Background:Excessive use of inorganic trace minerals(ITMs)in swine production leads to high fecal mineral excretion and environmental risks,while most studies on organic trace minerals(OTMs)focus on single elements,wi...Background:Excessive use of inorganic trace minerals(ITMs)in swine production leads to high fecal mineral excretion and environmental risks,while most studies on organic trace minerals(OTMs)focus on single elements,with limited data on the synergistic effects and molecular mechanisms of combined OTMs(Fe,Cu,Mn,Zn)in growing-finishing pigs.Methods:This study aimed to investigate the effects of graded levels of micromineral proteinates(combined OTMs)on growth performance,mineral metabolism,and mRNA expression of mineral regulatory proteins.A total of 360 crossbred Duroc×Landrace×Large White pigs(initial body weight 47.1±4.8 kg)were randomly assigned to 6 dietary treatments:basal diet without microminerals(CON),basal diet with ITMs at commercially recommended levels(IT),and basal diets with 15%(OT 15%),25%(OT 25%),35%(OT 35%)commercially recommended levels(CRL)of combined micromineral proteinates.After a 70-day feeding trial,samples were analyzed using ICP-OES,ELISA,and RT-qPCR.Results:Results showed that reduced levels(15-35%CRL)of micromineral proteinates did not significantly affect average daily gain,average daily feed intake,or feed conversion ratio(gain-to-feed ratio)compared to IT(P>0.05),but significantly increased plasma Cu(1.73-1.83μg/mL)and Zn(1.72-1.97μg/mL)concentrations(P<0.05)and elevated activities of Cu/Zn-superoxide dismutase(32.9-35.9 U/L)and manganese superoxide dismutase(20.5-24.1 U/L)compared to CON(P<0.05),with no significant differences from IT(P>0.05).Fecal excretion of Fe,Cu,Mn,and Zn was significantly reduced by 35-50%in OT 15%-OT 35%groups compared to IT(P<0.05).OT 25%group exhibited the highest apparent absorptivity of Fe(38.5%),Cu(27.8%),and Zn(42.4%)(P<0.05),which was associated with significantly regulated mRNA expression of mineral regulatory proteins:upregulated DMT1,FPN1,ZIP4,and MT1A in the duodenum,and modulated HAMP,ATP7B,ZIP14,and ZnT1 in the liver(P<0.05).Conclusion:In conclusion,dietary supplementation with 25%CRL or less of combined micromineral proteinates can fully meet the nutritional needs of growing-finishing pigs,improve mineral absorptivity,and reduce fecal mineral excretion by regulating intestinal and hepatic mineral transport and homeostatic proteins,providing a sustainable alternative to high-dose ITMs.展开更多
Background: The objective of this study was to determine the effects of supplementing Cu on growth performance, Cu metabolism and Cu-related enzyme activities of weanling pigs fed diets with two different Cu sources, ...Background: The objective of this study was to determine the effects of supplementing Cu on growth performance, Cu metabolism and Cu-related enzyme activities of weanling pigs fed diets with two different Cu sources, and to estimate optimal Cu requirements and relative bioavailability from these two sources for pigs.Methods: Weanling pigs were allocated to 14 treatments arranged factorially, including 6 added Cu levels(5, 10,20, 40, 80, 160 mg/kg), and 2 mineral sources(tribasic Cu chloride, TBCC and copper proteinate, Cu Pro), as well as one negative control(0 mg/kg added Cu level) and one maximum allowed level treatment(200 mg/kg TBCC) for the entire 38-d experiment. Growth performance, mineral status and enzyme activities were measured at the end of this study.Results: Increasing levels of Cu showed linear and quadratic responses(P < 0.01) for final BW, ADG and FCR regardless of the sources. Supplementation with TBCC(> 80 mg/kg) and Cu Pro(> 20 mg/kg) significantly decreased(P < 0.05) diarrhea incidence of weanling pigs. There were linear and quadratic increases(P < 0.01) in bile, hepatic,and intestinal Cu concentrations, fecal Cu contents, and plasma enzyme activities(alkaline phosphatase,ceruloplasmin, Cu, Zn-Superoxide dismutase(Cu/Zn SOD), and glutathione peroxidase), whereas plasma malondialdehyde decreased(P < 0.01) linearly and quadratically as dietary Cu level increased. Similarly, pigs fed Cu Pro absorbed and retained more Cu and excreted less Cu than those fed TBCC when supplemented 80 mg/kg and above. Optimal dietary Cu requirements for pigs from 28 to 66 d of age estimated based on fitted broken-line models(P < 0.05) of bile Cu, plasma Cu/Zn SOD and growth performance were 93–140 mg/kg from TBCC, and 63–98 mg/kg from Cu Pro accordingly. According to slope ratios from multiple linear regression, the bioavailability value of Cu Pro relative to TBCC(100%) was 156–263%(P < 0.01).Conclusion: The findings indicated that Cu recommendation from current NRC(5–6 mg/kg) was not sufficient to meet the high requirement of weanling pigs. Cu from Cu Pro was significantly more bioavailable to weanling pigs than TBCC in stimulating growth and enzyme activities, decreasing diarrhea frequency and fecal Cu contents to the environment.展开更多
Eight of new 5-oxo-[1]benzopyrano[2,3-b]pyridines as the analogues of tetracycline, were designed and synthesized, and their affinity to the hydroxyapatite the inorganic composition of bone were tested.
Abstract: A concise route to a trachylobagibberellin analogue-dimethyl ester of 3-hydroxy-△1，10－12,16cyclogibberellin 12 was reported in this paper. starting from GA3 in eight steps.
