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1.
Proc Biol Sci ; 289(1989): 20221649, 2022 12 21.
Article in English | MEDLINE | ID: mdl-36515119

ABSTRACT

Ecosystem structure and function are increasingly threatened by changing climate, with profound effects observed globally in recent decades. Based on standardized visual censuses of reef biodiversity, we describe 27 years of community-level change for fishes, mobile macroinvertebrates and macroalgae in the Tasmanian ocean-warming hotspot. Significant ecological change was observed across 94 reef sites (5-10 m depth range) spanning four coastal regions between three periods (1992-95, 2006-07, 2017-19), which occurred against a background of pronounced sea temperature rise (+0.80°C on average). Overall, fish biomass increased, macroinvertebrate species richness and abundance decreased and macroalgal cover decreased, particularly during the most recent decade. While reef communities were relatively stable and warming was slight between the 1990s and mid-2000s (+0.12°C mean temperature rise), increased abundances of warm affinity fishes and invertebrates accompanied warming during the most recent decade (+0.68°C rise). However, significant rises in the community temperature index (CTI) were only found for fishes, invertebrates and macroalgae in some regions. Coastal warming was associated with increased fish biomass of non-targeted species in fished zones but had little effect on reef communities within marine reserves. Higher abundances of larger fishes and lobsters inside reserves appeared to negate impacts of 'thermophilization'.


Subject(s)
Ecosystem , Seaweed , Animals , Biodiversity , Invertebrates , Temperature , Fishes , Coral Reefs
2.
Musculoskeletal Care ; 19(4): 473-483, 2021 12.
Article in English | MEDLINE | ID: mdl-33683799

ABSTRACT

BACKGROUND: This study assessed the measurement properties of two commonly used self-report physical activity (PA) measures: the International Physical Activity Questionnaire-Short Form (IPAQ-SF) and the Physical Activity Scale for the elderly (PASE) in adults with osteoarthritis. METHODS: Secondary analysis of the MOSAICS cluster randomised controlled trial baseline and 3-month follow-up questionnaires, total scores and subdomains of the IPAQ-SF and PASE were compared. Intra-class correlations (ICC) were used to assess test-retest reliability, measurement error was assessed using standard error of measurement (SEM), smallest detectable change (SDC) and 95% limits of agreement (LoA). Responsiveness was assessed using effect size (ES), standard responsive measurement (SRM) and response ratio (RR). RESULTS: There was moderate correlation (r = 0.56) between the total IPAQ-SF scores (score ranges 0-16,398) and the total PASE scores (score ranges 0-400). Subdomain correlations were also moderate (ranges 0.39-0.57). The PASE showed greater reliability compared to the IPAQ-SF (ICC = 0.68; 0.61-0.74 95% CI and ICC = 0.64; 0.55-0.72, respectively). Measurement errors in both measures were large: PASE SEM = 46.7, SDC = 129.6 and 95% LoA ranges = -117 to 136, the IPAQ-SF SEM = 3532.2 METS-1 min-1 week , SDC = 9790.8 and 95% LoA ranges = -5222 to 5597. Responsiveness was poor: ES -0.14 and -0.16, SRM -0.21 and -0.21, and RR 0.12 and 0.09 for the IPAQ-SF and PASE, respectively. DISCUSSION: The IPAQ-SF and PASE appear limited in reliability, measurement error and responsiveness. Researchers and clinicians should be aware of these limitations, particularly when comparing different levels of PA and monitoring PA levels changes over time in those with osteoarthritis.


