2,659 research outputs found

    Palladium Nanoparticles Supported on Ce-Metal–Organic Framework for Efficient CO Oxidation and Low-Temperature CO2 Capture

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    In this article, we report the lowest-temperature CO oxidation catalyst supported on metal–organic frameworks (MOFs). We have developed a facile, general, and effective approach based on microwave irradiation for the incorporation of Pd nanoparticle catalyst within Ce-MOF. The resulting Pd/Ce-MOF material is a unique catalyst that is capable of CO oxidation at modest temperatures and also of efficient uptake of the product CO2 gas at low temperatures. The observed catalytic activity of this material toward CO oxidation is significantly higher than those of other reported metal nanoparticles supported on MOFs. The high activity of the Pd/Ce-MOF catalyst is due to the presence of Ce(III) and Ce(IV) ions within the metal–organic framework support. The Pd nanoparticles supported on the Ce-MOF store oxygen in the form of a thin palladium oxide layer at the particle–support interface, in addition to the oxygen stored on the Ce(III)/Ce(IV) centers. Oxygen from these reservoirs can be released during CO oxidation at 373 K. At lower temperatures (273 K), the Pd/Ce-MOF has a significant CO2 uptake of 3.5 mmol/g

    Diagnosis of Combination Faults in a Planetary Gearbox using a Modulation Signal Bispectrum based Sideband Estimator

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    This paper presents a novel method for diagnosing combination faults in planetary gearboxes. Vibration signals measured on the gearbox housing exhibit complicated characteristics because of multiple modulations of concurrent excitation sources, signal paths and noise. To separate these modulations accurately, a modulation signal bispectrum based sideband estimator (MSB-SE) developed recently is used to achieve a sparse representation for the complicated signal contents, which allows effective enhancement of various sidebands for accurate diagnostic information. Applying the proposed method to diagnose an industrial planetary gearbox which coexists both bearing faults and gear faults shows that the different severities of the faults can be separated reliably under different load conditions, confirming the superior performance of this MSB-SE based diagnosis scheme

    Novel Uses of Video to Accelerate the Surgical Learning Curve

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    Surgeons are under enormous pressure to continually improve and learn new surgical skills. Novel uses of surgical video in the preoperative, intraoperative, and postoperative setting are emerging to accelerate the learning curve of surgical skill and minimize harm to patients. In the preoperative setting, social media outlets provide a valuable platform for surgeons to collaborate and plan for difficult operative cases. Live streaming of video has allowed for intraoperative telementoring. Finally, postoperative use of video has provided structure for peer coaching to evaluate and improve surgical skill. Applying these approaches into practice is becoming easier as most of our surgical platforms (e.g., laparoscopic, and endoscopy) now have video recording technology built in and video editing software has become more user friendly. Future applications of video technology are being developed, including possible integration into accreditation and board certification.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140152/1/lap.2016.0100.pd

    Self-service infrastructure container for data intensive application

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    Cloud based scientific data management - storage, transfer, analysis, and inference extraction - is attracting interest. In this paper, we propose a next generation cloud deployment model suitable for data intensive applications. Our model is a flexible and self-service container-based infrastructure that delivers - network, computing, and storage resources together with the logic to dynamically manage the components in a holistic manner. We demonstrate the strength of our model with a bioinformatics application. Dynamic algorithms for resource provisioning and job allocation suitable for the chosen dataset are packaged and delivered in a privileged virtual machine as part of the container. We tested the model on our private internal experimental cloud that is built on low-cost commodity hardware. We demonstrate the capability of our model to create the required network and computing resources and allocate submitted jobs. The results obtained shows the benefits of increased automation in terms of both a significant improvement in the time to complete a data analysis and a reduction in the cost of analysis. The algorithms proposed reduced the cost of performing analysis by 50% at 15 GB of data analysis. The total time between submitting a job and writing the results after analysis also reduced by more than 1 hr at 15 GB of data analysis

    Neonatal iron distribution and infection susceptibility in full term, preterm and low birthweight babies in urban Gambia: study protocol for an observational study.

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    Background: Neonatal infection is the third largest cause of death in children under five worldwide.  Nutritional immunity is the process by which the host innate immune system limits nutrient availability to invading organisms. Iron is an essential micronutrient for both microbial pathogens and their mammalian hosts. Changes in iron availability and distribution have significant effects on pathogen virulence and on the immune response to infection. Our previously published data shows that, during the first 24 hours of life, full-term neonates have reduced overall serum iron. Transferrin saturation decreases rapidly from 45% in cord blood to ~20% by six hours post-delivery. Methods: To study neonatal nutritional immunity and its role in neonatal susceptibility to infection, we will conduct an observational study on 300 full-term normal birth weight (FTB+NBW), 50 preterm normal birth weight (PTB+NBW), 50 preterm low birth weight (PTB+LBW) and 50 full-term low birth weight (FTB+LBW), vaginally-delivered neonates born at Kanifing General Hospital, The Gambia. We will characterize and quantify iron-related nutritional immunity during the early neonatal period and use ex vivo sentinel bacterial growth assays to assess how differences in serum iron affect bacterial growth. Blood samples will be collected from the umbilical cord (arterial and venous) and at serial time points from the neonates over the first week of life. Discussion: Currently, little is known about nutritional immunity in neonates. In this study, we will increase understanding of how nutritional immunity may protect neonates from infection during the first critical days of life by limiting the pathogenicity and virulence of neonatal sepsis causing organisms by reducing the availability of iron. Additionally, we will investigate the hypothesis that this protective mechanism may not be activated in preterm and low birth weight neonates, potentially putting these babies at an enhanced risk of neonatal infection. Trial registration: clinicaltrials.gov ( NCT03353051) 27/11/2017