Investigation of unloading rock failure under differentσ_(2)facilitates the control mechanism of excavation surrounding rock.This study focused on single-sided unloading tests of granite specimens under true triaxial...Investigation of unloading rock failure under differentσ_(2)facilitates the control mechanism of excavation surrounding rock.This study focused on single-sided unloading tests of granite specimens under true triaxial conditions.The strength and failure characteristics were studied with micro-camera and acoustic emission(AE)monitoring.Furthermore,the choice of test path and the effect ofσ_(2)on fracture of unloading rock were discussed.Results show that the increasedσ_(2)can strengthen the stability of single-sided unloading rock.After unloading,the rock’s free surface underwent five phases,namely,inoculation,particle ejection,buckling rupture,stable failure,and unstable rockburst phases.Moreover,atσ_(2)≤30 MPa,the b value shows the following variation tendency:rising,dropping,significant fluctuation,and dropping,with dispersed damages signal.Atσ_(2)≥40 MPa,the tendency shows:a rise,a decrease,a slight fluctuation,and final drop,with concentrated damages signal.After unloading,AE energy is mainly concentrated in the micro-energy range.With the increasedσ_(2),the micro-energy ratio rises.In contrast,low,medium and large energy ratios drop gradually.The increased tensile fractures and decreased shear fractures indicate that the failure mode of the unloading rock gradually changes from tensile-shear mode to tensile-split one.The fractional dimension of the rock fragments first increases and then decreases with an inflection point at 20 MPa.The distribution of SIF on the planes changes asσ_(2)increases,resulting in strengthening and then weakening of the rock bearing capacity.展开更多
Austenite antibacterial stainless steels have been found to have wide applications in hospitals and food industries. In recent years epsilon copper precipitation in antibacterial stainless steels has obtained much res...Austenite antibacterial stainless steels have been found to have wide applications in hospitals and food industries. In recent years epsilon copper precipitation in antibacterial stainless steels has obtained much research interest due to its antibacterial action. The objective of this study was to determine the effects of nitrogen concentration on the precipitation of epsilon copper and antibacterial property. Two kinds of austenite antibacterial stainless steels containing copper and different nitrogen concentration （0.02 and 0.08 wt pct, respectively） were prepared and the microstructures were characterized by a combination of electron microscopy and thermodynamic analysis. A mathematical expression was deduced to predict the effect of nitrogen concentration on the activity coefficient of copper, In（fCu/f^0cu）=0.53524＋4.11xN-0.48x^2N. Higher nitrogen was found to increase the free energy difference of copper concentration distribution between precipitation phase and austenite matrix, stimulate the aggregation of copper atoms from austenite, increase the precipitation amount and consequently enhance the antibacterial property of steel.展开更多
Background:Intrauterine growth restriction(IUGR)has negative impacts on the postnatal survival,growth and development of humans and animals,with not only on newborns but also adulthood.However,the characteristics for ...Background:Intrauterine growth restriction(IUGR)has negative impacts on the postnatal survival,growth and development of humans and animals,with not only on newborns but also adulthood.However,the characteristics for nutrient digestion and absorption in IUGR offspring are still largely unknown.Therefore,the normal birth weight(NBW)and IUGR growing pigs were used in this study to investigate their differences in nutrient utilization,with an expectition for further nutritional optimization of the IUGR offspring during their later life.Methods:Twelve IUGR and 12 NBW growing pigs were fitted with catheters in their portal vein to measure blood flow rate as well as nutrients and metabolites in plasma.The digestibilities of nutrients in different intestinal segments,and bacterial fermentation in the large intestine were examined to reveal the characteristics of nutrients utilization in IUGR versus NBW pigs.Results:The rate of portal venous blood flow did not differ beween IUGR and NBW pigs.Plasma concentrations of total cholesterol,triglycerides and glucose were much lower but those of urea were higher in the portal vein of IUGR pigs,compared with the NBW pigs.The ileal digestibility of dry matter,gross energy and starch were lower in IUGR pigs than in NBW pigs.IUGR increased hindgut microbial diversity and bacterial fermentation activity in the caecum.In vitro cross-fermentation of ileal digesta by caecal microbes of NBW and IUGR pigs showed that gas production was much higher for IUGR ileal digesta regardless of the source of caecal inocula.Conclusion:IUGR impairs the nutrient digestion and absorption in small intestine,reduces caecal microbial diversity and promotes bacterial fermentation in the large intestine during the growing phase.These findings aid in our understanding of nutrient metabolism in IUGR pigs and provide the basis for future nutritional interventions.展开更多
Solder paste quality can be improved from microstructure and surface status of the solder powder.In this work,the micro-morphology of solder paste was observed and the particle surface condition was analyzed.Also,the ...Solder paste quality can be improved from microstructure and surface status of the solder powder.In this work,the micro-morphology of solder paste was observed and the particle surface condition was analyzed.Also,the conditions of corrosion and the corrosion products in different organic acid groups(activators)were analyzed.The result shows that the SnO passive film on the solder powder surface reacts with the COO-in the active agent of the solder paste.This reaction led the passivation layer to be peeled off.It also caused the change in solder powders’physical and chemical properties and made the metal boundary to be cold-welded.This is the root cause of solder paste exsiccation and deterioration.The study on the details shows that to obtain high-quality solder paste,one of the key methods is using the solder powder with ideal passivation shell structure and defect-free surface.展开更多
The precipitation of epsilon copper at 1023 K ageing in ferrite antibacterial stainless steel was investigated by a combination of electron microscopy and micro-Vickers hardness measurement. The results show that epsi...The precipitation of epsilon copper at 1023 K ageing in ferrite antibacterial stainless steel was investigated by a combination of electron microscopy and micro-Vickers hardness measurement. The results show that epsilon copper precipitation occurs within 90 s, Complex multilayer structure confirmed as twins and stacking faults on {111}ε-Cu planes was observed in the precipitates. The precipitates grow by the lengthwise enlargement of a set of parallel layers, having [111]ε-Cu and [112]ε-Cu preferred growth orientations. The volume fraction of precipitates f formed within 120 min can be predicted by a modified Avrami equation （In1/1-f= kt ＋ b）. Simultaneously, substituent atom clusters with a size of 5-10 nm was found to occur in the solution and cause matrix strain. The precipitate morphology and distribution on the surface of ferrite antibacterial stainless steel are associated with surface crystallographic orientation of the matrix. The precipitates are predominantly located within the ferrite grains of 〈110〉 orientation. The precipitates located on {111}α-Fe surface planes have sphere or ellipse shape.展开更多
