Two Gd_(2)complexes,namely[Gd_(2)(dbm)_(2)(HL_(1))_(2)(CH_(3)OH)_(2)]·4CH_(3)OH(1)and[Gd_(2)(dbm)_(2)(L_(2))_(2)(CH_(3)OH)_(2)]·2CH_(3)OH(2),where H_(3)L_(1)=(Z)-N'-[4-(diethylamino)-2-hydroxybenzylidene...Two Gd_(2)complexes,namely[Gd_(2)(dbm)_(2)(HL_(1))_(2)(CH_(3)OH)_(2)]·4CH_(3)OH(1)and[Gd_(2)(dbm)_(2)(L_(2))_(2)(CH_(3)OH)_(2)]·2CH_(3)OH(2),where H_(3)L_(1)=(Z)-N'-[4-(diethylamino)-2-hydroxybenzylidene]-2-hydroxyacetohydrazide,H_(2)L_(2)=(E)-N'-(5-bromo-2-hydroxy-3-methoxybenzylidene)nicotinohydrazide,Hdbm=dibenzoylmethane,have been constructed by adopting the solvothermal method.Structural characterization unveils that both complexes 1 and 2 are constituted by two Gd^(3+)ions,two dbm-ions,two CH_(3)OH molecules,and two polydentate Schiff-base ligands(HL_(1)^(2-)or L_(2)^(2-)).In addition,complex 1 contains four free methanol molecules,whereas complex 2 harbors two free methanol molecules.By investigating the interactions between complexes 1 and 2 and four types of bacteria(Bacillus subtilis,Escherichia coli,Staphylococcus aureus,Candida albicans),it was found that both complexes 1 and 2 exhibited potent antibacte-rial activities.The interaction mechanisms between the ligands H_(3)L_(1),H_(2)L_(2),complexes 1 and 2,and calf thymus DNA(CT-DNA)were studied using ultraviolet-visible spectroscopy,fluorescence titration,and cyclic voltammetry.The results demonstrated that both complexes 1 and 2 can intercalate into CT-DNA molecules,thereby inhibiting bacterial proliferation to achieve the antibacterial effects.CCDC:2401116,1;2401117,2.展开更多
A novel 3D metal-organic framework(MOF)[Pr_(2)(L)_(3)(H_(2)O)5·H_(2)O]n(Pr-1),(H_(2)L=4,4'-oxybis(benzoic acid))with a rare structure of broken layer net,was constructed under the condition of solvothermal sy...A novel 3D metal-organic framework(MOF)[Pr_(2)(L)_(3)(H_(2)O)5·H_(2)O]n(Pr-1),(H_(2)L=4,4'-oxybis(benzoic acid))with a rare structure of broken layer net,was constructed under the condition of solvothermal synthesis.The struc-ture and crystal net were analyzed and characterized.This rod net of Pr-1 is new to both RCSR and ToposPro data-bases,and is named as rn-12 as suggested.Due to the luminescent properties of H_(2)L and Pr(Ⅲ),the solid-state fluo-rescence property and sensing performance(solvents and metal ions)of Pr-1 were investigated.The sensing experi-ments indicated that Pr-1 could act as a fluorescence sensor to detect Cd^(2+)ions with good sensitivity.In addition,antibacterial activities show that Pr-1 exhibited stronger antibacterial activity against Escherichia coli(E.coli),Staphylococcus aureus(S.aureus),and Bacillus subtilis(B.subtilis)compared to synthetic materials.展开更多
Na-montruorillonite （Na-MMT） was exchanged with three quaternary atkylphosphonium salts： decyl tributylphosphonium bromide （DTBPBr）, dodecyl tributylphosphonium bromide （DDTBPBr） and hexadecyl tributylphosphoni...Na-montruorillonite （Na-MMT） was exchanged with three quaternary atkylphosphonium salts： decyl tributylphosphonium bromide （DTBPBr）, dodecyl tributylphosphonium bromide （DDTBPBr） and hexadecyl tributylphosphonium bromide （HDTBPBr）, to investigate the effects of phosphonium salts species and relative molecular mass on the characteristics, morphology, thermal stability and long-acting antibacterial property of phosphonium montmorillonites. The resulting modified montmorillonites were characterized by the FTIR, XRD, TEM, and TG/DTG techniques. And minimum inhibitory concentration （MIC） was used to investigate antibacterial activity. The results show that the phosphonium salts are intercalated into Na-MMT, and the basal spacing of P-MMTs is enlarged with the increase of phosphonium salt content or the growth of alkyl chain length. DDTBP-MMT-3 with 19.83% （mass fraction of dodecyl tributylphosphonium salts, displays excellent thermal stability and long-acting antibacterial activity.展开更多
