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Broadband dielectric spectroscopy (10 Õ 2 ± 10 5 Hz) is used to study the opto-dielectric e ect in statistical polysiloxane copolymers with side groups containing chiral mesogenic units and others containing azobenzene moieties. Below 64ß C, the unexposed copolymer is ferroelectric. UV-exposure induces a photoisomerization of the azobenzene to the cis-con® guration, and the phase transition, ferroelectric/non-ferroelectric (S * C/SA ), is shifted to lower temperatures. In the temperature interval between the phase transition temperatures ferroelectric/nonferroelectric of the exposed and unexposed samples, an opto-dielectric e ect is observed. The e ciency of this opto-dielectric switching depends on the packing of the chromophore within the smectic layers.

The routine spermiogram parameters of 3432 patients born between 1952 and 1971 in the region of Leipzig were determined between January 1975 and March 2000. The patient group aged 24-35 years was characterized by low mobility and relocation living in the main centre of chemical industry with enormous environmental pollution in Eastern Germany up to 1990. Sperm concentrations and total sperm counts were found to be significantly reduced in men born between 1960 and 1970 compared with men born before this period (52.38 +/- 1.21 versus 70.79 +/- 2.15 millions ml(-1) 139.51 +/- 3.66 versus 176.31 +/- 6.04 millions; mean +/- SEM; P < 0.01; 2410 versus 1022 patients) independently of the year of semen examination.

Background: A new data base system was applied to analyse our patient group with two aims: (a) to analyze the effects of former cryptorchidism on the fertility of our infertility patients in comparison with the data of the literature and (b) to evaluate this system in a clinical study. Materials and Methods: Using the electronic data base Winsperm 2000^®, 1,648 infertility patients, 79 patients with testicular cancer and 201 healthy semen donors were examined. Results: A history of cryptorchidism, treated at 6.8 ± 3.3 years of life, was found in 10.1% of our infertility patient group. The routine spermiogram parameters, as well as basal hormone concentration of FSH, LH and testosterone, differed significantly from those of the healthy semen donor group. Comparison between patients with former unilateral and bilateral cryptorchidism differed significantly only in total sperm count. 27.7% of patients with a history of unilateral and 5.4% of patients with a history of bilateral cryptorchidism showed a sperm concentration within the normal range (p < 0.01). Azoospermia was detected in 13.1% of patients with unilateral cryptorchidism and in 29.7% of patients with former bilateral cryptorchidism (p < 0.05). The patients responding to our conception questionnaire realised a total conception rate of 46.1% in the ‘non-cryptorchidism group’ and of 20.6% in the ‘cryptorchidism-group’ (p < 0.05), whereas the conception rates did not differ between former unilateral and bilateral cryptorchidism (p > 0.05). Sixteen (20.3%) of the 79 patients with testicular neoplasm were previously treated for cryptorchidism. Conclusion: The results of our patient group underline the significance of former cryptorchidism for infertility and testicular neoplasm. The new data base system facilitates rapid data retrieval and examination.