This study evaluated the antibacterial effects of 2%lidocaine and its combination with 0.9%saline solution on Escherichia coli infection in superficial surgical wounds in Wistar rats.The goal was to determine if these...This study evaluated the antibacterial effects of 2%lidocaine and its combination with 0.9%saline solution on Escherichia coli infection in superficial surgical wounds in Wistar rats.The goal was to determine if these treatments could effectively reduce E.coli Colony Forming Units(CFUs)below the critical threshold of 1×105.Seventy male Wistar rats were divided into seven groups,each undergoing different interventions to assess the antibacterial efficacy of lidocaine,with outcomes measured through bacterial cultures and CFU quantification.Results demonstrated a Log10reduction of approximately 0.44 in E.coli CFUs following infiltration with 2%lidocaine.The combined use of 2%lidocaine infiltration and 0.9%saline irrigation resulted in nearly complete suppression of bacterial growth.These findings suggest that these simple interventions could be valuable in emergency surgical settings to mitigate the risk of surgical site infections and serve as effective prophylactic measures.increase in hospital stay,which represents an additional cost in terms of expenses and directly impacts the patient's outcome.11Several lines of evidence point to 104colony forming units per gram of tissue(CFUs/g)as the threshold at which healing generally begins to slow.12Knowledge of the antibacterial activity of lidocaine has been used to prevent bacterial contamination of other lipid-based anesthetics,such as propofol,with a significant decrease in bacterial development13-15and its antifungal effect.15,16Other effects attributed to lidocaine concerning systemic inflammatory response are the inhibition of granulocyte adhesion at sites of inflammation,decreased leukocyte adhesion during endotoxemia,and decreased macromolecular filtration;it is suggested that it may play a therapeutic role in endothelial damage during sepsis.17-19On the other hand,different measures have been taken to reduce the surgical wound infection rate,such as prophylactic antibiotics and local wound care,including pressure irrigation with 0.9% saline solution,with good results.20The antibacterial effect of lidocaine has been demonstrated in an animal model21;however,no model resembles surgical wound infection and the use of lidocaine to prevent infection.This study aimed to demonstrate that using 2% lidocaine(2 mL/g of tissue)will reduce the E.coli CFUs below 1×105in an infected superficial surgical wound in an experimental model.展开更多
Background:The increasing incidence of cancers and infectious diseases worldwide presents a significant public health challenge that requires immediate intervention.Our strategy to tackle this issue involves the devel...Background:The increasing incidence of cancers and infectious diseases worldwide presents a significant public health challenge that requires immediate intervention.Our strategy to tackle this issue involves the development of pharmaceutical formulations that combine phytopolyphenols(P),targeted drugs(T),and metal ions(M),collectively referred to as PTM regimens.The diverse pharmacological properties of PTM regimens are hypothesized to effectively reduce the risk factors associated with both cancers and infectious diseases.Methods:The effects of the pharmaceutical agents on the proliferation of cultured cancer cells and pathogens were assessed after 72 h and 48 h,respectively,using the MTT(3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide)assay and optical density at 600 nm(OD600).The synergistic effects of drug combinations were evaluated by combination index(CI),where CI<1 indicates synergism,CI=1 indicates addition,and CI>1 indicates antagonism.Efficacy index(EI)was also calculated.Assays of efflux pump ATPase activities were conducted using a colorimetric method.Results:This study evaluated the anticancer and antibacterial efficacy of PTM regimens that included phytopolyphenols(specifically curcumin(C)and green tea polyphenols(G)),repurposed drugs(memantine(Mem),thioridazine(TRZ),cisplatin(Cis),and 5-fluorouracil(5FU)),and ZnSO_(4)(Zn)across three cultured cancer cell lines and four cultured pathogens.The most effective regimens,GC·Mem·Zn and GC·TRZ·Zn,significantly enhanced the anticancer efficacy(EI)of cisplatin across the three cancer lines(OECM-1,A549 and DLD-1)by 7,11 and 21;7,9,and 17 fold,respectively,while the enhancements for 5-fluorouracil were 5,6 and 12;5,5 and 9 fold,respectively.Furthermore,these PTM regimens demonstrated substantial synergistic inhibition of Na^(+)-K^(+)-Mg^(2+)-ATPase and Mg^(2+)-ATPase in the cultured cancer cells,as well as a reduction in biofilm formation by the four cultured pathogens,suggesting their potential to address the challenges of multidrug resistance in cancers and infectious diseases.Conclusion:Given that all drugs incorporated in the PTM regimens have been clinically validated for safety and efficacy,particularly regarding their synergistic selective anticancer efficacy,inhibition of efflux pump ATPase,and antibiofilm formation of pathogens,these regimens may offer a promising therapeutic strategy to alleviate the severe side effects and drug resistance typically associated with chemotherapeutic agents.Further preclinical and clinical investigations are warranted.展开更多
Beam-tracking simulations have been extensively utilized in the study of collective beam instabilities in circular accelerators.Traditionally,many simulation codes have relied on central processing unit(CPU)-based met...Beam-tracking simulations have been extensively utilized in the study of collective beam instabilities in circular accelerators.Traditionally,many simulation codes have relied on central processing unit(CPU)-based methods,tracking on a single CPU core,or parallelizing the computation across multiple cores via the message passing interface(MPI).Although these approaches work well for single-bunch tracking,scaling them to multiple bunches significantly increases the computational load,which often necessitates the use of a dedicated multi-CPU cluster.To address this challenge,alternative methods leveraging General-Purpose computing on Graphics Processing Units(GPGPU)have been proposed,enabling tracking studies on a standalone desktop personal computer(PC).However,frequent CPU-GPU interactions,including data transfers and synchronization operations during tracking,can introduce communication overheads,potentially reducing the overall effectiveness of GPU-based computations.In this study,we propose a novel approach that eliminates this overhead by performing the entire tracking simulation process exclusively on the GPU,thereby enabling the simultaneous processing of all bunches and their macro-particles.Specifically,we introduce MBTRACK2-CUDA,a Compute Unified Device Architecture(CUDA)ported version of MBTRACK2,which facilitates efficient tracking of single-and multi-bunch collective effects by leveraging the full GPU-resident computation.展开更多
Benzalkonium chloride(BAC)is widely employed as a broad-spectrum biocide and has emerged as a significant environmental pollutant.Polymyxin B(PB)serves as the last-line defense for the treatment of Gram-negative patho...Benzalkonium chloride(BAC)is widely employed as a broad-spectrum biocide and has emerged as a significant environmental pollutant.Polymyxin B(PB)serves as the last-line defense for the treatment of Gram-negative pathogens.Previous studies reported that BAC-adapted Pseudomonas aeruginosa increased the tolerance to PB.Herein,we present the novel finding that the combination of BAC and PB exhibited synergistic antibacterial effects against P.aeruginosa.Time-killing assay demonstrated a significant reduction in bacterial cell viability.Scanning electron microscopy,zeta potential analysis,hydrophobicity measurements,and fluorescence probe analyses collectively revealed severe disruption of the cell envelope and membrane potential induced by the combination of BAC and PB.Transcriptomic analysis revealed that the BAC-PB combination notably downreg-ulated the expression of genes involved in lipid A modification and cell envelope production,including phoPQ,pmrAB,bamABCDE,lptABCDEG,lolB,yidC,and murJ.Additionally,the combination group exhibited augmented production of reactive oxygen species and diminished ATP synthesis.The expression of the genes associated with substance metabolism and energy generation was significantly impeded.This study provides significant implica-tions for the interactions of biocides and antibiotics on Gram-negative pathogens,while also addressing antibiotic resistance and developing the external treatment strategy for Pseudomonas-infected wounds and burns.展开更多
