Thin-Film Composite Membranes for Hydrogen Evolution with a Saline Catholyte Water Feed

Hydrogen gas evolution using an impure or saline water feed is a promising strategy to reduce overall energy consumption and investment costs for on-site, large-scale production using renewable energy sources. The chlorine evolution reaction is one of the biggest concerns in hydrogen evolution with impure water feeds. The "alkaline design criterion" in impure water electrolysis was examined here because water oxidation catalysts can exhibit a larger kinetic overpotential without interfering chlorine chemistry under alkaline conditions. Here, we demonstrated that relatively inexpensive thin-film composite (TFC) membranes, currently used for high-pressure reverse osmosis (RO) desalination applications, can have much higher rejection of Cl- (total crossover of 2.9 ± 0.9 mmol) than an anion-exchange membrane (AEM) (51.8 ± 2.3 mmol) with electrolytes of 0.5 M KOH for the anolyte and 0.5 M NaCl for the catholyte with a constant current (100 mA/cm2 for 20 h). The membrane resistances, which were similar for the TFC membrane and the AEM based on electrochemical impedance spectroscopy (EIS) and Ohm's law methods, could be further reduced by increasing the electrolyte concentration or removal of the structural polyester supporting layer (TFC-no PET). TFC membranes could enable pressurized gas production, as this membrane was demonstrated to be mechanically stable with no change in permeate flux at 35 bar. These results show that TFC membranes provide a novel pathway for producing green hydrogen with a saline water feed at elevated pressures compared to systems using AEMs or porous diaphragms.

A Review of Potential Electrochemical Applications in Buildings for Energy Capture and Storage

The integration of distributed renewable energy technologies (such as building-integrated photovoltaics (BIPV)) into buildings, especially in space-constrained urban areas, offers sustainable energy and helps offset fossil-fuel-related carbon emissions. However, the intermittent nature of these distributed renewable energy sources can negatively impact the larger power grids. Efficient onsite energy storage solutions capable of providing energy continuously can address this challenge. Traditional large-scale energy storage methods like pumped hydro and compressed air energy have limitations due to geography and the need for significant space to be economically viable. In contrast, electrochemical storage methods like batteries offer more space-efficient options, making them well suited for urban contexts. This literature review aims to explore potential substitutes for batteries in the context of solar energy. This review article presents insights and case studies on the integration of electrochemical energy harvesting and storage into buildings. The seamless integration can provide a space-efficient source of renewable energy for new buildings or existing structures that often have limited physical space for retrofitting. This work offers a comprehensive examination of existing research by reviewing the strengths and drawbacks of various technologies for electrochemical energy harvesting and storage, identifying those with the potential to integrate into building skins, and highlighting areas for future research and development.

Computational Quantum Chemistry Insights into the Mechanism of VO2 + Reduction on Graphene-Based Electrodes

The identity of active sites for redox reactions within vanadium redox flow batteries (VRFBs) isstill controversial despite decades of research into the matter. Here, we use density functional theory to examine the premise of selected surface functional groups as active sites and provide mechanistic insights into the reaction pathway for the positive electrode reaction. The adsorption of electroactive species on phenol and carbene-like edge carbon sites was compared using model aromatic clusters. Phenol groups were not favorable sites for the chemisorption of VO2 + in either V-down or O-down approach In contrast, carbene-like edge carbon sites readily adsorbed VO2 + via an oxygen-down approach, mimicking gas-phase CO2 adsorption mechanisms. Subsequent steps to complete the reaction pathway are a series of proton adsorptions and reaction products desorption. The rate-determining step for a reaction pathway using an edge site is VO2+ desorption step with a Gibbs energy of activation of +84 kcal mol-1 .

Thermodynamic and Kinetic Analyses of Ion Intercalation/Deintercalation Using Different Temperatures on NiHCF Electrodes for Battery Electrode Deionization

Prussian blue analogues are used in electrochemical deionization due to their cation sorption capabilities and ion selectivity properties. Elucidating the fundamental mechanisms underlying intercalation/deintercalation is important for the development of ion-selective electrodes. We examined the thermodynamic and kinetic properties of nickel hexacyanoferrate electrodes by studying different temperatures effects on intercalation/deintercalation with monovalent ions (Li⁺, Na⁺, K⁺, and NH₄⁺) relevant to battery electrode deionization applications. Higher temperatures reduced the interfacial charge transfer resistance and increased the diffusion coefficient of cations in the solid material. Ion transport in the solid material, rather than interfacial charge transfer, was found to be the rate-controlling step, as shown by higher activation energies for ion transport (e.g., 31 ± 3 kJ/mol for K⁺) than for interfacial charge transfer (5 ± 1 kJ/mol for K⁺). The largest increase in cation adsorption capacity with temperature was observed for NH₄⁺ (28.1% from 15 to 75 °C) due to its smallest activation energy. These results indicate that ion hydration energy determines the intercalation potential and activation energies of ion transport in solid material control intercalation/deintercalation rate. Together with the endothermic behavior of deintercalation and exothermic behavior of intercalation, the higher operating temperature results in improvement of ion adsorption capacity depending on specific cations.

