Hydroxyapatite/Mesoporous Graphene/Single‐Walled Carbon Nanotubes Freestanding Flexible Hybrid Membranes for Regenerative Medicine

Freestanding flexible membranes based on biocompatible calcium phosphates are of great interest in regenerative medicine. Here, the authors report the first synthesis of well‐aligned biomimetic hexagonal bars of hydroxyapatite (HAp) on flexible, freestanding mesoporous graphene/single‐walled carbon nanotubes (MG/SWCNT) hybrid membranes. The chemical composition and surface morphology of the HAp coating resemble those of biological apatite. Nitrogen doping and oxygen plasma etching of the MG/SWCNT membranes increase the density of nucleation sites and yield more uniform coatings. This novel membrane favors the attachment and proliferation of human fetal osteoblast (hFOB) osteoprogenitor cells. When soaked in simulated body fluid, enhanced in vitro biomineralization occurs on the hybrid membranes. This hybrid membrane holds great promise in biomedical applications such as patches and strips for spine fusion, bone repair, and restoration of tooth enamel.     

Miniaturisierte thermische Fluidsensoren – Strömungs- und thermische Leitfähigkeitssensoren

Sensors for the determination of fluid and gas properties are being employed for direct and indirect condition monitoring in many application areas of instrumentation and automation. This article presents various robust sensors devised to measure flow properties (velocity, direction, and mass flow) as well as thermal properties (thermal conductivity and diffusivity) of fluids. These sensors are based on a thermal operation principle and can be manufactured with cost-effective microtechnology. Starting from one generic design, they can be implemented and operated as calorimetric flow sensors or thermal conductivity sensors. This article explains the theoretical foundations and discusses several application examples.     

The Need for Advocating Regional Human Comfort Design Codes for Public Spaces: A Case Study of a Mediterranean Urban Park

Though widely acknowledged, climate change and global warming considerations are poorly integrated in landscape planning practices. Exploring this matter, the paper analyses the design of a contemporary urban park in Jaffa, Israel, investigating why climate considerations are so poorly addressed. The analysis focuses on the various competing parameters such as social use, design, political considerations and community desires that influence the planning process as well as the park experience. Results confirm a paradox. Though climate conditions are highly acknowledged, and aggravation in heat stress and discomfort conditions are well known in this region, planners and users alike prefer to suspend them in favour of image and aesthetics. Responding to these results, the paper discusses possible venues for further integrating climate considerations into landscape planning.     

ON CAPACITY MODELING FOR PRODUCTION PLANNING WITH ALTERNATIVE MACHINE TYPES

Analyzing the capacity of production facilities in which manufacturing operations may be performed by alternative machine types presents a seemingly complicated task. In typical enterprise-level production planning models, capacity limitations of alternative machine types are approximated in terms of some single artificial capacitated resource. In this paper we propose procedures for generating compact models that accurately characterize capacity limitations of alternative machine types. Assuming that processing times among alternative machine types are identical or proportional across operations they can perform, capacity limitations of the alternative machine types can be precisely expressed using a formulation that is typically not much larger than the basic linear programming formulation that does not admit alternative resource types. These results have important implications for industrial practice, suggesting that in the case that processing times are nearly proportional among alternatives, the prevalent approximation that involves using a single, capacitated, artificial resource may be dropped in favor of our formulation incorporating the approximation that processing times among the alternatives are proportional. Another advantage is that the set of capacity constraints we formulate can be used to check the feasibility of suggested production schedules or demands simply by plugging mem into the constraints, without need to develop values for allocation variables.     

Synthesis of uniform silver nanoparticles with a controllable size

A new method for the synthesis of uniform silver nanoparticles using a single silver reduction step is presented. Fine control over the nanoparticle's size is achieved by varying the concentration of tannic acid, one of the reducing agents, resulting in uniform nanoparticles in the range of 18 nm to 30 nm in diameter with a standard deviation of less than 15%. Changes in the optical properties of the nanoparticles are correlated with their diameter. As the diameter increases the absorption peak is red-shifted. Specifically, for six different sizes of nanoparticles, ranging from 18 nm to 30 nm in diameter, a red-shift from 401 nm to 410 nm in the absorption peaks is measured. In addition, the extinction coefficient increases as the third power of the nanoparticle radius. Rhodamine 123 adsorbed to 30 nm silver nanoparticles exhibits characteristic Raman spectrum suggesting that these nanoparticles are efficient substrate for surface-enhanced Raman spectroscopy.     

Multi-view Scene Flow Estimation: A View Centered Variational Approach

We present a novel method for recovering the 3D structure and scene flow from calibrated multi-view sequences. We propose a 3D point cloud parametrization of the 3D structure and scene flow that allows us to directly estimate the desired unknowns. A unified global energy functional is proposed to incorporate the information from the available sequences and simultaneously recover both depth and scene flow. The functional enforces multi-view geometric consistency and imposes brightness constancy and piecewise smoothness assumptions directly on the 3D unknowns. It inherently handles the challenges of discontinuities, occlusions, and large displacements. The main contribution of this work is the fusion of a 3D representation and an advanced variational framework that directly uses the available multi-view information. This formulation allows us to advantageously bind the 3D unknowns in time and space. Different from optical flow and disparity, the proposed method results in a nonlinear mapping between the images’ coordinates, thus giving rise to additional challenges in the optimization process. Our experiments on real and synthetic data demonstrate that the proposed method successfully recovers the 3D structure and scene flow despite the complicated nonconvex optimization problem.     

Unusual migration of a foreign body from the gut to a vertebral body

We report a unique case in which a needle was accidentally swallowed and migrated into the vertebral body. Plain films and CT of the spine revealed fragmented, linear, metallic-density material in the L3 vertebral body. The possible mechanisms of the migration are discussed.     

Laterally Controlled Template Electrodeposition of Polyaniline

Polyaniline (PANi) was electrodeposited in gold-coated nanoporous alumina membranes (NAMs) by anodic polymerization of aniline. PANi deposition was followed by cathodic deposition of Ag or Cu, to form a layer of PANi–metal segmented nanowires in the NAM. The compact PANi nanowires fill the entire pore volume, providing a sharp transition from the polymer to the metal segment. The deposited metal layer enables SEM visualization of the PANi nanowire length in the membrane. Deposition of Cu on PANi nanowires occurs at potentials where the PANi is in its reduced leucoemeraldine state, with no evidence for penetration of the metal into the polymer matrix. The mechanism of metal ion reduction on the nonconducting polymer wires is not yet clear. Free-standing segmented PANi–Ag and PANi–Cu nanowires obtained by membrane dissolution show a sharp heterojunction between the polymer and metal phases and are mechanically stable. Aniline electropolymerization in the insulating NAM under a lateral potential gradient generated a thickness gradient of the PANi deposit, revealed by subsequent Cu deposition. The potential-dependent length of the PANi nanowires follows the PANi conductivity pattern, reaching a maximum in the region of stability of the conducting emeraldine phase. The results demonstrate the possibility of obtaining nonlinear graded materials using electrochemical systems showing a complex current–voltage behavior.