Materials informatics for the screening of multi-principal elements and high-entropy alloys.

The field of multi-principal element or (single-phase) high-entropy (HE) alloys has recently seen exponential growth as these systems represent a paradigm shift in alloy development, in some cases exhibiting unexpected structures and superior mechanical properties. However, the identification of promising HE alloys presents a daunting challenge given the associated vastness of the chemistry/composition space. We describe here a supervised learning strategy for the efficient screening of HE alloys that combines two complementary tools, namely: (1) a multiple regression analysis and its generalization, a canonical-correlation analysis (CCA) and (2) a genetic algorithm (GA) with a CCA-inspired fitness function. These tools permit the identification of promising multi-principal element alloys. We implement this procedure using a database for which mechanical property information exists and highlight new alloys having high hardnesses. Our methodology is validated by comparing predicted hardnesses with alloys fabricated by arc-melting, identifying alloys having very high measured hardnesses.

Epidural labor analgesia and the incidence of cesarean delivery for dystocia.

UNLABELLED: We performed this retrospective study to examine the changes in cesarean delivery rates associated with the establishment of a labor epidural service. In April 1993, St. Louis Regional Medical Center established an on-demand labor epidural service. We obtained demographic data for all patients and reviewed the operative records of all patients undergoing cesarean section who delivered 12 mo before and 16 mo after the start of the labor epidural service. We compared labor epidural rates and total and nulliparous dystocia cesarean delivery rates before and after the epidural service started and among patients who did and did not receive labor epidural analgesia when it was available. Included were 3195 patients who delivered before and 3733 patients who delivered after epidural analgesia became available. Labor epidural rates were 1.2% vs 29.4% for the Before group versus the After group (P < 0.001). Total (9.1% vs 9.7%) and nulliparous dystocia (5.7% vs 6.4%) cesarean delivery rates did not significantly change with the availability of epidural analgesia. However, the total (11.6% vs 8.8%; P = 0.009) and dystocia (8.0% vs 1.0%; P = 0.001) cesarean delivery rates were higher among patients who received epidural analgesia when it was available. We conclude that epidural labor analgesia is associated with, but does not cause, cesarean delivery for dystocia. IMPLICATIONS: Increased epidural analgesia use did not change the overall dystocia cesarean delivery rate, although dystocia was more common among women who chose an epidural analgesia. Consequently, limiting epidural availability will not affect cesarean delivery rates. The evidence does not support advising patients that epidural labor analgesia increases the risk of cesarean delivery.

Effects of transdermal nicotine or smoking on nicotine concentrations and maternal-fetal hemodynamics.

OBJECTIVE: To compare nicotine concentrations and fetal middle cerebral artery resistance indices (RIs) during 21-mg transdermal nicotine use with these values during maternal smoking. METHODS: In this randomized, crossover study, participants smoked approximately 20 cigarettes daily and were between 24 and 36 weeks' gestation. Subjects were randomized to transdermal nicotine or to smoking ad libitum for 8 hours. One week later, they crossed over to the other condition. Maternal plasma nicotine concentrations and hemodynamic measurements were obtained before and after the onset of smoking or patch placement. RESULTS: Area under the plasma nicotine concentration-time curve during patch use was similar to continued smoking (93 versus 89 ng-hour/mL, respectively) (P = .77). The mean (standard error [SE] change in the middle cerebral artery RI from baseline to 4 hours later was similar during patch use and smoking: -.002 (0.008) versus -.02 (0.015), respectively (P = .3). The study had greater than 80% power to detect a 25% difference in nicotine concentrations and a change of 2 standard deviations in the middle cerebral artery RI between conditions. An unexpected finding was that of a loss of fetal heart rate (FHR) reactivity in 5/8 tracings after patch placement versus 1/6 tracings after smoking (P = .12). The baseline FHR increased by a mean (SE) of 8 (4) beats per minute with loss of reactivity in the patch condition, compared with a decrease of 3 (3) beats per minute without loss of reactivity (P = .05). CONCLUSION: Eight-hour use of 21-mg transdermal nicotine yields nicotine concentrations and middle cerebral artery RIs similar to those produced by hourly smoking in pregnant smokers.

Trisomy 16 mosaicism in amniotic fluid cell cultures.

Trisomy 16 mosaicism was found in amniotic fluid cells in a patient undergoing amniocentesis because of elevated second-trimester maternal serum alpha-fetoprotein (MSAFP) (2.80 MOM), a markedly elevated human chorionic gonadotropin level (hCG) (12.02 MOM), and a Down syndrome risk of 1:55. Ultrasound evaluation of the fetus indicated the presence of an atrial septal defect and clinodactyly. Cytogenetic analyses of various fetal tissues using fluorescence in situ hybridization (FISH) failed to detect substantial numbers of trisomy 16 cells; however, trisomy 16 mosaicism was identified in placental tissue. Molecular genetic analysis at five different loci [four analysed by polymerase chain reaction (PCR) and one by Southern blot analysis] failed to show any evidence for uniparental disomy. Although trisomy 16 cells could not be clearly demonstrated in the fetus, the presence of a clinically significant proportion of aneuploid cells early in development could not be excluded and it therefore cannot be assumed that a 'confined placental mosaicism' existed. The markedly elevated hCG and elevated MSAFP levels are consistent with abnormal placental function in trisomy 16 mosaicism. Serial ultrasound evaluation (to detect any late-onset growth retardation) and fetal echocardiography may be indicated for patients with extraordinarily high levels of hCG, especially if MSAFP is also elevated.

