816 research outputs found
From traditional resource to global commodities: a comparison of Rhodiola species using NMR spectroscopy - metabolomics and HPTLC
The fast developing international trade of products based on traditional knowledge and their value chains has become an important aspect of the ethnopharmacological debate. The structure and diversity of value chains and their impact on the phytochemical composition of herbal medicinal products has been overlooked in the debate about quality problems in transnational trade. Different government policies and regulations governing trade in herbal medicinal products impact on such value chains. Medicinal Rhodiola species, including Rhodiola rosea L. and Rhodiola crenulata (Hook.f. & Thomson) H.Ohba, have been used widely in Europe and Asia as traditional herbal medicines with numerous claims for their therapeutic effects. Faced with resource depletion and environment destruction, R. rosea and R. crenulata are becoming endangered, making them more economically valuable to collectors and middlemen, and also increasing the risk of adulteration and low quality. We compare the phytochemical differences among Rhodiola raw materials available on the market to provide a practical method for Rhodiola authentication and the detection of potential adulterant compounds. Samples were collected from Europe and Asia and nuclear magnetic resonance spectroscopy coupled with multivariate analysis software and high performance thin layer chromatography techniques were used to analyse the samples. A method was developed to quantify the amount of adulterant species contained within mixtures. We compared the phytochemical composition of collected Rhodiola samples to authenticated samples. Rosavin and rosarin were mainly present in R. rosea whereas crenulatin was only present in R. crenulata. 30% of the Rhodiola samples purchased from the Chinese market were adulterated by other Rhodiola spp. Moreover, 7 % of the raw-material samples were not labelled satifactorily. The utilisation of both 1H-NMR and HPTLC methods provided an integrated analysis of the phytochemical differences and novel identification method for R. rosea and R. crenulata. Using 1H-NMR spectroscopy it was possible to quantify the presence of R. crenulata in admixtures with R. rosea. This quantitative technique could be used in the future to assess a variety of herbal drugs and products. This project also highlights the need to further study the links between producers and consumers in national and trans-national trade
Rhodiola rosea L.:from golden root to green cell factories
Rhodiola rosea L. is a worldwide popular plant with adaptogenic activities that have been and currently are exploited in the traditional medicine of many countries, as well as, examined in a number of clinical trials. More than 140 chemical structures have been identified which belong to several natural product classes, including phenylpropanoid glycosides, phenylethanoids, flavonoids and essential oils, and are mainly stored in the rhizomes and the roots of the plant. A number of mechanisms contribute to the adaptogenic activities of R. rosea preparations and its phytochemical constituents. Among them, the intrinsic inducible mammalian stress responses and their effector proteins, such as heat shock protein 70 (Hsp70), are the most prominent. Due to its popular medicinal use, which has led to depletion of its natural habitats, R. rosea is now considered as endangered in most parts of the world. Conservation, cultivation and micropropagation are all implemented as potential preservation strategies. A number of in vitro systems of R. rosea are being developed as sources of pharmaceutically valuable secondary metabolites. These are greatly facilitated by advances in elucidation of the biosynthetic pathways and the enzymes, which catalyse the production of these secondary metabolites in the plant. In addition, biotechnological approaches show promise towards achieving sustainable production of R. rosea secondary metabolites.</p
A comprehensive survey of the analytical, numerical and experimental methodologies for dynamics of multibody mechanical systems with clearance or imperfect joints
"Available online 19 December 2017"A comprehensive survey of the literature of the most relevant analytical, numerical, and experimental approaches for the kinematic and dynamic analyses of multibody mechanical systems with clearance joints is presented in this review. Both dry and lubricated clearance joints are addressed here, and an effort is made to include a large number of research works in this particular field, which have been published since the 1960′s. First, the most frequently utilized methods for modeling planar and spatial multibody mechanical systems with clearance joints are analyzed, and compared. Other important phenomena commonly associated with clearance joint models, such as wear, non-smooth behavior, optimization and control, chaos, and uncertainty and links’ flexibility, are then discussed. The main assumptions procedures and conclusions for the different methodologies are also examined and compared. Finally, future developments and new applications of clearance joint modeling and analysis are highlighted.This research was supported in part by the China 111 Project (B16003) and the National Natural Science
