Traffic-Adaptive and Link-Quality-Aware Communication in Wireless Sensor Networks

This paper is a summary of the main contribu- tions of the PhD thesis published in [1]. The main research contributions of the thesis are driven by the research question how to design simple, yet efficient and robust run-time adaptive resource allocation schemes within the commu- nication stack of Wireless Sensor Network (WSN) nodes. The thesis addresses several problem domains with con- tributions on different layers of the WSN communication stack. The main contributions can be summarized as follows: First, a a novel run-time adaptive MAC protocol is intro- duced, which stepwise allocates the power-hungry radio interface in an on-demand manner when the encountered traffic load requires it. Second, the thesis outlines a metho- dology for robust, reliable and accurate software-based energy-estimation, which is calculated at network run- time on the sensor node itself. Third, the thesis evaluates several Forward Error Correction (FEC) strategies to adap- tively allocate the correctional power of Error Correcting Codes (ECCs) to cope with timely and spatially variable bit error rates. Fourth, in the context of TCP-based communi- cations in WSNs, the thesis evaluates distributed caching and local retransmission strategies to overcome the perfor- mance degrading effects of packet corruption and trans- mission failures when transmitting data over multiple hops. The performance of all developed protocols are eval- uated on a self-developed real-world WSN testbed and achieve superior performance over selected existing ap- proaches, especially where traffic load and channel condi- tions are suspect to rapid variations over time.

Functional Characterization and Comparison of Intercellular Communication in Stem Cell-Derived Cardiomyocytes

One novel treatment strategy for the diseased heart focuses on the use of pluripotent stem cell-derived cardiomyocytes (SC-CMs) to overcome the heart's innate deficiency for self-repair. However, targeted application of SC-CMs requires in-depth characterization of their true cardiogenic potential in terms of excitability and intercellular coupling at cellular level and in multicellular preparations. In this study, we elucidated the electrical characteristics of single SC-CMs and intercellular coupling quality of cell pairs, and concomitantly compared them with well-characterized murine native neonatal and immortalized HL-1 cardiomyocytes. Firstly, we investigated the electrical properties and Ca2+ signaling mechanisms specific to cardiac contraction in single SC-CMs. Despite heterogeneity of the new cardiac cell population, their electrophysiological activity and Ca2+ handling were similar to native cells. Secondly, we investigated the capability of paired SC-CMs to form an adequate subunit of a functional syncytium and analyzed gap junctions and signal transmission by dye transfer in cell pairs. We discovered significantly diminished coupling in SC-CMs compared with native cells, which could not be enhanced by a coculture approach combining SC-CMs and primary CMs. Moreover, quantitative and structural analysis of gap junctions presented significantly reduced connexin expression levels compared with native CMs. Strong dependence of intercellular coupling on gap junction density was further confirmed by computational simulations. These novel findings demonstrate that despite the cardiogenic electrophysiological profile, SC-CMs present significant limitations in intercellular communication. Inadequate coupling may severely impair functional integration and signal transmission, which needs to be carefully considered for the prospective use of SC-CMs in cardiac repair.

Improving Communication in Adolescent Cancer Care: A Multiperspective Study.

BACKGROUND Professionals treating adolescents with cancer must communicate well with them and their parents. Evidence suggests that the communication needs of this population are rarely met. Skills training can improve professional communication, but has been criticized for not being based on the experience of the participants in the clinical encounter. We took a multiperspective approach, drawing on perspectives of former adolescents with cancer, patients' parents, physicians, and nurses with the aim to provide suggestions for improvement in communication in adolescent cancer care. METHODS Adolescent cancer survivors (n = 16), parents (n = 8), pediatric oncologists (n = 12), and pediatric oncology nurses (n = 18) participated in 11 focus groups. They discussed their experiences communicating with each other. Transcripts were analyzed by thematic analysis. RESULTS We identified themes within the following sections: (1) The framework in which professionals communicate with adolescents with cancer (regression in a time of detachment, adolescents' perception and knowledge of illness, cognitive versus legal maturity, "lost in transition" between pediatric and adult oncology); (2) communication difficulties between professionals and patients and parents (professionals and patients/parents identified the other party as the source of difficulties), and (3) effective professional communication (there was some overlap on how doctors and nurses should communicate, along with substantially different expectations for the two professions). CONCLUSIONS The framework within which professionals communicate, the different perspectives on the factors that make communication difficult, and the different expectations regarding good communication by doctors and nurses should be considered when communication skills training courses are developed for professionals who work in adolescent oncology.

Noise peaks influence communication in the operating room. An observational study

Noise peaks are powerful distractors. This study focuses on the impact of noise peaks on surgical teams' communication during 109 long abdominal surgeries. We related measured noise peaks during 5-min intervals to the amount of observed communication during the same interval. Results show that noise peaks are associated with less case-relevant communication; this effect is moderated by the level of surgical experience; case-relevant communications decrease under high noise peak conditions among junior, but not among senior surgeons. However, case-irrelevant communication did not decrease under high noise level conditions, rather there was a trend to more case-irrelevant communication under high noise peaks. The results support the hypothesis that noise peaks impair communication because they draw on attentional resources rather than impairing understanding of communication. As case-relevant communication is important for surgical performance, exposure to high noise peaks in the OR should be minimised especially for less experienced surgeons. Practitioner Summary: This study investigated whether noise during surgeries influenced the communication within surgical teams. During abdominal surgeries, noise levels were measured and communication was observed. Results showed that high noise peaks reduced the frequency of patient-related communication, but did not reduce patient-irrelevant communication. Noise may negatively affect team coordination in surgeries.