Understanding friction mechanisms of Si-DLC/steel interfaces under aqueous lubrication.

A key driver in current research on lubricant formulation is the need to move away from older technology that is highly reliant on resources derived from industries associated with high carbon dioxide emissions. In this paper, the adoption of water based (or aqueous) lubrication is explored. This is in direct contrast with most lubricated systems that rely on oil or other petroleum products. In nature, most known biological systems employ aqueous lubrication for tribological contacts, such as those found in cartilage and more widely in mammalian joints including hips and knees giving friction coefficients as low as µ < 0.002. This is achieved very effectively without the presence of an oil or grease as a base lubricant. In most engineering applications, however, oils and greases are used to achieve desired low friction levels. While effective, this comes with the associated higher costs and carbon footprint of using petroleum derived products. In recent years, certain engineering applications have shifted to aqueous lubrication, a notable example of which is stern tube bearings in maritime applications. These are typically low pressure contacts though. Depending on speed of travel this can range from 100-400 MPa. The research detailed in this paper explores the viability of high pressure contacts lubricated with novel aqueous packages and what effects this shift may have on friction and wear profiles of the system. The work reported herein demonstrates that with some modifications, effective lubrication can be achieved using aqueous lubricant packages.

The development of food portion sizes suitable for 4-18-year-old children used in a theoretical meal plan meeting energy and nutrient requirements.

BACKGROUND: Healthy eating guidelines for school-aged children are available but without advice on portion sizes. This is a concern because consuming large portions is associated with an increased risk of overweight/obesity. The present study aimed to calculate recommended portion sizes for school-aged children based on weight for age and use them to develop a meal plan to meet nutritional needs within energy requirements. METHODS: Portion size data on foods consumed by school-aged children (4-18 years) were extracted from two sources: (i) British National Diet and Nutrition Survey (1997) and (ii) Avon Longitudinal Study of Parents and Children (1997-2006). Foods were allocated to groups based on the UK Eatwell Guide and the US My Plate Model. Portion sizes were developed for a variety of foods. A meal plan that included portion size guidance and met healthy eating guidelines was developed based on the number of portions of each food group needed to meet dietary requirements. RESULTS: Portion sizes were developed for 131 foods that were commonly eaten by children in age groups 4-6, 7-10, 11-14 and 15-18 years. The meal plan met requirements for energy and nutrients as specified by UK dietary reference values, except for vitamin D for which there are few dietary sources. CONCLUSIONS: Food portion sizes informed by usual intake in UK children can help inform dietary advice for a range of childhood settings and for parents. The meal plan included a wide variety of foods to encourage dietary diversity and meet energy and nutrient needs for school-aged children.

The substance and sources of young children's healthy eating and physical activity knowledge: implications for obesity prevention efforts.

BACKGROUND: The prevalence of overweight among young children is increasing at an alarming rate. Global efforts to address the issue can benefit from understanding how young children's experiences across multiple contexts shape their perspectives of healthy weight. METHODS: This qualitative study examines the substance and sources of young American children's knowledge related to healthy eating, physical activity and media practices. Role play and semi-structured interviews were conducted in child-care settings with 81 children aged 3-5 who represented diverse socio-economic statuses and ethnic backgrounds. RESULTS: Children demonstrated better understanding of the benefits of healthy eating compared with physical activity. Snacks and beverages consumed outside mealtime were less likely to be healthy even among the 40% of children who demonstrated an understanding of healthy nutrition. The majority of children's leisure activity selections involved media and minimally active pursuits. Three quarters of the children were unable to articulate reasons for healthy choices or identify the sources of their health understandings. The media was listed as source of health information more frequently than adults. CONCLUSION: Obesity prevention efforts targeting young children need to use consistent messaging across all contexts in which children develop in order to increase their understanding that physical activity and eating choices support health. Efforts need to counter inaccurate information and address the rationale for health practices. Key gaps in young children's understanding include: the importance of drinking water, that snacks are part of nutritional intake and the benefits of engaging in physical activities.