Prenatal diagnosis of intracranial lipoma associated with agenesis of the corpus callosum.

BACKGROUND: Lipoma of the corpus callosum is a congenital malformation present in 1:1700 individuals. Only three cases of prenatal sonographic diagnosis have been described. CASES: Two cases of prenatal sonographic diagnosis of intracranial lipoma are described. The first case was visible at 26 weeks' gestation and was associated with partial agenesis of the corpus callosum, a characteristic midline gyral pattern, and fetal colpocephaly. The second case was an isolated lipoma diagnosed at 37 weeks. In both cases transvaginal scanning and color Doppler studies were useful adjuncts in making the diagnosis. CONCLUSION: Prenatal sonographic diagnosis of intracranial lipoma associated with agenesis of the corpus callosum is possible as early as 26 weeks' gestation. Because prognosis depends on associated anomalies, a detailed examination of fetal intracranial anatomy and a complete anatomic survey should be performed. Awareness of this lesion can be expected to increase its detection on prenatal sonography.

Neurosonographic abnormalities associated with maternal history of cocaine use in neonates of appropriate size for their gestational age.

PURPOSE: To determine whether increased incidence of neurosonographic abnormalities (predominantly of the basal ganglia and thalamus) in cocaine-exposed neonates who are small for their gestational age is attributable to the cocaine or to neonatal size. METHODS: Neonates whose sizes were appropriate for their gestational age with no evidence of hypoxia or respiratory distress were identified prospectively by a maternal history of cocaine use. Scans were performed within 72 hours of birth using a 7.5-MHz transducer following a standard protocol. The images were analyzed without access to patient information. Forty study neonates were compared with 34 control subjects who were appropriate in size for their gestational age, scanned using the same protocol. Comparisons were made using Fisher Exact Test, t test, and logistic regression. RESULTS: No control infant had neurosonographic abnormalities. In the study group, gestational age ranged from 27 to 41 weeks. Of the 40 study neonates, 14 (35%) had one neurosonographic abnormality; two had two abnormalities. The predominant lesion was focal echolucencies, mainly in the area of the basal ganglia (10 of 40, 25%). Other findings were caudate echogenicity (3 of 40, 7.5%), ventricular dilation (2 of 40, 5%) and one "moth-eaten" appearance of the thalamus. Lesions were more likely approaching term and were not related to prematurity or alcohol use. CONCLUSION: Apparently normal neonates with a maternal history of cocaine use are likely to have degenerative changes or focal infarctions in their basal ganglia attributable to cocaine. Neurosonography should be used to evaluate these neonates. The long-term significance of these lesions needs further evaluation.

Neurosonographic imaging of small-for-gestational-age neonates exposed and not exposed to cocaine and cytomegalovirus.

We sought to prospectively identify the role of neurosonography in the evaluation of a consecutive group of small-for-gestational-age (SGA) neonates, and also to identify the association of neurosonographic findings with cocaine exposure and cytomegalovirus (CMV) infection. Neurosonographic imaging was performed in 180 SGA neonates within 72 hours of birth. Urine samples were screened for CMV and cocaine metabolites (CM) in all cases. Sixty-five neonates (37.5%) had an abnormal neurosonographic appearance. Nine neonates were positive for CMV and 31 neonates were positive for CM. Focal echolucencies (27), ventricular dilation (27), and subependymal hemorrhages (12) were the most common neurosonographic abnormalities. The first two were more common with CM (p < .05). An abnormal neurosonographic pattern was seen more often in SGA neonates with CM (54.8%, 17 of 31; p < .05) and CMV (67%, 6 of 9; p < .01) as compared with the rest (32.6%, 44 of 135; p < .01). Among those without CM or CMV, prematurity was associated with an increased risk for abnormality (p < .001 between groups), specifically subependymal hemorrhage, ventricular dilation, and porencephalic cysts. Five CMV-positive neonates showed periventricular, echogenic foci mainly in the area of the frontal horn. Two new findings with SGA were caudate nucleus echogenicity and a "moth-eaten" appearance of the thalamus, each found in three infants. Neurosonographic imaging is useful in the evaluation of SGA neonates. Focal echolucencies and caudate echogenicity suggest maternal cocaine use, and periventricular echogenic foci strongly suggest fetal CMV infection.

Relationship of measured external tocodynamometry with measured internal uterine activity.

