220861 research outputs found
Sort by
Coupled X-ray imaging/diffraction reveals soil mechanics during analogous root growth.
No full textSoil compaction and escalating global drought increase soil strength and stiffness. It remains unclear which plant root biomechanical mechanisms/traits enable growth in these harsh conditions. Here, we combine synchrotron X-ray computed tomography with spatially resolved X-ray diffraction to characterize the biomechanics of a replica root-soil system. Wemap the strain field around the root tip analog, finding strong agreement with finite element simulations, thereby demonstrating a promising new in vivo measurement protocol.James Le Houx, Daniel McKay Fletcher, Alberto Leonardi, Katherine A. Williams, Nancy Walker, Fernando Alvarez-Borges, Ebrahim Afsar Dizaj, Madhu Murthy, Ronan Smith, Liam Perera, Navid Aslani, Andrew James, Sharif Ahmed, Tiina Roose, Siul Rui
Acute decrease in the plasma tryptophan-to-large-neutral-amino-acids ratio attenuates the effects of L-tryptophan on gut hormones and energy intake in healthy males: a randomized, cross-over, exploratory trial
No full textBackground L-tryptophan (“Trp”) and L-leucine (“Leu”), when administered intraduodenally, increase plasma cholecystokinin (CCK) and glucagon-like peptide 1 (GLP-1) and stimulate pyloric pressures, which all slow gastric emptying and suppress subsequent energy intake. The circulating Trp-to-large-neutral-amino-acids (“Trp/LNAAs”) ratio is also inversely related to energy intake. Objectives This exploratory study characterized the impact of standardized changes in the plasma Trp/LNAAs ratio, achieved by combining a fixed-load intraduodenal infusion of Trp with increasing loads of Leu, on the appetite-inhibitory effects of enteral Trp. Methods Twelve males of normal weight [mean ± standard deviation; age: 23 ± 2 y; body mass index (in kg/m²: 23±1)], received on 4 separate occasions, 90-min iso-osmotic intraduodenal infusions of 1) isotonic 0.9% saline (“control”), 2) Trp (0.15 kcal/min; “Trp”), 3) Trp + Leu (0.22 kcal/min; “Trp+Leu–0.22”), or 4) Trp + Leu (0.45 kcal/min; “Trp+Leu–0.45”), in a randomized, double-blind, cross-over fashion. Immediately postinfusion ad-libitum energy intake was quantified. Plasma CCK, GLP-1, amino acid concentrations, and antropyloroduodenal pressures were measured throughout. Results Although there was a transient stimulation of CCK and GLP-1 by Trp + Leu – 0.45 (at t = 15 min), only Trp led to a sustained increase in plasma CCK (P = 0.04) and GLP-1 (P = 0.009) from t = 60–90 min, and stimulated pyloric pressures (P = 0.01), compared with control. Only Trp reduced energy intake [kcal (mean ± standard error of the mean); control: 1085 ± 49, Trp: 881 ± 75, Trp + Leu – 0.22: 963 ± 57, Trp + Leu – 0.45: 932 ± 60] compared with control (P = 0.008). The Trp/LNAAs ratio was dose-dependently decreased by Trp + Leu – 0.22 and Trp + Leu – 0.45, compared with Trp (all P = 0.001), and energy intake correlated inversely with the Trp/LNAAs ratio (R = –0.38; P = 0.02). Conclusions Acute reduction in the Trp/LNAAs ratio appears to be associated with a diminished capacity of Trp to stimulate CCK and GLP-1 and suppress energy intake. Although these observations should be interpreted with caution given the exploratory nature of the study, they attest to the complexity of the relationships between pre and postabsorptive mechanisms underlying Trp’s appetite-inhibitory effect.Javad Anjom-Shoae, Maryam Hajishafiee, Penelope CE Fitzgerald, Rosie Coleman, Alyce M Martin, Sally D Poppitt, Michelle Lee, Suzanne Higgs, Jens F Rehfeld, Jens J Holst, Simon Veedfald, Michael Horowitz, Christine Feinle-Bisse
Inhibitors of lysine biosynthesis enzymes as potential new herbicides
No full textLysine is an amino acid that is essential for the growth and development of all organisms owing to its role in a plethora of critical biological functions and reactions. In plants, lysine is synthesised via five sequential enzyme-catalysed reactions collectively known as the diaminopimelate (DAP) pathway, whereas animals are reliant on their plant dietary intake to obtain lysine. Given that lysine is one of the most nutritionally limiting amino acids, several studies have focused on developing strategies to modulate the activity of DAP pathway enzymes to improve the nutritional value of crops. More recently, research has emerged on the potential of inhibiting DAP pathway enzymes for the development of herbicides with a novel mode of action. Over reliance on a small number of modes of action has led to a herbicide resistance crisis, necessitating the development of new modes of action to which no resistance exists. As such, the first herbicidal inhibitors of the DAP pathway have been developed, which target the first three enzymes in lysine biosynthesis. This review explores the structure, function, and inhibition of these enzymes, as well as highlighting promising avenues for the future development of new plant lysine biosynthesis inhibitors.Emily R. R. Mackie, Mirrin V. McKay, Andrew S. Barrow, and Tatiana P. Soares da Cost
