Chirulen® — ein Halbzeug aus ultrahochmolekularem Polyäthylen für Implantate

Chirulen® – a semifinished material from UHMW-PE for surgical implants This report deals with the development of the joint replacement, especially concerning Chirulen®. This product consists of a semifinished material from UHMW-PE with extremely high purity grade prepared by the Ziegler low pressure polymerisation process. According to biological and clinical tests Chirulen® has proved its worth as artificial limb material because of its excellent physical properties. Its particular advantages are:

• 1 excellent friction and abrasion properties during physiological processes involved in walking, when there is a force of about five times the body weight on the femur bone.
• 2 no marked difference in the physical properties at the sterilization with γ-rays.

The tendency to replace by an artificial limb other damaged joints, e. g. knee, shoulder, elbow, hand and finger joints is increasing. At these constructions the combination metal/UHMW-PE especially is preferred.     

The Pathway to Intelligence: Using Stimuli‐Responsive Materials as Building Blocks for Constructing Smart and Functional Systems

Systems that are intelligent have the ability to sense their surroundings, analyze, and respond accordingly. In nature, many biological systems are considered intelligent (e.g., humans, animals, and cells). For man‐made systems, artificial intelligence is achieved by massively sophisticated electronic machines (e.g., computers and robots operated by advanced algorithms). On the other hand, freestanding materials (i.e., not tethered to a power supply) are usually passive and static. Hence, herein, the question is asked: can materials be fabricated so that they are intelligent? One promising approach is to use stimuli‐responsive materials; these “smart” materials use the energy supplied by a stimulus available from the surrounding for performing a corresponding action. After decades of research, many interesting stimuli‐responsive materials that can sense and perform smart functions have been developed. Classes of functions discussed include practical functions (e.g., targeting and motion), regulatory functions (e.g., self‐regulation and amplification), and analytical processing functions (e.g., memory and computing). The pathway toward creating truly intelligent materials can involve incorporating a combination of these different types of functions into a single integrated system by using stimuli‐responsive materials as the basic building blocks.     

Hüftgelenkersatz – eine tribologische und konstruktive Herausforderung

Artificial hip joints - a challange for ideasconcerning tribology and designing Artificial hip joints are successfully used since two decades. The artificial joint is set up out of a femoral ball head made of a cobalt chromium alloy or alumina ceramic. The ball head is mostly articulating against an acetabular cup made of polyethylene (UHMWPE). The polyethylene wear debris causes osteolysis. Because of the osteolysis the implants will loosen and a revision of the artificial hip joint has to be performed. The objective of all R & D projects is to minimize the polyethylene wear. The state-of-the-art is discussed. There are new materials and methods that offer oppertunities for new combinations. Possibilities, limitations and the successes are discussed. The clinical experience during the last two decades proved that femoral ball heads made of alumina ceramic could reduce the problems of osteolysis.     

Intermetallic growth study on SnAgCu/Cu solder joint interface during thermal aging

The intermetallic compound (IMC) growth behavior at SnAgCu/Cu solder joint interface under different thermal aging conditions was investigated, in order to develop a framework for correlating IMC layer growth behavior between isothermal and thermomechanical cycling (TMC) effects. Based upon an analysis of displacements for actual flip-chip solder joint during temperature cycling, a special bimetallic loading frame with single joint-shear sample as well as TMC tests were designed and used to research the interfacial IMC growth behavior in SnAgCu/Cu solder joint, with a focus on the influence of stress–strain cycling on the growth kinetics. An equivalent model for IMC growth was derived to describe the interfacial Cu-Sn IMC growth behavior subjected to TMC aging as well as isothermal aging based on the proposed “equivalent aging time” and “effective aging time”. Isothermal aging, thermal cycling (TC) and TMC tests were conducted for parameter determination of the IMC growth model as well as the growth kinetic analysis. The SnAgCu/Cu solder joints were isothermally aged at 125, 150 and 175 °C, while the TC and TMC tests were performed within the temperature range from ?40 to 125 °C. The statistical results of IMC layer thickness showed that the IMC growth for TMC was accelerated compared to that of isothermal aging based on the same “effective aging time”. The IMC growth model proposed here is fit for predicting the IMC layer thickness for SnAgCu/Cu solder joint after any isothermal aging time or thermomechanical cycles. In addition, the results of microstructure evolution observation of SnAgCu/Cu solder joint subjected to TMC revealed that the interfacial zone was the weak link of the solder joint, and the interfacial IMC growth had important influence on the thermomechanical fatigue fracture of the solder joint.     