The purpose of this study is to isolate the active fraction from the crude extract of Prinsepia utilis Royle and to determine its antibacterial activity against the standard and drug-resistant bacteria strains in vitr...The purpose of this study is to isolate the active fraction from the crude extract of Prinsepia utilis Royle and to determine its antibacterial activity against the standard and drug-resistant bacteria strains in vitro. The Prinsepia utilis Royle was extracted in three portions by using petroleum ether, ethanol and water by the continuation recirculate extraction. The antibacterial activity of the extracts were evaluated by the determination of Minimum Inhibitory Concentration （MIC） and Minimum Bactericidal Concentration （MBC） values. The results showed that the ethanol extract and aqueous extract of petroleum ether showed the weakest inhibition. MIC values of the aqueous Prinsepia utilis Royle were found that they had significant effects against bacteria, while ethanol extracts against three standard bacteria （S. aureus ATCC25923, E. coli 44102, Salmonella 50041） were 25, 25, 50 mg·mL^-1 and 50, 100, 100 mg·mL^-1, MIC values of three drug-resistant bacteria （S. aureus GL17, E. coli EYAC08-56, Salmonella STQD2G.） were 50, 50, 50 mg·mL^-1 and 100, 100, 200 mg·mL^-1, respectively. MBC values of two extracts against three standard strains were 25, 50, 100mg·mL^-1 and 50, 100, 200 mg·mL^-1, MBC values of three drug-resistant bacteria were 100, 100, 100mg·mL^-1 and 200, 200, 200 mg·mL^-1, respectively.展开更多
The aim of this study to focused on bioinspired synthesis of silver nanoparticles(AgNPs)as a viable alternative to eradicate the existing physicochemical processes.In this context,the bioinspired AgNPs were synthesize...The aim of this study to focused on bioinspired synthesis of silver nanoparticles(AgNPs)as a viable alternative to eradicate the existing physicochemical processes.In this context,the bioinspired AgNPs were synthesized using leaf extract of M.indica.Optimization of the experimental conditions for the rapid and high yield of AgNPs in minimum investment of time and expense have been carried out along with their antibacterial efficacy evaluated.For this reason,the variation of parameters like the concentration of the silver precursors,reducing agent,time,pH,and temperature of synthesis were realized.Synthesized AgNPs were characterized by UV-Visible spectroscopy,X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FTIR)and transmission electron microscopy(TEM)techniques.UV-Visible spectra gave surface plasmon resonance(SPR)at 440 nm for AgNPs.Fourier transform infrared spectroscopy(FTIR)and X-ray diffraction(XRD)techniques were further confirmed the synthesis and crystalline nature of AgNPs respectively.Transmission electron microscopy(TEM)observed spherical shapes of synthesized AgNPs within range 5～20 nm.The results of the current study indicate that optimization process play apivotal role in the AgNPs synthesis and biogenic synthesized AgNPs might be used against bacterial pathogens.展开更多
Onion(Allium cepa L.)is a common biennial herb,and contains allicin compounds which can kill harmful microorganism.The antibacterial effects of raw and mature onion juice of purple,yellow and white-skinned onions at d...Onion(Allium cepa L.)is a common biennial herb,and contains allicin compounds which can kill harmful microorganism.The antibacterial effects of raw and mature onion juice of purple,yellow and white-skinned onions at different concentrations on Escherichia coli(E.coli)and Staphylococcus aureus(S.aureus)were studied.There were differences among the antibacterial effects of raw and mature onion juice of purple,yellow and white-skinned onions at different concentrations.What was more,the antibacterial effects of raw onion juice were better than those of the mature one.The antibacterial effects of high concentration onion juice were better than those of the low one.The content of the total flavonoids in raw purple onion was higher than that in mature onion,and reached extremely significant levels in 50%,75%and 100%,respectively.Through comparison,it was found that onion juice of purple-skinned had the best suppression effects on S.aureus(gram-positive bacterium)and E.coli(gram-negative bacterium),and gram-positive bacterium had better suppression effects than gram-negative bacterium.It wound provide the basis about bioactive function and antibacterial drugs.展开更多
