51 research outputs found

    Similarities and differences between patients included and excluded from a randomized clinical trial of vitamin d supplementation for improving glucose tolerance in prediabetes: interpreting broader applicability

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    BACKGROUND: Randomized Clinical Trial (RCT) designs range from highly selective resulting in lack of external validity to more inclusive, requiring large sample sizes to observe significant results. Few publications, however, have compared excluded to enrolled participants. We aimed to assess our trial’s design based on the effectiveness versus efficacy continuum using the Pragmatic-Explanatory Continuum Indicator Summary (PRECIS) tool and to compare included and excluded patients. METHODS: Fifteen members of endocrinology section completed PRECIS for DIVA (D-Vitamin Intervention in VA) trial; an RCT evaluating vitamin D supplementation in improving dysglycemia in patients with prediabetes. Retrospective chart review compared subjects excluded (OUT) to those included (IN) in RCT. Student’s t and Chi-square tests were used to compare continuous and categorical variables. Additionally, multiple logistic regression was completed. RESULTS: PRECIS scores were nearly universally pragmatic. 178 patients enrolled in DIVA trial were compared with 178 randomly selected patients excluded from study involvement. There was no significant difference between IN and OUT for the majority of the continuous and all of the categorical variables. Multivariate logistic regression identified only the A1c, HDL and Charlson Index as significant predictors of a participant’s inclusion or exclusion. There was higher HDL (51.3(13.9) versus 44.6(10.1), P = 0.001) and Charlson Index (2.85(1.6) versus 2.2(1.17), P = 0.001) for OUT versus IN groups. Subanalysis of excluded patients in A1c range 5.7 to 6.9, had lower BMI (30.7(3.4) versus 32(2.7), P = 0.002) but higher HDL (mg/l: 49.7(11.8) versus 44.6(10.1), P = 0.001) and Charlson index (2.85(1.6) versus 2.2(1.17), P = 0.001) than included participants. Additionally, there was a trend towards higher rates of cancer (22.9 % versus 12.9 %, P = 0.033) but less psychiatric problems (56.2 % versus 72.5 %, P = 0.026) and thiazide diuretic use (18.1 % versus 29.8 %, P = 0.034). CONCLUSION: DIVA trial design appears to favor broad clinical applicability. The majority of objectively compared variables did not different between patients included and excluded from this RCT. Advice based on the evidence from this RCT may be applicable to a larger group of patients than those fitting inclusion/exclusion criteria alone. TRIAL REGISTRATION: ClinicalTrials.gov NCT01375660 (registered 15 June 2011). ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13063-015-0812-0) contains supplementary material, which is available to authorized users

    Wax-wetting sponges for oil droplets recovery from frigid waters

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    Energy-efficient recovery of oil droplets from ice-cold water, such as oil sands tailings, marine, and arctic oil spills, is challenging. In particular, due to paraffin wax crystallization at low temperatures, the crude oil exhibits high viscosity, making it difficult to collect using simple solutions like sponges. Here, we report a wax-wetting sponge designed by conforming to the thermoresponsive microstructure of crude oil droplets. To address paraffin wax crystallization, we designed the sponge by coating a polyester polyurethane substrate with nanosilicon functionalized with paraffin-like octadecyl ligands. The wax-wetting sponge can adsorb oil droplets from wastewater between 5° and 40°C with 90 to 99% removal efficacy for 10 cycles. Also, upon rinsing with heptol, the adsorbed oil is released within seconds. The proposed approach of sponges designed to conform with the temperature-dependent microstructure of the crude oils could enable cold water technologies and improve circular economy metrics in the oil industry

    Cryopreservation Effect on Proliferative and Chondrogenic Potential of Human Chondrocytes Isolated from Superficial and Deep Cartilage

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    [Abstract] Objectives: To compare the proliferative and chondrogenic potential of fresh and frozen chondrocytes isolated from superficial and deep articular cartilage biopsies. Materials and Methodology: The study included 12 samples of fresh and frozen healthy human knee articular cartilage. Cell proliferation was tested at 3, 6 and 9 days. Studies of mRNA quantification, protein expression and immunofluorescence for proliferation and chondrogenic markers were performed. Results: Stimulation of fresh and frozen chondrocytes from both superficial and deep cartilage with fetal bovine serum produced an increase in the proliferative capacity compared to the non-stimulated control group. In the stimulated fresh cells group, the proliferative capacity of cells from the deep biopsy was greater than that from cells from the superficial biopsy (0.046 vs 0.028, respectively, p<0.05). There was also a significant difference between the proliferative capacity of superficial zone fresh (0.028) and frozen (0.051) chondrocytes (p<0.05). CCND1 mRNA and protein expression levels, and immunopositivity for Ki67 revealed a higher proliferative capacity for fresh articular chondrocytes from deep cartilage. Regarding the chondrogenic potential, stimulated fresh cells showed higher SOX9 and Col II expression in chondrocytes from deep than from superficial zone (p<0.05, T student test). Conclusions: The highest rate of cell proliferation and chondrogenic potential of fresh chondrocytes was found in cells obtained from deep cartilage biopsies, whereas there were no statistically significant differences in proliferative and chondrogenic capacity between biopsy origins with frozen chondrocytes. These results indicate that both origin and cryopreservation affect the proliferative and chondrogenic potential of chondrocytes.Servizo Galego de Saúde; PS07/84Instituto de Salud Carlos III; CIBER BBN CB06-01-0040Ministerio Ciencia e Innovacion; PLE2009-0144Ministerio Ciencia e Innovación; PI 08/202

