Highly porous carbons have been produced through an activated pyrolysis process from waste rice straw. The methodology avoids the use of extensive pre-treatments and utilises lower temperatures than ...those previously reported (700 °C), to generate materials suitable for water purification. Activation of rice straw was achieved with carbon dioxide, potassium hydroxide and phosphoric acid to yield porous carbonaceous materials and those prepared with phosphoric acid exhibited an extremely high proportion of mesoporosity (94–95%). The characterisation of the activated carbon demonstrated that rice straw pre-carbonisation at 400 °C prior to activation using potassium hydroxide at 700 °C, resulted in a material with surface area of 1973 m2/g. The pre-carbonised potassium hydroxide activated carbon was demonstrated to be highly effective at the adsorption of methylene blue (cationic dye) and congo red (anionic dye) with the adsorption capacity of 527.6 and 531.4 mg/g respectively. In many cases these adsorption capacities exceeded those of other absorbents previously reported within the literature but importantly require less pre-treatment. An economic assessment of the process demonstrated that these highly porous carbons from waste rice straw are cost competitive with other commercially available activated carbons. These activated carbons may find use as an inexpensive yet effective adsorbents for dye removal and also the mesoporous carbons can be utilised in other applications including catalysis and chromatography.
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Surface modification of a carbon-fiber reinforced epoxy (CF/E) via isophorone diisocyanate amine (IDA) is investigated. The covalently bonded IDA, engendering a microscopically thin layer (2 μm–50 μm ...wide), is an exchange chemical reaction after topically spraying polyurea moieties (isocyanate and amine groups) to curing epoxy that is composed of amine and epoxide groups reacting for tc hours (h). Quasi-static nanoindentation, uniaxial tension and uniaxial compression tests reveal that the chemical bond feature of the tunable IDA surface, conceived at low tc, markedly improves damage tolerance in brittle CF/E by significantly supplementing the energy-release rate (fracture toughness). Compression tests revealed that energy absorption and deflection ductility of IDA-modified CF/E, i.e., C-IDA, and prepared at tc = 0 h, are two and five times greater relative to C-IDA at tc = 0.5 h. Tension tests revealed that energy absorption and deflection ductility of C-IDA at tc = 0 h are 150% and 50% greater than C-IDA at tc = 24 h. Micromechanical properties of the IDA reaction include a uniquely distributed reduced elastic modulus (Er), bounded by moduli of pure epoxy and pure polyurea (overspray). The results, in concert with atomic force microscopy (AFM) and non-negative matrix factorization (NMF) results, validate a link between IDA chemistry and mechanical energy transferability. Manifested as damage localization, fractograph analysis also confirms existence of the link, where bridging of individual damage events in CF/E is markedly reduced.
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•Fractograph analysis confirms marked reduction of bridging of individual damage.•IDA topographies indicate distribution patterns of reduced elastic modulus Er (tc).•Large Er indicate quality IDA, helping to sustain high-strength of carbon-fiber.•Nonlinear model confirms tremendous C-IDA fracture toughness and ductility.
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This study aims to demonstrate a novel method for removing toxic chemicals using soot produced from wood and herbaceous biomass pyrolyzed in a drop tube reactor and tire pyrolytic ...carbon black. The influence of ash content, nanostructure, particle size, and porosity on the filter efficiency of steam activated carbon materials was studied. It has been shown for the first time that steam activated soot and carbon black can remove phenol and chloride with filter efficiencies as high as 95%. The correlation of filter efficiency to material properties showed that the presence of alkali and steam activation time were the key parameters affecting filter efficiencies. This study shows that steam activated biomass soot and tire carbon black are promising alternatives for the cleaning of wastewater.