In winter 2018,an aerosol physicochemical experiment was conducted in the Western Pacific Ocean(WPO)aboard the Research Vessel KEXUE of Chinese Academy of Sciences.This study systematically investigated both natural a...In winter 2018,an aerosol physicochemical experiment was conducted in the Western Pacific Ocean(WPO)aboard the Research Vessel KEXUE of Chinese Academy of Sciences.This study systematically investigated both natural and anthropogenic effects on marine aerosols optical properties,as well as the applicability of multi-satellite products and IMPROVE equation.The averaged aerosol optical depth(AOD500 nm)was 0.31±0.16 andÅngström exponent440–675 nm was 0.29±0.30.In offshore China,significant anthropogenic emissions affected the marine environment.In remote WPO,dust aerosols transported from northern China,Siberia,Central Asia,and those settling from the upper troposphere originating from north Africa,Arabian peninsula,and western India,were dominant.The spatial trends of AOD were opposite in the mid-latitude and southern seas of WPO.The highest AOD,0.32±0.23,appeared along the coast of South Asia at mid-latitude,decreasing from offshore seas to remote oceans.In low-latitude and equatorial seas,AOD significantly increased from coast to remote oceans.Ångström exponent dropped significantly from the coast to remote oceans as anthropogenic influence diminished across the entire WPO.Correlation analysis showed that both MODIS-C6 and Himawari AOD prod-ucts showed similar applicability in coastal urban areas,while Himawari AOD is highly recommended for coastal background and marine environment due to its finer resolution.The extinction coefficient derived from PM_(2.5) chemical compositions using IMPROVE algorithm exhibited a significant correlation(R^(2)=0.58)with the con-currently measured AOD in the absence of long-distance transport,suggesting that the IMPROVE is a reasonable proxy of the columnar average of marine aerosol extinctions free from transport influences.展开更多
Lithium metal batteries(LMBs)have been regarded as one of the most promising alternatives in the post-lithium battery era due to their high energy density,which meets the needs of light-weight electronic devices and l...Lithium metal batteries(LMBs)have been regarded as one of the most promising alternatives in the post-lithium battery era due to their high energy density,which meets the needs of light-weight electronic devices and long-range electric vehicles.However,technical barriers such as dendrite growth and poor Li plating/stripping reversibility severely hinder the practical application of LMBs.However,lithium nitrate(LiNO_(3))is found to be able to stabilize the Li/electrolyte interface and has been used to address the above challenges.To date,considerable research efforts have been devoted toward understanding the roles of LiNO_(3) in regulating the surface properties of Li anodes and toward the development of many effective strategies.These research efforts are partially mentioned in some articles on LMBs and yet have not been reviewed systematically.To fill this gap,we discuss the recent advances in fundamental and technological research on LiNO_(3) and its derivatives for improving the performances of LMBs,particularly for Li-sulfur(S),Li-oxygen(O),and Li-Li-containing transition-metal oxide(LTMO)batteries,as well as LiNO_(3)-containing recipes for precursors in battery materials and interphase fabrication.This review pays attention to the effects of LiNO_(3) in lithium-based batteries,aiming to provide scientific guidance for the optimization of electrode/electrolyte interfaces and enrich the design of advanced LMBs.展开更多
A1 and N were introduced into copper substrate using plasma immersion ion implantation （PIII） in order to enhance its hardness and oxidation resistance. The dosage of N ion is 5 × 1016 cm-2, and range of dosage...A1 and N were introduced into copper substrate using plasma immersion ion implantation （PIII） in order to enhance its hardness and oxidation resistance. The dosage of N ion is 5 × 1016 cm-2, and range of dosage of A1 ion is 5× 1016-2× 1017 cm-2. The oxidation tests indicate that the copper samples after undergoing PIII possess higher oxidation resistance. The degree of oxidation resistance is found to vary with implantation dosage of AI ion. The antibacterial tests also reveal that the plasma implanted copper specimens have excellent antibacterial resistance against Staphylococcus aureus, which are similar to pure copper.展开更多
[Objective] This study was conducted to investigate the application of nanometallic materials in inhibiting Agrobacteriurn contamination in genetic transformation of Anthurium. [Method] Different nanometallic material...[Objective] This study was conducted to investigate the application of nanometallic materials in inhibiting Agrobacteriurn contamination in genetic transformation of Anthurium. [Method] Different nanometallic materials were added into Agrobacterium medium and Anthurium callus medium, to investigate the effects of their effects on Agrobacterium growth, callus growth and differentiation, and Agrobacterium contamination. [Result] Among the 4 nanometallic materials, NanoAg-2 showed a significant inhibitory effect on the growth of Agrobacterium, with a minimal inhibitory concentration of 25 mg/L. Even for the Anthurium calli or transgenic material contaminated by the Agrobacterium, a good antibacterial effect could be achieved after treating with 25 mg/L NanoAg-2 for 1 d with oscillation, the antibacterial rate reached 100%, and the Anthurium calli could grow and differentiate normally. [Conclusioa] NanoAg-2 could effectively inhibit Agrobacterium contamination, and its an- tibacterial effect is significantly better than cephalosporin and carbenicillin.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
Composites containing nanoparticles of amorphous calcium phosphate （NACP） remineralize tooth lesions and inhibit caries. A recent study synthesized quaternary ammonium methacrylates （QAMs） with chain lengths （CLs...Composites containing nanoparticles of amorphous calcium phosphate （NACP） remineralize tooth lesions and inhibit caries. A recent study synthesized quaternary ammonium methacrylates （QAMs） with chain lengths （CLs） of 3-18 and determined their effects on a bonding agent. This study aimed to incorporate these QAMs into NACP nanocomposites for the first time to simultaneously endow the material with antibacterial and remineralizing capabilities and to investigate the effects of the CL on the mechanical and biofilm properties. Five QAMs were synthesized： DMAPM （CL3）, DMAHM （CL6）, DMADDM （CL12）, DMAHDM （CL16）, and DMAODM （CL18）. Each QAM was incorporated into a composite containing 20% NACP and 50% glass fillers. A dental plaque microcosm biofilm model was used to evaluate the antibacterial activity. The flexural strength and elastic modulus of nanocomposites with QAMs matched those of a commercial control composite （n = 6; P 〉 0.1）. Increasing the CL from 3 to 16 greatly enhanced the antibacterial activity of the NACP nanocomposite （P 〈 0.05）; further increasing the CL to 18 decreased the antibacterial potency. The NACP nanocomposite with a CL of 16 exhibited biofilm metabolic activity and acid production that were 10-fold lesser than those of the control composite. The NACP nanocomposite with a CL of 16 produced 2-log decreases in the colony-forming units （CFU） of total microorganisms, total streptococci, and mutans streptococci. In conclusion, QAMs with CLs of 3-18 were synthesized and incorporated into an NACP nanocomposite for the first time to simultaneously endow the material with antibacterial and remineralization capabilities. Increasing the C/reduced the metabolic activity and acid production of biofilms and caused a 2-log decrease in CFU without compromising the mechanical properties. Nanocomposites exhibiting strong anti-biofilm activity, remineralization effects, and mechanical properties are promising materials for tooth restorations that inhibit caries.展开更多
Polypropylene （PP）/titanium dioxide （TiO2） nano-composites were prepared by melt compounding with a twin screw extruder. Nanoparticles were modified prior to melt mixing with maleic anhydride grafted styreneethyle...Polypropylene （PP）/titanium dioxide （TiO2） nano-composites were prepared by melt compounding with a twin screw extruder. Nanoparticles were modified prior to melt mixing with maleic anhydride grafted styreneethylene-butylene-styrene （SEBS-g-MA） and silane. The composites were injection molded and mechanical tests were applied to obtain tensile strength, elastic modulus and impact strength. Antibacterial efficiency test was applied on the injection molded composite plaques by viable cell counting technique. The results showed that the composites including SEBS-g-MA and silane coated TiO2 gave better mechanical properties than the composites without SEBS-g-MA. Antibacterial efficiency of the composites varied according to the dispersion and the concentration of the particles and it was observed that composites at low content of TiO2 showed higher antibacterial property due to the better photocatalytic activity of the particles during UV exposure.展开更多
