Industrial best practices of conceptual process design

Abstract The chemical process industry aims particularly at energy, capital expenditure and variable feedstock cost savings due to fierce global competition, the Kyoto Protocol and requirements for sustainable development. Increasingly conceptual process design methods are used in the industry to achieve these aims. They are used in: • existing processes to renew parts; • process re-designs based on existing feedstocks and catalysts; • innovative processes (new feed stocks, new catalysts, new process routes, new multifunctional equipment). This article is focused on the best industrial conceptual design practices applied for these application areas. To this end we have reviewed methods, which are used in the chemical process industry in the last 15 years. Capital, energy and variable cost savings are indicated for each method. Specific attention is paid to: • functional integration to multi-functional equipment; • heuristic based selection of unit operations and recycle structure; • superstructure based design optimisation with mixed-integer-non-linear programming (MINLP)

Hyaluronic acid-recombinant gelatin gels as a scaffold for soft tissue regeneration

An array of different types of hyaluronic acid (HA)- and collagen-based products is available for filling soft-tissue defects. A major drawback of the current soft-tissue fillers is their inability to induce cell infiltration and new tissue formation. Our aim is to develop novel biodegradable injectable gels which induce soft tissue regeneration, initially resulting in integration and finally replacement of the gel with new autologous tissue. Two reference gels of pure HA, monophasic HA-1 and micronised HA-2, were used. Furthermore, both gels were mixed with recombinant gelatin (RG) resulting in HA-1+RG and HA-2+RG. All gels were subcutaneously injected on the back of rats and explanted after 4 weeks. Addition of RG to HA-1 resulted in stroma formation (neovascularisation and ECM deposition) which was restricted to the outer rim of the HA-1+RG gel. In contrast, addition of RG to HA-2 induced stroma formation throughout the gel. The RG component of the gel was degraded by macrophages and giant cells and subsequently replaced by new vascularised tissue. Immunohistochemical staining showed that the extracellular matrix components collagen I and III were deposited throughout the gel. In conclusion, this study shows the proof of principle that addition of RG to HA-2 results in a novel injectable gel capable of inducing soft tissue regeneration. In this gel HA has a scaffold function whereas the RG component induces new tissue formation, resulting in proper vascularisation and integration of the HA-2+RG gel with the autologous tissue

РАЗРАБОТКА НОВОГО РЕАГЕНТНОГО РЕЖИМА ФЛОТАЦИИ УГЛЕЙ ПАО "ДТЭК ДОБРОПОЛЬСКАЯ ЦОФ"

Совершенст- вование процесса флотации углей, поиск эффективных реагентов и оптималь- ных технологических режимов – один из главных факторов, от которых зависит технологическая и экономическая результативность флотационного обогаще- ния

Marked Changes in Gut Microbiota in Cardio-Surgical Intensive Care Patients:A Longitudinal Cohort Study

Background: Virtually no studies on the dynamics of the intestinal microbiota in patients admitted to the intensive care unit (ICU) are published, despite the increasingly recognized important role of microbiota on human physiology. Critical care patients undergo treatments that are known to influence the microbiota. However, dynamics and extent of such changes are not yet fully understood. To address this topic, we analyzed the microbiota before, during and after planned major cardio surgery that, for the first time, allowed us to follow the microbial dynamics of critical care patients. In this prospective, observational, longitudinal, single center study, we analyzed the fecal microbiota using 16S rRNA gene sequencing. Results: Samples of 97 patients admitted between April 2015 and November 2016 were included. In 32 patients, data of all three time points (before, during and after admission) were available for analysis. We found a large intra-individual variation in composition of gut microbiota. During admission, a significant change in microbial composition occurred in most patients, with a significant increase in pathobionts combined with a decrease in strictly anaerobic gut bacteria, typically beneficial for health. A lower bacterial diversity during admission was associated with longer hospitalization. In most patients analyzed at all three time points, the change in microbiota during hospital stay reverted to the original composition post-discharge. Conclusions: Our study shows that, even with a short ICU stay, patients present a significant change in microbial composition shortly after admission. The unique longitudinal setup of this study displayed a restoration of the microbiota in most patients to baseline composition post-discharge, which demonstrated its great restorative capacity. A relative decrease in benign or even beneficial bacteria and increase of pathobionts shifts the microbial balance in the gut, which could have clinical relevance. In future studies, the microbiota of ICU patients should be considered a good target for optimisation