The combination of solar disinfection and photocatalysis technology presents a viable solution for eliminating harmful pathogenic microorganisms from water.However,some photocatalysts(e.g.,zinc oxide-based composites)...The combination of solar disinfection and photocatalysis technology presents a viable solution for eliminating harmful pathogenic microorganisms from water.However,some photocatalysts(e.g.,zinc oxide-based composites)are susceptible to pH-dependent dissolution in water,which can result in the loss of photocatalysts and additional environ-mental pollution.To obtain zinc oxide-based composites with low dissolution and high antibacterial efficiency for pho-tocatalytic water disinfection,we prepared MoS_(2)/ZnO@CS composites via a precipitation method to encapsulate chitosan(CS)around MoS_(2)/ZnO.The amino groups in the CS molecules act as storerooms for hydrogen ions,which inhibits the dissolution of zinc oxide.In addition,the MoS_(2)/ZnO@CS composites exhibit high production of reactive oxygen species(ROS)and broad-spectrum antibacterial activity under simulated solar irradiation(0.1 W·cm^(-2)).This makes it an excellent antibacterial agent for solar disinfection in water treatment.展开更多
Nanocomposites of zinc/bentonite clay were synthesized for use as an antibacterial material by a quick and simple alkaline ion exchange method. The synthesis of zinc doped bentonite nanocomposite was accomplished by p...Nanocomposites of zinc/bentonite clay were synthesized for use as an antibacterial material by a quick and simple alkaline ion exchange method. The synthesis of zinc doped bentonite nanocomposite was accomplished by placing bentonite in a melting bath of ZnSO4 for 10, 20, 40, 60 and 90 rain. The complexes were characterized by XRD, SEM and DRS. XRD analyses and SEM observations confirmed the diffusion of zinc to the clay surfaces. Antibacterial activity tests against Escherichia coli showed that bentonite did not present any antibacterial properties, but after alkaline ion exchange treatment, inhibition was noted. The highest antibacterial activity was observed with ZnO/bentonite composite alkaline ion exchange for 60 and 90 rain. Interestingly, the leaching test indicated that ZnO/bentonite did not present any risk for drinking water treatment.展开更多
In this study, we investigated the performance improvement caused by the addition of copper(Cu)nanoparticles to high-density polyethylene(HDPE) matrix material. Composite materials, with filler percentages of 0.0, 2.0...In this study, we investigated the performance improvement caused by the addition of copper(Cu)nanoparticles to high-density polyethylene(HDPE) matrix material. Composite materials, with filler percentages of 0.0, 2.0, 4.0, 6.0, 8.0, and 10.0 wt% were synthesized through the material extrusion(MEX)3D printing technique. The synthesized nanocomposite filaments were utilized for the manufacturing of specimens suitable for the experimental procedure that followed. Hence, we were able to systematically investigate their tensile, flexural, impact, and microhardness properties through various mechanical tests that were conducted according to the corresponding standards. Broadband Dielectric Spectroscopy was used to investigate the electrical/dielectric properties of the composites. Moreover, by employing means of Raman spectroscopy and thermogravimetric analysis(TGA) we were also able to further investigate their vibrational, structural, and thermal properties. Concomitantly, means of scanning electron microscopy(SEM), as well as atomic force microscopy(AFM), were used for the examination of the morphological and structural characteristics of the synthesized specimens, while