BENKLER REVISITED – VENTURING BEYOND THE OPEN SOURCE SOFTWARE ARENA?

The organizational principles of open source software (OSS) development have challenged traditional theories in economics, organization research and information systems. In a seminal paper, Benkler (2002) provided a comprehensive framework to structure and explain these OSS principles. Coined Commons-Based Peer Production (CBPP), his framework has inspired a large stream of research on OSS. The objective of our paper is to determine whether CBPP also provides a viable framework to investigate projects of open innovation in non-software related domains. Using a case study approach, we focus on four projects that attempt to operate in line with the OSS phenomenon, but deal with tangible outputs (biotechnology, automobiles, entertainment hardware, and public patent review). We show that in general the CBPP framework is well-suited to explain open value creation in these domains. However, we also find several factors which limit its adoption to non-software related arenas

Eye-Tracker-Guided Non-Mechanical Excimer Laser Assisted Penetrating Keratoplasty

Purpose: The purpose of the study was to implement a new eye tracking mask which could be used to guide the laser beam in automated non-mechanical excimer laser assisted penetrating keratoplasty. Materials and methods: A new trephination mask design with an elevated surface geometry has been proposed with a step formation between conical and flat interfaces. Two recipient masks of 7.5/8.0 mm have been manufactured and tested. The masks have outer diameter of 12.5 mm, step formation at 10.5 mm, and slope of conical surfaces 15°. Its functionality has been tested in different lateral positions and tilts on a planar surface, and pig eye experiments. After successful validation on porcine eyes, new masks have been produced and tested on two patients. Results: The build-in eye tracking software of the MEL 70 was always able to capture the masks. It has been shown that the unwanted pigmentation/pattern induced by the laser pulses on the mask surface does not influence the eye-tracking efficiency. The masks could be tracked within the 18 × 14 mm lateral displacement and up to 12° tilt. Two patient cases are demonstrated. No complications were observed during the surgery, although it needs some attention for aligning the mask horizontally before trephination. Stability of eye tracking masks is emphasized by inducing on purpose movements of the patient head. Conclusion: Eye-tracking-guided penetrating keratoplasty was successfully applied in clinical practice, which enables robust tracking criteria within an extended range. It facilitates the automated trephination procedure of excimer laser-assisted penetrating keratoplasty

Single Proton Knock-Out Reactions from 24,25,26F

The cross sections of the single proton knock-out reactions from 24F, 25F, and 26F on a 12C target were measured at energies of about 50 MeV/nucleon. Ground state populations of 6.6+-.9 mb, 3.8+-0.6 mb for the reactions 12C(24F,23O) and 12C(25F,24O) were extracted, respectively. The data were compared to calculations based on the many-body shell model and the eikonal theory. In the reaction 12C(26F,25O) the particle instability of 25O was confirmed

Wound Healing in Mice with High-Fat Diet- or ob Gene-Induced Diabetes-Obesity Syndromes: A Comparative Study

In the past, the genetically diabetic-obese diabetes/diabetes (db/db) and obese/obese (ob/ob) mouse strains were used to investigate mechanisms of diabetes-impaired wound healing. Here we determined patterns of skin repair in genetically normal C57Bl/6J mice that were fed using a high fat diet (HFD) to induce a diabetes-obesity syndrome. Wound closure was markedly delayed in HFD-fed mice compared to mice which had received a standard chow diet (CD). Impaired wound tissue of HFD mice showed a marked prolongation of wound inflammation. Expression of vascular endothelial growth factor (VEGF) was delayed and associated with the disturbed formation of wound margin epithelia and an impaired angiogenesis in the reduced granulation tissue. Normal wound contraction was retarded and disordered. Wound disorders in obese C57Bl/6J mice were paralleled by a prominent degradation of the inhibitor of NFκB (IκB-α) in the absence of an Akt activation. By contrast to impaired wound conditions in ob/ob mice, late wounds of HFD mice did not develop a chronic inflammatory state and were epithelialized after 11 days of repair. Thus, only genetically obese and diabetic ob/ob mice finally developed chronic wounds and therefore represent a better suited experimental model to investigate diabetes-induced wound healing disorders

Negative Poisson's ratio materials via isotropic interactions

We show that under tension, a classical many-body system with only isotropic pair interactions in a crystalline state can, counterintutively, have a negative Poisson's ratio, or auxetic behavior. We derive the conditions under which the triangular lattice in two dimensions and lattices with cubic symmetry in three dimensions exhibit a negative Poisson's ratio. In the former case, the simple Lennard-Jones potential can give rise to auxetic behavior. In the latter case, negative Poisson's ratio can be exhibited even when the material is constrained to be elastically isotropic.Comment: 10 pages, 2 figures, accepted in Physical Review Letter

Biological Surface Coating and Molting Inhibition as Mechanisms of TiO2 Nanoparticle Toxicity in Daphnia magna

The production and use of nanoparticles (NP) has steadily increased within the last decade; however, knowledge about risks of NP to human health and ecosystems is still scarce. Common knowledge concerning NP effects on freshwater organisms is largely limited to standard short-term (≤48 h) toxicity tests, which lack both NP fate characterization and an understanding of the mechanisms underlying toxicity. Employing slightly longer exposure times (72 to 96 h), we found that suspensions of nanosized (∼100 nm initial mean diameter) titanium dioxide (nTiO2) led to toxicity in Daphnia magna at nominal concentrations of 3.8 (72-h EC50) and 0.73 mg/L (96-h EC50). However, nTiO2 disappeared quickly from the ISO-medium water phase, resulting in toxicity levels as low as 0.24 mg/L (96-h EC50) based on measured concentrations. Moreover, we showed that nTiO2 (∼100 nm) is significantly more toxic than non-nanosized TiO2 (∼200 nm) prepared from the same stock suspension. Most importantly, we hypothesized a mechanistic chain of events for nTiO2 toxicity in D. magna that involves the coating of the organism surface with nTiO2 combined with a molting disruption. Neonate D. magna (≤6 h) exposed to 2 mg/L nTiO2 exhibited a “biological surface coating” that disappeared within 36 h, during which the first molting was successfully managed by 100% of the exposed organisms. Continued exposure up to 96 h led to a renewed formation of the surface coating and significantly reduced the molting rate to 10%, resulting in 90% mortality. Because coating of aquatic organisms by manmade NP might be ubiquitous in nature, this form of physical NP toxicity might result in widespread negative impacts on environmental health