Hardness, friction and wear characteristics of electrodeposited RE Ni W P B 4C PTFE composite coatings were studied, and the reason for these fine characteristics was explained in respect of structure. The results sho...Hardness, friction and wear characteristics of electrodeposited RE Ni W P B 4C PTFE composite coatings were studied, and the reason for these fine characteristics was explained in respect of structure. The results show that 1) the structure of RE Ni W P B 4C PTFE composite coatings experiences a transformation process from amorphous to mixture then to crystal as the heat treatment temperature rises; 2) incorporating of B 4C greatly increases the hardness of the coating; 3) the wear resistance of the coating is best with heat treatment for 1?h at 300?℃, which is greatly superior to that of the other traditional coatings.展开更多
The research question being studied in this paper is how do different types of bacteria as food (Pseudomonas fluorescens and Bacillus megaterium) affect the lifespan of Caenorhabditis elegans in dpy-11 mutant-type and...The research question being studied in this paper is how do different types of bacteria as food (Pseudomonas fluorescens and Bacillus megaterium) affect the lifespan of Caenorhabditis elegans in dpy-11 mutant-type and wild-type? P. fluorescens and B. megaterium will be the two pathogens that will be tested on two different types of C. elegans: mutant-type dpy-11 and wild-type. From the analysis of primary articles studying these pathogens, it can be concluded that P. fluorescens and B. megaterium are decent contenders for allowing C. elegans to grow and possibly extend the lifespan of it. P. fluorescens will allow the lifespan of the two types of nematodes to be longer. Additionally, the mu-tant-type dpy-11 of C. elegans will have a much longer lifespan, even double, compared to that of the wild-type. The results showed P. fluorescens had a longer lifespan than B. megaterium but not as long as C. elegans’ main food source, E. coli. C. elegans mutant dpy-11 had a longer lifespan than the wild-type. Furthermore, there were no C. elegans present in the B. megaterium wild-type plates.展开更多
Objective To study the modulatory effect of distillate of Ocimum sanctum （traditionally known as Tulsi） leaf extract （DTLE） on genotoxicants. Methods In the present investigation, we studied the antigenotoxic and ...Objective To study the modulatory effect of distillate of Ocimum sanctum （traditionally known as Tulsi） leaf extract （DTLE） on genotoxicants. Methods In the present investigation, we studied the antigenotoxic and anticlastogenic effect of distillate of Tulsi leaf extract on （i） human polymorphonuclear leukocytes by evaluating the DNA strand break without metabolic activation against mitomycin C （MMC） and hexavalent chromium （Cr^＋6） and （ii） human peripheral lymphocytes （in vitro） with or without metabolic activation against mitomycin C （MMC）, hexavalent chromium （Cr^＋6） and B[a]P by evaluating chromosomal aberration （CA） and micronucleus assay （MN）. Three different doses of DTLE, 50 μL/mL, 100 μL/mL, and 200 μL/mL were selected on the basis of cytotoxicity assay and used for studying DNA strand break, chromosomal aberration and micronucleus emergence. The following positive controls were used for inducing genotoxicity and clastogenicity MMC （0.29 μmol/L） for DNA strand break, chromosomal aberration and 0.51 μmol/L for micronucleus assay; Potassium dichromate （Cr^＋6） 600 μmol/L for DNA strand break and 5 μmol/L for chromosomal aberration and micronucleus assay; Benzo[a]pyrene （30 μmol/L） for chromosomal aberration and 40 μmol/L for micronucleus assay. The active ingredients present in the distillate of Tulsi leaf extract were identified by HPLC and LC-MS. Results Mitomycin C （MMC） and hexavalent chromium （Cr^＋6） induced statistically significant DNA strand break of respectively 69% and 71% （P〈0.001） as revealed by fluorometric analysis of DNA unwinding. Furthermore, the damage could be protected with DTLE （50 μL/mL, 100 μL/mL, and 200 μL/mL） on simultaneous treatment. Chromosomal aberration and micronucleus formation induced by MMC, Cr^＋6 and B[a]P were significantly protected （P〈0.001） by DTLE with and without metabolic activation. Conclusion Distillate of Tulsi leaf extract possesses antioxidants contributed mainly by eugenol, luteolin and apigenin as identified by LC-MS. These active ingredients may have the protective effect against genotoxicants.展开更多
文摘Hardness, friction and wear characteristics of electrodeposited RE Ni W P B 4C PTFE composite coatings were studied, and the reason for these fine characteristics was explained in respect of structure. The results show that 1) the structure of RE Ni W P B 4C PTFE composite coatings experiences a transformation process from amorphous to mixture then to crystal as the heat treatment temperature rises; 2) incorporating of B 4C greatly increases the hardness of the coating; 3) the wear resistance of the coating is best with heat treatment for 1?h at 300?℃, which is greatly superior to that of the other traditional coatings.