energy-dispersive Xray spectroscopy(EDS) was also performed in order to receive a more detailed picture on the structural characteristics of the various synthesized composites. The corresponding nanomaterials were also assessed for their antibacterial properties regarding Staphylococcus aureus(S. aureus) and Escherichia coli(E. coli) with the assistance of a method named screening agar well diffusion. The results showed that the mechanical properties of HDPE benefited from the utilization of Cu as a filler, as they showed a notable improvement. The specimen of HDPE/Cu 4.0 wt% was the one that presented the highest levels of reinforcement in four out of the seven tested mechanical properties(for example, it exhibited a 36.7%improvement in the flexural strength, compared to the pure matrix). At the same time, the nanocomposites were efficient against the S. aureus bacterium and less efficient against the E. coli bacterium.The use of such multi-functional, robust nanocomposites in MEX 3D printing is positively impacting applications in various fields, most notably in the defense and security sectors. The latter becomes increasingly important if one takes into account that most firearms encompass various polymeric parts that require robustness and improved mechanical properties, while at the same time keeping the risk of spreading various infectious microorganisms at a bare minimum.展开更多
To investigate the antibacterial activity of commercial organic acid Activate WD （WD）, the minimal inhibitory concentration （MIC） and minimal bactericidal concentration （MBC） of WD against Staphylococcus aureus,...To investigate the antibacterial activity of commercial organic acid Activate WD （WD）, the minimal inhibitory concentration （MIC） and minimal bactericidal concentration （MBC） of WD against Staphylococcus aureus, Escherichia coli, Salmonella pullorum, and Campylobacter jejuni were determined by double broth dilution method. Bacteria were added in a mixture of water and commercial broiler feed adjusted by WD into pH 3.0, 4.0, and 5.0; the survival of bacteria was determined by a direct plate count method at 0, 0.5, 1, 4, 8, and 24 h after being mixed to test the bactericidal potential of WD. The results showed that the MIC of WD against four bacteria was 0.3125%, and the MBC was 0.625%. At pH 3.0, bacteria could not survive. Campylobacter jejuni died after 4 h of incubation at pH 4.0, 5.0, whereas for other three bacteria, the bacterium numbers were below detection limits until 8 h of incubation. In conclusion, WD had significant antibacterial activity, and could be used on farms to prevent cross-infection via rearing water.展开更多
文摘Two Gd_(2)complexes,namely[Gd_(2)(dbm)_(2)(HL_(1))_(2)(CH_(3)OH)_(2)]·4CH_(3)OH(1)and[Gd_(2)(dbm)_(2)(L_(2))_(2)(CH_(3)OH)_(2)]·2CH_(3)OH(2),where H_(3)L_(1)=(Z)-N'-[4-(diethylamino)-2-hydroxybenzylidene]-2-hydroxyacetohydrazide,H_(2)L_(2)=(E)-N'-(5-bromo-2-hydroxy-3-methoxybenzylidene)nicotinohydrazide,Hdbm=dibenzoylmethane,have been constructed by adopting the solvothermal method.Structural characterization unveils that both complexes 1 and 2 are constituted by two Gd^(3+)ions,two dbm-ions,two CH_(3)OH molecules,and two polydentate Schiff-base ligands(HL_(1)^(2-)or L_(2)^(2-)).In addition,complex 1 contains four free methanol molecules,whereas complex 2 harbors two free methanol molecules.By investigating the interactions between complexes 1 and 2 and four types of bacteria(Bacillus subtilis,Escherichia coli,Staphylococcus aureus,Candida albicans),it was found that both complexes 1 and 2 exhibited potent antibacte-rial activities.The interaction mechanisms between the ligands H_(3)L_(1),H_(2)L_(2),complexes 1 and 2,and calf thymus DNA(CT-DNA)were studied using ultraviolet-visible spectroscopy,fluorescence titration,and cyclic voltammetry.The results demonstrated that both complexes 1 and 2 can intercalate into CT-DNA molecules,thereby inhibiting bacterial proliferation to achieve the antibacterial effects.CCDC:2401116,1;2401117,2.
