Evaluating the process of borosilicate glass capillaries used for fabrication of in-vitro fertilization (IVF) micro-pipettes

In this paper we investigate a number of gas flames for fire polishing borosilicate glass capillaries used in the manufacturing of IVF micro-pipettes. Hydrofluoric acid (HF) was also used as an alternative to finish the pipette end. Glass micro tools in the IVF industry are drawn from hollow glass capillaries of diameter 1 mm. These capillaries are cut manually to a length of 100 mm from hollow glass rods resulting in sharp and chipped edges. These capillaries are held in a customised holder having padding of soft silicone or rubber. Sharp and uneven edges of these capillaries pick up particles of rubber or soft silicone shavings, rendering them ineffective for IVF treatments. The working range of borosilicate glass is 800-1,200 degrees C. The experiments involved analysis of fire polishing process for borosilicate glass capillaries using candle, butane, propane, 2350 butane propane, oxyacetylene gas flames, finding the optimum distance of the capillary relative to the flame, optimum time for which the capillary should be held in the flame and optimum region of the flame which gives the required temperature range. The results show that 2350 butane propane gas mix is optimum for fire polishing of borosilicate glass capillaries. The paper is concluded by comparing the results of fire polishing with the results of acid polishing, in which HF of 1.6% concentration is used to etch the ends of the borosilicate glass pipettes.

Use Of Micro-Stereology And Quantitative Cyto-Chemistry To Determine The Effects Of Crude Oil-Derived Aromatic-Hydrocarbons On Lysosomal Structure And Function In A Marine Bivalve Mollusk Mytilus-Edulis

The marine bivalve mollusc,Mytilus edulis (blue mussel), is a noted accumulator of many environmental pollutants and is increasingly used for the chemical and biological assessment of environmental impact. The toxic effects of crude oil-derived aromatic hydrocarbons (30 μg/l total hydrocarbons) on the lysosomal-vacuolar system of the digestive cells have been investigated in cryostat sections of hexane-frozen digestive glands. Exposure to aromatic hydrocarbons reduced the cytochemically determined latency of lysosomal β-N-acetylhexosaminidase; lysosomal volume density and surface density increased while the numerical density decreased. Experimental exposure resulted in the formation of very large lysosomes which are believed to be largely autophagic in function and these results indicate a significant structural and functional disturbance of digestive cell lysosomes in response to hydrocarbons.