Effects of Shoal Margin Collapses on the Morphodynamics of a Sandy Estuary.

Shoal margin collapses of several million cubic meters have occurred in the Western Scheldt estuary, the Netherlands, on average five times a year over the last decades. While these collapses involve significant volumes of material, their effect on the channel-shoal morphology is unknown. We hypothesize that collapses dynamicize the channel-shoal interactions, which could impact the ecological functioning, flood safety, and navigation in the estuary. The objective is to investigate how locations, probability, type, and volume of shoal margin collapse affect the channel-shoal dynamics. We implemented an empirically validated parameterization for shoal margin collapses and tested its effect on simulated estuary morphological development in a Delft3D schematization of the Western Scheldt. Three sets of scenarios were analyzed for near-field and far-field effects on flow pattern and channel-shoal morphology: (1) an observed shoal margin collapse of 2014, (2) initial large collapses on 10 locations, and (3) continuous collapses predicted by our novel probabilistic model over a time span of decades. Results show that a single shoal margin collapse only affects the local dynamics in the longitudinal flow direction and dampen out within a year for typical volumes, whereas larger disturbances that reach the seaward or landward sill at tidal channel junctions grow. The direction of the strongest tidally averaged flow determined the redistribution of the collapsed sediment. We conclude that adding the process of shoal margin collapses increases the channel-shoal interactions and that in intensively dredged estuaries shoal margins oversteepen, amplifying the number of collapses, but because of dredging the natural morphological response is interrupted.

The apgar score and its components in the preterm infant.

OBJECTIVE: The Apgar score is well-characterized in full-term infants but not in premature infants. The objective of this study was to assess the Apgar score in preterm infants with respect to the relationships between the 1- and 5-minute scores, the correlation of the Apgar score with pH and with other variables, and the relationship among the individual Apgar components. METHODOLOGY: We recorded Apgar scores at 1 and 5 minutes in a population-based cohort of preterm infants (n = 1105) with birth weight <2000 g, from three intensive care nurseries in central New Jersey. Linear correlation analysis was used to examine the relationship between 1- and 5-minute Apgar scores and between the individual components of the Apgar score. Multiple regression analysis was used to explore the relationship between various perinatal characteristics and the Apgar score, and between pH and Apgar score. Stepwise logistic regression analysis was used to assess the determinants of mortality. RESULTS: The 1-minute Apgar score median (25%, 75%) was 6(4,8) and correlated with the 5-minute score of 8(7,9) at r = .78. Slight but significant differences were seen between male (n = 557) and female (n = 508) infants in the 1-minute (6[4,8] and 7[4,8]) Apgar scores. One- and 5-minute scores of white infants (7[4,8] and 8[7,9]; n = 713) were significantly higher than those of black infants (5[3,7] and 8[6,9]; n = 280). Birth weight and gestational age were both linearly related to both Apgar scores. Low Apgar score (<3 at 1 minute and <6 at 5 minutes) was significantly associated with birth weight, gestational age and mode of delivery. Low arterial blood pH (<7.01) at birth was significantly related to low Apgar score. One hundred fifty-nine infants died; these infants were significantly smaller (983 +/- 382 vs 1462 +/- 369 g), less mature (27 vs 31 weeks), had lower arterial blood pH (7.20 +/- 0.18 vs 7.31 +/- 0.11), had lower 1- (3[2,6] vs 7[4,8]) and 5-minute Apgar scores (6[4,8] vs 8[7,9]), and a greater incidence of low Apgar score (32% vs 6%) than did survivors. CONCLUSIONS: Among the components of the Apgar score, respiratory effort, muscle tone, and reflex activity correlated well with one another; heart rate correlated less well; and color the least. Our data confirms the limited use of the Apgar score in preterm infants and demonstrates the different responses of the Apgar score's components.

Blood pressure ranges in premature infants: II. The first week of life.