Health is maintained by a state of dynamic homeostasis in which nutrient intake and ex- penditure are of good balance. Therefore, it is important to know exactly the nutritional value of food sources, as well as the n...Health is maintained by a state of dynamic homeostasis in which nutrient intake and ex- penditure are of good balance. Therefore, it is important to know exactly the nutritional value of food sources, as well as the nutritional requirements of individuals, in order to achieve optimal nutrition. Considering the interaction between diet and individual back- ground, nutritional evaluation and recommendation has become a complicate issue needing further investigations. While traditional nutrition research has made significant progress in population nutrition, modern nutrition research is now becoming possible to focus on personalized nutrition in health promotion, disease prevention, performance improvement, and risk assessment of individual with the development of emerging omics technologies. This review tried to summarize the methods used in nutritional evaluation and recom- mendation as well as their applications. Though personal nutrition evaluation and recommendation are still not well-established, utilization of these advanced technologies may expand our knowledge in bioavailability and bioefficacy of diet ingredients, pathophysiological changes in response to dietary intervention, as well as nutrition-associated disease biomarkers discovery, and thus contributing to personalized nutrition.展开更多
By merging two standard swirl chambers,an alternative cooling configuration named double swirl chambers(DSC)has been developed.In the DSC cooling configuration,the main physical phenomena of the swirl flow in swirl ch...By merging two standard swirl chambers,an alternative cooling configuration named double swirl chambers(DSC)has been developed.In the DSC cooling configuration,the main physical phenomena of the swirl flow in swirl chamber and the advantages of swirl flow in heat transfer augmentation are maintained.Additionally,three new physical phenomena can be found in DSC cooling configuration,which result in a further improvement of the heat transfer:(1)impingement effect has been observed,(2)internal heat exchange has been enhanced between fluids in two swirls,and(3)“∞”shape swirl has been generated because of cross effect between two chambers,which improves the mixing of the fluids.Because of all these improvements,the DSC cooling configuration leads to a higher globally-averaged thermal performance parameter(Nu/Nu_(∞)/(f/f0)^(1/3))than standard swirl chamber.In particular,at the inlet region,the augmentation of the heat transfer is nearly 7.5 times larger than the fully developed non-swirl turbulent flow and the circumferentially averaged Nusselt number coefficient is 41%larger than the standard swirl chamber.Within the present work,a further investigation on the DSC cooling configuration has been focused on the influence of geometry parameters e.g.merging ratio of chambers and aspect ratio of inlet duct on the cooling perfomance.The results show a very large influence of these geometry parameters in heat transfer enhancement and pressure drop ratio.Compared with the basic configuration of DSC cooling,the improved configuration with 20%to 23%merging ratio shows the highest globally-averaged themal performance parameter.With the same cross section area in tangential inlet ducts,the DSC cooling channel with larger aspect ratio shows larger heat transfer enhancement and at the same time reduced pressure drop ratio,which results in a better globally-averaged themal performance parameter.展开更多
Copper(Cu)is an essential trace element in the production of swine.This study was conducted to investigate the effect of 3 different sources of Cu on growth performance,Cu metabolism,and intestinal microorganisms of f...Copper(Cu)is an essential trace element in the production of swine.This study was conducted to investigate the effect of 3 different sources of Cu on growth performance,Cu metabolism,and intestinal microorganisms of finishing pigs,so as to estimate the bioavailability of the 3 sources for pigs.A total of 42 male finishing pigs(88.74±5.74 kg)were randomly allocated to 7 treatments.The factors were 3 sources(CuSO4,Cu-glycine,Cu-proteinate)and 2 levels(5 and 20 mg/kg)of Cu,plus one negative control treatment(0 mg/kg added Cu level)for the entire 28-d experiment.The average daily gain(ADG)and feed to gain ratio(F:G)both increased when Cu was added.The Cu level in liver,bile,kidney,serum,lung,urine and feces rose(P<0.001)with increasing dietary Cu level regardless of the source.Meanwhile,pigs receiving organic Cu(glycinate or proteinate)retained more Cu and excreted less Cu than those receiving inorganic Cu(CuSO4),which showed that organic forms were more bioavailable.At the transcriptional level,changes in the level and source of dietary Cu resulted in modulation of transporters.In the jejunal mucosa,import transporter high affinity copper uptake protein 1(CTR1)and export transporter ATPase copper transporting alpha(ATP7A)in supplemental Cu treatments were down-regulated compared to the control.Also,peptide transporter 1(PepT1)and lanine-serine-cysteine transporter,type-2(ASCT2)were significantly(P<0.01)up-regulated in 20 mg/kg Cu-proteinate and Cu-glycinate treatments,respectively.Microbial diversity was lowest in the 20 mg/kg CuSO4 treatment,and the ratio of Firmicutes to Bacteroidetes was higher in added Cu treatments,especially Cu-glycinate treatment.These results indicate that uptake of different Cu forms is facilitated by different transporters and transport mechanisms,and compared with inorganic Cu,organic Cu provides benefits to intestinal microflora and reduces Cu excretion.展开更多
To reduce greenhouse gas(GHG)emissions,biomass has been increasingly developed as a renewable and clean alternative to fossil fuels because of its carbon-neutral characteristics.China has been investigating the ration...To reduce greenhouse gas(GHG)emissions,biomass has been increasingly developed as a renewable and clean alternative to fossil fuels because of its carbon-neutral characteristics.China has been investigating the rational development and use of bioenergy for developing its clean energy and achieving carbon neutrality.Substituting fossil fuels with multi-source and multi-approach utilized bioenergy and corresponding carbon reduction in China remain largely unexplored.Here,a comprehensive bioenergy accounting model with a multi-dimensional analysis was developed by combining spatial,life cycle,and multi-path analyses.Accordingly,the bioenergy production potential and GHG emission reduction for each distinct type of biomass feedstock through different conversion pathways were estimated.The sum of all available organic waste(21.55 EJ yr^(-1))and energy plants on marginal land(11.77 EJ yr^(-1))in China produced 23.30 EJ of bioenergy and reduced 2,535.32 Mt CO_(2)-eq emissions,accounting for 19.48%and 25.61%of China’s total energy production and carbon emissions in 2020,respectively.When focusing on the carbon emission mitigation potential of substituting bioenergy for conventional counterparts,bioelectricity was the most effective,and its potential was 4.45 and 8.58 times higher than that of gaseous and liquid fuel alternatives,respectively.In this study,life cycle emission reductions were maximized by a mix of bioenergy end uses based on biomass properties,with an optimal 78.56%bioenergy allocation from biodiesel,densified solid biofuel,biohydrogen,and biochar.The main regional bioenergy GHG mitigation focused on the Jiangsu,Sichuan,Guangxi,Henan,and Guangdong provinces,contributing to 31.32%of the total GHG mitigation potential.This study provides valuable guidance on exploiting untapped biomass resources in China to secure carbon neutrality by 2060.展开更多
