23 research outputs found

    Clip placement to prevent delayed bleeding after colonic endoscopic mucosal resection (CLIPPER): study protocol for a randomized controlled trial

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    Background: Endoscopic mucosal resection (EMR) for large colorectal polyps is in most cases the preferred treatment to prevent progression to colorectal carcinoma. The most common complication after EMR is delayed bleeding, occurring in 7% overall and in approximately 10% of polyps ≥ 2 cm in the proximal colon. Previous research has suggested that prophylactic clipping of the mucosal defect after EMR may reduce the incidence of delayed bleeding in polyps with a high bleeding risk. Methods: The CLIPPER trial is a multicenter, parallel-group, single blinded, randomized controlled superiority study. A total of 356 patients undergoing EMR for large (≥ 2 cm) non-pedunculated polyps in the proximal colon will be included and randomized to the clip group or the control group. Prophylactic clipping will be performed in the intervention group to close the resection defect after the EMR with a distance of < 1 cm between the clips. Primary outcome is delayed bleeding within 30 days after EMR. Secondary outcomes are recurrent or residual polyps and clip artifacts during surveillance colonoscopy after 6 months, as well as cost-effectiveness of prophylactic clipping and severity of delayed bleeding. Discussion: The CLIPPER trial is a pragmatic study performed in the Netherlands and is powered to determine the real-time efficacy and cost-effectiveness of prophylactic clipping after EMR of proximal colon polyps ≥ 2 cm in the Netherlands. This study will also generate new data on the achievability of complete closure and the effects of clip placement on scar surveillance after EMR, in order to further promote the debate on the role of prophylactic clipping in everyday clinical practice. Trial registration: ClinicalTrials.gov NCT03309683. Registered on 13 October 2017. Start recruitment: 05 March 2018. Planned completion of recruitment: 31 August 2021

    Transanal minimally invasive surgery (TAMIS) versus endoscopic submucosal dissection (ESD) for resection of non-pedunculated rectal lesions (TRIASSIC study): Study protocol of a European multicenter randomised controlled trial

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    Background: In the recent years two innovative approaches have become available for minimally invasive en bloc resections of large non-pedunculated rectal lesions (polyps and early cancers). One is Transanal Minimally Invasive Surgery (TAMIS), the other is Endoscopic Submucosal Dissection (ESD). Both techniques are standard of care, but a direct randomised comparison is lacking. The choice between either of these procedures is dependent on local expertise or availability rather than evidence-based. The European Society for Endoscopy has recommended that a comparison between ESD and local surgical resection is needed to guide decision making for the optimal approach for the removal of large rectal lesions in Western countries. The aim of this study is to directly compare both procedures in a randomised setting with regard to effectiveness, safety and perceived patient burden. Methods: Multicenter randomised trial in 15 hospitals in the Netherlands. Patients with non-pedunculated lesions > 2 cm, where the bulk of the lesion is below 15 cm from the anal verge, will be randomised between either a TAMIS or an ESD procedure. Lesions judged to be deeply invasive by an expert panel will be excluded. The primary endpoint is the cumulative local recurrence rate at follow-up rectoscopy at 12 months. Secondary endpoints are: 1) Radical (R0-) resection rate; 2) Perceived burden and quality of life; 3) Cost effectiveness at 12 months; 4) Surgical referral rate at 12 months; 5) Complication rate; 6) Local recurrence rate at 6 months. For this non-inferiority trial, the total sample size of 198 is based on an expected local recurrence rate of 3% in the ESD group, 6% in the TAMIS group and considering a difference of less than 6% to be non-inferior. Discussion: This is the first European randomised controlled trial comparing the effectiveness and safety of TAMIS and ESD for the en bloc resection of large non-pedunculated rectal lesions. This is important as the detection rate of these adenomas is expected to further increase with the introduction of colorectal screening programs throughout Europe. This study will therefore support an optimal use of healthcare resources in the future. Trial registration: Netherlands Trial Register, NL7083, 06 July 2018

    Potential of commodity chemicals to become bio-based according to maximum yields and petrochemical prices