Foundation of China under Grants 11290151, 11472042 and 11221202. The work was also supported by the
Portuguese Foundation for Science and Technology with the reference project UID/EEA/04436/2013, by
FEDER funds through the COMPETE 2020 – Programa Operacional Competitividade e Internacionalização
(POCI) with the reference project POCI-01-0145-FEDER-006941.info:eu-repo/semantics/publishedVersio
Globally convergent evolution strategies for constrained optimization
International audienceIn this paper we propose, analyze, and test algorithms for constrained optimization when no use of derivatives of the objective function is made. The proposed methodology is built upon the globally convergent evolution strategies previously introduced by the authors for unconstrained optimization. Two approaches are encompassed to handle the constraints. In a first approach, feasibility is first enforced by a barrier function and the objective function is then evaluated directly at the feasible generated points. A second approach projects first all the generated points onto the feasible domain before evaluating the objective function.The resulting algorithms enjoy favorable global convergence properties (convergence to stationarity from arbitrary starting points), regardless of the linearity of the constraints.The algorithmic implementation (i) includes a step where previously evaluated points are used to accelerate the search (by minimizing quadratic models) and (ii) addresses the particular cases of bounds on the variables and linear constraints. Our solver is compared to others, and the numerical results confirm its competitiveness in terms of efficiency and robustness
Strengthening open disclosure in maternity services in the English NHS: the DISCERN realist evaluation study.
BACKGROUND: There is a policy drive in NHS maternity services to improve open disclosure with harmed families and limited information on how better practice can be achieved. OBJECTIVES: To identify critical factors for improving open disclosure from the perspectives of families, doctors, midwives and services and to produce actionable evidence for service improvement. DESIGN: A three-phased, qualitative study using realist methodology. Phase 1: two literature reviews: scoping review of post-2013 NHS policy and realist synthesis of initial programme theories for improvement; an interview study with national stakeholders in NHS maternity safety and families. Phase 2: in-depth ethnographic case studies within three NHS maternity services in England. Phase 3: interpretive forums with study participants. A patient and public involvement strategy underpinned all study phases. SETTING: National recruitment (study phases 1 and 3); three English maternity services (study phase 2). PARTICIPANTS: We completed n = 142 interviews, including 27 with families; 93 hours of ethnographic observations, including 52 service and family meetings over 9 months; and interpretive forums with approximately 69 people, including 11 families. RESULTS: The policy review identified a shift from viewing injured families as passive recipients to active contributors of post-incident learning, but a lack of actionable guidance for improving family involvement. The realist synthesis found weak evidence of the effectiveness of open disclosure interventions in the international maternity literature, but some improvements with organisation-wide interventions. Recent evidence was predominantly from the United Kingdom. The research identified and explored five key mechanisms for open disclosure: meaningful acknowledgement of harm; involvement of those affected in reviews/investigations; support for families' own sense-making; psychological safely of skilled clinicians (doctors and midwives); and knowing that improvements to care have happened. The need for each family to make sense of the incident in their own terms is noted. The selective initiatives of some clinicians to be more open with some families is identified. The challenges of an adversarial medicolegal landscape and limited support for meeting incentivised targets is evidenced. LIMITATIONS: Research was conducted after the pandemic, with exceptional pressure on services. Case-study ethnography was of three higher performing services: generalisation from case-study findings is limited. No observations of Health Safety Investigation Branch investigations were possible without researcher access. Family recruitment did not reflect population diversity with limited representation of non-white families, families with disabilities and other socially marginalised groups and disadvantaged groups. CONCLUSIONS: We identify the need for service-wide systems to ensure that injured families are positioned at the centre of post-incident