Volume‐Enhanced Raman Scattering Detection of Viruses

Virus detection and analysis are of critical importance in biological fields and medicine. Surface‐enhanced Raman scattering (SERS) has shown great promise in small molecule and even single molecule detection, and can provide fingerprint signals of molecules. Despite the powerful detection capabilities of SERS, the size discrepancy between the SERS “hot spots” (generally, <10 nm) and viruses (usually, sub‐100 nm) yields poor detection reliability of viruses. Inspired by the concept of molecular imprinting, a volume‐enhanced Raman scattering (VERS) substrate composed of hollow nanocones at the bottom of microbowls (HNCMB) is developed. The hollow nanocones of the resulting VERS substrates serve a twofold purpose: 1) extending the region of Raman signal enhancement from the nanocone surface (e.g., surface “hot spots”) to the hollow area within the cone (e.g., volume “hot spots”)—a novel method of Raman signal enhancement, and 2) directing analyte such as viruses of a wide range of sizes to those VERS “hot spots” while simultaneously increasing the surface area contributing to SERS. Using HNCMB VERS substrates, greatly improved Raman signals of single viruses are demonstrated, an achievement with important implications in disease diagnostics and monitoring, biomedical fields, as well as in clinical treatment.     

Technology and health

Technology has revolutionized healthcare over the past 50 years. From pacemakers and artificial joints to organ transplantation our patients have experienced care that has dramatically improved their quality of life. Genomic science offers opportunities for gene therapy as well as new drug development. These developments arise from “virtuous circles” of technology to science to technology that depend upon the physical sciences and mathematics, health sciences, and engineering. All of these components require adequate funding, people who can work at interfaces, and appropriate relationships of Academia to Industry. These advances raise major issues for health care costs, ethics, conflicts of interest, privacy and patient-physician interactions.     

Engineering Aptamer Switches for Multifunctional Stimulus-Responsive Nanosystems

Although RNA and DNA are best known for their capacity to encode biological information, it has become increasingly clear over the past few decades that these biomolecules are also capable of performing other complex functions, such as molecular recognition (e.g., aptamers) and catalysis (e.g., ribozymes). Building on these foundations, researchers have begun to exploit the predictable base-pairing properties of RNA and DNA in order to utilize nucleic acids as functional materials that can undergo a molecular “switching” process, performing complex functions such as signaling or controlled payload release in response to external stimuli including light, pH, ligand-binding and other microenvironmental cues. Although this field is still in its infancy, these efforts offer exciting potential for the development of biologically based “smart materials”. Herein, ongoing progress in the use of nucleic acids as an externally controllable switching material is reviewed. The diverse range of mechanisms that can trigger a stimulus response, and strategies for engineering those functionalities into nucleic acid materials are explored. Finally, recent progress is discussed in incorporating aptamer switches into more complex synthetic nucleic acid-based nanostructures and functionalized smart materials.     

Fabry‐Perot‐based Layer Stacks for Ellipsometric Encoding

Public, hidden, and forensic features either encoded or directly legible are used for authentication. Fabry‐Perot layer stacks as information carriers in combination with imaging ellipsometry as optical read‐out system provide all‐in‐one anti‐counterfeiting capability that may establish the new security level “encoded forensic”. Different layer designs are described with regard to all three security levels: public features (e.g. color and tilt effect) perceptible by the human eye, hidden features (e.g. spectroscopic response in the UV or IR), and forensic features (ellipsometric quantities Ψ and Δ as a function of wavelength λ and angle of incidence AOI). Physically uncloneable functions (PUF) could be realized as a result of a multi‐material and a multi‐parameter deposition approach as well as by means of specific design features of the Fabry‐Perot layer stack. Hence, they are not subject to any reverse engineering strategies. Examples of stratified, micro‐structured, and laser‐modified Fabry‐Perot layer systems are considered that may be used at all perception levels (e.g. human eye, bar code reader, and imaging ellipsometry) for authentication against product counterfeiting and related areas.     

Electric and magnetic combined source integral equations for electromagnetic transmission problems

Various combined source integral equation (CSIE) formulations are developed for the analysis of electromagnetic scattering by three-dimensional arbitrarily shaped homogeneous penetrable objects. The considered CSIE formulations include the classical “electric” CSIE proposed by Mautz and Harrington in 1979, and its dual “magnetic” CSIE as well as mixed “electric–magnetic” and “magnetic–electric” CSIE formulations. Novel discretization schemes by utilizing the primary (Rao–Wilton–Glisson, RWG) and the dual (Buffa–Christiansen, BC) functions are applied to convert the integral equations into matrix equations. These schemes avoid the numerical problems that would appear if the CSIE formulations were discretized with the conventional Galerkin method using the RWG functions only.     

