5,876 research outputs found

    Step by step optimization of a sperm cryopreservation protocol for spotted wolffish (Anarhichas minor Olafsen, 1772)

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    Spotted wolffish Anarhichas minor reproduction in captivity is dependent on in vitro fertilization. However, low sperm volume with relatively low cell concentration and the lack of gametes synchronization (simultaneous availability of mature eggs and sperm) represent a challenge for the industry. Thus, the development of protocols for sperm storage are crucial. Four sequential experiments were conducted to optimize a sperm cryopreservation protocol for this species. First, three different cryoprotectants (DMSO; 1, 2-propanediol; and methanol) at different concentrations (5, 10, and 20%) were tested for their toxicity. No significant differences (p > 0.05) were detected between the control samples and cryoprotectants at concentration up to 10% DMSO, 10% propanediol, and 20% methanol in terms of motility parameters. Second, using the highest non-toxic concentrations of cryoprotectants, sperm was cryopreserved in 0.5 mL straws, at different distances from the liquid nitrogen (1.5, 2.5, 4.5, and 7.5 cm) that correspond to different freezing rates. Motility parameters after freezing/thawing decreased for all the cryoprotectants (p  0.05) between the two thawing rates. The best results were obtained using 10% DMSO. Finally, the fertilization capacity of cryopreserved sperm (10% DMSO and thawed at 5 °C for 1 min) was tested against fresh sperm using two spermatozoa:egg ratios and 4 h gametes contact time. The ratio of eggs with normal cell cleavage, abnormal cleavage or undeveloped were counted at the 2-4 cell stage. Cryopreserved sperm showed lower fertilization capacity at a concentration of 5 × 104 spermatozoa:egg compared with fresh sperm (p  0.05). To cryopreserve spotted wolffish sperm it is recommended to use 10% DMSO, loaded in 0.5 mL straws, freeze at a height between 4.5 (-14.05 °C/min) and 7.5 cm (-5.9 °C/min) from liquid nitrogen for 10 min and thaw for 1 min at 5 °C (177.9 °C/min). In vitro fertilization with cryopreserved sperm should be performed with a concentration of at least 5 × 105 spermatozoa per egg.WOLFSTORE project (AF0078) supported by the MABIT program from Norway. JS was supported by a Cost action FA1205 AQUAGAMETE and an ERASMUS grant.info:eu-repo/semantics/publishedVersio

    Informed citizen and empowered citizen in health: results from an European survey

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    Background: The knowledge about the relationship between health-related activities on the Internet (i.e. informed citizens) and individuals? control over their own experiences of health or illness (i.e. empowered citizens) is valuable but scarce. In this paper, we investigate the correlation between four ways of using the Internet for information on health or illness and citizens attitudes and behaviours toward health professionals and health systems and establish the profile of empowered eHealth citizens in Europe. Methods: Data was collected during April and May 2007 (N = 7022), through computer-assisted telephone interviews (CATI). Respondents from Denmark, Germany, Greece, Latvia, Norway, Poland and Portugal participated in the survey. The profiles were generated using logistic regressions and are based on: a) socio-demographic and health information, b) the level of use of health-related online services, c) the level of use of the Internet to get health information to decide whether to consult a health professional, prepare for a medical appointment and assess its outcome, and d) the impact of online health information on citizens? attitudes and behavior towards health professionals and health systems. Results: Citizens using the Internet to decide whether to consult a health professional or to get a second opinion are likely to be frequent visitors of health sites, active participants of online health forums and recurrent buyers of medicines and other health related products online, while only infrequent epatients, visiting doctors they have never met face-to-face. Participation in online health communities seems to be related with more inquisitive and autonomous patients. Conclusions: The profiles of empowered eHealth citizens in Europe are situational and country dependent. The number of Europeans using the Internet to get health information to help them deal with a consultation is raising and having access to online health information seems to be associated with growing number of inquisitive and self-reliant patients. Doctors are increasingly likely to experience consultations with knowledgeable and empowered patients, who will challenge them in various ways

    Gas-solid conversion in fluidised bed reactors

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    Asimplified model for gas–solid reactions in fluidised bed (FB) is proposed. Such models already exist for catalytic gas–solid reactions (CGSRs), providing general description of the system in terms of main governing parameters. Expansion of this approach to non-catalytic gas–solid reactions (NCGSRs) is difficult, because the solid reactant takes part in the reaction. Therefore, FB reactor models for NCGSR are usually devised only for specific cases, and a general analysis has not been presented up to date. The present model allows analysis of different types of NCGSR in a generalised way, handling catalytic reactions as a particular, simpler, case. It is shown that the reactor behaviour can be described by three governing dimensionless parameters. Two additional parameters, quantifying the importance of diffusion effects in single particles are also identified, and their impact on reactor behaviour is analysed. Possible simplifications are explored. Model limitations, that is, assumption of isothermal bed and particle and the occurrence of only one reaction, are discussed. Examples are outlined to show the applicability of the methodPublicad

    Game-like 3D visualisation of air quality data

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    The data produced by sensor networks for urban air quality monitoring is becoming a valuable asset for informed health-aware human activity planning. However, in order to properly explore and exploit these data, citizens need intuitive and effective ways of interacting with it. This paper presents CityOnStats, a visualisation tool developed to provide users, mainly adults and young adults, with a game-like 3D environment populated with air quality sensing data, as an alternative to the traditionally passive visualisation techniques. CityOnStats provides several visual cues of pollution presence with the purpose of meeting each user’s preferences. Usability tests with a sample of 30 participants have shown the value of air quality 3D game-based visualisation and have provided empirical support for which visual cues are most adequate for the task at hand.info:eu-repo/semantics/publishedVersio

