Fujishima and Honda (1972) demonstrated the potential of titanium dioxide (TiO2) semiconductor materials to split water into hydrogen and oxygen in a photo-electrochemical cell. Their work triggered the development of semiconductor photocatalysis for a wide range of environmental and energy applications. One of the most significant scientific and commercial advances to date has been the development of visible light active (VLA) TiO2 photocatalytic materials. In this review, a background on TiO2 structure, properties and electronic properties in photocatalysis is presented. The development of different strategies to modify TiO2 for the utilization of visible light, including non metal and/or metal doping, dye sensitization and coupling semiconductors are discussed. Emphasis is given to the origin of visible light absorption and the reactive oxygen species generated, deduced by physicochemical and photoelectrochemical methods. Various applications of VLA TiO2, in terms of environmental remediation and in particular water treatment, disinfection and air purification, are illustrated. Comprehensive studies on the photocatalytic degradation of contaminants of emerging concern, including endocrine disrupting compounds, pharmaceuticals, pesticides, cyanotoxins and volatile organic compounds, with VLA TiO2 are discussed and compared to conventional UV-activated TiO2 nanomaterials. Recent advances in bacterial disinfection using VLA TiO2 are also reviewed. Issues concerning test protocols for real visible light activity and photocatalytic efficiencies with different light sources have been highlighted.

/pdf/a-review-on-the-visible-light-active-titanium-dioxide-2qg81s4yao.pdf

A review on the visible light active titanium dioxide photocatalysts for environmental applications

Hydrogel delivery systems can leverage therapeutically beneficial outcomes of drug delivery and have found clinical use. Hydrogels can provide spatial and temporal control over the release of various therapeutic agents, including small-molecule drugs, macromolecular drugs and cells. Owing to their tunable physical properties, controllable degradability and capability to protect labile drugs from degradation, hydrogels serve as a platform in which various physiochemical interactions with the encapsulated drugs control their release. In this Review, we cover multiscale mechanisms underlying the design of hydrogel drug delivery systems, focusing on physical and chemical properties of the hydrogel network and the hydrogel-drug interactions across the network, mesh, and molecular (or atomistic) scales. We discuss how different mechanisms interact and can be integrated to exert fine control in time and space over the drug presentation. We also collect experimental release data from the literature, review clinical translation to date of these systems, and present quantitative comparisons between different systems to provide guidelines for the rational design of hydrogel delivery systems.

/pdf/designing-hydrogels-for-controlled-drug-delivery-3k03j5j2j9.pdf

Designing hydrogels for controlled drug delivery.

Nature’s hierarchical materials

Additive manufacturing (AM) alias 3D printing translates computer-aided design (CAD) virtual 3D models into physical objects. By digital slicing of CAD, 3D scan, or tomography data, AM builds objects layer by layer without the need for molds or machining. AM enables decentralized fabrication of customized objects on demand by exploiting digital information storage and retrieval via the Internet. The ongoing transition from rapid prototyping to rapid manufacturing prompts new challenges for mechanical engineers and materials scientists alike. Because polymers are by far the most utilized class of materials for AM, this Review focuses on polymer processing and the development of polymers and advanced polymer systems specifically for AM. AM techniques covered include vat photopolymerization (stereolithography), powder bed fusion (SLS), material and binder jetting (inkjet and aerosol 3D printing), sheet lamination (LOM), extrusion (FDM, 3D dispensing, 3D fiber deposition, and 3D plotting), and 3D bioprinting....

Polymers for 3D Printing and Customized Additive Manufacturing

MUCKE aims to mine a large volume of images, to structure them conceptually and to use this conceptual structuring in order to improve large-scale image retrieval. The last decade witnessed important progress concerning low-level image representations. However, there are a number problems which need to be solved in order to unleash the full potential of image mining in applications. The central problem with low-level representations is the mismatch between them and the human interpretation of image content. This problem can be instantiated, for instance, by the incapability of existing descriptors to capture spatial relationships between the concepts represented or by their incapability to convey an explanation of why two images are similar in a content-based image retrieval framework. We start by assessing existing local descriptors for image classification and by proposing to use co-occurrence matrices to better capture spatial relationships in images. The main focus in MUCKE is on cleaning large scale Web image corpora and on proposing image representations which are closer to the human interpretation of images. Consequently, we introduce methods which tackle these two problems and compare results to state of the art methods. Note: some aspects of this deliverable are withheld at this time as they are pending review. Please contact the authors for a preview.

http://ieeexplore.ieee.org/iel2/4524/12820/00592460.pdf

Image Processing

Generation of an iPS cell line from bone marrow derived mesenchymal stromal cells from an elderly patient

Bone is a remarkable organ because it retains the capacity to regenerate.1 When successful, the healing of a fractured bone results in complete reconstitution of form and function. However, the healing process itself is quite complex and thus prone to failure. Even today, .10% of fracture patients in industrialized countries experience delayed or compromised healing. A high percentage of these patients are elderly persons prone to fracture and compromised healing. Specific treatment options to prevent delayed bone healing in such patients are still unavailable. Currently, patient fracture fixation and treatment are widely managed without specialized concepts for the elderly or for individual patient immune profiles. Growing evidence on the interplay of the immune and skeletal systems during bone healing might offer new possibilities to identifypatientsat risk earlier and suggest new approaches aimed at personalized treatment, depending on the patient’s immune status. Our understanding of the process of regenerative healing has shown that bone repair is a postnatal process that recapitulates embryologic processes of skeletal development.2 Following injury, the healing process is initiated by an inflammatory reaction, with both the innate and adaptive systems as central mediators. The essential role of the immune system also has recently been recognized in all subsequent healing phases, catabolic and anabolic.3,4 The essential role of immune cells in bone healing predestined them as therapeutic targets. Because of the plethora of immune cells with differing functions during specific healing phases, the first priority was the definition of possible targets. Evaluation of immune cell composition in a small cohort of successfully healed versus delayed-healing patients (ranked by delayed return to full weight bearing and bone bridging, identified radiographically and on CT) revealed elevated levels of terminally differentiated CD81 T cells (TEMRA, or effector memory RA T cells ). This immune cell subpopulation negatively influenced the bone healing process through cytokines, delaying the osteogenic differentiation of mesenchymal stromal cells (in vitro).5 Depletion of CD81 T cells in a clinically relevant animal model led to a better healing outcome. The question is whether the adaptive immune system and its memory capacity is a naturally occurring compromise providing a strong defense against pathogens while simultaneously reducing the regenerative healing capacity, particularly because the immunologic memory is developed only in higher vertebrate organisms, and in these organisms, the regenerative capacity is lower—the opposite of that, for example, in a limb-regenerating newt. Aging significantly delays bone fracture healing, but the underlying mechanisms remain unknown. However, inflammaging (ie, chronic inflammation) has been proposed as underlying many of the changes associated with human aging.6 Using lethal irradiation followed by bone marrow transplantation, Katharina Schmidt-Bleek, PhD

Georg N. Duda

Papers

Generation of an iPS cell line from bone marrow derived mesenchymal stromal cells from an elderly patient

Future Treatment Strategies for Delayed Bone Healing: An Osteoimmunologic Approach.

Custom-made composite scaffolds for segmental defect repair in long bones

The decisive early phase of bone regeneration

European Society of Biomechanics S.M. Perren Award 2022: Standardized tibio-femoral implant loads and kinematics.