Subject(s)
Exercise , Osteoarthritis , Adult , Aged , Exercise/physiology , Humans , Randomized Controlled Trials as Topic , Reproducibility of Results , Surveys and Questionnaires
3.
Proc Biol Sci ; 287(1941): 20201798, 2020 12 23.
Article in English | MEDLINE | ID: mdl-33352078

ABSTRACT

Primary productivity of marine ecosystems is largely driven by broad gradients in environmental and ecological properties. By contrast, secondary productivity tends to be more variable, influenced by bottom-up (resource-driven) and top-down (predatory) processes, other environmental drivers, and mediation by the physical structure of habitats. Here, we use a continental-scale dataset on small mobile invertebrates (epifauna), common on surfaces in all marine ecosystems, to test influences of potential drivers of temperature-standardized secondary production across a large biogeographic range. We found epifaunal production to be remarkably consistent along a temperate to tropical Australian latitudinal gradient of 28.6°, spanning kelp forests to coral reefs (approx. 3500 km). Using a model selection procedure, epifaunal production was primarily related to biogenic habitat group, which explained up to 45% of total variability. Production was otherwise invariant to predictors capturing primary productivity, the local biomass of fishes (proxy for predation pressure), and environmental, geographical, and human impacts. Highly predictable levels of epifaunal productivity associated with distinct habitat groups across continental scales should allow accurate modelling of the contributions of these ubiquitous invertebrates to coastal food webs, thus improving understanding of likely changes to food web structure with ocean warming and other anthropogenic impacts on marine ecosystems.


Subject(s)
Coral Reefs , Invertebrates/physiology , Animals , Australia , Biomass , Ecosystem , Fishes , Food Chain , Humans , Kelp , Oceans and Seas , Predatory Behavior , Temperature
4.
Facts Views Vis Obgyn ; 11(2): 111-117, 2019 Jun.
Article in English | MEDLINE | ID: mdl-31824632

ABSTRACT

BACKGROUND: Surgery for deep endometriosis often requires input from urological surgeons. This study aims to determine pre-operative and intra-operative factors that influence the need for urological input in laparoscopic resection of rectovaginal endometriosis and to assess the usefulness of a scoring system to predict this. METHODS: We conducted a retrospective cohort study of 230 patients undergoing laparoscopic excision of deep endometriosis, at a tertiary referral centre for endometriosis in London UK, 2011 to 2015. Data from pre-operative assessment, surgery and post-operative follow up were analysed and patients were categorised according to their pre-operative and intra-operative risk factors. The primary outcome measure was the requirement of intra-operative input by urological surgeons. RESULTS: The median age was 35 years. In addition to the excision of endometriosis, 19.6% patients (45 patients) underwent hysterectomy, 14.8% (34 patients) required JJ stent placement, 6.1% (14 patients) had bowel resections and 2.6% (6 patients) required an ileostomy. 93.9% (216 patients) were considered normal-risk pre-operatively, of whom 89.4% (193/216) did not require any intra-operative urological input. 10.6% of this normal-risk group (23/216) required JJ stents, of whom 69.6% (16/23) also required a hysterectomy or bowel resection. Post operative complications occurred in 0.9% (2/216) of normal-risk patients, with none having required intra-operative urological reconstruction.Six percent (14 patients) were deemed to be increased-risk pre-operatively, of whom 78.6% (11/14) required JJ stent insertion. Thirty-six percent of increased-risk patients (5/14) had pre-operative renal dysfunction demonstrated on MAG3/DMSA and 80.0% of these (4/5) required intra-operative ureteric reconstruction. CONCLUSIONS: Patients considered normal-risk pre-operatively, planned for excision, without hysterectomy or bowel resection, can be safely managed without specific urology input. Patients with risk-features are highly likely to require urological input, particularly for JJ stent insertion. Patients with pre-operative renal dysfunction, demonstrated on MAG3/DMSA, have a high chance of requiring intra-operative ureteric reconstruction and are best managed with pre-planned reconstructive urologist input.

