Cyclopentene is known to undergo equilibrium polymerization through a metathesis reaction which its bulk and solution polymerizations have been thoroughly investigated. However, we have found that under specific experimental conditions, this monomer polymerizes in the gas phase. The gas phase polymerization is defined here as the conversion of pure gaseous monomer into polymer in the condensed phase. Pure gaseous cyclopentene is found to polymerize on a glass surface in the upper part of the ampoule above the liquid phase when the polymerization is initiated with only tungsten hexachloride. Polymerizations are carried out under high vacuum and in the 10-60oC TEMPERATURE range. In presence of methanol, the colourless formed polymer shrinks slightly, then it can be removed easily from the glass surface and simply dried under vacuum without any other purification process. From kinetic measurements, an overall activation energy of 63.47 kJ/mol is obtained for the conversion of one mole of gaseous monomer to one unit of condensed polymer. GPC Chromatograms of polymer samples are compared with chromatograms of polystyrene standards obtained in the same conditions in chloroform. All polymer chromatograms show a narrow molar mass distribution. Elution peaks of the polymer correspond to peaks obtained for the standards with high molar mass ranging from 2×104 to above 2×106 g/mol. 1H NMR Spectra at 200 MHz show no loss of double bonds in the polymer, nor any presence of tertiary proton. This results indicate that the polymer is linear and branching or cross-linking, if present, cannot be detected. Spectra obtained through 13C NMR spectrometry at 22.63MHz allow the determination of the proportion of cis and trans configurations.

Background: In embryological culture dishes, there is a TEMPERATURE decline when they are removed outside incubators. This study aimed at investigating the effects of this TEMPERATURE decline within a certain time frame, the type of culture dish with or without the use of laminar air flow and whether it is possible to achieve a sufficient thermal control with the use of a heating stage. Materials and Methods: In this experimental study, the TEMPERATUREs of four different types of polystyrene dishes [50 mm intracytoplasmic sperm injection (ICSI), 35 mm, 60 mm, 90 mm], filled with culture medium and oil were recorded for a period of 10 minutes outside the incubator. TEMPERATURE was measured with an infrared thermographic camera. The reference TEMPERATURE was 37° C. Four parameters were analyzed: the type of dishes, air flow, a heating stage at 37° C and 38. 5° C. Results: There was a time-dependant significant TEMPERATURE decline outside the incubator in all types of dishes and under all experimental conditions. Under air flow TEMPERATURE decline increased compared to the no air flow condition. The use of a heating stage at either 37° C or 38. 5° C slightly improved the situation in most cases. After three minutes out of the incubator without a heating stage and air flow, the TEMPERATURE was <34° C; with air flow and without a heating stage the TEMPERATURE was <33° C. When a heating stage was used, the TEMPERATURE was <36° C, except when using ICSI dishes. When ICSI dishes were on a heating stage they maintained a TEMPERATURE close to 37° C with or without air flow. In all experimental conditions the highest decline was recorded with the 90 mm dishes. Conclusion: Time is crucial for managing the TEMPERATURE decline in culture dishes when out of the incubator. Under air laminar flow, the heat loss is greater, when with a heating stage at 37° C or better at 38. 5° C this loss decreases but still exists. ICSI flat bottom dishes give the best results when heated stages are used. Flat bottom dishes maintain the TEMPERATURE rather efficiently. Based on our findings, the use of flat bottom dishes should become a universal practice in in vitro fertilization (IVF).

In this paper the density and TEMPERATURE dependencies of surface tension are investigated. Using the Lennard-Jones (12, 6), as an effective pair interaction potential, a linear expression is derived for isotherms of g /r2 versus r2 for some normal and ChloroFluoroCarbons (CFCs) fluids, where g is surface tension and r=1/v is molar density. The linearity behavior of the derived equation is well fitted onto the experimental data of surface tension for monatomic, diatomic, nonpolar, polar, hydrogen-bonded and chlorofluorocarbons. In addition, the TEMPERATURE dependence of surface tension for 20 different fluids is examined, in which the contributions of both terms of the average effective pair potential to theg are determined. For all liquids investigated in this work, surface tension increases with density except for water. The surface tension of water for isotherms within 280-300 K decreases with density, whereas increases within the range of 310-320 K.