The use of home uterine activity monitoring for patients at high risk for preterm labor and delivery has become common in clinical perinatology. The ability of the monitoring devices to detect accurately uterine contractions in early pregnancy has not previously been reported. Ten women in labor between 20 and 35 weeks' gestation underwent simultaneous monitoring of uterine activity with a guard-ring tocodynamometer and an intrauterine pressure monitor. When compared with internal monitoring, the external monitor detected 90.8% of uterine contractions with a specificity for uterine quiescence of 98.1%. The predictive value of external monitoring was 97.3% for detecting uterine contractions and 93.6% for recording the absence of uterine contractions. The contractions detected externally were similar in duration: mean 63.7 +/- 23.0 seconds for internal monitoring and 62.2 +/- 22.6 seconds for external monitoring (p greater than 0.05). The intensity of contractions detected externally was less than internally measured contractions, mean difference, 19.7 +/- 15.9 mmHg (p less than 0.001). External tocodynamometry using this guarding tocodynamometer reliably distinguishes between uterine contractions and uterine quiescence in preterm pregnancies but does not adequately measure the intensity of contractions.

Human figure drawings of adjudicated and nonadjudicated adolescents.

We investigated differences between human figure drawings of adjudicated and nonadjudicated adolescents. In addition, the relationship between human figure drawings and crime category (person, property, other, none) was examined for the adjudicated adolescents. Subjects consisted of four groups of adolescents (n = 25 each): adjudicated males, adjudicated females, nonadjudicated males, and nonadjudicated females. Human figure drawings were obtained from all subjects; they were scored using a system that was developed for use with adolescents. Kruskal-Wallis one-way analyses of variance (ANOVAs) were used to assess the effects of adjudication status and gender. There were 11 significant differences between adjudicated and nonadjudicated adolescents and 11 differences among the four groups. Results of Kruskal-Wallis ANOVAs also showed two significant differences among crime categories.

Cervical effacement: variation in belief among clinicians.

Cervical effacement may be described as a percentage or as residual cervical length in centimeters. For effective communication among clinicians, the percentage method requires agreement about the length of the uneffaced cervix. Variation in beliefs regarding cervical effacement and length was assessed among practicing obstetricians at a single medical center. The mean estimate for the length of the uneffaced cervix at term was 2.47 +/- 0.64 cm, with a range of 1-4 cm and a coefficient of variation of 26%. The mean estimate of physicians in private practice was significantly shorter (P less than .001) than that of faculty and house staff combined. There is the potential for miscommunication among physicians based on variation in beliefs about effacement. Adoption of the metric system for description of the cervix would eliminate hidden assumptions about cervical length and the concept of effacement.

A comparison of the effect of epidural, general, and no anesthesia on funic acid-base values by stage of labor and type of delivery.

The effect of epidural anesthesia on neonatal acid-base status, before, during, and after labor, was determined by review of funic blood-gas values from 142 women with normal term pregnancies and normal fetal heart rate patterns. Funic acid-base parameters were compared by type of anesthesia when stratified by mode of delivery (vaginal, cesarean section in the active phase of labor, or elective cesarean section). Use of epidural analgesia for vaginal delivery was associated with significantly longer labor, lower umbilical arterial pH, higher arterial PCO2 and arterial bicarbonate values. In women who had cesarean section in the active phase of labor, use of epidural anesthesia was associated with significantly lower arterial and venous PO2 values when compared with women who received general anesthesia. Patients who had elective cesarean section with epidural anesthesia had funic acid-base values similar to women who had general anesthesia. Epidural analgesia-anesthesia offers no clear advantage to the uncompromised term fetus.

Transabdominal and transvaginal ultrasonography in the diagnosis of ectopic pregnancy: a comparative study.

Thirty-four patients believed to have ectopic pregnancies were examined by transabdominal and transvaginal ultrasonography. Twenty-five patients had tubal pregnancy confirmed operatively within 24 hours after ultrasonographic examination. In these cases adnexal findings highly suspicious for ectopic pregnancy were found in 68% of cases by transabdominal ultrasonography and in 84% by transvaginal ultrasonography. A distinct adnexal gestational sac was apparent in 32% of cases by transabdominal ultrasonography and in 64% of cases by transvaginal ultrasonography. Transvaginal ultrasonography was significantly more accurate (p less than 0.01) in identifying an adnexal gestational sac and allows more detailed adnexal imaging.

Prenatal detection of non-cardiac rhabdomyosarcoma.

The most prevalent soft tissue tumour in children is rhabdomyosarcoma. These tumours may develop within or outside of muscle anywhere in the body and at any age. We report what is apparently the earliest case of non-cardiac rhabdomyosarcoma detected prenatally.

Spironolactone and estrogen-progestin therapy for hirsutism.

Sixteen women with hirsutism used spironolactone, 100 mg daily without interruption, plus norethindrone (1 mg) and ethinyl estradiol (35 mg) for 21 of each 28 days. Clinical improvement occurred in 11 of the 16 patients and also in an additional patient when the dose of spironolactone was increased to 200 mg daily. Spironolactone 100 mg daily plus norethindrone and ethinyl estradiol resulted in significant reduction in serum total testosterone, serum free testosterone, and percentage of free testosterone. Side effects were infrequent.