The operational window of carbon nanotube electrical wires treated with strong acids and oxidants.

Conventional metal wires suffer from a significant degradation or complete failure in their electrical performance, when subjected to harsh oxidizing environments, however wires constructed from Carbon Nanotubes (CNTs) have been found to actually improve in their electrical performance when subjected to these environments. These opposing reactions may provide new and interesting applications for CNT wires. Yet, before attempting to move to any real-world harsh environment applications, for the CNT wires, it is essential that this area of their operation be thoroughly examined. To investigate this, CNT wires were treated with multiple combinations of the strongest acids and halogens. The wires were then subjected to conductivity measurements, current carrying capacity tests, as well as Raman, microscopy and thermogravimetric analysis to enable the identification of both the limits of oxidative conductivity boosting and the onset of physical damage to the wires. These experiments have led to two main conclusions. Firstly, that CNT wires may operate effectively in harsh oxidizing environments where metal wires would easily fail and secondly, that the highest conductivity increase of the CNT wires can be achieved through a process of annealing, acetone and HCl purification followed by either H2O2 and HClO4 or Br2 treatment.

OS087. Maternal characteristics, mean arterial pressure and PLGF in early prediction of preeclampsia.

INTRODUCTION: In a previous study, we described the predictive value of first-trimester pregnancy-associated plasma protein-A (PAPP-A), free beta-subunit of human chorionic gonadotrophin (fb-hCG), Placental Growth Factor (PlGF) and A Desintegrin And Metalloproteinase 12 (ADAM12) for early onset preeclampsia (delivery <34 weeks) [1]. OBJECTIVES: The objective of the current study was to obtain the predictive value of these serum makers, for both early onset PE (EOPE) and late onset PE (LOPE), combined with maternal characteristics and first-trimester maternal mean arterial blood pressure (MAP). METHODS: This was a nested case-control study, using stored first-trimester maternal serum from 167 women who subsequently developed PE, and 500 uncomplicated singleton pregnancies which resulted in a live birth =>37 weeks. Maternal characteristics (i.e. medical records, parity, weight, length) MAP and pregnancy outcome (i.e. gestational age at delivery, birthweight, fetal sex) were collected for each individual and used to calculate prior risks for PE in a multiple logistic regression model. MAP values and marker levels of PAPP-A, fb-hCG, PlGF and ADAM12 were expressed as multiples of the gestation-specific normal median (MoMs). Subsequently, MoMs were log-transformed and compared between PE and controls using Student's t-tests. Posterior risks were calculated using different combinations of variables;(1) maternal characteristics, serum markers, and MAP separately (2) maternal characteristics combined with serum markers or MAP (3) maternal characteristics combined with serum markers and MAP. The model-predicted detection rates (DR) for fixed 10% false-positive rates were obtained for EOPE and LOPE with or without intra-uterine growth restriction (IUGR,birth weight <10th centile). RESULTS: The maternal characteristics: maternal age, weight, length, smoking status and nulliparity were discriminative between PE and control groups and therefore incorporated in the multiple logistic regression model. MoM MAP was significantly elevated (1.10 p<0.001; 1.07 p<0.001) and MoM PlGF was significantly reduced (0.95 p=0.016; 0.90 p=0.029) in the EOPE and LOPE group, respectively. The differences in markers for IUGR groups were larger. The estimated DRs of the three different models are presented in the table. CONCLUSION: This study demonstrates that first-trimester MAP and PlGF combined with maternal characteristics are promising markers in risk assessment for PE. Combination of markers proved especially useful for risk assessment for term PE. Detection rates were higher in the presence of IUGR.

Longitudinal trends in fetoplacental biochemical markers, uterine artery pulsatility index and maternal blood pressure during the first trimester of pregnancy.