Dietary nucleotides and early growth in formula-fed infants: a randomized controlled trial.

BACKGROUND: Dietary nucleotides are nonprotein nitrogenous compounds that are found in high concentrations in breast milk and are thought to be conditionally essential nutrients in infancy. A high nucleotide intake has been suggested to explain some of the benefits of breastfeeding compared with formula feeding and to promote infant growth. However, relatively few large-scale randomized trials have tested this hypothesis in healthy infants. OBJECTIVE: We tested the hypothesis that nucleotide supplementation of formula benefits early infant growth. PATIENTS AND METHODS: Occipitofrontal head circumference, weight, and length were assessed in infants who were randomly assigned to groups fed nucleotide-supplemented (31 mg/L; n=100) or control formula without nucleotide supplementation (n=100) from birth to the age of 20 weeks, and in infants who were breastfed (reference group; n=101). RESULTS: Infants fed with nucleotide-supplemented formula had greater occipitofrontal head circumference at ages 8, 16, and 20 weeks than infants fed control formula (mean difference in z scores at 8 weeks: 0.4 [95% confidence interval: 0.1-0.7]; P=.006) even after adjustment for potential confounding factors (P=.002). Weight at 8 weeks and the increase in both occipitofrontal head circumference and weight from birth to 8 weeks were also greater in infants fed nucleotide-supplemented formula than in those fed control formula. CONCLUSIONS: Our data support the hypothesis that nucleotide supplementation leads to increased weight gain and head growth in formula-fed infants. Therefore, nucleotides could be conditionally essential for optimal infant growth in some formula-fed populations. Additional research is needed to test the hypothesis that the benefits of nucleotide supplementation for early head growth, a critical period for brain growth, have advantages for long-term cognitive development.

Number of days needed to assess energy and nutrient intake in infants and young children between 6 months and 2 years of age.

OBJECTIVE: To estimate the minimum number of days of recorded dietary intake needed to place infants and young children into thirds of a population distribution with an acceptable degree of accuracy. DESIGN: Dietary intake data collected from 5-day weighed food records for 72 infants and young children up to 2 y of age, collected during a cross-sectional study, were analysed to estimate the number of recording days necessary to assess intake of energy and 10 nutrients. SETTING: Community study among healthy infants and children. SUBJECTS: Parents attended recruitment sessions in local community areas. In total, 72 subjects were entered into the study and all completed the 5-day dietary assessment period. INTERVENTIONS: A 5-day weighed record of children's dietary intake was made by the parents or regular carer. RESULTS: Mean within subject standard deviations were smaller than mean between subject standard deviations with respect to energy (778 vs 824 kJ/day), macronutrient subclasses: protein (8 vs 9.4 g/day); fat (9 vs 10 g/day); and carbohydrate (26 vs 29 g/day) and for specific micronutrients: calcium (163 vs 236 mg/day); phosphorus (143 vs 270 mg/day); magnesium (25 vs 43 mg/day); iron (2 vs 3 mg/day); zinc (1 vs 1.3 mg/day); ascorbic acid (27 vs 64 mg/day) and retinol equivalents (281 vs 424 microg/day). Estimated number of days of food records necessary to assess intake of energy, protein, fat and carbohydrate with acceptable degree of accuracy were 5,4,4 and 3, respectively. For all the micronutrients included in this analysis 2 days of recording were necessary. CONCLUSION: Compared with adults and older children, fewer days are needed to classify this age group into thirds of the distribution with an acceptable degree of accuracy according to intake of energy and specific nutrients. SPONSORSHIP: The data collection phase of this study was supported by a grant from the Procter and Gamble Company, Cincinnati, OH, USA.

Systematic review concerning the age of introduction of complementary foods to the healthy full-term infant.

