Opportunities of waste heat recovery from various sources: Review of technologies and implementation.

Waste heat recovery (WHR) using conventional technologies can provide appreciable amounts of useful energy from waste heat (WH) sources, thus reducing the overall energy consumption of systems for economic purposes, as well as ameliorating the impact of fossil fuel-based CO2 emissions on the environment. In the literature survey, WHR technologies and techniques, classifications and applications are considered and adequately discussed. The barriers affecting the development and utilization of systems of WHR, as well as possible solutions are presented. Available techniques of WHR are also discussed extensively, with a particular interest in their progressive improvements, prospects, and challenges. The economic viability of various WHR techniques is also taken into account considering their payback period (PBP), especially in the food industry. A novel research area wherein the recovered WH of flue gases from heavy-duty electric generators was utilized for agro-products drying has been identified, which may be useful in the agro-food processing industries. Furthermore, an in-depth discussion on the appropriateness and applicability of WHR technology in the maritime sector is given a prominent touch. In many review works involving WHR, different areas such as WHR sources, methods, technologies, or applications were discussed, albeit not in a comprehensive way touching on all-important aspects of this branch of knowledge. However, in this paper, a more holistic approach is followed. Furthermore, many recently published articles in different areas of WHR have been carefully examined and the recent findings provided are presented in this work. The recovery of waste energy and its utilization is capable of significantly dropping the level of production costs in the industrial sector and harmful emissions to the environment. Some of the benefits derivable from the application of WHR in the industries may include a reduction in energy, capital, and operating costs, which translate to reduced cost of finished products, and the mitigation of environmental degradation through the reduction of the emission of air pollutants and greenhouse gases. Future perspectives on the development and implementation of WHR technologies are presented in the conclusions section.

A successful pregnancy in a Turner syndrome with oocyte donation.

Advances in reproductive medicine using oocyte donation have made it possible for women with Turner syndrome (TS) to achieve successful pregnancies. These pregnancies carry substantial fetal and maternal risks, with hypertensive disorders or pregnancy and fetal growth restriction common, and an increased risk of aortic dissection, sometimes fatal, for the woman. Careful prepregnancy assessment and fetal and maternal vigilance during pregnancy is a necessary prerequisite for a successful outcome. We present a case of a woman with Turner syndrome achieving a successful pregnancy from donor oocyte and review the relevant literature.

Mercuric ion inhibition of eukaryotic transcription factor binding to DNA.

Mercury has harmful effects in both rodents and humans. In rodent tissue culture cells exposed to HgCl(2), the metal ions were observed to concentrate in cell nuclei and to associate with chromatin. Thus, transcription factors and other proteins associated with chromatin are possible targets of mercuric ion toxicity. In this study, mercuric ions were found to inhibit the DNA binding activity of the Cys(2)His(2) zinc finger proteins transcription factor IIIA (TFIIIA) and Sp1. These factors are prototypes of the largest eukaryotic protein superfamily. Neither the presence of excess zinc ions nor beta-mercaptoethanol prevented inhibition by mercuric ions. Mercuric ions also inhibited DNA binding by the non-zinc finger protein AP2. Zinc finger-DNA binding was inhibited when both TFIIIA/5S RNA complex and TFIIIA alone were preincubated with concentrations as low as 15 microM mercuric ion. Inhibition occurred in less than 1 min and was not readily reversible. Mercuric ions also inhibited the digestion of DNA by the restriction enzymes BamHI or EcoRI. Inhibition of transcription factors as well as potentially other DNA binding proteins by micromolar concentrations of mercuric ion suggests additional biochemical mechanisms for mercury toxicity in promoting disease via alterations in gene transcription patterns.

Rupture of pregnancy in the communicating rudimentary uterine horn at 34 weeks.

Pregnancy in the rudimentary horn is rare and represents a form of ectopic gestation. Despite advances in ultrasound, prenatal diagnosis remains elusive, with confirmatory diagnosis being made at laparotomy. Because of variable muscular constitution of the wall of the rudimentary horn, pregnancy can be accommodated until late in pregnancy, when rupture occurs manifesting commonly as acute abdomen with high risk of maternal mortality. The rudimentary horn may or may not communicate with the uterine cavity with majority of cases being non-communicating. We present a case of pregnancy in the communicating horn that was difficult to diagnose which ruptured at 34 weeks and a review of literature.

The fetal outcome in pregnancies with isolated reduced amniotic fluid volume in the third trimester.

Our aim was to assess the outcome of pregnancies where oligohydramnios, defined by a published gestational reference range for amniotic fluid index, was the only abnormal finding at third trimester scan, and all other ultrasound parameters including biometry were within normal limits at initial scan. A retrospective case-control study was performed at The Liverpool Maternity Hospital. 103 pregnancies with reduced amniotic fluid index in the third trimester and apparently normal fetal growth profile ultrasonographically were identified from ultrasound reports throughout 1993. Pregnancies in the third trimester with normal amniotic fluid index on index scan were also identified from these reports and 103 were matched for parity, gestational age at delivery, mode of onset of labour, presentation at labour and medical conditions. Exclusion criteria were ruptured membranes, fetal abnormalities, estimated fetal weight below the fifth centile at index scan and multiple pregnancies. The outcome criteria were birthweight, Apgar scores at delivery, induction and emergency delivery for fetal reasons and admission to Neonatal Intensive Care Unit. Statistical analysis was performed by Fisher's exact test and Gart's odds ratio. Compared with controls, pregnancies in the reduced liquor group had a higher number of babies below the 5th centile (odds ratio 5.2, 95% confidence interval 1.6 to 22), a higher risk of induction for fetal reasons (odds ratio 34.4, 95% confidence interval 5.35 to 1425.5) and admission to Neonatal Intensive Care Unit (odds ratio 9.77, 95% confidence interval 1.3 to 432). Any observed difference in the need for emergency delivery due to fetal reasons was not clinically significant (odds ratio 2.16, 95% confidence interval 0.77 to 6.6) The definition used for oligohydramnios used in this study appears to identify a group of babies with a fourfold risk of low birthweight and a high risk of admission to the Neonatal Intensive Care Unit and induction of labour for fetal reasons. This would suggest that pregnancies with isolated oligohydramnios require some form of fetal monitoring and further prospective studies are required to determine the most appropriate method.