OBJECTIVE: To examine the arterial blood pressure in the first week of life in a healthy premature population. DESIGN: Population-based cohort study. SETTING: Three intensive care nurseries in central New Jersey. PATIENTS: Premature infants with birth weights less than 2000 g. MAIN OUTCOME MEASURES: We documented daily maximum and minimum systolic and maximum and minimun diastolic blood pressures during the first 7 days of life. To examine the effects on the ranges of blood pressure, we identified four groups of infants: (1) healthy infants without any of the major risk factors (n = 193); (2) infants who were mechanically ventilated but free of any of the other conditions (n = 225); (3) infants with histories of maternal hypertension or preeclampsia (n = 38) and (4) infants with low Apgar scores (less than 3 at 1 minute and less than 6 at 5 minutes) regardless of the presence of other conditions (n = 86). RESULTS: Blood pressure increased steadily in the first week of life in all four groups. There was no relationship between any of the four blood pressure variables, or trends in blood pressure over time, with birth weight, gender, or race. Regression equations (based on all infants with available data) for blood pressure ranges by day of life revealed that the maximum systolic blood pressure increased by 2.6 mm Hg/d, the minimum systolic blood pressure increased by 1.8 mm Hg/d,the maximum diastolic blood pressure increased by 2.0 mm HHg/d, and the minimum diastolic blood pressure increased by 1.3 Hg/d. CONCLUSIONS: Infants with birth asphyxia and ventilated infants had significantly lower systolic and diastolic blood pressures than healthy infants.

Umbilical vein interleukin 6 and tumor necrosis factor alpha plasma concentrations in the very preterm infant.

OBJECTIVE: To examine the relationship between umbilical vein plasma concentrations of interleukin 6 (IL-6) and tumor necrosis factor (TNF)-alpha and early neonatal sepsis in the very preterm infant, and the histopathologic findings of chorioamnionitis in the placentas from these pregnancies. METHODS: A prospective study was conducted in 43 very preterm, singleton infants delivered at or before 32 weeks of gestation. IL-6 and TNF-alpha were measured by enzyme-linked immunoassay. Placentas from these pregnancies were histologically examined for the presence of chorioamnionitis. Infants were prospectively classified as confirmed sepsis group, clinical sepsis group or control group. IL-6 and TNF-alpha plasma concentrations were not normally distributed, so they were transformed to their natural log values for statistical analysis. RESULTS: The enrolled infants had a mean gestational age of 27.2 +/- 2.7 weeks and a mean birth weight of 956 +/- 325 g. Three (7%) infants had confirmed sepsis, 18 (42%) were in the clinical sepsis group and 22 (51%) were in the control group. IL-6 concentrations but not TNF-alpha were significantly higher (P < 0.05) in the confirmed (8.9 +/- 1.7) and clinical sepsis (5.5 +/- 2.4) groups in comparison with the control group (2.1 +/- 1.6). We examined 42 placentas. Twenty-three (55%) had no evidence of chorioamnionitis, 1 (2%) had mild grade, 8 (19%) had a moderate grade and 10 (24%) had a severe grade of chorioamnionitis. IL-6 was significantly elevated in the moderate (5.9 +/- 1.6 vs. 1.9 +/- 1.6) and severe grade (7.2 +/- 2.3 vs. 1.9 +/- 1.6) of chorioamnionitis, in the presence of acute deciduitis (6.0 +/- 2.7 vs. 2.1 +/-1.8), chorionic vasculitis (6.8 +/- 2.1 vs. 2.2 +/- 1.9) and funisitis (7.3 +/- 1.9 vs. 2.7 +/- 2.3) (P < 0.05) TNF-alpha plasma concentrations were not significantly different. CONCLUSION: An elevated umbilical vein IL-6 concentration is a good indicator of sepsis syndrome in the very preterm infant and also correlates with histologic chorioamnionitis in these pregnancies.

Antioxidant capacity and oxygen radical diseases in the preterm newborn.

BACKGROUND: Bronchopulmonary dysplasia, intraventricular hemorrhage, necrotizing enterocolitis, and retinopathy of prematurity may be different manifestations of oxygen radical diseases of prematurity (ORDP). OBJECTIVE: To test the hypothesis that the antioxidant capacity of cord blood serum will predict risk of ORDP. DESIGN: An inception cohort of premature neonates was followed up from birth until discharge or death to determine if outcome was related to cord blood serum antioxidant capacity, as determined by a manual assay measuring the relative inhibition of oxidation of 2,2'-azino-di-(3-ethylbenzthiazoline)-6 sulfonic acid (ABTS). Possible correlations between antioxidant capacity and various perinatal factors were also tested. SETTING: Level 3 newborn intensive care unit. PATIENTS: All inborn very low-birth-weight neonates from whom cord blood was available and for whom maternal consent was obtained were included. Newborns who died in the first week of life or who had major congenital malformations were excluded. A convenience sample of newborns weighing more than 1500 g was used to perfect assay and explore confounders. MAIN OUTCOME MEASURES: Significant ORDP was defined as the presence of intraventricular hemorrhage greater than grade 2, retinopathy of prematurity greater than stage 1, bronchopulmonary dysplasia at the postconceptional age of 36 weeks, or necrotizing enterocolitis with the hypothesis that neonates with ORDP will have lower antioxidant capacity in cord blood serum. RESULTS: Serum antioxidant capacity at birth correlated with gestational age for the entire sample of 41 neonates and for the 26 neonates born before 32 weeks' gestation. After correction for gestational age, cord serum antioxidant capacity did not correlate with maternal smoking, preeclampsia, chorioamnionitis, cord pH Apgar scores, or any of the ORDP studied. CONCLUSION: Cord serum antioxidant capacity correlates with gestational age but does not predict ORDP risk.