OBJECTIVES: To evaluate existing data from published studies investigating outcomes (growth, nutritional status and morbidity) in relation to the age of introduction of complementary foods to the healthy full-term infant. To assess the methodological quality of current scientific evidence on which infant feeding recommendations are based. SEARCH STRATEGY: A database was created following a search of electronic databases MEDLINE and BIDS, a handsearch of relevant journals and consultation with international experts in infant feeding practices. The search was conducted during a 6-month period and encompassed the years 1982-1998. INCLUSION CRITERIA: Randomised/non-randomised controlled trials and cohort studies investigating the relationship to the health of full-term infants of the introduction of complementary foods to childhood health. DATA COLLECTION AND ANALYSIS: Assessment of studies for inclusion and their compliance with methodological criteria was undertaken independently by two reviewers and discrepancies were resolved by discussion. RESULTS: From over 400 published papers identified, 33 met specific inclusion criteria. Significant differences in baseline characteristics of subjects in included studies meant that data were not amenable to meta-analysis. The consensus of the authors was that, of the 33 included publications, 13 contained data supporting the current WHO recommendations which attempt to accommodate all infants, including those whose nutritional requirements are not met by exclusive breast-feeding for 6 months. An equal number contained data that would support a recommendation for delaying the introduction of complementary foods until 6 months of age within the study population. The remaining seven were unable to provide evidence to support a change from the current WHO infant feeding recommendations which state that 'infants should be fed exclusively on breast milk from birth to 4-6 months of age'. None of the studies met all the methodological criteria. CONCLUSIONS: This review has shown that there is a lack of clear evidence to either support or refute a change to the current recommendations for the age of introduction of complementary foods to the breast milk or formula fed infant. Whilst exclusive breast feeding for the first 6 months of life can support growth and development in some infants, sub-groups have been identified within certain populations who may require complementary feeding prior to this age.

Validation of food diary method for assessment of dietary energy and macronutrient intake in infants and children aged 6-24 months.

OBJECTIVES: To compare the estimated food diary record (ED) method against weighed intake record method (WI) for assessing dietary intake in infants and children aged 6-24 months; additionally, to compare WI with metabolisable energy intake (ME) measured by doubly labelled water (DLW) in infants aged 6 12 months. DESIGN: Cross-over study of 5 day WI vs 5 day ED. SUBJECTS: Seventy-two children aged 6-24 months. METHODS: Subjects were randomly assigned to one method during week 1 crossing over to the alternative method in week 2. Data were coded and translated into daily nutrient intakes using COMP-EAT version 5 nutritional analysis software. The analysis compared energy, protein, fat and carbohydrate. Twenty-one infants were dosed with DLW for measurement of total energy expenditure (TEE) and ME. RESULTS: Mean energy intake calculated from WI and ED was 3,782 and 3,920 kJ/day, respectively. There was no significant difference between these values. Using WI as a reference, ED showed a mean bias of 138 kJ/day, equivalent to 3.6% of mean energy intake. Limits of agreement (+/- 2 s.d. of the bias) were wide at +/- 1,385 kJ/day. There were no significant differences between methods for any of the nutrient sub-classes. Using DLW as a reference, WI showed a mean bias of 243 kJ/day, equivalent to 7.3% of mean energy intake, limits of agreement were wide at +/- 1686 kJ/day. CONCLUSION: There is no evidence from the present analysis that ED is less accurate than WI for assessing energy and nutrient sub-class intakes in groups of this age but this good agreement between methods in groups does not extend to individuals.

The ambulatory treatment unit. An innovative model.

Changes in the healthcare delivery system have created a competitive marketplace that demands new programs to contain healthcare costs while providing more efficiently for patients' healthcare needs. One major change is a trend toward outpatient ambulatory healthcare. Procedures once performed in the hospital currently are done routinely on an outpatient basis. Drug/alcohol treatment units, rehabilitation centers, and occupational health centers provide long-term care on an outpatient basis. Home healthcare programs provide nursing services for patients who are chronically ill and for those with special recovery needs after discharge; hospice programs provide nursing care for terminally ill patients. Although change can be unsettling, it also provides new opportunities for nursing to be creative and innovative in providing client services that meet present demands. This article presents one such innovation, the development of an ambulatory treatment unit.

Technology anxiety as a potential mediating factor in response to medical technology.