[Objectives] To study the antibacterial and antioxidant effects of chlorogenic acid extracts of Gynura procumbens,Lonicera japonica,and Eucommia ulmoides leaves,and provide a reference for their usage as natural food ...[Objectives] To study the antibacterial and antioxidant effects of chlorogenic acid extracts of Gynura procumbens,Lonicera japonica,and Eucommia ulmoides leaves,and provide a reference for their usage as natural food preservatives and antioxidants. [Methods]The disc diffusion method was applied to study the antibacterial activity of chlorogenic acid extracts of G. procumbens,L. japonica,and E. ulmoides leaves against several common pathogens. In the antioxidant effects,study was carried out on the anti-lipid peroxidation,reducing capacity,and DPPH free radical scavenging capacity of chlorogenic acid extracts of G. procumbens,L. japonica,and E. ulmoides leaves,respectively.[Results]Three chlorogenic acid extracts had strong inhibitory effects on bacteria,especially the inhibition on Staphylococcus aureus. At the concentration of 100 mg/m L,the bacteriostatic ring of chlorogenic acid extracts of G. procumbens,L. japonica,and E. ulmoides leaves reached 21. 4,23. 6 and 24. 7 mm respectively. Besides,these chlorogenic acid extracts had significant inhibitory effect on Escherichia coli and Salmonella,but the inhibitory effect on the yeast was not obvious; the antibacterial intensity of antibacterial compounds was chlorogenic acid extracts of E. ulmoides > chlorogenic acid extracts of L. japonica > chlorogenic acid extracts of G. procumbens. Among these three chlorogenic acid extracts,the chlorogenic acid extracts of E. ulmoides had higher anti-lipid peroxidation,reducing capacity,and DPPH free radical scavenging capacity than other two chlorogenic acid extracts. [Conclusions] This paper reveals that among chlorogenic acid extracts of G. procumbens,L. japonica,and E. ulmoides leaves,the chlorogenic acid extracts of E. ulmoides leaves have a stronger antibacterial activity and antioxidant activity.展开更多
AIM:To investigate the antibacterial effects of a crude extract of maggots against Escherichia coli(E.coli) and the underlying mechanisms,and to separate and purifythe crude extract of maggots to assess the antibacter...AIM:To investigate the antibacterial effects of a crude extract of maggots against Escherichia coli(E.coli) and the underlying mechanisms,and to separate and purifythe crude extract of maggots to assess the antibacterial effects of the active ingredients in the crude extract.METHODS:Different concentrations of the crude extract of maggots were incubated with E.coli(O157:H7) and cultured.The optical density(OD) was measured at different time points to plot the OD-T curve.The effects of different concentrations of the crude extract on bacterial membrane permeability were determined by fluorescence probe technique.The effects of different concentrations of the crude extract on plasmid DNA replication were determined by agarose gel electrophoresis.DEAE-Sepharose ion exchange chromatography and Sephacryls-200 HR gel filtration chromatography were used to separate and purify the crude extract of maggots.The molecular weight of proteins in the purified crude extract was determined by SDS-PAGD electrophoresis,and its antibacterial effects were determined by turbidimetric method.RESULTS:The antibacterial effects of the crude extract of maggots at concentrations > 0.5 mg/m L were significant.The antibacterial effects of the crude extract at concentrations of 1.0,1.5 and 2.0 mg/m L did not differ significantly.Fluorescence probe analysis showed that the rate of membrane permeability change was 1223.1% in bacteria incubated with 2 mg/m L of the crude extract,and 1300.0% in those incubated with 80 mg/m L of the crude extract.Plasmid DNA was undetectable in E.coli incubated with 2 and 80 mg/m L of the crude extract.A low molecular weight protein band(about 15 k Da) was detected in the crude extract of maggots and eluent,but not in eluant,from DEAE-Sepharose ion exchange chromatography.The antibacterial effects of the crude extract of maggots and eluent were superior to those of eluant,with the antibacterial effects of eluents being better than those of the crude extract of maggots.Of 24 tubes offiltrates,the antibacterial effects of filtrates in tubes 4,5 and 11 were significantly higher than those of the control.The molecular weight of the protein in filtrates in tubes 4,5 and 11 was about 15 k Da.CONCLUSION:The crude extract of maggots exhibits obvious,dose-dependent antibacterial effects.The crude extract exerts antibacterial effects by changing the bacterial membrane permeability and inhibiting plasmid DNA replication.The prote in that has antibacterial effects in the crude extract of maggots has a molecular weight of about 15 k Da.展开更多
Dynamic changes in mRNA expressions of liver tissue apoptosis-promoting genes Fas and Bax and apoptosis-inhibiting gene Bcl-2 of vibrio vulnificus sepsis rats were detected and the effects of antibacterial agents were...Dynamic changes in mRNA expressions of liver tissue apoptosis-promoting genes Fas and Bax and apoptosis-inhibiting gene Bcl-2 of vibrio vulnificus sepsis rats were detected and the effects of antibacterial agents were examined. The rat model with Vibrio vulnificus sepsis （VV group） was established and some of the Vibrio vulnificus sepsis rats were treated with antibacterial agents （AA group）. The mRNA expressions of Fas, Bax and Bcl-2 were measured by reverse transcription polymerase chain reaction （RT-PCR）. As compared with normal control group （NC group）, the ex- pressions of Fas and Bax mRNA in liver tissue at all different time points in VV group were increased significantly （P〈0.05）, and the highest levels of Fas and Bax mRNA expressions were 6 and 12 h after the infection, respectively. At the same time, the expression of Bcl-2 mRNA in liver tissue at all different time points in VV group were decreased significantly （P〈0.05）, and the lowest level of Bcl-2 mRNA expression appeared 2 h after the infection. The mRNA expressions of Bcl-2 in liver tissue 9 and 12 h after the infection in AA group were increased significantly （P〈0.05） compared with NC group, while the expressions of Fas and Bax mRNA were not significantly different from those of NC group. Compared with VV group, the expression of Fas mRNA in AA group was decreased （P〈0.05） and Bax rnRNA was decreased significantly 12 and 16 h after the infection （P〈0.05）, while the expressions of Bcl-2 mRNA were increased significantly 9, 12 and 16 h after the infection （P〈0.05）. It is concluded that the mRNA expressions of liver tissue apoptosis-promoting genes Fas and Bax were increased remarkably in vibrio vulnificus sepsis rats, whereas the expression of apoptosis-inhibiting gene Bcl-2 mRNA was decreased obviously in sepsis rats in early stage. The treatment with cefoperazone sodium and levofloxacin lactate could inhibit the expression of Fas mRNA and Bax mRNA and enhance the expression ofBcl-2 rnRNA at the same time.展开更多
A series of MgO nanoparticles were prepared by first precipitating and isolating Mg(OH)2 nanoparticles from Mg(NO3)2 at three different temperatures using NaOH followed by their thermal decomposition also at three tem...A series of MgO nanoparticles were prepared by first precipitating and isolating Mg(OH)2 nanoparticles from Mg(NO3)2 at three different temperatures using NaOH followed by their thermal decomposition also at three temperature settings. The effects of temperature at which precipitation and thermal decomposition of the hydroxide occurred were studied to assess their influence on nanoparticle size and surface area. The synthesised nanoparticles were characterized using a suite of techniques including Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), Transmission Electron Microscopy (TEM) and Scanning Electron Microscope (SEM) analysis. The average diameter range of MgO nanoparticles ranged between 15 and 35 nm, while for the precursor Mg(OH)2 it varied between 28 and 45 nm. The nanoparticle surface area obtained from BET studies was found in all cases to increase from 77 to 106.4 m2/g with increasing temperature of precipitation. Antibacterial activities of the prepared Mg(OH)2 and MgO nanoparticles were evaluated against the Gram-negative bacteria, Escherichia coli, and the Gram-positive bacteria, Staphylococcus aureus, using agar diffusion method. A correlation between surface area and antibacterial activity supported the mechanism of bacterial inactivation as the generation of reactive species. The Mg(OH)2 and MgO nanoparticles both exhibited pronounced bactericidal activity towards the Gram positive bacteria than Gram negative bacteria as indicated by the extend of the zone of inhibition around the nanoparticle.展开更多
The effects of antibacterial compounds produced by Saccharomyces cerevisiae in Koumiss on pathogenic Escherichia coli O8 and its cell surface characteristics were investigated.S.cerevisiae isolated from Koumiss produc...The effects of antibacterial compounds produced by Saccharomyces cerevisiae in Koumiss on pathogenic Escherichia coli O8 and its cell surface characteristics were investigated.S.cerevisiae isolated from Koumiss produced antibacterial compounds which were active against pathogenic E.coli O8 as determined by the Oxford cup method.The aqueous phases from S.cerevisiae at p H=2.0（S2）and pH=8.0（S8）were extracted and tested,respectively.The organic acids of S2 and S8 were determined by high performance liquid chromatography（HPLC）,and the concentrations of killer toxins were determined by enhanced bicinchoninic acid（BCA）Protein Assay Kit.The minimum inhibition concentration（MIC）and the minimum bactericidal concentration（MBC）of S2 and S8 on E.coli O8 were determined by the broth microdilution method.The effects of S2 and S8 on the growth curve of E.coli O8 were determined by turbidimetry,and the hydrophobicities of E.coli O8 cell surface were determined using the microbial adhesion to solvents method,the permeation of E.coli O8 cell membrane were determined by the o-nitrophenyl-β-D-galactoside（ONPG）method.Aqueous phases at pH 2.0 and 8.0had larger inhibition zones and then S2 and S8 were obtained by freeze-drying.The main component in S2 was citric acid and it was propanoic acid in S8.Other organic acids and killer toxins were also present.Both the MICs of S2 and S8 on E.coli O8 were 0.025 g m L^-1,the MBCs were 0.100 and 0.200 g m L^-1,respectively.The normal growth curve of E.coli O8was S-shaped,however,it changed after addition of S2 and S8.E.coli O8 was the basic character,and had a relatively hydrophilic surface.The hydrophobicity of E.coli O8 cell surface and the permeation of E.coli O8 cell membrane were increased after adding S2 and S8.The present study showed that S2 and S8 inhibit the growth of pathogenic E.coli O8and influence its cell surface characteristics.展开更多
