instruction:
Given an abstract, generate a keyword (a noun phrase) that best describes the focus or contribution of the paper. Such keywords can be directly from the given abstract or outside it.
question:
Abstract: The electromagnetic spectrum consists of radiant energy that is classified according to specific wavelengths. Man is constantly exposed to a portion of the electromagnetic spectrum, particularly to radiation in the ultraviolet, visible and infrared regions. The tissues of the eye and skin are particularly sensitive to the non-ionizing wavelengths of radiant energy. Although both tissues possess endogenous protective mechanisms to minimize the effects of such exposure, problems still occur due to the absorption of radiation. The cornea, lens and retina have been shown to be susceptible to damage from light in the ultraviolet, visible and infrared range. Part I of this two-part article examines the structures of the eye that are most susceptible to light damage; part II, which will be published in the next issue of the Journal, focuses on eye protection.
answer:
Anterior Eye Segment

question:
Abstract: Papillomas of the respiratory and genital tracts are caused by the same papillomavirus genotypes, and mothers of children with respiratory papillomatosis often have a history of genital warts. Only one of 109 cases reviewed gave a history of birth by cesarean section, whereas ten cesarean deliveries would have been the expected number for this group on the basis of national rates. The single case was delivered by elective cesarean section before the rupture of the membranes, and the child developed respiratory papillomatosis in the first year of life. These findings suggest that in juvenile-onset disease, the transmission of infection from mother to child occurs most often during passage through an infected birth canal, but that intrauterine infection of the fetus is also possible. Papillomavirus infection of the female genital tract is common, but respiratory papillomatosis is rare. On the basis of crude estimates of annual number of children born to infected mothers and of new cases of juvenile-onset disease, the risk of developing disease for a child born to an infected mother was calculated to be one in several hundred exposures.
answer:
Cesarean Section

question:
Abstract: To test the hypothesis that occlusive apneas result from sleep-induced periodic breathing in association with some degree of upper airway compromise, periodic breathing was induced during non-rapid-eye-movement (NREM) sleep by administering hypoxic gas mixtures with and without applied external inspiratory resistance (9 cmH2O X l-1 X s) in five normal male volunteers. In addition to standard polysomnography for sleep staging and respiratory pattern monitoring, esophageal pressure, tidal volume (VT), and airflow were measured via an esophageal catheter and pneumotachograph, respectively, with the latter attached to a tight-fitting face mask, allowing calculation of total pulmonary system resistance (Rp). During stage I/II NREM sleep minimal period breathing was evident in two of the subjects; however, in four subjects during hypoxia and/or relief from hypoxia, with and without added resistance, pronounced periodic breathing developed with waxing and waning of VT, sometimes with apneic phases. Resistive loading without hypoxia did not cause periodicity. At the nadir of periodic changes in VT, Rp was usually at its highest and there was a significant linear relationship between Rp and 1/VT, indicating the development of obstructive hypopneas. In one subject without added resistance and in the same subject and in another during resistive loading, upper airway obstruction at the nadir of the periodic fluctuations in VT was observed. We conclude that periodic breathing resulting in periodic diminution of upper airway muscle activity is associated with increased upper airway resistance that predisposes upper airways to collapse.
answer:
Adult