Technology anxiety, defined as a fear of working with medical equipment, was measured via the use of the Technology Response Questionnaire. Nurses (N = 414) working on nine types of nursing units at two hospitals participated in the study. Nurses working on psychiatric units were found to be most anxious about working with medical equipment, while nurses working on surgical and adult intensive care units were least anxious. A comparison of the nurses who were highest and lowest on technology anxiety indicated that those who were most anxious about technology were less positive toward computers, felt more stressed by their work, were lower on job satisfaction, less positive toward the physicians they worked with, lower on personality scales of autonomy and adaptability, were less likely to do care planning regularly or to use nursing diagnoses, and tended to be older than less anxious nurses.

Retinoic acid induces cyclic changes in epidermal thickness and dermal collagen and glycosaminoglycan biosynthesis rates.

The effects of daily topical application onto guinea pig ears of a therapeutic concentration of all trans-retinoic acid (RA) on epidermal thickness and dermal collagen and glycosaminoglycan (GAG) biosynthesis rates were studied during a 40-day period. Clinically, the RA-treated skin became erythematous and scaly beginning at 5-6 days, conditions which persisted throughout the experiment. The epidermis became thickened and hyperplastic with marked psoriasi-form histologic features, and the phenomenon was dependent on RA concentration. The initial hyperplasia resulted from a transient 4-fold increase in epidermal basal cell replication during the first 3-4 days, as shown by the rise and fall of [3H]thymidine labeling index which preceded the hyperplasia. The extent of epidermal hyperplasia as measured by epidermal thickness was not constant throughout the 40-day treatment period, but exhibited maxima on days 11, 25, and 36. These maxima were followed by periods of decreased thickness, although the minima were always greater than the untreated controls. Retinoic acid induced similar temporal cycles in GAG and collagen biosynthesis rates, but the collagen cycles occurred at different times with maxima on days 6, 20, and 34. After 8 weeks' treatment, the blood flow rates in the ear microcirculation (laser Doppler photometry) were increased 81% above that of the water-treated controls. The demonstration of these RA-induced cyclic changes in epidermal hyperplasia and dermal fibroblast biosynthetic activities have revealed the presence of control mechanisms in these tissues which normally operate to maintain tissue homeostasis.

Fibronectin and fibrin provide a provisional matrix for epidermal cell migration during wound reepithelialization.

Factors regulating the attachment and directional migration of a regenerating epidermis in wound healing are poorly understood. In studies of guinea pig 4-mm skin wounds, left uncovered for 1-28 days, biopsied and processed for 1-micrometer section and immunofluorescence, the epidermis migrated over an irregular thickened provisional matrix containing fibrin and fibronectin. The provisional matrix lacked two major components of normal basement membrane, laminin and type IV collagen, which can mediate tenacious epithelial attachment to plastic in vitro and may limit epidermal cell migration in vivo. Upon completion of wound reepithelialization at 7-9 days after wounding, the basement membrane zone lost its thickened appearance, fibronectin and fibrinogen disappeared, and type IV collagen and laminin reappeared. Although these findings do not prove that epidermal cell migration during reepithelialization required a fibrin and fibronectin matrix, they demonstrate that epidermal cells do move over such a substratum during in vivo wound repair.

Blood vessel fibronectin increases in conjunction with endothelial cell proliferation and capillary ingrowth during wound healing.

The regulation of angiogenesis and alterations in the structure of blood vessels taking part in wound healing are poorly understood. In studies of guinea pig 4-mm skin wound, left uncovered for 1-28 days, biopsied and processed for 1-micrometer section and immunofluorescence, we found that fibronectin in blood vessel walls markedly increased in conjunction with endothelial cell proliferation and capillary ingrowth. Both the endothelial cell proliferation and the increased vessel wall fibronectin were restricted to a 0.5-mm area along the margin of the wound and occurred 3-7 days after injury. Fibronectin was easily demonstrated in capillaries of the peripheral granulation tissue but was difficult to demonstrate in central areas of the granulation tissue secondary to a brightly fluorescent reticular background staining probably attributable to fibroblast-related fibronectin. The fibronectin in blood vessel walls rapidly diminished as endothelial cell proliferation and capillary ingrowth ceased. These data suggest that fibronectin may provide a provisional substratum for endothelial cell mitosis and movement.

