8 research outputs found
Evaluation of the Antimicrobial Activity of Silver Nanoparticles on Antibiotic-Resistant Pseudomonas aeruginosa
Background: Antimicrobial resistance is one of the major characteristics of infectious agents. Silver nanoparticles (AgNPs) have been introduced as novel antibacterial agents in accordance with the traditional treatments. Our purpose of this study was to evaluate the antimicrobial activity of AgNPs on the Pseudomonas aeruginosa (P. aeruginosa) that are resistant to antibiotics.
Methods: During a cross-sectional study, we tried to evaluate 20 strains of P. aeruginosa isolated from the urine cultures of patients admitted to the hospital due to urinary tract infections. The AgNPs were commercially purchased. The minimum inhibitory concentration (MIC) of AgNPs in different concentrations was determined by the dilution in wells on bacteria. The antibiotic susceptibility pattern of P. aeruginosa was evaluated by the Kirby-Bauer disk diffusion standard.
Results: Current study indicated that P. aeruginosa were resistant to four types of agents including ampicillin (85%), nitrofurantoin (65%), nalidixic acid (65%), and ciprofloxacin (15%) and result of nanosilver indicated that the most MIC was 100 ppm concentration, and six strains of P. aeruginosa were inhibited by it.
Conclusion: Our study presented a new type of silver nanoparticle and indicated that they can be embedded in bone cement to prevent infections once synthetic conditions are tailored for such applications
Aerosol characterization and pulmonary responses in rats after short-term inhalation of fumes generated during resistance spot welding of galvanized steel
Resistance spot welding is a common process to join metals in the automotive industry. Adhesives are often used as sealers to seams of metals that are joined. Anti-spatter compounds sometimes are sprayed onto metals to be welded to improve the weldability. Spot welding produces complex aerosols composed of metal and volatile compounds (VOCs) which can cause lung disease in workers. Male Sprague-Dawley rats (n = 12/treatment group) were exposed by inhalation to 25 mg/m3 of aerosol for 4 h/day × 8 days during spot welding of galvanized zinc (Zn)-coated steel in the presence or absence of a glue or anti-spatter spray. Controls were exposed to filtered air. Particle size distribution and chemical composition of the generated aerosol were determined. At 1 and 7 days after exposure, bronchoalveolar lavage (BAL) was performed to assess lung toxicity. The generated particles mostly were in the submicron size range with a significant number of nanometer-sized particles formed. The primary metals present in the fumes were Fe (72.5%) and Zn (26.3%). The addition of the anti-spatter spray and glue did affect particle size distribution when spot welding galvanized steel, whereas they had no effect on metal composition. Multiple VOCs (e.g., methyl methacrylate, acetaldehyde, ethanol, acetone, benzene, xylene) were identified when spot welding using either the glue or the anti-spatter spray that were not present when welding alone. Markers of lung injury (BAL lactate dehydrogenase) and inflammation (total BAL cells/neutrophils and cytokines/chemokines) were significantly elevated compared to controls 1 day after exposure to the spot welding fumes. The elevated pulmonary response was transient as lung toxicity mostly returned to control values by 7 days. The VOCs or the concentrations that they were generated during the animal exposures had no measurable effect on the pulmonary responses. Inhalation of galvanized spot welding fumes caused acute lung toxicity most likely due to the short-term exposure of particles that contain Zn. Keywords: Resistance spot welding, Aerosol generation, Inhalation, Zinc, Methyl methacrylat
Aerosol characterization and pulmonary responses in rats after short-term inhalation of fumes generated during resistance spot welding of galvanized steel
Resistance spot welding is a common process to join metals in the automotive industry. Adhesives are often used as sealers to seams of metals that are joined. Anti-spatter compounds sometimes are sprayed onto metals to be welded to improve the weldability. Spot welding produces complex aerosols composed of metal and volatile compounds (VOCs) which can cause lung disease in workers. Male Sprague-Dawley rats (n = 12/treatment group) were exposed by inhalation to 25 mg/m3 of aerosol for 4 h/day × 8 days during spot welding of galvanized zinc (Zn)-coated steel in the presence or absence of a glue or anti-spatter spray. Controls were exposed to filtered air. Particle size distribution and chemical composition of the generated aerosol were determined. At 1 and 7 days after exposure, bronchoalveolar lavage (BAL) was performed to assess lung toxicity. The generated particles mostly were in the submicron size