51 research outputs found

    Robust Rolling Horizon Optimisation Model for Offshore Wind Farm Installation Logistics

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    Our approach can be considered as both proactive and reactive, since uncertainty is considered both in creating the initial schedule and the schedule can be updated in real-time

    Cornea engineering on polyester carriers

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    In this study, biodegradable polyester based carriers were designed for tissue engineering of the epithelial and the stromal layers of the cornea, and the final construct was tested in vitro. In the construction of the epithelial layer, micropatterned films were prepared from blends of biodegradable and biocompatible polyesters of natural (PHBV) and synthetic (P(L/DL)LA) origin, and these films were seeded with D407 (retinal pigment epithelial) cells. To improve cell adhesion and growth, the films were coated with fibronectin. To serve as the stromal layer of the cornea, highly porous foams of P(L/DL)LA-PHBV blends were seeded with 3T3 fibroblasts. Cell numbers on the polyester carriers were significantly higher than those on the tissue culture polystyrene control. The cells and the carriers were characterized scanning electron micrographs showed that the foam was highly porous and the pores were interconnected. 3T3 Fibroblasts were distributed quite homogeneously at the seeding site, but probably because of the high thickness of the carrier (∼6 mm); they could not sufficiently populate the core (central parts of the foam) during the test duration. The D407 cells formed multilayers on the micropatterned polyester film. Immunohistochemical studies showed that the cells retained their phenotype during culturing; D407 cells formed tight junctions characteristic of epithelial cells, and 3T3 cells deposited collagen type I into the foams. On the basis of these results, we concluded that the micropatterned films and the foams made of P(L/DL)LA-PHBV blends have a serious potential as tissue engineering carriers for the reconstruction of the epithelial and stromal layers of the cornea. © 2006 Wiley Periodicals, Inc

    Synthesis and characterization of nanosized calcium phosphates by flame spray pyrolysis, and their effect on osteogenic differentiation of stem cells

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    The present study evaluates the synthesis of biocompatible osteoconductive and osteoinductive nano calcium phosphate (CaP) particles by industrially applied, aerosol-derived flame spray pyrolysis method for biomedical field. Calcium phosphate nanoparticles were produced in a range of calcium-to-phosphorus ratio, (1.20–2.19) in order to analyze the morphology and crystallinity changes, and to test the bioactivity of particles. The characterization results confirmed that nanometer-sized, spherical calcium phosphate particles were produced. The average primary particle size was determined as 23 nm by counting more than 500 particles in TEM pictures. XRD patterns, HRTEM, SAED, and SEM analyses revealed the amorphous nature of the as-prepared nano calcium phosphate particles at low Ca/P ratios. Increases in the specific surface area and crystallinity were observed with the increasing Ca/P ratio. TGA–DTA analysis showed that the thermally stable crystal phases formed after 700 °C. Cell culture studies were conducted with urine-derived stem cells that possess the characteristics of mesenchymal stem cells. Synthesized amorphous nanoparticles did not have cytotoxic effect at 5–50 μg/ml concentration range. Cells treated with the as-prepared nanoparticles had higher alkaline phosphatase (ALP) enzyme activity than control cells, indicating osteogenic differentiation of cells. A slight decrease in ALP activity of cells treated with two highest Ca:P ratios at 50 μg/ml concentration was observed at day 7. The findings suggest that calcium phosphate nanoparticles produced in this work have a potential to be used as biomaterials in biomedical applications. © 2015, Springer Science+Business Media Dordrecht

    Polyelectrolyte multilayer films as substrates for photoreceptor cells.

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    Reconstruction of extracellular matrix substrates for delivery of functional photoreceptors is crucial in pathologies such as retinal degeneration and age-related macular degeneration. In this study, we assembled polyelectrolyte films using the layer-by-layer deposition method. The buildup of three different films composed of poly(L-lysine)/chondroitin sulfate (PLL/CSA), poly(L-lysine)/poly(styrenesulfonate) (PLL/PSS), or poly(L-lysine)/hyaluronic acid (PLL/HA) was followed by means of quartz crystal microbalance measurements, optical waveguide light mode spectroscopy, confocal microscopy, and atomic force microscopy. The exponential growth regime and the diffusion of PLL chains from the bulk through the PLL/CSA, PLL/PSS, and PLL/HA films was examined. Evaluation of photoreceptor cell viability was optimal on one layer of PLL (PLL(1)), followed by 10 bilayers of PLL/HA [(PLL/HA)(10)] and 10 bilayers of PLL/CSA [(PLL/CSA)(10)]. The number of bilayers and the type of terminating layer also had a significant influence on the number of photoreceptor cells attached. Functionalized polyelectrolyte multilayer films were obtained by adsorbing basic fibroblastic factor (bFGF) or the insoluble fraction of interphotoreceptor matrix (IPM) on or within polyelectrolyte multilayers. bFGF and IPM adsorption on top of the (PLL/CSA)(10)/PLL polyelectrolyte films increased the number of photoreceptor cells attached and maintained the differentiation of rod and cone cells.journal articleresearch support, non-u.s. gov't2006 Janimporte

    Patients with an Open Abdomen in Asian, American and European Continents: A Comparative Analysis from the International Register of Open Abdomen (IROA)