In order to reduce implant-related infections and improve early osseointegration,we performed HF+anodic oxidation on the surface of the new antibacterial Ti-Cu alloy to make the titanium-based implants have a micro/su...In order to reduce implant-related infections and improve early osseointegration,we performed HF+anodic oxidation on the surface of the new antibacterial Ti-Cu alloy to make the titanium-based implants have a micro/submicron structure.On this basis,a series of surface-modified Ti-x Cu alloys with different Cu contents(3,5 and 7 wt%)were fabricated and a comprehensive study was conducted on MC3 T3-E1 cell adhesion,proliferation,apoptosis and its antibacterial activity against Staphylococcus aureus.Results showed that the Ti-x Cu alloys by HF etching+anodized possessed multifunctional characteristics of antibiofilm and antibacterial abilities,excellent biocompatibility and osteogenesis promoting abilities.Increment of Cu content significantly contributed to the antibacterial and osteogenic properties of HF etching+anodized Ti-Cu alloys.Cell proliferation rates of HF etching+anodized Ti-7 Cu alloys were lower than those of Ti-3 Cu and Ti-5 Cu alloys,while the early cell apoptosis rates were higher than Ti-3 Cu and Ti-5 Cu groups.All the above results finally presented that the HF etching+anodized Ti-5 Cu alloy exhibited extremely strong antibacterial properties,good biological compatibility and osteogenic ability,as well as the most excellent ductility and corrosion resistance,providing a great potential application for the future dental implantation.展开更多
Antibacterial activity of AISI420 stainless steel (SS) implanted by copper was investigated. Ions extracted from a metal vapor vacuum arc (MEVVA) are sourced with 100keV energy and a dose range from 0.2×1017 to 2...Antibacterial activity of AISI420 stainless steel (SS) implanted by copper was investigated. Ions extracted from a metal vapor vacuum arc (MEVVA) are sourced with 100keV energy and a dose range from 0.2×1017 to 2.0×1017ions·cm-2. The saturation dose of Cu implantation in AISI420 SS and Cu surface concentration were calculated at the energy of 100keV. The effect of dose on the antibacterial activity was analyzed. Results of antibacterial test show that the saturation dose is the optimum implantation dose for best antibacterial activity, which is above 99% against both Escherichia coli and Staphylococcus aureus. Novel phases such as Fe4Cu3 and Cu9.9Fe0.1 were found in the implanted layer by glancing angle X-ray diffraction (GXRD). The antibacterial activity of AISI420 SS attributes to Cu-contained phase.展开更多
Irrational antibiotics/antibacterial (AB) drug use is a global problem, especially in developing countries. This results in an increased emergence of resistance to most common bacteria, higher cost of treatment, prolo...Irrational antibiotics/antibacterial (AB) drug use is a global problem, especially in developing countries. This results in an increased emergence of resistance to most common bacteria, higher cost of treatment, prolonged hospitalization and adverse drug reactions. Interventions measures have been instituted to avert the problem but it still persists. A systematic review was conducted to determine the effect of different interventions (education, managerial, diagnostic tests, regulatory, economic and multifaceted) on misuse of AB drugs in developing countries. A total of 722 articles were retrieved and 55 were reviewed. About 10.9% of the studies were from Africa, 63.6% from Asia, 9.1% from Latin America, and 16.4% from Southeastern Europe. A total of 52.7% of the studies were from hospital settings, 5.5% from outpatient departments, 21.8% were from public health care facilities, 12.7% from private pharmacies/drug stores, and 7.3% from the communities. Education intervention had 27.3% studies, managerial had 20%, managerial/education had 3.6%, regulatory had 9.1%, education/regulation had 9.1% and diagnostic had 3.6% studies. Multifaceted intervention had 27.3% studies, with 63% improvement in appropriate AB doses prescribed, 2.6% mean number of AB encounter reduction, 23% AB prescription reduction, 18.3% generic AB prescription improvement, 32.1% reduction in AB use, 89% reduction in AB use in acute respiratory infection, 82% in surgery, 62.7% mean reduction in deliveries, 39% in STDs, 36.3% mean reduction in diarrhea, 14.6% mean reduction AB use in malaria, and 6%-11% in the cost of treating bacteria-resistant organisms. Also noted was 6.3% reductions in mean AB encounters after 1 month of intervention, and then increased to 7.7% after 3 months thus lacking sustainability. Multifaceted interventions were effective in reducing irrational AB drug use in the various health facilities and communities as well as reduction in the emergence of resistance to the commonest bacteria in the developing countries though there was lack of sustainability or continuity of rational drug use over the time.展开更多
A type of antibacterial bacterial cellulose(BC) film was prepared for potential uses as wound dressing.In order to obtain a high antibacterial effect,some forms of BC films,including the wet and dried ones were utiliz...A type of antibacterial bacterial cellulose(BC) film was prepared for potential uses as wound dressing.In order to obtain a high antibacterial effect,some forms of BC films,including the wet and dried ones were utilized as the template to in situ synthesize silver nanoparticles(AgNPs).The effects of drying methods including freeze-drying,heat drying and air drying,on the microstructures and physical properties of BC,as well as the silver contents and the antibacterial performances of the BC/AgNPs composites were investigated.It was found that the AgNPs impregnated on the dried BC films were inclined to achieve a faster silver releasing rate than the wet one,which was suitable for acute traumas treatment.展开更多
文摘This study evaluated the antibacterial effects of 2%lidocaine and its combination with 0.9%saline solution on Escherichia coli infection in superficial surgical wounds in Wistar rats.The goal was to determine if these treatments could effectively reduce E.coli Colony Forming Units(CFUs)below the critical threshold of 1×105.Seventy male Wistar rats were divided into seven groups,each undergoing different interventions to assess the antibacterial efficacy of lidocaine,with outcomes measured through bacterial cultures and CFU quantification.Results demonstrated a Log10reduction of approximately 0.44 in E.coli CFUs following infiltration with 2%lidocaine.The combined use of 2%lidocaine infiltration and 0.9%saline irrigation resulted in nearly complete suppression of bacterial growth.These findings suggest that these simple interventions could be valuable in emergency surgical settings to mitigate the risk of surgical site infections and serve as effective prophylactic measures.increase in hospital stay,which represents an additional cost in terms of expenses and directly impacts the patient's outcome.11Several lines of evidence point to 104colony forming units per gram of tissue(CFUs/g)as the threshold at which healing generally begins to slow.12Knowledge of the antibacterial activity of lidocaine has been used to prevent bacterial contamination of other lipid-based anesthetics,such as propofol,with a significant decrease in bacterial development13-15and its antifungal effect.15,16Other effects attributed to lidocaine concerning systemic inflammatory response are the inhibition of granulocyte adhesion at sites of inflammation,decreased leukocyte adhesion during endotoxemia,and decreased macromolecular filtration;it is suggested that it may play a therapeutic role in endothelial damage during sepsis.17-19On the other hand,different measures have been taken to reduce the surgical wound infection rate,such as prophylactic antibiotics and local wound care,including pressure irrigation with 0.9% saline solution,with good results.20The antibacterial effect of lidocaine has been demonstrated in an animal model21;however,no model resembles surgical wound infection and the use of lidocaine to prevent infection.This study aimed to demonstrate that using 2% lidocaine(2 mL/g of tissue)will reduce the E.coli CFUs below 1×105in an infected superficial surgical wound in an experimental model.
