to promote the thermostability of a-diimine nickel complex by ligand backbone structure,a series of α-diimine nickel complexes with substituents on acenaphthequinone backbone were synthesized and used as catalysts for ethylene polymerization.When the hydroxyethyl phenoxyl group was introduced to the acenaphthequinone-backbone,the thermal stability and activity of the catalyst could be significantly improved.The catalytic activity of complex C2[5-(4-(2-hydroxyethyl)phenoxyl)-N,N-bis(2,6-diisopropyl)acenaphthylene-1,2-diimine]nickel(Ⅱ)dibromide with isopropyl substituents on N-aryl reached 8.2×10^6g/(molNi·h)at 70℃and 2 MPa.The activity of[5-(4-(2-hydroxyethyl)phenoxyl)-N,N-bis(2,6-dibenzhydryl-4-menthylphenyl)acenaphthylene-1,2-diimine]nickel(Ⅱ)dibromide(C3)still maintained at 6.7×10^5 g/(molNi·h)at 120℃.Compared with C3 containing bulky dibenzhydryl substituents,the activity of C2 was sensitive to the change of the polymerization pressure.However,the polyethylenes obtained from complex C3 had lower branching density.Meanwhile,the molecular weight could reach 971 kg/mol,which is almost 5 times as much as that of the polyethylene obtained from complex C2.
基金financial support from the Independent Innovation Plan of Colleges and Universities in Ji’nanthe Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry
文摘The influence of the tool profiles on the thermo-mechanical interaction between AA6061-T6 workpiece and tool during friction stir welding was investigated. A customized experimental setup was employed to measure the feature points temperature and tool spindle torque in the process of FSW. Microstructure and tensile properties of stir zone (SZ) were characterized. Results indicate that the shoulder and pin geometries were responsible for the heat generation, tool torque variation at the plunging stage as well as the cross section contour of SZ, respectively. Finer grains in SZ resulted from flutes on shoulder and grooves on pin. Flat faces on the pin resulted in inhomogeneous grain size. Weld with higher 0.2% yield strength of 173 MPa was obtained by using the cylindrical pin tool while higher elongation weld of 32.0% was produced with triflat threaded pin tool.
基金supported by the National Natural Science Foundation of China (No. 21377144, 50938007,)the Funds for Major Science and Technology Program for Water Pollution Control and Treatment (No. 2012ZX07403-002-02)the Key Scientific and Technological Projects of Science and Technology Commission of Shanghai Municipality (No. 12231201600)
文摘Taste and odor （T/O） in drinking water often cause consumer complaints and are thus regulated in many countries. However, people in different regions may exhibit different sensitivities toward WO. This study proposed a method to determine the regional drinking water odorant regulation goals （ORGs） based on the odor sensitivity distribution of the local population. The distribution of odor sensitivity to 2-methylisobomeol （2-MIB） by the local population in Beijing, China was revealed by using a normal distribution function/model to describe the odor complaint response to a 2-MIB episode in 2005, and a 2-MIB concentration of 12.9 ng/L and FPA （flavor profile analysis） intensity of 2.5 was found to be the critical point to cause odor complaints. Thus the Beijing ORG for 2-MIB was determined to be 12.9 ng/L. Based on the assumption that the local FPA panel can represent the local population in terms of sensitivity to odor, and that the critical FPA intensity causing odor complaints was 2.5, this study tried to determine the ORGs for seven other cities of China by performing FPA tests using an FPA panel from the corresponding city. ORG values between 12.9 and 31.6 ng/L were determined, showing that a unified ORG may not be suitable for drinking water odor regulations. This study presents a novel approach for setting drinking water odor regulations.
基金supported by the Project of International Cooperation and Exchanges NSFC(No.31861143049)the National Natural Scientific Foundation of China(Nos.51978645,21437005)the China Postdoctoral Science Foundation(No.2019M661756).
文摘The tet C gene has been found to be one of the most widely distributed tetracycline resistance( tet) genes in various environmental niches, but the detailed dissemination mechanisms are still largely unknown. In the present study, 11 tet C-containing Aeromonas media strains were isolated from an aerobic biofilm reactor under oxytetracycline stresses, and the genome of one strain was sequenced using the Pac Bio RSII sequencing approach to reveal the genetic environment of tet C. The tet C gene was carried by an IS 26 composite transposon, named Tn 6434. The tet C-carrying Tn 6434 structure was detected in all of the A. media strains either in a novel plasmid p Aeme2( n = 9) or other DNA molecules( n = 2) by PCR screening. The NCBI database searching result shows that this structure was also present in the plasmids or chromosomes of other 13 genera, indicating the transferability of Tn 6434. Inverse PCR and sequencing confirmed that Tn 6434 can form a circular intermediate and is able to incorporate into a preexisting IS 26 element, suggesting that Tn 6434 might be responsible for the dissemination of tet C between different DNA molecules. This study will be helpful in uncovering the spread mechanism of tet genes in water environments.
基金financial supports from National Natural Science Foundation of China(No.22204169)Gansu Natural Science Foundation(Nos.23JRRA619,21JR7RA076)Scientific and Technological Program of Chengguan District,Lanzhou(No.2023JSCX0037)。
文摘A novel amine-modified pillar[5]arene bonded porous silica adsorbent(DETA-P5S)was designed to be applied to dynamic CO_(2)adsorption and selective separation of CO_(2)over N_(2)and CH_(4)gases mixture.The results demonstrated that reasonable introduction of DETA into the BE-P5 bonded silica support has sig nificantly increased the adsorption capacity of CO_(2).The DETA-P5S has the optimal adsorption capacity of 9.1 mmol/g with 5 vol%CO_(2)at 40℃.The main reason of this increased capacity could be attributed to the enhanced CO_(2)diffusion into porous adsorbent for its better dispersion in the pores of amine pillar[5]arene cavity and active site of DETA.Furthermore,the dynamic saturation adsorption capacitie of DETA-P5S were 7.11(0.37)and 6.18(0.44)mmol/g for CO_(2)/N_(2)and CO_(2)/CH_(4),respectively,both the ga mixtures showed high separation selectivity.Simultaneously,the DETA-P5S can maintain outstanding CO_(2)adsorption capacity after fifteen regeneration cycles.Consequently,the designed DETA-P5S could serve a a promising adsorbent for CO_(2)capture and storage.