5.
Proc Natl Acad Sci U S A ; 116(9): 3919-3928, 2019 02 26.
Article in English | MEDLINE | ID: mdl-30808769

ABSTRACT

Ebola virus disease (EVD) often leads to severe and fatal outcomes in humans with early supportive care increasing the chances of survival. Profiling the human plasma lipidome provides insight into critical illness as well as diseased states, as lipids have essential roles as membrane structural components, signaling molecules, and energy sources. Here we show that the plasma lipidomes of EVD survivors and fatalities from Sierra Leone, infected during the 2014-2016 Ebola virus outbreak, were profoundly altered. Focusing on how lipids are associated in human plasma, while factoring in the state of critical illness, we found that lipidome changes were related to EVD outcome and could identify states of disease and recovery. Specific changes in the lipidome suggested contributions from extracellular vesicles, viremia, liver dysfunction, apoptosis, autophagy, and general critical illness, and we identified possible targets for therapies enhancing EVD survival.


Subject(s)
Critical Illness/epidemiology , Hemorrhagic Fever, Ebola/genetics , Lipid Metabolism/genetics , Lipids/genetics , Adolescent , Adult , Child , Disease Outbreaks , Ebolavirus/genetics , Ebolavirus/pathogenicity , Female , Gene Expression Regulation/genetics , Hemorrhagic Fever, Ebola/blood , Hemorrhagic Fever, Ebola/pathology , Hemorrhagic Fever, Ebola/virology , Humans , Lipids/blood , Male , Sierra Leone/epidemiology , Young Adult
6.
Mar Pollut Bull ; 130: 159-169, 2018 May.
Article in English | MEDLINE | ID: mdl-29866542

ABSTRACT

Pollution increasingly impacts healthy functioning of marine ecosystems globally. Here we quantify concentrations of major pollutant types (heavy metals/sewage/petrochemicals/plastics) as accumulated within marine sediments on and/or immediately adjacent to shallow reefs for 42 sites spanning coastal population centres across south-eastern Australia. Gradients in pollutants were revealed, but few pollutants co-varied, while increasing wave exposure ostensibly diluted concentrations of all pollutants except microplastics. Examination of reef biodiversity indicators revealed that maximum size of fauna and flora, a key life-history parameter summarised by the Community shortness index, plus declining functional and species richness, were the most sensitive bioindicators of pollutants - for which heavy metals and nutrient-enrichment were most pervasive. Results indicate that assemblages of biogenic habitat formers and associated fauna collapse from "long and complicated" to "short and simplified" configurations in response to increasing pollution, and this community signature may form an effective bioindicator to track human-driven degradation.


Subject(s)
Biodiversity , Coral Reefs , Metals, Heavy/toxicity , Plastics/toxicity , Sewage/adverse effects , Animals , Australia , Ecosystem , Environmental Pollutants/analysis , Environmental Pollutants/toxicity , Environmental Pollution/adverse effects , Fishes , Invertebrates , Metals, Heavy/analysis , Seaweed , Sewage/analysis
7.
Bone Joint Res ; 6(2): 82-89, 2017 Feb.
Article in English | MEDLINE | ID: mdl-28167489

ABSTRACT

OBJECTIVES: All-suture anchors are increasingly used in rotator cuff repair procedures. Potential benefits include decreased bone damage. However, there is limited published evidence for the relative strength of fixation for all-suture anchors compared with traditional anchors. MATERIALS AND METHODS: A total of four commercially available all-suture anchors, the 'Y-Knot' (ConMed), Q-FIX (Smith & Nephew), ICONIX (Stryker) and JuggerKnot (Zimmer Biomet) and a traditional anchor control TWINFIX Ultra PK Suture Anchor (Smith & Nephew) were tested in cadaveric human humeral head rotator cuff repair models (n = 24). This construct underwent cyclic loading applied by a mechanical testing rig (Zwick/Roell). Ultimate load to failure, gap formation at 50, 100, 150 and 200 cycles, and failure mechanism were recorded. Significance was set at p < 0.05. RESULTS: Overall, mean maximum tensile strength values were significantly higher for the traditional anchor (181.0 N, standard error (se) 17.6) compared with the all-suture anchors (mean 133.1 N se 16.7) (p = 0.04). The JuggerKnot anchor had greatest displacement at 50, 100 and 150 cycles, and at failure, reaching statistical significance over the control at 100 and 150 cycles (22.6 mm se 2.5 versus 12.5 mm se 0.3; and 29.6 mm se 4.8 versus 17.0 mm se 0.7). Every all-suture anchor tested showed substantial (> 5 mm) displacement between 50 and 100 cycles (6.2 to 14.3).All-suture anchors predominantly failed due to anchor pull-out (95% versus 25% of traditional anchors), whereas a higher proportion of traditional anchors failed secondary to suture breakage. CONCLUSION: We demonstrate decreased failure load, increased total displacement, and variable failure mechanisms in all-suture anchors, compared with traditional anchors designed for rotator cuff repair. These findings will aid the surgeon's choice of implant, in the context of the clinical scenario.Cite this article: N. S. Nagra, N. Zargar, R. D. J. Smith, A. J. Carr. Mechanical properties of all-suture anchors for rotator cuff repair. Bone Joint Res 2017;6:82-89. DOI: 10.1302/2046-3758.62.BJR-2016-0225.R1.