Urinary thiobarbituric acid-reacting substances as potential biomarkers of intrauterine hypoxia.

BACKGROUND: Currently available clinical tools cannot accurately identify the extent of perinatal hypoxic injuries. During hypoxia, reactive oxygen species cause lipid peroxidation of cell membranes, yielding oxidation products that constitute thiobarbituric acid-reacting substances (TBARS). OBJECTIVE: To see if the concentrations of TBARS excreted in urine would be elevated during the first day of life in term and preterm infants following chronic hypoxia or acute asphyxia. DESIGN: Thiobarbituric acid-reacting substances levels were measured by a spectrophotometric assay in urine samples collected from term and near-term (>/= 34 weeks gestation, n = 22), and preterm (<34 weeks gestation, n = 52) infants on the first day of life. PATIENTS: Infants were admitted to the St Peter's University Hospital (New Brunswick, NJ) neonatal intensive care unit from July 1997 to January 1999. Acute asphyxia was defined as umbilical cord blood pH values less than 7.05, or Apgar scores of less than 5 at 5 minutes. Chronic hypoxia was defined as intrauterine growth retardation or low birth weight (small for gestational age) associated with pregnancy-induced hypertension or reversal of umbilical arterial blood flow. RESULTS: Among term infants, urinary TBARS levels were significantly increased following acute asphyxia (P =.02). Levels of TBARS also tended to be elevated following chronic hypoxia. Urinary TBARS levels in term infants tended to be increased in those requiring mechanical ventilation (P =.05) or delivery room resuscitation (P =.15), as well as in those passing intrauterine meconium (P =.13) or having clinical evidence of hypoxic-ischemic encephalopathy (P =.24). CONCLUSIONS: The results show a correlation between elevated urinary TBARS levels in term and near-term infants, and perinatal hypoxia (as determined by low Apgar scores or umbilical cord blood acidosis). We speculate that TBARS concentrations may be useful as a biomarker for perinatal hypoxic injury in newborns. Further studies are needed to determine whether elevations in TBARS levels are better predictors of the extent of hypoxic injury than existing markers.

Antecedents and neonatal consequences of low Apgar scores in preterm newborns: a population study.

BACKGROUND: To examine the antenatal and early neonatal correlates of low Apgar scores (<3 and <6 at 1 and 5 minutes) in preterm newborns (23-34 weeks' gestation). OBJECTIVE: The use of Apgar scoring for premature newborns remains widespread, despite controversy regarding its reliability as a measure of morbidity and mortality in the neonatal period. DESIGN: A cohort of 852 preterm newborns born during a 34-month period between 1984 and 1987 was studied. Newborns were stratified into 2 groups by gestational age (23-28 weeks and 29-34 weeks), and data were analyzed, controlling for gestational age in single weeks. SETTING: Two academic and 1 community hospital, which together accounted for 83% of all preterm births in a tri-county area of central New Jersey during the study period. PATIENTS: All premature newborns (birth weight <2000 g and gestational age <35 weeks) born in the participating hospitals during the study period were evaluated. MAIN OUTCOME MEASURES: Antecedents included maternal illness during pregnancy, maternal complications of labor and delivery, and fetal heart rate abnormalities during labor and delivery. Consequences included delivery room resuscitation, abnormal physical findings, diagnoses, and therapeutic interventions in the first 6 to 8 hours of life. RESULTS: Premature newborns with low Apgar scores received more cardiopulmonary resuscitation in the delivery room and in the first 6 to 8 hours of neonatal intensive care. Mortality was significantly increased among newborns with low Apgar scores (54% vs. 26% in the 23- to 28-week stratum, 30% vs 6% in the 29- to 34-week stratum). Newborns with low Apgar scores in the 29- to 34-week stratum more often required intubation, positive pressure ventilation, and umbilical vessel catheterization. Newborns with low Apgar scores had higher rates of bradycardia, pneumothoraces, acidosis, and increased oxygen requirement during the first 6 to 8 hours of life. Maternal illness, complications of labor and delivery;, and fetal heart rate decelerations did not correlate with subsequent Apgar scores of newborns. The presence of severe bradycardia (<90/min) and fetal heart rate accelerations correlated with low Apgar scores in the 29- to 34-week group. CONCLUSION: Low Apgar scores are associated with increased neonatal morbidity and mortality in preterm newborns. Antenatal maternal history, and pregnancy complications are not clearly associated with low Apgar scores. Therefore, the Apgar score is a useful tool in assessing neonatal short-term prognosis and the need for intensive care among preterm newborns.

