Chemical Approaches to Carbon‐Based Metal‐Free Catalysts

Highly active and durable catalysts play a key role in clean energy technologies. However, the high cost, low reserves, and poor stability of noble‐metal‐based catalysts have hindered the large‐scale development of renewable energy. Owing to their low cost, earth abundance, high activity, and excellent stability, carbon‐based metal‐free catalysts (CMFCs) are promising alternatives to precious‐metal‐based catalysts. Although many synthetic methods based on solution, surface/interface, solid state, and noncovalent chemistries have been developed for producing numerous CMFCs with diverse structures and functionalities, there is still a lack of effective approaches to precisely control the structures of active sites. Therefore, novel chemical approaches are needed for the development of highly active and durable CMFCs that are capable of replacing precious‐metal catalysts for large‐scale applications. Herein, a comprehensive and critical review on chemical approaches to CMFCs is given by summarizing important advancements, current challenges, and future perspectives in this emerging field. Through such a critical review, our understanding of CMFCs and the associated synthetic processes will be significantly increased.     

Antigen-specific T lymphocytes regulate lipopolysaccharide-induced apoptosis of dendritic cells in vivo

The potent accessory properties of dendritic cells (DC) develop sequentially during a process termed "maturation." Splenic DC undergo functional maturation in vivo in response to the bacterial product LPS and migrate from the marginal zone to the T cell areas. The redistribution of fully mature DC, which present Ags encountered in the periphery, in the T cell area is likely to result in T cell priming. Unexpectedly, we found that DC rapidly die by apoptosis once they have entered the T cell zone. Injection of OVA peptide in OVA-specific, TCR-transgenic mice strongly delays the LPS-induced apoptosis of DC in situ. We conclude that mature DC are programmed to die unless they receive a survival signal from T cells and that the regulation of DC survival may be a mechanism aimed at controlling the initiation and the termination of the immune response.     

245 GHz接收机芯片片外测试与实验

为了实现太赫兹气体频谱分析传感器,对245 GHz次谐波接收机芯片的片外测试展开研究。建立了245 GHz次谐波接收机片外测试系统以及基于245 GHz接收机芯片及发射机芯片的气体频谱分析传感器片外展示测试系统,对245 GHz次谐波接收机芯片转换增益和带宽进行测试。片外测试系统得到15 dB转换增益和15 GHz带宽;片外展示测试系统得到9 dB转换增益和16 GHz带宽。片外测试系统和片外展示测试系统结果基本吻合。在片外展示测试系统中加入气腔,即构成气体频谱分析传感器。与现有同类型传感器相比,本文的次谐波接收机具有高增益、高带宽、集成本地振荡信号、低功耗等优势,非常适用于消费电子领域小体积的智能气体频谱分析传感器。     

Flexible data anonymization using ARX—Current status and challenges ahead

The race for innovation has turned into a race for data. Rapid developments of new technologies, especially in the field of artificial intelligence, are accompanied by new ways of accessing, integrating, and analyzing sensitive personal data. Examples include financial transactions, social network activities, location traces, and medical records. As a consequence, adequate and careful privacy management has become a significant challenge. New data protection regulations, for example in the EU and China, are direct responses to these developments. Data anonymization is an important building block of data protection concepts, as it allows to reduce privacy risks by altering data. The development of anonymization tools involves significant challenges, however. For instance, the effectiveness of different anonymization techniques depends on context, and thus tools need to support a large set of methods to ensure that the usefulness of data is not overly affected by risk-reducing transformations. In spite of these requirements, existing solutions typically only support a small set of methods. In this work, we describe how we have extended an open source data anonymization tool to support almost arbitrary combinations of a wide range of techniques in a scalable manner. We then review the spectrum of methods supported and discuss their compatibility within the novel framework. The results of an extensive experimental comparison show that our approach outperforms related solutions in terms of scalability and output data quality—while supporting a much broader range of techniques. Finally, we discuss practical experiences with ARX and present remaining issues and challenges ahead.     

An information system architecture for build- and engineer-to-order production of application services

In manufacturing, substantial efficiency gains have been achieved through industrialization. Key concepts of industrialization include standardization, automation, and modularization. Transferring these to IT service production promises increased efficiency. ERP systems apply such concepts and have been an integrating tool for making production for manufacturers more efficient. However, previous research has considered ERP systems for IT service providers either very broadly or only from a business or technical perspective. This article investigates how to apply the ERP system concept comprehensively to a specific type of IT service provider. To this end, application services are prescribed as being composed of three types of configuration models. This helps to achieve a composition of (IT) application services that is comparable to physical parts, and it further supports their management and automated production within an ERP system. An information system architecture with the ERP system at its core is presented. It supports application service production. All relevant service lifecycle phases are considered and a consistent domain model is provided that connects business and technical layer entities. Targeted companies can improve their application service production in terms of quality and efficiency by leveraging this novel automation- and model-based approach.     

Balancing the Fluency-Consistency Tradeoff in Collaborative Information Search with a Recommender Approach

Creative group work can be supported by collaborative search and annotation of Web resources. In this setting, it is important to help individuals both stay fluent in generating ideas of what to search next (i.e., maintain ideational fluency) and stay consistent in annotating resources (i.e., maintain organization). Based on a model of human memory, we hypothesize that sharing search results with other users, such as through bookmarks and social tags, prompts search processes in memory, which increase ideational fluency, but decrease the consistency of annotations, e.g., the reuse of tags for topically similar resources. To balance this tradeoff, we suggest the tag recommender SoMe, which is designed to simulate search of memory from user-specific tag-topic associations. An experimental field study (N = 18) in a workplace context finds evidence of the expected tradeoff and an advantage of SoMe over a conventional recommender in the collaborative setting. We conclude that sharing search results supports group creativity by increasing the ideational fluency, and that SoMe helps balancing the evidenced fluency-consistency tradeoff.     

Explainable image classification with evidence counterfactual

Pattern Analysis and Applications - The complexity of state-of-the-art modeling techniques for image classification impedes the ability to explain model predictions in an interpretable way. A...