Technical-economic evaluation of abrasive recycling in the suspension fine jet process chain

Abrasive waterjet generation methods such as the conventional injection jet method and the suspension jet method have a strong influence on properties and costs of the machined products, particularly ones made of difficult-to-machine materials, e.g., ceramics. Since recycling may reduce the needed amount of materials significantly, the same holds true for recycling processes and technologies within the process chains of abrasive waterjet methods. In this paper, a methodology for integrated technical-economic evaluation of processes is presented and applied to the process technology of abrasive recycling in the suspension fine jet process chain aiming to show the technology’s technical as well as economic potential. Research and development regarding such processes and technologies may contribute to gain competitive advantages for companies as they can differentiate from competitors by offering or processing materials with distinctive properties and/or lower prices causing customer’s benefit. Consequently, it is also of great importance for companies applying waterjet cutting methods to know whether and which recycling technologies are promising from both a technical and an economic point of view. Experiments show that a significant share of the input material (abrasive particles) can be reused after recycling. The monetary appraisal reveals that technical potential results in considerably lower costs compared to the suspension jet method without recycling.     

Activity-tracking devices for older adults: comparison and preferences

Universal Access in the Information Society - Research demonstrates that physical activity beneficially influences brain function, quality of life and reduces cardiovascular diseases. Therefore,...     

New Evidence for P-gp-Mediated Export of Amyloid-β Peptides in Molecular,Blood-Brain Barrier and Neuronal Models

Defective clearance mechanisms lead to the accumulation of amyloid-beta (Aβ) peptides in the Alzheimer’s brain. Though predominantly generated in neurons, little is known about how these hydrophobic, aggregation-prone, and tightly membrane-associated peptides exit into the extracellular space where they deposit and propagate neurotoxicity. The ability for P-glycoprotein (P-gp), an ATP-binding cassette (ABC) transporter, to export Aβ across the blood-brain barrier (BBB) has previously been reported. However, controversies surrounding the P-gp–Aβ interaction persist. Here, molecular data affirm that both Aβ₄₀ and Aβ₄₂ peptide isoforms directly interact with and are substrates of P-gp. This was reinforced ex vivo by the inhibition of Aβ₄₂ transport in brain capillaries from P-gp-knockout mice. Moreover, we explored whether P-gp could exert the same role in neurons. Comparison between non-neuronal CHO-APP and human neuroblastoma SK-N-SH cells revealed that P-gp is expressed and active in both cell types. Inhibiting P-gp activity using verapamil and nicardipine impaired Aβ₄₀ and Aβ₄₂ secretion from both cell types, as determined by ELISA. Collectively, these findings implicate P-gp in Aβ export from neurons, as well as across the BBB endothelium, and suggest that restoring or enhancing P-gp function could be a viable therapeutic approach for removing excess Aβ out of the brain in Alzheimer’s disease.     

Properties of electrically responsive hydrogels as a potential dynamic tool for biomedical applications

Hydrogels with electric responsive properties are gaining research focus due to increasing demand for miniaturized devices that can be precisely controlled using an external stimulus. Such systems are well suited due to their ability to expand and contract when in contact with different types of fluid. This study reports on the synthesis of a “smart” electroresponsive network, using a neutral, “non‐smart,” biocompatible hydrogel forming building block, Pluronic F127 (PF127), as a starting molecule. The PEO–PPO–PEO copolymer was modified with telechelic methacrylic end functionalities to form a triblock linear prepolymer with crosslinkable end groups (crosslinker). This bifunctional prepolymer, PF127 bismethacrylate (PF127BMA), was copolymerized covalently with anionic methacrylic acid sodium salt groups into a nonsoluble 3D hydrogel network in the presence of redox initiators. The polyelectrolyte domains in the pluronic hydrogel afforded controllable swelling capabilities with volumetric expansion exceeding 8500% in deionized water or 1400% in Krebs solution. The hydrogels were further assessed for their mechanical and electroactive response as a function of increasing acid salt content. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41195.