Conjugated Polymer Actuators and Devices: Progress and Opportunities

Conjugated polymers (CPs), as exemplified by polypyrrole, are intrinsically conducting polymers with potential for development as soft actuators or “artificial muscles” for numerous applications. Significant progress has been made in the understanding of these materials and the actuation mechanisms, aided by the development of physical and electrochemical models. Current research is focused on developing applications utilizing the advantages that CP actuators have (e.g., low driving potential and easy to miniaturize) over other actuating materials and on developing ways of overcoming their inherent limitations. CP actuators are available as films, filaments/yarns, and textiles, operating in liquids as well as in air, ready for use by engineers. Here, the milestones made in understanding these unique materials and their development as actuators are highlighted. The primary focus is on the recent progress, developments, applications, and future opportunities for improvement and exploitation of these materials, which possess a wealth of multifunctional properties.     

Mechanically Flexible Conductors for Stretchable and Wearable E‐Skin and E‐Textile Devices

Considerable progress in materials development and device integration for mechanically bendable and stretchable optoelectronics will broaden the application of “Internet‐of‐Things” concepts to a myriad of new applications. When addressing the needs associated with the human body, such as the detection of mechanical functions, monitoring of health parameters, and integration with human tissues, optoelectronic devices, interconnects/circuits enabling their functions, and the core passive components from which the whole system is built must sustain different degrees of mechanical stresses. Herein, the basic characteristics and performance of several of these devices are reported, particularly focusing on the conducting element constituting them. Among these devices, strain sensors of different types, energy storage elements, and power/energy storage and generators are included. Specifically, the advances during the past 3 years are reported, wherein mechanically flexible conducting elements are fabricated from (0D, 1D, and 2D) conducting nanomaterials from metals (e.g., Au nanoparticles, Ag flakes, Cu nanowires), carbon nanotubes/nanofibers, 2D conductors (e.g., graphene, MoS₂), metal oxides (e.g., Zn nanorods), and conducting polymers (e.g., poly(3,4‐ethylenedioxythiophene):poly(4‐styrene sulfonate), polyaniline) in combination with passive fibrotic and elastomeric materials enabling, after integration, the so‐called electronic skins and electronic textiles.     

带低屈服点钢材“延性保险丝”的钢框架盖板连接节点设计方法研究

采用屈服点低、高延性、高耗能能力的低屈服点钢材制作钢框架节点的连接组件,实现耗散地震能量与震后可更换功能叠加,为震后可恢复功能结构提供一种优质解决方案。为提出带低屈服点钢材"延性保险丝"的钢框架盖板连接节点的设计方法,首先采用通用有限元软件ABAQUS建立非线性计算模型,结合已有钢框架螺栓连接节点拟静力试验,验证数值模型的准确性和适用性。在此基础上,探讨不同影响因子对带低屈服点钢材"延性保险丝"的钢框架盖板连接节点工作性能的影响,获得各个影响因子与盖板"结构保险丝"作用的定量关系,最终提出了带低屈服点钢材"延性保险丝"的钢框架盖板连接节点的设计方法和设计流程,并采用实际工程设计算例进行验证。研究结果表明:拼接缝宽度、腹板盖板厚度与梁宽对节点实际承载力系数和盖板"结构保险丝"作用的影响较小;而拼接位置、梁高和翼缘盖板厚度是影响节点实际承载力系数的关键因子,设计不合理时会令"结构保险丝"作用提早失效;基于计算结果拟合得到节点设计承载力系数临界值与拼接位置和梁高的定量表达式,当设计承载力系数小于临界值时,低屈服点钢材盖板"结构保险丝"作用充分发挥;当设计承载力系数大于临界值时,随着设计承载力...     