8.
Nat Commun ; 7: 10491, 2016 Feb 03.
Article in English | MEDLINE | ID: mdl-26839155

ABSTRACT

Coral reefs are among the most species-rich and threatened ecosystems on Earth, yet the extent to which human stressors determine species occurrences, compared with biogeography or environmental conditions, remains largely unknown. With ever-increasing human-mediated disturbances on these ecosystems, an important question is not only how many species can inhabit local communities, but also which biological traits determine species that can persist (or not) above particular disturbance thresholds. Here we show that human pressure and seasonal climate variability are disproportionately and negatively associated with the occurrence of large-bodied and geographically small-ranging fishes within local coral reef communities. These species are 67% less likely to occur where human impact and temperature seasonality exceed critical thresholds, such as in the marine biodiversity hotspot: the Coral Triangle. Our results identify the most sensitive species and critical thresholds of human and climatic stressors, providing opportunity for targeted conservation intervention to prevent local extinctions.


Subject(s)
Biodiversity , Climate , Conservation of Natural Resources , Coral Reefs , Ecosystem , Fishes , Seasons , Animals , Body Size , Humans , Stress, Physiological , Temperature
9.
Eur Cell Mater ; 31: 107-18, 2016 Jan 27.
Article in English | MEDLINE | ID: mdl-26815643

ABSTRACT

Surgical repairs of rotator cuff tears have high re-tear rates and many scaffolds have been developed to augment the repair. Understanding the interaction between patients' cells and scaffolds is important for improving scaffold performance and tendon healing. In this in vitro study, we investigated the response of patient-derived tenocytes to eight different scaffolds. Tested scaffolds included X-Repair, Poly-Tape, LARS Ligament, BioFiber (synthetic scaffolds), BioFiber-CM (biosynthetic scaffold), GraftJacket, Permacol, and Conexa (biological scaffolds). Cell attachment, proliferation, gene expression, and morphology were assessed. After one day, more cells attached to synthetic scaffolds with dense, fine and aligned fibres (X-Repair and Poly-Tape). Despite low initial cell attachment, the human dermal scaffold (GraftJacket) promoted the greatest proliferation of cells over 13 days. Expression of collagen types I and III were upregulated in cells grown on non-cross-linked porcine dermis (Conexa). Interestingly, the ratio of collagen I to collagen III mRNA was lower on all dermal scaffolds compared to synthetic and biosynthetic scaffolds. These findings demonstrate significant differences in the response of patient-derived tendon cells to scaffolds that are routinely used for rotator cuff surgery. Synthetic scaffolds promoted increased cell adhesion and a tendon-like cellular phenotype, while biological scaffolds promoted cell proliferation and expression of collagen genes. However, no single scaffold was superior. Our results may help understand the way that patients' cells interact with scaffolds and guide the development of new scaffolds in the future.