文摘Background:The increasing incidence of cancers and infectious diseases worldwide presents a significant public health challenge that requires immediate intervention.Our strategy to tackle this issue involves the development of pharmaceutical formulations that combine phytopolyphenols(P),targeted drugs(T),and metal ions(M),collectively referred to as PTM regimens.The diverse pharmacological properties of PTM regimens are hypothesized to effectively reduce the risk factors associated with both cancers and infectious diseases.Methods:The effects of the pharmaceutical agents on the proliferation of cultured cancer cells and pathogens were assessed after 72 h and 48 h,respectively,using the MTT(3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide)assay and optical density at 600 nm(OD600).The synergistic effects of drug combinations were evaluated by combination index(CI),where CI<1 indicates synergism,CI=1 indicates addition,and CI>1 indicates antagonism.Efficacy index(EI)was also calculated.Assays of efflux pump ATPase activities were conducted using a colorimetric method.Results:This study evaluated the anticancer and antibacterial efficacy of PTM regimens that included phytopolyphenols(specifically curcumin(C)and green tea polyphenols(G)),repurposed drugs(memantine(Mem),thioridazine(TRZ),cisplatin(Cis),and 5-fluorouracil(5FU)),and ZnSO_(4)(Zn)across three cultured cancer cell lines and four cultured pathogens.The most effective regimens,GC·Mem·Zn and GC·TRZ·Zn,significantly enhanced the anticancer efficacy(EI)of cisplatin across the three cancer lines(OECM-1,A549 and DLD-1)by 7,11 and 21;7,9,and 17 fold,respectively,while the enhancements for 5-fluorouracil were 5,6 and 12;5,5 and 9 fold,respectively.Furthermore,these PTM regimens demonstrated substantial synergistic inhibition of Na^(+)-K^(+)-Mg^(2+)-ATPase and Mg^(2+)-ATPase in the cultured cancer cells,as well as a reduction in biofilm formation by the four cultured pathogens,suggesting their potential to address the challenges of multidrug resistance in cancers and infectious diseases.Conclusion:Given that all drugs incorporated in the PTM regimens have been clinically validated for safety and efficacy,particularly regarding their synergistic selective anticancer efficacy,inhibition of efflux pump ATPase,and antibiofilm formation of pathogens,these regimens may offer a promising therapeutic strategy to alleviate the severe side effects and drug resistance typically associated with chemotherapeutic agents.Further preclinical and clinical investigations are warranted.
基金supported by the National Research Foundation of Korea(NRF)funded by the Ministry of Science and ICT(MSIT)(No.RS-2022-00143178)the Ministry of Education(MOE)(Nos.2022R1A6A3A13053896 and 2022R1F1A1074616),Republic of Korea.
文摘Beam-tracking simulations have been extensively utilized in the study of collective beam instabilities in circular accelerators.Traditionally,many simulation codes have relied on central processing unit(CPU)-based methods,tracking on a single CPU core,or parallelizing the computation across multiple cores via the message passing interface(MPI).Although these approaches work well for single-bunch tracking,scaling them to multiple bunches significantly increases the computational load,which often necessitates the use of a dedicated multi-CPU cluster.To address this challenge,alternative methods leveraging General-Purpose computing on Graphics Processing Units(GPGPU)have been proposed,enabling tracking studies on a standalone desktop personal computer(PC).However,frequent CPU-GPU interactions,including data transfers and synchronization operations during tracking,can introduce communication overheads,potentially reducing the overall effectiveness of GPU-based computations.In this study,we propose a novel approach that eliminates this overhead by performing the entire tracking simulation process exclusively on the GPU,thereby enabling the simultaneous processing of all bunches and their macro-particles.Specifically,we introduce MBTRACK2-CUDA,a Compute Unified Device Architecture(CUDA)ported version of MBTRACK2,which facilitates efficient tracking of single-and multi-bunch collective effects by leveraging the full GPU-resident computation.
基金supported by the National Natural Science Foundation of China(No.32170121).
文摘Benzalkonium chloride(BAC)is widely employed as a broad-spectrum biocide and has emerged as a significant environmental pollutant.Polymyxin B(PB)serves as the last-line defense for the treatment of Gram-negative pathogens.Previous studies reported that BAC-adapted Pseudomonas aeruginosa increased the tolerance to PB.Herein,we present the novel finding that the combination of BAC and PB exhibited synergistic antibacterial effects against P.aeruginosa.Time-killing assay demonstrated a significant reduction in bacterial cell viability.Scanning electron microscopy,zeta potential analysis,hydrophobicity measurements,and fluorescence probe analyses collectively revealed severe disruption of the cell envelope and membrane potential induced by the combination of BAC and PB.Transcriptomic analysis revealed that the BAC-PB combination notably downreg-ulated the expression of genes involved in lipid A modification and cell envelope production,including phoPQ,pmrAB,bamABCDE,lptABCDEG,lolB,yidC,and murJ.Additionally,the combination group exhibited augmented production of reactive oxygen species and diminished ATP synthesis.The expression of the genes associated with substance metabolism and energy generation was significantly impeded.This study provides significant implica-tions for the interactions of biocides and antibiotics on Gram-negative pathogens,while also addressing antibiotic resistance and developing the external treatment strategy for Pseudomonas-infected wounds and burns.
基金supported by the CAS Strategic Priority Research Program(No.XDB0760102),the Ministry of Science and Technology of China(No.2022YFF0802501)the Major Science and Technology Infrastructure Maintenance and Transformation Project of the Chinese Academy of Sciences,Shanghai Science and Technology Innovation Action Plan-Phospherus Project(No.23YF1426200)the National Key Research and Development Program of China(No.2024YFE0212200).