PCF-MDC体系技术方案及抗震性能试验研究

围绕预制装配式混凝土框架金属消能减震连接体系(PCF-MDC)的关键技术问题,提出2种金属阻尼器、1套可拆卸型连接方案和金属阻尼器设计方法。为验证阻尼器设计方法及连接方案的可行性并研究该体系的抗震性能,设计并制作了"等同现浇"的"湿"框架(PCF)节点、采用狗骨阻尼器(PCF-DB)和双弯曲板阻尼器(PCF-DP)的PCF-MDC节点。通过拟静力试验,对比其破坏形态、滞回性能、承载性能、耗能特性等差异。试验结果表明:PCF-MDC节点的承载力均达到预期设计值,采用双弯曲板阻尼器的PCF-DP节点承载性能更优,安全储备更足;PCF-MDC节点的耗能特性和抗震性能优于"等同现浇"的PCF节点;连接方案能可靠的传递金属阻尼器与预制构件间的内力。金属阻尼器先于预制构件屈服形成的梁铰耗能机制合理有效,且具备"集中损伤"特性,为震后更换阻尼器实现结构功能恢复提供了有利条件。     

Artificial Super Neutrophils for Inflammation Targeting and HClO Generation against Tumors and Infections

Neutrophils are powerful effector leukocytes that play an important role in innate immune systems for opposing tumor progression and ameliorating pathogen infections. Inspired by their distinct functions against tumors and infections, the artificial “super neutrophils” are proposed with excellent inflammation targeting and hypochlorous acid (HClO) generation characteristics for targeting and eliminating malignant tumor cells and pathogens. The “super neutrophils” are fabricated by embedding glucose oxidase (GOx) and chloroperoxidase (CPO) into zeolitic imidazolate framework‐8 (ZIF‐8) for HClO generation via enzymatic cascades, and then encapsulating them with the neutrophil membrane (NM) for inflammation targeting. In vitro and in vivo results indicate that these artificial “super neutrophils” can generate seven times higher reactive HClO than the natural neutrophils for eradicating tumors and infections. The “super neutrophils” demonstrated here with easy fabrication and good neutrophil‐mimicking property exhibit great potential for biomedical applications.     

Kenngrößen von Turbo‐Molekularpumpen

Graphs of “high‐vacuum pressure as a function of backing pressure” (“p_HV versus p_VV”) and “compression as a function of backing pressure” (“K versus p_VV”) are presented in this article. The performance of any turbomolecular pump can be fully and reliably evaluated with the aid of these graphs. Until now these graphs have only seldom been shown in catalogs. The catalogs generally lack the so‐called “limit lines” (“Q as a function of p_{VV, Kmax}”). For a prescribed gas throughput Q, the limit line indicates what minimum pressure must be generated by the backing pump at the fore‐line port of the turbomolecular pump so that a stable pressure exists at the high‐vacuum side of the turbomolecular pump. Using the gas‐type‐specific limit line and the corresponding, usually well‐documented pumping‐speed curve, one can already describe the functional proficiency and performance of a selected combination of turbomolecular pump plus backing pump in an approximate manner – but not yet completely. In this article we also indicate analytical functions which excellently describe the pressure dependence of the compression and pumping speed.     

Complementary Resistive Switching Using Metal–Ferroelectric–Metal Tunnel Junctions

Complementary resistive switching (CRS) devices are receiving attention because they can potentially solve the current‐sneak and current‐leakage problems of memory arrays based on resistive switching (RS) elements. It is shown here that a simple anti‐serial connection of two ferroelectric tunnel junctions, based on BaTiO₃, with symmetric top metallic electrodes and a common, floating bottom nanometric film electrode, constitute a CRS memory element. It allows nonvolatile storage of binary states (“1” = “HRS+LRS” and “0” = “LRS+HRS”), where HRS (LRS) indicate the high (low) resistance state of each ferroelectric tunnel junction. Remarkably, these states have an identical and large resistance in the remanent state, characteristic of CRS. Here, protocols for writing information are reported and it is shown that non‐destructive or destructive reading schemes can be chosen by selecting the appropriate reading voltage amplitude. Moreover, this dual‐tunnel device has a significantly lower power consumption than a single ferroelectric tunnel junction to perform writing/reading functions, as is experimentally demonstrated. These findings illustrate that the recent impressive development of ferroelectric tunnel junctions can be further exploited to contribute to solving critical bottlenecks in data storage and logic functions implemented using RS elements.     

Fatigue strength of a hybrid joint formed between a PA6-GF60 polymer matrix and a S420MC steel insert