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    Carbohydrates are the prevailing biomass components available for bio-based production. The most direct way to convert carbohydrates into commodity chemicals is by one-step conversion at maximum theoretical yield, such as by anaerobic fermentation without side product formation. Considering these hypothetical yields and petrochemical prices in Europe in 2010–2014, a ranking of 58 commodity chemicals was made using a simple model with ethanol as a base case. It was concluded that base chemicals such as lower olefins and benzene-toluene-xylene (BTX) are too cheap and require too much carbohydrate to be produced competitively compared to bioethanol. However, more oxidized products that require multiple conversion steps in petrochemical production, such as adipic acid, acrylic acid, acrylate esters, and 1,4-butanediol, can be produced competitively from carbohydrates if theoretical yields are approached and if processing is efficient. Instead of carbohydrate fermentation, hypothetical photochemical production from CO2 was also considered. Using again a simple model, the same commodity chemicals remained the most attractive ones.BT/Bioprocess EngineeringBT/Design and Engineering Educatio

    Enhanced isobutanol recovery from fermentation broth for sustainable biofuels production

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    Isobutanol is a highly attractive renewable alternative to conventional fossil fuels, with superior fuel properties as compared to ethanol and 1-butanol. Even though the isobutanol production by fermentation has significant potential, complex downstream processing is limiting the wide-spreading of this technology. Accordingly, this original research significantly contributes to the advancement in industrial biofuel production by developing two eco-efficient downstream processes for the industrial-scale recovery of isobutanol (production capacity 50 ktonneIBUT/y), from a highly dilute fermentation broth (>98 wt% water). Vacuum distillation and a novel hybrid combination of gas stripping and vacuum evaporation were coupled with atmospheric azeotropic distillation to recover over 99.9 % of isobutanol as a high-purity product (100 wt%). Advanced heat pumping and heat integration techniques were further implemented to allow the complete electrification of these recovery processes. Furthermore, implementation of these techniques significantly decreased total annual costs (0.131–0.161 $/kgIBUT), reduced energy requirements (0.488–0.807 kWeh/kgIBUT) and lowered CO2 emissions (0.303–0.449 kgCO2/kgIBUT), resulting in highly competitive purification processes. In addition to efficiently recovering isobutanol, the designed downstream processes provide the potential to enhance the fermentation process by recycling all present microorganisms and reducing water demand. Therefore, the results of this original research substantially contribute to the advancement in industrial biotechnology and the wide-spreading of biofuel production

    Effect of  H<sub>2</sub>:CO ration on theoretical carbon yield of bio-syngas and basic oxygen furnace gas fermentation to chemicals:A thermodynamic and metabolic-based approach

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    Syngas fermentation is an up-and-coming technology that uses acetogenic microorganisms to produce ethanol at the commercial scale. Acetogens can produce many different types of products via their metabolic pathway called the Wood Ljugdahl Pathway (WLP). The WLP can natively produce many different fatty acids and alcohols, and with metabolic engineering, other molecules could be produced through syngas fermentation that are not native to the WLP. In this work isopropanol, 3-hydroxybutyric acid, hexanol, octanol, hexanoic acid, butyric acid and lactic acid were assessed for their feasibility to be produced through syngas fermentation. Two syngas cases were analysed; bio-syngas (H2:CO of 1:1.907) and basic oxygen furnace gas (H2:CO of 1:21.667). The feedstock capacity was fixed at 350 ktons/yr based on its availability. Using thermodynamic values, process reactions from the substrate to the product were found. To verify the metabolic feasibility, ATP yields were calculated based on the respective WLPs from the literature. Sensitivity studies of H2:CO ratios on the carbon yield are carried out to check its effect on the production yields of the product, biomass, and CO2. Sensitivity analysis showed that a higher H2:CO ratio in the feedstock will lead to higher production.</p

    Becker muscular dystrophy patients with deletions around exon 51; a promising outlook for exon skipping therapy in Duchenne patients.

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    Item does not contain fulltextTheoretically, 13% of patients with Duchenne muscular dystrophy may benefit from antisense-mediated skipping of exon 51 to restore the reading frame, which results in the production of a shortened dystrophin protein. We give a detailed description with longitudinal follow up of three patients with Becker muscular dystrophy with in-frame deletions in the DMD gene encompassing exon 51. Their internally deleted, but essentially functional, dystrophins are identical to those that are expected as end products in DMD patients treated with the exon 51 skipping therapy. The mild phenotype encourages further development of exon 51 skipping therapy.1 april 201
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