We here report on three parallelized designs of the new edge-based droplet generation mechanism, which, unlike existing mechanisms, produces many equally sized droplets simultaneously at a single droplet formation unit. Operation of the scaled-out systems is straight forward; only the oil inlet pressure has to be controlled to let all the units produce oil droplets, given certain basic design constraints. For systems with a typical nozzle depth of 1.2 microm, the mean droplet diameter is 7.5 microm and the coefficient of variation is below 10%. The number of droplets that is formed per unit can easily be increased by increasing the length of the unit. The stable pressure range in which monodisperse droplets are formed can be extended by small adjustments to the design. Overall, the EDGE devices are simple in design and robust in use, making them suitable for massive outscaling.

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Abstract-It is shown, that the sensitivity of the effective refractive index on the cladding index in evanescent optical waveguide sensors, can be larger than unity. This implies that the attenuation of a guided wave propagating in a waveguide immersed in an absorptive medium can be made larger than that of a free-space wave propagating through the same medium. The conditions and physical explanation for this puzzling behavior are identified and as a practical application, an absorption sensor, based on a suspended silicon slab waveguide, is proposed where the sensitivity is enhanced by a factor of 1.35.

Preprosthetic surgery has become a routine procedure to obtain sufficient bone quantity and quality for dental implant installation in patients with an initial inadequate bone volume. Although autologous bone onlay or inlay grafting is still the preferred bone augmentation technique, a broad range of synthetic bone substitutes have been developed, for example, calcium phosphate cement (CPC). The introduction of porosity within CPC can be used to increase CPC degradation and bone ingrowth. Therefore, three different strategies to obtain porous CPCs were evaluated in this preclinical study. Instantaneously porous CPC (CPC-IP) was compared with delayed porous CPC in vitro and in vivo. CPC-IP was obtained by the creation of CO₂ bubbles during setting, whereas delayed porous CPC was obtained after the degradation of incorporated poly(lactic-co-glycolic acid) (PLGA) microspheres. As an additional aspect, delayed porous CPC was created by the incorporation of either hollow or dense degradable PLGA microspheres (CPC-hPLGA and CPC-dPLGA). All CPC compositions showed appropriate clinical handling properties and an interconnected porous structure with a final porosity above 70% (v/v). In vitro degradation studies showed the gradual formation of pores and further CPC-matrix dissolution for CPCs containing PLGA microspheres (dPLGA microspheres > hPLGA microspheres). For in vivo evaluation of the CPCs, an augmentation model was used, allowing a CPC injection into a rigidly immobilized Teflon ring on the rat skull. Histological evaluation after 12 weeks of implantation showed bone formation using all three CPCs. Bone apposition reached volumetric amounts of up to 10% of the augmentation area and a maximum augmentation height of ∼1 mm. CPC-IP showed significantly more bone formation and resulted in a superior bone apposition height compared with both CPCs containing PLGA microspheres. No differences in biological performance were observed between the CPCs containing hPLGA and those containing dPLGA microspheres. Further research is necessary to enhance the bone appositional speed and amount of CPCs for bone augmentation procedures before them being used in a potential clinical setting.