62880 research outputs found
Sort by
Dynamic and structural insights into hydrogen-bonded interpolymer complexes of poly(2-alkyl-2-oxazolines) with poly(carboxylic acids)
Get PDFThe formation of interpolymer complexes (IPCs) between poly(2-alkyl-2-oxazolines) (PAOx) and poly(methacrylic acid) (PMAA) in solutions has been investigated using polarized luminescence relaxation and small-angle X-ray scattering (SAXS) structural methods. The results reveal that hydrophobic interactions contribute to the formation of IPCs in both aqueous and methanol solutions, influenced by the length of the side group in PAOx. The relaxation times, which can be used to quantify the intramolecular mobility of the luminescently labeled poly(methacrylic acid) (PMAA*), increase from 80 to 680 ns, indicating the formation of IPCs between PMAA* and PAOx. SAXS analysis of aqueous IPC solutions unveils their supramolecular organization, which is similar to that of nanohydrogels, with the hierarchical level comprising compact structures ranging from 4 to 10.7 nm in size
Phylogenetically informed predictions outperform predictive equations in real and simulated data
Get PDFInferring unknown trait values is ubiquitous across biological sciences—whether for reconstructing the past, imputing missing values for further analysis, or understanding evolution. Models explicitly incorporating shared ancestry amongst species with both known and unknown values (phylogenetically informed prediction) provide accurate reconstructions. However, 25 years after the introduction of such models, it remains common practice to simply use predictive equations derived from phylogenetic generalised least squares or ordinary least squares regression models to calculate unknown values. Here, we use a comprehensive set of simulations to demonstrate two- to three-fold improvement in the performance of phylogenetically informed predictions compared to both ordinary least squares and phylogenetic generalised least squares predictive equations. We found that phylogenetically informed prediction using the relationship between two weakly correlated (r = 0.25) traits was roughly equivalent to (or even better than) predictive equations for strongly correlated traits (r = 0.75). A critique and comparison of four published predictive analyses showcase real-world examples of phylogenetically informed prediction. We also highlight the importance of prediction intervals, which increase with increasing phylogenetic branch length. Finally, we offer guidelines to making phylogenetically informed predictions across diverse fields such as ecology, epidemiology, evolution, oncology, and palaeontology
Gut microbiota-targeted dietary supplementation with fermentable fibers and polyphenols prevents hypobaric hypoxia-induced increases in intestinal permeability
Get PDFInteractions between the gut microbiota and intestinal barrier may contribute to the pathophysiology of high-altitude illnesses. This study aimed to determine the effects of targeting the gut microbiota using dietary supplementation with a blend of fermentable fibers and polyphenol sources on gut microbiota composition, fecal short-chain fatty acids (SCFA) and intestinal function and permeability during hypobaric hypoxia exposure. Healthy adults participated in a randomized, double-blind, crossover study. Food products containing oligofructose-enriched inulin, galacto-oligosaccharide, high-amylose corn starch, cocoa, green tea and cranberry extracts and blueberry powder (FP) or maltodextrin (placebo; PL) were consumed daily during three 2wk phases separated by a ≥1wk washout. During the final 36hr of each phase participants resided in a hypobaric chamber simulating low (LA; 500m) or high (HA; 4300m) altitude creating three experimental conditions: PL+LA, PL+HA, FP+HA. Twenty-six participants completed ≥1 study phase and 13 (12 male; 21±3yr; BMI 25.4±2.4kg/m2) completed all three phases. Results demonstrated that FP mitigated hypoxia-induced increases in intestinal permeability within the small intestine and proximal colon while increasing Bifidobacterium relative abundance and decreasing gut microbiota α-diversity and colonic pH. Higher Bifidobacterium relative abundance and lower colonic pH were associated with greater reductions in intestinal permeability. However, FP did not alter fecal SCFA concentrations and increased gastrointestinal symptoms and altitude sickness during hypobaric hypoxia exposure. Findings suggest that targeting the gut microbiota with a combination of fermentable fibers and polyphenols can prevent hypobaric hypoxia-induced increases in intestinal permeability, but that benefit does translate into a reduction in altitude illness symptoms
Factors influencing the willingness to pay for wetland bird protection: a value assessment based on a questionnaire survey of residents in Gahai Wetland, Gansu, China
Get PDFThe Gahai wetland in Gansu, China, is a key wetland for nationally and globally threatened bird species. This research aims to quantify the economic value of wetland birds by the method of contingent valuation questionnaire, thereby providing a foundation for conservation of avian species. The result indicated that residents were willing to pay between 208 and 230 CNY (29–32 USD ). Men, locals, and older individuals were more inclined to contribute and offered higher payments, albeit non-significant correlation between education level and annual income with the willingness to pay. While the depth of understanding of wetland pressures did not significantly influence the willingness to pay, it did show a positive correlation; those with more profound understanding tended to be more generous in their payments. Tibetan male residents were more likely to prioritize ecological and environmental protection due to their religious beliefs and cultural customs, which emphasize the reverence for and compassion towards birds. This research not only complemented and validated the applicability of the contingent valuation method in China but also underscores the considerations that should be taken into account when employing this method
Intraseasonal linkages of winter surface air temperature between Eurasia and North America