Isochrysis galbana is considered an ideal bait for functional foods and nutraceuticals of humans because of its high fucoxanthin(Fx)content.However,multi-omics analysis of the regulatory networks for Fx biosynthesis i...Isochrysis galbana is considered an ideal bait for functional foods and nutraceuticals of humans because of its high fucoxanthin(Fx)content.However,multi-omics analysis of the regulatory networks for Fx biosynthesis in I.galbana has not been reported.In this study,we report a high-quality genome assembly of I.galbana LG007,which has a genome size of 92.73 Mb,with a contig N50 of 6.99 Mb and 14,900 protein-coding genes.Phylogenetic analysis confirmed the monophyly of Haptophyta,with I.galbana sister to Emiliania huxleyi and Chrysochromulina tobinii.Evolutionary analysis revealed an estimated divergence time between I.galbana and E.huxleyi of~133 million years ago.Gene family analysis indicated that lipid metabolism-related genes exhibited significant expansion,including IgPLMT,IgOAR1,and IgDEGS1.Metabolome analysis showed that the content of carotenoids in I.galbana cultured under green light for 7 days was higher than that under white light,andβ-carotene was the main carotenoid,accounting for 79.09%of the total carotenoids.Comprehensive multi-omics analysis revealed that the content ofβ-carotene,antheraxanthin,zeaxanthin,and Fx was increased by green light induction,which was significantly correlated with the expression of IgMYB98,IgZDS,IgPDS,IgLHCX2,IgZEP,IgLCYb,and IgNSY.These findings contribute to the understanding of Fx biosynthesis and its regulation,providing a valuable reference for food and pharmaceutical applications.展开更多
To investigate the compression-shear behavior of a new circumferential joint based on the sleeve-straight bolt combination type connection of large-diameter shield tunnels,a series of full-scale joint experiments was ...To investigate the compression-shear behavior of a new circumferential joint based on the sleeve-straight bolt combination type connection of large-diameter shield tunnels,a series of full-scale joint experiments was carried out.In the process of the experiment,more attention was paid to the specimen displacement,bolt stress and joint damage mode.On the basis of these experiment phenomena,this study discussed the compression-shear bearing process of the new connector,analyzed the damage mode of the joint structure,and finally evaluated the performance of the new connector.It is found that the bearing process of the joint can be divided into four stages:the transitional stage for overcoming the friction of the concrete,the sleeve bearing stage for the sleeve bearing shear loads alone,the combined bearing stage for bearing shear loads by the connector system,and the structural damage stage for structural instability and damage.Generally speaking,affected by connector position and hand hole,the positive compression-shear stiffness of the joint is less than the negative compression-shear stiffness,and the positive shear strength of the joint is greater than the negative shear strength.The increase of longitudinal axial force will improve the compression-shear performance of the joint.The relationship between longitudinal axial force and joint stiffness is a logarithmic function.The use of new type of connector can effectively improve the compression-shear stiffness of joints under low shear loads,but the application of straight bolts will lose part of the strength performance.展开更多
Synthesis of ultrafine noble metal with sizes down to nanoscale and even atomic scale is of great significance for heterogeneous catalysis. However, the metal loading is usually kept below 2 wt% due to the aggregation...Synthesis of ultrafine noble metal with sizes down to nanoscale and even atomic scale is of great significance for heterogeneous catalysis. However, the metal loading is usually kept below 2 wt% due to the aggregation tendency at higher metal contents. Herein, by mimicking the multicentered metal sulfur cluster of metalloenzyme, a bioinspired synthesis of isolated noble metal atoms on the metal-organic sulfide(MOS) framework was reported. The sulfur-rich framework featuring [Mo_(3)S_(2)Br_(6)]^(2-) cluster as the building block and dithiol as the linking node was constructed via chemical bonding and employed to support atomic metal species. Remarkably, highly dispersed platinum atoms with a loading amount as high as 18.5 wt% on the underlying sulfurrich framework could be obtained after reduction. By increasing the number of benzene rings in the dithiol, the pore size and even the wettability of the MOS frameworks could be modulated. The general applicability of the synthesis could also be extended to the synthesis of atomic Pd. Furthermore,the Pt-loaded MOS could serve as the catalyst for selective hydrogenation of phenylacetylene to styrene in both organic solvent and pure water. Density function theory calculation demonstrated that the atomic Pt sites in the sulfur-rich coordination environment could activate H_(2) molecules and chemoselectively catalyze the semi-hydrogenation of phenylacetylene to styrene through moderately low energy barriers.The metalation of such a versatile MOS framework will shed light on the synthesis of bioinspired catalytic materials with well-defined structures for more diverse applications.展开更多
Voltage resonance and fluctuation deteriorate the stability of DC microgrids(DC-MGs)and restrict their popularization.Conventional droop control cannot suppress voltage fluctuation and damp oscillations.Therefore,new ...Voltage resonance and fluctuation deteriorate the stability of DC microgrids(DC-MGs)and restrict their popularization.Conventional droop control cannot suppress voltage fluctuation and damp oscillations.Therefore,new control methods,namely,droop+filter control and virtual inertia and damping control,are proposed.These methods differ owing to the addition of low pass filter(LPF)and virtual inertia loop.In this study,the stability of these control methods is investigated comprehensively to understand their differences arising from the use of LPF and inertia loop as well as the underlying dynamic stability mechanism.The leading causes of voltage instability in DC-MGs regulated by droop control are first presented.Subsequently,control methods for solving this issue are compared and their simplified small-signal models are constructed.Based on eigenvalue analysis,the DC-MG is equivalent to a third-order system.Different control effects can be acquired by changing the control parameters and the location of the eigenvalues;furthermore,they can be used to understand the dynamic stability.Eigenvalue analysis can provide parameter design guidelines.Finally,the simulation results verify the validity of the theoretical analysis.展开更多
基金financially supported by the Hainan Province Science and Technology Special Fund(Grant no:ZDYF2024XDNY187).
