Environmentally Adaptable and Temperature-Selective Self-Healing Polymers

Development of polymeric materials capable of self-healing at low temperatures is an important issue since their mechanical strength and self-healing performance are often in conflict with each other. Herein, random copolymers with self-healing capability in a wide temperature range prepared from 2-(dimethylamino)ethyl methacrylate (DMAEMA), glyceryl monomethacrylate (GlyMA), and butyl methacrylate monomers via free-radical polymerization and subsequent cross-linking with hexamethylene diisocyanate are reported. Wound closure is facilitated by swelling below the lower critical solution temperature or by heating above the glass transition temperature (T _g ) of the polymer. GlyMA units form metal-ligand coordination complexes with dibutyltin dilaurate, leading to the formation of new carbonate bonds under ambient CO₂ and H₂ O conditions. Although swelling/heating reduces the polymer's mechanical strength, it is fully restored following chemical re-bonding/drying at room temperature. The swelling and degree of scratch healing are affected by pH, temperature, and the DMAEMA content.

The clinical application of transcutaneous bilirubinometry in full-term Chinese infants

The pattern of jaundice in Chinese full-term newborns has seldom been explored. This study was to 1) investigate the correlation between transcutaneous bilirubin indices (TcB) and serum bilirubin levels; 2) use TcB to follow the pattern of jaundice in Chinese full-term newborns; and 3) compare the sensitivity and specificity of TcB measured from the forehead (TcB1), and mid-sternum (TcB2) by receiver operating characteristic curves (ROC curves). From April 1 to August 31, 1989, a total of 3217 TcB were obtained from 305 inborn full-term newborns (male 175, female 130) during their first 6 days of life. The correlation between serum bilirubin levels and TcB measured from the forehead (TcB1) and from the mid-sternum (TcB2) was good (r = 0.82 and 0.86 respectively). For formula-fed infants, both TcB1 (16.3 +/- 3.0) and TcB2 (16.6 +/- 2.7) reached peak levels at 78-84 hours of age, while in mixed-fed infants, peak levels were noted at 54-60 and 84-90 hours for TcB1 (17.2 +/- 2.2) and TcB2 (16.6 +/- 2.6) respectively. The incidence of hyperbilirubinemia was 5.9 per cent. There were no differences in peak TcB levels between formula-fed and mixed-fed infants. The ROC curves suggested that TcB2 is better than TcB1 in sensitivity and specificity. It is concluded that TcB is a reliable device for monitoring jaundice in Chinese full-term newborns. Peak level of jaundice occurred at the third to fourth day of age. The incidence of hyperbilirubinemia in Chinese infants has decreased, for reasons which need further investigation.

The effect of moderate non-hemolytic jaundice and phototherapy on newborn behavior

To study the effects of moderate non-hemolytic jaundice and phototherapy (PT) on newborn behavior, initially 29 full-term infants with serum bilirubin (SB) 12-15 mg/dl were randomly assigned to PT (n = 14) or non-PT (n = 15) group. PT was done until SB less than 12 mg/dl. One infant in the PT group was excluded because of G-6-PD deficiency and evidence of hemolysis. Four infants in the non-PT group were excluded because their serum bilirubin concentrations finally exceeded 15 mg/dl and they were put on phototherapy for ethical concern. Two more infants were then added to the non-PT group to make a total number of 13. Additional 14 infants with serum bilirubin levels less than 12 mg/dl were studied as controls. Neonatal Behavioral Assessment Scales (NBAS) were performed 4 times: just before PT, right after termination of PT, 24 hrs after termination of PT and at 2 wks of age in PT group, and at comparable ages with the non-PT and control groups. The course of jaundice was measured in terms of SB levels at entry into study, peak SB levels, duration from entry into study to the time when SB levels dropped below 12 mg/dl and age when SB levels dropped below 12 mg/dl. The values did not differ significantly between the PT and non-PT groups. Therefore, phototherapy did not change the clinical course of jaundice in the majority of infants with bilirubin levels between 12 and 15 mg/dl. The 7 cluster scores of 1st NBAS did not differ significantly among the 3 groups of infants. On the 2nd and 3rd examinations, the infants in the PT group performed poorer in some of the orientation items than the infants in the non-PT and control groups (p less than 0.05) whereas the non-PT groups showed similar performance as the control group. At 2 wks of age, no significant differences of the NBAS scores were found in 3 groups. We conclude that moderate non-hemolytic jaundice (serum bilirubin 12-15 mg/dl) does not affect the behavior of full-term infants in this study. Phototherapy has some short-term adverse effects on visual, auditory orientation and alertness of the infants which may impair infant-caregiver interaction.

[Parental attitude and adjustment to childhood epilepsy]

Parental attitude and adjustment were examined in 20 epileptic children (ages 6.8-16.6 yrs), using semi-structured interview. The results indicated that parental understandings of epilepsy were generally poor and incorrect. Fifteen (75%) of 20 parents had their own interpretations of causality and 19 (95%) had unrealistic hope for early and complete cure. Parents tended to overprotect and overrestrict their children. Sixteen (80%) concealed the illness for fear of social prejudice, therefore the social support systems were generally poorly utilized. As in other chronic diseases, all parents went through feelings of shock, denial, anger, guilt, fear, anxiety and depression. Family relationships were not affected much, however, poor communications were commonly found between parents and children. Thirteen (65%) parents never talked to their children about epilepsy. We concluded that parents of epileptic children showed negative attitudes toward their children and had difficulties in their psychosocial adjustment probably related to social stigmata and misunderstanding of the illness. Therefore, communication between physician and parents in both medical and psychosocial aspects should be encouraged.