文摘In winter 2018,an aerosol physicochemical experiment was conducted in the Western Pacific Ocean(WPO)aboard the Research Vessel KEXUE of Chinese Academy of Sciences.This study systematically investigated both natural and anthropogenic effects on marine aerosols optical properties,as well as the applicability of multi-satellite products and IMPROVE equation.The averaged aerosol optical depth(AOD500 nm)was 0.31±0.16 andÅngström exponent440–675 nm was 0.29±0.30.In offshore China,significant anthropogenic emissions affected the marine environment.In remote WPO,dust aerosols transported from northern China,Siberia,Central Asia,and those settling from the upper troposphere originating from north Africa,Arabian peninsula,and western India,were dominant.The spatial trends of AOD were opposite in the mid-latitude and southern seas of WPO.The highest AOD,0.32±0.23,appeared along the coast of South Asia at mid-latitude,decreasing from offshore seas to remote oceans.In low-latitude and equatorial seas,AOD significantly increased from coast to remote oceans.Ångström exponent dropped significantly from the coast to remote oceans as anthropogenic influence diminished across the entire WPO.Correlation analysis showed that both MODIS-C6 and Himawari AOD prod-ucts showed similar applicability in coastal urban areas,while Himawari AOD is highly recommended for coastal background and marine environment due to its finer resolution.The extinction coefficient derived from PM_(2.5) chemical compositions using IMPROVE algorithm exhibited a significant correlation(R^(2)=0.58)with the con-currently measured AOD in the absence of long-distance transport,suggesting that the IMPROVE is a reasonable proxy of the columnar average of marine aerosol extinctions free from transport influences.
基金supported by the Yunnan Fundamental Research Projects(Grant Nos.202401AU070163 and 202501AT070298)the Yunnan Engineering Research Center Innovation Ability Construction and Enhancement Projects(Grant No.2023-XMDJ-00617107)+5 种基金the University Service Key Industry Project of Yunnan Province(Grant No.FWCY-ZD2024005)the Expert Workstation Support Project of Yunnan Province(Grant No.202405AF140069)the Scientific Research Foundation of Kunming University of Science and Technology(Grant No.20220122)the Analysis and Test Foundation of Kunming University of Science and Technology(Grant No.2023T20220122)the Natural Science Foundation of Inner Mongolia Autonomous Region of China(Grant No.2025QN02057)the Ordos City Strategic Pioneering Science and Technology Special Program for New Energy(Grant No.DC2400003365).
文摘Lithium metal batteries(LMBs)have been regarded as one of the most promising alternatives in the post-lithium battery era due to their high energy density,which meets the needs of light-weight electronic devices and long-range electric vehicles.However,technical barriers such as dendrite growth and poor Li plating/stripping reversibility severely hinder the practical application of LMBs.However,lithium nitrate(LiNO_(3))is found to be able to stabilize the Li/electrolyte interface and has been used to address the above challenges.To date,considerable research efforts have been devoted toward understanding the roles of LiNO_(3) in regulating the surface properties of Li anodes and toward the development of many effective strategies.These research efforts are partially mentioned in some articles on LMBs and yet have not been reviewed systematically.To fill this gap,we discuss the recent advances in fundamental and technological research on LiNO_(3) and its derivatives for improving the performances of LMBs,particularly for Li-sulfur(S),Li-oxygen(O),and Li-Li-containing transition-metal oxide(LTMO)batteries,as well as LiNO_(3)-containing recipes for precursors in battery materials and interphase fabrication.This review pays attention to the effects of LiNO_(3) in lithium-based batteries,aiming to provide scientific guidance for the optimization of electrode/electrolyte interfaces and enrich the design of advanced LMBs.
基金Project(9231083) supported by Yunnan Aerospace Industry Corporation Contract Research,ChinaProject(9220061) supported by City University of Hong Kong Donation Research Grant,China
文摘A1 and N were introduced into copper substrate using plasma immersion ion implantation （PIII） in order to enhance its hardness and oxidation resistance. The dosage of N ion is 5 × 1016 cm-2, and range of dosage of A1 ion is 5× 1016-2× 1017 cm-2. The oxidation tests indicate that the copper samples after undergoing PIII possess higher oxidation resistance. The degree of oxidation resistance is found to vary with implantation dosage of AI ion. The antibacterial tests also reveal that the plasma implanted copper specimens have excellent antibacterial resistance against Staphylococcus aureus, which are similar to pure copper.
文摘[Objective] This study was conducted to investigate the application of nanometallic materials in inhibiting Agrobacteriurn contamination in genetic transformation of Anthurium. [Method] Different nanometallic materials were added into Agrobacterium medium and Anthurium callus medium, to investigate the effects of their effects on Agrobacterium growth, callus growth and differentiation, and Agrobacterium contamination. [Result] Among the 4 nanometallic materials, NanoAg-2 showed a significant inhibitory effect on the growth of Agrobacterium, with a minimal inhibitory concentration of 25 mg/L. Even for the Anthurium calli or transgenic material contaminated by the Agrobacterium, a good antibacterial effect could be achieved after treating with 25 mg/L NanoAg-2 for 1 d with oscillation, the antibacterial rate reached 100%, and the Anthurium calli could grow and differentiate normally. [Conclusioa] NanoAg-2 could effectively inhibit Agrobacterium contamination, and its an- tibacterial effect is significantly better than cephalosporin and carbenicillin.
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 National Institutes of Health (NIH) R01DE17974 (Hockin HK Xu)National Natural Science Foundation of China grant 81400540 (Ke Zhang)a seed fund (Hockin HK Xu) from the University of Maryland School of Dentistry
文摘Composites containing nanoparticles of amorphous calcium phosphate （NACP） remineralize tooth lesions and inhibit caries. A recent study synthesized quaternary ammonium methacrylates （QAMs） with chain lengths （CLs） of 3-18 and determined their effects on a bonding agent. This study aimed to incorporate these QAMs into NACP nanocomposites for the first time to simultaneously endow the material with antibacterial and remineralizing capabilities and to investigate the effects of the CL on the mechanical and biofilm properties. Five QAMs were synthesized： DMAPM （CL3）, DMAHM （CL6）, DMADDM （CL12）, DMAHDM （CL16）, and DMAODM （CL18）. Each QAM was incorporated into a composite containing 20% NACP and 50% glass fillers. A dental plaque microcosm biofilm model was used to evaluate the antibacterial activity. The flexural strength and elastic modulus of nanocomposites with QAMs matched those of a commercial control composite （n = 6; P 〉 0.1）. Increasing the CL from 3 to 16 greatly enhanced the antibacterial activity of the NACP nanocomposite （P 〈 0.05）; further increasing the CL to 18 decreased the antibacterial potency. The NACP nanocomposite with a CL of 16 exhibited biofilm metabolic activity and acid production that were 10-fold lesser than those of the control composite. The NACP nanocomposite with a CL of 16 produced 2-log decreases in the colony-forming units （CFU） of total microorganisms, total streptococci, and mutans streptococci. In conclusion, QAMs with CLs of 3-18 were synthesized and incorporated into an NACP nanocomposite for the first time to simultaneously endow the material with antibacterial and remineralization capabilities. Increasing the C/reduced the metabolic activity and acid production of biofilms and caused a 2-log decrease in CFU without compromising the mechanical properties. Nanocomposites exhibiting strong anti-biofilm activity, remineralization effects, and mechanical properties are promising materials for tooth restorations that inhibit caries.
