374 research outputs found
Somatic embryogenesis from stem nodal sections of grapevine
Indirect somatic embryogenesis was obtained for 11 clones of 6 Vitis vinifera cultivars: Cabernet-Sauvignon, Chardonnay, Gewürztraminer, Grenache, Merlot and Sauvignon, and for the rootstock Fercal [(Vitis berlandieri x Vitis colombard) x (Vitis vinifera x Vitis berlandieri)], starting from vegetative explants of in vitro plantlets. Embryogenic callus was recovered from nodal explants of every tested clone, while leaf explants led to embryogenesis only for the rootstock Fercal. We thus showed that axillary bud microcuttings are valuable explants for inducing somatic embryogenesis in V. vinifera and Fercal. Embryogenic cell lines have been maintained through secondary embryogenesis, and some embryos were converted into whole plantlets. A complete protocol for somatic embryogenesis and plant regeneration was therefore designed, using this very simple method.
A progressive refinement approach for the visualisation of implicit surfaces
Visualising implicit surfaces with the ray casting method is a slow procedure. The design cycle of a new implicit surface is, therefore, fraught with long latency times as a user must wait for the surface to be rendered before being able to decide what changes should be introduced in the next iteration. In this paper, we present an attempt at reducing the design cycle of an implicit surface modeler by introducing a progressive refinement rendering approach to the visualisation of implicit surfaces. This progressive refinement renderer provides a quick previewing facility. It first displays a low quality estimate of what the final rendering is going to be and, as the computation progresses, increases the quality of this estimate at a steady rate. The progressive refinement algorithm is based on the adaptive subdivision of the viewing frustrum into smaller cells. An estimate for the variation of the implicit function inside each cell is obtained with an affine arithmetic range estimation technique. Overall, we show that our progressive refinement approach not only provides the user with visual feedback as the rendering advances but is also capable of completing the image faster than a conventional implicit surface rendering algorithm based on ray casting
Cryptosporidium Priming Is More Effective than Vaccine for Protection against Cryptosporidiosis in a Murine Protein Malnutrition Model
Cryptosporidium is a major cause of severe diarrhea, especially in malnourished children. Using a murine model of C. parvum oocyst challenge that recapitulates clinical features of severe cryptosporidiosis during malnutrition, we interrogated the effect of protein malnutrition (PM) on primary and secondary responses to C. parvum challenge, and tested the differential ability of mucosal priming strategies to overcome the PM-induced susceptibility. We determined that while PM fundamentally alters systemic and mucosal primary immune responses to Cryptosporidium, priming with C. parvum (106 oocysts) provides robust protective immunity against re-challenge despite ongoing PM. C. parvum priming restores mucosal Th1-type effectors (CD3+CD8+CD103+ T-cells) and cytokines (IFNγ, and IL12p40) that otherwise decrease with ongoing PM. Vaccination strategies with Cryptosporidium antigens expressed in the S. Typhi vector 908htr, however, do not enhance Th1-type responses to C. parvum challenge during PM, even though vaccination strongly boosts immunity in challenged fully nourished hosts. Remote non-specific exposures to the attenuated S. Typhi vector alone or the TLR9 agonist CpG ODN-1668 can partially attenuate C. parvum severity during PM, but neither as effectively as viable C. parvum priming. We conclude that although PM interferes with basal and vaccine-boosted immune responses to C. parvum, sustained reductions in disease severity are possible through mucosal activators of host defenses, and specifically C. parvum priming can elicit impressively robust Th1-type protective immunity despite ongoing protein malnutrition. These findings add insight into potential correlates of Cryptosporidium immunity and future vaccine strategies in malnourished children
The influence of detachment strength on the evolving deformational energy budget of physical accretionary prisms