文摘Background:Excessive use of inorganic trace minerals(ITMs)in swine production leads to high fecal mineral excretion and environmental risks,while most studies on organic trace minerals(OTMs)focus on single elements,with limited data on the synergistic effects and molecular mechanisms of combined OTMs(Fe,Cu,Mn,Zn)in growing-finishing pigs.Methods:This study aimed to investigate the effects of graded levels of micromineral proteinates(combined OTMs)on growth performance,mineral metabolism,and mRNA expression of mineral regulatory proteins.A total of 360 crossbred Duroc×Landrace×Large White pigs(initial body weight 47.1±4.8 kg)were randomly assigned to 6 dietary treatments:basal diet without microminerals(CON),basal diet with ITMs at commercially recommended levels(IT),and basal diets with 15%(OT 15%),25%(OT 25%),35%(OT 35%)commercially recommended levels(CRL)of combined micromineral proteinates.After a 70-day feeding trial,samples were analyzed using ICP-OES,ELISA,and RT-qPCR.Results:Results showed that reduced levels(15-35%CRL)of micromineral proteinates did not significantly affect average daily gain,average daily feed intake,or feed conversion ratio(gain-to-feed ratio)compared to IT(P>0.05),but significantly increased plasma Cu(1.73-1.83μg/mL)and Zn(1.72-1.97μg/mL)concentrations(P<0.05)and elevated activities of Cu/Zn-superoxide dismutase(32.9-35.9 U/L)and manganese superoxide dismutase(20.5-24.1 U/L)compared to CON(P<0.05),with no significant differences from IT(P>0.05).Fecal excretion of Fe,Cu,Mn,and Zn was significantly reduced by 35-50%in OT 15%-OT 35%groups compared to IT(P<0.05).OT 25%group exhibited the highest apparent absorptivity of Fe(38.5%),Cu(27.8%),and Zn(42.4%)(P<0.05),which was associated with significantly regulated mRNA expression of mineral regulatory proteins:upregulated DMT1,FPN1,ZIP4,and MT1A in the duodenum,and modulated HAMP,ATP7B,ZIP14,and ZnT1 in the liver(P<0.05).Conclusion:In conclusion,dietary supplementation with 25%CRL or less of combined micromineral proteinates can fully meet the nutritional needs of growing-finishing pigs,improve mineral absorptivity,and reduce fecal mineral excretion by regulating intestinal and hepatic mineral transport and homeostatic proteins,providing a sustainable alternative to high-dose ITMs.
基金The financial support from the National Key Research and Development Program of China (2017YFC1600306) is gratefully acknowledged。
文摘Background: The objective of this study was to determine the effects of supplementing Cu on growth performance, Cu metabolism and Cu-related enzyme activities of weanling pigs fed diets with two different Cu sources, and to estimate optimal Cu requirements and relative bioavailability from these two sources for pigs.Methods: Weanling pigs were allocated to 14 treatments arranged factorially, including 6 added Cu levels(5, 10,20, 40, 80, 160 mg/kg), and 2 mineral sources(tribasic Cu chloride, TBCC and copper proteinate, Cu Pro), as well as one negative control(0 mg/kg added Cu level) and one maximum allowed level treatment(200 mg/kg TBCC) for the entire 38-d experiment. Growth performance, mineral status and enzyme activities were measured at the end of this study.Results: Increasing levels of Cu showed linear and quadratic responses(P < 0.01) for final BW, ADG and FCR regardless of the sources. Supplementation with TBCC(> 80 mg/kg) and Cu Pro(> 20 mg/kg) significantly decreased(P < 0.05) diarrhea incidence of weanling pigs. There were linear and quadratic increases(P < 0.01) in bile, hepatic,and intestinal Cu concentrations, fecal Cu contents, and plasma enzyme activities(alkaline phosphatase,ceruloplasmin, Cu, Zn-Superoxide dismutase(Cu/Zn SOD), and glutathione peroxidase), whereas plasma malondialdehyde decreased(P < 0.01) linearly and quadratically as dietary Cu level increased. Similarly, pigs fed Cu Pro absorbed and retained more Cu and excreted less Cu than those fed TBCC when supplemented 80 mg/kg and above. Optimal dietary Cu requirements for pigs from 28 to 66 d of age estimated based on fitted broken-line models(P < 0.05) of bile Cu, plasma Cu/Zn SOD and growth performance were 93–140 mg/kg from TBCC, and 63–98 mg/kg from Cu Pro accordingly. According to slope ratios from multiple linear regression, the bioavailability value of Cu Pro relative to TBCC(100%) was 156–263%(P < 0.01).Conclusion: The findings indicated that Cu recommendation from current NRC(5–6 mg/kg) was not sufficient to meet the high requirement of weanling pigs. Cu from Cu Pro was significantly more bioavailable to weanling pigs than TBCC in stimulating growth and enzyme activities, decreasing diarrhea frequency and fecal Cu contents to the environment.
文摘Eight of new 5-oxo-[1]benzopyrano[2,3-b]pyridines as the analogues of tetracycline, were designed and synthesized, and their affinity to the hydroxyapatite the inorganic composition of bone were tested.
文摘Abstract: A concise route to a trachylobagibberellin analogue-dimethyl ester of 3-hydroxy-△1，10－12,16cyclogibberellin 12 was reported in this paper. starting from GA3 in eight steps.
基金This work was supported by the Scientific Research Project of Anhui Province Universities,China(No.YJS20210388)the National Natural Science Foundation of China(Nos.51974009,52004006,and 52004005)+2 种基金the Major Science and Technology Special Project of Anhui Province,China(No.202203a07020011)the Collaborative Innovation Project of Anhui Province Universities,China(No.GXXT-2021-075)the Huaibei City Science and Technology Major Program(No.Z2020005).
