The wetting reaction of molten eutectic SnPb on Cu leads to Cu-Sn intermetallic compound formation, but not compounds of Cu-Pb since they do not exist. Cu-Sn compounds do not form layered structures between the solder and Cu, rather the Cu 6 Sn 5 phase has grown as scalloplike grains into the molten solder. The scalloplike grains grow larger but fewer with time, indicating that a ripening reaction has occurred among them. However, the ripening is not a constant volume process since it is accompanied by the soldering reaction. Between the scallop grains, there are molten solder channels extending nearly all the way to the Cu interface. In aging, these channels serve as fast diffusion and dissolution paths of Cu in the solder to feed the reaction. A kinetic analysis of the soldering reaction accompanied by the ripening reaction is given. In the analysis, the growth of the scalloplike grains is supplied by two fluxes: the flux of interfacial reaction and the flux of ripening. The latter was formulated by the Gibbs-Thomson equation. The former was obtained by measuring the rate of consumption of Cu in the reaction. The measurement was carried out by determining the change of the total volume of scalloplike grains ͑and in turn, the Cu content in the grains͒ as a function of time and temperature. A reasonable agreement has been obtained between the calculated scallop-grain growth based on kinetic analysis and the experimentally measured values. A discussion of the Cu consumption rate is given, since it is important for applications in electronic packaging technology.

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Introduction Given mounting calls to disclose biomarker test results to research participants, we explored factors underlying decisions by patients with mild cognitive impairment to receive amyloid imaging results. Methods Prospective, qualitative interviews were conducted with 59 participants (30 = mild cognitive impairment patients, 29 = care partners) from the scan arm of a randomized controlled trial on the effects of amyloid PET results disclosure in an Alzheimer Disease Research Center setting. Results Sixty-three percent of the participants were female, with an average age of 72.9 years, and most had greater than a high school level of education (80%). Primary motivations included: (1) better understanding one's mild cognitive impairment etiology and prognosis to plan ahead, and (2) learning one's brain amyloid status for knowledge's sake, regardless of whether the information is actionable. Most participants demonstrated an adequate understanding of the scan's limitations, yet instances of characterizing amyloid PET as a definitive test for Alzheimer's disease occurred. Mention of potential drawbacks, such as negative psychological outcomes, was minimal, even among care partners. Discussion Findings demonstrate a risk of disproportionate focus on possible benefits of testing among amyloid scan candidates and suggest a need to clearly emphasize the limitations of amyloid PET when counseling cognitively impaired patients and their families before testing. Future research should examine whether minimizing drawbacks at the pre-imaging stage has adverse consequences on results disclosure.

Considering the high rate of falls at long-term care facilities and the absence of evidence-based guidelines to prevent them, additional studies on falls at long-term care facilities are necessary. Meanwhile, given prior research that indicates the importance of human resources in the application of such guidelines, continuous investigations are needed as to whether the research outcomes are actually conveyed to nurses.

As calls for transparency in human subjects research grow, investigators conducting Alzheimer’s disease (AD) biomarker research are increasingly required to consider their ethical obligations regarding the return of AD biomarker test results to research participants. When disclosing these test results to potentially vulnerable participants, investigators may face unique challenges to identify adverse events, particularly psychological events. The purpose of this paper is to describe our research team’s experience with developing and implementing a process for enhanced adverse event monitoring following the return of amyloid-β (Aβ) imaging results to research participants with mild cognitive impairment (MCI). Ethical and logistical considerations are presented along with preliminary findings from an ongoing randomized controlled trial of Aβ imaging results disclosure in MCI. Following receipt of amyloid imaging results, participants underwent 14 days of adverse event monitoring using ecological momentary assessment (EMA), a strategy to capture health, behaviors, and mood as they occur in participants’ natural settings in real time. EMA telephone calls were placed at random during waking hours to screen for mood changes. Investigators were alerted for positive depression, anxiety, suicidal ideation screenings, or for two days of failed call attempts. Preliminary feasibility of twenty-four participants with MCI who participated in EMA mood assessments was successfully completed 83% (SD = 0.4) of the time over 14 days with no alerts for anxiety or depression screening items. EMA, when used with standard adverse event monitoring, is a promising and novel approach to maximize early detection of negative psychological reactions following AD biomarker results disclosed in research settings.