A surface‐modified carbon‐fiber reinforced epoxy (CF/E) via a unique isophorone diisocyanate amine (IDA) reaction produces a new interfacial epoxy‐polyurea “matrix” (IEPM) that elicits excellent ...mechanical energy transferability in brittle CF/E. The chemical bonding property in the IEPM molecule is produced via moieties of an epoxy mixture and N‐H‐concentrated urea molecules, where IDA thermodynamics are controlled via a curing parameter, tc (in hours). Nano‐scale properties of the IDA reaction, confirmed via fourier‐transform infrared spectroscopy and chemical mapping of molecules comprising the IEPM structure, are linked to bulk mechanical energy transferability, specifically loss modulus, E″(ω), and post‐elastic energy absorption. Using dynamic mechanical analysis (DMA) of six test specimens and a Generalized Maxwell Model – verified via Prony Series calibration of the storage modulus to DMA data to compute relaxation parameters – the ultrathin IEPM is isolated, and E″(ω) is computed as a function of tc. IEPM that is produced via tc = 0 exhibited two, six, and ten times greater loss modulus than IEPM produced via 0.5 ≤ tc ≤ 2; tc = 3.5; and tc = 24 (baseline design utilizes cured CF/E). Finally, IDA surface‐modification of CF/E improved energy absorption capacity (post‐elasticity) between 250% (tc = 0.5) and 300% (tc = 0).
The creation of a new scalable molecule follows epoxy surface modification via isophorone diisocyanate amine reaction. The molecule includes high‐enthalpic isocyanate‐rich urea‐bonds whose thermodynamics and molecular vibrational properties are controlled via curing kinetics. Nano‐scale material changes are linked to designable bulk properties, including loss modulus and post‐elasticity, and are imparted to large‐scale composite structures subject to extreme multi‐hazards forces.
ABSTRACTThe European Society for Paediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) Polyposis Working Group developed recommendations to assist clinicians and health care providers with ...appropriate management of patients with juvenile polyposis. This is the first juvenile polyposis Position Paper published by ESPGHAN with invited experts. Many of the published studies were descriptive and/or retrospective in nature, consequently after incorporating a modified version of the GRADE system many of the recommendations are based on expert opinion. This ESPGHAN Position Paper provides a guide for diagnosis, assessment, and management of juvenile polyposis syndrome in children and adolescents, and will be helpful in the appropriate management and timing of procedures in children and adolescents. The formation of international collaboration and consortia is proposed to monitor patients prospectively to advance our understanding of juvenile polyposis conditions.
Cells rely heavily on microtubules for several processes, including cell division and molecular trafficking. Mutations in the different tubulin-α and -β proteins that comprise microtubules have been ...associated with various diseases and are often dominant, sporadic and congenital. While the earliest reported tubulin mutations affect neurodevelopment, mutations are also associated with other disorders such as bleeding disorders and infertility. We performed a systematic survey of tubulin mutations across all isotypes in order to improve our understanding of how they cause disease, and increase our ability to predict their phenotypic effects. Both protein structural analyses and computational variant effect predictors were very limited in their utility for differentiating between pathogenic and benign mutations. This was even worse for those genes associated with non-neurodevelopmental disorders. We selected tubulin-α and -β disease mutations that were most poorly predicted for experimental characterisation. These mutants co-localise to the mitotic spindle in HeLa cells, suggesting they may exert dominant-negative effects by altering microtubule properties. Our results show that tubulin mutations represent a blind spot for current computational approaches, being much more poorly predicted than mutations in most human disease genes. We suggest that this is likely due to their strong association with dominant-negative and gain-of-function mechanisms.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
In the recent past, we have seen a profusion of scientific articles with observations based on cohorts that were derived from administrative health care databases (AHDs), including the Pediatric ...Health Information System and the Kids’ Inpatient Database, together accounting for 7977 peer reviewed articles since 2000. However, we lack criteria for appraising the validity of the cohorts that investigators derive from the base population. A concerted effort by investigators, editors, and reviewers is needed to qualify and improve this key aspect of study design.
Polypectomy is the most common therapeutic endoscopic intervention in children. Management of sporadic juvenile polyps is limited to polypectomy to resolve symptoms, whereas polyposis syndromes pose ...a multidisciplinary challenge with broader ramifications. In preparation for polypectomy, there are key patient, polyp, endoscopy unit, and provider characteristics that factor into the likelihood of success. Younger age and multiple medical comorbidities increase the risk of adverse outcomes, classified as intraoperative, immediate postoperative, and delayed postoperative complications. Novel techniques, including cold snare polypectomy, can significantly decrease adverse events but a more structured training process for polypectomy in pediatric gastroenterology is needed.
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