Reimagining Rural: Shifting Paradigms About Health and Well-Being in the Rural United States

Rural health disparities have attracted increased national attention, compelling an expanded focus on rural health research. In this manuscript, we deconstruct the definitions and narratives of "rural" communities and suggest that a paradigm shift is needed that centers the complexity and strength of rural places. We discuss the relevance of health equity frameworks, implementation science, and community-engaged approaches to promote rural well-being. Focusing on rural in its own right will lead to intervention innovations and reinvention with implications beyond rural areas. We conclude with suggestions for research and practice to inspire renewed interest in partnering with rural communities to promote health equity. Expected final online publication date for the Annual Review of Public Health, Volume 43 is April 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Influence of Hydrotropes on the Solubilities and Diffusivities of Redox-Active Organic Compounds for Aqueous Flow Batteries

In this study, we explored the extent to which hydrotropes can be used to increase the aqueous solubilities of redox-active compounds previously used in flow batteries. We measured how five hydrotropes influenced the solubilities of five redox-active compounds already soluble in aqueous electrolytes (≥0.5 M). The solubilities of the compounds varied as a function of hydrotrope type and concentration, with larger solubility changes observed at higher hydrotrope concentrations. 4-OH-TEMPO underwent the largest solubility increase (1.18 ± 0.04 to 1.99 ± 0.12 M) in 20 weight percent sodium xylene sulfonate. The presence of a hydrotrope in solution decreased the diffusion coefficients of 4-OH-TEMPO and 4,5-dihydroxy-1,3-benzenedisulfonate, which was likely due to the increased solution viscosity as opposed to a specific hydrotrope-solute interaction because the hydrotropes did not alter their molecules' hydraulic radii. The standard rate constants and formal potentials of both 4-OH-TEMPO and 4,5-dihydroxy-1,3-benzenedisulfonate remained largely unchanged in the presence of a hydrotrope. The results suggest that using hydrotropes may be a feasible strategy for increasing the solubilities of redox-active compounds in aqueous flow batteries without substantially altering their electrochemical properties.

Electrochemical impedance spectroscopy and finite element analysis modeling of a 4-electrode humidity sensor for natural gas transportation pipelines

Reliable corrosion monitoring of natural gas transmission lines is a major tool providing a foundation for safe management of natural gas infrastructures. Through the development of membrane-based electrochemical sensors which are able to function in low-conductivity gas environments, corrosion monitoring practices can be further strengthened by real-time monitoring of key risk factors such as relative humidity and corrosion rates of corrodible structures. In this work, we demonstrate and validate how a 4-electrode conductivity sensor can provide a means to monitor relative humidity in gases via electrochemical impedance spectroscopy through finite element analysis (FEA). For a relative humidity range of 5%-55%, the impedance response varied from 1 kΩ to 66 kΩ, showing a high sensitivity for gas humidity. To confirm that the measured impedance values reliably interpreted relative humidity, it was found that precise estimation of the sensor's cell constant was needed. FEA was used to assess how the cell constant depended on the electrode geometry, membrane geometry, and electrode placement within the sensor. Through this approach, assumptions about the characteristic area and length were validated using electrolyte equipotential and current density vector mapping. This reduced possible cell constant uncertainties by 70%. With a cell constant of 14.84 cm^-1, obtained via FEA, membrane conductivity values were in good agreement with published data.

GalNAc glycoprotein expression by breast cell lines, primary breast cancer and normal breast epithelial membrane

Over-expression of N-acetylgalactosamine glycoproteins as detected by binding of the lectin from Helix pomatia (HPA), is associated with metastatic competence and poor patient prognosis in a range of human adenocarcinomas. These glycoproteins remain poorly characterised, and their functional role has yet to be elucidated. This study describes characterisation of a range of human breast/breast cancer cell lines for the expression of the N-acetylgalactosaminylated glycoproteins of interest, and their comparison with normal breast epithelium and a range of clinical breast carcinoma samples. Confocal and light microscopy studies revealed cytochemical HPA-binding patterns consistent with a fundamental disruption in normal glycobiosynthetic pathways attending increasing metastatic potential. We report the most complete comparative analysis of HPA-binding ligands from cultured breast cells, clinical breast carcinoma samples and normal breast epithelium to date. Lectin blotting identified 11 major HPA-binding glycoprotein bands common to both clinical tumour samples and breast cell lines and 6 of these bands were also expressed by samples of normal breast epithelium, albeit at much lower levels. Moreover, very marked quantitative but not qualitative differences in levels of expression consistent with metastatic capability were noted.

