43,269 research outputs found

    GC–MS study of compounds isolated from Coffea arabica flowers by different extraction techniques

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    Headspace (HS), extractive, and distillative methods were employed to isolate volatile and semivolatile compounds from fresh Coffea arabica flowers. Static HS solid-phase microextraction (HS-SPME), microwave-assisted HS-SPME (MW-HS-SPME) with simultaneous hydrodistillation, and extraction with hexane or supercritical CO2-isolated mixtures in which around 150 different chemical substances were identified or tentatively identified by GC–MS analysis. n-Pentadecane (20–37% relative peak area, RPA) was the most abundant compound in the HS fractions from fresh flowers, followed by 8-heptadecene (8–20% RPA) and geraniol (6–14% RPA). Hydrocarbons (mostly C13–C30 paraffins) were the predominant compound class in all the sorptive extractions (HS-SPME, MW-HS-SPME, distillate), followed by terpenoids or oxygenated compounds (which varied with the isolation technique). Caffeine, a distinctive component of coffee fruits and beans, was also found in relatively high amounts in the supercritical CO2 extract of C. arabica flowers.Departamento Administrativo de Ciencia, Tecnología e Innovación [CO] Colciencias5507-543-31904Programa: Bioprospección y desarrollo de ingredientes naturales para las industrias cosmética, farmacéutica y de productos de aseo con base en la biodiversidad colombianan


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    Even in areas of philosophy of science that don’t involve formal treatments of truth, one’s background view of truth still centrally shapes views on other issues. I offer an informal way to think about truth as trueing, like trueing a bicycle wheel. This holist approach to truth provides a way to discuss knowledge products like models in terms of how well-trued they are to their target. Trueing emphasizes: the process by which models are brought into true; how the idealizations in models are not false but rather like spokes in appropriate tension to achieve a better-trued fit to target; and that this process is not accomplished once and done forever, but instead requires upkeep and ongoing fine-tuning. I conclude by emphasizing the social importance of being a pragmatist about truth in order to accurately answer questions about science such as, “but do we really know that…

    Atypical developmental trajectories of white matter microstructure in prenatal alcohol exposure: Preliminary evidence from neurite orientation dispersion and density imaging

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    IntroductionFetal alcohol spectrum disorder (FASD), a life-long condition resulting from prenatal alcohol exposure (PAE), is associated with structural brain anomalies and neurobehavioral differences. Evidence from longitudinal neuroimaging suggest trajectories of white matter microstructure maturation are atypical in PAE. We aimed to further characterize longitudinal trajectories of developmental white matter microstructure change in children and adolescents with PAE compared to typically-developing Controls using diffusion-weighted Neurite Orientation Dispersion and Density Imaging (NODDI).Materials and methodsParticipants: Youth with PAE (n = 34) and typically-developing Controls (n = 31) ages 8–17 years at enrollment. Participants underwent formal evaluation of growth and facial dysmorphology. Participants also completed two study visits (17 months apart on average), both of which involved cognitive testing and an MRI scan (data collected on a Siemens Prisma 3 T scanner). Age-related changes in the orientation dispersion index (ODI) and the neurite density index (NDI) were examined across five corpus callosum (CC) regions defined by tractography.ResultsWhile linear trajectories suggested similar overall microstructural integrity in PAE and Controls, analyses of symmetrized percent change (SPC) indicated group differences in the timing and magnitude of age-related increases in ODI (indexing the bending and fanning of axons) in the central region of the CC, with PAE participants demonstrating atypically steep increases in dispersion with age compared to Controls. Participants with PAE also demonstrated greater increases in ODI in the mid posterior CC (trend-level group difference). In addition, SPC in ODI and NDI was differentially correlated with executive function performance for PAE participants and Controls, suggesting an atypical relationship between white matter microstructure maturation and cognitive function in PAE.DiscussionPreliminary findings suggest subtle atypicality in the timing and magnitude of age-related white matter microstructure maturation in PAE compared to typically-developing Controls. These findings add to the existing literature on neurodevelopmental trajectories in PAE and suggest that advanced biophysical diffusion modeling (NODDI) may be sensitive to biologically-meaningful microstructural changes in the CC that are disrupted by PAE. Findings of atypical brain maturation-behavior relationships in PAE highlight the need for further study. Further longitudinal research aimed at characterizing white matter neurodevelopmental trajectories in PAE will be important

    Circadian variations in aortic stiffness, sympathetic vasoconstriction, and post-ischemic vasodilation in adults with and without type 2 diabetes.

