We retrospectively reviewed the hospital records of 53 patients admitted for 73 episodes of myasthenic crisis at Columbia-Presbyterian Medical Center over a period of 12 years, from 1983 to 1994. Median age at the onset of first crisis was 55 (range, 20 to 82), the ratio of women to men was 2:1, and the median interval from onset of symptoms to first crisis was 8 months. Infection (usually pneumonia or upper respiratory infection) was the most common precipitating factor (38%), followed by no obvious cause (30%) and aspiration (10%). Twenty-five percent of patients were extubated at 7 days, 50% at 13 days, and 75% at 31 days; the longest crisis exceeded 5 months. Using survival analysis and backward stepwise Cox regression, we identified three independent predictors of prolonged intubation: (1) pre-intubation serum bicarbonate > or = 30 mg/dl (p = 0.0004, relative hazard 4.5), (2) peak vital capacity day 1 to 6 post-intubation < 25 ml/kg (p = 0.001, relative hazard 2.9), and (3) age > 50 (p = 0.01, relative hazard 2.4). The proportion of patients intubated longer than 2 weeks was 0% among those with no risk factors, 21% with one risk factor, 46% with two risk factors, and 88% with three risk factors (p = 0.0004). Complications independently associated with prolonged intubation included atelectasis (p = 0.002), anemia treated with transfusion (p = 0.03), Clostridium difficile infection (p = 0.01), and congestive heart failure (p = 0.03). Three episodes of crisis were fatal, for a mortality rate of 4% (3/73); four additional patients died after extubation. All seven deaths were due to overwhelming medical comorbidity. Over half of those who survived were functionally dependent (home or institutionalized) at discharge. In addition to prospective controlled studies of immunotherapies, the prevention and treatment of medical complications offers the best opportunity for further improving the outcome of myasthenic crisis.

The agronomic and pulping performance of transgenic trees with altered lignin has been evaluated in duplicated, long-term field trials. Poplars expressing cinnamyl alcohol dehydrogenase (CAD) or caffeate/5-hydroxy-ferulate O-methyltransferase (COMT) antisense transgenes were grown for four years at two sites, in France and England. The trees remained healthy throughout the trial. Growth indicators and interactions with insects were normal. No changes in soil microbial communities were detected beneath the transgenic trees. The expected modifications to lignin were maintained in the transgenics over four years, at both sites. Kraft pulping of tree trunks showed that the reduced-CAD lines had improved characteristics, allowing easier delignification, using smaller amounts of chemicals, while yielding more high-quality pulp. This work highlights the potential of engineering wood quality for more environmentally benign papermaking without interfering with tree growth or fitness.

The ability to collaborate has been identified as an essential learning outcome for the 21 st century. However, if group members lack the skills, abilities, and attitudes to work in a team, these groups may work inefficiently or fail to achieve what they set out to do. To achieve success, group members need to engage in productive regulatory processes to manage cognitions, behaviors, motivation, and emotions as needed to attain desired outcomes. One area of regulation that has been underemphasized in collaborative contexts is the regulation of emotions. Therefore, the purpose of this multi-paper dissertation was to examine the emotional experiences of undergraduate students working collaboratively on two online time-limited problem-solving tasks. Using a regulation of learning framework, the research unfolded over four studies drawing from a variety of data sources and building upon one another to explore the socio-emotional aspect of online collaboration. Study 1 (Webster & Hadwin, 2018) provides an overview of students' emotions and plans for emotion regulation, self-reported during two collaborative tasks, offering an in-the-moment picture of how students feel and how they respond to those feelings. Study 2 (Bakhtiar, Webster, & Hadwin, 2018) consisted of a comparative case study to examine differences in regulation and socio-emotional interactions between two groups with contrasting socio-emotional climates. Findings revealed differences between these groups in terms of planning and preparation; therefore, the final two studies examined emotions and emotion regulation strategies reported during groupwork under different levels of planning and preparation at the individual or group level. Study 3 (Webster & Hadwin, 2019) documented the types of strategies students recalled using individually and as a group to regulate a salient emotion during collaboration and compared strategies between groups who were given different types of collaborative planning support. Finally, Study 4 (Webster, Davis, & Hadwin, 2019) iv compared emotions, emotion regulation strategies, and evaluations of strategy effectiveness for a purposeful sample of students who were well-prepared versus underprepared for the first of two collaborative working sessions. Four overarching factors emerged from this research as important for productive emotion regulation in online collaboration: (a) planning and preparation, (b) regulating both negative and positive emotions, (c) regulating at both individual and group levels, and (d) providing support for selecting and enacting helpful strategies. With further research, tools and interventions can be improved and utilized to support students to productively regulate in collaborative groups. v Table of Contents Supervisory Committee .

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