文摘Investigation of unloading rock failure under differentσ_(2)facilitates the control mechanism of excavation surrounding rock.This study focused on single-sided unloading tests of granite specimens under true triaxial conditions.The strength and failure characteristics were studied with micro-camera and acoustic emission(AE)monitoring.Furthermore,the choice of test path and the effect ofσ_(2)on fracture of unloading rock were discussed.Results show that the increasedσ_(2)can strengthen the stability of single-sided unloading rock.After unloading,the rock’s free surface underwent five phases,namely,inoculation,particle ejection,buckling rupture,stable failure,and unstable rockburst phases.Moreover,atσ_(2)≤30 MPa,the b value shows the following variation tendency:rising,dropping,significant fluctuation,and dropping,with dispersed damages signal.Atσ_(2)≥40 MPa,the tendency shows:a rise,a decrease,a slight fluctuation,and final drop,with concentrated damages signal.After unloading,AE energy is mainly concentrated in the micro-energy range.With the increasedσ_(2),the micro-energy ratio rises.In contrast,low,medium and large energy ratios drop gradually.The increased tensile fractures and decreased shear fractures indicate that the failure mode of the unloading rock gradually changes from tensile-shear mode to tensile-split one.The fractional dimension of the rock fragments first increases and then decreases with an inflection point at 20 MPa.The distribution of SIF on the planes changes asσ_(2)increases,resulting in strengthening and then weakening of the rock bearing capacity.
文摘Austenite antibacterial stainless steels have been found to have wide applications in hospitals and food industries. In recent years epsilon copper precipitation in antibacterial stainless steels has obtained much research interest due to its antibacterial action. The objective of this study was to determine the effects of nitrogen concentration on the precipitation of epsilon copper and antibacterial property. Two kinds of austenite antibacterial stainless steels containing copper and different nitrogen concentration （0.02 and 0.08 wt pct, respectively） were prepared and the microstructures were characterized by a combination of electron microscopy and thermodynamic analysis. A mathematical expression was deduced to predict the effect of nitrogen concentration on the activity coefficient of copper, In（fCu/f^0cu）=0.53524＋4.11xN-0.48x^2N. Higher nitrogen was found to increase the free energy difference of copper concentration distribution between precipitation phase and austenite matrix, stimulate the aggregation of copper atoms from austenite, increase the precipitation amount and consequently enhance the antibacterial property of steel.
基金supported by the National Natural Science Foundation of China(31630074,31422052,31972596,31902189,31902170)the Beijing Municipal Natural Science Foundation(S170001)+2 种基金the China Agriculture Research System(CARS-35),the 111 Project(B16044)the Jinxinnong Animal Science Developmental Foundation,State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products(2018KLGM03)China Postdoctoral Science Foundation(2018 M630235)。
文摘Background:Intrauterine growth restriction(IUGR)has negative impacts on the postnatal survival,growth and development of humans and animals,with not only on newborns but also adulthood.However,the characteristics for nutrient digestion and absorption in IUGR offspring are still largely unknown.Therefore,the normal birth weight(NBW)and IUGR growing pigs were used in this study to investigate their differences in nutrient utilization,with an expectition for further nutritional optimization of the IUGR offspring during their later life.Methods:Twelve IUGR and 12 NBW growing pigs were fitted with catheters in their portal vein to measure blood flow rate as well as nutrients and metabolites in plasma.The digestibilities of nutrients in different intestinal segments,and bacterial fermentation in the large intestine were examined to reveal the characteristics of nutrients utilization in IUGR versus NBW pigs.Results:The rate of portal venous blood flow did not differ beween IUGR and NBW pigs.Plasma concentrations of total cholesterol,triglycerides and glucose were much lower but those of urea were higher in the portal vein of IUGR pigs,compared with the NBW pigs.The ileal digestibility of dry matter,gross energy and starch were lower in IUGR pigs than in NBW pigs.IUGR increased hindgut microbial diversity and bacterial fermentation activity in the caecum.In vitro cross-fermentation of ileal digesta by caecal microbes of NBW and IUGR pigs showed that gas production was much higher for IUGR ileal digesta regardless of the source of caecal inocula.Conclusion:IUGR impairs the nutrient digestion and absorption in small intestine,reduces caecal microbial diversity and promotes bacterial fermentation in the large intestine during the growing phase.These findings aid in our understanding of nutrient metabolism in IUGR pigs and provide the basis for future nutritional interventions.
基金financially supported by National Key R&D Program of China(No.2017YFB0305700)。
文摘Solder paste quality can be improved from microstructure and surface status of the solder powder.In this work,the micro-morphology of solder paste was observed and the particle surface condition was analyzed.Also,the conditions of corrosion and the corrosion products in different organic acid groups(activators)were analyzed.The result shows that the SnO passive film on the solder powder surface reacts with the COO-in the active agent of the solder paste.This reaction led the passivation layer to be peeled off.It also caused the change in solder powders’physical and chemical properties and made the metal boundary to be cold-welded.This is the root cause of solder paste exsiccation and deterioration.The study on the details shows that to obtain high-quality solder paste,one of the key methods is using the solder powder with ideal passivation shell structure and defect-free surface.
文摘The precipitation of epsilon copper at 1023 K ageing in ferrite antibacterial stainless steel was investigated by a combination of electron microscopy and micro-Vickers hardness measurement. The results show that epsilon copper precipitation occurs within 90 s, Complex multilayer structure confirmed as twins and stacking faults on {111}ε-Cu planes was observed in the precipitates. The precipitates grow by the lengthwise enlargement of a set of parallel layers, having [111]ε-Cu and [112]ε-Cu preferred growth orientations. The volume fraction of precipitates f formed within 120 min can be predicted by a modified Avrami equation （In1/1-f= kt ＋ b）. Simultaneously, substituent atom clusters with a size of 5-10 nm was found to occur in the solution and cause matrix strain. The precipitate morphology and distribution on the surface of ferrite antibacterial stainless steel are associated with surface crystallographic orientation of the matrix. The precipitates are predominantly located within the ferrite grains of 〈110〉 orientation. The precipitates located on {111}α-Fe surface planes have sphere or ellipse shape.