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    The current literature reveals a lack of information on the circadian variations of some important cardiovascular risk factors related to the work of the heart or the capacity to provide blood and oxygen to various tissues. These factors include aortic stiffness, peripheral vasoconstrictor responsiveness, and post-ischemic vasodilation capacity. Furthermore, it is not clear whether the impact of an external stressor capable of activating the sympathetic nervous system could have greater repercussions on the cardiovascular system in the morning than in the evening. Given the higher incidence of acute cardiovascular events in the morning than in the evening, the studies undertaken in this thesis aim to investigate the circadian variations of these factors that are linked to cardiovascular risk, both at rest and during acute activation of the sympathetic nervous system. Type 2 diabetes (T2DM) is a condition that induces deleterious changes in cardiovascular function, impacting cardiovascular mortality and morbidity. Thus, the impact of diabetes will be evaluated. As a secondary purpose, considering the sex differences in the incidence and prognosis of cardiovascular disease, the effect of sex will be evaluated. Aortic stiffness proved not to be increased in the morning compared to the evening at specific times when the cardiovascular risk is significantly different, both at rest and during sympathetic activation. However, while healthy older women show similar aortic stiffness values compared to their male counterparts during acute stress, older women with T2DM reported greater aortic stiffness compared to men with T2DM. The post-ischemic forearm vasodilation is blunted in the morning compared to the evening in healthy elderly and such an attenuated vasodilation capacity impairs blood flow supply towards the ischemic area. The presence of T2DM does not affect vasodilation capacity and reactive hyperemia, but induces circadian variations in arterial pressure. The peripheral vasoconstriction triggered by a standardized sympathetic stressor is similar between morning and evening, regardless of the presence of T2DM and reduced baseline vascular conductance values in the morning. However, the peripheral vasoconstriction responsiveness is blunted in individuals with T2DM than in healthy ones as sympathetic activation induces vasodilation on the contralateral forearm in individuals with T2DM and vasoconstriction in healthy age-matched subjects. This finding highlights a neurovascular response to an external stressor altered by T2DM. Taken together, our findings suggest that the baseline state of constriction of the peripheral vascular tissue is greater in the morning than in the evening, but this fact is not due to greater sympathetic vasoconstriction responsiveness in the morning. Higher morning vasoconstriction at baseline however affects the capacity of a vascular tissue to dilate and, in turn, to supply blood to an ischemic tissue. Similar sympathetic vasoconstriction responsiveness between morning and evening is a likely factor explaining similar or lower values of central artery stiffness in the morning than in the evening, not only at rest but also during sympathetic excitation. Paradoxically, adults with T2DM report an increase in sympathetic-mediated dilatation capacity on the vascular tissue, which might be a defense mechanism that allows to reduce the central pressor response during sympathetic excitation

    Effects of combined interventions to optimize recovery during high-intensity exercises in trained individuals