A vehicle’s brake pedal is considered to be one of its most important safety components. In the past, vehicle weight-reduction initiatives resulted in a highly optimized design of steel brake pedal with an increased strength-to-weight ratio. However, any further reduction in the weight of the brake pedal is only possible by using combined, i.e., hybrid, materials. In this case the joint between the two different materials in the hybrid arrangement must be as strong as possible. Many methods for improving the joint between two highly dissimilar materials are known from the literature, but conventional joining techniques lack either the fatigue resistance, because of a poor notch-effect design (shape-based joints), or are unsuitable for low-cost serial production (material-based joints). This article presents an innovative approach to joining the reinforcing insert with a glass-fiber-reinforced polyamide 6 (PA6-GF) base structure, where the reinforcing insert is molded into the PA6-GF. The improved shape of the reinforcing insert contributes the required strength, while the PA6-GF base structure provides the final form of the specimen/product. The innovative shape of the metal insert not only provides the strength of the component; it also ensures the proper joint between the two dissimilar materials. For different types of reinforcing inserts static durability tests as well as fatigue-life tests of the insert-PA6-GF-matrix joints were performed. Our experimental research shows that the most promising shape-based hybrid joints reported in the literature are not the best solution when the hybrid joint’s fatigue life is the decisive criterion for a product’s durability.     

Tissue adhesives for meniscus tear repair: an overview of current advances and prospects for future clinical solutions

Menisci are crucial structures in the knee joint as they play important functions in load transfer, maintaining joint stability and in homeostasis of articular cartilage. Unfortunately, ones of the most frequently occurring knee injuries are meniscal tears. Particularly tears in the avascular zone of the meniscus usually do not heal spontaneously and lead to pain, swelling and locking of the knee joint. Eventually, after a (partial) meniscectomy, they will lead to osteoarthritis. Current treatment modalities to repair tears and by that restore the integrity of the native meniscus still carry their drawbacks and a new robust solution is desired. A strong tissue adhesive could provide such a solution and could potentially improve on sutures, which are the current gold standard. Moreover, a glue could serve as a carrier for biological compounds known to enhance tissue healing. Only few tissue adhesives, e.g., Dermabond^® and fibrin glue, are already successfully used in clinical practice for other applications, but are not considered suitable for gluing meniscus tissue due to their sub-optimal mechanical properties or toxicity. There is a growing interest and research field focusing on the development of novel polymer-based tissue adhesives, but up to now, there is no material specially designed for the repair of meniscal tears. In this review, we discuss the current clinical gold standard treatment of meniscal tears and present an overview of new developments in this field. Moreover, we discuss the properties of different tissue adhesives for their potential use in meniscal tear repair. Finally, we formulate recommendations regarding the design criteria of material properties and adhesive strength for clinically applicable glues for meniscal tears.     

Programmable Nano–Bio Interfaces for Functional Biointegrated Devices

A large amount of evidence has demonstrated the revolutionary role of nanosystems in the screening and shielding of biological systems. The explosive development of interfacing bioentities with programmable nanomaterials has conveyed the intriguing concept of nano–bio interfaces. Here, recent advances in functional biointegrated devices through the precise programming of nano–bio interactions are outlined, especially with regard to the rational assembly of constituent nanomaterials on multiple dimension scales (e.g., nanoparticles, nanowires, layered nanomaterials, and 3D‐architectured nanomaterials), in order to leverage their respective intrinsic merits for different functions. Emerging nanotechnological strategies at nano–bio interfaces are also highlighted, such as multimodal diagnosis or “theragnostics”, synergistic and sequential therapeutics delivery, and stretchable and flexible nanoelectronic devices, and their implementation into a broad range of biointegrated devices (e.g., implantable, minimally invasive, and wearable devices). When utilized as functional modules of biointegrated devices, these programmable nano–bio interfaces will open up a new chapter for precision nanomedicine.     

Can artificially intelligent agents really be conscious?

Mind and intelligence are closely related with the consciousness. Indeed, artificial intelligence (AI) is the most promising avenue towards artificial consciousness (AC). However, in literature, consciousness has been considered as the least amenable to being understood or replicated by AI. Further, computational theories of mind (CTMs) render the mind as a computational system and it is treated as a substantial hypothesis within the purview of AI. However, the consciousness, which is a phenomenon of mind, is partially tackled by this theory and it seems that the CTM is not corroborated considerably in this pursuit. Many valuable contributions have been incorporated by the researchers working strenuously in this domain. However, there is still scarcity of globally accepted computational models of consciousness that can be used to design conscious intelligent machines. The contributions of the researchers entail consciousness as a vague, incomplete and human-centred entity. In this paper, attempt has been made to analyse different theoretical and intricate issues pertaining to mind, intelligence and AC. Moreover, this paper discusses different computational models of the consciousness and critically analyses the possibility of generating the machine consciousness as well as identifying the characteristics of conscious machine. Further, different inquisitive questions, e.g., “Is it possible to devise, project and build a conscious machine?”, “Will artificially conscious machines be able to surpass the functioning of artificially intelligent machines?” and “Does consciousness reflect a peculiar way of information processing?” are analysed.