Aging lowers steady-state antioxidant enzyme and stress protein expression in primary hepatocytes

It has been reported that the isolation and culture of primary hepatocytes can compromise cellular ability to constituitively express antioxidant enzyme (AE) genes, making it difficult to study their regulation ex vivo. In the present study, the steady-state expression of manganese-containing superoxide dismutase, copper- and zinc-containing superoxide dismutase, catalase, and glutathione peroxidase was assessed in primary hepatocytes isolated from young and senescent rats and cultured in MATRIGEL: There was no change in steady-state superoxide dismutase protein or activity levels in cells collected from young animals and cultured for 7 days. Catalase expression was initially increased, and then it declined 30%. In contrast, superoxide dismutase expression declined 60% and catalase expression declined 50% in cells from senescent animals. Constitutive and inducible 70-kDa heat shock protein expression increased coincident with declining AE levels in the young cells but not senescent cells. For both age groups, electron micrographs showed rounded hepatocytes with abundant rough endoplasmic reticulum, mitochondria, and peroxisomes. Hepatocytes were organized into clusters of 6-12 cells surrounding a large central lumen devoid of microvilli. Each cluster also contained smaller microvilli-lined lumens between adjacent hepatocytes that resembled canniculi. The plasma membranes of these lumens were sealed from the extracellular space by junctional complexes. Gap junctions in the plasma membrane suggest that hepatocytes were capable of intercellular communication. We conclude that the Matrigel system can be used to study AE regulation in primary hepatocytes from young and senescent animals, provided that experiments can be conducted within a time frame of 5-7 days in culture. These data also support the hypothesis that aging compromises hepatocellular ability to maintain AE status and upregulate stress protein expression.

The relationships between neonatal encephalopathy and cerebral palsy: a cohort study

There is a high risk of cerebral palsy (CP) following neonatal encephalopathy (NE) with fits, often attributed to intrapartum asphyxia. The evidence for the association is inconclusive and antepartum factors offer an alternative explanation. A cohort study was carried out to assess the evidence for and against hypoxic ischaemic injury as the cause of NE-associated CP in term infants. A total of 57 159 consecutive births were enrolled. There were 150 cases with NE, of whom 92 had at least one fit and 58 had no fits. The incidence of all NE was 2.62 per 1000 births and of NE with fits was 1.61 per 1000 births. Infants with NE were followed-up to identify those with cerebral palsy. There were 13 cases of four-limb cerebral palsy and three with hemiplegia among the survivors. In 12 of the 13 cases of four-limb CP, a combination of low Apgar scores, an early onset acute evolving encephalopathy, acidosis, renal dysfunction and the absence of antepartum factors suggested an acute intrapartum event as the immediate cause of the NE. An obstetric event likely to cause acute hypoxic injury was identified in four of the 12 cases. The clinical picture was similar in the four with and the eight without a specific obstetric event. The pathway leading to NE-associated CP remains unexplained, but intrapartum events appear to play a major role in most cases.

Mechanisms of circulatory and intestinal barrier dysfunction during whole body hyperthermia

This work tested the hypotheses that splanchnic oxidant generation is important in determining heat tolerance and that inappropriate.NO production may be involved in circulatory dysfunction with heat stroke. We monitored colonic temperature (T(c)), heart rate, mean arterial pressure, and splanchnic blood flow (SBF) in anesthetized rats exposed to 40 degrees C ambient temperature. Heating rate, heating time, and thermal load determined heat tolerance. Portal blood was regularly collected for determination of radical and endotoxin content. Elevating T(c) from 37 to 41.5 degrees C reduced SBF by 40% and stimulated production of the radicals ceruloplasmin, semiquinone, and penta-coordinate iron(II) nitrosyl-heme (heme-.NO). Portal endotoxin concentration rose from 28 to 59 pg/ml (P < 0.05). Compared with heat stress alone, heat plus treatment with the nitric oxide synthase (NOS) antagonist N(omega)-nitro-L-arginine methyl ester (L-NAME) dose dependently depressed heme-.NO production and increased ceruloplasmin and semiquinone levels. L-NAME also significantly reduced lowered SBF, increased portal endotoxin concentration, and reduced heat tolerance (P < 0.05). The NOS II and diamine oxidase antagonist aminoguanidine, the superoxide anion scavenger superoxide dismutase, and the xanthine oxidase antagonist allopurinol slowed the rates of heme-.NO production, decreased ceruloplasmin and semiquinone levels, and preserved SBF. However, only aminoguanidine and allopurinol improved heat tolerance, and only allpourinol eliminated the rise in portal endotoxin content. We conclude that hyperthermia stimulates xanthine oxidase production of reactive oxygen species that activate metals and limit heat tolerance by promoting circulatory and intestinal barrier dysfunction. In addition, intact NOS activity is required for normal stress tolerance, whereas overproduction of.NO may contribute to the nonprogrammed splanchnic dilation that precedes vascular collapse with heat stroke.