    Surface Engineered Sponges Enable Oily Wastewater Remediation and Residual Oil Recovery

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    In the US, steam-¬based oil extraction processes generate over 15 billion liters of emulsified oil contaminated wastewater annually. For sustainability, these effluents need to be remediated and/or recycled. However, the complex properties (pH, dissolved salts, and high temperature) of effluents pose challenges for removal of oil microdroplets removal using current separation methods. This thesis developed a new process to selectively recover crude oil microdroplets from wastewater using inexpensive sponges. This process synergistically uses sponge surface properties and pre-existing ionic and thermal energies of the wastewater to achieve 95-99% oil removal efficacy from wastewater. First, an acid-base polymeric sponge was applied to remove crude oil microdroplets from water. In acidic or basic environments, acid-base polymers acquire surface charge due to protonation or dissociation of surface functional groups. This property is invoked to adsorb crude oil microdroplets from water using a polyester polyurethane sponge. Using the surface charge of the sponge and oil droplets, the solution pH (5.6) for 99% oil removal efficacy was predicted and verified through adsorption experiments. The droplet adsorption onto the sponge was governed by physisorption, and the driving forces were attributed to electrostatic attraction and Lifshitz-van der Waals forces. The sponge was regenerated and reused multiple times by mechanical compression. Next, to remove oil microdroplets from water at broad pH conditions, an innovative surface engineered sponge (SEnS) was designed by combining surface chemistry, surface charge, roughness, and surface energy. Under all pH conditions, the SEnS rapidly adsorbed oil microdroplets with 95-99% removal efficiency predominantly by electrostatic attraction and Lifshitz-van der Waals forces. Furthermore, at the best pH value, 92% of the oil was adsorbed within 10 min due to synergistic charge attraction. The adsorbed oil was recovered by rinsing with a diluent while the cleaned SEnS was reused multiple times for oil adsorption. Subsequently, crude oil is recovered from the diluent using distillation. Due to the process efficacy, sponge reuse, and oil recovery, this adsorptive-recovery method using sponges demonstrates great potential for the industrial oil recovery from wastewater. Furthermore, this work lays foundation for the development of new SEnS with the potential to revolutionize water treatment technologies.Ph.D.2019-10-11 00:00:0

    Enhancement of Accuracy in Multi-Point Stretch Forming: Cushion Stretching

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    Multi-point stretch forming (MPSF) is one of the flexible manufacturing processes that uses the reconfigurable tools to produce the three-dimensional sheet metal components. An elastic cushion is placed between the tools and sheet surfaces to avoid direct contact and reduce the dimples as well as wrinkles. The cushion is also known to play an important role as it directly affects the component surface characteristics (accuracy and quality) and thickness strain distribution. An attempt made to apply stretching on the cushion resulted in enhancement of accuracy. In the present work, an analytical methodology is proposed to predict the initial thickness of cushion and stretching load necessary to apply on the cushion. FEA of MPSF of the spherical geometry is carried out with and without application of stretching load on the cushion. Results indicate that effective stress and strain distributions are more uniform when the stretching is applied to cushion thickness in certain range. Proposed methodology can be effectively used to determine initial cushion thickness before stretch and stretch load necessary to achieve chosen final cushion thickness to enhance the accuracy of sheet metal components formed using MPSF. © 202

    Importance of machine compliance to quantify electro-plastic effect in electric pulse aided testing: An experimental and numerical study

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    Electric pulse aided deformation (EPAD) of metals reduces the flow stress due to both thermal (expansion as well as softening) and electro-plastic (EP) effects. To quantify the electro-plastic effect during pulse application, close prediction of stress-drop due to thermal effects is very important. Testing machine relaxes due to sudden drop in stress at the instant of pulse application and this aspect must be considered in deformation analysis of the predictive methodology to accurately estimate the stress-drop. Coupled electro-thermo-mechanical finite element analysis by incorporating the testing machine stiffness is carried out during the present work to estimate the stress-drop due to thermal effects and validated. Results indicate that the testing machine stiffness significantly influences the stress-drop. In addition, experimental and numerical studies carried out during the present work explain the role of relative rate of deformation and thermal expansion during pulse application to quantify the EP effect. In the present work, cold-rolled and annealed automotive (C–Mn 440) steel is used and there is a reasonable EP effect. © 2022 The Society of Manufacturing Engineer

    Thermoresponsive hydrogels for atmospheric water vapor harvesting

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    Currently, freshwater scarcity is a global challenge that is threatening four billion people across the world. To satisfy people’s increasing freshwater demand, harvesting atmospheric water from the air could be an alternative way. This work developed copolymer P(NIPAM-co-15%BzDMA) hydrogels to harvest atmospheric water vapor. Two methods were investigated to improve its adsorption performance: decreasing synthesis temperature below the LCST and copolymerizing with the optimum amount of quaternary ammonium salt (QAS). We found these two methods can effectively improve the water vapor uptake. After copolymerizing NIPAM with 15% QAS at 20°C, the water vapor uptake could be increased by almost 20% to 232 mg/g at 20°C and P/P0 of 0.75 compared with pure PNIPAM prepared at 60°C (194 mg/g). The significant increase can be attributed to the more uniform porous structure and the hygroscopicity of QAS. After coating PNIPAM onto the PESPU sponge skeleton, the PESPU-PNIPAM_60 could adsorb 180 mg/g gas water at 20°C and P/P0 of 0.75, and the modified sponges inherit the switchable wettability from PNIPAM. This research provides polymer processing parameters and their character for harvesting water vapor from the air with hydrogels

    Otosclerosis in the 1960s, 1970s, 1980s, and 1990s

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