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Drop-on-demand (DoD) ink-jetting of hard particle suspensions with volume fraction Φ ~ 0.25 has been surveyed using 1000 ultra-high speed videos as a function of particle size (d90 = 0.8--3.6 μm), with added 2 wt. % acrylic (250 kDa) or 0.5 wt. % cellulose (370 kDa) resin, and also compared with Newtonian analogues. Jet break-off times from 80 μm diameter nozzles were insensitive (120 ± 10 μs) to particle size, and resin jet break-off times were not significantly altered by >30 wt. % added particles. Different particle size grades can be jetted equally well in practice, while resin content effectively controls DoD break-off times. [ABSTRACT FROM AUTHOR]

Synopsis The biology and physical properties of the uniquely human skin cream ‘vernix caseosa’ are discussed. This material coats the foetal skin surface during the last trimester of gestation and provides multiple beneficial functions for the foetus and newborn infant. Vernix has a complex structure similar to stratum corneum but lacks lipid lamellae and is more plastic due to the absence of desmosomal constraints. In utero, vernix is made in part by foetal sebaceous glands, interacts with pulmonary surfactant, detaches into the amniotic fluid, and is swallowed by the foetus. At the time of birth, vernix has a remarkably constant water content approximating 80%. Postnatally, vernix is simultaneously a cleanser, a moisturizer, an anti-infective, and an anti-oxidant. Vernix facilitates acid mantle development and supports normal bacterial colonization. Its hydrated cellular structure and unusual lipid composition provide a ‘best’ solution for the needs of the foetus and newborn, not least of which is the attraction of caregivers. Vernix is an important natural biomaterial of potential interest to cosmetic scientists, and other disciplines involved in product development and therapies targeting the complex interface between the stratum corneum and a changing terrestrial environment. [ABSTRACT FROM AUTHOR]

Jets from drop-on-demand inkjet print-heads consist of a main drop with a trailing filament, which either condenses into the main drop, or breaks up into satellite drops. Filament behaviour is quantitatively similar to that of larger, free symmetrical filaments, and can be predicted from the aspect ratio and Ohnesorge number. Symmetrical filaments generated from inkjet print-heads show the same behaviour. A simple model, based on competition between the processes of axial shortening and radial necking, predicts the critical aspect ratio below which the jet condenses into a single drop. The success of this simple criterion supports the underlying physical model. [ABSTRACT FROM AUTHOR]

Aim. This paper is a discussion of evidence-based core measures for developmental care in neonatal intensive care units. Background. Inconsistent definition, application and evaluation of developmental care have resulted in criticism of its scientific merit. The key concept guiding data organization in this paper is the United States of America's Joint Commission's concept of 'core measures' for evaluating and accrediting healthcare organizations. This concept is applied to five disease- and procedure-independent measures based on the Universe of Developmental Care model. Data sources. Electronically accessible, peer reviewed studies on developmental care published in English were culled for data supporting the selected objective core measures between 1978 and 2008. The quality of evidence was based on a structured predetermined format that included three independent reviewers. Systematic reviews and randomized control trials were considered the strongest level of evidence. When unavailable, cohort, case control, consensus statements and qualitative methods were considered the strongest level of evidence for a particular clinical issue. Discussion. Five core measure sets for evidence-based developmental care were evaluated: (1) protected sleep, (2) pain and stress assessment and management, (3) developmental activities of daily living, (4) family-centred care, and (5) the healing environment. These five categories reflect recurring themes that emerged from the literature review regarding developmentally supportive care and quality caring practices in neonatal populations. This practice model provides clear metrics for nursing actions having an impact on the hospital experience of infant-family dyads. Conclusion. Standardized disease-independent core measures for developmental care establish minimum evidence-based practice expectations and offer an objective basis for cross-institutional comparison of developmental care programmes. [ABSTRACT FROM AUTHOR]

A simple experimental device is presented, which can produce droplets on demand or in a continuous mode and provides a large-scale model for real inkjet printing systems. Experiments over different regimes of Reynolds and Weber number were carried out to test the system. The ranges of Reynolds and Weber numbers were adjusted by modifying the liquid properties or the jetting parameters. Reynolds numbers from 5.6 to 1000 and Weber numbers from 0.5 to 160 were obtained using water/glycerol mixtures in the drop-on-demand mode and Reynolds numbers from 30 to 5500 and Weber numbers from 20 to 550 for the continuous jet mode. The nozzle diameter can be varied from 0.15 to 3.00 mm and drop velocities were achieved in the range from 0.3 to 6.0 m/s depending on the jetting parameters and the driving mode. Keywords: Droplet, printer nozzle, drop on demand and continuous jet. [ABSTRACT FROM AUTHOR]

Neurosensory cutaneous discomfort in response to topical products is common, yet the relationship between symptoms such as stinging and visible irritation is currently unclear. The presence of a polymorphism at position -308 on the TNF-α gene has been associated with skin irritation, i.e., erythema, dryness. Individuals with a G to A transition (AA/GA genotypes) have a lower threshold to experimentally induced irritation than those with the wild type (G allele, GG genotype). We investigated the effect of this polymorphism on neurosensory irritation (NSI). DNA genotyping was used to determine the allele type amongst a population of health care workers. The neurosensory response to lactic acid and water on the nasolabial folds and hands was assessed using a quantitative lactic acid sting test. Both genotypes had a more intense response to lactic acid compared with water on the face. The AA/GA genotypes had directionally higher scores from lactic acid ( P = 0.1) and significantly higher stinging intensities from water ( P = 0.001) on the face. For the hands, stinging intensities were higher for lactic acid and water amongst the AA/GA genotypes ( P = 0.03 and 0.006 respectively). NSI to lactic acid was significantly higher on the face than on the hands ( P < 0.05). Our findings indicate that subjects with the A transition at position -308 on the TNF-α gene experience more intense NSI with common ingredients, i.e., lactic acid and water, than those with the wild type. TNF-α polymorphism -308 may account for some of the inter-individual variability in response to skin care practices. [ABSTRACT FROM AUTHOR]

This paper describes the design and initial results from the “Cambridge Trimaster,” a recently developed high speed filament stretch and break-up device that can be used for viscoelastic fluids with shear viscosities as low as 10 mPa s. Extensional viscosity and filament break-up behavior were studied optically using a high speed camera and extensional viscosity values determined for a series of mono-disperse polystyrene solutions up to a weight concentration of 5 wt % were measured as a function of the polymer loading. The transient stretching and break-up profiles recorded with the apparatus were observed and correlated with drop formation for drop-on-demand inkjet printing fluids. This allowed the filament break-up behavior to be ranked in terms of satellite drop and droplet filament behavior. Correlation with previous work on the jetting of similar low viscosity viscoelastic polymer solutions demonstrated the ability of this apparatus to characterize inkjet fluids. [ABSTRACT FROM AUTHOR]