Hitting the target: the equitable distribution of health visitors across caseloads

BACKGROUND

Health visitors in the United Kingdom work mainly with pre-school children and their mothers. Their distribution across the population is largely historical, highly variable and relates poorly to indicators of population need.

METHODS

A range of largely routine data sources were used to describe the nature, variation and statistical determinants of the workload of individual health visitors in Sheffield, England, in 1996-1997. Regression models were tested relating measures of need and deprivation to the total number of client contacts.

RESULTS

Caseloads were smaller in the most deprived areas, with wide variation. Most (93 per cent) contacts were with mothers and young children. Health visitors visited the clients designated as highest priority on average 4.7 times more often than routine clients. The main reasons for high priority ratings were child protection concerns, maternal mental health problems, child development and health concerns, and first-time mothers in the postnatal period. Half of all client contacts were with low-priority families for routine child health surveillance or were client initiated. Models based on the number of children under five and any one of a range of measures of social deprivation account for 57-59 per cent of variation in workload and could be used to allocate resources more equitably.

CONCLUSIONS

Although most health visitors apparently subscribe to the principle of targeting, the extent varies widely. Constraints on targeting are routine child health surveillance reviews, and client demands. More equitable allocation of health visitors and more explicit targeting policies might increase the effectiveness of the health visiting service.

Aging reduces adaptive capacity and stress protein expression in the liver after heat stress

A decline in an organism's ability to cope with stress through acute response protein expression may contribute to stress intolerance with aging. We investigated the influence of aging on stress tolerance and the capacity to synthesize the 70-kDa heat shock protein (HSP70) in young and old rats exposed to an environmental heating protocol. Livers were assessed for injury and HSP70 expression after heat stress by use of immunohistochemical and immunoblotting techniques. The inducible HSP70 response in the cytoplasm and nucleus was markedly reduced with age at several time points over a 48-h recovery period, although senescent rats were able to strongly express HSP70 early in recovery. Older animals had extensive zone-specific liver injury, which corresponded to the diminished HSP70 response observed in these regions, and a significant reduction in thermotolerance compared with their young counterparts. These data highlight the regional nature of stress-induced injury and HSP70 expression in the liver and the impact of aging on these responses. Furthermore, the results suggest a functional link between the age-related decrements in the expression of inducible HSP70 and the pathophysiological responses to heat stress.

School nursing: costs and potential benefits

BACKGROUND

Previous reports that variations in school nursing resources across the UK had no relationship to deprivation; controversy about the changing role of the school nursing service.

OBJECTIVES

To measure the resources allocated to school nursing, determine whether the variations can be explained by deprivation, and assess whether the allocation of school nursing time to a range of tasks is in line with current evidence and perceptions of changing needs.

STUDY DESIGN

Quantitative economic analysis; qualitative descriptive study.

SETTING

Detailed study of four English districts with diverse characteristics; staffing and service questionnaire and telephone survey of 62 districts.

MAIN MEASURES

Staff resources and their salaries; measures of population and deprivation; activity statistics.

RESULTS

There were wide variations in the cost of the school nursing service, but in contrast to previous reports 24% of the variance was explained by deprivation. There were no clear associations with any other social or educational variables. The greatest allocation of time was in routine screening and surveillance tasks. Relatively little time was allocated to other activities such as health promotion, support of special needs or unwell children, or teenage clinics. The expenditure on school nursing is only loosely related to deprivation and the results of this study offer guidance on what districts should spend to achieve equity of provision.

CONCLUSIONS

The current allocation of resources to school nursing in between districts comparisons is not equitable and the use of school nursing time is out of step with current evidence of need and effectiveness.

Levels of satisfaction of 'low-risk' mothers with their current health visiting service

AIMS AND OBJECTIVES

To assess the expressed levels of satisfaction of 'low-risk' mothers with the current health visiting service. Setting Sheffield, England, Autumn 1997.

METHODOLOGY

Self-completion, postal questionnaire (initial postcard reminder followed by a second letter and questionnaire) to a sample of 403 mothers assessed as 'low priority' by their health visitor. Questions largely related to maternal opinion of the adequacy of the health visiting service delivered during the first 9-12 months. The local research ethics committee approved the study.

RESULTS

A corrected response rate of 75% with little evidence of significant bias. A high proportion (86%) of women stated that they were either 'fairly' or 'very' satisfied with the service they had received from their health visitor with regard to their baby. A lower proportion (72%) was equally satisfied with the service they had received in respect of their own health. Despite an average number of approximately 10 contacts in relation to infant health with the health visitor during the first year of life, some 6% of women wanted more frequent contacts, particularly in the first few weeks. Study limitations The questionnaire was designed specifically for the study and validation was limited. The study population comprised a selected, 'low-risk' group.

CONCLUSIONS

The number of reported contacts with the health visitor seemed to greatly exceed those indicated by a basic child health surveillance programme. The overall level of maternal satisfaction is high, though a minority of women would like more support. Dissatisfaction was expressed with the lack of an appointment system for clinics, poor punctuality in home visits, and inappropriate or inadequate advice.