基金supported by the Beijing Excellent Talent Support Program(PYZZ090428001238)the National Natural Science Foundation of China(No.30828024,30972156)+1 种基金State Key Laboratory of Animal Nutrition(2004DA125184Team0815)SpecialPublic Sector Fund in Agriculture(200903006)
文摘Health is maintained by a state of dynamic homeostasis in which nutrient intake and ex- penditure are of good balance. Therefore, it is important to know exactly the nutritional value of food sources, as well as the nutritional requirements of individuals, in order to achieve optimal nutrition. Considering the interaction between diet and individual back- ground, nutritional evaluation and recommendation has become a complicate issue needing further investigations. While traditional nutrition research has made significant progress in population nutrition, modern nutrition research is now becoming possible to focus on personalized nutrition in health promotion, disease prevention, performance improvement, and risk assessment of individual with the development of emerging omics technologies. This review tried to summarize the methods used in nutritional evaluation and recom- mendation as well as their applications. Though personal nutrition evaluation and recommendation are still not well-established, utilization of these advanced technologies may expand our knowledge in bioavailability and bioefficacy of diet ingredients, pathophysiological changes in response to dietary intervention, as well as nutrition-associated disease biomarkers discovery, and thus contributing to personalized nutrition.
文摘By merging two standard swirl chambers,an alternative cooling configuration named double swirl chambers(DSC)has been developed.In the DSC cooling configuration,the main physical phenomena of the swirl flow in swirl chamber and the advantages of swirl flow in heat transfer augmentation are maintained.Additionally,three new physical phenomena can be found in DSC cooling configuration,which result in a further improvement of the heat transfer:(1)impingement effect has been observed,(2)internal heat exchange has been enhanced between fluids in two swirls,and(3)“∞”shape swirl has been generated because of cross effect between two chambers,which improves the mixing of the fluids.Because of all these improvements,the DSC cooling configuration leads to a higher globally-averaged thermal performance parameter(Nu/Nu_(∞)/(f/f0)^(1/3))than standard swirl chamber.In particular,at the inlet region,the augmentation of the heat transfer is nearly 7.5 times larger than the fully developed non-swirl turbulent flow and the circumferentially averaged Nusselt number coefficient is 41%larger than the standard swirl chamber.Within the present work,a further investigation on the DSC cooling configuration has been focused on the influence of geometry parameters e.g.merging ratio of chambers and aspect ratio of inlet duct on the cooling perfomance.The results show a very large influence of these geometry parameters in heat transfer enhancement and pressure drop ratio.Compared with the basic configuration of DSC cooling,the improved configuration with 20%to 23%merging ratio shows the highest globally-averaged themal performance parameter.With the same cross section area in tangential inlet ducts,the DSC cooling channel with larger aspect ratio shows larger heat transfer enhancement and at the same time reduced pressure drop ratio,which results in a better globally-averaged themal performance parameter.
基金The financial support from the National Key Research and Development Program of China(2017YFC1600306)is gratefully acknowledged.
文摘Copper(Cu)is an essential trace element in the production of swine.This study was conducted to investigate the effect of 3 different sources of Cu on growth performance,Cu metabolism,and intestinal microorganisms of finishing pigs,so as to estimate the bioavailability of the 3 sources for pigs.A total of 42 male finishing pigs(88.74±5.74 kg)were randomly allocated to 7 treatments.The factors were 3 sources(CuSO4,Cu-glycine,Cu-proteinate)and 2 levels(5 and 20 mg/kg)of Cu,plus one negative control treatment(0 mg/kg added Cu level)for the entire 28-d experiment.The average daily gain(ADG)and feed to gain ratio(F:G)both increased when Cu was added.The Cu level in liver,bile,kidney,serum,lung,urine and feces rose(P<0.001)with increasing dietary Cu level regardless of the source.Meanwhile,pigs receiving organic Cu(glycinate or proteinate)retained more Cu and excreted less Cu than those receiving inorganic Cu(CuSO4),which showed that organic forms were more bioavailable.At the transcriptional level,changes in the level and source of dietary Cu resulted in modulation of transporters.In the jejunal mucosa,import transporter high affinity copper uptake protein 1(CTR1)and export transporter ATPase copper transporting alpha(ATP7A)in supplemental Cu treatments were down-regulated compared to the control.Also,peptide transporter 1(PepT1)and lanine-serine-cysteine transporter,type-2(ASCT2)were significantly(P<0.01)up-regulated in 20 mg/kg Cu-proteinate and Cu-glycinate treatments,respectively.Microbial diversity was lowest in the 20 mg/kg CuSO4 treatment,and the ratio of Firmicutes to Bacteroidetes was higher in added Cu treatments,especially Cu-glycinate treatment.These results indicate that uptake of different Cu forms is facilitated by different transporters and transport mechanisms,and compared with inorganic Cu,organic Cu provides benefits to intestinal microflora and reduces Cu excretion.
基金supported by the Youth Innovation Promotion Association,Chinese Academy of Sciences(2020201,Y202050,2018068)by the National Natural Science Foundation of China(41977290,41971250)+2 种基金by the Liaoning Xingliao Talents Project(XLYC1907148)by the Provincial Natural Science Foundation of Liaoning(2022-MS-031)by the Major Program of Institute for Applied Ecology,Chinese Academy of Sciences(IAEMP202201).
文摘To reduce greenhouse gas(GHG)emissions,biomass has been increasingly developed as a renewable and clean alternative to fossil fuels because of its carbon-neutral characteristics.China has been investigating the rational development and use of bioenergy for developing its clean energy and achieving carbon neutrality.Substituting fossil fuels with multi-source and multi-approach utilized bioenergy and corresponding carbon reduction in China remain largely unexplored.Here,a comprehensive bioenergy accounting model with a multi-dimensional analysis was developed by combining spatial,life cycle,and multi-path analyses.Accordingly,the bioenergy production potential and GHG emission reduction for each distinct type of biomass feedstock through different conversion pathways were estimated.The sum of all available organic waste(21.55 EJ yr^(-1))and energy plants on marginal land(11.77 EJ yr^(-1))in China produced 23.30 EJ of bioenergy and reduced 2,535.32 Mt CO_(2)-eq emissions,accounting for 19.48%and 25.61%of China’s total energy production and carbon emissions in 2020,respectively.When focusing on the carbon emission mitigation potential of substituting bioenergy for conventional counterparts,bioelectricity was the most effective,and its potential was 4.45 and 8.58 times higher than that of gaseous and liquid fuel alternatives,respectively.In this study,life cycle emission reductions were maximized by a mix of bioenergy end uses based on biomass properties,with an optimal 78.56%bioenergy allocation from biodiesel,densified solid biofuel,biohydrogen,and biochar.The main regional bioenergy GHG mitigation focused on the Jiangsu,Sichuan,Guangxi,Henan,and Guangdong provinces,contributing to 31.32%of the total GHG mitigation potential.This study provides valuable guidance on exploiting untapped biomass resources in China to secure carbon neutrality by 2060.