Get PDFWintertime temperature extremes sometimes show a continental linkage between Eurasia and North America (NA), but whether these connections are coincidental or dynamically robust remains unclear. This study investigates the linkages of the leading intraseasonal temperature patterns between Eurasia and NA, focusing on the underlying dynamic processes. Our findings reveal a weak but robust linkage between the dominant patterns in both regions. Specifically, an opposite-phase temperature anomaly in NA occurs about 1 week after a Eurasian temperature anomaly, influenced by wave propagation in both the troposphere and stratosphere. Conversely, a same-phase temperature anomaly appears over central Eurasia approximately 1 week after a North American temperature anomaly, primarily driven by a Scandinavian-like pattern in the troposphere. These relationships sometimes overlap, forming a sequence of temperature changes across mid-high latitudes, closely tied to the stratosphere-troposphere coupling process. The findings provide new insights for a more comprehensive understanding of wintertime intraseasonal temperature variability
Online consumer research: more attention needs to be given to data quality
No full textThis manuscript aims to raise awareness of the need for Sensory & Consumer Science professionals to be more diligent about data quality control when conducting consumer surveys and experiments online. This aim is achieved by i) summarising recent research on data quality by Jaeger and Cardello (2022) and Castura et al. (2023), ii) contributing to a broader understanding of data quality, and iii) recommending a more systematic adoption of practices aimed to enhance data quality in online consumer research. Various suggestions are put forward to support Sensory & Consumer Science professionals who wish to pay greater attention to the quality of online data collection. We advocate for making online consumer data quality an integral part of the research process to improve the validity and reliability of research outcomes, ultimately benefiting the final users, including science, industry, and policymakers
Response adaptive randomisation in clinical trials: current practice, gaps and future directions
Get PDFIntroduction: Adaptive designs (ADs) offer clinical trials flexibility to modify design aspects based on accumulating interim data. Response adaptive randomisation (RAR) adjusts treatment allocation according to interim results, favouring promising treatments. Despite scientific appeal, RAR adoption lags behind other ADs. Understanding methods and applications could provide insights and resources and reveal future research needs. This study examines RAR application, trial results and achieved benefits, reporting gaps, statistical tools and concerns, while highlighting examples of effective practices. Methods: RAR trials with comparative efficacy, effectiveness or safety objectives, classified at least phase I/II, were identified via statistical literature, trial registries, statistical resources and researcher-knowledge. Search spanned until October 2023, including results until February 2024. Analysis was descriptive and narrative. Results: From 652 articles/trials screened, 65 planned RAR trials (11 platform trials) were identified, beginning in 1985 and gradually increasing through to 2023. Most trials were in oncology (25%) and drug-treatments (80%), with 63% led by US teams. Predominantly Phase II (62%) and multi-arm (63%), 85% used Bayesian methods, testing superiority hypotheses (86%). Binary outcomes appeared in 55%, with a median observation of 56 days. Bayesian RAR algorithms were applied in 83%. However, 71% of all trials lacked clear details on statistical implementation. Subgroup-level RAR was seen in 23% of trials. Allocation was restricted in 51%, and 88% was included a burn-in period. Most trials (85%) planned RAR alongside other adaptations. Of trials with results, 92% used RAR, but over 50% inadequately reported allocation changes. A mean 22% reduction in sample size was seen, with none over-allocating to ineffective arms. Conclusion: RAR has shown benefits in conditions like sepsis, COVID-19 and cancer, enhancing effective treatment allocation and saving resources. However, complexity, costs and simulation need limit wider adoption. This review highlights RAR's benefits and suggests enhancing statistical tools to encourage wider adoption in clinical research
Association between empirically driven dietary patterns and cardiometabolic disease risk factors: a cross-sectional analysis in disease-free adults
Get PDFBackground: Although links between dietary patterns (DPs) and cardiometabolic disease (CMD) risk markers have been identified in UK populations, these studies often rely on less quantitative measures of dietary assessment and include only a limited number of risk markers.
Objective: This cross-sectional analysis aimed to identify DP in self-reported disease-free adults using weighed diet diaries and explore relationships with a broad range of CMD risk factors and diet quality.
Methods: Data were collated from five studies conducted in adults living in the UK (2009-2019) and DPs were a posteriori extracted from habitual dietary intake data using principal component analysis. Associations between quartiles (Q) of adherence to the DPs with CMD risk markers, nutrient intakes and the Alternative Healthy Eating Index (AHEI-2010) were evaluated using ANCOVA.
Results: In our cohort [n=646, 58.4% female, mean (SD) age 44 (14) years, and body mass index (BMI) 25.2 (4.0) kg/m²] two DPs explained 12% of the variance in habitual food intake. Highest adherence to DP1 (Q4), characterised by diets rich in fermented dairy, fruits, vegetables, wholegrains, nuts/seeds, unsaturated fats/oils and milk and lower in red meat dishes and processed meat, was associated with a lower BMI, waist circumference, diastolic blood pressure, fasting triacylglycerol, non-high-density lipoprotein-cholesterol, remnant-like particle-cholesterol, and total cholesterol:HDL-C ratio and a higher HDL-C and AHEI-2010 score versus Q1 (all P≤0.006). In contrast, Q4 vs Q1 of DP2, high in refined carbohydrates, milk and unsaturated fats/oils and low in cruciferous vegetables/spinach, and nuts/seeds, was only associated with a lower HDL-C (P=0.006) and AHEI-2010 score (P<0.001).
Conclusions: In disease-free adults, greater adherence to DP1, which broadly aligned with UK food-based dietary guidelines, was favourably associated with diet quality and CMD risk markers. Our findings could contribute to the evidence base for future food-based dietary recommendations, particularly highlighting the importance of fermented dairy foods