Ovariectomy does not induce osteopenia through interleukin-6 in rhesus monkeys (Macaca mulatta)

To characterize the role of interleukin-6 (IL-6) in estrogen (E2)-depletion bone loss, we utilized a nonhuman primate model of human skeletal physiology. Adult female rhesus monkeys were sham-operated (S; n = 5), ovariectomized (ovx; n = 10), or ovx followed by E2 replacement (ovx + E2; n = 10) and evaluated for the indicated parameters at 0, 3, 6, and 9 months post-ovx. Lumbar spine bone mineral density (BMD) decreased by 3 months and continued to decline through 9 months in the ovx, but not in the ovx + E2 or S groups. Middle and distal radius BMD was decreased at 9 months in the ovx, but not in the ovx + E2 or S groups. The S group had marked fluctuations in bone remodeling parameters, and cytokine levels in S animals were consistent with menstrual cycling, and therefore only those values in the ovx and ovx + E2 groups are reported. Serum osteocalcin and skeletal-specific alkaline phosphatase were elevated in the ovx group compared with the ovx + E2 group. There was no difference in serum or bone marrow plasma IL-6 levels between the ovx and ovx + E2 groups. Similarly, there was no difference in basal or phorbol ester-stimulated IL-6 levels of peripheral blood mononuclear cell or bone marrow cell culture supernatants between groups. There was no difference in serum or bone marrow soluble IL-6 receptor between groups. However, the bone marrow plasma soluble IL-6 receptor levels were transiently increased from baseline at 3 months in the ovx but not in the ovx + E2 group. In summary, there was no bone loss in the ovx + E2 group, although the serum and bone marrow IL-6 levels were similar to those of the ovx group. These data suggest that modulation of IL-6 is not the key mechanism through which estrogen deprivation mediates bone loss in rhesus monkeys.

Impact of infants born at the threshold of viability on the neonatal mortality rate in Colorado

OBJECTIVE

To determine the contribution of infants born at the threshold of viability (< 750 gm) on neonatal mortality in Colorado.

STUDY DESIGN

For the period of January 1991 to December 1996, all Colorado live births who expired were evaluated for gestational age, birth weight, gender, hospital level of care, age at time of death, delivery room resuscitation, mechanical ventilation, medical and surgical complications, and serious malformations.

RESULTS

Although infants weighing < 750 gm represent only 0.31% of all live births, they account for 46.3% of deaths. While those infants weighing < 500 gm and with a gestation of < 24 weeks almost always died (94.7%), the majority born in the 500- to 745-gm category (55.8%) survived. The vast majority (88.5%) of deaths occurred on the first day of life. A total of 38.4% of births in which the infant weighed < 750 gm occurred outside bona fide regional perinatal centers.

CONCLUSION

Future attempts to reduce the Colorado neonatal mortality rate would best focus on the 500- to 750-gm weight group through the re-regionalization of high-risk perinatal care.

Caloric restriction improves thermotolerance and reduces hyperthermia-induced cellular damage in old rats

Adult-onset, long-term caloric restriction (CR) prolongs maximum life span in laboratory rodents. However, the effect of this intervention on an organism's ability to cope with a physical challenge has not been explored. We investigated the influence of CR and aging on stress tolerance in old rats exposed to an environmental heating protocol on two consecutive days. We hypothesized that CR would increase heat tolerance by reducing cellular stress and subsequent accrual of oxidative injury. All calorically restricted rats survived both heat exposures compared with only 50% of their control-fed counterparts. CR also decreased heat-induced radical generation, stress protein accumulation, and cellular injury in the liver. In addition, heat stress stimulated marked induction of the antioxidant enzymes manganese-containing superoxide dismutase and catalase, along with strong nuclear catalase expression in liver samples from rats subjected to CR. In contrast, stress-related induction of antioxidant enzymes was blunted, and nuclear catalase expression was unchanged from euthermic conditions in the control-fed group. These data suggest that CR reduces cellular injury and improves heat tolerance of old animals by lowering radical production and preserving cellular ability to adapt to stress through antioxidant enzyme induction and translocation of these proteins to the nucleus.