文摘The research question being studied in this paper is how do different types of bacteria as food (Pseudomonas fluorescens and Bacillus megaterium) affect the lifespan of Caenorhabditis elegans in dpy-11 mutant-type and wild-type? P. fluorescens and B. megaterium will be the two pathogens that will be tested on two different types of C. elegans: mutant-type dpy-11 and wild-type. From the analysis of primary articles studying these pathogens, it can be concluded that P. fluorescens and B. megaterium are decent contenders for allowing C. elegans to grow and possibly extend the lifespan of it. P. fluorescens will allow the lifespan of the two types of nematodes to be longer. Additionally, the mu-tant-type dpy-11 of C. elegans will have a much longer lifespan, even double, compared to that of the wild-type. The results showed P. fluorescens had a longer lifespan than B. megaterium but not as long as C. elegans’ main food source, E. coli. C. elegans mutant dpy-11 had a longer lifespan than the wild-type. Furthermore, there were no C. elegans present in the B. megaterium wild-type plates.
文摘Objective To study the modulatory effect of distillate of Ocimum sanctum （traditionally known as Tulsi） leaf extract （DTLE） on genotoxicants. Methods In the present investigation, we studied the antigenotoxic and anticlastogenic effect of distillate of Tulsi leaf extract on （i） human polymorphonuclear leukocytes by evaluating the DNA strand break without metabolic activation against mitomycin C （MMC） and hexavalent chromium （Cr^＋6） and （ii） human peripheral lymphocytes （in vitro） with or without metabolic activation against mitomycin C （MMC）, hexavalent chromium （Cr^＋6） and B[a]P by evaluating chromosomal aberration （CA） and micronucleus assay （MN）. Three different doses of DTLE, 50 μL/mL, 100 μL/mL, and 200 μL/mL were selected on the basis of cytotoxicity assay and used for studying DNA strand break, chromosomal aberration and micronucleus emergence. The following positive controls were used for inducing genotoxicity and clastogenicity MMC （0.29 μmol/L） for DNA strand break, chromosomal aberration and 0.51 μmol/L for micronucleus assay; Potassium dichromate （Cr^＋6） 600 μmol/L for DNA strand break and 5 μmol/L for chromosomal aberration and micronucleus assay; Benzo[a]pyrene （30 μmol/L） for chromosomal aberration and 40 μmol/L for micronucleus assay. The active ingredients present in the distillate of Tulsi leaf extract were identified by HPLC and LC-MS. Results Mitomycin C （MMC） and hexavalent chromium （Cr^＋6） induced statistically significant DNA strand break of respectively 69% and 71% （P〈0.001） as revealed by fluorometric analysis of DNA unwinding. Furthermore, the damage could be protected with DTLE （50 μL/mL, 100 μL/mL, and 200 μL/mL） on simultaneous treatment. Chromosomal aberration and micronucleus formation induced by MMC, Cr^＋6 and B[a]P were significantly protected （P〈0.001） by DTLE with and without metabolic activation. Conclusion Distillate of Tulsi leaf extract possesses antioxidants contributed mainly by eugenol, luteolin and apigenin as identified by LC-MS. These active ingredients may have the protective effect against genotoxicants.