Subject(s)
Orthopedic Procedures/methods , Tendon Injuries/surgery , Tendons/cytology , Tissue Scaffolds , Cell Adhesion/physiology , Cell Proliferation/physiology , Cells, Cultured , Collagen Type I/biosynthesis , Collagen Type I/genetics , Collagen Type III/biosynthesis , Collagen Type III/genetics , Humans , RNA, Messenger/genetics , Rotator Cuff/surgery , Rotator Cuff Injuries , Wound Healing/physiology
10.
Rev Sci Instrum ; 86(9): 094102, 2015 Sep.
Article in English | MEDLINE | ID: mdl-26429459

ABSTRACT

An Adaptable Multiple Power Source (AMPS) system has been designed and constructed. The AMPS system can provide up to 16 direct current (DC) (±400 V; 5 mA), 4 radio frequency (RF) (two 500 VPP sinusoidal signals each, 0.5-5 MHz) channels, 2 high voltage sources (±6 kV), and one ∼40 W, 250 °C temperature-regulated heater. The system is controlled by a microcontroller, capable of communicating with its front panel or a computer. It can assign not only pre-saved fixed DC and RF signals but also profiled DC voltages. The AMPS system is capable of driving many mass spectrometry components and ancillary devices and can be adapted to other instrumentation/engineering projects.


Subject(s)
Electric Power Supplies , Mass Spectrometry/instrumentation , Equipment Design , Fourier Analysis , Radio Waves
11.
Mar Pollut Bull ; 98(1-2): 201-9, 2015 Sep 15.
Article in English | MEDLINE | ID: mdl-26169226

ABSTRACT

Intensive fish culture in open sea pens delivers large amounts of nutrients to coastal environments. Relative to particulate waste impacts, the ecological impacts of dissolved wastes are poorly known despite their potential to substantially affect nutrient-assimilating components of surrounding ecosystems. Broad-scale enrichment effects of salmonid farms on Tasmanian reef communities were assessed by comparing macroalgal cover at four fixed distances from active fish farm leases across 44 sites. Macroalgal assemblages differed significantly between sites immediately adjacent (100m) to fish farms and reference sites at 5km distance, while sites at 400m and 1km exhibited intermediate characteristics. Epiphyte cover varied consistently with fish farm impacts in both sheltered and exposed locations. The green algae Chaetomorpha spp. predominated near fish farms at swell-exposed sites, whereas filamentous green algae showed elevated densities near sheltered farms. Cover of canopy-forming perennial algae appeared unaffected by fish farm impacts.


Subject(s)
Aquaculture/methods , Salmon , Animals , Anthozoa , Chlorophyta/physiology , Ecosystem , Environment , Oceans and Seas , Seaweed , Tasmania
13.
J Neurosurg Sci ; 59(1): 79-90, 2015 Mar.
Article in English | MEDLINE | ID: mdl-25387659

ABSTRACT

Spina bifida remains a challenging neurosurgical entity to manage despite both an increased awareness of the disease as well as a decreased incidence due to folic acid supplementation. We review the spectrum of neural tube defects, which are the second most common serious congenital defect and the most common of the central nervous system, and discuss the latest management paradigms. The challenges of timely diagnosis and treatment of spina bifida occulta and the latest advances in fetal repair of spina bifida aperta (myelomeningocele) will be discussed. The authors review the literature and share their experience with managing neural tube defects.


Subject(s)
Spina Bifida Occulta/diagnosis , Spina Bifida Occulta/surgery , Female , Fetal Diseases/surgery , Fetal Therapies/methods , Fetus/surgery , Humans , Pregnancy
14.
Nature ; 503(7476): 365-70, 2013 Nov 21.
Article in English | MEDLINE | ID: mdl-24226776