基金supported by the Scientific and Technological Research Council of Turkey (TUBITAK, Project No. 108M561)
文摘Polypropylene （PP）/titanium dioxide （TiO2） nano-composites were prepared by melt compounding with a twin screw extruder. Nanoparticles were modified prior to melt mixing with maleic anhydride grafted styreneethylene-butylene-styrene （SEBS-g-MA） and silane. The composites were injection molded and mechanical tests were applied to obtain tensile strength, elastic modulus and impact strength. Antibacterial efficiency test was applied on the injection molded composite plaques by viable cell counting technique. The results showed that the composites including SEBS-g-MA and silane coated TiO2 gave better mechanical properties than the composites without SEBS-g-MA. Antibacterial efficiency of the composites varied according to the dispersion and the concentration of the particles and it was observed that composites at low content of TiO2 showed higher antibacterial property due to the better photocatalytic activity of the particles during UV exposure.
基金Supported by Key Science and Technology Project of Jiangxi Province(2017ACF60009)Key Project of Jiangxi Academy of Sciences(2016-YZDZ-03)
文摘[Objectives] To study the antibacterial and antioxidant effects of chlorogenic acid extracts of Gynura procumbens,Lonicera japonica,and Eucommia ulmoides leaves,and provide a reference for their usage as natural food preservatives and antioxidants. [Methods]The disc diffusion method was applied to study the antibacterial activity of chlorogenic acid extracts of G. procumbens,L. japonica,and E. ulmoides leaves against several common pathogens. In the antioxidant effects,study was carried out on the anti-lipid peroxidation,reducing capacity,and DPPH free radical scavenging capacity of chlorogenic acid extracts of G. procumbens,L. japonica,and E. ulmoides leaves,respectively.[Results]Three chlorogenic acid extracts had strong inhibitory effects on bacteria,especially the inhibition on Staphylococcus aureus. At the concentration of 100 mg/m L,the bacteriostatic ring of chlorogenic acid extracts of G. procumbens,L. japonica,and E. ulmoides leaves reached 21. 4,23. 6 and 24. 7 mm respectively. Besides,these chlorogenic acid extracts had significant inhibitory effect on Escherichia coli and Salmonella,but the inhibitory effect on the yeast was not obvious; the antibacterial intensity of antibacterial compounds was chlorogenic acid extracts of E. ulmoides > chlorogenic acid extracts of L. japonica > chlorogenic acid extracts of G. procumbens. Among these three chlorogenic acid extracts,the chlorogenic acid extracts of E. ulmoides had higher anti-lipid peroxidation,reducing capacity,and DPPH free radical scavenging capacity than other two chlorogenic acid extracts. [Conclusions] This paper reveals that among chlorogenic acid extracts of G. procumbens,L. japonica,and E. ulmoides leaves,the chlorogenic acid extracts of E. ulmoides leaves have a stronger antibacterial activity and antioxidant activity.
基金Supported by National Natural Science Foundation of China,No.81270052
文摘AIM:To investigate the antibacterial effects of a crude extract of maggots against Escherichia coli(E.coli) and the underlying mechanisms,and to separate and purifythe crude extract of maggots to assess the antibacterial effects of the active ingredients in the crude extract.METHODS:Different concentrations of the crude extract of maggots were incubated with E.coli(O157:H7) and cultured.The optical density(OD) was measured at different time points to plot the OD-T curve.The effects of different concentrations of the crude extract on bacterial membrane permeability were determined by fluorescence probe technique.The effects of different concentrations of the crude extract on plasmid DNA replication were determined by agarose gel electrophoresis.DEAE-Sepharose ion exchange chromatography and Sephacryls-200 HR gel filtration chromatography were used to separate and purify the crude extract of maggots.The molecular weight of proteins in the purified crude extract was determined by SDS-PAGD electrophoresis,and its antibacterial effects were determined by turbidimetric method.RESULTS:The antibacterial effects of the crude extract of maggots at concentrations > 0.5 mg/m L were significant.The antibacterial effects of the crude extract at concentrations of 1.0,1.5 and 2.0 mg/m L did not differ significantly.Fluorescence probe analysis showed that the rate of membrane permeability change was 1223.1% in bacteria incubated with 2 mg/m L of the crude extract,and 1300.0% in those incubated with 80 mg/m L of the crude extract.Plasmid DNA was undetectable in E.coli incubated with 2 and 80 mg/m L of the crude extract.A low molecular weight protein band(about 15 k Da) was detected in the crude extract of maggots and eluent,but not in eluant,from DEAE-Sepharose ion exchange chromatography.The antibacterial effects of the crude extract of maggots and eluent were superior to those of eluant,with the antibacterial effects of eluents being better than those of the crude extract of maggots.Of 24 tubes offiltrates,the antibacterial effects of filtrates in tubes 4,5 and 11 were significantly higher than those of the control.The molecular weight of the protein in filtrates in tubes 4,5 and 11 was about 15 k Da.CONCLUSION:The crude extract of maggots exhibits obvious,dose-dependent antibacterial effects.The crude extract exerts antibacterial effects by changing the bacterial membrane permeability and inhibiting plasmid DNA replication.The prote in that has antibacterial effects in the crude extract of maggots has a molecular weight of about 15 k Da.
基金supported by a grant for supporting key research programs from Zhejiang Province (No.07-F04)a Science and Technology Fund of Zhejiang Province (No.2005C30009)
文摘Dynamic changes in mRNA expressions of liver tissue apoptosis-promoting genes Fas and Bax and apoptosis-inhibiting gene Bcl-2 of vibrio vulnificus sepsis rats were detected and the effects of antibacterial agents were examined. The rat model with Vibrio vulnificus sepsis （VV group） was established and some of the Vibrio vulnificus sepsis rats were treated with antibacterial agents （AA group）. The mRNA expressions of Fas, Bax and Bcl-2 were measured by reverse transcription polymerase chain reaction （RT-PCR）. As compared with normal control group （NC group）, the ex- pressions of Fas and Bax mRNA in liver tissue at all different time points in VV group were increased significantly （P〈0.05）, and the highest levels of Fas and Bax mRNA expressions were 6 and 12 h after the infection, respectively. At the same time, the expression of Bcl-2 mRNA in liver tissue at all different time points in VV group were decreased significantly （P〈0.05）, and the lowest level of Bcl-2 mRNA expression appeared 2 h after the infection. The mRNA expressions of Bcl-2 in liver tissue 9 and 12 h after the infection in AA group were increased significantly （P〈0.05） compared with NC group, while the expressions of Fas and Bax mRNA were not significantly different from those of NC group. Compared with VV group, the expression of Fas mRNA in AA group was decreased （P〈0.05） and Bax rnRNA was decreased significantly 12 and 16 h after the infection （P〈0.05）, while the expressions of Bcl-2 mRNA were increased significantly 9, 12 and 16 h after the infection （P〈0.05）. It is concluded that the mRNA expressions of liver tissue apoptosis-promoting genes Fas and Bax were increased remarkably in vibrio vulnificus sepsis rats, whereas the expression of apoptosis-inhibiting gene Bcl-2 mRNA was decreased obviously in sepsis rats in early stage. The treatment with cefoperazone sodium and levofloxacin lactate could inhibit the expression of Fas mRNA and Bax mRNA and enhance the expression ofBcl-2 rnRNA at the same time.
文摘A series of MgO nanoparticles were prepared by first precipitating and isolating Mg(OH)2 nanoparticles from Mg(NO3)2 at three different temperatures using NaOH followed by their thermal decomposition also at three temperature settings. The effects of temperature at which precipitation and thermal decomposition of the hydroxide occurred were studied to assess their influence on nanoparticle size and surface area. The synthesised nanoparticles were characterized using a suite of techniques including Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), Transmission Electron Microscopy (TEM) and Scanning Electron Microscope (SEM) analysis. The average diameter range of MgO nanoparticles ranged between 15 and 35 nm, while for the precursor Mg(OH)2 it varied between 28 and 45 nm. The nanoparticle surface area obtained from BET studies was found in all cases to increase from 77 to 106.4 m2/g with increasing temperature of precipitation. Antibacterial activities of the prepared Mg(OH)2 and MgO nanoparticles were evaluated against the Gram-negative bacteria, Escherichia coli, and the Gram-positive bacteria, Staphylococcus aureus, using agar diffusion method. A correlation between surface area and antibacterial activity supported the mechanism of bacterial inactivation as the generation of reactive species. The Mg(OH)2 and MgO nanoparticles both exhibited pronounced bactericidal activity towards the Gram positive bacteria than Gram negative bacteria as indicated by the extend of the zone of inhibition around the nanoparticle.
