Micron-size tire tread particles leach organic compounds at higher rates than centimeter-size particles: Compound identification and profile comparison.

Tire tread particles (TTP) are environmentally prevalent microplastics and generate toxic aqueous leachate. We determined the total carbon and nitrogen leachate concentrations and chemical profiles from micron (∼32 µm) and centimeter (∼1 cm) TTP leachate over 12 days. Dissolved organic carbon (DOC) and total dissolved nitrogen (TDN) were used to measure the concentration of leached compounds. Nontargeted chemical analysis by comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC×GC/TOF-MS) was used to compare the chemical profiles of leachates. After leaching for 12 days, DOC was 4.0 times higher in the micron TTP leachate than in the centimeter TTP leachate, and TDN was 2.6 times higher. The total GC×GC/TOF-MS chromatographic feature peak area was 2.9 times greater in the micron TTP leachate than the centimeter TTP leachate, and similarly, the total relative abundance of 54 tentatively identified compounds was 3.3 times greater. We identified frequently measured tire-related chemicals, such as 6PPD, N-cyclohexyl-N'-phenylurea (CPU), and hexa(methoxymethyl)melamine (HMMM), but nearly 50% of detected chemicals were not previously reported in tire literature or lacked toxicity information. Overall, the results demonstrate that smaller TTP have a greater potential to leach chemicals into aquatic systems, but a significant portion of these chemicals are not well-studied and require further risk assessment.

Pulsatile expansion therapy for orbital enlargement.

Experimental and clinical investigations have documented the modulatory role of the globe in the development of the orbit. In cases of absence or early loss of the globe, severe hypoplasia of the orbit and midface has been reported by several authors. Statical conformers and orbital osteotomies have been used to correct the resulting facial asymmetry. When replacing such conformers by increasingly larger ones, orbital structures are negatively influenced by the repeated trauma of surgical interventions. Simulating the modulatory role of the globe on orbital growth was the objective when developing a pulsatile device for orbital enlargement in cases of anophthalmia and microrbitism. The design, application and preliminary experience with a dynamic, pulsatile expanding system are presented.

Familial aggregates in obstructive sleep apnea syndrome.

Obstructive sleep apnea syndrome (OSAS) was diagnosed in157 subjects based on clinical symptoms, physical evaluation, cephalometric x-ray films, and polysomnography. These index cases identified 844 living first-degree relatives. Mailings were sent to 792 (94%). The mailing consisted of two identical questionnaires, one for the family member of the index case and one to be given to a friend (not a relative) of approximately the same age. In response, we received 531 (63%) questionnaires from relatives and 198 (25%) questionnaires from age-matched nonrelated friends, which were used as a control group. A more extensive investigation was performed on first-degree relatives of the index group living in the San Francisco Bay Area or vicinity. Two hundred seventy-nine relatives (100%) were identified. One hundred sixty-six subjects (59%) as well as 69 age-matched friends (ie, 41% of the 166 relatives and 25% of the potential total group) agreed to participate in further studies. These subjects had interviews, clinical investigations, and nonattended ambulatory monitoring. Cephalometric x-ray films could be obtained on only 22 of 166 participating relatives and 6 of 69 friends. Body mass index was not a differentiating measure between relatives and friends. Odds ratios (ORs) were calculated from the questionnaiare data. The report of tiredness, fatigue, and sleepiness did not distinguish family members from friends. The OR, however, progressively increases when there is a positive history of near nightly loud snoring (OR = 1.78; 95% confidence interval [CI] 1.25-2.54) or a positive history of daytime sleepiness in conjunction with near nightly loud snoring (OR = 3.11; 95% CI = 1.94-4.99). The investigation in the Bay Area indicated that, when first-degree relatives were compared with friends, the complaint of daytime tiredness, sleepiness, or both with the presence of a high and narrow(ogival) hard palate sharply differentiated between friends and relatives (OR = 10.9, 95, CI = 5.31-22.5). An Epworth Sleepiness Scale score of 9 or greater with the presence of another symptom associated with OSAS, and a respiratory disturbance index greater than 5 (number of apneas and hypopneas per hour of sleep > 5) gave an OR of 45.6 (95% CI = 18.8-11.0). Disproportionate craniofacial anatomy was common in familial groups with OSAS. Craniofacial familial features can be a strong indicator of risk for the development of OSAS.