Cost-effectiveness of atraumatic restorative treatment combined with the Hall Technique for managing dental caries in remote Indigenous children
No full textFirst published: 14 March 2025Background Indigenous children in remote Australia face significant disparities in oral health and have limited access to dental care. This study evaluated the cost-effectiveness of Atraumatic Restorative Treatment combined with the Hall Technique (ART-HT) compared to usual care. Methods A cost-effectiveness analysis using data from a 1-year ART-HT trial estimated dental caries status and costs from a health-provider perspective. Two scenarios were examined: (1) actual treatment costs and (2) minimum dental services. The incremental cost per decayed, missing, and filled teeth (dmft) prevented was calculated in AUD 2021 prices. A probabilistic sensitivity analysis was conducted. Results Among 228 children (ART-HT = 122; usual care = 106), deterministic analysis showed ART-HT required additional costs of 72.37 for scenarios 1 and 2, with 0.90 dmft prevented. Probabilistic sensitivity analysis revealed ART-HT resulted in better oral health outcomes with a mean dmft prevented of 0.58 (95% uncertainty interval: 0.09 to1.07). The mean additional cost per dmft prevented was 181.84 for scenarios 1 and 2. Conclusions ART-HT effectively managed dental caries in Indigenous children, providing better oral health outcomes compared to usual care, albeit with modest additional costs. This approach may improve access to culturally appropriate dental care in remote communities.U Tonmukayakul, S Kularatna, S Piggott, D Atkinson, D Brennan, L Jamieson, P Arro
Early clinical evaluation of the Hugo robotic-assisted surgery (RAS) for performing radical prostatectomy: an IDEAL stage 2 study
No full textObjectives: To assess the feasibility and safety of the new Hugo robotic-assisted surgery (RAS) system for robotic-assisted radical prostatectomy (RARP), describing iterative changes in our operative technique—IDEAL stage 2. Design: Prospective, single-centre series. Setting: Tertiary urological unit in London, UK. Participants: Male patients diagnosed with clinically localised prostate cancer and suitable for RARP from February 2023 to May 2024. Main outcome measures: The primary outcome was to assess the safety of using the device without converting to the existing robotic platform (da Vinci), laparoscopy or open. Secondary outcomes assessed surgical (operative time, blood loss, time to catheter removal, complications), oncologic (surgical pathology and margin status) and early functional (continence) outcomes. Results: 50 patients were included in the study. No cases required conversion to an existing robotic platform, laparoscopy or open, and there were no intraoperative surgical complications. Mean age was 60 years and mean prostate-specific antigen was 12.2 ng/mL. The mean operative time was 148 min and estimated blood loss was 168 mL. Mean length of stay was 1.5 days and mean length of catheter duration was 13 days. On final pathology, 18 patients (36%) had T3 disease and four had positive surgical margins (8%). The mean International Consultation on Incontinence Questionnaire–Urinary Incontinence score for urinary continence at 3 months was 7. There were six Clavien-Dindo grade 2 complications and two Clavien-Dindo 3a complications. There were four instances of recoverable, temporary device failure. Iterative improvements were made to docking setup, use of robotic instruments and reduction in robotic arm collisions. Conclusions: We demonstrated feasibility and the safe introduction of the Hugo RAS for RARP into an experienced robotic urological programme. Perioperative, early oncological and functional outcomes were similar to other early series. Further studies will aim to describe the learning curve with this robot and optimisation of surgical quality.Andrew Shepherd, Ata Jaffer, Angus Bruce, Daniel Chia, Prokar Dasgupta, Ben Challacomb
Accidental and Regulated Cell Death in Yeast Colony Biofilms
No full textThe yeast species Saccharomyces cerevisiae is one of the most intensively studied organisms on the planet due to it being an excellent eukaryotic model organism in molecular and cell biology. In this work, we investigate the growth and morphology of yeast colony biofilms, where proliferating yeast cells reside within a self-produced extracellular matrix. This research area has garnered significant scientific interest due to its applicability in the biological and biomedical sectors. A central feature of yeast colony biofilm expansion is cellular demise, which is onset by one of two independent mechanisms: either accidental cell death (ACD) or regulated cell death (RCD). In this article, we generalise a continuum model for the nutrient-limited growth of a yeast colony biofilm to include the effects of ACD and RCD. This new model involves a system of four coupled nonlinear reaction-diffusion equations for the yeast-cell density, the nutrient concentration, and two species of dead cells. Numerical solutions of the spatially one and two-dimensional governing equations reveal the impact that ACD and RCD have on expansion speed, morphology and cell distribution within the colony biofilm. Our results are in good qualitative agreement with our own experiments.Daniel J. Netherwood, Alexander K. Y. Tam, Campbell W. Gourlay, Tea Kneževic, Jennifer M. Gardner, Vladimir Jiranek, Benjamin J. Binder, J. Edward F. Gree