Assessment of stool colour in community management of prolonged jaundice in infancy

Jaundice persisting beyond the first 2 wk of life is often regarded as an indication for investigation to exclude cholestatic liver disease. Most babies with prolonged jaundice have breast milk-related jaundice, which is a benign condition. Cholestatic liver disease is usually accompanied by pale stools and yellow or orange urine. A community programme was established to ascertain the incidence of prolonged jaundice and determine whether abnormal stool and urine colour could be used to assist primary care staff in referral decisions. Data were collected on normal stool and urine colour and used to devise a colour chart and information sheet for parents. Babies with prolonged jaundice were identified and referred for investigation. In all, 3661 babies were recruited into the study, of which 127 were jaundiced at 28 d of age. Of these, 125 were breastfed. The incidence of jaundice in breastfed babies at 28 d was 9.2% (95% CI 7.8%-11.0%) Abnormal liver function tests (LFTs) were common, but no baby had abnormal stool or urine colour and none was found to have liver disease. Jaundiced breastfed babies who are well are unlikely to have serious disease. Elevated LFTs are compatible with a diagnosis of breast milk-related jaundice. Prolonged jaundice in bottle-fed babies, and persistent pallor of stools or yellow/orange urine, are rare and merit immediate referral. Parents and professionals can be advised to report pale stools without generating a large number of unnecessary referrals. Further work is needed to determine whether a colour chart reduces the mean age of referral and treatment of infants with cholestatic liver disease.

The infant index: a new outcome measure for pre-school children's services

BACKGROUND

The evaluation of community services for preschool children is hampered by the lack of valid and routinely available outcome measures. This study examines the use of data collected by teachers in response to educational legislation to determine whether a routine measure of attainments in primary school is sensitive to factors known to affect mental development.

METHOD

A community child health dataset for the cohort of children born in Sheffield in 1990-1991 was matched with a dataset provided by schools in 1995-1996. The educational data consisted of the Infant Index scores which measure education attainments in reception class pupils.

RESULTS

We matched 4487 children from both datasets, which represented 75 per cent of all children born in the 1990-1991 cohort. Factors which predicted a poor Infant Index included male gender (odds ratio (OR) = 2.1, 95 per cent confidence interval (CI)= 1.8-2.6), low birthweight (OR = 1.4, 95 per cent CI = 1.1-1.9) and lack of breast feeding either by intention to feed (OR = 1.3, 95 per cent CI = 1.1-1.7) or actual feeding practice at one month (OR = 1.5, 95 per cent CI = 1.1-2.0). Other factors associated with a poor outcome for the child were postnatal depression, number of pregnancies, ethnicity, pre-school educational experiences and poor housing.

CONCLUSIONS

Although the results are interesting in themselves, the main significance of our project is in establishing a link between routinely collected health data and routine education data. This could facilitate research in the future thus leading to a considerable saving in the cost of long-term intervention studies.

Splanchnic tissues undergo hypoxic stress during whole body hyperthermia

Exposure of conscious animals to environmental heat stress increases portal venous radical content. The nature of the observed heat stress-inducible radical molecules suggests that hyperthermia produces cellular hypoxic stress in liver and intestine. To investigate this hypothesis, conscious rats bearing in-dwelling portal venous and femoral artery catheters were exposed to normothermic or hyperthermic conditions. Blood gas levels were monitored during heat stress and for 24 h following heat exposure. Hyperthermia significantly increased arterial O2 saturation, splanchnic arterial-venous O2 difference, and venous PCO2, while decreasing venous O2 saturation and venous pH. One hour after heat exposure, liver glycogen levels were decreased approximately 20%. Two hours after heat exposure, the splanchnic arterial-venous O2 difference remained elevated in heat-stressed animals despite normal Tc. A second group of rats was exposed to similar conditions while receiving intra-arterial injections of the hypoxic cell marker [3H]misonidazole. Liver and intestine were biopsied, and [3H]misonidazole content was quantified. Heat stress increased tissue [3H]misonidazole retention 80% in the liver and 29% in the small intestine. Cellular [3H]misonidazole levels were significantly elevated in intestinal epithelial cells and liver zone 2 and 3 hepatocytes and Kupffer cells. This effect was most prominent in the proximal small intestine and small liver lobi. These data provide evidence that hyperthermia produces cellular hypoxia and metabolic stress in splanchnic tissues and suggest that cellular metabolic stress may contribute to radical generation during heat stress.

Once- versus twice-daily gentamicin dosing in neonates >/=34 Weeks' gestation: cost-effectiveness analyses

OBJECTIVES

To compare performance and cost analysis of two gentamicin regimens in infants >/=34 weeks' gestation requiring antibiotics for a 72-hour rule-out sepsis evaluation. A once-daily dosing (ODD) regimen of 4 mg/kg was compared with a standard twice-daily dosing (TDD) regimen of 2.5 mg/kg every 12 hours.

SETTING AND DESIGN

Infants at two university-affiliated Level III nurseries were prospectively temporally allocated to receive ODD (n = 27) or TDD (n = 28) as part of their 72-hour empirical antibiotic regimen. Performance of dosing regimens was based on target serum gentamicin concentrations (SGC) established prospectively as a peak of 5 to 10 microgram/mL and a trough of </=2 microgram/mL. SGC were determined by fluorescence polarization immunoassay on day 3 of therapy. Cost data were obtained by distributing a questionnaire to 15 pediatric pharmacy practice sites. Inquiries were made regarding hospital cost of drug acquisition, drug supplies, drug preparation and administration, and serum concentration analysis. Performance and cost data were then used to do a cost-effectiveness analysis.

