Optically tunable chirped fiber Bragg grating.

This work presents an optically tunable chirped fiber Bragg grating (CFBG). The CFBG is obtained by a side-polished fiber Bragg grating (SPFBG) whose thickness of the residual cladding layer in the polished area (D(RC)) varies with position along the length of the grating, which is coated with a photoresponsive liquid crystal (LC) overlay. The reflection spectrum of the CFBG is tuned by refractive index (RI) modulation, which comes from the phase transition of the overlaid photoresponsive LC under ultraviolet (UV) light irradiation. The broadening in the reflection spectrum and corresponding shift in the central wavelength are observed with UV light irradiation density of 0.64mW/mm. During the phase transition of the photoresponsive LC, the RI increase of the overlaid LC leads to the change of the CFBG reflection spectrum and the change is reversible and repeatable. The optically tunable CFBGs have potential use in optical DWDM system and an all-fiber telecommunication system.

Relationship between urinary tract infection and contraceptive methods.

To investigate the relationship between urinary tract infection (UTI) and contraceptive methods, a comparative survey of contraceptive methods and frequency of intercourse was conducted among young women with and without confirmed UTI. Women with a documented UTI had more frequent intercourse than those without infection. There was a statistically significant positive correlation between frequency of intercourse and UTI. When frequency of intercourse was statistically controlled for, there were no significant differences between those with and those without UTI regarding the type of contraceptive method used.

PIP: To investigate the relationship between urinary tract infection (UTI) and contraceptive methods, a comparative survey of contraceptive methods and frequency of intercourse was conducted among young women with and without confirmed UTI in a US city. The UTI group was composed of 54 women, age 18-23 years. The non-UTI group was composed of 54 women, age 17-23 years. Subjects presented to a university student health center in New York State. A self-administered, anonymous questionnaire was used to determine contraceptive methods and frequency of intercourse for past week and past month. Women with a documented UTI had more frequent intercourse than those without infection. There was a statistically significant positive correlation between frequency of intercourse and UTI. When frequency of intercourse was statistically controlled for, there were no significant differences between those with and those without UTI regarding the type of contraceptive method used. The precise mechanism for the development of postcoital infection is not known. It may be that the mechanical action of intercourse facilitates bacterial entry into the bladder. An alternate explanation is that intercourse, through local irritation, causes dysuria, which prompts a woman to seek care.