Transport of animals underpinned ritual feasting at the onset of the Neolithic in southwestern Asia
No full textFeasting played an important role in cementing social bonds between prehistoric communities. At Early Neolithic Asiab, western Iran, ceremonial feasting is evidenced by the butchered skulls of nineteen wild boars (Sus scrofa), an animal that was not commonly hunted in the region at the time. Here we use microscopic dental growth patterns to guide geochemical analyses of five wild boar teeth from Asiab and examine the geographical scope from which the animals derived. Our dataset includes 165 stable oxygen isotope values, 107 strontiumisotope ratios, and Barium concentration maps. The findings indicate that despite Asiab’s location in an environment favourable to wild boars, the animals used for ceremonial feasting originated from a wide geographical catchment, with at least some necessitating transport over substantial distance across mountainous terrain. This deepens our understanding of the effort invested by the participating pre-agricultural communities for celebrating social connectivity across the wider landscape.Petra Vaiglova, Horst Kierdorf, Carsten Witzel, Georgina Falster, Renaud Joannes-Boyau, Yue Wang, Jiade Wu, Ian Williams, Brett Knowles, Yang Wu, Pernille Bangsgaard, Lisa Yeomans, Tobias Richter, Hojjat Darab
2,4-D resistance due to a deletion in IAA2 in Sisymbrium orientale L. carries no apparent fitness penalty
No full textBACKGROUND: A deletion mutation in the degron tail of auxin coreceptor IAA2 was found to confer resistance to the herbicide 2,4-D in Sisymbrium orientale. Given the importance of auxin signalling in plant development, this study was conducted to investigate whether this deletion mutation may affect plant fitness. RESULTS: The F2 progeny of crosses with two resistant populations P2 (P2♂ × S♀) and P13 (P13♂ × S♀) were used in this study. The F2 plants were grown under competition with wheat in pot-trials and evaluated for biomass and total seed production. Progeny of the F2 plants were phenotyped by application of 250 g a.e. ha-1 2,4-D and genotyped for the 27 bp deletion in IAA2. In a separate experiment, F4 and F5 recombinant inbred lines (RILs) with resistant and susceptible phenotypes were grown in monoculture and phenotyped over time for biomass and seed production. Wheat competition reduced biomass and seed production for all genotypes in each population and in each year. A density of 400 plants m-2 of wheat reduced Sisymbrium orientale biomass by 76-78% in 2016 and by 59-63% in 2017 and total seed production by 80-83% and 60-64% by respective year. For the experiment involving resistant and susceptible RILs, biomass accumulation and seed production were the same between resistant and susceptible for both populations. CONCLUSIONS: The 27 bp deletion in IAA2 in Sisymbrium orientale does not carry a measurable fitness penalty, as determined by biomass reduction or seed production, either in monoculture or in competition with wheat. As a result, this mutation is unlikely to decrease over time in weed populations if 2,4-D selection pressure were removed. © 2025 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.Jenna M Malone, Hue Thi Dang, Marcelo RA de Figueiredo, Gurjeet Gill, Todd A Gaines and Christopher Presto
Thermoregulation in response to heat stress in sheep and impacts on fertility
No full textHeat stress presents a major challenge to the sustainability of the Australian sheep industry. Although controlled studies have demonstrated its adverse effects on the fertility of ewes and rams, as well as on early embryonic and fetal development, the impact of heat stress under extensive grazing conditions remains poorly understood. Furthermore, the role of individual variation in thermal thresholds and its influence on reproductive performance and productivity has not yet been defined. This thesis aimed to quantify heat stress at the individual animal level and investigate its relationship with reproductive outcomes and behaviour in grazing sheep. The objectives of the first two chapters (Chapters 1 and 2) were to: (1) review the effects of heat stress on sheep productivity, and (2) evaluate technologies for the automated collection of heat stress data in sheep. Chapter 3 aimed to design and validate