Dry turning of alumina/aluminum composites with CVD diamond coated Co-cemented tungsten carbide tools

Triangular (TPGN 160308) WC-6 wt.%Co inserts having different average grain sizes (1 and 3 µm) were submitted to surface roughening either by wet etching with Murakami's reagent or by a heat treatment in the hot filament chemical vapour deposition (HFCVD) reactor. The heat treatment was performed in a monohydrogen-rich atmosphere at substrate temperatures as high as 1000 degrees C. Scanning electron microscopy and energy-dispersive spectroscopy showed that this pre-treatment led to surface roughening of the as-ground inserts and to a lower surface Co concentration. Prior to deposition, all inserts were etched with an acid solution of hydrogen peroxide. Diamond coatings were deposited by HFCVD. The coated inserts were tested by dry machining of aluminum-matrix composite (Al-10%Al2O3) bars. Turning test results indicated that a proper combination of substrate pretreatment and microstructure can significantly improve tool life

Fetuses with right aortic arch Multicentre cohort study and meta-analysis.

OBJECTIVES: Recent antenatal screening guidelines for cardiac abnormalities has increased fetal diagnosis of right aortic arch (RAA). We aimed to establish outcome of fetal RAA without intra-cardiac abnormalities (ICA) to guide postnatal management. METHODOLOGY: Retrospective cohort study. Outcome measures were rates of chromosomal abnormalities, 22q11.2 deletion, fetal extra-cardiac abnormalities (ECA), postnatal ICA and ECA, symptoms and surgery for vascular ring. A systematic review and meta-analysis (reference: CRD42015016097) was performed; results are reported as proportions. Kaplan Meier analysis of vascular ring cases with surgery as endpoint was performed. RESULTS: Our cohort included 86 cases; 41 had a vascular ring. Rates of chromosomal abnormalities, 22q11.2 deletion, and fetal ECA were 14.1%, 6.4% and 17.4% respectively. Sixteen studies including our cohort (312 fetuses) were included in the systematic review. Overall chromosomal abnormalities and 22q11.2 deletion rates were 9.0% (95% CI 6.0-12.5) and 6.1% (95% CI 3.6-9.3) whilst rates for cases with no ECA were 4.6% (95% CI 2.3-7.8) and 5.1% (95% CI 2.4-8.6). ECA were seen in 14.6% (95% CI 10.6-19.0) prenatally and 4.0% (95%CI 1.5-7.6) after birth. Postnatal ICA were identified in 5.0% (95% CI 2.7-7.9). Rate of symptoms (follow up ≥24 months) was 25.2% (95% CI 16.6-35.0) while 17.1% (95% CI 9.9-25.7) had surgery. Two-year freedom from surgery was 83.0% (95% CI 74.3-90.1) CONCLUSIONS: Fetal RAA without ICA is more frequently associated with ECA than chromosomal abnormalities. Most cases however, are isolated. Vascular ring symptoms occur in about 25% of cases. Postnatal surveillance is required mainly in the first 2 years of life

Fetal midline anomalies: Diagnosis and counselling Part 1: Corpus callosum anomalies.

Midline anomalies encompasses a heterogeneous group of conditions caused by an abnormal process of ventral induction after the end of primary neurulation. Advances in prenatal imaging techniques have led to an increase in the detection rate of such anomalies since the first trimester of pregnancy although a significant proportion of them remain undiagnosed until birth. Ultrasound is the primary technique in detecting such anomalies while fetal magnetic resonance imaging (MRI) is commonly performed to confirm the diagnosis and detect additional anomalies, especially those involving the cortical surface of the brain, which may potentially impact post-natal outcome. Neurodevelopmental outcome of cerebral anomalies involving the midline is directly related to the type of anomaly, cause and presence of associated anomalies. However, even in case of isolated anomalies prenatal counselling is challenging. The aim of this review is to provide an up to date on the diagnosis, counselling and management of the most common supra-tentorial anomalies involving the midline and diagnosed on prenatal ultrasound

Patterns of Second- and Third-Trimester Growth and Discordance in Twin Pregnancy: Analysis of the Southwest Thames Obstetric Research Collaborative (STORK) Multiple Pregnancy Cohort.

INTRODUCTION: This study investigates patterns of intertwin size discordance in dichorionic diamniotic (DCDA) and monochorionic diamniotic (MCDA) twin pregnancies. MATERIAL AND METHODS: Ultrasound measurements of twin pregnancies, from 14 weeks to term, were collected by 9 hospitals over a 10-year period. This analysis considers the modelled and observed levels of discordance in abdominal circumference (AC) and estimated fetal weight (EFW) in relation to gestational age. Fitted models were analysed to produce charts displaying the expected range of intertwin discordance in AC and EFW at any given examination. RESULTS: The dataset for analysis included a total of 9,866 ultrasound examinations in 1,802 DCDA and 323 MCDA twin pregnancies. The 95th percentile of intertwin discordance in EFW increased from 18.3% (95% CI, 17.8-18.7%) at 20 weeks to 21.9% (95% CI, 21.3-22.4%) at 30 weeks for DCDA pregnancies. The 95th percentile for intertwin discordance in AC was stable at 10-11% for this period. Slightly higher levels of discordance were observed for MCDA than for DCDA pregnancies. DISCUSSION: The expected range of intertwin discordance in EFW and AC shows differences with gestational age and between DCDA and MCDA pregnancies