ABSTRACT

Chronic infections are difficult to treat with antibiotics but are caused primarily by drug-sensitive pathogens. Dormant persister cells that are tolerant to killing by antibiotics are responsible for this apparent paradox. Persisters are phenotypic variants of normal cells and pathways leading to dormancy are redundant, making it challenging to develop anti-persister compounds. Biofilms shield persisters from the immune system, suggesting that an antibiotic for treating a chronic infection should be able to eradicate the infection on its own. We reasoned that a compound capable of corrupting a target in dormant cells will kill persisters. The acyldepsipeptide antibiotic (ADEP4) has been shown to activate the ClpP protease, resulting in death of growing cells. Here we show that ADEP4-activated ClpP becomes a fairly nonspecific protease and kills persisters by degrading over 400 proteins, forcing cells to self-digest. Null mutants of clpP arise with high probability, but combining ADEP4 with rifampicin produced complete eradication of Staphylococcus aureus biofilms in vitro and in a mouse model of a chronic infection. Our findings indicate a general principle for killing dormant cells-activation and corruption of a target, rather than conventional inhibition. Eradication of a biofilm in an animal model by activating a protease suggests a realistic path towards developing therapies to treat chronic infections.


Subject(s)
Anti-Bacterial Agents/pharmacology , Biofilms/drug effects , Biofilms/growth & development , Proteolysis/drug effects , Serine Endopeptidases/metabolism , Staphylococcus aureus/drug effects , Staphylococcus aureus/enzymology , Animals , Bacterial Proteins/metabolism , Depsipeptides/pharmacology , Drug Resistance, Bacterial/drug effects , Enzyme Activation/drug effects , Female , Mice , Microbial Viability/drug effects , Proteomics , Rifampin/pharmacology , Staphylococcal Infections/drug therapy , Staphylococcal Infections/microbiology , Staphylococcus aureus/classification , Staphylococcus aureus/metabolism
15.
Clin Oncol (R Coll Radiol) ; 22(9): 733-9, 2010 Nov.
Article in English | MEDLINE | ID: mdl-20728326

ABSTRACT

Patients with malignant ureteric obstruction often have a poor life expectancy, even if relief of urinary obstruction is achieved. Careful discussion between the patient, their family and all health care professionals involved in the case must be undertaken before any intervention. The goal of treatment in the palliative setting may be to offer symptom relief, avoid complications from renal insufficiency or allow further oncological systemic therapy. The obstruction can be relieved by placement of a percutaneous nephrostomy tube, a ureteric stent or, more rarely, due to the palliative nature of the patients, a more complex open surgical procedure. Nephrostomy tubes offer excellent drainage and can be placed under a local anaesthetic, although they do require and a bag, which can reduce a patient's quality of life. Bleeding, sepsis, bowel transgression and pleural complications can all be encountered when inserting a nephrostomy. JJ stents in comparison have a higher failure rate due to extrinsic compression and usually require a general anaesthetic for placement, although significant bleeding and other complications are reduced. Quality of life is still affected by irritative lower urinary tract symptoms. Metallic ureteric stents have recently been developed to try and offer better relief of obstruction than polymeric stents with fewer side-effects and increased intervals between changes. Initial data appear encouraging, although further trials are needed. No blueprint for treatment of malignant ureteric obstruction exists and each case must be decided on an individual basis with a fully informed patient.


Subject(s)
Drainage/methods , Palliative Care , Stents , Ureter/surgery , Ureteral Obstruction/surgery , Humans , Neoplasms/complications , Nephrostomy, Percutaneous , Quality of Life , Ureteral Obstruction/etiology
16.
Ann Bot ; 105(6): 1035-52, 2010 Jun.
Article in English | MEDLINE | ID: mdl-20228084