Tracking the evolution of the deformational energy budget within accretionary
systems provides insight into the driving mechanisms that control fault
development. To quantify the impact of these mechanisms on overall system
efficiency, we estimate energy budget components as the first thrust fault
pair develops in dry-sand accretion experiments. We track energy budget
components in experiments that include and exclude a basal layer of glass
beads in order to investigate the influence of detachment strength on work
partitioning. We use the measurements of normal force exerted on the backwall
to estimate external work, and measurements of strain observed on the sides
of the sand packs to estimate the internal work, frictional work and work
against gravity done within increments of each experiment. Thrust fault
development reduces the incremental external work and incremental internal
work, and increases the incremental frictional work and incremental
gravitational work. The faults that develop within higher-friction detachment
experiments produce greater frictional work than the faults in experiments
with glass bead detachments because the slip distribution along the
detachments remains the same, while the effective friction coefficient of the
detachment differs between the experiments. The imbalance of the cumulative
work budget suggests that additional deformational processes that are not
fully captured in our measurements of the energy budget, such as acoustic
energy, consume work within the deforming wedge.</p
Prediction of thrusting sequence based on maximum rock strength and sandbox validation
This research aims to develop and validate simple procedures, accounting for mechanical equilibrium and maximum rock strength, to select the dominant mode of folding and to predict sequences of thrusting in fold-and-thrust belts and accretionary wedges. An inverse analysis of sandbox experiments is proposed to validate the procedures, leading to an estimation of the fault strength from the position, and the lifetime of the first thrust. The statistics of experimental uncertainties is constructed to obtain probability distributions of the friction parameters. The procedure will be applied to a real field case: the Agrio fold-and-thrust belt, Neuquén basin, Argentina
Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study
Background: Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world.
Methods: This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the GlobalSurg 1 study and other studies that have been found to affect the likelihood of SSI were entered into risk adjustment models. The primary outcome measure was the 30-day SSI incidence (defined by US Centers for Disease Control and Prevention criteria for superficial and deep incisional SSI). Relationships with explanatory variables were examined using Bayesian multilevel logistic regression models. This trial is registered with ClinicalTrials.gov, number NCT02662231.
Findings: Between Jan 4, 2016, and July 31, 2016, 13 265 records were submitted for analysis. 12 539 patients from 343 hospitals in 66 countries were included. 7339 (58·5%) patient were from high-HDI countries (193 hospitals in 30 countries), 3918 (31·2%) patients were from middle-HDI countries (82 hospitals in 18 countries), and 1282 (10·2%) patients were from low-HDI countries (68 hospitals in 18 countries). In total, 1538 (12·3%) patients had SSI within 30 days of surgery. The incidence of SSI varied between countries with high (691 [9·4%] of 7339 patients), middle (549 [14·0%] of 3918 patients), and low (298 [23·2%] of 1282) HDI (p < 0·001). The highest SSI incidence in each HDI group was after dirty surgery (102 [17·8%] of 574 patients in high-HDI countries; 74 [31·4%] of 236 patients in middle-HDI countries; 72 [39·8%] of 181 patients in low-HDI countries). Following risk factor adjustment, patients in low-HDI countries were at greatest risk of SSI (adjusted odds ratio 1·60, 95% credible interval 1·05–2·37; p=0·030). 132 (21·6%) of 610 patients with an SSI and a microbiology culture result had an infection that was resistant to the prophylactic antibiotic used. Resistant infections were detected in 49 (16·6%) of 295 patients in high-HDI countries, in 37 (19·8%) of 187 patients in middle-HDI countries, and in 46 (35·9%) of 128 patients in low-HDI countries (p < 0·001).
