EffEctiveness of Prophylactic fOam dressings in the prevention of saCral pressure injuries in at-risk hospitalised patients: the EEPOC trial.

BACKGROUND: Prophylactic dressings are increasingly used to prevent pressure injuries in hospitalised patients. However, evidence regarding the effectiveness of these dressings is still emerging. This trial aims to determine the clinical and cost-effectiveness of a prophylactic silicone foam border dressing in preventing sacral pressure injuries in medical-surgical patients. METHODS: This is a multicentre, pragmatic, parallel group, randomised controlled trial. A sample size of 1320 was calculated to have >90% power to detect a 5% difference in the primary outcome at an alpha of 0.05. Adult patients admitted to participating medical-surgical wards are screened for eligibility: ≥18 years, admitted to hospital within the previous 36 h, expected length of stay of ≥24 h, and assessed high risk for hospital-acquired pressure injury. Consenting participants are randomly allocated to either prophylactic silicone foam dressing intervention or usual care without any dressing as the control group via a web-based randomisation service independent of the trial. Patients are enrolled across three Australian hospitals. The primary outcome is the cumulative incidence of patients who develop a sacral pressure injury. Secondary outcomes include the time to sacral pressure injury, incidence of severity (stage) of sacral pressure injury, cost-effectiveness of dressings, and process evaluation. Participant outcomes are assessed daily for up to 14 days by blinded independent outcome assessors using de-identified, digitally modified sacral photographs. Those who develop a sacral pressure injury are followed for an additional 14 days to estimate costs of pressure injury treatment. Analysis of clinical outcomes will be based on intention-to-treat, per-protocol, and sensitivity analyses. DISCUSSION: This trial aims to provide definitive evidence on the effect prophylactic dressings have on the development of hospital-acquired sacral pressure injuries in medical-surgical patients. A parallel economic evaluation of pressure injury prevention and treatment will enable evidence-informed decisions and policy. The inclusion of a process evaluation will help to explain the contextual factors that may have a bearing on trial results including the acceptability of the dressings to patients and staff. The trial commenced 5 March 2020 and has been significantly delayed due to COVID-19. TRIAL REGISTRATION: ANZCTR ACTRN12619000763145. Prospectively registered on 22 May 2019.

Local climate explains degree of seed dormancy in Hypericum elodes L. (Hypericaceae).

Seed dormancy and germination characteristics may vary within species in response to several factors. Knowledge of such variation is crucial to understand plant evolution and adaptation to environmental changes. We examined the correlation of climate and population genetic differentiation (ISSR) with primary seed dormancy and germination behaviour in populations of the Atlantic-European soft-water pool specialist Hypericum elodes. Primary dormancy was measured by analysing seed germination response of fresh seeds and after various periods of cold stratification. Laboratory germination experiments revealed that the single most important factor for promoting germination was cold stratification prior to placing at the germination temperature. However, in agreement with their weaker primary dormancy, the seeds germinated well when fresh, and the benefit of cold stratification was more relaxed for the southern populations. Seeds of all populations demonstrated a near absolute requirement for a light and alternating temperature regime in order to germinate. The promoting effect of alternating temperatures was particularly effective at warm temperatures (mean 20 °C) but not at cool temperatures. Whilst seed germination requirements were similar among populations, the degree of primary dormancy varied considerably and was not associated with population genetic differentiation. Primary dormancy degree was instead associated with local climate: higher temperature in summer and rainfall in winter predicted weak and rapid loss of dormancy. These results suggest that seed maturation environment may play a substantial role in explaining the degree of dormancy in H. elodes, highlighting that physiological dormancy can be modulated by local climate.

Environmentally induced transgenerational changes in seed longevity: maternal and genetic influence.

BACKGROUND AND AIMS: Seed longevity, a fundamental plant trait for ex situ conservation and persistence in the soil of many species, varies across populations and generations that experience different climates. This study investigates the extent to which differences in seed longevity are due to genetic differences and/or modified by adaptive responses to environmental changes. METHODS: Seeds of two wild populations of Silene vulgaris from alpine (wA) and lowland (wL) locations and seeds originating from their cultivation in a lowland common garden for two generations (cA1, cL1, cA2 and cL2) were exposed to controlled ageing at 45 °C, 60 % relative humidity and regularly sampled for germination and relative mRNA quantification (SvHSP17.4 and SvNRPD12). KEY RESULTS: The parental plant growth environment affected the longevity of seeds with high plasticity. Seeds of wL were significantly longer lived than those of wA. However, when alpine plants were grown in the common garden, longevity doubled for the first generation of seeds produced (cA1). Conversely, longevity was similar in all lowland seed lots and did not increase in the second generation of seeds produced from alpine plants grown in the common garden (cA2). Analysis of parental effects on mRNA seed provisioning indicated that the accumulation of gene transcripts involved in tolerance to heat stress was highest in wL, cL1 and cL2, followed by cA1, cA2 and wA. CONCLUSIONS: Seed longevity has a genetic basis, but may show strong adaptive responses, which are associated with differential accumulation of mRNA via parental effects. Adaptive adjustments of seed longevity due to transgenerational plasticity may play a fundamental role in the survival and persistence of the species in the face of future environmental challenges. The results suggest that regeneration location may have important implications for the conservation of alpine plants held in seed banks.

