Search

Aim Pressure related skin injuries (including ulceration, skin/epithelial stripping, and combination injuries) have historically been neglected within neonatal research. Although anecdotal evidence, wound reviews and isolated case studies have been published; there is limited research specific to neonatal pressure injuries despite this population being, arguably, the most vulnerable patient group. The objective of this study was to investigate specific rates of neonatal skin breakdown from pressure including locations, stages, and etiology associated with tissue damage. Methods A descriptive cohort study was conducted in North Queensland's Tertiary perinatal center over a 2-year period. Prevalence audits for pressure injuries to the skin were conducted (including epithelial stripping) and incorporated categorization of with degree of tissue breakdown between Stage 1–4. A modified risk assessment and prevalence tool was utilized in this study. Results 247 neonatal patients were reviewed during the study period, of these infants, 77/247 were identified as having a skin injury (a prevalence rate of 31.2%). In total, 107 injuries were identified with the mean number of 1.4 injuries (range 1–4, SD 0.71). The mean gestational age was 28 weeks (range 22–41 weeks, SD 4.1 weeks) and the mean birth weight was 1155 g (range 445–2678 g, SD 620 g). Factors identified as contributing to pressure injuries included indwelling vascular catheters (22.4%), non-invasive continuous positive airway pressure delivery devices (14.0%), oxygen saturation and temperature probes (17.8.%). 31.8% of injuries could not be associated with a specific risk factor. Conclusions Neonates are undeniably at risk for pressure injuries however; it is still unclear which proportions of injuries are entirely preventable. Further development of a risk assessment and prevalence tool will provide practitioners with insight into the specific risk factors applicable for neonatal pressure injuries. Additional studies with larger patient groups will more accurately update practice related to pressure injury prevention and management in neonatal units; as well as critically evaluate the adverse affects of routine care processes that unintentionally harm the skin of these fragile patients.

There are a variety of relatively new, and some old and persisting, empirical issues confronting scholars of credentialing. Success in understanding these matters will be aided by greater theoretical and methodological precision and sophistication, and by avoidance of morality-driven assumptions about these topics. This paper discusses both promising and problematic aspects of current credentialing research.

Understanding the role of inclusions in the fracture process is of great importance and up to now there have been few continuum solutions which give elasto-plastic stress and strain fields around an inclusion. The incremental solution presented is for plane strain conditions, the cylindrical inclusion being assumed rigid, while the matrix obeys the Mises yield criterion and its associated flow rule and has a very small or zero linear work-hardening characteristic. On the infinite boundary, strains of up to nearly 16× yield strain are applied under various states of stress, varying from pure shear to the nearly purely hydrostatic state. The simultaneous governing equations in terms of displacements are solved using finite differences and successive over-relaxation. The results presented give distributions of radial stress and shear strain on the matrix-inclusion interface showing the variation with applied strain and stress state, and work-hardening characteristic: shear strains are found to be almost independent of stress state. Comparison is made with the linear viscoelastic solution and a slip-line solution is attempted from a plot of maximum shear strain trajectories.

The effect of stress state on the effective plastic strain to initiate ductile failure in three high strength steels is investigated. Circumferentially notched tension specimens were used, and failure initiation strains were correlated with a parameter which is a measure of the “triaxiality” of the stress state. Results are given for both in-plane and through-thickness directions in rolled plate. The failure initiation data, together with appropriate stress-strain fields, and estimates of characteristic lengths over which failure initiates, have been used to predict failure initiation at notches and at crack tips; conventional fracture mechanics parameters, such as KI at crack extension in small scale yielding are estimated for one of the high strength steels.

Ethynylation of 1,2:5,6-di- O -isopropylidene-α- D -ribo-hexofuranos-3-ulose ( 1 ) gave the 3- C -ethynyl allo derivative 2 , together with an adduct ( 3 ) resulting from interaction of two molecules of 1 with one of acetylene. Lithium aluminum hydride reduced the acetylenes 2 and 3 to the corresponding alkenes 4 and 8 ; on sequential ozonolysis-borohydride reduction, these both gave 3- C -(hydroxymethyl)-1,2:5,6-di- O -isopropylidene-α- D -allofuranose ( 6 ), further characterized as its 3,3 1 -cyclic carbonate 9 . Ozonolysis of the acetylene 2 gave the 3 1 ,5-lactone ( 5 ) of the 3- C -carboxy analog, thus establishing the stereochemistry of 2, which was independently established by n.m.r. spectroscopy employing a lanthanide shift-reagent. Treatment of 2 with mercuric acetate in ethyl acetate, followed by hydrogen sulfide, gave a mixture of the 3- C -acetyl-3- O -acetyl derivative 10 and a product ( 11 ) derived from internal cyclization of 5,6-deacetonated, O -deacetylated 10 . Reduction of 10 with lithium aluminum hydride gave a separable mixture of diastereoisomeric 3- C -(l-hydroxy-ethyl) derivatives ( 12a , 12b ) that were individually converted into their corresponding 3,3 1 -cyclic carbonates 13a and 13b , products that contain the branch functionality of the unusual, branched-chain sugar aldgarose.

A short resume is given of the solution to the plane elastic problem of an elliptical hole under uniaxial tension at any angle. The expression for the stresses and displacements, for both plane stress and plane strain, are explicitly given, and, by superposition of an applied stress at 90° to the first applied stress, any two-dimensional stress state can be simulated. A computer program is presented, enabling numerical values of stress and displacements for such stress states to be calculated on the free surface and at discrete points in the field for any ellipse, including the sharp crack.

Distributions of stress and plastic strain at the minimum diameter in circumferentially notched bars with three different notch profiles are deduced from observation of the displacements of bands within the material and a modified Bridgman analysis. The strain distributions were found to be non-linear; the degree of non-linearity being dependent on the degree of straining and strongly dependent upon notch geometry, which cannot be described only by the ratio of the minimum radius to the profile radius. For two of the three profiles studied the longitudinal stress distributions were found to be nearly uniform across the minimum diameter whilst the third was found to be extremely non-uniform. Qualitative confirmation of the strain distribution results were obtained by use of transversely orientated specimens.