基金supported by the National Natural Science Funds, China (31260570, 31260590, 31060318)the National Key Technologies R&D Program (2012BAD12B09-3)the Innovation Projects of Inner Mongolia Graduate Education, China (B20141012911)
文摘The effects of antibacterial compounds produced by Saccharomyces cerevisiae in Koumiss on pathogenic Escherichia coli O8 and its cell surface characteristics were investigated.S.cerevisiae isolated from Koumiss produced antibacterial compounds which were active against pathogenic E.coli O8 as determined by the Oxford cup method.The aqueous phases from S.cerevisiae at p H=2.0（S2）and pH=8.0（S8）were extracted and tested,respectively.The organic acids of S2 and S8 were determined by high performance liquid chromatography（HPLC）,and the concentrations of killer toxins were determined by enhanced bicinchoninic acid（BCA）Protein Assay Kit.The minimum inhibition concentration（MIC）and the minimum bactericidal concentration（MBC）of S2 and S8 on E.coli O8 were determined by the broth microdilution method.The effects of S2 and S8 on the growth curve of E.coli O8 were determined by turbidimetry,and the hydrophobicities of E.coli O8 cell surface were determined using the microbial adhesion to solvents method,the permeation of E.coli O8 cell membrane were determined by the o-nitrophenyl-β-D-galactoside（ONPG）method.Aqueous phases at pH 2.0 and 8.0had larger inhibition zones and then S2 and S8 were obtained by freeze-drying.The main component in S2 was citric acid and it was propanoic acid in S8.Other organic acids and killer toxins were also present.Both the MICs of S2 and S8 on E.coli O8 were 0.025 g m L^-1,the MBCs were 0.100 and 0.200 g m L^-1,respectively.The normal growth curve of E.coli O8was S-shaped,however,it changed after addition of S2 and S8.E.coli O8 was the basic character,and had a relatively hydrophilic surface.The hydrophobicity of E.coli O8 cell surface and the permeation of E.coli O8 cell membrane were increased after adding S2 and S8.The present study showed that S2 and S8 inhibit the growth of pathogenic E.coli O8and influence its cell surface characteristics.
基金financially supported by the National Key Research and Development Program of China(Nos.2018YFC1106601 and 2016YFC1100601)the LiaoNing Revitalization Talents Program(No.XLYC1807069)+1 种基金the National Natural Science Foundation of China(Nos.51631009 and 31870954)the Key Projects for Foreign Cooperation of Bureau of International Cooperation Chinese Academy of Sciences(No.174321KYSB2018000)。
文摘In order to reduce implant-related infections and improve early osseointegration,we performed HF+anodic oxidation on the surface of the new antibacterial Ti-Cu alloy to make the titanium-based implants have a micro/submicron structure.On this basis,a series of surface-modified Ti-x Cu alloys with different Cu contents(3,5 and 7 wt%)were fabricated and a comprehensive study was conducted on MC3 T3-E1 cell adhesion,proliferation,apoptosis and its antibacterial activity against Staphylococcus aureus.Results showed that the Ti-x Cu alloys by HF etching+anodized possessed multifunctional characteristics of antibiofilm and antibacterial abilities,excellent biocompatibility and osteogenesis promoting abilities.Increment of Cu content significantly contributed to the antibacterial and osteogenic properties of HF etching+anodized Ti-Cu alloys.Cell proliferation rates of HF etching+anodized Ti-7 Cu alloys were lower than those of Ti-3 Cu and Ti-5 Cu alloys,while the early cell apoptosis rates were higher than Ti-3 Cu and Ti-5 Cu groups.All the above results finally presented that the HF etching+anodized Ti-5 Cu alloy exhibited extremely strong antibacterial properties,good biological compatibility and osteogenic ability,as well as the most excellent ductility and corrosion resistance,providing a great potential application for the future dental implantation.
基金This work was supported by the National Natural Science Foundation of China(No.50101009)
文摘Antibacterial activity of AISI420 stainless steel (SS) implanted by copper was investigated. Ions extracted from a metal vapor vacuum arc (MEVVA) are sourced with 100keV energy and a dose range from 0.2×1017 to 2.0×1017ions·cm-2. The saturation dose of Cu implantation in AISI420 SS and Cu surface concentration were calculated at the energy of 100keV. The effect of dose on the antibacterial activity was analyzed. Results of antibacterial test show that the saturation dose is the optimum implantation dose for best antibacterial activity, which is above 99% against both Escherichia coli and Staphylococcus aureus. Novel phases such as Fe4Cu3 and Cu9.9Fe0.1 were found in the implanted layer by glancing angle X-ray diffraction (GXRD). The antibacterial activity of AISI420 SS attributes to Cu-contained phase.
文摘Irrational antibiotics/antibacterial (AB) drug use is a global problem, especially in developing countries. This results in an increased emergence of resistance to most common bacteria, higher cost of treatment, prolonged hospitalization and adverse drug reactions. Interventions measures have been instituted to avert the problem but it still persists. A systematic review was conducted to determine the effect of different interventions (education, managerial, diagnostic tests, regulatory, economic and multifaceted) on misuse of AB drugs in developing countries. A total of 722 articles were retrieved and 55 were reviewed. About 10.9% of the studies were from Africa, 63.6% from Asia, 9.1% from Latin America, and 16.4% from Southeastern Europe. A total of 52.7% of the studies were from hospital settings, 5.5% from outpatient departments, 21.8% were from public health care facilities, 12.7% from private pharmacies/drug stores, and 7.3% from the communities. Education intervention had 27.3% studies, managerial had 20%, managerial/education had 3.6%, regulatory had 9.1%, education/regulation had 9.1% and diagnostic had 3.6% studies. Multifaceted intervention had 27.3% studies, with 63% improvement in appropriate AB doses prescribed, 2.6% mean number of AB encounter reduction, 23% AB prescription reduction, 18.3% generic AB prescription improvement, 32.1% reduction in AB use, 89% reduction in AB use in acute respiratory infection, 82% in surgery, 62.7% mean reduction in deliveries, 39% in STDs, 36.3% mean reduction in diarrhea, 14.6% mean reduction AB use in malaria, and 6%-11% in the cost of treating bacteria-resistant organisms. Also noted was 6.3% reductions in mean AB encounters after 1 month of intervention, and then increased to 7.7% after 3 months thus lacking sustainability. Multifaceted interventions were effective in reducing irrational AB drug use in the various health facilities and communities as well as reduction in the emergence of resistance to the commonest bacteria in the developing countries though there was lack of sustainability or continuity of rational drug use over the time.
基金“111 Project” Biomedical Textile Materials Science and Technology,China(No.B07024)Natural Science Foundation of Shanghai,China(No.15ZR1401000)the Fundamental Research Funds for the Central Universities,China
文摘A type of antibacterial bacterial cellulose(BC) film was prepared for potential uses as wound dressing.In order to obtain a high antibacterial effect,some forms of BC films,including the wet and dried ones were utilized as the template to in situ synthesize silver nanoparticles(AgNPs).The effects of drying methods including freeze-drying,heat drying and air drying,on the microstructures and physical properties of BC,as well as the silver contents and the antibacterial performances of the BC/AgNPs composites were investigated.It was found that the AgNPs impregnated on the dried BC films were inclined to achieve a faster silver releasing rate than the wet one,which was suitable for acute traumas treatment.