Effect of storage on breast milk antioxidant activity.

BACKGROUND: Human milk, which contains compounds beneficial to infants, is often expressed and stored before use. Changes in its antioxidant activity with storage have not been studied. OBJECTIVES: To measure antioxidant activity of fresh, refrigerated (4 degrees C), and frozen human milk (-20 degrees C), stored for two to seven days; to compare the antioxidant activity of milk from mothers delivering prematurely and at term; to compare the antioxidant activity of infant formulas and human milk. METHODS: Sixteen breast milk samples (term and preterm) were collected from mothers within 24 hours of delivery and divided into aliquots. Fresh samples were immediately tested for antioxidant activity, and the rest of the aliquots were stored at -20 degrees C or 4 degrees C to be analysed at 48 hours and seven days respectively. The assay used measures the ability of milk samples to inhibit the oxidation of 2,2'-azino-di-3-(ethylbenzthiazolinesulphonate) to its radical cation compared with Trolox. RESULTS: Antioxidant activity at both refrigeration and freezing temperatures was significantly decreased. Freezing resulted in a greater decrease than refrigeration, and storage for seven days resulted in lower antioxidant activity than storage for 48 hours. There was no difference in milk from mothers who delivered prematurely or at term. Significantly lower antioxidant activity was noted in formula milk than in fresh human milk. CONCLUSIONS: To preserve the antioxidant activity of human milk, storage time should be limited to 48 hours. Refrigeration is better than freezing and thawing.

The ventilatory response to carbon dioxide in high risk infants.

PURPOSE: To examine the ventilatory response to inspired carbon dioxide in infants considered to be at risk for sudden infant death syndrome or apnea. DESIGN: Clinical data measurement. SETTING: Infant apnea evaluation program of a university division of neonatology. PATIENTS: Fifty nine infants were full term characterized by the following diagnoses; siblings of infants who had died from sudden infant death syndrome (SIDS) (n = 7), apparent life threatening event (ALTE) (n = 24), apnea/cyanosis in the newborn nursery (n = 21), and controls. Sixty-nine infants were preterm and consisted of patients suffering from idiopathic apnea (n = 61), and bronchopulmonary dysplasia (n = 8). MEASUREMENTS: The ventilatory response to carbon dioxide was measured with a computerized waveform analyzer. MAIN RESULTS: Among full term infants no significant differences in the ventilatory slope in response to CO2 was seen. The range of mean slope was 19.4 +/- 7.6 in siblings of SIDS and 36 +/- 17 in control infants. Greater number of sibling of SIDS had slopes less than 20 ml/kg/min/mmHg in comparison to control infants. Sibling of SIDS had less increase in minute ventilation and inspiratory flow in response to CO2 administration in comparison to control infants. Preterm infants had similar slopes with a mean of 33 ml/kg/min/mmHg in infants with idiopathic apnea and 28 ml/kg/min/mmHg in infants with bronchopulmonary dysplasia. CONCLUSIONS: The large intragroup variability in the ventilatory response to inspired CO2, confirming previously reported data, comprises the benefit of this test. Thus, ventilatory response to CO2 administration is not useful in unselected patients at risk of SIDS or apnea.

The protective role of bilirubin in oxygen-radical diseases of the preterm infant.