基金supported by the National Natural Science Foundation of China(Grant No.42006087)the Sugar Crop Research System,China(Grant No.CARS-170501).
文摘Isochrysis galbana is considered an ideal bait for functional foods and nutraceuticals of humans because of its high fucoxanthin(Fx)content.However,multi-omics analysis of the regulatory networks for Fx biosynthesis in I.galbana has not been reported.In this study,we report a high-quality genome assembly of I.galbana LG007,which has a genome size of 92.73 Mb,with a contig N50 of 6.99 Mb and 14,900 protein-coding genes.Phylogenetic analysis confirmed the monophyly of Haptophyta,with I.galbana sister to Emiliania huxleyi and Chrysochromulina tobinii.Evolutionary analysis revealed an estimated divergence time between I.galbana and E.huxleyi of~133 million years ago.Gene family analysis indicated that lipid metabolism-related genes exhibited significant expansion,including IgPLMT,IgOAR1,and IgDEGS1.Metabolome analysis showed that the content of carotenoids in I.galbana cultured under green light for 7 days was higher than that under white light,andβ-carotene was the main carotenoid,accounting for 79.09%of the total carotenoids.Comprehensive multi-omics analysis revealed that the content ofβ-carotene,antheraxanthin,zeaxanthin,and Fx was increased by green light induction,which was significantly correlated with the expression of IgMYB98,IgZDS,IgPDS,IgLHCX2,IgZEP,IgLCYb,and IgNSY.These findings contribute to the understanding of Fx biosynthesis and its regulation,providing a valuable reference for food and pharmaceutical applications.
基金supports of the National Key R&D Program of China(Grant No.2021YFB2600900)National Natural Science Foundation of China(Grant No.52078430)Yunnan Provincial Science and Technology Department of China(Grant No.202002AF080003).
文摘To investigate the compression-shear behavior of a new circumferential joint based on the sleeve-straight bolt combination type connection of large-diameter shield tunnels,a series of full-scale joint experiments was carried out.In the process of the experiment,more attention was paid to the specimen displacement,bolt stress and joint damage mode.On the basis of these experiment phenomena,this study discussed the compression-shear bearing process of the new connector,analyzed the damage mode of the joint structure,and finally evaluated the performance of the new connector.It is found that the bearing process of the joint can be divided into four stages:the transitional stage for overcoming the friction of the concrete,the sleeve bearing stage for the sleeve bearing shear loads alone,the combined bearing stage for bearing shear loads by the connector system,and the structural damage stage for structural instability and damage.Generally speaking,affected by connector position and hand hole,the positive compression-shear stiffness of the joint is less than the negative compression-shear stiffness,and the positive shear strength of the joint is greater than the negative shear strength.The increase of longitudinal axial force will improve the compression-shear performance of the joint.The relationship between longitudinal axial force and joint stiffness is a logarithmic function.The use of new type of connector can effectively improve the compression-shear stiffness of joints under low shear loads,but the application of straight bolts will lose part of the strength performance.
基金financially supported by the National Natural Science Foundation of China (22175104, 21802080 and 21902082)the Natural Science Foundation of Shandong Province (ZR2019ZD47 and ZR2019JQ05)+1 种基金China Postdoctoral Science Foundation (2019M652341)the Education Department of Shandong Province (2019KJC006)。
文摘Synthesis of ultrafine noble metal with sizes down to nanoscale and even atomic scale is of great significance for heterogeneous catalysis. However, the metal loading is usually kept below 2 wt% due to the aggregation tendency at higher metal contents. Herein, by mimicking the multicentered metal sulfur cluster of metalloenzyme, a bioinspired synthesis of isolated noble metal atoms on the metal-organic sulfide(MOS) framework was reported. The sulfur-rich framework featuring [Mo_(3)S_(2)Br_(6)]^(2-) cluster as the building block and dithiol as the linking node was constructed via chemical bonding and employed to support atomic metal species. Remarkably, highly dispersed platinum atoms with a loading amount as high as 18.5 wt% on the underlying sulfurrich framework could be obtained after reduction. By increasing the number of benzene rings in the dithiol, the pore size and even the wettability of the MOS frameworks could be modulated. The general applicability of the synthesis could also be extended to the synthesis of atomic Pd. Furthermore,the Pt-loaded MOS could serve as the catalyst for selective hydrogenation of phenylacetylene to styrene in both organic solvent and pure water. Density function theory calculation demonstrated that the atomic Pt sites in the sulfur-rich coordination environment could activate H_(2) molecules and chemoselectively catalyze the semi-hydrogenation of phenylacetylene to styrene through moderately low energy barriers.The metalation of such a versatile MOS framework will shed light on the synthesis of bioinspired catalytic materials with well-defined structures for more diverse applications.
基金Supported by the Key Research and Development Program of Hunan Province of China(2018GK2031)National Natural Science Foundation of China(51822702)+2 种基金111 Project of China(B17016)Innovative Construction Program of Hunan Province of China(2019RS1016)China Scholarship Council(No.201906130196).
文摘Voltage resonance and fluctuation deteriorate the stability of DC microgrids(DC-MGs)and restrict their popularization.Conventional droop control cannot suppress voltage fluctuation and damp oscillations.Therefore,new control methods,namely,droop+filter control and virtual inertia and damping control,are proposed.These methods differ owing to the addition of low pass filter(LPF)and virtual inertia loop.In this study,the stability of these control methods is investigated comprehensively to understand their differences arising from the use of LPF and inertia loop as well as the underlying dynamic stability mechanism.The leading causes of voltage instability in DC-MGs regulated by droop control are first presented.Subsequently,control methods for solving this issue are compared and their simplified small-signal models are constructed.Based on eigenvalue analysis,the DC-MG is equivalent to a third-order system.Different control effects can be acquired by changing the control parameters and the location of the eigenvalues;furthermore,they can be used to understand the dynamic stability.Eigenvalue analysis can provide parameter design guidelines.Finally,the simulation results verify the validity of the theoretical analysis.