Interpretation: Countries with a low HDI carry a disproportionately greater burden of SSI than countries with a middle or high HDI and might have higher rates of antibiotic resistance. In view of WHO recommendations on SSI prevention that highlight the absence of high-quality interventional research, urgent, pragmatic, randomised trials based in LMICs are needed to assess measures aiming to reduce this preventable complication
Meta-analysis of bone mineral density in adults with phenylketonuria
© 2024. The Author(s).BACKGROUND: Lifelong management of phenylketonuria (PKU) centers on medical nutrition therapy, including dietary phenylalanine (Phe) restriction in addition to Phe-free or low-Phe medical foods/protein substitutes. Studies have reported low bone mineral density (BMD) in mixed-age PKU populations, possibly related to long-term Phe restriction. Therefore, a meta-analysis investigating BMD specifically in adults with PKU was conducted. METHODS: Studies reporting BMD-related outcomes were identified from a systematic literature review evaluating somatic comorbidities experienced by adults with PKU on a Phe-restricted diet (searched February 1, 2022, updated November 1, 2023). Risk of study bias was assessed (Scottish Intercollegiate Guidelines Network checklists). The primary outcome of the meta-analysis was pooled mean BMD Z-scores of different bones. Secondary outcomes were the prevalence of low BMD Z-scores at pre-specified thresholds. Subgroup analyses of mean BMD Z-scores (decade of study publication, controlled versus uncontrolled blood Phe levels, gender) were conducted. RESULTS: BMD-related data from 4097 individuals across 10 studies rated as at least acceptable quality were included. Mean BMD Z-scores were statistically significantly lower compared with an age-matched control or reference (non-PKU) population, across bones, but still within the expected range for age (> -2.0): lumbar spine (seven studies, n = 304), -0.63 (95% confidence interval (CI): -0.74, -0.52); femoral neck (four studies, n = 170), -0.74 (95% CI: -1.25, -0.22); radius (three studies, n = 114), -0.77 (95% CI: -1.21, -0.32); total body (four studies, n = 157), -0.61 (95% CI: -0.77, -0.45). The small number of observations in the subgroup analyses resulted in a high degree of uncertainty, limiting interpretation. Estimated prevalence of BMD Z-scores ≤ -2.0 was 8% (95% CI: 5%, 13%; four studies, n = 221) and < -1.0 was 42% (95% CI: 35%, 51%; five studies, n = 144). CONCLUSIONS: Adults with PKU had lower BMD Z-scores than the reference (non-PKU) population but < 1 in 10 were below the expected range for age. The low number of studies prevents identification of which population characteristics are most impacting BMD. This meta-analysis was supported by BioMarin Pharmaceutical Inc., Novato, CA and is registered with the Research Registry (reviewregistry1476).publishersversionpublishe
Systematic literature review of the somatic comorbidities experienced by adults with phenylketonuria
Publisher Copyright: © The Author(s) 2024.Background: Phenylketonuria (PKU) is an inborn error of phenylalanine (Phe) metabolism that, if untreated, causes Phe accumulation in the brain leading to neurophysiologic alterations and poor outcomes. Lifelong management centers on dietary Phe restriction, yet long-term complete metabolic control is unachievable for many adults. High blood Phe levels or chronic Phe and intact protein restriction in the diet may lead to somatic comorbidities. A systematic literature review was conducted to evaluate somatic comorbidities experienced by adults with PKU. Methods: Clinical and observational studies reporting somatic comorbidities experienced by individuals with PKU aged ≥ 16 years (or classified as adults) evaluating a Phe-restricted diet with or without pharmacologic therapy versus no therapeutic intervention (including healthy controls), or pharmacologic therapy versus a Phe-restricted diet alone, were identified. PubMed® was searched (February 1, 2022 and updated November 1, 2023), using a pre-defined search strategy, followed by two-stage screening and data extraction. Included studies were grouped by PKU population comparison. Results: 1185 records were screened; 51 studies across 12,602 individuals were extracted. Bone-related abnormalities were the most reported outcome (n = 21); several outcome measures were used. Original study groupings included: Phe-restricted diet versus healthy controls or reference values (n = 40); treatment-adherent versus those non-adherent (n = 12). Additional groups added as part of a protocol amendment included: different Phe-restricted diets (n = 4); severe versus less severe disease (n = 5). Vote counting indicated a higher burden of ≥ 1 comorbidity (or outcome measure) for the Phe-restricted diet group by 37 of 38 studies included in the analysis of Phe-restricted diet versus healthy controls; higher burden in healthy controls was reported in 12 studies. Vote counting was similar between those treatment adherent (n = 7) versus non-adherent (n = 10). Conclusions: Adults with PKU have a higher comorbidity burden than a non-PKU population. More robust studies are needed to better understand the relationship between effective metabolic control and comorbidity burden, using consistent outcome measures. This SLR was supported by BioMarin Pharmaceutical Inc., Novato, CA, and is registered with the Research Registry (reviewregistry1476).publishersversionpublishe
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