Efficient regression testing of distributed real-time reactive systems in the context of model-driven development

Software and Systems Modeling - Regression testing is indispensable, especially for real-time distributed systems to ensure that existing functionalities are not affected by changes. Despite recent...     

An evolution of low-field strength MRI

The paper describes the evolution of low-field MRI from the very early pioneering days in the late 70 s until today. It is not meant to give a comprehensive historical account of the development of MRI, but rather to highlight the different research environments then and now. In the early 90 s, when low-field systems below 1.5 T essentially vanished, there were just no reasonable means available to make up for the factor of roughly three in signal-to-noise-ratio (SNR) between 0.5 and 1.5 T. This has drastically changed. Improvements in hardware—closed Helium-free magnets, RF receiver systems and especially much faster gradients, much more flexible sampling schemes including parallel imaging and compressed sensing and especially the use of AI at all stages of the imaging process have made low-field MRI a clinically viable supplement to conventional MRI. Ultralow-field MRI with magnets around 0.05 T are also back and constitute a bold and courageous endeavor to bring MRI to communities, which have neither the means nor the infrastructure to sustain a current standard of care MRI.

     

Nanoliter Liquid Packaging in a Bioresorbable Microsystem by Additive Manufacturing and its Application as a Controlled Drug Delivery Device

Precise packaging of nanoliter amounts of liquid in a microsystem is important for many biomedical applications. However, existing liquid encapsulation technologies have limitations in terms of liquid waste, evaporation, trapped bubbles, and liquid degradation. In this study, multiple additive manufacturing techniques for nanoliter liquid packaging in bioresorbable microsystems is used. Two-photon photolithography is used for bioresorbable reservoir fabrication, while inkjet printing (IJP) is used for precise nanoliter liquid packaging. Dual IJP allows for micro-reservoirs to be filled with precise amounts of drug solution and subsequently and rapidly sealed with a layer of lipids mixed with Fe₃O₄ nanoparticles. Combining these two printing techniques can overcome the previous limitations of liquid encapsulation technologies. To demonstrate the relevance of this technique, a wirelessly activated, bioresorbable multi-reservoir microcapsule that can be used for controlled drug delivery is presented. The microcapsules and their content are shown to be stable during fabrication, storage, and operation. Multiple cargo release events are triggered independently by the local melting of the sealing layer, resulting from magnetically induced Fe₃O₄ nanoparticle heating. The operation of the capsule is demonstrated in tissue phantoms and in vitro cell cultures.     

MPEG—4在多媒体移动通信中的应用研究

从MPEG－4系统层分析了MPEG－4用于多媒体移动通信的可行性,并给出了其中一个基于PDA的目标应用。根据MPEG－4系统的主要任务,采用现代软硬件系统集成方法,对系统实现进行了软硬件划分,开发了一套相应的IP模块,主要包括灵活分路器、同步层析解、同步控制、二进制格式场景（BIFS0译码、对象描述器（OD）译码和视频组合器。     

Programming Delayed Dissolution Into Sacrificial Bioinks For Dynamic Temporal Control of Architecture within 3D-Bioprinted Constructs

Sacrificial printing allows introduction of architectural cues within engineered tissue constructs. This strategy adopts the use of a 3D-printed sacrificial ink that is embedded within a bulk hydrogel which is subsequently dissolved to leave open-channels. However, current conventional sacrificial inks do not recapitulate the dynamic nature of tissue development, such as the temporal presentation of architectural cues matching cellular requirements during different stages of maturation. To address this limitation, a new class of sacrificial inks is developed that exhibits tailorable and programmable delayed dissolution profiles (1–17 days), by exploiting the unique ability of the ruthenium complex and sodium persulfate initiating system to crosslink native tyrosine groups present in non-chemically modified gelatin. These novel sacrificial inks are also shown to be compatible with a range of biofabrication technologies, including extrusion-based printing, digital-light processing, and volumetric bioprinting. Further embedding these sacrificial templates within cell-laden bulk hydrogels displays precise control over the spatial and temporal introduction of architectural features into cell-laden hydrogel constructs. This approach demonstrates the unique capacity of delaying dissolution of sacrificial inks to modulate cell behavior, improving the deposition of mineralized matrix and capillary-like network formation in osteogenic and vasculogenic culture, respectively.