نتایج جستجو برای: airborne particles
تعداد نتایج: 176432 فیلتر نتایج به سال:
Investigation of the effectiveness of surface treatments that promote a strong bond strength of resin cements to metals can contribute significantly to the longevity of metal-ceramic restorations. This study evaluated the effect of surface treatments on the shear bond strength (SBS) of a resin cement to commercially pure titanium (CP Ti). Ninety cast CP Ti discs were divided into 3 groups (n=30...
The prevalence and severity of asthma has increased in the last 20 years, and the greatest increase has been seen among children and young adults living in U.S. inner cities. The reasons for this increase are obviously complex, but include environmental exposures to allergens and pollutants, changing patterns of medication, and the psychosocial stresses of living in poor inner-city neighborhood...
By the use of a modified ionizer device we describe effective prevention of airborne transmitted influenza A (strain Panama 99) virus infection between animals and inactivation of virus (>97%). Active ionizer prevented 100% (4/4) of guinea pigs from infection. Moreover, the device effectively captured airborne transmitted calicivirus, rotavirus and influenza virus, with recovery rates up to 21%...
BACKGROUND Prevention of postsurgical infection is preferable to treatment. Prevention requires identification and control of the potential sources of microbial contamination. This study investigated whether the density of airborne particulates can predict the density of viable airborne bacteria at the surgery site. METHODS A standard particle analyzer was used to measure the number and diame...
Exposure to specific airborne bacteria indoors is linked to infectious and noninfectious adverse health outcomes. However, the sources and origins of bacteria suspended in indoor air are not well understood. This study presents evidence for elevated concentrations of indoor airborne bacteria due to human occupancy, and investigates the sources of these bacteria. Samples were collected in a univ...
Most studies on the transmission of infectious airborne disease have focused on patient room air changes per hour (ACH) and how ACH provides pathogen dilution and removal. The logical but mostly unproven premise is that greater air change rates reduce the concentration of infectious particles and thus, the probability of airborne disease transmission. Recently, a growing body of research sugges...
Electrostatic space chargers were used to impart a negative charge to airborne dust particles and thereby cause them to be attracted to grounded surfaces. To determine whether negative air ionization could affect the airborne transmission of Salmonella enteritidis, chicks were housed in four controlled-environment isolation cabinets in which airflow was directed across an unoccupied central are...
Objectives: Concentrations of microbial cell wall components such as endotoxin and -D-glucan in airborne submicrometer particle size fraction (PM1, defined as particles with median aerodynamic diameter, da 1 m) have not been well characterized. In this study, airborne concentrations of endotoxin and -D-glucan among different size fractions were quantified in two distinctly different environment...
The broadband albedo values retrieved from satellite sensors are usually compared directly to ground measurements. Some authors have noted the necessity of high spatial resolution albedo estimates to fill the gap between ground measurements and satellite retrievals. In this respect, hyperspectral airborne data with high spatial resolution is a powerful tool. Here, a new operational method for t...
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