    Understanding the psychosocial impact of weight loss following bariatric surgery: a qualitative study

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    Abstract Background Bariatric surgery leads to changes in mental health, quality of life and social functioning, yet these outcomes differ among individuals. In this study, we explore patients’ psychosocial experiences following bariatric surgery and elucidate the individual-level factors that may drive variation in psychosocial outcomes. Methods Eleven semi-structured focus groups with Michigan Bariatric Surgery Collaborative (MBSC) patients (n = 77). Interviews were audio recorded, transcribed verbatim, and analyzed using a grounded theory approach. Data on participant demographic characteristics were abstracted from the MBSC clinical registry. Results Most focus group participants were female (89%), white (64%), and married (65%). We identified three major themes: (1) change in self-perception; (2) change in perception by others; and (3) change in relationships. Each theme includes 3 sub-themes, demonstrating a range of positive and negative psychosocial experiences. For example, weight loss led to increased self-confidence among many participants while others described a loss of self-identity. Some noted improved relationships with family or friends while others experienced worsening or even loss of relationships due to perceived jealousy. Conclusion Weight loss following bariatric surgery leads to complex changes in self-perception and inter-personal relationships, which may be proximal mediators of commonly assessed mental health outcomes such as depression. Individuals considering bariatric surgery may benefit from anticipatory guidance about these diverse experiences, and post-surgical longitudinal monitoring should include evaluation for adverse psychosocial events.https://deepblue.lib.umich.edu/bitstream/2027.42/146725/1/40608_2018_Article_215.pd

    Compositional Evaluation of Pulp and Seed of Blood Plum (Haematostaphis barteri), a Wild Tree Found in Taraba State, Nigeria

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    Traditional leafy vegetables represent inexpensive but high quality nutritional sources for the poor segment of the population especially in developing world like Nigeria, where malnutrition is wide spread. Blood plum (Haematostaphis barteri) is an under–utilized leafy vegetable belonging to the Anacardiacea family. A comparative study was carried out on proximate composition and amino acid profile of pulp and seed of H. barteri. The proximate composition values (%) for pulp and seed samples were found to be as follows: Moisture (3.56 and 2.75), ash (2.97 and 3.92), crude fat (17.76 and 29.68), crude protein (21.81 and 29.38), crude fibre (8.44 and 2.40), and carbohydrate (45.48 and 31.88). The calculated fatty acids and metabolizable energy were 14.21 and 23.74%; 1801.05 and 2139.58 kJ/100g, respectively. The high metabolizable energy values showed that the samples have an energy concentration more favourable than cereals, and which compare favourably well with those of legumes. The amino acid profiles revealed that pulp and seed samples of H. barteri contained nutritionally useful quantities of most of the essential amino acids. The total amino acids (TAA), total essential amino acids (TEAA) (with His), total sulphur amino acids (TSAA), and essential aromatic amino acids (EArAA) for the pulp and seed samples were 53.39 and 67.07; 26.49 and 34.28; 1.21 and 2.59; 2.70 and 3.37, respectively. However, supplementation of essential amino acid is required in a dietary formula based on H. barteri (pulp and seed), when comparing the EAAs in this report with the recommended FAO/WHO provisional pattern. The limiting EAAs in the pulp and seed of H. barteri were Leu and Lys, respectively. Keyword: Proximate, amino acids, pulp, seed, Haematostaphis barter

    Limitations of biosurfactant strength produced by bacteria

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    Biosurfactants which reduce the surface or interfacial tension of liquids and act as emulsifiers, foaming and dispersing agents with low toxicity, are finding increasing applications in biotechnology and driving the search for novel compounds for further exploitation. Potential biosurfactants sourced from bacteria are often selected first by qualitative assessment of surface tension using simple assays such as the drop collapse technique or by quantitative tensiometry measuring air-liquid interfacial tension of cell-free culture supernatants or purified samples, and subsequently tested for appropriate physicalchemical behaviours using a range of application-specific assays. Highly active or strong biosurfactants have been reported to reduce the surface tension of water to approximately 22 – 25 mN.m-1, and show a range of behaviours determined by the choice of conditions (temperature, pH, salt concentration, etc.) used to test particular aqueous-hydrophobic (oil) mixtures. However, recent analyses of biosurfactant strengths using a predictive statistical approach (Individual distribution identification) have shown that it is unlikely that new compounds will be identified able to significantly reduce aqueous surface tensions below 24 mN.m-1. The mechanistic basis of this limit requires an explanation of why stronger compounds are not produced by bacteria, with a limitation of self-harm to producing cells probably the most likely biophysical explanation. However, behavioural analyses using a combination of emulsion, foam stability and oil-dispersion assays indicates high chemical diversity exists amongst biosurfactants exhibiting the strongest levels of activity (24 – 28 mN.m-1), suggesting that bacteria are still likely to provide a rich source of potentially novel compounds for use in biotechnology
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