文摘A novel 3D metal-organic framework(MOF)[Pr_(2)(L)_(3)(H_(2)O)5·H_(2)O]n(Pr-1),(H_(2)L=4,4'-oxybis(benzoic acid))with a rare structure of broken layer net,was constructed under the condition of solvothermal synthesis.The struc-ture and crystal net were analyzed and characterized.This rod net of Pr-1 is new to both RCSR and ToposPro data-bases,and is named as rn-12 as suggested.Due to the luminescent properties of H_(2)L and Pr(Ⅲ),the solid-state fluo-rescence property and sensing performance(solvents and metal ions)of Pr-1 were investigated.The sensing experi-ments indicated that Pr-1 could act as a fluorescence sensor to detect Cd^(2+)ions with good sensitivity.In addition,antibacterial activities show that Pr-1 exhibited stronger antibacterial activity against Escherichia coli(E.coli),Staphylococcus aureus(S.aureus),and Bacillus subtilis(B.subtilis)compared to synthetic materials.
基金Projects(20676049, 20871058) supported by the National Natural Science Foundation of China Project(05200555) supported by the Natural Science Foundation of Guangdong Province, China Projects(2007B090400105, 2008A010500005) supported by the Foundation of Enterprise-University-Research Institute Cooperation from Guangdong Province and Ministry of Education of China
文摘Na-montruorillonite （Na-MMT） was exchanged with three quaternary atkylphosphonium salts： decyl tributylphosphonium bromide （DTBPBr）, dodecyl tributylphosphonium bromide （DDTBPBr） and hexadecyl tributylphosphonium bromide （HDTBPBr）, to investigate the effects of phosphonium salts species and relative molecular mass on the characteristics, morphology, thermal stability and long-acting antibacterial property of phosphonium montmorillonites. The resulting modified montmorillonites were characterized by the FTIR, XRD, TEM, and TG/DTG techniques. And minimum inhibitory concentration （MIC） was used to investigate antibacterial activity. The results show that the phosphonium salts are intercalated into Na-MMT, and the basal spacing of P-MMTs is enlarged with the increase of phosphonium salt content or the growth of alkyl chain length. DDTBP-MMT-3 with 19.83% （mass fraction of dodecyl tributylphosphonium salts, displays excellent thermal stability and long-acting antibacterial activity.
基金Supported by Program for Changjiang Scholars and Innovative Research Team in University (PCSIRT0848)
文摘The purpose of this study is to isolate the active fraction from the crude extract of Prinsepia utilis Royle and to determine its antibacterial activity against the standard and drug-resistant bacteria strains in vitro. The Prinsepia utilis Royle was extracted in three portions by using petroleum ether, ethanol and water by the continuation recirculate extraction. The antibacterial activity of the extracts were evaluated by the determination of Minimum Inhibitory Concentration （MIC） and Minimum Bactericidal Concentration （MBC） values. The results showed that the ethanol extract and aqueous extract of petroleum ether showed the weakest inhibition. MIC values of the aqueous Prinsepia utilis Royle were found that they had significant effects against bacteria, while ethanol extracts against three standard bacteria （S. aureus ATCC25923, E. coli 44102, Salmonella 50041） were 25, 25, 50 mg·mL^-1 and 50, 100, 100 mg·mL^-1, MIC values of three drug-resistant bacteria （S. aureus GL17, E. coli EYAC08-56, Salmonella STQD2G.） were 50, 50, 50 mg·mL^-1 and 100, 100, 200 mg·mL^-1, respectively. MBC values of two extracts against three standard strains were 25, 50, 100mg·mL^-1 and 50, 100, 200 mg·mL^-1, MBC values of three drug-resistant bacteria were 100, 100, 100mg·mL^-1 and 200, 200, 200 mg·mL^-1, respectively.
