In view of their potential applications in sandwich structures, there has been increasing interest in honeycomb networks. Several different types of honeycomb systems have been proposed each exhibiting different mechanical properties. Here we propose a new hexagonal honeycomb structure composed of two different geometrical features: a re‐entrant feature which is known to generate auxetic behavior, and a non re‐entrant feature found in regular hexagonal honeycombs which leads to conventional behavior. This results in a “semi re‐entrant honeycomb” built of alternate conventional and auxetic layers. Finite element analysis and analytical modeling of these honeycombs show that they exhibit a zero Poisson ratio in one direction and a higher than normal Young's modulus in the orthogonal direction. We also show that by virtue of its zero Poisson's ratio, this honeycomb has a natural tendency to form cylindrical shaped curvatures, something which is very difficult to achieve with conventional or auxetic honeycombs.

The CytoSorb adsorber, a blood purification therapy, is able to remove molecules in the 5-60 kDa range which comprises the majority of inflammatory mediators and some endogenous molecules. We aimed to evaluate CytoSorb therapy on clinical outcomes in critically ill patients. A retrospective case series study, from February 2016 to May 2017, was performed in 40 patients with multiple organ failure who received CytoSorb treatment. There were 28 patients with cardiogenic shock, 2 with septic shock, 9 with acute respiratory distress syndrome, and 1 with liver failure. Nineteen patients (47%) underwent extracorporeal membrane oxygenation, 11 (27%) had an intra-aortic balloon pump, 9 (22%) were implanted with Impella, 6 (15%) had a ventricular assist device, and 18 (45%) were treated with continuous veno-venous hemofiltration. After CytoSorb treatment, total bilirubin decreased from 11.6 ± 9.2 to 6.8 ± 5.1 mg/dL (P = 0.005), lactate from 12.1 ± 8.7 to 2.9 ± 2.5 mmol/L (P < 0.001), CPK from 2416 (670-8615) to 281 (44-2769) U/L (P <0.001) and LDH from 1230 (860-3157) to 787 (536-1148) U/L (P <0.001). The vasoactive-inotropic score after 48 h of treatment was reduced to 10 points, P = 0.009. Thirty-day mortality was 55% and ICU mortality was 52.5% at expected ICU mortality of 80%. Our study shows that CytoSorb treatment is effective in reducing bilirubin, lactate, CPK and LDH, in critically ill patients mainly due to cardiogenic shock. There is a need for randomized controlled trials to conclude on the potential benefits blood purification with CytoSorb in critically ill patients.

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Among the different AM techniques, filament-based technology-i.e., fused deposition modeling (FDM)-is the most widely used, and it is also recognized as the best AM technique for functional structures (6). FDM machines can be classified into 2 types: professional and consumer. The professional machines are those produced by the company Stratasys under the trade name Fortus® which, with its founder Scott Crump, developed the original FDM concepts. These machines can operate with acrylonitrile butadiene styrene (ABS) copolymer, nylon (Ny), polycarbonate (PC), and polycarbonate and ABS (PC-ABS), acrylonitrile styrene acrylate (ASA), polyetherimide (PEI) and polyphenylsulfone (PPSF). In recent years, many consumer machines have appeared on the market based on FDM working principles. Consumer machines can operate with poly(lactic acid) (PLA), ABS, polyethylene terephthalate glycol-modified (PETG), Ny and PC.

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Polyetherimide (PEI) blends modified by either polycarbonate (PC) or polyethylene terephthalate glycol-modified (PETG) were prepared. The latter modifier (PETG) was an industrial grade widely used for fused deposition modelling (FDM) printing. PEI blends were compared to Ultem 9085, which is the standard PEI grade for FDM printing in advanced applications. All the blends were thoroughly characterized in terms of their rheological, morphological, thermomechanical and tensile properties. Ultem 9085 showed improved rheology for processing over standard PEI. PEI/PC blends with 10 wt % of modifier developed here closely matched the viscosity behavior of Ultem 9085. On the other hand, the blends with low PC content (i.e., less than 20 wt %) outperformed Ultem 9085 in terms of thermal and tensile properties. When PETG was added, similar tensile properties to Ultem 9085 were found. The immiscibility for PC contents higher than 20 wt % deteriorated the tensile properties, making it less attractive for applications, although melt viscosity decreased further for increasing PC contents.

Thermomechanical and morphological properties of blends of epoxy monomers and hydroxyl and epoxy functionalized hyperbranched polyesters have been studied. Different properties of the blends were found by changing the cure cycles (a precure step followed by a postcure at higher temperature). All the blends showed phase separation with a particulate morphology. Through the addition of the hydroxyl-ended modifiers, rather than the epoxy-ended, an increase of the viscosity and of the reactivity of the uncured blends was obtained. The blends containing the epoxy functionalized polymer showed some liquid-liquid transitions in the rheological traces, probably because of the phase separation phenomena. POLYM. ENG. SCI., 46:1502-1511, 2006.

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