OBJECTIVE: To assess trends in levels of biochemical markers, uterine artery (UtA) pulsatility index (PI) and maternal blood pressure changes over time and study their relationships in uncomplicated first-trimester pregnancies. METHODS: The study population comprised 86 women with singleton pregnancies. In each woman, a blood sample was collected at 6-7, 8-9, 10-11 and 12-13 weeks' gestation. At the same visit blood pressure was measured and ultrasound examination was performed to measure the crown-rump length and Doppler flow velocity waveform patterns of both UtAs. Serum concentrations of pregnancy-associated plasma protein-A (PAPP-A), free ß-human chorionic gonadotropin (ß-hCG), A disintegrin and metalloprotease domain-containing protein-12 (ADAM-12), placental protein-13 (PP-13) and placental growth factor (PlGF) levels were measured in thawed specimens using an automated time-resolved fluorescence assay. Summary curves were created to describe normal ranges and trends over time. The data were analyzed with a linear mixed model with the log-transformed marker values as dependent variables. This allowed for flexible modeling of patterns over time. RESULTS: Sixty-eight pregnancies had an uneventful outcome, with the birth of an appropriate-for-gestational-age (AGA) infant. In these pregnancies serum PAPP-A, ADAM-12, PP-13 and PlGF levels increased with gestational age. The UtA-PI decreased and the mean arterial blood pressure remained constant. There were no significant correlations between maternal age, birth-weight percentile, gender and blood pressure and any of the biochemical markers. The serum markers were highly correlated with each other except for ß-hCG. A negative correlation was found between most biomarkers and UtA-PI, especially from 10 weeks onwards. Serum concentrations of ADAM-12 and PP-13 were lower in a small-for-gestational-age (SGA) subgroup born at term (n = 6), the former statistically significantly (P = 0.031), the latter non-significantly (P = 0.054), whereas UtA-PI was significantly higher (P = 0.02). Biomarker concentrations in 12 women delivering a large-for-gestational age infant did not differ from those delivering AGA neonates. CONCLUSION: There is a relationship between biochemical markers of early placentation and downstream resistance to flow in the UtAs in low-risk uncomplicated pregnancies, indicating differences in placentation. In a small series of SGA infants born at term we could demonstrate differences as compared to normal pregnancies, with potential value for screening.

Prediction of macrosomia at birth in type-1 and 2 diabetic pregnancies with biomarkers of early placentation.

OBJECTIVE: To evaluate the value of first trimester placental biomarkers (fß-hCG, PAPP-A, ADAM12, PP13 and PlGF) and fetal nuchal translucency (NT) in the prediction of macrosomia at birth in pregestational type-1 and type-2 diabetes (PGDM). DESIGN: Nested case-control study. SETTING: Routine first-trimester combined test. POPULATION: A total of 178 PGDM and 186 control pregnancies. METHODS: ADAM12, PP13 and PlGF concentrations were measured in stored first-trimester serum, previously tested for fß-hCG and PAPP-A. All concentrations were expressed as multiples of the median (MoM). Where applicable, the median MoMs of PGDM and control pregnancies were compared in relation to birthweight centiles (≤90th centile, non-macrosomic, versus >90th centile, macrosomic). Model-predicted detection rates for fixed false-positive rates were obtained for statistically significant markers, separately and in combination. MAIN OUTCOME MEASURES: Prediction of macrosomia in diabetic pregnancies. RESULTS: In the PGDM group, median ADAM12 MoM (0.88; P = 0.007) was lower than in the controls. Subgroup analyses showed that median MoMs of PAPP-A (0.65), ADAM12 (0.85), PP13 (0.81) and PlGF (0.91) were only reduced in the PGDM non-macrosomic birthweight subgroup (n = 93) compared with other weight subgroups. In the PGDM macrosomic birthweight subgroup (n = 69), MoMs of all markers were comparable with the control birthweight subgroups. The screening performance for macrosomia at birth in the PGDM group provided a detection rate of 30% for a 5% false-positive rate (FPR) and 43% for a 10% FPR. CONCLUSIONS: Macrosomia at birth in PGDM pregnancies may be predicted by normal levels of PAPP-A, ADAM12, PP13 and PlGF already in the first trimester of pregnancy. Fetal birthweight in PGDM offspring is partially determined by placental development during the first trimester of pregnancy. The present increase in fetal macrosomia may be related to better early glycemic control and placentation.

Interaction of topiramate with carbamazepine: two case reports and a review of clinical experience.

We describe a possible clinical interaction between topiramate (TPM) and carbamazepine modified release (CBZ-MR) in patients taking maximum tolerated doses of carbamazepine. Data are presented on 25 patients who contacted the epilepsy nurse specialist telephone helpline for advice after starting treatment with TPM. Thirteen male and 12 female patients, mean age 41 years (range 25-69 years), with localization-related epilepsy contacted the helplines, between November 1999 and March 2001, complaining of symptoms of antiepileptic drug intoxication after starting treatment with TPM. All were taking maximum tolerated doses of CBZ-MR before starting TPM. Sixteen of the patients were taking other antiepileptic drugs concomitantly with CBZ-MR and TPM. Symptoms of intoxication were similar to those previously experienced when maximum tolerated doses of CBZ-MR were exceeded. Symptoms resolved when concomitant CBZ-MR doses were reduced, enabling further dose escalation of TPM. To our knowledge, neither clinical nor pharmacological interactions between CBZ and TPM have been described previously in man. These data suggest that such an interaction may be of clinical importance, and that reduction of the CBZ dose may enable optimization of the dose of TPM, improving seizure control.