range with a significant number of nanometer-sized particles formed. The primary metals present in the fumes were Fe (72.5%) and Zn (26.3%). The addition of the anti-spatter spray and glue did affect particle size distribution when spot welding galvanized steel, whereas they had no effect on metal composition. Multiple VOCs (e.g., methyl methacrylate, acetaldehyde, ethanol, acetone, benzene, xylene) were identified when spot welding using either the glue or the anti-spatter spray that were not present when welding alone. Markers of lung injury (BAL lactate dehydrogenase) and inflammation (total BAL cells/neutrophils and cytokines/chemokines) were significantly elevated compared to controls 1 day after exposure to the spot welding fumes. The elevated pulmonary response was transient as lung toxicity mostly returned to control values by 7 days. The VOCs or the concentrations that they were generated during the animal exposures had no measurable effect on the pulmonary responses. Inhalation of galvanized spot welding fumes caused acute lung toxicity most likely due to the short-term exposure of particles that contain Zn. Keywords: Resistance spot welding, Aerosol generation, Inhalation, Zinc, Methyl methacrylat
Modifying welding process parameters can reduce the neurotoxic potential of manganese-containing welding fumes
Effects of acute inhalation of aerosols generated during resistance spot welding with mild-steel on pulmonary, vascular and immune responses in rats
<i>In Vivo</i> Toxicity Assessment of Occupational Components of the Carbon Nanotube Life Cycle To Provide Context to Potential Health Effects
Pulmonary
toxicity studies on carbon nanotubes focus primarily
on as-produced materials and rarely are guided by a life cycle perspective
or integration with exposure assessment. Understanding toxicity beyond
the as-produced, or pure native material, is critical, due to modifications
needed to overcome barriers to commercialization of applications.
In the first series of studies, the toxicity of as-produced carbon
nanotubes and their polymer-coated counterparts was evaluated in reference
to exposure assessment, material characterization, and stability of
the polymer coating in biological fluids. The second series of studies
examined the toxicity of aerosols generated from sanding polymer-coated
carbon-nanotube-embedded or neat composites. Postproduction modification
by polymer coating did not enhance pulmonary injury, inflammation,
and pathology or <i>in vitro</i> genotoxicity of as-produced
carbon nanotubes, and for a particular coating, toxicity was significantly
attenuated. The aerosols generated from sanding composites embedded
with polymer-coated carbon nanotubes contained no evidence of free
nanotubes. The percent weight incorporation of polymer-coated carbon
nanotubes, 0.15% or 3% by mass, and composite matrix utilized altered
the particle size distribution and, in certain circumstances, influenced
acute <i>in vivo</i> toxicity. Our study provides perspective
that, while the number of workers and consumers increases along the
life cycle, toxicity and/or potential for exposure to the as-produced
material may greatly diminish
<i>In Vivo</i> Toxicity Assessment of Occupational Components of the Carbon Nanotube Life Cycle To Provide Context to Potential Health Effects
Pulmonary
toxicity studies on carbon nanotubes focus primarily
on as-produced materials and rarely are guided by a life cycle perspective
or integration with exposure assessment. Understanding toxicity beyond
the as-produced, or pure native material, is critical, due to modifications
needed to overcome barriers to commercialization of applications.
In the first series of studies, the toxicity of as-produced carbon
nanotubes and their polymer-coated counterparts was evaluated in reference
to exposure assessment, material characterization, and stability of
the polymer coating in biological fluids. The second series of studies
examined the toxicity of aerosols generated from sanding polymer-coated
carbon-nanotube-embedded or neat composites. Postproduction modification
by polymer coating did not enhance pulmonary injury, inflammation,
and pathology or <i>in vitro</i> genotoxicity of as-produced
carbon nanotubes, and for a particular coating, toxicity was significantly
attenuated. The aerosols generated from sanding composites embedded
with polymer-coated carbon nanotubes contained no evidence of free
nanotubes. The percent weight incorporation of polymer-coated carbon
nanotubes, 0.15% or 3% by mass, and composite matrix utilized altered
the particle size distribution and, in certain circumstances, influenced
acute <i>in vivo</i> toxicity. Our study provides perspective
that, while the number of workers and consumers increases along the
life cycle, toxicity and/or potential for exposure to the as-produced
material may greatly diminish