文摘The aim of this study to focused on bioinspired synthesis of silver nanoparticles(AgNPs)as a viable alternative to eradicate the existing physicochemical processes.In this context,the bioinspired AgNPs were synthesized using leaf extract of M.indica.Optimization of the experimental conditions for the rapid and high yield of AgNPs in minimum investment of time and expense have been carried out along with their antibacterial efficacy evaluated.For this reason,the variation of parameters like the concentration of the silver precursors,reducing agent,time,pH,and temperature of synthesis were realized.Synthesized AgNPs were characterized by UV-Visible spectroscopy,X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FTIR)and transmission electron microscopy(TEM)techniques.UV-Visible spectra gave surface plasmon resonance(SPR)at 440 nm for AgNPs.Fourier transform infrared spectroscopy(FTIR)and X-ray diffraction(XRD)techniques were further confirmed the synthesis and crystalline nature of AgNPs respectively.Transmission electron microscopy(TEM)observed spherical shapes of synthesized AgNPs within range 5～20 nm.The results of the current study indicate that optimization process play apivotal role in the AgNPs synthesis and biogenic synthesized AgNPs might be used against bacterial pathogens.
基金Supported by the Scientific Research Projects of Basic Scientific Research Business Expenses of Undergraduate Universities in Heilongjiang Province(135309363)Fundamental Research Business Expenses of Heilongjiang Provincial Universities(Specialized Subjects of Plant Food Processing Technology)(YSTSXK201889)+2 种基金Heilongjiang General Undergraduate Universities Young Innovative Talents Training Plan(UNPYSCT-2018101)Natural Science Foundation of Heilongjiang Province(LH2019C067)Science and Technology Plan Project of Qiqihar City(NYGG-201915)。
文摘Onion(Allium cepa L.)is a common biennial herb,and contains allicin compounds which can kill harmful microorganism.The antibacterial effects of raw and mature onion juice of purple,yellow and white-skinned onions at different concentrations on Escherichia coli(E.coli)and Staphylococcus aureus(S.aureus)were studied.There were differences among the antibacterial effects of raw and mature onion juice of purple,yellow and white-skinned onions at different concentrations.What was more,the antibacterial effects of raw onion juice were better than those of the mature one.The antibacterial effects of high concentration onion juice were better than those of the low one.The content of the total flavonoids in raw purple onion was higher than that in mature onion,and reached extremely significant levels in 50%,75%and 100%,respectively.Through comparison,it was found that onion juice of purple-skinned had the best suppression effects on S.aureus(gram-positive bacterium)and E.coli(gram-negative bacterium),and gram-positive bacterium had better suppression effects than gram-negative bacterium.It wound provide the basis about bioactive function and antibacterial drugs.
基金supported in part by the National Natural Science Foundation of China(12174366)Fundamental Re-search Funds for the Central Universities(WK3450000005)the Anhui Provincial Natural Science Foundation(2108085MC93).
文摘The combination of solar disinfection and photocatalysis technology presents a viable solution for eliminating harmful pathogenic microorganisms from water.However,some photocatalysts(e.g.,zinc oxide-based composites)are susceptible to pH-dependent dissolution in water,which can result in the loss of photocatalysts and additional environ-mental pollution.To obtain zinc oxide-based composites with low dissolution and high antibacterial efficiency for pho-tocatalytic water disinfection,we prepared MoS_(2)/ZnO@CS composites via a precipitation method to encapsulate chitosan(CS)around MoS_(2)/ZnO.The amino groups in the CS molecules act as storerooms for hydrogen ions,which inhibits the dissolution of zinc oxide.In addition,the MoS_(2)/ZnO@CS composites exhibit high production of reactive oxygen species(ROS)and broad-spectrum antibacterial activity under simulated solar irradiation(0.1 W·cm^(-2)).This makes it an excellent antibacterial agent for solar disinfection in water treatment.