We hypothesized that because bilirubin is a potent free-radical quencher, infants without disorders that have oxygen-radical disease (ORD)-mediated mechanisms may have higher bilirubin levels than infants suffering from conditions possibly associated with ORD-mediated mechanisms (e.g., necrotizing enterocolitis, broncopulmonary dysplasia, intraventricular hemorrhage, and retinopathy of prematurity). We identified 25 infants (birth weight 912 +/- 208 gm, gestational age 27 +/- 3 weeks) who comprised the ORD group and compared them with 57 controls (birth weight 1242 +/- 248 gm, gestational age 31 +/- 3 weeks). Infants with ORD had lower peak serum bilirubin concentrations, later ages at peak, and lower incidence of peak bilirubin concentrations exceeding 10 or 15 mg/dl. In addition, these infants exhibited a slower rate of bilirubin rise and a smaller area under the bilirubin-time curve measure compared with controls. To control for different birth weights, we analyzed subgroups weighing < 1000 gm. Significant differences were again identified in peak bilirubin concentrations, age at peak, phototherapy duration, and area under the curve. In this population of preterm infants, higher bilirubin levels were associated with a lower incidence of oxygen radical-mediated injury.

Heart rate and oxygen saturation correlates of infant apnea.

OBJECTIVE: To analyze the effects of apnea duration on changes in heart rate and oxygen saturation and to examine the temporal relationships among these variables. STUDY DESIGN: An event analysis sheet was designed to analyze numerous variables reflecting changes in heart rate and oxygen saturation associated with infant apnea. From July 1, 1991 through June 30, 1992 we identified 32 infants enrolled in The Infant Apnea Program at St. Peter's Medical Center, New Brunswick, NJ who had apnea > or = 15 seconds in duration on consecutive 12-hour multichannel recordings of heart rate, thoracic impedance, nasal thermistry, and oxygen saturation. The apnea epochs of these patients were subdivided into apnea of short (10 to 14 seconds), medium (15 to 19 seconds), and long (> or = 20 seconds) duration, and a total of 236 apnea epochs were analyzed. The significance of differences was assessed by analysis of variance and Newman-Keuls multiple comparisons. RESULTS: We found that the duration of apnea has significant effects on perturbations in both heart rate and oxygen saturation, however, the degree of oxygen desaturation can not be predicted by the perturbation in heart rate. Analysis of the temporal relationship of apnea, bradycardia, and oxygen desaturation reveals that, although apnea precedes both heart rate and oxygen saturation drops in most infants as the length of apneic interval increases, the interval between apnea onset and associated drops in heart rate and/or oxygen saturation also increases. CONCLUSION: Oxygen saturation monitoring may provide important physiologic data that can not be assessed by cardiorespiratory monitoring alone.

Maternal grief after sudden infant death syndrome.

Six months after the death of their infants of Sudden Infant Death Syndrome (SIDS), the subjective impression of mothers anonymously rating their initial and present grief was that there had been a reduction in all symptoms (p < .001). However, an increase in the relative ranking of some cognitive symptoms over somatic ones, the association of certain lifestyles and situational variables with higher levels of grief, and the implication for future symptoms of family decisions made during bereavement underscore the importance of continuing active support for these families. In relative ranking, guilt rose from 10th to 5th most prominent symptom, particularly among the 34% of mothers whose infants manifested clinical symptoms (p < .05). Single mothers had higher grief scores both initially (p < .05) and at 6 months (p < .002), were almost three times more likely to become pregnant within 6 months of the death but only one-third as likely to attend a support group, and were also more likely to move after the death (44% vs 25%). Mothers whose infants had been discovered by another caregiver reached out more to a crisis intervention service of a support program available to SIDS families (p < .05). Mothers without surviving children had grief levels comparable with those with children but were less likely to rate their pediatrician's support as satisfactory, increasing the probability that they would change physicians with subsequent children, thereby losing continuity of care and support.

Esophageal perforation in the neonate: an emerging problem in the newborn nursery.

We report 11 cases of esophageal perforation in the neonate, in whom no surgery was performed for repair of the perforation, nor was any cervical or mediastinal drainage carried out. The perforation was in the cervical esophagus in all cases where an esophagram was performed. Nine were in premature babies (580 to 1,350 g), and two were full-term babies. There were two deaths in small prematures (580 and 935 g), from extreme prematurity and intraventricular hemorrhage, with no morbidity or mortality related to the esophageal perforation. The babies presented as esophageal atresia, or pneumothorax with the feeding tube in the right chest, or an abnormal right upper extrapleural air collection with infiltrate. Barium esophagram showed a classic "double esophagus" configuration. Two babies were mistakenly operated on, one with a diagnosis of esophageal duplication, and one had a gastrostomy for a diagnosis of esophageal atresia. Esophageal perforation in the neonate is an iatrogenic disease that may mimic esophageal atresia, and may be managed without surgical intervention.