Outcome of ruptured uterus at University Teaching Hospital Aleppo, Syria.

A 10-year review of ruptured gravid uterus at the University Teaching Hospital, Aleppo, Syria showed an incidence of one ruptured uterus in 565 deliveries. This is an average figure compared with published studies but is still high compared with developed countries. Sixty-four per cent of the cases of ruptured uterus had no antenatal care. It is no surprise therefore that maternal and fetal mortality was highest amongst the unbooked labouring women. In survivors the morbidity was also higher. Ruptured uterus is therefore a major cause of maternal and perinatal mortality and morbidity in Syria. The overall hospital maternal and perinatal mortalities for the period under review were 4.3% and 2.6% respectively. The main risk factor identified is scarring from previous caesarean sections. Other risk factors are discussed.

Longitudinal assessment of amniotic fluid index.

OBJECTIVE: To derive a longitudinal gestational reference range for amniotic fluid index and to compare it with the established cross-sectional reference range. DESIGN: Longitudinal prospective study. SETTING: Liverpool Maternity Hospital and Mill Road Maternity Hospital, both teaching hospitals in central Liverpool. SUBJECTS: One hundred and fifteen pregnant women, in whom the expected date by the last menstrual period and ultrasound scan at 18 to 19 weeks were in agreement by seven days, were recruited. They were divided into two groups and scanned at four weekly intervals as follows: Group A: scanned at 20, 24, 28, 32, 36, 40; and Group B: scanned at 22, 26, 30, 34, 38, 42. RESULTS: Amniotic fluid index varies with gestation, rising from early gestation to peak at 30 weeks and then falling from 36 to 42 weeks. Comparison of our reference range with that of Moore and Cayle (1990) shows obvious differences at the lower limit. CONCLUSION: We have established a normal longitudinal reference range for the amniotic fluid index. Our ranges, derived from longitudinal data, would seem a more appropriate reference than the established reference ranges derived from cross-sectional data. In particular, the differences at the lower limits may have considerable clinical implication in the use of amniotic fluid index in the prediction of fetal compromise.

Partial hydatidiform mole and hypertension associated with a live fetus--variable presentation in two cases.

Partial hydatidiform mole associated with live births is a rare condition. There are not enough cases in the literature to allow the assessment of comprehensive risks to be made and upon which management policies can be based. Several clinical dilemmas arise following diagnosis of a viable pregnancy associated with molar tissue. We present two cases demonstrating the problems and suggest management based on outcome and a review of the literature.

A case of severe diabetic retinopathy in pregnancy.

Proliferative retinopathy is a recognized long-term complication of diabetes and the commonest cause of blindness in young people. There is, however, some uncertainty regarding counselling given on the continuation of pregnancy when it is complicated by retinopathy. This case is used to highlight this difficulty and to discuss management based on literature review.

Undiagnosed breech.

OBJECTIVES: To assess the proportion of breech presentations diagnosed in labour and to compare their outcomes with those diagnosed prior to the onset of labour. DESIGN: Retrospective casenote review. SETTING: Mill Road Maternity Hospital, a teaching hospital in central Liverpool. SUBJECTS: Three hundred and five singleton breech presentations delivered in the hospital between January 1988 and July 1991; 226 cases prior to the onset of labour and 79 cases diagnosed for the first time in labour. MAIN OUTCOME MEASURES: Rates of vaginal delivery and caesarean section, birthweight, short term morbidity as assessed by trauma, signs of cerebral irritation and admission to the newborn intensive care unit (NBICU), and Apgar scores. RESULTS: Breech presentations diagnosed for the first time in labour were more likely to deliver vaginally than those assessed and allowed to go into labour (odds ratio 1:68 95% CI 1.0-3.0). This difference was not due to demographic variables or differences in birthweight. There was no short term morbidity attributable to vaginal breech delivery. CONCLUSION: A significant number of breech presentations are not detected until labour despite rigorous antenatal surveillance. Our results show that undiagnosed breeches may not be important as they are more likely to deliver vaginally, with no excess morbidity or mortality, compared to diagnosed breeches in labour, carefully assessed for vaginal delivery. There are, therefore, no grounds for delivering all undiagnosed breeches by caesarean section.

Is fetal gender significant in the perinatal outcome of pregnancies complicated by placental abruption?

Seventy cases of placental abruption were studied. These occurred in 12,800 deliveries, an incidence of 4.8 per 1000. There were more female infants (34-56%) compared with males (27-44%). Sixteen infants were stillborn and one baby died in the neonatal period. Thirteen of the perinatal deaths occurred in male infants. We speculate that a higher metabolic rate in male infants may account for this sex difference.