Seed dormancy and germination in three Crocus ser. Verni species (Iridaceae): implications for evolution of dormancy within the genus.

The aim of this work was to examine whether seed ecophysiological traits in three closely related Crocus species were associated with ecological niche differentiation and species divergence. Seeds of the temperate tetraploid cytotype of Crocus neapolitanus, the sub-Mediterranean C. etruscus and the Mediterranean C. ilvensis were placed either on agar in the laboratory under different periods of simulated seasonal conditions or in nylon mesh bags buried outdoors to examine embryo growth, radicle and shoot emergence. In agreement with the phenology observed outdoors, in the laboratory embryos required a cool temperature (ca. 10 °C) to grow to full size (embryo length:seed length, E:S ratio ca. 0.75) but only after seeds received a warm stratification; radicle emergence then followed immediately (November). Shoot emergence is a temporally separated phase (March) that was promoted by cold stratification in C. neapolitanus while in the other two species this time lag was attributed to a slow continuous developmental process. These species have similar embryo growth and radicle phenology but differ in their degree of epicotyl dormancy, which is related to the length of local winter. Conclusions from laboratory experiments that only consider root emergence could be misleading; evaluating the phenology of both root and shoot emergence should be considered in order to demonstrate ecologically meaningful differences in germination behaviour and to develop effective propagation protocols. Although these taxa resulted from recent speciation processes, the outcomes suggest an early onset of adaptation to local ecological factors and that phylogeny may represent a significant constraint in the evolution and expression of seed traits in Crocus.

Temperature controls seed germination and dormancy in the European woodland herbaceous perennial Erythronium dens-canis (Liliaceae).

We examined the germination ecology and the temperature requirements for germination of Erythronium dens-canis, under both outdoor and laboratory conditions. E. dens-canis is a spring flowering woodland geophyte widely distributed across Europe. Germination phenology, including embryo development and radicle and cotyledon emergence, were investigated in a natural population growing in Northern Italy. Immediately after harvest, seeds of E. dens-canis were either sown on agar in the laboratory under simulated seasonal temperatures or placed in nylon mesh sachets and buried in the wild. Embryos, undifferentiated at the time of seed dispersal, grew during summer and autumn conditions in the laboratory and in the wild, culminating in radicle emergence in winter when temperatures fell to ≈ 5 °C. Emergence of cotyledons did not occur immediately after radicle emergence, but was delayed until the end of winter. Laboratory experiments showed that temperature is the main factor controlling dormancy and germination, with seeds becoming non-dormant only when given warmth, followed by cold stratification. Unlike seeds of E. dens-canis that germinate in winter, in other Erythronium species radicle emergence occurs in autumn, while in some it is delayed until seeds are transferred from winter to spring conditions. Our results suggest that there is genetic and environmental control of the expression of seed dormancy amongst Erythronium species, which is related to local climate.

The influence of cone age on the relative longevity of Banksia seeds.

BACKGROUND AND AIMS: Serotiny is common in the genus Banksia, so any seed collection is likely to be comprised of seeds that were produced in many different years. This study aimed to determine the impact of cone age and degree of serotiny on longevity in ex situ storage. METHODS: Cones of identifiable age classes were collected from three species of Banksia. Seeds were extracted from cones and the degree of serotiny calculated. An estimate of initial viability (K(i)), the time for viability to fall by one probit (σ) and the relative longevity of seeds (p(50)) for each species and cone age class was determined using a comparative longevity test (50 °C, 63 % relative humidity). KEY RESULTS: The degree of serotiny ranged from moderate (7·9) for Banksia attenuata to strong (40·4) for B. hookeriana. Survival curves for all seed age classes within each species could be described by regressions with a common slope (1/σ), but with different values for K(i). The time taken for viability to fall by one probit (σ) could be described by a common value (29·1 d) for all three species. CONCLUSIONS: Differences in seed longevity between cone age classes and species was related to variation in initial viability (K(i)) rather than to differences in σ. While targeting the youngest mature seed cohort on a plant will maximize the viability of seeds collected, a wide range of age classes should be collected (but stored as separate cohorts if possible) for quality conservation/restoration seed collections where genetic diversity is important.