Nurses' assessments and management of pain in children having orthopedic surgery.

The specific aims of this research project were to (a) describe selected verbal, nonverbal, and physiological arousal indicators of the child's pain; (b) describe which pain indicators were most influential to nurses in decision-making about interventions for managing the child's pain; (c) describe pain interventions used by nurses; (d) compare postoperative analgesic orders to recommended dosages for the children; and (e) explore relationships between the child's self-report of pain and medication dosages administered. Subjects included 19 children aged 5-17 years who experienced 20 orthopedic surgical procedures (one child had two surgeries one week apart). Data were collected by staff nurses for the first five days after surgery. Pain levels were reported using the Oucher Scale. Postoperative pain was reported at moderate levels and showed only a gradual decrease throughout the hospital stay. Nonverbal pain indicators included crying and tense face. The child's complaint of pain and reported Oucher scores were most influential in influencing nurses to intervene in the child's pain. Nonpharmacological comfort measures included positioning and reassurance. All children received medications for pain; 49% of the orders were within the recommended therapeutic dosage range. A small but significant correlation was found between the child's reported pain level and the morphine equivalents of pain medication received. Recommendations included development of nursing flow charts that provide space to record pain levels and nursing interventions, in-service education for nurses on nonpharmacological interventions, and further research with a larger sample and a single pain rating scale.

The length of time necessary to break even after converting to digital mammography.

The cost differences between film-based mammography (FBM) and digital mammography (DM) were estimated after discussions with hospital personnel and industry representatives. Human resource costs were not included. The fixed cost of FBM per machine was estimated to be $50,000 and the variable cost $4.60 per examination. The fixed cost of DM per machine was estimated to be $102,000 and the variable cost $0.10 per examination. The total number of examinations required to break even was therefore 11,556. At a rate of 15 examinations per machine per day and with 251 working days per year, it would take 3.1 years to break even. In the first year after the break-even point had been attained, $16,943 would be saved for every 3765 examinations performed. Extrapolating to the USA as a whole, in which 23 million mammographic examinations are performed each year, suggests that the annual savings from going filmless would be more than $103 million.

Auditory and visual recall of forward and backward digit spans.

Increasingly, clinicians obtain data from tests across modalities. Little actual information, however, exists as to normal patterns. An example is auditory and visual recall of digit span. The effects of modality on recall of digit span, sequence, and order were examined with 80 subjects (M age 24.3 yr.). Subjects were given the Wechsler Adult Intelligence Scale-Revised, and a research version of MicroCog: Assessment of Cognitive Functioning. Both contain forward and backward digit spans. Recall for visual presentation was significantly stronger than for auditory presentation of backward digit span. Recall for visual backward digit span was also superior to auditory backward digit span when the sequence of presentation was controlled. The mean number of digits recalled was higher when visual digit span was preceded by auditory digit span.

Bioconcentration factors for volatile organic compounds in vegetation.

Samples of air and leaves were taken at the University of Nevada [Formula: see text] Las Vegas campus and analyzed for volatile organic compounds using vacuum distillation coupled with gas chromatography/mass spectrometry. The data were used to estimate the bioconcentration of volatile organic compounds (VOCs) and to characterize the equilibration of VOCs between the leaves and air. The bioconcentration of volatiles in the leaves of some species can be predicted using the partition coefficients between air and octanol (K(oa)) and only considering VOC absorption in the lipid fraction of leaves. For these leaves, the bioconcentration factors agreed with existing models. Leaves of some species displayed a bioconcentration of volatiles that greatly exceeded theory. These hyperbioconcentration leaves also contain appreciable concentrations of monoterpenes, suggesting that a terpenoid compartment should be considered for the bioconcentration of organic compounds in leaves. Adding an additional "terpenoid" compartment should improve the characterization of volatile organic compounds in the environment. The uptake of VOCs from air by leaves is rapid, and the equilibration rates are seen to be quicker for compounds that have higher vapor pressures. The release of VOCs from the leaves of plants is slower for hyperbioconcentration leaves.