2,280 research outputs found

    Environmental Impact of Fused Filament Fabrication: What Is Known from Life Cycle Assessment?

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    This systematic review interrogates the literature to understand what is known about the environmental sustainability of fused filament fabrication, FFF (also known as fused deposition modeling, FDM), based on life cycle assessment (LCA) results. Since substantial energy demand is systematically addressed as one of the main reasons for ecological damage in FFF, mitigation strategies are often based on reducing the printing time (for example, adopting thicker layers) or the embodied energy per part (e.g., by nesting, which means by printing multiple parts in the same job). A key parameter is the infill degree, which can be adjusted to the application requirements while saving printing time/energy and feedstock material. The adoption of electricity from renewable resources is also expected to boost the sustainability of distributed manufacturing through FFF. Meanwhile, bio-based and recycled materials are being investigated as less impactful alternatives to conventional fossil fuel-based thermoplastic filaments

    A structure-function analysis in patients with prekallikrein deficiency.

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    To investigate the structure-function relation in prekallikrein (PK) deficiency. PK is one of the proteins of the contact phase of blood coagulation which at the present time is the object of a revival of interest.All patients with PK deficiency who had been investigated by molecular biology techniques are the object of the present investigation. Details of patients were obtained from personal files and a time-unlimited PubMed search. Only cases with a molecular-biology-based diagnosis were included.Twelve families were included. The total number of missense mutation was 10, together with 3 stop codons and 2 insertions. These mutations involved mainly exons 11 and 14. There were eight proved homozygotes and three compound heterozygotes. In one instance, homozygosity was probable but not proved. In nine cases, the defect was Type I, whereas it was Type II in the remaining three. No bleeding manifestations were present in 11 of the 12 probands. One proband had epistaxis, but she had hypertension. Altogether, four patients had hypertension and one of them had also two myocardial infarctions.Despite the paucity of cases, it was established that the majority of mutations involved the catalytic domain. It is auspicable that future reports of patients with this disorder should include molecular studies. This would certainly contribute to the understanding of the contact phase of blood coagulation

    Comparison of Bacterial and Archaeal Microbiome in Two Bioreactors Fed with Cattle Sewage and Corn Biomass

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    The bacterial and archaeal communities of two full-scale biogas producing plants (P1 and P2), associated with a 999 kW cogeneration unit, both located in North Italy, were analyzed at start up and fully operating phases, by means of various molecular approaches: (i) Automated Ribosomal Intergenic Spacer Analysis; (ii) cloning and sequencing of PCR amplicons of archaeal genes 16Srrna and mcrA; (iii) 16S rDNA high throughput next generation sequencing. P1 and P2 use the same technology and both were fed with cattle manure and corn silage. During the study of P1 also the post digester (fed with pig manure) was analyzed. The aim of this research was to characterize the bacterial and archaeal communities in two very similar plants to profile the core microbiota. The results of this analysis highlighted that the two plants (producing comparable quantities of volatile fatty acids, biogas, and energy) differed in anerobic microbiota (Bacteria and Archaea). Notably the methanogenic community of P1 was dominated by the strict acetoclastic Methanosaeta (Methanothrix) (up to 23.05%) and the unculturable Candidatus Methanofastidiosum (up to 32.70%), while P2 was dominated by the acetoclastic, but more substrate-versatile, Methanosarcina archaeal genus (49.19%). The data demonstrated that the performances of plants with identical design, in similar operating conditions, yielding comparable amount of biogas (average of 7237 m3 day−1 and 7916 m3 day−1 respectively for P1 and P2), VFA (1643 mg L− 1 and 1634 mg L−1) and energy recovery (23.90–24 MWh day−1), depend on the stabilization of effective and functionally optimized methanogenic communities, but these communities aretaxonomically different in the two biodigesters

    early life weight patterns and risk of obesity at 5 years a population based cohort study

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    Abstract Childhood obesity is a major public health problem in industrialised countries. Recent studies suggest that obesity in adolescence is associated with characteristics present in early childhood. The aim of this study was to estimate the risk of overweight/obesity at age 5 yr based on BMI percentiles at age 3 and changes in percentiles from birth to 3 years of age. In this population-based study BMI data of 5173 children were collected at ages 3 and 5 yr and were linked to information relative to birth weight. The prevalence of obesity at 5 yr was 4.5%. The risk of obesity for children born large for gestational age was 8.4% while it was 13.8% for children overweight at 3 years and 49.8% for children who were obese at 3 yr, regardless of their previous weight trajectory (the prevalences were 50%, 50% and 53% for stable, moderate and strong increasing trajectory, respectively). BMI percentile at 3 years proved to be an efficient biomarker for sustained obesity at age 5 yr. In practice, if one targeted early preventive interventions to only 15% of the population (3-year-olds affected by overweight/obesity) one can address 80% of children who would be affected by obesity at age 5 yr

    Integrated Approach of Life Cycle Assessment and Experimental Design in the Study of A Model Organic Reaction: New Perspectives in Renewable Vanillin-Derived Chemicals

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    This work is focused on performing a quantitative assessment of the environmental impacts associated with an organic synthesis reaction, optimized using an experimental design approach. A nucleophilic substitution reaction was selected, employing vanillin as the substrate, a phenolic compound widely used in the food industry and of pharmaceutical interest, considering its antioxidant and antitumoral potential. To carry out the reaction, three different solvents have been chosen, namely acetonitrile (ACN), acetone (Ace), and dimethylformamide (DMF). The syntheses were planned with the aid of a multivariate experimental design to estimate the best reaction conditions, which simultaneously allow a high product yield and a reduced environmental impact as computed by Life Cycle Assessment (LCA) methodology. The experimental results highlighted that the reactions carried out in DMF resulted in higher yields with respect to ACN and Ace; these reactions were also the ones with lower environmental impacts. The multilinear regression models allowed us to identify the optimal experimental conditions able to guarantee the highest reaction yields and lowest environmental impacts for the studied reaction. The identified optimal experimental conditions were also validated by experimentally conducting the reaction in those conditions, which indeed led to the highest yield (i.e., 93%) and the lowest environmental impacts among the performed experiments. This work proposes, for the first time, an integrated approach of DoE and LCA applied to an organic reaction with the aim of considering both conventional metrics, such as reaction yield, and unconventional ones, such as environmental impacts, during its lab-scale optimization
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