a minimally invasive, indwelling, and automated method for monitoring core body temperature in ewes. Vaginal temperature proved to be a reliable indicator of true core temperature under intensive conditions, showing a sound correlation with rectal temperature. This study also demonstrated that the handling and restraint required for manual rectal measurements induced stress-related hyperthermia, potentially confounding subsequent assessments of core temperature. Chapter 4 classified ewes based on individual thermal thresholds under grazing conditions and evaluated associations between heat stress responses, reproductive outcomes, behaviour, and lamb growth. Continuous vaginal temperature measurements showed greater repeatability during hot conditions, particularly among high-responding ewes. High-responding individuals exceeded their normal temperature range at lower ambient temperatures, travelled greater distances, and were in lower body condition during early gestation. Although there were no significant differences in measures of reproductive output between groups, these findings highlights the complexity of assessing heat stress effects under extensive field conditions, where multiple environmental and animal-level factors interact. These findings reinforce the challenges of detecting clear physiological signals in real-world settings, even when using continuous, high-resolution temperature data. The final study (Chapter 5) examined axillary and scrotal thermoregulation in rams and its association with male fertility traits under grazing conditions. This study assessed the capacity of juvenile Merino rams to maintain thermal homeostasis during summer and explored relationships with semen quality, as well as maternal thermal tolerance. Rams with superior scrotal thermoregulation displayed some improved semen characteristics, and maternal heat tolerance was associated with enhanced thermoregulatory capacity in offspring. Consistent with findings in ewes, repeatability of both scrotal and axillary temperature was higher under hot conditions and significantly greater in high-responding individuals. In conclusion, low and high-responding animals can be identified under grazing conditions with sound repeatability. Individual ability to regulate body temperature under heat load has partial flow-on effects to behavioural decisions and reproductive outcomes. Additionally, some transgenerational patterns indicate the potential in incorporating thermoregulatory traits into breeding programs and developing management strategies to enhance heat resilience in sheep, thereby supporting the industry's sustainability amid changing climatic condition. Future research should further refine individual temperature thresholds, exploring genetic resilience, and leverage long-term sensor data to inform adaptive management of heat stress.Thesis (Ph.D.) -- University of Adelaide, School of Animal and Veterinary Sciences, 202
Caregiving experience of family caregivers for people with colorectal cancer: a qualitative systematic review protocol.
No full textObjective: This review aims to synthesize the most robust evidence regarding family caregivers’ experiences of caring for people with colorectal cancer. Introduction: Caring for people with colorectal cancer places a significant burden on caregivers that can affect their physical and psychological well-being. Understanding the unique experiences of family caregivers is essential for developing effective support systems that enhance their well-being. Eligibility criteria: This review will consider studies exploring the experiences of family caregivers caring for people with primary colorectal cancer. The studies will focus on qualitative data, including designs such as phenomenology, grounded theory, ethnography, qualitative descriptive studies, action research, feminist research, mixed methods studies, and program evaluations with embedded qualitative data. Methods: The review will follow the JBI methodology for systematic reviews of qualitative evidence. The search strategy will aim to locate published and unpublished studies, with no date or language restrictions. PubMed, CINAHL (EBSCOhost),Webof Science Core Collection, PsycINFO (EBSCOhost), Scopus, China National Knowledge Infrastructure, and Wanfang databases will be searched. The search for gray literature will include Google Scholar and ProQuest Dissertations and Theses. Two reviewers will independently select the studies, extract data, and critically appraise the methodological quality of the studies using the JBI critical appraisal checklist for qualitative research. The findings will be pooled using the meta-aggregation approach or presented in narrative format. The final synthesized findings will be graded for certainty according to the ConQual approach. Review registration: PROSPERO CRD42024517472Meng Liu, Nantaporn Sansiriphun, Warawan Udomkhwamsuk, Craig Lockwood, Patraporn Bhatarasakoo