文摘Nanocomposites of zinc/bentonite clay were synthesized for use as an antibacterial material by a quick and simple alkaline ion exchange method. The synthesis of zinc doped bentonite nanocomposite was accomplished by placing bentonite in a melting bath of ZnSO4 for 10, 20, 40, 60 and 90 rain. The complexes were characterized by XRD, SEM and DRS. XRD analyses and SEM observations confirmed the diffusion of zinc to the clay surfaces. Antibacterial activity tests against Escherichia coli showed that bentonite did not present any antibacterial properties, but after alkaline ion exchange treatment, inhibition was noted. The highest antibacterial activity was observed with ZnO/bentonite composite alkaline ion exchange for 60 and 90 rain. Interestingly, the leaching test indicated that ZnO/bentonite did not present any risk for drinking water treatment.
文摘In this study, we investigated the performance improvement caused by the addition of copper(Cu)nanoparticles to high-density polyethylene(HDPE) matrix material. Composite materials, with filler percentages of 0.0, 2.0, 4.0, 6.0, 8.0, and 10.0 wt% were synthesized through the material extrusion(MEX)3D printing technique. The synthesized nanocomposite filaments were utilized for the manufacturing of specimens suitable for the experimental procedure that followed. Hence, we were able to systematically investigate their tensile, flexural, impact, and microhardness properties through various mechanical tests that were conducted according to the corresponding standards. Broadband Dielectric Spectroscopy was used to investigate the electrical/dielectric properties of the composites. Moreover, by employing means of Raman spectroscopy and thermogravimetric analysis(TGA) we were also able to further investigate their vibrational, structural, and thermal properties. Concomitantly, means of scanning electron microscopy(SEM), as well as atomic force microscopy(AFM), were used for the examination of the morphological and structural characteristics of the synthesized specimens, while energy-dispersive Xray spectroscopy(EDS) was also performed in order to receive a more detailed picture on the structural characteristics of the various synthesized composites. The corresponding nanomaterials were also assessed for their antibacterial properties regarding Staphylococcus aureus(S. aureus) and Escherichia coli(E. coli) with the assistance of a method named screening agar well diffusion. The results showed that the mechanical properties of HDPE benefited from the utilization of Cu as a filler, as they showed a notable improvement. The specimen of HDPE/Cu 4.0 wt% was the one that presented the highest levels of reinforcement in four out of the seven tested mechanical properties(for example, it exhibited a 36.7%improvement in the flexural strength, compared to the pure matrix). At the same time, the nanocomposites were efficient against the S. aureus bacterium and less efficient against the E. coli bacterium.The use of such multi-functional, robust nanocomposites in MEX 3D printing is positively impacting applications in various fields, most notably in the defense and security sectors. The latter becomes increasingly important if one takes into account that most firearms encompass various polymeric parts that require robustness and improved mechanical properties, while at the same time keeping the risk of spreading various infectious microorganisms at a bare minimum.
文摘To investigate the antibacterial activity of commercial organic acid Activate WD （WD）, the minimal inhibitory concentration （MIC） and minimal bactericidal concentration （MBC） of WD against Staphylococcus aureus, Escherichia coli, Salmonella pullorum, and Campylobacter jejuni were determined by double broth dilution method. Bacteria were added in a mixture of water and commercial broiler feed adjusted by WD into pH 3.0, 4.0, and 5.0; the survival of bacteria was determined by a direct plate count method at 0, 0.5, 1, 4, 8, and 24 h after being mixed to test the bactericidal potential of WD. The results showed that the MIC of WD against four bacteria was 0.3125%, and the MBC was 0.625%. At pH 3.0, bacteria could not survive. Campylobacter jejuni died after 4 h of incubation at pH 4.0, 5.0, whereas for other three bacteria, the bacterium numbers were below detection limits until 8 h of incubation. In conclusion, WD had significant antibacterial activity, and could be used on farms to prevent cross-infection via rearing water.