    Perfect category-graded algebras

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    In a perfect category every object has a minimal projective resolution. We give a criterion for the category of modules over a categorygraded algebra to be perfect.Comment: A sufficient condition is replaced by a criterion. Several references added. 17 page

    Automatic grid refinement criterion for lattice Boltzmann method

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    In all kinds of engineering problems, and in particular in methods for computational fluid dynamics based on regular grids, local grid refinement is of crucial importance. To save on computational expense, many applications require to resolve a wide range of scales present in a numerical simulation by locally adding more mesh points. In general, the need for a higher (or a lower) resolution is not known a priori, and it is therefore difficult to locate areas for which local grid refinement is required. In this paper, we propose a novel algorithm for the lattice Boltzmann method, based on physical concepts, to automatically construct a pattern of local refinement. We apply the idea to the two-dimensional lid-driven cavity and show that the automatically refined grid can lead to results of equal quality with less grid points, thus sparing computational resources and time. The proposed automatic grid refinement strategy has been implemented in the parallel open-source library Palabos

    Effect of Dopants on the Properties of Zirconia‐Supported Iron Catalysts for Ethylbenzene Dehydrogenation with Carbon Dioxide

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    Due to the harmful effects of carbon dioxide to the environment, a lot of work has been carried out aiming to find new applications, which can decrease the emissions or to capture and use it. An attractive application for carbon dioxide is the synthesis of chemicals, especially for producing styrene by ethylbenzene dehydrogenation, in which it increases the catalyst activity and selectivity. In order to find efficient catalysts for the reaction, the effect of cerium, chromium, aluminum, and lanthanum on the properties of zirconia‐supported iron oxides was studied in this work. The modified supports were prepared by precipitation and impregnated with iron nitrate. The obtained catalysts were characterized by thermogravimetry, Fourier transform infrared spectroscopy, X‐ray diffraction, specific surface area measurement, and temperature‐programmed reduction. The catalysts showed different textural and catalytic properties, which were associated to the different phases in the solids, such as monoclinic or tetragonal zirconia, hematite, maghemite, cubic ceria, monoclinic or hexagonal lantana, and rhombohedral chromia, the active phases in ethylbenzene dehydrogenation. The most promising dopant was cerium, which produces the most active catalyst at the lowest temperature, probably due to its ability of providing lattice oxygen, which activates carbon dioxide and increases the reaction rate

    Rates of Ondansetron Administration Prior to Spinal Anesthesia: Evaluating the Practice of Prophylactic Attenuation of Spinal-Induced Hypotension and Bradycardia

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    Background Hypotension and bradycardia are common complications of spinal anesthesia. Intraoperative hypotension and bradycardia may lead to complications that require additional treatment and increase cost. The literature identifies intervention strategies to attenuate spinalinduced hypotension (SIH) and bradycardia.1 Prophylactic administration of ondansetron, a serotonin 5-hydroxytryptamine receptor antagonist, prior to spinal anesthesia is associated with reduced SIH and bradycardia.1,2,3,4,6 The objective of this scholarly project was to report the practice of ondansetron prophylaxis for SIH and bradycardia and the rate of rescue interventions in patients who received ondansetron prior to spinal anesthesia. Methods Retrospective, multi-center observational evidence-based practice project conducted at Providence Sacred Heart Medical Center (PSHMC) and Providence Holy Family Hospital (PHFH) ‱ Approved by the PSHMC Clinical Innovation and Research Council, and deemed exempt by Providence Health Care Institutional Review Board ‱ Data was retrospectively extracted, de-identified, encrypted, and stored in a HIPAA-compliant REDCap database ‱ Eligibility inclusion criteria: obstetric and orthopedic surgery undergoing spinal anesthesia from January 2018 to December 2019, age 18-90 years old, ondansetron administered prior to spinal anesthesia, spinal anesthesia with bupivacaine 0.5% and bupivacaine 0.75% ‱ Exclusion criteria: general anesthesia with ETT/LMA, spinal anesthesia medications other than bupivacaine, other surgical services ‱ Univariate and bivariate analyses to report baseline group comparability and prophylactic ondansetron relationships ‱ Multivariable analysis to report independent risk factors ‱ Multivariate analysis to report descriptive time series Discussion This retrospective EBP project demonstrated a gap in practice with the administration of prophylactic ondansetron to attenuate SIH and bradycardia across service lines and facilities. Rates of prophylactic ondansetron administration prior to spinal anesthesia were 42-73% among obstetric surgery. Rates of prophylactic ondansetron were 2-12% among orthopedic surgery. This project is retrospective and observational in nature, which cannot account for confounding factors that may affect the results. Limitations of this project include the inability to differentiate the use of ondansetron for prophylactic SIH or post-operative nausea and vomiting. Other SIH and bradycardia prevention strategies may have also been performed but not described in this project (such as fluid pre-loading or co-loading, prophylactic low dose phenylephrine infusion, or prophylactic vasopressor prior to spinal anesthesia). This project suggests EBP improvements for the utilization of ondansetron to attenuate SIH and bradycardia.https://digitalcommons.psjhealth.org/other_pubs/1106/thumbnail.jp
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