ABSTRACT

BACKGROUND AND AIMS: Using two parental clones of outcrossing Trifolium ambiguum as a potential model system, we examined how during seed development the maternal parent, number of seeds per pod, seed position within the pod, and pod position within the inflorescence influenced individual seed fresh weight, dry weight, water content, germinability, desiccation tolerance, hardseededness, and subsequent longevity of individual seeds. METHODS: Near simultaneous, manual reciprocal crosses were carried out between clonal lines for two experiments. Infructescences were harvested at intervals during seed development. Each individual seed was weighed and then used to determine dry weight or one of the physiological behaviour traits. KEY RESULTS: Whilst population mass maturity was reached at 33-36 days after pollination (DAP), seed-to-seed variation in maximum seed dry weight, when it was achieved, and when maturation drying commenced, was considerable. Individual seeds acquired germinability between 14 and 44 DAP, desiccation tolerance between 30 and 40 DAP, and the capability to become hardseeded between 30 and 47 DAP. The time for viability to fall to 50 % (p(50)) at 60 % relative humidity and 45 degrees C increased between 36 and 56 DAP, when the seed coats of most individuals had become dark orange, but declined thereafter. Individual seed f. wt at harvest did not correlate with air-dry storage survival period. Analysing survival data for cohorts of seeds reduced the standard deviation of the normal distribution of seed deaths in time, but no sub-population showed complete uniformity of survival period. CONCLUSIONS: Variation in individual seed behaviours within a developing population is inherent and inevitable. In this outbreeder, there is significant variation in seed longevity which appears dependent on embryo genotype with little effect of maternal genotype or architectural factors.


Subject(s)
Coffea/radiation effects , Longevity/radiation effects , Seeds/drug effects , Seeds/physiology , Trifolium/radiation effects , Adaptation, Physiological/radiation effects , Cell Survival/radiation effects , Coffea/physiology , Desiccation/methods , Electron Spin Resonance Spectroscopy/methods , Seeds/growth & development , Temperature , Trifolium/growth & development
17.
Ann Bot ; 103(8): 1261-70, 2009 Jun.
Article in English | MEDLINE | ID: mdl-19304995

ABSTRACT

BACKGROUND AND AIMS: Most priming studies have been conducted on commercial seed lots of unspecified uniformity and maturity, and subsequent seed longevity has been reported to both increase and decrease. Here a seed lot of Digitalis purpurea L. with relatively uniform maturity and known history was used to analyse the effects of priming on seed longevity in air-dry storage. METHODS: Seeds collected close to natural dispersal and dried at 15% relative humidity (RH), 15 degrees C, were placed into experimental storage (60% RH, 45 degrees C) for 14 or 28 d, primed for 48 h at 0, -1, -2, -5, -10 or -15 MPa, re-equilibrated (47% RH, 20 degrees C) and then returned to storage. Further seed samples were primed for 2 or 48 h at -1 MPa and either dried at 15% RH, 15 degrees C or immediately re-equilibrated for experimental storage. Finally, some seeds were given up to three cycles of experimental storage and priming (48 h at -1 MPa). KEY RESULTS: Priming at -1 MPa had a variable effect on subsequent survival during experimental storage. The shortest lived seeds in the control population showed slightly increased life spans; the longer lived seeds showed reduced life spans. In contrast, seeds first stored for 14 or 28 d before priming had substantially increased life spans. The increase tended to be greatest in the shortest lived fraction of the seed population. Both the period of rehydration and the subsequent drying conditions had significant effects on longevity. Interrupting air-dry storage with additional cycles of priming also increased longevity. CONCLUSIONS: The extent of prior deterioration and the post-priming desiccation environment affect the benefits of priming to the subsequent survival of mature seeds. Rehydration-dehydration treatments may have potential as an adjunct or alternative to the regeneration of seed accessions maintained in gene banks for plant biodiversity conservation or plant breeding.


Subject(s)
Digitalis/embryology , Seeds , Germination
18.
Ann Bot ; 103(5): 785-94, 2009 Mar.
Article in English | MEDLINE | ID: mdl-19136494