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    Background Team sports such as ice hockey offer the opportunity of recovery breaks between high-intensity work intervals. Strategies aiming to mitigate fatigue during intermittent physical activity are seldom investigated in combination, although several different mechanisms of action exist, which might be cumulative and therefore beneficial for athletes. This study examined the effects of seven combined recovery interventions (enhanced recovery package, ERP) on exercise capacity during intermittent high-intensity cycling. Methods Sixteen trained men (age: 24.8 ± 3.4 y; maximal power output: 5.0 ± 0.5 W・kg-1) completed a repeated sprint exercise (RSE) protocol consisting of six 30-s cycling sprints with 3-min breaks between each sprint. The first sprint was always performed at a similar load, while sprints 2-6 were performed with the ergometer in cadence dependent mode (0.075 kg・kg-1). During the breaks, the ERP, Placebo, or Control protocols were applied, all on different days. The ERP condition combined 1) 3-min ice gel packs to the neck; 2, 3) 5-s mouth rinsing of a 10% carbohydrate and caffeine (6 mg・kg-1), 4) ingestion of 50 ml of a 6% carbohydrate solution, 5, 6) 30 s of all-out hyperventilation while breathing 100% O2 (hyperoxia); and finally, 7) potentiation maneuvers via performance of 3 half-squats at 75% of one maximal repetition. The placebo intervention masked the interventions except for the ice packs and potentiation maneuvers. Participants were told they were performing a simplified version with only the known beneficial interventions. Power output, heart rate, blood lactate concentration, rate of perceived exertion and gas exchange were compared between the ERP and Placebo conditions. Results Mean power output (W) was significantly higher for the ERP condition compared to Placebo (570 ± 74 W vs. 560 ± 71 W, t(15) = 4.603, P < 0.001, 95% CI diff = 5 – 14 W, dz = 1.15). The rate of power decrement over sprints 2-6 was very similar between trials (ERP -14.2 W per sprint, 95% CI = -21.6 – -6.8 W; Placebo -17.4 W per sprint, 95% CI = -24.7 – -10.2 W per sprint, P = 0.407). Mean heart rate was higher (3 ± 4 bpm, P = 0.012) for the ERP compared to the Placebo condition, as was breathing frequency (2.4 ± 4.0 breaths・min-1, P = 0.028) and respiratory exchange ratio (0.12 ± 0.06, P < 0.001). Oxygen uptake was 80 ± 109 ml・min-1 (P = 0.013) lower for ERP. No differences were found with regards to the rate of perceived exertion or blood lactate concentration. Conclusion ERP optimized recovery when applied during the breaks of a high-intensity repeated sprint exercise and shows a small but consistent increase in mean power output. It is possible that the ERP prevented a loss of aerobic efficiency. A top-down approach when tailoring packages for individual athletes might overcome the issue of small improvements that are difficult to detect when strategies are tested in isolation

    Small newborns in post-conflict Northern Uganda: Burden and interventions for improved outcomes

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    Introduction: A small newborn can be the result of either a low birthweight (LBW), or a preterm birth (PB), or both. LBW can be due to either a preterm appropriate-for gestational-age (preterm-AGA), or a term small-for-gestational age (term-SGA) or intrauterine growth restriction (IUGR). An IUGR is a limited in-utero foetal growth rates or foetal weight < 10th percentile. Small newborns have an increased risk of dying, particularly in low-resource settings. We set out to assess the burden, the modifiable risk factors and health outcomes of small newborns in the post-conflict Northern Ugandan district of Lira. In addition, we studied the use of video-debriefing when training health staff in Helping Babies Breathe. Subjects and methods: In 2018-19, we conducted a community-based cohort study on 1556 mother-infant dyads, nested within a cluster randomized trial. In our cohort study, we estimated the incidence and risk factors for LBW and PB and the association of LBW with severe outcomes. We explored the prevalence of and factors associated with neonatal hypoglycaemia, as well as any association between neonatal death and hypoglycaemia. In addition, we conducted a cluster randomized trial to compare Helping Babies Breathe (HBB) training in combination with video debriefing to the traditional HBB training alone on the attainment and retention of health worker neonatal resuscitation competency. Results: The incidence of LBW and PB in our cohort was lower than the global estimates, 7.3% and 5.0%, respectively. Intermittent preventive treatment for malaria was associated with a reduced risk of LBW. HIV infection was associated with an increased risk of both LBW and PB, while maternal formal education (schooling) of ≥7 years was associated with a reduced risk of LBW and PB. The proportions of neonatal deaths were many-folds higher among LBW infants compared to their non-LBW counterparts. The proportion of neonatal deaths among LBW was 103/1000 live births compared to 5/1000 among the non-LBW. The prevalence of neonatal hypoglycaemia in our cohort was 2.5%. LBW and PB each independently were associated with an increased risk of neonatal hypoglycaemia. Neonatal hypoglycaemia was associated with an increased risk of hospitalisation and severe outcomes. We demonstrated that neonatal resuscitation training with video debriefing, improved competence attainment and retention among health workers, compared to traditional HBB training alone. Conclusion: In northern Uganda, small infants still have a many-fold higher risk of dying compared to normal infants. In addition, small infants are also at more risk of neonatal hypoglycaemia compared to normal infants. Efforts are needed to secure essential newborn care, should we reach the target of Sustainable Development Goal number 3.2 of reducing infant mortality to less than 12/1000 live births by 2030