RESULTS

Mean peak concentrations were higher with ODD (7.9 +/- 0.2 microgram/mL) than TDD (6.7 +/- 0.3 microgram/mL). Half of the patients in the TDD group had trough concentrations >2 microgram/mL, compared with none in the ODD group. Overall, 57% of the SGCs in the TDD group were outside the target concentration range versus 7% in the ODD group. Based on questionnaire results, a total 72-hour process cost of ODD versus TDD was compared for regimens with and without use of SGC analysis. If SGCs are obtained, more than 75% of the cost associated with gentamicin therapy is attributable to SGC analysis. Based on a cost-effectiveness analysis, ODD was the dominant dosing strategy in all categories analyzed.

CONCLUSIONS

ODD of gentamicin at 4 mg/kg in neonates >/=34 weeks' gestation is the preferable treatment strategy based on: 1) significantly improved SGC performance compared with TDD; 2) elimination of the need for routine SGC collection in infants on short courses of therapy; and 3) significant antibiotic-associated hospital cost savings when compared with conventional therapy of TDD and SGC analysis.

Transition from school to adult life for physically disabled young people

The transition process for young physically disabled people (n = 87) was studied in three districts to determine how it varied between schools, and how it was perceived by the disabled and their carers. The experiences of the young people were compared with guidelines for good practice based on relevant legislation. Results showed that young disabled people experienced a poor handover to adult services if they had no "statement of special educational need" or if they went to further education college. Young people with cerebral palsy or complex multiple problems fared less well than those with spina bifida or juvenile chronic arthritis. There are several deficiencies in the legislation. Physically disabled young people should receive a transition review regardless of whether they have a "statement". The range of severity and type of disorders among the young physically disabled argues for a range of services--the category is too broad to be useful for research, service planning, and provision.

Errors in postcode to enumeration district mapping and their effect on small area analyses of health data

BACKGROUND

Health research often seeks to associate individuals to their socio-economic circumstances by linking an individual's postcode to their Census enumeration district (ED). As part of a study into health visitor resource allocation the objective here is to quantify the errors that arise in attaching ED level deprivation scores to records and counts of records by ED when records are matched to EDs via their postcodes rather than their exact address.

METHODS

The result of routine matching of postcodes to EDs was compared with the more accurate method of matching addresses to EDs. Townsend scores were then attributed to records according to the two different methods and the results compared. A sample of 4013 births registered in Sheffield in 1996 was used.

RESULTS

The comparative work showed that the mismatching of individual addresses arising from matching postcodes to EDs was 16.4 per cent. (The 95 per cent confidence interval is 15.1-17.7 per cent.) Over one-third of mismatched records (about 6 per cent of the total records) were found to have Townsend scores greater than +/- 2 compared with the score obtained through the more accurate process of address matching.

CONCLUSIONS

The evidence of the study is that it is important to recognize there are errors inherent in matching individual addresses to EDs via the address postcode. For problems involving resource allocation and for research into relationships between health outcomes or service uptake and deprivation it may be necessary to seek to quantify the level of error introduced through using postcode to ED matching.

Centrally-mediated opioid-induced immunosuppression. Elucidation of sympathetic nervous system involvement

Opioid-induced modulation of the immune system is a complex phenomenon involving opioid receptors, central and sympathetic neural pathways, catecholamine receptors, and other regulatory mechanisms. The precise neural pathways involved in centrally-mediated immune modulation are not currently defined. In addition, the physiological purpose for endogenous opioid modulation of the immune system is not well understood. Perhaps this modulation phenomenon represents an integral feedback loop within a much larger homeostatic control system. Indeed, the role of the HPA axis in immune regulation can not be discarded, and in fact, probably serves to balance immune function, in concert with multiple feedback systems, around some undiscovered parameter of efficiency. Perhaps the physiological role of endogenous opioid control is to act as a monitor poised to subvert chronic inflammatory processes and autoimmune disorders. Regardless of the evolutionary heritage of this and despite the overwhelming complexity of immune regulation, important work substantiating a bidirectional communication link between the brain and the immune system has created a foundation for further elucidation of the intricacies of immunoregulation.

Opioid mediated effects on the immune system: sympathetic nervous system involvement

Opioids have been hypothesized to suppress parameters of immune function by acting within the central nervous system to increase the activity of the hypothalamic-pituitary-adrenal axis and the sympathetic nervous system. Production of catecholamines and adrenocorticoids have been demonstrated to be responsible for many of the observed immunomodulatory effects which occur following opioid administration. In general, the sympathetic nervous system has been shown to play a role in regulating lymphocyte proliferation and natural killer cell activity as well as several other parameters of immune function. Here, we will focus primarily on the role of the sympathetic nervous system in modulating opioid induced immunosuppression. The role of the hypothalamic-pituitary adrenal axis is reviewed elsewhere in this issue.