Effects of Different Human Milk Oligosaccharides on Growth of Bifidobacteria in Monoculture and Co-culture With Faecalibacterium prausnitzii

Human milk oligosaccharides (hMOs) are important bioactive components in mother’s milk contributing to infant health by supporting colonization and growth of gut microbes. In particular, Bifidobacterium genus is considered to be supported by hMOs. Approximately 200 different hMOs have been discovered and characterized, but only a few abundant hMOs can be produced in sufficient amounts to be applied in infant formula. These hMOs are usually supplied in infant formula as single molecule, and it is unknown which and how individual hMOs support growth of individual gut bacteria. To investigate how individual hMOs influence growth of several relevant intestinal bacteria species, we studied the effects of three hMOs (2′-fucosyllactose, 3-fucosyllactose, and 6′-sialyllactose) and an hMO acid hydrolysate (lacto-N-triose) on three Bifidobacteria and one Faecalibacterium and introduced a co-culture system of two bacterial strains to study possible cross-feeding in presence and absence of hMOs. We observed that in monoculture, Bifidobacterium longum subsp. infantis could grow well on all hMOs but in a structure-dependent way. Faecalibacterium prausnitzii reached a lower cell density on the hMOs in stationary phase compared to glucose, while B. longum subsp. longum and Bifidobacterium adolescentis were not able to grow on the tested hMOs. In a co-culture of B. longum subsp. infantis with F. prausnitzii, different effects were observed with the different hMOs; 6′-sialyllactose, rather than 2′-fucosyllactose, 3-fucosyllactose, and lacto-N-triose, was able to promote the growth of B. longum subsp. infantis. Our observations demonstrate that effects of hMOs on the tested gut microbiota are hMO-specific and provide new means to support growth of these specific beneficial microorganisms in the intestine.</p

Reconstruction of the superior vena cava: Benefits of postoperative surveillance and secondary endovascular interventions

AbstractPurpose: Superior vena cava (SVC) reconstructions are rarely performed; therefore the need for surveillance and the results of secondary interventions are unknown. Methods: During a 14-year period 19 patients (11 male, 8 female; mean age 41.9 years, range 8 to 69 years) underwent SVC reconstruction for symptomatic nonmalignant disease. Causes included mediastinal fibrosis (n = 12), indwelling foreign bodies (n = 4), idiopathic thrombosis (n = 2), and antithrombin III deficiency (n = 1). Spiral saphenous vein graft (n = 14), polytetrafluoroethylene (n = 4), or human allograft (n = 1) was implanted. Results: No early death or pulmonary embolism occurred. Four early graft stenoses or thromboses (spiral saphenous vein graft, n = 2, polytetrafluoroethylene, n = 2) required thrombectomy, with success in three. During a mean follow-up of 49.5 months (range, 4.7 to 137 months), 95 imaging studies were performed (average, five per patient; range, one to 10 studies). Venography detected mild or moderate graft stenosis in seven patients; two progressed to severe stenosis. Two additional grafts developed early into severe stenosis. Four of 19 grafts occluded during follow-up (two polytetrafluoroethylene, two spiral saphenous vein graft). Computed tomography failed to identify stenosis in two grafts, magnetic resonance imaging failed to confirm one stenosis and one graft occlusion, and duplex scanning was inconclusive on graft patency in 10 patients. Angioplasty was performed in all four patients with severe stenosis, with simultaneous placement of Wallstents in two. One of the Wallstents occluded at 9 months. Repeat percutaneous transluminal angioplasty was necessary in two patients, with placement of Palmaz stents in one. Only one graft occlusion and one severe graft stenosis occurred beyond 1 year. The primary, primary-assisted, and secondary patency rates were 61%, 78%, and 83% at 1 year and 53%, 70%, and 74% at 5 years, respectively. Conclusions: Long-term secondary patency rates justify SVC grafting for benign disease. Postoperative surveillance with contrast venography is indicated in the first year to detect graft problems. Endovascular techniques may salvage and improve the patency of SVC grafts. (J Vasc Surg 1998;27:287-301.