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    Sterculia quadrifida R.Br. Bark decoction is used to treat hepatitis and consumed as a tonic by Timorese in the East Nusa Tenggara Province, Indonesia. Raw herbal materials are susceptible to fungi contamination, have limitations in transportation, and have low economic value. Processing the bark into powder packed in tea bags is expected to overcome these obstacles. Stevia, ginger, and mint leaves are herbs often added to herbal drink formulas. This study aimed to evaluate the antioxidant capacity, total flavonoid content (TFC), total phenol content (TPC), physicochemical properties, and sensory properties of six formulas, namely: (F1) pure S. quadrifida bark; (F2) bark of S. quadrifida and leaves of stevia; (F3) stem bark of S. quadrifida and ginger; (F4) bark of S. quadrifida, stevia, and ginger; (F5) bark of S. quadrifida and mint leaves; (F6) bark of S. quadrifida, stevia, and mint. Total phenolic content was measured using the Folin-Ciocalteu method, and total flavonoids were determined using the AICI3 method. Antioxidant activity was measured using the 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) method. The TPC of S. quadrifida tea ranged from 14.09±0.7 to 68.20±0.95% Gallic Acid Equivalent (GAE), and the TFC ranged from 0.03±0.005 to 0.09±0.004% QE. The Ascorbic acid Equivalent Antioxidant Capacity (AEAC) of F1, F2, F5, and F6 were insignificantly different. The pure S. quadrifida bark formula (F1) contained the highest levels of antioxidants (1,044.3±28.48 ppm Ascorbic Acid Equivalent (AAE)). Formulas with the addition of stevia, mint, and ginger showed weaker antioxidant activity than pure S. quadrifida. The formula of pure S. quadrifida bark (F1) and S. quadrifida with the addition of stevia (F2) have the potential to be developed as commercial herbal tea

    Revealing the Inhibition of Tea Cultivar ‘Ziyan’ Root Growth Caused by High Nitrogen Based on Physiological, Metabolite, and Transcriptome Analyses

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    Nitrogen (N) is a key regulator in the growth of tea plants and the synthesis of amino acids (AAs) and related secondary metabolites, thus affecting the yield and quality of tea leaves. Increased N fertilization significantly improves the yield and quality of tea plants, but applying excess nitrogen wastes resources and causes pollution problems. Herein, we employed morphological, physiological, metabolomic, and RNA-seq methods to study the response of ‘Ziyan’ roots to high N. High N supply induced an increase in arginine (Arg), asparagine (Asn), and glutamine (Gln) in roots and simultaneously decreased sucrose, polyphenols, and caffeine contents. High N reduced the length, volume, number, and activity of the roots by 10.63%, 25.00%, 26.95%, and 14.50%, respectively, which inhibited ‘Ziyan’ root growth, probably by disturbing the regulation of carbon and nitrogen metabolism in the tea plant. According to the Kyoto Encyclopedia of Genes and Genome (KEGG) enrichment analysis, AAs, flavonoids, and flavonol-related pathways were relatively active after supplying high N. In addition, the transcriptome analysis identified NRT1/PTR and GOGAT as key genes, and the transcription factors (e.g., AP2/ERF, MYB, and WRKY) and auxins were actively involved in the high N stress response of ‘Ziyan’ roots. These findings will help us understand the adaptive mechanism of high N supply in tea tree roots and provide a reference for guiding the fertilization of ‘Ziyan’ tea plants

    Platform Economy and Product Liability: Old Rules for New Markets

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    According to statistics, Amazon is one of the most-used online marketplaces worldwide. The COVID-19 pandemic and the ensuing lockdowns to reduce the spread of the virus have shown how critical online marketplaces are to enable e-commerce and keep commercial transactions alive, especially in such times when regular commerce is disrupted. However, when we buy online, we have no chance of examining whether the product works or whether it is defective. If something goes wrong when we buy a product from a third-party seller through Amazon, as consumers, we then face the challenge of trying to file a claim for the damages that might have arisen due to the defectiveness of the product. This article explores Amazon's position in this scenario, with reference to the case law from both US and EU courts and regulations, not solely from the point of view of Product Liability Law, but also according to the E-Commerce Directive liability