A new technique for generating heavy metal fumes with high melting point.
There are many kinds of fumes containing heavy metals in the working area. They sometimes have bad effects on the living body. It is important to determine their particle size distribution for considering the effects of those metals on health, together with measuring their amounts. For this purpose, it is neces-sary to generate fumes which are suitable to use. However, effective methods for generating fumes of heavy metals with high melting points have not been developed.In this study we attempted to determine whether the plasma flame metal sprayer can be used as a fume generator. The size distribution, particle form and amounts of the generated fumes were determined for the iron fume which were generated with this instrument under the various conditions. The fume was to consist of coagulated fine particles and dispersed globular particles. Our attempt extended to the generation of fumes consisting not only of one kind of metal but also of two kinds of metal. It was also found that fumes having the required radio might be generated by controlling the ratio of the metals in the powder mixture.We conclude that this instrument might be suitable for generating fumes of heavy metals in the laboratory.
Development an Ultrasonic of a New Aerosol Nebulizer Generating Cell with
A new efficient cell was developed to generate a large quantity of aerosol using an ultrasonic nebulizer. The currently used conventional pail-type cell cannot generate such a large quantity of aerosol because a large portion of the mist is lost by agglomeration and subsequent liquefaction onto the cell wall and liquid surface. The newly developed cell is a chimney-type cell characterized by the attachment of a vertical cylinder at its center and a partition to separate the cell into upper and lower compartments, each of which is supplied with a carrier air flow. The mist emanating from the fluid surface is carried upward through the vertical cylinder by a laminar primary airflow. The secondary airflow served to sheath the primary airflow containing the mist and to prevent the impact and adhesion of the mist on the surrounding wall. The nebulizing rate of Ti02 suspension was found to be three times higher with the chimney-type than with the pail-type. No differences were found between the two types in terms of particle diameters, particle size distribution, and the electron microscopic images of the aerosol. It was concluded that a commercially available ultrasonic nebulizer equipped with the chimney-type cell allowed generation of a large quantity of aerosol for use in inhalation animal experiments.
In vitro metastatic colonization of human ovarian cancer cells to the omentum
Despite the potentially crucial contributions of the omentum in the regulation of ovarian cancer metastatic growth, it remains a poorly understood organ. Due to its anatomic location and structural fragility, the omentum presents inherent challenges to mechanism-based in vivo studies. Thus, the availability of an ex vivo omental model would, in part, address some of these difficulties posed. Here we describe a technique for identifying, isolating and maintaining ex vivo cultures of omenta from immune-compromised and -competent mice. Ex vivo culture conditions were developed that maintain tissue viability, architecture, and function for up to 10 days. Further experiments demonstrate that the ex vivo culture conditions allow for the proliferation of ovarian cancer cells in vitro and support a similar pattern of microscopic lesions after either intraperitoneal injection of ovarian cancer cells or co-culture of ovarian cancer cells with the omentum. In agreement with previous studies from our laboratory, histologic evaluation of these specimens found that ovarian cancer cells, as well as other peritoneal cancer cells, preferentially accumulate in, and colonize, omental areas rich in immune cells. We now recognize that these are specific, functional structures referred to as milky spots. In sum, these are foundational studies of a readily accessible model, which is easily manipulated and can be immediately used to study the dynamic process of omental colonization. It is hoped that investigators will use the data herein as a starting point for refinements and modifications which will enable them to tailor the model to the specific needs of the experimental question(s) they wish to pursue.