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    Background: International register of open abdomen (IROA) enrolls patients from several centers in American, European, and Asiatic continent. The aim of our study is to compare the characteristics, management and clinical outcome of adult patients treated with OA in the three continents. Material and methods: A prospective analysis of adult patients enrolled in the international register of open abdomen (IROA). Trial registration: NCT02382770. Results: 1183 patients were enrolled from American, European and Asiatic Continent. Median age was 63 years (IQR 49–74) and was higher in the European continent (65 years, p < 0.001); 57% were male. The main indication for OA was peritonitis (50.6%) followed by trauma (15.4%) and vascular emergency (13.5%) with differences among the continents (p < 0.001). Commercial NPWT was preferred in America and Europe (77.4% and 52.3% of cases) while Barker vacuum pack (48.2%) was the preferred temporary abdominal closure technique in Asia (p < 0.001). Definitive abdominal closure was achieved in 82.3% of cases in America (fascial closure in 90.2% of cases) and in 56.4% of cases in Asia (p < 0.001). Prosthesis were mostly used in Europe (17.3%, p < 0.001). The overall entero-atmospheric fistula rate 2.5%. Median open abdomen duration was 4 days (IQR 2–7). The overall intensive care unit and hospital length-of-stay were, respectively, 8 and 11 days (no differences between continents). The overall morbidity and mortality rates for America, Europe, and Asia were, respectively, 75.8%, 75.3%, 91.8% (p = 0.001) and 31.9%, 51.6%, 56.9% (p < 0.001). Conclusion: There is no uniformity in OA management in the different continents. Heterogeneous adherence to international guidelines application is evident. Different temporary abdominal closure techniques in relation to indications led to different outcomes across the continents. Adherence to guidelines, combined with more consistent data, will ultimately allow to improving knowledge and outcome

    Global validation of the WSES Sepsis Severity Score for patients with complicated intra-abdominal infections : a prospective multicentre study (WISS Study)

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    Background: To validate a new practical Sepsis Severity Score for patients with complicated intra-abdominal infections (cIAIs) including the clinical conditions at the admission (severe sepsis/septic shock), the origin of the cIAIs, the delay in source control, the setting of acquisition and any risk factors such as age and immunosuppression. Methods: The WISS study (WSES cIAIs Score Study) is a multicenter observational study underwent in 132 medical institutions worldwide during a four-month study period (October 2014-February 2015). Four thousand five hundred thirty-three patients with a mean age of 51.2 years (range 18-99) were enrolled in the WISS study. Results: Univariate analysis has shown that all factors that were previously included in the WSES Sepsis Severity Score were highly statistically significant between those who died and those who survived (p <0.0001). The multivariate logistic regression model was highly significant (p <0.0001, R-2 = 0.54) and showed that all these factors were independent in predicting mortality of sepsis. Receiver Operator Curve has shown that the WSES Severity Sepsis Score had an excellent prediction for mortality. A score above 5.5 was the best predictor of mortality having a sensitivity of 89.2 %, a specificity of 83.5 % and a positive likelihood ratio of 5.4. Conclusions: WSES Sepsis Severity Score for patients with complicated Intra-abdominal infections can be used on global level. It has shown high sensitivity, specificity, and likelihood ratio that may help us in making clinical decisions.Peer reviewe

    Posterior tibial nerve stimulation for faecal incontinence after partial spinal injury: Preliminary report

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    PubMed: 17510745Background: This study evaluated the possible effects of posterior tibial nerve stimulation in two patients with faecal incontinence due to partial spinal cord injury. Methods: Posterior tibial nerve stimulation was performed for 30 min, every other day for 4 weeks, and was then repeated every 2 months for three months. Clinical examination, anorectal physiological work-up, faecal incontinence severity index, and quality of life assessments were performed before and after the treatment. Results: After posterior tibial nerve stimulation, patients showed improvement in rectal sensory threshold, pudendal nerve terminal motor latency, Wexner faecal incontinence score, faecal incontinence severity index, faecal incontinence quality of life scales, resting pressure, and maximum squeeze pressure measurements. Conclusions: Posterior tibial nerve stimulation can be an effective method for the treatment of faecal incontinence caused by partial spinal cord injury. © 2007 Springer-Verlag

    Cornea engineering on polyester carriers

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    In this study, biodegradable polyester based carriers were designed for tissue engineering of the epithelial and the stromal layers of the cornea, and the final construct was tested in vitro. In the construction of the epithelial layer, micropatterned films were prepared from blends of biodegradable and biocompatible polyesters of natural (PHBV) and synthetic (P(L/DL)LA) origin, and these films were seeded with D407 (retinal pigment epithelial) cells. To improve cell adhesion and growth, the films were coated with fibronectin. To serve as the stromal layer of the cornea, highly porous foams of P(L/DL)LA-PHBV blends were seeded with 3T3 fibroblasts. Cell numbers on the polyester carriers were significantly higher than those on the tissue culture polystyrene control. The cells and the carriers were characterized scanning electron micrographs showed that the foam was highly porous and the pores were interconnected. 3T3 Fibroblasts were distributed quite homogeneously at the seeding site, but probably because of the high thickness of the carrier (similar to 6 mm); they could not sufficiently populate the core (central parts of the foam) during the test duration. The D407 cells formed multilayers on the micropatterned polyester film. Immunohistochemical studies showed that the cells retained their phenotype during culturing; D407 cells formed tight junctions characteristic of epithelial cells, and 3T3 cells deposited collagen type I into the foams. On the basis of these results, we concluded that the micropatterned films and the foams made of P(L/DL)LA-PHBV blends have a serious potential as tissue engineering carriers for the reconstruction of the epithelial and stromal layers of the cornea. (c) 2006 Wiley Periodicals, Inc
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