Fibronectin is produced by blood vessels in response to injury.

During the time of tissue repair that ensues subsequent to tissue injury, blood vessel wall fibronectin increases concomitantly with endothelial proliferation and angiogenesis. However, the source of this blood vessel fibronectin had not been delineated. In this report we have demonstrated that microvascular fibronectin is produced in situ by the proliferating vessels surrounding excisional wounds. This finding was established by extirpating 3 mm of skin from the center of a well-healed rat xenograph on the flanks of immunosuppressed mice, harvesting the injured skin sites at various stages during the healing process, and staining the specimens with reciprocal species-specific anti-fibronectin. The proliferating donor vessels that surrounded the wounded graft had increased fluorescence staining with FITC conjugated mouse anti-rat fibronectin and no staining with rat anti-mouse fibronectin. This finding was taken as direct evidence that the fibronectin was produced in situ by the rat vessels and not derived from circulating mouse plasma.

Fibronectin in healing rabbit corneal wounds.

Fibronectin, a glycoprotein present in plasma and extracellular matrix, is believed to be involved in cell-cell and cell-matrix interactions. Using immunofluorescence techniques, we studied the time course of appearance and distribution of fibronectin in healing rabbit corneal epithelial wounds and compared fibronectin to other selected proteins in the cornea. In the normal cornea, fibronectin was detected only in Descemet's membrane and not in the epithelial basement membrane. Shortly after wounding, fibronectin deposited on the denuded corneal surface and was a continuous prominent layer by 8 hours. The epithelium had begun to migrate over the deposited fibronectin by 22 hours and by 52 hours had completely covered the denuded surface. Fibrinogen/fibrin was also detected on the initial bare wound surface. Once the wound was reepithelialized, the subepithelial fibronectin and fibrin layer then progressively disappeared, so that by 2 weeks only a small amount was detected. Fibronectin also appeared in the deep stroma of corneas after wounding in elongated patches, a pattern suggestive of keratocyte association. Fibronectin had an inverse relationship to bullous pemphigoid antigen which was used as a marker for the lamina lucida of the epithelial basement membrane. The bullous pemphigoid antigen, which was found in the normal corneal epithelial basement membrane, was removed with the epithelium and reappeared during the wound healing when fibronectin was diminishing. IgG and albumin did not localize on the wound surface, and the diffuse staining seen in the stroma did not change during healing. These findings are compatible with the hypothesis that fibronectin and fibrin play a role in epithelial migration and temporary adhesion to the surface during corneal wound healing, at a time when the normal anchoring mechanism is lost.

Acute oral testing for determining antiarrhythmic drug efficacy. I. Quinidine.

Acute oral drug testing with quinidine was used in 18 patients with high grade ventricular arrhythmia. This method involves administering a single large dose of the antiarrhythmic agent, monitoring heart rhythm by means of programmed trendscription and determining blood drug levels at selected intervals. After quinidine was given in a dose of 0.6 g, 10 patients had a positive response, defined as a 50% or greater reduction in ventricular premature beats and abolition of repetitive ectopic beats. Drug action began a mean of 88 minutes after administration, and the mean peak blood quinidine level was 3.2+/-0.5 (standard error) mug/ml. Four patients had a paradoxic increase in arrhythmia. In nine patients the response to acute drug testing was compared with the response to maintenance quinidine therapy with doses of 1.2 and 1.8 g/day. The presence of arrhythmia was assessed with 24 hour ambulatory monitoring and exercise stress testing. With both techniques, seven of nine patients showed results concordant with those of acute testing. Disparity in results of the two methods of drug administration was explained by the serum concentration of quinidine. Acute oral drug testing provides a new approach for determining expeditiously whether quinidine is effective or hazardous in an individual patient.