Posttraumatic stress reactions after injury.

BACKGROUND: Many individuals experience psychological distress after injury. It is unclear whether poor psychological outcome reflects pretrauma variables. METHODS: In a prospective, cross-sectional study, 152 accident and emergency department patients with physical injuries and an acute stress reaction completed trauma and psychometric questionnaires, including the Impact of Event Scale and the Hospital Anxiety and Depression Scale. RESULTS: Although levels of pretrauma social, occupational, and familial functioning were high, and the modal Abbreviated Injury Scale score was 1, there were high levels of psychological distress at 3 weeks. Mean Hospital Anxiety and Depression Scale anxiety and depression scores were 11.8 (SD, 4.4) and 8.7 (SD, 4.4), respectively. The mean total Impact of Event Scale score was 46.0 (SD, 16.1). Stepwise linear regression analysis found unemployment and previous history of trauma to be associated with increased symptoms of traumatic stress. CONCLUSION: Trauma patients with high levels of pretrauma functioning may develop acute psychological distress. Unemployment and previous trauma increase risk. Psychological wellbeing should be considered in routine injury assessments.

The Evaporation Resistance of Mixed Monolayers of Octadecanol and Cholesterol.

The high resistance to water evaporation exhibited by monolayers of octadecanol is markedly reduced if small quantities of cholesterol are present, an effect that mirrors the behavior of contaminants in octadecanol monolayers. Surface pressure-area isotherms show that octadecanol and cholesterol are almost (but not entirely) immiscible. Grazing-incidence synchrotron X-ray diffraction (GIXD) of the floating monolayers shows that cholesterol produces no diffraction pattern and thus is amorphous, octadecanol gives a clear diffraction peak which can be deconvoluted into a major and a minor peak corresponding to a slightly distorted hexagonal packing of the alkyl chains, and the alcohol-rich mixtures give diffraction patterns like that of pure octadecanol. The latter result shows that cholesterol does not enter the octadecanol domains in the mixed monolayers. The evaporation data are explained by permeation through the irregularly packed domain boundary regions in a pure octadecanol monolayer and by the rapid increase in the size of these regions when cholesterol is added. Copyright 1998 Academic Press.

GERMINATION RESPONSES TO LIGHT AND ALTERNATING TEMPERATURES IN EUROPEAN POPULATIONS OF DACTYLIS GLOMERATA L.: V. THE PRINCIPLE COMPONENTS OF THE ALTERNATING TEMPERATURE REQUIREMENT.

Detailed germination responses to temperature and light in two populations of Dactylis glomerata L. originating from S.E. Denmark and W. France were defined using thermogradient bars. Despite quantitative differences patterns of response were broadly similar. In both cases seeds were sensitive to the relative periods spent at the warm and cool phases of alternating temperature cycles with germination markedly reduced in diurnal cycles involving a 16 h warm phase and an 8 h cool phase. Whereas the proportion of seeds capable of germination increased sharply as the amplitude of temperature alternation increased the optimum amplitude was dependent on both the period spent at each phase and the presence or absence of light. Even under optimum temperature conditions there was an overriding requirement for light in a high proportion of individuals. When five 21/11 °C cycles of reduced duration were applied at 24 h intervals, 1 h/2 h alternations were as effective in stimulating germination as diurnal cycles. Germination response was directly related to the logarithm of the number of diurnal 21/11 °C cycles applied in three different seed samples. Sensitivity was not related to inherent dormancy status (between populations) or to a degree of after-ripening.

GERMINATION RESPONSES TO LIGHT AND ALTERNATING TEMPERATURES IN EUROPEAN POPULATIONS OF DACTYLIS GLOMERATA L.: IV. THE EFFECTS OF STORAGE.

A direct linear relationship between germination responses to light and alternating temperatures and storage period was recorded when seeds of three populations of Dactylis glomerata L. of contrasting origin were stored under cool dry laboratory conditions (15°C, 15% r.h.). Under these conditions the rate of after-ripening in two batches of a Mediterranean population were independent of original dormancy level but lower than in populations originating from southern England and Western France. The effects of storage on germination responses were additive in all cases. In contrast, when seeds of a population from southern England were stored under natural conditions of temperature and humidity from August to April germination behaviour was dependent on the conditions used in germination tests. Evidence is presented that the rate of loss of primary dormancy under natural conditions exceeded that which occurred during controlled storage in the laboratory. An apparent simultaneous loss of primary dormancy and induction of secondary dormancy observed when seeds were stored under natural conditions is discussed. Dry storage at -75°C effectively arrested after-ripening over a period of 110 weeks.