Screening in child health

Screening programmes in child health have evolved on the basis of individual enthusiasm and professional consensus, rather than being based on objective evidence of benefit. Three reviews have been carried out in the UK over the past 10 years. The only programmes which show robust evidence of effectiveness are those for PKU and hypothyroidism. The value of screening for hearing loss and vision defects is widely accepted, but there are many unresolved issues. Programmes for detection of congenital dislocation of the hip, congenital heart disease and growth disturbances are of doubtful value. Early identification of developmental problems is stressed by parents, but screening may not be the best way to achieve this. The UK programme of well-child care places increasing emphasis on promotion of physical and emotional health; screening tests should either be subjected to quality monitoring, or removed from the programme if they cannot fulfil the classic criteria of Wilson and Jungner.

The costs of early hearing screening in England and Wales

A survey was carried out in 10 centres in England and Wales to determine the costs of hearing screening in the first year of life. The screens that were studied were targeted neonatal, universal neonatal, and the health visitor distraction test (HVDT) or alternative surveillance. Valid data were available from five centres for targeted neonatal screening (TNS), three for universal neonatal screening (UNS), and nine for the HVDT, although only five of the HVDT screens had valid data for follow up costs. The neonatal costs were consistent across the centres surveyed, whereas those for the HVDT screen varied considerably. The mean service costs for TNS, UNS, and the HVDT at 1994 prices were 5052 Pounds, 13,881 Pounds, and 24,519 Pounds for a standardised district of 1000 live births. Three conclusions seem justified. Firstly, UNS need not be prohibitively expensive as it costs considerably less than HVDT screening. Secondly, TNS appears to be a relatively inexpensive way of improving the age of identification of a proportion of the congenitally hearing impaired. Thirdly, given the published yields for UNS and the HVDT, the results indicate that UNS offers the most cost effective overall approach with alternative systems in place to identify late onset permanent hearing losses.

A re-appraisal of screening for colour vision impairments

Screening for colour vision impairments (CVI) has been carried out in schools in the UK since 1934, but little is known about its yield or value. A survey was conducted among Sheffield schoolboys, school nurses and optometrists to determine the benefits of CVI screening. The results indicated that between 4.2 and 5.2% of boys had been identified as having a CVI, compared with the expected prevalence of 8%. Boys were ill-informed about the significance of CVI for careers planning but recognized the potential importance of having this information before making decisions about choice of subjects and examinations. Possible reasons for the low yield of screening are reviewed and alternative strategies are discussed.

Fatal meconium aspiration in spite of appropriate perinatal airway management: pulmonary and placental evidence of prenatal disease

OBJECTIVE

Our purpose was to summarize eight cases of fatal meconium aspiration syndrome where pathologic review showed evidence of chronic prenatal disease and to compare these findings with those of a group of control infants and fetuses who died of other causes.

STUDY DESIGN

A 15-year retrospective chart review identified the infants who died of meconium aspiration within 48 hours of life and who also had autopsies performed. Neonatal pulmonary and available placental pathologic findings are described from these study infants and are compared with published norms and with autopsy results from a group of control infants and fetuses.

RESULTS

Seven of the eight study infants underwent suctioning of the trachea immediately after birth. In all eight cases the neonatal lungs demonstrated histologic evidence of significant hypoxic changes of a chronic nature with onset before birth. The available placentas showed variable but significant abnormalities that support a case for subacute or chronic in utero compromise.

CONCLUSIONS

As in other reports, there is evidence that meconium aspiration may be a prenatal rather than a postnatal disease. However, this is the first study that presents evidence on the basis of both pulmonary and placental pathologic findings and reinforces the importance of placental examinations in complicated pregnancies.

Assessment of maternal anxiety following neonatal screening and investigation for occult spinal dysraphism

The objective was to determine maternal anxiety and attitudes associated with a programme of neonatal screening and investigation for occult spinal dysraphism. Questionnaires were completed after diagnostic investigation (time 1) and 6 months later (time 2) by 83 mothers of babies with possible markers of occult spinal dysraphism who were normal on spinal ultrasound. Outcome measures were: attitudes to the programme; maternal adjustment and attitudes to the baby; the State-Trait Anxiety Inventory. Fifty-four other postnatal mothers formed the comparison group for maternal adjustment. No significant differences were found between investigation group (time 1) and comparisons on measures of maternal adjustment. Anxious mothers gave more negative responses to some maternal adjustment items but not to attitudes to the programme. Mean state anxiety at time 1 (33.66) and time 2 (33.69) and mean trait anxiety (36.23) were not higher than in mothers of normal babies. It can be concluded that a programme of investigation for neonatal abnormalities that pays attention to detail need not cause excessive maternal anxiety. However, some mothers remain anxious even after receiving normal results. Anxiety can be assessed during appraisal of a new investigation programme, but refinements are needed.