events, ensure appropriate training and post-incident care of clinicians, and foster ongoing engagement with families beyond the individual efforts made by some clinicians for some families. The need for legislative revisions to promote openness with families across NHS organisations, and wider changes in organisational family engagement practices, is indicated. Examination of how far the study's findings apply to different English maternity services, and a wider rethinking of how family diversity can be encouraged in maternity services research. STUDY REGISTRATION: This study is registered as PROSPERO CRD42020164061. The study has been assessed following RAMESES realist guidelines. FUNDING: This award was funded by the National Institute for Health and Care Research (NIHR) Health and Social Care Delivery Research Programme (NIHR award ref: 17/99/85) and is published in full in Health and Social Care Delivery Research; Vol. 12, No. 22. See the NIHR Funding and Awards website for further award information
Guiding principles for the development and application of solid-phase phosphorus adsorbents for freshwater ecosystems
While a diverse array of phosphorus (P)-adsorbent materials is currently available for application to freshwater aquatic systems, selection of the most appropriate P-adsorbents remains problematic. In particular, there has to be a close correspondence between attributes of the P-adsorbent, its field performance, and the management goals for treatment. These management goals may vary from a rapid reduction in dissolved P to address seasonal enrichments from internal loading, targeting external fluxes due to anthropogenic sources, or long term inactivation of internal P inventories contained within bottom sediments. It also remains a challenge to develop new methods and materials that are ecologically benign and cost-effective. We draw on evidence in the literature and the authors’ personal experiences in the field, to summarise the attributes of a range of P-adsorbent materials. We offer 'guiding principles' to support practical use of existing materials and outline key development needs for new materials
FlyRNAi.org—the database of the Drosophila RNAi screening center: 2012 update
FlyRNAi (http://www.flyrnai.org), the database and website of the Drosophila RNAi Screening Center (DRSC) at Harvard Medical School, serves a dual role, tracking both production of reagents for RNA interference (RNAi) screening in Drosophila cells and RNAi screen results. The database and website is used as a platform for community availability of protocols, tools, and other resources useful to researchers planning, conducting, analyzing or interpreting the results of Drosophila RNAi screens. Based on our own experience and user feedback, we have made several changes. Specifically, we have restructured the database to accommodate new types of reagents; added information about new RNAi libraries and other reagents; updated the user interface and website; and added new tools of use to the Drosophila community and others. Overall, the result is a more useful, flexible and comprehensive website and database
First measurement of the Hubble Constant from a Dark Standard Siren using the Dark Energy Survey Galaxies and the LIGO/Virgo Binary–Black-hole Merger GW170814
International audienceWe present a multi-messenger measurement of the Hubble constant H 0 using the binary–black-hole merger GW170814 as a standard siren, combined with a photometric redshift catalog from the Dark Energy Survey (DES). The luminosity distance is obtained from the gravitational wave signal detected by the Laser Interferometer Gravitational-Wave Observatory (LIGO)/Virgo Collaboration (LVC) on 2017 August 14, and the redshift information is provided by the DES Year 3 data. Black hole mergers such as GW170814 are expected to lack bright electromagnetic emission to uniquely identify their host galaxies and build an object-by-object Hubble diagram. However, they are suitable for a statistical measurement, provided that a galaxy catalog of adequate depth and redshift completion is available. Here we present the first Hubble parameter measurement using a black hole merger. Our analysis results in , which is consistent with both SN Ia and cosmic microwave background measurements of the Hubble constant. The quoted 68% credible region comprises 60% of the uniform prior range [20, 140] km s−1 Mpc−1, and it depends on the assumed prior range. If we take a broader prior of [10, 220] km s−1 Mpc−1, we find (57% of the prior range). Although a weak constraint on the Hubble constant from a single event is expected using the dark siren method, a multifold increase in the LVC event rate is anticipated in the coming years and combinations of many sirens will lead to improved constraints on H 0
The Effects of a Single Bolus of Remifentanil on Corrected QT Interval Change during Sevoflurane Induction
Phylogenetic divergence of GABAB receptor signalling in neocortical networks over adult life.
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