ABSTRACT

BACKGROUND AND AIMS: Seed quality may be compromised if seeds are harvested before natural dispersal (shedding). It has been shown previously that slow or delayed drying can increase potential quality compared with immediate rapid drying. This study set out to investigate whether or not there is a critical moisture content, below which drying terminates maturation events for seeds harvested after mass maturity but before dispersal. METHODS: Seeds of foxglove (Digitalis purpurea) in the post-abscission pre-dispersal phase were held at between 15 and 95 % RH for 4 or 8 d, with or without re-hydration to 95 % RH for a further 4 d, before drying to equilibrium at 15 % RH. In addition, dry seeds were primed for 48 h at -1 MPa. Subsequent seed longevity was assessed at 60 % RH and 45 degrees C. KEY RESULTS: Rate of germination and longevity were improved by holding seeds at a wide range of humidities after harvest. Longevity was further improved by re-hydration at 95 % RH. Priming improved the longevity of the seeds dried immediately after harvest, but not of those first held at 95 % RH for 8 d prior to drying. CONCLUSIONS: Maturation continued ex planta in these post-abscission, pre-dispersal seeds of D. purpurea dried at 15-80 % RH at a rate correlated positively with RH (cf. ageing of mature seeds). Subsequent re-hydration at 95 % RH enabled a further improvement in quality. Priming seeds initially stored air-dry for 3 months also allowed maturation events to resume. However, once individual seeds within the population had reached maximum longevity, priming had a negative impact on their subsequent survival.


Subject(s)
Desiccation , Digitalis/growth & development , Digitalis/physiology , Seeds/growth & development , Seeds/physiology , Agriculture , Flowers/physiology , Germination , Temperature , Time Factors , Water/physiology
19.
IET Syst Biol ; 2(5): 222-33, 2008 Sep.
Article in English | MEDLINE | ID: mdl-19045818

ABSTRACT

One goal of systems biology is to understand how genome-encoded parts interact to produce quantitative phenotypes. The Alpha Project is a medium-scale, interdisciplinary systems biology effort that aims to achieve this goal by understanding fundamental quantitative behaviours of a prototypic signal transduction pathway, the yeast pheromone response system from Saccharomyces cerevisiae. The Alpha Project distinguishes itself from many other systems biology projects by studying a tightly bounded and well-characterised system that is easily modified by genetic means, and by focusing on deep understanding of a discrete number of important and accessible quantitative behaviours. During the project, the authors have developed tools to measure the appropriate data and develop models at appropriate levels of detail to study a number of these quantitative behaviours. The authors have also developed transportable experimental tools and conceptual frameworks for understanding other signalling systems. In particular, the authors have begun to interpret system behaviours and their underlying molecular mechanisms through the lens of information transmission, a principal function of signalling systems. The Alpha Project demonstrates that interdisciplinary studies that identify key quantitative behaviours and measure important quantities, in the context of well-articulated abstractions of system function and appropriate analytical frameworks, can lead to deeper biological understanding. The authors' experience may provide a productive template for systems biology investigations of other cellular systems.


Subject(s)
Models, Biological , Pheromones/metabolism , Proteome/metabolism , Research/trends , Saccharomyces cerevisiae Proteins/metabolism , Saccharomyces cerevisiae/metabolism , Signal Transduction/physiology , Computer Simulation , Protein Interaction Mapping/methods
20.
Health Econ ; 17(11): 1317-22, 2008 Nov.
Article in English | MEDLINE | ID: mdl-18246542

ABSTRACT

We argue that traditional health economic analysis is ill-equipped to estimate the cost effectiveness and cost benefit of interventions that aim at controlling and/or preventing public health emergencies of international concern (such as pandemic influenza or severe acute respiratory syndrome). The implicit assumption of partial equilibrium within both the health sector itself and--if a wider perspective is adopted--the economy as a whole would be violated by such emergencies. We propose an alternative, with the specific aim of accounting for the behavioural changes and capacity problems that are expected to occur when such an outbreak strikes.


Subject(s)
Disaster Planning/economics , Emergencies/economics , Public Health/economics , Cost-Benefit Analysis , Disaster Planning/methods , Disasters/economics , Disasters/prevention & control , Disease Outbreaks/economics , Disease Outbreaks/prevention & control , Global Health , Humans , Public Health Administration/economics , Public Health Administration/methods
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